title: Endothelium-specific insulin resistance leads to accelerated atherosclerosis in areas with disturbed flow patterns: a role for reactive oxygen species.
abstract: OBJECTIVE
  Systemic insulin resistance is associated with a portfolio of risk factors for atherosclerosis development. We sought to determine whether insulin resistance specifically at the level of the endothelium promotes atherosclerosis and to examine the potential involvement of reactive oxygen species.
  
  
  METHODS
  We cross-bred mice expressing a dominant negative mutant human insulin receptor specifically in the endothelium (ESMIRO) with ApoE(-/-) mice to examine the effect of endothelium-specific insulin resistance on atherosclerosis.
  
  
  RESULTS
  ApoE(-/-)/ESMIRO mice had similar blood pressure, plasma lipids and whole-body glucose tolerance, but blunted endothelial insulin signalling, in comparison to ApoE(-/-) mice. Atherosclerosis was significantly increased in ApoE(-/-)/ESMIRO mice at the aortic sinus (226 ± 16 versus 149 ± 24 × 10(3) μm(2), P = 0.01) and lesser curvature of the aortic arch (12.4 ± 1.2% versus 9.4 ± 0.9%, P = 0.035). Relaxation to acetylcholine was blunted in aorta from ApoE(-/-)/ESMIRO mice (Emax 65 ± 41% versus 103 ± 6%, P = 0.02) and was restored by the superoxide dismutase mimetic MnTMPyP (Emax 112 ± 15% versus 65 ± 41%, P = 0.048). Basal generation of superoxide was increased 1.55 fold (P = 0.01) in endothelial cells from ApoE(-/-)/ESMIRO mice and was inhibited by the NADPH oxidase inhibitor gp91ds-tat (-12 ± 0.04%, P = 0.04), the NO synthase inhibitor L-NMMA (-8 ± 0.02%, P = 0.001) and the mitochondrial specific inhibitor rotenone (-23 ± 0.04%, P = 0.006).
  
  
  CONCLUSIONS
  Insulin resistance specifically at the level of the endothelium leads to acceleration of atherosclerosis in areas with disturbed flow patterns such as the aortic sinus and the lesser curvature of the aorta. We have identified a potential role for increased generation of reactive oxygen species from multiple enzymatic sources in promoting atherosclerosis in this setting.
authors: Division of Cardiovascular and Diabetes Research, Leeds Multidisciplinary Cardiovascular Research Centre, University of Leeds, United Kingdom.
authors: Matthew C
authors: MC
authors: Gage
authors: Nadira Y
authors: NY
authors: Yuldasheva
authors: Hema
authors: H
authors: Viswambharan
authors: Piruthivi
authors: P
authors: Sukumar
authors: Richard M
authors: RM
authors: Cubbon
authors: Stacey
authors: S
authors: Galloway
authors: Helen
authors: H
authors: Imrie
authors: Anna
authors: A
authors: Skromna
authors: Jessica
authors: J
authors: Smith
authors: Christopher L
authors: CL
authors: Jackson
authors: Mark T
authors: MT
authors: Kearney
authors: Stephen B
authors: SB
authors: Wheatcroft
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D001057:Apolipoproteins E / Q000235:genetics; D050197:Atherosclerosis / Q000378:metabolism / Q000503:physiopathology*; D001794:Blood Pressure; D001835:Body Weight; D042783:Endothelial Cells / Q000166:cytology; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology*; D005799:Genes, Dominant; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D017382:Reactive Oxygen Species; D011972:Receptor, Insulin / Q000235:genetics; D012307:Risk Factors
chemical_list: D001057:Apolipoproteins E; D007328:Insulin; D017382:Reactive Oxygen Species; D011972:Receptor, Insulin; D005947:Glucose; D000109:Acetylcholine
keywords: Atherosclerosis; Endothelium; Insulin resistance; Nitric oxide; Oxidative stress