Using Ultrasound To Pierce The Blood-Brain Barrier

Treating the brain often requires invasive surgery, but a new technique involving ultrasound and air bubbles has now shown promise at delivering drugs through the blood-brain barrier.

One of the biggest challenges of medicating brain tumours is actually getting drugs into the organ. Your brain is well protected from invasion by untoward substances or life forms, and this protection limits what will enter from the bloodstream. There have been previous efforts to open up the barrier, but they often involve a surgical approach that is far from ideal.

What is the blood-brain barrier?

The barrier is essentially a thin lining of cells that are tightly bound together, preventing most molecules from leaking through. This barrier means that about 95% of drugs have no effort on brain tissue and only certain small molecules like alcohol, caffeine and nicotine can get through.

What's new?

A Canadian team used an innovative approach to the problem of getting cancer drugs into a patient's brain - ultrasound.

After injecting chemotherapy drugs into the bloodstream, they added tiny air bubbles at the same time. When they focused ultrasound on a specific region of the blood-brain barrier, they could expand and contract these bubbles; which loosened the junctions enough to squeeze the drugs through.

“By using a focused ultrasound technique, you can apply chemotherapy directly to a lesion. With traditional chemotherapy, you have to apply a large dose that wreaks havoc on the body. This opens the doors to more treatments for other diseases with a similar technique.”

How effective is it?

This is a newly tried procedure, and for now we don't know how much of the drug was able to enter. It does appear that the process is reversible however, and non-invasive. This means it could be fairly easily replicated to help deliver a range of different material against different diseases in the future. It may even help gene therapy tactics to reach the brain, without requiring traumatic injections.

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