Blood Test Anticipates Diabetes 10 Years in Advance

British researchers have reported that it may be possible to identify people who are going to develop Type 2 diabetes even before symptoms occur. If the test can be verified, it might be possible to screen people who are at higher-than-normal risk of developing diabetes and intervene before symptoms, and the broad spectrum of complications that accompany them, occur.

The test can identify around half of people who will develop Type 2 diabetes, said researchers. It works by detecting levels of a genetic molecule in their blood.

The same molecule, called a microRNA (MiR), could help pinpoint sufferers at high risk of heart and artery disease.

The test can also distinguish between those who will and will not go on to develop some of the complications of diabetes caused by damage to blood vessels, such as heart attack, stroke and poor circulation.

Dr. Manuel Mayr, lead scientist, King's College London, UK, said he expected the MiR test to be used in conjunction with conventional methods. It is likely to cost around $3. Its biggest advantage was that it directly assessed the damage diabetes was causing to blood vessels.

"It's very important for doctors to define those diabetic patients that are at the highest risk of developing cardiovascular complications," said Dr. Mayr. "We hope that this new class of blood markers may give additional insight that we're currently not getting from other clinical tests."

Being able to identify which people with diabetes are particularly at risk of having a heart attack or stroke should allow doctors to begin early treatment with cholesterol and blood pressure-lowering drugs and target it at those who are most likely to benefit.

One type of micro-RNA, known as MiR-126, protects blood vessels from damage.

Healthy blood vessel cells are able to release substantial MiR-126 in to the blood stream. However, when they become damaged, they need to keep the MiR-126 for themselves and shed less in to the blood.

In a study of 822 residents, they identified five specific microRNAs whose concentration in blood was abnormally low in people with diabetes and in those who subsequently went on to develop the disorder. One in particular, microRNA 126, was among the most reliable predictors of current and future diabetes, they said. MicroRNA 126 is known to help form new blood vessels and regulate their maintenance and its loss may be an indicator of blood vessel damage and cardiovascular disease. They subsequently showed that levels of the marker were also reduced when large amounts of sugar were given to mice with a genetic propensity to develop diabetes.

The risk of having a heart attack is between two and five times greater in people with diabetes. Around 15 percent of heart attacks are due to diabetes.

Professor Jeremy Pearson, associate medical director at the British Heart Foundation, which funded the research, said, "This is important because right now there is no quick and simple way to monitor blood vessel health."

"Problems go unnoticed until symptoms appear, and the first symptom could be as serious as a heart attack."

Circulation Research, Sept. 2010