Role of macrophages in bone destruction in cholesteatoma otitis media

许多研究报道，典型的破骨细胞在人乳腺脂肪瘤活检中并不常见。我们以前报道过在胆脂瘤基质下的上皮下组织中发现了许多巨噬细胞。因此，我们假设巨噬细胞具有破骨细胞样细胞的活性。在患者知情同意的情况下，鼓室成形术中取出胆脂瘤基质、上皮下肉芽组织和基质附近的小骨标本。结果如下：1) CD68抗体免疫组化染色上皮下结缔组织多核细胞。2)通过免疫组织化学和原位杂交，在巨噬细胞中观察到通常在破骨细胞中表达的Cathepsin K和TRAP（酒石酸抗性酸性磷酸酶）。3) RT-PCR也识别出Cathepsin K和TRAP。4)利用免疫组化和原位杂交技术，在巨噬细胞中观察到破骨细胞表面必需的OPN （osteopontin）。5)培养液中表达了胆脂瘤基质和肉芽组织细胞因子（IL-1、IL-6、TNF-a、M-SCP）。这些发现表明，炎症细胞因子诱导巨噬细胞从骨髓到上皮下结缔组织，并成为破骨细胞样巨噬细胞附着在骨表面。

Many studies reported that the typical osteoclasts are infrequent in human chlesteatoma biopsies. We previously reported that many macrophages were found in subepithelial tissue under cholesteatoma matrix. Therefore, we hypothesized that the macrophage has an activity of the osteoclast-like cell. Under informed consent to the patients, cholesteatoma matrix, subepithelial granulation tissue and ossicles adjacent to matrix were taken out for specimens during tympanoplasty.Results were the followings ; 1) many multinuclear cells were stained in subepithelial connective tissue with immunohistochemistry of CD68 antibody. 2) Cathepsin K and TRAP (tartrate-resistant acid phosphatase), which are usually expressed in osteoclasts, were observed in macrophages with immunohistochemistry and in situ hybridization. 3) Cathepsin K and TRAP were also recognized by RT-PCR. 4) OPN (osteopontin), which is necessary to attach to the surface of osteoclasts, was observed in macrophages with immunohistochemistry and in situ hybridization. 5) Cytokines of cholesteatoma matrix and granulation tissue (IL-1, IL-6, TNF-a, M-SCP) were expressed in the culture liquid.These findings suggested that inflammatory cytokines induced macrophages from the bone marrow to subepithelial connective tissue and that they became osteoclast-like macrophages to attach to the bone surface.