The role of biomaterials in the direction of cardiac stem cells properties, differentiation and extracellular matrix interactions in cardiac tissue engineering

Introduction: One of the main problems in the rapid translation of preclinical cell‐based therapy to restore damaged myocardium is to find the best delivery route and the best time of cell injection into the myocardium. Intramyocardial injection of stem cells is by far the mostused delivery technique in preclinical studies. Three‐dimensional scaffolds may be used to deliver a limited number of stem cells in their undifferentiated state, but many biomaterials may cause a foreign body reaction on their own. We have recently demonstrated that c‐Kit positive cardiac progenitor cells are able to organize themselves into a tissue‐like cell mass in collagen I three‐dimensional cultures within 72h in 5% horse serum and that inside an Open Pore Poly‐lactic acid scaffold, commercially available, these cells can create an organized elementary myocardium. Hypothesis: We assessed the hypothesis that poly‐lactic and fibroin scaffolds, designed to deliver cardiac progenitor cells in the infarcted region of the heart, may induce a better differentiation into cardiomyocytes. Methods: For the synthesis of PDLLA scaffolds, the Poly (D,L lactic acid) (RESOMER® 207, MW = 252 kDa) polimer were used (6.7%) in Dicloromethane/Dimetilformamide (DCM/DMF) 70/30 (v/v). The three‐dimensional structure was obtained by salt‐leaching, using NaCl crystals as porosity agent (NaCl < 224 μm and