Hypothesis:
Otosclerosis is an inflammatory bone remodeling disorder of the human otic capsule, which might be characterized by variable levels and unique expression pattern of TNF-α receptors.
Background:
Histologic characteristics of otosclerosis have been well described during the latest decades; however, the grading of different histopathologic and clinical stages has not been attributed precisely to the molecular biology of the pathologically increased metabolism of osteoclast-osteoblast axis.
Methods:
Forty otosclerotic- and 40 nonotosclerotic ankylotic stapes footplates (n = 80; men, 29; women, 51) were histologically analyzed: conventional hematoxylin-eosin staining and tumor necrosis factor-α receptor I and II (TNFRI/II)-specific immunofluorescent assay was performed.
Results:
Active otosclerosis (Grades I-II; n = 24) was featured by increased expression of TNFRII and moderate expression of TNFRI; inactive cases (Grades III-IV) were characterized by permanent expression of TNFRI; however, TNFRII-specific immunoreaction was absent. Nonotosclerotic stapes specimens showed a negligible TNFR expression. Tumor necrosis factor receptor expression pattern showed a strong correlation with the histologic activity of otosclerosis (χ2 test; p < 0.001).
Conclusion:
Detection of elevated TNFR expression demonstrates activated osteoclast metabolism and inflammatory pathways in otosclerosis. Different etiopathogenesis of otosclerotic and nonotosclerotic stapes ankylosis should be distinguished. Administration of monoclonal anti-TNF-α antibody may be a reasonable option in the medical treatment of active stages of otosclerosis.
