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

Narirutin mitigates dextrose sodium sulfate-induced colitis in mice by modulating intestinal flora

BACKGROUND

Ulcerative colitis (UC) is a prolonged inflammatory disease of the gastrointestinal tract. Current therapeutic options remain limited, underscoring the imperative to explore novel therapeutic strategies. Narirutin (NR), a flavonoid naturally present in citrus fruits, exhibits excellent anti-inflammatory effects in vitro, yet its in vivo efficacy, especially in UC, remains underexplored.

OBJECTIVE

This work examined the effect of NR on dextrose sodium sulfate (DSS)-induced UC in mice in vivo, with a specific focus on the role of gut flora in it.

METHODS

The effects of NR (10, 20, and 40 mg/kg) on DSS-induced UC in mice were investigated by monitoring changes in body weight, disease activity index (DAI) scores, colon length, and histological damage. Colonic levels of pro-inflammatory mediators, tight junction (TJ) proteins, and inflammation-related signaling pathway proteins were analyzed via enzyme-linked immunosorbent assay, western blot, and immunofluorescence. The role of gut microbiota in NR against colitis was analyzed through 16S rRNA sequencing, flora clearance assays, and fecal microbiota transplantation (FMT) assays.

RESULTS

NR administration suppressed DSS-induced colitis as reflected in a decrease in body weight loss, DAI score, colon length shortening, and histological score. Furthermore, NR administration preserved the integrity of the DSS-induced intestinal barrier by inhibiting the reduction of TJ proteins (claudin3, occludin, and zonula occludens-1). Moreover, NR administration markedly repressed the activation of the toll-like receptor 4-mitogen-activated protein kinase/nuclear factor-κB pathway and reduced the amount of pro-inflammatory mediators in the colon. Importantly, the results of 16S rRNA sequencing showed that the intestinal flora of mice with colitis exhibited richer microbial diversity following NR administration, with elevated abundance of Lactobacillaceae (Lactobacillus) and decreased abundance of Bacteroidaceae (Bacteroides) and Shigella. In addition, the anti-colitis effect of NR almost disappeared after gut flora clearance. Further FMT assay also validated this gut flora-dependent protective mechanism of NR.

CONCLUSION

Our findings suggest that NR is a prospective natural compound for the management of UC by modulating intestinal flora.

Protective effect of zinc gluconate on intestinal mucosal barrier injury in antibiotics and LPS-induced mice

Objective

The aim of the study is to investigate the function and mechanism of Zinc Gluconate (ZG) on intestinal mucosal barrier damage in antibiotics and Lipopolysaccharide (LPS)-induced mice.

Methods

We established a composite mouse model by inducing intestinal mucosal barrier damage using antibiotics and LPS. The animals were divided into five groups: Control (normal and model) and experimental (low, medium, and high-dose ZG treatments). We evaluated the intestinal mucosal barrier using various methods, including monitoring body weight and fecal changes, assessing pathological damage and ultrastructure of the mouse ileum, analyzing expression levels of tight junction (TJ)-related proteins and genes, confirming the TLR4/NF-κB signaling pathway, and examining the structure of the intestinal flora.

Results

In mice, the dual induction of antibiotics and LPS led to weight loss, fecal abnormalities, disruption of ileocecal mucosal structure, increased intestinal barrier permeability, and disorganization of the microbiota structure. ZG restored body weight, alleviated diarrheal symptoms and pathological damage, and maintained the structural integrity of intestinal epithelial cells (IECs). Additionally, ZG reduced intestinal mucosal permeability by upregulating TJ-associated proteins (ZO-1, Occludin, Claudin-1, and JAM-A) and downregulating MLCK, thereby repairing intestinal mucosal barrier damage induced by dual induction of antibiotics and LPS. Moreover, ZG suppressed the TLR4/NF-κB signaling pathway, demonstrating anti-inflammatory properties and preserving barrier integrity. Furthermore, ZG restored gut microbiota diversity and richness, evidenced by increased Shannon and Observed features indices, and decreased Simpson's index. ZG also modulated the relative abundance of beneficial human gut bacteria (Bacteroidetes, Firmicutes, Verrucomicrobia, Parabacteroides, Lactobacillus, and Akkermansia) and harmful bacteria (Proteobacteria and Enterobacter), repairing the damage induced by dual administration of antibiotics and LPS.

Conclusion

ZG attenuates the dual induction of antibiotics and LPS-induced intestinal barrier damage and also protects the intestinal barrier function in mice.

Vitamin A deficiency suppresses CEACAM1 to impair colonic epithelial barrier function via downregulating microbial-derived short-chain fatty acids

Vitamin A (VA) plays an essential role in modulating both the gut microbiota and gut barrier function. Short-chain fatty acids (SCFAs), as metabolites of the gut microbiota, protect the physiological intestinal barrier; however, they are compromised when VA is deficient. Thus, there is an urgent need to understand how and which SCFAs modulate colonic epithelial barrier integrity in VA deficiency (VAD). Herein, compared with normal VA rats (VAN), at the beginning of pregnancy, we confirmed that the colonic desmosome junction was impaired in the VAD group, and the amounts of acetate, propionate, and butyrate declined because of the decreased abundance of SCFA-producing bacteria (Romboutsia, Collinsella, and Allobaculum). The differentially expressed genes correlated with the gut barrier and the histone deacetylase complex between the VAD and VAN groups were enriched by RNA sequencing. In the VAD group, the expression levels of colonic CEA cell adhesion molecule 1 (CEACAM1) were down-regulated, and the levels of histone deacetylase 1 (HDAC1) and HDAC3 were up-regulated. Intriguingly, the above changes in the VAD groups were rescued by VA supplementation in the early postnatal period. Further study indicated that in Caco-2 cells, butyrate treatment significantly repressed the enrichment of HDAC3 on the promoter of the CEACAM1 gene to induce its expression. Our findings support that butyrate intervention can alleviate the impairment of colonic barrier function caused by VAD, and timely postnatal VA intervention may reverse the damage caused by VAD on gut barrier integrity during pregnancy.

Impacts of pyraclostrobin on intestinal health and the intestinal microbiota in common carp (Cyprinus carpio L.)

Pyraclostrobin (PYR) is a strobilurin fungicide that is commonly used in agriculture, and its use in agriculture may lead to an increase in its residue in the aquatic environment and may have a deleterious influence on the intestinal health of aquatic creatures. Here, common carp were chronically exposed to PYR (0, 0.5, or 5.0 μg/L) for 30 d to determine its effect on the physical and immunological barrier and intestinal microbiota in the intestine. PYR exposure caused significant histological changes; altered the mRNA expression levels of occludin, claudin-2, and zonula occludens-1 (ZO-1); induced oxidative stress in the common carp intestine; and increased the serum D-lactate and diamine oxidase (DAO) levels. Moreover, PYR significantly increased the protein expression levels of tumour necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and IL-6 while decreasing the level of transforming growth factor beta (TGF-β). Further studies revealed that PYR significantly reduced lysozyme (LZM) and acid phosphatase (ACP) activities as well as complement 3 (C3) and immunoglobulin M (IgM) levels. Furthermore, PYR decreased gut microbial diversity while increasing the abundance of pathogenic bacteria such as Aeromonas and Shewanella, causing an intestinal microbial disturbances in common carp. These results imply that PYR has a negative impact on fish intestinal health and may pose serious health risks to fish by disrupting the intestinal microbiota, physical barrier, and immunological barrier in common carp.

Effects of Electrolyte Multivitamins and Neomycin on Immunity and Intestinal Barrier Function in Transported Lambs

Animals experience stress when they are transported. In this experiment, sixty 4-month-old lambs were randomly divided into three groups: CG (basal diet), EG (basal diet + 375 mg/d/lamb electrolytic multivitamin) and NG (basal diet + 200 mg/d/lamb neomycin). The transportation day was recorded as the 0th day. Blood, liver, spleen, jejunum and colon were collected on the 0th, 7th and 14th day. The results were as follows: In EG and NG groups, the lamb weights (p < 0.01), IgA and IgG (p < 0.05) increased significantly. The concentrations of ACTH, E, COR, IL-1β, IL-6 and IFN-γ decreased significantly (p < 0.01). The content of colonic propionate increased significantly (p < 0.05). The villus height and V/C increased, and crypt depth decreased significantly (p < 0.01). The mRNA expressions of Occludin and MUC1, and the protein expression of Occludin in the jejunal mucosa, the mRNA expressions of ZO-1 and Occludin, and the protein expression in the colonic mucosa increased significantly (p < 0.01). The mRNA expression of TRAF6 and the protein expression of TLR4 in the jejunum decreased significantly (p < 0.05), as well as the mRNA expressions of TLR4, MyD88 and NF-kB, and the protein expression of NF-kB p65 and the mRNA expressions of TRAF6, TLR4 and NF-kB in the colon (p < 0.01). In conclusion, an electrolytic multivitamin could potentially improve the immunity and intestinal barrier function, and when it was added with 375 mg/d in the basal diet for each lamb from 2 d before transportation to 7 d after transportation, it had a better effect than neomycin.

The Role and Mechanism of Retinol and Its Transformation Product, Retinoic Acid, in Modulating Oxidative Stress-Induced Damage to the Duck Intestinal Epithelial Barrier In Vitro

This study aimed to investigate the effects and mechanisms of retinol and retinoic acid on primary duck intestinal epithelial cells under oxidative stress induced by H2O2. Different ratios of retinol and retinoic acid were used for treatment. The study evaluated the cell morphology, viability, antioxidative capacity, and barrier function of cells. The expression of genes related to oxidative stress and the intestinal barrier was analyzed. The main findings demonstrated that the treated duck intestinal epithelial cells exhibited increased viability, increased antioxidative capacity, and improved intestinal barrier function compared to the control group. High retinoic acid treatment improved viability and gene expression, while high retinol increased antioxidative indicators and promoted intestinal barrier repair. Transcriptome analysis revealed the effects of treatments on cytokine interactions, retinol metabolism, PPAR signaling, and cell adhesion. In conclusion, this study highlights the potential of retinol and retinoic acid in protecting and improving intestinal cell health under oxidative stress, providing valuable insights for future research.

Specific Milk Composition of miR-30b Transgenic Mice Associated with Early Duodenum Maturation in Offspring with Lasting Consequences for Growth

BACKGROUND

Milk composition is complex and includes numerous components essential for offspring growth and development. In addition to the high abundance of miR-30b microRNA, milk produced by the transgenic mouse model of miR-30b-mammary deregulation displays a significantly altered fatty acid profile. Moreover, wild-type adopted pups fed miR-30b milk present an early growth defect.

OBJECTIVE

This study aimed to investigate the consequences of miR-30b milk feeding on the duodenal development of wild-type neonates, a prime target of suckled milk, along with comprehensive milk phenotyping.

METHODS

The duodenums of wild-type pups fed miR-30b milk were extensively characterized at postnatal day (PND)-5, PND-6, and PND-15 using histological, transcriptomic, proteomic, and duodenal permeability analyses and compared with those of pups fed wild-type milk. Milk of miR-30b foster dams collected at mid-lactation was extensively analyzed using proteomic, metabolomic, and lipidomic approaches and hormonal immunoassays.

RESULTS

At PND-5, wild-type pups fed miR-30b milk showed maturation of their duodenum with 1.5-fold (P < 0.05) and 1.3-fold (P < 0.10) increased expression of Claudin-3 and Claudin-4, respectively, and changes in 8 duodenal proteins (P < 0.10), with an earlier reduction in paracellular and transcellular permeability (183 ng/mL fluorescein sulfonic acid [FSA] and 12 ng/mL horseradish peroxidase [HRP], respectively, compared with 5700 ng/mL FSA and 90 ng/mL HRP in wild-type; P < 0.001). Compared with wild-type milk, miR-30b milk displayed an increase in total lipid (219 g/L compared with 151 g/L; P < 0.05), ceramide (17.6 μM compared with 6.9 μM; P < 0.05), and sphingomyelin concentrations (163.7 μM compared with 76.3 μM; P < 0.05); overexpression of 9 proteins involved in the gut barrier (P < 0.1); and higher insulin and leptin concentrations (1.88 ng/mL and 2.04 ng/mL, respectively, compared with 0.79 ng/mL and 1.06 ng/mL; P < 0.01).

CONCLUSIONS

miR-30b milk displays significant changes in bioactive components associated with neonatal duodenal integrity and maturation, which could be involved in the earlier intestinal closure phenotype of the wild-type pups associated with a lower growth rate.

Vitamin A deficiency from maternal gestation may contribute to autistic-like behaviors and gastrointestinal dysfunction in rats through the disrupted purine and tryptophan metabolism

Vitamin A deficiency (VAD) has been linked to autism spectrum disorder (ASD) in multiple studies, and autistic children with gastrointestinal (GI) symptoms have been found to have lower VA levels than those without GI symptoms. However, the exact mechanism by which VAD causes both core symptoms and GI symptoms in ASD is ill defined. We constructed VAD and vitamin A normal (VAN) rat models from maternal gestation onwards. Autism-related behaviors were tested using the open-field test and the three-chamber test, and GI function was assessed with the GI transit time, the colonic transit time and fecal water content. Untargeted metabolomic analysis on the prefrontal cortex (PFC) and fecal samples was performed. VAD rats displayed autistic-like behaviors and impaired GI function compared to VAN rats. Metabolic profiles of both PFC and feces from VAD and VAN rats were significantly different. The differential metabolites in both PFC and feces between the VAN and VAD rats were mostly enriched in the purine metabolic pathway. Moreover, the most significantly affected metabolic pathway in PFC of VAD rats was the phenylalanine, tyrosine and tryptophan biosynthesis pathway, and the most remarkably altered metabolic pathway in the feces of VAD rats was the tryptophan metabolism pathway. These results indicate that VAD starting from maternal gestation might be linked to core symptoms of ASD and its GI co-occurring disorders through the purine and tryptophan-related metabolism disorders.

The association of vitamin A, zinc and copper levels with clinical symptoms in children with autism spectrum disorders in Jilin Province, China

BACKGROUND

This study evaluated vitamin A (VA), copper (Cu), and zinc (Zn) levels in the population with autism spectrum disorder (ASD) in Jilin Province, China. Furthermore, we examined their links to core symptoms and neurodevelopment, as well as gastrointestinal (GI) comorbidities and sleep disorders.

METHODS

This study included 181 children with autism and 205 typically developing (TD) children. The participants had not taken vitamin/mineral supplements in the prior three months. High-performance liquid chromatography was used to measure serum VA levels. By using inductively coupled plasma-mass spectrometry, Zn and Cu concentrations in plasma were determined. Importantly, the Childhood Autism Rating Scale, the Social Responsiveness Scale, and the Autism Behavior Checklist were used to measure core ASD symptoms. However, the Griffith Mental Development Scales-Chinese were used to measure neurodevelopment. GI comorbidities and sleep abnormalities were assessed with the 6 Item-Gastrointestinal Severity Index and Children's Sleep Habits Questionnaire, respectively. Children with ASD with GI issues were grouped according to severity (low GI severity and high GI severity groups).

RESULTS

(i) The difference in VA, Zn, Cu levels and the Zn/Cu ratio between ASD and TD children is small. But children with ASD had lower VA levels and Zn/Cu ratio, higher Cu levels than TD children. Cu levels in children with ASD were associated with the severity of core symptoms. (ii) Children with ASD were much more likely than their TD counterparts to suffer from GI comorbidities or sleep problems. Furthermore, it was observed that high GI severity was associated with lower levels of VA, whereas low GI severity was associated with higher levels of VA. (iii) The children with ASD who had both lower VA and lower Zn/Cu ratio had more severe scores on the Autism Behavior Checklist, but not on other measures.

CONCLUSION

Children with ASD had lower VA and Zn/Cu ratio, and higher Cu levels. Cu levels in children with ASD were weakly correlated with one subscale on social or self-help. ASD children with lower VA levels may face more serious GI comorbidities. Children with ASD combined VA-Zn/Cu lower had more severe core symptoms.

TRIAL REGISTRATION

Registration number: ChiCTR-OPC-17013502. Date of registration: 2017-11-23.

The roles of dietary lipids and lipidomics in gut-brain axis in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), one of the main types of Noncommunicable diseases (NCDs), is a systemic inflammatory disease characterized by dysfunctional pancreatic β-cells and/or peripheral insulin resistance, resulting in impaired glucose and lipid metabolism. Genetic, metabolic, multiple lifestyle, and sociodemographic factors are known as related to high T2DM risk. Dietary lipids and lipid metabolism are significant metabolic modulators in T2DM and T2DM-related complications. Besides, accumulated evidence suggests that altered gut microbiota which plays an important role in the metabolic health of the host contributes significantly to T2DM involving impaired or improved glucose and lipid metabolism. At this point, dietary lipids may affect host physiology and health via interaction with the gut microbiota. Besides, increasing evidence in the literature suggests that lipidomics as novel parameters detected with holistic analytical techniques have important roles in the pathogenesis and progression of T2DM, through various mechanisms of action including gut-brain axis modulation. A better understanding of the roles of some nutrients and lipidomics in T2DM through gut microbiota interactions will help develop new strategies for the prevention and treatment of T2DM. However, this issue has not yet been entirely discussed in the literature. The present review provides up-to-date knowledge on the roles of dietary lipids and lipidomics in gut-brain axis in T2DM and some nutritional strategies in T2DM considering lipids- lipidomics and gut microbiota interactions are given.

Size-Dependent Uptake and Depuration of Nanoplastics in Tilapia (Oreochromis niloticus) and Distinct Intestinal Impacts

Nanoplastics (NPs, <1 μm) are of great concern worldwide because of their high potential risk toward organisms in aquatic systems, while very little work has been focused on their tissue-specific toxicokinetics due to the limitations of NP quantification for such a purpose. In this study, NPs with two different sizes (86 and 185 nm) were doped with palladium (Pd) to accurately determine the uptake and depuration kinetics in various tissues (intestine, stomach, liver, gill, and muscle) of tilapia (Oreochromis niloticus) in water, and subsequently, the corresponding toxic effects in the intestine were explored. Our results revealed uptake and depuration constants of 2.70-378 L kg^-1 day^-1 and 0.138-0.407 day^-1 for NPs in tilapia for the first time, and the NPs in tissues were found to be highly dependent on the particle size. The intestine exhibited the greatest relative accumulation of both sizes of NPs; the smaller NPs caused more severe damage than the larger NPs to the intestinal mucosal layer, while the larger NPs induced a greater impact on microbiota composition. The findings of this work explicitly indicate the size-dependent toxicokinetics and intestinal toxicity pathways of NPs, providing new insights into the ecological effects of NPs on aquatic organisms.

The role of vitamin A and zinc supplementation in pediatric pneumonia: A protocol for systematic review and network meta-analysis

BACKGROUND

There is still controversy regarding the role of zinc and vitamin A supplementation in pediatric pneumonia. Therefore, we designed a systematic review and network meta-analysis to incorporate the available evidence to determine the role of vitamin A and zinc in pediatric pneumonia.

METHODS

From the inception to December 31, 2022, the Web of Science, EMBASE, Medicine, the Cochrane Central Register of Controlled Trials and Cochrane Library electronic databases were searched using the key phrases "pneumonia," "pediatric," "zinc," "vitamin A," and "cohort" for all relevant studies. Cohort studies assessing the efficacy and safety of zinc and/or vitamin A supplementation in children with pneumonia will be included for quantitative or qualitative analysis. Non-cohort studies and studies that do not meet the inclusion criteria will be excluded. Outcome measures include reduction in duration of pneumonia, adverse drug events, length of hospital stay, amount of antibiotics used, and radiological parameters. The primary outcome is the degree of reduction in the duration of pneumonia.

RESULTS

This Bayesian network meta-analysis will be conducted in accordance with the PRISMA extension statement, which is used to report systematic reviews that incorporated a meta-analysis of medical intervention networks.

Orally Administered Ginkgolide C Attenuates DSS-Induced Colitis by Maintaining Gut Barrier Integrity, Inhibiting Inflammatory Responses, and Regulating Intestinal Flora

Ulcerative colitis (UC), one of the foremost common forms of inflammatory bowel disease, poses a serious threat to human health. Currently, safe and effective treatments are not available. This study investigated the protective effect of ginkgolide C (GC), a terpene lactone extracted from Ginkgo biloba leaves, on UC and its underlying mechanism. The results showed that GC remarkably mitigated the severity of DSS-induced colitis in mice, as demonstrated by decreased body weight loss, reduced disease activity index, mitigated tissue damage, and increased colon length. Furthermore, GC inhibited DSS-induced hyperactivation of inflammation-related signaling pathways (NF-κB and MAPK) to reduce the production of inflammatory mediators, thereby mitigating the inflammatory response in mice. GC administration also restored gut barrier function by elevating the number of goblet cells and boosting the levels of tight junction-related proteins (claudin-3, occludin, and ZO-1). In addition, GC rebalanced the intestinal flora of DSS-treated mice by increasing the diversity of the flora, elevating the abundance of beneficial bacteria, such as Lactobacillus and Allobaculum, and decreasing the abundance of harmful bacteria, such as Bacteroides, Oscillospira, Ruminococcus, and Turicibacter. Taken together, these results suggest that GC administration effectively alleviates DSS-induced colitis by inhibiting the inflammatory response, maintaining mucosal barrier integrity, and regulating intestinal flora. This study may provide a scientific basis for the rational use of GC in preventing colitis and other related diseases.

Niclosamide Exposure at Environmentally Relevant Concentrations Efficaciously Inhibited the Growth and Disturbed the Liver-Gut Axis of Adult Male Zebrafish

In the current study, adult male zebrafish fed a normal diet (ND) or high-fat diet (HFD) were exposed to niclosamide (NIC) at environmentally relevant concentrations to reveal the accumulation and distribution in different tissues and evaluate the effects on liver-gut axis. Chemical analysis indicated that the liver bore a greater burden of NIC compared with the brain and gonads in adult zebrafish, and the HFD-fed fish bore greater burden in their liver and brain than those ND-fed fish. The indications from body weight, growth rate, body mass index, micro-CT images, biochemical and pathological changes confirmed that NIC can efficaciously curb weight gain and improve overloads of in plasma insulin and glucose in HFD-fed zebrafish. However, the potential effects on liver-gut axis in ND-fed zebrafish were also elucidated: NIC disturbed mitochondrial energy production, inhibited the glycemic and triacylglycerol biosynthesis but promoted triacylglycerol and free fatty acid catabolism, therefore reduced lipid accumulation in hepatocytes; NIC also impaired the physical barrier, evoked inflammatory and oxidative stress and led to microbiota dysbiosis in the intestine. There findings highlighted the necessity for evaluating its potential impacts on the health of wild animals as well as human beings upon long-term exposure.

Babies, Bugs, and Barriers: Dietary Modulation of Intestinal Barrier Function in Early Life

The intestinal barrier is essential in early life to prevent infection, inflammation, and food allergies. It consists of microbiota, a mucus layer, an epithelial layer, and the immune system. Microbial metabolites, the mucus, antimicrobial peptides, and secretory immunoglobulin A (sIgA) protect the intestinal mucosa against infection. The complex interplay between these functionalities of the intestinal barrier is crucial in early life by supporting homeostasis, development of the intestinal immune system, and long-term gut health. Exclusive breastfeeding is highly recommended during the first 6 months. When breastfeeding is not possible, milk-based infant formulas are the only safe alternative. Breast milk contains many bioactive components that help to establish the intestinal microbiota and influence the development of the intestinal epithelium and the immune system. Importantly, breastfeeding lowers the risk for intestinal and respiratory tract infections. Here we review all aspects of intestinal barrier function and the nutritional components that impact its functionality in early life, such as micronutrients, bioactive milk proteins, milk lipids, and human milk oligosaccharides. These components are present in breast milk and can be added to milk-based infant formulas to support gut health and immunity. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Tight junctions: from molecules to gastrointestinal diseases

Intestinal epithelium functions as a tissue barrier to prevent interaction between the internal compartment and the external milieu. Intestinal barrier function also determines epithelial polarity for the absorption of nutrients and the secretion of waste products. These vital functions require strong integrity of tight junction proteins. In fact, intestinal tight junctions that seal the paracellular space can restrict mucosal-to-serosal transport of hostile luminal contents. Tight junctions can form both an absolute barrier and a paracellular ion channel. Although defective tight junctions potentially lead to compromised intestinal barrier and the development and progression of gastrointestinal (GI) diseases, no FDA-approved therapies that recover the epithelial tight junction barrier are currently available in clinical practice. Here, we discuss the impacts and regulatory mechanisms of tight junction disruption in the gut and related diseases. We also provide an overview of potential therapeutic targets to restore the epithelial tight junction barrier in the GI tract.

The Probiotic Lactobacillus paracasei Ameliorates Diarrhea Cause by Escherichia coli O8via Gut Microbiota Modulation1

Introduction

Koumiss is a fermented horse milk food containing abundant probiotics. Lactobacillus paracasei is a bacterial strain isolated from koumiss that helps regulate the intestinal microbiota. One of the major cause of diarrhea is an imbalance of the intestinal flora. The aim of this study was to investigate whether Lactobacillus paracasei can ameliorate E. coli-induced diarrhea and modulate the gut microbiota.

Methods

Mouse models of diarrhea were established via intragastric E. coli O₈ administration. We then attempted to prevent or treat diarrhea in the mice via intragastric administration of a 3 × 10⁸ CFU/mL L. paracasei cell suspension. The severity of diarrhea was evaluated based on the body weight, diarrhea rate, and index, fecal diameter, ileum injury, hematoxylin-eosin (H&E) staining, and diamine oxidase (DAO) and zonulin expression. Expression of the tight junction (TJ) proteins claudin-1, occludin, and zona occludens (ZO-)1 were detected by immunohistochemistry (IHC). Gastrointestinal mRNA expression levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were detected by real-time polymerase chain reaction (RT-PCR). The microbial composition was analyzed by 16s rRNA sequencing.

Results

The L. paracasei demonstrated excellent therapeutic efficacy against diarrhea. It elevated the TJ protein levels and downregulated proinflammatory cytokines IL-6, IL-1β, TNF-α, and p65, myosin light chain 2 (MLC2), myosin light chain kinase (MLCK). Moreover L. paracasei increased those bacteria, which can product short-chain fatty acid (SCFA) such Alistipes, Odoribacter, Roseburia, and Oscillibacter.

Conclusion

L. paracasei ameliorated diarrhea by inhibiting activation of the nuclear factor kappa B (NF-κB)-MLCK pathway and increasing the abundance of gut microbiota that produce SCFA.

Plasma and fecal zonulin are not altered by a high green leafy vegetable dietary intervention: secondary analysis of a randomized control crossover trial

BACKGROUND

Zonulin is observed in animal models to regulate intestinal permeability and influenced by dietary intake, gut microbiota, and inflammation. We conducted a secondary analysis of a randomized controlled crossover trial (NCT03582306) in individuals with a BMI greater than 30 kg/m² and high habitual red meat intake and low habitual green leafy vegetable (GLV) intake.

METHODS

Participants were provided with frozen GLV during the first or last four weeks (immediate or delayed intervention) of the twelve-week trial. Biological and anthropometric measures were taken at the beginning and at each four-week interval. A subset of 20 participants was selected for this secondary analysis of the intestinal permeability and inflammation-related biomarkers: serum and fecal zonulin; serum lipopolysaccharide binding protein (LBP), Alpha-1-acid glycoprotein 1 (ORM-1), tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and C-reactive protein; 8-hydroxy-2'-deoxyguanosine (8OHdG) and plasma Vitamin K1 as a marker of protocol adherence. Nutrient and food group intake from two-24-h dietary recalls collected at each time point were assessed. Fecal microbiota was measured by 16 s rRNA PCR sequencing. Changes in biological markers, dietary factors, and microbial taxa were assessed with Wilcoxon Sign Ranks Tests. Exploratory analyses of the relationship between changes in outcome variables were conducted with Spearman correlations.

RESULTS

No changes in serum and fecal zonulin and serum LBP were observed. Plasma Vitamin K (p = 0.005) increased, while plasma 8OHdG (p = 0.023) decreased during the intervention compared to the control. The only dietary factors that changed significantly were increases during intervention in Vitamin K and Dark GLV (p < 0.001 for both) compared to control. Fecal microbiota did not change significantly across all times points; however, change in serum zonulin was associated with change in Proteobacteria (ρ = - 0.867, p = 0.001) in females and Bifidobacterium (ρ = - 0.838, p = 0.009) and Bacteroidaceae (ρ = 0.871, p = 0.005) in men.

CONCLUSIONS

A high GLV dietary intervention increased serum zonulin levels and had no effect on fecal zonulin. Lack of concordance between several inflammation-associated biomarkers and zonulin corroborate recent reports of limited utility of zonulin in obese adults free of lower gastrointestinal disease. Trial Registration information: https://clinicaltrials.gov/ct2/show/NCT03582306 (NCT03582306) registered on 07/11/2018.

Effects of Non-Polar Dietary and Endogenous Lipids on Gut Microbiota Alterations: The Role of Lipidomics

Advances in sequencing technologies over the past 15 years have led to a substantially greater appreciation of the importance of the gut microbiome to the health of the host. Recent outcomes indicate that aspects of nutrition, especially lipids (exogenous or endogenous), can influence the gut microbiota composition and consequently, play an important role in the metabolic health of the host. Thus, there is an increasing interest in applying holistic analytical approaches, such as lipidomics, metabolomics, (meta)transcriptomics, (meta)genomics, and (meta)proteomics, to thoroughly study the gut microbiota and any possible interplay with nutritional or endogenous components. This review firstly summarizes the general background regarding the interactions between important non-polar dietary (i.e., sterols, fat-soluble vitamins, and carotenoids) or amphoteric endogenous (i.e., eicosanoids, endocannabinoids-eCBs, and specialized pro-resolving mediators-SPMs) lipids and gut microbiota. In the second stage, through the evaluation of a vast number of dietary clinical interventions, a comprehensive effort is made to highlight the role of the above lipid categories on gut microbiota and vice versa. In addition, the present status of lipidomics in current clinical interventions as well as their strengths and limitations are also presented. Indisputably, dietary lipids and most phytochemicals, such as sterols and carotenoids, can play an important role on the development of medical foods or nutraceuticals, as they exert prebiotic-like effects. On the other hand, endogenous lipids can be considered either prognostic indicators of symbiosis or dysbiosis or even play a role as specialized mediators through dietary interventions, which seem to be regulated by gut microbiota.

Micronutrient Improvement of Epithelial Barrier Function in Various Disease States: A Case for Adjuvant Therapy

The published literature makes a very strong case that a wide range of disease morbidity associates with and may in part be due to epithelial barrier leak. An equally large body of published literature substantiates that a diverse group of micronutrients can reduce barrier leak across a wide array of epithelial tissue types, stemming from both cell culture as well as animal and human tissue models. Conversely, micronutrient deficiencies can exacerbate both barrier leak and morbidity. Focusing on zinc, Vitamin A and Vitamin D, this review shows that at concentrations above RDA levels but well below toxicity limits, these micronutrients can induce cell- and tissue-specific molecular-level changes in tight junctional complexes (and by other mechanisms) that reduce barrier leak. An opportunity now exists in critical care—but also medical prophylactic and therapeutic care in general—to consider implementation of select micronutrients at elevated dosages as adjuvant therapeutics in a variety of disease management. This consideration is particularly pointed amidst the COVID-19 pandemic.

Research Progress in Vitamin A and Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder. Over the past few decades, many studies have investigated the effects of VA supplementation in ASD patients and the relationship between vitamin A (VA) levels and ASD. VA is an essential micronutrient that plays an important role in various systems and biological processes in the form of retinoic acid (RA). Recent studies have shown that serum VA concentration is negatively correlated with the severity of ASD. The lack of VA during pregnancy or early fetal development can affect brain development and lead to long-term or even permanent impairment in the learning process, memory formation, and cognitive function. In addition, VA deficiency has been reported to have a major impact on the gastrointestinal function of children with ASD, while VA supplementation has been shown to improve the symptoms of ASD to a certain extent. This paper provides a comprehensive review of the relationship between VA and ASD.

Priming with Retinoic Acid, an Active Metabolite of Vitamin A, Increases Vitamin A Uptake in the Small Intestine of Neonatal Rats

Given that combined vitamin A (VA) and retinoic acid (RA) supplementation stimulated the intestinal uptake of plasma retinyl esters in neonatal rats, we administrated an RA dose as a pretreatment before VA supplementation to investigate the distinct effect of RA on intestinal VA kinetics. On postnatal days (P) 2 and 3, half of the pups received an oral dose of RA (RA group), while the remaining received canola oil as the control (CN). On P4, after receiving an oral dose of ³H-labeled VA, pups were euthanized at selected times (n = 4–6/treatment/time) and intestine was collected. In both CN and RA groups, intestinal VA mass increased dramatically after VA supplementation; however, RA-pretreated pups had relatively higher VA levels from 10 h and accumulated 30% more VA over the 30-h study. Labeled VA rapidly peaked in the intestine of CN pups and then declined from 13 h, while a continuous increase was observed in the RA group, with a second peak at 10 h and nearly twice the accumulation of ³H-labeled VA compared to CN. Our findings indicate that RA pretreatment may stimulate the influx of supplemental VA into the intestine, and the increased VA accumulation suggests a potential VA storage capacity in neonatal intestine.

Innate Lymphoid Cells and Natural Killer Cells in Bacterial Infections: Function, Dysregulation, and Therapeutic Targets

Infectious diseases represent one of the largest medical challenges worldwide. Bacterial infections, in particular, remain a pertinent health challenge and burden. Moreover, such infections increase over time due to the continuous use of various antibiotics without medical need, thus leading to several side effects and bacterial resistance. Our innate immune system represents our first line of defense against any foreign pathogens. This system comprises the innate lymphoid cells (ILCs), including natural killer (NK) cells that are critical players in establishing homeostasis and immunity against infections. ILCs are a group of functionally heterogenous but potent innate immune effector cells that constitute tissue-resident sentinels against intracellular and extracellular bacterial infections. Being a nascent subset of innate lymphocytes, their role in bacterial infections is not clearly understood. Furthermore, these pathogens have developed methods to evade the host immune system, and hence permit infection spread and tissue damage. In this review, we highlight the role of the different ILC populations in various bacterial infections and the possible ways of immune evasion. Additionally, potential immunotherapies to manipulate ILC responses will be briefly discussed.

Preventive Effect of Lycopene in Dextran Sulfate Sodium-Induced Ulcerative Colitis Mice through the Regulation of TLR4/TRIF/NF-κB Signaling Pathway and Tight Junctions

The preventive effect and molecular mechanism of lycopene (LP) in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice were evaluated. Compared to the DSS group, the LP prevention groups not only significantly inhibited the DSS-induced weight loss, decreased the disease activity index (DAI) score, increased the colon length, and improved inflammation in the colon but also significantly increased the levels of superoxide dismutase (SOD),catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione (GSH) in the colon and reduced inflammatory cytokine, myeloperoxidase (MPO), and malondialdehyde (MDA) levels. Notably, when compared to the DSS group, the protein expression levels of TLR4, TRIF, and p-NF-κB p65 in the mice colon tissue were downregulated and those of tight junction-related proteins were upregulated in the LP + DSS group, with the most significant effect observed in the 10 mg/kg LP + DSS group. These results confirmed that the upregulation of tight junction-related protein expression after blocking the TLR4/TRIF/NF-κB signaling pathway may be one of the mechanisms through which LP prevents UC.

Vitamin A and retinoic acid accelerate the attenuation of intestinal adaptability upon feeding induced by high-fat diet in mice

With its unique cellular plasticity, the small intestinal mucosa exhibits efficient adaptability upon feeding. However, little is known about the effect of high-fat diet (HFD) feeding on this adaption and its underlying mechanism. Herein, we demonstrated that the cell proliferation ability, mitochondrial morphology, and global transcriptomic profile of the small intestine exhibited a prominent discrepancy between the fasted and refed state in mice, which were markedly attenuated by long-term HFD feeding. The retinol (Vitamin A, VA) metabolism pathway was dramatically affected by HFD feeding in the small intestine. Both VA and its active metabolite retinoic acid (RA), with the administration of lipid micelles, promoted the expression of genes involved in lipid absorption and suppressed the expression of genes involved in the cell proliferation of intestinal organoids. Via chip-qPCR and RT-qPCR, genes involved in lipid metabolism and cell proliferation were target genes of RARα/RXRα in small intestinal organoids treated with RA and lipid micelles. The role of VA in the in vivo attenuation of intestinal adaptability, in response to HFD, was evaluated. Mice were fed a normal chow diet, HFD, or HFD diet supplemented with additional 1.5-fold VA for 12 weeks. VA supplementation in HFD accelerated the attenuation of intestinal adaptability upon feeding induced by HFD, promoted lipid absorption gene expression, and increased body weight and serum cholesterol levels. In conclusion, the discrepancy of the small intestine between the fasted and refed state was dramatically attenuated by HFD feeding, in which VA and RA might play important roles.

Present and Future Therapeutic Approaches to Barrier Dysfunction

There is converging and increasing evidence, but also uncertainty, for the role of abnormal intestinal epithelial barrier function in the origin and development of a growing number of human gastrointestinal and extraintestinal inflammatory disorders, and their related complaints. Despite a vast literature addressing factors and mechanisms underlying changes in intestinal permeability in humans, and its connection to the appearance and severity of clinical symptoms, the ultimate link remains to be established in many cases. Accordingly, there are no directives or clinical guidelines related to the therapeutic management of intestinal permeability disorders that allow health professionals involved in the management of these patients to carry out a consensus treatment based on clinical evidence. Instead, there are multiple pseudoscientific approaches and commercial propaganda scattered on the internet that confuse those affected and health professionals and that often lack scientific rigor. Therefore, in this review we aim to shed light on the different therapeutic options, which include, among others, dietary management, nutraceuticals and medical devices, microbiota and drugs, and epigenetic and exosomes-manipulation, through an objective evaluation of the scientific publications in this field. Advances in the knowledge and management of intestinal permeability will sure enable better options of dealing with this group of common disorders to enhance quality of life of those affected.

The Effect of Bacterial Infections, Probiotics and Zonulin on Intestinal Barrier Integrity

The intestinal barrier plays an extremely important role in maintaining the immune homeostasis of the gut and the entire body. It is made up of an intricate system of cells, mucus and intestinal microbiota. A complex system of proteins allows the selective permeability of elements that are safe and necessary for the proper nutrition of the body. Disturbances in the tightness of this barrier result in the penetration of toxins and other harmful antigens into the system. Such events lead to various digestive tract dysfunctions, systemic infections, food intolerances and autoimmune diseases. Pathogenic and probiotic bacteria, and the compounds they secrete, undoubtedly affect the properties of the intestinal barrier. The discovery of zonulin, a protein with tight junction regulatory activity in the epithelia, sheds new light on the understanding of the role of the gut barrier in promoting health, as well as the formation of diseases. Coincidentally, there is an increasing number of reports on treatment methods that target gut microbiota, which suggests that the prevention of gut-barrier defects may be a viable approach for improving the condition of COVID-19 patients. Various bacteria-intestinal barrier interactions are the subject of this review, aiming to show the current state of knowledge on this topic and its potential therapeutic applications.

Effects of iron, vitamin A, and the interaction between the two nutrients on intestinal development and cell differentiation in piglets

This study aimed to investigate the effects of iron, vitamin A (VA) and their interaction on intestinal development and differentiation of cells in suckling piglets. Therefore, 32 Duroc × Landrace × Yorkshire 0-d-old newborn boars with similar body weights were randomly divided into four groups, with eight replicates in each group and one pig in each replicate. All the piglets were breastfed. In addition, the piglets were given normal saline (CON group) or ferrous sulfate (OAFe group) or VA (VA group) or ferrous sulfate and VA (OAFe + VA group) on the 2nd, 7th, 12th, and 17th day, respectively. The piglets were then slaughtered on the 21st day, and intestinal samples were collected. The results showed that: 1) iron (P < 0.001) significantly increased the length, weight, relative weight, and the length to weight ratio of the small intestine. On the other hand, VA had a significant effect on the weight to length ratio (P = 0.015) and relative weight (P < 0.001) of the small intestine; 2) with regard to intestinal morphology, supplementation with iron (P <0.05) had obvious effects on the villus height (VH), crypt depth (CD), villus width (VW), and surface area. Additionally, both VA and interaction of VA and iron increased the VH (P < 0.05) and surface area (P = 0.001). The results also showed that iron (P < 0.01) increased the number of crypt goblet cells, Ki67-positive cells, and endocrine cells. Moreover, both VA and the interaction between VA and iron increased the number of endocrine cells in the villi (P = 0.05); 3) With regard to the mRNA expression levels of stem cell differentiation marker genes, iron (P < 0.05) decreased the expression of trophinin 2 (Trop2), leucine-rich repeat containing G protein-coupled receptor 5 positive (Lgr5+), male-specific lethal 1(Msl1), BMI 1 proto-oncogene, polycomb ring finger (Bmi1), and achaete-scute family bHLH transcription factor 2 (Ascl2). On the other hand, VA increased the expression of Ascl2 (P = 0.001) although the interaction of VA and iron (P < 0.05) had an effect on the expression of secreted phosphoprotein 1 (Spp1) and Bmi1. In addition, VA decreased the gene or mRNA expression of aconitase 1 (Aco1; P < 0.001), transferrin receptor (TFRC; P = 0.001), and solute carrier family 11 member 2 (DMT1; P = 0.003) in the Iron Reactive Element/Iron Regulatory Protein (IRE/IRP) signaling pathway although iron and the interaction of VA and iron had no effect on the genes' expression. The results therefore showed that VA, iron, and their interaction can promote intestinal development and epithelial cell differentiation in piglets.

Negative impacts of microcystin-LR and glyphosate on zebrafish intestine: Linked with gut microbiota and microRNAs?

Microcystin-LR (MC-LR) and glyphosate (GLY) have been classified as a Group 2B and Group 2A carcinogens for humans, respectively, and frequently found in aquatic ecosystems. However, data on the potential hazard of MC-LR and GLY exposure to the fish gut are relatively scarce. In the current study, a subacute toxicity test of zebrafish exposed to MC-LR (35 μg L-1) and GLY (3.5 mg L-1), either alone or in combination was performed for 21 d. The results showed that MC-LR or/and GLY treatment reduced the mRNA levels of tight junction genes (claudin-5, occludin, and zonula occludens-1) and altered the levels of diamine oxidase and D-lactic, indicating increased intestinal permeability in zebrafish. Furthermore, MC-LR and/or GLY treatment remarkably increased the levels of intestinal IL-1β and IL-8 but decreased the levels of IL-10 and TGF-β, indicating that MC-LR and/or GLY exposure induced an inflammatory response in the fish gut. MC-LR and/or GLY exposure also activated superoxide dismutase and catalase, generally upregulated the levels of p53, bax, bcl-2, caspase-3, and caspase-9, downregulated the levels of caspase-8 and caused notable histological injury in the fish gut. Moreover, MC-LR and/or GLY exposure also significantly altered the microbial community in the zebrafish gut and the expression of miRNAs (miR-146a, miR-155, miR-16, miR-21, and miR-223). Chronic exposure to MC-LR and/or GLY can induce intestinal damage in zebrafish, and this study is the first to demonstrate an altered gut microbiome and miRNAs in the zebrafish gut after MC-LR and GLY exposure.

Adaptation Processes of the Remaining Jejunum or Ileum after Extensive Intestinal Resection

PURPOSE

To compare the adaptation processes of the remaining jejunum or ileum after extensive intestinal resection in a growing animal model.

MATERIALS AND METHODS

Forty 21-day old rats were divided into four groups: JG: remaining jejunum group - ileal enterectomy; IG: ileum remaining group - jejunum enterectomy; SHAM: sham-operated group - open-and-close laparotomy; and NO: non-operated animals.

RESULTS

After 3 weeks, JG and IG animals had decreased weights comparing to SHAM and NO animals (p = 0.017 and p = 0.005, respectively). The histomorphometric analysis showed that in JG animals the villi were higher than in SHAM, NO, and IG animals (p = 0.007, p = 0.008, and p = 0.01), the depth of crypts in JG and IG animals was greater than in NO and SHAM animals (p = 0.03, p = 0.002, and p = 0.003 respectively), and muscle layer thickness of the jejunum of JG animals had values greater than SHAM and NO animals (p = 0.01 and p = 0.02, respectively). The Ki-67 expression in the ileum was higher in comparison with the jejunum (p = 0.014). The pro-apoptotic gene (Bax) expression was decreased in JG animals compared to IG, SHAM, and NO animals (p = 0.013, p = 0.024, and p = 0.021). The anti-apoptotic gene (Bcl-XL) expression was decreased in JG animals in comparison to IG and NO animals (p = 0.002 and p = 0.046) although it was increased in the colon of IG animals in comparison to JG, SHAM, and NO animals (p = 0.002, p = 0.001, and p = 0.001, respectively). The Bax/Bcl-XL ratio was higher in JG than in IG animals (p = 0.011).

CONCLUSION

Adaptive responses seemed to be more effective in the ileum than in the jejunum.

Enzyme-Treated Soybean Meal Enhanced Performance via Improving Immune Response, Intestinal Morphology and Barrier Function of Nursery Pigs in Antibiotic Free Diets

Simple Summary

Currently, although extruded full-fat soybean (EFS) and enzyme-treated soybean meal (ESBM) are both commonly used plant proteins in the diets of nursery pigs, there are few studies focusing on comparing the effect of ESBM and EFS on immune response and gut development of pigs. This study found that ESBM replacing EFS could enhance performance by improving immune response, antioxidant status, gut morphology, and barrier function of nursery pigs in antibiotic free diets. The results revealed that ESBM could be an effective plant protein resource to alleviate weaning stress in pigs.

Abstract

This study aims to investigate the effects of ESBM on performance, antioxidant status, immune response, and intestinal barrier function of nursery pigs in antibiotic free diets compared with EFS. A total of 32 Duroc × (Landrace × Yorkshire) barrows (initial body weight of 8.05 ± 0.66 kg, weaned on d 28) were selected and allocated to two treatments with 16 replicates per treatment and one pig per replicate using a complete random design. The treatments included an EFS group (basal diet + 24% EFS; EFS) and an ESBM group (basal diet + 15% ESBM; ESBM). Corn was used to balance energy and diets were iso-nitrogenous at about 18% crude protein. The experiment lasted for 14 days and pigs were slaughtered for sampling on d 14. Compared with EFS, pigs fed ESBM showed enhanced (p < 0.05) gain to feed ratio and average daily gain and a reduced (p < 0.05) diarrhea score. These pigs had increased (p < 0.05) contents of glutathione peroxidase, catalase, superoxide dismutase, IgG, interleukin-10, and ferric reducing ability of plasma, as well as decreased (p < 0.05) malondialdehyde, IL-6, IL-1β, tumor necrosis factor (TNF-α), interferon-γ, thiobarbituric acid-reactive substances, and diamine oxidase level in serum and TNF-α level in the jejunal mucosa. Moreover, these pigs also showed enhanced (p < 0.05) villus height/crypt depth in ileum, villus height in duodenum, protein expression of zonula-occludens-1 in jejunal mucosa, and fecal total volatile fatty acids and butyric acid contents. In conclusion, ESBM replacing EFS could enhance performance via improving immune response, antioxidant status, gut morphology, and barrier function of nursery pigs in antibiotic free diets.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Fecal Microbiome Transplantation from Children with Autism Spectrum Disorder Modulates Tryptophan and Serotonergic Synapse Metabolism and Induces Altered Behaviors in Germ-Free Mice

To determine the relationship of the gut microbiota and its metabolites with autism spectrum disorder (ASD)-like behaviors and preliminarily explore the potential molecular mechanisms, the fecal microbiota from donors with ASD and typically developing (TD) donors were transferred into germ-free (GF) mice to obtain ASD-FMT mice and TD-FMT mice, respectively. Behavioral tests were conducted on these mice after 3 weeks. 16S rRNA gene sequencing of the cecal contents and untargeted metabolomic analysis of the cecum, serum, and prefrontal cortex were performed. Untargeted metabolomics was also used to analyze fecal samples of TD and ASD children. Western blotting detected the protein expression levels of tryptophan hydroxylase 1 (TPH1), serotonin transporter (SERT), and serotonin 1A receptor (5-HT1AR) in the colon and TPH2, SERT, and 5-HT1AR in the prefrontal cortex of mice. ASD-FMT mice showed ASD-like behavior and a microbial community structure different from that of TD-FMT mice. Tryptophan and serotonin metabolisms were altered in both ASD and TD children and ASD-FMT and TD-FMT mice. Some microbiota may be related to tryptophan and serotonin metabolism. Compared with TD-FMT mice, ASD-FMT mice showed low SERT and 5-HT1AR and high TPH1 expression levels in the colon. In the prefrontal cortex, the expression levels of TPH2 and SERT were increased in the ASD-FMT group relative to the TD-FMT group. Therefore, the fecal microbiome of ASD children can lead to ASD-like behaviors, different microbial community structures, and altered tryptophan and serotonin metabolism in GF mice. These changes may be related to changes in some key proteins involved in the synthesis and transport of serotonin.

IMPORTANCE The relationship between the gut microbiota and ASD is not yet fully understood. Numerous studies have focused on the differences in intestinal microbial and metabolism profiles between TD and ASD children. However, it is still not clear if these microbes and metabolites cause the development of ASD symptoms. Here, we collected fecal samples from TD and ASD children, transplanted them into GF mice, and found that the fecal microbiome of ASD children can lead to ASD-like behaviors, different microbial community structures, and altered tryptophan and serotonin metabolism in GF mice. We also demonstrated that tryptophan and serotonin metabolism was also altered in ASD and TD children. Together, these findings confirm that the microbiome from children with ASD may lead to ASD-like behavior of GF mice through metabolites, especially tryptophan and serotonin metabolism.

Treatment of Spleen-Deficiency Syndrome With Atractyloside A From Bran-Processed Atractylodes lancea by Protection of the Intestinal Mucosal Barrier

Atractylodes lancea (Thunb.) DC. (AL) is used in traditional Chinese medicine for the treatment of spleen-deficiency syndrome (SDS). Bran-processed Atractylodes lancea (BAL) has been found to be more effective than unprocessed AL. However, the compound in BAL active against SDS remains unclear. The pharmacological efficacy of BAL and its mechanism of action against SDS were investigated by HPLC-ELSD. Candidate compound AA (atractyloside A) in AL and BAL extracts was identified by HPLC-MS analysis. AA was tested in a rat model of SDS in which body weight, gastric residual rate, and intestinal propulsion were measured, and motilin (MTL), gastrin (GAS), and c-Kit were quantified by enzyme-linked immunosorbent assay. Potential targets and associated pathways were identified based on network pharmacology analysis. mRNA expression levels were measured by qRT-PCR and protein expression levels were measured by Western blot analysis and immunohistochemistry. AA increased body weight, intestinal propulsion, MTL, GAS, and c-Kit levels, while decreasing gastric residual volume and intestinal tissue damage, as same as Epidermal Growth Factor Receptor and Proliferating Cell Nuclear Antigen levels. Seventy-one potential pharmacologic targets were identified. Analysis of protein interaction, Gene Ontology (GO) functional analysis, pathway enrichment analysis, and docking and molecular interactions highlighted MAPK signaling as the potential signal transduction pathway. Validation experiments indicated that treatment with AA increased MTL, GAS, ZO-1, and OCLN levels, while reducing AQP1, AQP3, and FGF2 levels. In addition, phosphorylation of p38 and myosin light-chain kinase (MLCK) expression were inhibited. AA improved gastrointestinal function by protecting the intestinal mucosal barrier via inhibition of the p38 MAPK pathway. The results have clinical implications for the therapy of SDS.

The rationale for a multi-step therapeutic approach based on antivirals, drugs and nutrients with immunomodulatory activity in patients with coronavirus-SARS2-induced disease of different severities

In December 2019, a novel human-infecting coronavirus, named Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), was recognised to cause a pneumonia epidemic outbreak with different degrees of severity in Wuhan, Hubei Province in China. Since then, this epidemic has spread worldwide; in Europe, Italy has been involved. Effective preventive and therapeutic strategies are absolutely required to block this serious public health concern. Unfortunately, few studies about SARS-CoV-2 concerning its immunopathogenesis and treatment are available. On the basis of the assumption that the SARS-CoV-2 is genetically related to SARS-CoV (about 82 % of genome homology) and that its characteristics, like the modality of transmission or the type of the immune response it may stimulate, are still poorly known, a literature search was performed to identify the reports assessing these elements in patients with SARS-CoV-induced infection. Therefore, we have analysed: (1) the structure of SARS-CoV-2 and SARS-CoV; (2) the clinical signs and symptoms and pathogenic mechanisms observed during the development of acute respiratory syndrome and the cytokine release syndrome; (3) the modification of the cell microRNome and of the immune response in patients with SARS infection; and (4) the possible role of some fat-soluble compounds (such as vitamins A, D and E) in modulating directly or indirectly the replication ability of SARS-CoV-2 and host immune response.

Vitamin A deficiency increases the risk of gastrointestinal comorbidity and exacerbates core symptoms in children with autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, and many individuals with ASD have gastrointestinal (GI) comorbidities. Vitamin A (VA) is an essential micronutrient that plays an important role in brain development and GI function.

METHODS

A total of 323 children with ASD and 180 control children were enrolled in this study. Symptoms of ASD were assessed with the Child Autism Rating Scale (CARS), the Social Responsiveness Scale (SRS), and the Autism Behavior Checklist (ABC). Caregivers of the children completed questionnaires about GI symptoms. Serum retinol levels were detected with high-performance liquid chromatography (HPLC).

RESULTS

Children with ASD and with GI comorbidity and constipation had considerably lower serum VA levels than autistic children without these symptoms. VA level was associated with CARS, SRS, and ABC scores, whereas GI symptoms were associated some SRS and ABC scores. The interaction of VAD and GI symptoms appeared to aggravate some of the core symptoms of children with ASD.

CONCLUSIONS

VAD exacerbates core symptoms in children with ASD, and ASD children with GI comorbidities also have more serious core symptoms than ASD children without GI comorbidities. VAD comorbid with GI symptoms aggravates autistic children's core symptoms.

IMPACT

VAD exacerbates core symptoms in children with ASD. ASD children with GI comorbidities have more serious core symptoms than ASD children without GI comorbidities. VAD comorbid with GI symptoms aggravates autistic children's core symptoms. We speculate that VAD might be related to a subtype of ASD that involves GI comorbidities. We believe that our findings will be of fundamental importance to the scientific community.

Vitamin A Deficiency in the Early-Life Periods Alters a Diversity of the Colonic Mucosal Microbiota in Rats

Vitamin A deficiency (VAD) remains a public health issue worldwide, affecting pregnant women and children. The early-life microbiota is a potentially effective intervention target for modulating immune and metabolic development of the host. This paper investigates the effects of VAD during different life periods on the structure of the colonic mucosa microbiota in adolescent rats. The results showed that the concentrations of serum retinol were > ~1.05 μmol/L in maternal VA normal (VAN)rats and < 0.7 μmol/L in maternal VAD rats, while the serum retinol levels were higher than 0.7 μmol/L in the pups of the VAN group and below 0.5 μmol/L in the pups of the VAD group. Compared to the offspring persistent with VAN from embryonic stage (group A), all the remaining groups exhibited an increased ratio of Firmicutes/Bacteroidetes abundance. A metagenome analysis (LEfSe) and a differentially abundant features approach using Metastats for genus abundances revealed that Diaphorobacter and Psychrobacter were increased in the offspring persistent with VAD from embryonic stage (group B);Bifidobacterium was decreased and Staphylococcus was increased in the offspring with VAD after weaning (group C); Propionibacterium and Enterobacter were increased significantly in the offspring with VAD during gestation(group E); and Ochrobactrum was increased in group B and the offspring with VAD during gestation and lactation(group D). Faecalibacterium abundance was significantly and positively related to serum retinol levels, while that of Staphylococcus was significantly and negatively correlated with serum retinol levels. VAD in different life periods can alter the gut microbiome in rats, but VAD in the early-life periods (especially gestation and/or lactation) leads to a diversity of the colonic mucosal microbiota in adolescent rats as well as an imbalance of the ratio between Firmicutes and Bacteroidetes. The early-life period may become a time window of VA intervention to improve intestinal microbiota caused by VA deficiency, but the specific mechanism requires more in-depth research.

Vitamin A regulates fibroblast growth factor 23 (FGF23)

OBJECTIVES

Renal phosphate and vitamin D metabolism are regulated by proteohormone fibroblast growth factor 23 (FGF23), which is secreted by bone cells. FGF23 inhibits phosphate reabsorption and the production of calcitriol, active vitamin D (1,25(OH)₂D₃). FGF23 generated by other cells exerts further paracrine effects in the liver, heart, and immune system. The FGF23 plasma concentration is positively associated with the onset and progression of kidney and cardiovascular diseases, disclosing FGF23 as a potential disease biomarker. The effects of vitamin A on the expression of FGF23 are controversial. Vitamin A components, retinoids, are mainly effective through nuclear retinoic acid receptors (RAR) and exert different effects on bone. The aim of this study was to clarify whether vitamin A modulates the production of FGF23.

METHODS

We studied the relevance of vitamin A for FGF23 production. Fgf23 transcripts were determined by real-time quantitative polymerase chain reaction in UMR106 osteoblast-like cells and IDG-SW3 osteocytes. FGF23 protein in the cell culture supernatant was measured by enzyme-linked immunosorbent assay.

RESULTS

All-trans-retinoic acid, retinyl acetate, RAR agonist TTNPB (4-[(E)-2-(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid), and 13-cis-retinoic acid downregulated the expression of the Fgf23 gene in a dose-dependent manner. This effect was significantly attenuated by RAR antagonist AGN193109 (4-[2-[5,6-Dihydro-5,5-dimethyl-8-(4-methylphenyl)-2-naphthalenyl]ethynyl]benzoic acid).

CONCLUSION

The present study demonstrated that vitamin A is a potent suppressor of FGF23 production through RAR.

Effects of 10.6-μm laser moxibustion and electroacupuncture at ST36 in a 5-Fu-induced diarrhea rat model

OBJECTIVE

The aim of this study was to investigate the effect of 10.6-μm laser moxibustion and electroacupuncture in 5-fluorouracil (5-Fu)-induced diarrhea model rats.

METHODS

Forty-eight Sprague Dawley rats were randomly divided into 4 groups: a normal group, model group, 10.6-μm laser moxibustion (LM) group, and electroacupuncture (EA) group. Diarrhea was induced by 5-Fu (50 mg/kg) injection in 36 rats; the LM and EA groups received treatment at acupoint ST36 (Zusanli) on hind limbs once a day for 6 days.

RESULTS

5-Fu injection caused body weight decline and diarrhea. From the 5th to 7th day, the LM group showed higher body weights than the model group (P < 0.05). On the 6th day, diarrhea score of the LM group was better than that of the EA group (P < 0.05). Both scores of the LM group and EA group were better than that of model group (P < 0.05). The LM group and EA group both had better intestine pathological scores and lower endotoxin (ET) and diamine oxide (DAO) activity than the model group (P < 0.01). The LM group got better pathological scores than the EA group (P < 0.01). Ultramicroscopic structures of the model group showed severe damage while the LM group and EA group remained good in their small intestines. The model group had obviously decreased occludin protein in intestine tissues than the control group (P < 0.01), while occludin expressions in the LM group and EA group were both obviously increased compared with the model group (P < 0.01).

CONCLUSION

LM and EA treatment on ST36 could alleviate damage to intestinal barrier function and alleviate diarrhea caused by 5-Fu.

Innate Lymphoid Cells: Important Regulators of Host-Bacteria Interaction for Border Defense

Innate lymphoid cells (ILCs) are a recently discovered type of innate immune lymphocyte. They include three different groups classified by the nature of the transcription factors required for their development and by the cytokines they produce. ILCs mainly reside in tissues close to the mucosal barrier such as the respiratory and gastrointestinal tracts. Due to their close proximity to the mucosal surface, ILCs are exposed to a variety of both commensal and pathogenic bacteria. Under non-pathological conditions, ILCs have been shown to be important regulators for the maintenance of tissue homeostasis by mutual interactions with the microbiome. Besides these important functions at homeostasis, several studies have also provided emerging evidence that ILCs contribute to defense against pathogenic bacterial infection by responding rapidly to the pathogens as well as orchestrating other immune cells. In this review, we summarize recent advances in our understanding of the interactions of ILCs and bacteria, with special focus on the function of the different ILC subsets in bacterial infections.

Tannic acid prevents post-weaning diarrhea by improving intestinal barrier integrity and function in weaned piglets

Background

Tannic acid (TA) is potential to reduce diarrhea in weaning pigs, but knowledge about the influence of TA on intestinal barrier integrity and function is still scarce. This experiment was conducted to investigate the effects of dietary TA supplementation on growth performance, diarrhea rate, intestinal barrier integrity and function of weaned pigs.

Methods

A total of 108 crossbred (Duroc × Landrace × Yorkshire) piglets, with an initial average body weight of 6.60 ± 0.27 kg, were allotted to 3 groups (6 pigs/pen and 6 replicates/group) in a randomized complete block design according to their gender and body weight. Piglets were fed the basal diet with 0 (control, CON), 0.2% and 1.0% TA, respectively. The trial lasted for 28 d.

Results

Compared with the CON group, dietary 0.2% and 1.0% TA supplementation didn’t affect ADFI, ADG and F:G (P > 0.05), but reduced diarrhea rate, diarrhea index and diarrhea score of piglets (P < 0.05), reduced diamine oxidase (DAO) activity and D-lactic acid concentration in serum (P < 0.01). The higher occludin expression and localization were observed in the duodenum, jejunum and ileum after supplementation with 0.2% or 1.0% TA (P < 0.05). Adding 0.2% TA to diet significantly decreased crypt depth, increased villus height/crypt depth ratio in the duodenum (P < 0.05), and dietary 1.0% TA tended to decrease crypt depth (P < 0.10) and significantly decreased villus height (P < 0.05) of the ileum. Moreover, lower malondialdehyde content in the ileum was detected in the pigs fed 1.0% TA (P < 0.05). In the duodenum, both 0.2% and 1.0% TA groups had higher occludin (OCLN) mRNA and 0.2% TA group had higher zonula occludens-2 (ZO-2) level (P < 0.05). Meanwhile, dietary 1.0% TA supplementation tended to up-regulate OCLN mRNA levels in the jejunum (P < 0.10) and 0.2% TA supplementation tended to up-regulate zonula occludens-1 (ZO-1) mRNA levels in the ileum (P < 0.10).

Conclusion

In conclusion, dietary supplementation of 0.2% or 1.0% TA could effectively alleviate post-weaning diarrhea without altering growth performance in weaned piglets, which might be achieved by improving intestinal barrier integrity and function.

Regulation of the intestinal barrier by nutrients: The role of tight junctions

Tight junctions (TJs) play an important role in intestinal barrier function. TJs in intestinal epithelial cells are composed of different junctional molecules, such as claudin and occludin, and regulate the paracellular permeability of water, ions, and macromolecules in adjacent cells. One of the most important roles of the TJ structure is to provide a physical barrier to luminal inflammatory molecules. Impaired integrity and structure of the TJ barrier result in a forcible activation of immune cells and chronic inflammation in different tissues. According to recent studies, the intestinal TJ barrier could be regulated, as a potential target, by dietary factors to prevent and reduce different inflammatory disorders, although the precise mechanisms underlying the dietary regulation remain unclear. This review summarizes currently available information on the regulation of the intestinal TJ barrier by food components.

The Effects of Probiotic/Synbiotic on Serum Level of Zonulin as a Biomarker of Intestinal Permeability: A Systematic Review and Meta-Analysis

Background:

This systematic review and meta-analysis was conducted to obtain a conclusive result on the influence of probiotics/synbiotic on serum levels of zonulin. Data related to serum levels of zonulin were extracted to determine the effects of probiotic/synbiotic on intestinal permeability.

Methods:

The literature search was conducted across the Cochrane Central Register of Controlled Trials, Pub-Med, Scopus and ISI Web of Science, Search up to Nov 2018. Clinical trials evaluating the effect of probiotic/synbiotic on serum zonulin levels of all human subjects were included.

Results:

Nine studies (including 496 intervention and 443 control subjects) met the inclusion criteria for the meta-analysis. According to the meta-analysis, probiotic/synbiotic has a significant effect on serum zonulin reduction (WMD=−10.55 [95% CI: −17.76, −3.34]; P=0.004). However, the high level of heterogeneity was observed among the studies (I²=97.8, P<0.001). The subgroup analysis suggested study quality, blinding, study duration, Participants age, subject’s health status and supplement type as sources of heterogeneity.

Conclusion:

Probiotic/synbiotic have favorable effects on serum levels of zonulin as a measure of intestinal permeability. However, the results should be interpreted with caution due to the high heterogeneity and further evidence is required before definitive recommendations can be made.

Association of vitamin A deficiency with early childhood stunting in Uganda: A population-based cross-sectional study

BACKGROUND

Despite the high prevalence of childhood protein-energy malnutrition and vitamin A deficiency in sub-Saharan Africa, their association has not been explored in this region. A better understanding of the epidemiologic link could help define effective preventive strategies. We aimed to explore the association of vitamin A deficiency (VAD) with stunting, wasting, and underweight among preschool children in Uganda.

METHOD

We analyzed a population-based, cross-sectional data of 4,765 children aged 6-59 months who participated in 2016 Demographic and Health Surveys conducted in Uganda. We utilized generalized linear mixed-effects models with logit link function, adjusting for potential confounders to estimate associations between VAD and stunting, wasting, and underweight.

RESULTS

The prevalence of VAD was 8.9% (95% CI: 8.1% to 9.6%, n = 424). Twenty-seven percent were stunted (95% CI: 26.1% to 28.6, n = 1302), 4% wasted (95% CI: 3.6% to 4.7%, n = 196), and 17% underweight (95% CI: 16.0% to 18.2%, n = 813). After adjusting for household factors (e.g., wealth index, education and working status of parents, owning land for agriculture, livestock, herds, or farm animals), vitamin A supplementation, and community factors (e.g., population density, crop growing season lengths, place of residence), children with VAD had 43% higher odds of stunted growth than those without VAD (adjusted odds ratio, 1.43 (95% CI: 1.08 to 1.89, p = 0.01). No association was observed between VAD and wasting or underweight.

CONCLUSION

Vitamin A deficiency was associated with higher odds of stunting, and the association was independent of the individual, household, and community-level variables.

Effects of dietary fiber sources during late gestation and lactation on sow performance, milk quality, and intestinal health in piglets1

This study was conducted to investigate the effects of dietary supplementation with 2 sources of fiber, sugar beet pulp (SBP), and wheat bran (WB), on sow performance, milk quality, and intestinal health in piglets. Forty-five multiparous sows at day 85 of gestation were allocated to the following 3 treatments: 1) a corn-soybean meal basal diet (CON); 2) the CON diet supplemented with 20% SBP in gestation and 10% SBP in lactation (SBP); and 3) the CON diet supplemented with 30% WB in gestation and 15% WB in lactation (WB). The SBP diets increased (P < 0.05) sow ADFI during lactation, litter and piglet weaning weight, piglet ADG, immunoglobulin A (IgA), and interleukin-10 (IL-10) levels in the colostrum and IgA levels in the milk, while the WB diets only increased (P < 0.05) IL-10 levels in the milk when compared with the CON diets. Piglets from SBP-fed sows had greater (P < 0.05) serum growth hormone and insulin-like growth factor-1 levels than those from WB-fed or CON-fed sows, whereas piglets from WB-fed sows had greater (P < 0.05) serum GH levels than those from CON-fed sows. Serum diamine oxidase activity, endotoxin, IL-6, and tumor necrosis factor-α (TNF-α) levels were reduced (P < 0.05) in piglets from SBP-fed or WB-fed sows. Piglets from SBP-fed sows also had greater (P < 0.05) serum IL-10 levels than those from CON-fed sows. The ileal mRNA expression of TNF-α was reduced (P < 0.05) in piglets from SBP-fed or WB-fed sows. Piglets from SBP-fed sows had lower (P < 0.05) IL-6 expression, and greater (P < 0.05) IL-10 expression and secretory immunoglobulin A (SIgA) levels in the ileum than those from WB- or CON-fed sows. Piglets from WB-fed sows had greater (P < 0.05) IL-10 expression and SIgA levels compared with those from CON-fed sows. The ileal mRNA expression of occludin in the ileum was greater (P < 0.05) in piglets from SBP-fed sows than those from CON-fed sows. The ileal mRNA expression of ZO-1 was greater (P < 0.05) in piglets from WB-fed sows than those from CON-fed sows, but lower (P < 0.05) than those from SBP-fed sows. Piglets from SBP-fed sows had greater (P < 0.05) abundance of Christensenellaceae and butyrate levels in the colon, while piglets from WB-fed sows had greater (P < 0.05) abundance of Lactobacillaceae. Collectively, maternal SBP supplementation was more effective than WB in improving milk quality, enhancing growth performance and intestinal barrier function, and ameliorating intestinal inflammation in piglets.