Environmental Exposure Associated with Oxidative Stress Biomarkers in Children and Adolescents Residents in Brazilian Western Amazon

Abstract

Oxidative stress is a biological process that occurs in response to an imbalance between prooxidant and antioxidant substances and has been described in the pathophysiology of more than 200 clinical disorders. In this study, we evaluate the relationship between genetic, demographic, social, environmental, and health factors and redox imbalance biomarkers in a group of children and adolescents environmentally exposed to atmospheric pollutants and mercury in the Brazilian Western Amazon. This is a cross-sectional study of the relationship between demographic, genetic, and socioenvironmental factors and serum concentrations of redox imbalance biomarkers (thiol groups, malondialdehyde, and glutathione S-transferase [GST]) in children and adolescents living in the municipality of Porto Velho, Rond&ocirc;nia. The investigated factors were hierarchically organized into groups of variables and their relationship with redox imbalance biomarkers was estimated by a multiple linear regression model. Children and adolescents with asthma, with C-reactive protein values, with the polymorphic variant GSTP1, and exposed to indoor air pollution presented lower thiol serum concentrations when compared to those categorized in their respective reference groups. GST activity and malondialdehyde serum concentrations were positively related to weekly fish consumption and exposure to PM2.5. This study showed that enzymatic GST activity and malondialdehyde serum concentrations are positively associated with environmental factors, especially air pollution (β = 8.64 U/L for GST and β = 0.244 &micro;mol/L for MDA in high exposure group; p-value < 0.01); while serum thiol concentrations presented an inversely proportional relationship with markers of general health status, such asthma (median: 0.45 mmol/L vs. 0.48 mmol/L; p-value < 0.05), acute inflammation (β = -0.25 mmol/L; p-value < 0.01), and positively with genetic factor (β = 0.12 mmol/L for Val/Val; p-value < 0.05).