BACKGROUND:Autologous stem celltransplantation to the heart is a research direction of heart failure treatment, but there are relatively few of studies about autologous bone marrow mesenchymal stem celltransplantation targeting the cardiac conduction system. OBJECTIVE:To evaluate the potential of rabbit bone marrow mesenchymal stem cells for treatment of heart block. METHODS:Rabbit bone marrow mesenchymal stem cells were induced by 5-azacytidine to differentiate into cardiomyocyte-like cells. After thoracotomy, the left atrium-left ventricular anterior wal was sutured in 14 New Zealand white rabbits (8 in the experimental group and 6 in the control group). One month after the surgery, in the experimental group, autologous bone marrow mesenchymal stem cells induced by 5-azacytidine for 4 weeks were labeled with 4',6-diamidino-2-phenylindole and then injected into the suture area when opening the thoracic again. In the control group, cells cultured in medium were used. One month after celltransplantation, the third thoracotomy was done to insert electrodes into the left atrium and left ventricular anterior wal , for cardiac electrophysiological detection. Whether atrioventricular pathway formed in the suture area was observed. RESULTS AND CONCLUSION:After cells were transplanted into the sutured area, two rabbits in the experimental group were discovered to form the atrioventricular pathway in the sutured area through cardiac electrophysiological examination. After transplantation, transplanted cells were visible on the heart frozen sections under fluorescence microscope in the left ventricle and sutured area, but there was no cellin the control group. In the experimental group, bone marrow mesenchymal stem cells expressed Cx43 and formed gap junction intercellular communication with cardiomyocytes, which was presented as formation of the atrioventricular pathway on cardiac electrophysiology examination. These findings indicate that bone marrow mesenchymal stem cells can be used to treat cardiac conduction system block diseases.

Objective To investigate the effect of super-selective intracoronary administration on acute myocardial in farction patients.Methods A total of 240 patients with ST-segment elevation myocardial infarction who received emergency percutaneous coronary intervention in our department from March 2012 to January 2014 were selected and divided into the intravenous drug administration group (n=77),the conventional intracoronary drug administration group (n=81) and the super-selective intracoronary drug administration group (n=82).Parameters,including the Thrombolysis in Myocardial Infarction (TIMI) classification,ST segment resolution after operation,peak values of creatine kinase MB (CK-MB) and troponin-I (cTn-I),left ventricular ejection fraction,left ventricular end-diastolic diameter (LVEDD),major adverse cardiovascular events and bleeding events,were compared between the groups.Results There were no significant differences in TIMI flow grade between the three groups (x2 =0.14,P=0.529).The percentage of patients with complete ST segment resolution after operation was higher in the super-selective intracoronary drug administration group than in the intravenous drug administration and conventional intracoronary drug administration groups (74.4％ vs.62.3％,61.7％,x2 =8.24,P＜0.05).Peak values of CK-MB and cTn-I were lower in the super-selective intracoronary drug administration group than in the other groups (P＜0.05).There were no significant differences in left ventricular ejection fraction and LVEDD between the three groups after operation,but left ventricular ejection fraction and the incidence of angina pectoris significantly improved in the super-selective intracoronary drug administration group than in the other groups after a three month follow-up (P＜0.05).There were no significant differences in target lesion revascularization,nonfatal myocardial infarction and druginduced thrombocytopenia between the three groups (P ＞ 0.05).Conclusions Super-selective intracoronary drug administration can significantly enhance cardiac function and alleviate angina pectoris in patients with acute myocardial infarction,and should be a recommended method.