Plasma postheparin diamine oxidase. Sensitive provocative test for quantitating length of acute intestinal mucosal injury in the rat

Effect of Supplementation with Black Soldier Fly Extract on Intestinal Function in Piglets Infected with Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea virus (PEDV) has developed as a global problem for the pig business, resulting in significant financial losses. Black soldier fly extract (BFE) has been proven to improve intestinal growth in pigs after weaning. Consequently, the goal of the present investigation was to explore the effects of BFE supplementation on intestinal function in PEDV-infected piglets. Eighteen piglets were randomly allocated to three groups: control, PEDV, and BFE + PEDV. The piglets in the BFE + PEDV group received 500 mg/kg BW of BFE orally for seven days from day 4 to 10 of the study. On day 9 of the study, six pigs from each group received either clean saline or PEDV solution at a dosage of 106 TCID50 (50% tissue culture infectious dose) per pig. On day 11, samples of blood and intestine were taken for additional investigation. The results indicated a significant decrease in the average daily gain (ADG) of piglets infected with PEDV (p < 0.05). Additionally, PEDV infection led to an alteration of blood indexes and a reduction in plasma D-xylose concentration and villi height in the small intestine, while it increased plasma diamine oxidase activity and small intestinal crypt depth in piglets (p < 0.05). The PEDV infection significantly reduced antioxidant enzyme activity in plasma and the gut, including total superoxide dismutase and catalase, while increasing contents of oxidation-relevant products such as malondialdehyde and hydrogen peroxide in piglets. Moreover, PEDV infection increased the mRNA expression level of antiviral-related genes (p < 0.05). Nutritional supplementation with BFE improved intestinal histomorphological indicators and reduced oxidative stress produced by PEDV infection in piglets. Interestingly, BFE could significantly promote the mRNA expression level of antiviral-related genes in the ileum (p < 0.05). Overall, the preliminary results suggest that dietary BFE could improve intestinal function in piglets after PEDV infection. Currently, the findings put a spotlight on the role of BFE in the prevention and treatment of PED in piglets.

Nanoplastics Affect the Bioaccumulation and Gut Toxicity of Emerging Perfluoroalkyl Acid Alternatives to Aquatic Insects (Chironomus kiinensis): Importance of Plastic Surface Charge

Persistent organic pollutants (POPs) have been widely suggested as contributors to the aquatic insect biomass decline, and their bioavailability is affected by engineered particles. However, the toxicity effects of emerging ionizable POPs mediated by differentially charged engineered nanoparticles on aquatic insects are unknown. In this study, 6:2 chlorinated polyfluoroalkyl ether sulfonate (F-53B, an emerging perfluoroalkyl acid alternative) was selected as a model emerging ionizable POP; the effect of differentially charged nanoplastics (NPs, 50 nm, 0.5 g/kg) on F-53B bioaccumulation and gut toxicity to Chironomus kiinensis were investigated through histopathology, biochemical index, and gut microbiota analysis. The results showed that when the dissolved concentration of F-53B remained constant, the presence of NPs enhanced the adverse effects on larval growth, emergence, gut oxidative stress and inflammation induced by F-53B, and the enhancement caused by positively charged NP-associated F-53B was stronger than that caused by the negatively charged one. This was mainly because positively charged NPs, due to their greater adsorption capacity and higher bioavailable fraction of associated F-53B, increased the bioaccumulation of F-53B in larvae more significantly than negatively charged NPs. In addition, positively charged NPs interact more easily with gut biomembranes and microbes with a negative charge, further increasing the probability of F-53B interacting with gut biomembranes and microbiota and thereby aggravating gut damage and key microbial dysbacteriosis related to gut health. These findings demonstrate that the surface charge of NPs can regulate the bioaccumulation and toxicity of ionizable POPs to aquatic insects.

Effects of monolaurin on intestinal barrier, blood biochemical profile, immunity and antioxidant function in porcine epidemic diarrhoea virus-infected piglets

The effects of monolaurin (ML) on the health of piglets infected with porcine epidemic diarrhoea virus (PEDV) have not been fully understood. This study aimed to investigate its role in blood biochemical profile, intestinal barrier function, antioxidant function and the expression of antiviral genes in piglets infected with PEDV. Thirty-two piglets were randomly divided into four groups: control group, ML group, PEDV group and ML + PEDV group. Piglets were orally administrated with ML at a dose of 100 mg/kg·BW for 7 d before PEDV infection. Results showed that PEDV infection significantly decreased D-xylose content and increased intestinal fatty acid-binding protein content, indicating that PEDV infection destroyed intestinal barrier and absorption function. While it could be repaired by ML administration. Moreover, ML administration significantly decreased plasma blood urea nitrogen and total protein content upon PEDV infection. These results suggested ML may increase protein utilisation efficiency. ML administration significantly decreased the number of large unstained cells and Hb and increased the number of leucocytes and eosinophils in the blood of PEDV-infected piglets, indicating ML could improve the immune defense function of the body. In the presence of PEDV infection, ML administration significantly increased superoxide dismutase and catalase activities in blood and colon, respectively, indicating ML could improve antioxidant capacity. Besides, ML administration reversed the expression of ISG15, IFIT3 and IL-29 throughout the small intestine and Mx1 in jejunum and ileum, indicating the body was in recovery from PEDV infection. This study suggests that ML could be used as a kind of feed additive to promote swine health upon PEDV infection.

Differentially Charged Nanoplastics Induce Distinct Effects on the Growth and Gut of Benthic Insects (Chironomus kiinensis) via Charge-Specific Accumulation and Perturbation of the Gut Microbiota

Nanoplastics (NPs), as an emerging contaminant, have usually been found charged in the environment, posing threats to aquatic animals. However, the underlying mechanisms governing the gut toxicity of differentially charged NPs to benthic insects are not well understood. In this study, the gut toxicity in larvae of Chironomus kiinensis exposed to negatively charged NPs (PS-COOH, 50 nm) and positively charged NPs (PS-NH₂, 50 nm) at 0.1 and 1 g/kg was investigated through fluorescence imaging, histopathology, biochemical approaches, and 16S rRNA sequencing. The results showed that PS-NH₂ caused more adverse effect on the larval growth performance and induced more severe oxidative stress, epithelial damage, and inflammatory responses in the gut than PS-COOH. The stronger impact caused by PS-NH₂ was because the gut accumulated PS-NH₂ more readily than PS-COOH for its negatively charged cell membrane. In addition, PS-NH₂ were less agglomerated compared with PS-COOH, leading to an increased interaction with gut cell membranes and microbiota. Furthermore, alpha diversity and relative abundance of the keystone microbiota related to gut barrier and nutrient absorption were markedly lower exposed to PS-NH₂ than PS-COOH, indirectly exacerbating stronger gut and growth damage. This study provides novel insights into the effect mechanisms underlying differentially charged NPs on benthic insects.

Advances in the Clinical Application of Histamine and Diamine Oxidase (DAO) Activity: A Review

The serum level of diamine oxidase (DAO) reflects the integrity and maturation of the small intestinal mucosa. This measure is important in diagnosing various diseases, including chronic urticaria tachyphylaxis, multiple organ dysfunction syndrome, preterm abortion, and migraine. This review aimed to summarize the findings of previous studies on the changes in DAO levels in diverse diseases and the application of this enzyme in the clinical setting, as well as the roles of this enzyme under physiological and pathological conditions. The advances in the mechanism and clinical application of DAO presented in this review will contribute to a better understanding of this enzyme and open up new and broader perspectives for future basic research and clinical applications.

Morphological Assessment and Biomarkers of Low-Grade, Chronic Intestinal Inflammation in Production Animals

Simple Summary

Production animals are continuously exposed to environmental and dietary factors that might induce a state of low-grade, chronic intestinal inflammation. This condition compromises the productive performance and well-fare of these animals, requiring studies to understand what causes it and to develop control strategies. An intestinal inflammatory process is generally associated with alterations in the structure and functionality of its wall, resulting in the release of cellular components into the blood and/or feces. These components can act as biomarkers, i.e., they are measured to identify and quantify an inflammatory process without requiring invasive methods. In this review we discuss the mechanisms of low-grade inflammation, its effects on animal production and sustainability, and the identification of biomarkers that could provide early diagnosis of this process and support studies of useful interventional strategies.

Abstract

The complex interaction between the intestinal mucosa, the gut microbiota, and the diet balances the host physiological homeostasis and is fundamental for the maximal genetic potential of production animals. However, factors such as chemical and physical characteristics of the diet and/or environmental stressors can continuously affect this balance, potentially inducing a state of chronic low-grade inflammation in the gut, where inflammatory parameters are present and demanding energy, but not in enough intensity to provoke clinical manifestations. It’s vital to expand the understanding of inflammation dynamics and of how they compromise the function activity and microscopic morphology of the intestinal mucosa. These morphometric alterations are associated with the release of structural and functional cellular components into the feces and the blood stream creating measurable biomarkers to track this condition. Moreover, the identification of novel, immunometabolic biomarkers can provide dynamic and predictors of low-grade chronic inflammation, but also provide indicators of successful nutritional or feed additive intervention strategies. The objective of this paper is to review the mechanisms of low-grade inflammation, its effects on animal production and sustainability, and the biomarkers that could provide early diagnosis of this process and support studies of useful interventional strategies.

Effects of dietary Bopu powder supplementation on intestinal development and microbiota in broiler chickens

This study aimed to investigate the effect of dietary supplementation with Bopu powder on intestinal development and bacterial community composition in broiler chickens. A total of 486 1-day-old arbor acres broilers were fed a basal diet (CON group), a basal diet supplemented with 50 mg/kg aureomycin (AB group), or a basal diet supplemented with 40 mg/kg Bopu powder (BP group). The results showed that the BP group had significantly lower serum tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and diamine oxidase concentrations and had significantly higher serum IL-10 concentrations than CON group (p < 0.05). Groups AB and BP had a significantly higher weight per unit length of the small intestine and villus height than the CON group (p < 0.05), and BP group had a significantly higher ratio of villus height to crypt depth than groups CON and AB (p < 0.05). Compared to the CON group, dietary Bopu powder or aureomycin supplementation significantly increased transforming growth factor-α concentration and mRNA expressions of zonula occludens-1 (ZO-1) and occludin, and decreased intestinal mucosal concentrations of TNF-α, IL-6, IL-10, caspase-3, and caspase-8 and mRNA expressions of nuclear factor-kappa-B and Bax/Bcl-2 ratio in the intestinal mucosa (p < 0.05). Meanwhile, BP group had significantly higher ZO-1, secretory immunoglobulin A, interferon-γ concentrations, and mRNA expressions of glucose transporter type-2 and sirtuin-1, and significantly lower IL-1β concentration than groups CON and AB in intestinal mucosa (p < 0.05). Dietary Bopu powder supplementation significantly increased the concentration of trefoil factor family member and mRNA expressions of superoxide dismutase-1 and bcl-2 associated X, and significantly reduced casepase-9 concentration and myeloid differentiation primary response-88 expression in the intestinal mucosa of broiler chickens relative to CON group (p < 0.05). Moreover, results of high-throughput sequencing showed that broilers in the BP group had microbial community structure distinct from that in CON group, and the addition of Bopu powder increased the abundances of Faecalibacterium and Colidextribacter (p < 0.05). Therefore, our study suggests a synergic response of intestinal development and microbiota to the Bopu powder, and provides a theoretical basis as a potential substitute for antibiotics.

Toward Oral Supplementation of Diamine Oxidase for the Treatment of Histamine Intolerance

A new diamine oxidase (DAO-1) was discovered recently in the yeast Yarrowia lipolytica PO1f and investigated for its histamine degradation capability under simulated intestinal conditions. DAO-1 was formulated together with catalase as a sucrose-based tablet. The latter (9 × 7 mm; 400 mg) contained 690 nkat of DAO-1 activity, which was obtained from a bioreactor cultivation of a genetically modified Y. lipolytica with optimized downstream processing. The DAO-1 tablet was tested in a histamine bioconversion experiment under simulated intestinal conditions in the presence of food constituents, whereby about 30% of the histamine was degraded in 90 min. This amount might already be sufficient to help people with histamine intolerance. Furthermore, it was found that the stability of DAO-1 in a simulated intestinal fluid is influenced distinctively by the presence of a food matrix, indicating that the amount and type of food consumed affect the oral supplementation with DAO. This study showed for the first time that a microbial DAO could have the potential for the treatment of histamine intolerance by oral supplementation.

Dietary Seleno-l-methionine Alters the Microbial Communities and Causes Damage in the Gastrointestinal Tract of Japanese Medaka Oryzias latipes

Excess dietary seleno-l-methionine (Se-Met) induces various adverse effects in fish inhabiting the Se-contaminated environments. However, there is an extreme paucity of data on the effects of excess dietary Se-Met on the microbiota in the gastrointestinal (GI) tract in fish. In this study, Japanese medaka Oryzias latipes (three months old) were fed the Se-Met enriched diets at environmentally relevant concentrations: 2.90 (Control: (C), 6.69 (L), 11.89 (M), and 27.05 (H) μg Se/g dw) for 60 d. Histopathological, high throughput sequencing, and biochemical approaches were used to investigate the alterations in histology and microbial communities of the GI tract, enzymatic activity, and transcripts of closely related genes. The results showed that the fish weight was reduced at ∼13% from the L and H treatments. Decreased height and thickness of villus in the GI tract were observed in the H treatment. Meanwhile, the level of D-lactate and activity of diamine oxidase (DAO), protease, and lipase were inhibited in the H treatment. The transcripts of the genes related to the inflammation (i.e., IL-1β and IL-8) were elevated, while those of the genes related to the intestinal barrier (i.e., cdh1, ZO-1, ocln, and cldn7) were inhibited in the H treatment. In addition, alpha diversity at the genus level was higher in the L treatment than the control, and the composition of the microbial community was altered by dietary Se-Met. Furthermore, 5 genera (Rhodobacter, Cloacibacterium, Bdellovibrio, Shinella, and Aeromonas) exhibited the largest variation in abundance among treatments. This study has demonstrated that excess dietary Se-Met inhibits growth, causes hispathological damage to the GI tract, and alters the composition of the microbial community in Oryzias latipes.

Fecal microbiota from children with vitamin A deficiency impair colonic barrier function in germ-free mice: The possible role of alterative bile acid metabolites

OBJECTIVE

This study explores the effects of fecal microbiota from children with vitamin A (VA) deficiency on colonic mucosal barrier function.

METHODS

The composition of gut microbes was identified in children with different VA levels, then feces from children with normal VA or VA deficiency was collected separately and transplanted into germ-free (GF) mice, respectively. Three weeks after transplantation, the colon morphology, colonic tight junction proteins, gut microbes, and metabolites were evaluated.

RESULTS

In children, Bifidobacterium and Bacteroides were positively correlated with VA levels. Colonization of VA deficiency fecal microbiota markedly impaired colonic development in GF mice, down-regulated colonic tight junction-related proteins occludin and claudin-1, and reduced immunoglobulin A secretion. Furthermore, fecal microbiota transplantation with different VA levels altered composition of gut microbes and bile acid metabolism pathways in GF mice.

CONCLUSION

These data suggest that fecal microbiota from children with VA deficiency attenuates colonic barrier function in GF mice, which may be achieved by changing the bile acid metabolic pathways.

Aflatoxin B1 and Aflatoxin M1 Induce Compromised Intestinal Integrity through Clathrin-Mediated Endocytosis

With the growing diversity and complexity of diet, humans are at risk of simultaneous exposure to aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1), which are well-known contaminants in dairy and other agricultural products worldwide. The intestine represents the first barrier against external contaminants; however, evidence about the combined effect of AFB1 and AFM1 on intestinal integrity is lacking. In vivo, the serum biochemical parameters related to intestinal barrier function, ratio of villus height/crypt depth, and distribution pattern of claudin-1 and zonula occluden-1 were significantly affected in mice exposed to 0.3 mg/kg b.w. AFB1 and 3.0 mg/kg b.w. AFM1. In vitro results on differentiated Caco-2 cells showed that individual and combined AFB1 (0.5 and 4 μg/mL) and AFM1 (0.5 and 4 μg/mL) decreased cell viability and trans-epithelial electrical resistance values as well as increased paracellular permeability of fluorescein isothiocyanate-dextran in a dose-dependent manner. Furthermore, AFM1 aggravated AFB1-induced compromised intestinal barrier, as demonstrated by the down-regulation of tight junction proteins and their redistribution, particularly internalization. Adding the inhibitor chlorpromazine illustrated that clathrin-mediated endocytosis partially contributed to the compromised intestinal integrity. Synergistic and additive effects were the predominant interactions, suggesting that these toxins are likely to have negative effects on human health.

Gut Microbiological Disorders Reduce Semen Utilization Rate in Duroc Boars

Although rising evidence suggests that the gut microbiota is closely related to host health, the effects of gut microbiota on male fertility are still rarely explored. This study was to investigate the gut microbiota composition and function, fecal short-chain fatty acids (SCFA), intestinal permeability, and systemic inflammatory status of Duroc boar with high (H group, 100%) and low (L group, <80%) semen utilization rate. Fecal samples, analyzed by 16S ribosomal RNA gene sequencing, displayed taxonomic and functional changes between boars with high and low semen utilization rates. For the gut microbiota composition of the boars, four genera were different between the two groups. The [Ruminococcus] and Sphingobium were enriched in L group boars, then negatively correlated with the semen utilization rate. While RFN20 and Paludibacter were enhanced in the H group, only RFN20 showed a significantly positive correlation with the semen utilization rate of boars. In addition, changes in the metabolic function of the gut microbiota of the two groups were found, including altered branched-chain fatty acid (BCFA) production. Significant increases in plasma endotoxin, zonulin, diamine oxidase, and lipocalin-2 levels were observed in boars with low semen utilization, and also, a similar trend in IL-6 and TNF-α was found. However, the concentration of IL-10 in plasma of boars with high semen utilization rate showed an increasing tendency. These results indicated increased intestinal permeability and systemic inflammation in boars with low semen utilization. Data showed that the composition and functions of gut microbiota varied between boars with high or low semen utilization rates, while the semen utilization rate is notably correlated with the gut microbiota composition, intestinal permeability, and inflammatory status of the boar.

Glucagon-like peptide 2 attenuates intestinal mucosal barrier injury through the MLCK/pMLC signaling pathway in a piglet model

Glucagon-like peptide-2 (GLP-2), an intestinotrophic hormone, has drawn considerable attention worldwide due to its potential to promote intestinal development. We investigated the effects and mechanisms of GLP-2 against lipopolysaccharide (LPS)-induced intestinal inflammation and injury both in vitro and in vivo. Forty healthy piglets weaned at the age of 28 days with similar body weight (BW) were assigned to four in vivo treatments with ten piglets each: (i) nonchallenged control; (ii) LPS-challenged control; (iii) LPS + low dose GLP-2; and (iv) LPS + high dose GLP-2. Piglets were subcutaneously injected with phosphate-buffered saline supplemented with GLP-2 at doses of 0, 0, 2, and 10 nmol/kg BW per day for seven consecutive days. The piglets were challenged with an intraperitoneal injection with 100 μg/kg LPS on day 14 to induce intestinal damage. After that, the gene and protein expression levels of representative tight junction proteins and myosin light-chain kinase (MLCK)/phosphorylated myosin light chain (pMLC), as well as proinflammatory cytokine levels were determined using quantitative reverse transcription polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay methods. A high dose of GLP-2 pretreatment increased intestinal permeability by downregulating and redistributing tight junction proteins (p < .05), for example, zona occluden-1 (ZO-1) and occludin. GLP-2 decreased the transcription of proinflammatory cytokines genes including interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α in small intestines (p < .05). GLP-2 prevented the LPS-induced increase in the expression of MLCK dose-dependently and the increase in pMLC levels in the duodenum, jejunum, and ileum. To assess further the protective effect of GLP-2 on LPS-induced intestinal barrier injury after weaning and its possible mechanism, an in vitro intestinal epithelial barrier model was established with IPEC-J2 monolayers and treated with 100 μg/ml LPS with or without 1 × 10^-8  mol/L GLP-2 pretreatment. The in vitro analysis included control, LPS, and GLP-2 + LPS treatments. GLP-2 treatment alleviated the destructive effect of LPS on barrier permeability by restoring the expression and ultrastructure of ZO-1 and occludin (p < .05). In addition, GLP-2 reversed the LPS-induced MLCK hyperexpression and pMLC hyperphosphorylation (p < .05). Taken together, our findings revealed a mechanism by which GLP-2 alleviated LPS-challenged intestinal barrier injury and inflammation in weaned piglets and IPEC-J2 cells via the MLCK/pMLC signaling pathway.

Dietary pterostilbene supplementation attenuates intestinal damage and immunological stress of broiler chickens challenged with lipopolysaccharide

The present study explored the potential effect of pterostilbene as a prophylactic treatment on the lipopolysaccharide (LPS)-induced intestinal injury of broiler chickens by monitoring changes in mucosal injury indicators, redox status, and inflammatory responses. In total, 192 one-day-old male Ross 308 broiler chicks were randomly divided into four groups. This trial consisted of a 2 × 2 factorial design with a diet factor (supplemented with 0 or 400 mg/kg pterostilbene from 1 to 22 d of age) and a stress factor (intraperitoneally injected with saline or LPS at 5.0 mg/kg BW at 21 da of age). The results showed that LPS challenge induced a decrease in BW gain (P < 0.001) of broilers during a 24-h period postinjection; however, this decrease was prevented by pterostilbene supplementation (P = 0.031). Administration of LPS impaired the intestinal integrity of broilers, as indicated by increased plasma diamine oxidase (DAO) activity (P = 0.014) and d-lactate content (P < 0.001), reduced jejunal villus height (VH; P < 0.001) and the ratio of VH to crypt depth (VH:CD; P < 0.001), as well as a decreased mRNA level of jejunal tight junction protein 1 (ZO-1; P = 0.002). In contrast, pterostilbene treatment increased VH:CD (P = 0.018) and upregulated the mRNA levels of ZO-1 (P = 0.031) and occludin (P = 0.024) in the jejunum. Consistently, pterostilbene counteracted the LPS-induced increased DAO activity (P = 0.011) in the plasma. In addition, the LPS-challenged broilers exhibited increases in nuclear accumulation of nuclear factor kappa B (NF-κB) p65 (P < 0.001), the protein content of tumor necrosis factor α (P = 0.033), and the mRNA abundance of IL-1β (P = 0.042) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3; P = 0.019). In contrast, pterostilbene inhibited the nuclear translocation of NF-κB p65 (P = 0.039) and suppressed the mRNA expression of IL-1β (P = 0.003) and NLRP3 (P = 0.049) in the jejunum. Moreover, pterostilbene administration induced a greater amount of reduced glutathione (P = 0.017) but a lower content of malondialdehyde (P = 0.023) in the jejunum of broilers compared with those received a basal diet. Overall, the current study indicates that dietary supplementation with pterostilbene may play a beneficial role in alleviating the intestinal damage of broiler chicks under the conditions of immunological stress.

Palygorskite Supplementation Improves Growth Performance, Oxidative Status, and Intestinal Barrier Function in Cherry Valley Ducks

The effects of dietary palygorskite (Pal) supplementation on growth performance, oxidative status, and intestinal barrier function in ducks were investigated. In total, 720 one-day-old Cherry Valley ducks were categorized into 4 treatments comprising 6 replicates with 30 ducks each. Ducks were fed a basal diet supplemented with 0, 5, 10, or 20 g/kg Pal for 42 days. Twenty-four ducks (1 male/replicate) were slaughtered at 14 and 42 days and samples were collected for analysis. Pal supplementation quadratically increased weight gain and linearly and quadratically increased feed intake (P<0.05) during the starter period. Pal enhanced serum glutathione peroxidase activity (GSHPx) at 14 (linear and quadratic, P<0.05) and 42 days (linear, P<0.001), and lowered serum malondialdehyde (MDA) content at 14 and 42 days (quadratic, P<0.05). It enhanced 42-day liver superoxide dismutase activity (linear, P=0.003) and GSH-Px activity at 14 (quadratic, P=0.044) and 42 days (linear and quadratic, P<0.001), but decreased 14-day liver MDA content (quadratic, P=0.003). Pal reduced 42-day serum diamine oxidase activity (linear and quadratic, P<0.05) and serum endotoxin content at 14 (linear and quadratic, P<0.05) and 42 days (quadratic, P=0.017). It linearly and quadratically increased jejunal mucosal immunoglobulin (Ig) M at 42 days and IgG at 14 and 42 days, and 42-day ileal mucosal IgG and secretory IgA (P<0.05). Ileal mucosal IgM content was quadratically increased at 14 and 42 days (P<0.05) by Pal. Moreover, Pal enhanced the mRNA expression of 14-day occludin in the jejunal mucosa (quadratic, P=0.033) and that of 42-day zonula occludens-1 in the ileal mucosa (linear, P=0.027). Thus, dietary Pal supplementation exerts beneficial effects through improving growth performance, antioxidant capacity, and intestinal barrier function of ducks.

Corn gluten meal induces enteritis and decreases intestinal immunity and antioxidant capacity in turbot (Scophthalmus maximus) at high supplementation levels

Corn gluten meal (CGM) is an important alternative protein source in aquafeed production. However, in turbot (Scophthalmus maximus), CGM could not be effectively utilized because of its low digestibility, the reason for which is still unclear. The purpose of the present study was to investigate and elucidate the cause for the poor utilization of CGM by turbot from the view of gut health. An 8-week feeding trial was conducted with turbot individuals (initial body weight 11.4 ± 0.2 g), which were fed with one of four isonitrogenous and isolipidic diets formulated to include 0%, 21.2%, 31.8%, and 42.6% CGM to progressively replace 0%, 33%, 50%, and 67% fish meal (FM) protein in a FM-based diet, respectively. The results showed that CGM caused dose-dependent decreases in (1) growth performance, nutrient digestibility, and feed utilization; (2) activities of brush-border membrane enzymes; (3) intestinal antioxidant indices of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase activities, and reduced glutathione level; (4) intestinal immune parameters of acid phosphatase activity, complement 3, complement 4, and IgM concentrations. Dose-dependent increases in the severity of the inflammation, with concomitant alterations on microvilli structure and increasing expression of inflammatory cytokine genes of Il-1β, Il-8, and Tnf-α were observed but without a change in the intracellular junctions and the epithelial permeability established by the plasma diamine oxidase activity and D-lactate level examinations. In conclusion, the present work proved that CGM negatively affected the gut health of turbot by inducing enteritis and by decreasing intestinal immunity and antioxidant capacity, which could be one of the reasons for the reduced utilization of CGM by turbot.

Deoxynivalenol Impairs Porcine Intestinal Host Defense Peptide Expression in Weaned Piglets and IPEC-J2 Cells

Host defense peptides (HDPs) are efficient defense components of the innate immune system, playing critical roles in intestinal homeostasis and protection against pathogens. This study aims to investigate the interference effects of DON on the intestinal porcine HDPs expression in piglets and intestinal porcine epithelial cell line (IPEC-J2) cells, and elucidate the underlying mechanisms through which it functions. In an animal experiment, intestinal HDPs were determined in weaned piglets fed control and 1.28 mg/kg or 2.89 mg/kg DON-contaminated diets. Dietary exposure to DON significantly decreased piglet average daily gain, increased intestinal permeability and depressed the expression of porcine β-defensin1 (pBD1), pBD2, pBD3, epididymis protein 2 splicing variant C (pEP2C), PMAP23, and proline/arginine-rich peptide of 39 amino acids (PR39) in the intestine (p < 0.05). In IPEC-J2 cells, DON decreased cell viability and inhibited the expression of pBD1, pBD3, pEP2C, PG1-5, and PR39 (p < 0.05). NOD2, key regulator that is responsible for HDPs production, was markedly downregulated, whereas caspase-12 was activated in the presence of DON. In conclusion, DON induced caspase-12 activation and inhibited the NOD2-mediated HDPs production, which led to an impaired intestinal barrier integrity of weaned piglets. Our study provides a promising target for future therapeutic strategies to prevent the adverse effects of DON.

N-Acetylcysteine protects against intrauterine growth retardation-induced intestinal injury via restoring redox status and mitochondrial function in neonatal piglets

PURPOSE

Intrauterine growth retardation (IUGR) is detrimental to the intestinal development of neonates, yet satisfactory treatment strategies remain limited. This study was, therefore, conducted using neonatal piglets as a model to investigate the potential of N-acetylcysteine (NAC) to alleviate intestinal damage caused by IUGR.

METHODS

Seven normal birth weight (NBW) and fourteen IUGR neonatal male piglets were selected and then fed a basal milk diet (NBW-CON and IUGR-CON groups) or a basal milk diet supplemented with 1.2 g NAC per kg of diet (IUGR-NAC group) from 7 to 21 days of age (n = 7). Parameters associated with the severity of intestinal injury, villus morphology and ultrastructural structure, redox status, and mitochondrial function were analyzed.

RESULTS

Compared with the NBW-CON piglets, the IUGR-CON piglets exhibited decreased villus height and greater numbers of apoptotic cells in jejunum, along with the increases in malondialdehyde and protein carbonyl concentrations and a decreased adenosine triphosphate (ATP) content. Treatment with NAC significantly increased jejunal superoxide dismutase activity, reduced glutathione: oxidized glutathione ratio, and the mRNA abundance of nuclear respiratory factor 2, heme oxygenase 1, and superoxide dismutase 2 in the IUGR-NAC piglets compared with the IUGR-CON piglets. In addition, NAC improved the efficiency of mitochondrial oxidative metabolism and ATP generation, ameliorated mitochondrial swelling, and inhibited the overproduction of mitochondrial superoxide anion in the jejunal mucosa.

CONCLUSIONS

Dietary supplementation of NAC shows promise for attenuating the early intestinal injury of young piglets with IUGR, probably through its antioxidant action to restore redox status and mitochondrial function.

Maternal Soluble Fiber Diet during Pregnancy Changes the Intestinal Microbiota, Improves Growth Performance, and Reduces Intestinal Permeability in Piglets

Increasing evidence suggests that maternal diet during pregnancy modifies an offspring's microbiota composition and intestinal development in a long-term manner. However, the effects of maternal soluble fiber diet during pregnancy on growth traits and the developing intestine are still underexplored. Sows were allocated to either a control or 2.0% pregelatinized waxy maize starch plus guar gum (SF) dietary treatment during gestation. Growth performance, diarrhea incidence, gut microbiota composition and metabolism, and gut permeability and inflammation status of 14-day-old suckling piglets were analyzed. The maternal SF diet improved the growth rate and decreased the incidence of diarrhea in the piglets. Next-generation sequencing analysis revealed that the intestinal microbiota composition was altered by a maternal SF diet. The fecal and plasma levels of acetate and butyrate were also increased. Furthermore, a maternal SF diet reduced the levels of plasma zonulin and fecal lipocalin-2 but increased the plasma concentrations of interleukin 10 (IL-10) and transforming growth factor β (TGF-β). Additionally, the increased relative abundances of Lactobacillus spp. in SF piglets were positively correlated with growth rate, while the decreased abundances of Bilophila spp. were positively correlated with fecal lipocalin-2 levels. Our data reveal that a maternal SF diet during pregnancy has remarkable effects on an offspring's growth traits and intestinal permeability and inflammation, perhaps by modulating the composition and metabolism of gut microbiota.IMPORTANCE Although the direct effects of dietary soluble fiber on gut microbiota have been extensively studied, the more indirect effects of maternal nutrition solely during pregnancy on the development of the offspring's intestine are until now largely unexplored. Our data show that a maternal soluble fiber diet during pregnancy is independently associated with changes in the intestinal microbiota composition and metabolism of suckling piglets. These findings have direct implications for refining dietary recommendations in pregnancy. Moreover, a maternal soluble fiber diet reduces intestinal permeability and prevents intestinal inflammation and an excessive systemic immune response of suckling piglets. Therefore, the suckling piglets' resistance to disease was enhanced, diarrhea was reduced, and weight gain was raised. Additionally, the changes in gut microbiota in response to a maternal soluble fiber diet may also be directly correlated with the offspring's growth and gut development.

Vitamin A supplementation improves the intestinal mucosal barrier and facilitates the expression of tight junction proteins in rats with diarrhea

OBJECTIVES

The aim of this study is to investigate the specific effects of vitamin A (VA) on diarrhea in rats and its potential targets to protect the intestinal mucosa.

METHODS

Specific pathogen-free Sprague Dawley rats were fed a VA deficient (VAD) or VA normal (VAN) diet for 4 wk. Then, half of the VAN rats were treated with a VAN diet and the other half with a lactose VAN diet. VAD rats were randomly assigned to one of four groups and fed a VAD diet, lactose VAD diet, VAN diet with VA supplementation (VAS) via daily intragastric administration, or a lactose VAN diet with daily VAS. Rat weight and degree of diarrhea were evaluated daily. After 15 d, the serum retinol level was measured by high-performance liquid chromatography, and the serum diamine oxidase (DAO) and zonulin concentrations were analyzed by enzyme-linked immunosorbent assays. The small intestine mucosal pathology was observed by hematoxylin and eosin staining. Western blotting was performed to detect the protein expression levels of occludin and claudin-1 in the intestinal mucosa, and the zonula-occludens 1 expression was assessed using immunohistochemistry.

RESULTS

VAD limited weight gain in rats and increased the degree of diarrhea. The serum retinol levels and the level of tight junction (TJ) proteins claudin-1 and occludin and grip strength were affected by the interaction between lactose-induced diarrhea and the VA diet. Diarrhea, independent of VAD, significantly decreased rat weight, increased serum DAO levels, damaged small intestine villi, and impaired zonula-occludens 1 protein expression. VAD significantly increased the concentration of zonulin independently of diarrhea, but VAS increased the serum retinol level, reduced the severity of diarrhea, increased the expression levels of the TJ proteins, facilitated the restoration of the small intestine villi that were damaged by the diarrhea, and decreased the concentrations of serum DAO and zonulin.

CONCLUSIONS

VAD may aggravate the degree of diarrhea and intestinal mucosal damage during the duration of diarrhea, and VAS helps relieve diarrhea and improves intestinal damage likely by regulating the expression of TJ proteins. Therefore, VA plays a pivotal role in the protection of the intestinal mucosa during instances of diarrhea.

Early intervention with faecal microbiota transplantation: an effective means to improve growth performance and the intestinal development of suckling piglets

Recent studies indicate that early postnatal period is a critical window for gut microbiota manipulation to optimise the immunity and body growth. This study investigated the effects of maternal faecal microbiota orally administered to neonatal piglets after birth on growth performance, selected microbial populations, intestinal permeability and the development of intestinal mucosal immune system. In total, 12 litters of crossbred newborn piglets were selected in this study. Litter size was standardised to 10 piglets. On day 1, 10 piglets in each litter were randomly allotted to the faecal microbiota transplantation (FMT) and control groups. Piglets in the FMT group were orally administrated with 2ml faecal suspension of their nursing sow per day from the age of 1 to 3 days; piglets in the control group were treated with the same dose of a placebo (0.1M potassium phosphate buffer containing 10% glycerol (vol/vol)) inoculant. The experiment lasted 21 days. On days 7, 14 and 21, plasma and faecal samples were collected for the analysis of growth-related hormones and cytokines in plasma and lipocalin-2, secretory immunoglobulin A (sIgA), selected microbiota and short-chain fatty acids (SCFAs) in faeces. Faecal microbiota transplantation increased the average daily gain of piglets during week 3 and the whole experiment period. Compared with the control group, the FMT group had increased concentrations of plasma growth hormone and IGF-1 on days 14 and 21. Faecal microbiota transplantation also reduced the incidence of diarrhoea during weeks 1 and 3 and plasma concentrations of zonulin, endotoxin and diamine oxidase activities in piglets on days 7 and 14. The populations of Lactobacillus spp. and Faecalibacterium prausnitzii and the concentrations of faecal and plasma acetate, butyrate and total SCFAs in FMT group were higher than those in the control group on day 21. Moreover, the FMT piglets have higher concentrations of plasma transforming growth factor-β and immunoglobulin G, and faecal sIgA than the control piglets on day 21. These findings indicate that early intervention with maternal faecal microbiota improves growth performance, decreases intestinal permeability, stimulates sIgA secretion, and modulates gut microbiota composition and metabolism in suckling piglets.

Soya-saponins induce intestinal inflammation and barrier dysfunction in juvenile turbot (Scophthalmus maximus)

Soybean meal-induced enteritis (SBMIE) is a well-described condition in the distal intestine (DI) of several cultured fish species, but the exact cause is still unclear. The work on Atlantic salmon and zebrafish suggested soya-saponins, as heat-stable anti-nutritional factors in soybean meal, are the major causal agents. However, this conclusion was not supported by the research on some other fish, such as gilthead sea bream and European sea bass. Our previous work proved that soybean could induce SBMIE on turbot and the present work aimed to investigate whether soya-saponins alone could cause SBMIE and the effects of soya-saponins on the intestinal barrier function in juvenile turbot. Turbots with initial weight 11.4 ± 0.02 g were fed one of four fishmeal-based diets containing graded levels of soya-saponins (0, 2.5, 7.5, 15 g kg-1) for 8 weeks. At the end of the trial, all fish were weighed and plasma was obtained for diamine oxidase (DAO) activity and d-lactate level analysis and DI was sampled for histological evaluation and quantification of antioxidant parameters and inflammatory marker genes. The activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and intestinal glutathione level were selected to evaluated intestinal antioxidant system. The distal intestinal epithelial cell (IEC) proliferation and apoptosis were investigated by proliferating cell nuclear antigen (PCNA) labelling and TdT-mediated dUTP nick end labeling (TUNEL), respectively. The results showed that soya-saponins caused significantly dose-dependent decrease in the growth performance and nutrient utilization (p < 0.05). Enteritis developed in DI of the fish fed diet containing soya-saponins. Significantly dose-dependent increases in severity of the inflammation concomitant with up-regulated expression of il-1β, il-8, and tnf-α, increased IEC proliferation and apoptosis, and decreases in selected antioxidant parameters were detected (p < 0.05). The epithelial permeability (evaluated by the plasma DAO activity and d-lactate level) was significantly increased with the increasing of dietary level of soya-saponins (p < 0.05), which was concomitant with the destroyed the intracellular junctions. In conclusion, the present work proved that soya-saponins induced enteritis and compromised the intestinal barrier functions. Based on the present work, strategies focus on regulation of cell apoptosis, epithelial permeability, intracellular junctions and redox homeostasis worth further investigating to develop new and efficient ways for SBMIE alleviation.

Dietary supplementation with an amino acid blend enhances intestinal function in piglets

The traditionally classified nutritionally non-essential amino acids are now known to be insufficiently synthesized for maximal growth and optimal health in piglets. This study determined the effects of dietary supplementation with an amino acid blend (AAB; glutamate:glutamine:glycine:arginine:N-acetylcysteine = 5:2:2:1:0.5) on piglet growth performance and intestinal functions. Sixteen piglets (24-day-old) were randomly assigned to a corn and soybean meal-based diet supplemented with 0.99% alanine (isonitrogenous control) or 1% AAB. On day 20 of the trial, blood and intestinal tissue samples were obtained from piglets. Compared with the control, AAB supplementation reduced (P < 0.05) diarrhoea incidence; plasma alanine aminotransferase and diamine oxidase activities; intestinal concentrations of hydrogen peroxide, malondialdehyde, and heat shock protein-70, and intestinal mRNA levels for interleukin-1β, interferon-γ, and chemokine (C-X-C motif) ligand-9; and the numbers of Enterobacterium family, Enterococcus genus and Clostridium coccoides in the colon digesta. Furthermore, AAB supplementation enhanced (P < 0.05): the plasma concentrations of serine, aspartate, glutamate, cysteine, tyrosine, phenylalanine, tryptophan, lysine, arginine, citrulline, ornithine, taurine, and γ-aminobutyric acid; intestinal villus height and surface area, villus height/crypt depth ratio, antioxidative enzyme activities, and mRNA levels for porcine β-defensin-1, sodium-independent amino acid transporters (b^0,+AT and y⁺LAT1), aquaporin (AQP) 3, AQP8, AQP10, nuclear factor erythroid 2-related factor 2 and glutathione S-transferase omega-2, and protein abundances of AQP3, AQP4, claudin-1, occludin and myxovirus resistance 1; and the numbers of Bifidobacterium genus and Lactobacillus genus in the colon digesta. Collectively, these comprehensive results indicate that dietary AAB supplementation plays an important role in improving piglet growth and intestinal function.

N-Acetylcysteine supplementation alleviates intestinal injury in piglets infected by porcine epidemic diarrhea virus

Porcine epidemic diarrhea virus (PEDV) infects the intestine of young pigs, but effective measures for prevention and treatment are lacking. N-Acetylcysteine (NAC) has been shown to reduce endotoxin-induced intestinal dysfunction. This study was conducted with the PEDV-infected neonatal piglet model to determine the effect of NAC supplementation on intestinal function. Thirty-two 7-day-old piglets were randomly allocated to one of four treatments in a 2 × 2 factorial design consisting of two liquid diets (0 or 50 mg/kg BW NAC supplementation) and oral administration of 0 or 10^4.5 TCID₅₀ (50% tissue culture infectious dose) PEDV. On day 7 of the trial, half of the pigs (n = 8) in each dietary treatment received either sterile saline or PEDV (Yunnan province strain) solution at 10^4.5 TCID₅₀ per pig. On day 10 of the trial, D-xylose (0.1 g/kg BW) was orally administrated to all pigs. One hour later, jugular vein blood samples were collected, and then all pigs were killed to obtain the small intestine. PEDV infection increased diarrhea incidence, while reducing ADG. PEDV infection also decreased plasma D-xylose concentration, small intestinal villus height, mucosal I-FABP and villin mRNA levels but increased mucosal MX1 and GCNT3 mRNA levels (P < 0.05). Dietary NAC supplementation ameliorated the PEDV-induced abnormal changes in all the measured variables. Moreover, NAC reduced oxidative stress, as indicated by decreases in plasma and mucosal H₂O₂ levels. Collectively, these novel results indicate that dietary supplementation with NAC alleviates intestinal mucosal damage and improves the absorptive function of the small intestine in PEDV-infected piglets.

The Dipeptide Alanyl-Glutamine Prevents Intestinal Mucosal Atrophy in Parenterally Fed Rats

This study was performed to determine whether the addition of alanyl-glutamine (Ala-Gln) can prevent intestinal mucosal atrophy induced by standard solution of total parenteral nutrition (S-TPN). Forty-one male Sprague-Dawley rats weighing 250 g were randomly divided into four groups: group I was killed after overnight fasting; group II received S-TPN. The other groups received S-TPN supplemented with amino acids other than glutamine (group III) or supplemented with Ala-Gln 2 g/100 mL (group IV); both solutions were isocaloric and isonitrogenous. After 1 week of TPN the rats were killed, and the duodenum, proximal jejunum, mid-small bowel, and distal ileum were obtained for morphologic and functional analysis. Weight gain did not differ significantly among these four groups, and there was no difference in nitrogen balance between groups III and IV. Serum glutamine in group IV (102.8 +/- 13.3 mumol/dL) was significantly increased (p less than .05) compared with groups I, II, and III (66.2 +/- 3.9, 55.7 +/- 7.8, and 61.3 +/- 10.8 mumol/dL, respectively). Mucosal wet weight, protein, RNA, sucrase, and maltase of group IV were significantly increased (p less than .05) compared with groups II and III. Villus height was significantly increased (p less than .05) in the jejunum of group IV rats compared with groups II and III, but not in any other segments of the intestine. No significant changes were observed in crypt depth among all groups. Diamine oxidase in groups II, III, and IV was significantly decreased (p less than .05) compared with group I in all segments except for the ileum.(ABSTRACT TRUNCATED AT 250 WORDS)

Impaired function of the intestinal barrier in a novel sub-health rat model

Sub-health is a state featuring a deterioration in physiological function between health and illness, and the sub-health condition has surfaced as life-threatening in humans. The aim of the present study was to establish a sub-health model in rats, and investigate the function of the intestinal barrier in the sub-health rats and rats following intervention. To establish a sub‑health model, the rats were subjected to a high‑fat and sugar diet, motion restriction and chronic stress. Their serum glucose and triglyceride levels, immune function and adaptability were then measured. The levels of diamine oxidase and D‑lactic acid in the plasma were analyzed as markers of the intestinal permeability. The protein and mRNA expression levels of anti‑apoptotic YWHAZ in the colonic tissue was detected using immunohistochemical and reverse transcription‑quantitative polymerase chain reaction analyses In the present study, the sub‑health rat model was successfully established, and sub‑health factors increased the intestinal permeability and reduced the expression of YWHAZ. Providing sub‑health rats with normal living conditions did not improve the function of the intestinal barrier. In conclusion, the results of the present study demonstrated that intestinal disorders in the sub‑health rat model may result from the damage caused by reduce intestinal barrier function as well as the decreased expression levels of YWHAZ. Additionally, rats in the sub‑health condition did not recover following subsequent exposure to normal living conditions, suggesting that certain exercises or medical intervention may be necessary to improve sub-health symptoms.

Serum diamine oxidase activity as a predictor of gastrointestinal toxicity and malnutrition due to anticancer drugs

BACKGROUND AND AIM

Objective evaluation of intestinal mucosal damage due to anticancer drugs is generally difficult. Serum diamine oxidase (DAO) activity is reported to reflect the integrity and maturity of the small intestinal mucosa. Therefore, we investigated whether serum DAO activity is an indicator of gastrointestinal toxicity or nutritional status in patients receiving chemotherapy.

METHODS

We prospectively enrolled 20 patients with unresectable metastatic gastric cancer who received oral S-1 (80 mg/m(2) ) on days 1-14, and intravenous cisplatin (60 mg/m(2) ) and docetaxel (50 mg/m(2) ) on day 8 every 3 weeks. Serum DAO activity was measured by colorimetry. Gastrointestinal toxicity was evaluated by Common Toxicity Criteria for Adverse Events version 4.0. Endoscopic examination and biopsy of duodenal mucosa assessed mucosal damage. Malnutrition was evaluated by measuring serum total protein and albumin levels.

RESULTS

Serum DAO activity decreased step-by-step significantly during anticancer drug treatment and recovered after drug holidays. In all 14 patients who experienced diarrhea, serum DAO activity significantly decreased prior to diarrhea onset. Percent decrease in DAO activity was significantly correlated with severity of diarrhea. Significant correlation was observed between percent decrease in DAO activity and percent decrease in duodenal villus height or surface area from baseline. There were also significant correlations between percent decrease in serum DAO activity at day 14 and percent decrease in serum total protein or albumin levels at day 21 from baseline.

CONCLUSION

Serum DAO activity sensitively indicates gastrointestinal damage prior to symptom onset and can be a useful predictor of intestinal mucosal damage and nutritional status in patients receiving chemotherapy.

Effect of bile pigments on the compromised gut barrier function in a rat model of bile duct ligation

Background

Studies have shown that the absence of bile in the gut lumen, either by bile duct ligation or bile diversion, induces mucosal injury. However, the mechanism remains elusive. In this study, the role of bile pigments in gut barrier function was investigated in a rat model of bile duct ligation.

Methods

Male Sprague Dawley (SD) rats were used in this study. After ligation of bile duct, the animals were administrated with free bilirubin, bilirubin ditaurate, or biliverdin by intragastric gavage. 1, 2, or 3 days later, the animals were sacrificed and the damage of mucosa was assessed by histological staining as well as biochemical parameters such as changes of diamine oxidase (DAO) and D-lactate (D-Lac) in the blood. Trypsin and chymotrypsin of the gut were also measured to determine how these digestive proteases may relate to the observed effects of bile pigments.

Results

Bile duct ligation (BDL) caused significant increases in gut trypsin and chymotrypsin along with damage of the mucosa as demonstrated by the histological findings under microscope, the reduced expression of tight junction molecules like occludin, and significant changes in DAO and D-lac in the blood. Free bilirubin but not bilirubin ditaurate or biliverdin showed significant inhibitions on trypsin and chymotrypsin as well as alleviated changes of histological and biochemical parameters related to gut barrier disruption.

Conclusion

Bile may protect the gut from damage through inhibiting digestive proteases like trypsin and chymotrypsin by free bilirubin.

Diamine oxidase activity levels in anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) patients often experience gastrointestinal complications caused by their malnutrition. We hypothesized that intestinal integrity is disturbed in AN. Therefore, the objective of the present study was to investigate serum diamine oxidase (DAO) activity, which is considered to be a clinical indicator of the integrity of the intestinal mucosa, in AN patients.

METHOD

Thirty-six AN female patients including 21 AN restricting type (AN-R) and 15 AN binge-eating/purging type (AN-BP) were compared with twenty healthy women on serum DAO activity using immunoassay.

RESULTS

DAO levels in AN-R patients were significantly lower than in AN-BP patients and healthy controls.

DISCUSSION

DAO levels were decreased in AN-R patients. This finding suggests the presence of intestinal structural disturbance as one of the physical complications of malnutrition in AN-R patients.

Dietary supplementation with tributyrin alleviates intestinal injury in piglets challenged with intrarectal administration of acetic acid

Tributyrin (TBU) is a good dietary source of butyrate and has beneficial effects on the maintenance of normal intestinal morphology. The present study tested the hypothesis that dietary TBU supplementation could alleviate intestinal injury in the acetic acid (ACA)-induced porcine model of colitis. A total of eighteen piglets (25 d old) were randomly allocated to one of three treatment groups (control, ACA and TBU). The control and ACA groups were fed a basal diet and the TBU group was fed the basal diet supplemented with 0·1 % TBU. On day 15 of the trial, under anaesthesia, a soft catheter was inserted into the rectum of piglets (20-25 cm from the anus), followed by administration of either saline (control group) or ACA (10 ml of 10 % ACA solution for ACA and TBU groups). On day 22 of the trial, after venous blood samples were collected, piglets were killed to obtain mid-ileum and mid-colon mucosae. Compared with the control group, the ACA group exhibited an increase (P< 0·05) in lymphocyte counts, creatinine, PGE2, and malondialdehyde concentrations and diamine oxidase and inducible NO synthase activities in the plasma and lymphocyte density in the colon and a decrease in insulin concentrations and glutathione peroxidase activity, ileal villus height:crypt depth ratios and goblet cell numbers in the colon. These adverse effects of ACA were attenuated by TBU supplementation. Moreover, TBU prevented the ACA-induced increase in caspase-3 levels while enhancing claudin-1 protein and epidermal growth factor receptor (EGFR) mRNA expression in the colonic mucosa. Collectively, these results indicate that dietary supplementation with 0·1 % TBU alleviates ACA-induced intestinal injury possibly by inhibiting apoptosis, promoting tight-junction formation and activating EGFR signalling.

Whey Peptide-Based Formulas With ω-3 Fatty Acids Are Protective in Lipopolysaccharide-Mediated Sepsis

BACKGROUND

Sepsis and septic shock syndrome are among the leading causes of death in critically ill patients. Lipopolysaccharide (LPS) released by bacteria within the colon may translocate across a compromised epithelium, leading to oxidative stress, inflammation, sepsis, and eventually death.

METHODS

We examined the effects of a whey-based enteral formula high in cysteine (antioxidant precursor) and the addition of ω-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), against a mouse model of LPS-induced sepsis. Mice were fed either a whey-based diet with EPA-DHA (PAF), a whey-based diet without EPA-DHA (PSTD), or a casein-based control diet (CONT).

RESULTS

Mice fed PAF or PSTD were protected against LPS-induced weight loss. Whey-based diets suppressed inflammatory cytokine release and oxidative stress damage. Furthermore, PAF and PSTD were able to inhibit autophagy, a mechanism in which the cell recycles damaged organelles. These anti-inflammatory and antioxidative effects of PSTD and PAF resulted in decreased liver inflammation and intestinal damage and promoted protective microbiota within the intestines.

CONCLUSIONS

These data suggest a clinical role for whey peptide-based diets in promoting healing and recovery in critically ill patients.

Blocking abdominal lymphatic flow attenuates acute hemorrhagic necrotizing pancreatitis -associated lung injury in rats

BACKGROUND

Acute hemorrhagic necrotizing pancreatitis (AHNP) is a severe acute inflammatory of pancreas that can lead to extrapancreatic organ disfunction. The lung and intestine is the most common involved organs, and abdominal lymphatic flow may contribute to AHNP- associated organ injury. In this study, we investigated the impact of thoracic duct ligation and drainage on lung and intestine injury in rats with AHNP.

METHODS

Thirty-two male Wistar rats were randomly divided into 4 groups: sham operation group, AHNP group, AHNP + ligation group and AHNP + drainage group. Rat AHNP model was induced by retrograde injection of 3.5% sodium deoxycholate into the biliopancreatic duct, and the sham operation group was injected only with saline. In AHNP + ligation group and AHNP + drainage group, thoracic duct was ligated or drainaged before model induction. At 6 h after model induction, the bronchoalveolar lavage fluid (BALF) were collected for determination of tumor necrosis factor-alpha (TNF-alpha), and the tissues of lung, intestine and pancrease were harvested individually for pathohistological evaluation and the myeloperoxidase (MPO) activity determination. In addition, the activity of serum amylase and diamine oxidase (DAO) was determined in each group.

RESULTS

The pathohistological damage and MPO of lung, intestine and pancrease, TNF-alpha of BALF, serum amylase and DAO were all increased in AHNP group compared to those in sham operation group (P < 0.05). In AHNP + ligation group, the pathohistological damage and MPO of lung and TNF-alpha of BALF were reduced, but the pathohistological damage and MPO of intestine and pancrease were increased compared with AHNP group (P < 0.05), however the activity of serum amylase and DAO was no changed. In AHNP + drainage group, the pathohistological damage and MPO of lung, intestine and pancrease, TNF-alpha of BALF, serum amylase and DAO were all reduced compared to those in AHNP group (P < 0.05).

CONCLUSIONS

Our finding suggest that thoracic duct ligation can reduce neutrophil infiltration and TNF-alpha release and then attenuates lung injury in rats with AHNP, but aggravates the injury of intestine and pancrease. While thoracic duct drainage attenuates the injury of lung, intestine and pancreaseat the same time in rats with AHNP.

Combined early fluid resuscitation and hydrogen inhalation attenuates lung and intestine injury

AIM: To study the effects of combined early fluid resuscitation and hydrogen inhalation on septic shock-induced lung and intestine injuries.

METHODS: Wistar male rats were randomly divided into four groups: control group (Group A, n = 15); septic shock group (Group B, n = 15); early fluid resuscitation-treated septic shock group (Group C, n = 15); and early fluid resuscitation and inhalation of 2% hydrogen-treated septic shock group (Group D, n = 15). The activity of hydroxyl radicals, myeloperoxidase (MPO), superoxide dismutase (SOD), diamine oxidase (DAO), and the concentration of malonaldehyde (MDA) in the lung and intestinal tissue were assessed according to the corresponding kits. Hematoxylin and eosin staining was carried out to detect the pathology of the lung and intestine. The expression levels of interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α in lung and intestine tissue were detected by enzyme-linked immunosorbent assay method. The expression levels of Fas and Bcl2 in lung tissues were determined by immunohistochemistry and Western blotting.

RESULTS: Septic shock elicited a significant increase in the levels of MDA (10.17 ± 1.12 nmol/mg protein vs 2.98 ± 0.64 nmol/mg protein) and MPO (6.79 ± 1.02 U/g wet tissue vs 1.69 ± 0.14 U/g wet tissue) in lung tissues. These effects were not significantly decreased by Group C pretreatment, but were significantly reduced by Group D pretreatment (MDA: 4.45 ± 1.13 nmol/mg protein vs 9.56 ± 1.37 nmol/mg protein; MPO: 2.58 ± 0.21 U/g wet tissue vs 6.02 ± 1.16 U/g wet tissue). The activity of SOD (250.32 ± 8.56 U/mg protein vs 365.78 ± 10.26 U/mg protein) in lung tissues was decreased after septic shock, and was not significantly increased by Group C pretreatment, but was significantly enhanced by Group D pretreatment (331.15 ± 9.64 U/mg protein vs 262.98 ± 5.47 U/mg protein). Histological evidence of lung hemorrhage, neutrophil infiltration and overexpression of IL-6, IL-8, and TNF-α was observed in lung tissues, all of which were attenuated by Group C and further alleviated by Group D pretreatment. Septic shock also elicited a significant increase in the levels of MDA, MPO and DAO (6.54 ± 0.68 kU/L vs 4.32 ± 0.33 kU/L) in intestinal tissues, all of which were further increased by Group C, but significantly reduced by Group D pretreatment. Increased Chiu scoring and overexpression of IL-6, IL-8 and TNF-α were observed in intestinal tissues, all of which were attenuated by Group C and further attenuated by Group D pretreatment.

CONCLUSION: Combined early fluid resuscitation and hydrogen inhalation may protect the lung and intestine of the septic shock rats from the damage induced by oxidative stress and the inflammatory reaction.

Glucagonlike peptide 2 protects intestinal barrier in severe acute pancreatitis through regulating intestinal epithelial cell proliferation and apoptosis

OBJECTIVE

To investigate the protective effect of glucagon-like peptide 2 (GLP-2) on intestinal barrier dysfunction in severe acute pancreatitis and to explore the putative mechanism of this effect.

METHODS

Thirty rats were randomly divided into 3 groups. Group 1 received sham operation. Severe acute pancreatitis was induced in group 2 and group 3 via retrograde injection of 3% sodium taurocholate to the pancreatic duct. Rats in group 3 were peritoneally injected with GLP-2. Intestinal barrier dysfunction was characterized by the histological measurements and concentration of plasma diamine oxidase. The tissue sections of ileum were collected for the detection of proliferating cell nuclear antigen protein and apoptosis.

RESULTS

Glucagon-like peptide 2 administration improved the ileal mucosal injury, which was also demonstrated by the histological score of ileal mucosa. The concentration of diamine oxidase was decreased in rats with acute pancreatitis treated with GLP-2. Acute pancreatitis-induced epithelial cell apoptosis was partly prevented by GLP-2. Immunohistochemical staining of proliferating cell nuclear antigen protein was increased in group 3 compared with that in group 2.

CONCLUSIONS

Results from this study suggest that GLP-2 has a protective effect on intestinal barrier dysfunction in rats with severe acute pancreatitis via mechanisms closely involving promotion of cell growth and inhibition of intestinal epithelial cell apoptosis.

Plasma diamine oxidase activity is a useful biomarker for evaluating gastrointestinal tract toxicities during chemotherapy with oral fluorouracil anti-cancer drugs in patients with gastric cancer

OBJECTIVES

Diamine oxidase (DAO) is an enzyme that catalyzes oxidation and is highly active in the mature upper villus cells of the intestinal mucosa. This study sought to evaluate plasma DAO activities during adjuvant chemotherapy in patients with gastric cancer.

METHODS

We investigated 20 patients with gastric cancer who were treated with oral fluorouracil anti-cancer drugs as adjuvant chemotherapy. Plasma DAO activity was measured in all patients before chemotherapy and at 2, 4 and 6 weeks after the start of chemotherapy, and quality of life was evaluated simultaneously.

RESULTS

The median DAO activity after 4 weeks of chemotherapy was significantly decreased compared to the pre-chemotherapy levels (6.6 vs. 7.5 U/l; p = 0.038). The changes in the rate of DAO activity at 2 and 6 weeks following the start of chemotherapy in patients with gastrointestinal tract toxicity were significantly lower than in those without toxicity (p =0.021 and 0.047, respectively). The patient cohort showed a slightly positive correlation between DAO activity and global health status and a negative correlation between DAO activity and appetite loss.

CONCLUSIONS

Plasma DAO activities may be useful for monitoring and evaluating gastrointestinal tract toxicities induced by adjuvant chemotherapy with oral fluorouracil in patients with gastric cancer.

Protective effects of N-acetylcysteine on intestinal functions of piglets challenged with lipopolysaccharide

The neonatal small intestine is susceptible to damage by endotoxin, but effective methods for prevention and treatment are lacking. N-acetylcysteine (NAC) is a widely used precursor of L: -cysteine for animal cells and plays an important role in protecting cells against oxidative stress. This study was conducted with the lipopolysaccharide (LPS)-challenged piglet model to determine the effects of NAC on intestinal function. Eighteen piglets were randomly allocated into control, LPS and LPS + NAC groups. The control and LPS groups were fed a corn- and soybean meal-based diet, and the LPS + NAC group was fed the basal diet +500 mg/kg NAC. On days 10, 13 and 20 of the trial, the LPS and LPS + NAC groups received intraperitoneal administration of LPS (100 μg/kg BW), whereas the control piglets received saline. On day 20 of the trial, D-: xylose (0.1 g/kg BW) was orally administrated to all piglets 2 h after LPS or saline injection, and blood samples were collected 1 h thereafter. One hour blood xylose test was used to measure intestinal absorption capacity and mucosal integrity, and diamine oxidase (DAO) was used as a marker of intestinal injury. On day 21 of the trial, pigs were killed to obtain the intestinal mucosa. Compared to the control, LPS challenge reduced (P < 0.05) the concentrations of D-: xylose (a marker of intestinal absorption) in plasma, activities of DAO in the jejunal mucosa, the ratio of villus height to crypt depth in the jejunal mucosa, RNA/DNA and protein/DNA in the jejunal and ileal mucosae, while increasing (P < 0.05) DAO activity in plasma and caspase-3 expression in the intestinal mucosa. The adverse effects of LPS were partially ameliorated (P < 0.05) by NAC supplementation. Moreover, NAC prevented the LPS-induced decrease in claudin-1 and occludin expression in the jejunal and ileal mucosae. Collectively, these results indicate that dietary NAC supplementation alleviates the mucosal damage and improves the absorptive function of the small intestine in LPS-challenged piglets.

Over-starvation aggravates intestinal injury and promotes bacterial and endotoxin translocation under high-altitude hypoxic environment

AIM: To study whether over-starvation aggravates intestinal mucosal injury and promotes bacterial and endotoxin translocation in a high-altitude hypoxic environment.

METHODS: Sprague-Dawley rats were exposed to hypobaric hypoxia at a simulated altitude of 7000 m for 72 h. Lanthanum nitrate was used as a tracer to detect intestinal injury. Epithelial apoptosis was observed with terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Serum levels of diamino oxidase (DAO), malondialdehyde (MDA), glutamine (Gln), superoxide dismutase (SOD) and endotoxin were measured in intestinal mucosa. Bacterial translocation was detected in blood culture and intestinal homogenates. In addition, rats were given Gln intragastrically to observe its protective effect on intestinal injury.

RESULTS: Apoptotic epithelial cells, exfoliated villi and inflammatory cells in intestine were increased with edema in the lamina propria accompanying effusion of red blood cells. Lanthanum particles were found in the intercellular space and intracellular compartment. Bacterial translocation to mesenteric lymph nodes (MLN) and spleen was evident. The serum endotoxin, DAO and MDA levels were significantly higher while the serum SOD, DAO and Gln levels were lower in intestine (P < 0.05). The bacterial translocation number was lower in the high altitude hypoxic group than in the high altitude starvation group (0.47 ± 0.83 vs 2.38 ± 1.45, P < 0.05). The bacterial translocation was found in each organ, especially in MLN and spleen but not in peripheral blood. The bacterial and endotoxin translocations were both markedly improved in rats after treatment with Gln.

CONCLUSION: High-altitude hypoxia and starvation cause severe intestinal mucosal injury and increase bacterial and endotoxin translocation, which can be treated with Gln.

Curcumin protects intestinal mucosal barrier function of rat enteritis via activation of MKP-1 and attenuation of p38 and NF-κB activation

Background

Intestinal mucosa barrier (IMB) dysfunction results in many notorious diseases for which there are currently few effective treatments. We studied curcumin's protective effect on IMB and examined its mechanism by using methotrexate (MTX) induced rat enteritis model and lipopolysaccharide (LPS) treated cell death model.

Methodology/Principal Findings

Curcumin was intragastrically administrated from the first day, models were made for 7 days. Cells were treated with curcumin for 30 min before exposure to LPS. Rat intestinal mucosa was collected for evaluation of pathological changes. We detected the activities of D-lactate and diamine oxidase (DAO) according to previous research and measured the levels of myeloperoxidase (MPO) and superoxide dismutase (SOD) by colorimetric method. Intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were determined by RT-PCR and IL-10 production was determined by ELISA. We found Curcumin decreased the levels of D-lactate, DAO, MPO, ICAM-1, IL-1β and TNF-α, but increased the levels of IL-10 and SOD in rat models. We further confirmed mitogen-activated protein kinase phosphatase-1 (MKP-1) was activated but phospho-p38 was inhibited by curcumin by western blot assay. Finally, NF-κB translocation was monitored by immunofluorescent staining. We showed that curcumin repressed I-κB and interfered with the translocation of NF-κB into nucleus.

Conclusions/Significance

The effect of curcumin is mediated by the MKP-1-dependent inactivation of p38 and inhibition of NF-κB-mediated transcription. Curcumin, with anti-inflammatory and anti-oxidant activities may be used as an effective reagent for protecting intestinal mucosa barrier and other related intestinal diseases.

Soluble intercellular adhesion molecule-1, D-lactate and diamine oxidase in patients with inflammatory bowel disease

AIM: To study the levels of serum soluble intercellular adhesion molecule-1 (sICAM-1), plasma D-lactate and diamine oxidase (DAO) in patients with inflammatory bowel disease (IBD), and the potential clinical significance.

METHODS: Sixty-nine patients with IBD and 30 healthy controls were included in this study. The concentration of sICAM-1 was detected with enzyme-linked immunosorbent assay, the level of D-lactate and DAO was measured by spectroscopic analysis, and the number of white blood cells (WBC) was determined by routine procedure.

RESULTS: The levels of sICAM-l, DAO, and WBC in IBD patients were significantly higher than those in the control group (P < 0.01). sICAM-l in IBD patients was found to be closely related to the levels of DAO and D-lactate (212.94 ± 69.89 vs 6.35 ± 2.35, P = 0.000), DAO 212.94 ± 69.89 vs 8.65 ± 3.54, P = 0.000) and WBC (212.94 ± 69.89 vs 7.40 ± 2.61, P = 0.000), but no significant difference was observed between patients with ulcerative colitis and patients with Crohn’s disease. The post-treatment levels of sICAM-l, D-lactate and WBC were significantly lower than before treatment (sICAM-l 206.57 ± 79.21 vs 146.21 ± 64.43, P = 0.000), (D-lactate 1.46 ± 0.94 vs 0.52 ± 0.32, P = 0.000) and (WBC 7.24 ± 0.2.33 vs 5.21 ± 3.21, P = 0.000).

CONCLUSION: sICAM-1, D-lactate and DAO are closely related to the specific conditions of IBD, and thus could be used as a major diagnostic index.

Hydrogen-rich saline protects against intestinal ischemia/reperfusion injury in rats

Hydrogen gas was reported to reduce reactive oxygen species and alleviate cerebral, myocardial and hepatic ischemia/reperfusion (I/R) injuries. This paper studied the effect of hydrogen-rich saline, which was easier for clinical application, on the intestinal I/R injury. Model of intestinal I/R injury was induced in male Sprague-Dawley rats. Physiological saline, hydrogen-rich saline or nitrogen-rich saline (5 ml/kg) was administered via intravenous infusion at 10 min before reperfusion, respectively. The intestine damage was detected microscopically and was assessed by Chiu score system after I/R injury. In addition, serum DAO activity, TNF-alpha, IL-1beta and IL-6 levels, tissue MDA, protein carbonyl and MPO activity were all increased significantly by I/R injury. Hydrogen-rich saline reduced these markers and relieved morphological intestinal injury, while no significant reduction was observed in the nitrogen-rich saline-treated animals. In conclusion, hydrogen-rich saline protected the small intestine against I/R injury, possibly by reduction of inflammation and oxidative stress.

RECOMBINANT BACTERICIDAL/PERMEABILITY-INCREASING PROTEIN INHIBITS ENDOTOXIN-INDUCED HIGH-MOBILITY GROUP BOX 1 PROTEIN GENE EXPRESSION IN SEPSIS

We investigated in vivo the effect of recombinant bactericidal/permeability-increasing protein (rBPI21) on high-mobility group box 1 protein (HMGB1) expression in sepsis and its potential mechanism. Using a sepsis model induced by cecal ligation and puncture (CLP), rats were randomly divided into four groups as follows: normal control group, sham-operated group, CLP group, and BPI treatment group. Animals were killed at designated time points, and blood and tissue samples from liver, lungs, kidneys, and small intestine were harvested to determine related variables. In addition, we observed the effect of treatment with rBPI21 on survival rate in septic rats. The results showed that endotoxin content and expression levels of HMGB1 and LPS binding protein/CD14 mRNA in various organs were significantly increased at 12 and 24 h after CLP, which can be attenuated by treatment with rBPI21 (P<0.05-0.01). Meanwhile, treatment with rBPI21 in septic rats can markedly reduce serum alanine aminotransferase, creatinine levels, and pulmonary myeloperoxidase activity at 12 and 24 h after CLP, increase diamine oxidase activity at both time points (P<0.05-0.01), and improve the 1- to 10-day survival rates in animals subjected to CLP (P=0.012). These findings suggest that treatment with rBPI21 can significantly reduce endotoxin contents and expression levels of HMGB1 and LPS binding protein/CD14 mRNA in various organs in sepsis induced by CLP, and can protect against multiple organ damage resulting from sepsis. The effect of rBPI21 inhibiting HMGB1 gene expression in sepsis might be associated with endotoxin-dependent mechanisms.

Sodium butyrate prevents lethality of severe sepsis in rats

This study was performed to investigate a novel strategy to pharmacologically inhibit high-mobility group box 1 protein (HMGB1) expression with sodium butyrate, a short-chain fatty acid. Using a sepsis model induced by cecal ligation and puncture (CLP), 100 male Wistar rats were randomly divided into 4 groups as follows: control group (10 rats), sham operation group (10 rats), CLP group (further randomized into 2, 6, 12, 24, 48, and 72 h post-CLP subgroups, each 10 rats), and sodium butyrate treatment group (further randomized into 12 and 24 h post-CLP subgroups, each 10 rats). Animals of all groups were killed at designated time points, and blood and tissue samples from livers, lungs, kidneys, and small intestines were harvested to determine organ damage-related variables, and HMGB1 mRNA expression was assessed by the reverse-transcription-polymerase chain reaction. In addition, we observed the effect of treatment with sodium butyrate on survival rate in septic rats. The results showed that early treatment with sodium butyrate can markedly reduce serum alanine aminotransferase, creatinine levels at 12 h, and pulmonary myeloperoxidase activity at 24 h post-CLP, and significantly improve the 1- to 6-day survival rates in animals subjected to CLP (P < 0.05-0.01). These findings suggest that HMGB1 is excessively expressed and produced in sepsis. Sodium butyrate can markedly inhibit HMGB1 mRNA expression and may have protective effect on multiple organ damage in sepsis.

Synbiotics reduce postoperative infectious complications: a randomized controlled trial in biliary cancer patients undergoing hepatectomy

BACKGROUND AND AIMS

The clinical value of synbiotics in surgical patients remains unclear. The aim of this study was to investigate the effect of synbiotics on intestinal integrity and microflora, as well as on surgical outcome, in patients undergoing high-risk hepatectomy.

METHODS

Fifty-four patients with biliary cancer were randomly allocated to two groups before hepatectomy. One group received postoperative enteral feeding that included synbiotics; the other received enteral feeding only. Lactulose/mannitol (L/M) ratio, serum diamine oxidase (DAO) activity, and fecal microflora and organic acid concentrations were determined. Postoperative infectious complications were recorded.

RESULTS

Of the 54 patients, 44 completed the trial (21 receiving synbiotics and 23 others as controls). Postoperative changes in L/M ratios and serum DAO activities were identical between the two groups. Numbers of beneficial bacteria increased in the synbiotics group after surgery but decreased in controls. Numbers of harmful microorganisms decreased in the synbiotics group but increased in controls. Total organic acid concentrations increased in the synbiotics group but decreased in controls. Incidence of infectious complications was 19% (4/21) in the synbiotics group and 52% (12/23) in controls (P<0.05). All study patients tolerated surgery (mortality 0%).

CONCLUSIONS

Synbiotics, combined with early enteral nutrition, can reduce postoperative infections. This beneficial effect presumably involves correction of an intestinal microbial imbalance induced by surgical stress.