We evaluated myoblast implantation in 10 boys with Duchenne muscular d
ystrophy (DMD) and absent dystrophin (age 5-10 years) who were implant
ed with 100 million myoblasts in the anterior tibial muscle of one leg
and placebo in the other. Cyclosporine (5 mg/kg/day) was administered
for 7 months. Pre- and postimplantation (after 1 and 6 months) muscle
biopsies were analyzed. Force generation (tetanic tension and maximum
voluntary contraction) was measured monthly in a double-blind design.
There was increased force generation in both legs of all boys, probab
ly due to cyclosporine. Using the polymerase chain reaction, evidence
of myoblast survival and dystrophin mRNA expression was obtained in 3
patients after 1 month and in 1 patient after 6 months. These studies
suggest a salutary effect of cyclosporine upon muscular force generati
on in Duchenne muscular dystrophy; however, myoblast implantation was
not effective in replacing clinically significant amounts of dystrophi
n in DMD muscle. (C) 1997 John Wiley & Sons, Inc.