Xuefeng Ren, M.D., Ph.D.
State University Of New York At Buffalo
Arsenic exposure across generations was associated with common DNA methylation changes despite different exposure timing, according to an NIEHS-funded study. The new analysis also suggested that some of the DNA methylation changes altered by arsenic exposure might have the potential to be inherited.
The study was based in Hetao Plain, Inner Mongolia, China, where deep wells containing high levels of arsenic in water sources were switched to reduce arsenic exposure in the early 1990s. Researchers compared households exposed to arsenic before the wells were switched with unexposed households. The study included three generations — grandparents, parents, and grandchildren — living in the same household. The grandparents were exposed to arsenic in adulthood, and the parents were exposed in the womb or early in life.
The researchers isolated DNA from blood and examined DNA methylation patterns across the genome. They identified a number of DNA methylation differences between exposed and unexposed people and showed that arsenic exposure might leave detectable DNA methylation changes, even when exposure occurred decades earlier. Members of exposed families shared common genome regions where DNA was differentially methylated, despite different exposure timing. Because the changes were also seen in the grandchildren, the researchers suggested that these methylation patterns might be inherited.
According to the authors, the common DNA methylation regions associated with an increased risk for disease development might be able to serve as biomarkers for identifying individuals at risk for arsenic-induced skin lesions and cancers, regardless of when arsenic exposure occurred.
Citation: Guo X, Chen X, Wang J, Liu Z, Gaile D, Wu H, Yu G, Mao G, Yang Z, Di Z, Guo X, Cao L, Chang P, Kang B, Chen J, Gao W, Ren X. 2018. Multi-generational impacts of arsenic exposure on genome-wide DNA methylation and the implications for arsenic-induced skin lesions. Environ Int 119:250-263.