Title : Health risks associated with exposure to organic sunscreens during pregnancy
Abstract:
Pregnant women are exposed to a variety of environmental pollutants – pesticides, drugs, substances of abuse or cosmetic raw materials that enter the body of a mother-to-be by a variety of routes - oral (with contaminated food or water), through skin or mucous membranes or by inhalation. The placenta is an interface between the maternal and fetal compartments; molecules are transported across the placenta mainly via passive diffusion, but other mechanisms (involving facilitated diffusion, placental transporters, phagocitosis or pinocitosis) are also possible.
Organic sunscreens are expected to act on the surface of the skin or hair to protect them against harmful effects of UV radiation; some sunscreens are also used to prevent photo-induced degradation of products – fabrics, cosmetic preparations etc. Unfortunately, many compounds from this group meet the conditions of drug-likeness and are known to be absorbed through skin, from the gastro-intestinal or pulmonary tract. Some organic sunscreens are found in mother’s milk, umbilical cord blood or placental tissues. Organic sunscreens are not neutral to human and animal health; they are known endocrine disruptors and, generally speaking, can influence the development of offspring (especially male fetuses) or are suspected neurotoxins.
Earlier reports exist that some organic sunscreens from the chemical family of benzophenones cross the human placenta. In this research it was shown using Discriminant Analysis (DA) and Artificial Neural Networks (ANN) classification models (based on a training set of 40 compounds and a test set of 14 compounds) that the majority of organic sunscreens authorized for use in the EC (and in many states worldwide), including those from chemical families other than benzophenone derivatives, are likely to cross the placenta easily. The passage of these compounds across the placenta is facilitated mainly by passive diffusion and their ability to enter the fetal blood circulation is strongly related to their drug-likeness according to Lipinski’s Rule of Five. Apart from trans-placental passage, many sunscreens are likely to penetrate the fetal brain. They are also (as proved by molecular docking calculations) likely to bind to enzymes found in placenta, whose main task is to protect the fetus from harmful xenobiotics, e.g. glutathione s-transferase or N-acetyltransferase 2. The binding affinities of the sunscreens for studied proteins were analyzed to give an idea of the potential of these chemicals to block the enzyme targets. Binding sites of both proteins and protein-ligand interaction types were identified.
Audience Take Away Notes:
- What are the possible impacts of organic sunscreens on a human fetus
- Can organic sunscreens cross the human placenta and what happens to them after they enter the fetal circulation
- Are organic sunscreens likely to interfere with enzymes in the human placenta, e.g. glutathione s-transferase or N-acetyltransferase 2
