Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA.
Proc Natl Acad Sci U S A. 2011 May 31;108(22):9214-9. doi: 10.1073/pnas.1019506108. Epub 2011 May 12.
Arterial tissue-engineering techniques that have been reported previously typically involve long waiting times of several months while cells from the recipient are cultured to create the engineered vessel. In this study, we developed a different approach to arterial tissue engineering that can substantially reduce the waiting time for a graft. Tissue-engineered vessels (TEVs) were grown from banked porcine smooth muscle cells that were allogeneic to the intended recipient, using a biomimetic perfusion system. The engineered vessels were then decellularized, leaving behind the mechanically robust extracellular matrix of the graft wall. The acellular grafts were then seeded with cells that were derived from the intended recipient--either endothelial progenitor cells (EPC) or endothelial cell (EC)--on the graft lumen. TEV were then implanted as end-to-side grafts in the porcine carotid artery, which is a rigorous testbed due to its tendency for graft occlusion. The EPC- and EC-seeded TEV all remained patent for 30 d in this study, whereas the contralateral control vein grafts were patent in only 3/8 implants. Going along with the improved patency, the cell-seeded TEV demonstrated less neointimal hyperplasia and fewer proliferating cells than did the vein grafts. Proteins in the mammalian target of rapamycin signaling pathway tended to be decreased in TEV compared with vein grafts, implicating this pathway in the TEV's resistance to occlusion from intimal hyperplasia. These results indicate that a readily available, decellularized tissue-engineered vessel can be seeded with autologous endothelial progenitor cells to provide a biological vascular graft that resists both clotting and intimal hyperplasia. In addition, these results show that engineered connective tissues can be grown from banked cells, rendered acellular, and then used for tissue regeneration in vivo.
先前报道的动脉组织工程技术通常需要数月的长时间等待，在此期间，受体的细胞被培养以制造工程化的血管。在这项研究中，我们开发了一种不同的动脉组织工程方法，可以大大缩短移植物的等待时间。使用仿生灌注系统，从供体同种异体的银行保存的猪平滑肌细胞中生长组织工程血管 (TEV)。然后对工程化血管进行脱细胞处理，留下移植壁机械坚固的细胞外基质。然后将源自预期受体的细胞——内皮祖细胞 (EPC) 或内皮细胞 (EC)——接种到移植物管腔中的无细胞移植物上。然后将 TEV 作为端侧移植物植入猪颈动脉中，由于其移植物闭塞的倾向，这是一个严格的测试平台。在这项研究中，EPC 和 EC 接种的 TEV 在 30 天内均保持通畅，而对侧对照静脉移植物仅在 8 个植入物中有 3 个通畅。随着通畅性的提高，与静脉移植物相比，细胞接种的 TEV 显示出更少的新生内膜增生和更少的增殖细胞。与静脉移植物相比，雷帕霉素靶蛋白信号通路中的蛋白质在 TEV 中趋于减少，这表明该通路参与了 TEV 抵抗内膜增生引起的闭塞。这些结果表明，一种现成的、去细胞化的组织工程血管可以用自体内皮祖细胞接种，提供一种抵抗血栓形成和内膜增生的生物血管移植物。此外，这些结果表明，工程化的结缔组织可以从银行保存的细胞中生长，脱细胞，然后用于体内组织再生。
