Immunohistochemical analysis of the cytokeratin expression in middle ear cholesteatoma and related epithelial tissues

A new theory on the pathogenesis of acquired cholesteatoma: Mucosal traction

OBJECTIVES/HYPOTHESIS

Although the migration of its squamous outer surface of the tympanic membrane has been well characterized, there is a paucity of data available concerning the migratory behavior of its medial mucosal surface. Existing theories of primary acquired cholesteatoma pathogenesis do not adequately explain the observed characteristics of the disease. We propose a new hypothesis, based upon a conjecture that mucosal membrane interactions are the driving force in cholesteatoma.

STUDY DESIGN

A retrospective chart review and a prospective observational cohort study in rats.

METHODS

After developing the new theory, it was tested through both clinical and experimental observations. To evaluate whether impairment of middle ear mucociliary migration would influence cholesteatoma formation, a retrospective chart review evaluating cholesteatoma occurrence in a sizable population of patients with either primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) was performed. To study mucosal migration on the medial aspect of the tympanic membrane, ink tattoos were monitored over time in a rat model.

RESULTS

No cholesteatomas were identified in either PCD patients (470) or in CF patients (1,910). In the rat model, mucosa of the posterior pars tensa migrated toward the posterior superior quadrant, whereas the mucosa of the anterior pars tensa migrated radially toward the annulus.

CONCLUSION

Mucosal coupling with traction generated by interaction of migrating opposing surfaces provides the first comprehensive theory that explains the observed characteristics of primary acquired cholesteatoma. The somewhat counterintuitive hypothesis that cholesteatoma is fundamentally a mucosal disease has numerous therapeutic implications.

Large-scale proteomics differentiates cholesteatoma from surrounding tissues and identifies novel proteins related to the pathogenesis

Cholesteatoma is the growth of keratinizing squamous epithelium in the middle ear. It is associated with severe complications and has a poorly understood etiopathogenesis. Here, we present the results from extensive bioinformatics analyses of the first large-scale proteomic investigation of cholesteatoma. The purpose of this study was to take an unbiased approach to identifying alterations in protein expression and in biological processes, in order to explain the characteristic phenotype of this skin-derived tumor. Five different human tissue types (cholesteatoma, neck of cholesteatoma, tympanic membrane, external auditory canal skin, and middle ear mucosa) were analyzed. More than 2,400 unique proteins were identified using nanoLC-MS/MS based proteomics (data deposited to the ProteomeXchange), and 295 proteins were found to be differentially regulated in cholesteatoma. Validation analyses were performed by SRM mass spectrometry. Proteins found to be up- or down-regulated in cholesteatoma were analyzed using Ingenuity Pathway Analysis and clustered into functional groups, for which activation state and associations to disease processes were predicted. Cholesteatoma contained high levels of pro-inflammatory S100 proteins, such as S100A7A and S100A7. Several proteases, such as ELANE, were up-regulated, whereas extracellular matrix proteins, such as COL18A1 and NID2, were under-represented. This may lead to alterations in integrity and differentiation of the tissue (as suggested by the up-regulation of KRT4 in the cholesteatoma). The presented data on the differential protein composition in cholesteatoma corroborate previous studies, highlight novel protein functionalities involved in the pathogenesis, and identify new areas for targeted research that hold therapeutic potential for the disease.

Canine aural cholesteatoma: a histological and immunohistochemical study

Canine aural cholesteatoma is an epidermoid cyst that forms in the middle ear cavity as a rare complication of otitis media but the aetiopathogenesis remains controversial. In the present study, 13 cases of canine aural cholesteatoma were investigated histologically and immunohistochemically and compared with cases of chronic otitis. The immunohistochemical investigation was performed using the following monoclonal antibodies: anti-cytokeratins (CK) 14, 16, 8/18, and 19, and anti-Ki67. The proliferative indexes (PIs) of cholesteatomata and otitis epithelium were calculated as the percentage of Ki67 positive nuclei/total nuclei. Histologically, the cholesteatomata were composed of a hyperplastic, hyperkeratotic epithelium (matrix) resting on a fibrous perimatrix, infiltrated by inflammatory cells and devoid of cutaneous adnexa. Immunohistochemically, the cholesteatoma epithelium was CK14- and CK16-positive, and CK8/18- and CK19-negative. A similar pattern of CK expression was found in otitis externa. In otitis media, ciliated epithelium stained CK8/18- and CK19-positive in all layers, CK14-positive in the basal layers, and CK16-negative. The mean PIs in cholesteatomata and otitides were 18.8 and 17.8, respectively. The immunohistochemical pattern of CK expression in cholesteatomata, when compared with chronic otitis, was suggestive of hyperproliferative epithelium, but its origin could not be demonstrated. Comparable PI values were obtained in cholesteatoma and in chronic otitis, which confirmed that Ki67 is a valuable indicator of a hyperproliferative state, but not a predictor of aggressiveness.

Optical imaging with a high-resolution microendoscope to identify cholesteatoma of the middle ear

OBJECTIVES/HYPOTHESIS

High-resolution optical imaging is an imaging modality that allows visualization of structural changes in epithelial tissue in real time. Our prior studies using contrast-enhanced microendoscopy to image squamous cell carcinoma in the head and neck demonstrated that the contrast agent, proflavine, has high affinity for keratinized tissue. Thus, high-resolution microendoscopy with proflavine provides a potential mechanism to identify ectopic keratin production, such as that associated with cholesteatoma formation, and distinguish between uninvolved mucosa and residual keratin at the time of surgery.

STUDY DESIGN

Ex vivo imaging of histopathologically confirmed samples of cholesteatoma and uninvolved middle ear epithelium.

METHODS

Seven separate specimens collected from patients who underwent surgical treatment for cholesteatoma were imaged ex vivo with the fiberoptic endoscope after surface staining with proflavine. Following imaging, the specimens were submitted for hematoxylin and eosin staining to allow histopathological correlation.

RESULTS

Cholesteatoma and surrounding middle ear epithelium have distinct imaging characteristics. Keratin-bearing areas of cholesteatoma lack nuclei and appear as confluent hyperfluorescence, whereas nuclei are easily visualized in specimens containing normal middle ear epithelium. Hyperfluorescence and loss of cellular detail is the imaging hallmark of keratin, allowing for discrimination of cholesteatoma from normal middle ear epithelium.

CONCLUSIONS

This study demonstrates the feasibility of high-resolution optical imaging to discriminate cholesteatoma from uninvolved middle ear mucosa based on the unique staining properties of keratin. Use of real-time imaging may facilitate more complete extirpation of cholesteatoma by identifying areas of residual disease. Laryngoscope, 2012.

Comparative analysis of the expression of involucrin, filaggrin and cytokeratin 4, 10, 16 in cholesteatoma

Background and Objectives

The aim of this study is to determine whether the hyperproliferative and hyperkeratotic characters of cholesteatoma are associated with differentiation of keratinocytes in cholesteatoma by examining the localization of marker proteins, such as involucrin, filaggrin, and cytokeratins.

Materials and Methods

Immunohistochemical study was carried out in 30 cholesteatoma tissues and 10 retroauricular skins to examine the expression of involucrin, filaggrin, cytokeratin 4, 10 and 16. The staining results were graded as negative, weakly positive (<10%), moderately positive (10-70%), and strongly positive (>70%).

Results

Involucrin was strongly expressed in upper spinous, granular, and corneal layer of cholesteatoma. Filaggrin was strongly expressed in granular and corneal layer of cholesteatoma. Cytokeratin 4 was expressed in basal layer of retroauricular skin, but occasionally expressed in suprabasal layer of cholesteatoma. Cytokeratin 10 was homogenously expressed in all suprabasal layer of retroauricular skin, whereas pattern of shift to surface layer was showed in cholesteatoma. Cytokeratin 16 was moderately expressed at suprabasal layer in cholesteatoma.

Conclusions

It can be suggested that early differentiation of suprabasal layer may lead to hyperdifferentiation and hyperkeratosis. Different expression of cytokeratins possibly indicates the altered differentiation of cholesteatoma.

Cholesteatoma-associated pathogenicity: potential role of lysosomal exoglycosidases

The enzymatic profile of lysosomal exoglycosidases in middle ear cholesteatoma has not been well known. The assessment of glycoconjugate catabolism may contribute to a better understanding of cholesteatoma pathogenesis.

OBJECTIVE

The study aim was to evaluate catabolic processes of glycoproteins, glycolipids, and proteoglycans in cholesteatoma through outlining the concentration of N-acetyl-β-hexosaminidase (HEX), β-glucuronidase (GLUC), and β-galactosidase (GAL) activity as well as in serum of cholesteatoma patients and healthy volunteers.

STUDY DESIGN

Acquired cholesteatomas (n = 25) and normal retroauricular skin specimens (n = 25) were taken during surgery as well as serum from cholesteatoma patients and healthy volunteers. HEX, GAL, and GLUC activity was assessed on basis of p-nitrophenol release from derivatives of the substrate (HEX: N-acetylglucosamine i N-acetylgalactosamine, GAL from galactose, and GLUC from glucuronide).

RESULTS

The mean concentration of activity of HEX 1142.39 pKat/ml, GAL 8.90 pKat/ml, and GLUC 14.06 pKat/ml was significantly higher compared with the concentration of enzyme activity in normal tissue: HEX 267.65 pKat/ml, GAL 3.44 pKat/ml, and GLUC 3.90 pKat/ml. In the serum of cholesteatoma patients, the mean concentration of enzyme activities were as follows: HEX 641.62 pKat/ml, GAL 4.55 pKat/ml, and GLUC 12.80 pKat/ml and were significantly higher compared with the concentration of HEX activity (215.75 pKat/ml), GAL (1.89 pKat/ml), and GLUC (5.51 pKat/ml) in the serum of the healthy control group. In cholesteatoma compared with the normal tissue, there is an increase of the glycoconjugate catabolism due to significantly higher concentration of HEX, GAL, and GLUC activity in cholesteatoma. Cholesteatoma causes systemic reaction due to the increase of HEX, GAL, and GLUC activity in patient serum.

Mast cells positive for cluster of differentiation 117 protein: are they players or conductor in the orchestra of cholesteatoma?

BACKGROUND

The pathogenesis of cholesteatoma remains unclear, despite several theories. Alterations in the density of mast cells positive for cluster of differentiation 117 protein (also known as CD117) can be critical to cholesteatoma formation, due to the effect on keratinocyte growth factor production. This study aimed to investigate the potential role of these mast cells in cholesteatoma pathogenesis.

METHODS

The number and density of mast cells positive for cluster of differentiation 117 protein were immunohistochemically analysed in 52 patients: 22 with chronic otitis media alone (group one), 25 with chronic otitis media with cholesteatoma (group two) and five controls.

RESULTS

The number of these mast cells was much higher in group two (in cholesteatoma matrix tissue) than in group one (in chronic otitis media granulation tissue) or the controls (in normal post-auricular skin). The density of these mast cells was significantly greater in group two than in group one or the controls (p < 0.05). The number and density of these mast cells was much greater in group one than in controls (p < 0.01).

CONCLUSION

Mast cells positive for cluster of differentiation 117 protein could play a role in cholesteatoma formation. Further investigation of the role of these mast cells in cholesteatoma may suggest new ways of addressing this disorder, and may enable the development of targeted treatments.

The role of inhibitor of DNA-binding (Id1) in hyperproliferation of keratinocytes: the pathological basis for middle ear cholesteatoma from chronic otitis media

OBJECTIVES

A hallmark of cholesteatoma is hyperproliferation of keratinocytes with abundant production of keratins in the middle ear under chronic inflammatory conditions. However, little is known about the driving force of cellular proliferation and keratin production of cholesteatomal matrix. The purpose of this study was to investigate the cellular proliferation and keratin production of keratinocytes under the influence of Id1, a candidate transcription factor to cell proliferation.

MATERIALS AND METHODS

Keratinocytes were transfected with Id1 and the responses of keratinocytes to Id1 were studied by using cellular and molecular biologic methods.

RESULTS

Id1 positively contributed to the cell cycle progression and negatively to the p16(Ink4a) downregulation via the nuclear factor-kappa B (NF-κB)/cyclin D1 pathway. Id1 significantly increased the promoter activity of NF-κB which, in turn, up-regulated the expression of cyclin D1 and keratin 10 in keratinocytes. Specific NF-κB inhibitors (pyrrolidine dithiocarbamate, PDTC), or dominant-negative inhibitor (I kappa B alpha mutant, IκBαM) abrogated the Id1-induced cell proliferation and keratin 10 production whereas p65, a subunit of the NF-κB heterodimer and an enhancer of the NF-κB activity, strengthened the Id1-induced cell proliferation and keratin 10 production.

CONCLUSIONS

Id1 contributed to hyperproliferation of keratinocytes via enhancement of cell cycle progression, removal of cell cycle inhibition, and simultaneously increased keratin production.

Identification of Id1 in acquired middle ear cholesteatoma

OBJECTIVES

To determine (1) the relationship between chronic inflammatory changes in the ossicular chain area (OCA) and the formation of cholesteatoma and (2) the correlates between aberrant gene expression and abnormal proliferation of cholesteatoma.

METHODS

Two hundred sixty-four ears with chronic otitis media that had undergone ear surgery were included in this study for statistical analysis of the relationship between abnormalities in the OCA and cholesteatoma. Fourteen middle ear cholesteatoma specimens were collected for immunohistochemical analysis of candidate molecules involved in the abnormal proliferation of keratinocytes. A cell model was used for verification of candidate molecule involvement.

RESULTS

The formation of cholesteatoma was accompanied by chronic inflammatory changes in the OCA, including granulated tissue, adhesion, and stagnating effusion. The inhibitor of the DNA-binding (Id1) gene, which is involved in controlling cell cycle progression, was abundantly expressed in cholesteatoma epithelium. In vitro studies indicate that Id1 regulated the expression of nuclear factor kappaB, cyclin D1, proliferating cell nuclear antigen, and cell cycle progression of keratinocytes,

CONCLUSIONS

Chronic inflammation in the OCA is closely related to the formation of cholesteatoma. The Id1/nuclear factor kappaB/cyclin D1/proliferating cell nuclear antigen signaling pathway is involved in the abnormal proliferation of keratinocytes in acquired cholesteatoma.

Evidence-based review of aetiopathogenic theories of congenital and acquired cholesteatoma

Cholesteatoma is a non-neoplastic, keratinising lesion which has two forms: congenital and acquired. Congenital cholesteatoma develops behind a normal, intact tympanic membrane, whilst acquired cholesteatoma is associated with a defect in the tympanic membrane. The pathological substrate of cholesteatoma is keratinising stratified squamous epithelium, but the origin of this epidermal tissue in the middle ear is controversial. Here, we review the most relevant and recent evidence for the principal aetiopathogenic theories of both forms of cholesteatoma, in the light of recent otopathological findings. Congenital cholesteatoma is most plausibly explained by the persistence of fetal epidermoid formation. Conclusive 'proof' awaits the unambiguous demonstration of the metamorphosis of an epidermoid nidus into a lesion in vivo. Acquired cholesteatoma may develop by various mechanisms: immigration, basal hyperplasia, retraction pocket and/or trauma (iatrogenic or non-iatrogenic). However, squamous metaplasia of the normal cuboidal epithelium of the middle ear is a highly unlikely explanation. Chronic inflammation seems to play a fundamental role in multiple aetiopathogenic mechanisms of acquired cholesteatoma. Therefore early treatment of inflammatory conditions might reduce their sequelae, perhaps by preventing the development of hyperplastic papillary protrusions. Continued otopathological, cellular and molecular research would enhance our limited understanding of cholesteatoma and may lead to new therapeutic strategies for this erosive disease, which often defies surgical treatment.

Ear canal keratinocyte culture: clinical perspective

HYPOTHESIS

Autologous epidermal sheets obtained by cultivating keratinocytes of the external auditory meatus can be used to repair cutaneous defects of the ear canal. The Rheinwald and Green method has been used to know whether the produced epidermal layer preserves its specificities after the culture.

BACKGROUND

Using a split-thickness skin graft during a functional ear atresia surgery does not allow for the restitution of external auditory canal self-cleaning. Some authors cultivated external auditory meatus keratinocytes and showed migration capacities of these colonies.

METHODS

Samples of preauricular skin and of the bony part of the external auditory canal were harvested from 10 patients. Keratinocytes were extracted and cultured until an epidermal sheet was obtained. The output, the keratinocyte plating efficiency, and the production delay were measured during the culture. Culture product sections and biopsy sections were examined using optical microscopy after standard coloration and indirect immunohistochemistry.

RESULTS

Nine epidermal layers from 10 biopsies were obtained in each group. A significant difference between external auditory meatus and preauricular keratinocyte plating efficiency was highlighted. The average production delay of 23 cm2 external auditory canal and preauricular epidermal layers was 21 days. There was no difference in the cytokeratine expression between external auditory canal and preauricular skin, nor between external auditory canal and preauricular culture products. All cultures expressed the cytokeratine 5 characteristic of stratifying epithelium.

CONCLUSION

The Rheinwald and Green keratinocyte culture method allows the production of ear canal-stratified epidermal sheets, which can be used for external ear reconstruction.

Utilization of fresh human tympanic membranes for structural analysis and cytokeratin immunocytochemistry implementing resin techniques

CONCLUSIONS

The results of this study have demonstrated for the first time that tympanic membrane (TM) structure is preserved following removal of fresh, normal tissue from patients undergoing surgery. Greater clarity has been demonstrated using resin sections than in previous studies on paraffin sections. Of particular note, cytokeratin (CK) immunocytochemistry was successfully performed on resin sections, which has not been previously reported. This may have potential applications for future work involving tissues that express CKs.

OBJECTIVES

To analyse the structure of normal, fresh human TM specimens after surgical removal and to evaluate their CK immunocytochemistry using resin techniques, neither of which have been demonstrated previously.

MATERIAL AND METHODS

Seven TM specimens were removed during surgery and then preserved in a modified Karnovsky's fixative. Semi-thin and thin sections were examined by means of light and electron microscopy, respectively. For comparison purposes, paraffin block-embedded specimens were also sectioned. CK immunocytochemistry was performed on semi-thin sections using standard immunoperoxidase techniques, with expression being demonstrated using light microscopy.

RESULTS

The three-layer architecture of the TM was preserved. The morphology of the TM was vastly superior in the semi-thin resin sections than in the thicker paraffin sections. The outer, middle and inner layers were clearly demonstrated. The integrity of the outer epithelial layer was maintained, with an outer keratinizing stratum corneum and underlying stratum granulosum, stratum spinosum and stratum basale layers resting on the basal lamina. The thin inner mucosal layer was also viable, consisting of simple squamous or cuboidal cells. Preservation of the middle lamina propria was achieved, with demonstration of the outer radial and inner circular fibres. CK immunocytochemistry utilizing resin techniques provided excellent staining of CK 7 and 8 in the inner layer, with positive staining of CK 5 and 10 in the outer layer.

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.

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 cholesteatoma, 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.

Photodynamic effect of argon and diode laser on cholesteatoma cell cultures after intravital staining with absorption enhancers

Chronic epitympanic otitis media, or chronic suppurative osteitis, is a destructive form of chronic middle-ear inflammation. The therapy of choice is complete surgical removal of the squamous epithelium from the middle ear. It is often impossible to inspect all areas of the middle ear with the posterior canal wall intact. Not all recesses can be reliably monitored with the microscope, particularly in the area of the antrum and hypotympanum. Residual squamous epithelium here causes frequent recurrences following cholesteatoma surgery. This study examines the effect of argon and diode lasers on cholesteatoma tissue. The aim is to develop a laser treatment selectively directed against cholesteatoma cells that can be performed after cholesteatoma surgery to eliminate any residual squamous epithelium. Intraoperatively harvested monolayer-cultured cholesteatoma cells stained in vivo with various absorption enhancers served as the in vitro examination model. Argon (499 nm) and diode lasers (810 nm) were applied since their irradiation has an appropriate tissue penetration depth and is absorbed by various chromophores such as neutral red (475-500 nm), fluorescein (488 nm), and indocyanine green (790-810). Intracellular staining of cultured cells increased the optical density at the wavelength corresponding to the dye. Neutral red damaged 50-60% of cultured cells merely by intracellular accumulation at high concentrations. An additive cell destruction of about 30% was achieved by also applying argon laser irradiation. Fluorescein diacetate caused no appreciable stain-induced damage to cultured cholesteatoma cells. Argon laser irradiation destroyed up to 60% of the cultures. Indocyanine green resulted in only minor damage to cultured cells. The diode laser destroyed up to 60% of the irradiated cells. Selective staining of cholesteatoma cells was not achieved with any of the dyes examined. Thus, other stained tissue could be damaged. Staining and subsequent laser irradiation destroys up to 60% of cultured cholesteatoma cells. Unstained irradiated cells are not affected. Indocyanine green and fluorescein are nontoxic and may thus be used as absorption enhancers. The diode and argon lasers appear to be basically suitable. Cell staining is not selective, i.e., other tissues would also be stained and damaged. To avoid such unwanted damage, it would be desirable to couple the chromophore to a specific antibody that binds only to cholesteatoma cells.

Cytokeratin expression pattern in congenital and acquired pediatric cholesteatoma

Pediatric cholesteatoma can be classified as congenital or acquired based on clinical criteria. We studied the expression patterns of five distinctive cytokeratins in both types of cholesteatoma in order to improve understanding of their pathogenesis and origin. A comparable expression pattern for CK10, CK14, CK18, CK19 and 34betaE12 antigens was found in the matrix of congenital and acquired pediatric cholesteatoma. Our results demonstrate that congenital and acquired pediatric cholesteatoma exhibit an identical cytokeratin distribution pattern, suggesting that they share a common origin. Therefore, it seems possible that a portion of the so-called "acquired" cholesteatoma may actually originate from advanced congenital cholesteatoma with secondary destruction of the tympanic membrane in the pediatric patient population.

Immunohistochemical characterization of the epidermoid formation in the middle ear

OBJECTIVE

To study the incidence, size, and origin of epidermoid formations after accurately characterizing them by cytokeratin immunohistochemical analysis.

STUDY DESIGN

A strategy of screening sections for possible epidermoid formations in the entire eardrum area in paraffin-embedded, serially sectioned developing temporal bones was used. Unstained adjacent sections were subjected to immunohistochemical staining, to provide accurately identified epidermoid formations for a study of their appearance and size in relation to age.

METHODS

The immunohistochemical expression patterns for epidermoid cytokeratins of several antibodies at different gestational ages were determined. Then, epithelial structures suspected as epidermoid formations were characterized as epidermoid with age-appropriate antibodies in 36 paraffin-embedded temporal bones from 19 cases with an age range of 6 gestational weeks to 15 months postpartum using a novel method of antigen retrieval by heating sections in a 70 degrees C water bath.

RESULTS

Each of 22 temporal bones ranging in age from 16 weeks gestation to 8 months postpartum contained one or more, often numerous, epidermoid formations. Sizes of epidermoid formations increased significantly with increasing age. The formations were found anywhere in the annular lateral wall region of middle ear, but the majority were in the anterosuperior region. A further study of the interface between annular external canal epidermis and middle ear epithelium in a larger group suggested that epidermoid formations arise at approximately 16 gestational weeks from the external canal epidermis.

CONCLUSION

The findings indicate that epidermoid tissue in the middle ear normally originates from external canal epidermis at approximately the 16th gestational week and grows before disappearing.

Increased proliferation and migration of epithelium in advancing experimental cholesteatomas

HYPOTHESIS

Hyperproliferative and migratory process of keratinocytes are part of the pathogenesis of cholesteatoma.

BACKGROUND

Cytokeratin (CK) changes were prominent in the most rapidly expanding regions of cholesteatoma formation.

METHODS

The three types of animal model-canal ligation (CL), retraction pocket (RP), and propylene glycol (PG)-were induced in Mongolian gerbils. The monoclonal antibodies to CK1/10, CK5/6, and CK13/16 were used for immunohistochemistry. The intensity of immunostaining in the pars tensa of the tympanic membrane was measured using the densitometry and compared with respect to the stage of cholesteatoma and the type of animal model.

RESULTS

With cholesteatoma formation, CK expressions were significantly increased at the peripheral part of the pars tensa, the expanding part of cholesteatoma. Among the CKs tested, the prominent changes were observed in expression of CK13/16, a marker for hyperproliferation. Among the animal models, CK changes of CK5/6 and CK1/10 were most prominent in the CL type, whereas those of CK13/16 were more persistent in the RP type.

CONCLUSION

These results suggested that complex alterations of epidermal keratinocytes occur during cholesteatoma formation and that hyperproliferative and migratory processes play important roles in the pathogenesis of cholesteatoma.

Imunoexpressão da citoqueratina 16 e do antígeno nuclear Ki-67 no colesteatoma adquirido da orelha média

Introdução: Ocolesteatoma da orelha média é caracterizado pela presença de epitélio escamoso estratificado queratinizado nesta cavidade, causando destruição óssea e podendo levar a complicações. Algumas substâncias como a citoqueratina 16 e o Ki-67, marcadores de proliferação celular, vêm sendo utilizadas para estudar essa doença. A CK 16 é um filamento protéico, situado no citoplasma das células epiteliais, característico de epitélios hiperproliferativos. O Ki-67 é um antígeno nuclear que aparece nas células em estágio de proliferação. Objetivo: O objetivo deste trabalho foi estudar a imunoexpressão da CK 16 e do Ki-67 no colesteatoma adquirido. Forma de estudo: Clínico prospectivo. Material e Método: Foram colhidas amostras de colesteatoma de 31 pacientes submetidos à cirurgia otológica, sendo 20 adultos e 11 crianças, no período de 1998 e 2000. Essas amostras foram submetidas à análise histológica e imuno-histoquímica para estudo da expressão da CK 16 e do Ki-67 na matriz do colesteatoma. Resultado: A análise dos resultados mostrou a presença da CK 16 nas camadas suprabasais da matriz do colesteatoma e, do Ki-67, na camada basal, estendendo-se para as camadas suprabasais e, inclusive, para a camada apical da matriz. A reação aos anticorpos anti-CK 16 e Ki-67 foi heterogênea. A correlação entre a CK 16 e o Ki-67 suprabasal com variáveis morfológicas, como acantose do epitélio e hiperplasia da camada basal formando cones epiteliais em direção à perimatriz, foi positiva e significativa. Também houve relação positiva e significativa entre a CK 16 e o Ki-67 suprabasal e apical. Conclusão: Esses resultados permitem concluir que o colesteatoma tem características hiperproliferativas, expressando a CK 16 e o Ki-67 na sua matriz.

Keratin pattern in hyperkeratotic and ulcerated gastric pars oesophagea in pigs

Ulceration of the gastric pars oesophagea is a serious problem in the pig industry, and in spite of numerous studies the underlying mechanisms of the development of such ulcers remains largely unknown. The present study was designed first to test the hypothesis that the epithelium of the pars oesophagea of affected pigs would be more susceptible to the irritating action of acidic gastric content owing to a change in the pattern of expression of keratin, and second to look for a member of the keratin family that could be a suitable indicator of early lesions. Samples were collected from the gastric pars oesophagea of slaughter pigs with and without grossly visible mucosal changes, and the keratin patterns of normal and hyperkeratotic and ulcerated epithelium were compared immunohistochemically. The keratin pairs K 4/K 13, and K 5/K 14 were present in both normal and affected epithelia, and had a similar pattern of expression in both conditions. K 4 and K 13 were expressed in all the suprabasal layers, and K 5 and K 14 were expressed only in the basal and epibasal cells. Immunological reactivity with the monoclonal antibodies LL020 and LHK6-markers for hyperproliferative conditions-was present in the suprabasal layers of the epithelium of the hyperkeratotic and the ulcerated pars oesophagea but not in the normal epithelium. These results indicate that K 6 is expressed in association with the mucosal changes. The pattern of the intermediate filaments of keratin suggests that in basic to gastric ulcers in pigs there is an epithelial proliferation leading to visible hyperkeratosis.

Clinicopathological consultation. Ear cholesteatoma versus cholesterol granuloma

Cholesteatoma and cholesterol granuloma of the ear are two different pathologic conditions that have often been confused in the past, and even in the present, in the literature. The features differentiating the two lesions are presented.

Cytokeratin expression patterns by one- and two-dimensional electrophoresis in pars flaccida cholesteatoma and pars tensa cholesteatoma

Expression patterns of cytokeratins (CKs) in normal skin, in pars flaccida type cholesteatoma (PFTC), and in pars tensa type cholesteatoma (PTTC) were examined by means of one- and two-dimensional electrophoretic techniques. Both CKs 14 and 5 pair (CKs 14/5) and CKs 10/1 were found in all materials. Neither CKs 16/6 nor 19 was found in the skin. CKs 16/6 and 19 were both found in 3 out of 5 PFTCs, only CKs 16/6 in 1 out of 5 and neither CKs 16/6 nor 19 in 1 out of 5. CKs 16/6 and 19 were both found in 1 out of 3 PTTCs, only CKs 16/6 in 1 out of 3 and neither CKs 16/6 nor 19 in 1 out of 3. There was no significant difference in the CKs expression patterns between PFTC and PTTC. The expression of CKs 16/6 and 19 suggested that their matrix epithelia were hyperproliferative. However, not all of the cholesteatomas were always hyperproliferative. Patterns of the terminal differentiation of CKs 1, 5, 10 and 14 in the PFTC or the PTTC were basically the same as those in the skin. In the cholesteatoma, eack CK gradually diminished in molecular weight in the cornified layer and debris. Desmosomal proteins were abundant in skin but not in cholesteatomas.

Immunohistochemical distribution of keratin proteins in feline tissues

The immunohistochemical distribution pattern of some keratin intermediate filament proteins has been analysed in a wide range of formalin fixed, paraffin embedded feline tissues using one polyclonal and two monoclonal antibodies raised against human keratins by means of the avidin-biotin-peroxidase complex technique. Only the epithelial and mesothelial cells were stained by the three antibodies, but differences in their corresponding staining pattern were noticed. The staining reaction of the polyclonal antibody raised against human skin keratin was found in both stratified and complex epithelia, while that of the monoclonal antibody which recognizes human keratins 8 + 18 + 19 of the Moll catalogue (NCL-5D3) was restricted to some simple epithelia. The staining reaction of the monoclonal antibody which reacts with human keratins 5 + 8 of the Moll catalogue (RCK-102) covered the widest spectrum of feline epithelial tissues analysed, including stratified, complex and simple epithelia. These staining patterns of feline tissues are basically similar with respect to those of corresponding tissues in other mammalian species, although some differences were also noticed and some obvious epithelial tissues were not stained. This study confirms the broad interspecies cross-reactivity of keratin proteins antibodies and demonstrates their capability to differentiate between various types of feline epithelia and some epithelial compartments.

Antigen expression of epithelial markers, collagen IV and Ki67 in middle ear cholesteatoma. An immunohistochemical Study

The expression of epithelial markers (cytokeratins, Filaggrin, BerEp4 and EMA), collagen IV and Ki67 was studied immunohistochemically in cholesteatoma and compared with that in epidermis of meatal skin, squamous epithelium of eardrum and simple epithelium of middle ear mucosa. MNF116 (cytokeratin 10, 17, 18) stained the full layer of normal epithelium and all cholesteatoma specimens. CK10 and Filaggrin were expressed in the upper layer of epidermis but more diffusely in cholesteatoma. BerEp4 was found in the basal layer of normal epithelium but was detected in most epithelial cells in cholesteatoma matrix. Variability was observed in EMA and CK14 immunostaining. Collagen IV was localized in the basement membrane of normal epithelium with a continuously staining pattern, an observation also made in the cholesteatomas studied. However, in one of these small areas the basement membrane was not stained with collagen IV. Ki67 was expressed in nuclei of the cells in the basal layer of normal epithelium but extended to epithelial cells in the upper layers of cholesteatoma matrix. The results of the present study indicate that the expression pattern of epithelial markers in cholesteatoma corresponds to that in normal epidermis. The increasing expression of BerEp4 and Ki67 confirms the hyperproliferative nature of cholesteatoma. Whether or not the lack of expression of collagen IV in one of the cholesteatomas reflects a true degradation of the basement membrane needs further investigation in extended materials.

Expression of cytokeratins 13 and 16 in middle ear cholesteatoma

The accumulation of keratinizing epithelium in the middle ear cavity is a crucial factor in the pathogenesis of cholesteatoma. We hypothesize that keratinocytes from the skin of the ear canal migrate and hyperproliferate in response to inflammation in the middle ear cavity to cause accumulation of keratin debris. In the present study, we investigated the expression of specific cytokeratins (CKs) in the cholesteatoma matrix to determine whether cholesteatoma is a hyperproliferative disease. Cytokeratin expression was examined in cholesteatoma, meatal skin, and tympanic membrane with two monoclonal antibodies, one for both cytokeratins 13 and 16 (antibody K8.12), and another for cytokeratin 13 only (antibody KS-1A3). CK 13 (MW 51 KD) is a marker of differentiation and CK 16 (MW 48 KD) is a marker of hyperproliferation of keratinocytes. The use of immunoblot probes showed that CKs 13 and 16 were present in cholesteatoma. Immunofluorescent staining showed the presence of CK 16 in the suprabasal layer of cholesteatoma, which was located near the external ear canal. CK 13 was localized in the suprabasal layer of meatal skin and tympanic membrane. CK 13 was localized in the basal layer of the cholesteatoma, distal to the external ear canal, but not in the meatal skin and tympanic membrane. Taken together, the present data suggest that cholesteatoma is a hyperproliferative disease and that cholesteatoma expresses CK 16 near the external ear canal and transforms to express CK 13 during growth distally.

A review of the definition, terminology and pathology of aural cholesteatoma

Despite a considerable amount of discussion and research in the course of many years, aural cholesteatoma has remained a matter of controversy. This review concerns only the definition, terminology and pathology of this common and severe disease.

Cytoskeletal polypeptides: cell-type specific markers useful in investigative otorhinolaryngology

In the last decade, it has been established that eukaryotic cells possess a cytoskeleton, i.e. an integrated cytoplasmic network of microfilaments (MFs), microtubules (MTs) and intermediate filaments (IFs). Moreover, certain cell membrane specializations as well as the inner lamina of the nuclear membrane also participate in the cytoskeletal structure. Although this definition of the cytoskeleton is up to date it is obvious that the future course of cell biology will be reflected in a revised definition. While the bulk of structural polypeptides involved were characterized at regular intervals, surprisingly, the function of the cytoskeleton remained largely speculative and is still less precisely defined. The most widely postulated function concerns mechanical support and integration of diverse cellular activities and thus refers to cellular architecture. Briefly, the mechanical function is thought to involve cell movement, adhesive interaction with the extracellular matrix and neighbouring cells, as well as the stabilization of cell shape. The integrative function refers to intracellular movement, i.e. transport and positioning to the appropriate locations of organelles, intracellular particles, RNA and proteins. It has been established from numerous investigations that (certain) cytoskeletal polypeptides provide significant information about the cellular origin and differentiation state. This consideration constitutes the most prominent reflection underlying this review. Furthermore, this appreciation encourages additional efforts to explore these markers in normal and pathological conditions. The first purpose of this review is briefly to summarize our present comprehension of the molecular components of the cytoskeleton, restricted to the filamentous trinity for practical reasons. The second and main aim is to survey the field with respect to otorhinolaryngology-related issues. To the author's knowledge, this has not been dealt with in the past. In bridging this gap in the literature, I hope to provoke additional interest in one of the fastest moving areas of cell biology. A comprehensive review covering the whole cytoskeleton has been covered by Preston et al. (The Cytoskeleton and Cell Motility. Blackie, Glasgow and London, 1990, pp. 7-69, 188-191). Additional information on the participating substructures is provided in the text, inclusive of last year's reviews.