Acquired cholesteatoma: summary of the cascade of molecular events

The Science of Cholesteatoma

Cholesteatoma is a potential end-stage outcome of chronic ear infections that can result in the destruction of temporal bone structures with potential resultant hearing loss, vertigo, and intracranial infectious complications. There is currently no treatment apart from surgery for this condition, and despite years of study, the histopathogenesis of this disease remains poorly understood. This review is intended to summarize our accumulated knowledge of the mechanisms of cholesteatoma development and the underlying molecular biology. Attention will be directed particularly to recent developments, covering many potential pharmacologic targets that could be used to treat this disease in the future.

Unveiling the Aggressiveness of Cholesteatoma: Associating MERI with miRNA-21 & IL-6 Expression

BACKGROUND

Cholesteatoma, a destructive middle ear condition, poses challenges due to its variable clinical presentation and propensity for recurrence. Understanding its molecular underpinnings could enhance prognostication and guide therapeutic interventions. This study investigates the association between cholesteatoma aggressiveness, as assessed by the Middle Ear Risk Index (MERI), and the expression of miRNA-21 and IL-6 genes.

METHODS

A cross-sectional observational study involving 30 patients with cholesteatoma undergoing tympanomastoid exploration was conducted. MERI scores were calculated preoperatively, and cholesteatoma tissue was analyzed for miRNA-21 and IL-6 gene expression using RT-PCR. Statistical analysis was performed to correlate MERI scores with gene expression levels.

RESULTS

The majority (80%) of patients exhibited severe MERI scores, correlating with extensive middle ear pathology and necessitating canal wall-down (CWD) mastoidectomy. Higher miRNA-21 and IL-6 gene expression levels were observed in cholesteatoma tissues, indicating local aggressiveness and inflammatory activity. Significant moderate correlations were found between MERI scores and miRNA-21 (Pearson correlation = 0.579, p = 0.001) and IL-6 gene expression (Pearson correlation = 0.388, p = 0.034). Patients with severe MERI scores had elevated miRNA-21 and IL-6 levels, suggesting a more aggressive disease phenotype.

CONCLUSION

MERI scores demonstrated utility in predicting cholesteatoma aggressiveness, with higher scores correlating with elevated miRNA-21 and IL-6 expression. These findings suggest a potential role for MERI in guiding surgical decision-making and prognostication. Future research on targeted therapies based on molecular mechanisms holds promise for improving cholesteatoma management.

LEVEL OF EVIDENCE

3 Laryngoscope, 135:366-372, 2025.

Biomedical application of materials for external auditory canal: History, challenges, and clinical prospects

Biomaterials play an integral role in treatment of external auditory canal (EAC) diseases. Regarding the special anatomic structure and physiological characteristics of EAC, careful selection of applicable biomaterials was essential step towards effective management of EAC conditions. The bioactive materials can provide reasonable biocompatibility, reduce risk of host pro-inflammatory response and immune rejection, and promote the healing process. In therapeutic procedure, biomaterials were employed for covering or packing the wound, protection of the damaged tissue, and maintaining of normal structures and functions of the EAC. Therefore, understanding and application of biomaterials was key to obtaining great rehabilitation in therapy of EAC diseases. In clinical practice, biomaterials were recognized as an important part in the treatment of different EAC diseases. The choice of biomaterials was distinct according to the requirements of various diseases. As a result, awareness of property regarding different biomaterials was fundamental for appropriate selection of therapeutic substances in different EAC diseases. In this review, we firstly introduced the characteristics of EAC structures and physiology, and EAC pathologies were summarized secondarily. From the viewpoint of biomaterials, the different materials applied to individual diseases were outlined in categories. Besides, the underlying future of therapeutic EAC biomaterials was discussed.

Hypoxia-inducible factor-1α contributes to the proliferation of cholesteatoma keratinocytes through regulating endothelin converting enzyme 1 expression

Objective

Cholesteatoma is a hyperproliferative, pseudoneoplastic lesion of the middle ear characterized by aggressive growth and bone destruction. Hypoxia-inducible factor-1α (HIF-1α, also known as HIF1A) is a key transcription factor that enters the nucleus and upregulates many genes involved in cancer progression in the oxygen-free environment. This study is designed to explore the role and mechanism of HIF1A in the progression of cholesteatoma.

Methods

HIF1A and endothelin converting enzyme 1 (ECE1) levels were determined using real-time quantitative polymerase chain reaction. The protein levels of HIF1A, Cyclin D1, proliferating cell nuclear antigen, and ECE1 were measured using western blot. Cell viability, proliferation, and cell cycle progression were analyzed using cell counting kit-8, Colony formation, 5-ethynyl-2'-deoxyuridine, and flow cytometry assays. Binding between HIF-1α and ECE1 promoter was predicted by Jaspar and verified using Chromatin immunoprecipitation and dual-luciferase reporter assays.

Results

HIF1A and ECE1 were highly expressed in cholesteatoma patients and keratinocytes. Moreover, HIF1A knockdown might suppress the cell viability, proliferation, and cycle progression of cholesteatoma keratinocytes. Furthermore, HIF1A upregulated the transcription of ECE1 through binding to its promoter region.

Conclusion

HIF1A might expedite cholesteatoma keratinocyte proliferation partly by increasing ECE1 expression, providing a possible therapeutic target for the cholesteatoma treatment.

The Hyperproliferation Mechanism of Cholesteatoma Based on Proteomics: SNCA Promotes Autophagy-Mediated Cell Proliferation Through the PI3K/AKT/CyclinD1 Signaling Pathway

Cholesteatoma is a chronic inflammatory ear disease with abnormal keratinized epithelium proliferation and tissue damage. However, the mechanism of keratinized epithelium hyperproliferation in cholesteatoma remains unknown. Hence, our study sought to shed light on mechanisms affecting the pathology and development of cholesteatoma, which could help develop adjunctive treatments. To investigate molecular changes in cholesteatoma pathogenesis, we analyzed clinical cholesteatoma specimens and paired ear canal skin with mass spectrometry-based proteomics and bioinformatics. From our screen, alpha-synuclein (SNCA) was overexpressed in middle ear cholesteatoma and might be a key hub protein associated with inflammation, proliferation, and autophagy in cholesteatoma. SNCA was more sensitive to lipopolysaccharide-induced inflammation, and autophagy marker increase was accompanied by autophagy activation in middle ear cholesteatoma tissues. Overexpression of SNCA activated autophagy and promoted cell proliferation and migration, especially under lipopolysaccharide inflammatory stimulation. Moreover, inhibiting autophagy impaired SNCA-mediated keratinocyte proliferation and corresponded with inhibition of the PI3K/AKT/CyclinD1 pathways. Also, 740Y-P, a PI3K activator reversed the suppression of autophagy and PI3K signaling by siATG5 in SNCA-overexpressing cells, which restored proliferative activity. Besides, knockdown of SNCA in RHEK-1 and HaCaT cells or knockdown of PI3K in RHEK-1 and HaCaT cells overexpressing SNCA both resulted in attenuated cell proliferation. Our studies indicated that SNCA overexpression in cholesteatoma might maintain the proliferative ability of cholesteatoma keratinocytes by promoting autophagy under inflammatory conditions. This suggests that dual inhibition of SNCA and autophagy may be a promising new target for treating cholesteatoma.

Study of Angiogenic, Pro-Apoptotic, and Pro-Inflammatory Factors in Congenital and Acquired Cholesteatomas

OBJECTIVES

Despite recent advances in biomolecular research that have improved our knowledge of cholesteatoma pathogenesis, the reasons behind its highly variable clinical course are still not clarified. It has been proposed that biological signaling between peri-matrix and matrix cells could play a critical role in disease homeostasis. The aim of our study was to analyze the expression of inflammatory (IL-1β), hyper-proliferative (STAT-3, TGF-β), and angiogenic (VEGF-C, PDGFr) factors in congenital and acquired cholesteatomas (both in adults and children), which might correlate with the clinical features observed. We performed an experimental study on 37 patients (29 males and 8 females, ranging from 4 to 66 years of age) who were diagnosed with cholesteatoma between 2020 and 2021 in our institution. All patients underwent clinical, audiologic, and radiologic assessments. Bone erosion grading and staging of cholesteatoma growth were assessed through preoperative evaluation and intraoperative middle ear findings, according to the PTAM System proposed by the Japan Otological Society (2016). Retro-auricular skin specimens were intraoperatively collected in all patients. Skin and cholesteatoma samples were analyzed through histopathological, western blot, and immunohistochemical evaluations. The expression rate was measured to find out the differences between congenital and acquired cholesteatomas as well as between the adult and pediatric populations. Expression of angiogenic, inflammatory, and proliferative biomarkers is significantly increased in acquired cholesteatomas in children as compared to congenital and acquired forms in adults, in accordance with the higher stage of disease shown by imaging, surgical, and histological features. Our data suggest that pathways already supposed to be involved in the pathogenesis of cholesteatomas could be differently activated in more destructive forms, typically found in children. The identification of potential biomarkers of cholesteatoma aggressiveness could lead to more personalized management (timing of intervention, recurrence prevention) and the future identification of anti-growth/anti-proliferative agents as non-surgery therapeutic options.

A Rare Combination of Acquired Lymphangioma of the External Auditory Canal and Cholesteatoma in the Middle Ear Cavity

Lymphangioma (LM) is a rare but benign tumor derived from lymphatic malformation, which is extremely rare in the auditory canal or middle ear cavity. We presented a case of acquired lymphangioma of the external auditory canal combined with cholesteatoma in the middle ear cavity. To our best knowledge, this is the first case of combined lesions of lymphangioma and cholesteatoma in English literature.

Facial canal dehiscence, dural exposure, and labyrinthine fistula in middle ear cholesteatoma and mastoiditis

PURPOSE

To analyze the prevalence and associations of facial canal dehiscence (FCD), dural exposure, and labyrinthine fistula in chronic otitis media (COM) with and without cholesteatoma.

METHODS

This was a retrospective study performed in an academic medical center. Patients who received tympanoplasty with mastoidectomy for COM with and without cholesteatoma were included. The prevalence of FCD, dural exposure, and labyrinthine fistula in COM with and without cholesteatoma (mastoiditis) and their relationships were analyzed.

RESULTS

A total of 189 patients, including 107 (56.6%) females and 82 (43.4%) males, with 191 ears were included. There were 149 cases (78.0%) of cholesteatoma and 42 patients (22.0%) with mastoiditis. FCD was noted in 27.5% of patients with cholesteatoma and 9.5% of patients with mastoiditis. Dural exposure was found in 21 patients (14.1%) with cholesteatoma and 4 patients (9.5%) with mastoiditis. Eleven patients (7.4%) with cholesteatoma and 1 patient (2.4%) with mastoiditis had labyrinthine fistula. Patients with a labyrinthine fistula had nearly a fivefold greater chance (OR = 4.924, 95% CI = 1.355-17.896, p = 0.015) of having FCD than those without a fistula. There was a positive correlation between dural exposure and labyrinthine fistula (P = 0.011, Fisher's exact test).

CONCLUSION

FCD, dural exposure, and labyrinthine fistula are common complications in COM. These complications are more frequently observed in patients with cholesteatoma than in patients with mastoiditis. Surgeons should pay more attention to the treatment of COM.

Post-surgery cholesteatoma complicated by facial nerve paralysis: A case report from Afghanistan

INTRODUCTION

Cholesteatoma is a benign tumoral lesion of squamous epithelial cells in middle ear that can exist as congenital or acquired forms.

PRESENTATION OF CASES

A 35-year-old housewife presented to ENT clinic of a private hospital in Kabul, Afghanistan, with a complete facial nerve paralysis in the right side. In her antecedents, there is a tympanomastoidectomy due to chronic middle ear infection. First symptom was right side earache without any discharge. She started to notice a progressive nodule in the posterior-inferior side of her right ear. The patient was taken to the operating room. She underwent general anesthesia, an extensive cholesteatoma was removed, and a limited area of the fallopian canal in which facial nerve oedema or redness was evident. Post-operative House Brackmann grade was 1 on day 15 after the surgery.

DISCUSSION

Cholesteatoma is primarily managed surgically and currently there is no suitable medical substitute treatment strategy for cholesteatoma. Hearing improvement, making the ear dry and total omission of cholesteatoma are primary goals of surgical interventions in cholesteatoma management.

CONCLUSION

Cholesteatoma after surgical manipulations of middle ear is a rare complication with notable morbidity that has been reported almost from all around the world but our patient is the first reported case of cholesteatoma formation after surgical management of COM from Afghanistan that presented with facial nerve paralysis and hear decline.

Postoperative Recurrent Cholesteatoma in Rural Versus Urban Populations

OBJECTIVE

Chronic ear disease presents a unique challenge to otolaryngologists in both rural and urban settings. Cholesteatoma remains a difficult disease to treat in rural populations due to limited healthcare access and high risk of recurrence. The purpose of this study was to determine if there are differences in surgical outcomes among patients with acquired cholesteatoma residing in rural versus urban settings.

STUDY DESIGN

Single-surgeon retrospective case series with chart review.

SETTING

Tertiary care private otolaryngology practice.

PATIENTS

One hundred twenty-two patients presenting to the Kentuckiana ENT otology and neurotology practice from January 2011 to May 2017.

MAIN OUTCOME MEASURES

Surgical outcomes including recurrence, air-bone gap improvement, ossicular integrity, and complications were reviewed and compared between the rural and urban cohorts.

RESULTS

Presence of postoperative residual cholesteatoma (OR = 8.667, 95% CI = 2.022-37.141, p = 0.008) and number of surgeries per patient (OR = 5.185, 95% CI = 1.086-24.763, p = 0.024) were significantly increased among patients in rural nonmetropolitan areas. No significant differences were found when comparing risk of recurrence, size of cholesteatoma, presence of complications, air-bone gap improvement, and ossicular chain integrity. There were significantly more second-look surgeries performed in privately insured patients (OR = 8.582, 95% CI = 1.937-38.017, p = 0.001).

CONCLUSIONS

Patients in rural communities have an increased number of surgeries and postoperative risk for residual cholesteatoma compared to patients residing in urban settings. This study provides the basis for larger, multicenter, prospective examinations of outcomes among urban versus rural patients, which would enable a better understanding of difference in surgical outcomes between rural and urban cohorts.Level of Evidence: IV.

Relationship between clinicopathological characteristics and CYLD expression in patients with cholesteatoma

Middle ear cholesteatoma is a destructive disease in which inflammation plays an important role in development and progression, and there are currently no biomarkers predicting prognosis or recurrence. Cylindromatosis (CYLD), a tumor suppressor deubiquitinase, serves as a negative regulator of inflammation expressed in tissues including the middle ear. To determine the clinical significance of CYLD in acquired cholesteatoma, we evaluated CYLD expression in acquired cholesteatoma tissue by immunostaining and analyzed its correlation with clinicopathological characteristics. Our immunohistochemical analysis revealed that CYLD expression levels were varied in the tissues of acquired cholesteatoma patients. The relative expression levels of CYLD in cholesteatoma exhibited a significant correlation with the grade of otorrhea (R = 0.532, p = 0.039). Moreover, the period of epithelialization was also significantly associated with the relative expression levels of CYLD (R = 0.720, p = 0.002). In addition, CYLD expression tended to be lower in the group with recurrence. These results suggest that low CYLD expression correlates with postoperative recovery of acquired cholesteatoma, while potentially affecting the induction of recurrence. This is the first report showing that low CYLD expression correlates with accelerated disease recovery, and suggests a new aspect of CYLD as a prognostic predictor of acquired cholesteatoma.

Risk of Acquired Cholesteatoma and External Auditory Canal Stenosis in Traumatic Brain Injury: A Nationwide Population-Based Cohort Study

The aim of study is to investigate the risk of developing acquired cholesteatoma and external auditory canal (EAC) stenosis after traumatic brain injury (TBI) from the Taiwan National Health Insurance Research Database (NHIRD). Each subject was individually traced from their index date to identify those who received a diagnosis of acquired cholesteatoma and EAC stenosis. Cox regression analyses were applied to determine the risk of TBI-related acquired cholesteatoma and EAC stenosis. The follow-up data collected over 10 years were obtained from the TBI and comparison cohorts, of 455,834 and 911,668 patients, respectively. Multivariate analysis demonstrated that TBI significantly increased the risk of cholesteatoma (adjusted hazard ratio (HR), 1.777; 95% confidence interval (CI), 1.494-2.114, p < 0.001) and EAC stenosis (adjusted (HR), 3.549; 95% (CI), 2.713-4.644, p < 0.001). In our subgroup injury analysis, falls had the highest associated risk (4.308 times), followed by traffic injuries (66.73%; 3.718 times that of the control group). Otolaryngologists should not neglect the clinical importance and carefully investigate the possibility of subsequent cholesteatoma and EAC stenosis, which leads to hearing impairment in patients with TBI. Our research also shows the important role in preventing TBI, especially as a result of traffic injuries and falls.

Clinical Characteristics of Patients with Cochlear Fistulas Caused by Chronic Otitis Media with Cholesteatoma

OBJECTIVES

To analyze the clinical characteristics of cochlear fistulas (CFs) and propose a new fistula classification system with regard to the cochlea.

MATERIALS AND METHODS

A retrospective chart review was conducted between January 2008 and December 2015 to identify patients who had undergone surgery for cholesteatoma with an associated CF. The following data were collected: preoperative symptoms, findings of temporal bone computed tomography (TBCT), fistula stage, cholesteatoma classification, surgical technique, and pre- and postoperative pure-tone audiometry.

RESULTS

We analyzed a total of 159 patients, out of which 9 (5.7%) were diagnosed with a CF. The average duration of the chronic otitis media was 19.8 years. Cholesteatomas that induced CF rarely existed in the nonaggressive state; recurrent otorrhea was observed in all but one of our subjects. All the patients with CF had a distinct origin of cholesteatoma that developed from the retraction of posterior pars tensa; further, 88.9% cholesteatomas extended to and filled the sinus tympani. Preoperative audiometry revealed total hearing loss in 4 (44.4%) patients. Further, five patients with residual hearing before surgery had stage I fistulas, and the bone conduction thresholds remained stable after surgery.

CONCLUSION

Cochlear fistulas were often detected in patients with (1) a history of chronic otitis media (exceeding 10 years), (2) frequently recurring otorrhea, and (3) pars tensa cholesteatomas that extended to the posterior mesotympanum and filled the sinus tympani. Such patients can suffer from potentially severe and irreparable sensorineural hearing loss.

Comparison of changes in mitochondrial bioenergetics between keratinocytes in human external auditory canal skin and cholesteatomas from normoxia to hypoxia

Cholesteatoma has attracted many studies seeking to uncover its nature and the pathogenesis of related diseases. However, no researchers have explored the mitochondrial bioenergetics of cholesteatoma. The aim of this study was to investigate the energy demand and differential mitochondrial respiration profiles between keratinocytes in external auditory canal (EAC) skin and cholesteatoma samples cultured in normoxic (20% O₂) and hypoxic (5% O₂) conditions. Enhanced cellular proliferation of both types of keratinocytes was found in hypoxia compared to normoxia. In 20% O₂ conditions, cholesteatoma keratinocytes exhibited less mitochondrial mass, lower ATP levels, and significantly lower basal oxygen consumption rate (OCR) and reserve capacity compared to normal skin keratinocytes. In contrast, in hypoxic conditions, cholesteatoma keratinocytes showed markedly higher levels in maximal OCR and reserve capacity, as well as lower proton leak OCRs, compared to normal skin keratinocytes. Hypoxia induced the reverse mitochondrial bioenergy profile from that in normoxia between these two types of keratinocytes, implying that an adaptive change of mitochondrial respiration to oxygen fluctuations may develop in cases of cholesteatoma. Such adaptation in response to hypoxic conditions may play a role in explaining the pathogenesis of acquired cholesteatoma.

Primary Epidermoid Tumors of the Cerebellopontine Angle: A Review of 47 Cases

OBJECTIVE

To analyze disease presentation, treatment, and clinical course of a consecutive series of patients with primary cerebellopontine angle (CPA) epidermoids.

PATIENTS

Forty-seven consecutive patients with previously untreated CPA epidermoids.

INTERVENTION(S)

Observation and microsurgery.

MAIN OUTCOME MEASURES

Disease- and treatment-associated morbidity, recurrence.

RESULTS

Forty-seven patients (mean age 39 years; 53% women) were analyzed and the average duration of follow-up was 42 months. The most common presenting symptom was headache (27; 57%); 13 (28%) exhibited preoperative asymmetric sensorineural hearing loss, 3 (6%) facial nerve paresis, and 3 (6%) hemifacial spasm. Thirteen patients (28%) were initially observed over a mean interval of 56 months; however, five experienced disease progression requiring operation. Thirty-nine patients (83%) underwent surgical resection; 18 (46%) received gross total, 5 (13%) near total, and 16 (41%) aggressive subtotal resection. Three patients (8%) recurred at a median of 53 months; two after subtotal and one after gross total resection. Ninety-three percent of patients with useful hearing maintained serviceable hearing following treatment and one patient (3%) experienced mild long-term postoperative facial nerve paresis (HB II/VI). All patients with preoperative facial nerve paresis recovered normal function postoperatively. There were no episodes of stroke or death.

CONCLUSIONS

Surgical intervention is effective in alleviating symptoms of cranial neuropathy and brainstem compression from CPA epidermoids. Gross total resection is preferred; however, aggressive subtotal removal should be considered with adherent or extensive disease as reoperation rates are low, even in the setting of aggressive subtotal resection. Conservative observation with serial imaging is a viable initial strategy in asymptomatic or minimally symptomatic patients.

Is von Willebrand disease linked to cholesteatoma aetiology?

Cholesteatoma is a common clinical picture seen by otolaryngologists. The disease is characterised by an abnormal grow "of skin in the wrong place". Specifically, in acquired cholesteatoma, the main causative issue is associated with ventilatory deficits within the middle ear and results in chronic infection. Molecular science has associated the presence of specific molecules with its development, and moreover recent research suggests that deregulated angiogenesis is a crucial process in the development of cholesteatoma and its recurrence. Further, haematologists have linked von Willebrand factor and its defects (both quantitative and qualitative) to augmented angiogenesis through upregulation of the vascular endothelial growth factor and angiogenic cytokines. Thus, herewith we probed whether a relationship between von Willebrand disease and the etiopathogenesis of cholesteatoma, plays a potential role for anti-angiogenic molecules for the advent of cholesteatoma surgery adjuvant treatment.

Is There A Systemıc Inflammatory Effect of Cholesteatoma?

Introduction Inflammation causes squamous epithelial transformation of the mucosa in the middle ear cavity and plays a role in the onset, growth, spread, and recurrence of cholesteatoma.

Objectives The objective of this study is to investigate the systemic inflammatory effect in chronic otitis with cholesteatoma.

Methods The study included a total of 311 patients comprising 156 patients with a pathology diagnosis of cholesteatoma and a control group of 155 with no active inflammation. The Neutrophil-to-lymphocyte Ratio (NLR) was calculated by dividing the neutrophil value by the lymphocyte value.

Results The mean NLR was 1.94 ± 0.91 in the patients with cholesteatoma and 1.94 ± 0.85 in the control group. We determined no statistically significant difference between the groups in respect of NLR (p = 0.983). We calculated the NLR as 2.01 ± 1.00 in patients with ossicle erosion and 1.82 ± 0.69 in those without ossicle erosion, 1.86 ± 0.85 in patients with bone erosion and 1.98 ± 0.95 in those without bone erosion. We determined no statistical difference between these values (p = 0.175).

Conclusion The results of this study showed that NLR had no predictive value in respect of bone erosions and associated complications in patients with cholesteatoma. The inflammatory effect of cholesteatoma is not systemic but remains more local.

MicroRNA-21 promotes the proliferation and invasion of cholesteatoma keratinocytes

CONCLUSIONS

The present study revealed that miR-21 promotes the proliferation and invasion of cholesteatoma keratinocytes. These results provide a partial explanation for the more aggressive clinical behavior observed in cholesteatoma.

OBJECTIVE

This study aims to investigate the post-transcriptional regulatory effects that control proliferation, apoptosis, and invasion in cholesteatoma keratinocytes. In particular, the potential role of miR-21 was focused on in this study.

METHODS

Thirty cholesteatoma tissues were processed for RNA and cell culture. Cholesteatoma keratinocytes were transfected with miR-21 mimics, miR-21 inhibitors, or negative control miRNAs; and growth curves were drawn. RT-PCR was used to assess the expression levels of miR-21. EdU incorporation assay and TUNEL staining were used to assess the proliferation and apoptosis of cholesteatoma keratinocytes, respectively. The invasive abilities of cholesteatoma keratinocytes were examined using 6-well Transwell plates.

RESULTS

MiRNA-21 was upregulated when cholesteatoma keratinocytes were transfected with miR-21 mimics. Furthermore, the number of proliferative EdU + cells increased in cholesteatoma keratinocytes transfected with miR-21 mimics; and the number of TUNEL-positive cells also increased in cells transfected with miR-21 mimics. In addition, the number of migrated cells transfected with miR-21 mimics was higher, compared with migrated cells transfected miR-21 inhibitors or control miRNA.

Pathogenesis and Bone Resorption in Acquired Cholesteatoma: Current Knowledge and Future Prospectives

Cholesteatoma is a cystic non tumorous lesion of the temporal bone that has the ability to destroy nearby structures by its power to cause bone resorption and as a result, fatal complications prevail. We aimed to conduct a comprehensive review for pathogenesis of acquired cholesteatoma, bone resorption mechanisms, and offer a future vision of this serious disease. We have reviewed different theories for pathogenesis of acquired cholesteatoma including the most relevant and updated ones with special emphasis on the mechanisms of bone resorption through Medline/PubMed research using the keywords 'aetiopathogenesis, bone resorption, acquired cholesteatoma, temporal bone, and cytokines.' In order to strengthen our study, we searched the reference lists of identified reviews. Cholesteatoma is a subject of debate among otolaryngologists since it was prescribed firstly. Over many decades, several theories were postulated for aetiopathogenesis of cholesteatoma with a tendency to follow more than one theory to explain the proper nature of that disease. Until now, the mechanism of bone resorption has yet to be more clarified. In the last century, a leap has occurred in the field of biomolecular cholesteatoma research which improved our knowledge about its pathophysiology and bone destructive mechanism. However, surgery is still the only available treatment. We conclude that discovery of new therapeutic choices for cholesteatoma other than surgery by the use of anti-growth, anti-proliferative, apoptotic agents as well as medications that antagonize osteoclastogenesis should be the main concern in the future clinical and experimental research work. Also, searching for predictors of the aggressiveness of cholesteatoma can affect the timing of intervention and prevent occurrence of complications.

Identification of altered protein abundances in cholesteatoma matrix via mass spectrometry-based proteomic analysis

Background

Cholesteatoma are cyst-like structures lined with a matrix of differentiated squamous epithelium overlying connective tissue. Although epithelium normally exhibits self-limited growth, cholesteatoma matrix erodes mucosa and bone suggesting changes in matrix protein constituents that permit destructive behaviour. Differential proteomic studies can measure and compare the cholesteatoma proteome to normal tissues, revealing protein alterations that may propagate the destructive process.

Methods

Human cholesteatoma matrix, cholesteatoma-involved ossicles, and normal middle ear mucosa, post-auricular skin, and non-involved ossicles were harvested. These tissues were subjected to multiplex peptide labeling followed by liquid chromatography and tandem mass spectrometry analysis. Relative protein abundances were compared and evaluated for ontologic function and putative involvement in cholesteatoma.

Results

Our methodology detected 10 764 peptides constituting 1662 unique proteins at 95 % confidence or greater. Twenty-nine candidate proteins were identified in soft tissue analysis, with 29 additional proteins showing altered abundances in bone samples. Ontologic functions and known relevance to cholesteatoma are discussed, with several candidates highlighted for their roles in epithelial integrity, evasion of apoptosis, and immunologic function.

Conclusion

This study produced an extensive cholesteatoma proteome and identified 58 proteins with altered abundances contributing to disease pathopathysiology. As well, potential biomarkers of residual disease were highlighted. Further investigation into these proteins may provide useful options for novel therapeutics or monitoring disease status.

Assessment of Subepithelial Angiogenesis in Acquired Cholesteatoma between Pediatric and Adult Patients

Objective

The aim of this study was to compare subepithelial angiogenesis developing within the perimatrix of the cholesteatoma between pediatric and adult patients.

Methods

Sixty-one patients who underwent mastoidectomy for the first intent because of chronic otitis media with cholesteatoma between 1993 and 2013 and from whom appropriate tissue specimens were taken were included in the study. The patients were classified in the pediatric patient group if they were under the age of 18 years and the adult patient group if they were 18 years and older. Immunohistochemical staining for CD-31 was performed on new sections taken during surgery and sections prepared from archived tissues in paraffin blocks. Results were compared between the groups.

Results

A total of 61 patients, of whom 25 were pediatric and 36 were adult patients, were included in the study. The mean CD-31 immunopositive microvessel rates were 8.8 (3-15) and 6.61 (2-14) for the pediatric and adult patient groups, respectively. The difference between the groups was statistically significant (p=0.037). Correlation analysis showed a statistically significant negative correlation between the CD-31 immunopositive microvessel rates and age (p=0.036).

Conclusion

Subepithelial angiogenesis developing within the perimatrix of the cholesteatoma of the pediatric patients was more expressed than that of the adult patients.

Fascin expression in cholesteatoma: correlation with destruction of the ossicular chain and extent of disease

OBJECTIVE

Fascin is an actin-bundling protein found in cell membrane protrusions and increases cell motility. The expression of fascin in epithelial neoplasms has been described only recently. No data are available concerning the role of this protein in invasive cholesteatoma. Thus, we investigated the expression of fascin in cholesteatoma tissue and the relationship between fascin expression and intraoperative evaluation of the destruction of the ossicular chain and extent of disease.

METHOD

Cholesteatoma specimens of 28 patients and external auditory canal (EAC) skin specimens of the same patients (as the control group) were collected from mastoidectomies. Immunohistochemical technique was used to investigate the fascin expression in all cholesteatoma tissues and EAC skin specimens. Immunohistochemical staining was assessed semiquantitatively based on the thickness of epithelium. SPSS software version 16.0 (SPSS Inc., Chicago, IL, USA) was performed to statistically analyse the relationships between fascin expression and intraoperative evaluation destruction of ossicular chain and extent of the disease.

RESULTS

Immunohistochemically, there was no or very low fascin expression observed in normal epithelial cells of EAC skin, while expressed in cholesteatoma tissue. Also, fascin expression in cholesteatoma tissues was significantly correlated with destruction of ossicular chain and extent of the disease.

CONCLUSIONS

Fascin expression is usually found in cholesteatoma epithelium and is correlated with destruction of the ossicular chain and extent of disease. Considering all of the correlations between the clinical and histopathological findings, 'fascin immunoexpression scoring' may be used for histological grading of cholesteatoma.

MicroRNA let-7a suppresses the growth and invasion of cholesteatoma keratinocytes

Cholesteatomas are benign epidermally‑derived lesions of the temporal bone that are caused by migration of hyperproliferative keratinocytes into the middle ear and mastoid cavity. The molecular mechanisms that regulate the pathogenesis of cholesteatomas are currently not fully understood. The present study demonstrated the antigrowth and anti‑invasive effects of let‑7a microRNA (miRNA) on cholesteatoma keratinocytes. Let‑7a inhibited the growth of cholesteatoma keratinocytes through two different mechanisms: Restriction of the proliferation of keratinocytes by promoting cell cycle arrest in the G0/G1 phase, and the induction of apoptosis of the cells. In addition to its role in the inhibition of cell growth, let‑7a suppressed the migration and invasion of cholesteatoma keratinocytes. A mechanistic study showed that let‑7a downregulated the expression of miR‑21. Considering the function of miR‑21 in the regulation of proliferation and apoptosis, let‑7a may control cell proliferation and apoptosis by regulating miR‑21, and its targets, in cholesteatoma keratinocytes. In conclusion, the present study showed that let‑7a downregulates the expression of miR‑21, resulting in the suppression of proliferation and induction of apoptosis. The results of the present study reveal the crucial role of let‑7a miRNA in the inhibition of growth and invasion of cholesteatoma keratinocytes.

Mycological study on cholesteatoma keratin obtained during primary mastoid surgery

Objective:

Established middle-ear cleft cholesteatoma is associated with keratinous debris, which is likely to be an ideal medium for saprophytic fungal colonisation. This prospective case study aimed to explore the incidence and nature of fungal elements in cholesteatoma keratin samples obtained during primary mastoid surgery.

Methods:

All cases of middle-ear cleft cholesteatoma treated with primary mastoid surgery at the El-Sahel Teaching Hospital over a seven-month period were included. Keratinous debris obtained from the mastoid antrum was subjected to mycological analysis at the Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University. A literature search was performed to determine the clinical and pathological relevance of fungal colonisation in cholesteatoma.

Results:

Eighteen patients underwent primary mastoid surgery for cholesteatoma (nineteen ears in total) in a seven-month period starting 30 March 2013. Patients included 13 males and 5 females, with an age range of 9 to 45 years (mean 23 years). Fungal cultures were obtained from 17 keratin samples (89 per cent). Of these, five fungal isolates belonged to the dermatophyte group (21 per cent).

Conclusion:

Fungal colonisation in middle-ear cleft cholesteatoma probably plays a significant role in disease progression. Moreover, saprophytic fungal colonisation in cholesteatoma keratin may be responsible for the fetor commonly associated with the ear discharge.

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

CONCLUSION

The increased expression of Dec-205, Bcl-10, Tim-3, and Trem-1 mRNAs indicates that these pattern recognition receptors are involved in the pathogenesis of cholesteatoma.

OBJECTIVE

Changes in expression of pattern recognition receptors may be associated with immune responses in patients with cholesteatoma. We therefore assessed the levels of expression of Dec-205, Bcl-10, Tim-3, and Trem-1 mRNAs associated with innate immune responses in patients with cholesteatoma.

METHODS

Cholesteatoma specimens were collected from 23 patients diagnosed with acquired cholesteatoma from August 2010 to July 2012. The posterior auricular skin of each patient was used as control. The levels of expression of Dec-205, Bcl-10, Tim-3, and Trem-1 mRNA were assessed quantitatively using real-time RT-PCR and correlated with sex, hearing level, the presence of bacteria, and the need for repeat surgery.

RESULTS

The levels of expression of Dec-205, Bcl-10, Tim-3, and Trem-1 mRNAs were significantly higher in cholesteatoma than in control skin samples (p < 0.05 each). However, mRNA abundance was not associated with patient sex, hearing level, presence of bacteria or history of reoperation (p > 0.05 each).