title: Improved insulin sensitivity after gastric bypass correlates with decreased total body fat, but not with changes in free fatty acids.
abstract: BACKGROUND
  Increased plasma free fatty acids (FFAs) are considered one of the key elements in the pathogenesis of insulin resistance (IR) and type 2 diabetes (T2DM). We hypothesize that, in diabetic patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB), a postoperative decrease in FFA will correlate with improved insulin sensitivity (Si).
  
  
  METHODS
  A total of 30 obese [body mass index ((BMI) >35 kg/m(2)] patients with a diagnosis of T2DM were studied preoperatively and 12 months after LRYGB in a prospective cohort study. Collected data included intravenous glucose tolerance test (IVGTT), total body composition by dual-energy X-ray absorptiometry and plasma levels of FFA. Si analysis from the IVGTT was estimated from minimal model analysis. Pre- and postoperative variables were compared using a paired sample t test. Relationships between changes in variables were determined with Pearson's correlation test.
  
  
  RESULTS
  Twelve months after LRYGB the study population showed a significant decrease in BMI (p = 0.001), FFA (p = 0.03), and total body fat (p = 0.03), with an increase in Si (p = 0.001). Postoperative changes in Si significantly correlated (Pearson's r = -0.53, p = 0.01) with change in total body fat, but not with changes in plasma FFA (Pearson's r = -0.22, p = 0.31).
  
  
  CONCLUSIONS
  Our study challenges the notion that IR is mediated to a significant degree by changes in plasma FFA concentration. Instead, changes in adiposity and consequently changes in adipokine release can be the key players in determining remission of T2DM after LRYGB.
authors: Department of Surgery, Duke University; Durham, NC, USA.
authors: Alessandro
authors: A
authors: Mor
authors: Department of Surgery, Duke University; Durham, NC, USA.
authors: Lawrence
authors: L
authors: Tabone
authors: Department of Surgery, Duke University; Durham, NC, USA.
authors: Philip
authors: P
authors: Omotosho
authors: Department of Surgery, Duke University; Durham, NC, USA.
authors: Alfonso
authors: A
authors: Torquati
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000150:complications / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D005230:Fatty Acids, Nonesterified; D007328:Insulin