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 Dr. Carl J. Pepine, 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,” said R. 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 Dr. Douglas Losordo, 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.
Dr. Douglas E. Vaughan, 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.”
|
Source:- University of Florida Published on the
11th October 2007
|
Advertisement
 |
