Researchers have succeeded in tissue engineering fully functional and complete skin patches from stem cells: the scientists recreated "a whole epidermis from human embryonic stem cells. The goal is to one day be able to propose this unlimited resource of cells as an alternative treatment in particular for victims of third degree burns and patients with genetic diseases affecting the skin. ... Human embryonic stem cells (hES) have two fundamental characteristics: a capacity for unlimited proliferation and pluripotency i.e. the capacity to differentiate into all the cell types in the human body. The first objective of the team was to obtain skin stem cells (keratinocytes) similar to those naturally present in the human epidermis from hES cells. Keratinocytes, permit the constant renewal of the skin. Once this stage was achieved, the second objective of the researchers consisted in finalising strategies to isolate keratinocyte stem cells in order to test their capacity to reconstitute a functional epidermis firstly in vitro -- then in vivo. ... Twelve weeks after transplantation, the mice presented localized areas of completely normal and functional adult human epidermis containing all the skin cell types."