NEW YORK (GenomeWeb) – Austrian researchers have uncovered short- and long-term metabolomics changes in blood samples from a subset of individuals who have undergone bariatric surgery for weight loss.
Using unbiased metabolomic profiling, the team tested blood samples from Roux-en-Y gastric bypass surgery patients in Austria and Switzerland, including two dozen individuals who had type 2 diabetes prior to surgery. As they reported in PLOS One, the investigators identified metabolomic shifts in samples collected before the bariatric surgery, just a few weeks post-surgery, and roughly a year later.
"Our analyses underline the need for a comprehensive analysis of short-term as well as long-term changes in order to gain a more complete picture of the metabolic changes induced by bariatric surgery," corresponding author Harald Sourij, an endocrinology and diabetology researcher at the Medical University of Graz, and his co-authors wrote.
Past studies have look at ways that Roux-en-Y gastric bypass surgery can impact everything from individuals' gut microbiome features to the epigenetic patterns present in their adipose tissue.
For the current analysis, Sourij and his colleagues used a combination of liquid chromatography and high resolution mass spectrometry to assess metabolites in 132 blood samples from 44 individuals who had Roux-en-Y gastric bypass surgery — a set that represented the pre-surgery period, the point that individuals were discharged from the hospital up to three weeks after surgery, and a follow up period one year later. The study participants were all older than 18, they noted, and 24 had type 2 diabetes before surgery.
The team's initial search led to 177 metabolic features that shifted at some stage after surgery. Of those, the group annotated 36 metabolites, including eight previously described markers of cardiovascular disease risk.
The study's authors noted that the overall metabolite changes detected during the duration of the study "are best described as trend patterns. Metabolites which display unidirectional trends of increasing or decreasing intensities are more likely to be of interest for future studies."
One quarter of the 36 metabolites consistently climbed or declined in plasma prevalence post-surgery, for example. When the team focused on metabolites with blood plasma shifts in individuals with the most dramatic weight loss results a year after surgery, it detected significant declines in metabolites such as the amino acids arginine and valine.
On the other hand, in blood samples from the nine individuals who had achieved type 2 diabetes remission a year after bariatric surgery, the researchers saw more substantial drops in levels of metabolites such as alanine, sarcosine, pyroglutamic acid, and leucyl-proline relative to samples from individuals whose type 2 diabetes persisted.
They noted that the individuals with diabetes remission also tended to be younger and had lived with diabetes for a shorter period of time, though their average weights were higher prior to bariatric surgery.