Scientists Grow Heart Valves Employing Amniotic Stem Cells
ASSOCIATED PRESS
November 16, 2006; Page D4
CHICAGO -- Scientists for the first time have grown human heart valves using stem cells from the fluid that cushions babies in the womb -- offering a revolutionary approach that may be used to repair defective hearts in the future.
The idea is to create new valves in the lab while the pregnancy progresses and have them ready to implant in a baby with heart defects after it is born.
The Swiss experiment follows recent success growing bladders and blood vessels and suggests people may one day be able to grow their own replacement heart parts -- in some cases, before they're born.
It's one of several sci-fi tissue engineering advances that could lead to homegrown heart valves for infants and adults that are more durable and effective than artificial or cadaver valves.
"This may open a whole new therapy concept to the treatment of congenital heart defects," said Dr. Simon Hoerstrup, a University of Zurich scientist who led the work, which was presented yesterday at an American Heart Association conference.
Also at the meeting, Japanese researchers said they had grown new heart valves in rabbits using cells from the animals' own tissue. It is the first time replacement heart valves have been created in this manner, said lead author Dr. Kyoko Hayashida.
One percent of all newborns, or more than one million babies born world-wide each year, have heart problems. These kill more babies in the U.S. in the first year of life than any other birth defect, according to the National Institutes of Health.
Heart-valve defects can be detected with ultrasound tests at about 20 weeks of pregnancy. At least one-third of afflicted infants have problems that could be treated with replacement valves, Dr. Hoerstrup said.
Conventional procedures to fix faulty heart valves all have drawbacks. Artificial valves are prone to blood clots and patients must take anticlotting drugs for life. Valves from human cadavers or animals can deteriorate, requiring repeated open-heart surgeries to replace them, Dr. Hijazi said. That's especially true in children, because these valves don't grow along with the body. Valves made from the patient's own cells are living tissue and might be able to grow with the patient, said Dr. Hayashida, a scientist at the National Cardiovascular Center Research Institute in Osaka.
The Swiss procedure has another advantage: using cells the fetus sheds in amniotic fluid avoids controversy because it doesn't involve destroying embryos to get stem cells.
online.wsj.com |
