Duchenne muscular dystrophy

There was a very interesting talk today on new advances in the treatment of a genetic disease called Duchenne Muscular Dystrophy. DMD is an x-linked progressive muscular dystrophy which affects around one boy in every 3,000. The disease is caused by a defect in a muscle protein called dystrophin, which is important in maintaining the structural integrity of muscle fibres. Without functional dystrophin, muscles are unable to contract properly, and suffer progressive damage. By the age of twelve, boys with DMD are wheelchair bound. They usually die in their twenties from respiratory or cardiac failure.

One way to treat DMD is to try and inject DNA encoding for normal (i.e. functional) dystrophin into muscles. This can be done by giving modified plasmids. However, the problem then remains is how do you deliver dystrophin to all the muscles in the body? There’s no way you could inject the plasmids into each muscle individually. What the speaker was investigating was the use of microbubble technology to aid uptake. Plasmids were injected along with microbubbles, and then ultrasound was applied to pop all the bubbles. This would have the effect of transiently disrupting muscle cell membranes to facilitate entry of the plasmid into the muscle. Preliminary studies on a murine model seem promising, and show significant expression of functional dystrophin for up to three months following the procedure. There’s still a long long way to go before we can think of applying this to humans though. How, for example, would we apply the ultrasound to the whole body? Is that even safe? What about tissue heating?

Do let me know what you think.

Moc