Leaky Gut: Effect of Dietary Fiber and Fats on Microbiome and Intestinal Barrier

Multifunctional dietary approach reduces intestinal inflammation in relation with changes in gut microbiota composition in subjects at cardiometabolic risk: the SINFONI project

The development of cardiometabolic (CM) diseases is associated with chronic low-grade inflammation, partly linked to alterations of the gut microbiota (GM) and reduced intestinal integrity. The SINFONI project investigates a multifunctional (MF) nutritional strategy's impact combining different bioactive compounds on inflammation, GM modulation and CM profile. In this randomized crossover-controlled study, 30 subjects at CM-risk consumed MF cereal-products, enriched with polyphenols, fibers, slowly-digestible starch, omega-3 fatty acids or Control cereal-products (without bioactive compounds) for 2 months. Metabolic endotoxemia (lipopolysaccharide (LPS), lipopolysaccharide-binding protein over soluble cluster of differentiation-14 (LBP/sCD14), systemic inflammation and cardiovascular risk markers, intestinal inflammation, CM profile and response to a one-week fructose supplementation, were assessed at fasting and post mixed-meal. GM composition and metabolomic analysis were conducted. Mixed linear models were employed, integrating time (pre/post), treatment (MF/control), and sequence/period. Compared to control, MF intervention reduced intestinal inflammation (fecal calprotectin, p = 0.007) and endotoxemia (fasting LPS, p < 0.05), without alteration of systemic inflammation. MF decreased serum branched-chain amino acids compared to control (p < 0.05) and increased B.ovatus, B.uniformis, A.butyriciproducens and unclassified Christensenellaceae.CAG-74 (p < 0.05). CM markers were unchanged. A 2-month dietary intervention combining multiple bioactive compounds improved intestinal inflammation and induced GM modulation. Such strategy appears as an effective strategy to target low-grade inflammation through multi-target approach.

Adiposity and inflammation markers explain mostly part of the plasma zonulin variation in Brazilian adults with overweight/obesity: A cross-sectional analysis from Brazilian nuts study

OBJECTIVE

This study evaluated intestinal permeability according to plasma zonulin and its association with adiposity, inflammation, cardiometabolic risk, liver function, and intestinal health markers in adults with overweight/obesity.

METHODOLOGY

This study is a cross-sectional analysis using baseline data from the Brazilian Nut Study, which involved 123 participants (93 women, age 33.2 ± 8.58 years, BMI 33.9 ± 4.30kg/m2). Subjects were divided into quartiles according to plasma zonulin, assessed by Elisa. Cytokines were assessed by flow cytometry; anthropometric measurements were collected by standard procedure and body composition was assessed by DXA. SCFA analysis was performed by high-performance liquid chromatography, and fecal pH, by a pH meter. Linear regression models were performed (α<5 %).

RESULTS

Participants included in the last quartile of plasma zonulin had higher values of body fat (%), pro-inflammatory cytokines (CRP, IL-1). According to the multivariate regression model, each one-unit increased in body fat, CRP, IL-12p70, IL-6 and IL-8 resulted correspondingly in an increment of 0.42, 0.14, 0.192, 0.250 and 0.312 ng/ml in plasma zonulin, respectively. Conversely, a one-unit decreased in IL-10 led to an increase of 0.40 ng/ml in plasma zonulin.

CONCLUSION

Intestinal permeability assessed by plasma zonulin is associated with adiposity, subclinical inflammation and reduced serum HDL levels adults with overweight/obesity, while adiposity and inflammation markers are independent factors for plasma zonulin variation.

The moderating effect of dietary fiber intake on the association between sleep pattern and liver fibrosis in metabolic dysfunction-associated steatotic liver disease: a study from NHANES

BACKGROUND

Insufficient nocturnal sleep was associated with a higher risk of fibrosis in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). Dietary fiber intake may improve the stimulate the secretion of sleep cytokines, inhibit the inflammatory pathway, contribute to regulating sleep disorders and alleviate liver fibrosis. The associations of dietary fiber intake, sleep patterns, with liver fibrosis remain unclear. The study aimed to explore the associations between dietary fiber, sleep, and liver fibrosis, as well as the moderating effect of dietary fiber intake between sleep patterns and liver fibrosis in MASLD patients.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) database spanning from 2017 to 2020, a cross-sectional study included participants with MASLD was performed to assess the relationship between sleep patterns, dietary fiber intake, and liver fibrosis. Weighted univariate and multivariate logistic regression models were used to examine the linear connection between sleep pattern, dietary fiber intake, and liver fibrosis. Restricted cubic spline (RCS) method was also performed to describe the nonlinear relationship. A two-part linear regression model was also used to estimate threshold effects. The moderating effect of dietary fiber intake was further investigated in different subgroups. All results were presented as odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Totally, 1343 MASLD patients were included for final analysis. Among them, 207 (15.41%) have liver fibrosis. Dietary fiber intake did not correlate significantly with sleep pattern in patients with MASLD (Spearman's r = -0.028, P = 0.1678). Poor sleep pattern was related to higher odds of liver fibrosis (OR = 3.23, 95%CI: 1.05-9.90), while dietary fiber intake ≥ 15 gm/day was associated with lower liver fibrosis risk (OR = 0.51, 95%CI: 0.32-0.83). On the association between sleep pattern and liver fibrosis stratified by dietary fiber intake revealed that poor sleep patterns (OR = 15.13, 95%CI: 4.40-52.01) remained associated with increased liver fibrosis risk among individuals with dietary fiber intake < 15 gm/day. No connection was observed between poor sleep patterns and liver fibrosis in MASLD patients with higher dietary fiber intake, with moderate dietary fiber supplementation beneficial in mitigating poor sleep patterns associated with liver fibrosis. The similar findings were also found in patients aged < 50 years old, ≥ 50 years old, females, those with and without CVD groups, hypertension, and dyslipidemia. Particularly, dietary fiber intake also moderates the relationship between sleep patterns and liver fibrosis in the F4 stage (OR = 13.26, 95%CI: 4.08-43.11).

CONCLUSION

Dietary fiber intake affects the relationship between sleep patterns and liver fibrosis in MASLD patients.

A low-dose prebiotic fiber supplement reduces lipopolysaccharide-binding protein concentrations in a subgroup of young, healthy adults consuming low-fiber diets

Although the beneficial effects of fiber supplementation on overall health and the gut microbiome are well-known, it is not clear whether fiber supplementation can also alter the concentrations of lipopolysaccharide-binding protein (LBP), a marker of intestinal permeability. A secondary analysis of a previously conducted study was performed. In the randomized-order, placebo-controlled, double-blinded, cross-over study 20 healthy, young participants consuming a low-fiber diet at baseline were administered a daily dose of 12 g of prebiotic fiber compared with a placebo over a period of 4 weeks with a 4-week washout between arms. In this secondary analysis, we hypothesized that the fiber supplement would reduce LBP concentration. We further hypothesized that lecithin cholesterol acyltransferase activity, a measure of high-density lipoprotein functional capacity, would be altered. Fiber supplementation did not significantly alter LBP concentration or lecithin cholesterol acyltransferase activity in the overall cohort. However, in a subgroup of individuals with elevated baseline LBP concentrations, fiber supplementation significantly reduced LBP from 9.27 ± 3.52 to 7.02 ± 2.32 µg/mL (P = .003). Exploratory analyses found positive correlations between microbial genes involved in lipopolysaccharide synthesis and conversely negative correlations with genes involved in antibiotic synthesis and LBP. Positive correlations between LBP and multiple sulfated molecules including sulfated bile acids and perfluorooctanesulfonate, and ibuprofen metabolites were also found. These findings highlight multiple environmental and lifestyle factors such as exposure to industrial chemicals and medication intake, in addition to diet, which may influence the association between the gut microbiome and gut barrier function.

Leaky gut in systemic inflammation: exploring the link between gastrointestinal disorders and age-related diseases

Global average life expectancy has steadily increased over the last several decades and is projected to reach ~ 77 years by 2050. As it stands, the number of people > 60 years currently outnumbers children younger than 5 years, and by 2050, it is anticipated that the global population of people aged > 60 years will double, surpassing 2.1 billion. This demographic shift in our population is expected to have substantial consequences on health services globally due to the disease burden associated with aging. Osteoarthritis, chronic obstructive pulmonary disease, diabetes, cardiovascular disease, and cognitive decline associated with dementia are among the most common age-related diseases and contribute significantly to morbidity and mortality in the aged population. Many of these age-related diseases have been linked to chronic low-grade systemic inflammation which often accompanies aging. Gastrointestinal barrier dysfunction, also known as "leaky gut," has been shown to contribute to systemic inflammation in several diseases including inflammatory bowel disease and irritable bowel syndrome, but its role in the development and/or progression of chronic low-grade systemic inflammation during aging is unclear. This review outlines current literature on the leaky gut in aging, how leaky gut might contribute to systemic inflammation, and the links between gastrointestinal inflammatory diseases and common age-related diseases to provide insight into a potential relationship between the intestinal barrier and inflammation.

Cryptosporidium parvum infection alters the intestinal mucosa transcriptome in neonatal calves: impacts on epithelial barriers and transcellular transport systems

Introduction

Cryptosporidium parvum (C. parvum) is the most prevalent enteric protozoan parasite causing infectious diarrhea in neonatal calves worldwide with a direct negative impact on their health and welfare. This study utilized next-generation sequencing (NGS) to deepen our understanding of intestinal epithelial barriers and transport mechanisms in the pathophysiology of infectious diarrhea in neonatal calves, which could potentially unveil novel solutions for treatment.

Methods

At day 1 of life, male Holstein-Friesian calves were either orally infected (n = 5) or not (control group, n = 5) with C. parvum oocysts (in-house strain LE-01-Cp-15). On day 8 after infection, calves were slaughtered and jejunum mucosa samples were taken. The RNA was extracted from collected samples and subjected to sequencing. Differentially expressed genes (DEG) between the infected and CTRL groups were assessed using DESeq2 at a false discovery rate < 0.05 and used for gene ontology (GO) and pathway enrichment analysis in Cytoscape (v3.9.1).

Results and discussion

To study the pathophysiology of infectious diarrhea on intestinal permeability, 459 genes related to epithelial cell barrier integrity and paracellular and transmembrane transport systems were selected from 12,908 identified genes in mucus. Among, there were 61 increased and 109 decreased gene transcripts belonged to adhesion molecules (e.g. ADGRD1 and VCAM1), ATP-binding cassette (ABC, e.g. ABCC2 and ABCD1) and solute carrier (SLC, e.g. SLC28A2 and SLC38A3) transporters, and ion channels (e.g. KCNJ15). Our results suggest deregulation of cellular junctions and thus a possibly increased intestinal permeability, whereas deregulation of ABC and SLC transporters and ion channels may influence the absorption/secretion of amino acids, carbohydrates, fats, and organic compounds, as well as acid-based balance and osmotic hemostasis. Besides pathogen-induced gene expression alterations, part of the DEG may have been triggered or consequently affected by inflammatory mechanisms. The study provided a deeper understanding of the pathophysiology of infectious diarrhea in neonatal calves and the host-pathogen interactions at the transcript level. For further studies with a particular focus on the transport system, these results could lead to a new approach to elucidating pathophysiological regulatory mechanisms.

Lactobacillus fermentum MCC2760 Attenuates Heated Oil-Induced Brain Oxidative Stress and Inflammation via Modulation of NRF2 and NF-kB in Rats

SCOPE

Reusing deep-fried oil is a common practice to cut costs, and their consumption may affect brain function. Hence, the study investigates the modulatory potential of Lactobacillus fermentum MCC2760 (LF) on heated oil-induced brain oxidative stress (OS) and inflammation that may have a bearing on cognition in experimental rats.

METHODS AND RESULTS

Female Wistar rats are fed with diets containing native sunflower oil (N-SFO), native canola oil (N-CNO), heated sunflower oil (H-SFO), heated canola oil (H-CNO), heated sunflower oil with probiotic (H-SFO + LF), or heated canola oil with probiotic (H-CNO + LF} for 60 days. Compared to respective controls, heated oils significantly (p < 0.05) increased OS by decreasing antioxidant defense enzymes and nuclear factor erythroid 2-related factor 2 (NRF2) activity. Further, heated oil elevates brain expression of cytosolic phospholipase A2 (cPLA2), cyclooxygenase-2 (COX-2), prostaglandin-E receptor 4 (EP-4), intercellular adhesion molecule 1 (ICAM-1), nitric oxide synthase 2 (NOS-2), followed by an increased production of proinflammatory eicosanoids (prostaglandin E2 [PGE2] and leukotriene B4 [LTB4]) and cytokines (tumor necrosis factor-α [TNF-α], monocyte chemoattractant protein-1 [MCP-1], interleukin-1β [IL-1β], and interleukin-6 [IL-6]). The increased nuclear translocation of nuclear factor kappa beta (NF-kB) in heated oil-fed groups' brains corroborates the heightened inflammatory response. Heated oils decrease neurotrophins and neuron development markers. However, administration of LF abrogates the heated oil-induced alterations significantly (p < 0.05).

CONCLUSIONS

The present study is novel in demonstrating the protective role of probiotic LF against heated-oil-induced brain OS and inflammation in rats.

Guardians of the Gut: Harnessing the Power of Probiotic Microbiota and Their Exopolysaccharides to Mitigate Heavy Metal Toxicity in Human for Better Health

Heavy metal pollution is a significant global health concern, posing risks to both the environment and human health. Exposure to heavy metals happens through various channels like contaminated water, food, air, and workplaces, resulting in severe health implications. Heavy metals also disrupt the gut's microbial balance, leading to dysbiosis characterized by a decrease in beneficial microorganisms and proliferation in harmful ones, ultimately exacerbating health problems. Probiotic microorganisms have demonstrated their ability to adsorb and sequester heavy metals, while their exopolysaccharides (EPS) exhibit chelating properties, aiding in mitigating heavy metal toxicity. These beneficial microorganisms aid in restoring gut integrity through processes like biosorption, bioaccumulation, and biotransformation of heavy metals. Incorporating probiotic strains with high affinity for heavy metals into functional foods and supplements presents a practical approach to mitigating heavy metal toxicity while enhancing gut health. Utilizing probiotic microbiota and their exopolysaccharides to address heavy metal toxicity offers a novel method for improving human health through modulation of the gut microbiome. By combining probiotics and exopolysaccharides, a distinctive strategy emerges for mitigating heavy metal toxicity, highlighting promising avenues for therapeutic interventions and health improvements. Further exploration in this domain could lead to groundbreaking therapies and preventive measures, underscoring probiotic microbiota and exopolysaccharides as natural and environmentally friendly solutions to heavy metal toxicity. This, in turn, could enhance public health by safeguarding the gut from environmental contaminants.

Dietary Nutrition: The Friend or the Foe to Gastrointestinal Health

Over the years and even centuries, instincts, habits, cultures, social determinants, wars, and health needs were, and still are, factors that have shaped our dietary nutrition [...].

Effect of Anacardium occidentale Leaf Powder on Growth Performance, Diarrhea Incidence, Blood Biochemistry, and Intestinal Traits in Weaned Piglets

To evaluate the phytobiotic effect of Anacardium occidentale leaf powder (AOLP) on growth performance, diarrhea incidence, blood biochemistry, and intestinal traits, seventy-two weaned piglets were randomly distributed into four groups (six replicates/group and three pigs/replicate) for 28 days, receiving a control diet (T0) or being supplemented with 5 (T1), 10 (T2), or 15 (T3) g/kg of AOLP. The diets did not affect the growth performance (p > 0.05); however, the AOLP groups had a decreased diarrhea incidence and malondialdehyde concentration (p < 0.05; 28 days). However, the AOLP groups had increased immunoglobulins (G and M) and villus heights (p < 0.05) in the duodenum. Likewise, T3 improved the number of goblet cells in the villi and the whole intestine (p < 0.01), the Mucin2 area in the jejunum and ileum (p < 0.05), occludin gene expression in the jejunum (p < 0.01), and acetic and valeric acid production (p < 0.05). Microbial diversity at the genus level was not different (p > 0.05); however, T3 increased the abundance of the Lactobacillus genus. These findings suggest that dietary supplementation with AOLP improved intestinal health by increasing antioxidant, immune, anti-inflammatory, and antidiarrheal activity in the weaned piglets.

The Hydrophobic Amino Acid-Rich Fish Collagen Peptide Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice via Repairing the Intestinal Barrier, Regulating Intestinal Flora and AA Metabolism

The incidence of ulcerative colitis (UC) is increasing annually, but treatment option is limited. Fish collagen peptide (FCP) is a food source collagen peptide that has shown promise in alleviating UC symptoms. However, its impact on the intestinal barrier and intestinal metabolic homeostasis in UC remains unclear. This study aimed to analyze the peptide sequences and absolute amino acid (AA) content of FCP, assessing its effects on UC in mice induced by dextran sulfate sodium (DSS). FCP was examined by liquid chromatography and tandem mass spectrometry (LC-MS/MS) analysis. The 3% DSS was utilized to induce UC in murine models, followed by the assessment of the therapeutic efficacy of FCP. Clinical manifestations of UC mice were meticulously evaluated and scored. Subsequently, samples were procured for histological examination and intestinal epithelial barrier integrity analysis as well as macrogenomic and metabolomic profiling. Here, it shows that abundant peptide sequences and AAs were in FCP, particularly enriched in hydrophobic AAs (HAAs). Furthermore, it was observed that FCP effectively reversed colon shortening and reduced the extent of histological damage. Additionally, FCP suppressed the abnormal expression of inflammatory factors and intestinal barrier proteins and modulated the dysbiosis of gut microbiota toward a balanced state. These alterations led to the activation of intestinal alkaline AA and various AA metabolisms, ultimately contributing to the mitigation of UC symptoms. In summary, the diverse peptide sequences and high AAs in FCP, particularly rich in HAAs, can alleviate DSS-induced UC via preserving intestinal barrier integrity, regulating gut microbiota, and modulating AA metabolism.

Managing Type 2 Diabetes Mellitus via the Regulation of Gut Microbiota: A Chinese Medicine Perspective

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder characterized by insulin resistance and inadequate insulin production. Given the increased frequency of T2DM and the health issues it can cause, there is an increasing need to develop alternative T2DM management strategies. One such approach is Chinese Medicine (CM), a complementary therapy widely used in T2DM treatment. Given the emphasis on gut microbiota in current research, studying CM in the treatment of T2DM via gut microbiota modulation could be beneficial. Scope and approach: The use of various CM methods for managing T2DM via gut microbiota modulation is highlighted in this review. Following an introduction of the gut microbiota and its role in T2DM pathogenesis, we will review the potential interactions between gut microbiota and T2DM. Thereafter, we will review various CM treatment modalities that modulate gut microbiota and provide perspectives for future research. Key findings and discussion: In T2DM, Akkermansia, Bifidobacterium, and Firmicutes are examples of gut microbiota commonly imbalanced. Studies have shown that CM therapies can modulate gut microbiota, leading to beneficial effects such as reduced inflammation, improved metabolism, and improved immunity. Among these treatment modalities, Chinese Herbal Medicine and acupuncture are the most well-studied, and several in vivo studies have demonstrated their potential in managing T2DM by modulating gut microbiota. However, the underlying biomolecular mechanisms of actions are not well elucidated, which is a key area for future research. Future studies could also investigate alternate CM therapies such as moxibustion and CM exercises and conduct large-scale clinical trials to validate their effectiveness in treatment.

Exosomes from Limosilactobacillus fermentum Ameliorate Benzalkonium Chloride-Induced Inflammation in Conjunctival Cells

Dry eye is characterized by persistent instability and decreased tear production, which are accompanied by epithelial lesions and inflammation on the surface of the eye. In our previous paper, we reported that supplementation with Limosilactobacillus fermentum HY7302 (HY7302) could inhibit corneal damage in a benzalkonium chloride (BAC)-induced mouse model of dry eye, through its effects in gut microbiome regulation. The aim of this study was to determine what functional extracellular substances can alter the inflammatory response of conjunctival cells. We isolated exosomes from HY7302 probiotic culture supernatant, analyzed their morphological characteristics, and found that their average size was 143.8 ± 1.1 nm, which was smaller than the exosomes from the L. fermentum KCTC 3112 strain. In addition, HY7302-derived exosomes significantly reduced the levels of genes encoding pro-inflammatory cytokines, including interleukin (IL)-20, IL-8, IL-6, and IL-1B, in BAC-treated human conjunctival cells. Moreover, HY7302-derived exosomes significantly increased the levels of genes encoding tight junction proteins, including TJP1, TJP2, and occludin-1, in Caco-2 cells. Lastly, the HY7302 exosomes reduced mRNA expression levels of IL1B, IL20, IL6, IL8, and NFAT5 in a transwell coculture system. Our findings indicate that HY7302 exosomes have potential for use in the treatment of ocular inflammation-related dry eye disease, through gut-eye axis communication via exosomes.

A review of the pathogenesis of epilepsy based on the microbiota-gut-brain-axis theory

The pathogenesis of epilepsy is related to the microbiota-gut-brain axis, but the mechanism has not been clarified. The microbiota-gut-brain axis is divided into the microbiota-gut-brain axis (upward pathways) and the brain-gut-microbiota axis (downward pathways) according to the direction of conduction. Gut microorganisms are involved in pathological and physiological processes in the human body and participate in epileptogenesis through neurological, immunological, endocrine, and metabolic pathways, as well as through the gut barrier and blood brain barrier mediated upward pathways. After epilepsy, the downward pathway mediated by the HPA axis and autonomic nerves triggers "leaky brain "and "leaky gut," resulting in the formation of microbial structures and enterobacterial metabolites associated with epileptogenicity, re-initiating seizures via the upward pathway. Characteristic changes in microbial and metabolic pathways in the gut of epileptic patients provide new targets for clinical prevention and treatment of epilepsy through the upward pathway. Based on these changes, this review further redescribes the pathogenesis of epilepsy and provides a new direction for its prevention and treatment.

The effect of dietary emulsifiers and thickeners on intestinal barrier function and its response to acute stress in healthy adult humans: A randomised controlled feeding study

BACKGROUND

Although dietary emulsifiers are implicated in the pathogenesis of Crohn's disease, their effect has not been studied in humans.

AIM

To determine the effects of high- and low-emulsifier diets (HED, LED) on intestinal barrier function in healthy subjects in unstressed and acutely stressed states.

METHODS

We conducted a single-blinded, cross-over, controlled feeding trial in 22 healthy adults. After recording 7 days of their habitual diet, we randomised participants to HED or LED with ≥3-week washout between diets. On dietary completion, acute stress was induced via intravenous corticotrophin-releasing hormone. We assessed dietary adherence, effects on 2-h urinary lactulose: rhamnose ratio (LRR), serum concentrations of lipopolysaccharide-binding protein, soluble-CD14 and markers of epithelial injury and inflammation.

RESULTS

Dietary adherence was excellent. In an unstressed state, median (interquartile range) LRR during HED was 0.030 (0.018-0.042); on LED, this was 0.042 (0.029-0.078; p = 0.04). LPB concentrations were lower on HED than LED (p = 0.026), but no differences were observed for epithelial injury or inflammation. Under acute stress, LRR increased by 89% (-1% to 486%) on HED (p = 0.004), differing (p = 0.001) from 39% (1%-90%) decrease on LED (p = 0.009). Soluble-CD14 also increased (p < 0.001). The LED had a prolonged carry-over effect on suppressing HED-induced changes during stress. Similar changes in LRR and soluble-CD14 were observed when HED was used as the first diet (both p < 0.01).

CONCLUSION

High intake of emulsifiers improved barrier function in the unstressed state, but increased intestinal permeability to stress, without evidence of inflammation. A LED was protective of the stress effect.

Opening the doors of precision medicine: novel tools to assess intestinal barrier in inflammatory bowel disease and colitis-associated neoplasia

Mounting evidence underscores the pivotal role of the intestinal barrier and its convoluted network with diet and intestinal microbiome in the pathogenesis of inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CRC). Moreover, the bidirectional association of the intestinal barrier with the liver and brain, known as the gut-brain axis, plays a crucial role in developing complications, including extraintestinal manifestations of IBD and CRC metastasis. Consequently, barrier healing represents a crucial therapeutic target in these inflammatory-dependent disorders, with barrier assessment predicting disease outcomes, response to therapy and extraintestinal manifestations.New advanced technologies are revolutionising our understanding of the barrier paradigm, enabling the accurate assessment of the intestinal barrier and aiding in unravelling the complexity of the gut-brain axis. Cutting-edge endoscopic imaging techniques, such as ultra-high magnification endocytoscopy and probe-based confocal laser endomicroscopy, are new technologies allowing real-time exploration of the 'cellular' intestinal barrier. Additionally, novel advanced spatial imaging technology platforms, including multispectral imaging, upconversion nanoparticles, digital spatial profiling, optical spectroscopy and mass cytometry, enable a deep and comprehensive assessment of the 'molecular' and 'ultrastructural' barrier. In this promising landscape, artificial intelligence plays a pivotal role in standardising and integrating these novel tools, thereby contributing to barrier assessment and prediction of outcomes.Looking ahead, this integrated and comprehensive approach holds the promise of uncovering new therapeutic targets, breaking the therapeutic ceiling in IBD. Novel molecules, dietary interventions and microbiome modulation strategies aim to restore, reinforce, or modulate the gut-brain axis. These advancements have the potential for transformative and personalised approaches to managing IBD.

Alginate oligosaccharide supplementation improves boar semen quality under heat stress

Heat stress is a serious problem that affects animal husbandry by reducing growth and reproductive performance of animals. Adding plant extracts to the diet is an effective way to help overcome this problem. Alginate oligosaccharide (AOS) is a natural non-toxic antioxidant with multiple biological activities. This study analyzed the potential mechanism of AOS in alleviating heat stress and improving semen quality in boars through a combination of multiple omics tools. The results indicated that AOS could significantly increase sperm motility (P < 0.001) and sperm concentration (P < 0.05). At the same time, AOS improved the antioxidant capacity of blood and semen, and increased blood testosterone (P < 0.05) level. AOS could improve the metabolites in sperm, change the composition of gut microbiota, increase the relative abundance of beneficial bacteria such as Pseudomonas (P < 0.01), Escherichia-Shigella (P < 0.05), Bifidobacterium (P < 0.01), reduce the relative abundance of harmful bacteria such as Prevotella_9 (P < 0.05), Prevotellaceae_UCG-001 (P < 0.01), and increase the content of short chain fatty acids. Proteomic results showed that AOS increased proteins related to spermatogenesis, while decreasing heat shock protein 70 (P < 0.05) and heat shock protein 90 (P < 0.01). These results were verified using immunofluorescence staining technology. There was a good correlation among sperm quality, sperm metabolome, sperm proteome, and gut microbiota. In conclusion, AOS can be used as a feed additive to increase the semen quality of boars to enhance reproductive performance under heat stress.

Exploring the Long-Term Effect of Artificial Sweeteners on Metabolic Health

Artificial sweeteners (ASs) are widely used as low-calorie sugar substitutes for managing conditions like diabetes and obesity, but recent evidence suggests their health effects may be more complex than previously understood. High consumption has been associated with increased risks of metabolic disorders, cardiovascular diseases, certain cancers, and, somewhat paradoxically, weight gain, adverse pregnancy outcomes, and potential risks for individuals with low seizure thresholds. Studies, including the Women's Health Initiative, have linked artificially sweetened beverages to an elevated risk of stroke, coronary heart disease, and mortality, independent of established risk factors. Concerns extend to gut health, where ASs like saccharin have been linked to inflammatory bowel diseases, gut microbiota disruption, increased intestinal permeability, and dysbiosis, leading to metabolic disturbances such as impaired glucose tolerance, insulin resistance, and heightened systemic inflammation. These disruptions reduce the production of short-chain fatty acids crucial for insulin sensitivity, further contributing to the development of metabolic disorders like type 2 diabetes mellitus. Given these potential health risks, this review underscores the need for cautious use, informed consumer choices, and stringent regulatory oversight, while emphasizing the necessity for further research to elucidate long-term health effects and develop strategies to mitigate these risks.

The hypoglycemic effect of enzymatic modified dietary fiber from bamboo shoot on type 2 diabetes rats

Bamboo shoot is a healthy food rich in dietary fiber (DF). However, its highly insoluble DF and fibrous texture limit its application in industrially processed foods. To achieve industrial processing of bamboo shoot, cellulase was used to improve the physical characteristics of bamboo shoot DF in this study. After enzymatic hydrolysis, the content of soluble DF (SDF) of bamboo shoot increased by 99.28% (from 5.53% to 11.02%) significantly (p < 0.01). At the same time, the effect of enzymatic-modified bamboo SDF (EMBSDF) on streptozotocin-induced type 2 diabetes rats was explored. Results demonstrated that the high dose of EMBSDF (312.8 mg/kg) treated rats showed significant improvements in terms of glucose tolerance and insulin sensitivity (p < 0.01) compared with the diabetes rats. Meantime, it was observed that the levels of glucagon-like peptide-1, adiponectin and interleukin-4 of high dose of EMBSDF compared with diabetes rats were increased (p < 0.01) by 57.79%, 159.13%, and 6.17%, respectively. The tumor necrosis factor-α, C-reactive protein, and leptin levels were decreased (p < 0.01) by 62.89%, 31.53%, and 7.84%, respectively. Furthermore, apparent kidney and pancreas histology improvements were found in high-dose and mid-dose EMBSDF-treated diabetes rats. These results indicated that the modified DF significantly improved diabetes.

2', 3', 5'-tri-O-acetyl-N6-(3-hydroxyphenyl) adenosine alleviates diet-induced hyperlipidemia by modulating intestinal gene expression profiles and metabolic pathway

There is a growing body of evidence suggesting that the composition of intestinal flora plays a significant role in regulating lipid metabolism. 2', 3', 5'-tri-O-acetyl-N6-(3-hydroxyphenyl) adenosine (IMMH007) is a new candidate compound for regulating blood cholesterol and other lipids. In this study, we conducted metagenomic and metabolomic analyses on samples from high-fat diet-fed (HFD) hamsters treated with IMMH007. Our findings revealed that IMM-H007 reversed the imbalance of gut microbiota caused by a high-fat diet. Additionally, it activated adiponectin receptor and pantothenate and CoA biosynthesis pathway-related genes, which are known to regulate lipid and glucose metabolism. Furthermore, IMM-H007 promotes cholesterol metabolism by reducing the abundance of genes and species associated with 7α-dehydroxylation and bile salt hydrolase (BSH). Metabolomics and pharmacological studies have shown that IMM-H007 effectively improved glucose and lipid metabolism disorders caused by HFD, reduced the aggregation of secondary bile acids (SBAs), significantly increased the content of hyodeoxycholic acid (HDCA), and also activated the expression of VDR in the small intestine. As a result, there was a reduction in the leakage of diamine oxidase (DAO) into the bloodstream in hamsters, accompanied by an upregulation of ZO-1 expression in the small intestine. The results suggested that IMM-H007 regulated glucose and lipid metabolism, promoted cholesterol metabolism through activating the expression of VDR, inhibiting inflammatory and improving the permeability of the intestinal barrier. Thus, our study provides new understanding of how IMM-H007 interacts with intestinal function, microbiota, and relevant targets, shedding light on its mechanism of action.

Modulation of gut microbiota on intestinal permeability: A novel strategy for treating gastrointestinal related diseases

Accumulating evidence emphasizes the critical reciprocity between gut microbiota and intestinal barrier function in maintaining the gastrointestinal homeostasis. Given the fundamental role caused by intestinal permeability, which has been scrutinized as a measurable potential indicator of perturbed barrier function in clinical researches, it seems not surprising that recent decades have been marked by augmented efforts to determine the interaction between intestinal microbes and permeability of the individual. However, despite the significant progress in characterizing intestinal permeability and the commensal bacteria in the intestine, the mechanisms involved are still far from being thoroughly revealed. In the present review, based on multiomic methods, high-throughput sequencing and molecular biology techniques, the impacts of gut microbiota on intestinal permeability as well as their complex interaction networks are systematically summarized. Furthermore, the diseases related to intestinal permeability and main causes of changes in intestinal permeability are briefly introduced. The purpose of this review is to provide a novel prospection to elucidate the correlation between intestinal microbiota and permeability, and to explore a promising solution for diagnosis and treatment of gastrointestinal related diseases.

Possible immune mechanisms of gut microbiota and its metabolites in the occurrence and development of immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by increased platelet destruction and impaired production, leading to an elevated bleeding tendency. Recent studies have demonstrated an important link between the gut microbiota and the onset and progression of several immune diseases in humans, emphasizing that gut microbiota-derived metabolites play a non-negligible role in autoimmune diseases. The gut microbiota and its metabolites, such as short-chain fatty acids, oxidized trimethylamine, tryptophan metabolites, secondary bile acids and lipopolysaccharides, can alter intestinal barrier permeability by modulating immune cell differentiation and cytokine secretion, which in turn affects the systemic immune function of the host. It is therefore reasonable to hypothesize that ecological dysregulation of the gut microbiota may be an entirely new factor in the triggering of ITP. This article reviews the potential immune-related mechanisms of the gut microbiota and representative metabolites in ITP, as well as the important influence of leaky gut on the development of ITP, with a view to enriching the theoretical system of ITP-related gut microecology and providing new ideas for the study of ITP.

Deciphering the complex interplay of obesity, epithelial barrier dysfunction, and tight junction remodeling: Unraveling potential therapeutic avenues

Obesity stands as a formidable global health challenge, predisposing individuals to a plethora of chronic illnesses such as cardiovascular disease, diabetes, and cancer. A confluence of genetic polymorphisms, suboptimal dietary choices, and sedentary lifestyles significantly contribute to the elevated incidence of obesity. This multifaceted health issue profoundly disrupts homeostatic equilibrium at both organismal and cellular levels, with marked alterations in gut permeability as a salient consequence. The intricate mechanisms underlying these alterations have yet to be fully elucidated. Still, evidence suggests that heightened inflammatory cytokine levels and the remodeling of tight junction (TJ) proteins, particularly claudins, play a pivotal role in the manifestation of epithelial barrier dysfunction in obesity. Strategic targeting of proteins implicated in these pathways and metabolites such as short-chain fatty acids presents a promising intervention for restoring barrier functionality among individuals with obesity. Nonetheless, recognizing the heterogeneity among affected individuals is paramount; personalized medical interventions or dietary regimens tailored to specific genetic backgrounds and allergy profiles may prove indispensable. This comprehensive review delves into the nexus of obesity, tight junction remodeling, and barrier dysfunction, offering a critical appraisal of potential therapeutic interventions.

Blended-protein changes body weight gain and intestinal tissue morphology in rats by regulating arachidonic acid metabolism and secondary bile acid biosynthesis induced by gut microbiota

PURPOSE

The impact of dietary nutrients on body growth performance and the composition of gut microbes and metabolites is well-established. In this study, we aimed to determine whether dietary protein can regulate the physiological indexes and changes the intestinal tissue morphology in rats, and if dietary protein was a crucial regulatory factor for the composition, function, and metabolic pathways of the gut microbiota.

METHOD

A total of thirty male Sprague Dawley (SD) rats (inbred strain, weighted 110 ± 10 g) were randomly assigned to receive diets containing animal-based protein (whey protein, WP), plant-based protein (soybean protein, SP), or a blended protein (soybean-whey proteins, S-WP) for a duration of 8 weeks. To investigate the effects of various protein supplement sources on gut microbiota and metabolites, we performed a high throughput 16S rDNA sequencing association study and fecal metabolomics profiling on the SD rats. Additionally, we performed analyses of growth indexes, serum biochemical indexes, and intestinal morphology.

RESULTS

The rats in S-WP and WP group exhibited a significantly higher body weight and digestibility of dietary protein compared to the SP group (P < 0.05). The serum total protein content of rats in the WP and S-WP groups was significantly higher (P < 0.05) than that in SP group, and the SP group exhibited significantly lower (P < 0.05) serum blood glucose levels compared to the other two groups. The morphological data showed the rats in the S-WP group exhibited significantly longer villus height and shallower crypt depth (P < 0.05) than the SP group. The gut microbial diversity of the SP and S-WP groups exhibited a higher level than that of the WP group, and the microbiomes of the WP and S-WP groups are more similar compared to those of the SP group. The Arachidonic acid metabolism pathway is the most significant KEGG pathway when comparing the WP group and the SP group, as well as when comparing the SP group and the S-WP group.

CONCLUSION

The type of dietary proteins exerted a significant impact on the physiological indices of SD rats. Intake of S-WP diet can enhance energy provision, improve the body's digestion and absorption of nutrients, as well as promote intestinal tissue morphology. In addition, dietary protein plays a crucial role in modulating fecal metabolites by regulating the composition of the gut microbiota. Metabolomics analysis revealed that the changes in the levels of arachidonic acid metabolites and secondary bile acid metabolite induced by Clostridium_sensu_stricto_1 and [Eubacterium]_coprostanoligenes_group maybe the primarily causes of intestinal morphological differences.

Lactoferrin alleviates chronic low‑grade inflammation response in obese mice by regulating intestinal flora

Chronic low‑grade inflammation defines obesity as a metabolic disorder. Alterations in the structure of gut flora are strongly associated with obesity. Lactoferrin (LF) has a biological function in regulating intestinal flora. The present study aimed to investigate the therapeutic and anti‑-inflammatory effects of LF in obese mice based on intestinal flora. A total of 30 C57BL/6 mice were divided into three groups consisting of 10 mice each. Subsequently, one group was fed a normal diet (Group K), another group was fed a high‑fat diet (Group M) and the remaining group switched from regular drinking to drinking 2% LF water (Group Z2) after 2 weeks of high‑fat diet; all mice were fed for 12 weeks. After the experiment, the mouse blood lipid and lipopolysaccharide levels, levels of inflammatory factors and intestinal tight junction proteins were assessed. Mouse stool samples were analyzed using 16S ribosomal RNA sequencing. The results showed that LF reduced serum total cholesterol, triglycerides and low‑density lipoprotein levels, elevated high‑density lipoprotein levels, suppressed metabolic endotoxemia and attenuated chronic low‑grade inflammatory responses in obese mice. In addition, LF upregulated zonula occludens‑1 and occludin protein expression levels in the intestine, thereby improving intestinal barrier integrity. LF altered the intestinal microbial structure of obese mice, reduced the ratio of Firmicutes and an elevated ratio of Bacteroidota, modifying the bacterial population to the increased relative abundance of Alistipes, Acidobacteriota, Psychrobacter and Bryobacter.

Multistrain Probiotics with Fructooligosaccharides Improve Middle Cerebral Artery Occlusion-Driven Neurological Deficits by Revamping Microbiota-Gut-Brain Axis

Recent burgeoning literature unveils the importance of gut microbiota in the neuropathology of post-stroke brain injury and recovery. Indeed, ingestion of prebiotics/probiotics imparts positive effects on post-stroke brain injury, neuroinflammation, gut dysbiosis, and intestinal integrity. However, information on the disease-specific preference of selective prebiotics/probiotics/synbiotics and their underlying mechanism is yet elusive. Herein, we examined the effect of a new synbiotic formulation containing multistrain probiotics (Lactobacillus reuteri UBLRu-87, Lactobacillus plantarum UBLP-40, Lactobacillus rhamnosus UBLR-58, Lactobacillus salivarius UBLS-22, and Bifidobacterium breve UBBr-01), and prebiotic fructooligosaccharides using a middle cerebral artery occlusion (MCAO) model of cerebral ischemia in female and male rats. Three weeks pre-MCAO administration of synbiotic rescinded the MCAO-induced sensorimotor and motor deficits on day 3 post-stroke in rotarod, foot-fault, adhesive removal, and paw whisker test. We also observed a decrease in infarct volume and neuronal death in the ipsilateral hemisphere of synbiotic-treated MCAO rats. The synbiotic treatment also reversed the elevated levels/mRNA expression of the glial fibrillary acidic protein (GFAP), NeuN, IL-1β, TNF-α, IL-6, matrix metalloproteinase-9, and caspase-3 and decreased levels of occludin and zonula occludens-1 in MCAO rats. 16S rRNA gene-sequencing data of intestinal contents indicated an increase in genus/species of Prevotella (Prevotella copri), Lactobacillus (Lactobacillus reuteri), Roseburia, Allobaculum, and Faecalibacterium prausnitzii, and decreased abundance of Helicobacter, Desulfovibrio, and Akkermansia (Akkermansia muciniphila) in synbiotic-treated rats compared to the MCAO surgery group. These findings confer the potential benefits of our novel synbiotic preparation for MCAO-induced neurological dysfunctions by reshaping the gut-brain-axis mediators in rats.

The gut microbiome and dietary metabolites in the treatment of renal cell carcinoma

The gut microbiome is interlinked with renal cell carcinoma (RCC) and its response to systemic treatment. Mounting data suggests that certain elements of the gut microbiome may correlate with improved outcomes. New generation sequencing techniques and advanced bioinformatic data curation are accelerating the investigation of specific markers and metabolites that could predict treatment response. A variety of new therapeutic strategies, such as fecal microbiota transplantation, probiotic supplements, and dietary interventions, are currently being developed to modify the gut microbiome and improve anticancer therapies in patients with RCC. This review discusses the preliminary evidence indicating the role of the microbiome in cancer treatment, the techniques and tools necessary for its proper study and some of the current forms with which the microbiome can be modulated to improve patient outcomes.

Quercetin ameliorates bone loss in OVX rats by modulating the intestinal flora-SCFAs-inflammatory signaling axis

BACKGROUND

Osteoporosis (OP) is a common systemic skeletal disorder characterized by an imbalance in bone homeostasis, involving increased osteoclastic bone formation and decreased osteoblastic bone resorption. Quercetin is a plant polyphenol that has been found to exhibit various biological activities, including antioxidant, anti-inflammatory, and antimicrobial effects. Previous studies have demonstrated its potential to improve postmenopausal OP, although the exact mechanism remains unclear. This study aims to investigate the anti-osteoporotic mechanism of quercetin based on the "intestinal flora - short-chain fatty acids (SCFAs) - inflammatory" signaling axis.

METHODS

In this study, we established an ovariectomized (OVX)-induced rat model, quercetin intervention and evaluated the effects on rats following antibiotic (ABX) treatment and fecal microbiota transplantation (FMT). After 6 weeks of intervention, the rats were euthanized, and samples from their femur, tibia, lumbar spine, serum, colon and feces were collected, and bone strength, intestinal flora structure, SCFAs levels and cytokine levels were assessed.

RESULTS

Quercetin modulates the intestinal flora by increasing potentially probiotic bacteria (i.e., Lactobacillales, Prevotellaceae, and Blautia) and decreasing potentially pathogenic bacteria (Desulfobacterota, Erysipelotrichales, Romboutsia, and Butyricoccaceae). It also increases SCFAs content and reduces colonic permeability by enhancing tight junction proteins (ZO-1, Occludin). Furthermore, quercetin lowers proinflammatory cytokine levels (LPS, IL-1β, and TNF-α), which enhances bone strength and prevents OVX-induced bone loss.

CONCLUSIONS

Quercetin may effectively reduce bone loss in OVX rats via the "intestinal flora - SCFAs - inflammatory" signaling pathway.

The Leaky Gut and Human Diseases: "Can't Fill the Cup if You Don't Plug the Holes First"

BACKGROUND

The gut barrier is a sophisticated and dynamic system that forms the frontline defense between the external environment and the body's internal milieu and includes various structural and functional components engaged not only in digestion and nutrient absorption but also in immune regulation and overall health maintenance.

SUMMARY

When one or more components of the intestinal barrier lose their structure and escape their function, this may result in a leaky gut. Mounting evidence emphasizes the crucial role of the gut microbiome in preserving the integrity of the gut barrier and provides insights into the pathophysiological implications of conditions related to leaky gut in humans. Assessment of intestinal permeability has evolved from invasive techniques to noninvasive biomarkers, but challenges remain in achieving consensus about the best testing methods and their accuracy. Research on the modulation of gut permeability is just starting, and although no medical guidelines for the treatment of leaky gut syndrome are available, several treatment strategies are under investigation with promising results.

KEY MESSAGES

This review discusses the composition of the intestinal barrier, the pathophysiology of the leaky gut and its implications on human health, the measurement of intestinal permeability, and the therapeutic strategies to restore gut barrier integrity.

Intestinal barrier permeability: the influence of gut microbiota, nutrition, and exercise

The intestinal wall is a selectively permeable barrier between the content of the intestinal lumen and the internal environment of the body. Disturbances of intestinal wall permeability can potentially lead to unwanted activation of the enteric immune system due to excessive contact with gut microbiota and its components, and the development of endotoxemia, when the level of bacterial lipopolysaccharides increases in the blood, causing chronic low-intensity inflammation. In this review, the following aspects are covered: the structure of the intestinal wall barrier; the influence of the gut microbiota on the permeability of the intestinal wall via the regulation of functioning of tight junction proteins, synthesis/degradation of mucus and antioxidant effects; the molecular mechanisms of activation of the pro-inflammatory response caused by bacterial invasion through the TLR4-induced TIRAP/MyD88 and TRAM/TRIF signaling cascades; the influence of nutrition on intestinal permeability, and the influence of exercise with an emphasis on exercise-induced heat stress and hypoxia. Overall, this review provides some insight into how to prevent excessive intestinal barrier permeability and the associated inflammatory processes involved in many if not most pathologies. Some diets and physical exercise are supposed to be non-pharmacological approaches to maintain the integrity of intestinal barrier function and provide its efficient operation. However, at an early age, the increased intestinal permeability has a hormetic effect and contributes to the development of the immune system.

Recent advances in measuring the effects of diet on gastrointestinal physiology: Probing the "leaky gut" and application of real-time ultrasound

There is a large pool of ideas in both mainstream and non-mainstream medicine on how diet can be manipulated in order to treat or prevent illnesses. Despite this, our understanding of how specific changes in diet influence the structure and function of the gastrointestinal tract is limited. This review aims to describe two areas that might provide key information on the integrity and function of the gastrointestinal tract. First, demystifying the "leaky gut syndrome" requires rational application and interpretation of tests of intestinal barrier function. Multiple ways of measuring barrier function have been described, but the inherent difficulties in translation from animal studies to humans have created misinterpretations and misconceptions. The intrinsic nature of intestinal barrier function is dynamic. This is seldom considered in studies of intestinal barrier assessment. To adequately understand the effects of dietary interventions on intestinal barrier function, background barrier function in different regions of the gut and the dynamic responses to stressors (such as psychological stress) should be assessed as a minimum. Second, intestinal ultrasound, which is now established in the assessment and monitoring of inflammatory bowel disease, has hitherto been poorly evaluated in assessing real-time intestinal function and novel aspects of structure in patients with disorders of gut-brain interaction. In conclusion, a more complete functional and structural profile that these investigations enable should permit a greater understanding of the effects of dietary manipulation on the gastrointestinal tract and provide clinically relevant information that, amongst other advantages, might permit opportunities for personalized health care delivery.

Development of an Inflamed High Throughput Stem-cell-based Gut Epithelium Model to Assess the Impact of Annexin A1

OBJECTIVE AND DESIGN

Annexin A1 (ANXA1) plays a role in maintaining intestinal hemostasis, especially following mucosal inflammation. The published data about ANXA1 was derived from experimental animal models where there is an overlapping between epithelial and immune cells. There is no in vitro gut epithelial model that can assess the direct effect of ANXA1 on the gut epithelium.

METHODS

We developed high-throughput stem-cell-based murine epithelial cells and bacterial lipopolysaccharides (LPS) were used to induce inflammation. The impact of ANXA1 and its functional part (Ac2-26) was evaluated in the inflamed model. Intestinal integrity was assessed by the transepithelial electrical resistance (TEER), and FITC-Dextran permeability. Epithelial junction proteins were assessed using confocal microscopy and RT-qPCR. Inflammatory cytokines were evaluated by RT-qPCR and ELISA.

RESULTS

LPS challenge mediated a damage in the epithelial cells as shown by a drop in the TEER and an increase in FITC-dextran permeability; reduced the expression of epithelial junctional proteins (Occludin, ZO-1, and Cadherin) and increased the expression of the gut leaky protein, Claudin - 2. ANXA1 and Ac2-26 treatment reduced the previous damaging effects. In addition, ANXA1 and Ac2-26 inhibited the inflammatory responses mediated by the LPS and increased the transcription of the anti-inflammatory cytokine, IL-10.

CONCLUSION

ANXA1 and Ac2-26 directly protect the epithelial integrity by affecting the expression of epithelial junction and inflammatory markers. The inflamed gut model is a reliable tool to study intestinal inflammatory diseases, and to evaluate the efficacy of potential anti-inflammatory drugs and the screening of new drugs that could be candidates for inflammatory bowel disease.

Potential of guar gum as a leaky gut model in broilers: Digestibility, performance, and microbiota responses

Diet is a major modulator of animal resilience and its three pillars: host's immune response, gut microbiota, and intestinal barrier. In the present study, we endeavour to delineate a challenging condition aimed to degrade these pillars and elucidate its impact on broiler performance and nutrient digestibility. To attain this objective, we opted to use guar gum (GG) as a source of galactomannan. A series of three in vivo experiments were conducted employing conventional or semi-purified diets, supplemented with or without GG during the grower phase (14-28 d). Our findings demonstrate a substantial decline in animal performance metrics such as body weight (reduced by 29%, P < 0.001), feed intake (decreased by 12%, P < 0.001), and feed conversion ratio (up to 58% increase, P < 0.001) in the presence of GG at 2%. The supplementation of a semi-purified diet with incremental doses of GG resulted in a linear reduction (P < 0.001) in the apparent total tract digestibility of dry matter and apparent metabolisable energy. Additionally, a marked reduction in ileal endogenous losses, as well as apparent and standardised digestibility of all amino acids with varying proportions (P < 0.05), was observed. These alterations were accompanied by disrupted gut integrity assessed by fluorescein isothiocyanate-dextran (FITC-d) (P < 0.001) as well as an inflammatory status characterised by elevated levels of acute-phase proteins, namely orosomucoid and serum amyloid A in the sera (P = 0.03), and increased mRNA expression levels of IL-1, IL-6, IL-8, Inos, and K203 genes in the ileum, along with a decrease in IgA levels in the gut lumen (P < 0.05). Microbial ecology and activity were characterised by reduced diversity and richness (Shannon index, P = 0.005) in the presence of GG. Consequently, our results revealed diminished levels of short-chain fatty acids (P = 0.01) and their producer genera, such as Clostridium_XIVa and Blautia, in the gut caeca, coupled with excessive accumulation of lactate (17-fold increase, P < 0.01) in the presence of GG at 2%. In addition to providing a more comprehensive characterisation of the GG supplementation as a leaky gut model, our results substantiate a thorough understanding of the intricate adjustments and interplay between the intestinal barrier, immune response, and microbiota. Furthermore, they underscore the significance of feed components in modulating these dynamics.

Western diet components that increase intestinal permeability with implications on health

Intestinal permeability is a physiological property that allows necessary molecules to enter the organism. This property is regulated by tight junction proteins located between intestinal epithelial cells. However, various factors can increase intestinal permeability (IIP), including diet. Specific components in the Western diet (WD), such as monosaccharides, fat, gluten, salt, alcohol, and additives, can affect the tight junctions between enterocytes, leading to increased permeability. This review explains how these components promote IIP and outlines their potential implications for health. In addition, we describe how a reduction in WD consumption may help improve dietary treatment of diseases associated with IIP. Research has shown that some of these components can cause changes in the gut microbiota, leading to dysbiosis, which can promote greater intestinal permeability and displacement of endotoxins into the bloodstream. These endotoxins include lipopolysaccharides derived from gram-negative bacteria, and their presence has been associated with various diseases, such as autoimmune, neurological, and metabolic diseases like diabetes and cardiovascular disease. Therefore, nutrition professionals should promote the reduction of WD consumption and consider the inclusion of healthy diet components as part of the nutritional treatment for diseases associated with increased intestinal permeability.

Dietary nutrition, intestinal microbiota dysbiosis and post-weaning diarrhea in piglets

Weaning is a critical transitional point in the life cycle of piglets. Early weaning can lead to post-weaning syndrome, destroy the intestinal barrier function and microbiota homeostasis, cause diarrhea and threaten the health of piglets. The nutritional components of milk and solid foods consumed by newborn animals can affect the diversity and structure of their intestinal microbiota, and regulate post-weaning diarrhea in piglets. Therefore, this paper reviews the effects and mechanisms of different nutrients, including protein, dietary fiber, dietary fatty acids and dietary electrolyte balance, on diarrhea and health of piglets by regulating intestinal function. Protein is an essential nutrient for the growth of piglets; however, excessive intake will cause many harmful effects, such as allergic reactions, intestinal barrier dysfunction and pathogenic growth, eventually aggravating piglet diarrhea. Dietary fiber is a nutrient that alleviates post-weaning diarrhea in piglets, which is related to its promotion of intestinal epithelial integrity, microbial homeostasis and the production of short-chain fatty acids. In addition, dietary fatty acids and dietary electrolyte balance can also facilitate the growth, function and health of piglets by regulating intestinal epithelial function, immune system and microbiota. Thus, a targeted control of dietary components to promote the establishment of a healthy bacterial community is a significant method for preventing nutritional diarrhea in weaned piglets.

Beneficial effect of heat-killed Lactiplantibacillus plantarum L-137 on intestinal barrier function of rat small intestinal epithelial cells

Heat-killed Lactiplantibacillus plantarum L-137 (HK L-137) has been suggested to enhance the intestinal barrier in obese mice, leading to improvement of metabolic abnormalities and adipose tissue inflammation, and in healthy humans with overweight, leading to improvement of systemic inflammation. However, its detailed mechanism of action has not been clarified. Therefore, this study investigated the effects of HK L-137 on the permeability of rat small intestinal epithelial IEC-6 cells, tight junction-related gene and protein expression and localization, and intracellular signaling pathways involved in barrier function. Treatment of IEC-6 cells with HK L-137 for 26 h significantly reduced the permeability to fluorescein isothiocyanate-dextran (FD-4). HK L-137 also increased gene and protein expression of zonula occludens-1 (ZO-1), an important tight junction protein, without affecting the localization. Furthermore, inhibition of the extracellular signal-regulated kinase (ERK)1/2 pathway in IEC-6 cells canceled the HK L-137-related reduction in permeability to FD-4. Phosphorylation of ERK in IEC-6 cells was induced 15 min after the addition of HK L-137. These results suggest that HK L-137 reduces intestinal permeability partly through activating the ERK pathway and increasing expression of the ZO-1 gene and protein. Enhancement of intestinal barrier function with HK L-137 might be effective in preventing and treating leaky gut, for which no specific therapeutic tool has been established.

Gut Microbiota Mediate the Neuroprotective Effect of Oolong Tea Polyphenols in Cognitive Impairment Induced by Circadian Rhythm Disorder

Oolong tea polyphenols (OTP) have attracted wide attention due to their ability to reduce inflammatory response, regulate gut microbiota, and improve cognitive function. However, exactly how the gut microbiota modulates nervous system activity is still an open question. We previously expounded that supplementing with OTP alleviated neuroinflammation in circadian rhythm disorder (CRD) mice. Here, we showed that OTP can relieve microglia activation by reducing harmful microbial metabolites lipopolysaccharide (LPS) that alleviate CRD-induced cognitive decline. Mechanistically, OTP suppressed the inflammation response by regulating the gut microbiota composition, including upregulating the relative abundance of Muribaculaceae and Clostridia_UCG-014 and downregulating Desulfovibrio, promoting the production of short-chain fatty acids (SCFAs). Moreover, the use of OTP alleviated intestinal barrier damage and decreased the LPS transport to the serum. These results further inhibited the activation of microglia, thus alleviating cognitive impairment by inhibiting neuroinflammation, neuron damage, and neurotoxicity metabolite glutamate elevation. Meanwhile, OTP upregulated the expression of synaptic plasticity-related protein postsynaptic density protein 95 (PSD-95) and synaptophysin (SYN) by elevating the brain-derived neurotrophic factor (BDNF) level. Taken together, our findings suggest that the OTP has the potential to prevent CRD-induced cognition decline by modulating gut microbiota and microbial metabolites.

A Randomized Clinical Trial to Evaluate the Efficacy of an Oral Probiotic in Acne Vulgaris

The relevance of the gut microbiota in some skin inflammatory diseases, including acne vulgaris, has been emphasized. Probiotics could play a role in the modulation of the microbiota, improving the clinical course of this disease. A 12-week randomized, double-blind, placebo-controlled, clinical trial with patients aged 12 to 30 years with acne vulgaris was conducted. The study product was a capsule composed of the probiotic Lacticaseibacillus rhamnosus (CECT 30031) and the cyanobacterium Arthrospira platensis (BEA_IDA_0074B). Patients with improvement in the Acne Global Severity Scale were 10/34 (29.41%) in the placebo group compared with 20/40 (50%) in the probiotic group (p = 0.03). A significant reduction (p = 0.03) in the number of non-inflammatory acne lesions was observed in the probiotic group (-18.60 [-24.38 to -12.82]) vs the placebo group (-10.54 [-17.43 to -3.66]). Regarding the number of total  lesions, a reduction almost reaching statistical significance (p = 0.06) was observed in the probiotic group (-27.94 [-36.35 to -19.53]) compared with the placebo group (-18.31 [-28.21 to -8.41]). In addition, patients with improvement attending the Global Acne Grading System were 7/34 (20.58%) in the placebo group vs 17/40 (42.50%) in the probiotic group (p = 0.02). The number of adverse events was similar in both groups. The probiotic used in this study was effective and well tolerated, and it should be considered for acne vulgaris patients.

Microbiome-based precision nutrition: Prebiotics, probiotics and postbiotics

Microorganisms have been used in nutrition and medicine for thousands of years worldwide, long before humanity knew of their existence. It is now known that the gut microbiota plays a key role in regulating inflammatory, metabolic, immune and neurobiological processes. This text discusses the importance of microbiota-based precision nutrition in gut permeability, as well as the main advances and current limitations of traditional probiotics, new-generation probiotics, psychobiotic probiotics with an effect on emotional health, probiotic foods, prebiotics, and postbiotics such as short-chain fatty acids, neurotransmitters and vitamins. The aim is to provide a theoretical context built on current scientific evidence for the practical application of microbiota-based precision nutrition in specific health fields and in improving health, quality of life and physiological performance.

Gingipain-carrying outer membrane vesicles from Porphyromonas gingivalis cause barrier dysfunction of Caco-2 cells by releasing gingipain into the cytosol

Ingestion of Porphyromonas gingivalis, a periodontal pathogen, disrupts the intestinal barrier in mice. However, the involvement of outer membrane vesicles (OMVs) secreted from P. gingivalis in the destruction of the intestinal barrier remains unclear. In this study, we tested the hypothesis that OMVs carrying gingipains, the major cysteine proteases produced by P. gingivalis, affects the intestinal barrier function. OMVs increased the permeability of the Caco-2 cell monolayer, a human intestinal epithelial cell line, accompanied by degradation of the tight junction protein occludin. In contrast, OMVs prepared from mutant strains devoid of gingipains failed to induce intestinal barrier dysfunction or occludin degradation in Caco-2 cells. A close histological examination revealed the intracellular localization of gingipain-carrying OMVs. Gingipain activity was detected in the cytosolic fraction of Caco-2 cells after incubation with OMVs. These results suggest that gingipains were internalized into intestinal cells through OMVs and transported into the cytosol, where they then directly degraded occludin from the cytosolic side. Thus, P. gingivalis OMVs might destroy the intestinal barrier and induce systemic inflammation via OMV itself or intestinal substances leaked into blood vessels, causing various diseases.

Diet-Induced Gut Dysbiosis and Leaky Gut Syndrome

Chronic gut inflammation promotes the development of metabolic diseases such as obesity. There is growing evidence which suggests that dysbiosis in gut microbiota and metabolites disrupt the integrity of the intestinal barrier and significantly impact the level of inflammation in various tissues, including the liver and adipose tissues. Moreover, dietary sources are connected to the development of leaky gut syndrome through their interaction with the gut microbiota. This review examines the effects of these factors on intestinal microorganisms and the communication pathways between the gut-liver and gut-brain axis. The consumption of diets rich in fats and carbohydrates has been found to weaken the adherence of tight junction proteins in the gastrointestinal tract. Consequently, this allows endotoxins, such as lipopolysaccharides produced by detrimental bacteria, to permeate through portal veins, leading to metabolic endotoxemia and alterations in the gut microbiome composition with reduced production of metabolites, such as short-chain fatty acids. However, the precise correlation between gut microbiota and alternative sweeteners remains uncertain, necessitating further investigation. This study highlights the significance of exploring the impact of diet on gut microbiota and the underlying mechanisms in the gut-liver and gut-brain axis. Nevertheless, limited research on the gut-liver axis poses challenges in comprehending the intricate connections between diet and the gut-brain axis. This underscores the need for comprehensive studies to elucidate the intricate gut-brain mechanisms underlying intestinal health and microbiota.

Nanovesicular Mediation of the Gut-Brain Axis by Probiotics: Insights into Irritable Bowel Syndrome

BACKGROUND

Dysbiosis, influenced by poor diet or stress, is associated with various systemic diseases. Probiotic supplements are recognized for stabilizing gut microbiota and alleviating gastrointestinal issues, like irritable bowel syndrome (IBS). This study focused on the tryptophan pathways, which are important for the regulation of serotonin levels, and on host physiology and behavior regulation.

METHODS

Nanovesicles were isolated from the plasma of subjects with chronic diarrhea, both before and after 60 days of consuming a probiotic mix (Acronelle®, Bromatech S.r.l., Milan, Italy). These nanovesicles were assessed for the presence of Tryptophan 2,3-dioxygenase 2 (TDO 2). Furthermore, the probiotics mix, in combination with H2O2, was used to treat HT29 cells to explore its cytoprotective and anti-stress effect.

RESULTS

In vivo, levels of TDO 2 in nanovesicles were enhanced in the blood after probiotic treatment, suggesting a role in the gut-brain axis. In the in vitro model, a typical H2O2-induced stress effect occurred, which the probiotics mix was able to recover, showing a cytoprotective effect. The probiotics mix treatment significantly reduced the heat shock protein 60 kDa levels and was able to preserve intestinal integrity and barrier function by restoring the expression and redistribution of tight junction proteins. Moreover, the probiotics mix increased the expression of TDO 2 and serotonin receptors.

CONCLUSIONS

This study provides evidence for the gut-brain axis mediation by nanovesicles, influencing central nervous system function.

Theabrownin from Fu Brick tea ameliorates high-fat induced insulin resistance, hepatic steatosis, and inflammation in mice by altering the composition and metabolites of gut microbiota

Fu Brick tea belongs to fermented dark tea, which is one of the six categories of tea. Fu Brick tea has been reported to reduce adiposity and has beneficial effects in the treatment of hypercholesterolemia and cardiovascular disease. Theabrownin (TB) is one of the pigments with the most abundant content in Fu Brick tea. TB has also been reported to have lipid-lowering effects, but its mechanism remains unclear. We found that TB could effectively reduce the insulin resistance and fat deposition induced by a high fat diet (HFD), decrease inflammation in the liver, improve intestinal integrity, and reduce endotoxins in circulation. Further studies showed that TB increased the abundance of Verrucomicrobiota and reduced the abundance of Firmicutes and Desulfobacterota in the intestinal tract of obese mice. The alteration of gut microbiota is closely linked to the metabolic phenotype after TB treatment through correlation analysis. Moreover, TB changed the gut microbial metabolites including L-ornithine, α-ketoglutarate, and glutamine, which have also been found to be upregulated in the liver after TB intervention. In vitro, L-ornithine, α-ketoglutarate, or glutamine significantly reduced lipopolysaccharide (LPS)-induced inflammation in macrophages. Therefore, our results suggest that TB can reduce adiposity, systemic insulin resistance, and liver inflammation induced by a HFD through altering gut microbiota and improving the intestinal tight junction integrity. The metabolites of gut microbiota might also play a role in ameliorating the HFD-induced phenotype by TB.

Gut Microbiome-How Does Two-Month Consumption of Fiber-Enriched Rolls Change Microbiome in Patients Suffering from MASLD?

BACKGROUND

The occurrence of metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing global problem which commonly affects patients with co-existing diseases/conditions, such as type 2 diabetes and dyslipidemia. The effective treatment of MASLD is still limited; however, diet plays a significant role in its management. There are multiple beneficial properties of dietary fiber, including its ability to modify the gut microbiome. Therefore, the aim of this study was to determine the effect of the consumption of fiber-enriched rolls on the gut microbiome and microbial metabolites in patients suffering from MASLD.

METHODS

The participants were recruited according to the inclusion criteria and were required to consume fiber-enriched rolls containing either 6 g or 12 g of fiber. There were three assessment timepoints, when the anthropometric and laboratory parameters were measured, and 16s on nanopore sequencing of the fecal microbiome was conducted.

RESULTS

Firmicutes and Bacteroidetes were the most abundant phyla in the patients living with MASLD. It was demonstrated that the amount of short-chain fatty acids (SCFAs) changed after the consumption of fiber-enriched rolls; however, this was strongly associated with both the timepoint and the type of SCFAs-acetate and butyrate. Additionally, the high-fiber diet was related to the increase in phyla diversity (p = 0.006571).

CONCLUSIONS

Overall, the introduction of an appropriate amount of fiber to the diet seems to be promising for patients suffering from MASLD due to its ability to create an improvement in gut microbiome-related aspects.

Bowel function and inflammation: Is motility the other side of the coin?

Digestion and intestinal absorption allow the body to sustain itself and are the emblematic functions of the bowel. On the flip side, functions also arise from its role as an interface with the environment. Indeed, the gut houses microorganisms, collectively known as the gut microbiota, which interact with the host, and is the site of complex immune activities. Its role in human pathology is complex and scientific evidence is progressively elucidating the functions of the gut, especially regarding the pathogenesis of chronic intestinal diseases and inflammatory conditions affecting various organs and systems. This editorial aims to highlight and relate the factors involved in the pathogenesis of intestinal and systemic inflammation.

Microbial perspective on the skin-gut axis and atopic dermatitis

Atopic dermatitis (AD) is a relapsing inflammatory skin condition that has become a global health issue with complex etiology and mounting prevalence. The association of AD with skin and gut microbiota has been revealed by virtue of the continuous development of sequencing technology and genomics analysis. Also, the gut-brain-skin axis and its mutual crosstalk mechanisms have been gradually verified. Accordingly, the microbiota-skin-gut axis also plays an important role in allergic skin inflammation. Herein, we reviewed the relationship between the microbiota-skin-gut axis and AD, explored the underlying signaling molecules and potential pathways, and focused on the potential mechanisms of probiotics, antimicrobial peptides (AMPs), coagulase-negative staphylococci transplantation, fecal microbiota transplantation, AMPs, and addition of essential fatty acids in alleviating AD, with the aim to provide a new perspective for targeting microbiota in the treatment of allergic skin inflammation.

Intestinal Barrier Dysfunction and Gut Microbiota in Non-Alcoholic Fatty Liver Disease: Assessment, Mechanisms, and Therapeutic Considerations

Non-alcoholic fatty liver disease (NAFLD) is a type of metabolic stress liver injury closely related to insulin resistance (IR) and genetic susceptibility without alcohol consumption, which encompasses a spectrum of liver disorders ranging from simple hepatic lipid accumulation, known as steatosis, to the more severe form of steatohepatitis (NASH). NASH can progress to cirrhosis and hepatocellular carcinoma (HCC), posing significant health risks. As a multisystem disease, NAFLD is closely associated with systemic insulin resistance, central obesity, and metabolic disorders, which contribute to its pathogenesis and the development of extrahepatic complications, such as cardiovascular disease (CVD), type 2 diabetes mellitus, chronic kidney disease, and certain extrahepatic cancers. Recent evidence highlights the indispensable roles of intestinal barrier dysfunction and gut microbiota in the onset and progression of NAFLD/NASH. This review provides a comprehensive insight into the role of intestinal barrier dysfunction and gut microbiota in NAFLD, including intestinal barrier function and assessment, inflammatory factors, TLR4 signaling, and the gut-liver axis. Finally, we conclude with a discussion on the potential therapeutic strategies targeting gut permeability and gut microbiota in individuals with NAFLD/NASH, such as interventions with medications/probiotics, fecal transplantation (FMT), and modifications in lifestyle, including exercise and diet.

Correlation between the gut microbiome and neurodegenerative diseases: a review of metagenomics evidence

A growing body of evidence suggests that the gut microbiota contributes to the development of neurodegenerative diseases via the microbiota-gut-brain axis. As a contributing factor, microbiota dysbiosis always occurs in pathological changes of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. High-throughput sequencing technology has helped to reveal that the bidirectional communication between the central nervous system and the enteric nervous system is facilitated by the microbiota's diverse microorganisms, and for both neuroimmune and neuroendocrine systems. Here, we summarize the bioinformatics analysis and wet-biology validation for the gut metagenomics in neurodegenerative diseases, with an emphasis on multi-omics studies and the gut virome. The pathogen-associated signaling biomarkers for identifying brain disorders and potential therapeutic targets are also elucidated. Finally, we discuss the role of diet, prebiotics, probiotics, postbiotics and exercise interventions in remodeling the microbiome and reducing the symptoms of neurodegenerative diseases.

The inhibitory effects of live and UV-killed Akkermansia muciniphila and its derivatives on cytotoxicity and inflammatory response induced by Clostridioides difficile RT001 in vitro

Clostridioides difficile infection (CDI) is the leading cause of healthcare-acquired infections worldwide. Probiotics are widely recommended to prevent CDI and its recurrences. Akkermansia muciniphila, as a therapeutic symbiont colonizing the intestinal mucosal layer, is considered to be a promising next-generation probiotic. In this work, we assessed the inhibitory effects of A. muciniphila MucT and its derivatives on cytotoxicity and inflammatory response induced by C. difficile RT001 in Caco-2 cells. The results obtained from SEM revealed that the morphology of UV-killed A. muciniphila remained unchanged after UV inactivation. TEM analysis showed that A. muciniphila-isolated extracellular vesicles (EVs) were spherical and ranged from 50 to 200 nm in size. Toxigenic supernatant (Tox-S) of C. difficile RT001 (500 μg/ml) significantly (P <0.01) reduced the cell viability of Caco-2 cells. Caco-2 cells treated with live (MOI 10), UV-killed (MOI 10), cell-free supernatant (CFS, 106 cfu/ml), and EVs (20 μg/ml) of A. muciniphila exhibited over 90% viability in comparison to untreated control. The neutralized CFS preparation using A. muciniphila and its derivatives could notably reduce the expression level of inflammatory markers. Additionally, A. muciniphila and its derivatives modulated the production of IL-1β, TNF-α, and IL-10 in Tox-S stimulated Caco-2 cells. We demonstrated that A. muciniphila and its derivatives can modulate changes in the gut barrier-related genes and inflammatory response caused by C. difficile Tox-S in Caco-2 cells.