5-nitro-γ-tocopherol increases in human plasma exposed to cigarette smoke in vitro and in vivo

Scott W. Leonard, Richard S. Bruno, Elaine Paterson, Bettina C. Schock, Jeffery Atkinson, Tammy M. Bray, Carroll E Cross, Maret G. Traber

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

We hypothesized that the high concentrations of reactive nitrogen species in cigarette smoke and the known stimulatory effects of cigarette smoke on the inflammatory immune systems would lead to the formation of 5-nitro-γ- tocopherol (NGT). In order to assess γ-tocopherol nitration, human plasma was exposed in vitro to gas phase cigarette smoke (GPCS) or air for up to 6 h. A liquid chromatography-mass spectrometry (LC-MS) method was developed to quantitate NGT. Detector response was linear from 0.1 to 3 pmol NGT, with a detection limit of 20 fmol. After a 1 h lag time, 6 h plasma exposure to GPCS depleted ∼ 75% of α-T, ∼ 60% of γ-T and increased NGT from 3 to 134 nmol/l. The increase in NGT accounted for ∼ 20% of the γ-T decrease. NGT also correlated (R2 = 0.9043) with nitrate concentrations in GPCS-exposed plasma. The physiologic relevance of NGT was evaluated in a group of healthy humans. Smokers (n = 15) had plasma NGT concentrations double those of nonsmokers (n = 19), regardless of corrections using lipids or γ-T; plasma α-T and γ-T concentrations were similar between the groups. Our results show that LC-MS can be successfully used for NGT quantitation in biologic samples. Importantly, NGT in smokers' plasma suggests that cigarette smoking causes increased nitrosative stress.

Original languageEnglish (US)
Pages (from-to)1560-1567
Number of pages8
JournalFree Radical Biology and Medicine
Volume35
Issue number12
DOIs
StatePublished - Dec 15 2003

Keywords

  • γ-Tocopherol
  • Cigarette smoke
  • Free radicals
  • Oxidative stress

ASJC Scopus subject areas

  • Medicine(all)
  • Toxicology
  • Clinical Biochemistry

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    Leonard, S. W., Bruno, R. S., Paterson, E., Schock, B. C., Atkinson, J., Bray, T. M., Cross, C. E., & Traber, M. G. (2003). 5-nitro-γ-tocopherol increases in human plasma exposed to cigarette smoke in vitro and in vivo. Free Radical Biology and Medicine, 35(12), 1560-1567. https://doi.org/10.1016/j.freeradbiomed.2003.09.010