New light on diabetes and obesity

An international team, led by University of New South Wales, has discovered that a particular kind of cells, present in the fatty tissues of obese people, inhibits the production of insulin — the hormone which controls blood sugar levels.

Their study has pinpointed that the fatty tissues of obese people contains inflammation-causing cells, which lead to insulin resistance resulting in diabetes. According to the scientists, this findings may pave the way for new anti-inflammatory treatments for diabetes and related complications in obese people.

“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,” Prof Len Harrison, who led the team, said.

Macrophages, white blood cells derived from the bone marrow, are immune cells that normally respond to infections. In obese people, macro-phages move into the fat tissue where they cause inflammation and release cytokines, which are chemical messenger molecules used by all the immune cells to communicate.

Certain cytokines cause cells to become resistant to the effects of the hormone insulin, leading to diabetes. The findings provide the first evidence in humans that macrophages in fat tissue are producing cytokines that prevent cells from appropriately responding to presence of insulin, say the scientists.