title: The relationship of nitric oxide synthesis capacity, oxidative stress, and albumin-to-creatinine ratio in black and white men: the SABPA study.
abstract: Inadequate substrate availability and increased nitric oxide synthase inhibitor levels attenuate nitric oxide (NO) synthesis, whereas increased vascular oxidative stress may lead to inactivation of NO. We compared markers of NO synthesis capacity and oxidative stress in a bi-ethnic male population. Inter-relationships of ambulatory blood pressure and urinary albumin-to-creatinine ratio with NO synthesis capacity and oxidative stress markers were investigated. NO synthesis capacity markers (L-arginine, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA)) and oxidative stress markers (serum peroxides, total glutathione, glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase) were measured. Black men displayed higher blood pressure and albumin-to-creatinine ratio (all p < 0.001), while NO synthesis capacity was more favorable (higher L-arginine and lower ADMA (p ≤ 0.003)). Antioxidant enzyme activities were similar except for the redox status markers (GR activity and GR/GPx ratio), which were upregulated in black men (p < 0.001). In black men, ADMA was inversely related to GPx activity (R (2) = 0.15; β = -0.20; p = 0.050) and GPx/SOD ratio (R (2) = 0.24; β = -0.37; p < 0.001), but none of these markers related to blood pressure or albumin-to-creatinine ratio. In white men, albumin-to-creatinine ratio was positively associated with ADMA (R (2) = 0.18; β = 0.39; p < 0.001) while ADMA was inversely related to GR activity (R (2) = 0.26; β = -0.29; p = 0.002) and GR/GPx ratio (R (2) = 0.25; β = -0.28; p = 0.003). Black men with elevated blood pressure and albumin-to-creatinine ratio displayed a favorable NO synthesis capacity. This may be counteracted by increased inactivation of NO, although it was not linked to vascular or renal phenotypes. In white men, reduced NO synthesis capacity may lower NO bio-availability, thereby influencing the albumin-to-creatinine ratio.
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa. Carina.Mels@nwu.ac.za.
authors.forename: Catharina M C
authors.initials: CM
authors.lastname: Mels
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.|MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
authors.forename: Hugo W
authors.initials: HW
authors.lastname: Huisman
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
authors.forename: Wayne
authors.initials: W
authors.lastname: Smith
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.|School of Public Health, Epidemiology and Biostatistics, Imperial College London, London, UK.
authors.forename: Rudolph
authors.initials: R
authors.lastname: Schutte
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Edzard
authors.initials: E
authors.lastname: Schwedhelm
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.|Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Atzler
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Rainer H
authors.initials: RH
authors.lastname: Böger
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Ware
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.|MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
mesh_terms: D000328:Adult; D001741:Black or African American; D000375:Aging / Q000208:ethnology / Q000502:physiology; D000418:Albumins / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D006801:Humans; D006973:Hypertension / Q000208:ethnology* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000096:biosynthesis*; D018384:Oxidative Stress; D013564:Sympathetic Nervous System / Q000378:metabolism / Q000503:physiopathology; D014481:United States / Q000453:epidemiology; D044465:White People
chemical_list: D000418:Albumins; D015415:Biomarkers; D009569:Nitric Oxide; D003404:Creatinine
keywords: African; Asymmetric dimethylarginine; Glutathione peroxidase; Glutathione reductase; Nitric oxide; Race; Urinary albumin-to-creatinine ratio; Vasodilation