title: Insulin resistance and beta cell function before and after sleeve gastrectomy in obese patients with impaired fasting glucose or type 2 diabetes.
abstract: BACKGROUND
  Pathophysiology of type 2 diabetes (T2D) includes insulin resistance (IR) and insufficient insulin secretion. Remission in obese patients can be achieved through surgically induced weight loss. Sleeve gastrectomy is a novel technique for the treatment of morbid obesity, and its effects on the metabolic syndrome and T2D have not yet been fully understood.
  
  
  METHODS
  From February 2008 to July 2010, sleeve gastrectomy as stand-alone treatment for severe or morbid obesity was performed in 23 patients with T2D or impaired fasting glucose (IFG). No postoperative complications occurred and patients were dismissed from hospital on day 2 after surgery. Body mass index (BMI), fasting blood glucose (FBG) and fasting insulin were determined before and up to 24 months after surgery. IR and beta cell function were calculated using the modified homeostasis model assessment (HOMA2).
  
  
  RESULTS
  BMI, FBG and fasting insulin improved significantly as early as 3 months after surgery. Threefold increased preoperative insulin resistance (3.05) decreased to near-normal values (1.14) during the same period. Interestingly, overall beta cell function diminished at 12 months of follow-up (79.6 %), in comparison with preoperative values (117.8 %). Patients with a markedly reduced preoperative beta cell function (<40 %) did not achieve a complete remission after surgery.
  
  
  CONCLUSIONS
  In obese patients with T2D and IFG, commonly characterized by an augmented beta cell function and an increased insulin resistance, sleeve gastrectomy induces remission through reduction of insulin resistance. Preoperative IR and beta cell function calculated by HOMA2 deserve further studies in patients undergoing metabolic surgery.
authors.affiliation: Obesity Center, Hospital de Santiago, EN 10, km 37, 2900-722, Setúbal, Portugal, h.c.a.e@sapo.pt.
authors.forename: Hans
authors.initials: H
authors.lastname: Eickhoff
authors.forename: Ana
authors.initials: A
authors.lastname: Guimarães
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Louro
authors.forename: Raquel M
authors.initials: RM
authors.lastname: Seiça
authors.forename: Francisco
authors.initials: F
authors.lastname: Castro E Sousa
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications*; D005215:Fasting / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy / Q000379:methods*; D018149:Glucose Intolerance / Q000097:blood / Q000150:complications*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000502:physiology*; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000150:complications* / Q000601:surgery; D011184:Postoperative Period; D057234:Preoperative Period; D012189:Retrospective Studies; D015431:Weight Loss / Q000502:physiology; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin