Dystrophy, further progress gene therapy and stem cells

The new technique developed by Italian team overcomes the obstacles to get there, in mice, the therapeutic gene. It improves the symptoms of the disease Alessio MANFREDI 
 
NEW step forward to fight muscular dystrophy: a particular gene therapy can overcome some obstacles, he allowed to ferry the therapeutic gene into muscle cells of mice suffering from the same form of muscular dystrophy. Was to develop a team of scientists led by Giulio Cossu and German Francis Xavier, and the San Raffaele University of Milan, who were able to improve symptoms in animals, thus opening new perspectives for combating the disease even in 'man. 

It 'very difficult to stop or reverse the progressive loss of muscle fibers in Duchenne dystrophy, a genetic disorder caused by mutation of a gene that is located on the X chromosome, which makes it impossible to produce in sick individuals dystrophin, an essential protein that makes up the scaffolding of muscle cells. 

For years, Italian researchers are struggling with this disease for which there is currently no cure. Many hopes are placed in gene therapy, in order to get the healthy gene of dystrophin in muscle of patients, but the road is not easy: the gene for dystrophin is simply too large to be carried by a simple viral vector, without consider that the gene vector and should be injected into the muscles of the body.

Now Cossu and colleagues, in a paper published in Science Translational Medicine, have found ways to circumvent the problem, beating a path new, able to carry a healthy copy of the dystrophin gene to the muscles directly without using a viral vector, combining, however, therapy with stem cells and a human artificial chromosome. 

"It 'a long that we focus on this research," says Professor Cossu. "About ten years ago we identified a particular type of stem cells normally associated with blood vessels, mesoangioblasts that, in studies conducted on two models of muscular dystrophy in mice and dogs, have been shown to be able to fuse with existing muscle fibers , producing dystrophin healthy and regenerating muscle tissue. So far, however, we were able to use only healthy cells from a donor, which implies the need for immunosuppression to prevent rejection of transplanted cells. " 

Thinking that these cells - which can overcome the barriers of blood vessels and may also differentiate into muscle fibers - could carry the gene replacement of dystrophin to the muscles of mice sick, the team, in collaboration with a Japanese group, has taken another step forward, creating an artificial chromosome vector to ferry the healthy gene. The carrier, with its cargo, was then transferred in mesoangioblasts, then injected into the muscles of dystrophic animals. 

The effects? "Significant," says the professor. "The symptoms of the disease in mice were attenuated and were produced functional muscle fibers, an improvement of the disease." If the results in mice are encouraging, "now the next step is to do in humans," says Cossu, "although several practical problems remain to be resolved, so it will take time."

Source repubblica.it