Combination stem cell therapy for the treatment of medically refractory coronary ischemia: a Phase I study

Infusion of a source of endothelial progenitor cells (EPC) into the ischemic myocardium is emerging as a promising therapy for coronary ischemia, probably mediated by the formation of new blood vessels. Studies have shown that while the procedure is safe and feasible, efficacy results are contentious. The investigators hypothesized that the infusion of a combination cell product consisting of a source of EPC and mesenchymal stem cells (MSC) is safe and promotes the formation of more stable and mature blood vessels resulting in improved clinical outcomes.

Ten patients with stable angina pectoris (class III to IV) on maximal medical therapy were included. All patients had ≥ 70% stenosis in at least one coronary artery, and none was considered a candidate for percutaneous coronary intervention or coronary artery bypass graft. End points were feasibility and safety of intracoronary infusion of the combination cell product and assessment of myocardial ischemia, left ventricular ejection fraction (LVEF), and quality of life at 6 months postinfusion.

Six months after cell infusion there were no adverse clinical events. Functional cardiac evaluation during the same period showed significant improvements in LVEF (average increase: 11%, P = .02) and myocardial ischemia (average decrease: 1.8 fold, P = .02). Additionally, all patients described significant improvements in quality of life.

Despite the inherent limitations associated with a Phase I clinical trial, this study demonstrates that the intracoronary infusion of the combination cell product is feasible and safe and also insinuates that this form of therapy may be beneficial.