Regression of Left Ventricular Hypertrophy After Surgical Therapy for Aortic Stenosis Is Associated With Changes in Extracellular Matrix Gene Expression

Abstract
Background Regression of left ventricular hypertrophy (LVH) after surgical correction for aortic stenosis is not fully understood on the molecular level. The aim of this study was to examine whether there is an association between LVH regression and extracellular matrix (ECM) gene expression. Methods and Results A standard model of controlled LVH induction by supracoronary banding (A=baseline) was applied in 44 growing sheep (age, 6 to 8 months). Surgical correction to release the pressure gradient was performed 8.3±1 months later (B). The animals were killed after another 10.1±2 months (C). At all time points, hemodynamic evaluations and quantitative analysis of mRNA and protein expression for matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) was performed. Left ventricular mass index was 82±21 (A) versus 150±33 (B), P2 (C), PP2 (C), PConclusions Controlled induction of compensated LVH leads to significant increase in ECM gene expression. The regression of LVH after surgical therapy is associated with complete regression of ECM gene expression. However, no cause-and-effect relation could be demonstrated.