Division of Life and Pharmaceutical Sciences, Department of Bioinspired Science, College of Pharmacy, Ewha Womans University, Seoul, Korea.
Perit Dial Int. 2012 Jan-Feb;32(1):20-8. doi: 10.3747/pdi.2009.00228. Epub 2010 Aug 26.
Accumulation of visceral fat is one of the major risk factors for the development of cardiovascular disease in peritoneal dialysis (PD) patients. Adiponectin, an adipokine commonly regarded as a negative indicator of metabolic disease, is reported to be downregulated in its gene level in end-stage renal disease patients. Since excessive fat deposit is involved in increased reactive oxygen species (ROS), PD solution (PDS) may contribute to ROS production, resulting in dysregulation of adiponectin. In this study, we tested our hypothesis that oxidative stress induced by PDS may play a role in the regulation of adiponectin.
Commercial PDS containing 3.86% glucose (20 - 30 mL) was administered to SD rats for 12 weeks with and without N-acetylcysteine (NAC; 10 mmol/L). ELISA was used to quantify adiponectin in plasma and spent dialysate. For in vitro studies, fully differentiated 3T3-L1 adipocytes and adipocytes isolated from abdominal fat were treated with a high glucose solution, PDS, and H(2)O(2). Adiponectin levels in the conditioned media were measured by ELISA and immunoblot assays. The mRNA levels of adiponectin in mature adipocytes were examined using real-time RT-PCR.
The levels of adiponectin in plasma and spent dialysate were significantly downregulated by PDS and this effect was suppressed by NAC. In 3T3-L1 adipocytes, adiponectin secretion was inhibited by 50 mmol/L glucose, PDS diluted 2-fold, and H(2)O(2) (200 μmol/L). In addition, H(2)O(2) downregulated expression of adiponectin mRNA and secretion of adiponectin oligomer complexes.
Our data suggest that ROS induced by conventional glucose-based PDS may contribute to pathophysiological changes in abdominal fat and downregulate adiponectin secreted from adipocytes during long-term PD.
内脏脂肪堆积是腹膜透析（PD）患者发生心血管疾病的主要危险因素之一。脂联素是一种常见的代谢疾病负性标志物，有报道称其在终末期肾病患者中基因水平下调。由于过多的脂肪沉积涉及到活性氧（ROS）的增加，PD 液（PDS）可能会促进 ROS 的产生，导致脂联素的失调。在这项研究中，我们验证了我们的假设，即 PDS 诱导的氧化应激可能在调节脂联素方面发挥作用。
用含 3.86%葡萄糖（20-30 mL）的商业 PDS 对 SD 大鼠进行 12 周的处理，同时用或不用 N-乙酰半胱氨酸（NAC；10 mmol/L）。采用 ELISA 法检测血浆和废弃透析液中的脂联素。对于体外研究，用高葡萄糖溶液、PDS 和 H₂O₂处理完全分化的 3T3-L1 脂肪细胞和从腹部脂肪中分离的脂肪细胞。采用 ELISA 和免疫印迹法测定条件培养基中的脂联素水平。用实时 RT-PCR 法检测成熟脂肪细胞中脂联素的 mRNA 水平。
PDS 显著下调了血浆和废弃透析液中的脂联素水平，NAC 抑制了这一作用。在 3T3-L1 脂肪细胞中，50 mmol/L 葡萄糖、稀释 2 倍的 PDS 和 H₂O₂（200 μmol/L）均抑制了脂联素的分泌。此外，H₂O₂下调了脂联素 mRNA 的表达和单体复合物的分泌。
我们的数据表明，传统基于葡萄糖的 PDS 产生的 ROS 可能导致腹部脂肪的病理生理变化，并下调长期 PD 期间脂肪细胞分泌的脂联素。
