Skin is the largest organ of the body and is necessary for survival, since it performs many functions such as providing a physical barrier to the external environment, sensation, retention of normal hydration and thermal regulation. Significant skin loss is associated with high mortality and morbidity in the acute phase, and with physically and cosmetically drastic scarring in the long term. There are a number of tissue-engineered products in the clinic that are used as skin substitutes to promote healing of traumatic burn and diabetic wounds, producing results that satisfy the barrier function of the skin. The current tissue engineered skin although constitutes one of the most advanced tissue constructs, yet it lacks several important functions including those provided by the appendages such as the hair follicles, sebaceous and sweat glands. Dermal skin substitutes have been developed to promote regeneration of the dermis and although the incorporation of growth factors to accelerate healing has also been explored, none of them have addressed the issue of regenerating the hair follicles, sebaceous or sweat glands and their important function.
The next generation tissue engineered products should take into consideration the regeneration of its appendages taking cues from developmental biology and stem cell engineering. Although the complexity of skin may be difficult to recapitulate entirely, new or improved functions can be provided by genetic modification of the cells that make up the tissues. Gene-enhanced skin substitutes will have great potential as cell-based devices to deliver therapeutics locally or systemically and will also be employed as biological models to understand tissue development or disease progression in a realistic three-dimensional context.
Hair Transplantation and Therapy