Bioactive porcine matrices in heart valve tissue engineering

Background: Platelet-gel (PG) as a storage vehicle of growth factors, can be considered for the application of growth factors in combination with mesenchymal stem cells (MSCs) to accelerate tissue regeneration and repair. Moreover, the addition of bioactive factors to porcine aortic valves could result in a more rapid repopulation and matrix synthesis in vitro and, in turn, optimize scaffold incorporation in vivo. The aim of this study was to evaluate the influence of different PG concentrations on in vitro ovine mesenchymal stem cell (oMSC) proliferation, migration and invasion. Moreover, the effect of PG on the repopulation of porcine aortic matrices was investigated. Methods: oMSCs were isolated from bone marrow, expanded and differentiated to adipose tissue, cartilage and bone. oMSCs were exposed to different concentrations of supernatant (0-2x106 plt/mL). After a culture period of 72 hours, cellular proliferation was evaluated by an MTS assay. oMSC motility and invasiveness were assayed using a Boyden chamber. Decellularized porcine aortic valve matrices were incubated with the PG. Release of growth factors from the matrices was evaluated by ELISA. MSC repopulation in vitro was evaluated after 3 to 7 days by light microscopy. Results: oMSCs were shown to display the trilineage differentiation potential. The supernatant was able to stimulate cell proliferation already at a minimum concentration of 8x104plt/mL. Increasing platelet concentrations (