Standardized high throughput screening of contractile tissues for drug discovery using Ethica M

Cardiovascular diseases, with high mortality and incidence rates, drive development of drugs and treatments. Off-target effects resulting from insufficient models are responsible for 45% of drug withdrawals. Engineered heart tissues (EHT) from hiPSC cardiomyocytes are gaining traction in New Approach Methodologies (NAM) as they better recapitulate human physiology and functions, however, lack of standardization and throughput are impeding their industrial adoption. Objectives: Using the Ethica M platform, with the MChip to: 1. Study tissue formation and contractile maturation of EHTs 2. Validate function with force frequency relationship (FFR) and compound addition 3. Validate the ability of an automated high-throughput system to generate robust, reproducible EHTs for drug screening applications Cell/gel matrix was dispensed and tissues formed in 2 days. Spontaneous beating was tracked and videos recorded daily during the study. Continuous electrical pacing started on day 9 up to endpoint assays of FFR and compound exposure. After initial tissue formation (85%), irregular spontaneous beating began at d2, stabilizing at 0.6 Hz (day 5). Maturation was assessed by recording contraction amplitude, beat rate and pulse width. Within 14 days, spontaneous contraction amplitudes of previously stimulated tissues increased by 64%, while pacing the same tissues increased amplitudes by 165%. Contraction increases were accompanied by a beat rate reduction of 38% (0.91–0.56 Hz) and a 15% pulse width decrease, indicating a shift from fetal to adult phenotype as maturation processes in sarcomere structures, electrophysiology and calcium handling result in stronger, shorter contractions and a lower beat rate. Tissues were exposed to inotropic compounds (d31). Isoprenaline showed increased contraction strength (positive inotrope), EC 50 = 9 ± 2 nM, while Nifedipine showed negative inotropy with an amplitude reduction, IC 50 = 41 ± 3 nM. In both cases, tissues showed dose-dependent responses mimicking the response of mature cardiomyocytes. Functional maturity was confirmed by FFR. Electrical stimulation ranged from 0.8 to 4 Hz showing positive FFR correlation for frequencies up to 2.2 Hz, recapitulating the response of human myocardium. We demonstrate the ability of Ethica M to produce mature EHTs suitable for screening workflows that may recapitulate expected drug compound and FFR responses of the human myocardium.