Of Mice and Memory – New Treatment for Alzheimer’s?

Scientists at Case Western Reserve University School of Medicine discovered some surprising results while testing an FDA approved cancer drug, bexarotene, on mice. The drug works by stimulating retinoid X receptors. This, in turn, elevates Apolipoprotein E (ApoE) levels in the brain, which helps clear amyloid beta proteins. The results are fast and dramatic. The drug appears to reverse the effects of Alzheimer’s disease and the attendant pathological, cognitive, and memory deficits.

There are roughly 5.4 million people suffering with Alzheimer’s in the U.S. and many treatments have been researched, up to and including electrical stimulation. The use of bexarotene is one of the more practical and effective potential treatments, and since it’s already FDA approved, human trials are not far off.

Alzheimer’s disease results when the body loses its ability to clear amyloid beta from the brain. In 2008, Gary Landreth, a professor of neurosciences at Case Western Reserve, found that ApoE , a cholesterol carrier helped clear the amyloid beta proteins. The next logical step was to find some way to stimulate the production of ApoE in the brain. Bexarotene appears to answer that issue.

What makes the results of this study so encouraging is the speed and efficiency by which the changes take place. Within six hours of administering treatment, there was marked improvement in mouse memory, and it lasted for several days. One indication of this phenomenon was observed in the nesting instinct. Mice with Alzheimer’s showed no interest in nesting before the treatment. They had lost the ability to associate nesting materials with the natural desire to nest. Three days into bexarotene treatment, the mice returned to normal behavioral patterns and used the material – in this case tissue – to nest. The sense of smell and response to smells were also enhanced.

In addition to cognitive abilities, there is physical evidence of improvement. The hallmark of Alzheimer’s is amyloid plaques that form on the brain. The research team found that within 72 hours, half of the amyloid plaques were gone. In ten days, more than 75% of the plaques had disappeared. This demonstrated that the treatment reduced both soluble amyloid and compacted deposits. Because the best Alzheimer’s treatment tested previously takes months to achieve similar results, Professor Landreth and his team are understandably excited.

Bexarotene has few side effects and a good track record. Researchers hope that the treatment works as well on humans as it does on mice. Since the drug is already approved, there are fewer barriers to human trials.

Could an Alzheimer’s cure be just over the horizon? We’ll be waiting anxiously to find out!