A high-fat diet contributes to atherosclerosis by thickening arteries at the cellular level.
Atherosclerosis, which refers to the thickening and stiffening of the arteries, can lead to heart disease and stroke. It is caused by cholesterol, a tiny fat molecule found in the blood that the body uses to build cell membranes and some hormones.
Scientists are unsure how cholesterol causes atherosclerosis, but it is connected to the lipoproteins that carry the molecule around the blood. High levels of low-density lipoproteins (LDLs) in the blood is known to be a key risk factor for the condition.
A new study, the results of which were presented at the 63rd Biophysical Society Annual Meeting, looked at the role of a type of LDL, called oxidized LDLs to identify whether this may also be a key player in the development of atherosclerosis.
A team from the University of Illinois looked at the impact of a high-fat diet in mice. One group of animals was fed a well-balanced diet. The other was put on a diet that had been developed to mirror the levels of fat, protein and carbohydrate typically found on a fast food menu. The levels of LDLs and oxidized LDLs were measured.
The LDL and oxidized LDL concentrations found in the fast food mice were then applied to human endothelial cells in culture. Membrane tension and cytoskeleton stiffness measurements were taken using atomic force microscopy.
The mice that had been eating the high-fat diet quickly developed stiffer arteries. This occurred down to the layer of endothelial cells that surrounded the rodents’ blood vessels.
When the LDL and oxidized LDL concentrations found in the mice cells were calculated and applied to human endothelial cells in culture, they caused the cell membrane to thicken and become stiffer. This was compared to cells that had no lipoproteins added to them. What’s more, the effect was amplified when both LDL and oxidized LDL were added to the cells at the same time.
The study’s results suggest that changes in blood lipid levels caused by a high-fat diet can fundamentally disrupt the integrity of the endothelial cell layer.
“To our surprise, a very small amount of oxidized LDL dramatically changes the structure of the cell membrane for the worse,” says Manuela Ayee, who worked on the project with her colleague Irena Levitan.
“We think that the changes at the cell membrane level may allow the processes involved in atherosclerosis to begin.”
High-fat diet causes thickening of arteries down to the cellular level. Retrieved (April 2019) from https://www.eurekalert.org/pub_releases/2019-03/bs-hfd022119.php