Your Brain’s Defense – The Blood Brain Barrier
Your brain has a defense mechanism in place to help keep unwanted toxins out and prevent you from brain injury. This defensive device is called the blood brain barrier and it is made up of tiny capillary junctions that separate the brain and the cerebrospinal fluid. These junctions are 100 times tighter than that of other capillaries in your body making it harder to permeate. The blood brain barrier structure is similar to that of a cell wall; only certain types of molecules are able to pass through. It is this barrier which makes it difficult deliver medication to help the brain.
Getting Past the Blood Brain Barrier
For decades, scientists have been trying to figure out ways to safely bypass the blood brain barrier so that they could transport drugs, like chemotherapy drugs, to the brain. They have tried manipulating the drug itself to make it more permeable to blood brain barrier. This is a complex process because once in your system, your body will begin to distort the drug’s molecular structure. Scientists have also tried delivering the drug directly to the brain but this requires invasive and dangerous surgery. Finally, scientists have attempted to bypass the blood brain barrier completely such as through the nose. Intranasal delivery is a practical, non-invasive way to distribute drugs to the brain without altering the drugs. Patients who were administered drugs through the nose reported having fewer side effects. However, the concentration in different regions of the brain varies with each drug and can cause its own set of problems.
Another Way Around the Barrier
Scientists have found another way around the blood brain barrier by using ultrasound and bubbles. It sounds like something of a science fiction book, but studies have shown that this combination works. Neurosurgeon Alexandre Carpentier invented the SonoCloud ultrasound device to help patients with brain cancer, specifically glioblastoma. Glioblastoma is the most common and deadliest form of primary malignant brain tumors. Its median survival rate is 15 months and its cause is unknown, though scientists are leading toward genetic mutation.
The way the SonoCloud works is the device is surgically implanted near the patient’s brain tumor after the patient is administered a local anesthetic. Then when it’s time give the patient their chemotherapy treatment, micro bubbles are injected into the bloodstream. After the bubbles are injected the SonoCloud device sends ultrasound waves into the brain. The ultrasound waves excite the micro bubbles and put pressure on the blood brain barrier causing it to temporarily open. Once the blood brain barrier is open, the chemotherapy drug can pass through to the targeted tumor. Carpentier’s trial patients said they didn’t feel the procedure when it was happening and also said they didn’t want the device removed even though that was the plan after six months of treatment.
Ultrasound Could Help with Other Brain Diseases
Scientists in Australia are studying the effectiveness of ultrasound on Alzheimer’s disease in mice. The combination of micro bubbles and ultrasound waves reduced the number of amyloid-β plaques present on the blood brain barrier. Also the treated mice showed improved memory after treatment compared to the untreated mice. The presence of amyloid-β plaques is thought to be a prime suspect in the death of brain cells. Alzheimer’s disease is caused by brain cell death and dramatic shrinkage of the brain resulting in the loss of nearly all functions. This study is exploratory and still in pre-clinical stages but it gives hope to the neurological community for new treatments for other neurological diseases and disorders.
Extraordinary Advances Through Science
Modern science has brought the world so many brilliant advancements and treatments. It’s thrilling to think that we’re one step closer to one day having the cure for brain cancer.