The Association of Measures of the Micro- and Macro-Vasculature with Selenium and GPx Activity in a Young Bi-Ethnic Population: The African-PREDICT Study

Abstract

Objective: Selenium plays an important physiological role as component for antioxidant selenoproteins such as glutathione peroxidase (GPx). Since oxidative stress contributes to hypertension development, it is likely that selenium deficiency may contribute to the burden of cardiovascular disease. To better understand the involvement of selenium and GPx in the early development of cardiovascular disease, we investigated in young, healthy black and white African men and women whether measures of the micro- and macrovasculature are related to selenium and GPx activity.

Methods: In young adults (N = 394; aged 20–30 years) we determined serum selenium, GPx activity, microvascular measures (central retinal artery equivalent, central retinal vein equivalent, arteriolar-to-venular ratio [AVR], and estimated glomerular filtration rate [eGFR]), and macrovascular measures (pulse wave velocity, 24-hour pulse pressure [PP] and augmentation index [Aix]).

Results: In multivariable-adjusted regression analyses, there were vasculoprotective associations between serum selenium and a microvascular measure (AVR [β = 0.23; p = 0.036]) in black African women and with a macrovascular measure (24-hour PP [β = −0.15; p = 0.048]) in white African women. In turn, GPx activity also showed a protective association with a microvascular measure (eGFR) in white African men (β = 0.23; p = 0.035), as well as with macrovascular measures (AIx, PP) in the black (β = −0.25; p = 0.027) and white African men (β = −0.22; p = 0.035), and black African women (β = −0.32; p = 0.001).

Conclusions: Collectively the findings suggest a protective role for the micronutrient selenium and GPx on both the micro- and macrovasculature in a young, healthy bi-ethnic population.

Keywords:

• Selenium
• glutathione peroxidase
• microvasculature
• macrovasculature
• young adults

Acknowledgments

The authors are grateful toward all individuals participating voluntarily in the study. The dedication of the support and research staff as well as students at the Hypertension Research and Training Clinic at the North-West University are also duly acknowledged. R. Swart was responsible for the planning, writing, and composition of the manuscript as well as the statistical analyses. C. M. C. Mels, A. E. Schutte, J. M. van Rooyen, and W. Smith gave recommendations for the framework, writing, and composition of the manuscript as well as the methodology. The above-mentioned authors also helped with the collection of the data and supervised the statistical analyses as well as helped with the formulation of the tables.

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Funding

The research funded in this manuscript is part of an ongoing research project financially supported by the South African Medical Research Council (SAMRC) with funds from National Treasury under its Economic Competitiveness and Support Package; the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation (NRF) of South Africa; the Strategic Health Innovation Partnerships Unit of the SAMRC with funds received from the South African National Department of Health, GlaxoSmithKline R&D, the UK Medical Research Council and with funds from the UK Government’s Newton Fund; as well as corporate social investment grants from Pfizer (South Africa), Boehringer-Ingelheim (South Africa), Novartis (South Africa), and the Medi-Clinic Hospital Group (South Africa) and in kind contributions of Roche Diagnostics (South Africa).