8-Oxo-7, 8-dihydro-2'-deoxyguanosine, reactive oxygen species and ambulatory blood pressure in African and Caucasian men: The SABPA study. (November 2014)

• Record Type: Journal Article
• Authors: Mels, C. M.C.; Schutte, A. E.; Schutte, R.; Pretorius, P. J.; Smith, W.; Huisman, H. W.; van der Westhuizen, F. H.; Fourie, C. M. T.; van Rooyen, J. M.; Kruger, R.; Louw, R.; Malan, N. T.; Malan, L.
• Is Part Of: Free radical research. Volume 48:Number 11(2014:Nov.)
• Page Start: 1291
• Page End: 1299
• Publication Date: 2014-11
• Subjects: Free radicals (Chemistry) -- Periodicals; Antioxidants -- Periodicals; Vitamin C -- Periodicals; Vitamin E -- Periodicals; 541.224
• DOI: 10.3109/10715762.2014.951840
• Languages: English
• ISSNs: 1071-5762

Abstract

<abstract> <title>Abstract</title> <p>Various studies indicate a relationship between increased oxidative stress and hypertension, resulting in increased DNA damage and consequent excretion of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG). The aim of this study was to compare urinary 8-oxodG levels in African and Caucasian men and to investigate the association between ambulatory blood pressure (BP) and pulse pressure (PP) with 8-oxodG in these groups.</p> <p>We included 98 African and 92 Caucasian men in the study and determined their ambulatory BP and PP. Biochemical analyses included, urinary 8-oxodG, reactive oxygen species (ROS) (measured as serum peroxides), ferric reducing antioxidant power (FRAP), total glutathione (GSH), glutathione peroxidase (GPx) and glutathione reductase (GR) activity.</p> <p>The African men had significantly higher systolic (SBP) and diastolic blood pressure (DBP) (both <italic>p</italic> < 0.001). Assessment of the oxidative stress markers indicated significantly lower 8-oxodG levels (<italic>p</italic> < 0.001) in the African group. The African men also had significantly higher ROS (<italic>p</italic> = 0.002) with concomitant lower FRAP (<italic>p</italic> < 0.001), while their GSH levels (<italic>p</italic> = 0.013) and GR activity (<italic>p</italic> < 0.001) were significantly higher. Single and partial regression analyses indicated a negative association between urinary 8-oxodG levels with SBP, DBP and PP only in African men. These associations were confirmed in multiple regression analyses (SBP: R<sup>2</sup> = 0.41; β = −0.25; <italic>p</italic> = 0.002, DBP: R<sup>2</sup> = 0.30; β = −0.21; <italic>p</italic> = 0.022, PP: R<sup>2</sup> = 0.30; β = −0.19; <italic>p</italic> = 0.03).</p> <p>Our results revealed significantly lower urinary 8-oxodG in African men, accompanied by a negative association with BP and PP. We propose that this may indicate a dose-response relationship in which increased oxidative stress may play a central role in the up-regulation of antioxidant defence and DNA repair mechanisms.</p> </abstract>