The Suppression of Medium Acidosis Improves the Maintenance and Differentiation of Human Pluripotent Stem Cells at High Density in Defined Cell Culture Medium

We use a chemically defined medium to systemically examine cellular activities and the impact of medium components in high-density culture. We show that medium acidosis is the main factor that alters cell cycle, gene expression and cellular metabolism at high cell density. The low medium pH leads to inhibition of glucose consumption, cell cycle arrest, and subsequent cell death. At high cell density, the suppression of medium acidosis with sodium bicarbonate (NaHCO3) significantly increases culture capacity for stem cell survival, derivation, maintenance and differentiation. Total RNA obtained from high density (HD) and low density (LD) embryonic stem cell culture subjected to no treatment (ctrl) or treatment with sodium bicarbonate (bicarb). Samples were collected on day 2 (D2).