title: Expression of ADAMTS-4 (aggrecanase-1) and possible involvement in regression of lumbar disc herniation.
abstract: METHODS
  Examination of ADAMTS-4 expression, and cellular lineages, distribution, and numbers of ADAMTS-4 (aggrecanase-1) expressing cells in herniated lumbar intervertebral discs.
  
  
  OBJECTIVE
  To determine the expression of ADAMTS-4, a metalloproteinase capable of digesting aggrecan, and its role in herniated lumbar intervertebral disc degradation.
  
  
  BACKGROUND
  Matrix metalloproteinases degrade extracellular matrix of herniated discs, but the mechanism of aggrecan degradation, the major component of intervertebral discs, is poorly understood.
  
  
  METHODS
  Surgically resected herniated lumbar intervertebral discs from 22 patients were subclassified into protrusion, subligamentous extrusion, transligamentous extrusion, and sequestration types. Reverse transcriptase polymerase chain reaction, Western blot, and immunohistochemistry were used to evaluate ADAMTS-4 messenger ribonucleic acid and protein expression.
  
  
  RESULTS
  Expression of ADAMTS-4 messenger ribonucleic acid and protein was shown in the samples of herniated lumbar intervertebral discs. Immunohistochemical staining showed that ADAMTS-4 was mainly localized in CD68-positive mononuclear cells in granulation and adjacent disc tissues. ADAMTS-4 positive cell counts were significantly higher in transligamentous extrusion and sequestration than protrusion and subligamentous extrusion types. Alcian blue staining showed a decrease of proteoglycan in transligamentous extrusion and sequestration cases.
  
  
  CONCLUSIONS
  Macrophages infiltrating granulation and adjacent disc tissues express ADAMTS-4, suggesting its involvement in herniated disc regression.
authors.affiliation: Department of Pathology, Kanazawa Medical University, Ishikawa, Japan.
authors.forename: Eiju
authors.initials: E
authors.lastname: Hatano
authors.forename: Takuya
authors.initials: T
authors.lastname: Fujita
authors.forename: Yoshimichi
authors.initials: Y
authors.lastname: Ueda
authors.forename: Tetsuhito
authors.initials: T
authors.lastname: Okuda
authors.forename: Shogo
authors.initials: S
authors.lastname: Katsuda
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Okada
authors.forename: Tadami
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000071121:ADAMTS4 Protein; D000328:Adult; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000201:enzymology / Q000473:pathology; D007405:Intervertebral Disc Displacement / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D008264:Macrophages / Q000201:enzymology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011348:Procollagen N-Endopeptidase / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012075:Remission, Spontaneous; D014018:Tissue Distribution
chemical_list: D012333:RNA, Messenger; D051722:ADAM Proteins; D011348:Procollagen N-Endopeptidase; D000071121:ADAMTS4 Protein; C000603918:ADAMTS4 protein, human