A new approach to study stochastic epigenetic mutations in sperm methylome of Vietnam war veterans directly exposed to Agent Orange.

Abstract

Among the various environmental pollutants, dioxin, a highly toxic and widely used compound, is associated with numerous adverse health effects, including a potentially toxic multigenerational effect. Understanding the mechanisms by which dioxin exposure can affect sperm epigenetics is critical to comprehending the potential consequences for offspring health and development. This study investigates the possible association between weighted epimutations, hypothesized as markers of epigenetic drift, and dioxin exposure in sperm tissues. We used a public online methylation dataset consisting of 37 participants: 26 Vietnam veterans exposed to Agent Orange, an herbicide contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and 11 individuals not directly exposed to TCDD but whose serum dioxin levels are equivalent to the background. In our study, conducted at the gene level, 437 epimutated genes were identified as significantly associated with each single-digit increase in serum dioxin levels. We found no significant association between the rise in total epimutation load and serum dioxin levels. The pathway analysis performed on the genes reveals biological processes mainly related to changes in embryonic morphology, development, and reproduction. Results from our current study suggest the importance of further investigations on the consequences of dioxin exposure in humans with specific reference to germinal tissue and related heredity.