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

Mutation in Fbxo11 Leads to Altered Immune Cell Content in Jeff Mouse Model of Otitis Media

The Jeff mouse mutant carries a mutation in the F-box only 11 gene (Fbxo11) and heterozygous animals display conductive deafness due to the development of otitis media (OM). The Fbxo11 locus is also associated with chronic otitis media with effusion (COME) and recurrent OM in humans. The Jeff mutation affects the ability of FBXO11 to stabilize p53 that leads to perturbation in the TGF-beta/Smad2 signaling pathway important in immunity and inflammation. In the current study, we evaluated the effect of the Jeff mutation on the immune cell content using multicolor flow cytometry. In blood of Jeff heterozygotes, we observed a significant increase in the number of NK, dendritic (CD11b+), neutrophils, and natural killer T (NKT) cells and a significant decrease in effector T-helper and B-lymphocytes compared to wild-type controls. The percentage of NK cells significantly decreased in the lungs of Jeff heterozygotes, with a concomitant reduction in B-lymphocytes and T-cytotoxic cells. In the spleen, Jeff heterozygotes displayed a significant decrease in mature B-lymphocytes, effector T-helper, and naïve T-cytotoxic cells. Neutrophils, dendritic, and NKT cells dominated bulla fluid in Jeff heterozygote mice. Similar analysis carried out on Fbxo11^tm2b/+ heterozygotes, which carry a null allele, showed no difference when compared to wild-type. Cytokine/chemokine analysis revealed a significant increase in the G-CSF, GM-CSF, sTNFRI, TPO, and IL-7 levels in Jeff heterozygote serum compared to wild-type. This analysis increases our understanding of the role played by Fbxo11, a gene associated with human OM, in the systemic and localized cellular immune response associated with increased susceptibility to OM.

Innate signaling in otitis media: pathogenesis and recovery

Otitis media (OM) is the most prevalent childhood disease in developed countries. Involvement of innate immunity mediated by Toll-like receptors (TLRs) in OM has been implicated primarily in cell lines and by association studies of innate immune gene polymorphisms with OM prevalence. However, the precise role of innate immunity in OM is incompletely understood. We review recent research that has advanced our understanding of how innate immunity in the middle ear is mediated by the interaction of pathogen molecules with receptors such as the TLRs, leading to the activation of adaptor molecules and production of proinflammatory cytokines. TLR genes and signaling molecules are upregulated in OM in a murine model. Deletion of several key innate immune genes results in persistent OM in mice, coupled with an inability to clear bacterial infection from the middle ear. It is concluded that an intact innate immune signaling system is critical to recovery from bacterial OM.

CC chemokine ligand 3 overcomes the bacteriocidal and phagocytic defect of macrophages and hastens recovery from experimental otitis media in TNF-/- mice

Innate immune mechanisms are crucial in defense against bacterial illnesses in humans, as evidenced by abnormal antibacterial responses due to defects in TLR signaling, seen in children with MyD88 or IL-1R-associated kinase 4 deficiency. Otitis media (OM) is the most common disease of childhood, and the role of innate immune molecules in this disorder remains unclear. In a murine model of OM, we show that, in the absence of TNF, a key effector of innate immunity, this disease is prolonged after middle ear infection with nontypeable Haemophilus influenzae (NTHi). In the absence of TNF, mice fail to upregulate both TLRs and downstream genes and proteins, such as CCL3, resulting in defects in both inflammatory cell recruitment and macrophage function. Peritoneal macrophages of mice lacking TNF have a diminished ability to phagocytose and kill NTHi, and this defect is partially corrected in vitro by exogenous rTNF. Addition of rCCL3 alone or in combination with rTNF restores phagocytosis and killing by TNF-deficient macrophages to that of unstimulated wild-type macrophages. In vivo administration of rCCL3 to animals deficient in TNF fully restores the ability to control OM due to NTHi, whereas a CCL3-blocking Ab impaired the ability of wild-type mice to recover from OM. Thus, CCL3 is a potent downstream effector of TNF-mediated inflammation in vitro and in vivo. Manipulation of CCL3 and/or TNF may prove to be effective therapeutic approaches in OM or other conditions associated with defective TNF generation.

Effect of infliximab on experimentally induced otitis media in rats

OBJECTIVES

We performed a prospective randomized and controlled animal study to investigate the effects of infliximab on experimental otitis media in rats.

METHODS

Seventy-two Sprague-Dawley rats were randomly allocated to 3 study groups and 1 control group. Infliximab was injected intravenously. Histopathologic changes were determined by hematoxylin-eosin staining. Fluorescence microscopy was performed to examine the leakage of the exudates. Vascular permeability was measured by the Evans blue dye technique.

RESULTS

In comparison with the control group, we found significant differences in the extent of middle ear mucosa without active inflammation and the presence of reparable lesions in all study groups treated with infliximab. A significant reduction of extravasated Evans blue dye in all study group animals was found as compared with the control group animals.

CONCLUSIONS

This study suggests that the monoclonal tumor necrosis factor alpha antibody, infliximab, can reduce inflammatory activity in experimental otitis media in rats.

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.

O papel do Fator de Necrose Tumoral Alfa (TNF-alfa) no processo de erosão óssea presente no colesteatoma adquirido da orelha média

O colesteatoma adquirido da orelha média causa erosão óssea, com altas taxas de morbidade e mortalidade. O TNF-alfa (TNF-alfa) lambda uma das principais citocinas envolvidas neste processo. OBJETIVO: Avaliar o papel do TNF-alfa na reabsorsão óssea e a ação dele no colesteatoma. MATERIAL E MÉTODOS: Foi realizado um levantamento e uma revisão crítica da literatura. RESULTADOS: Todos os autores estudados concordam com a importância do TNF-alfa no processo de reabsorção óssea presente no colesteatoma e com o grau de destruição observado. Diferentes trabalhos demonstraram que o TNF-alfa é capaz de provocar erosão óssea, através de diferentes vias de ação. Ele pode estimular a diferenciação e a maturação dos osteoclastos ou, ainda, agir na matriz óssea expondo-a à ação dos osteoclastos. Existe a possibilidade de inibir a ação do TNF-alfa, diminuindo seus efeitos e prevenindo a perda óssea em doenças como a artrite reumatóide. Não existe, entretanto, trabalhos específicos em colesteatoma. Não existe consenso sobre a sua localização. Estas diferenças, provavelmente, ocorrem devido à distribuição dos receptores. CONCLUSÃO: O TNF-alfa, presente no colesteatoma promove a reabsorsão óssea, juntamente com outras citocinas (RANKL e IL-1), estando relacionado com a presença de complicações.

Expressions of cyclooxygenase 1 and 2 in endotoxin-induced otitis media with effusion in the rat

OBJECTIVE

Recently, a selective COX-2 inhibitor was developed and used for reducing the levels of inflammation-inducing prostaglandin (PG) whilst not inhibiting the release of protective PG by COX-1. COX-1 may be the critical isoform required for the production of PG with a homeostatic function, whereas COX-2 may be the main contributor to PG production in inflammation. The purpose of this study was to investigate COX-1 and 2 expressions in experimental endotoxin-induced OME in rats and to quantify their temporal expressions.

METHODS

In a rat model, lipopolysaccharides (LPS) were inoculated into the middle ear cavity. Middle ear mucosa and temporal bone were samples at 0, 1, 3, 6, and 12h, and on days 1, 3 and 7 after instilling either LPS or sterile PBS. RT-PCR, Western blotting and immunohistochemical staining were performed to determine the expressions of COX-1 and COX-2.

RESULTS

COX-1 mRNA and protein were detected in normal middle ear mucosa but their levels did not change after endotoxin instillation. However, COX-2 was not identified in normal middle ear mucosa, but COX-2 mRNA was maximally increased at 6h after endotoxin instillation and COX-2 protein was maximally increased at 12h. COX-2 expression, by immunohistochemical staining, was identified only at 12h after endotoxin injection.

CONCLUSIONS

In this study, the basal expressions of COX-1 and COX-2 mRNA and protein in middle ear mucosa, as well as their regulations by endotoxin were investigated. COX-1 was not induced in middle ear mucosa by endotoxin whereas COX-2 was induced within 12h of stimulation. Our findings indicate that COX-2 inhibitor administration for the relief of inflammation should be considered within 12h of the initiation of an inflammatory process. These findings may provide an understanding of the mechanisms regulating PG formation in infection of the middle ear cavity.

The role of Tumor Necrosis Factor -Alpha (TNF-α) in bone resorption present in middle ear cholesteatoma

Summary

Cholesteatoma may cause bone erosion, with high morbidity and mortality rates. Tumor Necrosis Factor - Alpha (TNF-a) is one of the main cytokines involved in this process. Our goal was to evaluate the role of TNF-a in Bone Resorption and its effect on cholesteatoma.

Material and Methods

analysis and critical literature review.

Results

Different studies have demonstrated that TNF-a is capable of causing bone erosion. It may stimulate the differentiation and maturation of osteoclasts or it may act on the bone matrix, exposing it to the action of the osteoclasts. It is possible to inhibit TNF-a, reducing its effects and prevent bone loss in illnesses such as rheumatoid arthritis, and there has been no specific investigation regarding cholesteatomas. All studies agree on the importance of TNF-a in the bone resorption process present in cholesteatomas, and on the degree of destruction observed; however, there is no consensus as to its location. These differences are probably due to receptor site.

Conclusion

TNF-a, present in cholesteatomas, promotes bone resorption, along with other cytokines (RANKL and IL-1) related to complications.

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.

Soluble cytokine receptors in biological therapy

Due to their fundamental involvement in the pathogenesis of many diseases, cytokines constitute key targets for biotherapeutic approaches. The discovery that soluble forms of cytokine receptors are involved in the endogenous regulation of cytokine activity has prompted substantial interest in their potential application as immunotherapeutic agents. As such, soluble cytokine receptors have many advantages, including specificity, low immunogenicity and high affinity. Potential disadvantages, such as low avidity and short in vivo half-lifes, have been addressed by the use of genetically-designed receptors, hybrid proteins or chemical modifications. The ability of many soluble cytokine receptors to inhibit the binding and biological activity of their ligands makes them very specific cytokine antagonists. Several pharmaceutical companies have generated a number of therapeutic agents based on soluble cytokine receptors and many of them are undergoing clinical trials. The most advanced in terms of clinical development is etanercept (Enbrel, Immunex), a fusion protein between soluble TNF receptor Type II and the Fc region of human IgG1. This TNF-alpha; antagonist was the first soluble cytokine receptor to receive approval for use in humans. In general, most agents based on soluble cytokine receptors have been safe, well-tolerated and have shown only minor side effects in the majority of patients. Soluble cytokine receptors constitute a new generation of therapeutic agents with tremendous potential for applications in a wide variety of human diseases. Two current areas of research are the identification of their most promising applications and characterisation of their long-term effects.