Early determinants of H2O2-induced endothelial dysfunction

Beth M. Boulden, Julian D. Widder, Jon C. Allen, Debra A. Smith, Ruaa N. Al-Baldawi, David G. Harrison, Sergey I. Dikalov, Hanjoong Jo, Samuel C. Dudley

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Reactive oxygen species (ROS) can stimulate nitric oxide (NO{radical dot}) production from the endothelium by transient activation of endothelial nitric oxide synthase (eNOS). With continued or repeated exposure, NO{radical dot} production is reduced, however. We investigated the early determinants of this decrease in NO{radical dot} production. Following an initial H2O2 exposure, endothelial cells responded by increasing NO{radical dot} production measured electrochemically. NO{radical dot} concentrations peaked by 10 min with a slow reduction over 30 min. The decrease in NO{radical dot} at 30 min was associated with a 2.7-fold increase in O2{radical dot}- production (p < 0.05) and a 14-fold reduction of the eNOS cofactor, tetrahydrobiopterin (BH4, p < 0.05). Used as a probe for endothelial dysfunction, the integrated NO{radical dot} production over 30 min upon repeated H2O2 exposure was attenuated by 2.1-fold (p = 0.03). Endothelial dysfunction could be prevented by BH4 cofactor supplementation, by scavenging O2{radical dot}- or peroxynitrite (ONOO-), or by inhibiting the NADPH oxidase. Hydroxyl radical ({radical dot}OH) scavenging did not have an effect. In summary, early H2O2-induced endothelial dysfunction was associated with a decreased BH4 level and increased O2{radical dot}- production. Dysfunction required O2{radical dot}-, ONOO-, or a functional NADPH oxidase. Repeated activation of the NADPH oxidase by ROS may act as a feed forward system to promote endothelial dysfunction.

Original languageEnglish (US)
Pages (from-to)810-817
Number of pages8
JournalFree Radical Biology and Medicine
Issue number5
StatePublished - Sep 1 2006

Bibliographical note

Funding Information:
This study was supported by National Institutes of Health (NIH) Grants HL64828 and HL73753 (S.C.D.), Department of Veterans Affairs Merit grant (S.C.D.), and an American Heart Association Established Investigator Award (S.C.D.). Dr. Widder was supported by the Deutsche Akademie der Naturforscher Leopoldina (BMBF-LPD 9901/8-97).


  • Electrochemistry [H01.181.529.307]
  • Endothelium [A10.272.491]
  • Hydrogen peroxide [D01.248.497.158.685.750.424]
  • Nitric oxide [D01.339.387]
  • Nitric oxide synthase [D08.811.682.135.772]


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