The impact of environmental pollutants on the reproduction of future generations
Currently, we are facing a major environmental, societal and health issue due to the increasing presence of environmental pollutants from the agri-food (e.g. pesticides and fungicides), petrochemical (e.g. bisphenols and phthalates), pharmaceutical (paracetamol) and cosmetic (sunscreens) industries. We are all exposed to dozens of substances on a daily basis. Among these pollutants, several hundred are identified as endocrine disruptors (EDs). These substances are capable of altering hormonal homeostasis and increasing the risk of numerous disorders. They are the main research topic of Anne-Simone Parent's team at GIGA-Neuroscience (Neuroendocrinology Laboratory -ULiège). The developing organism and in particular the brain is especially sensitive to EPs. Exposure to EPs during development can lead to alterations in the neural circuits that control sexual development and reproductive function in adulthood. Moreover, recent data suggest that these alterations may persist over several generations.
In Anne-Simone Parent's laboratory, a recent study published in Environmental Health Perspectives examined the effects of a mixture of 13 POPs to which we are commonly exposed at low doses on sexual development and maternal behavior over three generations of female rats. The mixture containing plastics, pesticides, fungicides, sunscreens and paracetamol was administered before gestation until the end of lactation. The study shows that developmental exposure to a mixture of PEs leads to altered puberty, ovulatory cycle and ovarian folliculogenesis two and three generations after exposure. As Anne-Simone Parent points out, "these results call into question the current methods of evaluating the danger of endocrine disruptors since their effects are not seen directly after exposure during pregnancy, but in the second and third generations". These effects are therefore particularly worrying since the third generation has never been directly exposed to EPs. The study shows that the transmission of these effects on reproduction could be explained by alterations of germ cells which would then lead to an epigenetic reprogramming of the hypothalamic control of reproduction. In addition, the team identified alterations in maternal behavior caused by abnormalities in hypothalamic dopaminergic signaling. This altered maternal behavior is transmitted from generation to generation through learning.
Overall, this study highlights the brain mechanisms explaining the effects of a mixture of EPs on reproduction across several generations of animals. These results raise concerns about the potential consequences of EPs on our future generations.
David López-Rodríguez, Carlos Francisco Aylwin, Virginia Delli, Elena Sevrin, Marzia Campanile, Marion Martin, Delphine Franssen, Arlette Gérard, Silvia Blacher, Ezio Tirelli, Agnès Noël, Alejandro Lomniczi, Anne-Simone Parent
Environ Health Perspect. 2021 Aug;129(8):87003.