Promote Fibroblast Proliferation Research Articles

A novel electrospun polylactic acid silkworm fibroin mesh for abdominal wall hernia repair

ObjectiveAbdominal wall hernias are common abdominal diseases, and effective hernia repair is challenging. In clinical practice, synthetic meshes are widely applied for repairing abdominal wall hernias. However, postoperative complications, such as inflammation and adhesion, are prevalent. Although biological meshes can solve this problem to a certain extent, they face the problems of heterogeneity, rapid degradation rate, ordinary mechanical properties, and high-cost. Here, a novel electrospinning mesh composed of polylactic acid and silk fibroin (PLA-SF) for repairing abdominal wall hernias was manufactured with good physical properties, biocompatibility and low production cost. Materials and methodsFTIR and EDS were used to demonstrate that the PLA-SF mesh was successfully synthesized. The physicochemical properties of PLA-SF were detected by swelling experiments and in vitro degradation experiments. The water contact angle reflected the hydrophilicity, and the stress‒strain curve reflected the mechanical properties. A rat abdominal wall hernia model was established to observe degradation, adhesion, and inflammation in vivo. In vitro cell mesh culture experiments were used to detect cytocompatibility and search for affected biochemical pathways. ResultsThe PLA-SF mesh was successfully synthesized and did not swell or degrade over time in vitro. It had a high hydrophilicity and strength. The PLA-SF mesh significantly reduced abdominal inflammation and inhibited adhesion formation in rat models. The in vitro degradation rate of the PLA-SF mesh was slower than that of tissue remodeling. Coculture experiments suggested that the PLA-SF mesh reduced the expression of inflammatory factors secreted by fibroblasts and promoted fibroblast proliferation through the TGF-β1/Smad pathway. ConclusionThe PLA-SF mesh had excellent physicochemical properties and biocompatibility, promoted hernia repair of the rat abdominal wall, and reduced postoperative inflammation and adhesion. It is a promising mesh and has potential for clinical application.

Therapeutic Potential of Adipose-Derived Stem Cell-Conditioned Medium and Extracellular Vesicles in an In Vitro Radiation-Induced Skin Injury Model.

Radiotherapy (RT) is one of three major treatments for malignant tumors, and one of its most common side effects is skin and soft tissue injury. However, the treatment of these remains challenging. Several studies have shown that mesenchymal stem cell (MSC) treatment enhances skin wound healing. In this study, we extracted human dermal fibroblasts (HDFs) and adipose-derived stem cells (ADSCs) from patients and generated an in vitro radiation-induced skin injury model with HDFs to verify the effect of conditioned medium derived from adipose-derived stem cells (ADSC-CM) and extracellular vesicles derived from adipose-derived stem cells (ADSC-EVs) on the healing of radiation-induced skin injury. The results showed that collagen synthesis was significantly increased in wounds treated with ADSC-CM or ADSC-EVs compared with the control group, which promoted the expression of collagen-related genes and suppressed the expression of inflammation-related genes. These findings indicated that treatment with ADSC-CM or ADSC-EVs suppressed inflammation and promoted extracellular matrix deposition; treatment with ADSC-EVs also promoted fibroblast proliferation. In conclusion, these results demonstrate the effectiveness of ADSC-CM and ADSC-EVs in the healing of radiation-induced skin injury.

РОЛЬ КОЛЛАГЕНА И ГИДРОКСИАПАТИТА В СОСТАВЕ КОМПОЗИЦИОННЫХ КОСТНОПЛАСТИЧЕСКИХ МАТЕРИАЛОВ, ИСПОЛЬЗУЕМЫХ В ЧЕЛЮСТНО-ЛИЦЕВОЙ ХИРУРГИИ (обзор литературы)

Abstract. Introduction. Bone tissue reconstruction is one of the most challenging problems of maxillofacial surgery. This paper provides a review of studies related to the use of hydroxyapatite- and collagen-based osteoplastic materials for jawbone defects. Aim of our study is the review of the latest information on how essential collagen and hydroxyapatite as part of osteoplastic composites used in maxillofacial surgery. Materials and Methods. The published topical studies are reviewed, dealing with the study of collagen and hydroxyapatite as part of osteoplastic composites. Results and Discussion. Collagen implants promote fibroblast proliferation, vascularization of nearby tissues and induce the formation of new bone tissue with its subsequent restructuring. Collagen was also used as a rapidly biodegrading material in form of a gel for the restoration of bone defects. Conclusions. Currently, considering the positive qualities of collagen and hydroxyapatite, we see their widespread use as part of composite bone plastic materials as promising.

The upregulation of circFoxp1 influences keloid by promoting cell proliferation.

As a result of abnormal wound healing in susceptible individuals, keloids are characterized by hyperproliferation of fibroblasts and excessive deposition of the extracellular matrix (ECM). Current surgical and therapeutic modalities provide limited satisfactory results. Circular ribonucleic acids (circRNAs) play a crucial role in the pathogenesis of various fibrotic diseases, but the potential biological function and expression profile of circRNAs in keloid formation remain unknown. In this study, we explored the function of circFoxp1 on keloid formation. Methods: Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) results revealed that circFoxp1 expression was higher in the keloid tissues. Furthermore, RNA-fluorescence in situ hybridization (RNA-FISH) and RNAscope illustrated that circFoxp1 was present in the cytoplasm. Subsequent cellular experiments demonstrated that circFoxp1 overexpression enhanced proliferation, migration, and ECM deposition. In addition, apoptosis was inhibited. Cell proliferation, inflammatory response, and oxidative phosphorylation of fibroblasts were also observed by RNA sequencing and were closely related to scar formation. The therapeutic potential of circFoxp1 was investigated by establishing keloid implantation models. In vivo, circFoxp1 can promote fibroblast proliferation and ECM deposition. RNA pull-down and western blot assays verified the interaction of circFoxp1 with RACK1. The present study reveals that circFoxp1 contributes to the pathological hyperplasia of keloid, which may improve inflammation and cell proliferation. Our data indicate that circFoxp1 may serve as a novel, promising therapeutic target, presenting a new avenue for understanding the underlying pathogenesis of keloid.

Unraveling FOXO3a and USP18 Functions in Idiopathic Pulmonary Fibrosis through Single-Cell RNA Sequencing of Mouse and Human Lungs.

Background Idiopathic pulmonary fibrosis (IPF) is identified as a chronic, progressive lung disease, predominantly marked by enhanced fibroblast proliferation and excessive deposition of extracellular matrix. The intricate interactions between diverse molecular pathways in fibroblasts play a crucial role in driving the pathogenesis of IPF. Methods This research is focused on elucidating the roles of FOXO3a, a transcription factor, and USP18, a ubiquitin-specific protease, in modulating fibroblast functionality in the context of IPF. FOXO3a is well-known for its regulatory effects on cellular responses, including apoptosis and oxidative stress, while USP18 is generally associated with protein deubiquitination. Results Our findings highlight that FOXO3a acts as a critical regulator in controlling fibroblast activation and differentiation, illustrating its vital role in the pathology of IPF. Conversely, USP18 seems to promote fibroblast proliferation and imparts resistance to apoptosis, thereby contributing to the exacerbation of fibrotic processes. The synergistic dysregulation of both FOXO3a and USP18 in fibroblasts was found to significantly contribute to the fibrotic alterations characteristic of IPF. Conclusion Deciphering the complex molecular interactions between FOXO3a and USP18 in fibroblasts provides a deeper understanding of IPF pathogenesis and unveils novel therapeutic avenues, offering a promising potential for not just halting but potentially reversing the progression of this debilitating disease.

Weighted gene co-expression network analysis and machine learning identified the lipid metabolism-related gene LGMN as a novel biomarker for keloid.

The aetiology of keloid formation remains unclear, and existing treatment modalities have not definitively established a successful approach. Therefore, it is necessary to identify reliable and novel keloid biomarkers as potential targets for therapeutic interventions. In this study, we performed differential expression analysis and functional enrichment analysis on the keloid related datasets, and found that multiple metabolism-related pathways were associated with keloid formation. Subsequently, the differentially expressed genes (DEGs) were intersected with the results of weighted gene co-expression network analysis (WGCNA) and the lipid metabolism-related genes (LMGs). Then, three learning machine algorithms (SVM-RFE, LASSO and Random Forest) together identified legumain (LGMN) as the most critical LMGs. LGMN was overexpressed in keloid and had a high diagnostic performance. The protein-protein interaction (PPI) network related to LGMN was constructed by GeneMANIA database. Functional analysis of indicated PPI network was involved in multiple immune response-related biological processes. Furthermore, immune infiltration analysis was conducted using the CIBERSORT method. M2-type macrophages were highly infiltrated in keloid tissues and were found to be significantly and positively correlated with LGMN expression. Gene set variation analysis (GSVA) indicated that LGMN may be related to promoting fibroblast proliferation and inhibiting their apoptosis. Moreover, eight potential drug candidates for keloid treatment were predicted by the DSigDB database. Western blot, qRT-PCR and immunohistochemistry staining results confirmed that LGMN was highly expressed in keloid. Collectively, our findings may identify a new biomarker and therapeutic target for keloid and contribute to the understanding of the potential pathogenesis of keloid.

Selective inhibition of hepatic stellate cell and fibroblast-derived LOXL1 attenuates BDL- and Mdr2-/--induced cholestatic liver fibrosis.

Lysyl oxidase-like 1 (LOXL1) proteins are amine oxidases that play a crucial role in extracellular matrix remodeling due to their collagen cross-linking and intracellular functions. The role of LOXL1 in cholestatic liver fibrosis remains unexplored. We measured LOXL1 expression in two murine models of cholestasis [Mdr2 knockout (Mdr2-/-) and bile duct ligation (BDL)]. We used adeno-associated virus (AAV) serotype 6-mediated hepatic delivery against LOXL1 (AAV2/6-shLoxl1) to investigate the therapeutic efficacy of targeting LOXL1 in cholestatic liver fibrosis. NIH-3T3 murine fibroblasts were used to investigate the function and regulatory mechanisms of LOXL1 in vitro. LOXL1 expression was significantly upregulated in Mdr2-/- and BDL mice compared with their corresponding controls, predominantly in collagen-rich fibrous septa and portal areas. AAV2/6-shLoxl1 significantly reduced LOXL1 levels in Mdr2-/- and BDL mice, mainly in desmin-positive hepatic stellate cells (HSCs) and fibroblasts. Concomitant with reduced LOXL1 expression, there was reduced ductular reaction, inflammation, and fibrosis in both Mdr2-/- and BDL mice. In addition, Loxl1 intervention decreased Ki-67-positive cells in the desmin-positive areas in both Mdr2-/- and BDL mice. Overexpression of LOXL1 significantly promoted fibroblast proliferation by activating the platelet-derived growth factor receptor and extracellular signal-regulated kinase signaling pathways in vitro. Our findings demonstrated that selective inhibition of LOXL1 derived from HSCs/fibroblasts attenuated cholestatic liver/biliary fibrosis, inflammation, ductal reaction, and HSC/fibroblast proliferation. Based on our findings, LOXL1 could be a potential therapeutic target for cholestatic fibrosis.NEW & NOTEWORTHY Selectively, inhibition of HSC/fibroblasts-derived LOXL1 by AAV2/6-shLoxl1 could reduce collagen deposition, HSC/fibroblasts proliferation, and cholestatic liver fibrosis progression. In addition, overexpression of LOXL1 significantly promoted HSC/fibroblast proliferation by activating the PDGFRß/PI3K and ERK signaling pathways in vitro.

Proteomic and single-cell analysis shed new light on the anti-inflammatory role of interferonβ in chronic periodontitis.

Periodontitis, a condition that results in periodontal attachment loss and alveolar bone resorption, contributes to the global burden of oral disease. The underlying mechanism of periodontitis involves the dysbiosis and dyshomeostasis between host and oral microbes, among which the macrophage is one of the major innate immune cell players, producing interferon β (IFNβ) in response to bacterial infection. The objective of this research was to examine the interaction of macrophages with periodontitis and the role and mechanism of IFNβ on macrophages. IFNβ has been shown to have the potential to induce the differentiation of M1 to M2 macrophages, which are stimulated by low levels of lipopolysaccharide (LPS). Additionally, IFNβ has been demonstrated to promote the production of ISG15 by macrophages, which leads to the inhibition of the innate immune response. Moreover, our investigation revealed that IFNβ has the potential to augment the secretion of ISG15 and its downstream cytokine, IL10, in LPS-stimulated macrophages. Single-cell analysis was conducted on the gingival tissues of patients with periodontitis, which revealed a higher proportion of macrophages in the periodontitis-diseased tissue and increased expression of IFNβ, ISG15, and IL10. Gene Set Enrichment Analysis indicated that bacterial infection was associated with upregulation of IFNβ, ISG15, and IL10. Notably, only IL10 has been linked to immunosuppression, indicating that the IFNβ-ISG15-IL10 axis might promote an anti-inflammatory response in periodontitis through IL10 expression. It is also found that macrophage phenotype transitions in periodontitis involve the release of higher levels of IFNβ, ISG15, and IL10 by the anti-inflammatory M2 macrophage phenotype compared to the pro-inflammatory M1 phenotype and myeloid-derived suppressor cells (MDSCs). This implies that the IFNβ-induced production of IL10 might be linked to the M2 macrophage phenotype. Furthermore, cell communication analysis demonstrated that IL10 can promote fibroblast proliferation in periodontal tissues via STAT3 signaling.

Fluoride-activated photothermal system for promoting bacteria-infected wound healing

Although photothermal therapy (PTT) employing nanozymes has shown excellent antibacterial potential, excessive heating generally harms host cells and hinders recovery. Herein, we report an innovative technique for acquiring the programmed temperature by managing the catalytic activity of nanozymes. The photothermal system of CeO2 + F− + TMB can obtain precise photothermal temperature by adjusting the concentration of fluoride ions under near-infrared irradiation. At the optimized photothermal temperature, the photothermal system affords fine photothermal antibacterial treatment with high-efficiency antibacterial effects against Staphylococcus aureus and Escherichia coli in vitro. In vivo wound healing experiments confirm that the system can effectively promote fibroblast proliferation, angiogenesis and collagen deposition with remarkable wound healing efficiency. This strategy offers a novel design concept for creating a new generation of PTT and opens the way for the creation of alternative antibiotics.

Role of passive and active myostimulation for the changing levels of some cytokines

Injury to the anterior cruciate ligament (ACL) of the knee joint is complicated by development of arthrogenic muscle inhibition due to disregulating afferent influences on the excitability of the spinal and supraspinal tracts. The aim of our work was to study electromyography parameters, and myokine levels in the course of myostimulation in traumatic ACL injury.
 28 male athletes with traumatic ACL injuries participated in the study. On admission to the clinic, all patients underwent electromyographic examination of the injured limb by the means of Viking Quest EMG/ EP apparatus (Nicolet, USA). Some patients, 10 days before starting the surgical treatment, underwent passive electrical myostimulation (EMS) of the quadriceps femoris muscle using the INTELECT Advanced device (Chattanooga (DJO), USA). Further on, all patients underwent arthroplasty using a Karl Storz arthroscope (Germany). In the postoperative period, during immobilization for 2-weeks, the patients received EMS. After removing the orthosis, the patients switched to active training. The cytokine levels were studied using ELISA reagent kits from Vector-Best, Novosibirsk (IL-6), or from Cloud-Clone Corp. (China) for TGF1assays. Statistical processing of the material was carried out using the Statistica package. vers.10.0 (StatSoft Inc., USA).
 The highest average amplitude (V) was recorded by electromyography in healthy individuals. In patients of the main group, significantly lower values of the average amplitude were recorded. After a 10-day EMS, a significant increase to the reference values of healthy individuals was noted. In the postsurgical dynamics, EMG indicators without EMS treatment remained at the same low levels. Meanwhile, the values following EMS treatment were comparable with those in healthy individuals, thus reflecting a faster and better muscle recovery after injury. The levels of IL-6 and TGF-1 cytokines (myokines) significantly exceeded the initial levels in the course of EMS. The biological significance of increased IL-6 levels during the muscle exercise may consist the activation of AMP kinase and/or phosphatidylinositol-3-kinase at the level of skeletal muscles thus providing more efficient supply of energy substrate to the muscles. TGF-1 promotes fibroblast proliferation, thus increasing collagen content.
 Passive and active EMS leads to an improvement in electromyography parameters, along with increased concentration of myokines (IL-6 and TGF-1) in peripheral blood, thus promoting improvement of energy balance, increasing the anti-inflammatory and repair potential of the damaged tissues.

PLA-HPG based coating enhanced anti-biofilm and wound healing of Shikonin in MRSA-infected burn wound.

Burn wounds are susceptible to bacterial infections, including Methicillin-resistant Staphylococcus aureus (MRSA), which typically form biofilms and exhibit drug resistance. They also have specific feature of abundant exudate, necessitating frequent drug administration. Shikonin (SKN) has been reported to reverse MRSA drug resistance and possesses anti-biofilm and wound healing properties, however, it suffers from drawbacks of low solubility and instability. In this study, we developed PLA-HPG based bioadhesive nanoparticles SKN/BNP, which demonstrated a drug loading capacity of about 3.6%, and exhibited sustained-release behavior of SKN. The aldehyde groups present on the surface of BNP improved the local adhesion of SKN/BNP both in vitro and in vivo, thereby reducing the frequency of drug dosing in exudate-rich burn wounds. BNP alone enhanced proliferation and migration of the fibroblast, while SKN/BNP promoted fibroblast proliferation and migration as well as angiogenesis. Due to its bioadhesive property, BNP directly interacted with biofilm and enhanced the efficacy of SKN against MRSA biofilm in vitro. In a mouse model of MRSA-infected burn wounds, SKN/BNP demonstrated improved anti-biofilm and wound healing efficiency. Overall, our findings suggest that SKN/BNP holds great promise as a novel and effective treatment option for clinical applications in MRSA-infected burn wounds.

The mechanisms related to fibroblasts in burn surface.

Mesenchymal stem cells (MSCs) can promote burn wound healing, skin appearance, and function recovery by promoting the differentiation and migration of fibroblasts of a wound. The burn environment can activate the autophagy of MSCs. However, it is not clear whether this autophagy can affect the proliferation and migration of fibroblasts. In this study, pretreated MSCs with rapamycin and 3-methyladenine modulated autophagy and co-cultured with fibroblasts of burn. Cell migration was detected by immunofluorescence chemical staining. Western blot analysis and enzyme-linked immunosorbent assay were performed to detect 2,3-Dioxygenase (IDO), cytokine synthesis inhibitory factor 10 (IL-10), cytokine synthesis inhibitory factor 6 (IL-6), prostaglandin E2 (PGE2), transforming growth factor beta 1 (TGF-β1) proteins levels, and the autophagy proteins p62 and microtubule-associated protein LC3-II/I. We demonstrated that autophagy regulates MSCs survival and proliferation in burn wound transplants and found that autophagy inhibition with 3-methyladenine reduced MSCs-mediated, fibroblast proliferation and migration in burn environment. However, rapamycin-induced autophagy had the opposite effect and increased the TGF-β1 expression. Therefore, we speculate that MSCs may promote fibroblast proliferation and migration by secreting TGF-β1 via the AKT/mTOR (RAC-alpha serine/threonine-protein kinase/mammalian target of rapamycin) pathway. Autophagy of MSCs regulates burn wound fibroblast proliferation and migration by affecting TGF-β1 and prostaglandin E2 production adjacent to MSCs transplanted on the burn wound. The results of this study provide a potential strategy for promoting MSCs treatment of burns.

Lysozyme promotes renal fibrosis through the JAK/STAT3 signal pathway in diabetic nephropathy.

Diabetic nephropathy (DN) is a leading cause of kidney failure. Lysozyme (LYZ) is an essential component of innate immunity and exhibits antibacterial properties. However, LYZ has been reported to induce nephropathy, implying a possible association between impaired renal function and lysozyme expression. Bioinformatics analysis was used to predict the hub gene associated with DN, and the differential expression of the hub gene was confirmed using a mouse model. A mouse model of streptozotocin (STZ)-induced diabetic nephropathy was established to investigate the correlation between DN and LYZ expression, and the functionality of LYZ was verified through knockdown and overexpression experiments conducted in vivo. Immunohistochemistry (IHC) was utilized to assess fibrosis-related markers and cytokines, while Masson staining was performed to assess renal fibrosis. Fibroblast proliferation was assessed using the Cell Counting Kit-8 (CCK-8) assay. The role of the JAK pathway was confirmed using the JAK inhibitor AG490, and Western blot was used to investigate the underlying mechanisms. Mechanistically, 25 mM glucose promotes the expression of LYZ in fibroblastic cells, and LYZ may in turn promote the proliferation of renal interstitial fibroblasts. Western blot shows that glucose can activate STAT3 in an LYZ-dependent manner, and the JAK inhibitor AG490 can partially suppress LYZ-induced STAT3 activation. Furthermore, in vivo observations have revealed that overexpression of LYZ is associated with the senescent phenotype of renal tubular epithelial cells (RTECs). Lysozyme promotes kidney fibrosis via the JAK/STAT3 signaling pathway in diabetic nephropathy, and glucose may promote fibroblast proliferation by promoting LYZ auto-secretion.

Plasma-generated nitric oxide radical (NO•) promotes the proliferation of fibroblast cells in liquid

The promotion of cell proliferation by non-equilibrium atmospheric-pressure plasma is a promising technology for regenerative medicine. The fibroblast suspension was irradiated with electrically neutral radicals. Radial irradiation was performed using an atmospheric-pressure radical generator with a working gas mixture of Ar, O2, and N2. Carboxy-PTIO (c-PTIO), a scavenger of nitric oxide radical (NO•), was dissolved in the fibroblast suspension. Selective irradiation with electrically neutral radicals promoted fibroblast proliferation by 36% without c-PTIO in liquid. In contrast, proliferation-promoting effects were significantly reduced to 13% with c-PTIO. Fluorescence probes for reactive oxygen and nitrogen species (RONS) and NO• showed that intracellular RONS and NO• levels were increased by radical irradiation and reduced with c-PTIO in the fibroblast suspension. NO• was detected in the radical-irradiated solutions using ERS. These results suggested that plasma-generated NO• promotes fibroblast proliferation in liquids.

Dual gene-activated dermal scaffolds regulate angiogenesis and wound healing by mediating the coexpression of VEGF and angiopoietin-1.

The vascularization of dermal substitutes is a key challenge in efforts to heal deep skin defects. In this study, dual gene-activated dermal scaffolds (DGADSs-1) were fabricated by loading nanocomposite particles of polyethylenimine (PEI)/multiple plasmid DNAs (pDNAs) encoding vascular endothelial growth factor and angiopoietin-1 at a ratio of 1:1. In a similar manner, DGADSs-2 were loaded with a chimeric plasmid encoding both VEGF and Ang-1. In vitro studies showed that both types of DGADSs released PEI/pDNA nanoparticles in a sustained manner; they demonstrated effective transfection ability, leading to upregulated expression of VEGF and Ang-1. Furthermore, both types of DGADSs promoted fibroblast proliferation and blood vessel formation, although DGADSs-1 showed a more obvious promotion effect. A rat full-thickness skin defect model showed that split-thickness skin transplanted using a one-step method could achieve full survival at the 12th day after surgery in both DGADSs-1 and DGADSs-2 groups, and the vascularization time of dermal substitutes was significantly shortened. Compared with the other three groups of scaffolds, the DGADSs-1 group had significantly greater cell infiltration, collagen deposition, neovascularization, and vascular maturation, all of which promoted wound healing. Thus, compared with single-gene-activated dermal scaffolds, DGADSs show greater potential for enhancing angiogenesis. DGADSs with different loading modes also exhibited differences in terms of angiogenesis; the effect of loading two genes (DGADSs-1) was better than the effect of loading a chimeric gene (DGADSs-2). In summary, DGADSs, which continuously upregulate VEGF and Ang-1 expression, offer a new functional tissue-engineered dermal substitute with the ability to activate vascularization.

Recent Advances in Stimuli-Responsive Hydrogel-Based Wound Dressing.

Polymeric materials have found increasing use in biomedical applications in the last decades. Among them, hydrogels represent the chosen class of materials to use in this field, in particular as wound dressings. They are generally non-toxic, biocompatible, and biodegradable, and they can absorb large amounts of exudates. Moreover, hydrogels actively contribute to skin repair promoting fibroblast proliferation and keratinocyte migration, allowing oxygen to permeate, and protecting wounds from microbial invasion. As wound dressing, stimuli-responsive systems are particularly advantageous since they can be active only in response to specific environmental stimuli (such as pH, light, ROS concentration, temperature, and glucose level). In this review, we briefly resume the human skin's structure and functions, as well as the wound healing phases; then, we present recent advances in stimuli-responsive hydrogels-based wound dressings. Lastly, we provide a bibliometric analysis of knowledge produced in the field.

Tunicate-mimetic antibacterial hydrogel based on metal ion crosslinking and chitosan functionalization for wound healing

With the increasing prevalence of drug-resistant bacterial infections and frequent occurrences of slow wound healing, the development of novel antibacterial wound dressings has become a serious challenge. Hydrogel dressings have attracted extensive attention on wound healing due to their unique three-dimensional network structures and properties. However, it is a challenge to develop natural long-acting antibacterial hydrogels with multiple functions such as excellent cell affinity, wet adhesion and mechanical properties. Inspired by the wound healing mechanism and adhesion characteristics of tunicates, a series of biomimetic antibacterial hydrogels were prepared by utilizing pyrogallol-modified chitosan (GACS) and polyvinyl alcohol (PVA) as matrix, zinc ions (Zn2+) as crosslinking and antibacterial agents, and ethyl N-lauroyl l-arginate hydrochloride (LAE) as the antibacterial active ingredient. The morphology, swelling, water retention, degradability, wet adhesion, biocompatibility, mechanical and rheological properties of PVA/GACS/Zn2+/LAE hydrogels were evaluated. And the adhesion ability conferred by the pyrogallol structures enabled the hydrogel with enhanced antibacterial effect and hemostatic ability. Moreover, the in vivo experiments on rat models with full-thickness infected wounds confirmed that PVA/GACS/Zn2+/LAE hydrogels could efficiently kill bacteria, significantly improve the wound microenvironment, greatly promote fibroblast proliferation and collagen deposition and ultimately accelerate wound healing. In a word, this study provided a feasible and simple way for the development of biomimetic antibacterial hydrogel dressings applied in infected wounds, which could not only seal wounds with various shapes and provide a moist and antibacterial environment for wounds, but also have certain mechanical strength, excellent wound adhesion, good biocompatibility and hemostatic performance.

Ultrathin, flexible, and piezoelectric Janus nanofibrous dressing for wound healing

The healing process of infected skin lesions is often delayed by many factors including bacterial infection, excessive accumulation of wound exudate, poor local perfusion, and low cell recruitment. Development of wound dressing for efficient wound management and promotion of wound healing is a great challenge. Herein, we constructed a Janus nanofiber dressing with the comprehensive capacities of bacterial killing, piezoelectrical stimulation for promoting fibroblast migration, and wound exudate removal via unidirectional liquid delivery. The rationally designed Janus nanofibrous dressing with ultrathin, flexible, breathable, and piezoelectric characteristics is fabricated via the facile layer-by-layer electrostatic spinning technology. The hydrophilic layer of the dressing is composed of randomly arranged polycaprolactone/gelatin (PCL/Gel) nanofibers, while the hydrophobic layer consists of well-aligned Ag nanoparticles (Ag NPs)-doped piezoelectric polyvinylidene fluoride (PVDF/Ag) nanofibers. The in vitro and in vivo experimental results demonstrate that the Janus dressing can not only drain excess wound exudate out of the wound unidirectionally and kill local bacteria, but also generate dynamic piezopotential under normal body motions to promote fibroblast proliferation and migration, collagen deposition, angiogenesis, and re-epithelialization, which accelerates rapid wound healing on mice. The smart Janus dressing will provide a new approach for acceleration of wound healing and wound management.

Exosomal IRF1-loaded rat adipose-derived stem cell sheet contributes to wound healing in the diabetic foot ulcers

BackgroundCell-based therapy has been recognized as a novel technique for the management of diabetic foot ulcers, and cell-sheet engineering leads to improved efficacy in cell transplantation. This study aims to explore the possible molecular mechanism of the rat adipose-derived stem cell (ASC) sheet loaded with exosomal interferon regulatory factor 1 (IRF1) in foot wound healing.MethodsRats were rendered diabetic with streptozotocin, followed by measurement of miR-16-5p expression in wound tissues. Relationship between IRF1, microRNA (miR)-16-5p, and trans-acting transcription factor 5 (SP5) was analyzed using luciferase activity, RNA pull-down, and chromatin immunoprecipitation assays. IRF1 was overexpressed in rat ASCs (rASCs) or loaded onto the rASC sheet, and then exosomes were extracted from rASCs. Accordingly, we assessed the effects of IRF1-exosome or IRF1-rASC sheet on the proliferation and migration of the fibroblasts along with endothelial cell angiogenesis.ResultsmiR-16-5p was poorly expressed in the wound tissues of diabetic rats. Overexpression of miR-16-5p promoted fibroblast proliferation and migration as well as endothelial cell angiogenesis, thus expediting wound healing. IRF1 was an upstream transcription factor that could bind to the miR-16-5p promoter and increase its expression. In addition, SP5 was a downstream target gene of miR-16-5p. IRF1-exosome from rASCs or the IRF1-rASC sheet facilitated the foot wound healing in diabetic rats through miR-16-5p-dependent inhibition of SP5.ConclusionThe present study demonstrates that exosomal IRF1-loaded rASC sheet regulates miR-16-5p/SP5 axis to facilitate wound healing in diabetic rats, which aids in development of stem cell-based therapeutic strategies for diabetic foot wounds.

Fabrication of Cell-Laden AME-Loaded Collagen-Based Hydrogel Promotes Fibroblast Proliferation and Wound Healing In Vitro.

The biological factors secreted from cells and cell-based products stimulate growth, proliferation, and migration of the cells in their microenvironment, and play vital roles in promoting wound healing. The amniotic membrane extract (AME), which is rich in growth factors (GFs), can be loaded into a cell-laden hydrogel and released to a wound site to promote the healing of the wound. The present study was conducted to optimize the concentration of the loaded AME that induces secretion of GFs and structural collagen protein from cell-laden AME-loaded collagen-based hydrogels, to promote wound healing in vitro. In this experimental study, fibroblast-laden collagen-based hydrogel loaded with different concentrations of AME (0.1, 0.5, 1, and 1.5 mg/mL, as test groups) and without AME (as control group), were incubated for 7 days. The total proteins secreted by the cells from the cell-laden hydrogel loaded with different concentrations of AME were collected and the levels of GFs and type I collagen were assessed using ELISA method. Cell proliferation and scratch assay were done to evaluate the function of the construct. The results of ELISA showed that the concentrations of GFs in the conditioned medium (CM) secreted from the cell-laden AME-loaded hydrogel were significantly higher than those secreted by only the fibroblast group. Interestingly, the metabolic activity of fibroblasts and the ability of the cells to migrate in scratch assay significantly increased in the CM3-treated fibroblast culture compared to other groups. The concentrations of the cells and the AME for preparation of CM3 group were 106 cell/mL and 1 mg/mL, respectively. We showed that 1 mg/ml of AME loaded in fibroblast-laden collagen hydrogel significantly enhanced the secretion of EGF, KGF, VEGF, HGF, and type I collagen. The CM3 secreted from the cell-laden AME-loaded hydrogel promoted proliferation and scratch area reduction in vitro.