Safety and Efficacy Study of Human Umbilical Cord Mesenchymal Stem Cells in Preventing Arteriovenous Fistula Stenosis in Patients With End-Stage Diabetic Kidney Disease

Inclusion Criteria: 1. Diabetic nephropathy with estimated glomerular filtration rate (eGFR) \< 15 mL/min·1.73m²; 2. Requirement for creation of primary forearm cephalic vein-radial artery autologous arteriovenous fistula ; 3. Vessel criteria: cephalic vein diameter ≥ 2.0 mm (after tourniquet inflation) and radial artery diameter ≥ 1.5 mm; 4. Subject agrees to comply with the study treatment plan and visit schedule, is voluntarily enrolled, and has provided written informed consent. Exclusion Criteria: 1. Patients with conditions unsuitable for AVF, including surgical site infection, uncontrolled heart failure, malignant tumor, or hypotension; 2. Patients with stenosis or adjacent lesions in the proximal upper extremity vessels or central veins that affect arterial inflow or venous outflow; 3. Patients with a history of pacemaker implantation; 4. Patients with known hypersensitivity to human serum albumin, human platelet lysate, gentamicin sulfate, anesthetic agents, or other related products; 5. Positive for hepatitis B surface antigen, hepatitis C virus antibody, treponema pallidum antibody, or human immunodeficiency virus antibody; 6. Subjects who have participated in, are currently participating in, or plan to participate in other interventional clinical trials within 30 days prior to screening or during the study period; 7. Any other conditions deemed inappropriate by the investigator for enrollment in this study.