Abstract 549: High-Density Lipoprotein from Valvular Heart Disease and Cardiac Surgery Uncouples Endothelial Nitric Oxide Synthase Activity to Impair Vasodilation

Background: The vascular effects of high density lipoprotein (HDL) may be highly heterogeneous. Normal HDL protects vascular function. Vascular function plays an important role in maintaining the circulation stable post-cardiac surgery. The vascular effects of HDL in valvular heart disease (VHD) and cardiac surgery remain unknown. The present study is to determine the vascular effects of HDL from VHD and cardiac surgery. Methods: HDL was isolated from healthy subjects and patients with VHD and during cardiac surgery. HDL inflammation index was measured by cell free assay. Effects of HDL on vasodilation, protein interaction, generation of nitric oxide (NO) and superoxide anion (O 2 ·– ) were determined. Results: HDL inflammation index significantly increased in VHD patients and post-cardiac surgery. HDL from VHD patients and post-cardiac surgery significantly impaired endothelium-dependent vasodilation, inhibited both Akt and endothelial nitric oxide synthase (eNOS) phosphorylation, eNOS associated with heat shock protein 90, NO production and increased O 2 ·– generation. Conclusions: The vasoprotective effects of HDL from VHD patients and cardiac surgery is impaired by uncoupled eNOS activity. HDL may be a therapeutic target for maintaining the stable circulation in post-cardiac surgery.