Akkermansia muciniphila is a promising probiotic

Alterations in the Gut Microbiome of Individuals With Tuberculosis of Different Disease States

Objective

There is evidence that the gut microbiota play a regulatory role in the occurrence and progression of tuberculosis. The purpose of the current study was to explore the alterations in gut microbiome under different tuberculosis disease stages in the Uyghur population, clarify the composition of microbial taxonomy, search for microbial biomarkers and provide innovative ideas for individual immune prevention and for control strategies.

Design

A case–control study of Uyghur individuals was performed using 56 cases of pulmonary tuberculosis (PTB), 36 cases of latent tuberculosis infection (LTBI) and 50 healthy controls (HC), from which stool samples were collected for 16S rRNA gene sequencing.

Results

The results showed that the alpha diversity indexes of the PTB group were lower than those of the other two groups (P <0.001), while only observed species were different between LTBI and HC (P <0.05). Beta diversity showed differences among the three groups (P = 0.001). At the genus level, the relative abundance of Bifidobacterium and Bacteroides increased, while Roseburia and Faecalibacterium decreased in the PTB group, when compared with the other two groups, but the changes between the LTBI and HC groups were not significant. The classifier in the test set showed that the ability of the combined genus to distinguish between each two groups was 81.73, 87.26, and 86.88%, respectively, and the validation efficiency was higher than that of a single screened genus.

Conclusion

The gut microbiota of PTB patients was significantly disordered compared with LTBI and HC, while the changes of LTBI and HC were not significant. In the future, gut microbiota could be used as a non-invasive biomarker to assess disease activity.

Gut microbiome and plasma metabolome changes in rats after oral gavage of nanoparticles: sensitive indicators of possible adverse health effects

BACKGROUND

The oral uptake of nanoparticles is an important route of human exposure and requires solid models for hazard assessment. While the systemic availability is generally low, ingestion may not only affect gastrointestinal tissues but also intestinal microbes. The gut microbiota contributes essentially to human health, whereas gut microbial dysbiosis is known to promote several intestinal and extra-intestinal diseases. Gut microbiota-derived metabolites, which are found in the blood stream, serve as key molecular mediators of host metabolism and immunity.

RESULTS

Gut microbiota and the plasma metabolome were analyzed in male Wistar rats receiving either SiO2 (1000 mg/kg body weight/day) or Ag nanoparticles (100 mg/kg body weight/day) during a 28-day oral gavage study. Comprehensive clinical, histopathological and hematological examinations showed no signs of nanoparticle-induced toxicity. In contrast, the gut microbiota was affected by both nanoparticles, with significant alterations at all analyzed taxonomical levels. Treatments with each of the nanoparticles led to an increased abundance of Prevotellaceae, a family with gut species known to be correlated with intestinal inflammation. Only in Ag nanoparticle-exposed animals, Akkermansia, a genus known for its protective impact on the intestinal barrier was depleted to hardly detectable levels. In SiO2 nanoparticles-treated animals, several genera were significantly reduced, including probiotics such as Enterococcus. From the analysis of 231 plasma metabolites, we found 18 metabolites to be significantly altered in Ag-or SiO2 nanoparticles-treated rats. For most of these metabolites, an association with gut microbiota has been reported previously. Strikingly, both nanoparticle-treatments led to a significant reduction of gut microbiota-derived indole-3-acetic acid in plasma. This ligand of the arylhydrocarbon receptor is critical for regulating immunity, stem cell maintenance, cellular differentiation and xenobiotic-metabolizing enzymes.

CONCLUSIONS

The combined profiling of intestinal microbiome and plasma metabolome may serve as an early and sensitive indicator of gut microbiome changes induced by orally administered nanoparticles; this will help to recognize potential adverse effects of these changes to the host.

Interleukin-6 absence triggers intestinal microbiota dysbiosis and mucosal immunity in mice

Interleukin-6 (IL-6) in mucosal immune cells is involved in post-injury intestinal regeneration, inflammation responses, and gastric homeostasis. However, the interaction between IL-6 and the dynamic balance of gut microbiota (GM) remains unexplored. Intestinal pathology was assessed by hematoxylin and eosin and periodic acid-Schiff staining in wild-type (WT) and IL-6 gene knockout (KO) C57BL/6J mice. GM profiles were established via high-throughput sequencing of the fecal bacterial 16S rRNA gene. Intestinal α- and β-defensins were measured by quantitative real-time PCR; further, flow cytometry was performed to analyze isolated intraepithelial lymphocytes (IELs). Compared with the WT, IL-6 KO did not obviously change gut structures, but significantly reduced GM diversity, resulting in reduced metabolic pathways with decreased gram-positive but elevated gram-negative bacteria. More taxa alterations included differences at the phyla (e.g., increased Verrucomicrobia and decreased Firmicutes) and genera (e.g., increased Akkermansia and decreased Lactobacillus) levels. Absence of IL-6 also significantly increased intestinal expression of defensins α3 and α4 (Defa3 and Defa4) and the percentage of natural TCRγδ⁺ IELs, providing a molecular basis for triggering mucosal immune response. Therefore, IL-6 loss remodels GM composition and alters IEL maintenance, identifying IL-6 as a crucial cytokine for GM dysbiosis and mucosal immunity.

Akkermansia muciniphila: from its critical role in human health to strategies for promoting its abundance in human gut microbiome

Akkermansia muciniphila, a frequent colonizer in the gut mucous layer of individuals, has constantly been recognized as a promising candidate for the next generation of probiotics due to its biological advantages from in vitro and in vivo investigations. This manuscript comprehensively reviewed the features of A. muciniphila in terms of its function in host physiology and frequently utilized nutrition using the published peer-reviewed articles, which should present valuable and critical information to scientists, engineers, and even the general population. A. muciniphila is an important bacterium that shows host physiology. However, its physiological advantages in several clinical settings also have excellent potential to become a probiotic. Consequently, it can be stated that there is a coherent and direct relation between the biological activities of the gut microbiota, intestinal dysbiosis/eubiosis, and the population of A. muciniphila in the gut milieu, which is influenced by various genetical and nutritional factors. Current regulatory barriers, the need for large-scale clinical trials, and the feasibility of production must be removed before A muciniphila can be extensively used as a next-generation probiotic.

Antimetabolite Drugs Exhibit Distinctive Immunomodulatory Mechanisms and Effects on the Intestinal Microbiota in Experimental Autoimmune Uveitis

Purpose

The purpose of this study was to investigate the effect of antimetabolite drugs on T-cell responses and intestinal microbial composition in autoimmune uveitis.

Methods

Experimental autoimmune uveitis (EAU) was induced in C57BL/6J mice treated with 0.00625 mg/mL methotrexate (MTX) or 0.625 mg/mL mycophenolate mofetil (MMF) in drinking water for 4 weeks prior to immunization and 2 weeks thereafter. The effector T cell (Teff) and regulatory T cell (Treg) populations were identified using flow cytometry. The 16S rRNA gene sequencing was applied for gut microbiome characterization. DESeq2 analysis was used to discriminate relative abundances of taxa and PLS-DA to integrate cytometric and microbiome data between groups.

Results

Both MTX and MMF abrogated uveitis in EAU without clinical signs of toxicity as compared to water-fed controls. MTX reduced Teff and Treg expansion in peripheral tissues and eyes. MTX decreased alpha diversity, increased Akkermansia, and reduced Lachnoclostridium abundances. Conversely, MMF enhanced Tregs in the mesenteric lymph node and the eyes. In parallel, MMF increased the gut alpha diversity, including an increased abundance of Lachnospiraceae NK4A136 group and a decreased abundance of Lachnospiraceae UCG-001. A significant congruent correlation among intestinal microbial changes, T-cell responses, and clinical scores was observed for both antimetabolites.

Conclusions

Although MTX and MMF both abrogated uveitis in EAU, they showed different effects on T-cell subsets and the intestinal bacterial composition. This work indicates unique immunomodulation by each drug and is the first to demonstrate potential microbiota-related mechanisms.

Objetivo

Investigar el efecto de los fármacos antimetabolitos sobre las respuestas de células T y la composición microbiana intestinal en la uveítis autoinmune.

Métodos

Se indujo uveítis autoinmune experimental (UAE) en ratones C57BL/6J tratados con 0.00625 mg/ml de metotrexato (MTX) o 0.625 mg/ml de micofenolato mofetilo (MFM) en agua de bebida durante 4 semanas antes de la inmunización y 2 semanas después. Las poblaciones de células T efectoras (Tef) y reguladoras (Treg) se identificaron por citometría de flujo. La caracterización del microbioma intestinal se realizó mediante secuenciación del gen 16S ARNr. El análisis discriminante de abundancias relativas en los taxones se llevó a cabo por DESeq2 y se usó un análisis PLS-DA para integrar los datos microbianos y citométricos entre grupos.

Resultados

MTX y MFM inhibieron la UAE sin signos clínicos de toxicidad comparado con los controles. MTX disminuyó la expansión de Tef y Treg en los tejidos periféricos y oculares. MTX redujo la alfa diversidad, incrementando la abundancia de Akkermansia, y reduciendo la de Lachnoclostridium. En cambio, MFM aumentó los Tregs en el ganglio mesentérico y en los ojos. Paralelamente, MFM aumentó la alfa diversidad, incluyendo un aumento de la abundancia del grupo Lachnospiraceae NK4A136 y un descenso de la de Lachnospiraceae UCG-001. Se observó una correlación congruente significativa, para ambos fármacos, entre los cambios en el microbioma, las respuestas de células T y los grados clínicos de uveítis.

Conclusiones

Aunque ambos, MTX y MFM, suprimieron la UAE, mostraron efectos diferentes sobre los subtipos de células T y sobre la composición del microbioma. Este estudio indica un efecto inmunomodulador único para cada fármaco y es el primero en demostrar potenciales mecanismos relacionados con el microbioma.

Microbiota and body weight control: Weight watchers within?

BACKGROUND

Despite several decades of research, managing body weight remains an unsolved clinical problem. Health problems associated with dysregulated body weight, such as obesity and cachexia, exhibit several gut microbiota alterations. There is an increased interest in utilising the gut microbiota for body weight control, as it responds to intervention and plays an important role in energy extraction from food, as well as biotransformation of nutrients.

SCOPE OF THE REVIEW

This review provides an overview of the role of the gut microbiota in the physiological and metabolic alterations observed in two body weight dysregulation-related disorders, namely obesity and cachexia. Second, we assess the available evidence for different strategies, including caloric restriction, intermittent fasting, ketogenic diet, bariatric surgery, probiotics, prebiotics, synbiotics, high-fibre diet, and fermented foods - effects on body weight and gut microbiota composition. This approach was used to give insights into the possible link between body weight control and gut microbiota configuration.

MAJOR CONCLUSIONS

Despite extensive associations between body weight and gut microbiota composition, limited success could be achieved in the translation of microbiota-related interventions for body weight control in humans. Manipulation of the gut microbiota alone is insufficient to alter body weight and future research is needed with a combination of strategies to enhance the effects of lifestyle interventions.

SARS-CoV-2 triggered oxidative stress and abnormal energy metabolism in gut microbiota

Specific roles of gut microbes in COVID-19 progression are critical. However, the circumstantial mechanism remains elusive. In this study, shotgun metagenomic or metatranscriptomic sequencing was performed on fecal samples collected from 13 COVID-19 patients and controls. We analyzed the structure of gut microbiota, identified the characteristic bacteria, and selected biomarkers. Further, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations were employed to correlate the taxon alterations and corresponding functions. The gut microbiota of COVID-19 patients was characterized by the enrichment of opportunistic pathogens and depletion of commensals. The abundance of Bacteroides spp. displayed an inverse relationship with COVID-19 severity, whereas Actinomyces oris, Escherichia coli, and Streptococcus parasanguini were positively correlated with disease severity. The genes encoding oxidoreductase were significantly enriched in gut microbiome of COVID-19 group. KEGG annotation indicated that the expression of ABC transporter was upregulated, while the synthesis pathway of butyrate was aberrantly reduced. Furthermore, increased metabolism of lipopolysaccharide, polyketide sugar, sphingolipids, and neutral amino acids were found. These results suggested the gut microbiome of COVID-19 patients was in a state of oxidative stress. Healthy gut microbiota may enhance antiviral defenses via butyrate metabolism, whereas the accumulation of opportunistic and inflammatory bacteria may exacerbate COVID-19 progression.

Next-generation probiotics - do they open new therapeutic strategies for cancer patients?

Gut microbiota and its association with cancer development/treatment has been intensively studied during the past several years. Currently, there is a growing interest toward next-generation probiotics (NGPs) as therapeutic agents that alter gut microbiota and impact on cancer development. In the present review we focus on three emerging NGPs, namely Faecalibacterium prausnitzii, Akkermansia muciniphila, and Bacteroides fragilis as their presence in the digestive tract can have an impact on cancer incidence. These NGPs enhance gastrointestinal immunity, maintain intestinal barrier integrity, produce beneficial metabolites, act against pathogens, improve immunotherapy efficacy, and reduce complications associated with chemotherapy and radiotherapy. Notably, the use of NGPs in cancer patients does not have a long history and, although their safety remains relatively undefined, recently published data has shown that they are non-toxigenic. Notwithstanding, A. muciniphila may promote colitis whereas enterotoxigenic B. fragilis stimulates chronic inflammation and participates in colorectal carcinogenesis. Nevertheless, the majority of B. fragilis strains provide a beneficial effect to the host, are non-toxigenic and considered as the best current NGP candidate. Overall, emerging studies indicate a beneficial role of these NGPs in the prevention of carcinogenesis and open new promising therapeutic options for cancer patients.

Changes of Intestinal Microflora in Colorectal Cancer Patients after Surgical Resection and Chemotherapy

OBJECTIVE

The change of bacterial flora structure in colorectal cancer (CRC) patients after treatment is not clear. The aim of this study was to explore the change and function of intestinal microflora in CRC before and after treatment.

METHOD

The 16S conserved region V3+V4 of intestinal flora obtained from CRC patients was sequenced and analyzed. Alpha and beta diversity indices were used to analyze the abundance and structure of gut flora. FAPROTAX, BugBase, and Tax4Fun software were used to analyze the species phenotypes and Kyoto Encyclopedia of Genes and Genomes Ontology (KO) function pathways.

RESULTS

Total abundance and structure of species in CRC patients were significantly increased compared with healthy people (control group) (P < 0.05), but there was no significant difference between CRC patients before and after treatment (P > 0.05). There was significant difference in relative abundance of bacteria at different levels (phylum, class, order, family, genus, and species) between the CRC group with after operation (CRC_O group) and chemotherapy (CRC_C group) treatment, particularly Prevotellaceae_UCG-001, Akkermansia, Fusicatenibacter, Tyzzerella_4, Megamonas, etc. in genus level. The KO function analysis showed that most of the bacteria with differences were mainly involved in the biosynthesis of lipopolysaccharide (Megamonas, Megasphaera, and Ruminococcus torques_group), protein digestion and absorption, renin-angiotensin system pathway (Akkermansia, Eubacterium_ruminantium_group, and Eubacterium_nodatum_group genus), adipocytokine signaling pathway and peroxisome pathway (Tyzzerella_4, Phascolarctobacterium, Ruminococcus_gnavus_group), and so on.

CONCLUSION

The abundance of intestinal microflora in CRC patients was increased significantly contrasted to healthy people, and surgery and chemotherapy were hard to reduce this phenomenon. Megamonas was involved in lipopolysaccharide biosynthesis and carcinogenesis in colorectal cancer. Surgery and drug treatment did not reduced lipopolysaccharide biosynthesis but increased the number of probiotic Akkermansia population and reduced the pathogenic bacteria Tyzzerella_4, participate in adipocytokine signaling pathway, and affect metabolism.

The effects of angiotensin I-converting enzyme inhibitory peptide VGINYW and the hydrolysate of α-lactalbumin on blood pressure, oxidative stress and gut microbiota of spontaneously hypertensive rats

VGINYW is a highly active angiotensin I-converting enzyme (ACE) inhibitory peptide discovered from α-lactalbumin by an in vitro-in silico high throughput screening strategy. The aim of this study was to evaluate the antihypertensive effect of the peptide and the α-lactalbumin hydrolysates under 3 kDa (LH-3k), and illustrate the possible mechanism in spontaneously hypertensive rats (SHRs). SHRs were administered with VGINYW and LH-3k at doses of 5 mg per kg BW and 100 mg per kg BW, respectively. VGINYW and LH-3k could markedly decrease the systolic blood pressure (SBP) of the SHRs, and the maximal drops of 21 mmHg (2 h after administration) and 17 mmHg (4 h after administration) were achieved during the 8 hour test, respectively. When the agents were given once per day for 4 weeks, they caused a long-term decrease of 16 mmHg of SBP. VGINYW and LH-3k control the blood pressure through regulating the renin-angiotensin system by inhibiting the ACE activity and diminishing the angiotensin II level, and further upregulating the expression levels of the angiotensin-converting enzyme 2 and angiotensin type 2 receptor, and downregulating the expression of the angiotensin type 1 receptor. VGINYW and LH-3k could notably ameliorate the oxidative stress in the SHR as well. It is more important that the gavage of VGINYW and LH-3k could alleviate hypertension-associated intestinal microbiota dysbiosis by recovering the diversity of the gut microbiota and altering the key floras which are short chain fatty acid producers. In conclusion, VGINYW and LH-3k are effective functional ingredients for blood pressure control.

The anti-inflammatory effects of Akkermansia muciniphila and its derivates in HFD/CCL4-induced murine model of liver injury

Inflammation plays a critical role in the promotion of hepatocyte damage and liver fibrosis. In recent years the protective role of Akkermansia muciniphila, a next-generation beneficial microbe, has been suggested for metabolic and inflammatory disorders. In this study, we aimed to evaluate the effects of live and pasteurized A. muciniphila and its extra cellular vesicles (EVs) on inflammatory markers involved in liver fibrosis in a mouse model of a high-fat diet (HFD)/carbon tetrachloride (CCl₄)-induced liver injury. Firstly, the responses of hepatic stellate cells (HSCs) to live and pasteurized A. muciniphila and its EVs were examined in the quiescent and LPS-activated LX-2 cells. Next, the anti-inflammatory effects of different forms of A. muciniphila were examined in the mouse model of HFD/CCl₄-induced liver injury. The gene expression of various inflammatory markers was evaluated in liver, colon, and white adipose tissues. The cytokine secretion in the liver and white adipose tissues was also measured by ELISA. The results showed that administration of live and pasteurized A. muciniphila and its EVs leads to amelioration in HSCs activation. Based on data obtained from the histopathological analysis, an improvement in gut health was observed through enhancing the epithelium and mucosal layer thickness and strengthening the intestinal integrity in all treatments. Moreover, live A. muciniphila and its EVs had inhibitory effects on liver inflammation and hepatocytes damage. In addition, the tissue cytokine production and inflammatory gene expression levels revealed that live A. muciniphila and its EVs had more pronounced anti-inflammatory effects on liver and adipose tissues. Furthermore, EVs had better effects on the modulation of gene expression related to TLRs, PPARs, and immune response in the liver. In conclusion, the present results showed that oral administration of A. muciniphila and its derivatives for four weeks could enhance the intestinal integrity and anti-inflammatory responses of the colon, adipose, and liver tissues and subsequently prevent liver injury in HFD/CCL₄ mice.

Advances in understanding role of gut microbiota in immunotherapy for hepatocellular carcinoma

The gut microbiota plays an important role in the health of human being. Recent studies have shown that the intestinal flora is also associated with tumorigenesis and tumor immunotherapy. Immune checkpoint inhibitors have made significant progress in treating liver cancer. Although immune checkpoint inhibitors improve the survival of patients with liver cancer, there are still some patients who do not benefit from the therapy. Therefore, it is expected to enhance the therapeutic effectiveness of immunotherapy by altering the composition of the intestinal flora, particularly enriching the flora that may improve the effect of immunotherapy. This review focuses on the role of the gut microbiota in immunotherapy for hepatocellular carcinoma.

Oral Administration of Water Extract from Euglena gracilis Alters the Intestinal Microbiota and Prevents Lung Carcinoma Growth in Mice

The antitumor effects of a partially purified water extract from Euglena gracilis (EWE) and EWE treated by boiling (bEWE) were evaluated using orthotopic lung cancer syngeneic mouse models with Lewis lung carcinoma (LLC) cells. Daily oral administration of either EWE or bEWE started three weeks prior to the inoculation of LLC cells significantly attenuated tumor growth as compared to the phosphate buffered saline (PBS) control, and the attenuation was further enhanced by bEWE. The intestinal microbiota compositions in both extract-treated groups were more diverse than that in the PBS group. Particularly, a decrease in the ratio of Firmicutes to Bacteroidetes and significant increases in Akkermansia and Muribaculum were observed in two types of EWE-treated groups. Fecal microbiota transplantation (FMT) using bEWE-treated mouse feces attenuated tumor growth to an extent equivalent to bEWE treatment, while tumor growth attenuation by bEWE was abolished by treatment with an antibiotic cocktail. These studies strongly suggest that daily oral administration of partially purified water extracts from Euglena gracilis attenuates lung carcinoma growth via the alteration of the intestinal microbiota.

Curcumin Alleviates Dextran Sulfate Sodium-induced Colitis in Mice Through Regulating Gut Microbiota

SCOPE

Curcumin is a natural polyphenol compound with multiple pharmacologic activities. The present study aims to explore the potential therapeutic properties of curcumin on intestinal inflammatory diseases, including its anti-inflammatory, anti-oxidant, and anti-apoptotic properties, as well as their associations with altered intestinal microbiome.

METHODS AND RESULTS

DSS, i.e., Dextran Sulfate Sodium, (3%) was administered to C57BL/6J mice in the drinking water daily for 6 days in DSS and curcumin groups. Then mice in curcumin groups were orally administered with 50 or 150 mg/kg curcumin for 7 days. On day 13, mice were sacrificed. Results showed that oral administration with curcumin relieved macroscopic pathological manifestations, e.g. colon length and histological change. Moreover, it enhanced intestinal barrier via increasing expression of tight junction proteins, e.g. occludin, ZO-1, claudin-3; alleviated DSS-induced intestinal apoptosis via suppressing caspase-3 pathway; mitigated intestinal inflammation via inhibiting the MAPK/NFκB/STAT3 pathway. We also noticed that curcumin is beneficial for modulating abundance of some specific bacteria, including Akkermansia, Coprococcus, Roseburia, and Turicibacter, as well as families such as F16, Enterococcaceae, and Aerococcaceae. Most of the altered bacteria by curcumin are highly correlated with colitis-associated parameters.

CONCLUSION

curcumin shows therapeutic potential against colitis. It may be served as alternative medicine or adjuvant therapy in the treatment of colitis. This article is protected by copyright. All rights reserved.

Dynamic Alterations of the Gut Microbial Pyrimidine and Purine Metabolism in the Development of Liver Cirrhosis

Background: Liver cirrhosis is the common end-stage of liver disease which lacks effective treatment, thus studies to determine prevention targets are an urgent need. The intestinal microbiota (IM) play important roles in modulating liver diseases which are mediated by microbial metabolites. Despite decades of growing microbial studies, whether IM contribute to the development of cirrhosis and the intimate metabolic link remain obscure. Here, we aimed to reveal the dynamic alterations of microbial composition and metabolic signatures in carbon tetrachloride (CCl₄)-induced liver cirrhosis mice.

Methods: CCl₄-treated mice or normal control (NC) were sacrificed (n = 10 per group) after 5 and 15 weeks of intervention. The disease severity was confirmed by Masson’s trichrome or Sirius red staining. Metagenomics sequencing and fecal untargeted metabolomics were performed to evaluate the composition and metabolic function of IM in parallel with the development of cirrhosis.

Results: The CCl₄-treated mice presented liver fibrosis at 5 weeks and liver cirrhosis at 15 weeks indicated by collagen deposition and pseudo-lobule formation, respectively. Mice with liver cirrhosis showed distinct microbial composition from NC, even in the earlier fibrosis stage. Importantly, both of the liver fibrosis and cirrhosis mice were characterized with the depletion of Deltaproteobacteria (p < 0.05) and enrichment of Akkermansia (p < 0.05). Furthermore, fecal metabolomics revealed distinguished metabolomics profiles of mice with liver fibrosis and cirrhosis from the NC. Notably, pathway enrichment analysis pointed to remarkable disturbance of purine (p < 0.001 at 5 weeks, p = 0.034 at 15 weeks) and pyrimidine metabolic pathways (p = 0.005 at 5 weeks, p = 0.006 at 15 weeks) during the development of liver cirrhosis. Interestingly, the disorders of pyrimidine and purine metabolites like the known microbial metabolites thymidine and 2′-deoxyuridine had already occurred in liver fibrosis and continued in cirrhosis.

Conclusion: These novel findings indicated the crucial role of IM-modulated pyrimidine and purine metabolites in the development of liver cirrhosis, which provides microbial targets for disease prevention.

Prevotella histicola Mitigated Estrogen Deficiency-Induced Depression via Gut Microbiota-Dependent Modulation of Inflammation in Ovariectomized Mice

Background

Estrogen deficiency-induced depression is closely associated with an imbalance in intestinal microbiota and inflammation. Prevotella histicola (P. histicola), an emerging probiotic, apparently improves inflammatory responses. This study aims to verify the antidepressant-like effects of P. histicola and clarify its potential mechanisms.

Methods

Mice were treated with P. histicola and cohousing after ovariectomy (OVX). The changes in depression-like behaviors among mice were examined by behavioral tasks, and alterations in the microbiota were detected through 16S rRNA sequencing. Changes in neuronal injury, protein synthesis, inflammatory factors, intestinal permeability, and nerve proliferation were observed by H&E, Nissl staining, qRT-PCR, western blotting, and immunofluorescence.

Results

P. histicola significantly reduces depression-like behaviors and neuronal damage induced by estrogen deficiency. Additionally, P. histicola significantly increases the abundance of intestinal flora, especially Lactobacillus and Akkermansia. Meanwhile, the cohoused mice also had a better emotional state and neutral structure compared with OVX mice. P. histicola was also found to upregulate tight junction proteins ZO-1, occludin, claudin-1, and MUC2 in the ileum and colon and reduce the levels of inflammatory factors VCAM, MCP-1, IL-6, IL-8, and TNF-α, mainly in the ileum, colon, and decrease the expression of COX-2, TLR4, Myd88, JNK, MCP-1, IL-6, IL-8, and TNF-α in the hippocampus. Moreover, significant downregulation of apoptosis (caspase-3 and caspase-8) and upregulation of neurotrophic factors (BDNF and Ki-67) were observed after P. histicola treatment.

Conclusion

Our data show that P. histicola significantly mitigates depression of OVX mice through improvement in intestinal microbiota to repair intestinal leakage and inhibit central inflammation to promote the expression of BDNF for hippocampal neurogenesis. P. histicola may be therapeutically beneficial for PMD.

Chemically Protected Sodium Butyrate Improves Growth Performance and Early Development and Function of Small Intestine in Broilers as One Effective Substitute for Antibiotics

The purpose of this study was to investigate the effects of chemically protected sodium butyrate (CSB) on growth performance and the early development and function of small intestine in broilers as one potential substitute for antibiotics. A total of 192 one-day-old Arbor Acres male broilers were randomly assigned into three dietary treatment groups (eight replicates per treatment): the control (CON) diet; ANT diet, CON diet supplemented with the antibiotics (enramycin, 8 mg/kg and aureomycin, 100 mg/kg); CSB diet, CON diet supplemented with 1000 mg/kg CSB, respectively. The results showed that dietary CSB and antibiotics addition significantly improved the growth performance of broilers by increasing the body weight gain (BWG) and feed conversion ratio (FCR) during different stages (p < 0.05). On day 21, the supplement of CSB in diet improved the structure of small intestine (duodenum, jejunum, and ileum) in broilers by increasing the ratio of villus height to crypt depth (VH/CD) (p < 0.05) and enhanced the butyric acid (BA) (p < 0.05) and total short chain fatty acids (SCFA) concentrations of small intestine (jejunum and ileum) compared with the CON and ANT diets. Besides that, the superoxide dismutase (SOD), total antioxidant capacity (TAC) and TAC to malondialdehyde (TAC/MDA) ratio of the ileal and jejunal mucosa were significantly higher (p < 0.05) in the CSB and ANT than in the CON. In addition, the supplement of CSB in diet markedly significantly enhanced α-amylase, lipase, and trypsin activities of the ileum (p < 0.05) as compared to the ANT diet. 16S rRNA gene sequencing indicated that CSB markedly increased the microbiota diversity of ileum in broilers at 21 days of age as compared to CON and ANT (p < 0.05). Furthermore, we found that Firmicutes was the predominant phyla and Lactobacillus was the major genus in the ileum of broilers. Compared with the ANT diet, the supplement of CSB in diet increased the relative abundance of some genera microbiota (e.g., Candidatus_Arthromitus, Romboutsia) by decreasing the relative abundance of Lactobacillus. Moreover, Akkermansia in the CSB was the highest in comparison to that in the CON and ANT. In addition, Kitasatospora that belongs to the phylum Actinobacteriota was only found in ileum of broilers fed the ANT diet. In summary, the supplement of 1000 mg/kg CSB in the diet improved the growth performance by promoting early development and function of the small intestine, which is associated with the regulation of intestinal flora and reestablishment of micro-ecological balance in broilers. Thus, CSB has great potential value as one of effective substitutes for in-feed antibiotics in the broiler industry.

Effect of Dietary Protein and Processing on Gut Microbiota-A Systematic Review

The effect of diet on the composition of gut microbiota and the consequent impact on disease risk have been of expanding interest. The present review focuses on current insights of changes associated with dietary protein-induced gut microbial populations and examines their potential roles in the metabolism, health, and disease of animals. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol was used, and 29 highly relevant articles were obtained, which included 6 mouse studies, 7 pig studies, 15 rat studies, and 1 in vitro study. Analysis of these studies indicated that several factors, such as protein source, protein content, dietary composition (such as carbohydrate content), glycation of protein, processing factors, and protein oxidation, affect the digestibility and bioavailability of dietary proteins. These factors can influence protein fermentation, absorption, and functional properties in the gut and, consequently, impact the composition of gut microbiota and affect human health. While gut microbiota can release metabolites that can affect host physiology either positively or negatively, the selection of quality of protein and suitable food processing conditions are important to have a positive effect of dietary protein on gut microbiota and human health.

A. muciniphila Supplementation in Mice during Pregnancy and Lactation Affects the Maternal Intestinal Microenvironment

During pregnancy and lactation, considerable factors that affect the maternal microbiome are associated with the advancement of numerous diseases, which can potentially affect offspring health. Probiotics have shown potential for the maintenance of microbiota homeostasis of mothers in this period. The specific objective of this study was to investigate whether the application of Akkermansia muciniphila (A. muciniphila) during pregnancy and lactation impacts maternal and offspring health. Here we show that dams fed with A. muciniphila is safe, enhances the intestinal barrier and alters gut microbiota composition and diversity at the end of lactation, including the significant enrichment of A. muciniphila and Ruminococcus_1 in offspring from probiotic-fed dams. However, compared with the control group, the fecal metabolites of the A. muciniphila group only changed slightly. Additionally, A. muciniphila supplementation did not significantly increase the abundance of A. muciniphila in the fecal microbiota of offspring mice. Compared with the control group, the fecal metabolic profile of three-week-old offspring of mice fed with A. muciniphila were significantly changed, containing the D-glutamine and D-glutamate metabolism pathways. These results provided evidence that A. muciniphila supplementation in mice during pregnancy and lactation is safe and seemed to have a more beneficial effect on dams. In the future, using probiotics to regulate maternal microbiomes during pregnancy and lactation could be shown to have a more lasting and beneficial effect.

Mechanism of Neonatal Intestinal Injury Induced by Hyperoxia Therapy

High concentration oxygen is widely used in the treatment of neonates, which has a significant effect on improving blood oxygen concentration in neonates with respiratory distress. The adverse effects of hyperoxia therapy on the lung, retina, and neurodevelopment of newborns have been extensively studied, but less attention has been paid to intestinal damage caused by hyperoxia therapy. In this review, we focus on the physical, immune, and microorganism barriers of the intestinal tract and discuss neonatal intestinal tract damage caused by hyperoxia therapy and analyze the molecular mechanism of intestinal damage caused by hyperoxia in combination with necrotizing enterocolitis.

The Gut Microbiome as a Regulator of the Neuroimmune Landscape

The gut microbiome influences many host physiologies, spanning gastrointestinal function, metabolism, immune homeostasis, neuroactivity, and behavior. Many microbial effects on the host are orchestrated by bidirectional interactions between the microbiome and immune system. Imbalances in this dialogue can lead to immune dysfunction and immune-mediated conditions in distal organs including the brain. Dysbiosis of the gut microbiome and dysregulated neuroimmune responses are common comorbidities of neurodevelopmental, neuropsychiatric, and neurological disorders, highlighting the importance of the gut microbiome–neuroimmune axis as a regulator of central nervous system homeostasis. In this review, we discuss recent evidence supporting a role for the gut microbiome in regulating the neuroimmune landscape in health and disease.

Expected final online publication date for the Annual Review of Immunology, Volume 40 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Performance of distinct microbial based solutions in a Campylobacter infection challenge model in poultry

BACKGROUND

Antibiotic growth promoters (AGPs) are commonly used within poultry production to improve feed conversion, bird growth, and reduce morbidity and mortality from clinical and subclinical diseases. Due to the association between AGP usage and rising antimicrobial resistance, the industry has explored new strategies including the use of probiotics and other microbial-based interventions to promote the development of a healthy microbiome in birds and mitigate against infections associated with food safety and food security. While previous studies have largely focused on the ability of probiotics to protect against Clostridium perfringens and Salmonella enterica, much less is known concerning their impact on Campylobacter jejuni, a near commensal of the chicken gut microbiome that nevertheless is a major cause of food poisoning in humans.

RESULTS

Here we compare the efficacy of four microbial interventions (two single strain probiotics, the bacterium-Pediococcus acidilactici, and the yeast-Saccharomyces cerevisiae boulardii; and two complex, competitive exclusion, consortia-Aviguard and CEL) to bacitracin, a commonly used AGP, to modulate chicken gut microbiota and subsequently impact C. jejuni infection in poultry. Cecal samples were harvested at 30- and 39-days post hatch to assess Campylobacter burden and examine their impact on the gut microbiota. While the different treatments did not significantly decrease C. jejuni burden relative to the untreated controls, both complex consortia resulted in significant decreases relative to treatment with bacitracin. Analysis of 16S rDNA profiles revealed a distinct microbial signature associated with each microbial intervention. For example, treatment with Aviguard and CEL increased the relative abundance of Bacteroidaceae and Rikenellaceae respectively. Furthermore, Aviguard promoted a less complex microbial community compared to other treatments.

CONCLUSIONS

Depending upon the individual needs of the producer, our results illustrate the potential of each microbial interventions to serve flock-specific requirements.

Intestinal Flora: A Potential New Regulator of Cardiovascular Disease

Although substantial progress has been made in reducing the burden of the disease by preventing the risk factors of cardiovascular disease (CVD), potential risk factors still exist and lead to its progression. In recent years, numerous studies have revealed that intestinal flora can interfere with the physiological processes of the host through changes in composition and function or related metabolites. Intestinal flora thus affects the occurrence and development of a variety of CVDs, including atherosclerosis, ischemic heart disease, and heart failure. Moreover, studies have found that interventions for intestinal flora and its metabolites provide new opportunities for CVD treatment. This article mainly discusses the interaction between the human intestinal flora and its metabolites, the occurrence and development of CVD, and the potential of intestinal flora as a new target for the diagnosis and treatment of CVD.

Lactobacillus kefiranofaciens ZW18 from Kefir enhances the anti-tumor effect of anti-programmed cell death 1 (PD-1) immunotherapy by modulating gut microbiota

The research of probiotics assisting PD-1 inhibitors in anti-tumor has attracted widespread attention. Therefore, it is significative to find new probiotic strains with PD-1 inhibitors promoting effect. This study aims...

The Effects of Feed Supplementing Akkemansia muciniphila on Incidence, Severity, and Gut Microbiota of Necrotic Enteritis in Chickens

Akkermansia muciniphila (AM) is a mucin-degrading anaerobe, exerting beneficial effects on gut integrity improvement, inflammatory alleviation, and metabolic regulations in humans. Excess amounts of mucin and mucogenesis in the gut facilitate the development of necrotic enteritis (NE) in chickens. The study aimed to evaluate the effects of oral inoculation of AM on NE prevention and gut modulation in a NE-reproduced model coinfecting with Clostridium perfringens (CP) and Eimeria parasites. A total of 105 commercial 1-day-old broilers were randomly allocated into 5 groups, respectively challenged with Eimeria (Eimeria group), Eimeria and CP (Eimeria+CP group), Eimeria and CP with AM (Eimeria+CP+AM group), Eimeria and AM (Eimeria+AM group), and a placebo (Noninfected group). The treatment of AM exhibited a low degree of amelioration on NE severity. The application neither protected broilers from NE by decreasing NE-positive numbers nor reached a significant reduction in lesion scores in the small intestines. The development of NE reduced species diversity in jejunal microbiota; the pretreatments of AM exacerbated the consequence by losing species richness and promoted the similarity of the jejunal microbial community presented in the Eimeria+CP group. The participation of AM enhanced the increments of genera Clostridium sensu stricto 1 and Escherichia_Shigella and decreased the number of Lactobacillus. The significant variations of genera Clostridium sensu stricto 1 and Lactobacillus in jejunal microbiota were associated with NE development and promotion. In conclusion, oral inoculation of AM promoted the development of NE and modulated the jejunal microbiota favorable for CP overgrowth in broilers. The application of AM as a probiotic in broilers should be cautious on account of the effects to predispose NE.

Gender Differences in Gut Microbiome Composition Between Schizophrenia Patients With Normal Body Weight and Central Obesity

BACKGROUND

Obesity is a common health problem among patients with schizophrenia, but the precise mechanisms are not fully understood. There has been much interest in the relationship between gut microbiome and development of obesity. Gender-dependent microbial alteration has been reported in previous studies. However, the gender factor in gut microbiome composition of schizophrenia patients has been less investigated. Our study aimed to identify differences in gut microbiota between schizophrenia patients with normal weight and central obesity and investigate the gender specific features.

METHOD

Twenty participants (10 males, 10 females) with central obesity (CO) and 20 participants (10 males, 10 females) with normal weight (NW) were recruited from two rehabilitation wards in a psychiatric hospital in central Taiwan. Fecal samples from 40 participants were processed for microbiota analysis. The intestinal microbiota composition was analyzed using next-generation sequencing and QIIME software.

RESULTS

Significantly higher richness of gut microbiota at the class level (measured by the number of observed OTUs) was observed in female NW subjects than in female CO subjects (P = 0.033). Furthermore, female NW subjects showed higher alpha diversity at both phylum and class levels (measured by the Shannon, Simpson, and Inverse-Simpson indexes) compared with female CO subjects. Males showed no significant difference in alpha diversity between groups. Taxonomic analysis showed that female CO subjects had significantly lower abundance of Verrucomicrobia (P = 0.004) at the phylum level, reduced abundance of Akkermansia (P = 0.003) and elevated level of Prevotella (P = 0.038) and Roseburia (P = 0.005) at the genus level.

CONCLUSIONS

The present results evidenced altered microbiome composition in schizophrenia patients with central obesity and further suggested the role of the gender factor in the process of gut dysbiosis.

Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases

The human intestine hosts diverse microbial communities that play a significant role in maintaining gut-skin homeostasis. When the relationship between gut microbiome and the immune system is impaired, subsequent effects can be triggered on the skin, potentially promoting the development of skin diseases. The mechanisms through which the gut microbiome affects skin health are still unclear. Enhancing our understanding on the connection between skin and gut microbiome is needed to find novel ways to treat human skin disorders. In this review, we systematically evaluate current data regarding microbial ecology of healthy skin and gut, diet, pre- and probiotics, and antibiotics, on gut microbiome and their effects on skin health. We discuss potential mechanisms of the gut-skin axis and the link between the gut and skin-associated diseases, such as psoriasis, atopic dermatitis, acne vulgaris, rosacea, alopecia areata, and hidradenitis suppurativa. This review will increase our understanding of the impacts of gut microbiome on skin conditions to aid in finding new medications for skin-associated diseases.

Gut microbiota modulation by prednisolone in a rat kindling model of pentylenetetrazol (PTZ)-induced seizure

The gut microbiota is a complex community composed by several microorganisms that interact in the maintenance of homeostasis and contribute to physiological processes, including brain function. The relationship of the taxonomic composition of the gut microbiota with neurological diseases such as autism, Parkinson's, Alzheimer's, anxiety, and depression is widely recognized. The immune system is an important intermediary between the gut microbiota and the central nervous system, being one of the communication routes of the gut-brain axis. Although the complexity of the relationship between inflammation and epilepsy has not yet been elucidated, inflammatory processes are similar in many ways to the consequences of dysbiosis and contribute to disease progression. This study aimed to analyze the taxonomic composition of the gut microbiota of rats treated with prednisolone in a kindling model of epilepsy. Male Wistar rats (90 days, n = 24) divided into four experimental groups: sodium chloride solution 0.9 g%, diazepam 2 mg/kg, prednisolone 1 mg/kg, and prednisolone 5 mg/kg administered intraperitoneally (i.p.) for 14 days. The kindling model was induced by pentylenetetrazole (PTZ) 25 mg/kg i.p. on alternate days. The taxonomic profile was established by applying metagenomic DNA sequencing. There was no change in alpha diversity, and the composition of the gut microbiota between prednisolone and diazepam was similar. The significant increase in Verrucomicrobia, Saccharibacteria, and Actinobacteria may be related to the protective activity against seizures and inflammatory processes that cause some cases of epilepsy. Further studies are needed to investigate the functional influence that these species have on epilepsy and the inflammatory processes that trigger it.

Modifying the Microbiome as a Potential Mechanism of Photobiomodulation: A Case Report

Objective: The objective of this case study was to elucidate the effect of photobiomodulation (PBM) on the microbiome. Background: The gut microbiome has been identified as a key component of health, with gut dysbiosis, characterized by decreased microbial diversity and an altered microbial composition, being recognized as instrumental in many diseases and disorders. Previous research has suggested that the gut microbiome can be favorably altered in animal models using PBM. Materials and methods: The participant had their microbiome tested on nine occasions, three times before any treatment, three times after radiotherapy and commencement of immunotherapy for breast cancer, and three times after PBM treatment. The PBM treatment consisted of infrared laser treatment (904 nm; 700 Hz pulse frequency, 861.3 total joules) to the abdomen three times per week for 11 weeks. Results: The microbiome of the participant showed significant changes in diversity after PBM treatment, but not after cancer therapy, with an increase in the number of known beneficial bacteria (Akkermansia, Faecalibacterium, and Roseburia) and decrease in the number of potentially pathogenic genera. Conclusions: The results suggested the possibility that PBM may alter the microbiome and thus it represents a therapeutic avenue for chronic diseases with otherwise limited treatment options.

Sleep, circadian rhythm and gut microbiota: alterations in Alzheimer's disease and their potential links in the pathogenesis

ABSTRATCIn recent years, emerging studies have observed gut microbiota (GM) alterations in Alzheimer's disease (AD), even in individuals with mild cognitive impairment (MCI). Further, impaired sleep and circadian patterns are common symptoms of AD, while sleep and circadian rhythm disruption (SCRD) is associated with greater β-amyloid (Aβ) burden and AD risk, sometimes years before the clinical onset of AD. Moreover, reports have demonstrated that GM and its metabolites exhibit diurnal rhythmicity and the role of SCRD in dampening the GM rhythmicity and eubiosis. This review will provide an evaluation of clinical and animal studies describing GM alterations in distinct conditions, including AD, sleep and circadian disruption. It aims to identify the overlapping and distinctive GM alterations in these conditions and their contributions to pathophysiology. Although most studies are observational and use different methodologies, data indicate partial commonalities in GM alterations and unanimity at functional level. Finally, we discuss the possible interactions between SCRD and GM in AD pathogenesis, as well as several methodological improvements that are necessary for future research.

The Synbiotic Combination of Akkermansia muciniphila and Quercetin Ameliorates Early Obesity and NAFLD through Gut Microbiota Reshaping and Bile Acid Metabolism Modulation

Gut microbiota plays a key role in obesity and non-alcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. We aim to evaluate a nutritional intervention together with the administration of the bacteria Akkermansia muciniphila and the antioxidant quercetin in an in vivo model of early obesity and NAFLD. 21-day-old rats were fed with control or high-fat diet for six weeks. Then, all animals received control diet supplemented with/without quercetin and/or A. muciniphila for three weeks. Gut microbiota, NAFLD-related parameters, circulating bile acids (BAs) and liver gene expression were analyzed. The colonization with A. muciniphila was associated with less body fat, while synbiotic treatment caused a steatosis remission, linked to hepatic lipogenesis modulation. The synbiotic promoted higher abundance of Cyanobacteria and Oscillospira, and lower levels of Actinobacteria, Lactococcus, Lactobacillus and Roseburia. Moreover, it favored elevated unconjugated hydrophilic BAs plasma levels and enhanced hepatic expression of BA synthesis and transport genes. A. muciniphila correlated with circulating BAs and liver lipid and BA metabolism genes, suggesting a role of this bacterium in BA signaling. Beneficial effects of A. muciniphila and quercetin combination are driven by gut microbiota modulation, the shift in BAs and the gut-liver bile flow enhancement.

Rheum tanguticum Alleviates Cognitive Impairment in APP/PS1 Mice by Regulating Drug-Responsive Bacteria and Their Corresponding Microbial Metabolites

Drugs targeting intestinal bacteria have shown great efficacy for alleviating symptoms of Alzheimer’s disease (AD), and microbial metabolites are important messengers. Our previous work indicated that Rheum tanguticum effectively improved cognitive function and reshaped the gut microbial homeostasis in AD rats. However, its therapeutic mechanisms remain unclear. Herein, this study aimed to elaborate the mechanisms of rhubarb for the treatment of AD by identifying effective metabolites associated with rhubarb-responsive bacteria. The results found that rhubarb reduced hippocampal inflammation and neuronal damage in APP/PS1 transgenic (Tg) mice. 16S rRNA sequencing and metabolomic analysis revealed that gut microbiota and their metabolism in Tg mice were disturbed in an age-dependent manner. Rhubarb-responsive bacteria were further identified by real-time polymerase chain reaction (RT-PCR) sequencing. Four different metabolites reversed by rhubarb were found in the position of the important nodes on rhubarb-responsive bacteria and their corresponding metabolites combined with pathological indicators co-network. Furthermore, in vitro experiments demonstrated o-tyrosine not only inhibited the viabilities of primary neurons as well as BV-2 cells, but also increased the levels of intracellular reactive oxygen species and nitric oxide. In the end, the results suggest that rhubarb ameliorates cognitive impairment in Tg mice through decreasing the abundance of o-tyrosine in the gut owing to the regulation of rhubarb-responsive bacteria. Our study provides a promising strategy for elaborating therapeutic mechanisms of bacteria-targeted drugs for AD.

Streptozotocin-induced hyperglycemia alters the cecal metabolome and exacerbates antibiotic-induced dysbiosis

It is well established in the microbiome field that antibiotic (ATB) use and metabolic disease both impact the structure and function of the gut microbiome. But how host and microbial metabolism interacts with ATB susceptibility to affect the resulting dysbiosis remains poorly understood. In a streptozotocin-induced model of hyperglycemia (HG), we use a combined metagenomic, metatranscriptomic, and metabolomic approach to profile changes in microbiome taxonomic composition, transcriptional activity, and metabolite abundance both pre- and post-ATB challenge. We find that HG impacts both microbiome structure and metabolism, ultimately increasing susceptibility to amoxicillin. HG exacerbates drug-induced dysbiosis and increases both phosphotransferase system activity and energy catabolism compared to controls. Finally, HG and ATB co-treatment increases pathogen susceptibility and reduces survival in a Salmonella enterica infection model. Our data demonstrate that induced HG is sufficient to modify the cecal metabolite pool, worsen the severity of ATB dysbiosis, and decrease colonization resistance.

Ginsenoside Rb1 ameliorates Glycemic Disorder in Mice With High Fat Diet-Induced Obesity via Regulating Gut Microbiota and Amino Acid Metabolism

Accumulating evidences suggested an association between gut microbiome dysbiosis and impaired glycemic control. Ginsenoside Rb1 (Rb1) is a biologically active substance of ginseng, which serves anti-diabetic effects. However, its working mechanism especially interaction with gut microbes remains elusive in detail. In this study, we investigated the impact of Rb1 oral supplementation on high fat diet (HFD) induced obesity mice, and explored its mechanism in regulating blood glucose. The results showed that higher liver weight and lower cecum weight were observed in HFD fed mice, which was maintained by Rb1 administration. In addition, Rb1 ameliorated HFD induced blood lipid abnormality and improved insulin sensitivity. Several mRNA expressions in the liver were measured by quantitative real-time PCR, of which UCP2, Nr1H4, and Fiaf were reversed by Rb1 treatment. 16S rRNA sequencing analysis indicated that Rb1 significantly altered gut microbiota composition and increased the abundance of mucin-degrading bacterium Akkermansia spp. compared to HFD mice. As suggested via functional prediction, amino acid metabolism was modulated by Rb1 supplementation. Subsequent serum amino acids investigation indicated that several diabetes associated amino acids, like branched-chain amino acids, tryptophan and alanine, were altered in company with Rb1 supplementation. Moreover, correlation analysis firstly implied that the circulation level of alanine was related to Akkermansia spp.. In summary, Rb1 supplementation improved HFD induced insulin resistance in mice, and was associated with profound changes in microbial composition and amino acid metabolism.

Akkermansia muciniphila – obiecujący kandydat na probiotyk nowej generacji

W ostatnich czasach można zaobserwować duży wzrost zainteresowania relacjami między człowiekiem a mikroorganizmami zasiedlającymi jego organizm. Licznie występują w oraz na ciele człowieka, a ich liczba przekracza liczbę komórek ludzkiego organizmu. Udoskonalenie technik badawczych pozwala lepiej zrozumieć molekularne podłoże tych oddziaływań, co być może pozwoli na wykorzystanie w terapiach tych mikroorganizmów, które korzystnie wpływają na organizm człowieka. W artykule podsumowano dotychczasową wiedzę na temat fizjologii licznie występującej w przewodzie pokarmowym bakterii Akkermansia muciniphila i jej wpływu na organizm gospodarza. Opisano właściwości A. muciniphila, jej funkcjonowanie w środowisku przewodu pokarmowego oraz relacje (zarówno antagonistyczne jak i symbiotyczne) z innymi tam bytującymi mikroorganizmami. Przedstawiono także mechanizmy oddziaływania A. muciniphila na barierę jelitową, układ immunologiczny oraz metabolizm energetyczny gospodarza. Ponadto opisano jej rolę w patogenezie i terapii chorób, w tym m.in. cukrzycy typu 2, nieswoistego zapalenia jelit, zaburzeń neurologicznych, astmy, a także jej wpływ na odpowiedź pacjenta na terapie przeciwnowotworowe oparte na działaniu układu odpornościowego. Duże zainteresowanie tą bakterią, a także przytoczone wyniki badań, w tym tych sprawdzających bezpieczeństwo jej stosowania, wskazują, że A. muciniphila może być obiecującym kandydatem na probiotyk nowej generacji. Niewątpliwie jednak przed dopuszczeniem A. muciniphila do powszechnego stosowania konieczne są dalsze badania z udziałem ludzi, a także wnikliwa ocena bezpieczeństwa jej stosowania.

Dietary plant sterols prevented cholesterol gallstone formation in mice

Cholesterol gallstone disease is a common global condition. This study investigated the role of plant sterols (PS) in the prevention of gallstone formation and the underlying mechanisms. Adult male mice were fed a lithogenic diet (LD) alone or supplemented with PS (LD-ps), phospholipids (LD-pl) or both PS and phospholipids (LD-ps/pl) for 8 weeks. Incidences of gallstone formation were compared among the groups. Lipids in the bile, liver and serum were analyzed. The expression of genes involved in cholesterol absorption, transport and metabolism in the liver and small intestine was determined. The incidences of gallstone formation were 100% (10/10), 20% (2/10), 100% (10/10) and 40% (4/10) in the LD, LD-ps, LD-pl and LD-ps/pl groups, respectively. Serum cholesterol and intestinal cholesterol absorption were decreased in PS-supplemented mice. The expression of genes related to cholesterol transport and metabolism in the liver was down-regulated by dietary PS. PS supplementation decreased Niemann-Pick C1-like 1 expression in the small intestine and reduced intestinal cholesterol absorption. Our results demonstrated that PS could inhibit intestinal cholesterol absorption and thus prevent cholesterol gallstone formation.

Immune response variations and intestinal flora changes in mastitis induced by three Streptococcus uberis strains

Streptococcus uberis is a common cause of mastitis. The pathogenicity among different strains of S. uberis and the resultant host immune responses remain to be elucidated. Herein, we document immune responses among three strains of S. uberis, and preliminary explore whether and how intestinal immunity plays a role in host anti-infection processes. Mice have been proved to be effective experimental animals for bovine mastitis, so utilizing a mouse intramammary infection model, we assay immune responses and gut flora changes of three S. uberis strains by histopathologic examination, RT-PCR, Western blot, and 16s ribosomal DNA sequencing. We find that the immune responses among the three sequence-type (ST) S. uberis strains may be linked to the hasA/B and lbp virulence genes, and the beta diversity of the intestine may be independent of the ST of S. uberis. Twenty phyla and 30 genera of intestinal flora were identified, with Verrucomicrobia and Akkermansia being the most prominent phylum and genus, respectively. These bacteria have strong anti-inflammatory and protective effects against S. uberis challenge. These data provide a foundation for further studies to elucidate gut flora function and exploration of therapeutic targets for mastitis.

Lactobacillus rhamnosus GG Colonization in Early Life Ameliorates Inflammaging of Offspring by Activating SIRT1/AMPK/PGC-1α Pathway

Inflammaging refers to chronic, low-grade inflammation during aging, which contributes to the pathogenesis of age-related diseases. Studies have shown that probiotic intervention in the aging stage could delay aging-related disorders. However, whether the application of probiotics in early life could have antiaging effects on offspring was unknown. Here, we investigated the effects of Lactobacillus rhamnosus GG (LGG) colonization in early life on inflammaging of offspring. Pregnant mice with the same conception time were given LGG live bacteria (LC group) or LGG fixed bacteria (NC group) from the 18th day after pregnancy until natural birth. The progeny mice were treated with 10⁷ cfu of live or fixed LGG for 0-5 days after birth, respectively. LGG colonization could be detected in the feces of 3-week offspring. The 16S rRNA sequencing analysis of 3-week-old offspring showed that colonization of LGG in early life could alter the composition and diversity of gut microbiota. Interestingly, the beneficial effects of LGG colonization in early life on the microbiota lasted to 8 months old. The abundance of longevity-related bacteria (Lactobacillus, Bifidobacterium, and Akkermansia muciniphila) increased significantly in the LGG colonization group. In addition, LGG colonization increased the abundance of short-chain fatty acid- (SCFA-) producing bacteria and the production of cecal SCFAs. LGG colonization in early life protected the intestinal barrier, enhanced antioxidant defense, attenuated epithelial cell DNA damage, and inhibited intestinal low-grade inflammation in 8-month-old progeny mice. Mechanically, LGG could upregulate Sirtuin1 (SIRT1)/Adenosine 5'-monophosphate-activated protein kinase (AMPK)/Peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) pathway and repress activation of nuclear factor-kappa B (NF-κB), while the protective effect of LGG was blunted after SIRT1 gene silencing. Together, LGG colonization in early life could ameliorate inflammaging of offspring, which would provide a new strategy for the prevention of age-related diseases.

Evaluation of the therapeutic effect and dose-effect of Bifidobacterium breve on the primary Clostridioides difficile infected mice

Probiotics are widely used as an adjuvant agent for the prevention of primary Clostridioides difficile infection (pCDI) and are less commonly used in the treatment of pCDI. Here, the different doses of Bifidobacterium breve YH68 were used to treat the pCDI mouse model and the actual therapeutic effect was evaluated. Fecal samples of pCDI mice were collected from the pre-infection, post-infection, and post-treatment stages. Simultaneous 16S rRNA amplicon sequencing and non-targeted metabolite assays were performed on these mouse feces, followed by correlation analysis. We found that high doses of B. breve YH68 exerted prominent therapeutic effects and no side effects in pCDI mice, resulted in a high survival rate, accompanied by a dose-effect relationship. YH68 enhanced the levels of caffeine, butyric acid, secondary bile acids in the feces of pCDI mice and significantly upregulated the abundance of genera associated with these metabolites, including Akkermansia, Coprococcus, Oscillospira, and Ruminococcus. Meanwhile, YH68 downregulated the levels of cortisol and phytosphingosine, and these metabolites were positively correlated with the abundance of the Klebsiella and Pseudomonas genera. These findings indicated that YH68 has outstanding therapeutic effects on the pCDI mouse model and is expected to be a potential new option for clinical pCDI therapy.Key points• Bifidobacterium breve YH68 has therapeutic effects on the pCDI mice and was accompanied by a dose-effect relationship.• Bifidobacterium breve YH68 enhanced the levels of caffeine, butyric acid, secondary bile acids in the feces of pCDI mice after treatment, as well as upregulated the abundance of beneficial microbes.• Bifidobacterium breve YH68 decreased the levels of cortisol and phytosphingosine and downregulated the abundance of harmful microbes.

Microbiome Crosstalk in Immunotherapy and Antiangiogenesis Therapy

The human body and its microbiome constitute a highly delicate system. The gut microbiome participates in the absorption of the host's nutrients and metabolism, maintains the microcirculation, and modulates the immune response. Increasing evidence shows that gut microbiome dysbiosis in the body not only affects the occurrence and development of tumors but also tumor prognosis and treatment. Microbiome have been implicated in tumor control in patients undergoing anti- angiogenesis therapy and immunotherapy. In cases with unsatisfactory responses to chemotherapy, radiotherapy, and targeted therapy, appropriate adjustment of microbes abundance is considered to enhance the treatment response. Here, we review the current research progress in cancer immunotherapy and anti- angiogenesis therapy, as well as the unlimited potential of their combination, especially focusing on how the interaction between intestinal microbiota and the immune system affects cancer pathogenesis and treatment. In addition, we discuss the effects of microbiota on anti-cancer immune response and anti- angiogenesis therapy, and the potential value of these interactions in promoting further research in this field.

Over-feeding the gut microbiome: A scoping review on health implications and therapeutic perspectives

The human gut microbiome has gained increasing attention over the past two decades. Several findings have shown that this complex and dynamic microbial ecosystem can contribute to the maintenance of host health or, when subject to imbalances, to the pathogenesis of various enteric and non-enteric diseases. This scoping review summarizes the current knowledge on how the gut microbiota and microbially-derived compounds affect host metabolism, especially in the context of obesity and related disorders. Examples of microbiome-based targeted intervention strategies that aim to restore and maintain an eubiotic layout are then discussed. Adjuvant therapeutic interventions to alleviate obesity and associated comorbidities are traditionally based on diet modulation and the supplementation of prebiotics, probiotics and synbiotics. However, these approaches have shown only moderate ability to induce sustained changes in the gut microbial ecosystem, making the development of innovative and tailored microbiome-based intervention strategies of utmost importance in clinical practice. In this regard, the administration of next-generation probiotics and engineered microbiomes has shown promising results, together with more radical intervention strategies based on the replacement of the dysbiotic ecosystem by means of fecal microbiota transplantation from healthy donors or with the introduction of synthetic communities specifically designed to achieve the desired therapeutic outcome. Finally, we provide a perspective for future translational investigations through the implementation of bioinformatics approaches, including machine and deep learning, to predict health risks and therapeutic outcomes.

Daily ingestion of Akkermansia mucciniphila for one month promotes healthy aging and increases lifespan in old female mice

The ingestion of certain probiotics has been suggested as a promising nutritional strategy to improve aging. The objective of this work was to evaluate the effects of the daily intake, for a month, of a new probiotic Akkermansia muciniphila (AKK) (2 × 10⁸ cfu/100µL PBS) on behavior, as well as function and redox state of immune cells of old female ICR-CD1 mice (OA group). For this, several behavioral tests were performed, and function and oxidative-inflammatory stress parameters of peritoneal leukocytes were analyzed in OA group, in a group of the same age that did not take AKK (old control, OC group) and in another adult control (AC) group. The results showed, in OA group, a significant improvement of several behavioral responses (coordination, balance, neuromuscular vigor, exploratory ability and anxiety like-behaviors), as well as in immune functions (chemotaxis, phagocytosis, NK activity and lymphoproliferation) and in oxidative stress parameters (glutathione peroxidase and reductase activities, oxidized glutathione and lipid oxidation concentrations) of the peritoneal leukocytes in comparison to those observed in OC group. In addition, peritoneal immune cells from the OA group released lower basal concentrations of pro-inflammatory cytokines (IL-2, IL-6 and TNF-α) compared to those from the OC group. The values of parameters in OA were similar to those in AC group. These improvements in the old mice receiving the probiotic were reflected in an increase in their lifespan. In conclusion, our data indicate that AKK supplementation for a short period could be a good nutritional strategy to promote healthy longevity.

Social isolation in adolescence and long-term changes in the gut microbiota composition and in the hippocampal inflammation: Implications for psychiatric disorders - Dirk Hellhammer Award Paper 2021

Exposure to early adverse experiences induces persistent changes in physiological, emotional and behavioural functions predisposing the individual to an enhanced vulnerability to develop different disorders during lifespan. The adverse outcomes depend upon the timing of the stressful experiences, and in this contest, adolescence represents a key sensitive period for brain development. Among the biological systems involved, gut microbiota has recently been proposed to act on the interplay between the stress response, brain functions and immune system, through the gut-brain axis communication. In the current study we aimed to evaluate, in a preclinical model, changes over time in the microbiota community structure in physiological condition and in response to stress during adolescence. We also aimed to correlate the microbiota composition to the inflammatory status in brain. We used the preclinical model of social deprivation in rats during adolescence, based on the lack of all social contacts, for four weeks after weaning, followed by re-socialization until adulthood. We collected fecal samples at different post-natal days to investigate the short- and long-lasting effects of social isolation on gut microbiota composition and we collected brain areas (dorsal and ventral hippocampus) samples at killing to measure a panel of inflammatory and microglia activation markers. 16 S metataxonomic sequencing analysis revealed that microbial changes were influenced by age in both isolated and controls rats, regardless of sex, whereas social isolation impacted the microbial composition in a sex-dependent manner. A multivariate analysis showed that social isolation induced short-term gut microbiota alterations in females but not in males. We also identified several stress-related genera associated with social isolation condition. In brain areas we found a specific inflammatory pattern, in dorsal and ventral hippocampus, that significantly correlated with gut microbiota composition. Overall, in this study we reported a novel sex-specific association between gut microbiota composition and inflammatory response related to social isolation paradigm during adolescence, suggesting that stressful experiences during this sensitive period could have a long-lasting impact on the development of different biological systems that could in turn influence the vulnerability to develop mental disorders later in life.

Akkermansia muciniphila Alleviates Dextran Sulfate Sodium (DSS)-Induced Acute Colitis by NLRP3 Activation

Akkermansia muciniphila has been proved to play a crucial role in the progression of colitis, but its underlying mechanism remains inconclusive. In this study, we aim to investigate the effect of A. muciniphila on the development of acute colitis and explore the underlying mechanism. We found that the fecal level of A. muciniphila was decreased in ulcerative colitis (UC) patients compared to the healthy people in the GMrepo database. Oral administration of A. muciniphila strain BAA-835 significantly ameliorated the symptoms in dextran sulfate sodium (DSS)-induced acute colitis, evidenced by decreased body weight loss, colon length shortening, and colon histological inflammatory score. In addition, the number of goblet cells and the mucin family were enhanced after A. muciniphila treatment. Furthermore, proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein 1 (MCP-1) had a downward trend. Mechanistically, the expression of NLRP3, caspase-1 p20, and IL-1β p17 were upregulated in A. muciniphila-treated mice. Additionally, the colon tissues from high-A. muciniphila UC patients had a higher NLRP3 expression than that from low-A. muciniphila UC patients. Moreover, the upregulation of NLRP3 was observed in mouse macrophage Raw264.7 cells and bone marrow-derived macrophage (BMDM) cells after incubation with A. muciniphila. To clarify whether the protective effect of A. muciniphila in colitis depends on NLRP3, we performed the NLRP3-deficient assay in NLRP3-/- mice in vivo. The evidence showed that NLRP3 deficiency eliminated the protective effects of A. muciniphila in acute colitis. In conclusion, A. muciniphila alleviates DSS-induced acute colitis by NLRP3 activation, which enriches the mechanism and provides a new prospect for the probiotic-based treatment of colitis. IMPORTANCE The gut microbiota and host immune response interaction influences the progression of intestinal inflammatory disease. As a well-recognized next-generation probiotic, Akkermansia muciniphila has been proved to play a crucial role in the progression of colitis, but its underlying mechanism remains inconclusive. We found that oral administration of A. muciniphila strain BAA-835 significantly ameliorated the symptoms of acute colitis. Mechanistically, the expression of NLRP3 was upregulated in the A. muciniphila group, and the protective effect of A. muciniphila in colitis depends on NLRP3 activation. This enriches the mechanism and provides a new prospect for the probiotic-based treatment of colitis, which would promote a deeper understanding of the complex characteristics of A. muciniphila and provide guidance for the treatment of human colitis in the future.

The Protective Effects of Live and Pasteurized Akkermansia muciniphila and Its Extracellular Vesicles against HFD/CCl4-Induced Liver Injury

Akkermansia muciniphila, as a member of the gut microbiota, has been proposed as a next-generation probiotic. Liver fibrosis is the main determinant of liver dysfunction and mortality in patients with chronic liver disease. In this study, we aimed to determine the beneficial effects of live and pasteurized A. muciniphila and its extracellular vesicles (EVs) on the prevention of liver fibrosis. The response of hepatic stellate cells (HSCs) to live and pasteurized A. muciniphila and its EVs was examined in quiescent, lipopolysaccharide (LPS)-activated LX-2 cells. Liver fibrosis was induced in 8-week-old C57BL/6 mice, using a high-fat diet (HFD) and carbon tetrachloride (CCl4) administration for 4 weeks. The mice were concomitantly treated via oral gavage with three forms of bacteria. The relative expression of different fibrosis and inflammatory markers was assessed in the tissues. Histological markers, serum biochemical parameters, and cytokine production were also analyzed, and their correlations with the relative abundance of targeted fecal bacteria were examined. All A. muciniphila preparations exhibited protective effects against HSC activation; however, EVs showed the greatest activity in HSC regression. Oral gavage with A. muciniphila ameliorated the serum biochemical and inflammatory cytokines and improved liver and colon histopathological damages. The relative expression of fibrosis and inflammatory biomarkers was substantially attenuated in the tissues of all treated mice. The composition of targeted stool bacteria in the live A. muciniphila group was clearly different from that in the fibrosis group. This study indicated that A. muciniphila and its derivatives could successfully protect against HFD/CCl4-induced liver injury. However, further studies are needed to prove the beneficial effects of A. muciniphila on the liver. IMPORTANCE Akkermansia muciniphila, as a member of the gut microbiota, has been proposed as a next-generation probiotic. Liver fibrosis is the main determinant of liver dysfunction and mortality in patients with chronic liver disease. In this study, we aimed to determine the beneficial effects of live and pasteurized A. muciniphila and its extracellular vesicles (EVs) on the prevention of liver fibrosis. The results of the present study indicated that oral administration of live and pasteurized A. muciniphila and its EVs could normalize the fecal targeted bacteria composition, improve the intestinal permeability, modulate inflammatory responses, and subsequently prevent liver injury in HFD/CCl4-administered mice. Following the improvement of intestinal and liver histopathology, HFD/CCl4-induced kidney damage and adipose tissue inflammation were also ameliorated by different A. muciniphila treatments.