January 25, 2024 — A recent study led by researchers at Washington State University (WSU) has uncovered alarming implications for health issues across generations due to exposure to various toxicants. While previous research has highlighted the impact of single exposures, this study, published in the journal Environmental Epigenetics, delves into the compounding effects of exposure to different toxicants across multiple generations.
The research involved exposing a line of pregnant rats to a common fungicide in the initial generation, followed by exposure to jet fuel in the next generation and, subsequently, exposure to DDT (dichlorodiphenyltrichloroethane) in the subsequent generation. The study extended to a fifth unexposed generation, revealing a significant increase—up to 70%—in the incidence of obesity, kidney diseases, and prostate diseases in those animals.
The lead author of the study, Michael Skinner, a WSU biology professor, emphasized the importance of studying multiple-generation exposures. “We found that if multiple generations get different exposures, then eventually there’s an amplification or compounded effect on some diseases,” said Skinner. The study also explored the impact on epigenetics, molecular processes that influence gene expression independently of DNA.
While certain diseases, particularly those associated with the ovaries and testes, showed an increase in the first generation of progeny, the incidence appeared to plateau with additional generational exposures. The study highlighted a substantial alteration in the animals’ entire epigenetics, suggesting that each new exposure reprogrammed the entire epigenome.
The research, conducted on rats, does not precisely replicate human generational exposure. However, the authors noted that sequential exposure over human generations could involve exposure to toxicants like DDT in the 1950s, followed by plastics in the 1970s, and modern herbicides still in use today.
This study raises concerns about the compounded impact of toxicant exposures across generations and its potential relevance to human health. “Knowing about these possible impacts can help people and doctors address potential diseases before they develop,” Skinner explained.
The study received support from the John Templeton Foundation and the National Institutes of Health. Researchers, including those at Skinner’s lab at WSU, are actively working to identify epigenetic biomarkers for inherited health conditions in humans, such as obesity, autism, and pre-term birth, to better understand and address potential health challenges.