A comparative immunohistochemical study of cytokeratin and vimentin expression in middle ear mucosa and cholesteatoma, and in epidermis

Keratinocyte growth factor (KGF) induces stem/progenitor cell growth in middle ear mucosa

OBJECTIVE

The middle ear epithelium is derived from the neural crest and endoderm, which line distinct regions of the middle ear cavity. In this study, we investigated the localization of stem/progenitor cells in the middle ear mucosa of adult mice and the effects of keratinocyte growth factor (KGF) on the cell kinetics of stem/progenitor cells in vivo.

METHODS

In this study, after KGF-expression vector was transfected in the ear, two kinds of thymidine analogues, BrdU and EdU, were transferred at different time points. BrdU was detected by immunohistochemistry and EdU was detected by click chemistry. We also performed immunohistochemistry using anti-Keratin14 (K14) antibody (an undifferentiated epithelial cell marker), anti-p63 antibody (a stem/progenitor cell marker) and anti-acetylated α-tubulin antibody (a ciliated epithelial cell marker).

RESULTS

A large number of EdU-positive cells were detected in the thickened mucosal epithelium of the pars flaccida and attic region at Day 1 after KGF transfection. Interestingly, in the mucosal epithelium overlying the promontory of the cochlea, many EdU-positive cells were detected. These cells were also positive for K14 and p63. The acetylated α-tubulin positive cells were reduced in the attic region at Day 1 after KGF transfection.

CONCLUSION

These findings indicate that KGF over-expression may increase stem/progenitor cell proliferation in the mucosal epithelium not only within the attic which is typical in middle ear cholesteatoma, but also overlying the promontory of the cochlea.

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.

Immunohistochemistry, a valuable tool in detection of cervical lymph node micrometastases in head and neck squamous cell carcinoma: a prospective study

The regional failure after comprehensive clearance of neck metastasis and consequent pathological report of N0 disease has been reported fairly frequently. The role of recurrence of disease in the neck in the cases has been variously reported by different authors. The light microscopy does not detect the micrometastasis and the specimen is reported negative for metastasis. The presence of micrometastasis (the reason for neck failure) has been reported by many studies as 5-58 % (mean 19.6 %). These figures are significantly high. The present study was done to ascertain the micrometastasis after comprehensive neck clearance (pN0 report). Two groups of patients were included in this study. (1) Group I included patients with N0 necks (80 patients). (2) Group II included Patients with N+ necks (107 patients). We found that 20 % case were reported N0 (Group I) in light microscopy but on immunohistochemistry these were positive for disease. 15 % upstaging was reported in N+ cases (Group 2). Immunohistochemistry has been more sensitive for cancer detection and has significantly changed the tumor staging and its consequent management.

Middle ear mucosa regeneration by grafting of artificial mucosa

CONCLUSION

Artificial middle ear mucosa (AMEM), a sheet of mucosal cells grown on collagen gel populated with fibroblasts, is useful as graft material that is able to promote mucosal regeneration after middle ear surgery.

OBJECTIVES

Regeneration of the middle ear mucosa and pneumatization of the mastoid cavity is critical for good prognosis. We examined whether implantation of AMEM into damaged middle ear cavity would promote mucosal regeneration.

MATERIALS AND METHODS

AMEM was prepared as described previously using epithelial cells and fibroblasts isolated from the rabbit middle ear. We implanted AMEM into rabbit middle ear from which mucosa had been surgically removed and evaluated its histological and functional recovery 8 weeks later. Three other groups were used for comparison: a normal control group, a mucosa-eliminated group, and a collagen-implanted group.

RESULTS

AMEM grew to be morphologically similar to the native middle ear mucosa. Electron microscope studies showed that implanted AMEM has basal lamina and cilia. AMEM implantation suppressed bone hyperplasia and granulation, leading to better mucosal regeneration. Mucosal gas exchange was also significantly improved after implantation.

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.

Melanocytes in the corneal limbus interact with K19-positive basal epithelial cells

The human corneal limbus is identified by the distinct features of the palisades of Vogt (POV), which contain pigment granules that are aligned with the microplicae of the epithelium. Although it is presumed that pigments are produced by melanocytes, the characterization of melanocytes in the limbus has not been clearly documented. We examined human limbal tissues by whole mounts and serial histological sections to localize epithelial cells containing melanin granules. Most of the pigmented cells observed by immunohistochemistry were K19 (+) cells in the basal limbal epithelium. A superimposed image revealed that melanin granules were oriented towards the apex of each K19 (+) cell, acting as a pigmented cap facing the ocular surface. Melanocytes were identified by MART1, an antigen specific to melanocyte-lineage cells. Melanocytes were shown to exist as sporadic cells with dendritic processes that extend to surrounding epithelial cells. Melanocytes were also found in light-pigmented donor tissue when visualized by the tyrosinase assay using the enzyme substrate DOPA. Since tyrosinase activity was not found in epithelial cells, the production of melanin is exclusively the role of melanocytes that comprised 5.3+/-2.7% of the total cells in cytospin samples (N=3). Melanocytes and K19 (+) epithelial cells may form a functional network similar to the melanin unit of the skin.

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.

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.

Expression patterns of cytokeratins in retraction pocket cholesteatomas

OBJECTIVES

To investigate the patterns of cytokeratin (CK) expression in retraction pocket cholesteatoma.

STUDY DESIGN

An animal model study.

METHODS

Retraction pocket cholesteatomas were induced by electrocautery of the eustachian tube orifice in 24 mongolian gerbils. They were divided into normal and cholesteatoma groups of clinical stages I to IV. The antibodies to pan-cytokeratin CK 1/10, CK 5/6, CK 4, and CK 13/16 were used for immunohistochemical staining. The intensity of staining in each group as measured with densitometry was compared regarding anatomical sites and clinical stages.

RESULTS

In retraction pocket cholesteatoma, CK expression was altered only at focal sites such as the pars tensa of the tympanic membrane. The change of CK expression was observed only at certain stages of cholesteatoma formation. In keratinocytes from cholesteatomas, CK 13/16 was overexpressed compared with control specimens, indicating hyperproliferation. The site with the most prominent change in retraction pocket cholesteatoma was somewhat different from that in canal ligation cholesteatoma in a previous study.

CONCLUSIONS

The results suggested that aural cholesteatoma is a disease with a spectrum of pathological conditions and that the transmigration and hyperproliferation process of squamous epithelium occurs in areas adjacent to the cholesteatoma.

Dissociation of intra- and extracellular domains of desmosomal cadherins and E-cadherin in Hailey-Hailey disease and Darier's disease

In order to clarify the pathomechanism of acantholysis in Hailey-Hailey disease (HHD) and Darier's disease (DD), the distribution of desmosomal and adherens junction-associated proteins was studied in the skin of patients with HHD (n = 4) and DD (n = 3). Domain-specific antibodies were used to determine the cellular localization of the desmosomal transmembrane glycoproteins (desmogleins 1 and 3 and desmocollin), desmosomal plaque proteins (desmoplakin, plakophilin and plakoglobin) and adherens junction-associated proteins (E-cadherin, alpha-catenin, beta-catenin and actin). A significant difference in staining patterns between intra- and extracellular domains of desmosomal cadherins and E-cadherin was demonstrated in acantholytic cells in both HHD and DD, but not in those in pemphigus vulgaris and pemphigus foliaceus samples used as controls. In acantholytic cells in HHD and DD, antibodies against attachment plaque proteins and intracellular epitopes of desmosomal cadherins exhibited diffuse cytoplasmic staining, whereas markedly reduced staining was observed with antibodies against extracellular epitopes of the desmogleins. Similarly, membrane staining of an intracellular epitope of E-cadherin was preserved, while immunoreactivity of an extracellular epitope of E-cadherin was destroyed. While the DD gene has been identified as ATP2A2, the gene for HHD has not been clarified. The dissociation of intra- and extracellular domains of desmosomal cadherin and E-cadherin is characteristic of the acantholytic cells in HHD and DD, and not of pemphigus. This common phenomenon in HHD and DD might be closely related to the pathophysiological mechanisms in both conditions.

Terminal differentiation of epithelial cells in middle ear cholesteatoma: investigation of patterns of expression of protein kinase C-delta and protein kinase C-eta

OBJECTIVES

The objective of this study was to elucidate the differentiation mechanism of keratinocytes in cholesteatoma.

STUDY DESIGN

To achieve the objective, we analyzed the expressions of various cellular proteins: the delta and eta isoforms of protein kinase C (PKCdelta and PKCeta), which are thought to play key roles in signal transduction in differentiation; cytokeratin 1 (CK1) and cytokeratin 10 (CK10) (cytoskeletal constitutive proteins); and involucrin (a marker of differentiation).

METHODS

The materials used in this study were tissue specimens obtained from cholesteatoma epidermis, normal external ear canal skin, normal inguinal skin, and psoriatic skin. Immunohistochemical staining techniques were applied to compare the expressions of the above proteins (i.e., PKCdelta, PKCeta, CK1, CK10 and involucrin) in those various tissues.

RESULTS

No clear differences in the patterns of expression of PKCdelta and PKCeta were found between the cholesteatoma epidermis and the normal external ear canal skin. These proteins were expressed mainly in the stratum spinosum and stratum granulosum, and their patterns of expression were almost the same as those of the CK1, CK10, and involucrin proteins.

CONCLUSION

The findings of this study indicate that the terminal differentiation of keratinocytes in the cholesteatoma epidermis is the same as in normal skin tissues. It was concluded that the growth of epidermis which has undergone hyperproliferation of keratinocytes because of increased levels of various cytokines is being regulated by means of normal terminal differentiation.

Determination of the levels of expression of sarcolectin and calcyclin and of the percentages of apoptotic but not proliferating cells to enable distinction between recurrent and nonrecurrent cholesteatomas

OBJECTIVES

To investigate in a series of cholesteatomas 1. whether subgroups of cholesteatomas with specific proliferative/apoptotic features exhibit distinct differentiation markers and 2. whether these different subgroups identified at the biological level relate to specific groups of clinically identified cholesteatomas.

STUDY DESIGN

Analysis of 55 cholesteatomas resected by the same surgeon, by means of canal wall up and canal wall down surgical procedures.

METHODS

Two differentiation markers were used: biotinylated sarcolectin (to identify sarcolectin-binding sites) and a monoclonal antibody directed against calcyclin (which is the S100A6 protein). The growth pattern in cholesteatomas was characterized at three distinct levels: 1. the cell proliferation level determined by means of the MIB-1 antibody, which enables the Ki-67 cell-cycle-related antigen to be identified on archival material; 2. the apoptosis level determined by means of the in situ labeling of nuclear DNA fragmentation (TUNEL staining); and 3. the p53 tumor suppressor gene-related product determined by means of p53 immunohistochemistry.

RESULTS

The cholesteatomas that exhibited the highest proportion of apoptotic cells were those which exhibited the highest level of sarcolectin-binding sites (i.e., sialic acids). In contrast, the cholesteatomas exhibiting the lowest level of both proliferation and apoptosis showed the highest level of calcyclin. Recurrent cholesteatomas can be identified from nonrecurrent ones on the basis of three features, namely, the level of apoptotic cells, the way in which the apoptotic cells are distributed (i.e., homogeneously vs. heterogeneously), and the percentage of calcyclin-positive cells.

CONCLUSIONS

The present data emphasize the existence of distinct subgroups of cholesteatomas identifiable at both cell kinetic and differentiation levels. Some of the biological variables used here to identify distinct biological subgroups of cholesteatomas in turn enabled some biological variables to be identified, so making it possible to classify the cholesteatomas in terms of recurrence versus nonrecurrence.

Immortalization of chinchilla middle ear epithelial cells by adenovirus 12-simian virus 40 hybrid virus

In order to study the cellular and molecular mechanisms of the pathogenesis of otitis media, a chinchilla middle ear epithelial cell line (CMEE-1) with differentiated cell characteristics was established by infection of a primary culture with the adenovirus 12-simian virus 40 (Ad12-SV40) hybrid. This cell line has been in continuous culture for 42 passages, whereas the parent cells underwent senescence and died at the 8th passage. The cell line also retains epithelial morphology and expresses cytokeratin polypeptides 4, 7, and 18, characteristic markers for epithelia. In Western blots of cell proteins, bands at 94 and 53 kd were labeled after binding antibodies against SV40 large T antigen and p53, respectively. Karyotype analysis showed that the cell line is derived from chinchilla epithelial cells. These findings confirm that the cell line is a chinchilla epithelial cell immortalized by the hybrid virus.

Apoptosis in meatal skin, cholesteatoma and squamous cell carcinoma of the ear

Apoptosis in normal meatal skin, cholesteatoma and squamous cell carcinoma (SCC) of the ear was investigated by using morphological analysis and in-situ specific labelling of fragmented DNA. In meatal skin, apoptotic cells were localized mainly in the granular layers, but were not so restricted in cholesteatoma, while in SCC they were even more dispersed. The apoptotic index (AI) was low (1.59 +/- 0.10 SEM) in normal skin. It was increased in cholesteatoma (2.09 +/- 0.11), and was intermediate in SCC (1.72 +/- 0.14). By contrast, the mitotic index (MI) increased from 0.19 +/- 0.02 in normal skin, to 0.25 +/- 0.01 in cholesteatoma and to 0.25 +/- 0.02 in SCC. Our findings indicate that apoptosis is involved in the epithelial homeostasis of meatal skin, cholesteatoma and SCC of the ear. The hyperproliferation of epithelial cells in cholesteatoma is counteracted by an increased apoptosis rate, while in SCC the increased cell proliferation without a compensatory increase in apoptosis may be associated with the malignant transformation.

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.

Culture of rabbit middle ear epithelial cells. A method for primary culture and subculture with identification, characterization and growth specification

During the last decade middle ear epithelium has been cultured from various species. Until now, subcultivation has been achieved only with the use of a feeder-cell layer or conditioned medium. These factors are possible confounders in the in vitro model. On the other hand, subcultivation is necessary for exact quantitative studies. We present a reproducible culture method allowing subcultivation without feeder-cells or conditioned medium. The main features in our method are a low-serum, hormone-supplemented medium, an incubation temperature of 34 degrees C, fixation of explants, gentle trypsinization and replating with high cell density. Cells were identified by immunohistochemistry through a battery of monclonal antibodies. The percentage of epithelial cells in the subculture was 99.2%. To our knowledge, this is the first report describing subcultivation of middle ear epithelial cells exclusively in a completely controlled environment. These are optimal circumstances for future investigation and quantification of various factors influencing proliferation and differentiation of middle ear epithelium.

Human-papillomavirus DNA in cholesteatomas

Cholesteatoma of the middle ear is a relatively common disorder, often with severe consequences. Histologically, the aggressively growing, bone-destructing form shows papillary growth and koilocytosis, which are characteristic of papillomavirus-induced lesions. A PCR (polymerase chain reaction) method using degenerate primers for the detection of any known or as yet unknown HPV (human papillomavirus) type was applied in screening 51 biopsies from 42 patients. A resulting 36% (16/45) of the cholesteatomas were found to contain papillomavirus DNA, which hybridized under stringent conditions with an HPV-II DNA probe. In 3 cases the presence of HPV-II DNA could be confirmed by sequencing the PCR products. The mere presence of this HPV DNA does not prove an etiological role of this group of viruses in the induction of cholesteatomas. It does, however, identify another group of human proliferative lesions putatively linked to papillomavirus infections.

Coexpression of cytokeratin and vimentin intermediate filaments in benign and malignant sweat gland tumors

The coexpression of cytokeratin and vimentin intermediate filaments has been immunohistochemically evaluated in 124 benign and malignant sweat gland tumors of various types in comparison to normal sweat glands. In addition, all neoplasms have been stained by an antibody to alpha-smooth muscle actin. Epithelial cells reacted with the pan-cytokeratin antibody lu-5. In normal sweat glands, vimentin immunoreactivity was restricted to myoepithelial cells and to some cells of the coiled duct. In benign sweat gland tumors (n = 88), coexpression of vimentin and alpha-smooth muscle actin was frequently found in basal cells of neoplasms considered to differentiate towards the secretory coil of the eccrine or apocrine gland. These included eccrine spiradenoma, apocrine cystadenoma, hidradenoma papilliferum, syringocystadenoma papilliferum, and cylindroma. Thus, in these tumors, vimentin-reactive cells corresponded to myoepithelial cells. Vimentin-positive cells were also found in 14 of 36 sweat gland carcinomas, including 1 case of sclerosing sweat duct carcinoma, 1 case of porocarcinoma, 4 cases of eccrine adenocarcinoma, 1 case of mucinous eccrine carcinoma, and 5 cases of apocrine adenocarcinoma. Co-expression of vimentin and alpha-smooth muscle actin was observed in some cells of eccrine and apocrine adenocarcinomas. Therefore, in these neoplasms, some vimentin-positive cells appear to represent myoepithelial cells. In contrast, vimentin-positive cells in all other malignant tumors did not express alpha-smooth muscle actin. Our results indicate that coexpression of cytokeratin and vimentin may be frequently found in a variety of benign and malignant sweat gland tumors. In the majority of these neoplasms, vimentin-positive cells correspond to myoepithelial cells. Because vimentin is not specific for myoepithelial cells, additional stains for alpha-smooth muscle actin should be performed to prove the myoepithelial nature of vimentin-positive cells.

Cytokeratin patterns of normal middle ear epithelia in humans, cats, and chinchillas

We describe the cytokeratin patterns of epithelia from the tympanic orifice, tympanic cavity, and mastoid cavity of humans, cats, and chinchillas, and compare these findings with those of tracheal epithelium and external canal epidermis. Our findings are as follows: 1) middle ear epithelium from all locations demonstrates some type of cytokeratin staining, 2) broad-spectrum cytokeratin antibodies stain epithelia of middle ear cleft, tracheal epithelium, and external canal epidermis in all species, 3) specific cytokeratin antibodies reveal species-related differences in middle ear and tracheal epithelia, 4) middle ear and tracheal epithelia usually have the same pattern, and 5) none of the monospecific cytokeratin antibodies have a positive reaction with external canal epidermis. These findings suggest that the cytokeratin patterns of middle ear epithelium are useful in studying the hyperplastic and metaplastic changes in otitis media; however, caution must be exercised when making interspecies comparisons.

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.

An immunohistochemical and histochemical study of cytokeratin, involucrin and transglutaminase in seborrhoeic keratosis

The mode of differentiation of seborrhoeic keratoses was investigated by immunohistochemical staining using cytokeratin (CK) polypeptide-specific monoclonal antibodies and an antibody specific for the particulate form of epidermal transglutaminase (ETgase), and by applying an anti-human involucrin serum. The role played by (E)Tgase was further evaluated using an activity assay based on the covalent attachment of monodansylcadaverine. Samples of uninvolved epidermis served as reference tissue. CK reactivities suggested that seborrhoeic keratoses is a hyperproliferative disease with an epidermal CK composition. CK5 and CK14 were prominent markers of basal and basaloid keratinocytes, whereas a decrease in staining occurred in advanced maturation stages and areas of terminal keratinization. In contrast, CK1 and CK10 were prominent markers of suprabasaloid differentiation stages and produced complementary stainings to those of CK5 and 14. Generally, CK10 staining was more impressive than CK1 staining and seemed to start before CK1 staining. In contrast to CK10 staining, cornified areas lost CK1 reactivity. These staining patterns were similar to those observed in uninvolved reference tissues. The epidermal CK subset was further supplemented with the 'hyperproliferative' CK6 and 16 which occur sequentially. Positive staining for CK6 was noted from basal and proximal basaloid cells onwards, whereas distal basaloid cells additionally showed CK16 staining. The presence of other non-epidermal CK polypeptides could not be shown. The competence for other differentiation markers belonging to the group of (E)Tgase and cornifying cell membranes also evolved with a typical epidermal pattern. (E)Tgase activity was restricted to advanced and terminal stages of keratinization and was dual in nature, i.e. a diffuse cytoplasmic staining occurred together with a prominent staining of cornifying cell membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Cytokeratin expression in normal and (pre)malignant head and neck epithelia: an overview

Intermediate filament proteins (IFPs) are important markers of tissue differentiation and have been receiving increasing interest, in particular, through their applicability in the characterization of malignant tumors. Cytokeratins (Cks) are a family of IFPs that are typically specific for epithelial cells. They are expressed in certain combinations depending on the type of epithelium and the degree of differentiation. This review presents a critical analysis of the available data on Ck expression in normal and (pre) neoplastic epithelia of the head and neck region. Special attention is paid to technical and cell biologic pitfalls, which can lead to false-negative or false-positive data. It appears that only a limited fraction of the reported data contributes substantially to our knowledge of IFP expression in head and neck cancer because of the use of ill-defined, often formalin-fixed and paraffin-embedded, tissue specimens, and the application of limited panels of monoclonal antibodies. It is concluded that the use of immunocytohistochemistry is promising for the differential diagnosis of head and neck tumors and contributes to our knowledge on their biologic behavior. However, documentations of more complete Ck expression patterns of normal and (pre)malignant epithelium are required, together with their correlation to clinical parameters.

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

Immunohistochemical investigations were carried out to determine the pattern of cytokeratin (CK) expression in middle ear cholesteatoma and related epithelia. Using monoclonal antibodies specific for CK chains and the indirect immunoperoxidase technique, we examined 10 CK polypeptides for expression. The external stratified squamous epithelium of the tympanic membrane generally expressed CKs 5, 10, and 14. In addition, basal keratinocytes in the annular region of the pars tensa expressed CK 19 (a simple epithelium marker), while suprabasally the hyperproliferative marker CK 16 was expressed. These data reflect the unusual proliferative nature of this region. The unexpected appearance of CK 16 (known to have a limited distribution in healthy epidermis) clearly relates to its expression in the neighboring deep meatus. The medial simple epithelium of the eardrum revealed mucosal CKs 7, 8, 14, 18, and 19. Acquired cholesteatoma lesions, besides CKs 5, 10, and 14, consistently expressed CK 16 in suprabasal layers. These results constitute the first direct molecular evidence for the hyperproliferative nature of the cholesteatoma matrix. Overall, our CK data suggest that aural cholesteatoma lesions and epidermal tissue in this area are related. However, they do not explain the mechanism(s) by which the eardrum or meatal epithelia might invade the middle ear cavity. Congenital cholesteatomas expressed CKs 5, 10, 14, and 16 equally. These CK data do not support the idea of a metaplastic origin from middle ear mucosa; instead, they suggest activation of an ectodermal rest in the middle ear cavity.

Cytokeratin expression in mucinous sweat gland carcinomas: an immunohistochemical analysis of four cases

Four mucinous sweat gland carcinomas were examined for the distribution of cytokeratin (CK) polypeptides using immunohistochemical techniques on paraffin-embedded sections. All the tumour specimens reacted with monoclonal antibodies to CK 7, CK 8, CK 18 and CK 19. Antibodies to CK 1, CK 1/2/10/14, CK 1/5/10/11, CK 13, CK 14 and CK 20 did not stain any of the carcinomas. The results add additional support to the notion that mucinous sweat gland carcinoma represents a tumour histogenetically related to the eccrine secretory coil. Furthermore, the absence of CK 20 might significantly contribute to the differentiation of this tumour from cutaneous metastases from gastrointestinal carcinomas.

Eccrine syringofibroadenoma: a case report with analysis of cytokeratin expression

A 56-year-old man presented with a 30-year history of a slowly enlarging lesion on the sole of his right foot. A biopsy showed an anastomosing network of small cuboidal cells with the formation of occasional sweat ductal lumina and a marked fibrovascular stroma. The histological findings were interpreted as consistent with the diagnosis of an eccrine syringofibroadenoma. Using immunohistochemistry all the tumour cells were positively stained by the pan-cytokeratin antibody Lu-5 and an antibody to the cytokeratins 1/5/10/11. In addition the luminal ductal cells expressed cytokeratin 19 and CEA. Tumour cells were negative for cytokeratins 1, 7, 8, 13 and 18 and did not express vimentin and GCDFP-15. The results indicate that the eccrine syringofibroadenoma is differentiated towards the dermal eccrine duct.

Patterns of cytokeratin expression in human gingival epithelia

Specimens of human gingiva were collected from teenage and adult subjects and frozen sections were stained with an extensive panel of monoclonal antibodies with defined specificities for individual cytokeratins. The results indicated different and distinctive patterns of keratin expression by the oral gingival, oral sulcular and the junctional epithelia. It was observed that epithelium with staining characteristics of sulcular epithelium extended over the gingival crest onto the oral surface of the gingiva. Junctional epithelium showed the unusual pattern of co-expression of keratins typical of the stratifying and of the simple epithelial phenotypes. The patterns of gingival keratin expression are compared with those of other mucosal epithelia. The findings are discussed in relation to mechanisms that may determine or influence the junctional epithelial phenotype.

Antikeratin 14 monoclonal antibody staining in psoriasis and seborrhoeic keratosis: immunofluorescence and two colour FACS studies

A monoclonal antibody (ES3A) was raised against a mouse graft-versus-host reaction (GVHR) model. This antibody was against basal cell cytoplasm and reacted with an acidic (pI 6.2) 50 kDa keratin of human epidermis. However, ES3A reacted with several lower layers of epidermal cells in psoriasis and seborrhoeic keratosis. Acanthotic seborrhoeic keratosis showed varying patterns even in a single lesion. If combined with FACS analysis, ES3A-positive cells could be quantified. Normal skin showed 28%, while psoriasis and seborrhoeic keratosis showed 44% and 51%, respectively. ES3A-positive compartments of the acanthotic type of seborrhoeic keratosis were larger than those of the hyperkeratotic type. ES3A may be suitable for quantification of germinative or proliferative cells.

The nature of the epithelium in acquired cholesteatoma

Monoclonal antibodies with defined specifications for individual cytokeratins were used to stain the epithelia of the external auditory meatus, the middle ear and cholesteatoma. The observed staining indicated that the epithelium of the external auditory meatus has a pattern of keratin expression typical of epidermis in general and the epithelium of the middle ear resembles simple columnar epithelia. The pattern of staining of cholesteatoma closely resembled that of the skin of the external auditory meatus.

An investigation of cytokeratin expression in skin epithelial cysts and some uncommon types of cystic tumours using chain-specific antibodies

The differentiation state of skin epithelial cysts and some uncommon types of epithelial skin tumours was investigated by immunohistochemical staining, mainly using cytokeratin (CK) polypeptide-specific monoclonal antibodies. Samples of interfollicular epidermis, hair follicles and eccrine sweat glands were included as reference tissues. The CK reactivity in epidermoid cysts and milia is not restricted to CKs involved in epidermal-type differentiation, i.e. CK1, 5, 10 and 14, but in addition CK16, a hyperproliferative keratinocyte marker is suprabasally expressed. CK1 and 10 are other prominent suprabasal markers, while CK14 seems to be preferentially expressed in the basal cell layer. Of the non-epidermal CKs, only CK4 was focally or more extensively detected in about 50% of the cases. In terms of CK reactivity, keratinization of trichilemmal cysts corresponds to the keratinization of the anagen-phase hair follicle in the isthmus. The CK reactivity is again restricted to CK1, 5, 10, 14 and 16. However, the CK1 as well as CK10 reactivity is subject to serious limitations, since both CKs were only convincingly observed in foci of terminal differentiation. Eccrine hydrocystoma obligatorily expresses a complex CK set, including CK7, 8, 14, 18 and 19. This CK set perfectly corresponds to the CK composition observed in acini of eccrine sweat glands. In addition, a discontinuous CK4 and 16 reactivity was seen in about 50% of the sites, while CK1 and 10 displayed a strictly focal appearance. On the other hand, syringoma produces in its distinct structures, a CK pattern reminiscent of the one observed in eccrine sweat gland ducts and includes CK1, 5, 10, 14, 16 and 19.(ABSTRACT TRUNCATED AT 250 WORDS)

Keratinization of middle ear cholesteatomas. I. A histochemical study of epidermal transglutaminase

A histochemical study was performed to determine the involvement of epidermal transglutaminase (ETgase) in the keratinization of middle ear cholesteatomatous lesions, and to compare it with its role in the middle ear mucosa and epidermis. In a first assay, we localized the (E)Tgase activity in situ. A second immunohistochemical assay revealed the distribution of the particulate form of ETgase, which is involved in cross-linked envelope formation. A remarkable difference between strongly keratinized epidermal tissues and the cholesteatoma matrix is the frequent observation in the latter of the remnants of (E)Tgase activity in cytosol, even in advanced stages of differentiation. As a consequence, the cell-membrane-associated ETgase activity, and thus the extent of cross-linking within the envelope, is at a lower level than expected. This aspect is reminiscent of the keratinization phenomenon manifested by thin epidermal tissues. In addition, our findings are the first to show that ETgase is a substantial marker of middle ear mucosa.

Keratinization of middle ear cholesteatomas. II. A histochemical study of epidermal transglutaminase substrates

A histochemical study was performed to clarify further the role played by epidermal transglutaminase (ETgase) in the keratinization of aural cholesteatoma. Weakly and strongly keratinized epidermal tissues and healthy middle ear mucosa were included as references. A first assay revealed the distribution of non-specified acyl donor substrates. In a second assay, the topography of involucrin was assessed immunohistochemically. In both epidermal and cholesteatoma matrix tissues, the presence of acyl donors was not restricted to the sites of (E)Tgase activity, but was almost uniformly extended throughout living layers. In reference tissues, residual acyl donors were poorly detected in horny layers, while they were more abundant in the stratum corneum of the cholesteatomas studied. The presence of involucrin along the cell membrane was observed at varying distances throughout the spinous and granular layers, depending upon the epidermal and matrix configurations. In thick epithelia, involucrin rapidly became concentrated at the cell periphery (in spinous keratinocytes), while in thin epithelia it was usually associated with cell flattening. This latter staining profile was observed more frequently in cholesteatomatous tissues. In addition, we regularly noticed an immediately suprabasal accumulation of involucrin, suggesting a locally hyperproliferative state of the matrix. An insufficient availability of acyl donors, especially involucrin, could not be used to explain the defective ETgase-mediated cross-linking of cholesteatoma cell membranes during terminal stages of differentiation. The present investigation may be the first to demonstrate the presence of involucrin in middle ear mucosa.

Expression of keratin 5 as a distinctive feature of epithelial and biphasic mesotheliomas. An immunohistochemical study using monoclonal antibody AE14

In previous biochemical analyses, keratin 5 (Mr 58,000) has been detected in most mesotheliomas with epithelial component but not in pulmonary adenocarcinomas (Blobel et al., Am J Pathol 121: 235-247, 1985). In the present study, we have characterized a monoclonal antibody, AE14, as being selectively specific for keratin 5 (apart from the reactivity with certain hair proteins) as shown by immunoblotting of gel-electrophoretically separated proteins from various tissues. Immunohistochemical screening of a variety of normal human tissues, using immunoperoxidase microscopy on cryostat sections, revealed the binding of this antibody to the basal, immature cells of stratified squamous epithelia, to basal cells of pseudostratified epithelia, to some myoepithelial cells, thymic reticulum cells, certain pancreatic duct cells, as well as a variable subpopulation of mesothelial cells of the pleura and the peritoneum. In 12/13 epithelial and biphasic mesotheliomas of the pleura, heterogeneous but extended staining with antibody AE14 was seen whereas 21 pulmonary adenocarcinomas were negative or, in six of these cases, showed staining of only a few cells. Among carcinomas from other sites, colonic adenocarcinomas and renal cell carcinomas were negative whereas limited staining was found in some pancreatic adenocarcinomas. It is suggested that antibody AE14 may be useful, as a defined polypeptide-specific reagent, in the histologic distinction between mesotheliomas and most adenocarcinomas. Furthermore, the expression patterns of keratin 5 as detected by antibody AE14 in various normal and malignant epithelial tissues are discussed, particularly their relation to processes of squamous metaplasia and their indication of phenotypic tumor heterogeneity.