IL-6 trans-signaling调控腹膜血管新生和通透性增高的机制研究

High peritoneal permeability develops with the duration of peritoneal dialysis (PD), leading to deterioration of peritoneal function and ultimately, peritoneal membrane failure, which accounts for the major cause of dropout of long-term PD therapy. However, the mechanisms of increased peritoneal permeability remain unclear. The present study: 1. Stable PD patients are enrolled and prospectively followed up to investigate the key contributors of peritoneal inflammation and the predictive value of inflammation for development of high peritoneal permeability; 2. Coculture system of human mesothelial cells (HPMCs) and endothelial cells is established in vitro. The role of IL-6 trans-signaling in promoting angiogenesis, Angpt/Tie2 expression, tight junction proteins distribution as well as the intrcellular signal pathways are determined; 3. Uremic PD animal model is constructed to study the role of IL-6 trans-signaling in distablized angiogenesis, expression of Angpt/Tie2, vascular leakness and peritoneal permeability. Effects of interfering IL-6 trans-signaling and Angpt/Tie2 are investigated by intraperitoneal administering sgp130Fc, which is a specific inhibitor of IL-6 trans-signaling, and the adenovirus vector containing COMP-Angpt1. This study explores the potential role of IL-6 trans-signaling in promoting peritoneal angiogenesis and high permeability, and might provide a new target for prevention and therapeutic strategies.

腹膜通透性增高是导致腹透患者不良预后的重要原因，而腹腔炎症是引起腹膜通透性增高的主要因素，但其确切机制仍不明了。本研究拟开展前瞻性研究随访腹透患者的腹膜通透性，研究腹腔局部炎症和系统炎症对腹膜通透性增高的远期作用；观察腹透液非生理性因素和尿毒症血清对人腹膜间皮细胞IL-6表达分泌的影响，建立人腹膜间皮细胞和内皮细胞共培养体系，探讨IL-6 trans-signaling对细胞血管新生能力、Angpt/Tie2表达、内皮紧密连接蛋白再分布的影响及其胞内信号传导通路；利用尿毒症腹透动物模型探讨IL-6 trans-signaling对Angpt/Tie2、腹膜血管密度、不稳定血管比例、微血管渗漏性及腹膜通透性的影响，并进一步研究阻断IL-6 trans-signaling对腹膜形态和功能的影响，以期阐述腹膜通透性增高的分子调控机制，为今后腹透患者防治腹膜功能衰竭提供新的理论依据。

腹膜通透性增高是导致腹透患者预后不良的重要原因。本研究从炎症角度探讨了长期腹透患者腹膜通透性增高的机制：1.入选稳定的腹膜透析患者，研究腹腔局部炎症和系统性炎症对腹膜通透性增高的作用；2.观察腹透液非生理性因素对腹膜间皮细胞IL-6表达分泌的影响，建立腹膜间皮细胞和内皮细胞共培养体系，探讨IL-6 trans-signaling对细胞血管新生能力、Angpt/Tie2表达、内皮紧密连接蛋白再分布的影响及其胞内信号传导通路；3.利用尿毒症腹透动物模型探讨IL-6 trans-signaling对腹膜血管密度、腹膜纤维化、炎症细胞浸润的影响。本研究入选稳定腹透患者320例，结果显示，BSA、历史葡萄糖暴露量、透析液IL-6AR和透析液Ang-1AR是影响腹膜小分子溶质转运率MTACcr的独立相关因素，而BSA和血清Ang-1是影响腹膜白蛋白转运功能的独立相关因素。高浓度葡萄糖和高渗透压可以促进腹膜间皮细胞合成和分泌IL-6；腹膜间皮细胞和内皮细胞共培养体系中，IL-6 trans-signaling可以下调Angpt-1的表达，上调Angpt-2和VEGF的表达，并下调血管内皮细胞间紧密连接蛋白VE-cadherin，occludin和claudin-5的表达IL-6 trans-signaling激活后腹膜间皮细胞中磷酸化STAT3的水平显著增高。动物模型中同样表明IL-6 trans-signaling通路介导不稳定血管新生，腹膜纤维化，炎症细胞浸润等多种病理过程，特异性抑制IL-6 trans-signaling通路可以显著降低高糖腹透液诱导的小鼠腹膜磷酸化STAT3蛋白的表达。上述结果提示非生物相容性腹透液可以导致腹腔IL-6分泌的增加，IL-6可通过IL-6 trans-signaling通路介导不稳定血管新生，腹膜纤维化，炎症细胞浸润等多种病理过程，STAT3参与了IL-6 trans-signaling通路的胞内信号转导过程。提示IL-6 trans-signaling信号通路可能是防治腹膜通透性增高的新靶点。