New way found to boost good cholesterol in mice

CHICAGO (Reuters) - Two research teams have found a new way to increase levels of so-called “good” cholesterol in mice, they said on Thursday in a finding that could lead to better ways to prevent heart disease in humans.

The researchers discovered that a small scrap of genetic material called a microRNA appears to regulate the production of high-density lipoprotein, or HDL, the “good” cholesterol that transports bad cholesterol to the liver to be removed from the body.

And using a type of genetic therapy to block this process can raise HDL levels in mice.

“Our study identifies a new pathway to regulate HDL levels,” Kathryn Moore of New York University Langone Medical Center, who worked on one of two studies published in the journal Science, said in a statement.

Current drugs that raise natural levels of HDL, such as niacin, cause unpleasant side effects such as flushing. And while many companies are working to develop better HDL-raising drugs, few have succeeded.

Low HDL levels can increase the risk that “bad” low-density lipoprotein, or LDL, will accumulate in artery walls, raising the risk of a heart attack.

Moore’s team found that blocking a microRNA called miR-33 in mice could increase HDL levels by as much as 25 percent, about the same effect that is achieved in people who take niacin.

MiR-33 is part of a family of genes known as sterol regulatory element-binding proteins, or SREBP, which regulate cholesterol and blood fats within cells, Anders Naar of Massachusetts General Hospital’s Center for Cancer Research, who led one of the studies in mice, said in a statement

In a series of experiments in mice, his team found that miR-33 blocks a protein called ABCA1 that is important for making HDL and for transporting cholesterol out of tissues and back to the liver.

When they used a gene-silencing technique called antisense to block miR-33 in mice fed a high-fat diet, higher levels of protective HDL cholesterol were produced.

Naar said miR-33 is the first so-called microRNA found to regulate HDL production in animals.

“This new understanding of cholesterol regulation could inform ongoing efforts to boost HDL levels in heart disease patients,” Naar said in a statement.

Analysts believe the market potential for HDL-raising drugs is well over $10 billion.

Editing by Paul Simao