调控SDF-1α/CXCR4信号通道促进糖尿病外周动脉药物局部释放后内皮化的价值及机制研究

The less circulating endothelia progenitor cells (EPC) and their impaied function in diabetes had led delayed reendothelialization after local drug delivery, which resulted in late thrombosis and neointima hyperplasia. Recent studies indicated that impaired bone marrow(BM) EPC mobilization and homing was the key process for the delayed reendothelialization, and stromal cell derived factor-1α (SDF-1α)/CXCR4 signaling was important in response to tissue injury.We hypothesized that CXCR4 antagonist AMD3100 may restore EPC mobilization and SDF-1α may reverse the EPC homing in diabetes, which may accelerate reendothelialization after artery injury.In this study,the CXCR4 antagonist AMD3100 will be used to reverse BM EPC mobilization,then the phenotype, number and function (including adhesion, migration, differentiation) of EPC both in BM and blood from diabetic rats was evaluated before and after the treatment in vitro.After injection of AMD3100, either SDF-1α will be injected subcuteneously around the carotid artery or AMD3100 injected into spleen directly,the recruitment capacity of BM EPC in target vessel wall and the reendothelialization degree after carotid artery injury will be evaluated in vivo in diabetic animals. Furthermore, to investigate the effecacy of modification of the SDF-1α/CXCR4 axis in accelerating reendothelialization and reducing neointima formation after local drug delivery in diabetes,diabetic porcine peripheral artery will be treated with paclitaxel eluting balloon or stent with additional modifying the SDF-1α/CXCR4 axis, with bared balloon as control.

糖尿病导致了患者外周血的内皮祖细胞（EPC）数目减少、功能障碍，使得糖尿病下肢血管病介入治疗后再狭窄率居高不下。我们和其他的研究表明这与糖尿病患者骨髓EPC的动员和在血管损伤部位的归巢出现障碍所致的内皮化延迟有关。我们设想调控SDF-1α/CXCR4信号通路可促进EPC的动员、归巢而加速内皮化。本研究应用AMD3100促进EPC的动员、以SDF-1α促进EPC的归巢为手段，通过检测EPC动员前后糖尿病鼠骨髓和外周血EPC的数量、功能和归巢，动态观察糖尿病鼠外周动脉内膜损伤后内皮化时间、程度，确立调控SDF-1α/CXCR4信号通路促进糖尿病外周动脉损伤后内皮化的价值和最适方式；并在调控SDF-1α/CXCR4信号通道的基础上，对糖尿病猪髂动脉进行紫杉醇局部释放治疗，阐明调控此信号通道对促进靶血管药物局部释放后内皮化的影响和效果，为提高糖尿病外周动脉病变介入治疗后中长期通畅提供新思路。

研究背景：糖尿病导致了患者外周血的内皮祖细胞（EPC）数目减少、功能障碍，使得糖尿病下肢血管病介入治疗后再狭窄率居高不下。我们设想调控SDF-1α/CXCR4信号通路来促进EPC的动员、归巢而加速内皮化，从而降低再狭窄。.研究方法和结果：在大鼠的糖尿病模型上，通过观察细胞形态学特征及细胞增殖、黏附及迁移能力等的研究，我们发现糖尿病大鼠骨髓来源内皮祖细胞数量与正常大鼠相比无明显差异，但生物学活性降低，主要表现在增殖能力、黏附及迁移能力均减弱。应用AMD 3100虽可实现内皮祖细胞的动员，但将SDF-1在损伤局部或经尾静脉注射后，没有实现内皮祖细胞在大鼠损伤动脉局部的归巢，损伤的大鼠颈动脉内膜的修复没有显著的改善，而中膜的增生较显著，其原因尚在进一步的研究中。我们尝试从容易分离、培养及具有较强增殖能力的人类脐带血内皮祖细胞培养液提取中外泌体，结果发现这种外泌体能增强内皮细胞的功能，不仅能促进SD大鼠颈动脉损伤后内皮化，而且能促进糖尿病大鼠皮肤溃疡的修复。.在临床研究中我们发现，对于下肢动脉慢性闭塞病变，小腿加压MRA所显示的远端流出道，能够帮助调整治疗方案，提请术者更多地使用腔内技术而非内膜下成形术，并预示更好的治疗结果。和膝下顺行血管成形术相比，经足底弓逆行血管成形术可以取得更好的及时血流再通，相同的ABI改善、原发性血管通畅率及保肢率，在膝下顺行血管成形术失败后，它是有效的补充方法。.科学意义：人类脐带血内皮祖细胞来源的外泌体为降低糖尿病下肢血管病介入治疗后再狭窄率提供了一条新思路。使用小腿加压MR血管成像、经足底弓逆行血管成形术有助于提高介入手术成功率，保持靶血管的中、长期通畅。