Characterization of cytokines present in middle ear effusions

Benign paroxysmal positional vertigo and asymmetric hearing loss: is the worst hearing ear likely to suffer from otoconial displacement?

PURPOSE

Benign paroxysmal positional vertigo (BPPV) may be found in patients complaining of hearing disorders. The aim of our investigation was to describe audiological findings in BPPV patients, focusing on subjects with asymmetric hearing loss (AHL), to better understand whether otoconial displacement may occur preferentially in the worst hearing ear.

METHODS

A prospective study was performed on 112 BPPV patients. We divided the sample into subjects who suffered from AHL (G1) and patients with did not (G2). Data regarding vestibular symptoms, tinnitus, migraine, antivertigo drug therapy, and vascular risk factors were collected.

RESULTS

Out of 30 AHL subjects, 83.33% of them were affected by sensorineural hearing loss (SNHL) in at least one ear, with a significant difference in the distribution of hearing loss type between groups (p = 0.0006). In 70% of cases, the ear affected by BPPV was the one with the worst hearing threshold (p = 0.02); threshold asymmetry predicted BPPV in the worst hearing ear (p = 0.03). The predictability depended neither on the hearing threshold gap between ears nor the severity of the hearing threshold in the worst ear (p > 0.05). No differences in vascular risk factors between groups were observed (p > 0.05). We evidenced a moderate correlation between age and hearing threshold (ρ = 0.43). Age did not result a predictive factor for residual dizziness or BPPV in the worst ear (p > 0.05).

CONCLUSIONS

Our study supports the likelihood of an otoconial displacement in the worse hearing ear in BPPV patients. Clinicians should start testing the worst hearing ear when managing AHL patients with suspected BPPV.

Application of Propolis in Protecting Skeletal and Periodontal Health-A Systematic Review

Chronic inflammation and oxidative stress are two major mechanisms leading to the imbalance between bone resorption and bone formation rate, and subsequently, bone loss. Thus, functional foods and dietary compounds with antioxidant and anti-inflammatory could protect skeletal health. This review aims to examine the current evidence on the skeletal protective effects of propolis, a resin produced by bees, known to possess antioxidant and anti-inflammatory activities. A literature search was performed using Pubmed, Scopus, and Web of Science to identify studies on the effects of propolis on bone health. The search string used was (i) propolis AND (ii) (bone OR osteoporosis OR osteoblasts OR osteoclasts OR osteocytes). Eighteen studies were included in the current review. The available experimental studies demonstrated that propolis could prevent bone loss due to periodontitis, dental implantitis, and diabetes in animals. Combined with synthetic and natural grafts, it could also promote fracture healing. Propolis protects bone health by inhibiting osteoclastogenesis and promoting osteoblastogenesis, partly through its antioxidant and anti-inflammatory actions. Despite the promising preclinical results, the skeletal protective effects of propolis are yet to be proven in human studies. This research gap should be bridged before nutraceuticals based on propolis with specific health claims can be developed.

Neutrophil-lymphocyte and platelet-lymphocyte ratios in otitis media with effusion in children: Diagnostic role and audiologic correlations

AIM

To investigate the relationship between hearing loss and complete blood count parameters including neutrophil, lymphocyte, platelet (PLT), mean platelet volume (MPV), neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) in children with otitis media with effusion (OME).

MATERIALS-METHOD

The study group was formed by 244 paediatric patients who underwent ventilation tube placement because of OME, and was split into two groups as serous and mucoid. The control group included 112 individuals who have no hearing problems. Hearing levels were determined with pure tone audiometry in the study group, preoperatively, and control group. The blood parameters were compared between the serous, mucoid and control groups. The correlation analysis was performed between the blood parameters and hearing levels in the study group. The blood parameters were compared between the groups identified by hearing loss classification.

FINDINGS

There were significant negative correlations between hearing levels and each of NLR, PLR and MPV. There were significant positive correlations between hearing levels and each of the lymphocyte and PLT. According to the receiver operating characteristic (ROC) curves, serous OME can be estimated with 68% sensitivity and 61% specificity by the NLR value more than 1.1, and 77% sensitivity and 77% specificity by the PLR value more than 102.4. The ROC curve revealed that slight hearing loss could be estimated with 70% sensitivity and 73% specificity by the NLR value more than 1.31, and 78% sensitivity and 77% specificity by the PLR value more than 102.4.

CONCLUSION

The present study revealed that NLR and PLR values were valuable parameters in the diagnosis of serous OME and predicting a hearing loss. These parameters may provide additional information to the audiogram that could influence the therapeutic decision.

Evaluation of Caspase-1, Interleukin-1β, and Interleukin-18, in the Middle Ear Effusion in Children With Otitis Media With Effusion

Objectives: The present study aimed to assess the expression of caspase-1 and caspase-1-dependent processing of cytokines, such as interleukin (IL)-1β and IL-18, in the middle ear effusion of children with otitis media with effusion (OME) in order to identify the potential role of inflammasomes in OME. Methods: This study included 29 children scheduled for myringotomy with the insertion of tympanostomy tubes due to OME. Middle ear effusion (MEE) was collected during the surgery. Caspase-1, IL-1β, and IL-18 were assayed using enzyme-linked immunosorbent assay kits. The levels were compared between those with mucoid and serous MEE and those with and without a history of ventilation tube insertion. Results: Caspase-1, IL-1β, and IL-18 were detected in all samples. The caspase-1, IL-1β, and IL-18 levels did not significantly differ between mucoid samples and serous samples. No statistical significances were discovered in caspase-1, IL-1β, and IL-18 levels between with and without a history of ventilation tube groups. There was a significant negative correlation between IL-1β and IL-18 and the duration of OME (p < 0.05). However, no significant correlation was found between caspase-1 and disease duration. Conclusions: Inflammasomes may participate in the inflammatory process of OME. IL-1β and IL-18 levels in the MEE decreased over time.

Asian Sand Dust Particles Increased Pneumococcal Biofilm Formation in vitro and Colonization in Human Middle Ear Epithelial Cells and Rat Middle Ear Mucosa

INTRODUCTION

Air pollutants such as Asian sand dust (ASD) and Streptococcus pneumoniae are risk factors for otitis media (OM). In this study, we evaluate the role of ASD in pneumococcal in vitro biofilm growth and colonization on human middle ear epithelium cells (HMEECs) and rat middle ear using the rat OM model.

METHODS

S. pneumoniae D39 in vitro biofilm growth in the presence of ASD (50-300 μg/ml) was evaluated in metal ion-free BHI medium using CV-microplate assay, colony-forming unit (cfu) counts, resazurin staining, scanning electron microscopy (SEM), and confocal microscopy (CF). Biofilm gene expression analysis was performed using real-time RT-PCR. The effects of ASD or S. pneumoniae individually or on co-treatment on HMEECs were evaluated by detecting HMEEC viability, apoptosis, and reactive oxygen species (ROS) production. In vivo colonization of S. pneumoniae in the presence of ASD was evaluated using the rat OM model, and RNA-Seq was used to evaluate the alterations in gene expression in rat middle ear mucosa.

RESULTS

S. pneumoniae biofilm growth was significantly (P < 0.05) elevated in the presence of ASD. SEM and CF analysis revealed thick and organized pneumococcal biofilms in the presence of ASD (300 μg/ml). However, in the absence of ASD, bacteria were unable to form organized biofilms, the cell size was smaller than normal, and long chain-like structures were formed. Biofilms grown in the presence of ASD showed elevated expression levels of genes involved in biofilm formation (luxS), competence (comA, comB, ciaR), and toxin production (lytA and ply). Prior exposure of HMEECs to ASD, followed by treatment for pneumococci, significantly (P < 0.05) decreased cell viability and increased apoptosis, and ROS production. In vivo experiment results showed significantly (P < 0.05) more than 65% increased bacteria colonization in rat middle ear mucosa in the presence of ASD. The apoptosis, cell death, DNA repair, inflammation and immune response were differentially regulated in three treatments; however, number of genes expressed in co-treatments was higher than single treatment. In co-treatment, antimicrobial protein/peptide-related genes (S100A family, Np4, DEFB family, and RATNP-3B) and OM-related genes (CYLD, SMAD, FBXO11, and CD14) were down regulated, and inflammatory cytokines and interleukins, such as IL1β, and TNF-related gene expression were elevated.

CONCLUSION

ASD presence increased the generation of pneumococcal biofilms and colonization.

High concentrations of middle ear antimicrobial peptides and proteins and proinflammatory cytokines are associated with detection of middle ear pathogens in children with recurrent acute otitis media

Recurrent and chronic otitis media (OM) are often refractory to antibiotics due to bacterial persistence in biofilm within the middle ear. In vitro and in vivo studies have demonstrated that antimicrobial proteins and peptides (AMPs) are bactericidal against otopathogens, indicating potential therapeutic value for recalcitrant OM. We measured concentrations of 6 AMPs and 14 cytokines in middle ear effusion (MEE) from 67 children undergoing ventilation tube insertion for recurrent acute OM. Sixty one percent of children had bacterial otopathogens detected in their MEE, 39% by PCR and 22% by PCR and culture. Groups were defined as: PCR-negative/culture-negative (absence of bacterial otopathogen), n = 26; PCR-positive/culture-negative (presence of nonculturable bacterial otopathogen), n = 26; PCR-positive/culture-positive (presence of culturable bacterial otopathogen), n = 15. Age, antibiotic usage, day-care attendance, presence of respiratory viruses in MEE and number of AOM episodes were similar between groups. AMP and cytokine concentrations were higher in children with bacterial otopathogens in their MEE compared to those with no bacterial otopathogens. Median concentrations of AMPs (except HBD2) were 3 to 56-fold higher in MEE from children with bacterial otopathogens detected in their MEE (P ≤ 0.01). Similarly, median cytokine concentrations (except TGFβ) were >16-fold higher in MEE with bacterial otopathogens detected (P ≤ 0.001). This is the first study to measure AMPs in MEE and together with the cytokine data, results suggest that elevated AMPs and cytokines in MEE are a marker of inflammation and bacterial persistence. AMPs may play an important role in OM pathogenesis.

Vitamin D and Otitis Media

PURPOSE OF REVIEW

To examine the relationship between vitamin D and otitis media.

RECENT FINDINGS

Vitamin D deficiency has been associated with several respiratory diseases, including otitis media. Vitamin D supplementation may reduce the risk of otitis media. This relationship may be explained by vitamin D supporting the immune system by upregulating antimicrobial peptides which are effective against otopathogens and biofilm formation, supporting a less inflammatory immune response, or promoting beneficial commensal bacteria. This review will explore risk factors of both otitis media and vitamin D deficiency, the evidence of vitamin D being beneficial for various forms of otitis media, and possible mechanisms of action.

Sensorineural hearing loss after otitis media with effusion and subacute mastoiditis after viral infections of the upper respiratory tract: A comparative study of conservative and surgical treatment

Involvement of the middle ear after viral infections of the upper airways may lead to serous otitis media with effusion in the absence of bacterial infection. This can be accompanied by a concomitant shading of the mastoid air cells, which could manifest as a reduced opacity on computed tomography (CT) in the absence of a history of chronic mastoiditis or acute inflammatory signs. This can lead to a subsequent impairment of inner ear function. CT scans reveal an extended pneumatization of the temporal bones in affected patients. Inner ear hearing impairment can probably be attributed to a concomitant labyrinthine reaction-the so-called toxic inner ear lesion. If no remission occurs within 5 days after initial conservative treatment (paracentesis or hemorrheologic infusions), surgical treatment with a mastoidectomy can accelerate hearing restoration. We conducted a retrospective, nonrandomized study of short- and long-term hearing outcomes in patients with a toxic inner ear lesion who had been treated with conservative measures alone (CONS group) or with surgery (SURG group) in a tertiary care referral center. Our study group was made up of 52 consecutively presenting patients (57 ears) who had been seen over a 10-year period; there were 20 patients (21 ears) in the CONS group and 32 patients (36 ears) in the SURG group. Initially, 15 CONS patients (75%) and 18 SURG patients (56%) complained of dizziness or a balance disorder. The initial averaged sensorineural hearing loss (over 0.5, 1.0, 2.0, and 3.0 kHz) was 32.4 ± 15.6 dB in the CONS group and 35.4 ± 12.0 dB in the SURG group. At follow-up (mean: 31.7 mo), the SURG group experienced a significantly greater improvement in hearing (p = 0.025). We conclude that patients with viral otitis media and concomitant noninflammatory mastoiditis with impairment of inner ear function (sensorineural hearing loss) experience a better hearing outcome when a mastoidectomy is performed during primary treatment.

Differences in innate immune response gene regulation in the middle ear of children who are otitis prone and in those not otitis prone

OBJECTIVE

Acute otitis media (AOM) causes an inflammatory response in the middle ear. We assessed differences in innate immune responses involved in bacterial defense at onset of AOM in children who were stringently defined as otitis prone (sOP) and children not otitis prone (NOP).

STUDY DESIGN

Innate immune genes analysis from middle ear fluid (MEF) samples of children.

METHODS

Genes of toll-like receptors (TLR), nod-like and retinoic acid-inducible gene-I-like receptors, downstream effectors important for inflammation and apoptosis, including cytokines and chemokines, were studied from MEF samples by using a real-time polymerase chain reaction array. Protein levels of differentially regulated genes were measured by Luminex.

RESULTS

Gene expression in MEF among children who were sOP was significantly different in upregulation of interleukin 8, secretory leukocyte peptidase inhibitor, and chemokine (C-C motif) ligand 3, and in downregulation of interferon regulatory factor 7 and its related signaling molecules interferon alpha, Toll-like receptor adaptor molecule 2, chemokine (C-C motif) ligand 5, and mitogen-activated protein kinase 8 compared with children who were NOP. Differences in innate gene regulation were similar when AOM was caused by Streptococcus pneumoniae or nontypeable Haemophilus influenzae.

CONCLUSION

Innate-immune response genes are differentially regulated in children who were sOP compared with children with NOP.

The suppressive effects of metformin on inflammatory response of otitis media model in human middle ear epithelial cells

OBJECTIVE

Metformin is a well-known anti-diabetic agent, but its mechanism is unclear. Recently, many reports have described the anti-inflammatory effects of metformin on various cell types, including human vascular smooth muscle cells and endothelial cells. This study was designed to investigate the anti-inflammatory effect of metformin on lipopolysaccharide (LPS) induced inflammation in human middle ear epithelial cell lines (HMEECs).

METHODS

The effect of pretreatment by metformin (0, 1, 2, 4 mM) was evaluated by the inflammatory response in the HMEECs exposed to LPS (10 ng/ml). For verifying the suppression effect of metformin on the inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) was evaluated by real-time polymerase chain reaction, and COX-2 protein was assessed by western blotting. Intracellular reactive oxygen species (ROS) was measured using 2', 7'-dichlorofluorescein diacetate (DCFHDA) fluorocytometer.

RESULTS

Stimulation by LPS 10 ng/ml concentration showed 12.4 folds increase the expression of TNF-α mRNA compared to control on HMEECs. Pretreatment of metformin dose dependently suppressed the expression of TNF-α mRNA induced by LPS (2 mM, p = 0.03). The amount of COX-2 protein production was significantly decreased by metformin pretreatment (4 mM, p = 0.01). The production of ROS was decreased significantly by pretreatment of metformin (p = 0.03).

CONCLUSIONS

These findings suggest that the inflammatory response and oxidative stress induced by LPS could be suppressed by metformin in HMEECs. Therefore, metformin may have a therapeutic potential for the treatment of the otitis media.

Pathogenesis and Bone Resorption in Acquired Cholesteatoma: Current Knowledge and Future Prospectives

Cholesteatoma is a cystic non tumorous lesion of the temporal bone that has the ability to destroy nearby structures by its power to cause bone resorption and as a result, fatal complications prevail. We aimed to conduct a comprehensive review for pathogenesis of acquired cholesteatoma, bone resorption mechanisms, and offer a future vision of this serious disease. We have reviewed different theories for pathogenesis of acquired cholesteatoma including the most relevant and updated ones with special emphasis on the mechanisms of bone resorption through Medline/PubMed research using the keywords 'aetiopathogenesis, bone resorption, acquired cholesteatoma, temporal bone, and cytokines.' In order to strengthen our study, we searched the reference lists of identified reviews. Cholesteatoma is a subject of debate among otolaryngologists since it was prescribed firstly. Over many decades, several theories were postulated for aetiopathogenesis of cholesteatoma with a tendency to follow more than one theory to explain the proper nature of that disease. Until now, the mechanism of bone resorption has yet to be more clarified. In the last century, a leap has occurred in the field of biomolecular cholesteatoma research which improved our knowledge about its pathophysiology and bone destructive mechanism. However, surgery is still the only available treatment. We conclude that discovery of new therapeutic choices for cholesteatoma other than surgery by the use of anti-growth, anti-proliferative, apoptotic agents as well as medications that antagonize osteoclastogenesis should be the main concern in the future clinical and experimental research work. Also, searching for predictors of the aggressiveness of cholesteatoma can affect the timing of intervention and prevent occurrence of complications.

Future opportunities in preventing ototoxicity: Caffeic acid phenethyl ester may be a candidate (Review)

Caffeic acid phenethyl ester (CAPE) is an important active component of propolis, which is derived from honeybee hives. It has received increasing attention in a variety of medical and pharmaceutical research, due to its anti‑oxidant, antiproliferative, anti‑inflammatory, antiviral and antifungal activity, in addition to its antineoplastic properties. Besides the use of CAPE as an antioxidant and anti‑inflammatory agent in a number of in vivo studies of ear disease, its beneficial effects have been reported in the treatment of cancer, arthritis, allergies, heart disease, diabetes, kidney disease, liver disease and neurological disease. CAPE influences a number of biochemical pathways, as well as several targets involved in ear diseases, in particular, in ototoxicity. The protective effects of CAPE in ototoxicity, which may be induced by a number factors, including lipopolysaccharides, hydrogen peroxide and streptomycin, are evaluated and discussed in the present review.

Toxic inner ear lesion following otitis media with effusion: a comparative CT-study regarding the morphology of the inner ear

Viral infections of the upper respiratory airways can lead to a delayed viral otitis media (VOM) caused by a diffusion of viruses/virus particles through the round window membrane and resulting in sensorineural hearing loss. The treatment of choice is immediate paracentesis, evacuation of all fluids from the middle ear cavity, and haemorrheological infusions. However, in some cases, persistent symptoms may be an indication for a surgical approach using mastoidectomy. In high-resolution computed tomography, an extended small-sized pneumatisation of the mastoid cells with complete shading was found in these non-responsive cases. Therefore, a direct means of inner ear affliction through weak parts of the labyrinthine bone may be hypothesised. Patients suffering from a toxic inner ear lesion (TIEL) following a common cold, treated over a 10-year period in a Tertiary Care Centre (N = 52, 57 ears), were identified and the morphological characteristics of the temporal bones of affected patients were examined by means of high-resolution computed tomography (hrCT). The findings were compared with a matched control group of 64 normal ears (CONT). Measurements included the grade of pneumatisation, distances within the temporal bones and Hounsfield units (HU) at defined anatomical structures. In the TIEL group, we found a small-sized pneumatisation in 79.4 % and a medium-sized pneumatisation in 10.9 %, thus differing from the CONT group and the literature data. Thickness of the bone wall of the lateral semicircular canal (LSC) and distances within the aditus ad antrum were significantly reduced in the TIEL group. HU's were markedly lower in the TIEL group at the precochlea, the LSC, and dorsolateral to the promentia of the LSC. There was a correlation between the HU's at the prominentia of the LSC and the hearing loss (p = 0.002). Persisting interosseous globuli, as described in 1897 by Paul Manasse, form an osseochondral network within the otic capsule and may be responsible for a direct means of toxic inner ear infection. The CT-morphometric results support this thesis. In the group of these patients (TIEL) a CT-scan and in non-responders to conservative treatment a surgical approach by mastoidectomy is recommended.

Mean platelet volume as an inflammatory marker of chronic otitis media with effusion

OBJECTIVES

Our aim was to investigate whether mean platelet volume (MPV) may be utilized as an inflammatory marker of chronic otitis media with effusion (COME).

METHODS

Routine hemogram tests were performed preoperatively for 51 patients diagnosed with COME that were to receive ventilation tube insertion. Hemogram tests were performed on age-matched and sex-matched healthy controls (n=54). Moreover, by performing a chart review, white blood cell count (WBC), red blood cell count (RBC), hemoglobin (Hb), hematocrit (Hct), platelet (PLT), and mean platelet volume (MPV) values were compared between COME patients and controls.

RESULTS

A total of 51 COME patients were included in the study and 45.1% were male. The control group had 54 individuals and 51.9% were male. MPV (p=0.493) and platelet levels (p=0.336) for COME patients group were generally borderline higher than those measured for the control group, but this difference was not statistically significant.

CONCLUSION

No statistically significant differences were identified between pediatric patients diagnosed with COME and healthy controls in terms of WBC, RBC, Hb, Hct, PLT and MPV levels.

Deletion of the complement C5a receptor alleviates the severity of acute pneumococcal otitis media following influenza A virus infection in mice

There is considerable evidence that influenza A virus (IAV) promotes adherence, colonization, and superinfection by S. pneumoniae (Spn) and contributes to the pathogenesis of otitis media (OM). The complement system is a critical innate immune defense against both pathogens. To assess the role of the complement system in the host defense and the pathogenesis of acute pneumococcal OM following IAV infection, we employed a well-established transtympanically-induced mouse model of acute pneumococcal OM. We found that antecedent IAV infection enhanced the severity of acute pneumococcal OM. Mice deficient in complement C1qa (C1qa^−/−) or factor B (Bf ^−/−) exhibited delayed viral and bacterial clearance from the middle ear and developed significant mucosal damage in the eustachian tube and middle ear. This indicates that both the classical and alternative complement pathways are critical for the oto-immune defense against acute pneumococcal OM following influenza infection. We also found that Spn increased complement activation following IAV infection. This was characterized by sustained increased levels of anaphylatoxins C3a and C5a in serum and middle ear lavage samples. In contrast, mice deficient in the complement C5a receptor (C5aR) demonstrated enhanced bacterial clearance and reduced severity of OM. Our data support the concept that C5a-C5aR interactions play a significant role in the pathogenesis of acute pneumococcal OM following IAV infection. It is possible that targeting the C5a-C5aR axis might prove useful in attenuating acute pneumococcal OM in patients with influenza infection.

Otitis media with effusion: an effort to understand and clarify the uncertainties

Otitis media with effusion--defined as the accumulation of middle-ear effusion behind an intact tympanic membrane without signs or symptoms of acute infection--is one of the most common causes of hearing loss in children in developed countries, potentially leading to language deficits. Although treatment of chronic or relapsing otitis media with effusion is considered imperative, none of the preventative or nonsurgical management measures currently available have proven effective. Tympanostomy tube placement remains the recommended treatment option for high-risk children or for cases of unresponsive otitis media with effusion. This can be attributed to the uncertainties surrounding its pathogenesis. Multiple factors and several possible pathogenetic models have been proposed to explain the production and persistence of middle-ear effusion; only a few of them are supported by sufficient evidence. In this review, the authors will present current knowledge on the pathogenesis, consequences, diagnosis and management of otitis media with effusion. An effort will be made to clarify those aspects sufficiently supported by evidence-based studies, and to underline those that remain unfounded.

Neutralizing antibody against granulocyte/macrophage colony-stimulating factor inhibits inflammatory response in experimental otitis media

OBJECTIVES/HYPOTHESIS

Granulocyte/macrophage colony-stimulating factor is important in the pathogenesis of acute and chronic inflammatory disease. We hypothesized that granulocyte/macrophage colony-stimulating factor plays a pivotal role in middle ear inflammation and that neutralization of granulocyte/macrophage colony-stimulating factor would inhibit neutrophil migration into the middle ear and production of inflammatory mediators.

STUDY DESIGN

Animal experiment.

METHODS

We used transtympanic administration of lipopolysaccharide, a major component of gram-negative bacteria, into mice to induce an experimental otitis media. Control mice received injection of phosphate-buffered saline into the middle ear cavity. Mice were systemically treated with granulocyte/macrophage colony-stimulating factor neutralizing antibody or control immunoglobulin G via intraperitoneal injection 2 hours before transtympanic injection of lipopolysaccharide or phosphate-buffered saline. Middle ear effusions were collected. Concentrations of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, keratinocyte chemoattractant, and macrophage inflammatory protein-2 in middle ear effusions were measured by enzyme-linked immunosorbent assay. Histologic examination of the middle ear was also performed.

RESULTS

Transtympanic injection of lipopolysaccharide upregulated levels of granulocyte/macrophage colony-stimulating factor, IL-1β, TNF-α, keratinocyte chemoattractant, and macrophage inflammatory protein-2 in the middle ear. Concentrations of cytokines and chemokines were significantly decreased in mice injected with granulocyte/macrophage colony-stimulating factor neutralizing antibody. Infiltration of inflammatory cells into the middle ear cavity induced by lipopolysaccharide was also significantly reduced by neutralization of granulocyte/macrophage colony-stimulating factor.

CONCLUSIONS

Systemic injection of granulocyte/macrophage colony-stimulating factor neutralizing antibody inhibits the middle ear inflammation induced by lipopolysaccharide in mice. Our findings suggest that granulocyte/macrophage colony-stimulating factor may offer a novel therapeutic target for the management of intractable otitis media.

Detection of soluble interleukin-2 receptor and soluble intercellular adhesion molecule-1 in the effusion of otitis media with effusion

We measured sIL-2R, TNF-alpha and sICAM-1 in the sera and middle ear effusions (MEEs) of patients with otitis media with effusion (OME). Although there was no signmcant difference between the sIL-2R levels of the serous and mucoid MEEs, they were significantly higher than serum sIL-2R levels of OME patients and healthy controls. TNF-alpha levels of the mucoid MEEs were significantly higher than those of the serous type. However, TNF-alpha was rarely detected in the sera of OME patients or healthy controls. We observed significant differences between the serous and mucoid MEEs with respect to their sICAM-1 levels, which were also higher than serum slCAM-1 levels of OME patients and healthy controls. Our findings suggested that IL-2, TNF-alpha and ICAM-1 could be significantly involved in the pathogenesis of OME through the cytokine network.

Novel rat model of tympanostomy tube otorrhea

OBJECTIVE

Tympanostomy tube otorrhea (TTO), caused by the presence of pathogenic bacteria in the middle ear, is the most common complication of TT insertion. No studies have described a reproducible animal model of TTO. We aimed to develop a rat model of TTO which, in turn, could be used to assay the levels of TNF-α and IL-1β through the course of the infection.

METHODS

The left Eustachian tubes of 55 male Sprague-Dawley albino rats were occluded with gutta-percha (ETO=Eustachian Tube Occlusion). Middle ear (ME) effusion was ascertained by weekly otomicroscopy. At 3 weeks tympanostomy tubes were placed bilaterally and the MEs were inoculated bilaterally with Streptococcus pneumoniae through the tubes. The rats were randomly assigned to one of two daily ototopical treatments: ciprofloxacin/dexamethasone (CDX) or placebo. The animals in each of the two treatment groups were further divided to receive 1, 2, 5 or 7 days of treatment. The rats were sacrificed after treatment was finished. The rates of otorrhea, positive middle ear (ME) cultures, and levels of TNF-α and IL-1β in the ME fluid were measured.

RESULTS

Left ETO followed by ME inoculation with S. pneumoniae and treatment with placebo resulted in persistent infection (100% culture-positive ME fluid at 10 days) and otorrhea (85.7%). Persistent infection of the left ear was accompanied by significantly elevated the levels of IL-1β and TNF-α. Ears treated with CDX had lower rates of otorrhea at all time points and lower levels of IL-1β and TNF-α.

CONCLUSIONS

This study is the first to describe a reproducible animal model of acute TTO. Surgical obstruction of the ET, followed by TT placement and ME inoculation with S. pneumoniae induced persistent otorrhea and infection. Both IL-1β and TNF-α appear to be potential markers of persistent middle ear infection. This novel model may be used in future studies of the pathogenesis and therapy of TTO.

Effect of Ginkgo leaf parenteral solution on blood and cochlea antioxidant and immunity indexes in OM rats

Oxidative stress is involved in the development and progression of otitis media (OM). In this study, we investigated the effect of Ginkgo leaf parenteral solution on blood and cochlea antioxidant and immunity indexs in OM rats. In OM model rats, blood and cochlea malondialdehyde (MDA), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and interleukin-10 (IL-10) levels were significantly increased, whereas antioxidant enzymes activities (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR)) were significantly decreased compared with normal rats. Treatment with Ginkgo leaf parenteral solution restored the altered parameters in a dose-dependent manner. We conclude that Ginkgo leaf parenteral solution confers protection against oxidative injuries in OM rats by increasing activities of antioxidants and immunity, suggesting a potential drug for the prevention and therapy of OM.

Guggulsterone suppresses LPS induced inflammation of human middle ear epithelial cells (HMEEC)

OBJECTIVE

Guggulsterone is a bioactive constituent of resinous sap originating from the guggul tree, Commiphora mukul, which has been used over several thousands of years to treat various diseases, including atherosclerosis, rheumatism, and obesity. However, the effect of guggulsterone inflammatory reactions induced by lipopolysaccharide (LSP) is not known. The aim of this study was to evaluate the anti-inflammatory effect of guggulsterone on cultured human middle ear epithelial cells (HMEEC).

METHODS

The effect of guggulsterone on LPS-induced tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) expression was evaluated in HMEEC by real-time reverse transcription polymerase chain reaction (RT-PCR). LPS-induced COX-2 production and degradation of the inhibitor kB-alpha (IkB-α) were determined by Western blot analysis.

RESULTS

Guggulsterone significantly inhibited LPS-induced upregulation of TNF-α and COX-2 in a dose-dependent manner. COX-2 protein production by LPS was significantly suppressed by the guggulsterone pretreatment. Furthermore, LPS-induced IkB-α degradation was suppressed by the guggulsterone pretreatment.

CONCLUSIONS

These results show that the guggulsterone has inhibitory effect on TNF-α expression and COX-2 production and it may be mediated through its inhibition of nuclear factor-kB activation. Our findings provide an insight into the molecular mechanisms underlying the anti-inflammatory activities of guggulsterone in relationship to otitis media.

Functional and molecular expression of epithelial sodium channels in cultured human endolymphatic sac epithelial cells

HYPOTHESIS

Epithelial sodium channels are expressed in cultured human endolymphatic sac (ES) epithelial (HESE) cells and epithelial sodium channel (ENaC) expression is suppressed by interleukin 1beta.

BACKGROUND

The ES is part of the membranous labyrinth in the inner ear that plays an important role in maintaining homeostasis of the endolymphatic fluid system. However, the exact mechanism of fluid volume regulation is not yet known.

METHODS

The ES specimens were harvested during acoustic neuroma surgery (n = 13) using the translabyrinthine approach and were subcultured with high-epidermal growth factor (25 ng/mL) media.

RESULTS

The serially passaged HESE cells differentiated into a monolayer of confluent cells and some of the cultured cells had features of mitochondria-rich cells. Reverse transcription-polymerase chain reaction revealed that ENaC subunits are expressed in the cultured HESE cells. We also confirmed the presence of an ENaC-dependent short-circuit current in the cultured HESE cells. Interestingly, ENaC mRNA expression and ENaC-dependent current decreased after treatment with interleukin 1beta (10 nmol/L for 24 h).

CONCLUSION

These findings suggest that ENaC plays an important role in fluid absorption in the human ES and that its function may be altered during inflammatory conditions.

Interferon-gamma in suppurative otitis media: significance of otorrhoea type and disease outcome

BACKGROUND

Interferon-gamma has been reported to have an immunoregulatory role in otitis media with effusion. However, such a role remains to be determined in acute suppurative otitis media.

AIM

To determine the levels of interferon-gamma in middle-ear secretion in children with acute suppurative otitis media, and to determine the significance of interferon-gamma to the nature of otorrhoea and the outcome of otitis media.

SETTINGS AND DESIGN

Prospective, longitudinal follow up of patients selected from community and tertiary health centres.

METHODS

We selected children with acute suppurative otitis media, diagnosed as otorrhoea of less than three months' duration. Middle-ear secretions were collected by pipetting and stored at -80 degrees C. Interferon-gamma was assayed using enzyme-linked immunosorbent assay. The patients were treated and followed up for nine to 12 months, to separate those with resolved acute suppurative otitis media from those with chronic suppurative otitis media.

RESULT

The study initially included 358 cases of acute suppurative otitis media. Nine-month follow up was achieved in 304 patients (85 percent). Of these patients, acute suppurative otitis media resolved in 187 (61 percent), while chronic suppurative otitis media was evident in 117 (39 percent). The children with completed follow up comprised 173 boys and 131 girls, aged between four months and nine years (mean age 6.6 years; standard deviation 1.32). These children had purulent otorrhoea in 171 cases (56 percent) and mucoid otorrhoea in 133 cases (44 percent). The children's middle-ear secretion interferon-gamma concentrations ranged from 12 to 126 pg/ml. The mean middle-ear secretion interferon-gamma concentration was 27.2 pg/ml (standard deviation 8.8) in patients whose acute suppurative otitis media resolved, and 73.1 pg/ml (standard deviation 9.5) in those progressing to chronic suppurative otitis media. In children with purulent otitis media, the mean middle-ear secretion interferon-gamma concentration was 43.5 pg/ml (standard deviation 15.6); in those with mucoid otitis media, it was 74.3 pg/ml (standard deviation 19.1). Univariate analysis revealed significant differences in middle-ear secretion interferon-gamma concentration, comparing resolved acute suppurative otitis media and chronic suppurative otitis media cases (p = 0.00), and comparing purulent and mucoid otitis media cases (p = 0.00). Pearson correlation testing revealed significant inverse correlation between interferon-gamma concentration and middle-ear secretion immunoglobulin G concentration (p = 0.01), immunoglobulin E concentration (p = 0.03) and immunoglobulin A concentration (p = 0.00).

CONCLUSION

A high concentration of interferon-gamma in middle-ear secretions promotes chronicity of suppurative otitis media. Further research in this area may lead to the development of agents which assist the control of suppurative otitis media chronicity.

Inhibitory effect of caffeic acid phenethyl ester (CAPE) on LPS-induced inflammation of human middle ear epithelial cells

CONCLUSIONS

The results suggest that the anti-inflammatory effect of caffeic acid phenethyl ester (CAPE) is due to its inhibition of tumor necrosis factor (TNF)-alpha expression and interleukin (IL)-8 production. The anti-inflammatory effect of CAPE is possibly through the inhibition of nuclear factor (NF)-kappaB via the suppression of inhibitor-kappaB-alpha (IkappaB-alpha) degradation.

OBJECTIVES

CAPE is a biologically active component of propolis, a resinous material obtained from bee hives, which originates from conifer bark. The effect of CAPE on lipopolysaccharide (LPS)-induced inflammatory reactions is not known. The aim of this study was to evaluate the anti-inflammatory effect of CAPE on cultured human middle ear epithelial cells (HMEECs).

MATERIALS AND METHODS

The effect of CAPE on LPS-induced TNF-alpha expression was evaluated in HMEECs by real-time reverse transcription polymerase chain reaction (RT-PCR). LPS-induced IL-8 production was determined by enzyme-linked immunosorbent assay (ELISA), and LPS-induced IkappaB-alpha degradation was followed by Western blot analysis.

RESULTS

CAPE significantly inhibited LPS-induced up-regulation of TNF-alpha in a dose-dependent manner. IL-8 production by LPS was significantly suppressed by the CAPE pretreatment. Furthermore, LPS-induced IkappaB-alpha degradation was suppressed by the CAPE pretreatment.

Preliminary study of proinflammatory cytokines and chemokines in the middle ear of acute otitis media due to Alloiococcus otitidis

Alloiococcus otitidis is a newly discovered organism frequently detected in otitis media. However, the association of the organism with the development of otitis media has not been disclosed in detail yet. In the middle ear, proinflammatory cytokines and chemokines are released in association with infection by pathogens, and these cytokines contribute to the induction of an inflammatory reaction. To investigate the profile of inflammation-related cytokines in the acute phase of A. otitidis infection, we analyzed the release of proinflammatory cytokines and chemokines in middle ear effusions of acute otitis media due to A. otitidis, in comparison with acute otitis media due to the well-known Gram-positive middle ear pathogen Streptococcus pneumoniae. The amounts of proinflammatory cytokines (IL-8, IL-1beta, IL-6, TNF-alpha) and CXC chemokines (IP-10, I-TAC) were significantly increased in the A. otitidis group as well as in the S. pneumoniae group. Various inflammation-related cytokines/chemokines were induced in the A. otitidis-infected middle ear, and the profile of cytokines was very similar to that in S. pneumoniae infection. This preliminary study suggests that A. otitidis has the potential to induce these cytokines, contributing to the development of an inflammatory reaction in the middle ear cavity in a similar manner to S. pneumoniae.

Role of nasal allergy in chronic secretory otitis media

Nasal allergy seems to be one of the important causes of chronic secretory otitis media (SOM) in children and adults. Chronic SOM is unequivocally related to disturbed function of the eustachian tube, which facilitates communication of the middle ear with the nasopharynx, nasal cavity, and indirectly with paranasal sinuses. The most serious consequences of chronic SOM are decreased elasticity of the tympanic membrane and hearing impairment. Allergic reactions in the nasal mucosa leading to release of various mediators result in development of three types of nasal response characterized predominantly by nasal obstruction. Eustachian tube functions can be affected directly by the mediators released in the nasal mucosa or indirectly by the nasal obstruction. Nasal challenges with allergens performed by rhinomanometry, combined with tympanometry and eventually audiometry, may be a useful diagnostic supplement for this disorder.

Gene expression differences in infected and noninfected middle ear complementary DNA libraries

OBJECTIVES

To investigate genetic differences in middle ear mucosa (MEM) with nontypeable Haemophilus influenzae (NTHi) infection. Genetic upregulation and downregulation occurs in MEM during otitis media (OM) pathogenesis. A comprehensive assessment of these genetic differences using the techniques of complementary DNA (cDNA) library creation has not been performed.

DESIGN

The cDNA libraries were constructed from NTHi-infected and noninfected chinchilla MEM. Random clones were picked, sequenced bidirectionally, and submitted to the National Center for Biotechnology Information (NCBI) Expressed Sequence Tags database, where they were assigned accession numbers. These numbers were used with the basic local alignment search tool (BLAST) to align clones against the nonredundant nucleotide database at NCBI.

RESULTS

Analysis with the Web-based statistical program FatiGO identified several biological processes with significant differences in numbers of represented genes. Processes involved in immune, stress, and wound responses were more prevalent in the NTHi-infected library. S100 calcium-binding protein A9 (S100A9); secretory leukoprotease inhibitor (SLPI); beta(2)-microglobulin (B2M); ferritin, heavy-chain polypeptide 1 (FTH1); and S100 calcium-binding protein A8 (S100A8) were expressed at significantly higher levels in the NTHi-infected library. Calcium-binding proteins S100A9 and S100A8 serve as markers for inflammation and have antibacterial effects. Secretory leukoprotease inhibitor is an antibacterial protein that inhibits stimuli-induced MUC1, MUC2, and MUC5AC production.

CONCLUSIONS

A number of genes demonstrate changes during the pathogenesis of OM, including SLPI, which has an impact on mucin gene expression; this expression is known to be an important regulator in OM. The techniques described herein provide a framework for future investigations to more thoroughly understand molecular changes in the middle ear, which will likely be important in developing new therapeutic and intervention strategies.

The role of inflammatory mediators in the pathogenesis of otitis media and sequelae

This review deals with the characteristics of various inflammatory mediators identified in the middle ear during otitis media and in cholesteatoma. The role of each inflammatory mediator in the pathogenesis of otitis media and cholesteatoma has been discussed. Further, the relation of each inflammatory mediator to the pathophysiology of the middle and inner ear along with its mechanisms of pathological change has been described. The mechanisms of hearing loss including sensorineural hearing loss (SNHL) as a sequela of otitis media are also discussed. The passage of inflammatory mediators through the round window membrane into the scala tympani is indicated. In an experimental animal model, an application of cytokines and lipopolysaccharide (LPS), a bacterial toxin, on the round window membrane induced sensorineural hearing loss as identified through auditory brainstem response threshold shifts. An increase in permeability of the blood-labyrinth barrier (BLB) was observed following application of these inflammatory mediators and LPS. The leakage of the blood components into the lateral wall of the cochlea through an increase in BLB permeability appears to be related to the sensorineural hearing loss by hindering K⁺ recycling through the lateral wall disrupting the ion homeostasis of the endolymph. Further studies on the roles of various inflammatory mediators and bacterial toxins in inducing the sensorineumral hearing loss in otitis media should be pursued.

Interleukin-10 is an essential modulator of mucoid metaplasia in a mouse otitis media model

OBJECTIVES

Inflammatory cytokines are involved in the development of mucous cell metaplasia and hyperplasia (MCM) in otitis media (OM). However, which cytokines play an essential role in the MCM of OM is not clear at the moment.

METHODS

In this study, we hypothesized that interleukin-10 (IL-10) played an indispensable role in the MCM of bacterial OM, and we used IL-10 knockout mice to test this hypothesis.

RESULTS

In wild-type mice, both Streptococcus pneumoniae and Haemophilus influenzae triggered the development of MCM in the middle ear mucosa. In IL-10 knockout mice, the number of goblet cells and mucin-producing cells in the middle ear was significantly reduced after bacterial middle ear infection compared with that in wild-type mice.

CONCLUSIONS

We conclude that IL-10 plays an essential role in the MCM of bacterial OM. Interleukin-10 is a potential target for the treatment of MCM in OM.

Comparison of cytokine levels in bilateral ear effusions in patients with otitis media secretoria

OBJECTIVE

The aim of this study was to clarify the site of primary pathology in otitis media with effusion.

STUDY DESIGN AND SETTING

The levels of the inflammatory mediators TNF-alpha, TNF-beta, IL-1beta, IL-8, IL-6, IL-4, IL-2, IL-5, IL-10, and IFN-gamma were measured in 54 pairs (108 samples) using specific enzyme-linked immunosorbent assays (ELISAs).

RESULTS

The levels of pro-inflammatory cytokines TNF-alpha, TNF-beta, IL-1beta, IL-8, anti-inflammatory cytokines IL-5, IL-4, IL-10, IL-6, and cytokines with immunoregulatory potential IFN-gamma, IL-2 were different between both ears of the same patient.

CONCLUSION

The results suggest that in one individual both ears have different immunological processes or rates and this has implications on using the opposite ear as a control in clinical trials.

SIGNIFICANCE

Profiles of interlink of examined cytokines within the samples of both ear effusions were significantly different. A significant bilateral difference was found in the levels of IFN-gamma.

Characterization of otitis media with effusion based on the ratio of albumin and immunoglobulin G concentrations in the effusion

OBJECTIVE

To characterize the groups of middle ear effusions (MEE) defined on the basis of the ratio of albumin and immunoglobulin G concentrations (A/G) in the effusion and to identify the correlation between these groups of MEE and the clinical features of otitis media with effusion (OME).

STUDY DESIGN

A laboratory analysis of 88 samples of MEE and a retrospective analysis of the medical history of all patients was performed.

SETTING

Tertiary referral center.

PATIENTS

Thirty-three girls and 23 boys with OME were included in the study.

INTERVENTION

The concentrations of albumin, immunoglobulins (IgG, IgA, and IgM), complement factors (C3, C4), and C-reactive protein were determined by means of nephelometry. Enzyme-linked immunosorbent assay was used to measure cytokines interferon-gamma, tumor necrosis factor alpha, interleukin (IL)-4, and IL-10 concentrations. Groups were defined according to A/G ratio in the effusions. Thirty-five children underwent allergy testing.

MAIN OUTCOME MEASURE

Two groups of MEE could be recognized on the basis of A/G ratio; the ratio was lower than 0.7 in group A and was higher than 0.7 in group B.

RESULTS

Increased levels of interferon-gamma and tumor necrosis factor alpha were observed in group A, whereas IL-4 and IL-10 were dominating in group B. No association was found between the MEE groups and the clinical features of the disease or the atopic status of the patient.

CONCLUSION

These results suggest that various groups of OME can be categorized according to the differences in A/G ratio in the effusions. These differences can reflect the variances in the pathomechanism of the development of the effusion, the stage of the disease, or the clinical background of the patients.

Interleukin-1beta upregulates Na+-K+-2Cl- cotransporter in human middle ear epithelia

Disruption of periciliary fluid homeostasis is the main pathogenesis of otitis media with effusion (OME), one of the most common childhood diseases. Although the underlying molecular mechanisms are unclear, it has been suggested that the altered functions of ion channels and transporters are involved in the fluid collection of middle ear cavity of OME patients. In the present study, we analyzed the effects of a major cytokine interleukin (IL)-1beta, which was known to be involved in the pathogenesis of OME, on Na(+)-K(+)-2Cl(-) cotransporter (NKCC) in human middle ear cells. Intracellular pH (pH(i)) was measured in primary cultures of normal human middle ear epithelial (NHMEE) cells using a double perfusion chamber, which enabled us to analyze the membrane-specific transporter activities. NKCC activities were estimated by the pH(i) reduction due to bumetanide-sensitive intracellular uptake of NH(4) (+). In NHMEE cells, NKCC activities were observed only in the basolateral membrane, and immunoblotting using specific antibodies revealed the expression of NKCC1. Interestingly, IL-1beta treatments augmented the basolateral NKCC activities and increased NKCC1 expression. In addition, IL-1beta treatments stimulated bumetanide-sensitive fluid transport across the NHMEE cell monolayers. Furthermore, an elevated NKCC1 expression was observed in middle ear cells from OME patients when compared to those from control individuals. The above results provide in vitro and in vivo evidence that the inflammatory cytokine IL-1beta upregulates NKCC1 in middle ear epithelial cells, which would be one of the important underlying mechanisms of excess fluid collection in OME patients.

Interleukin-1β suppresses epithelial sodium channel β-subunit expression and ENaC-dependent fluid absorption in human middle ear epithelial cells

Recent reports have shown that cytokines inhibit fluid absorption by suppressing Na(+) channel activity in various epithelia. In this study, we investigated the role of epithelial sodium channel (ENaC) in fluid absorption in normal human middle ear epithelial (NHMEE) cells, as well as the effects of Interleukin (IL)-1beta on ENaC expression and fluid absorption in NHMEE cells. We confirmed that ENaC alpha, beta and gamma were predominantly expressed on the apical surface of the NHMEE cells by immunocytochemistry. Addition of amiloride, a potent ENaC blocker, to apical membranes of NHMEE cells decreased the fluid absorption rate in a dose-dependent manner. Treatment with 10 ng/ml IL-1beta for 24 h suppressed ENaC beta expression, the ENaC-dependent short-circuit current (Isc), and ENaC-dependent fluid absorption. When the NHMEE cells were pretreated with a phospholipase C (PLC)inhibitor (U73122, 10 microM), a protein kinase C (PKC) inhibitor (Calphostin C, 0.1 microM), or extracellular signal regulated kinase (ERK) 1/2 inhibitor (PD98059, 10 microM), the amiloride-sensitive currents in IL-1beta-treated cells were reversed to control levels; an effect not seen with SB202190 (an inhibitor of p38 mitogen-activated protein (MAP) kinase) or SP600125 (a reversible inhibitor of c-Jun N-terminal kinase). In this study we showed that ENaC is essential for fluid absorption in NHMEE cells and that IL-1beta suppresses the ENaC-dependent current via the PLC-PKC-ERK1/2 pathway. These results suggest that IL-1beta may contribute to fluid retention in otitis media with effusion by changing electrolyte transport and reducing middle ear epithelial fluid absorption.

Clinical and biochemical factors that affect DPOAE expressions in children with middle ear effusion

OBJECTIVES

To evaluate the clinical and biochemical characteristics of middle ear effusion (MEE) that affect distortion product otoacoustic emissions (DPOAE) responsiveness and to investigate the possible role of DPOAE as a tool to know the characteristics of MEE preoperatively.

STUDY DESIGN AND SETTING

Prospective analysis of children with MEE effusion in a tertiary referral center. DPOAE results were compared with other audiologic tests, the character, amount of MEE, the amount of total protein, and TNF-alpha in the effusion.

RESULTS

The negative DPOAE with MEE group had much more thick mucous fluid in their middle ears than that of positive DPOAE with MEE group. The levels of total protein and TNF-alpha in MEE were significantly higher in the negative DPOAE group than those of the positive DPOAE group (P < 0.01).

CONCLUSIONS AND SIGNIFICANCE

The measurement of DPOAE in the children with MEE may predict the amount and the characteristics of MEE, which may help to decide the treatment methods.

Effect of inhibitor of tumor necrosis factor-alpha and oxatomide on immune mediated otitis media

OBJECTIVE

Inflammatory mediators (IMs) play a major role in the production of middle ear effusion (MEE). Tumor necrosis factor (TNF)-alpha and leukotrienes (LTs) appear to be important in the pathogenesis of otitis media with effusion (OME). The purpose of this study is to determine the effect of TNF-alpha and LT antagonist on the outcome of experimental immune-mediated OME.

STUDY DESIGN

Prospective.

METHODS

Otitis media was induced in rats by injecting keyhole limpet hemocyanin (KLH) transtympanically 7 days after systemic immunization. Experimental groups were treated with soluble TNF receptor type I (sTNF RI) or oxatomide simultaneously. Seventy-two hours after transtympanic injection, MEE was aspirated, and temporal bone was taken. Vascular permeability (VP) of the middle ear mucosa was measured using the Evans blue dye technique. Hematoxylin-eosin stain and immunohistochemical stain for leukocyte common antigen was performed.

RESULTS

In KLH, sTNF RI, and oxatomide groups, MEE was developed in 83%, 0%, and 66% of the ears, respectively. The sTNF RI group showed significant decrease in effusion production, inflammation, mucosal thickening, and VP compared with the KLH group. These parameters were less significant in the oxatomide group than in the sTNF RI group.

CONCLUSION

Transtympanic administration of sTNF RI and oxatomide appears to suppress the development of immune-mediated MEE.

Effects of tumor necrosis factor alpha antagonist, platelet activating factor antagonist, and nitric oxide synthase inhibitor on experimental otitis media with effusion

OBJECTIVES

We studied the inflammatory responses in otitis media with effusion induced by lipopolysaccharide (LPS) in rats, and compared the preventive effects of tumor necrosis factor (TNF) soluble receptor type I (sTNFRI, a TNF-alpha antagonist), platelet activating factor antagonist, and the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME).

METHODS

We used 2 control groups of Sprague Dawley rats (untreated and saline-treated) and 4 experimental groups, which all received an intratympanic injection of LPS, followed in 3 groups by experimental treatment of the same ear. The LPS group had no additional treatment. The L-NAME group received intraperitoneal injection of L-NAME and was reinjected after 12 hours. The A-85783 group was first given an intraperitoneal injection of A-85783. The sTNFRI group was first given an intratympanic injection of sTNFRI. Twenty-four hours after the initial intratympanic injection of LPS, temporal bones from each group were examined histopathologically and the vascular permeability of the middle ear mucosa was measured by Evans blue vital dye staining.

RESULTS

The L-NAME, A-85783, and sTNFRI groups showed significantly reduced capillary permeability, subepithelial edema, and infiltration of inflammatory cells in comparison with the LPS group. There were no differences in capillary permeability, subepithelial edema, or infiltration of inflammatory cells between the A-85783 and sTNFRI groups. The L-NAME group showed no difference in vascular permeability or subepithelial edema in comparison with the A-85783 and sTNFRI groups, but showed more infiltration of inflammatory cells.

CONCLUSIONS

We conclude that sTNFRI, A-85783, and L-NAME can be proposed as alternative future treatments for otitis media with effusion. However, L-NAME may be the least effective of these agents.

Analysis of risk factors for childhood persistent middle ear effusion

Although exposure to infectious agents and parental smoking are known to influence the overall risk of otitis media, these risk factors do not appear to be linked with the tendency to develop chronic otitis media with effusion (COME) instead of recurrent acute otitis media (RAOM). The genetic inflammatory response type of the child appears to influence the risk of persistent middle ear effusion in COME. Two different clinical presentations of childhood otitis media are encountered: RAOM; and COME, which is associated with persistent effusion in the middle ear. The objective of this study was to assess putative factors that may regulate the development of persistent middle ear effusion in COME. In total, 159 children with RAOM and their parents (n=304), and 55 children with COME and their parents (n=110) were evaluated. All the children with COME or RAOM were aged <4 years. There was no difference in the frequency of attendance at day care outside the home, number of siblings or parental smoking between children with RAOM and those with COME. The frequency of parental allergy and asthma was lower among children with COME than those with RAOM.

Evidence of T-helper cell 2 cytokine regulation of chronic otitis media with effusion

Cytokine and cellular patterns of effusions may reflect stages of middle ear inflammation. The local interplay between IL-2 and -4 is likely to play a crucial role in the switching of inflammation in the chronic stage. The T-helper cell 2 (Th2) cytokines IL-4, -5 and -13 and the Th2/Th1 cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) regulate the cellular and molecular processes of chronic inflammation in the middle ear and therefore the chronic condition of otitis media with effusion (OME). Early identification of the cytokine and cellular patterns of effusions can be helpful in directing the clinical treatment of OME.We hypothesized that IL-2 and the group of Th2 cytokines regulate chronic inflammation in the middle ear and chronic OME. Effusions from children with persistent OME were analysed to determine the presence of cytokines (the Th1 cytokine IL-2, the Th2 cytokines IL-4, -5 and -13 and the Th1/Th2 cytokine GM-CSF), inflammatory cells (CD4+ T cells, eosinophils, macrophages and neutrophils) and mucin. Cytokines were evaluated by means of a quantitative "sandwich"-type ELISA, inflammatory cells by means of alkaline phosphatase-anti-alkaline phosphatase immunocytostaining and mucin by means of a modified periodic acid-Schiff method based on a slot-blot technique. The cytokine pattern in effusions varied from patient to patient. GM-CSF correlated positively and IL-4 inversely with IL-2 and the increased level of IL-4 may have had an inhibitory effect on IL-2. IL-5 and -13 correlated with IL-4. Inflammatory cells correlated with cytokines as follows: CD4+ T cells with IL-2 and -4; macrophages and neutrophils with GM-CSF; and eosinophils with IL-5. Some cytokine-cellular correlations in effusions were reflected at the clinical level. The mucin content of effusions correlated with the concentrations of IL-4 (>10 pg/ml) and -13, suggesting involvement of IL-4 and -13 in upregulation of the middle ear mucin metabolism.

A new experimental model of acquired cholesteatoma

OBJECTIVE

Cholesteatoma is a recurrent disease that is difficult control by otologists. This study aims to develop an experimental model of cholesteatoma that is easy to reproduce, using latex to induce the inflammatory reaction and propylene glycol as the foreign body in the middle ear.

STUDY DESIGN

We used a new experimental model in which an intentional perforation was performed on the tympanic membrane of rats, followed by the introduction of a latex biomembrane.

METHODS

A control group was submitted only to perforation of the tympanic membrane. Propylene glycol with latex was used in experimental group 1 and latex alone in experimental group 2. The rats were killed during the eighth week and their tympanic bullae were stained with hematoxylin and eosin.

RESULTS

Eighty percent of the animals in group 1 and 90% in group 2 developed a cholesteatoma. No formation of cholesteatomas or inflammatory tissue occurred in the control group.

CONCLUSION

The presence of inflammatory cells may provoke the production of cytokines (IL-1, IL-2, IL-6, IL-8) and growth factors, which, together with the latex biomembrane, which is known to contain a protein that favors vascular growth, may cause chemotactic migration of the squamous epithelium from the external auditory meatus to the middle year of the rat, causing a cholesteatoma. The induction of an experimental cholesteatoma in rats with latex and latex plus 50% propylene glycol was effective, representing an excellent experimental model. The theory of epithelial migration in the genesis of cholesteatomas was confirmed by our observations in rats. The latex induced an acute and chronic inflammatory reaction when in contact with the mucosa of the middle ear.

The immunoregulatory and allergy-associated cytokines in the aetiology of the otitis media with effusion

Inflammation in the middle ear mucosa, which can be provoked by different primary factors such as bacterial and viral infection, local allergic reactions and reflux, is the crucial event in the pathogenesis of otitis media with effusion (OME). Unresolved acute inflammatory responses or defective immunoregulation of middle inflammation can promote chronic inflammatory processes and stimulate the chronic condition of OME. Cytokines are the central molecular regulators of middle ear inflammation and can switch the acute phase of inflammation in the chronic stage and induce molecular-pathological processes leading to the histopathological changes accompanying OME. In this review we present cytokines identified in otitis media, immunoregulatory [interleukin (IL)-2, IL-10, transforming growth factor-beta]) and allergy associated (IL-4, IL-5, granulocyte-macrophage colony-stimulating factor), as crucial molecular regulators, responsible for chronic inflammation in the middle ear and the chronic condition of OME.

IL-1beta promotes the ciliogenesis of human middle ear epithelial cells: possible linkage with the expression of mucin gene 8

CONCLUSIONS

These findings suggest that IL-1beta, increases ciliogenesis in NHMEE cells and that MUC8 protein may play a role in this process.

OBJECTIVES

The morphology of the middle ear epithelium changes under various pathologic conditions. We compared the density of ciliated cells and the level of mucin gene 8 (MUC8) mRNA in the middle ear epithelial cells of mucoid otitis media (MOM) patients with those of normal controls. We also investigated the effect of IL-1beta on the ciliogenesis and expression of MUC8 mRNA in cultured normal human middle ear epithelial (NHMEE) cells. In addition, we localized the MUC8 protein in cultured NHMEE cells.

MATERIAL AND METHODS

The surface morphology of NHMEE cells was examined using scanning electron microscopy. Reverse transcriptase polymerase chain reaction was performed to determine the level of MUC8 mRNA expression. After synthesis of MUC8 polyclonal antibody, we performed immunohistochemical staining.

RESULTS

The density of ciliated cells was increased in the middle ear epithelium of both MOM patients and IL-1beta-treated cultures. Similarly, the expression of MUC8 was increased in both cases. MUC8 antibody was primarily stained on the ciliated cells of NHMEE cells.

Middle ear epithelial mucin production in response to interleukin-6 exposure in vitro

OBJECTIVES

To investigate the role of the inflammatory cytokine interleukin-6 (IL-6) in the regulation of mucin secretion by middle ear epithelia.

MATERIALS AND METHODS

Primary chinchilla middle ear epithelial cultures were established and exposed to IL-6 in a dose- and time-dependent manner. Mucin secretion was characterized by exclusion chromatography and liquid scintillation.

RESULTS

Epithelial cultures exposed to increasing doses of IL-6 demonstrated greater amounts of mucin secretion (p=0.018). Additionally, cultures exposed to IL-6 at 50 ng/ml showed significant increased secretion of mucin over control in time-dependent experiments at 6-, 15- and 24-h time points (p=0.003).

CONCLUSIONS

IL-6 upregulates mucin secretion from cultured middle ear epithelial cells in a dose- and time-dependent manner. Elucidating the effect of specific cytokines on the regulation of mucin secretion is vital to understanding the pathophysiology of otitis media and the development of novel therapeutic strategies.

Cytokine Expression in Experimental Chronic Otitis Media With Effusion in Mice

OBJECTIVES

Although otitis media with effusion (OME) is still a common disease in children and adults, the pathogenesis is not yet fully understood. We studied the effects of intratympanic injection with endotoxin purified from nontypeable Haemophilus influenzae on the characteristics of middle ear effusion (MEE).

METHODS

Murine model of OME was developed by eustachian tube (ET) blockage followed by intratympanic inoculation with endotoxin (endotoxin group) or saline (control group). The mice were decapitated and histological changes and the production of inflammatory cytokines in MEEs were examined 3 days, 2 weeks, and 2 months after injection.

RESULTS

All mice showed OME until 2 months after ET blockage. Most MEEs in the control group were serous, and mucoid or pultaceous MEEs were found only in the endotoxin group. Subepithelial space of middle ear mucosa was severely thickened with the infiltration of a large number of mononuclear cells in the endotoxin group. The levels of tumor necrosis factor-alpha (TNF-alpha) in MEEs were significantly higher in the endotoxin group than in the control group at all time points. Further, in situ hybridization showed that TNF-alpha messenger RNA was expressed not only by leukocytes and macrophages in MEEs but mononuclear cells present in the subepithelial space of middle ear mucosa.

CONCLUSIONS

These results indicate that ET blockage is essential for the induction of serous MEE and additional administration of endotoxin is associated with the production of mucoid MEE accompanied by histological changes with inflammatory cell infiltration and cytokine production in the tympanic cavity.

Cell adhesion molecules and cytokines in middle ear effusions in children with or without recent acute otitis media

OBJECTIVES

We sought to compare the levels of cytokines and cell adhesion molecules in middle ear effusions (MEEs) of children with (group 1) or without (group 2) acute otitis media (AOM) within 3 months of obtaining MEE and to correlate these levels with hearing loss.

DESIGN AND SUBJECTS

MEE were collected from children (49 and 51 children composed groups 1 and 2, respectively) with otitis media with effusion (OME) undergoing tube placement who had an audiogram performed preoperatively. MEE was assessed as serous or mucoid. Cytokines and cell adhesion molecules were measured by enzyme-linked immunosorbent assay. Data were analyzed with the Student t test, chi(2) test, and the Pearson correlation test.

RESULTS

Concentrations of interleukin (IL)-1, IL-6, and vascular cell adhesion molecules (VCAM) were greater in the MEE of the children in group 1 compared with those of group 2 children. (P < 0.001 for IL-1 and IL-6; P < 0.05 for VCAM). The concentrations of IL-1, IL-6, VCAM, and E-selectin were greater in serous than in mucoid MEE. (P < 0.05). Concentrations of IL-6 correlated with the concentrations of the other 2 cytokines and the 3 cell adhesion molecules. Only concentrations of IL-6 in MEE correlated with the degree of hearing loss (P < 0.002).

CONCLUSIONS

The inflammatory response leading to OME involves multiple cytokines regardless of an AOM episode in the 3 months before obtaining MEE. IL-6 is an important cytokine in the pathogenesis of OME.