Three-year change in oxidative stress markers is linked to target organ damage in black and white men: the SABPA study

Abstract

Oxidative stress is implicated in hypertension, carotid wall thickening, and renal dysfunction. Oxidative stress is linked to cardiovascular pathology in the black South African individuals who have a high prevalence of hypertension and early vascular aging. However, there are limited data relating changes in oxidative stress with vascular and renal deterioration over time. We aimed to investigate whether changes in oxidative stress over 3 years are associated with target organ damage in black (N = 89) and white (N = 91) men. Carotid intima-media thickness was measured using the SonoSite Micromaxx ultrasound system, and cross-sectional wall area (CSWA) was calculated. The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease formula. The percentage change (%∆) in oxidative stress markers was calculated and included reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR). Over 3 years, black men exhibited decreased ROS, SOD, and GR, while white men revealed decreased SOD and GPx. Black men displayed positive associations of CSWA with %∆ ROS (β = 0.28; p = 0.017) and %∆ SOD (β = 0.24; p = 0.047). White men displayed a negative association of CSWA with %∆ SOD (β = −0.22; p = 0.042) and positive associations of eGFR with %∆ GPx (β = 0.33; p = 0.001) and %∆ GR (β = 0.39; p < 0.001). In white men, the association of CSWA with decreased SOD activity suggests oxidative-stress-related carotid remodeling, while associations of eGFR with the glutathione system suggests a postponement of microvascular deterioration. In black men, associations of oxidative stress markers with CSWA suggest that a sufficiently functioning antioxidant system may delay target organ damage