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TRANSLATIONAL PHYSIOLOGY

Role of TNF--induced reactive oxygen species in endothelial dysfunction during reperfusion injury

¹Departments of Internal Medicine, Medical Physiology and Pharmacology, and Nutritional Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; ²Department of Physiology, Louisiana State University, Health Sciences Center, New Orleans, Louisiana; and ³Molecules For Health, Richmond, Virginia

Submitted 4 June 2008 ; accepted in final form 17 September 2008

We hypothesized that neutralization of TNF- at the time of reperfusion exerts a salubrious role on endothelial function and reduces the production of reactive oxygen species. We employed a mouse model of myocardial ischemia-reperfusion (I/R, 30 min/90 min) and administered TNF- neutralizing antibodies at the time of reperfusion. I/R elevated TNF- expression (mRNA and protein), whereas administration of anti-TNF- before reperfusion attenuated TNF- expression. We detected TNF- expression in vascular smooth muscle cells, mast cells, and macrophages, but not in the endothelial cells. I/R induced endothelial dysfunction and superoxide production. Administration of anti-TNF- at the onset of reperfusion partially restored nitric oxide-mediated coronary arteriolar dilation and reduced superoxide production. I/R increased the activity of NAD(P)H oxidase and of xanthine oxidase and enhanced the formation of nitrotyrosine residues in untreated mice compared with shams. Administration of anti-TNF- before reperfusion blocked the increase in activity of these enzymes. Inhibition of xanthine oxidase (allopurinol) or NAD(P)H oxidase (apocynin) improved endothelium-dependent dilation and reduced superoxide production in isolated coronary arterioles following I/R. Interestingly, I/R enhanced superoxide generation and reduced endothelial function in neutropenic animals and in mice treated with a neutrophil NAD(P)H oxidase inhibitor, indicating that the effects of TNF- are not through neutrophil activation. We conclude that myocardial ischemia initiates TNF- expression, which induces vascular oxidative stress, independent of neutrophil activation, and leads to coronary endothelial dysfunction.

coronary disease; endothelium; free radicals; microcirculation; nitric oxide

This article has been cited by other articles:

				W. N. Duran The double-edge sword of TNF-{alpha} in ischemia-reperfusion injury Am J Physiol Heart Circ Physiol, December 1, 2008; 295(6): H2221 - H2222. [Full Text] [PDF]