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Tissue Engineering
Amniotic Cells May Be Source of New Tissue
Pediatric surgeons trying to fix birth defects often face a supply problem, unable to borrow enough tissue from their tiny patients to repair abnormalities elsewhere on the body. Often the surgeon uses a synthetic patch made of teflon, but it can tear out of the tissue and does not make as ideal a material as host tissue. The laboratory of Dario Fauza, HMS instructor in surgery at Children's Hospital and the Harvard Center for Minimally Invasive Surgery, sponsored by U.S. Surgical Corp., has been pursuing the goal of engineering a ready supply of fetal tissue that can be used to correct congenital abnormalities at birth.
A scanning electron micrograph shows a synthetic scaffold at left that provides a degradable framework for engineered tissue. At right, the same scaffold has been seeded with human mesenchymal amniocytes that have formed tissuelike layers. Photos courtesy of Amir Kaviani
In the past few years, Fauza, postdoctoral fellow Amir Kaviani, and their colleagues have worked to solve this problem by collecting a small amount of the fetus's tissue in utero and using the cells to engineer replacement tissue. In their latest study, the team has potentially sidestepped the need even for harvesting fetal tissue. Instead, they have found a source of usable fetal cells in an unlikely and much more accessible placeÑthe amniotic fluid.
Dario Fauza (left) and Amir Kaviani have found fetal cells in amniotic fluid that may help engineer needed tissue for surgery. Photo by Jeff Cleary
The team first isolated fetal mesenchymal cells, which form the connective tissues of the body, from the amniotic fluid of sheep. They proliferated the cells in culture and seeded them onto a synthetic polymer scaffold that guides them to form tissuelike layers. The researchers repeated the experiment using human amniocytes, and Kaviani presented the results at a meeting of the British Association of Pediatric Surgery on July 20.
"We used to think the amniotic fluid was sort of a garbage bag," Fauza said. But not only did the amniotic cells form dense layers equal to tissue engineered from fetal samples, they actually grew faster in culture than comparable fetal cells. It is possible that many of the cells were shed from the fetus earlier in development and retain the ability of younger cells to grow more rapidly.
—Courtney Humphries
Copyright 2001 by the President and Fellows of Harvard College
