In Vitro Produced Cardiac Extracellular Matrix for Studies of Myocardium Regeneration Potential

The essential requirement for a successful myocardial tissue engineering is that scaffolds and tissue constructs exhibit biomimetic activity toward cells. Our aim was to investigate the significance of cell-matrix interactions in cardiac tissue microenvironment in vitro. Cardiac fibroblasts from normal (CF-N) and pathological (CF-P) hearts with ischemic cardiopathy deposited extracellular matrix (Mx) and conditioned medium (Cm), which were then characterized by immunohistology, immunoblotting, ELISA-based protein array or mass spectrometry. Normal and pathological cardiac primitive cells CPC-N and -P) were cultured on CF-Mx-N and -P or in CF-Cm-N and -P and their proliferation, apoptosis, migration and maturation were evaluated by BrdU, TdT, scratch wound assays or RT-PCR, respectively. Laminin-1 and tenascin-X were detected in CF-Mx-P. The expression of IGFBP1, Il-6, EGF was higher in CF-Cm-P, while that of SCF, TGF-?3, BMP4 was higher in CF-Cm-N. Migration speed of CPC-P peaked at 21.3 ?m/h on CF-Mx-N. Proliferation of CPCs increased significantly on CF-Mx-P, while apoptosis diminished on both types of matrix. In CPC-N, maturation toward cardiomyocytes was activated by CF Mx-N and toward endothelial cells by CF-Mx-P; in CPC-P the trend toward smooth muscle cell-lineage was evident on both substrates. CF-Cm-N reduced apoptosis of CPC-N (2-fold), while CF-Cm-P reduced apoptosis of CPC-P (3.5-fold) and increased proliferation of CPC-N (1.6-fold, n=3, p<0.05). These results highlight the influence of microenvironment on cardiac regeneration. Changes that take place in pathological conditions should be taken into consideration when planning cell-based therapy and scaffold functionalization.