Karlstad [Sweden], February 21 (ANI): Does exposure to chemicals during pregnancy affect a child? Researchers provided evidence that complex mixtures of endocrine disrupting chemicals affect children’s brain development and language learning, by linking human population studies with experiments in cell and animal models.
With their new approach, researchers have shown that up to 54 percent of pregnant women were exposed to experimentally defined levels of anxiety. The study was published in the journal Science.
While the current risk assessment addresses chemicals one at a time, these findings demonstrated the need to take into account mixtures for future risk assessment methods.
There is increasing evidence that environmental chemicals to which we are continuously exposed may have endocrine disrupting properties and thus may be dangerous to human and animal health and development. Every year, a large number of new compounds are released as part of the market approval and production processes for a large number of goods, mainly but not just plastic derivatives, which enter the human body from several sources, including water, food and air.
Although exposure levels to individual chemicals are often below existing limit values, exposure to the same chemicals in complex mixtures can still affect human health. Nevertheless, all existing risk assessments, and thus established limit values, are based on chemicals being examined one at a time.
Thus, there was a great need to test whether an alternative strategy would be possible, where the actual mixtures measured in actual exposures could be tested as such in both epidemiological and experimental environments. The EU-funded EDC-MixRisk project aimed to address this unmet need.
“The unique thing about this comprehensive project is that we have linked population data with experimental studies and then used this information to develop new methods for risk assessment of chemical mixtures,” says Carl-Gustaf Bornehag, professor at Karlstad University, project manager for SELMA- study and responsible for the epidemiological part of EDC-MixRisk.
The study was conducted in three steps: First, a mixture of chemicals in blood and urine was identified in pregnant women in the Swedish pregnancy cohort SELMA, associated with delayed language development in children at 30 months. This critical mixture included a number of phthalates, bisphenol A and perfluorinated chemicals.
Second, experimental studies revealed the molecular targets by which human-relevant levels of this mixture disrupted the regulation of endocrine circuits and of genes involved in autism and intellectual disability.
Third, the results of the experimental studies were used to develop new principles for risk assessment of this mixture.
– It is striking that the findings in the experimental systems well reflected what we found in the epidemiological part, and that the effects could be demonstrated at normal exposure levels for humans, says Joelle Ruegg, professor of environmental toxicology at Uppsala University and deputy coordinator. by EDC-MixRisk.
“Human brain organoids (advanced in vitro cultures that reproduce prominent aspects of human brain development) provided, for the first time, the opportunity to directly investigate the molecular effects of this mixture on human brain tissue at stages that matched those measured during pregnancy. experimental systems and computational methods, we found that the mixture disrupts the regulation of genes linked to autism (one of the hallmarks of which is language disorder), prevents the differentiation of neurons and alters thyroid hormone function in neural tissue, says Giuseppe Testa, chief investigator of EDC-MixRisk responsible for human experimental modeling, professor of molecular biology at the University of Milan, head of the Neurogenomics Research Center at the Human Technopole and group leader at the European Institute of Oncology.
“One of the major hormonal pathways affected was thyroid hormone. Optimal levels of maternal thyroid hormone are needed in early pregnancy for brain growth and development, so it is not surprising that there is a link with language delay as a function of prenatal exposure,” says Barbara. Demeneix, professor of physiology and endocrinology at the Museum of Natural History in Paris and involved in the mechanistic, in vivo, studies.
By linking different scientific methods in this way, the researchers were able to show that 54 percent of the children included in the SELMA study were at risk of delayed language development (at 30 months of age) when they were exposed to a mixture of chemicals at 30 months of age. levels that were above the predicted levels affect neurodevelopment. This risk did not become apparent when the current limit values โโfor individual chemicals were used. (ANI)
Source: sn.dk