Cardiac safety pharmacology: from human ether-a-gogo related gene channel block towards induced pluripotent stem cell based disease models

INTRODUCTION: The field of cardiac safety pharmacology has been experiencing exciting changes over the recent years. Drug induced arrhythmia of the torsade des pointes types has been the reason for the denial of approval of novel drug candidates. The aim of cardiac safety pharmacology is to detect undesirable pharmacodynamic drug effects within and above the therapeutic range. A special focus is on the identification of potential arrhythmogenic effects within the drug discovery chain. AREAS COVERED: Here, the authors discuss the relevance of induced pluripotent stem (iPS) cell derived cardiomyocytes for safety pharmacology. The technology of obtaining functional cardiomyocytes from somatic cells of healthy donors and patients with inherited diseases is the basis for diverse disease models in multi-level safety pharmacology screening. The reader will gain an overview of stem cell based technologies in cardiac safety pharmacology in cardiac and disease modeling by iPS cell derived cardiomyocytes from patients with an inherited cardiac syndrome. EXPERT OPINION: iPS cell derived cardiomyocytes - especially from patients with increased risk of cardiac arrhythmia - are on the verge of offering new options for drug testing. More reliable assays can be expected to predict the arrhythmogenic risk of drug candidates in humans. However, this technology is still new and extensive validation studies are due.     

Disease modeling and drug screening for neurological diseases using human induced pluripotent stem cells

With the general decline of pharmaceutical research productivity, there are concerns that many components of the drug discovery process need to be redesigned and optimized. For example, the human immortalized cell lines or animal primary cells commonly used in traditional drug screening may not faithfully recapitulate the pathological mechanisms of human diseases, leading to biases in assays, targets, or compounds that do not effectively address disease mechanisms. Recent advances in stem cell research, especially in the development of induced pluripotent stem cell (iPSC) technology, provide a new paradigm for drug screening by permitting the use of human cells with the same genetic makeup as the patients without the typical quantity constraints associated with patient primary cells. In this article, we will review the progress made to date on cellular disease models using human stem cells, with a focus on patient-specific iPSCs for neurological diseases. We will discuss the key challenges and the factors that associated with the success of using stem cell models for drug discovery through examples from monogenic diseases, diseases with various known genetic components, and complex diseases caused by a combination of genetic, environmental and other factors.     

Application of human pluripotent stem cells and pluripotent stem cell-derived cellular models for assessing drug toxicity

Introduction: Human pluripotent stem cells (hPSCs) are capable of differentiating into all types of cells in the body and so provide suitable toxicology screening systems even for hard-to-obtain human tissues. Since hPSCs can also be generated from differentiated cells and current gene editing technologies allow targeted genome modifications, hPSCs can be applied for drug toxicity screening both in normal and disease-specific models. Targeted hPSC differentiation is still a challenge but cardiac, neuronal or liver cells, and complex cellular models are already available for practical applications.

Areas covered: The authors review new gene-editing and cell-biology technologies to generate sensitive toxicity screening systems based on hPSCs. Then the authors present the use of undifferentiated hPSCs for examining embryonic toxicity and discuss drug screening possibilities in hPSC-derived models. The authors focus on the application of human cardiomyocytes, hepatocytes, and neural cultures in toxicity testing, and discuss the recent possibilities for drug screening in a ‘body-on-a-chip’ model system.

Expert opinion: hPSCs and their genetically engineered derivatives provide new possibilities to investigate drug toxicity in human tissues. The key issues in this regard are still the selection and generation of proper model systems, and the interpretation of the results in understanding in vivo drug effects.     

Human embryonic stem cell-derived cardiomyocytes: drug discovery and safety pharmacology

Human embryonic stem cells (hESCs) can provide potentially unlimited quantities of a wide range of human cell types that can be used in drug discovery and development, basic research and regenerative medicine. In this review, the authors describe the differentiation of hESCs into cardiomyocytes and outline the properties of hESC-derived cardiomyocytes (hESC-CMs), including their cardiac-type action potentials and contractile characteristics. In vitro cellular assays using hESC-CMs, which can be genetically engineered to create target-specific reporters as well as human disease models, will have applications at multiple stages of the drug discovery process. Furthermore, cardiac safety pharmacology assays evaluating the risk of proarrhythmic side effects associated with QT prolongation may be enhanced in their predictive value with the use of hESC-CMs.     

利用诱导多能干细胞构建流产毒性药物的体外筛查模型

妊娠期用药不可避免,如何帮助孕妇合理用药以减少自发流产、早产和低体重儿的发生,对于医务工作者至关重要.本研究建立了药物流产毒性的检测模型,可筛除疑似流产的药物,避免用药不当导致的孕妇流产.通过三维悬浮培养诱导多能干细胞(induced pluripotent stem cells,iPSCs)的方式,诱导其形成拟胚体(...     

用人类诱导多能干细胞来源的心肌细胞快速检测中药毒性的方法

目的建立一种利用人类诱导多能干细胞来源的心肌细胞(hi PSC-CM)快速并且有效筛选中药复方毒性的方法。方法用hi PSC-CM检测了29种市场上常用的中药复方,通过细胞的形态和心肌跳动速度的变化,检测中药复方的毒性。结果实验发现包括云南白药胶囊等在内的19种中药复方对hi PSC-CM的跳动有明显影响,而包括痰咳净片等在内的10种中药复方对hi PSC-CM无明显影响。结论药物效果与已报道的药物不良反应一致,利用hi PSC-CM是一种快速且有效筛选中药复方毒性的方法。     

Proarrhythmia risk prediction using human induced pluripotent stem cell-derived cardiomyocytes

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are expected to become a useful tool for proarrhythmia risk prediction in the non-clinical drug development phase. Several features including electrophysiological properties, ion channel expression profile and drug responses were investigated using commercially available hiPSC-CMs, such as iCell-CMs and Cor.4U-CMs. Although drug-induced arrhythmia has been extensively examined by microelectrode array (MEA) assays in iCell-CMs, it has not been fully understood an availability of Cor.4U-CMs for proarrhythmia risk. Here, we evaluated the predictivity of proarrhythmia risk using Cor.4U-CMs. MEA assay revealed linear regression between inter-spike interval and field potential duration (FPD). The hERG inhibitor E?4031 induced reverse-use dependent FPD prolongation. We next evaluated the proarrhythmia risk prediction by a two-dimensional map, which we have previously proposed. We determined the relative torsade de pointes risk score, based on the extent of FPD with Fridericia's correction (FPDcF) change and early afterdepolarization occurrence, and calculated the margins normalized to free effective therapeutic plasma concentrations. The drugs were classified into three risk groups using the two-dimensional map. This risk-categorization system showed high concordance with the torsadogenic information obtained by a public database CredibleMeds. Taken together, these results indicate that Cor.4U-CMs can be used for drug-induced proarrhythmia risk prediction.     

Availability of human induced pluripotent stem cell-derived cardiomyocytes in assessment of drug potential for QT prolongation

Field potential duration (FPD) in human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs), which can express QT interval in an electrocardiogram, is reported to be a useful tool to predict K⁺ channel and Ca^2 + channel blocker effects on QT interval. However, there is no report showing that this technique can be used to predict multichannel blocker potential for QT prolongation. The aim of this study is to show that FPD from MEA (Multielectrode array) of hiPS-CMs can detect QT prolongation induced by multichannel blockers.     

Drug metabolizing enzyme and transporter protein profiles of hepatocytes derived from human embryonic and induced pluripotent stem cells

Human embryonic and induced pluripotent stem cell-derived hepatocytes (hESC-Hep and hiPSC-Hep) have the potential to provide relevant human in vitro model systems for toxicity testing and drug discovery studies. In this study, the expression and function of important drug metabolizing cytochrome P450 (CYP) enzymes and transporter proteins in hESC-Hep and hiPSC-Hep were compared to cryopreserved human primary hepatocytes (hphep) and HepG2 cells. Overall, CYP activities in hESC-Hep and hiPSC-Hep were much lower than in hphep cultured for 4 h, but CYP1A and 3A activities were comparable to levels in hphep cultured for 48 h (CYP1A: 35% and 26% of 48 h hphep, respectively; CYP3A: 80% and 440% of 48 h hphep, respectively). Importantly, in hESC-Hep and hiPSC-Hep, CYP activities were stable or increasing for at least one week in culture which was in contrast to the rapid loss of CYP activities in cultured hphep between 4 and 48 h after plating. With regard to transporters, in hESC-Hep and hiPSC-Hep, pronounced NTCP activity (17% and 29% of 4 h hphep, respectively) and moderate BSEP activity (6% and 8% of 4 h hphep, respectively) were observed. Analyses of mRNA expression and immunocytochemistry supported the observed CYP and transporter activities and showed expression of additional CYPs and transporters. In conclusion, the stable expression and function of CYPs and transporters in hESC-Hep and hiPSC-Hep for at least one week opens up the possibility to reproducibly perform long term and extensive studies, e.g. chronic toxicity testing, in a stem cell-derived hepatic system.     

CSAHi study: Validation of multi-electrode array systems (MEA60/2100) for prediction of drug-induced proarrhythmia using human iPS cell-derived cardiomyocytes -assessment of inter-facility and cells lot-to-lot-variability-

In vitro screening of hERG channels are recommended under ICH S7B guidelines to predict drug-induced QT prolongation and Torsade de Pointes (TdP), whereas proarrhythmia is known to be evoked by blockage of other ion channels involved in cardiac contraction and compensation mechanisms. A consortium for drug safety assessment using human iPS cells-derived cardiomyocytes (hiPS-CMs), CSAHi, has been organized to establish a novel in vitro test system that would enable better prediction of drug-induced proarrhythmia and QT prolongation. Here we report the inter-facility and cells lot-to-lot variability evaluated with FPDc (corrected field potential duration), FPDc₁₀ (10% FPDc change concentration), beat rate and incidence of arrhythmia-like waveform or arrest on hiPS-CMs in a multi-electrode array system.Arrhythmia-like waveforms were evident for all test compounds, other than chromanol 293B, that evoked FPDc prolongation in this system and are reported to induce TdP in clinical practice. There was no apparent cells lot-to-lot variability, while inter-facility variabilities were limited within ranges from 3.9- to 20-folds for FPDc₁₀ and about 10-folds for the minimum concentration inducing arrhythmia-like waveform or arrests.In conclusion, the new assay model reported here would enable accurate prediction of a drug potential for proarrhythmia.