Amine-enriched surface modification facilitates expansion, attachment, and maintenance of human cardiac-derived c-kit positive progenitor cells.

BACKGROUND: Stem cells have a low expansion rate and are difficult to maintain in vitro. To overcome the problems of cardiovascular regeneration, we developed a novel method of stem cell cultivation in culture vessels with amine and carboxyl coatings. METHODS AND RESULTS: We isolated cardiac stem/progenitor cells from infant-derived heart tissue by using c-kit antibody (human cardiac-derived c-kit positive progenitor cells; hCPC(c-kit+)); the cells differentiated into endothelial cells, smooth muscle cells, and cardiomyocytes. To characterize the effect of surface modification on hCPC(c-kit+) expansion, cellular attachment, c-kit expression maintenance, and cardiomyocyte differentiation, we tested hCPC(c-kit+) cultured on non-coated (control), amine-coated (amine), and carboxyl-coated (carboxyl) vessels. Ex vivo proliferation, c-kit maintenance, and cellular attachment were significantly enhanced in the amine group. The amine coating also increased procollagen type I (pro-COL1) expression and increased phosphorylation signals, such as focal adhesion kinase (FAK) and cytosolic Src, as well as enhanced ERK/CDK2 signaling. In addition, there was significant downregulation of the stress signal transducer, JNK, in the amine group. However, cardiomyogenesis remained unchanged in the control, amine, and carboxyl groups. CONCLUSIONS: Although surface modifications had no effect on early induction cardiomyogenesis, amine-enriched surface modification may increase hCPC(c-kit+) expansion. The amine-enriched surface improved cellular proliferation and attachment during ex vivo hCPC(c-kit+) expansion, possibly by modulating intracellular signal transducers.