Porcine Xenograft and Epidermal Fully Synthetic Skin Substitutes in the Treatment of Partial-Thickness Burns: A Literature Review

Comparison of the effectiveness of three different skin substitutes for the treatment of pediatric burns

Early debridement of partial-thickness burns and coverage with skin substitutes is currently the standard of care in children, although there is currently no "gold standard" skin substitute. Our aim is to compare the effectiveness of three different skin substitutes, analyzing the medium- and long-term outcomes.

METHODS

A retrospective study was conducted on burn patients under 18 years admitted to our Burn Unit between 2015 and 2021, who were divided into 3 groups according to the type of skin substitute used (EZ-derm®, Biobrane®, and Suprathel®). Demographic and clinical data and short- and long-term outcomes were analyzed. Effectiveness was analyzed by escharectomy and grafting rate during acute management and long-term follow-up reintervention rate. A total of 378 patients were included (179 EZ-derm® group, 107 Biobrane® group, and 92 Suprathel® group). No differences in demographics or burn characteristics were observed between the groups. Patients treated with Suprathel® had a significantly shorter hospital stay (median 4 days (IQR 2-9)), a lower rate of escharectomy and grafting during acute management (21.1%), and a lower long-term follow-up reintervention rate (18.5%) when compared to the EZ-derm® group (median stay 9 days (IQR 6-13); escharectomy and graft 24.6% and reintervention 26.8%) and to the Biobrane® group (median stay 9 days (IQR 7-14); escharectomy and graft 32.1% and reintervention 26.2%).

CONCLUSION

Treatment of partial-thickness burns with Suprathel® is associated with a shorter hospital stay, lower need for escharectomy and grafting, and lower need for long-term reintervention. Therefore, it should be considered the treatment of choice for pediatric partial-thickness burns.

WHAT IS KNOWN

• Different types of skin substitutes are available for the treatment of skin burns in paediatric patients.

WHAT IS NEW

• Suprathel® is linked to a reduction in hospital stays, a lower need for escharectomy and grafting, and a lower likelihood of requiring long-term re-interventions.

COMPARATIVE STUDY OF STRIPED CATFISH (PANGASIUS HYPOPHTHALMUS) SKIN, NILE TILAPIA (OREOCHROMIS NILOTICUS) SKIN, AND PORCINE SKIN AS A XENOGRAFT MATERIAL FOR BURN WOUND

Burn injury remains a health problem, specifically in Indonesia. In major burns, xenograft has been proved to be useful as temporary wound coverage. However, some xenografts are not widely available due to cultural, financial and religious backgrounds, or have an unesthetic appearance, such as the scaly appearance of tilapia fish xenograft. Striped catfish (Pangasius hypophthalmus) is a scaleless fish that has abundant type 1 collagen. This study aimed to compare striped catfish skin to commonly used xenograft (Nile tilapia and porcine skin) as xenograft material for burn wound. In this experimental study, nine different skin samples of striped catfish, Nile tilapia and porcine were prepared and histologically examined using hematoxylin-eosin stained samples. Macroscopic and microscopic features of each sample were documented and analysed. The macroscopic skin appearances of striped catfish were hairless and scaleless with black-silver color and moderate thickness. As for microscopic features, the epidermal thickness of striped catfish skin (8.49±1.60 μm) was significantly different to both Nile tilapia (2.18±0.37 μm; p<0.001) and porcine skin (42.22±14.85 μm; p=0.002). The dermal thickness of striped catfish skin (288.46±119.04 μm) was similar to Nile tilapia (210.68±46.62 μm; p=0.783) but differs significantly to porcine skin (1708.44±505.12 μm; p<0.001). The integrity and collagen organization of striped catfish was also similar to tilapia based on semi-quantitative histology scoring system (p>0.05). Striped catfish had potential macroscopic appearance and comparable microscopic features to Nile tilapia; smoother macroscopic appearance, thicker epidermis, and similar dermis thickness. Therefore, we believe it can be potentially used as a xenograft material. Further studies are required to evaluate the effectiveness and feasibility of striped catfish xenograft in burn wound management.

Integrating dermal substitutes in soft tissue repair: Insights from a case series and comprehensive literature review

The use of dermal substitutes with subsequent skin graft application constitutes an alternative treatment option in situations that limit the use of other conventional approaches.

Exploring an innovative decellularization protocol for porcine nerve grafts: a translational approach to peripheral nerve repair

Introduction

Peripheral nerves are frequently affected by lesions caused by traumatic or iatrogenic damages, resulting in loss of motor and sensory function, crucial in orthopedic outcomes and with a significant impact on patients' quality of life. Many strategies have been proposed over years to repair nerve injuries with substance loss, to achieve musculoskeletal reinnervation and functional recovery. Allograft have been tested as an alternative to the gold standard, the autograft technique, but nerves from donors frequently cause immunogenic response. For this reason, several studies are focusing to find the best way to decellularize nerves preserving either the extracellular matrix, either the basal lamina, as the key elements used by Schwann cells and axons during the regenerative process.

Methods

This study focuses on a novel decellularization protocol for porcine nerves, aimed at reducing immunogenicity while preserving essential elements like the extracellular matrix and basal lamina, vital for nerve regeneration. To investigate the efficacy of the decellularization protocol to remove immunogenic cellular components of the nerve tissue and to preserve the basal lamina and extracellular matrix, morphological analysis was performed through Masson's Trichrome staining, immunofluorescence, high resolution light microscopy and transmission electron microscopy. Decellularized porcine nerve graft were then employed in vivo to repair a rat median nerve lesion. Morphological analysis was also used to study the ability of the porcine decellularized graft to support the nerve regeneration.

Results and Discussion

The decellularization method was effective in preparing porcine superficial peroneal nerves for grafting as evidenced by the removal of immunogenic components and preservation of the ECM. Morphological analysis demonstrated that four weeks after injury, regenerating fibers colonized the graft suggesting a promising use to repair severe nerve lesions. The idea of using a porcine nerve graft arises from a translational perspective. This approach offers a promising direction in the orthopedic field for nerve repair, especially in severe cases where conventional methods are limited.

New strategies for sterilization and preservation of fresh fish skin grafts

The introduction of fish skin as a biological dressing for treating burns and wounds holds great promise, offering an alternative to existing management strategies. However, the risk of disease transmission is a significant concern. Therefore, this study aimed to examine how established sterilization and preservation procedures affected fish skin grafts' microbiological and histological properties for long-term usage. Lyophilization of the fish skin graft followed by rehydration in normal saline for 15 min did not change the collagen content. Furthermore, gamma irradiation of the lyophilized fish skin graft at different lengths 5, 10, and 25 KGy showed a significant reduction in microbial growth (aerobic bacteria, aerobic yeasts, and fungi) at 15- and 30 days after the irradiation. However, exposure to 10 KGy was found to be the most effective intensity among the different gamma irradiation lengths since it preserved the collagen fiber content and intensity in the lyophilized fish skin grafts at 15- and 30 days after the irradiation. These findings provide efficient preservation and sterilization methods for long-term usage of the fresh Tilapia skin grafts used for biological dressings.

Alloplastic Epidermal Skin Substitute in the Treatment of Burns

The goal of burn wound treatment is to ensure rapid epithelialization in superficial burns and the process of rebuilding the lost skin in deep burns. Topical treatment plays an important role. One of the innovations in the field of synthetic materials dedicated to the treatment of burns is epidermal skin substitutes. Since the introduction of Suprathel®, the alloplastic epidermal substitute, many research results have been published in which the authors investigated the properties and use of this substitute in the treatment of wounds of various origins, including burn wounds. Burn wounds cause both physical and psychological discomfort, which is why ensuring comfort during treatment is extremely important. Alloplastic epidermal substitute, due to its biodegradability, plasticity, no need to remove the dressing until healing, and the associated reduction in pain, is an alternative for treating burns, especially in children.

Alginate and Nanocellulose Dressings With Extract From Salmon Roe Reduce Inflammation and Accelerate Healing of Porcine Burn Wounds

Partial-thickness thermal burn wounds are characterized by a prolonged inflammatory response, oxidative stress, tissue damage, and secondary necrosis. An optimal dressing for burn wounds would reduce inflammation and oxidative stress while providing a moist, absorbent, and protective cover. We have developed an extract from unfertilized salmon roe containing components with potential anti-inflammatory and antioxidative properties, called HTX. HTX has been combined with alginate from brown algae and nanocellulose from tunicates, and 3D printed into a solid hydrogel wound dressing called Collex. Here, Collex was tested on partial thickness burn wounds in Göttingen minipigs compared to Jelonet, and a variant of Collex without HTX. We found that dermal treatment of burn wounds with Collex resulted in accelerated healing at a majority of measured points over 23 days, compared to treatment with Jelonet. In comparison to Collex without HTX, Collex enhanced healing in the first week after trauma where wound progression was pronounced. Notably, Collex reduced the inflammatory response in the early post-injury phase. The anti-inflammatory response of Collex was investigated in more detail on activated M1 macrophages. We found that Collex, as well as HTX alone, significantly reduced the secretion of pro-inflammatory interleukin-1β as well as intracellular levels of oxidative stress. The results from this study indicate that Collex is a potent dressing for the treatment of burn wounds, with the anti-inflammatory effect of HTX beneficial in the initial phase, and the moist qualities of the hydrogel favorable both in the initial and the proceeding proliferative phase of wound healing.

Xeroform Gauze Bolster: A Cost-Effective Alternative to Synthetic Skin Grafts

This case presentation describes and justifies the use of petrolatum gauze that is impregnated with 3% bismuth tribromophenate (Xeroform) as a low-cost and effective alternative for synthetic skin grafts. Herein, we discuss clinical trials that demonstrate the benefits of utilizing Xeroform for second-intention healing as well as photographs of a case in which the authors used this method and followed a patient's wound-healing process over time.

The Burn Wound

Skin serves as a protective barrier against infection, prevents excessive fluid and electrolyte losses, performs crucial thermoregulation, and provides tactile feedback of surroundings. The skin also plays an essential role in human perception of body image, personal appearance, and self-confidence. With these many diverse functions, understanding normal anatomic composition of skin is pivotal to evaluating the extent of its disruption from burn injury. This article discusses the pathophysiology, initial evaluation, subsequent progression, and healing of burn wounds. By delineating the various microcellular and macrocellular alterations of burn injury, this review also augments providers' capacity to deliver patient-centered, evidence-based burn care.

Current state of clinical trials on xenograft

BACKGROUND

Xenotransplantation is a worth investing branch of science, since it aims to fulfil the demand on human cells, tissues and organs. Despite decades of consistent work in preclinical assessments, clinical trials on xenotransplantation are far from reaching the targeted goal. Our study aims to track the characteristics, assess the content and summarize the plan of each trial on skin, beta-island, bone marrow, aortic valve and kidney xenografts, leading to a clear sorting of efforts made in this field.

METHODS

In December 2022, we searched clinicaltrial.gov for interventional clinical trials related to xenograft of skin, pancreas, bone marrow, aortic valve and kidney. A total of 14 clinical trials are included in this study. Characteristics on each trial were gathered. Linked publications were searched using Medline/PubMed and Embase/Scopus. Content of trials was reviewed and summarized.

RESULTS

Only 14 clinical trials met our study's criteria. The majority were completed, and most of the trials' enrolment was between 11 and 50 participants. Nine trials used a xenograft of porcine origin. Six trials targeted skin xenotransplantation, four targeted β-cells, two targeted bone marrow and one trial targeted each of the kidney and aortic valve. The average length of trials was 3.38 years. Four trials were conducted in the United States and two trials in each of Brazil, Argentina and Sweden. Of all the included trials, none had any results provided and only three had published work. Phases I, III, and IV had only one trial each. A total of 501 participants were enrolled in these trials.

CONCLUSION

This study sheds the light on the current state of clinical trials on xenograft. Characteristically, trials on this field are of low number, low enrolment, short duration, few related publications and no published results. Porcine organs are the most used in these trials, and skin is the most studied organ. An extension of the literature is highly needed due to the variety of conflicts mentioned. Overall, this study sheds the light on the necessity of managing research efforts, leading to the initiation of more trials targeting the field of xenotransplantation.

Comparing the application of various engineered xenografts for skin defects: A systematic review

INTRODUCTION

Xenografts are a now a cornerstone in the management of wound dressings. Promising results were achieved since 1960 in the application of skin substitute for skin defects.

OBJECTIVE

The objective of this study was to evaluate the efficacy of various xenografts.

METHODS

A literature research was conducted using the following query: 'Porcine skin dermatology substitute', 'bovine skin dermatology substitute', 'xenograft skin substitute dermatology', 'xenografts skin defect', 'porcine skin defect', 'bovine skin defect'.

RESULTS

The review yielded 35 articles pertaining to the topic. Main indications for porcine and bovine xenograft application were burn wounds and post-traumatic wounds, respectively. Mean discharge date or length of stay was at the 6th day after porcine application, and the time of graft healing was reported for 33.7% (n = 510) of patients. Promising results were seen with Matriderm and split-thickness skin graft. Most wounds achieved an excellent cosmetic result with full range of motion and a smooth contour appearance. A great variety of tissue substitutes exist, and the choice of graft application should depend on a patient's factors, product availability, wound type, size, and physician's factors.

CONCLUSION

In summary, xenografts are more economic and affordable but have higher risk of infections compared to allografts.

Imaging and Characterization of Oxidative Protein Modifications in Skin

Skin plays an important role in protection, metabolism, thermoregulation, sensation, and excretion whilst being consistently exposed to environmental aggression, including biotic and abiotic stresses. During the generation of oxidative stress in the skin, the epidermal and dermal cells are generally regarded as the most affected regions. The participation of reactive oxygen species (ROS) as a result of environmental fluctuations has been experimentally proven by several researchers and is well known to contribute to ultra-weak photon emission via the oxidation of biomolecules (lipids, proteins, and nucleic acids). More recently, ultra-weak photon emission detection techniques have been introduced to investigate the conditions of oxidative stress in various living systems in in vivo, ex vivo and in vitro studies. Research into two-dimensional photon imaging is drawing growing attention because of its application as a non-invasive tool. We monitored spontaneous and stress-induced ultra-weak photon emission under the exogenous application of a Fenton reagent. The results showed a marked difference in the ultra-weak photon emission. Overall, these results suggest that triplet carbonyl (³C=O^∗) and singlet oxygen (¹O₂) are the final emitters. Furthermore, the formation of oxidatively modified protein adducts and protein carbonyl formation upon treatment with hydrogen peroxide (H₂O₂) were observed using an immunoblotting assay. The results from this study broaden our understanding of the mechanism of the generation of ROS in skin layers and the formation/contribution of various excited species can be used as tools to determine the physiological state of the organism.

Comparison of Long-Term Skin Quality and Scar Formation in Partial-Thickness Burn Wounds Treated with Suprathel® and epicitehydro® Wound Dressings

Background and Objectives: Scar formation after burn trauma has a significant impact on the quality of life of burn patients. Hypertrophic scars or keloids can be very distressing to patients due to potential pain, functional limitations, or hyper- or hypopigmentation. In a previous study comparing Suprathel® and the new and cheaper dressing epicitehydro®, we were able to show that pain reduction, exudation, and time until wound-healing of partial-thickness burn wounds were similar, without any documented infections. No study exists that objectively measures and compares skin and scar quality after treatment with Suprathel® and epicitehydro® at present. Materials and Methods: In this study, the scar quality of 20 patients who had been treated with Suprathel® and epicitehydro® was objectively assessed using the Cutometer®, Mexameter®, and Tewameter®, as well as subjectively with the Patient and Observer Scar Assessment Scale, 3, 6, and 12 months after burn injury. Results: In all performed measurements, no significant differences were detected in scar formation after treatment of partial-thickness burn wounds with the two dressings. Conclusions: Both the newer and less expensive wound-dressing epicitehydro® and the well-known wound-dressing Suprathel® resulted in stable wound closure and showed good cosmetic results in the follow-up examinations.

Therapeutic Treatment of 2A Grade Burns with Decellularized Bovine Peritoneum as a Xenograft: Multicenter Randomized Clinical Trial

Background and Objectives: Homogeneous and xenogenic bioengineering structures are actively used as wound coatings in treatment of burns and have already shown their effectiveness. Nevertheless, the disadvantage of such dressings is their high cost. This issue is particularly challenging for developing countries in which the incidence of burns is the highest one. With such needs taken into account, the research team developed and clinically tested a new wound coating based on decellularized bovine peritoneum (DBP). Materials and Methods: A multicenter randomized clinical trial was conducted to evaluate DBP. The following variables were considered in the research study: the number of inpatient days, the number of dressing changes, the level of pain experienced during dressing changes, and the condition of wounds at the time of the follow-up examination. Results: The research involved 68 participants. It was found that the patients who were treated with a DBP experienced less pain with less changes of dressings. However, the number of inpatient days and wound healing failed to demonstrate statistically significant difference compared to the control group. Conclusions: In the given research, DBP showed efficacy in improving patients' quality of life by reducing pain and the number of dressings' changes. However, when comparing this research study with the studies of other animal-derived wound coverings, there were a number of differences and limitations in the parameters. Thus, the results requires further study for a greater comparability of data. Given the above, we expect that DBP will become an inexpensive and effective treatment for burns in developing countries.

Skin regeneration, repair, and reconstruction: present and future

Background

Large skin defects caused by trauma (e.g., burns) or due to other reasons (e.g., tumor-related skin resections) require sufficient skin replacement. The constant improvement of innovative methods of skin replacement and skin expansion mean that even burn victims with more than 80% body surface burned have a realistic chance of survival. Due to these new developments, not only has survival rate increased, but also quality of life has increased tremendously over the past decades.

Methods

The aim of this review is to present an overview of current standards and future trends concerning the treatment of skin defects. The main focus is placed on the most important technologies and future trends.

Results

Autologous skin grafting was developed more than 3500 years ago. Several approaches and techniques have been discovered and established in burn care and plastic surgery since then. Great achievements were made during the 19th and 20th centuries. Many of these old and new techniques are still part of modern burn and plastic surgery. Today, autologous skin grafting is still considered to be the gold standard for many wounds, but new technologies have been developed, ranging from biological to synthetic skin replacement materials.

Conclusion

Today, old and new technologies are available which allow us new treatment concepts. All this has led to the reconstructive clockwork for reconstructive surgery of the 21st century.

The Role of Skin Substitutes in Acute Burn and Reconstructive Burn Surgery: An Updated Comprehensive Review

Burns disrupt the protective skin barrier with consequent loss of cutaneous temperature regulation, infection prevention, evaporative losses, and other vital functions. Chronically, burns lead to scarring, contractures, pain, and impaired psychosocial well-being. Several skin substitutes are available and replace the skin and partially restore functional outcomes and improve cosmesis. We performed a literature review to update readers on biologic and synthetic skin substitutes to date applied in acute and reconstructive burn surgery. Improvement has been rapid in the development of skin substitutes in the last decade; however, no available skin substitute fulfills criteria as a perfect replacement for damaged skin.

Successful Treatment Outcomes for Partial Thickness Burns by Innovative Bovine Peritoneum Dressing

In the world practice of treating burns, acellular matrices have been used for quite a long time. However, the budget for treating one burn patient in Kazakhstan does not exceed $1000. This amount does not cover the costs for procurement of foreign-made xenograft dressings. Because the cattle breeding sector is very well-developed in the country, a domestic xenograft is produced by decellularization and sterilization of the cattle peritoneum, which costs only $10. This case report outlines how we used this matrix in a patient with partial thickness burns. A 45-year-old woman was admitted to the burn department with second stage burns on her back and right shoulder. The burn area comprised 10%, according to the Lund Browder chart. Once formal consent was obtained from the patient, an occlusive dressing was applied from the decellularized cattle peritoneum. Good adhesion of the dressing to the wound bed was noted. The patient was discharged from the hospital on the tenth day. It took 23 days to reach complete epithelialization. No adverse effects were noted. We believe that further studies conducted by our research team will allow this innovative, low-cost, easy-to-apply biologic dressing to be widely used in the therapeutic treatment of burns.

Use of Cultivated Epidermal Allograft in Chronic Wounds: A Novel Therapeutic Alternative

Introduction

Chronic wounds represent a frequent cause of consultation for plastic and reconstructive surgeons. The use of epidermal culture stands out because they provide complete epithelialization, adequate aesthetic-functional results, and no morbidity for the patient. Epifast® is a pre-manufactured cultured epidermal allograft derived from the amplification in vitro of human keratinocytes.

Materials and Methods

A prospective longitudinal multicenter study was carried out in four chronic wound reference centers, which were in charge of plastic and reconstructive surgery services. For a standardized wound bed preparation, the protocol synthesized by the acronym "TIME" was used. At the end of the "TIME" protocol, the pre-fabricated allograft was applied and removed 7 days after its application.

Results

A total of 133 patients with diagnosis of chronic wound were included in the study. The median age was 69.3 ± 13.6 years. The most common comorbidity found was diabetes mellitus type 2 in 71.4% of the patients (n = 95) and systemic arterial hypertension in 60.2% of the patients (n = 80). The most frequent location of chronic wounds was seen in the lower extremity with 45.1% (n = 60). The mean duration for it to close was 46 ± 14 days, in which they closed within the first 3 months in 93% (n = 125) of the cases. About 91.7% (n = 122) of the wounds achieved total closure.

Conclusion

Cultured epidermal allograft, combined with a meticulous technique and an adequate selection of patients, represents a safe and effective tool for chronic wounds.

Oxygen, pH, Lactate, and Metabolism-How Old Knowledge and New Insights Might Be Combined for New Wound Treatment

Over time, we have come to recognize a very complex network of physiological changes enabling wound healing. An immunological process enables the body to distinguish damaged cells and begin a cleaning mechanism by separating damaged proteins and cells with matrix metalloproteinases, a complement reaction, and free radicals. A wide variety of cell functions help to rebuild new tissue, dependent on energy provision and oxygen supply. Like in an optimized “bio-reactor,” disturbance can lead to prolonged healing. One of the earliest investigated local factors is the pH of wounds, studied in close relation to the local perfusion, oxygen tension, and lactate concentration. Granulation tissue with the wrong pH can hinder fibroblast and keratinocyte division and proliferation, as well as skin graft takes. Methods for influencing the pH have been tested, such as occlusion and acidification by the topical application of acidic media. In most trials, this has not changed the wound’s pH to an acidic one, but it has reduced the strong alkalinity of deeper or chronic wounds. Energy provision is essential for all repair processes. New insights into the metabolism of cells have changed the definition of lactate from a waste product to an indispensable energy provider in normoxic and hypoxic conditions. Neovascularization depends on oxygen provision and lactate, signaling hypoxic conditions even under normoxic conditions. An appropriate pH is necessary for successful skin grafting; hypoxia can change the pH of wounds. This review describes the close interconnections between the local lactate levels, metabolism, healing mechanisms, and pH. Furthermore, it analyzes and evaluates the different possible ways to support metabolism, such as lactate enhancement and pH adjustment. The aim of wound treatment must be the optimization of all these components. Therefore, the role of lactate and its influence on wound healing in acute and chronic wounds will be assessed.