Huibert F van Waegeningh1, Fenna A Ebbens2, Erik van Spronsen2, Roelof-Jan Oostra3. 1. Department of Otorhinolaryngology, Amsterdam University Medical Centers, Meibergdreef 9, 1105AZ Amsterdam, Noord-Holland, the Netherlands. Electronic address: huibvanwaegeningh@gmail.com. 2. Department of Otorhinolaryngology, Amsterdam University Medical Centers, Meibergdreef 9, 1105AZ Amsterdam, Noord-Holland, the Netherlands. 3. Department of Anatomy, Embryology and Physiology, Amsterdam University Medical Centers, Meibergdreef 9, 1105AZ Amsterdam, Noord-Holland, the Netherlands.
Abstract
OBJECTIVE: The epithelium lining the human middle ear and adjacent temporal bone cavity shows a varying morphological appearance throughout these cavities. Its embryologic origin has long been debated and recently got attention in a newly proposed theory of a dual embryologic origin. The epithelial morphology and its differentiating capabilities are of significance in future mucosa-targeted therapeutic agents and could affect surgical approaches of the temporal bone. This study aims to analyze reported murine histological findings that led to the theory of a dual epithelial embryological origin and immunohistochemically investigate whether such an epithelial embryological origin in the human fetal middle ear could be true. METHODS: By combining a sagittal sectioning technique and immuno-histochemical staining, a comprehensive immuno-histological overview of the fetal human middle ear during a critical stage of tympanic cavitation was provided. A critical analysis of previously reported findings leading to the theory of a dual epithelial embryological origin and a comparison of these findings to the findings in the human fetal middle ear was performed. RESULTS: The reported findings and critical analysis provide multiple arguments for an entirely endodermal embryonic origin of the epithelium lining the tympanic cavity. CONCLUSION: Different morphological epithelial appearances throughout the tympanic and temporal bone cavities could be explained by different stages of epithelial differentiation rather than different embryologic origin and endodermal rupture does not seem to be a necessity for these cavities to form.
OBJECTIVE: The epithelium lining the human middle ear and adjacent temporal bone cavity shows a varying morphological appearance throughout these cavities. Its embryologic origin has long been debated and recently got attention in a newly proposed theory of a dual embryologic origin. The epithelial morphology and its differentiating capabilities are of significance in future mucosa-targeted therapeutic agents and could affect surgical approaches of the temporal bone. This study aims to analyze reported murine histological findings that led to the theory of a dual epithelial embryological origin and immunohistochemically investigate whether such an epithelial embryological origin in the human fetal middle ear could be true. METHODS: By combining a sagittal sectioning technique and immuno-histochemical staining, a comprehensive immuno-histological overview of the fetal human middle ear during a critical stage of tympanic cavitation was provided. A critical analysis of previously reported findings leading to the theory of a dual epithelial embryological origin and a comparison of these findings to the findings in the human fetal middle ear was performed. RESULTS: The reported findings and critical analysis provide multiple arguments for an entirely endodermal embryonic origin of the epithelium lining the tympanic cavity. CONCLUSION: Different morphological epithelial appearances throughout the tympanic and temporal bone cavities could be explained by different stages of epithelial differentiation rather than different embryologic origin and endodermal rupture does not seem to be a necessity for these cavities to form.