Elisabetta Bugianesi et al. undertook this study to elucidate the interplay between macrophage activation, insulin resistance in target organs and tissues and hepatic damage.In 40 non-diabetic patients with biopsy-proven NAFLD the authors assessed endogenous glucose production, glucose clearance and indexes of insulin resistance in the adipose tissue, and macrophage activity, and hepatic expression of CD163.
This study may suggest a different perspective in considering macrophage activation in the liver of patients with NAFLD, along with (and possibly in addition to) macrophage activation in the adipose tissue.
It is likely that the overflow of free fatty acids to the liver is one of the main metabolic sources of activation of resident hepatic macrophages in patients with NAFLD and can provide one of the mechanisms linking adipose tissue insulin resistance and liver fibrosis in these patients. This is the first study to confirm in humans and in vivo a major mechanism of progression to NASH, that has been previously postulated in animal models.