The cardiovascular tissue-reactor: a novel device for the engineering of heart valves

The shortage of human donor valves and disadvantages of current mechanical and xenogenic valve grafts cause a growing demand for biologically engineered valves. We developed a bioreactor for in vitro transformation of porcine semilunar heart valves into human valves. The reactor design was optimized in order to achieve a complete removal of porcine cells by trypsinization and cellularization of the remaining matrix with human vascular cells. The physical parameters of the reactor were characterized. Based on these data, decellularization and cellularization protocols were developed and the successful application of protocols was investigated by immunohistochemistry. The resulting reactor consisted of two connectable and perfuseable modules. Heart valve structures of varying sizes could be mounted into the reactor and could be completely depopulated within 4 days by a sequence of enzymatic and mechanical treatments applied simultaneously to the valves. Complete cellularization with human cells could be achieved after optimizing the seeding design, density, and time.