How damage from hyperglycaemia leads to microvascular complications

Cells need glucose to function, and some, such as those in blood vessels, kidneys and nerves, can pick up glucose directly from the blood. When blood glucose levels are high, the interiors of these cells become flooded with the sugar, causing failures in several processes such as enzyme production, structure repair and nutrient transport. This leads to cell damage and malfunction, leading to microvascular complications.

Other cells, such as those in the muscles and liver, need insulin to help glucose move across the cell membrane. If blood sugar is high and insulin low, the movement of glucose is slow, and so the cells are spared the damage described above. However, the liver in particular is likely to release more glucose in response to low insulin levels, which increases the amount of fats in the bloodstream. This causes other problems, particularly with regards to the larger blood vessels.