Probiotics modulated gut microbiota suppresses hepatocellular carcinoma growth in mice

Gut microbial dysbiosis associates hepatocellular carcinoma via the gut-liver axis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. Gut microbiota has been demonstrated to play a critical role in liver inflammation, chronic fibrosis, liver cirrhosis, and HCC development through the gut-liver axis.

DATA SOURCES

Recently there have been several innovative studies investigating gut microbial dysbiosis-mediated enhancement of HCC through the gut-liver axis. Literatures from January 1998 to January 2018 were searched in the PubMed database using the keywords "gut microbiota" and "hepatocellular carcinoma" or "liver cancer", and the results of experimental and clinical studies were analyzed.

RESULTS

Gut microbial dysbiosis accompanies the progression of alcoholic liver disease, non-alcoholic fatty liver disease and liver cirrhosis, and promotes HCC progression in an experimental mouse model. The immune system and key factors such as Toll-like receptor 4 are involved in the process. There is evidence for gut microbial dysbiosis in hepatitis virus-related HCC patients.

CONCLUSIONS

Gut microbial dysbiosis is closely associated with hepatic inflammation disease and HCC through the gut-liver axis. With the enhanced understanding of the interactions between gut microbiota and liver through the gut-liver axis, new treatment strategies for HCC are being developed.

Antibiotic Treatment Drives the Diversification of the Human Gut Resistome

Despite the documented antibiotic-induced disruption of the gut microbiota, the impact of antibiotic intake on strain-level dynamics, evolution of resistance genes, and factors influencing resistance dissemination potential remains poorly understood. To address this gap we analyzed public metagenomic datasets from 24 antibiotic treated subjects and controls, combined with an in-depth prospective functional study with two subjects investigating the bacterial community dynamics based on cultivation-dependent and independent methods. We observed that short-term antibiotic treatment shifted and diversified the resistome composition, increased the average copy number of antibiotic resistance genes, and altered the dominant strain genotypes in an individual-specific manner. More than 30% of the resistance genes underwent strong differentiation at the single nucleotide level during antibiotic treatment. We found that the increased potential for horizontal gene transfer, due to antibiotic administration, was ∼3-fold stronger in the differentiated resistance genes than the non-differentiated ones. This study highlights how antibiotic treatment has individualized impacts on the resistome and strain level composition, and drives the adaptive evolution of the gut microbiota.

Targeting gut microbiota with dietary components on cancer: Effects and potential mechanisms of action

Cancers are common chronic diseases worldwide and cause severe health burdens. There have been ongoing debates on the role of gut microbiota in the prevention and management of cancers, thus, it is worthwhile to pay high attention to the impacts of gut microbiota on several cancers, such as colon, liver, and breast cancers. In addition, it has been reported that gut microbiota may also affect the efficacy of cancer chemotherapy and immunotherapy. Among all the factors that influence gut microbiota, diet is the most influential and modifiable. The prebiotics, dietary fibers, short-chain fatty acids, and other bioactive compounds are all important dietary components to assist the growth of beneficial microbiota in the gut, which can protect against cancers and promote human health. Their beneficial effects can be due to the fermentation of dietary fibers, the metabolism of phytochemicals, the synthesis of estrogens, and interactions with chemotherapies and immunotherapies. In order to provide updated information of the relationships among dietary components, gut microbiota, and cancer, in this review, we summarize the reciprocal interactions between dietary components and gut microbiota, and highlight the impacts of dietary components on several common cancers by targeting gut microbiota, with the potential mechanisms of actions also intensively discussed. As a result, this review can be very helpful for healthy people as well as cancer patients to prevent or manage cancers via dietary factor-mediated regulation of gut microbiota.

Protection of hepatocyte mitochondrial function by blueberry juice and probiotics via SIRT1 regulation in non-alcoholic fatty liver disease

Blueberry juice and probiotics improves mitochondrial dysfunction and oxidative stress induced by nonalcoholic fatty liver disease (NAFLD), by modulating the SIRT1 pathway.

Hepatocellular Carcinoma Is Associated With Gut Microbiota Profile and Inflammation in Nonalcoholic Fatty Liver Disease

The gut-liver axis plays a pivotal role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD), which is the third leading cause of hepatocellular carcinoma (HCC) worldwide. However, the link between gut microbiota and hepatocarcinogenesis remains to be clarified. The aim of this study was to explore what features of the gut microbiota are associated with HCC in patients with cirrhosis and NAFLD. A consecutive series of patients with NAFLD-related cirrhosis and HCC (group 1, 21 patients), NAFLD-related cirrhosis without HCC (group 2, 20 patients), and healthy controls (group 3, 20 patients) was studied for gut microbiota profile, intestinal permeability, inflammatory status, and circulating mononuclear cells. We finally constructed a model depicting the most relevant correlations among these features, possibly involved in hepatocarcinogenesis. Patients with HCC showed increased levels of fecal calprotectin, while intestinal permeability was similar to patients with cirrhosis but without HCC. Plasma levels of interleukin 8 (IL8), IL13, chemokine (C-C motif) ligand (CCL) 3, CCL4, and CCL5 were higher in the HCC group and associated with an activated status of circulating monocytes. The fecal microbiota of the whole group of patients with cirrhosis showed higher abundance of Enterobacteriaceae and Streptococcus and a reduction in Akkermansia. Bacteroides and Ruminococcaceae were increased in the HCC group, while Bifidobacterium was reduced. Akkermansia and Bifidobacterium were inversely correlated with calprotectin concentration, which in turn was associated with humoral and cellular inflammatory markers. A similar behavior was also observed for Bacteroides. Conclusion: Our results suggest that in patients with cirrhosis and NAFLD the gut microbiota profile and systemic inflammation are significantly correlated and can concur in the process of hepatocarcinogenesis.

Microbial Ecology of Fermented Vegetables and Non-Alcoholic Drinks and Current Knowledge on Their Impact on Human Health

Fermented foods are currently experiencing a re-discovery, largely driven by numerous health benefits claims. While fermented dairy, beer, and wine (and other alcoholic fermented beverages) have been the subject of intensive research, other plant-based fermented foods that are in some case widely consumed (kimchi/sauerkraut, pickles, kombucha) have received less scientific attention. In this chapter, the current knowledge on the microbiology and potential health benefits of such plant-based fermented foods are presented. Kimchi is the most studied, characterized by primarily acidic fermentation by lactic acid bacteria. Anti-obesity and anti-hypertension properties have been reported for kimchi and other pickled vegetables. Kombucha is the most popular non-alcoholic fermented drink. Kombucha's microbiology is remarkable as it involves all fermenters described in known fermented foods: lactic acid bacteria, acetic acid bacteria, fungi, and yeasts. While kombucha is often hyped as a "super-food," only antioxidant and antimicrobial properties toward foodborne pathogens are well established; and it is unknown if these properties incur beneficial impact, even in vitro or in animal models. The mode of action that has been studied and demonstrated the most is the probiotic one. However, it can be expected that fermentation metabolites may be prebiotic, or influence host health directly. To conclude, plant-based fermented foods and drinks are usually safe products; few negative reports can be found, but more research, especially human dietary intervention studies, are warranted to substantiate any health claim.

Microbiome and bile acid profiles in duodenal aspirates from patients with liver cirrhosis: The Microbiome, Microbial Markers and Liver Disease Study

AIM

Cirrhosis is a leading cause of death worldwide, yet there are no well-established risk stratifying tools for lethal complications, including hepatocellular carcinoma (HCC). Patients with liver cirrhosis undergo routine endoscopic surveillance, providing ready access to duodenal aspirate samples that could be a source for identifying novel biomarkers. The aim of this study was to characterize the microbiome and bile acid profiles in duodenal aspirates from patients with liver cirrhosis to assess the feasibility of developing biomarkers for HCC risk stratification.

METHODS

Thirty patients with liver cirrhosis were enrolled in the Microbiome, Microbial Markers, and Liver Disease study between May 2015 and March 2017. Detailed clinical and epidemiological data were collected at baseline and at 6-monthly follow-up visits. Duodenal aspirate fluid was collected at baseline for microbial characterization using 16S ribosomal RNA sequencing and bile acid quantification using mass spectroscopy.

RESULTS

Alcohol-related cirrhosis was associated with reductions in the Bacteroidetes phylum, particularly Prevotella (13-fold reduction), and expansion of Staphylococcus (13-fold increase), compared to hepatitis C virus-related cirrhosis. Participants with hepatic encephalopathy (HE) had less microbial diversity compared to patients without HE (P < 0.05), and were characterized by expansion of Mycobacterium (45-fold increase) and Gram-positive cocci including Granulicatella (3.1-fold increase), unclassified Planococcaceae (3.3-fold increase), and unclassified Streptococcaceae (4.5-fold increase). Non-Hispanic White patients had reduced microbial richness (P < 0.01) and diversity (P < 0.05), and increased levels of conjugated ursodeoxycholic acid (glycoursodeoxycholic acid and tauroursodeoxycholic acid, P < 0.05) compared to Hispanic patients.

CONCLUSION

Microbial profiles of duodenal aspirates differed by cirrhosis etiology, HE, and Hispanic ethnicity.

Publisher Correction: The gut-liver axis and the intersection with the microbiome

In the original version of Table 1 published online, upward arrows to indicate increased translocation of PAMPs were missing from the row entitled 'Translocation' for both the column on alcoholic liver disease and nonalcoholic fatty liver disease. This error has now been updated in the PDF and HTML version of the article.

Rice straw biochar as a novel niche for improved alterations to the cecal microbial community in rats

Biochar as additive has been shown positive effect in animal production, which may be linked to the role of gastrointestinal microbial modulation. This study aimed to assess the effects of biochar on the gut microbial communities in terms of their structure and diversity. Illumina high-throughput technology was utilized to evaluate the cecal microbial community in Wistar rats received oral rice straw biochar (RSB) at 1120 mg/kg of body weight for 5 weeks. RSB improved the gut mucosal structure and epithelial integrity. More importantly, principal coordinate analysis of UniFrac distances based on a 97% operational taxonomic unit composition and abundance indicated that the bacterial community was ameliorated after RSB addition (P < 0.05). Firmicutes and Bacteroidetes were found to be the prevalent phyla accounting for approximately 90% of the sequences and their ratio of relative abundance was increased by RSB addition (P < 0.05). Improved bacterial proportion of unclassified Lachnospiraceae (P < 0.001), Oscillibacter (P = 0.02), and Clostridium IV (P = 0.02) and XIVa (P = 0.02) as well as decreased abundances of Prevotella (P < 0.001) and Bacteroides (P = 0.03) were also detected at genus level following RSB treatment. These results revealed that RSB altered and improved the cecal microbial community, which may contribute to the affected growth and gut status in rats.

Physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth

Biofilm formation is initiated by adhesion of individual bacteria to a surface. However, surface adhesion alone is not sufficient to form the complex community architecture of a biofilm. Surface-sensing creates bacterial awareness of their adhering state on the surface and is essential to initiate the phenotypic and genotypic changes that characterize the transition from initial bacterial adhesion to a biofilm. Physico-chemistry has been frequently applied to explain initial bacterial adhesion phenomena, including bacterial mass transport, role of substratum surface properties in initial adhesion and the transition from reversible to irreversible adhesion. However, also emergent biofilm properties, such as production of extracellular-polymeric-substances (EPS), can be surface-programmed. This review presents a four-step, comprehensive description of the role of physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth: (1) bacterial mass transport towards a surface, (2) reversible bacterial adhesion and (3) transition to irreversible adhesion and (4) cell wall deformation and associated emergent properties. Bacterial transport mostly occurs from sedimentation or convective-diffusion, while initial bacterial adhesion can be described by surface thermodynamic and Derjaguin-Landau-Verwey-Overbeek (DLVO)-analyses, considering bacteria as smooth, inert colloidal particles. DLVO-analyses however, require precise indication of the bacterial cell surface, which is impossible due to the presence of bacterial surface tethers, creating a multi-scale roughness that impedes proper definition of the interaction distance in DLVO-analyses. Application of surface thermodynamics is also difficult, because initial bacterial adhesion is only an equilibrium phenomenon for a short period of time, when bacteria are attached to a substratum surface through few surface tethers. Physico-chemical bond-strengthening occurs in several minutes leading to irreversible adhesion due to progressive removal of interfacial water, conformational changes in cell surface proteins, re-orientation of bacteria on a surface and the progressive involvement of more tethers in adhesion. After initial bond-strengthening, adhesion forces arising from a substratum surface cause nanoscopic deformation of the bacterial cell wall against the elasticity of the rigid peptidoglycan layer positioned in the cell wall and the intracellular pressure of the cytoplasm. Cell wall deformation not only increases the contact area with a substratum surface, presenting another physico-chemical bond-strengthening mechanism, but is also accompanied by membrane surface tension changes. Membrane-located sensor molecules subsequently react to control emergent phenotypic and genotypic properties in biofilms, most notably adhesion-associated ones like EPS production. Moreover, also bacterial efflux pump systems may be activated or mechano-sensitive channels may be opened upon adhesion-induced cell wall deformation. The physico-chemical properties of the substratum surface thus control the response of initially adhering bacteria and through excretion of autoinducer molecules extend the awareness of their adhering state to other biofilm inhabitants who subsequently respond with similar emergent properties. Herewith, physico-chemistry is not only involved in initial bacterial adhesion to surfaces but also in what we here propose to call "surface-programmed" biofilm growth. This conclusion is pivotal for the development of new strategies to control biofilm formation on substratum surfaces, that have hitherto been largely confined to the initial bacterial adhesion phenomena.

Contribution of the commensal microbiota to atherosclerosis and arterial thrombosis

The commensal gut microbiota is an environmental factor that has been implicated in the development of cardiovascular disease. The development of atherosclerotic lesions is largely influenced not only by the microbial-associated molecular patterns of the gut microbiota but also by the meta-organismal trimethylamine N-oxide pathway. Recent studies have described a role for the gut microbiota in platelet activation and arterial thrombosis. This review summarizes the results from gnotobiotic mouse models and clinical data that linked microbiota-induced pattern recognition receptor signalling with atherogenesis. Based on recent insights, we here provide an overview of how the gut microbiota could affect endothelial cell function and platelet activation, to promote arterial thrombosis. LINKED ARTICLES: This article is part of a themed section on When Pharmacology Meets the Microbiome: New Targets for Therapeutics? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.24/issuetoc.

The role of adjuvant probiotics to attenuate intestinal inflammatory responses due to cancer treatments

Chemotherapy and radiotherapy treatment regimens for gastrointestinal, peritoneal and pelvic tumours can disrupt the intestinal microbiome and intestinal epithelia. Such disturbances can provoke symptoms such as diarrhoea, nausea and vomiting. Chemotherapy and radiotherapy induced gastrointestinal toxicity aggravating intestinal microbiome dysbiosis is postulated to adversely alter the intestinal microbiome, with a consequent induced pro-inflammatory effect that disrupts the intestinal microbiome-epithelia-mucosal immunity axis. Although not widely recognised, the intestinal mucosa is the largest and most densely and dynamically populated immune-environment. Cancer treatment adverse effects that affect intestinal and mucosal cells inadvertently target and disrupt resident intestinal macrophages, the cells that marshal immune activity in the intestinal mucosa by shaping pro-inflammatory and anti-inflammatory activities to control and eradicate infectious insults and maintain local homeostasis. Pathobionts (bacteria capable of pathogenic pro-inflammatory activity) and noxious environmental and bacterial antigens use the intestinal epithelia and gap junctions as a point of entry into the systemic circulation. This translocation movement promotes toxic sequelae that obstruct intestinal macrophage functions resulting in uncontrolled local and systemic pro-inflammatory activity, loss of phagocytic function and loss of expression of tight junction proteins. Probiotic bacteria as an adjunctive treatment shows efficacy in ameliorating enteropathies such as mucositis/diarrhoea resulting from chemotherapy or radiotherapy regimens. As such we posit that an important benefit that warrants a further focused research effort is the administration of adjuvant probiotics to help reduce the incidence of febrile neutropenia.

Gut⁻Liver Axis: How Do Gut Bacteria Influence the Liver?

Chronic liver diseases are a major cause of morbidity and mortality worldwide. Recently, gut dysbiosis was identified as an important factor in the pathogenesis of liver diseases. The relationship between gut microbiota and the liver is still not well understood; however, dysfunction of the gut mucosal barrier ("leaky gut") and increased bacterial translocation into the liver via the gut⁻liver axis probably play crucial roles in liver disease development and progression. The liver is an important immunological organ, and, after exposure to gut-derived bacteria via portal circulation, it responds with activation of the innate and adaptive immune system, leading to hepatic injury. A better understanding of the pathophysiological links among gut dysbiosis, the integrity of the gut barrier, and the hepatic immune response to gut-derived factors is essential for the development of new therapies to treat chronic liver diseases.

Fecal microbiota transplantation: a promising strategy in preventing the progression of non-alcoholic steatohepatitis and improving the anti-cancer immune response

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) has the potential to progress to hepatocellular carcinoma (HCC). However, limited therapies are currently available for the treatment of advanced HCC, and one must strive to search for novel strategies.

AREAS COVERED

We provide insight on current knowledge related to gut microbiota and NAFLD, summarize the sequence linking obesity to HCC and highlight gut dysbiosis in obesity and its consequences on the liver. We detail the impact of the gut microbiota on immune checkpoint inhibitors, and speculate on the role of fecal microbiota transplantation (FMT) in NAFLD and in improving anti-neoplastic immune response.

EXPERT OPINION

Manipulation of the gut microbiota seems promising in the secondary prevention of NAFLD/NASH and/or in potentiating anti-cancer immune response, notably by a global 'resetting' using FMT. However, the composition of a 'harmful' gut microbiome in HCC still needs to be characterized, and the impact of FMT on HCC growth needs to be assessed.

The immunomodulatory role of probiotics in allergy therapy

The increased incidence of allergic disorders may be the result of a relative fall in microbial induction in the intestinal immune system during infancy and early childhood. Probiotics have recently been proposed as viable microorganisms for the prevention and treatment of specific allergic diseases. Different mechanisms have been considered for this probiotic property, such as generation of cytokines from activated pro-T-helper type 1 after bacterial contact. However, the effects of its immunomodulatory potential require validation for clinical applications. This review will focus on the currently available data on the benefits of probiotics in allergy disease.

Probiotics and Their Potential Preventive and Therapeutic Role for Cancer, High Serum Cholesterol, and Allergic and HIV Diseases

The potential health benefits of probiotics have long been elucidated since Metchnikoff and his coworkers postulated the association of probiotic consumption on human's health and longevity. Since then, many scientific findings and research have further established the correlation of probiotic and gut-associated diseases such as irritable bowel disease and chronic and antibiotic-associated diarrhea. However, the beneficial impact of probiotic is not limited to the gut-associated diseases alone, but also in different acute and chronic infectious diseases. This is due to the fact that probiotics are able to modify the intestinal microbial ecosystem, enhance the gut barrier function, provide competitive adherence to the mucosa and epithelium, produce antimicrobial substances, and modulate the immune activity by enhancing the innate and adaptive immune response. Nevertheless, the current literature with respect to the association of probiotic and cancer, high serum cholesterol, and allergic and HIV diseases are still scarce and controversial. Therefore, in the present work, we reviewed the potential preventive and therapeutic role of probiotics for cancer, high serum cholesterol, and allergic and HIV diseases as well as providing its possible mechanism of actions.

Anticancer drug discovery from Chinese medicinal herbs

Cancer is still presenting a serious threat to human health worldwide. The understanding of the complex biology of cancer and the development of oncotherapy have led to increasing treatment approaches such as targeted therapy and immunotherapy. Chinese medicinal herbs have attracted considerable attention due to their potential anticancer effects. Some natural products or formulae from Chinese medicinal herbs with directly or indirectly anticancer effects have been reported. In this article, we summarized the current progression on development of anticancer drugs from Chinese medicinal herbs, toward providing ideas for further development and application of Chinese medicinal herbs in cancer therapy.

The gut-liver axis and the intersection with the microbiome

In the past decade, an exciting realization has been that diverse liver diseases - ranging from nonalcoholic steatohepatitis, alcoholic steatohepatitis and cirrhosis to hepatocellular carcinoma - fall along a spectrum. Work on the biology of the gut-liver axis has assisted in understanding the basic biology of both alcoholic fatty liver disease and nonalcoholic fatty liver disease (NAFLD). Of immense importance is the advancement in understanding the role of the microbiome, driven by high-throughput DNA sequencing and improved computational techniques that enable the complexity of the microbiome to be interrogated, together with improved experimental designs. Here, we review gut-liver communications in liver disease, exploring the molecular, genetic and microbiome relationships and discussing prospects for exploiting the microbiome to determine liver disease stage and to predict the effects of pharmaceutical, dietary and other interventions at a population and individual level. Although much work remains to be done in understanding the relationship between the microbiome and liver disease, rapid progress towards clinical applications is being made, especially in study designs that complement human intervention studies with mechanistic work in mice that have been humanized in multiple respects, including the genetic, immunological and microbiome characteristics of individual patients. These 'avatar mice' could be especially useful for guiding new microbiome-based or microbiome-informed therapies.

The hepatoprotective effect of the probiotic Clostridium butyricum against carbon tetrachloride-induced acute liver damage in mice

Previous studies have revealed that the probiotic Clostridium butyricum (C. butyricum) can attenuate cirrhosis in chronic non-alcoholic liver disease. However, the effects of C. butyricum on acute liver injury (ALI) remain unclear. Therefore, the present study aims to examine the hepatoprotective effects and the underlying mechanisms employed by C. butyricum in a carbon tetrachloride (CCl₄)-induced ALI murine model. Here, we evaluated the survival rate and the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), anti-oxidants, cytokines and the gut microbiota to elucidate the potential mechanisms by which C. butyricum is hepatoprotective. Our results show that five days of prophylactic C. butyricum treatment significantly reduced mortality by 40% and decreased the CCl₄-induced levels of ALT and AST in the serum of these mice. Additionally, prophylactic treatment with C. butyricum increased the activity of both superoxide dismutase (SOD) and catalase (CAT), and substantially reduced malondialdehyde (MDA) levels, which were deteriorated in the untreated ALI mice compared to normal control mice. Furthermore, C. butyricum up-regulated the nuclear factor (erythroid-derived 2)-like 2 (NRF2) content. CCl₄-induced mice also exhibited considerable increases of phosphorylation of nuclear factor-kappa B (NF-κB) p65 and pro-inflammatory cytokines, including interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). However, the inflammatory responses of the liver induced by CCl₄ were significantly alleviated by C. butyricum pretreatment. Additionally, we found that interleukin-10 (IL-10), an anti-inflammatory mediator, was increased in the C. butyricum-pretreated group. Microbiota analysis in these mice revealed crosstalk between the gut microbial metabolites and ALI. The intestinal flora was changed by CCl₄ administration and was shifted by the probiotic C. butyricum toward more beneficial bacteria, particularly the Clostridia orders, which are the known producers of the anti-inflammatory and anti-oxidative metabolite butyrate. In conclusion, we found that the intestinal flora changes after the intraperitoneal injection of CCl₄. We also offer novel insights into the mechanism by which probiotic C. butyricum pretreatment alleviates the CCl₄-induced inflammation and oxidative stress of the liver via the modulation of NRF2, NF-κB p65, IL-10 and the intestinal microbiota in mice.

Probiotic Lactobacillus Paracasei Expressing a Nucleic Acid-Hydrolyzing Minibody (3D8 Scfv) Enhances Probiotic Activities in Mice Intestine as Revealed by Metagenomic Analyses

Probiotics are well known for their beneficial effects for animals, including humans and livestock. Here, we tested the probiotic activity of Lactobacillus paracasei expressing 3D8 scFv, a nucleic acid-hydrolyzing mini-antibody, in mice intestine. A total of 18 fecal samples derived from three different conditions at two different time points were subjected to high-throughput 16S ribosomal RNA (rRNA) metagenomic analyses. Bioinformatic analyses identified an average of 290 operational taxonomic units. After administration of L. paracasei, populations of the probiotics L. paracasei, Lactobacillus reuteri, and Pediococcus acidilactici increased, whereas the population of harmful bacteria such as Helicobacter species decreased. Furthermore, continuous administration of L. paracasei resulted in L. paracasei emerging as the dominant probiotic after competition with other existing probiotics. Expression of 3D8 scFv protein specifically increased the population of P. acidilactici, which is another probiotic. In summary, our results showed that L. paracasei expressing 3D8 scFv protein enhanced probiotic activity in mice intestine with no observable side effects. Thus, the system developed in this study may be a good tool for the expression of recombinant protein using probiotics.

Faire face à la menace infectieuse en réanimation : de la veille épidémiologique à l’innovation. Actes du séminaire de recherche translationnelle de la Société de réanimation de langue française (5 décembre 2017)

Le séminaire annuel de la Commission de recherche translationnelle de la SRLF a pour but de réunir des cliniciens et scientifiques autour de grandes thématiques de recherche en médecine intensive et réanimation. La quatrième édition du séminaire a porté sur l’infectiologie, thématique au centre des préoccupations des réanimateurs. Les interventions se sont ainsi focalisées sur des aspects aussi divers que les relations hôtes–pathogènes, la contribution de pathogènes dans des pathologies habituellement considérées comme non infectieuses, l’émergence de nouveaux risques infectieux, les avancées technologiques du diagnostic moléculaire des infections et le développement de stratégies antibactériennes alternatives à l’antibiothérapie classique.

The microbiome in cancer immunotherapy: Diagnostic tools and therapeutic strategies

The fine line between human health and disease can be driven by the interplay between host and microbial factors. This "metagenome" regulates cancer initiation, progression, and response to therapies. Besides the capacity of distinct microbial species to modulate the pharmacodynamics of chemotherapeutic drugs, symbiosis between epithelial barriers and their microbial ecosystems has a major impact on the local and distant immune system, markedly influencing clinical outcome in cancer patients. Efficacy of cancer immunotherapy with immune checkpoint antibodies can be diminished with administration of antibiotics, and superior efficacy is observed with the presence of specific gut microbes. Future strategies of precision medicine will likely rely on novel diagnostic and therapeutic tools with which to identify and correct defects in the microbiome that compromise therapeutic efficacy.

Comprehensive comparison of polysaccharides from Ganoderma lucidum and G. sinense: chemical, antitumor, immunomodulating and gut-microbiota modulatory properties

Both Ganoderma lucidum (GL) and G. sinense (GS) are used as Lingzhi in China. Their functions are assumed to mainly derive from triterpenes and polysaccharides; however, the two species have very different triterpenes profiles, if this was the case, then the bioactivity of these two species should differ. Instead, could the polysaccharides be similar, contributing to the shared therapeutic basis? In this study, two main polysaccharide fractions from different batches of GL and GS were systematically compared by a series of chemical and biological experiments. The results showed that the polysaccharides from two species shared the same structural features in terms of mono-/oligo-saccharide profiles, molecular size, sugar linkages, and IR/NMR spectra. In addition, these polysaccharides showed similar tumor-suppressive activity in mice. Further study on RAW264.7 cells indicated that these polysaccharides exhibited similar inducing effects to macrophages, as evaluated in the phagocytosis function, NO/cytokines production, inhibition against the viability and migration of cancer cells. Mechanistic investigation revealed the identical activation via TLR-4 related MAPK/NF-κB signaling pathway and gut-microbiota modulatory effects. In summary, GL and GS polysaccharides presented similar chemical features, antitumor/immunomodulating activities and mechanism; this establishes polysaccharides as the active principles and supports the official use of both species as Lingzhi.

Ecological Therapeutic Opportunities for Oral Diseases

The three main oral diseases of humans, that is, caries, periodontal diseases, and oral candidiasis, are associated with microbiome shifts initiated by changes in the oral environment and/or decreased effectiveness of mucosal immune surveillance. In this review, we discuss the role that microbial-based therapies may have in the control of these conditions. Most investigations on the use of microorganisms for management of oral disease have been conducted with probiotic strains with some positive but very discrete clinical outcomes. Other strategies such as whole oral microbiome transplantation or modification of community function by enrichment with health-promoting indigenous oral strains may offer more promise, but research in this field is still in its infancy. Any microbial-based therapeutics for oral conditions, however, are likely to be only one component within a holistic preventive strategy that should also aim at modification of the environmental influences responsible for the initiation and perpetuation of microbiome shifts associated with oral dysbiosis.

Roseburia intestinalis inhibits interleukin‑17 excretion and promotes regulatory T cells differentiation in colitis

Roseburia intestinalis (R. intestinalis) is one of the dominant intestinal bacterial microbiota and is decreased in patients with inflammatory bowel disease (IBD). It helps protect colonic mucosa against the development of inflammation and subsequent IBD, however its underlying mechanisms are unclear. The aim of the present study was to evaluate the anti-inflammatory properties of R. intestinalis in vitro and in an animal model of IBD. The effects of R. intestinalis on disease activity index (DAI) scores, intestinal pathology, the expression of interleukin (IL)-17 and the frequency of CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Treg) were evaluated in vivo in a model of 2,4,6-trinitrobenzenesulfonic acid solution (TNBS)-induced colitis. Compared with the control group, TNBS-treated mice had significantly higher secretion of IL-17, higher DAI scores, a lower ratio of Treg, reduced colon lengths and higher histological scores for colon inflammation. The administration of R. intestinalis significantly downregulated the expression of IL-17, increased the ratio of Treg and ameliorated the high DAI scores and the pathological signs of inflammation in the colon compared with mice treated with TNBS alone. Gene expression profiling was also used to detect the expression of IL-17 in human IBD and healthy control specimens. To extend these findings to an in vitro model of inflammation the human colon epithelial cell line NCM460 was stimulated with lipopolysaccharide (LPS) to induce inflammation and co-cultured with R. intestinalis and changes in IL-17 expression were evaluated. R. intestinalis inhibited the LPS-induced secretion of IL-17 by NCM460 cells. In conclusion, these results demonstrate that R. intestinalis inhibits IL-17 secretion and promotes Treg differentiation in colitis, suggesting that R. intestinalis could be of potential use in the treatment of IBD.

The choroid plexus epithelium as a novel player in the stomach-brain axis during Helicobacter infection

Several studies suggest a link between shifts in gut microbiota and neurological disorders. Recently, we reported a high prevalence of Helicobacter suis (H. suis) in patients with Parkinson's disease. Here, we evaluated the effect of gastric H. suis infection on the brain in mice. One month of infection with H. suis resulted in increased brain inflammation, reflected in activation of microglia and cognitive decline. Additionally, we detected choroid plexus inflammation and disruption of the epithelial blood-cerebrospinal fluid (CSF) barrier upon H. suis infection, while the endothelial blood-brain barrier (BBB) remained functional. These changes were accompanied by leakage of the gastrointestinal barrier and low-grade systemic inflammation, suggesting that H. suis-evoked gastrointestinal permeability and subsequent peripheral inflammation induces changes in brain homeostasis via changes in blood-CSF barrier integrity. In conclusion, this study shows for the first time that H. suis infection induces inflammation in the brain associated with cognitive decline and that the choroid plexus is a novel player in the stomach-brain axis.

Mycotoxin: Its Impact on Gut Health and Microbiota

The secondary metabolites produced by fungi known as mycotoxins, are capable of causing mycotoxicosis (diseases and death) in human and animals. Contamination of feedstuffs as well as food commodities by fungi occurs frequently in a natural manner and is accompanied by the presence of mycotoxins. The occurrence of mycotoxins' contamination is further stimulated by the on-going global warming as reflected in some findings. This review comprehensively discussed the role of mycotoxins (trichothecenes, zearalenone, fumonisins, ochratoxins, and aflatoxins) toward gut health and gut microbiota. Certainly, mycotoxins cause perturbation in the gut, particularly in the intestinal epithelial. Recent insights have generated an entirely new perspective where there is a bi-directional relationship exists between mycotoxins and gut microbiota, thus suggesting that our gut microbiota might be involved in the development of mycotoxicosis. The bacteria-xenobiotic interplay for the host is highlighted in this review article. It is now well established that a healthy gut microbiota is largely responsible for the overall health of the host. Findings revealed that the gut microbiota is capable of eliminating mycotoxin from the host naturally, provided that the host is healthy with a balance gut microbiota. Moreover, mycotoxins have been demonstrated for modulation of gut microbiota composition, and such alteration in gut microbiota can be observed up to species level in some of the studies. Most, if not all, of the reported effects of mycotoxins, are negative in terms of intestinal health, where beneficial bacteria are eliminated accompanied by an increase of the gut pathogen. The interactions between gut microbiota and mycotoxins have a significant role in the development of mycotoxicosis, particularly hepatocellular carcinoma. Such knowledge potentially drives the development of novel and innovative strategies for the prevention and therapy of mycotoxin contamination and mycotoxicosis.

Human Gut Microbiota and Gastrointestinal Cancer

Human gut microbiota play an essential role in both healthy and diseased states of humans. In the past decade, the interactions between microorganisms and tumors have attracted much attention in the efforts to understand various features of the complex microbial communities, as well as the possible mechanisms through which the microbiota are involved in cancer prevention, carcinogenesis, and anti-cancer therapy. A large number of studies have indicated that microbial dysbiosis contributes to cancer susceptibility via multiple pathways. Further studies have suggested that the microbiota and their associated metabolites are not only closely related to carcinogenesis by inducing inflammation and immune dysregulation, which lead to genetic instability, but also interfere with the pharmacodynamics of anticancer agents. In this article, we mainly reviewed the influence of gut microbiota on cancers in the gastrointestinal (GI) tract (including esophageal, gastric, colorectal, liver, and pancreatic cancers) and the regulation of microbiota by diet, prebiotics, probiotics, synbiotics, antibiotics, or the Traditional Chinese Medicine. We also proposed some new strategies in the prevention and treatment of GI cancers that could be explored in the future. We hope that this review could provide a comprehensive overview of the studies on the interactions between the gut microbiota and GI cancers, which are likely to yield translational opportunities to reduce cancer morbidity and mortality by improving prevention, diagnosis, and treatment.

Targeting gut microbiota in hepatocellular carcinoma: probiotics as a novel therapy

Hepatocellular carcinoma (HCC), the most common primary liver cancer, is one of the dreaded complications of chronic liver disease. Recent experimental and clinical studies have revealed that the alteration of gut-liver axis plays a pivotal role in the onset of chronic liver diseases, including HCC. Altered gut microbiota and endotoxemia are increasingly recognized as critical components in promoting the progression of chronic liver diseases to HCC. Probiotics have been suggested as a novel, safe and cost-effective approach to prevent or treat HCC. Mechanisms by which probiotics exerts their anti-cancer effects include their ability to bind carcinogens, modulation of gut microbiota, improvement of intestinal barrier function, and immunomodulation. This review summarizes the literature findings of the changes in gut microbiota linked to HCC, and discusses the possible therapeutic implications of probiotics for HCC.

Alterations of the Gut Microbiota in Hashimoto's Thyroiditis Patients

BACKGROUND

Hashimoto's thyroiditis (HT) is an organ-specific autoimmune disease in which both genetic predisposition and environmental factors serve as disease triggers. Many studies have indicated that alterations in the gut microbiota are important environmental factors in the development of inflammatory and autoimmune diseases. A comparative analysis was systematically performed of the gut microbiota in HT patients and healthy controls.

METHODS

First, a cross-sectional study of 28 HT patients and 16 matched healthy controls was conducted. Fecal samples were collected, and microbiota were analyzed using 16S ribosomal RNA gene sequencing. Second, an independent cohort of 22 HT patients and 11 healthy controls was used to evaluate the diagnostic potential of the selected biomarkers.

RESULTS

Similar levels of bacterial richness and diversity were found in the gut microbiota of HT patients and healthy controls (p = 0.11). A detailed fecal microbiota Mann-Whitney U-test (Q value <0.05) revealed that the abundance levels of Blautia, Roseburia, Ruminococcus_torques_group, Romboutsia, Dorea, Fusicatenibacter, and Eubacterium_hallii_group genera were increased in HT patients, whereas the abundance levels of Fecalibacterium, Bacteroides, Prevotella_9, and Lachnoclostridium genera were decreased. A correlation matrix based on the Spearman correlation distance confirmed correlations among seven clinical parameters. Additionally, the linear discriminant analysis effect size method showed significant differences in 27 genera between the two groups that were strongly correlated with clinical parameters. The linear discriminant analysis value was used to select the first 10 species from the 27 different genera as biomarkers, achieving area under the curve values of 0.91 and 0.88 for exploration and validation data, respectively.

CONCLUSIONS

Characterization of the gut microbiota in HT patients confirmed that HT patients have altered gut microbiota and that gut microbiota are correlated with clinical parameters, suggesting that microbiome composition data could be used for disease diagnosis. Further investigation is required to understand better the role of the gut microbiota in the pathogenesis of HT.

Gut roundtable meeting paper: selected recent advances in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) ranks number three among the most frequent causes of death from solid tumors worldwide. With obesity and fatty liver diseases as risk factors on the rise, HCC represents an ever increasing challenge. While there is still no curative treatment for most patients numerous novel drugs have been proposed, but most ultimately failed in phase III trials. This manuscript targets therapeutic advances and most burning issues. Expert key point summaries and urgent research agenda are provided regarding risk factors, including microbiota, need for prognostic and predictive biomarkers and the equivocal role of liver biopsy. Therapeutic topics highlighted are locoregional techniques, combination therapies and the potential of immunotherapy. Finally the manuscript provides a critical evaluation of novel targets and strategies for personalized treatment of HCC.

Intestinal Lactobacillus in health and disease, a driver or just along for the ride?

Metagenomics and related methods have led to significant advances in our understanding of the human microbiome. Members of the genus Lactobacillus, although best understood for essential roles in food fermentations and applications as probiotics, have also come to the fore in a number of untargeted gut microbiome studies in humans and animals. Even though Lactobacillus is only a minor member of the human colonic microbiota, the proportions of those bacteria are frequently either positively or negatively correlated with human disease and chronic conditions. Recent findings on Lactobacillus species in human and animal microbiome research, together with the increased knowledge on probiotic and other ingested lactobacilli, have resulted in new perspectives on the importance of this genus to human health.

Human Gut Microbiota and Gastrointestinal Cancer

Human gut microbiota play an essential role in both healthy and diseased states of humans. In the past decade, the interactions between microorganisms and tumors have attracted much attention in the efforts to understand various features of the complex microbial communities, as well as the possible mechanisms through which the microbiota are involved in cancer prevention, carcinogenesis, and anti-cancer therapy. A large number of studies have indicated that microbial dysbiosis contributes to cancer susceptibility via multiple pathways. Further studies have suggested that the microbiota and their associated metabolites are not only closely related to carcinogenesis by inducing inflammation and immune dysregulation, which lead to genetic instability, but also interfere with the pharmacodynamics of anticancer agents. In this article, we mainly reviewed the influence of gut microbiota on cancers in the gastrointestinal (GI) tract (including esophageal, gastric, colorectal, liver, and pancreatic cancers) and the regulation of microbiota by diet, prebiotics, probiotics, synbiotics, antibiotics, or the Traditional Chinese Medicine. We also proposed some new strategies in the prevention and treatment of GI cancers that could be explored in the future. We hope that this review could provide a comprehensive overview of the studies on the interactions between the gut microbiota and GI cancers, which are likely to yield translational opportunities to reduce cancer morbidity and mortality by improving prevention, diagnosis, and treatment.

Intestinal Microbiome Shifts, Dysbiosis, Inflammation, and Non-alcoholic Fatty Liver Disease

Adverse fluctuations in the distribution of the intestinal microbiome cohort has been associated with the onset of intra- and extra-intestinal inflammatory conditions, like the metabolic syndrome (MetS) and it's hepatic manifestation, non-alcoholic fatty liver disease (NAFLD). The intestinal microbial community of obese compared to lean subjects has been shown to undergo configurational shifts in various genera, including but not limited to increased abundances of Prevotella, Escherichia, Peptoniphilus, and Parabacteroides and decreased levels of Bifidobacteria, Roseburia, and Eubacteria genera. At the phylum level, decreased Bacteroidetes and increased Firmicutes have been reported. The intestinal microbiota therefore presents an important target for designing novel therapeutic modalities that target extra-intestinal inflammatory disorders, such as NAFLD. This review hypothesizes that disruption of the intestinal-mucosal macrophage interface is a key factor in intestinal-liver axis disturbances. Intestinal immune responses implicated in the manifestation, maintenance and progression of NAFLD provide insights into the dialogue between the intestinal microbiome, the epithelia and mucosal immunity. The pro-inflammatory activity and immune imbalances implicated in NAFLD pathophysiology are reported to stem from dysbiosis of the intestinal epithelia which can serve as a source of hepatoxic effects. We posit that the hepatotoxic consequences of intestinal dysbiosis are compounded through intestinal microbiota-mediated inflammation of the local mucosa that encourages mucosal immune dysfunction, thus contributing important plausible insight in NAFLD pathogenesis. The administration of probiotics and prebiotics as a cure-all remedy for all chronic diseases is not advocated, instead, the incorporation of evidence based probiotic/prebiotic formulations as adjunctive modalities may enhance lifestyle modification management strategies for the amelioration of NAFLD.

The influence of prebiotic or probiotic supplementation on antibody titers after influenza vaccination: a systematic review and meta-analysis of randomized controlled trials

Background

Influenza infection is a common disease with a huge disease burden. Influenza vaccination has been widely used, but concerns regarding vaccine efficacy exist, especially in the elderly. Probiotics are live microorganisms with immunomodulatory effects and may enhance the immune responses to influenza vaccination.

Methods

We conducted a systematic review and meta-analysis to determine the influence of prebiotics/probiotics/synbiotics supplementation on vaccine responses to influenza vaccination. Studies were systematically identified from electronic databases up to July 2017. Information regarding study population, influenza vaccination, components of supplements, and immune responses were extracted and analyzed. Twelve studies, investigating a total of 688 participants, were included in this review.

Results

Patients with prebiotics/probiotics supplements were found to have higher influenza hemagglutination inhibition antibody titers after vaccination (for A/H1N1, 42.89 vs 35.76, mean difference =7.14, 95% CI =2.73, 11.55, P=0.002; for A/H3N2, 105.4 vs 88.25, mean difference =17.19, 95% CI =3.39, 30.99, P=0.01; for B strain, 34.87 vs 30.73, mean difference =4.17, 95% CI =0.37, 7.96, P=0.03).

Conclusion

Supplementation with prebiotics or probiotics may enhance the influenza hemagglutination inhibition antibody titers in all A/H1N1, A/H3N2, and B strains (20%, 19.5%, and 13.6% increases, respectively). Concomitant prebiotics or probiotics supplementation with influenza vaccination may hold great promise for improving vaccine efficacy. However, high heterogeneity was observed and further studies are warranted.

Bile acid metabolism regulated by the gut microbiota promotes non-alcoholic steatohepatitis-associated hepatocellular carcinoma in mice

Gut microbiota plays a significant role in the development of hepatocellular carcinoma (HCC) in non-alcoholic steatohepatitis (NASH). However, understanding of the precise mechanism of this process remains incomplete. A new class steatohepatitis-inducing high-fat diet (HFD), namely STHD-01, can promote the development of HCC without the administration of chemical carcinogens. Using this diet, we comprehensively analyzed changes in the gut microbiota and its metabolic functions during the development of HCC in NASH. Mice fed the STHD-01 developed NASH within 9 weeks. NASH further progressed into HCC by 41 weeks. Treatment with antibiotics significantly attenuated liver pathology and suppressed tumor development, indicating the critical role of the gut microbiota in tumor development in this model. Accumulation of cholesterol and bile acids in the liver and feces increased after feeding the mice with STHD-01. Treatment with antibiotics did not reverse these phenotypes. In contrast, accumulation of secondary bile acids was dramatically reduced after the treatment with antibiotics, suggesting the critical role of the gut microbiota in the conversion of primary bile acids to secondary bile acids. Secondary bile acids such as deoxycholic acid activated the mTOR, pathway in hepatocytes. Activation of mTOR was observed in the liver of mice fed STHD-01, and the activation was reduced when mice were treated with antibiotics. Collectively, bile acid metabolism by the gut microbiota promotes HCC development in STHD-01-induced NASH.

Probiotics and their role in gastrointestinal cancers prevention and treatment; an overview

Cancers of the gastrointestinal (GI) track are a serious global health problem. The human GI tract is home to trillions of microorganisms that known as gut microbiota and have established a symbiotic relationship with the host. The human intestinal microbiota plays an important role in the development of the gut immune system, metabolism, nutrition absorption, production of short-chain fatty acids and essential vitamins, resistance to pathogenic microorganisms, and modulates a normal immunological response. Microbiota imbalance has been involved in many disorders including inflammatory bowel disease, obesity, asthma, psychiatric illnesses, and cancers. Oral administration of probiotics seems to play a protective role against cancer development as a kind of functional foods. Moreover, clinical application of probiotics has shown that some probiotic strains can reduce the incidence of post-operative inflammation in cancer patients. In the present narrative review, we carried out update knowledge on probiotic effects and underlying mechanism to GI cancers. Currently, it is accept that most commercial probiotic products are generally safe and can used as a supplement for cancer prevention and treatment. Nevertheless, well-designed, randomized, double blind, placebo-controlled human studies are required to gain the acceptance of the potential probiotics as an alternative therapy for cancer control..

Microbiome at the Frontier of Personalized Medicine

The genomic revolution promises to transform our approach to treat patients by individualizing treatments, reducing adverse events, and decreasing health care costs. The early advances using this have been realized primarily by optimizing preventive and therapeutic approaches in cancer using human genome sequencing. The ability to characterize the microbiome, which includes all the microbes that reside within and upon us and all their genetic elements, using next-generation sequencing allows us to now incorporate this important contributor to human disease into developing new preventive and therapeutic strategies. In this review we highlight the importance of the microbiome in all aspects of human disease, including pathogenesis, phenotype, prognosis, and response to treatment, as well as their role as diagnostic and therapeutic biomarkers. We provide a role for next-generation sequencing in both precise microbial identification of infectious diseases and characterization of microbial communities and their function. Taken together, the microbiome is emerging as an integral part of precision medicine approach as it not only contributes to interindividual variability in all aspects of a disease but also represents a potentially modifiable factor that is amenable to targeting by therapeutics.

Blockade of CB1 cannabinoid receptor alters gut microbiota and attenuates inflammation and diet-induced obesity

Obesity is characterized by chronic low-grade, systemic inflammation, altered gut microbiota, and gut barrier disruption. Additionally, obesity is associated with increased activity of endocannabinoid system (eCB). However, the clear connection between gut microbiota and the eCB system in the regulation of energy homeostasis and adipose tissue inflammation and metabolism, remains to be established. We investigated the effect of treatment of mice with a cannabinoid receptor 1 (CB1) antagonist on Diet-Induced Obesity (DIO), specifically whether such a treatment that blocks endocannabinoid activity can induce changes in gut microbiota and anti-inflammatory state in adipose tissue. Blockade of CB1 attenuated DIO, inflammatory cytokines and trafficking of M1 macrophages into adipose tissue. Decreased inflammatory tone was associated with a lower intestinal permeability and decreased metabolic endotoxemia as evidenced by reduced plasma LPS level, and improved hyperglycemia and insulin resistance. 16S rRNA metagenomics sequencing revealed that CB1 blockade dramatically increased relative abundance of Akkermansia muciniphila and decreased Lanchnospiraceae and Erysipelotrichaceae in the gut. Together, the current study suggests that blocking of CB1 ameliorates Diet-Induced Obesity and metabolic disorder by modulating macrophage inflammatory mediators, and that this effect is associated with alterations in gut microbiota and their metabolites.