Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal Potsdam, Germany.
Biochem Biophys Res Commun. 2010 Feb 26;393(1):79-83. doi: 10.1016/j.bbrc.2010.01.082. Epub 2010 Jan 25.
Retinol-binding protein 4 (RBP4) is elevated in patients with chronic kidney disease (CKD) and has been discussed as marker of kidney function. In addition to an elevated concentration, the existence of truncated RBP4 species, RBP4-L (truncated at last C-terminal leucine) and RBP4-LL (truncated at both C-terminal leucines), has been reported in serum of hemodialysis patients. Since little is known about the occurrence of RBP4 species during the progression of CKD it was the aim of this study to analyse this possible association. The presence of RBP4, RBP4-L, RBP4-LL and transthyretin (TTR) was assessed in serum of 45 healthy controls and 52 patients with stage 2-5 of CKD using ELISA and RBP4 immunoprecipitation with subsequent MALDI-TOF-MS analysis. A reduction of glomerular filtration rate was accompanied by a gradual elevation of RBP4 serum levels and relative amounts of RBP4-LL. Correlation analysis revealed a strong association of the RBP4-TTR ratio with parameters of lipid metabolism and with diabetes-related factors. In conclusion, RBP4 serum concentration and the appearance of RBP4-LL seem to be influenced by kidney function. Furthermore, the RBP4-TTR ratio may provide diagnostic potential with regard to metabolic complications in CKD patients.
视黄醇结合蛋白 4（RBP4）在慢性肾脏病（CKD）患者中升高，并被讨论为肾功能标志物。除了浓度升高外，在血液透析患者的血清中还存在截短的 RBP4 物种，即 RBP4-L（最后一个 C 末端亮氨酸截断）和 RBP4-LL（两个 C 末端亮氨酸均截断）。由于人们对 CKD 进展过程中 RBP4 物种的发生知之甚少，因此本研究旨在分析这种可能的关联。使用 ELISA 和随后的 MALDI-TOF-MS 分析，对 45 名健康对照者和 52 名 CKD 2-5 期患者的血清中的 RBP4、RBP4-L、RBP4-LL 和转甲状腺素蛋白（TTR）进行了评估。肾小球滤过率降低伴随着 RBP4 血清水平和 RBP4-LL 的相对量逐渐升高。相关性分析显示，RBP4-TTR 比值与脂质代谢参数和与糖尿病相关的因素密切相关。总之，RBP4 血清浓度和 RBP4-LL 的出现似乎受肾功能的影响。此外，RBP4-TTR 比值可能为 CKD 患者的代谢并发症提供诊断潜力。
