on February 25, 2008
Published online before print February 25, 2008, doi: 10.1161/HYPERTENSIONAHA.107.103572
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Submitted on October 16, 2007
From the Departments of Internal Medicine (S.C., S.P.D., D.A.K., L.I.S., S.D., S.R.L., F.M.F.), and Pharmacology (F.M.F.), Cardiovascular Center, University of Iowa Carver College of Medicine, Iowa City; and the Veterans' Affairs Medical Center (S.R.L.), Iowa City, Iowa. * To whom correspondence should be addressed. E-mail: frank-faraci{at}uiowa.edu.
Abstract—Levels of reactive oxygen species, including hydrogen peroxide increase in blood vessels during hypertension and in response to angiotensin II (Ang II). Although glutathione peroxidases are known to metabolize hydrogen peroxide, the role of glutathione peroxidase during hypertension is poorly defined. We tested the hypothesis that glutathione peroxidase-1 protects against Ang II–induced endothelial dysfunction. Responses of carotid arteries from Gpx1-deficient (Gpx1+/- and Gpx1-/-) and Gpx1 transgenic mice, and their respective littermate controls, were examined in vitro after overnight incubation with either vehicle or Ang II. Under control conditions, relaxation to acetylcholine (ACh; an endothelium-dependent agonist) was similar in control, Gpx1+/-, and Gpx1 transgenic mice, whereas in Gpx1-/- mice, responses to ACh were impaired. In control mice, ACh-induced vasorelaxation was not affected by 1 nmol/L of Ang II. In contrast, relaxation to ACh in arteries from Gpx1+/- mice was inhibited by
Revised on November 6, 2007
Glutathione Peroxidase-1 Plays a Major Role in Protecting Against Angiotensin II–Induced Vascular Dysfunction
Sophocles Chrissobolis;
60% after treatment with 1 nmol/L of Ang II, indicating that Gpx1 haploinsufficiency markedly enhances Ang II–induced endothelial dysfunction. A higher concentration of Ang II (10 nmol/L) selectively impaired relaxation to ACh in arteries from control mice, and this effect was prevented in arteries from Gpx1 transgenic mice or in arteries from control mice treated with polyethylene glycol-catalase (which degrades hydrogen peroxide). Thus, genetic and pharmacological evidence suggests a major role for glutathione peroxidase-1 and hydrogen peroxide in Ang II–induced effects on vascular function.
Key words: oxidative stress • hydrogen peroxide • genetically altered mice • carotid arteries • endothelium
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Hypertension 2008 51: 825-826.
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