The Restorative Effects of Niacin on Damaged Endothelial Progenitor Cells Induced by Indoxyl Sulfate

• Main Authors: Yu-Chin Huang, 黃鈺琴
• Other Authors: 吳寬墩
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/23124718515275970933

碩士 === 國立臺灣大學 === 臨床醫學研究所 === 101 === 【Background and Objective】 Substantial evidence has confirmed that endothelial dysfunction starts in the early stage of CKD,not only increasing damage to endothelial cell but affect of endothelial progenitor cells (EPCs) in the repair system.The uremic toxins−indoxyl sulfate (IS) exhibit renal and vascular toxicity, impaired endothelial cell proliferation and repair capacity. Nicotinic acid (Niacin) is the earliest lipid –lowering drug and has antioxidant capacity might helpful to prevent endothelial cell injury and restore the function of repair system. In this study, we focus on the adverse impact of IS on EPCs and to investigate if Niacin can antagonize the deleterious effect of IS to reduce the occurrence or deterioration of endothelial dysfunction. 【Material and Method】 In vitro study, mononuclear cells were isolated from peripheral blood from healthy donators and plated on culture dishes coated with fibronectin,adherent cells were differentiation to EPCs then confirmation was determined.EPCs were incubated with an additional IS to investigate the changes including apoptosis、senescence、autophage. EPCs function was tested by migration and tube formation ability.The restorative effects and mechanism of Niacin on damaged EPCs were survey. Study groups:were divided to three categories:control group, IS along group, and IS combined Niacin group. 【Result】 The effect on proliferation induced by .IS was in dose and time-dependent manner.IS at concentrations of 1mM induced a decreased proliferation in EPCs of 28% (p = 0.024) but was blunted by adding Niacin that the best effective dose is 1mM (p=0.0495).The presence of apoptosis biomarker-activated caspase-3 did not change after 1mM IS infusion but the autophagy marker LC3b expression were increased 80% and the percentage of senescence EPCs increases 100% (P<0.05).However, 1mM Niacin administration attenuated the IS-induced senescence reduced by 54% and decreased LC3b expression by 70%. Cumulative population doublings assay results showed that 1mM IS reduced the cell number about 61% (p=0.0097) but increased approximately 46%−96%. by 1mM Niacin (p =0.007).EPCs transwell migration ability decreased 45% (p <0.001) and tube formation capacity reduced by 49% (p = 0.0042) when 1mM IS was added. 1mM Niacin administration improved the transwell migration ability of 40% (p = 0.021),but tube formation capacity was not significant recovery (p = 0.416).Analysis of protein altered by IS(1mM),the HO-1 increased to 89 times attenuated approximately 50% by 1mM Niacin treatment.IS (1mM) increases the expression of p-AKT to 3.26 times, addition of 1mM Niacin had no effect on AKT, p-AKT expression. eNOS and VEGF expression were decreased by 77% (p <0.05) and 70% (p <0.05) respectively by IS (1mM) stimulation but 1mM Niacin treatment can enhance eNOS and VEGF expression with an increase of 130% ( p = 0.0016 ) and increase of 140%(p = 0.00030 ) respectively. IS (1mM) prompted ROS generation was blunted by 1 mM Niacin treatment. Niacin exclusive receptors GPR109A was not exist on EPCs. 【Conclusion】 Our study showed after Niacin treated,the impairment of EPCs proliferative capacity and function ability induced by the deleterious effect of IS is repaired. A antagonist mechanism of Niacin on damaged EPCs induced by IS may derive from the decrease of cell aging and autophagy,the elevation of the eNOs and VEGF expression, the decrease of the generation of free radicals .In the future,we hope to apply Niacin in clinical practice to improve endothelial function in patients with CKD.