Figure 3.

Vessel recruitment in transplanted cell-sheets and donor cell survial. Serial representative images of functional blood vessels with patent endothelial layers (CD31/lectin double-positive) vessels in the transplanted donor (GFP-positive) cells in sheet-only (a–c) and combined groups (d–f) at 3, 7, and 28 days after each treatment (200×, scale bar = 100 μm). Quantitative analyses of functionally mature vessels in the transplanted area (g) and the donor (GFP-positive) cell presence (h) at 3, 7, and 28 days after each treatment (n = 6 for each group and each time point) (* P < 0.05 versus sheet-only group). At 3 days after treatment, in the sheet-only group, several blood vessels were just located at the border between the sheet and infarct area (a), whereas a large number of functional vessels was detected proximal to the border between the cell-sheet and OM and within the sheet in the combined group (d). Consequently, the combined group had greater numbers of functional blood vessels in the cell-sheet than the sheet-only group at any follow-up point (g). There was no significant difference in the engrafted area at 3 days after transplantation between the groups, while the subsequent changes in each group were apparently distinctive (h). During the 7 days after the treatment, the amount of decrease in the engrafted area was substantially smaller in the combined group than that in the sheet-only group, resulting in 4.3-fold increased retention of donor cells in the former group. This led to the greater donor cell presence in the combined group persistently (at least until day 28), which was consistent with the amount of vessel recruitment in the cell-sheet.