Efficacy and Safety of Whartons Jelly-Derived Mesenchymal Stem Cells in Patients with Ischemic Cardiomyopathy: A Randomized Pilot Trial

Introduction Whartons jelly-derived mesenchymal stem cells (WJ-MSCs) have emerged as a promising regenerative strategy for ischemic heart disease because of their immunomodulatory, angiogenic, and antifibrotic properties. This pilot randomized trial evaluated the safety, feasibility, and exploratory efficacy of intramyocardial WJ-MSC administration combined with an extracellular matrix (ECM) patch in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting (CABG). Methods In this randomized, controlled pilot trial, 28 patients with ischemic cardiomyopathy, left ventricular ejection fraction (LVEF) <40%, and viable myocardium on cardiac magnetic resonance imaging (MRI) were assigned to receive intramyocardial WJ-MSC injections plus an extracellular matrix (ECM) patch or a placebo patch. Patients were followed for 12 months with echocardiography, cardiac MRI, Holter monitoring, functional assessment, and quality-of-life evaluation. Results Among 44 screened patients, 28 were randomized (16 to WJ-MSC and 12 to control). At 12 months, echocardiography showed a greater improvement in LVEF in the WJ-MSC group than in the control group (8% vs. 0%, p=0.045). Myocardial fibrosis decreased by 32% in both groups. Cardiac MRI demonstrated improvement in both groups, with numerically greater gains in LVEF and larger reductions in fibrosis in the WJ-MSC arm, although between-group differences were not statistically significant. No significant between-group differences were observed in ventricular arrhythmias or serious adverse events. Two non-cardiac postoperative deaths occurred in the WJ-MSC group. Conclusions Intramyocardial WJ-MSC administration combined with an ECM patch during CABG appears feasible and safe, with signals of functional improvement. Larger, adequately powered trials are needed to confirm efficacy and long-term safety.