Ineffective of lopinavir/ritonavir and chloroquine for a COVID-19 treatment: A perspective of physiologically-based pharmacokinetic and pharmacodynamic modelling (preprint)

Ineffective selection of therapeutic drugs during an urgent situation leads to failure for COVID-19 treatment in large clinical trials, resulting in wasting time and cost. We aimed to demonstrate the utility of physiologically-based pharmacokinetic (PBPK)/pharmacodynamic (PD) modeling to support the withdrawal of chloroquine and ritonavir-boosted lopinavir (LPV/r) for COVID-19 treatment. The developed whole-body PBPK models were validated against clinical data. Model validation was performed using acceptable methods. The inhibitory effect was calculated to demonstrate drug efficacy. Various regimens of chloroquine and LPV/r for COVID-19 treatment in different clinical trials were used for a simulation. The risk of cardiotoxicity following high dose chloroquine administration was assessed. The effect of lung pH on drug concentrations in epithelial lining fluid (ELF) following a high dose of chloroquine and LPV/r was evaluated. The whole-body PBPK models were successfully developed (AAFEs of 1.2-fold). The inhibitory effect (%E) of chloroquine following high dose regimens in both ELF and bronchial epithelial cells (BEC) were lower than 2 and 1%, respectively. The corresponding values for the high dose of LPV/r were 40 and 2%, respectively. The risk of prolonged QTc in the population was higher than 20%. In addition, the %E of chloroquine was increased to 76% at pH 5.6 and decreased to 0.13% at pH 7.5. The change in pH in ELF had no influence on LPV/r concentrations. PBPK/PD modelling supports the withdrawal of chloroquine and LPV/r for COVID-19 treatment as an effective tool for the selection of therapeutic drug regimens in urgent situation.

Innate Immune Activation and Mitochondrial ROS Invoke Persistent Cardiac Conduction System Dysfunction after COVID-19 (preprint)

BackgroundCardiac risk rises during acute SARS-CoV-2 infection and in long COVID syndrome in humans, but the mechanisms behind COVID-19-linked arrhythmias are unknown. This study explores the acute and long term effects of SARS-CoV-2 on the cardiac conduction system (CCS) in a hamster model of COVID-19. MethodsRadiotelemetry in conscious animals was used to non-invasively record electrocardiograms and subpleural pressures after intranasal SARS-CoV-2 infection. Cardiac cytokines, interferon-stimulated gene expression, and macrophage infiltration of the CCS, were assessed at 4 days and 4 weeks post-infection. A double-stranded RNA mimetic, polyinosinic:polycytidylic acid (PIC), was used in vivo and in vitro to activate viral pattern recognition receptors in the absence of SARS-CoV-2 infection. ResultsCOVID-19 induced pronounced tachypnea and severe cardiac conduction system (CCS) dysfunction, spanning from bradycardia to persistent atrioventricular block, although no viral protein expression was detected in the heart. Arrhythmias developed rapidly, partially reversed, and then redeveloped after the pulmonary infection was resolved, indicating persistent CCS injury. Increased cardiac cytokines, interferon-stimulated gene expression, and macrophage remodeling in the CCS accompanied the electrophysiological abnormalities. Interestingly, the arrhythmia phenotype was reproduced by cardiac injection of PIC in the absence of virus, indicating that innate immune activation was sufficient to drive the response. PIC also strongly induced cytokine secretion and robust interferon signaling in hearts, human iPSC-derived cardiomyocytes (hiPSC-CMs), and engineered heart tissues, accompanied by alterations in electrical and Ca2+ handling properties. Importantly, the pulmonary and cardiac effects of COVID-19 were blunted by in vivo inhibition of JAK/STAT signaling or by a mitochondrially-targeted antioxidant. ConclusionsThe findings indicate that long term dysfunction and immune cell remodeling of the CCS is induced by COVID-19, arising indirectly from oxidative stress and excessive activation of cardiac innate immune responses during infection, with implications for long COVID Syndrome.

Mitigating neutrophil trafficking and cardiotoxicity with DS-IkL in a microphysiological system of a cytokine storm.

A feature of severe COVID-19 is the onset of an acute and intense systemic inflammatory response referred to as the "cytokine storm". The cytokine storm is characterized by high serum levels of inflammatory cytokines and the subsequent transport of inflammatory cells to damaging levels in vital organs (e.g., myocarditis). Immune trafficking and its effect on underlying tissues (e.g., myocardium) are challenging to observe at a high spatial and temporal resolution in mouse models. In this study, we created a vascularized organ-on-a-chip system to mimic cytokine storm-like conditions and tested the effectiveness of a novel multivalent selectin-targeting carbohydrate conjugate (composed of DS - dermatan sulfate and IkL - a selectin-binding peptide, termed DS-IkL) in blocking infiltration of polymorphonuclear leukocytes (PMN). Our data shows that cytokine storm-like conditions induce endothelial cells to produce additional inflammatory cytokines and facilitate infiltration of PMNs into tissue. Treatment of tissues with DS-IkL (60 µM) reduced PMN accumulation in the tissue by >50%. We then created cytokine storm-like conditions in a vascularized cardiac tissue-chip and found that PMN infiltration increases the spontaneous beating rate of the cardiac tissue, and this effect is eliminated by treatment with DS-IkL (60 µM). In summary, we demonstrate the utility of an organ-on-a-chip platform to mimic COVID-19 related cytokine storm and that blocking leukocyte infiltration with DS-IkL could be a viable strategy to mitigate associated cardiac complications.

Cardiotoxicity of chloroquine and hydroxychloroquine through mitochondrial pathway.

BACKGROUND: Medical therapies can cause cardiotoxicity. Chloroquine (QC) and hydroxychloroquine (HQC) are drugs used in the treatment of malaria and skin and rheumatic disorders. These drugs were considered to help treatment of coronavirus disease (COVID-19) in 2019. Despite the low cost and availability of QC and HQC, reports indicate that this class of drugs can cause cardiotoxicity. The mechanism of this event is not well known, but evidence shows that QC and HQC can cause cardiotoxicity by affecting mitochondria and lysosomes. METHODS: Therefore, our study was designed to investigate the effects of QC and HQC on heart mitochondria. In order to achieve this aim, mitochondrial function, reactive oxygen species (ROS) level, mitochondrial membrane disruption, and cytochrome c release in heart mitochondria were evaluated. Statistical significance was determined using the one-way and two-way analysis of variance (ANOVA) followed by post hoc Tukey to evaluate mitochondrial succinate dehydrogenase (SDH) activity and cytochrome c release, and Bonferroni test to evaluate the ROS level, mitochondrial membrane potential (MMP) collapse, and mitochondrial swelling. RESULTS: Based on ANOVA analysis (one-way), the results of mitochondrial SDH activity showed that the IC50 concentration for CQ is 20 µM and for HCQ is 50 µM. Based on two-way ANOVA analysis, the highest effect of CQ and HCQ on the generation of ROS, collapse in the MMP, and mitochondrial swelling were observed at 40 µM and 100 µM concentrations, respectively (p < 0.05). Also, the highest effect of these two drugs has been observed in 60 min (p < 0.05). The statistical results showed that compared to CQ, HCQ is able to cause the release of cytochrome c from mitochondria in all applied concentrations (p < 0.05). CONCLUSIONS: The results suggest that QC and HQC can cause cardiotoxicity which can lead to heart disorders through oxidative stress and disfunction of heart mitochondria.

Prospective QTc interval monitoring avoids cardiac toxicity of hydroxychloroquine and azithromycin in critically ill SARS-CoV-2 patients: a cohort study (preprint)

Purpose During the first wave of the SARS-Cov2 pandemic, the use of hydroxychloroquine and azithromycin raised safety concerns in terms of arrhythmias related to QT segment prolongation. The aim of this observational, prospective, single-center study was to describe cardiovascular events in critically ill patients who were mechanically ventilated for SARS-Cov2 pneumonia. Methods Patients included were prospectively monitored for QTc segment prolongation when treated with the association of hydroxychloroquine alone or in combination with azithromycin for Covid-19 pneumonia and treatment had to be stopped before QTc ≤ 500ms. Results 23 patients were prospectively included. Treatment had to be interrupted in 43.5% of patients and more often in the combination group. None of the patients displayed torsade de pointes or sudden cardiac arrest. Forty percent of patients in the combination group experienced atrial fibrillation. Cardiac Troponin I was elevated in 70% of all patients without electric signs of ischemia. Conclusion The association of hydroxychloroquine and azithromycin for treatment of Covid-19 pneumonia mandates the need for prospective evaluation of QTc especially in the presence of biological myocardial injury. The Institutional Review Board waived the need for consent to use prospectively collected clinical data and the study was appointed the serial number 2020-214.

A Systematic Review of Nonclinical Studies on the Effect of Curcumin in Chemotherapy- induced Cardiotoxicity.

BACKGROUND: Various anticancer drugs are effective therapeutic agents for cancer treatment; however, they cause severe toxicity in body organs. Cardiotoxicity is one of the most critical side effects of these drugs. Based on various findings, turmeric extract has positive effects on cardiac cells. OBJECTIVE: This study aims to evaluate how curcumin, as the main component of turmeric, may affect chemotherapy- induced cardiotoxicity. METHODS: A database search was performed up to April 2021 using "curcumin OR turmeric OR Curcuma longa" and "chemotherapy-induced cardiac disease", including their equivalents and similar terms. After screening the total articles obtained from the electronic databases, 25 relevant articles were included in this systematic review. RESULTS: The studies demonstrate lower body weight and increased mortality rates due to doxorubicin administration. Besides, cancer therapeutic agents induced various morphological and biochemical abnormalities compared to the non-treated groups. Based on most of the obtained results, curcumin at nontoxic doses can protect the cardiac cells mainly through modulating antioxidant capacity, regulation of cell death, and antiinflammatory effects. Nevertheless, according to a minority of findings, curcumin increases the susceptibility of the rat cardiomyoblast cell line (H9C2) to apoptosis triggered by doxorubicin. CONCLUSION: According to most nonclinical studies, curcumin could potentially have cardioprotective effects against chemotherapy-induced cardiotoxicity. However, based on limited, contradictory findings demonstrating the function of curcumin in potentiating doxorubicin-induced cardiotoxicity, well-designed studies are needed to evaluate the safety and effectiveness of treatment with new formulations of this compound during cancer therapy.

Review of Hydroxychloroquine Cardiotoxicity: Lessons From the COVID-19 Pandemic.

PURPOSE OF REVIEW: The coronavirus disease 2019 (COVID-19) pandemic has popularized the usage of hydroxychloroquine and chloroquine (HCQ/CQ) as treatments for COVID-19. Previously used as anti-malarial and now commonly used in rheumatologic conditions, preliminary in vitro studies have demonstrated these medications also have anti-viral properties. Retinopathy and neuromyopathy are well recognized complications of using these treatments; however, cardiotoxicity is under-recognized. This review will discuss the implications and cardiotoxicity of HCQ/CQ, their mechanisms of action, and their utility in COVID-19. RECENT FINDINGS: Early clinical trials demonstrated a modest benefit of HCQ in COVID-19, causing a push for the usage of it. However, further large multi-center randomized control centers, demonstrated no benefit, and even a trend towards worse outcomes. The predominant cardiac complication observed with HCQ in COVID-19 was cardiac arrhythmias and prolonging of the QT interval. However, with chronic usage of HCQ/CQ, the development of heart failure (HF) and cardiomyopathy (CM) can occur. Although, most adverse cardiac events related to HCQ/CQ usage in COVID-19 were secondary to conduction disorders given the short duration of treatment, HCQ/CQ can cause CM and HF, with chronic usage. Given the insufficient evidence, HCQ/CQ usage in COVID-19 is not routinely recommended, especially with novel therapies now being developed and used. Additionally, usage of HCQ/CQ should prompt initial cardiac evaluation with ECG, and yearly monitoring, with consideration for advanced imaging if clinically warranted. The diagnosis of HCQ/CQ cardiomyopathy is important, as prompt cessation can allow for recovery when these changes are still reversible.

Investigating and Resolving Cardiotoxicity Induced by COVID-19 Treatments using Human Pluripotent Stem Cell-Derived Cardiomyocytes and Engineered Heart Tissues.

Coronavirus disease 2019 continues to spread worldwide. Given the urgent need for effective treatments, many clinical trials are ongoing through repurposing approved drugs. However, clinical data regarding the cardiotoxicity of these drugs are limited. Human pluripotent stem cell-derived cardiomyocytes (hCMs) represent a powerful tool for assessing drug-induced cardiotoxicity. Here, by using hCMs, it is demonstrated that four antiviral drugs, namely, apilimod, remdesivir, ritonavir, and lopinavir, exhibit cardiotoxicity in terms of inducing cell death, sarcomere disarray, and dysregulation of calcium handling and contraction, at clinically relevant concentrations. Human engineered heart tissue (hEHT) model is used to further evaluate the cardiotoxic effects of these drugs and it is found that they weaken hEHT contractile function. RNA-seq analysis reveals that the expression of genes that regulate cardiomyocyte function, such as sarcomere organization (TNNT2, MYH6) and ion homeostasis (ATP2A2, HCN4), is significantly altered after drug treatments. Using high-throughput screening of approved drugs, it is found that ceftiofur hydrochloride, astaxanthin, and quetiapine fumarate can ameliorate the cardiotoxicity of remdesivir, with astaxanthin being the most prominent one. These results warrant caution and careful monitoring when prescribing these therapies in patients and provide drug candidates to limit remdesivir-induced cardiotoxicity.

Role of cardiac MRI in the diagnosis of immune checkpoint inhibitor-associated myocarditis.

Immune checkpoint inhibitor (ICI)-induced cardiotoxicity is a rare immune-related adverse event (irAE) characterized by a high mortality rate. From a pathological point of view, this condition can result from a series of causes, including binding of ICIs to target molecules on nonlymphocytic cells, cross-reaction of T lymphocytes against tumor antigens with off-target tissues, generation of autoantibodies and production of proinflammatory cytokines. The diagnosis of ICI-induced cardiotoxicity can be challenging, and cardiac magnetic resonance (CMR) represents the diagnostic tool of choice in clinically stable patients with suspected myocarditis. CMR is gaining a central role in diagnosis and monitoring of cardiovascular damage in cancer patients, and it is entering international cardiology and oncology guidelines. In this narrative review, we summarized the clinical aspects of ICI-associated myocarditis, highlighting its radiological aspects and proposing a novel algorithm for the use of CMR.

The new HFA/ICOS risk assessment tool to identify patients with chronic myeloid leukaemia at high risk of cardiotoxicity.

AIMS: Tyrosine kinase inhibitors (TKIs) used to treat chronic myeloid leukaemia (CML) can cause cardiovascular adverse events. So far, the Systematic Coronary Risk Evaluation (SCORE) charts of the European Society of Cardiology (ESC) have been used to identify cancer patients at increased cardiovascular risk. The primary aim of our study was to evaluate the usefulness of the new cardiovascular risk assessment model proposed by the Cardio-Oncology Study Group of the Heart Failure Association (HFA) of the ESC in collaboration with the International Cardio-Oncology Society (ICOS) to stratify the cardiovascular risk in CML patients, compared with SCORE risk charts. The secondary aim was to establish the incidence of adverse arterial events (AEs) in patients with CML treated with TKIs and the influence of preventive treatment with aspirin. METHODS AND RESULTS: A retrospective single-centre observational study was carried out on 58 patients (32 men and 26 women; mean age ± SD: 59 ± 15 years) with CML treated with TKIs for a median period of 43 ± 31 months. Cardiological evaluation was performed and cardiovascular risk was estimated with SCORE risk charts and with the new risk assessment tool proposed by HFA/ICOS. AEs were recorded. According to SCORE charts and the new HFA/ICOS risk stratification tool, respectively, 46% (Group A1) and 60% (Group A2) of patients were at high-very high risk, and 54% (Group B1) and 40% (Group B2) at low-moderate risk. AEs were significantly more frequent in Group A1 than Group B1 (P value < 0.01) when considered overall; they were significantly more frequent in Group A2 than Group B2 either overall or considered individually. HFA/ICOS risk stratification tool was significantly more sensitive than SCORE (P < 0.01) in identifying patients at higher risk of cardiovascular toxicity. In addition, we did not find AEs in patients pretreated with aspirin. CONCLUSIONS: The new HFA/ICOS risk stratification model allows a more tailored cardiovascular risk stratification in patients with CML and it is more sensitive than SCORE charts.

Protective Effects of Meldonium in Experimental Models of Cardiovascular Complications with a Potential Application in COVID-19.

Right ventricular (RV) and left ventricular (LV) dysfunction is common in a significant number of hospitalized coronavirus disease 2019 (COVID-19) patients. This study was conducted to assess whether the improved mitochondrial bioenergetics by cardiometabolic drug meldonium can attenuate the development of ventricular dysfunction in experimental RV and LV dysfunction models, which resemble ventricular dysfunction in COVID-19 patients. Effects of meldonium were assessed in rats with pulmonary hypertension-induced RV failure and in mice with inflammation-induced LV dysfunction. Rats with RV failure showed decreased RV fractional area change (RVFAC) and hypertrophy. Treatment with meldonium attenuated the development of RV hypertrophy and increased RVFAC by 50%. Mice with inflammation-induced LV dysfunction had decreased LV ejection fraction (LVEF) by 30%. Treatment with meldonium prevented the decrease in LVEF. A decrease in the mitochondrial fatty acid oxidation with a concomitant increase in pyruvate metabolism was noted in the cardiac fibers of the rats and mice with RV and LV failure, respectively. Meldonium treatment in both models restored mitochondrial bioenergetics. The results show that meldonium treatment prevents the development of RV and LV systolic dysfunction by enhancing mitochondrial function in experimental models of ventricular dysfunction that resembles cardiovascular complications in COVID-19 patients.

Interleukin-1 blocking agents as promising strategy for prevention of anticancer drug-induced cardiotoxicities: possible implications in cancer patients with COVID-19.

Cytokines in cardiac tissue plays a key role in progression of cardiometabolic diseases and cardiotoxicity induced by several anticancer drugs. Interleukin-1ß is one on the most studied regulator of cancer progression, survival and resistance to anticancer treatments. Recent findings indicate that interleukin1-ß exacerbates myocardial damages in cancer patients treated with chemotherapies and immune check-point inhibitors. Interleukin1-ß blocking agent canakinumab reduces major adverse cardiovascular events and cardiovascular death in recent cardiovascular trials. We focalized on the main biological functions of interleukin1-ß in cancer and cardiovascular diseases, summarizing the main clinical evidence available to date in literature. Especially in the era of SARS-CoV-2 infection, associated to coagulopathies, myocarditis and heart failure, cancer patients have an increased risk of cardiovascular complications compared to general population, therefore, the pharmacological inhibition of interleukin1-ß should be discussed and considered.

American College of Rheumatology White Paper on Antimalarial Cardiac Toxicity.

Hydroxychloroquine (HCQ) and chloroquine (CQ) are well-established medications used in treating systemic lupus erythematosus and rheumatoid arthritis, as well as skin conditions such as cutaneous lupus erythematosus. In rare cases, arrhythmias and conduction system abnormalities, as well as cardiomyopathy, have been reported in association with HCQ/CQ use. Recently, however, the corrected QT interval (QTc)-prolonging potential of these medications, and risk of torsade de pointes (TdP) in particular, have been highlighted in the setting of their experimental use for COVID-19 infection. This report was undertaken to summarize the current understanding of HCQ/CQ cardiac toxicity, describe QTc prolongation and TdP risks, and discuss areas of priority for future research. A working group of experts across rheumatology, cardiology, and dermatology performed a nonsystematic literature review and offered a consensus-based expert opinion. Current data clearly indicate that HCQ and CQ are invaluable medications in the management of rheumatic and dermatologic diseases, but they are associated with QTc prolongation by directly affecting cardiac repolarization. Prescribing clinicians should be cognizant of this small effect, especially in patients taking additional medications that prolong the QTc interval. Long-term use of HCQ/CQ may lead to a cardiomyopathy associated with arrhythmias and heart failure. Risk and benefit assessment should be considered prior to initiation of any medication, and both initial and ongoing risk-benefit assessments are important with regard to prescription of HCQ/CQ. While cardiac toxicity related to HCQ/CQ treatment of rheumatic diseases is rarely reported, it can be fatal. Awareness of the potential adverse cardiac effects of HCQ and CQ can increase the safe use of these medications. There is a clear need for additional research to allow better understanding of the cardiovascular risk and safety profile of these therapies used in the management of rheumatic and cutaneous diseases.

The cardiovascular effects of amodiaquine and structurally related antimalarials: An individual patient data meta-analysis.

BACKGROUND: Amodiaquine is a 4-aminoquinoline antimalarial similar to chloroquine that is used extensively for the treatment and prevention of malaria. Data on the cardiovascular effects of amodiaquine are scarce, although transient effects on cardiac electrophysiology (electrocardiographic QT interval prolongation and sinus bradycardia) have been observed. We conducted an individual patient data meta-analysis to characterise the cardiovascular effects of amodiaquine and thereby support development of risk minimisation measures to improve the safety of this important antimalarial. METHODS AND FINDINGS: Studies of amodiaquine for the treatment or prevention of malaria were identified from a systematic review. Heart rates and QT intervals with study-specific heart rate correction (QTcS) were compared within studies and individual patient data pooled for multivariable linear mixed effects regression. The meta-analysis included 2,681 patients from 4 randomised controlled trials evaluating artemisinin-based combination therapies (ACTs) containing amodiaquine (n = 725), lumefantrine (n = 499), piperaquine (n = 716), and pyronaridine (n = 566), as well as monotherapy with chloroquine (n = 175) for uncomplicated malaria. Amodiaquine prolonged QTcS (mean = 16.9 ms, 95% CI: 15.0 to 18.8) less than chloroquine (21.9 ms, 18.3 to 25.6, p = 0.0069) and piperaquine (19.2 ms, 15.8 to 20.5, p = 0.0495), but more than lumefantrine (5.6 ms, 2.9 to 8.2, p < 0.001) and pyronaridine (-1.2 ms, -3.6 to +1.3, p < 0.001). In individuals aged ≥12 years, amodiaquine reduced heart rate (mean reduction = 15.2 beats per minute [bpm], 95% CI: 13.4 to 17.0) more than piperaquine (10.5 bpm, 7.7 to 13.3, p = 0.0013), lumefantrine (9.3 bpm, 6.4 to 12.2, p < 0.001), pyronaridine (6.6 bpm, 4.0 to 9.3, p < 0.001), and chloroquine (5.9 bpm, 3.2 to 8.5, p < 0.001) and was associated with a higher risk of potentially symptomatic sinus bradycardia (≤50 bpm) than lumefantrine (risk difference: 14.8%, 95% CI: 5.4 to 24.3, p = 0.0021) and chloroquine (risk difference: 8.0%, 95% CI: 4.0 to 12.0, p < 0.001). The effect of amodiaquine on the heart rate of children aged <12 years compared with other antimalarials was not clinically significant. Study limitations include the unavailability of individual patient-level adverse event data for most included participants, but no serious complications were documented. CONCLUSIONS: While caution is advised in the use of amodiaquine in patients aged ≥12 years with concomitant use of heart rate-reducing medications, serious cardiac conduction disorders, or risk factors for torsade de pointes, there have been no serious cardiovascular events reported after amodiaquine in widespread use over 7 decades. Amodiaquine and structurally related antimalarials in the World Health Organization (WHO)-recommended dose regimens alone or in ACTs are safe for the treatment and prevention of malaria.

Potential Cardiotoxic Effects of Remdesivir on Cardiovascular System: A Literature Review.

Corona disease 2019 (COVID-19) pandemic continues to spread around the world with no efficacious treatment. Intravenous remdesivir is the only authorized drug for treatment of COVID-19 disease under an Emergency Use Authorization. Remdesivir is a 1'-cyano-substituted adenosine nucleotide prodrug which inhibits viral RNA synthesis. This metabolite is an adenosine analog but with a significantly longer half-life than adenosine. Adenosine is a powerful vasodilator that can cause profound hypotension which is followed by the compensatory release of catecholamines. It can also shorten atrial action potential and refractoriness and lead to atrial fibrillation (AF). These effects may also occur in ventricular cells and predispose patients to ventricular fibrillation. Remdesivir can also induce significant cytotoxic effects in cardiomyocytes that is considerably worse than chloroquine cardiotoxic effects. Remdesivir-induced cardiotoxicity is due to its binding to human mitochondrial RNA polymerase. On the other hand, remdesivir can increase field potential duration with decreased Na+ peak amplitudes and spontaneous beating rates in a dose-dependent manner that might induce prolonged QT interval and torsade de point. There are some reports of sinus bradycardia, hypotension, T-wave abnormalities, AF, and a prolonged QT interval and few cases of cardiac arrest and complete heat block following remdesivir infusion. It seems remdesivir have some cardiotoxic and proarrhythmic effects that are especially more pronounced in patients with previous cardiovascular diseases. The current safety profile of remdesivir is still not completely known and further prospective clinical trials are needed to assess its safety profile and potential adverse cardiovascular effects.

Remdesivir induces persistent mitochondrial and structural damage in human induced pluripotent stem cell-derived cardiomyocytes.

AIMS: Remdesivir is a prodrug of an adenosine triphosphate analogue and is currently the only drug formally approved for the treatment of hospitalized coronavirus disease of 2019 (COVID-19) patients. Nucleoside/nucleotide analogues have been shown to induce mitochondrial damage and cardiotoxicity, and this may be exacerbated by hypoxia, which frequently occurs in severe COVID-19 patients. Although there have been few reports of adverse cardiovascular events associated with remdesivir, clinical data are limited. Here, we investigated whether remdesivir induced cardiotoxicity using an in vitro human cardiac model. METHODS AND RESULTS: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were exposed to remdesivir under normoxic and hypoxic conditions to simulate mild and severe COVID-19, respectively. Remdesivir induced mitochondrial fragmentation, reduced redox potential, and suppressed mitochondrial respiration at levels below the estimated plasma concentration under both normoxic and hypoxic conditions. Non-mitochondrial damage such as electrophysiological alterations and sarcomere disarray were also observed. Importantly, some of these changes persisted after the cessation of treatment, culminating in increased cell death. Mechanistically, we found that inhibition of DRP1, a regulator of mitochondrial fission, ameliorated the cardiotoxic effects of remdesivir, showing that remdesivir-induced cardiotoxicity was preventable and excessive mitochondrial fission might contribute to this phenotype. CONCLUSIONS: Using an in vitro model, we demonstrated that remdesivir can induce cardiotoxicity in hiPSC-CMs at clinically relevant concentrations. These results reveal previously unknown potential side-effects of remdesivir and highlight the importance of further investigations with in vivo animal models and active clinical monitoring to prevent lasting cardiac damage to patients.

Effects of cardiac toxicity of combination therapy with hydroxychloroquine and azithromycin in COVID-19 patients.

Coronavirus disease 2019 (COVID-19), which began in China, caused a global pandemic. Few studies have shown the benefit of hydroxychloroquine (HY) ± azithromycin (AZ) for treating COVID-19. Concerns of QT prolongation and increased risks of torsade's de pointes (TdP) with this combination have been raised since each agent can individually prolong the QT interval. This retrospective, observational study included hospitalized patients treated with HY and AZ from March 2020 to May 2020 at a large community hospital. Serial assessments of the QT interval were performed. Our aim is to evaluate the safety and characterize the change in QTc interval and arrhythmic events in COVID-19 patients treated with HY/AZ. A total of 21 COVID patients who received at least four days of HY and AZ were included in this study. Mean baseline was QTc 403 ms, mean maximum QTc was 440 ms, mean change in QTc was 36 ms. Only one patient (4.8%) developed prolonged QTc > 500 ms. No patient had a change in QTc of 60 ms or more. No patient developed TdP. Fifteen patients (71.4%) had hypoxia on admission, with only two patients (9.5%) required oxygen of 1-2 L at discharge. 80.9% of patients have been discharged home or inpatient rehabilitation.