Adult stem cells harvested from human patients with the muscle wasting disease Duchene Muscular Dystrophy (DMD) can be genetically corrected and used to improve muscle strength in mice with DMD, according to a study published in the journal Cell Stem Cell last week. The researchers, based at the University of Milan, heralded the new gene therapy as a step towards being able to treat DMD patients with their own cells, thus avoiding the tissue rejection risks associated with foreign tissue transplants.
DMD is a muscle-wasting disease that causes a steady deterioration of muscles and often results in death before the age of 30. The condition, which is usually inherited and incurable, affects 1 in 3500 male newborn boys. The disease is caused by an inherited fault in the gene that encodes the body's instructions for making dystrophin - a crucial muscle protein.
The research team isolated so-called 'progenitor' muscle cells - a type of adult stem cell that can grow into functioning muscle cells - from human DMD patients and injected them into mice to show that the mice displayed DMD-like symptoms. They then rescued the mice by again injecting them with progenitor muscle cells from the same patients, which had been genetically modified to make them ignore the mutation, producing a shortened but functioning version of the dystrophin protein.
Within three weeks the researchers saw marked improvements in the mice, including increased dystrophin levels in muscle fibres and increased muscle strength, as demonstrated by comparing the mice running on a treadmill before and after treatment and by lab tests carried out on leg muscles removed from the mice. 'Use of the patient's own cells would reduce the risk of implant rejection seen with transplantation of normal muscle-forming cells', explains Dr Yvan Torrente, who led the study.
Although genetic modification and muscle transplant techniques used in this study have both been tried before, this is the first time they have been studied in unison, note Kay Davis, Oxford University, and Miranda Grounds, University of Western Australia, in an accompanying review article.