title: Circulating sclerostin levels and bone turnover in type 1 and type 2 diabetes.
abstract: BACKGROUND
  Previous observations showed a condition of low bone turnover and decreased osteoblast activity in both type 1 and 2 diabetes mellitus (DM1 and DM2). Sclerostin is a secreted Wnt antagonist produced by osteocytes that regulates osteoblast activity and thus bone turnover. Its levels increase with age and are regulated by PTH.
  
  
  OBJECTIVE
  The aim of the present study was to evaluate circulating sclerostin levels in patients with DM1 or DM2 with normal renal function and to analyze its relationship with PTH, 25-hydroxyvitamin D, and bone turnover markers. DESIGN, AND SETTING: This was a cross-sectional study conducted at a clinical research center.
  
  
  METHODS
  Forty DM2 and 43 DM1 patients were studied and compared with a reference control group (n = 83).
  
  
  RESULTS
  In the overall cohort, sclerostin levels were higher in males than in females and significantly increased with age in both genders. The positive correlation between sclerostin and age was maintained in DM1 but not in DM2 patients. Moreover, sclerostin levels were higher in DM2 than in controls or DM1 patients, and this difference persisted when adjustments were made for age and body mass index. Consistent with previous clinical and experimental observations, sclerostin was negatively associated with PTH in nondiabetic patients (r = -0.30; P < 0.01), independently of age and gender. Conversely, an opposite but nonsignificant trend between PTH and sclerostin was observed in both DM1 (r = 0.26; P = 0.09) and DM2 (r = 0.32; P = 0.07) cohorts.
  
  
  CONCLUSIONS
  These findings suggest that sclerostin is increased in DM2. Moreover, the transcriptional suppression of sclerostin production by PTH might be impaired in both DM1 and DM2.
authors.affiliation: Department of Internal Medicine Endocrine-Metabolic Sciences, and Biochemistry, University of Siena, Viale Bracci 1, 53100 Siena, Italy. gennari@unisi.it
authors.forename: Luigi
authors.initials: L
authors.lastname: Gennari
authors.forename: Daniela
authors.initials: D
authors.lastname: Merlotti
authors.forename: Roberto
authors.initials: R
authors.lastname: Valenti
authors.forename: Elena
authors.initials: E
authors.lastname: Ceccarelli
authors.forename: Martina
authors.initials: M
authors.lastname: Ruvio
authors.forename: Maria G
authors.initials: MG
authors.lastname: Pietrini
authors.forename: Cosimo
authors.initials: C
authors.lastname: Capodarca
authors.forename: Maria Beatrice
authors.initials: MB
authors.lastname: Franci
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Campagna
authors.forename: Anna
authors.initials: A
authors.lastname: Calabrò
authors.forename: Dorica
authors.initials: D
authors.lastname: Cataldo
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Stolakis
authors.forename: Francesco
authors.initials: F
authors.lastname: Dotta
authors.forename: Ranuccio
authors.initials: R
authors.lastname: Nuti
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000367:Age Factors; D000368:Aged; D019485:Bone Morphogenetic Proteins / Q000097:blood*; D016723:Bone Remodeling / Q000502:physiology*; D001842:Bone and Bones / Q000378:metabolism*; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; D010281:Parathyroid Hormone; C422903:SOST protein, human; D014807:Vitamin D; C104450:25-hydroxyvitamin D