Tissue engineering of cardiac valve prostheses I: development and histological characterization of an acellular porcine scaffold.

Several deficiencies in current heart valve prostheses make them problematic for use in younger patients. Tissue valve substitutes are non-viable with a life expectancy of only 10-15 years, while mechanical valves require long-term anti-coagulation therapy. A solution to these problems would be to develop a tissue-engineered heart valve containing autologous cells, enabling the valve to maintain its biochemical and mechanical properties, yet grow with the patient. The study aim was to optimize a protocol to produce a porcine acellular matrix scaffold for use in developing a tissue-engineered heart valve. Fresh porcine aortic valve leaflets were treated with Triton X-100, sodium dodecyl sulfate (SDS), sodium deoxycholate, MEGA 10, TnBP, CHAPS, and Tween 20, over a range of concentrations, in the presence of protease inhibitors for up to 72 h. Histological analysis was used to detect the major structural proteins of the heart valve, collagen I, elastin and glycosaminoglycans. After 72 h, most protocols resulted in the retention of large numbers of whole cells and cell fragments. Only SDS (0.03-1%) or sodium deoxycholate (0.5-2%) resulted in total decellularization at 24 h. Histological analysis of acellular matrices showed that the major structural proteins had been retained and appeared to be intact. Protocols utilizing SDS or sodium deoxycholate were successful for leaflet decellularization, and histological analysis showed that the major structural components of the valve matrix had been maintained. These methods are being developed further with a view to reseeding with autologous cells to produce tissue-engineered solutions for clinical implantation.