A new model for the research into rhythmic contraction activity of cardiomyocytes in vitro

hESC derived cardiomyocyte biosensor to detect the different types of arrhythmogenic properties of drugs

In the present work, we introduce a new cell-based biosensor for detecting arrhythmias based on a novel utilization of the combination of the Atomic Force Microscope (AFM) lateral force measurement as a nanosensor with a dual 3D cardiomyocyte syncytium. Two spontaneously coupled clusters of cardiomyocytes form this. The syncytium's functional contraction behavior was assessed using video sequences analyzed with Musclemotion ImageJ/Fiji software, and immunocytochemistry evaluated phenotype composition. The application of caffeine solution induced arrhythmia as a model drug, and its spontaneous resolution was monitored by AFM lateral force recording and interpretation and calcium fluorescence imaging as a reference method describing non-synchronized contractions of cardiomyocytes. The phenotypic analysis revealed the syncytium as a functional contractile and conduction cardiac behavior model. Calcium fluorescence imaging was used to validate that AFM fully enabled to discriminate cardiac arrhythmias in this in vitro cellular model. The described novel 3D hESCs-based cellular biosensor is suitable to detect arrhythmic events on the level of cardiac contractile and conduction tissue cellular model. The resulting biosensor allows for screening of arrhythmogenic properties of tailored drugs enabling its use in precision medicine.

Effects of cyclosporin A on contractile activity and cytoskeleton in chick embryo cardiomyocytes

The effects of cyclosporin A (CsA), a clinically used immunosupressive drug, on contractile activity of chick cardiomyocytes grown as small aggregates or explants suspended on a network of elastic glass fibres or cultured in a monolayer were analysed in vitro with computer-aided image cytometry methods. At therapeutic concentrations (200-1500 ng/mL), CsA induced changes in the frequency and amplitude of the beating activity of cardiomyocytes 15 min after application. Longer treatment of cardiomyocytes, for 20-24 h, additionally induced changes in their shape and cytoskeleton organization (F-actin and alpha-actinin distribution). These results indicate that CsA is able to affect directly the contractile activity, morphology, and cytoskeleton architecture of heart cells.Key words: heart, cardiomyocytes, contractibility, cyclosporin A, cytoskeleton, image analysis.