scholarly journals Mechanisms of QT prolongation by buprenorphine cannot be explained by direct hERG channel block

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241362
Author(s):  
Phu N. Tran ◽  
Jiansong Sheng ◽  
Aaron L. Randolph ◽  
Claudia Alvarez Baron ◽  
Nicolas Thiebaud ◽  
...  

Buprenorphine is a μ-opioid receptor (MOR) partial agonist used to manage pain and addiction. QTC prolongation that crosses the 10 msec threshold of regulatory concern was observed at a supratherapeutic dose in two thorough QT studies for the transdermal buprenorphine product BUTRANS®. Because QTC prolongation can be associated with Torsades de Pointes (TdP), a rare but potentially fatal ventricular arrhythmia, these results have led to further investigation of the electrophysiological effects of buprenorphine. Drug-induced QTC prolongation and TdP are most commonly caused by acute inhibition of hERG current (IhERG) that contribute to the repolarizing phase of the ventricular action potentials (APs). Concomitant inhibition of inward late Na+ (INaL) and/or L-type Ca2+ (ICaL) current can offer some protection against proarrhythmia. Therefore, we characterized the effects of buprenorphine and its major metabolite norbuprenorphine on cardiac hERG, Ca2+, and Na+ ion channels, as well as cardiac APs. For comparison, methadone, a MOR agonist associated with QTC prolongation and high TdP risk, and naltrexone and naloxone, two opioid receptor antagonists, were also studied. Whole cell recordings were performed at 37°C on cells stably expressing hERG, CaV1.2, and NaV1.5 proteins. Microelectrode array (MEA) recordings were made on human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). The results showed that buprenorphine, norbuprenorphine, naltrexone, and naloxone had no effect on IhERG, ICaL, INaL, and peak Na+ current (INaP) at clinically relevant concentrations. In contrast, methadone inhibited IhERG, ICaL, and INaL. Experiments on iPSC-CMs showed a lack of effect for buprenorphine, norbuprenorphine, naltrexone, and naloxone, and delayed repolarization for methadone at clinically relevant concentrations. The mechanism of QTC prolongation is opioid moiety-specific. This remains undefined for buprenorphine, while for methadone it involves direct hERG channel block. There is no evidence that buprenorphine use is associated with TdP. Whether this lack of TdP risk can be generalized to other drugs with QTC prolongation not mediated by acute hERG channel block warrants further study.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Francesca Stillitano ◽  
Ioannis Karakikes ◽  
Chi-wai Kong ◽  
Brett Martinelli ◽  
Ronald Li ◽  
...  

Long QT syndrome (LQTS) is characterized by prolonged cardiac repolarization time and increased risk of ventricular arrhythmia. LQTS can be either inherited or induced notably after drugs intake. Mutations in genes encoding cardiac ion channels have been reported to underlie inherited LQTS. In contrast, drug-induced LQTS (diLQTS) most frequently arises from altered function of the hERG channel; the risk of developing diLQTS varies largely between subjects and most people who have life-threatening diLQTS have no known genetic risk factors. We investigated whether the susceptibility to develop diLQTS observed in vivo can be recapitulated in vitro using patient-specific induced pluripotent stem cell (iPSC) technology. We collected skin fibroblasts from ten subjects who developed significant diLQTS after administration of Sotalol and/or Erythromycin. Ten other individuals who displayed no changes in QT interval after administration of the same drugs, were selected. iPSC were generated by retroviral delivery of Oct4, Sox2, Nanog and Klf4 in 17 of the 20 individuals. We report preliminary results obtained from iPSC-derived cardiomyocytes (iPSC-CMs) of two subjects. All experiments were performed in a blinded fashion without knowledge of the associated clinical phenotype. Cardiac differentiation of iPSC resulted in the generation of spontaneously beating embryoid bodies. iPSC-CMs showed positive staining for TNNT2, ACTN2 and Cx43. Gene expression analysis confirmed the expression of NKX2.5, MLC2v, MYH6 and MYH7, and of the relevant KCNH2 gene. The two lines had similar basal electrophysiological properties as assessed by measurements of action potential (AP) by patch-clamp technique and extracellular field potentials (FP) using micro-electrode array (MEA). E4031, a classical HERG blocker, significantly prolonged the FP duration (FPD) in a dose-dependent manner in both lines (EC50: 30.19 and 51.57 respectively). When both Sotalol and Erythromicin were used, FPD was prolonged in one of the two samples in a dose-dependent manner (EC50Sotalol: 100; EC50Erythr: 9.64) while drug response was blunted in the other cell line. This study suggests that patient-specific iPSC can be used to model the functional abnormalities observed in acquired diLQTS.


2019 ◽  
Vol 125 (10) ◽  
Author(s):  
Gary Gintant ◽  
Paul Burridge ◽  
Lior Gepstein ◽  
Sian Harding ◽  
Todd Herron ◽  
...  

It is now well recognized that many lifesaving oncology drugs may adversely affect the heart and cardiovascular system, including causing irreversible cardiac injury that can result in reduced quality of life. These effects, which may manifest in the short term or long term, are mechanistically not well understood. Research is hampered by the reliance on whole-animal models of cardiotoxicity that may fail to reflect the fundamental biology or cardiotoxic responses of the human myocardium. The emergence of human induced pluripotent stem cell–derived cardiomyocytes as an in vitro research tool holds great promise for understanding drug-induced cardiotoxicity of oncological drugs that may manifest as contractile and electrophysiological dysfunction, as well as structural abnormalities, making it possible to deliver novel drugs free from cardiac liabilities and guide personalized therapy. This article briefly reviews the challenges of cardio-oncology, the strengths and limitations of using human induced pluripotent stem cell–derived cardiomyocytes to represent clinical findings in the nonclinical research space, and future directions for their further use.


2020 ◽  
Vol 176 (1) ◽  
pp. 103-123 ◽  
Author(s):  
Umber Saleem ◽  
Berend J van Meer ◽  
Puspita A Katili ◽  
Nurul A N Mohd Yusof ◽  
Ingra Mannhardt ◽  
...  

Abstract Animal models are 78% accurate in determining whether drugs will alter contractility of the human heart. To evaluate the suitability of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for predictive safety pharmacology, we quantified changes in contractility, voltage, and/or Ca2+ handling in 2D monolayers or 3D engineered heart tissues (EHTs). Protocols were unified via a drug training set, allowing subsequent blinded multicenter evaluation of drugs with known positive, negative, or neutral inotropic effects. Accuracy ranged from 44% to 85% across the platform-cell configurations, indicating the need to refine test conditions. This was achieved by adopting approaches to reduce signal-to-noise ratio, reduce spontaneous beat rate to ≤ 1 Hz or enable chronic testing, improving accuracy to 85% for monolayers and 93% for EHTs. Contraction amplitude was a good predictor of negative inotropes across all the platform-cell configurations and of positive inotropes in the 3D EHTs. Although contraction- and relaxation-time provided confirmatory readouts forpositive inotropes in 3D EHTs, these parameters typically served as the primary source of predictivity in 2D. The reliance of these “secondary” parameters to inotropy in the 2D systems was not automatically intuitive and may be a quirk of hiPSC-CMs, hence require adaptations in interpreting the data from this model system. Of the platform-cell configurations, responses in EHTs aligned most closely to the free therapeutic plasma concentration. This study adds to the notion that hiPSC-CMs could add value to drug safety evaluation.


2012 ◽  
Vol 17 (5) ◽  
pp. 683-691 ◽  
Author(s):  
Tadahiro Shinozawa ◽  
Hatsue Furukawa ◽  
Eimei Sato ◽  
Kenji Takami

Cardiomyocytes derived from embryonic stem cells (ES-CMs) and induced pluripotent stem cells (iPS-CMs) are useful for toxicity and pharmacology screening. In the present study, we found that cardiomyocyte-rich beating cell clusters (CCs) emerged from murine embryonic stem cell (mESC)–derived beating EBs and from human-induced pluripotent stem cell (hiPSC)–derived beating EBs dissociated by gentle pipetting with a thin glass pipette. The percentage of cardiac troponin T (cTnT)–positive cells in the beating CCs obtained from mESC-derived and hiPSC-derived beating EBs was higher (81.5% and 91.6%, respectively) than in beating-undissociated EBs (13.7% and 67.1%, respectively). For mESCs, the yield of cTnT-positive cells from beating CCs was estimated to be 1.6 times higher than that of beating EBs. The bromodeoxyuridine labeling index of mouse ES-CMs and human iPS-CMs in beating CCs was 1.5- and 3.2-fold, respectively, greater than those in beating EBs. To investigate the utility of the cells in toxicity assessment, we showed that doxorubicin, a cardiotoxic drug, induced myofilament disruption in cardiomyocytes isolated by this method. This simple method enables preparation of mouse ES-CMs and human iPS-CMs with better proliferative activity than beating EBs not dissociated by pipetting, and the cardiomyocytes are useful for drug-induced myocardial toxicity testing.


2020 ◽  
pp. 247255522095320
Author(s):  
Shuyun Bai ◽  
Junjie Pei ◽  
Kan Chen ◽  
Ya Zhao ◽  
Henghua Cao ◽  
...  

Human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) have been widely used for the assessment of drug proarrhythmic potential through multielectrode array (MEA). HiPSC-CM cultures beat spontaneously with a wide range of frequencies, however, which could affect drug-induced changes in repolarization. Pacing hiPSC-CMs at a physiological heart rate more closely resembles the state of in vivo ventricular myocytes and permits the standardization of test conditions to improve consistency. In this study, we systematically investigated the time window of stable ion currents in high-purity hiPSC-derived ventricular cardiomyocytes (hiPSC-vCMs) and confirmed that these cells could be used to correctly predict the proarrhythmic risk of Comprehensive In Vitro Proarrhythmia Assay (CiPA) reference compounds. To evaluate drug proarrhythmic potentials at a physiological beating rate, we used a MEA to electrically pace hiPSC-vCMs, and we recorded regular field potential waveforms in hiPSC-vCMs treated with DMSO and 10 CiPA reference drugs. Prolongation of field potential duration was detected in cells after exposure to high- and intermediate-risk drugs; in addition, drug-induced arrhythmia-like events were observed. The results of this study provide a simple and feasible method to investigate drug proarrhythmic potentials in hiPSC-CMs at a physiological beating rate.


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