Improved growth factor directed vascularization into fibrin constructs through inclusion of additional extracellular molecules.
Using the chick chorioallantoic membrane assay (CAM) and a novel histological technique, we investigated the ability of blood vessels to directly invade fibrin-based scaffolds. In our initial experiments utilizing vascular endothelial growth factor (VEGF(165)), we found no direct invasion. Instead, the fibrin was completely degraded and replaced with highly vascularized new tissue. Addition of fibroblast growth factor-2 (FGF-2), bone morphogenic protein-2 (BMP-2), or platelet-derived growth factor-BB (PDGF-BB) to the fibrin construct also did not result in construct vascularization. Because natural and regenerating tissues exhibit complex extracellular matrices (ECMs), we hypothesized that a more complex scaffold may improve blood vessel invasion. Addition of fibronectin, hyaluronic acid, and collagen type I within 20 mg/mL fibrin constructs resulted in no significant improvement. However, the same additive concentrations within 10 mg/mL fibrin constructs resulted in dramatic improvements, specifically with hyaluronic acid. Overall, we believe that these results indicate the importance of structural and functional cues of not only in the initial scaffold but also as the construct is degraded and remodeled. Furthermore, the CAM assay may represent a useful model for understanding ECM interactions as well as for screening and designing tissue-engineered scaffolds.
Smith
J D
JD
Institute for Complex Engineered Systems, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213, USA.
Melhem
M E
ME
Magge
K T
KT
Waggoner
A S
AS
Campbell
P G
PG
D000482:Allantois / Q000098:blood supply; D000818:Animals; D000077214:Becaplermin; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002642:Chick Embryo; D002823:Chorion / Q000098:blood supply; D024042:Collagen Type I / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000494:pharmacology*; D005337:Fibrin; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005353:Fibronectins / Q000494:pharmacology; D005782:Gels; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D006820:Hyaluronic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D024042:Collagen Type I; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D005782:Gels; D006133:Growth Substances; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D000077214:Becaplermin; D005337:Fibrin; D006820:Hyaluronic Acid