In the recent article “Remyelination of chronic demyelinated lesions with directly induced neural stem cells” published in Brain (2025), Dr. Luca Peruzzotti-Jametti, Dr. Stefano Pluchino, and colleagues from the University of Cambridge and international collaborators explore a novel stem cell-based strategy for repairing nerve damage in multiple sclerosis (MS). The study addresses a key challenge in progressive MS: the failure to repair myelin, which is the protective sheath around nerve fibers, once it's been damaged.
MS is a debilitating neurological disease that affects over 2.8 million people worldwide. In the early stages of MS, the body can sometimes repair lost myelin, but over time, especially in progressive forms of the disease and as patients age, this natural repair process becomes less effective. As a result, nerve fibers are left exposed and vulnerable, leading to permanent damage and worsening disability. Our current disease modifying therapies are excellent at decreasing new lesions and relapses, but do not restore lost myelin or reverse nerve damage.
This study investigates whether a new type of stem cell, called induced neural stem cells (iNSCs), created by reprogramming skin cells, can help repair demyelinated areas of the spinal cord in mice. The researchers transplanted both mouse and human derived iNSCs into mice with experimentally induced spinal cord lesions that mimic aspects of MS. The results were highly promising. The iNSCs successfully survived, integrated into the damaged tissue, and developed into mature oligodendrocytes, the cells responsible for producing myelin. The grafted cells not only directly created new myelin, but they also stimulated the body's own repair mechanisms by encouraging existing progenitor (or early-stage) cells to mature into myelin-producing cells. Additionally, the transplants helped reduce harmful inflammation in the lesion areas, creating a more favorable environment for healing. To test the therapy in a more severe setting, the team used genetically modified mice that lack the ability to form new oligodendrocytes. Even in these challenging conditions, transplanted iNSCs produced myelin and promoted repair, showing that the stem cells can act independently of the body’s natural repair system.
Importantly, the investigator evaluated the safety and behavior of human iNSCs in the same model. These human cells survived for up to six months after transplantation, formed human myelin, and showed no signs of forming tumors or causing harm, an encouraging sign for potential clinical use.
This research is a meaningful step forward for people with MS, particularly those with progressive disease for whom treatment options remain limited. The idea that a patient’s own skin cells could one day be converted into stem cells to repair nerve damage is a powerful and exciting concept in regenerative medicine.
However, it is very important to remember that this work is still in its early stages and was conducted entirely in animals. Much more research is needed to confirm the long-term safety, optimize cell delivery, and determine whether similar effects would occur in humans. Clinical trials are a necessary next step, and the path to a viable therapy will require time and careful testing.
Nevertheless, the findings provide strong early evidence that directly induced neural stem cells could become a transformative tool for restoring function in MS and other demyelinating diseases.