Glycogen Synthase Kinase 3β Inhibition Improves Myocardial Angiogenesis and Perfusion in a Swine Model of Metabolic Syndrome.

BACKGROUND: Inhibition of glycogen synthase kinase 3β (GSK-3β) has been reported to be cardioprotective during stressful conditions.

METHODS AND RESULTS: Pigs were fed a high-fat diet for 4 weeks to develop metabolic syndrome, then underwent placement of an ameroid constrictor to their left circumflex artery to induce chronic myocardial ischemia. Two weeks later, animals received either: no drug (high cholesterol control group [HCC]) or a GSK-3β inhibitor (GSK-3β inhibited group [GSK-3βI]), which were continued for 5 weeks, followed by myocardial tissue harvest. Coronary blood flow and vessel density were significantly increased in the GSK-3βI group compared to the HCC group. Expression levels of the following proteins were greater in the GSK-3βI group compared to the HCC group: vascular endothelial growth factor receptor 1 , vascular endothelial cadherin, γ-catenin, β-catenin, protein kinase B, phosphorylated forkhead box O1, and superoxide dismutase 2.

CONCLUSIONS: In the setting of metabolic syndrome, inhibition of GSK-3β increases blood flow and vessel density in chronically ischemic myocardium. We identified several angiogenic, cell survival, and differentiation pathways that include β-catenin signaling and AKT/FOXO1, through which GSK-3β appears to improve vessel density and blood flow. These results may provide a potential mechanism for medical therapy of patients suffering from coronary artery disease and metabolic syndrome.