Mesenchymal stem cell therapy for type 2 diabetes: mechanisms, clinical evidence, and future directions.

Type 2 diabetes mellitus (T2DM) is a global public-health challenge characterized by insulin resistance, progressive β-cell dysfunction, and chronic low-grade inflammation. Conventional therapies often control glycaemia but do not consistently prevent disease progression or complications. Mesenchymal stem cells (MSCs), derived from bone marrow, adipose tissue, and the umbilical cord, have been investigated for T2DM due to their immunomodulatory and paracrine regenerative properties. Preclinical studies and early-phase clinical trials (2000-2025) have reported modest improvements in glycaemic indices, including mean reductions in HbA1c and decreases in exogenous insulin requirements in some cohorts, rather than the uniform 1-2% reduction previously stated. Signals of benefit have also been described in diabetic complications such as nephropathy and wound healing. However, these findings derive largely from small, heterogeneous studies with short follow-up, and should therefore be interpreted cautiously. Recent strategies to enhance MSC efficacy (for example, genetic modification such as OCN-19 overexpression) show preliminary promise but require more rigorous evaluation. Key challenges that currently limit clinical translation include variability in MSC sources and manufacturing, impaired cell function in the diabetic microenvironment, small and underpowered trials, and limited long-term safety and cost-effectiveness data. This review synthesizes mechanistic and clinical evidence for MSC therapy in T2DM, highlights recent technological advances, and outlines priorities for future research, notably standardized GMP-compliant production, robust randomized multicenter trials with long-term follow-up, and the development of predictive biomarkers to identify likely responders and optimize patient selection.