Increased expression of Dec-205, Bcl-10, Tim-3, and Trem-1 mRNA in chronic otitis media with cholesteatoma

Review of potential medical treatments for middle ear cholesteatoma

Middle ear cholesteatoma (MEC), is a destructive, and locally invasive lesion in the middle ear driven by inflammation with an annual incidence of 10 per 100,000. Surgical extraction/excision remains the only treatment strategy available and recurrence is high (up to 40%), therefore developing the first pharmaceutical treatments for MEC is desperately required. This review was targeted at connecting the dysregulated inflammatory network of MEC to pathogenesis and identification of pharmaceutical targets. We summarized the numerous basic research endeavors undertaken over the last 30+ years to identify the key targets in the dysregulated inflammatory pathways and judged the level of evidence for a given target if it was generated by in vitro, in vivo or clinical experiments. MEC pathogenesis was found to be connected to cytokines characteristic for Th1, Th17 and M1 cells. In addition, we found that the inflammation created damage associated molecular patterns (DAMPs), which further promoted inflammation. Similar positive feedback loops have already been described for other Th1/Th17 driven inflammatory diseases (arthritis, Crohn’s disease or multiple sclerosis). A wide-ranging search for molecular targeted therapies (MTT) led to the discovery of over a hundred clinically approved drugs already applied in precision medicine. Based on exclusion criteria designed to enable fast translation as well as efficacy, we condensed the numerous MTTs down to 13 top drugs. The review should serve as groundwork for the primary goal, which is to provide potential pharmaceutical therapies to MEC patients for the first time in history.

Expression of C-type lectin receptor mRNA in otitis media with effusion and chronic otitis media with and without cholesteatoma

BACKGROUND & OBJECTIVES

C-type lectin receptors (CLRs) are a family of pattern recognition receptors (PRPs). The expression of CLRs has been analyzed in other diseases but has not yet been compared in patients with otitis media with effusion (OME), chronic otitis media (COM) and COM with cholesteatoma (Chole OM). This study therefore evaluated the levels of expression of mRNAs encoding Dectin-1, MR1, MR2, DC-SIGN, Syk, Card-9, Bcl-10, Malt-1, Src, DEC-205, Tim-3, Trem-1, and DAP-12 in patients with OME, COM, and Chole OM.

METHODS

CLR mRNA levels in patients with OME, COM, and Chole OM were assessed by real-time polymerase chain reaction. The level of expression of each mRNA was compared in patients with and without bacteria, and in patients with conductive hearing loss (CHL) and sensorineural hearing loss (SNHL).

RESULTS

The patterns of expression of CLRs differed in patients with OME, COM, and Chole OM. Galectin-1 mRNA level was significantly higher in the COM than in the Chole OM group (p<0.05), and MR1 and Galectin-1 mRNA levels among patients with CHL were significantly higher in those with COM than with Chole OM (p<0.05). Galectin-1 mRNA level among patients with SNHL was also significantly higher in the COM than in the Chole OM group (p<0.05).

CONCLUSIONS

The levels of expression of mRNAs encoding the CLRs Dectin-1, MR1, MR2, DC-SIGN, Syk, Card-9, Bcl-10, Malt-1, Src, DEC-205, Tim-3, Trem-1 and DAP-12 differ among patients with OME, COM, and Chole OM.

Expression, Distribution, and Role of C-Type Lectin Receptors in the Human and Animal Middle Ear and Eustachian Tube: A Review

Otitis media (OM) is a group of inflammatory diseases of the middle ear (ME), regardless of cause or pathological mechanism. Among the molecular biological studies assessing the pathology of OM are investigations into the expression of C-type lectin receptors (CLR) in the ME and Eustachian tube (ET). To date, nine studies have evaluated CLR expression in the ME and ET. The expression of individual CLRs in mammalian ME and ET varies by species and model of OM. Assessments have shown that the patterns of CLR expression in the ME and ET vary; that CLR expression may vary by type of OM; and that the distribution and levels of expression of CLRs may depend on the presence or absence of inflammation, with variations even within the same species and same tissue. Infection of the ME and ET with various pathogens is a common cause of all types of OM, with host responses to pathogens mediated initially by the innate immune system. CLRs are important factors in the innate immune system because they act as both adhesion molecules and as pathogen recognition receptors. The expression of CLRs in OM tissues suggests that CLRs are associated with the pathogenesis of various types of OM.

Role of innate immunity in the pathogenesis of otitis media

Otitis media (OM) is a public health problem in both developed and developing countries. It is the leading cause of hearing loss and represents a significant healthcare burden. In some cases, acute OM progresses to chronic suppurative OM (CSOM), characterized by effusion and discharge, despite antimicrobial therapy. The emergence of antibiotic resistance and potential ototoxicity of antibiotics has created an urgent need to design non-conventional therapeutic strategies against OM based on modern insights into its pathophysiology. In this article, we review the role of innate immunity as it pertains to OM and discuss recent advances in understanding the role of innate immune cells in protecting the middle ear. We also discuss the mechanisms utilized by pathogens to subvert innate immunity and thereby overcome defensive responses. A better knowledge about bacterial virulence and host resistance promises to reveal novel targets to design effective treatment strategies against OM. The identification and characterization of small natural compounds that can boost innate immunity may provide new avenues for the treatment of OM. There is also a need to design novel methods for targeted delivery of these compounds into the middle ear, allowing higher therapeutic doses and minimizing systemic side effects.