Bacterial lipopolysaccharide with different administration routes affects intestinal mucosal morphological, immunological, and microbial barrier functions in goslings

The current study was conducted to evaluate the effects of different administration routes of bacterial lipopolysaccharide (LPS) on intestinal mucosal morphological, immunological, and microbial barrier functions in goslings. First, we compared intestinal villi morphology of goslings under intraperitoneal or oral LPS treatment through hematoxylin and eosin staining. Then, we determined the signatures of the microbiome in the ileum mucosa of goslings subjected to oral LPS treatment at 0, 2, 4, and 8 mg/kg BW by 16S sequencing, and analyzed the changes in intestinal barrier functions and permeability, levels of LPS in the ileum mucosa, plasma, and liver tissue, and the induced inflammatory response of Toll-like receptor 4 (TLR4). As a result, intraperitoneal LPS injection resulted in a thicker intestinal wall in the ileum within a short time, whereas villus height was less affected; in contrast, oral LPS treatment exerted a stronger influence on villus height but not on intestinal wall thickness. We also found that oral LPS treatment affected the structure of the intestinal microbiome, reflected by changes in the clustering of intestinal microbiota. The average abundance of Muribaculaceae showed an increasing trend with increasing LPS levels, and that of the genus Bacteroides decreased, compared with the control group. In addition, oral LPS treatment with 8 mg/kg BW affected the intestinal epithelial morphology, damage the mucosal immune barrier, downregulated the expression of tight junction proteins, increased circulating D-lactate levels, and stimulated the secretion of various inflammatory mediators and activation of the TLR4/MyD88/NFκB pathway. This study presented the injuries of intestinal mucosal barrier function induced by LPS challenges in goslings and provided a scientific model for searching the novel strategies to attenuate the immunological stress and gut injury caused by LPS.

Gut-derived low-grade endotoxaemia, atherothrombosis and cardiovascular disease

Systemic inflammation has been suggested to have a pivotal role in atherothrombosis, but the factors that trigger systemic inflammation have not been fully elucidated. Lipopolysaccharide (LPS) is a component of the membrane of Gram-negative bacteria present in the gut that can translocate into the systemic circulation, causing non-septic, low-grade endotoxaemia. Gut dysbiosis is a major determinant of low-grade endotoxaemia via dysfunction of the intestinal barrier scaffold, which is a prerequisite for LPS translocation into the systemic circulation. Experimental studies have demonstrated that LPS is present in atherosclerotic arteries but not in normal arteries. In atherosclerotic plaques, LPS promotes a pro-inflammatory status that can lead to plaque instability and thrombus formation. Low-grade endotoxaemia affects several cell types, including leukocytes, platelets and endothelial cells, leading to inflammation and clot formation. Low-grade endotoxaemia has been described in patients at risk of or with overt cardiovascular disease, in whom low-grade endotoxaemia was associated with atherosclerotic burden and its clinical sequelae. In this Review, we describe the mechanisms favouring the development of low-grade endotoxaemia, focusing on gut dysbiosis and changes in gut permeability; the plausible biological mechanisms linking low-grade endotoxaemia and atherothrombosis; the clinical studies suggesting that low-grade endotoxaemia is a risk factor for cardiovascular events; and the potential therapeutic tools to improve gut permeability and eventually eliminate low-grade endotoxaemia.

Paeoniflorin alleviates inflammatory response in IBS-D mouse model via downregulation of the NLRP3 inflammasome pathway with involvement of miR-29a

Paeoniflorin has been traditionally used to treat pain and immunologic derangement in China. However, its detailed mechanism remains to be illuminated. We investigated the mechanism by which paeoniflorin alleviates the inflammatory response in a mouse model of irritable bowel syndrome with predominant diarrhea (IBS-D). C57BL/6 wild type (WT) and miR-29a knockout (KO) mice were randomly divided into control, model, rifaximin, and paeoniflorin groups (n = 7). IBS-D model was induced by single intracolonic instillation of 0.1 mL trinitro-benzene-sulfonic acid (TNBS, 50 mg/mL) combined with restraint stress for seven consecutive days. The treatment groups received rifaximin (100 mg/kg) and paeoniflorin (50 mg/kg) via intragastric administration for seven days, respectively. The results showed that the fecal water content, fecal pellet output, visceral sensitivity, and histopathological score after paeoniflorin treatment were lower than those of the model group in both WT and miR-29a KO mice (P < 0.05). In both lineage mice, damage was observed in the colon tissues of model group, while paeoniflorin treatment partially ameliorated the tissue damage. Serum levels of DAO, DLA, IL-1β, IL-18, TNF-α, and MPO were decreased after paeoniflorin treatment (P < 0.05), with miR-29a KO mice in a lower level compared with that of WT mice. RT-PCR showed that the relative expression of miR-29a, NF-κB (p65), NLRP3, ASC, caspase-1, IL-1β, and TNF-α was downregulated while NKRF was upregulated after paeoniflorin treatment (P < 0.05). Immunohistochemistry showed that intestinal epithelial protein levels of NLRP3, ASC, and caspase-1 decreased while those of Claudin-1 and ZO-1 increased in the paeoniflorin treatment group (P < 0.05). In general, compared with WT mice, NLRP3 inflammasome pathway targets was in much lower expression level than miR-29a KO mice. In conclusion, paeoniflorin could inhibit abnormal activation of the NLRP3 inflammasome pathway by inhibiting miR-29a in IBS-D, thereby relieving the inflammatory response of the intestinal mucosa and reconstructing the intestinal epithelial barrier.

Association of Lipopolysaccharide-Toll-Like Receptor 4 Signaling and Microalbuminuria in Patients with Type 2 Diabetes Mellitus

Purpose

Intestinal flora imbalance has been implicated in the activation of innate immunity in the kidneys. However, little is known about the potential links between lipopolysaccharide (LPS)-toll-like. receptor 4 (TLR4) signaling activated by intestinal barrier dysfunction and microalbuminuria in type 2 diabetes mellitus (T2DM).

Patients and Methods

61 patients with T2DM were stratified based on the absence (n=32) or presence (n=29) of microalbuminuria. There were also 28 control subjects. Urinary albumin excretion rate (UAER), serum levels of LPS, D-lactic acid (DLA), diamine oxidase (DAO), fasting blood glucose (FBG), interleukin-6 (IL-6), glycosylated hemoglobin A1 (HbA1c), and high-sensitivity C-reactive protein (hs-CRP), and TLR4 expression in peripheral blood mononuclear cells (PBMCs) were measured.

Results

hs-CRP, IL-6, LPS, DLA, DAO, and TLR4 were markedly increased in subjects with T2DM compared to the controls (P < 0.05 for all). Moreover, LPS was positively correlated with FBG, HbA1c, hs-CRP, IL-6, UAER, DLA, DAO, and TLR4 (P < 0.05 for all). In addition, TLR4 was positively correlated with UAER, hs-CRP, FBG, DLA, HbA1c, and LPS (P < 0.05 for all). In regression analyses, TLR4, LPS, HbA1c, and hs-CRP were independently associated with UAER (P < 0.05 for all), while FBG, LPS, TLR4, and hs-CRP (P < 0.05 for all) were found to be risk factors for microalbuminuria in T2DM.

Conclusion

Intestinal integrity is compromised in subjects with T2DM, and the activation of LPS-TLR4 signaling might play an important role in the development of microalbuminuria in T2DM.

An evaluation of the protective effects of chlorogenic acid on broiler chickens in a dextran sodium sulfate model: a preliminary investigation

This study was conducted to investigate the protective effects of chlorogenic acid (CGA) on broilers subjected to dextran sodium sulfate (DSS)-induced intestinal damage. One hundred and forty-four 1-day-old male Arbor Acres broiler chicks were allocated into one of 3 groups with 6 replicates of eight birds each for a 21-d trial. The treatments included: 1) Control group: normal birds fed a basal diet; 2) DSS group: DSS-treated birds fed a basal diet; and 3) CGA group: DSS-treated birds fed a CGA-supplemented control diet. An oral DSS administration via drinking water was performed from 15 to 21 d of age. Compared with the control group, DSS administration reduced 21-d body weight and weight gain from 15 to 21 d, but increased absolute weight of jejunum and absolute and relative weight of ileum (P < 0.05). DSS administration elevated circulating D-lactate concentration and diamine oxidase activity (P < 0.05), which were partially reversed when supplementing CGA (P < 0.05). The oral administration with DSS decreased villus height and villus height/crypt depth ratio, but increased crypt depth in jejunum and ileum (P < 0.05). Compared with the control group, DSS administration increased serum glutathione level and jejunal catalase activity and malonaldehyde accumulation, but decreased jejunal glutathione level (P < 0.05). In contrast, feeding a CGA-supplemented diet normalized serum glutathione and jejunal malonaldehyde levels, and increased jejunal glutathione concentration in DSS-administrated birds (P < 0.05). Additionally, CGA supplementation reduced ileal malonaldehyde accumulation in DSS-treated birds (P < 0.05). DSS challenge increased levels of serum interferon-γ and interleukin-6, jejunal interleukin-1β, tumor necrosis factor-α, and interleukin-6, and ileal interleukin-1β and interleukin-6 when compared with the control group (P < 0.05). The elevated serum interferon-γ and ileal interleukin-6 levels were normalized to control values when supplementing CGA (P < 0.05). The results suggested that CGA administration could partially prevent DSS-induced increased intestinal permeability, oxidative damage, and inflammation in broilers, although it did not improve their growth performance and intestinal morphology.

Escherichia coli O88 induces intestinal damage and inflammatory response through the oxidative phosphorylation and ribosome pathway in Pekin ducks

Colibacillosis is one of the major health threats in the poultry industry worldwide. Understanding the pathogenic mechanisms involved in Escherichia coli-induced inflammatory response may lead to the development of new therapies to combat the disease. To address this, a total of 96 1-day-old male lean Pekin ducklings were employed and randomly allocated to two treatments, each with six replicates of eight ducks. Ducks in the experiment group (EG) and the control group (CG) were separately orally administered with 0.2 ml of pathogenic E. coli O88 (3 × 109 CFU/ml) or equivalent volumes of 0.9% sterile saline solution on day 7, two times with an 8-h interval. Serum and intestinal samples were collected on days 9, 14, and 28. Results showed that ducks challenged with E. coli had lower average daily gain and higher feed intake/weight gain during days 9–14 and overall (P &lt; 0.05). Histopathological examination showed that E. coli decreased the villus height and the ratio of villus height/crypt depth in the jejunum (P &lt; 0.05) on days 9 and 14. The intestinal barrier was disrupted, presenting in E. coli ducks having higher serum DAO and D-LA on days 9 and 14 (P &lt; 0.05) and greater content of serum LPS on day 9 (P &lt; 0.05). Escherichia coli infection also triggered a systemic inflammatory response including the decrease of the serum IgA, IgM, and jejunal sIgA on day 14 (P &lt; 0.05). In addition to these, 1,062 differentially expressed genes were detected in the jejunum tissues of ducks by RNA-seq, consisting of 491 upregulated and 571 downregulated genes. Based on the KEGG database, oxidative phosphorylation and the ribosome pathway were the most enriched. These findings reveal the candidate pathways and genes that may be involved in E. coli infection, allow a better understanding of the molecular mechanisms of inflammation progression and may facilitate the genetic improvement of ducks, and provide further insights to tackle the drug sensitivity and animal welfare issues.

Enzymatic hydrolysate of porphyra enhances the intestinal mucosal functions in obese mice

Intestinal mucosal immunity is important to human body; however, obesity induced by high-fat diet may bring a series of problems, such as chronic inflammation which may damage intestinal mucosal immunity. In this study, the effects of two different enzymatic hydrolysates of porphyra on the function of intestinal mucosal were explored in obese mice. The results showed that 10 consecutive weeks of high-fat dietary intake resulted in weight gain and intestinal abnormalities in C57BL/6 mice. However, the administration of enzymatic hydrolysate of porphyra effectively protected the intestinal mucosa from these injuries while reducing levels of oxidative stress (MDA, GSH, and GSH-Px). Specifically, they were found to improve small intestine morphological structure, increase growth of goblet cells and mucous, raise expression levels of lysozyme, and stimulate SIgA secretion, especially in the group administered with the enzymatic hydrolysate containing protease and polysaccharide enzyme (EHPP). The results showed that the enzymatic hydrolysates of porphyra may provide a protective measure to maintain intestinal mucosal barriers, which is beneficial to overall health. Porphyra is widely distributed all over the world. Moreover, an increasing number of studies have described its diverse biological functions. Therefore, it is necessary to find a way to develop products related to porphyra. In this study, a new type of polysaccharide enzyme of porphyra found in our previous research was used to make a clear porphyra energy drink with a lower molecular weight polysaccharide. Our findings highlighted the repaired intestinal barriers in obese bodies after the treatment with the enzymatic hydrolysate. PRACTICAL APPLICATIONS: Porphyra is widely distributed all over the world. Moreover, an increasing number of studies have described its diverse biological functions. Therefore, it is necessary to find a way to develop products related to porphyra. In this study, a new type of polysaccharide enzyme of porphyra found in our previous research was used to make a clear porphyra energy drink with a lower molecular weight polysaccharide. Our findings highlighted the repaired intestinal barriers in obese bodies after the treatment with the enzymatic hydrolysate.

Effect of Dietary Paeoniae Radix Alba Extract on the Growth Performance, Nutrient Digestibility and Metabolism, Serum Biochemistry, and Small Intestine Histomorphology of Raccoon Dog During the Growing Period

Paeoniae radix alba extract (PRA extract) has the functions of regulating immunity, resisting inflammation, and has antioxidant properties. However, current recommendations of dietary PRA extract levels for raccoon dogs were inadequate. The purpose of this experimental study was to gain information allowing for better estimating the effects of PRA extract on raccoon dogs, and their PRA requirements. Fifty healthy male raccoon dogs of (120 ± 5) days old were randomly divided into 5 groups (group PRA0, PRA1, PRA2, PRA4, PRA8) with 10 animals in each group and 1 in each replicate. Five kinds of experimental diets were prepared with five levels of Paeoniae radix alba extract (0, 1, 2, 4, 8 g/kg) in the basic diet. The prefeeding period was 7 days and the experimental period was 40 days. The results showed that the average daily feed intake in group PRA1 and PRA2 was significantly higher than that in other groups (P < 0.01). The dry matter excretion in group PRA8 was significantly higher than that in other groups (P < 0.01), while the dry matter digestibility and protein digestibility in group PRA8 were significantly lower than those in other groups (P < 0.01). Nitrogen retention in group PRA1 and PRA2 was significantly higher than that in group PRA8 (P < 0.05). With the increase of the content of Paeoniae radix alba extract in diet, the activity of alkaline phosphatase in group PRA2 was significantly higher than that in group PRA0 (P < 0.05); The activity of serum SOD in group PRA4 was significantly higher than that in other groups (P < 0.01). The content of serum IgA in group PRA2 was significantly higher than that in other groups (P < 0.05). The content of TNF-α in intestinal mucosa in group PRA1 and group PRA2 was significantly lower than that in group PRA0 (P < 0.05). In conclusion, we found that dietary Paeoniae radix alba extract intake significantly improved the feed intake and nitrogen deposition of Ussuri raccoon dog, increased the content of serum IgA and reduced the content of TNF-α in the small intestinal mucosa. We suggest that an estimated dietary Paeoniae radix alba extract level of 1 to 2 g/kg could be used as a guide to achieve the optimal performance of raccoon dogs.

Caffeine citrate effects on gastrointestinal permeability, bacterial translocation and biochemical parameters in newborn rats after long-term oral administration

BACKGROUND: Caffeine is a potent central and respiratory acting agent used in neonatology to treat apnea in premature newborns. OBJECTIVE: This study investigates the effects of caffeine orally administered to newborn rats on gastrointestinal permeability, bacterial translocation and different biochemical parameters. METHODS: Newborn rats were divided into different groups (N = 06). The treated newborn rats were orally administered with standard caffeine doses (12 mg/kg per day), and the control groups received a placebo. The animals were weighed daily until sacrifice. Blood samples, mesenteric lymph nodes (MLN) and organs were aseptically collected. Furthermore, different biochemical (D-Lactate) and oxidative stress biomarkers (MDA, CAT, SOD and GSH) levels were examined. Microbiological analyses were performed to assess microbiota alterations and bacterial translocation. RESULTS: Preliminary results showed that caffeine administration decreased the level of bacterial translocation over time. The treatment reduced plasma D-lactate levels (p <  0.05). Additionally, caffeine induced a disturbance in the concentrations of biochemical parameters and oxidative stress biomarkers. Indeed, liver enzymes (AST and ALT) were significantly (p <  0.05) risen after caffeine treatment. Glutathione (GSH) levels were significantly higher in caffeine treated groups (75.12±0.32; 51.98±1.12 U/mg; p <  0.05) comparing to control ones (40.82±0.25; 42.91±0.27 U/mg; p <  0.05) in the ileum and the colon, respectively. CONCLUSIONS: Thus, besides improving gastrointestinal permeability, our data show that caffeine has beneficial effects on the intestinal antioxidant system.

Protective Effect of Lactobacillus plantarum P8 on Growth Performance, Intestinal Health, and Microbiota in Eimeria-Infected Broilers

Coccidiosis is one of the major parasitic diseases in the commercial broiler industry. Probiotics can protect poultry against Eimeria infection. However, the mechanisms are not fully known. Therefore, Lactobacillus plantarum P8 (P8) was used to investigate its anti-coccidial property and mechanism. Five hundred broilers were allocated to five treatments: control diet (NC), control diet + Eimeria infection (IC), control diet containing 1 × 10⁷ cfu/g P8 + Eimeria infection (P8L), control diet containing 1 × 10⁸ cfu/g P8 + Eimeria infection (P8H), and control diet + Eimeria infection + Diclazuril (DIC). At day 14, all treatments except NC were inoculated with sporulated oocysts. Results indicated that Eimeria infection increased the mortality and oocysts shedding, and declined the growth performance as well as the intestinal barrier in Eimeria-treated broilers. On the contrary, dietary supplementation of low level P8, high level P8 and DIC decreased the mortality and oocysts shedding, but improved the growth performance and intestinal barrier. The impaired intestinal morphology in the IC group was also improved by P8H and DIC treatments. Besides, the elevated oxidative stress and pro-inflammation in Eimeria-infected broilers were reduced by P8L, P8H, and DIC treatments. Metagenomic analysis indicated P8 altered the structure of the gut microbiota, and the alteration was more obvious at day 21 than day 42. Notably, IC also increased the abundances of Eimeriidae, Eimeria and Eimeria tenella at day 21, while P8L and DIC decreased the abundances. Correlation analysis revealed that bacteria in Eimeria-treated broilers positively correlated with the intestinal permeability, oxidative stress and inflammation, while bacteria in broilers receiving P8L and DIC negatively correlated with the aforementioned pathological indices. Functional prediction demonstrated that the metagenomes of Eimeria-infected broilers were involved in several diseases. But the metagenomes of P8L-treated broilers were involved in energy metabolism and replication repair. In conclusion, dietary P8 supplementation inhibited oocyst shedding and improved the growth performance as well as the intestinal health of broilers infected with Eimeria, which was closely related to the regulation of gut microbiota. Moreover, the effects of P8 may be more effective in the early infection of coccidia.

An altered gut microbiota in duck-origin parvovirus infection on cherry valley ducklings is associated with mucosal barrier dysfunction

Duck-origin parvovirus disease is an epidemic disease mainly caused by duck-origin goose parvovirus (D-GPV), which is characterized by beak atrophy and dwarfism syndrome. Its main symptoms are persistent diarrhea, skeletal dysplasia, and growth retardation. However, the pathogenesis of Cherry Valley ducks infected by D-GPV has not been studied thoroughly. To perceive the distribution of D-GPV in the intestinal tract, intestinal morphological development, intestinal permeability, inflammatory cytokines in Cherry Valley ducks, and expression of tight junction protein, the D-GPV infection was given intramuscularly. Illumina MiSeq sequencing technology was used to analyze the diversity and structure of ileum flora and content of short-chain fatty acids of its metabolites. To investigate the relationship between intestinal flora changes and intestinal barrier function after D-GPV infection on Cherry Valley ducks is of great theoretical and practical significance for further understanding the pathogenesis of D-GPV and the structure of intestinal flora in ducks. The results showed that D-GPV infection was accompanied by intestinal inflammation and barrier dysfunction. At this time, the decrease of a large number of beneficial bacteria and the content of short-chain fatty acids in intestinal flora led to the weakening of colonization resistance of the intestinal flora and the accumulation of potentially pathogenic bacteria, which would aggravate the negative effect of D-GPV damage to the intestinal tract. Furthermore, a significant increase in Unclassified_S24-7 and decrease in Streptococcus was observed in D-GPV persistent, indicating the disruption in the structure of gut microbiota. Notably, the shift of microbiota was associated with the transcription of tight-junction protein and immune-associated cytokines. These results indicate that altered ileum microbiota, intestinal barrier, and immune dysfunction are associated with D-GPV infection. Therefore, there is a relationship between the intestinal barrier dysfunction and dysbiosis caused by D-GPV, but the specific mechanism needs to be further explored.

Necroptosis is active and contributes to intestinal injury in a piglet model with lipopolysaccharide challenge

Necroptosis, a newly discovered form of programmed cell death that combines the features of apoptosis and necrosis, is important in various physiological and pathological disorders. However, the role of necroptosis on intestinal injury during sepsis has been rarely evaluated. This study aimed to investigate the presence of necroptosis in intestinal injury, and its contribution to intestinal injury in a piglet model challenged with Escherichia coli lipopolysaccharide (LPS). Firstly, a typical cell necrotic phenomenon was observed in jejunum of LPS-challenged pigs by transmission electron microscope. Protein expression of necroptosis signals including receptor-interacting protein kinase (RIP) 1, RIP3, and phosphorylated mixed-lineage kinase domain-like protein (MLKL), mitochondrial proteins including phosphoglycerate mutase family member 5 (PGAM5) and dynamin-related protein 1 (DRP1), and cytoplasmic high-mobility group box 1 (HMGB1) were time-independently increased in jejunum of LPS-challenged piglets, which was accompanied by the impairment of jejunal morphology, and digestive and barrier function indicated by lower activities of jejunal disaccharidases and protein expression of jejunal tight junction proteins claudin-1 and occludin. Pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were also dynamically induced in serum and jejunum of piglets after LPS challenge. Moreover, pretreatment with necrostatin-1 (Nec-1), an specific inhibitor of necroptosis, inhibited necroptosis indicated by decreased necrotic ultrastructural changes and decreased protein expression of RIP1, RIP3, and phosphorylated MLKL as well as PGAM5, DRP1, and cytoplasmic HMGB1. Nec-1 pretreatment reduced jejunal morphological injury, and improved digestive and barrier function. Nec-1 pretreatment also decreased the levels of serum and jejunal pro-inflammatory cytokines and the numbers of jejunal macrophages and monocytes. These findings indicate for the first time that necroptosis is present and contributes to LPS-induced intestinal injury. Nec-1 may have a preventive effect on intestinal injury during sepsis.

Adjunctive treatment with probiotics partially alleviates symptoms and reduces inflammation in patients with irritable bowel syndrome

PURPOSE

Irritable bowel syndrome (IBS) is a functional bowel disorder. This study aimed to assess the effect of a probiotic product (containing Lactobacillus casei Zhang, Lactobacillus plantarum P-8, and Bifdobacterium animalis subsp. lactis V9) as an adjunct to a routine regimen in IBS management.

METHODS

Forty-five patients with IBS were randomized into the probiotic (n = 24) and control (n = 21) groups, receiving the routine regimen with or without probiotics for 28 days, respectively. Serum and fecal samples were collected and analyzed.

RESULTS

The IBS-symptom severity score (P < 0.01), serum levels of IL-6 (P < 0.01) and TNF-α (P < 0.001) were significantly lower in the probiotic group than the control group at day 28. The probiotic adjunctive treatment resulted in significant decreases in some bacterial genera that worsen IBS, such as Bacteroides (P < 0.01), Escherichia (P < 0.05), and Citrobacter (P < 0.05), significant decreases were also observed in some beneficial genera in the control group, including Bifidobacterium (P < 0.05), Eubacterium (P < 0.05), Dorea (P < 0.01), and Butyricicoccus (P < 0.05). Furthermore, significant correlations were found between some monitored parameters and compositional changes in the fecal microbiota, suggesting that the clinical improvement of IBS was likely associated with gut microbiota modulation. The enterotype analysis revealed that the initial fecal microbiota composition could influence clinical outcomes.

CONCLUSIONS

The adjunctive use of probiotics with a routine regimen showed additional clinical effectiveness compared to the routine regimen alone in managing IBS. A pretreatment gut microbiome analysis might help tailor a personalized probiotic regimen to optimize treatment effects.

Noninvasive Biomarkers of Gut Barrier Function in Patients Suffering from Diarrhea Predominant-IBS: An Update

The intestinal barrier plays a crucial role in the absorption of nutrients and in preventing the entry of pathogenic microorganisms and toxic molecules. Several studies have shown a compromised intestinal barrier associated with low-grade inflammation in the small intestinal mucosa in celiac disease, inflammatory bowel disease, and irritable bowel syndrome (IBS), particularly in IBS with diarrhea (IBS-D). In light of these new data, IBS is no longer considered a functional disease but rather a heterogeneous syndrome that has yet to be carefully studied. Therefore, investigating the integrity and function of the intestinal barrier is now essential to improving knowledge of the pathophysiology of IBS-D and to improving the management of IBS-D patients. However, the study of the intestinal barrier must clarify some still unsolved methodological aspects and propose standardised assays before becoming a useful diagnostic tool. In this framework, this review will discuss data about the tests that noninvasively evaluate the integrity and functionality of the human intestinal barrier, paying particular attention to patients with IBS-D, in both clinical and research situations.

Lactobacillus johnsonii BS15 improves intestinal environment against fluoride-induced memory impairment in mice-a study based on the gut-brain axis hypothesis

Background

Excessive fluoride can lead to chronic neurodegeneration characterized by neuron and myelin loss and memory dysfunction. The gut–brain axis hypothesis suggests that gut microbiota plays a crucial role in regulating brain function. Thus, using probiotics to adjust the gut microenvironment may be a potential therapy for mental diseases.

Methods

Mice in the prob group were administrated with Lactobacillus johnsonii BS15 for 28 days prior to and throughout a 70-day exposure to sodium fluoride. The drinking water of all groups (F and prob groups) except the control group were replaced by high-fluoride water (100 mg NaF/L) on day 28. Animals in each group were divided into two subsets: one underwent behavioral test, and the other was sacrificed for sampling. The mRNA expression level and protein content related to inflammatory reaction in the ileum and hippocampus were respectively detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of proteins related to myelin structure, apoptosis, and memory in the hippocampus and tight junction proteins in the ileum were determined by RT-qPCR and/or immunohistochemistry. Gut permeability markers (D-lactate and diamine oxidase (DAO)) in the serum were also examined by ELISA.

Results

The results showed that fluoride exposure induced a lower spontaneous exploration (P < 0.05) in T-maze test, which indicated an impairment of memory. Spontaneous exploration of BS15-treated mice was significantly higher (P < 0.05) than that in F group. Fluoride reduced (P < 0.05) levels of myelin structural protein (proteolipid protein) and neurogenesis-associated proteins (brain-derived neurotrophic factor and cAMP/Ca²⁺ responsive element-binding protein), induced disordered inflammatory cytokines (TNF-α, IFN-γ, and IL-6; P < 0.05), increased pro-apoptotic genes (caspase-3; P < 0.05), and decreased anti-apoptotic genes (Bcl-2; P < 0.05) in the hippocampus, of which the influences were reversed by BS15. BS15 treatment exerted significant preventive effects on reversing the gut inflammation induced by excessive fluoride intake by reducing (P < 0.05) the levels of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ)) and remarkably increasing (P < 0.05) the level of anti-inflammatory cytokines (IL-10). Moreover, the serum DAO activity and D-lactate concentration significantly increased by fluoride were also reduced (P < 0.05) by BS15. This result indicated the profitable effect of BS15 on gut permeability.

Conclusion

L. johnsonii BS15 intake could benefit the neuroinflammation and demyelination in the hippocampus by improving the gut environment and ameliorating fluorine-induced memory dysfunction.

Acute aflatoxin B1-induced gastro-duodenal and hepatic oxidative damage is preceded by time-dependent hyperlactatemia in rats

Elevated serum lactate concentration has been used to predict the risk of fatality in various disease states in acutely ill patients or poisoning with different chemicals. However, its utility in predicting disease progression during acute aflatoxicosis has not been investigated. This study was designed to evaluate changes in blood lactate levels following acute exposure to aflatoxin B₁ (AFB₁) and to determine whether changes in blood lactate levels bear any relationship with biochemical and/or morphological lesions in the stomach, duodenum, and liver. Twenty-one male Wistar rats were randomly divided into three groups (n = 7 rats /group) including Group A (control) receiving vehicle alone and Groups B and C treated with single oral doses of AFB₁ at 2.5 and 5 mg/kg, respectively. AFB₁ produced significant (p < 0.05) time- and dose-dependent increase in blood lactate concentration as early as 1 h following its administration, with further increases observed at 3 h and 6 h. The hyperlactatemia accompanied tissue oxidative changes including increased H₂O₂ and MDA, as well as depletion in glutathione, glutathione peroxidase, superoxide dismutase, and total thiols in gastro-duodenal and hepatic tissues. The oxidative changes were reflected in morphological alterations observed at histopathology with more severe lesions observed with the higher dose of AFB₁. Serum levels of pro-inflammatory cytokines (TNF-α and IL-1β) were, however, differently modified by AFB₁ administration. Taken together, the results from this study gives indication that hyperlactatemia may find utility in predicting the severity of tissue damage induced by acute AFB₁ exposure.

Alterations in cecal microbiota and intestinal barrier function of laying hens fed on fluoride supplemented diets

The objective of this study was to investigate the effects of fluorine at levels of 31, 431, 1237 mg/kg feed on cecum microbe, short-chain fatty acids (SCFAs) and intestinal barrier function of laying hens. The results showed that the intestinal morphology and ultrastructure were damaged by dietary high F intake. The mRNA expression levels of zonula occludens-1, zonula occludens-2, claudin-1, and claudin-4 were decreased in jejunum and ileum. However, the concentrations of serum diamine oxidase, and D-lactic acid and intestinal contents of interleukin 1 beta, interleukin 6, and Tumor necrosis factor-alpha were increased. Consistent with this, dietary high F intake altered the cecum microbiota, with increasing the concentration of pathogens, such as Proteobacteria and Escherichia-Shigella, as well as, decreasing the contents of beneficial bacteria, such as Lactobacillus, and expectedly, reduced the SCFAs concentrations. In conclusion, the actual results confirmed that (1) high dietary F intake could damage the intestinal structure and function, with impaired intestinal barrier and intestinal inflammation, and (2) destroy the cecum microbial homeostasis, and decrease the concentrations of SCFAs, which aggravate the incidence of intestinal inflammation in laying hens.

The Gastrointestinal Exertional Heat Stroke Paradigm: Pathophysiology, Assessment, Severity, Aetiology and Nutritional Countermeasures

Exertional heat stroke (EHS) is a life-threatening medical condition involving thermoregulatory failure and is the most severe condition along a continuum of heat-related illnesses. Current EHS policy guidance principally advocates a thermoregulatory management approach, despite growing recognition that gastrointestinal (GI) microbial translocation contributes to disease pathophysiology. Contemporary research has focused to understand the relevance of GI barrier integrity and strategies to maintain it during periods of exertional-heat stress. GI barrier integrity can be assessed non-invasively using a variety of in vivo techniques, including active inert mixed-weight molecular probe recovery tests and passive biomarkers indicative of GI structural integrity loss or microbial translocation. Strenuous exercise is strongly characterised to disrupt GI barrier integrity, and aspects of this response correlate with the corresponding magnitude of thermal strain. The aetiology of GI barrier integrity loss following exertional-heat stress is poorly understood, though may directly relate to localised hyperthermia, splanchnic hypoperfusion-mediated ischemic injury, and neuroendocrine-immune alterations. Nutritional countermeasures to maintain GI barrier integrity following exertional-heat stress provide a promising approach to mitigate EHS. The focus of this review is to evaluate: (1) the GI paradigm of exertional heat stroke; (2) techniques to assess GI barrier integrity; (3) typical GI barrier integrity responses to exertional-heat stress; (4) the aetiology of GI barrier integrity loss following exertional-heat stress; and (5) nutritional countermeasures to maintain GI barrier integrity in response to exertional-heat stress.

Direct Implementation of Intestinal Permeability Test in NMR Metabolomics for Simultaneous Biomarker Discovery-A Feasibility Study in a Preterm Piglet Model

Measurement of intestinal permeability (IP) is often used in the examination of inflammatory gastrointestinal disorders. IP can be assessed by measurement of urinary recovery of ingested non-metabolizable lactulose (L) and mannitol (M). The present study aimed to examine how measurements of IP can be integrated in a NMR-based metabolomics approach for a simultaneous quantification of L/M ratio and biomarker exploration. For this purpose, plasma and urine samples were collected from five-day-old preterm piglets (n = 20) with gastrointestinal disorders (subjected to intra-amniotic lipopolysaccharide (LPS, 1 mg/fetus)) after they had been administrated a 5% lactulose and 5% mannitol solution (15 mL/kg). The collected plasma and urine samples were analyzed by ¹H NMR-based metabolomics. Urine L/M ratio measured by ¹H NMR spectroscopy showed high correlation with the standard measurement of the urinary recoveries by enzymatic assays (r = 0.93, p < 0.05). Partial least squares (PLS) regressions and correlation analyses between L/M ratio and NMR metabolomics data revealed that L/M ratio was positively correlated with plasma lactate, acetate and succinate levels and negatively correlated with urinary hippuric acid and glycine. In conclusion, the present study demonstrated that NMR metabolomics enables simultaneous IP testing and discovery of biomarkers associated with an impaired intestinal permeability.

Effects of Dietary Zeolite Supplementation as an Antibiotic Alternative on Growth Performance, Intestinal Integrity, and Cecal Antibiotic Resistance Genes Abundances of Broilers

The study investigated the effects of dietary zeolite supplementation as an antibiotic alternative on growth performance, intestinal integrity, and cecal antibiotic resistance genes abundances of broilers. One-day-old chicks were assigned into three groups and fed a basal diet or a basal diet supplemented with antibiotics (50 mg/kg) or zeolite (10 g/kg). Antibiotic or zeolite increased (p < 0.05) average daily gain (ADG) from 1 to 42 days and duodenal villus height to crypt depth ratio (VH:CD) at 21 days. Zeolite increased (p < 0.05) ADG and average daily feed intake from 1 to 21 days, jejunal VH:CD at 21 and 42 days, ileal VH and VH:CD at 42 days, zonula occludens-1 mRNA abundance at 21 days, and duodenal occludin mRNA abundance at 42 days, whereas reduced (p < 0.05) jejunal CD and malondialdehyde levels in ileum at 21 days and duodenum at 42 days, serum D-lactic acid and diamine oxidase levels at 42 days, and plasma lipopolysaccharide content at 21 and 42 days. Antibiotics reduced (p < 0.05) duodenal claudin-2 mRNA abundance at 21 days, whereas increased (p < 0.05) cecal tetB abundance at 42 days. These findings suggested that the beneficial effects of zeolite in broilers were more pronounced than that of antibiotics.

Screening and combining serum biomarkers to improve their diagnostic performance in the detection of intestinal barrier dysfunction in patients after major abdominal surgery

Background

The aim of this prospective study was to screen and combine effective biomarkers to improve their diagnostic performance in detecting intestinal barrier dysfunction in patients after major abdominal surgery.

Methods

Patients undergoing major abdominal surgery were enrolled after signing informed consent in this study. The serum concentrations of α-GST, DAO, D-lactate, citrulline and I-FABP were detected 24 hours before and after surgery. The diagnostic performance of five biomarkers on intestinal barrier dysfunction was assessed using logistic regression models and receiver operating characteristic (ROC) curve analyses.

Results

Thirty-nine patients with major abdominal surgery were enrolled in and successfully completed this study. ROC analysis revealed that the sensitivities of D-lactate, citrulline and I-FABP were very high (0.91, 0.91 and 1.00, respectively), but the specificities of these biomarkers were less than 0.70. The sensitivity of DAO was very low [0.25; 95% confidence interval (CI), 0.05-0.57], but its specificity was high (0.92; 95% CI, 0.75-0.99). The accuracies of D-lactate and I-FABP were very high, and the areas under the curves (AUCs) of the biomarkers were 0.84 (95% CI, 0.68-0.93) and 0.81 (95% CI, 0.65-0.92), respectively. Different combinations of five biomarkers were also analysed. The sensitivity, specificity and AUC values of the combination of I-FABP, citrulline and D-lactate were 1.00, 0.74 and 0.89, respectively. These results were similar to those derived from the combination of α-GST, DAO, D-lactate, citrulline and I-FABP (P=1.000).

Conclusions

The combination of serum D-lactic acid, citrulline and I-FABP greatly improved the diagnostic performance for identifying intestinal barrier dysfunction in patients after major abdominal surgery.

Effects of preoperative oral administration of glucose solution combined with postoperative probiotics on inflammation and intestinal barrier function in patients after colorectal cancer surgery

The effects of preoperative oral administration of glucose solution combined with postoperative probiotics on inflammation and intestinal barrier function in patients after colorectal cancer surgery were observed. Sixty patients treated and scheduled to undergo radical resection of colorectal cancer in The Second Affiliated Hospital of Kunming Medical University from March 2017 to December 2017 were selected and randomly divided into the glucose solution group (n=30) and combined probiotics group (n=30). Patients in both groups took orally 12.5% glucose solution before surgery, and those in the combined probiotics group received bifidus-triple viable preparation every day for 7 consecutive days. Changes in endotoxin, insulin-like growth factor-I (IGF-I) concentration, white blood cell count (WBC), C-reactive protein (CRP), D-lactic acid and urinary lactulose/mannitol (L/M) were detected before surgery and at 1, 3 and 7 days after surgery. The general condition was observed and changes in intestinal florae were compared between the two groups. The body temperature was measured every 4 h with an electronic thermometer, and the duration of fever was recorded (from the first day after operation to the time with normal body temperature after operation, axillary temperature <37.4°C), and the average heart rate was recorded by the ECG monitor. In addition, the time of the first anal exsufflation (the time from the beginning of the operation to the first anal exsufflation) was recorded. In the combined probiotics group, the plasma endotoxin, IGF-I concentration, D-lactic acid and urinary L/M levels were significantly lower than those in the glucose solution group (P<0.05). Moreover, the duration of postoperative fever, average heart rate at 7 days after surgery as well as WBC and CRP clinical indexes were obviously shorter and lower in the combined probiotics group than those in the glucose solution group (P<0.05). Therefore, the combined application of probiotics after surgery can effectively improve the imbalance of intestinal flora. In conclusion, preoperative oral administration of glucose solution combined with postoperative probiotics can improve the intestinal barrier function after colorectal cancer surgery, and benefit the recovery of early inflammatory response after surgery.

Poor short-term glycemic control in patients with type 2 diabetes impairs the intestinal mucosal barrier: a prospective, single-center, observational study

Background

To determine the relation between daily glycemic fluturation and the intestinal mucosal barrier dysfunction in type 2 diabetes mellitus (T2DM).

Methods

Totally 66 patients with T2DM were enrolled, 33 healthy volunteers were also recruited according to the enrolled patients’ gender and age in a ratio of 2: 1. Patients were bisected by the median of endotoxins level into low(< 12.31 μ/l, n = 33) and high(≥12.31 μ/l, n = 33) blood endotoxin groups. Clinical data and blood glucose fluctuations were compared between groups. Multivariate regression analysis was used to determine the independent factors affecting the intestinal mucosal barrier.

Results

Serum endotoxin [12.1 (4.2~22.0) vs 3.2 (1.3~6.0), P < 0.001] and fasting blood glucose levels [9.8 ± 3.6 vs 5.4 ± 0.7, P < 0.001] were significantly higher in patients with T2DM than the control group. The standard deviation of blood glucose (SDBG) within 1 day [2.9 (2.0~3.3) vs. 2.1 (1.6~2.5), P = 0.012] and the largest amplitude of glycemic excursions (LAGE) [7.5 (5.4~8.9) vs. 5.9 (4.3~7.4), P = 0.034] were higher in the high endotoxin group than in the low endotoxin group. A multiple linear stepwise regression revealed a positive correlation between SDBG with endotoxin (standard partial regression coefficient = 0.255, P = 0.039).

Conclusions

T2DM patients who incapable of maintaining stable blood glucose level are at a higher risk to associated with intestinal mucosal barrier injury.

Quantitative Measure of Intestinal Permeability Using Blue Food Coloring

BACKGROUND

Loss of intestinal barrier integrity plays a fundamental role in the pathogenesis of various gastrointestinal diseases and is implicated in the onset of sepsis and multiple organ failure. An array of methods to assess different aspects of intestinal barrier function suffers from lack of sensitivity, prolonged periods of specimen collection, or high expense. We have developed a technique to measure the concentration of the food dye FD&C Blue #1 from blood and sought to assess its utility in measuring intestinal barrier function in humans.

MATERIALS AND METHODS

Four healthy volunteers and 10 critically ill subjects in the intensive care unit were recruited in accordance with an institutional review board approved protocol. Subjects were given 0.5 mg/kg Blue #1 enterally as an aqueous solution of diluted food coloring. Five blood specimens were drawn per subject: 0 h (before dose), 1, 2, 4, and 8 h. After plasma isolation, organic extracts were analyzed by high-performance liquid chromatography/mass spectrometry detecting the presence of unmodified dye.

RESULTS

We found no baseline detectable absorption in healthy volunteers. After including the subjects in the intensive care unit, we compared dye absorption in the six subjects who met criteria for septic shock with the eight who did not. Septic patients demonstrated significantly greater absorption of Blue #1 after 2 h.

CONCLUSIONS

We have developed a novel, easy-to-use method to measure intestinal barrier integrity using a food grade dye detectable by mass spectrometry analysis of patient blood following oral administration.

Dietary l -threonine supplementation attenuates lipopolysaccharide-induced inflammatory responses and intestinal barrier damage of broiler chickens at an early age

This study was conducted to investigate the protective effects ofl-threonine (l-Thr) supplementation on growth performance, inflammatory responses and intestinal barrier function of young broilers challenged with lipopolysaccharide (LPS). A total of 144 1-d-old male chicks were allocated to one of three treatments: non-challenged broilers fed a basal diet (control group), LPS-challenged broilers fed a basal diet withoutl-Thr supplementation and LPS-challenged broilers fed a basal diet supplemented with 3·0 g/kgl-Thr. LPS challenge was performed intraperitoneally at 17, 19 and 21 d of age, whereas the control group received physiological saline injection. Compared with the control group, LPS challenge impaired growth performance of broilers, andl-Thr administration reversed LPS-induced increase in feed/gain ratio. LPS challenge elevated blood cell counts related to inflammation, and pro-inflammatory cytokine concentrations in serum (IL-1βand TNF-α), spleen (IL-1βand TNF-α) and intestinal mucosa (jejunal interferon-γ(IFN-γ) and ileal IL-1β). The concentrations of intestinal cytokines in LPS-challenged broilers were reduced byl-Thr supplementation. LPS administration increased circulatingd-lactic acid concentration, whereas it reduced villus height, the ratio between villus height and crypt depth and goblet density in both jejunum and ileum. LPS-induced decreases in jejunal villus height, intestinal villus height:crypt depth ratio and ileal goblet cell density were reversed withl-Thr supplementation. Similarly, LPS-induced alterations in the intestinal mRNA abundances of genes related to intestinal inflammation and barrier function (jejunal toll-like receptor 4,IFN-γand claudin-3, and ilealIL-1βand zonula occludens-1) were normalised withl-Thr administration. It can be concluded thatl-Thr supplementation could attenuate LPS-induced inflammatory responses and intestinal barrier damage of young broilers.

Epithelial Barrier Function in Gut-Bone Signaling

The intestinal epithelial barrier plays an essential role in maintaining host homeostasis. The barrier regulates nutrient absorption as well as prevents the invasion of pathogenic bacteria in the host. It is composed of epithelial cells, tight junctions, and a mucus layer. Several factors, such as cytokines, diet, and diseases, can affect this barrier. These factors have been shown to increase intestinal permeability, inflammation, and translocation of pathogenic bacteria. In addition, dysregulation of the epithelial barrier can result in inflammatory diseases such as inflammatory bowel disease. Our lab and others have also shown that barrier disruption can have systemic effects including bone loss. In this chapter, we will discuss the current literature to understand the link between intestinal barrier and bone. We will discuss how inflammation, aging, dysbiosis, and metabolic diseases can affect intestinal barrier-bone link. In addition, we will highlight the current suggested mechanism between intestinal barrier and bone.

Peritoneal lavage with povidone-iodine solution in colorectal cancer-induced rats

BACKGROUND

Although peritoneal lavage with povidone-iodine (PVPI) is frequently performed after surgery on the gastrointestinal tract, the effects of PVPI on the intestinal epithelial barrier are unknown. The purpose of this study was to investigate the effects of abdominal irrigation with PVPI on the intestinal epithelial barrier in a colorectal cancer (CRC)-induced rat model.

MATERIALS AND METHODS

The CRC model was induced in rats with azoxymethane and dextran sodium sulfate. Next, a total of 24 male CRC-induced rats were randomly divided into three groups (n = 8): (1) a sham-operated group, (2) an NS group (peritoneal lavage 0.9% NaCl), and (3) a PVPI group (peritoneal lavage with 0.45%-0.55% PVPI). The mean arterial pressure was continuously monitored throughout the experiment. The levels of plasma endotoxin and D-lactate, blood gases, and protein concentration were measured. The ultrastructural changes of the epithelial tight junctions were observed by transmission electron microscopy.

RESULTS

The mean arterial pressure after peritoneal lavage was lower in the PVPI group than that in the NS group. The protein concentration and levels of endotoxin and D-lactate were higher in the PVPI group than they were in the PVPI group. In addition, PVPI treatment resulted in a markedly severe metabolic acidosis and intestinal mucosal injury compared with NS rats.

CONCLUSIONS

Peritoneal lavage with PVPI dramatically compromises the integrity of the intestinal mucosa barrier and causes endotoxin shock in CRC rats. It is unsafe for clinical applications to include peritoneal lavage with PVPI in colorectal operations.

Gut-dependent microbial translocation induces inflammation and cardiovascular events after ST-elevation myocardial infarction

BACKGROUND

Post-infarction cardiovascular remodeling and heart failure are the leading cause of myocardial infarction (MI)-driven death during the past decades. Experimental observations have involved intestinal microbiota in the susceptibility to MI in mice; however, in humans, identifying whether translocation of gut bacteria to systemic circulation contributes to cardiovascular events post-MI remains a major challenge.

RESULTS

Here, we carried out a metagenomic analysis to characterize the systemic bacteria in a cohort of 49 healthy control individuals, 50 stable coronary heart disease (CHD) subjects, and 100 ST-segment elevation myocardial infarction (STEMI) patients. We report for the first time higher microbial richness and diversity in the systemic microbiome of STEMI patients. More than 12% of post-STEMI blood bacteria were dominated by intestinal microbiota (Lactobacillus, Bacteroides, and Streptococcus). The significantly increased product of gut bacterial translocation (LPS and D-lactate) was correlated with systemic inflammation and predicted adverse cardiovascular events. Following experimental MI, compromised left ventricle (LV) function and intestinal hypoperfusion drove gut permeability elevation through tight junction protein suppression and intestinal mucosal injury. Upon abrogation of gut bacterial translocation by antibiotic treatment, both systemic inflammation and cardiomyocyte injury in MI mice were alleviated.

CONCLUSIONS

Our results provide the first evidence that cardiovascular outcomes post-MI are driven by intestinal microbiota translocation into systemic circulation. New therapeutic strategies targeting to protect the gut barrier and eliminate gut bacteria translocation may reduce or even prevent cardiovascular events post-MI.

A mixture of Lactobacillus species isolated from traditional fermented foods promote recovery from antibiotic-induced intestinal disruption in mice

AIMS

This study evaluated the antibiotic-induced changes in microbial ecology, intestinal dysbiosis and low-grade inflammation; and the combined effect of four different Lactobacillus species on recovery of microbiota composition and improvement of gut barrier function in mice.

METHODS AND RESULTS

Administration of the antibiotic ampicillin for 2 weeks decreased microbial community diversity, induced caecum tumefaction and increased gut permeability in mice. Application of a probiotic cocktail of four Lactobacillus species (JUP-Y4) modulated the microbiota community structure and promoted the abundance of potentially beneficial bacteria such as Akkermansia. Ampicillin administration led to a decline in Bacteroidetes from 46·6 ± 3·91% to 0·264 ± 0·0362%; the addition of JUP-Y4 restored this to 41·4 ± 2·87%. This probiotic supplementation was more effective than natural restoration, where the levels of Bacteroidetes were only restored to 29·3 ± 2·07%. Interestingly, JUP-Y4 treatment was more effective in the restoration of microbiota in faecal samples than in caecal samples. JUP-Y4 also significantly reduced the levels of d-lactate and endotoxin (lipopolysaccharide, LPS) in the serum of mice, and increased the expression of tight-junction proteins while reducing the production of inflammatory cytokines (TNF-α, IL-6, MCP-1, IFN-γ and IL-1β) in the ileum and the colon of antibiotic-treated mice.

CONCLUSIONS

JUP-Y4 not only promoted recovery from antibiotic-induced gut dysbiosis, but also enhanced the function of the gut barrier, reduced inflammation and lowered levels of circulating endotoxin in mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

Consumption of a mixture of Lactobacillus species may encourage faster recovery from antibiotic-induced gut dysbiosis and gut microbiota-related immune disturbance.

The intestinal barrier: a fundamental role in health and disease

The gastrointestinal mucosa constitutes a critical barrier where millions of microbes and environmental antigens come in close contact with the host immune system. Intestinal barrier defects have been associated with a broad range of diseases and therefore denote a new therapeutic target. Areas covered: This review is based on an extensive literature search in PubMed of how the intestinal barrier contributes to health and as a trigger for disease. It discusses the anatomy of the intestinal barrier and explains the available methods to evaluate its function. Also reviewed is the importance of diet and lifestyle factors on intestinal barrier function, and three prototypes of chronic diseases (inflammatory bowel disease, celiac disease and nonalcoholic fatty liver disease) that have been linked to barrier defects are discussed. Expert commentary: The intestinal barrier has been investigated by various methods, but correlation of results across studies is difficult, representing a major shortcoming in the field. New upcoming techniques and research on the effect of barrier-restoring therapeutics may improve our current understanding of the gut barrier, and provide a step forward towards personalised medicine.

Diagnostic value of arterial blood gas lactate concentration in the different forms of mesenteric ischemia. Eur J Trauma Emerg Surg. 2018;44:265-272. [PMID: 28612169 DOI: 10.1007/s00068-017-0805-7] [Cited by in Crossref: 14] PURPOSEThe role of serum lactate measurement in patients with intestinal ischemia still remains unclear. The aim of this study was to prospectively evaluate the diagnostic performance of arterial blood gas lactate concentrations in the patients with acute mesenteric ischemia and its different forms.METHODSAll the patients reporting abdominal pain associated with risk factors for mesenteric ischemia underwent arterial blood gas and contrast enhanced abdominal computer tomography (CT).RESULTSAt CT, 201 patients (70.7%) showed a nonischemic disease (group 1) and 83 patients (29.2%) showed findings of mesenteric ischemia. Out of these, 35 patients (42.1%) showed bowel ischemia secondary to non vascular causes (group 2) and 48 (57.8%) had a vascular intestinal ischemia (group 3). Out of these, 20 showed small bowel arterial occlusion (group 3a), 13 a small bowel nonocclusive ischemia (group 3b), 7 a venous small bowel occlusion (group 3c) and 8 showed isolated colonic ischemia (group 3d). The median lactate serum level was significantly higher in patients with vascular ischemia if compared with patients with nonischemic disease and secondary mesenteric ischemia (p < 0.0001; Kruskal-Wallis test). The areas under ROC curves for the lactate serum levels in the groups 2, 3, 3a, 3b, 3c and 3d were, respectively, 0.61, 0.85, 0.93, 0.93, 0.68 and 0.67.CONCLUSIONSArterial blood gas lactate levels seem to show good diagnostic accuracy in diagnosing small bowel arterial and nonocclusive ischemia and poor accuracy in diagnosing secondary mesenteric ischemia, small bowel venous ischemia and ischemic colitis

PURPOSE

The role of serum lactate measurement in patients with intestinal ischemia still remains unclear. The aim of this study was to prospectively evaluate the diagnostic performance of arterial blood gas lactate concentrations in the patients with acute mesenteric ischemia and its different forms.

METHODS

All the patients reporting abdominal pain associated with risk factors for mesenteric ischemia underwent arterial blood gas and contrast enhanced abdominal computer tomography (CT).

RESULTS

At CT, 201 patients (70.7%) showed a nonischemic disease (group 1) and 83 patients (29.2%) showed findings of mesenteric ischemia. Out of these, 35 patients (42.1%) showed bowel ischemia secondary to non vascular causes (group 2) and 48 (57.8%) had a vascular intestinal ischemia (group 3). Out of these, 20 showed small bowel arterial occlusion (group 3a), 13 a small bowel nonocclusive ischemia (group 3b), 7 a venous small bowel occlusion (group 3c) and 8 showed isolated colonic ischemia (group 3d). The median lactate serum level was significantly higher in patients with vascular ischemia if compared with patients with nonischemic disease and secondary mesenteric ischemia (p < 0.0001; Kruskal-Wallis test). The areas under ROC curves for the lactate serum levels in the groups 2, 3, 3a, 3b, 3c and 3d were, respectively, 0.61, 0.85, 0.93, 0.93, 0.68 and 0.67.

CONCLUSIONS

Arterial blood gas lactate levels seem to show good diagnostic accuracy in diagnosing small bowel arterial and nonocclusive ischemia and poor accuracy in diagnosing secondary mesenteric ischemia, small bowel venous ischemia and ischemic colitis.

Association between acute gastrointestinal injury and biomarkers of intestinal barrier function in critically ill patients

Background

To assess the associations of biomarkers of intestinal barrier function and other clinical variables with acute gastrointestinal injury (AGI) grade, and of these clinical variables with mortality in critically ill patients.

Methods

This was a single-center, observational, prospective study. Patients were included if they were diagnosed with AGI and underwent tests for the measurement of plasma levels of intestinal fatty acid–binding protein (i-FABP), d-lactate (d-la), and lipopolysaccharide. General characteristics, AGI grades, Acute Physiology and Chronic Health Evaluation (APACHE) II scores, Sepsis-related Organ Failure Assessment (SOFA) scores, intra-abdominal pressure (IAP), and 28-day mortality were recorded and compared among patients with different AGI grades.

Results

Among the 90 included patients, the APACHE II score, IAP, and LPS and D-la levels significantly differed between the four AGI grades. Multinomial logistic regression analysis with grade I as the reference for grades II, III, and IV revealed that high APACHE II scores increased the odds of AGI grade III (odds ratio [OR], 1.754; 95% confidence interval [CI], 1.225–2.511) and grade IV (OR, 1.493; 95% CI, 1.079–2.066). Similarly, IAP increased the odds of AGI grade III (OR, 1.622; 95% CI, 1.111–2.369) and grade IV (OR, 1.518; 95% CI, 1.066–2.162). Elevated D-la increased the odds of AGI grades II (OR, 1.059; 95% CI, 1.005–1.117), III (OR, 1.155; 95% CI, 1.052–2.268), and IV (OR, 1.088; 95% CI, 1.013–1.168). In contrast, i-FABP and LPS did not increase the odds of any AGI grade. SOFA scores could independently predict the odds of death in AGI patients (OR, 1.223; 95% CI, 1.007–1.485).

Conclusion

AGI patients exhibit loss of gastrointestinal barrier function, and d-la could serve as a better marker of AGI grade than i-FABP or lipopolysaccharide.

Intestinal barrier integrity and function in infants with cholestasis

Background/Aims

The safety of the human body is maintained by effective monitoring of the mucosal surface integrity and protection against potentially harmful compounds. This function of the gut called intestinal barrier function can be affected by cholestasis and the absence of bile in the intestinal lumen. We aimed to determine whether the gut barrier integrity is impaired in infants with cholestasis by evaluation of the intestinal fatty acid binding proteins (I-FABP) and ileal bile acid binding protein (I-BABP) as markers of intestinal epithelial cell damage and plasma D-lactate level as a marker of gut wall permeability.

Methods

This case-control study included 53 infants with cholestasis and 29 controls. Serum levels of I-FABP, I-BABP, and D-lactate were measured in all subjects.

Results

Both groups of patients with neonatal hepatitis and biliary atresia showed significantly higher levels of I-FABP and I-BABP than the controls. There were no differences in the serum D-lactate level between the cases and controls. There was no difference between the two groups of patients (I and II) regarding any of the parameters studied. No significant correlations between serum levels of I-FABP, I-BABP, or D-lactate and total or direct bilirubin levels were found in the cholestatic infants.

Conclusions

The intestinal epithelial barrier integrity is breached nearly in all parts of the intestine in infants with cholestasis. Further research is recommended to determine the impact of this finding on the management of these infants. The relationship between physical intestinal barrier damage and its functional failure remains subject for further research.

The complex task of measuring intestinal permeability in basic and clinical science

Intestinal permeability is a key feature of intestinal barrier function. Altered intestinal permeability is described in many chronic diseases and may be a risk factor for disease development and a target for emerging therapeutics. Thus, reliable and sensitive methods to measure intestinal permeability in both the clinical and preclinical setting are needed. There is currently a large array of tests to choose from, each with advantages and disadvantages. When possible, a combination of methods should be used. The choice of tests should be based on a deep understanding of intestinal barrier physiology and the recognition of their limitations. This mini-review will highlight the advantages and limitations associated with intestinal permeability tests and will identify current problems in the field and how they can be addressed in the future.

Bacterial translocation and in vivo assessment of intestinal barrier permeability in rainbow trout (Oncorhynchus mykiss) with and without soyabean meal-induced inflammation

The primary aim of this experiment was to evaluate the intestinal barrier permeability in vivo in rainbow trout (Oncorhynchus mykiss) fed increasing levels of soyabean meal (SBM). The relationship between SBM-induced enteritis (SBMIE) and the permeability markers was also investigated. Our results showed that the mean score of morphological parameters was significantly higher as a result of 37·5 % SBM inclusion in the diet, while the scores of fish fed 25 % SBM or lower were not different from those of the fish meal-fed controls (P < 0·05). SBMIE was found in the distal intestine (DI) in 18 % of the fish (eleven of sixty): ten in the 37·5 % SBM-fed group and one in the 25 % SBM-fed group. Sugar markers in plasma showed large variation among individuals probably due to variation in feed intake. We found, however, a significant linear increase in the level of plasma d-lactate with increasing SBM inclusion level (P < 0·0001). Plasma concentration of endotoxin was not significantly different in groups with or without SBMIE. Some individual fish showed high values of endotoxin in blood, but the same individuals did not show any bacterial translocation. Plasma bacterial DNA was detected in 28 % of the fish with SBMIE, and 8 % of non-SBMIE fish (P = 0·07). Plasma concentration of d-lactate was significantly higher in fish with SBMIE (P < 0·0001). To conclude, SBMIE in the DI of rainbow trout was associated with an increase in bacterial translocation and plasma d-lactate concentration, suggesting that these permeability markers can be used to evaluate intestinal permeability in vivo.

Rebamipide Promotes the Regeneration of Aspirin-Induced Small-Intestine Mucosal Injury through Accumulation of β-Catenin

Background

The effect of rebamipide on repairing intestinal mucosal damage induced by nonsteroidal anti-inflammatory drugs and its mechanism remain unclear. In this study, we sought to explore the mechanism whereby rebamipide could promote the regeneration of aspirin-induced intestinal mucosal damage.

Methods

BALB/c mice were administered aspirin (200 mg/kg/d) for 5 days to induce acute small intestinal injury (SII). Subsequently, SII mice were treated with rebamipide (320 mg/kg/d) for 5 days. The structure of intestinal barrier was observed with transmission electron microscope, and Zo-1 and occludin expressions were detected. The proliferative index was indicated by the percentage of proliferating cell nuclear antigen positive cells. The prostaglandin E₂ (PGE₂) levels in the small intestine tissues were measured by an enzyme immunoassay. The mRNA and protein expression levels of cyclooxygenase (COX) and β-catenin signal were detected in the small intestine using quantitative PCR and Western blot, respectively.

Results

COX expression was significantly down-regulated in aspirin induced SII (P < 0.05). In SII mice treated with rebamipide, histopathological findings of aspirin-induced intestinal inflammation were significantly milder and tight junctions between intestinal epithelial cells were improved significantly. The proliferative index increased after rebamipide treatment when compared with that in the control mice. The expressions of COX-2, β-catenin, and c-myc and the PGE2 concentrations in small intestinal tissues were significantly increased in mice with rebamipide treatments (P < 0.05).

Conclusion

Rebamipide administration in aspirin-induced SII mice could improve the intestinal barrier structure and promote the regeneration of small intestinal epithelial injury through up-regulating COX-2 expression and the accumulation of β-catenin.

Impaired intestinal mucosal barrier upon ischemia-reperfusion: "patching holes in the shield with a simple surgical method"

Mesenteric ischemia-reperfusion (IR) is associated with impairment of the gut barrier function and the initiation of a proinflammatory cascade with life-threatening results. Therefore methods directed to ameliorate IR injury are of great importance. We aimed at describing the effects of postconditioning (PC) on the alterations of the intestinal mucosal function and the inflammatory response upon mesenteric IR. Methods. Male Wistar rats were gavaged with green fluorescent protein-expressing E. coli suspensions. Animals were randomized into three groups (n = 15), sham-operated, IR-, and PC-groups, and underwent 60 minutes of superior mesenteric artery occlusion, followed by 6 hours of reperfusion. Postconditioning was performed at the onset of reperfusion. Blood and tissue samples were taken at the end of reperfusion, for histological, bacteriological, and plasma examinations. Results. The PC-group presented a more favorable claudin-2, claudin-3, claudin-4, and zonula occludens-1 membrane expression profile, and significantly lower rates of bacterial translocation to distant organs and plasma D-lactate levels compared to the IR-group. Histopathological lesions, plasma I-FABP, IL-6, and TNF-α levels were significantly lower in the PC-group compared to the IR-group. Conclusion. The use of postconditioning improved the integrity of the intestinal mucosal barrier upon mesenteric IR, and thus reduced the incidence of bacterial translocation and development of a systemic inflammatory response.

Epidermal growth factor promotes proliferation and improves restoration after intestinal ischemia-reperfusion injury in rats

Epidermal growth factor (EGF) is an attractive and promising therapeutic application for intestinal disorders. The current study examined its influence on proliferation and restoration after ischemia-reperfusion (I/R) injury in rat small intestine. Six groups were performed: sham operation (Con); ischemia for 30 min with subsequent reperfusion for 30 min (I/R); I/R injured with 500 μg/kg EGF injected 5 min before ischemia (Pre-l); I/R injured with 50 μg/kg EGF injected 5 min before ischemia (Pre-s); I/R injured with 500 μg/kg EGF injected 5 min after reperfusion (Post-l); and I/R injured with 50 μg/kg EGF injected 5 min after reperfusion (Post-s). Intestinal histological damage, crypt cell proliferation degree, mucosal permeability, tight junction proteins expression, and levels of inflammation factors were studied for each group. Compared with the I/R group, administration of EGF in the Pre-l, Pre-s, and Post-l groups all presented a significant proliferation effect. The levels of FD4, IL-6, and TNF-α were dramatically decreased in all EGF-treated groups. Histological destruction was improved and TJs recovery was notably accelerated in all EGF-treated groups except the Post-s group. D-lactate concentration was only diminished in the Pre-l group. These results suggest that mucosally applied EGF can promote intestinal proliferation and improve restoration after I/R injury. EGF intraluminal administration is an effective treatment against intestinal I/R injury.

Intravenous administration of tetramethylpyrazine reduces intestinal ischemia-reperfusion injury in rats

Intestinal ischemia-reperfusion injury (IIRI) is a life-threatening condition requiring prompt medical intervention. Tetramethylpyrazine (TMP) is a biologically active alkaloid isolated from Ligusticum wallichii. Previously, it was shown that TMP causes vasodilatation and inhibition of platelet aggregation as well as exhibits significant antioxidant effects. Therefore, the aim of the present study was to evaluate possible therapeutic effects of TMP in the prevention of IIRI. Wistar rats (n = 80) were randomly divided into eight experimental groups and subjected to a 1 h occlusion of cranial mesenteric artery followed by 0, 1, 12, and 24 h period of reperfusion. Thirty minutes before the IIRI animals received either TMP (30 mg/kg, i.v.) or identical volume of saline. In addition, a control group of 10 animals was not exposed to IIRI. Intestine morphology was evaluated by using histopathological injury index examination (HII), goblet and Paneth cells quantification as well as by applying immunofluorescent methods such as InSitu TUNEL and caspase-3 positivity assessment. Here we showed that preconditioning with TMP prior IIRI decreases the grade of injury. Significant reduction of HII was detected in TMP pretreated groups after 0, 1, and 12 h of reperfusion where injury reduction up to 75% was found. Lower histopathological damage in preconditioned groups was accompanied with increased number of secretory epithelial cells and decreased number of apoptotic cells. These results demonstrate the protective effect of TMP on the small intestine mucosa, suggesting administration of TMP as a molecule for pharmacological intervention against IIRI.