Blindness Study Opens the Door for Further Stem Cell Trials
♫ Saturday, January 28th, 2012
Monday, news broke that researchers improved the vision of two
legally blind women by injecting embryonic
stem cells into their eyes[1].
Some media outlets are hailing the findings as showing a cure
for degenerative blindness, but, according to stem cell
experts, the most exciting implications of the study are that
neither woman experienced any ill effects from the transplant,
such as tumor growth or rejection.
"It provides promise that stem cells may indeed be safe," says
Paul Tesar, a genetics and neurosciences professor who focuses
on stem cell research at Case Western Reserve University School
of Medicine. "A lot of attention has been directed toward the
effectiveness of the trial, but without a clear control group,
we just have anecdotal evidence of effectiveness."
More importantly, the findings allow Advanced Cell Technology,
the group behind the trial, and other researchers to continue
human testing. ACT has already moved on to more trials,
according to Robert Lanza, chief scientific officer of the
company.
[Learn about
FDA approval for the stem cell study[2].]
ACT will begin ramping up the number of cells implanted into
patients' eyes to determine optimal dosages and to figure out
just how much vision can be restored. "We had another patient
treated yesterday," Lanza says.
The human eye is the perfect organ for early stem cell tests,
according to Tesar. Researchers have easy access to the eye to
monitor cell growth, so they're able to easily detect tumors if
they appear. It's also extremely easy to tell if the treatment
is working—a patient's vision is either improving or it isn't.
The four months both patients have been tumor free is "clearly
a sufficient amount of time" to test the safety of cells, at
least when compared to previous animal trials, Tesar says. In
failed animal trials, uncontrollable cell proliferation usually
happens within hours or days. Now that researchers know that
these types of stem cells appear to be safe for human
implantation, researchers can begin to "apply this type of
technology to any number of organs and conditions."
Lanza, of ACT, says the research could have far-reaching
implications for patients who suffer from all kinds of
degenerative vision conditions and other tough-to-treat
diseases. He says ACT is already working on stem cell
treatments that have cut the death rate in animals suffering
from a heart attack and that can restore blood flow to limbs
that might have otherwise been amputated.
[Most Americans
support embryonic stem cell research[3].]
He says ACT developed the treatment with the idea of slowing
degenerative eye conditions, but the effects in the company's
first two patients—one woman's eyesight improved from being
only able to detect motion to being able to read the top
several letters on a vision chart—surpassed his expectations.
"The goal of this therapy was not to cure blindness but to slow
down and prevent it. That we're actually seeing a vision
improvement is tremendous," he says. These early findings could
open the door to earlier and perhaps more effective treatment.
"We've got to be sure we're not going to harm the eye of a
young patient who still has relatively good vision. Ultimately
the real goal is to get rid of the diseases altogether."
Although it's too early to say how long the initial two
patients' vision improvements will last, Lanza is confident
that stem cells can be a long-term solution for a number of
diseases.
"There's a very real chance these cells could survive for a
very long time. It's a question we don't have the answer to,
but these cells survive the lifetime of the animals we've
studied," he says. "They may last years, decades. It's
something we need to follow."
Twitter: @jason_koebler[5]
References
-
^ injecting embryonic stem cells
into their eyes (health.usnews.com) -
^ Learn about FDA approval for
the stem cell study (health.usnews.com) -
^ Most Americans support embryonic
stem cell research (health.usnews.com) -
^ jkoebler@usnews.com
(www.usnews.com) -
^ @jason_koebler
(twitter.com)
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Blindness Study Opens the Door for Further Stem Cell Trials