Advances in tissue-engineered skin substitutes
01/02/11 | Complex wounds, Skin integrity | Damanhuri M, Boyle J, Enoch,S
Large skin defects resulting from burns, trauma, congenital giant nevi, and disease can lead to skin necrosis and represent a challenge to achieving skin coverage. This article summarises the development of tissue-engineered skin substitutes, identifies key clinical landmarks, reviews some critical aspects of cell and skin biology and highlights future developments that may foster progress in engineered skin.
The emphasis in managing burns and complex non-healing wounds has shifted from merely reducing morbidity and achieving satisfactory survival to ultimately improving the long-term prognosis, function and aesthesis of healed wounds. Large skin defects resulting from burns, trauma, congenital giant nevi and disease can lead to skin necrosis and represent a challenging clinical problem that necessitates a novel approach to achieving skin coverage [1,2].
The primary problem in this type of wound is usually a shortage of autologous skin. For example, in a patient with a 70% total body surface area (TBSA) burn, the remaining 30% of normal skin is insufficient to provide coverage . The secondary problem is scarring, which often results at both the recipient and donor sites from the 'gold standard' of using an autologous split thickness skin graft (STSG) (epidermis and part dermis). In certain instances, this can result in hypertrophic or keloid scars that can be further disabling and disfiguring [4,5].
Although full-thickness skin grafting (FTSG) (all of dermis) leads to less scarring, it can only be performed if the injured area is approximately 1% of the TBSA. Thus, its widespread use is limited by donor site availability.
Theoretically, both of these issues could be reduced or even eliminated if it were possible to culture a skin substitute that encompassed both epidermis and dermis. In deep wounds, an optimal skin substitute would provide immediate replacement of both these layers with permanent wound coverage . The features of an 'ideal' skin substitute are shown in [Box 1].
Unfortunately, there are currently no engineered skin substitutes that can completely simulate the complexity of human skin, either in form or function. However, with advances in tissue engineering and biotechnology, there are several skin substitutes, both being used and in development [Fig 1], that can be used for replacement or reconstruction of one or both layers of the skin.