Clinical-histopathological correlations in experimental otitis media: implications for silent otitis media in humans

P, B. NNR, S. R. A Cross-Sectional Study on the Status of Contralateral Ear in Cases with Otitis Media Attending a Tertiary Care Center

Background As the aeration and drainage entrances in both ears are the same, the factors that produce otitis media in one ear may also affect the other. Also, the unsolved debate is that long-standing otitis media turns into chronic otitis media (COM). Hence, this study was conducted with the objective of assessing the incidence of abnormal findings in the contralateral ear (CLE) and to find the association between the type of COM of diseased ear with the findings of CLE.

Materials and Methods A hospital-based cross-sectional study was conducted among cases with unilateral COM who visited the outpatient department of otorhinolaryngology at Chettinad Hospital and Research Institute in Chennai between November 2021 and February 2022. The study comprised 200 COM cases in all. The medical history, otoscopic examination, pure-tone audiometry, and tympanometric findings of the patient were all documented. SPSS version 20 was used to conduct the analysis.

Results About 80% of the individuals with COM in one ear exhibited some abnormalities in the CLE. The type of COM in the afflicted ear is not linked with the otoscopic findings, type of hearing loss, tympanometric findings, or overall abnormalities in the CLE. This study's findings are comparable to those of several others.

Conclusion Though there is no association between type of COM and the pathological findings in the CLE, considering the huge burden of pathological findings noted in the CLE, all cases of unilateral COM should be screened for aberrant findings in the CLE.

Macroscopic description of the external and middle ear of paca (Cuniculus paca Linnaeus, 1766)

Abstract: Paca (Cuniculus paca), one of the largest rodents of the Brazilian fauna, has inherent characteristics of its species which can conribute as a new option for animal experimantation. As there is a growing demand for suitable experimental models in audiologic and otologic surgical research, the gross anatomy and ultrastructural ear of this rodent have been analyzed and described in detail. Fifteen adult pacas from the Wild Animals Sector herd of Faculdade de Ciências Agrárias e Veterinárias, Unesp-Jaboticabal, were used in this study. After anesthesia and euthanasia, we evaluated the entire composition of the external ear, registering and ddescribing the details; the temporal region was often dissected for a better view and detailing of the tympanic bulla which was removed and opened to expose the ear structures analyzed mascroscopically and ultrastructurally. The ear pinna has a triangular and concave shape with irregular ridges and sharp apex. The external auditory canal is winding in its path to the tympanic mebrane. The tympanic bulla is is on the back-bottom of the skull. The middle ear is formed by a cavity region filled with bone and membranous structures bounded by the tympanic membrane and the oval and round windows. The tympanic membrane is flat and seals the ear canal. The anatomy of the paca ear is similar to the guinea pig and from the viewpoint of experimental model has major advantages compared with the mouse ear.

Haemophilus responses to nutritional immunity: epigenetic and morphological contribution to biofilm architecture, invasion, persistence and disease severity

In an effort to suppress microbial outgrowth, the host sequesters essential nutrients in a process termed nutritional immunity. However, inflammatory responses to bacterial insult can restore nutritional resources. Given that nutrient availability modulates virulence factor production and biofilm formation by other bacterial species, we hypothesized that fluctuations in heme-iron availability, particularly at privileged sites, would similarly influence Haemophilus biofilm formation and pathogenesis. Thus, we cultured Haemophilus through sequential heme-iron deplete and heme-iron replete media to determine the effect of transient depletion of internal stores of heme-iron on multiple pathogenic phenotypes. We observed that prior heme-iron restriction potentiates biofilm changes for at least 72 hours that include increased peak height and architectural complexity as compared to biofilms initiated from heme-iron replete bacteria, suggesting a mechanism for epigenetic responses that participate in the changes observed. Additionally, in a co-infection model for human otitis media, heme-iron restricted Haemophilus, although accounting for only 10% of the inoculum (90% heme-iron replete), represented up to 99% of the organisms recovered at 4 days. These data indicate that fluctuations in heme-iron availability promote a survival advantage during disease. Filamentation mediated by a SulA-related ortholog was required for optimal biofilm peak height and persistence during experimental otitis media. Moreover, severity of disease in response to heme-iron restricted Haemophilus was reduced as evidenced by lack of mucosal destruction, decreased erythema, hemorrhagic foci and vasodilatation. Transient restriction of heme-iron also promoted productive invasion events leading to the development of intracellular bacterial communities. Taken together, these data suggest that nutritional immunity, may, in fact, foster long-term phenotypic changes that better equip bacteria for survival at infectious sites.

Clinical management of upper and lower respiratory tract diseases caused by nontypeable Haemophilus influenzae (NTHI) is a significant socioeconomic burden. Therapies targeting the pathogenic lifestyle of NTHI remain non-existent due to a lack of understanding of host microenvironmental cues and bacterial responses that dictate NTHI persistence. Iron availability influences bacterial virulence traits and biofilm formation; yet, host sequestration of iron serves to restrict bacterial growth. We predicted that fluctuations in availability of iron-containing compounds, typically associated with infection, would impact NTHI pathogenesis. We demonstrated that transient restriction of heme-iron triggered an epigenetic developmental program that enhanced NTHI biofilm architecture, directly influenced by induced morphological changes in bacterial length. Heme-iron restricted bacteria were primed for survival in the mammalian middle ear, due in part to an observed reduction in host inflammation coinciding with a striking reduction in host mucosal epithelial damage, compared to that observed in response to heme-iron replete NTHI. Moreover, transiently restricted NTHI were more invasive of epithelial cells resulting in formation of intracellular bacterial communities. Our findings significantly advance our understanding of how host immune pressure and nutrient availability influence pathogenic behaviors that impact disease severity.

Histopathologic differences due to bacterial species in acute otitis media

OBJECTIVE

To compare selected features of histopathology in acute otitis media caused by various bacteria and examine potential differences due to bacterial species, as well as possible correlation to experimental and human clinical findings.

METHODS

Rat models of acute otitis media caused by Streptococcus pneumoniae (MC), non-typeable or type b Haemophilus influenzae (NTHI/HIB) or Moraxella catarrhalis (MC) were studied longitudinally up to 6 months after bacterial challenge. Findings related to dynamics of goblet cell density, modeling and remodeling of bone tissue structures and polyp, as well as fibrous adhesion formation and persistence are presented.

RESULTS

Middle ear goblet cell density progressed to peak 2 weeks after bacterial inoculation, thereafter gradually normalizing. However, density and accordingly middle ear secretory capacity was still significantly increased after 6 months in all bacteria, except MC. The HI species induced the highest increase. Initial osteoresorption was followed by massive osteoneogenesis, progressing to a peak after 2-3 months, followed by some degree of normalization, concurrently classic remodeling. Primarily SP, but also the HI species induced more new bone formation than MC. Mucosal polyp and fibrous adhesion formation occurred regardless of bacterial species. Most polyps appeared in the early phases and the HI species induced formation of more polyps and adhesions than the other bacteria.

CONCLUSION

Acute middle ear infection with the Haemophilus species induce the highest increase of mucosal secretory capacity, lasting for at least 6 months after the acute incident. Thus, a subsequent development of secretory otitis media seems more likely following infection with these bacteria. Equivalently, mucosal scarring observed as polyp and fibrous adhesion formation was more severe following Haemophilus infection. S. pneumoniae induced the most marked changes of bone tissue structures, seen as initial osteoresorption and subsequent osteoneogenesis. Overall, infection with M. catarrhalis induced the mildest changes.

Estudo da orelha contralateral na otite média crônica: "Efeito Orloff ®"

Introdução: A otite média crônica (OMC) representa entidade de alta prevalência e distribuição mundial. Apesar da grande quantidade de estudos publicados a respeito, ainda não há, na literatura pertinente, consenso sobre a patogênese da OMC. Uma das hipóteses é a do continuum, que apresenta a otite média crônica como uma série de eventos contínuos, onde insultos iniciais desencadeiam uma cascata de alterações. Partindo então da idéia de continuum, pesquisamos a orelha contralateral (OCL) de indivíduos com diagnóstico de OMC, descrevendo as alterações encontradas. Forma de estudo: Clínico prospectivo randomizado. Material e Métodos: Foram selecionados 108 pacientes com diagnóstico de OMC não-colesteatomatosa (OMC NC) ou colesteatomatosa (OMC C) acompanhados no ambulatório do Grupo de Pesquisa em Patologia da Orelha Média do Hospital de Clínicas de Porto Alegre. Nestes, foi realizada otoendoscopia com fibra óptica bilateral. A orelha mais estável foi considerada contralateral (OCL), sendo classificada como normal ou alterada (e as alterações descritas). Resultados: Dentre os pacientes avaliados, 59,2% portavam OMC NC e 40,8% OMC C. 46,3% de todos os pacientes apresentaram alterações significativas na OCL. Dos pacientes com OMC C, 57% apresentavam alteração na OCL, sendo que 39% dos pacientes com OMC NC tinham OCL alterada. A alteração mais freqüentemente encontrada foi retração de MT, em ambos os grupos. Conclusões: Os dados encontrados sugerem que pacientes que apresentam OMC tem maior probabilidade de apresentarem patologia na OCL, o que corrobora a idéia que a OMC se trata de um evento constitucional e não isolado da orelha média.

A new rat model of otitis media caused by Streptococcus pneumoniae: conditions and application in immunization protocols

Streptococcus pneumoniae (pneumococcus [Pn]) can be cultured from up to 50% of acute otitis media (AOM) effusions, and these bacteria are the most common cause of AOM-related complications. With the recent advent of antibiotic-resistant Pn strains, treatment of Pn infections may meet with serious difficulties. Prevention through vaccination, notably for the four most common occurring Pn serotypes in humans (i.e., Pn 6B, Pn 14, Pn 19F, and Pn 23F), is a helpful alternative. Testing of vaccine efficacy should occur in an appropriate animal AOM model, which is presented here. The four involved Pn serotypes are not pathogenic to the rat, which was chosen as the experimental animal for practical reasons. To induce a natural infection (i.e., ascending through the eustachian tube), the mucociliary clearance of the eustachian tube was impaired by infusing histamine into the tympanic cavity on 2 consecutive days before intranasal inoculation of the bacteria. With this simple protocol, high and reproducible infection rates, as determined with bacterial cultures, of Pn-induced AOM (approximately 70%) with the two major Pn serotypes 14 and 19F (Pn 14 and Pn 19F) were obtained, whereas lower infection rates (25 to 50%) with Pn 6B and Pn 23F were obtained. In this model, intranasal priming with pneumococci, as well as subcutaneous vaccination with Pn 14 tetanus toxoid-conjugated polysaccharide, induced a protective effect against the induction of otitis media with these bacteria. This shows that immunity to Pn 14 AOM can be induced by both mucosal and systemic presentations of antigen. In conclusion, we have developed an animal model for Pn-induced AOM, which is suitable for the evaluation of the protecting effect of immunization.

A feasibility study of chiropractic spinal manipulation versus sham spinal manipulation for chronic otitis media with effusion in children

BACKGROUND

Pediatric otitis media with effusion is a common and costly condition. Although chiropractors have anecdotally claimed success in treating otitis media, there is little research to support their claims.

OBJECTIVE

A pilot study was undertaken for the purpose of assessing the feasibility of conducting a full-scale randomized clinical trial investigating the efficacy of chiropractic spinal manipulative therapy (SMT) for children with chronic otitis media with effusion.

METHODS

This study was a prospective, parallel-group, observer-blinded, randomized feasibility study. Twenty-two patients, ages 6 months to 6 years, received either active chiropractic SMT or placebo chiropractic SMT. Otoscopy and tympanometry were used to create a middle ear status profile, and daily diaries were collected.

RESULTS

Five newspaper advertisements over 6 months generated 105 responses. Twenty patients subsequently qualified and were randomized into the study. Collection of tympanometric and otoscopic data proved to be challenging. Compliance with the treatment and evaluation protocols and daily diaries was excellent. There were no reports of serious side effects as a result of either the active or placebo chiropractic treatments.

CONCLUSION

Recruitment for a randomized controlled trial is feasible and could be enhanced by medical collaboration. Patients and parents are able and willing to participate in a study comparing active SMT and placebo SMT. Parents were extremely compliant with the daily diaries, suggesting that similar quality-of-life and functional status measures can be successfully used in a larger trial. We found the objective outcomes assessment involving tympanometry and otoscopy extremely challenging and should be performed by experienced examiners in future studies.

Early structural changes in the rat tympanic membrane during pneumococcal otitis media

The early inflammatory reaction in the rat tympanic membrane was studied during the first 36h following inoculation of Streptococcus pneumoniae type 3 in the middle ear cavity. Otomicroscopic examination showed only minor signs of inflammation in the early stages although changes at the light microscopic level were pronounced. This reaction differed significantly between the pars flaccida and pars tensa of the tympanic membrane. Three hours after inoculation, edema and infiltration with polymorphonuclear leukocytes and macrophages were found in the pars flaccida whereas in the pars tensa no polymorphonuclear leukocytes were noted until after 12h. This reaction was most prominent after 36h. In the pars flaccida, mitoses occurred frequently among the cells of the simple squamous epithelium, which changed into a double-layered cuboidal epithelium. These findings demonstrate that an inflammatory reaction starts earlier in the pars flaccida than in the pars tensa of the tympanic membrane.

Interactive inner-ear/middle-ear disease, including perilymphatic fistula

Pathologic interactions between the middle ear and inner ear occur with 1) congenital anomalies, 2) trauma, 3) infection/inflammation, 4) tumors, 5) granulomas, 6) ototoxic eardrops, 7) cochlear implants, 8) otosclerosis, 9) Meniere's disease (decompensated) and Meniere's disease (with perilymphatic fistula), and 10) perilymphatic hypertension. Clinical and pathological characteristics are briefly categorized in this survey. Comments are made concerning the clinical utility of exploratory tympanotomy in diagnosis and treatment of pathologic conditions in the middle ear and pathologic conditions that are interactive between middle ear and inner ear.

Historical perspectives and concepts in otitis media research at the University of Minnesota

The University of Minnesota Otitis Media Research Center, formed in 1978, comprises a multidisciplinary research team in the clinical fields of otolaryngology, pediatrics, audiology, and infectious disease as well as the basic science fields of histopathology, epidemiology, microbiology, immunology, biostatistics, pharmacology, physiology, and biochemistry. The team has focused on studies designed to elucidate the pathophysiology of the otitis media continuum, and considerable progress has been made in describing this continuum by using the basic science approaches available in the Center. The collaboration of basic and clinical scientists has created a synergy of goals, ideas, and methods leading to new hypotheses and progress, ultimately resulting in improved patient care methods.

Survey of interactions between middle ear and inner ear

Diseases with interaction between the middle ear and inner ear include 1) congenital anomalies, 2) trauma, 3) infection/inflammation, 4) tumors, 5) granulomas, 6) ototoxic eardrops, 7) cochlear implants, 8) otosclerosis, 9) Meniere's disease-decompensated, and Meniere's disease with perilymphatic fistula, and 10) perilymphatic hypertension. Clinical and pathological characteristics are briefly categorized in this survey. The clinical utility of exploratory tympanotomy in diagnosis and treatment of middle ear pathology and middle ear/inner ear interactions is commented upon.