Prefabrication of vascularized porous three-dimensional scaffold induced from rhVEGF(165): a preliminary study in rats.

BACKGROUND/AIMS: Several shortcomings have limited the routine use of autogenous vascularized bone graft. The present study investigates the prefabrication of vascularized scaffold with the desired shape and microarchitecture combined with recombinant human vascular endothelial growth factor 165 (rhVEGF(165)) to mimic autogenous vascularized bone graft. METHODS: Eighty-five porous calcium phosphate cement scaffolds constructed by rapid prototyping technology were divided into four groups: group A [rhVEGF(165)-fibrin sealant (FS) scaffold], group B (hVEGF(165) scaffold), group C (FS scaffold), and group D (scaffold alone). The release of rhVEGF(165) from the scaffolds was examined in vitro. The vessel density, relative functionalized vessels, vessel diameter and relative vessel area were also measured. RESULTS: The sustained release of hVEGF(165) lasted 14 days in the absence of plasmin and 12 days in the presence of plasmin in group A and 10 days in group B. There was no statistical difference between groups A and B at 2 or 4 weeks in terms of vessel density, relative functionalized vessels, vessel diameter, and relative vessel area, as between groups C and D. However, the above parameters were greater in groups A and B than groups C and D. CONCLUSION: The scaffolds with the desired shape and microarchitecture combined with rhVEGF(165) could shorten the time needed for the construction of prefabricated vascularized grafts and accelerate the maturation of the vessels.

Cell proliferation in CPC scaffold with a central channel.

Calcium phosphate cement (CPC) scaffold design should improve nutrient and cell transfer to the scaffold centre. To achieve this goal, a channel network with proper channel diameters should be incorporated into the scaffold. In this study, CPC scaffolds with a single central channel were fabricated indirectly using a stereolithography rapid prototyping (RP) technology. The diameters of the central channels ranged from 402 microm to 1988 microm. These scaffolds were seeded with rabbit marrow stem cells (MSCs) labeling DiI and cultured for 5 days. Cell observation on the wall of the central channels was performed. The data of the experimental point revealed that cell coverage was from approximately 18% (1988 microm) to approximately 35% (592 microm). There was a significant increase from day 1 to day 5 in cell coverage in the same channel. The cell area coverage increased lineally with the central channel diameter when the channel diameter was less than approximately 789 microm. Afterwards (from 789 to 1988 microm), the relationship between cell area coverage and channel diameter was also linear relationship. But the increase was more slowly than before. Preliminary demonstration from the data that the minimum channel diameter required for cell migration into and adhesion on CPC scaffold was approximately 72 microm. These results are promising for the development of optimal scaffold with a three-dimensional channel network.