The following is a summary of “Microbiota DNA Translocation Into Mesentery Lymph Nodes Is Associated With Early Development of Pouchitis After IPAA for Ulcerative Colitis,” published in the November 2023  issue of Gastroenterology by Zhao, et al.

A lot of research has been done on the role of bacterial movement in Crohn’s disease. However, more information is needed about how germs move into the mesentery in people with ulcerative colitis. For a study, researchers sought to find out how bacterial movement affects the result of surgery by looking at the microbiome profile of various body parts in ulcerative colitis patients who had proctocolectomy and IPAA. Samples were taken from 27 people with ulcerative colitis who had IPAA and 15 healthy people who had a regular colonoscopy. What kind of microbes are in different parts of the body, and what happens in the short and long run after IPAA in people with ulcerative colitis? Bacterial DNA was found in the mesenteric lymph nodes of 51.9% of patients with ulcerative colitis (14/27) and mesenteric fat tissue of 66.7% of patients (18/27). 

More like the nasal microbiome than the fecal microbiome was the microbiome in the mesenteric lymph nodes and mesenteric fatty tissue. Within 12 months of IPAA, pouchitis was linked to positive bacterial DNA in mesenteric lymph nodes (8/14 vs 0/13; P = 0.002). The Bray-Curtis distance in mesenteric lymph nodes was also significantly different between patients with pouchitis and those without it (P = 0.009). The study had problems, like a small sample size and no in situ experiments to ensure the bacterial translation was real.

Many people with ulcerative colitis had bacteria move from one place to another. The DNA of bacteria moved between mesenteric fatty tissue and lymph nodes, which were very closely linked and more likely to have come from the nasal microbiome than the fecal microbiome. Also, the amount of bacteria that move around and the movement of certain bacteria may be linked to the early onset of pouchitis after IPAA. Using bacterial samples from mesenteric lymph nodes might be the first time this method has been used to predict pouchitis.