Department of Nephrology and Rheumatology, University Hospital of Göttingen, Göttingen, Germany.
J Nephrol. 2013 Jul-Aug;26(4):667-74. doi: 10.5301/jn.5000255. Epub 2013 Mar 6.
Early endothelial outgrowth cells (eEOCs) significantly protect mice from acute kidney injury (AKI). Angiopoietin-2 (Ang-2) has been shown to be critically involved in vascular repair and homeostasis. The aim of this study was to investigate consequences of Ang-2 treatment of syngeneic murine eEOCs in a cell-based therapeutic approach for AKI.
Male 8- to 12-week-old C57/Bl6N mice, subjected to unilateral renal ischemia (40 minutes) postuninephrectomy were systemically injected with 0.5 × 10(6) untreated or Ang-2-pretreated syngeneic murine eEOCs. Renal function and morphology were analyzed 48 hours later. Cellular consequences of eEOC treatment with Ang-2 were evaluated using different in vitro assays (direct and indirect migration, apoptosis/necrosis, ELISA studies).
Administration of untreated eEOCs did not protect mice from AKI. Ang-2 dose-dependently modulated cell effects in AKI. While incubating the cells at a concentration of 200 ng/mL (1 hour) did not have any effect on renal function, doubling the concentration (400 ng/mL) resulted in significant renoprotection of cell-injected mice. With 800 ng/mL, cell injection dramatically worsened renal function of treated animals. In vitro analysis showed significantly accelerated migration of cultured mature endothelial cells after incubation with supernatant from Ang-2-treated eEOCs (200 and 400 ng/mL). These effects were most pronounced with 400 mg/mL. In addition, Ang-2 promoted survival of eEOCs. Cellular releases of VEGF and IL-6 were decreased by Ang-2, while TGF-β levels in the medium of Ang-2-stimulated eEOCs were not different from those in untreated cells.
Ang-2 acts as modulator of eEOCs in AKI. The migration analysis indicates that the Ang-2 significantly alters indirect (paracrine) activity of eEOCs, thus promoting renoprotection in a dose-dependent manner.
早期内皮细胞外生长细胞（eEOC）可显著保护小鼠免受急性肾损伤（AKI）。血管生成素-2（Ang-2）已被证明在血管修复和稳态中起关键作用。本研究旨在研究 Ang-2 处理同种异体鼠 eEOC 在 AKI 细胞治疗方法中的作用。
雄性 8-12 周龄 C57/Bl6N 小鼠，在单侧肾缺血（40 分钟）后进行单侧肾切除术，系统注射 0.5×10（6）未经处理或 Ang-2 预处理的同种异体鼠 eEOC。48 小时后分析肾功能和形态。使用不同的体外测定法（直接和间接迁移、凋亡/坏死、ELISA 研究）评估 eEOC 用 Ang-2 处理的细胞后果。
给予未经处理的 eEOC 不能保护小鼠免受 AKI。Ang-2 以剂量依赖的方式调节 AKI 中的细胞效应。虽然将细胞孵育在 200ng/ml（1 小时）的浓度下对肾功能没有任何影响，但将浓度提高一倍（400ng/ml）会显著保护注射细胞的小鼠的肾脏。使用 800ng/ml，细胞注射会使治疗动物的肾功能急剧恶化。体外分析表明，在用 Ang-2 处理的 eEOC 的上清液孵育后，培养成熟的内皮细胞的迁移明显加快（200 和 400ng/ml）。在 400ng/ml 时，这些效果最为明显。此外，Ang-2 促进了 eEOC 的存活。细胞释放的 VEGF 和 IL-6 被 Ang-2 降低，而 Ang-2 刺激的 eEOC 培养基中的 TGF-β水平与未处理的细胞没有不同。
Ang-2 是 AKI 中 eEOC 的调节剂。迁移分析表明，Ang-2 显著改变了 eEOC 的间接（旁分泌）活性，从而以剂量依赖的方式促进了肾脏保护。
