Abstract
Objectives/Hypothesis:
Keratinocytes harvested from acquired cholesteatoma and grown in cell culture will demonstrate increased interleukin‐8 (IL‐8) production in response to tumor necrosis factor (TNF)‐alpha as compared with a control keratinocyte cell line. Immunohistochemical studies have identified IL‐8 and TNF‐alpha, mediators of bony destruction, in tissue samples of cholesteatoma. TNF‐alpha stimulates IL‐8 production in healthy epidermal keratinocyte cell lines. It is not known whether TNF‐alpha stimulates IL‐8 production in cultured cholesteatoma keratinocytes.
Study Design:
Prospective controlled tissue culture experiment.
Methods:
Tissue from an acquired cholesteatoma was dissociated and grown in keratinocyte serum‐free media for 8 weeks. Cholesteatoma keratinocytes and a control cell line of skin epidermal keratinocytes were treated with TNF‐alpha. Conditioned media were harvested; production of IL‐8 was measured by enzyme‐linked immunosorbent assay, and cell counts were performed.
Results:
At a zero concentration of TNF‐alpha, mean production of IL‐8 by cholesteatoma keratinocytes was 39,809 pg/mL/24hr/1 × 10^6^ cells versus 1,907 pg/mL/24hr/1 × 10^6^ cells from skin epidermal keratinocytes, a statistically significant difference (P
< .05). The cholesteatoma keratinocytes showed a 2.1‐fold increase in response to 2 pg/mL of TNF‐alpha and a 2.44‐fold increase in response to 20 pg/mL of TNF‐alpha. The skin epidermal keratinocyte cell line demonstrated a 1.07‐ and 1.13‐fold increase to respective concentrations of TNF‐alpha.
Conclusions:
Cholesteatoma keratinocytes appear to retain cell signaling characteristics in vitro that distinguish them from skin epidermal keratinocytes. This finding may indicate that cholesteatoma keratinocytes undergo a change in behavior in vivo that is preserved after the cells are removed from the inflammatory environment of the middle ear.