Fecal Microbiota Transplantation for Ulcerative Colitis Using Dai and Han Donors

This study is a randomized clinical trial evaluating fecal microbiota transplantation (FMT) for ulcerative colitis (UC) using healthy donors from two ethnic groups in Yunnan, China. UC is a chronic inflammatory bowel disease causing colon inflammation and ulcers. FMT transfers gut bacteria from a healthy donor to a patient to restore healthy intestinal microbiota. Previous research suggested that FMT using donors from the Dai ethnic group (a minority nationality in Yunnan with special dietary habits) may achieve better results than Han Chinese donors for UC. This study aims to confirm this finding and understand why. The investigators will recruit 200 UC patients (ages 18-60) and randomly assign them to two groups (100 each). One group will receive FMT from healthy Han donors; the other from healthy Dai donors. Patients will receive three FMT infusions via endoscopic intestinal tubing. Treatment effects will be assessed at 12 weeks using clinical scores (Mayo score), endoscopic scores (MES), inflammatory markers (fecal calprotectin, CRP, ESR), and intestinal barrier function tests. Stool samples will also be analyzed using metabolomics and metagenomics to identify key gut bacteria and metabolites linked to better outcomes, and laboratory experiments will be performed to verify how they reduce intestinal inflammation. The goal is to identify optimal donor characteristics for FMT in UC and uncover mechanisms that may lead to more personalized microbiota therapies.

Inclusion Criteria: * Age 18-60 years * Diagnosed with ulcerative colitis (left-sided colitis) according to ECCO guidelines and Chinese Guidelines for the Diagnosis and Treatment of Ulcerative Colitis (2023 Xi'an) * Baseline Mayo score 3-10 * Treated only with mesalazine before and during the study to exclude drug interference Exclusion Criteria: * Pregnancy or planned pregnancy in the near future * Patients in clinical remission (Mayo score ≤2 with no individual subscore \>1) * Development of diseases different from or confounding the initial diagnosis during the study * History of toxic megacolon, perianal disease, or intestinal surgery * Concurrent severe cardiac, pulmonary, or renal disease, or malignancy