Early Stages Of Wound Healing Research Articles

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

Negative pressure wound therapy (NPWT) is extensively employed 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 re-epithelialization, 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 up-regulated 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.

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.

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.

Aligned lovastatin-loaded electrospun nanofibers regulate collagen organization and reduce scar formation.

Excessive scar formation caused by cutaneous injury leads to pruritus, pain, contracture, dyskinesia, and unpleasant appearance. Functional wound dressings are designed to accelerate wound healing and reduce scar formation. In this study, we fabricated aligned or random polycaprolactone/silk fibroin electrospun nanofiber membranes with or without lovastatin loading, and then evaluated their scar-inhibitory effects on wounds under a specific tension direction. The nanofiber membranes exhibited good controlled-release performance, mechanical properties, hydrophilicity, and biocompatibility. Furthermore, nanofibers' perpendicular placement to the tension direction of the wound most effectively reduced scar formation (the scar area decreased by 66.9%) and promotedskin regeneration in vivo. The mechanism was associated with aligned nanofibers regulated collagen organization in the early stage of wound healing. Moreover, lovastatin-loaded nanofibers inhibited myofibroblast differentiation and migration. Both tension direction-perpendicular topographical cues and lovastatin synergistically inhibited mechanical transduction and fibrosis progression, further reducing scar formation. In summary, our study may provide an effective scar prevention strategy in which individualized dressings can be designed according to the local mechanical force direction of patients' wounds, and the addition of lovastatin can further inhibit scar formation. STATEMENT OF SIGNIFICANCE: In vivo, cells and collagen are always arranged parallel to the tension direction. However, the aligned topographic cues themselves promote myofibroblast differentiation and exacerbate scar formation. Electrospun nanofibers' perpendicular placement to the tension direction of the wound most effectively reduces scar formation and promotes skin regeneration in vivo. The mechanism is associated with tension direction-perpendicular nanofibers reregulate collagen organization in the early stage of wound healing. In addition, tension direction-perpendicular topographical cue and lovastatin could inhibit mechanical transduction and fibrosis progression synergistically, further reducing scar formation. This study proves that combining topographical cues of wound dressing and drugs would be a promising therapy for clinical scar management.

Hypothesis: Platelet-rich plasma accelerate diabetic wound healing via dynamic modulation of multiple signaling pathways

Diabetic wounds are a prevalent complication in patients with diabetes. Incremental platelet-rich plasma (PRP) administration has recently been used as an adjunct therapy for the treatment of diabetic ulcers. However, the exact signaling pathways involved in PRP-induced healing remain unclear. We speculated that PRP could mediate diabetic wound healing by dynamic modulation of signaling pathways including TGF-β/Smad, Wnt/β-catenin, Notch, NF-κB, MAPK, and PI3K/Akt, at different levels. PRP may have different effects (activation or inhibition) on different or even the same signal pathways depending on the stage of the healing process and concentration of growth factors within the PRP preparation. In the early stages of wound healing, some signaling pathways are initiated to reduce wound inflammation and oxidative stress, and promote angiogenesis and collagen regeneration. In the late stages of wound healing and scar formation, PRP may inhibit some signal pathways to prevent excessive fibroblast proliferation and deposition of extracellular matrix proteins such as collagen, thereby controlling excessive tissue proliferation at the wound site and minimizing scars. The various signaling pathways exhibit complex and context-dependent interactions; crosstalk between these pathways can lead to synergistic or antagonistic effects and regulate various cellular responses. This knowledge could be used to develop targeted therapies to optimize healing and reduce the risk of subsequent complications.

Histopathological Study on Collagen in Full-Thickness Wound Healing in Fraser's Dolphins (Lagenodelphis hosei).

Fraser's dolphins (Lagenodelphis hosei) possess great healing abilities. Their skin composition can be restored after wounding, including collagen spacing, orientation, and bundle thickness. However, it remains unclear how collagens are involved in the wound-healing process and eventually regain normality in Fraser's dolphins. Learned from the other two scarless healing animals, changes in type III/I collagen composition are believed to modulate the wound healing process and influence the scarring or scarless fate determination in human fetal skin and spiny mouse skin. In the current study, Herovici's, trichrome, and immunofluorescence staining were used on normal and wounded skin samples in Fraser's dolphins. The results suggested that type I collagens were the main type of collagens in the normal skin of Fraser's dolphins, while type III collagens were barely seen. During the wound healing process, type III collagens showed at early wound healing stages, and type I collagen increased in the mature healed wound. In an early healed wound, collagens were organized in a parallel manner, showing a transient hypertrophic-like scar, and eventually restored to normal collagen configuration and adipocyte distribution in the mature healed wound. The remarkable ability to remove excessive collagens merits further investigation to provide new insights into clinical wound management.

Local contamination is a major cause of early deep wound infections following open posterior lumbosacral fusions.

Postoperative surgical site infection in patients treated with lumbosacral fusion has usually been thought to be caused by perioperative contamination. With the proximity of these incisions to the perineum, this study sought to determine if contamination by gastrointestinal and/or urogenital flora should be considered as a major cause of this complication. We conducted a retrospective review of adults treated with open posterior lumbosacral fusions between 2014 and 2021 to identify common factors in deep postoperative infection and the nature of the infecting organisms. Cases of tumor, primary infection and minimally invasive surgery were excluded. 489 eligible patients were identified, 20 of which required debridement deep to the fascia (4.1%). Mean age, operative time, estimated blood loss and levels fused were similar between both groups. The infected group had a significantly higher BMI. The mean time from primary procedure to debridement was 40.8days. Four patients showed no growth, 3 showed Staphylococcus sp. infection (Perioperative Inside-Out) requiring debridement at 63.5days. Thirteen showed infection with intestinal or urogenital pathogens (Postoperative Outside-In) requiring debridement at 20.0days. Postoperative Outside-In infections led to debridement 80.3days earlier than Perioperative Inside-Out infections (p = 0.007). 65% of deep infections in patients undergoing open lumbosacral fusion were due to early contamination by pathogens associated with the gastrointestinal and/or urogenital tracts. These required earlier debridement than Staphylococcus sp. There should be renewed focus on keeping these pathogens away from the incision during the early stages of wound healing.

The total iridoid glycoside extract of Lamiophlomis rotata Kudo induces M2 macrophage polarization to accelerate wound healing by RAS/ p38 MAPK/NF-κB pathway.

Lamiophlomis rotata (Benth.) Kudo (L. rotata), a Tibetan medicinal plant, is used to treat "yellow-water diseases", such as skin disease, jaundice and rheumatism. Our previous study showed that the iridoid glycoside extract of L. rotata (IGLR) is the major constituent of skin wound healing. However, the role of IGLR in the biological process of trauma repair and the probable mechanism of the action remain largely unknown. To investigate the role of IGLR in the biological process of trauma repair and the probable mechanism of the action. The role of IGLR in wound healing was investigated by overall skin wound in mice with Hematoxylin and Eosin (H&E) and Masson trichrome staining. The anti-inflammatory, angiogenesis-promoting and fibril formation effects of IGLR were visualized in wound skin tissue by immunofluorescence staining, and the proinflammatory factors and growth factors were assayed by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Macrophages, dermal fibroblasts, and endothelial cells were cultured to measure the direct/indirect interaction effects of IGLR on the proliferation and migration of cells, and flow cytometry was employed to assess the role of IGLR on macrophage phenotype. Network pharmacology combined with Western blot experiments were conducted to explore possible mechanisms of the actions. IGLR increased the expression of CD206 (M2 markers) through the RAS/p38 MAPK/NF-κB signaling pathway during wound injury in vivo and in vitro. IGLR suppressed the inflammatory cytokines iNOS, IL-1β and TNF-α in the early stage of wound healing. During the proliferation step of wound repair, IGLR promoted angiogenesis and fibril formation by increasing the expression of VEGF, CD31, TGF-β and α-SMA in wound tissue, and similar results were verified by RT-PCR and ELISA. In a paracrine mechanism, the extract promoted the proliferation of dermal fibroblasts, and endothelial cells were founded by the conditioned medium (CM). IGLR induced M2 macrophage polarization in the early stage of wound healing; in turn, IGLR played a key role in the transition from inflammation to cell proliferation during the biological process of wound healing.

Amniotic Membrane Restores Chronic Wound Features to Normal in a Keratinocyte TGF-β-Chronified Cell Model

Unsuccessful wound closure in chronic wounds can be linked to altered keratinocyte activation and their inability to re-epithelize. Suggested mechanisms driving this impairment involve unbalanced cytokine signaling. However, the molecular events leading to these aberrant responses are poorly understood. Among cytokines affecting keratinocyte responses, Transforming Growth Factor-β (TFG-β) is thought to have a great impact. In this study, we have used a previously characterized skin epidermal in vitro model, HaCaT cells continuously exposed to TGF-β1, to study the wound recovery capabilities of chronified/senescent keratinocytes. In this setting, chronified keratinocytes show decreased migration and reduced activation in response to injury. Amniotic membrane (AM) has been used successfully to manage unresponsive complicated wounds. In our in vitro setting, AM treatment of chronified keratinocytes re-enabled migration in the early stages of wound healing, also promoting proliferation at later stages. Interestingly, when checking the gene expression of markers known to be altered in TGF-β chronified cells and involved in cell cycle regulation, early migratory responses, senescence, and chronic inflammation, we discovered that AM treatment seemed to reset back to keratinocyte status. The analysis of the evolution of both the levels of keratinocyte activation marker cytokeratin 17 and the spatial-temporal expression pattern of the proliferation marker Ki-67 in human in vivo biopsy samples suggests that responses to AM recorded in TGF-β chronified HaCaT cells would be homologous to those of resident keratinocytes in chronic wounds. All these results provide further evidence that sustained TGF-β might play a key role in wound chronification and postulate the validity of our TGF-β chronified HaCaT in vitro model for the study of chronic wound physiology.

Double Cross‐Linked Biomimetic Hyaluronic Acid‐Based Hydrogels with Thermo‐Stimulated Self‐Contraction and Tissue Adhesiveness for Accelerating Post‐Wound Closure and Wound Healing

AbstractWhen skin trauma occurs, rapid achievement of the post‐wound closure is required to prevent microbial invasion, inhibit scar formation and promote wound healing. To develop a wound dressing for accelerating post‐wound‐closure and wound healing, a thermo‐responsive and tissue‐adhesive hydrogel with interpenetrating polymer networks (IPN) is fabricated based on N‐dimethylbisacrylamide (NIPAM) and glutaraldehyde (GTA) cross‐linked hyaluronic acid (HA). Results not only confirm the thermo‐stimulated self‐contraction and tissue adhesiveness of the HA‐based IPN (PNI‐HA), which effectively aids wound closure via mechanical stretch, but also verify the hemocompatibility and cytocompatibility of PNI‐HA that tend to accelerate wound healing. In vivo, a mouse model of total skin defect demonstrates that PNI‐HA acting as hydrogel sealant significantly achieves the sutureless post‐wound‐closure at the early stage of wound healing, and then promotes wound healing by reducing inflammatory cells infiltration, promoting angiogenesis as well as reducing collagen deposition. These results indicate that the developed thermo‐responsive and tissue‐adhesive hydrogel dressing offers a candidate to serve as a tissue sealant for wound healing.