Use of keratinocytes in combination with a dermal replacement to treat skin loss - Biomaterials for Treating Skin Loss - page 206

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Use of keratinocytes in combination with a
dermal replacement to treat skin loss
G. PIETRAMAGGIORI
Brigham and Women's Hospital, USA
Abstract: The process of induced regeneration of the adult skin is tradition-
ally based on a sequential two-step technique in which an acellular dermal
scaffold and a thin skin graft are grafted in the wound bed in two sequential
surgical procedures. More recently, it has been shown that autologous
keratinocytes can be seeded directly into the dermal scaffolds resulting in
contemporary dermal and epidermal regeneration upon grafting. This one-
step procedure reduces the morbidity of the patients and the hospital costs,
while allowing for improved skin regeneration, compared to the traditional
two steps.
Key words: autologous keratinocytes, one-step skin regeneration, cell
seeding, neovascularization.
13.1 Simultaneous substitution of dermis and
epidermis: from two-step to one-step skin
replacement
Skin is an organ in adults that has extensive evidence of induced regeneration
(Yannas, 2005a). The process of induced regeneration in adult skin is based on a
sequential two-step technique (Murphy et al ., 1990; Orgill et al ., 1999). In the first
step, after initial excision, full-thickness wounds are grafted with acellular dermal
substitutes covered by a silicone sheet which functions as a temporary pseudo-
epidermis. During the second step, generally 2-3 weeks later, the silicone layer is
replaced by a thin skin graft, which stably closes the wound (Murphy et al ., 1990;
Orgill et al ., 1999). Despite excellent results in a wide range of patient populations
using the two-stage operation, during the waiting period scaffolds are highly
susceptible to infection mainly owing to slow neovascularization (Butler et al .,
1999). In addition, the second step adds morbidity, requiring a significant donor
site in many patients who have limited uninjured areas to choose from (Butler et
al ., 1998) and often inducing hypertrophic scarring in children (Compton et al .,
1998).
Recent evidence has demonstrated that the addition of keratinocytes to the
construct significantly improves the performance of acellular scaffolds, allowing
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