Combination of metformin with sodium selenite induces a functional phenotypic switch of human GM-CSF monocyte-derived macrophages.

Objectives: We evaluated the effects of metformin (Met, 1,1‑dimethylbiguanide hydrochloride) combined or not with sodium selenite (Ss, NaSeO) on the functional activities of LPS-activated GM-CSF monocyte-derived macrophages (GM-MDM).

Materials And Methods: Human GM-MDMs from three healthy donors were treated with Met or Ss alone, or with the combination of Met and Ss, and assayed for various biological activities and cytokines expression.

Results: Met alone and Ss alone had significantly different effects on phagocytosis and killing capacities and IL-β production, but had similar effects on the downregulation of inducible nitric oxide synthase (iNOS) activity, relative nicotinamide adenine dinucleotide reduced (NADH) dehydrogenase (Complex I), intracellular free calcium ions (Ca), and on the upregulation of arginase activity.