title: Kallikrein-related peptidase 6: a biomarker for traumatic brain injury in the rat.
abstract: BACKGROUND
  Establishment of a traumatic brain injury (TBI)-sensitive biomarker or identification of a key therapeutic agent would significantly improve clinicians' efforts to diagnose and treat TBI, thereby promoting improved outcomes for patients. Numerous studies support the role of kallikrein-6 (Klk6) as a critical component of neuroinflammation and demyelination. This study assesses whether Klk6 is implicated in the secondary mechanisms of TBI and subsequently if serum levels of Klk6 are useable as a biomarker.
  
  
  METHODS
  The abundance of Klk6 following controlled cortical impact (CCI) of the medial prefrontal cortex to a depth of either 3.0 mm (severe) or 1.5 mm (moderate) was quantified. Uninjured and rats subjected to craniotomy-only were used as controls. Protein levels were quantified with Western-blotting, enzyme-linked immunosorbent assay and immunohistochemistry.
  
  
  RESULTS
  Severe and moderate CCI resulted in significant elevation of Klk6 in the contusion-core (~12-fold-increase, p < 0.0001) and serum (~5-fold-increase, p < 0.01) compared to controls. In all cases, Klk6 elevation was resolved within 72 hours.
  
  
  CONCLUSIONS
  Serum levels of Klk6 are a statistically significant indicator of TBI 24 hours after CCI and thus may be of great utility to clinicians as a biomarker. These data strongly implicate Klk6 as a player in the neuroinflammation processes following CCI, although the specific mechanisms remain to be characterized.
authors.affiliation: Department of Biomedical Sciences, Florida State University , Tallahassee, FL , USA.
authors.forename: Helen W
authors.initials: HW
authors.lastname: Phipps
authors.forename: Liam M
authors.initials: LM
authors.lastname: Longo
authors.forename: Sachiko I
authors.initials: SI
authors.lastname: Blaber
authors.forename: Michael
authors.initials: M
authors.lastname: Blaber
authors.forename: Jacob W
authors.initials: JW
authors.lastname: Vanlandingham
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D001930:Brain Injuries / Q000150:complications / Q000378:metabolism*; D003711:Demyelinating Diseases / Q000209:etiology / Q000378:metabolism*; D007150:Immunohistochemistry; D007249:Inflammation / Q000209:etiology / Q000378:metabolism*; D007610:Kallikreins / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015599:Trauma Severity Indices
chemical_list: D015415:Biomarkers; D007610:Kallikreins