Adverse effects of hydroxychloroquine and azithromycin on contractility and arrhythmogenicity revealed by human engineered cardiac tissues

Abstract

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic as declared by World Health Organization (WHO). In the absence of an effective treatment, different drugs with unknown effectiveness, including antimalarial hydroxychloroquine (HCQ), with or without concurrent administration with azithromycin (AZM), have been tested for treating COVID-19 patients with developed pneumonia. However, the efficacy and safety of HCQ and/or AZM have been questioned by recent clinical reports. Direct effects of these drugs on the human heart remain very poorly defined. To better understand the mechanisms of action of HCQ +/- AZM, we employed bioengineered human ventricular cardiac tissue strip (hvCTS) and anisotropic sheet (hvCAS) assays, made with human pluripotent stem cell (hPSC)-derived ventricular cardiomyocytes (hvCMs), which have been designed for measuring cardiac contractility and electrophysiology, respectively. Our hvCTS experiments showed that AZM induced a dose-dependent negative inotropic effect which could be aggravated by HCQ; electrophysiologically, as revealed by the hvCAS platform, AZM prolonged action potentials and induced spiral wave formations. Collectively, our data were consistent with reported clinical risks of HCQ and AZM on QTc prolongation/ventricular arrhythmias and development of heart failure. In conclusion, our study exposed the risks of HCQ/AZM administration while providing mechanistic insights for their toxicity. Our bioengineered human cardiac tissue constructs therefore provide a useful platform for screening cardiac safety and efficacy when developing therapeutics against COVID-19.

Fig. 1

(A) Representative tracings of hvCTS of vehicle (Control), hydroxychloroquine (HCQ), azithromycin (AZM) and the combined (HCQ + AZM) groups at 1.5 Hz pacing, normalized to baseline. (B) Bar graph showing force reduction of hvCTS by 100 μM AZM without (n = 5) and with (n = 5) 10 μM of HCQ. Concentration-response plot of developed force, maximum +dF/dt and maximum -dF/dt of (C-E) HES2-hvCTS (F-H) L-EdV-hvCTS for 1–10 μM HCQ (n = 3–7), 1–100 μM AZM (n = 3–5) and 1–100 μM AZM with 10 μM HCQ (n = 3–5) at 1.5 Hz pacing. B: Paired t-test between treated group and baseline; unpaired t-test between treated groups. C-H:: Two-way ANOVA test, followed by Holm-Sidak's multiple comparison to control group. All data are expressed as mean ± SEM. *p < 0.05, **p < 0.01 and ***p < 0.001.

Fig. 2

(A) Representative action potential tracings and (B) isochronal maps of hvCAS with vehicle (Control), 10 μM hydroxychloroquine (HCQ), 30 μM azithromycin (AZM) or the combined (HCQ + AZM) treatment. (C-E) Comparisons of re-entry percentage measured by number of observed re-entry phenomena divided by number of total experiments, % change in longitudinal (LCV) and transverse (TCV) conduction velocities of hvCAS (n = 5–6). (F-G) The change in APD₉₀ and the comparison of APD₉₀ at baseline or treated condition of hvCAS with different treatments (n = 5–6). D-F: One-way ANOVA test, followed by Holm-Sidak's multiple comparison to control. G: Two-way ANOVA test, followed by Holm-Sidak's multiple comparison to baseline. All data were expressed as mean ± SEM. *p < 0.05, **p < 0.01 and ***p < 0.001.