Platelet Rich Plasma and Diabetic Foot Ulcer

The term "chronic wound" was first used in literature in the 1950s to refer to wounds that were difficult to heal or did not follow a normal healing process. However, the term has met criticism for its uncertainty regarding the duration of chronicity. Martin \& Nunan, 2015, defined a "chronic wound" as a barrier defect that has not healed in 3 months, and Leaper \& Durani, 2008, defined it as a wound that lacks a 20-40% reduction in its size after 2-4 weeks of optimal treatment or when there is no complete healing after 6 weeks. Recent reviews have highlighted the lack of consensus regarding the definition of a "chronic wound" and the need for further researches in this area. Diabetic foot ulcer is a major complication of diabetes mellitus and is the major component of diabetic foot syndrome. This medical condition affects 15% of all patients with diabetes mellitus. Alvarsson et al. in 2012 reported that up to 88% of all lower leg amputations were related to diabetic foot ulcers. The impact of chronic wounds on the health and quality of patients' life and their families should not be underestimated. Patients with chronic wounds may experience chronic pain, loss of function and mobility, depression, and anxiety, increased social stress and isolation, prolonged hospitalization, increased financial burden, and increased morbidity and mortality. Growth factors (GFs) play an essential role in the process of wound healing and tissue regeneration. Each GF has more than one effect on the healing process and acts by binding to specific cell membrane receptors on the target cells. Growth factors' effects include promoting chemotaxis, inducing cell migration and proliferation, and stimulate cells to upregulate protein production. These growth factors not only regulate cell migration and proliferation but also promote angiogenesis and remodel the extracellular matrix, creating an ideal environment that favors the cutaneous wound healing process. Over the last decades, the use of emerging cellular therapies, such as platelet-rich plasma (PRP), has more attention in a variety of diseases and settings for its potential use in the regenerative medicine as a therapeutic agent and can have an adjunctive role in a standardized, quality treatment plan. PRP is defined as plasma containing above-baseline concentrations of platelets, which is from 140 000-400 000/μl. PRP is isolated through the centrifugation of whole blood. Simply, its actions are based on the infusion of elevated platelets, thereby theoretically enhancing the biological healing capacity and tissue generation in the wound bed. Enzyme-linked immunosorbent assay studies of PRP have quantified the presence of increases in GFs such as transforming GF β, epidermal GF, and platelet-derived GF. Through degranulation of the alpha granules in platelets, PRP can secrete various GFs, which have been documented to initiate the wound healing process