DNA methylation changes in Mexican children exposed to arsenic from two historic mining areas in San Luis potosí

Abstract

Arsenic is a carcinogen and epimutagen that threatens the health of exposed populations worldwide. In this study, we examined the methylation status of Alu and long interspersed nucleotide elements (LINE-1) and their association with levels of urinary arsenic in 84 Mexican children between 6 and 12 years old from two historic mining areas in the State of San Luis Potosí, Mexico. Urinary arsenic levels were determined by atomic absorption spectrophotometry and DNA methylation analysis was performed in peripheral blood leukocytes by bisulfite-pyrosequencing. The geometric mean of urinary arsenic was 26.44 µg/g Cr (range 1.93-139.35). No significant differences in urinary arsenic or methylation patterns due to gender were observed. A positive correlation was found between urinary arsenic and the mean percentage of methylated cytosines in Alu sequences (Spearman correlation coefficient r = 0.532, P < 0.001), and a trend of LINE-1 hypomethylation was also observed (Spearman correlation coefficient r = -0.232, P = 0.038) after adjustment for sex and age. A linear regression model showed an association with log-normalized urinary arsenic for Alu (β = 1.05, 95% CI: 0.67; 1.43, P < 0.001) and LINE-1 (β = -0.703, 95% CI: -1.36; -0.38, P = 0.038). Despite the low-level arsenic exposure, a subtle epigenetic imbalance measured as DNA methylation was detected in the leukocytes of Mexican children living in two historic mining areas. Environ. Mol. Mutagen. 57:717-723, 2016. © 2016 Wiley Periodicals, Inc.

Potential Co-exposure to Arsenic and Fluoride and Biomonitoring Equivalents for Mexican Children

“…Similar to adults, children showed genetic damage associated with arsenic exposure [333435]. Epigenetic changes were observed in cord-blood cells [32363738] and in leukocytes from child populations exposed to arsenic in drinking water [39] or in historic mining areas [40].…”

50‐Hz MF does not affect global DNA methylation of SH‐SY5Y cells treated with the neurotoxin MPP+

“…Limitations related to this analysis include the use of these sequences as a surrogate of global DNA methylation and the small number of analyzed CpG, as compared to other techniques, such as MassARRAY or Epyter analysis. Nevertheless, they are widely used in the literature and have been validated as reliable biomarkers of genomic DNA methylation in response to environmental stress, including radiation [Bollati et al, ; Baccarelli et al, ; Aypar et al, ; Consales et al, ; Leter et al, ; Alegría‐Torres et al, ; Koturbash, ].…”

Health effects of arsenic exposure in Latin America: An overview of the past eight years of research

“…In contrast, for 1 variant (rs17881215), associations were significantly stronger at exposures >50 μg/L (Xu et al, 2016). Methylation status of Alu and long interspersed nucleotide elements (LINE-1) were also assessed in Mexican children who were living in historic mining areas (Alegria-Torres et al, 2016). Associations of log-normalized UAs with Alu (β = 1.05, 95% CI: 0.67, 1.43) as well as with LINE-1 (β=−0.703, 95% CI: −1.36, −0.38) were reported providing evidence of subtle epigenetic imbalance measured as DNA methylation although no significant difference in As methylation pattern by sex was observed (Alegria-Torres et al, 2016).…”