Objective: Degradation mechanisms of cardiovascular bioprostheses may play an important role in bioartificial implants. The fate of acellular implanted and cellular cardiovascular scaffolds was examined in an in vivo model.
Methods: Decellularized or native ovine carotid artery (CA, n=42) and aorta (AO, n=42) were implanted subcutaneously into rats for 2, 4 and 8 weeks. Immunohistochemical methods were used to monitor repopulation. Desmin-vimentin, CD31-, CD4- and CD18-antibodies for myocytes, endothelium, and inflammatory cell-infiltration, respectively. Calcification was detected by von-Kossa staining. Cell density was quantified by DNA-isolation.
Results: Acellular AO and CA matrices showed progressive calcification. Cellular AO and CA matrices trigger a strong inflammatory reaction which subsides after two weeks. CA scaffolds are revascularized progressively, whereas AO biocomposites degenerate. Calcification is less pronounced in cellular AO scaffolds and lacking in CA.
Conclusion: Acellular bioartificial implants demonstrate degradation mechanisms similar to currently applied cardiovascular bioprostheses. Cellularized viable implants are promising clinical alternatives.