The marine Omega3 wound matrix for treatment of complicated wounds: A multicenter experience report

Fish skin grafts versus standard of care on wound healing of chronic diabetic foot ulcers: A systematic review and meta-analysis

INTRODUCTION

This study will explore the effectiveness of fish skin grafts (FSG) in ulcer healing in diabetic foot disease compared to standard of care (SOC).

METHODS

The systematic review and meta-analysis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard. The electronic databases of PubMed, EMBASE, and Web of Science (WoS) internet were searched for the outcome rate of complete ulcer healing. The risk of bias assessment was conducted using the tool recommended by the Cochrane Collaboration. Statistical analysis included the individual and combined result of the studies, heterogeneity test, the effect size, sensitivity analysis, and publication bias tests.

RESULTS

Five randomised controlled trials (RCTs) with a total of 411 patients were included in this study. This meta-analysis showed a higher rate of complete ulcer healing in groups receiving fish skin grafts (OR = 3.34, 95% CI 2.14-5.20, p < 0.01, I2 = 0%) compared to control groups.

CONCLUSION

Fish skin grafts have been shown to be more effective for achieving complete ulcer healing compared to current conventional treatments in diabetic foot disease.

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.

The Role of Fish Skin Xenografts in Healing Complex Wounds: A Brief Case Report

Non-healing wounds profoundly impact patient quality of life and present a significant financial burden. The Kerecis™ fish skin xenograft is a decellularized skin matrix that has been introduced to treat complicated wounds. The objective of this presentation is to highlight the use of fish skin xenograft in the treatment of a complex right flank wound with stool contamination, necrotizing soft tissue infection due to perforated colon cancer, and sepsis. This presentation follows the wound healing for 28 days following the operation and demonstrates the efficacy of fish skin xenografts in improved wound healing. A 61-year-old female with a past medical history of colon cancer and recent chemotherapy treatment presented with colon perforation causing right flank cellulitis and sepsis with necrotic abdominal wall tissue extending into the hip joint. She was taken for an emergent exploratory laparotomy, drainage of abdominal and retroperitoneal abscesses, open right hemicolectomy, diverting ileostomy, abdominal washout, intra-abdominal omental patch, placement of Strattice mesh, and debridement of necrotizing soft tissue infection of the right flank. After extensive debridement of her 15x10cmx5cm deep wound and placement of a Kerecis™ fish skin xenograft, the wound had completely healed with excellent granulation tissue, and the patient was scheduled for placement of a skin graft 28 days following the initial procedure. The results after xenograft application were outstanding, supporting the use of polyunsaturated fatty acid (PUFA) based xenografts in wound treatment due to their anti-inflammatory and angiogenic properties. This is definitely an option that needs to be considered in expediting the healing process for complex wounds.

In Situ Sodium Chloride Cross-Linked Fish Skin Collagen Scaffolds for Functional Hemostasis Materials

Current fish collagen hemostasis for wound healing products is commonly obtained by electrospinning or artificial cross-linking fish collagen fibers which lacks mechanical properties, and biofunctions. Here, a new bio-active fish skin scaffold (FSS) is shown using in situ cross-linked scaleless freshwater fish skin adding adipose-derived stem cells (ASCs)-produced exosomes for hemostasis and wound healing. The structure, pore size, and the thickness of FSS is studied by swelling test, Fourier-transform infrared (FT-IR) spectra, scanning electron microscope (SEM) images, and histological analysis. The biofunctions of the FSS are also tested in vitro and in vivo. FSS keeps two functional layers: The dermis layer collagen forms a sponge like structure after swelling and in situ cross-linking treatments. The pore size of the FSS is ≈152 ± 23.54 µm, which is suitable for cells growing, angiogenesis and ASCs exosomes accelerate wound healing. The fat-rich epidermis layer can keep the wound moisty and clean before completely healed. In vitro and in vivo experimental results indicate that FSS+Exosomes enhances rat skin cavity wound healing. In situ sodium chloride cross-linked FSS+Exosomes provides a new strategy as functional hemostatic dressing scaffold for wound healing.

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.

Management of Severe Burn Wounds Colonized With Multi-resistant Pseudomonas aeruginosa and Fusarium Using Marine Omega3 Wound Matrix in a Female Victim of War

War-related burns are common injuries, also among the civilian population. Additional trauma such as fractures or shrapnel wounds may add significant morbidity. Burn injuries in war zones are furthermore frequently undertreated and hence prone to complications. We report a case of a young female victim of war, whose severely infected burn wounds could be successfully healed using a combination of targeted antimicrobial therapy, wound conditioning using decellularized fish skin, and subsequent skin grafting.

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.

The Use of Acellular Tissue Matrices in Gender-Affirming Surgery: Review of the Literature and Institutional Experience

Wound healing complications are not uncommon after genital gender-affirming surgery and can pose significant challenges for the reconstructive surgeon. Acellular tissue matrices are products that contain extracellular matrix compounds without living cells and are used to expedite and improve wound healing. Some of these products have been described for a variety of different indications in gender-affirming surgery.  In this paper, the authors present a review of the current literature on the use of acellular tissue matrices in gender-affirming surgery as well as the authors' institutional experience in using these products.

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.

Flexible Conductive Decellularized Fish Skin Matrix as a Functional Scaffold for Myocardial Infarction Repair

Engineering cardiac patches are proven to be effective in myocardial infarction (MI) repair, but it is still a tricky problem in tissue engineering to construct a scaffold with good biocompatibility, suitable mechanical properties, and solid structure. Herein, decellularized fish skin matrix is utilized with good biocompatibility to prepare a flexible conductive cardiac patch through polymerization of polydopamine (PDA) and polypyrrole (PPy). Compared with single modification, the double modification strategy facilitated the efficiency of pyrrole polymerization, so that the patch conductivity is improved. According to the results of experiments in vivo and in vitro, the scaffold can promote the maturation and functionalization of cardiomyocytes (CMs). It can also reduce the inflammatory response, increase local microcirculation, and reconstruct the conductive microenvironment in infarcted myocardia, thus improving the cardiac function of MI rats. In addition, the excellent flexibility of the scaffold, which enables it to be implanted in vivo through "folding-delivering-re-stretehing" pathway, provides the possibility of microoperation under endoscope, which avoids the secondary damage to myocardium by traditional thoracotomy for implantation surgery.

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.

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.

Recent advances in decellularized biomaterials for wound healing

The skin is one of the most essential organs in the human body, interacting with the external environment and shielding the body from diseases and excessive water loss. Thus, the loss of the integrity of large portions of the skin due to injury and illness may lead to significant disabilities and even death. Decellularized biomaterials derived from the extracellular matrix of tissues and organs are natural biomaterials with large quantities of bioactive macromolecules and peptides, which possess excellent physical structures and sophisticated biomolecules, and thus, promote wound healing and skin regeneration. Here, we highlighted the applications of decellularized materials in wound repair. First, the wound-healing process was reviewed. Second, we elucidated the mechanisms of several extracellular matrix constitutes in facilitating wound healing. Third, the major categories of decellularized materials in the treatment of cutaneous wounds in numerous preclinical models and over decades of clinical practice were elaborated. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues for research on decellularized biomaterials-based wound treatment.

Intact Fish Skin Graft vs. Standard of Care in Patients with Neuroischaemic Diabetic Foot Ulcers (KereFish Study): An International, Multicentre, Double-Blind, Randomised, Controlled Trial Study Design and Rationale

BACKGROUND

Cell and/or tissue-based wound care products have slowly advanced in the treatment of non-healing ulcers, however, few studies have evaluated the effectiveness of these devices in the management of severe diabetic foot ulcers.

METHOD

This study (KereFish) is part of a multi-national, multi-centre, randomised, controlled clinical investigation (Odin) with patients suffering from deep diabetic wounds, allowing peripheral artery disease as evaluated by an ankle brachial index equal or higher than 0.6. The study has parallel treatment groups: Group 1 treatment with Kerecis^® Omega3 Wound™ versus Group 2 treatment with standard of care. The primary objective is to test the hypothesis that a larger number of severe diabetic ulcers and amputation wounds, including those with moderate arterial disease, will heal in 16 weeks when treated with Kerecis^® Omega3 Wound™ than with standard of care.

CONCLUSION

This study has received the ethics committee approval of each participating country. Inclusion of participants began in March 2020 and ended in July 2022. The first results will be presented in March 2023. The study is registered in ClinicalTrials.gov as Identifier: NCT04537520.

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.

Wound healing ability of acellular fish skin and bovine collagen grafts for split-thickness donor sites in burn patients: Characterization of acellular grafts and clinical application

Due to its high polyunsaturated fatty acid content, acellular fish skin has emerged as a dermal substitute for the promotion of wound healing as it decreases scar formation while providing pain relief. However, various systematic studies on acellular fish skin, such as its biophysical analysis, in vitro activities, and clinical application, have not been sufficiently investigated. In this study, we conducted a comparative study to evaluate the wound-healing ability of acellular fish skin graft (Kerecis®) with that of the widely used bovine collagen skin graft (ProHeal®). The skin grafts were evaluated not only in terms of their biophysical properties, but also their in vitro cellular activities, using fibroblasts, keratinocytes, and human endothelial cells. The clinical study evaluated wound healing in 52 patients with acute burns who underwent skin grafting on donor sites from January 2019 to December 2020. The study was conducted with two groups; while only Kerecis® was tested in one group, Kerecis® and ProHeal® were compared in the other. In both groups, the application time of the dressing material was one to two days after split-thickness skin grafting to the donor sites. The Kerecis®-treatment group experienced faster healing than the other treatment group. In particular, the average wound healing time using the Kerecis® treatment and the ProHeal® treatment was 10.7 ± 1.5 days and 13.1 ± 1.4 days, respectively. We believe that the faster healing of the Kerecis® treatment, compared to that of the ProHeal® treatment, maybe due to the synergistic effect of the unique biophysical structure and the bioactive components of acellular fish skin.

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.

Lipid mediator profiles of burn wound healing: Acellular cod fish skin grafts promote the formation of EPA and DHA derived lipid mediators following seven days of treatment

The use of acellular fish skin grafts (FSG) for the treatment of burn wounds is becoming more common due to its beneficial wound healing properties. In our previous study we demonstarted that FSG is a scaffold biomaterial that is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) conjugated to phosphatidylcholines. Here we investigated whether EPA and DHA derived lipid mediators are influenced during the healing of burn wounds treated with FSG. Deep partial and full thickness burn wounds (DPT and FT, respectively) were created on Yorkshire pigs (n = 4). DPT were treated with either FSG or fetal bovine dermis while FT were treated either with FSG or cadaver skin initially and followed by a split thickness skin graft. Punch biopsies were collected on days 7, 14, 21, 28 and 60 and analyzed in respect of changes to approximately 45 derivatives of EPA, DHA, arachidonic acid (AA), and linoleic acid (LA) employing UPLC-MS/MS methodology. Nine EPA and DHA lipid mediators, principally mono-hydroxylated derivatives such as 18-HEPE and 17-HDHA, were significantly higher on day 7 in the DPT when treated with FSG. A similar but non-significant trend was observed for the FT. The results suggest that the use of FSG in burn wound treatment can alter the formation of EPA and DHA mono hydroxylated lipid mediators in comparison to other grafts of mammalian origin. The differences observed during the first seven days after treatment indicates that FSG affects the early stages of wound healing.

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.

Impact of the chronic wound microenvironment and marine omega-3 fatty acids on skin cell regeneration processes

Marine long-chain omega-3 polyunsaturated fatty acids (ω3 FA) are involved in numerous cell responses and therefore vital for the mammal organism. Because of the attribution of immunomodulatory effects, a favourable impact on the inflammatory response in chronic wounds and cells involved in wound healing can be suspected. In the experimental setup, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were investigated regarding their impact on metabolic activity, cell proliferation and migration of human keratinocytes (HaCaT) and newborn foreskin fibroblasts (CRL-2522). For simulation of the microenvironment of a chronic wound, human chronic wound fluid (CWF) was used in the experimental setup addressing the in vitro influence of DHA, EPA and CWF on regenerative processes. The results showed a significant increase in the metabolic activity of keratinocytes and fibroblasts after 72 h treatment with DHA and EPA. In contrast, treatment with ω3 FA had no significant positive effect on skin cell proliferation. Both ω3 FA had no influence on in vitro wound closure. CWF demonstrated significantly adverse effects, which ω3 FA were unable to mitigate. It can be concluded that CWF exhibited the expected adverse effect on both skin cell types, especially inhibiting in vitro wound closure. ω3 FAs showed a slightly positive, yet rarely significant effect on human skin cells. Overall, the addition of DHA or EPA showed no relevant benefit for skin cells challenged with human CWF, merely in combination with DHA an initial significant increase in cell metabolism (fibroblasts) and cell proliferation (keratinocytes) could be observed.

Extraction of Fatty Acids and Phenolics from Mastocarpus stellatus Using Pressurized Green Solvents

Polyunsaturated fatty acids are well known for their protective properties in relation to different skin diseases. Although seaweeds possess a low lipid fraction, they could act as an alternative renewable source of polyunsaturated fatty acids whenever other valuable seaweed components are also valorized. In this study, a biorefinery process using Mastocarpus stellatus as a model seaweed was proposed. The process started with the supercritical carbon dioxide extraction of the lipid and phenolic fractions. The influence of pressure during extraction with pure supercritical CO₂ was studied while operating at a selected temperature and solvent flow rate. Kinetic data obtained during the ethanol-modified supercritical CO₂ extraction were fitted to the spline model. Sequential processing was proposed with (i) pure CO₂ to obtain a product with 30% PUFA content and ω-3:ω-6 ratio 1:1, (ii) ethanol-modified CO₂ to extract phenolics, and (iii) microwave-assisted subcritical water extraction operating under previously optimized conditions for the extraction of phenolics, carrageenan and protein fractions. The composition of the supercritical extracts showed potential for use in both dietary and topical applications in skin care products. The remaining solids are suitable for the extraction of other valuable fractions.

Evaluation of a novel tilapia-skin acellular dermis matrix rationally processed for enhanced wound healing

Acellular Dermal Matrix (ADM) is mainly made with human or porcine skins and has the risk of zoonotic virus transmission. The fish skin-derived ADM could overcome the shortcoming. Fish skin acellular matrix has been used as wound dressing, but there is few systematic studies on tilapia-skin acellular dermal matrix (TS-ADM). In the present study, a novel TS-ADM was made by an alkaline decellularization process and γ-irradiation. The physical properties, biocompatibility, pre-clinical safety and wound healing activity of TS-ADM were systematically evaluated for its value as a functionally bioactive wound dressing. Histopathological analysis (hematoxylin and eosin staining, 4,6-diamidino-2-phenylindole (DAPI) staining) and DNA quantification both proved that the nuclear components of tilapia skin were removed sufficiently in TS-ADM. Compared to the commercial porcine acellular dermal matrix (DC-ADM), TS-ADM has distinctive features in morphology, thermal stability, degradability and water vapor transmission. TS-ADM was more readily degradable than DC-ADM in vitro and in vivo. In both rat and mini-pig skin wound healing experiments, TS-ADM was shown to significantly promote granulation growth, collagen deposition, angiogenesis and re-epithelialization, which may be attributed to the high expression of transforming growth factor-beta 1 (TGF-β1), alpha-smooth muscle actin (α-SMA) and CD31. Herein, the novel TS-ADM, used as a low-cost bioactive dressing, could form a microenvironment conducive to wound healing.

Wound healing grafts: Omega-3 fatty acid lipid content differentiates the lipid profiles of acellular Atlantic cod skin from traditional dermal substitutes

Acellular fish skin (ACS) has emerged as a dermal substitute used to promote wound healing with decreased scar formation and pain relief that may be due to polyunsaturated fatty acid (PUFA) content. However, the PUFA content of ACS is still unknown. The aim of this study was to compare the total fatty acids and lipid profiles of ACS to two bovine-based grafts and standard of care human cadaver skin (HCS). Furthermore, there was also the goal to assess the capability of ACS lipid content to enhance wound healing. The fatty acid analysis was performed with GC-FID, and an LC-MS untargeted method was developed in order to the analyse the lipid profiles of the grafts was. The enhancement of wound healing by the ACS extract was investigated in vitro on HaCat cells. Our results showed that ACS had the highest content of PUFA (27.0 ± 1.43% of their total fatty acids), followed by HCS (20.6 ± 3.9%). The two grafts of bovine origin presented insignificant PUFA amounts. The majority of the PUFAs found in ACS were omega-3, and in HCS, they were omega-6. The untargeted lipidomics analysis demonstrated that ACS grafts were characterized by phosphatidylcholine containing either 20:5 or 22:6 omega-3 PUFA. The ACS lipid extract increased the HaCat cells migration and enhanced wound closure 4 hr earlier versus control. Our study demonstrated that ACS has a lipid profile that is distinct from other wound healing grafts, that PUFAs are maintained in ACS post-processing as phosphatidylcholine, and that ACS lipid content influences wound healing properties.

Polymeric Electrospun Fibrous Dressings for Topical Co-delivery of Acyclovir and Omega-3 Fatty Acids

Herpetic infections caused by Herpes simplex virus (HSV) are among the most common human infections, affecting more than two quarters of the world's population. The standard treatment for orofacial herpes is the administration of antiviral drugs, mainly acyclovir (ACV). However, current products are mostly based on semisolid formulations that have limited ability to promote drug skin penetration and tend to leak from the application site, thus showing reduced ability to sustain local drug residence. This work reports on the production of poly (ε-caprolactone) (PCL) fibrous matrices with ACV and omega-3 fatty acids (ω3) for application as dressings to the topical treatment of orofacial herpes. PCL fibrous matrices with the co-incorporated bioactive compounds were obtained by electrospinning and characterized regarding their morphology, chemical, physical, and mechanical properties. The potential use of the developed polymeric fibrous matrices for topical applications was evaluated by: (i) the release kinetics of the bioactive compounds; (ii) the occlusive factor of the fibrous mat; (iii) ACV skin permeation capacity; and (iv) the cytotoxicity in a keratinocyte cell line. PCL fibrous matrices loaded with the bioactive compounds presented a smooth morphology and a good balance between flexibility and hardness essential to be durable for handling, while having a desirable texture to be used comfortably. The fibrous mat also provided a sustained release of ACV during 96 h and improved the skin permeability of this drug (Kp = 0.00928 ± 0.000867 cm/h) presenting also high porosity (74%) and a water vapor transmission rate (WVTR) of 881 ± 91 g/m²day, essential to maintain moist and oxygen for faster healing of herpes lesions. Furthermore, cytotoxicity studies suggest that the fibrous mat are safe for topical application. Overall, the PCL based electrospun fibrous matrices with ACV and ω3 hereby described have the potential to be used as therapeutic bandage systems for the treatment of orofacial herpes.