However, a UK expert says key differences between the way mice and humans deal with fat in the bloodstream could be a long way off.

The new therapy used a gene which is key in making a beneficial form of cholesterol called HDL.

When this was injected into mice who had been fed a bad diet of saturated fat, the hardening of the arteries, which eventually blocks the vessel and leads to heart attacks and strokes, was reversed.

Dr Daniel Rader, who led the study, said that therapies which raised the level of "good" cholesterol, rather than tried to cut the amount of harmful cholesterol, or LDL, were new avenue for treatments.

'Tremendous interest'

He said: "There has been tremendous interest in raising HDL cholesterol levels, not only as a way to prevent heart disease, but also to help shrink the existing blockages in blood vessels.

However, british expert Professor Anthony Winder, from the Royal Free Hospital in north London, said that while this was a significant study, the differences between mouse and human make-up meant it would be difficult to translate the results into treatments.

"The priority for humans is to get the bad cholesterol, or LDL, down, not to raise the levels of the good cholesterol.

"This is a good start but there is a very very different relationship between the way fats are carried in the bloodsteam of mice, and the way they are carried in humans.

"This is the main problem that has to be overcome."