Effects of Human Plasma-Like Medium on hPSC-derived cardiomyocytes in vitro

However, widely used basal medium such as RPMI contain non-physiological compositions that limit their relevance to human cardiac physiology. In this study we introduced Human Plasma-Like Medium (HPLM) as a better basal medium supplemented with B27, a physiologically tailored alternative designed to systematically replicate the salt concentrations and polar metabolite profiles of adult human plasma.

Starting with Day16 hPSC-CMs, we cultured cells for two weeks in HPLM/B27 or control media (standard and low-glucose [5 mM] RPMI/B27) and assessed maturation outcomes at Day30. Compared to standard and low-glucose RPMI/B27, HPLM/B27 significantly enhanced hPSC-CM maturity across transcriptomic, structural, functional, and metabolic aspects. These improvements included accomplished myosin heavy chain isoform switching (MYH6 to MYH7), accelerated ventricular-specific myosin light chain isoform switching (MLC2a to MLC2v), elongated sarcomeres (~2.07 µm), enhanced calcium transient kinetics, and coordinated activation of oxidative and glycolytic metabolism.