Lamina propria replacement therapy with cultured autologous fibroblasts for vocal fold scars

Abstract

Objectives: To develop a canine model of vocal fold scar and to evaluate its treatment with lamina propria replacement therapy using autologous cultured fibroblasts.

Materials and methods: Full thickness of the lamina propria layer in canine vocal folds was injured with a laser. Fibroblasts were cultured and expanded in the laboratory from a buccal mucosal biopsy. The scarred vocal folds were treated with 3 weekly injections of fourth, fifth, and sixth passage autologous fibroblasts. Mucosal waves and acoustic parameters were measured at baseline, after scarification, and several months after injection therapy. Histologic evaluation of the vocal folds for fibroblasts, collagen, elastin, reticulin, and hyaluronic acid was performed.

Results: Nine beagle dogs were used, and 1 animal served as control. Vocal fold scarring resulted in absent or severely limited mucosal waves and significantly worse acoustic parameters. Significant improvements in mucosal waves and acoustic parameters were obtained after lamina propria replacement therapy. After therapy, mucosal waves became normal in 4 animals and near normal in the other 4. No statistical difference was found in mucosal waves between baseline and post-therapy. All animals tolerated therapy without complications. The treated vocal folds demonstrated an increased density of fibroblasts, collagen, and reticulin, a decreased density of elastin, and no change in hyaluronic acid.

Conclusions and significance: Therapeutic options for vocal fold scars are limited. Lamina propria replacement therapy in the form of autologous cultured fibroblasts improves mucosal pliability and returns normal or near normal mucosal waves in experimentally scarred vocal folds. This novel therapeutic modality may hold new promise for treating vocal fold scars.