Amniotic Membrane: Does It Have Promise For Diabetic Foot Ulcers?
Technological advances have occurred in preserving the amniotic tissue membrane along with its growth factors for use in wound healing. The amniotic tissue allograft is biologically active but does not have living cells. Its biologic activity comes from the effect of the growth factors in the graft on the host cells after implantation. The human amniotic membrane comprises the innermost layer of the placenta, which is composed of epithelial cells and connective tissue matrix of collagen and fibroblasts. Collagen types IV, V and VII make up the extracellular matrix and are substrates that are important for the integrity of the membrane and ingrowth of cells. The membrane also includes proteins such as fibronectin, proteoglycans, glycosaminoglycans and laminins.7 All of these are components of the extracelluar matrix scaffold, which aids in the organization of the body’s wound healing process.
Epidermal growth factor, transforming growth factor, fibroblast growth factor, and platelet-derived growth factors make up the biomolecules in the amniotic membrane. Applying these growth factors to wounds can accelerate healing by stimulating angiogenesis and granulation tissue formation, and enhancing epithelialization.8
Manufacturers supply human amniotic grafts dehydrated at room temperature or frozen.
What You Should Know About The Healing Properties Of Amniotic Membrane Allografts
The dehydrated amniotic/chorionic membrane allograft has both matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). The balance in activity of biomolecules and MMPs by TIMPs is a key component to the wound healing process.9 The amniotic membrane allograft has both MMPs and TIMPs, which potentially enable this regulation.
This natural human tissue scaffold acts as a medium that enables cell proliferation and differentiation. It not only promotes and enhances wound healing, but also reduces inflammation and scar tissue formation. The human derived amniotic allograft is non-immunogenic and has low antigenicity.
Only a few older reports highlight the use of amniotic membranes in foot and wound surgery.10,11 A recent but not yet published randomized controlled study compared standard therapy to the use of one of the human amniotic membranes (EpiFix, MiMedx) in chronic diabetic foot ulcers.12 Patients had weekly wound care and physicians applied dehydrated amniotic/chorionic membrane every two weeks until the wound healed. There was a healing rate of 92 percent while standard treatment only healed 8 percent over a short period of six weeks.
Chronic diabetic foot ulcers display, among many things, a decreased production of growth factors within the wound. Oftentimes, biological cell therapy is what is needed to jump-start a stalled ulcer. The dehydrated amniotic membrane allograft by MiMedx provides these growth factors that a chronic diabetic foot ulcer lacks to activate the natural wound healing process. This product is entirely derived from human tissue and has few contraindications. We have mainly discussed the product’s use in treating chronic diabetic foot ulcers but one can also use the amniotic membrane in a wide range of wounds that include surgical wounds, pressure ulcers, venous and arterial ulcers.
Dr. Shum is a third-year resident at Cedars-Sinai Medical Center in Los Angeles.
Dr. Rogers is the Co-Director of the Amputation Prevention Center at Valley Presbyterian Hospital in Los Angeles.