Expression of acute otitis media after receptor blockade of platelet activating factor, thromboxane, and leukotrienes in the chinchilla

The effect of the leukotriene antagonist pranlukast on pediatric acute otitis media

OBJECTIVE

Conventional treatment for acute otitis media mainly targets bacteria with antibiotics, neglecting to control for mediators of inflammation. Mediators of inflammation, such as leukotrienes, have been identified in patients with acute otitis media (AOM) or subsequent secretory otitis media (SOM). They can cause functional eustachian tube dysfunction or increase mucous in the middle ear, causing persistent SOM following AOM. The objective of the present study was to evaluate whether or not administration of pranlukast, a widely used leukotriene C4, D4, and E4 antagonist, together with antibiotics could inhibit the progression to SOM.

METHODS

Children with AOM, who were from two to 12 years old, were randomly divided into two groups as follows: a control group in which 50 patients received antibiotic-based conventional treatment according to guidelines for treating AOM proposed by the Japan Otological Society (version 2006); and a pranlukast group, in which 52 patients were administered pranlukast for up to 28 days as well as given conventional treatment. Cases were regarded as persistent SOM when a tympanogram was type B or C2 four weeks after treatment was initiated.

RESULTS

Two patients in the pranlukast group and 3 patients in the control group were excluded because they relapsed AOM within 28 days after initial treatment. Therefore, the analysis included 50 and 47 subjects in the pranlukast and control groups, respectively. The percentage of patients diagnosed with persistent SOM (22.0%) was significantly smaller in the pranlukast group compared with the control group (44.7%) (p = 0.018, chi-squared test).

CONCLUSION

The results indicate that combined treatment of AOM with antibiotics and a leukotriene antagonist to control inflammation is useful for preventing progression to persistent SOM.

Autosomal dominant progressive sensorineural hearing loss due to a novel mutation in the KCNQ4 gene

OBJECTIVE

To identify the genetic etiology in a family with autosomal dominant progressive sensorineural hearing loss.

DESIGN

Prospective molecular genetic research study.

SETTING

Academic genetic research laboratory.

PARTICIPANTS

Seventeen members of a family with dominant progressive nonsyndromic sensorineural hearing loss: 9 affected, 6 unaffected, and 2 spouses.

INTERVENTIONS

Clinical data from questionnaires, interviews, serial audiograms, and medical records; genetic data from genome-wide linkage analysis and candidate gene mutation analysis.

MAIN OUTCOME MEASURES

Symptoms, age at onset, serial audiometric data, and the presence or absence of a deafness-associated mutation.

RESULTS

Affected individuals in this family presented with autosomal dominant nonsyndromic high-frequency progressive sensorineural hearing loss, with age at onset ranging from 1 to 21 years. Genome-wide linkage analysis of single-nucleotide polymorphisms yielded evidence of linkage to an 18.9-Mb region on chromosome 1p34-p36, with a multipoint logarithm of odds score of 3.6. This interval contains a known deafness gene, KCNQ4, which underlies DNFA2 deafness. Sequencing of the 14 coding exons and intron-exon junctions of KCNQ4 revealed a novel heterozygous missense mutation, c.859G>C, p.Gly287Arg. The mutation disrupts the highly conserved GYG motif (glycine-tyrosine-glycine) of the phosphate-binding loop, hypothesized to be critical in maintaining pore structure and function. All 274 controls were negative for the mutation.

CONCLUSIONS

Autosomal dominant high-frequency hearing loss is genetically heterogeneous, and linkage analysis is an efficient means of identifying the etiology in larger families. Deafness in this family is caused by a novel mutation in KCNQ4.

Studies in otitis media: Children's Hospital of Pittsburgh-University of Pittsburgh progress report--2004

OBJECTIVES/HYPOTHESIS

The present Progress Report has summarized the key otitis media clinical trials and laboratory studies conducted since 1969 by investigators at the Children's Hospital of Pittsburgh-University of Pittsburgh (Pittsburgh, PA).

STUDY DESIGN

Review.

METHODS

Included in the discussion are the following: 1) studies of the epidemiology and risk factors; 2) anatomy and pathology of the eustachian tube-middle ear from human temporal bone histopathological specimens; 3) physiology and pathophysiology of the eustachian tube-middle ear in humans and animal models; 4) pathogenesis; 5) otitis media in special populations (e.g., patients with cleft palate, Native Americans, patients with Down syndrome); 6) microbiology; 7) diagnosis; 8) outcomes of randomized clinical trials that evaluated efficacy of nonsurgical and surgical methods of treatment and prevention; 9) studies of certain complications and sequelae (e.g., effect of middle-ear effusion on hearing, early child development, and the vestibular system; chronic suppurative otitis media). Also included are relevant summary tables and 256 references.

Cytokine profiles in a rat model of otitis media with effusion caused by eustachian tube obstruction with and without Streptococcus pneumoniae infection

OBJECTIVE

Cytokine expression was studied in a rat model of otitis media with effusion.

METHODS

The left eustachian tube was obstructed (eustachian tube obstruction [ETO]) in 84 rats. Forty-two ears were challenged with, and those rats were treated from day 2 to day 7 with ampicillin. Twelve rats (6 per group) were killed on days 1, 2, 7, 21, 35, 56, and 112; mucosa was harvested and assayed for interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), monocyte chemoattractant protein-1 (MCP-1), and interleukin-8 (IL-8) gene expression, and effusion was assayed for IL-1beta, TNF-alpha, IL-6, IL-10, and macrophage inflammatory protein-2 (MIP-2) protein.

RESULTS

Most cytokines were detectable in the effusion from infected ears with ETO on days 1 and 2 only. MIP-2 exhibited a biphasic response. Only effusion MIP-2 was consistently detected in uninfected ears with ETO. Three patterns of mucosal cytokine messenger RNA (mRNA) upregulation were observed: isolated early (IL-1beta, IL-8), isolated late (TNF-alpha, IFN-gamma), and biphasic (MCP-1, IL-6, TGF-beta) responses. Early cytokine mRNA upregulations were observed only in the infected ears with ETO, whereas late upregulations were observed in both groups.

CONCLUSIONS

Early expression of the assayed cytokines occurred only in ears with active infection. For both groups, a late upregulation of cytokine message but not protein was documented. The profile of cytokine expression during otitis media episodes may be useful in defining etiology, disease stage, and prognosis.

Effect of 10 pharmacologic probes on mRNA levels of inducible nitric oxide synthetase and selected inflammatory cytokines in a rat model of acute otitis media

Ten drugs were screened for their ability to decrease inflammatory mediator (IL-6, inducible nitric oxide synthetase [iNOS], IL-1beta and monocyte chemotactic protein [MCP-1]) expression in a rat model of acute otitis media caused by Streptococcus pneumoniae. Six adult rats were randomly assigned to each of 12 groups corresponding to uninfected controls and treatments with saline, aminoguanidine, anisomycin, dexamethasone, ketorolac, L-N(G)-nitroarginine methylester, methylprednisolone, mycophenolic acid, pentoxiphylline, tacrolimus or WEB2086. Forty-eight h after the start of treatment, the ears of the animals in the 11 treatment groups were challenged with S. pneumoniae. Forty-eight h later, all animals were killed and middle ear mucosa was harvested and assayed for RNA message. Messages for IL-6, iNOS and MCP-1 were significantly increased as a result of infection. Most treatments decreased MCP-1 and four decreased IL-6 and iNOS. Tacrolimus and dexamethasone decreased IL-6, iNOS and MCP-1. These results show that pharmacological agents can modify the expression of inflammatory mediators in this model and may have clinically relevant effects.

Effect of inhibitor of tumor necrosis factor-alpha on experimental otitis media with effusion

Tumor necrosis factor (TNF)-alpha is important in the pathogenesis of otitis media with effusion (OME). The purpose of this study was to determine the effect of TNF-alpha antagonist on the outcome of lipopolysaccharide (LPS)-induced OME in rats. Otitis media was induced by injecting Pseudomonas aeruginosa LPS transtympanically. Another (combination) group was pretreated with TNF-alpha antagonist, soluble TNF receptor type I (sTNF RI), before transtympanic injection of LPS. Saline and phosphate-buffered saline solutions were used as controls. Twelve hours after the transtympanic injection, otoscopic examination and aspiration of middle ear effusion (MEE) were done. The temporal bones in each group were examined histopathologically, and the vascular permeability of the middle ear mucosa was measured by the Evans blue vital dye technique. In the LPS and combination groups, MEE developed in 90% and 0% of ears, respectively. The combination group showed less inflammation, less mucosal thickening, and significantly decreased vascular permeability as compared to the LPS group. Transtympanic administration of sTNF RI appears to suppress the development of LPS-induced OME. This study suggests that TNF-alpha antagonist, along with antibiotics, may have an adjunctive role in the future treatment of MEE.

Upregulation of messenger RNA for inflammatory cytokines in middle ear mucosa in a rat model of acute otitis media

A rat model for acute otitis media has been established and was used to delineate the temporal expression of messenger RNA for key inflammatory cytokines. Inoculation with live Streptococcus pneumoniae induced a rapid expression of tumor necrosis factor alpha (within 6 hours) followed by upregulation of message for interleukin (IL)-6 (peak at 12 to 24 hours, remaining elevated through 120 hours) and IL-10 (peak at 24 hours). Inducible nitric oxide synthase message was also selectively increased following live bacterial inoculation (peak at 12 to 24 hours). Although there was a detectable inflammatory response to killed bacteria, it was minimal, was of short duration, and preceded the peak for live bacteria; only expression of IL-6 was significantly increased in this group (peak at 12 hours, remaining elevated through 72 hours). We interpret this to be due to an inflammatory response to bacterial products (such as lipopolysaccharide) in the heat-killed bacterial inoculum. The phosphate-buffered saline (PBS)-inoculated group exhibited a transient increase of IL-6 message, which indicates that this cytokine is a sensitive marker of the acute response to trauma. Otherwise, PBS invoked only a slight reaction in the mucosa with respect to the other inflammatory mediators being measured.