Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
12.4
Histological comparison of native skin and cultured skin prepared
for treatment of a pediatric burn patient. (a) Native human skin,
(b) cultured skin substitute
in vitro
shown after 6 days incubation.
The graft was transplanted to the patient after 10 days of
in vitro
incubation. (c) Healed autograft and (d) healed cultured skin substitute
biopsied 3 weeks after grafting to excised full-thickness burn wounds.
Scale bars = 100 µm.
12.3.4 Anatomy of cultured skin substitutes compared to
split-thickness skin graft
In vitro
, CSS resemble split-thickness autograft but exhibit differences in cell
density and extracellular matrix structure (Fig. 12.4(a) and (b)). The dermal compo-
nent of CSS is densely packed with fibroblasts in a porous matrix of thickly
reticulated bovine collagen whereas the dermis is predominantly comprised of
extracellular matrix with few fibroblasts in native human skin (Fig. 12.4(a) and (b)).
After healing, the collagen sponge component of CSS is degraded and new extra-
cellular matrix has been deposited by the fibroblasts yielding a structure that has
become more similar in composition to split-thickness skin (Fig. 12.4(c) and (d)).
12.3.5
Cellular differentiation and gene expression in
cultured skin substitutes
Two biologic changes result from formation of skin substitutes that contain very
high cell densities. First, the proliferation rates of the cells decrease by approxi-
mately an order of magnitude from the maximum rate of log-phase, subconfluent
