title: Circulating concentrations of high-molecular-weight adiponectin are increased following Roux-en-Y gastric bypass surgery.
abstract: OBJECTIVE
  In addition to weight loss, bariatric surgery for severe obesity dramatically alleviates insulin resistance. In this study, we investigated whether circulating concentrations of the high-molecular-weight (HMW) form of adiponectin are increased following gastric bypass surgery. The HMW form is implicated as the multimer responsible for adiponectin's hepatic insulin-sensitising actions.
  
  
  METHODS
  We studied 19 women who were undergoing Roux-en-Y gastric bypass surgery. Studies were conducted prior to, and 1 and 12 months after surgery.
  
  
  RESULTS
  One month after surgery, total plasma adiponectin concentrations were unchanged. Nevertheless, increases in both HMW (by 40+/-15%, p=0.006) and the proportion of adiponectin in the HMW form (from 40+/-2 to 50+/-2%, p<0.0001) were observed. At 12 months, total and HMW adiponectin concentrations were increased by 58+/-8% and 118+/-21%, respectively (both p<0.001). The majority (80%) of the increase of total adiponectin was due to an increase of the HMW form. After adjustment for covariates, increases of HMW and total adiponectin at 12 months were correlated with the decrease of fat mass (HMW, p=0.0076; total, p=0.0302). In subjects with improved insulin sensitivity at 12 months after surgery (n=18), the increase of HMW, but not that of total adiponectin, predicted the relative decrease of insulin resistance (HMW: p=0.0044; total: p=0.0775, after adjustment for covariates).
  
  
  CONCLUSIONS
  These data suggest that the reduction of fat mass following gastric bypass surgery is an important determinant of the increase of HMW adiponectin concentrations, which in turn is associated with and may contribute to the resulting improvement of insulin sensitivity.
authors.affiliation: Department of Nutrition, College of Agricultural and Environmental Sciences, University of California, Davis, CA 95616-5270, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Swarbrick
authors.forename: I T
authors.initials: IT
authors.lastname: Austrheim-Smith
authors.forename: K L
authors.initials: KL
authors.lastname: Stanhope
authors.forename: M D
authors.initials: MD
authors.lastname: Van Loan
authors.forename: M R
authors.initials: MR
authors.lastname: Ali
authors.forename: B M
authors.initials: BM
authors.lastname: Wolfe
authors.forename: P J
authors.initials: PJ
authors.lastname: Havel
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D000713:Anastomosis, Roux-en-Y; D015992:Body Mass Index; D049628:Body Size; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass; D006801:Humans; D008875:Middle Aged; D008970:Molecular Weight; D009767:Obesity, Morbid / Q000097:blood / Q000601:surgery
chemical_list: D052242:Adiponectin