Quantifying Cardiomyocyte Alignment and Contractility

Sarcomere energetics was assessed in Triton permeabilized strips of mutant and donor ventricular samples.^{6 (link)} To exclude myocardial disarray as an artificial contributor to mechanical and energetic data, we employed a novel method able to quantify myocyte alignment, disarray, and contractile tissue content in tissue strips.^{22 (link)} The local cardiomyocyte’s orientation was detected with cellular resolution and represented as 3D vectors. Global Alignment quantifies the average alignment degree of the cells along the longitudinal axis of the preparation (Y), while local disarray quantifies the misalignment degree of nearby orientation vectors with respect to the mean local direction of the cells. The percentage of contractile tissue in the preparation is quantified as the ratio between the effective volume of labeled tissue (ie, total volume of cardiomyocytes thanks to the high-specificity of anti-α-actinin antibody staining) and the total volume of the preparation.