Seliktar D, Zisch A H, Lutolf M P, Wrana J L, Hubbell J A
Institute for Biomedical Engineering, Swiss Federal Institute of Technology and University of Zurich, Moussonstrasse 18, CH-8044 Zurich, Switzerland.
J Biomed Mater Res A. 2004 Mar 15;68(4):704-16. doi: 10.1002/jbm.a.20091.
We sought to develop bioactive hydrogels to facilitate arterial healing, e.g., after balloon angioplasty. Toward this end, we developed a new class of proteolytically sensitive, biologically active polyethylene glycol (PEG)-peptide hydrogels that can be formed in situ to temporarily protect the arterial injury from blood contact. Furthermore, we incorporated endothelial cell-specific biological signals with the goal of enhancing arterial reendothelialization. Here we demonstrate efficient endothelial cell anchorage and activation on PEG hydrogel matrices modified by conjugation with both the cell adhesive peptide motif RGD and an engineered variant of vascular endothelial growth factor (VEGF). By crosslinking peptide sequences for cleavage by MMP-2 into the polymer backbone, the hydrogels became sensitive to proteolytic degradation by cell-derived matrix metalloproteinases (MMPs). Analysis of molecular hallmarks associated with endothelial cell activation by VEGF-RGD hydrogel matrices revealed a 70% increase in production of the latent MMP-2 zymogen compared with PEG-peptide hydrogels lacking VEGF. By additional provision of transforming growth factor beta1 (TGF-beta1) within the PEG-peptide hydrogel, conversion of the latent MMP zymogen into its active form was demonstrated. As a result of MMP-2 activation, strongly enhanced hydrogel degradation by activated endothelial cells was observed. Our data illustrate the critical importance of growth factor activities for remodeling of synthetic biomaterials into native tissue, as it is desired in many applications of regenerative medicine. Functionalized PEG-peptide hydrogels could help restore the native vessel wall and improve the performance of angioplasty procedures.
我们试图开发生物活性水凝胶以促进动脉愈合，例如在球囊血管成形术后。为此，我们开发了一类新型的对蛋白水解敏感的生物活性聚乙二醇（PEG）-肽水凝胶，其可原位形成以暂时保护动脉损伤部位不与血液接触。此外，我们引入了内皮细胞特异性生物信号，目的是增强动脉再内皮化。在此，我们展示了在与细胞黏附肽基序RGD和血管内皮生长因子（VEGF）的工程变体共轭修饰的PEG水凝胶基质上，内皮细胞能有效锚定和激活。通过将可被基质金属蛋白酶-2（MMP-2）切割的肽序列交联到聚合物主链中，这些水凝胶对细胞衍生的基质金属蛋白酶（MMPs）的蛋白水解降解变得敏感。对与VEGF-RGD水凝胶基质介导的内皮细胞激活相关的分子特征分析显示，与缺乏VEGF的PEG-肽水凝胶相比，潜伏性MMP-2酶原的产生增加了70%。通过在PEG-肽水凝胶中额外提供转化生长因子β1（TGF-β1），证明了潜伏性MMP酶原向其活性形式的转化。由于MMP-2的激活，观察到活化的内皮细胞对水凝胶的降解作用大大增强。我们的数据说明了生长因子活性对于将合成生物材料重塑为天然组织的关键重要性，这在再生医学的许多应用中都是期望的。功能化的PEG-肽水凝胶有助于恢复天然血管壁并改善血管成形术的效果。
