A high magnesium concentration in citrate dialysate prevents oxidative stress and damage in human monocytes in vitro

Background. The use of dialysis fluids (DFs) during haemodialysis has been associated with increased oxidative stress and reduced serum magnesium (Mg) levels, contributing to chronic inflammation. Since the role of Mg in modulating immune function and reducing oxidative stress has been demonstrated, the aim of this study was to characterize in vitro whether increasing the Mg concentration in DFs could protect immune cells from oxidative stress and damage. Methods. The effect of citrate [citrate dialysis fluid (CDF), 1mM] or acetate [acetate dialysis fluid (ADF), 3mM] dialysates with low (0.5mM; routinely used) or high (1mM, 1.25mM and 2mM) Mg concentrations was assessed in THP-1 human monocytes. The levels of reactive oxygen species (ROS), malondialdehyde (MDA) and oxidized/reduced (GSSG/GSH) glutathione were quantified under basal and inflammatory conditions (stimulation with lipopolysaccharide, LPS). Results. The increase of Mg in CDF resulted in a significant reduction of ROS production under basal and inflammatory conditions (extremelymarked in 2mM Mg; P<0.001). These effects were not observed in ADF. Interestingly, in a dose-dependentmanner, high Mg doses in CDF reduced oxidative stress inmonocytes under both basal and inflammatory conditions. In fact, 2mM Mg significantly decreased the levels of GSH, GSSG and MDA and the GSSG/GSH ratio in relation to 0.5mMMg. Conclusions. CDF produces lower oxidative stress than ADF. The increase of Mg content in DFs, especially in CDF, could have a positive and protective effect in reducing oxidative stress and damage in immune cells, especially under inflammatory conditions.