Catabolism of Glycoconjugates in Chronic Otitis Media with Cholesteatoma

Abstract

Chronic ear disease with cholesteatoma is characterized by an intrusion of keratinizing stratified squamous epithelium into the middle ear manifesting bone resorption at the interface of the perimatrix. The aim of our study was to investigate the markers of a catabolic process associated with several chronic inflammatory states. We assessed the level of catabolism of glycoconjugates in assays of cholesteatoma extracts, quantifying two lysosomal exoglycosidases: alpha-mannosidase (alpha-MAN) and beta-galactosidase (beta-GAL). Cholesteatomas (n = 15) and normal adult postauricular skin served as controls (n = 15) were collected from the patients during surgery owing to chronic otitis media. To assess exoglycosidase activity, release of p-nitrophenol from p-nitrophenol derivatives of alpha-mannose and beta-galactose was used. In 13 of 15 specimens, we observed significantly higher activity of investigated enzymes in cholesteatoma tissue compared with control tissue (postauricular skin). The mean activity of alpha-MAN from the cholesteatoma cells was 1.76 +/- 1.10 nkat/g wet tissue and 0.61 +/- 0.21 nkat/g wet tissue in the control probes. The mean activity of beta-GAL from the cholesteatoma cells was 1.77 +/- 1.07 nkat/g wet tissue and 0.87 +/- 0.20 nkat/g wet tissue in the control probes. Catabolic reactions involving glycoproteins, glycolipids, and proteoglycans may play a role in cholesteatoma-related bone resorption. The present data indicating that the lysosomal exoglycosidases alpha-MAN and beta-GAL are significantly and consistently elevated suggest the need to further correlations assessment between levels of alpha-MAN and beta-GAL and cholesteatoma behavior. Further research should also evaluate the relative importance of these particular exoglycosidases in manifesting bone resorption in considering the spectrum of identified inflammatory mediators.

Possible role of α-mannosidase and β-galactosidase in larynx cancer

“…N -acetyl-β-D hexosaminidase (HEX), in larynx cancer and chronic otitis media with cholesteatoma [19–21]. The increase in HEX activity was observed in several inflammatory diseases, such as rheumatoid arthritis, idiopathic juvenile arthritis, osteoarthritis and chronic glomerulonephritis, as well as tumours, e.g.…”

“…In our previous paper we presented the activity of N -acetyl-β-glucosaminidase (hexosaminidase) in laryngeal cancer and cholesteatoma [19–21] and now in the present investigation, for the first time, we investigated the activities of α-mannosidase and β-galactosidase in larynx cancer, performing identical, blinded assays in normal tissue biopsies taken from macroscopically healthy tissue during the same total laryngectomy. We also demonstrated the correlation between the activities of investigated enzymes in larynx cancer and healthy tissue specimens.…”

Possible participation of acidic pH in bone resorption in middle ear cholesteatoma

“…Since the 1970s, a variety of cytokines, chemical mediators, and enzymes have been detected in cholesteatoma tissue, and these factors have been reported as possibly causative of bone resorption. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] However, the etiopathology of this aggressiveness remains controversial. In the present study, we examined pH in middle ear cholesteatoma tissue and the permeability of the cholesteatoma epithelium in an attempt to elucidate the mechanism of bone resorption in this disease.…”

Increased permeability of the epithelium of middle ear cholesteatoma

“…Since the 1970s, a variety of cytokines, chemical mediators and enzymes have been detected in cholesteatoma tissue, and these factors have been reported as possible causative factors of the bone resorption. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] However, the etiopathology of the aggressive nature of cholesteatoma remains controversial. We recently showed that the acidic pH of the cholesteatoma tissue may participate in the bone resorption.…”