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Contractility of the myocardium engines the pumping function of the heart and is enabled by the collective contractile activity of its muscle cells: cardiomyocytes. The effects of drugs on the contractility of human cardiomyocytes in vitro can provide mechanistic insight that can support the prediction of clinical cardiac drug effects early in drug development. Cardiomyocytes differentiated from human-induced pluripotent stem cells have high potential for overcoming the current limitations of contractility assays because they attach easily to extracellular materials and last long in culture, while having human- and patient-specific properties. Under these conditions, contractility measurements can be non-destructive and minimally invasive, which allow assaying sub-chronic effects of drugs. For this purpose, the function of cardiomyocytes in vitro must reflect physiological settings, which is not observed in cultured cardiomyocytes derived from induced pluripotent stem cells because of the fetal-like properties of their contractile machinery. Primary cardiomyocytes or tissues of human origin fully represent physiological cellular properties, but are not easily available, do not last long in culture, and do not attach easily to force sensors or mechanical actuators. Microengineered cellular systems with a more mature contractile function have been developed in the last 5 years to overcome this limitation of stem cell–derived cardiomyocytes, while simultaneously measuring contractile endpoints with integrated force sensors/actuators and image-based techniques. Known effects of engineered microenvironments on the maturity of cardiomyocyte contractility have also been discovered in the development of these systems. Based on these discoveries, we review here design criteria of microengineered platforms of cardiomyocytes derived from pluripotent stem cells for measuring contractility with higher physiological relevance. These criteria involve the use of electromechanical

We compared a published computational model of the action potential of a specific type of human induced pluripotent stem cell -derived cardiomyocytes (hiPSC-CM) with experimental field potential data with regard to their inter-beat interval and the duration of repolarization. In particular, concomitant changes in inter-beat interval and duration of repolarization were calculated after reduction and/or augmentation of specific ion channel conductances as a surrogate for pharmacological manipulation. The observed mismatches between calculations and experimental data indicate that there is information missing about the cellular test system. Based on our results we hypothesize that, among other currents, the actual If (“funny current”) may deviate from the prediction. We show that replacement of the If formulation by alternative equations causes the model predictions to change qualitatively, however, none of the available formulations is actually achieving a satisfactory match with experimental data. We suggest a strategy to clarify whether the mismatch can be completely resolved at all using single cell models and, if yes, how this goal could be reached

Southern Africa (South Africa as well as neighboring countries) has not had an infrastructure for testing the safety of new drugs or other therapeutic entities, including plant-based or herbal treatments coming from the indigenous cultures, according to the current practice and regulatory requirements. Simultaneously, Southern Africa is challenged by very high rates of immune deficiency diseases which have further led to the resurgence of diseases such as tuberculosis, which is commonly thought to be eradicated, at least in Western cultures. Thus, there is high medical need for affordable, effective and safe treatments, but up to now there has been no local expertise and capabilities for state-of-the-art drug testing. Based on an initiative funded by the South African Department of Science and Technology, the Potchefstroom campus of North-West University was chosen for the establishment of a center of excellence for doing rodent-based drug testing research. The centerpiece of the Pre-Clinical Drug Development Platform (PCDDP) is a new rodent vivarium for breeding of SPF rats and mice and associated laboratories for conducting a wide range of physiological and pharmacological studies. Notably, the vivarium has become the first AAALAC-accredited animal facility in Sub-Sahara Africa and is qualified for conducting GLP studies. The establishment of safety pharmacology models is a first priority of the PCDDP, including expertise in studies to examine electrophysiological effects in vitro, and potential CNS, cardiovascular and respiratory effects. The intention is to offer the rodent-based safety pharmacology testing not only to local academic and company-related scientists, but also to those throughout South Africa and neighboring countries

Introduction The sensitivity of a given test to detect a treatment-induced effect in a variable of interest is intrinsically related to the variability of that variable observed without treatment and the number of observations made in the study (i.e. number of animals). To evaluate test sensitivity to detect drug-induced changes in myocardial contractility using the variable LVdP/dtmax, a HESI-supported consortium designed and conducted studies in chronically instrumented, conscious dogs using telemetry. This paper evaluated the inherent variability of the primary endpoint, LVdP/dtmax, over time in individual animals as well as the variability between animals for a given laboratory. An approach is described to evaluate test system variability and thereby test sensitivity which may be used to support the selection of the number of animals for a given study, based on the desired test sensitivity. Methods A double 4 × 4 Latin square study design where eight animals each received a vehicle control and three dose levels of a test compound was conducted at six independent laboratories. LVdP/dtmax was assessed via implanted telemetry systems in Beagle dogs (N = 8) using the same protocol and each of the six laboratories conducted between two and four studies. Vehicle data from each study was used to evaluate the between-animal and within-animal variability in different time averaging windows. Simulations were conducted to evaluate statistical power and type I error for LVdP/dtmax based on the estimated variability and assumed treatment effects in hourly-interval, bi-hourly interval, or drug-specific super interval. Results We observe that the within-animal variability can be reduced by as much as 30% through the use of a larger time averaging window. Laboratory is a significant source of animal-to-animal variability as between-animal variability is laboratory-dependent and is less impacted by the use of different time averaging windows. The statistical power analysis shows

The pivotal role of safety pharmacology in the safety testing of new drugs is now well established, having received a large impetus through the regulatory requirement of this type of study and the appearance of the ICHS7A guidance in 2001 (US FDA, 2001). This has contributed substantially to development of safer medicines and the avoidance of untoward effects in early clinical trials. Many may not be aware that during the negotiations leading to the ICH guidance, a major discussion point was whether safety pharmacology studies should be conducted according to good laboratory practice (GLP) and there were many valid reasons for and against this requirement (Bass, Hombo, Kasai, Kinter, & Valentin, 2015). However, regulatory safety studies are viewed to necessitate GLP and this won the day. Although few would now question the need for GLP compliance for a safety pharmacology “core battery” study, we should still take the time to evaluate how this has impacted safety testing and its quality

This chapter highlights various non-automated classical in vitro techniques used today to evaluate drug effects on cardiac electrophysiology. It then outlines a three-pronged preclinical initiative called the Comprehensive In Vitro Proarrhythmia Assay (CiPA), which consists of understanding the effects of new molecular entities on multiple ion channels (including IKr) using voltage clamp techniques, in silico prediction simulations (proarrhythmic liability) based on the ion channel effects, and an integrated human cellular study to provide confirmatory electrophysiological data (most likely involving human stem cell-derived cardiomyocytes (CMs)). The chapter also discusses extremely valuable technology for safety pharmacologists, different between in vitro and in vivo models that can help to identify drugs with potential negative and positive effects on cardiac contractility and how the CV SP assessment of conventional small molecules differs from the approach taken for biologics. Finally the chapter discusses why safety pharmacologists should consider embracing new approaches