Abnormal Accumulation of Reactive Oxygen Species from Pitx2 Mutation Could Cause HLHS

Abstract

Hypoplastic Left Heart Syndrome (HLHS) is a highly rare congenital heart defect in which the left side of the heart is critically underdeveloped. At the cellular level, changes in ventricular structure include myocyte growth and myocyte apoptosis. Ultimately, this progressive remodeling can result in heart failure and, in HLHS, premature death. Recent progress in understanding these mechanisms of myocardial remodeling has led to evidence that reactive oxygen species (ROS) and oxidative stress play a central role in regulating the phenotype of cardiac myocytes. We hypothesize that ROS-mediated developmental destabilization due to pitx2 dysfunction in the left ventricle, coupled with the low and high strain placed on the interventricular septum (IV) and left ventricular (LV) wall during cardiac contraction, respectively, causes HLHS. Genetic tests of mouse models and in vitro studies of cardiomyocytes confirm this proposed progression. Further investigation could open the door to curative gene therapy and prevent many years of suffering and complications with surgical procedures for affected infants