Atherosclerosis (2009)

Atherosclerosis is a life threatening disease that may have begun to develop during childhood This condition is a process in which deposits of fatty material called plaque, build up inside the walls of arteries reducing or completely blocking blood flow. In extreme cases, this disease can lead to a heart attack or a stroke. Risk factors for atherosclerosis include high blood pressure, high cholesterol, tobacco smoke, diabetes, obesity, and physical inactivity. Although the exact causes of atherosclerosis are not clear many scientists think it begins with damage to the inner wall of an artery called the endothelium over time, substances traveling in the blood such as cholesterol, fats, and cellular wastes products accumulate inside the damage area of the arterial wall chemical reactions occurring within the build up of material cause cholesterol molecules to oxidize This initiates an inflammatory response in which the endothelial cells at the damaged site release chemicals that signal a call for help In response, monocytes from the bloodstream travel to the damaged site stimulation from oxidized cholesterol converts the monocytes into macrophages the macrophages eat and digest the cholesterol molecules as a result of this process, the macrophages change into foam cells which accumulate to form plaque As the plaque increases in size, the arterial wall thickens and hardens. At the same time, smooth muscle cells within the arterial wall begin to multiply. Then, most of the smooth muscle cells move to the surface of the plaque. These cells contribute to the formation of a firm, fibrous cap, covering the plaque. Over time, the cap may erode and break open, releasing plaque into the bloodstream. The plaque can flow downstream and contribute to the formation of a blood clot which can stop blood flow. As a result, limited blood supply is available to the area surrounding the partially blocked artery degrading and potentially killing the neighboring tissue Significant damage in organs such as the heart or brain can result in a heart attack or stroke