Doctors have shown that it is possible to safely deliver medicines directly to a person鈥檚 brain, in a world-first cancer treatment that involves breaching the 鈥渂lood-brain barrier鈥�.
The method involves temporarily making blood vessels in a certain brain region more porous, to let a drug flow out of the bloodstream and reach tumour cells.
Four women with breast cancer that had spread to the brain have had their tumours shrunk by a drug called Herceptin using this method.
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Blood vessels in the brain are normally more impermeable than elsewhere, as cells that make up their walls are more tightly joined to each other. This results in a blood-brain barrier that helps stabilise brain cells鈥� chemical environment and keeps out potential toxins and microbes.
快猫短视频s have been trying for decades to get drugs past this barrier. One of the leading approaches is to inject tiny bubbles into the blood, then aim beams of ultrasound at the targeted brain region. The ultrasound makes the bubbles vibrate, which widens the gap between the cells in the blood vessel wall.
This method has been demonstrated before, but never been shown to be effective until now. at Sunnybrook Research Institute in Toronto, Canada, and his colleagues used this method to deliver the cancer treatment Herceptin to tumours that had spread to the brain in four women with breast cancer.
After having treatments every three weeks, up to six times, their cancers shrank by an average of 19 per cent. The drug had been labelled with a mildly radioactive compound, allowing brain scans to show that it had reached their brain tumours.
The results don鈥檛 mean there is now a cure for brain tumours, as most advanced cancers eventually develop resistance to drugs such as Herceptin. But shrinking the tumours of the four women is a proof of principle that the blood-brain barrier can be breached, says at Imperial College London, who wasn鈥檛 involved in the study. 鈥淔or me this is the dream.鈥�
One woman has since died, due to progression of tumours that had spread elsewhere in her body, but the other participants are currently stable.
The method could in future help if effective treatments are developed for neurological conditions such as Alzheimer鈥檚 disease and motor neurone disease, says Lipsman. 鈥淔rom a technological perspective, it鈥檚 a major breakthrough.鈥�
Science Translational Medicine
