Transplantation of adult myoblasts or adipose tissue precursor cells by high-density injection failed to improve reinnervated skeletal muscles.

We previously showed that transfer of adult myoblasts (MB) into cardiotoxin-damaged muscle improved the properties of reinnervated tibialis anterior muscle of rabbits. However, this cell therapy protocol cannot be applied to humans because of the hazardous effects of the myotoxin. To circumvent this approach, we used the recently developed high-density injection technique to autotransplant cultured cells 1 mm from each other into the tibialis anterior muscle without previous cardiotoxin-induced damage. Two months after transection and immediate suture of the common peroneal nerve, we transferred by this technique two types of precursor cells, MB or cells isolated from the adipose tissue stromal vascular fraction. In contrast to our previous results, muscles studied at 4 months showed no benefits in terms of function or morphology, whatever the transferred cells. These results, together with the results of earlier studies, emphasize the importance of delivery methods and the muscle environment in supporting cell integration into host tissues.