Enzymatic debridement of large burn wounds with papain-urea: Is it safe?

Enzymes for dermatological use

Skin is the ultimate barrier between body and environment and prevents water loss and penetration of pathogens and toxins. Internal and external stressors, such as ultraviolet radiation (UVR), can damage skin integrity and lead to disorders. Therefore, skin health and skin ageing are important concerns and increased research from cosmetic and pharmaceutical sectors aims to improve skin conditions and provide new anti-ageing treatments. Biomolecules, compared to low molecular weight drugs and cosmetic ingredients, can offer high levels of specificity. Topically applied enzymes have been investigated to treat the adverse effects of sunlight, pollution and other external agents. Enzymes, with a diverse range of targets, present potential for dermatological use such as antioxidant enzymes, proteases and repairing enzymes. In this review, we discuss enzymes for dermatological applications and the challenges associated in this growing field.

In Vitro Effect on the Proteolytic Activity of Papain with Proteins of the Skin as Substrate

OBJECTIVE

This work aims to evaluate the effects of enzyme concentration, pH, temperature, and time course degree of hydrolysis (DH) of papain regarding further development of pharmaceutical and cosmetic formulations.

METHODS

The hydrolysis of casein, collagen, keratin, and porcine skin at pH and temperature ranges of the human skin was evaluated. Also, low contact times of enzyme-substrate were studied. The incorporation of 3 mM of cysteine improved the caseinolytic (PU), collagenolytic (CU), and keratinolytic (KU) activities of papain.

RESULTS

In general, the increase from 0.1 to 1.0 or 2.0 mg mL^-1 of papain improved PU, CU, and KU. When 2.0 mg mL^-1 of papain was used, the highest DH of casein, collagen, and keratin were obtained at 240 min (14, 35, and 6%, respectively). The decrease in pH and temperature reduced all proteolytic activities, but papain maintained at least 50 and 40% of its activity at 26 °C and pH 4.5, respectively. Scanning electron micrographs of the surface of the skin showed that papain application had exfoliating activity.

CONCLUSION

This pre-formulation study demonstrated that papain concentration, time of application, and pH of the product should be evaluated when developing a product to promote the hydrolysis of the proteins of the skin.

Application Of The Enzymatic Debridement Of Burn Wounds In Patients During The Covid-19 Epidemic

The unfolding pandemic necessitated optimalization of treatment methods and assurance of the highest precautionary standards to prevent transmission of COVID-19 to burn patients. One of them included an expanded access treatment with the minimally invasive method - enzymatic burn wound debridement using Nexobrid concentrate. The study assessed the effectiveness and usefulness of the expanded treatment project using enzymatic burn wound debridement with Nexobrid concentrate in patients (n=11) during the pandemic (2020) when compared with the results of the same method in a corresponding period of 2019. The concentrate was applied to the wound on the third day following injury at the latest. All patients were treated with the same accepted standards, including initial debridement of the wound, application of Nexobrid concentrate, and removal of devitalized tissue and dressing. Clinical visual assessment of the wound sites confirmed successful debridement of dead tissue following the application of the concentrate. No allergic or adverse reaction, nor significant deterioration of CBC parameters were observed in any patient. Although surgical excision of necrosis is recognized as the method of choice, enzymatic wound debridement using Nexobrid concentrate may contribute to a reduction in epidemiological risk when treating burn patients for several reasons; the procedure can be performed at the patient's bedside, it limits the number of required surgeries, helps to improve medical equipment and supplies management, and saves human resources.

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.

Clinical Value of Debriding Enzymes as an Adjunct to Standard Early Surgical Excision in Human Burns: A Systematic Review

Burns are a significant public health burden worldwide. In addition to those who die, millions remain with life-threatening deformities and disabilities resulting in stigma and rejection. Surgical excision is currently the standard of care for removing necrotic tissues in burn wounds to prepare the wound bed for grafting or enhancing the healing process. However, there is a growing interest on enzymatic debridement as an adjunct therapy in burn wounds. The aim of this study was to investigate clinical trials using debriding agents for burn wound in humans in a systematic review. This was a systematic review of electronic databases including CINAHL, PubMed, Ovid Medline, Web of Science, Google Scholar, and Embase from January 1969 to February 2019. The study protocol was registered in PROSPERO registry. The following keywords were searched: "burn wounds", "enzymatic debridement", "papain", "papain-urea", "pine apple", "Bromelain", "collagenases", "Nexobrid", "Debrase", "Debridase", "Actinidia deliciosa", "Sutilains", "Debrace", "piruvat acid". Those studies fulfilling the inclusion and exclusion criteria with low score of bias based on Cochrane Bias Tool were reviewed. Sixteen investigations fulfilled our inclusion criteria to be reviewed. Six, seven, and three clinical trials on humans were found regarding collagenase, bromelain, and miscellaneous agents. Collagenase has been reported to be effective in burns below 25% of TBSA, especially in outpatients' clinics. However, Nexobrid has been shown to be effective in deep burns and decreases the percentage of graft without significant adverse effects. There was not enough evidence supporting the clinical values of Papain, Sutilains, Urea, etc. Surgical excision still remains the standard of care for burn wounds debridement. However, enzymatic debridement, especially Bromelain might help to reduce sessions for surgical debridement or area under graft as an adjunct treatment. Despite the fact, more studies with larger sample sizes and with less conflicts of interest are needed to clearly elucidate the exact role of Bromelain.

Evidence and Trends in Burn Wound Debridement: An Evidence Map

Treatment of the burn wound is crucial in care of severely burned patients. Surgical strategies differ in technique and timing of wound excision and are considered to have an impact on morbidity and mortality of burn patients. Most techniques and strategies have been established during the last century and are still standard of care. Nonetheless, several newer techniques have been presented and evaluated recently. To summarize the evidence and trends for eschar removal by burn wound debridement currently available, an evidence map as variant of the systematic review, was prepared. For this purpose, a systematic literature search was performed in the PubMed databases until December 2016. While overall evidence in this domain is low, recent publications focus on optimal timing of wound excision, enzymatic debridement, and hydrosurgery. Several studies report the benefit of an early wound excision in terms of shorter hospital stay, lower wound infection rate, and reduction of postburn metabolic changes. Enzymatic debridement has been shown to be an effective tool for early eschar removal and in addition reduces the need for autografting of the debrided burn wound with a relatively high level of evidence (LoE 2-). Wound debridement by means of hydrosurgery is more precise compared to conventional wound excision and preserves viable dermis, but a positive effect on wound healing or scar formation could not been shown (LoE 2). Furthermore, rarely reported techniques comprise larvae therapy, debridement by laser, and other technical adjuncts, but the level of evidence is limited (LoE 4-/5).

Enhanced Cellular Uptake and Sustained Transdermal Delivery of Collagen for Skin Regeneration

The present study reports a method for transporting high molecular weight collagen for skin regeneration. An independent engineered enzymatic vehicle that has the ability for efficient transdermal delivery of regenerative biomaterial was developed for tissue regeneration. Collagen has been well recognized as a skin regeneration molecule due to its interaction with the extracellular matrix to stimulate skin cell growth, proliferation, and differentiation. However, the transdermal delivery of collagen poses a significant challenge due to its high molecular weight as well as a lack of efficient approaches. Here, to improve the transdermal delivery efficiency, α-1,4-glycosidic hydrolase was engineered with genetically encoded 3,4-dihydroxy-L-phenylalanine, which enhanced its biological activity as revealed by microscale thermophoresis. The remodeled catalytic pocket resulted in enhanced substrate binding activity of the enzyme with a predominant glycosaminoglycan (chondroitin sulfate) present in the extracellular matrix of the skin. The engineered enzyme rapidly opened up the skin extracellular matrix fiber (15 min) to ferry collagen across the wall, without disturbing the cellular bundle architecture. Confocal microscopy indicated that macromolecules had diffused three times deeper into the engineered enzyme-treated skin than the native enzyme-treated skin. Gene expression, histopathology, and hematology analysis also supported the penetration of macromolecules. Cytotoxicity (mammalian cell culture) and in vivo (Caenorhabditis elegans and Rattus noryegicus) studies revealed that the congener enzyme could potentially be used as a penetration enhancer, which is of paramount importance for the multimillion cosmetic industries. Hence, it offers promise as a pharmaceutical enzyme for transdermal delivery bioenhancement and dermatological applications.

Enzymatic Debridement of Porcine Burn Wounds via a Novel Protease, SN514

Necrotic tissue generated by a thermal injury is typically removed via surgical debridement. However, this procedure is commonly associated with blood loss and the removal of viable healthy tissue. For some patients and contexts such as extended care on the battlefield, it would be preferable to remove devitalized tissue with a nonsurgical debridement agent. In this paper, a proprietary debridement gel (SN514) was evaluated for the ability to debride both deep-partial thickness (DPT) and full-thickness burn wounds using an established porcine thermal injury model. Burn wounds were treated daily for 4 days and visualized with both digital imaging and laser speckle imaging. Strip biopsies were taken at the end of the procedure. Histological analyses confirmed a greater debridement of the porcine burn wounds by SN514 than the vehicle-treated controls. Laser speckle imaging detected significant increases in the perfusion status after 4 days of SN514 treatment on DPT wounds. Importantly, histological analyses and clinical observations suggest that SN514 gel treatment did not damage uninjured tissue as no edema, erythema, or inflammation was observed on intact skin surrounding the treated wounds. A blinded evaluation of the digital images by a burn surgeon indicated that SN514 debrided more necrotic tissue than the control groups after 1, 2, and 3 days of treatment. Additionally, SN514 gel was evaluated using an in vitro burn model that used human discarded skin. Treatment of human burned tissue with SN514 gel resulted in greater than 80% weight reduction compared with untreated samples. Together, these data demonstrate that SN514 gel is capable of debriding necrotic tissue and suggest that SN514 gel could be a useful option for austere conditions, such as military multi-domain operations and prolonged field care scenarios.

Advanced drug delivery systems and artificial skin grafts for skin wound healing

Cutaneous injuries, especially chronic wounds, burns, and skin wound infection, require painstakingly long-term treatment with an immense financial burden to healthcare systems worldwide. However, clinical management of chronic wounds remains unsatisfactory in many cases. Various strategies including growth factor and gene delivery as well as cell therapy have been used to enhance the healing of non-healing wounds. Drug delivery systems across the nano, micro, and macroscales can extend half-life, improve bioavailability, optimize pharmacokinetics, and decrease dosing frequency of drugs and genes. Replacement of the damaged skin tissue with substitutes comprising cell-laden scaffold can also restore the barrier and regulatory functions of skin at the wound site. This review covers comprehensively the advanced treatment strategies to improve the quality of wound healing.

Collagenolytic Enzymes and their Applications in Biomedicine

Nowadays, enzymatic therapy is a very promising line of treatment for many different diseases. There is a group of disorders and conditions, caused by fibrotic and scar processes and associated with the excessive accumulation of collagen that needs to be catabolized to normalize the connective tissue content. The human body normally synthesizes special extracellular enzymes, matrix metalloproteases (MMPs) by itself. These enzymes can cleave components of extracellular matrix (ECM) and different types of collagen and thus maintain the balance of the connective tissue components. MMPs are multifunctional enzymes and are involved in a variety of organism processes. However, under pathological conditions, the function of MMPs is not sufficient, and these enzymes fail to deal with disease. Thus, medical intervention is required. Enzymatic therapy is a very effective way of treating such collagen-associated conditions. It involves the application of exogenous collagenolytic enzymes that catabolize excessive collagen at the affected site and lead to the successful elimination of disease. Such collagenolytic enzymes are synthesized by many organisms: bacteria, animals (especially marine organisms), plants and fungi. The most studied and commercially available are collagenases from Clostridium histolyticum and from the pancreas of the crab Paralithodes camtschatica, due to their ability to effectively hydrolyse human collagen without affecting other tissues, and their wide pH ranges of collagenolytic activity. In the present review, we summarize not only the data concerning existing collagenase-based medications and their applications in different collagen-related diseases and conditions, but we also propose collagenases from different sources for their potential application in enzymatic therapy.

Current therapies in treatment and prevention of fracture wound biofilms: why a multifaceted approach is essential for resolving persistent infections

Traumatic orthopedic injuries, particularly extremity wounds, are a significant cause of morbidity. Despite prophylactic antibiotic treatment and surgical intervention, persistent infectious complications can and do occur. Persistent bacterial infections are often caused by biofilms, communities of antibiotic tolerant bacteria encased within a matrix. The structural and metabolic differences in this mode of growth make treatment difficult. Herein, we describe both established and novel, experimental treatments targeted at various stages of wound healing that are specifically aimed at reducing and eliminating biofilm bacteria. Importantly, the highly tolerant nature of these bacterial communities suggests that most singular approaches could be circumvented and a multifaceted, combinatorial approach will be the most effective strategy for treating these complicated infections.

Trends and Prospects of Plant Proteases in Therapeutics

The main function of proteases in any living organism is the cleavage of proteins resulting in the degradation of damaged, misfolded and potentially harmful proteins and therefore providing the cell with amino acids essential for the synthesis of new proteins. Besides this main function, proteases may play an important role as signal molecules and participate in numerous protein cascades to maintain the vital processes of an organism. Plant proteases are no exception to this rule. Moreover, in contrast to humanencoded enzymes, many plant proteases possess exceptional features such as higher stability, unique substrate specificity and a wide pH range for enzymatic activity. These valuable features make plant-derived proteolytic enzymes suitable for many biomedical applications, and furthermore, the plants can serve as factories for protein production. Plant proteases are already applied in the treatment of several pathological conditions in the human organism. Some of the enzymes possess antitumour, antibacterial and antifungal activity. The collagenolytic activity of plant proteases determines important medical applications such as the healing of wounds and burn debridement. Plant proteases may affect blood coagulation processes and can be applied in the treatment of digestive disorders. The present review summarizes recent advances and possible applications for plant proteases in biomedicine, and proposes further development of plant-derived proteolytic enzymes in the biotechnology and pharmaceutical industries.

Skin permeability enhancement by Bacillus subtilis alkaline protease: Application to transdermal drug delivery

Enzymes may offer great potentials in topical pharmaceutical applications provided that treatment conditions are controlled for efficacy and safety. In this study, the effect of alkaline protease produced by recombinant Bacillus subtilis cells on the ex-vivo permeability of rabbit ear skin was investigated under different conditions of enzyme activity (5-60 units) and exposure time (15-60min). Data for transepidermal water loss (TEWL) and permeation of a hydrophilic dye, rhodamine B (Rb), indicated biphasic activity-dependent and exposure time-dependent skin permeability. Maximum effects were obtained at 20 proteolytic units and 30min exposure. Findings proved consistent with histopathological changes indicating progressive stratum corneum (SC) loss and disruption of the dermo-epidermal junction at 20 units and up to 30min exposure time followed by dermal hyalinization at longer exposure. This was associated with progressive loss of skin hair. Applying the identified pretreatment conditions to transdermal delivery of vardenafil in a gel base across dorsal rat skin indicated a significant increase in plasma levels at 30 and 60min with minimal histopathological changes 5days post enzyme treatment. Accordingly, the recombinant B. subtilis alkaline protease offers promise as a pharmaceutical enzyme for transdermal drug delivery bioenhancement and dermatological applications.

Efficiency of Enzymatic Debridement in the Healing Process of Chronic Wounds in Small Animal Practice

Skin wounds are a common presentation in small animal practice. These wounds may be acute or chronic with a complicated healing process. An important aspect of the healing of wounds is debridement which may be carried out by surgical, autolytic, mechanical or enzymatic methods. The debridement method is chosen according to the individual skin defect and influenced by factors such as wound size and location, the age of the wound, and the presence of infection or exudate. Enzymatic debridement is a method that is not commonly used in veterinary practice, and involves the use of enzyme preparations to remove necrotic tissue from a wound. The aim of this study was to investigate the effects of the enzymatic ointment collagenase as a method of debridement, and its effect on the macroscopic appearance of chronic skin wounds in cats and dogs. We observed that the application of Iruxol Mono directly to the wound changes the progress of the healing process, with no obvious adverse effects. The time of healing of chronic wounds was decreased and healthy granulation tissue was developed within a couple of days after application of the ointment. Enzymatic debridement appears to be a promising method of debridement for use in chronic wounds, and should be considered in cases where more conventional methods of debridement are ineffective or unsuitable.

Literature review on the management of diabetic foot ulcer

Diabetic foot ulcer (DFU) is the most costly and devastating complication of diabetes mellitus, which affect 15% of diabetic patients during their lifetime. Based on National Institute for Health and Clinical Excellence strategies, early effective management of DFU can reduce the severity of complications such as preventable amputations and possible mortality, and also can improve overall quality of life. The management of DFU should be optimized by using a multidisciplinary team, due to a holistic approach to wound management is required. Based on studies, blood sugar control, wound debridement, advanced dressings and offloading modalities should always be a part of DFU management. Furthermore, surgery to heal chronic ulcer and prevent recurrence should be considered as an essential component of management in some cases. Also, hyperbaric oxygen therapy, electrical stimulation, negative pressure wound therapy, bio-engineered skin and growth factors could be used as adjunct therapies for rapid healing of DFU. So, it’s suggested that with appropriate patient education encourages them to regular foot care in order to prevent DFU and its complications.