To restrict the passage of large toxic substances from the bloodstream into the brain, each person has a protective blood barrier lining the blood vessels in the brain.
“The blood-brain barrier (BBB) has been a persistent obstacle to delivering valuable therapies to treat disease such as tumours,” said Dr Todd Mainprize, the principal investigator of the study and Neurosurgeon at the Centre.
Mainprize said that we are encouraged that we were able to temporarily open this barrier in a patient to deliver chemotherapy directly to the brain tumour.
The research team infused a chemotherapy drug and tiny, microscopic bubbles, into the bloodstream of the patient who had a malignant brain tumour.
The microbubbles pass harmlessly through the circulation and were smaller than red blood cells.
The researchers then used MRI-guided focused low-intensity ultrasound waves on targeting blood vessels in the blood-brain barrier (BBB) area near the tumour.
The waves repeatedly compress and expand the microbubbles, causing them to vibrate and loosen tight junctions of the cells comprising the BBB.
Once the barrier was opened, the chemotherapy flowed through and deposited into the targeted regions.
"Some of the most exciting and novel therapeutics for the treatment of malignant brain tumours are not able to reach the tumour cells because of the blood-brain barrier," said Mainprize, also an Assistant Professor at the University of Toronto.
Mainprize said that this technique will open up new opportunities to deliver potentially much more effective treatments to the targeted areas.
Less than 24 hours after breaching the blood-brain barrier, the tumour and some surrounding tissues were surgically removed and sent to pathology to measure differences in the concentration of chemotherapy that deposited in the area treated by the focused ultrasound and the area not treated.
The chairman of the Focused Ultrasound Foundation, a US-based non-profit organisation, Neal Kassell said that Breaching this barrier opens up a new frontier in treating brain disorders.
The success of this research opens up the potential for delivering drug therapies to parts of the brain protected by the blood brain barrier, including researching treatments for patients with various kinds of brain tumours, Alzheimer's disease, and some psychiatric conditions.
The case was the first of up to 10 participants in this study, which is testing for feasibility, safety and preliminary efficacy. These participants are those who had already scheduled for traditional neurosurgery to remove parts of their brain tumour.
By Ruchi Singh
reporter
Park Sae-jin
swatchsjp@ajunews.com
