SEATTLE, Nov 2, 2009 (UPI via COMTEX) -- A U.S. medical researcher says he has
determined two commonly used statins have different drug and cell dependent
effects in the brain.
Professor John Albers and colleagues at the University of Washington's Northwest
Lipid Metabolism and Diabetes Research Laboratories at the University of
Washington compared the effects of two statins -- simvastatin (Zocor) and
pravastatin (Pravachol) on two different types of brain cells -- neurons and
astrocytes, which are support cells that help repair damage.
The scientists said although statins are of great value in treating high
cholesterol and lowering the risk of heart disease, studies suggest similar
statin drugs can have profoundly different effects on brain cells -- both
beneficial and detrimental.
By directly applying the drugs to cells as opposed to administering them to
animals, the scientists said they could eliminate differences in the drugs'
ability to cross the blood-brain barrier as a reason for any differing effects.
Albers and his team said they looked at the expression of genes related to
neurodegeneration, and found, despite using biologically equivalent drug
concentrations, differences between both cells and drugs.
For example, the scientists said simvastatin reduced the expression of the
cholesterol transporter ABCA1 by approximately 80 percent in astrocytes while
pravastatin lowered expression by only around 50 percent. Another difference was
that while both statins decreased expression of the Tau protein -- associated
with Alzheimer's disease -- in astrocytes, they increased Tau expression in
neurons. Pravastatin also increased the expression of another Alzheimer's
hallmark, amyloid precursor protein.
While increased levels of these two proteins may account for potential risks of
disease, Albers said large decreases in cholesterol proteins like ABCA1 should
be considered. Brain cholesterol levels tend to be reduced in elderly people,
and in such individuals the long-term effects of statin therapy could lead to
transient or permanent cognitive impairment.
The researchers said their findings reinforce the idea that great care should be
taken in deciding the dosage and type of statin given to individuals,
particularly elderly people.
The study is reported in The Journal of Lipid Research.
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Copyright 2009 by United Press International