A Closer Look At Topical Therapies In Wound Care
- Volume 26 - Issue 8 - August 2013
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Given the increasing numbers of diabetic wounds among the populace and the complex environment of wounds, it is crucial to have a grasp of effective topical treatment options that can facilitate healing. These authors discuss factors that affect wound healing as well as treatment options ranging from hydrogel dressings and calcium alginate to split thickness skin grafts, foams and biologics.
In the year 2030, diabetes is projected to affect 4.4 percent of the population worldwide.1 It has been estimated that upward of 15 percent of those diagnosed with diabetes will develop a foot ulceration in their lifetime.2
Therefore, having an understanding of wound healing as well as a comprehensive knowledge of common topical wound care therapies is of great importance. Having this knowledge allows one to facilitate the optimal wound healing environment based upon the type of diabetic foot ulcer (DFU) that is present. Accordingly, let us review the wound healing phases, key factors that affect wound healing and lastly common topical wound care therapies clinicians may use in the treatment of DFUs.
Wound healing is a dynamic process composed of four distinct but continuous phases. These phases are rapid hemostasis, inflammation, proliferation and remodeling.3
The rapid hemostasis phase consists of vasoconstriction and fibrin clot formation. The fibrin clot releases well-known pro-inflammatory cytokines and growth factors, such as platelet-derived growth factor (PDGF), fibroblast growth factor (FGF) and epidermal growth factor (EGF). These cytokines and growth factors promote chemotaxis of neutrophils, macrophages and lymphocytes.4 As these cells are stimulated, the inflammatory phase begins.
Neutrophils are the first responders during the inflammatory phase. These cells help remove invading bacteria and cellular debris. Macrophages have a similar role but subsequently go on to a phenotypic transition that stimulates and attracts cells like fibroblasts and keratinocytes. Researchers have noted that macrophages aid in the initiation of angiogenesis.5 While their role is entirely known, lymphocytes such as t-lymphocytes also hold an important role in the inflammatory phase. They are believed to release important cytokines for cell-to-cell communication, thereby helping to defend the wound from pathogens and also assist in the process of regulating inflammation. As such, this allows the proliferative phase to peak.3-6
The proliferative phase is characterized by the migration and maturation of fibroblasts and endothelial cells. These cells are necessary for wound healing as they promote collagen formation, support capillary growth and establish the foundation for granulation tissue. Fibroblasts are also extremely important in the formation of the extracellular matrix as these cells are known to produce collagen, glycosaminoglycans and proteoglycans. The proliferative phase is quite robust but eventually ceases, leading the way to the long-term phase of remodeling.
Remodeling is the last and final phase of wound healing. During this phase, the extracellular matrix is remodeled in order to support the architecture of normal tissues. Perhaps the most obvious sign of remodeling is the physical wound contraction, which occurs with the help of myofibroblasts.6 The remodeling phase is well known to be a slow process, often lasting years.
Key Factors That Have A Negative Impact On Wound Healing
Any disruption to the aforementioned wound healing phases will lead to delayed healing or chronic wounds. Some of the most common interruptions to wound healing include ischemia, sensory neuropathy and infection.