The treatment of brain cancers, neurodegenerative diseases and other disorders could be revolutionized by a technique that temporarily allows drugs and other substances to pass the blood brain barrier. This is a structure that divides brain blood vessels and its tissues.
Four women with breast cancer that had spread to their brains were enrolled in a trial to see if magnetic resonance-guided focused ultrasound (MRgFUS), could safely deliver the Herceptin antibody therapy into their brain tissue. The tumours began to shrink.
The blood brain barrier is a cell wall that prevents substances from entering the brain, such as microbes or toxins, where they can cause irreparable harm to its tissues.
While there may be tiny gaps between cells in the blood vessels in the rest of your body that allow small substances through, these spaces are fused in the brain. This means that water, some gases, such as oxygen, and small fat-soluble medications such as antidepressants can pass through.
Many people have tried many different methods to get stuff through the blood brain barrier. However, it proved difficult to do so in a temporary manner, according to Eleanor Stride who is a professor of biomaterials at Oxford University. She was not involved with the research.
It would be a good idea to have a wide range of drugs available for both [metastatic breast carcinoma] and neurodegenerative diseases like Alzheimers.
MRgFUS uses concentrated ultrasound (sound waves), to open blood brain barrier in certain regions. This is done by causing microscopic bubbles containing contrast agent to oscillate. These oscillations cause blood cells to break down, which allows substances that are normally difficult to penetrate to the brain to flow through.
The study was led by Dr Nir Lipsman of Sunnybrook Health Sciences Centre, Toronto, Canada. It is believed that whatever is in the bloodstream can access the brain pathology (disease) where it is needed.
Lipsman and his coworkers had previously demonstrated that MRgFUS could temporarily open the blood brain barrier for people with a different kind of brain cancer or the neurodegenerative disorder amytrophic lateral sclerosis, but they didn't use it to transport drugs into the brains of patients.
They have now used it to deliver monoclonal antibody trastuzumab, (Herceptin), to brain diseased areas in four patients with metastatic cancer.
Science Translational Medicine published the research. It showed that the drug was taken up and the tumours responded. However, the trial was originally intended to evaluate safety.
Importantly, none suffered any adverse events. Further imaging indicated that blood brain barriers were resealed 24 hours later.
Although it has been known for some time that focused ultrasound can be used in drug delivery enhancement, this is the first time Lipsman stated that we have demonstrated drug can be delivered to the brain and that we can visualize it doing so.
Herceptin is also a large compound. If we can [get it into], we can fairly safely assume that other compounds can be gotten into the brain using focused ultrasound.
Kevin ONeill is a consultant neurosurgeon at Imperial College London's Brain Tumour Research Centre of Excellence. He said that many therapies for brain cancer require a delivery system that does more than just protect them, but also directs them to the right area.
Although injecting them into your brain is one method, this is a better option because it is non-invasive. This is a way to open a door in the blood brain barrier that leads to the desired location. This is a first step towards other therapies.
