Researchers tested engineered heart muscle (EHM) allografts in rhesus macaques to evaluate their potential for heart repair. The study examined whether allografts derived from induced pluripotent stem cell cardiomyocytes and stromal cells could integrate into failing hearts while avoiding major side effects.
To assess long-term function, macaques received EHM grafts ranging from 40 to 200 million cells. Over six months, grafts remained in place and contributed to increased heart wall thickness and contractility. Gadolinium-based MRI confirmed vascularization, suggesting functional integration. In macaques with heart failure, ejection fraction improved, indicating enhanced cardiac output. Importantly, no signs of tumor formation or persistent arrhythmias were detected.
These findings contributed to the approval of a first-in-human clinical trial. In an initial patient with advanced heart failure, EHM implantation confirmed structural remuscularization.
