CARDIAC STEM CELLS AND BIOMATERIALS: INDUCTION OF MYOGENIC DIFFERENTIATION AND IMPLANTION OF BIOSYNTHETIC AND NATURAL MATRICES IN THE ADULT HEART

Principal purpose of regenerative medicine for the cardiac tissue is to find the best way to inoculate stem cells in a specific myocardial area damage, improving their homing, integration and survival. To achieve this goal, the field of biomaterials is important to bypass this obstacles, modulating the environment for implanted cells and enhance CSC function in the heart. Biomaterials can mimic or include naturally occurring extracellular matrix and instruct stem cell function in different ways: promoting angiogenesis, enhancing stem cell engraftment and differentiation, and accelerating electromechanical integration of transplanted cells. The aim of this thesis was to assess whether the properties of three-dimensional polymer matrices in synthetic biomaterial such as polylactic acid and in natural origin as silk fibroin, if and how influence differentiative process of stem cells cardiac c-kit +. Another point considered was been the evaluation of expression of cardiac markers and sarcomeric proteins of cells isolated, inoculated in different types of scaffold and maintained in colture for 21gg in vitro and analyzed in RT-PCR and Real-time quantitative RT–PCR analysis. Also it was analyzed the immunogenicity of the scaffold when implanted in the dorsal subcutaneous region of nude mice, nude rats and SCID mice in order a possible use in vivo in the cardiac regeneration. These experiments showed a myocardial-like differentiation, in which the CSCs acquired a muscle-like shape, with the formation of initial intercalated disks, and a striated-like myofilament organization. In results shown below highlights evidence of an higher degree of differentiation using 3D scaffold for CSCs c-Kit+ that can be induced to differentiate definitely into cardiomyocytes thanks to three-dimensional culture of the scaffold, where is possible an environment similar to a cardiac niche in vivo.