Expression of glycoconjugates in human eustachian tubes with otitis media.
OBJECTIVE
To characterize glycoconjugate expression in normal human eustachian tubes and study the alterations in glycoconjugate expression found in eustachian tubes with otitis media.


METHODS
Using lectin histochemistry, alterations in glycoconjugates were studied in three normal temporal bones, in four temporal bones with mucoid otitis media (MOM), and in five with serous otitis media (SOM).


METHODS
Sections of previously processed temporal bones were decelloidinized, and then incubated with seven biotinylated lectins--WGA, SNA, MAA, BPA, PNA, UEA-1, and LcH--that reflect seven carbohydrate residues of glycoconjugates, respectively: GlcNAc/NeuNAc, NeuNAc alpha(2-6)GalNAc, NeuNAc alpha(2-3)GalNAc, Gal beta(1-3) GalNAc, L-fucose, and alpha-mannose residues. Control sections were incubated with inhibitory carbohydrates or without biotinylated lectins.


RESULTS
In the normal temporal bones, five carbohydrate residues in goblet cells and cilia of the eustachian tube demonstrated moderate to strong activity--NeuNAc alpha(2-6)GalNAc, NeuNAc alpha(2-3)GalNAc, GalNAc, Gal beta(1-3)GalNAc, and L-fucose. Two residues demonstrated weak activity--GlcNAc/NeuNAc and alpha-mannose. Temporal bones with MOM revealed increases in sialic acid and alpha-mannose, and a decrease in L-fucose. Residues of carbohydrates in the cilia of bones with SOM were notably decreased, especially for GalNAc, Gal beta(1-3)GalNAc, and NeuNAc alpha(2-6)GalNAc.


CONCLUSIONS
Glycoconjugates in the normal human eustachian tube are rich in GalNAc, Gal beta(1-3)GalNAc, L-fucose, and NeuNAc alpha(2-3/2-6) GalNAc, but low in alpha-mannose and sialic acid. Eustachian tubes from cases with SOM or MOM demonstrated alterations in glycoconjugate expression in cilia and goblet cells, which may reflect disorder of the carbohydrate metabolism during otitis media, especially in SOM.
University of Minnesota Otitis Media Research Center, Department of Otolaryngology, University of Minnesota School of Medicine, Minneapolis, USA.
M
M
Sone
M M
MM
Paparella
P A
PA
Schachern
N
N
Morizono
C T
CT
Le
J
J
Lin
D005064:Eustachian Tube / Q000378:metabolism*; D006001:Glycoconjugates / Q000378:metabolism*; D006651:Histocytochemistry; D006801:Humans; D010033:Otitis Media / Q000378:metabolism*; D010034:Otitis Media with Effusion / Q000378:metabolism; D013701:Temporal Bone / Q000166:cytology / Q000378:metabolism
D006001:Glycoconjugates