How does this relate to the endothelium?
Atherosclerosis (ath-er-o-skle-RO-sis) is the build-up of fatty deposits called plaque on the inside walls of arteries. Plaque is a combination of cholesterol, other fatty materials, calcium, and blood components that stick to the artery wall lining. A hard shell or scar covers the plaque. As plaque builds up in an artery, the artery gradually narrows and can become clogged. As an artery becomes more and more narrowed, less blood can flow through. The artery may also become less elastic.
Most plaque buildup occurs in medium to large arteries and many investigators suspect that this buildup begins with changes in the endothelium, the innermost layer of the artery. These changes cause white blood cells to stick to the endothelial cells, weakening the barrier between the endothelium and the other layers of the artery. This allows fats, cholesterol, calcium, platelets, and cellular debris to accumulate in artery walls. In turn, this accumulation can stimulate other arterial wall changes that lead to the additional thickening of the endothelium and the formation of plaques.
Plaques have various sizes and shapes. Some plaques are unstable and can rupture or burst. When this happens, it causes blood clotting inside the artery. If a blood clot totally blocks the artery, it stops blood flow completely. This is what happens in most heart attacks and strokes. There are usually no symptoms, such as pain, until one or more artery is so clogged with plaque that blood flow is severely reduced.
All of this takes time. In fact, atherosclerosis is a slow, progressive condition that often starts in childhood. But by age 65 it affects one out of every two adults. Scientists at the National Heart, Lung, and Blood Institute are studying why and how the arteries become damaged with age, how plaques develops and changes over time, and why plaques can break open and lead to blood clots. In particular, they have identified the age-related changes in the arteries as the major catalyst for the development of atherosclerosis. Research indicates that improving the health of the endothelium might delay or prevent these age-related vascular changes, reduce the risk of atherosclerosis, and even reverse or cure atherosclerosis.
There are a number of other risk factors, such as smoking, high blood pressure, and high blood cholesterol that can be modified with a diet, exercise, and other lifestyle changes. The more risk factors you have, the more likely it is that you have atherosclerosis. Talk with your health care provider about your risks for atherosclerosis and cardiovascular disease and what you can do to reduce them.