Development of Undifferentiated Embryonic Stem Cell- incorporated Small Caliber Vascular Prostheses

胚胎干细胞（ES细胞）有望成为自体细胞结合杂交人工器官的替代细胞资源。然而，关于胚胎干细胞在体内行为的信息很少。血管壁细胞在体内持续受到生物力学刺激，如流体动力绝对应力、周期性拉伸和脉动压力。因此，在考虑将胚胎干细胞应用于循环系统时，了解其在这种条件下的行为是非常重要的。为了研究胚胎干细胞在体内血流动力学条件下的行为，本研究建立了系统的胚胎干细胞掺入杂交血管假体的动物实验模型。将胎鼠胚胎干细胞随机分化于IV型胶原包被培养板上，诱导Flk-1+细胞。将细胞分选前后的细胞分别播种于直径为1.5mm的聚氨酯血管假体管腔表面。与VEGF孵育预定天数后，使用专门设计的连接装置将移植物植入裸鼠主动脉，最长可达7天。对移植物进行形态学和免疫学检查。植入后，植入的胚胎干细胞在搏动血流作用下保留在移植物表面。由于胚胎干细胞携带Lac-Z基因，因此可以确定观察到的细胞来自合并的胚胎干细胞。观察到的细胞呈多角形，尚未表现出本系列血管壁细胞的典型方面（=<7天）。然而，一些植入的ES细胞表现出PECAM-1，这表明在生物力学和生物化学刺激下，胚胎干细胞在体内进一步分化。该胚胎干细胞掺入杂交血管假体是研究胚胎干细胞在体内血流动力学条件下行为的首个模型，可能为胚胎干细胞掺入心血管人工器官的临床应用提供重要信息。少

Embryonic stem cells (ES cells) are expected as alternative cell resources for autologous cell-incorporated hybrid artificial organs. However, there have been very little information about ES cell behaviors in vivo. Vascular wall cells in vivo are continuously exposed to biomechanical stimulations, such as hydrodynamic sheer stress, periodical stretching and pulsatile pressure. Therefore it is very important to know the behaviors of ES cells under such conditions when application of the cells to circulatory systems is considered.To investigate the behavior of the ES cells under hemodynamic conditions in vivo, we developed the systematic animal experimental model of ES cell-incorporated hybrid vascular prostheses in this study.ES cells derived from a fetal mouse were randomly differentiated on the Type IV collagen-coated culture plates in vitro to induce Flk-1+ cells. Next, the cells before and after cell sorting were seeded on the luminal surface of polyurethane vascular prostheses wit … More h a diameter of 1.5mm. After incubation with VEGF for predetermined days, the grafts were implanted to the aortas of nude rats for up to 7 days with the use of specially designed connecting devices. Implanted grafts were examined morphologically and immunologically.After implantation, incorporated ES cells retained on the surface of the grafts under the exposure to pulsatile blood flow. Since ES cells were raveled with Lac-Z gene, it was possible to determine that the observed cells were derived from incorporated ES cells. Observed cells were polygonal shaped and did not yet exhibit the typical aspects of the vascular wall cells in this series (=<7 days). However, some of the incorporated ES cells, exhibited PECAM-1, which indicated that further in vivo differentiation of the ES cells was induced under bio-mechanical and bio-chemical stimulations.This ES cells-incorporated hybrid vascular prosthesis is the first model for investigation of the behavior of ES cells under hemodynamic conditions in vivo, and might provide important information for clinical application of ES cell-incorporated cardiovascular artificial organs. Less