November 17, 2002
IL (AHA) Ė In one of the first studies
of its kind, researchers discovered that bone marrow cells
injected directly into the heart significantly enhanced
function, according to findings reported at the American Heart
Associationís Scientific Sessions 2002.
contraction improved significantly after patients had their own
bone marrow injected into scar tissue caused by heart attacks.
Heart wall motion improved within weeks of treatment and
persisted for at least 10 months after treatment in 14 patients.
"The benefit (of
transplanting bone marrow into scar tissue of the heart) could
be seen only six weeks after injection," says Manuel Galinanes,
M.D., a heart surgeon at the University of Leicester in the
The technique is
a new way to strengthen heart muscle after a heart attack, he
Bone marrow has
been used for years to treat certain types of cancer and
disorders affecting the body's disease-fighting immune system.
Marrow transplantation is an attractive therapy because it can
form healthy new cells. Bone marrow also has the potential to
develop into many different types of cells.
"Bone marrow not
only can differentiate into heart cells, but also smooth muscle
cells, connective tissue cells and other types of cells to
reconstitute the entire structure of a tissue," Galinanes says.
have yet to prove that bone marrow creates a new cellular
infrastructure in heart scar tissue, but "that is the only
possible explanation," Galinanes says.
The British team
treated patients whose hearts had been severely damaged by heart
attacks. All patients had low ejection fractions, meaning the
heart muscle had lost much of its ability to pump blood into the
circulation. The bone marrow injections were given during
non-emergency coronary artery bypass surgery.
each patient had a stress test to confirm abnormal movement in
the walls of the heart muscle. The test involved injecting
dobutamine, a drug that simulates the effects of exercise on the
heart, including a faster heart rate, higher blood pressure and
more forceful contractions. Heart function, including wall
motion, was evaluated by echocardiography, an imaging test that
uses sound waves to generate pictures of the beating heart.
Bone marrow for
the treatments was obtained from the patientís sternum (breast
bone). The marrow was diluted in a small amount of the patientís
own blood, then injected directly into scar tissue identified
during the heart surgery.
"We confirmed the
scarring on the heart muscle before and during surgery,"
Galinanes says. "The ability to confirm the presence of scar
tissue with dobutamine stress echo before surgery, and then
confirm it again during surgery, told us that the affected area
was dysfunctional and the abnormality was irreversible. We
wanted to make sure that we were injecting the marrow into dead
tissue to help ensure that the injection would not pose any
serious risk to the patient."
echocardiography was repeated six weeks after surgery and again
at 10 months. The researchers looked at the effect of the bone
marrow on heart wall motion in the immediate vicinity of the
scar (regional) and in the left ventricle (global), the heartís
primary pumping chamber. The regional wall motion score
decreased significantly from an average of 2.41 prior to
injection to 2.16 after six weeks and 2.09 after 10 months. A
lower score means less movement abnormality. The global wall
motion score also decreased significantly from 1.96 before
surgery to 1.64 at six weeks. It remained largely unchanged at
1.65 after 10 months.
plan to study the effects of bone marrow injection in more
patients who have scar tissue and impaired heart function after
heart attacks. They've begun laboratory experiments to find out
how the bone marrow cells change the scar tissue and improve
The initial study
was limited to patients undergoing bypass surgery, but bone
marrow cells could be delivered to the heart through a much
smaller incision or possibly by non-surgical injection. If more
studies continue to show that the procedure is safe and improves
heart function, the researchers might begin to consider other
ways to implant the cells, Galinanes says.
If bone marrow
injection successfully restores heart function after heart
attacks, the treatment would be a welcome addition to other
competing strategies, such as gene therapy, growth factor
therapy and laser treatments, he says.
Mahmoud Loubani; Joan Davies, Ph.D.; Derek Chin, M.B.; John Pasi,
Ph.D.; and Peter Bell, M.D.