The Role of Short-Chain Fatty Acids and Bile Acids in Intestinal and Liver Function, Inflammation, and Carcinogenesis

Advances in the mechanism of action of short-chain fatty acids in psoriasis

Psoriasis is a prevalent chronic inflammatory and immunological disorder. Its lesions are present as scaly erythema or plaques. Disruptions in the body's immune system play a significant role in developing psoriasis. Recent evidence suggests a potential role of the gut microbiome in autoimmune diseases. Short-chain fatty acids (SCFAs) are the primary metabolites created by gut microbes and play a crucial fuction in autoimmunity. SCFAs act on various cells by mediating signaling to participate in host physiological and pathological processes. These processes encompass body metabolism, maintenance of intestinal barrier function, and immune system modulation. SCFAs can regulate immune cells to enhance the body's immune function, potentially influencing the prevention and treatment of psoriasis. However, the mechanisms underlying the role of SCFAs in psoriasis remain incompletely understood. This paper examines the relationship between SCFAs and psoriasis, elucidating how SCFAs influence the immune system, inflammatory response, and gut barrier in psoriasis. According to the study, in psoriasis, SCFAs have been shown to regulate neutrophils, macrophages, and dendritic cells in the adaptive immune system, as well as T and B cells in the innate immune system. Additionally, we explore the role of SCFAs in psoriasis by maintaining intestinal barrier function, restoring intestinal ecological homeostasis, and investigating the potential therapeutic benefits of SCFAs for psoriasis.

Gut Microbiota, Deranged Immunity, and Hepatocellular Carcinoma

BACKGROUND

Liver cancer, particularly hepatocellular carcinoma (HCC), is a significant gastrointestinal disease with a mortality rate as high as nearly 80% within five years. The disease's pathophysiology involves deranged immune responses and bile acid metabolism, with the gut microbiota (GM) playing a crucial role. Recent research highlights the potential of GM in influencing HCC treatment outcomes, especially regarding immune checkpoint inhibitors (ICIs). However, few patients currently benefit from ICIs due to a lack of effective response biomarkers.

AIMS AND METHODS

This review aimed to explore the literature on HCC treatment issues, focusing on immune response, bile acid metabolism, and GM dysbiosis. This review included studies from PubMed, Medline, and major gastroenterology and hepatology meetings, using keywords like gut microbiota, immune system, liver cancer, and checkpoint inhibitors.

RESULTS

GM dysbiosis significantly impacts immune response and bile acid metabolism, making it a promising biomarker for ICI response. Modulating GM can enhance ICI treatment efficacy, although more research is needed to confirm its direct therapeutic benefits for HCC.

CONCLUSIONS

GM dysbiosis is integral to liver cancer pathogenesis and treatment response. Its modulation offers promising therapeutic avenues for improving HCC prognosis and response to immunotherapy.

Is There an Interplay between Environmental Factors, Microbiota Imbalance, and Cancer Chemotherapy-Associated Intestinal Mucositis?

Interindividual variation in drug efficacy and toxicity is a significant problem, potentially leading to adverse clinical and economic public health outcomes. While pharmacogenetics and pharmacogenomics have long been considered the primary causes of such heterogeneous responses, pharmacomicrobiomics has recently gained attention. The microbiome, a community of microorganisms living in or on the human body, is a critical determinant of drug response and toxicity. Factors such as diet, lifestyle, exposure to xenobiotics, antibiotics use, illness, and genetics can influence the composition of the microbiota. Changes in the intestinal microbiota are particularly influential in drug responsiveness, especially in cancer chemotherapy. The microbiota can modulate an individual's response to a drug, affecting its bioavailability, clinical effect, and toxicity, affecting treatment outcomes and patient quality of life. For instance, the microbiota can convert drugs into active or toxic metabolites, influencing their efficacy and side effects. Alternatively, chemotherapy can also alter the microbiota, creating a bidirectional interplay. Probiotics have shown promise in modulating the microbiome and ameliorating chemotherapy side effects, highlighting the potential for microbiota-targeted interventions in improving cancer treatment outcomes. This opinion paper addresses how environmental factors and chemotherapy-induced dysbiosis impact cancer chemotherapy gastrointestinal toxicity.

Histone deacetylases and inhibitors in diabetes mellitus and its complications

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, with its prevalence linked to both genetic predisposition and environmental factors. Epigenetic modifications, particularly through histone deacetylases (HDACs), have been recognized for their significant influence on DM pathogenesis. This review focuses on the classification of HDACs, their role in DM and its complications, and the potential therapeutic applications of HDAC inhibitors. HDACs, which modulate gene expression without altering DNA sequences, are categorized into four classes with distinct functions and tissue specificity. HDAC inhibitors (HDACi) have shown efficacy in various diseases, including DM, by targeting these enzymes. The review highlights how HDACs regulate β-cell function, insulin sensitivity, and hepatic gluconeogenesis in DM, as well as their impact on diabetic cardiomyopathy, nephropathy, and retinopathy. Finally, we suggest that targeted histone modification is expected to become a key method for the treatment of diabetes and its complications. The study of HDACi offers insights into new treatment strategies for DM and its associated complications.

Role of Gut Microbial Metabolites in the Pathogenesis of Primary Liver Cancers

Hepatobiliary malignancies, which include hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), are the sixth most common cancers and the third leading cause of cancer-related death worldwide. Hepatic carcinogenesis is highly stimulated by chronic inflammation, defined as fibrosis deposition, and an aberrant imbalance between liver necrosis and nodular regeneration. In this context, the gut-liver axis and gut microbiota have demonstrated a critical role in the pathogenesis of HCC, as dysbiosis and altered intestinal permeability promote bacterial translocation, leading to chronic liver inflammation and tumorigenesis through several pathways. A few data exist on the role of the gut microbiota or bacteria resident in the biliary tract in the pathogenesis of CCA, and some microbial metabolites, such as choline and bile acids, seem to show an association. In this review, we analyze the impact of the gut microbiota and its metabolites on HCC and CCA development and the role of gut dysbiosis as a biomarker of hepatobiliary cancer risk and of response during anti-tumor therapy. We also discuss the future application of gut microbiota in hepatobiliary cancer management.

Mediterranean Diet Adherence, Gut Microbiota and Parkinson's Disease: A Systematic Review

BACKGROUND

There is mounting evidence to suggest that high adherence to the Mediterranean diet (MedDiet) may reduce the risk of age-related diseases, including Parkinson's disease (PD). However, evidence for the role of the MedDiet in the relief of motor and non-motor symptoms in patients with PD remains limited and inconclusive. We provide a systematic review of the effects of the MedDiet on the clinical features of PD using data from randomised controlled trials (RCT) and prospective observational studies.

METHODS

We searched MEDLINE, EMCare, EMBASE, Scopus and PubMed from inception until June 2023. Reference lists and the grey literature were also searched. Human studies with no restriction on language or publication date, examining associations between MedDiet adherence and the symptoms of PD, were included. We employed standard methodological procedures for data extraction and evidence synthesis and used the Quality Criteria Checklist for assessing the studies included.

RESULTS

Four studies from three unique cohorts, including two observational studies (n = 1213) and one RCT (n = 70), met the inclusion criteria. Despite the short study duration reported in all included reports, high MedDiet adherence was associated with changes in the gut microbiota (e.g., increased abundance of short-chain fatty acids producers). These outcomes correlated with a significant improvement in several non-motor symptoms including cognitive dysfunction, dyspepsia and constipation. However, there were no significant changes in diarrhoea, gastrointestinal reflux, abdominal pain and motor symptoms.

CONCLUSION

High MedDiet adherence may be associated with significant improvement in global cognition and several gastrointestinal symptoms, possibly associated to changes in gut microbiota composition. Further studies are warranted to clarify potential cause-and-effect relationships and to elucidate MedDiet impact on motor symptoms.

Influence of gut microbiome on metabolic diseases: a new perspective based on microgravity

Purpose

Microgravity, characterized by gravity levels of 10-3-10-6g, has been found to significantly impair various physiological systems in astronauts, including cardiovascular function, bone density, and metabolism. With the recent surge in human spaceflight, understanding the impact of microgravity on biological health has become paramount.

Methods

A comprehensive literature search was performed using the PubMed database to identify relevant publications pertaining to the interplay between gut microbiome, microgravity, space environment, and metabolic diseases.

Results

This comprehensive review primarily focuses on the progress made in investigating the gut microbiome and its association with metabolic diseases under microgravity conditions. Microgravity induces notable alterations in the composition, diversity, and functionality of the gut microbiome. These changes hold direct implications for metabolic disorders such as cardiovascular disease (CVD), bone metabolism disorders, energy metabolism dysregulation, liver dysfunction, and complications during pregnancy.

Conclusion

This novel perspective is crucial for preparing for deep space exploration and interstellar migration, where understanding the complex interplay between the gut microbiome and metabolic health becomes indispensable.

Unveiling the gut-eye axis: how microbial metabolites influence ocular health and disease

The intricate interplay between the gut microbiota and ocular health has surpassed conventional medical beliefs, fundamentally reshaping our understanding of organ interconnectivity. This review investigates into the intricate relationship between gut microbiota-derived metabolites and their consequential impact on ocular health and disease pathogenesis. By examining the role of specific metabolites, such as short-chain fatty acids (SCFAs) like butyrate and bile acids (BAs), herein we elucidate their significant contributions to ocular pathologies, thought-provoking the traditional belief of organ sterility, particularly in the field of ophthalmology. Highlighting the dynamic nature of the gut microbiota and its profound influence on ocular health, this review underlines the necessity of comprehending the complex workings of the gut-eye axis, an emerging field of science ready for further exploration and scrutiny. While acknowledging the therapeutic promise in manipulating the gut microbiome and its metabolites, the available literature advocates for a targeted, precise approach. Instead of broad interventions, it emphasizes the potential of exploiting specific microbiome-related metabolites as a focused strategy. This targeted approach compared to a precision tool rather than a broad-spectrum solution, aims to explore the therapeutic applications of microbiome-related metabolites in the context of various retinal diseases. By proposing a nuanced strategy targeted at specific microbial metabolites, this review suggests that addressing specific deficiencies or imbalances through microbiome-related metabolites might yield expedited and pronounced outcomes in systemic health, extending to the eye. This focused strategy holds the potential in bypassing the irregularity associated with manipulating microbes themselves, paving a more efficient pathway toward desired outcomes in optimizing gut health and its implications for retinal diseases.

Risk of cancer in patients with bile acid diarrhoea: a Danish nationwide matched cohort study

OBJECTIVE

Bile acid diarrhoea is a common cause of chronic diarrhoea. Increased levels of potentially carcinogenic bile acids in faeces, theoretically, may increase the risk of colorectal cancer in particular, but the long-term disease course is unknown. We aimed to investigate the overall and site-specific cancer risk in bile acid diarrhoea.

DESIGN

Adult patients with bile acid diarrhoea were identified using nationwide Danish registries from 2003 to 2020 by a diagnostic gold-standard 75-selenium tauroselcholic acid procedure followed within 6 months by sequestrant prescription. The risk of overall and site-specific cancers in cases with bile acid diarrhoea was compared with sex, age and comorbidity-adjusted matched controls. A competing risk model estimated cumulative incidence functions and cause-specific HRs.

RESULTS

We identified 2260 patients with bile acid diarrhoea with a mean follow-up of 5.5 years (SD 4.2). The overall cancer risk was increased by an HR of 1.32 (95% CI 1.12 to 1.54). The risk of site-specific cancer was increased in 3 of 10 cancer groups: haematological, HR 2.41 (1.36 to 4.02); skin, HR 1.33 (1.01 to 1.71); and male genital cancers, HR 1.85 (1.11 to 2.92). No increased risk of colorectal cancer was detected in patients with bile acid diarrhoea, HR 0.73 (0.34 to 1.63).

CONCLUSIONS

Bile acid diarrhoea was associated with an increased overall risk of cancer, especially haematological cancers, but the risk of colorectal cancer was not increased. The lack of a diagnostic code for bile acid diarrhoea and potential residual confounding are limitations, and the findings should be replicated in other cohorts.

Short-Chain Fatty Acids and Human Health: From Metabolic Pathways to Current Therapeutic Implications

The gastrointestinal tract is home to trillions of diverse microorganisms collectively known as the gut microbiota, which play a pivotal role in breaking down undigested foods, such as dietary fibers. Through the fermentation of these food components, short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate are produced, offering numerous health benefits to the host. The production and absorption of these SCFAs occur through various mechanisms within the human intestine, contingent upon the types of dietary fibers reaching the gut and the specific microorganisms engaged in fermentation. Medical literature extensively documents the supplementation of SCFAs, particularly butyrate, in the treatment of gastrointestinal, metabolic, cardiovascular, and gut-brain-related disorders. This review seeks to provide an overview of the dynamics involved in the production and absorption of acetate, propionate, and butyrate within the human gut. Additionally, it will focus on the pivotal roles these SCFAs play in promoting gastrointestinal and metabolic health, as well as their current therapeutic implications.

Effects of dietary arsenic exposure on liver metabolism in mice

Arsenic, a ubiquitous environmental toxicant with various forms and complex food matrix interactions, can reportedly exert differential effects on the liver compared to drinking water exposure. To examine its specific liver-related harms, we targeted the liver in C57BL/6 J mice (n=48, 8-week-old) fed with arsenic-contaminated food (30 mg/kg) for 60 days, mimicking the rice arsenic composition observed in real-world scenarios (iAsV: 7.3%, iAsIII: 72.7%, MMA: 1.0%, DMA: 19.0%). We then comprehensively evaluated liver histopathology, metabolic changes, and the potential role of the gut-liver axis using human hepatocellular carcinoma cells (HepG2) and microbiota/metabolite analyses. Rice arsenic exposure significantly altered hepatic lipid (fatty acids, glycerol lipids, phospholipids, sphingolipids) and metabolite (glutathione, thioneine, spermidine, inosine, indole-derivatives, etc.) profiles, disrupting 33 metabolic pathways (bile secretion, unsaturated fatty acid biosynthesis, glutathione metabolism, ferroptosis, etc.). Pathological examination revealed liver cell necrosis/apoptosis, further confirmed by ferroptosis induction in HepG2 cells. Gut microbiome analysis showed enrichment of pathogenic bacteria linked to liver diseases and depletion of beneficial strains. Fecal primary and secondary bile acids, short-chain fatty acids, and branched-chain amino acids were also elevated. Importantly, mediation analysis revealed significant correlations between gut microbiota, fecal metabolites, and liver metabolic alterations, suggesting fecal metabolites may mediate the impact of gut microbiota and liver metabolic disorders. Gut microbiota and its metabolites may play significant roles in arsenic-induced gut-liver injuries. Overall, our findings demonstrate that rice arsenic exposure triggers oxidative stress, disrupts liver metabolism, and induces ferroptosis.

Butyrate induces oxidative burst mediated apoptosis via Glucose-6-Phosphate Dehydrogenase (G6PDH) in macrophages during mycobacterial infection

Microorganisms present in the gut modulate host defence responses against infections in order to maintain immune homeostasis. This host-microbe crosstalk is regulated by gut metabolites. Butyrate is one such small chain fatty acid produced by gut microbes upon fermentation that has the potential to influence immune responses. Here we investigated the role of butyrate in macrophages during mycobacterial infection. Results demonstrate that butyrate significantly suppresses the growth kinetics of mycobacteria in culture medium as well as inhibits mycobacterial survival inside macrophages. Interestingly, butyrate alters the pentose phosphate pathway by inducing higher expression of Glucose-6-Phosphate Dehydrogenase (G6PDH) resulting in a higher oxidative burst via decreased Sod-2 and increased Nox-2 (NADPH oxidase-2) expression. Butyrate-induced G6PDH also mediated a decrease in mitochondrial membrane potential. This in turn lead to an induction of apoptosis as measured by lower expression of the anti-apoptotic protein Bcl-2 and a higher release of Cytochrome C as a result of induction of apoptosis. These results indicate that butyrate alters the metabolic status of macrophages and induces protective immune responses against mycobacterial infection.

Microbiome-Metabolomic Analysis Revealed the Immunoprotective Effects of the Extract of Vanilla planifolia Andrew (EVPA) on Immunosuppressed Mice

This study investigated the immunoprotective effects of the extract of Vanilla planifolia Andrew (EVPA) on cyclophosphamide (Cy)-induced immunosuppression in mice. The results show that EVPA administration significantly alleviated the immune damage induced by Cy, as evidenced by an improved body weight, organ index, and colonic injury. A further analysis of microbial diversity revealed that the EVPA primarily increased the abundance of the beneficial bacteria Verrucomicrobiota, Lactobacillaceae, and Lactobacillus while decreasing Akkermansiaceae, Akkermansia, Romboutsia, and Lactococcus, thereby ameliorating the microbial dysbiosis caused by Cy. A metabolomic analysis revealed significant alterations in the microbial metabolite levels after EVPA treatment, including urobilinogen, formamidopyrimidine nucleoside triphosphate, Cer (d18:1/18:0), pantetheine, and LysoPC (15:0/0:0). These altered metabolites are associated with pathways related to sphingolipid metabolism, carbapenem biosynthesis, pantothenate and CoA biosynthesis, glycerophospholipid metabolism, and porphyrin metabolism. Furthermore, significant correlations were observed between certain microbial groups and the differential metabolites. These findings provide new insights into the immunomodulatory effects of EVPA on the intestinal microbiota and metabolism, laying the foundation for more extensive utilization.

A new perspective on gut-lung axis affected through resident microbiome and their implications on immune response in respiratory diseases

The highly diverse microbial ecosystem of the human body colonizes the gastrointestinal tract has a profound impact on the host's immune, metabolic, endocrine, and other physiological processes, which are all interconnected. Specifically, gut microbiota has been found to play a crucial role in facilitating the adaptation and initiation of immune regulatory response through the gastrointestinal tract affecting the other distal mucosal sites such as lungs. A tightly regulated lung-gut axis during respiratory ailments may influence the various molecular patterns that instructs priming the disease severity to dysregulate the normal function. This review provides a comprehensive summary of current research on gut microbiota dysbiosis in respiratory diseases including asthma, pneumonia, bronchopneumonia, COPD during infections and cancer. A complex-interaction among gut microbiome, associated metabolites, cytokines, and chemokines regulates the protective immune response activating the mucosal humoral and cellular response. This potential mechanism bridges the regulation patterns through the gut-lung axis. This paper aims to advance the understanding of the crosstalk of gut-lung microbiome during infection, could lead to strategize to modulate the gut microbiome as a treatment plan to improve bad prognosis in various respiratory diseases.

Bifidobacterium longum promotes postoperative liver function recovery in patients with hepatocellular carcinoma

Timely liver function recovery (LFR) is crucial for postoperative hepatocellular carcinoma (HCC) patients. Here, we established the significance of LFR on patient long-term survival through retrospective and prospective cohorts and identified a key gut microbe, Bifidobacterium longum, depleted in patients with delayed recovery. Fecal microbiota transfer from HCC patients with delayed recovery to mice similarly impacted recovery time post hepatectomy. However, oral gavage of B. longum improved liver function and repair in these mice. In a clinical trial of HCC patients, orally administering a probiotic bacteria cocktail containing B. longum reduced the rates of delayed recovery, shortened hospital stays, and improved overall 1-year survival. These benefits, attributed to diminished liver inflammation, reduced liver fibrosis, and hepatocyte proliferation, were associated with changes in key metabolic pathways, including 5-hydroxytryptamine, secondary bile acids, and short-chain fatty acids. Our findings propose that gut microbiota modulation can enhance LFR, thereby improving postoperative outcomes for HCC patients.

The health benefits of dietary short-chain fatty acids in metabolic diseases

Short-chain fatty acids (SCFAs) are a subset of fatty acids that play crucial roles in maintaining normal physiology and developing metabolic diseases, such as obesity, diabetes, cardiovascular disease, and liver disease. Even though dairy products and vegetable oils are the direct dietary sources of SCFAs, their quantities are highly restricted. SCFAs are produced indirectly through microbial fermentation of fibers. The biological roles of SCFAs in human health and metabolic diseases are mainly due to their receptors, GPR41 and GPR43, FFAR2 and FFAR3. Additionally, it has been demonstrated that SCFAs modulate DNMTs and HDAC activities, inhibit NF-κB-STAT signaling, and regulate G(i/o)βγ-PLC-PKC-PTEN signaling and PPARγ-UCP2-AMPK autophagic signaling, thus mitigating metabolic diseases. Recent studies have uncovered that SCFAs play crucial roles in epigenetic modifications of DNAs, RNAs, and post-translational modifications of proteins, which are critical regulators of metabolic health and diseases. At the same time, dietary recommendations for the purpose of SCFAs have been proposed. The objective of the review is to summarize the most recent research on the role of dietary SCFAs in metabolic diseases, especially the signal transduction of SCFAs in metabolic diseases and their functional efficacy in different backgrounds and models of metabolic diseases, at the same time, to provide dietary and nutritional recommendations for using SCFAs as food ingredients to prevent metabolic diseases.

Clostridium butyricum Ameliorates the Effect of Coprophagy Prevention on Hepatic Lipid Synthesis in Rabbits via the Gut-Liver Axis

Coprophagy prevention (CP) affects the growth performance, hepatic lipid synthesis, and gut microbiota in rabbits. Supplementation with Clostridium butyricum (C. butyricum, Strain number: CCTCC M 2019962) has been found to improve growth performance in rabbits. However, it remains unknown whether C. butyricum can ameliorate the effects of CP on hepatic lipid synthesis and the underlying mechanisms are yet to be elucidated. Therefore, this study aimed to investigate the impact of CP on hepatic lipid synthesis and the underlying mechanism based on the gut-liver axis. The findings revealed that supplementation with C. butyricum could reverse CP-related growth performance, lipid accumulation, bile acid synthesis, and inflammation. Furthermore, C. butyricum exerted protective effects on the gut by preserving intestinal barrier integrity and modulating gut microbiota composition; these factors may represent potential mechanisms through which C. butyricum improves CP-related outcomes. Specifically, C. butyricum reshaped the microbiota by increasing butyric acid levels, thereby maintaining secondary bile acid (deoxycholic acid, chenodeoxycholic acid) balance and attenuating the inhibitory effects of the FXR/SHP pathway on lipid synthesis (SREBP1c/ApoA1). Moreover, the activation of butyrate/GPR43pathway by C. butyricum reduced damage to the intestinal barrier (ZO-1/Occludin/Claudin1) and restored the gut immune microenvironment in CP rabbits. In summary, supplementation with C. butyricum can alleviate the adverse effects of CP on growth performance and hepatic lipid synthesis by modulating the gut-liver axis.

Unveiling the complex relationship between gut microbiota and liver cancer: opportunities for novel therapeutic interventions

Hepatocellular carcinoma (HCC) has been linked to the gut microbiota, with recent studies revealing the potential of gut-generated responses to influence several arms of the immune responses relevant to HCC formation. The pro- or anti-tumor effects of specific bacterial strains or gut microbiota-related metabolites, such as bile acids and short-chain fatty acids, have been highlighted in many human and animal studies. The critical role of the gut microbiota in HCC development has spurred interest in modulating the gut microbiota through dietary interventions, probiotics, and fecal microbiota transplantation as a potential strategy to improve liver cancer outcomes. Encouragingly, preclinical and clinical studies have demonstrated that modulation of the gut microbiota can ameliorate liver function, reduce inflammation, and inhibit liver tumor growth, underscoring the potential of this approach to improve HCC outcomes. As research continues to unravel the complex and dynamic mechanisms underlying the gut-liver axis, the development of safe and effective interventions to target this pathway for liver cancer prevention and treatment appears to be on the horizon, heralding a significant advance in our ongoing efforts to combat this devastating disease.

Microbiota-Accessible Boron-Containing Compounds in Complex Regional Pain Syndrome

The microbiota-gut-brain axis has garnered increasing attention in recent years for its role in various health conditions, including neuroinflammatory disorders like complex regional pain syndrome (CRPS). CRPS is a debilitating condition characterized by chronic neuropathic pain, and its etiology and pathophysiology remain elusive. Emerging research suggests that alterations in the gut microbiota composition and function could play a significant role in CRPS development and progression. Our paper explores the implications of microbiota in CRPS and the potential therapeutic role of boron (B). Studies have demonstrated that individuals with CRPS often exhibit dysbiosis, with imbalances in beneficial and pathogenic gut bacteria. Dysbiosis can lead to increased gut permeability and systemic inflammation, contributing to the chronic pain experienced in CRPS. B, an essential trace element, has shown promise in modulating the gut microbiome positively and exerting anti-inflammatory effects. Recent preclinical and clinical studies suggest that B supplementation may alleviate neuropathic pain and improve CRPS symptoms by restoring microbiota balance and reducing inflammation. Our review highlights the complex interplay between microbiota, inflammation, and neuropathic pain in CRPS and underscores the potential of B as a novel therapeutic approach to target the microbiota-gut-brain axis, offering hope for improved management of this challenging condition.

Low Short-Chain-Fatty-Acid-Producing Activity of the Gut Microbiota Is Associated with Hypercholesterolemia and Liver Fibrosis in Patients with Metabolic-Associated (Non-Alcoholic) Fatty Liver Disease

The aim of this study was to investigate the short-chain fatty acid (SCFA) activity of the gut microbiota of patients with metabolic-associated fatty liver disease (MAFLD). The level and spectrum of short-chain fatty acids (SCFAs) were determined via gas–liquid chromatography. Liver fibrosis was assessed using the FIB-4 index and elastography. Among 42 non-cirrhotic MAFLD patients, 24 had high fecal SCFA levels (group H) and 18 had low fecal SCFA levels (group L). Patients in group H had lower serum uric acid, total cholesterol, and LDL cholesterol levels but a higher BMI than those in group L. All patients in group L and only 37.9% of those in group H were found to have hypercholesterolemia. In patients with hypercholesterolemia, the level of SCFAs was lower than that in patients without hypercholesterolemia. Patients in group H had less liver fibrosis than patients in group L. A total of 50.0% of the patients in group H and 92.3% of those in group L had significant liver fibrosis (≥F2). Patients with significant liver fibrosis had lower levels of fecal SCFAs—particularly acetate and butyrate. The fecal SCFA levels were positively correlated with gamma-glutamyl transferase, total bilirubin levels, BMI, and platelet count and were negatively correlated with FIB-4, liver stiffness, serum total, and LDL cholesterol levels.

Activation of the aryl hydrocarbon receptor in inflammatory bowel disease: insights from gut microbiota

Inflammatory bowel disease (IBD) is a chronic inflammatory intestinal disease that affects more than 3.5 million people, with rising prevalence. It deeply affects patients' daily life, increasing the burden on patients, families, and society. Presently, the etiology of IBD remains incompletely clarified, while emerging evidence has demonstrated that altered gut microbiota and decreased aryl hydrocarbon receptor (AHR) activity are closely associated with IBD. Furthermore, microbial metabolites are capable of AHR activation as AHR ligands, while the AHR, in turn, affects the microbiota through various pathways. In light of the complex connection among gut microbiota, the AHR, and IBD, it is urgent to review the latest research progress in this field. In this review, we describe the role of gut microbiota and AHR activation in IBD and discussed the crosstalk between gut microbiota and the AHR in the context of IBD. Taken as a whole, we propose new therapeutic strategies targeting the AHR-microbiota axis for IBD, even for other related diseases caused by AHR-microbiota dysbiosis.

The role of NADPH oxidase 1 in alcohol-induced oxidative stress injury of intestinal epithelial cells

Alcohol-mediated reactive oxygen species (ROS) play a vital role in intestinal barrier injury. However, the mechanism of ROS accumulation in enterocytes needs to be explored further. In our study, we found that chronic-binge ethanol-fed mice had increased levels of gut oxidative stress and high intestinal permeability. The transcription profiles of the colonic epithelial cells showed that the level of NADPH oxidase 1 (NOX1) was significantly elevated in alcohol-exposed mice compared with isocaloric-exposed mice. In vitro, NOX1 silencing alleviated ROS accumulation and the apoptosis of human colonic epithelial cells (NCM460), while NOX1 overexpression accelerated oxidative stress injury of NCM460 cells. Propionic acid was reduced in the gut of chronic-binge ethanol-fed mice, compared with isocaloric-fed mice, as observed through untargeted metabolomic analysis. Supplementation with propionate relieved ethanol-induced liver and intestinal barrier injuries and reduced the level of ROS accumulation and apoptosis of ethanol-induced colonic epithelial cells. Propionate alleviating NOX1 induced ROS injury of colonic epithelial cells, independent of G protein-coupled receptors. Propionate significantly inhibited histone deacetylase 2 (HDAC2) expressions both in ethanol-exposed colonic epithelial cells and TNF-α-treated NCM460. Chromatin immunoprecipitation (ChIP) assays showed that propionate suppressed the NOX1 expression by regulating histone acetylation in the gene promoter region. In conclusion, NOX1 induces oxidative stress injury of colonic epithelial cells in alcohol-related liver disease. Propionate, which can act as an endogenous HDAC2 inhibitor, can decrease levels of apoptosis of intestinal epithelial cells caused by oxidative stress.

Effects of Human Milk Fat Substitutes on Lipid Metabolism in First-Weaned Rats

Although numerous studies indicate that formula-fed infants are more prone to obesity than breastfed ones, the underlying reasons have not been fully elucidated. This study aimed to determine the impact of human milk fat substitutes (HMFS) on the lipid metabolism of first-weaned Sprague Dawley rats. The findings revealed that administering HMFS did not affect the body weight of the rats (control: 298.38 ± 26.73 g, OPO (1,3-dioleic acid-2-palmitoyl triglyceride): 287.82 ± 19.85 g and HMFS: 302.31 ± 19.21 g), but it significantly decreased their body fat content (control: 28.70 ± 1.17 cm3, OPO: 22.51 ± 1.10 cm3 and HMFS: 14.90 ± 0.95 cm3) (p < 0.05). Lipidome analysis revealed that glycerophospholipid was the primary differentiating lipid present in the liver of HMFS-fed rats. The abundance of Bacteroides significantly increased in the intestine of HMFS-fed rats (p < 0.05), and their short-chain fatty acid (SCFA) content significantly increased (p < 0.05). The multi-omics correlation analysis established the "Bacteroidetes-SCFAs-Glycerophospholipid pathway" as a potential mechanism by which administering HMFS affects body fat buildup in first-weaned rats. Additionally, it was found that HMFS administration significantly promoted lipid metabolism in the rat liver at both the gene and protein levels (p < 0.05). These findings serve to underscore the nutritional benefits of HMFS for infants.

Gut microbial metabolite butyrate improves anticancer therapy by regulating intracellular calcium homeostasis

BACKGROUND AND AIMS

Gut microbiota are recognized to be important for anticancer therapy, yet the underlying mechanism is not clear. Here, through the analysis of clinical samples, we identify the mechanism by which the gut microbial metabolite butyrate inhibits HCC and then explore new strategies for HCC treatment.

APPROACH AND RESULTS

In our study, we demonstrate that gut microbial metabolite butyrate improves anticancer therapy efficacy by regulating intracellular calcium homeostasis. Using liquid chromatography-mass spectrometry analysis, we found that butyrate metabolism is activated in HCC patients compared with healthy individuals. Butyrate levels are lower in the plasma of HCC patients by gas chromatography-mass spectrometry (GC-MS) analysis. Butyrate supplementation or depletion of short-chain Acyl-CoA dehydrogenase (SCAD) gene (ACADS), encoding a key enzyme for butyrate metabolism, significantly inhibits HCC proliferation and metastasis. The profiling analysis of genes upregulated by butyrate supplementation or ACADS knockdown reveals that calcium signaling pathway is activated, leading to dysregulation of intracellular calcium homeostasis and production of reactive oxygen species. Butyrate supplementation improves the therapy efficacy of a tyrosine kinase inhibitor sorafenib. On the basis of these findings, we developed butyrate and sorafenib coencapsulated mPEG-PLGA-PLL nanoparticles coated with anti-GPC3 antibody (BS@PEAL-GPC3) to prolong the retention time of drugs and enhance drug targeting, leading to high anticancer efficacy. BS@PEAL-GPC3 nanoparticles significantly reduce HCC progression. In addition, BS@PEAL-GPC3 nanoparticles display excellent HCC targeting with excellent safety.

CONCLUSIONS

In conclusion, our findings provide new insight into the mechanism by which the gut microbial metabolites inhibit HCC progression, suggesting a translatable therapeutics approach to enhance the clinical targeted therapeutic efficacy.

Molecular Ensembles of Microbiotic Metabolites in Carcinogenesis

The mechanisms of carcinogenesis are extremely complex and involve multiple components that contribute to the malignant cell transformation, tumor growth, and metastasis. In recent decades, there has been a growing interest in the role of symbiotic human microbiota in the regulation of metabolism and functioning of host immune system. The symbiosis between a macroorganism and its microbiota has given rise to the concept of a holoorganism. Interactions between the components of a holoorganism have formed in the process of coevolution, resulting in the acquisition by microbiotic metabolites of a special role of signaling molecules and main regulators of molecular interactions in the holoorganism. As elements of signaling pathways in the host organism, bacterial metabolites have become essential participants in various physiological and pathological processes, including tumor growth. At the same time, signaling metabolites often exhibit multiple effects and impact both the functions of the host cells and metabolic activity and composition of the microbiome. This review discusses the role of microbiotic metabolites in the induction and prevention of malignant transformation of cells in the host organism and their impact on the efficacy of anticancer therapy, with special emphasis on the involvement of some components of the microbial metabolite molecular ensemble in the initiation and progression of tumor growth.

A Comparative Study on the Effects of Different Sources of Carboxymethyl Poria Polysaccharides on the Repair of DSS-Induced Colitis in Mice

Carboxymethyl poria polysaccharide plays important anti-tumor, antioxidant, and anti-inflammatory roles. Therefore, this study aimed to compare the healing impacts of two different sources of carboxymethyl poria polysaccharides [Carboxymethylat Poria Polysaccharides I (CMP I) and Carboxymethylat Poria Polysaccharides II (CMP II)] on ulcerative colitis in mice caused by dextran sulfate sodium (DSS). All the mice were arbitrarily split into five groups (n = 6): (a) control (CTRL), (b) DSS, (c) SAZ (sulfasalazine), (d) CMP I, and (e) CMP II. The experiment lasted for 21 days, and the body weight and final colon length were monitored. A histological analysis of the mouse colon tissue was carried out using H&E staining to assess the degree of inflammatory infiltration. The levels of inflammatory cytokines [interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-4 (IL-4)] and enzymes [superoxide dismutase (SOD) and myeloperoxidase (MPO)] in the serum were examined using ELISA. Additionally, 16S ribosomal RNA sequencing was used to analyze the microorganisms in the colon. The results indicated that both CMP I and CMP II alleviated weight loss, colonic shortening, and inflammatory factor infestation in colonic tissues caused by DSS (p < 0.05). Furthermore, the ELISA results revealed that both CMP I and CMP II reduced the expression of IL-1β, IL-6, TNF-α, and MPO, and elevated the expression of IL-4 and SOD in the sera of the mice (p < 0.05). Moreover, 16S rRNA sequencing showed that CMP I and CMP II increased the plenitude of microorganisms in the mouse colon relative to that in the DSS group. The results also indicated that the therapeutic effect of CMP I on DSS-induced colitis in the mice was superior to that of CMP II. This study demonstrated that carboxymethyl poria polysaccharide from Poria cocos had therapeutic effects on DSS-induced colitis in mice, with CMP I being more effective than CMP II.

The Antioxidant Effect of Dietary Bioactives Arises from the Interplay between the Physiology of the Host and the Gut Microbiota: Involvement of Short-Chain Fatty Acids

The maintenance of redox homeostasis is associated with a healthy status while the disruption of this mechanism leads to the development of various pathological conditions. Bioactive molecules such as carbohydrates accessible to the microbiota (MACs), polyphenols, and polyunsaturated fatty acids (PUFAs) are food components best characterized for their beneficial effect on human health. In particular, increasing evidence suggests that their antioxidant ability is involved in the prevention of several human diseases. Some experimental data indicate that the activation of the nuclear factor 2-related erythroid 2 (Nrf2) pathway-the key mechanism in the maintenance of redox homeostasis-is involved in the beneficial effects exerted by the intake of PUFAs and polyphenols. However, it is known that the latter must be metabolized before becoming active and that the intestinal microbiota play a key role in the biotransformation of some ingested food components. In addition, recent studies, indicating the efficacy of the MACs, polyphenols, and PUFAs in increasing the microbial population with the ability to yield biologically active metabolites (e.g., polyphenol metabolites, short-chain fatty acids (SCFAs)), support the hypothesis that these factors are responsible for the antioxidant action on the physiology of the host. The underlying mechanisms through which MACs, polyphenols, and PUFAs might influence the redox status have not been fully elucidated, but based on the efficacy of SCFAs as Nrf2 activators, their contribution to the antioxidant efficacy of dietary bioactives cannot be excluded. In this review, we aimed to summarize the main mechanisms through which MACs, polyphenols, and PUFAs can modulate the host's redox homeostasis through their ability to directly or indirectly activate the Nrf2 pathway. We discuss their probiotic effects and the role played by the alteration of the metabolism/composition of the gut microbiota in the generation of potential Nrf2-ligands (e.g., SCFAs) in the host's redox homeostasis.

Targeting the aryl hydrocarbon receptor by gut phenolic metabolites: A strategy towards gut inflammation

The Aryl Hydrocarbon Receptor (AHR) is a ligand-dependent transcription factor able to control complex transcriptional processes in several cell types, which has been correlated with various diseases, including inflammatory bowel diseases (IBD). Numerous studies have described different compounds as ligands of this receptor, like xenobiotics, natural compounds, and several host-derived metabolites. Dietary (poly)phenols have been studied regarding their pleiotropic activities (e.g., neuroprotective and anti-inflammatory), but their AHR modulatory capabilities have also been considered. However, dietary (poly)phenols are submitted to extensive metabolism in the gut (e.g., gut microbiota). Thus, the resulting gut phenolic metabolites could be key players modulating AHR since they are the ones that reach the cells and may exert effects on the AHR throughout the gut and other organs. This review aims at a comprehensive search for the most abundant gut phenolic metabolites detected and quantified in humans to understand how many have been described as AHR modulators and what could be their impact on inflammatory gut processes. Even though several phenolic compounds have been studied regarding their anti-inflammatory capacities, only 1 gut phenolic metabolite, described as AHR modulator, has been evaluated on intestinal inflammatory models. Searching for AHR ligands could be a novel strategy against IBD.

Combing fecal microbial community data to identify consistent obesity-specific microbial signatures and shared metabolic pathways

Obesity is associated with altered gut microbiome composition but data across different populations remain inconsistent. We meta-analyzed publicly available 16S-rRNA sequence datasets from 18 different studies and identified differentially abundant taxa and functional pathways of the obese gut microbiome. Most differentially abundant genera (Odoribacter, Oscillospira, Akkermansia, Alistipes, and Bacteroides) were depleted in obesity, indicating a deficiency of commensal microbes in the obese gut microbiome. From microbiome functional pathways, elevated lipid biosynthesis and depleted carbohydrate and protein degradation suggested metabolic adaptation to high-fat, low-carbohydrate, and low-protein diets in obese individuals. Machine learning models trained on the 18 studies were modest in predicting obesity with a median AUC of 0.608 using 10-fold cross-validation. The median AUC increased to 0.771 when models were trained in eight studies designed for investigating obesity-microbiome association. By meta-analyzing obesity-associated microbiota signatures, we identified obesity-associated depleted taxa that may be exploited to mitigate obesity and related metabolic diseases.

Different Diet Energy Levels Alter Body Condition, Glucolipid Metabolism, Fecal Microbiota and Metabolites in Adult Beagle Dogs

Diet energy is a key component of pet food, but it is usually ignored during pet food development and pet owners also have limited knowledge of its importance. This study aimed to explore the effect of diet energy on the body condition, glucolipid metabolism, fecal microbiota and metabolites of adult beagles and analyze the relation between diet and host and gut microbiota. Eighteen healthy adult neutered male beagles were selected and randomly divided into three groups. Diets were formulated with three metabolizable energy (ME) levels: the low-energy (Le) group consumed a diet of 13.88 MJ/kg ME; the medium-energy (Me) group consumed a diet of 15.04 MJ/kg ME; and the high-energy (He) group consumed a diet of 17.05 MJ/kg ME. Moreover, the protein content of all these three diets was 29%. The experiment lasted 10 weeks, with a two-week acclimation period and an eight-week test phase. Body weight, body condition score (BCS), muscle condition score (MCS) and body fat index (BFI) decreased in the Le group, and the changes in these factors in the Le group were significantly higher than in the other groups (p < 0.05). The serum glucose and lipid levels of the Le and He groups changed over time (p < 0.05), but those of the Me group were stable (p > 0.05). The fecal pH of the Le and He groups decreased at the end of the trial (p < 0.05) and we found that the profiles of short-chain fatty acids (SCFAs) and bile acids (BAs) changed greatly, especially secondary BAs (p < 0.05). As SCFAs and secondary BAs are metabolites of the gut microbiota, the fecal microbiota was also measured. Fecal 16S rRNA gene sequencing found that the Me group had higher α-diversity indices (p < 0.05). The Me group had notably higher levels of gut probiotics, such as Faecalibacterium prausnitzii, Bacteroides plebeius and Blautia producta (p < 0.05). The diet-host-fecal microbiota interactions were determined by network analysis, and fecal metabolites may help to determine the best physical condition of dogs, assisting pet food development. Overall, feeding dogs low- or high-energy diets was harmful for glucostasis and promoted the relative abundance of pathogenic bacteria in the gut, while a medium-energy diet maintained an ideal body condition. We concluded that dogs that are fed a low-energy diet for an extended period may become lean and lose muscle mass, but diets with low energy levels and 29% protein may not supply enough protein for dogs losing weight.

Metabolomic Signatures of Scarff-Bloom-Richardson (SBR) Grade in Non-Metastatic Breast Cancer

PURPOSE

Identification of metabolomic biomarkers of high SBR grade in non-metastatic breast cancer.

METHODS

This retrospective bicentric metabolomic analysis included a training set (n = 51) and a validation set (n = 49) of breast cancer tumors, all classified as high-grade (grade III) or low-grade (grade I-II). Metabolomes of tissue samples were studied by liquid chromatography coupled with mass spectrometry.

RESULTS

A molecular signature of the top 12 metabolites was identified from a database of 602 frequently predicted metabolites. Partial least squares discriminant analyses showed that accuracies were 0.81 and 0.82, the R2 scores were 0.57 and 0.55, and the Q2 scores were 0.44431 and 0.40147 for the training set and validation set, respectively; areas under the curve for the Receiver Operating Characteristic Curve were 0.882 and 0.886. The most relevant metabolite was diacetylspermine. Metabolite set enrichment analyses and metabolic pathway analyses highlighted the tryptophan metabolism pathway, but the concentration of individual metabolites varied between tumor samples.

CONCLUSIONS

This study indicates that high-grade invasive tumors are related to diacetylspermine and tryptophan metabolism, both involved in the inhibition of the immune response. Targeting these pathways could restore anti-tumor immunity and have a synergistic effect with immunotherapy. Recent studies could not demonstrate the effectiveness of this strategy, but the use of theragnostic metabolomic signatures should allow better selection of patients.

Microbiome-liver crosstalk: A multihit therapeutic target for liver disease

Liver disease has become a leading cause of death, particularly in the West, where it is attributed to more than two million deaths annually. The correlation between gut microbiota and liver disease is still not fully understood. However, it is well known that gut dysbiosis accompanied by a leaky gut causes an increase in lipopolysaccharides in circulation, which in turn evoke massive hepatic inflammation promoting liver cirrhosis. Microbial dysbiosis also leads to poor bile acid metabolism and low short-chain fatty acids, all of which exacerbate the inflammatory response of liver cells. Gut microbial homeostasis is maintained through intricate processes that ensure that commensal microbes adapt to the low oxygen potential of the gut and that they rapidly occupy all the intestinal niches, thus outcompeting any potential pathogens for available nutrients. The crosstalk between the gut microbiota and its metabolites also guarantee an intact gut barrier. These processes that protect against destabilization of gut microbes by potential entry of pathogenic bacteria are collectively called colonization resistance and are equally essential for liver health. In this review, we shall investigate how the mechanisms of colonization resistance influence the liver in health and disease and the microbial-liver crosstalk potential as therapeutic target areas.

The Impact of Gut Microbiota-Derived Metabolites on the Tumor Immune Microenvironment

Prevention of the effectiveness of anti-tumor immune responses is one of the canonical cancer hallmarks. The competition for crucial nutrients within the tumor microenvironment (TME) between cancer cells and immune cells creates a complex interplay characterized by metabolic deprivation. Extensive efforts have recently been made to understand better the dynamic interactions between cancer cells and surrounding immune cells. Paradoxically, both cancer cells and activated T cells are metabolically dependent on glycolysis, even in the presence of oxygen, a metabolic process known as the Warburg effect. The intestinal microbial community delivers various types of small molecules that can potentially augment the functional capabilities of the host immune system. Currently, several studies are trying to explore the complex functional relationship between the metabolites secreted by the human microbiome and anti-tumor immunity. Recently, it has been shown that a diverse array of commensal bacteria synthetizes bioactive molecules that enhance the efficacy of cancer immunotherapy, including immune checkpoint inhibitor (ICI) treatment and adoptive cell therapy with chimeric antigen receptor (CAR) T cells. In this review, we highlight the importance of commensal bacteria, particularly of the gut microbiota-derived metabolites that are capable of shaping metabolic, transcriptional and epigenetic processes within the TME in a therapeutically meaningful way.

Nutrition and Microbiome Interactions in Human Cancer

Individual physiologic responses to changes in dietary patterns can vary widely to affect cancer risk, which is driven by multiple host-specific factors (eg, genetics, epigenetics, inflammatory and metabolic states, and the colonizing microbiome). Emerging evidence indicates that diet-induced microbiota alterations are key modulators of several host functions important to tumor etiology, progression, and response to cancer therapy. Thus, diet may potentially be used to target alterations of the microbiota as an effective means to improve outcomes across the cancer continuum (from cancer prevention to tumor development and progression, to effects on treatment and survivorship). This review will focus on recent examples of functional interactions between dietary components (nutrients and non-nutrients) and the gastrointestinal microbiome, which are 2 critical and malleable environmental variables in cancer risk that affect host immune, metabolic, and cell signaling functions and may provide insights for novel cancer therapeutic and preventive strategies.

Irradiation-Induced Intestinal Injury is Associated With Disorders of Bile Acids Metabolism

PURPOSE

Intestinal injury commonly occurs in radiation therapy, but its pathogenesis is not well understood. The relationship between irradiation-induced intestinal injury and bile acids (BAs) metabolism remains elusive. This study intends to clarify the role of BAs metabolism in irradiation-induced intestinal injury and the potential for supplementation with BAs to alleviate this injury.

MATERIALS AND METHODS

BAs metabolomic analysis of fecal pellets from normal and 12 Gy γ-ray total abdominal irradiation (TAI) treated mice was performed. The effects of a crude bile extract (BAmix) or lithocholic acid (LCA) on mice exposed to 12 Gy γ-ray TAI were determined by analyzing weight loss, colon length, villus length, crypt number, and the expression of leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) and yes-associated protein 1 (YAP1). The effects of BAmix or LCA on intestinal organoids after 4 Gy irradiation were analyzed. ELISA assay was applied to test IL-1β, IL-6 and TNF-α levels in mouse intestine. The expression changes of G protein-coupled receptor 1 (TGR5) and YAP1 in the colonic mucosa of patients with radiation-induced intestinal injury were determined by IHC.

RESULTS

The relative abundance of secondary BAs was decreased while the relative abundance of primary BAs was increased in irradiated mice, and LCA was the most obvious change. BAmix and LCA alleviated irradiation-induced intestinal injury in a mouse model, as reflected by reduced body weight loss, longer colon, higher villus, more crypts, and increased Lgr5 expression. In intestinal organoids, BAmix and LCA enhanced newborn crypts formation after irradiation. LCA treatment improved the expression of TGR5 and YAP1 in mouse intestinal crypts. LCA has potential to reduce the inflammation levels in irradiated mice. Additionally, the expression levels of TGR5 and YAP1 in the colonic mucosa of patients with radiation enteritis were also significantly decreased.

CONCLUSIONS

Radiation-induced intestinal injury is associated with disorders of BAs metabolism, and treatment with LCA had a protective effect against radiation-induced intestinal injury in mice by modulating TGR5 and YAP1.

Swainsonine Induces Liver Inflammation in Mice via Disturbance of Gut Microbiota and Bile Acid Metabolism

Swainsonine induced liver inflammation in livestock; however, the underlying mechanisms, especially the role of bile acids (BAs), in the pathogenesis remained elusive. Here, our results showed that swainsonine induced hepatic inflammation via changing BA metabolism and gut microbiota in mice. Swainsonine significantly upregulated the levels of deoxycholic acid (DCA) and taurine-β-muricholic acid (T-β-MCA) in the serum and liver of mice due to the markedly increased genus Clostridium and the decreased genus Lactobacillus in the gut. As antagonists of the farnesoid X receptor (FXR), elevated DCA and T-β-MCA inhibited hepatic Fxr gene expression and thus suppressed FXR-SHP signaling and activated hepatic Cyp7a1 gene expression, which induced a significant upregulation of the total BA level in serum, contributing to liver inflammation. These findings offer new insights into the underlying mechanisms in which swainsonine induced liver inflammation in mice via the gut-liver axis and suggest that gut microbiota and its metabolite BAs may be underlying triggering factors.

Pulsatilla decoction improves DSS-induced colitis via modulation of fecal-bacteria-related short-chain fatty acids and intestinal barrier integrity

ETHNOPHARMACOLOGICAL RELEVANCE

Pulsatilla decoction (PD), is an herbal formula commonly used for the treatment of ulcerative colitis (UC) in clinical practice, but the mechanism of PD alters the colitis remains elusive.

AIM OF THE STUDY

To evaluate the intervention effect of PD on Dextran Sodium Sulfate (DSS)-induced UC based on gut microbiota and intestinal short-chain fatty acid (SCFAs) metabolism, and to investigate the mechanism of action of PD in treating UC.

MATERIALS AND METHODS

A 3% (wt/vol) DSS-induced ulcerative colitis model in C57BL/6 male mice was used to evaluate the effect of oral PD in treating UC. The changes in gut microbiota in mice were analyzed by 16SrDNA gene sequencing, and the content of SCFAs in the intestinal contents of mice was determined by gas chromatography-mass spectrometry (GC-MS). Enzyme-linked immunosorbent assay (ELISA) was applied to analyze the expression of inflammatory cytokines in serum and colonic tissues, and western blotting (WB) was applied to analyze the expression of tight junction proteins in colonic tissues.

RESULTS

PD can alleviate the symptoms of UC mice, Pulsatilla Decoction high dose treatment group (PDHT) shows the best effect. Compared with the DSS group, the PDHT had significantly lower body mass, disease activity index (DAI) score, colonic macroscopic damage index (CMDI) score, and pathological damage score, at the phylum level, the relative abundance of Bacteroidetes increased while that of Firmicutes and Proteobacteria decreased, at the Genus level, the abundance of Bacteroides and Lachnospiraceae.NK4A136.group increased while that of Clostridium. sensu.stricto。, Escherichia. shigella and Turicibacter decreased. Compared with the DSS group, acetate, propionate, and total SCFAs in the PDHT with significantly higher levels. The concentrations of interleukin-1β (L-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-17 (IL-17) decreased whereby the concentration of interleukin-10 (IL-10) increased in the PDHT group. The expression levels of Occludin, zonula occludens-1 (ZO-1), Claudin1, Claudin5, G protein-coupled receptor43 (GPR43) protein, and the relative expression of ZO-1 and Occludin mRNA were significantly increased PDHT group.

CONCLUSIONS

PD has a good therapeutic effect on UC mice. The pharmacological mechanism is probably maintaining the homeostasis and diversity of gut microbiota, increasing the content of SCFAs, and repairing the colonic mucosal barrier.

Maternal obesity and resistance to breast cancer treatments among offspring: Link to gut dysbiosis

BACKGROUND

About 50 000 new cases of cancer in the United States are attributed to obesity. The adverse effects of obesity on breast cancer may be most profound when affecting the early development; that is, in the womb of a pregnant obese mother. Maternal obesity has several long-lasting adverse health effects on the offspring, including increasing offspring's breast cancer risk and mortality. Gut microbiota is a player in obesity as well as may impact breast carcinogenesis. Gut microbiota is established early in life and the microbial composition of an infant's gut becomes permanently dysregulated because of maternal obesity. Metabolites from the microbiota, especially short chain fatty acids (SCFAs), play a critical role in mediating the effect of gut bacteria on multiple biological functions, such as immune system, including tumor immune responses.

RECENT FINDINGS

Maternal obesity can pre-program daughter's breast cancer to be more aggressive, less responsive to treatments and consequently more likely to cause breast cancer related death. Maternal obesity may also induce poor response to immune checkpoint inhibitor (ICB) therapy through increased abundance of inflammation associated microbiome and decreased abundance of bacteria that are linked to production of SCFAs. Dietary interventions that increase the abundance of bacteria producing SCFAs potentially reverses offspring's resistance to breast cancer therapy.

CONCLUSION

Since immunotherapies have emerged as highly effective treatments for many cancers, albeit there is an urgent need to enlarge the patient population who will be responsive to these treatments. One of the factors which may cause ICB refractoriness could be maternal obesity, based on its effects on the microbiota markers of ICB therapy response among the offspring. Since about 40% of children are born to obese mothers in the Western societies, it is important to determine if maternal obesity impairs offspring's response to cancer immunotherapies.

Regulation of viable/inactivated/lysed probiotic Lactobacillus plantarum H6 on intestinal microbiota and metabolites in hypercholesterolemic mice

Evidence suggests that probiotic interventions reduce non-communicable diseases (NCDs) risk. However, its therapeutic effect and mechanism are still unclear. To evaluate the hypocholesterolemic effect of Lactobacillus plantarum H6 (L.p H6), a new commercial patent strain capable of preventing hypercholesterolemia, and its mechanism in depth, three states of the strain were prepared, namely, viable (vH6), heat-inactivated (iH6), and ultrasonically-lysed (uH6) bacteria cells. The results showed that v/i/uH6 cells could lower serum and liver blood lipid levels, alleviate liver damage and improve glucose tolerance test (GTT) and insulin tolerance test (ITT) indexes. v/i/uH6 cells improved the gut microbial composition and significantly reduced the Firmicutes to Bacteroidetes ratio (F/B ratio) in feces. In particular, Muribaculaceae may be a potential biomarker for effective cholesterol reduction. Also, the recovery of these biochemical indices and gut microbiome was found following fecal microbiota transplantation (FMT) using stool from vH6 treated mice. The v/i/uH6 cells increased the intestinal flora metabolism of vitamins-cofactors, as well as amino acids, while decreasing the relative content of primary bile acids. The Pearson correlation analysis showed that norank_f__Muribaculaceae and Lactobacillus had a negative correlation with blood lipid levels. Overall, v/i/uH6 cells were effective in improving hypercholesterolemia in mice, and this effect was attributed partly to the regulation of intestinal microbiota and metabolites related to lipid metabolism. Our findings provided a theoretical basis for the industrial development of probiotics and postbiotics and the treatment of cholesterol diseases.

Effects of long-term simulated microgravity on liver metabolism in rhesus macaques

The liver is an essential multifunctional organ and constantly communicates with nearly all the tissues in the body. Spaceflight or simulated microgravity has a significant impact on the livers of rodent models, including lipid accumulation and inflammatory cell infiltration. Whether similar liver lipotoxicity could occur in humans is not known, even though altered circulating cholesterol profile has been reported in astronauts. Using a 42-day head-down bed rest (HDBR) model in rhesus macaques, the present study investigated whether simulated microgravity alters the liver of non-human primates at the transcriptome and metabolome levels. Its association with stress and intestinal changes was also explored. Compared to the controls, the HDBR monkeys showed mild liver injury, elevated ANGPTL3 level in the plasma, and accumulation of fat vacuoles and inflammatory cells in the liver. Altered transcriptome signatures with up-regulation of genes in lipid metabolisms and down-regulation of genes in innate immune defense were also found in HDBR group-derived liver samples. The metabolic profiling of the liver revealed mildly disturbed fatty acid metabolism in the liver of HDBR monkeys. The intestinal dysbiosis, its associated endotoxemia and changes in the composition of bile acids, and elevated stress hormone in HDBR monkeys may contribute to the altered lipid metabolisms in the liver. These data indicate that liver metabolic functions and gut-liver axis should be closely monitored in prolonged spaceflight to facilitate strategy design to improve and maintain metabolic homeostasis.

A systematic review on omics data (metagenomics, metatranscriptomics, and metabolomics) in the role of microbiome in gallbladder disease

Microbiotas are the range of microorganisms (mainly bacteria and fungi) colonizing multicellular, macroscopic organisms. They are crucial for several metabolic functions affecting the health of the host. However, difficulties hamper the investigation of microbiota composition in cultivating microorganisms in standard growth media. For this reason, our knowledge of microbiota can benefit from the analysis of microbial macromolecules (DNA, transcripts, proteins, or by-products) present in various samples collected from the host. Various omics technologies are used to obtain different data. Metagenomics provides a taxonomical profile of the sample. It can also be used to obtain potential functional information. At the same time, metatranscriptomics can characterize members of a microbiome responsible for specific functions and elucidate genes that drive the microbiotas relationship with its host. Thus, while microbiota refers to microorganisms living in a determined environment (taxonomy of microorganisms identified), microbiome refers to the microorganisms and their genes living in a determined environment and, of course, metagenomics focuses on the genes and collective functions of identified microorganisms. Metabolomics completes this framework by determining the metabolite fluxes and the products released into the environment. The gallbladder is a sac localized under the liver in the human body and is difficult to access for bile and tissue sampling. It concentrates the bile produced in the hepatocytes, which drains into bile canaliculi. Bile promotes fat digestion and is released from the gallbladder into the upper small intestine in response to food. Considered sterile originally, recent data indicate that bile microbiota is associated with the biliary tract’s inflammation and carcinogenesis. The sample size is relevant for omic studies of rare diseases, such as gallbladder carcinoma. Although in its infancy, the study of the biliary microbiota has begun taking advantage of several omics strategies, mainly based on metagenomics, metabolomics, and mouse models. Here, we show that omics analyses from the literature may provide a more comprehensive image of the biliary microbiota. We review studies performed in this environmental niche and focus on network-based approaches for integrative studies.

Presume Why Probiotics May Not Provide Protection in Inflammatory Bowel Disease through an Azoxymethane and Dextran Sodium Sulfate Murine Model

Recent studies have shown dysbiosis is associated with inflammatory bowel disease (IBD). However, trying to restore microbial diversity via fecal microbiota transplantation (FMT) or probiotic intervention fails to achieve clinical benefit in IBD patients. We performed a probiotic intervention on a simulated IBD murine model to clarify their relationship. IBD was simulated by the protocol of azoxymethane and dextran sodium sulfate (AOM/DSS) to set up a colitis and colitis-associated neoplasm model on BALB/c mice. A single probiotic intervention using Clostridium butyricum Miyairi (CBM) on AOM/DSS mice to clarify the role of probiotic in colitis, colitis-associated neoplasm, gut microbiota, and immune cytokines was performed. We found dysbiosis occurred in AOM/DSS mice. The CBM intervention on AOM/DSS mice failed to improve colitis and colitis-associated neoplasms but changed microbial composition and unexpectedly increased expression of proinflammatory IL-17A in rectal tissue. We hypothesized that the probiotic intervention caused dysbiosis. To clarify the result, we performed inverse FMT using feces from AOM/DSS mice to normal recipients to validate the pathogenic effect of dysbiosis from AOM/DSS mice and found mice on inverse FMT did develop colitis and colon neoplasms. We presumed the probiotic intervention to some extent caused dysbiosis as inverse FMT. The role of probiotics in IBD requires further elucidation.

Fine-tuning of regulatory T cells is indispensable for the metabolic steatosis-related hepatocellular carcinoma: A review

The majority of chronic hepatic diseases are caused by nutritional imbalance. These nutritional inequities include excessive intake of alcohol and fat, which causes alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD), respectively. The pathogenesis of hepatic diseases is mainly dependent on oxidative stress, autophagy, DNA damage, and gut microbiota and their metabolites. These factors influence the normal physiology of the liver and impact the hepatic microenvironment. The hepatic microenvironment contains several immune cells and inflammatory cytokines which interact with each other and contribute to the progression of chronic hepatic diseases. Among these immune cells, Foxp3⁺ CD4⁺ regulatory T cells (Tregs) are the crucial subset of CD4⁺ T cells that create an immunosuppressive environment. This review emphasizes the function of Tregs in the pathogenesis of ALD and NAFLD and their role in the progression of NAFLD-associated hepatocellular carcinoma (HCC). Briefly, Tregs establish an immunosuppressive landscape in the liver by interacting with the innate immune cells and gut microbiota and their metabolites. Meanwhile, with the advancement of steatosis, these Tregs inhibit the proliferation, activation and functions of other cytotoxic T cells and support the progression of simple steatosis to HCC. Briefly, it can be suggested that targeting Tregs can act as a favourable prognostic indicator by modulating steatosis and insulin resistance during the pathogenesis of hepatic steatosis and NAFLD-associated HCC.

Metabolomics of Breast Cancer: A Review

Breast cancer is the most commonly diagnosed cancer in women worldwide. Major advances have been made towards breast cancer prevention and treatment. Unfortunately, the incidence of breast cancer is still increasing globally. Metabolomics is the field of science which studies all the metabolites in a cell, tissue, system, or organism. Metabolomics can provide information on dynamic changes occurring during cancer development and progression. The metabolites identified using cutting-edge metabolomics techniques will result in the identification of biomarkers for the early detection, diagnosis, and treatment of cancers. This review briefly introduces the metabolic changes in cancer with particular focus on breast cancer.

Amelioratory Effect of Resistant Starch on Non-alcoholic Fatty Liver Disease via the Gut-Liver Axis

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome with a global prevalence. Impaired gut barrier function caused by an unhealthy diet plays a key role in disrupting the immune-metabolic homeostasis of the gut-liver axis (GLA), leading to NAFLD. Therefore, dietary interventions have been studied as feasible alternative therapeutic approaches to ameliorate NAFLD. Resistant starches (RSs) are prebiotics that reduce systemic inflammation in patients with metabolic syndrome. The present review aimed to elucidate the mechanisms of the GLA in alleviating NAFLD and provide insights into how dietary RSs counteract diet-induced inflammation in the GLA. Emerging evidence suggests that RS intake alters gut microbiota structure, enhances mucosal immune tolerance, and promotes the production of microbial metabolites such as short-chain fatty acids (SCFAs) and secondary bile acids. These metabolites directly stimulate the growth of intestinal epithelial cells and elicit GPR41/GPR43, FXR, and TGR5 signaling cascades to sustain immune-metabolic homeostasis in the GLA. The literature also revealed the dietary-immune-metabolic interplay by which RSs exert their regulatory effect on the immune-metabolic crosstalk of the GLA and the related molecular basis, suggesting that dietary intervention with RSs may be a promising alternative therapeutic strategy against diet-induced dysfunction of the GLA and, ultimately, the risk of developing NAFLD.

Regulatory role of short-chain fatty acids in inflammatory bowel disease

Inflammatory bowel disease (IBD) comprises a group of chronic inflammatory disorders of the gastrointestinal tract. Accumulating evidence shows that the development of IBD is always accompanied by the dysbiosis of the gut microbiota (GM), causing a decrease in prebiotic levels and an increase in harmful metabolite levels. This leads to persistent immune response and inflammation in the intestine, greatly impairing the physiological function of the gastrointestinal tract. Short-chain fatty acids (SCFAs) are produced by probiotic gut bacteria from a fiber-rich diet that cannot be digested directly. SCFAs with significant anti-inflammatory functions regulate immune function and prevent an excessive immune response, thereby delaying the clinical progression of IBD. In this review, we summarize the generation of SCFAs and their potential therapeutic effects on IBD. Furthermore, we suggest that SCFAs may modulate innate immune recognition and cytokine production to intervene in the progression of IBD. Additional randomized controlled trials and prospective cohort studies should also investigate the clinical impact of SCFA. Video Abstract.

Anti-Inflammatory Dietary Approach to Prevent the Development and Progression of Non-Alcoholic Fatty Liver Diseases

Non-alcoholic fatty liver disease (NAFLD) is an increasing health problem worldwide and is associated with insulin resistance, increased visceral fat mass, and cardiovascular problems. Lifestyle factors such as sedentary lifestyle, chronic stress, obesogenic environment as well as a Western pattern diet are main contributors to the development and progression of this disease. In particular, the diet plays a pivotal role. An unhealthy diet including high consumption of red and processed meats, refined carbohydrates, simple sugars, highly processed foods with food additives and conservatives are lighting the fire for a low-grade inflammation. If other risk factors come into play, metabolic and hormonal derangement may occur, leading to the increase in visceral fat, gut dysbiosis and leaky gut, which stoke the inflammatory fire. Thus, lifestyle interventions are the most effective approach to quell the inflammatory processes. An anti-inflammatory and low-glycemic diet named the GLykLich diet, which includes whole and unprocessed foods, may reduce the risk of increased morbidity and mortality. The GLykLich diet suggests a meal consisting of complex carbohydrates (fiber), good quality of protein and healthy fats (DHA/EPA), and is rich in secondary plant products. There is no single nutrient to prevent the progression of NAFLD, rather, it is the complexity of substances in whole unprocessed foods that reduce the inflammatory process, improve metabolic state, and thus reverse NAFLD.