[Alterations of the basal membrane in middle ear cholesteatoma]

Matrix metalloproteinase 2: an important genetic marker for cholesteatomas

AIM

This study is to determine the MMP2s presence in cholesteatomas and whether complicating cholesteatomas show a higher immunohistochemical expression of matrix metalloproteinase 2. Cholesteatoma produces enzymes that cause bone erosion like matrix metalloproteinase 2 (MMP2).

MATERIAL AND METHODS

We analyzed the expression of MMP2 in invasive (causing complications) compared to latent cholesteatomas (not causing complications). A cross-sectional study with nineteen slides and paraffin blocks of cholesteatomas derived from mastoidectomies were located and processed, including 8 invasive and 11 latent cholesteatomas. Immunohistochemical technique was empregated to MMP2.

RESULTS

The results are expressed as 0, + (to low), ++ and +++(high) according to the quantity and color of the immunohistochemical staining of MMP2. Higher expression of MMP2 was observed in 7 (87.5%) of the 8 invasive cholesteatomas. With respect to latent cholesteatomas, higher expression of MMP2 was observed in 27.3% (3 cases), with Fishers exact test indicating a significant difference (p=0.015).

CONCLUSIONS

Cholesteatoamas express MMP2 and Invasive cholesteatomas had high MMP2 compared to latent cholesteatomas.

Terminal differentiation and mitogen-activated protein kinase signaling in human cholesteatoma epithelium

OBJECTIVES

To investigate whether--in cholesteatoma epithelium--terminal differentiation, resulting in high involucrin expression, is associated with mitogen-activated protein kinase (MAPK) signaling.

BACKGROUND

Alterations in specific signal transduction pathways may explain abnormal differentiation of the keratinocytes in cholesteatoma. Signaling pathways used by eukaryotic cells to transduce extracellular signals into cellular responses converge on activated mitogen-activated protein kinases, mainly extracellular signal-regulated kinase, c-Jun NH2-terminal kinase, and p38.

METHODS

Tissue samples were taken from 16 patients with acquired cholesteatoma. Histologic examination showed that 12 of the 16 cholesteatomas were inflamed. Immunohistochemical methods were used to determine expressions of involucrin and the activated form of p38, extracellular signal-regulated kinase, and c-Jun NH2-terminal kinase proteins. The results obtained from cholesteatoma tissue were compared with paired control samples from retroauricular skin.

RESULTS

We demonstrated increased levels of involucrin and increased levels of the activated forms of p38 and ERK1/2 in cholesteatoma epithelium when compared with control samples. No abnormality was found in the activation and expression of JNK1/2. A positive correlation was found between p38, pERK1/2, and involucrin expression (p<0.05).

CONCLUSION

Our results demonstrate that signaling via the mitogen-activated protein kinases ERK1/2 and p38 is increased in cholesteatoma epithelium when compared with control skin. The correlations between involucrin-and phosphorylated pERK1/2 expression and between involucrin-and phosphorylated p38 expression indicates that terminal differentiation in cholesteatoma epithelium proceeds via activation of these mitogen-activated protein kinase signaling pathways. We discussed whether this increased mitogen-activated protein kinase-driven terminal differentiation is probably part of a keratinocyte survival program or caused by an inflammation-induced cellular stress response.

Comparative analysis of the epithelium stroma interaction of acquired middle ear cholesteatoma in children and adults

In the clinical setting, pediatric cholesteatomas frequently behave more aggressively than similar lesions in adults. The reason for the difference in behavior is still unclear. The purpose of the present study was to investigate the cell to cell and epithelial-stroma interaction of acquired cholesteatoma in adults and children and search for differences on the cellular level, which might explain the different behavior of these lesions. Operative specimens of 54 patients [40 adults (average age of 39.7 years), 14 children (average age of 8.3 years)] who underwent primary surgery for an acquired cholesteatoma of the middle ear were examined by histopathology and DNA-image cytometry (DNA-ICM). Immunohistochemical investigations included expression of proliferation markers (proliferation cell nuclear antigen and MIB-1) along with cell surface markers reflecting the cell-to-cell interaction (i.e. alpha1beta6-integrin, E-cadherin, I-CAM = CD54), and the epithelial to stroma interaction (i.e. alphav and beta3 intergin chains, V-CAM = CD106, CD44v6 and fibronectin). Pediatric cholesteatomas demonstrated higher incidence of acute inflammation and more extensive disease relative to those from the adults. Indices of DNA-ICM, however, revealed normal diploid DNA content in both groups. Higher proliferation scores occurred in the pediatric group compared to adult cholesteatoma. Cell surface markers and cell adhesion molecules were equally expressed in both groups except alpha1beta6-integrin and fibronectin, which were over expressed in pediatric cholesteatomas. Statistically, however, these differences showed only a trend towards significance. According to the results of the present study, pediatric and adult cholesteatomas do not show any marked differences on the cellular level. Thus the observed clinical more aggressive behavior of pediatric cholesteatoma is likely due to other secondary factors such as more intense inflammation, disturbed middle ear ventilation or the diminished calcium salt content of pediatric bone.

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.

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.

Expression von Zell-Zell-Adhäsionsproteinen im Gehörgangscholesteatom

BACKGROUND

External auditory canal cholesteatoma (EACC) is a rare entity in otolaryngology, which is histomorphologically identical with middle ear cholesteatoma. The cause of EACCt is, however, still not clear. The aim of this study was to describe the expression of beta-catenin, MMP-2, and MMP-9 in EACC matrix compared to the normal auditory meatal skin (AMS).

METHODS

Thirteen specimens were obtained during surgical procedure. EACC and AMS specimens were immunostained with antibodies for beta-catenin, MMP-2, and MMP-9.

RESULTS

Only the basal layers of the EACC specimens were positive for beta-catenin. The suprabasal layers showed diminished or negative immunostaining for beta-catenin. In all layers, AMS was homogeneously positive for beta-catenin. In contrast, the immunostaining for the gelatinases was equally increased in all layers of EACC, whereas AMS was weekly positive.

CONCLUSION

The reduced immunoreactivity for beta-catenin may have been present because of the lessened cell-cell adhesion in the suprabasal layers of EACC. The increased expression of the metalloproteinases might point at an increased lack of integrity of EACC matrix. Recent studies revealed a balance between disintegrating and stabilising factors in normal tissue, which is disturbed in inflamed and neoplastic tissue. In EACC matrix, an imbalance of these factors, represented by reduced beta-catenin and increased gelatinase expression, is possible. Increased desquamation, the accumulation of keratin debris, and loss of tissue-stability support our findings.