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Feature: Omega-3 research sheds light on inflammation trigger
Paving the way for novel therapeutics that target inflammation more effectively
Scientists at the University of Birmingham have discovered that omega-3 fatty acids from dietary fish oil can block a previously unknown step in blood vessel inflammation, which contributes to heart disease. Their study could pave the way for novel therapeutics that target inflammation more effectively.
We’ve all heard that eating oily fish is good for us. But little is known about the normal cellular mechanisms by which omega-3 fatty acids produce their protective effects.
Only recently, researchers discovered that inflammation plays a vital role in the development of angina and heart attack. Untangling the processes by which normally-protective white blood cells can cause inflammatory damage in our arteries could lead to new ways to protect the heart and circulation.
A finger on the trigger
In a new approach, funded by BBSRC and the British Heart Foundation, Dr Ed Rainger and colleagues from the Centre for Cardiovascular Sciences at the University of Birmingham, along with researchers from the Universities of Southampton and Cardiff, have conducted a study to observe the effects of ‘normal’ physiological levels of both omega-3 and -6 fatty acids on early inflammatory processes, which are regulated by endothelial cells lining blood vessels.
The team found evidence that PGD2, a major metabolic product of omega-6 fatty acids, is an essential signal for the migration of neutrophils – a type of white blood cell – to cross the endothelium from the blood into tissue. Importantly, the team also discovered that this trigger could be blocked when endothelial cells had been previously ‘fed’ with the omega-3 fatty acid EPA.
Benefits for heart and circulation health
“These findings are very significant,” explains Dr Rainger. “They support the idea that omega-6 fatty acids are pro-inflammatory, and are indeed required to sustain a normal inflammatory response, without which we would be prone to serious infection and tissue damage. However, they also provide mechanistic evidence that supports the anti-inflammatory role of omega-3 fatty acids. Understanding these mechanisms could help us control the exaggerated or unwanted inflammatory responses associated with disease”.
Associate Medical Director of the BHF, Professor Jeremy Pearson, said, “This research sheds light on how fatty acids found in fish oils can have beneficial effects on heart and circulation health”.
The identification of these novel mechanisms by which inflammation is regulated may allow researchers to develop new therapies to intervene when the process of inflammation becomes pathological rather than physiological.
Balancing health and nutrition
Omega-3 and omega-6 fatty acids are required in a number of essential metabolic processes. However, these polyunsaturated fatty acids can only be synthesised from essential fatty acids found in the diet.
The omega-6 fatty acid, arachidonic acid is synthesised from linoleic acid. While the omega-3 fatty acids eicospentaenoic acid, EPA, and docosahexaenoic acid DHA are synthesised from a-linolenic acid. Both linoleic and a-linolenic acid are derived from plant oils. Importantly however, both EPA and DHA are also available directly from other dietary sources, e.g. the flesh of oily fish, and therefore may be an important supplement to the metabolic production of the essential fatty acids.
Many nutrition experts believe that imbalances in omega-3s and -6s may explain the rise of diseases such as asthma, coronary heart disease, many forms of cancer, autoimmunity and neurodegenerative diseases, all of which are believed to stem from inflammation in the body. It is possible that diets poor in essential fatty acids overall could be improved by supplementing directly with omega-3 fatty acids and this may redress the imbalance between the inflammatory and anti-inflammatory influences of these polyunsaturated fats.
This article is based on research published recently in PLoS Biology, 7: e1000177 (August 2009)
Dr Ed Rainger, University of Birmingham
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