title: Bone turnover markers in serum and periodontal microenvironments.
abstract: BACKGROUND
  Periodontitis is characterized by altered bone turnover, but local measurements are difficult.
  
  
  OBJECTIVE
  The objective of this study was to develop a method to measure multiple markers of bone turnover from single samples collected at various bone surfaces of the periodontium, and to test the ratios of these markers against more traditional serum and gingival crevicular fluid (GCF) samples.
  
  
  METHODS
  Fourteen subjects with untreated periodontitis were recruited for sampling serum, GCF (from sites > or = 5 mm probing depth that bled on probing) and washes of periodontal bone surfaces (adjacent interproximal, vestibular cortical and trabecular bone) with a novel irrigating device. All samples were analyzed for osteocalcin (OC, bone turnover marker; RIA), cross-linked N-telopeptide of type I collagen (NTx, bone resorption marker; ELISA) and albumin (Alb, serum protein; ELISA). Results were reported as ratios: OC/NTx to determine relative bone turnover, and OC/Alb or NTx/Alb to determine local OC or NTx production.
  
  
  RESULTS
  The OC/NTx ratio was significantly higher (p < or = 0.05) in serum vs. GCF (OC undetectable), interproximal bone and cortical vestibular bone, but significantly lower than in trabecular vestibular bone. The OC/Alb ratio for serum was also statistically lower than for vestibular trabecular bone. The NTx/Alb ratio for serum was statistically lower than for GCF and all the bone wash test sites. The results indicated considerable local production of both OC and NTx.
  
  
  CONCLUSIONS
  This system demonstrated that multiple markers of bone turnover can be harvested by irrigation from periodontal bone microenvironments. Bone turnover profiles from periodontal bone surfaces and GCF differed from systemic bone turnover profiles (serum) and may be valuable in tracking site-specific responses to disease or treatment.
authors.affiliation: Department of Surgical Specialties, University of Nebraska Medical Center, College of Dentistry, Lincoln, Department of Biometry, University of Nebraska, Lincoln, NE 68583-0757, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Wilson
authors.forename: M J
authors.initials: MJ
authors.lastname: Schmid
authors.forename: D B
authors.initials: DB
authors.lastname: Marx
authors.forename: R A
authors.initials: RA
authors.lastname: Reinhardt
mesh_terms: D000328:Adult; D000368:Aged; D000418:Albumins / Q000032:analysis; D000539:Alveolar Process / Q000378:metabolism*; D000704:Analysis of Variance; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D003094:Collagen / Q000032:analysis* / Q000097:blood; D024042:Collagen Type I; D005260:Female; D005883:Gingival Crevicular Fluid / Q000737:chemistry; D005884:Gingival Hemorrhage / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000032:analysis* / Q000097:blood; D010455:Peptides / Q000032:analysis* / Q000097:blood; D010514:Periodontal Pocket / Q000378:metabolism; D010518:Periodontitis / Q000097:blood / Q000378:metabolism*; D012709:Serum Albumin / Q000032:analysis; D007507:Therapeutic Irrigation / Q000295:instrumentation
chemical_list: D000418:Albumins; D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; D012709:Serum Albumin; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D003094:Collagen