Regeneration of the Larynx

Abstract

The larynx is a complex organ consisting of cartilage, muscle, and vocal fold mucosa which has multi-functions including respiration, voice, and swallowing. Severe damage to the larynx deteriorates the quality of life, and requires a treatment strategy of tissue engineering and regenerative medicine. Basic and clinical researches on regeneration of the larynx have rapidly emerged since the beginning of the 21st century. Regeneration of the vocal fold for cases with vocal fold scarring and atrophy has received widespread attention. Basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF) have proven to have regenerative effects on the vocal fold by simulating production and deposition of hyaluronic acid (HA) in the lamina propria of the vocal fold, in mean time by modulating collagen turnover. Mesenchymal stem cells (MSC) derived from bone marrow or fat tissue have also shown great potential in regeneration of the vocal fold. Early-phase clinical trials using bFGF, HGF, and MSCs have been completed showing promising effects on vocal fold regeneration with no severe adverse events. Basic FGF has also proven to have regenerative effects on the degenerative vocalis muscle in paralyzed vocal folds. Large defects of the larynx, including cartilage through the mucosa in cases of hemilaryngectomy, were treated with implant of bio-scaffolds in animal studies, which revealed simultaneous regeneration of the complex tissues. Decellularization technology has enabled creation of a decellularized whole larynx which has no immune systems. Such bio-scaffold may be used for transplantation after total laryngectomy with no concern of immune rejection. More basic and clinical researches may achieve clinical translation for several severe diseases of the larynx.