RESUMEN
Background: Dietary non-digestible galacto-oligosaccharides (GOS) suppress allergic responses in mice sensitized and challenged with house dust mite (HDM). Budesonide is the standard therapy for allergic asthma in humans but is not always completely effective. Aim: To compare the efficacy of budesonide or different doses of GOS alone or with a combination therapy of budesonide and GOS on HDM-allergic responses in mice. Methods:BALB/c mice were sensitized and challenged with HDM, while fed a control diet or a diet supplemented with 1 or 2.5 w/w% GOS, and either or not oropharyngeally instilled with budesonide. Systemic and local inflammatory markers, such as mucosal mast cell protease-1 (mMCP-1) in serum, pulmonary CCL17, CCL22, and IL-33 concentrations and inflammatory cell influx in the bronchoalveolar lavage fluid (BALF) were determined. Results: Budesonide or GOS alone suppressed the number of eosinophils in the BALF of HDM allergic mice whereas budesonide either or not combined with GOS lowered both eosinophil and lymphocyte numbers in the BALF of HDM-allergic mice. Both 1 w/w% and 2.5 w/w% GOS and/or budesonide suppressed serum mMCP-1 concentrations. However, budesonide nor GOS alone was capable of reducing Th2 driving chemokines CCL17, CCL22 and IL-33 protein levels in supernatants of lung homogenates of HDM allergic mice, whereas the combination therapy did. Moreover, IL-13 concentrations were only significantly suppressed in mice treated with budesonide while fed GOS. A similar tendency was observed for the frequency of GATA3+CD4+ Th2 and CD4+RORγt+ Th17 cells in the lungs of the allergic mice. Conclusion: Dietary intervention using GOS may be a novel way to further improve the efficacy of anti-inflammatory drug therapy in allergic asthma by lowering Th2 driving mediators and mast cell degranulation.
Asunto(s)
Antiinflamatorios/uso terapéutico , Asma/terapia , Budesonida/uso terapéutico , Hipersensibilidad/terapia , Pulmón/patología , Mastocitos/inmunología , Oligosacáridos/administración & dosificación , Células Th2/inmunología , Animales , Antígenos Dermatofagoides/inmunología , Degranulación de la Célula , Terapia Combinada , Citocinas/metabolismo , Suplementos Dietéticos , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Endogámicos BALB C , Pyroglyphidae/inmunología , Balance Th1 - Th2RESUMEN
BACKGROUND: The integrity of the epithelial layer in the gastrointestinal tract protects organisms from exposure to luminal antigens, which are considered the primary cause of chronic intestinal inflammation and allergic responses. The common wheat-associated fungal toxin deoxynivalenol acts as a specific disruptor of the intestinal tight junction network and hence might contribute to the pathogenesis of inflammatory bowel diseases. OBJECTIVE: The aim of the current study was to assess whether defined galacto-oligosaccharides (GOSs) can prevent deoxynivalenol-induced epithelial dysfunction. METHODS: Human epithelial intestinal Caco-2 cells, pretreated with different concentrations of GOSs (0.5%, 1%, and 2%) for 24 h, were stimulated with 4.2-µM deoxynivalenol (24 h), and 6/7-wk-old male B6C3F1 mice were fed a diet supplemented with 1% GOSs for 2 wk before being orally exposed to deoxynivalenol (25 mg/kg body weight, 6 h). Barrier integrity was determined by measuring transepithelial electrical resistance (TEER) and intestinal permeability to marker molecules. A calcium switch assay was conducted to study the assembly of epithelial tight junction proteins. Alterations in tight junction and cytokine expression were assessed by quantitative reverse transcriptase-polymerase chain reaction, Western blot analysis, or ELISA, and their localization was visualized by immunofluorescence microscopy. Sections of the proximal and distal small intestine were stained with hematoxylin/eosin for histomorphometric analysis. RESULTS: The in vitro data showed that medium supplemented with 2% GOSs improved tight junction assembly reaching an acceleration of 85% after 6 h (P < 0.05). In turn, GOSs prevented the deoxynivalenol-induced loss of epithelial barrier function as measured by TEER (114% of control), and paracellular flux of Lucifer yellow (82.7% of prechallenge values, P < 0.05). Moreover, GOSs stabilized the expression and cellular distribution of claudin3 and suppressed by >50% the deoxynivalenol-induced synthesis and release of interleukin-8 [IL8/chemokine CXC motif ligand (CXCL8)] (P < 0.05). In mice, GOSs prevented the deoxynivalenol-induced mRNA overexpression of claudin3 (P = 0.022) and CXCL8 homolog keratinocyte hemoattractant (Kc) (Cxcl1) (P = 0.06) as well as the deoxynivalenol-induced morphologic defects. CONCLUSIONS: The results demonstrate that GOSs stimulate the tight junction assembly and in turn mitigate the deleterious effects of deoxynivalenol on the intestinal barrier of Caco-2 cells and on villus architecture of B6C3F1 mice.