Stem cell transplants for multiple sclerosis (MS) represent a promising but complex area of research aimed at slowing disease progression, repairing neurological damage, and potentially resetting the immune system to prevent further attacks on the nervous system. MS is a chronic autoimmune disease where the immune system mistakenly attacks the protective myelin sheath covering nerve fibers in the brain and spinal cord, leading to inflammation, demyelination, and neurodegeneration. This results in symptoms such as vision loss, muscle weakness, coordination problems, sensory changes, cognitive difficulties, and other disabilities.
There are two main types of stem cell approaches being explored for MS treatment: hematopoietic stem cell transplantation (HSCT) and mesenchymal stem cell (MSC) therapy. Each has distinct mechanisms, goals, and challenges.
**Hematopoietic Stem Cell Transplantation (HSCT)** involves collecting a patient’s own blood-forming stem cells, then using high-dose chemotherapy or immunosuppressive drugs to wipe out the existing immune system. After this, the collected stem cells are reinfused to regenerate a new immune system. The rationale is that this “immune reset” can stop the immune system from attacking myelin and nerve tissue. This approach is mostly studied in patients with aggressive, treatment-resistant relapsing-remitting MS (RRMS). Clinical trials comparing HSCT to the best available therapies have shown that HSCT can significantly reduce disease activity and disability progression in some patients. However, it carries risks due to the intense immunosuppression, including infections and other complications, so it is generally reserved for severe cases. Long-term follow-up is ongoing to better understand its durability and safety profile.
**Mesenchymal Stem Cell (MSC) Therapy** uses stem cells derived from sources like bone marrow or adipose tissue that have immunomodulatory and neuroprotective properties. MSCs can influence the immune system to reduce inflammation and may promote repair of damaged nerve tissue by supporting remyelination and neuroregeneration. Research indicates that MSC therapy can slow disease progression and improve neurological function in MS patients, with some studies reporting reduced lesion activity on MRI and improved disability scores. MSCs also secrete anti-inflammatory molecules and growth factors that may help protect neurons and encourage repair.
However, MSCs from MS patients themselves may have altered properties. Some studies suggest that MSCs from people with MS produce less of certain anti-inflammatory cytokines like IL-10 and may even promote proinflammatory T-cell activity, especially in secondary progressive MS (SPMS). This has led researchers to explore ways to enhance MSC function, such as pretreating them with anti-inflammatory agents before transplantation. The variability in MSC sources, preparation methods, and patient responses means that standardized protocols are still being developed.
Researchers are also investigating how stem cells can help understand MS better. By studying stem cells, scientists aim to learn why remyelination sometimes fails, what triggers immune attacks, and how to stimulate the body’s own repair mechanisms. This knowledge is crucial for developing new treatments that not only suppress the immune attack but also repair existing damage.
Currently, no stem cell treatments for MS are officially approved outside of clinical trials. Many ongoing studies are testing different stem cell types, doses, and delivery methods to establish safety, efficacy, and best practices. These trials include randomized controlled studies comparing HSCT to standard therapies and evaluating MSC therapy’s long-term benefits and risks.
In summary, stem cell transplants for MS hold significant potential to alter the disease course by modulating the immune system and promoting neurological repair. HSCT aims to reset the immune system in severe cases, while MSC therapy focuses on immunomodulation and neuroprotection. Both approaches are under active investigation, with promising early results but also important challenges related to safety, variability, and long-term outcomes. Continued research and clinical trials are essential to unlock the full therapeutic potential of stem cells for people living with MS.
