Abstract
Maintaining cellular viability in vivo and in vitro is a critical issue in three-dimensional bone tissue engineering. While the use of osteoblast/endothelial cell cocultures on three-dimensional constructs has shown promise for increasing in vivo vascularization, in vitro maintenance of cellular viability remains problematic. This study used perfusion flow to increase osteogenic and angiogenic gene expression, decrease hypoxic gene expression, and increase cell and matrix coverage in osteoblast/endothelial cell co-cultures. Mouse osteoblast-like cells (MC3T3-E1) were cultured alone and in co-culture with mouse microvascular endothelial cells (EOMA) on three-dimensional scaffolds for 1, 2, 7, and 14 days with or without perfusion flow. mRNA levels were determined for several osteogenic, angiogenic, and hypoxia-related genes, and histological analysis was performed. Perfusion flow downregulated hypoxia-related genes (HIF-1α, VEGF, and OPN) at early timepoints, upregulated osteogenic genes (ALP and OCN) at 7 days, and downregulated RUNX-2 and VEGF mRNA at 14 days in osteoblast monocultures. Perfusion flow increased cell number, coverage of the scaffold perimeter, and matrix area in the center of scaffolds at 14 days. Additionally, perfusion flow increased the length of endothelial cell aggregations within co-cultures. These suggest perfusion stimulated co-cultures provide a means of increasing osteogenic and angiogenic activity.
Highlights
While autografts are currently the best available option for bone grafting, the pain and morbidity associated with second surgeries combined with the limited availability of autograft sources highlight the need for alternative grafting materials [1,2,3]
We used perfusion flow to increase the length of endothelial cell aggregations within cocultures, osteoblast-specific gene expression, and the cell number, cell coverage of the scaffold perimeter, and matrix area in the scaffold pores in the center of the scaffold
There is no existing literature on the effects of perfusion flow on cocultures, there have been studies which have achieved vascular-like network formation in static osteoblast/endothelial cell cocultures [10]
Summary
While autografts are currently the best available option for bone grafting, the pain and morbidity associated with second surgeries combined with the limited availability of autograft sources highlight the need for alternative grafting materials [1,2,3]. Implanted bone grafts rely on the ingrowth of existing vessels from host tissue [7, 9], which can take significant amounts of time, leading to poor vascularization and implant rejection [7]. One solution to this clinical problem is to introduce tissue-engineered bone that is prevascularized by a rudimentary vascular system [7, 9, 10, 17,18,19,20]. A common approach to this solution is the co-culture of bone cells and endothelial cells on threedimensional constructs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
