By David H. Ahrenholz, MD
One hundred fifty years ago, a third-degree burn covering just 10% of the body was 100% lethal. The science and the treatment simply didn’t exist to replace severely burned tissue before infection took over. During and after World War II, however, skin grafting entered the fray, and by the 1980s, cultured epidermis products were introduced to the market. Suddenly, the treatment of large and severe burns became much more feasible, and today the mortality rate for these conditions is less than 5% in the developed world.
This momentum is certainly positive for burn surgeons everywhere, but the industry has almost plateaued. Split-thickness skin grafting, first used in the 1940s, is still the approved treatment for large and severe burns today, and skin substitute products, first introduced 25 years ago, are present in the operating room, though they are expensive and difficult to use. There has not been a commercially available solution that functions like an autologous skin graft, while eliminating the need for multiple harvests from a single donor site, until now.
It’s possible to engineer large quantities of a patient’s own skin—from their own cells—in less time than it takes for a single harvest site to heal. Unlike many of the synthetic or single-layer skin substitutes available today, Amarantus BioScience’s Engineered Skin Substitute (ESS) could be a game-changer for the treatment of large burns. The technology allows cultured epithelial cells to grow on a matrix that is similar to the inner layer of skin. The composite structure, the inner dermis layer with the epidermal layer, are then transplanted together.
The Way Forward
Autologous skin grafts have widely been used for the treatment of large burn cases mainly because risk of rejection is relatively low when using a patient’s own skin to replace burned tissue. But this therapy is not without its limits. When a patient has third-degree burns covering a majority of their body, surgeons are left with little choice than to harvest what living skin is left—over and over again—until the burns are covered and healed. It’s not uncommon for a treatment like this to take months or even years to complete. Patients are highly susceptible to infection, sepsis, or disease during treatment, which is why the mortality rates continue to stay unnecessarily high for this population.
Moreover, donor sites take time to heal, and the health of the skin is reduced as grafting continues. It’s a painful and vicious cycle that yields diminishing results. Imagine six, 10, or even 12 operations on the same part of the body. Skin quality is affected after each procedure, but it also takes longer to heal afterward. The process gets more painful as time goes on. Pediatric cases are even more challenging, since growing children need to continue receiving new skin grafts as their body matures—often for years after an injury.
Tissue-engineered skin substitutes can be created from a single biopsy of not more than a few square inches, and then grown in as little as a month. What patients receive is their own skin in quantities much larger than what could safely be harvested. It grows with patients, eliminating the need for ongoing surgeries. With ESS, the risk of infection and rejection are reduced, and the suffering that’s associated with burn care is diminished.
The economics are affected, too. Large and severe burn cases take months or years to complete. It’s not difficult to understand the financial benefits of fewer operations and less time in a burn center, both for patients and for hospital systems. And burn care is just the beginning. Dermatological conditions like Congenital Hairy Nevus have been treated with ESS. Cosmetic or reconstructive surgeons suddenly have an off-the-shelf solution to produce new skin for patients.
Changing the Standard of Care
ESS is finally on its way to commercialization with upcoming phase 2 US Food and Drug Administration trials and a research agreement with the US Army.
It’s time to once again reduce burn-related mortalities with a better and more humane treatment. The next standard of care for severe burns needs to be growing patients’ own skin in less time and with less pain than with skin grafting. Ultimately, a solution like ESS would improve the standard of care for patients with near-full-body burns while saving time and hospital resources, too.
David H. Ahrenholz, MD, is a retired surgeon from the Burn Center at Regions Hospital in St Paul, Minn, and the immediate past president of the American Burn Association. He can be reached at [email protected].