Conjugated bile acids associate with altered rates of glucose and lipid oxidation after Roux-en-Y gastric bypass.
BACKGROUND
Laparoscopic Roux-en-Y gastric bypass (RYGB) induces a more favorable metabolic profile than expected by weight loss alone. In this study, we investigated the effect of RYGB on serum bile acid levels and their relation to clinical outcomes.


METHODS
We included 30 obese patients who underwent RYGB (BMI = 46.1 ± 5.9 kg/m(2)). Clinical measurements and laboratory determinations were performed before surgery and 1 year after surgery. Fasting serum bile acids were measured by an enzymatic method and individual bile acids were quantified by HLPC-tandem mass spectrometry. Indirect calorimetry was performed to measure the rates of energy expenditure and substrate oxidation.


RESULTS
Fasting total serum bile acid levels increased twofold after RYGB (pre, 3.68 ± 2.03 vs. post, 7.06 ± 9.65 μmol/l, +92 %, p = 0.002). This increase in total bile acids was accompanied by a decrease in conjugated bile acids, which correlated with decreased glucose oxidation (r = 0.571, p = 0.002) and with increased lipid oxidation (r = -0.626, p = 0.0004). The change in taurine-conjugated bile acids correlated with altered DIO2 mRNA expression in adipose tissue (r = -0.498, p = 0.013) potentially linking bile acid conjugation to substrate oxidation through DIO2.


CONCLUSIONS
Fasting serum bile acid levels increase after RYGB. More specifically, changes in bile acid conjugation after RYGB associate with altered energy metabolism.
Department of Medicine, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland.
M
M
Simonen
N
N
Dali-Youcef
D
D
Kaminska
S
S
Venesmaa
P
P
Käkelä
M
M
Pääkkönen
M
M
Hallikainen
M
M
Kolehmainen
M
M
Uusitupa
L
L
Moilanen
M
M
Laakso
H
H
Gylling
M E
ME
Patti
J
J
Auwerx
Jussi
J
Pihlajamäki
D000273:Adipose Tissue / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D004734:Energy Metabolism; D005260:Female; D005387:Finland; D015390:Gastric Bypass; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery*; D016896:Treatment Outcome
D001647:Bile Acids and Salts; D015415:Biomarkers; D001786:Blood Glucose; D005947:Glucose