Biomedical Engineering Reference
In-Depth Information
of Matriderm™ and Integra™, both covered with STSG in the form of neonatal rat
epidermis, was based on a one-step procedure (matrix covered with STSG) to treat
full-thickness skin defects in a rat model. The study led to the conclusion that the
neodermis synthesized in the presence of Matriderm™ was thinner than the one
synthesized in the presence of Integra™, hypothetically due to faster degradation of
Matriderm™. Other parameters of the outcome (vascularization, collagen deposi-
tion, and inflammatory response) were reported to be similar for the two matrices
(Böttcher-Haberzeth et al. 2012).
5.4.4
Evidence for Synthesis of a Partly Complete Skin Organ
Skin is a complex organ and it is futile to attempt identifying it with the result of
a single biochemical or morphological test. The identification problem in skin re-
generation amounts to use of a large number of structural characteristics in order to
differentiate between the newly synthesized organ, on one hand, and on the other,
well-known standards: normal skin, preferably sampled from a location adjacent to
that of the newly synthesized organ or contralateral to it; and scar, also synthesized
adjacent preferably to the newly synthesized organ.
The most complete morphological and functional comparison of normal skin,
scar, and regenerated skin is available in studies where dermis-free defects in the
guinea pig or the porcine model were grafted with the keratinocyte-seeded DRT
(Yannas et al. 1981, 1982a, b, 1984, 1989; Orgill 1983; Murphy et al. 1990; Comp-
ton et al. 1998). The data have been summarized in Table
5.2
and morphological
comparisons of the regenerated dermoepidermal junction (Fig.
5.3
), the regener-
ated dermis (Fig.
5.4
) and the subepidermal region (Fig.
5.5
) with scar have been
presented. A detailed analysis of these data follows below. (The experimental error
is given in terms of the standard deviation; the number of observations,
n
, is also
provided whenever available; the probability p that the difference between the re-
generate and normal skin, or scar, was due to random error was calculated using the
t
-test.) (Table
5.2
)
The regenerated skin resembled normal skin in several ways. The epidermis
in the regenerate was well-appointed with the cell types characteristic of normal
skin (
n
> 100 fields). The dermoepidermal junction in regenerated skin was marked
by a well-formed BM, including hemidesmosomes, a lamina lucida and a lamina
densa, anchoring fibrils, and extensive rete ridge structures (Table
5.2
). The re-
generated dermis was endowed with the microvasculature characteristic of normal
skin, including capillary loops in the papillae (
n
> 100 fields) (Fig.
5.5
). It was also
endowed with nonmyelinated nerves in the subepidermal region (
n
> 100 fields).
The thickness of regenerated skin (epidermis plus dermis; 1.20 ± 0.325 mm;
n
= 3)
was not significantly different than that of normal skin (1.325 ± 0.275 mm;
n
= 4;
p
< 0.6). The moisture permeability of normal skin (4.5 ± 0.8 g/cm/h,
n
= 4) was not
significantly different from that of regenerated skin (4.7 ± 1.9 g/cm/h,
n
= 4,
p
< 0.8).
Animals were manipulated frequently during the duration of the experiment; no
incidence of mechanical failure (avulsion or blistering) was, however, reported with
