Abstract
We isolated cardiac stem cells （CSCs）, named CSC-4A, from adult rats that revealed high GATA4 expression levels. When the primary cardiomyocytes from the adult rat heart were co-cultured with CSC-4A with or without inserts （the filter that separates these two types of cells to avoid direct contact）, the cardiomyocytes sustained the contraction compared with the cardiomyocytes cultured alone or those cultured with fibroblasts or GATA4 low CSCs. The medium from the co-cultures of CSC-4A and cardiomyocytes contained higher IGF-1 concentrations. CSC-4A did not release IGF-1 or expressed IGF-1 mRNA. Therefore, CSC-4A may express some soluble factors that enhance IGF-1 expression in co-cultured cardiomyocytes. Identification of such soluble factors would enable us to develop the appropriate drugs or regeneration materials or a combination of both, which are key to the development of more efficient regenerative medical tools in the future.
