London: Scientists have found a new way to smuggle anti-cancer drugs past a natural barrier that protects the brain from outside attacks, a method they say could help treat brain tumours effectively and cut side-effects.
The brain has a defence system that protects it from large, potentially toxic molecules circulating in the blood.
This function, however, ends up in protecting cancer cells inside the brain from drugs.
Now, researchers at Germany`s Max-Delbruck Centre for Molecular Medicine have developed a "nanocarrier" which can hijack the barrier`s own mechanisms and help get the drugs through.
According to the team, molecules which are needed by the brain activate receptors at the barrier, and are actively pulled through.
They now found a molecule which could trigger this process, and constructed a tiny capsule containing the drugmitoxantrone, with this molecule attached to its surface.
The disguise appeared to work, at least in mice with breast tumours implanted into their brains, the BBC reported.
In comparison with untreated mice, the "nanocarrier" mitoxantrone reduced tumour area by 73 per cent, and more importantly, by 45 per cent in comparison with mice simply
given the drug on its own.
It was also found reducing the extent of side-effects in the mice. While those given only the drug had weight loss, dehydration, and stomach disorders, there were no noticeable
side effects in those given the nanocarrier treatment, the scientists noticed.
This, they said, was because the molecule on the surface of the liposome capsule marked it for delivery to brain cells, stopping it from wreaking havoc in other parts of the body.
Study author Andrea Orthmann said the "nanocarrier" could potentially hold not only other cancer drugs, but also drugs aimed at other brain conditions.
She said: "The liposomes have the potential to be used in several other diseases, including neurodegenerative ones such as Alzheimer`s Parkinson`s and Huntingdon`s disease, as well as other tumours."
However, she conceded that much more work would be needed before the technology could be used in humans.
Roy Rampling, a professor emeritus at Glasgow University, said: "The idea is to encapsulate drugs to deliver their payload once they reach the brain.
"You need to get sufficient drug into the brain without increasing side-effects, and because it is encapsulated, it doesn`t produce the same level of toxicity in other organs,
particularly the bone marrow."
Trevor Lawson, from Brain Tumour UK, which supports similar projects, said that there was an urgent need to find new ways to deliver drugs across the blood brain barrier.