Biomedical Engineering Reference
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significant improvement of the heart function. Ten of the patients in the study had
only cardiac bypass surgery and the other ten had bypass surgery and stem cells
injected into their damaged heart tissue during the surgery. Before surgery, the
patients who received the stem cells in addition to bypass surgery had an average
ejection fraction of 29.4%, while those who had bypass surgery alone had an aver-
age ejection fraction of 30.7%. In severe CHF ejection fraction (a standard measure
of heart function determined by the total amount of blood pumped out by the left
ventricle with each heart beat) is less than 35%. A person is considered to have a
good heart function when the ejection fraction is at least 55%. Six months after
surgery, the stem cell patients had an average ejection fraction of 46.1% compared
with 37.2% for those who had surgery alone. These results will encourage an
aggressive pursuit of cellular therapies as an option for CHF. It will change the
current approach, which is largely palliative, to one that is truly regenerative.
Further results from a prospective randomized trial by the University of
Pittsburgh in 2005 showed that patients with severe CHF who had not responded to
other treatments showed markedly improved heart function following a minimally
invasive procedure in which autologous bone marrow stem cells were injected
directly into the heart. This approach to cell therapy is feasible for the estimated
40% of CHF patients whose disease is unrelated to coronary blockages and who
therefore cannot benefit from bypass procedures. Further trials have been con-
ducted that involve giving stem cells to patients who are being implanted with heart
assist devices. When a donor heart becomes available for transplantation, the native
heart would be removed, allowing investigators the rare opportunity to look at the
heart in its entirety and to more closely examine the effects of the stem cells.
Further clinical trial will determine the safety and feasibility of injecting a patient's
own HSCs directly into the heart in patients with ischemic heart disease who are
scheduled for off-pump (beating heart) CABG surgery. In addition to assessing the
safety and feasibility of using a patient's own stem cells as a potential therapy for
heart disease, investigators are also trying to determine just how many stem cells
are needed to produce the best results.
AngioCell Gene Therapy for Congestive Heart Failure
AngioCell
™
(Angiogene) program is a pioneering recuperative approach that aims
to improve the function of damaged tissue, rather than merely treat the symptoms
of the disease. AngioCell is intended to restore the contractility of the heart tissue
with a cell therapy treatment that transplants muscle precursor cells loaded with a
gene to enhance blood vessel growth. The therapy also improves the blood flow and
oxygen uptake of the damaged heart by stimulating the growth of new blood vessels
in the myocardium, through a process of therapeutic angiogenesis.
Treating CHF with AngioCell begins with a small skeletal muscle biopsy taken
from the patient 2 weeks before surgery. Using a specialized technology process,
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