Vascularization of Natural and Synthetic Bone Scaffolds

Xi Liu, Adam E. Jakus, Mehmet Kural, Hong Qian, Alexander Engler, Mahboobe Ghaedi, Ramille Shah, Derek M. Steinbacher*, Laura E. Niklason

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Vascularization of engineered bone tissue is critical for ensuring its survival after implantation. In vitro pre-vascularization of bone grafts with endothelial cells is a promising strategy to improve implant survival. In this study, we pre-cultured human smooth muscle cells (hSMCs) on bone scaffolds for 3 weeks followed by seeding of human umbilical vein endothelial cells (HUVECs), which produced a desirable environment for microvasculature formation. The sequential cell-seeding protocol was successfully applied to both natural (decellularized native bone, or DB) and synthetic (3D-printed Hyperelastic “Bone” scaffolds, or HB) scaffolds, demonstrating a comprehensive platform for developing natural and synthetic-based in vitro vascularized bone grafts. Using this sequential cell-seeding process, the HUVECs formed lumen structures throughout the DB scaffolds as well as vascular tissue bridging 3D-printed fibers within the HB. The pre-cultured hSMCs were essential for endothelial cell (EC) lumen formation within DB scaffolds, as well as for upregulating EC-specific gene expression of HUVECs grown on HB scaffolds. We further applied this co-culture protocol to DB scaffolds using a perfusion bioreactor, to overcome the limitations of diffusive mass transport into the interiors of the scaffolds. Compared with static culture, panoramic histological sections of DB scaffolds cultured in bioreactors showed improved cellular density, as well as a nominal increase in the number of lumen structures formed by ECs in the interior regions of the scaffolds. In conclusion, we have demonstrated that the sequential seeding of hSMCs and HUVECs can serve to generate early microvascular networks that could further support the in vitro tissue engineering of naturally or synthetically derived bone grafts and in both random (DB) and ordered (HB) pore networks. Combined with the preliminary bioreactor study, this process also shows potential to generate clinically sized, vascularized bone scaffolds for tissue and regenerative engineering.

Original languageEnglish (US)
Pages (from-to)1269-1280
Number of pages12
JournalCell Transplantation
Volume27
Issue number8
DOIs
StatePublished - Aug 1 2018

Keywords

  • 3D printing bone scaffold
  • bone regeneration
  • decellularized bone scaffold
  • endothelial cell
  • vascularized bone graft

ASJC Scopus subject areas

  • Biomedical Engineering
  • Cell Biology
  • Transplantation

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  • Cite this

    Liu, X., Jakus, A. E., Kural, M., Qian, H., Engler, A., Ghaedi, M., Shah, R., Steinbacher, D. M., & Niklason, L. E. (2018). Vascularization of Natural and Synthetic Bone Scaffolds. Cell Transplantation, 27(8), 1269-1280. https://doi.org/10.1177/0963689718782452