Recent Advances in Skeletal Muscle Stem Cells for Duchenne Muscular Dystrophy Treatment

About 50 years ago, the satellite cell was discovered through electron microscopic inspection of skeletal muscle. Satellite cells are mono-nucleated and located in the edge of the skeletal myofibers. These cells were imposed for their association with muscle regeneration. Satellite cells maintain dormant state in the mature muscle and are activated mitotically during muscle injuries, and finally differentiated to myoblasts. It contributes to the myofibrils resulting in muscle recovery from the injury [1]. Collins proved that satellite cells have both differentiation and self-renewal ability [2]. Sequentially, Kuang et al. established that the muscle stem cells achieve self-renewal through asymmetrical divisions. Also, satellite cells did not consist of only adult stem cells, rather both adult stem cells and committed progenitor cells [3]. Muscular dystrophies include many diseases, which have skeletal muscle wasting and limit mobility of patients. Among that, Duchenne muscular dystrophy (DMD), fragility of respiratory muscles and absence of dystrophin protein in the cardiac muscle results in respiratory or cardiac failure and early death [4]. The underlying pathogenesis is already investigated, but the treatment has not been established yet. However, research has accumulated these days and clinical trials are also being performed now. There are roughly four methods to research DMD treatments, 1) gene therapy replacing the mutated gene, 2) cell therapy which replace affected cells or using bone marrow-derived stem cells and mesoangioblasts, 3) repairing the endogenous gene using exon skipping, skipping premature termination, and 4) drug therapy which compensates for lack of dystrophin, promotes function in dystrophic muscle, improves muscle hypertrophy and minimizes muscle wasting, uses histone deacetylase inhibitors or NO-releasing anti-inflammatory drugs [5]. In this article, cell therapies in DMD are focused in a review and current clinical trials using cell therapy are introduced. Hanyang Med Rev 2015;35:222-228 http://dx.doi.org/10.7599/hmr.2015.35.4.222 pISSN 1738-429X eISSN 2234-4446