Stellate Cells in the Human Child Vocal Fold Macula Flava

Objectives: Vitamin A-storing vocal fold stellate cells (SCs) in the macula flava (MF) are hypothesized to be involved in the metabolism of extracellular matrices (EM) of the human vocal fold mucosa (VFM). The SCs in the child VFM were examined. Study Design: Histologic analysis of cadaveric human child VFM. Methods: Light and electron microscopic investigations of SCs in the human child VFM were carried out on three excised human child larynges. Results: The SCs were stellate and dense in the child ME They had cytoplasmic processes, possessed lipid droplets, and stored vitamin A in their cytoplasm. The SCs had a small nucleus-cytoplasm ratio and rough endoplasmic reticula, suggesting constant protein synthesis in these cells. There were vesicles along the periphery of the cytoplasm, and newly released amorphous materials were seen on the cell surface. There were dense reticular, collagenous, and elastic fibers around SCs. The SCs exhibited strong cytoplasm staining with periodic acid-Schiff stain and type III collagen. Most of the VFSCs showed CD44 (a cell surface receptor for hyaluronic acid) expression, and a large amount of hyaluronic acid was present immediately adjacent to SCs. This study revealed several morphologic differences between the SCs in the MF and the conventional fibroblasts in the VFM. Conclusions: The SCs in the child MF constantly synthesized EM, essential for viscoelastic properties of the lamina propria of the human VFM, in the stage of vocal fold growth and development. The SCs in the MF were inferred to be involved in the growth and development of human VFM.