SEATTLE, Nov. 2 (UPI) -- 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.
