Gene therapy for muscle wasting conditions shows promise

Research published in the journal Science Translational Medicine last week shows gene therapy can improve muscle size and strength in monkeys. The technique holds promise as a therapy for several neuromuscular disorders, and researchers hope that clinical trials will start next year.

Researchers at Nationwide Children's Hospital, Columbus, US injected a virus containing a gene for follistatin protein directly into the thighs of monkeys. Follistatin protein inhibits the action of myostatin, a protein that inhibits muscle growth. The gene therapy resulted in long lasting increases in muscle size and strength in the monkeys, with no negative side effects.

Previously the gene therapy had been successfully tested in mice, and together with the new findings in monkeys, the team are hopeful that the technique could be used to improve muscle mass of people with neuromuscular disorders, such as muscular dystrophy.

'Our studies indicate that this relatively non-invasive approach could have long-term effects, involve few risks and could potentially be effective in various types of degenerative muscle disorders including multiple forms of muscular dystrophy', said the study's lead author, Dr Brian Kaspar.

The therapy would not be a cure for inherited conditions such as Duchenne muscular dystrophy (DMD), but it could limit the impact of disease and allow patients to retain the ability to walk for much longer.

'If we can improve the strength of muscles we can make a difference to the lives of these patients', said Professor Jerry Mendell, a specialist in muscle disease at Ohio State University and co-author of the study.

There may be other hurdles to overcome, as patients may need to take immunosuppressant drugs alongside the gene therapy. It will also have to be established that increasing muscle size is effective in treating diseases such as DMD, which affect muscle quality.

Marita Pohlschmidt, director of research at the Muscular Dystrophy Campaign, said: 'If proven to be safe and efficient, reducing the activity of myostatin could potentially be used to increase muscle strength for people with a broad range of neuromuscular conditions', adding 'these results, shown in healthy monkeys, are encouraging and represent another step forward in taking this therapeutic approach to clinical trial'.