Pendant le Congrès Myologie 2005, le Dr Tremblay a présenté le jeudi 12 mai 2005, lors du  symposium parallèle "Transfert de myoblastes et applications cliniques" une communication dont le titre est : "Restauration de l'expression de dystrophine dans les fibres musculaires de patients DMD à l'aide d'un immunosuppresseur".

 

 

RESTORATION OF DYSTROPHIN EXPRESSION IN THE MUSCLE FIBERS OF DUCHENNE MUSCULAR DYSTROPHY PATIENTS IMMUNOSUPPRESSED WITH TACROLIMUS.

Introduction : Our preliminary experiments in mice and monkeys have permitted us to obtain the approval of Health Canada to conduct a new phase 1 clinical trial of myoblast transplantation in DMD patients.
Objectives : The aim of the trial was to verify whether myoblast transplantation in patients immunosuppressed with tacrolimus would permit to restore the expression of dystrophin in the muscle fibers.
Methods : Thirty million myoblasts were injected in 1 cm3 of the Tibialis anterior muscle of 10 patients using either 25 or 100 parallel injections.
The contralateral side was injected with saline. The patients were immunosuppressed with tacrolimus. A muscle biopsy of the area injected with myoblasts was done a month later.
Results : The dystrophin mRNA was detected by RT-PCR in the muscle biopsy of all patients. Moreover, dystrophin expression was detected by immunohistochemistry in 3.5 to 50% of the muscle fibers. In most of the patients it was possible to confirm that the dystrophin was of donor origin by using mAbs which were specific for an epitope coded by an exon deleted in the patient genome. No antibodies against the donor myoblasts and myotubes were detected in the serum of the patients. There were, however, in some patients, higher lymphocyte infiltrations in the muscle injected with the donor myoblasts than in the muscle injected with saline.
Conclusion : The transplantation of myoblasts in DMD patients under an adequate immunosuppression and using a good delivery strategy has led to the expression of dystrophin in the muscle fibers of the DMD patients. This isthe first clinical trial of myoblast transplantation that has reach this objective.