Fecal Microbiota Transplantation for Type 2 Diabetes Mellitus and Hashimoto's Thyroiditis

Inclusion Criteria:

1. Age ≥ 18 and ≤ 65 years old.
2. Diagnosed with type 2 diabetes mellitus (T2DM).
3. Positive for thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb); thyroid ultrasonography indicates diffuse thyroid lesions.
4. The regimens of hypoglycemic drugs and thyroid-related basic treatments (including drug types and dosages) have remained stable for at least 3 months before enrollment.

Exclusion Criteria:

1. Subjects who have used antibiotics, probiotics or prebiotics within 4 weeks prior to screening.
2. Patients complicated with severe gastrointestinal diseases (e.g., inflammatory bowel disease, active gastrointestinal bleeding).
3. Patients receiving specialized treatment for hyperthyroidism (Graves' disease) or with a history of thyroid malignancy.
4. Patients with severe immunosuppression (neutrophil count < 1500/mm³, lymphocyte count < 500/mm³).
5. Patients with active severe gastrointestinal bleeding, intestinal perforation, or severe intestinal barrier/mucosal injury.
6. Patients with intestinal mucosal injury of unknown etiology.
7. Patients diagnosed with fulminant colitis or toxic megacolon.
8. Patients with active extraintestinal infection requiring treatment with broad-spectrum antibiotics.
9. Severe malnutrition (body mass index < 15 kg/m²) or severe hypoalbuminemia (serum albumin < 25 g/L).
10. Congenital or acquired immunodeficiency diseases.
11. Patients who have recently received high-risk immunosuppressants or cytotoxic drugs (e.g., rituximab, doxorubicin), or medium-to-high dose glucocorticoids (e.g., prednisone >= 20 mg per day for more than 4 consecutive weeks).
12. Patients complicated with other autoimmune diseases.
13. Patients with severe hepatic or renal insufficiency.
14. Patients with malignant tumors.
15. Patients with known allergy to capsule ingredients.
16. Pregnant or lactating females.