title: Does the human skeletal muscle harbor the murine equivalents of cardiac precursor cells?
abstract: The limited plasticity of adult muscle- or bone marrow- derived stem cells intended for cardiac regeneration impedes their conversion into cardiomyocytes. Since murine skeletal muscle was reported to harbor cardiac precursor cells, we assessed whether similar cells exist in man. Skeletal muscle biopsies obtained from 39 patients were sorted by flow cytometry which generated three populations (CD90+/CD34(-), CD34+/CD90(-), CD90(-)/CD34(-)) expressing similar levels of cardiac (Nkx2.5, cTn-T, cTn-I, Cx43) and skeletal muscle (Myf-5, MyoD, myogenin) mRNAs, as assessed by quantitative reverse transcriptase-PCR. However, compared to unpurified myoblasts, CD34+/CD90(-) cells expressed greater amounts of endothelium-specific mRNAs and were, therefore, selected for transplantation experiments. Thirty immunosuppressed rats then underwent coronary artery ligation and, 4 weeks later, were intramyocardially injected with culture medium, myoblasts, or CD34+/CD90(-) cells. After 1 month, left ventricular ejection fraction was significantly higher in the CD34+/CD90(-) group than in the control and myoblast-injected hearts, which was associated with smaller fibrosis and greater angiogenesis. The low engraftment rate suggested a paracrine mechanism supported by the greater release of growth factors by CD34+/CD90(-) cells than by unsorted myoblasts. In conclusion, the human skeletal muscle does not harbor cardiac-specified cells but contains a CD34+ fraction endowed with an angiogenic potential providing superior functional and structural benefits.
authors.affiliation: INSERM U 633, Laboratory of Biosurgical Research, Hôpital Broussais, Paris, France.
authors.forename: Susanne
authors.initials: S
authors.lastname: Proksch
authors.forename: Alain
authors.initials: A
authors.lastname: Bel
authors.forename: Etienne
authors.initials: E
authors.lastname: Puymirat
authors.forename: Laetitia
authors.initials: L
authors.lastname: Pidial
authors.forename: Valérie
authors.initials: V
authors.lastname: Bellamy
authors.forename: Séverine
authors.initials: S
authors.lastname: Peyrard
authors.forename: Jérôme
authors.initials: J
authors.lastname: Larghero
authors.forename: Bernard
authors.initials: B
authors.lastname: Augereau-Vacher
authors.forename: Philippe
authors.initials: P
authors.lastname: Menasché
mesh_terms: D000818:Animals; D003470:Culture Media; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology*; D009206:Myocardium / Q000737:chemistry*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000276:immunology
chemical_list: D003470:Culture Media