title: Cortistatin is endogenous to the human intervertebral disc and exerts in vitro mitogenic effects on annulus cells and a downregulatory effect on TNF-α expression.
abstract: BACKGROUND
  Cortistatin (CST) is a recently discovered cyclic neuropeptide with biologic anti-inflammatory properties relevant to disc degeneration.
  
  
  OBJECTIVE
  To test whether CST is present in the disc tissue, whether its expression is influenced by tumor necrosis factor-α (TNF-α), and whether it influences cell proliferation.
  
  
  METHODS
  Institutional review board-approved study using immunohistochemistry on human disc tissue, in vitro annulus cultures to determine the effect of CST on cell proliferation, and the effect of TNF-α on CST gene expression.
  
  
  METHODS
  Discs from 12 subjects used for immunohistochemistry, four annulus specimens used for cell culture with proinflammatory cytokines, and 11 used for cell proliferation analyses.
  
  
  METHODS
  Immunohistochemical localization of CST, gene expression of CST, and cell proliferation analyses.
  
  
  METHODS
  Immunohistochemistry localized CST in disc tissue. Microarray analysis measured CST gene expression. Human annulus cells were exposed to CST for proliferation tests or cultured for the effect of TNF-α on CST expression. Standard statistical analyses were performed.
  
  
  RESULTS
  Immunohistochemistry identified CST in outer annulus, inner annulus, and nucleus tissue. Annulus cells exposed to TNF-α revealed significantly lower CST expression (p=.013). Exposure to CST significantly increased proliferation. Quantitative real-time polymerase chain reaction also confirmed expression of CST in vitro.
  
  
  CONCLUSIONS
  Data provide the first evidence that CST is present in the human disc. Addition of CST significantly increased cell proliferation. Cortistatin expression was significantly downregulated by TNF-α exposure in vitro. Findings suggest possible in vivo reduction of the anti-inflammatory actions of CST because of elevated proinflammatory cytokines during degenerating disc.
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA. Electronic address: helen.gruber@carolinashealthcare.org.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Gruber
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA.
authors.forename: Gretchen L
authors.initials: GL
authors.lastname: Hoelscher
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA.
authors.forename: Synthia F
authors.initials: SF
authors.lastname: Bethea
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA.
authors.forename: Evan A
authors.initials: EA
authors.lastname: Menscher
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Ingram
authors.affiliation: Dickson Advanced Analytics, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA.
authors.forename: Megan A
authors.initials: MA
authors.lastname: Templin
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28232, USA.
authors.forename: Edward N
authors.initials: EN
authors.lastname: Hanley
mesh_terms: D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D015536:Down-Regulation; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009479:Neuropeptides / Q000378:metabolism / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: D000893:Anti-Inflammatory Agents; D009479:Neuropeptides; D014409:Tumor Necrosis Factor-alpha; C099323:cortistatin
keywords: Cell proliferation; Cortistatin; Disc degeneration; Gene expression; Immunohistochemistry; TNF-alpha