Age-Related Changes in Vitamin A-Storing Stellate Cells of Human Vocal Folds

Abstract

Light and electron microscopic investigation of age-related changes in vocal fold stellate cells (VFSCs) of the human vocal fold mucosa was carried out on 10 excised human adult larynges from autopsy and surgical cases. The results are summarized as follows. Aged VFSCs were stellate in shape and possessed slender cytoplasmic processes. Aged VFSCs also possessed lipid droplets in the cytoplasm and stored vitamin A. Basically, the morphological characteristics of the aged VFSCs were the same as those of younger adults. The number of VFSCs had decreased. There were fewer intercellular organelles than in younger adults. Some components of the cytoplasm had degenerated. The nuclei of the VFSCs were dense and cleaved. There were few vesicles at the periphery of the cytoplasm of aged VFSCs, and few newly released amorphous materials. Some aged VFSCs had degenerated, and an accumulation of glycogen particles was seen in the cytoplasm. The number of fibers synthesized by these inactivated cells had decreased. These findings were recognized to various degrees. The aged VFSCs in the maculae flavae appear to have decreased activity, have abnormal metabolism, and undergo degeneration. Age-related changes in the VFSCs of the maculae flavae are postulated to influence the metabolism of extracellular matrices in the vocal fold mucosa, as well as the viscoelasticity of the aged vocal fold mucosa, and are one of the causes of aging of the voice.