StemCell Therapy

Scientists grow a rat lung in the laboratory

By LAURAN NEERGAARD (AP) – 4 days ago

WASHINGTON — It's an early step toward one day building new lungs: Yale University researchers took apart and regrew a rat's lung, and then transplanted it and watched it breathe.

The lung stayed in place only for an hour or two, as the scientists measured it exchanging oxygen and carbon dioxide much like a regular lung — but also spotted some problems that will take more research to fix.

Still, the work is a step in the science fiction-sounding hunt for ways to regenerate damaged lungs — although lead researcher Dr. Laura Niklason cautions that it may be 20 or 25 years before a build-a-new-organ approach is ready for people.

The work was reported online Thursday in the journal Science.

Nearly 400,000 people die of lung diseases each year in the U.S. alone, according to the American Lung Association, and lung transplants are far too rare to offer much help.

But how to replicate these spongy organs? Niklason's team stripped an adult rat's lung down to its basic structural support system — its scaffolding — to see if it's possible to rebuild rather than starting completely from scratch.

First, they essentially washed away the different kinds of cells lining that lung. It gradually faded from a healthy red to a white structure of mostly collagen and other connective tissue that maintained the shape and stretchiness of the original lung, even the tubes where airways would be.

This scaffolding is like a universal donor that shouldn't pose rejection problems, said Niklason: "Your collagen and my collagen are identical."

The researchers put the lung scaffolding into a bioreactor, an incubator-style container designed to mimic the environment in which fetal lungs develop, with fluid pumping through them.

Then they injected a mixture of different lung cells taken from a newborn rat. In the bioreactor, those cells somehow migrated to the right spots and grew air sacs, airways and blood vessels.

In short-term implants in four different rats, engineered lungs replaced one of the animals' native lungs and proved 95 percent as efficient at exchanging oxygen and carbon dioxide, Niklason said.

However, among the problems she spotted were small clots that formed inside the engineered lung, a sign that the new cells hadn't grown a thick enough cover in some places.

The biggest challenge: For this approach ever to work without a person's body rejecting the new tissue, scientists would need to use a recipient's own cells, Niklason explained. But there isn't a way yet to cull the kind of personalized stem cells that would be needed, meaning stem cell research must improve first, she said.

This overall approach also worked in a 2008 University of Minnesota experiment that grew a beating rat heart, and Minnesota researcher Dr. Doris Taylor welcomed the Yale lung work.

Separately in Science, a Harvard University team coated a flexible chip with layers of living lung cells, creating a laboratory tool that mimics some of the action of a breathing human lung. The goal: To replace some of the animal studies needed to test how lungs react to environmental toxins or inhaled drugs.

Online: http://www.sciencemag.org

At three years old, Justin, a German Shepherd-cross, seems too young to be afflicted with osteoarthritis.

But his early life, marred by abuse, left Justin with arthritis, hip dysplasia, flesh-eating disease and a cracked molar. “He is a big mess. A lot of people would euthanize him, but I don’t want to give up on him,” said Jamie Lee, a Vancouverite who adopted Justin nine months ago from an animal rescue group.

The mission to relieve Justin’s pain brought Ms. Lee to the frontier of veterinary medicine: stem-cell therapy.

It’s one of the holistic practices, including raw food, acupuncture and massage, showcased at The Petnership Project Tradeshow and Lecture Series in Vancouver on Saturday.

Justin broke one of his legs as a puppy, but his owners never took him to the vet. The injury resulted in osteoarthritis that spread to his other limbs.

The specialist said they could try an implant to relieve the pain, but there was a high risk that failure could lead to amputation, Ms. Lee said.

Instead, Ms. Lee decided to try an innovative treatment called stem-cell therapy, a procedure that extracts cells from the animal’s fat and moves them into the injured area to jump-start healing.

The procedure took less than 48 hours, even though the fat was shipped to a San Diego-based company called Vet-Stem. The company extracts cells from the fat tissue and sends back a needle to be inserted into the pet’s source of pain.

Ms. Lee said Justin’s mobility has gradually increased by 50 per cent after the surgery. Now the pooch, who could barely walk, can stroll for an easy 30 minutes.

But pain relief doesn’t come cheap: Ms. Lee spent around $4,000 to get treatment for all four of Justin’s joints.

The average treatment cost runs between $1,200 and $1,500, said Loridawn Fawcett of Vancouver’s The Healing Place, who advised Justin’s treatment. The treatment only has to be done once, unless there is a new injury, she said.

Results can take up to three months, said Dr. Fawcett, adding the success rate is 80 per cent.

Most dogs have the therapy to treat arthritis, but it can help heal fractures, tendon-ligament injuries and liver disease, said Dr. Fawcett.

This therapy goes beyond stem-cell treatments available for humans in Canada, which require adult stem cells to be taken from a donor’s bone marrow. Research into whether humans can successfully harvest and use their own stem cells for regenerative therapy is ongoing, but is not yet approved.

While it may be exciting, Thomas Koch of the Ontario Veterinary College cautions the science behind the therapy is not proven. The cells may have a therapeutic effect, he said, but scientists don’t know exactly how or why.

“The marketing is trumping the science and it’s obviously feeding off the hope and hype in the whole area of regenerative medicine,” said Dr. Koch. Still, the procedure seems safe in terms of infection because patients are receiving their own cells, he said, adding that there is still a risk people are paying for ineffective therapy.

It was worth it for Justin, said Ms. Lee.

She advises other pet owners considering the option to do some research, get a full blood test and consult with their vet about whether stem cell therapy is the right choice for their pet.

“If something goes wrong in surgery, you cannot go back,” said Ms. Lee. “With stem-cell therapy, what’s the worst that can happen? You pay more money.”