In vivo tissue engineering of heart valves. Development of a new concept

Currently pursued tissue engineering principles of heart valves require tissue or stem cell-derived autologous cells with subsequent in vitro incubation on matrix scaffolds. Limitations of this approach are a long in vitro culture, a constantly accompanied risk of infection, and the requirement of a sophisticated, cost intensive infrastructure. An "off-the-shelf" heart valve with in vivo endothelialization and tissue regeneration potential represents an attractive alternative to overcome these limitations. Particularly for the pediatric patients, the development of heart valves with growth potential would significantly improve current treatment options. This article discusses different starter matrices, homing and immobilization strategies of host cells, and masking approaches of inflammation for in vivo surface and tissue engineering of heart valves. A novel concept based on highly specific DNA aptamers immobilized on the heart valve surface as capture molecules for endothelial progenitor cells (EPCs) circulating in the blood stream is presented.