In Mice, Cancer Drug Shows Effect on Alzheimer's Symptoms
The results suggest that bexarotene could possibly help the approximately 5.4 million Americans with Alzheimer's disease, according to the neuroscientists at Case Western Reserve University School of Medicine.
However, while studies involving animals can be useful, they often fail to produce similar results in humans.
Bexarotene is approved in the United States to treat skin problems caused by cutaneous T-cell lymphoma.
The body's inability to clear amyloid beta from the brain is a major factor in the development of Alzheimer's disease, according to a university news release. Previous research showed that the main cholesterol carrier in the brain, apolipoprotein E (ApeE), plays an important role in clearing amyloid beta proteins.
In this study, the researchers found that bexarotene increased ApoE expression, and the elevated levels of ApoE boosted clearance of amyloid beta from the brain. Bexarotene stimulates retinoid X receptors (RXR), which are proteins that control the production of ApoE.
Within six hours of receiving bexarotene, soluble amyloid levels in the mice fell by 25 percent and the effect lasted for three days. This decrease was associated with rapid improvement in a wide number of behaviors in mice with Alzheimer's, according to the release.
In addition, bexarotene treatment also rapidly stimulated the removal of amyloid plaques from the brain, the researchers said. The plaques are accumulations of amyloid that form in the brain and are a hallmark of Alzheimer's disease.
"This is a particularly exciting and rewarding study because of the new science we have discovered and the potential promise of a therapy for Alzheimer's disease," study senior author Gary Landreth, a professor of neurosciences, said in a university news release.
"We need to be clear; the drug works quite well in mouse models of the disease. Our next objective is to ascertain if it acts similarly in humans. We are at an early stage in translating this basic science discovery into a treatment," he added.
The study appeared Feb. 9 in the journal Science.
The U.S. National Institute on Aging has more about Alzheimer's disease.
Posted: February 2012
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