Rate- and contractility-modulating drugs, such as adrenergic agonists and antagonists, are widely used in the treatment of cardiovascular conditions. Preclinical assessment of new modulators of rate, inotropy and metabolism can be aided by high-throughput (HT) methods for chronic measurements, coupled with scalable human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Here, we evaluate the utility of long-term optical (label-free) measurements of pericellular oxygen in a HT format (96-well plates) for the assessment of the effectiveness of adrenergic drugs in hiPSC-CMs. Quantitative oxygen consumption metrics were derived and correlated to measurements performed in the same samples using all-optical electrophysiology. Adrenergic agonists significantly increased oxygen consumption rate (OCR), best seen in the kinetics of initial depletion of pericellular oxygen, i.e. time to reach 5%. Adrenergic antagonists decreased OCR, best quantified using steady-state values for pericellular oxygen after at least 5 h. OCR-based drug type identification correlated well with the acute spontaneous rate measurements in the same samples. Direct rate modulation with chronic optogenetic pacing sped up OCR in hiPSC-CMs. Blebbistatin, an excitation-contraction uncoupler, significantly reduced OCR. Computational modeling helped interpret our results by capturing the effects of pacing rate, adrenergic stimulation, and blebbistatin on oxygen consumption, thereby highlighting the key contribution of inotropy and mechanical contraction to OCR in hiPSC-CMs. We conclude that HT label-free optical oxygen measurements and the comprehensive in silico hiPSC-CM models, constrained by such measurements, represent valuable human-based approaches for non-invasive assessment of rate- and metabolism-modulating drugs in preclinical studies.
Li et al. (Tue,) studied this question.