Clinic for Nephrology and Critical Care Medicine, Charite-Universitatsmedizin Berlin, corporate member of Freie Universitat Berlin, Humboldt-Universitat zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany.
Berlin Institute of Health (BIH), Berlin, Germany.
Nephrol Dial Transplant. 2018 Apr 1;33(4):574-585. doi: 10.1093/ndt/gfx316.
Vascular calcification is enhanced in uraemic chronic haemodialysis patients, likely due to the accumulation of midsize uraemic toxins, such as interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Here we have assessed the impact of uraemia on vascular smooth muscle cell (VSMC) calcification and examined the role of IL-6 and TNF-α as possible mediators and, most importantly, its underlying signalling pathway in VSMCs.
VSMCs were incubated with samples of uraemic serum obtained from patients treated with haemodialysis for renal failure in the Permeability Enhancement to Reduce Chronic Inflammation-I clinical trial. The VSMCs were assessed for IL-6 gene regulation and promoter activation in response to uraemic serum and TNF-α with reporter assays and electrophoretic mobility shift assay and for osteoblastic transition, cellular calcification and cell viability upon osteogenic differentiation.
Uraemic serum contained higher levels of TNF-α and IL-6 compared with serum from healthy individuals. Exposure of VSMCs to uraemic serum or recombinant TNF-α lead to a strong upregulation of IL-6 mRNA expression and protein secretion, which was mediated by activator protein 1 (AP-1)/c-FOS-pathway signalling. Uraemic serum induced osteoblastic transition and calcification of VSMCs could be strongly attenuated by blocking TNF-α, IL-6 or AP-1/c-FOS signalling, which was accompanied by improved cell viability.
These results demonstrate that uraemic serum contains higher levels of uraemic toxins TNF-α and IL-6 and that uraemia promotes vascular calcification through a signalling pathway involving TNF-α, IL-6 and the AP-1/c-FOS cytokine-signalling axis. Thus treatment modalities aiming to reduce systemic TNF-α and IL-6 levels in chronic haemodialysis patients should be evaluated in future clinical trials.
尿毒症慢性血液透析患者的血管钙化增强，可能是由于中等大小尿毒症毒素的积累，如白细胞介素 6（IL-6）和肿瘤坏死因子-α（TNF-α）。在这里，我们评估了尿毒症对血管平滑肌细胞（VSMC）钙化的影响，并研究了 IL-6 和 TNF-α作为可能的介质的作用，以及最重要的是，其在 VSMC 中的潜在信号通路。
将尿毒症患者血液透析治疗的尿毒症血清样本与 VSMC 孵育。通过报告基因检测和电泳迁移率变动分析，评估尿毒症血清和 TNF-α对 VSMC 中 IL-6 基因调控和启动子激活的影响，并进行成骨分化后成骨样转化、细胞钙化和细胞活力的检测。
与健康个体的血清相比，尿毒症血清中含有更高水平的 TNF-α和 IL-6。VSMC 暴露于尿毒症血清或重组 TNF-α会导致 IL-6 mRNA 表达和蛋白分泌的强烈上调，这是由激活蛋白 1（AP-1）/c-FOS 通路信号介导的。尿毒症血清诱导 VSMC 成骨样转化和钙化，可以通过阻断 TNF-α、IL-6 或 AP-1/c-FOS 信号通路得到强烈抑制，同时细胞活力得到改善。
这些结果表明，尿毒症血清中含有更高水平的尿毒症毒素 TNF-α和 IL-6，尿毒症通过涉及 TNF-α、IL-6 和 AP-1/c-FOS 细胞因子信号轴的信号通路促进血管钙化。因此，旨在降低慢性血液透析患者全身 TNF-α和 IL-6 水平的治疗方法应在未来的临床试验中进行评估。
