Science
Antibodies may be key to pre-empting heart attacks
Researchers believe that testing levels of certain antibodies in the blood will soon help to identify patients with ‘vulnerable’ or life-threatening plaques in heart arteries. New research, funded by us and in press with JACC: Cardiovascular Imaging, found that people with high levels of a particular type of antibody have lower levels of dangerous fatty plaque in their arteries, leading to a reduced risk of heart attacks.
Antibodies are proteins produced by the body’s immune system as a defence against bacteria, viruses and other dangers. In the patients studied the immune system is triggered to produce antibodies against a type of cholesterol found in dangerous plaques.
The antibody test is already easily carried out in the lab but needs refining before it can be used clinically. The researchers say that in three to four years it could be used nationwide to assess a person’s risk of developing heart and circulatory diseases.
"Improving accuracy to save lives"
Dr Adam Hartley, a researcher at the Khamis Laboratory, National Heart and Lung Institute, Imperial College London, and one of the lead authors of the study, said: “The use of an antibody blood test as an indicator of levels of dangerous plaque could certainly improve the accuracy of doctor’s risk predictions.
"This simple, quick blood test could be a new way of spotting dangerous atherosclerosis, a condition that many people do not know they have. This could in turn improve treatment decisions and save lives.”
Atherosclerosis is the build-up of fatty plaques in the walls of the arteries. If a plaque ruptures, a deadly blood clot can form and block the blood supply to the heart or brain. Atherosclerosis is common and causes most heart attacks and strokes, but most people do not know they have it.
Plaques can be detected using CT scans, and recent imaging studies have helped researchers better identify hard-to-spot ‘vulnerable’ plaques that are more likely to rupture. But CT scans are too expensive and time consuming for widespread use identifying people with dangerous plaques. A quick and easy blood antibody test offers a possible alternative.
To understand the link between degree of atherosclerosis shown on CT scans and blood antibody levels, Dr Ramzi Khamis and his team at the National Heart and Lung Institute, Imperial College London, used anonymised blood samples and CT scans from one of these studies, the SCOT-HEART trial.
Researchers used blood samples from SCOT-HEART to test 830 participants’ natural levels of an antibody called anti-MDA-LDL, which binds to a type of cholesterol found in plaques that are more likely to rupture. All participants in the trial also had a CT scan, which showed who had life-threatening plaques.
When they compared the blood test results and CT scans, the Imperial team found that people with the highest levels of this antibody had the lowest amount of all plaque types, particularly the most dangerous plaques, in their heart arteries. Meanwhile, the third of patients with lower antibody levels had more life-threatening plaque. The SCOT-HEART researchers had already shown that the people with more of this type of plaque were more likely to experience a serious heart or circulatory problem, such as a heart attack.
Opportunity for treatment
The team are now working to improve the specificity of the antibody test results so that it can be used clinically. They hope these improvements will allow the test to be incorporated into risk calculators that doctors use to assess people’s future risk of developing heart and circulatory diseases.
As well as being used to predict the presence of plaque, the researchers hope that the antibodies could provide an opportunity to treat atherosclerosis. The team are now testing ways to boost the body’s production of this antibody as it’s possible that using therapies to raise levels of the antibody will help to reduce levels of dangerous plaque.
Professor James Leiper, our Associate Medical Director, said: “Atherosclerosis causes more heart attacks and strokes than any other condition. This collaborative study offers hope for new ways to try and prevent these devastating incidents by identifying those patients at most risk.
“The discoveries described in this paper open a promising potential new route to treatment, but it is early days. Further investigations into these antibodies will reveal much more about whether they can be produced and used therapeutically.”