Abstract P1033: A Simple 2-D Assay For Measuring Contraction And Calcium Kinetics In Engineered Human Cardiomyocytes To Model Duchenne Muscular Dystrophy

Abstract

Duchenne muscular dystrophy (DMD) is caused by the loss of the dystrophin protein, resulting in progressive muscle wasting, loss of ambulation, and early mortality in the second and third decades of life. While the skeletal muscle phenotype is most prominently associated with DMD, heart failure is the leading cause of death in DMD patients, and therapies remain limited. Advancements in stem cell-derived models and assays for heart disease have exciting translational potential for DMD, such as patient-specific modeling and drug screening. Contracting 2-D monolayers and organoids are standards of cardiac engineering, but measuring contraction is challenging due in part due to multi-axial alignment of immature sarcomeres. Complicated solutions to measure contraction in stem cell models use fluorescent beads to infer contraction, transgenic systems that express fluorescent proteins, 3-D scaffolding, and/or custom hardware and software. Here, we utilize a common microscope system used for measuring mature cardiomyocyte (IonOptix) and a commercially-available module (CytoMotion) that measures changes in pixel intensity to index contraction. This platform allows simultaneous measurement of contraction motion and calcium transients just like with adult mammalian cardiomyocytes. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) from a Duchenne muscular dystrophy (DMD) patient and a healthy relative, we demonstrate DMD hiPSC-CM exhibit impaired contraction and calcium handling. We have since further increased the output of our assay using a custom 24-well stimulation plate, and current studies are using this workflow to validate experimental therapies that show promise from mouse models of DMD.