Septum submucosal glands exhibit aberrant morphology and reduced mucin production in chronic rhinosinusitis

Abstract

Background: Chronic rhinosinusitis (CRS) is characterized by significant accumulation and thickening of mucus in the sinonasal cavities. One contributor of aberrant mucus production and impaired mucociliary clearance (MCC) is altered function of the sinonasal submucosal glands (SMGs), yet contributions of SMGs to upper airway disease initiation and progression remain unknown. The objective of this study was to characterize the morphology and secretory cell identities of the nasal septum SMGs in both healthy and CRS adults.Methods: Biopsies from adult participants with CRS without nasal polyps (CRSsNP, n = 4), CRS with nasal polyps (CRSwNP, n = 8), and non-CRS controls (n = 14) were collected from the posterior septum. Glandular morphology and mucus markers were investigated using histological techniques and highresolution confocal microscopy. Results: Analysis revealed a significant decrease in gland density in the posterior septum of CRSsNP (28% ± 6.15%) and CRSwNP (23% ± 3.09%) compared to control participants (53% ± 1.59%, p < 0.0001). Further analysis of the CRS SMG secretory function revealed an overall decrease in Mucin 5B+ gland mucus being produced. Dilated and cystic ductal structures filled with inspissated mucus were also common to CRS glands. Conclusion:Here, we describe a significant alteration in SMG structure and function in the adult CRS posterior septum suggesting reduced gland contribution to MCC. The SMGs of both the nose and sinuses may represent targets for future therapeutic approaches.

Year in review: 2021 IFAR article summary

“…Arnold et al 15 determined that antibiotic use increased over time and was higher for acute sinusitis compared to acute pharyngitis or CRS. Nnabue et al 16 used histological techniques and high-resolution confocal microscopy to demonstrate a significant decrease in gland density in the posterior septum of patients with CRS, and decreased secretory function, suggesting a possible component of the differences in mucociliary clearance in patients with CRS compared to controls.…”

Role of fern test in rhinosinusitis

“…We read with great interest the study by Nnabue and Pletcher concerning the aberrant morphology of the septal submucosal glands and the reduced production of mucin in chronic rhinosinusitis (CRS). 1 In fact, there is growing interest regarding the alterations of nasal secretions in patients with rhinitis as defective mucociliary clearance (MCC) seems to play a crucial role in the pathogenesis of CRS. As highlighted by the authors, the protective mucous layer, the airway surface liquid layer, and the cilia of the respiratory epithelium are the three functional components of the MCC apparatus, which represents the primary innate defense mechanism of the upper respiratory system.…”