MESENCHYMAL STEM CELLS IN THE PREVENTION OF THROMBOSIS AND NEOINTIMAL HYPERPLASIA

描述（由申请人提供）：药物洗脱支架引起的内膜增生和晚期管腔丢失较少，但抑制了支架段的再内皮化，使其更容易发生血栓形成。因此，在再狭窄和晚期支架血栓形成之间存在权衡，需要更长时间的抗血小板治疗。显然，可以预防内膜增生并诱导再内皮化的更好的治疗方法将有助于提供冠状动脉疾病的长期无血栓控制，而不需要延长的抗血小板治疗。由于PTEN调节细胞信号传导和细胞生长，因此在动脉平滑肌细胞中PTEN转基因过表达将防止新生内膜增生的发展。此外，可以通过用间充质干细胞（MSC）修复内皮细胞来防止血栓形成，所述间充质干细胞已被诱导分化为内皮细胞。我们假设，间充质干细胞和PTEN转基因局部血管成形术和支架损伤的网站，防止血栓形成和发展的新生内膜增生。下调Wnt/2 catenin信号通路促进内皮细胞分化和再内皮化这一假设得到了我们的数据的支持，我们的数据表明，血管内皮生长因子（VGEF）引发的MSC分化为内皮细胞和PTEN过表达抑制动脉平滑肌细胞的增殖。我们将在我们实验室中建立并常规使用的高脂血症和动脉粥样硬化的猪模型中进行这些研究，包括血管成形术和支架内再狭窄。目标1：验证在动脉粥样硬化冠状动脉球囊成形术部位用MSC过表达PTEN转基因可预防血栓形成和新生内膜增生的发展的假设。目标二：验证在动脉粥样硬化冠状动脉裸金属支架植入部位用MSC过表达PTEN转基因预防血栓形成和支架内再狭窄的假设，这将上级单独的药物洗脱支架的效果。目标3：检验Wnt/2-catenin信号转导下调促进冠状动脉损伤部位MSC分化为内皮细胞的假设。我们将研究Wnt/<$-连环蛋白信号分子，特别是<$-连环蛋白，LRP 5和Kremen 1的作用，作为MSC分化为EC和再内皮化的潜在机制，在体外和体内猪冠状动脉。这些研究将使我们能够将我们的研究转化为临床1期研究，使用PTEN工程化自体MSC治疗冠状动脉介入手术引起的并发症，并且使用PTEN工程化自体MSC的PTCA可能消除冠状动脉疾病中支架的需要。

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.