title: Plasma osteopontin increases after bariatric surgery and correlates with markers of bone turnover but not with insulin resistance.
abstract: BACKGROUND
  Osteopontin (OPN) is a multifunctional protein involved in bone metabolism, cardiovascular disease, diabetes, and obesity. OPN levels are elevated in the plasma and adipose tissue of obese subjects, and are decreased with diet-induced weight loss.
  
  
  OBJECTIVE
  We investigated the effect of bariatric surgery on plasma OPN concentrations in morbidly obese patients.
  
  
  METHODS
  The study was performed at a university hospital.
  
  
  METHODS
  We investigated 40 obese patients aged 43.1 +/- 1.8 yr, scheduled to undergo bariatric surgery. Roux-en-Y gastric bypass (RYGB) was performed in 30 subjects (27 females, three males), and laparoscopic adjustable gastric banding (LAGB) in 10 subjects (eight females, two males).
  
  
  METHODS
  All patients were studied before and 1 yr (10.3-14.8 months) after the intervention.
  
  
  METHODS
  OPN, leptin, C-reactive protein, insulin, the homeostatic model assessment insulin resistance index, calcium, 25-hydroxyvitamin D, C telopeptide, and osteocalcin were determined.
  
  
  RESULTS
  Both bariatric procedures significantly reduced body weight, body mass index, insulin, leptin, and C-reactive protein 1 yr after surgery. Plasma OPN increased from 31.4 +/- 3.8 to 52.8 +/- 3.7 ng/ml after RYGB (P < 0.001) and from 29.8 +/- 6.9 to 46.4 +/- 10.6 ng/ml after LAGB (P = 0.042). Preoperative OPN correlated with age, insulin, the homeostatic model assessment insulin resistance index, and postoperative OPN. Postoperative OPN correlated with C telopeptide and osteocalcin.
  
  
  CONCLUSIONS
  One year after RYGB and LAGB, plasma OPN levels significantly increased and correlated with biomarkers of bone turnover. Unlike other proinflammatory cytokines, OPN does not normalize but increases further after bariatric surgery.
authors.affiliation: Department of Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, Austria. michaela.riedl@meduniwien.ac.at
authors.forename: Michaela
authors.initials: M
authors.lastname: Riedl
authors.forename: Greisa
authors.initials: G
authors.lastname: Vila
authors.forename: Christina
authors.initials: C
authors.lastname: Maier
authors.forename: Ammon
authors.initials: A
authors.lastname: Handisurya
authors.forename: Soheila
authors.initials: S
authors.lastname: Shakeri-Manesch
authors.forename: Gerhard
authors.initials: G
authors.lastname: Prager
authors.forename: Oswald
authors.initials: O
authors.lastname: Wagner
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kautzky-Willer
authors.forename: Bernhard
authors.initials: B
authors.lastname: Ludvik
authors.forename: Martin
authors.initials: M
authors.lastname: Clodi
authors.forename: Anton
authors.initials: A
authors.lastname: Luger
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000379:methods; D015415:Biomarkers / Q000097:blood; D016723:Bone Remodeling / Q000502:physiology*; D024042:Collagen Type I / Q000097:blood; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000601:surgery; D015675:Osteocalcin / Q000097:blood; D053495:Osteopontin / Q000097:blood*; D010455:Peptides / Q000097:blood; D013997:Time Factors; D015854:Up-Regulation; D015431:Weight Loss / Q000502:physiology
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D053495:Osteopontin