Differential composition of gut microbiota among healthy volunteers, morbidly obese patients and post-bariatric surgery patients

Analysis of microbiota profile and nutritional status in male professional football players

BACKGROUND

The interest in the effect of gut microbiota on athlete health has increased in recent years. Available data indicate a relationship between gut microbiota composition and physical activity, suggesting that changes in the microbiota may contribute to the host's physical performance. Studies show that leaky gut syndrome is highly correlated with upper respiratory infections and gastrointestinal disorders in endurance sports. This study aims to reveal the relationship between microbiota profiles, and the nutritional status of football players who perform endurance exercises.

METHODS

Twenty male professional football players playing in one of the Turkish Football Federation Second League clubs participated in the study. Fecal samples were collected and stored at -86 °C, and the fecal microbiota was analyzed through 16s rRNA gene sequencing. The body composition of the football players was measured using a bioelectrical impedance analyzer. In addition, the 3-day food intake of the participants was recorded with the help of a dietitian.

RESULTS

In the microbiota of football players, four phyla, 10 genera, and four species with densities above 1% were found. Body fat percentage was observed to be negatively correlated with the species of Faecalibacterium prausnitzii and Bacteroides vulgatus and the genus of Faecalibacterium (P<0.05). Considering the nutritional status, the fat intake was found to be positively correlated with Actinobacteria and Blautia coccoides; energy and fiber intake with Prevotella and Prevotella copri (P<0.05). In addition, there was a negative correlation between carbohydrate intake and Faecalibacterium (P<0.05).

CONCLUSIONS

Our study is the first to reveal the microbiota profile of professional Turkish football players. It was found that football players' nutritional status and anthropometric measurements of are significantly related to phylum, genus and species ranks in the microbiota. These results support the bidirectional interaction between microbiota and sports. The relationship between microbiota and sports health/performance is thought to be further clarified with future studies.

A specific gut microbiota signature is associated with an enhanced GLP-1 and GLP-2 secretion and improved metabolic control in patients with type 2 diabetes after metabolic Roux-en-Y gastric bypass

Objective

To determine changes in incretins, systemic inflammation, intestinal permeability and microbiome modifications 12 months after metabolic RYGB (mRYGB) in patients with type 2 diabetes (T2D) and their relationship with metabolic improvement.

Materials and methods

Prospective single-center non-randomized controlled study, including patients with class II-III obesity and T2D undergoing mRYGB. At baseline and one year after surgery we performed body composition measurements, biochemical analysis, a meal tolerance test (MTT) and lipid test (LT) with determination of the area under the curve (AUC) for insulin, C-peptide, GLP-1, GLP-2, and fasting determinations of succinate, zonulin, IL-6 and study of gut microbiota.

Results

Thirteen patients aged 52.6 ± 6.5 years, BMI 39.3 ± 1.4 kg/m2, HbA1c 7.62 ± 1.5% were evaluated. After mRYGB, zonulin decreased and an increase in AUC after MTT was observed for GLP-1 (pre 9371 ± 5973 vs post 15788 ± 8021 pM, P<0.05), GLP-2 (pre 732 ± 182 vs post 1190 ± 447 ng/ml, P<0.001) and C- peptide, as well as after LT. Species belonging to Streptococaceae, Akkermansiacea, Rickenellaceae, Sutterellaceae, Enterobacteriaceae, Oscillospiraceae, Veillonellaceae, Enterobacterales_uc, and Fusobacteriaceae families increased after intervention and correlated positively with AUC of GLP-1 and GLP-2, and negatively with glucose, HbA1c, triglycerides and adiposity markers. Clostridium perfringens and Roseburia sp. 40_7 behaved similarly. In contrast, some species belonging to Lachnospiraceae, Erysipelotricaceae, and Rumnicocaceae families decreased and showed opposite correlations. Higher initial C-peptide was the only predictor for T2D remission, which was achieved in 69% of patients.

Conclusions

Patients with obesity and T2D submitted to mRYGB show an enhanced incretin response, a reduced gut permeability and a metabolic improvement, associated with a specific microbiota signature.

Changes in the Gut Microbiota Composition and Their Relation to Dietary Intake After Bariatric Surgery

PURPOSE

Prior studies have demonstrated that both dietary components and bariatric surgery modify the gut microbiota's composition. However, there is a scarcity of research that has examined the relationship between post-surgical dietary intake and changes in the gut microbiota. The aim of this study was to assess changes in gut microbiota following bariatric surgery and examine their association with postoperative dietary intake.

MATERIALS AND METHODS

The present study involved a sample of 42 adult women who were potential candidates for bariatric surgery, i.e., laparoscopic Roux-en-Y gastric bypass (LRYGB) or sleeve gastrectomy (LSG). The assessment of dietary intake was conducted through the use of three-day food records, both at baseline and six months following the surgical procedure. The gut microbiota was determined through the detection of 16S ribosomal RNA (16S rRNA) gene sequencing.

RESULTS

After six months, a significant increase in abundance of Firmicutes (P = 0.01), Bifidobacterium (P = 0.01), and Ruminococcus (P = 0.04) in the LSG group was found. In contrast to the observed rise in Enterobacteria (P = 0.02) levels in the LRYGB group, no significant changes were detected in the composition of other gut microbiota over the 6-month monitoring period subsequent to LRYGB. The results of our study indicate that there is not a statistically significant relationship between dietary consumption and changes in the composition of the gut microbiota in individuals who have undergone LRYGB and LSG.

CONCLUSION

Our findings suggest that there may not be a significant correlation between dietary intake following LRYGB and LSG, and the observed alterations in the gut microbiota during a six-month period of observation. Nevertheless, it is important to acknowledge that the sample size utilized in our study was limited, potentially leading to reduced statistical power and the possibility of yielding findings that do not accurately reflect reality.

Profiles and diagnostic value of intestinal microbiota in schizophrenia patients with metabolic syndrome

Aims/hypothesis

It is widely thought that the intestinal microbiota plays a significant role in the pathogenesis of metabolic disorders. However, the gut microbiota composition and characteristics of schizophrenia patients with metabolic syndrome (MetS) have been largely understudied. Herein, we investigated the association between the metabolic status of mainland Chinese schizophrenia patients with MetS and the intestinal microbiome.

Methods

Fecal microbiota communities from 115 male schizophrenia patients (57 with MetS and 58 without MetS) were assessed by 16S ribosomal RNA gene sequencing. We assessed the variations of gut microbiome between both groups and explored potential associations between intestinal microbiota and parameters of MetS. In addition, the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) based on the KEGG database was used to predict the function of intestinal microbiota. We also conducted Decision Tree Analysis to develop a diagnostic model for the MetS in patients with schizophrenia based on the composition of intestinal microbiota.

Results

The fecal microbial diversity significantly differed between groups with or without MetS (α-diversity (Shannon index and Simpson index): p=0.0155, p=0.0089; β-diversity: p=0.001). Moreover, the microbial composition was significantly different between the two groups, involving five phyla and 38 genera (p<0.05). In addition, a significant correlation was observed between the metabolic-related parameters and abundance of altered microbiota including HDL-c (r2 = 0.203, p=0.0005), GLU (r2 = 0.286, p=0.0005) and WC (r2 = 0.061, p=0.037). Furthermore, KEGG pathway analysis showed that 16 signaling pathways were significantly enriched between the two groups (p<0.05). Importantly, our diagnostic model based on five microorganisms established by decision tree analysis could effectively distinguish between patients with and without MetS (AUC = 0.94).

Conclusions/interpretation

Our study established the compositional and functional characteristics of intestinal microbiota in schizophrenia patients with MetS. These new findings provide novel insights into a better understanding of this disease and provide the theoretical basis for implementing new interventional therapies in clinical practice.

Personalized Approach for Obese Patients Undergoing Endoscopic Sleeve Gastroplasty

Obesity is a chronic, relapsing disease representing a major global health problem in the 21st century. Several etiologic factors are involved in its pathogenesis, including a Western hypercaloric diet, sedentariness, metabolic imbalances, genetics, and gut microbiota modification. Lifestyle modifications and drugs often fail to obtain an adequate and sustained weight loss. To date, bariatric surgery (BS) is the most effective treatment, but only about 1% of eligible patients undergo BS, partly because of its negligible morbidity and mortality. Endoscopic sleeve gastroplasty (ESG) is a minimally invasive, endoscopic, bariatric procedure, which proved to be safe and effective. In this review, we aim to examine evidence supporting the role of a personalized and multidisciplinary approach, guided by a multidisciplinary team (MDT), for obese patients undergoing ESG, from patient selection to long-term follow-up. The cooperation of different health professionals, including an endocrinologist and/or obesity medicine physician, a bariatric surgeon, an endoscopist experienced in bariatrics, a registered dietitian, an exercise specialist, a behaviour coach, a psychologist, and a nurse or physician extender, aims to induce radical and sustained lifestyle changes. We also discussed the relationship between gut microbiota and outcomes after bariatric procedures, speculating that the characterization of gut microbiota before and after ESG may help develop new tools, including probiotics, to optimize weight loss outcomes.

Shifts in gut microbiota and their metabolites induced by bariatric surgery. Impact of factors shaping gut microbiota on bariatric surgery outcomes

Evidence suggests that bariatric surgery alters gut microbiota, although its impact at compositional and functional level is not well described. In this review, the most relevant findings, mainly described in Roux-en-Y gastric bypass and sleeve gastrectomy, are outlined. Although the number of studies has increased in the last years, conclusive assertions cannot be elaborated. An issue to address is to know the influence of these alterations on host metabolism and the contribution of gut microbiota derived metabolites. New lines of research have been focusing on analysing gut microbiota functionality rather than evaluating changes at compositional level, and the functions of gut microbiota metabolites in host metabolism, what will bring more relevant information about the influence of gut microbiota in bariatric surgery outcomes. Personalized medicine, because of the predictive value of gut microbiota, is another promising field. The possibility of a specific gut microbiota pattern that could predict type 2 diabetes remission or weight loss failure after bariatric surgery is a matter of great interest. However, little is known about how gut microbiota manipulation could contribute to the beneficial effects of bariatric surgery. Peri-operative antibiotics prophylaxis or probiotic supplementation early after surgery, are strategies barely studied so far, and could constitute a novel tool in the management of weight loss and metabolic profile improvement after surgery.

Alterations of Gut Bacteria in Hirschsprung Disease and Hirschsprung-Associated Enterocolitis

Hirschsprung-associated enterocolitis (HAEC) is a common life-threatening complication of Hirschsprung disease (HSCR). It has been proposed that gut microbiota, which have an essential role in gut-homeostasis, are associated with HAEC. Recent studies demonstrated an increase in alpha diversity of fecal microbiota over time in HSCR mice and a decrease in diversity after surgery. In addition, clinical studies have reported a reduction in bacterial richness in HSCR children after surgery. Some studies revealed a difference in microbiota between the proximal ganglionic and distal aganglionic intestine and found a difference in bacterial character between fecal and colonic specimens. HAEC studies found an increase in Proteobacteria, especially Escherichia and Enterobacteriaceae, with a decrease in Firmicutes and Bifidobacterium in HAEC patients. However, the direction of alpha diversity in HAEC patients is still controversial. The self-comparison of microbiota in treatment periods suggested that probiotics might improve gut dysbiosis and decrease the frequency of enterocolitis, but some reported contradictory findings. This review comprehensively summarizes and discusses key findings from animal and clinical data of the distinct microbiome associated with HCSR and the association of gut dysbiosis with the development of HAEC. This information should be useful in the establishment of novel interventions to improve gut dysbiosis and prevent enterocolitis in HSCR patients.

Sinomenine hydrochloride ameliorates dextran sulfate sodium-induced colitis in mice by modulating the gut microbiota composition whilst suppressing the activation of the NLRP3 inflammasome

Sinomenine is a pure alkaloid that can be isolated from the root of Sinomenium acutum and has been found to exert anti-inflammatory and immunosuppressive effects. The present study investigated the effects of sinomenine hydrochloride (SIN) on inflammation and the gut microbiota composition in the colon of mouse models of dextran sulfate sodium (DSS)-induced colitis. DSS-induced mice colitis was established by treating the mice with drinking water containing 3% (w/v) DSS for 7 days. The disease activity index of each mouse was calculated on a daily basis. All mice were sacrificed on day 11, then the weight of their spleen and length of their colons were measured. The histological analysis was measured by hematoxylin-eosin staining. Oral administration of SIN (100 mg/kg/day) attenuated the DSS-induced increases in the disease activity indices and spleen indices, DSS-induced shortening of the colon length and histological damage. In addition, reverse transcription-quantitative PCR data showed that SIN treatment effectively regulated the expression of inflammatory mediators, specifically by suppressing the expression of proinflammatory gene (TNF-α, IL-6 and inducible nitric oxide synthase) whilst increasing those associated with inhibiting inflammation (IL-10 and arginine 1). Gut microbiota analysis was conducted using 16S ribosomal DNA sequencing. The results revealed that SIN improved bacterial community homeostasis and diversity, which were damaged by DSS. Furthermore, western blotting showed that the activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome was markedly suppressed by SIN treatment. In conclusion, these results indicated that SIN may ameliorate experimental colitis by modulating the gut microbiota composition and suppressing the activation of the NLRP3 inflammasome in mice. Overall, these findings suggested a broad protective effect of SIN in treating inflammatory gut diseases, including ulcerative colitis.

Bariatric procedures and microbiota: patient selection and outcome prediction

Obesity is a major health issue throughout the world and bariatric surgery plays a key role in its management and treatment. The role of microbiota in determining the pathogenesis of obesity has been widely studied, while its role in determining the outcome of bariatric surgery is an emerging issue that will be an outcome in near future studies. Studies on mice first showed the key role of microbiota in determining obesity, highlighting the fat mass increase in mice transplanted with microbiota from fat individuals, as well as the different microbiota composition between mice undergone to low-fat or high-fat diets. This led to characterize the asset of microbiota composition in obesity: increased abundance of Firmicutes, reduced abundance of Bacteroidetes and other taxonomical features. Variations on the composition of gut microbiome have been detected in patients undergone to diet and/or bariatric surgery procedures. Patients undergone to restricting diets showed lower level of trimethylamine N-oxide and other metabolites strictly associated to microbiome, as well as patients treated with bariatric surgery showed, after the procedure, changes in the relative abundance of Bacteroidetes, Firmicutes and other phyla with a role in the pathogenesis of obesity. Eventually, studies have been led about the effects that the modification of microbiota could have on obesity itself, mainly focusing on elements like fecal microbiota transplantation and probiotics such as inulin. This series of studies and considerations represent the first step in order to select patients eligible to bariatric surgery and to predict their outcome.

The Gut/Lung Microbiome Axis in Obesity, Asthma, and Bariatric Surgery: A Literature Review

Mounting evidence suggests that obesity, parameters of metabolic syndrome, and asthma are significantly associated. Interestingly, these conditions are also associated with microbiome dysbiosis, notably in the airway microbiome for patients with asthma and in the gut microbiome for patients with obesity and/or metabolic syndrome. Considering that improvements in asthma control, lung function, and airway hyperresponsiveness are often reported after bariatric surgery, this review investigated the potential role of bacterial gut and airway microbiome changes after bariatric surgery in ameliorating asthma symptoms. Rapid and persistent gut microbiota alterations were reported following surgery, some of which can be sustained for years. The gut microbiome is thought to modulate airway cellular responses via short-chain fatty acids and inflammatory mediators, such that increased propionate and butyrate levels following surgery may aid in reducing asthma symptoms. In addition, increased prevalence of Akkermansia muciniphila after Roux-en-Y gastric bypass and sleeve gastrectomy may confer protection against airway hyperreactivity and inflammation. Metabolic syndrome parameters also improved following bariatric surgery, and whether weight-loss-independent metabolic changes affect airway processes and asthma pathobiology merits further research. Fulfilling knowledge gaps outlined in this review could facilitate the development of new therapeutic options for patients with obesity and asthma.

Significance of intestinal microbiota in implementing metabolic effects of bariatric surgery

Bariatric surgery is among successful methods of obesity treatment, with effects going beyond weight reduction alone, but rather involving improved glucose tolerance, along with control or remission of the type 2 diabetes mellitus. The precise mechanisms causing metabolic effects of bariatric surgery are not fully elucidated, even though substantial evidence suggest that they include changes in the gut microbiota, bile acid homeostasis, and the close interactions of these factors. Intestinal microflora is directly involved in the energy metabolism of a host human. Obesity and type 2 diabetes mellitus are associated with certain changes in the species composition and diversity of intestinal microflora, which are considered important factors in the development and progression of these ailments. Bariatric surgery leads to significant and persistent changes in the composition of the intestinal microbiota, often bringing it closer to the characteristics of the microbiota of an average person with a normal weight. An important role in implementing the metabolic effects of bariatric surgery, primarily in the improvement of glucose metabolism, belongs to postoperative changes in homeostasis of bile acids. These changes imply close metabolism. Moreover, changes in the bile acid metabolism after bariatric surgery affect the microbiota of the host. Further study of these relationships would clarify the mechanisms underlying metabolic surgery, make it more predictable, targeted and controlled, as well as open new therapeutic targets in the treatment of obesity and associated conditions.

Diet- and sex-related changes of gut microbiota composition and functional profiles after 4 months of weight loss intervention

PURPOSE

Obesity has been related to intestinal dysbiosis and the modification of gut microbiota composition by dietary strategies becomes a promising strategy to help manage obesity. The aim of the current study was to evaluate the effect of two weight-loss diets on the composition and functional profile of gut microbiota.

METHODS

55 men and 124 women with BMI > 25 kg/m² were randomly assigned to moderately high-protein (MHP) or low-fat (LF) diet. Differences in fecal bacteria abundance (based on 16 s rRNA sequencing) between before and after 4 months of calorie restriction was analyzed using EdgeR tool in MicrobiomeAnalyst platform. Bacterial functional profile was predicted using Tax4Fun and metagenomeSeq analysis. Significant KEGG Orthology (KO) terms were selected for the metabolomic study using chromatography.

RESULTS

After the intervention, MHP-men showed a significant decrease in Negativicutes, Selenomonadales, Dielma and Dielma fastidiosa. LF-men showed a significant increase in Bacilli, Lactobacillales, Christensenellaceae, Peptococcaceae, and Streptococcaceae, Peptococcus, Streptococcus and Christensenella, Duncaniella dubosii_CP039396_93.49%, Roseburia sp_AB744234_98.96% and Alistipes inops_KJ572413_99.57%. MHP-women increased Pasteurellales, Phascolarctobacterium succinatutens, Ruthenibacterium lactatiformans_LR215981_99.55% and decreased in Phascolarctobacterium succinatutens_NR112902_99.56%. Finally, LF-women presented a significant decrease in Bacteroides clarus and Erysipelothrix inopinata_CP060715_84.4%. Surprisingly, no matching bacterial changes were found between these four groups. A total of 42 KO, 10 metabolic pathways and 107 related metabolites related were found implicated in these bacterial changes. Seven metabolites were confirmed in plasma.

CONCLUSION

Weight-loss-related-changes in gut microbiome composition and the functional profile occur in a sex- and diet-related manner, showing that women and men could differentially benefit from the consumption of MHP and LF diets.

TRIAL REGISTRATION

NCT02737267, 10th March 2016 retrospectively registered.

A microbial signature following bariatric surgery is robustly consistent across multiple cohorts

Bariatric surgery induces significant shifts in the gut microbiota which could potentially contribute to weight loss and metabolic benefits. The aim of this study was to characterize a microbial signature following Roux-en-Y Gastric bypass (RYGB) surgery using novel and existing gut microbiota sequence data. We generated 16S rRNA gene and metagenomic sequences from fecal samples from patients undergoing RYGB surgery (n = 61 for 16S rRNA gene and n = 135 for metagenomics) at pre-surgical baseline and one, six, and twelve-month post-surgery. We compared these data with three smaller publicly available 16S rRNA gene and one metagenomic datasets from patients who also underwent RYGB surgery. Linear mixed models and machine learning approaches were used to examine the presence of a common microbial signature across studies. Comparison of our new sequences with previous longitudinal studies revealed strikingly similar profiles in both fecal microbiota composition (r = 0.41 ± 0.10; p < .05) and metabolic pathways (r = 0.70 ± 0.05; p < .001) early after surgery across multiple datasets. Notably, Veillonella, Streptococcus, Gemella, Fusobacterium, Escherichia/Shigella, and Akkermansia increased after surgery, while Blautia decreased. Machine learning approaches revealed that the replicable gut microbiota signature associated with RYGB surgery could be used to discriminate pre- and post-surgical samples. Opportunistic pathogen abundance also increased post-surgery in a consistent manner across cohorts. Our study reveals a robust microbial signature involving many commensal and pathogenic taxa and metabolic pathways early after RYGB surgery across different studies and sites. Characterization of the effects of this robust microbial signature on outcomes of bariatric surgery could provide insights into the development of microbiome-based interventions for predicting or improving outcomes following surgery.

Gut Microbiota, Probiotics and Psychological States and Behaviors after Bariatric Surgery-A Systematic Review of Their Interrelation

The gastrointestinal (GI) microbiota plays an important role in health and disease, including brain function and behavior. Bariatric surgery (BS) has been reported to result in various changes in the GI microbiota, therefore demanding the investigation of the impact of GI microbiota on treatment success. The goal of this systematic review was to assess the effects of BS on the microbiota composition in humans and other vertebrates, whether probiotics influence postoperative health, and whether microbiota and psychological and behavioral factors interact. A search was conducted using PubMed and Web of Science to find relevant studies with respect to the GI microbiota and probiotics after BS, and later screened for psychological and behavioral parameters. Studies were classified into groups and subgroups to provide a clear overview of the outcomes. Microbiota changes were further assessed for whether they were specific to BS in humans through the comparison to sham operated controls in other vertebrate studies. Changes in alpha diversity appear not to be specific, whereas dissimilarity in overall microbial community structure, and increases in the abundance of the phylum Proteobacteria and Akkermansia spp. within the phylum Verrucomicrobia after surgery were observed in both human and other vertebrates studies and may be specific to BS in humans. Human probiotic studies differed regarding probiotic strains and dosages, however it appeared that probiotic interventions were not superior to a placebo for quality of life scores or weight loss after BS. The relationship between GI microbiota and psychological diseases in this context is unclear due to insufficient available data.

From obesity through gut microbiota to cardiovascular diseases: a dangerous journey

The co-existence of humans and gut microbiota started millions of years ago. Until now, a balance gradually developed between gut bacteria and their hosts. It is now recognized that gut microbiota are key to form adequate immune and metabolic functions and, more in general, for the maintenance of good health. Gut microbiota are established before birth under the influence of maternal nutrition and metabolic status, which can impact the future metabolic risk of the offspring in terms of obesity, diabetes, and cardiometabolic disorders during the lifespan. Obesity and diabetes are prone to disrupt the gut microbiota and alter the gut barrier permeability, leading to metabolic endotoxaemia with its detrimental consequences on health. Specific bacterial sequences are now viewed as peculiar signatures of the metabolic syndrome across life stages in each individual, and are linked to pathogenesis of cardiovascular diseases (CVDs) via metabolic products (metabolites) and immune modulation. These mechanisms have been linked, in association with abnormalities in microbial richness and diversity, to an increased risk of developing arterial hypertension, systemic inflammation, nonalcoholic fatty liver disease, coronary artery disease, chronic kidney disease, and heart failure. Emerging strategies for the manipulation of intestinal microbiota represent a promising therapeutic option for the prevention and treatment of CVD especially in individuals prone to CV events.

Gut Microbiota Profiles of Treated Metabolic Syndrome Patients and their Relationship with Metabolic Health

Metabolic syndrome (MetS) has become a worldwide health issue. Recent studies reveal that the human gut microbiota exerts a significant role in the pathogenesis of this disease. While drug treatments may greatly improve metabolic symptoms, little is known about the gut microbiota composition of these treated MetS patients. This study aimed to characterize the gut microbiota composition of treated-MetS patients and analyse the possibility of using gut microbiota as an indicator of metabolic conditions. 16S rRNA metagenomic sequencing approach was used to profile gut microbiota of 111 treated MetS patients from The Cohort of patients at a high Risk of Cardiovascular Events (CORE)-Thailand registry. Our results show that the gut microbiota profiles of MetS patients are diverse across individuals, but can be classified based on their similarity into three groups or enterotypes. We also showed several associations between species abundance and metabolic parameters that are enterotype specific. These findings suggest that information on the gut microbiota can be useful for assessing treatment options for MetS patients. In addition, any correlations between species abundance and human properties are likely specific to each microbial community.

A 5-Year Follow-up in Children and Adolescents Undergoing One-Anastomosis Gastric Bypass (OAGB) at a European IFSO Excellence Center (EAC-BS)

BACKGROUND

The children and adolescent population with obesity has increased worldwide, both in developing areas and in developed countries. Consequently, the prevalence of morbid obesity among this population has also increased, leading to an exponential growth of bariatric approaches in this population. Many surgeons fear eventual nutritional sequelae after malabsorptive approaches and prefer restrictive or mixed procedures.

METHODS

A retrospective review of all the morbidly obese patients between 13 and 19 years, undergoing a one-anastomosis gastric bypass (OAGB) as bariatric procedure between 2004 and 2012, was performed.

RESULTS

A total of 39 patients were included, 8 males (20.5%) and 31 females (79.5%), with a mean age of 17.8 ± 2 years (range 13-19 years). Mean preoperative weight was 114.3 ± 20.4 kg and mean BMI 42.2 ± 5.9 kg/m². Preoperative comorbidities include only type 2 diabetes mellitus (T2DM) in 7.9% of the patients, hypertension in 10.3%, and dyslipidemia in 23.1%. Five years after surgery, mean BMI was 25.9 ± 5.3 kg/m² and total weight loss 32.1 ± 15.7%. Remission rate of T2DM, hypertension and dyslipidemia was 100%. All the patients received multivitamin and vitamin D supplementation. Anemia secondary to iron deficiency occurred in one female, requiring intravenous iron supplementation during 1 year and later on oral supplementation.

CONCLUSIONS

OAGB is a valid alternative for long-term weight loss and remission of comorbidities in childhood and adolescence. No cases of malnutrition or growth disorders were observed.

Microbial Adaptation Due to Gastric Bypass Surgery: The Nutritional Impact

Bariatric surgery leads to sustained weight loss and the resolution of obesity-related comorbidities. Recent studies have suggested that changes in gut microbiota are associated with the weight loss induced by bariatric surgery. Several studies have observed major changes in the microbial composition following gastric bypass surgery. However, there are inconsistencies between the reported alterations in microbial compositions in different studies. Furthermore, it is well established that diet is an important factor shaping the composition and function of intestinal microbiota. However, most studies on gastric bypass have not assessed the impact of dietary intake on the microbiome composition in general, let alone the impact of restrictive diets prior to bariatric surgery, which are recommended for reducing liver fat content and size. Thus, the relative impact of bariatric surgery on weight loss and gut microbiota remains unclear. Therefore, this review aims to provide a deeper understanding of the current knowledge of the changes in intestinal microbiota induced by bariatric surgery considering pre-surgical nutritional changes.

Longitudinal changes of microbiome composition and microbial metabolomics after surgical weight loss in individuals with obesity

BACKGROUND

Some of the metabolic effects of bariatric surgery may be mediated by the gut microbiome.

OBJECTIVES

To study the effect of bariatric surgery on changes to gut microbiota composition and bacterial pathways, and their relation to metabolic parameters after bariatric surgery.

SETTINGS

University hospitals in the United States and Spain.

METHODS

Microbial diversity and composition by 16 S rRNA sequencing, putative bacterial pathways, and targeted circulating metabolites were studied in 26 individuals with severe obesity, with and without type 2 diabetes, before and at 3, 6, and 12 months after either gastric bypass or sleeve gastrectomy.

RESULTS

Bariatric surgery tended to increase alpha diversity, and significantly altered beta diversity, microbiota composition, and function up to 6 months after surgery, but these changes tend to regress to presurgery levels by 12 months. Twelve of 15 bacterial pathways enriched after surgery also regressed to presurgery levels at 12 months. Network analysis identified groups of bacteria significantly correlated with levels of circulating metabolites over time. There were no differences between study sites, surgery type, or diabetes status in terms of microbial diversity and composition at baseline and after surgery.

CONCLUSIONS

The association among changes in microbiome with decreased circulating biomarkers of inflammation, increased bile acids, and products of choline metabolism and other bacterial pathways suggest that the microbiome partially mediates improvement of metabolism during the first year after bariatric surgery.

Obesity-Related Epigenetic Changes After Bariatric Surgery

Objective: In recent years, an increasing number of studies have begun focusing on epigenetics as a link between environmental factors and a greater predisposition to the development of obesity and its comorbidities. An important challenge in this field is the evaluation of the possibility of the reversal of obesity-related epigenetic marks by means of therapy to induce weight loss and if the beneficial effects of therapy in reducing obesity are mediated by epigenetic mechanisms. We aimed to offer an outline of the current results regarding to the impact of bariatric surgery on epigenetic regulation, as well as to show if the beneficial effect of this intervention could be mediated by epigenetic mechanisms. Methods: A review of the scientific publications in PubMed was performed by using key words related to obesity, epigenetics and bariatric surgery to provide an update of recent findings in this area of research. The most relevant and recently published articles and abstracts were selected to frame this review. Results: Previous studies have demonstrated the presence of differential DNA methylation after bariatric surgery and the differential expression of non-coding RNAs. Therefore, epigenetic regulation could mediate the benefit of bariatric surgery on body weight and the metabolic disturbances associated with excess body weight, such as insulin resistance, hypertension, and cardiovascular disease. This evidence is relatively new as epigenetic regulation was first evaluated in the obesity field only a few years ago. However, there is an urgent need to perform longitudinal studies to evaluate the capacity of epigenetic marks in the prediction of bariatric surgery response. Conclusions: Bariatric surgery appears to be capable of partially reversing the obesity-related epigenome. The identification of potential epigenetic biomarkers predictive for the success of bariatric surgery may open new doors to personalized therapy for severe obesity.