Bisphenol-A, a compound used in the production of some plastics and resins that line containers of canned foods and beverages, was seen to worsen symptoms and increased mortality in a mouse model of ulcerative colitis, a type of inflammatory bowel disease (IBD), raising concerns about its potential effects on people.
The compound, also known as BPA, was found to affect mice body weight, stool consistency and rectal bleeding, and to increase gut inflammation and mortality, researchers reported.
Their study, “Bisphenol-A alters microbiota metabolites derived from aromatic amino acids and worsens disease activity during colitis,” was published in the journal Experimental Biology and Medicine.
Although the exact causes of the different forms of IBD, including ulcerative colitis and Crohn’s disease, are largely unknown, physicians and researchers have identified a number of potential environmental risk factors. These include smoking, diet, infections, toxins and medications.
Estrogen, a hormone responsible for the development and regulation of the female reproductive system, is also considered a risk factor for IBD. Bisphenol-A can act as estrogen in the body, but it effects on IBD were not yet discovered.
Since humans are exposed to high levels of BPA through the use of plastic containers and the consumption of canned foods, researchers at Texas A&M University studied the effect of the compound on the exacerbation of inflammation in the colon (a part of the gut) and on the type of amino acids produced by the gut microbiome (microorganisms living in the gut) in a mouse model of colitis.
In this experiment, mice were exposed to BPA levels of 50 µg/kg/day, which were found to exacerbate acute intestinal inflammation. The dose is the reference dose established by the Environmental Protection Agency.
“While this dose is in the upper end of what is estimated for human exposures to BPA, it results in circulating BPA concentrations in C57BL/6 mice [the animals used in this study] within the range of that observed in humans,” researchers wrote.
Results showed that this dose of bisphenol-A both killed the mice and worsened their disease activity, seen as a decrease in body weight and stool consistency, and an increase in rectal bleeding and colon inflammation.
Researchers also found that the compound reduced the levels of the amino acid tryptophan and other molecules associated with lower inflammation in the colon.
“This is the first study to show that bisphenol-A can negatively impact gut microbial amino acid metabolism in a way that has been associated with IBD,” Jennifer DeLuca, graduate student and first author of the study, said in a press release.
Added Steven R. Goodman, the journal’s editor-in-chief, this work “provided evidence in an acute dextran sulfate sodium-induced colitis mouse model that bisphenol-A may be associated with increased colonic inflammation and inflammatory bowel disease. These findings warrant future mechanistic studies.”