The Purge And The Blood-Brain Barrier

The other day I was watching this movie called “The Purge.” In this movie, all kinds of crime are legal for one night a year. That night, either you go out to find a way to release your criminal instincts, or you install a very powerful security system to protect yourself and your family (since police and medical services are not available during that time).

 The following day, I was reading about the nervous system. In my reading, there was this one part about something called the blood-brain barrier and I thought “OMG this is just like the movie.”

In the movie, there is this one family perfectly locked up for the night, no one can get in. However, nobody knew that someone with no good intentions was inside the house before they locked up. Then this man appears on the street asking for help and the little boy decides to let him in without his parents’ permission. The situation here is that they cannot disable the security system again to get the strangers out because it could cause more bad people to come inside. Besides, there is also the problem that there is no police or anything to help them get through the night. That’s as far as the resemblance goes.

The blood-brain barrier has sort of the same situation. Since neurons are not very easy to replace once they have been damaged by a virus, they need to be particularly protected. That is why we have a barrier that separates the blood from brain cells. This barrier (as well as the security system in the movie) prevents many chemicals and bacteria from coming into the nervous system; however, it also keeps away may nutrients that cells need in order to function (which would be medical services, police, and fire fighters in the movie). The blood-barrier can only be trespassed by a few small, uncharged molecules such as O2 and CO2, in addition to certain fat-soluble molecules. Besides, active transport systems pump glucose and certain amino acids across the membrane. However, most large molecules and electrically charged molecules cannot cross from the blood to the brain.

 

Although the lack of nutrients is not a positive feature, our brain cells have adapted to it. The real problems is what happens once a virus does get pass the barrier. Just like in the movie, the virus will try (and possibly succeed) to kill you. If it can’t, at least it will stay inside your nervous system (your house) the rest of your life (the night). Besides, when the cells of the blood vessels that form your barrier shrink, harmful chemicals may get in and cause certain diseases such as Alzheimer’s.

 

The question here is: how can we treat Alzheimer’s or Parkinson’s disease, or some brain cancers if the chemicals used for the treatments are not able to cross the barrier? In the following video Devin Wiley explains his approach to this issue and his theory for overcoming the barrier.

http://www.youtube.com/watch?v=WLEPr3mz4qc