title: Macrophages are associated with lipid-rich carotid artery plaques, echolucency on B-mode imaging, and elevated plasma lipid levels.
abstract: OBJECTIVE
  Atherosclerosis may be regarded as an inflammatory disease dominated by macrophages. We tested whether macrophages in carotid artery atherosclerotic plaques are associated with echolucency on B-mode ultrasound imaging, lipid levels, inflammatory markers, and aspirin use.
  
  
  METHODS
  We studied 106 patients undergoing carotid endarterectomy having >/=50% carotid artery stenosis and previous ipsilateral hemispheric neurologic symptoms.
  
  
  RESULTS
  Macrophages were particularly common in plaques with a high content of lipid and hemorrhage and, conversely, rare in plaques dominated by calcification and fibrous tissue. Macrophage density in carotid artery plaques classified by B-mode ultrasound imaging as echolucent (n = 56), intermediate (n = 25), or echorich (n = 25) was 1.8% +/- 0.2%, 1.5% +/- 0.4%, and 1.0% +/- 0.2% (+/-SE), respectively (analysis of variance, P =.02). A computer-generated measure of plaque echolucency, gray-scale median, was associated with increased macrophage density (r = -0.31; P =.002). Furthermore, plasma and low-density lipoprotein cholesterol levels were associated with carotid artery macrophage density (r = 0.26, P =.008 and r = 0.23, P =.02); this was most pronounced in patients with lipid-rich plaques. Macrophage density was not associated with plasma levels of acute-phase reactants. Finally, macrophage density in carotid artery plaques of users (n = 55) and nonusers of aspirin (n = 51) was 1.2% +/- 0.2% and 1.8% +/- 0.2% (t test, P =.01).
  
  
  CONCLUSIONS
  Increased macrophage density in carotid atherosclerotic plaques was associated with lipid content, plaque echolucency, and increased plasma and low-density lipoprotein cholesterol levels. Furthermore, use of aspirin was associated with reduced macrophage density in carotid artery plaques.
authors.affiliation: Department of Vascular Surgery, Gentofte Hospital, Universities of Copenhagen and Aarhus, Denmark. mlg@dadlnet.dk.
authors.forename: Marie-Louise M
authors.initials: ML
authors.lastname: Grønholdt
authors.forename: Børge G
authors.initials: BG
authors.lastname: Nordestgaard
authors.forename: Jacob
authors.initials: J
authors.lastname: Bentzon
authors.forename: Britt M
authors.initials: BM
authors.lastname: Wiebe
authors.forename: Ji
authors.initials: J
authors.lastname: Zhou
authors.forename: Erling
authors.initials: E
authors.lastname: Falk
authors.forename: Henrik
authors.initials: H
authors.lastname: Sillesen
mesh_terms: D000704:Analysis of Variance; D001241:Aspirin / Q000494:pharmacology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D002340:Carotid Artery Diseases / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D016893:Carotid Stenosis / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D016894:Endarterectomy, Carotid; D005260:Female; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D008055:Lipids / Q000097:blood*; D008163:Luminescent Measurements; D008264:Macrophages / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D014463:Ultrasonography
chemical_list: D005343:Fibrinolytic Agents; D018836:Inflammation Mediators; D008055:Lipids; D001241:Aspirin