Both the transplantation of somatic cell nuclear transfer- and fertilization-derived mouse embryonic stem cells with temperature-responsive chitosan hydrogel improve myocardial performance in infarcted rat hearts.

The transplantation of embryonic stem cells could improve cardiac function but was limited by immune rejection as well as low cell retention and survival within the ischemic tissues. The somatic cell nuclear transfer (SCNT) is practical to generate autologous histocompatible stem (nuclear-transferred embryonic stem [NTES]) cells for diseases, but NTES may be arguably unsafe for therapeutic application. The temperature-responsive chitosan hydrogel is a suitable matrix in cell transplantation. As the scaffold, chitosan hydrogel was coinjected with NTES cells into the left ventricular wall of rat infarction models. Detailed histological analysis and echocardiography were performed to determine the structure and functional consequences of transplantation. The myocardial performance in SCNT- and fertilization-derived mouse ES cell transplantation with chitosan hydrogel was also compared. The results showed that both the 24-h cell retention and 4-week graft size were significantly greater in the NTES + chitosan group than that of NTES + phosphate-buffered saline (PBS) group (p < 0.01). The NTES cells might differentiate into cardiomyocytes in vivo. The heart function improved significantly in the chitosan + NTES group (fractional shortening: 28.7% +/- 2.8%) compared with that of PBS + NTES group (fractional shortening: 25.2% +/- 2.9%) at 4 weeks after transplantation (p < 0.01). In addition, the arteriole/venule densities within the infarcted area improved significantly in the chitosan + NTES group (280 +/- 17/mm(2)) compared with that of PBS + NTES group (234 +/- 16/mm(2)) at 4 weeks after transplantation (p < 0.01). There was no difference in the myocardial performance in SCNT- and fertilization-derived mouse ES cell transplantation with chitosan hydrogel. The NTES cells with chitosan hydrogel have been proved to possess therapeutic potential to improve the function of infarcted heart. Thus the method of in situ injectable tissue engineering is promising clinically.