Activation of AMPK improves inflammation and insulin resistance in adipose tissue and skeletal muscle from pregnant women

Gestational diabetes mellitus (GDM) is characterised by maternal peripheral insulin resistance and inflammation. Sterile inflammation and bacterial infection are key mediators of this enhanced inflammatory response. Adenosine monophosphate (AMP)-activated kinase (AMPK), which is decreased in insulin resistant states, possesses potent pro-inflammatory actions. There are, however, no studies on the role of AMPK in pregnancies complicated by GDM. Thus, the aims of this study were (i) to compare the expression of AMPK in adipose tissue and skeletal muscle from women with GDM and normal glucose-tolerant (NGT) pregnant women; and (ii) to investigate the effect of AMPK activation on inflammation and insulin resistance induced by the bacterial endotoxin lipopolysaccharide (LPS) and the pro-inflammatory cytokine IL-1 beta. When compared to NGT pregnant women, AMPK alpha activity was significantly lower in women with GDM as evidenced by a decrease in threonine phosphorylation of AMPK alpha. Activation of AMPK, using two pharmacologically distinct compounds, AICAR or phenformin, significantly suppressed LPS- or IL-1 beta-induced gene expression and secretion of pro-inflammatory cytokine IL-6, the chemokines IL-8 and MCP-1, and COX-2 and subsequent prostaglandin release from adipose tissue and skeletal muscle. In addition, activators of AMPK decreased skeletal muscle insulin resistance induced by LPS or IL-1 beta as evidenced by increased insulin-stimulated phosphorylation of IRS-1, GLUT-4 expression and glucose uptake. These findings suggest that AMPK may play an important role in inflammation and insulin resistance.