Continuous ingestion of sodium chloride solution promotes allergen absorption and may exacerbate allergy symptoms on ovalbumin-induced food allergy in mice

Various studies have reported relationships between salt intake and diseases, such as hypertension, cardiovascular disease, stroke, gastric cancer, and bronchial asthma. However, no reports exist on the relationship between salt intake and food allergies. In this study, we investigated the effect of continuous ingestion of sodium chloride (NaCl) on allergy symptoms using a mouse model of food allergy. BALB/c mice were divided into four groups of 6-8 animals each. The control-water group (CW) and sensitization-water group (SW) groups were provided free access to water, and the control-1% NaCl group (CS) and sensitization-1% NaCl group (SS) groups were provided a 1% NaCl solution. The SW and SS groups were sensitized with 50 µg ovalbumin (OVA) at 2 timepoints by intraperitoneal injection. After oral administration of OVA, anaphylactic response was measured and blood was collected. The mice were sacrificed, and serum levels of OVA and anti-OVA immunoglobulin (Ig)E and IgG1 were measured by enzyme-linked immunosorbent assays. The sodium ion (Na⁺) concentrations in duodenal and jejunal extracts were measured using a Na⁺ ion meter. The results suggested that continuous ingestion of a 1% NaCl solution for 36 days promoted allergen absorption and may have aggravated allergy symptoms in the mice. However, NaCl ingestion did not affect Na⁺ concentrations in the small intestine or OVA-specific antibody production.

A Murine Model of Food Allergy by Epicutaneous Adjuvant-Free Allergen Sensitization Followed by Oral Allergen Challenge Combined with Aspirin for Enhanced Detection of Hypersensitivity Manifestations and Immunotherapy Monitoring

Food allergy is one of the major existing health problems, but no effective treatment is available. In the current work, a murine model that closely mimics pathogenesis of human food allergy and its quantifiable diagnostic parameter design, even for mild hypersensitivity reactions, were established. BALB/c mice were epicutaneously sensitized with 1 mg chicken egg ovomucoid (OVM) or cow's milk casein, free of adjuvants, five times a week for two consecutive weeks. Eleven days later, allergen-specific IgG1 and IgE in serum were measured by ELISA. On day 25, 20 mg OVM or 12 mg α-casein was administered orally, and allergic reactions such as the fall in rectal temperature, symptom scores during 90-120 min, serum mast cell protease-1 and cytokine levels were monitored. The detection of mild allergic reactions due to adjuvant-free allergen sensitization and oral allergen challenge routes was amplified by the combination of oral allergen and aspirin administration simultaneously or aspirin administration within 15-30 min before an allergen challenge. Quantification of the maximum symptom score and the frequency of symptoms during the monitoring period improved evaluation accuracy of food allergy signals. Based on these results, efficacy of casein oral immunotherapy for cow's milk allergies, which are generally difficult to detect, was monitored adequately.

Psychological Stress Exacerbates Inflammation of the Ileum via the Corticotropin-Releasing Hormone-Mast Cell Axis in a Mouse Model of Eosinophilic Enteritis

The effects of psychological stress on eosinophilic gastrointestinal disorders have not been elucidated. This study investigated the effects of psychological stress in a mouse model of eosinophilic enteritis (EoN). BALB/c mice were treated with ovalbumin (OVA) to create an EoN model and subjected to either water avoidance stress (WAS) or sham stress (SS). Microscopic inflammation, eosinophil and mast cell counts, mRNA expression, and protein levels of type 2 helper T cell (Th2) cytokines in the ileum were compared between groups. We evaluated ex vivo intestinal permeability using an Ussing chamber. A corticotropin-releasing hormone type 1 receptor (CRH-R1) antagonist was administered before WAS, and its effects were analyzed. WAS significantly increased diarrhea occurrence and, eosinophil and mast cell counts, and decreased the villus/crypt ratio compared to those in the SS group. The mRNA expression of CRH, interleukin IL-4, IL-5, IL-13, eotaxin-1, and mast cell tryptase β2 significantly increased, and the protein levels of IL-5, IL-13, and OVA-specific immunoglobulin E (IgE) also significantly increased in the WAS group. Moreover, WAS significantly increased the intestinal permeability. The CRH-R1 antagonist significantly inhibited all changes induced by WAS. Psychological stress exacerbated ileal inflammation via the CRH-mast cell axis in an EoN mouse model.

Antioxidant Stress and Anti-Inflammatory Activities of Egg White Proteins and Their Derived Peptides: A Review

Oxidative stress and chronic inflammation are the common pathological bases of chronic diseases such as atherosclerosis, cancer, and cardiovascular diseases, but most of the treatment drugs for chronic diseases have side effects. There is an increasing interest to identify food-derived bioactive compounds that can mitigate the pathological pathways associated with oxidative stress and chronic inflammation. Egg white contain a variety of biologically active proteins, many of which have antioxidant and anti-inflammatory activities and usually show better activity after enzymatic hydrolysis. This review covers the antioxidative stress and anti-inflammatory activities of egg white proteins and their derived peptides and clarifies their mechanism of action in vivo and in vitro. In addition, the link between oxidative stress and inflammation as well as their markers are reviewed. It suggests the potential application of egg white proteins and their derived peptides and puts forward further research prospects.

Dairy-Derived and Egg White Proteins in Enhancing Immune System Against COVID-19

Coronavirus disease (COVID-19) is a global health challenge, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) triggers a plethora of respiratory disturbances and even multiple organs failure that can be fatal. Nutritional intervention is one of the key components toward to a proper management of COVID-19 patients, especially in those requiring medication, and should thus be considered the first-line treatment. Immuno-modulation and -stimulation are currently being explored in COVID-19 management and are gaining interest by food and pharmaceutical industries. Various dietary combinations, bioactive components, nutrients and fortified foods have been reported to modulate inflammation during disease progression. Dietary combinations of dairy-derived products and eggs are gaining an increasing attention given the huge immunomodulatory and anti-inflammatory properties attributed to some of their chemical constituents. Eggs are complex dietary components containing many essential nutrients and bioactive compounds as well as a high-quality proteins. Similarly, yogurts can replenish beneficial bacteria and contains macronutrients capable of stimulating immunity by enhancing cell immunity, reducing oxidative stress, neutralizing inflammation and regulating the intestinal barriers and gut microbiome. Thus, this review highlights the impact of nutritional intervention on COVID-19 management, focusing on the immunomodulatory and inflammatory effects of immune-enhancing nutrients.

Aspirin enhances sensitization to the egg-white allergen ovalbumin in rats

Enhancement of oral absorption of food allergens by non-steroidal anti-inflammatory drugs (NSAIDs), especially aspirin, is considered an exacerbating factor in the development of food allergies. In this study, we examined the effect of aspirin on oral sensitization to and absorption of the egg-white allergen ovalbumin (OVA) in rats. The absorption of OVA was evaluated by measuring the plasma concentration of OVA after oral administration by gavage. To evaluate oral sensitization to OVA, plasma levels of immunoglobulin (Ig) E and IgG₁ antibodies (Abs) specific to OVA were determined by enzyme-linked immunosorbent assay after initiation of sensitization. High-dose aspirin (30 mg/kg) increased oral OVA absorption and plasma levels of OVA-specific IgE and IgG₁ Abs compared with those observed in vehicle-treated rats. In contrast, low-dose aspirin (3 mg/kg) exerted no changes in either absorption or sensitization. Spermine, an absorption enhancer, increased the oral absorption of OVA to nearly the same extent as high-dose aspirin, whereas the plasma levels of OVA-specific IgE and IgG₁ Abs exhibited no significant differences between spermine- and vehicle-treated rats. Among the NSAIDs, diclofenac and indomethacin increased sensitization to OVA, similar to high-dose aspirin, but meloxicam exerted no effects on Ab levels. In conclusion, we showed that high-dose aspirin enhanced oral sensitization to OVA. Our study suggests that enhanced oral sensitization to OVA cannot be ascribed to increased absorption of OVA from the intestinal tract. Although the mechanisms underlying this enhancement of sensitization are still controversial, our study suggests that modification of cytokine production due to impairment of the intestinal barrier function and inhibition of cyclooxygenase-1 activity by aspirin may be involved.

Digestibility in the gastrointestinal tract and migration to blood of β'-component (Onk k 5), a major salmon roe IgE-binding protein

The major allergen of chum salmon (Oncorhynchus keta) roe is the β'-component (Onc k 5, β'-c), which is a yolk protein and a fragment of vitellogenin. When yolk content containing β'-c was orally administered to mice, β'-c passed through the gastrointestinal tract and was excreted in feces without marked degradation. The direct administration of β'-c to ligated jejunal and ileal loops showed that β'-c was absorbed through the small intestine and transferred into the blood. Immunohistochemical staining showed that orally administered β'-c was distributed from the apical side to the basal side of intestinal epithelial cells, suggesting that endocytosis may be involved in the intestinal absorption of β'-c. In conclusion, β'-c is absorbed along a large portion of the small intestine and circulates in the blood stream without significant digestion. The resistance of β'-c to gastrointestinal digestion seems to contribute to its strong allergenicity.

Intestinal absorption of the wheat allergen gliadin in rats

BACKGROUND

Aspirin enhances food allergy symptoms by increasing absorption of ingested allergens. The objective of this study is to elucidate the role of aspirin in facilitating intestinal absorption of the wheat allergen, gliadin, in rats.

METHODS

Plasma concentrations of gliadin were determined after oral administration by gavage or administration into a closed intestinal loop in rats. We used an in situ intestinal re-circulating perfusion experiment to examine the effect of pepsin on aspirin-facilitated gliadin absorption. Fluorescein isothiocyanate (FITC)-labeled dextran-40 (FD-40) was used as a marker of non-specific absorption. The molecular size of gliadin and its allergenicity in plasma were examined using immunoblot analysis and intradermal reaction tests with Evans blue dye (EBD) extravasation, respectively.

RESULTS

Aspirin increased plasma concentrations of gliadin after oral administration but had no effect in the closed intestinal loop study. An in situ intestinal re-circulating perfusion study showed that FITC-labeled gliadin was absorbed similarly to FD-40. Aspirin increased absorption of both intact and pepsin-digested gliadin, with a more significant effect on absorption of pepsin-treated gliadin. Immunoblotting showed that most gliadin was absorbed in intact form. When the gliadin fraction was extracted from rat plasma after gavage and injected intradermally into gliadin-sensitized rats, EBD extravasation was observed at injection sites in a gliadin dose-dependent manner.

CONCLUSIONS

Aspirin increased the absorption of intact and pepsin-digested gliadin via the paracellular pathway, maintaining their allergenicity. Moreover, the effect of aspirin on gliadin absorption was enhanced by modification and digestion of gliadin in the stomach.

Allergic reactions to milk appear sooner than reactions to hen's eggs: a retrospective study

BACKGROUND

Oral food challenge test doses are recommended to be performed at least 20 min apart; however, the times of symptom provocation from the start of the oral food challenge have never been compared between different foods. In this study, the durations from the start of the oral food challenge to symptom development in children with egg or milk allergy were compared.

METHODS

Thirty-eight and 74 children who had previously passed oral food challenges to 96 g of yogurt and pumpkin cake containing ¼ whole egg underwent oral food challenges with 200 mL raw cow's milk and 1 whole scrambled egg, respectively; of these, 15/38 and 33/74 children had a reaction.

RESULTS

The median ages of patients with a positive challenge were 5.8 and 5.1 years for milk and eggs, respectively. The median times for the first symptom occurrence were 20 min (range, 5-55 min) and 50 min (5-480 min), respectively (p = 0.009). The first symptoms developed within 30, 60, and 90 min in 12/15 (80 %), 15/15 (100 %), and 15/15 (100 %) children with milk allergies, and in 10/33 (30.3 %), 20/33 (60.6 %), and 26/33 (78.8 %) children with egg allergies, respectively. The median times of peak symptoms were 50 min (10-210 min) and 120 min (30-560 min) (p = 0.001), and those of symptom disappearance were 90 min (30-240 min) and 180 min (80-700 min) for milk and eggs (p = 0.002), respectively.

DISCUSSION

Based on the results of our study, symptoms developed within 30 min for only a subset of patients for eggs, and may even take upwards of 60 min to develop. The times of symptom disappearance were 90 min and 180 min for milk and eggs, respectively, indicating that egg-allergic patients should be observed for a longer period time than milk-allergic patients.

CONCLUSIONS

Allergic reactions induced by milk appeared and disappeared sooner than those induced by eggs.

Assessment of the Intestinal Barrier with Five Different Permeability Tests in Healthy C57BL/6J and BALB/cJ Mice

BACKGROUND

Intestinal permeability is thought to be of major relevance for digestive and nutrition-related diseases, and therefore has been studied in numerous mouse models of disease. However, it is unclear which tools are the preferable ones, and how normal values should be defined.

AIMS

To compare different in vivo permeability tests in healthy mice of commonly used genetic backgrounds.

METHODS

We assessed the intestinal barrier in male and female C57BL/6J and BALB/cJ mice of different ages, using four orally administered permeability markers, FITC-dextran 4000 (FITC-D4000) and ovalbumin (OVA) measured in plasma, and polyethylene glycol (PEG) and lactulose/mannitol (Lac/Man) measured in urine, and by assessing lipopolysaccharide (LPS) in portal vein plasma.

RESULTS

After gavage, FITC-D4000, OVA, Lac/Man, and PEG400, but not PEG4000, were detectable in plasma or urine. Female mice tended to have a higher permeability according to the FITC-D4000, OVA, and PEG400 tests, but the Lac/Man ratio was higher in males. No significant differences between the two mouse strains of young and old mice were observed except for mannitol recovery, which was higher in BALB/cJ mice compared to C57BL/6J mice (p < 0.05). Virtually no LPS was detected in healthy mice. For all markers, normal values have been defined based on 5th-95th percentile ranges of our data.

CONCLUSION

Selected oral permeability tests, such as FITC-D4000, OVA, PEG400, and Lac/Man, as well as LPS measurements in portal vein plasma, could be suitable for the evaluation of the intestinal barrier in mice, if used in a standardized way.

Common food allergens and their IgE-binding epitopes

Food allergy is an adverse immune response to certain kinds of food. Although any food can cause allergic reactions, chicken egg, cow's milk, wheat, shellfish, fruit, and buckwheat account for 75% of food allergies in Japan. Allergen-specific immunoglobulin E (IgE) antibodies play a pivotal role in the development of food allergy. Recent advances in molecular biological techniques have enabled the efficient analysis of food allergens. As a result, many food allergens have been identified, and their molecular structure and IgE-binding epitopes have also been identified. Studies of allergens have demonstrated that IgE antibodies specific to allergen components and/or the peptide epitopes are good indicators for the identification of patients with food allergy, prediction of clinical severity and development of tolerance. In this review, we summarize our current knowledge regarding the allergens and IgE epitopes in the well-researched allergies to chicken egg, cow's milk, wheat, shrimp, and peanut.

Antigen exposure in the late light period induces severe symptoms of food allergy in an OVA-allergic mouse model

The mammalian circadian clock controls many physiological processes that include immune responses and allergic reactions. Several studies have investigated the circadian regulation of intestinal permeability and tight junctions known to be affected by cytokines. However, the contribution of circadian clock to food allergy symptoms remains unclear. Therefore, we investigated the role of the circadian clock in determining the severity of food allergies. We prepared an ovalbumin food allergy mouse model, and orally administered ovalbumin either late in the light or late in the dark period under light-dark cycle. The light period group showed higher allergic diarrhea and weight loss than the dark period group. The production of type 2 cytokines, IL-13 and IL-5, from the mesenteric lymph nodes and ovalbumin absorption was higher in the light period group than in the dark period group. Compared to the dark period group, the mRNA expression levels of the tight junction proteins were lower in the light period group. We have demonstrated that increased production of type 2 cytokines and intestinal permeability in the light period induced severe food allergy symptoms. Our results suggest that the time of food antigen intake might affect the determination of the severity of food allergy symptoms.

Bioactive Egg Components and Inflammation

Inflammation is a normal acute response of the immune system to pathogens and tissue injury. However, chronic inflammation is known to play a significant role in the pathophysiology of numerous chronic diseases, such as cardiovascular disease, type 2 diabetes mellitus, and cancer. Thus, the impact of dietary factors on inflammation may provide key insight into mitigating chronic disease risk. Eggs are recognized as a functional food that contain a variety of bioactive compounds that can influence pro- and anti-inflammatory pathways. Interestingly, the effects of egg consumption on inflammation varies across different populations, including those that are classified as healthy, overweight, metabolic syndrome, and type 2 diabetic. The following review will discuss the pro- and anti-inflammatory properties of egg components, with a focus on egg phospholipids, cholesterol, the carotenoids lutein and zeaxanthin, and bioactive proteins. The effects of egg consumption of inflammation across human populations will additionally be presented. Together, these findings have implications for population-specific dietary recommendations and chronic disease risk.