Olfactory cleft mucus proteins associated with olfactory dysfunction in a cohort without chronic rhinosinusitis

• Published in: International forum of allergy & rhinology Vol. 9; no. 10; pp. 1151 - 1158
• Main Authors: Yoo, Frederick, Soler, Zachary M., Mulligan, Jennifer K., Storck, Kristina A., Lamira, Jensine M., Pasquini, Whitney N., Hill, Jonathan B., Noonan, Tegan E., Washington, Brandon J., Schlosser, Rodney J.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.10.2019
• Subjects: Adult; Aged; anosmia; CCL20 protein; Chemokines; Chronic Disease; Cohort Studies; Cyclin-Dependent Kinase Inhibitor p16 - metabolism; Cytokines; Demography; Diagnosis, Differential; Enzyme inhibitors; Family medical history; Female; Fibroblast growth factor 2; Fibroblast Growth Factor 2 - metabolism; growth factor; Growth factors; Humans; hyposmia; INK4a protein; Leukocytes (granulocytic); Ligands; Localization; Macrophages; Male; Middle Aged; Monocyte chemoattractant protein 1; Mucus; Mucus - metabolism; Nasal Cavity - pathology; nasal mucosa; Nose; Odorant-binding protein; Olfaction; Olfaction disorders; Olfaction Disorders - diagnosis; Olfaction Disorders - metabolism; Olfactory discrimination; Olfactory discrimination learning; olfactory disorders; Olfactory Mucosa - metabolism; Olfactory Mucosa - pathology; olfactory test; Olfactory thresholds; p16 Protein; Population studies; Proteins; Receptors, Odorant - metabolism; Rhinitis; Rhinitis - diagnosis; Rhinitis - metabolism; Rhinosinusitis; Sinusitis; Sinusitis - diagnosis; Sinusitis - metabolism; Stem cell factor; Stem cells; growth factor; olfactory test; anosmia; nasal mucosa; olfaction; cytokines; olfactory disorders; hyposmia
• ISSN: 2042-6976; 2042-6984; 2042-6984
• DOI: 10.1002/alr.22391

Background Olfactory dysfunction (OD) is a common problem, affecting up to 20% of the general population. Previous studies identified olfactory cleft mucus proteins associated with OD in chronic rhinosinusitis (CRS) but not in a healthy population. In this study we aimed to identify olfactory cleft mucus proteins associated with olfaction in individuals without sinus disease. Methods Subjects free of sinus disease completed medical history questionnaires that collected data regarding demographics, comorbidities, and past exposures. Olfactory testing was performed using Sniffin’ Sticks, evaluating threshold, discrimination, and identification. Olfactory cleft mucus (OC) and, in select cases, inferior turbinate mucus (IT) were collected with Leukosorb paper and assays performed for 17 proteins, including growth factors, cytokines/chemokines, cell‐cycle regulators, and odorant‐binding protein (OBP). Results Fifty‐six subjects were enrolled in the study, with an average age of 47.8 (standard deviation [SD], 17.6) years, including 33 females (58.9%). The average threshold/discrimination/identification (TDI) score was 30.3 (SD, 6.4). In localization studies, OBP concentrations were significantly higher in OC than IT mucus (p = 0.006). Cyclin‐dependent kinase inhibitor 2A (CDKN2A/p16INK4a), basic fibroblast growth factor (bFGF), chemokine ligand 2 (CCL2/MCP‐1), granulocyte macrophage colony‐stimulating factor (GM‐CSF), and chemokine ligand 20 (CCL20/MIP‐3a) all inversely correlated with overall TDI (all rho ≥ ‐0.479, p ≤ 0.004). Stem cell factor (SCF) correlated positively with overall TDI (rho = 0.510, p = 0.002). Conclusion Placement of Leukosorb paper is relatively site‐specific for olfactory proteins and it is feasible to collect a variety of olfactory cleft proteins that correlate with olfactory function. Further study is required to determine mechanisms of OD in non‐CRS subjects.