Obesity, diabetes, and gut microbiota: the hygiene hypothesis expanded?

Gut microbiota: An intermediary between metabolic syndrome and cognitive deficits in schizophrenia

Gut microbiome interacts with the central nervous system tract through the gut-brain axis. Such communication involves neuronal, endocrine, and immunological mechanisms, which allows for the microbiota to affect and respond to various behaviors and psychiatric conditions. In addition, the use of atypical antipsychotic drugs (AAPDs) may interact with and even change the abundance of microbiome to potentially cause adverse effects or aggravate the disorders inherent in the disease. The regulate effects of gut microbiome has been described in several psychiatric disorders including anxiety and depression, but only a few reports have discussed the role of microbiota in AAPDs-induced Metabolic syndrome (MetS) and cognitive disorders. The following review systematically summarizes current knowledge about the gut microbiota in behavior and psychiatric illness, with the emphasis of an important role of the microbiome in the metabolism of schizophrenia and the potential for AAPDs to change the gut microbiota to promote adverse events. Prebiotics and probiotics are microbiota-management tools with documented efficacy for metabolic disturbances and cognitive deficits. Novel therapies for targeting microbiota for alleviating AAPDs-induced adverse effects are also under fast development.

Oxidative Stress in Non-alcoholic Fatty Liver Disease. An Updated Mini Review

Non-alcoholic fatty liver disease (NAFLD) is a challenging disease caused by multiple factors, which may partly explain why it remains still orphan of an adequate therapeutic strategy. Herein we focus on the interplay between oxidative stress (OS) and the other causal pathogenetic factors. Different reactive oxygen species (ROS) generators contribute to NAFLD inflammatory and fibrotic progression, which is quite strictly linked to the lipotoxic liver injury from fatty acids and/or a wide variety of their biologically active metabolites in the context of either a two-hit or a (more recent) multiple parallel hits theory. An antioxidant defense system is usually able to protect hepatic cells from damaging effects caused by ROS, including those produced into the gastrointestinal tract, i.e., by-products generated by usual cellular metabolic processes, normal or dysbiotic microbiota, and/or diet through an enhanced gut–liver axis. Oxidative stress originating from the imbalance between ROS generation and antioxidant defenses is under the influence of individual genetic and epigenetic factors as well. Healthy diet and physical activity have been shown to be effective on NAFLD also with antioxidant mechanisms, but compliance to these lifestyles is very low. Among several considered antioxidants, vitamin E has been particularly studied; however, data are still contradictory. Some studies with natural polyphenols proposed for NAFLD prevention and treatment are encouraging. Probiotics, prebiotics, diet, or fecal microbiota transplantation represent new therapeutic approaches targeting the gut microbiota dysbiosis. In the near future, precision medicine taking into consideration genetic or environmental epigenetic risk factors will likely assist in further selecting the treatment that could work best for a specific patient.

Trimethylamine N-oxide (TMAO) in human health

Due to numerous links between trimethylamine-N-oxide (TMAO) and various disorders and diseases, this topic is very popular and is often taken up by researchers. TMAO is a low molecular weight compound that belongs to the class of amine oxides. It is formed by the process of oxidation of trimethylamine (TMA) by the hepatic flavin monooxygenases (FMO1 and FMO3). TMAO is mainly formed from nutritional substrates from the metabolism of phosphatidylcholine/choline, carnitine, betaine, dimethylglycine, and ergothioneine by intestinal microflora in the colon. Its level is determined by many factors, such as age, gender, diet, intestinal microflora composition, kidney function, and also liver flavin monooxygenase activity. Many studies report a positive relationship between the level of TMAO concentration and the development of various diseases, such as cardiovascular diseases and cardiorenal disorders, including atherosclerosis, hypertension, ischemic stroke, atrial fibrillation, heart failure, acute myocardial infarction, and chronic kidney disease, and also diabetes mellitus, metabolic syndrome, cancers (stomach, colon), as well as neurological disorders. In this review, we have summarized the current knowledge on the effects of TMAO on human health, the relationship between TMAO and intestinal microbiota, the role of TMAO in different diseases, and current analytical techniques used in TMAO determination in body fluids.

Insoluble dietary fiber derived from brown seaweed Laminaria japonica ameliorate obesity-related features via modulating gut microbiota dysbiosis in high-fat diet-fed mice

Gut microbiota (GM) is considered to play an important role in obesity. Additionally, the impact of dietary fiber (DF) consumption on GM has been well established. Brown seaweeds are known to be a rich source of DF. However, the effect of insoluble DFs (IDFs) alone from brown seaweed on obesity and GM remains to be determined. This study investigated the effect of IDFs prepared from Laminaria japonica Aresch on high-fat diet (HFD)-induced obesity and GM dysbiosis in mice. Although HFD-induced body weight gain was not significantly attenuated by the IDF treatment, HFD-induced liver injury was ameliorated, and the HFD-elevated serum cholesterol concentration and glucose level of obese mice were significantly lowered. IDF treatment significantly modulated the GM composition disturbed by the HFD. It was found that 5% IDFs restored the GM to a very similar composition to that in the normal mice. The relative abundance of Akkermansia genus was decreased by >300-fold in HFD-fed mice, and it was fully restored by 5% IDF administration. Akkermansia muciniphila, a short-chain fatty acid producer, was identified as a marker species in both control and high-dose IDF groups. Furthermore, IDFs significantly restored the HFD-reduced acetate and propionate levels in the cecal content. In conclusion, the beneficial effect of IDFs derived from L. japonica on obesity was confirmed in mice, and the underlying mechanism may be associated with the modulation of GM composition, possibly through the enrichment of Akkermansia.

A pilot study on the relationship between Lactobacillus, Bifidibactrium counts and inflammatory factors following exercise training

BACKGROUND

The current pilot study was carried out to examine the effect of aerobic exercise on Lactobacillus and Bifidobacterium as a function of weight loss and cytokine changes in overweight women.

MATERIAL AND METHODS

Eighteen women with excessive weight (age = 19-30 years) were randomly assigned into exercise (10 weeks, aerobic exercise training, 3 sessions/week) and control groups. Lactobacillus and Bifidobacterium in stool and inflammatory factors in blood were evaluated before and after the intervention.

RESULTS

The intervention induced significant improvements in body weight and in V_O2 peak. There were significant time effects on Lactobacillus (p = .016) and significant time*exercise interaction effects on Bifidobacterium (p = .025). Lactobacillus and Bifidobacterium changes were negatively associated with body weight and IL-6 levels, respectively.

CONCLUSIONS

The current results indicate that exercise training associated with weight loss can increase specific bacteria in people with excessive weight. Changes in Lactobacillus and Bifidobacterium were not significantly associated with cytokines.

Gut microbiota and their metabolites in the progression of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder worldwide. It comprises a spectrum of conditions that range from steatosis to non-alcoholic steatohepatitis, with progression to cirrhosis and hepatocellular carcinoma. Currently, there is no FDA-approved pharmacological treatment for NAFLD. The pathogenesis of NAFLD involves genetic and environmental/host factors, including those that cause changes in intestinal microbiota and their metabolites. In this review, we discuss recent findings on the relationship(s) of microbiota signature with severity of NAFLD and the role(s) microbial metabolites in NAFLD progression. We discuss how metabolites may affect NAFLD progression and their potential to serve as biomarkers for NAFLD diagnosis or therapeutic targets for disease management.

MiR-26a regulated adipogenic differentiation of ADSCs induced by insulin through CDK5/FOXC2 pathway

OBJECTIVE

Obesity is associated with an increased risk of developing insulin resistance and type 2 diabetes, since insulin can induce adipogenic differentiation of human adipose-derived stem cells (ADSCs). MiR-26a was reported to be highly expressed in ADSCs under induction and Forkhead box C2 (FOXC2), as a key substrate of cyclin-dependent kinase 5 (CDK5) could inhibit white adipocyte differentiation, which was mediated by miR-26a. However, the relationship between miR-26a and CDK5/FOXC2 during ADSCs differentiation remains unknown. We want to verify the regulated mechanism of miR-26a/CDK5/FOXC2 axis participating in the adipogenic differentiation of ADSCS.

METHODS

ADSCs were isolated and verified by flow cytometry. Oil Red O staining was performed to assess the capacity for adipogenic differentiation of ADSCs. The proliferation ability of ADSCs was verified by MTT assay. The expression of miR-26a, peroxisome proliferator-activated receptors γ (PPARγ), CDK5, and FOXC2 were tested by qRT-PCR and Western blot, and the relationship between miR-26a and CDK5 was verified by dual-luciferase reporter gene assay.

RESULTS

MiR-26a and PPARγ were upregulated and CDK5 and FOXC2 were downregulated during adipogenic differentiation of ADSCs. Knockdown of miR-26a or overexpression of CDK5 could inhibit adipogenic differentiation of ADSCs induced by insulin. MiR-26a could directly target CDK5 and the effect of miR-26a inhibitor on adipogenic differentiation of ADSCs could be blocked by si-CDK5.

CONCLUSION

We demonstrated that miR-26a regulated insulin-induced adipogenic differentiation of ADSCs by regulating CDK5/FOXC2 pathway, which could provide the key to a comprehensive mechanistic understanding of obesity and type 2 diabetes.

The Potential Roles of Very Low Calorie, Very Low Calorie Ketogenic Diets and Very Low Carbohydrate Diets on the Gut Microbiota Composition

Several studies have described a strong correlation between diet, weight loss, and gut microbiota composition. The aim of this review was to evaluate the potential effects of energy-restricted diets, namely very low calorie diets (VLCDs), very low calorie ketogenic diets (VLCKDs), and very low carbohydrate diets (VLCarbDs), on the composition of the gut microbiota in humans. We performed a literature search using the following terms (with their abbreviations or acronyms): "very low calorie diet", "very low calorie ketogenic diet", "very low carbohydrate diet", and "gut microbiota". Our search strategy retrieved nine eligible studies. Overall, VLCDs and VLCarbDs affected the Bacteroidetes to Firmicutes ratio in obese patients, leading to a reduction in short-chain fatty acid production by fecal microbiota associated with Clostridial cluster XIVa. This reduction particularly affected Roseburia and Eubacterium rectale, the two most abundant butyrate-producing bacteria in human feces. VLCKDs preserved the core fecal microbiome, but altered the composition of fecal microbial populations in relation to the plasma metabolome and fecal bile acid composition. In particular, VLCKD-induced weight loss resulted in a reduction in E. rectale and Roseburia, an increase in Christensenellaceae and Akkermansia while not all studies show a decrease in Faecalibacterium prausnitzii. Although very few studies have analyzed the effects of VLCarbDs and VLCDs on gut microbiota, significant diet-induced changes in fecal microbiota composition have been observed. Further studies are needed.

Anemarrhena asphodeloides modulates gut microbiota and restores pancreatic function in diabetic rats

Anemarrhena asphodeloides is an herb widely used to treat symptoms associated with diabetes in traditional Chinese medicine. However, its key components and metabolites have low bioavailability and poor host absorption. To clarify the anti-diabetic mechanism of A. asphodeloides extract (AAE), we examined the anti-diabetic effects of AAE in rats with diabetes induced by a high-fat diet and streptozotocin. Faeces levels of the main components and metabolites of AAE were significantly higher than levels in plasma, which indicated that gut microbiota might play important roles in its anti-diabetic effect. Microbiological studies showed that unabsorbed components increased the diversity of the gut microbiota, enriched potentially beneficial bacteria, and suppressed potentially harmful bacteria. In vitro studies showed that AAE promoted the proliferation of Blautia coccoides, a bacterium with positive implication for diabetes, in a dose-dependent manner. AAE also promoted pancreatic cell regeneration and restored the function of pancreatic islet cells via peroxiredoxin 4 overexpression. Overall, these results suggest that AAE alleviates diabetes via modulating gut microbiota and protein expression.

Modulating Gut Microbiota: An Emerging Approach in the Prevention and Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a progressive neuromuscular disorder characterized by demyelination of neurons of the central nervous system (CNS). The pathogenesis of the disorder is described as an autoimmune attack targeting the myelin sheath of nerve cell axons in the CNS. Available treatments only reduce the risk of relapse, prolonging the remissions of neurological symptoms and halt the progression of the disorder. Among the new ways of targeting neurological disorders, including MS, there is modulation of gut microbiota since the link between gut microbiota has been rethought within the term gut-brain axis. Gut microbiota is known to help the body with essential functions such as vitamin production and positive regulation of immune, inflammatory, and metabolic pathways. High consumption of saturated fatty acids, gluten, salt, alcohol, artificial sweeteners, or antibiotics is the responsible factor for causing gut dysbiosis. The latter can lead to dysregulation of immune and inflammatory pathways, which eventually results in leaky gut syndrome, systemic inflammation, autoimmune reactions, and increased susceptibility to infections. In modern medicine, scientists have mostly focused on the modulation of gut microbiota in the development of novel and effective therapeutic strategies for numerous disorders, with probiotics and prebiotics being the most widely studied in this regard. Several pieces of evidence from preclinical and clinical studies have supported the positive impact of probiotic and/or prebiotic intake on gut microbiota and MS. This review aims to link gut dysbiosis with the development/progression of MS, and the potential of modulation of gut microbiota in the therapeutics of the disease.

Metabolic networks of the human gut microbiota

The human gut microbiota controls factors that relate to human metabolism with a reach far greater than originally expected. Microbial communities and human (or animal) hosts entertain reciprocal exchanges between various inputs that are largely controlled by the host via its genetic make-up, nutrition and lifestyle. The composition of these microbial communities is fundamental to supply metabolic capabilities beyond those encoded in the host genome, and contributes to hormone and cellular signalling that support the dynamic adaptation to changes in food availability, environment and organismal development. Poor functional exchange between the microbial communities and their human host is associated with dysbiosis, metabolic dysfunction and disease. This review examines the biology of the dynamic relationship between the reciprocal metabolic state of the microbiota-host entity in balance with its environment (i.e. in healthy states), the enzymatic and metabolic changes associated with its imbalance in three well-studied diseases states such as obesity, diabetes and atherosclerosis, and the effects of bariatric surgery and exercise.

Alternations of gut microbiota composition in neonates conceived by assisted reproductive technology and its relation to infant growth

The gut microbiome in newborns may be strongly influenced by their intrinsic host microenvironmental factors (e.g., the gestational age) and has been linked to their short-term growth and potentially future health. It is yet unclear whether early microbiota composition is significantly different in newborns conceived by assisted reproductive technology (ART) when compared with those who were conceived spontaneously. Additionally, little is known about the effect of gut microbiota composition on weight gain in early infancy. We aimed to characterize the features and the determinants of the gut microbiome in ART newborns and to assess the impact of early microbiota composition on their weight gain in early infancy in mother-infant dyads enrolled in the China National Birth Cohort (CNBC). Among 118 neonates born by ART and 91 neonates born following spontaneous conception, we observed significantly reduced gut microbiota α-diversity and declined Bacteroidetes relative abundance in ART neonates. The microbiota composition of ART neonates was largely driven by specific ART treatments, hinting the importance of fetus intrinsic host microenvironment on the early microbial colonization. Following up these neonates for six months after their births, we observed the effects of gut microbiome composition on infant rapid weight gaining. Collectively, we identified features and determinants of the gut microbiota composition in ART neonates, and provided evidence for the importance of microbiota composition in neonatal growth.

Dietary Emulsifiers Alter Composition and Activity of the Human Gut Microbiota in vitro, Irrespective of Chemical or Natural Emulsifier Origin

The use of additives in food products has become an important public health concern. In recent reports, dietary emulsifiers have been shown to affect the gut microbiota, contributing to a pro-inflammatory phenotype and metabolic syndrome. So far, it is not yet known whether similar microbiome shifts are observable for a more diverse set of emulsifier types and to what extent these effects vary with the unique features of an individual's microbiome. To bridge this gap, we investigated the effect of five dietary emulsifiers on the fecal microbiota from 10 human individuals upon a 48 h exposure. Community structure was assessed with quantitative microbial profiling, functionality was evaluated by measuring fermentation metabolites, and pro-inflammatory properties were assessed with the phylogenetic prediction algorithm PICRUSt, together with a TLR5 reporter cell assay for flagellin. A comparison was made between two mainstream chemical emulsifiers (carboxymethylcellulose and P80), a natural extract (soy lecithin), and biotechnological emulsifiers (sophorolipids and rhamnolipids). While fecal microbiota responded in a donor-dependent manner to the different emulsifiers, profound differences between emulsifiers were observed. Rhamnolipids, sophorolipids, and soy lecithin eliminated 91 ± 0, 89 ± 1, and 87 ± 1% of the viable bacterial population after 48 h, yet they all selectively increased the proportional abundance of putative pathogens. Moreover, profound shifts in butyrate (-96 ± 6, -73 ± 24, and -34 ± 25%) and propionate (+13 ± 24, +88 ± 50, and +29 ± 16%) production were observed for these emulsifiers. Phylogenetic prediction indicated higher motility, which was, however, not confirmed by increased flagellin levels using the TLR5 reporter cell assay. We conclude that dietary emulsifiers can severely impact the gut microbiota, and this seems to be proportional to their emulsifying strength, rather than emulsifier type or origin. As biotechnological emulsifiers were especially more impactful than chemical emulsifiers, caution is warranted when considering them as more natural alternatives for clean label strategies.

Characterisation of gut microbiota of obesity and type 2 diabetes in a rodent model

Various studies have suggested that the gut microbiome interacts with the host and may have a significant role in the aetiology of obesity and Type 2 Diabetes (T2D). It was hypothesised that bacterial communities in obesity and T2D differ from control and compromise normal interactions between host and microbiota. Obesity and T2D were developed in rats by feeding a high-fat diet or a high-fat diet plus a single low-dose streptozotocin administration, respectively. The microbiome profiles and their metabolic potentials were established by metagenomic 16S rRNA sequencing and bioinformatics. Taxonomy and predicted metabolism-related genes in obesity and T2D were markedly different from controls and indeed from each other. Diversity was reduced in T2D but not in Obese rats. Factors likely to compromise host intestinal, barrier integrity were found in Obese and T2D rats including predicted, decreased bacterial butyrate production. Capacity to increase energy extraction via ABC-transporters and carbohydrate metabolism were enhanced in Obese and T2D rats. T2D was characterized by increased proinflammatory molecules. While obesity and T2D show distinct differences, results suggest that in both conditions Bacteroides and Blautia species were increased indicating a possible mechanistic link.

Multi-omics profiling highlights lipid metabolism alterations in pigs fed low-dose antibiotics

Background

In order to study the relations of hepatocellular functions, weight gain and metabolic imbalance caused by low-dose antibiotics (LDA) via epigenetic regulation of gene transcription, 32 weaned piglets were employed as animal models and randomly allocated into two groups with diets supplemented with 0 or LDA (chlorotetracycline and virginiamycin).

Results

During the 4 weeks of the experiment, LDA showed a clear growth-promoting effect, which was exemplified by the significantly elevated body weight and average daily gain. Promoter methylome profiling using liquid hybridization capture-based bisulfite sequencing (LHC-BS) indicated that most of the 745 differential methylation regions (DMRs) were hypermethylated in the LDA group. Several DMRs were significantly enriched in genes related with fatty acids metabolic pathways, such as FABP1 and PCK1. In addition, 71 differentially expressed genes (DEGs) were obtained by strand-specific transcriptome analysis of liver tissues, including ALOX15, CXCL10 and NNMT, which are three key DEGs that function in lipid metabolism and immunity and which had highly elevated expression in the LDA group. In accordance with these molecular changes, the lipidome analyses of serum by LC-MS identified 38 significantly differential lipids, most of which were downregulated in the LDA group.

Conclusions

Our results indicate that LDA could induce epigenetic and transcriptional changes of key genes and lead to enhanced efficiency of lipid metabolism in the liver.

Metagenomic analysis of the human microbiome reveals the association between the abundance of gut bile salt hydrolases and host health

Bile acid metabolism by the gut microbiome exerts both beneficial and harmful effects on host health. Microbial bile salt hydrolases (BSHs), which initiate bile acid metabolism, exhibit both positive and negative effects on host physiology. In this study, 5,790 BSH homologs were collected and classified into seven clusters based on a sequence similarity network. Next, the abundance and distribution of BSH in 380 metagenomes from healthy participants were analyzed. It was observed that different clusters occupied diverse ecological niches in the human microbiome and that the clusters with signal peptides were relatively abundant in the gut. Then, the association between BSH clusters and 12 human diseases was analyzed by comparing the abundances of BSH genes in patients (n = 1,605) and healthy controls (n = 1,540). The analysis identified a significant association between BSH gene abundance and 10 human diseases, including gastrointestinal diseases, obesity, type 2 diabetes, liver diseases, cardiovascular diseases, and neurological diseases. The associations were further validated by separate cohorts with inflammatory bowel diseases and colorectal cancer. These large-scale studies of enzyme sequences combined with metagenomic data provide a reproducible assessment of the association between gut BSHs and human diseases. This information can contribute to future diagnostic and therapeutic applications of BSH-active bacteria for improving human health.

Probiotics, Prebiotics, Synbiotics, Postbiotics, and Obesity: Current Evidence, Controversies, and Perspectives

PURPOSE OF REVIEW

In this review, we summarize current evidence on gut microbiome and obesity; we discuss the role of probiotics, prebiotics, synbiotics, and postbiotics in obesity prevention and management; and we highlight and analyze main limitations, challenges, and controversies of their use.

RECENT FINDINGS

Overall, the majority of animal studies and meta-analyses of human studies examining the use of probiotics and synbiotics in obesity has shown their beneficial effects on weight reduction and other metabolic parameters via their involvement in gut microbiota modulation. Bifidobacterium and Lactobacillus strains are still the most widely used probiotics in functional foods and dietary supplements, but next generation probiotics, such as Faecalibacterium prausnitzii, Akkermansia muciniphila, or Clostridia strains, have demonstrated promising results. On the contrary, meta-analyses of human studies on the use of prebiotics in obesity have yielded contradictory results. In animal studies, postbiotics, mainly short-chain fatty acids, may increase energy expenditure through induction of thermogenesis in brown adipose tissue as well as browning of the white adipose tissue. The main limitations of studies on biotics in obesity include the paucity of human studies; heterogeneity among the studied subgroups regarding age, gender, and lifestyle; and use of different agents with potential therapeutic effects in different formulations, doses, ratio and different pharmacodynamics/pharmacokinetics. In terms of safety, the supplementation with prebiotics, probiotics, and synbiotics has not been associated with serious adverse effects among immune-competent individuals, with the exception of the use of probiotics and synbiotics in immunocompromised patients. Further large-scale Randomized Controlled Trials (RCTs) in humans are required to evaluate the beneficial properties of probiotics, prebiotics, synbiotics, and postbiotics; their ideal dose; the duration of supplementation; and the durability of their beneficial effects as well as their safety profile in the prevention and management of obesity.

The Metabolic Effects of Pre-probiotic Supplementation After Roux-en-Y Gastric Bypass (RYGB) Surgery: a Prospective, Randomized Controlled Study

PURPOSE

Following Roux-en-Y gastric bypass (RYGB), positive alterations are observed in gut microbiota and intestinal peptides. Previous studies demonstrated similar alterations observed in cases when pre-probiotics are used without surgery. The aim of this trial was to evaluate the effectiveness of early use of pre-probiotics after RYGB.

MATERIAL AND METHODS

The operation and follow-up of the patients were performed at Istanbul University Medical Faculty. Thirty-two patients who had undergone RYGB were randomized to pre-probiotic group (PreProBG, n = 16; 200 g/day yogurt plus 10 g/day inulin+oligofructose) and probiotic group (ProBG, n = 16; 200 g/day yogurt only) for 6 months. Blood samples (glucose, insulin, A1c, GLP-1, PYY), anthropometric measurements, and appetite ratings have been evaluated at baseline and 3 (m3) and 6 (m6) months after RYGB.

RESULTS

Initial anthropometric measurements and appetite ratings decreased significantly after surgery and there were no significant differences between the groups. The decrease of area under the curve(insulin) was less and has a positive correlation with the changes in anthropometric measurements in PreProBG. GLP-1 and PYY which increased dramatically after surgery in all patients were higher in PreProBG. But this increase had a negative correlation with the changes in anthropometric measurements during the study.

CONCLUSION

Increased insulin, GLP-1, and PYY secretion was more enhanced by pre-probiotic use in early postoperative period. But this increase not only in anthropometric measurements but also in appetite ratings affects negatively, contrary to expectations. In summary, it should be investigated with new studies that use of pre-probiotics in the late postoperative period may be more effective in patients with weak insulin and incretin response and therefore insufficient weight loss. Trial Registration clinicaltrials.gov Identifier: NCT03517345.

Liver Steatosis, Gut-Liver Axis, Microbiome and Environmental Factors. A Never-Ending Bidirectional Cross-Talk

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and parallels comorbidities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. Recent studies describe the presence of NAFLD in non-obese individuals, with mechanisms partially independent from excessive caloric intake. Increasing evidences, in particular, point towards a close interaction between dietary and environmental factors (including food contaminants), gut, blood flow, and liver metabolism, with pathways involving intestinal permeability, the composition of gut microbiota, bacterial products, immunity, local, and systemic inflammation. These factors play a critical role in the maintenance of intestinal, liver, and metabolic homeostasis. An anomalous or imbalanced gut microbial composition may favor an increased intestinal permeability, predisposing to portal translocation of microorganisms, microbial products, and cell wall components. These components form microbial-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs), with potentials to interact in the intestine lamina propria enriched in immune cells, and in the liver at the level of the immune cells, i.e., Kupffer cells and stellate cells. The resulting inflammatory environment ultimately leads to liver fibrosis with potentials to progression towards necrotic and fibrotic changes, cirrhosis. and hepatocellular carcinoma. By contrast, measures able to modulate the composition of gut microbiota and to preserve gut vascular barrier might prevent or reverse NAFLD.

Fecal microbiota transplantation from high caloric-fed donors alters glucose metabolism in recipient mice, independently of adiposity or exercise status

Studies suggest the gut microbiota contributes to the development of obesity and metabolic syndrome. Exercise alters microbiota composition and diversity and is protective of these maladies. We tested whether the protective metabolic effects of exercise are mediated through fecal components through assessment of body composition and metabolism in recipients of fecal microbiota transplantation (FMT) from exercise-trained (ET) mice fed normal or high-energy diets. Donor C57BL/6J mice were fed a chow or high-fat, high-sucrose diet (HFHS) for 4 wk to induce obesity and glucose intolerance. Mice were divided into sedentary (Sed) or ET groups (6 wk treadmill-based ET) while maintaining their diets, resulting in four donor groups: chow sedentary (NC-Sed) or ET (NC-ET) and HFHS sedentary (HFHS-Sed) or ET (HFHS-ET). Chow-fed recipient mice were gavaged with feces from the respective donor groups weekly, creating four groups (NC-Sed-R, NC-ET-R, HFHS-Sed-R, HFHS-ET-R), and body composition and metabolism were assessed. The HFHS diet led to glucose intolerance and obesity in the donors, whereas exercise training (ET) restrained adiposity and improved glucose tolerance. No donor group FMT altered recipient body composition. Despite unaltered adiposity, glucose levels were disrupted when challenged in mice receiving feces from HFHS-fed donors, irrespective of donor-ET status, with a decrease in insulin-stimulated glucose clearance into white adipose tissue and large intestine and specific changes in the recipient's microbiota composition observed. FMT can transmit HFHS-induced disrupted glucose metabolism to recipient mice independently of any change in adiposity. However, the protective metabolic effect of ET on glucose metabolism is not mediated through fecal factors.

Human microbiome and prostate cancer development: current insights into the prevention and treatment

The huge communities of microorganisms that symbiotically colonize humans are recognized as significant players in health and disease. The human microbiome may influence prostate cancer development. To date, several studies have focused on the effect of prostate infections as well as the composition of the human microbiome in relation to prostate cancer risk. Current studies suggest that the microbiota of men with prostate cancer significantly differs from that of healthy men, demonstrating that certain bacteria could be associated with cancer development as well as altered responses to treatment. In healthy individuals, the microbiome plays a crucial role in the maintenance of homeostasis of body metabolism. Dysbiosis may contribute to the emergence of health problems, including malignancy through affecting systemic immune responses and creating systemic inflammation, and changing serum hormone levels. In this review, we discuss recent data about how the microbes colonizing different parts of the human body including urinary tract, gastrointestinal tract, oral cavity, and skin might affect the risk of developing prostate cancer. Furthermore, we discuss strategies to target the microbiome for risk assessment, prevention, and treatment of prostate cancer.

Effect of Bacillus-direct-fed microbial on leaky gut, serum peptide YY concentration, bone mineralization, and ammonia excretion in neonatal female turkey poults fed with a rye-based diet

Rye is high in nonstarch polysaccharides (NSP), a complex carbohydrate which cannot be digested by poultry as they lack the endogenous enzymes to do so. Exogenous carbohydrases must therefore be supplemented to avoid the antinutritional effects associated with a high NSP diet. The objectives of the present study were to evaluate the effects of a rye-based diet with and without supplementation of a Bacillus direct-fed microbial (DFM) on body weight, bone mineralization, and leaky gut, as well as its role on influencing serum concentrations of peptide YY (PPY) and the ammonia concentration in turkey manure. Two independent trials were conducted. In each experiment, day-of-hatch female turkey poults were neck tagged and randomly assigned to either a control rye-based diet or a rye-based diet supplemented with the DFM (n = 25 birds/group). At 10 days-of-age, poults in both groups were administered with an appropriate dose of fluorescein isothiocyanate-dextran (FITC-d) by oral gavage. One hour later, all poults were euthanized. Blood was collected to evaluate serum FITC-d and PPY concentrations. Furthermore, in Trial 2 only, both tibias were removed for assessment of bone parameters, and turkey manure was collected to evaluate physicochemical analysis. In both trials, poults treated with the DFM showed a significant increase (P < 0.05) in body weight and body weight gain as compared with control nontreated poults. Poults that received the DFM also had a significant reduction in serum levels of PPY and FITC-d when compared with control nontreated poults. In Trial 2, turkeys treated with the DFM had a substantial increase in tibia strength, tibia diameter, total ash, calcium, and phosphorus when compared with control nontreated turkeys. Their manure was also shown to have a significant reduction in the concentration of ammonia. This is the first report of a commercial DFM reducing the concentration of this compound in turkey manure. In summary, the results of the present study confirm that turkeys fed with a rye-based diet have a significant increase in gut permeability, a reduced body weight, and decreased bone mineralization when compared with turkeys fed with the DFM. Turkeys that received the rye-based diet supplemented with the Bacillus-DFM also had a significant reduction in the serum concentration of PPY when compared with control turkeys. This finding suggests a possible prebiotic effect of rye, warranting future studies to test this effect. Further studies to evaluate the microbiota diversity, as well as the concentration of ceca short-chain fatty acids, are also necessary to confirm the reliability of PPY as a potential metabolomic biomarker in poultry.

Dysbiosis of gut microbiota in adult idiopathic membranous nephropathy with nephrotic syndrome

BACKGROUND

Gut bacterial microbiota is altered in patients with chronic kidney disease (CKD) and those on dialysis. However, it is not yet clear what bacterial composition changes occur in patients with idiopathic nephrotic syndrome (INS). We present in this report the changes in gut bacterial microbiota in INS patients with membranous nephropathy.

METHODS

A total of 158 individuals were recruited for this study. Of these, 80 patients had stage 3-5 CKD without nephrotic syndrome (CKD group), 48 patients had INS and pathological diagnosis of membranous nephropathy (INS group), and 30 were age- and sex-matched healthy controls (HC group). The gut microbiome composition was analyzed using a 16S ribosomal RNA gene-based sequencing protocol.

RESULTS

The results indicate that the nephrotic syndrome patients had a significantly different alpha and beta diversity compared with the CKD group and HC group (P < 0.01). At the phylum level, the INS patients showed increased Fusobacteria and Proteobacteria but reduced Firmicutes when compared with the HC group. At the genus level, Megamonas, Megasphaera, Akkermansia, and the butyrate-producing bacteria Lachnospira, Roseburia, and Fusobacterium were more abundant in the HC group (LDA score > 3) than the CKD and INS group. Fecal organic acid analysis revealed significantly lower quantities of propionate acid and butyric acid in INS than the HC group (P < 0.05). Compared with the HC group, we found that Parabacteroides was increased in CKD and INS patients. In addition, Oscillospira and Ruminococcus were more abundant in CKD patients than in the other two groups (LDA score > 3). At the genus level, ten bacterial taxa were more prevalent in the HC group. Providencia and Myroides were more prevalent in INS patients.

CONCLUSION

Our findings highlight that, INS patients had a significantly different alpha and beta diversity and decreased gut microbiota-derived short-chain fatty acids, such as butyrate. However, large-scale prospective studies should be performed to identify the cause and effect factors of these changes in the microbiota in INS patients.

Effect of succinic acid on the organism of mice and their intestinal microbiota against the background of excessive fat consumption

Succinic acid and its salts (succinates) positively affect the oxygenation of the internal environment, stabilize the structure and functional activity of mitochondria, and normalize the ion metabolism in the cell. Separate clinical studies and experimental surveys confirmed that having low toxicity succinic acid has well-manifested antioxidant, immunostimulating, adaptogenic properties. In this study, we determined the influence of succinic acid on the organism of laboratory animals against the backround of high-fat diet: the changes in body weight, indices of the mass of the internal organs, blood parameters and the changes in the intestinal microbiota were determined. For the experiment, we formed three experimental and three control groups of male white mice. The animals of the control group received 0.5% solution of succinic acid instead of water. In the experiment, we determined that succinic acid has no effect on the intensity of growth of weight of young mice against the background of excessive fat in their diet. Excessive consumption of fat by male mice leads to mainly disorders in the functioning of the liver, excretory and the immune systems. High-fat diet of mice is accompanied by impaired hepatic function, manifested in sharp hypoproteinemia due to globulins, increase in the activity of hepatic enzymes against the background of reduced activity of alkaline phosphatase, increase in the level of bilirubin, and decrease in glucose. Excess of fat in the diet leads to malfunctioning of the excretory system, manifested in the reduced index of kidneys’ weight, high content of creatinine and reduced level of urea in the blood. Addition of succinic acid has a positive effect on the functional condition of the liver and the kidneys, especially noticeable during long-term intake. High-fat diet causes disorders in the functioning of the organs of blood circulation and immune protection, accompanied by decrease in the relative mass of the thymus and spleen, low content of hemoglobin and the number of erythrocytes, but has no significant effect on the content of other cellular elements in the blood. By the middle of the experiment, succinic acid had exacerbated these processes compared to the control, but by the end of the experiment, by contrast, these processes were alleviated. Addition of the succinic acid to high-fat diet contributed to the change in the quantitative composition of the main representatives of the obligatory microbiota (Bifidobacterium spp., Lactobacillus spp. and typical Escherichia coli) in the laboratory animals. Such changes in the intestinal microbiota may lead to such consequences as reproduction of the facultative microflora, and, thus, development of various diseases.

Bacterial diversity in the intestinal mucosa of mice fed with Asparagus extract under high-fat diet condition

The purpose of this study is to determine the effect of Asparagus on bacterial diversity in the intestinal mucosa of mice fed with high-fat diet, thus providing theoretical basis for the development and research of Asparagus products. Twelve healthy male Kunming mice and twelve healthy female Kunming mice were chosen and randomly divided into normal group, model group, Asparagus group, and lipid-lowering decoction group, with six mice in each group. After establishing the models of mice fed with high-fat diet through feeding with high-fat diet, the mice in the Asparagus group were gavaged with Asparagus juice, those in the lipid-lowering decoction group were gavaged with lipid-lowering decoction, and those in the normal group and high-fat diet group were gavaged with the equal amount of distilled water. Intestinal mucosa from the jejunum to ileum were collected, and DNA was extracted from each mice. The characteristics of the intestinal microbial species were analyzed by PacBio Sequel-based 16S rRNA sequencing. Result showed that the total OTU reached 1559 in the normal group, 1750 in the high-fat diet group, 1795 in the lipid-Lowering decoction group, and 1635 in the Asparagus group, which indicated that the Asparagus juice could inhibit the total OUT of intestinal bacteria. The analysis on sample community diversity indicated that the richness, diversity, richness estimation, and diversity in the Asparagus Group, lipid-lowering decoction group, and normal group were lower than those in the high-fat diet group. Bacteriophyta classification analysis indicated that the relative abundance of Firmicutes, Bacteroidetes, and Actinobacteria in the Asparagus group was between that in the high-fat diet group and normal group. In conclusion, Asparagus can affect the diversity of bacteria in the intestinal mucosa of mice fed with high-fat diet, and achieve a lipid-lowering effect by regulating the intestinal microecology of mice fed with high-fat diet.

Caesarean delivery is associated with higher risk of overweight in the offspring: within-family analysis in the SUN cohort

BACKGROUND

Most studies assessing the association between caesarean delivery (CD) and childhood overweight/obesity have failed to account for important confounders, such as maternal prepregnancy body mass index (BMI) or the indication of the CD. Furthermore, within-family analyses have reported contradictory results. We aimed at evaluating the association between CD and offspring's risk of overweight/obesity while adjusting for important confounders and accounting for correlations between siblings.

METHODS

Women in the 'Seguimiento Universidad de Navarra' cohort provided structured information regarding their pregnancy history and their children's health through online cross-sectional questionnaires. We calculated adjusted differences in BMI z-score and risk ratios (RR) for offspring's overweight/obesity associated with CD, with hierarchical models to account for correlations between siblings. We also performed a within-family analysis in 341 siblings who were discordant in delivery mode, using conditional multivariable logistic regression.

RESULTS

Among the 2791 children analysed, those born by CD had higher average BMI z-scores (difference: 0.17; 95% CI 0.07 to 0.27) and higher risk of overweight/obesity (RR: 1.32, 95% CI 1.05 to 1.65) than children born vaginally. The association did not differ by maternal characteristics or offspring's age strata, and the results were consistent in sensitivity analyses. Furthermore, within-family analysis showed that children born by CD had 2.67-fold higher risk of overweight/obesity (95% CI 1.10 to 5.12) than their peers born vaginally.

CONCLUSION

Children born by CD have higher average BMI z-scores and higher risk of overweight/obesity than children born vaginally. The consistency of these findings across multiple approaches to address potential residual confounding likely suggests a true biological effect.

Gut Microbiota, Its Role in Induction of Alzheimer's Disease Pathology, and Possible Therapeutic Interventions: Special Focus on Anthocyanins

The human gut is a safe environment for several microbes that are symbiotic and important for the wellbeing of human health. However, studies on gut microbiota in different animals have suggested that changes in the composition and structure of these microbes may promote gut inflammation by releasing inflammatory cytokines and lipopolysaccharides, gut-wall leakage, and may affect systemic inflammatory and immune mechanisms that are important for the normal functioning of the body. There are many factors that aid in the gut’s dysbiosis and neuroinflammation, including high stress levels, lack of sleep, fatty and processed foods, and the prolonged use of antibiotics. These neurotoxic mechanisms of dysbiosis may increase susceptibility to Alzheimer’s disease (AD) and other neurodegenerative conditions. Therefore, studies have recently been conducted to tackle AD-like conditions by specifically targeting gut microbes that need further elucidation. It was suggested that gut dyshomeostasis may be regulated by using available options, including the use of flavonoids such as anthocyanins, and restriction of the use of high-fatty-acid-containing food. In this review, we summarize the gut microbiota, factors promoting it, and possible therapeutic interventions especially focused on the therapeutic potential of natural dietary polyflavonoid anthocyanins. Our study strongly suggests that gut dysbiosis and systemic inflammation are critically involved in the development of neurodegenerative disorders, and the natural intake of these flavonoids may provide new therapeutic opportunities for preclinical or clinical studies.

Bifidobacterium pseudolongum reduces triglycerides by modulating gut microbiota in mice fed high-fat food

Obesity has become a growing concern around the world. The purpose of this study was to investigate the potential benefit of Bifidobacterium pseudolongum (B. pseudolongum) on obesity, gut microbiota, and its physiological mechanism. The obese mice model was established with a high-fat diet (HFD), and the treatment were used the strain B. pseudolongum. We investigated the changes in fat content, plasma metabolites and gut microbiota on obese mice and B. pseudolongum treated obese mice. We found that B. pseudolongum treatment significantly decreased the body mass (about 12 %), plasma triglycerides (about 12.4 %), gross energy intake (about 12.8 %), and visceral fat (about 26.5 %) in obese mice. Further, High-throughput pyrosequencing of the 16S rRNA demonstrated that B. pseudolongum treatment markedly recovered the gut microbiota dysbiosis in obese mice, including the diversity of microbiota and the ratio of Firmicutes to Bacteroidetes. B. pseudolongum treatment increased the abundance of the bacterial genus Butyricimonas and Bifidobacterium. Therefore, B. pseudolongum may have therapeutic potential for the treatment of diet-induced obesity (DIO). B. pseudolongum treatment could change host gut microbiota and provide benefits to host digestive processes that mitigate metabolic diseases.

Association of Birth by Cesarean Delivery With Obesity and Type 2 Diabetes Among Adult Women

Importance

Cesarean delivery is associated with an increased risk of childhood obesity in offspring. However, whether this increased risk also includes obesity-associated conditions remains unclear.

Objective

To evaluate the association of birth by cesarean delivery with offspring's risks of obesity and type 2 diabetes in adulthood.

Design, Setting, and Participants

This prospective cohort study compared the incidence of obesity and type 2 diabetes between birth by cesarean delivery and vaginal delivery among 33 226 women participating in the Nurses' Health Study II who were born between 1946 and 1964, with follow-up through the end of the 2013-2015 follow-up cycle. Participants' mothers provided information on mode of delivery and pregnancy characteristics. Participants provided information every 2 years on weight and diagnosis of type 2 diabetes. Relative risks of obesity and type 2 diabetes were estimated using log-binomial and proportional hazards regression accounting for maternal body mass index and other confounding factors. Statistical analysis was performed from June 2017 to December 2019.

Exposure

Birth by cesarean delivery compared with birth by vaginal delivery.

Main Outcomes and Measures

Risk of obesity and incidence of type 2 diabetes.

Results

At baseline, the participants' mean (SD) age was 33.8 (4.6) years (range, 24.0-44.0 years). A total of 1089 of the 33 226 participants (3.3%) were born by cesarean delivery. After 1 913 978 person-years of follow-up, 12 156 (36.6%) women were obese and 2014 (6.1%) had received a diagnosis of type 2 diabetes. Women born by cesarean delivery were more likely to be classified as obese and to have received a diagnosis of type 2 diabetes during follow-up. The multivariable-adjusted relative risk of obesity among women born by cesarean vs vaginal delivery was 1.11 (95% CI, 1.03-1.19). The multivariable-adjusted hazard ratio for type 2 diabetes among women born by cesarean vs vaginal delivery was 1.46 (95% CI, 1.18-1.81); this association remained significant after additional adjustment for participant's own body mass index (relative risk, 1.34 [95% CI, 1.08-1.67]). These associations persisted when analyses were restricted to women at low risk of cesarean delivery based on maternal characteristics.

Conclusions and Relevance

This study suggests that women born by cesarean delivery may have a higher risk than women born by vaginal delivery of being obese and developing type 2 diabetes during adult life.

Epidemiology, risk factors across the spectrum of age-related metabolic diseases

BACKGROUND

Population aging is dynamic process of increasing proportion of older adults in the total population, which is an inescapable result of decline in fertility rate and extension in life expectancy. Inevitably, age-related metabolic diseases, for example obesity, type 2 diabetes, metabolic syndrome, dyslipidemia, and nonalcoholic fatty liver disease, are becoming epidemic globally along with the demographic transition.

CONTENT

The review examines the literatures related to: 1) the epidemiology of age related metabolic diseases including obesity, type 2 diabetes, metabolic syndrome, dyslipidemia, and nonalcoholic fatty liver disease; and 2) the risk factors of age related metabolic diseases including genetic factors, diet, smoking, Physical activity, intestinal microbiota and environmental factors.

CONCLUSION

Population aging is becoming epidemic worldwide, resulting in increasing incidence and prevalence of a serious of age-related metabolic diseases. Both genetic and environmental factors contribute to the diseases, thus interventions targeting on these factors may have beneficial effect on the development of age-related metabolic diseases.

Linking gut microbiota with the human diseases

The human gut is rich in microbes. Therefore, it is of interest to document data to link known human diseases with the gut microbiota. Various factors like hormones, metabolites and dietary habitats are responsible for shaping the microbiota of the gut. Imbalance in the gut microbiota is responsible for the pathogenesis of various disease types including rheumatoid arthritis, different types of cancer, diabetes mellitus, obesity, and cardiovascular disease. We report a review of known data for the correction of dysbiosis (imbalance in microbe population) towards improved human health.

Gut Microbiota and Its Metabolites in Atherosclerosis Development

Gut microbiota metabolites have a great influence on host digestive function and body health itself. The effects of intestinal microbes on the host metabolism and nutrients absorption are mainly due to regulatory mechanisms related to serotonin, cytokines, and metabolites. Multiple studies have repeatedly reported that the gut microbiota plays a fundamental role in the absorption of bioactive compounds by converting dietary polyphenols into absorbable bioactive substances. Moreover, some intestinal metabolites derived from natural polyphenol products have more biological activities than their own fundamental biological functions. Bioactive like polyphenolic compounds, prebiotics and probiotics are the best known dietary strategies for regulating the composition of gut microbial populations or metabolic/immunological activities, which are called “three “p” for gut health”. Intestinal microbial metabolites have an indirect effect on atherosclerosis, by regulating lipid metabolism and inflammation. It has been found that the diversity of intestinal microbiota negatively correlates with the development of atherosclerosis. The fewer the variation and number of microbial species in the gut, the higher the risk of developing atherosclerosis. Therefore, the atherosclerosis can be prevented and treated from the perspective of improving the number and variability of gut microbiota. In here, we summarize the effects of gut metabolites of natural products on the pathological process of the atherosclerosis, since gut intestinal metabolites not only have an indirect effect on macrophage foaming in the vessel wall, but also have a direct effect on vascular endothelial cells.

Reduced environmental bacterial load during early development and gut colonisation has detrimental health consequences in Japanese quail

Gastrointestinal colonisation by commensal microbiota is essential for the health and well-being of the host. We aimed to evaluate the influence of a reduced bacterial load environment on microbiota development and maturation, and the possibility of targeted colonisation via at-hatch administration of a selected bacterial strain. Japanese quail (Coturnix japonica) were inoculated within 1 h of hatch with a freshly grown culture of a Lactobacillus agilis isolate derived from a healthy adult quail. Hatchlings were kept in a mouse isolator for one week and then housed between one and four weeks of age, with a flock of normally grown adult quail to expose the bacteria-restricted birds to normal commensal quail bacteria. The bacterial isolate used to inoculate the birds was found to completely dominate the microbiota of the intestine of L.agilis at-hatch inoculated birds. Despite 3 weeks of co-housing of the test birds with an adult flock harbouring normal rich gut microbiota, neither the Lactobacillus inoculated nor PBS inoculated birds reached the level of bacterial diversity seen in birds raised under normal conditions. Neither PBS nor Lactobacillus inoculated birds were able to adopt normal quail microbiota after one week of restricted exposure to bacteria, indicating that contact with diverse microbiota during the early days of gut development in birds is critical for the establishment of healthy intestinal community. Very early intervention in the form of a suitable bacterial probiotic inoculant immediately post-hatch protected birds grown in extreme hygiene conditions from developing anomalous gut microbiota and intestinal damage. Our data shows that it is possible to induce dominance of desired strain using simple timed manipulation.

Alteration of the gut microbiota associated with childhood obesity by 16S rRNA gene sequencing

Background

Obesity is a global epidemic in the industrialized and developing world, and many children suffer from obesity-related complications. Gut microbiota dysbiosis might have significant effect on the development of obesity. The microbiota continues to develop through childhood and thus childhood may be the prime time for microbiota interventions to realize health promotion or disease prevention. Therefore, it is crucial to understand the structure and function of pediatric gut microbiota.

Methods

According to the inclusion criteria and exclusion criteria, twenty-three normal weight and twenty-eight obese children were recruited from Nanjing, China. Genomic DNA was extracted from fecal samples. The V4 region of the bacterial 16S rDNA was amplified by PCR, and sequencing was applied to analyze the gut microbiota diversity and composition using the Illumina HiSeq 2500 platform.

Results

The number of operational taxonomic units (OTUs) showed a decrease in the diversity of gut microbiota with increasing body weight. The alpha diversity indices showed that the normal weight group had higher abundance and observed species than the obese group (Chao1: P < 0.001; observed species: P < 0.001; PD whole tree: P < 0.001; Shannon index: P = 0.008). Principal coordinate analysis (PCoA) and Nonmetric multidimensional scaling (NMDS) revealed significant differences in gut microbial community structure between the normal weight group and the obese group. The liner discriminant analysis (LDA) effect size (LEfSe) analysis showed that fifty-five species of bacteria were abundant in the fecal samples of the normal weight group and forty-five species of bacteria were abundant in the obese group. In regard to phyla, the gut microbiota in the obese group had lower proportions of Bacteroidetes (51.35%) compared to the normal weight group (55.48%) (P = 0.030). There was no statistical difference in Firmicutes between the two groups (P = 0.436), and the Firmicutes/Bacteroidetes between the two groups had no statistical difference (P = 0.983). At the genus level, Faecalibacterium, Phascolarctobacterium, Lachnospira, Megamonas, and Haemophilus were significantly more abundant in the obese group than in the normal weight group (P = 0.048, P = 0.018, P < 0.001, P = 0.040, and P = 0.003, respectively). The fecal microbiota of children in the obese group had lower proportions of Oscillospira and Dialister compared to the normal weight group (P = 0.002 and P = 0.002, respectively).

Conclusions

Our results showed a decrease in gut microbiota abundance and diversity as the BMI increased. Variations in the bacterial community structure were associated with obesity. Gut microbiota dysbiosis might play a crucial part in the development of obesity in Chinese children.

Unsaturated alginate oligosaccharides attenuated obesity-related metabolic abnormalities by modulating gut microbiota in high-fat-diet mice

A new potent prebiotic oligosaccharide for obesity and related metabolic abnormalities by modulating gut microbiota.

Gastrointestinal Helminth Infection Improves Insulin Sensitivity, Decreases Systemic Inflammation, and Alters the Composition of Gut Microbiota in Distinct Mouse Models of Type 2 Diabetes

Type 2 diabetes (T2D) is a major health problem and is considered one of the top 10 diseases leading to death globally. T2D has been widely associated with systemic and local inflammatory responses and with alterations in the gut microbiota. Microorganisms, including parasitic worms and gut microbes have exquisitely co-evolved with their hosts to establish an immunological interaction that is essential for the formation and maintenance of a balanced immune system, including suppression of excessive inflammation. Herein we show that both prophylactic and therapeutic infection of mice with the parasitic hookworm-like nematode, Nippostrongylus brasiliensis, significantly reduced fasting blood glucose, oral glucose tolerance and body weight gain in two different diet-induced mouse models of T2D. Helminth infection was associated with elevated type 2 immune responses including increased eosinophil numbers in the mesenteric lymph nodes, liver and adipose tissues, as well as increased expression of IL-4 and alternatively activated macrophage marker genes in adipose tissue, liver and gut. N. brasiliensis infection was also associated with significant compositional changes in the gut microbiota at both the phylum and order levels. Our findings show that N. brasiliensis infection drives changes in local and systemic immune cell populations, and that these changes are associated with a reduction in systemic and local inflammation and compositional changes in the gut microbiota which cumulatively might be responsible for the improved insulin sensitivity observed in infected mice. Our findings indicate that carefully controlled therapeutic hookworm infection in humans could be a novel approach for treating metabolic syndrome and thereby preventing T2D.

Impact of Glucoraphanin-Mediated Activation of Nrf2 on Non-Alcoholic Fatty Liver Disease with a Focus on Mitochondrial Dysfunction

Non-alcoholic fatty liver disease (NAFLD) is a common disease in Western nations and ranges in severity from steatosis to steatohepatitis (NASH). NAFLD is a genetic-environmental-metabolic stress-related disease of unclear pathogenesis. NAFLD is triggered by caloric overconsumption and physical inactivity, which lead to insulin resistance and oxidative stress. A growing body of evidence indicates that mitochondrial dysfunction plays a critical role in the pathogenesis of NAFLD. Mitochondrial dysfunction not only promotes fat accumulation, but also leads to generation of reactive oxygen species (ROS) and lipid peroxidation, resulting in oxidative stress in hepatocytes. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important modulator of antioxidant signaling that serves as a primary cellular defense against the cytotoxic effects of oxidative stress. The pharmacological induction of Nrf2 ameliorates obesity-associated insulin resistance and NAFLD in a mouse model. Sulforaphane and its precursor glucoraphanin are derived from broccoli sprouts and are the most potent natural Nrf2 inducers—they may protect mitochondrial function, thus suppressing the development of NASH. In this review, we briefly describe the role of mitochondrial dysfunction in the pathogenesis of NASH and the effects of glucoraphanin on its development.

[Intestinal microbiota and allogeneic stem cell transplantation]

Allogeneic hematopoïetic stem cell transplantation is one of the most efficient curative treatment for acute leukemia. But it is also a heavy process with an important risk of complications, particularly infection and graft versus host disease. Increasing data in literature show that an alteration of the intestinal microbiota of allogeneic stem cell recipients is associated with these complications. Indeed, treatments used during conditioning regimen lead to an impaired microbiota, which cannot fulfill its protective functions anymore. To limit this microbiota impairment, we could restore a healthy microbiota by a fecal microbiota transplantation, which has already shown its efficiency in the treatment of Clostridium difficile infection. The aim of this review is to describe the intestinal microbiota, the link between microbiota and complications of allogeneic stem cells transplantation, and the recent published data on fecal microbiota transplantation in this field.

Isolation and Identification of Lactic Acid Bacteria Probiotic Culture Candidates for the Treatment of Salmonella enterica Serovar Enteritidis in Neonatal Turkey Poults

The effect of Lactobacillus spp.-based probiotic candidates on Salmonella enterica serovar Enteritidis (SE) colonization was evaluated in two separate experiments. In each experiment, sixty-one day-of-hatch female turkey poults were obtained from a local hatchery. In both experiments, poults were challenged via oral gavage with 10⁴ cfu/poult of SE and randomly allocated to one of two groups (n = 30 poults): (1) the positive control group and (2) the probiotic treated group. Heated brooder batteries were used for housing each group separately and poults were allowed ad libitum access to water and unmedicated turkey starter feed. 1 h following the SE challenge, poults were treated with 10⁶ cfu/poult of probiotic culture via oral gavage or phosphate-buffered saline （PBS）to control groups. A total of 24 h post-treatment, poults were euthanized and the ceca and cecal tonsils from twenty poults were collected aseptically for SE recovery. In both trials, a significant reduction in the incidence and log₁₀ cfu/g of SE were observed in poults treated with the probiotic when compared with control poults (p ≤ 0.05). The results of the present study suggest that the administration of this lactic acid-producing bacteria (LAB)-based probiotic 1 h after an SE challenge can be useful in reducing the cecal colonization of this pathogen in neonatal poults.

Intestinal permeability in the pathogenesis of liver damage: From non-alcoholic fatty liver disease to liver transplantation

The intimate connection and the strict mutual cooperation between the gut and the liver realizes a functional entity called gut-liver axis. The integrity of intestinal barrier is crucial for the maintenance of liver homeostasis. In this mutual relationship, the liver acts as a second firewall towards potentially harmful substances translocated from the gut, and is, in turn, is implicated in the regulation of the barrier. Increasing evidence has highlighted the relevance of increased intestinal permeability and consequent bacterial translocation in the development of liver damage. In particular, in patients with non-alcoholic fatty liver disease recent hypotheses are considering intestinal permeability impairment, diet and gut dysbiosis as the primary pathogenic trigger. In advanced liver disease, intestinal permeability is enhanced by portal hypertension. The clinical consequence is an increased bacterial translocation that further worsens liver damage. Furthermore, this pathogenic mechanism is implicated in most of liver cirrhosis complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma. After liver transplantation, the decrease in portal pressure should determine beneficial effects on the gut-liver axis, although are incompletely understood data on the modifications of the intestinal permeability and gut microbiota composition are still lacking. How the modulation of the intestinal permeability could prevent the initiation and progression of liver disease is still an uncovered area, which deserves further attention.

Targeting ROS and cPLA2/COX2 Expressions Ameliorated Renal Damage in Obese Mice with Endotoxemia

Obesity is associated with metabolic endotoxemia, reactive oxygen species (ROS), chronic inflammation, and obese kidney fibrosis. Although the fat-intestine-kidney axis has been documented, the pathomechanism and therapeutic targets of obese kidney fibrosis remain unelucidated. To mimic obese humans with metabolic endotoxemia, high-fat-diet-fed mice (HF group) were injected with lipopolysaccharide (LPS) to yield the obese kidney fibrosis-metabolic endotoxemia mouse model (HL group). Therapeutic effects of ROS, cytosolic phospholipases A2 (cPLA2) and cyclooxygenase-2 (COX-2) inhibitors were analyzed with a quantitative comparison of immunohistochemistry stains and morphometric approach in the tubulointerstitium of different groups. Compared with basal and HF groups, the HL group exhibited the most prominent obese kidney fibrosis, tubular epithelial lipid vacuoles, and lymphocyte infiltration in the tubulointerstitium. Furthermore, inhibitors of nonspecific ROS, cPLA2 and COX-2 ameliorated the above renal damages. Notably, the ROS-inhibitor-treated group ameliorated not only oxidative injury but also the expression of cPLA2 and COX-2, indicating that ROS functions as the upstream signaling molecule in the inflammatory cascade of obese kidney fibrosis. ROS acts as a key messenger in the signaling transduction of obese kidney fibrosis, activating downstream cPLA2 and COX-2. The given antioxidant treatment ameliorates obese kidney fibrosis resulting from a combined high-fat diet and LPS-ROS could serve as a potential therapeutic target of obese kidney fibrosis with metabolic endotoxemia.

Associations of the Fecal Microbial Proteome Composition and Proneness to Diet-induced Obesity

Consumption of refined high-fat, low-fiber diets promotes development of obesity and its associated consequences. Although genetics play an important role in dictating susceptibility to such obesogenic diets, mice with nearly uniform genetics exhibit marked heterogeneity in their extent of obesity in response to such diets. This suggests non-genetic determinants play a role in diet-induced obesity. Hence, we sought to identify parameters that predict, and/or correlate with, development of obesity in response to an obesogenic diet. We assayed behavior, metabolic parameters, inflammatory markers/cytokines, microbiota composition, and the fecal metaproteome, in a cohort of mice (n = 50) prior to, and the 8 weeks following, administration of an obesogenic high-fat low-fiber diet. Neither behavioral testing nor quantitation of inflammatory markers broadly predicted severity of diet-induced obesity. Although, the small subset of mice that exhibited basal elevations in serum IL-6 (n = 5) were among the more obese mice in the cohort. While fecal microbiota composition changed markedly in response to the obesogenic diet, it lacked the ability to predict which mice were relative prone or resistant to obesity. In contrast, fecal metaproteome analysis revealed functional and taxonomic differences among the proteins associated with proneness to obesity. Targeted interrogation of microbiota composition data successfully validated the taxonomic differences seen in the metaproteome. Although future work will be needed to determine the breadth of applicability of these associations to other cohorts of animals and humans, this study nonetheless highlights the potential power of gut microbial proteins to predict and perhaps impact development of obesity.

Understanding the Role of the Gut Microbiome and Microbial Metabolites in Obesity and Obesity-Associated Metabolic Disorders: Current Evidence and Perspectives

PURPOSE

In this review, we summarize current evidence on the gut microbiome and microbial metabolites in relation to obesity and obesity-associated metabolic disorders. Special emphasis is given on mechanisms interconnecting gut microbiome and microbial metabolites with metabolic disorders as well as on potential preventive and therapeutic perspectives with a "bench to bedside" approach.

RECENT FINDINGS

Recent data have highlighted the role of gut dysbiosis in the etiology and pathogenesis of metabolic disorders, including obesity, metabolic syndrome, type 2 diabetes mellitus, and non-alcoholic fatty liver disease. Overall, most studies have demonstrated a reduction in gut microbiome diversity and richness in obese subjects, but there is still much debate on the exact microbial signature of a healthy or an obese gut microbiome. Despite the controversial role of an altered gut microbiome as a cause or consequence of obesity in human studies, numerous animal studies and certain human studies suggest beneficial metabolic effects of certain microbial intestinal metabolites, such as butyrate, that could be used in the prevention and treatment of obesity and its comorbidities. More randomized controlled trials and larger prospective studies including well-defined cohorts as well as a multi-omics approach are warranted to better identify the associations between the gut microbiome, microbial metabolites, and obesity and its metabolic complications.

Relationship(s) between obesity and inflammatory bowel diseases: possible intertwined pathogenic mechanisms

The inflammatory bowel diseases, Crohn's and ulcerative colitis have increased in incidence and prevalence from the mid-eighteen to the late nineteen centuries. From then to the current twenty-first century there has been a more rapid expansion of these disease to areas previously experiencing low rates. This latter expansion coincides with the current obesity pandemic which also began toward the end of the last century. Although the two diseases have radically different frequencies, there are interesting links between them. Four areas link the diseases. On an epidemiological level, IBD tends to follow a north-south gradient raising the importance of vitamin D in protection. Obesity has very weak relationship with latitude, but both diseases follow adult lactase distributions colliding in this plane. Is it possible that obesity (a low vitamin D condition with questionable response to supplements) reduces effects in IBD? On a pathogenic level, pro-inflammatory processes mark both IBD and obesity. The similarity raises the question of whether obesity could facilitate the development of IBD. Features of the metabolic syndrome occur in both, with or without obesity in IBD. The fourth interaction between the two diseases is the apparent effect of obesity on the course of IBD. There are suggestions that obesity may reduce the efficacy of biologic agents. Yet there is some suggestion also that obesity may reduce the need for hospitalization and surgery. The apparent co-expansion of both obesity and IBD suggests similar environmental changes may be involved in the promotion of both.

Antibiotic use in early childhood and risk of obesity: longitudinal analysis of a national cohort

BACKGROUND

Taking oral antibiotics during childhood has been linked with an increased risk of childhood obesity. This study assessed any potential association in number of courses of antibiotics taken between 2-3 and 4-5 years of age and body mass trajectory up to age 5.

METHODS

The study was a secondary analysis of 8186 children and their parents from the infant cohort of the Irish National Longitudinal Study of Children. Antibiotic use was measured by parental recall between ages 2-3 and 4-5. Longitudinal models described the relationship between antibiotic exposure and body mass index (BMI) standard deviation scores and binary outcomes, and examined interactions between covariates, which included socioeconomic status, diet assessed by food frequency questionnaires and maternal BMI.

RESULTS

Any antibiotic usage between 2 and 3 years did not predict risk of overweight or obesity at age 5. Four or more courses of antibiotics between 2 and 3 years were independently associated with obesity at age 5 (odds ratio 1.6, 95% confidence interval 1.11-2.31). Effect size was modest (coefficient + 0.09 body mass SD units, standard error 0.04, P = 0.037). Maternal BMI modified the relationship: ≥ 4 courses of antibiotics between 2 and 3 years were associated with a + 0.12 body mass SD units increase in weight at age 5 among children of normal-weight mothers (P = 0.035), but not in children of overweight mothers.

CONCLUSIONS

Number of antibiotic courses, rather than antibiotic use, may be an important factor in any link between early antibiotic exposure and subsequent childhood obesity. Research is needed to confirm differential effects on babies of normal versus overweight/obese mothers independent of socioeconomic factors.