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Vascular permeability of the middle ear mucosa in otitis media with effusion
1Department of Otolaryngology, University of Minnesota, Minneapolis 55414.
Abstract:
Vascular permeability (VP) of the middle ear mucosa (MEM) in chronic otitis media with effusion (OME) was estimated in both pediatric and adult patients by calculating the middle ear effusion (MEE) to serum concentration ratios of albumin and of four protease inhibitors: alpha 1-antitrypsin (alpha 1-AT), alpha 1-antichymotrypsin (alpha 1-X), inter-alpha-trypsin inhibitor (I-alpha-I) and alpha 2-macroglobulin (alpha 2-M). The levels of albumin and alpha 1-AT in MEE were higher while those of I-alpha-I and alpha 2-M were lower than their serum levels in both adult serous and pediatric mucoid groups. There was a negative correlation between molecular weight and the mean value of the ratio (MEE/serum) of the four inhibitors in both serous (r = -0.989) and mucoid (r = -0.924) groups. Vascular permeability of the MEM seems to be variable in both serous and mucoid groups during middle ear inflammation. Selective leakage of proteins by molecular weight appears to occur in MEM. Our findings further indicate that a high level of the high-molecular-weight inhibitor alpha 2-M in MEE may be a significant index reflecting the remarkably enhanced VP of the MEM.
Insights
Vascular permeability in the middle ear mucosa (MEM) during otitis media with effusion (OME) varies by protein size. Higher levels of larger proteins like alpha 2-macroglobulin in middle ear effusion indicate increased MEM permeability.
Area of Science:
- Otolaryngology
- Pathophysiology
- Biochemistry
Background:
- Chronic otitis media with effusion (OME) involves inflammation and fluid accumulation in the middle ear.
- Understanding the mechanisms of fluid and protein leakage in the middle ear is crucial for OME management.
Purpose of the Study:
- To estimate vascular permeability (VP) of the middle ear mucosa (MEM) in pediatric and adult OME patients.
- To investigate the relationship between protein leakage and molecular weight in middle ear effusion (MEE).
Main Methods:
- Calculated MEE to serum concentration ratios for albumin and four protease inhibitors (alpha 1-antitrypsin, alpha 1-antichymotrypsin, inter-alpha-trypsin inhibitor, alpha 2-macroglobulin).
- Analyzed protein levels in MEE and serum from pediatric and adult OME patients.
Main Results:
- Albumin and alpha 1-antitrypsin levels were higher in MEE compared to serum.
- Inter-alpha-trypsin inhibitor and alpha 2-macroglobulin levels were lower in MEE compared to serum.
- A negative correlation was observed between molecular weight and MEE/serum ratios for the inhibitors, suggesting selective protein leakage.
Conclusions:
- Middle ear mucosa vascular permeability is variable in OME, with selective protein leakage occurring based on molecular weight.
- Elevated levels of alpha 2-macroglobulin in MEE may serve as a key indicator of significantly increased MEM vascular permeability.