Mechanical Conditioning of Mesenchymal Stem Cells for Enhanced Recellularized Vascular Grafts

心血管疾病是世界范围内最常见的死亡原因，对社会和 美国医疗保健系统的财政负担。慢性阻塞性脉管病的形成 冠状动脉和外周血管通常需要进行搭桥手术，以便为血流提供管道。 绕过障碍物。虽然这种手术可以为患者提供恢复血流，但只有有限的 患者体内可供这些手术使用的自体动脉或静脉的数量。经常 这些血管也有血管疾病的存在，在许多情况下，由于 再狭窄加速闭塞。小直径的人造血管移植物已经被证明是非常 由于血栓形成和移植物失败而具有挑战性的发展。解决这个问题的一个有希望的方法是使用 组织工程血管移植物创造用于搭桥手术的新管道。脱细胞 动脉是一种非常吸引人的方法来创建组织工程支架，这种支架具有机械 性质类似于天然血管，不具有免疫原性，可以与从 有耐心的。机械力是血管动态平衡的重要组成部分，并提供必要的刺激 维持血管功能。此外，机械微环境是调节生物多样性的关键。 胚胎发育和损伤期间血管系统的重塑。在这里，我们将使用 机械力与生化信号和药物抑制剂相结合，以优化 骨髓间充质细胞诱导血管平滑肌细胞和内皮细胞的分化 干细胞(MSCs)。骨髓间充质干细胞很容易从患者身上获得，因此非常 呼吁提供自体细胞来源。这些机械条件下的间充质干细胞将被植入 通过使动脉脱细胞而形成的组织工程移植物。我们的主要目标是确定最佳条件 将MSCs分化为vSMC和内皮细胞表型，并检测机械条件下 在再细胞化的血管移植中，MSCs优于非条件MSCs。我们将着手解决这一问题 目的通过以下具体目标：(1)利用高通量、组合实验寻找 骨髓强大分化的生物化学、药理和力学协同条件 间充质干细胞转化为内皮细胞。(2)广泛评估机械拉伸的协同作用 生化刺激诱导骨髓间充质干细胞分化为血管平滑肌细胞(VSMCs)。 (3)检测机械条件下骨髓间充质干细胞的功能和长期分化能力 用于搭桥手术的再细胞化移植物。综上所述，这些研究将为机械地 介导干细胞生物学并为提高小直径再细胞化提供优化条件 血管移植。

Cardiovascular diseases are the most common cause of death worldwide and exert a massive social and financial burden on the healthcare system of the United States. The formation of occlusive vascular disease in the coronary and peripheral vascular often necessitates bypass graft surgery to provide a conduit for flow around the blockages. While this surgery can provide restoration of flow for the patient, there is only a limited amount of autologous arteries or veins in the patients that can be harvested for use in these surgeries. Often these vessels also have the presence of vascular disease and in many cases fail relatively rapidly due to accelerated occlusion by restenosis. Small diameter synthetic vascular grafts have proven extremely challenging to develop due to thrombosis and graft failure. A promising approach to this problem is to use tissue engineered vascular grafts to create new conduits to be used in bypass surgeries. Decellularized arteries are a very appealing approach for creating tissue engineered scaffolds that have mechanical properties similar to native vessels, are not immunogenic and can be seeded with cells harvested from the patient. Mechanical forces are an essential part of vascular homeostasis and provide needed stimuli to maintain blood vessel function. In addition, the mechanical microenvironment is key in regulating the remodeling of the vascular system during embryological development and during injury. Here, we will use mechanical forces in combination with biochemical signals and pharmacological inhibitors to optimize the generation of vascular smooth muscle cells (vSMCs) and endothelial cells from bone marrow mesenchymal stem cells (MSCs). Bone marrow MSCs are easily obtainable from patients and consequently are very appealing for providing autologous source of cells. These mechanically conditioned MSCs will be seeded into tissue engineered grafts created by decellularizing arteries. Our major goals are to identify optimal conditions to differentiate MSCs into vSMC and endothelial cell phenotype, and test whether mechanically conditioned MSCs are superior to non-conditioned MSCs when used in recellularized vascular grafts. We will approach this objective through the following specific aims: (1) Use high throughput, combinatorial experiments to find synergistic biochemical, pharmacological and mechanical conditions for robust differentiation of bone marrow MSCs into endothelial cells. (2) Perform an extensive evaluation of the synergistic role of mechanical stretch and biochemical stimulation in differentiating bone marrow MSCs into vascular smooth muscle cells (vSMCs). (3) Test the functionality and long-term differentiation of mechanically conditioned MSCs in enhancing recellularized grafts for bypass surgeries. Together these studies will provide new insights into mechanically mediated stem cell biology and provide optimized conditions for enhancing small diameter recellularized vascular grafts.