Abstract
OBJECTIVE
To determine if chronic rhinosinusitis (CRS) correlates with alteration in the mucosal epithelial barrier, or with abundance of water membrane permeability proteins (including aquaporins).
METHOD
This is an open label study that involved 10 patients with CRS undergoing endoscopic sinus surgery and healthy control patients. Mucosal samples were collected and examined by H&E, immunohistology and real-time PCR (rt-PCR). The expression of barrier proteins (including E-cadherin, and occludin, as well as Septin-2, a novel protein implicated in monolayer barrier function) and aquaprorins (AQPs) was evaluated using western blotting. Aquaporins are water-specific membrane channel proteins that affect trans-epithelial water permeability and participate in a wide array of physiologic processes.
RESULTS
We have found a statistically significant increase in baseline AQP5 abundance in CRS mucosa, as compared to healthy controls. Other known proteins altering tight junction function, including E-cadherin, occludin and Septin-2, showed no evidence of consistent changes in membrane protein expression. Mucosa from the same patients was examined by H&E histology, evaluating tissue edema and polypoid changes. We demonstrate for the first time increased abundance of Aquaporin 5 (AQP5) in CRS, as compared to control, indicating increased nasal mucosa paracellular permeability. This observation correlates with the histological changes of membrane remodeling, tissue edema and basement membrane thickening.
CONCLUSION
This study confirms the previously suggested hypothesis that altered barrier function is implicated in the pathophysiology of CRS. Aquaporins may contribute to nasal mucosal edema and may play a role in the pathophysiology of CRS.