There are so many clues in the medical literature suggesting that a break in the tight barrier around the brain, the blood-brain-barrier (BBB), can allow the pathological process of multiple sclerosis to start. Immune cells normally can’t get into the brain unless there is a breach in the BBB; we know the Epstein-Barr Virus (the glandular fever virus) disrupts the BBB, and people who have had EBV infection are at least 10 times more likely to get MS; many studies have shown that trauma to the head can precipitate MS.
Now scientists at the Gladstone Institutes, in an elegant study, have shown that, in an animal model, just a single drop of blood in the brain substance triggers a cascade of events leading to demyelination. Their findings, published in the major international journal Nature Communications, may be the beginnings of a unified theory of how MS starts, and therefore how it can be stopped.
Anything leading to blood getting into the brain, for instance vascular disease where blood vessel damage leads to leakage of blood, or build up of pressure in the blood vessels leading to leakage, or direct damage of the BBB, could conceivably act as a trigger for MS. The critical molecule in blood appears to be fibrinogen, a protein responsible for blood clotting. Knowing this enables researchers to target that molecule in developing treatments. Exciting stuff!