title: SIRT1, heme oxygenase-1 and NO-mediated vasodilation in a human model of endogenous angiotensin II type 1 receptor antagonism: implications for hypertension.
abstract: Reduced NO availability is associated with endothelial dysfunction, hypertension, insulin resistance and cardiovascular remodeling. SIRT1 upregulates eNOS activity and inhibits endothelial cell senescence, and reduced SIRT1 is related to oxidative stress and reduced NO-dependent dilation. Bartter's/Gitelman's syndromes (BS/GS) are rare diseases that feature a picture opposite to that of hypertension in that they present with normo/hypotension, reduced oxidative stress and a lack of cardiovascular remodeling, notwithstanding high levels of angiotensin II and other vasopressors, upregulation of NO system, and increased NO-dependent vasodilation (FMD), as well as increase in both endothelial progenitor cells and insulin sensitivity. To our knowledge, in BS/GS patients SIRT1 has never been evaluated. BS/GS patients' mononuclear cell SIRT1 (western blot), FMD (B-mode scan of the right brachial artery) and heme oxygenase (HO)-1 (sandwich immunoassay), a potent antioxidant protein, were compared with the levels in untreated stage 1 essential hypertensive patients (HPs) and in healthy subjects (C). SIRT1 (1.86 ± 0.29 vs. 1.18 ± 0.18 (HP) vs. 1.45 ± 0.18 (C) densitometric units, P<0.0001) and HO-1 protein (9.44 ± 3.09 vs. 3.70 ± 1.19 (HP) vs. 5.49 ± 1.04 (C) ng ml⁻¹, P<0.0001) levels were higher in BS/GS patients than in the other groups. FMD was also higher in BS/GS patients: 10.52 ± 2.22% vs. 5.99 ± 1 .68% (HP) vs. 7.99 ± 1.13% (C) (ANOVA: P<0.0001). A strong and significant correlation between SIRT1 and FMD was found only in BS/GS patients (r(2)=0.63, P=0.0026). Increased SIRT1 and its direct relationship with increased FMD in BS/GS patients, while strengthening the relationship among SIRT1, NO and vascular function in humans, point toward a role for reduced SIRT1 in the endothelial dysfunction of hypertension.
authors.affiliation: Department of Nutrition, University of California, Davis, CA, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Davis
authors.forename: Elisa
authors.initials: E
authors.lastname: Pagnin
authors.forename: Lucia
authors.initials: L
authors.lastname: Dal Maso
authors.forename: Paola
authors.initials: P
authors.lastname: Caielli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maiolino
authors.forename: Maria
authors.initials: M
authors.lastname: Fusaro
authors.forename: Gian
authors.initials: G
authors.lastname: Paolo Rossi
authors.forename: Lorenzo A
authors.initials: LA
authors.lastname: Calò
mesh_terms: D000328:Adult; D001477:Bartter Syndrome / Q000378:metabolism / Q000503:physiopathology; D001916:Brachial Artery / Q000502:physiology*; D002319:Cardiovascular System / Q000378:metabolism / Q000503:physiopathology; D016022:Case-Control Studies; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D053579:Gitelman Syndrome / Q000378:metabolism / Q000503:physiopathology; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D056564:Sirtuin 1 / Q000378:metabolism*; D014664:Vasodilation / Q000502:physiology*
chemical_list: D044140:Receptor, Angiotensin, Type 1; D009569:Nitric Oxide; D051547:Heme Oxygenase-1; C447939:SIRT1 protein, human; D056564:Sirtuin 1