Transport viable heart tissue at physiological temperature yielded higher human cardiomyocytes compared to the conventional temperature.

This study investigated the optimum transport condition for heart tissue to recover single-cell cardiomyocytes for future in-vitro or in-vivo studies. The heart tissues were obtained from removing excessive myocardium discharged during the repair surgery of an excessive right atrial hypertrophy due to a congenital disease. The transportation temperature studied was the most used temperature (4 °C) or the conventional condition, compared to a physiological temperature(37 °C). The heart tissues were transported from the operating theatre to the lab maintained less than 30 min consistently. Single-cell isolation was enzymatically and mechanically performed using collagenase-V (160 U/mg) and proteinase-XXIV (7-14 U/mg) following the previously described protocol. The impact of temperature differences was observed by the density of cells harvested per mg tissue, cell viability, and the senescence signals, identified by the p21, p53 and caspase-9 mRNA expressions. Results the heart tissue transported at 37 °C yielded significantly higher viable cell density (p < 0.01) yielded viable cells significantly higher density (p < 0.01) than the 4 °C; 2,335 ± 849 cells per mg tissue, and 732 ± 425 cells per mg tissue, respectively. The percentage of viable cells in both groups showed no difference. Although the 37 °C group expressed the apoptosis genes such as p21, p53 and caspase9 by 2.5-, 5.41-, 5-fold respectively (p > 0.05). Nonetheless, the Nk×2.5 and MHC genes were expressed 1,7- and 3.56-fold higher than the 4 °C. and the c-Kit+ expression was 17.56-fold, however, statistically insignificant. Conclusion When needed for single-cell isolation, a heart tissue transported at 37 °C yielded higher cell density per mg tissue compared to at 4 °C, while other indicators of gene expressions for apoptosis, cardiac structural proteins, cardiac progenitor cells showed no difference. Further investigations of the isolated cells at different temperature conditions towards their proliferation and differentiation capacities in a 3-D scaffold would be essential.