Microbial butyrate capacity is reduced in inflamed mucosa in patients with ulcerative colitis

Reduced butyrate-production capacity has been reported in fecal microbial communities in patients with active ulcerative colitis. However, the butyrate-production capacity of the mucosal microbiome from active vs quiescent mucosa in ulcerative colitis has been unexplored. We sought to determine the diversity and relative abundance of mucosal bacterial and fungal communities from endoscopically active vs quiescent mucosa in patients with UC, and aimed to predict contributions of mucosal microbial communities to butyrate synthesis. Systematic, segmental right- and left-sided biopsies were obtained from endoscopically active (n = 13) or quiescent (n = 17) colonic mucosa, among 15 patients with pan-colonic ulcerative colitis. Dietary fiber intake of patients was performed using the validated five-item FiberScreen questionnaire. Amplicon sequencing of mucosal bacteria and fungi was performed. The diversity and relative abundance of mucosal bacterial and fungal taxa were quantified, and predicted contributions to butyrate synthesis were ascertained. Bacterial alpha and beta diversity were similar between active vs quiescent mucosa. Butyrogenic taxa were significantly increased in quiescence, including Butyricimonas, Subdoligranulum, and Alistipes. Predicted butyrate kinase activity was significantly and concomitantly increased in quiescent mucosa. Fiber intake was positively correlated with butyrogenic microbes. Compared to mucosal bacterial prevalence, mucosal fungi were detected in low prevalence. Butyrogenic microbes are relatively increased in quiescent mucosa in ulcerative colitis, and may be related to increased fiber intake during quiescence. Manipulation of the mucosal microbiome towards butyrate-producing bacteria may be associated with endoscopic quiescence.

The impact of recipient and donor gender-match and mismatch on the post-liver transplant outcomes of patients with primary biliary cholangitis

BACKGROUND & AIMS

In this study, we evaluate the effects of donor gender on post-liver transplant (LT) prognosis. We specifically consider patients with primary biliary cholangitis (PBC).

METHODS

The 2005 to 2019 UNOS transplant registry was used to select patients with PBC. The study cohort was stratified by donor gender. All-cause mortality and graft failure hazards were compared using iterative Cox regression analysis. Subanalyses were performed to evaluate gender mismatch on post-LT prognosis.

RESULTS

There were 1885 patients with PBC. Of these cases, 965 entries had male donors and 920 had female donors. Median follow-up was 4.82 (25-75% IQR 1.83-8.93) years. Having a male donor was associated with higher all-cause mortality (aHR 1.28 95%CI 1.03-1.58) and graft failure (aHR 1.70 95%CI 1.02-2.82). Corresponding incidence rates were also relatively increased. In the sub-analysis of female recipients (n = 1581), those with gender-mismatch (male donors, n = 769) were associated with higher all-cause mortality (aHR 1.41 95%CI 1.11-1.78) but not graft failure. In the male recipient subanalysis (n = 304), no associations were found between gender-mismatch (female donors, n = 108) and all-cause mortality or graft failure.

CONCLUSION

This study shows that recipients who have male donors experienced higher rates of all-cause mortality following LT. This finding was consistent in the female recipient-male donor mismatch cohort.