For the first time, scientists have grown human heart valves from stem cells taken from amniotic fluid. This research suggests that someday, patients with heart defects may be able to grow their own replacement valves.

Through amniocentesis, scientists collected amniotic fluid and isolated fetal stem cells from it. They cultured the fluid in a lab dish, then placed it in a mold. Twelve heart valves grew in 4 to 6 weeks. Tests indicated that the valves functioned normally.

Researchers hope this biotechnology can be developed to cure infants with congenital heart defects, which can be detected by ultrasound during pregnancy. Ideally, new valves would be cultivated in the lab while the pregnancy progresses and be ready to implant at birth. However, implanting tissue-engineered heart valves in people is probably years away.

A report on this promising research was given at an American Heart Association conference in Chicago, Ill., last November.