硫酸盐对甲酚促糖化效应推进慢性肾功能不全时动脉粥样硬化发生及机制研究

The occurrence of atherosclerosis is high in patients with chronic kidney disease (CKD) and reason for this remains not fully understood. Our study suggests that this increment is related to p-cresol sulfate (pCS), a uremic toxin, which resist to dialysis. In this study, we show that pCS possess pro-glycation function. Advanced glycation end-products and the expression of receptor for advanced glycation end-products (RAGE) is increased in aortic tissue in mouse model of high pCS levels. In vitro, albumin is glycated after mixture with pCS for 6 months and the glycation degree is further elevated in condition of high-glucose level. Albumin of pCS modification induces expression of adhesion molecules and promotes adhesion of monocytoid cells to endothelium cells. Moreover, altered distribution of EV-cadherin and recruitment of stress fiber is observed in endothelial cells (EVC304) after culture with medium containing pCS for 2 month and in vitro angiogenesis is also impaired in the same cells. Furthermore, HDL displays attenuated lipid transportation after co-culture with pCS for 6 months. Collectively, these results suggest that long-term increase of pCS level solicit glycation in vivo, leading to endothelial impairment and mitigated anti-inflammatory effects and metabolic function, which lay down the basis for atherosclerosis. In the future study, we will confirm the atherogenic effects of pCS in mouse model with high pCS level and evaluate RAGE pathway mediation of pCS effects using RAGE-KO mouse. In addition, pCS effects will be assessed in detail in endothelium cell, macrophage and vascular smooth muscle cell, with mechanism clarification.

慢性肾功能不全（CKD）患者动脉粥样硬化发生率高，但原因未明。这与体内不易去除的尿毒症毒素硫酸盐对甲酚（pCS）有关。我们发现pCS对细胞毒性不强，但具有促糖化作用。高pCS水平小鼠模型的主动脉组织中终末糖化产物含量及其受体（RAGE）表达增高。白蛋白经pCS孵育6月后被糖化，合并高糖时糖化更甚。经pCS处理的白蛋白诱导内皮细胞表达粘附分子和促进巨噬细胞对内皮细胞体外粘附。内皮细胞经pCS处理2月后EV-cadherin分布和细胞骨架动员异常，体外成血管功能减退。HDL经pCS处理6月后脂质转运功能受损。提示pCS长期升高促进体内糖化机制，使内皮细胞受损且代谢抗炎功能异常，与CKD时动脉粥样硬化有关。后续将以体内实验明确高pCS水平致动脉粥样硬化作用，用RAGE-KO小鼠验证RAGE途径介导pCS致病，体外实验探讨pCS合并高低糖对内皮细胞、巨噬细胞和平滑肌细胞的作用，阐明pCS作用机制。

慢性肾功能不全（CKD）患者动脉粥样硬化发生率高，但原因未明。这与体内不易去除的尿毒症毒素硫酸盐对甲酚（PCS）有关。本课题通过多元Logistic回归显示，在行血液透析的患者中，血清PCS水平的升高是颈动脉粥样硬化斑块发生的独立危险因素，且PCS水平和颈动脉斑块的进展正相关，多元线性回归分析表明PCS水平的升高是颈动脉粥样斑块进展的独立预测因子。后续无论在蛋白水平还是mRNA水平均证实，PCS可刺激内皮细胞和巨噬细胞内炎症因子和细胞粘附因子的高表达，促进单核细胞向血管内皮的粘附，并且增加上述细胞内ROS的产生。而PCS的上述生物学效应均可被NADPH氧化酶抑制剂所抑制。动物实验证实PCS促进APOE-/-小鼠主动脉粥样斑块的发生，促进其血管组织中炎症水平的升高及ROS产生增加。而上述表现在一定程度上可被NADPH氧化酶抑制剂夹竹桃素所抑制。以上实验数据表明，尿毒症毒素PCS可通过促氧化应激作用，介导动脉粥样硬化的发生发展。