1. What happens inside a blood vessel to make a complication happen?

2. What is blood, and what does a blood vessel do?
Blood carries oxygen, nutrients and waste products around the body to get to the body part where they are needed.
Blood is contained in a blood vessel. There are 3 types of blood vessels which are arteries (pumps blood from your heart), veins (moves blood back to the heart) and capillaries (tiny blood vessels where oxygen, nutrients and waste products move into and out of cells in the body).
All of the organs in your body have cells and need oxygen or they will become damaged.
The blood vessels need to be healthy to be able to move enough blood around the body. If they are not this can cause problems with not having enough blood with oxygen and nutrients moving to where it is needed, and also not getting rid of waste products.

3. A blood vessel has an inside wall and an outside wall, which acts as a barrier to allow things to move in and out of the blood.

4. So, thinking of a blood vessel – why can high blood glucose levels cause damage?
A blood vessel has a wall which only lets certain things pass through it. This wall is a barrier and can become changed and weakened by high blood glucose levels. This allows fat cells (called cholesterol) move into the wall, and stay there. These fatty deposits cause the wall to become thickened and calcified or hardened.
When there is a lot of glucose inside the blood vessel wall it can stick to the wall and glucose can build up alongside fatty deposits. These can build up and narrow the space inside the blood vessel which causes reduced blood flow.
One of the types of blood cells are called platelets which cause blood clotting. Platelets are for when you cut yourself or have a wound that needs healed. The platelets stick together and stop bleeding. If blood glucose levels are high, platelets become more sticky and clump together more which happens inside the blood vessel wall and causes further blockage of the inside of the blood vessel.
High blood glucose levels damage the blood vessel walls further, and reduces the way oxygen and nutrients move in and out of the cells, so the cells and then the organs can become damaged.

5. Is it just high blood glucose which causes damage to a blood vessel?
No, although high blood glucose is the main factor. The other important things to think about are: blood cholesterol (or fat) levels, blood pressure, and the effects of smoking.

6. And what areas can the damaged blood vessels affect?
Stroke – in the brain
Eye disease called retinopathy
Heart disease and heart attacks
Delayed emptying of the stomach or gastroparesis
Kidney disease or nephropathy
Sex problems or sexual dysfunction
Foot disease or neuropathy