Search Results (12)

Background: Diabetic foot ulcers (DFUs) are difficult to heal because hyperglycemia-associated pathological exudation, excessive oxidative stress, chronic inflammation, and impaired cellular regeneration jointly maintain a nonhealing wound microenvironment. This study aimed to develop and evaluate a composite hydrogel containing Periplaneta americana (PA) extract and calamine as a Zn²⁺ source for dynamic modulation of the diabetic wound microenvironment and promotion of tissue repair. Methods: A PA composite hydrogel was prepared and assessed in vitro for reactive oxygen species (ROS)-scavenging activity and effects on fibroblast migration. Therapeutic efficacy was further evaluated in a streptozotocin (STZ)-induced diabetic full-thickness wound model in rats. Wound closure, histological remodeling, oxidative stress markers, inflammatory mediators, growth factors, angiogenesis, and AGEs-RAGE/NF-κB pathway-related changes were analyzed. Results: The composite hydrogel reduced excessive intracellular ROS and enhanced fibroblast migration in vitro compared with pathological-condition controls. In diabetic rats, topical treatment accelerated macroscopic wound closure and promoted more mature histological repair. Mechanistic analyses showed attenuation of the AGEs-RAGE/NF-κB signaling axis, accompanied by restoration of superoxide dismutase activity, reduction of malondialdehyde levels, and suppression of TNF-α-associated inflammatory responses. The improved wound microenvironment was associated with increased expression of platelet-derived growth factor and basic fibroblast growth factor, enhanced cellular proliferation, and increased neovascularization within the wound tissue. Conclusions: The PA composite hydrogel improved diabetic wound healing by concurrently alleviating oxidative and inflammatory barriers and enhancing regenerative signaling. These findings suggest that microenvironment-modulating PA composite hydrogel systems may represent a promising therapeutic strategy for refractory diabetic wounds. Full article

Skin wound healing is a complex and highly coordinated biological process involving inflammation, cell migration and proliferation, angiogenesis, extracellular matrix remodeling and tissue regeneration. While the zebrafish-derived antimicrobial peptide AP10W exhibits broad-spectrum antimicrobial properties, its potential in tissue repair remains unexplored. Herein, we demonstrate that AP10W possesses intrinsic wound-healing capabilities, providing a preliminary investigation into its underlying mechanisms. In this study, using a full-thickness murine wound model and in vitro cell-based assays to evaluate the effects of AP10W on fibroblasts, keratinocytes, endothelial cells, and macrophages, we found that AP10W significantly promoted fibroblast and keratinocyte migration and proliferation. Furthermore, it enhanced endothelial cell motility, survival, and tube formation, while upregulating key pro-angiogenic factors, including Vascular endothelial growth factor A (VEGFA), Platelet-derived growth factor (PDGF), and Fibroblast growth factor 2 (FGF2). Concurrently, AP10W drove macrophage reprogramming from a pro-inflammatory M1 phenotype toward a pro-healing M2 state, as evidenced by upregulated Arginase-1 (Arg-1) and Interleukin-10 (Il-10) expression, alongside attenuated Tumor necrosis factor-alpha (Tnf-α), Interleukin-1 beta (Il-1β), Interleukin-6 (Il-6), and Inducible nitric oxide synthase (iNOS) levels. In vivo, the topical application of AP10W accelerated wound closure, markedly improving re-epithelialization, collagen deposition, vascularization, tissue perfusion, and skin appendage regeneration. Preliminary mechanistic studies revealed that AP10W increased YAP expression and nuclear translocation; conversely, the pharmacological inhibition of YAP significantly abrogated these pro-healing effects. Collectively, our findings identify AP10W as a multifunctional peptide with potent wound-healing properties, positioning it as a promising candidate for wound therapy. Full article

Context: Hair loss (alopecia) presents both aesthetic and psychological challenges, significantly impacting quality of life. Platelet-rich plasma (PRP) therapy has gained prominence due to its ability to deliver growth factors and modulate local inflammation. However, uncertainties remain regarding the mechanisms through which systemic inflammation, oxidative stress, and coagulation factors influence PRP’s efficacy. Objectives: This narrative review explores the impact of inflammatory biomarkers (e.g., NLR, PLR, IL-6, TNF-α) and growth factors (VEGF, TGF-β, FGF) on hair regeneration in PRP therapy. It discusses how oxidative stress and vitamin status (B12, D, folate) correlate with therapeutic success. Additionally, it examines the PRP preparation protocols and combined approaches (microneedling, minoxidil, LLLT) that may amplify clinical responses. Results: The synthesized data highlight that elevated systemic inflammation (increased NLR/PLR values) can limit PRP’s effectiveness, while the regulation of inflammation and optimization of antioxidant status can enhance hair density and thickness. Integrating vitamins and an anti-inflammatory diet into the therapeutic protocol is associated with more stable hair growth and reduced adverse reactions. The variability in PRP’s preparation and activation methods remains a major obstacle, underscoring the need for standardization. Conclusions: Integrating inflammatory biomarkers with oxidative stress indicators provides fresh insights for tailoring PRP therapies in alopecia. Multimodal treatment strategies combined with collaborative multicenter studies—in which biological markers are embedded within rigorous protocols—could establish standardized methodologies and significantly enhance the treatment success. Full article

The heat treatment process of Ti-6Al-4V alloy alters its microstructural features such as prior-β grain size, Widmanstatten α lath thickness, Widmanstatten α volume fraction, grain boundary α lath thickness, total α volume fraction, α colony size, and α platelet length. These microstructural features affect the material’s mechanical properties (UTS, YS, and %EL). The relationship between microstructural features and mechanical properties is very complex and non-linear. To understand these relationships, we developed an artificial neural network (ANN) model using experimental datasets. The microstructural features are used as input parameters to feed the model and the mechanical properties (UTS, YS, and %EL) are the output parameters. The influence of microstructural parameters was investigated by the index of relative importance (IRI). The mean edge length, colony scale factor, α lath thickness, and volume fraction affect UTS more. The model-predicted results show that the UTS of Ti-6Al-4V decreases with the increase in prior β grain size, Widmanstatten α lath thickness, grain boundaries α thickness, colony scale factor, and UTS increases with mean edge length. Full article

Some scholars have suggested that the clinical application of exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs-exo) might represent a novel strategy to improve diabetic wound healing. However, the mechanisms underlying the effects of hucMSCs-exo on wound healing remain poorly understood. This study aimed to identify the mechanism of hucMSCs-exo in treating diabetic wounds. HucMSCs-exo were isolated from human umbilical cord mesenchymal stem cells (hucMSCs) and subcutaneously injected into full-thickness wounds in diabetic rats. Wound healing closure rates and histological analysis were performed. The levels of tumor necrosis factor-α (TNF-α), macrophage mannose receptor (MMR/CD206), platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), and vascular endothelial growth factor (VEGF) were detected by immunohistochemistry. The degree of collagen deposition was examined using Masson’s trichrome staining. Gross evaluation of wound healing was carried out from day 0 to 14 post-surgery, and the wound site was harvested for histology on days 3, 7, and 14 post-wounding. HucMSCs-exo transplantation increased diabetic wound healing. In vitro, hucMSCs-exo promoted the proliferation of human umbilical vein endothelial cells (HUVECs) and NIH-3T3 cells. In vivo, hucMSCs-exo reduced wound area and inflammatory infiltration and increased collagen fibers. In addition, wound tissues in the hucMSCs-exo group had higher CD206, CD31, and VEGF expressions and lower TNF-α levels than those in the control group on day 14. Our results demonstrated that hucMSCs-exo facilitated diabetic wound repair by inducing anti-inflammatory macrophages and promoting angiogenesis and collagen deposition. Full article

The present study was focused on the relationship between an α platelet microstructure and the properties of TC21 alloy, and the tensile deformation process was revealed by in situ observation. To obtain the α platelet microstructures, the samples were administered a solution treatment (1000 °C for 15 min) and then cooled to room temperature by different cooling methods (furnace cooling (FC), open-door furnace cooling (OFC), air cooling (AC), and water quench (WQ), corresponding to an increased cooling rate). It is found that α platelets become thinner and colonies become narrower with the increase in cooling rate. The formation of the platelet microstructure is based on the preferred Burgers orientation relationship of {110}_β//{0001}_α and <111>_β//<11$\overline{2}$0>_α. The α platelets orientation changes with the cooling rate. These differences in α platelets thickness and orientation result in the excellent ductility of the sample with thick platelets and the high strength of the samples with thin platelets. During the in situ tensile deformation process, the crack propagation path is deflected in the presence of grain boundaries, α platelets, and α colonies with different orientations. The fracture of the sample with thick α platelets shows better ductility compared to those with thin α platelets. Full article

The electron beam powder bed fusion (EB-PBF) process is typically carried out using a layer thickness between 50 and 100 μm with the accelerating voltage of 60 kV for the electron beam. This configuration ensures forming accuracy but limits building efficiency. The augmentation of the accelerating voltage enlarges the molten pool due to the rise in penetrability, suggesting that a higher layer thickness can be used. Therefore, the effects of layer thickness and accelerating voltage were investigated simultaneously in this study to explore the feasibility of efficiency improvement. Ti6Al4V was fabricated by EB-PBF using layer thicknesses of 200 and 300 μm. Two accelerating voltage values of 60 and 90 kV were used to study their effects under expanded layer thickness. The results reveal that dense parts with the ultimate tensile strength higher than 950 MPa and elongation higher than 9.5% could be fabricated even if the layer thickness reached 300 μm, resulting in a building rate of up to 30 mm³/s. The expansion of the layer thickness could decrease the minimum bulk energy density needed to fabricate dense parts and increase the α platelet thickness, which improved the energy efficiency. However, expanding layer thickness had a significant negative effect on surface roughness, but it could be improved by applying augmented accelerating voltage. Full article

Aluminum containing M_n+1AX_n (MAX) phase materials have attracted increasing attention due to their corrosion resistance, a pronounced self-healing effect and promising diffusion barrier properties for hydrogen. We synthesized Ti₂AlN coatings on ferritic steel substrates by physical vapor deposition of alternating Ti- and AlN-layers followed by thermal annealing. The microstructure developed a {0001}-texture with platelet-like shaped grains. To investigate the oxidation behavior, the samples were exposed to a temperature of 700 °C in a muffle furnace. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) depth profiles revealed the formation of oxide scales, which consisted mainly of dense and stable α-Al₂O₃. The oxide layer thickness increased with a time dependency of ~t^1/4. Electron probe micro analysis (EPMA) scans revealed a diffusion of Al from the coating into the substrate. Steel membranes with as-deposited Ti₂AlN and partially oxidized Ti₂AlN coatings were used for permeation tests. The permeation of deuterium from the gas phase was measured in an ultra-high vacuum (UHV) permeation cell by mass spectrometry at temperatures of 30–400 °C. We obtained a permeation reduction factor (PRF) of 45 for a pure Ti₂AlN coating and a PRF of ~3700 for the oxidized sample. Thus, protective coatings, which prevent hydrogen-induced corrosion, can be achieved by the proper design of Ti₂AlN coatings with suitable oxide scale thicknesses. Full article

The performance of two selective electron beam melting operation modes, namely the manual mode and the automatic ‘build theme mode’, have been investigated for the case of a Ti-6Al-4V alloy (45–105 μm average particle size of the powder) in terms of porosity, microstructure, and mechanical properties. The two operation modes produced notable differences in terms of build quality (porosity), microstructure, and properties over the sample thickness. The number and the average size of the pores were measured using a light microscope over the entire build height. A density measurement provided a quantitative index of the global porosity throughout the builds. The selective-electron-beam-melted microstructure was mainly composed of a columnar prior β-grain structure, delineated by α-phase boundaries, oriented along the build direction. A nearly equilibrium α + β mixture structure, formed from the original β-phase, arranged inside the prior β-grains as an α-colony or α-basket weave pattern, whereas the β-phase enveloped α-lamellae. The microstructure was finer with increasing distance from the build plate regardless of the selected build mode. Optical measurements of the α-plate width showed that it varied as the distance from the build plate varied. This microstructure parameter was correlated at the sample core with the mechanical properties measured by means of a macro-instrumented indentation test, thereby confirming Hall-Petch law behavior for strength at a local scale for the various process conditions. The tensile properties, while attesting to the mechanical performance of the builds over a macro scale, also validated the indentation property measurement at the core of the samples. Thus, a direct correlation between the process parameters, microstructure, porosity, and mechanical properties was established at the micro and macro scales. The macro-instrumented indentation test has emerged as a reliable, easy, quick, and yet non-destructive alternate means to the tensile test to measure tensile-like properties of selective-electron-beam-melted specimens. Furthermore, the macro-instrumented indentation test can be used effectively in additive manufacturing for a rapid setting up of the process, that is, by controlling the microscopic scale properties of the samples, or to quantitatively determine a product quality index of the final builds, by taking advantage of its intrinsic relationship with the tensile properties. Full article

In this paper, thick-section TC4 alloy was welded to itself by laser-MIG hybrid (LAMIG) welding. The microstructure of the welded joints was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results revealed that α’ and β phases were formed in the weld seam. The effects of heat input (E) on the microstructure and tensile strength of the joints were investigated. With the increase of heat input, the residence time of platelet α’ martensite in the high-temperature phase changing zone became longer and the thickness of platelet α’ martensite increased. Furthermore, the β thickness became large, and tangling dislocations were found to exist in platelet α’. In addition, the increasing heat input could cause a decrease in the tensile strength. The failed dimple pattern experienced a change from equiaxed to tearing, which was harmful to the property of the joint. Full article

In vitro cell culture methods are used extensively to study cellular migration, proliferation, and differentiation, which play major roles in wound healing but the results often do not translate to the in vivo environment. One alternative would be to establish an ex vivo model utilizing human discarded skin to evaluate therapies in a more natural setting. The purpose of this study was to institute such a model by creating ‘wounds’ in the center of a piece of discarded skin and treating them with three different biomaterials: collagen, polyethylene glycol (PEG)-fibrin, or PEG-platelet free plasma (PFP). Explants were cultured for 14 days with supernatant and microscopy images collected every 3 days to assess cytotoxicity and epithelialization. After 14 days, the explants were fixed, sectioned, and stained for cytokeratin-10 (CK-10), alpha-smooth muscle actin (α-SMA), and wheat germ (WG). Compared to controls, similar levels of cytotoxicity were detected for 12 days which decreased slightly at day 14. The PEG-PFP hydrogel-treated wounds epithelialized faster than other treatments at days 6 to 14. A 6-8 cell layer thick CK-10+ stratified epidermis had developed over the PEG-PFP hydrogel and cells co-stained by WG and α-SMA were observed within the hydrogel. An ex vivo model was established that can be used practically to screen different therapies exploring wound healing. Full article

Background: The present study investigated the effectiveness of platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) in wound healing suppressed by corticosteroid in rats. Methods: Forty rats were separated into four groups. To disrupt the wound-healing processes, intraperitoneal single dose 10 mg/kg methylprednisolone was administered to all rats with the exception of Sham-S group. Then, full-thickness incision was performed to the abdominal skin of all animals, and PRP or MSCs were applied to the incision line except the Sham-S and Sham-M group animals. Ten days later, all animals were sacrificed to investigate: tissue collagenization, inflammation, and re-epithelialization grades histopathologically; and tissue hydroxyproline (HP), interleukin-1β (IL-1β), tumor necrosis factor-α levels biochemically. Results: Collagenization (p = 0.003) and inflammation grade (p = 0.002) values were higher in PR group. Tissue HP level value was found to be high in MC group (p < 0.001). Tissue IL-1β level value of Sham-M group was lower than those of other groups (p < 0.001). Conclusions: This preliminary study revealed that PRP could improve the histopathological grades in wound healing which was suppressed by corticosteroid in rats, while MSCs could show their therapeutic effects via biochemical route. These positive effects were more salient in PR group. Full article