Arsenic exposure, telomere length, and expression of telomere-related genes among Bangladeshi individuals.

Background: Inorganic arsenic is a carcinogen whose mode of action may involve telomere dysfunction. Recent epidemiological studies suggest that chronic arsenic exposure is associated with longer telomeres and altered expression of telomere-related genes in peripheral blood. In this study, we evaluated the association of urinary arsenic concentration with expression of telomere-related genes and telomere length in Bangladeshi individuals with a wide range of arsenic exposure through naturally contaminated drinking water.
Methods: We used linear regression models to estimate associations between urinary arsenic and array-based expression measures for 69 telomere related genes using mononuclear cell RNA samples from 1799 individuals. Association between arsenic exposure and a qPCR-based telomere length measure was assessed among 167 individuals.
Results: Urinary arsenic was positively associated with expression of WRN, and negatively associated with TERF2, DKC1, TERF2IP and OBFC1 (all P<0.00035, Bonferroni-corrected threshold). We detected interaction between urinary arsenic and arsenic metabolism efficiency in relation to expression of WRN (P for interaction =0.00008). In addition, we observed that very high arsenic exposure was associated with longer telomeres compared to very low exposure (P=0.02).
Discussion: Our findings suggest that arsenic's carcinogenic mode of action may involve alteration of telomere maintenance and/or telomere damage. This study extends our knowledge regarding the effect of arsenic on telomere length and expression of telomere-related genes.
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