Topical glucocorticoids downregulate COX-1 positive cells in nasal polyps

Area of Science:

• Otorhinolaryngology
• Immunology
• Pharmacology

Background:

• Nasal polyposis (NP) is characterized by inflammatory cell infiltration.
• Glucocorticoids (GC) are widely used for NP treatment due to their anti-inflammatory properties.
• GC may exert effects by modulating prostanoid synthesis via cyclooxygenases (COX).

Purpose of the Study:

• To investigate the impact of topical glucocorticoids (GC) on cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) expression in nasal polyps (NP).
• To assess the effect of topical GC on key inflammatory markers within nasal polyps.

Main Methods:

• Immunohistochemical analysis was performed on normal nasal mucosa (NM), non-GC treated NP, and topical GC-treated NP.
• Evaluated inflammatory markers included CD68, CD117, eosinophils (MBP, elastase), IgE, IL-4, IL-5, and IL-6.
• Expression levels of COX-1 and COX-2 were quantified in all sample groups.

Main Results:

• Nasal polyps exhibited increased eosinophils, IL-5+ cells, and IgE+ cells, with decreased mast cells compared to normal mucosa.
• COX-1+ cells were significantly increased in NP epithelium relative to NM.
• Topical GC treatment significantly reduced COX-1+ cells in NP but did not alter COX-2+ cells.

Conclusions:

• Topical glucocorticoids effectively reduce COX-1 expression in nasal polyps.
• GC treatment did not significantly impact COX-2 expression or eosinophil counts in NP.
• Interestingly, IL-5+ cell counts were significantly increased following GC treatment in NP.