Monocyte-suppressing effect of high-dose metformin in fenofibrate-treated patients with impaired glucose tolerance

Abstract

Background: Fibrates were found to reduce cytokine release and low-grade inflammation in patients with impaired glucose tolerance. The aim of this study was to investigate whether these effects of fibrates may be potentiated by metformin treatment.

Methods: The study included 43 patients with isolated impaired glucose tolerance and normal plasma lipids who had been treated for at least 6 months with micronized fenofibrate (200 mg daily). These subjects were randomly assigned to 12 weeks' treatment with either high dose metformin (3 g daily in three divided doses) or placebo. Plasma lipids, glucose homeostasis markers, monocyte cytokine release and plasma C-reactive protein levels were determined before randomization and at the end of the treatment.

Results: Metformin treatment reduced plasma C-reactive protein levels and monocyte release of tumor necrosis factor-α and interleukin-6, as well as tended to reduce monocyte release of interleukin-1β and monocyte chemoattractant protein-1, which was accompanied by an improvement in insulin sensitivity.

Conclusions: Our results show that high-dose metformin produces monocyte-suppressing and systemic anti-inflammatory effects in fibrate-treated patients with isolated impaired glucose tolerance. This suggests that fibrate-metformin combination therapy may bring clinical benefits to impaired glucose tolerance patients at high cardiovascular risk.