The rapid development of hiPSC-CM technologies provides an unprecedented opportunity to develop human-relevant assay systems for cardiac safety assessment and drug efficacy screenings. Current approaches for the detection of functional cardiotoxicity are highly focused on drug-induced abnormalities in electrophysiology. However, cardiovascular abnormalities can also arise through changes in cardiomyocyte contractility, the most important and best understood function of cardiomyocytes in vivo.
A number of drug classes are associated with changes in contractility (e.g. changes in left ventricular ejection fraction), leading to altered clinical use, label warnings, and drug withdrawal from the market. (Pointon et al, 2015). The ability to quantify contractility in hiPSC-CMs would provide a powerful tool to study drug-induced changes in healthy as well as in diseased hiPSC-CMs (e.g. hypertrophic hiPSC-CMs). However, a physiologically relevant hiPSC-CM contractility platform is not yet established.
The CRACK IT InPulse Challenge funds collaborations between industry, academics and SMEs to solve scientific Challenges, delivering 3Rs and commercial benefits. Currently, the assessment of drug-candidates on cardiac contractility relies exclusively on the use of animals prior to clinical trials. Development of a physiologically relevant and robust cardiac contractility in vitro platform will reduce the reliance on these animal studies and provide a model whereby mechanisms of drug action can be investigated.
To enable assessment of adverse drug-effects on cardiomyocyte contractility the CRACK IT InPulse Challenge aims to generate a physiologically-relevant contractility platform with hiPSC-CMs that are phenotypically ‘mature’ and possess a robust contractile apparatus. To tackle this challenge, Ncardia collaborates with an international consortium of academic groups and SMEs with high expertise in physiology, pharmacology, hiPSC technology and bioengineering. The pharmaceutical company GlaxoSmithKline (GSK) provides expertise into what is needed from the platform in the drug development setting. In this manner, the consortium enables exchange of skills in cell engineering, hardware/software design, readouts and analysis as well as in-kind contributions of compounds and data from the sponsor which enhances the validation of the assay systems.
Phase II of the Challenge, which is almost finalized, includes a blinded multisite study where the contractile responses of Ncardia’s Pluricyte® Cardiomyocytes and non-commercial hiPSC-CMs to a set of positive and negative inotropic compounds are evaluated using innovative 2D/3D engineered assay systems developed by the CRACK IT partners (Table 1). These assay systems can measure real contraction force or simultaneously calcium, contraction and voltage of hiPSC-CMs in a physiologically relevant environment.
Upon finalization of the project, we will have developed cutting-edge technologies and solutions for the assessment of drug-effects on cardiomyocyte contractility. Some preliminary results of the contractility platforms in combination with Pluricyte® Cardiomyocytes are shown in Figure 1.
Table 1. 2D and 3D engineered assay systems used within the CRACK IT InPulse Challenge to assess compound effects on contractility
|CellOPTIQ® Platform (2D)
||Measurement of voltage, calcium, and contraction
||University of Nottingham, University of Glasgow/Clyde Biosciences
|3D Engineered Heart Tissue (EHT)
||UKE Hamburg / EHT Technologies
|Triple Transient Measurement System (2D)
||Simultaneous optical measurement of voltage, calcium, and contraction
||Leiden University Medical Center
Figure 1. A) Negative inotropic effect of Nifedipine on Pluricyte® Cardiomyocyte’s electrical activity and contraction recorded using the CellOPTIQ® system Clyde Biosciences). Left: representative action potential traces for baseline (Black) and nifedipine treated (red) cells. Right: representative contractility traces (same color code as A). B) Positive inotropic effect of digoxin and isoprenaline on Pluricyte® Cardiomyocyte’s contraction force recorded using the EHT Model (EHT Technologies). C) Positive inotropic effect of digoxin on Pluricyte® Cardiomyocytes’ calcium handling and contraction analyzed by optical measurement using the Triple Transient Measurement System (LUMC).
- Mannhardt I et al., Human Engineered Heart Tissue: Analysis of Contractile Force. Stem Cell Reports. 2016 Jul 12; 7(1): 29–42.
- Pointon A et al., Assessment of cardiomyocyte contraction in human-induced pluripotent stem cell-derived cardiomyocytes. Toxicol Sci. 2015 Apr;144(2):227-37.