Two types of Diabetes
Diabetes is described by the body’s inability to produce insulin, type 1 diabetes, or to respond to insulin, type 2 diabetes. Type 2 diabetes represents 90 % of all diabetes patients and is characterized by defects in insulin sensitivity leading to hyperglycaemia and the disruption of normal glucose metabolism.
The major function of insulin is to take care of nutrients entering into the blood circulation during feeding. One of these components, glucose, is rapidly being taken care of after feeding and transported into different cells for immediate or later use. It is very important to maintain a very precise blood glucose level. High levels will damage cells (organs) and to low level will disable normal cell and body function.
Type 2 diabetes
Type 2 diabetes is a complex multi-factorial disorder. Understanding of how the disease develops increases, and environmental factors like over-consumption of food and lack of exercise leading to obesity, is found to be a major risk factor. Glucose, or sugar, enters the bloodstream after a meal and the body's normal response is to release insulin from the pancreas in response to rising blood glucose levels. Insulin then acts as a key, opening cells to allow glucose in from the bloodstream and to be stored in the form of “harmless” glycogen. The efficiency of the insulin to remove excess glucose from outside and inside the cells is crucial for not inflicting oxidative stress causing cellular damage. Once inside the cells, the glucose can additionally be turned into energy that the body needs to function normally.
Type 2 diabetes develops when muscle, fat and liver cells fail to respond normally to insulin. This failure to respond is called insulin resistance. The pancreas initially compensate for this insulin resistance by increasing insulin output. Over time, pancreatic cells "burn out" and become unable to produce enough insulin to maintain normal glucose levels. Eventually, type 2 diabetes may thus develop into a type 1 like state.
High blood glucose levels causes tissue damage by increased glycation of proteins and elevated ROS production, in particular through increased NAD(P)H-oxidase activity. Initially this may lead to micro-vascular impairment as in the kidneys (nephropathy), eye (retinopathy) and nerves (neuropathies). On prolonged poorly controlled hyperglycaemia macro-vascular damage may develop resulting in severe cardiovascular problems like infarctions.