Isoproterenol pre-treatment improve the therapeutic efficacy of cardiosphere-derived cells transplantation for myocardial infarction.

BACKGROUND: This study aimed to investigate the effect of isoproterenol pre-treatment on the therapeutic efficacy of cardiosphere-derived cells (CDCs) transplantation for myocardial infarction (MI).

METHODS: Thirty 8-week-old male Sprague-Dawley (SD) rat model of MI was generated by ligation of the left anterior descending artery. The MI rats were treated with PBS (MI group, n=8), CDCs (MI + CDC group, n=8) and isoproterenol pre-treated CDCs (MI + ISO-CDC group, n=8), respectively. In the MI + ISO-CDC group, CDCs were pre-treated by 10-6 M isoproterenol and the cultured for additional 72 h, then injected to the myocardial infraction area like other groups. At 3 weeks after the operation, echocardiographic, hemodynamic, histological assessments and Western blot were performed to compare the CDCs differentiation degree and therapeutic effect.

RESULTS: Isoproterenol treatment (10-6 M) simultaneously inhibited proliferation and induced apoptosis of CDCs, up-regulated proteins of vimentin, cTnT, α-sarcomeric actin and connexin 43, and down-regulated c-Kit proteins (all P<0.05). The echocardiographic and hemodynamic analysis demonstrated that the MI rats in the two CDCs transplantation groups had significantly better recovery of cardiac function than the MI group (all P<0.05). MI + ISO-CDC group had better recovery of cardiac function than the MI + CDC group, although the differences did not reach significant. Immunofluorescence staining showed that the MI + ISO-CDC group had more EdU-positive (proliferating) cells and cardiomyocytes in the infarct area than the MI + CDC group. MI + ISO-CDC group had significantly higher protein levels of c-Kit, CD31, cTnT, α-sarcomeric actin and α-SMA in the infarct area than the MI + CDC group.

CONCLUSIONS: These results suggested that in CDCs transplantation, isoproterenol pre-treated CDCs can provide a better protective effect against MI than the untreated CDCs.