A mechanism by which gut microbiota elevates permeability and inflammation in obese/diabetic mice and human gut

Mucus-penetrating microbiota drive chronic low-grade intestinal inflammation and metabolic dysregulation

Metabolic syndrome is, in humans, associated with alterations in the composition and localization of the intestinal microbiota, including encroachment of bacteria within the colon's inner mucus layer. Possible promoters of these events include dietary emulsifiers, such as carboxymethylcellulose (CMC) and polysorbate-80 (P80), which, in mice, result in altered microbiota composition, encroachment, low-grade inflammation and metabolic syndrome. While assessments of gut microbiota composition have largely focused on fecal/luminal samples, we hypothesize an outsized role for changes in mucus microbiota in driving low-grade inflammation and its consequences. In support of this notion, we herein report that both CMC and P80 led to stark changes in the mucus microbiome, markedly distinct from those observed in feces. Moreover, transfer of mucus microbiota from CMC- and P80-fed mice to germfree mice resulted in microbiota encroachment, low-grade inflammation, and various features of metabolic syndrome. Thus, we conclude that mucus-associated bacteria are pivotal determinants of intestinal inflammatory tone and host metabolism.

Renshen Zhuye decoction ameliorates high-fat diet-induced obesity and insulin resistance by modulating gut microbiota and metabolic homeostasis

BACKGROUND

Obesity, characterized by excessive adipose tissue accumulation, has become a global health challenge with rapidly increasing prevalence. It contributes significantly to metabolic disorders including insulin resistance (IR). Renshen-zhuye decoction (RZD), a traditional Chinese medicine formula historically used for diabetes, shows potential for improving metabolic parameters, but its effects and mechanisms in obesity and insulin resistance remain unclear.

PURPOSE

This study aimed to evaluate the therapeutic benefits of RZD on obesity and insulin resistance, and to elucidate the underlying mechanisms through which it improves glucose and lipid metabolism.

METHODS

The role of RZD was evaluated in a high-fat diet (HFD) mouse model. The formula was characterized using UPLC-MS. Comprehensive analyses including histopathological staining, immunofluorescence, biochemical assays, 16S rRNA gene sequencing of gut microbiota, and non-targeted metabolomic analysis were performed. To validate the role of gut microbiota, we employed antibiotic treatment (ABX) to deplete intestinal flora and conducted fecal microbiota transplantation (FMT) experiments.

RESULTS

RZD treatment dose-dependently alleviated HFD-induced dyslipidemia and insulin resistance, improving glucose tolerance, insulin sensitivity, and energy expenditure. Gut microbiota analysis revealed that RZD significantly modulated the composition of intestinal flora and their metabolic profiles. Additionally, RZD reduced intestinal and systemic inflammation by enhancing intestinal barrier integrity, particularly through increased expression of tight junction proteins such as Occludin. Importantly, the beneficial effects of RZD on weight management and glucose homeostasis were antagonized by antibiotic intervention, while FMT experiments confirmed that these improvements were mediated through gut microbiota modulation.

CONCLUSION

This study provides new insights into RZD's modulatory effects on gut microbiota and subsequent improvements in obesity-related metabolic parameters. RZD alleviates HFD-induced obesity and insulin resistance in mice by modulating gut microbiota composition and function, which subsequently improves intestinal barrier integrity, reduces inflammation, and enhances metabolic homeostasis.

Reshaping the gut microbiota: Tangliping decoction and its core blood-absorbed component quercetin improve diabetic cognitive impairment

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of cognitive decline, which can result in diabetic cognitive impairment (DCI). Recent studies have indicated that gut microbiota plays a significant role in the development of DCI. Tangliping Decoction (TLP), a traditional Chinese medicine compound, contains various active ingredients that have been shown to regulate the microecology of gut microbiota and potentially improve DCI. However, it remains unclear whether TLP can improve DCI by modulating gut microbiota, as well as which specific component is primarily responsible for these effects.

PURPOSE

Assess the impact of TLP on alleviating DCI and investigate the contribution of quercetin (QR), the core blood-absorbed component of TLP, in this process. and investigate the underlying mechanisms through which TLP and QR enhance DCI by modulating gut microbiota composition.

STUDY DESIGN AND METHODS

Initially, experiments such as morris water maze (MWM), morphological analysis, and 16S ribosomal RNA (16S rRNA) gene amplicon sequencing from DCI mice, were performed to validate the pharmacological efficacy of TLP in mitigating DCI. The results indicated that TLP possesses the capacity to modulate the composition and quantity of gut microbiota and safeguard the integrity of the gut barrier and brain barrier. Secondly, high performance liquid chromatography coupled with high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS/MS) combined with network pharmacology methods were used to screen for blood-absorbed components, suggesting that QR may be a potential core blood-absorbed component of TLP in the treatment of DCI. Subsequently, the pharmacological efficacy of QR in ameliorating DCI was confirmed, and the characteristics of gut microbiota as well as the permeability of the gut and brain barrier, were assessed. Finally, fecal microbiota transplantation (FMT) experiments were conducted, wherein fecal matter from TLP and QR-treated mice (donor mice) was transplanted into pseudo-sterile DCI mice with antibiotic-induced depletion of gut microbiota. This approach aimed to elucidate the specific mechanisms by which TLP and QR improve DCI through the modulation of the structure, composition, and abundance of gut microbiota.

RESULTS

TLP and QR have the potential to enhance learning and memory capabilities in DCI mice, as well as reduce homeostasis model assessment insulin resistance (HOMA-IR) and restore homeostasis model assessment-β function (HOMA- β), leading to increased fasting insulin (FIN) levels and decreased fasting blood glucose (FBG) levels. Simultaneously, the administration of FMT from donor mice to pseudo-sterile DCI mice has been shown to alter the composition and abundance of gut microbiota, leading to amelioration of pathological damage in the colon and hippocampal tissues. Ultimately, FMT utilizing fecal suspensions from donor mice treated with TLP and QR improved cognitive function in pseudo-sterile DCI mice, restore gut microbiota dysbiosis, and maintained the integrity of the gut and brain barriers.

CONCLUSION

The results of this study indicate that TLP and its core component, QR, which is absorbed into the bloodstream, improve DCI through a gut microbiota-dependent mechanism, providing further evidence for gut microbiota as a therapeutic target for DCI treatment.

Gut microbiome links obesity to type 2 diabetes: insights from Mendelian randomization

BACKGROUND

Research has established links between the gut microbiome (GM) and both obesity and type 2 diabetes (T2D), which is much discussed, but underexplored. This study employed body mass index (BMI) as the measurement of obesity to delve deeper into the correlations from a genetic perspective.

METHODS

We performed the Mendelian randomization (MR) analysis to examine the causal effects of GM on T2D and BMI, and vice versa. Genome-wide association study (GWAS) summary datasets were utilized for the analysis, including T2D (N = 933,970), BMI (N = 806,834), and two GM datasets from the international consortium MiBioGen (211 taxa, N = 18,340) and the Dutch Microbiome Project (DMP) (207 taxa, N = 7,738). These datasets mainly cover European populations, with additional cohorts from Asia and other regions. To further explore the potential mediating role of GM in the connections between BMI and T2D, their interaction patterns were summarized into a network.

RESULTS

MR analysis identified 9 taxa that showed protective properties against T2D. Seven species were within the Firmicutes and Bacteroidales phyla in the DMP, and two were from the MiBioGen (Odds Ratio (OR): 0.94-0.95). Conversely, genetic components contributing to the abundance of 12 taxa were associated with increased risks of T2D (OR: 1.04-1.12). Furthermore, T2D may elevate the abundance of seven taxa (OR: 1.03-1.08) and reduce the abundance of six taxa (OR: 0.93-0.97). In the analysis of the influence of the genetic component of BMI on GM composition, BMI affected 52 bacterial taxa, with 28 decreasing (OR: 0.75-0.92) and 24 increasing (OR: 1.08-1.27). Besides, abundances of 25 taxa were negatively correlated with BMI (OR: 0.95-0.99), while positive correlations were detected for 14 taxa (OR: 1.01-1.05). Notably, we uncovered 11 taxa genetically associated with both BMI and T2D, which formed an interactive network.

CONCLUSIONS

Our findings provide evidence for the GM-mediated links between obesity and T2D. The identification of relevant GM taxa offers valuable insights into the potential role of the microbiome in these diseases.

Interruptins Extracted from Cyclosorus terminans Protect Gut Pathologies Induced by High-Fat Diet in Rats

BACKGROUND/OBJECTIVES

The fern "Cyclosorus terminans" (C. terminans) or "Maiden Fern" contains interruptin A and interruptin B. This plant could attenuate obesity, insulin resistance, and fatty liver in rats fed a high-fat/calorie diet. However, the benefits of C. terminans to the gut remain unknown. We investigated the protective effect of C. terminans extract against gut dysfunction in rats exposed to a high-fat/calorie diet.

METHODS

Male Wistar rats were assigned to receive either (1) a normal diet treated with vehicle, (2) a high-fat/calorie diet treated with vehicle, (3) a high-fat/calorie diet treated with 100 mg per kg per day (mg·kg-1·day-1) of C. terminans extract, or (4) a high-fat/calorie diet treated with 200 mg·kg-1·day-1 of C. terminans extract. The rats were euthanized after 12 weeks of treatment to enable feces and colon tissue collection.

RESULTS

Both 100 and 200 mg·kg-1·day-1 of C. terminans extract reduced body weight (-10.49%; p = 0.030 and -10.54%; p = 0.037, respectively) and ameliorated gut inflammation, gut barrier disruption, changes in short-chain fatty acid levels, and gut dysbiosis caused by high-fat/calorie diet.

CONCLUSIONS

C. terminans extract attenuated an increase in body weight and exerted prophylactic effects against gut pathologies induced by high-fat/calorie diet.

Oral exposure to nanoplastics and food allergy in mice fed a normal or high-fat diet

The global prevalence of food allergies, particularly IgE-mediated responses, is increasing at an alarming rate. This trend is likely driven by environmental factors such as nanoplastics (NPs) ingestion and the westernization of dietary and lifestyle habits. This study examines the impact of polystyrene nanoplastics (PS-NPs) on ovalbumin (OVA)-induced food allergies in mice subjected to either a normal diet (ND) or a high-fat diet (HFD). BALB/c mice were stratified into eight groups based on dietary regimen, NP exposure, and OVA sensitization. Food allergy was induced via OVA administration, and multiple physiological and immunological parameters were evaluated, including body weight, intestinal permeability, cytokine profiles, gut microbiota composition, and small intestinal gene expression. Mice in the HFD + OVA + NP group exhibited significant increases in intestinal permeability, diarrhea severity, and serum OVA-specific IgE levels compared to other groups. Flow cytometric analysis revealed an expansion of innate lymphoid cells (ILC2 and ILC1) within the lamina propria of the small intestine. Shotgun metagenomic sequencing demonstrated gut microbiota dysbiosis, characterized by a reduction in beneficial bacterial populations in the HFD + OVA + NP cohort. Weighted Gene Co-Expression Network Analysis (WGCNA) identified a negative correlation between NPs exposure or OVA sensitization and the expression of Slc1a1, Slc5a8, and Mep1a, while a positive correlation was observed with Aa467197 expression. These findings indicate that oral exposure to PS-NPs exacerbates OVA-induced food allergies, particularly in the context of an HFD, through mechanisms involving increased intestinal permeability, gut microbial dysbiosis, and gene expression modulation. This study highlights the potential health hazards posed by environmental microplastic contamination and its possible contribution to the escalating incidence of food allergies.

A Cascade of Microbiota-Leaky Gut-Inflammation- Is it a Key Player in Metabolic Disorders?

PURPOSE OF REVIEW

This review addresses critical gaps in knowledge and provides a literature overview of the molecular pathways connecting gut microbiota dysbiosis to increased intestinal permeability (commonly referred to as "leaky gut") and its contribution to metabolic disorders. Restoring a healthy gut microbiota holds significant potential for enhancing intestinal barrier function and metabolic health. These interventions offer promising therapeutic avenues for addressing leaky gut and its associated pathologies in metabolic syndrome.

RECENT FINDINGS

In metabolic disorders such as obesity and type 2 diabetes (T2D), beneficial microbes such as those producing short-chain fatty acids (SCFAs) and other key metabolites like taurine, spermidine, glutamine, and indole derivatives are reduced. Concurrently, microbes that degrade toxic metabolites such as ethanolamine also decline, while proinflammatory, lipopolysaccharide (LPS)-enriched microbes increase. These microbial shifts place a higher burden on intestinal epithelial cells, which are in closest proximity to the gut lumen, inducing detrimental changes that compromise the structural and functional integrity of the intestinal barrier. Such changes include exacerbation of tight junction protein (TJP)s dysfunction, particularly through mechanisms such as destabilization of zona occludens (Zo)-1 mRNA or post-translational modifications. Emerging therapeutic strategies including ketogenic and Mediterranean diets, as well as probiotics, prebiotics, synbiotics, and postbiotics have demonstrated efficacy in restoring beneficial microbial populations, enhancing TJP expression and function, supporting gut barrier integrity, reducing leaky gut and inflammation, and ultimately improving metabolic disorders. This review summarizes the mechanisms by which gut microbiota contribute to the development of leaky gut and inflammation associated with metabolic syndrome. It also explores strategies for restoring gut microbiota balance and functionality by promoting beneficial microbes, increasing the production of beneficial metabolites, clearing toxic metabolites, and reducing the proportion of proinflammatory microbes. These approaches can alleviate the burden on intestinal epithelial cells, reduce leaky gut and inflammation, and improve metabolic health.

Gut microbiota, inflammatory proteins and bone mineral density in different age groups: A Mendelian randomization study

Several studies have indicated a potential association between gut microbiota and bone density. However, the causal relationship between gut microbiota and bone mineral density across different age groups, as well as the potential role of inflammatory proteins as mediators, remains unclear. Gut microbiota, inflammatory proteins, and bone mineral density (BMD) were identified in various age groups using summary data from large-scale genome-wide association studies. Mendelian randomization was employed to examine the causal connections between gut microbiota, inflammatory proteins, and BMD in different age groups, primarily utilizing inverse variance weighted as the statistical method. Furthermore, the potential role of inflammatory proteins as mediators in the pathway from gut microbiota to BMD was investigated. Eight positive and 19 negative causal relationships between gut microbiota and BMD were observed across various age groups. We also identified 14 positive and 8 negative causal relationships between inflammatory proteins and BMD in different age groups. Inflammatory proteins did not appear to function as mediators in the pathway from gut microbiota to BMD. Gut microbiota and inflammatory proteins were causally linked to BMD; however, inflammatory proteins did not seem to function as mediators in the pathway from gut microbiota to BMD because the effects of intestinal flora on bone density and the effects of inflammatory factors on bone density were in different directions.

High-fat diet induces sarcopenic obesity in natural aging rats through the gut-trimethylamine N-oxide-muscle axis

INTRODUCTION

The lack of suitable animal models for sarcopenic obesity (SO) limits in-depth research into the disease. Emerging studies have demonstrated that gut dysbiosis is involved in the development of SO. As the importance of microbial metabolites is starting to unveil, it is necessary to comprehend the specific metabolites associated with gut microbiota and SO.

OBJECTIVES

We aimed to investigate whether high-fat diet (HFD) causes SO in natural aging animal models and specific microbial metabolites that are involved in linking HFD and SO.

METHODS

Young rats received HFD or control diet for 80 weeks, and obesity-related metabolic disorders and sarcopenia were measured. 16S rRNA sequencing and non-targeted and targeted metabolomics methods were used to detect fecal gut microbiota and serum metabolites. Gut barrier function was evaluated by intestinal barrier integrity and intestinal permeability. Trimethylamine N-oxide (TMAO) treatment was further conducted for verification.

RESULTS

HFD resulted in body weight gain, dyslipidemia, impaired glucose tolerance, insulin resistance, and systemic inflammation in natural aging rats. HFD also caused decreases in muscle mass, strength, function, and fiber cross-sectional area and increase in muscle fatty infiltration in natural aging rats. 16S rRNA sequencing and nontargeted and targeted metabolomics analysis indicated that HFD contributed to gut dysbiosis, mainly characterized by increases in deleterious bacteria and TMAO. HFD destroyed intestinal barrier integrity and increased intestinal permeability, as evaluated by reducing levels of colonic mucin-2, tight junction proteins, goblet cells and elevating serum level of fluorescein isothiocyanate-dextran 4. Correlation analysis showed a positive association between TMAO and SO. In addition, TMAO treatment aggravated the development of SO in HFD-fed aged rats through regulating the ROS-AKT/mTOR signaling pathway.

CONCLUSION

HFD leads to SO in natural aging rats, partially through the gut-microbiota-TMAO-muscle axis.

Start small, think big: MicroRNAs in diabetes mellitus and relevant cardiorenal-liver metabolic health spectrum

Diabetes mellitus (DM), co-existing with metabolic disorder of cardio-renal-liver, is one of the most difficult problems in medicine that attracts global concern with high mortality. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that negatively regulates gene expression and exerts active against a large proportion of the transcriptome, due to their high evolutionary conservation. Emerging evidence prove that miRNAs are involved in the pathogenesis of DM and associated metabolic disorders, manifested by their variable alteration in the blood, urine, tissues, or organs, principally contributing to modulate the interconnections between DM and cardio-renal-liver metabolism. Mechanistically, miRNAs regulate various biological processes, such as metabolism of insulin, lipid, glucose, inflammatory response, fibrosis, oxidative stress, apoptosis, and angiogenesis, etc. This review emphasizes the function of miRNAs and highlights the physiopathological regulation of miRNA in DM and related complications, especially the dysfunction of cardiovascular system, kidneys, and liver, with the aim of providing promising biomarkers for assisting early diagnosis of DM with cardio-renal-liver- specific metabolic disorders, as well as for the development of miRNA-targeting agents.

Probiotics Exert Gut Immunomodulatory Effects by Regulating the Expression of Host miRNAs

Probiotics exert a diverse range of immunomodulatory effects on the human gut immune system. These mechanisms encompass strengthening the intestinal mucosal barrier, inhibiting pathogen adhesion and colonization, stimulating immune modulation, and fostering the production of beneficial substances. As a result, probiotics hold significant potential in the prevention and treatment of various conditions, including inflammatory bowel disease and colorectal cancer. A pivotal mechanism by which probiotics achieve these effects is through modulating the expression of host miRNAs. miRNAs, non-coding RNA molecules, are vital regulators of fundamental biological processes like cell growth, differentiation, and apoptosis. By interacting with mRNAs, miRNAs can either promote their degradation or repress their translation, thereby regulating gene expression post-transcriptionally and modulating the immune system. This review provides a comprehensive overview of how probiotics modulate gut immune responses by altering miRNA expression levels, both upregulating and downregulating specific miRNAs. It further delves into how this modulation impacts the host's resistance to pathogens and susceptibility to diseases, offering a theoretical foundation and practical insights for the clinical utilization of probiotics in disease prevention and therapy.

Gut microbiome and serum metabolites in neuropathic pain: The PPARα perspective

Neuropathic pain (NP) is a chronic disease state centred on neuroinflammation with a high prevalence and limited effective treatment options. Peroxisome proliferator-activated receptor α (PPARα) has emerged as a promising target for NP management due to its anti-inflammatory properties. Recent evidence highlights the critical role of the gut microbiome and its metabolites in NP pathogenesis. This study aimed to investigate whether PPARα modulates the development and alleviation of NP by influencing gut microbial communities and serum metabolites. 16S rDNA sequencing and liquid chromatography-mass spectrometry (LC-MS/MS) untargeted metabolomics analyses performed 14 days after the establishment of a chronic constriction injury (CCI) pain model in C57BL/6 J mice showed significant changes in gut microbial and metabolite levels in CCI mice. Intraperitoneal injection of the PPARα agonist GW7647 (5 mg/kg) significantly attenuated mechanical allodynia and thermal hyperalgesia in CCI mice, whereas injection of the PPARα antagonist GW6471 (20 mg/kg) produced the opposite effect. Immunofluorescence analysis revealed that GW7647 effectively suppressed microglial activation. Additionally, PPARα agonist and antagonist treatments markedly altered the composition and abundance of intestinal microbial communities in CCI mice. Further serum LC-MS/MS analysis identified 258 potential serum metabolic biomarkers, many of which correlated with changes in gut microbial composition. These findings demonstrate that PPARα influences serum metabolite profiles by modulating gut microbiota composition, which subsequently affects NP progression. This study provides novel insights into the mechanisms underlying NP and suggests potential therapeutic avenues targeting PPARα and gut microbiota.

Fecal microbiota transplantation: application scenarios, efficacy prediction, and factors impacting donor-recipient interplay

Fecal microbiota transplantation (FMT) represents a therapeutic approach that directly regulates the gut microbiota of recipients, normalizes its composition and reaping therapeutic rewards. Currently, in addition to its general application in treating Clostridium difficile (C. difficile) infection (CDI), FMT treatment has also been extended to the fields of other gastrointestinal diseases, infections, gut-liver or gut-brain axis disorders, metabolic diseases and cancer, etc. Prior to FMT, rigorous donor screening is essential to reduce the occurrence of adverse events. In addition, it is imperative to evaluate whether the recipient can safely and effectively undergo FMT treatment. However, the efficacy of FMT is influenced by the complex interactions between the gut microbiota of donor and recipient, the degree of donor microbiota engraftment is not necessarily positively related with the success rate of FMT. Furthermore, an increasing number of novel factors affecting FMT outcomes are being identified in recent clinical trials and animal experiments, broadening our understanding of FMT treatment. This article provides a comprehensive review of the application scenarios of FMT, the factors influencing the safety and efficacy of FMT from the aspects of both the donors and the recipients, and summarizes how these emerging novel regulatory factors can be combined to predict the clinical outcomes of patients undergoing FMT.

Obese Adipose Tissue Extracellular Vesicles Activate Mitochondrial Fatty Acid β-oxidation to Drive Colonic Stemness

BACKGROUND & AIMS

Patients with obesity and mouse models of obesity exhibit abnormalities in intestinal epithelial cells, including enhanced stemness. Adipose tissue (AT) is the largest endocrine organ secreting cytokines, hormones, and extracellular vesicles (EVs). Here, we characterized EV protein cargo from obese and non-obese AT and demonstrate the role of obese adipose-derived EVs in enhancing colonic stemness.

METHODS

EVs were isolated from visceral AT from mice fed high-fat diet to induce obesity or control matched-diet. EV cargo was characterized by unbiased proteomics. Mouse colonoids were treated with EVs and analyzed for fatty acid β-oxidation (FAO), expression of stem marker genes, stem function, and β-catenin expression and acetylation. Mice deficient in adipocyte-specific Tsg101 expression were generated to alter adipocyte EV protein cargo, and colonic stemness was measured.

RESULTS

EVs secreted from obese visceral AT (Ob EVs) were significantly enriched with acyl-CoA dehydrogenase long chain (ACADL), an initiator enzyme of FAO. Compared with non-obese EVs, colonoids treated with Ob EVs exhibited increased exogenous ACADL protein expression, FAO, growth, persistence of stem/progenitor function, and increased β-catenin protein expression and acetylation that was abolished by FAO inhibition. Mice deficient in adipocyte-specific Tsg101 expression exhibited Ob EVs with altered protein expression profiles and were protected from obesity-induced enhanced colonic stemness.

CONCLUSIONS

The contents of Ob EVs are poised to fuel FAO and to promote obesity-induced stemness in the colon. Alteration of metabolism is a key mechanism of adipose-to-intestinal tissue communication elicited by EVs, thereby influencing basal colonic stem cell homeostasis during obesity.

Comparative analysis of gut microbiota in healthy and diarrheic foals

Diarrhea presents a substantial risk of high morbidity and mortality among foals. Although studies have shown connections between gut microbiota and several gastrointestinal diseases, there is still inadequate information on gut microbial alterations in foals during diarrhea. In this study, we conducted 16S rRNA and ITS gene amplicon sequencing to investigate gut bacterial and fungal differences between healthy and diarrheic foals. The results unveiled significant reductions in gut bacterial and fungal diversities among foals experiencing diarrhea, accompanied by notable shifts in the composition of gut microbial communities. A considerable decrease was observed in the relative abundance of 30 bacterial and 34 fungal genera. Moreover, two bacterial and eight fungal genera were utterly undetectable in the gut microbiota of diarrheic foals. Some decreased genera, such as Bifidobacterium and Saccharomyces, were deemed beneficial and recognized as probiotics. The study revealed significant alterations in foals' gut bacterial and fungal communities during diarrhea, which enriched our comprehension of gut microbial dynamics in foals across varying health statuses. These findings offer valuable insights for managing diarrhea through gut microbiota modulation, suggesting that probiotics may be superior to antibiotics in preventing and controlling foal diarrhea.IMPORTANCEThis research advances the understanding of gut bacterial and fungal dynamics in foals, highlighting gut microbiota dysbiosis as a potential contributor to foal diarrhea. Additionally, we observed that many altered bacteria and fungi were downregulated during diarrhea, including some probiotic strains. Consequently, our findings provide evidence that probiotics may offer superior efficacy compared with antibiotics as potential candidates for preventing and treating foal diarrhea.

Impact of sodium butyrate on stroke-related intestinal injury in diabetic mice: Interference with Caspase-1/GSDMD pyroptosis pathway and preservation of intestinal barrier

Diabetic stroke-associated acute intestinal injury is characterized by high mortality, disability, and poor prognosis due to the lack of effective therapies. Our prior research demonstrated that administration of 300 mg/kg sodium butyrate (NaB) can improve neurological outcomes post-diabetic stroke. Nonetheless, whether the effect of NaB is related to intestinal regulation, along with its underlying mechanisms, remains uncertain. This study aims to investigate the effects and mechanistic pathways of NaB on diabetic stroke-associated acute intestinal injury. A middle cerebral artery occlusion/reperfusion model was established in mice with streptozotocin-induced diabetes. The results demonstrated that NaB alleviated colonic injury 24 h after reperfusion in diabetic stroke. Pyroptosis-related protein levels in colonic tissues were significantly elevated following diabetic stroke but were markedly reduced with NaB treatment. NaB also improved gut barrier integrity and reduced inflammation, promoting epithelial barrier self-repair. In the NaB combined with lipopolysaccharide group, lipopolysaccharide administration induced a significant inflammatory response in the colonic tissue. Conversely, treatment with NaB and VX-765 (an inhibitor for Caspase-1) led to a notable alleviation in intestinal inflammation. These findings suggest that NaB mitigates colonic injury and enhances barrier function following diabetic stroke, potentially through the Caspase-1/Gasdermin D pyroptosis pathway. This study may provide a novel strategy and direction for intestinal rehabilitation in diabetic stroke patients.

New thoughts on the gut-immune axis of arthritis

Arthritis is associated with varying degrees of intestinal inflammation and microbiota dysbiosis, leading to the 'gut-joint axis hypothesis' in which intestinal and joint inflammation are suggested to be interconnected through immune-microbiota interactions. While clinical observations support this, causality remains uncertain. Rodent models have provided insights into potential mechanisms by uncovering microbial influences and immune pathways that either connect or uncouple gut and joint inflammation. Based on recent findings, we propose the 'immune hypersensitivity hypothesis' whereby central immune hyper-reactivity can independently drive joint inflammation via local sterile triggers, and gut inflammation via microbial triggers. We argue that this suggests a more nuanced role of the microbiota in arthritis pathogenesis that varies according to the predominant immune mechanisms in disease subtypes. We explore gut-immune interactions in arthritis, highlight ongoing challenges, and propose future research directions.

Akkermansia muciniphila Modulates Central Nervous System Autoimmune Response and Cognitive Impairment by Inhibiting Hippocampal NLRP3-Mediated Neuroinflammation

BACKGROUND

Numerous studies have demonstrated the significant role of Akkermansia muciniphila (A. muciniphila) in enhancing host immune responses and metabolic functions. However, its increased presence in multiple sclerosis (MS) patients has led to a focus on the relationships between A. muciniphila and diseases, with the underlying mechanisms remaining unknown.

METHOD

Solochrome cyanin, hematoxylin-eosin staining (H&E) and immunofluorescence staining were used to assess demyelination and inflammation. Gut microbiota changes were examined by 16S rRNA sequencing. Intracellular cytokine levels were assessed by flow cytometry. Cognitive impairment was evaluated using four behavioral tests. Intestinal barrier function and pyrin domain-containing protein 3 (NLRP3)-mediated neuroinflammation were evaluated by immunoblotting.

RESULTS

We found that treatment with an appropriate dose of A. muciniphila (5.0 × 107 CFU/mL) reduced neuropathology and disease severity in experimental autoimmune encephalomyelitis (EAE) mice. In addition, A. muciniphila supplementation increased the diversity and abundance of intestinal microbiota while decreasing the Firmicutes/Bacteroidetes ratio. Moreover, it improved intestinal barrier function and attenuated Th17 responses in the gut, central nervous system (CNS), and lymphoid tissues, without affecting Treg response in the lymphoid tissue. Furthermore, A. muciniphila administration partly regulated cognitive impairment and hippocampal NLRP3-mediated neuroinflammation.

CONCLUSION

Our results suggest that A. muciniphila holds promise as a probiotic for treating NLRP3-associated inflammatory disorders and cognitive impairment, including MS.

Food supply toxicants and additives alter the gut microbiota and risk of metabolic disease

Metabolic disease is rising along with both global industrialization and the use of new commercial, agricultural, and industrial chemicals and food additives. Exposure to these compounds may contribute to aspects of metabolic diseases such as obesity, diabetes, and fatty liver disease. Ingesting compounds in the food supply is a key route of human exposure, resulting in the interaction between toxicants or additives and the intestinal microbiota. Toxicants can influence the composition and function of the gut microbiota, and these microbes can metabolize and transform toxicants and food additives. Microbe-toxicant interactions in the intestine can alter host mucosal barrier function, immunity, and metabolism, which may contribute to the risk or severity of metabolic disease development. Targeting the connection between toxicants, food, and immunity in the gut using strategies such as fermentable fiber (i.e., inulin) may mitigate some of the effects of these compounds on host metabolism. Understanding causative factors in the microbe-host relationship that promote toxicant-induced dysmetabolism is an important goal. This review highlights the role of common toxicants (i.e., persistent organic pollutants, pesticides, and fungicides) and food additives (emulsifiers and artificial sweeteners) found in our food supply that alter the gut microbiota and promote metabolic disease development.

The microbiome's influence on obesity: mechanisms and therapeutic potential

In 2023, the World Obesity Atlas Federation concluded that more than 50% of the world's population would be overweight or obese within the next 12 years. At the heart of this epidemic lies the gut microbiota, a complex ecosystem that profoundly influences obesity-related metabolic health. Its multifaced role encompasses energy harvesting, inflammation, satiety signaling, gut barrier function, gut-brain communication, and adipose tissue homeostasis. Recognizing the complexities of the cross-talk between host physiology and gut microbiota is crucial for developing cutting-edge, microbiome-targeted therapies to address the global obesity crisis and its alarming health and economic repercussions. This narrative review analyzed the current state of knowledge, illuminating emerging research areas and their implications for leveraging gut microbial manipulations as therapeutic strategies to prevent and treat obesity and related disorders in humans. By elucidating the complex relationship between gut microflora and obesity, we aim to contribute to the growing body of knowledge underpinning this critical field, potentially paving the way for novel interventions to combat the worldwide obesity epidemic.

Bidirectional Interplay Among Non-Coding RNAs, the Microbiome, and the Host During Development and Diseases

It is widely known that the dysregulation of non-coding RNAs (ncRNAs) and dysbiosis of the gut microbiome play significant roles in host development and the progression of various diseases. Emerging evidence has highlighted the bidirectional interplay between ncRNAs and the gut microbiome. This article aims to review the current understanding of the molecular mechanisms underlying the crosstalk between ncRNAs, especially microRNA (miRNA), and the gut microbiome in the context of development and diseases, such as colorectal cancer, inflammatory bowel diseases, neurological disorders, obesity, and cardiovascular disease. Ultimately, this review seeks to provide a foundation for exploring the potential roles of ncRNAs and gut microbiome interactions as biomarkers and therapeutic targets for clinical diagnosis and treatment, such as ncRNA mimics, antisense oligonucleotides, and small-molecule compounds, as well as probiotics, prebiotics, and diets.

Identification of disease-specific gut microbial markers in vitiligo

There is a potential correlation between vitiligo and gut microbiota, although research in this area is currently limited. The research employed high-throughput sequencing of 16S rRNA to examine the gut microbiome in the stool samples of 49 individuals with vitiligo and 49 without the condition. The study encompassed four comparison groups: (1) DI (disease) group vs. HC (healthy control) group; (2) DI_m group (disease group of minors) vs. HC_m group (healthy control group of minors); (3) DI_a group (adult disease group) vs. HC_a group (adult healthy control group); (4) DI_m group vs. DI_a group. Research findings have indicated the presence of spatial heterogeneity in the gut microbiota composition between individuals with vitiligo and healthy controls. A significant reduction in gut microbiota diversity has been observed in vitiligo patients across both minors and adult groups. However, variations have been noted in the composition of disease-related differential microbial markers among different age groups. Specifically, Bacteroides and Parabacteroides have been identified as specific markers of the intestinal microbiota of vitiligo patients in both minor and adult groups. Correlative analyses have revealed a positive correlation of these two genera with the Vitiligo Area Scoring Index (VASI) and disease duration. It is noteworthy that there are no significant differences in diversity between the DI_m group and the DI_a group, with similarities in microbiota composition and functional characteristics. Nevertheless, correlative analyses suggest a declining trend in Bacteroides and Parabacteroides with increasing age. Individuals with vitiligo exhibit distinct features in their gut microbiome when contrasted with those in the healthy control group. Additionally, the microbial marker genera that show variances between patients and healthy controls vary among different age groups. Disease-specific microbial marker genera (Bacteroides and Parabacteroides) are associated with VASI, duration of the condition, and age. These findings are essential for improving early diagnosis and developing potential treatment strategies for individuals with vitiligo.

Probiotics alleviate painful diabetic neuropathy by modulating the microbiota-gut-nerve axis in rats

Painful diabetic neuropathy (PDN) is one of the most common complications of diabetes. Recent studies suggested that gut microbiota dysbiosis contributes to the development of PDN, but underlying mechanisms remain elusive. In this study, we found decreased probiotics generating bacteria such as Lactobacillus and Bifidobacterium strains in the PDN rats. Supplementation with multiple probiotics for 12 weeks alleviated pain, reversed nerve fiber lesions, and restored neuronal hyperexcitability. Probiotics administration effectively attenuated intestinal barrier impairment, reduced serum lipopolysaccharide and proinflammatory cytokines, and mitigated disruptions in the blood-nerve barrier. Furthermore, probiotics treatment inhibited the activation of the TLR4/MyD88/NF-κB signaling pathway and reduced proinflammatory cytokines in the sciatic nerve of the PDN rats. Together, our findings suggest that gut microbiota dysbiosis participates in PDN pathogenesis, and probiotics offer therapeutic potential via modulating the microbiota-gut-nerve axis.

Gut-X axis

Recent advances in understanding the modulatory functions of gut and gut microbiota on human diseases facilitated our focused attention on the contribution of the gut to the pathophysiological alterations of many extraintestinal organs, including the liver, heart, brain, lungs, kidneys, bone, skin, reproductive, and endocrine systems. In this review, we applied the "gut-X axis" concept to describe the linkages between the gut and other organs and discussed the latest findings related to the "gut-X axis," including the underlying modulatory mechanisms and potential clinical intervention strategies.

Role of Trained Immunity in Heath and Disease

PURPOSE OF REVIEW

This review aims to explore the role of immune memory and trained immunity, focusing on how innate immune cells like monocytes, macrophages, and natural killer cells undergo long-term epigenetic and metabolic rewiring. Specifically, it examines the mechanisms by which trained immunity, often triggered by infection or vaccination, could impact cardiac processes and contribute to both protective and pathological responses within the cardiovascular system.

RECENT FINDINGS

Recent research demonstrates that vaccination and infection not only activate immune responses in circulating monocytes and tissue macrophages but also affect immune progenitor cells within the bone marrow environment, conferring lasting protection against heterologous infections. These protective effects are attributed to epigenetic and metabolic reprogramming, which enable a heightened immune response upon subsequent encounters with pathogens. However, while trained immunity is beneficial in combating infections, it has been linked to exacerbated inflammation, which may increase susceptibility to cardiovascular diseases, including atherosclerosis and heart failure. Our review highlights the dual nature of trained immunity: while it offers protective advantages against infections, it also poses potential risks for cardiovascular health by promoting chronic inflammation. Understanding the molecular mechanisms underlying immune memory's impact on cardiac processes could lead to new therapeutic strategies to mitigate cardiovascular diseases, such as atherosclerosis, heart failure, and diabetes. These insights build the grounds for future research to balance the benefits of trained immunity with its potential risks in cardiovascular disease management.

Postbiotic Impact on Host Metabolism and Immunity Provides Therapeutic Potential in Metabolic Disease

The gut microbiota influences aspects of metabolic disease, including tissue inflammation, adiposity, blood glucose, insulin, and endocrine control of metabolism. Prebiotics or probiotics are often sought to combat metabolic disease. However, prebiotics lack specificity and can have deleterious bacterial community effects. Probiotics require live bacteria to find a colonization niche sufficient to influence host immunity or metabolism. Postbiotics encompass bacterial-derived components and molecules, which are well-positioned to alter host immunometabolism without relying on colonization efficiency or causing widespread effects on the existing microbiota. Here, we summarize the potential for beneficial and detrimental effects of specific postbiotics related to metabolic disease and the underlying mechanisms of action. Bacterial cell wall components, such as lipopolysaccharides, muropeptides, lipoteichoic acids and flagellin, have context-dependent effects on host metabolism by engaging specific immune responses. Specific types of postbiotics within broad classes of compounds, such as lipopolysaccharides and muropeptides, can have opposing effects on endocrine control of host metabolism, where certain postbiotics are insulin sensitizers and others promote insulin resistance. Bacterial metabolites, such as short-chain fatty acids, bile acids, lactate, glycerol, succinate, ethanolamine, and ethanol, can be substrates for host metabolism. Postbiotics can fuel host metabolic pathways directly or influence endocrine control of metabolism through immunomodulation or mimicking host-derived hormones. The interaction of postbiotics in the host-microbe relationship should be considered during metabolic inflammation and metabolic disease.

Protection of Alzheimer's disease progression by a human-origin probiotics cocktail

Microbiome abnormalities (dysbiosis) significantly contribute to the progression of Alzheimer's disease (AD). However, the therapeutic efficacy of microbiome modulators in protecting against these ailments remains poorly studied. Herein, we tested a cocktail of unique probiotics, including 5 Lactobacillus and 5 Enterococcus strains isolated from infant gut with proven microbiome modulating capabilities. We aimed to determine the probiotics cocktail's efficacy in ameliorating AD pathology in a humanized AD mouse model of APP/PS1 strains. Remarkably, feeding mice with 1 × 1011 CFU per day in drinking water for 16 weeks significantly reduced cognitive decline (measured by the Morris Water Maze test) and AD pathology markers, such as Aβ aggregation, microglia activation, neuroinflammation, and preserved blood-brain barrier (BBB) tight junctions. The beneficial effects were linked to a reduced inflammatory microbiome, leading to decreased gut permeability and inflammation in both systemic circulation and the brain. Although both male and female mice showed overall improvements in cognition and biological markers, females did not exhibit improvements in specific markers related to inflammation and barrier permeability, suggesting that the underlying mechanisms may differ depending on sex. In conclusion, our results suggest that this unique probiotics cocktail could serve as a prophylactic agent to reduce the progression of cognitive decline and AD pathology. This is achieved by beneficially modulating the microbiome, improving intestinal tight junction proteins, reducing permeability in both gut and BBB, and decreasing inflammation in the gut, blood circulation, and brain, ultimately mitigating AD pathology and cognitive decline.

Editorial for the special issue on "microbiomes in extremes of aging"

This special issue of the Journal of Experimental Gerontology explores the dynamic interplay between microbiomes and aging-related conditions. The four selected studies highlight the role of microbiota in Alzheimer's disease, cancer immunotherapy, myocardial infarction and tryptophan metabolism, providing insights into how microbiomes influence health and disease in aging. These studies underscore the potential for microbiome-targeted interventions to mitigate aging-related disorders and improve the quality of life for older adults.

Inflammation and resolution in obesity

Inflammation is an essential physiological defence mechanism, but prolonged or excessive inflammation can cause disease. Indeed, unresolved systemic and adipose tissue inflammation drives obesity-related cardiovascular disease and type 2 diabetes mellitus. Drugs targeting pro-inflammatory cytokine pathways or inflammasome activation have been approved for clinical use for the past two decades. However, potentially serious adverse effects, such as drug-induced weight gain and increased susceptibility to infections, prevented their wider clinical implementation. Furthermore, these drugs do not modulate the resolution phase of inflammation. This phase is an active process orchestrated by specialized pro-resolving mediators, such as lipoxins, and other endogenous resolution mechanisms. Pro-resolving mediators mitigate inflammation and development of obesity-related disease, for instance, alleviating insulin resistance and atherosclerosis in experimental disease models, so mechanisms to modulate their activity are, therefore, of great therapeutic interest. Here, we review current clinical attempts to either target pro-inflammatory mediators (IL-1β, NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome, tumour necrosis factor (TNF) and IL-6) or utilize endogenous resolution pathways to reduce obesity-related inflammation and improve cardiometabolic outcomes. A remaining challenge in the field is to establish more precise biomarkers that can differentiate between acute and chronic inflammation and to assess the functionality of individual leukocyte populations. Such advancements would improve the monitoring of drug effects and support personalized treatment strategies that battle obesity-related inflammation and cardiometabolic disease.

Suboptimal vitamin D status and overweight/obesity are associated with gut integrity and inflammation in minority children and adolescents: A cross-sectional analysis from the MetA-bone trial

Preserving gut integrity is essential to preventing the development of chronic diseases. Several factors are associated with gut integrity and inflammation in adults. However, there is limited evidence in healthy children. This study evaluated the factors associated with gut integrity and inflammation in healthy children participating in the MetA-Bone trial. We hypothesized that age, sex, race/ethnicity, diet, vitamin D, and body composition will be associated with gut integrity and inflammation. Socio-demographic variables were collected with a questionnaire. Measures included markers of gut integrity (Intestinal Fatty Acid Binding Protein; I-FABP), and inflammation (IL-17 and calprotectin) determined by ELISA in 24-h urine and serum; serum 25(OH)D concentration (commercial lab), BMI percentile, and diet (24-h recalls). Analyses included descriptive statistics, chi-square, and adjusted logistic regressions. Participants (n=138) median age was 12.4 (11.1-13.3), 53.6% were male, 9.4% were Black/African American, and 71.1% were Hispanic/Latino. Children with suboptimal vitamin D were 3.35 times more likely to present gut integrity damage (elevated I-FABP) than those with optimal status (P = .005). Overweight/obesity and fructose intake were associated with inflammation (elevated calprotectin) (P < .05). Those with lower gut integrity damage had lower odds of having higher inflammation (P = .021). Other factors were not associated with inflammation. Suboptimal vitamin D status, overweight/obesity and inflammation may compromise the gut integrity in healthy children, suggesting an impairment on the intestinal barrier repair system. More research with a longitudinal design is needed to gain a deeper understanding of the role of additional factors linked to gut integrity and inflammation in healthy children.

Mechanism of miR-130b-3p in relieving airway inflammation in asthma through HMGB1-TLR4-DRP1 axis

Asthma is a chronic inflammatory respiratory disease characterized by recurrent breathing difficulties caused by airway obstruction and hypersensitivity. Although there is diversity in their specific mechanisms, microRNAs (miRNAs) have a significant impact on the development of asthma. Currently, the contribution of miR-130b-3p to asthma remains elusive. The goal of this study was to examine whether miR-130b-3p attenuates house dust mite (HDM)-induced asthma through High-mobility group box protein 1 (HMGB1)/Toll-like receptor 4 (TLR4)/mitochondrial fission protein (DRP1) signaling pathway. We elucidate that miR-130b-3p can bind to the HMGB1 3'UTR, attenuating HMGB1 mRNA and protein levels, and nucleo-cytoplasmic translocation of HMGB1. We observed that miR-130b-3p agomir or HMGB1 CKO attenuated HDM-induced airway inflammation and hyperresponsiveness, and decreased Th2-type cytokines in bronchoalveolar lavage fluid (BALF) and mediastinal lymph nodes. Further, HMGB1 CKO contributes to alleviating Th2 inflammation in AT-II cells (CD45.2-/CD31-/Epcam-+/proSP-C+/MHC-II+) from lung single cell suspensions of asthmatic mice by flow cytometry. Our findings identified miR-130b-3p as a potent regulator in asthma that exerts its anti-inflammatory effects by targeting HMGB1 and the subsequent HMGB1/TLR4/DRP1axis, presenting a prospective novel therapeutic avenue for asthma management.

Acupuncture for hormonal readiness and gut microbiota in obese polycystic ovary syndrome: an open-label, randomized controlled trial

Objective

To explore whether acupuncture combined with clomiphene can reduce the luteinizing hormone-to follicle-stimulating hormone ratio and impact the gut microbiota in patients with obese polycystic ovary syndrome.

Methods

This open-label, randomized, parallel-group controlled trial included 86 women aged 20-40 years with obese polycystic ovary syndrome and 19 healthy controls. Participants were randomly assigned to either an acupuncture combined with clomiphene group or a clomiphene-only group, with a healthy control group for comparison. The treatment lasted three menstrual cycles, with acupuncture administered three times weekly and clomiphene given daily from day five of menstruation for five consecutive days per cycle. The primary outcome was the change in the luteinizing hormone-to-follicle-stimulating hormone (LH/FSH) ratio. Secondary outcomes included levels of other sex hormones, glucose and lipid metabolism parameters, self-rating anxiety and depression scale scores, and gut microbiota composition.

Results

Intention-to-treat analysis showed that the adjusted mean luteinizing hormone-to follicle-stimulating hormone ratio decrease was -0.8 (95% CI: -1.14 to -0.46) in the acupuncture combined with clomiphene group and -0.22 (95% CI: -0.47 to 0.01) in the clomiphene group. The adjusted between-group difference was 0.53 (95% CI: 0.24 to 0.82, p < 0.001). The levels of Agathobacter faecis increased, and those of Erysipelatoclostridium spiroforme, Streptococcus lutetiensis, and Lactococcus lactis decreased after acupuncture combined with clomiphene treatment (p < 0.05).

Conclusion

Acupuncture combined with clomiphene may be safe and effective, reduce the luteinizing hormone-to follicle-stimulating hormone ratio, and improve insulin resistance in obese polycystic ovary syndrome, and these outcomes may be related to the gut microbiota.

Exposure to toluene diisocyanate induces dysbiosis of gut-lung homeostasis: Involvement of gut microbiota

Toluene diisocyanate (TDI) is a major industrial compound that induces occupational asthma with steroid-resistant properties. Recent studies suggest that the gastrointestinal tract may be an effective target for the treatment of respiratory diseases. However, the alterations of the gut-lung axis in TDI-induced asthma remain unexplored. Therefore, in this study, a model of stable occupational asthma caused by TDI exposure was established to detect the alteration of the gut-lung axis. Exposure to TDI resulted in dysbiosis of the gut microbiome, with significant decreases in Barnesiella_intestinihominis, Faecalicoccus_pleomorphus, Lactobacillus_apodemi, and Lactobacillus_intestinalis, but increases in Alistipes_shahii and Odoribacter_laneus. The largest change in abundance was in Barnesiella_intestinihominis, which decreased from 12.14 per cent to 6.18 per cent. The histopathological abnormalities, including shorter length of intestinal villi, thinner thickness of muscularis, reduced number of goblet cells and inflammatory cell infiltration, were found in TDI-treated mice compared to control mice. In addition, increased permeability (evidenced by significantly reduced levels of ZO-1, Occludin and Claudin-1) and activation of TLR4/NF-κB signaling were observed in the intestine of these TDI-exposed mice. Concurrently, exposure to TDI resulted in airway hyperresponsiveness, overt cytokine production (e.g., IL-4, IL-5, IL-13, IL-25, and IL-33), and elevated IgE level within the respiratory tract. The expression of tight junction proteins is reduced and TLR4/NF-κB signaling is activated in the lung following TDI treatment. In addition, correlation analyses showed that changes in the gut microbiota were correlated with TDI exposure-induced airway inflammation. In conclusion, the present study suggests that the immune gut-lung axis may be involved in the development of TDI-induced asthma, which may have implications for potential interventions against steroid-resistant asthma.

Interplay of Oxidative Stress, Gut Microbiota, and Nicotine in Metabolic-Associated Steatotic Liver Disease (MASLD)

Oxidative stress has been described as one of the main drivers of intracellular damage and metabolic disorders leading to metabolic syndrome, a major health problem worldwide. In particular, free radicals alter lipid metabolism and promote lipid accumulation in the liver, existing in the hepatic facet of metabolic syndrome, the metabolic dysfunction-associated steatotic liver disease (MASLD). Recent literature has highlighted how nicotine, especially if associated with a high-fat diet, exerts a negative effect on the induction and progression of MASLD by upregulating inflammation and increasing oxidative stress, abdominal fat lipolysis, and hepatic lipogenesis. Moreover, considerable evidence shows the central role of intestinal dysbiosis in the pathogenesis of MASLD and the impact of nicotine-induced oxidative stress on the gut microbiome. This results in an intricate network in which oxidative stress stands at the intersection point between gut microbiome, nicotine, and MASLD. The aim of this review is to delve into the molecular mechanisms linking tobacco smoking and MASLD, focusing on nicotine-induced microbiota modifications and their impact on MASLD development.

Excessive hydrogen sulfide-induced activation of NMDA receptors in the colon participates in anxiety- and compulsive-like behaviors in a rodent model of hemorrhagic shock and resuscitation

OBJECTIVE

Hemorrhagic shock and resuscitation (HSR) cause inflammatory responses in the gastrointestinal tract and is associated with substantial morbidity and mortality rates. Hydrogen sulfide (H2S), a gasotransmitter with pleiotropic activity, exhibits anti-inflammatory benefits at physiological levels. However, deleterious effects are observed when its concentration increases. In this investigation, we employed a mouse model of HSR to examine the effects of an H2S scavenger on the gastrointestinal tract and brain, with emphasis on N-Methyl-d-Aspartate (NMDA) receptor function.

METHODS

Mice were immediately administered dl-propargylglycine (PAG) intragastrically as an H2S scavenger after HSR exposure. The O-maze and buried beads tests were used to assess compulsive- and anxiety-like behaviors. Pathological changes in the intestine were evaluated at 24 and 30 days after HSR. Subsequently, at 30 days after HSR, we examined electrophysiological and pathological changes in the amygdala.

RESULTS

Within 24 h of HSR exposure, animals treated with PAG showed significantly lower colonic injury. Additionally, compared to the HSR-treated mice 30 days after HSR, the PAG-treated mice displayed reduced buried beads, increased open-arm time, lower blood levels of Diamine Oxidase (DAO) and considerably improved ZO-1 intensity, a stronger association between the delta rhythm phase and beta activity amplitude, and lower neuroinflammatory response in the amygdala. MK-801, an NMDA receptor inhibitor, significantly reversed H2S-induced intestinal and cerebral injury.

CONCLUSION

This experimental data suggests that H2S-induced excessive activation of NMDA receptors contributes to anxiety- and compulsive-like behaviors caused by HSR.

Targeted and untargeted lipidomics with integration of liver dynamics and microbiome after dietary reversal of obesogenic diet targeting inflammation-resolution signaling in aging mice

Obesity, a global epidemic linked to around 4 million deaths yearly, arises from lifestyle imbalances impacting inflammation-related conditions like non-alcoholic fatty liver disease and gut dysbiosis. But the long-term effects of inflammation caused by lifestyle-related dietary changes remain unexplained. In this study, we used young male C57Bl/6 mice which were fed either an obesogenic diet (OBD) or a control diet (CON) for six months. Later, a group of mice from the OBD group were intervened to the CON diet (OBD-R) for four months, while another OBD group remained on the OBD diet. The OBD induced distinct changes in gut microbial, notably elevating Firmicutes and Actinobacteria, while reducing Bacteroidetes and Tenericutes. OBD-R restored microbial abundance like CON. Analyzing liver, plasma, and fecal samples revealed OBD-induced alterations in various structural and bioactive lipids, which were normalized to CON in the OBD-R, showcasing lipid metabolism flexibility and adaptability to dietary shifts. OBD increased omega 6 fatty acid, Arachidonic Acid (AA) and decreased omega 3-derived lipid mediators in the OBD mimicking non-alcoholic fatty liver disease thus impacting inflammation-resolution pathways. OBD also induced hepatic inflammation via increasing alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and proinflammatory markers CCR2, TNF-α, and IL-1β in liver. Transitioning from OBD to CON mitigated inflammatory gene expression and restored lipid and cholesterol networks. This study underscores the intricate interplay between lifestyle-driven dietary changes, gut microbiota, lipid metabolism, and liver health. Notably, it suggests that shift from an OBD (omega-6 enriched) to CON partially alleviates signs of chronic inflammation during aging. Understanding these microbial, lipidomic, and hepatic inflammatory dynamics reveals potential therapeutic avenues for metabolic disorders induced by diet, emphasizing the pivotal role of diet in sustaining metabolic health.

Biotics as novel therapeutics in targeting signs of skin ageing via the gut-skin axis

Skin ageing is a phenomenon resulting from the aggregative changes to skin structure and function and is clinically manifested by physical features such as wrinkles, hyperpigmentation, elastosis, telangiectasia, and deterioration of skin barrier integrity. One of the main drivers of skin ageing, UV radiation, negatively influences the homeostasis of cells and tissues comprising the skin by triggering production of immune-mediated reactive oxygen species (ROS) and pro-inflammatory cytokines, as well as a various hormones and neuropeptides. Interestingly, an established link between the gut and the skin coined the 'gut-skin axis' has been demonstrated, with dysbiosis and gut barrier dysfunction frequently observed in certain inflammatory skin conditions and more recently, implicated in skin ageing. Therapeutic use of 'biotics' including prebiotics, probiotics, postbiotics, and synbiotics, which modulate the gut microbiota and production of microbially associated metabolites, influence the activity of the gut mucosal and immune systems and are showing promise as key candidates in addressing signs of skin ageing. In this review we aim to focus on the structure and function of the gut-skin axis and showcase the recent in-vitro and clinical evidence demonstrating the beneficial effects of select biotics in targeting signs of skin ageing and discuss the proposed mechanisms mediated via the gut-skin axis underpinning these effects.

Mucosal Hub Bacteria as Potential Targets for Improving High-Fat Diet-Related Intestinal Barrier Injury

Background: Intestinal barrier injury contributes to multiple diseases such as obesity and diabetes, whereas no treatment options are available. Methods: Due to close interactions between mucosal microbiome and intestinal barrier, we evaluated the potential of mucosal bacteria in providing targets for high-fat diet (HFD)-related intestinal barrier injury. Whole-genome metagenomics was used to evaluate mucosal microbiome, while intestinal barrier injury was estimated using serum LPS, FITC-dextran intensity, and ZO-1 protein. Results: We found that HFD induced significant fat accumulation in epididymal tissue at weeks 4 and 12, while ALT, LDL, and TC increased at week 12. Intestinal barrier injury was confirmed by elevated serum LPS at both weeks, upregulated FITC-dextran intensity, and decreased ZO-1 protein at week 12. Fourteen species such as Phocaeicola vulgatus differed in HFD-fed mice. The co-occurrence network of mucosal microbiome shifted from scale-free graph in controls to nearly random graph in HFD-fed mice. Besides, 10 hub bacteria especially Bacteroides ovatus decreased drastically in both mucosal and fecal samples of HFD-fed mice, correlated with intestinal permeability, ALT, and KEGG pathways such as "Mitochondrial biogenesis" and "metabolism". Moreover, Bacteroides ovatus has been confirmed to improve intestinal barrier function in a recent study. Conclusion: Mucosal hub bacteria can provide potential targets for improving HFD-related intestinal barrier function.

Effects of an Innovative High-Fat Diet on Intestinal Structure, Barrier Integrity, and Inflammation in a Zebrafish Model of Visceral Obesity

High-fat diet (HFD)-induced obesity is a global health concern associated with gastrointestinal disorders. While mammalian models have elucidated the effects of a HFD on intestinal structure and function, its impact on zebrafish, a crucial model for studying diet-induced obesity and gastrointestinal dysfunction, remains inadequately characterized. This study investigated the influence of a HFD on zebrafish intestinal morphology, tight junction (TJ) protein expression, and inflammatory markers. Zebrafish fed a control diet or HFD with 40% or 60% fat exhibited significant alterations in intestinal morphology, with increased villi number but reduced villi width and length, suggesting compensatory responses to dietary stress. TJ protein expression (Claudin 2, Claudin 3, and Claudin 10) showed complex changes, particularly in the HFD60 juvenile group, indicating a multifaceted response in barrier integrity. Pro-inflammatory cytokine IL-6 and TNF-α levels were lower in both the juvenile and adult HFD60 groups than in the HFD40 and control groups, while elevated anti-inflammatory IL-10 levels in HFD60 adult zebrafish suggested activation of compensatory mechanisms. These findings highlight zebrafish as a valuable model for studying the effects of HFD on intestinal health and provide insights into the relationship between dietary fat, gut dysfunction, and inflammation.

Host metabolic inflammation fueled by bacterial DNA

Metabolic diseases, characterized by chronic low-grade inflammation, exhibit a compromised gut barrier allowing the translocation of bacteria-derived products to bloodstream and distant metabolic organs. Bacterial DNA can be detected in metabolic tissues during the onset of these diseases, highlighting its role in the development of metabolic diseases. Extracellular vesicles (EVs) are involved in the delivery of bacterial DNA to the local tissues, and its sensing by the host triggers local and system inflammation. Understanding bacterial DNA translocation and its induced inflammation is crucial in deciphering metabolic disease pathways. Here, we delve into the mechanisms dictating the interaction between host physiology and bacterial DNA, focusing on its origin and delivery, host immune responses against it, and its roles in metabolic disorders.

Back to Roots: Dysbiosis, Obesity, Metabolic Syndrome, Type 2 Diabetes Mellitus, and Obstructive Sleep Apnea-Is There an Objective Connection? A Narrative Review

In recent decades, it has become clear that the gut is more than just a digestive organ; it also functions as an immune organ with regulatory capabilities and acts as a "second brain" that influences brain function due to the presence and regulatory roles of the gut microbiota (GM). The GM is a crucial component of its host and significantly impacts human health. Dysbiosis, or microbial imbalance, has been closely linked to various diseases, including gastrointestinal, neurological, psychiatric, and metabolic disorders. The aim of this narrative review is to highlight the roles of the GM in maintaining metabolic health. Sleep is a vital biological necessity, with living organisms having evolved an internal sleep-wake rhythm that aligns with a roughly 24 h light/dark cycle, and this is known as the circadian rhythm. This cycle is essential for tissue repair, restoration, and overall optimal body functioning. Sleep irregularities have become more prevalent in modern society, with fast-paced lifestyles often disrupting normal sleep patterns. Urban living factors, such as fast food consumption, shift work, exposure to artificial light and nighttime noise, medications, and social activities, can adversely affect circadian rhythms, with dysbiosis being one of the many factors incriminated in the etiology of sleep disorders.

Disrupted balance between pro-inflammatory lipid mediators and anti-inflammatory specialized pro-resolving mediators is linked to hyperinflammation in patients with alcoholic hepatitis

Background

Alcoholic hepatitis (AH) is characterized by intense systemic and liver inflammation, posing significant risks of health complications and mortality. While inflammation is a crucial defense mechanism against injury and infection, its timely resolution is essential to prevent tissue damage and restore tissue homeostasis. The resolution of inflammation is primarily governed by specialized pro-resolving mediators (SPMs), lipid metabolites derived from w-6 and w-3 poly-unsaturated fatty acids (PUFAs). Currently, the balance between pro-inflammatory lipid mediators (PLMs) and SPMs in the w-6 and w-3 PUFA metabolic pathways and the impact of alcohol abstinence on profiles of PLMs and SPMs in AH patients are not well studied.

Methods

In this study, we used LC-MS/MS and ELISA to quantify levels of lipid mediators (LMs) and their precursors in the plasma samples from 58 AH patients, 29 heavy drinkers without overt liver diseases (HDCs), and 35 healthy controls (HCs). Subsequently, we assessed correlations of altered LMs with clinical parameters and inflammatory mediators. Furthermore, we conducted a longitudinal study to analyze the effects of alcohol abstinence on LMs over 6- and 12-month follow-ups.

Results

AH patients exhibited significantly higher plasma levels of w-6 PLMs (PGD2 and LTB4) and SPM RvE1 compared to HDCs or HCs. Conversely, the SPM LXA4 was significantly downregulated in AH patients. Some of these altered LMs were found to correlate with AH disease severity and various inflammatory cytokines. Particularly, the LTB4/LXA4 ratio was substantially elevated in AH patients relative to HDCs and HCs. This altered ratio displayed a positive correlation with the MELD score. Importantly, the majority of dysregulated LMs, particularly PLMs, were normalized following alcohol abstinence.

Dietary Intake of Chromista Oil Alters Hepatic Metabolomic Profile of Mice With Excess Fat Mass

Increasing dietary intake of fish oil is frequently recommended for decreasing the risk for cardiovascular diseases and improving metabolic health. We hypothesised that dietary intake of chromista oil (a marine food product and a rich source of long-chain n-3 polyunsaturated fatty acids) ameliorates metabolic impairments in mice with established excess adiposity. Three-to 4-week-old mice (male) were fed a control (n = 12) or a high-fat diet (HFD, n = 24) for 12 weeks to establish body fat mass. Then, mice on the HFD were assigned to 2 groups (n = 12 each) with 1 continuing being fed the HFD and the other fed the HFD with chromista oil for an additional 12 weeks. Intake of chromista oil did not affect body weight and body adiposity of the mice fed the HFD; mice fed the HFD had significantly more body weight and fat mass than control mice. The flattened daily oscillations of respiratory exchange ratio induced by the HFD were not changed by chromista oil intake. Intake of chromista oil significantly increased plasma concentration of insulin, the calculated value of HOMA-IR, and plasma concentration of adiponectin in the mice fed the HFD. However, blood glucose was unaffected by chromista oil. Transcription of genes encoding circadian rhythm and fatty acid metabolism of the 2 HFD-fed groups were similar. Untargeted metabolomic analysis showed that intake of chromista oil altered the hepatic metabolomic profile with substantial alterations in amino acid metabolism. Findings from this study indicate that dietary intake of chromista oil does not improve glucose homeostasis or alter the diminished metabolic flexibility in mice with excess adiposity induced by the HFD. argeted metabolomic analysis is warranted to investigate the effects of dietary chromista oil, as a source of n-3 poly unsaturated fatty acids, on metabolism in models of obesity.

Gut microbiota: Implications in pathogenesis and therapy to cardiovascular disease (Review)

The gut microbiota refers to the diverse bacterial community residing in the gastrointestinal tract. Recent data indicate a strong correlation between alterations in the gut microbiota composition and the onset of various diseases, notably cardiovascular disorders. Evidence suggests the gut-cardiovascular axis signaling molecules released by the gut microbiota play a pivotal role in regulation. This review systematically delineates the association between dysbiosis of the gut microbiota and prevalent cardiovascular diseases, including atherosclerosis, hypertension, myocardial infarction and heart failure. Furthermore, it provides an overview of the putative pathogenic mechanisms by which dysbiosis in the gut microbiota contributes to the progression of cardiovascular ailments. The potential modulation of gut microbiota as a preventive strategy against cardiovascular diseases through dietary interventions, antibiotic therapies and probiotic supplementation is also explored and discussed within the present study.

Gymnemic acid alleviates gut barrier disruption and lipid dysmetabolism via regulating gut microbiota in HFD hamsters

Gut microbiota dysbiosis and gut barrier disruption are key events associated with high-fat diet (HFD)-induced systemic metabolic disorders. Gymnemic acid (GA) has been reported to have an important role in alleviating HFD-induced disorders of glycolipid metabolism, but its regulatory role in HFD-induced disorders of the gut microbiota and gut barrier function has not been elucidated. Here we showed that GA intervention in HFD-induced hamsters increased the relative abundance of short-chain fatty acid (SCFA)-producing microbes including Lactobacillus (P<.05) and Lachnoclostridium (P<.01) in the gut, and reduced the relative abundance of lipopolysaccharide (LPS)-producing microbes including Enterococcus (P<.05) and Bacteroides (P<.05), subsequently improving HFD-induced intestinal barrier dysfunction and systemic inflammation. Specifically, GA intervention reduced mRNA expression of inflammatory cytokines, including IL-1β, IL-6, and TNF-α (P<.01), increased mRNA expression of antioxidant-related genes, including Nfe2l2, Ho-1, and Nqo1 (P<.01), and increased mRNA expression of intestinal tight junction proteins, including Occludin and Claudin-1 (P<.01), thereby improving gut barrier function of HFD hamsters. This ameliorative effect of GA on the gut of HFD hamsters may further promote lipid metabolic balance in liver and adipose tissue by regulating the Toll-like receptor 4 (TLR4)-nuclear factor-κB (NF-κB) signaling pathway. Taken together, these results systematically revealed the important role of GA in regulating HFD-induced gut microbiota disturbance and gut barrier function impairment, providing a potential clinical theoretical basis for targeted treatment of HFD-induced microbiota dysbiosis.

Gut barrier dysfunction, endotoxemia and inflammatory response in STEMI patients and effect of primary PCI

BACKGROUND

Gut-derived bacterial and endotoxin translocation induce systemic inflammation, which exerts a pivotal pathogenetic role in all phases of atherosclerosis.

OBJECTIVES

To investigate prospectively the gut barrier function, endotoxin translocation and inflammatory response in ST-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary artery intervention (PPCI).

METHODS

Twenty-seven patients with STEMI that underwent successful PPCI were subjected to peripheral blood sampling at 3-time points; before PPCI (day0), 24 h (day1) and 96 h (day4) after PPCI and were compared with 20 chronic coronary syndrome (CCS) patients and 11 healthy controls. Serum ZO-1, I-FABP and endotoxin concentrations were determined by ELISA. Concentrations of cytokines IL-1β, -6, -8, -10 and TNF-α were determined by flow cytometry.

RESULTS

Patients with STEMI before PPCI (day0) had increased serum ZO-1 and endotoxin, both at significantly higher levels compared to CCS patients. STEMI induced also significant increases of the cytokines IL-6, -8 and -10. After PPCI, a significant improvement of gut barrier integrity (ZO-1) and endotoxemia was observed from the first day. At day4 post PPCI, systemic endotoxin and cytokines IL-6, -8 and -10 levels were reduced to control levels. Serum ZO-1 levels were positively correlated with systemic IL-10 concentrations (r = 0.471).

CONCLUSION

STEMI is associated with gut barrier dysfunction, systemic endotoxemia and inflammatory response, which improve rapidly following successful PPCI.

Dietary soy protein reverses obesity-induced liver steatosis and alters fecal microbial composition independent of isoflavone level

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health concern that is exacerbated by the obesity pandemic. Dietary interventions have the potential to alleviate obesity-associated MASLD through variable mechanisms, including optimizing the gut microbiota. Previously, we reported that soy protein concentrate (SPC) with low or high levels of isoflavone (LIF or HIF) protected young obese Zucker rats from developing liver steatosis. The current study was designed to test whether SPC-LIF and SPC-HIF diets would reverse liver steatosis and alter fecal microbial composition in adult obese Zucker rats with existing steatosis.

Methods

Six-week-old male obese Zucker rats (n = 26) were fed a casein control diet (CAS) for 8 weeks and 7 rats were randomly selected and sacrificed to confirm liver steatosis. The remaining rats were randomly assigned to receive CAS, SPC-LIF, or SPC-HIF diet (n = 6-7/group) for an additional 10 weeks.

Results

Compared to CAS diet, feeding SPC-LIF and SPC-HIF diets resulted in significantly lower liver weight, liver steatosis score, and liver microvesicular score (p < 0.05), but did not lead to difference in body weight, liver macrovesicular score, serum ALT, or serum AST. Isoflavone levels (e.g., LIF vs. HIF) did not affect any of these measurements except in the SPC-HIF group, which had an additional decrease in liver weight (p < 0.05) compared to the SPC-LIF group. The SPC-HIF group also had significantly higher levels of the aglycone forms of daidzein, genistein, and equol as well as the total levels of daidzein, genistein, and equol compared to SPC-LIF or CAS diet fed rats (p < 0.05). The distribution of microbial communities based on measures of beta diversity of both SPC-LIF and SPC-HIF groups were significantly different to that of the CAS group (p ≤ 0.005). Alpha-diversity did not differ between any of the groups.

Conclusion

Taken together, dietary soy protein can reverse liver steatosis in adult Zucker rats, and the reversal of steatosis is accompanied by alterations in gut microbial composition.

Alterations in the Gut Microbiota Composition in Obesity with and without Type 2 Diabetes: A Pilot Study

Purpose

Obesity has become a major public health concern worldwide, increasing the risk of T2DM. Growing evidence indicates gut microbiota dysbiosis is related to metabolic disorders. We aimed to firstly investigate the compositional and functional features of the gut microbiome between obesity with and without T2DM in the Chinese population.

Methods

A total of 32 obese individuals accompanied with T2DM and 18 age and gender-matched obesity with normal glucose tolerance (NGT) were enrolled. Fecal samples were collected, and the gut microbiota profile was determined using the Illumina MiSeq platform based on V3-V4 bacterial 16S rRNA gene.

Results

Compared with obesity- NGT, obesity-T2DM showed a significantly higher alpha diversity. Principal coordinates analysis based on both Bray-Curtis distance and weighted Unifrac revealed that the global microbial composition was significantly different between the two groups (P = 0.007 and P = 0.005, respectively). At the phylum level, Obesity-T2DM patients exhibited a significant decrease in Bacteroidetes, and a pronounced increase in Firmicutes. Regarding the genus level, Bacteroides and Escherichia-Shigella were found to increase considerably, while Prevotella_9 and Sutterella had an evident decrease in Obesity-T2DM. Furthermore, Spearman correlation analysis revealed that Prevotella_9 and Sutterella were negatively associated with HbA1c and fasting blood glucose.

Conclusion

We found clear differences in the gut microbiota composition in obesity-T2DM compared with obesity-NGT. Obesity accompanied with T2DM may aggravate the obesity-associated gut microbiota, and gut microbiota is expected to be a promising novel intervention target for obese management. However, larger sample size and more in-depth taxonomic identification studies are warranted.