MU professor, Cheryl Rosenfeld, has researched the chemical bisphenol A for over a decade. Her work, recently published in the journal, Epigenetics, disproves a statement issued by the U.S. Food and Drug Administration earlier this year.
Bisphenol A, also known as BPA, was developed in the 1940s as an industrial pothesizer.
“It hardens the plastic,” Cheryl Rosenfeld, professor of veterinary medicine, said. “It replaced glass and revolutionized the plastic industry. The problem is that the structure has a phenolic ring that can look like estrogen to the body. ”
BPA acts as a weak estrogen which can affect homeostasis in the body. Rosenfeld compares homeostasis to a thermostat.
“If it gets too high, it comes back down,” Rosenfeld said. “There’s a regulation to it. With any of these endocrine disruptors, bisphenol A falls into that class, is that they aren’t regulated.”
When BPA infiltrates into your body’s systems, it can locate the receptors that normal estrogen does. This can cause indiscriminate effects. It can go to the brain, affect the immune system, the cardiovascular system and other target organs, Rosenfeld said.
In February of this year, the FDA published a statement concluding that the administration had “…routinely considered and evaluated the scientific evidence surrounding the use of BPA and continues to conclude that BPA is safe for the currently authorized uses in food containers and packaging.”
The FDA had not consulted with any of the researchers collaborating with the project, including Rosenfeld, before releasing the statement, she said.
“If you look back at the statement from February 2018, they said that they’re not seeing any effects with BPA,” Rosenfeld said. “Which we have specifically identified in our study.”
Rosenfeld was able to disprove the FDA’s statement by receiving a grant from the National Institute of Environmental Health Sciences and the National Toxicology Program through the Consortium Linking Academic and Regulatory Insights on BPA Toxicity.
This grant allowed her, along with thirteen other researchers across the country, to analyze the downstream effects of BPA treatments on rats. Rosenfeld specifically researched the neural behavior in the hippocampus and the hypothalamus.
“Those brain regions were specifically chosen for several reasons,” Rosenfeld said. “We had already shown at the same study that BPA affects the hippocampus. So, we designed a behavior test that was specifically geared to assess that brain region.”
The hippocampus is responsible for memorization, so Rosenfeld relates its function as trying to cram for an exam the night before.
In order to test the rats’ memories, they are put through a spatial test called the Barnes Maze. Each rat is assigned to a hole and in order to get the rat to locate their designated hole, a light is shown on them. The light is necessary because rats do not like light, so it causes them to try and escape as quickly as possible. The test takes place over seven days and each time the test is administered, the rat is timed on how long it takes to locate their designated hole.
“Overall, males in the human or the rodent world tend to do better at it than women,” Rosenfeld said. “Especially in the rodent world [and] it makes sense. Their survival is and potential ability to reproduce is dependent on finding their mates.”
The study’s results found that the female rats that were exposed to BPA were acting similarly to the spatial behavior of male rats.
“It improved their spatial navigation ability,” Rosenfeld said. “Which sounds great but the problem is that they are not acting like true females.”
The results of the Barnes Maze became crucial for researching the second brain region, the hypothalamus. The hypothalamus is responsible for social behaviors, such as flirting behaviors, Rosenfeld said.
“All sexual behaviors are coming from this zone so that’s why we looked at the hypothalamus as well,” Rosenfeld said.
In Rosenfeld’s study, the female rats were affected more by the BPA treatment than the male rats. This is called a sexually dimorphic response, which means that males and females are quite different, Rosenfeld said.
“In the rats and mice studies, we had seen more females [affected],” Rosenfeld said.
However, males can also be affected by BPA treatments. Dr. Gail Prins, a professor at the University of Illinois-Chicago, is also one of the fourteen researchers for the CLARITY-BPA grant. Her area of study on the rats is the prostate gland.
“I look at the prostate gland and focus on stem cells,” Prins said. “Also, the way BPA exposure increases susceptibility to hormone-induced cancer.”
Through her research, Prins found that BPA exposure during development, increased the response to estrogen in males as they aged. The male rats produced severe lesions that increased in number when cancer developed, Prins said.
“Other investigators, including Cheryl, have found other organs affected,” Prins said.
In a 2013 study, 15 billion pounds of BPA was produced globally, Rosenfeld said.
“We have a love of plastic so there’s no evidence that it’s going to diminish,” Rosenfeld said. “I’d say we’re hitting 18-20 billion pounds [annually] now.”
Since BPA is a component of plastic, it is now present in the oceans which further affects the environment. As the plastic is heated up, the BPA is leached out.
“It doesn’t bode well to the future,” Prins said. “BPA is already out there, it is in our ecosystem. More is being made everyday and it is breaking down into our food.”
This month, the FDA will be releasing all of the raw data to the public so that anyone can access and analyze it.
“So you have the good and the bad and can make your own interpretations,” Rosenfeld said. “I would like people to recognize that you can’t always just trust government agencies. The FDA is not looking at subtle changes that may be really important. You can’t just look outwardly and see a mutation. It’s something that has to go through a rigorous assessment to find these changes.”
_Edited by Morgan Smith | mosmith@themaneater.com_