下肢缺血时血管新生能力不足是研究中的难点，既往我们研究发现VEGF能够增强血管内皮祖细胞（EPCs）的血管新生能力，且能改善小鼠的下肢缺血，新近研究表明：经相关miRNA修饰的EPCs血管新生能力也明显增强，且miRNA可影响间充质干细胞的VEGF表达。故我们提出假说：某些miRNA通过影响VEGF及KDR的表达改变EPCs治疗下肢缺血时促血管新生的能力。我们拟提取下肢缺血患者与具有相同危险因素但未患病的对照者外周血中EPCs并对其行miRNA基因芯片分析，观察表达谱变化，筛选出相关VEGF及KDR表达的miRNA，将包含筛查出的特定miRNA及anti-miRNA的病毒转染到EPCs中，观察其对血管新生能力的影响，以及VEGF与KDR变化，从而验证相关的miRNA对VEGF及KDR表达的影响及对EPC促血管新生的能力的改变，期待为该疾病的诊治提供新的思路。

Angiogenesis deficiency in lower limb ischemia is a research difficulty. Our previous studies have found, VEGF significantly enhance the ability of EPCs angiogenesis and improve the situation of lower limb ischemia mouse model. Recent studies showed that the miRNA modified EPCs were significantly enhanced in capabilities of angiogenesis and miRNA can affect the expression of VEGF in mesenchymal.stem.cell. So we propose hypotheses: certain miRNA has the ability to change the angiogenesis of EPCs in treating hindlimb ischemia by affecting the expression of VEGF and KDR. We intend to collect peripheral blood EPCs of hindlimb ischemia patients and normal people with same risk factors, perform microarray analysis of their miRNA, observe changes in expression profiling, screening VEGF and KDR expression related miRNA. Transfected screeninged specific miRNA and anti-miRNA virus into EPCs, and then observe the effects on the ability to promote angiogenesis, and changes of VEGF and KDR, in order to verify the impact by the associated miRNA on the expression of VEGF and KDR and changes in the ability of the EPC angiogenesis. We expect to find a new way to diagnosis of ASO patients and to treat lower limb ischemia.