In situ monitoring reveals cellular environmental instabilities in human pluripotent stem cell culture

Mammalian cell cultures are a keystone resource in biomedical research,
but the results of published experiments often suffer from reproducibility
challenges. This has led to a focus on the influence of cell culture
conditions on cellular responses and reproducibility of experimental
findings. Here, we perform frequent in situ monitoring of dissolved O2 and
CO2 with optical sensor spots and contemporaneous evaluation of cell
proliferation and medium pH in standard batch cultures of three widely
used human somatic and pluripotent stem cell lines. We collate data from
the literature to demonstrate that standard cell cultures consistently
exhibit environmental instability, indicating that this may be a pervasive
issue affecting experimental findings. Our results show that in vitro cell
cultures consistently undergo large departures of environmental parameters
during standard batch culture. These findings should catalyze further
efforts to increase the relevance of experimental results to the in vivo
physiology and enhance reproducibility.