Pathophysiology and complications of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is characterised by the combination of insulin resistance and insulin secretion deficiency, which intensify each other. T2DM is caused by genetic predisposition, physical inactivity, and obesity. Adipose tissue produces multiple adipocytokines, which are closely related to insulin resistance. A vicious circle is set up with the insulin resistance in adipose tissue, muscle and liver together with the resultant decreased glycolysis and glycogen synthesis and increased gluconeogenesis intensifying the insulin resistance. Consequences of the resulting hyperglycemia are microvascular complications such as retinopathy and damage to kidneys and the nervous system. Dyslipidaemia and hypertension are frequently associated with T2DM, but macrovascular complications must also be expected.