Quade M, Knaack S, Weber D, König U, Paul B, Simon P, Rösen-Wolff A, Schwartz-Albiez R, Gelinsky M, Lode A
Centre for Translational Bone, Joint and Soft Tissue Research, University Hospital Carl Gustav Carus and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
Eur Cell Mater. 2017 Feb 9;33:105-120. doi: 10.22203/eCM.v033a08.
In this study, the effect of heparin-modified collagen type I/hydroxyapatite (HA) nanocomposites on key processes of bone regeneration - osteogenesis and angiogenesis - was characterised in vitro. Two approaches were applied for heparin modification: it was either integrated during material synthesis (in situ) or added to the porous scaffolds after their fabrication (post). Cultivation of human bone marrow-derived stromal cells (hBMSC), in heparin-modified versus heparin-free scaffolds, revealed a positive effect of the heparin modification on their proliferation and osteogenic differentiation. The amount of heparin rather than the method used for modification influenced the cell response favouring proliferation at smaller amount (30 mg/g collagen) and differentiation at larger amount (150 mg/g collagen). A co-culture of human umbilical vein endothelial cells (HUVEC) and osteogenically induced hBMSC was applied for in vitro angiogenesis studies. Pre-vascular networks have formed in the porous structure of scaffolds which were not modified with heparin or modified with a low amount of heparin (30 mg/g collagen). The modification with higher heparin quantities seemed to inhibit tubule formation. Pre-loading of the scaffolds with VEGF influenced formation and stability of the pre-vascular structures depending on the presence of heparin: In heparin-free scaffolds, induction of tubule formation and sprouting was more pronounced whereas heparin-modified scaffolds seemed to promote stabilisation of the pre-vascular structures. In conclusion, the modification of mineralised collagen with heparin by using both approaches was found to modulate cellular processes essential for bone regeneration; the amount of heparin has been identified to be crucial to direct cell responses.
在本研究中，对肝素修饰的I型胶原/羟基磷灰石（HA）纳米复合材料在骨再生关键过程——成骨和血管生成方面的作用进行了体外表征。采用了两种肝素修饰方法：一种是在材料合成过程中（原位）整合，另一种是在多孔支架制备后添加（后修饰）。在肝素修饰和未修饰肝素的支架中培养人骨髓来源的基质细胞（hBMSC），结果显示肝素修饰对其增殖和成骨分化具有积极作用。肝素的用量而非修饰方法影响细胞反应，较小用量（30 mg/g胶原）时有利于增殖，较大用量（150 mg/g胶原）时有利于分化。将人脐静脉内皮细胞（HUVEC）与经成骨诱导的hBMSC共培养用于体外血管生成研究。在未用肝素修饰或用少量肝素（30 mg/g胶原）修饰的支架多孔结构中形成了预血管网络。较高肝素用量的修饰似乎抑制了小管形成。根据肝素的存在情况，用VEGF预加载支架会影响预血管结构的形成和稳定性：在未修饰肝素的支架中，小管形成和发芽的诱导更为明显，而肝素修饰的支架似乎促进了预血管结构的稳定。总之，发现通过两种方法用肝素修饰矿化胶原可调节骨再生所必需的细胞过程；已确定肝素用量对指导细胞反应至关重要。
