Expression of PTHrP and RANKL in acquired middle ear cholesteatoma epithelium

Abstract

Background: Regarded as the most important clinical characteristic of middle ear cholesteatoma, the exact mechanism of bone resorption in cholesteatoma still remains unknown.

Objectives: To investigate protein expression of PTHrP and RANKL in acquired middle ear cholesteatoma epithelium and analyze their functional roles in the etiopathogenesis of bone resorption in middle ear cholesteatoma.

Material and methods: A total of 22 patients who underwent surgical treatment for middle ear cholesteatoma were recruited in the study. Protein expression of PTHrP and RANKL in middle ear cholesteatoma and normal postauricular skin was investigated by immunohistochemical staining. Correlations between bone resorption degree and expression of PTHrP and RANKL were also analyzed.

Results: Protein expression of PTHrP and RANKL in cholesteatoma epithelium significantly increased when compared with normal postauricular skin epithelium. In cholesteatoma epithelium, a significantly positive association was observed between PTHrP and RANKL expression. Meanwhile, obviously positive correlations between protein expression of PTHrP and RANKL and bone resorption degree were discovered.

Conclusions and significance: The increased protein expression of PTHrP and RANKL in cholesteatoma epithelium, and their associations with the degree of bone resorption, revealing that PTHrP might promote bone resorption process in middle ear cholesteatoma through RANKL signaling pathway.

Chinese abstract

背景：中耳胆脂瘤骨吸收是中耳胆脂瘤最重要的临床特征, 但其确切机制尚不清楚。

目的：研究获得性中耳胆脂瘤上皮中PTHrP和RANKL的蛋白表达, 分析其在中耳胆脂瘤骨吸收发病中的作用。

材料与方法：该研究包括22例接受过手术治疗的中耳胆脂瘤患者。采用免疫组化方法检测中耳胆脂瘤组织和正常耳后皮肤组织中PTHrP和RANKL的蛋白表达。分析骨吸收程度与PTHrP、RANKL表达的相关性。

结果：胆脂瘤上皮PTHrP和RANKL蛋白表达较正常耳后皮肤上皮明显高。在胆脂瘤上皮中, PTHrP与RANKL表达呈显著正相关。同时, PTHrP和RANKL蛋白表达与骨吸收程度呈显著正相关。

结论及意义：PTHrP和RANKL蛋白表达在胆脂瘤上皮细胞中增加, 并与骨吸收程度相关, 提示PTHrP可能通过RANKL信号途径促进中耳胆脂瘤骨吸收的过程。

Keywords:

• Cholesteatoma
• bone resorption
• PTHrP
• RANKL

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the Natural Science Foundation of Hunan Province under [Grant number 2019JJ50967], Natural Science Foundation of Hunan Province under [Grant number 2017JJ3441].