Abstract 648: Heme-oxygenase-1 Gene Expression Ameliorates Cardiac Dysfunction Following Myocardial Infarction In C57 Mice By Recruitment Of Angiogenic Factors And Angiogenesis In C57 Mice
Rational: Angiogenesis is essential in order to increase blood circulation in infarcted tissue of MI (Myocardial infarction). Increased Heme-Oxygenase (HO)-1 gene expression increases angiogenic proteins, e.g. VEGF, bFGF, EGF, angiopoietin and adiponectin.
Objective: To investigate whether increased levels of HO-1, after the occurrence of a MI, improves angiogenesis and capillary formation in ischemic myocardium, thereby improving cardiac function.
METHODS: Experimental MI was induced by LAD (Left anterior descending artery) ligation. C57BL6 mice were divided into 4 groups: Sham; MI; 5 days after MI treated with the HO-1 inducer, cobalt protoporphyrinIX (CoPP); and, CoPP in the presence of the HO activity inhibitor, Stannous Mesoporphyrin (SnMP). HO-1 downstream signaling proteins were determined including VEGF, CD31 and adiponectin. Echocardiography was performed weekly for 4 weeks after surgery.
Results: 5 days after MI, CoPP treatment significantly increased VEGF (p<0.05 vs.MI), CD31 (p<0.05 vs.MI), and adiponectin levels (p<0.05 vs.MI). These findings were associated with a significant increase in capillary formation and blood flow in CoPP-treated animals (p<0.05 vs.MI). Echocardiography showed that left ventricle dilatation, measured as end diastolic area (EDA), was significantly reduced in CoPP- treated animals compared to MI groups (EDA: MI: 0.216±0.02cm2; MI+CoPP: 0.172±0.03 cm2; (-13%) p<0.01). This was associated with a significant decrease in apoptosis and fibrosis (P<0.05). These beneficial effects were reversed by SnMP administration.
Conclusion: HO-1 improved cardiac function and enhanced angiogenesis via the recruitment of pro-angiogenic factors.
- © 2012 by American Heart Association, Inc.