Effect of Once Versus Twice Intracoronary Injection of Allogeneic-Derived Mesenchymal Stromal Cells after Acute Myocardial Infarction: BOOSTER-TAHA7 Randomized Clinical Trial.

Background Mesenchymal stromal cell (MSC) transplantation can improve the left ventricular ejection fraction (LVEF) after an acute myocardial infarction (AMI). Transplanted MSCs exert a paracrine effect, which might be augmented if repeated doses are administered. This study aimed to compare the effects of single versus double transplantation of Wharton’s jelly MSCs (WJ-MSCs) on LVEF post-AMI. Methods We conducted a single-blind, randomized, multicenter trial. After 3–7 days of an AMI treated successfully by primary PCI, 70 patients younger than 65 with LVEF < 40% on baseline echocardiography were randomized to receive conventional care, a single intracoronary infusion of WJ-MSCs, or a repeated infusion 10 days later. The primary endpoint was the 6-month LVEF improvement as per cardiac magnetic resonance (CMR) imaging. Results The mean baseline EF measured by CMR was similar (~ 40%) in all three groups. By the end of the trial, while all patients experienced a rise in EF, the most significant change was seen in the repeated intervention group. Compared to the control group ( n = 25), single MSC transplantation ( n = 20) improved the EF by 4.54 ± 2%, and repeated intervention ( n = 20) did so by 7.45 ± 2% when measured by CMR imaging ( P < 0.001); when evaluated by echocardiography, these values were 6.71 ± 2.4 and 10.71 ± 2.5%, respectively ( P < 0.001). Conclusions Intracoronary transplantation of WJ-MSCs 3–7 days after AMI in selected patients significantly improves LVEF, with the infusion of a booster dose 10 days later augmenting this effect. Trial registration : Trial registration: Iranian Registry of Clinical Trials, IRCT20201116049408N1. Retrospectively Registered 20 Nov. 2020, https://en.irct.ir/trial/52357