A new hypothesis: possible mechanisms in the involvement of the increased plasminogen activator activity in branching regions of the aorta in the initiation of atherosclerosis.

Branching regions of the aorta are predilection regions for atherosclerosis. The intima in the branching regions of the normal aorta shows a constantly increased plasminogen activator activity from early life. At these areas, the endothelium is also damaged, it shows increased permeability, etc. The constantly increased plasminogen activator activity (local plasmin production) might play a protective role or on the might participate in the initiation of atherosclerosis at the branching regions through a number of proved or suggested mechanisms. No matter what the actual role of the locally increased plasminogen activator activity in the initiation of atherosclerosis is, the role of the fibrinolytic system in the progression of the atherosclerotic lesion seems to be clear. There is an accumulation of evidence that the impaired fibrinolytic activity in atherosclerotics participates in the progression and the complications of the disease.