Delayed enrichment for c-kit and inducing cardiac differentiation attenuated protective effects of BMSCs' transplantation in pig model of acute myocardial ischemia.
OBJECTIVE
To investigate the effects of immature cardiomyocytes differentiated from c-kit(+) bone marrow mesenchymal stem cells (BMSCs) against acute myocardial infarction (AMI).


METHODS
Miniswine passage 8 BMSCs were enriched for c-kit and induced by 5 μM 5-azacytidine (AZA) for 14 days, and a second enrichment for the dihydropyridine receptor subunit α2δ1 was performed (enriched BMSCs). Thereafter, enriched BMSCs were analyzed by determining cardiac differentiation, secretion function, and the effects of these secreted factors on cardiac stem cells (CSCs). Miniswine with AMI were divided into control, primary BMSCs' (PB), and enriched BMSCs' (EB) groups. Autologous BMSCs were intramyocardially injected into the ischemic regions in PB and EB groups. The following indices were evaluated at different time points, including paracrine of implanted BMSCs, histological and morphological analysis, myocardial perfusion, and cardiac function.


RESULTS
As shown by in vitro study, enrichment + AZA significantly promoted BMSCs to express cardiac-specific markers and format action potential, but down-regulated the expression of VEGF and bFGF, consequently attenuated BMSCs-inducing CSCs proliferation, migration, and differentiation. The in vivo experiments revealed similar results like the in vitro 6 weeks postoperatively. And in EB group, there were decreased angiogenesis and myocardial perfusion, attenuated resident CSCs-mediated myocardial regeneration, and consequently impaired cardiac function compared with PB group.


CONCLUSIONS
This pretreatment promoted BMSCs to differentiate into myocardiocytes both in vitro and in vivo, but impaired their paracrine function and effects on resident CSCs, suggesting that inducing cardiac differentiation alone may not improve protective effects of BMSCs transplantation on AMI.
['Zhang|Guang-Wei|GW|', 'Gu|Tian-Xiang|TX|', 'Guan|Xiao-Yu|XY|', 'Sun|Xue-Jun|XJ|', 'Jiang|Da-Qing|DQ|', 'Tang|Rui|R|', 'Qi|Xun|X|', 'Li|Xue-Yuan|XY|']
D000818:Animals D001374:Azacitidine D020746:Calcium Channels, L-Type D002454:Cell Differentiation D002478:Cells, Cultured D003326:Coronary Circulation D004195:Disease Models, Animal D016222:Fibroblast Growth Factor 2 D045164:Mesenchymal Stem Cell Transplantation D059630:Mesenchymal Stem Cells D009203:Myocardial Infarction D009206:Myocardium D032383:Myocytes, Cardiac D018919:Neovascularization, Physiologic D019899:Paracrine Communication D010641:Phenotype D019009:Proto-Oncogene Proteins c-kit D012038:Regeneration D013552:Swine D013556:Swine, Miniature D013997:Time Factors D042461:Vascular Endothelial Growth Factor A D016277:Ventricular Function, Left D014841:von Willebrand Factor
myocardial infarction regeneration Cell differentiation stem cell transplantation ventricular function