title: Decreased salivary matrix metalloproteinase-8 reflecting a defensive potential in juvenile parotitis.
abstract: OBJECTIVE
  Matrix metalloproteinases MMP-2 and MMP-9 have been associated with juvenile parotitis. However, the role of MMP-8 has not been addressed previously. This work focuses on salivary MMP-8 and -9 levels in juvenile parotitis.
  
  
  METHODS
  During a five-year period at Helsinki University Hospital, a tertiary care hospital, 41 patients aged 17 or under, were identified as having parotitis; from 36 of these patients, saliva samples were collected for MMP-8 IFMA (time-resolved immunofluorometric assay) analyses. Control saliva samples were collected from 34 age- and gender-matched children admitted for an elective surgery who had no history of parotitis. For comparison, salivary levels of MMP-9, tissue inhibitor of matrix metalloproteinase (TIMP-1), MMP-8/TIMP-1 ratio, human neutrophil elastase (HNE), and myeloperoxidase (MPO) were analyzed by ELISA. Additionally, salivary MMP-8 levels were compared to historical saliva samples from 18 adult gingivitis patients as well as to 10 healthy adult controls.
  
  
  RESULTS
  The median (25%, 75% percentile) MMP-8 concentration in saliva of parotitis patients was significantly lower than MMP-8 concentration in saliva of their controls [50.4ng/ml (37.5, 72.9) vs. 148.5ng/ml (101.2, 178.5) p<0.0001] and lower than in patients with gingivitis [347.9ng/ml (242.6, 383.2) p<0.0001] or healthy adult controls [257.2ng/ml (164.9, 320.7) p<0.0001]. The MMP-8/TIMP-1 ratio was lower than in controls [0.13 (0.05-0.02) vs. 0.3 (0.17-0.46) p<0.0001]. The median MMP-9 concentration in saliva of parotitis patients was significantly higher than in controls [143.9ng/m (68.8-189.0) vs. 34.9ng/ml (16.3-87.6) p<0.0001]. Neither HNE, MPO, nor TIMP-1 alone separated the patients from the control groups.
  
  
  CONCLUSIONS
  MMP-9 was up-regulated in juvenile parotitis saliva, suggesting that MMP-9 may play a destructive role in juvenile parotitis, as others have suggested. The present novel findings reveal a decreased salivary MMP-8 concentration, suggesting that MMP-8 may reflect in juvenile parotitis down-regulated or anti-inflammatory immune characteristics.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; Department of Clinical Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland. Electronic address: riitta.t.saarinen@hus.fi.
authors.forename: Riitta
authors.initials: R
authors.lastname: Saarinen
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; Department of Clinical Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Anne
authors.initials: A
authors.lastname: Pitkäranta
authors.affiliation: Department of Clinical Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Kaija-Leena
authors.initials: KL
authors.lastname: Kolho
authors.affiliation: Department of Oral and Maxillofacial Diseases, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Taina
authors.initials: T
authors.lastname: Tervahartiala
authors.affiliation: Department of Clinical Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; Department of Oral and Maxillofacial Diseases, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Timo
authors.initials: T
authors.lastname: Sorsa
authors.affiliation: Department of Clinical Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland; Division of Infectious Diseases, Inflammation Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Anneli
authors.initials: A
authors.lastname: Lauhio
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005891:Gingivitis / Q000201:enzymology; D006801:Humans; D019272:Leukocyte Elastase / Q000378:metabolism; D008297:Male; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D010309:Parotitis / Q000201:enzymology*; D009195:Peroxidase / Q000378:metabolism; D012463:Saliva / Q000378:metabolism*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
chemical_list: C560822:TIMP1 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D009195:Peroxidase; D019272:Leukocyte Elastase; D020784:Matrix Metalloproteinase 8; D020780:Matrix Metalloproteinase 9
keywords: MMP-8; MMP-9; Matrix metalloproteinase; Parotitis