Otitis Media with Effusion: Components Which Contribute to the Viscous Properties

Abstract

Middle ear effusions from children undergoing myringotomy were classified into thick (mucoid) and thin (serous) on the basis of their flow properties. Their composition was analysed and their rheological properties measured. The viscosity of the effusions was measured using a Contraves low shear viscometer and expressed as specific viscosity per mg/ml of non-dialysable solids present. In order to measure the effusion viscosity it was necessary to solubilize the effusion by mild homogenisation in a phosphate buffer pH 6.7 containing a cocktail of proteolytic inhibitors. The viscosity of mucoid effusions was significantly greater than that of the serous effusions. There was a small but measurable amount of proteolytic activity in the effusions, range 0.05-1.79 micrograms/mg of non-dialysable solids. This proteolytic activity was not significantly different between the thick and thin effusions and was therefore unlikely to explain the difference in viscosity. Analysis of the constituents of the effusions showed that glycoprotein and DNA but not protein nor lipid were significantly higher in the mucoid effusions compared to the serous effusions. The viscosity of the effusions correlated with the glycoprotein concentration but not with the protein or lipid concentration. Under certain circumstances the DNA concentration did correlate with the viscosity of the effusion. However, digestion with a proteinase free DNase did not reduce the viscosity of the effusion. These results demonstrate that classifying effusions as thick and thin based on visual inspection and flow properties is valid and that the only constituent present in the effusions that determines viscosity is mucin.

Transforming Growth Factor-β-Smad Signaling Pathway Negatively Regulates Nontypeable Haemophilus influenzae-induced MUC5AC Mucin Transcription via Mitogen-activated Protein Kinase (MAPK) Phosphatase-1-dependent Inhibition of p38 MAPK

“…To date, 18 mucin genes have been identified (14 -17). Among these, at least MUC2, MUC5AC, and MUC5B have been shown to play an important role in the pathogenesis of respiratory infectious diseases (14,15,(17)(18)(19)(20)(21). We have demonstrated recently that TGF-␤-Smad * This work was supported by National Institutes of Health Grants DC004562, DC005843, and HL070293 (to J. D. L.), CA24321 (to Y. S. K. and J. G.), and GM63773 (to X.-H. F.) and a grant from the Department of Veterans Affairs Medical Research Service (to J. G. and Y. S. K.).…”

Transforming Growth Factor-β-Smad Signaling Pathway Cooperates with NF-κB to Mediate NontypeableHaemophilus influenzae-induced MUC2 Mucin Transcription

“…They protect the epithelial surface by binding and trapping inhaled infectious particles, including bacteria and viruses, for mucociliary clearance, at least in part because of the extraordinary diversity of their carbohydrate side chains (6,9). However, in patients with OM with effusion and COPD whose mucociliary clearance mechanisms have become defective, excessive production of mucin will lead to airway obstruction in COPD and conductive hearing loss in OM with effusion (8,10,11). To date, 14 mucin genes have been identified (9,10,12,13).…”

The Relation between Tympanostomy Tube Otorrhea and Types of Immune Cells in Middle Ear Effusion in Children with Otitis Media with Effusion

“…Goblet cells produce and secrete mucins, which are important glycoproteins in the mucociliary transport system of the middle ear and are the main component of middle ear effusions, responsible for the viscous properties of effusions. 51,52 However, under disease conditions, alterations that occur in the middle ear and eustachian tube mucin metabolism, 53 in the structure of mucin glycoproteins 54,55 and in the glycoconjugate expression in cilia and goblet cells 56 promote the dysfunction of the normal mucociliary transport system and the formation of effusion in the middle ear cleft. The expression of several mucins has been detected in OME.…”