title: Losartan enhances the success of myoblast transplantation.
abstract: Duchenne muscular dystrophy is a recessive X-linked genetic disease caused by dystrophin gene mutations. Cell therapy can be a potential approach aiming to introduce a functional dystrophin in the dystrophic patient myofibers. However, this strategy produced so far limited results.  Transforming growth factor-β (TGF-β) is a negative regulator of skeletal muscle development and is responsible for limiting myogenic regeneration. The combination of TGF-β signaling inhibition with myoblast transplantation can be an effective therapeutic approach in dystrophin-deficient  patients. Our aim was to verify whether the success of human myoblast transplantation in immunodeficient dystrophic mice is enhanced with losartan, a molecule that downregulates TGF-β expression. In vitro, blocking TGF-β activity with losartan increased proliferation and fusion and  decreased apoptosis in human myoblasts. In vivo, human myoblasts were transplanted in mice treated with oral losartan. Immunodetection of human dystrophin in tibialis anterior cross sections 1 month posttransplantation revealed more human dystrophin-positive myofibers in these mice than in  nontreated dystrophic mice. Thus, blocking the TGF-β signal with losartan treatment improved the success of myoblast transplantation probably by increasing myoblast proliferation and fusion, decreasing macrophage activation, and changing the expression of myogenic regulator factors.
authors.affiliation: Unité de recherche de recherche en Génétique Humaine, Centre de recherche de CHUL, CHUQ, Faculté de médecine, Université Laval, Québec, QC, Canada.
authors.forename: Raouia
authors.initials: R
authors.lastname: Fakhfakh
authors.forename: Yann
authors.initials: Y
authors.lastname: Lamarre
authors.forename: Daniel
authors.initials: D
authors.lastname: Skuk
authors.forename: Jacques P
authors.initials: JP
authors.lastname: Tremblay
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002454:Cell Differentiation; D049109:Cell Proliferation / Q000187:drug effects; D017690:Cell Transplantation / Q000379:methods; D002478:Cells, Cultured; D016189:Dystrophin / Q000096:biosynthesis; D006085:Graft Survival; D006801:Humans; D019808:Losartan / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D009137:Muscular Dystrophy, Animal / Q000628:therapy*; D032446:Myoblasts / Q000166:cytology / Q000502:physiology / Q000637:transplantation*; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors*
chemical_list: D016189:Dystrophin; D016212:Transforming Growth Factor beta; D019808:Losartan