Human heart valve grown from stem cells offers hope for prenatal infants with defects

Researchers have successfully used umbilical cord stem cells to build a functional heart valve that may someday be perfected so that infants born with valve abnormalities could receive a new valve derived from their own stem cells, reports Philipp Schaefermeier, MD, University Hospital of Munich, Germany.

Researchers say that when early fetal echocardiography reveals a valve defect, it may be desirable to establish an autologous cell bank for the pediatric patient so that a heart valve can be grown for future use when conditions are ideal for surgery.

Dr. Schaefermeier explains that umbilical cord stem cells are harvested at the time of birth and cultured for 3 to 4 weeks until there are a sufficient number of cells. They are then cryopreserved for up to 12 weeks, reconstituted and applied to a biodegradable heart valve scaffold. Myofibroblast-type cells are applied to the valve scaffold first and are incubated for 1 week. Then epithelial-like cells are applied as a coating and are incubated for an additional week.

Analysis of the tissue shown reveals that compared with human pulmonary heart valves the engineered valves have 77.9 percent collagen, 85 percent as much glycosaminoglycan, and 67 percent as much elastin. In addition, functional testing of the tissue showed a spontaneous oscillation not before seen. “The tissue more resembles valvular tissue than vascular epithelial tissue,” explains Dr. Schaefermeier.

While this research may lead to the ability to grow heart valves for infants who will require them once born, so far, the ability to grow similar tissue using stem cells from the circulating blood of children has been more challenging. During human maturation, researchers suspect, something occurs in stem cells in serum that inhibits their ability to grow rapidly enough to produce enough cells to form an engineered valve.