Artificial small-diameter vascular grafts remain an unmet need in modern medicine, due to the thrombosis and neointimal hyperplasia that plague currently available synthetic devices. Tissue engineering techniques, including in vitro endothelialization, could offer a solution to this problem. A potential minimally invasive source of patient autologous endothelium is endothelial colony-forming cells (ECFCs), endothelial-like outgrowth products of circulating progenitors. While ECFCs respond to shear stress similar to mature endothelial cells (ECs), their response to luminal topographic micropatterning (TMP), a biomaterial modification with the potential to flow-independently, enhance the attachment, migration, gene expression, and function of mature ECs, remains unstudied. In this study, case-matched carotid endothelial cells (CaECs) and blood-derived ECFCs are statically cultured on polyurethane substrates with micropatterned pitches (pitch = peak to peak distance) ranging from 3–to 14 μm. On all pattern pitches tested, both CaECs and ECFCs showed significant and robust alignment to the angle of the micropatterns. Using a novel cell-by-cell image analysis technique, it was found that actin fibers similarly and significantly aligned to the angle of micropatterned features on all pitches tested. Microtubules analyzed through the same novel approach showed significant alignment on most pitches examined, with a greater variation in fiber angle overall. Interestingly, only CaECs showed significant cellular elongation, and notably to a lower degree than previously seen either in vivo due to flow or in vitro due to spatial growth restriction micropatterning, but consistent with earlier studies of TMP. Neither cell type displayed any significant micropattern-driven changes in the expression of KLF-2 or the downstream adhesion molecules it regulates. These results demonstrate that TMP flow-independently affects ECFC morphology, but that alignment alone is insufficient to drive protective changes in EC and ECFC function.

中文翻译：

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地形微图案对内皮集落形成细胞的影响

由于困扰目前可用的合成装置的血栓形成和新内膜增生，人造小直径血管移植物在现代医学中仍然是一个未满足的需求。组织工程技术，包括体外内皮化，可以解决这个问题。患者自体内皮的潜在微创来源是内皮集落形成细胞 (ECFC)，即循环祖细胞的内皮样生长产物。虽然 ECFC 对剪切应力的反应与成熟内皮细胞 (EC) 相似，但它们对腔内拓扑微图案 (TMP) 的反应是一种具有独立流动潜力的生物材料修饰，可增强成熟 EC 的附着、迁移、基因表达和功能, 仍未研究。在这项研究中，病例匹配的颈动脉内皮细胞 (CaECs) 和血液衍生的 ECFCs 在聚氨酯基质上静态培养，微图案间距（间距 = 峰到峰距离）范围为 3 至 14 μm。在所有测试的图案间距上，CaECs 和 ECFCs 都显示出与微图案角度的显着且稳健的对齐。使用一种新的逐细胞图像分析技术，发现肌动蛋白纤维与所有测试间距上的微图案特征的角度相似且显着对齐。通过相同的新方法分析的微管在所检查的大多数间距上显示出显着的对齐，总体上纤维角度的变化更大。有趣的是，只有 CaECs 显示出显着的细胞伸长率，并且明显低于以前看到的任何一种 通过相同的新方法分析的微管在所检查的大多数间距上显示出显着的对齐，总体上纤维角度的变化更大。有趣的是，只有 CaECs 显示出显着的细胞伸长率，并且明显低于以前看到的任何一种 通过相同的新方法分析的微管在所检查的大多数间距上显示出显着的对齐，总体上纤维角度的变化更大。有趣的是，只有 CaECs 显示出显着的细胞伸长率，并且明显低于以前看到的任何一种体内由于流动或体外由于空间生长限制微图案，但与 TMP 的早期研究一致。这两种细胞类型都没有表现出任何显着的微模式驱动的 KLF-2 表达或其调节的下游粘附分子的变化。这些结果表明，TMP 流动独立地影响 ECFC 形态，但仅靠对齐不足以驱动 EC 和 ECFC 功能的保护性变化。