Hidden threats

A NEWLY identified ‘hidden cholesterol’ that cannot be picked up in regular health checks could represent a future therapeutic target to combat heart disease. Professor Juan Carlos Kaski’s team at St George’s, University of London have shown that cholesterol that lies within the membrane of circulating red blood cells — not the cholesterol type picked up in routine blood checks — may be a marker of aggressive coronary artery disease. Research has shown that this ‘hidden’ cholesterol transported by circulating red blood cells can be trapped in deposits lining the arteries (atherosclerotic plaques), causing them to expand rapidly and block the coronary arteries.

The narrowing of the arteries by this plaque lining — which consists of cholesterol, calcium and clotting proteins, plus a fatty core — causes angina pectoris, as a result of reduced blood flow. Severe and abrupt reductions of coronary blood flow can trigger a heart attack. Professor Kaski, who has been leading the research along with Professor David Holt’s team (the Analytical Unit in the Cardiac and Vascular Sciences Division), said: “This is an important step in our investigation into why coronary artery disease progresses so rapidly in certain patients.

“If these findings are confirmed in further studies, this can result first, in the identification of a clinical marker of atherosclerosis progression that we could use to detect people who may be at high risk of developing heart attacks, and, second, in a potential therapeutic target."

“If we can reduce the cholesterol content in these red blood cells, in addition to reducing ‘conventional’ cholesterol levels, then perhaps we can cut further the chance of coronary plaques growing in higher-risk individuals.”

The new findings from St George’s were published in the May 2007 issue of the Journal of the American College of Cardiology.