A CHEAP and easy blood test that detects the earliest signs of furry arteries could help reduce the number of people dying from heart disease.
One in three people will die from heart problems before the age of 70. At the moment, the best method of diagnosis is an angiogram, which involves injecting a contrast-enhancing chemical into individual blood vessels and X-raying them. It鈥檚 expensive, time-consuming and risky. But now researchers have developed a test that needs only a few drops of blood.
The technique looks at the metabolites in blood, and was developed jointly by researchers from Imperial College, London, pharmaceuticals company GlaxoSmithKline in Stevenage, Papworth NHS Trust in Cambridge and Cambridge University. In people with heart problems the body is fighting against disease, says Jeremy Nicholson of Imperial College, and this will show up in the concentration of metabolites 鈥� small molecules such as fatty acids that are formed or used in metabolism.
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To examine the molecules, blood plasma is placed in an NMR (nuclear magnetic resonance) machine. This subjects the sample to a magnetic field and a quick blast of radio waves, which makes the protons in the nuclei of molecules in the blood vibrate. As they vibrate, the protons send out their own radio waves, the frequencies of which depend on the kind of molecule they are in, leading to a unique 鈥渇ingerprint鈥� of the metabolites present.
Because there are so many different metabolites in blood, it is hard to interpret the signals emitted. So the group developed a pattern-recognition program to extract useful information from the signals. First they had to teach the program to identify the subtle differences between 鈥済ood鈥� blood and 鈥渂ad鈥� blood. They did this by feeding in NMR data from healthy people and those with atherosclerosis 鈥� the furring of arteries that can lead to a heart attack. The program was then used to test blood samples, with impressive results. The team found it correctly identified people with early stage coronary heart disease 90 per cent of the time (Nature Medicine, DOI: 10.1038/nm802). By feeding in more data they should further improve the program鈥檚 accuracy.
The team claims the ease of the technique, simply running a blood sample through an NMR machine, could revolutionise heart disease diagnosis. 鈥淚n 2 to 3 years, these could be in any local hospital,鈥� says George Tranter at Imperial College. That could make it possible to diagnose heart disease much earlier than is possible now, perhaps even before symptoms appear.
Nicholson adds that measuring metabolites, a field called metabonomics, could also be used to diagnose many other conditions, such as bone and brain diseases and cancer. The team has results awaiting publication in the journal Science that show they can detect a common bone disease.
