Intestinal Barrier Dysfunction Research Articles

Rol de la alteración del eje microbiota-intestino-hígado en la enfermedad hepática esteatósica asociada a disfunción metabólica

Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the leading causes of liver morbidity worldwide, including conditions such as hepatocellular carcinoma and the need for liver transplantation, with a particularly high prevalence in Latin America. The pathogenesis of MASLD is multifactorial, involving both genetic and environmental factors, including dysfunction of the gut-liver axis. The mechanisms involved in the progression of liver disease to cirrhosis are not yet fully understood. Recently, the intestinal microbiota has been recognized as playing a crucial role in disease progression by modulating systemic and hepatic inflammatory responses. In MASLD patients, microbial dysbiosis contributes to intestinal barrier dysfunction, increasing intestinal permeability and facilitating the translocation of microbial products to the liver, thereby exacerbating inflammation and hepatic damage. Additionally, alterations in bile acid levels and microbial metabolites further reinforce this pathological cycle. Therapeutic strategies aimed at restoring microbial balance—such as fecal microbiota transplantation, probiotics, prebiotics, and synbiotics—have shown promising results in modulating the microbiota-gut-liver axis and slowing MASLD progression. Further studies are needed to fully understand their impact on the pathophysiology of MASLD and to strengthen their integration into current therapeutic protocols for this disease.

Lipocalin-2 and intestinal diseases.

Dysfunction of the intestinal barrier is a prevalent phenomenon observed across a spectrum of diseases, encompassing conditions such as mesenteric artery dissection, inflammatory bowel disease, cirrhosis, and sepsis. In these pathological states, the integrity of the intestinal barrier, which normally serves to regulate the selective passage of substances between the gut lumen and the bloodstream, becomes compromised. This compromised barrier function can lead to a range of adverse consequences, including increased permeability to harmful substances, the translocation of bacteria and their products into systemic circulation, and heightened inflammatory responses within the gut and beyond. Understanding the mechanisms underlying intestinal barrier dysfunction in these diverse disease contexts is crucial for the development of targeted therapeutic interventions aimed at restoring barrier integrity and ameliorating disease progression. Lipocalin-2 (LCN2) expression is significantly upregulated during episodes of intestinal inflammation, making it a pivotal indicator for gauging the extent of such inflammatory processes. Notably, however, LCN2 derived from distinct cellular sources, whether intestinal epithelial cells or immune cells, exhibits notably divergent functional characteristics. Furthermore, the multifaceted nature of LCN2 is underscored by its varying roles across different diseases, sometimes even demonstrating contradictory effects.

REGγ-mediated Barrier Disruption and NF-κB Activation Aggravates Intestinal Inflammation in Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) stands as the most prevalent and severe gastrointestinal ailment affecting premature newborns, particularly those with extremely low birth weights. Intestinal barrier dysfunction emerges as a crucial factor in NEC's pathogenesis. REGγ predominantly manifests in the intestinal epithelium and has shown to regulate experimental colitis. However, the potential correlation between REGγ and NEC remains ambiguous. This study reveals that REGγ is notably overexpressed in both human and murine NEC samples. REGγ-deficient mice displayed improvements in intestinal mucosal inflammation and reduced NEC severity. Additionally, REGγ deficiency notably lowered the expression of phosphorylated transcription factor p65 and inflammatory factors in intestinal epithelial cells of NEC-afflicted mice. REGγ exacerbates the local inflammation by triggering the degradation of IκBɛ, a negative regulator of NFκB. Clinically, REGγ and p65 expression levels exhibit a positive correlation in NEC specimens. Moreover, pre-treatment of mice with a p65 inhibitor effectively suppressed the expression of inflammatory mediators and alleviated REGγ-mediated NEC development. These findings underscore that abnormal upregulation of REGγ triggers NEC development by enhancing NF-κB activity and exacerbating epithelial barrier dysfunction. Thus, novel therapeutic approaches targeting REGγ inhibition may offer enhanced treatment for NEC.

Retraction Note: Embelin alleviates weaned piglets intestinal inflammation and barrier dysfunction via PCAF/NF-κB signaling pathway in intestinal epithelial cells

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1186/s40104-022-00787-z.

Sodium Butyrate-Loaded Microspheres With Enhanced Bioavailability for Targeted Treatment of Intestinal Barrier Injury.

Intestinal barrier dysfunction is related to diseases such as inflammatory bowel disease (IBD) and severe acute pancreatitis (SAP). Butyrate and its derivatives (e.g., sodium butyrate (SB)) can alleviate gut inflammatory responses. Nevertheless, these substances usually cannot fully exert protective effects due to low bioavailability. This research aimed to offer microspheres for treating intestinal barrier injury. Sodium alginate solution is prepared to dissolve SB, followed by mixingwith chitosan (CS)-protocatechuic aldehyde (PA)/calcium chloride solution. The required CS-PA/calcium alginate/SB (CPC/SB) microspheres are formed in this manner. Subsequently, the therapeutic effects of CPC/SB microspheres on intestinal barrier injury through in vivo dextran sulfate sodium salt (DSS)-induced IBD and sodium taurocholate (STC)-induced SAP models is explored. Results: The CPC/SB microspheres exhibited excellent antioxidant properties. In vivo bioluminescence imaging experiment confirmed the microspheres effectively targeted the inflammatory gut in IBD. Further in vivo experimental results indicated the microspheres significantly repaired intestinal barrier damage, exerting protective effects in IBD and SAP. Additionally, 16S rDNA sequencing explained the microspheres can regulate the balance between harmful and beneficial bacteria (such as Alistipes, Odoribacter, and Rikenellaceae RC9). This study provides a possible synthetic strategy of microsphere carriers to serve as a potential therapeutic tool for intestinal barrier injury.

The gut microbial metabolite phenylacetylglutamine increases susceptibility to atrial fibrillation after myocardial infarction through ferroptosis and NLRP3 inflammasome.

Myocardial infarction (MI) is an important risk factor for the development of atrial fibrillation (AF), and the gut microbial metabolite phenylacetylglutamine (PAGln) is strongly associated with the prognosis of MI patients. However, whether PAGln is involved in the regulation of AF after MI is currently unknown. Therefore, the present study aimed to explore the effect of PAGln on the susceptibility to AF after MI.MI model was constructed by surgically ligating the left anterior descending branch of the coronary artery. PAGln was administered by intraperitoneal injection for 7 consecutive days starting after surgery and then investigated by histopathologic, molecular biological, and electrophysiologic studies.Myocardial ischemia resulted in intestinal barrier dysfunction and significantly increased circulating levels of PAGln. Compared with the myocardial ischemia group, administration of PAGln significantly exacerbated atrial fibrosis and atrial electrical remodeling in mice after myocardial ischemia, as evidenced by shortening of the ERP (at varying pacing cycle lengths of 40, 60, 80, and 100), ion channel remodeling (Nav1.5, Cav1.2, and Kv1.5), and decreased expression of CX40, which led to an increase in the susceptibility to AF (54.5% vs. 90.9%, P < 0.05). In addition, administration of PAGln further exacerbated MI-induced intestinal barrier dysfunction compared with the MI group. Mechanistically, PAGln may affect atrial remodeling and AF susceptibility after MI by modulating ferroptosis and NLRP3 inflammasome.The present study preliminarily reveals that the gut microbial metabolite PAGln exacerbates post-MI AF remodeling and AF susceptibility, possibly through ferroptosis and activation of NLRP3 inflammasome.

Dihydromyricetin Suppresses Lipopolysaccharide-Induced Intestinal Injury Through Reducing Reactive Oxygen Species Generation and NOD-Like Receptor Pyrin Domain Containing 3 Inflammasome Activation.

As an integral component of the gram-negative bacterial cellular envelope, excess production of lipopolysaccharide (LPS) regularly precipitates causing intestinal damage and barrier dysfunction in avian species. Dihydromyricetin (DHM), a naturally occurring constituent in rattan tea, exhibits protective characteristics against various tissue injuries. However, the intervention mechanism of DHM on intestinal injury induced by LPS in chickens has not been determined. Consequently, this study aimed to elucidate the mechanisms through which DHM mitigates LPS-induced intestinal damage in chickens through the reactive oxygen species (ROS)-NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome. Primary intestinal epithelial cells (IECs) were isolated and cultured from 14-day-old specific pathogen free (SPF) chicken embryos, and DHM ranging from 20 to 320 μmol/L increased cell survival rates. Additionally, DHM at 20 and 40 μmol/L demonstrated reduction in oxidative stress and ROS accumulation, mirroring the impact of ROS inhibitor (2.5 mmol/L NAC). DHM efficiently regulated ROS production, thereby augmenting ZO-1, occludin and claudin-1 expression to enhance barrier function; upregulating bcl-2 expression and downregulating bax and caspase-3 expression to regulate apoptosis and suppressing inflammation in IECs. Suppression of ROS subsequently attenuates NLRP3 inflammasome activation, leading to a remarkable downregulation of IL-1β, IL-18 and lactate dehydrogenase (LDH) secretion, consistent with direct inactivation of NLRP3 inflammasome (10 μmol/L MCC950). Notably, DHM diminished IL-1β and IL-18 levels and LDH activity via suppression of ROS-regulated NLRP3 and caspase-1 expression and activation. In summary, DHM prevents LPS-induced intestinal impairment by modulating ROS generation and NLRP3 inflammasome activation.

Myosin light chain kinase-mediated epithelial barrier dysfunction as a potential pathogenic mechanism of afatinib-induced diarrheas: A study in human colonoid model

Diarrheas are an important adverse effect of afatinib, a tyrosine kinase inhibitor (TKI) anti-cancer drug, leading to mortality and morbidity in cancer patients with their pathophysiological mechanisms related to intestinal barrier dysfunctions being poorly understood. This study aimed to investigate the effect of afatinib on intestinal epithelial barrier integrity using a human colon-derived organoid model (colonoids). Afatinib (0.5 μM) significantly decreased the transepithelial electrical resistance (TEER) by ∼60% and increased apical-to-basolateral dextran flux by >20 folds without causing apparent cytotoxicity in human colonoids. The delocalization of zonular occluding-1 (ZO-1) and a decrease in mRNA and protein expression of claudin-4 and ZO-1 were also observed in the afatinib-treated human colonoids. Afatinib induced nuclear translocation of nuclear factor kappa B (NF-κB) as well as mRNA and protein expression of NF-κB target including tumor necrosis factor (TNF)-alpha, interleukin-8 (IL-8), and inducible nitric oxide synthase (iNOS) indicating the initiation of the NF-κB-mediated epithelial inflammatory responses. Interestingly, afatinib induced mRNA and protein expression of myosin light chain (MLC) kinase (MLCK) and MLC phosphorylation, a known inducer of intestinal epithelial barrier disruption. Treatment with iNOS inhibitor (1400W) or MLCK inhibitor (ML-7) reversed the effect of afatinib on mRNA expressions of ZO-1 and claudin-4, and TEER. Collectively, our results indicate that afatinib induces intestinal epithelial barrier dysfunction via mechanisms involving NF-κB-iNOS-MLCK pathways. This finding may pave the way for developing therapeutic strategies to reduce adverse effects and enhance efficacy of TKI in cancer patients.

Targeting gut microbiota and metabolism profiles with coated sodium butyrate to ameliorate high-energy and low-protein diet-induced intestinal barrier dysfunction in laying hens

High energy diet are a risk factor for intestinal barrier damage. Butyrate, a major energy source for intestinal epithelial cells, has been shown to improve barrier dysfunction and modulate the gut microbiota. In this trial, we examined the preventative effect of coated sodium butyrate (CSB) on high-energy low-protein (HELP)-induced intestinal barrier injury in laying hens, and also worked to determine the underlying mechanisms by an integrative analysis of gut microbiota and the metabolome. A total of 216 healthy 28-weeks-old Huafeng laying hens were randomly assigned to 3 groups with 6 replicates each: the CON group (normal diet), HELP group (high-energy and low-protein diet) and CH500 group (500 mg/kg CSB added to HELP diet). The duration of the trial encompassed a period of 10 weeks. The results revealed that CSB treatment improved the laying rate (P<0.05) and mitigated the detrimental effects on intestinal barrier function and the inflammatory response induced by the HELP diet in laying hens (P<0.05). Microbial profiling analysis revealed that the CSB treatment reshaped the HELP-perturbed gut microbiota, and promoted the growth of beneficial bacteria (P<0.05). Untargeted metabolomics analysis revealed that CSB reduced the metabolites associated with intestinal inflammation (P<0.05). In conclusion, CSB did not merely modulate alterations in the gut microbiota composition and microbial metabolites but also yielded increased egg production, while mitigating intestinal barrier dysfunction and inflammatory responses induced by HELP in laying hens.

Downregulated KLF4, induced by m6A modification, aggravates intestinal barrier dysfunction in inflammatory bowel disease

BackgroundKrüppel-like factor 4 (KLF4), a transcription factor, is involved in various biological processes. However, the role of KLF4 in regulating the intestinal epithelial barrier (IEB) in inflammatory bowel disease (IBD) and its mechanism have not been extensively studied.MethodsKLF4 expression in IBD patients and colitis mice was analyzed using Gene Expression Omnibus(GEO) database, immunohistochemistry (IHC) and Western blot. The roles of KLF4 in IEB and colitis symptoms were verified in dextran sulfate sodium (DSS)-induced and 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis model mice using an adenovirus carrying KLF4 shRNA (shKLF4-Adv). Furthermore, the influence of KLF4 on trans-epithelium electrical resistance (TEER), paracellular permeability, apical junction complex (AJC) protein expression and apoptosis was assessed in vitro and in vivo. MeRIP and RIP assays were used to verify the effects of m6A modification on KLF4 expression.ResultsKLF4 expression was significantly decreased in IBD patients and was negatively associated with inflammatory features. KLF4 deletion aggravated colitis symptoms and IEB injuries by reducing AJC protein expression and increasing apoptosis in mice with colitis. Furthermore, KLF4 transcriptionally regulated the expression of AJC proteins and inhibited apoptosis by reducing cellular ROS levels and proinflammatory cytokine expression. Moreover, we observed that METTL3/ALKBH5/YTHDF2-mediated m6A modification led to a decrease in KLF4 expression in Caco-2 cells. In addition, APTO-253, an inducer of KLF4, exhibited a synergistic effect with mesalazine on IEB function.ConclusionsOur study demonstrated that KLF4 is a crucial regulator of IEB, suggesting that targeting KLF4 may be a promising therapeutic alternative for IBD.

Atractylenolide III ameliorates DSS-induced colitis by improving intestinal epithelial barrier via suppressing the NF-κB-Mediated MLCK-pMLC signaling pathway

This study is to demonstrate the protection of atractylenolide III (AT III) on intestinal barrier dysfunction in ulcerative colitis (UC). UC model was established by 3% dextran sulfate sodium (DSS), and TNF-α was used to induce dysfunction in the intestinal epithelial barrier. TEER, FD-4 transmembrane flux and DAI were measured. Histopathological changes was identified by H&E staining, TJ structure changes were observed by TEM, IL-1β and TNF-α contents were measured by ELISA, bacterial translocation was investigated by FISH. The expressions of ZO-1, occludin, and the proterins in the MLCK/p-MLC and NF-κB pathways were analyzed by Western blotting or immunofluorescence. The results indicated that AT III alleviate the symptoms of DSS-induced colitis, reduce the disruption of intestinal epithelial barrier, and decrease FD4. Moreover, AT III inhibited the destruction of intestinal epithelial TJ structure and bacterial translocation in UC mice. AT III reversed the high levels of IL-1β and TNF-α, the decrease of occludin, ZO-1 expressions. Furthermore, AT III showed similar effects to PDTC (pyrrolidinedithiocarbamate) in ameliorating the disruption of the TNF-α-induced TEER and FD-4 disruption, MLCK protein expression, and MLC2 phosphorylation. In conclusion, AT III mitigates the dysfunction of intestinal epithelial barrier in UC through the NF-κB-mediated MLCK/p-MLC signaling pathway.

Therapeutic potential of Lacticaseibacillus rhamnosus grx10 and its derived postbiotic through gut microbiota and MAPK/MLCK/MLC pathway-mediated intestinal barrier repairment in ulcerative colitis.

Lacticaseibacillus rhamnosus grx10 (grx10) has shown promising potential in promoting intestinal health as predicted by genomic and metabolomic analyses. Given the increasing prevalence of ulcerative colitis (UC) and the limitations of existing treatments, exploring alternative therapeutic strategies is essential. This study explored the therapeutic effects and underlying mechanisms of grx10 and its derived postbiotic (P-grx10) in a mouse model of dextran sulfate sodium (DSS)-induced chronic UC. The intervention with grx10 and P-grx10 significantly alleviated clinical symptoms and improved biochemical markers in UC mice. These effects included reducing the disease activity index (DAI), improving colon length and histopathological damage, decreasing the secretion of inflammatory cytokines, and preventing the reduction of antioxidant enzymes. Additionally, grx10 and P-grx10 downregulated key proteins in the Mitogen-Activated Protein Kinase (MAPK)/myosin light chain kinase (MLCK)/myosin light chain (MLC) pathway, prevented the dissociation of tight junction (TJ) proteins and E-cadherin, reduced intestinal permeability, and restored the integrity of the intestinal barrier. Furthermore, both grx10 and P-grx10 modulated the composition and abundance of gut microbiota, helping to maintain intestinal microbiome homeostasis. In conclusion, this study provided evidence regarding the role of grx10 and P-grx10 in alleviating intestinal barrier dysfunction associated with UC and restoring gut microbiota balance. Notably, P-grx10 exhibited higher anti-inflammatory activity and better restoration of intestinal barrier function, whereas the live probiotic grx10 showed a stronger regulatory effect on the gut microbiota. These findings suggest that grx10 and P-grx10 could serve as promising nutritional adjunct therapies for UC, providing novel insights into the distinct roles of probiotic and its derived postbiotic in UC treatment.

Lactiplantibacillus plantarum Y44 Complex Fermented Milk Regulates Lipid Metabolism in Mice Fed with High-Fat Diet by Modulating Gut Microbiota.

The benefits of fermented milk containing Lactiplantibacillus plantarum (L. plantarum) Y44, known for its weight loss properties, remain unclear. For this, we evaluated the effects of the complex fermented milk (Y44-CFM), obtained through the cofermentation of cow's milk and soybean milk with L. plantarum Y44 and traditional starters, on high-fat diet (HFD)-fed C57BL/6 mice. Our study found that the oral administration of Y44-CFM significantly reduced body weight gain and hepatic lipid accumulation in HFD-fed mice while also mitigating liver injury. Additionally, Y44-CFM regulated the expression of enzymes associated with lipid metabolism in the serum, as well as the corresponding or related genes in the liver, such as fatty acid synthase. Furthermore, HFD-induced systemic inflammation, oxidative stress, and intestinal barrier dysfunction were improved. The primary alterations in hepatic metabolism involved glycerophospholipids and amino acids, including the biosynthesis of valine, leucine, and isoleucine. The diversity and overall structure of the gut microbiota were also regulated, resulting in a significant decrease in the ratio of Firmicutes to Bacteroidetes (F/B) and unclassified_f_Lachnospiraceae, along with a notable increase in Oscillospiraceae. The correlation analysis indicated that Y44-CFM influenced hepatic lipid metabolism by mediating intestinal flora and its production of short-chain fatty acids, ultimately leading to weight reduction.

Regulatory Effect of Fucoidan Hydrolysates on Lipopolysaccharide-Induced Inflammation and Intestinal Barrier Dysfunction in Caco-2 and RAW264.7 Cells Co-Cultures.

Fucoidan, a sulfated polysaccharide rich in fucose, is derived from brown algae and marine invertebrates. Multiple bioactivities have been shown with fucoidan, while growing attraction has emerged in its low-molecular-weight (Mw) hydrolysates. Here, the anti-inflammatory effect of fucoidan, low-Mw acidolyzed fucoidan (LMAF, <1.5 kDa), and high-Mw acidolyzed fucoidan (HMAF, 1.5-20 kDa) were investigated in vitro using lipopolysaccharide (LPS)-stimulated Caco-2 and RAW264.7 co-cultures. Fucoidan, LMAF, and HMAF with different structures exhibited varied anti-inflammatory effects. LMAF and HMAF effectively decreased the nitric oxide release of RAW264.7 cells. LMAF exhibited a competitive effect in reducing tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 levels compared to HMAF and fucoidan. Transcriptome of RAW264.7 revealed that LPS and LMAF mainly regulated the transcriptional expression of genes, including Tnf, Il6, Il1b, Junb, and Nfkb1 in the TNF signaling pathway, NF-kappa B signaling pathway, and cytokine-cytokine receptor interaction. RT-PCR results indicated that LMAF markedly reduced the LPS-elevated expression of Cxcl2, Tnf, Ccl2, Il1b, and Csf2. Moreover, LMAF effectively increased the proteins expression of Claudin-1, Occludin, and Zonula occluden-1 in Caco-2 cells. This study highlights the potential of LMAF to improve inflammation and intestinal barrier integrity, offering a foundation for further application of low-Mw fucoidan hydrolysates.

Inulin alleviates inflammatory response and gut barrier dysfunction via modulating microbiota in lipopolysaccharide-challenged broilers

This study was conducted to explore the protective effects of inulin against lipopolysaccharide (LPS)-induced inflammatory response and intestinal barrier dysfunction in broilers. 108 broilers were allocated to 3 treatments: 1) non-challenged broilers (Control, CON); 2) LPS-challenged broilers (LPS); 3) LPS-challenged broilers fed the basal diet supplemented with 15 g/kg of inulin (Inulin + LPS). At 21 d of age, the LPS-challenged groups received an intraperitoneal injection of LPS, and the CON group received an equal volume of saline. After 4 h of LPS exposure, samples of blood, intestinal mucosa and cecal digesta were collected. The results showed that LPS challenge induced systemic inflammation and damaged intestinal barrier function, whereas inulin attenuated LPS-induced production of pro-inflammatory cytokines by inhibiting the activation of TLR4 and NF-κB p65, and enhanced intestinal barrier function. In addition, LPS stimulation caused cecal microbial dysbiosis as shown by increased abundance of pathogenic bacteria including Ruminococcus_torques_group, Escherichia-Shigella and Subdoligranulum, while supplementation of inulin increased abundance of beneficial bacteria Faecalibacterium and Anaeroplasma, and metabolite production including propionate and butyrate concentrations. In conclusion, dietary supplementation of inulin could partially alleviate LPS-induced inflammation and intestinal barrier injury by modulating intestinal microbiota, thereby minimizing growth retardation of broilers. Our results provide a basis for the rational utilization of inulin in alleviating immune stress in broiler production.

The phenotype of necrotizing enterocolitis correlates with distinct changes of intestinal junctional proteins

Necrotizing enterocolitis (NEC) is a major cause of mortality in preterm infants. Its pathophysiology remains poorly understood but intestinal epithelial barrier dysfunction contributes to the disease. We characterized junctional proteins in intestinal specimens from preterm infants. Samples from 27 patients with NEC and 20 patients with focal intestinal perforation (FIP) from the center of the specimens (affected) or the macroscopically healthy resection margins whenever available (non-affected) were collected. NEC patients displayed higher mortality and more commonly occurrence of impaired glucose homeostasis, patent ductus arteriosus, anemia and antibiotic treatment compared to FIP patients. Discrimination between NEC and FIP was not possible in affected areas based on H.E. staining using a newly developed scoring system. Immunofluorescence revealed reduced Claudin-3 in affected NEC samples and decreased Claudin-4 in affected FIP and all NEC samples. E-cadherin and Desmoglein-2 were reduced in a subgroup of the affected NEC samples. Plakophilin-2 was decreased in intestine affected by FIP and unaffected intestine in patients with NEC. In affected areas of NEC, Plakophilin-2 was completely lost. Plakoglobin reduction in affected NEC samples correlated with poor survival. This study provides novel insights into changes of junctional proteins in NEC, suggesting Claudin-3 and Plakophilin-2 as diagnostic markers to differentiate FIP from NEC and reduced Plakoglobin as a prognostic marker.

Metasilicate-based alkaline mineral water improves the growth performance of weaned piglets by maintaining gut-liver axis homeostasis through microbiota-mediated secondary bile acid pathway

Weaning stress causes substantial economic loss in the swine industry. Moreover, weaning-induced intestinal barrier damage and dysfunction of the gut-liver axis are associated with reduced growth performance in piglets. Metasilicate-based alkaline mineral water (AMW) has shown potential therapeutic effects on gastrointestinal disorders; however, the mechanisms involved and their overall effects on the gut-liver axis have not been explored. Here, sodium metasilicate (SMS) was used to prepare metasilicate-based AMW (basal water + 500 mg/L SMS). A total of 240 newly weaned piglets were allocated to the Control and SMS groups (6 replicate pens per group and 20 piglets per pen) for a 15-day trial period. Histopathological evaluations were conducted using hematoxylin and eosin staining. To analyze the composition of the gut microbiota, 16S rRNA PacBio SMRT Gene Full-Length Sequencing was performed. Western blotting and immunofluorescence were employed to assess protein expression levels. Our results indicated that metasilicate-based AMW effectively alleviated weaning-induced colonic or liver morphological injury and inflammatory response, as well as liver cholesterol metabolism disorders. Further analysis showed that metasilicate-based AMW promoted deoxycholic acid (DCA) biosynthesis by increasing the abundance of Lactobacillus_delbrueckii in the colon (P < 0.001). This consequently improved weaning-induced colon and liver injury and dysfunction through the DCA-secondary bile acid (SBA) receptors (SBAR)-nuclear factor-kappaB (NF-κB)/NOD-like receptor family pyrin domain-containing 3 (NLRP3) pathways. Growth performance parameters, including final body weight (P = 0.034) and average daily gain (P < 0.001), in the SMS group were significantly higher than those in the Control group. Therefore, metasilicate-based AMW maintains gut-liver axis homeostasis by regulating the microbiota-mediated SBA-SBAR pathway in piglets under weaning stress. Our research provides a new strategy for mitigating stress-induced gut-liver axis dysfunction in weaned piglets.

Rifaximin alleviates intestinal barrier disruption and systemic inflammation via the PXR/NFκB/MLCK pathway and modulates intestinal Lachnospiraceae abundance in heat-stroke mice

Heatstroke is a critical condition with a high mortality rate and intestinal barrier dysfunction is a key factor in its progression to sepsis in some patients. This study aimed to explore the protective effects of rifaximin on the intestinal barrier in heat-stroke mice and the underlying mechanisms. A mouse model of heat stroke was established, followed by rifaximin intervention. Rifaximin significantly improved survival rates, reduced core body temperature, and alleviated intestinal tissue damage. Further mechanistic studies revealed that rifaximin restored heat stroke-induced damage to intestinal barrier function by upregulating the expression of the tight junction proteins, ZO-1 and occludin. Additionally, 16S rRNA sequencing showed that rifaximin significantly increased the abundance of Lachnospiraceae in the gut and enhanced short-chain fatty acid butyrate levels. In vitro experiment results revealed that butyrate promotes the expression of the intestinal epithelial cell protein MUC2, thereby strengthening the intestinal barrier. Rifaximin also activated the pregnane X receptor (PXR) signaling pathway and inhibited the NF-κB/MLCK signaling pathway, reducing the permeability of intestinal epithelial cells. This study demonstrated that rifaximin protects the intestinal barrier in mice with heat stroke through multiple pathways by modulating the gut microbiota, increasing butyrate production, and activating the PXR signaling pathway. These findings provide a new theoretical basis for the clinical application of rifaximin in heat stroke treatment.

Galactooligosaccharides and Limosilactobacillus reuteri synergistically alleviate gut inflammation and barrier dysfunction by enriching Bacteroides acidifaciens for pentadecanoic acid biosynthesis

Ulcerative colitis (UC) is a debilitating inflammatory bowel disease characterized by intestinal inflammation, barrier dysfunction, and dysbiosis, with limited treatment options available. This study systematically investigates the therapeutic potential of a synbiotic composed of galactooligosaccharides (GOS) and Limosilactobacillus reuteri in a murine model of colitis, revealing that GOS and L. reuteri synergistically protect against intestinal inflammation and barrier dysfunction by promoting the synthesis of pentadecanoic acid, an odd-chain fatty acid, from Bacteroides acidifaciens. Notably, the synbiotic, B. acidifaciens, and pentadecanoic acid are each capable of suppressing intestinal inflammation and enhancing tight junction by inhibiting NF-κB activation. Furthermore, similar reduction in B. acidifaciens and pentadecanoic acid levels are also observed in the feces from both human UC patients and lipopolysaccharide-induced intestinal inflammation in pigs. Our findings elucidate the protective mechanism of the synbiotic and highlight its therapeutic potential, along with B. acidifaciens and pentadecanoic acid, for UC and other intestinal inflammatory disorders.

Black Rice Extract Reduces Body Weight, Waist Circumference, Body Mass Index and Lipopolysaccharide in Obese Subjects: A Preliminary Study

BACKGROUND: The prevalence of obesity, or an excessive fat accumulation, is keep increasing. In obesity, inflammation can be induced by leaky gut due to the intestinal tight junction barrier dysfunction. Zonula occludens-1 (ZO-1) plays a role in developing intestinal tight junction barrier dysfunction and gut microbiota imbalance, thus promote the translocation of bacterial endotoxin characterized by lipopolysaccharide (LPS) into circulation. Black rice extract (BRE) has been known to have anti-inflammatory property. This study was conducted to investigate the effect of BRE on body weight (BW), waist circumference (WC), body mass index (BMI), ZO-1 and LPS of obese patients.METHODS: Twenty-three male subjects were divided into non-obese group (NOG), obese group (COG) and BRE-obese group (BOG). Subjects in BOG received a daily dose of 5.6 g/day BRE for 4 weeks. BW, WC and BMI, serum ZO-1 and LPS were measured before and after treatment.RESULTS: BRE was prepared successfully and free from microbial contamination. Treatment of BRE for 4 weeks reduce BW (95.40±5.78 vs. 94.59±6.00 kg, p=0.043), WC (109.25±3.55 vs. 107.50±3.46 cm, p=0.000) BMI (32.65±1.86 vs. 32.18±1.80, p=0.000) and LPS (222.27±38.63 vs. 131.63±9.70 ng/mL, p=0.020) of obese subjects. The pre-post ZO-1 levels in all groups were not significantly different (p&gt;0.05).CONCLUSION: Treatment of 5.6 gr BRE daily for four weeks can reduce BW, WC, BMI and serum LPS, but not serum ZO-1 in obese patients. Therefore, BRE may reduce inflammation in obesity.KEYWORDS: black rice, obesity, BW, WC, BMI, LPS, ZO-1