Diabetes

Diabetes (or diabetes mellitus) describes conditions in which levels of glucose in the blood are abnormally high. Glucose is an energy source that comes from food. It is stored in the liver and muscles in a form called glycogen.

It is critical for health that the level of glucose is tightly controlled in the blood. Without enough glucose, organs cannot function properly, but too much glucose can cause organ damage.

Normally blood glucose levels are tightly controlled by two hormones released by the pancreas:

• Insulin: decreases blood glucose when it is high, such as after a meal, by increasing glucose uptake by cells and blocking the glucose release from the liver.
• Glucagon: increases blood glucose when it is low, such as after exercise, by opposing the actions of insulin and releasing glucose from the liver.

Blood glucose can be elevated for a variety of reasons. The three most common types of diabetes in Australia are:

• Type 1 diabetes: caused by immune destruction of the insulin-producing cells in the pancreas.
• Type 2 diabetes: a condition in which the body does not respond appropriately to its own insulin, called ‘insulin resistance’, together with gradual loss of beta cell function and evidence of low-grade inflammation.
• Gestational diabetes is a form of insulin resistance that occurs during pregnancy. For more information about this and other rarer forms of diabetes, visit Diabetes Australia.

People with diabetes are at risk of short-term and long-term health problems caused by high blood glucose. People with diabetes can experience immediate symptoms of very low or high blood glucose.

High levels of glucose can cause immediate and serious problems for people with diabetes. A lack of insulin, particularly in type 1 diabetes, can rapidly lead to a serious condition called diabetic ketoacidosis. This is caused by cells switching away from glucose as an energy source, instead metabolising fatty acids, a process that generates toxic byproducts.

In the long-term, consistently high levels of blood sugar caused by diabetes can cause damage to many organs. This can lead to serious health problems including:

• Kidney disease (diabetic nephropathy)
• Eye disease and blindness (diabetic retinopathy)
• Nerve damage (diabetic neuropathy)
• Damage to blood vessels, which together with nerve damage can lead to serious problems in the hands and feet
• Heart disease and stroke.

Good control of blood sugar greatly reduces the risk of diabetic complications.

For more information, and support for people with diabetes please visit Diabetes Australia.

Insulin is a critical treatment for people with type 1 diabetes, and for some people with type 2 diabetes. Currently, insulin cannot be given as a tablet, but must be injected.

Different forms of insulin are available, which act over different time frames. ‘Short-acting’ insulin rapidly decreases blood glucose, so is best taken after a meal. ‘Long-acting’ insulin can control blood glucose levels over longer periods. Combinations of different insulin types offer people with diabetes the best opportunity to maintain healthy blood glucose levels.

Our structural biology researchers have revealed how insulin uses the insulin receptor to bind to the surface of cells. They hope this discovery could lead to the development of new types of artificial insulin that could be given without injections. Understanding how insulin functions may also contribute to more stable, longer-acting forms. The goal of this research is to improve the control of blood glucose in people taking insulin to treat diabetes.