Potential prevention of asthma development by means of human milk oligosaccharides.

Abstract

With an incidence of 11 million new cases per year and a prevalence of 374 million cases, asthma is a prominent allergic disease. In asthmatic patients, the immune system acts hyper sensitive upon encounter with an allergen such as house dust mite (HDM). As a result, patients with asthma suffer from coughing, sneezing and chest tightness, resulting in a depleted life quality. This substantiates the high need for research to the fundamentals of asthma and potential preventative methods. Over the past decades, a correlation has been shown between breast feeding and the development of asthma. The human milk components human milk oligosaccharides (HMOS) have been suggested as potential preventative players against asthma. However, the underlying mechanisms of HMOS on asthma prevention are yet to be elucidated. Therefore, the aim of this study was to explore the potential preventative effect of systemic HMO1 and HMO2 on airway epithelium upon HDM exposure. First, an HDM titration was performed on Calu-3 cells. Subsequently, Calu-3 cells were incubated with HMO1 or HMO2, and exposed to HDM. Also, an in vivo experiment was performed with BALB/c mice fed a diet containing HMO1 or HMO2 and sensitised to HDM. It was insignificantly determined that ALI conditions exposed to HDM after 24 hours exerted representative circumstances in vitro. This suggests that ALI can be applied as a model to mimic the lung in vitro and that HDM exerts its effect on the lungs within 24 hours. Additionally, the conditions incubated with HMO1 and HMO2 potentially showed a protective trend over the lung epithelial cells that were exposed to HDM reflected by the TEER in vitro. These results advocate for a potential protective mechanism of HMO1 and HMO2 on the lung epithelial cells when they are exposed to HDM, though repetition of the experiment is needed. In vivo mice exposed to HDM significantly depicted high fractions of activated DCs compared to Sham mice, but lower fractions of CD86+ expressing DCs, without a significant effect of HMO1 or HMO2. This suggests that DCs are activated by HDM and subsequently migrate to the lymph nodes in order to activate naive T cells.