Obesity leads to harmful activation of the immune system

9 February 2017        

Category: Research

Person standing on a scale

Obesity and a diet high in fat could lead to a harmful activation of the immune system, increasing a person’s risk of heart disease, according to a study funded by the BHF and published in the journal Cell Metabolism.

The link between obesity and inflammation

Previous research has shown that obesity increases blood pressure and cholesterol – both risk factors for heart disease.  

But now researchers believe obesity could also trigger an immune response that leads to inflammation in the coronary arteries, increasing a person’s risk of a heart attack. The findings could lead to new treatments that target this inflammation to reduce a person’s risk of heart disease. 

Higher levels of white blood cells

The researchers took blood samples from 1,172 lean, overweight or obese people. They found that a certain type of white blood cell, or T-cell was present in higher levels in obese people. 

When the team at Queen Mary University of London measured the fat distribution of these same people they also found that those carrying more fat around the middle (apple-shaped) had higher levels of these cells than those carrying fat on their thighs and bottom (pear-shaped).

Making heart disease worse

These T-cells are essential for the immune response as they protect the body from infections. However, they also cause inflammation which can make a number of cardiovascular diseases worse. For example, they can contribute to the build-up of fatty plaques in arteries in atherosclerosis, which can lead to a heart attack or stroke.

Linked to a high fat diet

Higher levels of these T-cells were also present in mice fed a high fat diet, leading the researchers to conclude that a high fat diet, which leads to obesity, is a cause of this harmful inflammation.

Developing new treatments

The researchers also identified a crucial molecule, found within our T-cells, which was responsible for increasing the number of this type of T-cell. They hope that by targeting this molecule it may be possible to develop treatments to reduce the harmful effect that obesity has on the heart.

Future breakthroughs

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