Optimization of autologous muscle stem cell survival in the denervated hemilarynx.
OBJECTIVE
Current treatments for vocal fold paralysis are suboptimal in that they fail to restore dynamic function. Autologous muscle stem cell (MSC) therapy is a promising potential therapy for vocal fold paralysis in that it can attenuate denervation-induced muscle atrophy and provide a vehicle for delivery of neurotrophic factors, thereby potentially selectively guiding reinnervation. The goal of this project was to characterize optimal conditions for injected autologous MSC survival in the thyroarytenoid (TA) muscle following recurrent laryngeal nerve (RLN) injury by local administration of adjuvant factors.


METHODS
Animal experiment.


METHODS
Unilateral RLN transection and sternocleidomastoid muscle (approximately 1 g) biopsies were performed in 20 male Wistar rats. One month later, 10 autologous MSCs labeled via retroviral-enhanced green fluorescent protein (EGFP) transduction were injected into the denervated hemilarynx of each animal with one of four adjuvant therapies: cardiotoxin [(CTX) 10 M], insulin-like growth factor-1 [(IGF- 1) 100 microg/mL], ciliary neurotrophic factor [(CNTF) 50 microg/mL], or saline. Animals were euthanized 1 month later and larynges harvested, sectioned, and analyzed for MSC survival.


RESULTS
All specimens demonstrate extensive MSC survival, with fusion of the MSCs with the denervated myofibers. Based on mean fluorescent intensity of the laryngeal specimens, IGF-1 and CNTF had the greatest positive influence on MSC survival. Myofiber diameters demonstrated myofiber atrophy to be inversely related to MSC survival, with the least atrophy in the groups having the greatest MSC survival.


CONCLUSIONS
Autologous MSC therapy may be a future treatment for vocal fold paralysis. These findings support a model whereby MSCs genetically engineered to secrete CNTF and/or IGF-1 may not only promote neural regeneration, but also enhance MSC survival in an autocrine fashion.
Halum
Stacey L
SL
Department of Otolaryngology-Head and Neck Surgery, Indiana University, 950 West Walnut Street, Indianapolis, Indiana 46202, USA. shalum@iupui.edu
Hiatt
Kelly K
KK
Naidu
Moumita
M
Sufyan
Ahmed S
AS
Clapp
D Wade
DW
D000818:Animals; D001706:Biopsy; D002470:Cell Survival / Q000502:physiology*; D007821:Laryngeal Muscles / Q000166:cytology* / Q000473:pathology; D008856:Microscopy, Fluorescence; D009121:Muscle Denervation; D018482:Muscle, Skeletal / Q000166:cytology*; D009133:Muscular Atrophy / Q000473:pathology; D032446:Myoblasts / Q000473:pathology; D009416:Nerve Regeneration / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012009:Recurrent Laryngeal Nerve / Q000473:pathology; D061226:Recurrent Laryngeal Nerve Injuries; D033581:Stem Cell Transplantation; D014182:Transplantation, Autologous; D014826:Vocal Cord Paralysis / Q000473:pathology*