Expression of Major Basic Protein and Endothelial Adhesion Molecules in Chronically Inflamed Mucosa of the Ethmoid Labyrinth

Abstract

Background/Objectives

Tissue remodeling, including dense eosinophil infiltration, is essential for forming inflammatory nasal polyps (NPs) and the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). Toxic eosinophil major basic protein (MBP) damages the sinus mucosa epithelium and lamina propria, which initiates reparative processes leading to tissue remodeling. MBP specifically binds to BMK-13 antibodies allowing immunohistochemical (IHC) tissue staining for eosinophils. This study evaluated the association between NP stromal BMK-13 and endothelial adhesion molecule staining, and clinical parameters of NP patients compared to IHC expression and clinical parameters in subjects with healthy nasal mucosa.

Methods

We included 30 patients with bilateral NPs who were selected for endoscopic ethmoidectomy. The control group was of 30 subjects with non-inflamed nasal mucosa but with middle turbinate aeration, chosen for surgery. All participants were clinically scored before surgery, according to quality of life (QoL) outcome and symptoms. The degree of disease extension on computed tomography scans of the paranasal sinuses was also evaluated. Tissue samples after surgery were IHC stained for BMK-13 and endothelial proliferation markers CD31 and CD34.

Results

Expression of BMK-13, CD31, and CD34 in tissues of NPs was higher than in healthy nasal mucosa. Positive correlations were observed between BMK-13 expression, impaired QoL, and radiologically assessed extension of inflammation in NP patients.

Conclusion

Apart from the fact that the NP tissue has, as expected, more intense eosinophilic infiltration, the proliferation of blood vessels is more pronounced in the NP tissue than in the tissue of healthy nasal mucosa. Expression of MBP in the tissue of ethmoidal NPs could serve as a potential marker of the degree of expansion of CRSwNP and indicate the severity of the disease.

Clinical Trial Registration

None, because it was a cross-sectional study.