P1220 Dysbiosis of the gut microbiota and decreased fecal levels of short-chain fatty acid in patients with Ulcerative Colitis: a hospital-based case-control study

Abstract Background Ulcerative Colitis (UC) is a typical intractable disease whose number of patients is increasing worldwide, and studies have suggested that the gut microbiota and its metabolites are closely involved in its pathogenesis and severity. However, to date, no study has comprehensively compared the microbiomes or metabolomes of UC patients and healthy controls after considering important confounding factors such as age, gender, race, and other lifestyle factors. Therefore, we conducted this clinical study to compare the compositions and diversity of the gut microbiota and the fecal metabolites between age-, sex-, and race-matched patients with Ulcerative Colitis (UC) and those without. Methods In total, 90 outpatients with UC (UC group) and 90 without a history of gastrointestinal diseases and their family members (without UC group) were recruited. Results The UC group had a significantly lower abundance of the genus Bifidobacterium, Faecalibacterium, and Lactobacillus than the without UC group. Furthermore, the UC group had a significantly lower alpha-diversity of the gut microbiota than the without UC group. The UC group had a significantly lower level of fecal SCFAs than the without UC group. These results remained significant after adjusting for sex, age, and smoking status. Furthermore, the expression of a group of genes encoded by the gut bacteria that are involved in the biosynthesis of tetrapyrrole was significantly lower in the UC group than in the without UC group. Conclusion Gut microbiota dysbiosis and low SCFA levels, as well as reduced tetrapyrrole biosynthetic capacity by the gut bacteria, may contribute to the development of UC. Moreover, regardless of the severity, duration, and type of UC, the gut microbiota and its metabolites were in a stable state of dysbiosis in patients with UC.