Human C2a and C6a iPSC lines and H9 ESC line have less efficient cardiomyogenesis than H1 ESC line: Beating enhances cardiac differentiation.

BACKGROUND: Human induced pluripotent stem cells (hiPSCs) need to be thoroughly characterized to exploit their potential advantages in various aspects of biomedicine. The aim of this study was to compare the efficiency of cardiomyogenesis of two hiPSCs and two human embryonic stem cell (hESC) lines by genetic living cardiomyocyte labeling. We also analyzed the influence of spontaneous beating on cardiac differentiation. METHODS: H1 and H9 hESC lines and C2a and C6a hiPSC lines were induced into in vitro directed cardiac differentiation. Cardiomyogenesis was evaluated by the analysis of cell cluster beating, cardiac protein expression by immunocytochemistry, ability of cells to generate calcium transients, and cardiomyocyte quantification by the myosin light chain 2v-enhanced green fluorescent protein gene construct delivered with a lentiviral vector. RESULTS: Differentiation of all cell lines yielded spontaneously beating cell clusters, indicating the presence of functional cardiomyocytes. After the cell dissociation, H1-hESC-derived cardiomyocytes exhibited spontaneous calcium transients, corresponding to autonomous electrical activity and displayed ability to transmit them between the cells. Differentiated hESC and hiPSC cells exhibited striated sarcomeres and expressed cardiac proteins sarcomeric α-actinin and cardiac troponin T. Cardiomyocytes were the most abundant in differentiated H1 hESC line (20% more than in other tested lines). In all stem cell lines, cardiomyocyte enrichment was greater in beating than in non-beating cell clusters, irrespective of cardiomyogenesis efficiency. CONCLUSION: Although C2a and C6a hiPSC and H9 hESC lines exhibited efficient cardiomyogenesis, H1 hESC line yielded the greatest cardiomyocyte enrichment of all tested lines. Beating of cell clusters promotes cardiomyogenesis in tested hESCs and hiPSCs.

Peritumoral Clefting and Expression of MMP-2 and MMP-9 in Basal Cell Carcinoma of the Skin.

BACKGROUND/AIM: Peritumoral clefting is one of the main histologic features of basal cell carcinoma of the skin (BCC). The aim of the study was to analyze the expression of MMP-2 and MMP-9 both in cells of basal cell carcinoma and in the adjacent stroma and to correlate the findings of immunohistochemical analysis with the presence of peritumoral clefting. PATIENTS AND METHODS: The study was made on archival material comprising 48 cases of BCC. These were scanned for the presence of peritumoral clefts. The results of immunohistochemical staining for MMP-2 and MMP-9 were determined semiquantitatively using immunohistochemical staining index (ISI). RESULTS: Peritumoral retractions were found in 40 BCC cases. Positive immunohistochemical reaction for MMP-2 in tumor cells was found in 47 cases and in all cases in the adjacent stroma. Positive immunostaining for MMP-9 in BCC tumor cells was observed in 37 cases and in all cases in the adjacent stroma. There was no statistically significant association between peritumoral retractions and expression of MMPs. A statistically significant correlation was found in the expression of both MMP-2 and MMP-9 between the tumor and the stroma. CONCLUSION: Tumor cells elaborate MMP-2 and -9, but they also produce some other factors that may induce production of MMPs in adjacent stromal cells. The role of MMPs in the development of peritumoral clefts could not be confirmed.