Inhibition of NADPH oxidase reduces myocardial oxidative stress and apoptosis and improves cardiac function in heart failure after myocardial infarction.
Increases in NADPH oxidase activity, oxidative stress, and myocyte apoptosis coexist in failing hearts. In cardiac myocytes in vitro inhibition of NADPH oxidase reduces apoptosis. In this study, we tested the hypothesis that NADPH oxidase inhibition reduces myocyte apoptosis and improves cardiac function in heart failure after myocardial infarction (MI). Rabbits with heart failure induced by MI and sham-operated animals were randomized to orally receive apocynin, an inhibitor of NADPH oxidase (15 mg per day) or placebo for 4 weeks. Left ventricular (LV) dimension and function were assessed by echocardiography and hemodynamics. Myocardial NADPH oxidase activity was measured by superoxide dismutase-inhibitable cytochrome c reduction assay, NADPH oxidase subunit p47phox expression by Western blot and immunofluorescence analysis, myocardial oxidative stress evaluated by 8-hydroxydeoxyguanosine (8-OHdG) and 4-hydroxy-2-nonenal (4-HNE) using immunohistochemistry, and myocyte apoptosis by TUNEL assay. MI rabbits exhibited LV dilatation and systolic dysfunction measured by LV fractional shortening and the maximal rate of LV pressure rise (dP/dt). These changes were associated with increases in NADPH oxidase activity, p47phox protein expression, 8-OHdG expression, 4-HNE expression, myocyte apoptosis, and Bax protein and a decrease in Bcl-2 protein. Apocynin reduced NADPH oxidase activity, p47phox protein, oxidative stress, myocyte apoptosis, and Bax protein, increased Bcl-2 protein, and ameliorated LV dilatation and dysfunction after MI. The results suggest that inhibition of NADPH oxidase may represent an attractive therapeutic approach to treat heart failure.
Qin
Fuzhong
F
Cardiology Unit, Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA. fqin@bu.edu
Simeone
Megan
M
Patel
Ravish
R
D000098:Acetophenones / Q000627:therapeutic use*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D017209:Apoptosis; D001794:Blood Pressure; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D006321:Heart / Q000502:physiology*; D006333:Heart Failure / Q000188:drug therapy*; D006801:Humans; D009203:Myocardial Infarction / Q000188:drug therapy*; D009206:Myocardium / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000473:pathology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009929:Organ Size; D018384:Oxidative Stress / Q000502:physiology*; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism
D000098:Acetophenones; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; C056165:acetovanillone; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1