Protecting our brain protector

Healthy Aging

Our brains are losing their VIP room.

In this Whole Body Health Series, we are sharing the latest science on our whole body, from our cells on up.

This week, we’re moving from cellular to organ health, starting with our big, beautiful brains and the importance of a working blood-brain barrier to help our brains maintain their VIP (or VIO for Very Important Organ) status.

I’ve definitely heard of the blood-brain barrier, but what exactly is it?

It used to be that our brains were protected from many of the insults received by the rest of our bodies, thanks to the blood-brain barrier, also called the BBB. Simply put, our BBB involves a handful of tricks used by vessels in our brain to keep bad stuff (like bacteria, toxins, and inflammatory cells) from crossing over to our neurons.

As described by Daneman and Prat, BBB’s tricks include:

• Tighter adhesions between vessel cells and slower transport of molecules within cells, which prevent invaders from sneaking into our brain.
• Impressive selectivity on which molecules make it across the BBB, including tailored mechanisms that transport core nutrients that our brains need to thrive.
• Less “stickiness” for bacteria, which keeps pathogens moving along and out instead of infiltrating our brain.

The result is a well-balanced and healthy brain.

Alas, as we age, our BBB starts to break down. Worse yet, as described by Wu et al., we’re seeing signs of compromised BBBs in younger people, too. In fact, leaky BBBs in younger people have been linked to depression.

How leaky BBBs cause cognitive decline, depression and dementia.

As described in Knox et al.’s review, here are a few things that happen when our BBB is compromised:

• Infiltrating inflammatory cells. Inflammation crosses from our vessels into our brain, exacerbating proinflammatory cytokines IL-6 and TNFɑ.
• Impaired myelin sheaths. When our neurons’ protective fatty coats are damaged, signals from one neuron to another are slowed.
• Damaged neurons. Direct damage to our brain cells can also occur.
• Activated microglia. All of the above trigger inflammatory cells within our brains, called microglia.

Together, these damaging processes can snowball and lead to neurodegeneration.

So, what causes our BBB to break down in the first place?

Knox et al. go on to share the two primary instigators that weaken our BBB over time:

1. Inflammation
2. Oxidative stress

This is not really mind-blowing news, since inflammation and oxidative stress are the enemies for all of our cells – including those that make our BBB.

Restoring our BBB.

Due to the importance of the BBB, it makes sense that a lot of research has been underway to figure out how to restore our BBB. It’s hard to restore home damage done by a water leak if you don’t fix the leak, right? Same for our brains.

As summarized in the Knox et al. article, here are some of the must-have skill sets of molecules being tested to restore the BBB. A BBB-restoring molecule should be able to:

• Suppress or lower oxidative stress
• Stop infiltration of inflammatory cells
• Lower proinflammatory cytokines
• Provide neuroprotective effects
• Protect myelin sheaths

While this research is still in its early stages, it is certainly promising to see focused science to restore our BBB and protect our brain health.

The gut-brain axis: How our gut & related fatty acids protect our BBB.

One of the most promising avenues of research on the long-term protection of our BBB is the surprising beneficial role of gut microbes and related fatty acids. This is promising because improving our BBB via our gut is very doable.

For example, Hoyles et al. have shown that propionate (C3:0), a short odd-chain fatty acid that bacteria in our gut produce, has protective effects on the integrity of the BBB and junctions between the BBB cells. Knox et al. propose that other gut metabolites are likely to help support our BBB, too.