Efficacy and safety of autologous platelet rich plasma for the treatment of vascular ulcers in primary care: Phase III study

Platelets, Protean Cells with All-Around Functions and Multifaceted Pharmacological Applications

Platelets, traditionally known for their roles in hemostasis and coagulation, are the most prevalent blood component after erythrocytes (150,000-400,000 platelets/μL in healthy humans). However, only 10,000 platelets/μL are needed for vessel wall repair and wound healing. Increased knowledge of the platelet's role in hemostasis has led to many advances in understanding that they are crucial mediators in many other physiological processes, such as innate and adaptive immunity. Due to their multiple functions, platelet dysfunction is involved not only in thrombosis, mediating myocardial infarction, stroke, and venous thromboembolism, but also in several other disorders, such as tumors, autoimmune diseases, and neurodegenerative diseases. On the other hand, thanks to their multiple functions, nowadays platelets are therapeutic targets in different pathologies, in addition to atherothrombotic diseases; they can be used as an innovative drug delivery system, and their derivatives, such as platelet lysates and platelet extracellular vesicles (pEVs), can be useful in regenerative medicine and many other fields. The protean role of platelets, from the name of Proteus, a Greek mythological divinity who could take on different shapes or aspects, is precisely the focus of this review.

A case series of platelet rich plasma in chronic venous ulcers

INTRODUCTION

Venous ulcers are the most common type of leg wounds (80%) and the main cause is chronic venous insufficiency. Autologous platelet-rich plasma (PRP) is a potential wound healing treatment due to its great variety of growth factors. The aim of this study was to describe in a case series the results of poor-leukocyte PRP (P-PRP) or saline for the treatment of chronic non-healing ulcers of the lower extremity.

METHODS

Eight patients were treated according to the topical therapy: saline solution or P-PRP gel. All patients used double compression stocks and were assisted by a vascular practitioner for up to 12 months or until wound healing. The treatment was performed weekly with cleaning of the affected area, macroscopic evaluation (area measurement and photos) and P-PRP or saline application, and closure with Tegaderm®. Trial Registration: Retrospectively approved by Brazilian Clinical Trials, register number RBR-7zhgb3 (http://www.ensaiosclinicos.gov.br/rg/RBR-7zhgb3/).

RESULTS

All patients showed signs of wound healing with a reduction in wound size and ulcer numbers, but more evident with P-PRP application.

CONCLUSIONS

The results suggested that P-PRP presented a better result when compared to saline solution in the healing process of long clinical course chronic venous ulcers, when associated to compressive stocks and topical care.

Assessment of apheresis platelets during 5 days of storage: A National Cancer Institute, Cairo University experience

BACKGROUND

Platelet transfusion therapy is widely used to prevent hemorrhage in patients with thrombocytopenia and platelet disorders. The platelet concentrate (PC) quality is affected by increased storage time, as reflected in the decreased number of platelets, morphological changes, and impaired functions. This study aimed to analyze the impact of 5 days storage on platelets count and the expression of CD63, and Annexin V as activation markers during PC storage.

METHODS

Fifty PCs collected from single donors were tested for platelet count on days 0, 3, and 5 using a Sysmex blood counter. CD61, CD63, and Annexin V expression was analyzed by a multicolor Navios flow cytometer.

RESULTS

There was a significant decrease in platelet count during 5 days of storage. There was a direct relationship between storage time and degree of platelet activation. CD63 had almost double increased expression on day 5 than day 3. Annexin V showed significantly increased expression on day 3 with minor differences between days 3 and 5.

CONCLUSION

According to standard blood bank conditions, PC stored for 5 days showed a degree of in vitro activation as evidenced by CD63 and Annexin V expression, may lead to reduced therapeutic efficacy. Flow cytometry monitoring platelet activation in PC offers a better understanding of the changes during PC storage and may help improve platelet products.

Growth factors for treating chronic venous leg ulcers: A systematic review and meta-analysis

Chronic venous leg ulcers (VLU) are wounds that commonly occur due to venous insufficiency. Many growth factors have been introduced over the past two decades to treat VLU. This systematic review and meta-analysis evaluates the impact of growth factor treatments of VLU in comparison to control for complete wound healing, percent reduction in wound area, time to wound healing, and adverse events. A systematic review and meta-analysis of randomised trials was conducted. MEDLINE and EMBASE were searched up to December 2020. Studies were included if they compared a growth factor versus placebo or standard care in patients with VLU. From 1645 articles, 13 trials were included (n = 991). There was a significant difference between any growth factor and placebo in complete wound healing (P = 0.04). Any growth factor compared to placebo significantly increased the likelihood of percent wound reduction by 48.80% (P = <0.00001). There was no difference in overall adverse event rate. Most comparisons have low certainty of evidence according to Grading of Recommendations, Assessment, Development, and Evaluation. This meta-analysis suggests that growth factors have a beneficial effect in complete wound healing of VLU. Growth factors may also increase percent reduction in wound area. The suggestion of benefit for growth factors identified in this review is not a strong one based on the low quality of evidence.

Objective assessment of Platelet-Rich Plasma (PRP) potentiality in the treatment of Chronic leg Ulcer: RCT on 80 patients with Venous ulcer

BACKGROUND

Chronic venous leg ulcer reduces the patients' activities and their overall quality of life. Platelet-rich plasma (PRP) was previously investigated as promising less invasive management for leg ulcers.

THIS STUDY AIMS

To re-assess the efficacy and safety of PRP in the management of chronic leg ulcers due to venous factors.

PATIENTS/METHODS

RCT enrolled 80 patients who clinically presented with chronic venous leg ulcers. Forty patients were allocated randomly for the treatment with autologous platelet-rich plasma (PRP). Intradermal and subdermal injection of PRP by 27guage syringe weekly, in all edges and in the granular floor of the ulcer for 4-6 sessions. Another 40 patients managed by conventional treatment by compression and dressing for the same period were allocated as Group B. Objective assessment achieved by the percentage of reduction of the size of the ulcer area, rate of healing, incidence of recurrence, and if side effects have been reported.

RESULTS

PRP therapy showed better results and high p value significance when compared to conventional therapy.

CONCLUSION

This study shows that PRP is effective and significant in promoting the wound healing process in chronic leg venous ulcers. PRP is simple, safe, and has a short learning curve technique.

Overview of Current Advances in Extrusion Bioprinting for Skin Applications

Bioprinting technologies, which have the ability to combine various human cell phenotypes, signaling proteins, extracellular matrix components, and other scaffold-like biomaterials, are currently being exploited for the fabrication of human skin in regenerative medicine. We performed a systematic review to appraise the latest advances in 3D bioprinting for skin applications, describing the main cell phenotypes, signaling proteins, and bioinks used in extrusion platforms. To understand the current limitations of this technology for skin bioprinting, we briefly address the relevant aspects of skin biology. This field is in the early stage of development, and reported research on extrusion bioprinting for skin applications has shown moderate progress. We have identified two major trends. First, the biomimetic approach uses cell-laden natural polymers, including fibrinogen, decellularized extracellular matrix, and collagen. Second, the material engineering line of research, which is focused on the optimization of printable biomaterials that expedite the manufacturing process, mainly involves chemically functionalized polymers and reinforcement strategies through molecular blending and postprinting interventions, i.e., ionic, covalent, or light entanglement, to enhance the mechanical properties of the construct and facilitate layer-by-layer deposition. Skin constructs manufactured using the biomimetic approach have reached a higher level of complexity in biological terms, including up to five different cell phenotypes and mirroring the epidermis, dermis and hypodermis. The confluence of the two perspectives, representing interdisciplinary inputs, is required for further advancement toward the future translation of extrusion bioprinting and to meet the urgent clinical demand for skin equivalents.

Effectiveness of autologous PRP therapy in chronic nonhealing ulcer: A 2-year retrospective descriptive study

CONTEXT

Chronic nonhealing ulcer is a troublesome condition in patients especially with diabetes. Autologous PRP therapy can safely and effectively heal a chronic nonhealing ulcer in such patients.

AIMS

To study the effectiveness of autologous PRP therapy in a chronic nonhealing ulcer.

SETTINGS AND DESIGN

A retrospective descriptive study from previous case records of chronic nonhealing ulcer patients who were treated with autologous PRP therapy at a specialty orthopedic hospital from September 2017 to August 2019.

METHODS AND MATERIALS

Data on patients who presented with chronic nonhealing ulcers of >4 weeks duration who were treated with autologous PRP therapy and followed up for 20 weeks.

STATISTICAL ANALYSIS USED

Statistical Package for the Social Sciences (SPSS) version 20 was used to calculate mean. Microsoft Excel was used for preparing the chart.

RESULTS

The mean age of patients treated with autologous PRP therapy was 61.24 years, and the follow-up period was 20 weeks. The mean duration of ulcer healing following PRP therapy was 11.25 weeks, 80% of the patient showed ulcer size reduction of >75% following therapy.

CONCLUSIONS

In this retrospective descriptive study, it has demonstrated the effectiveness and safety of autologous PRP therapy in the healing of chronic nonhealing ulcers.

A prospective study comparing topic platelet-rich plasma vs. placebo on reducing superficial perioral wrinkles and restore dermal matrix

Introduction: The goal of our prospective study was to assess the efficacy of the topical Platelet-rich plasma on reducing superficial perioral wrinkles and restoring the dermal matrix. Materials and methods: 50 women with moderate to severe perioral wrinkles were treated on the perioral area by a single session of fractional CO2 laser skin resurfacing plus intradermal injection of prp. 25 patients (group 1) applied topically prp twice a day for 12 weeks as post laser treatment. 25 (group 2) applied gentamicin and betamethasone twice a day for the first 7 days and then hyaluronic acid gel for the following 12 weeks. Results: In group 1, moisture (p < 0.001), amount of collagen fiber (p < 0.001) skin elasticity (p < 0.001), PSAl (p < 0.001) and SSAl (p < 0.001) improved significantly. In group 2 all the parameters investigated improved but did not reach significant difference. Discussion: Our medical device with a plasma-like formulation is able to maintain prp active for a period of 7 days so patients are able to apply topically growth factors at home. Conclusions: Our prospective study proves that the use of topical prp reduces superficial perioral wrinkles and restore dermal matrix when used at home for 12 weeks.

Platelet-rich plasma, a powerful tool in dermatology

Platelet-rich plasma (PRP), a platelet concentrate contained in a small volume of plasma, has become a promising option in the last decade to treat different diseases related to the skin due to its high concentration of growth factors. When it is of autologous origin, it decreases the probability of suffering adverse reactions and transfusion-transmitted infections, thus it is an optimal and safe therapy for the patient. PRP has been used in the treatment of several dermatological conditions such as acne, alopecia, and skin ulcers. Its use has also extended to other skin conditions such as melasma, hyperpigmentation, and burns, where it stimulates tissue repair and regeneration. The purpose of this article is to review the management and treatment of different dermatological alterations with PRP. Although there are a variety of studies that support the use of PRP, more research is needed to standardise the protocols for obtaining, processing, and applying it as well as understanding the biological and molecular bases of its functioning.

Influence of Platelet-Rich and Platelet-Poor Plasma on Endogenous Mechanisms of Skeletal Muscle Repair/Regeneration

The morpho-functional recovery of injured skeletal muscle still represents an unmet need. None of the therapeutic options so far adopted have proved to be resolutive. A current scientific challenge remains the identification of effective strategies improving the endogenous skeletal muscle regenerative program. Indeed, skeletal muscle tissue possesses an intrinsic remarkable regenerative capacity in response to injury, mainly thanks to the activity of a population of resident muscle progenitors called satellite cells, largely influenced by the dynamic interplay established with different molecular and cellular components of the surrounding niche/microenvironment. Other myogenic non-satellite cells, residing within muscle or recruited via circulation may contribute to post-natal muscle regeneration. Unfortunately, in the case of extended damage the tissue repair may become aberrant, giving rise to a maladaptive fibrotic scar or adipose tissue infiltration, mainly due to dysregulated activity of different muscle interstitial cells. In this context, plasma preparations, including Platelet-Rich Plasma (PRP) and more recently Platelet-Poor Plasma (PPP), have shown advantages and promising therapeutic perspectives. This review focuses on the contribution of these blood-derived products on repair/regeneration of damaged skeletal muscle, paying particular attention to the potential cellular targets and molecular mechanisms through which these products may exert their beneficial effects.

Role of Topical Biological Therapies and Dressings in Healing Ischemic Wounds

Ischemic wounds are the most severe expression of critical limb ischemia (CLI), and they have been defined clinically as an end stage of peripheral arterial disease. Urgent revascularization is a fundamental part for limb salvage in patients with CLI. However, the risk of revascularization should be weighed against the likelihood of success given a patient’s life-threatening comorbidities. Once the condition of arterial insufficiency is revascularized, wound care is an important aspect to promote the wound healing process and infection control. MOIST concept for wound care is a modern systematic treatment for enhanced wound healing process. Currently, advanced biological therapies are emerging in ischemic wound therapies to restore the wound healing process and involve active biological agents to support the wound healing process. We studied and summarized the different types of available topical biological therapies and their mechanisms on the healing process including platelet-derived growth factor, epidermal growth factor, fibroblast growth factor, and vascular endothelial growth factor, platelet-rich plasma, and honey for local wound care of patient with CLI. Our review suggests that topical platelet-derived growth factor, epidermal growth factor, platelet-rich plasma, and honey are available as well as considered in the ischemic wound healing process enhancement through the MOIST concept. In conclusion, biologic wound dressing or topical agent therapy may improve the wound healing process, increase limb salvage, is inexpensive, and provides potential safety with nontoxic low-risk therapy in patients with an ischemic wound. Thus, local wound care by biological dressing should be added in adjuvant treatment for ischemic wound patients. However, further randomized studies are needed to support efficacy and long-term outcomes of these biological dressing in patients with ischemic wound.

Platelet-Rich Plasma Prevents In Vitro Transforming Growth Factor-β1-Induced Fibroblast to Myofibroblast Transition: Involvement of Vascular Endothelial Growth Factor (VEGF)-A/VEGF Receptor-1-Mediated Signaling †

The antifibrotic potential of platelet-rich plasma (PRP) is controversial. This study examined the effects of PRP on in vitro transforming growth factor (TGF)-β1-induced differentiation of fibroblasts into myofibroblasts, the main drivers of fibrosis, and the involvement of vascular endothelial growth factor (VEGF)-A in mediating PRP-induced responses. The impact of PRP alone on fibroblast differentiation was also assessed. Myofibroblastic phenotype was evaluated by confocal fluorescence microscopy and western blotting analyses of α-smooth muscle actin (sma) and type-1 collagen expression, vinculin-rich focal adhesion clustering, and stress fiber assembly. Notch-1, connexin 43, and VEGF-A expression were also analyzed by RT-PCR. PRP negatively regulated fibroblast-myofibroblast transition via VEGF-A/VEGF receptor (VEGFR)-1-mediated inhibition of TGF-β1/Smad3 signaling. Indeed TGF-β1/PRP co-treated fibroblasts showed a robust attenuation of the myofibroblastic phenotype concomitant with a decrease of Smad3 expression levels. The VEGFR-1 inhibition by KRN633 or blocking antibodies, or VEGF-A neutralization in these cells prevented the PRP-promoted effects. Moreover PRP abrogated the TGF-β1-induced reduction of VEGF-A and VEGFR-1 cell expression. The role of VEGF-A signaling in counteracting myofibroblast generation was confirmed by cell treatment with soluble VEGF-A. PRP as single treatment did not induce fibroblast myodifferentiation. This study provides new insights into cellular and molecular mechanisms underpinning PRP antifibrotic action.

Methacrylate dressing on refractory venous leg ulcers

Chronic leg ulcers can have a major impact on the quality of life of patients. These wounds can be complex and hard to heal, as several factors may affect the outcome. Underlying conditions, bacterial growth and excess moisture may prevent wounds from healing. We describe the case of a patient with known chronic venous disease, who was admitted to our hospital for several complex, irregular and infected chronic venous ulcers in his lower legs. The management was frustrating for several months, until we began to use methacrylate powder dressing for his hard-to-heal wounds.

Combined use of bone marrow-derived mesenchymal stromal cells (BM-MSCs) and platelet rich plasma (PRP) stimulates proliferation and differentiation of myoblasts in vitro: new therapeutic perspectives for skeletal muscle repair/regeneration

Satellite cell-mediated skeletal muscle repair/regeneration is compromised in cases of extended damage. Bone marrow mesenchymal stromal cells (BM-MSCs) hold promise for muscle healing but some criticisms hamper their clinical application, including the need to avoid animal serum contamination for expansion and the scarce survival after transplant. In this context, platelet-rich plasma (PRP) could offer advantages. Here, we compare the effects of PRP or standard culture media on C2C12 myoblast, satellite cell and BM-MSC viability, survival, proliferation and myogenic differentiation and evaluate PRP/BM-MSC combination effects in promoting myogenic differentiation. PRP induced an increase of mitochondrial activity and Ki67 expression comparable or even greater than that elicited by standard media and promoted AKT signaling activation in myoblasts and BM-MSCs and Notch-1 pathway activation in BM-MSCs. It stimulated MyoD, myogenin, α-sarcomeric actin and MMP-2 expression in myoblasts and satellite cell activation. Notably, PRP/BM-MSC combination was more effective than PRP alone. We found that BM-MSCs influenced myoblast responses through a paracrine activation of AKT signaling, contributing to shed light on BM-MSC action mechanisms. Our results suggest that PRP represents a good serum substitute for BM-MSC manipulation in vitro and could be beneficial towards transplanted cells in vivo. Moreover, it might influence muscle resident progenitors' fate, thus favoring the endogenous repair/regeneration mechanisms. Finally, within the limitations of an in vitro experimentation, this study provides an experimental background for considering the PRP/BM-MSC combination as a potential therapeutic tool for skeletal muscle damage, combining the beneficial effects of BM-MSCs and PRP on muscle tissue, while potentiating BM-MSC functionality.

Platelet-rich plasma has beneficial effects in mice with osteonecrosis of the femoral head by promoting angiogenesis

Platelet-rich plasma (PRP) is autologous and multifunctional. Platelet concentrate from blood contains highly concentrated platelets and various types of cells, including growth factors. PRP promotes the recovery of cell proliferation and differentiation. Osteonecrosis of the femoral head is a disease caused by femoral head damage or an insufficient blood supply, which leads to the death of bone cells and abnormal bone marrow composition. The subsequent repair of bone cells may result in changes to the structure of femoral head, femoral head collapse and joint dysfunction. PRP may promote the repair of injured articular cartilage in patients with joint diseases through the removal of harmful inflammatory factors. In the present study, the therapeutic effects and primary mechanism of PRP action were investigated using a glucocorticoid-induced femoral head osteonecrosis mouse model. Dexamethasone (DEX) and phosphate-buffered saline were used as controls. The therapeutic efficacy of PRP to treat osteonecrosis in murine femoral heads was evaluated by assessing clinical arthritis scores. The present study indicated that mice with osteonecrosis of the femoral head treated with PRP exhibited downregulated expression of interleukin (IL)-17A, IL-1β, tumor necrosis factor-α, receptor activator of nuclear factor κ-B ligand, IL-6 and interferon-γ in the inflammatory tissue. In addition, the levels of hepatocyte growth factor, intercellular adhesion molecule-1, osteopontin, platelet-derived endothelial cell growth factor, vascular endothelial growth factor, platelet-derived growth factor, insulin-like growth factor-1 and transforming growth factor-β were increased following treatment with PRP. Joint tissue histological staining demonstrated that PRP alleviated osteonecrosis of the femoral head and reduced humoral and cellular immune responses that promoted beneficial effects on the histological parameters. Furthermore, the concentration of glucocorticoids were significantly decreased in the serum of PRP-treated mice with osteonecrosis compared with the DEX group (P<0.01). Notably, PRP promoted beneficial effects in mice with osteonecrosis of the femoral head by stimulating angiogenesis. Therefore, the present study indicated that treatment with PRP promotes beneficial effects by preventing joint inflammation, cartilage destruction and bone damage, and stimulating the repair of joint tissue in mice with osteonecrosis of the femoral head. These preclinical data suggest that PRP may be developed as a novel method of treating osteonecrosis of the femoral head.

Autologous platelet-rich plasma versus conventional therapy for the treatment of chronic venous leg ulcers: A comparative study

BACKGROUND

Chronic venous leg ulcers drastically reduce the quality of life of affected patients. There is heightened interest in autologous platelet-rich plasma (PRP) as one of the promising therapies for leg ulcers.

AIM

Our aim was to compare the clinical efficacy of PRP in the management of chronic venous leg ulcers vs conventional treatment.

PATIENTS/METHODS

In total, 40 patients with chronic venous leg ulcers were included in the study. Twenty patients were treated with autologous PRP weekly for 6 weeks (Group A), and 20 patients were treated with conventional treatment (compression and dressing) for 6 weeks (Group B). Treatment results were calculated by percentage of improvement in area of the ulcer.

RESULTS

Compared to conventional therapy, a highly significant improvement in the ulcer size was observed post-PRP therapy (P-value = .0001). The mean change in the area of the ulcer post-PRP and conventional therapy was 4.92 ± 11.94 cm and 0.13 ± 0.27 cm, respectively, while the mean percentage improvement in the area of the ulcer post-PRP and conventional therapy was 67.6% ± 36.6% and 13.67% ± 28.06%, respectively. Subjective improvement in pain associated with the ulcer was noted by all patients.

CONCLUSIONS

Platelet-rich plasma is a safe nonsurgical procedure for treating chronic venous leg ulcers. Additional studies with larger sample size and longer follow-up periods are required to confirm or refute our findings.

Platelet-rich plasma exhibits beneficial effects for rheumatoid arthritis mice by suppressing inflammatory factors

Platelet-rich plasma (PRP) is a multifunctional blood product containing highly concentrated platelets, and various cell growth factors which promote cell proliferation and differentiation. PRP exhibited benefits in injurious articular cartilage repair and the removal of inflammatory factors in clinical studies. Rheumatoid arthritis (RA) is an autoimmune disease manifesting primarily as inflammatory arthritis, which is associated with notable morbidity in humans. In the present study, the therapeutic effects and primary mechanism of PRP on a type II collagen‑induced arthritis (CIA) mouse model was investigated. Inflammatory factors interleukin (IL)‑6, IL‑8, IL‑17, IL‑1β, tumor necrosis factor (TNF)‑α and interferon (IFN)‑γ were analyzed in PRP and PBS‑treated groups. Vascular endothelial growth factor (VEGF), platelet‑derived growth factor (PDGF), insulin‑like growth factor (IGF)‑1 and transforming growth factor (TGF)‑β expression in peripheral whole blood was additionally analyzed. The therapeutic efficacy of PRP for RA mice was evaluated using clinical arthritis scores. The results of the present study demonstrated that treatment with PRP alleviated arthritis, and reduced humoral and cellular immune responses, leading to beneficial effects on histological parameters as observed using joint tissue histological staining. CIA mice treated with PRP exhibited downregulated expression of IL‑6, IL‑8, IL‑17A, IL‑1β, TNF‑α, receptor activator for nuclear factor‑κB and IFN‑γ in inflammatory tissue. In addition, VEGF, PDGF, IGF‑1 and TGF‑β expression in peripheral whole blood was increased following treatment with PRP. The serum concentration of anti‑collagen antibody was decreased in PRP‑treated CIA mice. In conclusion, CIA mice treated with PRP exhibited beneficial effects, including decreased joint inflammation, cartilage destruction and bone damage, and increased repair of joint tissue. The results of the present study suggested that PRP may be an effective therapeutic agent for RA.

Treatment of chronic non-healing ulcers using autologous platelet rich plasma: a case series

Background

Non-healing ulcers are a major health problem worldwide and have great impact at personal, professional and social levels, with high cost in terms of human and material resources. Recalcitrant non-healing ulcers are inevitable and detrimental to the lower limb and are a major cause of non-traumatic lower limb amputations. Application of autologous Platelet Rich Plasma (PRP) has been a major breakthrough for the treatment of non-healing and diabetic foot ulcers, as it is an easy and cost-effective method, and provides the necessary growth factors that enhance tissue healing. PRP is a conglomeration of thrombocytes, cytokines and various growth factors which are secreted by α-granules of platelets that augment the rate of natural healing process with decrease in time. The purpose of this case series was to evaluate the safety and efficacy of autologous platelet rich plasma for the treatment of chronic non-healing ulcers on the lower extremity.

Methods

Autologous PRP was prepared from whole blood utilizing a rapid, intraoperative point-of-care system that works on the principle of density gradient centrifugation. Twenty Four (24) patients with non-healing ulcers of different etiologies, who met the inclusion criteria, were treated with single dose of subcutaneous PRP injections along with topical application of PRP gel under compassionate use.

Results

The mean age of the treated patients was 62.5 ± 13.53 years and they were followed-up for a period of 24 weeks. All the patients showed signs of wound healing with reduction in wound size, and the mean time duration to ulcer healing was 8.2 weeks. Also, an average five fold increase in the platelet concentrate was observed in the final PRP product obtained using the rapid point-of-care device, and the average platelet dose administered to the patients was 70.10 × 10⁸.

Conclusion

This case series has demonstrated the potential safety and efficacy of autologous platelet rich plasma for the treatment of chronic non-healing ulcers.

Trial registration

NCT03026855, Registered 4 January 2017 ‘Retrospectively’

Platelet gel: a new therapeutic tool with great potential

Chronic wounds, such as diabetic foot ulcers, represent a serious clinical problem for patients and clinicians. Management of these wounds has a strong economic impact worldwide. Complications resulting from injuries are a frequent cause of morbidity and mortality. Chronic wounds lead to infections, painful dressings and prolonged hospitalisation. This results in poor patient Quality of Life and in high healthcare costs. Platelet concentrates (PC) are defined as autologous or allogeneic platelet derivatives with a platelet concentration higher than baseline. PC are widely used in different areas of Regenerative Medicine in order to enhance wound healing processes; they include platelet-rich plasma (PRP), platelet gel (PG), platelet-rich fibrin (PRF), serum eye drops (E-S), and PRP eye drops (E-PRP). This review highlights the use of platelet-rich plasma (PRP) and platelet gel (PG) preparation for clinical use.

Autologous platelet-rich plasma for treating chronic wounds

BACKGROUND

Autologous platelet-rich plasma (PRP) is a treatment that contains fibrin and high concentrations of growth factors with the potential to improve the healing of chronic wounds. This is the first update of a review first published in 2012.

OBJECTIVES

To determine whether autologous PRP promotes the healing of chronic wounds.

SEARCH METHODS

In June 2015, for this first update, we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library): Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. We also searched for ongoing and unpublished clinical trials in the WHO International Clinical Trials Registry Platform (ICTRP) (searched January 2015). We did not impose any restrictions with respect to language, date of publication, or study setting.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared autologous PRP with placebo or alternative treatments for any type of chronic wound in adults. We did not apply any date or language restrictions.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology, including two reviewers independently selecting studies for inclusion, extracting data, and assessing risk of bias.

MAIN RESULTS

The search identified one new RCT, making a total of 10 included RCTs (442 participants, 42% women). The median number of participants per RCT was 29 (range 10 to 117). Four RCTs recruited people with a range of chronic wounds; three RCTs recruited people with venous leg ulcers, and three RCTs considered foot ulcers in people with diabetes. The median length of treatment was 12 weeks (range 8 to 40 weeks).It is unclear whether autologous PRP improves the healing of chronic wounds generally compared with standard treatment (with or without placebo) (risk ratio (RR) 1.19, 95% confidence interval (CI) 0.95 to 1.50; I(2) = 27%, low quality evidence, 8 RCTs, 391 participants). Autologous PRP may increase the healing of foot ulcers in people with diabetes compared with standard care (with or without placebo) (RR 1.22, 95% CI 1.01 to 1.49; I(2) = 0%, low quality evidence, 2 RCTs, 189 participants). It is unclear if autologous PRP affects the healing of venous leg ulcers (RR 1.02, 95% CI 0.81 to 1.27; I(2) = 0% ). It is unclear if there is a difference in the risk of adverse events in people treated with PRP or standard care (RR 1.05, 95% CI 0.29 to 3.88; I(2) = 0%, low quality evidence from 3 trials, 102 participants).

AUTHORS' CONCLUSIONS

PRP may improve the healing of foot ulcers associated with diabetes, but this conclusion is based on low quality evidence from two small RCTs. It is unclear whether PRP influences the healing of other chronic wounds. The overall quality of evidence of autologous PRP for treating chronic wounds is low. There are very few RCTs evaluating PRP, they are underpowered to detect treatment effects, if they exist, and are generally at high or unclear risk of bias. Well designed and adequately powered clinical trials are needed.