Heparin modification of a biomimetic bone matrix modulates osteogenic and angiogenic cell response in vitro

• Published in: European cells & materials Vol. 33; pp. 105 - 120
• Main Authors: Quade, M, Knaack, S, Weber, D, König, U, Paul, B, Simon, P, Rösen-Wolff, A, Schwartz-Albiez, R, Gelinsky, M, Lode, A
• Format: Journal Article
• Language: English
• Published: Switzerland Forum Multimedia Publishing LLC 09-02-2017
• Subjects: Adult; Alkaline Phosphatase - metabolism; angiogenesis; Animals; Biomimetic Materials - pharmacology; Bone Matrix - drug effects; Bone Matrix - metabolism; Cattle; Cell Differentiation - drug effects; Cell Proliferation - drug effects; Cells, Cultured; co-culture; Coculture Techniques; collagen; Collagen - pharmacology; endothelial cells; heparin; Heparin - pharmacology; Human Umbilical Vein Endothelial Cells - cytology; Human Umbilical Vein Endothelial Cells - drug effects; Human Umbilical Vein Endothelial Cells - metabolism; Humans; hydroxyapatite; Male; Materials Testing; mesenchymal stem cells; Mesenchymal Stem Cells - cytology; Mesenchymal Stem Cells - drug effects; Microscopy, Fluorescence; Neovascularization, Physiologic - drug effects; Osteogenesis - drug effects; osteogenic differentiation; Tissue Scaffolds - chemistry
• ISSN: 1473-2262
• 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.