Dietary intervention with galactooligosaccharides is as effective or may be more effective as the treatment with the corticosteroid, budesonide, in a house dust mite-induced model of allergic asthma

Allergic asthma is associated with hypersensitivity to house dust mite (HDM). Characterized by a Th2 immune response, asthma leads to mucus hypersecretion, eosinophilic inflammation in the airways and airway hyperresponsiveness (AHR). Recently, there has been an increased interest in using specific dietary oligosaccharides as a novel strategy to prevent the development or reduce symptoms in asthma. We investigated the effect of dietary galacto-oligosaccharides (GOS) compared to an intra-airway treatment with the glucocorticosteroid, budesonide, on the development of several features of HDM-induced allergic asthma. BALB/c mice were intranasally sensitized with 1 lg HDM on day 0. Mice were daily challenged intranasally with PBS (control) or 10 lg HDM on days 7-11. From day -14 till 14 mice were fed a control diet or a diet containing 1% GOS. As reference, mice were instilled oropharyngeally with budesonide (500 μg/kg) on day 7, 9, 11, and 13. On day 14 airway resistance was measured to increasing doses of methacholine in the airways. Bronchoalveolar lavage (BAL) fluid and lungs were collected for further research. Dietary intervention with 1% GOS, but not budesonide, prevented the development of HDM-induced AHR. HDM allergy resulted in a significant increase in the number of leukocytes in the BAL fluid. Dietary intervention with 1% GOS or treatment with budesonide resulted in a significant decrease in total number of leukocytes in the BAL fluid, represented by a decrease of macrophage and eosinophils. HDM allergy resulted in significantly enhanced concentrations of IL-6, IL-13 and IL-33 in lung homogenates. Dietary intervention with 1% GOS significantly decreased the HDM-induced IL-13 concentration in lung homogenates. The HDM-induced increases in pulmonary IL-6 and IL- 13 were significantly decreased after budesonide treatment. The HDMinduced increase in IL-33 levels in the lungs tended to decrease with 1% GOS and tended to increase with budesonide. 1% GOS prevented the development of AHR, the influx of inflammatory cells into the lungs and the pulmonary Th2 cytokine response in HDM allergic mice. We conclude that a dietary intervention with 1% GOS is as effective or may be more effective as the treatment with the glucocorticosteriod budesonide in a HDM-induced model of allergic asthma.