Tissue Bioengineering Laboratory (BioTis), Inserm U1026, University of Bordeaux, Bordeaux, France.
Univ. Bordeaux, CNRS, Bordeaux INP, LCPO, UMR 5629, F-33600 Pessac, France.
Acta Biomater. 2019 Nov;99:154-167. doi: 10.1016/j.actbio.2019.08.028. Epub 2019 Aug 16.
Despite significant progress in the field of biomaterials for bone repair, the lack of attention to the vascular and nervous networks within bone implants could be one of the main reasons for the delayed or impaired recovery of bone defects. The design of innovative biomaterials should improve the host capacity of healing to restore a functional tissue, taking into account that the nerve systems closely interact with blood vessels in the bone tissue. The aim of this work is to develop a cell-free and growth factor-free hydrogel capable to promote angiogenesis and innervation. To this end, we have used elastin-like polypeptides (ELPs), poly(ethylene glycol) (PEG) and increasing concentrations of the adhesion peptide IKVAV (25% (w/w) representing 1.7 mM and 50% (w/w) representing 4.1 mM) to formulate and produce hydrogels. When characterized in vitro, hydrogels have fine-tunable rheological properties, microporous structure and are biocompatible. At the biological level, 50% IKVAV composition up-regulated Runx2, Osx, Spp1, Vegfa and Bmp2 in mesenchymal stromal cells and Tek in endothelial cells, and sustained the formation of long neurites in sensory neurons. When implanted subcutaneously in mice, hydrogels induced no signals of major inflammation and the 50% IKVAV composition induced higher vessel density and formation of nervous terminations in the peripheral tissue. This novel composite has important features for tissue engineering, showing higher osteogenic, angiogenic and innervation potential in vitro, being not inflammatory in vivo, and inducing angiogenesis and innervation subcutaneously. STATEMENT OF SIGNIFICANCE: One of the main limitations in the field of tissue engineering remains the sufficient vascularization and innervation during tissue repair. In this scope, the development of advanced biomaterials that can support these processes is of crucial importance. Here, we formulated different compositions of Elastin-like polypeptide-based hydrogels bearing the IKVAV adhesion sequence. These compositions showed controlled mechanical properties, and were degradable in vitro. Additionally, we could identify in vitro a composition capable to promote neurite formation and to modulate endothelial and mesenchymal stromal cells gene expression, in view of angiogenesis and osteogenesis, respectively. When tested in vivo, it showed no signs of major inflammation and induced the formation of a highly vascularized and innervated neotissue. In this sense, our approach represents a potential advance in the development of new strategies to promote tissue regeneration, taking into account both angiogenesis and innervation.
尽管在骨修复生物材料领域取得了重大进展，但对骨植入物内血管和神经网络的关注不足，可能是骨缺损恢复延迟或受损的主要原因之一。创新生物材料的设计应提高宿主的愈合能力，以恢复功能性组织，同时考虑到神经系统与骨组织中的血管密切相互作用。本工作的目的是开发一种无细胞和无生长因子的水凝胶，以促进血管生成和神经支配。为此，我们使用了弹性蛋白样多肽（ELP）、聚乙二醇（PEG）和增加浓度的粘附肽 IKVAV（25%（w/w）代表 1.7mM 和 50%（w/w）代表 4.1mM）来配方和生产水凝胶。在体外进行特征分析时，水凝胶具有可精细调节的流变特性、微孔结构且具有生物相容性。在生物学水平上，50%IKVAV 组成上调间充质基质细胞中的 Runx2、Osx、Spp1、Vegfa 和 Bmp2 以及内皮细胞中的 Tek，并维持感觉神经元中长轴突的形成。当皮下植入小鼠时，水凝胶不会引起主要炎症信号，而 50%IKVAV 组成会诱导更高的血管密度和外周组织中神经末梢的形成。这种新型复合材料具有组织工程的重要特征，在体外表现出更高的成骨、血管生成和神经支配潜力，在体内无炎症反应，并能在皮下诱导血管生成和神经支配。
组织工程领域的主要限制之一仍然是组织修复过程中足够的血管生成和神经支配。在这方面，开发能够支持这些过程的先进生物材料至关重要。在这里，我们配方了不同组成的基于弹性蛋白样多肽的水凝胶，其中包含 IKVAV 粘附序列。这些组成具有可控制的机械性能，并可在体外降解。此外，我们可以识别出一种能够促进神经突形成并分别调节血管生成和成骨的组成，以促进血管生成和骨生成。当在体内进行测试时，它没有表现出主要炎症的迹象，并诱导了高度血管化和神经支配的新组织的形成。从这个意义上说，我们的方法代表了在开发新策略以促进组织再生方面的潜在进展，同时考虑到血管生成和神经支配。
