title: Identifying sources and estimating glandular output of salivary TIMP-1.
abstract: OBJECTIVE
  Tissue inhibitor of metalloproteinases 1 (TIMP-1) has been identified as a potential biomarker in diseases such as cancer, cardiovascular diseases and diabetes. Since TIMP-1 resides in most tissues and bodily fluids, we evaluated the potential of using saliva to obtain reproducible TIMP-1 measurements in a non-invasive manner.
  
  
  METHODS
  Samples of unstimulated and stimulated whole saliva and saliva collected from individual glands were analysed for TIMP-1 content. A TIMP-1 ELISA was validated for use in saliva testing and the most optimal sampling and handling procedures for reproducible measurements identified. Western blotting and MALDI-TOF mass spectrometry were used for confirmatory analyses.
  
  
  RESULTS
  The TIMP-1 ELISA was found suitable for saliva measurements. All saliva secretions contained TIMP-1, but in different concentrations ranging from 2.81 ng/mL in submandibular/sublingual saliva to 173.88 ng/mL in parotid saliva. TIMP-1 concentrations were influenced to a varying degree by fluctuations in flow. We found the lowest output in submandibular/sublingual saliva stimulated with 0.5% citric acid (3.56 ng/min) and highest output in chewing-stimulated whole saliva (267.01 ng/min).
  
  
  CONCLUSIONS
  This study shows that saliva contains authentic TIMP-1, the concentration of which was found to depend on gland type and salivary flow. Stimulated whole saliva is suggested as a reliable and easily accessible source for TIMP-1 determinations in bodily fluids.
authors.affiliation: Department of Oral Medicine, Clinical Oral Physiology, Oral Pathology & Anatomy, Institute of Odontology, Faculty of Health Sciences, University of Copenhagen, Copenhagen N, Denmark. lho@odont.ku.dk
authors.forename: L
authors.initials: L
authors.lastname: Holten-Andersen
authors.forename: S Beier
authors.initials: SB
authors.lastname: Jensen
authors.forename: A
authors.initials: A
authors.lastname: Bardow
authors.forename: J
authors.initials: J
authors.lastname: Harslund
authors.forename: M
authors.initials: M
authors.lastname: Thaysen-Andersen
authors.forename: U
authors.initials: U
authors.lastname: Lademann
authors.forename: P Autzen
authors.initials: PA
authors.lastname: Usher
authors.forename: H
authors.initials: H
authors.lastname: Offenberg
authors.forename: P
authors.initials: P
authors.lastname: Højrup
authors.forename: J
authors.initials: J
authors.lastname: Reibel
authors.forename: H J
authors.initials: HJ
authors.lastname: Nielsen
authors.forename: N
authors.initials: N
authors.lastname: Brünner
authors.forename: B
authors.initials: B
authors.lastname: Nauntofte
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008409:Mastication; D010306:Parotid Gland / Q000737:chemistry / Q000378:metabolism*; D012463:Saliva / Q000737:chemistry*; D012470:Salivary Glands, Minor / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1