Skin wound healing is a sophisticated and tightly regulated biological process involving intricate interactions among various cell types, mediators, and signaling pathways[20]. The spontaneous wound healing process encompasses four stages, which may overlap or occur sequentially: (1) formation of a dynamic equilibrium of blood platelet embolism; (2) acute inflammatory stage; (3) cell migration and proliferation, encompassing extracellular matrix (ECM) formation and angiogenesis; (4) remodeling[21]. These stages are orchestrated by a myriad of cells, cytokines, and growth factors[22].Chronic wounds present challenges in healing due to factors such as bacterial infection, retention of necrotic tissue, compromised blood circulation, inadequate growth factor availability, and disruption or abnormal apoptosis of the extracellular matrix[23]. These factors contribute to a significant increase in inflammatory cells and inflammatory mediators during the acute inflammatory phase, along with excessive secretion of matrix metalloproteinases (MMPs), which degrade the extracellular matrix[24]. Glycation of the ECM during cell migration, proliferation, and remodeling results in instability, reducing the content of type I collagen fibers, proteoglycans, and other components of the loose matrix. This inhibits cell proliferation and migration, as well as the formation of vascular granulation tissue, thereby disrupting the normal wound healing process and leading to prolonged and challenging wound healing [25].
PRP is a plasma concentrate obtained from whole blood after centrifugation, comprising a variety of cell components, notably platelets in concentrations exceeding physiological levels[26]. Easily obtained through a straightforward centrifugation process, PRP represents a safe, simple, and cost-effective product [27]. Although the precise molecular mechanisms underlying PRP's promotion of wound healing remain incompletely understood, literature reports suggest several potential pathways through which PRP may enhance wound healing, either individually or in combination. Firstly, PRP is abundant in multiple growth factors, such as PDGF, TGF-β1,bFGF, and VEGF, among others[28][29][30]. These growth factors can collectively stimulate the growth of endothelial and epithelial cells, regulate their functions, and accelerate epithelial repair, angiogenesis, and granulation tissue formation. Secondly, PRP is implicated in the reduction of interleukin 17A (IL-17A) and interleukin 1β (IL-1β), thus modulating the inflammatory response in wounds. This modulation promotes vascular contraction and reconstruction, enhances wound epidermal growth, and stimulates endothelial cell proliferation, thereby potentially improving chronic wound healing and increasing local blood circulation[31][32][33].Thirdly, PRP can stimulate the production of type I collagen and matrix metalloproteinase I, inducing the formation of blood vessels and extracellular matrix, as well as the proliferation and migration of cells. This activity contributes to the structural remodeling of the wound, facilitating the healing process of chronic refractory wounds[34]. Lastly, PRP exhibits antibacterial activity against pathogens such as Staphylococcus aureus and Escherichia coli, thereby potentially improving wound infection[35].
Meta-analyses on the efficacy of autologous PRP in treating diabetic foot ulcers have demonstrated significant increases in healing rates, reduced healing times, and decreased amputation rates[36]. The 2020 China expert consensus on concentrated platelet products in wound repair also highlighted that concentrated platelet products are safe for chronic wounds, effectively promoting granulation tissue growth and re-epithelialization. These products surpass conventional wound treatments and can be used multiple times [37]. However, due to the lack of standardized methods for autologous PRP preparation, variations in preparation techniques and operator expertise result in differing platelet concentrations, leading to variable treatment outcomes. Additionally, the proportion of individuals over 65 years old is increasing year by year[38]. Many of these elderly individuals suffer from conditions such as diabetes, cardiovascular and cerebrovascular diseases, kidney diseases, and mobility impairments. They are often nutritionally deficient, presenting with moderate to severe anemia and hypoproteinemia, which can compromise platelet function and reduce platelet counts. Platelet counts in individuals over 70 years old are typically about 10% lower than in younger individuals[39]. Andia[40]also noted that the efficacy of autologous PRP injection treatment decreases with age in the context of osteoarthritis. Furthermore, each PRP preparation involves extracting tens to hundreds of milliliters of whole blood from the patient, potentially increasing their physical burden and exacerbating the underlying condition. Therefore, for patients unable to use autologous PRP due to these limitations, allogeneic PRP may be a viable alternative. Compared to autologous PRP, allogeneic PRP has broader sourcing options and easier collection methods. It can be derived from the whole blood of healthy individuals or blood banks, facilitating the extraction of an ample quantity of platelets with robust biological functionality through meticulous screening processes. Additionally, animal experiments suggest that PRP exhibits low immunogenicity[41], providing a theoretical basis for the use of allogeneic PRP.
This study found that the use of allogeneic PRP in the treatment of chronic refractory wounds is superior to conventional treatment methods without al-PRP. It significantly increases the healing rate, total efficacy rate, and wound shrinkage rate in patients with chronic refractory wounds, while also shortening the healing time. Therefore, it can effectively reduce the health risks and economic burden associated with chronic refractory wounds. Regarding the length of hospital stay, only two studies were included in the analysis, which makes the results less reliable. In all the included studies, neither the experimental group nor the control group reported significant local inflammation, allergies, or other adverse reactions.