Figure 1.
Compression device on the human full-thickness skin graft delivering a pressure of 150 mmHg.
A, three cycles of compression (8 h of clamping after 16 h of no compression) were delivered to the human skin graft to generate the pressure ulcer. B, schematic representation of the compression device. F = force generated by the spring. R = force generated by the compression device.
Figure 2.
Photographic evolution of the human skin graft in mice.
A, human full-thickness skin graft evolution from the control group. (a) Day of surgery. (b) Day 6 after surgery. (c) Day 30 after surgery. (d) Day 60 after surgery. Macroscopically, the graft was soft and pliable, resembling normal human skin. Note that the stable human full-thickness skin graft from the control groups took successfully. B, human full-thickness skin graft evolution after placing the compression device for three cycles. (a) Day before the compression device was applied. (b) Day 1 after the three compression cycles. The human skin graft remained folded with a hemorrhagic area in the center of the fold (see arrow). (c) Day 7 after compression cycles. Irreversible damage characterizing a PU can be observed. The center of the fold was occupied by a necrotic and hemorrhagic area (see arrow). (d) Day 31 after the compression cycles. Crusty remnants were observed. (e) Day 40 after compression cycles. Only a small central crusted island could be observed. (f) Day 130 after compression cycles. Complete regeneration of the graft was noticed.
Figure 3.
Area in cm2 of the human full thickness skin graft on the back of the mice during the first 120 days after surgery.
A significant reduction of the skin graft can be observed during the first week after the transplantation.
Figure 4.
Histological analysis (H&E at 5x, panoramic view) of the mouse and human skin.
A, human skin taken 60 days after placement of the human full-thickness skin graft. A clear delimitation between the normal human skin (*) and the mouse skin (m) can be observed. The transition between human and mouse skin has been marked with dotted lines. B, pressure ulcer over the human full-thickness skin graft. 7 days post-compression cycles. Pressure ulcer tissue can be observed as a consequence of mechanical damage. Four zones can be differentiated: m = receptor mouse skin; zone 1 = normal human skin; zone 2 = medium damage human skin; zone 3 = maximal damage human skin. C, 130 days post-compression cycles. A central area with a stratified epithelium over a non-papillary neodermis (+), a homogeneous and uniform human skin (*) and receptor mouse skin tissue (m) can be observed.
Figure 5.
Fluorescence in situ hybridization (FISH) for chromosomes XX and XY.
Chromosomes XX from the female human skin and chromosome XY from the male mouse skin were found as green-green dots (X-X, see green arrow) and green-red dots (X-Y, see red arrow). Most cells showing the Y chromosome (red dot) appeared to correspond to mouse cells infiltrating the human tissue.
Table 1.
Characteristics of the different published pressure ulcer models.