Effects of Supplementary Seleno-L-methionine on Atopic Dermatitis-Like Skin Lesions in Mice

Dimethylglycine, a methionine metabolite, participates in the suppressive effect of methionine on 1-fluoro-2,4-dinitrobenzene-induced dermatitis

Allergic contact dermatitis (ACD) is a common skin disorder caused by contact with allergens. The optimal treatment for ACD is to avoid contact with allergens. However, in some cases, avoiding exposure is not possible when the allergens are unknown. Therefore, establishing treatment methods other than allergen avoidance is important. We previously reported that the continuous administration of methionine, an essential amino acid, in a mouse model of atopic dermatitis alleviated its symptoms. In the present study, we investigated the effect of methionine on a mouse model of ACD caused by 1-fluoro-2,4-dinitrobenzene (DNFB). Differences in the effect of methionine were observed in DNFB-induced ACD model mice based on the mouse strain used. This difference was attributed to the suppression of hepatic dimethylglycine (DMG) production, which is associated with the suppression of hepatic betaine-homocysteine methyltransferase (Bhmt) expression by ACD. Although we did not reveal the mechanism underlying DMG suppression, our study suggests the presence of interactions between the liver and skin in dermatitis, such as the regulation of hepatic metabolic enzyme expression in dermatitis and the alleviation of dermatitis symptoms by the hepatic metabolism status of DMG.

Portulaca oleracea L. extracts alleviate 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is a common chronic allergic skin disease characterized clinically by severe skin lesions and pruritus. Portulaca oleracea L. (PO) is a resourceful plant with homologous properties in medicine and food. In this study, we used two different methods to extract PO, and compared the therapeutic effects of PO aqueous extract (POAE) and PO ultrasound-assisted ethanol extract (POEE) on 2,4-dinitrochlorobenzene (DNCB)-induced AD mice. The results showed that in POAE and POEE, the extraction rates of polysaccharides were 16.95% and 9.85%, while the extraction rates of total flavonoids were 3.15% and 3.25%, respectively. Compared with AD mice, clinical symptoms such as erythema, edema, dryness and ulceration in the back and left ear were alleviated, and pruritus behavior was reduced after POAE and POEE treatments. The thickness of the skin epidermis was thinned, the density of skin nerve fibers labeled with protein gene product 9.5 (PGP9.5) was decreased, and mast cell infiltration was reduced. There was a decrease in blood lymphocytes, eosinophils and basophils, a significant decrease in spleen index and a noticeable decrease in serum immunoglobulin E (Ig E). POEE significantly reduced the concentration of the skin pruritic factor interleukin (Il)-31. POAE and POEE reduced the concentration of skin histamine (His), down-regulated mRNA expression levels of interferon-γ (Ifnγ), tumor necrosis factor-α (Tnf-α), thymic stromal lymphopoietin (Tslp) and Il-4, with an increase of Filaggrin (Flg) and Loricrin (Lor) in skin lesions. These results suggested that POAE and POEE may inhibit atopic response and alleviate the clinical symptoms of AD by inhibiting the expression of immune cells, inflammatory mediators and cytokines. PO may be a potential effective drug for AD-like diseases.

Role of selenium in IgE mediated soybean allergy development

Food allergy is a pathological immune reaction triggered by normal innocuous dietary proteins. Soybean is widely used in many food products and has long been recognized as a source of high-quality proteins. However, soybean is listed as one of the 8 most significant food allergens. The prevalence of soybean allergy is increasing worldwide and impacts the quality of life of patients. Currently, the only strategy to manage food allergy relies on strict avoidance of the offending food. Nutritional supplementation is a new prevention strategy which is currently under evaluation. Selenium (Se), as one of the essential micronutrients for humans and animals, carries out biological effects through its incorporation into selenoproteins. The use of interventions with micronutrients, like Se, might be an interesting new approach. In this review we describe the involvement of Se in a variety of processes, including maintaining immune homeostasis, preventing free radical damage, and modulating the gut microbiome, all of which may contribute to in both the prevention and treatment of food allergy. Se interventions could be an interesting new approach for future treatment strategies to manage soybean allergy, and food allergy in general, and could help to improve the quality of life for food allergic patients.

Selenium Modulates the Allergic Response to Whey Protein in a Mouse Model for Cow's Milk Allergy

Cow's milk allergy is a common food allergy in infants, and is associated with an increased risk of developing other allergic diseases. Dietary selenium (Se), one of the essential micronutrients for humans and animals, is an important bioelement which can influence both innate and adaptive immune responses. However, the effects of Se on food allergy are still largely unknown. In the current study it was investigated whether dietary Se supplementation can inhibit whey-induced food allergy in an animal research model. Three-week-old female C3H/HeOuJ mice were intragastrically sensitized with whey protein and cholera toxin and randomly assigned to receive a control, low, medium or high Se diet. Acute allergic symptoms, allergen specific immunoglobulin (Ig) E levels and mast cell degranulation were determined upon whey challenge. Body temperature was significantly higher in mice that received the medium Se diet 60 min after the oral challenge with whey compared to the positive control group, which is indicative of impaired anaphylaxis. This was accompanied by reductions in antigen-specific immunoglobulins and reduced levels of mouse mast cell protease-1 (mMCP-1). This study demonstrates that oral Se supplementation may modulate allergic responses to whey by decreasing specific antibody responses and mMCP-1 release.

Oral λ-carrageenan intake alleviates skin symptoms in a hapten induced atopic dermatitis-like model

Lambda carrageenan is a widely used food additive. It has been shown that its oral intake induces suppression of T cell proliferation and antibody-mediated and cell-mediated immune response in experimental animals. In this study, we estimated the effect of oral ingestion of 0.001% λ-carrageenan on trinitrochlorobenzen-induced atopic dermatitis model mouse. Oral carrageenan ingestion alleviated ear swelling of hapten challenged mice and significantly suppressed mast cell hyperplasia in the topical skin. Serological analysis revealed that the treatment suppressed total IgE and antigen-specific IgG, and also suppressed both allergy driving cytokine interleukin-4 and counter-acting cytokine interferon-γ levels. It is suggested that the oral ingestion of λ-carrageenan may suppress the immunological response to the allergen and might be useful to treat atopic dermatitis.

Lithraea caustic (Litre) Extract Promotes an Antitumor Response Against B16 Melanoma

Melanoma immunotherapy, specifically the autotransplant of dendritic cells charged with tumors antigens, has shown promising results in clinical trials. The positive clinical effects of this therapy have been associated to increased Th17 response and delayed-type hypersensitivity (DTH) against to tumor antigens. Some synthetic compounds, such as diphenylcyclopropenone (DPCP), are capable of triggering a DTH response in cutaneous malignancies and also to induce clinically relevant effects against melanoma. In this work, we evaluated Litre extract (LExT), a standardized extract of a Chilean stinging plant, Lithraea caustic (Litre). As Litre plant is known to induce DTH, we used a murine B16 melanoma model to compare the topical and intratumor efficacy of LExT with synthetic DTH inducers (DPCP and 2,4-dinitrochlorobenzene [DNCB]). LExt contained mainly long chain catechols and sesquiterpenes. The intratumor injection of LExT induced a significant delay in tumor growth, similarly topical treatment of an established tumor with 0.1% LExT ointment induced a growth delay and even tumor regression in 15% of treated animals. No significant changes were observed on the T-cell populations associated to LExT treatment, and neither DNCB nor DPCP were capable to induce none of the LExT-induced antitumoral effects. Interestingly, our results indicate that LExT induces an antitumor response against melanoma in a mouse model and could bring a new –and affordable- treatment for melanoma in humans.

Seleno-L-Methionine Suppresses Immunoglobulin E-Mediated Allergic Response in RBL-2H3 Cells

The effect of seleno-L-methionine (SeMet) on immunoglobulin (Ig) E-mediated allergic responses were investigated using rat basophilic leukemia RBL-2H3 cells. Cells were first treated with or without SeMet, sensitized with anti-dinitrophenyl IgE and stimulated with the antigen dinitrophenyl-human serum albumin, before the measurement of degranulation, calcium mobilization, mRNA expression and protein secretion of interleukin (IL)-4 and tumor necrosis factor (TNF)-α, and phosphorylation of spleen tyrosine kinase (Syk), Akt, and mitogen-activated protein kinases (MAPKs). The antigen-induced β-hexosaminidase release, a degranulation marker, was significantly inhibited by SeMet treatment. SeMet also significantly suppressed antigen-induced calcium mobilization. Antigen-induced increases in the mRNA expression and protein secretion of IL-4 and TNF-α were both significantly attenuated by SeMet treatment. In addition, SeMet significantly suppressed antigen-induced phosphorylation of Syk, Akt, and MAPKs. These results demonstrate that SeMet suppresses antigen-induced degranulation, and mRNA expression and protein secretion of IL-4 and TNF-α, and inhibits antigen-induced mobilization of calcium and activation of Syk, Akt, and MAPKs. Our study provides valuable information that may be useful in the prevention and treatment of allergic diseases.