Researches have been boosting stem cell populations via the method demonstrated here for more than five years, but here they're demonstrating a better and more refined outcome: "myelin [is] a material that forms a protective, insulating cape around the axons of our nerve cells so that they can send signals quickly and efficiently. But myelin, and the specialized cells called oligodendrocytes that make it, become damaged in demyelinating diseases like multiple sclerosis (MS), leaving neurons without their myelin sheaths. As a consequence, the affected neurons can no longer communicate correctly and are prone to damage. ... We've developed a gene therapy to stimulate production of new oligodendrocytes from stem and progenitor cells - both of which can become more specialized cell types - that are resident in the adult central nervous system. In other words, we're using the brain's own progenitor cells as a way to boost repair. ... The therapy uses leukemia inhibitory factor (LIF), a naturally occurring protein that was known to promote the self-renewal of neural stem cells and to reduce immune-cell attacks to myelin in other MS mouse models. ... What hadn't been done before our study was to use gene therapy in the brain to stimulate these cells to remyelinate. ... It was thought that you could use factors to stimulate the division and expansion of the progenitor population, and then add additional factors to direct those progenitors to turn into the mature myelin-forming cells. But in our mouse model, when we give our LIF therapy, it both stimulates the proliferation of the progenitor cells and allows them to differentiate into mature oligodendrocytes."

Link: http://media.caltech.edu/press_releases/13495