It is a deadly disease that has so far evaded a complete cure. Successful treatment of rabies depends on how quickly medical help is given after exposure to the virus, and if it manages to reach the nervous system then it is almost invariably fatal. But the deadly virus may hold the key to solving one of the trickiest problems in medicine.
The human body has evolved such an efficient protection system, that for a long time doctors have been trying to figure out a way to breach the blood-brain barrier in order to deliver drugs to the brain. It seems that turning to nature itself may well help solve the problem. By studying how the rabies virus manages to infect brain tissue, researchers may have found a way to deliver tumor-killing drugs.
During its long history of evolution, the rabies virus has found a way to effectively bypass the blood-brain barrier, rather than breach it. When someone is infected with rabies, it is most often delivered to the muscle tissue through the bite of an infected animal, like a dog or a bat. The virus then travels through the tissue until it hits upon the central nervous system, using this to travel up and into the brain. Researchers are now mimicking this process in order to find a novel way to get drugs to brain cancers.
In a new study, published in Advanced Materials, researchers engineered gold nanoparticles into the shape of the rabies virus and coated them in some of the surface proteins found on the virus, before injecting them into mice that were bred to have brain tumors. They found that within hours the particles had migrated through the nervous system of the mice and into the brain. By then heating these particles with lasers that pass harmlessly through the skin, the researchers claimed that they were able to significantly shrink the brain tumors due to the heat emitted from the gold.
Whether or not this research could lead to an effective treatment for brain tumors is, however, still to be seen. Some researchers question whether or not the gold nanoparticles only home in on the tumor cells, or if they are also found in other tissues of the body, meaning that any treatment with lasers could in fact have inadvertent side effects and kill other healthy body cells. If these questions cannot be addressed, it will make it significantly more difficult to get approval for use in humans.