Step In Wound Healing Research Articles

Hypoxic Preconditioned ADSC Exosomes Enhance Vaginal Wound Healing via Accelerated Keratinocyte Proliferation and Migration Through AKT/HIF‑1α Axis Activation.

Accelerating wound healing is a main consideration in surgery. The three stages of wound healing are inflammatory response, tissue repair and cell proliferation. Much research has focused on epidermal cell proliferation and migration because this is an essential step in wound healing. The current study discovered that exosomes from Adipose-derived stem cell (ADSC) following hypoxic preconditioning (HExo) have a greater promotional effect on vaginal wound healing. Protein kinase B (AKT)/hypoxia-inducible factor 1-alpha (HIF-1α) play an important role in HExo-mediated HaCaT cell migration and proliferation. The promotional effect of HExo on rat wound healing was reversed by both, HIF‑1α and AKT inhibition. Phosphorylation of AKT (p-AKT) or HIF‑1α suppression reversed the protective effect of HExo on vaginal wound healing. Taken together, our study found that hypoxic preconditioning of adipose MSC exosomes enhances vaginal wound healing via accelerated keratinocyte proliferation and migration through AKT/HIF‑1α axis activation.

Electrowriting patterns and electric field harness directional cell migration for skin wound healing

Directional cell migration is a crucial step in wound healing, influenced by electrical and topographic stimulations. However, the underlying mechanism and the combined effects of these two factors on cell migration remain unclear. This study explores cell migration under various combinations of guided straight line (SL) spacing, conductivity, and the relative direction of electric field (EF) and SL. Electrowriting is employed to fabricate conductive (multiwalled carbon nanotube/polycaprolactone (PCL)) and nonconductive (PCL) SL, with narrow (50 μm) and wide (400 μm) spacing that controls the topographic stimulation strength. Results show that various combinations of electrical and topographic stimulation yield significantly distinct effects on cell migration direction and speed; cells migrate fastest with the most directivity in the case of conductive, narrow-spacing SL parallel to EF. A physical model based on intercellular interactions is developed to capture the underlying mechanism of cell migration under SL and EF stimulations, in agreement with experimental observations. In vivo skin wound healing assay further confirmed that the combination of EF (1 V cm−1) and parallelly aligned conductive fibers accelerated the wound healing process. This study presents a promising approach to direct cell migration and enhance wound healing by optimizing synergistic electrical and topographic stimulations.

Matrix Metalloproteinase-9 in the Etiopathogenesis of Placenta Accreta Spectrum: A Literature Review

Abstract The recent increase in placenta accreta spectrum has been correlated with a rise in the rate of cesarean sections. A recent study provides evidence that hampered wound healing results in cesarean scar defects that lead to a failure in the normal process of decidualization and deeper adherence of trophoblasts. Matrix metalloproteinase (MMP) is crucial in every step of wound healing as it alters the wound matrix, facilitating cell migration, as well as tissue remodeling. MMP-9 expression is higher in placental and decidual tissue in cases of placenta accreta. Based on these findings, assessment of MMP-9 expression can shed new light on the etiopathology of placenta accreta spectrum disorder and can be a potential diagnostic marker.

Lonicerin promotes wound healing in diabetic rats by enhancing blood vessel regeneration through Sirt1-mediated autophagy.

Among the numerous complications of diabetes mellitus, diabetic wounds seriously affect patients' quality of life and result in considerable psychological distress. Promoting blood vessel regeneration in wounds is a crucial step in wound healing. Lonicerin (LCR), a bioactive compound found in plants of the Lonicera japonica species and other honeysuckle plants, exhibits anti-inflammatory and antioxidant activities, and it recently has been found to alleviate ulcerative colitis by enhancing autophagy. In this study we investigated the efficacy of LCR in treatment of diabetic wounds and the underlying mechanisms. By comparing the single-cell transcriptomic data from healing and non-healing states in diabetic foot ulcers (DFU) of 5 patients, we found that autophagy and SIRT signaling activation played a crucial role in mitigating inflammation and oxidative stress, and promoting cell survival in wound healing processes. In TBHP-treated human umbilical vein endothelial cells (HUVECs), we showed that LCR alleviated cell apoptosis, and enhanced the cell viability, migration and angiogenesis. Furthermore, we demonstrated that LCR treatment dose-dependently promoted autophagy in TBHP-treated HUVECs by upregulating Sirt1 expression, and exerted its anti-apoptotic effect through the Sirt1-autophagy axis. Knockdown of Sirt1 significantly decreased the level of autophagy, and mitigated the anti-apoptotic effect of LCR. In a STZ-induced diabetic rat model, administration of LCR significantly promoted wound healing, which was significantly attenuated by Sirt1 knockdown. This study highlights the potential of LCR as a therapeutic agent for the treatment of diabetic wounds and provides insights into the molecular mechanisms underlying its effects.

The Role of Stem Cell on Wound Healing After Revascularization-Healing Following Revascularization-Unlocking Skin Potential.

Wound healing is a complex and dynamic process involving a series of cellular and molecular events. Revascularization, the restoration of blood flow to ischemic or damaged tissue, is a key step in wound healing. Adequate vascularization has been recognized as a necessary factor for successful tissue regeneration. In the later stage of revascularization and tissue remodeling in wound healing, stem cells regulate other repair cells and matrix formation by influencing the maturation of blood vessels. The reductive oxidation (REDOX) state may be a key mechanism through stem/progenitor cells to influence endothelial cells to mature blood vessels and improve the quality of healing. Mitochondria may play an important role in this process.

Topical Dihydroartemisinin Improves Wound Healing in Diabetic Mice.

Impaired skin wound healing is a common complication of diabetes mellitus. Angiogenesis is a critical step in wound healing because it allows oxygen and nutrients to reach the injured area, thereby promoting wound cell proliferation, re-epithelialisation, and collagen regeneration. However, the neovascularisation ability of patients with diabetes often decreases. Therefore, finding ways to improve diabetic angiogenesis is important for treating diabetic wounds that do not heal. To the best of our knowledge, it is unclear whether dihydroartemisinin (DHA) affects diabetic wounds. This study sought to determine how topical DHA affects the healing of diabetic wounds and how it is related to markers of angiogenesis. We topically applied DHA to full-thickness cutaneous lesions in a streptozotocin (STZ)-induced diabetic mouse model. Under a fluorescence microscope, the pathological morphology of the wound skin was observed, together with the positive expression of platelet endothelial cell adhesion molecule-1 (CD31) and vascular endothelial growth factor (VEGF). Western blotting was used to determine the CD31 and VEGF protein expression levels. The mRNA expression was determined using qualitative real-time polymerase chain reaction (qRT-PCR). We found that DHA can improve the expression of CD31 and VEGF, and accelerate wound healing in diabetic mice. We believe that DHA promotes angiogenesis, which is associated with increased VEGF signalling in vivo. Therefore, DHA can effectively accelerate the process of diabetic wound healing by promoting angiogenesis, implying that DHA may be used as a topical drug for the treatment of diabetic wounds.

Research advances on the mechanism of extracellular vesicles of adipose-derived mesenchymal stem cells in promoting wound angiogenesis

Wound healing involves complex pathophysiological mechanism, among which angiogenesis is considered as one of the key steps in wound healing, and promoting wound angiogenesis can accelerate wound healing. In recent years, mesenchymal stem cell-derived extracellular vesicles have been proven to produce equivalent effects of wound healing promotion comparable to stem cell therapy, with the advantages of low antigenicity and high biocompatibility. The specific mechanism by which extracellular vesicles facilitate wound healing is still not fully understood and is thought to involve all stages of wound healing. This article focuses on the possible mechanism of extracellular vesicles of adipose-derived mesenchymal stem cells in promoting wound angiogenesis, so as to provide ideas for further study on the mechanism of extracellular vesicles to promote wound healing.

An Effective Peptide-Based Platform for Efficient Exosomal Loading and Cellular Delivery of a microRNA.

Exosomes, membrane-bound nanosized vesicles of biologic origin, are known to contain various molecules, e.g., proteins, lipids, and nucleic acids, which contribute to the exosomes' ability to mediate cell-to-cell communication. Recent impediments of artificial nanoparticles in drug delivery, including low cellular uptake, activation of the immune system, and tissue obstacles, have led scientists to engineer exosomes as drug delivery vehicles. Though exosomes possess inherent properties of stability, biocompatibility, low immunogenicity, and capability to cross biological barriers, there is a need to develop technologies that allow the efficient loading of therapeutic materials into exosomes. Here, we introduced a simple peptide-equipped technology that can enhance the cargo-loading potential of exosomes in a mild loading environment. Specifically, a known cell-penetrating peptide, YARA, derived from human immunodeficiency virus-1 trans-activator of transcription, was covalently conjugated with miR-21-5p, a mammalian microRNA. The conjugate YARA-miR-21-5p was then incubated with exosomes, isolated from either mesenchymal stem cells or cancer cells, for loading. Exosomal loading of YARA-miR-21-5p was time-dependent and demonstrated an impressive 18.6-fold increase in efficiency over exosomal loading of miR-21-5p through incubation. After effective cellular uptake, the loaded exosomes rapidly delivered YARA-miR-21-5p into mammalian cells. Relative to unloaded exosomes and free YARA-miR-21-5p, the loaded exosomes significantly enhanced the proliferation, migration, and invasion of human and mouse fibroblasts, which are vital steps in wound healing. This study lays the groundwork for using cell-penetrating peptides as an innovative approach to efficiently load therapeutic cargos, e.g., microRNAs, into exosomes, which can then be employed to deliver the cargos into cells to yield biological effects.

Platelet-rich plasma counteracts interleukin-1 induced inhibition of collagen biosynthesis through recovery of impaired β1-integrin signaling and prolidase activity in human skin fibroblasts.

Although inflammation is the first step in wound healing, it contributes to down-regulation of collagen biosynthesis delaying the process of tissue regeneration. The study was conducted to evaluate the effects of platelet-rich plasma (PRP) on interleukin-1β (IL-1β) – dependent inhibition of collagen synthesis, prolidase activity, and β1-integrin signaling in cultured human skin fibroblasts. PRP was obtain using the SmartPReP®2 Autologous Platelet Concentrate+ System. Collagen biosynthesis and prolidase activity were measured in confluent human skin fibroblast cultures with IL-1β, PRP, hyaluronic acid (HA), and mixtures of IL-1β with PRP or HA. Immunofluorescence bioimaging analysis was employed to evaluate expression of β1 integrin receptor, cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB) protein. Incubation of fibroblasts with 2% PRP for 24 h contributed to about 500% increase in collagen biosynthesis and a significant increase in the expression of β1-integrin receptor and prolidase activity, compared to the control cells. In the cells treated with IL-1β, collagen biosynthesis, β1-integrin receptor expression, and prolidase activity were decreased while COX-2 and NF-κB expressions were significantly increased. All these processes were recovered to control values by PRP or HA; however, PRP was found to act more effectively than HA. It was found that PRP counteracted IL-1β -dependent inhibition of collagen synthesis through recovery of β1-integrin receptor expression and prolidase activity and down-regulation of COX-2 and NF-κB expressions in cultured fibroblasts. The data suggest that PRP evoke anti-inflammatory activity that is desirable in tissue regeneration.

Wound healing and anti-inflammatory effects of recombinant human angiogenin

New effective wound healing agents are a priority for modern clinical pharmacology. A promising approach would be to develop medicinal products that promote angiogenesis, which is a critical step in wound healing. The aim of the study was to evaluate the wound healing effect of a medicinal product based on recombinant human angiogenin in gel form in various experimental models. Materials and methods: white outbred male rats were used as experimental ani mals. The study compared healing effects of a regenerating product containing recombinant human angiogenin (0.0025%) in gel form and a reference product in full-thickness excision, incision, and burn wound models. The healing effect of the test product in treating chronic wounds was assessed in a model of alloxan-induced diabetes mellitus. The anti-inflammatory effect of the test product containing recombinant human angiogenin was compared with that of another reference product in a model of adjuvant-induced arthritis. Results: according to the study, the test product based on recombinant human angiogenin exerts higher wound healing effect in treating excision, incision, and burn wounds than the reference product (Solcoseryl gel). Being applied, the test product intensifies tissue repair in chronic wounds in the model of alloxan-induced diabetes. The dissociation of necrotic tissues and the progression towards epithelialisation at wound edges are more rapid. The anti-inflammatory effect of the test product based on recombinant human angiogenin is comparable with that of the reference product (Diclofenac gel). Conclusions: the test product based on recombinant human angiogenin in gel form was found to have pronounced wound healing and anti-inflammatory effects comparable with those of reference products.

Effects of Obesity on Infections with Emphasis on Skin Infections and Wound Healing.

Obesity represents a serious health problem as it is rapidly increasing worldwide. Obesity is associated with reduced health span and life span, decreased responses to infections and vaccination and increased frequency of inflammatory conditions. In this review, we summarize published data showing that obesity increases the risk of different types of infections, with a special focus on skin infections. Obesity also induces skin changes and conditions (inflammation-based and hypertrophic) which are often associated with fungi or bacteria overgrowth. The association of obesity with the skin microbiome has been established in both mice and humans. Balance of commensal microbes controls skin homeostasis and the host immune response, while changes in normal physiologic skin microbiome composition and pathologic bacteria contribute to skin diseases. We also summarize the major steps in wound healing and how obesity affects each of them. The role that immune cells have in this process is also described. Although the studies summarized in this review clearly demonstrate the deleterious effects of obesity on wound healing, additional studies are needed to better characterize the cellular and molecular mechanisms involved and identify specific targets of intervention.

Free-cell therapeutics and mechanism of exosomes from adipose-derived stem cells in promoting wound healing: current understanding and future applications.

Free-cell therapeutics and mechanism of exosomes from adipose-derived stem cells in promoting wound healing: current understanding and future applications.

Research advances on mesenchymal stem cell-derived extracellular vesicles in promoting angiogenesis of diabetic ulcers

Extracellular vesicles are nanoparticles secreted by most eukaryotic cells and play important roles in material transport and information transmission between cells, involved in inflammation, angiogenesis, antigen presentation, cell apoptosis, cell differentiation, and other biological processes. The culture supernatant of mesenchymal stem cells is rich in extracellular vesicles, and the extracellular vesicles can regulate the formation of new blood vessels, a key step in wound healing and tissue repair. The persistence of diabetic ulcers is closely related to the blocked formation of wound vascular network. This article reviews the role of extracellular vesicles derived from mesenchymal stem cells in promoting angiogenesis of diabetic ulcers, in order to provide a new idea for the treatment of diabetic ulcers.

Direct Current Electrical Fields Improve Experimental Wound Healing by Activation of Cytokine Secretion and Erk1/2 Pathway Stimulation.

There is growing evidence that cell behaviors can be influenced by the direct current electric fields (EFs). Some behaviors may influence wound healing directly. This study aimed to investigate the effects of EF (200 mV/mm) on immortalized nontumorigenic human epidermal (HaCaT) cells. We established a setup that can transmit an EF and maintain a stable cell culture environment. An EF was applied to HaCaT cells, and scratch-assays were performed as a model of wound healing to observe cell migration. Proliferation was evaluated by mitochondrial activity, total protein, and DNA content. Secretion of healing-associated cytokines was evaluated via cytokine arrays, and Western blot was applied to investigate signaling pathway alterations. Compared with the control group, the migration of cells exposed to EFs significantly increased (p < 0.01). After 7 days, the changes in proliferation also increased significantly (p < 0.05). The cytokine arrays revealed that granulocyte-macrophage colony-stimulating factor (GM-CSF) was the most abundant factor secreted by HaCaT following EF exposure. The signals for phospho-Erk1/2 showed a significant (p < 0.0001) increase following EF exposure. The results demonstrate that exposure of HaCaT cells to EFs has positive effects on migration, proliferation, and cytokine secretion—three important steps in wound healing—and these effects may be partially mediated by activation of the Erk1/2 signaling pathway.

Haemostatic materials for wound healing applications.

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. The first step in wound healing is haemostasis, and the development of haemostatic materials that aid wound healing has accelerated in the past 5 years. Numerous haemostatic materials have been fabricated, composed of different active components (including natural polymers, synthetic polymers, silicon-based materials and metal-containing materials) and in various forms (including sponges, hydrogels, nanofibres and particles). In this Review, we provide an overview of haemostatic materials in wound healing, focusing on their chemical design and operation. We describe the physiological process of haemostasis to elucidate the principles that underpin the design of haemostatic wound dressings. We also highlight the advantages and limitations of the different active components and forms of haemostatic materials. The main challenges and future directions in the development of haemostatic materials for wound healing are proposed.

The plasminogen receptor, Plg-RKT, plays a role in inflammation and fibrinolysis during cutaneous wound healing in mice

Wound healing is a complex physiologic process that proceeds in overlapping, sequential steps. Plasminogen promotes fibrinolysis and potentiates the inflammatory response during wound healing. We have tested the hypothesis that the novel plasminogen receptor, Plg-RKT, regulates key steps in wound healing. Standardized burn wounds were induced in mice and time dependence of wound closure was quantified. Healing in Plg-RKT−/− mice was significantly delayed during the proliferation phase. Expression of inflammatory cytokines was dysregulated in Plg-RKT−/− wound tissue. Consistent with dysregulated cytokine expression, a significant delay in wound healing during the proliferation phase was observed in mice in which Plg-RKT was specifically deleted in myeloid cells. Following wound closure, the epidermal thickness was less in Plg-RKT−/− wound tissue. Paradoxically, deletion of Plg-RKT, specifically in keratinocytes, significantly accelerated the rate of healing during the proliferation phase. Mechanistically, only two genes were upregulated in Plg-RKT−/− compared with Plg-RKT+/+ wound tissue, filaggrin, and caspase 14. Both filaggrin and caspase 14 promote epidermal differentiation and decrease proliferation, consistent with more rapid wound closure and decreased epidermal thickness during the remodeling phase. Fibrin clearance was significantly impaired in Plg-RKT−/− wound tissue. Genetic reduction of fibrinogen levels to 50% completely abrogated the effect of Plg-RKT deletion on the healing of burn wounds. Remarkably, the effects of Plg-RKT deletion on cytokine expression were modulated by reducing fibrinogen levels. In summary, Plg-RKT is a new regulator participating in different phases of cutaneous burn wound healing, which coordinately plays a role in the interrelated responses of inflammation, keratinocyte migration, and fibrinolysis.

Adipose mesenchymal stem cell exosomes promote wound healing through accelerated keratinocyte migration and proliferation by activating the AKT/HIF-1α axis.

Accelerating wound healing is a key consideration for surgeons. The three stages of wound healing include the inflammatory response, cell proliferation and tissue repair, and much research has focused on the migration and proliferation of epidermal cells, since this is one of the most important steps in wound healing. Studies have shown that adipose mesenchymal stem cells (ADSCs) can promote wound healing by releasing exosomes, although the specific mechanism remains unclear. To clarify the role of adipose mesenchymal stem cell exosomes (ADSCs-exo), we constructed a HaCaT cells model and a mouse wound healing model to examine the effects of ADSCs-exo on wound healing. CCK8 assays and the scratch test showed that ADSCs-exo could promote the proliferation and migration of HaCaT cells. Western blotting and real-time PCR showed that ADSCs-exo upregulated the phosphorylation of AKT and the expression of HIF-1α in HaCaT cells. HIF-1α expression was reduced by inhibiting AKT phosphorylation,and the migration of HaCaT cells simultaneously slowed. These results were also confirmed in vivo. In conclusion, we confirmed that ADSCs-exo promote the proliferation and migration of HaCaT cells by regulating the activation of the AKT/HIF-1α signaling pathway, thus promoting wound healing.

Nanomaterials for Angiogenesis in Skin Tissue Engineering.

Damage to skin tissue, which causes the disorder of the patient's body homeostasis, threatens the patient's life and increases the personal and social treatment burden. Angiogenesis, a key step in the wound healing process, provides sufficient oxygen and nutrients to the wound area. However, traditional clinical interventions are not enough to stabilize the formation of the vascular system to support wound healing. Due to the unique properties and multiple functions of nanomaterials, it has made a major breakthrough in the application of medicine. Nanomaterials provide a more effective treatment to hasten the angiogenesis and wound healing, by stimulating fundamental factors in the vascular regeneration phase. In the present review article, the basic stages and molecular mechanisms of angiogenesis are analyzed, and the types, applications, and prospects of nanomaterials used in angiogenesis are detailed. Impact statement Wound healing (especially chronic wounds) is currently a clinically important issue. The long-term nonhealing of chronic wounds often plagues patients, medical systems, and causes huge losses to the social economy. There is currently no effective method of treating chronic wounds in the clinic. Angiogenesis is an important step in wound healing. Nanomaterials had properties that are not found in conventional materials, and they have been extensively studied in angiogenesis. This review article provides readers with the molecular mechanisms of angiogenesis and the types and applications of angiogenic nanomaterials, hoping to bring inspiration to overcome chronic wounds.

Evaluation of Efficacy of Pulsed Electromagnetic Field Therapy as an Adjuvant Therapy in Healing of Diabetic Foot Ulcers

Background and Aim: Foot ulcer is a common complication of diabetes mellitus. The life time risk ofdeveloping foot ulcer is 25 % with an annual incidence of 2-3% and may result in limb amputation if leftuntreated. Diabetic foot ulcers are conventionally treated with wound debridement and off loading. Properwound healing is uncertain in conservative management of these ulcers. Pulsed Electromagnetic Fieldtherapy is a new modality that interacts at various steps in wound healing. This study aims at evaluating theefficacy of pulsed electromagnetic field therapy as an adjunct therapy in diabetic foot ulcers. Method andmaterials: Thirty patients with mean duration of Diabetes 7.8 ±1.47 yrs, mean duration of foot ulcer 4.9±1.2months with Wagner’s grade 1 and 2 were subjected to Pulsed electromagnetic field for 45 min/day for 30days Statistical Analysis: Data was analysed using student paired t -test Results: The patients showed overall66% ±15% reduction in the wound surface area. Less than 50 % reduction is reported in 2 of the patients.About 50-59% reduction is noted in 6 patients, 11 patients showed 60-69% reduction, 7 patients showed 70-79% reduction, 2 patients more than 90% reduction and 2 patients showed 80-89% reduction in the woundarea. None of them reported any side effects. P value of &lt;0.05 was taken to be significant. Discussion andconclusion: Significant reduction in wound surface area observed could be due to Pulsed ElectromagneticField therapy that helped in healing of tissues, improved circulation and reduced inflammation. Thus PEMFcan be an effective and safe adjuvant therapy for treating diabetic foot ulcers.

Toxicity of silver nanoparticles on wound healing: A case study of zebrafish fin regeneration model

Dressings coated with silver nanoparticle (AgNP) are widely used in the management of acute and chronic wounds. However, whether AgNP exerts toxicity on wound healing remains ambiguous. To demonstrate the effects of AgNP on wound healing, we precisely quantified the recovery speed of wound by taking advantage of the fin regeneration of zebrafish. This method also enabled assessment of the adverse effect of AgNP on various steps of wound healing in vivo. We revealed that AgNP treatment at the concentration of 2 μg/ml impaired fin regeneration when exposure was performed at the phases of epithelialization and the beginning of blastema formation. Cell proliferation of regenerative blastema was significantly decreased after AgNP exposure. But the canonical signals including Wingless/Integrated (Wnt), Notch and Fibroblast growth factor (Fgf) which play important roles in cell proliferation during fin regeneration were not modulated at 36 hours post amputation (hpa). Further study showed that AgNP impaired fin regeneration through declining amputation-induced ROS as early as epithelialized phase at 18 hpa, rather than inducing ROS generation. AgNP exposure also promoted recruitment of neutrophils in the early phase of wound healing, which suggests that this event dampened amputation-induced ROS. Overall, this study suggested that application of AgNP-coated dressings should be carefully considered at the beginning stage of wound healing.