Drugs boosting SIRT1's activity could be valuable, scientists say
THURSDAY, Oct. 11 (HealthDay News) -- A gene already associated with longer life span may also be linked to a pathway that clears cholesterol from the body, say Massachusetts Institute of Technology (MIT) researchers.
They said their finding could help lead to the creation of drugs that lower the risk of cholesterol-related diseases such as atherosclerosis (clogged arteries) and Alzheimer's disease.
The gene, called SIRT1, prevents cholesterol buildup by activating a cellular pathway that flushes cholesterol from the body using high density lipoprotein (HDL or "good" cholesterol), the team explained.
In their research with mice, the MIT team found that low SIRT1 levels resulted in cholesterol buildup in cells such as macrophages (a type of immune cell), due to reduced activity of a protein called liver X receptor (LXR). This protein is responsible for moving cholesterol out of macrophage cells. When they're full of cholesterol, macrophage cells can generate the plaques that clog arteries. SIRT1 increases LXR activity and the movement of cholesterol out of macrophages and the body by HDL.
The study is published in the Oct. 12 issue of the journal Molecular Cell.
"SIRT1 is an important mediator of cholesterol efflux, and, as such, it's predicted to play a role in the development of age-associated diseases where cholesterol is a contributing factor," senior author Leonard Guarente, professor of biology, said in a prepared statement.
"If you had a drug that could increase expression of SIRT1, that could replicate the effects of calorie restriction. This is not going to replace the need for a healthy lifestyle, but it's a supplement that could potentially make you healthier," Guarente said.
The American Heart Association has more about cholesterol.
-- Robert Preidt
SOURCE: Massachusetts Institute of Technology, news release, Oct. 11, 2007
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