Accelerated Atherosclerosis in Diabetes
Heart disease is the most important cause for morbidity and mortality in diabetics. Cardiovascular disease accounts upto 80% of deaths in type 2 diabetes. Infact diabetics have 3 – 7.5 times greater incidence of deaths from cardiovascular causes when compared to nondiabetic population.
Atherosclerosis is the main cause of heart problems in diabetics which is influenced by multiple factors.
- Studies indicated that atherosclerotic coronary artery disease begins in chidhood.
- Many autopsy studies revealed – Serum cholesterol concentration and smoking has lot of impact on early stages of atherosclerosis.
So educate your children and increase their awareness on healthy diets, excersice, avoiding smoking!
What is Atherosclerosis?
The inner layer of the blood vessels is called ‘intima’. Deposition of lipid in the intima causing plaque like lesions is called ‘atherosclerosis’.
All sizes of blood vessels are affected by this. If medium sized blood vessels like coronary arteries (vessels that supply the hear muscle) are affected, heart is involved. If small vessels like eye, kidney are involved, person will get retinopathy and nephropathy.
Why Atherosclerosis is Common in Diabetes
Abbrviation for "Advanced Glycation End products". AGEs are formed by nonenzymatic reaction between glucose and amino groups of proteins, lipids and nucleic acids. Normally they are formed in the body at slow pace. But in diabetes, more the reducing sugar, glucose is available, AGEs are formed in accelerated fashion.AGEs has effects like altering endothelial, mesangial and macrophage cellular functions, modify LDL cholesterol so it oxidized and deposited within vessel walls causing atheromas, generation of reactive oxygen species.
- Free radicals:
Cellular oxidation of glucose generates oxygen radicals which leads to oxidation of lipoprotiens. LDL is oxidised and this oxidized LDL is trapped in the muscle cells of the vessel walls, macrophages contributing the atheroma formation.
Fat soluble vitamins like vitamin A and E and water soluble vitamin like Vit C are good antioxidants that fight against oxygen radicals.
- Altered matrix proteins:
As told above AGEs interact with extra cellular proteins. These causes the cross linking of the same proteins. For example crosslinking of collagen type I, decreases their elasticity and predispose to the endothelial injury.
And these abnomal crosslinked proteins resists digestion and deposited making the vessels stiff.
- Altered endothelium, smooth muscle cells and macrophages:
Circulating plasma proteins like LDL are modified by the AGEs. These modified proteins bind to the macrophages and smooth muscle cells to generate chemical substances called cytokines. These cytokines cause inflammation and damage to endothelial cells. These AGE modified proteins also increase permeability of the endothelium and procoagulant activity of macrophages and endothelial cells.
All the above factors are enhanced in diabetics more so in long standing diabetics like type 2.
Other conventional factors like altered lipoprotein levels in blood,associated hypertention, increased coagulant state also damage the endothelium leading to increased permeability, increased deposition of fat in blood vessels leading to atheroma formation.