Aims: 

Rhinosinusitis is a chronic inflammation of the paranasal sinuses which can be of non-polypous and polypous form. The latter subgroup is characterized by an infiltration of eosinophils leading to polyp formation. Mast cells, B lymphocytes and activated T cells accumulate as well. Only recently, transient receptor potential vanilloid receptor 1 (TRPV1) receptors of unclear function have been identified on non-neural cells such as various immune and inflammatory cells. Non-neuronal transient receptor potential ankyrin 1 (TRPA1) channel is expressed by epidermal, dermal, epithelial, mucosal but not immune cells. We aimed to detect the existence of TRPV1 and TRPA1 receptor proteins and non-neural expression of their mRNA in rhinosinusitis.

Methods: 

Polypous (n=33) and non-polypous rhinosinusitis samples (n=6) along with non-inflammed control specimens (n=4) were obtained during routine surgery. Immunohistochemistry was performed with polyclonal rabbit TRPV1 and TRPA1 antibodies on paraffin-embedded sections. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was carried out on a Roche Light Cycler instrument by TaqMan primers and probes.

Results: 

Our immunohistochemical evidence shows that TRPV1 and TRPA1 receptors are expressed in biopsy samples of rhinosinusitis. Strong specific TRPV1 immuno-positivity was observed in mast cells. Epithelial and glandular cells were stained by TRPA1 antibody. The local mRNA expression of these extraneural receptors was also proven. In non-polypous and in polypous rhinosinusitis without the comorbid conditions of asthma and allergic rhinitis, gene expression levels of TRPV1 increased while levels of TRPA1 remained unchanged compared to normal nasal mucosa. There was a slight increase in TRPV1 transcripts when patients with nasal polyposis and comorbid conditions were compared to polyp patients without them.

Conclusion: 

We suppose that extraneural TRPV1 but not TRPA1 receptors might participate in the pathomechanism of rhinosinusitis.