Blood-Brain Barrier 101: Everything You Need to Know

John Bachman
3 Mins
Blood-Brain Barrier 101: Everything You Need to Know

If you’re a regular reader here at the BIPRI Brain Power Blog, you’ve likely encountered the term “blood-brain barrier.” Or, maybe you’re new here, but still curious as to what it is. The critical blood-brain barrier doesn’t have to be as mystifying or complex as you think it is! Read on for a better understanding of the blood-brain barrier… 

What is the Blood-Brain Barrier?

Nobel Prize winner Paul Ehrlich discovered the blood-brain barrier in the late 19th century when he injected blue dye into the bloodstream of an animal and was surprised to see most of the tissue turn blue... with the exception of the brain and spinal cord. This indicated a barrier between the bloodstream and the brain.

The blood-brain barrier, or BBB, surrounds most of the blood vessels in the brain. It is formed by tight junctions of endothelial cells, as well as other proteins and cells. (Endothelial cells line the walls of blood vessels.) The BBB serves as protection to prevent toxins, pathogens, neurotoxins and other potentially harmful substances from entering the brain from the bloodstream.

The brain is highly susceptible to substances that could be disruptive or toxic to its delicate balance. Even neurotoxins produced and released into the bloodstream for the benefit of other organs may become dangerous if levels become too high in the brain itself.

The tightly packed endothelial cells make the BBB highly selective and restrictive of what gets through. Substances allowed to pass easily through the BBB include water, certain gases, and lipid (fat) soluble compounds. Other necessary nutrients such as glucose can be transported across the BBB with effort or attachment to other compounds.

Is the Blood-Brain Barrier Solid?

Not entirely. Certain regions of the brain lack the BBB, allowing substances to pass freely into and out of that section of the brain. These circumventricular sections allow the brain to monitor the makeup of the blood. These functions include

  • Secreting melatonin and neuroactive peptides (controlling the circadian (awake/asleep) rhythm)
  • Releasing neurohormones, such as oxytocin, into the blood
  • Detecting toxins in the bloodstream and triggering a vomit response to expel harmful substances from the stomach before further damage occurs

While some gaps in the BBB are natural, breakdowns in the BBB can occur, causing detriments to the brain. Trauma, radiation and even high blood pressure may weaken the blood-brain barrier. Additionally, bacterial infections such as meningitis could make the BBB more porous, allowing toxins into the brain tissue.

Is the Blood-Brain Barrier Good or Bad?

Yes. Wait, what? While keeping toxins out is obviously a good thing, the difficulty of substances passing through the blood-brain barrier makes most treatment drugs notoriously hard to penetrate. Whether there is an infection in the brain, a tumor or a neurological or mental disorder, medications that can enter the brain are necessary. There are a few ways around the BBB to provide treatment.

One option is to “trick” the blood-brain barrier into letting medications in by using a Trojan Horse. This is accomplished by fusing the drug to transporter protein that can pass through. Another method uses ultrasound technology. Used in the treatment of Alzheimer’s disease, ultrasound can temporarily open the BBB and improve cognition by decreasing the level of toxic plaque in the brain. Using ultrasound may also permit antibodies and other medications to penetrate the brain for treating other conditions. Most importantly, the use of ultrasound technology does not damage the brain.

Up to Speed on the Blood-Brain Barrier

The blood-brain barrier is a highly technical part of the body, and tricky to understand. But hopefully now you do have a better understanding of this amazing feature! If you have questions or want to dive deeper into the BBB, our team at BIPRI is here to help. Feel free to call 888-549-5519 or use the online chat feature for more information about the BBB and how it’s affected by some of our products and supplements.

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