Cultured keratinocytes as biological wound dressings

Human epidermal keratinocytes now can be grown reliably and reproducibly in vitro to form multilayered epithelium. These sheets of cultured keratinocytes have been used successfully to autograft patients with severe burns, leg ulcers and following excision of extensive congenital naevi. Whilst the technique carries the obvious advantage of huge expansion of the initial skin biopsy, thus removing the need for painful and slow healing donor sites, problems have been encountered. The take rate has been lower than with conventional split skin grafts. The take rate can be increased by the provision of a dermis. This may be achieved by providing an allodermis or by the use of a highly meshed autologous split skin graft. The wound is then covered with autologous cultured keratinocyte grafts. Manufactured dermis has been under investigation for some years and animal work suggests this may be an alternative approach. There is a delay of 2 to 3 weeks for culture of the autologous sheets of keratinocytes. This has led to the use of allogeneic grafts in a number of patients. The long term survival of these grafts has been attributed to the loss of antigen presenting cells during tissue culture. However some grafts have been rejected. Studies currently in progress may help resolve these anomalies. Whilst a number of problems remain to be solved the technique of cultured keratinocyte grafting takes wound care into an exciting new era. Skin banks may now become more than a surgeon's dream.