Although inflammation is meant to be protective, a disproportionate response can be damaging to the body - for example, causing potentially life-threatening symptoms seen in severe cases of influenza infection. It also plays a crucial role in a number of autoimmune diseases such as rheumatoid arthritis. Although scientists suspected that it would also be likely to increase risk of cardiovascular disease, until now little evidence existed to confirm or disprove this suggestion.
"The common view is that inflammation promotes the development of heart disease - we've shown that the truth is clearly more complicated," says Daniel Freitag, PhD, lead author of the study, University of Cambridge.
The finding is one of the outcomes of research using a powerful new genetic tool that mimics the behavior of certain anti-inflammatory drugs. The technique allows researchers to study the effects of inhibiting interleukin-1, a master regulator of inflammation, on a range of different outcomes not yet investigated in clinical trials.
Interleukin-1 plays a central role in regulating the body's inflammatory response, setting off a cascade of signals within the body against infection and other damage. Certain drugs, such as anakinra, reduce inflammation by blocking interleukin-1. This action also occurs naturally in individuals who carry particular genetic variants.
Although anakinra has been tested in clinical trials and shown to be effective in treating symptoms of rheumatoid arthritis, there has been little research into its effect on coronary heart disease. This is, in part, because of the complexity of studying heart disease and the number of individuals and length of study required in order for an effect to become apparent. By studying naturally-occurring interleukin-1 inhibition, the researchers have been able to infer that the drug could potentially elevate the risk of coronary heart disease and abdominal aortic aneurysms.
"It is important to remember that this is not a study of an anti-arthritis drug but a gene that can mimic its effects," says professor Peter Weissberg, MD, Medical Director, British Heart Foundation, which helped fund the study. "The effects of a gene are lifelong, whereas a drug only affects a person while it is being taken."
He adds, that, nevertheless, the study suggests patients who are prescribed anakinra should have their cardiovascular risk factors carefully managed by their physician.
[Source: University of Cambridge]