A study in this week’s edition of The Lancet shows that it is possible to use human embryonic stem-cells (hESCs) to produce temporary skin substitutes for patients awaiting skin grafts after, for example, serious burn injuries. The Article is written by Dr Christine Baldeschi, INSERM and Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, Evry Cedex, France, and colleagues.

For more than 20 years, patients with serious burns have benefited from cell therapy to help them recover from their injuries. In this therapy, the patient’s own skin cells (keratinocytes) are taken, and more are grown in the laboratory and used to replace the damaged skin. But the major drawback of this is the 3-week period needed to grow enough cells, which puts the patients at risk of dehydration and infection. Decellularised skin from deceased persons can be used to cover wounds during this period, but availability is limited and the tissue is often rejected by the host. To overcome the problem of accessibility, inert synthetic and biosynthetic matrices have been actively searched for and developed. Up to now, however, these substitutes have not replaced skin from deceased persons in large burns since they increase the risks of rapid graft rejection and disease transmission—because they contain bovine collagen and adult allogenic skin cells.

In this study, the hESC were seeded on feeder cells using a pharmacological treatment over 40 days. This treatment drives hESCs towards becoming keratinocytes linage by following biological steps that lead to epidermis formation during embryonic development. The team were able to generate a population of cells that showed the characteristics of keratinocytes. Once placed on an artificial matrix, the cells were able to form a layer of skin. Just 12 weeks after grafting onto five mice, the skin layer derived from the hESCs had a structure consistent with human skin.

The authors say: “We have shown that keratinocytes can be derived from hESCs... Growing human epidermis from hESCs could have clinical relevance as an unlimited resource for temporary skin replacement in patients with large burns awaiting autologous grafts.”

They add that future work should look at whether or not this technology could extend the period needed to grow enough cells for a permanent graft, or if keratinocyte hESCs could be used for a permanent graft in situations where a permanent graft using the patients’ own keratinocytes is not possible.

In an accompanying Comment, Dr Holger Schlüter and Dr Pritinder Kaur, Epithelial Stem Cell Biology Laboratory, Peter MacCallum Cancer Centre, Melbourne, Australia, say: “This report takes research into regenerative skin stem cells to the next level...This finding suggests that keratinocyte allografts derived from hESC keratinocytes could be transplanted onto burnt patients awaiting skin grafts with a reduced risk of rejection.”