Olfactory cleft proteome does not reflect olfactory performance in patients with idiopathic and postinfectious olfactory disorder: A pilot study

Abstract

Technical advances including liquid chromatography–tandem mass spectrometry and its data analysis enable detailed proteomic analysis of the nasal mucus. Alterations of the nasal mucus proteome may provoke substantial changes of the nasal physiology and have already been associated with rhinologic diseases such as allergic rhinitis. This study was conducted as a pilot study to map the olfactory cleft proteome using current techniques for proteomic analysis. Furthermore, we aimed to investigate proteomic changes as potential biomarkers in patients suffering from idiopathic and postinfectious olfactory disorders compared to healthy controls. Seven patients with idiopathic hyposmia and anosmia, seven patients with postinfectious hyposmia and anosmia and seven healthy controls were included in this study. In total, 1117 different proteins were detected in at least five patients in at least one group. Results of this study did not reveal significant differences regarding the proteomic composition of the olfactory cleft mucus between patients versus healthy controls. Among proteins involved in olfactory perception the G protein family was detected but also found unchanged between groups. Investigation of protein composition by liquid chromatography–tandem mass spectrometry enabled us to perform an in–depth analysis of the olfactory cleft mucus proteome regarding the diversity of different proteins in individual patients. However untargeted proteomics of the olfactory cleft mucus may not be an applicable approach to develop biomarkers for olfactory disorders. Targeted analyses of distinct proteins known to be involved in olfactory perception but not detected by our approach, e.g. odorant binding proteins, may provide more information regarding pathophysiology of olfactory diseases.

The odorant metabolizing enzyme UGT2A1: Immunolocalization and impact of the modulation of its activity on the olfactory response

“…It is unlikely that UGT could be present in the mucus because its activity has been shown to be dependent to the surrounding phospholipids in the membrane [30][31][32]. Accordingly, proteomic studies did not evidence UGT protein in the mucus in rat or human [4,[33][34][35], while, as confirmed by our results, UGT2A1 has been detected in olfactory cilia proteome [36,37]. One should note that cross-reactivity of the antibodies with the UGT2A2 variant cannot be ruled out.…”

Olfactory cleft mucus proteome in chronic rhinosinusitis: a case‐control pilot study

“…Comparison of results to other published studies showed that 69 of 84 proteins (82%) detected by Débat et al 12 were identified in the present study. Similarly, 1075 of 1117 proteins (96%) detected by Wolf et al 13 were detected in the present study. The overall number of mucus proteins in the current study (N = 2514) was similar to that reported in the OC mucus of non-CRS aging subjects (N = 2586).…”

“…12 Using current shotgun techniques, 2 additional studies have been reported within the last 2 years, both identifying well over 1000 unique proteins. 13,14 However, neither of these studies included patients with CRS. It thus remains unknown whether the proteomic profile of patients with CRS differs from controls without CRS, particularly with regard to OBPs or metabolizing enzymes, nor is it known whether changes are associated with olfactory function.…”

“…The initial study published in 2007 was able to identify 83 unique proteins in healthy controls 12 . Using current shotgun techniques, 2 additional studies have been reported within the last 2 years, both identifying well over 1000 unique proteins 13,14 . However, neither of these studies included patients with CRS.…”

European position paper on diagnostic tools in rhinology

“…This technique is well tolerated and has the advantage of minimal stimulation and/or trauma to the mucosa. Moreover, certain areas of the nose can be directly suctioned under endoscopic control, for example the middle meatus or the olfactory cleft (235) .…”