Ileal Bile Acid Transporter Inhibitor Improves Hepatic Steatosis by Ameliorating Gut Microbiota Dysbiosis in NAFLD Model MiceOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined whether an ileal bile acid transporter inhibitor (IBATi), a drug developed to treat chronic idiopathic constipation, could improve nonalcoholic fatty liver disease (NAFLD) by acting on the gut microbiota. IBATi increases delivery of bile acids to the colon, and the researchers tested whether this shift in colonic bile acid exposure could alter gut bacteria in a way that benefits the liver. They measured body weight, liver function markers, serum lipids, NAFLD activity scores, and expression of bile-acid-related genes (Cyp7a1 in liver, Fgf15 in ileum) in high-fat diet (HFD) mice treated with IBATi.
Who was studied?
The subjects were mice fed a high-fat diet to induce a NAFLD model, with some receiving IBATi treatment alongside the HFD. Gut microbiota composition was assessed from fecal samples using 16S rRNA sequencing. A separate cohort of antibiotic-treated mice was recolonized through fecal microbiome transplantation (FMT) using stool from either HFD or HFD-plus-IBATi donor mice, allowing the researchers to test whether the microbiota itself could transfer the treatment effect.
What were the most important findings?
IBATi treatment significantly suppressed body weight gain, improved liver dysfunction, lowered serum LDL levels, and reduced NAFLD activity scores compared to untreated HFD mice. It also reversed HFD-induced decreases in hepatic Cyp7a1 and increased ileal Fgf15 expression, both markers of altered bile acid signaling. IBATi changed gut microbiota alpha-diversity that had been reduced by the high-fat diet, and this altered microbiota profile was able to be transferred to antibiotic-treated recipient mice via fecal transplantation.
What are the greatest implications of this study?
The findings suggest that redirecting bile acids to the colon with an ileal bile acid transporter inhibitor can improve hepatic steatosis largely through correction of gut microbiota dysbiosis, rather than through direct liver-only mechanisms. Because the FMT experiments show the microbiota changes themselves reproduce benefits, this supports the gut-liver axis as a therapeutic target for NAFLD. This positions IBATi, an already-used constipation drug, as a potential repurposed candidate for NAFLD treatment pending further research.