Cardiac differentiation of bone-marrow-resident c-kit+ stem cells by L-carnitine increases through secretion of VEGF, IL6, IGF-1, and TGF- β as clinical agents in cardiac regeneration.

The idea of regenerating lost myocardium via cell-based therapies remains as highly considerable. C-kit? stem/ progenitor cells are represented to be suitable candidates for cardiac regeneration compared to other stem cells. A multitude of cytokines from these cells are known to give such multifunctional properties; however, the associated mechanisms of these factors are yet to be totally understood. The aim of the present study was to investigate the in vitro effect of L-carnitine (LC) on cardiac differentiation of c-kit+ cells using a cytokines secretion assay. For this purpose, bone-marrow-resident-c-kit+ cells were enriched by MACS method, and were differentiated to cardiac cells using cardiomyocyte differentiation medium in the absence (control group) and presence of LC (experimental group). Also, characterization of enriched c-kit+ cells was performed using flow cytometry and immunocytochemistry. In the following, the cells were subjected to real-time PCR and Western blotting assay for gene and protein assessment, respectively. Afterward, culture medium was collected from both control (-LC) and experimental groups (+ LC) for cytokine measurement. It was found that 0.2 mM LC significantly increased the mRNA and protein expression of cardiac markers of Ang-1, Ang-2, C-TnI, VEGF, vWF, and SMA in c-kit+-cardiomyogenic-differentiated cells. Also, the significant presence of IL-6, IGF-1, TGF- β and VEGF were obvious in the cultured media from the experimental group compared with the control group. It can be concluded that the mentioned in vitro effects of LC on cardiac differentiation of c-kit+ cells could have resulted from the secreted cytokines IL-6, IGF-1, TGF- β and VEGF.