MESENCHYMAL STEM CELLS IN THE PREVENTION OF THROMBOSIS AND NEOINTIMAL HYPERPLASIA

描述（由申请人提供）：药物洗脱支架导致较少的内膜增生和较少的晚期管腔损失，但抑制支架段的再内皮化，使其更容易形成血栓。因此，需要更长时间抗血小板治疗的再狭窄和晚期支架血栓形成之间存在权衡。显然，一种更好的治疗方法可以防止内膜增生和诱导再内皮化，这将有助于提供长期无症状的冠状动脉疾病控制，而不需要长期的抗血小板治疗。由于PTEN调节细胞信号传导和细胞生长，PTEN在动脉平滑肌细胞中的转基因过表达可阻止新生内膜增生的发生。此外，血栓形成可以通过内皮细胞分化的间充质干细胞（MSCs）修复内皮细胞来预防。我们假设将MSCs和PTEN转基因局部递送到血管成形术和支架损伤部位可以防止血栓形成和新生内膜增生的发展。MSCs中Wnt/2 catenin信号的下调促进内皮细胞分化和再内皮化。我们的数据表明，血管内皮生长因子（VGEF）引发的MSCs分化为内皮细胞，PTEN过表达抑制动脉平滑肌细胞的增殖，这一假设得到了支持。我们将在实验室中建立和常规使用的高脂血症和动脉粥样硬化猪模型中进行这些研究，血管成形术和支架内再狭窄。目的1：验证MSCs在冠状动脉粥样硬化球囊成形术部位过表达PTEN基因可以预防血栓形成和新生内膜增生的假设。目的2：验证在动脉粥样硬化的冠状动脉裸金属支架部位MSCs过表达PTEN转基因基因可以预防血栓形成和支架内再狭窄的假设，这将优于单独使用药物洗脱支架的效果。目的3：验证Wnt/2-catenin信号下调促进冠状动脉损伤部位MSC向内皮细胞分化的假设。我们将研究Wnt/ -catenin信号分子的作用，特别是-catenin， LRP5和Kremen1，作为体外和体内猪冠状动脉中MSCs分化为ECs和再内皮化的潜在机制。这些研究将使我们能够将我们的研究转化为临床一期研究，使用pten工程的自体间充质干细胞治疗冠状动脉介入手术引起的并发症，PTCA与pten工程的自体间充质干细胞可能消除冠状动脉疾病对支架的需求。

DESCRIPTION (provided by applicant): Drug-eluting stents cause less intimal hyperplasia and less late luminal loss, but inhibit re- endothelialization of the stented segment making it more susceptible to thrombosis. Thus, there is trade-off between restenosis and late stent thrombosis requiring longer periods of anti-platelet therapy. Clearly, a better therapeutic approach that can prevent intimal hyperplasia and induce re-endothelialization would be useful to provide long-term symptom-free control of coronary artery disease without the need for prolonged anti- platelet therapy. Since PTEN modulates cell signaling and cell growth, PTEN transgene overexpression in arterial smooth muscle cells would prevent the development of neointimal hyperplasia. In addition, thrombosis could be prevented by the repair of endothelial cells with mesenchymal stem cells (MSCs) which have been primed to differentiate into endothelial cells. We hypothesize that the delivery of MSCs and PTEN transgene locally to the site of angioplasty and stent injury prevents thrombosis and the development of neointimal hyperplasia. Down-regulation of Wnt/2 catenin signaling in MSCs promotes endothelial cell differentiation and re-endothelialization. This hypothesis has been supported by our data demonstrating that vascular endothelial growth factor (VGEF)-primed MSCs differentiate into endothelial cells and PTEN overexpression inhibits proliferation of arterial smooth muscle cells. We will do these studies in a well-established and routinely used in our laboratory the swine model of hyperlipidemia and atherosclerosis with angioplasty and in-stent restenosis. Aim 1: Test the hypothesis that overexpression of PTEN transgene with MSCs at the site of balloon angioplasty in atherosclerotic coronary artery prevents thrombosis and the development of neointimal hyperplasia. Aim 2: Test the hypothesis that overexpression of PTEN transgene with MSCs at the site of bare metal stenting in atherosclerotic coronary artery prevents thrombosis and in-stent restenosis and this would be superior to the effect of drug-eluting stent alone. Aim 3: Test the hypothesis that down-regulation of Wnt/2-catenin signaling promotes MSC differentiation to endothelial cells at the injury site in coronary arteries. We will examine the role of Wnt/¿-catenin signaling molecules, particularly ¿-catenin, LRP5 and Kremen1, as the underlying mechanism of MSCs differentiation into ECs and re-endothelialization both in vitro and in vivo in swine coronary arteries. These studies would position us to translate our investigation into a clinical phase 1 study for the use of PTEN-engineered autologous MSCs for the treatment of the complications due to coronary interventional procedures, and PTCA with PTEN-engineered autologous MSCs might eliminate the need of stents in coronary artery disease.