Early Stages Of Wound Healing Research Articles

Absence of Langerhans cells resulted in over-influx of neutrophils and increased bacterial burden in skin wounds

Langerhans cells (LCs) are resident dendritic cells in the epidermis and their roles in presenting antigens derived from microorganisms present in the skin has been well appreciated. However, it is generally thought that incoming neutrophils are mainly responsible for eradicating invading pathogens in the early stage of wounds and a role of LCs in innate immunity is elusive. In the current study, we showed that wounds absent of LCs had a delayed closure. Mechanistically, LCs were the primary cells in warding off bacteria invasion at the early stage of wound healing. Without LCs, commensal bacteria quickly invaded and propagated in the wounded area. keratinocytes surrounding the wounds responded to the excessive bacteria by elevated production of CXCL5, resulting in an over-influx of neutrophils. The over-presence of activated neutrophils, possibly together with the aggravated invasion of bacteria, was detrimental to epidermal progenitor cell propagation and re-epithelialization. These observations underscore an indispensable role of LCs as effective guardians that preclude both bacteria invasion and damages inflicted by secondary inflammation.

Dandelion-shaped strontium-gallium microparticles for the hierarchical stimulation and comprehensive regulation of wound healing

Abstract The management of full-thickness skin injuries continues to pose significant challenges. Currently, there is a dearth of comprehensive dressings capable of integrating all stages of wound healing to spatiotemporally regulate biological processes following full-thickness skin injuries. In this study, we report the synthesis of a dandelion-shaped mesoporous strontium-gallium microparticle (GE@SrTPP) achieved through dopamine-mediated strontium ion biomineralization and self-assembly, followed by functionalization with gallium metal polyphenol networks (MPNs). As CroCfunctional wound dressing, GE@SrTPP can release bioactive ions in a spatiotemporal manner akin to dandelion seeds. During the early stages of wound healing, GE@SrTPP demonstrates rapid and effective hemostatic performance while also exhibiting antibacterial properties. In the inflammatory phase, GE@SrTPP promotes M2 polarization of macrophages, suppresses the expression of pro-inflammatory factors, and decreases oxidative stress in wounds. Subsequently, during the stages of proliferation and tissue remodeling, GE@SrTPP facilitates angiogenesis through the activation of the HIF-1α/VEGF pathway. Analogous to the dispersion and rooting of dandelion seeds, the root-like new blood vessels supply essential nutrients for wound healing. Ultimately, in a rat chronic wound model, GE@SrTPP achieved successful full-thickness wounds repair. In summary, these dandelion-shaped GE@SrTPP microparticles demonstrate comprehensive regulatory effects in managing full-thickness wounds, making them highly promising materials for clinical applications.

SFRP2 modulates functional phenotype transition and energy metabolism of macrophages during diabetic wound healing.

Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus, which causes great health damage and economic burden to patients. The pathogenesis of DFU is not fully understood. We screened wound healing-related genes using bioinformatics analysis, and full-thickness skin injury mice model and cellular assays were used to explore the role of target genes in diabetic wound healing. SFRP2 was identified as a wound healing-related gene, and the expression of SFRP2 is associated with immune cell infiltration in DFU. In vivo study showed that suppression of SFRP2 delayed the wound healing process of diabetic mice, impeded angiogenesis and matrix remodeling, but did not affect wound healing process of control mice. In addition, suppression of SFRP2 increased macrophage infiltration and impeded the transition of macrophages functional phenotypes during diabetic wound healing, and affected the transcriptome signatures-related to inflammatory response and energy metabolism at the early stage of wound healing. Extracellular flux analysis (EFA) showed that suppression of SFRP2 decreased mitochondrial energy metabolism and increased glycolysis in injury-related macrophages, but impeded both glycolysis and mitochondrial energy metabolism in inflammatory macrophages. In addition, suppression of SFRP2 inhibited wnt signaling-related genes in macrophages. Treatment of AAV-SFRP2 augmented wound healing in diabetic mice and demonstrated the therapeutic potential of SFRP2. In conclusions, SFRP2 may function as a wound healing-related gene in DFU by modulating functional phenotype transition of macrophages and the balance between mitochondrial energy metabolism and glycolysis.

The Influence of N-Acetylcysteine-Enriched Hydrogels on Wound Healing in a Murine Model of Type II Diabetes Mellitus.

Diabetes mellitus (DM) severely impairs skin wound healing capacity, yet few treatment options exist to enhance this process. N-acetylcysteine (NAC) is an antioxidant that improves cellular proliferation and enhances wound healing in healthy animals, yet its use in the context of type II DM has not been studied. The aim of our research was to investigate the effect of topically applied NAC-enriched hydrogels on wound healing in a leptin-deficient murine wound model. Four excisional wounds were created on the backs of 20 db/db mice and were subsequently treated with hydrogels containing NAC at concentrations of 5%, 10% and 20% or placebo (control). Healing was monitored for 28 days; photographs of the wounds were taken on every third day. Wound tissues were harvested on days 3, 7, 14 and 28 to undergo histological examinations. Wounds treated with 5% NAC showed improved wound closure speed accompanied by an increased dermal proliferation area on microscopic assessment compared with other groups. Higher concentrations of NAC failed to show a beneficial effect on wound healing. 5% NAC improved early stages of wound healing in a murine model of type II DM by increasing wound closure speed, likely mediated by improved dermal proliferation.

Integrating Bioactive Graded Hydrogel with Radially Aligned Nanofibers to Dynamically Manipulate Wound Healing Process.

Skin wound healing is a complex process that requires appropriate treatment and management. Using a single scaffold to dynamically manipulate angiogenesis, cell migration and proliferation, and tissue reconstruction during skin wound healing is a great challenge. We developed a hybrid scaffold platform that integrates the spatiotemporal delivery of bioactive cues with topographical cues to dynamically manipulate the wound-healing process. The scaffold comprised gelatin methacryloyl hydrogels and electrospun poly(ε-caprolactone)/gelatin nanofibers. The hydrogels had graded cross-linking densities and were loaded with two different functional bioactive peptides. The nanofibers comprised a radially aligned nanofiber array layer and a layer of random fibers. During the early stages of wound healing, the KLTWQELYQLKYKGI peptide, which mimics vascular endothelial growth factor, was released from the inner layer of the hydrogel to accelerate angiogenesis. During the later stages of wound healing, the IKVAVS peptide, which promotes cell migration, synergized with the radially aligned nanofiber membrane to promote cell migration, while the nanofiber membrane also supported further cell proliferation. In an in vivo rat skin wound-healing model, the hybrid scaffold significantly accelerated wound healing and collagen deposition, and the ratio of type I to type III collagen at the wound site resembled that of normal skin. The prepared scaffold dynamically regulated the skin tissue regeneration process in stages to achieve rapid wound repair with clinical application potential, providing a strategy for skin wound repair.

A Rheological Study on the Effect of Tethering Pro- and Anti-Inflammatory Cytokines into Hydrogels on Human Mesenchymal Stem Cell Migration, Degradation, and Morphology.

Polymer-peptide hydrogels are being designed as implantable materials that deliver human mesenchymal stem cells (hMSCs) to treat wounds. Most wounds can progress through the healing process without intervention. During the normal healing process, cytokines are released from the wound to create a concentration gradient, which causes directed cell migration from the native niche to the wound site. Our work takes inspiration from this process and uniformly tethers cytokines into the scaffold to measure changes in cell-mediated degradation and motility. This is the first step in designing cytokine concentration gradients into the material to direct cell migration. We measure changes in rheological properties, encapsulated cell-mediated pericellular degradation and migration in a hydrogel scaffold with covalently tethered cytokines, either tumor necrosis factor-α (TNF-α) or transforming growth factor-β (TGF-β). TNF-α is expressed in early stages of wound healing causing an inflammatory response. TGF-β is released in later stages of wound healing causing an anti-inflammatory response in the surrounding tissue. Both cytokines cause directed cell migration. We measure no statistically significant difference in modulus or the critical relaxation exponent when tethering either cytokine in the polymeric network without encapsulated hMSCs. This indicates that the scaffold structure and rheology is unchanged by the addition of tethered cytokines. Increases in hMSC motility, morphology and cell-mediated degradation are measured using a combination of multiple particle tracking microrheology (MPT) and live-cell imaging in hydrogels with tethered cytokines. We measure that tethering TNF-α into the hydrogel increases cellular remodeling on earlier days postencapsulation and tethering TGF-β into the scaffold increases cellular remodeling on later days. We measure tethering either TGF-β or TNF-α enhances cell stretching and, subsequently, migration. This work provides rheological characterization that can be used to design new materials that present chemical cues in the pericellular region to direct cell migration.

A new mechanism in negative pressure wound therapy: interleukin-17 alters chromatin accessibility profiling.

Negative pressure wound therapy (NPWT) is extensively used in clinical settings to enhance the healing of wounds. Despite its widespread use, the molecular mechanisms driving the efficacy of NPWT have not been fully elucidated. In this study, skin wound-healing models were established, with administration of NPWT. Vimentin, collagen I, and MMP9 of skin tissues were detected by immunofluorescence (IF). Gene expression analysis of skin wound tissues was performed by RNA-sequencing (RNA-seq). Protein expression was assayed by a Western blotting or IF assay, and mRNA levels were quantified by quantitative PCR. Chromatin accessibility profiles of fibroblasts following NPWT or IL-17 exposure were analyzed by ATAC-seq. In rat wound-healing models, NPWT promoted wound repair by promoting reepithelialization, extracellular matrix (ECM) synthesis, and proliferation, which mainly occurred in the early stage of wound healing. These differentially expressed genes (DEGs) in NPWT wounds versus control wounds were enriched in the IL-17 signaling pathway. IL-17 was identified as an upregulated factor following NPWT in skin wounds. Moreover, the IL-17 inhibitor secukinumab (SEC) could abolish the promoting effect of NPWT on wound healing. Importantly, chromatin accessibility profiles were altered following NPWT and IL-17 stimulation in skin fibroblasts. Our findings suggest that NPWT upregulates IL-17 to promote wound healing by altering chromatin accessibility, which is a novel mechanism for NPWT's efficacy in wound healing.NEW & NOTEWORTHY To our knowledge, this is the first report of the efficacy of negative pressure wound therapy (NPWT) in promoting wound healing via IL-17. Moreover, NPWT and IL-17 can alter chromatin accessibility. Our study identifies a novel mechanism for NPWT's efficacy in wound healing.

The Role of TNF-Alpha in the Wound Healing Process: Molecular and Clinical Perspectives - A Systematic Literature Review

Wounds are conditions of damage and partial loss of body tissue caused by physical trauma, sharp objects, blunt objects, temperature fluctuations, chemical exposure. Wound healing is a complex interaction between cells, cytokines, mediators, and blood vessels as a natural physiological response to tissue damage. TNF-α has a crucial role in the wound healing process, facilitating body immunity, immune cell mobilization, fibroblast cell proliferation, keratinocytes, and growth factor expression. Although TNF-alpha has benefits in the early stages of wound healing, excessively high levels or a sustained inflammatory response can lead to problems, such as excessive scar tissue formation or blockages, which can impede the wound healing process. This study utilized the PRISMA-ScR (Scoping Review) protocol. A review was conducted of articles discussing the Role of TNF-Alpha in the Wound Healing Process: Molecular and Clinical Perspectives within the last 10 years. Literature search in this study using PubMed, ScienceDirect, Elsivier and Google Scolar databases Search using English, abstract and full text. After searching with the keywords: The Role of TNF-Alpha, 19,022 articles were found. The search continued using the keyword The Role of TNF-Alpha in the Wound Healing found 346 articles. The last search using the keyword The Role of TNF-Alpha in the Wound Healing: Molecular and Clinical found 26 articles. TNF-α plays an important role in the early stages of cutaneous wound healing, significantly delayed after day 3, but not by day 7. TNF-α has a crucial role in the early stages of skin wound healing, and its administration is recognized to have a positive impact on the healing response, which may pave the way for innovative strategies to address chronic skin wound healing problems.

Electrospun Nanofibers Loaded with Marigold Extract Based on PVP/HPβCD and PCL/PVP Scaffolds for Wound Healing Applications.

Marigold flower is a traditionally used plant material topically applied on the skin due to its anti-inflammatory properties and antibacterial activity. This potential of action justifies the implementation of marigold extract in nanofiber scaffolds based on poly-vinylpyrrolidone/hydroxypropyl-β-cyclodextrin (PVP/HPβCD) and polycaprolactone/polyvinylpyrrolidone (PCL/PVP) obtained by electrospinning for wound treatment. Using SEM, the morphology of electrospun scaffolds showed a fiber diameter in the range of 298-527 nm, with a uniform and bead-free appearance. ATR-FTIR spectroscopy confirmed the presence of marigold extracts in nanofibrous scaffolds. The composition of the nanofibers can control the release; in the case of PVP/HPβCD, immediate release of 80% of chlorogenic acid (an analytical and functional marker for marigold extract) was achieved within 30 min, while in the case of PCL/PVP, the controlled release was achieved within 24 h (70% of chlorogenic acid). All systems showed weak antibacterial activity against skin and wound-infecting bacteria Staphylococcus aureus (MIC 100 mg/mL), and Pseudomonas aeruginosa (MIC 200 mg/mL) and yeasts Candida albicans (MIC 100 mg/mL). Analysis of the effect of different scaffold compositions of the obtained electrofibers showed that those based on PCL/PVP had better wound healing potential. The scratch was closed after 36 h, compared to the 48 h required for PVP/HPβCD. Overall, the study shows that scaffolds of PCL/PVP nanofibers loaded with classic marigold extract have the best potential as wound dressing materials because of their ability to selectively modulate inflammation (via inhibition of hyaluronidase enzyme) and supportive antimicrobial properties, thereby aiding in the early stages of wound healing and repair.

Bioactive nanomaterials kickstart early repair processes and potentiate temporally modulated healing of healthy and diabetic wounds

Slow-healing and chronic wounds represent a major global economic and medical burden, and there is significant unmet need for novel therapies which act to both accelerate wound closure and enhance biomechanical recovery of the skin. Here, we report a new approach in which bioactives that augment early stages of wound healing can kickstart and engender effective wound closure in healthy and diabetic, obese animals, and set the stage for subsequent tissue repair processes. We demonstrate that a nanomaterial dressing made of silk fibroin and gold nanorods (GNR) stimulates a pro-neutrophilic, innate immune, and controlled inflammatory wound transcriptomic response. Further, Silk-GNR, lasered into the wound bed, in combination with exogeneous histamine, accelerates early-stage processes in tissue repair leading to effective wound closure. Silk-GNR and histamine enhanced biomechanical recovery of skin, increased transient neoangiogenesis, myofibroblast activation, epithelial-to-mesenchymal transition (EMT) of keratinocytes and a pro-resolving neutrophilic immune response, which are hitherto unknown activities for these bioactives. Predictive and temporally coordinated delivery of growth factor nanoparticles that modulate later stages of tissue repair further accelerated wound closure in healthy and diabetic, obese animals. Our approach of kickstarting healing by delivering the “right bioactive at the right time” stimulates a multifactorial, pro-reparative response by augmenting endogenous healing and immunoregulatory mechanisms and highlights new targets to promote tissue repair.

Do Intraoperative Platelet-Rich Plasma Injections Influence the Final Appearance of Vertical Scars after Breast Reduction? Spectrophotometric Analysis

Background: Platelet-rich plasma (PRP) has been shown to support wound healing and tissue regeneration due to its high concentration of growth factors and cytokines. This study aims to investigate the effect of intraoperative PRP injections on the final appearance of vertical scars after breast reduction, as well as to identify potential predictors of a scar’s aesthetic assessment using spectrophotometric parameters. Methods: In this prospective, randomized trial, 82 scars from 41 women who underwent bilateral breast reduction with an inverted T pattern were analyzed. PRP or a placebo substance (0.9% sodium chloride solution) was injected intraoperatively into the edges of vertical wounds. Spectrophotometric measurements of scar pigmentation were performed 3 and 6 months after surgery; additionally, two independent observers evaluated the aesthetic appearance of scars based on photographs. Results: The results showed that the use of intraoperative PRP injections did not significantly influence the final appearance of vertical scars after breast reduction. Conclusions: We indicated spectrophotometric variables (b) in the early stages of wound healing (after 3 months) that can be predictors of the final scar’s aesthetic outcome. This can be helpful in detecting scars that may need additional interventions to optimize the healing process.

Aloe vera peel-derived nanovesicles display anti-inflammatory properties and prevent myofibroblast differentiation.

Aloe vera (AV) is a medicinal plant, most known for its beneficial effects on a variety of skin conditions. Its known active compounds include carbohydrates and flavonoids such as quercetin and kaempferol, among others. In the past decade, plant nanovesicles (NVs) have gained considerable interest as interkingdom communicators, presenting an opportunity for clinical standardization of natural products. In this study, we aimed to assess the potential of AVpNVs for the treatment of burn wounds. AVpNVs were isolated and characterized regarding vesicle yield (nanoparticle tracking analysis) and structure (transmission electron microscopy and atomic force microscopy), as well as their protein content with proteomics. We assessed key characteristics for treating burn wounds in vitro, such as the anti-inflammatory potential in LPS-stimulated macrophages and keratinocytes, and the effect of AVpNVs on myofibroblast differentiation and contraction. AVpNVs presented a homogenous NV population, vesicular shape, and NV-associated protein markers. AVpNVs significantly decreased the secretion of pro-inflammatory cytokines TNFα, IL-1β, and IL-6. Furthermore, AVpNVs inhibited myofibroblast differentiation and significantly decreased their contractile potential in collagen matrices. Observed effects were linked to proteins identified in the isolates through proteomics analysis. AVpNVs displayed characteristics as an inflammatory modulator, while simultaneously diminishing myofibroblast differentiation and contraction. Novel strategies for burn wound treatment seek to decrease scarring on a cellular and molecular level in the early stages of wound healing, which makes AVpNVs a promising candidate for future plant-vesicle-based treatments.

Early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and epithelial-mesenchymal transition during wound healing.

Due to vasculature injury and increased oxygen consumption, the early wound microenvironment is typically in a hypoxic state. We observed enhanced cell migration ability under early short-term hypoxia. CCL2 belongs to the CC chemokine family and was found to be increased in early hypoxic wounds and enriched in the extracellular signal-regulated kinase (ERK)1/2 pathway in our previous study. However, the underlying mechanism through which the CCL2-ERK1/2 pathway regulates wound healing under early short-term hypoxia remains unclear. Activation of epithelial-mesenchymal transition (EMT) is a key process in cancer cell metastasis, during which epithelial cells acquire the characteristics of mesenchymal cells and enhance cell motility and migration ability. However, the relationship between epithelial cell migration and EMT under early short-term hypoxia has yet to be explored. HaCaT cells were cultured to verify the effect of early short-term hypoxia on migration through cell scratch assays. Lentiviruses with silenced or overexpressed CCL2 were used to explore the relationship between CCL2 and migration under short-term hypoxia. An acute full-thickness cutaneous wound rat model was established with the application of an ERK inhibitor to reveal the hidden role of the ERK1/2 pathway in the early stage of wound healing. The EMT process was verified in all the above experiments through western blotting. In our study, we found that short-term hypoxia promoted cell migration. Mechanistically, hypoxia promoted cell migration through mediating CCL2. Overexpression of CCL2 via lentivirus promoted cell migration, while silencing CCL2 via lentivirus inhibited cell migration and the production of related downstream proteins. In addition, we found that CCL2 was enriched in the ERK1/2 pathway, and the application of an ERK inhibitor in vivo and in vitro verified the upstream and downstream relationships between the CCL2 pathway and ERK1/2. Western blot results both in vivo and in vitro demonstrated that early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and EMT during wound healing. Our work demonstrated that hypoxia in the early stage serves as a stimulus for triggering wound healing through activating the CCL2-ERK1/2 pathway and EMT, which promote epidermal cell migration and accelerate wound closure. These findings provide additional detailed insights into the mechanism of wound healing and new targets for clinical treatment.

Efficacy of one-hour negative pressure wound therapy and magnetic field energy in wound healing.

Wound healing is an important aspect of health but needs further research to identify the effects and interactions of different treatment approaches on healing. The aims of this study were to investigate the effectiveness of one-hour negative pressure wound therapy (NPWT) and compare histological differences between one-hour NPWT and magnetic field energy (MFE) in rats on early-stage wound healing, wound size and angiogenesis. Standardised wounds were created on Wistar rats that were allocated and divided into NPWT, MFE and control groups. Both treatments were applied for 1 hour/day for 10 days. Wound size, histological changes and wound area blood flow were assessed. The wound size of all groups was similar on days 0, 2 and 10. The MFE group's wound size was smaller than the NPWT group on days 4, 6 and 8 (p<0.05). Development of the granulation tissue in both the one-hour NPWT and MFE groups was greater than in the control group. Additionally, the inflammatory phase was shorter, and wounds entered the proliferative stage faster in the MFE group than both of the other groups. Treatment with MFE may be more effective in terms of early stage wound closure and angiogenesis. On the other hand, the NPWT group's wound area blood flow was significantly greater than the other two groups. MFE is superior to one-hour NPWT in terms of wound area and angiogenesis. Furthermore, it is worthwhile to note that one-hour NPWT increases bloodflow in the wound area, which stimulates healing.

A differential-targeting core-shell microneedle patch with coordinated and prolonged release of mangiferin and MSC-derived exosomes for scarless skin regeneration.

Microneedles for skin regeneration are conventionally restricted by uncontrollable multi-drug release, limited types of drugs, and poor wound adhesion. Here, a novel core-shell microneedle patch is developed for scarless skin repair, where the shell is composed of hydrophilic gelatin methacryloyl (GelMA) loaded with mangiferin, an anti-inflammatory small molecule, and the core is composed of hydrophobic poly (lactide-co-propylene glycol-co-lactide) dimethacrylates (PGLADMA) loaded with bioactive macromolecule and human mesenchymal stromal cell (hMSC)-derived exosomes. This material choice provides several benefits: the GelMA shell provides a swelling interface for tissue interlocking and rapid release of mangiferin at an early wound healing stage for anti-inflammation, whereas the PGLADMA core offers long-term encapsulation and release of exosomes (30% release in 3 weeks), promoting sustained angiogenesis and anti-inflammation. Our results demonstrate that the core-shell microneedle possesses anti-inflammatory properties and can induce angiogenesis both in vitro in terms of macrophage polarization and tube formation of human umbilical vein endothelial cells (HUVECs), and in vivo in terms of anti-inflammation, re-epithelization, and vessel formation. Importantly, we also observe reduced scar formation in vivo. Altogether, the degradation dynamics of our hydrophilic/hydrophobic materials enable the design of a core-shell microneedle for differential and prolonged release, promoting scarless skin regeneration, with potential for other therapies of long-term exosome release.

Wound Healing Improvement by Polymer Surgical Suture Coated with Tannic Acid

A surgical suture is a vital medical device to uphold wounded tissue during surgery. However, the application to improve tissue healing must still be developed. This study offered to solve this problem by incorporating tannic acid (TA) into polydioxanone (PDS) sutures. The PDS suture was immersed in TA complexing with iron (III) solutions in pH 8.0 solution. The engineered suture was successful, as revealed by the OH peak of TA in FTIR spectra. Furthermore, it was confirmed by TA particle appearance under Scanning Electron Microscopy. Contact angle measurement showed better wettability in biological mimicking solutions, such as water, serum, and saline solution. Thereby, it improved in vitro wound healing activity. Moreover, our bioinformatics data showed that TA enhanced the wound healing process by addressing multiple targets in the early phase of inflammation. For instance, it induced platelets to reduce bleeding at the early wound healing stage, activated T cells at the inflammation stage, accelerated epidermis cell proliferation, and activated fibroblast as a key player in wound healing. Due to multiple wound healing targets, our suture system was expected to be emphasized in clinical applications. HIGHLIGHTS The engineered surgical suture was fabricated by modifying the surface of surgical suture with tannic acid (TA) through iron (III) complex formation in basic condition The modified PDS suture had a high wettability degree of water, saline, and serum, representing the biological fluid, which was expected to have better biocompatibility Based on bioinformatics analysis, TA revealed multiple targets to stop bleeding by activating platelet through FYN, CD4, and CD8 T cells, induced epithelial cells proliferation through Epidermal Growth Factor Receptor (EGFR), and activated many transcription and migration factors of fibroblast GRAPHICAL ABSTRACT

Double-Layer Hydrogel with Glucose-Activated Two-Stage ROS Regulating Properties for Programmed Diabetic Wound Healing.

Slow healing of wounds induces great pain in diabetic patients. However, developing new approaches to promote diabetic wound healing is still one of the toughest challenges in the medical field. Here, we constructed a new double-layer hydrogel to effectively regulate reactive oxygen species (ROS) on the wound and promote diabetic wound healing. The inner layer contains glucose oxidase (Gox), ferrocene-modified quaternary ammonium chitosan (Fc-QCs), and poly(β-cyclodextrin) (Pβ-CD), which is used to generate hydroxyl radicals (•OH) for antibacterial in the early stage of wound healing and collapses gradually. The outer layer is composed of gelatin and dopamine. In the later stage of wound healing, the outer layer contacts the skin, which is beneficial for ROS clearance on the wound. Antibacterial, ROS scavenging, and wound healing experiments have shown that the double-layer hydrogel possesses two-stage ROS regulating properties for programmed diabetic wound healing. In conclusion, it will be one of the most potential dressings for treating diabetic wounds in the future.

Development and evaluation of tilapia skin-derived gelatin, collagen, and acellular dermal matrix for potential use as hemostatic sponges

Hemostasis plays a critical role in the early stage of wound healing, especially in acute wounds which can significantly improve the survival of patients. Based on the excellent biocompatibility of natural biomaterials, in this study, we prepared a series of novel hemostatic sponges by using tilapia skin, a marine biological resource, and extracting tilapia skin-derived gelatin, collagen, and acellular dermal matrix through five different methods. Using in vitro sheep blood and in vivo rat liver hemorrhage models, we found that tilapia skin sponges had excellent coagulation and hemostatic abilities. Among them, the collagen sponge exhibited optimal hemostasis performance because it could accelerate clotting by binding to the specific sites of blood cells and platelets. Furthermore, the sponges' porous structure enhanced the capability to absorb blood, thus effectively promoting hemostasis. In summary, we reported an efficient and convenient method to prepare marine biological resources into sponges, which provided a novel class of alternatives for hemostasis in acute wounds with broad application prospects.

Insufficient SIRT1 in macrophages promotes oxidative stress and inflammation during scarring.

Macrophage is a critical regulator in wound healing and scar formation, and SIRT1 is related to macrophage activation and polarization, while the specific mechanism is still unclear. To explore the specific effects of SIRT1 in scarring, we established a skin incision mouse model and LPS-induced inflammation cell model. The expression of SIRT1 in tissue and macrophage was detected, and the level of SIRT1 was changed to observe the downstream effects. LPS-induced macrophages with or without SIRT1 deficiency were used for TMT-based quantitative proteomic analysis. SIRT1 was suppressed in scar while increased in macrophages of scar tissue. And macrophages were proven to be necessary for wound healing. In the early stage of wound healing, knockout of SIRT1 in macrophage could greatly strengthen inflammation and finally promote scarring. NADH-related activities and oxidoreductase activities were differentially expressed in TMT-based quantitative proteomic analysis. We confirmed that ROS production and NOX2 level were elevated after LPS stimulation while the Nrf2 pathway and the downstream proteins, such as Nqo-1 and HO-1, were suppressed. In contrast, the suppression of SIRT1 strengthened this trend. The NF-κB pathway was remarkably activated compared with the control group. Insufficient increase of SIRT1 in macrophage leads to over activated oxidative stress and activates NF-κB pathways, which then promotes inflammation in wound healing and scarring. Further increasing SIRT1 in macrophages could be a promising method to alleviate scarring. KEY MESSAGES: SIRT1 was suppressed in scar while increased in macrophages of scar tissue. Inhibition of SIRT1 in macrophage leads to further activated oxidative stress. SIRT1 is negatively related to oxidative stress in macrophage. The elevation of SIRT1 in macrophage is insufficient during scarring.

EHO-85, Novel Amorphous Antioxidant Hydrogel, Containing Olea europaea Leaf Extract-Rheological Properties, and Superiority over a Standard Hydrogel in Accelerating Early Wound Healing: A Randomized Controlled Trial.

Many advanced wound healing dressings exist, but there is little high-quality evidence to support them. To determine the performance of a novel amorphous hydrogel (EHO-85) in relation to its application, we compared its rheological properties with those of other standard hydrogels (SH), and we assessed the induction of acceleration of the early stages of wound healing as a secondary objective of a prospective, multicenter, randomized, observer-blinded, controlled trial. The patients were recruited if they had pressure, venous, or diabetic foot ulcers and were treated with EHO-85 (n = 103) or VariHesive® (SH) (n = 92), and their response was assessed by intention-to-treat as wound area reduction (WAR (%)) and healing rate (HR mm2/day) in the second and fourth weeks of treatment. Results: EHO-85 had the highest shear thinning and G'/G″ ratio, the lowest viscous modulus, G″, and relatively low cohesive energy; EHO-85 had a significantly superior effect over SH in WAR and HR, accelerating wound healing in the second and fourth weeks of application (p: 0.002). This superiority is likely based on its optimal moisturizing capacity and excellent pH-lowering and antioxidant properties. In addition, the distinct shear thinning of EHO-85 facilitates spreading by gentle hand pressure, making it easier to apply to wounds. These rheological properties contribute to its improved performance.