5-HT₇ receptors are over-expressed in patients with nasal polyps

Nasal polyposis (NP) is an inflammatory disease of the paranasal sinuses and nasal cavity. The primary purpose of our study is to determine the expression of 5-HT₇ receptors both in nasal polyps and in healthy tissue in the nasal cavity. The subsequent aim is to compare the expression of 5-HT₇ receptors in patients with NP and in inferior turbinate tissue (control). The study included 60 participants (40 with NP and 20 controls) aged 35 to 62 years. Nasal polyp samples were collected from all patients and relative 5-HT₇ receptor expression analyses were performed. Reverse transcription polymerase chain reaction analysis of nasal polyps and control tissue identified 5-HT₇ receptor expression in the nasal cavities of controls. This expression was approximately 67 times higher in nasal polyp tissue than in healthy tissue. Our study identifies the expression of 5-HT₇ receptors in the nasal cavity for the first time and the first demonstration of increased 5-HT₇ receptor expression in tissue from nasal polyps, which occur in the paranasal sinuses and nasal cavity.