Compositions comprising preconditioned myoblasts having enhanced fusion properties

Abstract

The present invention relates to a method for preconditioning healthy donor's myoblasts in vitro before transplantation thereof in compatible patients suffering of recessive myopathies, particularly of muscular dystrophy. This in vitro preconditioning improves the success of the transplantation while not requiring an in vivo preconditioning of the patient's muscle by irradiation or by administering muscular toxin. The invention further relates to compositions comprising such preconditioned myoblasts.

What is claimed:  
     
         1 . A composition comprising a muscle-fusion promoting amount of trophic factors, including basic fibroblast growth factor (bFGF) together with a suitable carrier.  
     
     
         2 . The composition of    claim 2   , wherein said basic fibroblast growth factor is added exogenously to said culture of myoblasts.  
     
     
         3 . The composition of    claim 1    wherein said basic fibroblast growth factor is provided endogenously by said myoblasts, which express a muscle-fusion enhancing segment or variant thereof of basic fibroblast growth factor.  
     
     
         4 . The composition of    claim 1   , wherein said basic fibroblast growth factor is human basic fibroblast growth factor.  
     
     
         5 . The composition of    claim 2   , wherein said basic fibroblast growth factor is human basic fibroblast growth factor.  
     
     
         6 . The composition of    claim 3   , wherein said basic fibroblast growth factor is human basic fibroblast growth factor.  
     
     
         7 . The composition of    claim 3   , wherein said endogenously expressed basic fibroblast growth factor, is expressed from a retroviral vector stably integrated inside the genome of said myoblasts.  
     
     
         8 . A method of improving the fusion of myoblasts upon transplantation thereof into muscular tissue of a recipient individual, comprising growing said myoblasts in culture, wherein said myoblasts have been genetically engineered to express a muscle-fusion enhancing portion of basic fibroblast growth factor.