Abstract
Recent studies have highlighted the role of impaired barrier function and aberrant epithelial cell responses in the pathogenesis of allergy and asthma. Epidemiological studies showed that children growing up on farms have a lower incidence of childhood asthma, which was attributed to high microbial exposure. Interestingly, microbial exposure was found to enhance the epithelial barrier function in the gut and to maintain homeostasis. Therefore, we hypothesized that a microbe-rich environment present in farm dust may have a similar barrier-enhancing effect in the airway epithelium.
In this study, the effect of farm dust extracts (FDE) on barrier function and repair was investigated in primary bronchial epithelial cells (PBECs). Epithelial barrier function was analysed by assessing resistance (electric cell substrate impedance sensing and Trans Epithelial Electric Resistance (TEER)) and permeability (FITC-Dextran flux). FDE exposure induced a dose-dependent two-fold increase in barrier resistance and up to 70% reduction in permeability. An approximately 1.5-fold increased mRNA expression of occludin-1 and ZO-1 was observed after 24 hours of FDE exposure. Exposure of fully differentiated PBEC cultures to cigarette smoke (CS) resulted in a temporary decrease in TEER, and FDE accelerated the subsequent recovery of epithelial barrier resistance. These data altogether suggest that FDE exposure may strengthen the epithelial barrier function and thereby possibly reduce the risk of development of asthma and allergies.
- Copyright ©ERS 2015