Gut Microbiome-Mediated Alteration of Immunity, Inflammation, and Metabolism Involved in the Regulation of Non-alcoholic Fatty Liver Disease

Gut microbial metabolites in MASLD: Implications of mitochondrial dysfunction in the pathogenesis and treatment

With an increasing prevalence, metabolic dysfunction-associated steatotic liver disease (MASLD) has become a major global health problem. MASLD is well-known as a multifactorial disease. Mitochondrial dysfunction and alterations in the gut bacteria are 2 vital events in MASLD. Recent studies have highlighted the cross-talk between microbiota and mitochondria, and mitochondria are recognized as pivotal targets of the gut microbiota to modulate the host's physiological state. Mitochondrial dysfunction plays a vital role in MASLD and is associated with multiple pathological changes, including hepatocyte steatosis, oxidative stress, inflammation, and fibrosis. Metabolites are crucial mediators of the gut microbiota that influence extraintestinal organs. Additionally, regulation of the composition of gut bacteria may serve as a promising therapeutic strategy for MASLD. This study reviewed the potential roles of several common metabolites in MASLD, emphasizing their impact on mitochondrial function. Finally, we discuss the current treatments for MASLD, including probiotics, prebiotics, antibiotics, and fecal microbiota transplantation. These methods concentrate on restoring the gut microbiota to promote host health.

Mendelian randomization suggests a causal relationship between gut microbiota and nonalcoholic fatty liver disease in humans

Targeting the gut microbiota is an emerging strategy to treat nonalcoholic fatty liver disease (NAFLD). Nonetheless, the causal relationship between specific gut microbiota and NAFLD remains unclear. We first obtained genome-wide association study statistics on gut microbiota and NAFLD from publicly available databases. We then performed the Mendelian randomization (MR) analysis to determine the potential causal relationship between the gut microbiota and NAFLD by 5 different methods, and conducted a series of sensitivity analyses to validate the robustness of the MR analysis results. Furthermore, we investigated the direction of causality by bidirectional MR analysis. For 211 gut microbiota, 2 MR methods confirmed that phylum Tenericutes, class Deltaproteobacteria and class Mollicutes were significantly associated with the risk of NAFLD. Heterogeneity (P > .05) and pleiotropy (P > .05) analyses validated the robustness of the MR results. There was no causal effect of NAFLD on these bacterial taxa in the reverse MR analysis. We identified specific gut microbiota with causal effects on NAFLD through gene prediction, which may provide useful guidance for targeting the gut microbiota to intervene and treat NAFLD.

Changes in Bacterial Gut Composition in Parkinson's Disease and Their Metabolic Contribution to Disease Development: A Gut Community Reconstruction Approach

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disease with the major symptoms comprising loss of movement coordination (motor dysfunction) and non-motor dysfunction, including gastrointestinal symptoms. Alterations in the gut microbiota composition have been reported in PD patients vs. controls. However, it is still unclear how these compositional changes contribute to disease etiology and progression. Furthermore, most of the available studies have focused on European, Asian, and North American cohorts, but the microbiomes of PD patients in Latin America have not been characterized. To address this problem, we obtained fecal samples from Colombian participants (n = 25 controls, n = 25 PD idiopathic cases) to characterize the taxonomical community changes during disease via 16S rRNA gene sequencing. An analysis of differential composition, diversity, and personalized computational modeling was carried out, given the fecal bacterial composition and diet of each participant. We found three metabolites that differed in dietary habits between PD patients and controls: carbohydrates, trans fatty acids, and potassium. We identified six genera that changed significantly in their relative abundance between PD patients and controls, belonging to the families Lachnospiraceae, Lactobacillaceae, Verrucomicrobioaceae, Peptostreptococcaceae, and Streptococcaceae. Furthermore, personalized metabolic modeling of the gut microbiome revealed changes in the predicted production of seven metabolites (Indole, tryptophan, fructose, phenylacetic acid, myristic acid, 3-Methyl-2-oxovaleric acid, and N-Acetylneuraminic acid). These metabolites are associated with the metabolism of aromatic amino acids and their consumption in the diet. Therefore, this research suggests that each individual's diet and intestinal composition could affect host metabolism. Furthermore, these findings open the door to the study of microbiome-host interactions and allow us to contribute to personalized medicine.

The bidirectional immune crosstalk in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an unabated risk factor for end-stage liver diseases with no available therapies. Dysregulated immune responses are critical culprits of MASLD pathogenesis. Independent contributions from either the innate or adaptive arms of the immune system or their unidirectional interplay are commonly studied in MASLD. However, the bidirectional communication between innate and adaptive immune systems and its impact on MASLD remain insufficiently understood. Given that both innate and adaptive immune cells are indispensable for the development and progression of inflammation in MASLD, elucidating pathogenic contributions stemming from the bidirectional interplay between these two arms holds potential for development of novel therapeutics for MASLD. Here, we review the immune cell types and bidirectional pathways that influence the pathogenesis of MASLD and highlight potential pharmacologic approaches to combat MASLD based on current knowledge of this bidirectional crosstalk.

The microbiome and the gut-lung axis in tuberculosis: interplay in the course of disease and treatment

Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis (MTB) that remains a significant global health challenge. The extensive use of antibiotics in tuberculosis treatment, disrupts the delicate balance of the microbiota in various organs, including the gastrointestinal and respiratory systems. This gut-lung axis involves dynamic interactions among immune cells, microbiota, and signaling molecules from both organs. The alterations of the microbiome resulting from anti-TB treatment can significantly influence the course of tuberculosis, impacting aspects such as complete healing, reinfection, and relapse. This review aims to provide a comprehensive understanding of the gut-lung axis in the context of tuberculosis, with a specific focus on the impact of anti-TB treatment on the microbiome.

Role of innate immunity and systemic inflammation in cystic fibrosis disease progression

Pathophysiological manifestations of cystic fibrosis (CF) result from a functional defect in the cystic fibrosis transmembrane conductance regulator (CFTR) paving way for mucus obstruction and pathogen colonization. The role of CFTR in modulating immune cell function and vascular integrity, irrespective of mucus thickening, in determining the host cell response to pathogens/allergens and causing systemic inflammation is least appreciated. Since CFTR plays a key role in the conductance of anions like Cl^-, loss of CFTR function could affect various basic cellular processes, such as cellular homeostasis, lysosome acidification, and redox balance. CFTR aids in endotoxin tolerance by regulating Toll-like receptor-mediated signaling resulting in uncontrolled activation of innate immune cells. Although leukocytes of CF patients are hyperactivated, they exhibit compromised phagosome activity thus favouring the orchestration of sepsis from defective pathogen clearance. This review will emphasize the importance of innate immunity and systemic inflammatory response in the development of CF and other CFTR-associated pathologies.

Milk kefir drink may not reduce depression in patients with non-alcoholic fatty liver disease: secondary outcome analysis of a randomized, single-blinded, controlled clinical trial

BACKGROUND

Depression is prevalent among individuals with non-alcoholic fatty liver disease (NAFLD) and can cause poor health outcomes. Moreover, a solid bilateral association between NAFLD and depression has been shown, which may alleviate by kefir consumption. Thus, we aimed to investigate the effect of milk kefir drinks on the depression status of individuals with NAFLD.

METHODS

In a secondary outcome analysis of a randomized, single-blinded, controlled clinical trial, 80 adults with grades 1 to 3 of NAFLD were included in an 8-week intervention. Participants were randomly assigned to Diet or Diet + kefir groups to either follow a low-calorie diet or a low-calorie diet along with a 500 cc milk kefir drink daily. The participants' demographic, anthropometric, dietary, and physical data were recorded before and after the study. Depression status was assessed using the Persian format of the second version of the Beck Depression Inventory (BDI-II-Persian) at the baseline and after 8 weeks of intervention.

RESULTS

Overall, 80 participants aged 42.87 ± 10.67 years were included in the analysis. The data on the baseline demographic, dietary, and physical activity of the groups were not significantly different. During the study, participants in Diet + Kefir group had a significantly decreased energy (P = 0.02), carbohydrate (P = 0.4), and fat consumption (P = 0.4). However, during the study, the depression score was not significantly reduced in the Diet group, the Diet + Kefir group showed a significant reduction in depression (P = 0.02). However, between-group analyses for changes in depression were not significant (P = 0.59).

CONCLUSION

Consumption of milk kefir drink for 8 weeks may not reduce depression symptoms in adults with NAFLD.

TRIAL REGISTRATION

The trial was registered at IRCT.ir as IRCT20170916036204N6 (August 2018).

How far are we from an approved drug for non-alcoholic steatohepatitis?

INTRODUCTION

Metabolic associated fatty liver disease (MAFLD) previously known but still debatable, as non-alcoholic fatty liver disease (NAFLD) is one of the main causes of chronic liver disease and subsequent cirrhosis worldwide, accounting for around 30% of liver diseases. The change in its nomenclature has been brought about by the novel discoveries regarding its pathogenesis, in which metabolic dysfunction plays the most important role. It is widely known that for every disease, the treatment should always be targeted toward the underlying etiology and pathogenesis.

AREAS COVERED

MAFLD/NAFLD pathogenesis is heterogeneous, and includes multiple gene polymorphisms, presence of insulin resistance, as well as concomitant diseases that contribute to the disease onset and progression. As a result of this, even though lifestyle modification (owing to metabolic abnormalities) is the first line of treatment, multiple drugs have been tested to target each of the known pathways leading to MAFLD/NAFLD and progression of steatohepatitis. We aim to review the most relevant information regarding previous and ongoing research and recommendations regarding treatment of MAFLD/NAFLD.

EXPERT OPINION

Combination therapies associated to weight loss and exercise will be the optimal approach for these patients. It is important to evaluate each patient to select the specific combination according to patient characteristics.

Dietary Phenolic Compounds: Their Health Benefits and Association with the Gut Microbiota

Oxidative stress causes various diseases, such as type II diabetes and dyslipidemia, while antioxidants in foods may prevent a number of diseases and delay aging by exerting their effects in vivo. Phenolic compounds are phytochemicals such as flavonoids which consist of flavonols, flavones, flavanonols, flavanones, anthocyanidins, isoflavones, lignans, stilbenoids, curcuminoids, phenolic acids, and tannins. They have phenolic hydroxyl groups in their molecular structures. These compounds are present in most plants, are abundant in nature, and contribute to the bitterness and color of various foods. Dietary phenolic compounds, such as quercetin in onions and sesamin in sesame, exhibit antioxidant activity and help prevent cell aging and diseases. In addition, other kinds of compounds, such as tannins, have larger molecular weights, and many unexplained aspects still exist. The antioxidant activities of phenolic compounds may be beneficial for human health. On the other hand, metabolism by intestinal bacteria changes the structures of these compounds with antioxidant properties, and the resulting metabolites exert their effects in vivo. In recent years, it has become possible to analyze the composition of the intestinal microbiota. The augmentation of the intestinal microbiota by the intake of phenolic compounds has been implicated in disease prevention and symptom recovery. Furthermore, the “brain–gut axis”, which is a communication system between the gut microbiome and brain, is attracting increasing attention, and research has revealed that the gut microbiota and dietary phenolic compounds affect brain homeostasis. In this review, we discuss the usefulness of dietary phenolic compounds with antioxidant activities against some diseases, their biotransformation by the gut microbiota, the augmentation of the intestinal microflora, and their effects on the brain–gut axis.

Acupuncture improved hepatic steatosis in HFD-induced NAFLD rats by regulating intestinal microbiota

Background

Intestinal dysbiosis has been increasingly implicated in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Acupuncture has been shown to have beneficial effects on NAFLD, but the mechanism is not yet clear. This study explores the potential beneficial effects of acupuncture on intestinal microbiota in NAFLD.

Methods

An NAFLD model in Sprague Dawley rats was established using a high-fat diet (HFD) for 10  weeks. NAFLD rats were randomly divided into control, model, and acupuncture groups. Following acupuncture treatment over 6 weeks, automated biochemical analysis was used to measure serum lipid metabolism parameters, including levels of alanine transferase, aspartate transferase, alkaline phosphatase, total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. The level of serum inflammatory factors interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) were measured by enzyme-linked immunosorbent assay. The characteristics of steatosis were evaluated using quantitative computed tomography, hematoxylin and eosin staining, and Oil Red O staining in the liver, while the intestinal microbiota was determined using 16S rRNA gene sequencing.

Results

Acupuncture decreased the systemic inflammatory response, ameliorated dyslipidemia, and improved liver function indexes in NAFLD model rats. Tomography and staining indicated that acupuncture reduced steatosis and infiltration of inflammatory cells in the liver. 16S rRNA analysis showed that acupuncture reduced the Firmicutes to Bacteroidetes (F/B) ratio, increased the abundance of microbiota, including Bacteroidales_S24-7_group, Prevotellaceae, Bacteroidaceae, Blautia, norank_f_Bacteroidales_S24-7_group, Bacteroides, and Prevotella_9, and decreased the abundance of Ruminococcaceae_UCG-014. Correlation analysis suggested a close correlation between lipid metabolism, inflammation factors, hepatic steatosis, and the changed intestinal microbiota.

Conclusion

Acupuncture can significantly improve lipid metabolism and the systemic inflammatory response in HFD-induced NAFLD rats, potentially by regulating intestinal microbiota composition.

Baicalein alleviates non-alcoholic fatty liver disease in mice by ameliorating intestinal barrier dysfunction

Non-alcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease, and its pathological development is closely related to the gut-liver axis. The intestinal barrier, an important component of the gut-liver axis, can prevent gut microbes and endotoxins from entering the liver. Intestinal barrier function is impaired in patients with NAFLD. Baicalein, which is the main flavonoid in Scutellariae Radix, can improve NAFLD. However, whether baicalein alleviates NAFLD by ameliorating intestinal barrier dysfunction remains unclear. In this study, a methionine-choline deficient (MCD) diet-induced NAFLD mouse model is used. The effects of baicalein on lipid accumulation, inflammation and the intestinal barrier in MCD-fed mice were evaluated by detecting blood lipid levels, lipid accumulation, liver pathological changes, inflammatory factors, inflammatory signaling pathways, the three main short-chain fatty acids (acetate, propionate and butyrate), intestinal permeability and intestinal tight junction protein expression. Compared with the MCD-only group, baicalein intake decreased the serum and liver lipid levels. Moreover, the accumulation of lipid droplets and steatosis in the liver were also alleviated; all these results demonstrated that baicalein could alleviate NAFLD. Meanwhile, the levels of inflammatory cytokines decreased in the baicalein group. Further investigation of the mucosal permeability to 4 kDa fluorescein isothiocyanate-dextran, concentrations of short-chain fatty acids in feces, and the expression of intestinal zonula occluden 1 and claudin-1 indicated that a baicalein diet could decrease the intestinal permeability caused by a MCD diet. Moreover, the protein levels of p-NF-κB p65 and the ratio of p-NF-κB p65/NF-κB p65 increased, and IκB-α and PPARα decreased in NAFLD mice, while the administration of baicalein could alleviate these changes. The above results indicated that the mechanism of baicalein in the alleviation of NAFLD lies in the regulation of the intestinal barrier.

The role of the gut microbiota in depressive-like behavior induced by chlorpyrifos in mice

Chlorpyrifos (CPF) is associated with depression, cognitive dysfunction, and other neurological disorders. Increasing evidence has suggested that the gut microbiota plays a vital role in regulating the development of depression. However, it is unknown whether gut microbiota is associated with CPF-related depression. This study aimed to explore the effect of CPF on depressive-like behavior in mice and investigated the role of gut microbiota in this behavior. In our study, we selected fifty male C57BL/6 J mice for the model and subjected them to CPF poisoning by gavage for 14 days. The depressive-like behaviors of mice were assessed by the open field test (OFT), sucrose preference test (SPT), and forced swimming test (FST). Furthermore, we selected the high-dose group (CPF10) with obvious changes in depressive-like behaviors for the hippocampus and colon histopathological analysis, examined the changes in the gut microbiota by 16 S rRNA sequencing, screened the different microbiota among groups by linear discriminant analysis effect size (LEfSe), analyzed the correlation between intestinal bacteria and depression-like behavior indicators by Spearman analysis, and evaluated the predictive ability of different bacteria to CPF-induced depressive-like behavior using the receiver operator characteristic (ROC) curve. The results showed that CPF caused depressive-like behaviors with pathological changes in the hippocampus and colon. CPF induced changes in gut microbiota, including 49 differential bacteria. Among the top 10 abundant bacteria, Actinobacteria and Deferribacteres were increased, and Cyanobacteria, Patescibacteria and Verrucomicrobia were decreased at the phylum level. Muribaculum, Ruminococcaceae.UCG.014 and uncultured Bacteroides bacterium were decreased at the genus level. Correlation analysis demonstrated that 18 differentially abundant bacteria were correlated with CPF-induced depression. ROC curves revealed that Deferribacteres, Mucispirillum, Rikenella and GCA900066575 are potential biomarkers for depression caused by CPF. These findings will provide an experimental basis for the neurological health of the pesticide-exposed population.

Imbalanced gut microbiota predicts and drives the progression of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis in a fast-food diet mouse model

Nonalcoholic fatty liver disease (NAFLD) is multifactorial in nature, affecting over a billion people worldwide. The gut microbiome has emerged as an associative factor in NAFLD, yet mechanistic contributions are unclear. Here, we show fast food (FF) diets containing high fat, added cholesterol, and fructose/glucose drinking water differentially impact short- vs. long-term NAFLD severity and progression in conventionally-raised, but not germ-free mice. Correlation and machine learning analyses independently demonstrate FF diets induce early and specific gut microbiota changes that are predictive of NAFLD indicators, with corresponding microbial community instability relative to control-fed mice. Shotgun metagenomics showed FF diets containing high cholesterol elevate fecal pro-inflammatory effectors over time, relating to a reshaping of host hepatic metabolic and inflammatory transcriptomes. FF diet-induced gut dysbiosis precedes onset and is highly predictive of NAFLD outcomes, providing potential insights into microbially-based pathogenesis and therapeutics.

Commensal microbiota modulates phenotypic characteristics and gene expression in piglet Peyer's patches

The gastrointestinal tract contains a complex microbial community. Peyer's patches (PPs) play an important role in inducing mucosal immune responses in the gastrointestinal tract. However, little is known about the effect of commensal microbiota on the host's PPs. Here, we analyzed the phenotypic-to-transcriptome changes in the intestine PPs of specific pathogen-free (SPF) and germ-free (GF) piglets (fed in an environment with and without commensal microbiota, respectively) to elucidate the role of commensal microbiota in host intestine mucosal immunity. Analyses of anatomical and histological characteristics showed that commensal microbiota deficiency led to PP hypoplasia, especially regarding B and T cells. A total of 12,444 mRNAs were expressed in 12 libraries; 2,156 and 425 differentially expressed (DE) mRNAs were detected in the jejunal PP (JPP) and ileal PP (IPP), respectively (SPF vs. GF). The shared DE mRNAs of the JPP and IPP were mainly involved in basic physiological and metabolic processes, while the specific DE mRNAs were enriched in regulating immune cells in the JPP and microbial responses and cellular immunity in the IPP. Commensal microbiota significantly modulated the expression of genes related to B-cell functions, including activation, proliferation, differentiation, apoptosis, receptor signaling, germinal center formation, and IgA isotype class switching, particularly in the JPP. TLR4 pathway-related genes were induced in response to microbial colonization and in LPS/SCFA-treated B cells. We also detected 69 and 21 DE lncRNAs in the JPP and IPP, respectively, and four one-to-one lncRNA-mRNA pairs were identified. These findings might represent key regulatory axes for host intestine mucosal immunity development during microbial colonization. Overall, the findings of this study revealed that commensal microbiota modulated phenotypic characteristics and gene expression in the piglet intestine PPs and underscored the importance of early microbial colonization for host mucosal immunity development.

Yinchen Linggui Zhugan decoction ameliorates high fat diet-induced nonalcoholic fatty liver disease by modulation of SIRT1/Nrf2 signaling pathway and gut microbiota

Yinchen Linggui Zhugan decoction (YLZD) is an effective and classical traditional herbal prescription for treating the nonalcoholic fatty liver disease (NAFLD) and has been proven to be effective in the regulation of lipid metabolism disorder and attenuate inflammation for a NAFLD rat model. However, the exact underlying mechanism has not been elucidated. In the current study, a NAFLD rat model was established using a high-fat diet (HFD) for 10 weeks, followed by YLZD treatment with 1.92 g/kg/day for 4 weeks to explore the mechanisms of YLZD. Our results showed that YLZD decreased the hepatic lipid deposition, restored the liver tissue pathological lesions, inhibited the expression of oxidative stress, and decreased the inflammatory cytokines levels. Meanwhile, the genes and proteins expressions of SIRT1/Nrf2 signaling pathway together with downstream factors including HO-1 and NQO1 were elevated in the YLZD treated NAFLD rats. For further elaborating the upstream mechanism, short-chain fatty acids (SCFAs) in serum and feces were measured by liquid chromatograph mass spectrometer and gas chromatograph mass spectrometer, and the differences in gut microbiota of rats in each group were analyzed through high-throughput sequencing of 16S rRNA. The results demonstrated that the contents of butyric acid (BA) and total SCFAs in YLZD-treated NAFLD rats were significantly increased in serum and feces. 16S rRNA sequencing analysis illustrated that YLZD intervention led to a modification of the gut microbiota composition, with a decrease of Oribacterium, Lactobacillus and the ratio of Firmicutes/Bacteroides, as well as the increase in SCFAs-producing bacteria such as Christensenellaceae, Clostridia, Muribaculaceae, and Prevotellaceae. Spearman rank correlation analysis indicated that BA and total SCFAs were negatively co-related with oxidative stress-related factors and inflammatory cytokines, while they were positively co-related with SIRT1/Nrf2 pathway related genes and proteins. Furthermore, in vitro study confirmed that BA effectively reduced oxidative stress by activating SIRT1/Nrf2 signaling pathway in L02 cells. Together, the present data revealed YLZD could ameliorate HFD-induced NAFLD in rats by the modulation of SIRT1/Nrf2 signaling pathway and gut microbiota.

Male zooid extracts of Antheraea pernyi ameliorates non-alcoholic fatty liver disease and intestinal dysbacteriosis in mice induced by a high-fat diet

The male zooid of Antheraea pernyi (A. pernyi) accumulates several nutrients and physiological activity-related substances for reproduction. Some components in the extracts of the male zooid of A. pernyi (EMZAP) have several functions, such as protecting the liver, enhancing immunity, antiatheroscloresis, anti-aging, and antitumor effects. In this study, we investigated the ameliorating effects on high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD). The EMZAP treatment could ameliorate NAFLD and effectively decrease the serum total cholesterol, triglyceride and low-density lipoprotein levels and a significant increase in serum high-density lipoprotein levels was observed. Additionally, the EMZAP treatment reduced the levels of liver-function enzymes and pro-inflammatory cytokines (i.e., IL-6, IL-8, TNF-α, TGF-β₁) and also the oxidative stress indices and regulated the expression of genes associated with fatty acid metabolism (SREBP-1c, PPARα, ACOX-1, CPT-1) in the liver to prevent the development of NAFLD. Furthermore, EMZAP enhanced the diversity and richness of the beneficial intestinal microbes, suggesting its potential as a dietary supplement and functional food to combat NAFLD induced by HFD.

The gut microbiota–bile acid axis: A potential therapeutic target for liver fibrosis

Liver fibrosis involves the proliferation and deposition of extracellular matrix on liver tissues owing to various etiologies (including viral, alcohol, immune, and metabolic factors), ultimately leading to structural and functional abnormalities in the liver. If not effectively treated, liver fibrosis, a pivotal stage in the path to chronic liver disease, can progress to cirrhosis and eventually liver cancer; unfortunately, no specific clinical treatment for liver fibrosis has been established to date. In liver fibrosis cases, both the gut microbiota and bile acid metabolism are disrupted. As metabolites of the gut microbiota, bile acids have been linked to the progression of liver fibrosis via various pathways, thus implying that the gut microbiota–bile acid axis might play a critical role in the progression of liver fibrosis and could be a target for its reversal. Therefore, in this review, we examined the involvement of the gut microbiota–bile acid axis in liver fibrosis progression to the end of discovering new targets for the prevention, diagnosis, and therapy of chronic liver diseases, including liver fibrosis.

Unlocking the Potential of the Human Microbiome for Identifying Disease Diagnostic Biomarkers

The human microbiome encodes more than three million genes, outnumbering human genes by more than 100 times, while microbial cells in the human microbiota outnumber human cells by 10 times. Thus, the human microbiota and related microbiome constitute a vast source for identifying disease biomarkers and therapeutic drug targets. Herein, we review the evidence backing the exploitation of the human microbiome for identifying diagnostic biomarkers for human disease. We describe the importance of the human microbiome in health and disease and detail the use of the human microbiome and microbiota metabolites as potential diagnostic biomarkers for multiple diseases, including cancer, as well as inflammatory, neurological, and metabolic diseases. Thus, the human microbiota has enormous potential to pave the road for a new era in biomarker research for diagnostic and therapeutic purposes. The scientific community needs to collaborate to overcome current challenges in microbiome research concerning the lack of standardization of research methods and the lack of understanding of causal relationships between microbiota and human disease.

Combined Use of Bicyclol and Berberine Alleviates Mouse Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), is a liver disease worldwide without approved therapeutic drugs. Anti-inflammatory and hepatoprotective drug bicyclol and multi-pharmacological active drug berberine, respectively, have shown beneficial effects on NAFLD in murine nutritional models and patients, though the therapeutic mechanisms remain to be illustrated. Here, we investigated the combined effects of bicyclol and berberine on mouse steatosis induced by Western diet (WD), and NASH induced by WD/CCl₄. The combined use of these was rather safe and better reduced the levels of transaminase in serum and triglycerides and cholesterol in the liver than their respective monotherapy, accompanied with more significantly attenuating hepatic inflammation, steatosis, and ballooning in mice with steatosis and NASH. The combined therapy also significantly inhibited fibrogenesis, characterized by the decreased hepatic collagen deposition and fibrotic surface. As per mechanism, bicyclol enhanced lipolysis and β-oxidation through restoring the p62-Nrf2-CES2 signaling axis and p62-Nrf2-PPARα signaling axis, respectively, while berberine suppressed de novo lipogenesis through downregulating the expression of acetyl-CoA carboxylase and fatty acid synthetase, along with enrichment of lipid metabolism-related Bacteroidaceae (family) and Bacteroides (genus). Of note, the combined use of bicyclol and berberine did not influence each other but enhanced the overall therapeutic role in the amelioration of NAFLD. Conclusion: Combined use of bicyclol and berberine might be a new available strategy to treat NAFLD.

Polydextrose Alleviates Adipose Tissue Inflammation and Modulates the Gut Microbiota in High-Fat Diet-Fed Mice

The soluble dietary fiber polydextrose (PDX) is a randomly linked glucose oligomer containing small amounts of sorbitol and citric acid and is widely used in the food industry. However, whether PDX can prevent and treat obesity in high-fat diet (HFD)-fed mice has not been directly investigated, and further studies are needed to better understand the complex interactions among PDX, adipose tissue inflammation and the gut microbiota. In the present study, PDX reduced body weight, fasting blood glucose (FBG), adipose tissue accumulation, adipocyte hypertrophy, serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels in HFD-fed mice. Moreover, PDX alleviated serum lipopolysaccharide (LPS) levels and macrophage infiltration in epididymal adipose tissue and resulted in macrophage polarization toward the M2 phenotype. Gut microbiota analysis revealed that PDX promoted the growth of beneficial microbes such as Bacteroides, Parabacteroides, Alloprevotella, Muribaculum, Akkermansia, Ruminococcaceae_UCG-014 and UBA1819 in obese mice, which were negatively correlated with subcutaneous fat, epididymal fat, body weight, FBG, serum TC, HDL-C, LDL-C and LPS levels. Our results indicates that PDX can prevent and treat obesity in HFD-fed mice, specifically in alleviating glucolipid metabolism disorders and adipose tissue inflammation, which may be mediated by modulating the structure of the gut microbiota. Therefore, PDX may become a promising nondrug therapy for obesity.

Microbiota in Pancreatic Diseases: A Review of the Literature

The gut microbiota is a critical element in the balance between human health and disease. Its impairment, defined as dysbiosis, is associated with gastroenterological and systemic diseases. Pancreatic secretions are involved in the composition and changes of the gut microbiota, and the gut microbiota may colonize the pancreatic parenchyma and be associated with the occurrence of diseases. The gut microbiota and the pancreas influence each other, resulting in a "gut microbiota-pancreas axis". Moreover, the gut microbiota may be involved in pancreatic diseases, both through direct bacterial colonization and an indirect effect of small molecules and toxins derived from dysbiosis. Pancreatic diseases such as acute pancreatitis, chronic pancreatitis, autoimmune pancreatitis, and pancreatic cancer are common gastroenterological diseases associated with high morbidity and mortality. The involvement of the microbiota in pancreatic diseases is increasingly recognized. Therefore, modifying the intestinal bacterial flora could have important therapeutic implications on these pathologies. The aim of this study is to review the literature to evaluate the alterations of the gut microbiota in pancreatic diseases, and the role of the microbiota in the treatment of these diseases.