Young blood treats old mice with MS
By transplanting cells from the blood of young mice, scientists have successfully stimulated stem cells to repair the damaged nerve tissue of old mice with multiple sclerosis. The experiments show that people with advanced stages of the disease could be treated by reactivating their own repair mechanisms.
Multiple sclerosis (MS) is a disease of the nervous system caused by the damage and loss of the myelin sheath – a fatty coat that surround nerve fibres. The disease can become progressively worse over many years as the patient gets older and becomes less able to repair or regenerate their myelin sheath. However, scientists were unsure of why this might be.
To investigate, the researchers produced MS-like damage to the spinal cords of anaesthetised old mice, creating small areas of myelin loss. They then exposed the areas to immune cells isolated from the blood of young mice. They found that some of these cells, called macrophages, cleared away the debris of damaged myelin and stimulated the old mice’s own stem cells to form new myelin sheath. This debris has previously been shown to impede myelin repair.
MS can be caused by the damage of the myelin sheath by the body’s own immune system. It is not clear why this happens but it suggests that faulty immune cells are at least partly responsible. This work shows that by transplanting immune cells from healthy young mice, the body can repair itself after the debris has been cleared.
These are exciting but early results. Much more work is needed to understand the causes of myelin damage in MS patients, but this work offers the possibility that therapies could be developed in the future that stimulate the patient’s own stem cells to repair the damage.
Please see the AnimalResearch.info page on multiple sclerosis for background.