Friday, February 10, 2012

Cancer drug swiftly reverses Alzheimer's disease

Sometimes drugs are useful for treating diseases they were not originally designed for. When scientists learn more about how a certain drug works, they sometimes find that it is much more widely applicable than previously thought. Such is the case for bexarotene, which is normally used to treat lymphoma, but is now also used for lung and breast cancer. Scientists from Case Western Reserve University discovered it is also useful for something totally different: alzheimer's disease. They found that it works well on mice, which means we need clinical studies to observe its efficacy in humans.

Experiments
Mice with alzheimer's-like damage in the brain were used in the study. By administering bexarotene to the brain, the scientists hoped to rid it off toxic accumulations called placques. What they found was quite surprising: animals that received bexarotene treatment were able to clear almost half of the placques in their brain in just 72 hours. Social and cognitive deficits induced by the brain damage were rapidly reversed. This is very hopeful for alzheimer's patients, despite the research being carried out in mice.
Bexarotene.
Mechanism
The fact that scientists came up with the idea to use an anti-cancer drug to treat alzheimer's may sound surprising, but the underlying mechanism makes it a logical step in drug testing. It is known that alzheimer's is caused by accumulation of a badly folded protein, called beta amyloid. It damages nerve cells, which consequently die. It was already known that deposition of protein can be prevented by a substance called ApoE, which is in turn activated by a receptor called RXR. Bexarotene just happens to activate this receptor.

Clinic
Because the study was performed with mice, there is much that needs to be done before this can actually be used clinically. Studies that investigate the drug's efficacy in human patients are paramount. The scientists hope to start clinical trials soon, because bexarotene is already approved for use in humans, which would make the treatment safe.

Other attempts
Alzheimer's is a neurodegenerative disease that affects the memory centre of the brain. During later stages, cognitive functions of the brain are also affected. It is currently still incurable, but various attempts are made to combat the devastating disease. Many of them are aimed at reviving the damaged parts of the brain with stem cells. It is also possible to electrically stimulate the brain to improve memory cell generation.

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