By: Shelagh McNally for Wounds1
Being badly burned is one of the most terrifying and difficult injuries to recover from, with the scars remaining for a lifetime. But a new technology is providing hope for burn victims.
| Facts on Skin:|
- The skin is the largest organ.
- Skin regulates body temperature.
- Epidermis is the top layer with coating of protective cells called keratinocytes.
- Dermis is the bottom layer with fibroblasts that produce collagen..
- Blood vessels, nerves, hair follicles, oil and sweat glands are also found in the dermis.
- A first-degree burn is limited to the epidermis.
- A second-degree burn destroys the epidermis layer and is referred to as a partial thickness burn. Some require skin grafts.
- Third-degree burns, known as full thickness burns, destroy all the epidermal and dermal skin layers. Skin grafts are always needed.
- The biggest dangers with burns are infection through the exposed skin, loss of fluid and swelling.
Each year more than one million people suffer some kind of burn with just 45,000 needing to be hospitalized. Severely burned patients, usually with third-degree burns must be moved to a special burn care facility where the slow and painful healing process can begin. In the past there have been methods of treatments: Skin grafts (autografts) and using biological skin coverings. Autografts involve taking a thin layer of healthy skin and transplanting it onto the burned area. This type of treatment is usually quite successful, unless the patient has more than 50 percent of their body burned. Then there isn’t enough skin to perform an autograft. When this happens biological skin is used, usually from a human cadaver or from an animal, like a pig, whose skin is similar. The skin is placed over the burn to protect it from infection, prevent fluid loss and allow the skin to grow back. But the body’s immune system usually rejects the biological skin requiring even more surgery to re-attach new skin.
In 1987, permanent skin replacements were introduced that used skin grown from a patient’s own cell minimizing the risk of rejection. To create the new skin, cells are placed in a special culture inside a flask and given nutrients in order to grow into sheets about the size of a playing card. The patches are placed on a surgical dressing material and transplanted onto the patient and gradually bonds to the body, much like an autograft. It takes just over two weeks to grow the skin. Although many burn treatment centers now use this method, there are still drawbacks. It is very expensive and often the grafts do not take strongly leaving the area fragile for months afterwards.
In the late 1990s researchers began looking at cellular wound dressings as an alternative. Although known as artificial skin, these temporary dressings don’t really function like skin since they lack essential components. Our skin is made up of two layers. The epidermis is the thin top layer made up of a tough protective coating of dead cells called keratinocytes protecting the live keratinocytes underneath that are constantly replenishing. Inside the epidermis are the melanocytes that give color and Langerhans’ cells that fight infection. The dermis is the lower layer of skin made up of cells called fibroblasts that produce collagen, the building block of skin. The blood vessels, nerves, hair follicles, and oil and sweat glands are also found in the dermis. What cellular wound dressings try to do is simulate these two layers.
Some temporary skin replacements like Biobrane use a knitted nylon mesh bonded to a thin silicone membrane that acts as a barrier to infection. It also allows water-vapor transmissions of the wounds, which reduces the need to change dressings. As the burn wound heals, Biobrane is trimmed away from the site. The product TransCyte takes this method a step further by using a nylon mesh that has a polymer membrane filled newborn human fibroblast. Since the membrane is biocompatible there is little rejection and it’s also semi-permeable, allowing for the skin to breathe. After approximately seven days, TransCyte can be removed from healed wound sites by trimming or peeling.
Most researchers don’t fully understand why it’s effective but the results are quite dramatic. Healing time is much more rapid and scarring is dramatically reduced. For more information on the treatment of burns with artificial skin,