Wounds and ulcers on mice can be healed by reprogramming cells within the wound into surface skin cells to seal up the injury, reports a study published online this week in Nature.

A key step in healing wounds is the migration of keratinocytes (the primary cells of the outmost layer of skin) from the surrounding tissue into the wound to seal up the damage. For larger wounds, however, this process is inefficient and becomes more so with age. As the healing capacity of the skin diminishes, minor injuries develop more easily into non-healing wounds and painful, sometimes life-threatening ulcers. With ageing populations, the incidence of chronic ulcers is also on the rise - bringing with it a demand for simpler wound treatments that are more effective than the skin transplants and costly prosthetic grafts presently available.

Juan Carlos Izpisua Belmonte and colleagues use cellular-reprogramming technology to transform cells from the connective tissue of wounds into progenitors of keratinocyte cells that seal the injury, replacing the need for cell migration. They identify four proteins that are needed to program the cells into skin, and deliver them via viruses directly onto non-healing ulcers on the back of mice. The authors find that the reprogramming successfully healed over the injured skin. Although further improvements and safety testing are needed, the researchers suggest that the technique could be applied to human skin injuries and possibly other damaged tissues and organs.