Evaluation of Remodeling and Regeneration of Electrospun PLGA@PCL/Elastin Small-Diameter Vascular Grafts In Vivo

Bypass vascular grafting is an effective treatment for cardiovascular disease. Currently, small-diameter vascular grafts (SDVGs, inner diameter <6 mm) for peripheral revascularization, especially for lower limb revascularization, are in high demand. Previously, we prepared and investigated PLGA@PCL SDVGs with core/shell fibers. In this study, PLGA@PCL/elastin core/shell fibers (PCEs) SDVGs were further prepared by electrospinning, so as to enhance the vascular regeneration performance through the introduction of exogenous soluble elastin. The cross-linking effects of elastin with different cross-linking reagents on PCEs SDVGs were subsequently explored. Among them, PCEs SDVGs cross-linked with 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide (EDCI) and N-hydroxysuccinimide (NHS) retained the most soluble elastin content and achieved a compliance of 1.74 ± 0.62%/mmHg × 10^-2, a bursting pressure of 1750 mmHg, and a tensile strength of 2.09 ± 0.51 MPa, which are mostly close to those of human saphenous vein. Subsequently, in vivo transplantation in the abdominal aorta showed that all implanted SDVGs cross-linked by EDC/NHS (PCEsEN) remained patent without aneurysm formation. Histological staining results further showed that the introduction of elastin not only promoted the degradation of SDVGs but also accelerated the formation of neointimal tissue and suppressed the calcification. Thus, PCEsEN shows promising potential to be translated into SDVGs in clinic.