U.S. regulators have been slow to restrict the use of Bisphenol A (BPA), a chemical widely used in consumer products including food packaging, store receipts and dental composites.
Although many countries, including Canada, consider BPA a toxin, the U.S. has held out for more studies of its effects on primates -- the category of animal that includes humans -- instead of tests on mice and rats.
Now, researchers at the University of Missouri have obliged, with tests that determined that daily exposure to very low concentrations of BPA by pregnant females can indeed cause fetal abnormalities in primates, just as they have been shown to do in rodents.
“BPA is an endocrine disrupting chemical that has been demonstrated to alter signaling mechanisms involving estrogen, androgen and thyroid hormones,” said Frederick vom Saal, Curators Professor of Biological Sciences in the College of Arts and Science at MU. “Previous studies in rodents have demonstrated that maternal exposure to very low doses of BPA can significantly alter fetal development, resulting in a variety of adverse outcomes in the fetus. Our study is one of the first to show this also happens in primates.”
With funding provided by the National Institute of Environmental Health Sciences (NIEHS), a research institute of the National Institutes of Health, vom Saal and his colleagues studied the chemical’s blood levels in pregnant female rhesus monkeys and their fetuses, which are considered to be very similar to human fetuses.
"Significant adverse effects"
After collecting tissue samples, other researchers analyzed the tissues to determine if BPA exposure was harmful to fetal development. Researchers found evidence of significant adverse effects in mammary glands, ovaries, brain, uterus, lung and heart tissues in BPA exposed fetus when compared to fetuses not exposed to BPA.
The abnormalities were caused by levels of BPA in the monkey fetuses that were very similar to levels reported in previous studies of BPA in human fetuses.
“The very low-level exposure to BPA we delivered once a day to the rhesus monkeys is far less than the BPA levels humans are exposed to each day, which reflects multiple exposures,” vom Saal said. “Our findings suggest that traditional toxicological studies likely underestimate actual human exposure and show, unequivocally, that biologically active BPA passes from the mother to the fetus. Additionally, our latest study shows that BPA causes damage to developing systems of monkey fetuses, and this is of great concern for human fetuses.”
The study was published in Reproductive Toxicology.