Commentary: isFaecalibacterium prausnitziia potential treatment for maintaining remission in ulcerative colitis?

Abstract

Varela et al. report on the association between levels of Faecalibacterium prausnitzii and maintenance of remission in ulcerative colitis (UC).1 Previous studies have demonstrated lower levels of F. prausnitzii in active UC and Crohn's disease (CD) patients compared to healthy controls.2 This study shows F. prausnitzii numbers to be lower in UC patients in remission than in healthy controls. However, the F. prausnitzii numbers are higher in UC patients who remain in remission than in those who relapse. This study suggests that utilising the anti-inflammatory properties of F. prausnitzii may be a strategy to maintain remission in patients with UC. One area for future research is to determine if the protective effect of F. prausnitzii is associated with its butyrate forming property or its anti-inflammatory property, via secretion of an unidentified substance.3 A second challenge is to determine the optimal strategy for dietary manipulation to increase F. prausnitzii numbers. Studies investigating the effect of inulin,4 fructo-oligosaccharide5 and fibre6 have shown different effects on F. prausnitzii numbers in healthy controls and CD patients. The finding of lower F. prausnitzii numbers in unaffected first-degree relatives of UC patients is interesting, and suggests there are other factors besides environmental that affect gut bacterial composition. A similar study in Crohn's disease patients and their unaffected close contact first-degree relatives demonstrated dysbiosis in the relatives when compared with healthy controls, but the dysbiosis was distinct from that of CD patients.7 This may suggest a role for genetic factors in influencing gut bacterial composition. The interaction between the immune system and gut bacteria in the pathogenesis of UC and CD is a complex one. However, this study suggests F.prausnitzii may have a potential therapeutic role in maintaining remission in UC. Declaration of personal and funding interests: None.