Here's a more cerebral reason to lower your cholesterol

An unhealthy western diet could harm more than just your waistline - it may also increase your risk of Alzheimer's disease.

Earlier work on mice fed high-cholesterol diets found that their brain cells produced more amyloid beta, a protein linked to Alzheimer's. There is also evidence that taking cholesterol-lowering statins makes people less likely to develop late-onset Alzheimer's.

To better understand this link, Brett Garner of the Prince of Wales Medical Research Institute in Sydney, Australia, and his colleagues used human and animal cells to probe how neurons regulate their levels of cholesterol.

They found that "ABC proteins", which help control cholesterol levels in arterial walls by expelling cholesterol from the immune cells called macrophages where it builds up, were also present in neurons. When the team over-expressed the genes for these proteins in hamster and human cell lines, production of amyloid beta protein fell (Journal of Biological Chemistry, vol 282, p 2851).

The work also showed that an extracellular protein called apoE is extremely good at regulating cholesterol removal from neurons. One form of the gene for apoE is already recognised as the major genetic risk factor for late-onset Alzheimer's disease.

Garner suggests that drugs that increase expression of ABC transporters might slow the progression of Alzheimer's. Such drugs are already being used in cardiovascular research. "A lot of people think there could be converging factors involved in these diseases," Garner says.

From issue 2590 of New Scientist magazine, 08 February 2007, page 15

reposted from: New Scientist
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