Hyaluronic acid is not up-regulated in nasal polyps

Abstract

Extracellular matrix in nasal polyps (NP) is characterized by a subepithelial infiltration of eosinophils and pseudocyst formation. Hyaluronic acid (HA) occupies a large place in extracellular space. Local deposition of glycosaminoglycans (GAGs), such as HA, by impairing the tissue viscosity, could promote this pseudocystic formation. Hyaluronic acid was measured in nasal tissue (n=15) and NP (n=16) by radioimmunoassay (RIA). In the group of polyp patients, 11 did not receive any treatment while 5 were treated by oral corticosteroids. On the other hand, immunohistochemistry against biotinylated hyaluronic acid binding protein was performed on polyps and normal tissue sections. Hyaluronic acid levels were not different between polyp patients and controls or between treated and nontreated patients. Immunostaining for hyaluronic acid was homogeneous in normal nasal mucosa, whereas in the core of NP, a network-like organization can be demonstrated. This is the first study on staining the hyaluronic acid in respiratory mucosa and showing the internal reorganization of GAGs inside nasal polyps.