title: Increased expression of CD44 in hypertrophied ligamentum flavum and relevance of splice variants CD44v5 and CD44v6.
abstract: BACKGROUND
  The most common spinal disorder in the elderly is lumbar spinal stenosis (LSS), which results in part from ligamentum flavum (LF) hypertrophy. Although prior histologic and immunochemical studies have been performed in this area, the pathophysiology of loss of elasticity and hypertrophy is not completely understood. The purpose of this immunohistological study is to elucidate the role of CD44 and its splice variants CD44v5 and CD44v6 in the hypertrophied LF obtained from patients with lumbar spinal stenosis (LSS).
  
  
  METHODS
  LF samples of 38 patients with LSS were harvested during spinal decompression. Twelve LF samples obtained from patients with disc herniation and no visible degeneration on preoperative MRI were obtained as controls. Samples were dehydrated and embedded in paraffin. For immunohistochemical determination, slices were stained with antibodies against CD44, Cd44v4, and CD44v6 stained with DAB. LF hypertrophy and cross-sectional area (CSA) were measured with T1-weighted MRI.
  
  
  RESULTS
  CD44 and CD44v5 expression were significantly increased in the hypertrophy group (p < 0.05). CD44v6 expression was not significantly increased. The number of elastic fibers was significantly higher in the hypertrophy group. In the hypertrophy group, LF thickness was significantly increased while CSA was significantly decreased. There was a statistical correlation between LF thickness, CSA, CD44, and CD44v5 expression in the hypertrophy group (p < 0.05).
  
  
  CONCLUSIONS
  LF hypertrophy is accompanied by increased CD44 and CD44v5 expression. CD44v6 expression is not enhanced in LF hypertrophy.
authors: Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, 35043 Marburg, Germany. lakemeie@med.uni-marburg.de
authors: Stefan
authors: S
authors: Lakemeier
authors: Raphael
authors: R
authors: Schmid
authors: Lisa
authors: L
authors: Foltz
authors: Jochen
authors: J
authors: Rohlfs
authors: Susanne
authors: S
authors: Fuchs-Winkelmann
authors: Turgay
authors: T
authors: Efe
authors: Christian
authors: C
authors: Foelsch
authors: Jürgen R J
authors: JR
authors: Paletta
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006984:Hypertrophy / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D007150:Immunohistochemistry; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000378:metabolism* / Q000473:pathology*; D017843:Ligamentum Flavum / Q000378:metabolism* / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D013130:Spinal Stenosis / Q000175:diagnosis / Q000209:etiology
chemical_list: D015415:Biomarkers; D018960:Hyaluronan Receptors