title: Metformin reduces the expression of NADPH oxidase and increases the expression of antioxidative enzymes in human monocytes/macrophages culturedin vitro.
abstract: The treatment of diabetes and its complications is a key challenge for healthcare professionals. Accelerated atherosclerosis is associated with progressive diabetes, and it has been indicated that macrophages serve a crucial function in this process. Currently, the first-line treatment of diabetes is based on metformin, which is an inducer of AMP-activated protein kinase (AMPK) and belongs to the biguanide class of pharmaceuticals. It has been previously demonstrated that metformin exhibits more than just hypoglycemic effects. Therefore, the aim of the present study was to investigate thein vitroimpact of metformin on cell viability and the expression levels of nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase (p22phox), a major enzyme in reactive oxygen species generation, and the three antioxidative enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in monocytes/macrophages derived from 10 healthy volunteers. The effects of metformin were observed in the presence or absence of lipopolysaccharide (LPS), which was administered to induce oxidative stress. Furthermore, certain cells were treated with compound C, an inhibitor of AMPK, in order to determine the mechanistic role played by AMPK in the oxidative changes in the macrophages. Cell viability was evaluated using trypan blue and MTT assays. The mRNA and protein expression levels of p22phox and the various antioxidative enzymes were determined using polymerase chain reaction and western blot analysis, respectively. The results indicated that metformin, predominantly in LPS-pretreated monocytes/macrophages, reduced the expression levels of p22phox and increased those of SOD and GPx, but had only a minor effect on CAT levels. Therefore, metformin appears to alter the oxidative status of macrophages toward increasingly antioxidative activity, which may account for the pleiotropic effects observed during metformin treatment.
authors.affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Bułdak
authors.affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Łabuzek
authors.affiliation: Department of Physiology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Zabrze 41-808, Poland.
authors.forename: Rafał Jakub
authors.initials: RJ
authors.lastname: Bułdak
authors.affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Machnik
authors.affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Bołdys
authors.affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Basiak
authors.affiliation: Department of Internal Medicine and Clinical Pharmacology, School of Medicine in Katowice, Medical University of Silesia, Katowice 40-752, Poland.
authors.forename: Okopień
authors.initials: O
authors.lastname: Bogusław
keywords: macrophages; metformin; oxidative stress; reactive oxygen species