Remote ischemic preconditioning (RIPC) protects the heart against myocardial ischemia/reperfusion (I/R) injury and recent work also suggested chronic remote ischemic conditioning (cRIPC) for cardiovascular protection. Based on current knowledge that systemic immunomodulatory effects of RIPC and the anti-inflammatory capacity of monocytes might be involved in cardiovascular protection, the aim of our study was to evaluate whether RIPC/cRIPC blood plasma is able to induce in-vitro angiogenesis, identify responsible factors and evaluate the effects of RIPC/cRIPC on cell surface characteristics of circulating monocytes. Eleven healthy volunteers were subjected to RIPC/cRIPC using a blood pressure cuff inflated to > 200 mmHg for 3 × 5 min on the upper arm. Plasma and peripheral blood monocytes were isolated before RIPC (Control), after 1 × RIPC (RIPC) and at the end of 1 week of daily RIPC (cRIPC) treatment. Plasma concentrations of potentially pro-angiogenic humoral factors (CXCL5, Growth hormone, IGFBP3, IL-1α, IL-6, Angiopoietin 2, VEGF, PECAM-1, sTie-2, IL-8, MCSF) were measured using custom made multiplex ELISA systems. Tube formation assays for evaluation of in-vitro angiogenesis were performed with donor plasma, monocyte conditioned culture media as well as IL-1α, CXCL5 and Growth hormone. The presence of CD14, CD16, Tie-2 and CCR2 was analyzed on monocytes by flow cytometry. Employing in-vitro tube formation assays, several parameters of angiogenesis were significantly increased by cRIPC plasma (number of nodes, P < 0.05; number of master junctions, P < 0.05; number of segments, P < 0.05) but were not influenced by culture medium from RIPC/cRIPC treated monocytes. While RIPC/cRIPC treatment did not lead to significant changes of the median plasma concentrations of any of the selected potentially pro-angiogenic humoral factors, in-depth analysis of the individual subjects revealed differences in plasma levels of IL-1α, CXCL5 and Growth hormone after RIPC/cRIPC treatment in some of the volunteers. Nevertheless, the positive effects of RIPC/cRIPC plasma on in-vitro angiogenesis could not be mimicked by the addition of the respective humoral factors alone or in combination. While monocyte conditioned culture media did not affect in-vitro tube formation, flow cytometry analyses of circulating monocytes revealed a significant increase in the number of Tie-2 positive and a decrease of CCR2 positive monocytes after RIPC/cRIPC (Tie-2: cRIPC, P < 0.05; CCR2: RIPC P < 0.01). Cardiovascular protection may be mediated by RIPC and cRIPC via a regulation of plasma cytokines as well as changes in cell surface characteristics of monocytes (e.g. Tie-2). Our results suggest that a combination of humoral and cellular factors could be responsible for the RIPC/cRIPC mediated effects and that interindividual variations seem to play a considerable part in the RIPC/cRIPC associated mechanisms.

远程缺血预处理 (RIPC) 可保护心脏免受心肌缺血/再灌注 (I/R) 损伤，最近的工作还表明慢性远程缺血预处理 (cRIPC) 可用于心血管保护。基于目前对 RIPC 的全身免疫调节作用和单核细胞的抗炎能力可能参与心血管保护的认识，我们研究的目的是评估 RIPC/cRIPC 血浆是否能够诱导体外血管生成，确定负责任的因素并评估 RIPC/cRIPC 对循环单核细胞细胞表面特征的影响。11 名健康志愿者在上臂使用充气至 > 200 mmHg 的血压袖带进行 RIPC/cRIPC，持续时间为 3 × 5 分钟。在 RIPC（对照）之前分离血浆和外周血单核细胞，1 × RIPC (RIPC) 后和每日 RIPC (cRIPC) 治疗 1 周结束时。使用定制的多重检测潜在促血管生成体液因子（CXCL5、生长激素、IGFBP3、IL-1α、IL-6、血管生成素 2、VEGF、PECAM-1、sTie-2、IL-8、MCSF）的血浆浓度ELISA系统。用供体血浆、单核细胞条件培养基以及 IL-1α、CXCL5 和生长激素进行用于评估体外血管生成的管形成测定。通过流式细胞术在单核细胞上分析 CD14、CD16、Tie-2 和 CCR2 的存在。采用体外管形成测定，cRIPC 血浆显着增加了血管生成的几个参数（节点数，使用定制的多重 ELISA 系统测量 IGFBP3、IL-1α、IL-6、血管生成素 2、VEGF、PECAM-1、sTie-2、IL-8、MCSF)。用供体血浆、单核细胞条件培养基以及 IL-1α、CXCL5 和生长激素进行用于评估体外血管生成的管形成测定。通过流式细胞术在单核细胞上分析 CD14、CD16、Tie-2 和 CCR2 的存在。采用体外管形成测定，cRIPC 血浆显着增加了血管生成的几个参数（节点数，使用定制的多重 ELISA 系统测量 IGFBP3、IL-1α、IL-6、血管生成素 2、VEGF、PECAM-1、sTie-2、IL-8、MCSF)。用供体血浆、单核细胞条件培养基以及 IL-1α、CXCL5 和生长激素进行用于评估体外血管生成的管形成测定。通过流式细胞术在单核细胞上分析 CD14、CD16、Tie-2 和 CCR2 的存在。采用体外管形成测定，cRIPC 血浆显着增加了血管生成的几个参数（节点数，通过流式细胞术在单核细胞上分析 CD16、Tie-2 和 CCR2。采用体外管形成测定，cRIPC 血浆显着增加了血管生成的几个参数（节点数，通过流式细胞术在单核细胞上分析 CD16、Tie-2 和 CCR2。采用体外管形成测定，cRIPC 血浆显着增加了血管生成的几个参数（节点数，P  < 0.05；主节点数，P  < 0.05；段数，P < 0.05)，但不受来自 RIPC/cRIPC 处理的单核细胞的培养基的影响。虽然 RIPC/cRIPC 治疗不会导致任何选定的潜在促血管生成体液因子的中位血浆浓度发生显着变化，但对个体受试者的深入分析揭示了血浆 IL-1α、CXCL5 和生长激素水平的差异部分志愿者接受 RIPC/cRIPC 治疗后。然而，RIPC/cRIPC 血浆对体外血管生成的积极作用不能通过单独或组合添加相应的体液因子来模拟。虽然单核细胞条件培养基不影响体外试管的形成，P  < 0.05；CCR2：RIPC P  < 0.01）。心血管保护可能由 RIPC 和 cRIPC 通过调节血浆细胞因子以及改变单核细胞的细胞表面特性（例如 Tie-2）来介导。我们的研究结果表明，体液和细胞因子的组合可能是 RIPC/cRIPC 介导的作用的原因，并且个体间的差异似乎在 RIPC/cRIPC 相关机制中发挥了相当大的作用。