Soluble corn fiber reduces ovalbumin-induced sinonasal inflammation via the gut microbiota-airway axis

Asthma is a chronic airway inflammatory disease that affects approximately 300 million people worldwide, causing a substantial healthcare burden. Although there is a large degree of heterogeneity in the inflammatory response of asthmatics, a subset of patients are characterized by type-2 inflammation, which is in part mediated by T2 cells in both the upper and lower airways. Asthma prevalence is increased in low-socioeconomic-status populations, where disparities in health behavior exist, including a shift toward a western diet characterized by low dietary fiber. Gut microbes metabolize fiber into short chain fatty acids that can reduce type-2 inflammation in peripheral organs, such as the airways. We hypothesized that soluble fiber can reduce ovalbumin (OVA)-induced upper airway inflammation in the context of the unified airway hypothesis, in mice maintained on ingredient-matched western (WD) and control diets (CD) through production of short chain fatty acids. Our results show that soluble fiber reduces and gene expression (p<0.05, Mann Whitney) in the sinonasal cavity of CD-fed mice, but this effect was lost in WD-fed mice. This loss of protection in WD-fed mice parallels compositional changes of the cecal and fecal microbiota. Mice fed a soluble fiber supplement while being maintained on a WD had altered microbial communities characterized by lower abundance of fiber fermentering bacteria. This work can be used to develop effective microbiome-based therapeutics as a low-cost method to reduce asthma morbidity.