Umbilical cord mesenchymal stem cells indicate the therapeutic effects and safety on type 2 diabetes by characteristics of secretion and immune Immunomodulation.

Umbilical cord mesenchymal stem cells can improve insulin resistance of the target tissues, reduce the islet progressive damage, ease or regenerate of the islet beta cells and improve hyperglycemic state of diabetes by secreting a variety of cytokines. It can induce damaged alpha cells differentiate into beta cells in the islet transformation to realize the islet beta cells in situ regeneration by improving microenvironment of islet beta cells. Umbilical cord mesenchymal stem cells also have immunosuppressive effect, it can promote islet cell repair and regeneration by the inhibition of T cell mediated immune response to beta cells.

Inclusion Criteria:

1. 20 ≤ age ≤ 65 years;
2. Duration of type 2 diabetes ≤20 years;
3. 24.0 kg/m2 ≤ BMI ≤40.0 kg/m2;
4. Stable exogenous insulin dose between 0.5-1.0 U/Kg/Day with or without oral hypoglycemic agents (Dipeptidyl peptidase-4 (DPP-4) inhibitor, Glucagon like peptide 1 receptor (GLP-1R) agonist and Sodium-glucose co-transporter 2 (SGLT-2) inhibitor excluded) for at least 3 months;
5. 7.0% ≤ HbA1c ≤ 12.0%;
6. Fasting C-peptide ≥ 1ng/ml;
7. Willingness to participate in the trial.

Exclusion Criteria:

1. Patients with ketonuria, tumor, serum creatinine level more than 175μmol/L, myocardial infarction in the previous year, current angina or heart failure, more than one major vascular event, retinopathy requiring laser treatment, malignant hypertension, uncorrected endocrine disorder, occupations precluding insulin therapy;
2. Severe concurrent illness limiting life expectancy, inadequate understanding of the study protocol, drug abuse, pregnant willing and allergic constitution.

All investigators and participants were masked to treatment allocation. The independent data monitoring committee and the statisticians supporting the committee's activities were the only people with access to unblinded data.