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Nils Wierup

Nils Wierup

Senior lecturer

Nils Wierup

The impact of Roux-en-Y gastric bypass surgery on normal metabolism in a porcine model


  • Andreas Lindqvist
  • Mikael Ekelund
  • Eliana Garcia-Vaz
  • Marcus Ståhlman
  • Stefan Pierzynowski
  • Maria F. Gomez
  • Jens F Rehfeld
  • Leif Groop
  • Jan Hedenbro
  • Nils Wierup
  • Peter Spégel

Summary, in English

Background A growing body of literature on Roux-en-Y gastric bypass surgery (RYGB) has generated inconclusive results on the mechanism underlying the beneficial effects on weight loss and glycaemia, partially due to the problems of designing clinical studies with the appropriate controls. Moreover, RYGB is only performed in obese individuals, in whom metabolism is perturbed and not completely understood. Methods In an attempt to isolate the effects of RYGB and its effects on normal metabolism, we investigated the effect of RYGB in lean pigs, using sham-operated pair-fed pigs as controls. Two weeks post-surgery, pigs were subjected to an intravenous glucose tolerance test (IVGTT) and circulating metabolites, hormones and lipids measured. Bile acid composition was profiled after extraction from blood, faeces and the gallbladder. Results A similar weight development in both groups of pigs validated our experimental model. Despite similar changes in fasting insulin, RYGB-pigs had lower fasting glucose levels. During an IVGTT RYGB-pigs had higher insulin and lower glucose levels. VLDL and IDL were lower in RYGB- than in sham-pigs. RYGB-pigs had increased levels of most amino acids, including branched-chain amino acids, but these were more efficiently suppressed by glucose. Levels of bile acids in the gallbladder were higher, whereas plasma and faecal bile acid levels were lower in RYGB- than in sham-pigs. Conclusion In a lean model RYGB caused lower plasma lipid and bile acid levels, which were compensated for by increased plasma amino acids, suggesting a switch from lipid to protein metabolism during fasting in the immediate postoperative period.


  • Neuroendocrine Cell Biology
  • Surgery (Lund)
  • Diabetic Complications
  • Functional zoology
  • Genomics, Diabetes and Endocrinology
  • Centre for Analysis and Synthesis
  • EXODIAB: Excellence of Diabetes Research in Sweden

Publishing year










Document type

Journal article


Public Library of Science (PLoS)


  • Endocrinology and Diabetes



Research group

  • Neuroendocrine Cell Biology
  • Diabetic Complications
  • Genomics, Diabetes and Endocrinology


  • ISSN: 1932-6203