engineered from patients’ own tissue may offer a new treatment
for valvular heart disease, researchers reported at the American
Heart Association’s Scientific Sessions 2003.
tissue-engineered valve overcomes many of the problems with
mechanical or donor valves because it is a living structure from
the patient’s own tissue, and so it does not cause an
immunological reaction,” said Pascal M. Dohmen, M.D., head of
tissue engineering research and staff surgeon of the department
of cardiovascular surgery at Charité Hospital in Berlin,
colleagues presented data on the first 23 patients to receive
tissue-engineered pulmonary valves in the heart.
whose average age was 44, had aortic valve disease. The aortic
valve connects the heart’s left ventricle with the aorta, the
main artery that distributes blood throughout the body. A
diseased valve may either open or close improperly, and pressure
can build in the ventricle, injuring the heart.
Doctors can treat
the condition with drugs or by surgically replacing the
patient’s aortic valve with a donor valve, a mechanical valve or
the patient’s pulmonary valve. The pulmonary valve is between
the right ventricle and the pulmonary artery. In a surgical
“swap” called the Ross procedure, the abnormal aortic valve is
replaced with the pulmonary valve, and the pulmonary valve is
replaced with a donor valve.
colleagues engineered a new pulmonary valve from the patients’
own cells. They implanted the patients’ healthy pulmonary valve
into the aortic position. Then they implanted the
tissue-engineered valve in the right ventricular outflow tract,
where the pulmonary valve originally was.
With up to three
years of follow-up, the engineered valve’s performance was
“excellent,” Dohmen reported. Echocardiography showed that the
valves were functioning normally; the valve leaflets or flaps
appeared smooth and pliable and showed no signs of
The patients were
discharged from the hospital earlier, and were in better
condition than other patients. They had no post-operative
fever, which is often found in patients receiving donor heart
valves, Dohmen said. Furthermore, the recovery time was
To engineer the
new valve leaflets, the investigators extracted a small portion
of vein from the patient's leg or arm. Then they grew
endothelial cells from the vein on a donor valve scaffold in the
laboratory. The scaffold had been stripped of cells, leaving
only an elastin and collagen matrix for binding the patient's
studies, we have seen that this matrix or scaffold will be
absorbed by the body,” Dohmen said. “In the meantime, the
patient’s cells will form a new scaffold. After about a year,
the matrix is of the patients’ own material.
until now was to reconstruct the right ventricular outflow
tract,” he said. “You cannot do this with regular animal (pig)
or human donor valves because they will calcify early or
degenerate soon after implantation, especially in patients under
the age of 60.”
Dohmen limits the
use of the tissue-engineered valves to adults up to 60 years of
age, but plans to explore the growth potential of the valves,
with the hope of using them in children with congenital heart
The heart valve
scaffold technique is still considered experimental, he said.
Simon Dushe, Alexander Lembcke, Dietmar Kivelitz, Holger Hotz
and Wolfgang F. Konertz.