A study is conducted involving persons with LDL cholesterol levels above 160 mg/dL. They are found to have increased oxidized LDL deposited in their arteries. As a consequence, the arterial lumen, particularly at branch points, is decreased in size. Which of the following is the most likely pathologic change that develops initially in these areas of arterial narrowing?
The initial response of an arterial wall to injury is intimal thickening with neointimal smooth muscle cell proliferation and production of an increased intimal extracellular matrix. Note that "injury" can be caused by inflammation, immune reactions, and toxins as well as the local physical trauma from hypertension and abnormal flow. The trauma does not produce immediate injury with endothelial cellular disruption, but a response of endothelial dysfunction that signals smooth muscle cell migration. This process takes years to show changes of vascular narrowing. As atheromatous plaques progress, there is participation by lymphocytes producing cytokines, as well as monocytes that are transformed into macrophages that accumulate lipid to evolve into foam cells. Eventually, plaque disruption may incite platelet aggregation.
Endothelial cell disruption
Intimal thickening
Lymphocytic infiltrates
Platelet aggregation
Blood Vessels