Ways to Study the Biology of Cardiomyocytes

Abstract

This chapter explains how experiments can be designed to investigate and quantify the biological function of cardiomyocytes. Cardiomyocytes are highly and terminally differentiated cells that are closely connected to each other in tissue. Isolation of cells requires disruption of cell-cell contacts without damaging these cells. This is performed by a transient depletion of extracellular calcium making reexposing of cardiomyocytes to a challenging procedure with slight methodological differences for cardiomyocytes from different species and parts of the heart. Under culturing conditions, cardiomyocytes rapidly adapt the specific conditions. The lack of mechanical load and loss of contractile activity leads to degradation of contractile units that requires specific attempts to analyze the behavior of such cells. This can be performed by mechanical load, electrical pacing, or induction of remodeling. Function of cardiomyocytes is mostly characterized by load-free cell shortening with remarkable reproducible results between cardiomyocytes from different species. Molecular aspects of cardiac hypertrophy can be analyzed by quantification of protein synthesis, protein degradation, and cell sizes. Although cardiomyocytes can be isolated and cultured from many species, the majority of researchers focused on small rodents, preferentially rats. These have a surprisingly strong comparability with other species in many aspects but not in electrophysiological aspects.