The gut microbiome of Mexican children affected by obesity

Multivariate Analysis and Correlation Study Shows the Impact of Anthropometric and Demographic Variables on Gut Microbiota in Obese Egyptian Children

Deciphering the gut microbiome's link to obesity is crucial. Our study characterized the gut microbial community in Egyptian children and investigated the effect of covariates on the gut microbiome, body mass index (BMI), geographical location, gender, and age. We used 16S rRNA sequencing to characterize the gut microbial communities of 49 children. We then evaluated these communities for diversity, potential biomarkers, and functional capacity. Alpha diversity of the non-obese group was higher than that of the obese group (Chao1, P = 0.006 and observed species, P = 0.003). Beta diversity analysis revealed significant variations in the gut microbiome between the two geographical locations, Cairo and Ismailia (unweighted UniFrac, P = 0.03) and between obesity statuses, obese and non-obese (weighted UniFrac, P = 0.034; unweighted UniFrac, P = 0.015). We observed a significantly higher Firmicutes/Bacteroidetes ratio in obese males than in non-obese males (P = 0.004). Interestingly, this difference was not seen in females (P = 0.77). Multivariable association with linear models (MaAsLin2) identified 8 microbial features associated with obesity, 12 associated with non-obesity, and found 29 and 13 features specific to Cairo and Ismailia patients, respectively. It has also shown one microbial feature associated with patients under five years old. MaAsLin2, however, failed to recognize any association between gender and the gut microbiome. Moreover, it could find the most predominant features in groups 2-9 but not in group 1. Another method used in the analysis is the Linear discriminant analysis Effect Size (LEfSe) approach, which effectively identified 19 biomarkers linked to obesity, 9 linked non-obesity, 20 linked to patients residing in Cairo, 14 linked to patients in Ismailia, one linked to males, and 12 linked to females. LEfSe could not, however, detect any prevalent bacteria among children younger or older than five. Future studies should take advantage of such correlations, specifically BMI, to determine the interventions needed for obesity management.

Comparing massa medicata fermentata before and after charred in terms of digestive promoting effect via metabolomics and microbiome analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Massa Medicata Fermentata, a fermented Chinese medicine, is produced by the fermentation of six traditional Chinese medicines. Liu Shenqu (LSQ) and charred Liu Shenqu (CLSQ) have been used for strengthening the spleen and enhancing digestion for over a thousand years, and CLSQ is commonly used in clinical practice. However, it is unclear whether there is a difference in the spleen strengthening and digestion effects between LSQ and CLSQ, as well as their mechanisms of action.

AIM OF STUDY

This study aims to compare the effects of LSQ and CLSQ on the digestive function of functional dyspepsia (FD) rats and reveal their mechanisms of action.

MATERIALS AND METHODS

SPF grade SD rats were randomly divided into 6 groups: control group, model group, Liu Shenqu decoction low-dosage (LSQ LD) group, Liu Shenqu decoction high-dosage (LSQ HD) group, charred Liu Shenqu decoction low-dosage (CLSQ LD) group, and charred Liu Shenqu decoction high-dosage (CLSQ HD) group. Rats were injected intraperitoneally with reserpine to create an FD model and then treated by intragastric administration. During this period, record the weight and food intake of the animals. After 18 days of treatment, specimens of the gastric antrum, spleen, and duodenum of rats were taken for pathological staining and immunohistochemical detection of Ghrelin protein expression. Enzyme linked immunosorbent assay (ELISA) was used to determine the concentration of relevant gastrointestinal hormones in serum. The 16 S rDNA sequencing method was used to evaluate the effect of cecal contents on the structure of the gut microbiota in experimental rats. Plasma metabolomics analysis was performed using ultra high performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC-QTOF-MS) to further reveal their mechanism of action.

RESULTS

LSQ and CLSQ improved the pathological tissue histological structure of FD rats and increased the levels of MTL and GAS hormones in serum and the levels of ghrelin in the gastric antrum, spleen, and duodenum, while reducing VIP, CCK, and SP hormone levels. The above results showed that the therapeutic efficacy of CLSQ is better than that of LSQ. Futhermore, the mechanism of action of LSQ and CLSQ were revealed. The 16 S rDNA sequencing results showed that both LSQ and CLSQ can improve the composition and diversity of the gut microbiota. And metabolomic analysis demonstrated that 20 metabolites changed after LSQ treatment, and 16 metabolites underwent continuous changes after CLSQ treatment. Further analysis revealed that LSQ mainly intervened in the metabolic pathways of glycerol phospholipid metabolism and arginine and proline metabolism, but CLSQ mainly intervened in the metabolic pathways of ether lipid metabolism, sphingolipid metabolism, and glycerophospholipid metabolism.

CONCLUSIONS

Both LSQ and CLSQ can improve functional dyspepsia in FD rats, but CLSQ has a stronger improvement effect on FD. Although their mechanisms of action are all related to regulating gastrointestinal hormone secretion, significantly improving intestinal microbiota disorders, and improving multiple metabolic pathways, but the specific gut microbiota and metabolic pathways they regulate are different.

Inhibitory Effects of Soluble Dietary Fiber from Foxtail Millet on Colorectal Cancer by the Restoration of Gut Microbiota

Colorectal cancer (CRC) is a common malignant tumor that occurs in the colon. Gut microbiota is a complex ecosystem that plays an important role in the pathogenesis of CRC. Our previous studies showed that the soluble dietary fiber of foxtail millet (FMB-SDF) exhibited significant antitumor activity in vitro. The present study evaluated the anticancer potential of FMB-SDF in the azoxymethane (AOM)- and dextran sodium sulfate (DSS)-induced mouse CRC models. The results showed that FMB-SDF could significantly alleviate colon cancer symptoms in mice. Further, we found that FMB-SDF consumption significantly altered gut microbiota diversity and the overall structure and regulated the abundance of some microorganisms in CRC mice. Meanwhile, KEGG pathway enrichment showed that FMB-SDF can also alleviate the occurrence of colon cancer in mice by regulating certain cancer-related signaling pathways. In conclusion, our findings may provide a novel approach for the prevention and biotherapy of CRC.

Fucoxanthin extract ameliorates obesity associated with modulation of bile acid metabolism and gut microbiota in high-fat-diet fed mice

PURPOSE

Fucoxanthin extract (FX) is a type of carotenoid with a beneficial effect against obesity. The purpose of this study was to explore its precise action mechanism of losing weight.

METHODS

A high-fat diet induced obesity mouse model was established to study the effects of different doses of FX on C57BL/6J male mice for 12 weeks. Following intervention, serum indices, tissue sections, liver gene expression, and intestinal microorganisms were analyzed.

RESULTS

FX at low, medium, and high dosages (80, 160, and 320 mg/kg/day, respectively) for 12 weeks was associated with the lower body weight of mice when compared to that of high-fat-diet fed mice. It also improved glucose tolerance as well as serum lipid levels, and reduced fat accumulation. Significant regulation of bile acid metabolism and intestinal microbiota may contribute to the above effects. The bile acids in the FXH group were significantly increased. A low-dose and a medium-dose FX increased the level of transmembrane G protein-coupled receptor 5 (TGR5); a low-dose and high-dose FX increased the farnesoid X receptor (FXR) expression, and a medium-dose had no effect. 16S rRNA sequencing indicated that the Lachnospiraceae and Oscillospiraceae contributed to the beneficial effects of FX.

CONCLUSION

Our study sheds light on mechanisms behind the weight-lowering of FX, and manifested that bile acid metabolism and gut microbiota may be potential therapies. These results support that FX is a valuable candidate for promoting health and alleviating obesity.

Curcumin Mitigates the High-Fat High-Sugar Diet-Induced Impairment of Spatial Memory, Hepatic Metabolism, and the Alteration of the Gut Microbiome in Alzheimer's Disease-Induced (3xTg-AD) Mice

The escalating prevalence of metabolic diseases and an aging demographic has been correlated with a concerning rise in Alzheimer's disease (AD) incidence. This study aimed to access the protective effects of curcumin, a bioactive flavonoid from turmeric, on spatial memory, metabolic functions, and the regulation of the gut microbiome in AD-induced (3xTg-AD) mice fed with either a normal chow diet (NCD) or a high-fat high-sugar diet (HFHSD). Our findings revealed an augmented susceptibility of the HFHSD-fed 3xTg-AD mice for weight gain and memory impairment, while curcumin supplementation demonstrated a protective effect against these changes. This was evidenced by significantly reduced body weight gain and improved behavioral and cognitive function in the curcumin-treated group. These improvements were substantiated by diminished fatty acid synthesis, altered cholesterol metabolism, and suppressed adipogenesis-related pathways in the liver, along with modified synaptic plasticity-related pathways in the brain. Moreover, curcumin enriched beneficial gut microbiota, including Oscillospiraceae and Rikenellaceae at the family level, and Oscillibacter, Alistipes, Pseudoflavonifractor, Duncaniella, and Flintibacter at the genus level. The observed alteration in these gut microbiota profiles suggests a potential crosswalk in the liver and brain for regulating metabolic and cognitive functions, particularly in the context of obesity-associated cognitive disfunction, notably AD.

Gut microbes in metabolic disturbances. Promising role for therapeutic manipulations?

The prevalence of overweight, obesity, type 2 diabetes, metabolic syndrome and steatotic liver disease is rapidly increasing worldwide with a huge economic burden in terms of morbidity and mortality. Several genetic and environmental factors are involved in the onset and development of metabolic disorders and related complications. A critical role also exists for the gut microbiota, a complex polymicrobial ecology at the interface of the internal and external environment. The gut microbiota contributes to food digestion and transformation, caloric intake, and immune response of the host, keeping the homeostatic control in health. Mechanisms of disease include enhanced energy extraction from the non-digestible dietary carbohydrates, increased gut permeability and translocation of bacterial metabolites which activate a chronic low-grade systemic inflammation and insulin resistance, as precursors of tangible metabolic disorders involving glucose and lipid homeostasis. The ultimate causative role of gut microbiota in this respect remains to be elucidated, as well as the therapeutic value of manipulating the gut microbiota by diet, pre- and pro- synbiotics, or fecal microbial transplantation.

Metagenomic analysis reveals distinct changes in the gut microbiome of obese Chinese children

BACKGROUND

The prevalence of obese children in China is increasing, which poses a great challenge to public health. Gut microbes play an important role in human gut health, and changes in gut status are closely related to obesity. However, how gut microbes contribute to obesity in children remains unclear. In our study, we performed shotgun metagenomic sequencing of feces from 23 obese children, 8 overweight children and 22 control children in Chengdu, Sichuan, China.

RESULTS

We observed a distinct difference in the gut microbiome of obese children and that of controls. Compared with the controls, bacterial pathogen Campylobacter rectus was significantly more abundant in obese children. In addition, functional annotation of microbial genes revealed that there might be gut inflammation in obese children. The guts of overweight children might belong to the transition state between obese and control children due to a gradient in relative abundance of differentially abundant species. Finally, we compared the gut metagenomes of obese Chinese children and obese Mexican children and found that Trichuris trichiura was significantly more abundant in the guts of obese Mexican children.

CONCLUSIONS

Our results contribute to understanding the changes in the species and function of intestinal microbes in obese Chinese children.

Maternal Consumption of Non-Nutritive Sweeteners during Pregnancy Is Associated with Alterations in the Colostrum Microbiota

Non-nutritive sweeteners (NNSs) provide a sweet taste to foods and beverages without significantly adding calories. Still, their consumption has been linked to modifications in adult's and children's gut microbiota and the disruption of blood glucose control. Human milk microbiota are paramount in establishing infants' gut microbiota, but very little is known about whether the consumption of sweeteners can alter it. To address this question, we sequenced DNA extracted colostrum samples from a group of mothers, who had different levels of NNS consumption, using the Ion Torrent Platform. Our results show that the "core" of colostrum microbiota, composed of the genera Bifidobacterium, Blautia, Cutibacteium, Staphylococcus, and Streptococcus, remains practically unchanged with the consumption of NNS during pregnancy, but specific genera display significant alterations, such as Staphylococcus and Streptococcus. A significant increase in the unclassified archaea Methanobrevibacter spp. was observed as the consumption frequency of NNS increased. The increase in the abundance of this archaea has been previously linked to obesity in Mexican children. NNS consumption during pregnancy could be related to changes in colostrum microbiota and may affect infants' gut microbiota seeding and their future health.

Effects of Synbiotic Supplementation on Metabolic Syndrome Traits and Gut Microbial Profile among Overweight and Obese Hong Kong Chinese Individuals: A Randomized Trial

In view of the limited evidence showing anti-obesity effects of synbiotics via modulation of the gut microbiota in humans, a randomized clinical trial was performed. Assessment of the metabolic syndrome traits and profiling of the fecal gut microbiota using 16S rRNA gene sequencing in overweight and obese Hong Kong Chinese individuals before and after dietary intervention with an 8-week increased consumption of fruits and vegetables and/or synbiotic supplementation was conducted. The selected synbiotic contained two probiotics (Lactobacillus acidophilus NCFM and Bifidobacterium lactis HN019) and a prebiotic (polydextrose). Fifty-five overweight or obese individuals were randomized and divided into a synbiotic group (SG; n = 19), a dietary intervention group (DG; n = 18), and a group receiving combined interventions (DSG; n = 18). DSG showed the greatest weight loss effects and number of significant differences in clinical parameters compared to its baseline values-notably, decreases in fasting glucose, insulin, HOMA-IR, and triglycerides and an increase in HDL-cholesterol. DSG lowered Megamonas abundance, which was positively associated with BMI, body fat mass, and trunk fat mass. The results suggested that increasing dietary fiber consumption from fruits and vegetables combined with synbiotic supplementation is more effective than either approach alone in tackling obesity.

From-Toilet-to-Freezer: A Review on Requirements for an Automatic Protocol to Collect and Store Human Fecal Samples for Research Purposes

The composition, viability and metabolic functionality of intestinal microbiota play an important role in human health and disease. Studies on intestinal microbiota are often based on fecal samples, because these can be sampled in a non-invasive way, although procedures for sampling, processing and storage vary. This review presents factors to consider when developing an automated protocol for sampling, processing and storing fecal samples: donor inclusion criteria, urine-feces separation in smart toilets, homogenization, aliquoting, usage or type of buffer to dissolve and store fecal material, temperature and time for processing and storage and quality control. The lack of standardization and low-throughput of state-of-the-art fecal collection procedures promote a more automated protocol. Based on this review, an automated protocol is proposed. Fecal samples should be collected and immediately processed under anaerobic conditions at either room temperature (RT) for a maximum of 4 h or at 4 °C for no more than 24 h. Upon homogenization, preferably in the absence of added solvent to allow addition of a buffer of choice at a later stage, aliquots obtained should be stored at either -20 °C for up to a few months or -80 °C for a longer period-up to 2 years. Protocols for quality control should characterize microbial composition and viability as well as metabolic functionality.

Phage-microbe dynamics after sterile faecal filtrate transplantation in individuals with metabolic syndrome: a double-blind, randomised, placebo-controlled clinical trial assessing efficacy and safety

Bacteriophages (phages) are bacterial viruses that have been shown to shape microbial communities. Previous studies have shown that faecal virome transplantation can decrease weight gain and normalize blood glucose tolerance in diet-induced obese mice. Therefore, we performed a double-blind, randomised, placebo-controlled pilot study in which 24 individuals with metabolic syndrome were randomised to a faecal filtrate transplantation (FFT) from a lean healthy donor (n = 12) or placebo (n = 12). The primary outcome, change in glucose metabolism, and secondary outcomes, safety and longitudinal changes within the intestinal bacteriome and phageome, were assessed from baseline up to 28 days. All 24 included subjects completed the study and are included in the analyses. While the overall changes in glucose metabolism are not significantly different between both groups, the FFT is well-tolerated and without any serious adverse events. The phage virion composition is significantly altered two days after FFT as compared to placebo, which coincides with more virulent phage-microbe interactions. In conclusion, we provide evidence that gut phages can be safely administered to transiently alter the gut microbiota of recipients.

The evolving role of methanogenic archaea in mammalian microbiomes

Methanogenic archaea (methanogens) represent a diverse group of microorganisms that inhabit various environmental and host-associated microbiomes. These organisms play an essential role in global carbon cycling given their ability to produce methane, a potent greenhouse gas, as a by-product of their energy production. Recent advances in culture-independent and -dependent studies have highlighted an increased prevalence of methanogens in the host-associated microbiome of diverse animal species. Moreover, there is increasing evidence that methanogens, and/or the methane they produce, may play a substantial role in human health and disease. This review addresses the expanding host-range and the emerging view of host-specific adaptations in methanogen biology and ecology, and the implications for host health and disease.

Distinct fecal microbial signatures are linked to sex and chronic immune activation in pediatric HIV infection

Introduction

Our understanding of HIV-associated gut microbial dysbiosis in children perinatally-infected with HIV (CLWH) lags behind that of adults living with HIV. Childhood represents a critical window for the gut microbiota. Any disturbances, including prolonged exposure to HIV, antiretroviral drugs, and antibiotics are likely to have a significant impact on long-term health, resulting in a less resilient gut microbiome. The objective of our study was to characterize the gut microbiota in CLWH, and compare it with HIV-unexposed and -uninfected children.

Methods

We enrolled 31 children aged 3 to 15 years; 15 were CLWH and 16 were HUU. We assessed dietary patterns and quality; quantified soluble and cellular markers of HIV disease progression by flow cytometry, enzyme-linked immunosorbent and multiplex-bead assays, and profiled the gut microbiota by 16S rRNA sequencing. We explored relationships between the gut microbiota, antibiotic exposure, dietary habits, soluble and cellular markers and host metadata.

Results

Children had a Western-type diet, their median health eating index score was 67.06 (interquartile range 58.76-74.66). We found no discernable impact of HIV on the gut microbiota. Alpha diversity metrics did not differ between CLWH and HUU. Sex impacted the gut microbiota (R-squared= 0.052, PERMANOVA p=0.024). Male children had higher microbial richness compared with female children. Two taxa were found to discriminate female from male children independently from HIV status: Firmicutes for males, and Bacteroides for females. Markers of HIV disease progression were comparable between CLWH and HUU, except for the frequency of exhausted CD4+ T cells (PD-1+) which was increased in CLWH (p=0.0024 after adjusting for confounders). Both the frequency of exhausted CD4+ and activated CD4+ T cells (CD38+ HLADR+) correlated positively with the relative abundance of Proteobacteria (rho=0.568. false discovery rate (FDR)-adjusted p= 0.029, and rho=0.62, FDR-adjusted p=0.0126, respectively).

Conclusion

The gut microbiota of CLWH appears similar to that of HUU, and most markers of HIV disease progression are normalized with long-term ART, suggesting a beneficial effect of the latter on the gut microbial ecology. The relationship between exhausted and activated CD4+ T cells and Proteobacteria suggests a connection between the gut microbiome, and premature aging in CLWH.

Salivary microbiome and hypertension in the Qatari population

BACKGROUND

The prevalence of hypertension in Qatar is 33 percent of the adult population. It is postulated that the salivary microbiome can regulate blood pressure (BP). However, limited investigations exist to prove this hypothesis. Therefore, we examined the difference in the salivary microbiome composition between hypertensive and normotensive Qatari subjects.

METHODS

A total of 1190 Qatar Genome Project (QGP) participants (Mean age = 43 years) were included in this study. BP for all participants was classified into Normal (n = 357), Stage1 (n = 336), and Stage2: (n = 161) according to the American Heart Association guidelines. 16S-rRNA libraries were sequenced and analyzed using QIIME-pipeline, and PICRUST was used to predict functional metabolic routes. Machine Learning (ML) strategies were applied to identify salivary microbiome-based predictors of hypertension.

RESULTS

Differential abundant analysis (DAA) revealed that Bacteroides and Atopobium were the significant members of the hypertensive groups. Alpha and beta diversity indices indicated dysbiosis between the normotensive and hypertensive groups. ML-based prediction models revealed that these markers could predict hypertension with an AUC (Area under the curve) of 0.89. Functional predictive analysis disclosed that Cysteine and Methionine metabolism and the sulphur metabolic pathways involving the renin-angiotensin system were significantly higher in the normotensive group. Therefore, members of Bacteroides and Atopobium can serve as predictors of hypertension. Likewise, Prevotella, Neisseria, and Haemophilus can be the protectors that regulate BP via nitric acid synthesis and regulation of the renin-angiotensin system.

CONCLUSION

It is one of the first studies to assess salivary microbiome and hypertension as disease models in a large cohort of the Qatari population. Further research is needed to confirm these findings and validate the mechanisms involved.

Gut microbial composition and functionality of school-age Mexican population with metabolic syndrome and type-2 diabetes mellitus using shotgun metagenomic sequencing

Gut metagenome in pediatric subjects with metabolic syndrome (MetS) and type-2 diabetes mellitus (T2DM) has been poorly studied, despite an alarming worldwide increase in the prevalence and incidence of obesity and MetS within this population. The objective of this study was to characterize the gut microbiome taxonomic composition of Mexican pediatric subjects with MetS and T2DM using shotgun metagenomics and analyze the potential relationship with metabolic changes and proinflammatory effects. Paired-end reads of fecal DNA samples were obtained through the Illumina HiSeq X Platform. Statistical analyses and correlational studies were conducted using gut microbiome data and metadata from all individuals. Gut microbial dysbiosis was observed in MetS and T2DM children compared to healthy subjects, which was characterized by an increase in facultative anaerobes (i.e., enteric and lactic acid bacteria) and a decrease in strict anaerobes (i.e., Erysipelatoclostridium, Shaalia, and Actinomyces genera). This may cause a loss of gut hypoxic environment, increased gut microbial nitrogen metabolism, and higher production of pathogen-associated molecular patterns. These metabolic changes may trigger the activation of proinflammatory activity and impair the host's intermediate metabolism, leading to a possible progression of the characteristic risk factors of MetS and T2DM, such as insulin resistance, dyslipidemia, and an increased abdominal circumference. Furthermore, specific viruses (Jiaodavirus genus and Inoviridae family) showed positive correlations with proinflammatory cytokines involved in these metabolic diseases. This study provides novel evidence for the characterization of MetS and T2DM pediatric subjects in which the whole gut microbial composition has been characterized. Additionally, it describes specific gut microorganisms with functional changes that may influence the onset of relevant health risk factors.

Characterization of gut microbiota associated with metabolic syndrome and type-2 diabetes mellitus in Mexican pediatric subjects

BACKGROUND

Childhood obesity is a serious public health concern that confers a greater risk of developing important comorbidities such as MetS and T2DM. Recent studies evidence that gut microbiota may be a contributing factor; however, only few studies exist in school-age children. Understanding the potential role of gut microbiota in MetS and T2DM pathophysiology from early stages of life might contribute to innovative gut microbiome-based interventions that may improve public health. The main objective of the present study was to characterize and compare gut bacteria of T2DM and MetS children against control subjects and determine which microorganisms might be potentially related with cardiometabolic risk factors to propose gut microbial biomarkers that characterize these conditions for future development of pre-diagnostic tools.

RESULTS

Stool samples from 21 children with T2DM, 25 with MetS, and 20 controls (n = 66) were collected and processed to conduct 16S rDNA gene sequencing. α- and β-diversity were studied to detect microbial differences among studied groups. Spearman correlation was used to analyze possible associations between gut microbiota and cardiometabolic risk factors, and linear discriminant analyses (LDA) were conducted to determine potential gut bacterial biomarkers. T2DM and MetS showed significant changes in their gut microbiota at genus and family level. Read relative abundance of Faecalibacterium and Oscillospora was significantly higher in MetS and an increasing trend of Prevotella and Dorea was observed from the control group towards T2DM. Positive correlations were found between Prevotella, Dorea, Faecalibacterium, and Lactobacillus with hypertension, abdominal obesity, high glucose levels, and high triglyceride levels. LDA demonstrated the relevance of studying least abundant microbial communities to find specific microbial communities that were characteristic of each studied health condition.

CONCLUSIONS

Gut microbiota was different at family and genus taxonomic levels among controls, MetS, and T2DM study groups within children from 7 to 17 years old, and some communities seemed to be correlated with relevant subjects' metadata. LDA helped to find potential microbial biomarkers, providing new insights regarding pediatric gut microbiota and its possible use in the future development of gut microbiome-based predictive algorithms.

Soluble, Diferuloylated Corn Bran Glucuronoarabinoxylans Modulate the Human Gut Microbiota In Vitro

Corn bran is exceptionally rich in substituted glucuronoarabinoxylan polysaccharides, which are monoferuloylated and cross-linked by diferulic acid moieties. Here, we assessed the potential prebiotic activity of three enzymatically solubilized corn bran glucuronoarabinoxylans: medium feruloylated (FGAX-M), laccase cross-linked FGAX-M (FGAX-H), and alkali-treated FGAX-M devoid of feruloyl substitutions (FGAX-B). We examined the influence of these soluble FGAX samples on the gut microbiome composition and functionality during in vitro simulated colon fermentations, determined by 16S rRNA gene amplicon sequencing and assessment of short-chain fatty acid (SCFAs) production. All FGAX samples induced changes in the relative composition of the microbiota and the SCFA levels after 24 h of in vitro fermentation. The changes induced by FGAX-M and FGAX-H tended to be more profound and more similar to the changes induced by inulin than changes conferred by FGAX-B. The microbiota changes induced by FGAX-M and FGAX-H correlated with an increase in the relative abundance of Anaerostipes and with increased butyric acid production, while the changes induced by the FGAX-B sample were less compelling. The results imply that solubilized, substituted diferuloylated corn bran glucuronoarabinoxylans may be potential prebiotic candidates and that both single feruloylations and diferuloyl cross-links influence the prebiotic potential of these arabinoxylan compounds.

Gut Microbiome and Its Impact on Obesity and Obesity-Related Disorders

PURPOSE OF REVIEW

The prevalence of overweight and obesity has been increasing worldwide at an alarming rate. Gut microbiota intimately influence host energy metabolism, and immune response. Studies indicate a prominent role of gut dysbiosis in propagating inflammation that is associated with the development of obesity and obesity-related disorders such as type 2 diabetes mellitus, metabolic syndrome, and non-alcoholic fatty liver disease. This article will review the current literature on gut microbiome and its impact on obesity and obesity-related disorders.

RECENT FINDINGS

An altered gut microbial composition in obesity and obesity-related disorders is associated with enhanced energy extraction from the non-digestible dietary carbohydrates, increased gut permeability, increased production of proinflammatory metabolites, such as lipopolysaccharides, resulting in systemic inflammation and insulin resistance. Gut microbiota modulation can be achieved either by dietary manipulation or by administration of probiotics, prebiotics, synbiotics, and/or fecal microbiota transplantation aiming at the improvement of the gut dysbiosis in obesity and metabolic disorders. Further clinical trials are required to better elucidate the dose, and frequency of these interventions and also their long-term impact on host metabolism.

The gut microbiome and child mental health: A population-based study

The link between the gut microbiome and the brain has gained increasing scientific and public interest for its potential to explain psychiatric risk. While differences in gut microbiome composition have been associated with several mental health problems, evidence to date has been largely based on animal models and human studies with modest sample sizes. In this cross-sectional study in 1,784 ten-year-old children from the multi-ethnic, population-based Generation R Study, we aimed to characterize associations of the gut microbiome with child mental health problems. Gut microbiome was assessed from stool samples using 16S rRNA sequencing. We focused on overall psychiatric symptoms as well as with specific domains of emotional and behavioral problems, assessed via the maternally rated Child Behavior Checklist. While we observed lower gut microbiome diversity in relation to higher overall and specific mental health problems, associations were not significant. Likewise, we did not identify any taxonomic feature associated with mental health problems after multiple testing correction, although suggestive findings indicated depletion of genera previously associated with psychiatric disorders, including Hungatella, Anaerotruncus and Oscillospiraceae. The identified compositional abundance differences were found to be similar across all mental health problems. Finally, we did not find significant enrichment for specific microbial functions in relation to mental health problems. In conclusion, based on the largest sample examined to date, we do not find clear evidence of associations between gut microbiome diversity, taxonomies or functions and mental health problems in the general pediatric population. In future, the use of longitudinal designs with repeated measurements of microbiome and psychiatric outcomes will be critical to identify whether and when associations between the gut microbiome and mental health emerge across development and into adulthood.

Shimanami Leaf Intake Affects Bowel Movement and Intestinal Microbiota in Mice

The Shimanami Leaf^®, produced at Innoshima Island in Onomichi City, Hiroshima Prefecture, Japan, is a leafy vegetable that does not require pesticide use and has a high nutritional value. Although the leaf has abundant dietary fiber and other nutrients, reports on its biological regulatory functions are lacking. Therefore, this study aimed to elucidate the effects of Shimanami leaf intake on bowel movement and gut microbiota in mice. We examined the effects of Shimanami leaves on fecal weight, fecal water content, and intestinal microbiota composition. On day 10 of administration, the Shimanami leaf-treated group exhibited significantly higher fecal weight and water content than the control group. Next-generation sequencing analysis revealed that the ingestion of Shimanami leaf increased the abundances and diversity of intestinal bacteria, including members from Lactococcus, Streptococcus, and Muribaculaceae. Our findings suggest that Shimanami leaf supplementation improves bowel movement and promotes defecation.

Gut microbiota and transcriptome profiling revealed the protective effect of aqueous extract of Tetrastigma hemsleyanum leaves on ulcerative colitis in mice

Tetrastigma hemsleyanum, a traditional Chinese medicinal plant, possesses various biological activities, including anti-inflammatory and immunomodulatory functions. The purpose of this study was to determine the alleviating effect of the water extract of Tetrastigma hemsleyanum leaves (THLW) on ulcerative colitis (UC) and its relationship with gut microbiota. The administration of THLW significantly decreased the severity of dextran sulfate sodium (DSS)-induced intestinal damage, as demonstrated by the stabilization of body weight and colon length, and decreased disease activity index (DAI) and histological scores. THLW also decreased NF-κB protein expression in colon tissues and reduced the serum levels of IL-6, IL-1β, and TNF-α. Further co-housing experiment confirmed that the anti-UC effect of THLW was possibly by regulating the structure and composition of gut microbiota, including increasing the abundance of Oscillospiraceae, Prevotellaceae and Corynebacterium. Additionally, the expression of genes related to inflammation and immunity was also regulated by THLW treatment as evidenced by transcriptome analysis. These results suggested that the protective effect of THLW on DSS-induced colitis was mediated by alleviating inflammation and modulating the microbiota composition. This work proved the potent protective effects of THLW treatment on colitis and may have potential for UC relief.

Analysis of the gut microbiome in obese native Tibetan children living at different altitudes: A case-control study

Objective

To explore the relationship between intestinal flora and obesity in Tibetan children at different altitudes.

Methods

Using16S rRNA gene sequencing results and blood lipid metabolism indexes to study the characteristics of the intestinal flora present in faeces and changes in blood lipid metabolism in obese children in Tibet who reside at different altitudes and to study correlations between blood lipid metabolism indicators and the intestinal flora composition.

Results

The results showed the following. (a) The triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) levels in the obesity groups were higher than those in the normal-weight groups, and those in the high-altitude obesity groups were lower than those in the low-altitude obesity groups. (b) The 16S rRNA gene sequencing results showed that altitude affected the composition and relative abundance of the gut microbiota. These parameters were basically the same among the low-altitude groups, while they were significantly lower in the high-altitude groups than in the low-altitude groups. (c) Groups that lived at different altitudes and had different body weights had different dominant bacterial genera. Megamonas was closely related to obesity, and its relative abundance in the low-altitude groups was higher than that in the high-altitude groups. Prevotella was associated with altitude, and its relative abundance in the high-altitude groups was higher than that in the low-altitude groups. In addition, Prevotella elicited changes in the abundance of Escherichia-Shigella. The lower prevalence of obesity and incidence of intestinal inflammation in those living at high altitudes were related to the abundance of Prevotella. (d) There were correlations between the gut microbiota composition and lipid metabolism indicators. The abundance of Romboutsia was positively correlated with TG and LDL-C levels but negatively correlated with high-density lipoprotein cholesterol (HDL-C) levels. The abundance of Akkermansia was negatively correlated with LDL-C levels, and the abundance of Blautia was negatively correlated with body mass index (BMI) and LDL-C levels.

Conclusions

The intestinal flora diversity varied by body weight and altitude, with lower diversity in those at higher altitudes and with lower body weights. Prevotella likely plays a role in suppressing obesity at high altitudes.

Regulation of viable/inactivated/lysed probiotic Lactobacillus plantarum H6 on intestinal microbiota and metabolites in hypercholesterolemic mice

Evidence suggests that probiotic interventions reduce non-communicable diseases (NCDs) risk. However, its therapeutic effect and mechanism are still unclear. To evaluate the hypocholesterolemic effect of Lactobacillus plantarum H6 (L.p H6), a new commercial patent strain capable of preventing hypercholesterolemia, and its mechanism in depth, three states of the strain were prepared, namely, viable (vH6), heat-inactivated (iH6), and ultrasonically-lysed (uH6) bacteria cells. The results showed that v/i/uH6 cells could lower serum and liver blood lipid levels, alleviate liver damage and improve glucose tolerance test (GTT) and insulin tolerance test (ITT) indexes. v/i/uH6 cells improved the gut microbial composition and significantly reduced the Firmicutes to Bacteroidetes ratio (F/B ratio) in feces. In particular, Muribaculaceae may be a potential biomarker for effective cholesterol reduction. Also, the recovery of these biochemical indices and gut microbiome was found following fecal microbiota transplantation (FMT) using stool from vH6 treated mice. The v/i/uH6 cells increased the intestinal flora metabolism of vitamins-cofactors, as well as amino acids, while decreasing the relative content of primary bile acids. The Pearson correlation analysis showed that norank_f__Muribaculaceae and Lactobacillus had a negative correlation with blood lipid levels. Overall, v/i/uH6 cells were effective in improving hypercholesterolemia in mice, and this effect was attributed partly to the regulation of intestinal microbiota and metabolites related to lipid metabolism. Our findings provided a theoretical basis for the industrial development of probiotics and postbiotics and the treatment of cholesterol diseases.

Effects of Danggui Buxue decoction on host gut microbiota and metabolism in GK rats with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by persistent abnormally elevated blood sugar levels. T2DM affects millions of people and exerts a significant global public health burden. Danggui Buxue decoction (DBD), a classical Chinese herbal formula composed of Astragalus membranaceus (Huangqi) and Angelica sinensis (Danggui), has been widely used in the clinical treatment of diabetes and its complications. However, the effect of DBD on the gut microbiota of individuals with diabetes and its metabolism are still poorly understood. In this study, a T2DM model was established in Goto-Kakizaki (GK) rats, which were then treated with a clinical dose of DBD (4 g/kg) through tube feeding for 6 weeks. Next, we used 16S rRNA sequencing and untargeted metabolomics by liquid chromatography with mass spectrometry (LC-MS) to detect changes in the composition of the microbiota and cecal metabolic products. Our data show that DBD mediates the continuous increase in blood glucose in GK rats, improves insulin sensitivity, reduces expression of inflammatory mediators, and improves systemic oxidative stress. Moreover, DBD also improves microbial diversity (e.g., Romboutsia, Firmicutes, and Bacilli) in the intestines of rats with T2DM. Further, DBD intervention also regulates various metabolic pathways in the gut microbiota, including alanine, aspartate, and glutamate metabolism. In addition, arginine biosynthesis and the isoflavone biosynthesis may be a unique mechanism by which DBD exerts its effects. Taken together, we show that DBD is a promising therapeutic agent that can restore the imbalance found in the gut microbiota of T2DM rats. DBD may modify metabolites in the microbiota to realize its antidiabetic and anti-inflammatory effects.

Importance of Microbiome of Fecal Samples Obtained from Adolescents with Different Weight Conditions on Resistance Gene Transfer

Antimicrobial resistance (AMR) is a relevant public health problem worldwide, and microbiome bacteria may contribute to the horizontal gene transfer associated with antimicrobial resistance. The microbiome of fecal samples from Mexican adolescents were analyzed and correlated with eating habits, and the presence of AMR genes on bacteria in the microbiome was evaluated. Fecal samples from adolescents were collected and processed to extract genomic DNA. An Illumina HiSeq 1500 system was used to determine resistance genes and the microbiome of adolescents through the amplification of gene resistance and the V3–V4 regions of RNA, respectively. Analysis of the microbiome from fecal samples taken from 18 obese, overweight, and normal-weight adolescents revealed that the Firmicutes was the most frequent phylum, followed by Bacteroidetes, Actinobacteria, Proteobacteria and Verrucomicrobia. The following species were detected as the most frequent in the samples: F. prausnitzii, P. cori, B. adolescentis, E. coli and A. muciniphila. The presence of Bacteroides, Prevotella and Ruminococcus was used to establish the enterotype; enterotype 1 was more common in women and enterotype 2 was more common in men. Twenty-nine AMR genes were found for β-lactamases, fluoroquinolones, aminoglycosides, macrolide, lincosamides, streptogramin (MLS), tetracyclines and sulfonamides. The presence of microorganisms in fecal samples that harbor AMR genes that work against antimicrobials frequently used for the treatment of microbial infections such as b-lactams, macrolides, aminoglycosides, MLS, and tetracyclines is of great concern, as these organisms may be an important reservoir for horizontal AMR gene transfer.

Comparative analysis of gut microbiota and fecal metabolome features among multiple depressive animal models

BACKGROUNDS

Emerging studies reported that gut microbiota and fecal metabolites take part in major depressive disorder (MDD) pathogenesis. However, the conclusions based on a single depressive animal model seem inconsistent or even controversial.

METHODS

Multiple depression rat models, including chronic unpredictable mild stress, chronic restraint stress, social defeat, and learned helplessness, were used. Then, the 16S ribosomal RNA gene sequencing and liquid chromatography-mass spectrometry analysis determined the alteration of gut microbiota and fecal metabolites.

RESULTS

The results of sucrose preference test and forced swimming test suggested that each model successfully established depression-like behavior. A total of 179 discriminative amplicon sequence variants (ASVs) were identified among four models. The overall discriminative ASVs mainly belonged to the family Lachnospiraceae, Muribaculaceae, and Oscillospiraceae. Moreover, the fecal metabolomic analysis identified 468 differential expressed metabolites. Among all the differential metabolites, 11 specific pathways significantly altered, which were mainly belonged to lipid and amino acid metabolism. Finally, co-occurrence network analysis suggested that target differential metabolites were associated with discriminative ASVs mainly assigned to family taxon Lachnospiraceae, Muribaculaceae, and Oscillospiraceae.

LIMITATIONS

The heterogeneity of MDD in humans cannot be totally imitated by animal models.

CONCLUSIONS

In multiple depression models, the alterations of family Lachnospiraceae, Muribaculaceae, and Oscillospiraceae with the dysbiosis of lipid and amino acid metabolism were gut microbiota and fecal metabolome features. The findings of our research may help us to have a comprehensive understanding of gut microbiota and fecal metabolome in depression.

Bifidobacterium longum 070103 Fermented Milk Improve Glucose and Lipid Metabolism Disorders by Regulating Gut Microbiota in Mice

Background: Fermented milk is beneficial for metabolic disorders, while the underlying mechanisms of action remain unclear. This study explored the benefits and underlying mechanisms of Bifidobacterium longum 070103 fermented milk (BLFM) in thirteen-week high-fat and high-sugar (HFHS) fed mice using omics techniques. Methods and results: BLFM with activated glucokinase (GK) was screened by a double-enzyme coupling method. After supplementing BLFM with 10 mL/kg BW per day, fasting blood glucose, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and leptin were significantly reduced compared with the HFHS group. Among them, the final body weight (BW), epididymal fat, perirenal fat, and brown fat in BLFM group had better change trends than Lacticaseibacillus rhamnosus GG fermented milk (LGGFM) group. The amplicon and metabolomic data analysis identified Bifibacterium as a key gut microbiota at regulating glycolipid metabolism. BLFM reverses HFHS-induced reduction in bifidobacteria abundance. Further studies showed that BLFM significantly reduces the content of 3-indoxyl sulofphate associated with intestinal barrier damage. In addition, mice treated with BLFM improved BW, glucose tolerance, insulin resistance, and hepatic steatosis. Conclusion: BLFM consumption attenuates obesity and related symptoms in HFHS-fed mice probably via the modulation of gut microbes and metabolites.

Dietary Supplementation with Sea Buckthorn Berry Puree Alters Plasma Metabolomic Profile and Gut Microbiota Composition in Hypercholesterolemia Population

Sea buckthorn berries have been reported to have beneficial effects on plasma lipid profile and cardiovascular health. This study aimed to investigate the impact of intervention with sea buckthorn berry puree on plasma metabolomics profile and gut microbiota in hypercholesterolemic subjects. A total of 56 subjects with hypercholesterolemia consumed 90 g of sea buckthorn berry puree daily for 90 days, and plasma metabolomic profile was studied at 0 (baseline), 45, and 90 days of intervention by using proton nuclear magnetic resonance spectroscopy (¹H NMR). Gut microbiota composition was analyzed at the baseline and after 90 days of supplementation by using high-throughput sequencing. The plasma metabolic profile was significantly altered after 45 days of intervention as compared to the baseline (day 0). A clear trend of returning to the baseline metabolomic profile was observed in plasma when the intervention extended from 45 days to 90 days. Despite this, the levels of several key plasma metabolites such as glucose, lactate, and creatine were lowered at day 90 compared to the baseline levels, suggesting an improved energy metabolism in those patients. In addition, intervention with sea buckthorn puree enriched butyrate-producing bacteria and other gut microbes linked to lipid metabolisms such as Prevotella and Faecalibacterium while depleting Parasutterella associated with increased risks of cardiovascular disease. These findings indicate that sea buckthorn berries have potential in modulating energy metabolism and the gut microbiota composition in hypercholesterolemic patients.

Archaea from the gut microbiota of humans: Could be linked to chronic diseases?

Archaea comprise a unique domain of organisms with distinct biochemical and genetic differences from bacteria. Methane-forming archaea, methanogens, constitute the predominant group of archaea in the human gut microbiota, with Methanobrevibacter smithii being the most prevalent. However, the effect of methanogenic archaea and their methane production on chronic disease remains controversial. As perturbation of the microbiota is a feature of chronic conditions, such as cardiovascular disease, neurodegenerative diseases and chronic kidney disease, assessing the influence of archaea could provide a new clue to mitigating adverse effects associated with dysbiosis. In this review, we will discuss the putative role of archaea in the gut microbiota in humans and the possible link to chronic diseases.

Gut microbiome is associated with metabolic syndrome accompanied by elevated gamma-glutamyl transpeptidase in men

It is predicted that by 2035, metabolic syndrome (MS) will be found in nearly more than half of our adult population, seriously affecting the health of our body. MS is usually accompanied by the occurrence of abnormal liver enzymes, such as elevated gamma-glutamyl transpeptidase (GGT). More and more studies have shown that the gut microbiota is involved in MS; however, the correlation between gut microbiota and MS with elevated GGT has not been studied comprehensively. Especially, there are few reports about its role in the physical examination of the population of men with MS and elevated GGT. By using the whole-genome shotgun sequencing technology, we conducted a genome-wide association study of the gut microbiome in 66 participants diagnosed as having MS accompanied by high levels of GGT (case group) and 66 participants with only MS and normal GGT level (control group). We found that the number of gut microbial species was reduced in participants in the case group compared to that of the control group. The overall microbial composition between the two groups is of significant difference. The gut microbiota in the case group is characterized by increased levels of “harmful bacteria” such as Megamonas hypermegale, Megamonas funiformis, Megamonas unclassified, Klebsiella pneumoniae, and Fusobacterium mortiferum and decreased levels of “beneficial bacteria” such as Faecalibacterium prausnitzii, Eubacterium eligens, Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bacteroides dorei, and Alistipes putredinis. Moreover, the pathways of POLYAMSYN-PWY, ARG+POLYAMINE-SYN, PWY-6305, and GOLPDLCAT-PWY were also increased in the case group, which may play a role in the elevation of GGT by producing amine, polyamine, putrescine, and endogenous alcohol. Taken together, there are apparent changes in the composition of the gut microbiome in men with MS and abnormal GGT levels, and it is high time to discover specific gut microbiome as a potential therapeutic target in that population. More in-depth studies of relevant mechanism could offer some new methods for the treatment of MS with elevated GGT.

Human Adult Microbiota in a Static Colon Model: AhR Transcriptional Activity at the Crossroads of Host–Microbe Interaction

Functional symbiotic intestinal microbiota regulates immune defense and the metabolic processing of xenobiotics in the host. The aryl hydrocarbon receptor (AhR) is one of the transcription factors mediating host–microbe interaction. An in vitro static simulation of the human colon was used in this work to analyze the evolution of bacterial populations, the microbial metabolic output, and the potential induction of AhR transcriptional activity in healthy gut ecosystems. Fifteen target taxa were explored by qPCR, and the metabolic content was chromatographically profiled using SPME-GC-MS and UPLC-FLD to quantify short-chain fatty acids (SCFA) and biogenic amines, respectively. Over 72 h of fermentation, the microbiota and most produced metabolites remained stable. Fermentation supernatant induced AhR transcription in two of the three reporter gene cell lines (T47D, HepG2, HT29) evaluated. Mammary and intestinal cells were more sensitive to microbiota metabolic production, which showed greater AhR agonism than the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) used as a positive control. Some of the SCFA and biogenic amines identified could crucially contribute to the potent AhR induction of the fermentation products. As a fundamental pathway mediating human intestinal homeostasis and as a sensor for several microbial metabolites, AhR activation might be a useful endpoint to include in studies of the gut microbiota.

SARS-CoV-2 and Prevotella spp.: friend or foe? A systematic literature review

During this global pandemic of the COVID-19 disease, a lot of information has arisen in the media and online without scientific validation, and among these is the possibility that this disease could be aggravated by a secondary bacterial infection such as Prevotella, as well as the interest or not in using azithromycin, a potentially active antimicrobial agent. The aim of this study was to carry out a systematic literature review, to prove or disprove these allegations by scientific arguments. The search included Medline, PubMed, and Pubtator Central databases for English-language articles published 1999-2021. After removing duplicates, a total of final eligible studies (n=149) were selected. There were more articles showing an increase of Prevotella abundance in the presence of viral infection like that related to Human Immunodeficiency Virus (HIV), Papillomavirus (HPV), Herpesviridae and respiratory virus, highlighting differences according to methodologies and patient groups. The arguments for or against the use of azithromycin are stated in light of the results of the literature, showing the role of intercurrent factors, such as age, drug consumption, the presence of cancer or periodontal diseases. However, clinical trials are lacking to prove the direct link between the presence of Prevotella spp. and a worsening of COVID-19, mainly those using azithromycin alone in this indication.

Evaluation of the Effects of a Short Supplementation With Tannins on the Gut Microbiota of Healthy Subjects

Western diet, high in fats and sugars and low in greens, contributes to dysbiosis of the gut microbiota, which can lead to a variety of chronic diseases related with inflammation. Supplementation with bioactive compounds can help to maintain a healthy eubiotic state. Thus, we performed a 4-weeks nutritional intervention on healthy volunteers to investigate whether a blend of natural tannin extracts could induce healthy changes in the microbial intestinal ecosystem. Changes in the composition and functionality of the microbiota could be observed from the first two weeks onward. 16S rRNA amplicon next-generation sequencing (NGS) revealed a significant increase in microbial diversity at the end of the intervention, as well as trends toward increases in the relative abundances of several beneficial taxa, such as Ruminococcus bicirculans, Faecalibacterium prausnitzii, Lachnospiraceae UCG 010, Lachnospiraceae NK4A136, Bacteroides thetaiotaomicron and B. uniformis. Remarkably, some of the identified taxa were also identified as responsible for an increase in the production of short-chain fatty acids (SCFAs), microbial metabolites that contribute to the modulation of the immune system and have various other anti-inflammatory functions in the gut. Taken together, these results suggest that the tannin supplementation could exert a prebiotic effect by selectively stimulating the growth and the activity of bacteria that are advantageous for the host.

Multi-Omics Association Reveals the Effects of Intestinal Microbiome–Host Interactions on Fat Deposition in Broilers

Growing evidence indicates that gut microbiota factors cannot be viewed as independent in the occurrence of obesity. Because the gut microbiome is highly dimensional and complex, studies on interactions between gut microbiome and host in obesity are still rare. To explore the relationship of gut microbiome–host interactions with obesity, we performed multi-omics associations of gut metagenome, intestinal transcriptome, and host obesity phenotypes in divergently selected obese–lean broiler lines. Metagenomic shotgun sequencing generated a total of 450 gigabases of clean data from 80 intestinal segment contents of 20 broilers (10 of each line). The microbiome comparison showed that microbial diversity and composition in the duodenum, jejunum, ileum, and ceca were altered variously between the lean- and fat-line broilers. We identified two jejunal microbes (Escherichia coli and Candidatus Acetothermia bacterium) and four cecal microbes (Alistipes sp. CHKCI003, Ruminococcaceae bacterium CPB6, Clostridiales bacterium, and Anaeromassilibacillus sp. An200), which were significantly different between the two lines (FDR < 0.05). When comparing functional metagenome, the fat-line broilers had an intensive microbial metabolism in the duodenum and jejunum but degenerative microbial activities in the ileum and ceca. mRNA-sequencing identified a total of 1,667 differentially expressed genes (DEG) in the four intestinal compartments between the two lines (| log2FC| > 1.5 and FDR < 0.05). Multi-omics associations showed that the 14 microbial species with abundances that were significantly related with abdominal fat relevant traits (AFRT) also have significant correlations with 155 AFRT-correlated DEG (p < 0.05). These DEG were mainly involved in lipid metabolism, immune system, transport and catabolism, and cell growth-related pathways. The present study constructed a gut microbial gene catalog of the obese–lean broiler lines. Intestinal transcriptome and metagenome comparison between the two lines identified candidate DEG and differential microbes for obesity, respectively. Multi-omics associations suggest that abdominal fat deposition may be influenced by the interactions of specific gut microbiota abundance and the expression of host genes in the intestinal compartments in which the microbes reside. Our study explored the interactions between gut microbiome and host intestinal gene expression in lean and obese broilers, which may expand knowledge on the relationships between obesity and gut microbiome.

Taxonomic and Functional Fecal Microbiota Signatures Associated With Insulin Resistance in Non-Diabetic Subjects With Overweight/Obesity Within the Frame of the PREDIMED-Plus Study

OBJECTIVE

An altered gut microbiota has been associated with insulin resistance, a metabolic dysfunction consisting of cellular insulin signaling impairment. The aim of the present study is to determine the taxonomic and functional fecal microbiota signatures associated with HOMA-IR index in a population with high cardiovascular risk.

METHODS

A total of 279 non-diabetic individuals (55-75 years aged) with overweight/obesity and metabolic syndrome were stratified according to tertiles of HOMA-IR index. Blood biochemical parameters, anthropometric measurements and fecal samples were collected at baseline. Fecal microbial DNA extraction, 16S amplicon sequencing and bioinformatics analysis were performed.

RESULTS

Desulfovibrio, Odoribacter and Oscillospiraceae UCG-002 were negatively associated with HOMA-IR index, whereas predicted total functional abundances revealed gut metabolic modules mainly linked to amino acid degradation. Butyricicoccus, Erysipelotrichaceae UCG-003, Faecalibacterium were positively associated with HOMA-IR index, whereas predicted total functional abundances revealed gut metabolic modules mainly linked to saccharide degradation. These bacteria contribute differentially to the gut metabolic modules, being the degree of contribution dependent on insulin resistance. Both taxa and gut metabolic modules negatively associated to HOMA-IR index were linked to mechanisms involving sulfate reducing bacteria, improvement of intestinal gluconeogenesis and production of acetate. Furthermore, both taxa and gut metabolic modules positively associated to HOMA-IR index were linked to production and mechanisms of action of butyrate.

CONCLUSIONS

Specific taxonomic and functional fecal microbiota signatures associated with insulin resistance were identified in a non-diabetic population with overweight/obesity at high cardiovascular risk. These findings suggest that tailoring therapies based on specific fecal microbiota profiles could be a potential strategy to improve insulin sensitivity.

Polysaccharides from Sargassum fusiforme after UV/H2O2 degradation effectively ameliorate dextran sulfate sodium-induced colitis

In this study, degraded polysaccharides from Sargassum fusiforme (PSF-T2) were prepared by UV/H2O2 treatment for 2 h, and its effects on ameliorating dextran sulfate sodium-induced colitis were evaluated using a mouse model. Results showed that PSF-T2 relieved colitis symptoms, characterized by increasing the colon length and body weight, decreasing disease activity index and relieving colon damage. In addition, PSF-T2 decreased the secretion and expression of IL-1β, IL-6 and TNF-α, and increased the expression of MUC-2, ZO-1 and occludin. Besides, PSF-T2 promoted the production of short-chain fatty acids and modulated gut microbiota composition (increasing the abundance of Lactobacillaceae, Lachnospiraceae, Oscillospiraceae and Desulfovibrionaceae, and decreasing Bacteroidaceae and Erysipelotrichaceae). These results suggested that polysaccharides from Sargassum fusiforme after UV/H2O2 degradation could ameliorate colitis by decreasing inflammation, protecting the intestinal barrier and modulating gut microbiota. It can provide a theoretical basis for the preparation of bioactive polysaccharides by free radical degradation.

Characterization of the gut microbiota in hemodialysis patients with sarcopenia

PURPOSE

Maintenance hemodialysis (MHD) patients are at high risk of sarcopenia. Gut microbiota affects host metabolic and may act in the occurrence of sarcopenia importantly. This study aimed to study the characterization of the gut microbiota in MHD patients with sarcopenia, and to further reveal the complex pathophysiology of sarcopenia in MHD patients.

METHODS

Fecal samples and clinical data were collected from 30 MHD patients with sarcopenia, and 30 age-and-sex-matched MHD patients without sarcopenia in 1 general hospital of Jiangsu Province from December 2020 to March 2021. 16S rRNA sequencing technology was used to analyze the genetic sequence of the gut microbiota for evaluation of the diversity, species composition, and differential microbiota of the two groups.

RESULTS

Compared to MHD patients without sarcopenia, the ACE index of patients with sarcopenia was lower (P = 0.014), and there was a structural difference in the β-diversity between the two groups (P = 0.001). At the genus level, the relative abundance of Tyzzerella_4 in the sarcopenia group was significantly higher than in the non-sarcopenia group (P = 0.039), and the relative abundance of Megamonas (P = 0.004), Coprococcus_2 (P = 0.038), and uncultured_bacterium_f_Muribaculaceae (P = 0.040) decreased significantly.

CONCLUSION

The diversity and structure of the gut microbiota of MHD patients with sarcopenia were altered. The occurrence of sarcopenia in MHD patients may be influenced by gut microbiota.

Maternal IgA2 Recognizes Similar Fractions of Colostrum and Fecal Neonatal Microbiota

Microbiota acquired during labor and through the first days of life contributes to the newborn’s immune maturation and development. Mother provides probiotics and prebiotics factors through colostrum and maternal milk to shape the first neonatal microbiota. Previous works have reported that immunoglobulin A (IgA) secreted in colostrum is coating a fraction of maternal microbiota. Thus, to better characterize this IgA-microbiota association, we used flow cytometry coupled with 16S rRNA gene sequencing (IgA-Seq) in human colostrum and neonatal feces. We identified IgA bound bacteria (IgA+) and characterized their diversity and composition shared in colostrum fractions and neonatal fecal bacteria. We found that IgA2 is mainly associated with Bifidobacterium, Pseudomonas, Lactobacillus, and Paracoccus, among other genera shared in colostrum and neonatal fecal samples. We found that metabolic pathways related to epithelial adhesion and carbohydrate consumption are enriched within the IgA2+ fecal microbiota. The association of IgA2 with specific bacteria could be explained because these antibodies recognize common antigens expressed on the surface of these bacterial genera. Our data suggest a preferential targeting of commensal bacteria by IgA2, revealing a possible function of maternal IgA2 in the shaping of the fecal microbial composition in the neonate during the first days of life.

A Possible Perspective about the Compositional Models, Evolution, and Clinical Meaning of Human Enterotypes

Among the various parameters obtainable through the analysis of the human gut microbiota, the enterotype is one of the first classifications of the bacterial consortia, which tried to obtain, at the same time, as much information as possible to be applied in clinical medicine. Although some authors observed the existence not of clusters, but only of a real continuous gradient, enterotypes are commonly described according to various models. The first model predicted either clustering into enterotypes 1 and 2 based on two specific dominances, Bacteroides and Prevotella, respectively, with the Ruminococcus dominance blurred within the Bacteroides dominance, or it predicted a threedominant condition, in which the Ruminococcus driver constituted enterotype 3, separated from enterotype 1. A second model envisaged three possible ways to cluster gut microbiota, respectively centred on two, three, and four dominances. In the first case, enterotypes 1 and 2 coincided with the two original enterotypes, with the dominance of Bacteroides and Prevotella, respectively. In the second case, the existence of enterotype 3 was evident and whose dominance was not centred on Ruminococcus but extended more towards the entire Firmicutes phylum. In the third case, the presence of the phylum Firmicutes was split into two different enterotypes generating the clusters defined and named as Mixtures 1 and 2. Subsequently, the analysis of the water content (hydration) in the stool allowed the splitting of the Bacteroides enterotype into two sub-enterotype, respectively known as B1 and B2. All these models have allowed us to highlight some correlations between a specific enterotype, or cluster, and some characteristics, such as the greater predisposition of the respective hosts towards certain pathologies. These observations, coupled with the attempt to derive the different microbiota on an evolutionary basis, can help to shed new light on this topic and demonstrate the possible utility that the different ways of clustering the gut microbiota can have in a clinical application perspective and in preventive medicine.

Personalized approach to childhood obesity: Lessons from gut microbiota and omics studies. Narrative review and insights from the 29th European childhood obesity congress

The traditional approach to childhood obesity prevention and treatment should fit most patients, but misdiagnosis and treatment failure could be observed in some cases that lie away from average as part of individual variation or misclassification. Here, we reflect on the contributions that high-throughput technologies such as next-generation sequencing, mass spectrometry-based metabolomics and microbiome analysis make towards a personalized medicine approach to childhood obesity. We hypothesize that diagnosing a child as someone with obesity captures only part of the phenotype; and that metabolomics, genomics, transcriptomics and analyses of the gut microbiome, could add precision to the term "obese," providing novel corresponding biomarkers. Identifying a cluster -omic signature in a given child can thus facilitate the development of personalized prognostic, diagnostic, and therapeutic approaches. It can also be applied to the monitoring of symptoms/signs evolution, treatment choices and efficacy, predisposition to drug-related side effects and potential relapse. This article is a narrative review of the literature and summary of the main observations, conclusions and perspectives raised during the annual meeting of the European Childhood Obesity Group. Authors discuss some recent advances and future perspectives on utilizing a systems approach to understanding and managing childhood obesity in the context of the existing omics data.

Distinctive Gut Microbiota in Patients with Overweight and Obesity with Dyslipidemia and its Responses to Long-term Orlistat and Ezetimibe Intervention: A Randomized Controlled Open-label Trial

This study investigated the gut microbiota and short chain fatty acids (SCFAs) characteristics of subjects with obesity from Xinjiang in northwestern China, a region with a multiethnic culture and characteristic lifestyle, and to explore the potential microbes that respond to a 12-wk medication of orlistat and ezetimibe with a randomized controlled open-label trial manner. The gut microbiota profile of patients with overweight and obesity with dyslipidemia in Xinjiang was distinctive and characterized by enrichment of Lactobacillus and the reduction of the diversity and the depletion of Actinobacteria, Bacteroides, Bifidobacterium, and Bacteroides fragilis. Prevotella-type, Gemmiger-type, and Escherichia/Shigella-type were the gut microbial patterns of the Xinjiang population. However, the fecal SCFAs levels and enterotypes were similar between healthy individuals and patients. These results indicated that the contribution of the gut microbiota to obesity was highly dependent on geography and dietary habits. Waist circumference, total triglyceride (TG), and fasting blood glucose (FBG) were significantly decreased after orlistat therapy, whereas TG, total cholesterol (TC), and low density lipoprotein cholesterol (LDL-C) were significantly decreased by ezetimibe. Overall, the gut microbiota and their SCFAs metabolites were relatively stable after treatment with the two drugs, with alteration of some low-abundant bacteria, i.e., significantly increased Proteobacteria and decreased Alloprevotella after orlistat, and increased Fusobacteria and Fusobacterium after ezetimibe therapy. These results indicated that intestinal malabsorption of dietary fat and cholesterol caused by orlistat and ezetimibe had a limited effect on the overall gut microbial community and their metabolites. Nevertheless, significant correlations between several core microbes that responded to the medications and biochemical data were found; in particular, Actinomyces and Bacteroides were positively correlated with FBG after orlistat intervention, while Clostridium XVIII and Lachnospiracea incertae sedis were negatively correlated with TC and LDL-C after ezetimibe intervention, thus indicating their roles in improving glucolipid metabolism in obesity by acting as potential microbial targets.

Cudrania tricuspidata Combined with Lacticaseibacillus rhamnosus Modulate Gut Microbiota and Alleviate Obesity-Associated Metabolic Parameters in Obese Mice

The aim of the presented study was to investigate the synbiotic effects of L. rhamnosus 4B15 and C. tricuspidata extract administration on the gut microbiota and obesity-associated metabolic parameters in diet-induced obese mice. Thirty-one 6-week-old male C57BL/N6 mice were divided into five diet groups: normal diet (ND, n = 7) group; high-fat diet (HFD, n = 6) group; probiotic (PRO, n = 5) group; prebiotic (PRE, n = 7) group; and synbiotic (SYN, n = 6) group. After 10 weeks, the percent of fat mass, serum triglyceride, and ALT levels were significantly reduced in SYN-fed obese mice, compared with other treatments. SYN treatment also modulated the abundance of Desulfovibrio, Dorea, Adlercreutzia, Allobaculum, Coprococcus, unclassified Clostridiaceae, Lactobacillus, Helicobacter, Flexispira, Odoribacter, Ruminococcus, unclassified Erysipelotrichaceae, and unclassified Desulfovibrionaceae. These taxa showed a strong correlation with obesity-associated indices. Lastly, the SYN-supplemented diet upregulated metabolic pathways known to improve metabolic health. Further investigations are needed to understand the mechanisms driving the synbiotic effect of C. tricuspidata and L. rhamnosus 4B15.

Prediction of Gut Microbial Community Structure and Function in Polycystic Ovary Syndrome With High Low-Density Lipoprotein Cholesterol

Gut microbiota has been proved to be involved in the occurrence and development of many diseases, such as type 2 diabetes, obesity, coronary heart disease, etcetera. It provides a new idea for the pathogenesis of polycystic ovary syndrome (PCOS). Our study showed that the gut microbial community of PCOS with high low-density lipoprotein cholesterol (LDLC) has a noticeable imbalance. Gut microbiota of PCOS patients was significantly changed compared with CON, and these changes were closely related to LDLC. Gut microbiota may affect the metabolic level of PCOS patients through multiple metabolic pathways, and lipid metabolism disorder may further aggravate the imbalance of gut microbiota. Actinomycetaceae, Enterobacteriaceae and Streptococcaceae had high accuracy in the diagnosis of PCOS and the differentiation of subgroups, suggesting that they may play an important role in the diagnosis and treatment of PCOS in the future. Also, the model we built showed good specificity and sensitivity for distinguishing PCOS from CON (including L_CON and L_PCOS, H_CON and H_PCOS). In conclusion, this is the first report on the gut microbiota of PCOS with high LDLC, suggesting that in the drug development or treatment of PCOS patients, the difference of gut microbiota in PCOS patients with different LDLC levels should be fully considered.

Role of germ-free animal models in understanding interactions of gut microbiota to host and environmental health: A special reference to zebrafish

Numerous pieces of evidence documented the importance of gut microbiota in regulating human health and evaluating the toxicity of environmental pollutants, which are closely related to the host health in various aspects, including nutrition, energy translation, metabolism, pathogen resistance, and immune function. A variety of environmental factors can disrupt gut microbiota and their functions, and inevitably cause immune diseases, obesity and diabetes. However, deciphering the inner mechanisms involved in the functional interaction of gut microbes with host health is still needed extensive investigations. This review focused on the essential roles of intestinal microbes in host-related diseases and highlighted the development and applications of germ-free (GF) animal models, mainly zebrafish. Moreover, the generation, immunity characters, advantages and challenges of GF zebrafish models were also summarized. Importantly, the composition and isolation of zebrafish gut bacteria for further application and toxicity evaluation of aquatic environmental pollutants were also discussed. In conclusion, GF zebrafish play irreplaceable roles in understanding the potential functions and responses of customized microbiota towards human and environmental health implications.

Characterization of the gut microbiota in Chinese children with overweight and obesity using 16S rRNA gene sequencing

BACKGROUND

Childhood obesity constitutes a worldwide health problem, and the gut microbiota play extremely important roles in obesity. Herein, we aimed to characterize the gut microbiota in children of normal weight, overweight, and obesity.

METHODS

Thirty children of normal weight, 35 who were overweight, and 35 with obesity were enrolled from Nanjing, China. We isolated DNA from fecal samples, and employed 16S rRNA gene sequencing to explore the diversity and composition of gut microbiota.

RESULTS

The operational taxonomic unit (OTU) numbers exhibited a reduction in the gut microbiota abundance with the increase in the body weight. Alpha diversity analysis revealed a sharp decrease in the mean microbial abundance among the three groups (Chao1: F = 5.478, P = 0.006; observed species: F = 7.271, P = 0.001; PD whole tree: F = 8.735, P < 0.001). Beta diversity analysis indicated notable differences in the gut microbial composition between children of normal weight and obesity. However, overweight children had little difference in gut microbiota compared to either children of normal weight or obesity. At the genus level, Oscillospira decreased among the three groups (χ2 = 10.062, P = 0.001), and Sutterella increased (F = 4.052, P = 0.020). There were many remarkably increased species of gut bacteria in the comparison among three groups, 31 in the normal weight group, 32 in the obese group, and only three species of bacteria were identified in the overweight group. These significantly increased species of gut bacteria may have a close relationship with the progression of obesity.

CONCLUSIONS

The abundance of species decreased significantly as the BMI increased. Although the gut microbial composition between children of normal weight and obesity was notably different, due to the changing ratio of some microbial communities, gut microbiota in overweight children showed similarities to that of children with normal weight and obesity.

The Salivary miRNome: A Promising Biomarker of Disease

MicroRNAs (miRNAs) are non-coding RNAs ranging from 18-24 nucleotides also known to regulate the human genome mainly at the post-transcriptional level. MiRNAs were shown to play an important role in most biological processes such as apoptosis and in the pathogenesis of many diseases such as cardiovascular diseases and cancer. Recent developments of advanced molecular high-throughput technologies have enhanced our knowledge of miRNAs. MiRNAs can now be discovered, interrogated, and quantified in various body fluids, and hence can serve as diagnostic and therapeutic markers for many diseases. While most studies use blood as a sample source to measure circulating miRNAs as possible biomarkers for disease pathogenesis, fewer studies have assessed the role of salivary miRNAs in health and disease. This review aims at providing an overview of the current knowledge of the salivary miRNome, addressing the technical aspects of saliva sampling and highlighting the applicability of miRNA screening to clinical practice.

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

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

Dysbiosis of gut microbiota and its correlation with dysregulation of cytokines in psoriasis patients

Background

Psoriasis is an inflammatory skin disease associated with multiple comorbidities and substantially diminishes patients’ quality of life. The gut microbiome has become a hot topic in psoriasis as it has been shown to affect both allergy and autoimmunity diseases in recent studies. Our objective was to identify differences in the fecal microbial composition of patients with psoriasis compared with healthy individuals to unravel the microbiota profiling in this autoimmune disease.

Results

We collected fecal samples from 30 psoriasis patients and 30 healthy controls, sequenced them by 16S rRNA high-throughput sequencing, and identified the gut microbial composition using bioinformatic analyses including Quantitative Insights into Microbial Ecology (QIIME) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Our results showed that different relative abundance of certain bacterial taxa between psoriasis patients and healthy individuals, including Faecalibacterium and Megamonas, were increased in patients with psoriasis. It’s also implicated that many cytokines act as main effect molecules in the pathology of psoriasis. We selected the inflammation-related indicators that were abnormal in psoriasis patients and found the microbiome variations were associated with the level of them, especially interleukin-2 receptor showed a positive relationship with Phascolarctobacterium and a negative relationship with the Dialister. The relative abundance of Phascolarctobacterium and Dialister can be regard as predictors of psoriasis activity. The correlation analysis based on microbiota and Inflammation-related indicators showed that microbiota dysbiosis might induce an abnormal immune response in psoriasis.

Conclusions

We concluded that the gut microbiome composition in psoriasis patients has been altered markedly and provides evidence to understand the relationship between gut microbiota and psoriasis. More mechanistic experiments are needed to determine whether the differences observed in gut microbiota are the cause or consequences of psoriasis and whether the relationship between gut microbiota and cytokines was involved.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02125-1.