Retinol is involved in the intestinal regeneration and strengthens the intestinal barrier during refeeding in broiler chickens

Fasting is typically used before feeding metabolizable energy assessment in broilers.Previous studies have shown that fasting cause atrophy of the intestinal villus.Whether fasting affects intestinal permeability during refeeding by altering barrier function and nutrient absorption is of concern.Here,23-d-old broilers were randomly assigned to 5 treatments,fasted for 0,12,24,36,and 48 h,respectively,and then refed for 2 d,to study the impact of different duration of fasting on the intestinal regeneration and barrier function during refeeding.Results showed that the intestinal morphology in fasted birds was recovered in 2 d of refeeding at most.As fasting durations increased,enterocytes per intestinal villus were linearly and quadratically increased(both P<0.05),whereas goblet cells per intestinal villus was linearly decreased(both P<0.05).Besides,the mRNA level of lysozyme was linearly decreased as fasting durations increased during refeeding(both P<0.05),while quadratically increased mucin 2 was observed only after 1 d of refeeding(P<0.05).Linear increase effects were observed for claudin 2 and zonula occludens-1with increased fasting durations after 1 d of refeeding(all P<0.05),and linear and quadratical effects were observed for claudin 2 at 2 d of refeeding(both P<0.05).Besides,we found that intestinal permeability to creatinine,4 and 70 kD dextran were linearly and quadratically decreased with increased fasting durations at 6 h and 1 d of refeeding(all P<0.05).Furthermore,jejunum proteomic from birds refed for 6 h showed that birds fasted for 36 h showed increased antimicrobial peptides and upregulated retinol metabolism when compared to the nonfasted birds(P<0.05).Further study showed that retinyl ester catabolism was inhibited during fasting and enhanced during refeeding.Results of intestinal organoid culture showed that retinol benefits the cell proliferation and enterocyte differentiation.In conclusion,the intestinal permeability to small and large molecules was decreased during refeeding by strengthening the intestinal barrier function,and the activated retinol metabolism during refeeding is involved in the intestinal regeneration and strengthens the intestinal barrier.

Damage on intestinal barrier function and microbial detoxification of deoxynivalenol:A review

Deoxynivalenol(DON)is a mycotoxin that is produced by various species of Fusarium and is ubiquitous in food and feed.At low concentrations,it can cause metabolic disorders in animals and humans and,at high concentrations,it can lead to pathological changes in the body.The impact of DON on human/animal health and animal productivity has thus attracted a great deal of attention around the world.DON causes severe damage to the intestine,including compromised intestinal barrier,mucosal damage,weakened immune function,and alterations in gut microbiota composition.These effects exacerbate intestinal infections and inflammation in livestock and poultry,posing adverse effects on overall health.Furthermore,research into biological methods for DON detoxification is a crucial avenue for future studies.This includes the utilization of adsorption,enzymatic degradation,and other biological approaches to mitigate DON's impact,offering new strategies for prevention and treatment of DON-induced diseases.Future research will focus on identifying highly efficient detoxifying microorganisms or enzymes to reduce DON levels in food and feed,thereby mitigating its risks to both animals and human health.

Effects of Enteromorpha prolifera polysaccharides on growth performance,intestinal barrier function and cecal microbiota in yellow-feathered broilers under heat stress

Background Global warming leading to heat stress(HS)is becoming a major challenge for broiler production.This study aimed to explore the protective effects of seaweed(Enteromorpha prolifera)polysaccharides(EPS)on the intestinal barrier function,microbial ecology,and performance of broilers under HS.A total of 144 yellow-feathered broilers(male,56 days old)with 682.59±7.38 g were randomly assigned to 3 groups:1)TN(thermal neutral zone,23.6±1.8℃),2)HS(heat stress,33.2±1.5℃ for 10 h/d),and 3)HSE(HS+0.1%EPS).Each group contained 6 replicates with 8 broilers per replicate.The study was conducted for 4 weeks;feed intake and body weights were measured at the end of weeks 2 and 4.At the end of the feeding trial,small intestine samples were collected for histomorphology,antioxidant,secretory immunoglobulin A(s Ig A)content,apoptosis,gene and protein expression analysis;cecal contents were also collected for microbiota analysis based on 16S r DNA sequencing.Results Dietary EPS promoted the average daily gain(ADG)of broilers during 3–4 weeks of HS(P<0.05).At the end of HS on broilers,the activity of total superoxide dismutase(T-SOD),glutathione S-transferase(GST),and the content of s Ig A in jejunum were improved by EPS supplementation(P<0.05).Besides,dietary EPS reduced the epithelial cell apoptosis of jejunum and ileum in heat-stressed broilers(P<0.05).Addition of EPS in HS group broilers'diet upregulated the relative m RNA expression of Occludin,ZO-1,γ-GCLc and IL-10 of the jejunum(P<0.05),whereas downregulated the relative m RNA expression of NF-κB p65,TNF-αand IL-1βof the jejunum(P<0.05).Dietary EPS increased the protein expression of Occludin and ZO-1,whereas it reduced the protein expression of NF-κB p65 and MLCK(P<0.01)and tended to decrease the protein expression of TNF-α(P=0.094)in heat-stressed broilers.Furthermore,the proportions of Bacteroides and Oscillospira among the three groups were positively associated with jejunal apoptosis and pro-inflammatory cytokine expression(P<0.05)and negatively correlated with jejunal Occludin level(P<0.05).However,the proportions of Lactobacillus,Barnesiella,Subdoligranulum,Megasphaera,Collinsella,and Blautia among the three groups were positively related to ADG(P<0.05).Conclusions EPS can be used as a feed additive in yellow-feathered broilers.It effectively improves growth performance and alleviates HS-induced intestinal injury by relieving inflammatory damage and improving the tight junction proteins expression.These beneficial effects may be related to inhibiting NF-κB/MLCK signaling pathway activation and regulation of cecal microbiota.

Zinc glycine chelate ameliorates DSS‑induced intestinal barrier dysfunction via attenuating TLR4/NF‑κB pathway in meat ducks

Background Zinc glycine chelate(Zn-Gly)has anti-inflammation and growth-promoting properties;however,the mechanism of Zn-Gly contribution to gut barrier function in Cherry Valley ducks during intestinal inflammation is unknown.Three-hundred 1-day-old ducks were divided into 5 groups(6 replicates and 10 ducks per replicate)in a completely randomized design:the control and dextran sulfate sodium(DSS)groups were fed a corn-soybean meal basal diet,and experimental groups received supplements of 70,120 or 170 mg/kg Zn in form of Zn-Gly.The DSS and treatment groups were given 2 mL of 0.45 g/mL DSS daily during d 15–21,and the control group received normal saline.The experiment lasted 21 d.Results Compared with DSS group,70,120 and 170 mg/kg Zn significantly increased body weight(BW),villus height and the ratio of villus to crypt,and significantly decreased the crypt depth of jejunum at 21 d.The number of goblet cells in jejunal villi in the Zn-Gly group was significantly increased by periodic acid-Schiff staining.Compared with control,the content of intestinal permeability marker D-lactic acid(D-LA)and fluxes of fluorescein isothiocyanate(FITC-D)in plasma of DSS group significantly increased,and 170 mg/kg Zn supplementation significantly decreased the D-LA content and FITC-D fluxes.Compared with control,contents of plasma,jejunum endotoxin and jejunum pro-inflammatory factors IL-1β,IL-6 and TNF-αwere significantly increased in DSS group,and were significantly decreased by 170 mg/kg Zn supplementation.Dietary Zn significantly increased the contents of anti-inflammatory factors IL-10,IL-22 and sIgA and IgG in jejunum.Real-time PCR and Western blot results showed that 170 mg/kg Zn supplementation significantly increased mRNA expression levels of CLDN-1 and expression of OCLN protein in jejunum,and decreased gene and protein expression of CLDN-2 compared with DSS group.The 120 mg/kg Zn significantly promoted the expressions of IL-22 and IgA.Dietary Zn-Gly supplementation significantly decreased pro-inflammatory genes IL-8 and TNF-αexpression levels and TNF-αprotein expression in jejunum.Additionally,Zn significantly reduced the gene and protein expression of TLR4,MYD88 and NF-κB p65.Conclusions Zn-Gly improved duck BW and alleviated intestinal injury by regulating intestinal morphology,barrier function and gut inflammation-related signal pathways TLR4/MYD88/NF-κB p65.

Elaidic acid-induced intestinal barrier damage led to gut-liver axis derangement and triggered NLRP3 inflammasome in the liver of SD rats

Previous studies have shown that trans fatty acids(TFA) are associated with several chronic diseases,the gut microbiota is directly influenced by dietary components and linked to chronic diseases.Our research investigated the effects of elaidic acid(EA),a typical TFA,on the gut microbiota to understand the underlying mechanisms of TFA-related chronic diseases.16S rDNA gene sequencing on faecal samples from Sprague-Dawley rats were performed to explore the composition change of the gut microbiota by EA gavage for 4 weeks.The results showed that the intake of EA increased the abundance of well-documented harmful bacteria,such as Proteobacteria,Anaerotruncus,Oscillibacter and Desulfovibrionaceae.Plus,EA induced translocation of lipopolysaccharides(LPS) and the above pathogenic bacteria,disrupted the intestinal barrier,led to gut-liver axis derangement and TLR4 pathway activation in the liver.Overall,EA induced intestinal barrier damage and regulated TLR4-MyD88-NF-κB/MAPK pathways in the liver of SD rats,leading to the activation of NLRP3 inflammasome and inflammatory liver damage.

The Effect of Immunotherapy on the Gut Microbiota,Intestinal Barrier,and Immune Function in Patients with Gastric Cancer

Objective:To explore the effect of immunotherapy on the gut microbiota,intestinal barrier,and immune function in patients with gastric cancer.Methods:From July 2023 to July 2024,60 patients with gastric cancer from our hospital were randomly divided into two groups,the control group and the study group,with 30 patients in each group.The control group received conventional treatment,while the study group received immunotherapy.A comparative analysis was conducted between the two groups on gut microbiota content(Bifidobacterium,Fusobacterium nucleatum,Streptococcus,Lactobacillus acidophilus),intestinal barrier indicators[D-lactate(D-LA),diamine oxidase(DAO),lipopolysaccharide(LPS)],immune function indicators[Immunoglobulin A(IgA),Immunoglobulin G(IgG),Immunoglobulin M(IgM)],adverse reactions,and treatment effects.Results:After treatment,the content of Bifidobacterium and Fusobacterium nucleatum in the study group was higher than in the control group,while the content of Streptococcus and Lactobacillus acidophilus was lower than in the control group(P<0.05).The levels of D-lactate and DAO in the study group were lower than in the control group,while the LPS level in the study group was higher(P<0.05).The levels of IgA and IgG in the study group were lower than in the control group,and the IgM level was also lower than in the control group(P<0.05).After treatment,the total incidence of adverse reactions in the study group was lower than in the control group(P<0.05).The overall treatment efficacy rate in the study group was higher than in the control group(P<0.05).Conclusion:Immunotherapy in patients with gastric cancer can improve gut microbiota,intestinal barrier,and immune function,reduce the occurrence of adverse reactions,and promote better clinical treatment outcomes,making it worthy of clinical recommendation.

Role of gut microbiota on intestinal barrier function in acute pancreatitis

Acute pancreatitis(AP)is a common gastrointestinal disorder.Approximately15%-20%of patients develop severe AP.Systemic inflammatory response syndrome and multiple organ dysfunction syndrome may be caused by the massive release of inflammatory cytokines in the early stage of severe AP,followed by intestinal dysfunction and pancreatic necrosis in the later stage.A study showed that 59%of AP patients had associated intestinal barrier injury,with increased intestinal mucosal permeability,leading to intestinal bacterial translocation,pancreatic tissue necrosis and infection,and the occurrence of multiple organ dysfunction syndrome.However,the real effect of the gut microbiota and its metabolites on intestinal barrier function in AP remains unclear.This review summarizes the alterations in the intestinal flora and its metabolites during AP development and progression to unveil the mechanism of gut failure in AP.

Effects of dietary supplementation of probiotic,Clostridium butyricum,on growth performance,immune response,intestinal barrier function,and digestive enzyme activity in broiler chickens challenged with Escherichia coli K88

Background： Colibacillosis caused by enterotoxigenic Escherichia coil （E. coil} results in economic losses in the poultry industry. Antibiotics are usually used to control colibacillosis, however, E. coli has varying degrees of resistance to different antibiotics. Therefore the use of probiotics is becoming accepted as an alternative to antibiotics. In this study, we evaluated the effects of Clostfidium butyricum （C. butyficum） on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Eschefichia coli （E. coil） K88. Methods： The chickens were randomly divided into four treatment groups for 28 days. Negative control treatment （NC） consisted of birds fed a basal diet without E. coil K88 challenge and positive control treatment （PC） consisted of birds fed a basal diet and challenged with E. coil K88. C. buO/ricum probiotic treatment （CB） consisted of birds fed a diet containing 2 x 107 cfu C. buO/ricum/kg of diet and challenged with E. coil K88. Colistin sulfate antibiotic treatment （CS） consisted of birds fed a diet containing 20 mg colistin sulfate/kg of diet and challenged with E. coil K88. Results： The body weight （BW） and average day gain （ADG） in the broilers of CB group were higher （P 〈 0.05） than the broilers in the PC group overall except the ADG in the 14-21 d post-challenge. The birds in CB treatment had higher （P 〈 0.05） concentration of tumor necrosis factor-a （TNF-a） at 3 and 7 d post-challenge, and higher （P 〈 0.05） concentration of interleukin-4 （IL-4） at 14 d post-challenge than those in the PC treatment group. The concentration of serum endotoxin in CB birds was lower （P 〈 0.05） at 21 d post-challenge, and the concentrations of serum diamine oxidase in CB birds were lower （P 〈 0.05） at 14 and 21 d post-challenge than in PC birds. Birds in CB treatment group had higher （P 〈 0.05） jejunum villi height than those in PC, NC, or CS treatment at 7, 14, and 21 d post-challenge. In comparison to PC birds, the CB birds had lower （P 〈 0.05） jejunum crypt depth during the whole experiment. The birds in CB or CS treatment group had higher （P 〈 0.05） activities of amylase and protease at 3, 7, and 14 d post-challenge, and higher （P 〈 0.05） activity of lipase at 3, 7 d post-challenge than PC birds.

Gegen Qinlian decoction enhances immunity and protects intestinal barrier function in colorectal cancer patients via gut microbiota

BACKGROUND We previously showed,using the Traditional Chinese Medicine System Pharmacology Database,that Gegen Qinlian decoction(GQD)had a direct antitumor effect,and was combined with programmed cell death protein(PD)-1 inhibitors to treat microsatellite stable(MSS)tumor-bearing mice.However,the effect of GQD on patients with colorectal cancer(CRC)is not clear.AIM To determine the therapeutic mechanism of GQD in improving immune function,reducing inflammation and protecting intestinal barrier function.METHODS Seventy patients with CRC were included in this study:37 in the control group and 33 in the treatment group.The proportions of CD4+T,CD8+T,natural killer(NK),NKT and T regulatory cells were measured by flow cytometry.Levels of the cytokines tumor necrosis factor(TNF)-α,interferon(IFN)-γ,interleukin(IL)-2,IL-6,IL-10 and serotonin(5-hydroxytryptamine;5-HT)in serum were assessed by enzyme-linked immunosorbent assay(ELISA).The expression of zonula occludens(ZO)-1,occludin,nuclear factor(NF)-κB and TNF-αin tumor and normal tissues was measured by immunohistochemistry.The composition of gut microbiota from patients in the treatment group was assessed using 16S rDNA analysis.RESULTS There were no adverse events in the treatment group.The proportion of CD4+T cells and NKT cells in the post-treatment group was significantly higher than that in the pre-treatment and control groups(P<0.05).The level of TNF-αin the posttreatment group was significantly lower than that in the pre-treatment and control groups(P<0.05).The concentration of 5-HT in the post-treatment group was significantly lower than that in the pre-treatment group(P<0.05).The expression of ZO-1 and occludin in tumor tissues in the treatment group was significantly higher than that in the control group(P<0.05).The expression of ZO-1 in normal tissues of the treatment group was significantly higher than that in the control group(P=0.010).Compared with the control group,expression of NF-κB and TNF-αin tumor tissues of the treatment group was significantly decreased(P<0.05).Compared with the pre-treatment group,GQD decreased the relative abundance of Megamonas and Veillonella.In addition,GQD increased the relative abundance of Bacteroides,Akkermansia and Prevotella.CONCLUSION GQD enhances immunity and protects intestinal barrier function in patients with CRC by regulating the composition of gut microbiota.

Glutamine and recombinant human growth hormone protect intestinal barrier function following portal hypertension surgery

AIM： To evaluate the effects of combined treatment of glutamine （Gln） and recombinant human growth hormone（rhGH） on intestinal barrier function following portal hypertension surgery. METHODS： This study was designed as a prospective, randomized and controlled clinical trial. Forty two patients after portal hypertension surgery were randomly assigned into 2 groups： control group （n = 20） and supplemental group （adding Gin and rhGH, n = 22）. Every patient received isocaloric and isonitrogenous standard total parenteral nutrition （TPN） starting 3 d after surgery for 7 d. Blood samples were obtained before surgery and at the 3rd and 10th day postoperatively. Host immunity was evaluated by measuring levels of CD4, CD8, CD4/CD8, IgG, IgM and IgA, and the inflammatory responses were determined by assessing IL-2, TNF-α and C-reactive protein （CRP） levels. Intestinal permeability and integrity was evaluated by L/M test and histological examination, respectively. RESULTS： On postoperative d 10, CD4, CD4/CD8, IgG and IL-2 levels in supplemental group were significantly higher than those in control group （33.7±5.5 vs 31.0 ± 5.4, P 〈 0.05, （1.17±0.32 vs 1.05 ± 0.15, P 〈 0.05, 13.94±1.09 vs 12.33±1.33, P 〈 0.05, and 368.12 ± 59.25 vs 318.12 ± 45.65, P 〈 0.05, respectively）, whereas the increase in serum TNF-α concentration was significantly reduced （41.02 ± 27.56 vs 160.09 ± 35.17, P 〈 0.05）. The increase in L/M ratio was significantly lower in the supplemental group than in the control group （0.0166 ± 0.0017 vs 0.0339 ± 0.0028, P 〈 0.05）. Moreover, mucosal integrity in the supplemental group was better than in the control group.CONCLUSION： Postoperative administration of TPN supplemented with Gin and rhGH in patients after portal hypertension surgery improves immune function, modulates inflammatory response, prevents the intestinal mucous membrane from atrophy and preserves intestinal integrity.

Protective effect of probiotics on intestinal barrier function in malnourished rats after liver transplantation

BACKGROUND: Most patients waiting for liver transplantation have end-stage liver diseases with malnutrition, which is prone to induce intestinal barrier dysfunction after liver transplantation. We aimed to study the effect of probiotics on intestinal barrier function in malnourished rats following liver transplantation with long-term antibiotics. METHODS: Twelve Lewis rats were selected as donors. Twelve BN rats, which served as recipients, were subjected to malnutrition by semi-starvation for 4-5 weeks. They were randomly divided into two groups: a control group which received phosphate-buffered saline and a probiotics group which received Bifidobacterium and Lactobacillus. All recipients were injected with intramuscular imipenem and subcutaneous cyclosporine A. Furthermore, six normal BN rats without any drugs or operations served as a normal group. Eight days after operation, all rats were sacrificed for examination of the following parameters: serum levels of endotoxin and TNF-α, bacterial translocation, intestinal microflora, ileocecal sIgA, lymphocyte numbers, and phenotypes (CD4, CD8, αβTCR, γδTCR)ofPeyer’spatches. RESULTS: In recipients subjected to malnutrition, weight decreased by 20% and they survived until 8 days after operation. Compared with the normal group, all recipients on postoperative day 8 showed increased levels of serum endotoxin and TNF-α as well as increased counts oftranslocated bacteria. Meanwhile, there were decreases in counts of Bifidobacterium and Lactobacillus in the ileocecum, sIgA concentration, and lymphocytes of Peyer’s patches. Moreover, partial alteration in lymphocyte phenotypes was evidenced by elevated ratios of CD8 + and γδTCR + lymphocytes. In contrast, compared to the control group, supplementation with probiotics reduced the levels of serum endotoxin, TNF-α and bacterial translocation, increased the counts of Bifidobacterium and Lactobacillus, the concentration of sIgA and lymphocytes of Peyer’s patches, and also slightly restored the alteration of lymphocyte phenotypes. CONCLUSION: Supplementation with probiotics including Bifidobac-terium and Lactobacillus promoted partial restoration of intestinal microflora and improved intestinal barrier function in malnourished rats after liver transplantation with long-term use of antibiotics.

Enteral supplementation with glycyl-glutamine improves intestinal barrier function after liver transplantation in rats

BACKGROUND:Most patients after liver transplantation (LT) suffer from intestinal barrier dysfunction.Glycyl-glutamine (Gly-Gln) by parenteral supplementation is hydrolyzed to release glutamine,which improves intestinal barrier function in intestinal injury.This study aimed to investigate the effect of GlyGln by enteral supplementation on intestinal barrier function in rats after allogenetic LT under immunosuppressive therapy.METHODS:Twelve inbred Lewis rats were selected randomly as donors,and 24 inbred Brown Norway (BN) rats as recipients of allogenetic LT.The recipients were divided into a control group (Ala,n=12) and an experimental group (Gly-Gln,n=12).In each group,6 normal BN rats were sampled for normal parameters on preoperative day 3.The 6 recipients in the control group received alanine (Ala) daily by gastric perfusion for 3 preoperative days and 7 postoperative days,and the 6 recipients in the experimental group were given Gly-Gln in the same manner.The 12 BN recipients underwent orthotopic LT under sterile conditions after a 3-day fast and were given immunosuppressive therapy for 7 days.They were harvested for sampling on postoperative day 8.The following parameters were assessed:intestinal mucosal protein content,mucosal ultrastructure,ileocecal sIgA content,portal plasma levels of endotoxin and TNF-α,and bacterial translocation.RESULTS:All recipients were alive after LT.On preoperative day 3,all parameters were similar in the two groups.On postoperative day 8,all parameters in the two groups were remarkably changed from those on preoperative day 3.However,compared to the Ala group,supplementation withGly-Gln increased the levels of intestinal mucosal protein and ileocecal sIgA,improved mucosal microvilli,and decreased portal plasma levels of endotoxin and TNF-α as well as bacterial translocation.CONCLUSION:Enteral supplementation with Gly-Gln improved intestinal barrier function after allogenetic LT in rats.

Microencapsulated essential oils combined with organic acids improves immune antioxidant capacity and intestinal barrier function as well as modulates the hindgut microbial community in piglets

Background:The objective of this experiment was to evaluate the effect of a combination of microencapsulated essential oils and organic acids(MOA)on growth performance,immuno-antioxidant status,intestinal barrier function and microbial structure of the hindgut in piglets.A total of 120 piglets(Duroc×[Landrace×Yorkshire];weighted 7.66±1.79 kg,weaned at d 28)were randomly selected and allocated to 3 treatments with 4 replicates per group and 10 piglets per replicate according to the initial body weight and gender.The dietary treatments were as follows:1)basal diet(Ctrl);2)Ctrl+chlortetracycline(75 mg/kg)(AGP);3)Ctrl+MOA(1500 mg/kg).The experiment period was lasted for 21 d.Results:Compared to the Ctrl group,dietary supplemented MOA alleviated(P<0.05)the diarrhea rate from d 12 to 21,enhanced(P<0.05)the concentration of serum interlukin-10 and glutathione peroxidase in piglets on d 11 after weaning and serum superoxide dismutase in 21-day piglets.The MOA group also improved(P<0.05)the apparent digestibility of dry matter(DM),organic matter(OM)and gross energy(GE),up-regulated(P<0.05)the mRNA expression level of occludin,claudin-1 and mucin-2 in ileum and increased(P<0.05)the contents of propionic and butyric acids in the cecum of piglets.The MOA group modulated the cecal and colonic microbial community structure and increased(P<0.05)the abundance of Faecalibacterium and Muribaculaceae in cecum and Streptococcus and Weissella in colon.Additionally,AGP group decreased(P<0.05)apparent digestibility of DM,OM and GE as well as down-regulated(P<0.05)relative gene expression level of claudin-1 in duodenum and jejunum,ZO-1 and mucin-1 in jejunum of piglets.Conclusion:In summary,dietary supplemented MOA alleviated diarrhea and improved nutrient apparent digestibility in piglets via enhancing immuno-antioxidant properties,increasing digestive enzyme activity,upregulating the expression of intestinal barrier-related genes,and modifying the microbial community structure of the cecum and colon.Therefore,dietary supplementation with MOA as an alternative to antibiotics was feasible to improve intestinal health of piglets in practical production.

Relationship between expression of triggering receptor-1 on myeloid cells in intestinal tissue and intestinal barrier dysfunction in severe acute pancreatitis

BACKGROUND：Triggering receptor expressed on myeloid cells-1 （TREM-1） in the intestine was upregulated and correlated with disease activity in inflammatory bowel diseases. Membrane- bound TREM-1 protein is increased in the pancreas, liver and kidneys of patients with severe acute pancreatitis （SAP）, suggesting that TREM-1 may act as an important mediator of inflammation and subsequent extra-pancreatic organ injury. This study aimed to investigate the relationship between the expression of TREM-1 in intestinal tissue and intestinal barrier dysfunction in SAP. METHODS： Sixty-four male Wistar rats were randomly divided into a sham operation group （SO group, n=32） and a SAP group （n=32）. A SAP model was established by retrograde injection of 5% sodium deoxycholate into the bile-pancreatic duct. Specimens were taken from blood and intestinal tissue 2, 6, 12, and 48 hours after operation respectively. The levels of D-lactate, diamine oxidase （DAO） and endotoxin in serum were measured using an improved spectro-photometric method. The expression levels of TREM-1, interleukin-1β （IL-1β）, and tumor necrosis factor-α （TNF-α） mRNA in terminal ileum were detected by real-time reverse transcription-polymerase chain reaction （RT-PCR）. Specimens of the distal ileum were taken to determine pathological changes by a validated histology score. The serum levels of D-lactate, DAO and endotoxin were significantly increased in each subgroup of SAP compared with the SO group （P〈0.01, P〈0.05）. The expression levels of TREM-1, IL-1β and TNF-a mRNA in the terminal ileum in each subgroup of SAP were significantly higher than those in the SO group （P〈0.01, P〈0.05）. The expression level of TREM-lmRNA was positively correlated with IL-1βand TNF-α mRNA （r=0.956, P=0.044; r=0.986, P=0.015）, but the correlation was not found between IL-1β mRNA and TNF-a mRNA （P=0.133）. Compared to the SO group, the pathological changes were aggravated significantly in the SAP group. CONCLUSIONS： The expression level of TREM-1 in intestinal tissue of rats with SAP was elevated, leading to the release of inflammatory mediators and intestinal mucosal injury. This finding indicates that TREM-I might play an important role in the development of intestinal barrier dysfunction in rats with SAP.

Yeast hydrolysate attenuates lipopolysaccharide-induced inflammatory responses and intestinal barrier damage in weaned piglets

Background Intestinal inflammation is the main risk factor causing intestinal barrier dysfunction and lipopolysaccharide(LPS)can trigger inflammatory responses in various eukaryotic species.Yeast hydrolysate(YH)possesses multibiological effects and is received remarkable attention as a functional ingredient for improving growth performance and promoting health in animals.However,there is still inconclusive on the protective effects of dietary YH supplementation on intestinal barrier of piglets.This study was conducted to investigate the attenuate effects of YH supplementation on inflammatory responses and intestinal barrier injury in piglets challenged with LPS.Methods Twenty-four piglets(with an average body weight of 7.42±0.34 kg)weaned at 21 days of age were randomly assigned to one of two dietary treatments(12 replications with one pig per pen):a basal diet or a basal diet containing YH(5 g/kg).On the 22nd d,6 piglets in each treatment were intraperitoneally injected with LPS at 150μg/kg BW,and the others were injected with the same amount of sterile normal saline.Four hours later,blood samples of each piglet were collected and then piglets were euthanized.Results Dietary YH supplementation increased average daily feed intake and average daily gain(P<0.01),decreased the ratio of feed intake to gain of piglets(P sponse,evidenced by the increase o=0.048).Lipopolysaccharide(LPS)injection induced systemic inflammatory ref serum concentrations of haptoglobin(HP),adrenocorticotropic hormone(ACTH),cortisol,and interleukin-1β(IL-1β).Furthermore,LPS challenge resulted in inflammatory intestinal damage,by up-regulation of the protein or mRNA abundances of tumor necrosis factor-α(TNF-α),IL-1β,toll-like receptors 4(TLR4)and phosphor-nuclear factor-κB-p65(p-NFκB-p65)(P<0.01),and down-regulation of the jejunal villus height,the protein and mRNA abundances of zonula occludens-1(ZO-1)and occludin(OCC;P<0.05)in jejunal mucosa.Dietary YH supplementation decreased the impaired effects of ACTH,cortisol,HP,IL-1βand diamine oxidase in serum(P<0.05).Moreover,YH supplementation also up-regulated the jejunal villus height,protein and mRNA abundances of ZO-1 and OCC(P<0.05),down-regulated the mRNA expressions of TNF-αand IL-1βand the protein abundances of TNF-α,IL-1β,TLR4 and p-NFκB-p65 in jejunal mucosa in LPS-challenged pigs(P<0.01).Conclusion Yeast hydrolysate could attenuate inflammatory response and intestinal barrier injury in weaned piglets challenged with LPS,which was associated with the inhibition of TLR4/NF-κB signaling pathway activation.

Intestinal barrier in inflammatory bowel disease

A complex mucosal barrier protects as the first line of defense the surface of the healthy intestinal tract from adhesion and invasion by luminal microorganisms. In this review, we provide an overview about the major components of this protective system as for example an intact epithelium, the synthesis of various antimicrobial peptides (AMPs) and the formation of the mucus layer. We highlight the crucial importance of their correct functioning for the maintenance of a proper intestinal function and the prevention of dysbiosis and disease. Barrier disturbances including a defective production of AMPs, alterations in thickness or composition of the intestinal mucus layer, alterations of pattern-recognition receptors, defects in the process of autophagy as well as unresolved endoplasmic reticulum stress result in an inadequate host protection and are thought to play a crucial role in the pathogenesis of the inflammatory bowel diseases Crohn&#x02019;s disease and ulcerative colitis.

MicroRNAs:New therapeutic targets for intestinal barrier dysfunction

Defects in intestinal barrier function characterized by an increase in intestinal permeability contribute to intestinal inflammation.Growing evidence has shown that an increase in intestinal permeability has a pathogenic role in diseases such as inflammatory bowel disease(IBD)and celiac disease,and functional bowel disorders such as irritable bowel syndrome.Therefore,clarification of the inflammatory responses,the defense pathway and the corresponding regulatory system is essential and may lead to the development of new therapies.MicroRNAs(miRNAs)are small(19-22nt)noncoding RNA molecules that regulate genes at the post-transcriptional level by base-pairing to specific messenger RNAs for degradation to repress translation.Recent studies suggested that miRNAs are important in the immune response and mediate a critical role in multiple immune response-related disorders.Based on these discoveries,attention has been focused on understanding the role of miRNAs in regulating intestinal barrier dysfunction,especially in IBD.Here,we provide a review of the most recent state-of-the-art research on miRNAs in intestinal barrier dysfunction.

Tauroursodeoxycholic acid(TUDCA)improves intestinal barrier function associated with TGR5-MLCK pathway and the alteration of serum metabolites and gut bacteria in weaned piglets

Background:Tauroursodeoxycholic acid(TUDCA),a hydrophilic bile acid,is the main medicinal component of bear bile and is commonly used to treat a variety of hepatobiliary diseases.Meanwhile,TUDCA has been shown to modulate the intestinal barrier function and alleviate DSS-induced colitis in mice.However,the effect of TUDCA on the intestinal barrier of weaned piglets remains largely unclear.Methods:The weaned piglets and porcine IPEC-J2 intestinal epithelial cells were used to investigate the effects of TUDCA on intestinal barrier function in weaned piglets and explore the possible underlying mechanisms.In vivo,72 healthy weaned piglets were randomly allocated into 2 groups according to their gender and body weight,and piglets were fed the basal diet with 0(control,CON)and 200 mg/kg TUDCA for 30 d,respectively.Three female and three male piglets reflecting the average bodyweight were slaughtered in each group and samples were collected.In vitro,IPEC-J2 cells were subjected to 100μmol/L TUDCA to explore the possible underlying mechanisms.Results:Our results demonstrated that dietary TUDCA supplementation significantly reduced the diarrhea incidence of weaned piglets,possibly attributing to the TUDCA-enhanced intestinal barrier function and immunity.In addition,TUDCA supplementation altered serum metabolites and the relative abundance of certain gut bacteria,which might contribute to the improved intestinal barrier function.Furthermore,the in-vitro results showed that TUDCA improved the E.coli-induced epithelial barrier impairment of IPEC-J2 cells and increased Takeda G-coupled protein receptor 5(TGR5)protein expression.However,knockdown of TGR5 and inhibition of myosin light chain kinase(MLCK)pathway abolished the TUDCA-improved epithelial barrier impairment in E.coli-treated IPEC-J2 cells,indicating the involvement of TGR5-MLCK in this process.Conclusions:These findings showed that TUDCA improved intestinal barrier function associated with TGR5-MLCK pathway and the alteration of serum metabolites and gut bacteria in weaned piglets,suggesting the potential application of TUDCA in improving gut health in piglet production.

The synbiotic mixture of lactulose and Bacillus coagulans protects intestinal barrier dysfunction and apoptosis in weaned piglets challenged with lipopolysaccharide

Background Lactulose as an effective prebiotic protects intestinal mucosal injury.Bacillus coagulans is widely used in feed additives because of its ability to promote intestinal health.Our previous study suggests that the combination of lactulose and Bacillus coagulans may be a good candidate as alternative for antibiotic growth promoters.However,the in vivo effects of lactulose and Bacillus coagulans on growth and intestinal health under immune challenge in piglets remains unclear.The objective of this study is to explore the protective effects of synbiotic containing lactu-lose and Bacillus coagulans on the intestinal mucosal injury and barrier dysfunction under immune challenge in weaned piglets.Methods Twenty four weaned piglets were assigned to 4 groups.Piglets in the CON-_(saline)and LPS-_(LPS)group were fed the basal diet,while others were fed either with chlortetracycline(CTC)or synbiotic mixture of lactulose and Bacillus coagulans for 32 d before injection of saline or lipopolysaccharide(LPS).Piglets were sacrificed 4 h after LPS injection to collect samples to determine intestinal morphology,integrity and barrier functions as well as relative genes and proteins.Results Our data showed that no differences were observed in the growth performance of the four test groups.LPS injection induced higher serum diamine oxidase activities,D-lactic acid levels,and endotoxin status,lower villus height and ratio of villus height to crypt depth,greater mRNA and lower protein expression related tight junction in both jejunum and ileum.In addition,a higher apoptosis index,and protein expression of Bax and caspase-3 were also observed in the LPS challenge group.Interestingly,dietary synbiotic mixture with lactulose and Bacillus coagulans protected against LPS-induced intestinal damage,barrier dysfunction and higher apoptosis as well as CTC.Conclusions Our data suggest that dietary supplementation of synbiotic mixture with lactulose and Bacillus coagu-lans showed resilience to LPS-induced intestinal morphological damage,barrier dysfunction and aggressive apoptosis in piglets as well as the protective effects of CTC.These results indicate that synbiotic mixture of lactulose and Bacillus coagulans showed beneficial effects on performance and resilience to acute immune stress in weaned piglets.

Effect of EPEC endotoxin and bifidobacteria on intestinal barrier function through modulation of toll-like receptor 2 and toll-like receptor 4 expression in intestinal epithelial cell-18

AIM To investigate toll-like receptor 2(TLR2) and TLR4 expression, following bifidobacteria and low-dose EPEC endotoxin treatment, and intestinal barrier function in rat intestinal epithelial cell-18(IEC-18).METHODS Six experimental groups were established-normal control, EPEC, Bifidobacteria infantis(B. infantis), B. longum, B. bifidum, and B. youth groups. Optimal EPEC endotoxin concentration, bifidobacteria fold dilution, and treatment duration were determined. Quantitative real-time polymerase chain reaction and western blot, respectively, were conducted to detect TLR2 and TLR4 m RNA and protein expression in IEC-18 cells. Transepithelial electrical resistance(TEER) was measured by the EVOM chopstick voltohmmeter in each group. All experiments were conducted in triplicate and data were analyzed on SPSS 16.RESULTS TLR2 and TLR4 m RNA and protein expression in the EPEC group were significantly higher than in the control group(P < 0.05). TLR2 m RNA and protein expression in the B. infantis, B. longum and B. youth groups were significantly lower than in the normal control group(P < 0.05). TLR4 m RNA and protein expression in the B. bifidum and B. youth groups were significantly lower than in normal controls(P < 0.05). In addition, the TEER in B. infantis, B. longum, B. bifidum, and B. youth groups were decreased by 19%, 18%, 23% and 23%, respectively, after 120 min of intervention, as compared to the control group. However, the TEER in the EPEC group was significantly decreased by 67% in comparison to the normal control group(P < 0.05).CONCLUSION Bifidobacteria protect IEC-18 cells against injury by down-regulating TLR2 and TLR4 expression and enhance intestinal barrier function to protect the intestinal epithelial cells from pathogenic invasion.