Identification of Altered miRNAs in Cerumen of Dogs Affected by Otitis Externa.

Otitis externa is one of the most common diseases in dogs. It is associated with bacteria and yeast, which are regarded as secondary causes. Cerumen is a biological substance playing an important role in the protection of ear skin. The involvement of cerumen in immune defense is poorly understood. MicroRNAs can modulate the host immune response and can provide promising biomarkers for several inflammatory and infectious disorder diagnosis. The aims of this study were to profile the cerumen miRNA signature associated with otitis externa in dogs, integrate miRNAs to their target genes related to immune functions, and investigate their potential use as biomarkers. Cerumen was collected from healthy and otitis affected dogs and the expression of miRNAs was profiled by Next Generation Sequencing; the validation of the altered miRNAs was performed using RT-qPCR. The potential ability of miRNAs to modulate immune-related genes was investigated using bioinformatics tools. The results pointed out that 32 miRNAs, of which 14 were up- and 18 down-regulated, were differentially expressed in healthy vs. otitis-affected dogs. These results were verified by RT-qPCR. To assess the diagnostic value of miRNAs, ROC analysis was carried out, highlighting that 4 miRNAs are potential biomarkers to discriminate otitis-affected dogs. Bioinformatics showed that cerumen miRNAs may be involved in the modulation of host immune response. In conclusion, we have demonstrated for the first time that miRNAs can be efficiently extracted and quantified from cerumen, that their profile changes between healthy and otitis affected dogs, and that they may serve as potential biomarkers. Further studies are necessary to confirm their diagnostic value and to investigate their interaction with immune-related genes.

Presence of hBD-1 and hBD-2 in human cerumen and external auditory canal skin.

CONCLUSION: Human beta-defensin-1 (hBD-1) and human beta-defensin-2 (hBD-2) antimicrobial peptides present in the cerumen, which is composed of exfoliated epithelial keratin and gland secretion, might provide the first line of defense against microbes in external auditory canal (EAC) skin. OBJECTIVES: Cerumen (earwax) plays a primary role in protecting the EAC skin and tympanic membrane. Even though the protection by antimicrobial peptides present in the skin secretion has been well established, little is known about the intrinsic role of the peptides in the EAC skin and cerumen. The aim of this study was to examine the presence of important antimicrobial peptides, hBD-1 and hBD-2, in the cerumen and EAC skin. MATERIALS AND METHODS: Cerumen was collected from 20 healthy adults, and the EAC skins were obtained from 12 patients who underwent middle ear surgery with canaloplasty. The presence of hBD-1 and hBD-2 was analyzed using immunohistochemistry and Western blotting. RESULTS: In the immunohistochemical study of the EAC skin, expression of hBD-1 and hBD-2 was observed in both the epithelium and the glands. The presence of hBD-1 and hBD-2 peptides in the cerumen was confirmed by Western blotting.

Diagnóstico de presunción: Otomicosis. Estudio de 451 pacientes / Presumption diagnosis: otomycosis. A 451 patients study

La otomicosis es una enfermedad frecuente. Pretendemos dilucidar distintos criterios de esta afección estudiándola en nuestro medio. Se incluyen 451 pacientes con diagnóstico de presunción: otomicosis. Proceden de consultas otorrinolaringológicas y de médicos de familia: sólo se confirma microbiológicamente el diagnóstico en un 24,43% y en un 16,16% respectivamente. Los géneros fúngicos más abundantes son Aspergillus spp. y Candida spp. La frecuencia en la presencia de Aspergillus níger se relaciona con las distintas metodologías en la extracción de las muestras. La abundancia de Candida parapsilosis en muestras procedentes de médicos de familia se considera debida a la proliferación fúngica tras uso inadecuado de antibioterapia tópica. Se concluye que los factores predisponentes para el desarrollo de la otomicosis pueden ser evitables o tratables. Se manifiesta que la utilización de antimicóticos no es suficiente para obtener la curación completa; el tratamiento ha de ir encaminado, además, a restaurar la fisiología del conducto auditivo externo

Otomycosis is a common disease. We try to analyze the causative factors for otomycosis in our environment. Our study includes 451 patients with a presumed diagnosis of otomycosis. The patients were included by ear, nose and throat specialist and general doctors; the diagnosis was confirmed in 24.43% and 16.16% respectively. The most common fungal pathogen found was Aspergillus spp. and Candida sp. The high frecuency of Aspergillus Níger may be because of the diferent ways of gathering samples. The abundance of Candida parapsilosis in the samples that came from general doctors may be because the inadequate treatment with topic antibiotics contributes fungal proliferation. We conclude that the causative factors for otomycosis could be avoided or treated. Treatment with antifungal agents is not enought to ensure complete cure, an furthermore the treatment should be aimed to restore the physiology of the external auditory cannal

Local immune response in the skin of the external auditory meatus: an immunohistochemical study.

Cerumen plays an important role in the protection of the external auditory meatus against several kinds of damage. Its hydrophobic properties, due to the high concentration of lipids, shelter the canal from physical damages, while other components probably protect against certain microbial strains. Nevertheless there has been considerable dispute in the literature with regard to the antibacterial activity of cerumen. Because of the importance of the role of immunoglobulins (Ig) in local defense mechanisms, we attempted to study, by immunohistochemical methods, the presence and localization of the cells necessary to activate an Ig-mediated immune response and the epithelial expression of immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) in order to obtain information about a local immune response in those areas of the skin that take part in cerumen production. Our findings indicate that in the human skin of the external auditory canal the cells necessary to activate an antibody-mediated immune response were localized in the different layers of the epidermis and/or in the dermis surrounding the sebaceous and ceruminous glands and the piliary follicle, while an intense immunoreactivity for IgA and IgG was observed in the epithelial layers of the skin. The results suggest that the external auditory canal is protected from the insults of pathogens by an antibody-mediated local immune response, because all the effector components of an active local immune system are present.

[The structure of the skin of the external auditory canal and the antiviral activity of the cerumen in carnivorous mammals]. / Stroenie kozhi naruzhnogo slukhovogo prokhoda i antivirusnaia aktivnost' tserumena u khishchnykh mlekopitaiushchikh.

The structure of the meatus acusticus externus skin was studied in the sable, mink, and European polecat with a parallel estimation of antiherpetic activity of the cerumen. Morphologically, these species differ in the degree of fat cellulose development, vascularization, and association with the lymphoid tissue. Lymphocytes are present both in the tissue and along the skin gland ducts and hair follicles up to the external surface only in the sable. The cerumen samples have antiviral activity also in the sable alone. The relationship between physiological properties of the mammalian cerumen and morphogenetic features is discussed.

[The anti-infective properties of mammalian earwax]. / Ob antiinfektsionnykh svoistvakh ushnoi sery mlekopitaiushchikh.

The cerumen (earwax) of some mammals possesses antistaphylococcal, antimicrococcal and antiherpes activities. The cerumen of two thirds of individuals, irrespective of their species identity and sex, has antiviral properties. The mean chemotherapeutical index in the studied groups follows a significantly decreasing sequence: dogs, humans without signs of herpes infections, rabbits, and humans with clinically expressed herpes infection. Cerumen of almost 25% of humans of the compared groups displays the immunostimulating activity. The cerumen of all studied individuals contains yeast-like fungi. A suggestion is put forward that the products of their metabolism stimulate local release of interferon-like substances by the lymphoid tissue in the cerumen.

[On the bacteriostatic or bactericidal function of ceruminous glands secretion]. / W sprawie bakteriostatycznego lub bakteriobójczego dzialania wydzieliny gruczolów woskowinowych.

The authors present the results of their research concerning the bacteriostatic or bactericidal function of the secretion of ceruminous glands of the external auditory duct. In accordance with the statements of the other authors, neither bacteriostatic nor bactericidal function of the ear wax was discovered.

[Status of humoral defense mechanisms of the middle ear in young children with acute suppurative otitis media]. / Sostoianie gumoral'nykh zashchitnykh mekhanizmov srednego ukha pri ostrom gnoinom srednem otite u detei rannego vozrasta.

The concentration of lysozyme and immunoglobulins was measured in serum and middle ear secretion of young children suffering from acute suppurative otitis. It was found that the local synthesis of lysozyme increased. The high concentration of lysozyme and low concentration of immunoglobulins of all classes in the middle ear secretion of children aged up to three years can be associated with an immature local humoral immune response.

The human external auditory canal, secretory system--an ultrastructural study.

Human external auditory canal skin, with a special emphasis on the secretory system, was studied by light, transmission electron and scanning electron microscopy. Two types of secretory glands were observed: modified apocrine (ceruminous) and sebaceous. The sebaceous secretory cellere homogeneous; on the other hand, modified apocrine secretory cells contained heterogeneous secretory granules. They were ither dark granules or light granules. Evidence to support both the apocrine as well as the eccrine mode of secretion was noted in the modified apocrine gland. This finding is partly in agreement with early reports based on light microscopy with suggested only an apocrine mode and data based on transmission electron microscopy which showed only the eccrine mode. Significance of the secretion by the external ear canal and its role in a local immune defense system is discussed.