Untersuchungen zu Veränderungen der extrazellulären Matrix beim Reinke-Ödem

Abstract

Reinke's edema is a benign, pathological change in the vocal folds. The disease manifests itself through a loss of function of the vocal fold mechanics, accompanied by a deterioration in the quality of the voice through to loss of voice or dyspnea. The disease occurs almost exclusively in middle-aged women. The main predisposing factors are long-term tobacco consumption, high stress on the voice and oesophageal reflux. Laryngoscopically, a broad, bead-like, edematous swelling of the vocal fold mucosa can be observed, the histological characterization of which was the aim of this work. Histologically, there are various changes in the extracellular matrix of the vocal fold tissue compared to other pathologies of the vocal fold, which is shown in the present work. In contrast to other diseases of the vocal cord, Reinke's edema shows a clear accumulation of hyaluronic acid in the lamina propria. However, neither an isolated increased gene expression of the synthesizing hyaluron synthases-1, -2 and -3 nor an isolated decreased gene expression of the degrading hyaluronidases-1 and -2 could be determined in Reinke's edema, but only an increased turnover of hyaluronic acid. The collagen and elastic fibers clearly lost their structure in Reinke's edema. The formation of the edema in the lamina propria resulted in a destruction of the fine networks of the respective fibers. An increased number of vessels in the lamina propria in Reinke's edema could not be shown, but the vessels had a significantly enlarged lumen compared to the benign changes in the vocal folds that were not associated with Reinke's edema. In addition to the extracellular matrix, the epithelial cover layer including the basement membrane of the lamina propria was also examined using a light microscope. A much wider basement membrane could be seen in Reinke's edema. In contrast, the epithelial cover layer was rather slightly changed and showed a reduced number of cell layers compared to the other pathologies. The genesis of benign vocal fold diseases is as good as elucidated based on known risk factors. Using the available investigations, histological differences, especially in the extracellular matrix, between Reinke's edema and other diseases of the vocal folds could be identified. However, there was no clear causal relationship with regard to possible risk factors and the changes in the extracellular matrix, especially hyaluronic acid, in Reinke's edema. This should be researched and clarified in further studies; The matrix metalloproteinase deserves particular mention here, which is believed to be able to maintain or restore the physiological structure of the vocal folds through active repair and remodeling mechanisms.