The application of platelet-rich plasma in the treatment of deep dermal burns: A randomized, double-blind, intra-patient controlled study

Fat Grafting and Regenerative Medicine in Burn Care

Regenerative therapies such as fat grafting and Platelet Rich Plasma (PRP) have emerged as new options to tackle burn-related injuries and their long-term sequelae. Fat grafting is able to promote wound healing by regulating the inflammatory response, stimulating angiogenesis, favoring the remodeling of the extracellular matrix, and enhancing scar appearance. PRP can enhance wound healing by accelerating stages including hemostasis and re-epithelization. It can improve scar quality and complement fat grafting procedures. Their cost-effectiveness, minimal invasiveness, and promising results observed in the literature have made these tools as therapeutic candidates. The current evidence on fat grafting and PRP in acute and reconstructive burns is described and discussed in this study.

Interventions for postburn pruritus

BACKGROUND

Postburn pruritus (itch) is a common and distressing symptom experienced on healing or healed burn or donor site wounds. Topical, systemic, and physical treatments are available to control postburn pruritus; however, it remains unclear how effective these are.

OBJECTIVES

To assess the effects of interventions for treating postburn pruritus in any care setting.

SEARCH METHODS

In September 2022, we searched the Cochrane Wounds Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus. We also searched clinical trials registries and scanned references of relevant publications to identify eligible trials. There were no restrictions with respect to language, publication date, or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that enrolled people with postburn pruritus to compare an intervention for postburn pruritus with any other intervention, placebo or sham intervention, or no intervention.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included 25 RCTs assessing 21 interventions with 1166 randomised participants. These 21 interventions can be grouped into six categories: neuromodulatory agents (such as doxepin, gabapentin, pregabalin, ondansetron), topical therapies (such as CQ-01 hydrogel, silicone gel, enalapril ointment, Provase moisturiser, beeswax and herbal oil cream), physical modalities (such as massage therapy, therapeutic touch, extracorporeal shock wave therapy, enhanced education about silicone gel sheeting), laser scar revision (pulsed dye laser, pulsed high-intensity laser, fractional CO2 laser), electrical stimulation (transcutaneous electrical nerve stimulation, transcranial direct current stimulation), and other therapies (cetirizine/cimetidine combination, lemon balm tea). Most RCTs were conducted at academic hospitals and were at a high risk of performance, attrition, and detection bias. While 24 out of 25 included studies reported change in burn-related pruritus, secondary outcomes such as cost-effectiveness, pain, patient perception, wound healing, and participant health-related quality of life were not reported or were reported incompletely. Neuromodulatory agents versus antihistamines or placebo There is low-certainty evidence that doxepin cream may reduce burn-related pruritus compared with oral antihistamine (mean difference (MD) -2.60 on a 0 to 10 visual analogue scale (VAS), 95% confidence interval (CI) -3.79 to -1.42; 2 studies, 49 participants). A change of 2 points represents a minimal clinically important difference (MCID). Due to very low-certainty evidence, it is uncertain whether doxepin cream impacts the incidence of somnolence as an adverse event compared to oral antihistamine (risk ratio (RR) 0.64, 95% CI 0.32 to 1.25; 1 study, 24 participants). No data were reported on pain in the included study. There is low-certainty evidence that gabapentin may reduce burn-related pruritus compared with cetirizine (MD -2.40 VAS, 95% CI -4.14 to -0.66; 1 study, 40 participants). A change of 2 points represents a MCID. There is low-certainty evidence that gabapentin reduces the incidence of somnolence compared to cetirizine (RR 0.02, 95% CI 0.00 to 0.38; 1 study, 40 participants). No data were reported on pain in the included study. There is low-certainty evidence that pregabalin may result in a reduction in burn-related pruritus intensity compared with cetirizine with pheniramine maleate (MD -0.80 VAS, 95% CI -1.24 to -0.36; 1 study, 40 participants). A change of 2 points represents a MCID. There is low-certainty evidence that pregabalin reduces the incidence of somnolence compared to cetirizine (RR 0.04, 95% CI 0.00 to 0.69; 1 study, 40 participants). No data were reported on pain in the included study. There is moderate-certainty evidence that ondansetron probably results in a reduction in burn-related pruritus intensity compared with diphenhydramine (MD -0.76 on a 0 to 10 numeric analogue scale (NAS), 95% CI -1.50 to -0.02; 1 study, 38 participants). A change of 2 points represents a MCID. No data were reported on pain and adverse events in the included study. Topical therapies versus relevant comparators There is moderate-certainty evidence that enalapril ointment probably decreases mean burn-related pruritus compared with placebo control (MD -0.70 on a 0 to 4 scoring table for itching, 95% CI -1.04 to -0.36; 1 study, 60 participants). No data were reported on pain and adverse events in the included study. Physical modalities versus relevant comparators Compared with standard care, there is low-certainty evidence that massage may reduce burn-related pruritus (standardised mean difference (SMD) -0.86, 95% CI -1.45 to -0.27; 2 studies, 166 participants) and pain (SMD -1.32, 95% CI -1.66 to -0.98). These SMDs equate to a 4.60-point reduction in pruritus and a 3.74-point reduction in pain on a 10-point VAS. A change of 2 VAS points in itch represents a MCID. No data were reported on adverse events in the included studies. There is low-certainty evidence that extracorporeal shock wave therapy (ESWT) may reduce burn-related pruritus compared with sham stimulation (SMD -1.20, 95% CI -1.65 to -0.75; 2 studies, 91 participants). This equates to a 5.93-point reduction in pruritus on a 22-point 12-item Pruritus Severity Scale. There is low-certainty evidence that ESWT may reduce pain compared with sham stimulation (MD 2.96 on a 0 to 25 pressure pain threshold (PPT), 95% CI 1.76 to 4.16; 1 study, 45 participants). No data were reported on adverse events in the included studies. Laser scar revision versus untreated or placebo controls There is moderate-certainty evidence that pulsed high-intensity laser probably results in a reduction in burn-related pruritus intensity compared with placebo laser (MD -0.51 on a 0 to 1 Itch Severity Scale (ISS), 95% CI -0.64 to -0.38; 1 study, 49 participants). There is moderate-certainty evidence that pulsed high-intensity laser probably reduces pain compared with placebo laser (MD -3.23 VAS, 95% CI -5.41 to -1.05; 1 study, 49 participants). No data were reported on adverse events in the included studies.

AUTHORS' CONCLUSIONS

There is moderate to low-certainty evidence on the effects of 21 interventions. Most studies were small and at a high risk of bias related to blinding and incomplete outcome data. Where there is moderate-certainty evidence, practitioners should consider the applicability of the evidence for their patients.

How to evaluate scar colour after burn injuries - A clinical comparison of the Mexameter® and the subjective scar assessment (POSAS/VSS)

INTRODUCTION

Scarring after burn injuries remains one of the major challenges in burn medicine and is the subject of current research. Accurate and high-quality assessment of scars is needed to enable exact outcome evaluation of different treatments. Our aim was to evaluate the most common subjective scar evaluation scores-the POSAS (Patient and Observer Scar Assessment Scale) and VSS (Vancouver Scar Scale)-in comparison with the objective device Mexameter® for colour evaluation.

METHODS

A prospective monocentre study was performed, which included 120 examined scar areas of 60 patients with third degree burns who had received skin grafts between 1975 and 2018 with a total burned surface area (TBSA) > 2%. Two different scar areas in comparison with one healthy skin area concerning 'colour', 'pigmentation', and 'vascularization' were evaluated by the Mexameter® MX 18, the OSAS, and the VSS by the same examiner, as well as the PSAS by the patient.

RESULTS

The mean TBSA of the 60 patients was 24.3%. In the OSAS, 61% of the scars were evaluated as 'hyper-', 19% as 'hypo-', and 19% as 'mix-pigmented'. Furthermore, 65% of the scars were estimated as highly vascularized. In the Mexameter®, the melanin index values of the scar areas compared to the healthy skin areas showed a small difference of 12 (p < 0.05). The mean difference of erythema between the scar and the healthy skin areas was 84 (p < 0.001). For the Mexameter®, moderate correlations were found when comparing 'erythema' with the OSAS category 'vascularization' (r = 0.33, p < 0.05) and 'melanin' with the OSAS parameter 'pigmentation' (r = 0.28, p < 0.05). When comparing the Mexameter® measurements to the OSAS questionnaire, 27% of the scars were wrongly evaluated as 'hyperpigmented' by the observer and 21% as 'hypervascularized', while showing low measurements in the device. Additionally, a novel Mexameter® ordinal scare scale was calculated.

CONCLUSION

In this study, we were able to show on a relatively large patient population that with the Mexameter®, the subjectivity of the scar colour assessment by examiner/patient can be overcome, but precise differentiation can still be ensured with subjective evaluation tools. We further introduced a novel Mexameter® Scar Scale. It is necessary to further investigate the vast range of objective devices and develop scar panels for with an incorporation of objective and subjective devices to further improve reliability with reduced bias in terms of scar assessment.

The Benefits of Using Platelet-rich Plasma with Dermal Substitutes for Extremity Posttraumatic Skin Defects: A Short-term Outcome

Background

Skin injuries are very common. Skin grafting is an ongoing wound management procedure. The artificial dermis, PELNAC, has been considered in the treatment of several acute and chronic skin injuries. Platelet-rich plasma (PRP) is blood plasma with a platelet count higher than the baseline. It is presumed to act in a synergetic pattern to promote the healing of wounds. This study was conducted to assess the potential benefit of adding PRP to PELNAC as adjuvant therapy in treating posttraumatic skin.

Methods

In this study, adult patients who were admitted to the hospital with extremity traumatic skin and soft tissue defects with exposed bare bone, exposed tendons, or exposed cartilage in the period between October 2019 and March 2021 were allocated to either being managed with dermal substitute (PELNAC) together with PRP (group I) or PELNAC alone (group II).

Results

Patients in group I showed a higher mean graft take rate and a lower mean time for neovascularization of the acellular dermal matrix, with a statistically highly significant difference. The Vancouver Scar Scale values showed no significant difference in either group. The PRP-treated group showed statistically significant shorter hospital stays.

Conclusions

The addition of PRP to the treatment protocol showed better outcomes in terms of graft take rate, time for neovascularization of acellular dermal matrix, and length of hospital stay, with no side effects. The present study findings emphasize the promising outcome of PRP in addition to the standard treatment of complex wounds to achieve rapid and safe healing.

Efficiency of platelet-rich plasma in the management of burn wounds: A meta-analysis

The meta-analysis aimed to assess the efficiency of platelet-rich plasma (PRP) in the management of burn wounds (BWs). Using dichotomous or contentious random- or fixed-effects models, the outcomes of this meta-analysis were examined and the odds ratio (OR) and the mean difference (MD) with 95% confidence intervals (CIs) were computed. Thirteen examinations from 2009 to 2023 were enrolled for the present meta-analysis, including 808 individuals with BWs. PRP had significantly shorter healing time (MD, -5.80; 95% CI, -7.73 to -3.88, p < 0.001), higher healing rate (OR, 3.14; 95% CI, 2.05-4.80, p < 0.001), higher healed area percent (MD, 12.67; 95% CI, 9.79-15.55, p < 0.001) and higher graft take area percent (MD, 4.39; 95% CI, 1.51-7.26, p = 0.003) compared with standard therapy in patients with BW. However, no significant difference was found between PRP and standard therapy in graft take ratio (OR, 1.70; 95% CI, 0.86-3.34, p = 0.13) and infection rate (OR, 0.55; 95% CI, 0.20-1.47, p = 0.23) in patients with BW. The examined data revealed that PRP had a significantly shorter healing time, a higher healing rate, a higher healed area percent and a higher graft take area percent; however, no significant difference was found in graft take ratio or infection rate compared with standard therapy in patients with BW. Yet, attention should be paid to its values since all of the selected examinations had a low sample size and some comparisons had a low number of selected studies.

Therapeutic role of mesenchymal stem cells and platelet-rich plasma on skin burn healing and rejuvenation: A focus on scar regulation, oxido-inflammatory stress and apoptotic mechanisms

Cell-based therapies have great promise in accelerating and improving burn wound healing. It is a growing need to scale their competence to meet the clinical demands. In this study, the bone marrow mesenchymal stem cells (BMSCs) and platelet-rich plasma (PRP) were tested on the repair of induced burn wounds in a murine model. After the induction of thermal injury, rats were injected with BMSCs and/or PRP in the burn area. After 4 weeks of post-burn, our findings revealed that local treatment of burnt skin with BMSCs and/or PRP offered substantial outcomes when compared with the untreated group. Injected burn with BMSCs and/or PRP enhanced the wound contraction rate and decreased the burn area and period of epithelization. Significant increases in VEGF together with declines in MMP-9 and TGF-β1 were observed in burnt areas after being treated with BMSCs and/or PRP therapy that indicated improved angiogenesis, and re-epithelization. Furthermore, both MSCs and PRP modulated the burn's oxidative and inflammatory microenvironment as indicated by increases in SOD, CAT, and GSH besides declines in MDA, IL-6, TNF-α, NF-κB, NO, and iNOS. Notable increases in Bcl-2 levels and decreases in Cas-3 and Bax levels were recorded in burnt skin that received both agents concomitantly. Interestingly, the histopathological examination validates the healing power of BMSCs and/or PRP. Collectively, BMSCs and PRP have pioneered therapeutics candidates for clinical application in burn healing possibly via antioxidant, anti-inflammatory, and anti-apoptotic mechanisms along with regulating angiogenesis and scar formation.

First-in-human clinical trial of allogeneic, platelet-derived extracellular vesicles as a potential therapeutic for delayed wound healing

The release of growth factors, cytokines and extracellular matrix modifiers by activated platelets is an important step in the process of healthy wound healing. Extracellular vesicles (EVs) released by activated platelets carry this bioactive cargo in an enriched form, and may therefore represent a potential therapeutic for the treatment of delayed wound healing, such as chronic wounds. While EVs show great promise in regenerative medicine, their production at clinical scale remains a critical challenge and their tolerability in humans is still to be fully established. In this work, we demonstrate that Ligand-based Exosome Affinity Purification (LEAP) chromatography can successfully isolate platelet EVs (pEVs) of clinical grade from activated platelets, which retain the regenerative properties of the parent cell. LEAP-isolated pEVs display the expected biophysical features of EV populations and transport essential proteins in wound healing processes, including insulin growth factor (IGF) and transforming growth factor beta (TGF-ß). In vitro studies show that pEVs induce proliferation and migration of dermal fibroblasts and increase dermal endothelial cells' angiogenic potential, demonstrating their wound healing potential. pEV treatment activates the ERK and Akt signalling pathways within recipient cells. In a first-in-human, double-blind, placebo-controlled, phase I clinical trial of healthy volunteer adults, designed primarily to assess safety in the context of wound healing, we demonstrate that injections of LEAP-purified pEVs in formulation buffer are safe and well tolerated (Plexoval II study, ACTRN12620000944932). As a secondary objective, biological activity in the context of wound healing rate was assessed. In this cohort of healthy participants, in which the wound bed would not be expected to be deficient in the bioactive cargo that pEVs carry, all wounds healed rapidly and completely and no difference in time to wound closure of the treated and untreated wounds was observed at the single dose tested. The outcomes of this study evidence that pEVs manufactured through the LEAP process can be injected safely in humans as a potential wound healing treatment, and warrant further study in clinical trials designed expressly to assess therapeutic efficacy in patients with delayed or disrupted wound healing.

Autologous Skin Grafts, versus Tissue-engineered Skin Constructs: A Systematic Review and Meta-analysis

For over 100 years, autologous skin grafts have remained the gold standard for the reconstruction of wounds but are limited in availability. Acellular tissue-engineered skin constructs (acellular TCs) and cellular tissue-engineered skin constructs (cellular TCs) may address these limitations. This systematic review and meta-analysis compare outcomes between them.

Methods

A systematic review was conducted using PRISMA guidelines, querying MEDLINE, Embase, Web of Science, and Cochrane to assess graft incorporation, failure, and wound healing. Case reports/series, reviews, in vitro/in vivo work, non-English articles or articles without full text were excluded.

Results

Sixty-six articles encompassing 4076 patients were included. No significant differences were found between graft failure rates (P = 0.07) and mean difference of percent reepithelialization (p = 0.92) when split-thickness skin grafts were applied alone versus co-grafted with acellular TCs. Similar mean Vancouver Scar Scale was found for these two groups (p = 0.09). Twenty-one studies used at least one cellular TC. Weighted averages from pooled results did not reveal statistically significant differences in mean reepithelialization or failure rates for epidermal cellular TCs compared with split-thickness skin grafts (p = 0.55).

Conclusions

This systematic review is the first to illustrate comparable functional and wound healing outcomes between split-thickness skin grafts alone and those co-grafted with acellular TCs. The use of cellular TCs seems promising from preliminary findings. However, these results are limited in clinical applicability due to the heterogeneity of study data, and further level 1 evidence is required to determine the safety and efficacy of these constructs.

Role for platelet rich plasma as an adjuvant therapy in wound healing and burns

Background

Platelet rich plasma (PRP) contains high concentrations of growth factors. Intuitively, these were thought to be of potential benefit in healing of chronic wounds, skin grafts and graft donor sites. This was echoed in retrospective studies and an individual case basis but had not been randomized.

Methods

A systematic search was carried out by two individuals, independently, on the MEDLINE, EMBASE and COCHRANE databases, according to PRISMA guidelines. All data analysis and statistics was pooled and analysed using the Cochrane RevMan Software.

Results

Split thickness grafts have been described by numerous authors, but PRP use did not offer a significant advantage in graft take in pooled results (MD 5.83, 95% CI − 0.69 to 12.25, random-effects, p = 0.08). The analysis of included randomized controlled trials has shown favourable split-thickness skin graft donor site healing in the PRP group (MD − 5.55, 95% CI − 7.40 to − 3.69, random-effects, p =  < 0.00001) compared to the control group. For carpal tunnel syndrome, the pooled results showed no difference in functional scores vs steroid injections (SMD − 0.68, 95% CI − 1.47 to 0.10, randomeffects, p = 0.09) or indeed splinting groups.

Conclusions

With the current body of evidence, we conclude that the use of PRP as an adjuvant therapy in skin grafts, burns, carpal tunnel surgery or scars cannot be rationalised. A potential use of PRP is in donor site management but the cost of this would be difficult to justify.

Level of evidence: Not ratable.

The effects of mesenchymal stromal cells and platelet-rich plasma treatments on cutaneous wound healing

Cellular therapy and platelet-rich plasma (PRP) have been used as a treatment for skin wounds. Previous evidence has shown that mesenchymal stromal cells (MSC) may improve skin wound healing. In contrast, contradictory effects have been reported by using PRP treatment on skin wound healing. However, there is evidence that PRP constitutes an excellent scaffold for tissue engineering. In this work, we aim to study the effect of MSC on skin wound healing. We used an experimental murine model of full-thickness wounds. Wounds were treated with human bone marrow-MSC contained in a PRP clot. Untreated or PRP-treated wounds were used as controls. Wound healing was evaluated by macroscopic observation and histological analysis at day 7 post-wounding. Immunohistochemical studies were performed to detect the presence of epithelial progenitor cells (EPC) and the expression of basic fibroblast growth factor (bFGF). MSC/PRP implantation induced a significant wound closure and re-epithelialization as compared with the controls. Increase of CD34⁺ cells and bFGF was observed in the wounds treated with MSC/PRP. Our results show that MSC included in PRP clot induce cutaneous wound repair by promoting re-epithelialization, migration of EPC and expression of bFGF. PRP alone does not exert a significant effect on wound healing. Our results support the possible clinical use of MSC in PRP scaffold as potential treatment of skin wounds.

Emerging treatment strategies in wound care

Wound healing is a complex process in tissue regeneration through which the body responds to the dissipated cells as a result of any kind of severe injury. Diabetic and non-healing wounds are considered an unmet clinical need. Currently, different strategic approaches are widely used in the treatment of acute and chronic wounds which include, but are not limited to, tissue transplantation, cell therapy and wound dressings, and the use of an instrument. A large number of literatures have been published on this topic; however, the most effective clinical treatment remains a challenge. The wound dressing involves the use of a scaffold, usually using biomaterials for the delivery of medication, autologous stem cells, or growth factors from the blood. Antibacterial and anti-inflammatory drugs are also used to stop the infection as well as accelerate wound healing. With an increase in the ageing population leading to diabetes and associated cutaneous wounds, there is a great need to improve the current treatment strategies. This research critically reviews the current advancement in the therapeutic and clinical approaches for wound healing and tissue regeneration. The results of recent clinical trials suggest that the use of modern dressings and skin substitutes is the easiest, most accessible, and most cost-effective way to treat chronic wounds with advances in materials science such as graphene as 3D scaffold and biomolecules hold significant promise. The annual market value for successful wound treatment exceeds over $50 billion US dollars, and this will encourage industries as well as academics to investigate the application of emerging smart materials for modern dressings and skin substitutes for wound therapy.

Healing Mechanisms in Cutaneous Wounds: Tipping the Balance

Acute and chronic cutaneous wounds pose a significant health and economic burden. Cutaneous wound healing is a complex process that occurs in four distinct, yet overlapping, highly coordinated stages: hemostasis, inflammation, proliferation, and remodeling. Postnatal wound healing is reparative, which can lead to the formation of scar tissue. Regenerative wound healing occurs during fetal development and in restricted postnatal tissues. This process can restore the wound to an uninjured state by producing new skin cells from stem cell reservoirs, resulting in healing with minimal or no scarring. Focusing on the pathophysiology of acute burn wounds, this review highlights reparative and regenerative healing mechanisms (including the role of cells, signaling molecules, and the extracellular matrix) and discusses how components of regenerative healing are being used to drive the development of novel approaches and therapeutics aimed at improving clinical outcomes. Important components of regenerative healing, such as stem cells, growth factors, and decellularized dermal matrices, are all being evaluated to recapitulate more closely the natural regenerative healing process.

Role of MSC-derived small extracellular vesicles in tissue repair and regeneration

Mesenchymal stem cells (MSCs) are crucial for tissue homeostasis and repair, secreting vesicles to the extracellular environment. Isolated exosomes were shown to affect angiogenesis, immunomodulation and tissue regeneration. Numerous efforts have been dedicated to describe the mechanism of action of these extracellular vesicles (EVs) and guarantee their safety, since the final aim is their therapeutic application in the clinic. The major advantage of applying MSC-derived EVs is their low or inexistent immunogenicity, prompting their use as drug delivery or therapeutic agents, as well as wound healing, different cancer types, and inflammatory processes in the neurological and cardiovascular systems. MSC-derived EVs display no vascular obstruction effects or apparent adverse effects. Their nano-size ensures their passage through the blood-brain barrier, demonstrating no cytotoxic or immunogenic effects. Several in vitro tests have been conducted with EVs obtained from different sources to understand their biology, molecular content, signaling pathways, and mechanisms of action. Application of EVs to human therapies has recently become a reality, with clinical trials being conducted to treat Alzheimer's disease, retina degeneration, and COVID-19 patients. Herein, we describe and compare the different extracellular vesicles isolation methods and therapeutic applications regarding the tissue repair and regeneration process, presenting the latest clinical trial reports.

Subjective Tools for Burn Scar Assessment: An Integrative Review

OBJECTIVE

To review the clinical and scientific literature on the subjective ways of assessing burn scars and describe their main characteristics.

DATA SOURCES

The Latin American, Caribbean Health Sciences Literature, Nursing Database, PubMed, CINAHL, and Scopus and Web of Science databases were used to search for studies published between 2014 and 2018 using descriptors in Portuguese, Spanish, and English.

STUDY SELECTION

After establishing the research question and the location and definition of the studies, as well as accounting for differences among databases and application of filters based on inclusion and exclusion criteria, 886 references remained.

DATA EXTRACTION

Investigators reviewed the titles and abstracts of the sample and selected 188 relevant studies for full review.

DATA SYNTHESIS

Twenty-six subjective forms of assessment were found; most research concerned the Patient and Observer Scar Assessment Scale and the Vancouver Scar Scale.

CONCLUSIONS

The Patient and Observer Scar Assessment Scale and the Vancouver Scar Scale are the most common scales for assessing burn scars and have similar evaluation points such as vascularization, pliability, pigmentation, and height, which are the main parameters that contribute to the general assessment and severity of a scar. There is a need to improve instructions for application of the scales to facilitate better understanding and improve agreement among evaluators.

Assisted therapy with platelet-rich plasma for burn patients: A meta-analysis and systematic review

INTRODUCTION

Platelet-rich plasma (PRP) therapy has been used in different medical fields, but its effectiveness in burn wound healing remains debatable. In this study, we performed a systematic review and meta-analysis of the available evidence on burn patients treated with PRP to evaluate the safety and efficacy of the treatment.

METHODS

Randomized controlled trials evaluating the efficacy of PRP in patients with burn injuries were selected. Eligible retrospective studies were abstracted and assessed for the risk of bias by two reviewers and results of mean time to complete epithelization and wound closure rate in the included studies were analyzed. Studies on the correlation between PRP and burn wound healing published in English or Chinese before March 2020 were retrieved from PubMed.

RESULTS

Eight studies (including 449 patients) met our inclusion criteria. Qualitative analysis revealed that compared with the control group, the PRP group had significantly better wound closure rates at weeks 2 (mean difference (MD): 12.79 [95% confidence interval (CI): 7.08, 18.49]; I2: 0%; p < 0.0001) and 3 (MD: 12.66 [95% CI: 5.97, 19.34]; I2: 55%; p = 0.0002) and time to complete epithelialization (MD: -3.45 [95% CI: -4.87, -2.04] (days); I2: 0%; p < 0.00001). There was no significant difference in infection rate or graft take rate.

CONCLUSIONS

PRP application can accelerate wound closure, however, it has no effect on the rates of wound infection and graft take rate.

Platelet-rich plasma for the treatment of burn wounds: A meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the efficacy and safety of platelet-rich plasma in the treatment of burn wounds through a meta-analysis of randomized controlled trials.

METHODS

We conducted a comprehensive study from electronic medical journal databases. The primary outcome was healing rate, and the secondary outcomes were healing time, adverse events, pain score and scar score. The data was analyzed using Review Manager 5.3 and Stata 12. The odds ratio (OR) among different groups was calculated by using 95 % confidence interval (CI).

RESULTS

We included 8 randomized controlled trials with a total of 539 patients. The results showed that platelet-rich plasma could improve the healing rate of burn wound (OR 4.43, 95 % CI 2.13-9.22). The wound healing time of the platelet-rich plasma treatment group was significantly shorter than that of the conventional treatment group (OR -4.23, 95 % CI -5.48 to -2.98), both the superficial burn (OR -3.80, 95 % CI -4.53 to -3.07) and the deep burn group (OR -4.65, 95 % CI -6.90 to -2.40) had shorter healing time. Otherwise, the incidences of adverse events (OR 0.30, 95 % CI 0.11-0.78), pain score (OR -0.80, 95 % CI -1.40 to -0.21) and scar score (OR -0.38, 95 % CI -0.69 to -0.07) were all better in the platelet rich plasma treatment group.

CONCLUSION

Topical platelet-rich plasma treatment on burn wounds can improve wound healing and reduce the incidence of adverse events. Further research is needed to standardize the preparation and use of platelet-rich plasma and to evaluate the long-term clinical outcome of platelet-rich plasma in the treatment of burn wounds.

The application of platelet-rich plasma for skin graft enrichment: A meta-analysis

Existing evidence demonstrated that the role of platelet-rich plasma (PRP) in skin graft enrichment is uncertain. The aim of this study was to evaluate the efficacy and safety of PRP for skin graft. PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for randomised controlled trials that compared outcomes of skin graft treated with PRP versus those treated with blank controls. The outcomes mainly included the rate of skin graft take, number of skin graft loss and haematoma formation, and complications. There were 11 studies involving a total of 910 cases of skin grafts. Compared with the control group, PRP group had a significantly higher rate of skin graft take (mean difference = 5.47%; 95% confidence interval [CI], 2.80%-8.14%; P < .0001), fewer number of skin graft loss (risk ratio [RR] = 0.26; 95% CI, 0.13-0.55; P = .0004) and fewer cases of haematoma formation (RR = 0.24; 95% CI, 0.11-0.54; P = .0006). There was no significant difference in the incidence of complications between two groups. This meta-analysis summarises current evidence and indicates that PRP is a safe and effective adjuvant for skin graft enrichment.

Healing of deep dermal burns by allogeneic mesenchymal stromal cell transplantation

BACKGROUND

Deep dermal and full-thickness burns are not only difficult to treat, but they are also associated with significant morbidity and mortality. Recent reports have proposed the use of mesenchymal stromal cells (MSCs) for inducing tissue repair in burn injuries.

OBJECTIVE

We aim to evaluate the effect of allogeneic MSC transplantation on full-thickness burns with delayed healing.

MATERIAL AND METHODS

This study includes five patients with AB B/B burns. All patients received conservative treatments, including cleaning, debridement of necrotic tissue, and silver based dressing on the burn wounds. Cryopreserved allogeneic MSCs were thawed and rapidly expanded and used for application in burned patients. MSCs were implanted into preclotted platelet-rich plasma onto the surface of burn wounds.

RESULTS

All treated burn wounds showed early granulation tissue and rapid re-epithelialization after MSC transplantation. Healing took between 1 and 5 months after MSC transplantation. Repair of burn wounds was associated with slight discoloration of the regenerated skin without hypertrophic scarring or contractures.

CONCLUSION

Our results provide evidence of healing in deep- and full-thickness burns by allogeneic MSC transplantation. Rapid healing of burn patients, after MSC transplantation, improves their quality of life and reduces the length of hospitalization. Future studies incorporating a larger number of patients may confirm the results obtained in this work.

Efficacy of Lyophilised Platelet-Rich Plasma Powder on Healing Rate in Patients With Deep Second Degree Burn Injury: A Prospective Double-Blind Randomized Clinical Trial

Platelet-rich plasma (PRP) is a kind of plasma that is rich in platelets after processing. It includes various growth factors and cytokines, which speed up the process of wound healing and hemostasis. The PRP solution used in this study is diluted from lyophilized PRP powder, which decreased the possibility of contamination, facilitated the storage, and prolonged the storage life. From in vitro fibroblast proliferation testing, the numbers of PRP supplement were performed for 1, 4, and 7 times by continuous replacement of culture medium each day. Four times of lyophilized PRP supplement was selected for clinical study due to sufficient promotion of fibroblast proliferation. Next, 27 patients of deep second-degree burn wound were included in this study. Patients were assigned to two groups: PRP group (n = 15) and control group (n = 12). A concentration of 1.0 × 10 platelets/cm (wound area) according to wound size was sprayed on the wound evenly. Function was mainly assessed by the percentage of wound closure and bacteria picking out rate in 2 and 3 weeks. The wound closure at 3 weeks showed a significant difference in PRP group (P < 0.05). The healing rate of PRP group reached nearly 80% and made a breakthrough of 90% in 3 weeks, showing a significant difference compared with the control group (P < 0.05). Lyophilized PRP can be considered as an effective treatment to increase healing rate in patients with deep second-degree burn injury.

PEGylated Platelet-Free Blood Plasma-Based Hydrogels for Full-Thickness Wound Regeneration

Objective: To develop a cost-effective and clinically usable therapy to treat full-thickness skin injuries. We accomplished this by preparing a viscoelastic hydrogel using polyethylene glycol (PEG)-modified platelet-free plasma (PEGylated PFP) combined with human adipose-derived stem cells (ASCs). Approach: PEGylated PFP hydrogels were prepared by polymerizing the liquid mixture of PEG and PFP±ASCs and gelled either by adding calcium chloride (CaCl₂) or thrombin. Rheological and in vitro studies were performed to assess viscoelasticity and the ability of hydrogels to direct ASCs toward a vasculogenic phenotype, respectively. Finally, a pilot study evaluated the efficacy of hydrogels±ASCs using an athymic rat full-thickness skin wound model. Results: Hydrogels prepared within the range of 11 to 27 mM for CaCl₂ or 5 to 12.5 U/mL for thrombin exhibited a storage modulus of ∼62 to 87 Pa and ∼47 to 92 Pa, respectively. The PEGylated PFP hydrogels directed ASCs to form network-like structures resembling vasculature, with a fourfold increase in perivascular specific genes that were confirmed by immunofluorescent staining. Hydrogels combined with ASCs exhibited an increase in blood vessel density when applied to excisional rat wounds compared with those treated with hydrogels (110.3 vs. 95.6 BV/mm²; p < 0.05). Furthermore, ASCs were identified in the perivascular region associated with newly forming blood vessels. Innovation: This study demonstrates that PFP modified with PEG along with ASCs can be used to prepare cost-effective stable hydrogels, at the bed-side, to treat extensive skin wounds. Conclusion: These results indicate that PEGylated plasma-based hydrogels combined with ASCs may be a potential regenerative therapy for full-thickness skin wounds.

Application of standardized platelet-rich plasma in elderly patients with complex wounds

In recent years, autologous platelet-rich plasma (PRP) derivatives have been used widely in the regeneration and repair of tissue, but a standard definition and preparation method for PRP are lacking. We developed a standardized method using platelet indices as quality-control indicators for PRP preparation. Twenty-one elderly patients (9 males, 12 females) with complex wounds were treated with standardized platelet-rich plasma (S-PRP). The platelet count in PRP after the second centrifugation was 1,069-1,436 × 10⁹ /L. We adjusted the platelet concentration in PRP after a second centrifugation to 1,000 × 10⁹ /L according to a formula using platelet-poor plasma (PPP). The standardized preparation method that we developed gave S-PRP with a relatively uniform platelet concentration. The wounds of 21 patients showed accelerated healing after S-PRP treatment, and there were no obvious side effects during treatment. These data suggest that our preparation method of S-PRP, using platelet indices as quality-control indicators with platelet count of 1,000 × 10⁹ /L could be used for the treatment of complex wounds in the elderly. The preparation method of S-PRP proposed in the present study may be a simple and effective method of PRP quality control.

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.

Systematic review of clinical outcome reporting in randomised controlled trials of burn care

INTRODUCTION

Systematic reviews collate trial data to provide evidence to support clinical decision-making. For effective synthesis, there must be consistency in outcome reporting. There is no agreed set of outcomes for reporting the effect of burn care interventions. Issues with outcome reporting have been identified, although not systematically investigated. This study gathers empirical evidence on any variation in outcome reporting and assesses the need for a core outcome set for burn care research.

METHODS

Electronic searches of four search engines were undertaken from January 2012 to December 2016 for randomised controlled trials (RCTs), using medical subject headings and free text terms including 'burn', 'scald' 'thermal injury' and 'RCT'. Two authors independently screened papers, extracted outcomes verbatim and recorded the timing of outcome measurement. Duplicate outcomes (exact wording ± different spelling), similar outcomes (albumin in blood, serum albumin) and identical outcomes measured at different times were removed. Variation in outcome reporting was determined by assessing the number of unique outcomes reported across all included trials. Outcomes were classified into domains. Bias was reduced using five researchers and a patient working independently and together.

RESULTS

147 trials were included, of which 127 (86.4%) were RCTs, 13 (8.8%) pilot studies and 7 (4.8%) RCT protocols. 1494 verbatim clinical outcomes were reported; 955 were unique. 76.8% of outcomes were measured within 6 months of injury. Commonly reported outcomes were defined differently. Numbers of unique outcomes per trial varied from one to 37 (median 9; IQR 5,13). No single outcome was reported across all studies demonstrating inconsistency of reporting. Outcomes were classified into 54 domains. Numbers of outcomes per domain ranged from 1 to 166 (median 11; IQR 3,24).

CONCLUSIONS

This review has demonstrated heterogeneity in outcome reporting in burn care research which will hinder amalgamation of study data. We recommend the development of a Core Outcome Set.

PROSPERO REGISTRATION NUMBER

CRD42017060908.

Growth Factor Quantification of Platelet-Rich Plasma in Burn Patients Compared to Matched Healthy Volunteers

Platelet rich plasma (PRP) is blood plasma with a platelet concentration above baseline. When activated, PRP releases growth factors involved in all stages of wound healing, potentially boosting the healing process. To expand our knowledge of the effectiveness of PRP, it is crucial to know the content and composition of PRP products. In this study, growth factor quantification measurements of PRP from burn patients and gender- and age-matched controls were performed. The PRP of burn patients showed levels of growth factors comparable to those of the PRP of healthy volunteers. Considerable intra-individual variation in growth factor content was found. However, a correlation was found between the platelet count of the PRP and most of the growth factors measured.

The use of platelets in regenerative medicine and proposal for a new classification system: guidance from the SSC of the ISTH

Autologous and single-donor allogenic platelet preparations are increasingly being used in many areas of regenerative medicine. However, there are few properly controlled randomized clinical trials, and the preparation, content and characteristics of platelet preparations are generally poorly defined and controlled. The Platelet Physiology Subcommittee of the Scientific and Standardization Committee (SSC) of the ISTH formed a working party of experts with the aim of producing consensus recommendations for guidance on the use of platelets in regenerative medicine. Owing to a lack of investigations that provide definitive evidence for the efficacy, definition and use of different platelet preparations in regenerative medicine, there were insufficient data to develop evidence-based guidelines. Therefore, the RAND method was used, which obtains a formal consensus among experts particularly when scientific evidence is absent, scarce and/or heterogeneous. Using this approach, each expert scored as 'appropriate', 'uncertain' or 'inappropriate' a series of 45 statements about the practice of regenerative medicine with platelets, which included different sections on general aspects, platelet preparations, clinical trial design, and potential utility in different clinical scenarios. After presentation and public discussion at SSC meetings, the assessments were further refined to produce final consensus recommendations, which constitute the subject of the present report.

Some patients (and some of us) respond better to some biological therapies: the as yet unsolved conundrum

Very often, treatment for many common musculoskeletal conditions is only palliative, or involves surgery with major shortcomings. Biological interventions—in particular, platelet-rich plasma (PRP) therapies—may well provide more effective treatments, but their actual efficacy is under scrutiny. PRP is biologically unique to each individual depending on endogenous and exogenous factors, including, but not limited to, demographic factors (i.e. age), immune status (i.e. microbiota), metabolic diseases and concomitant medications. All these potential modifiers of the ultimate effects of PRP have been poorly explored, and their relationship with efficacy has not been established.

Advancements in Regenerative Strategies Through the Continuum of Burn Care

Burns are caused by several mechanisms including flame, scald, chemical, electrical, and ionizing and non-ionizing radiation. Approximately half a million burn cases are registered annually, of which 40 thousand patients are hospitalized and receive definitive treatment. Burn care is very resource intensive as the treatment regimens and length of hospitalization are substantial. Burn wounds are classified based on depth as superficial (first degree), partial-thickness (second degree), or full-thickness (third degree), which determines the treatment necessary for successful healing. The goal of burn wound care is to fully restore the barrier function of the tissue as quickly as possible while minimizing infection, scarring, and contracture. The aim of this review is to highlight how tissue engineering and regenerative medicine strategies are being used to address the unique challenges of burn wound healing and define the current gaps in care for both partial- and full-thickness burn injuries. This review will present the current standard of care (SOC) and provide information on various treatment options that have been tested pre-clinically or are currently in clinical trials. Due to the complexity of burn wound healing compared to other skin injuries, burn specific treatment regimens must be developed. Recently, tissue engineering and regenerative medicine strategies have been developed to improve skin regeneration that can restore normal skin physiology and limit adverse outcomes, such as infection, delayed re-epithelialization, and scarring. Our emphasis will be centered on how current clinical and pre-clinical research of pharmacological agents, biomaterials, and cellular-based therapies can be applied throughout the continuum of burn care by targeting the stages of wound healing: hemostasis, inflammation, cell proliferation, and matrix remodeling.

The effects of platelet rich plasma on healing of full thickness burns in swine

INTRODUCTION

Platelet rich plasma (PRP) is rich in growth factors and has been shown to improve healing in a variety of wounds. We determined the effects of PRP on healing and scarring in full thickness porcine burns with and without tangential excision and grafting (TEG).

METHODS

Standardized full thickness 5cm by 5cm burns were created on each of the backs and flanks of 10 anesthetized female pigs (25kg) using a validated model. The burns were created with a heating device that emits heat at a temperature of 400°C for a period of 30s. The burns were randomized to one of six treatments: no TEG or PRP, no TEG+PRP, early (day 2) TEG and no PRP, early TEG+PRP, late (day 14) TEG and no PRP, and late TEG+PRP. Tangential excision was performed down to viable tissue and autografts were 0.2mm thick. When used, a thin layer of autologous PRP was applied below the graft. All wounds were then treated with a topical antibiotic ointment 3 times weekly for 42 days. Digital images and full thickness biopsies were taken at 9, 11, 14, 18, 21, 28, 35 and 42days after injury to determine percentage reepithelialization, scar depth, and scar contraction. Tissue sections were stained with H&E and viewed by a dermatopathologist masked to treatment assignment.

RESULTS

There was no reduction in platelet and white blood cell concentrations in PRP and blood samples for the first 14days after-full thickness burns. A total of 120 burns were created on 10 animals evenly distributed between the six treatment groups. Burns undergoing early TEG reepithelialized fastest and with the thinnest scars followed by late TEG. Burns that did not undergo TEG had the slowest reepithelialization and greatest amount of scarring. Application of PRP had no additional effects on reepithelialization, scar depth, or scar contraction in any of the treatment groups.

CONCLUSIONS

Addition of PRP had similar effects on reepithelialization and scarring of full thickness porcine burns as standard topical antibiotic ointment regardless of whether the burns underwent excision or grafting or the timing of excision and grafting.

Early intervention in scar management and cutaneous burns with autologous platelet-rich plasma

Burn management options are controversial and a multiple-handled issue. However, platelet-rich plasma is gaining interest in several medical fields. Dermatologist worldwide are already publishing some reports about its benefits and personal experiences in their practices. A 40-year-old female with a second-degree burn by VASER-type liposculpture was treated with platelet-rich plasma and followed up for 10 months. After treatment, she showed rapid improvement with an adequate cicatrization results. Some studies suggest that the use of platelet-rich plasma which contains cytokines and growth factors that participate in cellular repair and cellular differentiation, thus improving healing time and re-epithelization. We present the case of a patient with a second-degree burn that rapidly improved with autologous platelet-rich plasma.

Prognostic values of red blood cell distribution width, platelet count, and red cell distribution width-to-platelet ratio for severe burn injury

Red blood cell distribution width (RDW), platelet count (PLT), and a RDW-to-PLT ratio (RPR) have been associated with inflammatory activity and adverse outcomes in many diseases. This study has aimed to investigate the association between these indicators and the mortality rate of severe burn patients. From 2008 to 2014, 610 cases of severe burn patients from two burn centers in eastern China were enrolled in this study. Eighty-eight patients died within 90 days after admission. The RDW, PLT, and RPR were studied through Cox regression analysis on the 3rd and 7th day. The RDW, PLT, and RPR values on the 3rd and 7th day were significantly associated with the outcomes of severe burn patients (P < 0.01). High RPR was significantly associated with a 90-day mortality rate at the two time points. However, the RDW and PLT did not provide independent predictive values. Our results indicated that the RPR values on the 3rd and 7th day were associated with the mortality rates of severe burn patients (P < 0.01). Meanwhile, the RDW and PLT values at these time points failed to provide independent values for burn mortality prediction. Thus, the RPR can serve as an independent and novel marker for mortality rates prediction in severe burn patients.