Role of interleukin-1beta in a murine model of otitis media with effusion.

To clarify the role of interleukin-1beta (IL-1beta) in the pathogenesis of otitis media with effusion (OME), we developed and investigated a murine model of this disease. Specific pathogen-free male BALB/c mice received intratympanic injections of 20 microg of endotoxin derived from nontypeable Haemophilus influenzae. Three days after injection, middle ear effusions were observed through the eardrum. Similar pathological changes were observed after inoculation with 100 ng of recombinant IL-1beta. Anti-IL-1 receptor antibodies inhibited the pathological changes induced by the endotoxin. In situ hybridization showed expression of IL-1beta messenger RNA in the epithelium of the middle ear mucosa. These results suggest that IL-1beta might be associated with endotoxin-induced inflammation in the middle ear and might play an important role in the induction of otitis media with effusion.     

Quantitative analysis of the bacterial findings in otitis media

Qualitative and quantitative bacterial analysis of 200 samples of middle ear effusions collected from patients with current otitis media was performed. When middle ear pathogens (S. pneumoniae, H. influenzae and B. catarrhalis) were found during current acute otitis media or otitis media with effusion infection, the quantity of these bacteria was of the magnitude 10(6)-10(8)/ml and 0-5 x 10(5)/ml effusion material, respectively. Mucopurulent effusion material contained 6 x 10(5)-10(8) bacteria per ml whereas effusion from chronically discharging ears exceeded 10(9) bacteria per ml. Serous effusions did not harbour middle ear pathogens. The appearance of the effusion material was dependent on the number of bacteria involved. Quantification of bacteria in various middle ear effusions offers opportunities to make the diagnosis of various otitis media infections more accurate and readily comparable.     

分泌性中耳炎渗出液的细胞因子检测

目的 :探讨分泌性中耳炎渗出液中细胞因子的水平及其炎症的调节机制。方法 :用 EL ISA法检测本病患耳的渗出液中肿瘤坏死因子 -α(TNF-α)和可溶性肿瘤坏死因子受体 (TNFsol R )水平 ,分析其与临床指标间的关系。结果 :渗出液中 TNF- α和 TNFsol R 的检出率均为 10 0 % ;TNF- α值为 (3.42± 2 .2 5 ) ng/ g总蛋白 ,TNFsol R 为 (4 0 5 .80± 2 16 .5 3) ng/ g总蛋白 ,TNFsol R 指数为 (15 4.18± 90 .45 ) U;多次发病的患者 TNFsol R 和 TNFsol R 指数均降低 (P <0 .0 5 )。结论 :细胞因子 TNF- α和 TNFsol R 存在于所有分泌性中耳炎渗出液中 ,是此炎症反应的重要递质。复发的分泌性中耳炎渗出液中 TNFsol R 和 TNFsol R 指数明显降低 (P <0 .0 5 ) ,而 TNF- α无明显变化。     

Biochemical evidence of platelet-activating factor (paf) in human middle ear effusions

Platelet-activating factor (PAF) is one of the most potent biological lipid mediators. This is especially true in relation to inflammation. In order to characterize the biochemical features of otitis media with effusion, the authors characterized and determined the concentration of the PAF present in human middle ear effusions obtained from 23 patients with otitis media with effusion. Each sample of middle ear effusion was divided into two groups: serous (n = 12) and mucoid effusions (n = 11). The platelet-activating factor activity was found mainly in mucoid middle ear effusions, and the amounts of PAF were higher in mucoid type (3.55 ± 1.19 ng/g, mean ± standard deviation [SD]) than in the serous type (0.44 ± 0.19 ng/g). Phospholipids obtained from the middle ear effusions contained a large amount of lyso-platelet-activating factor, the biologically inactive precursor or breakdown product of platelet-activating factor. Based on these findings, it is suggested that platelet-activating factor may play an important role as a mediator of the inflammatory responses in the pathogenesis of otitis media with effusion.     

Bacterial quantification--a necessary complement for the comprehension of middle ear inflammations.

Quantification of bacteria in various types of middle ear effusion (MEE) obtained during current acute otitis media (AOM), otitis media with effusion (OME) and chronic suppurative otitis media (COM) was performed. The bacteria were stained with acridine orange and their number per ml effusion evaluated under the fluorescence microscope according to a method described in detail elsewhere. During AOM, 53% of the MEE samples were culture-positive and contained 10(6)-10(8) bacteria per ml (median value 10(7) per ml). During OME, serous effusion and 78% of the mucoid effusions contained no bacteria whatsoever, whereas the remaining mucoid effusions contained 10(4)-5 x 10(5) bacteria per ml (median value 10(4) per ml). Mucopurulent effusions contained 6 x 10(5)-10(8) bacteria per ml (median value 5 x 10(6) per ml). During COM, purulent MEE had 6 x 10(6)-10(9) bacteria per ml (median value 10(8) per ml). Quantification of bacteria involved in middle ear diseases provides further information about the etiopathogenesis and appropriate management of various pathological conditions of the middle ear.     

Otologic manifestations of experimental rhinovirus infection

Episodes of acute otitis media are commonly associated with viral upper respiratory tract infections. Rhinoviruses account for approximately 40% of these infections, and were previously shown to alter eustachian tube function and middle ear pressures. However, progression to otitis media has not been prospectively documented. In the present study, changes in tympanometric pressures and otoscopic findings resulting from experimental intranasal rhinovirus type-39 inoculation were documented in 60 adult volunteers. Fifty-seven (95%) subjects became infected and 34 (60%) of these had a clinical cold. Prior to viral inoculation, 3 (5%) subjects had middle ear pressures of less than ?100 mm H₂O and two of these subjects developed middle ear effusions following infection. In all, 22 (39%) subjects developed middle ear pressures of less than ?100 mm H₂O. No subject with normal middle ear pressures prior to infection developed evidence of effusion. This study extends the otologic manifestations of rhinovirus infection to include otitis media. Furthermore, these results support the hypothesized relationship between upper respiratory tract infections, eustachian tube dysfunction, and otitis media.     

Experimental otitis media with effusion induced by middle ear effusion.

Experimental otitis media with effusion was induced in chinchillas by middle ear effusion, which was induced by an injection of immune complex into the tympanic cavity. To elucidate the pathogenesis of otitis media with effusion, cytologic and biochemical findings of the effusion and histopathology of the middle ear mucosa of effusion-induced chinchillas were compared with those of experimental otitis media with effusion induced by different procedures; eustachian tube obstruction, intratympanic inoculation of endotoxin, and immune reaction. No significant differences were seen in cytology, biochemistry, and histopathology among OMEs induced by these procedures. However, middle ear effusions, when compared with the corresponding sera, were proven to contain higher amounts of histamine and prostaglandin E2. These findings seem to demonstrate that middle ear effusion containing a large number of inflammatory mediators is essential for induction and prolongation of inflammatory reaction in the middle ear.     

Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae: mucociliary pathology of the middle ear

We inoculated 100 micrograms/ml of lipopolysaccharide (LPS) from Klebsiella pneumoniae into the tympanic cavity of guinea pigs and examined the mucociliary pathology in the middle ear. Serous effusion was observed in the tympanic cavity of every animal on the first, third, and seventh day following the procedure, but the volume of the effusion had decreased to 0.2 ml on day 7. By that time, the ciliary activity in the opening to the eustachian tube within the middle ear had recovered to some extent, but in the middle ear distal to the opening no recovery was apparent. Our results show that cilia close to the eustachian tube play a more significant role in middle ear clearance than those in the middle ear distal to the tube. Compared with our previous study using 10 micron/ml of LPS, this study also demonstrates that inoculations with a higher concentration of LPS induces longer-term middle ear effusions.     

Ciliary beat frequency of nasal and middle ear mucosa in children with otitis media with effusion

Impaired mucociliary function of respiratory tract mucosa is associated with secretory otitis media in some well recognized syndromes. Ciliary activity per se may now be assessed directly by determination of ciliary beat frequency by a photoelectric technique.^1,2 49 children with otitis media with effusion undergoing surgical treatment were studied. Middle ear mucosa and nasal epithelial cells were obtained by biopsy and cytological brushings respectively at the time of surgery (myringotomy ± grommet insertion under general anaesthesia). From these samples mean nasal ciliary beat frequency was 11.0 Hz and mean middle ear ciliary beat frequency was 11.2 Hz. A positive correlation exists between mean ciliary beat frequency of nasal and middle ear samples from individual patients. A comparison of mean ciliary beat frequency between children who were effusion positive and effusion negative at the time of surgery revealed no statistically significant difference. In addition, no difference existed between those children with recurrent otitis media with effusion and newly presenting cases. No prima facie evidence exists of impaired ciliary function in this population of children with otitis media with effusion.     

Physicochemical properties of human middle ear effusions (mucus) and their relation to ciliary transport.

Middle ear effusions were collected from 10 patients (14 ears) with secretory otitis media. Mucoid samples were pooled and reconstituted to various concentrations of nondialyzable solids. Viscoelasticity was studied using a magnetic microrheometer and compared with mucociliary transport rates measured on the frog palate. Results indicate that the viscoelastic properties of middle ear mucus correlate with mucociliary transport. A transport maximum was found at a 2% nondialyzable solids content. Implications relative to ineffective mucociliary transport in secretory otitis media are discussed.     

Otitis media with effusion: Specific antibody activities against exotoxins in middle ear effusions

Findings of recent immunologic studies on otitis media with effusion indicate that antibodies in middle ear effusions can either originate from serum and/or from local production in the middle ear cavity and Eustachian tube. Determination of specific antibody activity of different immunoglobulin classes in effusions and sera against certain bacterial antigens may aid in a better understanding of the pathogenesis of otitis media with effusion. A radioimmunosorbent assay was employed in the present study to determine specific antibody activity against streptolysin or staphylolysin. Although these antibody activities were mainly limited to IgG and IgA class antibodies in effusion as well as in serum, it was also found that SIgA of various types of the effusion possesses the antibody activity against these exotoxins. Findings of this study suggest that a local immunity functions in the middle ear cavity of patients with otitis media with effusions and that bacterial infection may contribute to the development of middle ear effusion in certain cases.     

Compositional difference in middle ear effusion: mucous versus serous.

OBJECTIVES: Serous otitis media is usually responsive to medical treatment, whereas mucoid otitis media is not. The present study was undertaken to elucidate the compositional difference between serous and mucoid effusion and to investigate whether MUC5AC acts as a major mucin in the middle ear mucosa with mucoid otitis media. STUDY DESIGN: This study involved a chemical analysis of middle ear effusion and immunostaining of the middle ear mucosa. METHODS: Middle ear effusion samples were collected from 27 patients with mucoid otitis media and 18 patients with serous otitis media. The levels of mucin, lysozyme, secretory immunoglobulin A, and interleukin-8 were measured by dot blotting or enzyme-linked immunosorbent assay. Periodic acid-Schiff and immunohistochemical staining with monoclonal anti-MUC5AC antibody were performed on the serial sections of middle ear mucosa with mucoid otitis media. RESULTS: Mucoid effusions contained higher levels of mucin, lysozyme, secretory immunoglobulin A, and interleukin-8 than did serous effusions. Immunohistological study revealed that MUC5AC mucin was expressed in only a small portion of the goblet cells of middle ear mucosa with mucoid otitis media. CONCLUSIONS: The study suggests that both serous secretions and mucin might make the middle ear effusion more viscous and that mucins other than MUC5AC might have a major role in the viscosity of middle ear effusion. Further study is necessary to identify the major mucins in the middle ear effusion of otitis media with effusion.     

Mucociliary disease of the middle ear during experimental otitis media with effusion induced by bacterial endotoxin

Lipopolysaccharide (10 micrograms/mL) derived from Klebsiella pneumoniae was injected into the middle ear of guinea pigs. The animals were killed painlessly on days 1, 3, and 7 after inoculation, and the mucosal samples from two sites within the tympanic cavity, close to the tympanic orifice and distal to the orifice, were examined for ciliary activity and epithelial morphology. At day 1 and day 3 serous effusion was observed and deterioration of ciliary activity and morphologic changes were observed. No effusion was recognized at day 7, when the ciliary activity in the distal mucosa was still diminished and that in the proximal mucosa had recovered to a normal level. Our data have shown that lipopolysaccharide extracted from K pneumoniae can produce otitis media with effusion in laboratory animals, and dysfunction of cilia due to lipopolysaccharide probably is responsible for the accumulation of middle ear effusion. The mucociliary system is indeed an important defense system and failure of such a system, especially in the mucosa close to the tympanic orifice, can cause the buildup of effusions.     

The quantitation of Pseudomonas aeruginosa elastase in suppurative chronic otitis media using a sensitive ELISA method]

A sensitive sandwich ELISA method has been developed in order to quantitate the Pseudomonas aeruginosa elastase (PE) of ear discharge from chronic suppurative otitis media (CSOM) patients. Samples were incubated with EDTA-2Na before ELISA in order to inhibit the PE activity which hydrolyzes anti-PE IgG antibody into smaller molecular fragments. Quantitation of PE in middle ear effusions (MEE) from 10 patients with chronic otitis media with effusion (OME) were also performed. In CSOM, 12 of 14 samples revealed a significant amount of PE from 0.6 microliter/ml to 62.1 microliters/ml, which was significantly higher than those in MEE (p less than 0.05). In MEE, 8 of 10 samples were under the detection limit. Two samples in CSOM with Pseudomonas aeruginosa infection had high levels of PE. The quantitation was linear, with a concentration from 5 ng PE/sample to 500 ng PE/sample. This ELISA system is a sensitive method for quantitation of PE requiring only very small samples.     

Influenza A virus-induced mucociliary dysfunction of tubotympanum]

There is amount of epidemiologic, clinical and laboratory evidence to document that viral infection is involved in otitis media with effusion (OME). However, few studies have demonstrated the direct influence of viruses on the tubotympanum. The purpose of this study is to establish the effect of influenza A virus invaded in the tubotympanum, in an attempt to elucidate the possible mechanism by which the virus contributes to the pathogenesis of OME. 80 guinea pigs with normal otoscopic findings were inoculated with 0.2ml suspension of influenza A (3.3 x 10(8)PFU/ml) into their tympanic cavities through their tympanic membranes. To serve as controls, the same number of guinea pigs were injected with 0.2ml of physiologic saline solution into their tympanic cavities. At 3, 7, 14, and 28 days postinoculation, they were used for examination of the mucociliary function. Middle ear effusions were observed only in the animals inoculated with the virus. Mucociliary dysfunction was observed only in the animals inoculated with the virus. The ciliary activity in the bulla was declined at any time examined. On the other hand, the ciliary activity in the eustachian tube and the tympanic orifice was slightly lowered between 7 and 14 days, but the level was not different from that of the control. However, the number of active ciliated cells (showing more than 500 beats/min) was significantly smaller than that of the control. The mucociliary clearance time of the tubotympanum was more prolonged than that of the control at 3, 7, and 14 days, and returned to the control level at 28 days. A variety of morphologic changes were observed in the tubotympanum treated with the virus. Major pathologies observed included a general inflammatory cell infiltration, vacuolation and other degeneration of ciliated cells, and vascular damage and increased vascular permeability. Regeneration of cilia or ciliated cells followed the degeneration, which included an increased number of basal cells and new formed centrioles. However, the viral infection had an influence on the epithelial cells with new centrioles. Our study has demonstrated that viral infection could evoke mucociliary dysfunction of the tubotympanum and create an increased susceptibility to bacteria. Therefore, viral infection could enhance bacterial infectious process in the tubotympanum. Through the failure viruses could contribute to the occurrence of OME.     

Lymphangioma of the middle ear and mastoid simulating chronic otitis media with effusion

Lymphangiomas are benign congenital malformations of the lymphatic system. Middle ear lymphangioma is extremely rare entity. A 14-year-old male patient with otitis media with effusion, which was previously diagnosed to be middle ear and mastoid lymphangioma, was treated. There were no cerebrospinal fluid fistula, solitary mass, and meningitis findings. All properties of chronic otitis media with effusion were present in that case. This case is unique with these clinical properties. Middle ear and/or mastoid lymphangioma should be remembered in the differential diagnosis of chronic middle ear effusions.     

Effect of bacterial endotoxin and middle ear effusion on ciliary activity: implications for otitis media

OBJECTIVES/HYPOTHESIS: Otitis media with effusion (OME) is the most common cause of childhood deafness. The pathogenesis is not fully understood, especially the reasons for failure of mucociliary clearance of the middle ear. It is not clear whether the cilia function normally in the middle ear and eustachian tube in the chronic phase of otitis media with effusion. However, impaired ciliary function in primary ciliary dyskinesia is known to be frequently associated with the development of otitis media with effusion. We hypothesized that endotoxin or the bacterial products in middle ear fluid in otitis media with effusion would adversely affect ciliary activity, thereby contributing to the pathogenesis of the disease. STUDY DESIGN: Laboratory-based study of human ciliary activity with reference to otitis media with effusion. METHODS: We have studied the activity of human adenoidal cilia under various conditions. Ciliary activity in the presence of Haemophilus influenzae endotoxin additions (at varying concentrations) to cultured adenoidal explants has been measured. In addition, ciliary activity of these explants was also observed after addition of middle ear effusion aspirated from patients. RESULTS: We have shown that endotoxin in concentrations far in excess of those found in the middle ear with chronic otitis media with effusion had no effect on ciliary activity. Furthermore, ciliary activity was completely unaffected by the presence of middle ear effusion. CONCLUSION: There is no evidence that ciliary activity is reduced by the constituents of middle ear fluid in chronic otitis media with effusion.     

Rheologic studies on middle ear effusions and their mucus glycoproteins

The properties of pooled thick and thin middle ear effusions, from children with otitis media with effusion, were studied by viscometry. Mucus glycoproteins were responsible for effusion viscosity. Their percentage by weight in thick and thin effusions was 25% and 8.2%, respectively. N-acetylcysteine and 0.2 mol/L of mercaptoethanol caused a 39% viscosity drop in a 5-mg/mL glycoprotein solution, whereas S-carboxymethylcysteine had no effect. Treatment of thick effusions with 0.2 mol/L of mercaptoethanol initially caused a viscosity decrease followed by a gradual increase. Higher reducing agent concentrations (0.5 mol/L) caused a more rapid decrease followed by a rapid increase, presumably by causing nonspecific aggregation of reduced protein molecules. These results suggest that the concentration of and the time that a mucolytic is in the middle ear would be of prime importance in achieving the desired decrease in viscosity.     

Detection of fungal DNA in effusion associated with acute and serous otitis media

OBJECTIVES/HYPOTHESIS: Routine bacterial and viral cultures of middle ear fluid are often negative, suggesting that other infectious agents may be involved. Because of the similarities between the paranasal sinuses and middle ear space and the recent recognition of fungi as important pathogens in inflammation of the paranasal sinuses, we investigated the potential role of fungi in acute otitis media and serous otitis media using culture and polymerase chain reaction techniques. STUDY DESIGN: Prospective study. METHODS: Middle ear effusions of 29 patients who underwent myringotomy and pressure equalization tube placement for persistent serous otitis media or recurrent acute otitis media were collected. Fungal culture of the effusion samples was performed on potato flake agar. DNA from the effusion was isolated using standard techniques. Polymerase chain reaction, using radiolabeled universal fungus primer for internal transcribed spacer of 5.8s ribosomal DNA, was performed to detect the presence of any fungal DNA in the samples. RESULTS: Culture of middle ear effusions showed no evidence of fungal growth. Polymerase chain reaction analysis was able to detect the constituent ribosomal DNA of a single fungal genome. Fungal DNA was present in 34% of middle ear effusion samples. CONCLUSIONS: Fungal DNA is present in recurrent acute otitis media and serous otitis media suggesting that it may play an etiological role in serous otitis media and acute otitis media. However, additional studies are necessary to delineate the role of fungi in the pathogenesis of otitis media.     

Prognosis of secretory otitis media in relation to viscoelasticity of effusions in children

Both elasticity (G') and viscosity (eta') of middle ear effusions (MEEs) were measured with an oscillating sphere magnetic rheometer and compared with continuance of fluid retention in 93 ears of 69 children with otitis media with effusion (OME). The ears were divided into four groups according to the viscoelastic properties of MEEs at the first myringotomy. Eight-four percent of the ears in group 2 were free from effusion within 4 months; the difference from the other groups was statistically significant. These results indicate that the mucociliary clearance function plays an important role in the process of recovery from OME.