Endothelial lipase is highly expressed in macrophages in advanced human atherosclerotic lesions

Research output: Contribution to journalJournal articlepeer-review

  • Bartels, Emil Daniel
  • John E Nielsen
  • Marie Louise Skakkebæk Lindegaard
  • Lillemor M Hulten
  • Torben V Schroeder
  • Lars B Nielsen
Endothelial lipase (EL) is expressed in endothelial cells, and affects plasma lipoprotein metabolism by hydrolyzing phospholipids in HDL. To determine the cellular expression of EL mRNA and protein in human atherosclerotic lesions, we performed in situ hybridization and immunohistochemical studies on sections of carotid endarterectomy specimens from patients with symptomatic cerebrovascular disease. In each of eight patients, EL mRNA and/or protein were seen in areas between the necrotic core and the fibrotic cap where they colocalized with LPL and macrophage-specific CD68. Moreover, there was a positive association between the expression of EL mRNA and CD68 mRNA in plaques from 26 patients. The impact of differentiation from monocytes into macrophages, and subsequently foam cells (by incubation with acetylated LDL) on expression was studied using THP-1 monocytes and primary human monocytes. EL mRNA expression increased markedly when either type of monocytes was differentiated into macrophages. Upon further differentiation into foam cells EL mRNA decreased whereas protein levels remained high compared to monocytes. In conclusion, macrophages in advanced human atherosclerotic lesions display high levels of EL expression, and the level of EL expression varies greatly during transformation of blood monocytes into foam cells.
Original languageEnglish
JournalAtherosclerosis
Volume195
Issue number2
Pages (from-to)e42-9
ISSN0021-9150
DOIs
Publication statusPublished - 1 Dec 2007

ID: 4032533