Transplantation of myocyte precursors derived from embryonic stem cells transfected with IGFII gene in a mouse model of muscle injury.
BACKGROUND
Reconstruction of skeletal muscle tissue is hampered by the lack of availability of functional substitution of the tissue.


METHODS
Embryonic stem (ES) cells were transfected with the insulin-like growth factor (IGF) II gene and were selected with G418. The resultant cell clones were analyzed regarding their myogenic differentiation in vitro and in vivo.


RESULTS
The cells expressed early and late myogenic differentiation markers, including myoD, myogenin, and dystrophin in vitro. They had phosphorylated Akt within the cells, suggesting their activation by the secreted IGFII. Transplantation of the cells to injured anterior tibial muscle of mice significantly improved their motor functions compared to injured mice transplanted with undifferentiated ES cells and injured mice given vehicle alone. The transfected cells adapted to the injured muscle, formed myofibers positive for dystrophin and negative for MyoD and myogenin. Trichrome staining and toluidine blue staining support myofiber formation in vivo. The enzymatic activity of acetylcholine esterase suggested the functional activity of the regenerated motor units. The evoked electromyogram of anterior tibial muscle transplanted with the transfected cells showed significantly higher potentials compared to that transplanted with undifferentiated ES cells and that injected with phosphate-buffered saline (control injury). Electron microscopic examination confirmed the myofiber formation in the cells in vivo.


CONCLUSIONS
Transfection of IGFII gene into ES cells may be applicable for transplantation therapy of muscle damage due to injury and myopathies.
Kamochi
Hiromasa
H
Departments of Immunology and Medicine, St. Marianna University School of Medicine, Kawasaki, Japan.
Kurokawa
Manae S
MS
Yoshikawa
Hideshi
H
Ueda
Yuji
Y
Masuda
Chieko
C
Takada
Erika
E
Watanabe
Kenji
K
Sakakibara
Manabu
M
Natuki
Yasunori
Y
Kimura
Kenjiro
K
Beppu
Moroe
M
Aoki
Haruhito
H
Suzuki
Noboru
N
D000222:Adaptation, Physiological; D000818:Animals; D002454:Cell Differentiation; D004622:Embryo, Mammalian / Q000166:cytology*; D015316:Genetic Therapy; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D032342:Muscle Cells / Q000166:cytology*; D018482:Muscle, Skeletal / Q000293:injuries*; D012038:Regeneration; D033581:Stem Cell Transplantation; D014162:Transfection
D007335:Insulin-Like Growth Factor II