SYDNEY, Australia - Researchers at the Victor Chang Cardiac Research Institute here said they have cleared the way for a genetic treatment that will make ordinary muscle a better substitute for heart muscle.

Announced recently in the scientific journal Nature, the breakthrough involves the growth factor IGF-1 (insulin-like growth factor-1), which helps repair cellular wear and tear in ordinary skeleton muscle.

Head of the project research team, Robert Graham, said his team has successfully inserted the gene that codes for IGF-1 into muscle cells, both in culture and in tissue, and identified the pathways the growth factor used within the cell.

With the improved knowledge of the workings of the growth factor, the team now is looking at genetic treatments to improve muscles, but clearing the remaining hurdles may require another two years of work. Besides improving muscle mass in the elderly - making them less prone to falls and broken bones - a genetic treatment also may help improve the procedure in which a muscle is removed from the back of a patient with a defective heart, then wrapped around the heart and stimulated to act as an auxiliary heart muscle. - Mark Lawson