Wnt Site Signaling Inhibitor Secreted Frizzled-Related Protein 3 Protects Mitral Valve Endothelium From Myocardial Infarction-Induced Endothelial-to-Mesenchymal Transition.

Background The onset and mechanisms of endothelial-to-mesenchymal transition (EndMT) in mitral valve (MV) leaflets following myocardial infarction (MI) are unknown, yet these events are closely linked to stiffening of leaflets and development of ischemic mitral regurgitation. We investigated whether circulating molecules present in plasma within days after MI incite EndMT in MV leaflets. Methods and Results We examined the onset of EndMT in MV leaflets from 9 sheep with inferior MI, 8 with sham surgery, and 6 naïve controls.

Ovine Model of Ischemic Mitral Regurgitation.

Ischemic mitral regurgitation (IMR) is a common complication of ischemic heart disease that doubles mortality after myocardial infarction and is a major driving factor increasing heart failure. IMR is caused by left ventricular (LV) remodeling which displaces the papillary muscles that tether the mitral valve leaflets and restrict their closure. IMR frequently recurs even after surgical treatment.

CD45 Expression in Mitral Valve Endothelial Cells After Myocardial Infarction.

Rationale: Ischemic mitral regurgitation, a complication after myocardial infarction (MI), induces adaptive mitral valve (MV) responses that may be initially beneficial but eventually lead to leaflet fibrosis and MV dysfunction. We sought to examine the MV endothelial response and its potential contribution to ischemic mitral regurgitation.

Objective: Endothelial, interstitial, and hematopoietic cells in MVs from post-MI sheep were quantified.

Efficacy of polymer injection for ischemic mitral regurgitation: persistent reduction of mitral regurgitation and attenuation of left ventricular remodeling.

Objectives: The aim of this study was to examine the chronic effects of polyvinyl-alcohol (PVA) injection on mitral regurgitation (MR) reduction, mitral valve geometry, and left ventricular (LV) remodeling in a chronic ischemic MR sheep model.

Background: Previous studies have demonstrated acute efficacy of PVA hydrogel polymer injection into infarcted myocardium underlying the papillary muscle to relieve MR by papillary muscle repositioning. However, the chronic efficacy of PVA injection in the chronic infarction setting remains unclear.