Oxidative stress [increased bioavailability of reactive oxygen species (ROS)] plays a role in the endothelial dysfunction and vascular inflammation, which underlie vascular damage in diabetes. Statins are cholesterol-lowering drugs that are vasoprotective in diabetes through unknown mechanisms. We tested the hypothesis that atorvastatin decreases NADPH oxidase (Nox)-derived ROS generation and associated vascular injury in diabetes. Leprdb/Leprdb (db/db) mice, a model of Type 2 diabetes and control Leprdb/Lepr+ (db/+) mice were administered atorvastatin (10 mg/kg per day, 2 weeks). Atorvastatin improved glucose tolerance in db/db mice. Systemic and vascular oxidative stress in db/db mice, characterized by increased plasma TBARS (thiobarbituric acid-reactive substances) levels and exaggerated vascular Nox-derived ROS generation respectively, were inhibited by atorvastatin. Cytosol-to-membrane translocation of the Nox regulatory subunit p47phox and the small GTPase Rac1/2 was increased in vessels from db/db mice compared with db/+ mice, an effect blunted by atorvastatin. The increase in vascular Nox1/2/4 expression and increased phosphorylation of redox-sensitive mitogen-activated protein kinases (MAPKs) was abrogated by atorvastatin in db/db mice. Pro-inflammatory signalling (decreased IκB-α and increased NF-κB p50 expression, increased NF-κB p65 phosphorylation) and associated vascular inflammation [vascular cell adhesion molecule-1 (VCAM-1) expression and vascular monocyte adhesion], which were increased in aortas of db/db mice, were blunted by atorvastatin. Impaired acetylcholine (Ach)- and insulin (INS)-induced vasorelaxation in db/db mice was normalized by atorvastatin. Our results demonstrate that, in diabetic mice, atorvastatin decreases vascular oxidative stress and inflammation and ameliorates vascular injury through processes involving decreased activation of Rac1/2 and Nox. These findings elucidate redox-sensitive and Rac1/2-dependent mechanisms whereby statins protect against vascular injury in diabetes.
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Research Article|
December 09 2014
Vascular injury in diabetic db/db mice is ameliorated by atorvastatin: role of Rac1/2-sensitive Nox-dependent pathways
Thiago Bruder-Nascimento;
Thiago Bruder-Nascimento
*Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
†Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
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Glaucia E. Callera;
Glaucia E. Callera
†Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
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Augusto C. Montezano;
Augusto C. Montezano
‡Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, U.K.
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Ying He;
Ying He
†Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
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Tayze T. Antunes;
Tayze T. Antunes
†Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
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Aurelie Nguyen Dinh Cat;
Aurelie Nguyen Dinh Cat
‡Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, U.K.
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Rita C. Tostes;
Rita C. Tostes
*Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
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Rhian M. Touyz
†Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
‡Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, U.K.
Correspondence: Professor Rhian M. Touyz (email [email protected]).
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Publisher: Portland Press Ltd
Received:
July 29 2014
Revision Received:
September 30 2014
Accepted:
October 31 2014
Accepted Manuscript online:
October 31 2014
Online ISSN: 1470-8736
Print ISSN: 0143-5221
© The Authors Journal compilation © 2015 Biochemical Society
2015
Clin Sci (Lond) (2015) 128 (7): 411–423.
Article history
Received:
July 29 2014
Revision Received:
September 30 2014
Accepted:
October 31 2014
Accepted Manuscript online:
October 31 2014
Citation
Thiago Bruder-Nascimento, Glaucia E. Callera, Augusto C. Montezano, Ying He, Tayze T. Antunes, Aurelie Nguyen Dinh Cat, Rita C. Tostes, Rhian M. Touyz; Vascular injury in diabetic db/db mice is ameliorated by atorvastatin: role of Rac1/2-sensitive Nox-dependent pathways. Clin Sci (Lond) 1 April 2015; 128 (7): 411–423. doi: https://doi.org/10.1042/CS20140456
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