Enhanced Wound Closure Research Articles

Norway Spruce Balm: Phytochemical Composition and Ability to Enhance Re-epithelialization In Vitro.

The balm of the Norway spruce (Picea abies) is a well-known traditional herbal medicine used to cure wounds. Even though clinical trials have confirmed its empirical use, the active constituents, their mode of action, and the exact composition of this natural product are still unknown. In this study, the balm was subjected to fractionated extraction and further purified employing flash chromatography, HPLC-PDA-ELSD, preparative and analytical TLC. Hydroxycinnamic acids ( 1: - 3: ), the lignan pinoresinol ( 4: ), four hydroxylated derivatives of dehydroabietic acid (DHAA) ( 5: - 8: ), and dehydroabietic acid ( 9: ) were isolated. Their structures were elucidated by LC-MS, 1D- and 2D-NMR. Four extracts, two commercially available resin acids-pimaric acid ( 10: ) and isopimaric acid ( 11: )-and the isolated compounds were tested for increased re-epithelialization of cell-free areas in a human adult low calcium high temperature keratinocytes monolayer. Lysophosphatidic acid (10 µM) served as positive control and ranged between 100% and 150% rise in cell-covered area related to the vehicle control. Two extracts containing carboxylic acids and non-acidic apolar constituents, respectively, boosted wound closure by 47% and 36% at 10 and 3 µg/mL, respectively. Pinoresinol, DHAA, three of its hydroxylated derivatives, and pimaric and isopimaric acid as well as defined combinations of the hydroxylated DHAA derivatives led to a significantly enhanced wound closure by up to 90% at concentrations between 1 and 10 µM. Overall, lignans and diterpene resin acids, main constituents of Norway spruce balm, are able to increase migration or proliferation of keratinocytes in vitro. The presented data link the phytochemistry of this natural wound healing agent with boosted re-epithelialization.

Heparan Sulfate Deficiency Enhances Wound Healing

Heparan sulfate has many biological activities, in particular positive effects on growth factor signaling and cell adhesion. Thus, mutations in heparan sulfate assembly typically manifest in loss‐of‐function, leading to developmental defects or altered physiology. Here, we demonstrate that genetic and pharmacological reduction of heparan sulfate enhances wound healing, a gain‐of‐function phenotype. In one model, 8‐week‐old mice were shaved and subjected to a full thickness 6‐mm diameter punch biopsy through the dorsal skin. Imaging of the wound over two weeks showed that wound closure occurred more rapidly in mice bearing a defect in Ext gene function, which encodes the copolymerase responsible for the assembly of the backbone of the chain. Enhanced wound closure also occurred after tamoxifen‐induced deficiency of heparan sulfate in skin (Rosa26‐CreER; Ext1flox/flox mice) or in keratinocytes (K14‐CreER; Ext1flox/fflox). Wildtype mice treated orally with xyloside also showed significant enhancement in dermal wound repair. We conclude that manipulation of the levels of heparan sulfate in vivo increases the capacity for wound repair, suggesting a novel approach for enhancing the regenerative property of tissues.

Conductive adhesive self-healing nanocomposite hydrogel wound dressing for photothermal therapy of infected full-thickness skin wounds

Bacteria-infected wounds and antibiotics abuse have become significant burdens to patients and medical systems. Thus, designing a non-antibiotic-dependent multifunctional wound dressing for treating bacteria-infected wounds is urgently desired. Herein, a series of conductive self-healing and adhesive nanocomposite hydrogels with a remarkable photothermal antibacterial property based on N-carboxyethyl chitosan (CEC) and benzaldehyde-terminated Pluronic F127/carbon nanotubes (PF127/CNT) were developed, and their great potential as agents for photothermal therapy (PTT) of infected wounds was demonstrated in vivo. The hydrogels exhibited a suitable gelation time, stable mechanical properties, hemostatic properties, high water absorbency, and good biodegradability. After loading the antibiotic moxifloxacin hydrochloride, the hydrogels showed a pH-responsive release profile and good antibacterial activity. The tissue adhesive property of the hydrogels allowed them to have a good hemostatic effect in a mouse liver trauma model, mouse liver incision model, and mouse tale amputation model. The addition of CNTs endowed the hydrogel with in vitro/in vivo photothermal antimicrobial activity and good conductivity. An in vivo experiment in a mouse full-thickness skin wound-infected model indicated that the hydrogels had an excellent treatment effect leading to significantly enhanced wound closure healing, collagen deposition, and angiogenesis. In summary, these conductive photothermal self-healing nanocomposite hydrogels as multifunctional wound dressing exhibit great potential for the treatment of infected wounds.

A human epidermal growth factor-curcumin bandage bioconjugate loaded with mesenchymal stem cell for in vivo diabetic wound healing.

Bone-marrow-derived mesenchymal stem cells (MSCs) are of growing interest for the treatment of diabetic wound healing. However, they are often associated with poor proliferation and viability at the wounded site. Here, it is reported the use of human epidermal growth factor -curcumin bandage bioconjugate (EGF-Cur B) loaded with MSCs (MSCs-EGF-Cur B) at the wounded site for diabetic wound healing. Conjugation efficiency of EGF was determined by FTIR and XPS, surface morphology was analyzed by SEM and AFM and hydrophilicity by contact angle. Chemical integrity of curcumin with the polymeric matrix was studied by FTIR and, antiinflamatory and biocompatibility of EGF-Cur B were determined by TNF α ELISA and MTT study respectively. The culture of MSCs over EGF-Cur B enhanced MSC viability and expression of transcription factors associated with the maintenance of pluripotency and self-renewal (OCT¾, SOX2, and Nanog) as compared to MSCs grown in standard conditions. Its therapeutic effect was examined on diabetic full-thickness excisional wound model in terms of size and histological examination. Synergetic combinational approach especially when treated with MSCs-EGF-Cur B significantly enhanced wound closure by increasing granulation tissue formation, collagen deposition, and angiogenesis as compared to other groups. In conclusion, biocompatible therapeutic MSCs-EGF-Cur B might have great application for diabetic wound healing in the near future.

Antibacterial Activity and Pharmacokinetic Profile of a Promising Antibacterial Agent: 22-(2-Amino-phenylsulfanyl)-22-Deoxypleuromutilin.

A new pleuromutilin derivative, 22-(2-amino-phenylsulfanyl)-22-deoxypleuromutilin (amphenmulin), has been synthesized and proved excellent in vitro and in vivo efficacy than that of tiamulin against methicillin-resistant Staphylococcus aureus (MRSA), suggesting this compound may lead to a promising antibacterial agent to treat MRSA infections. In this study, the effectiveness and safety of amphenmulin were further investigated. Amphenmulin showed excellent antibacterial activity against MRSA (minimal inhibitory concentration = 0.0156~8 µg/mL) and performed time-dependent growth inhibition and a concentration-dependent postantibiotic effect (PAE). Acute oral toxicity test in mice showed that amphenmulin was a practical non-toxic drug and possessed high security as a new drug with the 50% lethal dose (LD50) above 5000 mg/kg. The pharmacokinetic properties of amphenmulin were then measured. After intravenous administration, the elimination half-life (T1/2), total body clearance (Clβ), and area under curve to infinite time (AUC0→∞) were 1.92 ± 0.28 h, 0.82 ± 0.09 L/h/kg, and 12.23 ± 1.35 μg·h/mL, respectively. After intraperitoneal administration, the T1/2, Clβ/F and AUC0→∞ were 2.64 ± 0.72 h, 4.08 ± 1.14 L/h/kg, and 2.52 ± 0.81 μg·h/mL, respectively, while for the oral route were 2.91 ± 0.81 h, 6.31 ± 2.26 L/h/kg, 1.67 ± 0.66 μg·h/mL, respectively. Furthermore, we evaluated the antimicrobial activity of amphenmulin in an experimental model of MRSA wound infection. Amphenmulin enhanced wound closure and promoted the healing of wound, which inhibited MRSA bacterial counts in the wound and decreased serum levels of the pro-inflammatory cytokines TNF-α, IL-6, and MCP-1.

Safety and Efficacy of Human Adipose-Derived Stromal/Stem Cell Therapy in an Immunocompetent Murine Pressure Ulcer Model

Pressure injuries/ulcers are frequent complications in elderly, paraplegic, and quadriplegic patients, which account for considerable cost to the international health care economy and remain refractory to current treatment options. Autologous or allogeneic adult stromal/stem cells represent an alternative therapeutic approach. The current study extends prior findings by exploring the safety and efficacy of human adipose-derived stromal/stem cell (ASC) therapy in an established immunocompetent murine skin pressure ulcer model where dermal fibroblast cells (DFCs) served as a control. Human adipose tissue was processed using a closed system device designed for point-of-care use in the operating room and on file with the Food and Drug Administration. Cell characterization was performed using colony-forming unit-fibroblast, differentiation, and immunophenotypic assays in vitro. Wound healing was assessed over a 20-day period based on photomicrographs, histology, and immunohistochemistry. The isolated human ASCs displayed significantly greater colony formation relative to DFCs while both populations exhibited comparable immunophenotype and differentiation potential. Both fresh and cryopreserved human ASCs significantly accelerated and enhanced wound healing in young (2 month) mice of both sexes relative to DFC controls based on tissue architecture and CD68+ cell infiltration. In contrast, while injection of either fresh or cryopreserved human ASCs was safe in older mice, the fresh ASCs significantly enhanced wound closure relative to the cryopreserved ASCs. Overall, these findings support the safety and efficacy of human ASCs isolated using a closed system device designed for clinical procedures in the future treatment of pressure injuries.

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.

Fate of systemically and locally administered adipose-derived mesenchymal stromal cells and their effect on wound healing.

There is increasing interest in the use of adipose‐derived mesenchymal stromal cells (ASCs) for wound repair. As the fate of administered cells is still poorly defined, we aimed to establish the location, survival, and effect of ASCs when administered either systemically or locally during wound repair under physiological conditions. To determine the behavior of ASCs, a rat model with wounds on the dorsal aspect of the hind paws was used and two treatment modes were assessed: ASCs administered systemically into the tail vein or locally around the wound. ASCs were transduced to express both firefly luciferase (Fluc) and green fluorescent protein to enable tracking by bioluminescence imaging and immunohistological analysis. Systemically administered ASCs were detected in the lungs 3 hours after injection with a decrease in luminescent signal at 48 hours and signal disappearance from 72 hours. No ASCs were detected in the wound. Locally administered ASCs remained strongly detectable for 7 days at the injection site and became distributed within the wound bed as early as 24 hours post injection with a significant increase observed at 72 hours. Systemically administered ASCs were filtered out in the lungs, whereas ASCs administered locally remained and survived not only at the injection site but were also detected within the wound bed. Both treatments led to enhanced wound closure. It appears that systemically administered ASCs have the potential to enhance wound repair distally from their site of entrapment in the lungs whereas locally administered ASCs enhanced wound repair as they became redistributed within the wound bed.

Establishment and initial characterization of a simple 3D wound healing model

Abstract Poor wound healing as consequence of malfunctions in the regulation of the healthy tissue repair response affects millions of people worldwide. The number of therapies available to successfully treat chronic wound is still very limited and their development is costly and time consuming. Therefore simple to use 3D systems, reflecting the in vivo tissue complexity, are urgently needed. We introduce a novel 3D organotypic model (OTC) containing the major cell components active during wound healing i.e. keratinocytes, fibroblasts and inflammatory cells that allows to determine the effects of different therapeutic approaches on wound closure, cell differentiation and cytokine secretion in chronic wounds. There are first reports on irradiation with visible light of different wave length (Low Level Light Therapy) as a means to enhance wound closure. However the mechanisms underlying this therapy as well as optimized irradiation wavelength and dose are not clear and were therefore analyzed using our 3D organotypic model. In the standardized OTC model we could demonstrate epithelial closure under control conditions as well as differential effects of red and blue light irradiation with respect to stability of the newly formed epithelium and time until epithelial closure. First results show differential cytokine profiles upon different wavelength irradiation e.g. high expression of TGF beta and IL-1 beta in red light irradiated cultures and increased GM-CSF expression in blue light irradiated and control cultures.

Novel Human Full-Thickness Three-Dimensional Nonkeratinized Mucous Membrane Model for Pharmacological Studies in Wound Healing

Introduction: Efforts are increasingly aiming to develop in vitro models that can provide effective alternatives to in vivo experiments. The main aim of this study was the establishment of an in vitro model of the nonkeratinized mucous membrane that can be used as a standardized tool to evaluate biological and therapeutic effects of pharmaceuticals for mucosal wound healing. Methods: We established a full-thickness in vitro model of the nonkeratinized mucous membrane. While histological examination was performed to assess morphological characteristics, we utilized gene expression profiling using microarray and qRT-PCR analyses to identify molecular effects of treatment with a dexpanthenol-containing ointment after laser wounding. Results: Performing histological and immunofluorescence analyses we proved that our model mimics the two distinctive layers of the mucous membrane – the stratified squamous epithelium and the lamina propria. We used this model to investigate molecular effects of a dexpanthenol-containing ointment that is commonly used for the wound treatment of mucous membranes. For that purpose, our model exhibits a unique feature in that dexpanthenol and proliferation-enhancing additives that may interfere with our studies are not required for the maintenance of the model culture. After setting standardized lesions with a nonsequential fractional ultrapulsed CO₂ laser, topical treatment with the dexpanthenol-containing ointment enhanced wound closure in the model compared to placebo and untreated controls. Furthermore, microarray analysis revealed that the treatment of the laser-wounded model with the dexpanthenol-containing ointment evoked an upregulated expression of various genes related to accelerated wound healing. Conclusion: Overall, we verified that this novel mucous membrane model can be utilized in future to monitor ex vivo effects of various topical therapies on mucosa morphology, physiology, and gene expression. Our findings confirm the potential of the model as an in vitro tool for the replacement of pharmacological in vivo studies regarding mucosal wound healing.

A biocompatible and easy-to-make polyelectrolyte dressing with tunable drug delivery properties for wound care

Chitosan (CS) is a biodegradable and biocompatible polysaccharide which displays immune-stimulatory effects and anti-bacterial properties to facilitate wound closure. Over the years, different CS-based dressings have been developed; however, most of them are not fully biodegradable due to the involvement of synthetic polymers during dressing fabrication. In addition, preparation of many of these dressings is laborious, and may impose damaging effects on fragile therapeutic molecules. The objective of this study is to address these problems by developing a tunable, biocompatible, and biodegradable CS-based dressing for wound treatment. The dressing is fabricated via electrostatic interactions between CS and carmellose (CM). Its swelling properties, erosion behavior, loading efficiency and drug release sustainability can be tuned by simply changing the CS/CM mass-to-mass ratio. Upon loaded with minocycline hydrochloride, the dressing effectively protects the wound in mice from infection and enhances wound closure. Regarding its high tunability and promising in vivo performance, our dressing warrants further development as a user-friendly dressing for use in wound care.

Microbiota metabolites SCFA stimulate epithelial migration to promote wound healing through MFGE8 and PAK1

Abstract How microbiota regulate intestinal homeostasis is still not completely understood. Emerging evidence indicates that gut microbiota metabolites play crucial roles in maintenance of intestinal homeostasis and regulation of Inflammatory Bowel Disease (IBD). Many patients with IBD are deficient in the microbial metabolites of dietary fibers, short chain fatty acids (SCFAs). To date, the evidence for use of SCFAs as a treatment for IBD has been inconsistent, highlighting the need for further investigation. In this study, we demonstrate that SCFAs promote intestinal epithelial cell (IEC) wound healing. Treatment of mouse and human IEC in vitro with the SCFAs acetate, propionate, and butyrate enhanced wound closure by promoting cell migration, which was independent of cell proliferation. Further analysis of random cell migration revealed that SCFAs increased cell speed, cell persistence, and consequently mean squared displacement. To investigate the mechanism of enhanced migration, we performed microarray of mouse-derived enteroids, which identified p21 activated kinase 1 (PAK1) and milk fat globule-EGF factor 8 (MFGE8), two genes implicated in tissue repair and motility, to be highly upregulated. We confirmed upregulation of MFGE8 and PAK1 via qRT-PCR and western blot. Inhibition of PAK1 and CRISPR knockout of MFGE8 abrogated the effects of SCFAs on migration. Lastly, the above effects were dependent upon SCFAs inhibition of histone deacetylases (HDAC), as treatment of IECs with the HDAC inhibitor, trichostatin A, fully recapitulated the effects of SCFAs on migration and expression of MFGE8 and PAK1. These findings elucidate a pathway in which SCFAs inhibition of histone deacetylases may enhance wound healing in IBD.

NOVEL REGULATION OF A PAR2‐MEDIATED CELLULAR MIGRATION PROGRAM BY PRO‐INFLAMMATORY CYTOKINES

BACKGROUNDMucosal healing is the gold standard for IBD therapy. However, the mechanisms that determine mucosal healing are complex and need to be better understood to explain why many patients fail to achieve this key goal of therapy. The inflammatory environment is characterized by the presence of several serine proteases that signal through the protease‐activated receptors (PARs). PAR2 is ubiquitously expressed in the epithelial cells of the intestinal mucosa and activation serves a protective role consistent with host defence and repair. While our preliminary findings indicate that activation of PAR2 enhances wound closure, we do not know the cellular mechanisms that underlie this response.We hypothesize that activation of PAR2 induces a cellular migration program in intestinal epithelial cells that enhances mucosal healing in the inflammatory milieu.METHODSCircular wounds were introduced in T84 colonic epithelial cells. Wounded monolayers were treated with the PAR2 activating peptide, 2‐furoyl‐LIGRLO (2fLI, 5 μM), or the control reverse‐sequence peptide, 2‐furoyl‐OLRGIL (2fO, 5 μM), and live cell imaging was utilized to record wound closure over a 24 hr period. In other experiments, a cytokine cocktail consisting of IFNγ (10 ng/mL) and TNFα (10 ng/mL), alone or in combination with 2fLI, was applied to wounded monolayers and wound closure assessed. Intracellular effects of PAR2 activation and cytokine treatment were evaluated by measuring phosphorylation of key canonical signaling proteins using the MSD multi‐plex ELISA array system. EdU staining, with or without Mitomycin C (MMC), an inhibitor of proliferation, was used to determine the effect of cellular proliferation on wound closure.RESULTSPAR2 activation by 2fLI promoted wound closure in a concentration‐dependent manner (0.1 μM – 10 μM) compared to 2fO controls at the 12 and 24 hr timepoints. Interestingly, co‐stimulation with 2fLI and the cytokine cocktail resulted in an enhanced wound closure response at the 12 and 24 hr timepoints that was significantly greater than individual treatments (p<0.001). Co‐stimulation activated the downstream intracellular targets ERK1/2 and JNK compared to 2fO (p<0.001), but this activation was not greater than stimulation with 2fLI or cocktail alone, suggesting that MAP kinase activation was not responsible for the enhanced effect. MMC pre‐treatment partially reduced wound closure caused by co‐stimulation with 2fLI/IFNγ/TNFα, indicating that the enhanced wound healing effect was due in part to increased proliferation.CONCLUSIONSThese data suggest that both PAR2 activation and cytokine treatment promote wound closure in vitro through both enhanced cell migration and proliferation. The enhanced wound healing response to PAR2 activation in the presence of pro‐inflammatory cytokines suggests that the inflammatory milieu is necessary to initiate a proper wound healing response.Support or Funding InformationCanadian Institutes of Health Research (CIHR)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Sapylin (OK-432) alters inflammation and angiogenesis in vivo and vitro

BackgroundThe occurrence of seroma formation and long-term wound healing remain challenging complications after modified radical mastectomy. Sapylin is a drug used to reduce seroma formation and enhance wound closure, but these results remain controversial. We aimed to investigate the potential mechanism. MethodsA prospective, consecutive cohort study included 120 patients diagnosed with breast cancer who underwent modified radical mastectomy was designed. Patients were randomized into two group, using or not using OK-432 (sixty patients per group) during surgeries. Patients’ drainage fluids were collected for three days after surgery. Inflammatory cytokines and chemokines were measured with ELISA assays. The proliferative, migratory, and angiogenic capacity of HUVEC and HFL1 cells HUVEC and HFL1 cells were measured after being treated with drainage fluids. ResultsOur clinic data showed that there was no statistical significance between the two groups in patient characteristics before surgery. However, the outcomes of patients in experimental group were significantly better than those in control group. In vitro studies, the results of ELISA assays showed that several cytokines, including IL-1a, IL-6, TGF-β1, bFGF and VEGF were increased in the drainage fluids treated with Sapylin. The proliferative, migratory, and angiogenic capacity of HUVEC and HFL1 cells were significantly enhanced after being treated with Sapylin group drainage fluids. ConclusionSapylin could stimulate the body to secrete a variety of cytokines to promote wound healing by promoting endothelial cell proliferation and migration, angiogenesis and by increasing fibroblast migration and collagen deposition.

Electrospun Silybin Enriched Scaffolds of Polyethylene Oxide as Wound Dressings: Enhanced Wound Closure, Reepithelization in Rat Excisional Wound Model

Abstract: Aim/ Background: Wounds are considered as a common health problem due to their considerable burden on social life. Polymeric nanofibers have attracted attention in wound dressings due to their large surface area, smaller size and biocompatibility. The objective of this research is to develop silybin loaded polymeric scaffolds and further to check its efficacy in wound healing. Materials and Methods: Silybin loaded polymeric scaffolds was developed using polyethylene oxide as a polymer and glutaraldehyde as a crosslinker by electrospinning technique. It was characterized for scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, swelling behavior, water uptake capacity and drug release kinetics. Further, in vivo studies were carried out on rats by excisional wound model. Histopathological studies were performed to investigate the healing process. Results: From the results of scanning electron microscopy, 3% Polyethylene oxide in dichloromethane: dimethyl formamide (8:2) mixture was selected for further characterization. Swelling index for prepared electrospun scaffolds was found to be 62.40%, whereas water uptake capacity was found to be 38.42%. Release kinetics suggested sustained release of silybin. The histopathological study indicated that silybin loaded scaffolds improved the results for granulation tissue score, wound maturity score, period of epithelisation and collagen distribution. Conclusion: It can be concluded that silybin enriched nanofibrous scaffold of polyethylene oxide is beneficial in topical applications to form the basis for new skin regenerating and wound healing. Key words: Nanofiber, Electrospinning, Scaffold, Silybin, Wound healing.

Synthesis, characterization, anti-proliferative and wound healing activities of silver nanoparticles synthesized from Caulerpa scalpelliformis

Abstract Green synthesis of silver nanoparticles is gaining momentum to avoid use of chemicals thus making eco-friendly approach. In continuation of our efforts to find effective alternative to chemical drugs, we have reported the C. scalpelliformis mediated synthesis of silver nanoparticles with biomedical properties. The green synthesized AgNPs also exhibited potent wound healing property by enhancing wound closure in an experimental rat model. Furthermore, the synthesized AgNPs also showed cytotoxic effects against MCF-7 cells, as exposure 40 μg/ml of AgNPs resulted in 50% cell death. This observed activity is mediated through modulating the mRNA level expression of Bax/ Bcl-2 and protein levels of caspase-3 and -9 in vitro. We are the first to report on anti-proliferative, pro-apoptotic effects and wound healing activity of AgNPs from C. scalpelliformis extract. The present study opens new avenues for use of AgNPs in various biomedical applications namely an anti-tumor agent and healing chronic and diabetic cutaneous wounds.

Engineering Bioactive Self-Healing Antibacterial Exosomes Hydrogel for Promoting Chronic Diabetic Wound Healing and Complete Skin Regeneration.

Rationale: Chronic nonhealing diabetic wound therapy and complete skin regeneration remains a critical clinical challenge. The controlled release of bioactive factors from a multifunctional hydrogel was a promising strategy to repair chronic wounds.Methods: Herein, for the first time, we developed an injectable, self-healing and antibacterial polypeptide-based FHE hydrogel (F127/OHA-EPL) with stimuli-responsive adipose-derived mesenchymal stem cells exosomes (AMSCs-exo) release for synergistically enhancing chronic wound healing and complete skin regeneration. The materials characterization, antibacterial activity, stimulated cellular behavior and in vivo full-thickness diabetic wound healing ability of the hydrogels were performed and analyzed.Results: The FHE hydrogel possessed multifunctional properties including fast self-healing process, shear-thinning injectable ability, efficient antibacterial activity, and long term pH-responsive bioactive exosomes release behavior. In vitro, the FHE@exosomes (FHE@exo) hydrogel significantly promoted the proliferation, migration and tube formation ability of human umbilical vein endothelial cells (HUVECs). In vivo, the FHE@exo hydrogel significantly enhanced the healing efficiency of diabetic full-thickness cutaneous wounds, characterized with enhanced wound closure rates, fast angiogenesis, re-epithelization and collagen deposition within the wound site. Moreover, the FHE@exo hydrogel displayed better healing outcomes than those of exosomes or FHE hydrogel alone, suggesting that the sustained release of exosomes and FHE hydrogel can synergistically facilitate diabetic wound healing. Skin appendages and less scar tissue also appeared in FHE@exo hydrogel treated wounds, indicating its potent ability to achieve complete skin regeneration.Conclusion: This work offers a new approach for repairing chronic wounds completely through a multifunctional hydrogel with controlled exosomes release.

Histological Survey of the Effect of Granulocyte-colony-stimulating Factor(G-CSF) on Bacterial Translocation and Wound Healing in Burned Mice

Background: Burn wound is an important cause of morbidity and mortality worldwide. Improving the host's immune system and removing the infection can be effective in healing wounds caused by burns. Granulocyte-colony-stimulating factor (G-CSF) stimulates both the bone marrow to produce granulocytes and the function of neutrophil precursors. The aim of this study was to examine the effect of G-CSF on removing infection and healing wound. Materials and Methods: A burn model was used to induce burns in 18 adult Balb/c mice, and their wounds were infected by Acinetobacter baumannii strains. Burned mice were divided into two groups (control and G-CSF) and treated daily by subcutaneous injections of normal saline (0.1 mL) and G-CSF (10 I¼g/kg). The wound healing process was evaluated by the morphological and histological assessments. Results: In morphological assay, the mean size of the wounds in the 3rd and 7th days of the treatment was significantly lower in the G-CSF treated group compared to the control group. Some of the histological parameters were evaluated, including the level of inflammation, re-epithelialization, angiogenesis, collagen deposition, the amount of granulation tissue, and fibroblast maturation. The results showed that inflammation was reduced in the G-CSF-treated group, and re-epithelialization and collagen deposition were increased insignificantly compared to the normal saline-treated group. Furthermore, bacterial translocation was reduced significantly in the G-CSF-treated group. Conclusion: G-CSF enhances wound closure and helps in wound healing by improving the immune system. It has also an anti-inflammatory role and reduces bacterial translocation.

Curcumin promotes burn wound healing in mice by upregulating caveolin-1 in epidermal stem cells.

We aimed to explore the effect of curcumin on epidermal stem cells (ESCs) in regulating wound healing and the underlying molecular mechanism. We treated mouse ESCs isolated from skin tissues with curcumin, and then assessed the proliferation ability of cells induced by epidermal growth factor using cell counting kit-8 assay. The pluripotency of ESCs was evaluated as well through examination of Nanog expression in ESCs. Further, mice with skin burns were treated with ESCs with or without curcumin pretreatments. Histological evaluations were then preformed to determine wound scores, cell proliferation, reepithelialization, and capillary density in wounds. Curcumin treatment promoted the proliferative ability of ESCs and conditioned medium from curcumin-treated ESCs enhanced human umbilical vein endothelial cell (HUVEC) tube formation. We also found curcumin treatment elevated caveolin-1 expression in ESCs, which was required for the beneficial effect of curcumin on ESC proliferation and HUVEC tube formation. Next, using a mouse model of burn wound healing, curcumin-treated ESCs exhibited enhanced wound closure, which also required caveolin-1 expression. Our current study demonstrates the beneficial effect of curcumin on burn wound healing in mice, which is mediated by upregulating caveolin-1 in ESCs, and supports the potential therapeutic role of curcumin in ESC-based treatment against skin wound healing.

Bee venom improves diabetic wound healing by protecting functional macrophages from apoptosis and enhancing Nrf2, Ang-1 and Tie-2 signaling

Impaired wound healing is a serious complication of diabetes that negatively affects the patient’s socioeconomic life. Multiple mechanisms contribute to impaired diabetic wound healing including deficient recruitment of wound macrophages/neutrophils and impaired neovascularization. Bee venom (BV) has been used as an anti-inflammatory agent for the treatment of several diseases. Nevertheless, the impacts of BV on the diabetic wound healing have been poorly studied. In the present study, we investigated the molecular mechanisms underlying BV treatment on diabetic wound healing in a type I diabetic mouse model. Three experimental groups were used: group 1, non-diabetic control mice; group 2, vehicle-diabetic mice; and group 3, BV-treated diabetic mice. We found that the diabetic mice exhibited impaired wound closure characterized by a significant decrease in collagen and β-defensin-2 (BD-2) expression compared to control non-diabetic mice. The impairment of diabetic wound healing is attributed to increased ROS levels and abolished antioxidant enzymes activity in the wounded tissues. Additionally, wounded tissue in diabetic mice revealed aberrantly decreased levels of Ang-1 and Nrf2 (the agonist ligands of Tie-2) followed by a marked reduction in the phosphorylation of Tie2 and downstream signaling eNOS, AKT and ERK. Impaired diabetic wound healing was also characterized by a significant reduction in activities of total antioxidant enzymes followed by a marked reduction in the levels of CCL2, CCL3 and CXCL2; which led to impaired recruitment and functions of wound macrophages/neutrophils; and significant reduction in the expression of CD31, a marker for neovascularization and angiogenesis of the injured tissue. Interestingly, BV treatment significantly enhanced wound closure in diabetic mice by increasing collagen and BD-2 expression and restoring the levels of Ang-1 and Nrf2 and hence enhancing the Tie-2 downstream signaling. Most importantly, treatment of diabetic mice with BV significantly restored the activities of wounded tissue antioxidant enzymes and the levels of chemokines, and subsequently rescued wound macrophages from mitochondrial membrane potential-induced apoptosis. Our findings reveal the immune-enhancing effects of BV for improving healing process of diabetic wounds and provide the first insight concerning the underlying molecular mechanisms.