Effects of elafibranor on liver fibrosis and gut barrier function in a mouse model of alcohol-associated liver disease

BACKGROUND Alcohol-associated liver disease(ALD)is a leading cause of liver-related morbidity and mortality,but there are no therapeutic targets and modalities to prevent ALD-related liver fibrosis.Peroxisome proliferator activated receptor(PPAR)α and δ play a key role in lipid metabolism and intestinal barrier homeostasis,which are major contributors to the pathological progression of ALD.Meanwhile,elafibranor(EFN),which is a dual PPARαand PPARδagonist,has reached a phase III clinical trial for the treatment of metabolic dysfunctionassociated steatotic liver disease and primary biliary cholangitis.However,the benefits of EFN for ALD treatment is unknown.AIM To evaluate the inhibitory effects of EFN on liver fibrosis and gut-intestinal barrier dysfunction in an ALD mouse model.METHODS ALD-related liver fibrosis was induced in female C57BL/6J mice by feeding a 2.5% ethanol(EtOH)-containing Lieber-DeCarli liquid diet and intraperitoneally injecting carbon tetrachloride thrice weekly(1 mL/kg)for 8 weeks.EFN(3 and 10 mg/kg/day)was orally administered during the experimental period.Histological and molecular analyses were performed to assess the effect of EFN on steatohepatitis,fibrosis,and intestinal barrier integrity.The EFN effects on HepG2 lipotoxicity and Caco-2 barrier function were evaluated by cell-based assays.RESULTS The hepatic steatosis,apoptosis,and fibrosis in the ALD mice model were significantly attenuated by EFN treatment.EFN promoted lipolysis and β-oxidation and enhanced autophagic and antioxidant capacities in EtOH-stimulated HepG2 cells,primarily through PPARαactivation.Moreover,EFN inhibited the Kupffer cell-mediated inflammatory response,with blunted hepatic exposure to lipopolysaccharide(LPS)and toll like receptor 4(TLR4)/nuclear factor kappa B(NF-κB)signaling.EFN improved intestinal hyperpermeability by restoring tight junction proteins and autophagy and by inhibiting apoptosis and proinflammatory responses.The protective effect on intestinal barrier function in the EtOH-stimulated Caco-2 cells was predominantly mediated by PPARδ activation.CONCLUSION EFN reduced ALD-related fibrosis by inhibiting lipid accumulation and apoptosis,enhancing hepatocyte autophagic and antioxidant capacities,and suppressing LPS/TLR4/NF-κB-mediated inflammatory responses by restoring intestinal barrier function.

Functional and morphological changes of the gut barrier during the restitution process after hemorrhagic shock

AIM： To investigate the functional, morphological changes of the gut barrier during the restitution process after hemorrhagic shock, and the regional differences of the large intestine and small intestine in response to ischemia/ reperfusion injury. METHODS： Forty-seven Sprague-Dawley rats with body weight of 250-300 g were divided into two groups： control group （sham shock n = 5） and experimental group （n = 42）. Experimental group was further divided into six groups （n = 7 each） according to different time points after the hemorrhagic shock, including 0^th group, 1^st group, 3^rd group, 6th h group, 12^th group and 24^th group. All the rats were gavaged with 2 mL of suspension of lactulose （L） （100 mg/2 mL） and mannitol （M） （50 mg/each） at the beginning and then an experimental rat model of hemorrhagic shock was set up. The specimens from jejunum, ileum and colon tissues and the blood samples from the portal vein were taken at 0, 1, 3, 6, 12 and 24 h after shock resuscitation, respectively. The morphological changes of the intestinal mucosa, including the histology of intestinal mucosa, the thickness of mucosa, the height of villi, the index of mucosal damage and the numbers of goblet cells, were determined by light microscope and/or electron microscope. The concentrations of the bacterial endotoxin lipopolysaccharides （LPS） from the portal vein blood, which reflected the gut barrier function, were examined by using Limulus test. At the same time point, to evaluate intestinal permeability, all urine was collected and the concentrations of the metabolically inactive markers such as L and M in urine were measured by using GC-9A gas chromatographic instrument.RESULTS： After the hemorrhagic shock, the mucosal epithelial injury was obvious in small intestine even at the 0th h, and it became more serious at the 1^stand the 3^rd h. The tissue restitution was also found after 3 h, though the injury was still serious. Most of the injured mucosal restitution was established after 6 h and completed in 24 h. Two distinct models of cell deathapoptosis and necrosis-were involved in the destruction of rat intestinal epithelial cells. The number of goblet cells on intestinal mucosa was reduced significantly from 0 to 24 h （the number from 243±13 to 157±9 for ileum, 310±19 to 248±18 for colon; r= -0.910 and -0.437 respectively, all P〈0.001）, which was the same with the large intestine, but the grade of injury was lighter with the values of mucosal damage index in 3 h for jejunum, ileum, and colon being 2.8, 2.6, 1.2, respectively. The mucosal thickness and the height of villi in jejunum and ileum diminished in 1 h （the average height decreased from 309±24 to 204±23 pm and 271±31 to 231±28 pm, r = -0.758 and -0.659, all P〈0.001, the thickness from 547±23 to 418±28μm and 483±45 to 364±35μm, r= -0.898 and -0.829, all P〈0.001）, but there was no statistical difference in the colon （F= 0.296, P = 0.934）. Compared with control group, the urine L/M ratio and the blood LPS concentration in the experimental groups raised significantly, reaching the peak in 3-6 h （L/M： control vs 3 h vs6 h was 0.029±0.09 vs 0.063±0.012 vs 0.078±0.021, r = -0.786, P〈0.001; LPS： control vs3 h vs6 h was 0.09±0.021 vs 0.063±0.012 vs0.25±0.023, r=- -0.623, P〈0.001）, and it kept increasing in 24 h. CONCLUSION： The gut barrier of the rats was seriously damaged at the early phase of ischemic reperfusion injury after hemorrhagic shock, which included the injury and atrophy in intestinal mucosa and the increasing of intestinal permeability. Simultaneously, the intestinal mucosa also showed its great repairing potentiality, such as the improvement of the intestinal permeability and the recovery of the morphology at different phases after ischemic reperfusion injury. The restitution of gut barrier function was obviously slower than that of the morphology and there was no direct correlation between them. Compared with the small intestine, the large intestine had stronger potentiality against injury. The reduction of the amount of intestinal goblet cells by injury did not influence the ability of intestinal mucosal restitution at a certain extent and it appeared to be intimately involved in the restitution of the epithelium.

Gut barrier failure biomarkers are associated with poor disease outcome in patients with primary sclerosing cholangitis

To assess the prevalence of a panel of serologic markers that reflect gut barrier dysfunction in a mixed cohort of pediatric and adult primary sclerosing cholangitis (PSC) patients. METHODSSera of 67 PSC patients [median age (range): 32 (5-79) years, concomitant IBD: 67% and cirrhosis: 20%] were assayed for the presence of antibodies against to F-actin (AAA IgA/IgG) and gliadin (AGA IgA/IgG)] and for serum level of intestinal fatty acid-binding protein (I-FABP) by ELISA. Markers of lipopolysaccharide (LPS) exposure [LPS binding protein (LBP)] and various anti-microbial antibodies [anti-OMP Plus IgA and endotoxin core IgA antibody (EndoCAb)] were also determined. Poor disease outcome was defined as orthotopic liver transplantation and/or liver-related death during the follow-up [median: 99 (14-106) mo]. One hundred and fifty-three healthy subjects (HCONT) and 172 ulcerative colitis (UC) patients were the controls. RESULTSA total of 28.4%, 28.0%, 9% and 20.9% of PSC patients were positive for AAA IgA, AAA IgG, AGA IgA and AGA IgG, respectively. Frequencies of AAA IgA and AAA IgG (P < 0.001, for both) and AGA IgG (P = 0.01, for both) but not AGA IgA were significantly higher compared to both of the HCONT and the UC groups. In survival analysis, AAA IgA-positivity was revealed as an independent predictor of poor disease outcome after adjusting either for the presence of cirrhosis [HR = 5.15 (1.27-20.86), P = 0.022 or for the Mayo risk score (HR = 4.24 (0.99-18.21), P = 0.052]. AAA IgA-positivity was significantly associated with higher frequency of anti-microbial antibodies (P < 0.001 for EndoCab IgA and P = 0.012 for anti-OMP Plus IgA) and higher level of the enterocyte damage marker (median I-FABPAAA IgA posvsneg: 365 vs 166 pg/mL, P = 0.011), but not with serum LBP level. CONCLUSIONPresence of IgA type AAA identified PSC patients with progressive disease. Moreover, it is associated with enhanced mucosal immune response to various microbial antigens and enterocyte damage further highlighting the importance of the gut-liver interaction in PSC.

GUT BARRIER FUNCTION DAMAGE FOLLOWING MULTIPLE FIREARM INJURIES IN A PORCINE MODEL

Objective. To study the characteristics and pathogenesis of gut barrier damage following multiple firearm injuries in a porcine model. Methods. Twenty four small pigs were divided into 4 groups: control group (n=6, group C), group H (n=6, gunshot induced tangential fracture of parietal bone), group L (n=6, gunshot induced comminuted fracture of bilateral femora) and group M (n=6, combined group H+L). Gastric intramucosal pH (pHi), plasma endotoxin levels in portal vein, and plasma D lactate levels were measured and blood samples were cultured at different intervals after trauma. The animals were sacrificed at 72 h following trauma and intestinal tissues were harvested for pathological examination and diamine oxidase (DAO) activity measurement. Results. In group M at 72 h, pHi was significantly lower than that of group H and L (P< 0.01), and plasma endotoxin level was significantly higher than that of group H (P< 0.01) and group L (P< 0.05). Simultaneously, in groupM, D lactate level was markedly higher than that of group H (P< 0.01), and incidence of positive blood culture was much higher than that of group H and L (P<0.05). Necrosis and exfoliation were revealed at ileum villus top in all traumagroups, especially in group M, in which ileum DAO activity declined most significantly as well. Conclusion. Multiple trauma is prone to cause gastrointestinal ischemia even without hemorrhagic shock. The damage of gut barrier in multiple trauma appears to be more severe than that in one site trauma, thereby promoting gut derived endotoxemia and bacterial translocation and contributing to the development of endogenous infection.SURGICAL TREATMENT OF MALIGNANTESOPHAGEAL TUMORS IN PUMC HOSPITAL Guo Huiqin,Li Zejian ,Zhang Fan1 ,Zhang Zhiyong,Xu Letian ,Li Weidong2,Wang Xiuqin2and Wu Min2Department of Thoracic Surgery, PUMC Hospital, CAMS &PUMC, Beijing 100730Key words malignant esophageal tumors; early diagnosis; FHIT geneTo study how to prolong the postoperative survival time of the patientswith malignant esophageal tumors. The clinical data of 1098 patients with malignant esophageal tumors from 1961 to 1992 were retrospectively analyzed. The deletion of fragile histamine triplet (FHIT) gene (a tumor suppressor gene) in 30 fresh esophageal samples obtained in 1996 was detected with PCR and RT PCR method. The resectability was raised gradually and the operative morbidity and mortality decreased year by year, but there was no significant improvement on the postoperative 5 year survival rate. Delayed diagnosis and irradical resection influenced the long term survival. The deletion of cDNA of FHIT gene was 64.2%in esophageal cancer and 20%in the resected margin of the cancer. We believe that high grade atypical hyperplasia in esophageal epithelium and deletion of FHIT gene in esophageal cancer and its resected margin are pathological and molecular markers for early diagnosis of esophageal cancer respectively, and the latter may be one of the molecular markers for the resection. Early diagnosis and treatment, radical resection, and postoperative nutritional support are very important for the improvement of the postoperative survival time of the patients.

Taurine Protects Gut Barrier Function and Prevents Endothelial Cell Injury Induced by Ischaemia-Reperfusion

Purpose: Gut permeability and microvascular injury following ischaemia/reperfusion (IR) have been implicated in the systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF). Taurine (TAU), a sulfur-containing amino acid, is a powerful antioxidant and regulator of intracellular calcium and several studies have established that treatment with TAU protects cerebral, cardiac and testicular tissue from (IR) injury. This study investigates the protective effect of taurine in an experimental model of I/R-induced gut injury in rats. Methods: Sprague-Dawley rats were randomized into three groups: Control, I/R, TAU + I/R. TAU was given by gavage or intravenous injection before I/R. Ischaemia was induced by cross-clamping superior mesenteric and coeliac vascular pedicle for 20 - 30 min, followed by 60 - 180 min reperfusion. Gut permeability, blood flux, tissue oedema, leucocytes infiltration and eNOS expression were measured at 3 hrs following reperfusion using FD4. Leukocyte-endothelial interactions were determined by intra-vital microscopy during I/R. In vitro studies assessed the protective effect of TAU on endothelial cell function and survival. Results: Treatment with TAU significantly attenuated IR-induced gut hyper permeability, tissue oedema, leukocyte adhesion and infiltration. TAU also prevented the reduction in gut blood flow, leukocyte rolling velocity and eNOS expression induced by IR. TAU protects against I/R-induced endothelial cell injury by reduced anti-oxidant activity and modulation of eNOS expression and intracellular calcium fluxes. Conclusions: TAU protects the gut from intestinal barrier dysfunction induced by surgical I/R.

Elafibranor:A promising therapeutic approach for liver fibrosis and gut barrier dysfunction in alcohol-associated liver disease

This article discusses the recent study written by Koizumi et al.Alcohol-associated liver disease(ALD)is a major cause of liver-related morbidity and mortality,which is driven by complex mechanisms,including lipid accumulation,apoptosis,and inflammatory responses exacerbated by gut barrier dysfunction.The study explored the therapeutic potential of elafibranor,a dual peroxisome proliferatoractivated receptor alpha/delta agonist.In clinical trials,elafibranor has shown promise for the treatment of other liver conditions;however,its effects on ALD remain unclear.The authors’findings indicate that elafibranor significantly reduced liver fibrosis and enhanced gut barrier integrity in patients with ALD.These positive effects of elafibranor are mediated through multiple pathways.Elafibranor promotes lipid metabolism,reduces oxidative stress,and inhibits inflammatory responses by restoring gut barrier function.Specifically,it improves hepatocyte function by enhancing autophagic and antioxidant capacity,and it mitigates inflammation by suppressing the lipopolysaccharide/toll-like receptor 4/nuclear factor kappa B signaling pathway.These findings indicate that elafibranor has promising clinical applications.In addition,the study highlights elafibranor’s potential as a therapeutic agent for liver diseases,particularly ALD.This article underscores the importance of understanding the mechanistic pathways underlying ALD and suggests directions for future research aimed at elucidating the benefits and limitations of elafibranor.

High-fat diet impairs gut barrier through intestinal microbiota-derived reactive oxygen species

Gut barrier disruption is a key event in bridging gut microbiota dysbiosis and high-fat diet(HFD)-associated metabolic disorders.However,the underlying mechanism remains elusive.In the present study,by comparing HFD-and normal diet(ND)-treated mice,we found that the HFD instantly altered the composition of the gut microbiota and subsequently damaged the integrity of the gut barrier.Metagenomic sequencing revealed that the HFD upregulates gut microbial functions related to redox reactions,as confirmed by the increased reactive oxygen species(ROS)levels in fecal microbiota incubation in vitro and in the lumen,which were detected using in vivo fluorescence imaging.This microbial ROS-producing capability induced by HFD can be transferred through fecal microbiota transplantation(FMT)into germ-free(GF)mice,downregulating the gut barrier tight junctions.Similarly,mono-colonizing GF mice with an Enterococcus strain excelled in ROS production,damaged the gut barrier,induced mitochondrial malfunction and apoptosis of the intestinal epithelial cells,and exacerbated fatty liver,compared with other low-ROS-producing Enterococcus strains.Oral administration of recombinant high-stability-superoxide dismutase(SOD)significantly reduced intestinal ROS,protected the gut barrier,and improved fatty liver against the HFD.In conclusion,our study suggests that extracellular ROS derived from gut microbiota play a pivotal role in HFD-induced gut barrier disruption and is a potential therapeutic target for HFD-associated metabolic diseases.

Influences of enteral nutrition combined with probiotics on gut microflora and barrier function of rats with abdominal infection

AIM： To investigate the influences of enteral, parenteral nutrition and probiotics delivered by gut on intestinal microecology, epithelial tight junctions, immune and barrier function of rats with abdominal infection. METHODS： Rat abdominal infection models established with cecal ligation and perforation method, were divided into three groups： parenteral nutrition （PN group, n = 7）, PN＋enteral nutrition （EN group, n = 7） and PN ＋ EN ＋ probiotics （probiotics group, n = 7） via the needle jejunostomy and neck vein for five days. The total nutritional supplement of the three groups was isonitrogenic and isocaloric. Probiotics was delivered by jejunostomy 10 mL/d （1 x 10^8 cfu/mL）. The rats were killed on the sixth day. The feces in the cecum were cultured for anaerobic bacterial growth and analyzed with bacterial group DNA fingerprint profile with random amplified polymorphic DNA. The transmembrane binding proteins （occludin） and IgA level in plasma cells of intestine epithelium in colon and terminal ileum were measured by an immunohistochemistry method. The ultrastructure of intestinal epithelial tight junctions in colon and small intestine was observed by electronmicroscopy. Vena cava blood and the homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine the bacterial translocations, and endotoxin in the blood from portal vein was detected. RESULTS： （1） The amount of bacteria of gut species in EN group and probiotic group was higher than that in PN group. The DNA-proflles in EN group and probiotic group were similar to that of normal rats. The number of DNAprofiles in probiotics group was much more than that in PN group and EN group. Moreover, there were strange stripes in PN group. （2） The expression of occludin and IgA in the small and large intestine in EN group （2.309 ± 0.336, 15.440 ± 2.383） and probiotic group （2.938 ± 0.515, 16.230 ± 3.183） was improved as compared with PN group （1.207 ± 0.587, P 〈 0.05, 11.189 ± 2.108, P 〈 0.01）. The expression of occludin in probiotic group （intestine： 2.93 ± 0.515; cecum： 3.40 ± 0.617） was higher than that in EN group （intestine： 2.309 ± 0.336; cecum： 2.076 ± 0.670; P 〈 0.05）. The expression of IgA, especially in EN group （intestine： 15.440 ± 2.383） and probiotic EN group （large intestine： 12.516 ± 1.542） significantly increased as compared with PN group （intestine： 11.189 ± 2.108; cecum： 10.160 ± 1.643; P 〈 0.01）. The intestinal epithelial tight junctions and microvilli of the probiotic group were more intact than those in the PN group. （3） The bacterial translocations in blood, liver, lung and mesenteric lymph nodes, and the levels of endotoxin were significantly reduced in probiotic （0.082 ± 0.029） and EN （0.125 ± 0.040） groups as compared with PN group （0.403 ± 0.181, P 〈 0.05）. CONCLUSION： Application of EN combined with probiotics could improve the expression of transmembrane binding proteins （occludin） and IgA, correct the intestinal flora disturbance, maintain gut barrier functions and tight junctions, and reduce the occurrence of gut bacterial translocation.

Dietary ferulic acid and vanillic acid on inflammation,gut barrier function and growth performance in lipopolysaccharide-challenged piglets

Ferulic acid(FA)and vanillic acid(VA)are considered as major phenolic metabolites of cyanidin 3-glucoside,a polyphenol that widely exists in plants that possess a protective effect against oxidative stress and inflammation in our previous study.This study aimed to investigate the effect of FA and VA on inflammation,gut barrier function,and growth performance in a weaned piglet model challenged with lipopolysaccharide(LPS).Thirty-six piglets(PIC 337×C48,28 d of age)were randomly allocated into 3 treatments with 6 replicate pens(2 piglets per pen).They were fed with a basal diet or a diet containing 4,000 mg/kg of FA or VA.Dietary supplementation of VA significantly increased average daily gain(ADG)(P<0.05).Both FA and VA decreased serum levels of thiobarbituric acid reactive substances(TBARS),interlukin(IL)-1β,IL-2,IL-6,and tumor necrosis factor(TNF)-α(P<0.05),and enhanced the expression of tight junction protein oclaudin(P<0.05).Analysis of gut microbiota indicated that both FA and VA increased the Firmicutes/Bacteroidetes ratio alongside reducing the relative abundance of the Prevotellaceae family including Prevotella 9 and Prevotella 2 genera,but enriched the Lachoiraceaea family including the Lachnospiraceae FCS020 group(P<0.05).Moreover,VA reduced the relative abundance of Prevotella 7 and Prevotella 1 but enriched Lachnospira,Eubacterium eligens group,and Eubacterium xylanophilum group(P<0.05),while FA showed a limited effect on these genera.The results demonstrated that both VA and FA could alleviate inflammation and oxidative stress,but only VA has a significant positive effect on the growth performance of LPS-challenged piglets potentially through modulating gut microbiota.

The direct and gut microbiota-mediated effects of dietary bile acids on the improvement of gut barriers in largemouth bass(Micropterus salmoides)

Fish gut barrier damage under intensive culture model is a significant concern for aquaculture industry.This study aimed to investigate the effects of bile acids(BAs)on gut barriers in Micropterus salmoides.A germ-free(GF)zebrafish model was employed to elucidate the effects of the direct stimulation of BAs and the indirect regulations mediated by the gut microbiota on gut barrier functions.Four diets were formulated with BAs supplemented at 0,150,300 and 450 mg/kg,and these 4 diets were defined as control,BA150,BA300 and BA450,respectively.After 5 weeks of feeding experiment,the survival rate of fish fed with BA300 diet was increased(P<0.05).Histological analysis revealed an improvement of gut structural integrity in the BA150 and BA300 groups.Compared with the control group,the expression of genes related to chemical barrier(mucin,lysozyme and complement 1)and physical barrier(occludin and claudin-4)was increased in the BA150 and BA300 groups(P<0.05),and the expression of genes related to immunological barrier(interleukin[IL]-6,tumor growth factorβ,IL-10,macrophage galactosetype lectin and immunoglobulin M[Ig M])was significantly increased in the BA300 group(P<0.05),but the expression of genes related to chemical barrier(hepcidin)and immunological barrier(IL-1β,tumor necrosis factor-a,IL-6 and arginase)was significantly decreased in the BA450 group(P<0.05).Gut microbiota composition analysis revealed that the abundance of Firmicutes was augmented prominently in the BA150 and BA300 groups(P<0.05),while that of Actinobacteriota and Proteobacteria showed a downward trend in the BA150 and BA300 groups(P>0.05).The results of the gut microbiota transferring experiment demonstrated an upregulation of gut barrier-related genes,including immunoglobulin Z/T(Ig Z/T),IL-6,IL-1βand IL-10,by the gut microbiota transferred from the BA300 group compared with the control(P<0.05).Feeding the BA300 diet directly to GF zebrafish resulted in enhanced expression of Ig M,Ig Z/T,lysozyme,occludin-2,IL-6 and IL-10(P<0.05).In conclusion,BAs can improve the gut barriers of fish through both direct and indirect effects mediated by the gut microbiota.

Targeting the gut barrier for the treatment of alcoholic liver disease

Alcohol consumption remains one of the predominant causes of liver disease and liver-related death worldwide.Intriguingly,dysregulation of the gut barrier is a key factor promoting the pathogenesis of alcoholic liver disease(ALD).A functional gut barrier,which consists of a mucus layer,an intact epithelial monolayer and mucosal immune cells,supports nutrient absorption and prevents bacterial penetration.Compromised gut barrier function is associated with the progression of ALD.Indeed,alcohol consumption disrupts the gut barrier,increases gut permeability,and induces bacterial translocation both in ALD patients and in experimental models with ALD.Moreover,alcohol consumption also causes enteric dysbiosis with both numerical and proportional perturbations.Here,we review and discuss mechanisms of alcohol-induced gut barrier dysfunction to better understand the contribution of the gut-liver axis to the pathogenesis of ALD.Unfortunately,there is no effectual Food and Drug Administration-approved treatment for any stage of ALD.Therefore,we conclude with a discussion of potential strategies aimed at restoring the gut barrier in ALD.The principle behind antibiotics,prebiotics,probiotics and fecal microbiota transplants is to restore microbial symbiosis and subsequently gut barrier function.Nutrientbased treatments,such as dietary supplementation with zinc,niacin or fatty acids,have been shown to regulate tight junction expression,reduce intestinal inflammation,and prevent endotoxemia as well as liver injury caused by alcohol in experimental settings.Interestingly,saturated fatty acids may also directly control the gut microbiome.In summary,clinical and experimental studies highlight the significance and efficacy of the gut barrier in treating ALD.

Probiotic Pediococcus pentosaceus restored gossypol-induced intestinal barrier injury by increasing propionate content in Nile tilapia

Background Intestinal barrier is a dynamic interface between the body and the ingested food components, however, dietary components or xenobiotics could compromise intestinal integrity, causing health risks to the host. Gossypol, a toxic component in cottonseed meal(CSM), caused intestinal injury in fish or other monogastric animals. It has been demonstrated that probiotics administration benefits the intestinal barrier integrity, but the efficacy of probiotics in maintaining intestinal health when the host is exposed to gossypol remains unclear. Here, a strain(YC) affiliated to Pediococcus pentosaceus was isolated from the gut of Nile tilapia(Oreochromis niloticus) and its potential to repair gossypol-induced intestinal damage was evaluated.Results A total of 270 Nile tilapia(2.20 ± 0.02 g) were allotted in 3 groups with 3 tanks each and fed with 3 diets including CON(control diet), GOS(control diet containing 300 mg/kg gossypol) and GP(control diet containing 300 mg/kg gossypol and 10^(8) colony-forming unit(CFU)/g P. pentosaceus YC), respectively. After 10 weeks, addition of P. pentosaceus YC restored growth retardation and intestinal injury induced by gossypol in Nile tilapia. Transcriptome analysis and si RNA interference experiments demonstrated that NOD-like receptors(NLR) family caspase recruitment domain(CARD) domain containing 3(Nlrc3) inhibition might promote intestinal stem cell(ISC) proliferation, as well as maintaining gut barrier integrity. 16S r RNA sequencing and gas chromatography-mass spectrometry(GC-MS) revealed that addition of P. pentosaceus YC altered the composition of gut microbiota and increased the content of propionate in fish gut. In vitro studies on propionate's function demonstrated that it suppressed nlrc3 expression and promoted wound healing in Caco-2 cell model.Conclusions The present study reveals that P. pentosaceus YC has the capacity to ameliorate intestinal barrier injury by modulating gut microbiota composition and elevating propionate level. This finding offers a promising strategy for the feed industry to incorporate cottonseed meal into fish feed formulations.

Junshanyinzhen tea extract prevents obesity by regulating gut microbiota and metabolic endotoxemia in high-fat diet fed rats

Obesity is associated with gut dysbiosis and metabolic endotoxin.Junshanyinzhen tea extract(JSTE)reduced fat accumulation and body weight in obese mice.However,the effects and mechanism of JSTE in preventing obesity were unclear.Therefore,we used different doses of JSTE(75,150 and 300 mg/(kg·day))to evaluate the effect on high-fat diet(HFD)-induced rats under 8 weeks of intervention.Here,our results showed that JSTE could significantly reduce body weight gain,blood lipid levels and fat accumulation,improve fatty damage in liver tissue(P<0.05).In addition,JSTE increased the expression of intestinal tight junction proteins(P<0.05),relieved metabolic endotoxemia(P<0.05)and chronic low-grade inflammation in HFD rats.Sequencing of fecal samples showed that JSTE could effectively reverse the microbial diversity and the ratio of Firmicutes to Bacteroidetes to normal levels in HFD-fed rats.Desulfovibrioceae and Erysipelotrichaceae,which are positively related to obesity,were decreased by JSTE intervention(P<0.05).while Bifidobacteriaceae,Bacteroidaceae,Akkermansia,and Clostridium,which are negatively related to obesity,were increased.Together,these results suggested that JSTE might effectively prevent obesity by modulating gut microbiota dysbiosis,intestinal barrier dysfunction,metabolic endotoxemia and chronic low-grade infl ammation in HFD-induced rats.

Elafibranor alleviates alcohol-related liver fibrosis by restoring intestinal barrier function

We discuss the article by Koizumi et al published in the World Journal of Gastroenterology.Our focus is on the therapeutic targets for fibrosis associated with alcohol-related liver disease(ALD)and the mechanism of action of elafibranor(EFN),a dual agonist of peroxisome proliferator-activated receptorα(PPARα)and peroxisome PPARδ(PPARδ).EFN is currently in phase III clinical trials for the treatment of metabolic dysfunction-associated fatty liver disease and primary biliary cholangitis.ALD progresses from alcoholic fatty liver to alcoholic steatohepatitis(ASH),with chronic ASH eventually leading to fibrosis,cirrhosis,and,in some cases,hepatocellular carcinoma.The pathogenesis of ALD is driven by hepatic steatosis,oxidative stress,and acetaldehyde toxicity.Alcohol consumption disrupts lipid metabolism by inactivating PPARα,exacerbating the progression of ALD.EFN primarily activates PPARα,promoting lipolysis andβ-oxidation in ethanol-stimulated HepG2 cells,which significantly reduces hepatic steatosis,apoptosis,and fibrosis in an ALD mouse model.Additionally,alcohol disrupts the gut-liver axis at several interconnected levels,contributing to a proinflammatory environment in the liver.EFN helps alleviate intestinal hyperpermeability by restoring tight junction protein expression and autophagy,inhibiting apoptosis and inflammatory responses,and enhancing intestinal barrier function through PPARδactivation.

Gut microbiota remodeling drived by dietary millet protein prevents the metabolic syndrome

Metabolic syndrome(Met S)is a chronic disease associated with the disturbance of gut microbiota homeostasis.Metabolites derived from gut microbes play essential roles in Met S prevention and therapy.Here,we focused on the inhibitory effect of the extract of millet bran protein(EMBP)on a high-fat diet(HFD)-induced Met S,aiming to identify gut microbiota and their metabolites that involve in the anti-Met S activity of EMBP.The obesity,chronic inflammation,insulin resistance in Met S mouse models were abolished after EMBP treatment.The protective mechanism of EMBP against HFD-induced Met S may depend on improved gut barrier function.Using microbiome analysis,we found that EMBP supplementation improved gut microbiome dysbiosis in Met S mice,specifically upregulating Bacteroides acidifaciens.The fecal microbiota transplantation(FMT)also demonstrated this phenomenon.In addition,metabolomic analysis showed that EMBP mediates metabolic profiling reprogramming in Met S mice.Notably,a microbiota-derived metabolite,gamma-aminobutyric acid(GABA),is enriched by EMBP.In addition,exogenous GABA treatment produced a similar protective effect to EMBP by improving NRF2-dependent gut barrier function to protect HFDinduced Met S.The results suggest that EMBP suppress host Met S by remodeling of gut microbiota as an effective candidate for next-generation medicine food dual purpose dietary supplement to intervene in MetS.

Gut epithelial barrier dysfunction in humanimmunodeficiency virus-hepatitis C virus coinfectedpatients:Influence on innate and acquired immunity

Even in cases where viral replication has been controlled by antiretroviral therapy for long periods of time, human immunodeficiency virus(HIV)-infected patients have several non-acquired immunodeficiency syndrome(AIDS) related co-morbidities, including liver disease, cardiovascular disease and neurocognitive decline, which have a clear impact on survival. It has been considered that persistent innate and acquired immune activation contributes to the pathogenesis of these non-AIDS related diseases. Immune activation has been related with several conditions, remarkably with the bacterial translocation related with the intestinal barrier damage by the HIV or by hepatitis C virus(HCV)-related liver cirrhosis. Consequently, increased morbidity and mortality must be expected in HIV-HCV coinfected patients. Disrupted gut barrier lead to an increased passage of microbial products and to an activation of the mucosal immune system and secretion of inflammatory mediators, which in turn might increase barrier dysfunction. In the present review, the intestinal barrier structure, measures of intestinal barrier dysfunction and the modifications of them in HIV monoinfection and in HIV-HCV coinfection will be considered. Both pathogenesis and the consequences for the progression of liver disease secondary to gut microbial fragment leakage and immune activation will be assessed.

Broiler gut microbiota and expressions of gut barrier genes affected by cereal type and phytogenic inclusion

The present study assessed the effects of cereal type and the inclusion level of a phytogenic feed additive(PFA) on broiler ileal and cecal gut microbiota composition, volatile fatty acids(VFA) and gene expression of toll like receptors(TLR), tight junction proteins, mucin 2(MUC2) and secretory immunoglobulin A(sIgA). Depending on cereal type(i.e. maize or wheat) and PFA inclusion level(i.e. 0, 100 and 150 mg/kg diet), 450 one-day-old male broilers were allocated in 6 treatments according to a 2 × 3 factorial arrangement with 5 replicates of 15 broilers each, for 42 d. Significant interactions(P 0.05) between cereal type and PFA were shown for cecal digesta Bacteroides and Clostridium cluster XIVa, ileal digesta propionic and branched VFA, ileal s IgA gene expression, as well as cecal digesta branched and other VFA molar ratios. Cereal type affected the cecal microbiota composition. In particular, wheat-fed broilers had higher levels of mucosa-associated Lactobacillus(P_(CT)= 0.007) and digesta Bifidobacterium(P_(CT)< 0.001),as well as lower levels of total bacteria(P_(CT)= 0.004) and Clostridia clusters I, IV and XIVa(P_(CT) 0.05),compared with maize-fed ones. In addition, cereal type gave differences in fermentation intensity(P_(CT)= 0.021) and in certain individual VFA molar ratios. Wheat-fed broilers had higher(P 0.05) ileal zonula occluden 2(ZO-2) and lower ileal and cecal TLR2 and sIgA levels, compared with maize-fed broilers. On the other hand, PFA inclusion at 150 mg/kg had a stimulating effect on microbial fermentation at ileum and a retarding effect in ceca with additional variable VFA molar patterns. In addition, PFA inclusion at 100 mg/kg increased the ileal mucosa expression of claudin 5(CLDN5)(PPFA= 0.023) and MUC2(PPFA= 0.001) genes, and at 150 mg/kg decreased cecal TLR2(PPFA= 0.022) gene expression compared with the un-supplemented controls. In conclusion, cereal type and PFA affected in combination and independently broiler gut microbiota composition and metabolic activity as well as the expression of critical gut barrier genes including TLR2. Further exploitation of these properties in cases of stressor challenges is warranted.

Focus on the gut-brain axis: multiple sclerosis, the intestinal barrier and the microbiome

The brain-gut axis serves as the bidirectional connection between the gut microbiome, the intestinal barrier and the immune system that might be relevant for the pathophysiology of inflammatory demyelinating diseases. People with multiple sclerosis have been shown to have an altered microbiome, increased intestinal permeability and changes in bile acid metabolism. Experimental evidence suggests that these changes can lead to profound alterations of peripheral and central nervous system immune regulation. Besides being of pathophysiological interest, the brain-gut axis could also open new avenues of therapeutic targets. Modification of the microbiome, the use of probiotics, fecal microbiota transplantation, supplementation with bile acids and intestinal barrier enhancers are all promising candidates. Hopefully, pre-clinical studies and clinical trials will soon yield significant results.

Supplementation of a lacto-fermented rapeseed-seaweed blend promotes gut microbial-and gut immune-modulation in weaner piglets

Background:The direct use of medical zinc oxide in feed will be abandoned after 2022 in Europe,leaving an urgent need for substitutes to prevent post-weaning disorders.Results:This study investigated the effect of using rapeseed-seaweed blend(rapeseed meal added two brown macroalgae species Ascophylum nodosum and Saccharina latissima)fermented by lactobacilli(FRS)as feed ingredients in piglet weaning.From d 28 of life to d 85,the piglets were fed one of three different feeding regimens(n=230 each)with inclusion of 0%,2.5% and 5% FRS.In this period,no significant difference of piglet performance was found among the three groups.From a subset of piglets(n=10 from each treatment),blood samples for hematology,biochemistry and immunoglobulin analysis,colon digesta for microbiome analysis,and jejunum and colon tissues for histopathological analyses were collected.The piglets fed with 2.5% FRS manifested alleviated intraepithelial and stromal lymphocytes infiltration in the gut,enhanced colon mucosa barrier relative to the 0% FRS group.The colon microbiota composition was determined using V3 and V1-V8 region 16S rRNA gene amplicon sequencing by Illumina NextSeq and Oxford Nanopore MinION,respectively.The two amplicon sequencing strategies showed high consistency between the detected bacteria.Both sequencing strategies indicated that inclusion of FRS reshaped the colon microbiome of weaned piglets with increased Shannon diversity.Prevotella stercorea was verified by both methods to be more abundant in the piglets supplied with FRS feed,and its abundance was positively correlated with colonic mucosa thickness but negatively correlated with blood concentrations of leucocytes and IgG.Conclusions:FRS supplementation relieved the gut lymphocyte infiltration of the weaned piglets,improved the colon mucosa barrier with altered microbiota composition.Increasing the dietary inclusion of FRS from 2.5% to 5% did not lead to further improvements.

Probiotics and gut health:A special focus on liver diseases

Probiotic bacteria have well-established beneficial ef-fects in the management of diarrhoeal diseases.Newer evidence suggests that probiotics have the potential to reduce the risk of developing inflammatory bowel diseases and intestinal bacterial overgrowth after gut surgery.In liver health,the main benefits of probiotics might occur through preventing the production and/or uptake of lipopolysaccharides in the gut,and therefore reducing levels of low-grade inflammation.Specific immune stimulation by probiotics through processes involving dendritic cells might also be beneficial to the host immunological status and help prevent pathogen translocation.Hepatic fat metabolism also seems to be influenced by the presence of commensal bacteria,and potentially by probiotics;although the mechanisms by which probiotic might act on the liver are still unclear.However,this might be of major importance in the fu-ture because low-grade inflammation,hepatic fat infil-tration,and hepatitis might become more prevalent as a result of high fat intake and the increased prevalence of obesity.