Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Health System , Washington, DC 20010, United States.
Surface and Trace Chemical Analysis Group, Material Measurement Laboratory, National Institutes of Standards and Technology , Gaithersburg, Maryland 20899, United States.
Biomacromolecules. 2017 Nov 13;18(11):3802-3811. doi: 10.1021/acs.biomac.7b01165. Epub 2017 Oct 16.
Vascular grafts that can support total replacement and maintenance by the body of the injured vessel would improve outcomes of major surgical reconstructions. Building scaffolds using components of the native vessel can encourage biological recognition by native cells as well as mimic mechanical characteristics of the native vessel. Evidence is emerging that incorporating predetermined building-blocks into a tissue engineering scaffold may oversimplify the environment and ignore critical structures and binding sites essential to development at the implant. We propose the development of a 3D-printable and degradable hybrid scaffold by combining polyethylene glycol (PEG)acrylate and homogenized pericardium matrix (HPM) to achieve appropriate biological environment as well as structural support. It was hypothesized that incorporation of HPM into PEG hydrogels would affect modulus of the scaffold and that the modulus and biological component would reduce the inflammatory signals produced from arriving macrophages and nearby endothelial cells. HPM was found to provide a number of tissue specific structural proteins including collagen, fibronectin, and glycosaminoglycans. HPM and PEGacrylate formed a hybrid hydrogel with significantly distinct modulus depending on concentration of either component, which resulted in scaffolds with stiffness between 0.5 and 20 kPa. The formed hybrid hydrogel was confirmed through a reduction in primary amines post-cross-linking. Using these hybrid scaffolds, rat bone marrow derived macrophages developed an M2 phenotype in response to low amounts (0.03%, w/v) of HPM in culture but responded with inflammatory phenotypes to high concentrations (0.3%, w/v). When cultured together with endothelial cells, both M1 and M2 macrophages were detected, along with a combination of both inflammatory and healing cytokines. However, the expression of inflammatory cytokines TNFα and IL1β was significantly (p < 0.05) lower with hybrid hydrogels compared to single component PEG or HPM hydrogels. This reduction in inflammatory cytokines could impact the healing environment that persists at the implantation site. Finally, using this developed hybrid hydrogel, models of neonatal vasculature were manufactured using digital light projection (DLP) 3D printing. The structural control achieved with this novel biomaterial suggests a promising new tool in vascular graft development and research, with potential for complex structures for use in congenital heart defect reconstruction.
能够支持受伤血管的完全替代和维持的血管移植物将改善重大外科重建的结果。使用天然血管的成分构建支架可以鼓励天然细胞的生物识别，并模拟天然血管的机械特性。有证据表明，将预定的构建块纳入组织工程支架可能过于简化环境，并忽略了对植入物发育至关重要的关键结构和结合位点。我们建议通过结合聚乙二醇（PEG）丙烯酰胺和匀化的心包膜基质（HPM）来开发可 3D 打印和可降解的混合支架，以实现适当的生物环境和结构支撑。我们假设将 HPM 纳入 PEG 水凝胶会影响支架的模量，并且模量和生物成分会降低来自到达的巨噬细胞和附近内皮细胞的炎症信号。发现 HPM 提供了许多组织特异性结构蛋白，包括胶原蛋白、纤维连接蛋白和糖胺聚糖。HPM 和 PEGacrylate 形成了一种混合水凝胶，其模量取决于两种成分的浓度，其结果是支架的刚度在 0.5 至 20 kPa 之间。通过交联后初级胺的减少证实了形成的混合水凝胶。使用这些混合支架，在培养物中低浓度（0.03%，w/v）的 HPM 下，大鼠骨髓来源的巨噬细胞发展为 M2 表型，但对高浓度（0.3%，w/v）表现出炎症表型。当与内皮细胞共培养时，检测到 M1 和 M2 巨噬细胞，以及炎症和愈合细胞因子的组合。然而，与单一成分 PEG 或 HPM 水凝胶相比，混合水凝胶中炎症细胞因子 TNFα 和 IL1β 的表达显著（p < 0.05）降低。这种炎症细胞因子的减少可能会影响植入部位持续存在的愈合环境。最后，使用这种开发的混合水凝胶，使用数字光投影（DLP）3D 打印制造了新生儿血管模型。这种新型生物材料所达到的结构控制为血管移植物的开发和研究提供了一种很有前途的新工具，具有用于先天性心脏缺陷重建的复杂结构的潜力。
