Conserved shifts in the gut microbiota due to gastric bypass reduce host weight and adiposity

Short-Chain Fatty Acids-A Product of the Microbiome and Its Participation in Two-Way Communication on the Microbiome-Host Mammal Line

PURPOSE OF REVIEW

The review aims to describe short-chain fatty acids (SCFAs) as metabolites of bacteria, their complex influence on whole-body metabolism, and alterations in the SCFA profile in obesity and after bariatric surgery (BS).

RECENT FINDINGS

The fecal profile of SCFAs in obese patients differs from that of lean patients, as well as their gut microbiota composition. In obese patients, a lower diversity of bacteria is observed, as well as higher concentrations of SCFAs in stool samples. Obesity is now considered a global epidemic and bariatric surgery (BS) is an effective treatment for severe obesity. BS affects the structure and functioning of the digestive system, and also alters gut microbiota and the concentration of fecal SCFAs. Generally, after BS, SCFA levels are lower but levels of branched short-chain fatty acids (BSCFAs) are elevated, the effect of which is not fully understood. Moreover, changes in the profile of circulating SCFAs are little known and this is an area for further research. Obesity seems to be inherently associated with changes in the SCFA profile. It is necessary to better understand the impact of BS on microbiota and the metabolome in both feces and blood as only a small percentage of SCFAs are excreted. Further research may allow the development of a personalized therapeutic approach to the BS patient in terms of diet and prebiotic intervention.

Gut microbiome modified by bariatric surgery improves insulin sensitivity and correlates with increased brown fat activity and energy expenditure

Alterations in the microbiome correlate with improved metabolism in patients following bariatric surgery. While fecal microbiota transplantation (FMT) from obese patients into germ-free (GF) mice has suggested a significant role of the gut microbiome in metabolic improvements following bariatric surgery, causality remains to be confirmed. Here, we perform paired FMT from the same obese patients (BMI > 40; four patients), pre- and 1 or 6 months post-Roux-en-Y gastric bypass (RYGB) surgery, into Western diet-fed GF mice. Mice colonized by FMT from patients' post-surgery stool exhibit significant changes in microbiota composition and metabolomic profiles and, most importantly, improved insulin sensitivity compared with pre-RYGB FMT mice. Mechanistically, mice harboring the post-RYGB microbiome show increased brown fat mass and activity and exhibit increased energy expenditure. Moreover, improvements in immune homeostasis within the white adipose tissue are also observed. Altogether, these findings point to a direct role for the gut microbiome in mediating improved metabolic health post-RYGB surgery.

Soda intake influences phenotype, antioxidants and inflammatory status in high protein-fed wistar rats

An increasing population of people, especially young adults who exercise, consume high protein diets along with carbonated drinks. While there are numerous studies on the effect of high protein diets, there is a need to understand how protein diets in combination with carbonated drinks impact physiology. In order to assess these effects on wistar rats' phenotype, antioxidants and inflammatory profiles, 64 wistar rats were divided into dietary groups of 8 male and 8 female animals each. The animals were fed standard diet as control (chow), chow and carbonated soda, a high protein diet (48.1% energy from protein) and a high protein diet with carbonated soda according to their groups. Body measurements, blood glucose levels, serum insulin levels, lipid peroxidation, antioxidant activity, adipokines and inflammatory markers concentrations were all determined. At the end of the study, body measurements, inflammatory markers and adipokine concentration were increased in animals fed the high protein diet and high protein-soda diet. There was a decrease in antioxidant and lipid peroxidation levels in protein fed male and female animals but those fed protein in combination with soda had increased lipid peroxidation levels. In conclusion, high protein diet in combination with carbonated soda impacts physiology differently from a high protein diet alone, and may stimulate weight gain, oxidative stress and HPD-related inflammation in Wistar rats.

Colchicine effects on the gut microbiome in adults with metabolic syndrome

Obesity-induced inflammation plays a substantial role in the development of insulin resistance and type 2 diabetes. The altered gut flora in obesity can also contribute to metabolic dysregulation and systemic inflammation. However, it remains unclear how dysregulation of systemic inflammation in obesity affects the gut microbiome. We hypothesized that colchicine's systemic anti-inflammatory effects in obesity would be associated with improvements in gut microbial diversity. We conducted a secondary analysis of a double-blind randomized placebo-controlled trial, in which 40 adults with obesity, high C-reactive protein (CRP) (≥2.0 mg/L), insulin resistance (homeostatic model of insulin resistance: HOMA-IR ≥2.6 mg/L), and metabolic syndrome (MetS) were randomized to three months of colchicine 0.6 mg or placebo tablets twice daily. Serum and stool samples were collected at baseline and final visit. Gut microbiota composition was characterized from stool DNA by dual-index amplification and sequencing of 16S ribosomal RNA. Pre- and post-intervention stool samples were available for 15 colchicine- and 12 placebo-treated subjects. Circulating high sensitivity CRP (hsCRP), interleukin-6, resistin, white blood count, and neutrophils were significantly decreased in the colchicine arm as compared to placebo. However, changes in stool microbiome alpha diversity, as assessed by the Chao1, Shannon, and Pielou indices, were not significant between groups. Amplicon sequence variant counts were unchanged among all examined phyla or families. Oscillibacter was the only genus to demonstrate even a nominally significant change. Among adults with obesity and MetS, colchicine significantly improved systemic inflammation. However, this anti-inflammatory effect was not associated with significant changes in the gut microbiome. Further studies are warranted to investigate this relationship.

Brazilian guide to nutrition in bariatric and metabolic surgery

PURPOSE

Brazilian nutrition recommendations for bariatric and metabolic surgery aim to provide knowledge, based on scientific evidence, on nutritional practices related to different surgical techniques in the surgical treatment of obesity and metabolic diseases.

MATERIALS AND METHODS

A systematic literature search was carried out with the appropriate MeSH terms using Medline/Pubmed/LiLACS and the Cochrane database, with the established criteria being based on the inclusion of articles according to the degree of recommendation and strength of evidence of the Classification of Recommendations, Evaluation, Development, and Evaluation System (GRADE).

RESULTS

The recommendations that make up this guide were gathered to assist in the individualized clinical practice of nutritionists in the nutritional management of patients with obesity, including nutritional management in the intragastric balloon; pre and postoperative nutritional treatment and supplementation in bariatric and metabolic surgeries (adolescents, adults, elderly, pregnant women, and vegetarians); hypoglycemia and reactive hyperinsulinemia; and recurrence of obesity, gut microbiota, and inflammatory bowel diseases.

CONCLUSION

We believe that this guide of recommendations will play a decisive role in the clinical practice of nutritionists who work in bariatric and metabolic surgery, with its implementation in health services, thus promoting quality and safety in the treatment of patients with obesity. The concept of precision nutrition is expected to change the way we understand and treat these patients.

Forging the microbiome to help us live long and prosper

Aging is often accompanied by an increased risk of an array of diseases spanning the cardiovascular, nervous, and immune systems, among others. Despite remarkable progress in understanding the cellular and molecular mechanisms involved in aging, the role of the microbiome remains understudied. In this Essay, we highlight recent progress towards understanding if and how the microbiome contributes to aging and age-associated diseases. Furthermore, we discuss the need to consider sexually dimorphic phenotypes in the context of aging and the microbiome. We also highlight the broad implications for this emerging area of interdisciplinary research to address long-standing questions about host-microbiome interactions across the life span.

Excess body weight: Novel insights into its roles in obesity comorbidities

Excess body weight is a global health problem due to sedentary lifestyle and unhealthy diet, affecting 2 billion population worldwide. Obesity is a major risk factor for metabolic diseases. Notably, the metabolic risk of obesity largely depends on body weight distribution, of which visceral adipose tissues but not subcutaneous fats are closely associated with obesity comorbidities, including type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular disease and certain types of cancer. Latest multi-omics and mechanistical studies reported the crucial involvement of genetic and epigenetic alterations, adipokines dysregulation, immunity changes, imbalance of white and brown adipose tissues, and gut microbial dysbiosis in mediating the pathogenic association between visceral adipose tissues and comorbidities. In this review, we explore the epidemiology of excess body weight and the up-to-date mechanism of how excess body weight and obesity lead to chronic complications. We also examine the utilization of visceral fat measurement as an accurate clinical parameter for risk assessment in healthy individuals and clinical outcome prediction in obese subjects. In addition, current approaches for the prevention and treatment of excess body weight and its related metabolic comorbidities are further discussed. DATA AVAILABILITY: No data was used for the research described in the article.

Trust the gut: outcomes of gut microbiota transplant in metabolic and cognitive disorders

Type 2 diabetes mellitus (T2DM) is a main public health concern, with increasing prevalence and growingly premature onset in children, in spite of emerging and successful therapeutic options. T2DM promotes brain aging, and younger age at onset is associated with a higher risk of subsequent dementia. Preventive strategies should address predisposing conditions, like obesity and metabolic syndrome, and be started from very early and even prenatal life. Gut microbiota is an emerging target in obesity, diabetes and neurocognitive diseases, which could be safely modulated since pregnancy and infancy. Many correlative studies have supported its involvement in disease pathophysiology. Faecal material transplantation (FMT) studies have been conducted in clinical and preclinical settings to deliver cause-effect proof and mechanistic insights. This review provides a comprehensive overview of studies in which FMT was used to cure or cause obesity, metabolic syndrome, T2DM, cognitive decline and Alzheimer's disease, including the evidence available in early life. Findings were analysed to dissect consolidated from controversial results, highlighting gaps and possible future directions.

Human gut microbiota after bariatric surgery alters intestinal morphology and glucose absorption in mice independently of obesity

OBJECTIVE

Bariatric surgery is an effective treatment for type 2 diabetes (T2D) that changes gut microbial composition. We determined whether the gut microbiota in humans after restrictive or malabsorptive bariatric surgery was sufficient to lower blood glucose.

DESIGN

Women with obesity and T2D had biliopancreatic diversion with duodenal switch (BPD-DS) or laparoscopic sleeve gastrectomy (LSG). Faecal samples from the same patient before and after each surgery were used to colonise rodents, and determinants of blood glucose control were assessed.

RESULTS

Glucose tolerance was improved in germ-free mice orally colonised for 7 weeks with human microbiota after either BPD-DS or LSG, whereas food intake, fat mass, insulin resistance, secretion and clearance were unchanged. Mice colonised with microbiota post-BPD-DS had lower villus height/width and crypt depth in the distal jejunum and lower intestinal glucose absorption. Inhibition of sodium-glucose cotransporter (Sglt)1 abrogated microbiota-transmissible improvements in blood glucose control in mice. In specific pathogen-free (SPF) rats, intrajejunal colonisation for 4 weeks with microbiota post-BPD-DS was sufficient to improve blood glucose control, which was negated after intrajejunal Sglt-1 inhibition. Higher Parabacteroides and lower Blautia coincided with improvements in blood glucose control after colonisation with human bacteria post-BPD-DS and LSG.

CONCLUSION

Exposure of rodents to human gut microbiota after restrictive or malabsorptive bariatric surgery improves glycaemic control. The gut microbiota after bariatric surgery is a standalone factor that alters upper gut intestinal morphology and lowers Sglt1-mediated intestinal glucose absorption, which improves blood glucose control independently from changes in obesity, insulin or insulin resistance.

Exploration of fMRI brain responses to oral sucrose after Roux-en-Y gastric bypass in obese yucatan minipigs in relationship with microbiota and metabolomics profiles

BACKGROUND & AIMS

In most cases, Roux-en-Y gastric bypass (RYGBP) is an efficient intervention to lose weight, change eating behavior and improve metabolic outcomes in obese patients. We hypothesized that weight loss induced by RYGBP in obese Yucatan minipigs would induce specific modifications of the gut-brain axis and neurocognitive responses to oral sucrose stimulation in relationship with food intake control.

METHODS

An integrative study was performed after SHAM (n = 8) or RYGBP (n = 8) surgery to disentangle the physiological, metabolic and neurocognitive mechanisms of RYGBP. BOLD fMRI responses to sucrose stimulations at different concentrations, brain mRNA expression, cecal microbiota, and plasma metabolomics were explored 4 months after surgery and integrated with WGCNA analysis.

RESULTS

We showed that weight loss induced by RYGBP or SHAM modulated differently the frontostriatal responses to oral sucrose stimulation, suggesting a different hedonic treatment and inhibitory control related to palatable food after RYGBP. The expression of brain genes involved in the serotoninergic and cannabinoid systems were impacted by RYGBP. Cecal microbiota was deeply modified and many metabolite features were differentially increased in RYGBP. Data integration with WGCNA identified interactions between key drivers of OTUs and metabolites features linked to RYGBP.

CONCLUSION

This longitudinal study in the obese minipig model illustrates with a systemic and integrative analysis the mid-term consequences of RYGBP on brain mRNA expression, cecal microbiota and plasma metabolites. We confirmed the impact of RYGBP on functional brain responses related to food reward, hedonic evaluation and inhibitory control, which are key factors for the success of anti-obesity therapy and weight loss maintenance.

Cascading effects of Pb on the environmental and symbiotic microbiota and tadpoles' physiology based on field data and laboratory validation

Heavy metal pollution poses a serious threat to ecosystems. Currently, there is a lack of field data that would enable us to gain a systematic understanding of the influences of heavy metals on aquatic ecosystems, especially the interactions between environments and animals. We studied the relationships between the variations in heavy metal concentrations (10 species including Pb in sediments and surface water), the community structure of environmental and symbiotic microbiota, and the gut traits of Bufo gargarizans tadpoles across 16 sampling sites on the Chengdu Plain through rigorous statistical analysis and laboratory validation. The results show that heavy metal concentrations, especially the Pb concentration of the sediment, are linked to the variations in sediment and tadpoles' gut microbiomes but not to water microbiota. For the sediment microbiota, Pb causes a trade-off between the proportions of Burkholderiales and Verrucomicrobiae and affects the methane, sulfide, and nitrate metabolisms. For tadpoles, a high sediment Pb content leads to a low abundance of gut aerobic bacteria and a large relative gut weight under both field and laboratory conditions. In addition, Pb promotes the growth of B. gargarizans tadpoles under laboratory conditions. These effects seem to be beneficial to tadpoles. However, a high Pb content leads to a low abundance of probiotic bacteria (e.g., Verrucomicrobiae, Eubacteriaceae, and Cetobacterium) and a high abundance of pathogenic bacteria in the gut and environment, suggesting potential health risks posed by Pb. Interestingly, there is a causal relationship between Pb-induced variations in sediment and symbiotic microbiotas, and the latter is further linked to the variation in relative gut weight of tadpoles. This suggests a cascading effect of Pb on the ecosystem. In conclusion, our results indicate that among the heavy metals, the Pb in sediment is a critical factor affecting the aquatic ecosystem through an environment-gut-physiology pathway mediated by microbiota.

The implication of gut microbiota in recovery from gastrointestinal surgery

Recovery from gastrointestinal (GI) surgery is often interrupted by the unpredictable occurrence of postoperative complications, including infections, anastomotic leak, GI dysmotility, malabsorption, cancer development, and cancer recurrence, in which the implication of gut microbiota is beginning to emerge. Gut microbiota can be imbalanced before surgery due to the underlying disease and its treatment. The immediate preparations for GI surgery, including fasting, mechanical bowel cleaning, and antibiotic intervention, disrupt gut microbiota. Surgical removal of GI segments also perturbs gut microbiota due to GI tract reconstruction and epithelial barrier destruction. In return, the altered gut microbiota contributes to the occurrence of postoperative complications. Therefore, understanding how to balance the gut microbiota during the perioperative period is important for surgeons. We aim to overview the current knowledge to investigate the role of gut microbiota in recovery from GI surgery, focusing on the crosstalk between gut microbiota and host in the pathogenesis of postoperative complications. A comprehensive understanding of the postoperative response of the GI tract to the altered gut microbiota provides valuable cues for surgeons to preserve the beneficial functions and suppress the adverse effects of gut microbiota, which will help to enhance recovery from GI surgery.

Black Rice Anthocyanidins Regulates Gut Microbiota and Alleviates Related Symptoms through PI3K/AKT Pathway in Type 2 Diabetic Rats

Black rice anthocyanins (BRAs) have extremely high nutritional value and health care effects. This study investigated the intervention effect of BRAs on type 2 diabetes mellitus (T2DM) and the regulation effect on intestinal microbiota imbalance in T2DM rats. This study established successfully a T2DM model in a high-fat and high-glucose diet combined with streptozotocin (STZ). BRAs intervention reduced significantly the fasting blood glucose level of T2DM rats, improved the glucose tolerance of rats, reduced the blood lipid level and inflammation state, and repaired liver, oxidative stress, and other injuries. In addition, BRAs’s intervention enhanced the expression of phosphoinositol 3-kinase (PI3K)/protein kinase B (AKT), activated the expression of adenosine 5’-monophosphate-activated protein kinase(AMPK), and the downstream acetyl-CoA carboxylase (ACC) and carnitine palmitoyl transferase (CPT1) in the liver. 16S rRNA sequencing showed that BRAs significantly decreased the abundances of Bifidobacterium and Clostridiaceae_Clostridium, and promoted the abundances of Akkermansia and Lactobacillus. Accelerate the recovery of gut microbiota diversity. BRAs play an antidiabetic role by regulating the PI3K/AKT signaling pathway and intestinal microbiota in T2MD rats.

Lipidomic analysis of brain and hippocampus from mice fed with high-fat diet and treated with fecal microbiota transplantation

BACKGROUND

Dietary fat intake affects brain composition and function. Different types of dietary fatty acids alter species and abundance of brain lipids in mice. The aim of this study is to explore whether the changes are effective through gut microbiota.

METHODS

In our study, 8-week-old male C57BL/6 mice were randomly divided into 7 groups and fed with high-fat diet (HFD) with different fatty acid compositions, control (CON) group, long-chain saturated fatty acid (LCSFA) group, medium-chain saturated fatty acid (MCSFA) group, n-3 polyunsaturated fatty acid (n-3 PUFA) group, n-6 polyunsaturated fatty acid (n-6 PUFA) group, monounsaturated fatty acid (MUFA) group and trans fatty acid (TFA) group. Then, the fecal microbiota transplant (FMT) was performed in other pseudo germ-free mice after antibiotic treatment. The experimental groups were orally perfused with gut microbiota that induced by HFD with different types of dietary fatty acids. The mice were fed with regular fodder before and after FMT. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to analysis the composition of fatty acids in the brain of HFD-fed mice and hippocampus of mice treated with FMT which was collected from HFD-fed mice.

RESULTS

The content of acyl-carnitines (AcCa) increased and lysophosphatidylgylcerol (LPG) decreased in all kinds of HFD groups. phosphatidic acids (PA), phosphatidylethanolamine (PE) and sphingomyelin (SM) contents were significantly increased in the n-6 PUFA-fed HFD group. The HFD elevated the saturation of brain fatty acyl (FA). Lysophosphatidylcholine (LPC), lysodi-methylphosphatidylethanolamine (LdMePE), monolysocardiolipin (MLCL), dihexosylceramides (Hex2Cer), and wax ester (WE) significantly increased after LCSFA-fed FMT. MLCL reduced and cardiolipin (CL) raised significantly after n-3 PUFA-fed FMT.

CONCLUSIONS

The study revealed, HFD and FMT in mice had certain effects on the content and composition of fatty acids in the brain, especially on glycerol phospholipid (GP). The change of AcCa content in FA was a good indicator of dietary fatty acid intake. By altering the fecal microbiota, dietary fatty acids might affect brain lipids.

Bacteria with potential: Improving outcomes through probiotic use following Roux-en-Y gastric bypass

Obesity impairs the gastrointestinal microbiome (GM) and may promote micronutrient deficiencies. Bariatric surgery (BS), the most efficacious treatment for severe obesity, produces sustained weight loss and improvements in obesity-related comorbidities, but might not fully restore microbial balance. Moreover, BS may result in deleterious consequences that affect weight loss and further intensify post-operative micronutrient deficiencies. To date, the use of probiotics appears to be associated with greater weight loss in bariatric patients, improved vitamin synthesis and availability, and decreased instances of small intestinal bacterial overgrowth. Thus, manipulation of the GM through probiotics represents a promising therapeutic approach in bariatric patients. This review aims to highlight the benefits of using probiotics in bariatric surgical patients by addressing the impact of probiotics on the GM, how BS impacts the microbial environment, associations between gastrointestinal dysbiosis and negative health outcomes, how BS contributes to dysbiosis, and how probiotics may prove efficacious in treating patients who undergo Roux-en-Y gastric bypass (RYGB). Based on currently available data, the role of microbial manipulation post-RYGB through probiotics has shown great potential, but a further clinical investigation is warranted to better understand their efficacy.

Efficacy and safety of single-anastomosis duodenal-ileal bypass with sleeve gastrectomy for the treatment of Chinese T2D patients with obesity

BACKGROUND

Bariatric surgery is the most effective treatment for obese T2D. As one of the most effective bariatric surgeries, SADI-S was recently introduced in China, and there is limited evidence of its efficacy and safety in the treatment of obese T2D. The aim of this study is to investigate the safety and efficacy of SADI-S in the treatment of obese T2D in China.

METHODS

The clinical data of 32 obese T2D patients who underwent SADI-S was included in this study. Changes in weight-related indicators, diabetes-related indicators, and patient nutritional outcomes were analyzed.

RESULTS

SADI-S was conducted successfully in all of the 32 cases without conversion to laparotomy or death. The incidence of surgical complications was 15.6% (5/32). The major complication rate was 6.3% (2/32). At 1 year after surgery, the BMI (kg/m²) significantly decreased from 40.8 ± 7.4 to 23.9 ± 2.9 (P < 0.05) and the mean HbA1c significantly decreased from 8.5% (6.4-11.5) to 5.0% (3.8-5.6) (P < 0.05). At 2 years after surgery, the BMI (kg/m²) significantly decreased to 24.9 ± 2.4 (P < 0.05) and the mean HbA1c significantly decreased to (4.8 ± 0.4)% (P < 0.05). The %TWL was (40.4 ± 6.5)% and (42.9 ± 4.9)% at 1 year and 2 years, respectively. The complete remission rates for T2D were both 100% at 1 year and 2 years. Triglyceride levels were significantly improved compared with preoperative, from (3.2 ± 3.0) mmol/L to (1.0 ± 0.3) mmol/L (P < 0.05), but there was no significant difference in other nutritional outcomes.

CONCLUSION

The SADI-S has excellent curative effect in the treatment of Chinese obese T2D, but the operation is challenging and the complication rate is high. Its long-term efficacy and safety require further study.

Regulation of body weight: Lessons learned from bariatric surgery

BACKGROUND

Bariatric or weight loss surgery is currently the most effective treatment for obesity and metabolic disease. Unlike dieting and pharmacology, its beneficial effects are sustained over decades in most patients, and mortality is among the lowest for major surgery. Because there are not nearly enough surgeons to implement bariatric surgery on a global scale, intensive research efforts have begun to identify its mechanisms of action on a molecular level in order to replace surgery with targeted behavioral or pharmacological treatments. To date, however, there is no consensus as to the critical mechanisms involved.

SCOPE OF REVIEW

The purpose of this non-systematic review is to evaluate the existing evidence for specific molecular and inter-organ signaling pathways that play major roles in bariatric surgery-induced weight loss and metabolic benefits, with a focus on Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), in both humans and rodents.

MAJOR CONCLUSIONS

Gut-brain communication and its brain targets of food intake control and energy balance regulation are complex and redundant. Although the relatively young science of bariatric surgery has generated a number of hypotheses, no clear and unique mechanism has yet emerged. It seems increasingly likely that the broad physiological and behavioral effects produced by bariatric surgery do not involve a single mechanism, but rather multiple signaling pathways. Besides a need to improve and better validate surgeries in animals, advanced techniques, including inducible, tissue-specific knockout models, and the use of humanized physiological traits will be necessary. State-of-the-art genetically-guided neural identification techniques should be used to more selectively manipulate function-specific pathways.

Microbiome epidemiology and association studies in human health

Studies of the human microbiome share both technical and conceptual similarities with genome-wide association studies and genetic epidemiology. However, the microbiome has many features that differ from genomes, such as its temporal and spatial variability, highly distinct genetic architecture and person-to-person variation. Moreover, there are various potential mechanisms by which distinct aspects of the human microbiome can relate to health outcomes. Recent advances, including next-generation sequencing and the proliferation of multi-omic data types, have enabled the exploration of the mechanisms that connect microbial communities to human health. Here, we review the ways in which features of the microbiome at various body sites can influence health outcomes, and we describe emerging opportunities and future directions for advanced microbiome epidemiology.

Adult focal β-cell nesidioblastosis: A case report

BACKGROUND

Nesidioblastosis usually refers to a series of clinical manifestations caused by the proliferation of β-cells in pancreatic islets, and these clinical manifestations are hyperinsulinemia and persistent hypoglycemia. According to the size of the lesion, nesidioblastosis is divided into focal nesidioblastosis, diffuse nesidioblastosis and atypical nesidioblastosis, and its pathogenesis is still unclear. Nesidioblastosis is mainly seen in infants and rarely reported in adults, especially focal nesidioblastosis, which is difficult to distinguish from insulinoma.

CASE SUMMARY

We report a case of adult focal β-cell nesidioblastosis in which the preoperative diagnosis was insulinoma. The patient was a 48-year-old male who suffered from repeated morning and fasting palpitations, sweating, and severe disturbance of consciousness for 5 years. His blood glucose was found to be as low as 1.79 mmol/L during an attack. However, abdominal computed tomography showed no abnormalities. Magnetic resonance imaging and endoscopic ultrasonography demonstrated a nodular mass in the head of the pancreas, combined with hyperinsulinemia and high serum C-peptide. The patient was diagnosed with insulinoma and underwent Beger surgery; however, the postoperative pathological results showed nesidioblastosis.

CONCLUSION

Although surgical resection is the preferred option for nesidioblastosis, some cases can be treated non-surgically. In order to increase clinicians' understanding of nesidioblastosis, it is necessary to review the pathogenesis, diagnosis and treatment of this disease.

Celastrol directly binds with VAMP7 and RAB7 to inhibit autophagy and induce apoptosis in preadipocytes

Obesity is one of the most prevalent chronic metabolic diseases, and induction of apoptosis in preadipocytes and adipocytes is a potential strategy to treat obesity. Celastrol represents one of the most robust anti-obesity phytochemicals so far, yet its direct binding target remains elusive. Here, we determined that celastrol could induce apoptosis in preadipocytes via mitochondrial mediated pathway. Further study clarified that celastrol inhibited the fusion of autophagosome and lysosome to prohibit autophagy, leading to cell apoptosis. By conducting virtual screening and genetic manipulation, we verified that overexpression of VAMP7 and RAB7 could block the effects of celastrol on inhibiting autophagy and inducing apoptosis. The Surface Plasmon Resonance study confirmed the direct binding of celastrol with VAMP7 and RAB7. The functional study illustrated the inhibition of RAB7 GTPase activity after celastrol treatment. Moreover, celastrol induced comparable apoptosis in murine epididymal adipose tissue, human preadipocytes and adipocytes, but not in human hepatocytes. An inhibitory effect on differentiation of human primary visceral preadipocytes was also observed. In conclusion, celastrol exhibited inhibitory effect of autophagy via direct binding with VAMP7 and RAB7, leading to an increase in preadipocytes apoptosis. These results advance our understanding in the potential application of celastrol in treating obesity.

Gut microbiota modulation in patients with non-alcoholic fatty liver disease: Effects of current treatments and future strategies

Non-alcoholic fatty liver disease (NAFLD) is frequently associated with metabolic disorders, being highly prevalent in obese and diabetic patients. Many concomitant factors that promote systemic and liver inflammation are involved in NAFLD pathogenesis, with a growing body of evidence highlighting the key role of the gut microbiota. Indeed, the gut-liver axis has a strong impact in the promotion of NAFLD and in the progression of the wide spectrum of its manifestations, claiming efforts to find effective strategies for gut microbiota modulation. Diet is among the most powerful tools; Western diet negatively affects intestinal permeability and the gut microbiota composition and function, selecting pathobionts, whereas Mediterranean diet fosters health-promoting bacteria, with a favorable impact on lipid and glucose metabolism and liver inflammation. Antibiotics and probiotics have been used to improve NAFLD features, with mixed results. More interestingly, medications used to treat NAFLD-associated comorbidities may also modulate the gut microbiota. Drugs for the treatment of type 2 diabetes mellitus (T2DM), such as metformin, glucagon-like peptide-1 (GLP-1) agonists, and sodium-glucose cotransporter (SGLT) inhibitors, are not only effective in the regulation of glucose homeostasis, but also in the reduction of liver fat content and inflammation, and they are associated with a shift in the gut microbiota composition towards a healthy phenotype. Even bariatric surgery significantly changes the gut microbiota, mostly due to the modification of the gastrointestinal anatomy, with a parallel improvement in histological features of NAFLD. Other options with promising effects in reprogramming the gut-liver axis, such as fecal microbial transplantation (FMT) and next-generation probiotics deserve further investigation for future inclusion in the therapeutic armamentarium of NAFLD.

Microbiota in the Natural History of Pancreatic Cancer: From Predisposition to Therapy

Early microbiome insights came from gut microbes and their role among intestinal and extraintestinal disease. The latest evidence suggests that the microbiota is a true organ, capable of several interactions throughout the digestive system, attracting specific interest in the biliopancreatic district. Despite advances in diagnostics over the last few decades and improvements in the management of this disease, pancreatic cancer is still a common cause of cancer death. Microbiota can influence the development of precancerous disease predisposing to pancreatic cancer (PC). At the same time, neoplastic tissue shows specific characteristics in terms of diversity and phenotype, determining the short- and long-term prognosis. Considering the above information, a role for microbiota has also been hypothesized in the different phases of the PC approach, providing future revolutionary therapeutic insights. Microbiota-modulating therapies could open new issues in the therapeutic landscape. The aim of this narrative review is to assess the most updated evidence on microbiome in all the steps regarding pancreatic adenocarcinoma, from early development to response to antineoplastic therapy and long-term prognosis.

The Role of the Gut Microbiome in Pediatric Obesity and Bariatric Surgery

Obesity affects 42.4% of adults and 19.3% of children in the United States. Childhood obesity drives many comorbidities including hypertension, fatty liver disease, and type 2 diabetes mellitus. Prior research suggests that aberrant compositional development of the gut microbiome, with low-grade inflammation, precedes being overweight. Therefore, childhood may provide opportunities for interventions that shape the microbiome to mitigate obesity-related diseases. Children with obesity have gut microbiota compositional and functional differences, including increased proinflammatory bacterial taxa, compared to lean controls. Restoration of the gut microbiota to a healthy state may ameliorate conditions associated with obesity and help maintain a healthy weight. Pediatric bariatric (weight-loss) surgery is an effective treatment for childhood obesity; however, there is limited research into the role of the gut microbiome after weight-loss surgery in children. This review will discuss the magnitude of childhood obesity, the importance of the developing microbiome in establishing metabolic pathways, interventions such as bariatric surgery that may modulate the gut microbiome, and future directions for the potential development of microbiome-based therapeutics to treat obesity.

Immunomodulation by foods and microbes: Unravelling the molecular tango

Metabolic health and immune function are intimately connected via diet and the microbiota. Nearly 90% of all immune cells in the body are associated with the gastrointestinal tract and these immune cells are continuously exposed to a wide range of microbes and microbial-derived compounds, with important systemic ramifications. Microbial dysbiosis has consistently been observed in patients with atopic dermatitis, food allergy and asthma and the molecular mechanisms linking changes in microbial populations with disease risk and disease endotypes are being intensively investigated. The discovery of novel bacterial metabolites that impact immune function is at the forefront of host-microbe research. Co-evolution of microbial communities within their hosts has resulted in intertwined metabolic pathways that affect physiological and pathological processes. However, recent dietary and lifestyle changes are thought to negatively influence interactions between microbes and their host. This review provides an overview of some of the critical metabolite-receptor interactions that have been recently described, which may underpin the immunomodulatory effects of the microbiota, and are of relevance for allergy, asthma and infectious diseases.

The gut microbiota as a therapeutic target for obesity: a scoping review

There is mounting evidence that microbiome composition is intimately and dynamically connected with host energy balance and metabolism. The gut microbiome is emerging as a novel target for counteracting the chronically positive energy balance in obesity, a disease of pandemic scale which contributes to >70 % of premature deaths. This scoping review explores the potential for therapeutic modulation of gut microbiota as a means of prevention and/or treatment of obesity and obesity-associated metabolic disorders. The evidence base for interventional approaches which have been shown to affect the composition and function of the intestinal microbiome is summarised, including dietary strategies, oral probiotic treatment, faecal microbiota transplantation and bariatric surgery. Evidence in this field is still largely derived from preclinical rodent models, but interventional studies in obese populations have demonstrated metabolic improvements effected by microbiome-modulating treatments such as faecal microbiota transplantation, as well as drawing attention to the unappreciated role of microbiome modulation in well-established anti-obesity interventions, such as dietary change or bariatric surgery. The complex relationship between microbiome composition and host metabolism will take time to unravel, but microbiome modulation is likely to provide a novel strategy in the limited armamentarium of effective treatments for obesity.

Intake of slow-digesting carbohydrates is related to changes in the microbiome and its functional pathways in growing rats with obesity induced by diet

INTRODUCTION

The main cause of insulin resistance in childhood is obesity, which contributes to future comorbidities as in adults. Although high-calorie diets and lack of exercise contribute to metabolic disease development, food quality rather than the quantity of macronutrients is more important than food density. The purpose of the present study was to examine the effects of changing the quality of carbohydrates from rapidly to slowly digestible carbohydrates on the composition of the gut microbiota and the profiles of the functional pathways in growing rats with obesity due to a high-fat diet (HFD).

METHODS

During the course of 4 weeks, rats growing on an HFD-containing carbohydrates with different digestive rates were fed either HFD-containing carbohydrates with a rapid digestion rate (OBE group) or HFD-containing carbohydrates with a slow digestion rate (OBE-ISR group). A non-obese group (NOB) was included as a reference, and rats were fed on a rodent standard diet (AIN93G). An analysis of gut microbiota was conducted using 16S rRNA-based metagenomics; a linear mixed-effects model (LMM) was used to determine changes in abundance between baseline and 4 weeks of treatment, and functional pathways were identified. Gut microbiota composition at bacterial diversity and relative abundance, at phylum and genus levels, and functional profiles were analyzed by integrating the Integrated Microbial Genomes (IMG) database.

RESULTS

The groups showed comparable gut microbiota at baseline. At the end of the treatment, animals from the ISR group exhibited differences at the phylum levels by decreasing the diversity of Fisher's index and Firmicutes (newly named as Bacillota), and increasing the Pielou's evenness and Bacteroidetes (newly named as Bacteroidota); at the genus level by increasing Alistipes, Bifidobacterium, Bacteroides, Butyricimonas, Lachnoclostridium, Flavonifractor, Ruminiclostridium 5, and Faecalibaculum and decreasing Muribaculum, Blautia, and Ruminiclostridium 9. Remarkably, relative abundances of genera Tyzzerella and Angelakisella were higher in the OBE group compared to NOB and OBE-ISR groups. In addition, some microbiota carbohydrate metabolism pathways such as glycolysis, glucuronic acid degradation, pentose phosphate pathway, methanogenesis, and fatty acid biosynthesis exhibited increased activity in the OBE-ISR group after the treatment. Higher levels of acetate and propionate were found in the feces of the ISR group compared with the NOB and OBE groups.

CONCLUSION

The results of this study demonstrate that replacing rapidly digestible carbohydrates with slowly digestible carbohydrates within an HFD improve the composition of the gut microbiota. Consequently, metabolic disturbances associated with obesity may be prevented.

The gut peptide Reg3g links the small intestine microbiome to the regulation of energy balance, glucose levels, and gut function

Changing composition of the gut microbiome is an important component of the gut adaptation to various environments, which have been implicated in various metabolic diseases including obesity and type 2 diabetes, but the mechanisms by which the microbiota influence host physiology remain contentious. Here we find that both diets high in the fermentable fiber inulin and vertical sleeve gastrectomy increase intestinal expression and circulating levels of the anti-microbial peptide Reg3g. Moreover, a number of beneficial effects of these manipulations on gut function, energy balance, and glucose regulation are absent in Reg3g knockout mice. Peripheral administration of various preparations of Reg3g improves glucose tolerance, and this effect is dependent on the putative receptor Extl3 in the pancreas. These data suggest Reg3g acts both within the lumen and as a gut hormone to link the intestinal microbiome to various aspects of host physiology that may be leveraged for novel treatment strategies.

Multi-omic phenotyping reveals host-microbe responses to bariatric surgery, glycaemic control and obesity

Background

Resolution of type 2 diabetes (T2D) is common following bariatric surgery, particularly Roux-en-Y gastric bypass. However, the underlying mechanisms have not been fully elucidated.

Methods

To address this we compare the integrated serum, urine and faecal metabolic profiles of participants with obesity ± T2D (n = 80, T2D = 42) with participants who underwent Roux-en-Y gastric bypass or sleeve gastrectomy (pre and 3-months post-surgery; n = 27), taking diet into account. We co-model these data with shotgun metagenomic profiles of the gut microbiota to provide a comprehensive atlas of host-gut microbe responses to bariatric surgery, weight-loss and glycaemic control at the systems level.

Results

Here we show that bariatric surgery reverses several disrupted pathways characteristic of T2D. The differential metabolite set representative of bariatric surgery overlaps with both diabetes (19.3% commonality) and body mass index (18.6% commonality). However, the percentage overlap between diabetes and body mass index is minimal (4.0% commonality), consistent with weight-independent mechanisms of T2D resolution. The gut microbiota is more strongly correlated to body mass index than T2D, although we identify some pathways such as amino acid metabolism that correlate with changes to the gut microbiota and which influence glycaemic control.

Conclusion

We identify multi-omic signatures associated with responses to surgery, body mass index, and glycaemic control. Improved understanding of gut microbiota - host co-metabolism may lead to novel therapies for weight-loss or diabetes. However, further experiments are required to provide mechanistic insight into the role of the gut microbiota in host metabolism and establish proof of causality.

Gut microbiome and microbial metabolites in NAFLD and after bariatric surgery: Correlation and causality

Non-alcoholic fatty liver disease (NAFLD) is currently related to a heavy socioeconomic burden and increased incidence. Since obesity is the most prevalent risk factor for NAFLD, weight loss is an effective therapeutic solution. Bariatric surgery (BS), which can achieve long-term weight loss, improves the overall health of patients with NAFLD. The two most common surgeries are the Roux-en-Y gastric bypass and sleeve gastrectomy. The gut-liver axis is the complex network of cross-talking between the gut, its microbiome, and the liver. The gut microbiome, involved in the homeostasis of the gut-liver axis, is believed to play a significant role in the pathogenesis of NAFLD and the metabolic improvement after BS. Alterations in the gut microbiome in NAFLD have been confirmed compared to that in healthy individuals. The mechanisms linking the gut microbiome to NAFLD have been proposed, including increased intestinal permeability, higher energy intake, and other pathophysiological alterations. Interestingly, several correlation studies suggested that the gut microbial signatures after BS become more similar to those of lean, healthy controls than that of patients with NAFLD. The resolution of NAFLD after BS is related to changes in the gut microbiome and its metabolites. However, confirming a causal link remains challenging. This review summarizes characteristics of the gut microbiome in patients with NAFLD before and after BS and accumulates existing evidence about the underlying mechanisms of the gut microbiome.

Modulatory role of gut microbiota in cholesterol and glucose metabolism: Potential implications for atherosclerotic cardiovascular disease Atherosclerosis

Accumulating evidence suggests an important role of gut microbiota in physiological processes of host metabolism as well as cardiometabolic disease. Recent advances in metagenomic and metabolomic research have led to discoveries of novel pathways in which intestinal microbial metabolism of dietary nutrients is linked to metabolic profiles and cardiovascular disease risk. A number of metaorganismal circuits have been identified by microbiota transplantation studies and experimental models using germ-free rodents. Many of these pathways involve gut microbiota-related bioactive metabolites that impact host metabolism, in particular lipid and glucose homeostasis, partly via specific host receptors. In this review, we summarize the current knowledge of how the gut microbiome can impact cardiometabolic phenotypes and provide an overview of recent advances of gut microbiome research. Finally, the potential of modulating intestinal microbiota composition and/or targeting microbiota-related pathways for novel preventive and therapeutic strategies in cardiometabolic and cardiovascular diseases will be discussed.

Morchella esculenta polysaccharide attenuate obesity, inflammation and modulate gut microbiota

Edible mushrooms have now been suggested as promising sources of biological functional ingredients and are the subject of the most recent nutrition research and novel functional foods. Polysaccharides from mushrooms exhibit impressive biological effects, notably against obesity. Obesity is a chronic metabolic disorder characterized by chronic inflammation, gut dysbiosis, and hyperpermeability of the colon. Here, we prove that mushrooms Morchella esculenta polysaccharide (MEP) effects on HFD-induced obesity, colonic inflammation, and gut microbiota dysbiosis. Our findings demonstrate MEP supplementation attenuates obesity parameters and reduces inflammation in the colon via regulation of Toll-like receptor 4 (TLR4), nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and inactivation of nuclear factor kappa B (NF-κB). Furthermore, MEP administration restores gut microbiota dysregulation by ameliorating Firmicutes to Bacteroidetes proportion as well as enhancing beneficial bacteria, like Lactobacillus, and inhibiting pathogenic bacteria like Enterococcus. MEP improves gut integrity by increasing tight junction proteins (TJs) and reducing endotoxin levels by controlling Lipopolysaccharide (LPS) in HFD-induced obese mice. These results demonstrated the therapeutic efficacy of MEP in attenuating HFD-induced obesity via regulating inflammatory cascades, ameliorating the gut microbiome, and modulating gut integrity.

The role of obesity and bariatric surgery-induced weight loss in breast cancer

Obesity is a complex metabolic condition considered a worldwide public health crisis, and a deeper mechanistic understanding of obesity-associated diseases is urgently needed. Obesity comorbidities include many associated cancers and are estimated to account for 20% of female cancer deaths in the USA. Breast cancer, in particular, is associated with obesity and is the focus of this review. The exact causal links between obesity and breast cancer remain unclear. Still, interactions have emerged between body mass index, tumor molecular subtype, genetic background, and environmental factors that strongly suggest obesity influences the risk and progression of certain breast cancers. Supportive preclinical research uses various diet-induced obesity models to demonstrate that weight loss, via dietary interventions or changes in energy expenditure, reduces the onset or progression of breast cancers. Ongoing and future studies are now aimed at elucidating the underpinning mechanisms behind weight-loss-driven observations to improve therapy and outcomes in patients with breast cancer and reduce risk. This review aims to summarize the rapidly emerging literature on obesity and weight loss strategies with a focused discussion of bariatric surgery in both clinical and preclinical studies detailing the complex interactions between metabolism, immune response, and immunotherapy in the setting of obesity and breast cancer.

Fecal microbiota transplantation for diseases: Therapeutic potential, methodology, risk management in clinical practice

BACKGROUND

More than 95 % of human diseases may be related to the disturbance of gut microbes. As a treatment method that extensively regulates the gut microbes, fecal microbiota transplantation (FMT) has proven to be an effective therapy for some diseases, becoming a topic of interest among clinicians, patients and scientists.

AIM

To review the latest clinical research results of FMT in the treatment of various diseases and the methodology and risk management in clinical application.

METHODS

Search PubMed and Web of Science for reliable research results of clinical treatment of FMT within 5-10 years, as well as application guidelines and risk management policies in different regions.

RESULTS

As a measure of allogeneic/autologous microbiota transplantation, FMT has been used to treat a variety of diseases. By reviewing the clinical studies of FMT in gastrointestinal diseases, metabolic diseases, neurological diseases and malignant tumors, the various mechanisms in the treatment of diseases are summarized. Such as regulation of receptor microbiota composition, specific metabolites, phage function and immune response. In addition, potential risk factors, donor stool screening indicators, recipient self-specificity and possible prognostic marker molecules in the course of FMT treatment were generalized.

CONCLUSIONS

The potential regulatory mechanisms, risk factors and targets of FMT in gastrointestinal diseases, metabolic diseases, malignancies and neurological diseases were reviewed and proposed. It provides a theoretical basis for the establishment of a standardized treatment system for FMT and a breakthrough in treatment technology.

Bile acid metabolism and signaling, the microbiota, and metabolic disease

The diversity, composition, and function of the bacterial community inhabiting the human gastrointestinal tract contributes to host health through its role in producing energy or signaling molecules that regulate metabolic and immunologic functions. Bile acids are potent metabolic and immune signaling molecules synthesized from cholesterol in the liver and then transported to the intestine where they can undergo metabolism by gut bacteria. The combination of host- and microbiota-derived enzymatic activities contribute to the composition of the bile acid pool and thus there can be great diversity in bile acid composition that depends in part on the differences in the gut bacteria species. Bile acids can profoundly impact host metabolic and immunological functions by activating different bile acid receptors to regulate signaling pathways that control a broad range of complex symbiotic metabolic networks, including glucose, lipid, steroid and xenobiotic metabolism, and modulation of energy homeostasis. Disruption of bile acid signaling due to perturbation of the gut microbiota or dysregulation of the gut microbiota-host interaction is associated with the pathogenesis and progression of metabolic disorders. The metabolic and immunological roles of bile acids in human health have led to novel therapeutic approaches to manipulate the bile acid pool size, composition, and function by targeting one or multiple components of the microbiota-bile acid-bile acid receptor axis.

Association of Gut Microbiota with Atherogenic Dyslipidemia, and Its Impact on Serum Lipid Levels after Bariatric Surgery

Gut microbiota has been suggested to modulate circulating lipids. However, the relationship between the gut microbiota and atherogenic dyslipidemia (AD), defined as the presence of both low HDL-C and hypertriglyceridemia, is not fully understood. Moreover, because obesity is among the main causes of secondary AD, it is important to analyze the effect of gut microbiota composition on lipid profiles after a weight loss intervention. We compared the microbial diversity and taxonomic composition in patients with AD (n = 41) and controls (n = 38) and sought correlations of genera abundance with serum lipid levels in 20 patients after weight loss induced by Roux-en-Y gastric bypass (RYGB) surgery. Gut microbiota composition was profiled using next-generation sequencing of 16S rRNA. Gut microbiota diversity was significantly lower in atherogenic dyslipidemia. Moreover, relative abundance of two genera with LDA score >3.5 (Megasphaera and LPS-producing Escherichia-Shigella), was significantly higher in AD subjects, while the abundance of four short chain fatty acids (SCFA) producing-genera (Christensenellaceae R-7, Ruminococcaceae UCG-014; Akkermansia and [Eubacterium] eligens group) was significantly higher in controls. Notably, [Eubacterium] eligens group abundance was also significantly associated with higher HDL-C levels in RYGB patients one year after surgery. Although dietary polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratio and PUFA intake were higher in controls than in AD subjects, of the four genera differentiated in cases and controls, only Akkermansia abundance showed a positive and significant correlation with PUFA/SFA ratio. Our results suggest that SCFA-producing bacteria promote a healthy lipid homeostasis, while the presence of LPS-producing bacteria such Escherichia-Shigella may contribute to the development of atherogenic dyslipidemia.

Porphyran From Porphyra haitanensis Alleviates Obesity by Reducing Lipid Accumulation and Modulating gut Microbiota Homeostasis

Porphyran possesses various activities, while the effects of the porphyran from Porphyra haitanensis (PPH) on obesity are rarely reported. In this study, C57BL/6J male mice were fed with HFD combined with PPH gavage (50 mg/kg/d) for 16 weeks, and body weight was measured once a week. After that, serum, adipose, and liver tissues were collected for physiological and biochemical analyses. Our research indicated that PPH treatment alleviated obesity in HFD-fed mice. PPH alleviated fat accumulation in serum, liver, and adipose tissues. In addition, PPH activated the AMPK-HSL/ACC pathway in epididymal adipose tissue to reduce lipid accumulation. Moreover, PPH turned white adipose into brown and activated the PGC 1α-UCP 1-mitochondrial pathway in scapular adipose tissue to generate more heat. Interestingly, PPH regulated colonic microbiota homeostasis in obese mice, including significant elevation of Roseburia and Eubacterium and marked reduction of Helicobacter. Moreover, Spearman’s correlation analysis demonstrated that regulation of gut microbiota can decrease lipid accumulation. In summary, our study illustrated that PPH possesses the potential to be developed as an anti-obesity agent.

Role of gut microbiota in postoperative complications and prognosis of gastrointestinal surgery: A narrative review

Gastrointestinal surgery is often challenging because of unexpected postoperative complications such as pouchitis, malabsorption, anastomotic leak, diarrhea, inflammatory responses, and life-threatening infections. Moreover, the gut microbiota has been shown to be associated with the complications described above. Major intestinal reconstruction, such as Roux-en-Y gastric bypass (RYGB) and ileal pouch-anal anastomosis surgery, could result in altered gut microbiota, which might lead to some of the benefits of these procedures but could also contribute to the development of postsurgical complications. Moreover, postsurgical reestablishment of the gut microbiota population is still poorly understood. Here, we review evidence outlining the role of gut microbiota in complications of gastrointestinal surgery, especially malabsorption, anastomotic leak, pouchitis, and infections. In addition, this review will evaluate the risks and benefits of live biotherapeutics in the complications of gastrointestinal surgery.

Utilizing the Gastrointestinal Microbiota to Modulate Cattle Health through the Microbiome-Gut-Organ Axes

The microorganisms inhabiting the gastrointestinal tract (GIT) of ruminants have a mutualistic relationship with the host that influences the efficiency and health of the ruminants. The GIT microbiota interacts with the host immune system to influence not only the GIT, but other organs in the body as well. The objective of this review is to highlight the importance of the role the gastrointestinal microbiota plays in modulating the health of a host through communication with different organs in the body through the microbiome-gut-organ axes. Among other things, the GIT microbiota produces metabolites for the host and prevents the colonization of pathogens. In order to prevent dysbiosis of the GIT microbiota, gut microbial therapies can be utilized to re-introduce beneficial bacteria and regain homeostasis within the rumen environment and promote gastrointestinal health. Additionally, controlling GIT dysbiosis can aid the immune system in preventing disfunction in other organ systems in the body through the microbiome-gut-brain axis, the microbiome-gut-lung axis, the microbiome-gut-mammary axis, and the microbiome-gut-reproductive axis.

Functional changes of the gastric bypass microbiota reactivate thermogenic adipose tissue and systemic glucose control via intestinal FXR-TGR5 crosstalk in diet-induced obesity

BACKGROUND

Bariatric surgery remains the most effective therapy for adiposity reduction and remission of type 2 diabetes. Although different bariatric procedures associate with pronounced shifts in the gut microbiota, their functional role in the regulation of energetic and metabolic benefits achieved with the surgery are not clear.

METHODS

To evaluate the causal as well as the inherent therapeutic character of the surgery-altered gut microbiome in improved energy and metabolic control in diet-induced obesity, an antibiotic cocktail was used to eliminate the gut microbiota in diet-induced obese rats after gastric bypass surgery, and gastric bypass-shaped gut microbiota was transplanted into obese littermates. Thorough metabolic profiling was combined with omics technologies on samples collected from cecum and plasma to identify adaptions in gut microbiota-host signaling, which control improved energy balance and metabolic profile after surgery.

RESULTS

In this study, we first demonstrate that depletion of the gut microbiota largely reversed the beneficial effects of gastric bypass surgery on negative energy balance and improved glucolipid metabolism. Further, we show that the gastric bypass-shaped gut microbiota reduces adiposity in diet-induced obese recipients by re-activating energy expenditure from metabolic active brown adipose tissue. These beneficial effects were linked to improved glucose homeostasis, lipid control, and improved fatty liver disease. Mechanistically, these effects were triggered by modulation of taurine metabolism by the gastric bypass gut microbiota, fostering an increased abundance of intestinal and circulating taurine-conjugated bile acid species. In turn, these bile acids activated gut-restricted FXR and systemic TGR5 signaling to stimulate adaptive thermogenesis.

CONCLUSION

Our results establish the role of the gut microbiome in the weight loss and metabolic success of gastric bypass surgery. We here identify a signaling cascade that entails altered bile acid receptor signaling resulting from a collective, hitherto undescribed change in the metabolic activity of a cluster of bacteria, thereby readjusting energy imbalance and metabolic disease in the obese host. These findings strengthen the rationale for microbiota-targeted strategies to improve and refine current therapies of obesity and metabolic syndrome. Video Abstract Bariatric Surgery (i.e. RYGB) or the repeated fecal microbiota transfer (FMT) from RYGB donors into DIO (diet-induced obesity) animals induces shifts in the intestinal microbiome, an effect that can be impaired by oral application of antibiotics (ABx). Our current study shows that RYGB-dependent alterations in the intestinal microbiome result in an increase in the luminal and systemic pool of Taurine-conjugated Bile acids (TCBAs) by various cellular mechanisms acting in the intestine and the liver. TCBAs induce signaling via two different receptors, farnesoid X receptor (FXR, specifically in the intestines) and the G-protein-coupled bile acid receptor TGR5 (systemically), finally resulting in metabolic improvement and advanced weight management. BSH, bile salt hydrolase; BAT brown adipose tissue.

Dietary Influences on Gut Microbiota with a Focus on Metabolic Syndrome

There is a clear correlation between gut microbiota, diet, and metabolic outcomes. A diet high in fiber has been shown to decrease inflammation, increase insulin sensitivity, and reduce dyslipidemias whereas a diet high in fat and sugar leads to dyslipidemia, insulin resistance, and low-grade inflammation. There is recent evidence suggesting that the human gut microbiota has a significant role in the development or the resolution of metabolic syndrome (MetS) and associated conditions. Leading a stressful, sedentary lifestyle with limited or no physical activity and consuming an unhealthy diet high in saturated fat, simple carbohydrates, and sodium and low in dietary fiber and in high-quality protein are some of the contributing factors. Unhealthy diets have been shown to induce alterations in the gut microbiota and contribute to the pathogenesis of MetS by altering microbiota composition and disrupting the intestinal barrier, which leads to low-grade systemic inflammation. In contrast, healthy diets can lead to changes in microbiota that increase gut barrier function and increase the production of anti-inflammatory biomarkers. This review aims at providing a more in-depth discussion of diet-induced dysbiosis of the gut microbiota and its effect on MetS. Here, we discuss the possible mechanisms involved in the development of the metabolic biomarkers that define MetS, with an emphasis on the role of sugar and dietary fiber in microbiome-mediated changes in low-grade systemic inflammation and metabolic dysfunction.

Obesity and the Brain

Innate and adaptive immunity are essential for neurodevelopment and central nervous system (CNS) homeostasis; however, the fragile equilibrium between immune and brain cells can be disturbed by any immune dysregulation and cause detrimental effects. Accumulating evidence indicates that, despite the blood-brain barrier (BBB), overactivation of the immune system leads to brain vulnerability that increases the risk of neuropsychiatric disorders, particularly upon subsequent exposure later in life. Disruption of microglial function in later life can be triggered by various environmental and psychological factors, including obesity-driven chronic low-grade inflammation and gut dysbiosis. Increased visceral adiposity has been recognized as an important risk factor for multiple neuropsychiatric conditions. The review aims to present our current understanding of the topic.

Gut Microbes Reveal Pseudomonas Medicates Ingestion Preference via Protein Utilization and Cellular Homeostasis Under Feed Domestication in Freshwater Drum, Aplodinotus grunniens

With strong demand for aquatic products, as well as a rapid decrease in global fishery resources and capture fisheries, domesticating animals to provide more high-quality proteins is meaningful for humans. Freshwater drum (Aplodinotus grunniens) is widely distributed in the wild habitats of North America. However, the research on A. grunniens and the feed domestication with diets composed of artificial compounds remains unclear. In this study, a 4-month feeding domestication experiment was conducted with A. grunniens larvae to evaluate the underlying mechanism and molecular targets responsible for alternations in the ingestion performance. The results indicated that a significant increase in the final body weight was exhibited by the feed domesticated group (DOM, 114.8 g) when compared to the group that did not ingest the feed (WT, 5.3 g) as the latest version we raised From the result, the final body weight exhibited significant increase between unfavorable with the feed (WT, 5.3 g) and feed domesticated group (DOM, 114.8 g). In addition, the enzyme activity of digestive enzymes like amylase, lipase, and trypsin was increased in DOM. Genes related to appetite and perception, such as NPY4R, PYY, and LEPR, were activated in DOM. 16s rRNA gene sequencing analysis revealed that Pseudomonas sp. increased from 58.74% to 89.77% in DOM, which accounts for the dominant upregulated microbial community at the genus level, followed by Plesiomonas. Analogously, Mycobacterium, Methylocystis, and Romboutsia also accounted for the down-regulated microbes in the diversity. Transcriptome and RT-PCR analysis revealed that feed domestication significantly improved protein digestion and absorption, inhibited apoptosis by AGE-RAGE signaling, and activated extracellular matrix remodeling by relaxin signaling. Integrated analysis of the microbiome and host transcriptome revealed that Pseudomonas-mediated ingestion capacity, protein utilization, and cellular homeostasis might be the underlying mechanism under feed domestication. These results indicate Pseudomonas and its key genes relating to food ingestion and digestion could serve as the molecular targets for feed domestication and sustainable development in A. grunniens.

Gut microbiome: Linking together obesity, bariatric surgery and associated clinical outcomes under a single focus

Obesity is increasingly prevalent in the post-industrial era, with increased mortality rates. The gut microbiota has a central role in immunological, nutritional and metabolism mediated functions, and due to its multiplexity, it is considered an independent organ. Modern high-throughput sequencing techniques have allowed phylogenetic exploration and quantitative analyses of gut microbiome and improved our current understanding of the gut microbiota in health and disease. Its role in obesity and its changes following bariatric surgery have been highlighted in several studies. According to current literature, obesity is linked to a particular microbiota profile that grants the host an augmented potential for calorie release, while limited diversity of gut microbiome has also been observed. Moreover, bariatric surgery procedures represent effective interventions for sustained weight loss and restore a healthier microbiota, contributing to the observed fat mass reduction and lean mass increase. However, newer evidence has shown that gut microbiota is only partially recovered following bariatric surgery. Moreover, several targets including FGF15/19 (a gut-derived peptide), could be responsible for the favorable metabolic changes of bariatric surgery. More randomized controlled trials and larger prospective studies that include well-defined cohorts are required to better identify associations between gut microbiota, obesity, and bariatric surgery.

Bacteriocin-Producing Probiotic Lactic Acid Bacteria in Controlling Dysbiosis of the Gut Microbiota

Several strains of lactic acid bacteria are potent probiotics and can cure a variety of diseases using different modes of actions. These bacteria produce antimicrobial peptides, bacteriocins, which inhibit or kill generally closely related bacterial strains and other pathogenic bacteria such as Listeria, Clostridium, and Salmonella. Bacteriocins are cationic peptides that kill the target cells by pore formation and the dissipation of cytosolic contents, leading to cell death. Bacteriocins are also known to modulate native microbiota and host immunity, affecting several health-promoting functions of the host. In this review, we have discussed the ability of bacteriocin-producing probiotic lactic acid bacteria in the modulation of gut microbiota correcting dysbiosis and treatment/maintenance of a few important human disorders such as chronic infections, inflammatory bowel diseases, obesity, and cancer.

Implications of microbe-mediated crosstalk in the gut: Impact on metabolic diseases

Metabolic diseases continue to afflict most of the U.S. population. Advancements in gut microbiota research have led to the discovery of various functional roles of microorganisms that influence the development of obesity and co-morbidities including type 2 diabetes, non-alcoholic fatty liver disease and cardiovascular disease. Many mechanisms behind these host-microbe interactions stem from processes involving the intestinal epithelium including lipid metabolism. Thus, the purpose of this review is to discuss gut microbe-mediated changes in intestinal physiology and lipid metabolism that contribute to obesity, type 2 diabetes, non-alcoholic fatty liver disease and cardiovascular disease. Within each disease state, the causal role of bacteria in both driving disease development and protecting against metabolic disease will be discussed.

The Obesogenic and Glycemic Effect of Bariatric Surgery in a Family with a Melanocortin 4 Receptor Loss-of-Function Mutation

We report the long-term response to bariatric surgery in a singular family of four adolescents with severe obesity (41–82 kg/m2), homozygous for the C271R loss-of-function mutation in the melanocortin 4 receptor (MC4R), and three adults heterozygous for the same mutation. All patients had similar sociodemographic backgrounds and were followed for an average of 7 years. Three of the four homozygous patients regained their full weight (42–77 kg/m2), while the fourth lost weight but remained obese with a body mass index of 60 kg/m2. Weight regain was associated with relapse of most comorbidities, yet hyperglycemia did not relapse or was delayed. A1c levels were reduced in homozygous and heterozygous patients. The long-term follow-up data on this very unique genetic setting show that weight loss and amelioration of obesity following bariatric surgery require active MC4R signaling, while the improvement in glycemia is in part independent of weight loss. The study validates animal models and demonstrates the importance of biological signaling in the regulation of weight, even after bariatric surgery.

Gut microbiota in bariatric surgery

Gut microbes share a symbiotic relationship with humans and perform several metabolic and physiological functions essential for human survival. It has been established in several scientific studies that obesity and other metabolic complications are always associated with disturbed gut microbiota profile, also called gut dysbiosis. In recent years, bariatric surgery has become a treatment of choice for weight loss, and it forms an important part of obesity management strategies across the globe. Interestingly, bariatric surgery has been shown to alter gut microbiota profile and synthesize short-chain fatty acids by gut microbes. In other words, gut microbes play a crucial role in better clinical outcomes associated with bariatric surgery. In addition, gut microbes are important in reducing weight and lowering the adverse events post-bariatric surgery. Therefore, several prebiotics, probiotics and postbiotics are recommended for patients who underwent bariatric surgery procedures for better clinical outcomes. The present review aims to understand the possible association between gut microbes and bariatric surgery and present scientific evidence showing the beneficial role of gut microbes in improving therapeutic outcomes of bariatric surgery.

Metabolic Profile and Metabolite Analyses in Extreme Weight Responders to Gastric Bypass Surgery

Background: Roux-en-Y gastric bypass (RYGB) surgery belongs to the most frequently performed surgical therapeutic strategies against adiposity and its comorbidities. However, outcome is limited in a substantial cohort of patients with inadequate primary weight loss or considerable weight regain. In this study, gut microbiota composition and systemically released metabolites were analyzed in a cohort of extreme weight responders after RYGB. Methods: Patients (n = 23) were categorized based on excess weight loss (EWL) at a minimum of two years after RYGB in a good responder (EWL 93 ± 4.3%) or a bad responder group (EWL 19.5 ± 13.3%) for evaluation of differences in metabolic outcome, eating behavior and gut microbiota taxonomy and metabolic activity. Results: Mean BMI was 47.2 ± 6.4 kg/m² in the bad vs. 26.6 ± 1.2 kg/m² in the good responder group (p = 0.0001). We found no difference in hunger and satiety sensation, in fasting or postprandial gut hormone release, or in gut microbiota composition between both groups. Differences in weight loss did not reflect in metabolic outcome after RYGB. While fecal and circulating metabolite analyses showed higher levels of propionate (p = 0.0001) in good and valerate (p = 0.04) in bad responders, respectively, conjugated primary and secondary bile acids were higher in good responders in the fasted (p = 0.03) and postprandial state (GCA, p = 0.02; GCDCA, p = 0.02; TCA, p = 0.01; TCDCA, p = 0.02; GDCA, p = 0.05; GUDCA, p = 0.04; TLCA, p = 0.04). Conclusions: Heterogenous weight loss response to RYGB surgery separates from patients’ metabolic outcome, and is linked to unique serum metabolite signatures post intervention. These findings suggest that the level of adiposity reduction alone is insufficient to assess the metabolic success of RYGB surgery, and that longitudinal metabolite profiling may eventually help us to identify markers that could predict individual adiposity response to surgery and guide patient selection and counseling.

Domestic Environment and Gut Microbiota: Lessons from Pet Dogs

Accumulating data show the involvement of intestinal microbiota in the development and maintenance of numerous diseases. Many environmental factors influence the composition and function of the gut microbiota. An animal model subjected to the same environmental constraints that will allow better characterization of the microbiota–host dialogue is awaited. The domestic dog has physiological, dietary and pathological characteristics similar to those of humans and shares the domestic environment and lifestyle of its owner. This review exposes how the domestication of dogs has brought them closer to humans based on their intrinsic and extrinsic similarities which were discerned through examining and comparing the current knowledge and data on the intestinal microbiota of humans and canines in the context of several spontaneous pathologies, including inflammatory bowel disease, obesity and diabetes mellitus.