Spraying on Skin Cells to Heal Burns

Traditionally, treatment for severe second-degree burns consists of adding insult to injury: cutting a swath of skin from another site on the same patient in order to graft it over the burn. The process works, but causes more pain for the burn victim and doubles the area in need of healing. Now a relatively new technology has the potential to heal burns in a way that's much less invasive than skin grafts. With just a small skin biopsy and a ready-made kit, surgeons can create a suspension of the skin's basal cells--the stem cells of the epidermis--and spray the solution directly onto the burn with results comparable to those from skin grafts.

The cell spray is intended to treat severe second-degree burns, in which the top two layers of skin are damaged but the subcutaneous tissue is left intact. Third-degree burns, which are more severe, still require a skin graft. The spray, already approved for use in some countries, has garnered interest from the United States Army, whose Armed Forces Institute of Regenerative Medicine is funding a trial, slated to begin before the end of this year, of more than 100 patients.

The technology, developed by Australian surgeon Fiona Wood, relies on cells, such as skin progenitor cells and the color-imparting melanocytes, that are most concentrated at the junction between the skin's top two layers. With a small step-by-step kit dubbed ReCell, surgeons can harvest, process and apply these cells to treat a burn as large as 10.5 square feet. The kit, marketed by Avita Medical, a United Kingdom-based regenerative-medicine company, is a tiny, self-contained lab about the size and shape of a large sunglasses case.

After removing a small swatch of skin near the burn site (the closer the biopsy, the better for precise matching of color and texture), the surgeon places it in the kit's tiny incubator along with an enzyme solution. The enzyme loosens the critical cells at the skin's dermal-epidermal junction, and the surgeon harvests them by scraping them off the epidermal and dermal layers and suspending them in solution. The resulting mixture is then sprayed onto the wound, repopulating the burn site with basal cells from the biopsy site.

"Currently, treating any burn that requires a skin graft is the same technology we were routinely using 30 years ago," says James Holmes, a surgeon and the medical director of the Burn Center at Wake Forest University Baptist Medical Center. Current practice with larger burns requires grafts from donor skin that are anywhere from one-quarter to the complete size of the burn area. ReCell requires only as much as four square centimeters. "This allows you to take a very small skin biopsy and process it at the table there in the operating room using a fully prepackaged device," Holmes says. "You're able to cover an area that's 80 times the size of your biopsy."

Holmes is the lead investigator on an upcoming multicenter trial that will compare skin grafts and ReCell. Patients in the trial will act as their own controls: If a burn victim has a second-degree burn severe enough for surgeons to deem treatable by skin graft, half of the burn will be treated that way, while the other half will be treated with the cell spray.