Intestinal absorption of the wheat allergen gliadin in rats

A Quantity-Dependent Nonlinear Model of Sodium Cromoglycate Suppression on Beta-Conglycinin Transport

Understanding the transport mechanism is crucial for developing inhibitors that block allergen absorption and transport and prevent allergic reactions. However, the process of how beta-conglycinin, the primary allergen in soybeans, crosses the intestinal mucosal barrier remains unclear. The present study indicated that the transport of beta-conglycinin hydrolysates by IPEC-J2 monolayers occurred in a time- and quantity-dependent manner. The beta-conglycinin hydrolysates were absorbed into the cytoplasm of IPEC-J2 monolayers, while none were detected in the intercellular spaces. Furthermore, inhibitors such as methyl-beta-cyclodextrin (MβCD) and chlorpromazine (CPZ) significantly suppressed the absorption and transport of beta-conglycinin hydrolysates. Of particular interest, sodium cromoglycate (SCG) exhibited a quantity-dependent nonlinear suppression model on the absorption and transport of beta-conglycinin hydrolysates. In conclusion, beta-conglycinin crossed the IPEC-J2 monolayers through a transcellular pathway, involving both clathrin-mediated and caveolae-dependent endocytosis mechanisms. SCG suppressed the absorption and transport of beta-conglycinin hydrolysates by the IPEC-J2 monolayers by a quantity-dependent nonlinear model via clathrin-mediated and caveolae-dependent endocytosis. These findings provide promising targets for both the prevention and treatment of soybean allergies.

Transport of glycinin, the major soybean allergen, across intestinal epithelial IPEC-J2 cell monolayers

Soybean allergen entering the body is the initial step to trigger intestinal allergic response. However, it remains unclear how glycinin, the major soybean allergen, is transported through the intestinal mucosal barrier. The objective of this study was to elucidate the pathway and mechanism of glycinin hydrolysate transport through the intestinal epithelial barrier using IPEC-J2 cell model. Purified glycinin was digested by in vitro static digestion model. The pathway and mechanism of glycinin hydrolysates transport through intestinal epithelial cells were investigated by cellular transcytosis assay, cellular uptake assay, immunoelectron microscopy and endocytosis inhibition assay. The glycinin hydrolysates were transported across IPEC-J2 cell monolayers in a time/dose-dependent manner following the Michaelis equation. Immunoelectron microscopy showed a number of glycinin hydrolysates appeared in the cytoplasm, but no glycinin hydrolysates were observed in the intercellular space of IPEC-J2 cells. The inhibitors, colchicine, chlorpromazine and methyl-β-cyclodextrin, significantly inhibited the cellular uptake of glycinin hydrolysates. The glycinin hydrolysates crossed IPEC-J2 cell monolayers through the transcellular pathway. Both clathrin- and caveolae-dependent endocytosis were involved in the epithelial uptake of the hydrolysates. These findings provided potential targets for the prevention and treatment of soybean allergy.

Study on the transport and internalisation mechanism of dietary supplement nattokinase in the small intestine using animal and Caco-2 cell monolayer models

Maintaining proper blood flow is critical to promoting good health. Nattokinase is a serine protease from Bacillus subtilis that has significant in vitro thrombolytic activity, but its mechanism as a dietary supplement to prevent thrombosis through intestinal absorption and transport is still unclear.The purpose of this study is to study the transport and internalisation mechanism of NK in the small intestine using animal models and Caco-2 cell monolayer models.This study first evaluated the preventive effect of supplementing low dose (4000 FU (Fibrin Unit)/kg, n = 6), medium dose (8000 FU/kg, n = 6), and high dose (12000 FU/kg, n = 6) of nattokinase on carrageenan induced thrombosis in mice. Subsequently, we used the rat gut sac model, ligated intestinal loop model, and Caco-2 cell uptake model to study the intestinal transport mechanism of NK.Results indicate that NK is a moderately absorbed biomolecule whose transport through enterocytes is energy- and time-dependent. Chlorpromazine, nystatin and EIPA all inhibited the endocytosis of NK to varying degrees, indicating that the endocytosis of NK in Caco-2 cells involves macropinocytosis, clathrin-mediated and caveolae-mediated pathway. These findings offer a theoretical basis for investigating the mechanism of oral NK supplementation in greater depth.

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.

Colon and gut microbiota greatly affect the absorption and utilization of astaxanthin derived from Haematococcus pluvialis

Astaxanthin has been widely favored as a health food supplement by individuals but its absorption in the body seems not to be satisfactory. In addition, the peak time of astaxanthin derived from Haematococcus pluvialis in the plasma was much longer than other carotenoids found in our previous research. Thus, it is necessary to explore the process that affects the absorption of astaxanthin in order to potentially find a novel approach to improve the absorption in the future. In this study, we confirmed that the colon has an ability to absorb astaxanthin and conducted acute feeding experiments with the treatment of antibiotics in C57BL/6J mice and chronic feeding experiments in germ-free (GF) mice to detect the relationship between the gut microbiota and the absorption of astaxanthin. Our study showed that the decrease of gut microbiota led to a less oral absorbability, which might be related to the decreased expression of SR-BI in the small intestine and the reduction of free form and Z-astaxanthin converted by the gut microbiota found in the vitro culture. The experiments of anaerobic culture also implied that Lactobacillus might play an important role in the absorption of astaxanthin.

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.