Biofunctionalization with RGD peptides and vascular endothelial growth factor enhances endothelialization of biodegradable small-diameter vascular grafts

Tissue-engineered vascular grafts are the perfect candidates as vascular conduits for cardiovascular bypass or arterial replacement surgery. Aim: To compare efficiency of the grafts blended of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with poly(е-caprolactone) and optionally modified with either vascular endothelial growth factor (VEGF) or RGD peptides. Materials and Methods. Electrospun, 2 mm diameter grafts optionally modified with either VEGF or RGD peptides were implanted into rat abdominal aorta (n=20 per each group). In 1, 3, 6, 9, or 12 months, one-fifth of rats in each group were sacrificed (n=4 per each time point) for the following histological and immunofluorescence examination of the explanted grafts. Results. At 12 months postimplantation, modification with either VEGF or RGD peptides induced formation of endothelial cell monolayer and a basement membrane-like structure in three-fourths of the grafts, which was three-fold higher compared to unmodified grafts. Furthermore, we detected CD34-positive cells, i.e. endothelial progenitor cells, as early as 1 month postimplantation in both VEGF- and RGD-treated grafts.