Protein and Glucose Absorption and Gastrointestinal Hormone Secretion Differ between Roux-en-Y Gastric Bypass and Sleeve Gastrectomy
Authors: SVANE MARIA S. , BOJSEN-MOLLER KIRSTINE N. , MARTINUSSEN CHRISTOFFER , DIRKSEN CARSTEN , REITELSEDER SØREN , HOLM LARS , KRISTIANSEN VIGGO B. , HALL GERRIT VAN , HOLST JENS J. , MADSBAD STEN 
Published: June 2018

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) induce comparable weight loss and improvements in glycemic control despite marked differences in gastrointestinal rearrangements. We hypothesized that absorption rates of oral glucose and protein derived amino acids (AA) were accelerated after both procedures resulting in comparable gut hormone responses. 12 SG and 12 RYGB operated and 12 control (C) subjects carefully matched on BMI, age, sex and post-operative weight loss received primed-continuous infusions of stable isotopes of glucose, glycerol, phenylalanine (phe), tyrosine and urea combined with a 6-hour mixed meal test (400 kcal, 50E% carb, 35E% fat, 15E% protein) containing a glucose isotope and intrinsically phe labelled casein. Peak rate of appearance (Ra) of oral glucose was higher after RYGB and SG compared with C (RYGB 36±1 µmol/kg FFM/min, SG 27±1, C 22±1; p&lt;0.for all comparisons) and peak Ra of phe originating from meal protein was higher after RYGB but similar in SG and C (RYGB 0.33±0.04, SG 0.17±0.02, C 0.13 ±0.01 p&lt;0.01 for RYGB vs. both SG and C). Oral recovery of ingested glucose and phe as well as net protein synthesis were clearly enhanced within the first postprandial hour after RYGB, whereas total net protein balance and oral recovery did not differ between groups. Urea turnover was equal between groups. The rapid absorption of glucose and phe was associated with larger but more transient excursions of plasma glucose and AAs followed by increased lactate formation and higher secretion of GLP-1, insulin and PYY, exclusively after RYGB. Ghrelin concentration was lower after SG. Postprandial glucose and protein metabolism and gastro-entero-pancreatic hormone secretion clearly differ after RYGB and SG, with accelerated absorption of glucose and casein after RYGB, whereas casein uptake after SG resembled controls. Hence different mechanisms may underlie the improved glycemic control and weight loss after RYGB and SG.

Disclosure
M.S. Svane: None. K.N. Bojsen-Moller: None. C. Martinussen: None. C. Dirksen: None. S. Reitelseder: None. L. Holm: None. V.B. Kristiansen: None. G. van Hall: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. Board Member; Self; Zealand Pharma A/S. Speaker's Bureau; Self; Merck Sharp & Dohme Corp., AstraZeneca. Research Support; Self; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Self; Antag Therapeutics. Other Relationship; Spouse/Partner; Antag Therapeutics. S. Madsbad: Advisory Panel; Self; AstraZeneca. Speaker's Bureau; Self; AstraZeneca. Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Speaker's Bureau; Self; Eli Lilly and Company, Eli Lilly and Company. Advisory Panel; Self; Merck Sharp & Dohme Corp., Sanofi-Aventis, Novo Nordisk A/S. Speaker's Bureau; Self; Novo Nordisk A/S. Research Support; Self; Novo Nordisk A/S.