TUESDAY, Sept. 11, 2007 (HealthDay News) -- Researchers are reporting an advance in tissue engineering techniques that has helped them move a step closer toward a living replacement heart valve for children.
Such a valve would help children with certain birth defects avoid repeated valve replacement surgeries.
Research into living heart valves "holds the promise of fulfilling the criteria we need for the perfect valve substitute," said Dr. Peter Manning, director of cardiothoracic surgery at Cincinnati Children's Hospital Medical Center, who's familiar with the study. "A lot of us have optimism that it will have an impact, hopefully in the near future."
Currently, artificial heart valves are the only option for children with certain kinds of heart defects that disrupt the functioning of the pulmonary heart valve. But surgery can cause infections, and the valves need to be replaced as children grow, because the valves don't automatically become larger.
There's "no perfect valve substitute that we have for anyone," Manning said. "It doesn't exist."
But over the past 10 to 15 years, he said, researchers have been looking into an alternative -- valves engineered from living tissue that would be able to grow as the child grows. "It's something that has been on the horizon but not quite there for clinical use," he said.
In the new study, published Sept. 11 in the journal Circulation, researchers at Children's Hospital Boston and elsewhere reported that they were able to use tissue engineering techniques to add animal cells to a kind of cellular scaffold and create tissue like that in pulmonary heart valves. The cells used are precursors of cells that line blood vessel walls.
The researchers hope to further perfect the technique and test replacement heart valves in animals.
Research will continue in animals for some time before reaching humans, said study senior investigator Dr. John Mayer of Children's Hospital Boston's Department of Cardiac Surgery. "There are 1,000 little details that go into making a heart valve, because there are so many components with so
many variables -- the scaffolding, the cells types, the condition under
which the structures are grown, etcetera," he said. "All of these variables have to be explored to find the optimal circumstances for each component."
How long will that take? "While this research is very encouraging, we still have a lot of questions to answer," Mayer said. "It'll be at least five years, maybe longer, before this is in clinical trial" with humans.
According to Manning, researchers have been trying to bioengineer heart tissue for more than a decade. "This article represents one little facet of what they're doing," he said. "There's a lot of research that's been out there."
While the study isn't groundbreaking, it does describe "one new wrinkle," Manning said.
As for the future, "when I'm meeting with families and telling them now about valves being replaced in children, I tell them that I expect that within the lifestyle of this child, they'll end up with a bioengineered valve," Manning said. "It's very likely that within the next decade, we'll start seeing applications in humans, maybe even sooner."
More information
For more on heart valve replacement, visit the U.S. National Institutes of Health.
