Gene therapy in the news

Gene therapy has been used for the first time to relieve some of the effects of muscular dystrophy. The effects of the condition, a severe inherited muscle-wasting disease, were partially corrected in mice when a new gene was introduced that restored levels of dystrophin, a protein lacked by sufferers, to the muscles.

The researchers, from the Seattle base of the University of Washington, US, injected a modified cold virus carrying the gene into the hind legs of mice with a condition similar to Duchenne muscular dystrophy. After a month, the mice were seen to have a 40 per cent improvement in muscle action. The research is published in the Proceedings of the National Academy of Sciences.

In addition, researchers in Finland have found that gene therapy may help to prevent arteries becoming blocked again after surgical procedures to clear them. When angioplasty - the insertion of a balloon-like catheter into an artery to unblock it - is performed, a metal tube called a stent is sometimes used to prop the artery open. This can trigger a reaction in some patients which causes the artery to rapidly re-block.

Now, the researchers, from the University of Kuoppio in Finland, believe they have discovered why this happens. They believe the stent can damage the lining of the artery walls, triggering the rapid growth of new cells which contribute to the re-blocking of the artery. Damage also causes 'distress signals' to be sent out, which cause the body to produce chemicals called 'free radicals', which in turn cause more damage to the lining. They also believe the free radicals can be counteracted by the insertion of an extra gene which will cause another chemical to be produced, but which is not produced naturally by patients. The theory was tested in a rabbit model, using a modified virus to deliver the gene. After two and four weeks, it was observed that fewer free radicals were present in the rabbits' arteries.