Krawiec Jeffrey T, Liao Han-Tsung, Kwan LaiYee Lily, D'Amore Antonio, Weinbaum Justin S, Rubin J Peter, Wagner William R, Vorp David A
Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa.
Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pa; Division of Trauma Plastic Surgery, Department of Plastic and Reconstructive Surgery, Craniofacial Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
J Vasc Surg. 2017 Sep;66(3):883-890.e1. doi: 10.1016/j.jvs.2016.09.034. Epub 2016 Dec 22.
One of the rate-limiting barriers within the field of vascular tissue engineering is the lengthy fabrication time associated with expanding appropriate cell types in culture. One particularly attractive cell type for this purpose is the adipose-derived mesenchymal stem cell (AD-MSC), which is abundant and easily harvested from liposuction procedures. Even this cell type has its drawbacks, however, including the required culture period for expansion, which could pose risks of cellular transformation or contamination. Eliminating culture entirely would be ideal to avoid these concerns. In this study, we used the raw population of cells obtained after digestion of human liposuction aspirates, known as the stromal vascular fraction (SVF), as an abundant, culture-free cell source for tissue-engineered vascular grafts (TEVGs).
SVF cells and donor-paired cultured AD-MSCs were first assessed for their abilities to differentiate into vascular smooth muscle cells (SMCs) after angiotensin II stimulation and to secrete factors (eg, conditioned media) that promote SMC migration. Next, both cell types were incorporated into TEVG scaffolds, implanted as an aortic graft in a Lewis rat model, and assessed for their patency and composition.
In general, the human SVF cells were able to perform the same functions as AD-MSCs isolated from the same donor by culture expansion. Specifically, cells within the SVF performed two important functions; namely, they were able to differentiate into SMCs (SVF calponin expression: 16.4% ± 7.7% vs AD-MSC: 19.9%% ± 1.7%) and could secrete promigratory factors (SVF migration rate relative to control: 3.1 ± 0.3 vs AD-MSC: 2.5 ± 0.5). The SVF cells were also capable of being seeded within biodegradable, elastomeric, porous scaffolds that, when implanted in vivo for 8 weeks, generated patent TEVGs (SVF: 83% patency vs AD-MSC: 100% patency) populated with primary vascular components (eg, SMCs, endothelial cells, collagen, and elastin).
Human adipose tissue can be used as a culture-free cell source to create TEVGs, laying the groundwork for the rapid production of cell-seeded grafts.
血管组织工程领域的限速障碍之一是在培养中扩增合适细胞类型所需的漫长制备时间。用于此目的的一种特别有吸引力的细胞类型是脂肪来源的间充质干细胞（AD-MSC），它数量丰富且易于从抽脂手术中获取。然而，即使这种细胞类型也有其缺点，包括扩增所需的培养期，这可能带来细胞转化或污染的风险。完全消除培养对于避免这些问题将是理想的。在本研究中，我们使用人类抽脂吸出物消化后获得的原始细胞群体，即基质血管成分（SVF），作为组织工程血管移植物（TEVG）丰富的、无需培养的细胞来源。
首先评估SVF细胞和供体配对培养的AD-MSC在血管紧张素II刺激后分化为血管平滑肌细胞（SMC）的能力以及分泌促进SMC迁移的因子（如条件培养基）的能力。接下来，将这两种细胞类型都整合到TEVG支架中，作为主动脉移植物植入Lewis大鼠模型中，并评估其通畅性和组成。
总体而言，人类SVF细胞能够执行与通过培养扩增从同一供体分离的AD-MSC相同的功能。具体而言，SVF中的细胞执行两项重要功能；即，它们能够分化为SMC（SVF钙调蛋白表达：16.4%±7.7%，而AD-MSC为：19.9%±1.7%），并且能够分泌促迁移因子（相对于对照的SVF迁移率：3.1±0.3，而AD-MSC为：2.5±0.5）。SVF细胞也能够接种到可生物降解的、弹性的、多孔支架中，当在体内植入8周时，可生成具有通畅性的TEVG（SVF：通畅率83%，而AD-MSC为：100%通畅率），其中含有主要血管成分（如SMC、内皮细胞、胶原蛋白和弹性蛋白）。
人类脂肪组织可作为无需培养的细胞来源来制造TEVG，为快速生产细胞接种移植物奠定基础。
