Utilisation de facteurs motogéniques afin d'améliorer le succès de la thérapie cellulaire pour le traitement de la dystrophie musculaire de Duchenne

Authors: Lafrenière, Jean-François
Advisor: Tremblay, Jacques-P.
Abstract: Due to the absence of dystrophin, muscle fibers of Duchenne Muscular Dystrophy (DMD) patients are fragile and their constant ruptures induce a progressive lost of muscular tissues. Myoblast transplantation (MT) is an experimental treatment for DMD. Following their intramuscular injection, healthy myogenic precursor cells are able to fuse with host fibers and restore dystrophin expression. Although MT had efficiently restore dystrophin expression in DMD patients; transplantation success following a single injection is limited. The low dispersion of dystrophin expressing fibers is a major problem that requires myoblast injections every millimetre to obtain an optimal graft success. Since poor transplanted cell migration outside the injection sites has been proposed to explain the restriction of hybrid myofibers, motogenic factors were tested to verify whether their co-injection with transplanted myoblasts is a physiological and effective approach to stimulate proteolytic activity as well as myoblast intramuscular migration. Results demonstrated that insulin growth factor-1, basic fibroblast growth factor and interleukin-4 show strong chemokinetic potential for human skeletal myoblasts and increase the migration distances reached by transplanted cells. By improving cell migration through muscular tissue, we hoped that growth factors co-injection would help transplanted cells to fuse with myofibers located outside the injection sites. However, experiments conducted in monkeys suggest that improvement of transplanted cell migration is not, per se, a sufficient approach to increase the quantity and dispersion of hybrid fibers. Generally, our work helped to clarify and redefine a major problem, which limits graft success. Even if short-term observations suggest that transplanted cells are not always trapped inside the injection sites, myofibers including grafted cell nuclei remain restricted to the injection trajectories one month post transplantation. Lack of fusion with undamaged myofibers located outside the injection sites will probably have to be resolved to improve dispersion of hybrid myofibers and thus reduce the number of injections required for the treatment of DMD patients. As long as this fusion problem remains, all approaches, which increase transplanted cell migration, will not be sufficient to increase MT success.
Document Type: Thèse de doctorat
Issue Date: 2007
Open Access Date: 13 April 2018
Permalink: http://hdl.handle.net/20.500.11794/19740
Grantor: Université Laval
Collection:Thèses et mémoires

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