PFAS exposure alters gut microbiota metabolites associated with hepatic metabolism: a pilot study

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that can disrupt human hepatic metabolism both directly and through alterations of the gut microbiota. However, the contribution of microbiota-mediated mechanisms to PFAS-induced hepatic dysfunction remains poorly understood. Here, we investigated how PFAS-modified gut microbial metabolites affect human hepatocyte metabolism using an in vitro colon fermentation model, supported by an in vivo mouse and in vitro human hepatocyte exposure studies. PFAS exposure altered the fecal metabolome in human colonic fermentations, particularly affecting pathways related to fatty acid, amino acid, vitamin, and mitochondrial metabolism. Fecal metabolomics from PFOA-exposed mice showed overlapping pathway-level alterations, including effects on fatty acid, bile acid, and steroid hormone metabolism, supporting the biological relevance of the in vitro findings. Exposure of HepaRG hepatocytes to control fermentation extracts markedly altered lipid profiles, confirming that gut-derived metabolites actively regulate hepatic metabolism. Notably, PFAS-exposed fermentation extracts induced distinct hepatocyte metabolic changes compared with PFAS-spiked control extracts, indicating effects driven by PFAS-modified microbial metabolites rather than direct PFAS carry-over. These changes included decreased acyl-carnitines and increased L-carnitine, consistent with altered fatty acid transport and mitochondrial β-oxidation. PFAS-modified extracts also altered bile acids, steroid metabolites, inosine, and sialic acid derivatives, suggesting broader alteration of bile acid signaling, endocrine-related metabolism, purine metabolism, glycoprotein turnover, and lipid-glucose homeostasis. These findings from our pilot study demonstrate that PFAS exposure reshapes gut microbial metabolite profiles with downstream consequences for hepatocyte metabolism. Our findings provide new mechanistic insight into how PFAS may contribute to metabolic disorders.