Stimulated Wound Closure Research Articles

Antihistamine and Wound Healing Potential of Gold Nanoparticles Synthesized Using Bulbine frutescens (L.) Willd.

Atopic dermatitis (eczema) is an inflammatory skin condition with synthetic treatments that induce adverse effects and are ineffective. One of the proposed causes for the development of the condition is the outside-in hypothesis, which states that eczema is caused by a disruption in the skin barrier. These disruptions include developing dry cracked skin, which promotes the production of histamine. Bulbine frutescens (BF) is traditionally used to treat wounds and eczema; however, limited research has been conducted to scientifically validate this. Furthermore, gold nanoparticles (AuNPs) have been used to repair damaged skin; however, no research has been conducted on AuNPs synthesized using BF. The study aimed to determine whether BF alleviated skin damage through wound healing, reducing the production of histamine and investigate whether AuNPs synthesized using BF would enhance biological activity. Four extracts and four synthesized AuNPs were prepared using BF and their antiproliferative and wound healing properties against human keratinocyte cells (HaCaT) were evaluated. Thereafter, the selected samples antiproliferative activity and antihistamine activity against phorbol 12-myristate 13-acetate (PMA) stimulated granulocytes were evaluated. Of the eight samples, the freeze-dried leaf juice (BFE; p < 0.01) extract and its AuNPs (BFEAuNPs; p < 0.05) displayed significant wound closure at 100 µg/mL and were further evaluated. The selected samples displayed a fifty percent inhibitory concentration (IC50) of >200µg/mL against PMA stimulated granulocytes. Compared to the untreated (media with PMA) control (0.30 ± 0.02ng/mL), BFEAuNPs significantly inhibited histamine production at a concentration of 100 (p < 0.01) and 50 µg/mL (p < 0.001). BFE and BFEAuNPs stimulated wound closure, while BFEAuNPs significantly inhibited histamine production. Further investigation into BFEAuNPs in vivo wound healing activity and whether it can target histamine-associated receptors on mast cells as a potential mechanism of action should be considered.

Glycomacropeptide Protects against Inflammation and Oxidative Stress, and Promotes Wound Healing in an Atopic Dermatitis Model of Human Keratinocytes.

Keratinocytes are actively implicated in the physiopathology of atopic dermatitis (AD), a skin allergy condition widely distributed worldwide. Glycomacropeptide (GMP) is a milk-derived bioactive peptide generated during cheese making processes or gastric digestion. It has antiallergic and skin barrier restoring properties when it is orally administered in experimental AD. This study aimed to evaluate the effect of GMP on the inflammatory, oxidative, proliferative, and migratory responses of HaCaT keratinocytes in an in vitro AD model. GMP protected keratinocytes from death and apoptosis in a dose dependent manner. GMP at 6.3 and 25 mg/mL, respectively, reduced nitric oxide by 50% and 83.2% as well as lipid hydroperoxides by 27.5% and 45.18% in activated HaCaT cells. The gene expression of TSLP, IL33, TARC, MDC, and NGF was significantly downregulated comparably to control by GMP treatment in activated keratinocytes, while that of cGRP was enhanced. Finally, in an AD microenvironment, GMP at 25 mg/mL stimulated HaCaT cell proliferation, while concentrations of 0.01 and 0.1 mg/mL promoted the HaCaT cell migration. Therefore, we demonstrate that GMP has anti-inflammatory and antioxidative properties and stimulates wound closure on an AD model of keratinocytes, which could support its reported bioactivity in vivo.

Phytohustil® and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve the migratory capacity of endothelial cells in vitro.

Introduction: Althaea officinalis L.'s root extract (REA) has been used as a medicinal plant since ancient times to treat a cough. Applying REA leads to a protective film that induces a faster regeneration of the lesioned laryngopharyngeal mucosa caused by dry coughs. The buccopharyngeal mucosa is a highly vascularized tissue. In this regard, anti-inflammatory/-oxidant phytochemicals that improve the repair of the lesion site, e.g., neovascularization in the wound, are critical for promoting healing. For this reason, it is essential to investigate the effects of Phytohustil® and REA on different cellular components of the mucosa under conditions similar to those found in the injured mucosa. Thus, this in vitro study investigated the anti-inflammatory/oxidative and pro-migratory properties of Phytohustil® cough syrup on vascular endothelial cells. Methods: Human umbilical vein endothelial cells (HUVEC) were pretreated (24h) with Phytohustil®, its excipients, or REA, followed by incubation with hydrogen peroxide (H2O2; 1h; pro-oxidative) or with lipopolysaccharides (LPS; 3h; pro-inflammatory). Viability and cytotoxicity were measured by PrestoBlue® assay. Intracellular reactive oxygen species (ROS) were quantified with 20-70-dichlorofluorescein diacetate (DCFDA). The release of interleukin 6 (IL6) was determined by enzyme-linked immunosorbent assay (ELISA). The migratory capacity of HUVEC was measured using a scratch assay. Results: Our results show that Phytohustil®, its excipients and REA were not cytotoxic. Pretreatment of HUVEC (24h) with Phytohustil® or REA inhibited the LPS-activated IL6 release. Phytohustil® or REA inhibited the H2O2-induced cytotoxicity and intracellular ROS production. Phytohustil® and REA significantly stimulated wound closure compared to the control. Conclusion: Our data show that Phytohustil® and REA have anti-inflammatory/-oxidant properties and improve the migratory capacity of vascular endothelial cells. These properties may contribute to the healing characteristics of Phytohustil® and support the benefit of Phytohustil® in patient's treatment of irritated oral mucosa.

ZINC40099027 promotes monolayer circular defect closure by a novel pathway involving cytosolic activation of focal adhesion kinase and downstream paxillin and ERK1/2.

ZINC40099027 (ZN27) is a specific focal adhesion kinase (FAK) activator that promotes murine mucosal wound closure after ischemic or NSAID-induced injury. Diverse motogenic pathways involve FAK, but the direct consequences of pure FAK activation have not been studied, and how ZN27-induced FAK activation stimulates wound closure remained unclear. We investigated signaling and focal adhesion (FA) turnover after FAK activation by ZN27 in Caco-2 cells, confirming key results in CCD841 cells. ZN27 increased Caco-2 FAK-Y-397, FAK-Y-576/7, paxillin-Y-118, and ERK 1/2 phosphorylation and decreased FAK-Y-925 phosphorylation, without altering FAK-Y-861, p38, Jnk, or Akt phosphorylation. ZN27 increased FAK-paxillin interaction while decreasing FAK-Grb2 association. ZN27 increased membrane-associated FAK-Y-397 and FAK-Y-576/7 phosphorylation and paxillin-Y-118 and ERK 1/2 phosphorylation but decreased FAK-Y-925 phosphorylation without altering Src or Grb2. Moreover, ZN27 increased the fluorescence intensity of GFP-FAK and pFAK-Y397 in FAs and increased the total number of FAs but reduced their size in GFP-FAK-transfected Caco-2 cells, consistent with increased FA turnover. In contrast, FAK-Y397F transfection prevented ZN27 effects on FAK size and number and FAK and pFAK fluorescent intensity in FAs. We confirmed the proposed FAK/paxillin/ERK pathway using PP2 and U0126 to block Src and MEK1/2 in Caco-2 and CCD841 cells. These results suggest that ZN27 promotes intestinal epithelial monolayer defect closure by stimulating autophosphorylation of FAK in the cytosol, distinct from classical models of FAK activation in the FA. Phosphorylated FAK translocates to the membrane, where its downstream substrates paxillin and ERK are phosphorylated, leading to FA turnover and human intestinal epithelial cell migration.

The activity of Aloe arborescens Miller varieties on wound-associated pathogens, wound healing and growth factor production

Various Aloe L. species have been used worldwide to soothe and treat dermal wounds and burns. However, there is a lack of substantiative research on the efficacy of Aloe L. species for wound healing. The aim of this study was to investigate the differences in biological activities of the gel and ethanolic (EtOH) leaf extracts of seven Aloe arborescens Miller varieties. The extracts were investigated for their antibacterial activity against wound-associated bacteria, Staphylococcus aureus (ATCC 6538 and ATCC 25293) and Pseudomonas aeruginosa (ATCC 9027), as well as their nitric oxide (NO) scavenging potential. Varieties with antibacterial activity were further evaluated for wound closure and growth factor stimulation in human keratinocytes (HaCaT). The EtOH leaf extract of the ‘Eloff’ and ‘Jack Marais’ varieties displayed antibacterial activity against S. aureus ATCC 25293 (MIC of 500 and 250 μg/mL, respectively). The EtOH leaf extract of ‘Jack Marais’ displayed an MIC of 500 μg/mL against S. aureus ATCC 6538. The gel extract of ‘Le Roux’ exhibited antioxidant activity with a half maximal inhibitory concentration (IC50 of 2696 ± 582.66 μg/mL). The EtOH leaf extracts of ‘Eloff’ and ‘Jack Marais’ showed significant (p < 0.05) wound closure of 56.06 ± 1.47 and 73.72 ± 0.65%, respectively at 50 μg/mL and the ‘Jack Marais’ gel extract significantly stimulated wound closure (p < 0.05) by 77.02 ± 1.97 and 71.51 ± 1.11% at 50 and 100 μg/mL, respectively. Both the ‘Jack Marais’ gel extract (at 50 and 100 μg/mL) and the EtOH leaf extract (50 μg/mL), significantly (p < 0.05) increased platelet-derived growth factor (PDGF-AA) secretion to 601.09 ± 97.77, 1035.00 ± 913.98 and 559.43 ± 112.52 pg/mL, respectively. The ‘Jack Marais’ EtOH leaf extract exhibited the highest antibacterial activity, whereas the gel extract displayed the greatest potential to stimulate wound closure. This not only suggests a difference in biological activity among varieties but also between the type of extract (gel or leaf).

Hair Follicle Grafting Therapy Promotes Re-Emergence of Critical Skin Components in Chronic Nonhealing Wounds

An exploding public health crisis is the exponential growth in the incidence of chronic nonhealing ulcers associated with diseases such as diabetes. Various modalities have been developed to stimulate wound closure that is otherwise recalcitrant to standard clinical treatments. However, these approaches primarily focus on the process of re-epithelialization and are often deficient in regenerating the full spectrum of structures necessary for normal skin function. Autologous hair follicle grafting is a recent therapy to stimulate the closure of such nonhealing wounds, and we observed effects beyond the epidermis to other important components of the dermis. We found that hair follicle grafting facilitated the reappearance of various undifferentiated and differentiated layers of the epidermis with the restoration of epidermal junctions. In addition, other important structures that are critical for cutaneous health and function such as the blood and lymph vasculature, nerve fibers, and sweat gland structures were restored in postgrafted wounds. Interestingly, both immune cells and inflammatory signals were substantially decreased, indicating a reduction in the chronic inflammation that is a hallmark of nonhealing wounds. Our observation that punch wounds created on the postgrafted area likewise healed suggests that this is a self-sustaining long-term therapy for patients with chronic wounds.

Early results of negative pressure wound therapy in treatment of chronic wounds

Abstract Background Chronic wounds may affect only the epidermis and dermis, or they may affect tissues all the way to the fascia. Chronic wounds seem to be detained in one or more of the phases of wound healing. For example, chronic wounds often remain in the inflammatory stage for too long. Aim of the work to assess the effect of negative pressure wound therapy in management of chronic wound. Patients and Methods This is prospective study was conducted on 30 Egyptian volunteers participated; they were 20 males and 10 females, between the age of 18 and 70 years. This study was conducted from July 2017 to July 2018 at Ain shams university specialized hospitals and Alexandria armed forces hospital. Results VAC therapy, together with periodical surgical wound debridement and specific antibiotic therapy, could be helpful to promote and accelerate wound healing of foot lesions after restoration of an adequate distal blood flow through surgical revascularization or angioplasty. Conclusion Negative-pressure wound therapy (NPWT) devices are designed to apply controlled suction to a wound bed at continuous or intermittent pressure settings to stimulate wound closure. Negative pressure can result in numerous alterations in the wound environment, including removal of excess exudate containing high concentrations of proteases and inflammatory cytokines, stimulation of senescent cells, mobilization of macrophages, and stimulation of angiogenesis.

Small molecule FAK activator promotes human intestinal epithelial monolayer wound closure and mouse ulcer healing

GI mucosal healing requires epithelial sheet migration. The non-receptor tyrosine kinase focal adhesion kinase (FAK) stimulates epithelial motility. A virtual screen identified the small drug-like FAK mimic ZINC40099027, which activates FAK. We assessed whether ZINC40099027 promotes FAK-Tyr-397 phosphorylation and wound healing in Caco-2 monolayers and two mouse intestinal injury models. Murine small bowel ulcers were generated by topical serosal acetic acid or subcutaneous indomethacin in C57BL/6J mice. One day later, we began treatment with ZINC40099027 or DMSO, staining the mucosa for phosphorylated FAK and Ki-67 and measuring mucosal ulcer area, serum creatinine, ALT, and body weight at day 4. ZINC40099027 (10–1000 nM) dose-dependently activated FAK phosphorylation, without activating Pyk2-Tyr-402 or Src-Tyr-419. ZINC40099027 did not stimulate proliferation, and stimulated wound closure independently of proliferation. The FAK inhibitor PF-573228 prevented ZINC40099027-stimulated wound closure. In both mouse ulcer models, ZINC40099027accelerated mucosal wound healing. FAK phosphorylation was increased in jejunal epithelium at the ulcer edge, and Ki-67 staining was unchanged in jejunal mucosa. ZINC40099027 serum concentration at sacrifice resembled the effective concentration in vitro. Weight, creatinine and ALT did not differ between groups. Small molecule FAK activators can specifically promote epithelial restitution and mucosal healing and may be useful to treat gut mucosal injury.

IL-1β–Primed Mesenchymal Stromal Cells Improve Epidermal Substitute Engraftment and Wound Healing via Matrix Metalloproteinases and Transforming Growth Factor-β1

Since the 1980s, deep and extensive skin wounds and burns are treated with autologous split-thickness skin grafts, or cultured epidermal autografts, when donor sites are limited. However, the clinical use of cultured epidermal autografts often remains unsatisfactory because of poor engraftment rates, altered wound healing, and reduced skin functionality. In the past few decades, mesenchymal stromal cells (MSCs) have raised much attention because of their anti-inflammatory, protrophic, and pro-remodeling capacities. More specifically, gingival MSCs have been shown to possess enhanced wound healing properties compared with other tissue sources. Growing evidence also indicates that MSC priming could potentiate therapeutic effects in diverse invitro and invivo models of skin trauma. In this study, we found that IL-1β-primed gingival MSCs promoted cell migration, dermal-epidermal junction formation, and inflammation reduction invitro, as well as improved epidermal substitute engraftment invivo. IL-1β-primed gingival MSCs had different secretory profiles from naive gingival MSCs, characterized by an overexpression of transforming growth factor-β and matrix metalloproteinase (MMP) pathway agonists. Eventually, MMP-1, MMP-9, and transforming growth factor-β1 appeared to be critically involved in IL-1β-primed gingival MSC mechanisms of action.

Periostin and CCN2 Scaffolds Promote the Wound Healing Response in the Skin of Diabetic Mice.

Nonhealing skin wounds remain a significant burden on health care systems, with diabetic patients 20 times as likely to undergo a lower extremity amputation due to impaired healing. Novel treatments that suppress the proinflammatory signature and induce the proliferative and remodeling phases are needed clinically. We demonstrate that the addition of periostin and CCN2 in a scaffold form increases closure rates of full-thickness skin wounds in diabetic mice, concomitant with enhanced angiogenesis. Our results demonstrate the efficacy of periostin- and CCN2-containing biomaterials to stimulate wound closure, which could represent a novel method for the treatment of diabetic skin wounds.

A dual deformable liposomal ointment functionalized with retinoic acid and epidermal growth factor for enhanced burn wound healing therapy.

An ointment containing retinoic acid deformable liposomes (TRA DLs) and epidermal growth factor cationic deformable liposomes (EGF CDLs) was prepared for the treatment of deep partial-thickness burns. The characterization tests confirmed both liposomes featured small particle sizes, high drug entrapment efficiencies and sustained drug release behavior. Compared with the free drug, TRA DLs and EGF CDLs exhibited superior skin permeation and remarkably increased drug deposition by 2.9 and 18.8 folds, respectively. Results on HaCaT cells indicated the combined application of two liposomes exerted a synergistic effect and prominently promoted cell proliferation and migration. Application of the dual liposomal ointment on a deep partial-thickness burn model stimulated wound closure (p < 0.001), promoted skin appendage formation and increased collagen production, thus improving healing quality. Finally, it was demonstrated that TRA significantly up-regulated the expression of EGFR and HB-EGF to enhance the therapeutic effect of EGF. Therefore, the dual liposomal ointment is a promising topical therapeutic for burn treatment.

Does blue light restore human epidermal barrier function via activation of Opsin during cutaneous wound healing?

Visible light has beneficial effects on cutaneous wound healing, but the role of potential photoreceptors in human skin is unknown. In addition, inconsistency in the parameters of blue and red light-based therapies for skin conditions makes interpretation difficult. Red light can activate cytochrome c oxidase and has been proposed as a wound healing therapy. UV-blue light can activate Opsin 1-SW, Opsin 2, Opsin 3, Opsin 4, and Opsin 5 receptors, triggering biological responses, but their role in human skin physiology is unclear. Localization of Opsins was analyzed in situ in human skin derived from face and abdomen by immunohistochemistry. An ex vivo human skin wound healing model was established and expression of Opsins confirmed by immunohistochemistry. The rate of wound closure was quantitated after irradiation with blue and red light and mRNA was extracted from the regenerating epithelial tongue by laser micro-dissection to detect changes in Opsin 3 (OPN3) expression. Retention of the expression of Opsins in primary cultures of human epidermal keratinocytes and dermal fibroblasts was confirmed by qRT-PCR and immunocytochemistry. Modulation of metabolic activity by visible light was studied. Furthermore, migration in a scratch-wound assay, DNA synthesis and differentiation of epidermal keratinocytes was established following irradiation with blue light. A role for OPN3 in keratinocytes was investigated by gene silencing. Opsin receptors (OPN1-SW, 3 and 5) were similarly localized in the epidermis of human facial and abdominal skin in situ. Corresponding expression was confirmed in the regenerating epithelial tongue of ex vivo wounds after 2 days in culture, and irradiation with blue light stimulated wound closure, with a corresponding increase in OPN3 expression. Expression of Opsins was retained in primary cultures of epidermal keratinocytes and dermal fibroblasts. Both blue and red light stimulated the metabolic activity of cultured keratinocytes. Low levels of blue light reduced DNA synthesis and stimulated differentiation of keratinocytes. While low levels of blue light did not alter keratinocyte migration in a scratch wound assay, higher levels inhibited migration. Gene silencing of OPN3 in keratinocytes was effective (87% reduction). The rate of DNA synthesis in OPN3 knockdown keratinocytes did not change following irradiation with blue light, however, the level of differentiation was decreased. Opsins are expressed in the epidermis and dermis of human skin and in the newly regenerating epidermis following wounding. An increase in OPN3 expression in the epithelial tongue may be a potential mechanism for the stimulation of wound closure by blue light. Since keratinocytes and fibroblasts retain their expression of Opsins in culture, they provide a good model to investigate the mechanism of blue light in wound healing responses. Knockdown of OPN3 led to a reduction in early differentiation of keratinocytes following irradiation with blue light, suggesting OPN3 is required for restoration of the barrier function. Understanding the function and relationship of different photoreceptors and their response to specific light parameters will lead to the development of reliable light-based therapies for cutaneous wound healing. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.

Micelle-Coated, Hierarchically Structured Nanofibers with Dual-Release Capability for Accelerated Wound Healing and Infection Control.

Tailoring nanofibrous matrices-a material with much promise for wound healing applications-to simultaneously mitigate bacterial colonization and stimulate wound closure of infected wounds is highly desirable. To that end, a dual-releasing, multiscale system of biodegradable electrospun nanofibers coated with biocompatible micellar nanocarriers is reported. For wound healing, transforming growth factor-β1 is incorporated into polycaprolactone/collagen (PCL/Coll) nanofibers via electrospinning and the myofibroblastic differentiation of human dermal fibroblasts is locally stimulated. To prevent infection, biocompatible nanocarriers of polypeptide-based block copolymer micelles are deposited onto the surfaces of PCL/Coll nanofibers using tannic acid as a binding partner. Micelle-modified fibrous scaffolds are favorable for wound healing, not only supporting the attachment and spreading of fibroblasts comparable to those on noncoated nanofibers, but also significantly enhancing fibroblast migration. Micellar coatings can be loaded with gentamicin or clindamycin and exhibit antibacterial activity as measured by Petrifilm and zone of inhibition assays as well as time-dependent reduction of cellular counts of Staphylococcus aureus cultures. Moreover, delivery time of antibiotic dosage is tunable through the application of a novel modular approach. Altogether, this system holds great promise as an infection-mitigating, cell-stimulating, biodegradable skin graft for wound management and tissue engineering.

Maltodextrin/ascorbic acid stimulates wound closure by increasing collagen turnover and TGF-β1 expression in vitro and changing the stage of inflammation from chronic to acute in vivo

It has been reported that carbohydrates confer physicochemical properties to the wound environment that improves tissue repair. We evaluated in vitro and in vivo wound healing during maltodextrin/ascorbic acid treatment. In a fibroblast monolayer scratch assay, we demonstrated that maltodextrin/ascorbic acid stimulated monolayer repair by increasing collagen turnover coordinately with TGF-β1 expression (rising TGF-β1 and MMP-1 expression, as well as gelatinase activity, while TIMP-1 was diminished), similar to in vivo trends. On the other hand, we observed that venous leg ulcers treated with maltodextrin/ascorbic acid diminished microorganism population and improved wound repair during a 12 week period. When maltodextrin/ascorbic acid treatment was compared with zinc oxide, almost four fold wound closure was evidenced. Tissue architecture and granulation were improved after the carbohydrate treatment also, since patients that received maltodextrin/ascorbic acid showed lower type I collagen fiber levels and increased extracellular alkaline phosphatase activity and blood vessels than those treated with zinc oxide. We hypothesize that maltodextrin/ascorbic acid treatment stimulated tissue repair of chronic wounds by changing the stage of inflammation and modifying collagen turnover directly through fibroblast response.

Platelet-Rich Plasma for the Treatment of Clean Diabetic Foot Ulcers

Diabetic foot ulcer is considered as a major health problem that predisposes to limb amputation. Among the different methods to achieve ulcer healing, platelet-rich plasma (PRP) gel is gaining popularity. It is thought to stimulate wound closure by providing essential growth factors for healing. This study aims to evaluate the value of autologous PRP gel in the treatment of diabetic ulcers. The study included 56 patients of both sex from 18 to 80years, with clean chronic diabetic foot ulcers divided into 2 equal groups. The first group was treated by antiseptic ointment dressing, and the second group was treated by autologous platelet gel. PRP together with thrombin were prepared by centrifugation at each dressing session. Thrombin and calcium chloride were used to activate the PRP. The formed platelet gel was applied to the wound twice weekly. Statically significant increase in healing rate was found in the PRP-treated group, and complete healing was achieved in 86% of them in comparison to 68% of the control group. In the study group, rate of healing per week was greater during the first 8weeks and starts to decline afterward. The use of platelet gel showed a lower rate of wound infection. Autologous platelet gel is more effective than the local antiseptic dressing in terms of healing rate and prevention of infection in clean diabetic ulcers.

Identification and Characterization of Novel Matrix-Derived Bioactive Peptides: A Role for Collagenase from Santyl® Ointment in Post-Debridement Wound Healing?

Debridement, the removal of diseased, nonviable tissue, is critical for clinicians to readily assess wound status and prepare the wound bed for advanced therapeutics or downstream active healing. Removing necrotic slough and eschar through surgical or mechanical methods is less specific and may be painful for patients. Enzymatic debridement agents, such as Clostridial collagenase, selectively and painlessly degrade devitalized tissue. In addition to its debriding activities, highly-purified Clostridial collagenase actively promotes healing, and our past studies reveal that extracellular matrices digested with this enzyme yield peptides that activate cellular migratory, proliferative and angiogenic responses to injury in vitro, and promote wound closure in vivo. Intriguingly, while collagenase Santyl® ointment, a sterile preparation containing Clostridial collagenases and other non-specific proteases, is a well-accepted enzymatic debridement agent, its role as an active healing entity has never been established. Based on our previous studies of pure Clostridial collagenase, we now ask whether the mixture of enzymes contained within Santyl® produces matrix-derived peptides that promote cellular injury responses in vitro and stimulate wound closure in vivo. Here, we identify novel collagen fragments, along with collagen-associated peptides derived from thrombospondin-1, multimerin-1, fibronectin, TGFβ-induced protein ig-h3 and tenascin-C, generated from Santyl® collagenase-digested human dermal capillary endothelial and fibroblastic matrices, which increase cell proliferation and angiogenic remodeling in vitro by 50–100% over controls. Using an established model of impaired healing, we further demonstrate a specific dose of collagenase from Santyl® ointment, as well as the newly-identified and chemically-synthesized ECM-derived peptides significantly increase wound re-epithelialization by 60–100% over saline-treated controls. These results not only confirm and extend our earlier studies using purified collagenase- and matrix-derived peptides to stimulate healing in vitro and in vivo, but these Santyl®-generated, matrix-derived peptides may also represent exciting new opportunities for creating advanced wound healing therapies that are enabled by enzymatic debridement and potentially go beyond debridement.

Amelioration of excision wounds by topical application of green synthesized, formulated silver and gold nanoparticles in albino Wistar rats

Wound healing, a complex biological process, has attained a lot of attention as dermatologists are primarily interested in stimulated wound closure without formation of scar or a faint scar. The recent upsurgence of nanotechnology has provided novel therapeutic materials in the form of silver and gold nanoparticles which accelerate the wound healing process. The effect of formulated nanoparticles using Coleus forskohlii root extract (green synthesized) has been tried out for ameliorating full thickness excision wounds in albino Wistar male rats. The evaluation of in vivo activity of nanoparticles in wound healing was carried out on open wounds made by excision on the dorsal sides of albino Wistar rats under anesthesia, and the healing of the wounds was assessed. Histological aspects of the healing process were studied by a HE (Hematoxylin and Eosin) staining method to assess various degrees of re-epithelialization and the linear alignment of the granulation tissue whereas Van Gieson's histochemical staining was performed to observe collagen fibers. The healing action shown by the formulated nanoparticles was remarkable during the early stages of wound healing, which resulted in the substantial reduction of the whole healing period. Topical application of formulated gold nanoparticles was found to be more effective in suppressing inflammation and stimulating re-epithelialization compared to silver nanoparticles during the healing process. The results throw light on the amelioration of excision wounds using nanoparticles which could be a novel therapeutic way of improving wound healing in clinical practice. The mechanism of advanced healing action of both types of nanoparticles could be due to their antimicrobial, antioxidant and anti-inflammatory properties.

1′‐Acetoxychavicol acetate accelerates human skin wound healing

IntroductionChronic wounds are recently increasing in number among diabetic or bedridden person. It is important to find effective treatments for them. 1′‐acetoxychavicol acetate (ACA) is the compound obtained from ginger family such as Alpinia galangal. ACA has been reported to have various physiological effects, anti‐cancer, anti‐obesity, and anti‐oxidant. Here, we focus on the effect of ACA on wound healing.MethodsWe performed scratch assay in the presence of mitomycin‐C to block HaCaT keratinocytes (KCs) cell proliferation. We performed an in vitro scratch assay with MEK/ERK inhibitor (U0126) or PI3K inhibitor (LY294002), to examine how the inhibition of MEK/ERK or PI3K affects HaCaT KCs migration. Furthermore, we performed human wounded skin organ culture with ACA. We measured the length of epithelial tongue.ResultsACA significantly promoted wound closure in the presence of mitomycin‐C. This result showed that ACA stimulates HaCaT KCs migration without modifying proliferation. MEK/ERK or PI3K‐inhibited HaCaT KCs in the presence of ACA showed a reduction of migration as compared to the ACA alone treated cells. These results suggest that ACA could promote wound closure via inducing ERK/MAPK and PI3K activity. Furthermore, ACA stimulated human skin re‐epithelialisation of organ cultured human wounded skin. This result fits with our results of scratch assay using HaCaT KCs, ACA significantly stimulated wound closure in situ. This suggested that ACA had wound healing‐promoting effect in human skin.ConclusionWe found that ACA had wound‐healing promoting effects by stimulating ERK/MAPK and PI3K activation. ACA might be a novel agent for treating chronic wounds.

Epidermal Deletion of HIF-2α Stimulates Wound Closure

Wound closure requires a complex series of micro-environmentally influenced events. A key aspect of wound closure is the migration of keratinocytes across the open wound. It has been found previously that the response to hypoxia via the HIF-1α transcription factor is a key feature of wound closure. The need for hypoxic response is likely due to interrupted wound vasculature as well as infection, and in this work, we investigated the need for a highly related hypoxic response transcription factor, HIF-2α. This factor was deleted tissue-specifically in mice, and the resulting mice were found to have an accelerated rate of wound closure. This is correlated with a reduced bacterial load and inflammatory response in these mice. This indicates that manipulating or reducing the HIF-2α response in keratinocytes could be a useful means to accelerate wound healing and tissue repair.

Wound healing and antibacterial activities of chondroitin sulfate- and acharan sulfate-reduced silver nanoparticles

For topical applications in wound healing, silver nanoparticles (AgNPs) have attracted much attention as antibacterial agents. Herein, we describe a green-synthetic route for the production of biocompatible and crystalline AgNPs using two glycosaminoglycans, chondroitin sulfate (CS) and acharan sulfate (AS), as reducing agents. The synthetic approach avoids the use of toxic chemicals, and the yield of AgNPs formation is found to be 98.1% and 91.1% for the chondroitin sulfate-reduced silver nanoparticles (CS-AgNPs) and the acharan sulfate-reduced silver nanoparticles (AS-AgNPs), respectively. Nanoparticles with mostly spherical and amorphous shapes were observed, with an average diameter of 6.16 ± 2.26 nm for CS-AgNPs and 5.79 ± 3.10 nm for AS-AgNPs. Images of the CS-AgNPs obtained from atomic force microscopy revealed the self-assembled structure of CS was similar to a densely packed woven mat with AgNPs sprinkled on the CS. These nanoparticles were stable under cell culture conditions without any noticeable aggregation. An approximately 128-fold enhancement of the antibacterial activities of the AgNPs was observed against Enterobacter cloacae and Escherichia coli when compared to CS and AS alone. In addition, an in vivo animal model of wound healing activity was tested using mice that were subjected to deep incision wounds. In comparison to the controls, the ointments containing CS-AgNPs and AS-AgNPs stimulated wound closure under histological examination and accelerated the deposition of granulation tissue and collagen in the wound area. The wound healing activity of the ointments containing CS-AgNPs and AS-AgNPs are comparable to that of a commercial formulation of silver sulfadiazine even though the newly prepared ointments contain a lower silver concentration. Therefore, the newly prepared AgNPs demonstrate potential for use as an attractive biocompatible nanocomposite for topical applications in the treatment of wounds.