DDT exposure found to alter sperm epigenome in humans

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In a study of possible reproductive signals and health complications in humans, now and for future generations, researchers from McGill University, University of Pretoria, Université Laval, Aarhus University and the University of Copenhagen concluded that fathers exposed to environmental toxins, particularly DDT, are more likely to pass on their offspring. May produce sperm with health consequences.

The decade-long research project examined the effects of DDT on the sperm epigenome of Vavenda and Greenlandic Inuit men in South Africa, some of whom live in northern Canada.

The research is published in the journal Environmental Health Perspectives, demonstrating a link between long-term exposure to DDT and changes in the sperm epigenome. These changes, particularly in genes essential for fertility, fetal development, neurodevelopment and hormone regulation, correspond to increased rates of birth defects and diseases, including neurodevelopmental and metabolic disorders.

“We’ve identified regions of the sperm epigenome that are associated with serum levels of DDE (chemicals that are produced when DDT is broken down) and this association follows a dose-response trend. I think it’s quite interesting, the more DDE you have in sperm, the more chromatin or DNA methylation. The higher the error, the more exposure there is,” said Ariane Lismer, PhD, the study’s lead author, who completed the work while doing her PhD in McGill’s Department of Pharmacology and Therapeutics.

“We show that the response of the sperm epigenome to toxin exposure may be associated with later-generation disease,” said Sarah Kimmins, PhD, who led the research as McGill’s professor of pharmacology and therapeutics and is currently a professor in the department of pathology. and cell biology at the Université de Montréal. “This is an important new step for the field because while there are many animal studies showing toxic effects on the sperm epigenome, human studies have not widely demonstrated this.”

Malaria, climate change, and the ‘locust effect’

Despite a worldwide ban on DDT to protect people and the environment from its effects, the South African government has granted special permission to use it as an insecticide to control malaria. In some regions, the interiors of houses are covered with poison. The research findings emphasize the urgency of finding alternative ways to control malaria and other vector-borne diseases.

The reality is that people, especially young children and pregnant women, are still dying from malaria. We cannot refuse people in malaria-endemic areas to spray their homes, as this will increase their risk of contracting malaria.”


Tian de Jager, PhD, Dean of the Faculty of Health Sciences and Professor of Environmental Health in the School of Health Systems and Public Health, University of Pretoria

What’s more, climate change is known to increase the number of people and animals exposed to DDT. DDT can evaporate with warm air and return to Earth with rain and snow in colder regions, known as the ‘grasshopper effect’, where it persists in the Arctic food chain.

Rethinking the role of fathers in child development

The findings also highlight the importance of considering fathers in discussions about child health and development. Although it is generally understood that women should avoid exposure to environmental pollutants during pregnancy, less attention has been paid to how toxins affect fathers.

“We think all fathers have to do is fertilize. But actually, we forget that half of that genome and epigenome comes from fathers, and half comes from mothers. What that epigenome does in fetal development is critical to normal development,” said study co. -The author, Janice Bailey, PhD, is a former professor of zoology at Université Laval and now scientific director of the Fonds de Recherche du Québec en Nature et Technologies (FRQNT).

Although the study focused on DDT exposure, the researchers say it’s not a leap that exposure to more common household endocrine disruptors, such as those found in cosmetics and personal care items, could act similarly.

Source:

Journal Reference:

Lijmar, A., etc (2024). Association between long-term DDT or DDE exposure and an altered sperm epigenome – a cross-sectional study in Greenlandic Inuit and South African Vavenda men. Environmental Health Perspectives. doi.org/10.1289/ehp12013.



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