title: Quantitative analysis of MRP-8 in gingival crevicular fluid in periodontal health and disease using microbore HPLC.
abstract: BACKGROUND
  The protein components of GCF can be separated by reverse-phase microbore HPLC on a C18 column with detection on the basis of 214 nm absorbance. A single major symmetrical protein peak eluting with a retention time of 26 min (50% acetonitrile) was evident in gingival crevicular fluid (GCF) from periodontitis patients but not in healthy GCF. This protein was identified as human MRP-8 by N-terminal amino acid sequencing and liquid chromatography quadropole mass spectrometry.
  
  
  OBJECTIVE
  To quantify the amount of MRP-8 detectable in GCF from individual healthy, gingivitis and periodontitis affected sites and to study the relationship, if any, between the levels of this responsive protein and periodontal health and disease.
  
  
  METHODS
  GCF was sampled (30 s) from healthy, gingivitis, and periodontitis sites in peridontitis subjects (n=15) and from controls (n=5) with clinically healthy gingiva and no periodontitis. Purified MRP-8 was sequenced by Edmann degradation and the phenylthiohydantoin (PTH) amino acid yield determined (by comparison of peak area with external PTH amino acid standards). This value was subsequently used to calculate the relative amount of protein in the peak eluting with a retention time of 26.0 min (MRP-8) in individual GCF chromatograms.
  
  
  RESULTS
  Higher levels of MRP-8 were detected in inflammatory sites: periodontitis 457.0 (281.0) ng; gingivitis 413.5 (394.5) ng compared with periodontally healthy sites in diseased subjects 14.6 (14.3) ng and in controls 18.6 (18.5) ng, p=0.003. There was at least 20-fold more MRP-8 in the inflammatory compared with the healthy sites studied.
  
  
  CONCLUSIONS
  The preliminary data indicate that MRP-8 is present in GCF, with significantly greater amounts present at diseased than healthy sites. A systematic study of the relationship of this protein to periodontal disease could prove useful in further clarifying whether MRP-8 could be a reliable GCF biomarker of gingivitis and periodontitis.
authors.affiliation: School of Dentistry, Queen's University, Belfast, Northern Ireland, UK.
authors.forename: F T
authors.initials: FT
authors.lastname: Lundy
authors.forename: R
authors.initials: R
authors.lastname: Chalk
authors.forename: P J
authors.initials: PJ
authors.lastname: Lamey
authors.forename: C
authors.initials: C
authors.lastname: Shaw
authors.forename: G J
authors.initials: GJ
authors.lastname: Linden
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000943:Antigens, Differentiation / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D002135:Calcium-Binding Proteins / Q000032:analysis*; D040501:Calgranulin A; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D005883:Gingival Crevicular Fluid / Q000737:chemistry* / Q000276:immunology; D005891:Gingivitis / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008297:Male; D008970:Molecular Weight; D010518:Periodontitis / Q000276:immunology / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D000943:Antigens, Differentiation; D015415:Biomarkers; D002135:Calcium-Binding Proteins; D040501:Calgranulin A