Progressive forms of multiple sclerosis occur when immune cells called microglia attack the central nervous system, damaging the protective myelin sheath around nerve cells and causing symptoms such as balance problems and pain. Now scientists at the University of Cambridge believe they’ve found a new way to repair myelin—and it involves using patients’ own skin cells.
The team has published research in mice showing that stem cells taken from skin can be reprogrammed to become brain cells and then transplanted directly into the central nervous system, according to a press release. When they did that in mouse models of MS, the microglia became less destructive, reducing inflammation and limiting damage to the brain and spinal cord.
By studying the mice, the Cambridge scientists discovered that MS raises levels of a metabolite called succinate in the body. Succinate sends signals to microglia that prompt the immune cells to cause inflammation in the cerebrospinal fluid.
In the study, the researchers transplanted both the reprogrammed skin cells and neural stem cells—embryonic stem cells that are already on the way to becoming brain cells—directly into the cerebrospinal fluid. This caused succinate levels to fall, which in turn reprogrammed the destructive microglia. The study was published in the journal Cell Stem Cell.
Conquering MS has proven challenging, largely because it’s unclear what causes the immune system to attack normal cells. Several experimental approaches to treating the disease are aimed at addressing newly discovered trigger points for the disease. For example, in October, scientists at the University of Cambridge published research suggesting that repairing an error in the development of regulatory T cells (Tregs)—immune cells that prevent autoimmune responses—could prove promising in MS. And researchers at the University of Florida are developing a gene therapy technique designed to stimulate Tregs.
The University of Cambridge researchers are optimistic about their early findings with skin stem cells, particularly because the treatment would be personalized to each patient, which could reduce the risk of side effects. "This is particularly promising as these cells should be more readily obtainable than conventional neural stem cells and would not carry the risk of an adverse immune response," said lead author Stefano Pluchino of the Department of Clinical Neurosciences at the university, in the statement.