Neutrophils help kick off insulin resistance in obesity

Experts have found that neutrophils play an important role in initiating the chronic inflammation that characterizes obesity-induced insulin resistance.

"These results are largely unexpected," said co-author Day Young Oh, from the University of California in San Diego, USA, in a press statement. "Although several immune cells have been established in the etiology of insulin resistance, the role of neutrophils in this process has remained unclear until now."

The team determined the time course of neutrophil infiltration in the adipose tissue of mice fed a high-fat diet (HFD), using fluorescence-activated cell sorting to identify adipose tissue neutrophils (ATNs).

As reported in Nature Medicine, there was a rapid increase in ATN levels after just 3 days of HFD feeding and ATN content remained elevated 12 weeks into the diet. Similarly, the expression of neutrophil elastase, a protease secreted by neutrophils, was significantly increased 3 days into the HFD and remained elevated after 12 weeks.

Consistent with these findings, neutrophil elastase activity was also significantly higher in the HFD mice after 12 weeks than it was in mice fed standard chow...