Macula Flava and Vocal Fold Stellate Cells of the Human Adult Vocal Fold
Human adult maculae flavae are dense masses of cells and extracellular matrices located at the anterior and posterior ends of the membranous portion of the bilateral vocal folds.
Human maculae flavae are most likely involved in the metabolism of extracellular matrices essential for the viscoelasticity of the human vocal fold mucosa and are considered to be an important structure in the growth, development, and aging of the human vocal fold mucosa.
The extracellular matrices of human adult maculae flavae are composed of glycoproteins and glycosaminoglycans (hyaluronan) and fibrillar proteins such as collagen fibers, reticular fibers, and elastic fibers.
Vocal fold stellate cells contained in the human adult maculae flavae were discovered (Sato, Ann Otol Rhinol Laryngol 110: 319-25, 2001). They are stellate in shape and possess vitamin A-storing lipid droplets.
There are a number of morphological differences between vocal fold stellate cells and fibroblasts in the human vocal fold mucosa.
Along the surface of the vocal fold stellate cells, a number of vesicles are present and constantly synthesize extracellular matrices which are essential for the viscoelastic properties of the human vocal fold mucosa.
Vocal fold stellate cells possess cytoplasmic processes and are stellate in shape, desmin-positive cells with perinuclear vitamin A lipid droplets; therefore, the vocal fold stellate cells show the morphological features of hepatic stellate cells. These results are consistent with the concept that the vocal fold stellate cells are a member of the proposed diffuse stellate cell system.
Radiosensitivity of the vocal fold stellate cells is higher than that of fibroblasts, and radiation induces dysfunction of the vocal fold stellate cells.
As a result of the heterogeneity seen between vocal fold stellate cells and other interstitial cells, it is uncertain whether they derive from the same embryonic source as fibroblasts in the human vocal fold mucosa.
The vocal fold stellate cells in the maculae flavae form an independent cell category that should be considered a new category of cells in the human vocal fold mucosa.
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