UF researchers test stem cell therapy for heart patients
Published: Sunday, 7-Oct-2007
University of Florida doctors on Wednesday (Oct. 3) treated their
first patient enrolled in a new study designed to test whether
injecting stem cells into the heart helps restore blood flow to the
organ by prompting new blood vessels to grow.
UF researchers plan to test the experimental therapy in people with
severe coronary artery disease and daily chest pain who have not
responded to traditional medications or surgical procedures designed
to restore blood flow, such as angioplasty or bypass surgery.
"The general idea is that by providing these cells of blood vessel
origin, we hope to either generate new blood vessels from the growth
of these implanted cells or stimulate the heart to regenerate new
blood vessels from the cells that reside in it," said study
investigator Carl J. Pepine, M.D., chief of cardiovascular medicine
at UF's College of Medicine. "It's not completely clear whether it's
the actual cell itself that would do this or whether it's just the
milieu and the chemical signals that occur from the cells that would
result in this."
Each year, nearly half a million Americans with heart disease
experience severe chest pain because coronary arteries and the
smaller vessels that supply oxygen-rich blood to the heart muscle
become narrowed or blocked by plaque deposits or clots. These
blockages can trigger mini-heart attacks that, while too small to be
noticed as they occur, over time irreversibly damage the heart -
leading to disability, progressive heart failure or even death.
In the prospective, double-blind, placebo-controlled study, known as
the Autologous Cellular Therapy CD34-Chronic Myocardial Ischemia
Trial, or ACT34-CMI, UF researchers will study 15 Shands at UF
medical center patients to determine whether a person's own stem
cells can be used to effectively and safely treat chronic reductions
in blood flow to the heart, improving symptoms and long-term
outcomes. They also will evaluate whether participants report
improved quality of life and exercise tolerance, and whether the
heart functions better.
Participants will undergo screening tests and then receive a series
of injections of a protein that releases stem cells from the bone
marrow into the bloodstream. The cells, known as CD34+ stem cells,
help spur blood vessel growth and are harvested from the patient
during a procedure called apheresis, said Chris Cogle, an assistant
professor of medicine at the UF's College of Medicine Program in Stem
Cell Biology and Regenerative Medicine.
Participants will then be randomly assigned to receive one of two
dosing levels of the cells, or a placebo.
"Physicians will use a catheter-based electrical mapping system to
find muscle they think is still viable but not functioning,
David Anderson, an associate professor of medicine at UF and director
of interventional cardiology. "The cells are injected into viable
sites in the heart, which have poor blood flow, in the cardiac
catheterization laboratory at Shands at UF medical center."
Patients will be periodically evaluated by echocardiography and
magnetic resonance imaging over the course of a year after the
procedure. Although to date study subjects have tolerated this
procedure well, potential risks include infection, allergic
reactions, bleeding, blood clots and damage to the heart or its
vessels.
UF is one of 20 research sites participating in the national study,
which is evaluating a total of 150 patients and is sponsored by the
Cellular Therapies business unit of Baxter Healthcare Corp. and led
by principal investigator Douglas Losordo, M.D., of Northwestern
University's Feinberg School of Medicine. Baxter makes the cell-
sorting equipment used to isolate the cells from the blood.
Pending Food and Drug Administration approval, UF researchers,
through the National Heart, Lung and Blood Institute-funded
Cardiovascular Cell Therapy Research Network, are gearing up to
launch three other multicenter studies within the next several months
that use other types of a patient's own stem cells.
One trial focuses on patients who have had a heart attack within a
week preceding study enrollment, another focuses on patients whose
heart attack occurred within the preceding two to three weeks, and
the third focuses on patients with congestive heart failure or
chronic chest pain that has not responded to traditional treatment.
These studies will use stem cells taken directly from the patients'
bone marrow instead of stem cells isolated from the bloodstream,
Pepine said, and will test whether various cell therapies can improve
the heart's plumbing by helping to repair blood vessels or form new
ones and strengthen the heart muscle to improve its ability to pump
efficiently.
Douglas E. Vaughan, M.D., chief of the division of cardiovascular
medicine at Vanderbilt University Medical Center, said the study is
important and targets a challenging group of patients who need new
options.
"There's a lot of enthusiasm in the cardiovascular community about
the potential of cell-based therapies for the treatment of
cardiovascular diseases," Vaughan said, "and there is increasing
experience around the world in using bone marrow-derived stem cells
in patients with cardiovascular disease. There is growing confidence
this is going to be a safe form of therapy, but there are continuing
questions about how effective it will be and what its impact will be
in individual patients."
http://www.news-
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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