Investigation of trigeminal detection thresholds at the human nasal mucosa in healthy subjects and patients with chronic rhinosinusitis before and after sinus surgery and investigation of Solitary Chemosensory Cells (SCCs) in the human nasal mucosa

• Applicant: Dr. Mandy Scheibe
• Subject Area: Otolaryngology, Phoniatrics and Audiology
• Term: Funded in 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 198453995

Aim: The following two studies focus on the sensitivity in the human nasal mucosa which is mediate by the trigeminal nerve. The first study is designed to determine trigeminal sensitivity in patient with chronic rhinosinusitis before and after sinus surgery in comparison to healthy controls. Background of this study is the question whether trigeminal sensitivity is reduced in patient and whether it is due to the inflammation of the nasal mucosa. The second study aims to investigate the presence of so-called Solitary Cemosensory Cells (SCCs) in the human nasal mucosa which have already been shown to be functional in animals. These SCCs are innervated by trigeminal afferents and provide responses to a large variety of chemosensory stimuli. Preliminary data also indicate that similar structures probably are present in humans. Material and methods: Electrical stimuli will be applied in an ascending method till the detection threshold at the anterior nasal septum and the nasal middle turbinate in 30 healthy subjects and 30 patients prior sinus surgery. In case of the patients the measurement will be performed prior sinus surgery, and three month after surgery. Furthermore biopsies of human nasal mucosa will be obtained from 20 patients during nasal surgery. These biopsies will be processed for immunohistochemistry and investigated concerning SCCs as well as synaptic contacts with trigeminal afferent nerve fibers.Hypotheses: 1. The chronic inflammation of the nasal mucosa leads to a reduced trigeminal sensitivity and thus to a reduced sensitivity for nasal airflow. This contributes to the sensation of a congested nose. The sinus surgery improves the nasal and sinus ventilation and may stop the chronic inflammation. Thus after sinus surgery the trigeminal sensitivity should be improved. 2. It is expected that SCCs are present in the human nasal epithelium and that they are innervated by trigeminal nerve fibers.

• DFG Programme: Research Fellowships
• International Connection: Australia
• Host: Professor Alan Mackay-Sim