Atherosclerosis is a form of hardening of the blood vessels, caused by fatty deposits and local tissue reaction in the walls of the arteries. Blood supply beyond the affected parts of the artery is usually compromised by the narrowing and, sometimes, occlusion of the artery. The deposits, called plaques, may rupture with disastrous consequences. Diabetes mellitus is a documented high risk factor for the development of atherosclerosis. Heart disease and stroke, arising mainly from the effects of atherosclerosis, account for 65 percent of deaths among diabetics. Other complications of diabetes, such as blindness, gangrene and kidney disease, all have some deficiency of blood supply in their genesis.
Atherosclerosis in Diabetes
Normal blood vessels have an inner lining, called endothelium, that keeps blood flowing smoothly by producing local Nitrous oxide (NO). NO serves to relax the smooth muscles in the walls of the vessels and prevent cells from sticking to the walls. A disruption of this mechanism is thought to be at the heart of the increased formation of plaques in diabetes. High blood sugar, elevated fatty acids and triglycerides leads to stickier walls, encouraging the attachment of cells that produce local tissue reaction. The local tissue reaction further traps floating particles and different blood cells, heaping up and hardening the vessel walls.
Insulin stimulates the production of NO by the cells lining the blood vessels. In diabetics who are resistant to the actions of insulin, this stimulatory effect is lost, resulting in increased tendencies towards plaque formation.
In the presence of raised blood sugar and resistance to insulin, the lining cells of the blood vessels not only reduce production of NO, they also increase the production of substances that constrict the blood vessel, further encouraging plaque formation. The smooth muscles of the blood vessels are also hyperactive in diabetes.
Platelets and clotting factors are also affected by the high blood sugar, fatty acids and free radicals in diabetes. The blood cells are much stickier and the factors that inhibit clots do not work well under the peculiar circumstances of diabetes.
Atherosclerosis can affect any blood vessel with disastrous effects to the organs supplied by the vessel involved. When it involves the arteries supplying the heart, it leads to Coronary Artery Disease (CAD). This usually results in cases of angina or heart attacks. Involvement of other arteries leads to Peripheral Artery Disease (PAD). When it involves the arteries of the brain, the condition can result in strokes.
Adequate treatment of diabetes with lifestyle modifications has a highly positive impact, restoring normal function and reducing plaque formation.