腺相关病毒介导SDF-1和VEGF165双基因修饰血管内皮祖细胞治疗脓毒症的实验研究

脓毒症/感染性休克是危重病患者多器官功能衰竭和死亡的主要原因。内皮细胞的损伤和激活在脓毒症的发生发展中具有重要的作用。我们前期研究发现：作为血管内皮细胞的前体，来源于骨髓的血管内皮祖细胞(EPCs)能促进缺血后的肢体和心肌新生血管形成，增加心肌局部收缩力，改善心功能。血管内皮生长因子（VEGF）能有效动员EPCs，增加其数目和功能。基质细胞衍生因子-1及其受体（SDF-1/CXCR4）能有效提高EPCs 数量，促进EPCs 黏附、增殖、诱导迁移和抑制凋亡来改善EPCs 的功能。本研究拟以腺相关病毒为载体，通过基因修饰技术将VEGF基因和SDF-1基因共转染入EPCs，移植入脓毒症小鼠体内，观察内皮细胞损伤修复情况和对脓毒症小鼠的保护作用及其机制。为脓毒症的治疗开辟新的途径，也为更好地应用成体干细胞移植治疗人类疾病提供新的思路。

Sepsis/septic shock is the main cause of death in critical ill patients with multiple organ failure. The damage and activation of endothelial cells play an important role in the development of sepsis and severe sepsis. Thus,understanding the mechanisms that maintain and restore endothelial function may have important clinical implications. Endothelial progenitor cells(EPCs) are critically involved in maintaining vascular homeostasis and in mediating macro- and microvascular repair under both physiological and pathological conditions. Our previous studies have indicated that bone marrow-derived endothelial progenitor cells,as vascular endothelium precursor cells,augmented neovascularization in ischemia hindlimb and myocardium,increased myocardial local contractility and improved cardiac function. Nevertheless,the number and the quality of bone marrow-derived endothelial progenitor cells is limited. Vascular endothelial growth factor (VEGF) has been identified as a key component in the development of blood vessels, but VEGF alone may be insufficient to achieve functional and mature development of the vasculature. Stromal-derived factor-1 (SDF-1) is the only known chemokine capable of migration of hematopoietic stemcells (HSCs), as the fluctuations in SDF-1 expression controlled the fluctuated steady-state of HSCs and their progenitors in peripheral blood . Among these, the SDF-1a and its receptor 4 (CXCR4) play a key role in mobilization and migration of EPCs. This study intends to use adeno-associated virus as vector and to transfect VEGF gene and SDF-1 gene into EPCs by use of the technique of gene modification.Subsequently,to transplant modified EPCs into the body of sepsis mice. The aim of this study is to observe the endothelium repair and angiogenesis and to investigate the protective effects and its molecular mechanisms of EPCs transplantation on sepsis mice.This study will provide a potential way for sepsis cell replacement therapy and a novel therapeutic idea for the application of mature stem cells transplanation in human diseases.