Preparation of calcium silicate/decellularized porcine myocardial matrix crosslinked by procyanidins for cardiac tissue engineering

Decellularized myocardial extracellular matrix (ECM) patches have promising potential for myocardial repair, due to the well-preserved compositional cues, good biocompatibility and non-immunogenicity. However, the lack of vascularization and their low mechanical properties, chemical instability caused by decellularization process limit their application in cardiac tissue engineering. Therefore, we used calcium silicate (CS) extracts interpenetration method to prepare CS-loaded bioactive scaffold, since CS bioceramic was reported to have stimulative effect on angiogenesis. Meanwhile, procyanidins (PC), a natural plant polyphenol, was utilized to crosslink the decellularized myocardial ECMs, aiming at enhancing the mechanical properties and resistance to enzymatic proteolysis. The results showed that PC-crosslinked pcECMs displayed great crosslinking stability and efficiency, improved tensile strength and chemical stability as compared with non-crosslinked group, and the enhancement was depended on the concentration of PC. The CS-loaded ECMs showed stable Ca and Si ions release during 7 days and the ion concentration was adjusted in the range with angiogenic potential by controlling the original concentration of CS extracts. Cytotoxicity assay showed that the CS-loaded pcECMs crosslinked by PC were cytocompatible for supporting the adhesion and proliferation of H9c2 cardiomyoblasts, endothelial cells and fibroblasts. Moreover, the CS incorporating could enhance the proliferation rate and angiogenic gene expression of endothelial cells effectively. These findings verified the feasibility of PC crosslinking and CS incorporation as a novel approach to prepare bioactive complex decellularized myocardial scaffold, which can be applied to cardiac tissue engineering for myocardial repair.