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.

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.

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.