Antioxidant enzyme and DNA base repair genetic risk scores’ associations with systemic oxidative stress biomarker in pooled cross-sectional studies

• Authors: Ziling Mao, Emory University; Abigail LH Gray, Emory University; Bharat Thyagarajan, University of Minnesota Twin Cities; Roberd Bostick, Emory University
• Journal Title: Frontiers in Aging
• Volume: Volume 4
• Publisher: Frontiers | 2023-01-01, Pages 1000166-1000166
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3389/fragi.2023.1000166
• Subjects: Health Sciences, Epidemiology
• Keywords: DNA base excision repair; F2-isoprostanes; antioxidant enzymes; cross-sectional studies; genetic risk score; oxidative balance; oxidative balance score; oxidative stress

Abstract

Background: Oxidative stress is hypothesized to contribute to the pathogenesis of several chronic diseases. Numerous dietary and lifestyle factors are associated with oxidative stress; however, little is known about associations of genetic factors, individually or jointly with dietary and lifestyle factors, with oxidative stress in humans. Methods: We genotyped 22 haplotype-tagging single nucleotide polymorphisms (SNPs) in 3 antioxidant enzyme (AE) genes and 79 SNPs in 14 DNA base excision repair (BER) genes to develop oxidative stress-specific AE and BER genetic risk scores (GRS) in two pooled cross-sectional studies (n = 245) of 30–74-year-old, White, cancer- and inflammatory bowel disease-free adults. Of the genotypes, based on their associations with a systemic oxidative stress biomarker, plasma F2-isoprostanes (FiP) concentrations, we selected 4 GSTP1 SNPs for an AE GRS, and 12 SNPs of 5 genes (XRCC1, TDG, PNKP, MUTYH, and FEN1) for a BER GRS. We also calculated a previously-reported, validated, questionnaire-based, oxidative stress biomarker-weighted oxidative balance score (OBS) comprising 17 anti- and pro-oxidant dietary and lifestyle exposures, with higher scores representing a higher predominance of antioxidant exposures. We used general linear regression to assess adjusted mean FiP concentrations across GRS and OBS tertiles, separately and jointly. Results: The adjusted mean FiP concentrations among those in the highest relative to the lowest oxidative stress-specific AE and BER GRS tertiles were, proportionately, 11.8% (p = 0.12) and 21.2% (p = 0.002) higher, respectively. In the joint AE/BER GRS analysis, the highest estimated mean FiP concentration was among those with jointly high AE/BER GRS. Mean FiP concentrations across OBS tertiles were similar across AE and BER GRS strata. Conclusion: Our pilot study findings suggest that DNA BER, and possibly AE, genotypes collectively may be associated with systemic oxidative stress in humans, and support further research in larger, general populations.