Electrospun gelatin-chondroitin sulfate scaffolds loaded with platelet lysate promote immature cardiomyocyte proliferation

The aim of the present work was the development of heart patches based on gelatin (G) and chondroitin sulfate (CS) to be used as implants to improve heart recovery after corrective surgery for critical congenital heart defects (CHD). Patches were prepared by means of electrospinning to obtain nanofibrous scaffolds and they were loaded with platelet lysate (PL) as a source of growth factors to further enhance the repair process. Scaffolds were characterized for morphology and mechanical properties and for the capability to support in vitro adhesion and proliferation of dermal fibroblasts in order to assess the system's general biocompatibility. Adhesion and proliferation of endothelial cells and cardiac cells (cardiomyocytes and cardiac fibroblasts from rat fetuses) onto PL-loaded patches was evaluated. Patches presented good elasticity and high stiffness suitable for in vivo adaptation to heart contraction. CS improved adhesion and proliferation of dermal fibroblasts, as proof of their biocompatibility. Moreover, they enhanced the adhesion and proliferation of endothelial cells, a crucial mediator of cardiac repair. Cell adhesion and proliferation could be related to elastic properties, which could favor cell motility. The presence of platelet lysate and CS was crucial for the adhesion and proliferation of cardiac cells and, in particular, of cardiomyocytes: G/CS scaffold embedded with PL appeared to selectively promote proliferation in cardiomyocytes but not cardiac fibroblasts. In conclusion, G/CS scaffold seems to be a promising system to assist myocardial-repair processes in young patient, preserving cardiomyocyte viability and preventing cardiac fibroblast proliferation, likely reducing subsequent uncontrolled collagen deposition by fibroblasts following repair.