Blood-Brain Barrier: Here's How This Tight Layer Protects Your Brain

The blood-brain barrier (BBB) is a layer of tightly locked cells that protect the brain against germs, harmful substances, and things that could lead to damage.

The Blood-Brain Barrier

The blood-brain barrier protective layer lines the blood vessels' inner surfaces in the brain. This layer is crucial for the function of the brain and nervous system.

Though this layer includes the word "barrier" in its name, it actually serves more like a filter and gatekeeper. The BBB helps keep harmful things out of the brain and helpful things inside. It also manages how different chemical molecules go in and out of the brain.

ALSO READ: Gut-Brain Connection: Here's How the Digestive System, Central Nervous System Affect Each Other

How the Blood-Brain Barrier Works

Blood vessels have a specialized cell layer known as endothelium. However, within the brain, the endothelium is actually different. The endothelial cells that line the inside of the blood vessels in the brain are packed together tightly, forming the BBB. Their incredible tightness leaves hardly any space for anything to slip without assistance. Such cells also have an outer membrane that is lipid-based.

Some things that are tiny enough could enter the BBB, while others could also pass if they are lipid-soluble. However, water-soluble and larger molecules cannot move through the BBB independently. If such water-soluble or large molecules need to pass through the barrier, they would require transportation assistance to do so.

Examples of substances and drugs that can move through the BBB independently or with assistance are anesthetics, alcohol, antipsychotic medications, anxiolytics, antidepressant medications, epilepsy or seizure medications, caffeine, NSAIDs, and sedative hypnotics. So far, complex algorithms and computer programs have listed almost 5,000 chemical molecules that can move through the BBB.

On the other hand, pathogens, including viruses and bacteria, and several toxic substances generally cannot move through the BBB.

Though the BBB is extremely secure, it still isn't perfect. The BBB can be weakened by inflammation or other conditions. Because of this, pathogens or harmful substances can enter the brain. Conditions that can weaken the integrity of the BBB can either be chronic or acute.

Disruptions and Treatment

At present, there is no way to clearly distinguish BBB problems. There are lab tests that could indirectly show issues with the BBB, especially when it comes to cerebrospinal fluid. The majority of conditions involved with BBB disruptions end up apparent through symptoms that are not related to the layer.

There are also no treatments that directly aim for the BBB. Rather, treatments typically target the conditions that could lead to BBB disruptions. These could include high blood pressure medications, brain cancer treatments, and seizure-prevention medications.

There is still no clear way to prevent BBB disruptions. The best thing to do would be to avoid circumstances or conditions that could prompt such disruptions. Some steps to take may include keeping a healthy weight, adapting a balanced diet, paying attention to infections, using safety equipment, and managing health conditions.