Fibroblasts in human vocal fold mucosa

Area of Science:

• Laryngology
• Cell Biology
• Connective Tissue Research

Background:

• Vocal fold structure is crucial for phonation.
• Fibroblasts are key cells in vocal fold connective tissue.
• Distinct regions within the vocal fold mucosa, macula flava (MF) and Reinke's space (RS), have unique cellular compositions.

Purpose of the Study:

• To investigate and compare the ultrastructural characteristics of fibroblasts in the macula flava and Reinke's space of human vocal folds.
• To differentiate fibroblast activity in these regions across different age groups (newborn vs. adult).

Main Methods:

• Transmission electron microscopy (TEM) was utilized.
• Autopsy-obtained larynges from five adult and five newborn individuals were analyzed.
• Fibroblast morphology, nucleus-to-cytoplasm ratio, and organelle development (rough endoplasmic reticulum, Golgi apparatus) were assessed.

Main Results:

• Macula flava fibroblasts (adults and newborns) exhibited a stellate shape, small nucleus/cytoplasm ratio, and well-developed rough endoplasmic reticulum and Golgi apparatus, indicating active fiber production.
• Reinke's space fibroblasts were oval (newborns) or spindle-shaped (adults) with a large nucleus/cytoplasm ratio and less developed organelles, suggesting lower synthetic activity.
• MF fibroblasts actively produced collagenous and elastic fibers.

Conclusions:

• Fibroblasts in the macula flava contribute to vocal ligament development (infants) and metabolism (adults).
• Reinke's space fibroblasts are largely inactive but can be activated in response to vocal fold injury.
• These findings highlight regional and age-dependent specialization of fibroblasts within the vocal fold mucosa.