BPA replacement, BPS, hinders heart function, study reveals

BPA replacement, BPS, hinders heart function, study reveals

BPA's counterpart replacement BPS can hinder heart function within minutes of a single exposure, according to a new University of Guelph study.

The study is the first to show the instant effects bisphenol S (BPS) can have on the heart.

"We expected to find similar effects from BPS as we have with BPA, but not at the speed that it worked," said biomedical sciences professor Glen Pyle, who conducted the study with former master's student Melissa Ferguson. "This replacement chemical seems to be more potent."

Bisphenol A (BPA), a chemical used in plastic products, was banned from baby bottles in Canada in 2010 over concerns that it may leach into foods and cause hormone-related side effects. More manufacturers are now using BPS as a replacement in their products and labelling them as BPA-free.

When mice were given bisphenol BPA or BPS in amounts that mimicked typical human levels, their heart function worsened, especially in females, within minutes of exposure.

These findings are concerning, as endocrine receptors and metabolic pathways are similar in mice and humans, said Pyle.

"This study raises concerns about the safety of BPS as a replacement for BPA."

It's particularly worrisome for people with coronary heart disease, high blood pressure, diabetes or obesity, because the effects of BPS could increase the chance of a heart attack or make a heart attack more severe, he added.

"If the heart is in a precarious position, when you add a stressor you can make it worse."

Published recently in the journal Scientific Reports, the study entailed treating mouse hearts with BPA and BPS at levels typically seen in people. Each chemical on its own was found to depress heart function by dampening heart contractions causing slower blood flow. However, BPS had a quicker impact -- within five minutes of exposure.

"Previous research has looked at the chronic effects that can happen when exposed to BPS over days," said Pyle. "But we are the first to show how fast BPS can work. This is an important finding because it means you don't need to have a buildup of the chemical over time to experience its harmful effects."

BPA is found in plastics used for food packaging, including liners for metal cans and other containers, as well as in medical devices such as hospital intravenous lines and dental sealants.

Although the body gets rid of bisphenols quickly, their ubiquitous use in so many consumer goods means that the substance persists.

Pyle advocates banning the substitute chemical BPS from such consumer products as food and beverage packaging, toys and thermal paper receipts. He also suggests consumers reduce plastic use, including single-use plastics.

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Materials provided by University of Guelph. Note: Content may be edited for style and length.

MRI reveals brain damage in obese teens

Researchers using MRI have found signs of damage that may be related to inflammation in the brains of obese adolescents, according to a study being presented next week at the annual meeting of the Radiological Society of North America (RSNA).

Obesity in young people has become a significant public health problem. In the U.S., the percentage of children and adolescents affected by obesity has more than tripled since the 1970s, according to the Centers for Disease Control and Prevention. Data from the World Health Organization indicates that the number of overweight or obese infants and young children ages five years or younger increased from 32 million globally in 1990 to 41 million in 2016.

While obesity is primarily associated with weight gain, recent evidence suggests that the disease triggers inflammation in the nervous system that could damage important regions of the brain. Developments in MRI like diffusion tensor imaging (DTI), a technique that tracks the diffusion of water along the brain's signal-carrying white matter tracts, have enabled researchers to study this damage directly.

For the new study, researchers compared DTI results in 59 obese adolescents and 61 healthy adolescents, ages 12 to 16 years. From DTI, the researchers derived a measure called fractional anisotropy (FA), which correlates with the condition of the brain's white matter. A reduction in FA is indicative of increasing damage in the white matter.

The results showed a reduction of FA values in the obese adolescents in regions located in the corpus callosum, a bundle of nerve fibers that connects the left and right hemispheres of the brain. Decrease of FA was also found in the middle orbitofrontal gyrus, a brain region related to emotional control and the reward circuit. None of the brain regions in obese patients had increased FA.

"Brain changes found in obese adolescents related to important regions responsible for control of appetite, emotions and cognitive functions," said study co-author Pamela Bertolazzi, a biomedical scientist and Ph.D. student from the University of São Paulo in Brazil.

This pattern of damage correlated with some inflammatory markers like leptin, a hormone made by fat cells that helps regulate energy levels and fat stores. In some obese people, the brain does not respond to leptin, causing them to keep eating despite adequate or excessive fat stores. This condition, known as leptin resistance, makes the fat cells produce even more leptin.

Worsening condition of the white matter was also associated with levels of insulin, a hormone produced in the pancreas that helps regulate blood sugar levels. Obese people often suffer from insulin resistance, a state in which the body is resistant to the effects of the hormone.

"Our maps showed a positive correlation between brain changes and hormones such as leptin and insulin," Dr. Bertolazzi said. "Furthermore, we found a positive association with inflammatory markers, which leads us to believe in a process of neuroinflammation besides insulin and leptin resistance."

Dr. Bertolazzi noted that additional studies are needed to determine if this inflammation in young people with obesity is a consequence of the structural changes in the brain.

"In the future, we would like to repeat brain MRI in these adolescents after multi-professional treatment for weight loss to assess if the brain changes are reversible or not," she added.

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Materials provided by Radiological Society of North America. Note: Content may be edited for style and length.