Abstract
Cyclooxygenase 2-selective inhibitors (coxibs) and nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with an increase in cardiovascular events. The current study was designed to test the effect of coxibs and nonselective NSAIDs on vascular superoxide and nitric oxide (NO) production. mRNA expression of endothelial NO synthase (eNOS) and of the vascular NADPH oxidases was studied in spontaneously hypertensive rats (SHR) and in human endothelial cells. The expression of Nox1, Nox2, Nox4, and p22phox was increased markedly by the nonselective NSAIDs diclofenac or naproxen and moderately by rofecoxib or celecoxib in the aorta and heart of SHR. The up-regulation of NADPH oxidases by NSAIDs was associated with increased superoxide content in aorta and heart, which could be prevented by the NADPH oxidase inhibitor apocynin. NSAIDs reduced plasma nitrite and diminished the phosphorylation of vasodilator-stimulated phosphoprotein. This demonstrates a reduction in vascular NO production. Aortas from diclofenac-treated SHR showed an enhanced protein nitrotyrosine accumulation, indicative of vascular peroxynitrite formation. Peroxynitrite can uncouple oxygen reduction from NO synthesis in eNOS. Accordingly, the eNOS inhibitor NG-nitro-l-arginine methyl ester reduced superoxide content in aortas of NSAID-treated animals, demonstrating eNOS uncoupling under those conditions. Also in human endothelial cells, NSAIDs increased Nox2 expression and diminished production of bioactive NO. In healthy volunteers, NSAID treatment reduced nitroglycerin-induced, NO-mediated vasodilatation of the brachial artery. These results indicate that NSAIDs may increase cardiovascular risk by inducing oxidative stress in the vasculature, with nonselective NSAIDs being even more critical than coxibs in this respect.
Footnotes
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This work was supported by the Collaborative Research Center SFB 553 (project A1 to H.L. and U.F.; project C17 to A.D. and T.M.) from the Deutsche Forschungsgemeinschaft, Bonn, Germany.
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H.L. and M.H. contributed equally to this work.
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This article contains parts of the doctoral thesis of M.H.: Hortmann M (2008) NSAIDs induzieren oxidativen stress in kardiovaskulären system. Doctoral dissertation, Johannes Gutenberg University, Mainz, Germany.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.108.139030.
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ABBREVIATIONS: NSAIDs, nonsteroidal anti-inflammatory drugs; COX, cyclooxygenase; coxibs, COX2-selective inhibitors; SHR, spontaneously hypertensive rat; ROS, reactive oxygen species; RT-PCR, reverse transcription-polymerase chain reaction; NOS, nitric-oxide synthase; eNOS, endothelial nitric-oxide synthase; l-NAME, NG-nitro-l-arginine methyl ester; L-012, 8-amino-5-chloro-7-phenylpyridol[3,4-d]pyridazine-1,4(2H,3H)dione; DHE, dihydroethidium; P-VASP, phosphorylated vasodilator-stimulated phosphoprotein; BH4,(6R)-5,6,7,8-tetrahydro-l-biopterin; VASP, vasodilator-stimulated phosphoprotein; iNOS, inducible NO synthase; cGK, cGMP-dependent protein kinase.
- Received March 14, 2008.
- Accepted June 5, 2008.
- The American Society for Pharmacology and Experimental Therapeutics
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