IGF-1-Expressing Placenta-Derived Mesenchymal Stem Cells Promote Scalding Wound Healing

IGF-1 inhibits inflammation and accelerates angiogenesis via Ras/PI3K/IKK/NF-κB signaling pathways to promote wound healing

Exogenous insulin-like growth factor-1 (IGF-1) has been reported to promote wound healing through regulation of vascular endothelial cells (VECs). Despite the existing studies of IGF-1 on VEC and its role in angiogenesis, the mechanisms regarding anti-inflammatory and angiogenetic effects of IGF-1 remain unclear. In this study, we investigated the wound-healing process and the related signaling pathway of IGF-1 using an inflammation model induced by IFN-γ. The results demonstrated that IGF-1 can increase cell proliferation, suppress inflammation in VECs, and promote angiogenesis. In vivo studies further confirmed that IGF-1 can reduce inflammation, enhance vascular regeneration, and improve re-epithelialization and collagen deposition in acute wounds. Importantly, the Ras/PI3K/IKK/NF-κB signaling pathways was identified as the mechanisms through which IGF-1 exerts its anti-inflammatory and pro-angiogenic effects. These findings contribute to the understanding of IGF-1's role in wound healing and may have implications for the development of new wound treatment approaches.

Bacterial cellulose as an ideal potential treatment for burn wounds: A comprehensive review

Burn wound regeneration is a complex process, which has many serious challenges such as slow wound healing, secondary infection, and inflammation. Therefore, it is essential to utilise appropriate biomaterials to accelerate and guide the wound healing process. Bacterial cellulose (BC), a natural polymer synthesised by some bacteria, has attracted much attention for wound healing applications due to its unique properties including excellent physicochemical and mechanical properties, simple purification process, three-dimensional (3D) network structure similar to extracellular matrix, high purity, high water holding capacity and significant permeability to gas and liquid. BC's lack of antibacterial activity significantly limits its biomedical and tissue engineering application, but adding antimicrobial agents to it remarkably improves its performance in tissue regeneration applications. Burn wound healing is a complex long-lasting process. Using biomaterials in wound treatment has shown that they can satisfactorily accelerate wound healing. The purpose of this review is to elaborate on the importance of BC-based structures as one of the most widely used modern wound dressings in the treatment of burn wounds. In addition, the combination of various drugs, agents, cells and biomolecules with BC to expand its application in burn injury regeneration is discussed. Finally, the main challenges and future development direction of BC-based structures for burn wound repair are considered. The four most popular search engines PubMed/MEDLINE, Science Direct, Scopus and Google Scholar were used to help us find relevant papers. The most frequently used keywords were bacterial cellulose, BC-based biocomposite, wound healing, burn wound and vascular graft.

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Heparinized Acellular Hydrogels for Magnetically Induced Wound Healing Applications

The control of angiogenesis has the potential to be used for regulation of several pathological and physiological processes, which can be instrumental on the development of anticancer and wound healing therapeutical approaches. In this study, mesenchymal stem/stromal cells (MSCs) were seeded on magnetic-responsive gelatin, with or without heparin functionalization, and exposed to a static 0.08 T magnetic field (MF), for controlling their anti-inflammatory and angiogenic activity, with the aim of accelerating tissue healing. For the first time, it was examined how the amount of heparin and magnetic nanoparticles (MNPs) distributed on gelatin scaffolds affected the mechanical properties of the hydrogels and the morphology, proliferation, and secretome profiling of MSCs. The findings demonstrated that the addition of MNPs and heparin affects the hydrogel swelling capacity and renders distinct MSC proliferation rates. Additionally, MF acts as a topographical cue to guide MSCs alignment and increases the level of expression of specific genes and proteins that promote angiogenesis. The results also suggested that the presence of higher amounts of heparin (10 μg/cm3) interferes with the secretion and limits the capacity of angiogenic factors to diffuse through the hydrogel and into the culture medium. Ultimately, this study shows that acellular heparinized hydrogels efficiently retain the angiogenic growth factors released by magnetically stimulated MSCs thus rendering superior wound contraction (55.8% ± 0.4%) and cell migration rate (49.4% ± 0.4%), in comparison to nonheparinized hydrogels (35.2% ± 0.7% and 37.8% ± 0.7%, respectively). Therefore, these heparinized magnetic hydrogels can be used to facilitate angiogenesis in various forms of tissue damage including bone defects, skin wounds, and cardiovascular diseases, leading to enhanced tissue regeneration.

Human Placenta-Derived Mesenchymal Stem Cells Combined With Artificial Dermal Scaffold Enhance Wound Healing in a Tendon-Exposed Wound of a Rabbit Model

To overcome the difficulty of vascular regeneration in exposed tendon wounds, we combined human placenta-derived mesenchymal stem cells (hPMSCs) with an artificial dermal scaffold and assessed their role in promoting vascular regeneration and wound healing in vivo. hPMSCs were isolated from the human placenta and characterized based on their morphology, phenotypic profiles, and pluripotency. New Zealand rabbits were used to establish an exposed tendon wound model, and hPMSCs and artificial dermal scaffolds were transplanted into the wounds. The results of gross wound observations and pathological sections showed that hPMSCs combined with artificial dermal scaffold transplantation increased the vascularization area of the wound, promoted wound healing, and increased the survival rate of autologous skin transplantation. Following artificial dermal scaffold transplantation, hPMSCs accelerated the vascularization of the dermal scaffold, and the number of fibroblasts, collagen fibers, and neovascularization in the dermal scaffold after 1 week were much higher than those in the control group. Immunohistochemical staining further confirmed that the expression of the vascular endothelial cell marker, CD31, was significantly higher in the combined transplantation group than in the dermal scaffold transplantation group. Our findings demonstrated that hPMSCs seeded onto artificial dermal scaffold could facilitate vascularization of the dermal scaffold and improve tendon-exposed wound healing.

Versatile Hydrogel Dressings That Dynamically Regulate the Healing of Infected Deep Burn Wounds

Severe burns threaten patient lives due to pain, inflammation, bacterial infection, and scarring. Most burn dressings that are commonly used perform a single function and are not well suited for the management of deep burns. Therefore, a multifunctional antimicrobial peptide- and stem cell-loaded macroporous hydrogel that can fight bacterial infection and regulate wound healing progression by temporally regulating cytokine production by internal stem cells is developed. The macroporous skeletal hydrogel is manufactured via the cryogenic gelation of hyaluronic acid (cryogel). Based on the oxidative polymerization reaction of dopamine, the antimicrobial peptide DP7 is immobilized on the surface of the cryogel (DA7CG). Placental mesenchymal stem cells (PMSCs) are then packaged inside the macroporous hydrogel (DA7CG@C). According to the results of in vitro and in vivo experiments, during the inflammatory phase, DP7 inhibits infection and modulates inflammation; during the proliferative phase, DA7CG@C accelerates the regeneration of skin, blood vessels, and hair follicles via internal stem cells; and during the remodeling phase, DA7CG@C contributes to extracellular matrix remodeling due to the ability of DP7 to regulate the paracrine secretion of PMSCs, synergistically promoting scar-free healing. DA7CG@C can participate in all phases of wound healing; therefore, it is a promising dressing for burn treatment.

Mesenchymal stem cells paracrine proteins from three-dimensional dynamic culture system promoted wound healing in third-degree burn models

Recovery of skin function remains a significant clinical challenge for deep burns owing to the severe scar formation and poor appendage regeneration, and stem cell therapy has shown great potential for injured tissue regeneration. Here, a cell-free therapy system for deep burn skin was explored using mesenchymal stem cell paracrine proteins (MSC-PP) and polyethylene glycol (PEG) temperature-sensitive hydrogels. A three-dimensional (3D) dynamic culture system for MSCs' large-scale expansion was established using a porous gelatin microcarrier crosslinked with hyaluronic acid (PGM-HA), and the purified MSC-PP from culture supernatant was characterized by mass spectrometric analysis. The results showed the 3D dynamic culture system regulated MSCs cell cycle, reduced apoptosis, and decreased lactic acid content, and the MSC-PP produced in 3D group can promote cell proliferation, migration, and adhesion. The MSC-PP + PEG system maintained stable release in 28 days of observation in vitro. The in vivo therapeutic efficacy was investigated in the rabbit's third-degree burn model, and saline, PEG, MSC-PP, and MSC-PP + PEG treatments groups were set. The in vivo results showed that the MSC-PP + PEG group significantly improved wound healing, inhibited scar formation, and facilitated skin appendage regeneration. In conclusion, the MSC-PP + PEG sustained-release system provides a potentially effective treatment for deep burn skin healing.

Secretome from myoblasts statically loaded at low intensity promotes tenocyte proliferation via the IGF-1 receptor pathway

Exercise is widely recognized as beneficial for tendon healing. Recently, it has been described that muscle-derived molecules secreted in response to static exercise influence tendon healing. In this study, the optimal static loading intensity for tendon healing and the composition of secretome released by myoblasts in response to different intensities of static strain were investigated. In an in vitro coculture model, myoblasts were mechanically loaded using a Flexcell Tension System. Tenocytes were seeded on transwell inserts that allowed communication between the tenocytes and myoblasts without direct contact. Proliferation and migration assays, together with RNA sequencing, were used to determine potential cellular signaling pathways. The secretome from myoblasts exposed to 2% static loading increased the proliferation and migration of the cocultured tenocytes. RNA-seq analysis revealed that this loading condition upregulated the expression of numerous genes encoding secretory proteins, including insulin-like growth factor-1 (IGF-1). Confirmation of IGF-1 expression and secretion was carried out using qPCR and enzyme-linked immunosorbt assay (ELISA), revealing a statistically significant upregulation in response to 2% static loading in comparison to both control conditions and higher loading intensities of 5% and 10%. Addition of an inhibitor of the IGF-1 receptor (PQ401) to the tenocytes significantly reduced myoblast secretome-induced tenocyte proliferation. In conclusion, IGF-1 may be an important molecule in the statically loaded myoblast secretome, which is responsible for influencing tenocytes during exercise-induced healing.

Combined negative effects of microplastics and plasticizer DEHP: The increased release of Nets delays wound healing in mice

Environmental harmful pollutants microplastics (MPs) and di (2-ethyl) hexyl phthalate (DEHP) are widely residual in the environment, which may cause lesion to multiple apparatus by inducing oxidative stress, threatening the health of human and animals. Neutrophil extracellular traps (Nets) are involved in skin wound healing. Most studies focused on the individual effects of different poisons on animals and ecosystems, but there are few studies on the accumulation and interaction of multiple poisons. The purpose of this study is to explore the effect of DEHP and MPs co-exposure on skin wound healing and the formation of Nets. For this purpose, we detected this hypothesis by replicating the DEHP and MPs-exposed skin wound model in mice, as well as the co-culture system of neutrophil and fibroblast. The results displayed that MPs and DEHP exposure delayed skin healing, which was more pronounced in the combined exposure group. In vitro and in vivo experiments confirmed that compared with the DEHP or MPs group, the DEHP+MPs group had more significant oxidative stress, increased Nets release and inflammatory factors, and inhibited the Wnt/β-catenin pathway and fibrosis-related factors. N-acetylcysteine (NAC) attenuated these phenomena. Through the co-culture system, we confirmed that the overproduction of Nets induced fibroblasts to exacerbate inflammatory responses and inhibit Wnt pathway and fibrosis. Overall, DEHP and MPs can produce synergistic toxic injury in mice skin wounds, and the excessive activation of ROS/Nets can aggravate inflammatory and inhibit fibrosis, resulting in delayed wound healing.

Mesenchymal Stem Cells in Burn Wound Management

Mesenchymal stem cells have a known regenerative potential and are used in many indications. They secrete many growth factors, including for fibroblasts (FGF), endothelium (VEGF), as well as 14 anti-inflammatory cytokines, and they stimulate tissue regeneration, promoting the secretion of proteins and glycosaminoglycans of extracellular matrices, such as collagen I, II, III, and V, elastin, and also metalloproteinases. They secrete exosomes that contain proteins, nucleic acids, lipids, and enzymes. In addition, they show the activity of inactivating free radicals. The aim of this study was an attempt to collect the existing literature on the use of stem cells in the treatment of a burn wound. There were 81 studies included in the analysis. The studies differed in terms of the design, burn wound model, source of stem cells, and methods of cellular therapy application. No major side effects were reported, and cellular therapy reduced the healing time of the burn wound. Few case reports on human models did not report any serious adverse events. However, due to the heterogeneity of the evidence, cellular therapy in burn wound treatment remains an experimental method.

Mesenchymal Stem Cell Mechanisms of Action and Clinical Effects in Osteoarthritis: A Narrative Review

With the insufficient satisfaction rates and high cost of operative treatment for osteoarthritis (OA), alternatives have been sought. Furthermore, the inability of current medications to arrest disease progression has led to rapidly growing clinical research relating to mesenchymal stem cells (MSCs). The availability and function of MSCs vary according to tissue source. The three primary sources include the placenta, bone marrow, and adipose tissue, all of which offer excellent safety profiles. The primary mechanisms of action are trophic and immunomodulatory effects, which prevent the further degradation of joints. However, the function and degree to which benefits are observed vary significantly based on the exosomes secreted by MSCs. Paracrine and autocrine mechanisms prevent cell apoptosis and tissue fibrosis, initiate angiogenesis, and stimulate mitosis via growth factors. MSCs have even been shown to exhibit antimicrobial effects. Clinical results incorporating clinical scores and objective radiological imaging have been promising, but a lack of standardization in isolating MSCs prevents their incorporation in current guidelines.

Preparation, Characterization, and Biological Evaluation of Transparent Thin Carboxymethyl-Chitosan/Oxidized Carboxymethyl Cellulose Films as New Wound Dressings

Full thickness burns in which the damage penetrates deep into the skin layers and reaches underneath the muscle, compel the need for more effective cure. Herein, cross-linked carboxymethyl-chitosan (CM-chitosan) films, prepared by Schiff base association with oxidized carboxymethyl cellulose (OCMC), are investigated regarding the wound healing capacity on full thickness burn injuries in vivo. Transparent thin CM-chitosan/OCMC films are obtained with tensile strength reaching 6.11 MPa, elongation at break above 27%, and water absorption more than 800%, which operates in favor of absorbing excess exudate and monitoring the wound status. Furthermore, the nonadherent CM-chitosan/OCMC films, with satisfactory biodegradability, cell, and tissue compatibility, are readily used to the wound sites and easily removed following therapy on scalded tissue so as to alleviate the suffering from burn. The films efficiently promote epithelial and dermal regeneration compared to the control, achieving 75.9% and 94.4% wound closure, respectively, after 14 and 27 days. More importantly, CM-chitosan/OCMC films accelerate wound healing with natural mechanisms which include controlling inflammatory response, reducing apoptosis, promoting fibroblast cell proliferation, and collagen formation. In conclusion, the CM-chitosan/OCMC films elevate the repair ratio of burn injuries and have great potential for facilitating the healing process on full-thickness exuding wounds.