The Influence of the Gut Microbiome on Obesity, Metabolic Syndrome and Gastrointestinal Disease

CD71 + erythroid cells promote intestinal symbiotic microbial communities in pregnancy and neonatal period

BACKGROUND

The establishment of microbial communities in neonatal mammals plays a pivotal role in shaping their immune responses to infections and other immune-related conditions. This process is influenced by a combination of endogenous and exogenous factors. Previously, we reported that depletion of CD71 + erythroid cells (CECs) results in an inflammatory response to microbial communities in newborn mice.

RESULTS

Here, we systemically tested this hypothesis and observed that the small intestinal lamina propria of neonatal mice had the highest frequency of CECs during the early days of life. This high abundance of CECs was attributed to erythropoiesis niches within the small intestinal tissues. Notably, the removal of CECs from the intestinal tissues by the anti-CD71 antibody disrupted immune homeostasis. This disruption was evident by alteration in the expression of antimicrobial peptides (AMPs), toll-like receptors (TLRs), inflammatory cytokines/chemokines, and resulting in microbial dysbiosis. Intriguingly, these alterations in microbial communities persisted when tested 5 weeks post-treatment, with a more notable effect observed in female mice. This illustrates a sex-dependent association between CECs and neonatal microbiome modulation. Moreover, we extended our studies on pregnant mice, observing that modulating CECs substantially alters the frequency and diversity of their microbial communities. Finally, we found a significantly lower proportion of CECs in the cord blood of pre-term human newborns, suggesting a potential role in dysregulated immune responses to microbial communities in the gut.

CONCLUSIONS

Our findings provide novel insights into pivotal role of CECs in immune homeostasis and swift adaptation of microbial communities in newborns. Despite the complexity of the cellular biology of the gut, our findings shed light on the previously unappreciated role of CECs in the dialogue between the microbiota and immune system. These findings have significant implications for human health. Video Abstract.

Potential human health risk of the emerging environmental contaminant 6-PPD quinone

The tire antioxidant 6-PPD has been widely used to enhance tire performance and extend tire lifespan. 6-PPD quinone (6-PPDQ), a quinone derivative derived from 6-PPD in the presence of ozone, has been recognized an emerging environmental contaminant. In addition to causing acute lethality to coho salmon, 6-PPDQ exhibits toxic effects on other aquatic species and mammals. Based on the existing evidence, we provide a critical overview on the human internal exposure, potential adverse effects on health, and prediction of human health risk of 6-PPDQ. 6-PPDQ could be detected in human samples, including human urine, blood, and cerebrospinal fluid. Human exposure to 6-PPDQ in the environment is inevitable and may lead to adverse health effects, including hepatotoxicity, enterotoxicity, pulmonary toxicity, neurotoxicity, reproductive toxicity, and cardiotoxicity. Additionally, potential human health risk to 6-PPDQ through exposure routes and human samples were predicted. This review is helpful to identify the existing knowledge gaps and future research directions regarding the human health effects of 6-PPDQ.

Identification of volatile metabolites produced from levodopa metabolism by different bacteria strains of the gut microbiome

Interspecies pathways in the gut microbiome have been shown to metabolize levodopa, the primary treatment for Parkinson's disease, and reduce its bioavailability. While the enzymatic reactions have been identified, the ability to establish the resulting macromolecules as biomarkers of microbial metabolism remains technically challenging. In this study, we leveraged an untargeted mass spectrometry-based approach to investigate volatile organic compounds (VOCs) produced during levodopa metabolism by Enterococcus faecalis, Clostridium sporogenes, and Eggerthella lenta. We cultured these organisms with and without their respective bioactive metabolites and detected levodopa-induced shifts in VOC profiles. We then utilized bioinformatics to identify significant differences in 2,6-dimethylpyrazine, 4,6-dimethylpyrimidine, and 4,5-dimethylpyrimidine associated with its biotransformation. Supplementing cultures with inhibitors of levodopa-metabolizing enzymes revealed specific modulation of levodopa-associated diazines, verifying their relationship to its metabolism. Furthermore, functional group analysis depicts strain-specific VOC profiles that reflect interspecies differences in metabolic activity that can be leveraged to assess microbiome functionality in individual patients. Collectively, this work identifies previously uncharacterized metabolites of microbe-mediated levodopa metabolism to determine potential indicators of this activity and further elucidate the metabolic capabilities of different gut bacteria.

The Association Between Lactational Infective Mastitis and the Microbiome: Development, Onset, and Treatments

Lactational infective mastitis (LIM) was previously thought to occur due to trapped milk causing inadequate milk drainage and consequent infection. However, advances in genome sequencing techniques have shown that the abundance of Staphylococcus aureus, Staphylococcus epidermidis, Lactobacilli species, and Bifidobacterium species in the breast milk of lactating women play a key role in the development of LIM. Recent discoveries have revealed that the breast milk microbiome is composed of bacteria and other microorganisms, which are seeded through multiple pathways and are influenced by maternal factors. An imbalance in the microbial abundance in breast milk can lead to LIM. Given that this infection can cause early termination of breastfeeding, it is imperative to discuss prevention and treatment options. The objective of this review is to highlight the pathogens involved in LIM affecting human mothers, routes of bacterial transfer, and contributing factors that may influence changes in the composition of the milk microbiota, as well as propose preventative and curative treatment options.

Advances in molecular mechanisms of inflammatory bowel disease‑associated colorectal cancer (Review)

The link between inflammation and cancer is well documented and colonic inflammation caused by inflammatory bowel disease (IBD) is thought to be a high-risk factor for the development of colorectal cancer (CRC). The complex crosstalk between epithelial and inflammatory cells is thought to underlie the progression from inflammation to cancer. The present review collates and summarises recent advances in the understanding of the pathogenesis of IBD-associated CRC (IBD-CRC), including the oncogenic mechanisms of the main inflammatory signalling pathways and genetic alterations induced by oxidative stress during colonic inflammation, and discusses the crosstalk between the tumour microenvironment, intestinal flora and host immune factors during inflammatory oncogenesis in colitis-associated CRC. In addition, the therapeutic implications of anti-inflammatory therapy for IBD-CRC were discussed, intending to provide new insight into improve clinical practice.

Cohort profile of an early life observational cohort in China: Bone and MicroBiOme onset (BAMBOO) study

PURPOSE

The Bone And MicroBiOme Onset (BAMBOO) study is an ongoing prospective observational cohort study conducted in Tianjin, China, aiming to determine age-appropriate trajectories for microbiome maturation and bone development and to identify the influence of dietary factors in the process.

PARTICIPANTS

The recruitment started in September 2021 and was completed in February 2023. A total of 1380 subjects were recruited, 690 at birth (group 1) and 690 at 6 months of age (group 2). Groups 1 and 2 will be followed up for 12 months and 36 months, respectively.

FINDINGS TO DATE

The age of the mothers was 31.1±3.7 (mean±SD), and the birth weight of infants was 3.3±0.5 kg with an incidence of caesarean section 50.4%. Food diary information of the first 100 subjects showed that 64 food items were introduced by 6 months. A pilot microbiome analysis revealed that at the species level, bacterial communities were composed of mostly Bacteroides dorei, Bacteroides vulgatus and Escherichia coli, which were consistent with that of previous reports. Feasibility assessments of breast milk vitamin D and human milk oligosaccharides were validated through certified reference measurements. The early data assessment showed a high reliability of the data generated from this study.

FUTURE PLANS

Data collection will be completed in August 2025. Four stage-statistical analyses will be performed as the cohort reaches certain age thresholds before the final report. Analysis of BAMBOO data will be used to develop age-appropriate trajectories for microbiome maturation and bone development for children aged 0-3 years and investigate the contribution of dietary factors in the process.

TRIAL REGISTRATION NUMBER

ChiCTR2100049972.

Evaluation of fecal sample collection methods for feline gut microbiome profiling: fecal loop vs. litter box

Introduction

Microbial population structures within fecal samples are vital for disease screening, diagnosis, and gut microbiome research. The two primary methods for collecting feline fecal samples are: (1) using a fecal loop, which retrieves a rectal sample using a small, looped instrument, and (2) using the litter box, which collects stool directly from the litter. Each method has its own advantages and disadvantages and is suitable for different research objectives.

Methods and results

Whole-genome shotgun metagenomic sequencing were performed on the gut microbiomes of fecal samples collected using these two methods from 10 adult cats housed in the same research facility. We evaluated the influence of collection methods on feline microbiome analysis, particularly their impact on DNA extraction, metagenomic sequencing yield, microbial composition, and diversity in subsequent gut microbiome analyses. Interestingly, fecal sample collection using a fecal loop resulted in a lower yield of microbial DNA compared to the litterbox method (p = 0.004). However, there were no significant differences between the two groups in the proportion of host contamination (p = 0.106), virus contamination (p = 0.232), relative taxonomy abundance of top five phyla (Padj > 0.638), or the number of microbial genes covered (p = 0.770). Furthermore, no significant differences were observed in alpha-diversity, beta-diversity, the number of taxa identified at each taxonomic level, and the relative abundance of taxonomic units.

Discussion

These two sample collection methods do not affect microbial population structures within fecal samples and collecting fecal samples directly from the litterbox within 6 hours after defecation can be considered a reliable approach for microbiome research.

The influence of the gut-brain axis on anxiety and depression: A review of the literature on the use of probiotics

This review aims to argue how using probiotics can improve anxiety and depressive behaviour without adverse effects, also exploring the impact of postbiotics on it. Specifically, probiotics have drawn more attention as effective alternative treatments, considering the rising cost of antidepressant and anti-anxiety drugs and the high risk of side effects. Depression and anxiety disorders are among the most common mental illnesses in the world's population, characterised by low mood, poor general interest, and cognitive or motor dysfunction. Thus, this study analysed published literature on anxiety, depression, and probiotic supplementation from PubMed and Scopus, focusing on the last twenty years. This study focused on the effect of probiotics on mental health as they have drawn more attention because of their extensive clinical applications and positive impact on various diseases. Numerous studies have demonstrated how the gut microbiota might be critical for mood regulation and how probiotics can affect host health by regulating the gut-brain axis. By comparing the different works analysed, it was possible to identify a strategy by which they are selected and employed and, at the same time, to assess how the effect of probiotics can be optimised using postbiotics, an innovation to improve mental well-being in humans.

Effects of xylo-oligosaccharide on gut microbiota, brain protein expression, and lipid profile induced by high-fat diet

Midlife overweight and obesity are risk factors of cognitive decline and Alzheimer' s disease (AD) in late life. In addition to increasing risk of obesity and cognitive dysfunction, diets rich in fats also contributes to an imbalance of gut microbiota. Xylo-oligosaccharides (XOS) are a kind of prebiotic with several biological advantages, and can selectively promote the growth of beneficial microorganisms in the gut. To explore whether XOS can alleviate cognitive decline induced by high-fat diet (HFD) through improving gut microbiota composition, mice were fed with normal control or 60% HFD for 9 weeks to induce obesity. After that, mice were supplemented with XOS (30 g or 60 g/kg-diet) or without, respectively, for 12 weeks. The results showed that XOS inhibited weight gain, decreased epidydimal fat weight, and improved fasting blood sugar and blood lipids in mice. Additionally, XOS elevated spatial learning and memory function, decreased amyloid plaques accumulation, increased brain-derived neurotrophic factor levels, and improved neuroinflammation status in hippocampus. Changes in glycerolipids metabolism-associated lipid compounds caused by HFD in hippocampus were reversed after XOS intervention. On the other hand, after XOS intervention, increase in immune-mediated bacteria, Faecalibacterium was observed. In conclusion, XOS improved gut dysbiosis and ameliorated spatial learning and memory dysfunction caused by HFD by decreasing cognitive decline-associated biomarkers and changing lipid composition in hippocampus.

Update on the gut microbiome in health and diseases

The Human Microbiome Project, Earth Microbiome Project, and next-generation sequencing have advanced novel genome association, host genetic linkages, and pathogen identification. The microbiome is the sum of the microbes, their genetic information, and their ecological niche. This study will describe how millions of bacteria in the gut affect the human body in health and disease. The gut microbiome changes in relation with age, with an increase in Bacteroidetes and Firmicutes. Host and environmental factors affecting the gut microbiome are diet, drugs, age, smoking, exercise, and host genetics. In addition, changes in the gut microbiome may affect the local gut immune system and systemic immune system. In this study, we discuss how the microbiome may affect the metabolism of healthy subjects or may affect the pathogenesis of metabolism-generating metabolic diseases. Due to the high number of publications on the argument, from a methodologically point of view, we decided to select the best papers published in referred journals in the last 3 years. Then we selected the previously published papers. The major goals of our study were to elucidate which microbiome and by which pathways are related to healthy and disease conditions.

Photoaging of biodegradable nanoplastics regulates their toxicity to aquatic insects (Chironomus kiinensis) by impairing gut and disrupting intestinal microbiota

Biodegradable plastic, a widely used ecofriendly alternative to conventional plastic, easily form nanoplastics (NPs) upon environmental weathering. However, the effects and underlying mechanisms governing the toxicity of photoaged biodegradable NPs to aquatic insects are not understood. In this study, we investigated the photoaging of polylactic acid nanoplastics (PLA-NPs, a typical biodegradable plastic) that were placed under xenon arc lamp for 50 days and 100 days and compared the toxicity of virgin and photoaged PLA-NPs to Chironomus kiinensis (a dominant aquatic insect). The results showed that photoaged PLA-NPs significantly decreased the body weight, body length and emergence rate of C. kiinensis. Additionally, photoaged PLA-NPs induced more severe gut oxidative stress, histological damage, and inflammatory responses than virgin PLA-NPs. Furthermore, the alpha diversity of gut microbiota was lower in photoaged PLA-NPs group than virgin PLA-NPs. The relative abundance of key gut bacteria related to intestinal barrier defense, immunity, and nutrient absorption was reduced more significantly in photoaged PLA-NPs group than virgin PLA, indirectly leading to stronger gut damage and growth reduction. A stronger impact of photoaged PLA-NPs on the gut and its microbiota occurred because photoaging reduced the size of NPs from 255.5 nm (virgin PLA) to 217.1 nm (PLA-50) and 182.5 nm (PLA-100), induced surface oxidation and enhancement of oxidative potential, and improved the stability of NPs, thereby exacerbating toxicity on the gut and its microbiota. This study provides insights into the effects of biodegradable NPs on aquatic insects and highlights the importance of considering biodegradable nanoplastic aging in risk assessments.

Nanoplastics Affect the Bioaccumulation and Gut Toxicity of Emerging Perfluoroalkyl Acid Alternatives to Aquatic Insects (Chironomus kiinensis): Importance of Plastic Surface Charge

Persistent organic pollutants (POPs) have been widely suggested as contributors to the aquatic insect biomass decline, and their bioavailability is affected by engineered particles. However, the toxicity effects of emerging ionizable POPs mediated by differentially charged engineered nanoparticles on aquatic insects are unknown. In this study, 6:2 chlorinated polyfluoroalkyl ether sulfonate (F-53B, an emerging perfluoroalkyl acid alternative) was selected as a model emerging ionizable POP; the effect of differentially charged nanoplastics (NPs, 50 nm, 0.5 g/kg) on F-53B bioaccumulation and gut toxicity to Chironomus kiinensis were investigated through histopathology, biochemical index, and gut microbiota analysis. The results showed that when the dissolved concentration of F-53B remained constant, the presence of NPs enhanced the adverse effects on larval growth, emergence, gut oxidative stress and inflammation induced by F-53B, and the enhancement caused by positively charged NP-associated F-53B was stronger than that caused by the negatively charged one. This was mainly because positively charged NPs, due to their greater adsorption capacity and higher bioavailable fraction of associated F-53B, increased the bioaccumulation of F-53B in larvae more significantly than negatively charged NPs. In addition, positively charged NPs interact more easily with gut biomembranes and microbes with a negative charge, further increasing the probability of F-53B interacting with gut biomembranes and microbiota and thereby aggravating gut damage and key microbial dysbacteriosis related to gut health. These findings demonstrate that the surface charge of NPs can regulate the bioaccumulation and toxicity of ionizable POPs to aquatic insects.

Coping with extremes: Alternations in diet, gut microbiota, and hepatic metabolic functions in a highland passerine

In wild animals, diet and gut microbiota interactions are critical moderators of metabolic functions and are highly contingent on habitat conditions. Challenged by the extreme conditions of high-altitude environments, the strategies implemented by highland animals to adjust their diet and gut microbial composition and modulate their metabolic substrates remain largely unexplored. By employing a typical human commensal species, the Eurasian tree sparrow (Passer montanus, ETS), as a model species, we studied the differences in diet, digestive tract morphology and enzyme activity, gut microbiota, and metabolic energy profiling between highland (the Qinghai-Tibet Plateau, QTP; 3230 m) and lowland (Shijiazhuang, Hebei; 80 m) populations. Our results showed that highland ETSs had enlarged digestive organs and longer small intestinal villi, while no differences in key digestive enzyme activities were observed between the two populations. The 18S rRNA sequencing results revealed that the dietary composition of highland ETSs were more animal-based and less plant-based than those of the lowland ones. Furthermore, 16S rRNA sequencing results suggested that the intestinal microbial communities were structurally segregated between populations. PICRUSt metagenome predictions further indicated that the expression patterns of microbial genes involved in material and energy metabolism, immune system and infection, and xenobiotic biodegradation were strikingly different between the two populations. Analysis of liver metabolomics revealed significant metabolic differences between highland and lowland ETSs in terms of substrate utilization, as well as distinct sex-specific alterations in glycerophospholipids. Furthermore, the interplay between diet, liver metabolism, and gut microbiota suggests a dietary shift resulting in corresponding changes in gut microbiota and metabolic functions. Our findings indicate that highland ETSs have evolved to optimize digestion and absorption, rely on more protein-rich foods, and possess gut microbiota tailored to their dietary composition, likely adaptive physiological and ecological strategies adopted to cope with extreme highland environments.

Bile Microbiome Signatures Associated with Pancreatic Ductal Adenocarcinoma Compared to Benign Disease: A UK Pilot Study

Pancreatic ductal adenocarcinoma (PDAC) has a very poor survival. The intra-tumoural microbiome can influence pancreatic tumourigenesis and chemoresistance and, therefore, patient survival. The role played by bile microbiota in PDAC is unknown. We aimed to define bile microbiome signatures that can effectively distinguish malignant from benign tumours in patients presenting with obstructive jaundice caused by benign and malignant pancreaticobiliary disease. Prospective bile samples were obtained from 31 patients who underwent either Endoscopic Retrograde Cholangiopancreatography (ERCP) or Percutaneous Transhepatic Cholangiogram (PTC). Variable regions (V3-V4) of the 16S rRNA genes of microorganisms present in the samples were amplified by Polymerase Chain Reaction (PCR) and sequenced. The cohort consisted of 12 PDAC, 10 choledocholithiasis, seven gallstone pancreatitis and two primary sclerosing cholangitis patients. Using the 16S rRNA method, we identified a total of 135 genera from 29 individuals (12 PDAC and 17 benign). The bile microbial beta diversity significantly differed between patients with PDAC vs. benign disease (Permanova p = 0.0173). The separation of PDAC from benign samples is clearly seen through unsupervised clustering of Aitchison distance. We found three genera to be of significantly lower abundance among PDAC samples vs. benign, adjusting for false discovery rate (FDR). These were Escherichia (FDR = 0.002) and two unclassified genera, one from Proteobacteria (FDR = 0.002) and one from Enterobacteriaceae (FDR = 0.011). In the same samples, the genus Streptococcus (FDR = 0.033) was found to be of increased abundance in the PDAC group. We show that patients with obstructive jaundice caused by PDAC have an altered microbiome composition in the bile compared to those with benign disease. These bile-based microbes could be developed into potential diagnostic and prognostic biomarkers for PDAC and warrant further investigation.

Exploring Gut Microbiota and the Influence of Physical Activity Interventions on Overweight and Obese Children and Adolescents: A Systematic Review

The recognition that the gut microbiota of obese children differs from lean children has grown, and some studies suggest that physical activity positively influences the gut microbiota. This systematic review explores the changes in the gut microbiota composition of obese and non-obese children and adolescents and provides an understanding of the effects of physical activity interventions in modulating their microbiota. The PRISMA protocol was used across PubMed, Scopus, and Web of Science. Overall, twenty-four research papers were included in accordance with the chosen inclusion and exclusion criteria, eighteen studies compared the gut microbiota of obese and normal-weight children and adolescents, and six studies explored the effect of physical activity interventions on the gut microbiota. The analysis indicated that obese gut microbiota is reduced in Bacteroidetes, Bifidobacterium and alpha diversity but enriched in Proteobacteria and Lactobacillus. Interventions with physical activity seem to improve the alpha diversity and beneficial bacteria linked to body weight loss in children and adolescents. The gut microbiota of obese children exhibited a remarkably individual variation. More interventions are needed to clearly and accurately explore the relationships between child obesity, gut microbiota, and physical activity and to develop approaches to decrease the incidence of paediatric obesity.

Bioelectrical State of Bacteria Is Linked to Growth Dynamics and Response to Neurotransmitters: Perspectives for the Investigation of the Microbiota-Brain Axis

Inter-cellular communication is mediated by a sum of biochemical, biophysical, and bioelectrical signals. This might occur not only between cells belonging to the same tissue and/or animal species but also between cells that are, from an evolutionary point of view, far away. The possibility that bioelectrical communication takes place between bacteria and nerve cells has opened exciting perspectives in the study of the gut microbiota-brain axis. The aim of this paper is (i) to establish a reliable method for the assessment of the bioelectrical state of two bacterial strains: Bacillus subtilis (B. subtilis) and Limosilactobacillus reuteri (L. reuteri); (ii) to monitor the bacterial bioelectrical profile throughout its growth dynamics; and (iii) to evaluate the effects of two neurotransmitters (glutamate and γ-aminobutyric acid-GABA) on the bioelectrical signature of bacteria. Our results show that membrane potential (Vmem) and the proliferative capacity of the population are functionally linked in B. subtilis in each phase of the cell cycle. Remarkably, we demonstrate that bacteria respond to neural signals by changing Vmem properties. Finally, we show that Vmem changes in response to neural stimuli are present also in a microbiota-related strain L. reuteri. Our proof-of-principle data reveal a new methodological approach for the better understanding of the relation between bacteria and the brain, with a special focus on gut microbiota. Likewise, this approach will open exciting perspectives in the study of the inter-cellular mechanisms which regulate the bi-directional communication between bacteria and neurons and, ultimately, for designing gut microbiota-brain axis-targeted treatments for neuropsychiatric diseases.

Questionnaire-based analysis of autism spectrum disorders and gastrointestinal symptoms in children and adolescents: a systematic review and meta-analysis

Background

Gastrointestinal (GI) symptoms are frequently experienced by children with autism spectrum disorder (ASD), and these symptoms cause difficulties for these children and their families. However, studies of GI symptom prevalence differ significantly. This meta-analysis aimed to analyze the prevalence of GI symptoms in children with ASD.

Methods and findings

PubMed, Scopus, Web of Science, EMBASE were electronically searched to collect all literature on gastrointestinal symptoms of children with ASD collected through questionnaires or scales from January 2012 to May 2021. Four researchers independently scanned the literature and extracted information on general characteristics. First author name, year of publication, geographical location, type of study, sample sizes of ASD and control (if any) children, sex and average age, number of GI cases, number of GI symptoms, GI assessment tools (gastrointestinal symptoms scale), autism diagnosis methods, and other necessary data were collected and analyzed using Stata V16. The questionnaires included the Rome, 6-GSI, GIQ, GSRS, GSIQ, ADI-R, PedsQL-GI, parent-report, GI-related, and self-administered questionnaires. Compared with typically developing (TD) children, the odds ratio for In children with ASD with at least one GI symptom was 3.64, and the total prevalence was 55%. The cumulative prevalence rates of various symptoms were summarized, showing that 37% of children with ASD had constipation, 21% had abdominal pain, 19% had diarrhea, 8% had vomiting, and 23% had abdominal distension.

Conclusions

The results of this meta-analysis on GI symptoms in ASD show that patients with ASD are more likely to develop symptoms than TD children. The prevalence of GI symptoms in In children with ASD was 55%.

Systematic Review Registration

www.crd.york.ac.uk/PROSPERO, identifier, #CRD42017080579.

Effects of urbanization and lifestyle habits on the intestinal microbiota of adolescents in eastern China

Introduction

Owing to urbanization, living habits have changed widely, leading to alterations in the intestinal microbiota of urban residents. However, there are few studies on the characteristics of intestinal microbiota of adolescents living in different urbanized areas in China.

Methods

A total of 302 fecal samples collected from adolescent students in eastern China were examined. 16S rRNA high-throughput sequencing was used to identify the fecal microbiota. These data were combined with questionnaire survey results to investigate the effect of urbanization on the intestinal microbiota of adolescents in eastern China. Moreover, the role of lifestyle habits in this relationship was also evaluated.

Results

The results revealed significant differences in the structure of the intestinal microbiota among adolescents living in regions with different levels of urbanization. Adolescents living in urban regions had a significantly higher proportion of Bacteroides (p <  0.001, FDR = 0.004), whereas those living in towns and rural regions had higher proportions of Bifidobacterium (p < 0.001, FDR < 0.001) and Prevotella (p  < 0.05, FDR = 0.019). The diversity of the intestinal microbiota was higher in urban residents than in adolescents living in towns and rural regions (p  <  0.05). In addition, the differences in intestinal microbiota across individuals living in cities, towns, and rural regions were related to dietary preferences, flavor preferences, and sleep and exercise durations. Adolescents who ate more meat had more Dorea (LDA = 3.622, p = 0.04), while the abundance of Escherichia-Shigella is higher among adolescents who ate more condiments (LDA = 4.285, p = 0.02). The abundance of Dialister was significantly increased in adolescents with longer sleep durations (LDA = 4.066, p = 0.03). Adolescents who exercised for a long duration had more Faecalibacterium than those who exercised for a shorter duration (LDA = 4.303, p = 0.04).

Discussion

Our research has preliminarily demonstrated that there were differences in the composition of Gut microbiome in stool samples of adolescents living in different urbanized areas, and provide a scientific basis for the maintenance of a healthy intentional microbota in adolescences.

Current progress and challenges of immunotherapy in gastric cancer: A focus on CAR-T cells therapeutic approach

Gastric cancer (GC) is a severe malignancy, accounting for the third most common cancer death worldwide. Despite the development of chemo-radiation therapy, there has not been sufficient survival advantage in patients with GC who were treated by these methods. GC immunogenicity is hampered by a highly immunosuppressive microenvironment; therefore, further understanding of the molecular biology of GC is the potential to achieve new therapeutic strategies in GC therapy, including specific immunotherapy. Current immunotherapies are mainly based on cytokines, immune checkpoints, monoclonal antibodies (mAb), bispecific antibodies (BisAbs), antibody-drug conjugates (ADCs), and chimeric antigen receptor (CAR). Immunotherapy has made significant progress in the treatment of GC, so that studies show that nivolumab as a programmed death 1 (PD1) inhibitor has proper safety and effectiveness as a third-line treatment for GC patients. Multiple monoclonal antibodies like ramucirumab and claudiximab were effective in treating GC patients, especially in combination with other treatments. Despite the challenges of CAR therapy in solid tumors, CAR therapy targets various GC cells targets; among them, intercellular adhesion molecule (ICAM)-1 CAR-T cell and CLDN18.2 CAR-T cell have shown promising results. Although responses to all these treatments are encouraging and in some cases, durable, these successes are not seen in all treated patients. The present review represents the development of various immunotherapies especially CAR-T cell therapy, its current use, clinical data in GC, and their limitations.

Omega-3 polyunsaturated fatty acids ameliorate PM2.5 exposure induced lung injury in mice through remodeling the gut microbiota and modulating the lung metabolism

Short-term or long-term exposure to fine particulate matter (PM2.5) is related to increased incidences of respiratory diseases. This study aimed to investigate the influences of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) supplementation on oxidative stress, inflammation, lung metabolic profile, and gut microbiota in PM2.5-induced lung injury mice. Mice were divided into four groups (n = 15, per group): two unsupplemented groups, control group and PM2.5 group, and two supplemented groups with ω-3 PUFAs, ω-3 PUFAs group, and ω-3 PUFAs + PM2.5 group. Mice in the supplemented groups were placed on an ω-3 PUFAs-enriched diet (ω-3 PUFAs, 21 g/kg). During the 5th to 6th week of dietary supplementation, mice were exposed to PM2.5 by intra-tracheal instillation. ω-3 PUFAs ameliorate lung histopathological injury, reduce inflammatory responses and oxidative stress, affect lung metabolite profile, and modulate gut microbiota in PM2.5-induced lung injury mice. Thus, supplementary ω-3 PUFAs showed effectiveness in attenuation of PM2.5-induced lung injury, indicating that the interventions exhibited preventive and therapeutic potential.

Periodontal treatment and microbiome-targeted therapy in management of periodontitis-related nonalcoholic fatty liver disease with oral and gut dysbiosis

A growing body of evidence from multiple areas proposes that periodontal disease, accompanied by oral inflammation and pathological changes in the microbiome, induces gut dysbiosis and is involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). A subgroup of NAFLD patients have a severely progressive form, namely nonalcoholic steatohepatitis (NASH), which is characterized by histological findings that include inflammatory cell infiltration and fibrosis. NASH has a high risk of further progression to cirrhosis and hepatocellular carcinoma. The oral microbiota may serve as an endogenous reservoir for gut microbiota, and transport of oral bacteria through the gastro-intestinal tract can set up a gut microbiome dysbiosis. Gut dysbiosis increases the production of potential hepatotoxins, including lipopolysaccharide, ethanol, and other volatile organic compounds such as acetone, phenol and cyclopentane. Moreover, gut dysbiosis increases intestinal permeability by disrupting tight junctions in the intestinal wall, leading to enhanced translocation of these hepatotoxins and enteric bacteria into the liver through the portal circulation. In particular, many animal studies support that oral administration of Porphyromonas gingivalis, a typical periodontopathic bacterium, induces disturbances in glycolipid metabolism and inflammation in the liver with gut dysbiosis. NAFLD, also known as the hepatic phenotype of metabolic syndrome, is strongly associated with metabolic complications, such as obesity and diabetes. Periodontal disease also has a bidirectional relationship with metabolic syndrome, and both diseases may induce oral and gut microbiome dysbiosis with insulin resistance and systemic chronic inflammation cooperatively. In this review, we will describe the link between periodontal disease and NAFLD with a focus on basic, epidemiological, and clinical studies, and discuss potential mechanisms linking the two diseases and possible therapeutic approaches focused on the microbiome. In conclusion, it is presumed that the pathogenesis of NAFLD involves a complex crosstalk between periodontal disease, gut microbiota, and metabolic syndrome. Thus, the conventional periodontal treatment and novel microbiome-targeted therapies that include probiotics, prebiotics and bacteriocins would hold great promise for preventing the onset and progression of NAFLD and subsequent complications in patients with periodontal disease.

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

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

Fasting and refeeding triggers specific changes in bile acid profiles and gut microbiota

BACKGROUND

Bile acids (BAs) are closely related to nutrient supply and modified by gut microbiota. Gut microbiota perturbations shape BA composition, which further affects host metabolism.

METHODS

We investigated BA profiles in plasma, feces, and liver of mice fed ad libitum, fasted for 24 h, fasted for 24 h and then refed for 24 h using ultraperformance liquid chromatography coupled to tandem mass spectrometry. Gut microbiota was measured by 16S rRNA gene sequencing. Expressions of BA biosynthesis-related genes in the liver and BA reabsorption-related genes in the ileum were analyzed.

FINDINGS

Compared with the controls, unconjugated primary BAs (PBAs) and unconjugated secondary BAs (SBAs) in plasma were decreased whereas conjugated SBAs in plasma, unconjugated PBAs, unconjugated SBAs and conjugated SBAs in feces, and unconjugated SBAs in liver were increased in the fasting mice. The expression of BA biosynthesis-related genes in the liver and BA reabsorption-related genes in the ileum were decreased in the fasting mice compared with the controls. Compared with the controls, Akkermansia, Parabacteroides, Muribaculum, Eubacterium_coprostanoligenes and Muribaculaceae were increased in the fasting mice whereas Lactobacillus and Bifidobacterium were decreased. All these changes in BAs and gut microbiota were recovered under refeeding. Akkermansia was negatively correlated with plasma levels of unconjugated PBAs, unconjugated SBAs and glucose, whereas it was positively correlated with plasma conjugated SBAs, fecal unconjugated PBAs, and fecal unconjugated SBAs.

CONCLUSIONS

We characterized the BA profiles, gut microbiota, and gene expression responsible for BA biosynthesis and intestinal reabsorption to explore their rapid changes in response to food availability. Our study highlighted the rapid effect of nutrient supply on BAs and gut microbiota.

The metabolic syndrome and its components as prognostic factors in colorectal cancer: A meta-analysis and systematic review

BACKGROUND AND AIM

Metabolic syndrome (MetS) increases the risk of colorectal cancer (CRC), and the impact of MetS on CRC prognosis remains controversial after the diagnosis of CRC has been established. This study aimed to explore the impact of the individual components and synergies of MetS on the prognosis of patients with CRC.

METHODS

We searched articles published before August 3, 2022, in four databases, including PubMed, Embase, Cochrane Library, and ScienceDirect. The random-effects model inverse variance method was used to estimate the summarized effect size.

RESULTS

Patients with CRC with MetS were 1.342 times more likely to experience all-cause mortality than those without MetS, and the 95% confidence interval (CI) of hazard ratio (HR) was 1.107-1.627 (P = 0.003). CRC-specific mortality in patients with CRC with MetS was 2.122 times higher than in those without MetS, and the 95% CI of HR was 1.080-4.173 (P = 0.029). CRC-specific mortality exhibited an increasing trend of risk with increased metabolic risk factors. The HR of CRC-specific mortality for one, two, and three metabolic risk factors was 1.206 (95% CI, 1.034-1.407; P = 0.017), 1.881 (95% CI, 1.253-2.824; P = 0.002), and 2.327 (95% CI, 1.262-4.291; P = 0.007), respectively.

CONCLUSIONS

Metabolic syndrome increased all-cause and CRC-specific mortality in patients with CRC. As a single component of MetS, diabetes mellitus increased overall mortality in patients with CRC, while obesity increased CRC-specific mortality in patients with CRC, with a significant difference from non-MetS. Moreover, the risk of CRC-specific mortality increased with increasing number of metabolic risk factors.

Plant-based diets in gastrointestinal diseases: Which evidence?

Plant-based diets (PBDs), rich in high-quality plant foods, offer multiple benefits for the overall and gastrointestinal health. Recently, it has been demostrated that the positive effects of PBDs on gastrointestinal health can be mediated by the gut microbiota, in particular, by inducing a greater diversity of bacteria. This review summarizes current knowledge on the relationship between nutrition, the gut microbiota, and host metabolic status. We discussed how dietary habits modify the composition and physiological activity of the gut microbiota and how gut dysbiosis affects the most prevalent gastrointestinal diseases, including inflammatory bowel diseases, functional bowel disorders, liver disorders, and gastrointestinal cancer. The beneficial role of PBDs is being increasingly recognized as potentially useful in the management of most diseases of the gastrointestinal tract.

Leaky Gut and the Ingredients That Help Treat It: A Review

The human body is in daily contact with potentially toxic and infectious substances in the gastrointestinal tract (GIT). The GIT has the most significant load of antigens. The GIT can protect the intestinal integrity by allowing the passage of beneficial agents and blocking the path of harmful substances. Under normal conditions, a healthy intestinal barrier prevents toxic elements from entering the blood stream. However, factors such as stress, an unhealthy diet, excessive alcohol, antibiotics, and drug consumption can compromise the composition of the intestinal microbiota and the homeostasis of the intestinal barrier function of the intestine, leading to increased intestinal permeability. Intestinal hyperpermeability can allow the entry of harmful agents through the junctions of the intestinal epithelium, which pass into the bloodstream and affect various organs and systems. Thus, leaky gut syndrome and intestinal barrier dysfunction are associated with intestinal diseases, such as inflammatory bowel disease and irritable bowel syndrome, as well as extra-intestinal diseases, including heart diseases, obesity, type 1 diabetes mellitus, and celiac disease. Given the relationship between intestinal permeability and numerous conditions, it is convenient to seek an excellent strategy to avoid or reduce the increase in intestinal permeability. The impact of dietary nutrients on barrier function can be crucial for designing new strategies for patients with the pathogenesis of leaky gut-related diseases associated with epithelial barrier dysfunctions. In this review article, the role of functional ingredients is suggested as mediators of leaky gut-related disorders.

Alterations of the gut microbiota in type 2 diabetics with or without subclinical hypothyroidism

Background

Diabetes and thyroid dysfunction are two closely related endocrine diseases. Increasing evidences show that gut microbiota plays an important role in both glucose metabolism and thyroid homeostasis. Meanwhile, copy number variation (CNV) of host salivary α-amylase gene (AMY1) has been shown to correlate with glucose homeostasis. Hence, we aim to characterize the gut microbiota and CNV of AMY1 in type 2 diabetes (T2D) patients with or without subclinical hypothyroidism (SCH).

Methods

High-throughput sequencing was used to analyze the gut microbiota of euthyroid T2D patients, T2D patients with SCH and healthy controls. Highly sensitive droplet digital PCR was used to measure AMY1 CN.

Results

Our results revealed that T2D patients have lower gut microbial diversity, no matter with or without SCH. The characteristic taxa of T2D patients were Coriobacteriales, Coriobacteriaceae, Peptostreptococcaceae, Pseudomonadaceae, Collinsella, Pseudomonas and Romboutsia. Meanwhile, Escherichia/Shigella, Lactobacillus_Oris, Parabacteroides Distasonis_ATCC_8503, Acetanaerobacterium, Lactonifactor, uncultured bacterium of Acetanaerobacterium were enriched in T2D patients with SCH. Moreover, serum levels of free triiodothyronine (FT3) and free thyroxine (FT4) in T2D patients were both negatively correlated with richness of gut microbiota. A number of specific taxa were also associated with clinical parameters at the phylum and genus level. In contrast, no correlation was found between AMY1 CN and T2D or T2D_SCH.

Conclusion

This study identified characteristic bacterial taxa in gut microbiota of T2D patients with or without SCH, as well as the taxa associated with clinical indices in T2D patients. These results might be exploited in the prevention, diagnosis and treatment of endocrine disorders in the future.

Native microbiomes in danger: Could One Health help to cope with this threat to global health?

Planetary health faces an emergency associated with global change. Climate change, the increase in world population and urban concentration, the hyperintensification of productive systems, and the associated changes in land use, among other factors, are generating a risky substrate for global health deterioration. The emergence of the coronavirus disease 2019 pandemic is an example of the problems that this situation can provoke. Several researchers and health professionals have addressed the role of microorganisms, particularly bacteria, in promoting global health, mainly in the past decades. However, global changes have contributed to the extinction of a wide array of bacterial species and the disruption of microbial communities that support the homeostasis of humans, animals, and the environment. The need to protect the diversity and richness of native microbiomes in biotic and abiotic environments is crucial but has been frequently underestimated. The "One Health" approach, based on integrating traditionally unconnected fields such as human, animal, and environmental health, could provide a helpful framework to face this challenge. Anyway, drastic political decisions will be needed to tackle this global health crisis, in which the preservation of native microbial resources plays a critical role, even in preventing the risk of a new pandemic. This review aims to explain the importance of native microbiomes in biotic and abiotic ecosystems and the need to consider bacterial extinction as a crucial problem that could be addressed under a One Health approach.

Influence of Sex on the Microbiota of the Human Face

The role of the microbiota in health and disease has long been recognized and, so far, the cutaneous microbiota in humans has been widely investigated. The research regarded mainly the microbiota variations between body districts and disease skin states (i.e., atopic dermatitis, psoriasis, acne). In fact, relatively little information is available about the composition of the healthy skin microbiota. The cosmetic industry is especially interested in developing products that maintain and/or improve a healthy skin microbiota. Therefore, in the present work, the authors chose to investigate in detail the structure and composition of the basal bacterial community of the face. Ninety-six cheek samples (48 women and 48 men) were collected in the same season and the same location in central northern Italy. Bacterial DNA was extracted, the 16S rDNA gene was amplified by PCR, the obtained amplicons were subjected to next generation sequencing. The principal members of the community were identified at the genus level, and statistical analyses showed significant variations between the two sexes. This study identified abundant members of the facial skin microbiota that were rarely reported before in the literature and demonstrated the differences between male and female microbiota in terms of both community structure and composition.

The effect of “moderately restricted carbohydrate” diet on gut microbiota composition and metabolic parameters in women with metabolic syndrome: a study protocol for a randomized controlled trial

Background

Metabolic syndrome (MetS) is a group of risk factors that increase the risk of death and a variety of chronic diseases. Recent studies have indicated that the imbalance of gut microbiota might contribute to development and progression of metabolic syndrome. Carbohydrate restriction in the diet has been proven to be one of the most effective methods in the management of metabolic syndrome, even in the absence of weight loss. However, no study has examined the effects of a carbohydrate-restricted diet on gut microbiota composition in metabolic syndrome patients. Thus, we will examine the effects of a “moderately restricted carbohydrate (MRC)” diet on gut microbiota, insulin resistance, and components of MetS among Iranian women. In addition, the stability of changes in dependent variables, including gut microbiota, will also be assessed.

Methods

This is a parallel randomized clinical trial in which 70 overweight or obese women aged 20–50 years with MetS will be randomly assigned to receive either MRC diet (42–45% carbohydrate, 35–40% fats) or a normal weight loss (NWL) diet (52–55% carbohydrate, 25–30% fats) for 3 months. Protein accounted for 15–17% of total energy in both diets. The quantity of gut microbiota including Firmicutes, Bacteroidetes, Bifidobacteria, Lactobacillus, Clostridium, Prevotella, Bacteroidetes, and Akkermansia muciniphila, as well as anthropometric, blood pressure, and metabolic parameters will be measured at study baseline and the end of trail. At the end of this phase, all participants will be placed on a weight maintenance diet for an additional 6 months. After following up study subjects in this duration, all dependent variables will be examined again to assess their stability over this period.

Discussion

To the best of our knowledge, this is the first randomized controlled trial investigating the effects of a moderately restricted carbohydrate diet on gut microbiota composition and several metabolic parameters during the weight loss and maintenance phases in women with MetS.

Trial registration

Iranian Registry of Clinical Trials (www.irct.ir, IRCT20210307050621N1). Registered on May 31, 2021.

Fecal Microbiota Transplantation as New Therapeutic Avenue for Human Diseases

The human body is home to a variety of micro-organisms. Most of these microbial communities reside in the gut and are referred to as gut microbiota. Over the last decades, compelling evidence showed that a number of human pathologies are associated with microbiota dysbiosis, thereby suggesting that the reinstatement of physiological microflora balance and composition might ameliorate the clinical symptoms. Among possible microbiota-targeted interventions, pre/pro-biotics supplementations were shown to provide effective results, but the main limitation remains in the limited microbial species available as probiotics. Differently, fecal microbiota transplantation involves the transplantation of a solution of fecal matter from a donor into the intestinal tract of a recipient in order to directly change the recipient's gut microbial composition aiming to confer a health benefit. Firstly used in the 4th century in traditional Chinese medicine, nowadays, it has been exploited so far to treat recurrent Clostridioides difficile infections, but accumulating data coming from a number of clinical trials clearly indicate that fecal microbiota transplantation may also carry the therapeutic potential for a number of other conditions ranging from gastrointestinal to liver diseases, from cancer to inflammatory, infectious, autoimmune diseases and brain disorders, obesity, and metabolic syndrome. In this review, we will summarize the commonly used preparation and delivery methods, comprehensively review the evidence obtained in clinical trials in different human conditions and discuss the variability in the results and the pivotal importance of donor selection. The final aim is to stimulate discussion and open new therapeutic perspectives among experts in the use of fecal microbiota transplantation not only in Clostridioides difficile infection but as one of the first strategies to be used to ameliorate a number of human conditions.

Metabolic Synergy between Human Symbionts Bacteroides and Methanobrevibacter

Trophic interactions between microbes are postulated to determine whether a host microbiome is healthy or causes predisposition to disease. Two abundant taxa, the Gram-negative heterotrophic bacterium Bacteroides thetaiotaomicron and the methanogenic archaeon Methanobrevibacter smithii, are proposed to have a synergistic metabolic relationship. Both organisms play vital roles in human gut health; B. thetaiotaomicron assists the host by fermenting dietary polysaccharides, whereas M. smithii consumes end-stage fermentation products and is hypothesized to relieve feedback inhibition of upstream microbes such as B. thetaiotaomicron. To study their metabolic interactions, we defined and optimized a coculture system and used software testing techniques to analyze growth under a range of conditions representing the nutrient environment of the host. We verify that B. thetaiotaomicron fermentation products are sufficient for M. smithii growth and that accumulation of fermentation products alters secretion of metabolites by B. thetaiotaomicron to benefit M. smithii. Studies suggest that B. thetaiotaomicron metabolic efficiency is greater in the absence of fermentation products or in the presence of M. smithii. Under certain conditions, B. thetaiotaomicron and M. smithii form interspecies granules consistent with behavior observed for syntrophic partnerships between microbes in soil or sediment enrichments and anaerobic digesters. Furthermore, when vitamin B12, hematin, and hydrogen gas are abundant, coculture growth is greater than the sum of growth observed for monocultures, suggesting that both organisms benefit from a synergistic mutual metabolic relationship. IMPORTANCE The human gut functions through a complex system of interactions between the host human tissue and the microbes which inhabit it. These diverse interactions are difficult to model or examine under controlled laboratory conditions. We studied the interactions between two dominant human gut microbes, B. thetaiotaomicron and M. smithii, using a seven-component culturing approach that allows the systematic examination of the metabolic complexity of this binary microbial system. By combining high-throughput methods with machine learning techniques, we were able to investigate the interactions between two dominant genera of the gut microbiome in a wide variety of environmental conditions. Our approach can be broadly applied to studying microbial interactions and may be extended to evaluate and curate computational metabolic models. The software tools developed for this study are available as user-friendly tutorials in the Department of Energy KBase.

Integrative multiomics analysis reveals host-microbe-metabolite interplays associated with the aging process in Singaporeans

The age-associated alterations in microbiomes vary across populations due to the influence of genetics and lifestyles. To the best of our knowledge, the microbial changes associated with aging have not yet been investigated in Singapore adults. We conducted shotgun metagenomic sequencing of fecal and saliva samples, as well as fecal metabolomics to characterize the gut and oral microbial communities of 62 healthy adult male Singaporeans, including 32 young subjects (age, 23.1 ± 1.4 years) and 30 elderly subjects (age, 69.0 ± 3.5 years). We identified 8 gut and 13 oral species that were differentially abundant in elderly compared to young subjects. By combining the gut and oral microbiomes, 25 age-associated oral-gut species connections were identified. Moreover, oral bacteria Acidaminococcus intestine and Flavonifractor plautii were less prevalent/abundant in elderly gut samples than in young gut samples, whereas Collinsella aerofaciens and Roseburia hominis showed the opposite trends. These results indicate the varied gut-oral communications with aging. Subsequently, we expanded the association studies on microbiome, metabolome and host phenotypic parameters. In particular, Eubacterium eligens increased in elderly compared to young subjects, and was positively correlated with triglycerides, which implies that the potential role of E. eligens in lipid metabolism is altered during the aging process. Our results demonstrated aging-associated changes in the gut and oral microbiomes, as well as the connections between metabolites and host-microbe interactions, thereby deepening the understanding of alterations in the human microbiome during the aging process in a Singapore population.

Role of Gastric Microorganisms Other than Helicobacter pylori in the Development and Treatment of Gastric Diseases

The microenvironment in the stomach is different from other digestive tracts, mainly because of the secretion of gastric acid and digestive enzymes, bile reflux, special mucus barrier, gastric peristalsis, and so on, which all contribute to the formation of antibacterial environment. Microecological disorders can lead to gastric immune disorders or lead to the decrease of dominant bacteria and the increase of the abundance and virulence of pathogenic microorganisms and then promote the occurrence of diseases. The body performs its immune function through innate and adaptive immunity and maintains microbial balance through the mechanism of immune homeostasis. Microecological imbalance can lead to the invasion of pathogenic microorganisms and damage mucosal barrier and immune system. The coexistence of gastric microorganisms (including viruses and fungi) may play a synergistic or antagonistic role in the pathogenesis of gastric diseases. Probiotics have the ability to compete with intestinal pathogens, increase the secretion of immunoglobulin A (IgA), stimulate the production of mucin, bacteriocin, and lactic acid, regulate the expression and secretion of cytokines, and regulate the growth of microbiota, which all have beneficial effects on the host microbial environment. At present, most studies focused on Helicobacter pylori, ignoring other stomach microbes and the overall stomach microecology. So, in this article, we reviewed advances in human gastric microecology, the relationship between gastric microecology and immunity or gastric diseases, and the treatment of probiotics in gastric diseases, in order to explore new area for further study of gastric microorganisms and treatment of gastric diseases.

Association of triclosan and triclocarban in urine with obesity risk in Chinese school children

BACKGROUND

Laboratory studies have suggested that triclosan and triclocarban can influence energy metabolism by multiple mechanisms and are potential obesogens, but the effect on obesity risk has not been well investigated in human.

OBJECTIVE

To examine the associations of triclosan and triclocarban in urine with childhood obesity.

METHODS

We investigated 458 school children aged 7-11 years who entered a dynamic cohort of children established in Shanghai in 2019 and 2020. Triclosan and triclocarban were determined in first morning urine by liquid chromatography coupled to mass spectrometry. Body mass index (BMI) and waist circumference (WC) were used to identify general overweight/obesity and central obesity, respectively. Logistic regression and linear models of generalized estimating equations (GEE) were used to investigate the association between urinary triclosan and triclocarban with obesity prevalence.

RESULTS

After adjusting for potential confounders, children with detectable triclocarban in urine had a higher proportion of general overweight/obesity (odds ratio (OR): 1.84; 95% confidential interval (95% CI): 1.19, 2.85) or central obesity (OR: 1.71; 95% CI: 1.03, 2.84). Compared to the low tertile, children in the median tertile of triclosan showed a higher proportion of central obesity (OR: 1.78; 95 %CI: 0.98, 3.24) and children in the high tertile of triclocarban had a higher proportion of general overweight/obesity (OR: 2.25; 95 %CI: 1.31, 3.88) and central obesity (OR: 2.08; 95 %CI: 1.12, 3.87). When the tertiles of triclocarban in urine were treated as a continuous variable, a positive exposure-response relationship was found with general overweight/obesity (OR: 1.50; 95 %CI: 1.15, 1.96) and central obesity (OR: 1.44; 95 %CI: 1.06, 1.95). Multiple linear regression showed a positive exposure-response relationship between triclocarban and BMI (β: 0.45; 95 %CI: 0.11, 0.80) values.

CONCLUSION

Exposure to triclosan and triclocarban was associated with increased risk of childhood obesity. Given the cross-sectional design, more studies are needed to interrogate these findings.

Impact of type 1 diabetes on the composition and functional potential of gut microbiome in children and adolescents: possible mechanisms, current knowledge, and challenges

Diabetes prevalence and incidence among youth have been increasing globally. Type 1 Diabetes (T1D) in children or adolescents accounts for 5-10% of all diagnosed cases of diabetes. Emerging evidence indicates that genetic factors, especially genes in the human leukocyte antigen region, are not the only factors involved in the predisposition of an individual to T1D. The pathogenesis and development of T1D is driven by both genetic predisposition and environmental factors. Studies indicate that gut microbiota is one of the potential environmental influencers involved in the pathophysiology of TID. Gut microbiota mediates the development of diabetes by altering intestinal permeability, modifying intestinal immunity, and molecular mimicry. The gut microbial diversity, taxonomic profile, and functional potential of gut microbes are significantly altered in individuals with T1D as compared to healthy individuals. However, studies are still needed to identify the specific microbes and microbial metabolites that are involved in the development and pathogenesis of T1D. This will help the development of microbiome-based therapeutic strategies for the prevention and treatment of T1D. The present review article highlights the following: (i) the current knowledge and knowledge gaps in understanding the association between T1D and gut microbiome specifically focusing on the composition and functional potential of gut microbiome in children and adolescents, (ii) the possible mechanisms involved in gut microbiome-mediated T1D pathogenesis, and (iii) challenges and future direction in this field.Abbreviations: B/F ratio: Bacteroidetes to Firmicutes ratio; F/B ratio: Firmicutes to Bacteroidetes ratio; FDR: First-degree relatives; GPR: G protein-coupled receptors; HLA: human leucocyte antigen; IL: interleukin; IFN- γ: interferon-γ; KEGG: Kyoto Encyclopedia of Genes and Genomes; LPS: lipopolysaccharide; mTOR: mammalian target of rapamycin; PICRUSt: Phylogenetic Investigation of Communities by Reconstruction of Unobserved States; SCFA: short chain fatty acids; T1D: Type 1 diabetes; T2D: Type 2 diabetes; TJ: tight junction; T_regs: regulatory T cells.

Oral, Nasal, and Gut Microbiota in Parkinson's Disease

Parkinson's disease (PD) is the second most frequently diagnosed neurodegenerative disease. The purpose of this study was to investigate the link between microbiota composition in important mucosal interfaces (oral, nasal, and intestinal) and PD. Sequencing was undertaken of the V4-V5 region of the 16S ribosomal RNA (rRNA) gene of the microbiome from the oral cavity, nasal cavity, and gut of 91 PD patients and 91 healthy controls. Significant differences were found in microbiota composition in the oral cavity and gut, but not the nasal cavity, between PD patients and healthy controls after adjusting for age, gender, and body mass index (BMI). More genera in the oral cavity were significantly positively correlated with clinical characteristics, such as the HAMA and HAMD rating scales. The taxa c_Clostridia, o_Clostridiales, and f_Ruminococcaceae in the gut microbiota were associated with weight and MMSE score. Furthermore, as a result of dysbiosis, there was an enrichment of ion channel-, oxidative phosphorylation-, and carbohydrate metabolism-related pathways in the oral cavity and glycolysis/gluconeogenesis- and propanoate metabolism-related pathways in the intestine. Changes in these pathways can influence metabolism and inflammation, thereby contributing to PD pathogenesis. In addition, several subnetworks containing differentially abundant microbiota in the oral cavity and gut samples from PD patients may regulate microbial composition and function in PD. Overall, our results indicate that oral and gut dysbiosis may affect PD progression and provide a basis for understanding the pathogenesis of PD and identifying potential therapeutic targets for the treatment of this disease.

Sodium Acetate Inhibit TGF-β1-Induced Activation of Hepatic Stellate Cells by Restoring AMPK or c-Jun Signaling

Short-chain fatty acids (SCFAs) are crucial gut microbial metabolites that play a major role in the occurrence and development of hepatic fibrosis (HF). However, the effect of SCFAs on hepatic stellate cells (HSCs), the major pro-fibrogenic cells, is yet undefined. In this study, the effects of three major SCFAs (acetate, propionate, and butyrate) were assessed on the activation of HSCs. LX2 cells were activated with TGF-β1 and treated with sodium acetate (NaA), sodium propionate (NaP), or sodium butyrate (NaB). SCFA treatment significantly reduced the protein levels of α-SMA and the phosphorylation of Smad2 and decreased the mRNA expression of Acta2/Col1a1/Fn in cells compared to the TGF-β1 treatment. Among the three SCFAs, NaA revealed the best efficacy at alleviating TGF-β1-induced LX2 cell activation. Additionally, acetate accumulated in the cells, and G protein-coupled receptor (GPR) 43 silencing did not have any impact on the inhibition of LX2 cell activation by NaA. These findings indicated that NaA enters into the cells to inhibit LX2 cell activation independent of GPR43. The results of phosphokinase array kit and Western blot indicated that NaA increased the AMP-activated protein kinase (AMPK) activation and reduced the phosphorylation of c-Jun in cultured LX2 cells, and siRNA-peroxisome proliferator-activated receptor (PPAR) -γ abolished the inhibitory effects of NaA against TGF-β1-induced LX2 cell activation. In conclusion, this study showed that NaA inhibited LX2 cell activation by activating the AMPK/PPARγ and blocking the c-Jun signaling pathways. Thus, SCFAs might represent a novel and viable approach for alleviating HF.

Early development of the skin microbiome: therapeutic opportunities

As human skin hosts a diverse microbiota in health and disease, there is an emerging consensus that dysregulated interactions between host and microbiome may contribute to chronic inflammatory disease of the skin. Neonatal skin is a unique habitat, structurally similar to the adult but with a different profile of metabolic substrates, environmental stressors, and immune activity. The surface is colonized within moments of birth with a bias toward maternal strains. Initial colonists are outcompeted as environmental exposures increase and host skin matures. Nonetheless, early life microbial acquisitions may have long-lasting effects on health through modulation of host immunity and competitive interactions between bacteria. Microbial ecology and its influence on health have been of interest to dermatologists for >50 years, and an explosion of recent interest in the microbiome has prompted ongoing investigations of several microbial therapeutics for dermatological disease. In this review, we consider how recent insight into the host and microbial factors driving development of the skin microbiome in early life offers new opportunities for therapeutic intervention. IMPACT: Advancement in understanding molecular mechanisms of bacterial competition opens new avenues of investigation into dermatological disease. Primary development of the skin microbiome is determined by immunological features of the cutaneous habitat. Understanding coordinated microbial and immunological development in the pediatric patient requires a multidisciplinary synthesis of primary literature.

Caution, "normal" BMI: health risks associated with potentially masked individual underweight-EPMA Position Paper 2021

An increasing interest in a healthy lifestyle raises questions about optimal body weight. Evidently, it should be clearly discriminated between the standardised "normal" body weight and individually optimal weight. To this end, the basic principle of personalised medicine "one size does not fit all" has to be applied. Contextually, "normal" but e.g. borderline body mass index might be optimal for one person but apparently suboptimal for another one strongly depending on the individual genetic predisposition, geographic origin, cultural and nutritional habits and relevant lifestyle parameters-all included into comprehensive individual patient profile. Even if only slightly deviant, both overweight and underweight are acknowledged risk factors for a shifted metabolism which, if being not optimised, may strongly contribute to the development and progression of severe pathologies. Development of innovative screening programmes is essential to promote population health by application of health risks assessment, individualised patient profiling and multi-parametric analysis, further used for cost-effective targeted prevention and treatments tailored to the person. The following healthcare areas are considered to be potentially strongly benefiting from the above proposed measures: suboptimal health conditions, sports medicine, stress overload and associated complications, planned pregnancies, periodontal health and dentistry, sleep medicine, eye health and disorders, inflammatory disorders, healing and pain management, metabolic disorders, cardiovascular disease, cancers, psychiatric and neurologic disorders, stroke of known and unknown aetiology, improved individual and population outcomes under pandemic conditions such as COVID-19. In a long-term way, a significantly improved healthcare economy is one of benefits of the proposed paradigm shift from reactive to Predictive, Preventive and Personalised Medicine (PPPM/3PM). A tight collaboration between all stakeholders including scientific community, healthcare givers, patient organisations, policy-makers and educators is essential for the smooth implementation of 3PM concepts in daily practice.

Association between metabolic syndrome and periodontitis: The role of lipids, inflammatory cytokines, altered host response, and the microbiome

Periodontitis has been associated with many systemic diseases and conditions, including metabolic syndrome. Metabolic syndrome is a cluster of conditions that occur concomitantly and together they increase the risk of cardiovascular disease and double the risk of type 2 diabetes. In this review, we focus on the association between metabolic syndrome and periodontitis; however, we also include information on diabetes mellitus and cardiovascular disease, since these two conditions are significantly intertwined with metabolic syndrome. With regard to periodontitis and metabolic syndrome, to date, the vast majority of studies point to an association between these two conditions and also demonstrate that periodontitis can contribute to the development of, or can worsen, metabolic syndrome. Evaluating the effect of metabolic syndrome on the salivary microbiome, data presented herein support the hypothesis that the salivary bacterial profile is altered in metabolic syndrome patients compared with healthy patients. Considering periodontitis and these three conditions, the vast majority of human and animal studies point to an association between periodontitis and metabolic syndrome, diabetes, and cardiovascular disease. Moreover, there is evidence to suggest that metabolic syndrome and diabetes can alter the oral microbiome. However, more studies are needed to fully understand the influence these conditions have on each other.

Gut Microbiota and Neuroplasticity

The accumulating evidence linking bacteria in the gut and neurons in the brain (the microbiota-gut-brain axis) has led to a paradigm shift in the neurosciences. Understanding the neurobiological mechanisms supporting the relevance of actions mediated by the gut microbiota for brain physiology and neuronal functioning is a key research area. In this review, we discuss the literature showing how the microbiota is emerging as a key regulator of the brain's function and behavior, as increasing amounts of evidence on the importance of the bidirectional communication between the intestinal bacteria and the brain have accumulated. Based on recent discoveries, we suggest that the interaction between diet and the gut microbiota, which might ultimately affect the brain, represents an unprecedented stimulus for conducting new research that links food and mood. We also review the limited work in the clinical arena to date, and we propose novel approaches for deciphering the gut microbiota-brain axis and, eventually, for manipulating this relationship to boost mental wellness.

Steady-State Pre-rRNA Analysis to Investigate the Functional Microbiome

The gut microbiome is recognized as a critical regulator of human diseases. Constituents of the microbiota and their individual activities can affect a broad range of disease states related to autoimmunity, cancer, infection, metabolism, mental health, and toxicant exposure. A substantial number of microbiome species are not culturable, limiting their study in vitro. Sequencing methods have allowed quantification of the composition of the microbiome, but methods to characterize the physiological status of bacterial species remain limited. Ribosomal RNA precursors (pre-rRNAs) are species-specific intermediates in bacterial ribosomal synthesis, and their levels are highly responsive to environmental changes. Immediately before and during active growth, pre-rRNA levels are high, whereas in non-dividing cells, copy numbers are orders of magnitude lower. These dynamics are conserved in all bacterial species and occur exclusively in viable cells, allowing the specific characterization of living and functional bacteria in their native states. Pre-rRNA analysis has been shown to yield valuable real-time information on the physiology of individual bacterial species within complex samples, beyond what traditional qPCR and sequencing methods can offer. Herein, we describe a PCR-based protocol to interrogate and quantify the in situ growth status of bacterial species of interest within a complex microbiome. We also describe an in vitro protocol to characterize the pre-rRNA/growth relationship for a given bacterial species to provide greater context for values obtained from natural samples. Improved understanding of microbial physiological responses to exposures could reveal novel toxicological mechanisms, biomarkers, and potential treatments. © 2021 Wiley Periodicals LLC. Basic Protocol: Targeted steady-state pre-rRNA analysis Support Protocol: Characterization of pre-rRNA/growth relationship © 2021 by John Wiley & Sons, Inc.

An Update on the Potential Roles of E2F Family Members in Colorectal Cancer

Colorectal cancer (CRC) is a major health burden worldwide, and thus, optimised diagnosis and treatments are imperative. E2F transcription factors (E2Fs) are a family of transcription factors consisting of eight genes, contributing to the oncogenesis and development of CRC. Importantly, E2Fs control not only the cell cycle but also apoptosis, senescence, DNA damage response, and drug resistance by interacting with multiple signaling pathways. However, the specific functions and intricate machinery of these eight E2Fs in human CRC remain unclear in many respects. Evidence on E2Fs and CRC has been scattered on the related regulatory genes, microRNAs (miRNAs), and competing endogenous RNAs (ceRNAs). Accordingly, some drugs targeting E2Fs have been transferred from preclinical to clinical application. Herein, we have systemically reviewed the current literature on the roles of various E2Fs in CRC with the purpose of providing possible clinical implications for patient diagnosis and prognosis and future treatment strategy design, thereby furthering the understanding of the E2Fs.