title: Correlation between salivary and serum markers of bone turnover in osteopenic rats.
abstract: BACKGROUND
  Previously, we measured bone alkaline phosphatase (b-ALP) and terminal C-telopeptide of collagen type I (CTX) in saliva. The present longitudinal experimental study sought to determine whether salivary concentrations of b-ALP and CTX have the same response as in serum samples under different conditions: normal, increased, and reduced bone remodeling.
  
  
  METHODS
  Thirty rats were ovariectomized (OVX) to induce osteopenia 60 days after surgery, and 10 rats were sham operated. Then, the rats were divided into four groups and treated as follows for 45 days: group 1 (G1) = SHAM + vehicle; group 2 (G2) = OVX + 8 microg olpadronate (OPD)/100 g of body weight; group 3 (G3) = OVX + 4 microg OPD/100 g of body weight; and group 4 (G4) = OVX + vehicle. Saliva and serum CTX and b-ALP were determined at 60 days (baseline) and at 75 days (T(75)). Lumbar spine and proximal tibia bone mineral density (BMD) was determined using dual-energy x-ray absorptiometry at baseline and at 105 days.
  
  
  RESULTS
  SHAM baseline and T(75) salivary b-ALP and CTX levels correlated with serum concentrations (P <0.01 and P <0.004, respectively). A correlation was observed between saliva and serum concentrations of b-ALP and CTX in OVX at baseline (P <0.0001 and P <0.004, respectively). Baseline salivary b-ALP and CTX levels were lower in SHAM animals compared to OVX groups (P <0.01). After treatment, T(75) saliva and serum CTX remained higher in G4 compared to G1 (P <0.05), was lower in G2 than in G1 (P <0.01) and G3 (P <0.01), and was similar in G1 and G3. Changes in BMD were the result of variations in salivary CTX levels due to OPD treatment (P <0.05).
  
  
  CONCLUSIONS
  Saliva determinations may prove to be practical and reliable for the detection of systemic signs of increased bone remodeling, particularly in cases involving pediatric, obese, and elderly patients, and in screening large populations. Moreover, saliva CTX may be one of the best candidate markers to detect the activity and severity of periodontal disease.
authors.affiliation: Oral and General Biochemistry Department, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Gretel G
authors.initials: GG
authors.lastname: Pellegrini
authors.forename: Chaves Macarena
authors.initials: CM
authors.lastname: Gonzales
authors.forename: Julia C
authors.initials: JC
authors.lastname: Somoza
authors.forename: Silvia M
authors.initials: SM
authors.lastname: Friedman
authors.forename: Susana N
authors.initials: SN
authors.lastname: Zeni
mesh_terms: D015502:Absorptiometry, Photon; D000469:Alkaline Phosphatase / Q000032:analysis* / Q000097:blood / Q000187:drug effects; D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000188:drug therapy / Q000378:metabolism*; D016723:Bone Remodeling / Q000187:drug effects / Q000502:physiology*; D024042:Collagen Type I / Q000032:analysis* / Q000097:blood / Q000187:drug effects; D004164:Diphosphonates / Q000008:administration & dosage / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D008159:Lumbar Vertebrae / Q000473:pathology; D010052:Ovariectomy; D010455:Peptides / Q000032:analysis* / Q000097:blood / Q000187:drug effects; D014677:Pharmaceutical Vehicles; D051381:Rats; D017208:Rats, Wistar; D012463:Saliva / Q000737:chemistry* / Q000187:drug effects; D013977:Tibia / Q000473:pathology; D013997:Time Factors
chemical_list: D015415:Biomarkers; D050071:Bone Density Conservation Agents; D024042:Collagen Type I; D004164:Diphosphonates; D010455:Peptides; D014677:Pharmaceutical Vehicles; C052929:collagen type I trimeric cross-linked peptide; C055774:olpadronic acid; D000469:Alkaline Phosphatase