Expression of matrix-degrading cysteine proteinase cathepsin K in cholesteatoma

Cerebellar Abscess Induced by Cochlear Fistula due to Chronic Suppurative Otitis Media

Cochlear fistulas with cholesteatoma as the primary disease have been reported frequently in the relevant literature. However, there are no reports of cochlear fistula without cholesteatoma due to chronic suppurative otitis media with intracranial complications. We report a case of cochlear fistula due to chronic otitis media that was diagnosed after the onset of a cerebellar abscess. The patient was a 25-year-old man with severe autism. He was admitted to our hospital with otorrhea from his left ear, emesis, and impaired consciousness. Computed tomography (CT) of the head showed left suppurative otitis media, left cerebellar abscess, and brainstem compression due to hydrocephalus. Right extra-ventricular drainage and brain abscess drainage were urgently performed. The next day, foramen magnum decompression and abscess drainage with partial resection of the swollen cerebellum were performed for decompression purposes. He was subsequently treated with antimicrobial therapy, but magnetic resonance imaging of the head showed an increase in the size of the cerebellar abscess. Re-examination of the temporal bone CT scans revealed a bony defect in the left cochlear promontory angle. We assumed that the cochlear fistula was responsible for the otogenic brain abscess. Thus, the patient underwent surgical closure of the cochlear fistula. After the operation, the cerebellar abscess lesion gradually shrank, and his general condition stabilized. Cochlear fistula should be considered in the management of patients with inflammatory middle ear disease associated with otogenic intracranial complications in the middle ear.

Downregulation of Calreticulin and Annexin A2 Expression in Acquired Middle Ear Cholesteatoma by 2-DE Analysis

BACKGROUND

Many factors are thought to be associated with the development of cholesteatoma, while the mechanisms of its formation remain unclear. This study aimed to identify the potential mechanisms of the proliferation and growth of cholesteatoma by analysis of the differential expressions of proteins in cholesteatoma and retroauricular skin tissue collected from the same patients.

METHODS

The present study is a retrospective study performed in an academic medical center. Comparative proteomics analyses using two-dimensional gel electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), in addition to immunohistochemical analysis, were conducted to identify differentially-expressed proteins in cholesteatoma tissue as compared with retroauricular skin tissue. Western blotting was also employed to verify the expression patterns of the specific proteins identified by 2-DE and to measure the changes in potential modulators related to cholesteatoma proliferation and growth.

RESULTS

Calreticulin (CRT) and annexin A2 (AnxA2) were identified as being differentially-expressed in cholesteatoma by 2-DE and LC-MS/MS, the results of which were in agreement with the results of immunohistochemical analysis and western blotting. Downregulation of CRT and AnxA2 were observed in cholesteatoma.

CONCLUSION

Our data suggests that CRT and AnxA2 downregulation are seen in cholesteatoma compared to retroauricular skin. We speculate that the reduced expression of CRT and the persistent inflammatory response play important roles in the epithelial proliferation of cholesteatoma.

Short-Wave Infrared Fluorescence Chemical Sensor for Detection of Otitis Media

Otitis media (OM) or middle ear infection is one of the most common diseases in young children around the world. The diagnosis of OM is currently performed using an otoscope to detect middle ear fluid and inflammatory changes manifested in the tympanic membrane. However, conventional otoscopy cannot visualize across the tympanic membrane or sample middle ear fluid. This can lead to low diagnostic certainty and overdiagnoses of OM. To improve the diagnosis of OM, we have developed a short-wave infrared (SWIR) otoscope in combination with a protease-cleavable biosensor, 6QC-ICG, which can facilitate the detection of inflammatory proteases in the middle ear with an increase in contrast. 6QC-ICG is a fluorescently quenched probe, which is activated in the presence of cysteine cathepsin proteases that are up-regulated in inflammatory immune cells. Using a preclinical model and custom-built SWIR otomicroscope in this proof-of-concept study, we successfully demonstrated the feasibility of robustly distinguishing inflamed ears from controls (p = 0.0006). The inflamed ears showed an overall signal-to-background ratio of 2.0 with a mean fluorescence of 81 ± 17 AU, while the control ear exhibited a mean fluorescence of 41 ± 11 AU. We envision that these fluorescently quenched probes in conjunction with SWIR imaging tools have the potential to be used as an alternate/adjunct tool for objective diagnosis of OM.

Cochlear Fistula in Chronic Otitis Media without Cholesteatoma

Cochlear fistula in the chronic otitis media (COM) without cholesteatoma is an extremely rare with only a few cases reported in the literature to this date. We describe a case of cochlear fistula observed in a female with COM without cholesteatoma. This report presents the first clinical case of a transtympanic iatrogenic trauma by habitual cotton swabs probably causing cochlear fistula.

Expression of Cathepsin K in Skull Base Chordoma

OBJECTIVE

The aim of this study was to explore the association between cathepsin K and the clinical characteristics of skull base chordoma (SBC).

METHODS

This study included 58 paraffin-embedded samples and 85 frozen samples of 94 patients. All clinical data corresponding to these patients were available. Immunohistochemical staining and quantitative real-time polymerase chain reaction were performed. Positive rate of immunohistochemical staining slices and delta cycle threshold value of quantitative real-time polymerase chain reaction represented the cathepsin K expression level in protein and gene level separately.

RESULTS

In protein level, expression level (EL) of invasive tumors was increased compared with noninvasive tumors (P = 0.006), EL of tumors with dura erosion was increased compared with tumors without dura erosion (P = 0.001). Tumors with septa exhibited increased EL compared with tumors without septa (P = 0.001). Tumors with lobulation exhibited increased EL compared with tumors without lobulation (P = 0.000). Higher EL of cathepsin K was associated with reduced progression-free survival (PFS) (P = 0.015). In gene level, tumors with septa showed higher EL than tumors without septa (P = 0.015), and tumors with lobulation showed higher EL than tumors without lobulation (P = 0.049). Cathepsin K EL was an independent risk factor for reduced PFS, and an increased level of cathepsin K in SBC was associated with reduced PFS (P = 0.042).

CONCLUSIONS

Increased cathepsin K expression in SBC was associated with tumor invasion and reduced PFS. The cathepsin K level in SBC also was associated with tumor stage, tumor lobulation, and septa.

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.

Increased permeability of the epithelium of middle ear cholesteatoma

OBJECTIVE

We investigated the electrical impedance of and the expressions of tight junction molecules in the cholesteatoma epithelium to provide supporting evidence for the acid lysis theory of bone resorption in middle ear cholesteatoma.

METHODS

Study subjects were patients with primary acquired middle ear cholesteatoma and those with non-cholesteatomatous chronic otitis media who underwent tympanomastoidectomy. The electrical impedance of the cholesteatoma epithelium was measured during tympanomastoidectomy by loading alternating currents of 320 Hz and 30.7 kHz. The expressions of tricellulin (MARVELD2), claudin-1 (CLDN1) and claudin-3 (CLDN3) were examined by fluorescence immunohistochemistry and quantitative reverse transcription-polymerase chain reaction.

RESULTS

The electrical impedance of the cholesteatoma epithelium was significantly lower than that of the post-auricular skin and external auditory canal skin at both 320 Hz and 30.7 kHz. Immunoreactivity for MARVELD2, CLDN1 and CLDN3 was localised mainly in the granular layer, and to lesser degree, in the horny and spinous layers in both the cholesteatoma tissue and post-auricular skin. Fluorescence intensity was moderate for MARVELD2, weak for CLDN1 and strong for CLDN3. The expressions of MARVELD2, CLDN1 and CLDN3 mRNA were significantly lower in the cholesteatoma tissue than in the post-auricular skin.

CONCLUSIONS

These results indicate the increased permeability of the cholesteatoma epithelium and suggest that this change is, at least partially, dependent on the decrease in the expressions of the tight junction molecules. This evidence supports the acid lysis hypothesis of bone resorption in cholesteatoma.

Autograft ossiculoplasty in cholesteatoma surgery: a histological study

CONCLUSION

The results of the present study reject the hypothesis that epithelial inclusions into the ossicles could cause cholesteatoma recurrences, but strongly suggest the performance of a safe cleaning procedure for ossicular remnants to make them usable in ossiculoplasty in patients with partially or non-encapsulated cholesteatoma.

OBJECTIVE

The aim of the study was to define, before any sort of cleaning procedure, if there is any epithelial inclusion inside the ossicles of patients with cholesteatoma and if the findings could be correlated with surgical aspect of cholesteatoma.

METHODS

The specimens used for this study comprised 19 mallei and 15 incudes, which were obtained intraoperatively from 24 patients. Each ossicle was grouped on the basis of the intraoperative aspect of the cholesteatoma as follows. Grade 1: 10 ossicles obtained from encapsulated cholestatoma, non-invasive, easily cleavable. Grade 2: 14 ossicles obtained from partially encapsulated cholesteatoma, non-invasive, not easily cleavable. Grade 3: 10 ossicles obtained from non-encapsulated cholesteatoma, invasive, not cleavable. Two stapes and one malleus were taken from patients who underwent middle ear surgery for conductive hearing loss and were used as controls. The ossicles were examined histopathologically after removal.

RESULTS

Our results do not show any epithelial inclusion inside the ossicles independently from the macroscopic aspect or growing aggressiveness of cholesteatoma. In addition there was no infiltration of inflammatory cells in grade 1, but it was present in one incus (7.1%) of grade 2 and in five ossicles (50%) of grade 3. In ossicles of grade 3 up to four layers of epithelial cells were found on the surface of the ossicles.

Differential gene expression in cholesteatoma by DNA chip analysis

OBJECTIVES/HYPOTHESIS

In contrast to normal epithelium, the desquamating stratified squamous epithelium of temporal bone cholesteatoma characteristically exhibits sustained hyperproliferative growth and a capacity for bone erosion. We conducted genome-wide microarray analyses to determine the molecular nature of cholesteatoma's biological processes and identify disease-associated, altered gene activity. We tested the hypothesis that genes contributing to the pathophysiology of cholesteatoma are differentially expressed compared to control tissue.

STUDY DESIGN

Prospective experimental analysis.

METHODS

Using new, enhanced microarray platforms and well-annotated human transcriptome probes, we measured global gene expression levels in surgical specimens of cholesteatoma and in the corresponding normal postauricular skin in four patients. Genes of interest were verified by quantitative real time reverse transcriptase polymerase chain reaction analyses using cholesteatoma and postauricular sample pairs (n = 13). External auditory canal skin from six additional patients was also evaluated as a normal control. Immunohistochemistry detected protein expression in tissue sections and the cells involved.

RESULTS

DNA chip analyses identified 282 differentially expressed genes in cholesteatoma compared to control samples. Of these, 104 genes were upregulated and 178 were downregulated. Ontological classifications indicate relationships to cellular processes including receptor binding, cell communication and motion, vitamin metabolism, and cytokine-mediated inflammation. Based on potential involvement in disease pathology, 10 genes were selected and independently verified by quantitative polymerase chain reaction. Immunohistochemical detection of transcobalamin-1 and CCL27 implicates cholesteatoma keratinocytes and dermal endothelial cells as contributors in disease processes.

CONCLUSIONS

We present a comprehensive, human genome-wide survey of disease-associated gene expression that extends the public database and provides new evidence for molecular mechanisms involved in cholesteatoma pathology. Laryngoscope, 123:S1-S21, 2013.

Cholesteatoma growth and proliferation: relevance with serpin B3

OBJECTIVES/HYPOTHESIS

The mechanisms of cholesteatoma proliferation and growth remain unclear. The objective of this study is to discover the potential mechanisms of the proliferation and growth of cholesteatoma by direct experimental assessments on cholesteatoma tissues from patients.

STUDY DESIGN

Retrospective study by the comparisons between cholesteatoma tissues and retroauricular skin tissues from the patients.

METHODS

Two-dimensional gel electrophoresis, LC-MS/MS analysis and immunohistochemistry were performed to investigate specific protein expression in cholesteatoma tissues compared with retroauricular skin tissues collected from the patients. Western blotting analysis was conducted to verify the regulation of specific proteins found by 2-DE, and to determine the changes of associated potential modulators in cholesteatoma proliferation and growth.

RESULTS

Twelve serpin B3 isoforms were found by 2-DE and identified by LC-MS/MS analysis, which is coherent with the results exhibited by immunohistochemistry and western blot. Up-regulation of STAT3 and down-regulations of cathepsin K and cathepsin L were represented using western blot.

CONCLUSIONS

The data in this study suggested serpin B3, STAT3, cathepsin K, and cathepsin L are associated with the proliferation and growth of cholesteatoma, and these proteins may be influential factors in cholesteatoma growth.

Congenital cholesteatoma involving the Eustachian tube

Cholesteatomas, classified as acquired or congenital, are non-neoplastic, keratinizing squamous epithelial lesions that can affect many different areas of the temporal bone. We present a case of a six-month-old female with chronic otorrhea who was found to have a congenital cholesteatoma originating from the Eustachian tube. Chronic pressure from cholesteatoma expansion turned the Eustachian tube into a large cavity approximately double the size of the middle ear space. This case was unusual not only in the location of the cholesteatoma but also in respect to the unusual presentation of chronic middle ear infection due to Eustachian tube obstruction.

Expression of cystatin C in human esophageal cancer

AIMS AND BACKGROUND

Cystatin C is a member of the cysteine protease inhibitors and its function is to decrease protease activity. A recent study showed that it was aberrantly expressed in many malignant tumors in association with tumor invasion and metastasis. We attempted to detect its expression in esophageal cancer tissues and adjacent reparative normal tissues.

METHODS AND DESIGN

Samples of cancers and non-cancerous esophageal tissues were obtained as matched pairs from 30 surgery patients with esophageal cancer and paraffin embedded. The expression of cystatin C in tissues was investigated by immunohistochemistry. Fisher's exact test was used to analyze the relationship between esophageal cancer tissues and adjacent normal tissues. Furthermore, mRNA was extracted, and reverse transcriptase polymerase chain reaction was performed.

RESULTS

The intensity of cystatin C immunostaining in tumor tissues was increased compared to that of adjacent normal tissues. mRNA expression of the cystatin C gene was greater in esophageal cancer than in normal tissues (P <0.05).

CONCLUSIONS

Our results indicate that cystatin C may play an important role in the pathogenesis and metastasis of esophageal cancer.

Bilateral promontory fistula due to noncholesteatomatous chronic otitis media

The authors describe a case of bilateral promontory fistula due to noncholesteatomatous chronic otitis media in a 46-year-old male. We performed both open cavity mastoidectomy and left staged ossiculoplasty. One year postoperatively, the audiogram showed an improved left air conduction threshold and maintenance of bone conduction. We suggest that noncholesteatomatous chronic otitis media can induce various destructive changes via the chronic inflammatory reaction.

Hystology findings' correlation between the ossicular chain in the transoperative and cholesteatomas

Chronic otitis media is hystopathologycaly defined as the presence of irreversible inflammatory tissue changes in the middle ear. Ossicular lesions represent the most prevalent change.

AIM

to correlate the degree of ossicular chain changes seen during surgery with the inflammatory histological degree and the thickness of the cholesteatoma perimatrix.

STUDY DESIGN

Cross-sectional study.

METHODS

Seventy-one descriptions of surgeries done in patients submitted to tympanomastoydectomy were reviewed. Cholesteatoma were collected and fixed in 10% formaldehyde. Two slides were made for each cholesteatoma, one stained with HE and another with picrossirius. Images were obtained from light microscopy and digitally processed and "blindly" analyzed using Image Pro-Plus Software. For statistical analysis we used Spearman's coefficient. Differences were considered statistically significant if P< or =0.05.

RESULTS

the ossicular chain was involved in 65 cases. The incus was the most frequently affected bone, followed by the stapes and the malleus. When the Spearman's coefficient was employed considering ossicular chain change degree with patient's age by the time of surgery, perimatrix thickness and histological degree of inflammation, correlations were not established.

CONCLUSION

Our findings indicate that ossicular chain changes are practically universal when a cholesteatoma is present. We didn't find correlations related with bone erosion and cholesteatoma's histological findings.

Correlação da cadeia ossicular no transoperatório com achados histológicos de colesteatomas

A Otite Média Crônica é definida pela presença de alterações teciduais inflamatórias irreversíveis na fenda auditiva. As lesões ossiculares são as mais prevalentes. OBJETIVO: Correlacionar o grau de comprometimento da cadeia ossicular, visualizada no transoperatório, com o grau histológico de inflamação e com a espessura da perimatriz de colesteatomas. TIPO DE ESTUDO: Estudo transversal. MÉTODOS: Descrições cirúrgicas de 71 pacientes foram revisadas. Colesteatomas coletados e fixados em formol 10% e preparadas uma lâmina em Hematoxilina-Eosina e outra em Picrossírios. A leitura foi "cega", através de imagens digitais, no ImageProPlus. A análise estatística foi realizada através do coeficiente de Spearman, sendo considerados como estatisticamente significativos os valores de P<0,05. RESULTADOS: Havia algum envolvimento da cadeia ossicular em 65 casos. O ossículo mais freqüentemente afetado era a bigorna, seguida pelo estribo e pelo martelo. Ao aplicarmos o coeficiente de Spearman entre o grau de comprometimento da cadeia ossicular com a idade do paciente à cirurgia, a espessura da perimatriz e o grau histológico de inflamação não foram detectadas correlações. CONCLUSÃO: Os nossos achados indicam que é praticamente universal o acometimento da cadeia ossicular na presença de colesteatoma. Não foi encontrada correção entre a erosão ossicular e os achados histológicos.

Biochemical properties and regulation of cathepsin K activity

Cysteine cathepsins (11 in humans) are mostly located in the acidic compartments of cells. They have been known for decades to be involved in intracellular protein degradation as housekeeping proteases. However, the discovery of new cathepsins, including cathepsins K, V and F, has provided strong evidence that they also participate in specific biological events. This review focuses on the current knowledge of cathepsin K, the major bone cysteine protease, which is a drug target of clinical interest. Nevertheless, we will not discuss recent developments in cathepsin K inhibitor design since they have been extensively detailed elsewhere. We will cover features of cathepsin K structure, cellular and tissue distribution, substrate specificity, and regulation (pH, propeptide, glycosaminoglycans, oxidants), and its putative roles in physiological or pathophysiological processes. Finally, we will review the kinetic data of its inhibition by natural endogenous inhibitors (stefin B, cystatin C, H- and L-kininogens).

Increased numbers of osteoclasts expressing cysteine proteinase cathepsin K in patients with infected osteoradionecrosis and bisphosphonate-associated osteonecrosis—a paradoxical observation?

Erosion of the bone is a common problem in patients suffering from infected osteoradionecrosis (IORN) or bisphosphonate-associated osteonecrosis (BON). Besides inflammatory mechanisms and infectious agents, osteoclasts were recently suggested to be specifically involved in the osteolytic mechanisms. We therefore investigated the immunohistochemical labeling of the cysteine proteinase cathepsin K, which plays a central role in osteoclast-mediated bone resorption, in tissue specimens of patients with BON (n=9; four male, five female; mean age=69.2 years) and IORN (n=10; nine male, one female; mean age=60.5 years), and compared the results with control specimens (n=8; six male, two female; mean age=60 years). In all cases, osteoclasts were the predominant cell type expressing cathepsin K. For semiquantitative analysis, we therefore defined osteoclasts as multinuclear giant cells attached to the bone and expressing cathepsin K. Significantly higher numbers of osteoclasts were found for both types of osteonecrosis when compared with the control group (BON+IORN vs controls: P=0.0000036). Within the pathological lesions, IORN cases exhibited significantly less osteoclasts than BON (P=0.00097). Our study verified increased numbers of osteoclasts in patients suffering from BON and IORN. Although it is known that bisphosphonates (and to a lesser extent, irradiation, too) decrease osteoclast function, these findings suggest a critical involvement of osteoclasts in the mechanisms of bone destruction in the respective lesions.

Some considerations about acquired adult and pediatric cholesteatomas

Authors debate about cholesteatomas, from the first time this word was employed, by Muller, in 1838, until the recent updates. They dissert about its definition, etiology and pathology and present basic concepts about its biology. They also make a wide review about pediatric cholesteathoma, its epidemiology and biology, and compare it with adult cholesteatoma. Finally, they describe some articles about ossicle chain erosion and its correlation with cholesteatoma perimatrix, collagen and collagenase.

Fistula of the Cochlear Labyrinth in Noncholesteatomatous Chronic Otitis Media

OBJECTIVE

To discuss the clinical aspects and management of promontory fistula of the cochlear labyrinth.

STUDY DESIGN

Case report and review of the literature.

SETTING

University hospital, tertiary referral center.

PATIENT, INTERVENTION, AND RESULTS

The authors describe an unusual case of cochlear fistula localized to the promontory discovered during tympanoplasty for noncholesteatomatous chronic otitis media in a 59-year-old woman. Bone conduction was slightly impaired after operation and hearing improved after a revision myringoplasty performed for reperforation.

CONCLUSION

Erosion of the bone of the labyrinth can also be observed in noncholesteatomatous otitis media. The presence of a fistula is not always associated with profound hearing loss. Overlying pathologic tissue can be removed without damaging the membranous labyrinth.

Algumas considerações sobre colesteatomas adquiridos pediátricos e adultos

Neste artigo, os autores dissertam sobre o tema colesteatoma, desde a primeira vez em que foi utilizada a palavra por Mueller (1838), até informações atuais. Fazem uma abordagem de sua definição, passam pela etiopatogênese e apresentam noções básicas sobre sua biologia. Ainda realizam uma ampla revisão sobre colesteatoma pediátrico, apresentam dados clínicos epidemiológicos e biológicos e mostram um paralelo com o colesteatoma em adultos. Para finalizar, descrevem alguns trabalhos sobre erosão da cadeia ossicular correlacionando-a com dados sobre a perimatriz, colágeno e colagenase.

Cathepsin B, D and K expression in adamantinomatous craniopharyngiomas relates to their levels of differentiation as determined by the patterns of retinoic acid receptor expression

AIMS

To investigate the potential predictive value of cathepsins B, D and K in a series of 51 adamantinomatous craniopharyngiomas. While almost always benign, craniopharyngiomas exhibit a high propensity to recur postsurgically and biological markers are therefore needed to predict their recurrence. We have previously demonstrated the potential predictive value of retinoic acid receptors (RARs) (Lefranc et al., J. Neurosurg. 2003; 98; 145-153).

METHODS AND RESULTS

Computer-assisted microscopy was used to determine quantitatively the immunohistochemical levels of expression of the alpha, beta and gamma RAR subtypes and cathepsins B, D and K. The levels of expression of cathepsin D and of cathepsin B correlated significantly with the levels of expression of RARbeta. The levels of expression of cathepsin K correlated significantly with the levels of expression of RARgamma.

CONCLUSIONS

Recurrent adamantinomatous craniopharyngiomas are characterized by low levels of RARbeta and high levels of RARgamma. The tendency to recurrence seems, at least partly, to relate to the fact that (i) craniopharyngiomas with low levels of RARbeta express low levels of cathepsin D, and (ii) craniopharyngiomas with high levels of RARgamma express high levels of cathepsin K.

Expression of hypoxia inducible factor 1 alpha and Von Hippel Lindau protein in human middle ear cholesteatoma

OBJECTIVE

To evaluate the role of hypoxia in cholesteatoma progression.

STUDY DESIGN

Immunohistochemical analysis of paraffin-embedded human specimens.

METHODS

Thirteen middle ear cholesteatomas and 10 samples of normal human external ear canal skin were stained immunohistochemically for the presence of hypoxia inducible factor 1 alpha (HIF 1 alpha) and Von Hippel Lindau protein. Specimens were then analyzed semiquantitatively.

RESULTS

Staining for both antibodies could be detected in all cholesteatomas (perimatrix and matrix), as well as in the samples of normal human ear canal skin. Cholesteatoma specimens showed statistically significant increased staining when compared with normal human skin and mucosa. The age of patients and relapse surgery affected immunohistochemical staining of HIF 1 alpha and Von Hippel Lindau protein.

CONCLUSIONS

Elevated staining intensities for HIF 1 alpha and Von Hippel Lindau protein in cholesteatoma tissue indicated that cholesteatoma may be hypoxic. In addition, our data indicated that relapse cholesteatomas yield a higher degree of hypoxia than ears without surgery.