title: Improvement in insulin sensitivity and β-cell function following ileal interposition with sleeve gastrectomy in type 2 diabetic patients: potential mechanisms.
abstract: BACKGROUND
  Bariatric surgery in morbidly obese type 2 diabetic (T2DM) patients is associated with high rates of diabetes remission. We investigated the mechanisms of the anti-diabetic effect of the laparoscopic ileal interposition with sleeve gastrectomy (LII-SG) in normal weight (NW), overweight (OW) and obese (OB) T2DM patients.
  
  
  METHODS
  Ninety-four patients (aged 54 ± 8 years) with long-standing (median 10 years), treated diabetes (median HbA(1c) = 8.6%), who were NW (15), OW (64) or OB (15) based on BMI, underwent LII-SG. Insulin sensitivity and parameters of ß-cell function were measured from an Oral Glycaemic Tolerance Test pre- and post-operatively.
  
  
  RESULTS
  At a median of 13.4 months post-operatively, weight loss averaged 9.4 ± 1.3, 16.8 ± 0.8 and 23.2 ± 1.7 kg in NW, OW and OB subjects, respectively (p < 0.0001). Insulin sensitivity was fully restored (395 [108] vs 208 [99] ml min⁻¹ m⁻²), fasting insulin secretion rate decreased (68 [52] vs 146 [120] pmol min⁻¹ m⁻²) and total insulin output increased (52 [26] vs 39 [28] nmol m⁻², all p ≤ 0.001). ß-cell glucose sensitivity doubled (37 [33] vs 18 [24] mol min⁻¹ m⁻² mM⁻¹, p < 0.0001). The only parameter predicting remission of diabetes was a lower baseline insulin sensitivity (p = 0.005).
  
  
  CONCLUSIONS
  LII-SG induced changes on T2DM by mechanisms in part distinct from weight loss, principally involving restoration of insulin sensitivity and improvement of ß-cell function.
authors.affiliation: Department of Surgery, Hospital de Especialidades, Goiânia, Goiás, Brazil. adepaula@uol.com.br
authors.forename: Aureo Ludovico
authors.initials: AL
authors.lastname: De Paula
authors.forename: Alessandro R
authors.initials: AR
authors.lastname: Stival
authors.forename: Alfredo
authors.initials: A
authors.lastname: Halpern
authors.forename: Carolina C L
authors.initials: CC
authors.lastname: DePaula
authors.forename: Andrea
authors.initials: A
authors.lastname: Mari
authors.forename: Elza
authors.initials: E
authors.lastname: Muscelli
authors.forename: Sergio
authors.initials: S
authors.lastname: Vencio
authors.forename: Ele
authors.initials: E
authors.lastname: Ferrannini
mesh_terms: D050110:Bariatric Surgery / Q000379:methods; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D005743:Gastrectomy; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007082:Ileum / Q000601:surgery*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000503:physiopathology / Q000601:surgery; D050177:Overweight / Q000097:blood / Q000503:physiopathology / Q000601:surgery
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human