title: Enhanced extracellular matrix accumulation in restenosis of coronary arteries after stent deployment.
abstract: OBJECTIVE
  The goal of this study was to evaluate the cellular and extracellular composition of human coronary arterial in-stent restenosis after various periods of time following stent deployment.
  
  
  BACKGROUND
  Neointimal in-growth rather than stent recoil is thought to be important for coronary arterial in-stent restenosis. There is only limited data on the cellular and extracellular composition changes with time after stent deployment.
  
  
  METHODS
  We analyzed 29 coronary arterial in-stent restenotic tissue samples (14 left anterior descending coronary artery, 10 right coronary artery, and 5 left circumflex artery) retrieved by using directional coronary atherectomy from 25 patients at 0.5 to 23 (mean, 5.7) months after deployment of Palmaz-Schatz stents employing histochemical and immunocytochemical techniques.
  
  
  RESULTS
  Cell proliferation was low (0% to 4%). Myxoid tissue containing extracellular matrix (ECM) enriched with proteoglycans was found in 69% of cases and decreased over time after stenting. Cell-depleted areas were found in 57% of cases and increased with time after stenting. Versican, biglycan, perlecan, and hyaluronan were present with varying individual distributions in all samples. Positive transforming growth factor-beta1 staining was found in 80% of cases. Immunostaining with alpha-smooth muscle actin identified the majority of cells as smooth muscle cells with occasional macrophages present (< or =12 cells per section).
  
  
  CONCLUSIONS
  These data suggest that enhanced ECM accumulation rather than cell proliferation contribute to later stages of in-stent restenosis. Balloon angioplasty of in-stent restenosis may, therefore, fail due to ECM changes during: 1) additional stent expansion, 2) tissue extrusion out of the stent, or 3) tissue compression.
authors.affiliation: Department of Pathology, University of Washington, Seattle, USA.
authors.forename: Ick-Mo
authors.initials: IM
authors.lastname: Chung
authors.forename: Herman K
authors.initials: HK
authors.lastname: Gold
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Schwartz
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikari
authors.forename: Michael A
authors.initials: MA
authors.lastname: Reidy
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Wight
mesh_terms: D000368:Aged; D017225:Atherectomy, Coronary; D002455:Cell Division; D003326:Coronary Circulation; D023903:Coronary Restenosis / Q000209:etiology / Q000473:pathology*; D003331:Coronary Vessels / Q000166:cytology* / Q000473:pathology; D005109:Extracellular Matrix / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000166:cytology; D015607:Stents / Q000009:adverse effects*
chemical_list: D019394:Ki-67 Antigen