Oxidative Stress Index (OSI) in Children Chronically Exposed to Volatile Organic Compounds (VOC) and their Relation with Genetic Polimorphysms

Abstract

INTRODUCTION The Atoyac River located in the Tlaxcala and Puebla states in Mexico, is receiving domestic and industrial discharges, causing a dramatic deterioration of the environment; various diseases have been reported like leukemia and renal failure on the Atoyac zone habitants that could be related to industrial water pollution. The objective of the research is to study the OSI in children chronically exposed to VOC carried by the river (toluene, xylene, ethyl-benzene and styrene). METHODS 91 children were studied in the area near the river Atoyac and 61 children in a control site (age range: 8-13, no diagnosed chronic diseases). OSI was measured in plasma samples using the total antioxidant capacity (TAC) and the total oxidant status (TOS) based on Erel’s method. Health parameters and anthropometric data were also determined. VOC metabolites were measured in urine. Furthermore, genetic polymorphisms of enzymes involved in VOCs metabolism will be determined: cytochrome P450-2E1*5, glutathione transferases (T1 and M1), and NQO1*2. RESULTS Exposed children presented the TAC response significantly lower than the control group, while TOS did not differ between the two groups, and a significantly higher OSI (5.23 ± 0.357) was found in exposed children than in the group control (2.62 ± 0.187), 95% CI. In the case of VOC metabolites the children presented a concentration above the biological exposure index established by the ACGIH. The polymorphisms that were determined show a high frequency in our population. Conclusions Our first results show that the exposed population exhibits significantly higher levels of a health risk biomarker such as the OSI, which is of concern since our subjects are children. These data will be analyzed in a multivariate model together with VOC metabolite levels, genetic polymorphisms and other variables, in order to obtain a better picture of the factors affecting this important biomarker (OSI), also, in comparison with a control population.