High and intermittent hydrostatic pressure promotes maturation of engineered cardiac tissues derived from human pluripotent stem cells

The immaturity of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) and engineered cardiac tissues (ECTs) limits their use in regenerative therapies. Ventricular loading pressure plays a vital role in cardiac repair, prompting the hypothesis that hydrostatic pressure could enhance ECT maturation. ECTs were created by co-culturing hPSC-derived cardiovascular cells with extracellular matrix proteins and subjecting them to intermittent hydrostatic pressure (1 hour/day at 50 kPa for 3 days after 2 weeks of pre-culture). This protocol improved cardiomyocyte alignment, mitochondrial content, and metabolic and functional maturation, evidenced by enhanced contractility, calcium flux, and single-cell RNA sequencing. Endothelial cells were critical for these effects, as their absence prevented maturation. Hydrostatic pressure combined with dynamic culture also promoted vascular network formation. Transplanted trained ECTs significantly improved ejection fraction in a rat myocardial infarction model. These findings demonstrate the potential of hydrostatic pressure training to advance ECT maturation and therapeutic application.