Immunohistochemical localization of endothelial cell-derived lipase in atherosclerotic human coronary arteries

OBJECTIVE: A novel lipoprotein lipase (LPL)-like gene, endothelial cell-derived lipase (EDL), was recently cloned from vascular endothelial cells. The presence of LPL in the vascular wall has been implicated in the progression of atherosclerosis through the bridging function between lipoprotein particles and matrix proteoglycans to enhance lipoprotein uptake into the vascular wall. The aim of this study was to investigate the local expression of EDL in human coronary arteries. METHODS AND RESULTS: Human coronary arterial specimens from 10 autopsied cases were examined by immunohistochemistry with polyclonal antibodies against specific synthetic EDL peptides. Immunohistochemical analysis revealed that EDL was expressed in endothelial cells and medial smooth muscle cells in non-atherosclerotic coronary arteries. In addition, EDL was expressed in infiltrating cells within atheromatous plaques as well as endothelial and smooth muscle cells. Double labeling immunofluorescence confirmed EDL positive-cells were endothelial cells, smooth muscle cells and macrophages. EDL immunoreactivity was also detected in neovasculature within atheromatous plaques in atherosclerotic coronary arteries. CONCLUSIONS: These results suggest that EDL may have unique functional roles in the pathogenesis of coronary artery diseases such as atherosclerosis as well as in lipid metabolism in the vessel wall.