blood brain barrier

Blood Brain Barrier [Show Notes]

 in Brain / Podcasts  tagged blood brain barrier / drugs / episode / HIV / rabies / virus by

Basics

The blood brain barrier is the last layer of cells between what’s in your blood and the extracellular fluid around your brain cells.

You’re born with it!  It’s main job is filtration.

2 ways things get through the blood brain barrier:

  • Passive diffusion: small, neutral molecules (water, gases, lipid-soluble)
  • Active transport: glucose, amino acids, drugs (like a revolving door)

Permeability: how easily something can pass through a layer without work

Things that change permeability:

  • Inflammation – stretches layer and makes holes bigger (meningitis, injury)
  • Multiple sclerosis – an auto-immune disease that can degrade the BBB
  • Alzheimer’s – BBB becomes overwhelmed with antibodies and burns out

*Scary Section*

Rabies is a virus that is small and can get through the blood brain barrier but the immune system cells, antibodies from the vaccine, and medicines can’t.
HIV encephalopathy is caused when a mutation of the HIV gets into the brain and use brain cells to replicate (rather than the well-known T-cells of the immune system).  There is also a rare symptom of HIV called HIV-associated dementia.

Callback

microchimerisms – Pregnancy causes the permeability of many areas of the body to change, and this includes the BBB.

Test Yourself

Drugs that have central nervous system effects (good) or side effects (bad) cross the BBB.  See what you know of different medications and what job they’re supposed to do and what negative side effects they cause and see if you can guess if they cross the BBB.

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Music Credits:  “Radio Martini” Kevin MacLeod (incompetech.com)  Licensed under Creative Commons: By Attribution 3.0  http://creativecommons.org/licenses/by/3.0/

Male DNA in the Female Brain

 in Brain / Podcasts  tagged Alzheimer's / blood brain barrier / brain / DNA / microchimerism / pregnancy by

*Sorry again for crying baby*

Male DNA In The News

The news reported that scientists had discovered a link between male DNA found in the brain of the women who gave birth to sons.

Microchimerism = DNA fragment of another organism that incorporates into you

This particular microchimerism involves the Y chromosome (because otherwise, you wouldn’t know it was specifically male).

Other documented microchimerism studies have reason to believe they may be beneficial – especially in a process called immuno-surveillance (when the immune system is patrolling around looking for things that don’t belong there).

The blood brain barrier is the last layer of cells between what’s in your blood and your brain cells.  DNA fragments are small and can easily pass through the BBB, especially during pregnancy when membrane permeability (the penetrable-ness) has increased all throughout the body already.

The primary resource written by the scientists that did the study of the female brains states that their findings were pretty much inconclusive – partly due to the small sample size of brains they had available.  And they couldn’t study living people.  They were mostly trying to decide if this male microchimerism had a positive or negative effect on Alzheimer’s risk.  The final conclusion – we dunno.  Another obstacle was that the complete health history of the samples they used was not known.

Other sources have stated hypotheses regarding the number of children a woman has and the risk of early onset Alzheimer’s.

This issue with reporting on studies like these is that Alzheimer’s has so many factors that may increase or decrease risk and science is pretty sure there’s NOT just one thing that will cause or prevent someone from developing this disease.

The only thing they could conclude is that microchimerisms are evolutionarily significant.

Here’s the primary journal article.

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Music Credits:  “Radio Martini” Kevin MacLeod (incompetech.com)  Licensed under Creative Commons: By Attribution 3.0  http://creativecommons.org/licenses/by/3.0/