New research has shown that the link between per- and polyfluoroalkyl substances, or PFAS, and kidney damage may be related to dysregulation of the gut microbiome, which consists of bacteria and other microorganisms that live in the digestive tract.
PFAS are manufactured chemicals used in a wide range of products, including everything from furniture to food packaging. They are often called ‘forever chemicals’ because once they accumulate in the environment or the human body, they take a very long time to break down.
The group of chemicals is known to increase the risk of a range of health problems, including cardiovascular disease, cancer and chronic kidney disease, but the biological mechanisms behind that risk are poorly understood.
“Almost everyone has PFAS in their blood, and these chemicals have been linked to a number of negative health effects. But we have no known interventions to reduce PFAS in the body, so we can’t really make recommendations to help.” said Hailey Hampson, Ph.D., a postdoctoral researcher in population and public health sciences at the Keck School of Medicine of USC, who is lead author of the new study.
Findings from the research are beginning to connect the dots between that problem and possible solutions. Building on previous studies linking kidney damage to both PFAS and intestinal problems, the research team analyzed the three factors together for the first time.
They found that increased exposure to PFAS was associated with worse kidney function four years later, and that changes in the gut microbiome and related metabolites explained up to 50% of that decline in function. The results were published in the news Science of the total environment.
The findings, which add to other Keck School of Medicine studies on PFAS, including longitudinal research, provide early clues on how to protect the kidneys from PFAS-related damage.
“Our findings provide an important piece of the puzzle about the many different health risks of PFAS, which can provide policymakers with information that helps them develop policies to protect the public from exposure to these chemicals,” said Jesse A. Goodrich, Ph. D. ., assistant professor of population and public health sciences at the Keck School of Medicine and senior author of the study.
Declining kidney function
The researchers analyzed data from 78 participants, ages 17 to 22, who took part in the Southern California Children’s Health Study, a large-scale longitudinal effort to understand the effects of pollution on health; 56% of the sample was Hispanic, a group at high risk for chronic kidney disease.
At baseline, the researchers collected blood and stool samples that allowed them to measure exposure to PFAS, gut microbiome bacteria, and circulating metabolites (these metabolites, many of which are produced by the gut microbiome, are present in the blood). At a follow-up appointment four years later, the researchers collected a second round of data on kidney function.
They found that when PFAS exposure increased by one standard deviation, kidney function was 2.4% worse at the follow-up visit. The researchers then conducted a statistical analysis to determine whether a third factor – gut bacteria and related metabolites – contributed to that association.
The analysis revealed two distinct groups of bacteria and metabolites that helped explain the effect of PFAS exposure on kidney function. One group explained 38% of the change in kidney function, and one group explained 50% of the change. Both groups of bacteria and metabolites performed beneficial activities, such as reducing inflammation in the body, that were hampered as PFAS exposure increased.
“We saw that PFAS exposure potentially changed the composition of the microbiome, associated with lower levels of beneficial bacteria and lower anti-inflammatory metabolites,” Hampson said.
A roadmap for future work
The findings provide a roadmap for researchers looking to better understand the link between PFAS and kidney health. Hampson and her colleagues observed a decrease in anti-inflammatory metabolites, as well as the bacteria that produce them, and an increase in inflammatory metabolites.
“This points to inflammation and oxidative stress as a potential mechanism, so that is an area where future research can focus,” she said.
A limitation of the study is the small sample size. Larger studies are needed to determine if and how the findings can be used to protect against PFAS-induced kidney damage, Goodrich said.
Next, the research team will move beyond measuring metabolites in the blood to detecting their presence in specific body tissues, including in the kidneys.
More information:
Hailey E. Hampson et al, The potential mediating role of the gut microbiome and metabolites in the association between PFAS and renal function in young adults: a proof-of-concept study, Science of the total environment (2024). DOI: 10.1016/j.scitotenv.2024.176519 linkinghub.elsevier.com/retrie … ii/S0048969724066750
Quote: Study links exposure to PFAS to decline in kidney function via intestinal microbiome (2024, October 17) retrieved on October 20, 2024 from https://medicalxpress.com/news/2024-10-links-pfas-exposure-kidney-function.html
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