title: Intensity of C-reactive protein immunohistochemical staining of atherosclerotic plaque macrophages and extracellular tissue of patients with angina pectoris undergoing directional coronary atherectomy.
abstract: BACKGROUND
  An elevated C-reactive protein (CRP) level plays a crucial role in cell biology of atherosclerosis and unstable plaque formation. However, direct evidence of CRP involvement in atherosclerotic plaque development and vulnerability is still limited. We hypothesized that CRP is present in the vulnerable plaques and that CRP staining intensity is stronger in vulnerable plaques compared to stable plaques.
  
  
  METHODS
  Directional coronary atherectomy (DCA) was performed on 58 patients with stable angina (group 1) and 40 patients with unstable angina (group 2). White blood cell (WBC) counts were measured prior to DCA. Immunohistochemical staining (IHCS) was performed to localize CRP in the atheroma. Staining intensity in macrophages and extracellular tissue was graded as: 0, no staining; 1+, < 30%; 2+, 30%-60%; 3+, > 60%.
  
  
  RESULTS
  The IHCS demonstrated that CRP staining - 1+ intensity in macrophages and extracellular tissue were significantly higher in group 1 than in group 2 patients (all p values < 0.0001). However, IHCS demonstrated that CRP staining a 2+ intensity in macrophages and extracellular tissue were significantly higher in group 2 than in group 1 patients (all p values < 0.0001). By multiple analysis, only stable angina was independently associated with CRP staining : 1+ intensity in both macrophages and extracellular tissue (p < 0.0001), whereas unstable angina and WBC counts were independent predictors of CRP staining > or = 2+ intensity in both macrophages and extracellular tissue (p < 0.0001).
  
  
  CONCLUSIONS
  CRP was frequently found in atherosclerotic plaques of patients with unstable angina. This analytical finding suggests that CRP directly mediates an inflammatory process in the atherosclerotic plaque.
authors.affiliation: Division of Cardiology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Tzu-Hsien
authors.initials: TH
authors.lastname: Tsai
authors.forename: Sarah
authors.initials: S
authors.lastname: Chua
authors.forename: Cheng-Hsu
authors.initials: CH
authors.lastname: Yang
authors.forename: Chi-Ling
authors.initials: CL
authors.lastname: Hang
authors.forename: Yuan-Kai
authors.initials: YK
authors.lastname: Hsieh
authors.forename: Yen-Hsun
authors.initials: YH
authors.lastname: Chen
authors.forename: Han-Tan
authors.initials: HT
authors.lastname: Chai
authors.forename: Kuo-Ho
authors.initials: KH
authors.lastname: Yeh
authors.forename: Hon-Kan
authors.initials: HK
authors.lastname: Yip
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000378:metabolism* / Q000601:surgery; D017225:Atherectomy, Coronary; D050197:Atherosclerosis / Q000378:metabolism*; D002097:C-Reactive Protein / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D013194:Staining and Labeling
chemical_list: D002097:C-Reactive Protein