Vascular permeability of the middle ear mucosa in otitis media with effusion.

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.