Safety and Efficacy of Fecal Microbiota Transplantation on Cognitive Function in T1DM

Inclusion Criteria: 1. According to the definition of type 1 diabetes mellitus (T1DM) by the World Health Organization (WHO), the diagnostic criteria are as follows: (i) clinically diagnosed as T1D by endocrinologists; (ii) insulin dependence from disease onset and diabetic ketoacidosis (DKA)/diabetic ketosis (DK) at diagnosis; (iii) positive for at least one of islet autoantibodies for glutamic acid decarboxylase antibody \[GADA\], insulinoma-associated protein 2 antibody \[IA-2A\], and zinc transporter 8 antibody \[ZnT8A\]; or negative for all three islet autoantibodies, but diagnosed before age 30. 2. Age between 18 and 60 years, with a diabetes duration of 10 years or more 3. Glycated hemoglobin levels ranging from 6.5% to 9.0%. Exclusion Criteria: 1. Use of any hypoglycemic medication other than insulin in the two months prior to randomization. 2. Participation in other clinical trials within the two months prior to randomization. 3. Use of antimicrobial drugs, probiotics, intestinal microbiota regulators, and other drugs with significant impact on gut microbiota within the two months prior to randomization. 4. Gastrointestinal diseases: celiac disease, irritable bowel syndrome, Crohn's disease, etc. 5. Severe infections, severe heart, liver, kidney diseases, tumors, and other inflammatory or autoimmune diseases. 6. Pregnant or lactating women, or women planning pregnancy during the study period. 7. Severe mental health disorders such as schizophrenia, major depression, bipolar disorder, alcohol or substance abuse, etc. 8. Neurological disorders such as Parkinson's disease, progressive supranuclear palsy, epilepsy, multiple sclerosis, traumatic brain injury, stroke, etc. 9. Post-implantation of metal materials or contraindications for other MRI examinations. 10. Severe episodes of unconscious hypoglycemia within the past two months.