Scientists have uncovered the physiological mechanics underlying inflammation and obesity by tracking the actions of ‘guardian immune cells’ in response to changes in diet.
They believe their work may herald a new era of research now that they have new therapeutic targets to prevent and control obesity-related inflammation and metabolic disease.
The scientists, led by Professor Lydia Lynch of Trinity College Dublin and Harvard Medical School, discovered that special guardian immune cells are unable to function properly once obesity is established, which results in severe inflammation and metabolic dysfunction.
These guardian immune cells, called Adipose Type One Innate Lymphoid Cells, or ILCs, were only recently discovered by Professor Lynch and her team. They live in our fat, and are charged with maintaining a delicate balance of our immune systems.
In other cases, ‘natural killer’ cells -- which are part of the ILC family -- recognise specific proteins on the surfaces of healthy immune cells that act a little like passwords; if a cell possesses the password, the natural killer cells let it go about its normal business. Natural killer cells typically kill cancer cells, which lack the required password, whereas the healthy immune cells don’t.
However, uniquely in fat, the ILCs do not recognise these passwords and instead attack the healthy macrophages.
Professor Lynch’s work was recently published in the international journal Immunity. The findings confirmed that ILCs are very responsive to diet, which underlines the role that healthy eating plays in affecting our immune systems. For example, after eating a fatty diet for just five days, ILCs home in on fat cells; likewise, their numbers in blood and fat go the other way when weight is lost.