Altered fecal bile acid composition in active ulcerative colitis Original paper

What was studied?

This study investigates the relationship between fecal bile acid composition and inflammatory bowel disease (IBD), particularly focusing on ulcerative colitis (UC) and Crohn’s disease (CD). Researchers sought to identify specific bile acid species that are altered in active disease and whether these alterations correlate with markers of disease severity such as fecal calprotectin and C-reactive protein (CRP). The aim was to explore if bile acid profiles could serve as potential biomarkers for distinguishing between IBD subtypes and assessing disease activity.

Who was studied?

The study included 62 patients with IBD (38 with CD and 24 with UC) and 17 healthy controls. The IBD patients were assessed based on clinical diagnosis and disease activity, with markers such as fecal calprotectin and CRP used to measure inflammation. Stool samples were collected from all participants, and the bile acid composition was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Most important findings

The study found that IBD patients exhibited significant alterations in fecal bile acid composition compared to healthy controls. Notably, UC patients had lower levels of secondary bile acids, such as deoxycholic acid (DCA) and lithocholic acid (LCA), and a higher proportion of primary bile acids like cholic acid (CA) and chenodeoxycholic acid (CDCA). In contrast, CD patients showed increased levels of secondary bile acids. Specifically, UC patients had a decreased ratio of secondary to primary bile acids compared to controls, suggesting impaired bile acid metabolism. In UC, a negative correlation was observed between the levels of certain bile acids (such as hyodeoxycholic acid and glycolithocholic acid) and fecal calprotectin, a marker of mucosal inflammation. However, in CD patients, bile acid levels did not correlate with inflammation markers. The study also identified that bile acid composition could potentially distinguish between UC and CD, with specific bile acids like GHDCA and GCDCA showing diagnostic potential for UC.

Key implications

The altered fecal bile acid composition in IBD patients, particularly UC, offers insight into the underlying metabolic disturbances associated with disease activity. This finding highlights the potential of bile acids as non-invasive biomarkers for IBD, specifically for distinguishing between UC and CD. The correlation between bile acid levels and disease markers like fecal calprotectin suggests that bile acid profiles could also serve to monitor disease activity and assess treatment responses, particularly in UC. Further studies are needed to confirm the clinical validity of these biomarkers and to explore their therapeutic potential, such as modulating bile acid metabolism to improve disease outcomes. Additionally, these findings could contribute to the development of personalized treatment strategies based on bile acid profiles.