Mechanism of cytokine modulation of epithelial tight junction barrier

Elucidating the modulatory role of dietary hydroxyproline on the integrity and functional performance of the intestinal barrier in early-weaned piglets: A comprehensive analysis of its interplay with the gut microbiota and metabolites

Piglets receive far less hydroxyproline (Hyp) from a diet after weaning than they obtained from sow's milk prior to weaning, suggesting that Hyp may play a protective role in preserving intestinal mucosal homeostasis. This study aimed to evaluate the effect of Hyp on intestinal barrier function and its associated gut microbiota and metabolites in early-weaned piglets. Eighty weaned piglets were divided into four groups and fed diets containing different Hyp levels (0 %, 0.5 %, 1 %, or 2 %) for 21 days. Samples, including intestinal contents, tissues, and blood, were collected on day 7 for analysis of microbial composition, intestinal barrier function, and metabolites. We demonstrated that dietary supplementation with 2 % Hyp improved the feed conversion ratio and reduced the incidence of diarrhea in early-weaned piglets compared to the control group. Concurrently, Hyp enhanced intestinal barrier function by facilitating tight junction protein (zonula occludens (ZO)-1 and occludin) expression and mucin production in the jejunal, ileal, and colonic mucosas. It also improved mucosal immunity (by increasing the amount of secretory IgA (sIgA) and the ratio of CD4+/CD8+ T lymphocytes and decreasing NF-κB phosphorylation) and increased antioxidant capacity (by raising total antioxidant capacity (T-AOC) and glutathione levels) in the intestinal mucosa. In addition, Hyp supplementation resulted in an increase in the levels of glycine, glutathione, and glycine-conjugated bile acids, while decreasing the concentrations of cortisol and methionine sulfoxide in plasma. Intriguingly, piglets fed diet containing Hyp exhibited a remarkable increase in the abundance of probiotic Enterococcus faecium within their colonic contents. This elevation occurred alongside an attenuation of pro-inflammatory responses and an enhancement in intestinal barrier integrity. Further, these changes were accompanied by a rise in anti-inflammatory metabolites, specifically glycochenodeoxycholic acid and guanosine, along with a suppression of pro-inflammatory lipid peroxidation products, including (12Z)-9,10-dihydroxyoctadec-12-enoic acid (9,10-DHOME) and 13-L-hydroperoxylinoleic acid (13(S)-HPODE). In summary, Hyp holds the capacity to enhance the intestinal barrier function in weaned piglets; this effect is correlated with changes in the gut microbiota and metabolites. Our findings provide novel insights into the role of Hyp in maintaining gut homeostasis, highlighting its potential as a dietary supplement for promoting intestinal health in early-weaned piglets.

Cadmium modulates intestinal Wnt/β-catenin signaling ensuing intestinal barrier disruption and systemic inflammation

The intricate architecture of the intestinal epithelium, crucial for nutrient absorption, is constantly threatened by environmental factors. The epithelium undergoes rapid turnover, which is essential for maintaining homeostasis, under the control of intestinal stem cells (ISCs). The central regulator, Wnt/β-catenin signaling plays a key role in intestinal integrity and turnover. Despite its significance, the impact of environmental factors on this pathway has been largely overlooked. This study, for the first time, investigates the influence of Cd on the intestinal Wnt signaling pathway using a mouse model. In this study, male BALB/c mice were administered an environmentally relevant Cd dose (0.98 mg/kg) through oral gavage to investigate the intestinal disruption and Wnt signaling pathway. Various studies, including histopathology, immunohistochemistry, RT-PCR, western blotting, ELISA, intestinal permeability assay, and flow cytometry, were conducted to study Cd-induced changes in the intestine. The canonical Wnt signaling pathway experienced significant downregulation as a result of sub-chronic Cd exposure, which caused extensive damage throughout the small intestine. Increased intestinal permeability and a skewed immune response were also observed. To confirm that Wnt signaling downregulation is the key driver of Cd-induced gastrointestinal toxicity, mice were co-exposed to LiCl (a recognized Wnt activator) and Cd. The results clearly showed that the harmful effects of Cd could be reversed, which is strong evidence that Cd mostly damages the intestine through the Wnt/β-catenin signalling axis. In conclusion, this research advances the current understanding of the role of Wnt/β catenin signaling in gastrointestinal toxicity caused by diverse environmental pollutants.

Dietary nutrition, intestinal microbiota dysbiosis and post-weaning diarrhea in piglets

Weaning is a critical transitional point in the life cycle of piglets. Early weaning can lead to post-weaning syndrome, destroy the intestinal barrier function and microbiota homeostasis, cause diarrhea and threaten the health of piglets. The nutritional components of milk and solid foods consumed by newborn animals can affect the diversity and structure of their intestinal microbiota, and regulate post-weaning diarrhea in piglets. Therefore, this paper reviews the effects and mechanisms of different nutrients, including protein, dietary fiber, dietary fatty acids and dietary electrolyte balance, on diarrhea and health of piglets by regulating intestinal function. Protein is an essential nutrient for the growth of piglets; however, excessive intake will cause many harmful effects, such as allergic reactions, intestinal barrier dysfunction and pathogenic growth, eventually aggravating piglet diarrhea. Dietary fiber is a nutrient that alleviates post-weaning diarrhea in piglets, which is related to its promotion of intestinal epithelial integrity, microbial homeostasis and the production of short-chain fatty acids. In addition, dietary fatty acids and dietary electrolyte balance can also facilitate the growth, function and health of piglets by regulating intestinal epithelial function, immune system and microbiota. Thus, a targeted control of dietary components to promote the establishment of a healthy bacterial community is a significant method for preventing nutritional diarrhea in weaned piglets.

L-Glutamine Substantially Improves 5-Fluorouracil-Induced Intestinal Mucositis by Modulating Gut Microbiota and Maintaining the Integrity of the Gut Barrier in Mice

SCOPE

This study investigates the potential of glutamine to mitigate intestinal mucositis and dysbiosis caused by the chemotherapeutic agent 5-fluorouracil (5-FU).

METHODS AND RESULTS

Over twelve days, Institute of Cancer Research (ICR) mice are given low (0.5 mg kg-1) or high (2 mg kg-1) doses of L-Glutamine daily, with 5-FU (50 mg kg-1) administered between days six and nine. Mice receiving only 5-FU exhibited weight loss, diarrhea, abnormal cell growth, and colonic inflammation, correlated with decreased mucin proteins, increased endotoxins, reduced fecal short-chain fatty acids, and altered gut microbiota. Glutamine supplementation counteracted these effects by inhibiting the Toll-like receptor 4/nuclear factor kappa B (TLR4/NF-κB) pathway, modulating nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) oxidative stress proteins, and increasing mammalian target of rapamycin (mTOR) levels, thereby enhancing microbial diversity and protecting intestinal mucosa.

CONCLUSIONS

These findings underscore glutamine's potential in preventing 5-FU-induced mucositis by modulating gut microbiota and inflammation pathways.

hUC-MSCs therapy for Crohn's disease: efficacy in TNBS-induced colitis in rats and pilot clinical study

BACKGROUND

The use of mesenchymal stem cells (MSCs) has recently emerged as a promising new therapeutic strategy for many diseases including perianal fistulizing Crohn's disease (CD). Whether hUC-MSCs can promote the healing of luminal ulcer in CD has not been studied so far.

METHODS

The model of TNBS-induced colitis in rats was used to confirm the efficacy of hUC-MSCs in the treatment of CD. Then, seventeen CD patients refractory to or unsuitable for currently available therapies were enrolled and received once submucosal local injection through colonoscopy combined with once intravenous drip on the next day. All patients received a 24-week follow-up. Clinical and laboratory assessments were monitored at baseline, week 4, 8, 12, and 24. Endoscopic evaluations were conducted at baseline and week 12. Mucosal specimens were obtained at the margin of lesions by endoscopy biopsies and used for RNA sequencing. Two hUC-MSCs co-culture systems were established in vitro, one with the mucosa specimens and the other with M1 macrophages induced from THP1. The expressions of genes representing inflammation (TNFα, IL-6, and IL-1β) and intestinal barrier function (ZO1, CLAUDIN1, and CDH1) were tested by RT-PCR.

FINDINGS

hUC-MSCs treatment increased body weight and decreased disease activity index (DAI), colon macroscopic damage index (CMDI), and histopathological score (HPS) of rats with TNBS-induced colitis. The results of the clinical study also showed that this mode of hUC-MSCs application was associated with regression of intestinal ulceration. Eight patients (47%) got endoscopic responses (SES-CD improvement of ≥50% from baseline) and three patients (17.65%) got mucosal healing (SES-CD is zero), with a parallel improvement of clinical and laboratory parameters without serious adverse events. RNA sequencing showed hUC-MSCs therapy was associated with an upregulation of transcripts linked to intestinal epithelial barrier integrity and a downregulation of inflammatory signaling pathways in the intestinal mucosa, especially the TNF signaling pathway, IL-17 signaling pathway, and TLR signaling pathway. RNA expression of intestinal epithelial tight junction protein (ZO1, CLAUDIN1, and CDH1), and the RNA expression of major intestinal inflammatory factors in CD (IL-1β, IL-6, and TNFα, p < 0.001 for all) were improved significantly. Moreover, hUC-MSCs could attenuate the polarization of M1 macrophage induced from THP1, thereby decreasing the mRNA expression of IL-1β, IL-6, and TNFα significantly (p < 0.05 for all). TSG-6 expression was evaluated in hUC-MSCs culture supernatant after treatment with TNFα, IFNγ, and LPS for 48 h. And hUC-MSCs could inhibit the phosphorylation of JAK/STAT1 in the intestinal mucosa of CD patients.

INTERPRETATION

hUC-MSCs transplantation alleviated TNBS-induced colitis in rats. In this pilot clinical study, preliminary data suggested that this approach to administering hUC-MSCs might have potential for clinical efficacy and manageable safety in treating refractory CD, potentially providing hope for better outcomes. No serious adverse events were observed.

FUNDING

This work was funded by General Program of National Natural Science Foundation of China (Grant No. 82270639), the Scientific research project of Shanghai Municipal Health Committee (Grant No. 202240001), Specialty Feature Construction Project of Shanghai Pudong New Area Health Commission (Grant No. PWZzb2022-05), Shanghai East Hospital Youth Research and Cultivation Foundation program (Grant No. DFPY2022015), Peak Disciplines (Type IV) of Institutions of Higher Learning in Shanghai and Technology Development Project of Pudong Science, Technology and Economic Commission of Shanghai (Grant No. PKJ2021-Y08).

Effect of Salvia sclarea L. extract on growth performance, antioxidant capacity, and immune function in lambs

The aim of this experiment is to explore the effects of salvia sclarea extract on the growth performance, apparent nutrient digestibility, antioxidant capacity, and immune function of lambs. Sixty female lambs (Chinese Merino sheep) aged 2 months and weighing 20 ± 2 kg were selected and randomly divided into five groups of twelve lambs in each. While the control group (CK) received only basal feed, the experimental group was supplemented with different concentrations of salvia sclarea extract in the basal feed at 0.04 mL/kg (group CL1), 0.08 mL/kg (group CL2), 0.12 mL/kg (group CL3), and 0.16 mL/kg (group CL4). The feeding period was 85 days, including 15 days of pre-feeding and 70 days of regular feeding. Body weight and feed intake were recorded during the test period, and blood was collected at the end of the test for the determination of immune and antioxidant indices. The results showed that the average daily gain and average daily feed intake of lambs were significantly increased in CL3 group compared to CK group (p < 0.05). Also, the apparent nutrient digestibility of crude protein and neutral detergent fiber was significantly increased (p < 0.05). The Dry matter, acid detergent fiber and Ether extract were not significantly different (p > 0.05). The serum levels of superoxide dismutase, catalase, glutathione peroxidase, and antioxidant capacity were significantly higher in the CL2, CL3, and CL4 groups compared to CK group, while malondialdehyde levels were significantly lower (p < 0.05). The serum levels of immune globulin A, immune globulin G, immune globulin M, interferon-γ, and interleukin-10 were significantly higher and the levels of tumor necrosis factor-α and interleukin-1β were significantly lower in the CL2, CL3, and CL4 groups (p < 0.05). In conclusion, the addition of salvia sclarea extract to the ration promotes growth performance and nutrient digestion in lambs. Improvement of immune response by increasing immunoglobulin and cytokine concentrations. And it enhances the antioxidant status by increasing the antioxidant enzyme activity in lambs.

Introduction

This study aimed to explore the effects of Salvia sclarea extract on the growth performance, apparent nutrient digestibility, antioxidant capacity, and immune function of the lambs.

Methods

Sixty female lambs (Chinese Merino sheep) aged 2 months and weighing 20 ± 2 kg were selected and randomly divided into five groups of 12 lambs each. The control group (CK) received only basal feed, whereas the experimental group was supplemented with different concentrations of salvia sclarea extract in the basal feed at 0.04, 0.08, 0.12, and 0.16 mL/kg (CL1, CL2, CL3, and CL4, respectively). The feeding period was 85 days, including 15 days of pre-feeding and 70 days of regular feeding. Body weight and feed intake were recorded during the test period, and blood was collected at the end of the test to determine immune and antioxidant indices.

Results

The results showed that the average daily weight gain and feed intake of the lambs were significantly higher in the CL3 group than in the CK group (p < 0.05). In addition, the apparent nutrient digestibility of crude protein and neutral detergent fiber increased significantly (p < 0.05). The dry matter, acid detergent fiber, and ether extract were not significantly different (p > 0.05). Serum levels of superoxide dismutase, catalase, and glutathione peroxidase and antioxidant capacity were significantly higher in the CL2, CL3, and CL4 groups than in the CK group, whereas malondialdehyde levels were significantly lower (p < 0.05). The serum levels of immune globulin immune globulin A, immune globulin G, immune globulin M, interferon-γ, and interleukin-10 were significantly higher and the levels of tumor necrosis factor-α and interleukin-1β were significantly lower in the CL2, CL3, and CL4 groups (p < 0.05).

Discussion

In conclusion, the addition of the S. sclarea extract to the diet promoted growth performance and nutrient digestion in lambs. Immune response was improved by increasing Ig and cytokine concentrations. It enhances antioxidant status by increasing antioxidant enzyme activity in lambs.

Clostridium butyricum isolated from giant panda can attenuate dextran sodium sulfate-induced colitis in mice

Objective

Probiotics are beneficial to the intestinal barrier, but few studies have investigated probiotics from giant pandas. This study aims to explore the preventive effects of giant panda-derived Clostridium butyricum on dextran sodium sulfate (DSS)-induced colitis in mice.

Methods

Clostridium butyricum was administered to mice 14 days before administering DSS treatment to induce enteritis.

Results

Clostridium butyricum B14 could more effectively prevent colitis in mice than C. butyricum B13. C. butyricum B14 protected the mouse colon by decreasing the histology index and serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels, which improved intestinal inflammation-related symptoms. In addition, the treatment led to the regulation of the expression of Tifa, Igkv12-89, and Nr1d1, which in turn inhibited immune pathways. The expression of Muc4, Lama3, Cldn4, Cldn3, Ocln, Zo1, Zo2, and Snai is related the intestinal mucosal barrier. 16S sequencing shows that the C. butyricum B14 significantly increased the abundance of certain intestinal probiotics. Overall, C. butyricum B14 exerted a preventive effect on colitis in mice by inhibiting immune responses, enhancing the intestinal barrier and increasing the abundance of probiotic species. Thus, C. butyricum B14 administration helps regulate the balance of the intestinal microecology. It can suppress immune pathways and enhance barrier-protective proteins.

Agaro-oligosaccharides mitigate deoxynivalenol-induced intestinal inflammation by regulating gut microbiota and enhancing intestinal barrier function in mice

Agarose-derived agaro-oligosaccharides (AgaroS) have been extensively studied in terms of structures and bioactivities; they reportedly possess antioxidant and anti-inflammatory activities that maintain intestinal homeostasis and host health. However, the protective effects of AgaroS on deoxynivalenol (DON)-induced intestinal dysfunction remain unclear. We investigated the effects of AgaroS on DON-induced intestinal dysfunction in mice and explored the underlying protective mechanisms. In total, 32 mice were randomly allocated to four treatments (n = 8 each) for 28 days. From day 1 to day 21, the control (CON) and DON groups received oral phosphate-buffered saline (200 μL per day); the AgaroS and AgaroS + DON groups received 200 mg AgaroS per kg body weight once daily by orogastric gavage. Experimental intestinal injury was induced by adding DON (4.8 mg per kg body weight) via gavage from day 21 to day 28. Phosphate-buffered saline was administered once daily by gavage in the CON and AgaroS groups. Herein, AgaroS supplementation led to a higher final body weight and smaller body weight loss and a lower concentration of plasma inflammatory cytokines, compared with the DON group. The DON group showed a significantly reduced ileal villus height and villus height/crypt depth, compared with the CON and AgaroS + DON groups. However, AgaroS supplementation improved DON-induced intestinal injury in mice. Compared with the DON group, ileal and colonic protein expression levels of claudin, occludin, Ki67, and mucin2 were significantly higher in the AgaroS supplementation group. Colonic levels of the anti-inflammatory cytokine IL-1β tended to be higher in the DON group than in the AgaroS + DON group. AgaroS altered the gut microbiota composition, accompanied by increased production of short-chain fatty acids in mice. In conclusion, our findings highlight a promising anti-mycotoxin approach whereby AgaroS alleviate DON-induced intestinal inflammation by modulating intestinal barrier functional integrity and gut microbiota in mice.

Maternal supplementation with konjac glucomannan improves maternal microbiota for healthier offspring during lactation

BACKGROUND

The maternal diet during gestation and lactation affects the health of the offspring. Konjac glucomannan (KGM) is a significantly functional polysaccharide in food research, possessing both antioxidant and prebiotic properties. However, the mechanisms of how KGM regulates maternal nutrition remain insufficient and limited. This study aimed to investigate maternal supplementation with KGM during late gestation and lactation to benefit both maternal and offspring generations.

RESULTS

Our findings indicate that KGM improves serum low density lipoprotein cholesterol (LDL-C) and antioxidant capacity. Furthermore, the KGM group displayed a significant increase in the feed intake-related hormones neuropeptide tyrosine (NPY), Ghrelin, and adenosine monophosphate-activated kinase (AMPK) levels. KGM modified the relative abundance of Clostridium, Candidatus Saccharimonas, unclassified Firmicutes, and unclassified Christensenellaceae in sow feces. Acetate, valerate, and isobutyrate were also improved in the feces of sows in the KGM group. These are potential target bacterial genera that may modulate the host's health. Furthermore, Spearman's correlation analysis unveiled significant correlations between the altered bacteria genus and feed intake-related hormones. More importantly, KGM reduced interleukin-6 (IL-6) levels in milk, further improved IL-10 levels, and reduced zonulin levels in the serum of offspring.

CONCLUSION

In conclusion, maternal dietary supplementation with KGM during late gestation and lactation improves maternal nutritional status by modifying maternal microbial and increasing lactation feed intake, which benefits the anti-inflammatory capacity of the offspring serum. © 2024 Society of Chemical Industry.

Trends in 3D models of inflammatory bowel disease

Inflammatory bowel disease (IBD) encompasses a set of chronic inflammatory conditions, namely Crohn's disease and ulcerative colitis. Despite all advances in the management of IBD, a definitive cure is not available, largely due to a lack of a holistic understanding of its etiology and pathophysiology. Several in vitro, in vivo, and ex vivo models have been developed over the past few decades in order to abbreviate remaining gaps. The establishment of reliable and predictable in vitro intestinal inflammation models may indeed provide valuable tools to expedite and validate the development of therapies for IBD. Three-dimensional (3D) models provide a more accurate representation of the different layers of the intestine, contributing to a stronger impact on drug screening and research on intestinal inflammation, and bridging the gap between in vitro and in vivo research. This work provides a critical overview on the state-of-the-art on existing 3D models of intestinal inflammation and discusses the remaining challenges, providing insights on possible pathways towards achieving IBD mimetic models. We also address some of the main challenges faced by implementing cell culture models in IBD research while bearing in mind clinical translational aspects.

The exposure in ovo to glyphosate on the integrity of intestinal epithelial tight junctions of chicks

Glyphosate is an ingredient widely used in various commercial formulations, including Roundup®. This study focused on tight junctions and the expression of inflammatory genes in the small intestine of chicks. On the sixth day of embryonic development, the eggs were randomly assigned to three groups: the control group (CON, n = 60), the glyphosate group (GLYP, n = 60), which received 10 mg of active glyphosate/kg egg mass, and the Roundup®-based glyphosate group also received 10 mg of glyphosate. The results indicated that the chicks exposed to glyphosate or Roundup® exhibited signs of oxidative stress. Additionally, histopathological alterations in the small intestine tissues included villi fusion, complete fusion of some intestinal villi, a reduced number of goblet cells, and necrosis of some submucosal epithelial cells in chicks. Genes related to the small intestine (ZO-1, ZO-2, Claudin-1, Claudin-3, JAM2, and Occludin), as well as the levels of pro-inflammatory cytokines (IFNγ, IL-1β, and IL-6), exhibited significant changes in the groups exposed to glyphosate or Roundup® compared to the control group. In conclusion, the toxicity of pure glyphosate or Roundup® likely disrupts the small intestine of chicks by modulating the expression of genes associated with tight junctions in the small intestine.

Bergenin Alleviates Ulcerative Colitis By Decreasing Gut Commensal Bacteroides vulgatus-Mediated Elevated Branched-Chain Amino Acids

Ulcerative colitis is closely associated with the dysregulation of gut microbiota. There is growing evidence that natural products may improve ulcerative colitis by regulating the gut microbiota. In this research, we demonstrated that bergenin, a naturally occurring isocoumarin, significantly ameliorates colitis symptoms in dextran sulfate sodium (DSS)-induced mice. Transcriptomic analysis and Caco-2 cell assays revealed that bergenin could ameliorate ulcerative colitis by inhibiting TLR4 and regulating NF-κB and mTOR phosphorylation. 16S rRNA sequencing and metabolomics analyses revealed that bergenin could improve gut microbiota dysbiosis by decreasing branched-chain amino acid (BCAA) levels. BCAA intervention mediated the mTOR/p70S6K signaling pathway to exacerbate the symptoms of ulcerative colitis in mice. Notably, bergenin greatly decreased the symbiotic bacteria Bacteroides vulgatus (B. vulgatus), and the gavage of B. vulgatus increased BCAA concentrations and aggravated the symptoms of ulcerative colitis in mice. Our findings suggest that gut microbiota-mediated BCAA metabolism plays a vital role in the protective effect of bergenin on ulcerative colitis, providing novel insights for ulcerative colitis prevention through manipulation of the gut microbiota.

Effects of Dietary Aflatoxin B1 on Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) Growth, Intestinal Health, and Muscle Quality

This study investigated the effects of varying doses of dietary aflatoxin B1 (AFB1) on the growth, intestinal health, and muscle quality of hybrid grouper. Four diets with varying AFB1 concentrations (0, 30, 445, and 2,230 μg kg-1) were used. Elevating AFB1 concentrations led to a decline in growth indexes, specifically the weight gain rate and the specific growth rate, although the survival rate remained unchanged. Morphological indicators showed a dose-dependent decline with AFB1 exposure. Intestinal MDA content and hindgut reactive oxygen species (ROS) levels increased, while antioxidant indexes and digestive enzymes decreased with higher AFB1 levels. AFB1 negatively influenced hindgut tight junction protein and antioxidant-related gene expression while promoting inflammation-related gene expression. The presence of AFB1 in the experiment led to a decrease in beneficial intestinal bacteria, such as Prevotella, and an increase in harmful intestinal bacteria, such as Prevotellaceae_NK3B31_group. Muscle lipid and unsaturated fatty acid content significantly decreased, while muscle protein and liver AFB1 content increased dramatically with higher AFB1 concentrations. AFB1 caused myofibrillar cleavage and myofilament damage, leading to increased spaces between muscle fibers. In conclusion, diets with AFB1 levels exceeding 30 μg kg-1 inhibited hybrid grouper growth, while levels surpassing 445 μg kg-1 resulted in hindgut ROS accumulation, inflammation, elevated intestinal permeability, reduced digestive enzyme activity, and compromised muscle quality.

Fermentation enhances the amelioration effect of bee pollen on Caco-2 monolayer epithelial barrier dysfunction based on NF-κB-mediated MLCK-MLC signaling pathway

Intestinal barrier integrity is essential for normal nutrient digestion and absorption and disease resistance. This study aims to investigate how fermentation affects the ameliorative effect of bee pollen on the intestinal barrier dysfunction stimulated by interferon-γ and tumor necrosis factor (IFN-γ/TNF-α) cytokines. The results indicated that fermentation enhances the alleviating effect of bee pollen on intestinal barrier dysfunction (including elevated trans epithelial electrical resistance and decreased paracellular permeability). In addition, fermented bee pollen (FBP) significantly decreased (p < 0.05) the secretion levels of interleukin (IL)-6, IL-8, and IL-1β and expression of cyclooxygenase (COX)-2 protein in intestinal barrier cells. Furthermore, fermentation improved the ability of bee pollen to up-regulate the expression of tight junction proteins including zonula occludens (ZO)-1, occluding, and claudin-1. Notably, FBP showed stronger ability to inhibit the expression of nuclear factor kappa-B (NF-κB) mediated myosin light chain kinase (MLCK) and myosin light chain (MLC) signaling pathway associated with phosphorylated proteins. Overall, our results indicated that fermentation enhances the protective effect of bee pollen on the intestinal barrier, and FBP has promising potential to be used as a novel functional food to protect the intestinal barrier.

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

BACKGROUND

Zinc glycine chelate (Zn-Gly) has anti-inflammation and growth-promoting properties; however, the mechanism of Zn-Gly contribution to gut barrier function in Cherry Valley ducks during intestinal inflammation is unknown. Three-hundred 1-day-old ducks were divided into 5 groups (6 replicates and 10 ducks per replicate) in a completely randomized design: the control and dextran sulfate sodium (DSS) groups were fed a corn-soybean meal basal diet, and experimental groups received supplements of 70, 120 or 170 mg/kg Zn in form of Zn-Gly. The DSS and treatment groups were given 2 mL of 0.45 g/mL DSS daily during d 15-21, and the control group received normal saline. The experiment lasted 21 d.

RESULTS

Compared with DSS group, 70, 120 and 170 mg/kg Zn significantly increased body weight (BW), villus height and the ratio of villus to crypt, and significantly decreased the crypt depth of jejunum at 21 d. The number of goblet cells in jejunal villi in the Zn-Gly group was significantly increased by periodic acid-Schiff staining. Compared with control, the content of intestinal permeability marker D-lactic acid (D-LA) and fluxes of fluorescein isothiocyanate (FITC-D) in plasma of DSS group significantly increased, and 170 mg/kg Zn supplementation significantly decreased the D-LA content and FITC-D fluxes. Compared with control, contents of plasma, jejunum endotoxin and jejunum pro-inflammatory factors IL-1β, IL-6 and TNF-α were significantly increased in DSS group, and were significantly decreased by 170 mg/kg Zn supplementation. Dietary Zn significantly increased the contents of anti-inflammatory factors IL-10, IL-22 and sIgA and IgG in jejunum. Real-time PCR and Western blot results showed that 170 mg/kg Zn supplementation significantly increased mRNA expression levels of CLDN-1 and expression of OCLN protein in jejunum, and decreased gene and protein expression of CLDN-2 compared with DSS group. The 120 mg/kg Zn significantly promoted the expressions of IL-22 and IgA. Dietary Zn-Gly supplementation significantly decreased pro-inflammatory genes IL-8 and TNF-α expression levels and TNF-α protein expression in jejunum. Additionally, Zn significantly reduced the gene and protein expression of TLR4, MYD88 and NF-κB p65.

CONCLUSIONS

Zn-Gly improved duck BW and alleviated intestinal injury by regulating intestinal morphology, barrier function and gut inflammation-related signal pathways TLR4/MYD88/NF-κB p65.

Gut toxicity of polystyrene microplastics and polychlorinated biphenyls to Eisenia fetida: Single and co-exposure effects with a focus on links between gut bacteria and bacterial translocation stemming from gut barrier damage

Microplastics' (MPs) ability to sorb and transport polychlorinated biphenyls (PCBs) in soil ecosystems warrants significant attention. Although organisms mainly encounter pollutants through the gut, the combined pollution impact of MPs and PCBs on soil fauna gut toxicity remains incompletely understood. Consequently, this study examined the gut toxicity of polystyrene MPs (PS-MPs) and PCB126 on Eisenia fetida, emphasizing the links between gut bacteria and bacterial translocation instigated by gut barrier impairment. Our findings underscored that E. fetida could ingest PS-MPs, which mitigated the PCB126 accumulation in E. fetida by 9.43 %. Exposure to PCB126 inhibited the expression of gut tight junction (TJ) protein genes. Although the presence of PS-MPs attenuated this suppression, it didn't alleviate gut barrier damage and bacterial translocation in the co-exposure group. This group demonstrated a significantly increased level of gut bacterial load (BLT, ANOVA, p = 0.005 vs control group) and lipopolysaccharide-binding protein (LBP, ANOVA, all p < 0.001 vs control, PCB, and PS groups), both of which displayed significant positive correlations with antibacterial defense. Furthermore, exposure to PS-MPs and PCB126, particularly within the co-exposure group, results in a marked decline in the dispersal ability of gut bacteria. This leads to dysbiosis (Adonis, R2 = 0.294, p = 0.001), with remarkable signature taxa such as Janthinobacterium, Microbacterium and Pseudomonas, being implicated in gut barrier dysfunction. This research illuminates the mechanism of gut toxicity induced by PS-MPs and PCB126 combined pollution in earthworms, providing novel insights for the ecological risk assessment of soil.

Protective effects of metformin in the pro-inflammatory cytokine induced intestinal organoids injury model

Pathogenesis of inflammatory bowel disease (IBD) accompanies disrupted intestinal tight junctions. However, many approaches of therapeutics for IBD are focused only on anti-inflammatory effects and most cellular experiments are based on two-dimensional cell lines which have insufficient circumstances of intestine. Thus, here, we used three-dimensional structure intestinal organoids to investigate effects of metformin in the in vitro IBD condition. In this study, we focused on both tight junctions and the levels of inflammatory cytokines. Metformin enhances the intestinal barrier in injured intestine via upregulation of AMP-activated protein kinase, dysfunction of which contributes to the pathogenesis of intestinal diseases. We aim to investigate the effects of metformin on cytokine-induced injured intestinal organoids. Tumor necrosis factor-alpha (TNF-α) was used to induce intestinal injury in an organoid model, and the effects of metformin were assessed. Cell viability and levels of inflammatory cytokines were quantified in addition to tight junction markers. Furthermore, 4 kDa FITC-dextran was used to assess intestinal permeability. The upregulation of inflammatory cytokine levels was alleviated by metformin, which also restored the intestinal epithelium permeability in TNF-α-treated injury organoids. We confirmed that claudin-2 and claudin-7, representative tight junction markers, were also protected by metformin treatment. This study confirms the protective effects of metformin, which could be used as a therapeutic strategy for inflammatory intestinal diseases.

Microalgae polysaccharides exert antioxidant and anti-inflammatory protective effects on human intestinal epithelial cells in vitro and dextran sodium sulfate-induced mouse colitis in vivo

Microalgae polysaccharides (MAPS) have emerged as novel prebiotics, but their direct effects on intestinal epithelial barrier are largely unknown. Here, MAPS isolated from Chlorella pyrenoidosa, Spirulina platensis, and Synechococcus sp. PCC 7002 were characterized as mainly branched heteropolysaccharides, and were bioavailable to Caco-2 cells based on fluorescein isothiocyanate labeling and flow cytometry analysis. These MAPS were equally effective to scavenge hydroxyl and superoxide radicals in vitro and to attenuate the H2O2-, dextran sodium sulfate-, tumor necrosis factor α-, and interleukin 1β-induced burst of intracellular reactive oxygen species and mitochondrial superoxide radicals, interleukin-8 production, cyclooxygenase-2 and inducible nitric oxide synthase expression, and/or tight junction disruption in polarized Caco-2 cells. MAPS and a positive drug Mesalazine were intragastrically administered to C57BL/6 mice daily for 7 d during and after 4-d dextran sodium sulfate exposure. Clinical signs and colon histopathology revealed equivalent anti-colitis efficacies of MAPS and Mesalazine, and based on biochemical analysis of colonic tight junction proteins, goblet cells, mucin 2 and trefoil factor 3 transcription, and colonic and peripheral pro-inflammatory cytokines, MAPS alleviated dextran sodium sulfate-induced intestinal epithelial barrier dysfunction, and their activities were even superior than Mesalazine. Overall, MAPS confer direct antioxidant and anti-inflammatory protection to intestinal epithelial barrier function.

Allergic Airway Inflammation Emerges from Gut Inflammation and Leakage in Mouse Model of Asthma

Asthma is an allergic airway inflammatory disease characterized by type 2 immune responses. Growing evidence suggests an association between allergic airways and intestinal diseases. However, the primary site of disease origin and initial mechanisms involved in the development of allergic airway inflammation (AAI) is not yet understood. Therefore, the initial contributing organs and mechanisms involved in the development of AAI are investigated using a mouse model of asthma. This study, without a local allergen challenge into the lungs, demonstrates a significant increase in intestinal inflammation with signature type-2 mediators including IL-4, IL-13, STAT6, eosinophils, and Th2 cells. In addition, gut leakage and mRNA expressions of gut leakage markers significantly increase in the intestine. Moreover, reduced mRNA expressions of tight junction proteins are observed in gut and interestingly, in lung tissues. Furthermore, in lung tissues, an increased pulmonary barrier permeability and IL-4 and IL-13 levels associated with significant increase of lipopolysaccharide-binding protein (LBP-gut leakage marker) and eosinophils are observed. However, with local allergen challenges into the lungs, these mechanisms are further enhanced in both gut and lungs. In conclusion, the primary gut originated inflammatory responses translocates into the lungs to orchestrate AAI in a mouse model of asthma.

Lactiplantibacillus plantarum HY7718 Improves Intestinal Integrity in a DSS-Induced Ulcerative Colitis Mouse Model by Suppressing Inflammation through Modulation of the Gut Microbiota

Inflammatory bowel disease (IBD), a chronic condition that causes persistent inflammation in the digestive system, is closely associated with the intestinal microbiome. Here, we evaluated the effects of Lactiplantibacillus plantarum HY7718 (HY7718) on IBD symptoms in mice with dextran sulfate sodium (DSS)-induced colitis. Oral administration of HY7718 led to significant improvement in the disease activity index score and the histological index, as well as preventing weight loss, in model mice. HY7718 upregulated the expression of intestinal tight junction (TJ)-related genes and downregulated the expression of genes encoding pro-inflammatory cytokines and genes involved in the TLR/MyD88/NF-κB signaling pathway. Additionally, HY7718 reduced the blood levels of pro-inflammatory cytokines, as well as reversing DSS-induced changes to the composition of the intestinal microbiome. HY7718 also increased the percentage of beneficial bacteria (Lactiplantibacillus and Bifidobacterium), which correlated positively with the expression of intestinal TJ-related genes. Finally, HY7718 decreased the population of pathogens such as Escherichia, which correlated with IBD symptoms. The data suggest that HY7718 improves intestinal integrity in colitis model mice by regulating the expression of TJ proteins and inflammatory cytokines, as well as the composition of the intestinal microflora. Thus, L. plantarum HY7718 may be suitable as a functional supplement that improves IBD symptoms and gut health.

Feeding Strategies with Multi-Strain Probiotics Affect Growth, Health Condition, and Disease Resistance in Asian Seabass (Lates calcarifer)

A 16-week feeding trial was done to examine the impacts of continuous feeding (CF) or pulse-feeding (PF) of multi-strain probiotics on Asian seabass (Lates calcarifer, 30.0 ± 0.1 g) juveniles. In this study, three different multi-strain probiotic mixtures were added to a basal diet, including (I) a mixture of different strains of Lactobacillus plantarum, (II) a mixture of the first probiotic (I) + L. delbrueckii sub bulgaricus, L. rhamnosus and L. acidophilus, and (III) a mixture of the second probiotic (II) + two quorum quenching (QQ) bacteria (Bacillus thuringiensis QQ1 and B. cereus QQ2). CF (every day) or PF (every two weeks) strategies were applied for using the abovementioned probiotics to design seven experimental groups including C (control, without probiotics), CF-I (continuous feeding of fish with the probiotic mixture I), CF-II (continuous feeding of fish with the probiotic mixture II), CF-III (continuous feeding of fish with the probiotic mixture III), PF-I (pulse-feeding of fish with the probiotic mixture I), PF-II (pulse-feeding of fish with the probiotic mixture II), and PF-III (pulse-feeding of fish with the probiotic mixture III). Four hundred and twenty fish were stocked into 21 circular polyethylene tanks with 220 L volume (20 fish/tank). Each dietary treatment had three replicates. Tanks were supplied with seawater (temperature = 30.5 °C, salinity = 45 g L-1) in a flow-throw system. Fish in CF-I, CF-II, and CF-III had higher growth rate (ca. 113-145%) and better feed conversion ratio than fish fed C and PF-I (P < 0.05). Fish in the CF-III group had the highest protease activity. Continuous feeding strategy resulted in a higher amount of glutathione and catalase activities in both the liver and plasma as well as higher superoxide dismutase activity in the liver of fish. Pulse-feeding strategy resulted in lower plasma lactate dehydrogenase and aspartate aminotransferase levels than the CF strategy. Regardless of feeding strategy, different probiotic mixtures significantly enhanced blood hemoglobin and hematocrit levels compared to the control. Continuous feeding with the multi-strain probiotics resulted in a higher survival rate against Vibrio harveyi than the PF method. Continuous feeding induced higher mRNA transcription levels of granulocyte-macrophage colony-forming cells and interleukin 10 genes in the gut of fish than PF strategy. In conclusion, continuous feeding with multi-strain probiotics is better than pulse-feeding on growth, feed utilization, antioxidant capacity, and the gut's immune-related genes and led to higher resistance of L. calcarifer in challenge with V. harveyi.

A proteomic insight reveals the role of food-associated Lactiplantibacillus plantarum C9O4 in reverting intestinal inflammation

Nowadays, Western diets and lifestyle lead to an increasing occurrence of chronic gut inflammation that represents an emerging health concern with still a lack of successful therapies. Fermented foods, and their associated lactic acid bacteria, have recently regained popularity for their probiotic potential including the maintenance of gut homeostasis by modulating the immune and inflammatory response. Our study aims to investigate the crosstalk between the food-borne strain Lactiplantibacillus plantarum C9O4 and intestinal epithelial cells in an in vitro inflammation model. Cytokines profile shows the ability of C9O4 to significantly reduce levels of IL-2, IL-5, IL-6, and IFN-γ. Proteomic functional analysis reveals an immunoregulatory role of C9O4, able to revert the detrimental effects of IFN-γ through the JAK/STAT pathway in inflamed intestinal cells. These results suggest a promising therapeutic role of fermented food-associated microbes for the management of gastrointestinal inflammatory diseases. Data are available via ProteomeXchange with identifier PXD042175.

Deciphering the interplay between LPS/TLR4 pathways, neurotransmitter, and deltamethrin-induced depressive-like behavior: Perspectives from the gut-brain axis

The improper use of deltamethrin (DM) can result in its accumulation in soil, water, food, and even the human body, which is associated with an elevated risk of neurotoxicity and behavioral abnormalities; however, the underlying mechanisms remain insufficiently investigated. Emerging evidence underscores the significance of the gut-brain axis in central nervous system (CNS) dysfunctions. Accordingly, this study investigates the role of the gut-brain axis in DM-induced behavioral anomalies in mice. The results showed that DM exposure induced depressive-like behavior, and the hippocampus, the region that is responsible for the modulation of emotional behavior, showed structural integrity disrupted (neuronal nuclear shrinkage and decreased tight junction protein expression). In addition, DM exposure led to compromised gut barrier integrity (disruptions on crypt surfaces and decreased tight junction protein expression), which might contribute to the gut bacterial-derived lipopolysaccharide (LPS) leakage into the bloodstream and reaching the brain, triggering LPS/toll-like receptor (TLR) 4 -mediated increases in brain pro-inflammatory cytokines. Subsequently, we observed a disturbance in neurotransmitter metabolic pathways following DM exposure, which inhibited the production of 5-hydroxytryptamine (5-HT). Additionally, DM exposure resulted in gut microbiota dysbiosis. Characteristic bacteria, such as Alistipes, Bifidobacterium, Gram-negative bacterium cTPY-13, and Odoribacter exhibited significant correlations with behavior, tight junction proteins, inflammatory response, and neurotransmitters. Further fecal microbiota transplantation (FMT) experiments suggested that DM-induced gut microbiota dysbiosis might contribute to depressive-like behavior. These results provide a new perspective on the toxicity mechanism of DM, indicating that its neurotoxicity may be partially regulated by the microbiota-gut-brain axis.

Exploring the links between necrotizing enterocolitis and cow's milk protein allergy in preterm infants: a narrative review

A broad range of allergic disorders and intolerance are associated with cow's milk protein in the infant diet. Allergy and intolerance to cow's milk proteins are commonly recognized in the healthy term infant, and the prevalence cow's milk protein intolerance (CMPI) varies widely but 5 challenge confirmed studies free from selection bias ranged from 1.9%-4.9%. These disorders are classified by the presence of IgE, non-IgE or T-cell-mediated signaling. Additionally, the severity of these adverse food reactions can range from mild gastrointestinal symptoms to severe sepsis-like episodes, as in the case of food protein-induced enterocolitis syndrome (FPIES). Food protein-induced intolerance in the healthy young infant lies in stark contrast to enterocolitis that typically occurs in the preterm neonate. Necrotizing enterocolitis (NEC) is a distinct progressive disease process, usually characterized by a high mortality rate, with a risk of death from 30% to 50%. While its exact etiology is unclear, its main triggers include formula (cow's milk protein), hypoxia, perfusion-related issues, and unregulated inflammation in the premature intestine. The distinction between NEC and cow's milk protein intolerance is difficult to discern in some cases. In the late preterm population, infants with colitis can have both NEC and cow's milk intolerance on the differential. In infants with multiple episodes of mild NEC, cow's milk protein intolerance may be the underlying diagnosis. In this review, we compare the pathophysiological characteristics, diagnosis and treatment of disorders of cow's milk protein intolerance with the entity of preterm NEC. This review highlights similarities in both entities and may inspire future cross-disciplinary research.

Mesobiliverdin IXα-enriched microalgae feed additive eliminates reliance on antibiotic tylosin to promote intestinal health of weaning piglets

Weaning is a critical period in raising pigs. Novel animal feed additives that promote gut health and regulate immune function of piglets without antibiotics are needed. In this study, we aimed to test the ability of mesobiliverdin IXα-enriched microalgae (MBV IXα-enriched microalgae) to eliminate reliance on antibiotics to promote intestinal health in piglets. Eighty 28-day-old weaned piglets were randomly allocated to four groups each with four replicate pens and five piglets per pen. The dietary treatments were a basal diet as control (NC), basal diet plus 0.05% tylosin (PC), basal diet plus 0.1% or 0.5% MBV IXα-enriched microalgae as low (MBV-SP1) or high (MBV-SP2) dose respectively. All treated animals showed no significant differences in live weight, average daily gain and feed efficiency compared to control animals. Histological examination showed that MBV-SP1 and particularly MBV-SP2 increased the ratio of villus height to crypt depth in the jejunum and ileum compared to NC (p < 0.05). Similarly, tylosin treatment also increased villi lengths and the ratio of villus height to crypt depth in the jejunum and ileum compared to the NC (p < 0.05). MBV-SP1 and particularly MBV-SP2 reduced the levels of inflammatory cytokines interleukin-6 and tumour necrosis factor-alpha in the small intestine. MBV-SP2 and tylosin similarly reduced the lipid peroxidation marker (TBARS value) in the duodenum and ileum. In conclusion, feed supplementation with MBV IXα-enriched microalgae improved gut health by villus height and production of immunomodulators that correlated with down-regulated secretion of inflammatory cytokines.

Cinnamon (Cinnamomum cassia) hot water extract improves inflammation and tight junctions in the intestine in vitro and in vivo

The natural byproduct Cinnamomum cassia was widely used in ancient Asia to cure disease because of its various pharmacological effects. Despite its ethnomedicinal benefits, few studies on the intestinal anti-inflammatory effect of C. cassia have been reported. Therefore, this study aimed to evaluate the potential beneficial effects of C. cassia on the intestine in vitro and in vivo. Herein, the effects of cinnamon hot water extract (CWE) on tight junction (TJ) barrier function, transepithelial electrical resistance, and mRNA expression were confirmed in Caco-2 cells. The CWE treatment groups showed significantly enhanced cell permeability, proinflammatory cytokine mRNA expression, and TJ expression. CWE-treated mice showed an improved histological index and decreased cytokine concentrations compared with those of colitis model mice. These results suggest that CWE alleviated inflammatory damage and improved the TJ barrier, indicating that CWE may be used as a functional food to improve intestinal health.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01292-3.

Effects of combined application of benzoic acid and 1-monolaurin on growth performance, nutrient digestibility, gut microbiome and inflammatory factor levels in weaned piglets

BACKGROUND

Our previous study observed that benzoic acid and 1-monolaurin have a synergistic bactericidal effect. Moreover, their improvement effect of benzoic acid and 1-monolaurin on the growth performance and diarrhea of weaned piglets was better than the two feedings alone. However, it is not clear how the combination of benzoic acid and 1-monolaurin affects the growth performance of weaned piglets. Therefore, 100 weaned piglets (mean weight 7.03 ± 1.04 kg, mean weaning age 26 d) were randomly divided into two groups: (1) basal diet control (CON); (2) basal diet supplemented with 0.6% benzoic acid and 0.1% 1-monolaurin (CA). The experiment lasted 28 days after weaning. The effects of benzoic acid and 1-monolaurin supplementation on growth performance, apparent nutrient digestibility, intestinal flora composition and function, and inflammatory factor levels of weaned piglets were investigated.

RESULTS

The feed conversion efficiency of piglets in the CA group between 15 and 28 d and 1 and 28 d after weaning was significantly higher than that in the CON group (P < 0.05). Additionally, the diarrhea proportion and frequency of piglets in the CA group 1-14 days post-weaning were significantly decreased (P < 0.05). The apparent digestibility of dry matter, organic matter and crude protein of piglets in the CA group was significantly higher than the CON group on days 14 and 28 (P < 0.05). The microbial composition in the cecal digesta of piglets was detected. The results indicated that the CA group piglets were significantly supplemented with g_YRC22 at day 14 and g_Treponema, g_Pseudomonas, and g_Lachnobacterium at day 28 (P < 0.05; log LDA > 2). No significant difference was observed between the CON and CA groups in the content of short-chain fatty acids. In addition, serum IL-1β level significantly decreased at day 28 in the CA group compared with the CON group, while serum endotoxin content was significantly reduced at day 14.

CONCLUSION

Therefore, dietary supplementation of 0.6% benzoic acid and 0.1% 1-monolaurin enhanced growth performance and nutrient digestibility, affected gut microflora composition, and decreased systemic inflammatory response and intestinal permeability of weaned piglets. These outcomes provide a theoretical basis for applying of benzoic acid and 1-monolaurin over weaned piglets.

Konjac glucomannan-assisted curcumin alleviated dextran sulfate sodium-induced mice colitis via regulating immune response and maintaining intestinal barrier integrity

Curcumin has been proven to be an effective strategy for reducing inflammatory responses. However, low bioavailability and instability at the physiological pH have limited its anti-inflammatory activity in ulcerative colitis patients. In the present study, a complex of curcumin and konjac glucomannan (KGM) effectively inhibited intestinal inflammation and this effect was associated with KGM degradation degrees. Results demonstrated that treatment with the complex markedly mitigated colitis symptoms and decreased inflammatory cytokines levels, especially in the complex treatment groups with K110 (KGM treated in 110 °C) and konjac oligosaccharides (KOSs). Furthermore, increasing the KOS content in KOC (the complex of curcumin and KOS) promoted the gene expressions of the intestinal barrier and inhibited the gene expressions of inflammatory cytokines, as well as improved gut microbiota dysregulation. Overall, our studies suggest that the complex of curcumin and KGM exerts effective anti-inflammatory effects by regulating the intestinal immune response and modulating microbiota diversity and composition.

The effects of sodium butyrate (NaB) combination with soy saponin dietary supplementation on the growth parameters, intestinal performance and immune-related genes expression of hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂)

Soy saponins are generally known to have negative effects on growth and the intestines of aquatic animals, and appropriate levels of sodium butyrate (NaB) may provide some mitigating effects. We investigated the effects of low and high levels of soy saponin and the protective effects of NaB (based on high level of soy saponin) on growth, serum cytokines, distal intestinal histopathology, and inflammation in hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). The experiment included four groups: fishmeal group (FM, 0.00% saponin and 0.00% NaB), low saponin group (SL, 0.30% saponin and 0.00% NaB), high saponin group (SH, 1.50% saponin and 0.00% NaB) and high saponin with NaB group (SH-NaB, 1.50% saponin and 0.13% NaB). The results showed compared to FM, the final body weight (FBW) and weight gain (WG) were significantly higher and lower in SL and SH, respectively (P < 0.05). Compared to SH, the FBW and WG were significant higher in SH-NaB (P < 0.05). In the serum, compared to FM, the interferon γ (IFN-γ) and interleukin-1β (IL-1β) levels in SH were significantly increased (P < 0.05). Compared to SH, the IFN-γ level was significantly decreased in SH-NaB (P < 0.05). In the distal intestine, based on Alcian Blue-Periodic Acid-Schiff (AB-PAS) observation, the goblet cell/μm was significantly increased and decreased in the SL and SH, respectively, compared to FM. The intestinal diameter/plica height ratio in the SH was significantly higher than those in the FM, SL and SH-NaB (P < 0.05). The NO and ONOO- levels in the SH were significantly higher than that in FM and SL (P < 0.05). At the transcriptional level in the distal intestine, compared to FM, the mRNA levels of tumor necrosis factor (tnfα), il1β, interleukin-8 (il8) and ifnγ were significantly up-regulated in the SH (P < 0.05). Compared to the SH, tnfα, il8 and ifnγ were significantly down-regulated in the SH-NaB (P < 0.05). Compared to the FM, the mRNA levels of claudin3, claudin15, zo2 and zo3 were significantly up-regulated in the SL (P < 0.05). The mRNA levels of occludin, claudin3, claudin12, claudin15, zo1, zo2 and zo3 were significantly down-regulated in the SH compared to the FM (P < 0.05). Additionally, compared to the SH, the mRNA levels of occludin, claudin3, claudin12, claudin15, zo1, zo2 and zo3 were significantly up-regulated in the SH-NaB (P < 0.05). After the 7-day Vibrio parahaemolyticus challenge test, the survival was significantly higher and lower in the SL and SH, respectively, compared to FM (P < 0.05). Overall, low and high levels of soy saponins had positive and negative effects on growth, disease resistance, serum cytokines, and distal intestinal development and anti-inflammation, respectively, in hybrid grouper. NaB effectively increased disease resistance and improved distal intestinal inflammation in hybrid grouper, but the effects of NaB were mainly observed in improving distal intestinal tight junctions.

A blend of selected botanicals maintains intestinal epithelial integrity and reduces susceptibility to Escherichia coli F4 infection by modulating acute and chronic inflammation in vitro

In the pig production cycle, the most delicate phase is weaning, a sudden and early change that requires a quick adaptation, at the cost of developing inflammation and oxidation, especially at the intestinal level. In this period, pathogens like enterotoxigenic Escherichia coli (ETEC) contribute to the establishment of diarrhea, with long-lasting detrimental effects. Botanicals and their single bioactive components represent sustainable well-recognized tools in animal nutrition thanks to their wide-ranging beneficial functions. The aim of this study was to investigate the in vitro mechanism of action of a blend of botanicals (BOT), composed of thymol, grapeseed extract, and capsicum oleoresin, in supporting intestinal cell health during inflammatory challenges and ETEC infections. To reach this, we performed inflammatory and ETEC challenges on Caco-2 cells treated with BOT, measuring epithelial integrity, cellular oxidative stress, bacterial translocation and adhesion, gene expression levels, and examining tight junction distribution. BOT protected enterocytes against acute inflammation: while the challenge reduced epithelial tightness by 40%, BOT significantly limited its drop to 30%, also allowing faster recovery rates. In the case of chronic inflammation, BOT systematically improved by an average of 25% the integrity of challenged cells (p < 0.05). Moreover, when cells were infected with ETEC, BOT maintained epithelial integrity at the same level as an effective antibiotic and significantly reduced bacterial translocation by 1 log average. The mode of action of BOT was strictly related to the modulation of the inflammatory response, protecting tight junctions' expression and structure. In addition, BOT influenced ETEC adhesion to intestinal cells (-4%, p < 0.05), also thanks to the reduction of enterocytes' susceptibility to pathogens. Finally, BOT effectively scavenged reactive oxygen species generated by inflammatory and H2O2 challenges, thus alleviating oxidative stress by 40% compared to challenge (p < 0.05). These results support the employment of BOT in piglets at weaning to help manage bacterial infections and relieve transient or prolonged stressful states thanks to the modulation of host-pathogen interaction and the fine-tuning activity on the inflammatory tone.

Dietary lysozyme improves growth performance and intestinal barrier function of weaned piglets

Lysozyme (LZ) is a purely natural, nonpolluting and nonspecific immune factor, which has beneficial effects on the healthy development of animals. In this study, the influences of LZ on the growth performance and intestinal barrier of weaned piglets were studied. A total of 48 weaned piglets (Landrace × Yorkshire, 22 d old) were randomly divided into a control group (basal diet) and a LZ group (0.1% LZ diet) for 19 d. The results showed that LZ could significantly improve the average daily gain (ADG, P < 0.05) and average daily feed intake (ADFI, P < 0.05). LZ also improved the intestinal morphology and significantly increased the expression of occludin in the jejunum (P < 0.05). In addition, LZ down-regulated the expression of interleukin-1β (IL-1β, P < 0.05) and tumor necrosis factor-α (TNF-α, P < 0.05), and inhibited the expression of the genes in the nuclear factor-k-gene binding (NF-κB, P < 0.05) signaling pathway. More importantly, the analysis of intestinal flora showed LZ increased the abundance of Firmicutes (P < 0.05) and the ratio of Firmicutes to Bacteroidota (P = 0.09) at the phylum level, and increased the abundance of Clostridium_sensu_stricto_1 (P < 0.05) and reduced the abundance of Olsenella and Prevotella (P < 0.05) at the genus level. In short, this study proved that LZ could effectively improve the growth performance, relieve inflammation and improve the intestinal barrier function of weaned piglets. These findings provided an important theoretical basis for the application of LZ in pig production.

Mechanism of Qingchang Suppository on repairing the intestinal mucosal barrier in ulcerative colitis

Ulcerative colitis (UC) is a refractory inflammatory bowel disease, and the outcomes of conventional therapies of UC, including 5-aminosalicylic acid, glucocorticoids, immunosuppressants, and biological agents, are not satisfied with patients and physicians with regard to adverse reactions and financial burden. The abnormality of the intestinal mucosal barrier in the pathogenesis of UC was verified. Qingchang Suppository (QCS) is an herbal preparation and is effective in treating ulcerative proctitis. The mechanism of QCS and its active ingredients have not been concluded especially in mucosal healing. This review elucidated the potential mechanism of QCS from the intestinal mucosal barrier perspective to help exploring future QCS research directions.

Mechanisms underlying the Effects of Heat Stress on Intestinal Integrity, Inflammation, and Microbiota in Chickens

Poultry meat and egg production benefits from a smaller carbon footprint, as well as feed and water consumption, per unit of product, than other protein sources. Therefore, maintaining a sustainable production of poultry meat is important to meet the increasing global demand for this staple. Heat stress experienced during the summer season or in tropical/subtropical areas negatively affects the productivity and health of chickens. Crucially, its impact is predicted to grow with the acceleration of global warming. Heat stress affects the physiology, metabolism, and immune response of chickens, causing electrolyte imbalance, oxidative stress, endocrine disorders, inflammation, and immunosuppression. These changes do not occur independently, pointing to a systemic mechanism. Recently, intestinal homeostasis has been identified as an important contributor to nutrient absorption and the progression of systemic inflammation. Its mechanism of action is thought to involve neuroendocrine signaling, antioxidant response, the presence of oxidants in the diet, and microbiota composition. The present review focuses on the effect of heat stress on intestinal dysfunction in chickens and the underlying causative factors. Understanding these mechanisms will direct the design of strategies to mitigate the negative effect of heat stress, while benefiting both animal health and sustainable poultry production.

Inhibition of the MLCK/MLC2 pathway protects against intestinal heat stroke-induced injury in rats

Intestinal barrier dysfunction often exists in the heat stroke (HS) pathological process, which increases intestinal permeability and induces endotoxemia. The upregulation of MLCK is a crucial player affecting intestinal permeability. This study aimed to explore whether inhibiting myosin light chain kinase (MLCK) can improve HS-induced intestinal injury in rats. Twelve-week-old Wistar male rats were divided into three groups: the control group, the HS model group, and the treatment group [HS model + ML-7 (MLCK inhibitor)]. HS impaired the tight junctions in the rat gut and increased permeability. Additionally, increased inflammatory factors in serum, activation of apoptosis, and downregulation of tight junction proteins were observed in intestinal cells. ML-7 significantly inhibited the MLCK/p-MLC2 signaling pathway, increased the expression of tight junction proteins, reduced intestinal permeability, reduced apoptosis and alleviated the intestinal damage caused by HS. ML-7 inhibited HS-induced apoptosis of intestinal epithelial cells by regulating the ERK/p38/HSP70 axis. Furthermore, inhibition of MLCK upregulated HSP70 expression through activation of the ERK pathway and inhibited cell apoptosis by abolishing the p38 MAPK pathway. In conclusion, inhibiting the MLCK/p-MLC2 signaling pathway reduces HS-induced intestinal permeability and protects the intestinal mucosal barrier.

Effect of carotenoids on gut health and inflammatory status: A systematic review of in vivo animal studies

Carotenoids have anti-inflammatory and antioxidant properties, being a potential bioactive compound for gut health. The objective of this systematic review was to investigate the effects of carotenoids on gut microbiota, gut barrier, and inflammation in healthy animals. The systematic search from PubMed, Scopus, and Lilacs databases were performed up to March 2023. The final screening included thirty studies, with different animal models (mice, rats, pigs, chicks, drosophila, fish, and shrimp), and different carotenoid sources (β-carotene, lycopene, astaxanthin, zeaxanthin, lutein, and fucoxanthin). The results suggested that carotenoids seem to act on gut microbiota by promoting beneficial effects on intestinal bacteria related to both inflammation and SCFA production; increase tight junction proteins expression, important for reducing intestinal permeability; increase the mucins expression, important in protecting against pathogens and toxins; improve morphological parameters important for digestion and absorption of nutrients; and reduce pro-inflammatory and increase anti-inflammatory cytokines. However, different carotenoids had distinct effects on gut health. In addition, there was heterogeneity between studies regarding animal model, duration of intervention, and doses used. This is the first systematic review to address the effects of carotenoids on gut health. Further studies are needed to better understand the effects of carotenoids on gut health.

TLR7/TLR8 activation and susceptibility genes synergize to breach gut barrier in a mouse model of lupus

Background

Mounting evidence suggests that increased gut permeability, or leaky gut, and the resulting translocation of pathobionts or their metabolites contributes to the pathogenesis of Systemic Lupus Erythematosus. However, the mechanisms underlying the induction of gut leakage remain unclear. In this study, we examined the effect of a treatment with a TLR7/8 agonist in the B6.Sle1.Sle2.Sle3 triple congenic (TC) mouse, a spontaneous mouse model of lupus without gut leakage.

Materials and methods

Lupus-prone mice (TC), TC.Rag1-/- mice that lack B and T cells, and congenic B6 healthy controls were treated with R848. Gut barrier integrity was assessed by measuring FITC-dextran in the serum following oral gavage. Claudin-1 and PECAM1 expression as well as the extent of CD45+ immune cells, B220+ B cells, CD3+ T cells and CD11b+ myeloid cells were measured in the ileum by immunofluorescence. NKp46+ cells were measured in the ileum and colon by immunofluorescence. Immune cells in the ileum were also analyzed by flow cytometry.

Results

R848 decreased gut barrier integrity in TC but not in congenic control B6 mice. Immunofluorescence staining of the ileum showed a reduced expression of the tight junction protein Claudin-1, endothelial cell tight junction PECAM1, as well as an increased infiltration of immune cells, including B cells and CD11b+ cells, in R848-treated TC as compared to untreated control mice. However, NKp46+ cells which play critical role in maintaining gut barrier integrity, had a lower frequency in treated TC mice. Flow cytometry showed an increased frequency of plasma cells, dendritic cells and macrophages along with a decreased frequency of NK cells in R848 treated TC mice lamina propria. In addition, we showed that the R848 treatment did not induce gut leakage in TC.Rag1-/- mice that lack mature T and B cells.

Conclusions

These results demonstrate that TLR7/8 activation induces a leaky gut in lupus-prone mice, which is mediated by adaptive immune responses. TLR7/8 activation is however not sufficient to breach gut barrier integrity in non-autoimmune mice.

A spike in circulating cytokines TNF-α and TGF-β alters barrier function between vascular and musculoskeletal tissues

Molecular transport between the circulatory and musculoskeletal systems regulates articular joint physiology in health and disease. Osteoarthritis (OA) is a degenerative joint disease linked to systemic and local inflammation. Inflammatory events involve cytokines, which are secreted by cells of the immune system and modulate molecular transport across tissue interfaces (referred to as tight junction [TJ] barrier function). In a previous study from our group, OA knee joint tissues were shown to exhibit size separation of different sized molecules delivered as a single bolus to the heart (Ngo et al. in Sci. Rep. 8:10254, 2018). Here, in a follow up study of parallel design, we test the hypothesis that two common cytokines, with multifaceted roles in the etiology of osteoarthritis as well as immune state in general, modulate the barrier function properties of joint tissue interfaces. Specifically, we probe the effect of an acute cytokine increase (spike) on molecular transport within tissues and across tissue interfaces of the circulatory and musculoskeletal systems. A single bolus of fluorescent-tagged 70 kDa dextran, was delivered intracardially, either alone, or with either the pro-inflammatory cytokine TNF-α or the anti-inflammatory cytokine TGF-β, to skeletally mature (11 to 13-month-old) guinea pigs (Dunkin-Hartley, a spontaneous OA animal model). After five minutes' circulation, whole knee joints were serial sectioned and fluorescent block face cryo-imaged at near-single-cell resolution. The 70 kDa fluorescent-tagged tracer is analogous in size to albumin, the most prevalent blood transporter protein, and quantification of tracer fluorescence intensity gave a measure of tracer concentration. Within five minutes, a spike (acute doubling) in circulating cytokines TNF-α or TGF-β significantly disrupted barrier function between the circulatory and musculoskeletal systems, with barrier function essentially abrogated in the TNF-α group. In the entire volume of the joint (including all tissue compartments and the bounding musculature), tracer concentration was significantly decreased in the TGF-β- and TNF-α- compared to the control-group. These studies implicate inflammatory cytokines as gatekeepers for molecular passage within and between tissue compartments of our joints and may open new means to delay the onset and mitigate the progression of degenerative joint diseases such as OA, using pharmaceutical and/or physical measures.

Piglet cardiopulmonary bypass induces intestinal dysbiosis and barrier dysfunction associated with systemic inflammation

The intestinal microbiome is essential to human health and homeostasis, and is implicated in the pathophysiology of disease, including congenital heart disease and cardiac surgery. Improving the microbiome and reducing inflammatory metabolites may reduce systemic inflammation following cardiac surgery with cardiopulmonary bypass (CPB) to expedite recovery post-operatively. Limited research exists in this area and identifying animal models that can replicate changes in the human intestinal microbiome after CPB is necessary. We used a piglet model of CPB with two groups, CPB (n=5) and a control group with mechanical ventilation (n=7), to evaluate changes to the microbiome, intestinal barrier dysfunction and intestinal metabolites with inflammation after CPB. We identified significant changes to the microbiome, barrier dysfunction, intestinal short-chain fatty acids and eicosanoids, and elevated cytokines in the CPB/deep hypothermic circulatory arrest group compared to the control group at just 4 h after intervention. This piglet model of CPB replicates known human changes to intestinal flora and metabolite profiles, and can be used to evaluate gut interventions aimed at reducing downstream inflammation after cardiac surgery with CPB.

Intestinal Lymphatic Dysfunction in Kidney Disease

Kidney disease is associated with adverse consequences in many organs beyond the kidney, including the heart, lungs, brain, and intestines. The kidney-intestinal cross talk involves intestinal epithelial damage, dysbiosis, and generation of uremic toxins. Recent studies reveal that kidney injury expands the intestinal lymphatics, increases lymphatic flow, and alters the composition of mesenteric lymph. The intestinal lymphatics, like blood vessels, are a route for transporting potentially harmful substances generated by the intestines. The lymphatic architecture and actions are uniquely suited to take up and transport large macromolecules, functions that differentiate them from blood vessels, allowing them to play a distinct role in a variety of physiological and pathological processes. Here, we focus on the mechanisms by which kidney diseases result in deleterious changes in intestinal lymphatics and consider a novel paradigm of a vicious cycle of detrimental organ cross talk. This concept involves kidney injury-induced modulation of intestinal lymphatics that promotes production and distribution of harmful factors, which in turn contributes to disease progression in distant organ systems.

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

BACKGROUND

Intestinal inflammation is the main risk factor causing intestinal barrier dysfunction and lipopolysaccharide (LPS) can trigger inflammatory responses in various eukaryotic species. Yeast hydrolysate (YH) possesses multi-biological effects and is received remarkable attention as a functional ingredient for improving growth performance and promoting health in animals. However, there is still inconclusive on the protective effects of dietary YH supplementation on intestinal barrier of piglets. This study was conducted to investigate the attenuate effects of YH supplementation on inflammatory responses and intestinal barrier injury in piglets challenged with LPS.

METHODS

Twenty-four piglets (with an average body weight of 7.42 ± 0.34 kg) weaned at 21 days of age were randomly assigned to one of two dietary treatments (12 replications with one pig per pen): a basal diet or a basal diet containing YH (5 g/kg). On the 22^nd d, 6 piglets in each treatment were intraperitoneally injected with LPS at 150 μg/kg BW, and the others were injected with the same amount of sterile normal saline. Four hours later, blood samples of each piglet were collected and then piglets were euthanized.

RESULTS

Dietary YH supplementation increased average daily feed intake and average daily gain (P < 0.01), decreased the ratio of feed intake to gain of piglets (P = 0.048). Lipopolysaccharide (LPS) injection induced systemic inflammatory response, evidenced by the increase of serum concentrations of haptoglobin (HP), adrenocorticotropic hormone (ACTH), cortisol, and interleukin-1β (IL-1β). Furthermore, LPS challenge resulted in inflammatory intestinal damage, by up-regulation of the protein or mRNA abundances of tumor necrosis factor-α (TNF-α), IL-1β, toll-like receptors 4 (TLR4) and phosphor-nuclear factor-κB-p65 (p-NFκB-p65) (P < 0.01), and down-regulation of the jejunal villus height, the protein and mRNA abundances of zonula occludens-1 (ZO-1) and occludin (OCC; P < 0.05) in jejunal mucosa. Dietary YH supplementation decreased the impaired effects of ACTH, cortisol, HP, IL-1β and diamine oxidase in serum (P < 0.05). Moreover, YH supplementation also up-regulated the jejunal villus height, protein and mRNA abundances of ZO-1 and OCC (P < 0.05), down-regulated the mRNA expressions of TNF-α and IL-1β and the protein abundances of TNF-α, IL-1β, TLR4 and p-NFκB-p65 in jejunal mucosa in LPS-challenged pigs (P < 0.01).

CONCLUSION

Yeast hydrolysate could attenuate inflammatory response and intestinal barrier injury in weaned piglets challenged with LPS, which was associated with the inhibition of TLR4/NF-κB signaling pathway activation.

Neutrophilic inflammation promotes SARS-CoV-2 infectivity and augments the inflammatory responses in airway epithelial cells

Introduction

In response to viral infection, neutrophils release inflammatory mediators as part of the innate immune response, contributing to pathogen clearance through virus internalization and killing. Pre- existing co-morbidities correlating to incidence to severe COVID-19 are associated with chronic airway neutrophilia. Furthermore, examination of COVID-19 explanted lung tissue revealed a series of epithelial pathologies associated with the infiltration and activation of neutrophils, indicating neutrophil activity in response to SARS-CoV-2 infection.

Methods

To determine the impact of neutrophil-epithelial interactions on the infectivity and inflammatory responses to SARS-CoV-2 infection, we developed a co-culture model of airway neutrophilia. This model was infected with live SARS-CoV-2 virus the epithelial response to infection was evaluated.

Results

SARS-CoV-2 infection of airway epithelium alone does not result in a notable pro-inflammatory response from the epithelium. The addition of neutrophils induces the release of proinflammatory cytokines and stimulates a significantly augmented proinflammatory response subsequent SARS-CoV-2 infection. The resulting inflammatory responses are polarized with differential release from the apical and basolateral side of the epithelium. Additionally, the integrity of the \epithelial barrier is impaired with notable epithelial damage and infection of basal stem cells.

Conclusions

This study reveals a key role for neutrophil-epithelial interactions in determining inflammation and infectivity.

The role of mir-197-3p in regulating the tight junction permeability of celiac disease patients under gluten free diet

BACKGROUND

Celiac disease (CD) is a hereditary immune-mediated disorder, which is along with the enormous production of pro-inflammatory cytokines and the reduced level of tight junction proteins. The aim of this study was to determine the expression of TNF-α, IFN-γ, IL-18, Occludin, miR-122-5p and miR-197-3p genes in duodenal biopsies of treated CD patients in comparison to the controls.

METHODS AND RESULTS

Biopsy specimens were taken from the duodenum of 50 treated CD patients (36 (72%) females and 14 (28%) males with mean age of 37.06 ± 7.02 years) and 50 healthy controls (17 (34%) females and 33 (66%) males with mean age of 34.12 ± 4.9). Total RNA was isolated, cDNA was synthesized and mRNA expression of TNF-α, IFN-γ, IL-18, Occludin, miR-122-5p and miR-197-3p were quantified by relative qPCR using B2M and U6 as internal control genes. All data were evaluated using SPSS (V.21) and GraphPad Prism (V.5). Our results showed that there was no significant difference between patients and controls for intestinal mRNA expression of TNF-α, IFN-γ, IL-18, Occludin, and miR-122-5p (p > 0.05) and the expression of miR-197-3p was significantly increased in CD patients relative to control subjects (p = 0.049).

CONCLUSION

This study suggests that adherence to GFD may have a positive effect on the tight junction (TJ) permeability and in this process, miR-197-3p plays an important role. Increased expression of miR-197-3p with a final protective effect on Occludin expression can be further studied as a complement therapeutic target for Celiac disease.

Effects of microencapsulated blend of organic acids and botanicals on growth performance, intestinal barrier function, inflammatory cytokines, and endocannabinoid system gene expression in broiler chickens

With restricted usage of growth-promoting antibiotics, identifying alternative feed additives that both improve intestinal barrier function and reduce inflammation is the center to improve chickens' health. This study examined the effects of a microencapsulated feed additive containing citric acid, sorbic acids, thymol, and vanillin on intestinal barrier function and inflammation status. A total of 240 birds were assigned to either a commercial control diet or control diet supplemented with 500 g/MT of the microencapsulated additive product. Birds were raised by feeding a 2-phase diet (starter, d 1 to d 21; and grower, d 15 to d 42). Growth performance was recorded weekly. At d 21 and d 42, total gastrointestinal tract permeability was evaluated by FITC-dextran (FD4) oral gavage. Jejunum-specific barrier functions were evaluated by Ussing chamber. Intestinal gene expression of selected epithelial cell markers, tight junction (TJ) proteins, inflammatory cytokines, and endocannabinoid system (ECS) markers were determined by RT-PCR. Statistical analysis was performed using Student t test. Results showed significant improvement of feed efficiency in the birds supplemented with the blend of organic acids and botanicals. At d 21, both oral and jejunal FD4 permeability were lower in the supplemented group. Jejunal transepithelial resistance was higher in the supplemented birds. At d 21, expression of TJs mRNA (CLDN1 and ZO2) was both upregulated in the jejunum and ileum of supplemented birds, while CLDN2 was downregulated in cecum. Proliferating cell marker SOX9 was higher expressed in jejunum and ceca. Goblet cell marker (MUC2) was upregulated, while Paneth cell marker (LYZ) was downregulated in the ileum. Proinflammatory cytokine expressions of IL1B, TNFA, and IFNG were downregulated in jejunum, while anti-inflammatory IL10 expression was higher in jejunum, ileum, cecum, and cecal tonsil. The ECS markers expressions were upregulated in most intestinal regions. Together, these results demonstrated that the blend of organic acids and botanical supplementation reduced inflammation, improved the TJs expression and intestinal barrier function, and thus improved chicken feed efficiency. The activated ECS may play a role in reducing intestinal tissue inflammation.

Administration of Bifidobacterium pseudolongum suppresses the increase of colonic serotonin and alleviates symptoms in dextran sodium sulfate-induced colitis in mice

Previous studies suggested that altered gut serotonin (5-HT) signaling is implicated in the pathophysiology of inflammatory bowel disease (IBD). Indeed, 5-HT administration reportedly exacerbated the severity of murine dextran sodium sulfate (DSS)-induced colitis that mimics human IBD. Our recent study suggested that Bifidobacterium pseudolongum, one of the most predominant bifidobacterial species in various mammals, reduces the colonic 5-HT content in mice. The present study thus tested whether the administration of B. pseudolongum prevents DSS-induced colitis in mice. Colitis was induced by administering 3% DSS in drinking water in female BALB/c mice, and B. pseudolongum (10⁹ CFU/day) or 5-aminosalicylic acid (5-ASA, 200 mg/kg body weight) was intragastrically administered once daily throughout the experimental period. B. pseudolongum administration reduced body weight loss, diarrhea, fecal bleeding, colon shortening, spleen enlargement, and colon tissue damage and increased colonic mRNA levels of cytokine genes (Il1b, Il6, Il10, and Tnf) almost to an extent similar to 5-ASA administration in DSS-treated mice. B. pseudolongum administration also reduced the increase of colonic 5-HT content, whereas it did not alter the colonic mRNA levels of genes that encode the 5-HT synthesizing enzyme, 5-HT reuptake transporter, 5-HT metabolizing enzyme, and tight junction-associated proteins. We propose that B. pseudolongum is as beneficial against murine DSS-induced colitis as the widely used anti-inflammatory agent 5-ASA. However, further studies are needed to clarify the causal relationship between the reduced colonic 5-HT content and reduced severity of DSS-induced colitis caused by B. pseudolongum administration.

Dietary nucleotides influences intestinal barrier function, immune responses and microbiota in 3-day-old weaned piglets

Nucleotides (NTs) play a pivotal role in the growth and development of the intestine. This study aimed to evaluate the effects of nucleotides supplementation on the intestinal barrier function, immune responses and microbiota in 3-day-old weaned piglets. Ninety-six piglets weaned at 3-days after birth were randomly assigned to 2 treatments (6 replicates/treatment, 8 piglets/replicate) according to the average body weight. The dietary treatments consisted of the control (CON; fed a basal artificial milk) and nucleotides groups (NT; fed a basal artificial milk with 0.035 % nucleotides, the contents of CMP, UMP, AMP, GMP, and IMP were 1:1:1:1:1, respectively). Diarrhea rates were recorded, and blood and intestinal samples were collected on day 35 of the piglets. The current study showed that NTs supplementation tended to decrease the diarrhea rate of weaned piglets (P < 0.10). NTs increased villus height and the villus height-to-crypt depth (V/C) ratio in the ileum (P < 0.05). Dietary NTs up-regulated protein expression of ZO-1 in ileal mucosa (P < 0.05), and the protein expression of Occludin tended to increase. Furthermore, NTs up-regulated the mRNA expression of Mucin (MUC)2, while the mRNA expression of MUC4 was down-regulated in the ileal mucosa (P < 0.05). Besides, supplementation with NTs increased the ileal mucosa genes expression of IL-21, INF-γ, IL-10, IL-4, IL-6 and TNF-α (P < 0.05). Furthermore, dietary NTs increased the protein expression of NF-κB, IL-6 and TNF-α (P < 0.05), and the proteins expression of Occludin and p-NF-κB tended to be up-regulated in the ileal mucosa (P < 0.10). Furthermore, NTs supplementation increased short chain fatty acid in the colonic (P < 0.05). And NTs supplementation reduced the Firmicutes/Bacteroidota ratio in the colon, at the genus level, NTs enriched the relative abundance of Prevotella, Faecalibacterium and Olsenella (P < 0.05). These data indicate that NTs could increase the villus height, increase the V/C, regulate the expression of tight junction protein and mucin, improve the intestinal barrier of piglets, regulate the secretion of cytokines, improve the biological immunity, increase the abundance of beneficial bacteria, and thus reduce the diarrhea of piglets.

Tanshinone IIA-loaded nanoparticles and neural stem cell combination therapy improves gut homeostasis and recovery in a pig ischemic stroke model

Impaired gut homeostasis is associated with stroke often presenting with leaky gut syndrome and increased gut, brain, and systemic inflammation that further exacerbates brain damage. We previously reported that intracisternal administration of Tanshinone IIA-loaded nanoparticles (Tan IIA-NPs) and transplantation of induced pluripotent stem cell-derived neural stem cells (iNSCs) led to enhanced neuroprotective and regenerative activity and improved recovery in a pig stroke model. We hypothesized that Tan IIA-NP + iNSC combination therapy-mediated stroke recovery may also have an impact on gut inflammation and integrity in the stroke pigs. Ischemic stroke was induced, and male Yucatan pigs received PBS + PBS (Control, n = 6) or Tan IIA-NP + iNSC (Treatment, n = 6) treatment. The Tan IIA-NP + iNSC treatment reduced expression of jejunal TNF-α, TNF-α receptor1, and phosphorylated IkBα while increasing the expression of jejunal occludin, claudin1, and ZO-1 at 12 weeks post-treatment (PT). Treated pigs had higher fecal short-chain fatty acid (SCFAs) levels than their counterparts throughout the study period, and fecal SCFAs levels were negatively correlated with jejunal inflammation. Interestingly, fecal SCFAs levels were also negatively correlated with brain lesion volume and midline shift at 12 weeks PT. Collectively, the anti-inflammatory and neuroregenerative treatment resulted in increased SCFAs levels, tight junction protein expression, and decreased inflammation in the gut.

Gut epithelial barrier damage caused by dishwasher detergents and rinse aids

BACKGROUND

The increased prevalence of many chronic inflammatory diseases linked to gut epithelial barrier leakiness has prompted us to investigate the role of extensive use of dishwasher detergents, among other factors.

OBJECTIVE

We sought to investigate the effects of professional and household dishwashers, and rinse agents, on cytotoxicity, barrier function, transcriptome, and protein expression in gastrointestinal epithelial cells.

METHODS

Enterocytic liquid-liquid interfaces were established on permeable supports, and direct cellular cytotoxicity, transepithelial electrical resistance, paracellular flux, immunofluorescence staining, RNA-sequencing transcriptome, and targeted proteomics were performed.

RESULTS

The observed detergent toxicity was attributed to exposure to rinse aid in a dose-dependent manner up to 1:20,000 v/v dilution. A disrupted epithelial barrier, particularly by rinse aid, was observed in liquid-liquid interface cultures, organoids, and gut-on-a-chip, demonstrating decreased transepithelial electrical resistance, increased paracellular flux, and irregular and heterogeneous tight junction immunostaining. When individual components of the rinse aid were investigated separately, alcohol ethoxylates elicited a strong toxic and barrier-damaging effect. RNA-sequencing transcriptome and proteomics data revealed upregulation in cell death, signaling and communication, development, metabolism, proliferation, and immune and inflammatory responses of epithelial cells. Interestingly, detergent residue from professional dishwashers demonstrated the remnant of a significant amount of cytotoxic and epithelial barrier-damaging rinse aid remaining on washed and ready-to-use dishware.

CONCLUSIONS

The expression of genes involved in cell survival, epithelial barrier, cytokine signaling, and metabolism was altered by rinse aid in concentrations used in professional dishwashers. The alcohol ethoxylates present in the rinse aid were identified as the culprit component causing the epithelial inflammation and barrier damage.

Oral Exposure to Polystyrene Microplastics of Mice on a Normal or High-Fat Diet and Intestinal and Metabolic Outcomes

BACKGROUND

Microplastics (MPs) are small particles of plastic (≤5mm in diameter). In recent years, oral exposure to MPs in living organisms has been a cause of concern. Leaky gut syndrome (LGS), associated with a high-fat diet (HFD) in mice, can increase the entry of foreign substances into the body through the intestinal mucosa.

OBJECTIVES

We aimed to evaluate the pathophysiology of intestinal outcomes associated with consuming a high-fat diet and simultaneous intake of MPs, focusing on endocrine and metabolic systems.

METHODS

C57BL6/J mice were fed a normal diet (ND) or HFD with or without polystyrene MP for 4 wk to investigate differences in glucose tolerance, intestinal permeability, gut microbiota, as well as metabolites in serum, feces, and liver.

RESULTS

In comparison with HFD mice, mice fed the HFD with MPs had higher blood glucose, serum lipid concentrations, and nonalcoholic fatty liver disease (NAFLD) activity scores. Permeability and goblet cell count of the small intestine (SI) in HFD-fed mice were higher and lower, respectively, than in ND-fed mice. There was no obvious difference in the number of inflammatory cells in the SI lamina propria between mice fed the ND and mice fed the ND with MP, but there were more inflammatory cells and fewer anti-inflammatory cells in mice fed the HFD with MPs in comparison with mice fed the HFD without MPs. The expression of genes related to inflammation, long-chain fatty acid transporter, and Na+/glucose cotransporter was significantly higher in mice fed the HFD with MPs than in mice fed the HFD without MPs. Furthermore, the genus Desulfovibrio was significantly more abundant in the intestines of mice fed the HFD with MPs in comparison with mice fed the HFD without MPs. Muc2 gene expression was decreased when palmitic acid and microplastics were added to the murine intestinal epithelial cell line MODE-K cells, and Muc2 gene expression was increased when IL-22 was added.

DISCUSSION

Our findings suggest that in this study, MP induced metabolic disturbances, such as diabetes and NAFLD, only in mice fed a high-fat diet. These findings suggest that LGS might have been triggered by HFD, causing MPs to be deposited in the intestinal mucosa, resulting in inflammation of the intestinal mucosal intrinsic layer and thereby altering nutrient absorption. These results highlight the need for reducing oral exposure to MPs through remedial environmental measures to improve metabolic disturbance under high-fat diet conditions. https://doi.org/10.1289/EHP11072.

Piceatannol and 3'-Hydroxypterostilbene Alleviate Inflammatory Bowel Disease by Maintaining Intestinal Epithelial Integrity and Regulating Gut Microbiota in Mice

Inflammatory bowel disease has become a significant health concern across the globe, causing frequent and long-term harm to the digestive system. This study evaluated the effect of piceatannol (PIC) and 3'-hydroxypterostilbene (HPSB) on dextran sulfate sodium (DSS)-induced colitis in mice and investigated whether their effects are exerted through the amelioration of gut barrier dysfunction to reduce the severity of colitis. The findings showed that both PIC and HPSB attenuated inflammation by inhibiting the TNF-α/NF-κB/MLC pathway and reducing NLRP3 inflammasome activation. However, PIC was comparably effective in modulating tight junctions. The results may be attributed to the effect of PIC on reducing cell apoptosis-associated protein expression, including Bax/Bcl-2 and caspase-3 activation. Furthermore, microbiota analysis revealed that both PIC and HPSB increased representative probiotic species, including Akkermansiaceae and Lactobacillus intestinalis, and exhibited inhibitory effects on several bacterial species (Spiroplasmataceae and Acholeplasmataceae). Based on linear discriminant analysis effect size, butyrate-producing bacteria were identified as a biomarker in the PIC group. Overall, the results demonstrated that PIC repressed inflammation, inhibited cell apoptosis, and regulated microbiota composition. Consequently, PIC is more effective in maintaining gut barrier integrity than HPSB, and it is a promising ingredient in the development of functional food for colitis prevention.

Cardiovascular Disease and Thrombosis in HIV Infection

HIV infection has transitioned from an acute, fatal disease to a chronic one managed by antiretroviral therapy. Thus, the aging population of people living with HIV (PLWH) continues to expand. HIV infection results in a dysregulated immune system, wherein CD4+ T cells are depleted, particularly in the gastrointestinal tract, disrupting the gut epithelial barrier. Long-term HIV infection is associated with chronic inflammation through potentially direct mechanisms caused by viral replication or exposure to viral proteins and indirect mechanisms resulting from increased translocation of microbial products from the intestine or exposure to antiretroviral therapy. Chronic inflammation (as marked by IL [interleukin]-6 and CRP [C-reactive protein]) in PLWH promotes endothelial cell dysfunction and atherosclerosis. PLWH show significantly increased rates of cardiovascular disease, such as myocardial infarction (risk ratio, 1.79 [95% CI, 1.54-2.08]) and stroke (risk ratio, 2.56 [95% CI, 1.43-4.61]). In addition, PLWH have increased levels of the coagulation biomarker D-dimer and have a two to ten-fold increased risk of venous thromboembolism compared with the general population. Several small clinical trials analyzed the effect of different antithrombotic agents on platelet activation, coagulation, inflammation, and immune cell activation. Although some markers for coagulation were reduced, most agents failed to reduce inflammatory markers in PLWH. More studies are needed to understand the underlying mechanisms driving inflammation in PLWH to create better therapies for lowering chronic inflammation in PLWH. Such therapies can potentially reduce atherosclerosis, cardiovascular disease, and thrombosis rates in PLWH and thus overall mortality in this population.