Diabetic Foot Ulcer

Diabetic foot ulcer is a major complication of diabetes mellitus, and probably the major component of the diabetic foot. It occurs in 15% of all patients with diabetes and precedes 84% of all lower leg amputations. Major increase in mortality among diabetic patients, observed over the past 20 years is considered to be due to the development of macro and micro vascular complications, including failure of the wound healing process. Wound healing is a ‘make-up’ phenomenon for the portion of tissue that gets destroyed in any open or closed injury to the skin. Being a natural phenomenon, wound healing is usually taken care of by the body’s innate mechanism of action that works reliably most of the time. Key feature of wound healing is stepwise repair of lost extracellular matrix (ECM) that forms largest component of dermal skin layer. Therefore controlled and accurate rebuilding becomes essential to avoid under or over healing that may lead to various abnormalities. But in some cases, certain disorders or physiological insult disturbs wound healing process that otherwise goes very smoothly in an orderly manner. Diabetes mellitus is one such metabolic disorder that impedes normal steps of wound healing process. Many histopathological studies show prolonged inflammatory phase in diabetic wounds, which causes delay in the formation of mature granulation tissue and a parallel reduction in wound tensile strength.

Non-healing chronic diabetic ulcers are often treated with extracellular matrix replacement therapy. So far, it is a common trend in diabetic foot care domain to use advanced moist wound therapy, bio-engineered tissue or skin substitute, growth factors and negative pressure wound therapy. No therapy is completely perfect as each type suffers from its own disadvantages. Moist wound therapy is known to promote fibroblast and keratinocyte proliferation and migration, collagen synthesis, early angiogenesis and wound contraction. At present, there are various categories of moist dressings available such as adhesive backing film, silicone coated foam, hydrogels, hydrocolloids etc. Unfortunately, all moist dressings cause fluid retention; most of them require secondary dressing and hence are not the best choice for exudative wounds. To address the physiological deficiencies underlying diabetic ulcer, various tissue engineering technologies have come up with cellular as well as acellular skin replacement products.