PROJECT SUMMARY Vocal fold paralysis (VFP) is a major etiology of voice, swallowing, and airway disorders. Common causes of VFP include extra-laryngeal neoplasm, iatrogenic injury, neurologic disorder, endotracheal intubation, and other types of trauma. Idiopathic VFP (with no clear cause) is also common, constituting roughly 1/3 of VFP cases. Voice restoration options for these patients are suboptimal, and there are no minimally invasive permanent treatment options to restore vocal fold mobility and function. As a result, many patients are left with permanent voice loss and communication impairment. This application introduces a novel approach for restoring vocal fold muscle volume and function for the treatment of VFP. Results may lead to novel, minimally invasive options for voice restoration in these patients. The overall goal of the application is to use an adult stem cell based therapy (a modified muscle progenitor cell) to treat VFP. When clinically translated these cells can be derived from a given patient, and then injected into that patient's paralyzed vocal fold as a permanent treatment, potentially restoring both motion and function. We are currently doing preclinical testing of such a model in a large animal. Thus, these specific aims have the overall goal of developing cellular reinnervation therapy, which, after injection in an animal model, demonstrates: i) muscle augmentation with minimal loss of volume over time ii) minimal to no foreign body reaction and iii) robust, selective reinnervation of the denervated laryngeal muscle. Findings from the proposed studies should overcome the hurdles of current FDA approved laryngeal injectables—those hurdles being complete resorption of biomaterial over time, foreign body reactions resulting in granulomatous reaction/scarring, and lack of therapeutic reinnervation benefit (beyond a bulking effect). Because these studies are being done now in a large animal (porcine) model, with laryngeal size and function very similar to that of humans, findings will be highly translational. Results from these experiments should lead to landmark clinical innovations that will be relevant to both voice restoration and treatment of other peripheral nerve injuries.