Department of Biomedical Engineering, University of Kansas, Lawrence, KS 66045, United States of America.
Biomed Mater. 2020 Jul 27;15(5):055006. doi: 10.1088/1748-605X/ab8e98.
A tissue engineered vessel has the potential to provide an alternative small diameter vascular graft for patients with cardiovascular disease in need of surgical revascularization. In this study, a polyglycolic acid (PGA) electrospun scaffold seeded with human dermal fibroblasts was stimulated with circumferential mechanical stretch by a pulsatile perfusion system. The PGA scaffold was fabricated using a custom electrospinning set-up to co-electrospray a sacrificial polyethylene oxide microparticle to increase pore size and bulk porosity. The tissue engineered vessel exposed to circumferential mechanical stretch was compared to an engineered vessel cultured under static conditions without any mechanical stimulation. The histology cross-sections demonstrated a similar thickness of engineered vessels with mechanical stretch and static, but on Masson's Trichrome stain there was nearly twice the amount of staining for collagen. The collagen content was quantified, and the collagen content was 60% greater in the human tissue engineered vessel exposed to mechanical stretch compared to the static vessel. The total collagen cross-linking was similar, but on a per collagen basis there was significantly more cross-linking in the static vessel over the stretch vessel. The stress-strain curve of the tissue engineered vessel with mechanical stretch demonstrated a statistically significantly greater ultimate tensile strength (UTS) of 1.86 ± 0.14 MPa (n = 6) and elastic modulus (EM) of 7.62 ± 0.39 MPa (n = 6) versus the static engineered vessel UTS of 0.31 ± 0.07 MPa (n = 5) and EM of 1.37 ± 0.21 MPa (n = 5). The primary determinant of the mechanical properties of the tissue engineered vessel correlated to the collagen content with minimal contribution of the collagen cross-linking. Therefore, the versatile properties of an electrospun scaffold are ideal in combination with a biomimetic culture system to generate a tissue engineered vessel composed of extracellular matrix suitable as a vascular graft.
组织工程血管有潜力为需要手术血运重建的心血管疾病患者提供替代小直径血管移植物。在这项研究中，用人真皮成纤维细胞接种的聚乙醇酸（PGA）电纺支架通过脉动灌注系统接受周向机械拉伸刺激。PGA 支架是使用定制的电纺装置制造的，该装置共同电喷射牺牲性聚氧化乙烯微粒以增加孔径和体相孔隙率。与在没有任何机械刺激的静态条件下培养的工程血管相比，暴露于周向机械拉伸的组织工程血管。组织工程血管的组织学横截面显示，机械拉伸和静态的工程血管具有相似的厚度，但在 Masson 三色染色上，胶原染色的量几乎增加了两倍。对胶原含量进行了定量，与静态血管相比，机械拉伸的人组织工程血管中的胶原含量增加了 60%。总的胶原交联相似，但基于每胶原的基础，静态血管的交联明显多于拉伸血管。机械拉伸的组织工程血管的应力-应变曲线显示出统计学上显著更高的极限拉伸强度（UTS）为 1.86 ± 0.14 MPa（n = 6）和弹性模量（EM）为 7.62 ± 0.39 MPa（n = 6），而静态工程血管的 UTS 为 0.31 ± 0.07 MPa（n = 5）和 EM 为 1.37 ± 0.21 MPa（n = 5）。组织工程血管机械性能的主要决定因素与胶原含量相关，胶原交联的贡献最小。因此，电纺支架的多功能特性与仿生培养系统相结合，可生成由细胞外基质组成的组织工程血管，适合作为血管移植物。
