Every year in the United States, 1.1 million burn injuries require medical attention. Approximately 50,000 of these require hospitalization, 20,000 burn injuries are to more than 25 percent of total body surface area, and 4,500 people die. Another 10,000 die every year from burn-related infections.1
First and second-degree (partial thickness) burns have the ability to heal and restore relatively normal skin. Full thickness, or third degree burns destroy both the epidermis and the dermis, and the skin cannot regenerate.
The scarring that occurs after a burn has a significant impact on quality of life. Burn scars are both aesthetically and functionally challenging causing itching, lack of movement, pain, diminished sensory perception and contracture or shortening of the scar over time, which often requires follow-on surgeries. When the dermis is destroyed, the scars do not regrow hair, nerves or sweat glands, providing additional challenges to body temperature control.
While many methods of treatment and coverage for full thickness burns exist, none provides fully functional skin repair or replacement. Ideal skin replacement products would:
Provide a physical barrier
Be flexible and strong
Provoke angiogenesis (restoration of blood supply)
Not be rejected
Undergo controlled degradation
Be easily applied to the wound
Promote formation of skin appendages (sweat glands, hair follicles, sensory tissue)
Be readily available and affordable
None of the currently available skin substitutes satisfies these criteria. Substitutes composed of autologous cells (cells derived from the patient’s own skin) will not be rejected, but take up to six weeks to prepare for grafting, and require the formation of a second wound site from which the healthy cells are harvested. Skin substitutes comprised of human cadaver skin or animal products present problems with rejection and possible disease transmission. Completely synthetic options provide only a biological dressing, and other skin substitutes require multiple applications over time, driving up costs and diminishing effectiveness.
The need is for a tissue-engineered skin for skin replacement. Skin made from cells and extracellular matrices (ECM) could provide the best skin replacement because it would enable healing, cell differentiation into sweat glands and hair follicles (or these specialized cells could be incorporated into the product), and strength and manageability. However, the use of cells from another person introduces the problem of tissue rejection, leading to failure of the graft.
Research is required to overcome rejection issues, either using cells that are genetically unrecognizable to the patient’s immune system, or providing some other local prevention of detection method such as immunosuppressive strategies. The ideal skin replacement would also be packaged suitably for extreme environments to make it useful for military field hospitals.
This extremely difficult and challenging undertaking can be addressed with funding directed to this important area of research. NTI seeks to distribute funding to researchers with products ready for clinical trials in the near-term, with the expectation that rapid progress can be made to urgently help burn patients.
1CDC (2006) Mass Casualties: Burns. http://www.bt.cdc.gov/masscasualties/burns.asp