RIVERSIDE, Calif. -- Polybrominated diphenyl ethers, or PBDEs, are fire-retardant chemicals that are found everywhere — upholstery, carpets, curtains, electronics, and even infant products. Known to disrupt hormones and persist in the environment, these pollutants have been detected in water, soil, air, food products, animals, human tissues, and even breast milk.
A University of California, Riverside, mouse study published in Archives of Toxicology reports that probiotic supplementation can reduce the negative impacts of PBDEs on neurodevelopment, behavior, and metabolism.
"Exposure to PBDEs during the perinatal period produces autistic-like behavior and metabolism syndrome in mice," said Margarita C. Curras-Collazo , a professor of neuroscience who led the study. "These compounds also disrupt the gut microbiome, which has been linked to brain and metabolic health. Our study shows supplementing the maternal diet with the probiotic Limosilactobacillus reuteri can help prevent these negative effects."
L. reuteri, or LR, typically resides in the digestive tract, where it generates lactic acid. Additionally, it can be found in beans, artichokes, and sweet potatoes, and in fermented foods such as sourdough bread, as well as miso, kimchi, and sauerkraut. It is frequently included in yogurts and other dairy products and, therefore, is readily accessible.
The researchers exposed mouse mothers to a PBDE mixture or a control (corn oil) during pregnancy and breast-feeding. This was done over a ten-week period to model the kind of exposures humans face. Some of the mice were supplemented with LR. The researchers then examined the offspring for developmental benchmarks during the postnatal period and for behavior during adulthood.
They found male offspring exposed to PBDEs had a delay in body weight gain. Further, their incisor eruption was abnormally timed.
"To our surprise, we found LR treatment prevented delays in male weight gain and helped normalize the timing of tooth eruption in both sexes," said Elena Kozlova , a doctoral student working in Curras-Collazo's lab and co-first author on the paper.
According to UCR medical student and co-first author Maximillian Denys , this was a particularly significant result.
"Low birth weight, among other developmental markers, is an established predictor of adult health outcomes," he said. "Sadly, underserved, low socioeconomic populations are disproportionately affected in terms of pollutant exposure and health outcomes."
The research team also found that the exposed female offspring showed exaggerated digging and hyperactivity in adulthood; LR mitigated these effects. Moreover, glucose metabolism and insulin levels improved in adult female offspring exposed to the PBDE mixture that were also given LR directly.
"Maternal probiotic therapy with LR corrected most of the behavioral and metabolic abnormalities caused by PBDE exposure," Kozlova said. "We gave offspring the probiotics through the mother, which is a very effective way to mitigate the effects of PBDEs with low risk to the developing offspring."
According to Curras-Collazo, using gut microbiota-focused therapies before birth through the mother may help protect against developmental and adult diseases linked to toxic exposures. The research team found the PBDE mixture affected the gut microbiome in an age- and sex-dependent way. Maternal LR supplementation promoted the diversity of gut bacteria in female pups and prevented changes in these bacteria in male pups.
"Changes in gut bacteria triggered by probiotics may contribute to these improvements," Curras-Collazo said. "By better understanding how probiotics and environmental toxins interact, we can use these therapies as early interventions to mitigate long-term health problems caused by pollutant transfer from the mother.
"Although our findings must be replicated, they suggest that we can act to safeguard the health of our children against toxic chemicals for which there are no strategies for removal from our bodies," she added. "Perhaps, through probiotics in our diet, we can put our own gut microbiota to work to mitigate toxicant effects and protect our health."
Curras-Collazo, Kozlova, and Denys were joined in the study by other UCR investigators: Rui Liu, Anthony E. Bishay, Elyza A. Do, Varadh Piamthai, Yash V. Korde, Crystal N. Luna, Artha A. Lam, and Dr. Ansel Hsiao.
The study was supported by UC Riverside, UC-Hispanic Serving Institutions Doctoral Diversity Initiative, a Danone North America Gut Microbiome, Yogurt and Probiotics Fellowship Grant, and the National Institutes of Health. The content of this article does not necessarily represent the official views of the National Institutes of Health.
The title of the research paper is "Maternal probiotic supplementation protects against PBDE-induced developmental, behavior and metabolic reprogramming in a sexually dimorphic manner: Role of gut microbiome."
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is more than 26,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual impact of more than $2.7 billion on the U.S. economy. To learn more, visit www.ucr.edu.
