A new study suggests an inside-out theory of multiple sclerosis in which the disease may be triggered by the death of brain cells that make the insulation around nerve fibers, according to a new study from Northwestern Medicine and the University of Chicago researchers. Creating a mouse-model of progressive MS, scientists also used a specially developed nanoparticle that prevented MS even after the death of those brain cells.
The new study shows the possibility that MS can begin from the inside out, in which damage to oligodendrocytes in the central nervous system can trigger an immune response directly. Oligodendrocytes can possibly be destroyed by developmental abnormalities, viruses, bacterial toxins or environmental pollutants. Oligodendrocytes are responsible for the maintenance of myelin. If they die, the myelin sheath falls apart. The death of these cells can activate the autoimmune response against myelin, which is the main feature of MS. The inside-out hypothesis suggests that when myelin falls apart, the immune system interprets the products of its degradation as foreign bodies or antigens, erroneously viewing them as invaders and beginning a full-scale attack on myelin, initiating MS.
"Protecting oligodendrocytes in susceptible individuals might help delay or prevent MS from initiating. It's likely that therapeutic strategies that intervene early in the disease process will have greater impact," said Brian Popko, the Jack Miller Professor of Neurological Disorders at the University of Chicago and one of the lead investigators in the study.
The scientists also developed the first mouse model of the progressive form of the autoimmune disease, which will enable the testing of new drugs against progressive MS. In the study, nanoparticles creating tolerance to the myelin antigen were administered and prevented progressive MS from developing. The nanoparticles are being developed for clinical trials that could lead to new treatments – without the side effects of current therapies – in adults.
The study was published in Nature Neuroscience.