StemCell Therapy

Diabetes exacts its toll on many Americans, young and old. For years, researchers have painstakingly dissected this complicated disease caused by the destruction of insulin producing islet cells of the pancreas. Despite progress in understanding the underlying disease mechanisms for diabetes, there is still a paucity of effective therapies. For years investigators have been making slow, but steady, progress on experimental strategies for pancreatic transplantation and islet cell replacement. Now, researchers have turned their attention to adult stem cells that appear to be precursors to islet cells and embryonic stem cells that produce insulin.

For decades, diabetes researchers have been searching for ways to replace the insulin-producing cells of the pancreas that are destroyed by a patient's own immune system. Now it appears that this may be possible. Each year, diabetes affects more people and causes more deaths than breast cancer and AIDS combined. Diabetes is the seventh leading cause of death in the United States today, with nearly 200,000 deaths reported each year. The American Diabetes Association estimates that nearly 16 million people, or 5.9 percent of the United States population, currently have diabetes.

Diabetes is actually a group of diseases characterized by abnormally high levels of the sugar glucose in the bloodstream. This excess glucose is responsible for most of the complications of diabetes, which include blindness, kidney failure, heart disease, stroke, neuropathy, and amputations. Type 1 diabetes, also known as juvenile-onset diabetes, typically affects children and young adults. Diabetes develops when the body's immune system sees its own cells as foreign and attacks and destroys them. As a result, the islet cells of the pancreas, which normally produce insulin, are destroyed. In the absence of insulin, glucose cannot enter the cell and glucose accumulates in the blood. Type 2 diabetes, also called adult-onset diabetes, tends to affect older, sedentary, and overweight individuals with a family history of diabetes. Type 2 diabetes occurs when the body cannot use insulin effectively. This is called insulin resistance and the result is the same as with type 1 diabetesa build up of glucose in the blood.

There is currently no cure for diabetes. People with type 1 diabetes must take insulin several times a day and test their blood glucose concentration three to four times a day throughout their entire lives. Frequent monitoring is important because patients who keep their blood glucose concentrations as close to normal as possible can significantly reduce many of the complications of diabetes, such as retinopathy (a disease of the small blood vessels of the eye which can lead to blindness) and heart disease, that tend to develop over time. People with type 2 diabetes can often control their blood glucose concentrations through a combination of diet, exercise, and oral medication. Type 2 diabetes often progresses to the point where only insulin therapy will control blood glucose concentrations.

Each year, approximately 1,300 people with type 1 diabetes receive whole-organ pancreas transplants. After a year, 83 percent of these patients, on average, have no symptoms of diabetes and do not have to take insulin to maintain normal glucose concentrations in the blood. However, the demand for transplantable pancreases outweighs their availability. To prevent the body from rejecting the transplanted pancreas, patients must take powerful drugs that suppress the immune system for their entire lives, a regimen that makes them susceptible to a host of other diseases. Many hospitals will not perform a pancreas transplant unless the patient also needs a kidney transplant. That is because the risk of infection due to immunosuppressant therapy can be a greater health threat than the diabetes itself. But if a patient is also receiving a new kidney and will require immunosuppressant drugs anyway, many hospitals will perform the pancreas transplant.

Over the past several years, doctors have attempted to cure diabetes by injecting patients with pancreatic islet cellsthe cells of the pancreas that secrete insulin and other hormones. However, the requirement for steroid immunosuppressant therapy to prevent rejection of the cells increases the metabolic demand on insulin-producing cells and eventually they may exhaust their capacity to produce insulin. The deleterious effect of steroids is greater for islet cell transplants than for whole-organ transplants. As a result, less than 8 percent of islet cell transplants performed before last year had been successful.

More recently, James Shapiro and his colleagues in Edmonton, Alberta, Canada, have developed an experimental protocol for transplanting islet cells that involves using a much larger amount of islet cells and a different type of immunosuppressant therapy. In a recent study, they report that [17], seven of seven patients who received islet cell transplants no longer needed to take insulin, and their blood glucose concentrations were normal a year after surgery. The success of the Edmonton protocol is now being tested at 10 centers around the world.

If the success of the Edmonton protocol can be duplicated, many hurdles still remain in using this approach on a wide scale to treat diabetes. First, donor tissue is not readily available. Islet cells used in transplants are obtained from cadavers, and the procedure requires at least two cadavers per transplant. The islet cells must be immunologically compatible, and the tissue must be freshly obtainedwithin eight hours of death. Because of the shortage of organ donors, these requirements are difficult to meet and the waiting list is expected to far exceed available tissue, especially if the procedure becomes widely accepted and available. Further, islet cell transplant recipients face a lifetime of immunosuppressant therapy, which makes them susceptible to other serious infections and diseases.

Before discussing cell-based therapies for diabetes, it is important to understand how the pancreas develops. In mammals, the pancreas contains three classes of cell types: the ductal cells, the acinar cells, and the endocrine cells. The endocrine cells produce the hormones glucagon, somatostatin, pancreatic polypeptide (PP), and insulin, which are secreted into the blood stream and help the body regulate sugar metabolism. The acinar cells are part of the exocrine system, which manufactures digestive enzymes, and ductal cells from the pancreatic ducts, which connect the acinar cells to digestive organs.

In humans, the pancreas develops as an outgrowth of the duodenum, a part of the small intestine. The cells of both the exocrine systemthe acinar cellsand of the endocrine systemthe islet cellsseem to originate from the ductal cells during development. During development these endocrine cells emerge from the pancreatic ducts and form aggregates that eventually form what is known as Islets of Langerhans. In humans, there are four types of islet cells: the insulin-producing beta cells; the alpha cells, which produce glucagon; the delta cells, which secrete somatostatin; and the PP-cells, which produce pancreatic polypeptide. The hormones released from each type of islet cell have a role in regulating hormones released from other islet cells. In the human pancreas, 65 to 90 percent of islet cells are beta cells, 15 to 20 percent are alpha-cells, 3 to 10 percent are delta cells, and one percent is PP cells. Acinar cells form small lobules contiguous with the ducts (see Figure 7.1. Insulin Production in the Human Pancreas). The resulting pancreas is a combination of a lobulated, branched acinar gland that forms the exocrine pancreas, and, embedded in the acinar gland, the Islets of Langerhans, which constitute the endocrine pancreas.

Figure 7.1. Insulin Production in the Human Pancreas. The pancreas is located in the abdomen, adjacent to the duodenum (the first portion of the small intestine). A cross-section of the pancreas shows the islet of Langerhans which is the functional unit of the endocrine pancreas. Encircled is the beta cell that synthesizes and secretes insulin. Beta cells are located adjacent to blood vessels and can easily respond to changes in blood glucose concentration by adjusting insulin production. Insulin facilitates uptake of glucose, the main fuel source, into cells of tissues such as muscle.

( 2001 Terese Winslow, Lydia Kibiuk)

During fetal development, new endocrine cells appear to arise from progenitor cells in the pancreatic ducts. Many researchers maintain that some sort of islet stem cell can be found intermingled with ductal cells during fetal development and that these stem cells give rise to new endocrine cells as the fetus develops. Ductal cells can be distinguished from endocrine cells by their structure and by the genes they express. For example, ductal cells typically express a gene known as cytokeratin-9 (CK-9), which encodes a structural protein. Beta islet cells, on the other hand, express a gene called PDX-1, which encodes a protein that initiates transcription from the insulin gene. These genes, called cell markers, are useful in identifying particular cell types.

Following birth and into adulthood, the source of new islet cells is not clear, and some controversy exists over whether adult stem cells exist in the pancreas. Some researchers believe that islet stem cell-like cells can be found in the pancreatic ducts and even in the islets themselves. Others maintain that the ductal cells can differentiate into islet precursor cells, while others hold that new islet cells arise from stem cells in the blood. Researchers are using several approaches for isolating and cultivating stem cells or islet precursor cells from fetal and adult pancreatic tissue. In addition, several new promising studies indicate that insulin-producing cells can be cultivated from embryonic stem cell lines.

In developing a potential therapy for patients with diabetes, researchers hope to develop a system that meets several criteria. Ideally, stem cells should be able to multiply in culture and reproduce themselves exactly. That is, the cells should be self-renewing. Stem cells should also be able to differentiate in vivo to produce the desired kind of cell. For diabetes therapy, it is not clear whether it will be desirable to produce only beta cellsthe islet cells that manufacture insulinor whether other types of pancreatic islet cells are also necessary. Studies by Bernat Soria and colleagues, for example, indicate that isolated beta cellsthose cultured in the absence of the other types of islet cellsare less responsive to changes in glucose concentration than intact islet clusters made up of all islet cell types. Islet cell clusters typically respond to higher-than-normal concentrations of glucose by releasing insulin in two phases: a quick release of high concentrations of insulin and a slower release of lower concentrations of insulin. In this manner the beta cells can fine-tune their response to glucose. Extremely high concentrations of glucose may require that more insulin be released quickly, while intermediate concentrations of glucose can be handled by a balance of quickly and slowly released insulin.

Isolated beta cells, as well as islet clusters with lower-than-normal amounts of non-beta cells, do not release insulin in this biphasic manner. Instead insulin is released in an all-or-nothing manner, with no fine-tuning for intermediate concentrations of glucose in the blood [5, 18]. Therefore, many researchers believe that it will be preferable to develop a system in which stem or precursor cell types can be cultured to produce all the cells of the islet cluster in order to generate a population of cells that will be able to coordinate the release of the appropriate amount of insulin to the physiologically relevant concentrations of glucose in the blood.

Several groups of researchers are investigating the use of fetal tissue as a potential source of islet progenitor cells. For example, using mice, researchers have compared the insulin content of implants from several sources of stem cellsfresh human fetal pancreatic tissue, purified human islets, and cultured islet tissue [2]. They found that insulin content was initially higher in the fresh tissue and purified islets. However, with time, insulin concentration decreased in the whole tissue grafts, while it remained the same in the purified islet grafts. When cultured islets were implanted, however, their insulin content increased over the course of three months. The researchers concluded that precursor cells within the cultured islets were able to proliferate (continue to replicate) and differentiate (specialize) into functioning islet tissue, but that the purified islet cells (already differentiated) could not further proliferate when grafted. Importantly, the researchers found, however, that it was also difficult to expand cultures of fetal islet progenitor cells in culture [7].

Many researchers have focused on culturing islet cells from human adult cadavers for use in developing transplantable material. Although differentiated beta cells are difficult to proliferate and culture, some researchers have had success in engineering such cells to do this. For example, Fred Levine and his colleagues at the University of California, San Diego, have engineered islet cells isolated from human cadavers by adding to the cells' DNA special genes that stimulate cell proliferation. However, because once such cell lines that can proliferate in culture are established, they no longer produce insulin. The cell lines are further engineered to express the beta islet cell gene, PDX-1, which stimulates the expression of the insulin gene. Such cell lines have been shown to propagate in culture and can be induced to differentiate to cells, which produce insulin. When transplanted into immune-deficient mice, the cells secrete insulin in response to glucose. The researchers are currently investigating whether these cells will reverse diabetes in an experimental diabetes model in mice [6, 8].

These investigators report that these cells do not produce as much insulin as normal islets, but it is within an order of magnitude. The major problem in dealing with these cells is maintaining the delicate balance between growth and differentiation. Cells that proliferate well do not produce insulin efficiently, and those that do produce insulin do not proliferate well. According to the researchers, the major issue is developing the technology to be able to grow large numbers of these cells that will reproducibly produce normal amounts of insulin [9].

Another promising source of islet progenitor cells lies in the cells that line the pancreatic ducts. Some researchers believe that multipotent (capable of forming cells from more than one germ layer) stem cells are intermingled with mature, differentiated duct cells, while others believe that the duct cells themselves can undergo a differentiation, or a reversal to a less mature type of cell, which can then differentiate into an insulin-producing islet cell.

Susan Bonner-Weir and her colleagues reported last year that when ductal cells isolated from adult human pancreatic tissue were cultured, they could be induced to differentiate into clusters that contained both ductal and endocrine cells. Over the course of three to four weeks in culture, the cells secreted low amounts of insulin when exposed to low concentrations of glucose, and higher amounts of insulin when exposed to higher glucose concentrations. The researchers have determined by immunochemistry and ultrastructural analysis that these clusters contain all of the endocrine cells of the islet [4].

Bonner-Weir and her colleagues are working with primary cell cultures from duct cells and have not established cells lines that can grow indefinitely. However the cells can be expanded. According to the researchers, it might be possible in principle to do a biopsy and remove duct cells from a patient and then proliferate the cells in culture and give the patient back his or her own islets. This would work with patients who have type 1 diabetes and who lack functioning beta cells, but their duct cells remain intact. However, the autoimmune destruction would still be a problem and potentially lead to destruction of these transplanted cells [3]. Type 2 diabetes patients might benefit from the transplantation of cells expanded from their own duct cells since they would not need any immunosuppression. However, many researchers believe that if there is a genetic component to the death of beta cells, then beta cells derived from ductal cells of the same individual would also be susceptible to autoimmune attack.

Some researchers question whether the ductal cells are indeed undergoing a dedifferentiation or whether a subset of stem-like or islet progenitors populate the pancreatic ducts and may be co-cultured along with the ductal cells. If ductal cells die off but islet precursors proliferate, it is possible that the islet precursor cells may overtake the ductal cells in culture and make it appear that the ductal cells are dedifferentiating into stem cells. According to Bonner-Weir, both dedifferentiated ductal cells and islet progenitor cells may occur in pancreatic ducts.

Ammon Peck of the University of Florida, Vijayakumar Ramiya of Ixion Biotechnology in Alachua, FL, and their colleagues [13, 14] have also cultured cells from the pancreatic ducts from both humans and mice. Last year, they reported that pancreatic ductal epithelial cells from adult mice could be cultured to yield islet-like structures similar to the cluster of cells found by Bonner-Weir. Using a host of islet-cell markers they identified cells that produced insulin, glucagon, somatostatin, and pancreatic polypeptide. When the cells were implanted into diabetic mice, the diabetes was reversed.

Joel Habener has also looked for islet-like stem cells from adult pancreatic tissue. He and his colleagues have discovered a population of stem-like cells within both the adult pancreas islets and pancreatic ducts. These cells do not express the marker typical of ductal cells, so they are unlikely to be ductal cells, according to Habener. Instead, they express a marker called nestin, which is typically found in developing neural cells. The nestin-positive cells do not express markers typically found in mature islet cells. However, depending upon the growth factors added, the cells can differentiate into different types of cells, including liver, neural, exocrine pancreas, and endocrine pancreas, judged by the markers they express, and can be maintained in culture for up to eight months [20].

The discovery of methods to isolate and grow human embryonic stem cells in 1998 renewed the hopes of doctors, researchers, and diabetes patients and their families that a cure for type 1 diabetes, and perhaps type 2 diabetes as well, may be within striking distance. In theory, embryonic stem cells could be cultivated and coaxed into developing into the insulin-producing islet cells of the pancreas. With a ready supply of cultured stem cells at hand, the theory is that a line of embryonic stem cells could be grown up as needed for anyone requiring a transplant. The cells could be engineered to avoid immune rejection. Before transplantation, they could be placed into nonimmunogenic material so that they would not be rejected and the patient would avoid the devastating effects of immunosuppressant drugs. There is also some evidence that differentiated cells derived from embryonic stem cells might be less likely to cause immune rejection (see Chapter 10. Assessing Human Stem Cell Safety). Although having a replenishable supply of insulin-producing cells for transplant into humans may be a long way off, researchers have been making remarkable progress in their quest for it. While some researchers have pursued the research on embryonic stem cells, other researchers have focused on insulin-producing precursor cells that occur naturally in adult and fetal tissues.

Since their discovery three years ago, several teams of researchers have been investigating the possibility that human embryonic stem cells could be developed as a therapy for treating diabetes. Recent studies in mice show that embryonic stem cells can be coaxed into differentiating into insulin-producing beta cells, and new reports indicate that this strategy may be possible using human embryonic cells as well.

Last year, researchers in Spain reported using mouse embryonic stem cells that were engineered to allow researchers to select for cells that were differentiating into insulin-producing cells [19]. Bernat Soria and his colleagues at the Universidad Miguel Hernandez in San Juan, Alicante, Spain, added DNA containing part of the insulin gene to embryonic cells from mice. The insulin gene was linked to another gene that rendered the mice resistant to an antibiotic drug. By growing the cells in the presence of an antibiotic, only those cells that were activating the insulin promoter were able to survive. The cells were cloned and then cultured under varying conditions. Cells cultured in the presence of low concentrations of glucose differentiated and were able to respond to changes in glucose concentration by increasing insulin secretion nearly sevenfold. The researchers then implanted the cells into the spleens of diabetic mice and found that symptoms of diabetes were reversed.

Manfred Ruediger of Cardion, Inc., in Erkrath, Germany, is using the approach developed by Soria and his colleagues to develop insulin-producing human cells derived from embryonic stem cells. By using this method, the non-insulin-producing cells will be killed off and only insulin-producing cells should survive. This is important in ensuring that undifferentiated cells are not implanted that could give rise to tumors [15]. However, some researchers believe that it will be important to engineer systems in which all the components of a functioning pancreatic islet are allowed to develop.

Recently Ron McKay and his colleagues described a series of experiments in which they induced mouse embryonic cells to differentiate into insulin-secreting structures that resembled pancreatic islets [10]. McKay and his colleagues started with embryonic stem cells and let them form embryoid bodiesan aggregate of cells containing all three embryonic germ layers. They then selected a population of cells from the embryoid bodies that expressed the neural marker nestin (see Appendix B. Mouse Embryonic Stem Cells). Using a sophisticated five-stage culturing technique, the researchers were able to induce the cells to form islet-like clusters that resembled those found in native pancreatic islets. The cells responded to normal glucose concentrations by secreting insulin, although insulin amounts were lower than those secreted by normal islet cells (see Figure 7.2. Development of Insulin-Secreting Pancreatic-Like Cells From Mouse Embryonic Stem Cells). When the cells were injected into diabetic mice, they survived, although they did not reverse the symptoms of diabetes.

Figure 7.2. Development of Insulin-Secreting Pancreatic-Like Cells From Mouse Embryonic Stem Cells. Mouse embryonic stem cells were derived from the inner cell mass of the early embryo (blastocyst) and cultured under specific conditions. The embryonic stem cells (in blue) were then expanded and differentiated. Cells with markers consistent with islet cells were selected for further differentiation and characterization. When these cells (in purple) were grown in culture, they spontaneously formed three-dimentional clusters similar in structure to normal pancreatic islets. The cells produced and secreted insulin. As depicted in the chart, the pancreatic islet-like cells showed an increase in release of insulin as the glucose concentration of the culture media was increased. When the pancreatic islet-like cells were implanted in the shoulder of diabetic mice, the cells became vascularized, synthesized insulin, and maintained physical characteristics similar to pancreatic islets.

( 2001 Terese Winslow, Caitlin Duckwall)

According to McKay, this system is unique in that the embryonic cells form a functioning pancreatic islet, complete with all the major cell types. The cells assemble into islet-like structures that contain another layer, which contains neurons and is similar to intact islets from the pancreas [11]. Several research groups are trying to apply McKay's results with mice to induce human embryonic stem cells to differentiate into insulin-producing islets.

Recent research has also provided more evidence that human embryonic cells can develop into cells that can and do produce insulin. Last year, Melton, Nissim Benvinisty of the Hebrew University in Jerusalem, and Josef Itskovitz-Eldor of the Technion in Haifa, Israel, reported that human embryonic stem cells could be manipulated in culture to express the PDX-1 gene, a gene that controls insulin transcription [16]. In these experiments, researchers cultured human embryonic stem cells and allowed them to spontaneously form embryoid bodies (clumps of embryonic stem cells composed of many types of cells from all three germ layers). The embryoid bodies were then treated with various growth factors, including nerve growth factor. The researchers found that both untreated embryoid bodies and those treated with nerve growth factor expressed PDX-1. Embryonic stem cells prior to formation of the aggregated embryoid bodies did not express PDX-1. Because expression of the PDX-1 gene is associated with the formation of beta islet cells, these results suggest that beta islet cells may be one of the cell types that spontaneously differentiate in the embryoid bodies. The researchers now think that nerve growth factor may be one of the key signals for inducing the differentiation of beta islet cells and can be exploited to direct differentiation in the laboratory. Complementing these findings is work done by Jon Odorico of the University of Wisconsin in Madison using human embryonic cells of the same source. In preliminary findings, he has shown that human embryonic stem cells can differentiate and express the insulin gene [12].

More recently, Itskovitz-Eldor and his Technion colleagues further characterized insulin-producing cells in embryoid bodies [1]. The researchers found that embryonic stem cells that were allowed to spontaneously form embryoid bodies contained a significant percentage of cells that express insulin. Based on the binding of antibodies to the insulin protein, Itskovitz-Eldor estimates that 1 to 3 percent of the cells in embryoid bodies are insulin-producing beta-islet cells. The researchers also found that cells in the embryoid bodies express glut-2 and islet-specific glucokinase, genes important for beta cell function and insulin secretion. Although the researchers did not measure a time-dependent response to glucose, they did find that cells cultured in the presence of glucose secrete insulin into the culture medium. The researchers concluded that embryoid bodies contain a subset of cells that appear to function as beta cells and that the refining of culture conditions may soon yield a viable method for inducing the differentiation of beta cells and, possibly, pancreatic islets.

Taken together, these results indicate that the development of a human embryonic stem cell system that can be coaxed into differentiating into functioning insulin-producing islets may soon be possible.

Ultimately, type 1 diabetes may prove to be especially difficult to cure, because the cells are destroyed when the body's own immune system attacks and destroys them. This autoimmunity must be overcome if researchers hope to use transplanted cells to replace the damaged ones. Many researchers believe that at least initially, immunosuppressive therapy similar to that used in the Edmonton protocol will be beneficial. A potential advantage of embryonic cells is that, in theory, they could be engineered to express the appropriate genes that would allow them to escape or reduce detection by the immune system. Others have suggested that a technology should be developed to encapsulate or embed islet cells derived from islet stem or progenitor cells in a material that would allow small molecules such as insulin to pass through freely, but would not allow interactions between the islet cells and cells of the immune system. Such encapsulated cells could secrete insulin into the blood stream, but remain inaccessible to the immune system.

Before any cell-based therapy to treat diabetes makes it to the clinic, many safety issues must be addressed (see Chapter 10. Assessing Human Stem Cell Safety). A major consideration is whether any precursor or stem-like cells transplanted into the body might revert to a more pluripotent state and induce the formation of tumors. These risks would seemingly be lessened if fully differentiated cells are used in transplantation.

But before any kind of human islet-precursor cells can be used therapeutically, a renewable source of human stem cells must be developed. Although many progenitor cells have been identified in adult tissue, few of these cells can be cultured for multiple generations. Embryonic stem cells show the greatest promise for generating cell lines that will be free of contaminants and that can self renew. However, most researchers agree that until a therapeutically useful source of human islet cells is developed, all avenues of research should be exhaustively investigated, including both adult and embryonic sources of tissue.

Chapter 6|Table of Contents|Chapter 8

Historical content: June 17, 2001

Original post:
7. Stem Cells and Diabetes | stemcells.nih.gov

GABRIELLA FIORINO

We trust our doctors with our lives. However, what is the reaction when some medical professionals allow unsanitary measures and diseases to break out into the population? Four institutions in the U.S. came under fire recently by the FDA for improperly handling microbiological organisms and exposing the public to smallpox after conducting unapproved techniques, endangering hundreds of lives.

The FDA identified four medical centers in California and Florida as utilizing unapproved stem cell therapies for those with cancer and other serious illnesses. One of the institutes, California Stem Cell Treatment Centers, applied a method developed by StemImmune Inc., which consisted of injecting clients with a mixture of the smallpox vaccine and stem cells. Dr. Mark Berman, co-founder of the California center, described their methods as cutting edge therapy for stage-4 cancer patients, as reported by the Los Angeles Times.

The consequences of such methods are worrisome; as the FDA claims exposure to the smallpox vaccine significantly increases the risk of life-threatening complications, including heart inflammation. Perhaps even more troubling is the fact that individuals in contact with those receiving the vaccine may develop similar symptoms, possibly infecting hundreds of others. The FDA is currently investigating how StemImmune Inc. received shipments of the vaccine, as the product is unavailable on the market.

The Stem Cell Clinic of Sunrise, Florida is another facility under investigation by the FDA for taking improper sanitary measures to prevent contamination during their therapies. According to the agency, the clinic refused to permit entry of an FDA inspector without an appointment, which is a violation of federal law. This refusal would not be the first time the Florida institution came under fire. According to the New England Journal of Medicine, three clients suffering from macular degeneration sustained blindness following treatment at the facility.

A variety of sources derive stem cells, including bone marrow, blood, umbilical cords, and controversially, human embryos. These products aid in the development and restoration of healthy human tissue, and help battle cancer, heart disease, and Parkinsons disease, as noted by the University of Utah. These products are also employed for spinal cord injuries, indicating critical applications, as the central nervous system does not naturally permit neuro-regeneration following damage. Excitingly, organs growth for those requiring life-saving transplants is another possible advancement.

These innovations are not without consequences, however. According to the Mayo Clinic, some may develop graft-versus-host disease, a condition in which a donors stem cells attack the patients tissues and organs, possibly leading to death. Risks of brain tumor development are also an increased possibility for those receiving injections in the spinal cord, as abnormal tissue growth may result.

As the FDA investigates unsound practices by the four institutes endangering the lives of hundreds, Americans should not be misled regarding stem cell therapies. Through proper sanitary measures, their uses are a huge medical development, comprising a myriad of medical advantages. Liberty Nation will keep readers up to date regarding the actions of the FDA against the four clinics.

Gabi is a Biomedical Sciences major and manages a Cognitive Neuroscience Research Lab at the University of Central Florida. A Libertarian, Gabi says shes surrounded on by whiny, wannabe anti-capitalists, posting about their victimhood on Facebook.Although leftists often confuse her with privileged white girls, Gabi is Puerto Rican and Italian.Make sense of that, liberals!

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Stem Cells and Mishandling Smallpox - Liberty Nation (registration) (blog)

B. Bick, . Poindexter, UT Med. School/SPL

A depletion of brain cells that produce dopamine is responsible for the mobility problems seen in people with Parkinsons disease.

Japanese researchers report promising results from an experimental therapy for Parkinsons disease that involves implanting neurons made from reprogrammed stem cells into the brain. A trial conducted in monkeys with a version of the disease showed that the treatment improved their symptoms and seemed to be safe, according to a report published on 30 August in Nature1.

The studys key finding that the implanted cells survived in the brain for at least two years without causing any dangerous effects in the body provides a major boost to researchers hopes of testing stem-cell treatments for Parkinsons in humans, say scientists.

Jun Takahashi, a stem-cell scientist at Kyoto University in Japan who led the study, says that his team plans to begin transplanting neurons made from induced pluripotent stem (iPS) cells into people with Parkinsons in clinical trials soon.

The research is also likely to inform several other groups worldwide that are testing different approaches to treating Parkinsons using stem cells, with trials also slated to begin soon.

Nature breaks down the latest research and what it means for the future of stem-cell treatments.

Parkinsons is a neurodegenerative condition caused by the death of cells called dopaminergic neurons, which make a neurotransmitter called dopamine in certain areas of the brain. Because dopamine-producing brain cells are involved in movement, people with the condition experience characteristic tremors and stiff muscles. Current treatments address symptoms of the disease but not the underlying cause.

Researchers have pursued the idea that pluripotent stem cells, which can form any cell type in the body, could replace dead dopamine-making neurons in people with Parkinsons, and thus potentially halt or even reverse disease progression. Embryonic stem cells, derived from human embryos, have this capacity, but they have been the subject of ethical debates. Induced pluripotent stem (iPS) cells, which are made by coaxing adult cells into an emybronic-like state, have the same versatility without the associated ethical concerns.

Takahashis team transformed iPS cells derived from both healthy people and those with Parkinsons into dopamine-producing neurons. They then transplanted these cells into macaque monkeys with a form of the disease induced by a neuron-killing toxin.

The transplanted brain cells survived for at least two years and formed connections with the monkeys brain cells, potentially explaining why the monkeys treated with cells began moving around their cages more frequently.

Crucially, Takahashis team found no sign that the transplanted cells had developed into tumours a key concern with treatments that involve pluripotent cells or that they evoked an immune response that couldnt be controlled with immune-suppressing drugs.

Its addressing a set of critical issues that need to be investigated before one can, with confidence, move to using the cells in humans, says Anders Bjorklund, a neuroscientist at Lund University in Sweden.

I hope we can begin a clinical trial by the end of next year, says Takahashi. Such a trial would be the first iPS cell trial for Parkinson's. In 2014, a Japanese woman in her 70s became the first person to receive cells derived from iPS cells, to treat her macular degeneration.

In theory, iPS cells could be tailor-made for individual patients, which would eliminate the need to use drugs that suppress a possible immune response to foreign tissues.

But customized iPS cells are expensive to make and can take a couple months to derive and grow, Takahashi notes. So his team instead plans to establish iPS cell lines from healthy people and then use immune cell biomarkers to match them to people with Parkinsons in the hope of minimizing the immune response (and therefore the need for drugs to blunt the attack).

In a study described in an accompanying paper in Nature Communications2, Takahashis team implanted into monkeys iPS-cell-derived neurons from different macaques. They found that transplants between monkeys carrying similar white blood cell markers triggered a muted immune reaction.

Earlier this year, Chinese researchers began a Parkinsons trial that used a different approach: giving patients neural-precursor cells made from embryonic stem cells, which are intended to develop into mature dopamine-producing neurons. A year earlier, in a separate trial, patients in Australia received similar cells. But some researchers have expressed concerns that the immature transplanted cells could develop tumour-causing mutations.

Meanwhile, researchers who are part of a Parkinsons stem-cell therapy consortium called GForce-PD, of which Takahashis team is a member, are set to bring still other approaches to the clinic. Teams in the United States, Sweden and the United Kingdom are all planning trials to transplant dopamine-producing neurons made from embryonic stem cells into humans. Previously established lines of embryonic stem cells have the benefit that they are well studied and can be grown in large quantities, and so all trial participants can receive a standardized treatment, notes Bjorklund, also a consortium member.

Jeanne Loring, a stem-cell scientist at the Scripps Research Institute in La Jolla, California, favours transplanting iPS-derived neurons made from a patients own cells. Although expensive, this approach avoids dangerous immunosuppressive drugs, she says. And because iPS cells are established anew for each patient, the lines go through relatively few cell divisions, minimizing the risk that they will develop tumour-causing mutations. Loring hopes to begin her teams trial in 2019. This shouldnt be a race and were cheering for success by all, she says.

Lorenz Studer, a stem-cell scientist at the Memorial Sloan Kettering Cancer Center in New York City who is working on a trial that will use neurons made from embryonic stem cells, says that there are still issues to work out, such as the number of cells needed in each transplant procedure. But he says that the latest study is a sign that we are ready to move forward.

The rest is here:
Reprogrammed cells relieve Parkinson's symptoms in trials - Nature.com

The US Food and Drug Administration indicated Monday that it will be increasing oversight and enforcement to prevent the use of potentially dangerous and unproven stem cell treatments.

The US Food and Drug Administration indicated Monday that it will be increasing oversight and enforcement to prevent the use of potentially dangerous and unproven stem cell treatments.

The US Food and Drug Administration indicated Monday that it will be increasing oversight and enforcement to prevent the use of potentially dangerous and unproven stem cell treatments.

On its website, the agency posted awarning letterthat it sent last week to U.S. Stem Cell Clinic of Sunrise, Florida, accusing the clinic of selling unapproved and nonsterile stem cell treatments and injecting them intravenously or directly into patients spines.

The FDA also said Monday that it sent US marshals last week to StemImmune Inc. of San Diego to seizefive vials of a live virus vaccinereserved for people at high risk of smallpox. After being mixed with stem cells, the unapproved concoction was injected directly into the tumors of cancer patients at California Stem Cell Treatment Centers in Rancho Mirage and Beverly Hills, the FDA said.

Chief Science Officer Kristin Comella of U.S. Stem Cell wrote in astatementthat the company is not violating the law as it is currently written.

It is inappropriate and harmful to state that our clinic is not sterile as we are completely compliant with the regulations for surgical procedures, she wrote. The strict regulations mentioned in the warning letter required to manufacture drugs are not applied to clinics or hospitals.

Comella wrote that the surgical procedure used by the clinic is not subject to the rules for tissue banks which include minimal manipulation and homologous use as described in current federal regulations. She concluded, our clinic is not violating the law as it is currently written.

StemImmune is fully cooperating with the FDA about the development of its stem cell-based investigational cancer therapy, Ulrike Szalay, a spokeswoman for the company, wrote in an email. We look forward to continuing our dialogue with the FDA.

Dr. Elliot B. Lander, co-founder of the California Stem Cell Treatment Center, said it was voluntarily participating in studies for late-stage, no-options cancer patients that had been approved by institutional review boards. The boards are basically bioethics committees, he said, and the one overseeing this study was formed by the International Cell Surgical Society.

We provided our services gratis, for compassionate purposes, and no patient was ever charged, he said. Everything to protect patient safety was done appropriately.

Though the vaccine seized by the FDA falls under the domain of StemImmune, Lander said, we provided autologous stem cells to help carry a viral agent into the cancers. All of the early safety study patient data was submitted in detail to the FDA several months ago. It did show tremendous safety and no adverse events related to the vaccine or cell therapy.

The FDA commissioner, Dr. Scott Gottlieb, issued astatementMonday warning of additional actions in the coming months against a larger pool of actors whose unproven and unsafe products put patients at significant risk.

The International Society for Stem Cell Research commended the FDA for its policy direction and enforcement efforts. President Hans Clevers said the society has been very concerned about reports of patients using unproven stem cell therapies.

Many of these patients have suffered great harm, and even death as a result of using unproven stem cell therapies, Clevers said in a statement. We are hopeful that increased regulatory enforcement against clinics offering unproven treatments will deter this practice and help protect patients.

Ive directed the FDA to launch a new working group to pursue unscrupulous clinics through whatever legally enforceable means are necessary to protect the public health, Gottlieb wrote. We have examples where some of these unproven treatments have clearly harmed patients.

This year, a paper published in the New England Journal of Medicine recounted how three women, ages 72 to 88, with macular degeneration were left blind after a stem cell treatment at an unnamed clinic in Florida in 2015.

I wish it hadnt taken this long, said Leigh Turner, associate professor at the Center for Bioethics at the University of Minnesota. This is a space where the FDA could have taken action four or five years ago as far as making this a policy priority.

Turner said he sees the steps announced Monday as both important and necessary, yet he remains skeptical.

There are important distinctions to be made, and the FDA seems to be making these distinctions in terms of suggesting that they are putting together this working group, a task force, going after businesses marketing unproven interventions, going after businesses making illegitimate or unwarranted claims about stem cell treatment, he said.

Stem cells, like other medical products, generally require FDA approval before they can be marketed. The FDA has not approved any stem cell-based products for use other than cord blood-derived cells, which are blood-forming stem cells, for certain diseases, according to theagencys website.

Gottlieb wrote in his statement its incumbent upon the FDA to make sure the existing legal and regulatory framework is properly defined, with bright lines separating individualized or tailored therapies surgeons are permitted to use from new treatments subject to regulation. Because the field of regenerative medicine is rapidly evolving, he said, close calls may be frequent between what constitutes an individualized treatment and what constitutes an unapproved, possibly harmful medical product.

Turner said Gottliebs statement allowed for a bit of slippage as far as what exactly the FDA is going to do and which businesses they are going to target.

Questions remain as to whether the warning letter is a sign of more letters to come and whether we will see a dramatic increase in such activities from the FDA, Turner said.

FDA spokeswoman Lyndsay Meyer wrote in an email that the agency will seek to take additional actions in the coming months as we address this field, and target those who are clearly stepping over the line.

Yet, Turner asked, what is enough to trigger FDA regulation? Are marketing campaigns and commercial activity enough?

Or do we actually require people being blinded before the FDA does something? he asked, noting that theres a considerable amount of uncertainty in terms of what we should expect in the months ahead. The statement itself doesnt provide clear answers to all those questions.

Susan L. Solomon, CEO of the New York Stem Cell Foundation, a nonprofit research organization, said via a spokesman that the regulation of these clinics is very difficult, so the announcement today that the FDA will be stepping up their oversight should be welcomed and applauded.

Overall, Turner said, the agencys actions should not give all stem cell treatments or doctors performing these regenerative therapies a bad name. There are already effective treatments. If we think about bone transplants as stem cell transplants, its standard of care for certain diseases, he said.

Solomon agreed: There are extremely promising studies and research using stem cells to treat macular degeneration, multiple sclerosis, diabetes and many other devastating diseases. I cannot emphasize enough how exciting and promising the research is.

However, anyone advertising a cure today is simply taking advantage of patients for their own financial gain, she said.

Turner acknowledges the difficulty for patients, who may not easily recognize which stem cell therapies are approved and beneficial and which are not.

If you see a business thats making all sorts of dramatic marketing claims across disease categories, claiming to use fat as a treatment for all sorts of indications, these are all signs to be wary of, he said.

The FDA offersadvice for consumers, Meyer noted, adding that anyone who exploits and deceives patients puts the entire field at risk.

Turner acknowledged stem cell treatments as a very promising area of research, and over time, he expects to see more FDA-approved therapies in the marketplace. The problem, he said, is that many American businesses making claims about stem cell treatments lack proper scientific safety and efficacy data.

Why, for example, didnt California Stem Cell Treatment Centers get a warning letter for all the other treatments they are doing? It leaves me a bit perplexed, he said. Why is the FDA so focused on these vials and not on the broader array of marketing claims that California Stem Cells was making?

Solomon said that by providing unproven treatments to chronically ill or injured patients, these clinics are not only taking advantage of patients, they are muddying the scientific waters of clinical trials that are trying to show whether a treatment does or does not work.

In its statements Monday, the FDA notes the handful of bad actors in the stem cell space, Turner observed. (Meyer repeated the FDAs assertion that its only a small number of unscrupulous actors who have seized on the clinical promise of regenerative medicine.)

Whereas I look and I see hundreds of companies, said Turner, who published apaperon the practice.

Ultimately, Turner is glad for the FDAs actions.

I hope this is a sign that the FDA is going to do a lot more and better regulate this market space so well see whether or not that happens, he said. Its easy to make these bold announcements. The question is going to be whether anything really comes of it.

Read the rest here:
FDA cracks down on stem cell clinics | WPMT FOX43 - FOX43.com

Opening a new era in cancer care, the Food and Drug Administration on Wednesday approved the first treatment that genetically engineers patients' own blood cells into an army of assassins to seek out and destroy childhood leukemia.

The CAR-T cell treatment developed by Novartis Pharmaceuticals Corp. and the University of Pennsylvania is the first type of gene therapy to hit the U.S. market and one in a powerful but expensive wave of custom-made living drugs being tested against blood cancers and some tumors.

FDA called the approval historic.

This is a brand new way of treating cancer, said Dr. Stephan Grupp of Children's Hospital of Philadelphia, who treated the first child with CAR-T cell therapy, a girl who had been near death but now has been cancer-free for five years. That's enormously exciting.

CAR-T treatment uses gene therapy techniques not to fix disease-causing genes but to turbocharge T cells, immune system soldiers that cancer too often can evade. Researchers filter those cells from a patient's blood, reprogram them to harbor a chimeric antigen receptor that zeroes in on cancer, and grow hundreds of millions of copies. Returned to the patient, the revved-up cells can continue multiplying to fight disease for months or years.

Novartis said it would charge $475,000 for the treatment, made from scratch for every patient. But the company said there would be no charge if the patient didn't show a response within a month.

We're entering a new frontier in medical innovation with the ability to reprogram a patient's own cells to attack a deadly cancer, FDA Commissioner Scott Gottlieb said.

This first use of CAR-T therapy is aimed at patients desperately ill with a common pediatric cancer acute lymphoblastic leukemia that strikes more than 3,000 children and young adults in the U.S. each year. While most survive, about 15% relapse despite today's best treatments, and their prognosis is bleak.

In a key study of 63 advanced patients, 83% went into remission. It's not clear how long that benefit lasts: Some patients did relapse months later. The others still are being tracked to see how they fare in the long term.

Still, a far higher percentage of patients go into remission with this therapy than anything else we've seen to date with relapsed leukemia, said Dr. Ted Laetsch of the University of Texas Southwestern Medical Center, one of the study sites. I wouldn't say we know for sure how many will be cured yet by this therapy. There certainly is a hope that some will be.

Most patients suffered side effects that can be grueling, even life-threatening. An immune overreaction called cytokine release syndrome can trigger high fevers, causing plummeting blood pressure and, in severe cases, organ damage, requiring special care to tamp down those symptoms without blocking the cancer attack. Also Wednesday, the FDA designated a treatment for those side effects.

The new CAR-T therapy might replace bone marrow transplants that cost more than half a million dollars, said Grupp, who led the Novartis study.

I don't want to be an apologist for high drug prices in the U.S., Grupp stressed. But if it's the last treatment they need, that's a really significant one-time investment in their wellness, especially in kids who have a whole lifetime ahead of them.

Initially, Novartis' CAR-T version to be sold under the brand name Kymriah will be available only through certain medical centers specially trained to handle the sophisticated therapy and its side effects. Patients' collected immune cells will be frozen and shipped to a Novartis factory in New Jersey that creates each dose, a process the company says should take about three weeks.

While this first use of CAR-T therapy only is aimed at a few hundred U.S. patients a year, it's being tested as a treatment for thousands more.

Kite Pharma Inc.'s similar CAR-T brand, developed by the National Cancer Institute, is expected to win approval later this year to treat aggressive lymphoma, and Juno Therapeutics and other companies are studying their own versions against blood cancers including multiple myeloma.

On Monday, Gilead Sciences Inc. announced that it was buying Santa Monica-based Kite in an $11.9-billion deal.

Analysts said the eventual pricing of the Novartis treatment could be an advantage for Kite.

Since these therapies are unbelievably effective for leukemia, Novartis pricing power is high, said Thomas Shrader, biotechnology analyst at Stifel. That means Kite could piggyback off Novartis price, even though its therapy is aimed at non-Hodgkins lymphoma, which has a lower response rate to the therapy than leukemia does.

Scientists around the country also are trying to make CAR-T therapies that could fight more common solid tumors such as brain, breast or pancreatic cancers a harder next step.

Times staff writer Samantha Masunaga contributed to this report.

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UPDATES:

9:55 a.m.: This article was updated with the price of Novartis therapy.

9:45 a.m.: This article was updated with comments from medical experts and a financial analyst, as well as more details about CAR-T therapy.

This article was originally published at 8:25 a.m.

More:
FDA approves historic 'living drug' treatment to fight childhood leukemia - Los Angeles Times

Michael R. Bishop, MD, specializes in the diagnosis and treatment of lymphomas and leukemias. In particular, he cares for patients with hematologic malignancies that have not responded to first-line treatments. An expert in hematopoietic stem cell transplantation (bone marrow transplantation), Dr. Bishop and his team are working to address the unique social, economic, physiological and biological issues that patients face while undergoing this treatment.

His research focuses on the prevention and treatment of relapse after stem cell transplantation. Relapse is the primary cause of treatment failure and death after stem cell transplantation. He has served as the primary investigator on studies designed to prevent and treat disease recurrence after transplantation. Specifically, he works on ways to enhance immune effects of the transplanted cells against cancer.

Bishop has authored more than 150 peer-reviewed articles, in addition to more than 30 book chapters and two books on cancer treatment and research. He also serves on the editorial board of numerous scientific journals, including Biology of Blood and Marrow Transplantation.

He previously served as a senior investigator and as the clinical head of stem cell transplantation for the National Cancer Institute at the National Institutes of Health.

Two of his patients, now in remission, have told their story publicly:

Motivating a Malignant Immune System

The CAR T-cell Chicago story: One year later

Go here to read the rest:
Dr. Bishop @Uchicagomed Knows CAR T-Cell Therapy Backward and Forward - Newswise (press release)

Increased DNA double-strand breaks in Pol-deficient neural progenitors. Credit: Osaka University

DNA is the computer code that programs every event in the body. Despite the importance of DNA fidelity, as the body develops, cells grow and replicate, DNA is constantly turned over. This repeated process can compromise the DNA, so cells have many DNA repair mechanisms. Using mice, Osaka University scientists report a defect in one type of machinery. DNA polymerase (Pol) causes underdevelopment of the brain's cortices and axonal network. The findings could explain cortical development disorders such as autism and microcephaly.

"Pol is responsible for repairing DNA base damage in the brain. Because many neurological disorders are associated with de novo mutations, we wanted to study how loss of Pol affects neuronal development," said Assistant Professor Noriyuki Sugo, an expert in the study of Pol in brain development.

"We found evidence that Pol has a role in the development of the brain but not other organs, and that its defect causes catastrophic DNA double strand breaks (DSBs) and consequent cell death in certain regions of the developing cortex," he said.

These regions represent one of the earliest stages of cortical development, and the generation of cortical neurons is fundamental for proper neural networking.

In the present study, Sugo and his team prepared mutant mice deficient in Pol. These mice showed a large number of DSBs in neural progenitors, the stem cells that eventually produce neurons. Consequently, many immature neurons died through apoptosis. Furthermore, the mice showed defects in the development of specific brain anatomy and the growth of axon in specific cell types, suggesting both an underdevelopment of the cortex and of neural networking.

"We found that Pol deficiency led to higher neuronal cell death in deeper layers than upper layers of the cortex. The deeper layers were thinner," said Sugo. He added that deeper-layer neurons were marked by a higher rate of DSBs.

Neurons formed in these layers are thought essential to the early stages of neural networking. Thus, even if the cells manage to escape death, the brain circuitry is likely compromised.

Finally, proper development depends on both genetic and epigenetic factors. The correction of DNA damage by Pol is an example of genetic regulation. In addition, the researchers found DNA demethylation, an example of epigenetic regulation, is also abnormal in mice deficient of Pol. Together, Sugo argues the findings are strong evidence for the importance of Pol on proper gene expression in cortical development and provide a new target for the study of associated syndromes and disorders.

"The brain is actively constructed in embryonic stages. Neural progenitors produce many neurons, and their genomic DNA is constantly processed. Defects in Pol function could be a new target for explaining cortical developmental disorders."

Explore further: CD38 gene is identified to be important in postnatal development of the cerebral cortex

More information: Kohei Onishi et al, Genome Stability by DNA polymerase in Neural Progenitors Contributes to Neuronal Differentiation in Cortical Development, The Journal of Neuroscience (2017). DOI: 10.1523/JNEUROSCI.0665-17.2017

Excerpt from:
Faulty DNA repair depresses neural development - Medical Xpress

With more than 50 years of experience studying blood-forming stem cells called hematopoietic stem cells, scientists have developed sufficient understanding to actually use them as a therapy. Currently, no other type of stem cell, adult, fetal or embryonic, has attained such status. Hematopoietic stem cell transplants are now routinely used to treat patients with cancers and other disorders of the blood and immune systems. Recently, researchers have observed in animal studies that hematopoietic stem cells appear to be able to form other kinds of cells, such as muscle, blood vessels, and bone. If this can be applied to human cells, it may eventually be possible to use hematopoietic stem cells to replace a wider array of cells and tissues than once thought.

Despite the vast experience with hematopoietic stem cells, scientists face major roadblocks in expanding their use beyond the replacement of blood and immune cells. First, hematopoietic stem cells are unable to proliferate (replicate themselves) and differentiate (become specialized to other cell types) in vitro (in the test tube or culture dish). Second, scientists do not yet have an accurate method to distinguish stem cells from other cells recovered from the blood or bone marrow. Until scientists overcome these technical barriers, they believe it is unlikely that hematopoietic stem cells will be applied as cell replacement therapy in diseases such as diabetes, Parkinson's Disease, spinal cord injury, and many others.

Blood cells are responsible for constant maintenance and immune protection of every cell type of the body. This relentless and brutal work requires that blood cells, along with skin cells, have the greatest powers of self-renewal of any adult tissue.

The stem cells that form blood and immune cells are known as hematopoietic stem cells (HSCs). They are ultimately responsible for the constant renewal of bloodthe production of billions of new blood cells each day. Physicians and basic researchers have known and capitalized on this fact for more than 50 years in treating many diseases. The first evidence and definition of blood-forming stem cells came from studies of people exposed to lethal doses of radiation in 1945.

Basic research soon followed. After duplicating radiation sickness in mice, scientists found they could rescue the mice from death with bone marrow transplants from healthy donor animals. In the early 1960s, Till and McCulloch began analyzing the bone marrow to find out which components were responsible for regenerating blood [56]. They defined what remain the two hallmarks of an HSC: it can renew itself and it can produce cells that give rise to all the different types of blood cells (see Chapter 4. The Adult Stem Cell).

A hematopoietic stem cell is a cell isolated from the blood or bone marrow that can renew itself, can differentiate to a variety of specialized cells, can mobilize out of the bone marrow into circulating blood, and can undergo programmed cell death, called apoptosisa process by which cells that are detrimental or unneeded self-destruct.

A major thrust of basic HSC research since the 1960s has been identifying and characterizing these stem cells. Because HSCs look and behave in culture like ordinary white blood cells, this has been a difficult challenge and this makes them difficult to identify by morphology (size and shape). Even today, scientists must rely on cell surface proteins, which serve, only roughly, as markers of white blood cells.

Identifying and characterizing properties of HSCs began with studies in mice, which laid the groundwork for human studies. The challenge is formidable as about 1 in every 10,000 to 15,000 bone marrow cells is thought to be a stem cell. In the blood stream the proportion falls to 1 in 100,000 blood cells. To this end, scientists began to develop tests for proving the self-renewal and the plasticity of HSCs.

The "gold standard" for proving that a cell derived from mouse bone marrow is indeed an HSC is still based on the same proof described above and used in mice many years ago. That is, the cells are injected into a mouse that has received a dose of irradiation sufficient to kill its own blood-producing cells. If the mouse recovers and all types of blood cells reappear (bearing a genetic marker from the donor animal), the transplanted cells are deemed to have included stem cells.

These studies have revealed that there appear to be two kinds of HSCs. If bone marrow cells from the transplanted mouse can, in turn, be transplanted to another lethally irradiated mouse and restore its hematopoietic system over some months, they are considered to be long-term stem cells that are capable of self-renewal. Other cells from bone marrow can immediately regenerate all the different types of blood cells, but under normal circumstances cannot renew themselves over the long term, and these are referred to as short-term progenitor or precursor cells. Progenitor or precursor cells are relatively immature cells that are precursors to a fully differentiated cell of the same tissue type. They are capable of proliferating, but they have a limited capacity to differentiate into more than one cell type as HSCs do. For example, a blood progenitor cell may only be able to make a red blood cell (see Figure 5.1. Hematopoietic and Stromal Stem Cell Differentiation ).

Figure 5.1. Hematopoietic and Stromal Stem Cell Differentiation.

( 2001 Terese Winslow, Lydia Kibiuk)

Harrison et al. write that short-term blood-progenitor cells in a mouse may restore hematopoiesis for three to four months [36]. The longevity of short-term stem cells for humans is not firmly established. A true stem cell, capable of self-renewal, must be able to renew itself for the entire lifespan of an organism. It is these long-term replicating HSCs that are most important for developing HSC-based cell therapies. Unfortunately, to date, researchers cannot distinguish the long-term from the short-term cells when they are removed from the bloodstream or bone marrow.

The central problem of the assays used to identify long-term stem cells and short-term progenitor cells is that they are difficult, expensive, and time-consuming and cannot be done in humans. A few assays are now available that test cells in culture for their ability to form primitive and long-lasting colonies of cells, but these tests are not accepted as proof that a cell is a long-term stem cell. Some genetically altered mice can receive transplanted human HSCs to test the cells' self-renewal and hematopoietic capabilities during the life of a mouse, but the relevance of this test for the cells in humanswho may live for decadesis open to question.

The difficulty of HSC assays has contributed to two mutually confounding research problems: definitively identifying the HSC and getting it to proliferate, or increase its numbers, in a culture dish. More rapid research progress on characterizing and using HSCs would be possible if they could be readily grown in the laboratory. Conversely, progress in identifying growth conditions suitable for HSCs and getting the cells to multiply would move more quickly if scientists could reliably and readily identify true HSCs.

HSCs have an identity problem. First, the ones with long-term replicating ability are rare. Second, there are multiple types of stem cells. And, third, the stem cells look like many other blood or bone marrow cells. So how do researchers find the desired cell populations? The most common approach is through markers that appear on the surface of cells. (For a more detailed discussion, see Appendix E.i. Markers: How Do Researchers Use Them to Identify Stem Cells?) These are useful, but not perfect tools for the research laboratory.

In 1988, in an effort to develop a reliable means of identifying these cells, Irving Weissman and his collaborators focused attention on a set of protein markers on the surface of mouse blood cells that were associated with increased likelihood that the cell was a long-term HSC [50]. Four years later, the laboratory proposed a comparable set of markers for the human stem cell [3]. Weissman proposes the markers shown in Table 5.1 as the closest markers for mouse and human HSCs [62].

* Only one of a family of CD59 markers has thus far been evaluated.** Lin- cells lack 13 to 14 different mature blood-lineage markers.

Such cell markers can be tagged with monoclonal antibodies bearing a fluorescent label and culled out of bone marrow with fluorescence-activated cell sorting (FACS).

The groups of cells thus sorted by surface markers are heterogeneous and include some cells that are true, long-term self-renewing stem cells, some shorter-term progenitors, and some non-stem cells. Weissman's group showed that as few as five genetically tagged cells, injected along with larger doses of stem cells into lethally irradiated mice, could establish themselves and produce marked donor cells in all blood cell lineages for the lifetime of the mouse. A single tagged cell could produce all lineages for as many as seven weeks, and 30 purified cells were sufficient to rescue mice and fully repopulate the bone marrow without extra doses of backup cells to rescue the mice [49]. Despite these efforts, researchers remain divided on the most consistently expressed set of HSC markers [27, 32]. Connie Eaves of the University of British Columbia says none of the markers are tied to unique stem cell functions or truly define the stem cell [14]. "Almost every marker I am aware of has been shown to be fickle," she says.

More recently, Diane Krause and her colleagues at Yale University, New York University, and Johns Hopkins University, used a new technique to home in on a single cell capable of reconstituting all blood cell lineages of an irradiated mouse [27]. After marking bone marrow cells from donor male mice with a nontoxic dye, they injected the cells into female recipient mice that had been given a lethal dose of radiation. Over the next two days, some of the injected cells migrated, or homed, to the bone marrow of the recipients and did not divide; when transplanted into a second set of irradiated female mice, they eventually proved to be a concentrated pool of self-renewing stem cells. The cells also reconstituted blood production. The scientists estimate that their technique concentrated the long-term stem cells 500 to 1,000- fold compared with bone marrow.

The classic source of hematopoietic stem cells (HSCs) is bone marrow. For more than 40 years, doctors performed bone marrow transplants by anesthetizing the stem cell donor, puncturing a bonetypically a hipboneand drawing out the bone marrow cells with a syringe. About 1 in every 100,000 cells in the marrow is a long-term, blood-forming stem cell; other cells present include stromal cells, stromal stem cells, blood progenitor cells, and mature and maturing white and red blood cells.

As a source of HSCs for medical treatments, bone marrow retrieval directly from bone is quickly fading into history. For clinical transplantation of human HSCs, doctors now prefer to harvest donor cells from peripheral, circulating blood. It has been known for decades that a small number of stem and progenitor cells circulate in the bloodstream, but in the past 10 years, researchers have found that they can coax the cells to migrate from marrow to blood in greater numbers by injecting the donor with a cytokine, such as granulocyte-colony stimulating factor (GCSF). The donor is injected with GCSF a few days before the cell harvest. To collect the cells, doctors insert an intravenous tube into the donor's vein and pass his blood through a filtering system that pulls out CD34+ white blood cells and returns the red blood cells to the donor. Of the cells collected, just 5 to 20 percent will be true HSCs. Thus, when medical researchers commonly refer to peripherally harvested "stem cells," this is something of a misnomer. As is true for bone marrow, the CD34+ cells are a mixture of stem cells, progenitors, and white blood cells of various degrees of maturity.

In the past three years, the majority of autologous (where the donor and recipient are the same person) and allogeneic (where the donor and recipient are different individuals) "bone marrow" transplants have actually been white blood cells drawn from peripheral circulation, not bone marrow. Richard Childs, an intramural investigator at the NIH, says peripheral harvest of cells is easier on the donorwith minimal pain, no anesthesia, and no hospital staybut also yields better cells for transplants [6]. Childs points to evidence that patients receiving peripherally harvested cells have higher survival rates than bone marrow recipients do. The peripherally harvested cells contain twice as many HSCs as stem cells taken from bone marrow and engraft more quickly. This means patients may recover white blood cells, platelets, and their immune and clotting protection several days faster than they would with a bone marrow graft. Scientists at Stanford report that highly purified, mobilized peripheral cells that have CD34+ and Thy-1+ surface markers engraft swiftly and without complication in breast cancer patients receiving an autologous transplant of the cells after intensive chemotherapy [41].

In the late 1980s and early 1990s, physicians began to recognize that blood from the human umbilical cord and placenta was a rich source of HSCs. This tissue supports the developing fetus during pregnancy, is delivered along with the baby, and, is usually discarded. Since the first successful umbilical cord blood transplants in children with Fanconi anemia, the collection and therapeutic use of these cells has grown quickly. The New York Blood Center's Placental Blood Program, supported by NIH, is the largest U.S. public umbilical cord blood bank and now has 13,000 donations available for transplantation into small patients who need HSCs. Since it began collecting umbilical cord blood in 1992, the center has provided thousands of cord blood units to patients. Umbilical cord blood recipientstypically childrenhave now lived in excess of eight years, relying on the HSCs from an umbilical cord blood transplant [31, 57].

There is a substantial amount of research being conducted on umbilical cord blood to search for ways to expand the number of HSCs and compare and contrast the biological properties of cord blood with adult bone marrow stem cells. There have been suggestions that umbilical cord blood contains stem cells that have the capability of developing cells of multiple germ layers (multipotent) or even all germ layers, e.g., endoderm, ectoderm, and mesoderm (pluripotent). To date, there is no published scientific evidence to support this claim. While umbilical cord blood represents a valuable resource for HSCs, research data have not conclusively shown qualitative differences in the differentiated cells produced between this source of HSCs and peripheral blood and bone marrow.

An important source of HSCs in research, but not in clinical use, is the developing blood-producing tissues of fetal animals. Hematopoietic cells appear early in the development of all vertebrates. Most extensively studied in the mouse, HSC production sweeps through the developing embryo and fetus in waves. Beginning at about day 7 in the life of the mouse embryo, the earliest hematopoietic activity is indicated by the appearance of blood islands in the yolk sac (see Appendix A. Early Development). The point is disputed, but some scientists contend that yolk sac blood production is transient and will generate some blood cells for the embryo, but probably not the bulk of the HSCs for the adult animal [12, 26, 44]. According to this proposed scenario, most stem cells that will be found in the adult bone marrow and circulation are derived from cells that appear slightly later and in a different location. This other wave of hematopoietic stem cell production occurs in the AGMthe region where the aorta, gonads, and fetal kidney (mesonephros) begin to develop. The cells that give rise to the HSCs in the AGM may also give rise to endothelial cells that line blood vessels. [13]. These HSCs arise at around days 10 to 11 in the mouse embryo (weeks 4 to 6 in human gestation), divide, and within a couple of days, migrate to the liver [11]. The HSCs in the liver continue to divide and migrate, spreading to the spleen, thymus, andnear the time of birthto the bone marrow.

Whereas an increasing body of fetal HSC research is emerging from mice and other animals, there is much less information about human fetal and embryonic HSCs. Scientists in Europe, including Coulombel, Peault, and colleagues, first described hematopoietic precursors in human embryos only a few years ago [20, 53]. Most recently, Gallacher and others reported finding HSCs circulating in the blood of 12- to 18-week aborted human fetuses [16, 28, 54] that was rich in HSCs. These circulating cells had different markers than did cells from fetal liver, fetal bone marrow, or umbilical cord blood.

In 1985, it was shown that it is possible to obtain precursors to many different blood cells from mouse embryonic stem cells [9]. Perkins was able to obtain all the major lineages of progenitor cells from mouse embryoid bodies, even without adding hematopoietic growth factors [45].

Mouse embryonic stem cells in culture, given the right growth factors, can generate most, if not all, the different blood cell types [19], but no one has yet achieved the "gold standard" of proof that they can produce long-term HSCs from these sourcesnamely by obtaining cells that can be transplanted into lethally irradiated mice to reconstitute long-term hematopoiesis [32].

The picture for human embryonic stem and germ cells is even less clear. Scientists from James Thomson's laboratory reported in 1999 that they were able to direct human embryonic stem cellswhich can now be cultured in the labto produce blood progenitor cells [23]. Israeli scientists reported that they had induced human ES cells to produce hematopoietic cells, as evidenced by their production of a blood protein, gamma-globin [21]. Cell lines derived from human embryonic germ cells (cultured cells derived originally from cells in the embryo that would ultimately give rise to eggs or sperm) that are cultured under certain conditions will produce CD34+ cells [47]. The blood-producing cells derived from human ES and embryonic germ (EG) cells have not been rigorously tested for long-term self-renewal or the ability to give rise to all the different blood cells.

As sketchy as data may be on the hematopoietic powers of human ES and EG cells, blood experts are intrigued by their clinical potential and their potential to answer basic questions on renewal and differentiation of HSCs [19]. Connie Eaves, who has made comparisons of HSCs from fetal liver, cord blood, and adult bone marrow, expects cells derived from embryonic tissues to have some interesting traits. She says actively dividing blood-producing cells from ES cell cultureif they are like other dividing cellswill not themselves engraft or rescue hematopoiesis in an animal whose bone marrow has been destroyed. However, they may play a critical role in developing an abundant supply of HSCs grown in the lab. Indications are that the dividing cells will also more readily lend themselves to gene manipulations than do adult HSCs. Eaves anticipates that HSCs derived from early embryo sources will be developmentally more "plastic" than later HSCs, and more capable of self-renewal [14].

Scientists in the laboratory and clinic are beginning to measure the differences among HSCs from different sources. In general, they find that HSCs taken from tissues at earlier developmental stages have a greater ability to self-replicate, show different homing and surface characteristics, and are less likely to be rejected by the immune systemmaking them potentially more useful for therapeutic transplantation.

When do HSCs move from the early locations in the developing fetus to their adult "home" in the bone marrow? European scientists have found that the relative number of CD34+ cells in the collections of cord blood declined with gestational age, but expression of cell-adhesion molecules on these cells increased.

The authors believe these changes reflect preparations for the cells to relocatefrom homing in fetal liver to homing in bone marrow [52].

The point is controversial, but a paper by Chen et al. provides evidence that at least in some strains of mice, HSCs from old mice are less able to repopulate bone marrow after transplantation than are cells from young adult mice [5]. Cells from fetal mice were 50 to 100 percent better at repopulating marrow than were cells from young adult mice were. The specific potential for repopulating marrow appears to be strain-specific, but the scientists found this potential declined with age for both strains. Other scientists find no decreases or sometimes increases in numbers of HSCs with age [51]. Because of the difficulty in identifying a long-term stem cell, it remains difficult to quantify changes in numbers of HSCs as a person ages.

A practical and important difference between HSCs collected from adult human donors and from umbilical cord blood is simply quantitative. Doctors are rarely able to extract more than a few million HSCs from a placenta and umbilical cordtoo few to use in a transplant for an adult, who would ideally get 7 to 10 million CD34+ cells per kilogram body weight, but often adequate for a transplant for a child [33, 48].

Leonard Zon says that HSCs from cord blood are less likely to cause a transplantation complication called graft-versus-host disease, in which white blood cells from a donor attack tissues of the recipient [65]. In a recent review of umbilical cord blood transplantation, Laughlin cites evidence that cord blood causes less graft-versus-host disease [31]. Laughlin writes that it is yet to be determined whether umbilical cord blood HSCs are, in fact, longer lived in a transplant recipient.

In lab and mouse-model tests comparing CD34+ cells from human cord with CD34+ cells derived from adult bone marrow, researchers found cord blood had greater proliferation capacity [24]. White blood cells from cord blood engrafted better in a mouse model, which was genetically altered to tolerate the human cells, than did their adult counterparts.

In addition to being far easier to collect, peripherally harvested white blood cells have other advantages over bone marrow. Cutler and Antin's review says that peripherally harvested cells engraft more quickly, but are more likely to cause graft-versus-host disease [8]. Prospecting for the most receptive HSCs for gene therapy, Orlic and colleagues found that mouse HSCs mobilized with cytokines were more likely to take up genes from a viral vector than were non-mobilized bone marrow HSCs [43].

As stated earlier, an HSC in the bone marrow has four actions in its repertoire: 1) it can renew itself, 2) it can differentiate, 3) it can mobilize out of the bone marrow into circulation (or the reverse), or 4) it can undergo programmed cell death, or apoptosis. Understanding the how, when, where, which, and why of this simple repertoire will allow researchers to manipulate and use HSCs for tissue and organ repair.

Scientists have had a tough time trying to growor even maintaintrue stem cells in culture. This is an important goal because cultures of HSCs that could maintain their characteristic properties of self-renewal and lack of differentiation could provide an unlimited source of cells for therapeutic transplantation and study. When bone marrow or blood cells are observed in culture, one often observes large increases in the number of cells. This usually reflects an increase in differentiation of cells to progenitor cells that can give rise to different lineages of blood cells but cannot renew themselves. True stem cells divide and replace themselves slowly in adult bone marrow.

New tools for gene-expression analysis will now allow scientists to study developmental changes in telomerase activity and telomeres. Telomeres are regions of DNA found at the end of chromosomes that are extended by the enzyme telomerase. Telomerase activity is necessary for cells to proliferate and activity decreases with age leading to shortened telomeres. Scientists hypothesize that declines in stem cell renewal will be associated with declines in telomere length and telomerase activity. Telomerase activity in hematopoietic cells is associated with self-renewal potential [40].

Because self-renewal divisions are rare, hard to induce in culture, and difficult to prove, scientists do not have a definitive answer to the burning question: what putsor perhaps keepsHSCs in a self-renewal division mode? HSCs injected into an anemic patient or mouseor one whose HSCs have otherwise been suppressed or killedwill home to the bone marrow and undergo active division to both replenish all the different types of blood cells and yield additional self-renewing HSCs. But exactly how this happens remains a mystery that scientists are struggling to solve by manipulating cultures of HSCs in the laboratory.

Two recent examples of progress in the culturing studies of mouse HSCs are by Ema and coworkers and Audet and colleagues [2, 15]. Ema et al. found that two cytokinesstem cell factor and thrombo-poietinefficiently induced an unequal first cell division in which one daughter cell gave rise to repopulating cells with self-renewal potential. Audet et al. found that activation of the signaling molecule gp130 is critical to survival and proliferation of mouse HSCs in culture.

Work with specific cytokines and signaling molecules builds on several earlier studies demonstrating modest increases in the numbers of stem cells that could be induced briefly in culture. For example, Van Zant and colleagues used continuous-perfusion culture and bioreactors in an attempt to boost human HSC numbers in single cord blood samples incubated for one to two weeks [58]. They obtained a 20-fold increase in "long-term culture initiating cells."

More clues on how to increase numbers of stem cells may come from looking at other animals and various developmental stages. During early developmental stagesin the fetal liver, for exampleHSCs may undergo more active cell division to increase their numbers, but later in life, they divide far less often [30, 42]. Culturing HSCs from 10- and 11-day-old mouse embryos, Elaine Dzierzak at Erasmus University in the Netherlands finds she can get a 15-fold increase in HSCs within the first 2 or 3 days after she removes the AGM from the embryos [38]. Dzierzak recognizes that this is dramatically different from anything seen with adult stem cells and suggests it is a difference with practical importance. She suspects that the increase is not so much a response to what is going on in the culture but rather, it represents the developmental momentum of this specific embryonic tissue. That is, it is the inevitable consequence of divisions that were cued by that specific embryonic microenvironment. After five days, the number of HSCs plateaus and can be maintained for up to a month. Dzierzak says that the key to understanding how adult-derived HSCs can be expanded and manipulated for clinical purposes may very well be found by defining the cellular composition and complex molecular signals in the AGM region during development [13].

In another approach, Lemischka and coworkers have been able to maintain mouse HSCs for four to seven weeks when they are grown on a clonal line of cells (AFT024) derived from the stroma, the other major cellular constituent of bone marrow [39]. No one knows which specific factors secreted by the stromal cells maintain the stem cells. He says ongoing gene cloning is rapidly zeroing in on novel molecules from the stromal cells that may "talk" to the stem cells and persuade them to remain stem cellsthat is, continue to divide and not differentiate.

If stromal factors provide the key to stem cell self-renewal, research on maintaining stromal cells may be an important prerequisite. In 1999, researchers at Osiris Therapeutics and Johns Hopkins University reported culturing and expanding the numbers of mesenchymal stem cells, which produce the stromal environment [46]. Whereas cultured HSCs rush to differentiate and fail to retain primitive, self-renewing cells, the mesenchymal stem cells could be increased in numbers and still retained their powers to generate the full repertoire of descendant lineages.

Producing differentiated white and red blood cells is the real work of HSCs and progenitor cells. M.C. MacKey calculates that in the course of producing a mature, circulating blood cell, the original hematopoietic stem cell will undergo between 17 and 19.5 divisions, "giving a net amplification of between ~170,000 and ~720,000" [35].

Through a series of careful studies of cultured cellsoften cells with mutations found in leukemia patients or cells that have been genetically alteredinvestigators have discovered many key growth factors and cytokines that induce progenitor cells to make different types of blood cells. These factors interact with one another in complex ways to create a system of exquisite genetic control and coordination of blood cell production.

Scientists know that much of the time, HSCs live in intimate connection with the stroma of bone marrow in adults (see Chapter 4. The Adult Stem Cell). But HSCs may also be found in the spleen, in peripheral blood circulation, and other tissues. Connection to the interstices of bone marrow is important to both the engraftment of transplanted cells and to the maintenance of stem cells as a self-renewing population. Connection to stroma is also important to the orderly proliferation, differentiation, and maturation of blood cells [63].

Weissman says HSCs appear to make brief forays out of the marrow into tissues, then duck back into marrow [62]. At this time, scientists do not understand why or how HSCs leave bone marrow or return to it [59]. Scientists find that HSCs that have been mobilized into peripheral circulation are mostly non-dividing cells [64]. They report that adhesion molecules on the stroma, play a role in mobilization, in attachment to the stroma, and in transmitting signals that regulate HSC self-renewal and progenitor differentiation [61].

The number of blood cells in the bone marrow and blood is regulated by genetic and molecular mechanisms. How do hematopoietic stem cells know when to stop proliferating? Apoptosis is the process of programmed cell death that leads cells to self-destruct when they are unneeded or detrimental. If there are too few HSCs in the body, more cells divide and boost the numbers. If excess stem cells were injected into an animal, they simply wouldn't divide or would undergo apoptosis and be eliminated [62]. Excess numbers of stem cells in an HSC transplant actually seem to improve the likelihood and speed of engraftment, though there seems to be no rigorous identification of a mechanism for this empirical observation.

The particular signals that trigger apoptosis in HSCs are as yet unknown. One possible signal for apoptosis might be the absence of life-sustaining signals from bone marrow stroma. Michael Wang and others found that when they used antibodies to disrupt the adhesion of HSCs to the stroma via VLA-4/VCAM-1, the cells were predisposed to apoptosis [61].

Understanding the forces at play in HSC apoptosis is important to maintaining or increasing their numbers in culture. For example, without growth factors, supplied in the medium or through serum or other feeder layers of cells, HSCs undergo apoptosis. Domen and Weissman found that stem cells need to get two growth factor signals to continue life and avoid apoptosis: one via a protein called BCL-2, the other from steel factor, which, by itself, induces HSCs to produce progenitor cells but not to self-renew [10].

Among the first clinical uses of HSCs were the treatment of cancers of the bloodleukemia and lymphoma, which result from the uncontrolled proliferation of white blood cells. In these applications, the patient's own cancerous hematopoietic cells were destroyed via radiation or chemotherapy, then replaced with a bone marrow transplant, or, as is done now, with a transplant of HSCs collected from the peripheral circulation of a matched donor. A matched donor is typically a sister or brother of the patient who has inherited similar human leukocyte antigens (HLAs) on the surface of their cells. Cancers of the blood include acute lymphoblastic leukemia, acute myeloblastic leukemia, chronic myelogenous leukemia (CML), Hodgkin's disease, multiple myeloma, and non-Hodgkin's lymphoma.

Thomas and Clift describe the history of treatment for chronic myeloid leukemia as it moved from largely ineffective chemotherapy to modestly successful use of a cytokine, interferon, to bone marrow trans-plantsfirst in identical twins, then in HLA-matched siblings [55]. Although there was significant risk of patient death soon after the transplant either from infection or from graft-versus-host disease, for the first time, many patients survived this immediate challenge and had survival times measured in years or even decades, rather than months. The authors write, "In the space of 20 years, marrow transplantation has contributed to the transformation of [chronic myelogenous leukemia] CML from a fatal disease to one that is frequently curable. At the same time, experience acquired in this setting has improved our understanding of many transplant-related problems. It is now clear that morbidity and mortality are not inevitable consequences of allogeneic transplantation, [and] that an allogeneic effect can add to the anti-leukemic power of conditioning regimens"

In a recent development, CML researchers have taken their knowledge of hematopoietic regulation one step farther. On May 10, 2001, the Food and Drug Administration approved Gleevec (imatinib mesylate), a new, rationally designed oral drug for treatment of CML. The new drug specifically targets a mutant protein, produced in CML cancer cells, that sabotages the cell signals controlling orderly division of progenitor cells. By silencing this protein, the new drug turns off cancerous overproduction of white blood cells, so doctors do not have to resort to bone marrow transplantation. At this time, it is unknown whether the new drug will provide sustained remission or will prolong life for CML patients.

Another use of allogeneic bone marrow transplants is in the treatment of hereditary blood disorders, such as different types of inherited anemia (failure to produce blood cells), and inborn errors of metabolism (genetic disorders characterized by defects in key enzymes need to produce essential body components or degrade chemical byproducts). The blood disorders include aplastic anemia, beta-thalassemia, Blackfan-Diamond syndrome, globoid cell leukodystrophy, sickle-cell anemia, severe combined immunodeficiency, X-linked lymphoproliferative syndrome, and Wiskott-Aldrich syndrome. Inborn errors of metabolism that are treated with bone marrow transplants include: Hunter's syndrome, Hurler's syndrome, Lesch Nyhan syndrome, and osteopetrosis. Because bone marrow transplantation has carried a significant risk of death, this is usually a treatment of last resort for otherwise fatal diseases.

Chemotherapy aimed at rapidly dividing cancer cells inevitably hits another targetrapidly dividing hematopoietic cells. Doctors may give cancer patients an autologous stem cell transplant to replace the cells destroyed by chemotherapy. They do this by mobilizing HSCs and collecting them from peripheral blood. The cells are stored while the patient undergoes intensive chemotherapy or radiotherapy to destroy the cancer cells. Once the drugs have washed out of a patient's body, the patient receives a transfusion of his or her stored HSCs. Because patients get their own cells back, there is no chance of immune mismatch or graft-versus-host disease. One problem with the use of autologous HSC transplants in cancer therapy has been that cancer cells are sometimes inadvertently collected and reinfused back into the patient along with the stem cells. One team of investigators finds that they can prevent reintroducing cancer cells by purifying the cells and preserving only the cells that are CD34+, Thy-1+[41].

One of the most exciting new uses of HSC transplantation puts the cells to work attacking otherwise untreatable tumors. A group of researchers in NIH's intramural research program recently described this approach to treating metastatic kidney cancer [7]. Just under half of the 38 patients treated so far have had their tumors reduced. The research protocol is now expanding to treatment of other solid tumors that resist standard therapy, including cancer of the lung, prostate, ovary, colon, esophagus, liver, and pancreas.

This experimental treatment relies on an allogeneic stem cell transplant from an HLA-matched sibling whose HSCs are collected peripherally. The patient's own immune system is suppressed, but not totally destroyed. The donor's cells are transfused into the patient, and for the next three months, doctors closely monitor the patient's immune cells, using DNA fingerprinting to follow the engraftment of the donor's cells and regrowth of the patient's own blood cells. They must also judiciously suppress the patient's immune system as needed to deter his/her T cells from attacking the graft and to reduce graft-versus-host disease.

A study by Joshi et al. shows that umbilical cord blood and peripherally harvested human HSCs show antitumor activity in the test tube against leukemia cells and breast cancer cells [22]. Grafted into a mouse model that tolerates human cells, HSCs attack human leukemia and breast cancer cells. Although untreated cord blood lacks natural killer (NK) lymphocytes capable of killing tumor cells, researchers have found that at least in the test tube and in mice, they can greatly enhance the activity and numbers of these cells with cytokines IL-15 [22, 34].

Substantial basic and limited clinical research exploring the experimental uses of HSCs for other diseases is underway. Among the primary applications are autoimmune diseases, such as diabetes, rheumatoid arthritis, and system lupus erythematosis. Here, the body's immune system turns to destroying body tissues. Experimental approaches similar to those applied above for cancer therapies are being conducted to see if the immune system can be reconstituted or reprogrammed. More detailed discussion on this application is provided in Chapter 6. Autoimmune Diseases and the Promise of Stem Cell-Based Therapies. The use of HSCs as a means to deliver genes to repair damaged cells is another application being explored. The use of HSCs for gene therapies is discussed in detail in Chapter 11. Use of Genetically Modified Stem Cells in Experimental Gene Therapies.

A few recent reports indicate that scientists have been able to induce bone marrow or HSCs to differentiate into other types of tissue, such as brain, muscle, and liver cells. These concepts and the experimental evidence supporting this concept are discussed in Chapter 4. The Adult Stem Cell.

Research in a mouse model indicates that cells from grafts of bone marrow or selected HSCs may home to damaged skeletal and cardiac muscle or liver and regenerate those tissues [4, 29]. One recent advance has been in the study of muscular dystrophy, a genetic disease that occurs in young people and leads to progressive weakness of the skeletal muscles. Bittner and colleagues used mdx mice, a genetically modified mouse with muscle cell defects similar to those in human muscular dystrophy. Bone marrow from non-mdx male mice was transplanted into female mdx mice with chronic muscle damage; after 70 days, researchers found that nuclei from the males had taken up residence in skeletal and cardiac muscle cells.

Lagasse and colleagues' demonstration of liver repair by purified HSCs is a similarly encouraging sign that HSCs may have the potential to integrate into and grow in some non-blood tissues. These scientists lethally irradiated female mice that had an unusual genetic liver disease that could be halted with a drug. The mice were given transplants of genetically marked, purified HSCs from male mice that did not have the liver disease. The transplants were given a chance to engraft for a couple of months while the mice were on the liver-protective drug. The drug was then removed, launching deterioration of the liverand a test to see whether cells from the transplant would be recruited and rescue the liver. The scientists found that transplants of as few as 50 cells led to abundant growth of marked, donor-derived liver cells in the female mice.

Recently, Krause has shown in mice that a single selected donor hematopoietic stem cell could do more than just repopulate the marrow and hematopoietic system of the recipient [27]. These investigators also found epithelial cells derived from the donors in the lungs, gut, and skin of the recipient mice. This suggests that HSCs may have grown in the other tissues in response to infection or damage from the irradiation the mice received.

In humans, observations of male liver cells in female patients who have received bone marrow grafts from males, and in male patients who have received liver transplants from female donors, also suggest the possibility that some cells in bone marrow have the capacity to integrate into the liver and form hepatocytes [1].

Clinical investigators share the same fundamental problem as basic investigatorslimited ability to grow and expand the numbers of human HSCs. Clinicians repeatedly see that larger numbers of cells in stem cell grafts have a better chance of survival in a patient than do smaller numbers of cells. The limited number of cells available from a placenta and umbilical cord blood transplant currently means that cord blood banks are useful to pediatric but not adult patients. Investigators believe that the main cause of failure of HSCs to engraft is host-versus-graft disease, and larger grafts permit at least some donor cells to escape initial waves of attack from a patient's residual or suppressed immune system [6]. Ability to expand numbers of human HSCs in vivo or in vitro would clearly be an enormous boost to all current and future medical uses of HSC transplantation.

Once stem cells and their progeny can be multiplied in culture, gene therapists and blood experts could combine their talents to grow limitless quantities of "universal donor" stem cells, as well as progenitors and specific types of red and white blood cells. If the cells were engineered to be free of markers that provoke rejection, these could be transfused to any recipient to treat any of the diseases that are now addressed with marrow, peripheral, cord, or other transfused blood. If gene therapy and studies of the plasticity of HSCs succeed, the cells could also be grown to repair other tissues and treat non-blood-related disorders [32].

Several research groups in the United States, Canada, and abroad have been striving to find the key factor or factors for boosting HSC production. Typical approaches include comparing genes expressed in primitive HSCs versus progenitor cells; comparing genes in actively dividing fetal HSCs versus adult HSCs; genetic screening of hematopoietically mutated zebrafish; studying dysregulated genes in cancerous hematopoietic cells; analyzing stromal or feeder-layer factors that appear to boost HSC division; and analyzing factors promoting homing and attachment to the stroma. Promising candidate factors have been tried singly and in combination, and researchers claim they can now increase the number of long-term stem cells 20-fold, albeit briefly, in culture.

The specific assays researchers use to prove that their expanded cells are stem cells vary, which makes it difficult to compare the claims of different research groups. To date, there is only a modest ability to expand true, long-term, self-renewing human HSCs. Numbers of progenitor cells are, however, more readily increased. Kobari et al., for example, can increase progenitor cells for granulocytes and macrophages 278-fold in culture [25].

Some investigators are now evaluating whether these comparatively modest increases in HSCs are clinically useful. At this time, the increases in cell numbers are not sustainable over periods beyond a few months, and the yield is far too low for mass production. In addition, the cells produced are often not rigorously characterized. A host of other questions remainfrom how well the multiplied cells can be altered for gene therapy to their potential longevity, immunogenicity, ability to home correctly, and susceptibility to cancerous transformation. Glimm et al. [17] highlight some of these problems, for example, with their confirmation that human stem cells lose their ability to repopulate the bone marrow as they enter and progress through the cell cyclelike mouse stem cells that have been stimulated to divide lose their transplantability [18]. Observations on the inverse relationship between progenitor cell division rate and longevity in strains of mice raise an additional concern that culture tricks or selection of cells that expand rapidly may doom the cells to a short life.

Pragmatically, some scientists say it may not be necessary to be able to induce the true, long-term HSC to divide in the lab. If they can manipulate progenitors and coax them into division on command, gene uptake, and differentiation into key blood cells and other tissues, that may be sufficient to accomplish clinical goals. It might be sufficient to boost HSCs or subpopulations of hematopoietic cells within the body by chemically prodding the bone marrow to supply the as-yet-elusive factors to rejuvenate cell division.

Currently, the risks of bone marrow transplantsgraft rejection, host-versus-graft disease, and infection during the period before HSCs have engrafted and resumed full blood cell productionrestrict their use to patients with serious or fatal illnesses. Allogeneic grafts must come from donors with a close HLA match to the patient (see Chapter 6. Autoimmune Diseases and the Promise of Stem Cell-Based Therapies). If doctors could precisely manipulate immune reactions and protect patients from pathogens before their transplants begin to function, HSC transplants could be extended to less ill patients and patients for whom the HLA match was not as close as it must now be. Physicians might use transplants with greater impunity in gene therapy, autoimmune disease, HIV/AIDS treatment, and the preconditioning of patients to accept a major organ transplant.

Scientists are zeroing in on subpopulations of T cells that may cause or suppress potentially lethal host-versus-graft rejection and graft-versus-host disease in allogeneic-transplant recipients. T cells in a graft are a two-edged sword. They fight infections and help the graft become established, but they also can cause graft-versus-host disease. Identifying subpopulations of T cells responsible for deleterious and beneficial effectsin the graft, but also in residual cells surviving or returning in the hostcould allow clinicians to make grafts safer and to ratchet up graft-versus-tumor effects [48]. Understanding the presentation of antigens to the immune system and the immune system's healthy and unhealthy responses to these antigens and maturation and programmed cell death of T cells is crucial.

The approach taken by investigators at Stanfordpurifying peripheral bloodmay also help eliminate the cells causing graft-versus-host disease. Transplants in mouse models support the idea that purified HSCs, cleansed of mature lymphocytes, engraft readily and avoid graft-versus-host disease [60].

Knowledge of the key cellular actors in autoimmune disease, immune grafting, and graft rejection could also permit scientists to design gentler "minitransplants." Rather than obliterating and replacing the patient's entire hematopoietic system, they could replace just the faulty components with a selection of cells custom tailored to the patient's needs. Clinicians are currently experimenting with deletion of T cells from transplants in some diseases, for example, thereby reducing graft-versus-host disease.

Researchers are also experimenting with the possibility of knocking down the patient's immune systembut not knocking it out. A blow that is sublethal to the patient's hematopoietic cells given before an allogeneic transplant can be enough to give the graft a chance to take up residence in the bone marrow. The cells replace some or all of the patient's original stem cells, often making their blood a mix of donor and original cells. For some patients, this mix of cells will be enough to accomplish treatment objectives but without subjecting them to the vicious side effects and infection hazards of the most powerful treatments used for total destruction of their hematopoietic systems [37].

At some point in embryonic development, all cells are plastic, or developmentally flexible enough to grow into a variety of different tissues. Exactly what is it about the cell or the embryonic environment that instructs cells to grow into one organ and not another?

Could there be embryological underpinnings to the apparent plasticity of adult cells? Researchers have suggested that a lot of the tissues that are showing plasticity are adjacent to one another after gastrulation in the sheet of mesodermal tissue that will go on to form bloodmuscle, blood vessels, kidney, mesenchyme, and notochord. Plasticity may reflect derivation from the mesoderm, rather than being a fixed trait of hematopoietic cells. One lab is now studying the adjacency of embryonic cells and how the developing embryo makes the decision to make one tissue instead of anotherand whether the decision is reversible [65].

In vivo studies of the plasticity of bone marrow or purified stem cells injected into mice are in their infancy. Even if follow-up studies confirm and more precisely characterize and quantify plasticity potential of HSCs in mice, there is no guarantee that it will occur or can be induced in humans.

Grounded in half a century of research, the study of hematopoietic stem cells is one of the most exciting and rapidly advancing disciplines in biomedicine today. Breakthrough discoveries in both the laboratory and clinic have sharply expanded the use and supply of life-saving stem cells. Yet even more promising applications are on the horizon and scientists' current inability to grow HSCs outside the body could delay or thwart progress with these new therapies. New treatments include graft-versus-tumor therapy for currently incurable cancers, autologous transplants for autoimmune diseases, and gene therapy and tissue repair for a host of other problems. The techniques, cells, and knowledge that researchers have now are inadequate to realize the full promise of HSC-based therapy.

Key issues for tapping the potential of hematopoietic stem cells will be finding ways to safely and efficiently expand the numbers of transplantable human HSCs in vitro or in vivo. It will also be important to gain a better understanding of the fundamentals of how immune cells workin fighting infections, in causing transplant rejection, and in graft-versus-host disease as well as master the basics of HSC differentiation. Concomitant advances in gene therapy techniques and the understanding of cellular plasticity could make HSCs one of the most powerful tools for healing.

Chapter 4|Table of Contents|Chapter 6

Historical content: June 17, 2001

Continued here:
5. Hematopoietic Stem Cells | stemcells.nih.gov

ByMarielle Segarra

August 29, 2017 | 11:35 AM

The Food and Drug Administration announced that it plans to crack down on health clinics that it says are providing unproven, unsafe stem cell treatments.

Stem cells help repair injured tissues in the human body. They can divide and then morph into other kinds of cells red blood cells, muscle cells, whatever our bodies need. Scientists have been trying to figure out whether they can use stem cell injections to treat certain diseases, but for the most part, theres not enough evidence yet that these treatments are safe or that they work.

Nearly600 clinics around the U.S., many in California and Florida, market stem cell treatments, according to a study published last year in the peer-reviewed scientific journal Cell Stem Cell.

Some clinics claim to use stem cells to treat diseases like amyotrophic lateral sclerosis (Lou Gehrig's disease), Alzheimers disease, and Parkinsons disease. Others offer procedures they say can roll back the effects of aging, like stem cell face-lifts.

"You can just find hundreds of businesses making these unsubstantiated marketing claims," said Leigh Turner, the study's co-author and associate professor at the University of Minnesota's Center for Bioethics, "and that's where you run into a lot of problems in terms of the risk that people are spending thousands or tens of thousands of dollars and effectively being defrauded."

These treatments can also be dangerous, Turner said; in some patients, theyve caused blindness, tumors and even death.

Stem cell treatments are regulated by the FDA, but federal lawleaves some wiggle room. If a clinic meets a few requirements, like only manipulating cells in certain ways before injecting them, it doesnt have to get FDA approval. A lot of providers say they're exempt under this provision, and in some cases, that's not true.

Yesterday, the agency said it would step up enforcement on clinics that are breaking the law. This fall, it also plans to release new guidelines to make it clearer which treatments have to get approval and what the process entails.

Go here to see the original:
FDA to crack down on clinics illegally offering stem cell treatments - Marketplace.org

This is not about creating zombies-those so-called living (or walking) dead that are very popular and make a really great theme for TV shows and movies.

Even the Game of Thrones has its version of the living dead with them nasty creatures called White Walkers and Wights.

But then again, thats only science fiction, isnt it? Well, maybe not. In fact, this science-fiction plot could soon play out in real life. Read on.

Researchers from U.S.-based biotech company Bioquark are aimimg to resurrect patients who have been declared brain dead. Yep, you read it right. Resurrect, just like those stories in the Bible. Really bringing back people to life.

It goes without saying that this is really a serious matter. More importantly, Bioquarks small pilot study has been approved and gotten ethical permission by none other than the National Institutes of Health. The study would be an attempt to reawaken the clinically-dead brains of patients who have suffered serious brain injuries.

How will Bioquark do it?

Through stem cell therapy, which has been proven successful already in treating various diseases such as acquired ataxia, Alzheimers disease, Bells Palsy, cerebral atrophy, cirrhosis, optic nerve damage, osteoarthritis, and leukemia.

But, with brain-dead people, its going to be a real challenge since this condition according to medical experts is irreversible.

Brain death is different from a heart thats already stopped beating. A heart can still be revived and sustained by a ventilator or life-support system.

However, in the case of brain death, you cannot revive dead neurons with the help of a life-support machine even though it continues to pump oxygen to the body. The oxygen will get into the other organs like the heart, but it can no longer be utilized by the brain when the neurons are dead.

Neurons are the working units of the brain, specialized cells which are responsible for transmitting information to other nerve cells, gland cells, and muscles.They form networks or connections in the brain which number up to trillions.

A traumatic brain injury, sudden cardiac arrest, or a stroke caused by a ruptured blood vessel in the brain can cause brain tissues to start dying due to oxygen deprivation.

Oxygen-Deprived Brains Timeline:

However, Bioquark is hopeful that stem cell treatment may spur the growth of new neurons to replace the dead ones and pave the way to revive a clinically dead brain. After all, the brain is a fighter and scientists have found out that our gray matter has a small reservoir of stem cells which can produce new neurons.

Researchers are thinking of the possibility of urging these stem cells to generate new neurons which can remedy injured brain tissues. One other option is to inject neural stem cells into the brain of a person who has just died, and these may generate the necessary new neurons to help revive the brain.

Soon, Bioquark will find out the answer or learn some more information from their pilot study which is the first stage of the companys broaderReanima project. The project is exploring the potential of cutting edge biomedical technology for human neuro-regeneration and neuro-reanimation as a way to hopefully give patients and their loved ones a second chance in life.

Bioquark is set to conduct this very first human trial in partnership with the Indian biotech company Revita Life Sciences which specializes in stem cell treatment.

Excerpt from:
Brain Dead Patients Could Be Brought 'Back to Life' in Groundbreaking Stem Cell Therapy - Wall Street Pit

According to Biocentrism, death is not the end of the journey, but a journey.

Life goes on in a parallel universe regardless of what happens to it in this one.

Now he has departed from this strange world a little ahead of me. Wrote Einstein in a condolence letter upon the death of his close friend, Michele Besso, in 1955. That signifies nothing. For those of us who believe in physics, the distinction between past, present, and future is only a stubbornly persistent illusion.

Einstein died merely a month after he wrote the letter and, apparently, he was right, as new scientific theories suggest that death, just like life, is but an illusion.

Quantum physics laws tells us that life is not made of matter but of vibrations that escape time and space.

What happens when we die? Where does the human conscience come from? Does the brain perceive or create (then perceive) what we call reality? If consciousness doesnt originate from the brain, then the presence of physical envelopes isnt crucial for it to exist.

I regard consciousness as fundamental. I regard matter as derivative from consciousness. Said Max Planck, Nobel Prize-winning physicist, We cannot get behind consciousness. Everything that we talk about, everything that we regard as existing, postulates consciousness.

Biocentrism builds on that and goes on to suggest that consciousness creates the universe or reality, that time and space are mere illusions, manifestations in our minds, and that reality is determined by the observer.

Biocentrism and Relativity predict the same phenomena, but biocentrism, according to its fans, is superior because it does not need to imagine an extra dimension or new mathematics to be formulated.

Biocentrism claims that life is immortal and that its at the center of existence, reality, and the cosmos. By adding life and consciousness to the equation, biocentrism is believed by its adepts to be the theory of everything.

Robert Lanza is a highly qualified scientist and a priori a very serious person. Hes specialized in stem cells, cloning, and regenerative medicine research. Lanza has a distinguished career with articles devoted to him in prestigious publications.

In 2014, he made the Time Magazines list of the 100 most influential people in the world, and in 2015, Prospect Magazine selected him as one of the Worlds Thinkers 2015.

In 2009, Lanza published his book BIOCENTRISM: How Life and Consciousness are the Keys to Understanding the True Nature of the Universe in which he places biology above other sciences and calls for a switch from physics to biology to understand everything.

Dr. Lanza says that he thinks he is succeeding in the unification that Einstein would have failed to achieve, claiming that Einstein only considered reality from the physical side, without giving much thought to biology.

Lanza claims that quantum physics has proved the existence of life after death, that energy is immortal, and so is life.

For Lanza, we believe in death because we have been taught that we are dying, however, biocentrism says the universe exists only because the individual is aware of it.

Life and biology create this reality, and the universe itself does not create life. The concepts of time and space, according to Lanza, are simply tools of our imagination.

Last year, Lanza, along with astronomer Bob Berman, revisited his controversial theory in a new book, Beyond Biocentrism.

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There is Life After Death According to Quantum Physics - Edgy Labs (blog)

In the nearly five years Howell Brown III was in Durham for cancer treatments, he touched the lives of many including those in Dukes and N.C. Centrals athletics departments.

Howell, a huge NASCAR fan who loved playing with John Deere tractors, was just 9 when he was diagnosed with Stage IV Pineoblastoma. According to St. Judes Childrens Research Hopsitals website, Pineoblastoma is an aggressive and rare type of tumor of the brains pineal gland, a tiny organ located deep inside the brain that secretes ... a hormone called melatonin, which controls sleep.

In November 2012, Howells mother, Sue, brought him from Asheville to Duke Childrens Hospital for treatments. He had surgeries, chemotherapy, radiation and an infusion with his own stem cells. Along the way, walking and eating disorders complicated his condition. In 2015, he learned the cancer had spread to his spine.

Howell died Friday at age 13.

Throughout his illness, Howell became a source of encouragement for others and touched athletes and coaches at Duke and N.C. Central.

Dont give up. Just keep fighting through it even if you dont feel like doing it... Howell said the day he signed a football scholarship with N.C. Central. Youre going to go over the waves and the waves, and youre going to eventually hit the smooth part.

Duke football coach David Cutcliffe and his players met Howell during visits to Duke Childrens Hospital in 2013. Cutcliffe invited him to practices and to hang out with the team.

Duke football coach David Cutcliffe visits with 13-year-old Howell Brown during a team practice session last February. Brown died after a five-year battle with cancer on Friday.

Duke Athletics

In 2014, working in conjuction with Team IMPACT, a Boston company that connects seriously ill children with college sports teams, Howell spent the football season attending N.C. Centrals practices, games and social events.

That same year, during a time Howell was declared tumor-free, he signed a mock football scholarship with the Eagles and attended a press conference to celebrate the event. He played table tennis and bowled with the teams players and coaches.

In February 2016, the Make-A-Wish Foundation sponsored a trip for Howell, a huge NASCAR fan, to attend the Daytona 500.

Howell did his best to help others facing health scares. In April 2016, not long after Charles Westfall, a Duke fan from Morrisville, had been diagnosed with cardiomyopathy and was told he might need a heart transplant, he received an encouraging call from Howell. Westfalls former roommate had met Howell at the Duke football office and gave Howell Westfalls number.

He left a voicemail describing what had happened to him, how it took a year to re-learn to walk after his cancer had spread to his spine, Westfall said Sunday. I can still hear a semblance of that message in that mountain twang in my head.

Photojournalist Viviane Feldman of Hillsborough, who graduated from UNC-Chapel Hill last May, published a photo essay entitled HB3 and Me about Howells battle with cancer.

On Saturday, the day after Howell died, condolences from the athletics programs poured out on social media.

This Young Angel on Earth changed many lives for the better in 13+ years, Duke football coach David Cutcliffe posted on Twitter. Hes now an Angel of Heaven. RIP HOWELL BROWN lll.

Rest In Peace Howell Brown. Thank you for touching our lives & uplifting us with your spirit. N.C. Centrals athletics department tweeted.

Thankful to have known Howell Brown! former Duke football player and current assitant coach Cody Robinson wrote on Twitter . He did more in his short life than most do in a lifetime! Thanks for teaching us how to live HB3!

Jenna Frush, a Duke Medical School student who was a Duke basketball guard from 2011-15, was among a group of people who spent time with Howell daily over the final month of his life.

He was stronger than cancer can ever be, Frush said.

On Saturday, she posted a photo on Instagram of a smiling Howell Brown wearing a Duke T-shirt with these words:

Youre my hero, bud, Frush said. I love you with all my heart.

Originally posted here:
Howell Brown, cancer patient who inspired Duke Blue Devils and ... - News & Observer

Five vials of a live vaccine virus used to inoculate against smallpox were seized by the U.S. Marshals from stem cell treatment centers in California that had been used to treat cancer patients.

The potentially dangerous and unproven treatment combined a live version of the Vaccinia virus vaccine and stem cells that originated in body fat, and injected them directly into patients tumors, according to the U.S. Food and Drug Administration.

The treatments were apparently not approved by the regulatory agency.

The FDA will not allow deceitful actors to take advantage of vulnerable patients by purporting to have treatments or cures for serious diseases without any proof that they actually work, said Scott Gottlieb, the FDA Commissioner.

The Vaccinia virus vaccine was instrumental in eradicating smallpox in the 20th century though it does not contain smallpox itself. Currently doses are reserved for people at risk for smallpox, including members of the military who may have to face a bioterrorism event.

The U.S. Marshals seized five vials of the vaccine on Friday. Each of the containers held approximately 100 doses of the vaccine. Four were recovered intact but the fifth had been partly used.

StemImmune touts stem-cell-based immunotherapies capable of unleashing a stealth attack on cancer on its website. The company, which was founded in 2014, also contends it is working with the FDA on an investigational new drug application to allow a Phase I and Phase II clinical trial of its leading product candidate.

In a statement released to Laboratory Equipment, StemImmune said safety of patients is paramount.

StemImmune is fully cooperating with the FDA about the development and use of its stem cell-based investigational cancer therapy, the company said. Our primary concern has and continues to be the safety and well-being of patients in clinical trials and compassionate use programs. At this time, we are working to understand and address the questions raised by the FDA about the use of our therapy for cancer patients in individual compassionate use programs in clinics. As more information becomes available to us, we will update this statement.

The contested treatments were administered to cancer patients at two California Stem Cell Treatment Centers, one in Rancho Mirage and the other in Beverly Hills.

The patients could have had compromised immune systems and may have been at risk for adverse effects like heart inflammation, the FDA contends.

The people who were in contact with the patients may have been at risk additionally for becoming infected with the live virus used in the vaccine. The health effects could have included inflammation and swelling for at-risk unvaccinated people, including those who were pregnant, who had heart or immune system problems, or skin problems like eczema and psoriasis or other conditions, they FDA said.

I especially wont allow cases such as this one to go unchallenged, where we have good medical reasons to believe these purported treatments can actually harm patients and make their conditions worse, added Gottlieb.

Smallpox has been considered eradicated since the last case was reported in Kenya in 1977 although some advocate stockpiling the Vaccinia vaccines in case of a biological weapons terror attack.

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FDA, US Marshals Seize Smallpox Vaccine Used for Stem Cell Cancer Treatment - DeathRattleSports.com

A US study has shown high dose Vitamin C halts the progression of blood cancer in mice by encouraging "faulty" stem cells in the bone marrow to die.

The findings, published in journal Cell, has raised the possibility of new new combination therapies for leukaemia patients carrying a specific gene mutation known as TET2.

"We're excited by the prospect that high-dose vitamin C might become a safe treatment for blood diseases caused by TET2-deficient leukemia stem cells, most likely in combination with other targeted therapies," said Dr Benjamin Neel, director of the Perlmutter Cancer Center.

The TET2 gene carries a protein that produces and matures stem cells, a process beneficial to blood cancer patients.

It's estimated TET2 mutations are found in 10 per cent of patients with acute myeloid leukemia (AML), 30 per cent of those with a form of pre-leukemia called myelodysplastic syndrome, and in nearly 50 per cent of patients with chronic myelomonocytic leukemia.

Previous research had suggested that TET2 could be activated by high-doses of Vitamin C.

"So we had the idea that high-dose Vitamin C be used as a therapy for some forms of Myelodysplastic syndrome and acute myeloid leukemia, particularly those forms who have mutations in this gene called TET2," said Dr Neel.

In the lab, scientists at the Perlmutter Cancer Center in New York added high doses of the Vitamin C to human leukemia cells carrying the TET2 mutations.

"We saw that that stops the growth," said pathologist Dr Iannis Aifantis.

A similar result was produced when tested on genetically engineered mice, according to the study.

It was also found the Vitamin C treatment had an effect on leukemic stem cells that resembled damage to their DNA, says first study author Luisa Cimmino.

"For this reason, we decided to combine Vitamin C with a PARP inhibitor, a drug type known to cause cancer cell death by blocking the repair of DNA damage, and already approved for treating certain patients with ovarian cancer," she said.

The combination had an enhanced effect on leukemia stem cells, further shifting them from self-renewal back toward maturity and cell death.

Scientists are now trying to apply the findings in clinic, with plans underway for a human clinical trial later this year.

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Vitamin C stops blood cancer in mice - NEWS.com.au

Although the traditional chemotherapy drug, cisplatin, is somewhat successful in its own right, researchers have discovered that when combined with a new experimental drug the results are astounding. In a recent University of Michigan study carried out using mice, researchers found that when this combination was used in mice it destroyed a rare form of salivary gland tumor and stopped it from recurring within a 300 day period.

This rare form of cancer in question is called *adenoid cystic carcinoma, or ACC for short. It affects around 3,000 to 4,000 people annually and is most commonly found in the salivary glands. Unfortunately, its one of those cancers that isnt usually detected until its at an advanced stage, is very resistant to therapy, and as of yet has no cure. Normally these type of tumors is treated with surgery and radiation. Chemotherapy is usually avoided as ACC is very slow-growing and chemotherapy is better used on rapidly growing tumors, confirmed Jacques Nor, a UM professor of dentistry, otolaryngology, and biomedical engineering, and principal investigator on the study.

The experimental drug used in the study is called MI-773, and when combined with cisplatin, is very effective at warding off cancer. It does this by preventing the interaction taking place that disarms the vital cancer-fighting protein, p53. As the researchers explain it, by blocking that interaction, ACC cancer cells become sensitized to cisplatin. This drug MI-773 prevents that interaction, so p53 can induce cell death, says Nor. In this study, when researchers activated p53 in mice with salivary gland cancer, the cancer stem cells died.

As part of the study, researchers carried out two different types of experiments in order to fully test how much the ACC tumors were reducing in size as well as their recurrence patterns. The first experiment involved treating tumors in mice with the combination of MI-773 and cisplatin. The results were that the tumors shrank considerably from around the size of an acorn to almost nothing. In the second experiment, researchers removed the acorn sized tumors surgically and followed it up with one months worth of MI-773 treatment.

We did not observe any recurrence in the mice that were treated with this drug after 300 days (about half of mouse life expectancy), and we observed about 62 percent recurrence in the control group that had only the surgery, said Nor. Its our belief that by combining conventional chemotherapy with MI-773, a drug that kills more cancer stem cells, we can have a more effective surgery or ablation. One slight drawback to the study is that it is based on an observational period of 300 days, whereas nearly half of all ACC tumors recur only after around 10 years. Its still early days for the drug combo in terms of being used on human patients but is still a good place to start nonetheless.

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New Experimental Drug Kills Cancer Cells When Combined With Chemotherapy - TrendinTech

The study suggests it may encourage blood cancer stem cells to die.

Researchers say Vitamin C may "tell" faulty stem cells in the bone marrow to mature and die normally, instead of multiplying to cause blood cancers.

They explained that certain genetic changes are known to reduce the ability of an enzyme called TET2 to encourage stem cells to become mature blood cells, which eventually die, in many patients with certain kinds of leukaemia.

The new study, published online by the journal Cell. found that vitamin C activated TET2 function in mice engineered to be deficient in the enzyme.

Study corresponding author Professor Benjamin Neel, of the Perlmutter Cancer Centre in the United States, said: "We're excited by the prospect that high-dose vitamin C might become a safe treatment for blood diseases caused by TET2-deficient leukemia stem cells, most likely in combination with other targeted therapies."

He said changes in the genetic code that reduce TET2 function are found in 10 per cent of patients with acute myeloid leukaemia (AML), 30 per cent of those with a form of pre-leukaemia called myelodysplastic syndrome, and in nearly 50 per cent of patients with chronic myelomonocytic leukaemia.

Such cancers cause anaemia, infection risk, and bleeding as abnormal stem cells multiply in the bone marrow until they interfere with blood cell production, with the number of cases increasing as the population ages.

Prof Neel said the study results revolve around the relationship between TET2 and cytosine, one of the four nucleic acid "letters" that comprise the DNA code in genes.

To determine the effect of mutations that reduce TET2 function in abnormal stem cells, the researchers genetically engineered mice such that the scientists could switch the TET2 gene on or off.

Similar to the naturally occurring effects of TET2 mutations in mice or humans, using molecular biology techniques to turn off TET2 in mice caused abnormal stem cell behaviour.

Prof Neel said, remarkably, the changes were reversed when TET2 expression was restored by a genetic trick.

Previous work had shown that vitamin C could stimulate the activity of TET2 and its relatives TET1 and TET3.

Because only one of the two copies of the TET2 gene in each stem cell is usually affected in TET2-mutant blood diseases, the researchers hypothesised that high doses of vitamin C, which can only be given intravenously, might reverse the effects of TET2 deficiency by turning up the action of the remaining functional gene.

They found that vitamin C did the same thing as restoring TET2 function genetically.

By promoting DNA demethylation, high-dose vitamin C treatment induced stem cells to mature, and also suppressed the growth of leukaemia cancer stem cells from human patients implanted in mice.

Study first author Doctor Luisa Cimmino, of New York University Langone Health, said: "Interestingly, we also found that vitamin C treatment had an effect on leukaemic stem cells that resembled damage to their DNA.

"For this reason, we decided to combine vitamin C with a PARP inhibitor, a drug type known to cause cancer cell death by blocking the repair of DNA damage, and already approved for treating certain patients with ovarian cancer."

The researchers found that the combination had an enhanced effect on leukaemia stem cells, further shifting them from self-renewal back toward maturity and cell death.

Dr Cimmino said the results also suggest that vitamin C might drive leukaemic stem cells without TET2 mutations toward death, given that it turns up any TET2 activity normally in place.

Corresponding author Professor Iannis Aifantis, also of NYU Langone Health, added: "Our team is working to systematically identify genetic changes that contribute to risk for leukaemia in significant groups of patients.

"This study adds the targeting of abnormal TET2-driven DNA demethylation to our list of potential new treatment approaches."

Continued here:
Blood cancer: High doses of vitamin C could encourage stem cells to die - Express.co.uk

An experimental drug combined with the traditional chemotherapy drug cisplatin, when used in mice, destroyed a rare form of salivary gland tumor and prevented a recurrence within 300 days, a University of Michigan study found.

Called adenoid cystic carcinoma, or ACC, this rare cancer affects 3,000-4,000 people annually, and typically arises in the salivary glands. It's usually diagnosed at an advanced stage, is very resistant to therapy, and there's no cure. People may have read about ACC in the news lately, because elite professional runner Gabe Grunewald is currently undergoing her fourth round of treatment since her 2009 ACC diagnosis.

Typically, oncologists treat ACC tumors with surgery and radiation. They rarely use chemotherapy because ACC is extremely slow-growing, and chemotherapy works best on cancers where cells divide rapidly and tumors grow quickly, said Jacques Nr, a U-M professor of dentistry, otolaryngology and biomedical engineering, and principal investigator on the study.

The Nr lab treated ACC tumors with a novel drug called MI-773, and then combined MI-773 with traditional chemotherapy cisplatin. MI-773 prevents a molecular interaction that causes tumor cells to thrive by disarming the critical cancer fighting protein, p53.

Study co-author Shaomeng Wang, U-M professor of medicine, pharmacology and medicinal chemistry, discovered MI-773, which is currently licensed to Sanofi.

Researchers believe that blocking that interaction sensitized ACC cancer cells to cisplatina drug that under normal conditions, wouldn't work. When administered to the mice with ACC tumors, the cisplatin targeted and killed the bulk cells that form the tumor mass, while MI-773 killed the more resistant cancer stem cells that cause tumor recurrence and metastasis.

"This drug MI-773 prevents that interaction, so p53 can induce cell death," Nr said. "In this study, when researchers activated p53 in mice with salivary gland cancer, the cancer stem cells died."

The key is that in many other types of cancer, p53 is mutated so it can't kill cancer cells, and this mutation renders the MI-773 largely ineffective. However, in most ACC tumors p53 is normal, and Nr said researchers believe this makes these tumors good candidates for this combined therapy.

Researchers performed two different types of experiments to test ACC tumor reduction and recurrence. First, they treated tumors in mice with a combination of MI-773 and cisplatin, and tumors shrank from about the size of an acorn to nearly zero.

In the second experiment, the acorn-sized tumors were surgically removed, and for one month the mice were treated with MI-773 only, with the hope of eliminating the cancer stem cells that fuel recurrence and metastasis.

"We did not observe any recurrence in the mice that were treated with this drug after 300 days (about half of mouse life expectancy), and we observed about 62 percent recurrence in the control group that had only the surgery," Nr said. "It's our belief that by combining conventional chemotherapy with MI-773, a drug that kills more cancer stem cells, we can have a more effective surgery or ablation."

One limitation of the study is that it's known that about half of all ACC tumors recur only after about 10 years, and this observational period was only 300 days.

In a typical metastasis, the cancer cells spread through the blood to other parts of the body. But ACC cancer cells like to move by "crawling" along nerves, and it's common for ACC tumor cells to follow the prominent facial nerves to the brainpicture a mountain climber ascending a ropewhere it's often fatal.

Research is still too early-stage to know how humans will respond, and the drug will work primarily in tumors where p53 is normal. If p53 is mutated, which is fairly common in other tumor types, this drug won't work as well, Nr said.

The work was funded by the Adenoid Cystic Carcinoma Research Foundation, U-M and the National Institutes of Health.

The study, "Therapeutic Inhibition of the MDM2-p53 interaction prevents recurrence of adenoid cystic carcinomas," appeared earlier this year in the journal Clinical Cancer Research.

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Cisplatin Combination Kills Rare Cancer Cells in Mice - Bioscience Technology

Only 3,224 miles to go. Let me at it, says Geoff Thomas as he prepares to set off around Spain, 21 days of pure agony covering every inch of La Vuelta, each stage completed 24 hours before the peloton attacks the third and final grand tour of the season.

Thomas is a cancer survivor dedicated through his own foundation to raising cash and awareness of blood cancer, the disease that struck down the former Crystal Palace midfielder in 2003. Thomas was diagnosed with chronic myeloid leukaemia and given just three months to live. It was, he says, a dark place, yet here he is 12 years in remission and immersed in another lung busting slog to make life possible for others.

The scale of the challenge is insane, or stupid as Thomas describes it, for a bunch of amateur cyclists, one of whom is 67 years old. Having already completed the Giro dItalia and the Tour de France on the same terms this year there is no backing out now.

The initiative is after all called the Geoff Thomas Three Tours Challenge, and for better or worse he will be in the saddle on Friday alongside four equally committed travellers to attempt something only 39 professional riders have done before. The hope is to funnel more than 1m to Cure Leukaemia, the charity set up by the man he credits with saving his life Professor Charlie Craddock.

I got involved in all this through going through the illness. My only chance of survival was stem cell replacement. At my first meeting with a doctor I was given three months to live. The next day I saw Professor Craddock and he put me in intensive chemo straight away. He offered a different prognosis, saying I might have three years.

I was lucky my sister was a very good match as the donor. The treatment more or less kills you then they bring you back to life. My sister had to have the stem cells removed from her spine, quite a painful procedure. These days its like giving blood. They harvest the cells from a blood sample. As a result more people are going on the donors list.

Back when I was diagnosed there was a clinical trial that I couldnt get on. It proved very successful, resulting in survival rates of more than 90 per cent for the drug involved. There was no real infrastructure to run clinical trials back in 2003. A lot of hospitals did not have the facilities, no clinical researchers in place etc. For a small amount of money in the grand scheme we are now able to put that into place.

Hospitals are now working together to get the results required and survival rates have gone up. As a result of the work we have done with clinical trials we have seen almost 200m worth of drugs available for free to patients on the NHS. And that is something we are really proud of.

The fight goes on, and so do the fundraisers, and for this one, you can never be ready, says Thomas. Some of the climbs are ridiculous. I dont look at the course or whats head I just think of bringing enough weight to bear on the pedal to turn the wheel. And you have to be lucky.

I missed a few days of the Tour de France after I fell and injured my hip. It was only on day two, a flat bit, and it became infected about ten days later. I was gutted to have to stop but I realised my aim is to get awareness out there and pull in the money that I know is making a difference to peoples lives. This is the final leg. Im determined tol stay on the bike this time and make it to the end.

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From death's door to mountain top, beating cancer the Geoff Thomas way - iNews

The Food and Drug Administration has approved a new medicine for use against a rare, rapidly progressing blood cancer after other treatments have failed.

The agency approved Pfizer Inc.'s Besponsa for patients with a type of advanced acute lymphoblastic leukemia. By then, life expectancy is low.

"These patients have few treatments available and today's approval provides a new, targeted treatment option," Dr. Richard Pazdur, the FDA's director for cancer drugs, said in a statement.

This year an estimated 5,970 Americans will be diagnosed and 1,440 will die from the cancer, according to the National Cancer Institute.

The drug will cost $168,300 without insurance for the typical nine-week treatment course.

In testing that included 218 patients, 36 percent given Besponsa had their cancer vanish for eight months on average; 17 percent of those given chemotherapy had complete remission for a median five months.

Besponsa is believed to work by blocking the growth of cancerous cells by binding to their surface.

The powerful injected drug, known chemically as inotuzumab ozogamicin, comes with the FDA's most-stringent warning because it can cause severe liver disease, including blocking veins in the liver. It also carries an increased risk of death in patients who have received a certain type of stem cell transplant.

Besponsa also can cause a decrease in blood-cell and platelet production, infusion-related reactions and problems with the heart's electrical pulses. Women who are pregnant or breastfeeding should not take Besponsa because it may harm a developing fetus or a newborn baby, the FDA warned.

More-common side effects include fatigue, severe bleeding, fever, nausea and headaches.

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FDA OKs Pfizer drug for rare, fast-killing type of leukemia - ABC News

How does the skin develop follicles and eventually sprout hair? A USC-led study, published in the Proceedings of the National Academy of Sciences (PNAS), addresses this question using insights gleaned from organoids, 3D assemblies of cells possessing rudimentary skin structure and functionincluding the ability to grow hair.

In the study, first author Mingxing Lei, a postdoctoral scholar in the USC Stem Cell laboratory of Cheng-Ming Chuong, and an international team of scientists started with dissociated skin cells from a newborn mouse. Lei then took hundreds of timelapse movies to analyze the collective cell behavior. They observed that these cells formed organoids by transitioning through six distinct phases: 1) dissociated cells; 2) aggregated cells; 3) cysts; 4) coalesced cysts; 5) layered skin; and 6) skin with follicles, which robustly produce hair after being transplanted onto the back of a host mouse.

In contrast, dissociated skin cells from an adult mouse only reached phase 2aggregationbefore stalling in their development and failing to produce hair.

To understand the forces at play, the scientists analyzed the molecular events and physical processes that drove successful organoid formation with newborn mouse cells.

We used a combination of bioinformatics and molecular screenings, and the core facilities at the Health Sciences Campus have facilitated my analyses, said Lei.

At various time points, they observed increased activity in genes related to: the protein collagen; the blood sugar-regulating hormone insulin; the formation of cellular sheets; the adhesion, death or differentiation of cells; and many other processes. In addition to determining which genes were active and when, the scientists also determined where in the organoid this activity took place. Next, they blocked the activity of specific genes to confirm their roles in organoid development.

By carefully studying these developmental processes, the scientists obtained a molecular how to guide for driving individual skin cells to self-organize into organoids that can produce hair. They then applied this how to guide to the stalled organoids derived from adult mouse skin cells. By providing the right molecular and genetic cues in the proper sequence, they were able to stimulate these adult organoids to continue their development and eventually produce hair. In fact, the adult organoids produced 40 percent as much hair as the newborn organoidsa significant improvement.

Normally, many aging individuals do not grow hair well, because adult cells gradually lose their regenerative ability, said Chuong, senior author, USC Stem Cell principal investigator and professor of pathology at the Keck School of Medicine of USC. With our new findings, we are able to make adult mouse cells produce hair again. In the future, this work can inspire a strategy for stimulating hair growth in patients with conditions ranging from alopecia to baldness.

This article has been republished frommaterialsprovided byUSC Stem Cell. Note: material may have been edited for length and content. For further information, please contact the cited source.

Reference:

Lei, M., Schumacher, L. J., Lai, Y., Juan, W., Yeh, C., Wu, P., . . . Chuong, C. (2017). Self-organization process in newborn skin organoid formation inspires strategy to restore hair regeneration of adult cells. Proceedings of the National Academy of Sciences, 201700475. doi:10.1073/pnas.1700475114

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Molecular "How To" Guide For Producing Hair Follicles Obtained - Technology Networks