From Featuring Dr Chris Steele MBE

Ultra-bad cholesterol found

More sticky than normal LDL-cholesterol

Scientists have discovered why a new type of cholesterol is "ultra-bad" for the heart.

LDL-cholesterol, often called bad cholesterol, is transported from the liver to other parts of the body. High levels of LDL-cholesterol in the blood are linked to blood clots, heart disease and stroke.

However, a new type of cholesterol - called MGmin-LDL - appears to be stickier than normal LDL, making it easier to attach to the insides of artery walls. MGmin-low-density lipoprotein (LDL) is more common in people with type 2 diabetes and the elderly.

The researchers at Warwick University discovered that MGmin-LDL consists of normal LDL, but with extra sugar molecules, making the LDL smaller and denser. This causes a shape change which exposes new regions on the surface of the LDL.

The exposed regions more easily stick to artery walls, helping to build fatty plaques. As the fatty plaques accumulate, they narrow the arteries leading to a reduced blood flow. Eventually they may rupture, triggering a blood clot that causes a heart attack or stroke.

The discovery also helps to explain why metformin, a widely prescribed type 2 diabetes drug, also appears to reduce the risk of heart disease.

Metformin is known to lower blood sugar levels, and might work by blocking the transformation of normal LDL to the more sticky MGmin-LDL.

Dr Naila Rabbani, who led the study, said: "We're excited to see our research leading to a greater understanding of this type of cholesterol, which seems to contribute to heart disease in diabetics and elderly people.

"Type 2 diabetes is a big issue – of the 2.6 million diabetics in the UK, around 90 per cent have type 2. It's also particularly common in lower income groups and South Asian communities.

"The next challenge is to tackle this more dangerous type of cholesterol with treatments that could help neutralise its harmful effects on patients' arteries."

The study was published in the journal Diabetes.

This article was published on Fri 27 May 2011