title: A comparison of a personal series of biliopancreatic diversion and literature data on gastric bypass help to explain the mechanisms of resolution of type 2 diabetes by the two operations.
abstract: BACKGROUND
  Roux-en-Y gastric bypass (RYGBP) and biliopancreatic diversion (BPD) are highly beneficial operations for type 2 diabetes mellitus (T2DM) in obese patients, leading to complete T2DM resolution in 75-90 and 97-99% of cases, respectively. In both RYGBP and BPD, the foregut is excluded from the food stream and the distal small bowel receives the food stimulation, while following BPD fat intestinal absorption is also extremely limited. This study was carried out to identify clinical features that could give insight on the different mechanisms of action on diabetes resolution.
  
  
  METHODS
  The files of 443 severely obese patients with T2DM undergoing BPD from May 1976 to May 2007 were examined, and the presence of T2DM (fasting serum glucose >125 mg/ml) at 1-2 months, at 1 year, at 10 years, and at > or =20 years following the operation was recorded.
  
  
  RESULTS
  The percentage of patients cured (fasting serum glucose reduced to < or =110 mg/dl, on free diet and with no therapy) was 74% at 1 month, 97% at 1 and 10 years, and 91% at > or =20 years, the 26% of uncured patients at 1 month being those with most severe preoperative T2DM.
  
  
  CONCLUSIONS
  As the early results after BPD resemble those reported after RYGBP, it can be hypothesized that the duodenal exclusion and the distal small bowel stimulation are the first mechanisms acting in BPD, immediately after the operation, that only subsequently the myocellular fat depletion, which cannot be immediate, takes over, and that the minimal fat absorption is the mechanism accounting for the long-term results of BPD.
authors.affiliation: Department of Surgery, University of Genoa Medical School-Azienda Ospedaliera, Universitaria San Martino, Largo Rosanna Benzi 8, Genoa, Italy. nicola.scopinaro@unige.it
authors.forename: Nicola
authors.initials: N
authors.lastname: Scopinaro
authors.forename: Francesco
authors.initials: F
authors.lastname: Papadia
authors.forename: Giovanni
authors.initials: G
authors.lastname: Camerini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Marinari
authors.forename: Dario
authors.initials: D
authors.lastname: Civalleri
authors.forename: Adami
authors.initials: A
authors.lastname: Gian Franco
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015904:Biliopancreatic Diversion; D015992:Body Mass Index; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism / Q000517:prevention & control*; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D008066:Lipolysis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000378:metabolism / Q000601:surgery*; D012189:Retrospective Studies; D055815:Young Adult