Scientists in Australia have discovered a potential cause of the link between obesity and diabetes.
The study showed that inflammation-causing cells in fat tissue could explain the high prevalence of diabetes in obese people. Researchers at the Walter and Eliza Hall Institute in Melbourne hope the discovery could lead to new anti-inflammatory treatments that prevent insulin resistance.
Professor Len Harrison said: "We have shown that insulin resistance in human obesity is closely related to the presence of inflammatory cells in fat tissue, in particular a population of macrophage cells."
Macrophages are white blood cells that develop from bone marrow and are the immune cells that normally protect against infections.
But the macrophages cells in obese people move into the fat tissue, causing them to inflame and release chemical messenger molecules called cytokines, which are used by immune cells to communicate.
Released cytokines can then cause cells to become resistant to the effects of the hormone insulin, leading to diabetes and heart disease.
For the first time, evidence has been found showing that macrophages in the fat tissue of humans are producing cytokines and stopping cells from responding to the presence of insulin.
The findings have been reported in the journal Diabetes.