Major microbiota dysbiosis in severe obesity: fate after bariatric surgery

Gut Microbiota Disorders and Metabolic Syndrome: Tales of a Crosstalk Process

The microbiota in humans consists of trillions of microorganisms that are involved in the regulation of the gastrointestinal tract and immune and metabolic homeostasis. The gut microbiota (GM) has a prominent impact on the pathogenesis of metabolic syndrome (MetS). This process is reciprocal, constituting a crosstalk process between the GM and MetS. In this review, GM directly or indirectly inducing MetS via the host-microbial metabolic axis has been systematically reviewed. Additionally, the specifically altered GM in MetS are detailed in this review. Moreover, short-chain fatty acids (SCFAs), as unique gut microbial metabolites, have a remarkable effect on MetS, and the role of SCFAs in MetS-related diseases is highlighted to supplement the gaps in this area. Finally, the existing therapeutics are outlined, and the superiority and shortcomings of different therapeutic approaches are discussed, in hopes that this review can contribute to the development of potential treatment strategies.

Impact of bariatric surgery on gut microbiota in obese patients: A systematic review

BACKGROUND

Obesity is a multi-factorial disease linked to various metabolic disorders, including insulin resistance, type-2 diabetes (T2D) and cardiovascular diseases. Traditional treatments often show limited long-term success, while bariatric surgery has emerged as the most effective intervention for sustained weight loss and comorbidity improvement. Alterations in gut microbiota may significantly contribute to these metabolic improvements.

OBJECTIVE

This systematic review was aimed at evaluating changes in gut microbiota composition before and after bariatric surgery and their association with clinical outcomes, including weight loss, insulin sensitivity and lipid metabolism.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive search of PubMed, Scopus, Web of Science and clinicaltrials.gov databases was conducted for studies published between 2004 and 2024. Keywords included "bariatric surgery," "gut microbiota" and "obesity." Inclusion criteria focused on human studies with pre and post-surgical microbiota analysis. Non-human studies, pediatric populations and studies without microbiota assessment were excluded. Data extraction covered microbiota profiles, metabolic outcomes and clinical markers.

RESULTS

Total 27 articles and 28 clinical trials met the inclusion criteria. Pre-surgery, obese patients exhibited dysbiosis characterized by reduced microbial diversity and imbalances in key bacterial phyla. Post-surgery, especially after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), patients showed increased microbial diversity, reduced Firmicutes and elevated beneficial bacteria such as Akkermansia muciniphila and short-chain fatty acid (SCFA) producing bacteria. These microbiota changes were correlated with significant improvements in weight loss, insulin sensitivity and lipid profiles. However, some studies reported inconsistent or modest microbiota changes.

CONCLUSION

Bariatric surgery leads to significant gut microbiota alterations that are closely linked to metabolic improvements, including enhanced glucose control and lipid metabolism. However, the long-term sustainability of these microbial changes remains unclear. Longitudinal studies are essential to determine whether these alterations persist over time and how they continuously impact metabolic health. Further research should explore targeted microbiota interventions to maintain beneficial microbial profiles post-surgery.

A multi-omics microbiome signature is associated with the benefits of gastric bypass surgery and is differentiated from diet induced weight loss through 2 years of follow-up

Roux-en-Y gastric bypass (GBP) surgery is an effective treatment for reducing body weight and correcting metabolic dysfunction in individuals with severe obesity. Herein, we characterize the differences between very low energy diet (VLED) and GBP induced weight loss by multi-omic analyses of microbiome and host features in a non-randomized, controlled, single-center study. Eighty-eight participants with severe obesity were recruited into two arms - GBP versus VLED with matching weight loss for 6 weeks and 2-years of follow-up. A dramatic shift in the distribution of gut microbial taxa and their functional capacity was seen in the GBP group at Week 2 after surgery and was sustained through 2 years. Multi-omic analyses were performed after 6 weeks of matching weight loss between the GBP and VLED groups, which pointed to microbiome derived metabolites such as indoxyl sulphate as characterizing the GBP group. We also identified an inverse association between Streptococcus parasanguinis (an oral commensal) and plasma levels of tryptophan and tyrosine. These data have important implications, as they reveal a significant robust restructuring of the microbiome away from a baseline dysbiotic state in the GBP group. Furthermore, multi-omics modelling points to potentially novel mechanistic insights at the intersection of the microbiome and host.

A metabolomics and proteomics-based study on the metabolic effects of arecoline on the liver

Arecoline is one of the primary constituents of the areca nut. Its pharmacological effects include analgesia, anti-inflammation, and anti-allergy. Current researches on the toxicity of arecoline mainly focuse on oral carcinogenesis and immunotoxicity, so there are relatively little systematic study on its hepatotoxicity and underlying mechanisms. Therefore, this study aims to explore the mechanisms of hepatotoxicity induced by different doses of arecoline in mice by integrating metabolomics and proteomics. In our pathological results, we found that the medium and high dose groups of arecoline can cause fatty degeneration in the livers of mice. Additionally, the different doses of arecoline increased the levels of ALT and AST in the serum of mice. Proteomics research identified that exposure to different doses of arecoline primarily affected the PPARs signaling pathway, thereby influencing fatty acid metabolism, amino acid metabolism, and arachidonic acid metabolism pathways. Metabolomics research identified differential metabolites in each group after arecoline exposure. We observed that with increasing doses of arecoline, the metabolites of lipids and lipid-like molecules in mice gradually increased. The results suggested arecoline may induce fatty degeneration in the liver of mice through the PPARα/Acox-1 mediated pathways of oxidative stress, inflammatory response, energy, and lipid metabolism.

Obesity-associated Inflammation and Alloimmunity

Obesity is a worldwide health problem with a rapidly rising incidence. In organ transplantation, increasing numbers of patients with obesity accumulate on waiting lists and undergo surgery. Obesity is in general conceptualized as a chronic inflammatory disease, potentially impacting alloimmune response and graft function. Here, we summarize our current understanding of cellular and molecular mechanisms that control obesity-associated adipose tissue inflammation and provide insights into mechanisms affecting transplant outcomes, emphasizing on the beneficial effects of weight loss on alloimmune responses.

Obesity and its treatment: Toward new approaches

Obesity has until now been defined in terms of body mass index, a parameter which lacks sensitivity. The definition rather needs to take account of the pathophysiology and impact of the mechanical, metabolic and psychological complications associated with excess adiposity, as proposed by the French Health Authority in 2022. Initial phenotyping of pathophysiological determinants and complications make it possible to precisely define treatment objectives and the means used to achieve them. For example, excess adiposity is associated with hypervolemia, which increases the risk of heart failure independently of classic cardiovascular risk factors, due in particular to myocardial remodeling and diastolic dysfunction. In this indication, SGLT2 (sodium/glucose cotransporter 2) inhibitors may be relevant. A global approach, involving assessment of eating behavior and sensations, energy expenditure and emotional eating, enables us to identify drug treatments suited to each profile. Obesity is a recurrent pathology requiring the development of new combined or sequential drug treatments. Currently under development, inhibitors of the myostatin/activin A pathway conserve lean body mass during weight loss, a crucial factor in limiting weight regain and maintaining functional capacity. Beyond medical or surgical approaches to obesity, lifelong lifestyle interventions are central to improving quality of life and limiting the risks associated with excess adiposity.

MAGs-based genomic comparison of gut significantly enriched microbes in obese individuals pre- and post-bariatric surgery across diverse locations

Introduction

Obesity, a pressing global health issue, is intricately associated with distinct gut microbiota profiles. Bariatric surgeries, such as Laparoscopic Sleeve Gastrectomy (LSG), Sleeve Gastrectomy (SG), and Roux-en-Y Gastric Bypass (RYGB), induce substantial weight loss and reshape gut microbiota composition and functionality, yet their comparative impacts remain underexplored.

Methods

This study integrated four published metagenomic datasets, encompassing 500 samples, and employed a unified bioinformatics workflow for analysis. We assessed gut microbiota α-diversity, identified species biomarkers using three differential analysis approaches, and constructed high-quality Metagenome-Assembled Genomes (MAGs). Comparative genomic, functional profiling and KEGG pathway analyses were performed, alongside estimation of microbial growth rates via Peak-to-Trough Ratios (PTRs).

Results

RYGB exhibited the most pronounced enhancement of gut microbiota α-diversity compared to LSG and SG. Cross-cohort analysis identified 39 species biomarkers: 27 enriched in the non-obesity group (NonOB_Enrich) and 12 in the obesity group (OB_Enrich). Among the MAGs, 177 were NonOB_Enrich and 14 were OB_Enrich. NonOB_Enrich MAGs displayed enriched carbohydrate degradation profiles (e.g., GH105, GH2, GH23, GH43, and GT0 families) and higher gene diversity in fatty acid biosynthesis and secondary metabolite pathways, alongside significant enrichment in amino acid metabolism (KEGG analysis). Post-surgery, Akkermansia muciniphila and Bacteroides uniformis showed elevated growth rates based on PTRs.

Discussion

These findings underscore RYGB's superior impact on gut microbiota diversity and highlight distinct microbial functional adaptations linked to weight loss, offering insights for targeted therapeutic strategies.

Sleeve Gastrectomy and Gastric Bypass Impact in Patient's Metabolic, Gut Microbiome, and Immuno-inflammatory Profiles-A Comparative Study

BACKGROUND

Bariatric surgery is the most long-term effective treatment option for severe obesity. The role of gut microbiome (GM) in either the development of obesity or in response to obesity management strategies has been a matter of debate. This study aims to compare the impact of two of the most popular procedures, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (GB), on metabolic syndrome parameters and gut bacterial microbiome and in systemic immuno-inflammatory response.

METHODS

A prospective observational study enrolled 24 patients with severe obesity, 14 underwent SG and 10 GB. Evaluations before (0 M) and 6 months (6 M) after surgical procedures included clinical and biochemical parameters, expression of 17 immuno-inflammatory genes in peripheral blood leukocytes, and assessment of gut microbiome profile using 16 s rRNA next-generation sequencing approach. Statistical significance was set to a p value < 0.05 with an FDR < 0.1.

RESULTS

A significant and similar decrease in weight-associated parameters and for most metabolic markers was achieved with both surgeries. Considering the gut microbiome in the whole study population, there was an increase in alpha diversity at family-level taxa. Beta diversity between SG and GB at 6 M showed near significant differences (p = 0.042) at genus levels. Analysis of the relative abundance of individual taxonomic groups highlighted differences between pre- and post-surgical treatment and between both approaches, namely, a higher representation of family Enterobacteriaceae and genera Veillonella and Enterobacteriaceae_unclassified after GB. Increased expression of immune-inflammatory genes was observed mainly for SG patients.

CONCLUSIONS

We conclude that SG and GB have similar clinical and metabolic outcomes but different impacts in the gut bacterial microbiome. Results also suggest reactivation of immune response after bariatric surgery.

A menu for microbes: unraveling appetite regulation and weight dynamics through the microbiota-brain connection across the lifespan

Appetite, as the internal drive for food intake, is often dysregulated in a broad spectrum of conditions associated with over- and under-nutrition across the lifespan. Appetite regulation is a complex, integrative process comprising psychological and behavioral events, peripheral and metabolic inputs, and central neurotransmitter and metabolic interactions. The microbiota-gut-brain axis has emerged as a critical mediator of multiple physiological processes, including energy metabolism, brain function, and behavior. Therefore, the role of the microbiota-gut-brain axis in appetite and obesity is receiving increased attention. Omics approaches such as genomics, epigenomics, transcriptomics, proteomics, and metabolomics in appetite and weight regulation offer new opportunities for featuring obesity phenotypes. Furthermore, gut-microbiota-targeted approaches such as pre-, pro-, post-, and synbiotic, personalized nutrition, and fecal microbiota transplantation are novel avenues for precision treatments. The aim of this narrative review is 1) to provide an overview of the role of the microbiota-gut-brain axis in appetite regulation across the lifespan and 2) to discuss the potential of omics and gut microbiota-targeted approaches to deepen understanding of appetite regulation and obesity.

Rheumatic Diseases Following Metabolic and Bariatric Surgery: A Systematic Review and Meta-Analysis

Metabolic and bariatric surgery (MBS) has been associated with weight reduction and obesity complications improvement. However, there is no clear evidence of the extent and consistency of the effects of this procedure on rheumatic diseases. This study aims to conduct a meta-analysis to address the impact of MBS on rheumatic diseases. We searched PubMed, Cochrane, and Embase for studies reporting the prevalence of rheumatic diseases, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the medication use after MBS. We conducted a random-effects meta-analysis using odds ratios (OR) and mean differences (MD) with 95% confidence intervals (CI). P-values < 0.05 were considered statistically significant. We included 28 studies comprising 43,421 patients, with 13,347 patients with rheumatic diseases. The prevalence of osteoarthritis (OA), rheumatoid arthritis, and psoriatic arthritis was significantly reduced after MBS (OR 0.20; 95% CI 0.12 to 0.33; P = 0.01). The WOMAC index for patients with OA had a statistically significant overall reduction after MBS at 6 months (MD - 20.60 points; 95% CI - 28.73 to - 12.47; P < 0.01) and at 12 months (MD - 15.88 points; 95% CI - 19.09 to - 12.66; P < 0.01). Medication use significantly decreased after MBS, both at the follow-up beyond 2 years (OR 0.49; 95% CI 0.35 to 0.69; P < 0.01) and up to 2 years (OR 0.32; 95% CI 0.15 to 0.69; P < 0.01). In this meta-analysis, we found a significant decrease in the prevalence of rheumatic diseases, improvements in the WOMAC index, and reduced medication use among patients undergoing MBS.

A systematic review of the relationship between gut microbiota and prevalence of pancreatic diseases

Acute pancreatitis (AP) represents one of the most common gastrointestinal (GI) diseases; it can manifest in varying degrees of severity, sometimes leading to a life-threatening condition for the patient. Pancreatic ductal adenocarcinoma (PDAC), due to its high malignancy and uncertain prognosis, is widely regarded as one of the most fatal diseases. The increasing prevalence of AP and PDAC represents a major burden on public health and the healthcare system worldwide. The aim of this systematic review was to discuss the current state of knowledge regarding the relationship between the gut microbiota and the incidence, prognosis, diagnosis and treatment of AP and PDAC. To identify studies that analyzed the relationship between the gut microbiota and the occurrence/development of pancreatic diseases or PDAC, the online databases PubMed, Scopus and Google Scholar were searched between November 2023 and January 2024. Finally, 14 publications met the inclusion criteria (1. were conducted exclusively in humans and/or animals; 2. original, published in English in peer-reviewed journals after 2019; 3. described the relationship between gut microbiota and the occurrence of AP or PDAC). The collected studies indicated significant changes in the gut microbiota of patients with AP and PDAC. Moreover, they highlighted the presence of a relationship between the gut microbiota and the occurrence, course, treatment efficiency and prognosis of the disease in question. Further research is needed to understand precisely the relationship between the gut microbiota and the occurrence of pancreatic diseases and whether it may be a starting point for the development of modern forms of therapy based on the use of prebiotics and/or diet to restore the normal composition of the intestinal bacteria.

Roux-en-Y gastric bypass improves liver and glucose homeostasis in Zucker diabetic fatty rats by upregulating hepatic trefoil factor family 3 and activating the phosphatidylinositol 3-kinase/protein kinase B pathway

BACKGROUND

Roux-en-Y gastric bypass (RYGB) surgery is effective in ameliorating type 2 diabetes mellitus (T2DM); but its mechanism remains incompletely understood.

OBJECTIVES

This study aimed to investigate whether RYGB improves glucose metabolism by upregulating hepatic trefoil factor family 3 (TFF3) and thereby activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway.

SETTING

Affiliated Hospital of North Sichuan Medical college in Nanchong city, China.

METHODS

Zucker diabetic fatty (ZDF) rats underwent RYGB or sham surgery (SHAM), and Zucker lean (ZL) rats served as controls (CON). TFF3 expression and PI3K/Akt pathway activity were compared between groups using western blot, immunofluorescence, and RT-qPCR. Adeno-associated virus (AAV) was used to specifically overexpress and interfere with hepatic TFF3. Liver fibrosis and steatosis were assessed using Masson trichrome and Oil Red O staining. HepG2 cells overexpressing or knocking out TFF3 were constructed using lentiviral transfection and CRISPR/Cas9 technology. After verifying the activity of the PI3K/Akt pathway by western blot, rescue experiments were performed on HepG2 cell overexpressing and knocking out TFF3 using LY294002 and 740Y-P, respectively. The activities of gluconeogenic enzymes and glucose uptake capacity in different HepG2 cells were evaluated using qPCR and flow cytometry.

RESULTS

Compared with the SHAM group, the blood glucose, body weight, insulin resistance, and lipid metabolism of ZDF rats in the RYGB group were significantly improved. The expression of TFF3 and PI3K/Akt phosphorylation in the liver of the RYGB group were higher than those of the rats that had undergone SHAM. In addition, compared with the SHAM group, the liver fibrosis and fatty degeneration of RYGB rats were milder, and the activity of gluconeogenic enzymes was lower. After tail vein injection of AAV that specifically overexpresses liver TTF3 in rats in the SHAM group, rats' insulin resistance, glucose tolerance, gluconeogenic enzymes, and other glucose metabolism indicators improved. After tail vein injection of AAV that interferes with liver TFF3 in rats in the RYGB group, rats' glucose metabolism indicators deteriorated. In in vitro experiments, the PI3K/Akt activity of TFF3-knocked-out HepG2 cells was lower than that of other groups. Lower glucose concentration were observed in TFF3-overexpressing cell lines. After rescue experiments, differences were found. The glucose metabolism level of the TFF3-expressing HepG2 cell line was positively correlated with the activity of the PI3K/Akt pathway.

CONCLUSIONS

RYGB regulates the expression of TFF3 in the liver of ZDF rats, thereby activating the PI3K/Akt pathway and improving T2DM.

Integrated gut microbiome and UHPLC-MS metabolomics to reveal the prevention mechanism of pidanjiangtang granules on IGT Rats

INTRODUCTION

Pidanjiangtang (PDJT) is a traditional Chinese medicine formula empirically used to treat impaired glucose tolerance (IGT) based on the "Pidan" theory from the classic ancient book Nei Jing. However, the mechanism of PDJT intervention for IGT remains to be studied.

OBJECTIVE

This study aims to explore the mechanism of PDJT granules intervention in IGT by integrating gut microbiome and UHPLC-MS untargeted metabolomics.

MATERIALS AND METHODS

The IGT model was established in 6-week-old male Sprague-Dawley (SD) rats by feeding them a high-fat diet and using an STZ injection. The low, medium, and high doses of PDJT were used for six weeks. metformin (Glucophage) was used as the positive control drug. The efficacy of PDJT was evaluated using fasting blood glucose (FBG), blood glucose maximum (BGmax), blood lipid, and inflammatory factor levels. Finally, 16S rDNA gut microbiome sequencing with metabolomics analysis was used to explore the pharmacological mechanism of PDJT intervention in IGT.

RESULTS

PDJT could reverse the phenotype of IGT rats, reduce blood glucose levels, improve lipid metabolism disorder, and reduce inflammatory response. Gut microbiome analysis found that PDJT can improve gut microbiota composition and abundance of three phyla (Firmicutes, Bacteroidota, Desulfobacterota) and four genera (unclassified_f__Lachnospiraceae, Ruminococcus, Allobaculum, Desulfovibrio), which play an important role in the process of PDJT intervention on glucose metabolism and lipid metabolism in IGT rats. UHPLC-MS untargeted metabolomics showed that PDJT could regulate the levels of 258 metabolites in lipid metabolism pathways, inflammatory response pathways, fat and protein digestion, and absorption. The combined analysis of the two omics showed that improving the body's metabolism by gut microbes may be the possible mechanism of PDJT in treating IGT. Thus, this study provides a new method to integrate gut microbiome and UHPLC-MS untargeted metabolomics to evaluate the pharmacodynamics and mechanism of PDJT intervention in IGT, providing valuable ideas and insights for future research on the treatment of IGT with traditional Chinese medicine.

Interaction Between Early Meals (Big-Breakfast Diet), Clock Gene mRNA Expression, and Gut Microbiome to Regulate Weight Loss and Glucose Metabolism in Obesity and Type 2 Diabetes

The circadian clock gene system plays a pivotal role in coordinating the daily rhythms of most metabolic processes. It is synchronized with the light-dark cycle and the eating-fasting schedule. Notably, the interaction between meal timing and circadian clock genes (CGs) allows for optimizing metabolic processes at specific times of the day. Breakfast has a powerful resetting effect on the CG network. A misaligned meal pattern, such as skipping breakfast, can lead to a discordance between meal timing and the endogenous CGs, and is associated with obesity and T2D. Conversely, concentrating most calories and carbohydrates (CH) in the early hours of the day upregulates metabolic CG expression, thus promoting improved weight loss and glycemic control. Recently, it was revealed that microorganisms in the gastrointestinal tract, known as the gut microbiome (GM), and its derived metabolites display daily oscillation, and play a critical role in energy and glucose metabolism. The timing of meal intake coordinates the oscillation of GM and GM-derived metabolites, which in turn influences CG expression, playing a crucial role in the metabolic response to food intake. An imbalance in the gut microbiota (dysbiosis) can also reciprocally disrupt CG rhythms. Evidence suggests that misaligned meal timing may cause such disruptions and can lead to obesity and hyperglycemia. This manuscript focuses on the reciprocal interaction between meal timing, GM oscillation, and circadian CG rhythms. It will also review studies demonstrating how aligning meal timing with the circadian clock can reset and synchronize CG rhythms and GM oscillations. This synchronization can facilitate weight loss and improve glycemic control in obesity and those with T2D.

Gastrointestinal complaints after Roux-en-Y gastric bypass surgery. Impact of microbiota and its metabolites

Unexplainable gastrointestinal complaints occasionally occur after Roux-en-Y Gastric Bypass (RYGB) surgery. We therefor investigated the impact of microbiota composition and metabolites on gastrointestinal complaints after RYGB. In the BARICO study (Bariatric surgery Rijnstate and Radboudumc neuroimaging and Cognition in Obesity), microbiota and metabolites were measured before surgery, and 6, and 24 months after surgery. Gastrointestinal complaints were assessed with the Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) questionnaire 24 months after surgery. 65 participants (86.2 % female) with a mean age of 46.2 ± 6.0 years, and mean BMI of 41.2 ± 3.6 kg/m2 were included. According to the IBS-SSS questionnaire, 32.3 % had moderate/severe gastrointestinal complaints 24 months after surgery. Microbiota alpha diversity remained stable, while beta diversity significantly changed over time. Bile acids and short-chain fatty acids were significantly higher, and inflammatory markers significantly lower after surgery. Barnesiella sp., Escherichia/Shigella sp., and Faecalibacterium prausnitzii correlated positively, while Akkermansia sp correlated inversely with gastrointestinal complaints. Patients with mild and moderate/severe gastrointestinal complaints showed higher levels of GLC-3S. These findings suggest involvement of microbiota and metabolite changes in gastrointestinal complaints after surgery. However, it remains unclear whether bacteria influence gastrointestinal complaints directly or indirectly. Further exploration is required for development of interventions against gastrointestinal symptoms after surgery.

Current challenges and future perspectives in treating patients with NAFLD-related cirrhosis

Despite the slow, progressive nature of NAFLD, the number of patients with NAFLD-related cirrhosis has significantly increased. Although the management of patients with cirrhosis is constantly evolving, improving the prognosis of patients with NAFLD-related cirrhosis is a challenge because it is situated at the crossroads between the liver, the metabolic, and the cardiovascular diseases. Therefore, the therapeutic interventions should not only target the liver but also the associated cardiometabolic conditions and should be adapted accordingly. The objective of the current review is to critically discuss the particularities in the management of patients with NAFLD-related cirrhosis. We relied on the recommendations of scientific societies and discussed them in the specific context of NAFLD cirrhosis and the surrounding cardiometabolic milieu. Herein, we covered the following aspects: (1) the weight loss strategies through lifestyle interventions to avoid sarcopenia and improve portal hypertension; (2) the optimal control of metabolic comorbidities in particular type 2 diabetes aimed not only to improve cardiovascular morbidity/mortality but also to lower the incidence of cirrhosis-related complications (we discussed various aspects related to the safety of oral antidiabetic drugs in cirrhosis); (3) the challenges in performing bariatric surgery in patients with cirrhosis related to the portal hypertension and the risk of cirrhosis decompensation; (4) the particularities in the diagnosis and management of the portal hypertension and the difficulties in managing patients awaiting for liver transplantation; and (5) the difficulties in developing drugs and conducting clinical trials in patients with NAFLD-related cirrhosis. Moreover, we discussed the emerging options to overcome these obstacles.

Potential Anti-Obesity Effect of Hazel Leaf Extract in Mice and Network Pharmacology of Selected Polyphenols

Background: Obesity is gradually becoming a widespread health problem, and treatment using natural compounds has seen an increasing trend. As a by-product of hazelnut, hazel leaf is usually disposed of as waste, but it is widely used in traditional and folk medicines around the world. Aim of this study: Based on previous studies, the effects of the regulation of lipid metabolism and the mechanism of hazel leaf polyphenol extraction obesity were investigated. Methods: In this study, a high-fat diet-fed mouse model of obesity and 3T3-L1 preadipocytes were established. The ameliorative effects of the hazel leaf polyphenol extract on obesity and the regulating lipid metabolisms were explored based on network pharmacology, gut microbiota, and molecular docking. Results: Network pharmacology showed that hazel leaf polyphenols may play a role by targeting key targets, including PPARγ, and regulating the PPAR signaling pathway. They significantly improved body weight gain, the liver index, and adiposity and lipid levels; regulated the gut microbiota and short-chain fatty acid contents; down-regulated the expression of lipid synthesis proteins SREBP1c, PPARγ, and C/EBP-α; and up-regulated the expression of p-AMPK in obese mice. They inhibited the differentiation of 3T3-L1 cells, and the expression of related proteins is consistent with the results in vivo. The molecular docking results indicated that gallic acid, quercetin-3-O-beta-D-glucopyranoside, quercetin, myricetin, and luteolin-7-O-glucoside in the hazel leaf polyphenol extract had strong binding activities with PPARγ, C/EBP-α, and AMPK. Conclusions: The results demonstrate that the hazel leaf polyphenol extract can improve obesity by regulating lipid metabolism, which provides a valuable basis for developing health products made from hazel leaf polyphenols in the future.

Intestinal Energy Harvest Mediates Gut Microbiota-Associated Weight Loss Following Bariatric Surgery

PURPOSE

Metabolic and bariatric surgery (MBS) is the most effective treatment for class III obesity. The capacity to efficiently extract intestinal energy is potentially a determinant of varying weight loss outcomes post-MBS. Prior research indicated that intestinal energy harvest is correlated with post-MBS weight loss. Studies have also demonstrated that the gut microbiota is associated with weight loss post-MBS. We aim to investigate whether gut microbiota-associated weight loss is mediated by intestinal energy harvest in patients post-MBS.

MATERIALS AND METHODS

We examined the relationship between specific gut microbiota, intestinal energy harvest, diet, and weight loss using fecal metagenomic sequence data, bomb calorimetry (fecal energy content as a proxy for calorie absorption), and a validated dietary questionnaire on 67 individuals before and after MBS. Mediation analysis and a machine learning algorithm were conducted.

RESULTS

Intestinal energy harvest was a mediator in the relationship between the intestinal microbiota (Bacteroides caccae) and weight loss outcomes in patients post-MBS at 18 months (M). The association between the abundance of B. caccae and post-MBS weight loss rate at 18 M was partly mediated by 1 M intestinal energy harvest (β = 0.001 ± 0.001, P = 0.020). This mediation represents 2.83% of the total effect (β = 0.050 ± 0.047; P = 0.028). Intestinal microbiota and energy harvest improved random forest model's accuracy in predicting weight loss results.

CONCLUSION

Energy harvest partly mediates the relationship between the intestinal microbiota and weight loss outcomes among patients post-MBS. This study elucidates a potential mechanism regarding how intestinal energy absorption facilitates the effect of intestinal microbiota on energy metabolism and weight loss outcomes.

Causal relationship between gut microbiota and childhood obesity: A Mendelian randomization study and case-control study

BACKGROUND

Gut microbiota and obesity are deeply interconnected. However, the causality in the relationship between these factors remains unclear. Therefore, this study aimed to elucidate the genetic relationship between gut microbiota and childhood obesity.

METHODS

Genetic summary statistics for the gut microbiota were obtained from the MiBioGen consortium. Genome-wide association studies (GWAS) summary data for childhood obesity were obtained from North American, Australian, and European collaborative genome-wide meta-analyses. Mendelian randomization (MR) analyses were performed using the inverse variance weighting method. 16 children with obesity and 16 without obesity were included for clinical observation, and their weight, body mass index, blood lipid levels, and gut microbiology were assessed. Paired t-test was the primary method of data analysis, and statistical significance was set at P < 0.05.

RESULTS

MR identified 16 causal relationships between the gut microbiome and childhood obesity. In the case-control study, we found that five gut microorganisms differed between children with and without obesity, whereas three gut microorganisms changed after weight loss in children with obesity.

CONCLUSION

Our study provides new insights into the genetic mechanisms underlying gut microbiota and childhood obesity.

TRIAL REGISTRATION NUMBER

ChiCTR2300072179.

NAME OF REGISTRY

Change of intestinal flora and plasma metabolome in obese children and their weight loss intervention: a randomized controlled tria URL OF REGISTRY: https://www.chictr.org.cn/showproj.html.

DATE OF REGISTRATION

2023-06-06.

DATE OF ENROLMENT OF THE FIRST PARTICIPANT TO THE TRIAL

2023-06-07.

Weight change and lifestyle modifications implemented during the COVID-19 pandemic lockdown are associated with the development of gastrointestinal symptoms

INTRODUCTION AND AIMS

Pandemic lockdown measures are a cause of concern, regarding their negative impact on the mental health of individuals. The results of numerous studies have associated the appearance of gastrointestinal symptoms with different psychologic disorders, such as stress, depression, and anxiety, due to gut-brain axis interaction. The aim of the present study was to determine the prevalence of, and factors associated with, gastrointestinal symptom onset related to the COVID-19 pandemic lockdown and various lifestyle modifications.

METHODS

An analytic, observational, and cross-sectional study was conducted on an open population that agreed to participate within the time frame of January to May 2021.

RESULTS

A total of 298 subjects, 165 of whom were women (55.4%), agreed to participate and the mean patient age was 36.1 ± 12.6 years. There was a significant increase in the frequency of several gastrointestinal symptoms: epigastric burning, early satiety, heartburn, regurgitation, constipation, and diarrhea. Changes in weight and modifications in lifestyle were found to be associated variables.

CONCLUSIONS

The results of this study showed a significant increase in a wide variety of gastrointestinal symptoms related to lifestyle changes due to the pandemic lockdown. Weight change, supplement and multivitamin intake, and reduced physical activity were the main associated risk factors. Public healthcare systems should take a multidisciplinary approach into consideration for the care of affected individuals.

Molecular Mechanisms Affecting Statin Pharmacokinetics after Bariatric Surgery

According to recent data, one in eight people in the world struggle with obesity. Obesity management is increasingly dependent on bariatric surgical interventions, as the combination of lifestyle modifications and pharmacotherapy could have a modest long-term effect. Surgery is recommended only for individuals whose body mass index (BMI) ≥ 40 kg/m2 and ≥ 35 kg/m2 in the presence of weight-related comorbidities. The most commonly performed procedures are sleeve gastrectomy and roux-en-Y gastric bypass. Pharmacokinetic and pharmacodynamic alterations occur as a result of the anatomical and physiological changes caused by surgery, which further differ depending on physicochemical drug factors and factors related to the dosage form. The following modifications are distinguished based on the type of bariatric surgery performed. Most bariatric patients have accompanying comorbidities, including dyslipidemia treated with hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins. Significant improvements in the lipid profile are observed early in the postoperative period. The data reported in this review on statin pharmacokinetic alterations have demonstrated substantial inter- and intravariability, making it difficult to adopt clear guidelines. Based on the current literature review, reducing the statin dose to the lowest effective with continuous monitoring is considered an optimal approach in clinical practice.

Integrative microbiome and metabolome profiles reveal the impacts of periodontitis via oral-gut axis in first-trimester pregnant women

BACKGROUND

Periodontitis results from host-microbe dysbiosis and the resultant dysregulated immunoinflammatory response. Importantly, it closely links to numerous systemic comorbidities, and perplexingly contributes to adverse pregnancy outcomes (APOs). Currently, there are limited studies on the distal consequences of periodontitis via oral-gut axis in pregnant women. This study investigated the integrative microbiome-metabolome profiles through multi-omics approaches in first-trimester pregnant women and explored the translational potentials.

METHODS

We collected samples of subgingival plaques, saliva, sera and stool from 54 Chinese pregnant women at the first trimester, including 31 maternal periodontitis (Perio) subjects and 23 Non-Perio controls. By integrating 16S rRNA sequencing, untargeted metabolomics and clinical traits, we explored the oral-gut microbial and metabolic connection resulting from periodontitis among early pregnant women.

RESULTS

We demonstrated a novel bacterial distinguisher Coprococcus from feces of periodontitis subjects in association with subgingival periodontopathogens, being different from other fecal genera in Lachnospiraceae family. The ratio of fecal Coprococcus to Lachnoclostridium could discriminate between Perio and Non-Perio groups as the ratio of subgingival Porphyromonas to Rothia did. Furthermore, there were differentially abundant fecal metabolic features pivotally enriched in periodontitis subjects like L-urobilin and kynurenic acid. We revealed a periodontitis-oriented integrative network cluster, which was centered with fecal Coprococcus and L-urobilin as well as serum triglyceride.

CONCLUSIONS

The current findings about the notable influence of periodontitis on fecal microbiota and metabolites in first-trimester pregnant women via oral-gut axis signify the importance and translational implications of preconceptional oral/periodontal healthcare for enhancing maternal wellbeing.

Advancements in Understanding and Preventing Obesity-Related Colon Cancer

ABSTRACT

Obesity and colorectal cancer are global public health issues, with the prevalence of both conditions increasing over the last 4 decades. In the United States alone, the prevalence of obesity is greater than 40%, and this percentage is projected to increase past 50% by 2030. This review focuses on understanding the association between obesity and the risk of colorectal cancer while also highlighting hypotheses about molecular mechanisms underlying the link between these disease processes. We also consider whether those linkages can be disrupted via weight loss therapies, including lifestyle modifications, pharmacotherapy, bariatric surgery, and endobariatrics.

Faecal microbiota transplantation in children: A systematic review

AIM

Novel technologies offer insights into the potential role of the intestinal microbiota in human health and disease. Dysbiosis has been associated with several diseases, and it is thought to play a role in the pathogenesis of different gastrointestinal diseases. Faecal microbiota transplantation (FMT) is emerging as a method to modulate the gastrointestinal microbial ecosystem. While recurrent Clostridioides difficile infection is the recognised FMT indication, exploration of other therapeutic uses is ongoing.

METHODS

Following PRISMA guidelines, we conducted a systematic review, extracting 583 articles from Embase and PubMed (index date to October 2022).

RESULTS

The search yielded 58 studies for full review, with 50 included in the systematic review. Articles were categorised by FMT indication, study design, efficacy, adverse events, donor selection and administration route. FMT appears safe and effective for recurrent Clostridioides difficile infection, although severe adverse events are reported in children. However, there are currently insufficient data to support the use of FMT for other potential therapeutic indications (such as irritable or inflammatory bowel disease or obesity), beside the potential to decolonise multi-drug resistant organisms.

CONCLUSION

This underscores the need for randomised, controlled, prospective cohort studies in children to assess FMT effectiveness in diverse conditions and counteract publication bias.

Incretin hormones, obesity and gut microbiota

Over the past 40 years, the prevalence of obesity has risen dramatically, reaching epidemic proportions. By 2030 the number of people affected by obesity will reach 1.12 billion worldwide. Gastrointestinal hormones, namely incretins, play a vital role in the pathogenesis of obesity and its comorbidities. GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1), which are secreted from the intestine after nutrient intake and stimulate insulin secretion from pancreatic β cells, influence lipid metabolism, gastric empting, appetite and body weight. The gut microbiota plays an important role in various metabolic conditions, including obesity and type 2 diabetes and influences host metabolism through the interaction with enteroendocrine cells that modulate incretins secretion. Gut microbiota metabolites, such as short-chain fatty acids (SCFAs) and indole, directly stimulate the release of incretins from colonic enteroendocrine cells influencing host satiety and food intake. Moreover, bariatric surgery and incretin-based therapies are associated with increase gut bacterial richness and diversity. Understanding the role of incretins, gut microbiota, and their metabolites in regulating metabolic processes is crucial to develop effective strategies for the management of obesity and its associated comorbidities.

The Potential Mechanism of Remission in Type 2 Diabetes Mellitus After Vertical Sleeve Gastrectomy

In recent years, there has been a gradual increase in the prevalence of obesity and type 2 diabetes mellitus (T2DM), with bariatric surgery remaining the most effective treatment strategy for these conditions. Vertical sleeve gastrectomy (VSG) has emerged as the most popular surgical procedure for bariatric/metabolic surgeries, effectively promoting weight loss and improving or curing T2DM. The alterations in the gastrointestinal tract following VSG may improve insulin secretion and resistance by increasing incretin secretion (especially GLP-1), modifying the gut microbiota composition, and through mechanisms dependent on weight loss. This review focuses on the potential mechanisms through which the enhanced action of incretin and metabolic changes in the digestive system after VSG may contribute to the remission of T2DM.

Changes in the Human Gut Microbiome Caused by the Short-Term Impact of Lactic Acid Bacteria Consumption in Healthy People

The gut microbiome is one of the main factors affecting human health. It has been proven that probiotics can regulate the metabolism in the host body. A large number of people use probiotics not as medicines, but as a prophylactic supplement. The aim of our study was to evaluate the effect of lactic acid bacteria on the gut microbiome of healthy people using the V3 region of the 16S rRNA gene. Our study showed changes in the generic composition in the gut of healthy people when taking the supplement. There was an increase in the members responsible for the production of short-chain fatty acids in the gut of the host (Blautia, Fusicatenibacter, Eubacterium hallii group, Ruminococcus), as well as bacteria that improve intestinal homeostasis (Dorea and Barnesiella). There was also a decrease in the abundance of bacteria in the genera Catenibacterium, Hungatella, Escherichia-Shigella, and Pseudomonas, associated with an unhealthy profile of the human gut microbiome. An increase in members of the phylum Actinobacteriota was also observed, which has a positive effect on the host organism. Our results indicate that short-term prophylactic use of lactic acid bacteria-based supplements can be effective, as it contributes to a beneficial effect on the gut microbiome of healthy people.

Gut resistome linked to sexual preference and HIV infection

BACKGROUND

People living with HIV (PLWH) are at increased risk of acquisition of multidrug resistant organisms due to higher rates of predisposing factors. The gut microbiome is the main reservoir of the collection of antimicrobial resistance determinants known as the gut resistome. In PLWH, changes in gut microbiome have been linked to immune activation and HIV-1 associated complications. Specifically, gut dysbiosis defined by low microbial gene richness has been linked to low Nadir CD4 + T-cell counts. Additionally, sexual preference has been shown to strongly influence gut microbiome composition in PLWH resulting in different Prevotella or Bacteroides enriched enterotypes, in MSM (men-who-have-sex-with-men) or no-MSM, respectively. To date, little is known about gut resistome composition in PLWH due to the scarcity of studies using shotgun metagenomics. The present study aimed to detect associations between different microbiome features linked to HIV-1 infection and gut resistome composition.

RESULTS

Using shotgun metagenomics we characterized the gut resistome composition of 129 HIV-1 infected subjects showing different HIV clinical profiles and 27 HIV-1 negative controls from a cross-sectional observational study conducted in Barcelona, Spain. Most no-MSM showed a Bacteroides-enriched enterotype and low microbial gene richness microbiomes. We did not identify differences in resistome diversity and composition according to HIV-1 infection or immune status. However, gut resistome was more diverse in MSM group, Prevotella-enriched enterotype and gut micorbiomes with high microbial gene richness compared to no-MSM group, Bacteroides-enriched enterotype and gut microbiomes with low microbial gene richness. Additionally, gut resistome beta-diversity was different according to the defined groups and we identified a set of differentially abundant antimicrobial resistance determinants based on the established categories.

CONCLUSIONS

Our findings reveal a significant correlation between gut resistome composition and various host variables commonly associated with gut microbiome, including microbiome enterotype, microbial gene richness, and sexual preference. These host variables have been previously linked to immune activation and lower Nadir CD4 + T-Cell counts, which are prognostic factors of HIV-related comorbidities. This study provides new insights into the relationship between antibiotic resistance and clinical characteristics of PLWH.

IMPROVE 2022 International Meeting on Pathway-Related Obesity: Vision of Excellence

Nearly 90 clinicians and researchers from around the world attended the first IMPROVE 2022 International Meeting on Pathway-Related Obesity. Delegates attended in person or online from across Europe, Argentina and Israel to hear the latest scientific and clinical developments in hyperphagia and severe, early-onset obesity, and set out a vision of excellence for the future for improving the diagnosis, treatment, and care of patients with melanocortin-4 receptor (MC4R) pathway-related obesity. The meeting co-chair Peter Kühnen, Charité Universitätsmedizin Berlin, Germany, indicated that change was needed with the rapidly increasing prevalence of obesity and the associated complications to improve the understanding of the underlying mechanisms and acknowledge that monogenic forms of obesity can play an important role, providing insights that can be applied to a wider group of patients with obesity. World-leading experts presented the latest research and led discussions on the underlying science of obesity, diagnosis (including clinical and genetic approaches such as the role of defective MC4R signalling), and emerging clinical data and research with targeted pharmacological approaches. The aim of the meeting was to agree on the questions that needed to be addressed in future research and to ensure that optimised diagnostic work-up was used with new genetic testing tools becoming available. This should aid the planning of new evidence-based treatment strategies for the future, as explained by co-chair Martin Wabitsch, Ulm University Medical Center, Germany.

Effects of dietary fibre on metabolic health and obesity

Obesity and metabolic syndrome represent a growing epidemic worldwide. Body weight is regulated through complex interactions between hormonal, neural and metabolic pathways and is influenced by numerous environmental factors. Imbalances between energy intake and expenditure can occur due to several factors, including alterations in eating behaviours, abnormal satiation and satiety, and low energy expenditure. The gut microbiota profoundly affects all aspects of energy homeostasis through diverse mechanisms involving effects on mucosal and systemic immune, hormonal and neural systems. The benefits of dietary fibre on metabolism and obesity have been demonstrated through mechanistic studies and clinical trials, but many questions remain as to how different fibres are best utilized in managing obesity. In this Review, we discuss the physiochemical properties of different fibres, current findings on how fibre and the gut microbiota interact to regulate body weight homeostasis, and knowledge gaps related to using dietary fibres as a complementary strategy. Precision medicine approaches that utilize baseline microbiota and clinical characteristics to predict individual responses to fibre supplementation represent a new paradigm with great potential to enhance weight management efficacy, but many challenges remain before these approaches can be fully implemented.

In Vivo Tissue Distribution of Polystyrene or Mixed Polymer Microspheres and Metabolomic Analysis after Oral Exposure in Mice

BACKGROUND

Global plastic use has consistently increased over the past century with several different types of plastics now being produced. Much of these plastics end up in oceans or landfills leading to a substantial accumulation of plastics in the environment. Plastic debris slowly degrades into microplastics (MPs) that can ultimately be inhaled or ingested by both animals and humans. A growing body of evidence indicates that MPs can cross the gut barrier and enter into the lymphatic and systemic circulation leading to accumulation in tissues such as the lungs, liver, kidney, and brain. The impacts of mixed MPs exposure on tissue function through metabolism remains largely unexplored.

OBJECTIVES

This study aims to investigate the impacts of polymer microspheres on tissue metabolism in mice by assessing the microspheres ability to translocate across the gut barrier and enter into systemic circulation. Specifically, we wanted to examine microsphere accumulation in different organ systems, identify concentration-dependent metabolic changes, and evaluate the effects of mixed microsphere exposures on health outcomes.

METHODS

To investigate the impact of ingested microspheres on target metabolic pathways, mice were exposed to either polystyrene (5 μ m ) microspheres or a mixture of polymer microspheres consisting of polystyrene (5 μ m ), polyethylene (1 - 4 μ m ), and the biodegradability and biocompatible plastic, poly-(lactic-co-glycolic acid) (5 μ m ). Exposures were performed twice a week for 4 weeks at a concentration of either 0, 2, or 4 mg / week via oral gastric gavage. Tissues were collected to examine microsphere ingress and changes in metabolites.

RESULTS

In mice that ingested microspheres, we detected polystyrene microspheres in distant tissues including the brain, liver, and kidney. Additionally, we report on the metabolic differences that occurred in the colon, liver, and brain, which showed differential responses that were dependent on concentration and type of microsphere exposure.

DISCUSSION

This study uses a mouse model to provide critical insight into the potential health implications of the pervasive issue of plastic pollution. These findings demonstrate that orally consumed polystyrene or mixed polymer microspheres can accumulate in tissues such as the brain, liver, and kidney. Furthermore, this study highlights concentration-dependent and polymer type-specific metabolic changes in the colon, liver, and brain after plastic microsphere exposure. These results underline the mobility within and between biological tissues of MPs after exposure and emphasize the importance of understanding their metabolic impact. https://doi.org/10.1289/EHP13435.

Molecular mechanism and therapeutic significance of essential amino acids in metabolically associated fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), also known as metabolically associated fatty liver disease (MAFLD), is a systemic metabolic disease characterized by lipid accumulation in the liver, lipid toxicity, insulin resistance, intestinal dysbiosis, and inflammation that can progress from simple steatosis to nonalcoholic steatohepatitis (NASH) and even cirrhosis or cancer. It is the most prevalent illness threatening world health. Currently, there are almost no approved drug interventions for MAFLD, mainly dietary changes and exercise to control weight and regulate metabolic disorders. Meanwhile, the metabolic pathway involved in amino acid metabolism also influences the onset and development of MAFLD in the body, and most amino acid metabolism takes place in the liver. Essential amino acids are those amino acids that must be supplemented from outside the diet and that cannot be synthesized in the body or cannot be synthesized at a rate sufficient to meet the body's needs, including leucine, isoleucine, valine (collectively known as branched-chain amino acids), tryptophan, phenylalanine (which are aromatic amino acids), histidine, methionine, threonine and lysine. The metabolic balance of the body is closely linked to these essential amino acids, and essential amino acids are closely linked to the pathophysiological process of MAFLD. In this paper, we will focus on the metabolism of essential amino acids in the body and further explore the therapeutic strategies for MAFLD based on the studies conducted in recent years.

Deep learning methods in metagenomics: a review

The ever-decreasing cost of sequencing and the growing potential applications of metagenomics have led to an unprecedented surge in data generation. One of the most prevalent applications of metagenomics is the study of microbial environments, such as the human gut. The gut microbiome plays a crucial role in human health, providing vital information for patient diagnosis and prognosis. However, analysing metagenomic data remains challenging due to several factors, including reference catalogues, sparsity and compositionality. Deep learning (DL) enables novel and promising approaches that complement state-of-the-art microbiome pipelines. DL-based methods can address almost all aspects of microbiome analysis, including novel pathogen detection, sequence classification, patient stratification and disease prediction. Beyond generating predictive models, a key aspect of these methods is also their interpretability. This article reviews DL approaches in metagenomics, including convolutional networks, autoencoders and attention-based models. These methods aggregate contextualized data and pave the way for improved patient care and a better understanding of the microbiome's key role in our health.

Gut microbiota and therapy for obesity and type 2 diabetes

There has been a major increase in Type 2 diabetes and obesity in many countries, and this will lead to a global public health crisis, which not only impacts on the quality of life of individuals well but also places a substantial burden on healthcare systems and economies. Obesity is linked to not only to type 2 diabetes but also cardiovascular diseases, musculoskeletal disorders, and certain cancers, also resulting in increased medical costs and diminished quality of life. A number of studies have linked changes in gut in obesity development. Dysbiosis, a deleterious change in gut microbiota composition, leads to altered intestinal permeability, associated with obesity and Type 2 diabetes. Many factors affect the homeostasis of gut microbiota, including diet, genetics, circadian rhythms, medication, probiotics, and antibiotics. In addition, bariatric surgery induces changes in gut microbiota that contributes to the metabolic benefits observed post-surgery. Current obesity management strategies encompass dietary interventions, exercise, pharmacotherapy, and bariatric surgery, with emerging treatments including microbiota-altering approaches showing promising efficacy. While pharmacotherapy has demonstrated significant advancements in recent years, bariatric surgery remains one of the most effective treatments for sustainable weight loss. However, access to this is generally limited to those living with severe obesity. This underscores the need for non-surgical interventions, particularly for adolescents and mildly obese patients. In this comprehensive review, we assess longitudinal alterations in gut microbiota composition and functionality resulting from the two currently most effective anti-obesity treatments: pharmacotherapy and bariatric surgery. Additionally, we highlight the functions of gut microbiota, focusing on specific bacteria, their metabolites, and strategies for modulating gut microbiota to prevent and treat obesity. This review aims to provide insights into the evolving landscape of obesity management and the potential of microbiota-based approaches in addressing this pressing global health challenge.

Perturbation and resilience of the gut microbiome up to 3 months after β-lactams exposure in healthy volunteers suggest an important role of microbial β-lactamases

BACKGROUND

Antibiotics notoriously perturb the gut microbiota. We treated healthy volunteers either with cefotaxime or ceftriaxone for 3 days, and collected in each subject 12 faecal samples up to day 90. Using untargeted and targeted phenotypic and genotypic approaches, we studied the changes in the bacterial, phage and fungal components of the microbiota as well as the metabolome and the β-lactamase activity of the stools. This allowed assessing their degrees of perturbation and resilience.

RESULTS

While only two subjects had detectable concentrations of antibiotics in their faeces, suggesting important antibiotic degradation in the gut, the intravenous treatment perturbed very significantly the bacterial and phage microbiota, as well as the composition of the metabolome. In contrast, treatment impact was relatively low on the fungal microbiota. At the end of the surveillance period, we found evidence of resilience across the gut system since most components returned to a state like the initial one, even if the structure of the bacterial microbiota changed and the dynamics of the different components over time were rarely correlated. The observed richness of the antibiotic resistance genes repertoire was significantly reduced up to day 30, while a significant increase in the relative abundance of β-lactamase encoding genes was observed up to day 10, consistent with a concomitant increase in the β-lactamase activity of the microbiota. The level of β-lactamase activity at baseline was positively associated with the resilience of the metabolome content of the stools.

CONCLUSIONS

In healthy adults, antibiotics perturb many components of the microbiota, which return close to the baseline state within 30 days. These data suggest an important role of endogenous β-lactamase-producing anaerobes in protecting the functions of the microbiota by de-activating the antibiotics reaching the colon. Video Abstract.

Gut microbiome signature of metabolically healthy obese individuals according to anthropometric, metabolic and inflammatory parameters

In this study, we investigated the characteristics of gut microbiome in the metabolically healthy obese (MHO) patients, and how they correlate with metabolic and inflammatory profiles. A total of 120 obese people without metabolic comorbidities were recruited, and their clinical phenotypes, metabolic and inflammatory parameters were analysed. The faecal microbial markers originating from bacterial cell and extracellular vesicle (EV) were profiled using 16S rDNA sequencing. The total study population could be classified into two distinct enterotypes (enterotype I: Prevotellaceae-predominant, enterotype II: Akkermansia/Bacteroides-predominant), based on their stool EV-derived microbiome profile. When comparing the metabolic and inflammatory profiles, subjects in enterotype I had higher levels of serum IL-1β [false discovery rate (FDR) q = 0.050] and had a lower level of microbial diversity than enterotype II (Wilcoxon rank-sum test p < 0.01). Subjects in enterotype I had relatively higher abundance of Bacteroidetes, Prevotellaceae and Prevotella-derived EVs, and lower abundance of Actinobacteria, Firmicutes, Proteobacteria, Akkermansia and Bacteroides-derived EVs (FDR q < 0.05). In conclusion, HMO patients can be categorised into two distinct enterotypes by the faecal EV-derived microbiome profile. The enterotyping may be associated with different metabolic and inflammatory profiles. Further studies are warranted to elucidate the long-term prognostic impact of EV-derived microbiome in the obese population.

New mechanistic insights of anti-obesity by sleeve gastrectomy-altered gut microbiota and lipid metabolism

Background

The obesity epidemic has been on the rise due to changes in living standards and lifestyles. To combat this issue, sleeve gastrectomy (SG) has emerged as a prominent bariatric surgery technique, offering substantial weight reduction. Nevertheless, the mechanisms that underlie SG-related bodyweight loss are not fully understood.

Methods

In this study, we conducted a collection of preoperative and 3-month postoperative serum and fecal samples from patients who underwent laparoscopic SG at the First Affiliated Hospital of Shandong First Medical University (Jinan, China). Here, we took an unbiased approach of multi-omics to investigate the role of SG-altered gut microbiota in anti-obesity of these patients. Non-target metabolome sequencing was performed using the fecal and serum samples.

Results

Our data show that SG markedly increased microbiota diversity and Rikenellaceae, Alistipes, Parabacteroides, Bactreoidales, and Enterobacteraies robustly increased. These compositional changes were positively correlated with lipid metabolites, including sphingolipids, glycerophospholipids, and unsaturated fatty acids. Increases of Rikenellaceae, Alistipes, and Parabacteroide were reversely correlated with body mass index (BMI).

Conclusion

In conclusion, our findings provide evidence that SG induces significant alterations in the abundances of Rikenellaceae, Alistipes, Parabacteroides, and Bacteroidales, as well as changes in lipid metabolism-related metabolites. Importantly, these changes were found to be closely linked to the alleviation of obesity. On the basis of these findings, we have identified a number of microbiotas that could be potential targets for treatment of obesity.

Probiotic-Induced Modulation of Microbiota Composition and Antibiotic Resistance Genes Load, an In Vitro Assessment

The imbalance of the gut microbiota (GM) is known as dysbiosis and is associated with disorders such as obesity. The increasing prevalence of microorganisms harboring antibiotic resistance genes (ARG) in the GM has been reported as a potential risk for spreading multi-drug-resistant pathogens. The objective of this work was the evaluation, in a fecal culture model, of different probiotics for their ability to modulate GM composition and ARG levels on two population groups, extremely obese (OB) and normal-weight (NW) subjects. Clear differences in the basal microbiota composition were observed between NW and OB donors. The microbial profile assessed by metataxonomics revealed the broader impact of probiotics on the OB microbiota composition. Also, supplementation with probiotics promoted significant reductions in the absolute levels of tetM and tetO genes. Regarding the blaTEM gene, a minor but significant decrease in both donor groups was detected after probiotic addition. A negative association between the abundance of Bifidobacteriaceae and the tetM gene was observed. Our results show the ability of some of the tested strains to modulate GM. Moreover, the results suggest the potential application of probiotics for reducing the levels of ARG, which constitutes an interesting target for the future development of probiotics.

Comparative analysis of the duodenojejunal microbiome with the oral and fecal microbiomes reveals its stronger association with obesity and nutrition

The intestinal microbiota is increasingly recognized as a crucial player in the development and maintenance of various chronic conditions, including obesity and associated metabolic diseases. While most research focuses on the fecal microbiota due to its easier accessibility, the small intestine, as a major site for nutrient sensing and absorption, warrants further investigation to determine its microbiota composition and functions. Here, we conducted a clinical research project in 30 age- and sex-matched participants with (n = 15) and without (n = 15) obesity. Duodenojejunal fluid was obtained by aspiration during endoscopy. Phenotyping included clinical variables related to metabolic status, lifestyle, and psychosocial factors using validated questionnaires. We performed metagenomic analyses of the oral, duodenojejunal, and fecal microbiome, alongside metabolomic data from duodenojejunal fluid and feces, integrating these data with clinical and lifestyle information. Our results highlight significant associations between duodenojejunal microbiota composition and usual dietary intake, as well as clinical phenotypes, with larger effect sizes than the associations between these variables and fecal microbiota. Notably, we found that the duodenojejunal microbiota of patients with obesity exhibited higher diversity and showed distinct differences in the abundance of several duodenojejunal microbiota species compared with individuals without obesity. Our findings support the relevance of studying the role of the small intestinal microbiota in the pathogenesis of nutrition-related diseases.

Recipient microbiome-related features predicting metabolic improvement following fecal microbiota transplantation in adults with severe obesity and metabolic syndrome: a secondary analysis of a phase 2 clinical trial

Microbial-based therapeutics in clinical practice are of considerable interest, and a recent study demonstrated fecal microbial transplantation (FMT) followed by dietary fiber supplements improved glucose homeostasis. Previous evidence suggests that donor and recipient compatibility and FMT protocol are key determinants, but little is known about the involvement of specific recipient factors. Using data from our recent randomized placebo-control phase 2 clinical trial in adults with obesity and metabolic syndrome, we grouped participants that received FMT from one of 4 donors with either fiber supplement into HOMA-IR responders (n = 21) and HOMA-IR non-responders (n = 8). We further assessed plasma bile acids using targeted metabolomics and performed subgroup analyzes to evaluate the effects of recipient parameters and gastrointestinal factors on microbiota engraftment and homeostatic model assessment of insulin resistance (HOMA2-IR) response. The baseline fecal microbiota composition at genus level of recipients could predict the improvements in HOMA2-IR at week 6 (ROC-AUC = 0.70). Prevotella was identified as an important predictor, with responders having significantly lower relative abundance than non-responders (p = .02). In addition, recipients displayed a highly individualized degree of microbial engraftment from donors. Compared to the non-responders, the responders had significantly increased bacterial richness (Chao1) after FMT and a more consistent engraftment of donor-specific bacteria ASVs (amplicon sequence variants) such as Faecalibacillus intestinalis (ASV44), Roseburia spp. (ASV103), and Christensenellaceae spp. (ASV140) (p < .05). Microbiota engraftment was strongly associated with recipients' factors at baseline including initial gut microbial diversity, fiber and nutrient intakes, inflammatory markers, and bile acid derivative levels. This study identified that responders to FMT therapy had a higher engraftment rate in the transplantation of specific donor-specific microbes, which were strongly correlated with insulin sensitivity improvements. Further, the recipient baseline gut microbiota and related factors were identified as the determinants for responsiveness to FMT and fiber supplementation. The findings provide a basis for the development of precision microbial therapeutics for the treatment of metabolic syndrome.

Effect of Bariatric Surgery on Gut Microbiota: A Scientometric Analysis

Objective

To perform a bibliometric analysis of the scientific production related to intestinal microbiota and bariatric surgery between January 2016 and December 2022.

Materials and Methods

A bibliographic search was performed in the Scopus database to identify published papers. Free and controlled terms (MeSH and Emtree) were used. The information collected was analyzed with SciVal.

Results

A total of 518 published papers were included in the analysis. Carel Le Roux was the author with the highest scientific production; however, Edi Prifti had the highest impact. French National Institute of Health and Medical Research (Institut national de la santé et de la recherche médicale) was the institution with the highest number of published articles. Six of the 10 institutions with the highest production were in France, yet the United States had the highest volume of scientific production in this research topic. Most papers were published in first quartile journals. Articles with international collaboration had the highest impact. There is a sustained increase in the number of publications since 2019.

Conclusions

The study found that the vast majority of research on gut microbiota changes following bariatric surgery are conducted in the United States and European countries. In addition, the sustained increase in production coupled with the articles being published in high-quality journals and having good citation impact are indictors of the current interest in this research field.

Upper small intestine microbiome in obesity and related metabolic disorders: A new field of investigation

The study of the gut microbiome holds great promise for understanding and treating metabolic diseases, as its functions and derived metabolites can influence the metabolic status of the host. While research on the fecal microbiome has provided valuable insights, it tells us only part of the story. This limitation arises from the substantial variations in microorganism distribution throughout the gastrointestinal tract due to changes in physicochemical conditions. Thus, relying solely on the fecal microbiome may not be sufficient to draw comprehensive conclusions about metabolic diseases. The proximal part of the small intestine, particularly the jejunum, indeed, serves as the crucial site for digestion and absorption of nutrients, suggesting a potential role of its microbiome in metabolic regulation. Unfortunately, it remains relatively underexplored due to limited accessibility. This review presents current evidence regarding the relationships between the microbiome in the upper small intestine and various phenotypes, focusing on obesity and type 2 diabetes, in both humans and rodents. Research on humans is still limited with variability in the population and methods used. Accordingly, to better understand the role of the whole gut microbiome in metabolic diseases, studies exploring the human microbiome in different niches are needed.

Nonalcoholic Fatty Liver Disease and the Intestinal Microbiome: An Inseparable Link

Nonalcoholic fatty liver disease (NAFLD) particularly affects patients with type 2 diabetes and obesity. The incidence of NAFLD has increased significantly over the last decades and is now pandemically across the globe. It is a complex systemic disease comprising hepatic lipid accumulation, inflammation, lipotoxicity, gut dysbiosis, and insulin resistance as main features and with the potential to progress to cirrhosis and hepatocellular carcinoma (HCC). In numerous animal and human studies the gut microbiota plays a key role in the pathogenesis of NAFLD, NAFLD-cirrhosis and NAFLD-associated HCC. Lipotoxicity is the driver of inflammation, insulin resistance, and liver injury. Likewise, western diet, obesity, and metabolic disorders may alter the gut microbiota, which activates innate and adaptive immune responses and fuels hereby hepatic and systemic inflammation. Indigestible carbohydrates are fermented by the gut microbiota to produce important metabolites, such as short-chain fatty acids and succinate. Numerous animal and human studies suggested a pivotal role of these metabolites in the progression of NAFLD and its comorbidities. Though, modification of the gut microbiota and/or the metabolites could even be beneficial in patients with NAFLD, NAFLD-cirrhosis, and NAFLD-associated HCC. In this review we collect the evidence that exogenous and endogenous hits drive liver injury in NAFLD and propel liver fibrosis and the progressing to advanced disease stages. NAFLD can be seen as the product of a complex interplay between gut microbiota, the immune response and metabolism. Thus, the challenge will be to understand its pathogenesis and to develop new therapeutic strategies.

Human metabolism and body composition: prospects for novel studies

CONTEXT

Most articles on gut microbiota argue the importance of body composition assessment in patients; however, body composition assessments are fragile (ie, with methodological limitations) in the most recent studies.

OBJECTIVE

To present two suggestions for further research using the human body composition assessment.

METHODS

The methods used in this study are based on a Pinto et al article published in Nutrition Reviews.

DATA EXTRACTION

On the basis of data.

obtained from the PubMed, SCOPUS, LILACS, and Web of Science databases, Pinto et al provided a current survey of intermittent fasting protocols and an understanding of the outcomes to date in terms of the profile of the intestinal microbiota in obese organisms.

DATA ANALYSIS

Of the 82 original articles identified from the databases, 35 were eliminated because of duplication and 32 were excluded for not meeting the inclusion criteria. Two additional articles found in a new search were added, yielding a total of 17 studies to be included in this review. Among the protocols, alternate-day fasting and time-restricted feeding were the most common, and they were shown to have different mechanisms of metabolic signaling. Time-restricted feeding influences body mass control and biochemical parameters by regulating the circadian system and improving satiety control systems by acting on leptin secretion. In contrast, alternate-day fasting leads to a reduction of ±75% of all energy consumption regardless of dietary composition, in addition to promoting hormonal adjustments that promote body mass control. Furthermore, both protocols could remodel the intestinal microbiota by changing the Firmicutes to Bacteroidetes ratio and increasing the abundance of strains such as Lactobacillus spp. and Akkermansia that have a protective effect on metabolism against the effects of body mass gain.

CONCLUSION

Changes in adipose tissue (eg, body mass loss, control, gain) should be interpreted via the sum of skinfolds in absolute values, waist perimeter, and patients' body proportionality, because fat is just a fraction of the adipocyte (lipid).

Distinctive patterns of sulfide- and butyrate-metabolizing bacteria after bariatric surgery: potential implications for colorectal cancer risk

Despite improved cardiometabolic outcomes following bariatric surgery, its long-term impact on colorectal cancer (CRC) risk remains uncertain. In parallel, the influence of bariatric surgery on the host microbiome and relationships with disease outcomes is beginning to be appreciated. Therefore, we investigated the impact of Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) on the patterns of sulfide-reducing and butyrate-producing bacteria, which are hypothesized to modulate CRC risk after bariatric surgery. In this single-center, cross-sectional study, we included 15 pre-surgery subjects with severe obesity and patients who are at a median (range) of 25.6 (9.9-46.5) months after RYGB (n = 16) or VSG (n = 10). The DNA abundance of fecal bacteria and enzymes involved in butyrate and sulfide metabolism were identified using metagenomic sequencing. Differences between pre-surgery and post-RYGB or post-VSG cohorts were quantified using the linear discriminant analysis (LDA) effect size (LEfSe) method. Our sample was predominantly female (87%) with a median (range) age of 46 (23-71) years. Post-RYGB and post-VSG patients had a higher DNA abundance of fecal sulfide-reducing bacteria than pre-surgery controls (LDA = 1.3-4.4, p < .05). The most significant enrichments were for fecal E. coli, Acidaminococcus and A. finegoldii after RYGB, and for A. finegoldii, S. vestibularis, V. parvula after VSG. As for butyrate-producing bacteria, R. faecis was more abundant, whereas B. dentium and A. hardus were lower post-RYGB vs. pre-surgery. B. dentium was also lower in post-VSG vs. pre-surgery. Consistent with these findings, our analysis showed a greater enrichment of sulfide-reducing enzymes after bariatric surgery, especially RYGB, vs. pre-surgery. The DNA abundance of butyrate-producing enzymes was lower post-RYGB. In conclusion, the two most used bariatric surgeries, RYGB and VSG, are associated with microbiome patterns that are potentially implicated in CRC risk. Future studies are needed to validate and understand the impact of these microbiome changes on CRC risk after bariatric surgery.

Roux-en-Y gastric bypass induces hepatic transcriptomic signatures and plasma metabolite changes indicative of improved cholesterol homeostasis

BACKGROUND & AIMS

Roux-en-Y gastric bypass (RYGB), the most effective surgical procedure for weight loss, decreases obesity and ameliorates comorbidities, such as non-alcoholic fatty liver (NAFLD) and cardiovascular (CVD) diseases. Cholesterol is a major CVD risk factor and modulator of NAFLD development, and the liver tightly controls its metabolism. How RYGB surgery modulates systemic and hepatic cholesterol metabolism is still unclear.

METHODS

We studied the hepatic transcriptome of 26 patients with obesity but not diabetes before and 1 year after undergoing RYGB. In parallel, we measured quantitative changes in plasma cholesterol metabolites and bile acids (BAs).

RESULTS

RYGB surgery improved systemic cholesterol metabolism and increased plasma total and primary BA levels. Transcriptomic analysis revealed specific alterations in the liver after RYGB, with the downregulation of a module of genes implicated in inflammation and the upregulation of three modules, one associated with BA metabolism. A dedicated analysis of hepatic genes related to cholesterol homeostasis pointed towards increased biliary cholesterol elimination after RYGB, associated with enhancement of the alternate, but not the classical, BA synthesis pathway. In parallel, alterations in the expression of genes involved in cholesterol uptake and intracellular trafficking indicate improved hepatic free cholesterol handling. Finally, RYGB decreased plasma markers of cholesterol synthesis, which correlated with an improvement in liver disease status after surgery.

CONCLUSIONS

Our results identify specific regulatory effects of RYGB on inflammation and cholesterol metabolism. RYGB alters the hepatic transcriptome signature, likely improving liver cholesterol homeostasis. These gene regulatory effects are reflected by systemic post-surgery changes of cholesterol-related metabolites, corroborating the beneficial effects of RYGB on both hepatic and systemic cholesterol homeostasis.

IMPACT AND IMPLICATIONS

Roux-en-Y gastric bypass (RYGB) is a widely used bariatric surgery procedure with proven efficacy in body weight management, combatting cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). RYGB exerts many beneficial metabolic effects, by lowering plasma cholesterol and improving atherogenic dyslipidemia. Using a cohort of patients undergoing RYGB, studied before and 1 year after surgery, we analyzed how RYGB modulates hepatic and systemic cholesterol and bile acid metabolism. The results of our study provide important insights on the regulation of cholesterol homeostasis after RYGB and open avenues that could guide future monitoring and treatment strategies targeting CVD and NAFLD in obesity.

Calorie restriction outperforms bariatric surgery in a murine model of obesity and triple-negative breast cancer

Obesity promotes triple-negative breast cancer (TNBC), and effective interventions are urgently needed to break the obesity-TNBC link. Epidemiologic studies indicate that bariatric surgery reduces TNBC risk, while evidence is limited or conflicted for weight loss via low-fat diet (LFD) or calorie restriction (CR). Using a murine model of obesity-driven TNBC, we compared the antitumor effects of vertical sleeve gastrectomy (VSG) with LFD, chronic CR, and intermittent CR. Each intervention generated weight and fat loss and suppressed tumor growth relative to obese mice (greatest suppression with CR). VSG and CR regimens exerted both similar and unique effects, as assessed using multiomics approaches, in reversing obesity-associated transcript, epigenetics, secretome, and microbiota changes and restoring antitumor immunity. Thus, in a murine model of TNBC, bariatric surgery and CR each reverse obesity-driven tumor growth via shared and distinct antitumor mechanisms, and CR is superior to VSG in reversing obesity's procancer effects.