Background: Despite timely primary percutaneous coronary intervention (PCI), patients with ST-elevation myocardial infarction (STEMI) remain at high risk of adverse left ventricular remodeling and subsequent heart failure. Regenerative therapy using umbilical cord–derived mesenchymal stem cells (UC-MSCs) offers immunomodulatory, angiogenic, anti-fibrotic, and pro-survival effects that may enhance myocardial recovery through paracrine signaling and cellular differentiation.

Objective: To evaluate the efficacy and safety of intracoronary UC-MSC transplantation in improving left ventricular ejection fraction (LVEF) and reducing infarct size in STEMI patients undergoing primary PCI, and to assess its association with key remodeling biomarkers (IL-10, VEGF, Galectin-3, GATA-4, and Beclin-1).

Methods: In this single-blind randomized controlled trial, 60 STEMI patients post-primary PCI were allocated to receive either intracoronary UC-MSCs (50 × 10⁶ cells; n=30) on days 10–15 post-PCI or guideline-directed medical therapy alone (n=30). Biomarker levels were measured at baseline, day 7, and day 14. Primary outcomes were LVEF and infarct size assessed by cardiac MRI at baseline and 6 months. Secondary outcomes included major adverse cardiovascular events (MACE).

Results: At 6 months, the UC-MSC group demonstrated significant improvement in LVEF (49.10 ± 10.59; p=0.037). However, infarct size reduction did not significantly differ between groups (p=0.394). VEGF changes showed a moderate positive correlation with LVEF improvement in the intervention group (r=0.40; p=0.027), while no significant correlation was observed with infarct size (r=–0.13; p=0.492). Other biomarkers (IL-10, Galectin-3, GATA-4, Beclin-1) showed no significant association with functional or structural outcomes. No MACE or serious procedurerelated adverse events were reported.

Conclusion: Intracoronary UC-MSC therapy in STEMI patients is safe and associated with modest improvement in ventricular function but does not significantly reduce infarct size. Systemic biomarker changes incompletely reflect myocardial repair dynamics. Larger-scale trials with advanced cell engineering strategies and longer follow-up are warranted to optimize regenerative cardiac therapy

To be updated