Respiratory epithelium is a crucial defense against inhaled pathogens. Health care practitioners suggest Vitamin D3 (VD) modulator for airway inflammation; however, its effect on innate airway defenses, the physical barrier, mucociliary apparatus, and cytokine release remains unclear.

Researchers did this study to investigate VD application outcomes before the challenge in an in vitro model of the human sinonasal epithelium, through assessment of epithelial TER,  CBF, and IL-6 release. They also aimed to determine whether topical VD is beneficial to patients with inflammatory sinonasal pathology.

Well-differentiated cultures from each patient were pretreated for 24 hours with four different VD doses. Toxicity was quantified at 24 hours in unchallenged ALI by LDH assay. Innate responses were assessed by measuring TER and CBF before and up to 24 hours after house dust mite Dermatophagoides pteronyssinus challenge. The present study assessed Fifteen patients representing 120 ALI.

The study concluded that the topical VD supplementation in eCRS patients might be beneficial for innate epithelial defenses. VD is noncytotoxic and does not adversely affect the physical barrier, mucociliary apparatus, or IL-6 release.