Age-related changes of the macula flava of the human vocal fold.

This investigation was carried out to determine the histologic structure and age-related changes of the macula flava of human aged vocal folds. Excised human adult senescent larynges served as the material for this study. Light microscopic and transmission electron microscopic observations were made. The results are summarized as follows. 1) The anterior and posterior maculae flavae were elliptical in shape and about 1.5 x 1.5 x 1 mm in size. 2) The macula flava was composed of fibroblasts, elastic fibers, collagenous fibers, and ground substance. 3) The number of fibroblasts decreased. 4) Components in the cytoplasm, such as Golgi apparatus and rough endoplasmic reticulum, were fewer than in younger adults. 5) Some fibroblasts and some components in the cytoplasm degenerated. 6) The accumulation of glycogen granules and lipid droplets were seen in the cytoplasm. 7) The number of collagenous and elastic fibers synthesized by the fibroblasts decreased. 8) These findings were evident to various degrees and suggested the reduction of fibroblast activation, abnormal metabolism, and degeneration. A decrease in the number and activation of fibroblasts in maculae flavae indicates decreased synthesis of fibrous components in the vocal fold mucosa. This in turn influences the viscoelasticity and stiffness of vibrating tissue and contributes partially to aging of the voice.