A novel PDGF receptor inhibitor-eluting stent attenuates in-stent neointima formation in a rabbit carotid model

Figures

• 

  Figure 1.. (A) Cumulative release profile of sunitinib from sunitinib-eluting stents. (B) Stent implantation. (C) Postoperative diagnostic angiography and (D) Doppler ultrasound demonstrated the patency of the stent grafts. The arrow indicates the position of the stent.

• 

  Figure 2.. (A) Representative images of hematoxylin and eosin staining of cross-sections one and three months following implantation. (B) Average intimal thickness and the areas of neointima of BMS and STES groups at one and three months post implantation (n=6 per group). The STES group had reduced intimal thickness and area compared with the BMS group. *P<0.05. (C) Re-endothelialization assessed by en face scanning electron microscopy of the arteries one month following stent implantation. The BMS and the STES were efficient at inducing re-endothelialization. BMS, bare-metal stent; STES, sunitinib-eluting stent; N, neointima; M, media; S, strut.

• 

  Figure 3.. (A) Effect of sunitinib on the proliferation of RSMCs and RECs. Sunitinib inhibited proliferation and DNA synthesis in RSMCs, but not in RECs. *P<0.05 and **P<0.01 vs. vehicle. (B) Effect of sunitinib on apoptosis and necrosis of PDGF-BB-treated RSMCs. Apoptotic (annexin V+/PI−) or necrotic (annexin V+/PI+) cells were identified by flow cytometry. *P<0.05 and **P<0.01 vs. vehicle. (C) Representative images reveal that greater numbers of cells attach to the BMS compared with the STES. Cell nuclei were stained blue with DAPI. Magnification, ×400. *P<0.05 vs. BMS. (D) Representative images reveal that sunitinib attenuated PDGF-induced migration of RSMCs in a scratch wound assay in a dose-dependent manner. Solid lines represent the edges of cell migration. Magnification, ×40. (E) Effect of sunitinib on α-SMA cytoskeleton polymerization in RSMCs; α-SMA was stained with fluorescein isothiocyanate (green), and nuclei were stained with DAPI (blue). Magnification, ×400. RMSCs, rat smooth muscle cells; RECs, rat endothelial cells; PDGF, platelet-derived growth factor; PI, propidium iodide; BMS, bare-metal stent; STES, sunitinib-eluting stent; DAPI, 4′,6-diamidino-2-phenylindole; α-SMA,…

• 

  Figure 4.. The inhibitory effect of sunitinib on PDGF-induced intracellular signaling in vitro and in vivo. (A) Left panel: RSMCs were stimulated with 20 ng/ml PDGF-BB and 0–10 µM sunitinib in serum-free medium for 24 h. Western blot analysis of p-ERK, p-PDGFR and GAPDH, which served as a loading control, was performed. (B) Quantification of western blots demonstrated that protein expression levels of p-PDGFR were decreased by sunitinib treatment in a dose-dependent manner, and PDGF-induced downstream p-ERK protein expression levels were suppressed. *P<0.05 and **P<0.01 vs. vehicle. (C) The media, adventitia and neointima were harvested from rabbits implanted with BMS or STES, and western blot analysis of p-ERK was performed, with GAPDH serving as a loading control. (D) Quantification of western blots demonstrated that protein expression levels of p-ERK in the neointima were significantly decreased in STES compared with BMS. *P<0.05 vs. BMS Neo. PDGF, platelet-derived growth factor; RMSCs, rat smooth muscle cells; p-, phosphorylated; ERK, extracellular signal-regulated kinase; PDGFR, PDGF receptor; BMS, bare-metal stent; STES, sunitinib-eluting stent; Med, media; A, adventitia; Neo,…