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Endotoxin and lysosomal protease activity in acute and chronic otitis media with effusion
K Sakakura1, Y Hamaguchi, T Harada
1Department of Otorhinolaryngology, Mie University School of Medicine, Tsu, Japan.
Abstract:
Endotoxin levels and lysosomal protease (collagenase, cathepsin B, and lysozyme) activity were measured in 104 middle ear effusions (MEEs) from patients with otitis media with effusion (OME). The MEE samples were classified into four groups: pediatric serous, mucoid, and acute, and adult serous. Endotoxin levels and lysosomal protease activity in MEEs were significantly different in the following order: adult less than serous less than mucoid less than acute groups, indicating that both endotoxin and lysosomal proteases are more closely related to the pathogenesis of pediatric chronic OME than to adult OME. In pediatric serous and mucoid effusions, endotoxin level had a significant correlation with activity of the lysosomal proteases. In conclusion, endotoxin enhances leukocyte infiltration into the middle ear, and lysosomal proteases released from leukocytes damage the middle ear mucosa and thereby prolong mucosal inflammation, which may be responsible for delayed recovery from acute OME.
Insights
Endotoxin and lysosomal proteases are key factors in pediatric chronic otitis media with effusion (OME). Higher levels in pediatric effusions suggest a role in prolonged middle ear inflammation and delayed recovery.
Area of Science:
- Otolaryngology
- Immunology
- Pathology
Background:
- Otitis media with effusion (OME) is a common condition, particularly in children.
- Understanding the inflammatory mechanisms in OME is crucial for effective treatment.
Purpose of the Study:
- To investigate the role of endotoxin and lysosomal protease activity in the pathogenesis of OME.
- To compare these factors in different types of middle ear effusions (MEEs) across pediatric and adult populations.
Main Methods:
- Measurement of endotoxin levels and lysosomal protease (collagenase, cathepsin B, lysozyme) activity in 104 MEE samples.
- Classification of MEEs into pediatric serous, mucoid, acute, and adult serous groups.
Main Results:
- Endotoxin and protease activity levels were significantly higher in pediatric OME effusions compared to adult effusions, following the order: adult < serous < mucoid < acute.
- A significant correlation between endotoxin levels and lysosomal protease activity was observed in pediatric serous and mucoid MEEs.
Conclusions:
- Endotoxin and lysosomal proteases are more implicated in the pathogenesis of pediatric chronic OME than adult OME.
- Endotoxin promotes leukocyte infiltration, while proteases from leukocytes damage middle ear mucosa, prolonging inflammation and potentially delaying recovery from acute OME.