Angiogene Faktoren in der Fibroblastenzellkultur des Gehörgangcholesteatoms

Reexamination of Etiology and Surgical Outcome in Patient With Advanced External Auditory Canal Cholesteatoma

OBJECTIVE

To describe the etiology of advanced cases of external auditory canal (EAC) cholesteatoma (EACC), and to report the surgical management and outcomes based on canalplasty depending on the extent of adjacent structures involvement around the EAC.

STUDY DESIGN

Retrospective case review.

SETTING

University hospital.

PATIENTS

Participants comprised 28 patients (12 males, 16 females) ranging in age from 9 to 86 years old. All patients presented with advanced-stage EACC (Naim's classification: stage III/IV).

INTERVENTION

Surgery ranged from simple bony meatoplasty with cartilage graft repair to more enlarged EAC canalplasty combined with tympanoplasty.

RESULT

EACC was categorized as idiopathic in 22 patients and secondary EACC in six patients. Six patients with idiopathic EACC were receiving hemodialysis, one of whom showed bilateral pathology. Particularly in cases with epithelial invasion into the hypotympanum immediately adjacent to the jugular bulb, multi-layered repair including bone paste, post-auricular pedicled musculo-periosteal flap, auto cartilage, and temporalis muscle fascia were required. Five patients required revision surgery (17%), including one case of recurrent (reconstructed) cholesteatoma and three cases of perforation of the tympanic membrane.

CONCLUSION

In the majority of our series, underlying diseases followed with microangiopathy and angiogenesis could be possible candidates in the etiology of EACC. Enlarged bony meatoplasty and multilayered reconstruction surgery brought about self-cleaning and dried the EAC in advanced-stage EACC.

Modeling the Cholesteatoma Microenvironment: Coculture of HaCaT Keratinocytes With WS1 Fibroblasts Induces MMP-2 Activation, Invasive Phenotype, and Proteolysis of the Extracellular Matrix

BACKGROUND

Increased keratinocyte proliferation, increased keratinocyte migration, elaboration of proteases resulting in proteolysis of the extracellular matrix (ECM), and destruction of surrounding tissues all typify the course of cholesteatoma growth. The contribution of stromal fibroblasts to these behaviors remains relatively unexplored.

OBJECTIVES

Our objective for the current studies was to create a simple model with which to study these cholesteatoma behaviors, specifically, cell migration, invasion, and proteolysis of the extracellular matrix as well as the role of fibroblasts in the activated keratinocyte phenotype of cholesteatoma.

DESIGN

The authors conducted an in vitro culture model.

METHODS

The resulting model consists of activated keratinocytes (HaCaT cells) cocultured with normal dermal fibroblasts (WS1 cells) within a three-dimensional reconstituted ECM. We used a confocal imaging assay and software analysis to quantify total functional proteolysis of the ECM in monotypic and organotypic cocultures. This was accomplished by growing cells on an artificial ECM comprised of Matrigel and DQ-collagen IV. DQ-collagen is a "quenched" fluorescent peptide whose fluorescence is unmasked by proteolytic cleavage.

RESULTS

Organotypic cocultures of keratinocytes and fibroblasts exhibited increased cell migration, increased cell invasion, increased matrix metalloproteinase-2 secretion and activation, and increased proteolysis of type IV collagen in three-dimensional ECM. Exposure to NSC27366, inhibitor of the small GTPase, Rac, resulted in reduction in both cell invasion and ECM proteolysis.

CONCLUSIONS

Stromal fibroblasts may stimulate the invasive phenotype of keratinocytes, including ECM proteolysis. Increased cell invasion and proteolysis are dependent on the Rac pathway in this model. This simple culture model may help further our understanding of these destructive behaviors in cholesteatoma keratinocytes.