Influence of Neopterin on Ciliary Beat Frequency of Human Nasal Epithelial Cells in vitro

Acute infectious diseases of the respiratory tract are regularly associated with increased concentrations of neopterin in serum and/or urine. Most likely, the pteridine compound is not only a marker of an activated cellular immune system but may exert distinct biochemical functions in the process of infections as well. In response to viral contact, macrophages located in the nasal mucosa may represent a source for neopterin in the nasal cavity with potential hazardous effects on ciliary beat frequency (CBF), thus promoting chronic infectious processes. The aim of the present study was to investigate the effects of neopterin at different concentrations (10 nM, 100 nM, and 100 μM) on CBF in human nasal epithelial cells in vitro. Samples were taken from the inferior nasal turbinate and incubated with neopterin dissolved in either aqua destillata or in sodium chloride (0.9%) at the given amounts for 2, 5, 10, and 20 min. In a preliminary set of experiments, neopterin inhibited CBF following the 5 and 10 min. incubation protocol, respectively. However, analyses of pooled data from 28 experiments using sodium chloride (0.9%) as solvent could not confirm these findings: in no setting a significant reduction of CBF was detected at the end of the 20 min. experimental procedure. Therefore, we conclude that neopterin most likely does not affect the mucociliary clearance defense mechanisms in the course of infections of the nasal respiratory tract.