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

Akkermansia muciniphila: A promising probiotic against inflammation and metabolic disorders

Metabolic disease is a worldwide epidemic that has become a public health problem. Gut microbiota is considered to be one of the important factors that maintain human health by regulating host metabolism. As an abundant bacterium in the host gut, A. muciniphila regulates metabolic and immune functions, and protects gut health. Multiple studies have indicated that alterations in the abundance of A. muciniphila are associated with various diseases, including intestinal inflammatory diseases, obesity, type 2 diabetes mellitus, and even parasitic diseases. Beneficial effects were observed not only in live A. muciniphila, but also in pasteurized A. muciniphila, A. muciniphila-derived extracellular vesicles, outer membrane, and secreted proteins. Although numerous studies have only proven the simple correlation between multiple diseases and A. muciniphila, an increasing number of studies in animal models and preclinical models have demonstrated that the beneficial impacts shifted from correlations to in-depth mechanisms. In this review, we provide a comprehensive view of the beneficial effects of A. muciniphila on different diseases and summarize the potential mechanisms of action of A. muciniphila in the treatment of diseases. We provide a comprehensive understanding of A. muciniphila for improving host health and discuss the perspectives of A. muciniphila in the future studies.

Differential gene expression in the kidneys of SHR and WKY rats after intravenous administration of Akkermansia muciniphila-derived extracellular vesicles

Although Akkermansia muciniphila (Am) plays a beneficial role as a probiotic in the treatment of metabolic syndrome, the mechanisms remain elusive. We tested the hypothesis that Am extracellular vesicles (AmEVs) protect against hypertension through modulation of gene expression in the kidneys of spontaneously hypertensive rats (SHRs). Extracellular vesicles purified from anaerobically cultured Am (1.0 × 108 or 1.0 × 109 particles/kg) or vehicles were injected into the tail veins of Wistar-Kyoto rats (WKYs) and SHRs weekly for 4 weeks. Renal cortical tissues isolated from both rat strains were analyzed by trichrome stain and RT-qPCR. AmEVs protect against the development of hypertension in SHRs without a serious adverse reaction. AmEVs increased the expression of vasocontracting Agt and At1ar as well as vasodilating At2r, Mas1 and Nos2 in the kidneys of both strains. These results indicate that AmEVs have a protective effect against hypertension without a serious adverse reaction. Therefore, it is foreseen that AmEVs may be utilized as a novel therapeutic for the treatment of hypertension.

Potential Probiotic Weizmannia coagulans WC10 Improved Antibiotic-Associated Diarrhea in Mice by Regulating the Gut Microbiota and Metabolic Homeostasis

Antibiotic-associated diarrhea (AAD) is a common side effect of long-term and heavy antibiotic therapy. Weizmannia coagulans (W. coagulans) is an ideal probiotic because of its high viability, stability, and numerous health benefits to the host. In this study, the strains were first screened for W. coagulans WC10 (WC10) with a high combined ability based on their biological properties of gastrointestinal tolerance, adhesion, and short-chain fatty acid production ability. The effect of WC10 on mice with AAD was further evaluated. The results showed that WC10 was effective in improving the symptoms of AAD, effectively restoring antibiotic-induced weight loss, and reducing diarrhea status score and fecal water content. In addition, WC10 decreased the expression of pro-inflammatory cytokines and increased the expression of anti-inflammatory cytokines, alleviated intestinal tissue damage and inflammation, and improved intestinal epithelial barrier function by decreasing serum levels of enterotoxin, DAO, and D-lactic acid, and by increasing the expression of the intestinal mucosal immune factors sIgA and occludin. Importantly, the composition and function of the gut microbiota gradually recovered after WC10 treatment, increasing the number of SCFAs-producing Bifidobacterium and Roseburia. Subsequently, the short-chain fatty acid (SCFA) content was examined and WC10 significantly increased acetate, propionate, and butyrate production. Additionally, metabolomic analysis also showed that WC10 reversed the antibiotic interference with major metabolic pathways. These findings provide a solid scientific basis for the future application of W. coagulans WC10 in the treatment of AAD.

Therapeutic Potential of Fungal Polysaccharides in Gut Microbiota Regulation: Implications for Diabetes, Neurodegeneration, and Oncology

This review evaluates the therapeutic effects of polysaccharides derived from mushroom species that have medicinal and edible properties. The fungal polysaccharides were recently studied, focusing on their modulation of the gut microbiota and their impact on various diseases. The study covers both clinical and preclinical studies, detailing the results and highlighting the significant influence of these polysaccharides on gut microbiota modulation. It discusses the potential health benefits derived from incorporating these polysaccharides into the diet for managing chronic diseases such as diabetes, neurodegenerative disorders, and cancer. Furthermore, the review emphasizes the interaction between fungal polysaccharides and the gut microbiota, underscoring their role in modulating the gut microbial community. It presents a systematic analysis of the findings, demonstrating the substantial impact of fungal polysaccharides on gut microbiota composition and function, which may contribute to their therapeutic effects in various chronic conditions. We conclude that the modulation of the gut microbiota by these polysaccharides may play a crucial role in mediating their therapeutic effects, offering a promising avenue for further research and potential applications in disease prevention and treatment.

Effect of inulin, galacto-oligosaccharides, and polyphenols on the gut microbiota, with a focus on Akkermansia muciniphila

Inulins, galacto-oligosaccharides (GOS) and polyphenols are considered to stimulate the growth of Akkermansia muciniphila (A. muciniphila) in the gut. We performed a meta-analysis of six microbiome studies (821 stool samples from 451 participants) to assess the effects of inulin, GOS, and polyphenols on the abundance of A. muciniphila in the gut. The intervention of GOS increased the relative abundance of A. muciniphila in healthy participants. Additionally, metabolic pathways associated with carbohydrate metabolism and short-chain fatty acid release were enriched following the GOS intervention. Furthermore, after the GOS intervention, the coexisting microbial communities of A. muciniphila, such as Eubacterium hallii and Bacteroides, exhibited an enhanced correlation with A. muciniphila. In conclusion, our findings suggest that GOS may promote the growth of A. muciniphila in the gut by modulating the gut microbiota composition.

Characterization and Preliminary Safety Evaluation of Akkermansia muciniphila PROBIO

In addition to providing certain health advantages to the host, a bacterial strain must possess a clearly defined safety profile to be regarded as a probiotic. In this study, we present a thorough and methodical assessment of the safety of a novel strain of bacteria, Akkermansia muciniphila PROBIO, which was isolated from human feces. Firstly, we examined the strain's overall features, such as its gastrointestinal tolerance and its physiological and biochemical traits. Next, we verified its genotoxic properties through bacterial reverse mutation and in vitro mammalian cell micronucleus assays. The drug sensitivity of A. muciniphila PROBIO was subsequently examined through an analysis of its antibiotic resistance genes. Additionally, the toxicological impact was verified through acute and sub-chronic toxicity studies. A genome-based safety assessment was conducted to gain further insights into gene function, including potential virulence factors and pathogenic properties. Finally, we assessed whether moxifloxacin resistance in A. muciniphila PROBIO is transferred using in vitro conjugation experiments. A. muciniphila PROBIO exhibited superior gastrointestinal tolerance, with no observed hematological or histopathological abnormalities. Moreover, the outcomes pertaining to mutagenic, clastogenic, or toxic impacts were found to be negative, even at exceedingly high dosages. Moreover, no adverse effects associated with the test substance were observed during the examination of acute and sub-chronic toxicity. Consequently, it was plausible to estimate the no-observed-adverse-effect level (NOAEL) to be 6.4 × 1011 viable bacteria for an average individual weighing 70 kg. Additionally, only three potential drug resistance genes and one virulence factor gene were annotated. A. muciniphila PROBIO is naturally resistant to moxifloxacin, and resistance does not transfer. Collectively, the data presented herein substantiate the presumed safety of A. muciniphila PROBIO for its application in food.

A Comprehensive Review of the Effects of Glycemic Carbohydrates on the Neurocognitive Functions Based on Gut Microenvironment Regulation and Glycemic Fluctuation Control

Improper glycemic carbohydrates (GCs) consumption can be a potential risk factor for metabolic diseases such as obesity and diabetes, which may lead to cognitive impairment. Although several potential mechanisms have been studied, the biological relationship between carbohydrate consumption and neurocognitive impairment is still uncertain. In this review, the main effects and mechanisms of GCs' digestive characteristics on cognitive functions are comprehensively elucidated. Additionally, healthier carbohydrate selection, a reliable research model, and future directions are discussed. Individuals in their early and late lives and patients with metabolic diseases are highly susceptible to dietary-induced cognitive impairment. It is well known that gut function is closely related to dietary patterns. Unhealthy carbohydrate diet-induced gut microenvironment disorders negatively impact cognitive functions through the gut-brain axis. Moreover, severe glycemic fluctuations, due to rapidly digestible carbohydrate consumption or metabolic diseases, can impair neurocognitive functions by disrupting glucose metabolism, dysregulating calcium homeostasis, oxidative stress, inflammatory responses, and accumulating advanced glycation end products. Unstable glycemic status can lead to more severe neurological impairment than persistent hyperglycemia. Slow-digested or resistant carbohydrates might contribute to better neurocognitive functions due to stable glycemic response and healthier gut functions than fully gelatinized starch and nutritive sugars.

Akkermansia muciniphila Ameliorates Alcoholic Liver Disease in Experimental Mice by Regulating Serum Metabolism and Improving Gut Dysbiosis

Alcoholic liver disease (ALD) represents a significant global health concern, yet the available treatment options remain limited. Numerous studies have shown that gut microbiota is a critical target for the treatment of ALD. Additionally, there is increasing evidence that host metabolism also plays a crucial role in the development of ALD. Akkermansia muciniphila has been demonstrated to ameliorate experimental ALD through its modulatory effects on the intestinal vascular barrier, enhancement of mucus layer thickness, and promotion of intestinal tight junction proteins. Nevertheless, there is a dearth of studies investigating the impact of A. muciniphila on host metabolism and gut microbiota. Here, C57BL/6 mice were utilized to establish a modified NIAAA model in order to investigate the impact of the oral administration of A. muciniphila during the development of ALD. Furthermore, we employed targeted metabolomics to analyze the serum metabolomic profiles of the mice and 2bRAD-M sequencing to comprehensively examine the underlying mechanisms of the efficacy of A. muciniphila on ALD. Our results illustrated that the oral administration of A. muciniphila alleviated alcohol-induced liver injury in conjunction with encouraged serum levels of ornithine and diminished the elevation of oxalic acid levels induced by alcohol intake. In addition, A. muciniphila also inhibited the proliferation of harmful bacteria, such as Escherichia coli and Helicobacter hepaticus, induced by alcohol consumption while promoting the growth of butyrate-producing and commensal bacteria, including Paramuribaculum intestinale and Bacteroides ovatus. In conclusion, this study suggests that A. muciniphila restores ALD by regulating the gut microbiota, and this corrective effect is associated with alterations in the serum metabolism. Our research supplies a theoretical basis for developing A. muciniphila as an innovative generation of probiotic for preventing and managing ALD.

A Two-Step Single Plex PCR Method for Evaluating Key Colonic Microbiota Markers in Young Mexicans with Autism Spectrum Disorders: Protocol and Pilot Epidemiological Application

Many neurological disorders have a distinctive colonic microbiome (CM) signature. Particularly, children with autism spectrum disorders (ASD) exhibit a very dissimilar CM when compared to neurotypical (NT) ones, mostly at the species level. Thus far, knowledge on this matter comes from high-throughput (yet very expensive and time-consuming) analytical platforms, such as massive high-throughput sequencing of bacterial 16S rRNA. Here, pure (260/280 nm, ~1.85) stool DNA samples (200 ng.µL^-1) from 48 participants [39 ASD, 9 NT; 3-13 y] were used to amplify four candidate differential CM markers [Bacteroides fragilis (BF), Faecalibacterium prausnitzii (FP), Desulfovibrio vulgaris (DV), Akkermansia muciniphila (AM)], using micro-organism-specific oligonucleotide primers [265 bp (BF), 198 bp (FP), 196 bp (DV), 327 bp (AM)] and a standardized two-step [low (step 1: °Tm-5 °C) to high (stage 2: °Tm-0 °C) astringent annealing] PCR protocol (2S-PCR). The method was sensitive enough to differentiate all CM biomarkers in the studied stool donors [↑ abundance: NT (BF, FP, AM), ASD (DV)], and phylogenetic analysis confirmed the primers' specificity.

Galactooligosaccharide or 2'-Fucosyllactose Modulates Gut Microbiota and Inhibits LPS/TLR4/NF-κB Signaling Pathway to Prevent DSS-Induced Colitis Aggravated by a High-Fructose Diet in Mice

A high-fructose diet (HFrD) has been reported to exacerbate dextran sulfate sodium (DSS)-induced colitis. 2'-Fucosyllactose (FL) and galactooligosaccharide (GOS) have been shown, respectively, to have preventive and ameliorative effects on colitis, while limited research has explored whether GOS and FL may be equally protective or preventive in mice with HFrD. Here, we evaluated the protective effects of FL and GOS on colitis exacerbated by feeding HFrD and explored the underlying mechanisms. DSS-induced colitis was studied in four randomized C57BL/6J male mice (n = 8 mice/group). Among them, three groups were fed with HFrD, and two received either GOS or FL treatment, respectively. Gut microbial composition was analyzed by 16S rDNA gene sequencing. Intestinal barrier integrity and inflammatory pathway expression were measured using qPCR, immunofluorescence, and Western blot methods. Compared to the HFrD group, GOS or FL treatment increased the α-diversity of the gut microbiota, reduced the relative abundance of Akkermansia, and increased the content of short-chain fatty acids (SCFAs), respectively. Compared with the HFrD group, GOS or FL treatment improved the loss of goblet cells and the reduction of tight junction protein expression, thereby improving intestinal barrier integrity. Also, GOS or FL inhibited the LPS/TLR4/NF-κB signaling pathway and oxidative stress to suppress the inflammatory cascade compared with the HFrD group. These findings suggest that GOS or FL intake can alleviate HFrD-exacerbated colitis, with no significant difference observed between GOS and FL treatments.

A Preliminary Study of Gut Microbiota in Airline Pilots: Comparison With Construction Workers and Fitness Instructors

INTRODUCTION

The term "WORKbiota" has been used to describe the impact of occupational exposure and work types on human microbiota composition. Airline pilots, construction workers, and fitness instructors encompass three diverse professional groups, each with distinct work environments and lifestyle factors that may significantly influence their intestinal "WORKbiota."

OBJECTIVES

The current preliminary investigation was aimed to compare the relative abundance of specific gut microbes among airline pilots, construction workers, and fitness instructors to shed light on any significant differences. By scrutinizing these diverse professional groups, our objective was to enhance our understanding of how occupational factors influence gut microbiota while identifying possible implications for occupational medicine.

METHODS

A convenience sample consisting of 60 men representing three different professional domains - airline pilots, construction workers, and fitness instructors (with 20 individuals in each group) - was selected during regular outpatient occupational health consultations. The abundance of selected gut microbiota constituents, including Escherichia coli, Methanobrevibacter smithii, Akkermansia muciniphila, Faecalibacterium prausnitzii, Lactobacillus spp., Bifidobacterium spp., and Bacteroides spp., was quantified using quantitative SYBR Green quantitative real-time polymerase chain reaction (qRT-PCR) in stool samples.

RESULTS

There were no significant variations among the groups concerning Escherichia coli, Methanobrevibacter smithii, Bifidobacterium spp., and Bacteroides spp. However, Lactobacillus spp. and Faecalibacterium prausnitzii were significantly more abundant in the microbiota of fitness instructors compared to both airline pilots and construction workers, with no significant differences observed between the latter two groups. Notably, the abundance of Akkermansia muciniphila demonstrated a progressive decline from fitness instructors to construction workers and ultimately to airline pilots, who exhibited the lowest levels.

CONCLUSION

Airline pilots' gut microbiota was characterized by a lower abundance of health-promoting bacterial species, including Lactobacillus spp., Faecalibacterium prausnitzii, and Akkermansia muciniphila. Future research is essential to determine whether targeted interventions, such as probiotic and prebiotic supplementation, could potentially enhance gut microbiota composition and overall health in particular occupational groups.

Exposing new taxonomic variation with inflammation - a murine model-specific genome database for gut microbiome researchers

BACKGROUND

The murine CBA/J mouse model widely supports immunology and enteric pathogen research. This model has illuminated Salmonella interactions with the gut microbiome since pathogen proliferation does not require disruptive pretreatment of the native microbiota, nor does it become systemic, thereby representing an analog to gastroenteritis disease progression in humans. Despite the value to broad research communities, microbiota in CBA/J mice are not represented in current murine microbiome genome catalogs.

RESULTS

Here we present the first microbial and viral genomic catalog of the CBA/J murine gut microbiome. Using fecal microbial communities from untreated and Salmonella-infected, highly inflamed mice, we performed genomic reconstruction to determine the impacts on gut microbiome membership and functional potential. From high depth whole community sequencing (~ 42.4 Gbps/sample), we reconstructed 2281 bacterial and 4516 viral draft genomes. Salmonella challenge significantly altered gut membership in CBA/J mice, revealing 30 genera and 98 species that were conditionally rare and unsampled in non-inflamed mice. Additionally, inflamed communities were depleted in microbial genes that modulate host anti-inflammatory pathways and enriched in genes for respiratory energy generation. Our findings suggest decreases in butyrate concentrations during Salmonella infection corresponded to reductions in the relative abundance in members of the Alistipes. Strain-level comparison of CBA/J microbial genomes to prominent murine gut microbiome databases identified newly sampled lineages in this resource, while comparisons to human gut microbiomes extended the host relevance of dominant CBA/J inflammation-resistant strains.

CONCLUSIONS

This CBA/J microbiome database provides the first genomic sampling of relevant, uncultivated microorganisms within the gut from this widely used laboratory model. Using this resource, we curated a functional, strain-resolved view on how Salmonella remodels intact murine gut communities, advancing pathobiome understanding beyond inferences from prior amplicon-based approaches. Salmonella-induced inflammation suppressed Alistipes and other dominant members, while rarer commensals like Lactobacillus and Enterococcus endure. The rare and novel species sampled across this inflammation gradient advance the utility of this microbiome resource to benefit the broad research needs of the CBA/J scientific community, and those using murine models for understanding the impact of inflammation on the gut microbiome more generally. Video Abstract.

Anti-diabetic effect of modified 'Guanximiyou' pummelo peel pectin on type 2 diabetic mice via gut microbiota

This study aimed to investigate the mechanisms of nature and modified 'Guanximiyou' pummelo peel pectin (GGP and MGGP) in alleviating T2DM through in vitro and in vivo. After modification, pectin was transformed from high methoxy pectin (HMP) to low methoxy pectin (LMP), and the content of galacturonic acid was increased. These made MGGP have stronger antioxidant capacity and better inhibition effect on corn starch digestion in vitro. In vivo experiments have shown that both GGP and MGGP inhibited the development of diabetes after 4 weeks of ingestion. However, MGGP can more effectively reduce blood glucose and regulate lipid metabolism, and has significant antioxidant capacity and the ability to promote SCFAs secretion. In addition, 16S rRNA analysis showed that MGGP changed the composition of intestinal microbiota in diabetic mice, decreased the abundance of Proteobacteria, and increased the relative abundance of Akkermansia, Lactobacillus, Oscillospirales and Ruminococcaceae. The phenotypes of the gut microbiome also changed accordingly, indicating that MGGP can inhibit the growth of pathogenic bacteria, alleviate intestinal functional metabolic disorders and reverse the potential risk of related complications. Altogether, our findings demonstrate that MGGP, as a dietary polysaccharide, may inhibit the development of diabetes by reversing the imbalance of gut microbiota.

Adult hypertensive rats are more prone to gut microflora perturbation and fibrosis in response to moderate restraint stress

Hypertension (HTN) is a common endpoint for numerous cardiovascular diseases, the prevalence of which has been quickly increasing due to a wide range of reasons. Previous research has found that following stress, ELISA and 16S rDNA sequencing indicated substantial changes in plasma cytokines or hormones, as well as alterations in gut microbiota in juvenile hypertensive rats. However, it remains still unclear how such interaction modifications affect microbial populations and organismal function. Stress-related hormones show a significant drop. Similar to earlier research, the stress group had dramatically increased release of pro-inflammatory cytokines such as IL-17. Importantly, a unified collection of tools that allows for deep and comprehensive colonic structural investigation has been developed. Stress may limit the transition of macrophages (Mφs) to M1Mφs while increasing the transfer to M2Mφs. Evidence highlighted that tight junction proteins were decreased along with enhancement in intestinal permeability. Morphological analysis revealed that the SHR-S group exhibited considerably higher levels of morphological alterations and fibrosis in colon, heart, and thoracic aorta tissues.Significant improvements in bacteria linked with short-chain fatty acid synthesis, such as Prevotella and Ruminococcus, were discovered by metagenomic analysis. Adult hypertensive rats are more susceptible to gut microbiota disruption and fibrosis as a result of mild restraint stress. This might contribute to some innovative ideas for HTN both treatment and prevention.

Oolong tea of different years protects high-fat diet-fed mice against obesity by regulating lipid metabolism and modulating the gut microbiota

Long-term stored oolong tea has recently attracted considerable attention concerning its salutary effect. In this study, the anti-obesity effect of different years' oolong tea on high-fat diet-fed mice was compared. Wuyi rock tea of 2001, 2011, and 2020 were chosen to be the representative samples of oolong tea. The results showed that eight-week administration of 2001 Wuyi rock tea (WRT01), 2011 Wuyi rock tea (WRT11), and 2020 Wuyi rock tea (WRT20) extracts (400 mg per kg per d) significantly decreased the body weight and attenuated the obesity in high-fat diet-fed mice. 2001 and 2011 Wuyi rock teas reduced obesity mainly through regulating lipid metabolism and activating the AMPK/SREBP-1 pathway, downregulating the expression of SREBP-1, FAS, and ACC and upregulating CPT-1a expression; while the 2011 and 2020 Wuyi rock teas by moderating the gut microbiota dysbiosis, reshaping the gut microbiota, and promoting the growth of beneficial bacteria, especially Akkermansia. 2011 Wuyi rock tea was proven to be more effective in reducing body weight gain and liver oxidative stress than the others. Collectively, all three Wuyi rock teas of different years alleviated high-fat diet-induced obesity by regulating lipid metabolism and modulating gut microbiota, whereas the emphasis of their internal mechanism is different with different storage ages.

Akkermansia muciniphila as a Next-Generation Probiotic in Modulating Human Metabolic Homeostasis and Disease Progression: A Role Mediated by Gut-Liver-Brain Axes?

Appreciation of the importance of Akkermansia muciniphila is growing, and it is becoming increasingly relevant to identify preventive and/or therapeutic solutions targeting gut-liver-brain axes for multiple diseases via Akkermansia muciniphila. In recent years, Akkermansia muciniphila and its components such as outer membrane proteins and extracellular vesicles have been known to ameliorate host metabolic health and intestinal homeostasis. However, the impacts of Akkermansia muciniphila on host health and disease are complex, as both potentially beneficial and adverse effects are mediated by Akkermansia muciniphila and its derivatives, and in some cases, these effects are dependent upon the host physiology microenvironment and the forms, genotypes, and strain sources of Akkermansia muciniphila. Therefore, this review aims to summarize the current knowledge of how Akkermansia muciniphila interacts with the host and influences host metabolic homeostasis and disease progression. Details of Akkermansia muciniphila will be discussed including its biological and genetic characteristics; biological functions including anti-obesity, anti-diabetes, anti-metabolic-syndrome, anti-inflammation, anti-aging, anti-neurodegenerative disease, and anti-cancer therapy functions; and strategies to elevate its abundance. Key events will be referred to in some specific disease states, and this knowledge should facilitate the identification of Akkermansia muciniphila-based probiotic therapy targeting multiple diseases via gut-liver-brain axes.

Kuqin ameliorates Lipopolysaccharide-induced acute lung injury by regulating indoleamine 2,3-dioxygenase 1 and Akkermansia muciniphila

Scutellariae radix (SR) has been proven to be highly effective in treating inflammation because of its superior medicinal properties. The two main commercial specifications of SR are Kuqin (KQ) and Ziqin (ZQ). According to traditional Chinese medicine theories, KQ has a better effect than ZQ on dispelling upper energizer lung damp heat, however, its mechanism of action is not known. Thus, this study investigated the role of KQ-induced alterations in endogenous metabolites and gut microbiota in regulating LPS-induced acute lung injury (ALI). KQ treatment ameliorated lung injury more effectively than ZQ and demonstrated satisfactory organ protection properties. KQ treatment reversed the tryptophan metabolite abnormalities in ALI and reshaped the composition of gut microbial communities. Additionally, the abundance of the enriched Akkermansia muciniphila was significantly and inversely correlated with the rate-limiting enzyme of the tryptophan/kynurenine pathway, indoleamine 2,3-dioxygenase 1 (IDO1) activity (p = 0.0214, R² =0.7712). Furthermore, the beneficial and causative effects of A. muciniphila were confirmed by antibiotic and microbial intervention experiments. Live and pasteurized A. muciniphila, both supplements could ameliorate the inflammatory response and down-regulate IDO1 expression, thereby restoring tryptophan metabolic imbalance. In conclusion, the current study demonstrated for the first time that KQ may act on the A. muciniphila abundance, regulate IDO1 activity, and thus ameliorate ALI. Interestingly, A. muciniphila supplementation could be a promising therapeutic option for lung diseases through the gut-lung axis.

Capsaicin shapes gut microbiota and pre-metastatic niche to facilitate cancer metastasis to liver

Dietary factors are fundamental in tumorigenesis throughout our lifetime. A spicy diet has been ambiguous on the development of cancers, especially in the study of colon cancer metastasis. Here, we utilized a mouse metastasis model to test the potential role of capsaicin in influencing metastasis. Long-term continuous administration of capsaicin diet (300 mg/kg) to mice promotes the formation of liver pre-metastatic niche to facilitate the metastasis of colon cancer cells. Bacteria translocation to liver is clearly observed. Capsaicin increases intestinal barrier permeability and disrupts gut vascular barrier by altering the composition of gut microbiota. Capsaicin not only changes the abundance of mucin-related bacteria like Akkermanisa and Muribaculaceae, but also bacteria involved in bile acids metabolism. Dysregulated bile acids profile is related to the recruitment of natural killer T (NKT) cells in pre-metastatic niche, primary bile acid α-Muricholic acid can enhance the recruitment of NKT cells, while secondary bile acids Glycoursodeoxycholic acid and Taurohyodeoxycholic acid impair the recruitment of NKT cells. These findings reveal long term consumption of capsaicin increases the risk of cancer metastasis through modulating the gut microbiota. Capsaicin (300 mg/kg) disrupts gut barrier and promotes the translocation of bacteria to liver, while altered bile acids metabolism affects the recruitment of NKT cells in liver, forming a pre-metastatic niche and promoting cancer metastasis.

Flos Puerariae-Semen Hoveniae medicinal pair extract ameliorates DSS-induced inflammatory bowel disease through regulating MAPK signaling and modulating gut microbiota composition

Background: Inflammatory bowel disease (IBD) is a global gastrointestinal disease characterized by relapsing and remitting inflammatory conditions. Flos Puerariae (the flower of Pueraria lobata [Willd.] Ohwi and P. thomsonii Benth.) and Hovenia dulcis Thunb. (Rhamnaceae) are traditional Chinese medicines. This medicinal pair has been used to treat various diseases due to its excellent anti-oxidant and anti-inflammatory activity. However, the effects of extracts from these plants on dextran sulfate sodium (DSS)-induced colitis have not been investigated; further study is needed to improve the understanding of their mechanisms of action and potential applications. Methods: The chemical constitution of extracts from Flos Puerariae and Semen Hoveniae (PHE) was analyzed using UPLC-LTQ-Orbitrap-MS/MS. The protective effects of PHE on mice with DSS-induced colitis were evaluated through assessment of body weight loss, disease activity index (DAI) score, colon length shortening, and pathological changes. The levels of inflammatory cytokines were determined by ELISA and RT-qPCR. Biomarkers of oxidative stress (ROS, CAT, SOD, MDA, and T-AOC) were analyzed using biochemical kits. The expression of MAPK proteins was determined by Western blotting analysis. Gut microbiota were analyzed via 16S rRNA sequencing. Results: Chemical composition analysis indicated that PHE contains various bioactive compounds, including puerarin, kakkalide, tectoridin, and genistin. The findings from this study suggest that PHE could effectively modulate histopathological score, inflammatory cell infiltration, and inflammatory factor secretion. Notably, PHE ameliorated oxidative stress by inhibiting activation of the MAPK pathway, leading to decreased inflammatory mediators and restored antioxidant enzyme activity. Furthermore, PHE treatment regulated the composition of the gut microbiota by increasing the abundance of benign bacteria, such as Akkermansia, and reducing the abundance of harmful bacteria, such as Proteobacteria. Conclusion: The findings from this study demonstrate the mechanism underlying the amelioration of DSS-induced intestinal oxidative stress by PHE and its positive impact on the restoration of the composition of gut microbiota.

2'-Fucosyllactose Promotes the Production of Short-Chain Fatty Acids and Improves Immune Function in Human-Microbiota-Associated Mice by Regulating Gut Microbiota

As a natural prebiotic in human milk, 2'-fucosyllactose (2'-FL) is actively used in infant formula (IF). However, the 2'-FL influence on the improvement of gut microbiota and the regulation of the immune function remains unknown. In this study, human microbiota-associated (HMA) mice were used to demonstrate that feeding 2'-FL-containing IF was comparable to human milk at levels of immune cytokines (IL-2, IL-9, IL-10, and sIgA) and short-chain fatty acids (SCFAs, i.e., acetate and propionate). In addition, 2'-FL increased the abundance of Blautia and Olsenella and improved the anti-inflammatory cytokine IL-10 levels. The abundance of Blautia and Olsenella positively correlated with the IL-10 levels. 2'-FL also decreased the abundance of Enterorhabdus and Lachnospiraceae_UCG-006 and elevated SCFA levels, showing a negative correlation between these genera and SCFAs. Our findings revealed that feeding 2'-FL-containing IF drives the levels of cytokines and SCFAs toward human milk levels by shaping the beneficial gut microbiota profile.

Novel Candidate Microorganisms for Fermentation Technology: From Potential Benefits to Safety Issues

Fermentation is one of the oldest known production processes and the most technologically valuable in terms of the food industry. In recent years, increasing nutrition and health awareness has also changed what is expected from fermentation technology, and the production of healthier foods has started to come a little more forward rather than increasing the shelf life and organoleptic properties of foods. Therefore, in addition to traditional microorganisms, a new generation of (novel) microorganisms has been discovered and research has shifted to this point. Novel microorganisms are known as either newly isolated genera and species from natural sources or bacterial strains derived from existing bacteria. Although novel microorganisms are mostly studied for their use in novel food production in terms of gut-microbiota modulation, recent innovative food research highlights their fermentative effects and usability, especially in food modifications. Herein, Clostridium butyricum, Bacteroides xylanisolvens, Akkermansia muciniphila, Mycobacterium setense manresensis, and Fructophilic lactic acid bacteria (FLAB) can play key roles in future candidate microorganisms for fermentation technology in foods. However, there is also some confusion about the safety issues related to the use of these novel microorganisms. This review paper focuses on certain novel candidate microorganisms for fermentation technology with a deep view of their functions, benefits, and safety issues.

The gut microbiota and celiac disease: Pathophysiology, current perspective and new therapeutic approaches

Celiac disease (CD) as a chronic gluten-sensitive intestinal condition, mainly affects genetically susceptible hosts. The primary determinants of CD have been identified as environmental and genetic variables. The development of CD is significantly influenced by environmental factors, including the gut microbiome. Therefore, gut microbiome re-programming-based therapies using probiotics, prebiotics, postbiotics, gluten-free diet, and fecal microbiota transplantation have shown promising results in the modification of the gut microbiome. Due to the importance and paucity of information regarding the CD pathophysiology, in this review, we have covered the association between CD development and gut microbiota, the effects of infectious agents, particularly the recent Covid-19 infection in CD patients, and the efficacy of potential therapeutic approaches in the CD have been discussed. Hence, scientific literature indicates that the diverse biological functions of the gut microbiota against immunomodulatory responses have made microbiome-based therapy an alternative therapeutic paradigm to ameliorate the symptoms of CD and quality of life. However, the exact potential of microbiota-based techniques that aims to quantitatively and qualitatively alter the gut microbiota to be used in the treatment and ameliorate the symptoms of CD will be determined with further research in the future.

The potential impact of a probiotic: Akkermansia muciniphila in the regulation of blood pressure—the current facts and evidence

Akkermansia muciniphila (A. muciniphila) is present in the human gut microbiota from infancy and gradually increases in adulthood. The potential impact of the abundance of A. muciniphila has been studied in major cardiovascular diseases including elevated blood pressure or hypertension (HTN). HTN is a major factor in premature death worldwide, and approximately 1.28 billion adults aged 30–79 years have hypertension. A. muciniphila is being considered a next-generation probiotic and though numerous studies had highlighted the positive role of A. muciniphila in lowering/controlling the HTN, however, few studies had highlighted the negative impact of increased abundance of A. muciniphila in the management of HTN. Thus, in the review, we aimed to discuss the current facts, evidence, and controversy about the role of A. muciniphila in the pathophysiology of HTN and its potential effect on HTN management/regulation, which could be beneficial in identifying the drug target for the management of HTN.

Neonatal Morphine Results in Long-Lasting Alterations to the Gut Microbiome in Adolescence and Adulthood in a Murine Model

Despite the many advancements in the field of pain management, the use of intravenous opioids, such as morphine, in neonates is still a challenge for clinicians and researchers, as the available evidence concerning the long-term consequences of such an early exposure is limited. In particular, little is known concerning the long-term consequences of neonatal morphine exposure on the gut microbiome, which has been identified as a key modulator of health and diseases. Consequently, the purpose of this study was to investigate those long-term consequences of neonatal morphine on the gut microbiome. Newborn mice were exposed to either morphine (5 mg/kg/day) or saline for a duration of 7 ± 2 days. Fecal samples were collected during adolescence and adulthood to longitudinally assess the gut microbiome. DNA extracted from the stool samples were sent out for 16s rRNA sequencing. During adolescence, neonatal morphine resulted in a significant increase of α-diversity and an overall decrease in the abundance of several commensal genera. During adulthood, β-diversity revealed a significantly different microbial composition of the neonatally morphine-exposed mice than that of the controls. The results demonstrate that morphine exposure during this critical developmental period resulted in long-lasting changes, particularly a reduction in several commensal bacteria. Thus, an adjunct therapeutic intervention with probiotics could potentially be used along with opioids to manage pain while attenuating the long-term co-morbidities of neonatal morphine later in life.

Structural characteristics and immunostimulatory activity of sea cucumber tendon polysaccharides in cyclophosphamide-induced Balb/c mice

Sea cucumber tendon, one of the main parts of sea cucumber viscera, is widely accepted as a waste residue. In this study, a sea cucumber tendon polysaccharide (SCTPII) was purified from sea cucumber tendons and its primary structures and immunomodulatory activity were investigated. SCTPII is a triple-helix conformation homogeneous polysaccharide with a molecular weight of 3.97 × 10⁶ Da that consists of glucose and fucose with molar ratios of 92.09% and 7.91% with high thermostability. In vivo tests on immunosuppressed Balb/c mice revealed that compared with the model group, the proliferation of T cells and B cells in splenic lymphocytes of mice in the high-dose group was significantly improved by 0.92 times and 5.14 times, respectively. Additionally, SCTPII could improve the proliferation ability and phagocytosis of macrophages, as well as promoting the expression of IL-6, TNF-α and IFN-γ and enhancing the intestinal physical barrier function by increasing the protein expression of claudin-1, occludin, ZO-1 and MUC2. Furthermore, the 16S rRNA sequencing of fecal samples was performed, and gene count and α-diversity analysis revealed that SCTPs could improve the microbial community richness. In particular, SCTPs could increase the relative abundance of Lactobacillus, Bacteroides and Akkermansia and reduce the relative abundance of Lachnospiraceae_NK4A136_group and Rikenellaceae_RC9_gut_group. These results demonstrate that SCPII possesses potential immunoregulatory activities in cyclophosphamide-induced mice by regulating intestinal microbiota diversity and improving immune organs, enhancing the proliferation ability of macrophages and splenocyte proliferation, and enhancing intestinal physical barrier function, which might provide important evidence for the development and utilization of the viscera of sea cucumber.

Litchi-Derived Polyphenol Alleviates Liver Steatosis and Gut Dysbiosis in Patients with Non-Alcoholic Fatty Liver Disease: A Randomized Double-Blinded, Placebo-Controlled Study

Preclinical data suggest the role of litchi extract in alleviating non-alcoholic fatty liver disease (NAFLD) by modulating gut microbiota. We aimed at investigating whether oligonol, a litchi-derived polyphenol, could improve liver steatosis and gut dysbiosis in patients with NAFLD. Adults with grade ≥2 steatosis, defined by an MRI proton density fat fraction (MRI-PDFF) of ≥11%, were randomly assigned to receive either oligonol or placebo for 24 weeks. The alteration in the MRI-PDFF and gut microbiota composition assessed by 16S ribosomal RNA sequencing were examined. There were 38 patients enrolled (n = 19 in each group). A significant reduction in the MRI-PDFF between week 0 and week 24 was observed in the oligonol group, while there was a non-significant decrease in the placebo group. A significant improvement in alpha-diversity was demonstrated in both of the groups. The oligonol-induced microbiota changes were characterized by reduced abundance of pathogenic bacteria, including Dorea, Romboutsia, Erysipelotrichaceae UCG-003 and Agathobacter, as well as increased abundance of short-chain fatty acids (SCFAs)-producing bacteria, such as Akkermansia, Lachnospira, Dialister and Faecalibacterium. In summary, this study is the first to provide evidence that supports that oligonol improves steatosis through the modulation of gut bacterial composition. Our results also support the beneficial and complementary role of oligonol in treating NAFLD.

The Gut Microbiota and Vascular Aging: A State-of-the-Art and Systematic Review of the Literature

The gut microbiota is a critical regulator of human physiology, deleterious changes to its composition and function (dysbiosis) have been linked to the development and progression of cardiovascular diseases. Vascular ageing (VA) is a process of progressive stiffening of the arterial tree associated with arterial wall remodeling, which can precede hypertension and organ damage, and is associated with cardiovascular risk. Arterial stiffness has become the preferred marker of VA. In our systematic review, we found an association between gut microbiota composition and arterial stiffness, with two patterns, in most animal and human studies: a direct correlation between arterial stiffness and abundances of bacteria associated with altered gut permeability and inflammation; an inverse relationship between arterial stiffness, microbiota diversity, and abundances of bacteria associated with most fit microbiota composition. Interventional studies were able to show a stable link between microbiota modification and arterial stiffness only in animals. None of the human interventional trials was able to demonstrate this relationship, and very few adjusted the analyses for determinants of arterial stiffness. We observed a lack of large randomized interventional trials in humans that test the role of gut microbiota modifications on arterial stiffness, and take into account BP and hemodynamic alterations.

Postbiotics as the new frontier in food and pharmaceutical research

Food is the essential need of human life and has nutrients that support growth and health. Gastrointestinal tract microbiota involves valuable microorganisms that develop therapeutic effects and are characterized as probiotics. The investigations on appropriate probiotic strains have led to the characterization of specific metabolic byproducts of probiotics named postbiotics. The probiotics must maintain their survival against inappropriate lethal conditions of the processing, storage, distribution, preparation, and digestion system so that they can exhibit their most health effects. Conversely, probiotic metabolites (postbiotics) have successfully overcome these unfavorable conditions and may be an appropriate alternative to probiotics. Due to their specific chemical structure, safe profile, long shelf-life, and the fact that they contain various signaling molecules, postbiotics may have anti-inflammatory, immunomodulatory, antihypertensive properties, inhibiting abnormal cell proliferation and antioxidative activities. Consequently, present scientific literature approves that postbiotics can mimic the fundamental and clinical role of probiotics, and due to their unique characteristics, they can be applied in an oral delivery system (pharmaceutical/functional foods), as a preharvest food safety hurdle, to promote the shelf-life of food products and develop novel functional foods or/and for developing health benefits, and therapeutic aims. This review addresses the latest postbiotic applications with regard to pharmaceutical formulations and commercial food-based products. Potential postbiotic applications in the promotion of host health status, prevention of disease, and complementary treatment are also reviewed.