Bone marrow mesenchymal stem cell and mononuclear cell combination therapy in patients with type 2 diabetes mellitus: a randomized controlled study with 8-year follow-up

To investigate the long-term effects of combining bone marrow mesenchymal stem cells (MSCs) with mononuclear cells (MCs) in the treatment of type 2 diabetes mellitus (T2DM). T2DM patients were divided into the combination group (Dual MSC + MC, n = 33), the mononuclear cell group (MC-Only, n = 32) and the control group (Control, n = 31). All groups were treated with insulin and metformin. The Dual MSC + MC group additionally received MSC and MC infusion and the MC-Only group additionally received MC infusion. The patients were followed up for 8 years. The primary endpoint was the C-peptide area under the curve (C-p AUC) at 1 year. This study was registered with clinicaltrial.gov (NCT01719640). A total of 97 patients were included and 89 completed the follow-up. The area under the curve of C-peptide of the Dual MSC + MC group and the MC-Only group was significantly increased (50.6% and 32.8%, respectively) at 1 year. After eight years of follow-up, the incidence of macrovascular complications was 13.8% (p = 0.009) in the Dual MSC + MC group and 21.4% (p = 0.061) in the MC-Only group, while it was 44.8% in the Control group. The incidence of diabetic peripheral neuropathy (DPN) was 10.3% (p = 0.0015) in the Dual MSC + MC group, 17.9% (p = 0.015) in the MC-Only group, and 48.3% in the Control group. The combination of MSC and MC therapy can reduce the incidence of chronic diabetes complications and improves metabolic control with mild side effects in T2DM patients.