Circulating Amino Acid Changes Three Years After Bariatric Surgery.

Background And Objective: Studies using metabolomics to study bariatric surgery have shown that amino acids are one of the most changed groups of metabolites after the intervention. However, the surgery-related variation in individual amino acids, as well as the long-term impact and the differences between the types of surgeries, have been poorly studied. The aim of this study was to investigate the changes in circulating amino acids after three types of bariatric surgery up to 36 months after the intervention.

Methods: We studied 63 participants diagnosed with T2D at baseline, who received either a sleeve gastrectomy, a Roux-en-Y gastric bypass or a biliopancreatic diversion with duodenal switch. We measured the concentrations of 16 circulating amino acids in fasting plasma before the surgery as well as after 4, 12, 24 and 36 months via liquid chromatography coupled with mass spectrometry (LC-MS/MS).

Results: Eleven circulating amino acids were significantly modified by bariatric surgery. Glutamate, leucine and isoleucine showed the greatest decrease. Most of the changes in circulating amino acids occurred within 1 year of the operations. Only one measured plasmatic amino acid (threonine) had a significantly different change pattern according to surgery types. In repeated-measure correlations, changes in circulating amino acids were significantly associated with changes in adiposity and metabolic markers.

Conclusions: Bariatric surgery changes the levels of most circulating amino acids, and the effect occurs in the short term without major differences between surgery types. The mechanisms explaining these changes are not elucidated but likely include modifications in amino acid metabolism.