Researchers from Melbourne’s Walter and Eliza Hall Institute, and the RIKEN Institute in Japan have found they are able to “reverse” type 2 diabetes by lowering the inflammatory response that occurs in fat tissue.

The researchers, led by Dr Vasanthakumar, found regulatory T-cells (specialised immune cells also known as Tregs) help in maintaining insulin sensitivity and controlling inflammation in fat tissue. Tregs prevent immune response from getting too high and attacking the body’s tissue. In diseases like diabetes and rheumatoid arthritis the Treg numbers are reduced.

Type 2 diabetes results in decreased insulin sensitivity, meaning cells are less able to take up glucose from the bloodstream because cells no longer respond to the same levels of insulin. This is thought to be caused by low-level inflammation of fat tissue in obese people.

Fat tissue has been found to have its own type of Tregs that are lost when a person becomes obese. Furthermore fat tissue of obese people has a lower number of Tregs that leads to increased inflammation. This increased inflammation leads to insulin resistance and high blood glucose, both of which are symptoms of type 2 diabetes.
The discovery of IL-33, a hormone that boosts Treg populations in fat tissue has led to promise in treating type 2 diabetes. IL-33 returns the Treg levels of fat tissues treated with it to normal levels, reducing inflammation and lowering blood glucose levels. This was found to stop development of type 2 diabetes or even reverse it in preclinical models.

Dr Kallies, one of the lead researchers, highlighted the importance of ‘healthy’ fat tissue in maintaining health. “We can no longer think of fat tissue simply as energy storage…Fat tissue is increasingly being recognised as a crucial organ that releases hormones and regulates development. Keeping our fat tissue healthy is important for our general wellbeing”.

Three million people have diabetes in the UK with 90% of those thought to be suffering from type 2 diabetes. Type 2 diabetes is thought to be connected to a number of risk factors including age, weight and diet. Currently there is no cure for diabetes, and there can be a number of life threatening complications that come from the long-term effects of the illness. From this research it is hopeful treatments that mimic IL-33 could reduce obesity-related inflammation and type 2 diabetes.