Co-Electrospun Blends of PLGA, Gelatin and Elastin as Nonthrombogenic Scaffolds for Vascular Tissue Engineering

Coronary artery disease is the leading cause of death amongst the cardiovascular diseases (∼51%), which requires off-the-shelf available, nonthrombogenic small diameter grafts. We hypothesize that co-electrospun suitable blends of natural and synthetic polymers might yield a nonthrombogenic scaffold for application in vascular tissue engineering. In this study, we evaluated the physical and biological properties of nine co-electrospun blends of PLGA, gelatin and elastin blend (PGE) fibers by systematically varying the relative ratios of poly(lactide-co-glycolide) (PLGA) and gelatin. The suitability of the composites as vascular scaffolds was assessed in vitro by evaluating their interactions with 2 different human endothelial cells (EA.hy926, EC and human aortic endothelial cells), and bovine aortic smooth muscle cells (SMCs). PGE blend fibers supported ECs and SMCs initial attachment and proliferation with small variances in EC morphology and cytoskeletal spreading for different PGE compositions, but did not show differences upon confluence. In addition, PGE scaffolds uniquely supported EC monolayer formation on the surface while concomitantly fostering penetration of SMC cells into the PGE scaffolds. To investigate differential gene expression under the influence of underlying extracellular matrix, we used a focused adhesion/ matrix remodeling-specific PCR array to study human aortic endothelial cells (HAECs) cultured on PGE321, the blend with mechanical properties most favorable for vascular applications, in comparison to those on gelatin-coated coverslips. In addition, we compared tissue factor (TF) mRNA and protein activity levels of confluent HAEC monolayers cultured on PGE321 with those on various natural proteins. Our results indicate that HAECs seeded on PGE321 and gelatin shared a similar expression pattern of ECM and adhesion molecules within 24 hours. Comparable TF mRNA and activity levels of HAEC monolayers (24 h post-seeding) at basal and stimulated conditions were also observed on PGE321 in comparison to those on gelatin-coated coverslips. Our data demonstrate that PGE321 is a suitable scaffold for application in vascular tissue engineering by supporting a nonthrombogenic and physiologically competent endothelium.