We studied the effects of gene transfection of endothelial cells with vascular endothelial growth factor (VEGF) on re-endothelialization and inhibition of in-stent restenosis. Transfected endothelial cells (ECs) exposed to different VEGF levels were seeded on a stent surface for evaluation in vitro. VEGF121(++) ECs and VEGF121(--) ECs were established using lentiviral-mediated HUVECs transfection. VEGF RNA transcription level and VEGF protein expression were detected by qPCR, Western blot, and ELISA. Methyl thiazolyl tetrazolium (MTT) assay, wound healing assay, and in vitro HUVEC tube formation assay showed that VEGF overexpression promoted cell proliferation, migration, and endothelial capillary-like tube formation. Downregulation of VEGF expression inhibited these activities. Using a rotational culturing system, cells tightly adhered on the stent surface. Stents seeded with transfected ECs at different VEGF levels were implanted in abdominal aortas of New Zealand white rabbits to study re-endothelialization and inhibition of in-stent restenosis. Stents with cells exposed to excess VEGF expression were almost completely covered with cells after stent implantation for 1 week (w). In the VEGF interference group this process was delayed over 4 w due to RNAi-mediated silencing of VEGF. Cryosectioning after 12 w showed that stents seeded with HUVECs exposed to excess VEGF expression significantly reduced the neointima area and stenosis when compared with bare metal stents and stents from the VEGF interference group. Transgenic HUVECs were not found in tissues of experimental animals. Furthermore, cells from these tissues were similar to those from normal tissue. In conclusion, VEGF-mediated endothelialization was found. Furthermore, ECs exposed to VEGF overexpression reduced neointimal hyperplasia, promoted endothelialization, and reduced in-stent restenosis.

a) Diagram depicting the preparation of drug delivery system of PLGA-lysoGM1/DOX micelles. b) Schematic illustration of micelles elicited antitumor. c) Micelles cross BBB via micropinocytosis and autophagy/lysosomal pathways.

In this study, we designed a novel drug-eluting coating for vascular implants consisting of a core coating of the antiproliferative drug docetaxel (DTX) and a shell coating of the platelet glycoprotein IIb/IIIa receptor monoclonal antibody SZ-21. The core/shell structure was sprayed onto the surface of 316L stainless steel stents using a coaxial electrospray process with the aim of creating a coating that exhibited a differential release of the two drugs. The prepared stents displayed a uniform coating consisting of nano/micro particles. In vitro drug release experiments were performed, and we demonstrated that a biphasic mathematical model was capable of capturing the data, indicating that the release of the two drugs conformed to a diffusion-controlled release system. We demonstrated that our coating was capable of inhibiting the adhesion and activation of platelets, as well as the proliferation and migration of smooth muscle cells (SMCs), indicating its good biocompatibility and anti-proliferation qualities. In an in vivo porcine coronary artery model, the SZ-21/DTX drug-loaded hydrophobic core/hydrophilic shell particle coating stents were observed to promote re-endothelialization and inhibit neointimal hyperplasia. This core/shell particle-coated stent may serve as part of a new strategy for the differential release of different functional drugs to sequentially target thrombosis and in-stent restenosis during the vascular repair process and ensure rapid re-endothelialization in the field of cardiovascular disease.

An ideal vascular stent would both inhibit in-stent restenosis (ISR) and promote rapid re-endothelialization. In the current study, the performance of arsenic trioxide (ATO)-drug eluting stent (AES) is compared with the bare metal stent, poly-lactic-co-glycolic acid-coating metal stent, and rapamycin-drug eluting stent (RES). In vivo AES is shown to prevent neointimal hyperplasia more efficiently than the others when implanted into the carotid arteries of rabbits. Moreover, AES promotes endothelial cells proliferation and re-endothelialization more quickly than RES. In vitro ATO exposure significantly increases the viability, proliferation, adhesion, and spreading of primary porcine coronary artery endothelial cells (PCAECs), which are critical for endothelialization. However, ATO exposure reduces the viability of porcine coronary artery smooth muscle cells (PCASMCs). The evaluation of mitochondrial morphology, membrane potential, and function demonstrates that ATO at 2 µmol L causes enlargement of the mitochondrion, enhancement of mitochondrial membrane potential, and adenosine triphosphate (ATP) production in PCAECs but not in PCASMCs. Thus, both in vivo and in vitro studies demonstrate that AES is an effective strategy for rapid re-endothelialization and inhibition of ISR.