The role of middle ear effusions and epidermal growth factor in cholesteatoma formation in the gerbilline temporal bone

Dose- and starting time-dependent effect of the application of EGF to the regeneration of traumatic eardrum

Background: Some studies have shown that topical application of epidermal growth factor (EGF) accelerates healing in traumatic tympanic membrane perforations (TMPs), however, the optimal dose and starting time of application have not been established.Objectives: To determine the optimal dose and starting time of application of EGF for the regeneration of TMPs.Methods and materials: Patients with traumatic TMPs were first randomly assigned to low-dose EGF, high-dose EGF, and spontaneous healing groups. Then, the same patients were retrospectively analyzed at 6 months based on the starting time of treatment. The closure times, closure rates, and hearing gain were compared among the groups at 6 months.Results: The mean closure time was 10.20 ± 5.13 days in the low-dosage EGF group, 14.39 ± 6.20 days in the high-dosage EGF group, and 33.17 ± 16.37 days in the spontaneous healing group; the difference was significant (p < .001).Conclusions: Daily application of EGF shortened the closure time of traumatic TMPs compared with those that healed spontaneously. However, high-dose EGF instead prolonged the closure time compared to low-dose EGF.

Expression of disintegrin and metalloproteinase family proteins 10, 12 and 17 in cholesteatoma

Objective:

Proteases of the disintegrin and metalloproteinase family (also known as ADAM proteins) are involved in various physiological and pathological processes. This study assessed the expression of disintegrin and metalloproteinase family proteins 10, 12 and 17 in cholesteatoma.

Materials and methods:

The study evaluated cholesteatoma specimens from 19 patients, and external ear canal skin samples from 7 of the same patients (as controls), for the expression of disintegrin and metalloproteinase family proteins 10, 12 and 17, using immunohistochemical methods.

Results and analysis:

The study observed over-expression of proteins 10 and 17 in blood vessels, and over-expression of proteins 12 and 17 in cholesteatoma stroma. Immunostaining scores for proteins 10, 12 and 17 in epithelial and inflammatory cells from cholesteatoma specimens versus control specimens showed no statistically significant differences.

Conclusion:

Over-expression of disintegrin and metalloproteinase family proteins 10, 12 and 17 in cholesteatoma may be related to cholesteatoma pathogenesis. These proteins deserve further study as they may represent potential targets for cholesteatoma treatment.