Amniotic Membrane: Does It Have Promise For Diabetic Foot Ulcers?
The prevalence of diabetes, estimated at 14 percent in 2010, is projected to increase to 21 percent of adults in the United States by 2050.1 The Centers for Disease Control and Prevention (CDC) has projected that as many as one out of three U.S. adults could have diabetes by 2050 if current trends continue.1
The incidence of diabetic foot ulcers will likely parallel this trend and continue to rise. Those with diabetes have an annual incidence of 4 percent for the development of diabetic foot ulcers and up to 25 percent will develop a foot ulcer over their lifetime.2,3 The primary goal for these patients is to achieve quick wound closure to prevent complications such as infection and amputation.
Due to the complex nature of the diabetic foot ulcer, treatment approaches are multipronged. These include pressure reduction, ensuring adequate blood flow and tissue perfusion, eradication of infection, correcting the deformity, and good nutritional status. Proper wound debridement is also a principal component that prepares the wound bed and stimulates the healing process. With optimal wound care, a steady decrease in wound size should occur.
The percentage of reduction in foot ulcer area from baseline at four weeks is a strong predictor of healing at 12 weeks.4 Warriner and colleagues showed that a reduction in the size of foot ulcers by 90 percent at eight weeks resulted in a 2.7-fold higher incidence of healing at 12 weeks.5 If diabetic foot ulcers do not respond appropriately to standard care at four weeks, this requires re-evaluation of the current treatment plan. When wound healing stalls, one should consider adding advanced wound care therapies to the standard of care as chronic, non-healing diabetic foot ulcers are a common prequel to amputation.
There are several biologic dermal replacement grafts available for the treatment of diabetic foot ulcers. These products are either cellular or acellular. The cellular products are derived from human fibroblasts and keratinocytes. Many of the acellular products are xenografts from bovine, porcine or equine tissue.
A Closer Look At How Amniotic Membranes Work
Amniotic membrane grafts are acellular human tissues with a variety of growth factors. The role and use of amniotic membranes in treating tissue defects has received much study.
Since the early 20th century, human amniotic membrane allografts have been in widespread use in a variety of applications including burn care, dentistry, ophthalmic, ear, nose and throat, and spine surgery. This amniotic membrane allograft is most widely used in the field of ophthalmologic surgery, dating back to De Roth in 1940.6 More recently, research in early studies has shown human amniotic membrane allografts to be effective in healing diabetic foot ulcers.7 Amniotic membranes have biologically active cell products and growth factors, functioning as an extracellular collagen matrix that promotes cellular migration.
There are two layers of the placental membrane, the amnion (in contact with the amniotic fluid and fetus) and the chorion (in contact with the maternal side of the placenta). Both layers are non-immunogenic and a combination of the chorion with the amnion contains more growth factors than the amnion alone. The combination is supplied as dehydrated human amnion/chorion membrane allograft and it can treat a variety of soft tissue defects, including chronic diabetic foot ulcers.