β-Carotene, α-tocopherol and ascorbic acid: differential profile of antioxidant, inflammatory status and regulation of gene expression in human mononuclear cells of diabetic donors

BackgroundDiabetic patients are exposed to increased oxidative stress due to several mechanisms, mainly hyperglycaemia. Pathological processes, such as those in type 1 diabetes, include diminished activity of the antioxidant defense system(s) or excessive oxidative generation resulting in an oxidative/antioxidant imbalance and development of oxidative stress. MethodsThe purpose of this study was to evaluate the production of reactive oxygen species (ROS) (chemiluminescence) and reduction capacity (MTT dye reduction), the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, superoxide dismutase and catalase using quantitative reverse-transcriptase polymerase chain reaction, and the levels of cytokines [interleukin (IL)-6, tumour necrosis factor-, IL-8, IL-10 and IL-4] by sandwich enzyme-linked immunosorbent assay in mononuclear cells from non-diabetic and diabetic donors treated with a vitamin complex (ascorbic acid, -carotene and -tocopherol) in two different concentrations ([A]=ascorbic acid=0.08 mu M, -tocopherol=0.04 mu M, -carotene=0.0008 mu M and [20A]=ascorbic acid=1.6 mu M, -tocopherol=0.82 mu M, -carotene=0.016 mu M). ResultsConcentration [A] was antioxidant reducing ROS production, expression of NADPH oxidase subunits and pro-inflammatory cytokines while raising the expression of antioxidant enzymes and reducing pro-inflammatory cytokines in both groups. Concentration [20A] was pro-oxidant by raising ROS production, NADPH oxidase subunits and pro-inflammatory cytokines and reducing antioxidant enzymes and anti-inflammatory cytokines in the non-diabetic group but antioxidant in cells of type 1 diabetic patients by raising antioxidant enzymes and anti-inflammatory cytokines and reducing pro-inflammatory cytokines. ConclusionThe vitamin complex has a dual effect, pro-oxidant and antioxidant, being also dose dependent with different profiles of cells of non-diabetic and type 1 diabetic patients. Copyright (c) 2013 John Wiley & Sons, Ltd.