The activation of NF-kB and AP-1 in peripheral blood mononuclear cells isolated from patients with diabetic nephropathy § Ji Sun Nam a,1 , Min Ho Cho a,1 , Geun Taek Lee b , Jong Suk Park a , Chul Woo Ahn a, *, Bong Soo Cha a , Sung Kil Lim a , Kyung Rae Kim a , Hun Joo Ha b , Hyun Chul Lee a a Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea b Ewha Womans University College of Pharmacy, Seoul, Republic of Korea 1. Introduction Chronic hyperglycemia is a major initiator of chronic diabetic complications which involves metabolic pathways [1,2]. The oxidative stress generated by hyperglycemia increases reac- tive oxygen species (ROS), which leads to the activation of various redox-sensitive cell signaling molecules and the production of cytotoxic materials. This is followed by cellular dysfunction and damage, and ultimately results in diabetic micro and macrovascular complications [1,3–5]. Mesangial expansion is a typical structural change in diabetic nephropathy [6,7]. Mesangial cells cultured in high glucose media exhibit high levels of mRNA encoding extra- cellular matrix (ECM) proteins and increased synthesis of these proteins [7], but the exact mechanism for this is unknown. The results of cell culture studies suggest that diabetes research and clinical practice 81 (2008) 25–32 article info Article history: Received 16 June 2007 Accepted 19 January 2008 Published on line 15 May 2008 Keywords: Diabetic nephropathy Oxidative stress NF-kB AP-1 TGF-b1 abstract We evaluated the role of oxidative stress in diabetic nephropathy by measuring intracellular reactive oxygen species (ROS) and redox-sensitive transcription factors in isolated periph- eral mononuclear cells (PBMC) in 66 diabetic patients with or without diabetic nephropathy (Groups III and II, respectively) and 49 normal controls (Group I). Stimulated ROS was significantly higher in Group III compared to Group II (increment of H 2 O 2 -induced ROS production: 21.8 Æ 2.2% vs. 11.1 Æ 2.0%; increment of PMA-induced ROS production 23.5 Æ 4.5% vs. 21.6 Æ 2.2%; both respectively), and the activity of nuclear factor-kappa B (NF-kB) and activator protein-1 (AP-1), but not specificity protein 1 (Sp1) was significantly higher in Group III than in Group II (2.53-fold vs. 2.0-fold vs. 1.43-fold, respectively). Both PBMC- and urinary TGF-b1 levels were higher in Group III than Group II (3.23 Æ 0.39 ng/g vs. 1.99 Æ 0.68 ng/g in PBMCs, 16.88 Æ 6.84 (ng/g Cr) vs. 5.61 Æ 1.57 (ng/g Cr) in urine, both respectively), and they correlated with the activity of NF-kB and AP-1 and 24-h urine albumin excretion (UAE). Increased intracellular ROS generation in PBMCs of diabetic patients is involved in the pathogenesis of diabetic nephropathy via activation NF-kB and AP-1 and an increased expression of TGF-b1. # 2008 Elsevier Ireland Ltd. All rights reserved. § This work was supported by a faculty research grant of Department of Internal Medicine, Yonsei University, College of Medicine and by Korean Diabetes Association for 2000. * Corresponding author at: Division of Endocrinology, Department for Internal Medicine, Yonsei University, College of Medicine, Kangnamku, 146-92 Dogokodng, 135-270 Seoul, Republic of Korea. Tel.: +82 2 2019 3339; fax: +82 2 3463 3882. E-mail address: acw@yuhs.ac (C.W. Ahn). 1 These authors contributed equally to this work. available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/diabres 0168-8227/$ – see front matter # 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.diabres.2008.01.032