Myology  2005 - Thursday, May 12th - Parallel symposia "Myoblast transfer and clinical applications"  

 

PROTOCOL OF AUTOLOGOUS MYOBLAST GRAFTS IN THE PHARYNGEAL MUSCLES TO CORRECT DYSPHAGIA IN PATIENTS WITH OCULO-PHARYNGEAL MUSCULAR DYSTROPHY  

 

Oculo-pharyngeal muscular dystrophy (OPMD), is characterized by the selective impairement of the upper esophageal sphincter (UES) and of the pharyngeal muscles resulting in dysphagia. The most common treatment for dysphagia is a UES myotomy which however does not prevent the progressive degradation of the pharyngeal muscles which sustain the pharyngeal propulsion.
A protocol of autologous myoblast grafts in the pharyngeal muscles has been initiated in June 2004 to correct dysphagia in patients with oculo pharyngeal muscular dystrophy, in accordance with the French legislation on ethical rules. Our aim is to improve both swallowing and the contractile deficit generated by the dystrophic pharyngeal muscles. This model of cellular therapy has been tested through a preclinical study performed in normal dogs, allowing the validation of the procedure and its safety, as well as to study the survival of the myoblasts grafted in the pharyngeal muscles.
The clinical trial includes patients who exhibited both signs of decreased pharyngeal propulsion and UES dysfunction. Biopsy of unaffected muscles (quadriceps and sterno-cleido-mastoid muscle) was performed to select the donor muscle. Then a sample of the chosen muscle was taken one month prior to the autotransplantation, and amplification of myoblasts was carried out in culture. The surgery consists in both a UES myotomy and injections of myoblasts above the site of myotomy, in the pharyngeal dystrophic muscles.
Results of the graft are evaluated by analysing the swallowing efficacy and the pharyngeal propulsion which is pre and post-operatively studied by videofluoroscopy swallowing study and videofiberoscopy of swallowing, and also by a questionnaire and quantitative analysis, performed at one month post-surgery, and every six months during two following years. As for today, 6 patients have already been enrolled in the study and 4 of them underwent the complete grafting process. No adverse effect has been observed.
This protocol may both improve the long-term treatment of the swallowing disorders and decrease life-threatening complications induced by aspiration and weight loss, due to the decreased pharyngeal propulsion.