A systematic review on surgical and nonsurgical debridement techniques of burn wounds

Safety and efficacy of waterjet debridement vs. conventional debridement in the treatment of extremely severe burns: A retrospective analysis

INTRODUCTION

Patients with extremely severe burns often require rapid wound closure with a tangential excision or escharectomy combined with a skin graft to reduce life-threatening complications such as infection. Traditional tangential excision surgery using the Watson or Humby knife does not allow accurate excision of necrotic tissue and often removes too much active tissue, which is detrimental to the rapid healing of the wound. Importantly, the Versajet hydrosurgical system, with its smaller handle, allows for more precise excision of necrotic burn tissue and preserves more active dermal tissue, positively affecting wound healing and scarring. This study compared the safety and efficacy of hydrosurgical combined with autologous skin grafting to conventional excision combined with autologous skin grafting in patients with extremely severe burn.

METHODS

Information of sixty burn patients with total body surface area (TBSA) > 50 % treated at the first affiliated hospital of Anhui Medical University from January 2019 to August 2022 were analyzed. The patients were divided into a conventional debridement group (n = 37) and a hydrosurgical debridement group (n = 23) according to the approach used. The hydrosurgical debridement group and the conventional debridement group were compared from the difference between the duration of the first debridement surgery, wound healing time, the changes of red blood cells and hemoglobin concentration postoperative, total blood transfusion, hospitalization cost, skin grafting frequency, procalcitonin, wound bacterial culture, albumin and prealbumin.

RESULTS

Information on age, gender, weight, inhalation injury, hypovolemic shock, preoperative procalcitonin, preoperative albumin, preoperative prealbumin, the operation frequency (n ≥ 3), preoperative trauma culture and postoperative trauma culture were compared between both groups (P > 0.05). Operative time and wound healing time were significantly shorter in patients with hydrosurgical debridement combined with autologous skin grafting than those in the control group (P < 0.05), while hospitalization costs were not significantly different between the two groups (P > 0.05). The changes of red blood cells and hemoglobin concentration during the postoperative period in the hydrosurgical debridement group were less significantly than those in the conventional debridement group (P < 0.05). The total amount of red blood cells transfused during hospitalization was significantly lower in the hydrosurgical debridement group than that in the conventional debridement group (P < 0.05), but the total amount of fresh frozen plasma transfused during hospitalization was not statistically significant between the two groups (P > 0.05). Albumin on the third day after surgery and prealbumin on the first, third and fifth day after surgery improved more significantly than those in the control group(P < 0.05), however, there were no significant differences between the two groups in albumin on the first and fifth postoperative days (P > 0.05). The PCT level in the conventional debridement group was significantly higher than that in the hydrosurgical debridement group on the first, third and fifth days after surgery(P < 0.05).

CONCLUSION

The hydrosurgical debridement group presented with shorter operative time, less blood loss during surgery, faster postoperative nutritional recovery, less postoperative inflammatory response and faster wounds healing, and did not increase the hospitalization cost, postoperative bacterial culture of the wounds and the number of skin grafting surgeries. In patients with extremely severe burn, hydrosurgical debridement combined with autologous skin grafting group is safer and more effective than those in the conventional debridement combined with autologous skin grafting group.

Bromelain-based enzymatic burn debridement: A systematic review of clinical studies on patient safety, efficacy and long-term outcomes

In 2012 the European Medicines Agency approved a pineapple stem-derived Bromelain-based debridement concentrate of proteolytic enzymes (NexoBrid®, MediWound Ltd, Yavne, Israel) for adult deep burns. Over 10 000 patients have been successfully treated with NexoBrid® globally, including in the US. The aim of our study is to perform a systematic review of the current literature on Nexobrid® outcomes. We conducted a literature search in PubMed, Google Scholar, Embase, and other search engines (2013-2023). The online screening process was performed by two independent reviewers with the Covidence tool. The protocol was reported using the Preferred Reporting Items for Systematic Review and Meta-Analyses, and it was registered at the International Prospective Register of Systematic Reviews of the National Institute for Health Research. We identified 103 relevant studies of which 34 were found eligible. The included studies report the positive effects of Nexobrid® on burn debridement, functional and cosmetic outcomes, scarring, and quality of life. Also, they validate the high patient satisfaction thanks to enhanced protocols of analgosedation and/or locoregional anaesthesia during Bromelain-based debridement. Two studies investigate potential risks (coagulopathy, burn wound infection) which concluded there is no strong evidence of these adverse events. NexoBrid® is a safe, selective, non-surgical eschar removal treatment modality. The benefits of Bromelain-based debridement are faster debridement and healing times, reduced operations, length of stay, cases of sepsis, blood transfusions, and prevention of compartment syndrome. Existing evidence suggests that the indications and the role of Bromelain-based debridement are expanding to cover "off-label" cases with significant benefits to the global healthcare economy.

Acceleration of burn wound healing by micronized amniotic membrane seeded with umbilical cord-derived mesenchymal stem cells

Umbilical cord-derived mesenchymal stem cells (UC-MSC) are promising candidates for wound healing. However, the low amplification efficiency of MSC in vitro and their low survival rates after transplantation have limited their medical application. In this study, we fabricated a micronized amniotic membrane (mAM) as a microcarrier to amplify MSC in vitro and used mAM and MSC (mAM-MSC) complexes to repair burn wounds. Results showed that MSC could live and proliferate on mAM in a 3D culture system, exhibiting higher cell activity than in 2D culture. Transcriptome sequencing of MSC showed that the expression of growth factor-related, angiogenesis-related, and wound healing-related genes was significantly upregulated in mAM-MSC compared to traditional 2D-cultured MSC, which was verified via RT-qPCR. Gene ontology (GO) analysis of differentially expressed genes (DEGs) showed significant enrichment of terms related to cell proliferation, angiogenesis, cytokine activity, and wound healing in mAM-MSC. In a burn wound model of C57BL/6J mice, topical application of mAM-MSC significantly accelerated wound healing compared to MSC injection alone and was accompanied by longer survival of MSC and greater neovascularization in the wound.

Zwitterionic Polysaccharide-Based Hydrogel Dressing as a Stem Cell Carrier to Accelerate Burn Wound Healing

Stem cell therapy integrated with hydrogels has shown promising potential in wound healing. However, the existing hydrogels usually cannot reach the desired therapeutic efficacy for burn wounds due to the inadaptability to wound shape and weak anti-infection ability. Moreover, it is difficult to improve the environment for the survival and function of stem cells under complicated wound microenvironments. In this study, an injectable and self-healing hydrogel (DSC), comprising sulfobetaine-derived dextran and carboxymethyl chitosan, is fabricated through a Schiff-base reaction. Meanwhile, the DSC hydrogel shows high nonfouling properties, including resistance to bacteria and nonspecific proteins; moreover, the prepared hydrogel can provide a biomimetic microenvironment for cell proliferation whilst maintaining the stemness of adipose-derived stem cells (ADSCs) regardless of complex microenvironments. In burnt murine animal models, the ADSCs-laden hydrogel can significantly accelerate wound healing rate and scarless skin tissue regeneration through multiple pathways. Specifically, the ADSCs-laden DSC hydrogel can avoid immune system recognition and activation and thus reduce the inflammatory response. Moreover, the ADSCs-laden DSC hydrogel can promote collagen deposition, angiogenesis, and enhance macrophage M2 polarization in the wound area. In summary, sulfobetaine-derived polysaccharide hydrogel can serve as a versatile platform for stem cell delivery to promote burn wound healing.

Enzymatic Debridement of Deep Thermal Burns in the Russian Federation: First Experience

Since its approval in Europe a decade ago, NexoBrid^® enzymatic debridement of deep thermal burns has been gaining acceptance as standard practice around the world. The purpose of this study is to report the first experience with NexoBrid^® in the Russian Federation. During 2019-2020, we conducted a post-registration clinical study assessing the safety and treatment results of NexoBrid^® enzymatic debridement. The study involved 15 adult patients suffering from deep thermal burns over an area ≤15% of their total body surface area. Patients were treated with NexoBrid^® within 3 days of injury, followed by spontaneous or surgical wound closure. Complete eschar removal was achieved in twelve patients, 80% eschar removal in two patients, and 70% in one patient. Complete spontaneous epithelialization of wounds was achieved in 12 patients (80%) within 18 ± 1.9 days after the start of treatment. We did not witness pathological scarring during follow-up, and there were no significant safety issues throughout the study. Early use of NexoBrid^® resulted in rapid, effective, and safe eschar removal with good results and sufficient preservation of viable dermis to allow for spontaneous healing in 80% of patients. These results demonstrate the ability to minimize surgical intervention and hopefully lead to better long-term scarring results.

Gelatin Microspheres Loaded with Wharton's Jelly Mesenchymal Stem Cells Promote Acute Full-Thickness Skin Wound Healing and Regeneration in Mice

Objective: At present, there is an urgent need to develop a novel and practical therapeutic approach to accelerate the healing of acute wounds. Mesenchymal stem cell (MSC)-based therapy is emerging as a promising therapeutic approach for acute skin wounds. However, there are still challenges in clinical application of this strategy, such as low survivability, low retention time, and less engraftment in skin wounds. Approach: Wharton's jelly mesenchymal stem cells (WJMSCs) were seeded into three-dimensional (3D) gelatin microspheres (GMs) to identify the biocompatibility of GMs. WJMSCs were embedded in GMs and then encapsulated with Pluronic F-127 (PF-127) and sodium ascorbyl phosphate (SAP) combination to transplant onto acute full-thickness skin wound in mice. Histology, immunohistochemistry, and immunofluorescence assay were used to investigate the skin wound healing, dermis regeneration, collagen deposition, cell proliferation, and neovascularization. Results: Three-dimensional GM had strong biocompatibility, compared with two-dimensional adherent culturing, GM loading increased the cell viability and proliferation ability of WJMSCs. WJMSCs+GM+PF-127+SAP transplantation increased skin wound healing rate, dermis regeneration, and type III collagen deposition through improving macrophage polarization, cell proliferation, neovascularization, cell retention, and engraftment at skin wound site. Innovation: The effective 3D encapsulation technology for WJMSCs solved the main problems of cell activity and residence time during MSC transplantation. WJMSCs+GM+PF-127+SAP transplantation will be a new and effective MSC biomaterials-based therapeutic strategy for acute skin traumatic wounds. Conclusion: WJMSCs+GM+PF-127+SAP transplantation facilitated acute full-thickness skin wound healing and regeneration and might be a new and effective therapy for acute skin traumatic wounds.

Enhancing the accuracy of surgical wound excision following burns trauma via application of Rapid Evaporative IonisationMass Spectrometry (REIMS)

BACKGROUND

Surgical wound excision is a necessary procedure for burn patients that require the removal of eschar. The extent of excision is currently guided by clinical judgement, with excessinto healthy tissue potentially leading to excessive scar, or inadequate debridement increasing risk of infection. Thus, an objective real-time measure to facilitate accurate excision could support clinical judgement and improve this surgical procedure. This study was designed to investigate the potential use of Rapid evaporative ionisation mass spectrometry (REIMS) as a tool to support data-driven objective tissue excision.

METHODS

Data were acquired using a multi-platform approach that consisted of both Rapid Evaporative Ionisation Mass Spectrometry (REIMS) performed on intact skin, and comprehensive liquid chromatography-mass spectrometry (LC-MS/MS) lipidomics performed on homogenised skin tissue extracts. Data were analysed using principal components analysis (PCA) and multivariate orthogonal projections to latent squares discriminant analysis (OPLS-DA) and logistic regression to determine the predictability of the models.

RESULTS

PCA and OPLS-DA models of the REIMS and LC-MS/MS lipidomics data reported separation of excised and healthy tissue. Molecular fingerprints generated from REIMS analysis of healthy skin tissue revealed a high degree of heterogeneity, however, intra-individual variance was smaller than inter-individual variance. Both platforms indicated high levels of skin classification accuracy. In addition, OPLS-DA of the LC-MS/MS lipidomic data revealed significant differences in specific lipid classes between healthy control and excised skin samples; including lower free fatty acids (FFA), monoacylglycerols (MAG), lysophosphatidylglycerol (LPG) and lysophosphatidylethanolamines (LPE) in excised tissue and higher lactosylceramides (LCER) and cholesterol esters (CE) compared to healthy control tissue.

CONCLUSIONS

Having established the heterogeneity in the biochemical composition of healthy skin using REIMS and LC-MS/MS, our data show that REIMS has the potential to distinguish between excied and healthy skin tissue samples. This pilot study suggests that REIMS may be an effective tool to support accurate tissue excision during burn surgery.

Use of Composite Acellular Dermal Matrix-Ultrathin Split-Thickness Skin in Hand Hot-Crush Injuries: A One-Step Grafting Procedure

Background

Hot-crush injuries to the hands can be devastating, and early debridement and coverage with skin autograft remains the golden standard of wound treatment. However, this type of treatment is not feasible or unlikely to succeed due to limited donor sites and wound characteristics of hot-crush injuries on hands. Thus, the composite grafting of acellular dermal matrix (ADM) and split-thickness skin graft (STSG) as a novel alternative method has been attempted. In this series, the results are presented to demonstrate the feasibility and effectiveness of the use of one-stage procedure for early reconstruction in hand hot-crush injuries.

Methods

All consecutive patients with hand hot-crush injuries, who underwent one-stage procedure of ADM and ultrathin STSG for soft tissue coverage at our institution from December 2018 to November 2019, were retrospectively analyzed. Wound dressings were opened on 7 days after operation to examine graft survival and complications. Patients were followed up for at least 9 months to evaluate their hand profiles.

Results

Samples of 14 patients with a total of 23 wounds were involved in the study. Thirteen of the 23 third–fourth-degree wounds had varying degrees of tendon exposure. On 7 days postoperation, the composite grafts survived in 12 patients with minimal focal graft losses and liquefaction and necrosis in 2 patients, which achieved successful healing following new coverage of ultrathin STSG. All the wounds healed with hospital stays ranging from 9 days to 32 days (median: 24.5 days). At the final follow-up (from 9 months to 20 months), all patients achieved excellent or good total active motion grade and good scar quality (Vancouver scar scale scored 1–3) with no revision surgery.

Conclusions

One-stage composite grafting of ADM and ultrathin STSG is a reliable alternative for early reconstruction in hand hot-crush injuries, which delivers good functional outcomes and a good cosmetic appearance.

Enzymatic debridement: past, present, and future

INTRODUCTION

Early surgical debridement of the deep second and third-degree burns is still the standard of care (SOC) to prepare the wound bed for skin grafting. However, this technique has some drawbacks that explain the growing interest in enzymatic debridement as an alternative. In this article, we provide a historic overview as well as the current state-of-the-art and future prospective of this type of non-surgical debridement.

MATERIALS AND METHODS

A narrative review of the available literature was conducted using a systematic search.

RESULTS

A total of 32 articles were included. The only enzyme mixture still used nowadays for burn eschar removal is bromelain-based. There is increasing evidence that this type of enzymatic debridement is a powerful tool to selectively remove the eschar in deep burns, thereby reducing the need for autologous skin grafting compared to surgical SOC. Moreover, off-label use of enzymatic debridement with NexoBrid^® (facial, pediatric, and >15%TBSA burns) has proven to be effective and safe.

CONCLUSION

There is increasing evidence that bedside administered NexoBrid^®, preferably under regional anesthesia, is a powerful tool for selective burn eschar removal. However, the clinical wound bed evaluation post-NexoBrid^® procedure in relation to the optimal treatment decision-conservative treatment vs. surgery-is not yet completely elucidated. More high-quality prospective clinical trials are necessary to compare enzymatic debridement of objectively confirmed deep burns with the current standard treatment and assess the effectiveness of the eschar removal, the need for surgery, the healing time of such wounds, and the long-term scar quality.

A modified burn comb model with a new dorsal frame that allows for local treatment in partial-thickness burns in rats

Burn wound progression (BWP) leads to vertical and horizontal injury extension. The "burn comb model" is commonly used, in which a full-thickness burn with intercalated unburned interspaces is induced. We aimed to establish an injury progressing to the intermediate dermis, allowing repeated wound evaluation. Furthermore, we present a new dorsal frame that enables topical drug application. 8 burn field and 6 interspaces were induced on each of 17 rats' dorsa with a 10-second burn comb application. A developed 8-panel aluminum frame was sutured onto 12 animals and combined with an Elizabethan collar. Over 14 days, macroscopic & histologic wound assessment and Laser-Speckle-Contrast-Imaging (LSCI) were performed besides evaluation of frame durability. The 10-second group was compared to 9 animals injured with a full-thickness 60-second model. Frame durability was sufficient up to day 4 with 8 of 12 frames (67%) still mounted. The 60-second burn led to an increased extent of interspace necrosis (p=0.002). The extent of necrosis increased between days 1 and 2 (p=0.001), following the 10-second burn (24%±SEM 8% to 40%±SEM 6%) and the 60-second burn (57%±SEM 6% to 76%±SEM 4%). Interspace LSCI perfusion was higher than burn field perfusion. It earlier reached baseline levels in the 10-second group (on day 1: 142%±SEM 9% vs. 60%±SEM 5%; p<0.001). Within day 1, the 10-second burn showed histological progression to the intermediate dermis, both in interspaces and burn fields. This burn comb model with its newly developed fixed dorsal frame allows investigation of topical agents to treat BWP in partial-thickness burns.

Early experiences using bromelain-based enzymatic debridement in a tertiary burns centre in the United Kingdom: A retrospective case series review

BACKGROUND

The modern ethos of burn care requires a holistic approach that helps patients to not only survive but also maintain a good quality of life. Bromelain-based enzymatic debridement with Nexobrid™ (NXB) has been shown to selectively debride burnt tissue and allow dermal preservation, which has the potential to reduce surgical burden and improve scarring. In this study, early experience with the use of Nexobrid™ at a tertiary burns centre between July 2016 and December 2019 is presented. In particular, the study assessed whether NXB had changed the acute care delivered to this cohort.

METHODS

A retrospective analysis of the patients' records was performed. Results were analysed and presented in the context of current literature.

RESULTS

Twenty adult patients (17 male, 3 female) underwent enzymatic debridement with NXB. Median age was 42.5 years. Mean total burn surface area (TBSA) on admission was 20%. Twelve patients were admitted to the intensive care unit, and eight were admitted to the adult burns ward. Mean TBSA treated with NXB was 8.2%, usually within 24 h of admission (mean). All patients had anaesthetist-led analgesia. NXB debridement was successful in 55% of patients, obviating the need for escharotomy in some patients. Sixty percent of all patients required further surgery, and 80% of facial burns treated with NXB required further surgery. Inotrope support was associated with NXB failure (p = 0.015). Mean length of stay was 29 days.

DISCUSSION

Current evidence, including our own findings, cannot justify replacing the current surgical standard of care with NXB, but it certainly solidifies enzymatic debridement as a useful adjunct that should form part of the modern burn surgeon's armamentarium.

Hydrosurgical debridement versus conventional surgical debridement for acute partial-thickness burns

BACKGROUND

Burn injuries are the fourth most common traumatic injury, causing an estimated 180,000 deaths annually worldwide. Superficial burns can be managed with dressings alone, but deeper burns or those that fail to heal promptly are usually treated surgically. Acute burns surgery aims to debride burnt skin until healthy tissue is reached, at which point skin grafts or temporising dressings are applied. Conventional debridement is performed with an angled blade, tangentially shaving burned tissue until healthy tissue is encountered. Hydrosurgery, an alternative to conventional blade debridement, simultaneously debrides, irrigates, and removes tissue with the aim of minimising damage to uninjured tissue. Despite the increasing use of hydrosurgery, its efficacy and the risk of adverse events following surgery for burns is unclear.

OBJECTIVES

To assess the effects of hydrosurgical debridement and skin grafting versus conventional surgical debridement and skin grafting for the treatment of acute partial-thickness burns.

SEARCH METHODS

In December 2019 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 for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that enrolled people of any age with acute partial-thickness burn injury and assessed the use of hydrosurgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, 'Risk of bias' assessment, and GRADE assessment of the certainty of the evidence.

MAIN RESULTS

One RCT met the inclusion criteria of this review. The study sample size was 61 paediatric participants with acute partial-thickness burns of 3% to 4% total burn surface area. Participants were randomised to hydrosurgery or conventional debridement. There may be little or no difference in mean time to complete healing (mean difference (MD) 0.00 days, 95% confidence interval (CI) -6.25 to 6.25) or postoperative infection risk (risk ratio 1.33, 95% CI 0.57 to 3.11). These results are based on very low-certainty evidence, which was downgraded twice for risk of bias, once for indirectness, and once for imprecision. There may be little or no difference in operative time between hydrosurgery and conventional debridement (MD 0.2 minutes, 95% CI -12.2 to 12.6); again, the certainty of the evidence is very low, downgraded once for risk of bias, once for indirectness, and once for imprecision. There may be little or no difference in scar outcomes at six months. Health-related quality of life, resource use, and other adverse outcomes were not reported.

AUTHORS' CONCLUSIONS

This review contains one randomised trial of hydrosurgery versus conventional debridement in a paediatric population with low percentage of total body surface area burn injuries. Based on the available trial data, there may be little or no difference between hydrosurgery and conventional debridement in terms of time to complete healing, postoperative infection, operative time, and scar outcomes at six months. These results are based on very low-certainty evidence. Further research evaluating these outcomes as well as health-related quality of life, resource use, and other adverse event outcomes is required.

Development of nursing care guideline for burned hands

Aim

To develop an evidence-based guideline to care for hand-burned patients.

Design

An integrative review.

Method

The search was conducted of EMBASE, PubMed, Web of Science, SCOPUS, Clinical Key, Iranmedex, Magiran, Scientific Information Database (SID), Cochran, CINAHL and Google Scholar databases from January 2000-August 2019. Following the formation of the research team, two researchers independently selected the eligible studies. The initial search resulted in 2,230 records; ultimately, 40 articles were identified to be the review after screening the records based on the study's inclusion and exclusion criteria. Quality of selected studies was evaluated with the MMAT method.

Results

Data syntheses of selected studies, coded by highlighting the relevant parts of the text, and assigning code words to these areas were done. Following this, a constant comparison was used to develop categories by combining codes. Finally, hand burns nursing care guideline was developed by categorizing descriptive themes in two main phases.

Conclusion

This review results have shown that evidence-based guidelines present high-quality recommendations for the healthcare team, which improves the quality of clinical care. Due to a lack of established guidelines in our context, it seems to be helpful to use evidence-based guidelines in managing burned hands.

Effective enzymatic debridement of burn wounds depends on the denaturation status of collagen

The treatment of burn wounds by enzymatic debridement using bromelain has shown promising results in our burn center. However, inadequate debridement occurred in a few cases in which the etiology of the burn was attributed to relatively low temperature burns. We hypothesized that bromelain is ineffective in burns in which collagen denaturation, which occurs approximately at 65°C, has not taken place. Our objective was to assess whether there is a relationship between the denaturation of collagen and the ability of bromelain to debride acute scald burn wounds of different temperatures. Ex vivo human skin from four different donors was cut into 1x1 cm samples, and scald burns were produced by immersion in water at temperatures of 40°C, 50°C, 60°C, 70°C, and 100°C for 20 minutes. Denaturation of collagen was assessed with histology, using hematoxylin and eosin (H&E) staining and a fluorescently labeled collagen hybridizing peptide (CHP), and with second harmonic generation (SHG) microscopy. Burned samples and one control sample (room temperature) were weighed before and after application of enzymatic debridement to assess the efficacy of enzymatic debridement. After enzymatic debridement, a weight reduction of 80% was seen in the samples heated to 70°C and 100°C, whereas the other samples showed a reduction of 20%. Unfolding of collagen, loss of basket-weave arrangement, and necrosis was seen in samples heated to 60°C or higher. Evident CHP fluorescence, indicative of collagen denaturation, was seen in samples of 60°C, 70°C and 100°C. SHG intensity, signifying intact collagen, was significantly lower in the 70°C and 100°C group (P <.05) compared to the lower temperatures. In conclusion, denaturation of collagen in skin samples occurred between 60°C and 70°C and strongly correlated with the efficacy of enzymatic debridement. Therefore, enzymatic debridement with the use of bromelain is ineffective in scald burns lower than 60°C.

PF-127 hydrogel plus sodium ascorbyl phosphate improves Wharton's jelly mesenchymal stem cell-mediated skin wound healing in mice

Background

Factors such as poor engraftment, retention, and survival of the transplanted stem cells are deemed to limit their therapeutic efficacy for wound regeneration. Hence, it is necessary to explore these issues in order to resolve them. In this study, we aim to investigate the role of Pluronic F-127 (PF-127) hydrogel plus antioxidant sodium ascorbyl phosphate (SAP) in enhancing Wharton’s jelly mesenchymal stem cell (WJMSC)-mediated effectiveness on full-thickness skin wound healing in mice.

Methods

First, the cytotoxicity of PF-127 and the biological effect of SAP on the survival of WJMSCs were tested in vitro using cell viability and proliferation assays. Next, a cell suspension containing WJMSCs, PF-127, and SAP was topically administered onto an 8-mm diameter excisional full-thickness wound bed. Eight days after transplantation, the mice were sacrificed and the skin tissue was excised for histological and immunohistochemical analysis. Finally, in vivo distribution of transplanted WJMSCs was traced to investigate cell engraftment and the potential therapeutic mechanism.

Results

PF-127 was found to be cytotoxic to WJMSCs while SAP significantly improved the survival of PF-127-embedded WJMSCs. When this combination was topically transplanted onto the wound bed, wound healing was facilitated and dermis regeneration was achieved on the 8th day after surgery, as evidenced by an increase in dermal thickness, newly developed hair follicles, and collagen fiber deposition accompanied by a reduction in scar width. Further, immunohistochemical analysis demonstrated a higher number of anti-inflammatory M2 macrophages, proliferating cells, and newly formed blood vessels in the WJMSCs/PF-127/SAP group relative to all other groups. In addition, in vivo tracking results revealed a highly enhanced engraftment of WJMSCs accumulated in the dermis in the WJMSCs/PF-127/SAP group.

Conclusions

SAP significantly improves the survival of WJMSCs in PF-127 encapsulation. Further, PF-127 plus SAP is an effective combination that enhances WJMSC engraftment in the dermis, which then promotes full-thickness wound healing through potential M2 macrophage formation and angiogenesis.