Restoration of impaired intestinal barrier function by the hydrolysed casein diet contributes to the prevention of type 1 diabetes in the diabetes-prone BioBreeding rat

Modulating the Gut Microbiota and Metabolites with Traditional Chinese Medicines: An Emerging Therapy for Type 2 Diabetes Mellitus and Its Complications

Currently, an estimated 537 million individuals are affected by type 2 diabetes mellitus (T2DM), the occurrence of which is invariably associated with complications. Glucose-lowering therapy remains the main treatment for alleviating T2DM. However, conventional antidiabetic agents are fraught with numerous adverse effects, notably elevations in blood pressure and lipid levels. Recently, the use of traditional Chinese medicines (TCMs) and their constituents has emerged as a preferred management strategy aimed at curtailing the progression of diabetes and its associated complications with fewer adverse effects. Increasing evidence indicates that gut microbiome disturbances are involved in the development of T2DM and its complications. This regulation depends on various metabolites produced by gut microbes and their interactions with host organs. TCMs' interventions have demonstrated the ability to modulate the intestinal bacterial microbiota, thereby restoring host homeostasis and ameliorating metabolic disorders. This review delves into the alterations in the gut microbiota and metabolites in T2DM patients and how TCMs treatment regulates the gut microbiota, facilitating the management of T2DM and its complications. Additionally, we also discuss prospective avenues for research on natural products to advance diabetes therapy.

Milk: A Natural Guardian for the Gut Barrier

The gut barrier plays an important role in health maintenance by preventing the invasion of dietary pathogens and toxins. Disruption of the gut barrier can cause severe intestinal inflammation. As a natural source, milk is enriched with many active constituents that contribute to numerous beneficial functions, including immune regulation. These components collectively serve as a shield for the gut barrier, protecting against various threats such as biological, chemical, mechanical, and immunological threats. This comprehensive review delves into the active ingredients in milk, encompassing casein, α-lactalbumin, β-lactoglobulin, lactoferrin, the milk fat globular membrane, lactose, transforming growth factor, and glycopeptides. The primary focus is to elucidate their impact on the integrity and function of the gut barrier. Furthermore, the implications of different processing methods of dairy products on the gut barrier protection are discussed. In conclusion, this study aimed to underscore the vital role of milk and dairy products in sustaining gut barrier health, potentially contributing to broader perspectives in nutritional sciences and public health.

Identification of claudin-2 as a promising biomarker for early diagnosis of pre-diabetes

Introduction: Pre-diabetes, a high-risk metabolic state, is situated between normal glucose homeostasis and diabetes. Early identification of pre-diabetes offers opportunities for intervention and diabetes reversal, highlighting the crucial need to investigate reliable biomarkers for this condition. Methods: We conducted an in-depth bioinformatics analysis of clinical samples from non-diabetic (ND), impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) categories within the GSE164416 dataset. Thereafter the HFD and STZ treated mice were used for validation. Results: This analysis identified several codifferentially expressed genes (Co-DEGs) for IGT and T2DM, including CFB, TSHR, VNN2, APOC1, CLDN2, SLPI, LCN2, CXCL17, FAIM2, and REG3A. Validation of these genes and the determination of ROC curves were performed using the GSE76895 dataset. Thereafter, CLDN2 was selected for further verification. Gene expression analysis and immunofluorescence analysis revealed a significant upregulation of CLDN2 expression in the pancreas islets of mice in the high-fat diet and T2DM groups compared to the control group. Similarly, serum level of CLDN2 in patients with IGT and T2DM were significantly higher than those in the healthy group. Discussion: These results suggest that CLDN2 can serve as a novel biomarker for pre-diabetes, providing a new direction for future research in the prevention of type 2 diabetes.

Efficacy of faecal microbiota transplantation in patients with progressive supranuclear palsy-Richardson's syndrome: a phase 2, single centre, randomised clinical trial

Background

Faecal microbiota transplantation (FMT) has demonstrated efficacy in treating gastrointestinal (GI) diseases, such as Clostridium difficile infection (CDI) and inflammatory bowel disease (IBD). GI dysfunction is a frequent and occasionally dominating symptom of progressive supranuclear palsy-Richardson's syndrome (PSP-RS). However, it is not known whether FMT has clinical efficacy for PSP-RS.

Methods

This 36-week, randomised, placebo-controlled, parallel-group, phase 2 clinical trial was performed at a university tertiary referral hospital in China. From August 15 2021 to December 31 2021, a total of 68 newly diagnosed patients with PSP-RS (male 40 [59%], female 28 [41%]) who had never received any antiparkinsonian medications were enrolled and randomly assigned to receive either healthy donor FMT (n = 34, FMT group) or a mixture of 0.9% saline and food colouring (E150c) as sham transplantation (n = 34, placebo group) through transendoscopic enteral tubing (TET). Two days after oral antibiotics, participants received 1 week of transplantation. After an interval of 4 weeks, retransplantation was performed. Then, the last transplantation was given after another interval of 4 weeks, and the participants were followed up for 24 weeks (week 36). Clinicaltrials.gov identifier: ChiCTR-2100045397.

Findings

Among 68 patients who were randomised (mean age, 67.2 (SD 5.1); 40 [59%] were male, 28 [41%] were female), 63 participants completed the trial. Efficacy analyses were performed on the intention-to-treat (ITT) analysis set. At week 16, the mean PSP Rating Scale (PSPRS) scores (the primary outcome) improved from 40.1 (SD 7.6) to 36.9 (SD 5.9) in the FMT group, whereas the scores changed from 40.1 (SD 6.9) to 41.7 (SD 6.2) in the placebo group, for a treatment benefit of 4.3 (95% CI, 3.2-5.4) (P < 0.0001). After 3-cycle intervention, symptoms of constipation, depression, and anxiety (the secondary outcome) improved significantly at week 16 in the FMT group compared with the placebo group, the majority of which were maintained at the 24-week follow-up (week 36).

Interpretation

Our findings suggest that, compared with placebo, FMT treatment significantly improved motor and nonmotor symptoms in patients with PSP-RS, as well as reduced intestinal inflammation and enhanced the intestinal barrier by regulating the intestinal microbiota composition.

Funding

The National Natural Science Foundation of China (No. 82122022, 82171248, 81873791, and 82230084), Natural Science Foundation of Henan Province for Excellent Young Scholars (no. 202300410357), and Henan Province Young and Middle-Aged Health Science and Technology Innovation Talent Project (YXKC2020033).

Current Practice in Pediatric Cow's Milk Protein Allergy-Immunological Features and Beyond

Cow's milk protein allergy is one of the most common pediatric food allergies. It poses a significant socioeconomic burden in industrialized countries and has a profound effect on the quality of life of affected individuals and their families. Diverse immunologic pathways can lead to the clinical symptoms of cow's milk protein allergy; some of the pathomechanisms are known in detail, but others need further elucidation. A comprehensive understanding of the development of food allergies and the features of oral tolerance could have the potential to unlock more precise diagnostic tools and novel therapeutic approaches for patients with cow's milk protein allergy.

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.

Shaping infant development from the inside out: Bioactive factors in human milk

Human breast milk is the optimal nutrition for all infants and is comprised of many bioactive and immunomodulatory components. The components in human milk, such as probiotics, human milk oligosaccharides (HMOs), extracellular vesicles, peptides, immunoglobulins, growth factors, cytokines, and vitamins, play a critical role in guiding neonatal development beyond somatic growth. In this review, we will describe the bioactive factors in human milk and discuss how these factors shape neonatal immunity, the intestinal microbiome, intestinal development, and more from the inside out.

Children with Delayed-Type Cow's Milk Protein Allergy May Be at a Significant Risk of Developing Immediate Allergic Reactions Upon Re-introduction

Background

Cow's Milk Protein Allergy (CMPA) is the most common food allergy in children. The reaction is classified into IgE-mediated immediate reaction and delayed-onset, according to the underlying immune mechanism, and hence, the timing of the symptoms. Case reports suggest that children, with delayed CMPA reactions on elimination diet, may develop severe immediate reactions on reintroduction.

Aim

The objective of this study was to evaluate the incidence and the risk factors of developing immediate reactions to milk and dairy products in children with CMPA whose initial presentations were of delayed type.

Methods

A retrospective chart review of children, aged 0-12 years, presented with delayed type CMPA reactions to the allergy-clinical immunology clinics, was performed. The diagnosis was made clinically, and with appropriate allergy tests when indicated.

Results

Sixty children were included. Males:female ratio was 1.7:1. Family history of atopy was in 72%, and 57% had personal history of atopy. Sixty percent were not breast fed. The most common concomitant food allergy was egg. The most common initial presentation was diarrhea without protein loss or bleeding followed by exacerbation of atopic dermatitis upon exposure to dairy products. Immediate reactions developed in 21.6% upon re-exposure. There were significant associations with concomitant food allergy (OR 56.6 (3.15-1016.1) P<0.0001), especially eggs (OR 12.85 (3.09-53.5) P<0.01).

Conclusion

Children with CMPA, who present with delayed-type allergic reactions, may be at a significant risk of developing immediate reactions upon reintroduction. Evaluation of possible IgE-mediated allergic reactions before reintroduction may be advisable.

Zi Shen Wan Fang Attenuates Neuroinflammation and Cognitive Function Via Remodeling the Gut Microbiota in Diabetes-Induced Cognitive Impairment Mice

Background : Cognitive dysfunction is a critical complication of diabetes mellitus, and there are still no clinically approved drugs. Zi Shen Wan Fang (ZSWF) is an optimized prescription composed of Anemarrhenae Rhizoma, Phellodendri Chinensis Cortex, and Cistanches Herba. The purpose of this study is to investigate the effect of ZSWF on DCI and explore its mechanism from the perspective of maintaining intestinal microbial homeostasis in order to find an effective prescription for treating DCI. Methods: The diabetes model was established by a high-fat diet combined with intraperitoneal injections of streptozotocin (STZ, 120 mg/kg) and the DCI model was screened by Morris water maze (MWM) after 8 weeks of continuous hyperglycemic stimulation. The DCI mice were randomly divided into the model group (DCI), the low- and high-ZSWF-dose groups (9.63 g/kg, 18.72 g/kg), the mixed antibiotic group (ABs), and the ZSWF combined with mixed antibiotic group (ZSWF + ABs). ZSWF was administered orally once a day for 8 weeks. Then, cognitive function was assessed using MWM, neuroinflammation and systemic inflammation were analyzed by enzyme-linked immunosorbent assay kits, intestinal barrier integrity was assessed by hematoxylin-eosin (HE) staining and Western blot and high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Furthermore, the alteration to intestinal flora was monitored by 16S rDNA sequencing. Results: ZSWF restored cognitive function in DCI mice and reduced levels of proinflammatory cytokines such as IL-1β, IL-6, and TNF-α. Moreover, ZSWF protected the integrity of the intestinal barrier by increasing intestinal ZO-1 and occludin protein expression and decreasing urinary lactulose to mannitol ratio. In addition, ZSWF reshaped the imbalanced gut microbiota in DCI mice by reversing the abundance changes of a wide range of intestinal bacteria at the phyla and genus levels. In contrast, removing gut microbiota with antibiotics partially eliminated the effects of ZSWF on improving cognitive function and reducing inflammation, confirming the essential role of gut microbiota in the improvement of DCI by ZSWF. Conclusion: ZSWF can reverse cognitive impairment in DCI mice by remolding the structure of destructed gut microbiota community, which is a potential Chinese medicine prescription for DCI treatment.

Altered epithelial barrier functions in the colon of patients with spina bifida

Our objectives were to better characterize the colorectal function of patients with Spina Bifida (SB). Patients with SB and healthy volunteers (HVs) completed prospectively a standardized questionnaire, clinical evaluation, rectal barostat, colonoscopy with biopsies and faecal collection. The data from 36 adults with SB (age: 38.8 [34.1-47.2]) were compared with those of 16 HVs (age: 39.0 [31.0-46.5]). Compared to HVs, rectal compliance was lower in patients with SB (p = 0.01), whereas rectal tone was higher (p = 0.0015). Ex vivo paracellular permeability was increased in patients with SB (p = 0.0008) and inversely correlated with rectal compliance (r = - 0.563, p = 0.002). The expression of key tight junction proteins and inflammatory markers was comparable between SB and HVs, except for an increase in Claudin-1 immunoreactivity (p = 0.04) in SB compared to HVs. TGFβ1 and GDNF mRNAs were expressed at higher levels in patients with SB (p = 0.02 and p = 0.008). The levels of acetate, propionate and butyrate in faecal samples were reduced (p = 0.04, p = 0.01, and p = 0.02, respectively). Our findings provide evidence that anorectal and epithelial functions are altered in patients with SB. The alterations in these key functions might represent new therapeutic targets, in particular using microbiota-derived approaches.Clinical Trials: NCT02440984 and NCT03054415.

Endotoxin Translocation and Gut Barrier Dysfunction Are Related to Variceal Bleeding in Patients With Liver Cirrhosis

Background

Bacterial infections are associated with the risk of variceal bleeding through complex pathophysiologic pathways.

Objectives

The primary objective of the present case-control study was to investigate the role of bacterial translocation and intestinal barrier dysfunction in the pathogenesis of variceal bleeding. A secondary objective was to determine independent predictors of key outcomes in variceal bleeding, including bleeding-related mortality.

Methods

Eighty-four (n = 84) consecutive patients participated in the study, 41 patients with acute variceal bleeding and 43 patients with stable cirrhosis, and were followed up for 6 weeks. Peripheral blood samples were collected at patient admission and before any therapeutic intervention.

Results

Child-Pugh (CP) score (OR: 1.868; p = 0.044), IgM anti-endotoxin antibody levels (OR: 0.954; p = 0.016) and TGF-β levels (OR: 0.377; p = 0.026) were found to be significant predictors of variceal bleeding. Regression analysis revealed that albumin (OR: 0.0311; p = 0.023), CRP (OR: 3.234; p = 0.034) and FABP2 levels (OR:1.000, p = 0.040), CP score (OR: 2.504; p = 0.016), CP creatinine score (OR: 2.366; p = 0.008), end-stage liver disease model (MELD), Na (OR: 1.283; p = 0.033), portal vein thrombosis (OR: 0.075; p = 0.008), hepatocellular carcinoma (OR: 0.060; p = 0.003) and encephalopathy (OR: 0.179; p = 0.045) were significantly associated with 6-week mortality.

Conclusions

Bacterial translocation and gut barrier impairment are directly related to the risk of variceal bleeding. Microbiota-modulating interventions and anti-endotoxin agents may be promising strategies to prevent variceal bleeding.

Implication of Intestinal Barrier Dysfunction in Gut Dysbiosis and Diseases

The intestinal mucosal barrier, also referred to as intestinal barrier, is widely recognized as a critical player in gut homeostasis maintenance as it ensures the complex crosstalk between gut microbes (both commensals and pathogens) and the host immune system. Highly specialized epithelial cells constantly cope with several protective and harmful agents to maintain the multiple physiological functions of the barrier as well as its integrity. However, both genetic defects and environmental factors can break such equilibrium, thus promoting gut dysbiosis, dysregulated immune-inflammatory responses, and even the development of chronic pathological conditions. Here, we review and discuss the molecular and cellular pathways underlying intestinal barrier structural and functional homeostasis, focusing on potential alterations that may undermine this fine balance.

Effect of Early Feeding on Intestinal Permeability and Inflammation Markers in Infants with Genetic Susceptibility to Type 1 Diabetes: A Randomized Clinical Trial

OBJECTIVES

To assess whether weaning to an extensively hydrolyzed formula (EHF) decreases gut permeability and/or markers of intestinal inflammation in infants with HLA-conferred diabetes susceptibility, when compared with conventional formula.

STUDY DESIGN

By analyzing 1468 expecting biological parent pairs for HLA-conferred susceptibility for type 1 diabetes, 465 couples (32 %) potentially eligible for the study were identified. After further parental consent, 332 babies to be born were randomized at 35th gestational week. HLA genotyping was performed at birth in 309 infants. Out of 87 eligible children, 73 infants participated in the intervention study: 33 in the EHF group and 40 in the control group. Clinical visits took place at 3, 6, 9, and 12 months of age. The infants were provided either EHF or conventional formula whenever breastfeeding was not available or additional feeding was required over the first 9 months of life. The main outcome was the lactulose to mannitol ratio (L/M ratio) at 9 months. The secondary outcomes were L/M ratio at 3, 6, and 12 months of age, and fecal calprotectin and human beta-defensin 2 (HBD-2) levels at each visit.

RESULTS

Compared with controls, the median L/M ratio was lower in the EHF group at 9 months (.006 vs .028; P = .005). Otherwise, the levels of intestinal permeability, fecal calprotectin, and HBD-2 were comparable between the two groups, although slight differences in the age-related dynamics of these markers were observed.

CONCLUSIONS

It is possible to decrease intestinal permeability in infancy through weaning to an extensively hydrolyzed formula. This may reduce the early exposure to dietary antigens.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01735123.

Intestinal permeability in type 1 diabetes: An updated comprehensive overview

The etiopathogenesis of the autoimmune disease type 1 diabetes (T1D) is still largely unknown, however, both genetic and environmental factors contribute to the development of the disease. A major contact surface for environmental factors is the gastrointestinal (GI) tract, where barrier defects in T1D likely cause diabetogenic antigens to enter the body tissues, contributing to beta-cell autoimmunity. Human and animal research imply that increased intestinal permeability is an important disease determinant, although the underlying methodologies, interpretations and conclusions are diverse. In this review, an updated comprehensive overview on intestinal permeability in patients with T1D and animal models of T1D is provided in the categories: in vivo permeability, ex vivo permeability, zonulin, molecular permeability and blood markers. Across categories, there is consistency pointing towards increased intestinal permeability in T1D. In animal models of T1D, the intestinal permeability varies with age and strains implying a need for careful selection of method and experimental setup. Furthermore, dietary interventions that affect diabetes incidence in animal models does also impact the intestinal permeability, suggesting an association between increased intestinal permeability and T1D development.

Analysis of jejunum microbiota of HFD/STZ diabetic rats

Currently, several studies propose that the dominant intestinal bacteria are core flora. Besides keeping the homeostasis of the intestinal environment, the intestinal microflora also plays a role in body metabolism, production of some vitamins, and control of barrier function. The study aimed to investigate the jejunum microbiota in diabetic rats as well as it's the relationship with Ceftriaxone sodium-mediated gut dysbiosis, diabetic parameters, and intestinal permeability. Thirty-two Wistar rats (Male) were enrolled and divided into four groups (A, B, C, and D; N = 8). Subsequently, T2DM was induced in C and D groups by HFD/STZ model and then gut dysbiosis in B and D groups via intragastric administration of Ceftriaxone sodium for two weeks. The food-water intake, body weight, fasting blood glucose, plasma insulin, HOMA-IR, intestinal permeability, and jejunum microbiota and it's histology were investigated. In this study, T2DM was associated with a significant decrease in the richness and diversity of jejunum microbiota, elevation in the intestinal permeability, and higher abundance of some opportunistic pathogens. Ceftriaxone sodium-induced gut dysbiosis declined food-water intake, damagedthe villi of jejunum tissue, increased intestinal permeability, and affected the diversity of jejunum microbiota. In diabetic rats, Ceftriaxone sodium-mediated gut dysbiosis also declined the abundance of someSCFAs bacteria and raised the abundant of some opportunistic bacteria such as Staphylococcus_sciuri. Interestingly, we found that several bacteria were negatively correlated with HOMA-IR, fasting blood glucose, body weight, and intestinal permeability. Overall, the study highlighted the jejunum microflora alterations in HFD/STZ diabetic rats and assessed the effect of Ceftriaxone sodium-induced gut dysbiosis on diabetic parameters, jejunum microbiota and histology, and intestinal permeability, which are of potential for further studies.

Depletion of the gut microbiota differentially affects the impact of whey protein on high-fat diet-induced obesity and intestinal permeability

Whey protein isolate (WPI) is considered a dietary solution to obesity. However, the exact mechanism of WPI action is still poorly understood but is probably connected to its beneficial effect on energy balance, adiposity, and metabolism. More recently its ability to modulate the gut microbiota has received increasing attention. Here, we used a microbiota depletion, by antibiotic cocktail (ABX) administration, to investigate if the gut microbiota mediates the physiological and metabolic changes observed during high-fat diet (HFD)-WPI consumption. C57BL/6J mice received a HFD containing WPI (HFD-WPI) or the control non-whey milk protein casein (HFD-CAS) for 5 or 10 weeks. HFD-fed mice supplemented with WPI showed reduced body weight gain, adiposity, Ob gene expression level in the epidydimal adipose tissue (eWAT) and plasma leptin relative to HFD-CAS-fed mice, after 5- or 10-weeks intervention both with or without ABX treatment. Following 10-weeks intervention, ABX and WPI had an additive effect in lowering adiposity and leptin availability. HFD-WPI-fed mice showed a decrease in the expression of genes encoding pro-inflammatory markers (MCP-1, TNFα and CD68) within the ileum and eWAT, compared to HFD-CAS-fed mice, without showing alterations following microbiota depletion. Additionally, WPI supplementation decreased HFD-induced intestinal permeability disruption in the distal ileum; an effect that was reversed by chronic ABX treatment. In summary, WPI reverses the effects of HFD on metabolic and physiological functions through mainly microbiota-independent mechanisms. Moreover, we demonstrate a protective effect of WPI on HFD-induced inflammation and ileal permeability disruption, with the latter being reversed by gut microbiota depletion.

Impact of food-derived bioactive peptides on gut function and health

The gastrointestinal tract (GIT) is the largest interface between our body and the environment. It is an organ system extending from the mouth to the anus and functions for food intake, digestion, transport and absorption of nutrients, meanwhile providing protection from environmental factors, like toxins, antigens, and pathogens. Diet is one of the leading factors modulating the function of the GIT. Bioactive peptides presenting naturally in food or derived from food proteins during digestion or processing have been revealed multifunctional in diverse biological processes, including maintaining gut health and function. This review summarizes the available evidence regarding the effects of food-derived bioactive peptides on gut function and health. Findings and insights from studies based on in vitro and animal models are discussed. The gastrointestinal mucosa maintains a delicate balance between immune tolerance to nutrients and harmful components, which is crucial for the digestive system's normal functions. Dietary bioactive peptides positively impact gastrointestinal homeostasis by modulating the barrier function, immune responses, and gut microbiota. However, there is limited clinical evidence on the safety and efficacy of bioactive peptides, much less on the applications of dietary peptides for the treatment or prevention of diseases related to the GIT. Further study is warranted to establish the applications of bioactive peptides in regulating gut health and function.

Tolerogenic Effect Elicited by Protein Fraction Derived From Different Formulas for Dietary Treatment of Cow's Milk Allergy in Human Cells

Several formulas are available for the dietary treatment of cow’s milk allergy (CMA). Clinical data suggest potentially different effect on immune tolerance elicited by these formulas. We aimed to comparatively evaluate the tolerogenic effect elicited by the protein fraction of different formulas available for the dietary treatment of CMA. Five formulas were compared: extensively hydrolyzed whey formula (EHWF), extensively hydrolyzed casein formula (EHCF), hydrolyzed rice formula (HRF), soy formula (SF), and amino acid-based formula (AAF). The formulas were reconstituted in water according to the manufacturer’s instructions and subjected to an in vitro infant gut simulated digestion using a sequential gastric and duodenal static model. Protein fraction was then purified and used for the experiments on non-immune and immune components of tolerance network in human enterocytes and in peripheral mononuclear blood cells (PBMCs). We assessed epithelial layer permeability and tight junction proteins (occludin and zonula occludens-1, ZO-1), mucin 5AC, IL-33, and thymic stromal lymphopoietin (TSLP) in human enterocytes. In addition, Th1/Th2 cytokine response and Tregs activation were investigated in PBMCs from IgE-mediated CMA infants. EHCF-derived protein fraction positively modulated the expression of gut barrier components (mucin 5AC, occludin and ZO-1) in human enterocytes, while SF was able to stimulate the expression of occludin only. EHWF and HRF protein fractions elicited a significant increase in TSLP production, while IL-33 release was significantly increased by HRF and SF protein fractions in human enterocytes. Only EHCF-derived protein fraction elicited an increase of the tolerogenic cytokines production (IL-10, IFN-γ) and of activated CD4+FoxP3+ Treg number, through NFAT, AP1, and Nf-Kb1 pathway. The effect paralleled with an up-regulation of FoxP3 demethylation rate. Protein fraction from all the study formulas was unable to induce Th2 cytokines production. The results suggest a different regulatory action on tolerogenic mechanisms elicited by protein fraction from different formulas commonly used for CMA management. EHCF-derived protein fraction was able to elicit tolerogenic effect through at least in part an epigenetic modulation of FoxP3 gene. These results could explain the different clinical effects observed on immune tolerance acquisition in CMA patients and on allergy prevention in children at risk for atopy observed using EHCF.

Interleukin-10 and Zonulin Are Associated With Postoperative Delayed Gastric Emptying in Critically Ill Surgical Pediatric Patients: A Prospective Pilot Study

BACKGROUND

Impaired gastric emptying (GE) is associated with morbidity in surgical critically ill children. The relationship between inflammation, gut barrier integrity (lipopolysaccharide binding protein [LBP]; zonulin), and GE has not been described in this cohort.

METHODS

Children ≥2 years of age and requiring critical care after surgery were enrolled. Preoperative and postoperative levels of serum cytokines, LBP, and zonulin, and GE by the acetaminophen absorption test, were measured, allowing patients to serve as their own controls. Postoperative delayed GE was defined as a decrease in GE by ≥20% compared with preoperative GE. The following were examined : comparison between postoperative andpreoperative values, correlations between fold change (postoperative/preoperative) in study variables, and fold change in study variables between patients with and without postoperative delayed GE.

RESULTS

Twenty patients, median age 14 years (12.25, 18), 12 female, were included. Eight of 20 patients had postoperative delayed GE. Postoperative interleukin-6 (IL-6), IL-8, IL-10, and LBP were increased, and zonulin was decreased (P-values < .05). Fold change in IL-10 and zonulin were inversely correlated (ρ -0.618, P = .004). Patients with postoperative delayed GE had greater fold increase in IL-10 (P = .0159) and fold decrease in zonulin (P = .0160). Five of 7 (71%) patients with both fold increase in IL-10 and decrease in zonulin had delayed GE.

CONCLUSION

Postoperative changes in IL-10 and zonulin were associated with delayed GE in surgical critically ill children, which might suggest a mechanism to for delayed GE in postoperative inflammation and gut barrier dysregulation after surgery.

Amelioration of Autoimmune Diabetes of NOD Mice by Immunomodulating Probiotics

Type 1 autoimmune diabetes is an autoimmune disease characterized by specific destruction of pancreatic β-cells producing insulin. Recent studies have shown that gut microbiota and immunity are closely linked to systemic immunity, affecting the balance between pro-inflammatory and regulatory immune responses. Altered gut microbiota may be causally related to the development of immune-mediated diseases, and probiotics have been suggested to have modulatory effects on inflammatory diseases and immune disorders. We studied whether a probiotic combination that has immunomodulatory effects on several inflammatory diseases can reduce the incidence of diabetes in non-obese diabetic (NOD) mice, a classical animal model of human T1D. When Immune Regulation and Tolerance 5 (IRT5), a probiotic combination comprising Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus reuteri, Bifidobacterium bifidium, and Streptococcus thermophiles, was administered 6 times a week for 36 weeks to NOD mice, beginning at 4 weeks of age, the incidence of diabetes was significantly reduced. Insulitis score was also significantly reduced, and β-cell mass was conversely increased by IRT5 administration. IRT5 administration significantly reduced gut permeability in NOD mice. The proportion of total regulatory T cells was not changed by IRT5 administration; however, the proportion of CCR9⁺ regulatory T (Treg) cells expressing gut-homing receptor was significantly increased in pancreatic lymph nodes (PLNs) and lamina propria of the small intestine (SI-LP). Type 1 T helper (Th1) skewing was reduced in PLNs by IRT5 administration. IRT5 could be a candidate for an effective probiotic combination, which can be safely administered to inhibit or prevent type 1 diabetes (T1D).

Maternal dietary uridine supplementation reduces diarrhea incidence in piglets by regulating the intestinal mucosal barrier and cytokine profiles

BACKGROUND

Nucleotides play an important role in the regulation of cellular energy and protein homeostasis, which facilitate the repair, recovery and repletion of tissue function. This study tested the effects of maternal uridine (UR) supplementation during late pregnancy and lactation of sows on the immune function of the small intestine in neonatal and suckling piglets.

RESULTS

Results showed that compared to the control group, maternal dietary UR supplementation significantly decreased incidence of diarrhea in suckling piglets (P < 0.01); and increased both duodenal and ileal average villus height (P < 0.01) as well as villus height/crypt depth in ileum (P = 0.017) in neonatal piglets. RT-qPCR results showed that maternal UR supplementation decreased mRNA expression of claudin-1 in jejunum and ileum of neonatal piglets (P < 0.05), while significantly increased mRNA expression of claudin-1 in duodenum and jejunum of suckling piglets. Furthermore, in suckling piglets, maternal dietary UR supplementation increased mRNA expression of IL-6, IL-8 and IL-1β in duodenum, jejunum and ileum (P < 0.05), increased IL-10 expression in both jejunal and ileal mucosa (P < 0.05) and increased mRNA expression of IKB and TLR4 in ileal mucosa (P < 0.05).

CONCLUSIONS

These results suggest that maternal dietary supplementation with UR contributed to reducing incidence of diarrhea by regulating cytokine secretion and intestinal mucosal barrier function in suckling piglets. © 2020 Society of Chemical Industry.

Intestinal Permeability in Children with Celiac Disease after the Administration of Oligofructose-Enriched Inulin into a Gluten-Free Diet-Results of a Randomized, Placebo-Controlled, Pilot Trial

Abnormalities in the intestinal barrier are a possible cause of celiac disease (CD) development. In animal studies, the positive effect of prebiotics on the improvement of gut barrier parameters has been observed, but the results of human studies to date remain inconsistent. Therefore, this study aimed to evaluate the effect of twelve-week supplementation of a gluten-free diet (GFD) with prebiotic oligofructose-enriched inulin (10 g per day) on the intestinal permeability in children with CD treated with a GFD. A pilot, randomized, placebo-controlled nutritional intervention was conducted in 34 children with CD, being on a strict GFD. Sugar absorption test (SAT) and the concentrations of intestinal permeability markers, such as zonulin, intestinal fatty acid-binding protein, claudin-3, calprotectin, and glucagon-like peptide-2, were measured. We found that the supplementation with prebiotic did not have a substantial effect on barrier integrity. Prebiotic intake increased excretion of mannitol, which may suggest an increase in the epithelial surface. Most children in our study seem to have normal values for intestinal permeability tests before the intervention. For individuals with elevated values, improvement in calprotectin and SAT was observed after the prebiotic intake. This preliminary study suggests that prebiotics may have an impact on the intestinal barrier, but it requires confirmation in studies with more subjects with ongoing leaky gut.

Depletion of the diabetic gut microbiota resistance enhances stem cells therapy in type 1 diabetes mellitus

Microbiome, considered as the "second genome" of the host, is altered in type 1 diabetes mellitus (T1DM) patients to a state of dysbiosis. Mesenchymal stem cell (MSC) transplantation is a promising treatment for T1DM but is limited by several factors in the diabetic host. In this study, we tested the hypothesis that dysbiotic gut microbiota may limit MSC therapy, and modulating gut microbiota may help to improve the effects of MSC transplantation. Methods: NOD/Ltj mice, treated with adipose-derived stem cells (ADSCs), were fed with an antibiotics cocktails (Abx) for 1 week. The blood glucose levels, insulitis, intestinal permeability and gut bacteria translocation to the pancreas were evaluated. 16s rRNA and colon tissue transcription sequencing were performed to analyze beneficial bacteria and reactive host biomolecules in the ADSCs+Abx group. Based on the sequencing results, specific bacteria were gavaged orally to diabetic mice to confirm their effect on ADSCs transplantation in T1DM was determined. Results: We found that the recolonized the diabetic gut microbiota abolished the therapeutic effect of ADSCs. On the contrary, depletion of the diabetic gut microbiota by antibiotics treatment in diabetic mice significantly enhanced the therapeutic effects of ADSCs as measured by reversal of hyperglycemia, insulitis, and increased insulin output. Mechanistically, treatment with antibiotics increased the abundance of Bifidobacterium in the gut and reduced bacterial translocation to the pancreas by promoting Mucin2 expression and thickening the mucus layer through TRPM7. The mechanism was confirmed the re-colonization of the gut by B.breve through oral gavage that produced similar results. Conclusions: These results provide the rationale for a new approach to improve MSC therapy for T1DM by altering the gut microbiota.

Evaluating the Causal Role of Gut Microbiota in Type 1 Diabetes and Its Possible Pathogenic Mechanisms

Type 1 diabetes (T1D) is a multifactorial autoimmune disease mediated by genetic, epigenetic, and environmental factors. In recent years, the emergence of high-throughput sequencing has allowed us to investigate the role of gut microbiota in the development of T1D. Significant changes in the composition of gut microbiome, also termed dysbiosis, have been found in subjects with clinical or preclinical T1D. However, whether the dysbiosis is a cause or an effect of the disease remains unclear. Currently, increasing evidence has supported a causal link between intestine microflora and T1D development. The current review will focus on recent research regarding the associations between intestine microbiome and T1D progression with an intention to evaluate the causality. We will also discuss the possible mechanisms by which imbalanced gut microbiota leads to the development of T1D.

Animal Models for Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGID), such as functional dyspepsia (FD) and irritable bowel syndrome (IBS) are characterized by chronic abdominal symptoms in the absence of an organic, metabolic or systemic cause that readily explains these complaints. Their pathophysiology is still not fully elucidated and animal models have been of great value to improve the understanding of the complex biological mechanisms. Over the last decades, many animal models have been developed to further unravel FGID pathophysiology and test drug efficacy. In the first part of this review, we focus on stress-related models, starting with the different perinatal stress models, including the stress of the dam, followed by a discussion on neonatal stress such as the maternal separation model. We also describe the most commonly used stress models in adult animals which brought valuable insights on the brain-gut axis in stress-related disorders. In the second part, we focus more on models studying peripheral, i.e., gastrointestinal, mechanisms, either induced by an infection or another inflammatory trigger. In this section, we also introduce more recent models developed around food-related metabolic disorders or food hypersensitivity and allergy. Finally, we introduce models mimicking FGID as a secondary effect of medical interventions and spontaneous models sharing characteristics of GI and anxiety-related disorders. The latter are powerful models for brain-gut axis dysfunction and bring new insights about FGID and their comorbidities such as anxiety and depression.

Response of broiler chickens to dietary soybean bioactive peptide and coccidia challenge

Growth performance, nutrient digestibility, jejunal morphology, plasma cytokine, and gene expression responses of broiler chickens (Cobb 500) to graded concentrations of dietary soybean bioactive peptide (SBP) and coccidia challenge (CC) were investigated in 2 experiments. In experiment 1, 384 male broiler chicks were used to investigate the effect of graded dietary concentrations of SBP on growth performance, nutrient digestibility, and intestinal morphology in a randomized complete block design with 8 replicate cages and 6 diets. Corn-soybean meal-based diet was supplemented with 0, 1, 2, 3, 4, and 5 g of SBP/kg of diet. There were linear effects (P < 0.05) of graded concentrations of SBP on BW, BW gain, gain:feed, ileal villus height, and jejunal crypt depth at day 22 post hatching. There were linear effects (P < 0.01) of graded SBP concentrations on Ileal DM and energy digestibility. Experiment 2 was conducted to investigate the immune-protective properties of SBP on broiler chickens during a coccidia challenge. A total of 256 male broiler chicks were randomly assigned to 8 replicate cages in a 2 × 2 factorial arrangement of treatments with 2 SBP levels (0 or 4 g/kg of diet) and with or without CC. On day 14 post hatching, birds in the challenged group received 20×, which is twice the recommended coccidia vaccine dose of 25 doses/kg BW, whereas the non-challenged group received physiological saline. Dietary SBP ameliorated the CC-induced effect (P = 0.01) on gain: feed. Coccidia challenge reduced (P < 0.05) jejunal villi height, whereas dietary SBP supplementation increased (P < 0.05) jejunal villi height. Dietary SBP attenuated the CC-induced effects (P < 0.05) on the expression of plasma IL-1β, transforming growth factor-β, claudin-1, and occludin genes. In conclusion, dietary SBP improved growth performance, nutrient digestibility, and jejunal morphology. In addition, dietary SBP reduced the impact of coccidia challenge, and may be beneficial in the feed of broiler chickens for alleviation of health-related effects of coccidia infection.

Effect of Prebiotic on Microbiota, Intestinal Permeability, and Glycemic Control in Children With Type 1 Diabetes

CONTEXT

Patients with type 1 diabetes (T1D) have lower microbiota diversity and distinct gut microbial profiles that have been linked to changes in intestinal permeability. Prebiotics are nondigestible carbohydrates that alter gut microbiota and could potentially improve glycemic control and reduce intestinal permeability and thereby insulin sensitivity.

OBJECTIVE

To determine the effect of prebiotics on glycemic control, gut microbiota, and intestinal permeability in children with T1D.

DESIGN

A randomized, placebo-controlled trial in children 8 to 17 years of age with T1D using placebo or prebiotic oligofructose-enriched inulin for 12 weeks. Baseline, 3-month, and 6-month assessments included HbA1c, C-peptide, gut microbiota, intestinal permeability, frequency of diabetic ketoacidosis (DKA), and severe hypoglycemia.

RESULTS

Forty-three subjects were randomized and 38 completed the study. The groups were similar at baseline: prebiotic (N = 17), age 12.5 years (SD of 2.8), HbA1c 8.02% (SD of 0.82); placebo (N = 21), age 12.0 years (SD of 2.6), HbA1c 8.08% (SD of 0.91). No significant differences were found in the frequency of DKA or severe hypoglycemia. At 3-months, C-peptide was significantly higher (P = 0.029) in the group who received prebiotics, which was accompanied by a modest improvement in intestinal permeability (P = 0.076). There was a significant increase in the relative abundance of Bifidobacterium within the prebiotic group at 3 months that was no longer present after the 3-month washout. The placebo group had significantly higher relative abundance of Streptococcus, Roseburia inulinivorans, Terrisporobacter, and Faecalitalea compared with the prebiotic group at 3 months.

CONCLUSION

Prebiotics are a potentially novel, inexpensive, low-risk treatment addition for T1D that may improve glycemic control. Further larger-scale trials are needed.

Probiotics for cow's milk protein allergy: a systematic review of randomized controlled trials

Cow's milk protein allergy (CMPA) is the commonest food allergy in infancy and is associated with significant health burden. Given their immune modulatory properties, probiotics have been proposed as a strategy for management of CMPA. We aimed to systematically review efficacy and safety of probiotics in the management of CMPA. Databases PubMed, EMBASE, CINAHL, Cochrane Central Library, and Google scholar were searched in August 2018 for randomized controlled trials (RCT) of probiotic supplementation as an adjunct in the management of infants with suspected/proven CMPA. Primary outcomes were resolution of hematochezia and acquisition of tolerance to CMP at 6, 12, 24, and 36 months. Secondary outcomes included effect on allergic symptoms (SCORAD index), growth, gut microbiota, and adverse effects. A total of 10 RCTs (n = 845; probiotics, 422; control, 423) with low to unclear risk of bias were included. Meta-analysis showed probiotic supplementation was not associated with earlier resolution of hematochezia (n = 87; RR: 1.45 (95% CI: 0.96-2.18), p = 0.08; level of evidence (LOE), very low), in presumed CMPA. In confirmed CMPA, probiotics were associated with higher rate of acquisition of tolerance to CMP at the end of 3 years compared with placebo (N = 493; RR, 1.47; 95% CI, (1.17-1.84); p = 0.0009; LOE, low]. Meta-analysis was not possible for other outcomes. There were no probiotic related adverse effects. Conclusion: Limited low-quality evidence indicates that probiotic supplementation may be associated with earlier acquisition of tolerance to CMP in children with CMPA. Large well-designed trials are essential to confirm these findings. What is Known: • Cow's milk protein allergy (CMPA) is one of the commonest food allergies in children. CMPA is associated with significant socioeconomic burden. • Elimination diet and extensively hydrolyzed formula is the mainstay of the management of CMPA. What is New: • This first systematic review of randomized controlled trials shows that probiotics as an adjuvant can lead to earlier acquisition of tolerance to CMP in children at 36 months of age. However, the evidence is low quality and influenced by data from one large study. • Probiotic supplementation was not associated with earlier resolution of hematochezia.

Colonic hypersensitivity and low-grade inflammation in a spontaneous animal model for functional gastrointestinal disorders

BACKGROUND

A complex interplay between a failing intestinal barrier and low-grade inflammation leading to sensorimotor disturbances is an often-cited mechanism in the pathogenesis of functional gastrointestinal disorders (FGID). However, the cause-consequence relationship between these features has not been clearly established. We previously described jejunal alterations in the normoglycemic BB-rat (BBDP-N) model proposing this model as a suitable animal model to study FGID pathophysiology. The current study explores colonic permeability, inflammation, and sensitivity of the BB-rat.

METHODS

Colonic tissue of BBDP-N and control (BBDR) rats at 50, 90, 110, 160, and 220 days (n ≥ 7 per group) was used to assess intestinal permeability in Ussing chambers and inflammation, including infiltration by eosinophils, mast cells, and eosinophil peroxidase (EPO) activity. Anxiety-like symptoms were evaluated at 50, 90, and 220 days and colonic sensitivity at 160 and 220 days by measuring the visceromotor response (VMR) to isobaric colorectal distensions.

KEYS RESULTS

Lamina propria eosinophil and mast cell infiltration and increased EPO activity were demonstrated from 90 days onward. Increased permeability and myenteric ganglionitis were observed in the oldest BBDP-N rats. At 220 days, the VMR was significantly increased suggesting colonic hypersensitivity. At the same age, increased anxiety-like behavior was observed.

CONCLUSION AND INFERENCES

We demonstrated a lamina propria eosinophil and mast cell infiltration preceding visceral hypersensitivity in the colon of the BBDP-N rat, reminiscent of patients with FGID. These findings help elucidating pathogenetic pathways in FGID and further validate the BBDP-N rat as an attractive model to study pathophysiology and therapy of FGID.

Cow's Milk Allergy: Immunomodulation by Dietary Intervention

Cow’s milk proteins cause allergic symptoms in 2% to 3% of all infants. In these individuals, the physiological mechanism of tolerance is broken with subsequent possible sensitization to antigens, which can lead eventually to allergic responses. The present review aims to provide an overview of different aspects of immune modulation by dietary intervention in cow’s milk allergy (CMA). It focuses on pathogenetic mechanisms of different CMA related disorders, e.g., gastroesophageal reflux and eosinophilic esophagitis, highlighting the role of dietary management on innate and adaptive immune systems. The traditional dietary management of CMA has greatly changed in the last years, moving from a passive approach, consisting of an elimination diet to relieve symptoms, to a “proactive” one, meaning the possibility to actively modulate the immune system. Thus, new insights into the role of hydrolysates and baked milk in immunomodulation are addressed here. Additionally, nutritional components, such as pre- and probiotics, may target the immune system via microbiota, offering a possible road map for new CMA prevention and treatment strategies.

Spatial variations in gut permeability are linked to type 1 diabetes development in non-obese diabetic mice

OBJECTIVES

To determine if spatial variations in gut permeability play a role in regulating type 1 diabetes (T1D) progression.

RESEARCH DESIGN AND METHODS

Spatially resolved duodenum, jejunum, ileum, and large intestine sections from end-stage T1D non-obese diabetic (NOD) mice were probed by immunohistochemistry to quantify zonulin levels as a measure of gut permeability in early-progressor and late-progressor NOD mice in comparison with non-progressor NOD mice and healthy NOR/LtJ control mice.

RESULTS

Zonulin levels were elevated in the small and large intestines in early-progressor and late-progressor NOD mice in comparison with non-progressor NOD mice and healthy NOR control mice. In early-onset mice, elevated zonulin levels were maximum in the duodenum and jejunum and decreased in the ileum and large intestine. In late-progressor mice, zonulin levels were elevated almost evenly along the small and large intestines. In non-progressor NOD mice, zonulin levels were comparable with NOR control levels in both the small and large intestines.

CONCLUSIONS

Elevated zonulin expression levels indicated that gut permeability was increased both in the small and large intestines in NOD mice that progressed to end-stage T1D in comparison with non-progressor NOD mice and healthy NOR control mice. Highest elevations in zonulin levels were observed in the duodenum and jejunum followed by the ileum and large intestines. Spatial variations in gut permeability appeared to play a role in regulating the rate and severity of T1D progression in NOD mice indicating that spatial variations in gut permeability should be investigated as a potentially important factor in human T1D progression.

The epithelial barrier-protecting properties of a soy hydrolysate

Enhancing the epithelial barrier function could be a possible strategy to prevent food allergy or reduce its symptoms. Soy hydrolysates containing bioactive peptides could be instrumental in this. In this study, the protective effects of pretreatment with 6 soy hydrolysates on calcium ionophore A23187-induced TEER reduction were studied in T84 cells. The effects of the most potent soy hydrolysate on tight junction gene expression were studied. In order to identify the underlying pathways involved, the barrier disruptor specificity of the effect was studied by comparing the protective effects on TEER and Lucifer Yellow flux after the exposure to barrier disruptors that work via different intracellular pathways, i.e. the disruptors A23187, mellitin, and deoxynivalenol (DON). Preincubation with one of the six hydrolysates protected the epithelial cells from a decrease in TEER induced by A23187 (restored to 105% of the starting point, while A23187 alone decreased to 53% of the starting value) and mellitin (restored to 11% of the starting point, while mellitin alone decreased to 3.8% of the starting value). This soy hydrolysate was found to increase claudin-1 and decrease claudin-2 expression. The protective effect of the hydrolysate on TEER was specific for the barrier disruptors A23187 and mellitin, but was not observed for DON. This observation suggests that the soy hydrolysate may act via PKC isoforms, which are known to lead to changes in the expression of claudin-1 and 2. Our data suggest that specific soy hydrolysates may be designed to strengthen the epithelial barrier which might be instrumental in the management of the barrier function in individuals at risk of developing food allergy.

Immunomodulatory Protein Hydrolysates and Their Application

Immunomodulatory protein hydrolysate consumption may delay or prevent western immune-related diseases. In order to purposively develop protein hydrolysates with an optimal and reproducible immunomodulatory effect, knowledge is needed on which components in protein hydrolysates are responsible for the immune effects. Important advances have been made on this aspect. Also, knowledge on mechanisms underlying the immune modulating effects is indispensable. In this review, we discuss the most promising application possibilities for immunomodulatory protein hydrolysates. In order to do so, an overview is provided on reported in vivo immune effects of protein hydrolysates in both local intestinal and systemic organs, and the current insights in the underlying mechanisms of these effects. Furthermore, we discuss current knowledge and physicochemical approaches to identify the immune active protein sequence(s). We conclude that multiple hydrolysate compositions show specific immune effects. This knowledge can improve the efficacy of existing hydrolysate-containing products such as sports nutrition, clinical nutrition, and infant formula. We also provide arguments for why immunomodulatory protein hydrolysates could be applied to manage the immune response in the increasing number of individuals with a higher risk of immune dysfunction due to, for example, increasing age or stress.

On the pathogenesis of insulin-dependent diabetes mellitus: the role of microbiota

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the selective destruction of insulin-producing β cells as result of a complex interplay between genetic, stochastic and environmental factors in genetically susceptible individuals. An increasing amount of experimental data from animal models and humans has supported the role played by imbalanced gut microbiome in T1D pathogenesis. The commensal intestinal microbiota is fundamental for several physiologic mechanisms, including the establishment of immune homeostasis. Alterations in its composition have been correlated to changes in the gut immune system, including defective tolerance to food antigens, intestinal inflammation and enhanced gut permeability. Early findings reported differences in the intestinal microbiome of subjects affected by prediabetes or overt disease compared to healthy individuals. The present review focuses on microbiota-host homeostasis, its alterations, factors that influence microbiome composition and discusses their putative correlation with T1D development. Further studies are necessary to clarify the role played by microbiota modifications in the processes that cause enhanced permeability and the autoimmune mechanisms responsible for T1D onset.

Precision medicine in cow's milk allergy: proteomics perspectives from allergens to patients

Cow's milk allergy (CMA) is one of the most common food allergies, especially during childhood. CMA is an immunological mediated adverse reaction to one or more cow's milk proteins, which are normally harmless to a non-allergic individual, as the result of a failure of oral tolerance. To make a correct diagnosis of CMA and a proper treatment is critical in clinical practice. Application of proteomics along with new bio-informatics tools in the field of food allergy is one of the hot topics presented in recent years. In the present review, we focus on recent applications of proteomics to the field of cow's milk allergy, from allergens quantification to the diagnosis, treatment and prognosis. Furthermore, we also shed a light on potential future directions and developments, that are parts of personalized medicine but also of the One Health approach.

SIGNIFICANCE

The field of food allergies is becoming a milestone in public health. Food allergies, in fact, can cause life-threatening reactions and profoundly influence the quality of life. Precise, fast and reliable diagnosis of food allergies, and in particular milk allergies is essential to avoid severe allergic reactions and also to prevent dangerous and eventually unnecessary dietary restrictions; but this can be difficult also due to a complex interaction of genetic background, environment, and microbiota. In this sense, proteomics represents steps toward researching food and milk allergy integrated with the clinic to improve pathophysiology, diagnosis, therapy, and prognosis.

Modulation of the diet and gastrointestinal microbiota normalizes systemic inflammation and β-cell chemokine expression associated with autoimmune diabetes susceptibility

Environmental changes associated with modern lifestyles may underlie the rising incidence of Type 1 diabetes (T1D). Our previous studies of T1D families and the BioBreeding (BB) rat model have identified a peripheral inflammatory state that is associated with diabetes susceptibility, consistent with pattern recognition receptor ligation, but is independent of disease progression. Here, compared to control strains, islets of spontaneously diabetic BB DRlyp/lyp and diabetes inducible BB DR+/+ weanlings provided a standard cereal diet expressed a robust proinflammatory transcriptional program consistent with microbial antigen exposure that included numerous cytokines/chemokines. The dependence of this phenotype on diet and gastrointestinal microbiota was investigated by transitioning DR+/+ weanlings to a gluten-free hydrolyzed casein diet (HCD) or treating them with antibiotics to alter/reduce pattern recognition receptor ligand exposure. Bacterial 16S rRNA gene sequencing revealed that these treatments altered the ileal and cecal microbiota, increasing the Firmicutes:Bacteriodetes ratio and the relative abundances of lactobacilli and butyrate producing taxa. While these conditions did not normalize the inherent hyper-responsiveness of DR+/+ rat leukocytes to ex vivo TLR stimulation, they normalized plasma cytokine levels, plasma TLR4 activity levels, the proinflammatory islet transcriptome, and β-cell chemokine expression. In lymphopenic DRlyp/lyp rats, HCD reduced T1D incidence, and the introduction of gluten to this diet induced islet chemokine expression and abrogated protection from diabetes. Overall, these studies link BB rat islet-level immunocyte recruiting potential, as measured by β-cell chemokine expression, to a genetically controlled immune hyper-responsiveness and innate inflammatory state that can be modulated by diet and the intestinal microbiota.

Immunomodulating peptides for food allergy prevention and treatment

Among the most promising strategies currently assayed against IgE-mediated allergic diseases stands the possibility of using immunomodulating peptides to induce oral tolerance toward offending food allergens or even to prevent allergic sensitization. This review focuses on the beneficial effects of food derived immunomodulating peptides on food allergy, which can be directly exerted in the intestinal tract or once being absorbed through the intestinal epithelial barrier to interact with immune cells. Food peptides influence intestinal homeostasis by maintaining and reinforcing barrier function or affecting intestinal cell-signalling to nearby immune cells and mucus secretion. In addition, they can stimulate cells of the innate and adaptive immune system while supressing inflammatory responses. Peptides represent an attractive alternative to whole allergens to enhance the safety and efficacy of immunotherapy treatments. The conclusions drawn from curative and preventive experiments in murine models are promising, although there is a need for more pre-clinical studies to further explore the immunomodulating strategy and its mechanisms and for a deeper knowledge of the peptide sequence and structural requirements that determine the immunoregulatory function.

Extensively hydrolyzed casein formula alone or with L. rhamnosus GG reduces β-lactoglobulin sensitization in mice

BACKGROUND

Extensively hydrolyzed casein formula (EHCF) has been proposed for the prevention and is commonly used for the treatment of cow's milk allergy (CMA). The addition of the probiotic Lactobacillus rhamnosus GG (LGG) to EHCF may induce faster acquisition of tolerance to cow's milk. The mechanisms underlying this effect are largely unexplored. We investigated the effects of EHCF alone or in combination with LGG on β-lactoglobulin (BLG) sensitization in mice.

METHODS

Three-week-old C3H/HeOuJ mice were sensitized by oral administration of BLG using cholera toxin as adjuvant at weekly intervals for 5 weeks (sensitization period). Two experimental phases were conducted: (i) EHCF or EHCF+LGG given daily, starting 2 weeks before the sensitization period and then given daily for 5 weeks and (ii) EHCF or EHCF+LGG given daily for 4 weeks, starting 1 week after the sensitization period. Diet free of cow's milk protein was used as control. Acute allergic skin response, anaphylactic symptom score, body temperature, intestinal permeability, anti-BLG serum IgE, and interleukin (IL)-4, IL-5, IL-10, IL-13, IFN-γ mRNA expression were analyzed. Peptide fractions of EHCF were characterized by reversed-phase (RP)-HPLC, MALDI-TOF mass spectrometry, and nano-HPLC/ESI-MS/MS.

RESULTS

Extensively hydrolyzed casein formula administration before or after BLG-induced sensitization significantly reduced acute allergic skin reaction, anaphylactic symptom score, body temperature decrease, intestinal permeability increase, IL-4, IL-5, IL-13, and anti-BLG IgE production. EHCF increased expression of IFN-γ and IL-10. Many of these effects were significantly enhanced by LGG supplementation. The peptide panels were similar between the two study formulas and contained sequences that could have immunoregulatory activities.

CONCLUSIONS

The data support dietary intervention with EHCF for CMA prevention and treatment through a favorable immunomodulatory action. The observed effects are significantly enhanced by LGG supplementation.

Specific inulin-type fructan fibers protect against autoimmune diabetes by modulating gut immunity, barrier function, and microbiota homeostasis

SCOPE

Dietary fibers capable of modifying gut barrier and microbiota homeostasis affect the progression of type 1 diabetes (T1D). Here, we aim to compare modulatory effects of inulin-type fructans (ITFs), natural soluble dietary fibers with different degrees of fermentability from chicory root, on T1D development in nonobese diabetic mice.

METHODS AND RESULTS

Female nonobese diabetic mice were weaned to long- and short-chain ITFs [ITF(l) and ITF(s), 5%] supplemented diet up to 24 weeks. T1D incidence, pancreatic-gut immune responses, gut barrier function, and microbiota composition were analyzed. ITF(l) but not ITF(s) supplementation dampened the incidence of T1D. ITF(l) promoted modulatory T-cell responses, as evidenced by increased CD25⁺ Foxp3⁺ CD4⁺ regulatory T cells, decreased IL17A⁺ CD4⁺ Th17 cells, and modulated cytokine production profile in the pancreas, spleen, and colon. Furthermore, ITF(l) suppressed NOD like receptor protein 3 caspase-1-p20-IL-1β inflammasome in the colon. Expression of barrier reinforcing tight junction proteins occludin and claudin-2, antimicrobial peptides β-defensin-1, and cathelicidin-related antimicrobial peptide as well as short-chain fatty acid production were enhanced by ITF(l). Next-generation sequencing analysis revealed that ITF(l) enhanced Firmicutes/Bacteroidetes ratio to an antidiabetogenic balance and enriched modulatory Ruminococcaceae and Lactobacilli.

CONCLUSION

Our data demonstrate that ITF(l) but not ITF(s) delays the development of T1D via modulation of gut-pancreatic immunity, barrier function, and microbiota homeostasis.

Higher Levels of Serum Zonulin May Rather Be Associated with Increased Risk of Obesity and Hyperlipidemia, Than with Gastrointestinal Symptoms or Disease Manifestations

Zonulin is considered a biomarker of increased intestinal permeability, and elevated levels have been found in celiac disease. The primary aim of this study was to examine the association between serum zonulin levels and gastrointestinal (GI) symptoms, and secondarily, between zonulin levels and anthropometric and metabolic factors. The offspring (n = 363) of the participants of the Malmö Diet and Cancer cardiovascular cohort (MDC-CV) were invited to an anthropometric and clinical examination, where fasting plasma glucose levels were measured. Questionnaires about lifestyle factors and medical history were completed along with the Visual Analog Scale for Irritable Bowel Syndrome (VAS-IBS). Zonulin levels were measured in serum by ELISA. Neither GI symptoms nor GI diseases had any influence on zonulin levels. Higher zonulin levels were associated with higher waist circumference (p = 0.003), diastolic blood pressure (p = 0.003), and glucose levels (p = 0.036). Higher zonulin levels were associated with increased risk of overweight (p < 0.001), obesity (p = 0.047), and hyperlipidemia (p = 0.048). We cannot detect altered zonulin levels among individuals reporting GI symptoms or GI diseases, but higher zonulin levels are associated with higher waist circumference, diastolic blood pressure, fasting glucose, and increased risk of metabolic diseases.

Is there a role for gut microbiota in type 1 diabetes pathogenesis?

Type 1 diabetes mellitus (T1D) is an autoimmune disease characterized by insufficient insulin production due to the destruction of insulin secreting β-cells in the Langerhans islets. A variety of factors, including chemicals, viruses, commensal bacteria and diet have been proposed to contribute to the risk of developing the disorder. In the last years, gut microbiota has been proposed as a main factor in T1D pathogenesis. Several alterations of gut microbiota composition were described both in animal model and in humans. The decrease of Firmicutes/Bacteroides ratio was the most frequent pattern described, in particular, in human studies. Furthermore, Bacteroides, Clostridium cluster XIVa, Lactobacillus, Bifidobacterium, and Prevotella relative abundances were different in healthy and affected subjects. Dysbiosis would seem to increase intestinal permeability and thus promote the development of a pro-inflammatory niche that stimulates β-cell autoimmunity in predisposed subjects. Preliminary studies on animal models were realized to investigate the role of gut microbiota modulation as therapy or prevention approach in predisposed animals: promising and stimulating results have been reported. Key message Dietary antigens and microbiota-derived products might act as triggers of T1D by causing a pro-inflammatory and metabolic dysfunctional environment.

Where genes meet environment-integrating the role of gut luminal contents, immunity and pancreas in type 1 diabetes

The rise in new cases of type 1 diabetes (T1D) in genetically susceptible individuals over the past half century has been attributed to numerous environmental "triggers" or promoters such as enteroviruses, diet, and most recently, gut bacteria. No single cause has been identified in humans, likely because there are several pathways by which one can develop T1D. There is renewed attention to the role of the gut and its immune system in T1D pathogenesis based largely on recent animal studies demonstrating that altering the gut microbiota affects diabetes incidence. Although T1D patients display dysbiosis in the gut microbiome, it is unclear whether this is cause or effect. The heart of this question involves several moving parts including numerous risk genes, diet, viruses, gut microbiota, timing, and loss of immune tolerance to β-cells. Most clinical trials have addressed only one aspect of this puzzle using some form of immune suppression, without much success. The key location where our genes meet and deal with the environment is the gastrointestinal tract. The influence of all of its major contents, including microbes, diet, and immune system, must be understood as part of the integrative biology of T1D before we can develop durable means of preventing, treating, or curing this disease. In the present review, we expand our previous gut-centric model based on recent developments in the field.

Zonulin, a regulator of epithelial and endothelial barrier functions, and its involvement in chronic inflammatory diseases

Beside digesting nutrients and absorbing solutes and electrolytes, the intestinal epithelium with its barrier function is in charge of a tightly controlled antigen trafficking from the intestinal lumen to the submucosa. This trafficking dictates the delicate balance between tolerance and immune response causing inflammation. Loss of barrier function secondary to upregulation of zonulin, the only known physiological modulator of intercellular tight junctions, leads to uncontrolled influx of dietary and microbial antigens. Additional insights on zonulin mechanism of action and the recent appreciation of the role that altered intestinal permeability can play in the development and progression of chronic inflammatory disorders has increased interest of both basic scientists and clinicians on the potential role of zonulin in the pathogenesis of these diseases. This review focuses on the recent research implicating zonulin as a master regulator of intestinal permeability linked to the development of several chronic inflammatory disorders.

Dietary metabolites and the gut microbiota: an alternative approach to control inflammatory and autoimmune diseases

It is now convincingly clear that diet is one of the most influential lifestyle factors contributing to the rise of inflammatory diseases and autoimmunity in both developed and developing countries. In addition, the modern 'Western diet' has changed in recent years with increased caloric intake, and changes in the relative amounts of dietary components, including lower fibre and higher levels of fat and poor quality of carbohydrates. Diet shapes large-bowel microbial ecology, and this may be highly relevant to human diseases, as changes in the gut microbiota composition are associated with many inflammatory diseases. Recent studies have demonstrated a remarkable role for diet, the gut microbiota and their metabolites-the short-chain fatty acids (SCFAs)-in the pathogenesis of several inflammatory diseases, such as asthma, arthritis, inflammatory bowel disease, colon cancer and wound-healing. This review summarizes how diet, microbiota and gut microbial metabolites (particularly SCFAs) can modulate the progression of inflammatory diseases and autoimmunity, and reveal the molecular mechanisms (metabolite-sensing G protein-coupled receptor (GPCRs) and inhibition of histone deacetylases (HDACs)). Therefore, considerable benefit could be achieved simply through the use of diet, probiotics and metabolites for the prevention and treatment of inflammatory diseases and autoimmunity.

Whey protein concentrate enhances intestinal integrity and influences transforming growth factor-β1 and mitogen-activated protein kinase signalling pathways in piglets after lipopolysaccharide challenge

Whey protein concentrate (WPC) has been reported to have protective effects on the intestinal barrier. However, the molecular mechanisms involved are not fully elucidated. Transforming growth factor-β1 (TGF-β1) is an important component in the WPC, but whether TGF-β1 plays a role in these processes is not clear. The aim of this study was to investigate the protective effects of WPC on the intestinal epithelial barrier as well as whether TGF-β1 is involved in these protection processes in a piglet model after lipopolysaccharide (LPS) challenge. In total, eighteen weanling pigs were randomly allocated to one of the following three treatment groups: (1) non-challenged control and control diet; (2) LPS-challenged control and control diet; (3) LPS+5 %WPC diet. After 19 d of feeding with control or 5 %WPC diets, pigs were injected with LPS or saline. At 4 h after injection, pigs were killed to harvest jejunal samples. The results showed that WPC improved (P<0·05) intestinal morphology, as indicated by greater villus height and villus height:crypt depth ratio, and intestinal barrier function, which was reflected by increased transepithelial electrical resistance and decreased mucosal-to-serosal paracellular flux of dextran (4 kDa), compared with the LPS group. Moreover, WPC prevented the LPS-induced decrease (P<0·05) in claudin-1, occludin and zonula occludens-1 expressions in the jejunal mucosae. WPC also attenuated intestinal inflammation, indicated by decreased (P<0·05) mRNA expressions of TNF-α, IL-6, IL-8 and IL-1β. Supplementation with WPC also increased (P<0·05) TGF-β1 protein, phosphorylated-Smad2 expression and Smad4 and Smad7 mRNA expressions and decreased (P<0·05) the ratios of the phosphorylated to total c-jun N-terminal kinase (JNK) and p38 (phospho-JNK:JNK and p-p38:p38), whereas it increased (P<0·05) the ratio of extracellular signal-regulated kinase (ERK) (phospho-ERK:ERK). Collectively, these results suggest that dietary inclusion of WPC attenuates the LPS-induced intestinal injury by improving mucosal barrier function, alleviating intestinal inflammation and influencing TGF-β1 canonical Smad and mitogen-activated protein kinase signalling pathways.

The normoglycaemic biobreeding rat: a spontaneous model for impaired gastric accommodation

OBJECTIVE

Impaired gastric accommodation is reported in patients with functional dyspepsia (FD). Previous findings in postinfectious patients with FD suggest that low-grade inflammation and dysfunction of nitrergic nerves play a role in impaired accommodation. To date, spontaneous animal models to study the relationship between these changes are lacking. We hypothesise that the normoglycaemic BioBreeding diabetes-prone (BB-DP) rat provides an animal model of inflammation-induced impaired gastric motor function.

DESIGN

Control diabetes-resistant biobreeding, normoglycaemic and hyperglycaemic BB-DP rats were sacrificed at the age of 30, 70 and 220 days and gastric fundus tissue was harvested to study nitrergic motor control, inflammation and expression of neuronal isoform of nitric oxide synthase (nNOS) and inducible isoform of nitric oxide synthase (iNOS). Nutrient-induced changes in intragastric pressure (IGP) were measured in normoglycaemic BB-DP rats to study accommodation.

RESULTS

No differences in nitrergic function and inflammation were observed between BB-DP and control rats at 30 days. The nitrergic component of the fundic muscle relaxation was reduced in BB-DP rats of 70 and 220 days. This was accompanied by a significant loss of nNOS proteins. IGP significantly increased during nutrient infusion in BB-DP rats of 220 days, indicating impaired accommodation. Infiltration of polymorphonuclear cells, increased myeloperoxidase activity and increased expression of iNOS was observed in the fundic mucosa and muscularis propria of 70-day-old and 220-day-old BB-DP rats.

CONCLUSIONS

BB-DP rats of 220 days display altered fundic motor control and impaired accommodation, which is least partially explained by loss of nitrergic function. This may be related to inflammatory changes in the neuromuscular layer, suggesting that normoglycaemic BB-DP rats provide a spontaneous model for inflammation-induced impaired gastric accommodation.