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Endothelial dysfunction and body mass index: is there a role for plasma peroxynitrite?

Authors
  • Chikopela, Theresa1
  • Heimburger, Douglas C.2, 3
  • Kaluba, Longa4
  • Hamambulu, Pharaoh1
  • Simfukwe, Newton3
  • Mutale, Wilbroad3
  • Koethe, John R.2
  • Goma, Fastone3
  • 1 Lusaka Apex Medical University, Lusaka, Zambia , Lusaka (Zambia)
  • 2 Vanderbilt University Medical Center, Nashville, TN, USA , Nashville (United States)
  • 3 University of Zambia, Lusaka, Zambia , Lusaka (Zambia)
  • 4 Cavendish University, Lusaka, Zambia , Lusaka (Zambia)
Type
Published Article
Journal
Beni-Suef University Journal of Basic and Applied Sciences
Publisher
Springer Berlin Heidelberg
Publication Date
Jan 14, 2021
Volume
10
Issue
1
Identifiers
DOI: 10.1186/s43088-020-00092-6
Source
Springer Nature
Keywords
License
Green

Abstract

BackgroundEndothelial function is dependent on the balance between vasoconstrictive and vasodilatory substances. The endothelium ability to produce nitric oxide is one of the most crucial mechanisms in regulating vascular tone. An increase in inducible nitric oxide synthase contributes to endothelial dysfunction in overweight persons, while oxidative stress contributes to the conversion of nitric oxide to peroxynitrite (measured as nitrotyrosine in vivo) in underweight persons. The objective of this study was to elucidate the interaction of body composition and oxidative stress on vascular function and peroxynitrite. This was done through an experimental design with three weight groups (underweight, normal weight and overweight), with four treatment arms in each. Plasma nitrotyrosine levels were measured 15–20 h post lipopolysaccharide (LPS) treatment, as were aortic ring tension changes. Acetylcholine (ACh) and sodium nitroprusside (SNP) challenges were used to observe endothelial-dependent and endothelial-independent vascular relaxation after pre-constriction of aortic rings with phenylephrine.ResultsNitrotyrosine levels in saline-treated rats were similar among the weight groups. There was a significant increase in nitrotyrosine levels between saline-treated rats and those treated with the highest lipopolysaccharide doses in each of the weight groups. In response to ACh challenge, Rmax (percentage reduction in aortic tension) was lowest in overweight rats (112%). In response to SNP, there was an insignificantly lower Rmax in the underweight rats (106%) compared to the normal weight rats (112%). Overweight rats had a significant decrease in Rmax (83%) in response to SNP, signifying involvement of a more chronic process in tension reduction changes. A lower Rmax accompanied an increase in peroxynitrite after acetylcholine challenge in all weight groups.ConclusionsEndothelial dysfunction, observed as an impairment in the ability to reduce tension, is associated with increased plasma peroxynitrite levels across the spectrum of body mass. In higher-BMI rats, an additional role is played by vascular smooth muscle in the causation of endothelial dysfunction.

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