Blood Brain Barrier (BBB) Permeability
When the BBB is breached, the barrier that separates the blood vessels and capillaries from the brain and nervous system is damaged and antigens that may be in the blood stream are able to access the brain and nervous system and trigger possible neuroautoimmunity.
A well-documented environmental trigger is systemic lipopolysaccharides (LPS). When a person has "leaky gut," LPS can easily infiltrate the body and once in the bloodstream, it is able to inflame the BBB and open the barrier at the tight junctions. Thus, a person with "leaky gut" is prone to developing "leaky brain!"
Physical activity can also open the BBB. Athletes playing sports in which the head is often knocked (football, basketball, soccer, hockey, etc.), over time, may damage the BBB. As BBB damage happens, tissue proteins are broken off and spill into the bloodstream where the immune system will begin to make autoantibodies against the BBB, which will further damage the BBB.