Characterization of Decellularized Heart Matrices as Biomaterials for Regular and Whole Organ Tissue Engineering and Initial In-vitro Recellularization with Ips Cells.

Tissue engineering strategies, based on solid/porous scaffolds, suffer from several limitations, such as ineffective vascularization, poor cell distribution and organization within scaffold, in addition to low final cell density, among others. Therefore, the search for other tissue engineering approaches constitutes an active area of investigation. Decellularized matrices (DM) present major advantages compared to solid scaffolds, such as ideal chemical composition, the preservation of vascularization structure and perfect three-dimensional structure. In the present study, we aimed to characterize and investigate murine heart decellularized matrices as biomaterials for regular and whole organ tissue engineering. Heart decellularized matrices were characterized according to: 1. DNA content, through DNA quantificationo and PCR of isolated genomic DNA; 2. Histological structure, assessed after Hematoxylin and Eosin, as well as Masson's Trichrome stainings; 3. Surface nanostructure analysis, performed, using SEM. Those essays allowed us to conclude that DM was indeed decellularized, with preserved extracellular matrix structure. Following characterization, decellularized heart slices were seeded with induced Pluripotent Stem cells (iPS). As expected, but - to the best of our knowledge - never shown before, decellularization of murine heart matrices maintained matrix biocompatibility, as iPS cells rapidly attached to the surface of the material and proliferated. Strikingly though, heart DM presented a differentiation induction effect over those cells, which lost their pluripotency markers after 7 days of culture in the DM. Such loss of differentiation markers was observed, even though bFGF containing media mTSR was used during such period. Gene expression of iPS cells cultured on DM will be further analyzed, in order to assess the effects of culturing pluripotent stem cells in decellularized heart matrices.