Blood-Brain Barrier Opened for the First Time in Humans

Neuroscientists have successfully managed to open and close the blood-brain barrier, on much demand, for the first time ever in humans. The breakthrough in medical research provides new hope for a more effective treatment of cancerous brain tumours and neurodegenerative disorders, as doctors may now be able to deliver drugs to remote parts of the brain.

The blood-brain barrier is a sheath of cells (lined in green) surrounding blood vessels (in black) in the brain protecting the brain cells (lined in red). The barrier allows the transport of vital molecules required for normal neural function such as glucose, water molecules and amino acids. However, larger molecules including drugs cannot penetrate the protective shield. Image Credit: C.J. Guerin, MRC Toxicology Unit / Science Source http://www.brainfacts.org/brain-basics/neuroanatomy/articles/2014/blood-brain-barrier/

The blood-brain barrier is a sheath of cells (lined in green) surrounding blood vessels (in black) in the brain protecting the brain cells (lined in red). The barrier allows the transport of vital molecules required for normal neural function such as glucose, water molecules and amino acids. However larger molecules, including drugs, cannot penetrate the protective shield.
Image Credit: C.J. Guerin, MRC Toxicology Unit / Science Source
http://www.brainfacts.org/brain-basics/neuroanatomy/articles/2014/blood-brain-barrier/

The blood-brain barrier (BBB) is an important protective lining that wraps around the blood vessels in the brain. The tenacious barrier prevents harmful toxins in the bloodstream from entering the brain tissue and prevents any common bacterial infections from occurring in the brain. However, the all-too-protective sheathing poses as a major obstacle for treating neurodegenerative disorders and cancerous brain tumours, as medicinal drugs are unable to penetrate the defensive barrier and reach the specific brain tissue.

A recent study, carried out by leading neuroscientist Michael Canney and his team of specialists at the medical start-up company CarThera in Paris, showed that the BBB can be made more permeable using an ultrasound brain implant and injection of microbubbles. The study was carried out on four patients suffering from one of the most aggressive form of brain cancer known as glioblastoma.

Patients suffering from glioblastoma commonly undergo vital brain surgery to remove the tumour, followed by treatment with chemotherapy to destroy any residual cancerous cells. Tumours cause inflammation in the surrounding blood vessels making the BBB more permeable allowing a small amount of chemotherapy drugs to pass through. However, Canney told New Scientist that if a larger volume of drugs were able to penetrate through the barrier then the impact of the treatment would naturally be much greater.

An ultrasound transducer was implanted into the hole in the brain of the four patients who had undergone surgery to have the tumour removed, followed by an injection of microbubbles. The transducer released low-intensity vibrations, causing the cells of the BBB to push apart, making the barrier more permeable for approximately six hours. During this time frame, the patients received normal treatment of chemotherapy and an MRI scan revealed that a marker chemical, injected alongside the microbubbles, had successfully crossed the BBB. Canney and his team hope that the chemotherapy drugs had also passed through and more of the drug was being delivered effectively to the brain tissue. Canney has also suggested that it may be possible for certain antibodies to pass through the barrier, once opened, allowing the body’s immune system to launch an attack against cancerous cells.

Although it will be a few months yet before Canney can determine the complete effect of the procedure on tumours, the ability to open the BBB in humans is considered a revolution in medical research and can open new doors to effectively treat numerous brain disorders.

 

Related stories: “Blood-brain barrier opened on demand”- Helen Thomson, New Scientist, 25th October 2014

“Blood-Brain Barrier Opened For The First Time In Human Patients In Cancer Breakthrough”- Chris Weller, Medical Daily, 22nd October 2014

Feature Image: http://blog.smw.ch/breaking-and-building-the-wall-the-biology-of-the-blood-brain-barrier-in-health-and-disease/

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