Surprising Science: Alzheimer’s Disease Advance
Alzheimer’s disease damages brain tissue in a variety of ways, but one of the most important seems to be the buildup of “plaques.” The deposits contain protein called beta-amyloid. Normally, beta-amyloid is produced and then removed at a more or less constant rate, but not in individuals with Alzheimer’s disease.
Beta-amyloid is normally removed from the brain with the help of a molecule called apolipoprotein. One version of this molecule, ApoE, increases a person’s risk of Alzheimer’s and appears to be linked to beta-amyloid buildup.
Meanwhile there is bexarotene, a chemical used in cancer treatments (officially for cutaneous T-cell lymphoma but unofficially for some other cancers). Researchers at Case Western Reserve University School of Medicine used bexarotene in mice that have a condition similar to human Alzheimer’s to change the relationship between ApoE and beta-amyloid. The drug caused plaques to be removed from much of the neural tissue. The behaviors of the mice on learning and memory tasks also changed in ways indicating that the effects of the Alzheimer’s-like condition was reversed, at least partially. A mere 72 hours of treatment with bexarotene “cured” misdirected nesting behavior and caused improvement in other tasks. Olfactory sense improved in some of the mice over a nine-day period.
There are reasons to be very positive about this result, but also reasons to be very cautious. Among the reasons to be cautious are