Metabolic alterations in plasma after laparoscopic sleeve gastrectomy

Characterization of the plasma metabolome and lipidome in response to sleeve gastrectomy and gastric bypass surgeries reveals molecular patterns of surgical weight loss

OBJECTIVES

Bariatric surgery improves metabolic health, but the underlying mechanisms are not fully understood. We analyzed the effects of two types of bariatric surgery, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), on the plasma metabolome and lipidome.

METHODS

We characterized the plasma metabolome (1268 metabolites) and lipidome (953 lipids) pre-operatively and at 3 and 12 months post-operatively in 104 obese adults who were previously recruited to a prospective cohort of bariatric surgery. The metabolomic and lipidomic responses to bariatric surgery over time were analyzed using multivariable linear mixed-effects models.

RESULTS

There were significant changes in multiple metabolites and lipids, including rapid early changes in amino acid and peptide metabolites, including decreases in branched-chain amino acids (BCAAs), aromatic AAs, alanine and aspartate, and increases in glycine, serine, arginine and citrulline. There were also significant decreases in many triglyceride species, with increases in phosphatidylcholines and phosphatidylethanolamines. There were significant changes in metabolites related to energy metabolism that were apparent only after 12 months. We observed differences by bariatric surgery type in the changes in a small number of primary and secondary bile acids, including glycohyocholate and glyco-beta-muricholate.

CONCLUSIONS

Our findings highlight the comprehensive changes in metabolites and lipids that occur over the 12 months following bariatric surgery. While both SG and RYGB caused profound changes in the metabolome and lipidome, RYGB was characterized by greater increases in bile acids following surgery.

Impact of Bariatric Surgery on Circulating Metabolites and Cognitive Performance

INTRODUCTION

Bariatric surgery is an effective intervention to reduce obesity and improve associated comorbidities. However, its effects on cognitive function are still the subject of debate. Given that the bioavailability of circulating metabolites can influence brain metabolism and cognitive performance, we aimed to assess the effects of bariatric surgery on plasma metabolic profiles and cognitive performance.

METHODS

We recruited 26 women undergoing gastric bypass surgery. We conducted anthropometric assessments and collected plasma samples for metabolomic analysis. A set of 4 cognitive tests were used to evaluate cognitive performance. Participants were reevaluated 1 year post-surgery.

RESULTS

After surgery, attention capacity and executive function were improved, while immediate memory had deteriorated. Regarding metabolic profile, reduction of beta-tocopherol and increase of serine, glutamic acid, butanoic acid, and glycolic acid were observed. To better understand the relationship between cognitive function and metabolites, a cluster analysis was conducted to identify more homogeneous subgroups based on the cognitive performance. We identified cluster 1, which did not show changes in cognitive performance after surgery, and cluster 2, which showed improved attention and executive function, but reduced performance in the immediate memory test. Thus, cluster 2 was more homogeneous group that replicated the results of non-clustered subjects. Analysis of the metabolic profile of cluster 2 confirmed serine, glutamic acid, and glycolic acid as potential metabolites associated with cognitive performance.

CONCLUSIONS

Metabolites identified in this study have potential for biomarkers and alternative therapeutic target to prevent obesity-related cognitive decline.

KEY POINTS

• Attention capacity and executive function were improved 12 months post bariatric surgery. • Immediate memory was worsened 12 months post bariatric surgery. • Serine, glutamic acid, and glycolic acid are potential metabolites linked to the alteration of cognitive performance.

The early effects of sleeve gastrectomy on postprandial chylomicron triglycerides during the progression of type 2 diabetes

BACKGROUND

It remains unclear whether early sleeve gastrectomy (SG) improves postprandial very-low-density lipoprotein (VLDL) as well as chylomicron triglycerides (TGs) in a weight-independent manner in patients with or without type 2 diabetes (DM). Herein we investigated the early effects of SG on postprandial VLDL and chylomicron kinetics.

METHODS

A liquid meal test was performed before and after 1 week of SG. The plasma was collected for postprandial triglyceride-rich lipoprotein kinetics analyses, including VLDLs and chylomicrons, isolated by high-speed ultracentrifugation. Lipidomics and metabolomics were used to profile lipid and metabolite compositions of plasma and postprandial chylomicrons. De novo fatty acid synthesis in intestinal epithelial cells treated with chylomicron metabolites was examined using RT-PCR, immunoblotting, and free fatty acid measurement.

RESULTS

We found that patients with DM had markedly higher VLDL TGs than patients without DM, and such an increase was still retained after SG. In contrast, SG significantly decreased postprandial chylomicron TGs, but surprisingly, the degree of the reduction in patients with DM was less prominent than in patients without DM, confirmed by untargeted lipidomics analysis. Moreover, 5 unique metabolites potentially linked to de novo fatty acid synthesis from the pathway analysis were discovered by further metabolomic analysis of postprandial chylomicrons from patients with DM who underwent SG and verified by In vitro intestinal epithelial cell culture experiments.

CONCLUSIONS

SG in 1 week did not impact postprandial VLDL but decreased chylomicron TGs. Patients with DM keep higher postprandial chylomicron TG concentrations than patients without it after SG, potentially through some unique metabolites that increase intestinal fatty acid synthesis. These results implicate the timing for SG to reach lower intestinal fatty acid synthesis and postprandial chylomicron TG production is prior to the diagnosis of DM to potentially reduce cardiovascular risks.

Metabolomic analysis-identified 2-hydroxybutyric acid might be a key metabolite of severe preeclampsia

This study set out to determine the key metabolite changes underlying the pathophysiology of severe preeclampsia (PE) using metabolic analysis. We collected sera from 10 patients with severe PE and from 10 healthy pregnant women of the same trimester and analyzed them using liquid chromatography mass spectrometry. A total of 3,138 differential metabolites were screened, resulting in the identification of 124 differential metabolites. Kyoto encyclopedia of genes and genomes pathway analysis revealed that they were mainly enriched in the following metabolic pathways: central carbon metabolism in cancer; protein digestion and absorption; aminoacyl-transfer RNA biosynthesis; mineral absorption; alanine, aspartate, and glutamate metabolism; and prostate cancer. After analysis of 124 differential metabolites, 2-hydroxybutyric acid was found to be the most critical differential metabolite, and its use allowed the differentiation of women with severe PE from healthy pregnant women. In summary, our analysis revealed that 2-hydroxybutyric acid is a potential key metabolite for distinguishing severe PE from healthy controls and is also a marker for the early diagnosis of severe PE, thus allowing early intervention.

Metabolomic signatures after bariatric surgery - a systematic review

Metabolomics emerged as an important tool to gain insights on how the body responds to therapeutic interventions. Bariatric surgery is the most effective treatment for severe obesity and obesity-related co-morbidities. Our aim was to conduct a systematic review of the available data on metabolomics profiles that characterize patients submitted to different bariatric surgery procedures, which could be useful to predict clinical outcomes including weight loss and type 2 diabetes remission. For that, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - PRISMA guidelines were followed. Data from forty-seven original study reports addressing metabolomics profiles induced by bariatric surgery that met eligibility criteria were compiled and summarized. Amino acids, lipids, energy-related and gut microbiota-related were the metabolite classes most influenced by bariatric surgery. Among these, higher pre-operative levels of specific lipids including phospholipids, long-chain fatty acids and bile acids were associated with post-operative T2D remission. As conclusion, metabolite profiling could become a useful tool to predict long term response to different bariatric surgery procedures, allowing more personalized interventions and improved healthcare resources allocation.

Liver Injury and Acute Liver Failure After Bariatric Surgery: An Overview of Potential Injury Mechanisms

The obesity epidemic has caused a surge in the use of bariatric surgery. Although surgery-induced weight loss is an effective treatment of nonalcoholic fatty liver disease, it may precipitate severe hepatic complications under certain circumstances. Acute liver injury (ALI) and acute liver failure (ALF) following bariatric surgery have been reported in several case series. Although rare, ALI and ALF tend to emerge several months after bariatric surgery. If so, it can result in prolonged hospitalization, may necessitate liver transplantation, and in some cases prove fatal. However, little is known about the risk factors for developing ALI or ALF after bariatric surgery and the mechanisms of liver damage in this context are poorly defined. This review provides an account of the available data on ALI and ALF caused by bariatric surgery, with emphasis on potential injury mechanisms and the outcomes of liver transplantation for ALF after bariatric surgery.

Metabolomics in Bariatric Surgery: Towards Identification of Mechanisms and Biomarkers of Metabolic Outcomes

Bariatric surgery has been widely performed for the treatment of obesity and type 2 diabetes. Efforts have been made to investigate the mechanisms underlying the metabolic effects achieved by bariatric surgery and to identify candidates who will benefit from this surgery. Metabolomics, which includes comprehensive profiling of metabolites in biological samples, has been utilized for various disease entities to discover pathophysiological metabolic pathways and biomarkers predicting disease progression or prognosis. Over the last decade, metabolomic studies on patients undergoing bariatric surgery have identified significant biomarkers related to metabolic effects. This review describes the significance, progress, and challenges for the future of metabolomics in the area of bariatric surgery.

Long-Term Effects of Bariatric Surgery on Gut Microbiota Composition and Faecal Metabolome Related to Obesity Remission

Obesity is one of the main worldwide public health concerns whose clinical management demands new therapeutic approaches. Bariatric surgery is the most efficient treatment when other therapies have previously failed. Due to the role of gut microbiota in obesity development, the knowledge of the link between bariatric surgery and gut microbiota could elucidate new mechanistic approaches. This study aims to evaluate the long-term effects of bariatric surgery in the faecal metagenome and metabolome of patients with severe obesity. Faecal and blood samples were collected before and four years after the intervention from patients with severe obesity. Biochemical, metagenomic and metabolomic analyses were performed and faecal short-chain fatty acids were measured. Bariatric surgery improved the obesity-related status of patients and significantly reshaped gut microbiota composition. Moreover, this procedure was associated with a specific metabolome profile characterized by a reduction in energetic and amino acid metabolism. Acetate, butyrate and propionate showed a significant reduction with bariatric surgery. Finally, correlation analysis suggested the existence of a long-term compositional and functional gut microbiota profile associated with the intervention. In conclusion, bariatric surgery triggered long-lasting effects on gut microbiota composition and faecal metabolome that could be associated with the remission of obesity.