Primate study offers more bad news about BPA

"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," says Frederick vom Saal. (Credit: iStockphoto)

Even low exposure to Bisphenol A (BPA)—a chemical found in everything from paper receipts to cans of soup—appears to cause fetal abnormalities in primates.

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“BPA is an endocrine disrupting chemical that has been demonstrated to alter signaling mechanisms involving estrogen, androgen, and thyroid hormones,” says Frederick vom Saal, a professor of biological sciences at the University of Missouri. “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.”

Although BPA is considered a toxic chemical in other countries such as Canada, the United States has been slow to address the issue, says vom Saal.

Until now, most studies involving BPA have been conducted on laboratory mice and rats, leading US regulatory agencies to call for studies in primates. The study by vom Saal and colleagues looked at the chemical’s blood levels in pregnant female rhesus monkeys and their fetuses, which are considered to be very similar to human fetuses.

Humans exposed every day

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 says. “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 National Institute of Environmental Health Sciences provided partial funding for the study, which was published in the journal Reproductive Toxicology in collaboration with researchers from the University of California, Davis, the Univesite de Toulouse, and Washington State University.

Source: University of Missouri