Figure 6.

Delivery of Dkk3 (dickkopf-3) in tissue-engineered vascular grafts (TEVGs) enhances vascular regeneration. Dkk3-loaded TEVGs were implanted into rats to replace the abdominal artery and then harvested 2 wk, 1 mo, and 3 mo post-implantation. A, H&E staining on cross sections of control and Dkk3-loaded TEVGs 3 mo post-implantation. Both grafts are fully cellularized, and no evident intimal hyperplasia is observed. B, Quantification of the inner diameter of the TEVGs at 2 wk, 1 mo, and 3 mo. The inner diameters of the grafts remain unchanged ≤3 mo post-implantation. C, Representative images of the luminal surface of the explanted TEVGs, 3 mo post-implantation, obtained by scanning electronic microscopy. Three locations were selected continuously from the anastomotic sites to the middle of the grafts, and the respective magnified images are shown. The surface of Dkk3-TEVGs throughout the graft is more continuous and homogeneous in comparison with the control group. D, Representative immunofluorescence images of control- and Dkk3-TEVGs showing SMC recruitment by staining the sections with anti–α-SMA (α-smooth muscle actin) and anti-SM-MHC (smooth muscle myosin heavy chain) antibodies. DAPI was used to counterstain the nuclei. E–G, Quantification of smooth muscle regeneration by determination of the total area of α-SMA and of SM-MHC–positive cells in the luminal region (delineated by the white dashed lines) at different time points. Two weeks after implantation, Dkk3-loaded TEVGs display an increase of α-SMA+ cells, compared with control. Over time, the smooth muscle becomes more mature in Dkk3-TEVGs than in control grafts, as the area of SM-MHC+ cells is also increased. The images are representative of 4 grafts for each group. The data are expressed as the mean±SEM of 4 independent experiments. NS indicates nonsignificant. *P<0.05, compared with control group (2-way ANOVA followed by Bonferroni post hoc test for B, E, F, and G).