Study finds bacterial culprit for clogged arteries in heart disease

A new study has found evidence that bacteria in the gut and oral cavity can contribute to the plaque build-up that occurs in arteries during the onset of atherosclerosis.
People with type 2 diabetes and those who are obese are more predisposed to cardiovascular complications, like atherosclerosis, than the rest of the population.
The new research suggests that the development and progression of atherosclerosis leading to plaque accumulation may be much more complex than it appears.
Scientists knew that blood lipids play a key role in the immune defence system and the vascular wound repair process.
It was previously assumed that the fatty molecules or lipids that aggregate to form this plaque originated from fat in the diet. However, there is increasing evidence that higher consumption of fat does not affect heart disease risk directly.
This new study suggests that there may be lipids of a different nature involved in plaque formation and the early development of atherosclerosis.
Researchers from the University of Connecticut analysed the constituents of a substance, known as atheroma, that contains a lot of fat that forms on the inside wall of an artery.
They found evidence of the interaction of lipids that come from a specific family of bacteria. The bacteria, called Bacteroidetes, make distinctive fats in higher amounts.
Bacteroidetes can colonise the mouth and gut, but do not usually cause harm or invade blood vessels. However, these lipids that they secrete can get through cell walls and into the bloodstream.
There are weight differences between Bacteroidetes lipids and other lipids that make up the atherosclerotic plaque, and immune cells involved in repairing vascular damage seems to react unfavourably to Bacteroidetes.
The immune cells on blood vessel walls recognise them as foreign. This may set off alarm bells and fuel inflammation and the thickening of parts of the artery wall, leading to further plaque formation.
The researchers also discovered that an enzyme in the body breaks bacterial lipids down into materials that assist inflammation.
In other words, Bacteroidetes lipids may directly impact the immune system, and they can spark even more inflammation when broken down by this enzyme.
Researchers now plan to carry out further studies to find out where the Bacteroidetes lipids accumulate in the vascular system and how much of it is found inside fatty deposits on the artery wall.
The findings were published in the Journal of Lipid Research.