Few reports have examined the effects of adult bone marrow multipotent stromal cells (MSCs) on large animals, and no useful method has been established for MSC implantation. In this study, we investigate the effects of MSC infusion from the coronary vein in a swine model of chronic myocardial infarction (MI). MI was induced in domestic swine by placing beads in the left coronary artery. Bone marrow cells were aspirated and then cultured to isolate the MSCs. At 4 weeks after MI, MSCs labeled with dye (n ¼ 8) or vehicle (n ¼ 5) were infused retrogradely from the anterior interventricular vein without any complications. Left ventriculography (LVG) was performed just before and at 4 weeks after cell infusion. The ejection fraction (EF) assessed by LVG significantly decreased from baseline up to a follow-up at 4 weeks in the control group (Po0.05), whereas the cardiac function was preserved in the MSC group. The difference in the EF between baseline and follow-up was significantly greater in the MSC group than in the control group (Po0.05). The MSC administration significantly promoted neovascularization in the border areas compared with the controls (Po0.0005), though it had no affect on cardiac fibrosis. A few MSCs expressed von Willebrand factor in a differentiation assay, but none of them expressed troponin T. In quantitative gene expression analysis, basic fibroblast growth factor and vascular endothelial growth factor (VEGF) levels were significantly higher in the MSC-treated hearts than in the controls (Po0.05, respectively). Immunohistochemical staining revealed VEGF production in the engrafted MSCs. In vitro experiment demonstrated that MSCs significantly stimulated endothelial capillary network formation compared with the VEGF protein (Po0.0001). MSC infusion via the coronary vein prevented the progression of cardiac dysfunction in chronic MI. This favorable effect appeared to derive not from cell differentiation, but from enhanced neovascularization by angiogenic factors secreted from the MSCs.
SUMMARYAlthough angiotensin-converting enzyme inhibitors (ACEIs) have been shown to reduce left ventricular remodeling after acute myocardial infarction (AMI), the effects of angiotensin receptor blockers have yet to be established. This study was conducted to examine the effects of candesartan on left ventricular remodeling after AMI. Consecutive AMI patients were assigned to a candesartan group or ACEI group after successful coronary intervention. The patients in the candesartan group (n = 77, mean age, 62.8 ± 1.3) received candesartan and the patients in the ACEI group (n = 80, mean age, 63.3 ± 1.2) received lisinopril, enalapril, or trandolapril. Four mg was the most frequent dose in the candesartan group at 6 months. Lisinopril, enalapril, and trandolapril were administered to 52%, 27%, and 21% of the patients in the ACEI group, respectively. No significant differences in the incidences of cardiac death, nonfatal MI, or hospitalization for heart failure (P = NS) were found between the groups. The candesartan group exhibited a somewhat higher percent increase in left ventricular ejection fraction and significantly lower percent increases in left ventricular end-diastolic volume index and left ventricular end-systolic volume index compared to the ACEI group (P < 0.05, P < 0.05, respectively). Candesartan is more effective than ACEI in preventing left ventricular remodeling after AMI. (Int Heart J 2006; 47: 715-725) Key words: Myocardial remodeling, Angiotensin receptor blocker, Angiotensin-converting enzyme inhibitor IN-hospital mortality in acute myocardial infarction (AMI) has been reduced to less than 10% due to ongoing advances in coronary care and coronary interventional therapies. Even so, left ventricular remodeling after AMI still limits the long-term prognosis and remains an important predictor of mortality.1,2) Early and successful coronary intervention not only limits the amount of muscle necrosis but also protects cardiac collagen, 3) however, we sometimes encounter AMI From the
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