Chronic rhinosinusitis is a difficult-to-treat disease that is often characterized by recurrent NP growth following surgical removal. NPs are composed in part of an inflammatory cellular infiltrate, blood vessels, and a large ECM amount. Despite the recognition of prominent ECM deposition, few studies have examined the components in detail and how they might differ with a disease state.

The purpose of this study was to quantitate the expression of ECM components in NPs.

Researchers stained NPs with pico-Sirius red to determine total collagen content, and immunofluorescence was used to detect collagen I, collagen III, collagen IV, fibronectin, and laminin. Collagen IV was not different among any groups, and researchers found its location predominately around vessels. When analyzed as a polyp eosinophil number, total collagen and collagen III showed a significant inverse correlation.

The study concluded that NP ECM composition differs with disease state with higher expression in cases where eosinophil levels are low. Findings suggest a loss of matrix deposition in eosinophilic polyps either through break down or a failure to produce the essential components. Understanding these differences may identify new therapeutic targets.