[Primary nasal epithelial cells and fibroblasts have inflammation-inducing functions]

The appearance of neutrophils in rhinitis and sinusitis led to the working hypothesis that neutrophil-specific attractants commonly called chemokines are generated by stimulation with proinflammatory cytokines and bacteria. The receptor mechanism of chemokine synthesis by bacterial products is under discussion and still has to be elucidated.

The primary nasal cultures of epithelial cells and fibroblasts ( n=4) were incubated with TNF-alpha (tumor necrosis factor) for 24 and 72 h. Bacterial stimulation of the cell cultures was performed by adding supernatants from the mucoid phenotype of Pseudomonas aeruginosa (PA01) in dilution 1:5 for 24 and 72 h. Supernatants were collected and the concentration of the chemokines interleukin-8 (IL-8), GRO-alpha (growth-related oncogene-alpha), and ENA-78 (epithelial neutrophil-activating peptide) were determined by ELISA technique. Our results revealed that the protein concentration of the chemokines GRO-alpha and IL-8 was upregulated by TNF-alpha as well as by bacterial supernatants in epithelial cells.

We conclude that GRO-alpha and IL-8 were inducible by bacterial supernatants in nasal epithelial cells and fibroblasts.