Treatment of diabetic foot wounds with acellular fish skin graft rich in omega-3: a prospective evaluation

Omega-3 Acellular Fish Skin Grafts for Chronic and Complicated Wounds: A Systematic Review of Efficacy and Safety

INTRODUCTION

A systematic review was conducted to investigate the efficacy of acellular fish skin grafts (AFSGs) for the treatment of complicated wounds. AFSGs can be used as a regenerative and antimicrobial tool for healing complicated wounds, but clinical evidence remains unclear.

OBJECTIVE

This systematic review aimed to summarize the efficacy of AFSGs on complicated wounds using evidence from existing published studies.

METHODS

Electronic databases like PubMed, ScienceDirect, Google Scholar, and Clinicaltrials.gov were searched for relevant literature reporting on the efficacy of AFSGs for wound healing. Based on the inclusion and exclusion criteria, nine studies were selected for data extraction. The quality of the articles was evaluated using the RoB 2 and ROBINS-I tools.

RESULTS

Existing evidence shows that AFSGs accelerate wound healing, reduce pain, prevent antibiotic administration, and cause no autoimmune reactions. The total re-epithelialization time for diabetic foot ulcers (DFUs) was observed as 15 ± 8 weeks, depending on the severity of the ulcers. Acute full thickness biopsy wounds healed within 3.75 ± 0.25 weeks. As reported in papers, AFSGs showed significantly better effects than standard-of-care therapy, collagen alginate dressings, dehydrated human AMNION/chorion membrane, and/ or porcine small-intestine submucosa. However, instances of rashes, erythema, pain, and hypergranulation were reported when AFSGs were applied to biopsy wounds.

CONCLUSION

Overall, the evidence obtained in this systematic review indicates that AFSGs represent a clinically and financially effective option for the treatment of wounds when compared with conventional alternatives.

Fish Skin Acellular Dermal Matrix Combined With Negative Pressure Wound Therapy for Diabetic Foot Ulcers

Background Managing diabetic foot ulcers (DFUs) is challenging due to poor blood supply, which leads to chronic wounds, increased susceptibility to infections, ischemia, and necrosis. The compromised quality of surrounding tissues, combined with complex underlying conditions and weakened immune systems, often hinders proper wound healing. Fish skin acellular dermal matrix (ADM) has emerged as an effective treatment option to promote healing in such wounds. Objective This study is the first to explore the use of fish skin ADM combined with negative pressure wound therapy (NPWT) for treating DFUs in the Asian population. The aim is to demonstrate the efficacy and effectiveness of this combined treatment approach. Methods Six patients with DFUs who visited the vascular surgery department between November 2022 and June 2023 were included in the study. Their wounds were treated with Kerecis® Omega3 Wound dressing for definitive closure, while NPWT was applied as an adjunct therapy to enhance graft uptake when suitable. Results The average initial wound size was 34.30 cm², with a complete healing rate of 100% achieved over an average of 19 weeks using Kerecis® Omega3 Wound dressing and adjunct NPWT. By the 12-week mark, the average reduction in wound size was 80.50%. Conclusions Fish skin ADM offers a biocompatible and sustainable solution for improving wound healing in difficult-to-treat DFUs. The addition of NPWT appears to enhance graft uptake, shorten the time to complete wound closure, and lower the risk of infections commonly associated with chronic diabetic foot wounds.

Extracellular matrix-based biomaterials in burn wound repair: A promising therapeutic strategy

Burns are common traumatic injuries affecting many people worldwide. Development of specialized burn units, advances in acute care modalities, and burn prevention programs have successfully reduced the mortality rate of severe burns. Autologous skin grafting has been considered as the gold standard for wound coverage after the removal of burned skin. For full-thickness burns of a larger scale, however, the autograft donor site may be quickly exhausted, so that alternative skin coverage is necessary. Although rapid progress has been made in the development of skin substitutes for burn wounds during the last decade, no skin substitute has fulfilled the criteria as a perfect replacement for the damaged skin. Extracellular matrix (ECM) derived components have emerged as a source for the engineering of biomaterials capable of inducing desirable cell-specific responses and one of the most promising biomaterials for burn wound healing. Among these, acellular dermal matrix, small intestinal submucosa, and amniotic membrane have been applied to treat burn wounds with acceptable outcomes. This review has explored the use of biomaterials derived from naturally occurring ECM and their derivatives for approaches aiming to promote burn wound healing, and summarized the ECM-based wound dressings products applicable in burn wound and postburn scar contracture to date.

Fish skin dressing for wound regeneration: A bioactive component review of omega-3 PUFAs, collagen and ECM

Wound healing is a complex biological process that involves several stages, including hemostasis, inflammation, proliferation, and remodeling. Traditional wound dressings, to a certain extent, can provide wound protection but are limited in promoting wound healing, reducing scar formation, and preventing bacterial infections. In recent years, with the advancement of research in biomedical materials, fish skin dressings have become a research hotspot in the field of tissue regeneration due to their remarkable biocompatibility and precious bioactive components. However, current research on fish skin dressings remains focused on clinical treatment. To further deepen and promote the development of fish skin dressings, we put emphasis on discussing main bioactive components in fish skin. This article has reviewed the advantages of fish skin dressings in wound regeneration, especially the promotive effects of its main bioactive components-Omega-3 polyunsaturated fatty acids, collagen derived from fish skin, and the extracellular matrix of fish skin-on the wound healing process. Besides, by critically summarizing the research issues of each bioactive component, this review assists researchers in better defining the next direction of research, thereby designing the optimal dressing for different types of wounds.

Decellularization of fish tissues for tissue engineering and regenerative medicine applications

Decellularization is the process of obtaining acellular tissues with low immunogenic cellular components from animals or plants while maximizing the retention of the native extracellular matrix structure, mechanical integrity and bioactivity. The decellularized tissue obtained through the tissue decellularization technique retains the structure and bioactive components of its native tissue; it not only exhibits comparatively strong mechanical properties, low immunogenicity and good biocompatibility but also stimulates in situ neovascularization at the implantation site and regulates the polarization process of recruited macrophages, thereby promoting the regeneration of damaged tissue. Consequently, many commercial products have been developed as promising therapeutic strategies for the treatment of different tissue defects and lesions, such as wounds, dura, bone and cartilage defects, nerve injuries, myocardial infarction, urethral strictures, corneal blindness and other orthopedic applications. Recently, there has been a growing interest in the decellularization of fish tissues because of the abundance of sources, less religious constraints and risks of zoonosis transmission between mammals. In this review, we provide a complete overview of the state-of-the-art decellularization of fish tissues, including the organs and methods used to prepare acellular tissues. We enumerated common decellularized fish tissues from various fish organs, such as skin, scale, bladder, cartilage, heart and brain, and elaborated their different processing methods and tissue engineering applications. Furthermore, we presented the perspectives of (i) the future development direction of fish tissue decellularization technology, (ii) expanding the sources of decellularized tissue and (iii) innovating decellularized tissue bio-inks for 3D bioprinting to unleash the great potential of decellularized tissue in tissue engineering and regenerative medicine applications.

Acellular Fish Skin Grafts for Treatment of Periocular Skin Defects

PURPOSE

To describe the outcomes of acellular fish skin grafts for repair of periocular anterior lamella skin defects after Mohs surgery for skin cancers.

METHODS

Following the institutional review board approval, the authors conducted a retrospective chart review of patients treated with acellular fish skin grafts between January 2022 and December 2023. Indication was to repair defects after Mohs excision of basal cell carcinoma and squamous cell carcinoma. Demographics, smoking and diabetes status, diagnosis, defect location, graft size, and complications were evaluated. Outcomes were analyzed using the scar cosmesis assessment and rating scale.

RESULTS

Six patients (3 females and 3 males) with a mean age of 60.8 (range 44-80) had Mohs surgery for basal cell carcinoma (4) and squamous cell carcinoma (2). Location of defects included eyebrow (3 cases), lateral nasal wall (1 case), lower eyelid (1 case), and medial lower eyelid/nasal wall (1 case). Defect size ranged from 8 × 10 mm to 30 × 40 mm. Two patients had more than 1 application of xenograft. One patient developed a mild cicatricial ectropion. No other postoperative complications were seen, and all had good wound healing and cosmetically acceptable results.

CONCLUSIONS

In this pilot study, acellular fish skin xenografts are shown to be promising skin graft substitutes in patients with Mohs defects and decrease the need for autologous skin harvesting or allogenic skin donation.

Treatment of hard-to-heal wounds in ischaemic lower extremities with a novel fish skin-derived matrix

OBJECTIVE

To evaluate the efficacy of treatment of hard-to-heal wounds of patients with ischaemia of the lower extremities, and compare an omega-3 wound matrix product (Kerecis, Iceland) with a standard dressing.

METHOD

A single-centre, prospective, randomised, controlled clinical trial of patients with hard-to-heal wounds following three weeks of standard care was undertaken. The ischaemic condition of the wound was confirmed as a decreased transcutaneous oxygen pressure (TcPO2) of <40mmHg. After randomising patients into either a case (omega-3 dressing) or a control group (standard dressing), the weekly decrease in wound area over 12 weeks and the number of patients that achieved complete wound closure were compared between the two groups. Patients with a TcPO2 of ≤32mmHg were taken for further analysis of their wound in a severe ischaemic context.

RESULTS

A total of 28 patients were assigned to the case group and 22 patients to the control group. Over the course of 12 weeks, the wound area decreased more rapidly in the case group than the control group. Complete wound healing occurred in 82% of patients in the case group and 45% in the control group. Even in patients with a severe ischaemic wound with a TcPO2 value of <32 mmHg, wound area decreased more rapidly in the case group than the control group. The proportions of re-epithelialised area in the case and control groups were 80.24% and 57.44%, respectively.

CONCLUSION

Considering the more rapid decrease in wound area and complete healing ratio in the case group, application of a fish skin-derived matrix for treating lower-extremity hard-to-heal wounds, especially with impaired vascularity, would appear to be a good treatment option.

Acellular fish skin grafts in the treatment of diabetic wounds: Advantages and clinical translation

Diabetic wounds cannot undergo normal wound healing due to changes in the concentration of hyperglycemia in the body and soon evolve into chronic wounds causing amputation or even death of patients. Diabetic wounds directly affect the quality of patients and social medical management; thus researchers started to focus on skin transplantation technology. The acellular fish skin grafts (AFSGs) are derived from wild fish, which avoids the influence of human immune function and the spread of the virus through low-cost decellularization. AFSGs contain a large amount of collagen and omega-3 polyunsaturated fatty acids and they have an amazing effect on wound regeneration. However, after our search in major databases, we found that there were few research trials in this field, and only one was clinically approved. Therefore, we summarized the advantages of AFSGs and listed the problems faced in clinical use. The purpose of this paper is to enable researchers to better carry out original experiments at various stages.

Efficacy of acellular fish skin graft in the management of chronic ulcer: a systematic review and meta-analysis

BACKGROUND

The wounds failing to heal through a timely and orderly standard of care (SOC) treatment are considered as chronic wounds, which add significant burden to healthcare systems around the world. SOC treatment has been commonly applied for management of chronic wounds, but SOC alone may not be adequate to heal all ulcers effectively. Fish skin graft (FSG) is a xenogenic skin substitute which could be used for accelerating skin healing. The current study was performed with the view of evaluating the effectiveness of FSG as an adjuvant treatment of SOC for chronic ulcer treatment.

METHODS

Two authors independently searched the following electronic databases: PubMed, Embase, and CENTRAL, using keywords including "diabetic foot ulcer," "fish skin graft," and "wound healing." Clinical studies that evaluated the clinical outcomes of FSG in treatment of chronic ulcers were included in this meta-analysis. Random- or fixed-effect modeled meta-analyses were performed according to the heterogeneity test result (i.e., I2), to analyze the clinical outcome of FSG.

RESULTS

A total of 8 studies were included in qualitative synthesis and meta-analysis, with 145 patients treated by SOC and 245 patients treated by SOC plus FSG. There was no significant difference between two groups for time to healing (MD = 1.99, 95% CI: -3.70~7.67, p = 0.493). The complete healing rate was significantly higher in FSG group compared with SOC alone (OR = 3.44, 95% CI: 2.03~5.82, p < 0.001***). Mean percentage area reduction (PAR) was reported in six studies, with a range of 71.6~97.3%. However, many of these studies did not report the value of standard deviation (SD), so we could not pool the data. No significantly different ulcer recurrence rate (RR = 0.60, 95% CI: 0.07~5.27, p = 0.645) and severe adverse events (SAEs) risk (RR = 1.67, 95% CI: 0.42~6.61, p = 0.467) were found between two groups.

CONCLUSIONS

The application of FSG treatment for patients with chronic ulcers that do not respond well to SOC management could significantly increase the complete healing rate compared with SOC alone, without increased recurrence rate and SAEs risk.

The Use of Photoactive Polymeric Nanoparticles and Nanofibers to Generate a Photodynamic-Mediated Antimicrobial Effect, with a Special Emphasis on Chronic Wounds

This review is concerned with chronic wounds, with an emphasis on biofilm and its complicated management process. The basics of antimicrobial photodynamic therapy (PDT) and its underlying mechanisms for microbial eradication are presented. Intrinsically active nanocarriers (polydopamine NPs, chitosan NPs, and polymeric micelles) that can further potentiate the antimicrobial photodynamic effect are discussed. This review also delves into the role of photoactive electrospun nanofibers, either in their eluting or non-eluting mode of action, in microbial eradication and accelerating the healing of wounds. Synergic strategies to augment the PDT-mediated effect of photoactive nanofibers are reviewed.

Fish By-Product Collagen Extraction Using Different Methods and Their Application

The processing of fishery resources results in the production of a growing quantity of byproducts, including heads, skins, viscera, intestines, frames, and fillet cutoffs. These byproducts are either wasted or utilized for the production of low-value items and fish oil. Typically, fish processing industries use only 25%, while the remaining 75% is considered as waste by-products. This review presents a comprehensive review on the extraction of collagen from fish byproducts, highlighting numerous techniques including acid-soluble collagen (ASC), enzyme-soluble collagen (ESC), ultrasound extraction, deep eutectic solvent (DES) extraction, and supercritical fluid extraction (SFE). A detailed explanation of various extraction parameters such as time, temperature, solid to liquid (S/L) ratio, and solvent/pepsin concentration is provided, which needs to be considered to optimize the collagen yield. Moreover, this review extends its focus to a detailed investigation of fish collagen applications in the biomedical sector, food sector, and in cosmetics. The comprehensive review explaining the extraction methods, extraction parameters, and the diverse applications of fish collagen provides a basis for the complete understanding of the potential of fish-derived collagen. The review concludes with a discussion of the current research and a perspective on the future development in this research field.

Exploring the Place of Fish Skin Grafts with Omega-3 in Pediatric Wound Management

Wound healing in the pediatric population is known to be a challenge and poorly studied. Split-thickness skin grafts, full-thickness skin grafts, and flaps overlap their applications with the growing field of cellular and tissue-based therapies. However, their role in pediatric reconstruction has yet to be defined. The Kerecis® Omega-3 wound patch, derived from decellularized codfish skin, has garnered attention due to its preserved microscopic architecture resembling the human extracellular matrix. This acellular dermal matrix acts as a scaffold, fostering dermal cell and capillary adhesion while harnessing omega-3 polyunsaturated fatty acids for granulation acceleration and antimicrobial effects. This study presents a comprehensive review and surgical protocol for utilizing Kerecis® fish skin in pediatric wound care. The research embraces a case series involving five patients with diverse wound locations. The Kerecis® Omega-3 wound patch underwent meticulous application and careful monitoring. The results highlight an average time of 48.6 days for complete epithelialization, yielding favorable outcomes with no hypertrophic scarring and mild retraction. Kerecis® fish skin grafting stands as a tool that not only accelerates healing but also addresses the multifaceted challenges associated with wound management in the pediatric population: the avoidance of donor site morbidity and improved postoperative pain control.

Processing and post-processing of fish skin as a novel material in tissue engineering

As a natural material, fish skin contains significant amounts of collagen I and III, and due to its biocompatible nature, it can be used to regenerate various tissues and organs. To use fish skin, it is necessary to perform the decellularization process to avoid the immunological response of the host body. In the process of decellularization, it is crucial to conserve the extracellular matrix (ECM) three-dimensional (3D) structure. However, it is known that decellularization methods may also damage ECM strands arrangement and structure. Moreover, after decellularization, the post-processing of fish skin improves its mechanical and biological properties and preserves its 3D design and strength. Also, sterilization, which is one of the post-processing steps, is mandatory in pre-clinical and clinical settings. In this review paper, the fish skin decellularization methods performed and the various post-processes used to increase the performance of the skin have been studied. Moreover, multiple applications of acellular fish skin (AFS) and its extracted collagen have been reviewed.

The Use of Intact Fish Skin Grafts in the Treatment of Necrotizing Fasciitis of the Leg: Early Clinical Experience and Literature Review on Indications for Intact Fish Skin Grafts

BACKGROUND

Necrotizing fasciitis (NF) is a serious infectious disease that can initially place the patient's life in danger and, after successful surgical and antibiotic treatment, leaves extensive wounds with sometimes even exposed bones and tendons. Autologous skin grafts are not always possible or require adequate wound bed preparation. Novel intact fish skin grafts (iFSGs; Kerecis® Omega3 Wound, Kerecis hf, Isafjördur, Iceland) have already shown their potential to promote granulation in many other wound situations. Faster wound healing rates and better functional and cosmetic outcomes were observed due to their additionally postulated anti-inflammatory and analgesic properties. Therefore, iFSGs may also be essential in treating NF. We present our initial experience with iFSGs in treating leg wounds after NF and review the literature for the current spectrum of clinical use of iFSGs.

CASE PRESENTATIONS

We present two male patients (aged 60 and 69 years) with chronic or acute postsurgical extensive leg ulcers six weeks and six days after necrotizing fasciitis, respectively. Both suffered from diabetes mellitus without vascular pathologies of the lower limbs. A single application of one pre-meshed (Kerecis® Graftguide) and one self-meshed 300 cm2 iFSG (Kerecis® Surgiclose) was performed in our operation room after extensive surgical debridement and single circles of negative wound pressure therapy. Application and handling were easy. An excellent wound granulation was observed, even in uncovered tibia bone and tendons, accompanied by pain relief in both patients. Neither complications nor allergic reactions occurred. The patients received autologous skin grafting with excellent functional and cosmetic outcomes.

CONCLUSIONS

iFSGs have the potential to play a significant role in the future treatment of NF due to the fast promotion of wound granulation and pain relief. Our experience may encourage surgeons to use iFSGs in NF patients, although high-quality, large-sized studies are still required to confirm these results. The observed effects of iFSGs on wounds associated with NF may be transferred to other wound etiologies as well.

Acellular fish skin for wound healing

Fish skin grafting as a new skin substitute is currently being used in clinical applications. Acceleration of the wound healing, lack of disease transmission, and low cost of the production process can introduce fish skin as a potential alternative to other grafts. An appropriate decellularization process allows the design of 3D acellular scaffolds for skin regeneration without damaging the morphology and extracellular matrix content. Therefore, the role of decellularization processes is very important to maintain the properties of fish skin. In this review article, recent studies on various decellularization processes as well as biological, physical, and mechanical properties of fish skin and its applications with therapeutic effects in wound healing were investigated.

Fish Skin Graft: Narrative Review and First Application for Abdominal Wall Dehiscence in Children

Acellular fish skin grafts (FSGs) are tissue-based products created by minimally processing the skin of the Atlantic cod (Gadus morhua). The FSG is rich in omega-3 and facilitates tissue regeneration by supporting revascularization and ingrowth in the proliferation and remodeling phases of wound healing. FSG is structurally more similar to human skin than antiviral-processed skin substitutes such as amniotic membrane, and there are no known prion, bacterial, or viral diseases that can be transmitted from North-Atlantic cod to humans. The FSG is processed using a proprietary method that preserves the structure and lipid composition of the skin. FSG is CE marked, and US Food and Drug Administration cleared for multiple clinical applications in partial and full-thickness wounds. FSG is currently the only acellular dermal matrix product that does not originate from mammalian tissues. For this narrative review, Medline and UpToDate were used to include a total of 21 articles published from 2015 to 2022 about fish skin graft use. We also reported a case of a 7-year-old boy who underwent treatment with FSG for abdominal wall dehiscence at our department of pediatric surgery, IRCCS Sant'Orsola-Malpighi, Alma Mater Studiorum, University of Bologna, University Hospital of Bologna. FSG provides a valuable and sustainable treatment that improves wound healing in both adult and pediatric populations. We described the first application of an FSG for wound dehiscence of the abdominal wall in a pediatric patient, reporting how FSG was completely reabsorbed and improved the skin's repair.

Current status and progress in research on dressing management for diabetic foot ulcer

Diabetic foot ulcer (DFU) is a major complication of diabetes and is associated with a high risk of lower limb amputation and mortality. During their lifetime, 19%-34% of patients with diabetes can develop DFU. It is estimated that 61% of DFU become infected and 15% of those with DFU require amputation. Furthermore, developing a DFU increases the risk of mortality by 50%-68% at 5 years, higher than some cancers. Current standard management of DFU includes surgical debridement, the use of topical dressings and wound decompression, vascular assessment, and glycemic control. Among these methods, local treatment with dressings builds a protective physical barrier, maintains a moist environment, and drains the exudate from DFU wounds. This review summarizes the development, pathophysiology, and healing mechanisms of DFU. The latest research progress and the main application of dressings in laboratory and clinical stage are also summarized. The dressings discussed in this review include traditional dressings (gauze, oil yarn, traditional Chinese medicine, and others), basic dressings (hydrogel, hydrocolloid, sponge, foam, film agents, and others), bacteriostatic dressings, composite dressings (collagen, nanomaterials, chitosan dressings, and others), bioactive dressings (scaffold dressings with stem cells, decellularized wound matrix, autologous platelet enrichment plasma, and others), and dressings that use modern technology (3D bioprinting, photothermal effects, bioelectric dressings, microneedle dressings, smart bandages, orthopedic prosthetics and regenerative medicine). The dressing management challenges and limitations are also summarized. The purpose of this review is to help readers understand the pathogenesis and healing mechanism of DFU, help physicians select dressings correctly, provide an updated overview of the potential of biomaterials and devices and their application in DFU management, and provide ideas for further exploration and development of dressings. Proper use of dressings can promote DFU healing, reduce the cost of treating DFU, and reduce patient pain.

Development of Matrix Metalloproteinases-Mediated Extracellular Matrix Remodeling in Regenerative Medicine: A Mini Review

Extracellular matrix (ECM) components confer biomechanical properties, maintain cell phenotype and mediate tissue homeostasis. ECM remodeling is complex and plays a key role in both physiological and pathological processes. Matrix metalloproteinases (MMPs) are a group of enzymes responsible for ECM degradation and have been accepted as a key regulator in ECM remodeling. In this mini-review, we summarize MMPs categories, functions and the targeted substrates. We then discuss current understanding of the role of MMPs-mediated events, including inflammation reaction, angiogenesis, cellular activities, etc., in ECM remodeling in the context of regenerative medicine.

Successful Treatment of Wounds from Nonuremic Calciphylaxis with Acellular Piscine Dermis

In this report, we present a 57-year-old man with chronic bilateral lower extremity wounds from nonuremic calciphylaxis, which were successfully reconstructed using a piscine-derived acellular dermal matrix. The acellular dermal matrix incorporated quickly, providing a wound bed that was amenable to skin grafting. We demonstrate that this is an effective off-the-shelf solution for these chronic wounds, resulting in pain reduction and complete closure of the wounds, allowing the patient to return to his previous baseline activities, and improving his quality of life.

Eicosapentaenoic acid-rich oil supplementation activates PPAR-γ and delays skin wound healing in type 1 diabetic mice

Delayed wound healing is a devastating complication of diabetes and supplementation with fish oil, a source of anti-inflammatory omega-3 (ω-3) fatty acids including eicosapentaenoic acid (EPA), seems an appealing treatment strategy. However, some studies have shown that ω-3 fatty acids may have a deleterious effect on skin repair and the effects of oral administration of EPA on wound healing in diabetes are unclear. We used streptozotocin-induced diabetes as a mouse model to investigate the effects of oral administration of an EPA-rich oil on wound closure and quality of new tissue formed. Gas chromatography analysis of serum and skin showed that EPA-rich oil increased the incorporation of ω-3 and decreased ω-6 fatty acids, resulting in reduction of the ω-6/ω-3 ratio. On the tenth day after wounding, EPA increased production of IL-10 by neutrophils in the wound, reduced collagen deposition, and ultimately delayed wound closure and impaired quality of the healed tissue. This effect was PPAR-γ-dependent. EPA and IL-10 reduced collagen production by fibroblasts in vitro. In vivo, topical PPAR-γ-blockade reversed the deleterious effects of EPA on wound closure and on collagen organization in diabetic mice. We also observed a reduction in IL-10 production by neutrophils in diabetic mice treated topically with the PPAR-γ blocker. These results show that oral supplementation with EPA-rich oil impairs skin wound healing in diabetes, acting on inflammatory and non-inflammatory cells.

Use of acellular intact fish skin grafts in treating acute paediatric wounds during the COVID-19 pandemic: a case series

Objective:

More specific strategies are needed to support children requiring skin grafting. Our goal was to identify procedures that reduce operating times, post-operative complications, pain and length of hospital stay. Patient safety, optimal wound bed support and quick micro-debridement with locoregional anaesthesia were prioritised. Ultimately, a novel acellular fish skin graft (FSG) derived from north Atlantic cod was selected for use.

Method:

We admitted consecutive paediatric patients with various lesions requiring skin grafting for definitive wound closure. All FSGs were applied and bolstered in the operating room following debridement.

Results:

In a cohort of 15 patients, the average age was 8 years and 9 months (4 years 1 month–13 years 5 months). Negative pressure wound therapy (NPWT) was given to 12 patients. Rapid wound healing was observed in all patients, with a wound area coverage of 100% and complete healing in 95% of wounds. Time until engraftment in patients receiving NPWT was reduced by about a half (to an average 12 days) from our standard experience of 21 days. Ten patients received locoregional anaesthesia and were discharged after day surgery. The operating time was <60 minutes, and no complications or allergic reactions were reported. Excellent pliability of the healed wound was achieved in all patients, without signs of itching and scratching in the postoperative period. This case series is the first and largest using FSG to treat paediatric patients with different wound aetiologies. We attribute the rapid transition to acute wound status and the good pliability of the new epidermal–dermal complex to the preserved molecular components of the FSG, including omega-3.

Conclusion:

FSG represents an innovative and sustainable solution for paediatric wound care that results in shorter surgery time and reduced hospital stays, with accelerated wound healing times.

Fish collagen for skin wound healing: a systematic review in experimental animal studies

Collagen extracted from fishes has been appearing as an alternative for commercial porcine and bovine collagen and it has been considered interesting especially for membrane manufacturing in tissue engineering. Despite the positive in vitro effects of fish collagen membranes, there is still no understanding of all the benefits that this natural biomaterial plays in the wound healing process, due to the lack of compilation of the results obtained in animal studies. In this sense, the purpose of this study was to perform a systematic review of the literature to examine the effects of fish collagen membranes for skin wound healing in experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "fish," collagen," "skin," and "in vivo". A total of 10 articles were retrieved from the databases PubMed and Scopus. After the elegibility analyses, this review covers the different origins of fish collagen reported in the different papers from the beginning of 2015 through the middle of 2021. The results were based mainly on histological analysis and macroscopic evaluation, and fish skin collagen was responsible for improving the wound healing rate and the process of reepithelization and collagen deposition. In conclusion, fish skin collagen has shown positive results in in vivo studies and may be a potential biomaterial in tissue engineering.

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.

Marine collagen scaffolds in tissue engineering

Collagen is the primary component of the extracellular matrix in humans. Traditionally commercial collagen is confined to bovine and porcine sources which have concerns of pathogenic transfer. Marine wastage accounts up to 85% by weight in the fishing industry. Extraction of collagen from these wastes for economic value and environmental sustainability is clear. Marine collagens have several advantages such as excellent biocompatibility, lower zoonotic risks, less immunological risk for patients allergic to mammalian products, and less religious restrictions. However, the properties of marine collagen-based constructs are highly dependent on the methods of fabrication. This article reviews advances in the design and fabrication of marine collagen-based constructs for medical applications. The potential applications of marine collagen in the regeneration of skin, bone and cartilage were also highlighted.

Acellular fish skin grafts for the management of wounds in dogs and cats: 17 cases (2019-2021)

OBJECTIVE

To report the clinical outcomes of the use of acellular fish skin grafts (FSGs) for the management of complex soft tissue wounds of various etiologies in dogs and cats.

ANIMALS

13 dogs and 4 cats with complex wounds treated with FSGs between February 2019 and March 2021.

PROCEDURES

Medical records were reviewed for information regarding cause, location, size of the wound, management techniques, complications, and clinical outcomes.

RESULTS

In dogs, the number of FSG applications ranged from 1 to 4 (median, 2 graft applications). The time between each application ranged from 4 to 21 days (median, 9.5 days). Time to application of the first FSG ranged from 9 to 210 days (median, 19 days). Wounds closed by second-intention healing following the first fish skin application between 26 and 145 days (median, 71 days; n = 12). In cats, 1 or 2 FSGs were used, and the wounds of 3 of 4 cats healed completely by secondary intention. The wounds of 1 dog and 1 cat did not heal. There were no adverse events attributed to the use of the FSGs.

CLINICAL RELEVANCE

For dogs and cats of the present study, complete healing of most wounds occurred with the use of FSGs, the application of which did not require special training, instruments, or bandage materials.

New Insights on the Effects of Dietary Omega-3 Fatty Acids on Impaired Skin Healing in Diabetes and Chronic Venous Leg Ulcers

Long-chain Omega-3 polyunsaturated fatty acids (Omega-3 PUFAs) are widely recognized as powerful negative regulators of acute inflammation. However, the precise role exerted by these dietary compounds during the healing process is still largely unknown, and there is increasing interest in understanding their specific effects on the implicated cells/molecular factors. Particular attention is being focused also on their potential clinical application in chronic pathologies characterized by delayed and impaired healing, such as diabetes and vascular diseases in lower limbs. On these bases, we firstly summarized the current knowledge on wound healing (WH) in skin, both in normal conditions and in the setting of these two pathologies, with particular attention to the cellular and molecular mechanisms involved. Then, we critically reviewed the outcomes of recent research papers investigating the activity exerted by Omega-3 PUFAs and their bioactive metabolites in the regulation of WH in patients with diabetes or venous insufficiency and showing chronic recalcitrant ulcers. We especially focused on recent studies investigating the mechanisms through which these compounds may act. Considerations on the optimal dietary doses are also reported, and, finally, possible future perspectives in this area are suggested.

Limited Treatment Options for Diabetic Wounds: Barriers to Clinical Translation Despite Therapeutic Success in Murine Models

Significance: Millions of people worldwide suffer from diabetes mellitus and its complications, including chronic diabetic wounds. To date, there are few widely successful clinical therapies specific to diabetic wounds beyond general wound care, despite the vast number of scientific discoveries in the pathogenesis of defective healing in diabetes. Recent Advances: In recent years, murine animal models of diabetes have enabled the investigation of many possible therapeutics for diabetic wound care. These include specific cell types, growth factors, cytokines, peptides, small molecules, plant extracts, microRNAs, extracellular vesicles, novel wound dressings, mechanical interventions, bioengineered materials, and more. Critical Issues: Despite many research discoveries, few have been translated from their success in murine models to clinical use in humans. This massive gap between bench discovery and bedside application begs the simple and critical question: what is still missing? The complexity and multiplicity of the diabetic wound makes it an immensely challenging therapeutic target, and this lopsided progress highlights the need for new methods to overcome the bench-to-bedside barrier. How can laboratory discoveries in animal models be effectively translated to novel clinical therapies for human patients? Future Directions: As research continues to decipher deficient healing in diabetes, new approaches and considerations are required to ensure that these discoveries can become translational, clinically usable therapies. Clinical progress requires the development of new, more accurate models of the human disease state, multifaceted investigations that address multiple critical components in wound repair, and more innovative research strategies that harness both the existing knowledge and the potential of new advances across disciplines.

Collagen in Wound Healing

Normal wound healing progresses through inflammatory, proliferative and remodeling phases in response to tissue injury. Collagen, a key component of the extracellular matrix, plays critical roles in the regulation of the phases of wound healing either in its native, fibrillar conformation or as soluble components in the wound milieu. Impairments in any of these phases stall the wound in a chronic, non-healing state that typically requires some form of intervention to guide the process back to completion. Key factors in the hostile environment of a chronic wound are persistent inflammation, increased destruction of ECM components caused by elevated metalloproteinases and other enzymes and improper activation of soluble mediators of the wound healing process. Collagen, being central in the regulation of several of these processes, has been utilized as an adjunct wound therapy to promote healing. In this work the significance of collagen in different biological processes relevant to wound healing are reviewed and a summary of the current literature on the use of collagen-based products in wound care is provided.

Acellular fish skin enhances wound healing by promoting angiogenesis and collagen deposition

Acellular matrix is a type of promising biomaterial for wound healing promotion. Although acellular bovine and porcine tissues have proven effective, religious restrictions and risks of disease transmission remain barriers to their clinical use. Acellular fish skin (AFS), given its similarity to human skin structure and without the aforementioned disadvantages, is thus seen as an attractive alternative. This study aims to fabricate AFS from the skin of black carp (Mylopharyngodon piceus), evaluate its physical and mechanical properties and assess its impact on wound healing. The results showed that AFS has a highly porous structure, along with high levels of hydrophilicity, water-absorption property and permeability. Furthermore, physical characterization showed the high tensile strength of AFS in dry and wet states, and high stitch tear resistance, indicating great potential in clinical applications. Cell Counting Kit-8 was used to test the viability of L929 cells when culturing in the extracts of AFS. Compared with the control group, there is no significant difference in optical density value when culturing in the extracts of AFS at days 1, 3 and 7 (*p> 0.05).In vivowound healing evaluation then highlighted its promotion of angiogenesis and collagen synthesis, its function in anti-inflammation and acceleration in wound healing. Therefore, this study suggests that AFS has potential as a promising alternative to mammal-derived or traditional wound dressing.

Accelerated Wound Closure of Deep Partial Thickness Burns with Acellular Fish Skin Graft

Thermal injuries are caused by exposure to a variety of sources, and split thickness skin grafts are the gold standard treatment for severe burns; however, they may be impossible when there is no donor skin available. Large total body surface area burns leave patients with limited donor site availability and create a need for treatments capable of achieving early and complete coverage that can also retain normal skin function. In this preclinical trial, two cellular and tissue based products (CTPs) are evaluated on twenty-four 5 × 5 deep partial thickness (DPT) burn wounds. Using appropriate pain control methods, DPT burn wounds were created on six anesthetized Yorkshire pigs. Wounds were excised one day post-burn and the bleeding wound beds were subsequently treated with omega-3-rich acellular fish skin graft (FSG) or fetal bovine dermis (FBD). FSG was reapplied after 7 days and wounds healed via secondary intentions. Digital images, non-invasive measurements, and punch biopsies were acquired during rechecks performed on days 7, 14, 21, 28, 45, and 60. Multiple qualitative measurements were also employed, including re-epithelialization, contraction rates, hydration, laser speckle, and trans-epidermal water loss (TEWL). Each treatment produced granulated tissue (GT) that would be receptive to skin grafts, if desired; however, the FSG induced GT 7 days earlier. FSG treatment resulted in faster re-epithelialization and reduced wound size at day 14 compared to FBD (50.2% vs. 23.5% and 93.1% vs. 106.7%, p < 0.005, respectively). No differences in TEWL measurements were observed. The FSG integrated into the wound bed quicker as evidenced by lower hydration values at day 21 (309.7 vs. 2500.4 µS, p < 0.05) and higher blood flow at day 14 (4.9 vs. 3.1 fold change increase over normal skin, p < 0.005). Here we show that FSG integrated faster without increased contraction, resulting in quicker wound closure without skin graft application which suggests FSG improved burn wound healing over FBD.

Collagen from Marine Sources and Skin Wound Healing in Animal Experimental Studies: a Systematic Review

Collagen (Col) from marine organisms has been emerging as an important alternative for commercial Col and it has been considered highly attractive by the industry. Despite the positive effects of Col from marine origin, there is still limited understanding of the effects of this natural biomaterial in the process of wound healing in animal studies. In this context, the purpose of this study was to perform a systematic review of the literature to examine the effects of Col from different marine species in the process of skin tissue healing using experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "marine collagen," "spongin," "spongin," "skin," and "wound." A total of 42 articles were retrieved from the databases PubMed and Scopus. After the eligibility analyses, this review covers the different marine sources of Col reported in 10 different papers from the beginning of 2011 through the middle of 2019. The results were based mainly on histological analysis and it demonstrated that Col-based treatment resulted in a higher deposition of granulation tissue, stimulation of re-epitalization and neoangiogenesis and increased amount of Col of the wound, culminating in a more mature morphological aspect. In conclusion, this review demonstrates that marine Col from different species presented positive effects on the process of wound skin healing in experimental models used, demonstrating the huge potential of this biomaterial for tissue engineering proposals.

Ultrasound assessment of deep tissue on the wound bed and periwound skin: A classification system using ultrasound images

AIMS

Given the utility of ultrasonography in assessing pressure injury, some ultrasonographic findings have already been used as indicators of deep tissue pressure injury. Despite reports showing that a cloud-like ultrasonographic pattern reflected the presence of deep tissue necrosis, identifying cloud-like patterns was difficult given the presence of similar findings, such as a cobblestone-like pattern. This case series reports patients with pressure injuries who presented with a cloud-like (five cases) and cobblestone-like (four cases) pattern during ultrasonography.

METHODS

This study was conducted at a Japanese university hospital. Participants included patients who underwent routine examination by an interdisciplinary pressure injury team. Pressure injury severity was assessed using the DESIGN-R® scoring system and the wound size were measured using ImageJ software based on the wound photograph.

RESULTS

Among the five cases showing a cloud-like pattern upon ultrasonography, all exhibited an increase in the total DESIGN-R® score, while three exhibited an increase in wound size. On the other hand, all four cases showing a cobblestone-like pattern displayed no increase in the total DESIGN-R® score and a decrease in wound size.

CONCLUSION

This study suggested that distinguishing between cloud-like and cobblestone-like ultrasonography patterns is necessary for determining the presence or absence of deep tissue pressure injury. In order to comprehensively assess pressure injuries with ultrasonography, future studies should be conducted in a large number of participants.