title: Osteocalcin expression in pulp inflammation.
abstract: BACKGROUND
  Dental pulp inflammation and repair are closely related. Osteocalcin (OCN), a glycoprotein present in dentin matrix, is expressed by odontoblasts. Although OCN is considered a reparative molecule inside the dental pulp, it is not clear if it is involved in pulpal inflammation. The objective of this study was to localize OCN in reversible and irreversible pulpitis and to describe its possible function in inflammation.
  
  
  METHODS
  Pulp tissues in the form of reversible and irreversible pulpitis were collected from the endodontic clinic. Those from impacted teeth were used as controls. Immunohistochemistry was used to localize OCN. Samples were analyzed for OCN and inflammatory mediator expression using multiplex assay.
  
  
  RESULTS
  OCN in inflamed tissues was localized in cells and matrix around calcification areas and in cells around blood vessels but not in normal tissues. The plex assay (Bio-Plex 200, Bio-Rad Laboratories Ltd, Mississauga, ON, Canada) showed OCN expression in reversible pulpitis significantly higher than in irreversible pulpitis, and both were significantly higher than in the controls. A panel of inflammatory mediators showed an increase in reversible and irreversible pulpitis. Another panel was decreased in both stages compared with the controls. OCN expression in reversible pulpitis was positively correlated to the expression of vascular endothelial growth factor, fibroblast growth factor, macrophage inflammatory protein-1β, monocyte-derived chemokine, monocyte chemoattractant protein-1, interleukin (IL)-17, and soluble IL-2 receptor α and negatively correlated to that of IL-1α, IL-1β, IL-8, granulocyte macrophage colony-stimulating factor, and macrophage inflammatory protein-1α.
  
  
  CONCLUSIONS
  Profound understanding of the pulp inflammatory process would lead to new molecular treatment strategies. Our data indicate that OCN expression in reversible pulpitis is associated with angiogenic markers, suggesting its potential use in regenerative treatment.
authors.affiliation: School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Abd-Elmeguid
authors.forename: Marwa
authors.initials: M
authors.lastname: Abdeldayem
authors.forename: Loren W
authors.initials: LW
authors.lastname: Kline
authors.forename: Redwan
authors.initials: R
authors.lastname: Moqbel
authors.forename: Harrisios
authors.initials: H
authors.lastname: Vliagoftis
authors.forename: Donald C
authors.initials: DC
authors.lastname: Yu
mesh_terms: D018932:Chemokine CCL2 / Q000032:analysis; D054405:Chemokine CCL3 / Q000032:analysis; D054407:Chemokine CCL4 / Q000032:analysis; D003094:Collagen / Q000032:analysis; D003782:Dental Pulp / Q000098:blood supply / Q000473:pathology; D003784:Dental Pulp Calcification / Q000473:pathology; D003804:Dentin / Q000473:pathology; D005346:Fibroblast Growth Factors / Q000032:analysis; D005355:Fibrosis; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis; D006801:Humans; D018836:Inflammation Mediators / Q000032:analysis; D020381:Interleukin-17 / Q000032:analysis; D053582:Interleukin-1alpha / Q000032:analysis; D053583:Interleukin-1beta / Q000032:analysis; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis; D009804:Odontoblasts / Q000473:pathology; D015675:Osteocalcin / Q000032:analysis*; D011671:Pulpitis / Q000145:classification / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
chemical_list: C111835:CCL2 protein, human; C508606:CXCL8 protein, human; D018932:Chemokine CCL2; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018836:Inflammation Mediators; D020381:Interleukin-17; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; D053645:Interleukin-2 Receptor alpha Subunit; D016209:Interleukin-8; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D015675:Osteocalcin; D005346:Fibroblast Growth Factors; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D003094:Collagen