Stem cells could one day be used to help regenerate wasted muscle in patients with muscular dystrophy.
The research was carried out on mice
Tests in mice have shown that a type of stem cells found in blood vessels could help people with a particular form of muscular dystrophy called limb-girdle muscular dystrophy.
The Italian researchers say that although much more research is needed before the findings can be applied to humans, it provides a new focus for muscular dystrophy research.
Muscular Dystrophy (MD) is a collection of disorders caused by genetic defects that lead to increasing muscle weakness over time. There is currently no cure.
The researchers found stem cells called mesoangioblasts, can cross from the bloodstream into muscle tissue.
The researchers suggest the stem cells could be collected from a patient's blood vessels, and genetically "corrected" in the laboratory.
They would then be allowed to multiply, and injected back into the patient's bloodstream.
It is hoped they would then migrate to the patient's muscles, and begin producing healthy muscle cells.
Because they would be from the patient's own body, their immune system would not reject them.
When the therapy was given to mice, it was found that the treated muscles contained larger and more numerous and apparently normal muscle fibres.
The treated animals were also able to walk on a rotating wheel for longer than untreated animals, although not for as long as healthy mice.
But the researchers stress there are several hurdles to overcome before the therapy can be used in humans.
The mesoangioblasts were only discovered in foetal blood vessels around a year ago, and much more needs to be known about how they work in the body.
In addition, the "genetic correction" the scientists carried out, where a healthy version of a gene was inserted into the stem cell, was effective in mice, but could raise safety concerns in humans.
Dr Giulio Cossu, of the Stem Cell Research Institute in Milan, who led the research, said: "Although these results are exciting, we have not cured the mice.
"We believe this is a significant step toward therapy, but the question that
keeps me awake at night is whether this will work in larger animals."
"I'm convinced this is an important result, but this is still not the therapy - for the mice or for patients."
Jenny Versnel, head of research at the UK's Muscular Dystrophy Campaign, said: "We welcome any scientific advances which bring us closer to finding effective treatments or cures for muscular dystrophy."
The research is published in the magazine Science.