Donor cell type Primary location Muscle regeneration1 Ex vivo expansion with regenerative potential2 Contribution to Stem cell pool3 Immunogenicity4 Systemic delivery References Bone marrow derived stem cells bone marrow yes no yes phenotypic unknown yes [78] iPS cells skin (fibroblasts) yes yes yes phenotypic unknown no [74] Meschenchymal Stem Cell (MSC) all organs yes yes at least 15 passages no unknown Yes [79] Muscle CD133+ve cells muscle interstitium/circulation Yes limited (blood-derived), extensive (muscle-derived) yes phenotypic unknown yes [80,81] Muscle SP cells muscle interstitium Yes not tested yes functional (reinjury) low not studied [82] Muscle-Derived Stem Cells Unknown Yes yes, MDSC were tested at passage 10-12 yes phenotypic low no [83] Myoblasts myofiber Yes easy to culture, loss of regenerative potential yes (probably SC subpopulation) high no [4] Myoendothelial cells blood vessels Yes yes with regenerative potential no evidence unknown no [84] PICs (PW1+ve cells) muscle interstitium yes not tested yes (phenotypic) Unknown not studied [71] Satellite Cells sublamina yes no loss of regenerative potential yes functional (serial transplantation) low no [5,7] Vessel-associated cells blood vessels muscle yes early passages were tested yes phenotypic low yes [72,85] 1=Contribution to muscle regeneration after transplantation is scored 2=Scored positive (‘yes’) if the studies report regeneration potential in vivo following extensive ex vivo expansion. In most cases freshly isolated cells were evaluated 3=Scored positive when functional (e.g. serial transplantations or reinjury experiments) or phenotypic contribution to the stem cell pool was reported. Contribution was scored as ‘phenotypic’ only if study report localization to the SC niche with/without expression of Pax7 4=Immunogenicity was considered low, when cells engrafted muscle of immunocompetent hosts

Table 2: Regenerative properties of muscle regenerative cells. The table depicts different types of muscle regenerative cells, most of which are resident to skeletal muscle. Each types of muscle regenerative cell is scored according to the five requirements of the optimal candidate for stem cell therapy (see text).