Skin is the body’s largest organ and it is vital for our survival. It acts as a barrier to mechanical stresses, exogenous substances, and pathogens. When our skin is damaged we lose proteins and water as well as become vulnerable to bacteria.
The repair of skin injury and defects has concerned physicians for many years. Over the last 20 years, wound care practices have advanced significantly allowing for innovative skin substitutes like Bio-engineered skin. Skin substitutes help reduce pain, close wounds, and eliminate the necessity for surgical skin grafting. These substitutes can also be used for burns, diabetic wounds, surgical wounds that won’t heal, chronic wounds, and venous leg ulcers.
History of Wound Care
Documented history dates back to the 15th century BC in Egypt where doctors wrote about herbal wound treatments and procedures, including xenografts or grafts using skin from other species. Allografts were first used in 1503 and consisted of cadaver skin. Skin grafts taken from the patient themselves for use on their wounds is called autologous grafting and was first attempted in 1871. After that, cell seeding, or epithelial grafting was used by scraping off a superficial layer of healthy skin. The cells were then transplanted directly onto the wound.
Now, xenografts and allografts can be used temporarily for skin replacements. However, there are severe limitations such as immune rejection with grafts from human donors who differ genetically from the patient. These grafts may also be slow healing, painful, may scar, and result in an infection. Ideally, autologous grafts are the best for covering wounds, but there may not be enough skin to harvest, especially with extensive burns
Bio-engineered skin was developed because of the vital need to find a medical solution to cover advanced wounds on patients that did not have enough of their own skin to harvest for skin grafting. Skin substitutes are also known as dermal replacements and tissue-based products. They help when traditional methods have failed. Bio-engineered skin is used on life-threating, third-degree and second-degree burns as well as the wounds listed above.
These skin substitutes are made of two layers; an epidermal and a dermal layer that are seeded onto an acellular matrix that forms the biological skin alternative. Growth factors and proteins are applied to the tissue so that it will grow and reproduce.
Bio-engineered tissue is grown from allogeneic sources (sources that aren’t from the patient) and the patient’s cells. Neonatal foreskin is a common source because its readily available form babies getting circumcised, grows rapidly, has an elevated amount of epidermal keratinocyte cells, and allergic reactions rarely happen.
Essentially, bio-engineered skin functions as the dermis or epidermis until the skin barrier on the victim repairs itself. It may also remain in place until a skin graft is performed. This tissue also helps wounds heal quickly because living cells re-establish the general conditions that the skin needs for repair. Those conditions include structural support, a wet wound environment, cytokines, and growth factors.
Five Classifications of Bio-engineered Skin Substitutes
- Composite matrices originating from porcine or bovine collagen, fibroblasts, human keratinocytes.
- Epithelial autografts that are cultured.
- Acellular matrices that come from bovine or porcine collagen.
- Allografts of human skin made from cadaver tissue that’s donated.
- Allogenic matrices originating from neonatal fibroblasts.
Some substitutes have regenerative properties such as allografts generated from umbilical cord and amniotic membrane. This bio-engineered skin stimulates healing and controls inflammation.
One 2016 study of diabetic foot ulcers illustrated that allograft applications had an 87.5 percent healing rate. Allografts made from umbilical cord and amniotic fluid were found as an effective treatment for complicated foot ulcers resulting from diabetes complications.
Features of Bio-engineered Skin
- Does not allow access to bacteria.
- There is no systematic or local toxicity.
- Adheres well to the surface of the wound.
- The transmission of water vapor that the bio-engineered skin allows is close to that of healthy skin.
- The structure of the inner surface allows the production or cell migration of brand-new tissue.
- The shelf-life is indefinite.
- It’s biodegradable.
- Since its non-antigenic, there will be no risk of the host rejecting it.
- It’s very flexible, so it adheres to a variety of wound surfaces.
- Easy to store.
Bio-engineered skin is not as painful as skin grafting and has few complications. It’s always available in all quantities and can be put on in the office. Bio-engineered tissue is a viable, innovative option for advanced wound care.