Diabetic serum preconditioning augments human umbilical cord mesenchymal stem cell secretome therapeutic efficacy in reversing insulin resistance in 3T3-L1 adipocytes.

BACKGROUND

Insulin resistance, metabolic dysfunction, inflammation, and vascular impairment characterize Type 2 Diabetes Mellitus (T2DM). Mesenchymal stem cells (MSCs) have shown promise in preclinical studies. However, their variable efficacy in human settings warrants strategies to enhance their therapeutic potency. This study evaluates preconditioning of human umbilical cord-derived MSCs (UCMSCs) with diabetic microenvironment (serum) to improve T2DM therapeutic outcomes.

METHODS

Serum from healthy (HS) and newly diagnosed diabetic (DS) donors was characterized for insulin, fasting blood sugar, C-peptide, TNF-α, and IL-6. Human UCMSCs were preconditioned with pooled HS or DS to generate secretomes (UCMSC-S). Assessments included cytokines, cell cycle (PI staining), angiogenesis (yolk sac membrane assay), lipid accumulation (Oil Red O in 3T3-L1 adipocytes), glucose uptake (2-DG), phospho-IRS-1 (Ser307), gene expression (qRT-PCR for Pparg, Slc2a4, Ikbkb), ROS (FACS) in dexamethasone and TNF-α-induced insulin-resistant 3T3-L1 adipocytes,

RESULTS

DS increased UCMSCs metabolic activity and S-phase progression, indicating increased metabolic activity and DNA synthesis. DS-UCMSC-S exhibited reduced levels of IL-6, IL-8, TNF-α and M-CSF, increased levels of G-CSF, GM-CSF, HGF, SCF, and FGF-basic and promoted angiogenesis. In insulin-resistant adipocytes, DS-UCMSC-S markedly reduced lipid accumulation, restored glucose uptake via decreased phospho-IRS-1 (Ser307) expression, and attenuated intracellular ROS generation. Additionally, DS-UCMSC-S significantly up-regulated Pparg, Slc2a4 while down-regulating Ikbkb expression, indicating restoration of metabolic and inflammatory pathways.

CONCLUSION

Diabetic serum preconditioning enhanced the potential of UCMSC-S in reducing lipid accumulation and reversing insulin resistance. DS-UCMSC-S demonstrated potent anti-inflammatory, pro-angiogenic, antioxidant, and insulin-sensitizing effects, highlighting its potential as a disease-adapted, cell-free therapeutic strategy for T2DM.