Abstract 16766: A Human Induced Pluripotent Stem Cell-Derived Engineered Cardiac Tissue Model of Pompe Disease

Abstract

Background: Infantile-onset Pompe disease is a lethal autosomal recessive lysosomal storage disorder caused by the complete loss of acid α-glucosidase activity resulting in glycogen accumulation within lysosomes. Skeletal and cardiac muscle pathology develop due to aberrant glycogen metabolism and lysosomal dysfunction. This work presents the first in vitro human cardiac tissue model of Pompe disease documenting the classic Pompe cellular phenotype within a multicellular engineered cardiac tissue preparation. Methods: Pompe disease-specific human induced pluripotent stem (iPS) cell derived cardiomyocyte (iPS-CMs) were seeded into a polymerizing fibrin mixture to form mechanically integrated multicellular engineered cardiac tissue (ECT) constructs that were evaluated over a one-month period in parallel with healthy human iPS cell derived ECTs. Weekly measurements of isometric force and intracellular calcium transients were recorded under varying work load imposed by electrical pacing and β1 adrenergic stimulation. Structural assessment was performed using electron microscopy and immunohistochemistry. Results: Healthy and Pompe iPS-CMs can form cylindrically shaped ECTs of 1-2 mm diameter and 1.5-2 cm in length composed of coupled CMs that generate force in the milli-newton range along the cylindrical axis. We report structural changes in the ECT model consistent with the hallmarks of Pompe disease including progressive intracellular glycogen accumulation, lysosomal disruption, and myofibrillar disarray. Both healthy and Pompe ECTs generate higher twitch forces in response to mechanical stretch, have a negative force-frequency relationship characteristic of immature myocardium, and have an inotropic response to dobutamine stimulation. Conclusion: Human iPS-CM ECTs obey the Frank-Starling law and produce calcium cycling and force kinetics that respond to β1 adrenergic stimulation. The Pompe ECT provides a novel cardiac tool in which to further study the pathophysiology of this disease and test novel therapeutic approaches.