Accelerated Wound Closure Research Articles

Curative effect and mechanisms of Radix Arnebiae oilon burn wound healing in rats.

Radix Arnebiae oil (RAO) is a clinically useful traditional Chinese medical formula with outstanding curative effects on burns. However, the mechanism of the effect of RAO on wound healing remains unclear. The present study investigated the molecular mechanisms of the potential curative effect of RAO on wound healing. The concentrations of the main constituents shikonin, imperatorin and ferulic acid in RAO detected by HPLC were 24.57, 3.15 and 0.13 mg/mL, respectively. A rat burn model was established, and macroscopic and histopathological studies were performed. RAO significantly accelerated wound closure and repair scarring, increased superoxide dismutase activities, and reduced malondialdehyde. RAO also downregulated interleukin (IL)-6, IL-1β and tumor necrosis factor-α in wound tissues, and increased secretion of vascular endothelial growth factor, epidermal growth factor and transforming growth factor (TGF)-β1. RAO increased the gene expression of TGF-β1, type Ⅰ and Ⅲ collagen, and increased the protein expression of TGF-β1, phosphorylation of PI3K and Akt. In conclusion, RAO likely promoted wound healing via antioxidant and anti-inflammatory activities, and increased re-epithelization. Activation of the TGF-β1/PI3K/Akt pathway may play an important role in the healing efficacy of RAO. These findings suggested that RAO could be a promising alternative local treatment for burn wound healing.

In situ forming ROS-scavenging hybrid hydrogel loaded with polydopamine-modified fullerene nanocomposites for promoting skin wound healing

BackgroundExcessive oxidative stress at the wound sites always leads to a prolonged healing and even causes chronic inflammatory wounds. Therefore, antioxidative dressings with multiple features are desired to improve wound healing performance. Herein, we fabricated a ROS-scavenging hybrid hydrogel by incorporating mussel-inspired fullerene nanocomposites (C60@PDA) into gelatin methacryloyl (GelMA) hydrogel.ResultsThe developed C60@PDA/GelMA hydrogel showed a sustainable free radical scavenging ability, and eliminated ROS to protect cells against external oxidative stress damage. Besides, the hydrogel presented favorable cytocompatibility, hemocompatibility, and antibacterial ability in vitro. Furthermore, in a mouse full-thickness wound defect model, the in situ forming hybrid hydrogel accelerated wound closure by 38.5% and 42.9% on day 3 and day 7 over the control. Histological results demonstrated that hybrid hydrogels effectively enhanced wound healing on re-epithelialization, collagen deposition and angiogenesis.ConclusionCollectively, the C60@PDA/GelMA hydrogel could be a promising dressing for promoting cutaneous wound repair.

A bilayer mupirocin/bupivacaine-loaded wound dressing based on chitosan/poly (vinyl alcohol) nanofibrous mat: Preparation, characterization, and controlled drug release

An infected skin wound caused by external injury remains a serious challenge. Electrospun drug-loaded nanofibers with antibacterial properties based on biopolymers have been widely explored for wound healing. In this study, the double-layer CS/PVA/mupirocin (CPM) + CS/PVA/bupivacaine (CPB) mats were prepared by electrospinning method (20 % polymer weight) and then crosslinked with glutaraldehyde (GA) to optimize the water-resistant and biodegradation properties for wound dressing applications. The morphology of mats was characterized as defect-free and interconnected nanofibers by Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Fourier Transform Infrared Spectrometry (FTIR) analysis also assessed the chemical structural properties. The porosity, surface wettability, and swelling degree of the dual-drug loaded mats were improved by about 20 %, 12°, and 200 % of the CS/PVA sample to provide a moist environment for efficient wound breathing and repairing. This highly porous mat facilitated the wound exudates absorption and air permeability excellently, reducing the chance of bacterial infections by inhibiting the growth of S. aureus bacterial colonies with a zone of 71.3 mm diameter. In vitro drug release results showed a high-burst release of 80 % and a continuous release profile for bupivacaine and mupirocin, respectively. MTT assay and in vivo tests indicated >90 % of cell viability and improvement in cell proliferation. It triply accelerated wound closure compared to the control group, reaching nearly full closure after 21 days as a potential clinical wound treatment.

Salvianolic-Acid-B-Loaded HA Self-Healing Hydrogel Promotes Diabetic Wound Healing through Promotion of Anti-Inflammation and Angiogenesis.

Inflammatory dysfunction and angiogenesis inhibition are two main factors leading to the delayed healing of diabetic wounds. Hydrogels with anti-inflammatory and angiogenesis-promoting effects have been considered as promising wound care materials. Herein, a salvianolic acid B (SAB)-loaded hyaluronic acid (HA) self-healing hydrogel (HA/SAB) with anti-inflammatory and pro-angiogenesis capacities for diabetic wound healing is reported. The HA hydrogel was prepared via the covalent cross-linking of aldehyde groups in oxidized HA (OHA) and hydrazide groups in adipic dihydrazide (ADH)-modified HA (HA-ADH) with the formation of reversible acylhydrazone bonds. The obtained HA hydrogel exhibited multiple favorable properties such as porous structures, excellent self-healing properties, a sustainable release capacity of SAB, as well as excellent cytocompatibility. In addition, the effects of the SAB-loaded HA self-healing hydrogel were investigated via a full-thickness skin defect model using diabetic rats. The HA/SAB hydrogel showed enhanced skin regeneration effects with accelerated wound closure, shorter remaining dermal space length, thicker granulation tissue formation, and more collagen deposition. Furthermore, reduced inflammatory response and enhanced vascularization were found with HA/SAB2.5 hydrogel-treated wounds, indicating that the hydrogel promotes diabetic wound healing through the promotion of anti-inflammation and angiogenesis. Our results suggest that the fabricated SAB-loaded HA self-healing hydrogel is promising as a wound dressing for the treatment of diabetic wounds.

TIBIAL CORTEX TRANSVERSE TRANSPORT ACCELERATES WOUND HEALING VIA ENHANCED ANGIOGENESIS AND IMMUNOMODULATION

Treatment for delayed wound healing resulting from peripheral vascular diseases and diabetic foot ulcers remain a challenge. A novel surgical technique named Tibial Cortex Transverse Transport has been developed for treating peripheral ischaemia, with encouraging clinical effects. However, its underlying mechanisms remain unclear. In present study, we aimed to explore the wound healing effects after undergoing this novel technique via multiple ways.A novel rat model of Tibial Cortex Transverse Transport was established with a designed external fixator and effects on wound healing were investigated. All rats were randomized into 3 groups, with 12 rats per group: sham group (negative control), fixator group (positive control) and Tibial Cortex Transverse Transport group. Laser speckle perfusion imaging, vessel perfusion, histology and immunohistochemistry were used to evaluate the wound healing processes.Gross and histological examinations showed that Tibial Cortex Transverse Transport technique accelerated wound closure and enhanced the quality of the newly formed skin tissues. In Tibial Cortex Transverse Transport group, HE staining demonstrated a better epidermis and dermis recovery, while immune-histochemical staining showed that Tibial Cortex Transverse Transport technique promoted local collagen deposition. Tibial Cortex Transverse Transport technique also benefited to angiogenesis and immunomodulation. In Tibial Cortex Transverse Transport group, blood flow in the wound area was higher than that ofother groups according to laser speckle imaging with more blood vessels observed. Enhanced neovascularization was seen in the Tibial Cortex Transverse Transport group with double immune-labelling of CD31 and α-SMA. The M2 macrophages at the wound site in the Tibial Cortex Transverse Transport group was also increased.Tibial cortex transverse transport technique accelerated wound healing through enhanced angiogenesis and immunomodulation.

Abstract 104: The role of APOBEC3A in ovarian cancer progression

Abstract Cancer progression is enabled by the accumulation of somatic mutations and genomic aberrations, leading to metastasis, treatment resistance, and poor clinical outcomes. The analysis of cancer genomes has identified APOBEC3A (A3A) cytidine deaminase activity as a cause of somatic mutagenesis in over 20 tumor types. In particular, A3A mutational signatures are found in a large proportion of ovarian tumors, ranging from 2-26% depending on subtype. Furthermore, genomic analyses of ovarian tumors suggest that A3A mutagenesis occurred during early metastatic progression, indicating the potential for A3A activity to promote clonal evolution. In non-ovarian tumors, A3A activity is associated with metastatic progression through the identification of A3A mutational patterns enriched in or unique to metastatic sites. Therefore, we hypothesized that aberrant A3A activity on OC genomes would increase mutagenesis, promote clonal diversity, and enable tumor progression. To examine the impact of aberrant A3A activity during OC progression, we developed a model system of inducible A3A expression in OC cell lines. We treated cells for 45 days with doxycycline to induce A3A expression (long-term, LT-A3A) and generated three biological replicates by treating individual wells of the parental lines independently. A3A is known to mutate the genome stochastically. Despite this, all versions of LT-A3A cells exhibited similar phenotypes compared to non-treated isogenic controls (NT). LT-A3A cells demonstrated increased colony formation relative to NT cells, indicating improved cell survival. We assessed cellular migration by scratch-wound assays and found that LT-A3A cells exhibited accelerated wound closure rates compared to NT controls, despite similar proliferation rates. In addition, cellular invasion was assessed by spheroid Matrigel invasion assays in which the invasive distance was significantly greater in LT-A3A cells relative to NT controls. By generating cell lines with a catalytically inactive doxycycline-inducible A3A transgene, we determined that the observed A3A-mediated cellular phenotypes were deaminase-dependent. To assess the molecular alterations driving these phenotypic differences, we performed RNA-seq on LT-A3A and NT cell lines. Gene set enrichment analysis of differentially expressed genes identified significant overlap between the Epithelial-Mesenchymal Transition (EMT) and WNT/Beta Catenin, Hedgehog, and TGFβ signaling gene sets. These related signaling pathways converge on the promotion of metastasis and cancer progression. These data suggest that aberrant A3A activity promotes the survival, migration, and invasion of OC cells by altering intracellular signaling pathways that promote EMT. Our ongoing experimental investigation will assess how long-term A3A mutagenesis impacts genomic heterogeneity and how A3A affects tumor behavior in animal models. Citation Format: Jessica Merritt Devenport, Mary Mullen, Katherine Fuh, Abby Green. The role of APOBEC3A in ovarian cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 104.

Engineered BMSCs-Derived Exosomal miR-542-3p Promotes Cutaneous Wound Healing.

The healing of cutaneous wounds requires better strategies, which remain a challenge. Previous reports indicated that the therapeutic function of mesenchymal stem cells is mediated by exosomes. This work demonstrated the regenerative effects of engineered BMSCsderived Exosomal miR-542-3p in skin wound mouse models. Bone marrow mesenchymal stem cells (BMSCs) -derived exosomes (BMSCs-Exos) were isolated by ultracentrifugation and identified by Transmission Electron Microscope (TEM) and Nanoparticle Tracking Analysis (NTA). BMSCs-Exo was loaded with miRNA-542-3p by electroporation. We explored the effects of miRNA-542-3p-Exo on the proliferation and migration of Human Skin Fibroblasts (HSFs)/Human dermal microvascular endothelial cells (HMECs). In addition, The angiogenesis of HMECs was detected by Tube formation assay in vitro. The effects of miRNA-542-3p-Exo in the skin wound mouse model were detected by H&E staining, Masson staining, and immunofluorescence analysis. We assessed the effect of miRNA-542-3p-Exo on collagen deposition, new blood vessel formation, and wound remodeling in a skin wound mouse model. MiRNA-542-3p-Exos could be internalized by HSFs/HMECs and enhance the proliferation, migration, and angiogenesis of HSFs/HMECs in vitro and in vivo. The protein expression of collagen1/3 was significantly increased after miRNA-542-3p-Exo treatment in HSFs. In addition, the local injection of miRNA-542-3p-Exo promoted cellular proliferation, collagen deposition, neovascularization, and accelerated wound closure. This study suggested that miRNA-542-3p-Exo can stimulate HSFs/HMECs function. The treatment of miRNA-542-3p-Exo in the skin wound mouse model significantly promotes wound repair. The therapeutic potential of miRNA-542-3p-Exo may be a future therapeutic strategy for cutaneous wound healing.

The Antimicrobial Peptide Esculentin-1a(1-21)NH2 Stimulates Wound Healing by Promoting Angiogenesis through the PI3K/AKT Pathway.

Delayed wound healing is a persistent medical problem mainly caused by decreased angiogenesis. Esculentin-1a(1-21)NH2 [Esc-1a(1-21)NH2], has broad-spectrum antibacterial properties which comes from frog skins. It has shown promise as a treatment for wound healing. However, its effects on angiogenesis as well as the mechanism by which esc-1a(1-21)NH2 enhanced wound healing remained unclear. In this study, we analyzed the structural properties and biocompatibility of esc-1a(1-21)NH2 and evaluated its effect on wound closure using a full-thickness excision model in mice. Our results showed that esc-1a(1-21)NH2 significantly accelerated wound healing by increasing collagen deposition and angiogenesis, characterized by elevated expression levels of platelet, endothelial cell adhesion molecule-1 (CD31) and proliferating cell nuclear antigen (PCNA). Furthermore, the angiogenic activity of esc-1a(1-21)NH2 was confirmed in vitro by various assays. Esc-1a(1-21)NH2 significantly promoted cell migration and cell proliferation in human umbilical vein vascular endothelial cells (HUVECs) via activation of the phosphatidylinositol 3'-kinase (PI3K)/protein kinase B (AKT) pathway, and upregulated the expression of CD31 at both mRNA and protein levels. The effect of esc-1a(1-21)NH2 on angiogenesis was diminished by LY294002, a PI3K pathway inhibitor. Taken together, this study demonstrates that esc-1a(1-21)NH2 accelerates wound closure in mice by promoting angiogenesis via the PI3K/AKT signaling pathway, suggesting its effective application in the treatment of wound healing.

Mitoxantrone targets both host and bacteria to overcome vancomycin resistance in Enterococcus faecalis.

Antibiotic resistance critically limits treatment options for infection caused by opportunistic pathogens such as enterococci. Here, we investigate the antibiotic and immunological activity of the anticancer agent mitoxantrone (MTX) in vitro and in vivo against vancomycin-resistant Enterococcus faecalis (VRE). We show that, in vitro, MTX is a potent antibiotic against Gram-positive bacteria through induction of reactive oxygen species and DNA damage. MTX also synergizes with vancomycin against VRE, rendering the resistant strains more permeable to MTX. In a murine wound infection model, single-dose MTX treatment effectively reduces VRE numbers, with further reduction when combined with vancomycin. Multiple MTX treatments accelerate wound closure. MTX also promotes macrophage recruitment and proinflammatory cytokine induction at the wound site and augments intracellular bacterial killing in macrophages by up-regulating the expression of lysosomal enzymes. These results show that MTX represents a promising bacterium- and host-targeted therapeutic for overcoming vancomycin resistance.

Bioresorbable, wireless, and battery-free system for electrotherapy and impedance sensing at wound sites.

Chronic wounds, particularly those associated with diabetes mellitus, represent a growing threat to public health, with additional notable economic impacts. Inflammation associated with these wounds leads to abnormalities in endogenous electrical signals that impede the migration of keratinocytes needed to support the healing process. This observation motivates the treatment of chronic wounds with electrical stimulation therapy, but practical engineering challenges, difficulties in removing stimulation hardware from the wound site, and absence of means to monitor the healing process create barriers to widespread clinical use. Here, we demonstrate a miniaturized wireless, battery-free bioresorbable electrotherapy system that overcomes these challenges. Studies based on a splinted diabetic mouse wound model confirm the efficacy for accelerated wound closure by guiding epithelial migration, modulating inflammation, and promoting vasculogenesis. Changes in the impedance provide means for tracking the healing process. The results demonstrate a simple and effective platform for wound site electrotherapy.

Tumor tissue derived extracellular vesicles promote diabetic wound healing

The diabetic wound nowadays remains a major public health challenge, which is characterized by overproduced reactive oxygen species (ROS). However, the current therapy for diabetic wounds is limited for reliable data in the general application. The growth of tumors has been revealed to share parallels with wound healing. Extracellular vesicles (EVs) derived from breast cancer have been reported to promote cell proliferation, migration and angiogenesis. The tumor tissue-derived EVs (tTi-EVs) of breast cancer performance a feature inheritance from original tissue and might accelerate the diabetic wound healing. We wonder whether the tumor-derived EVs are able to accelerate diabetic wound healing. In this study, tTi-EVs were extracted from breast cancer tissue via ultracentrifugation and size exclusion. Subsequently, tTi-EVs reversed the H2O2-induced inhibition of fibroblast proliferation and migration. Moreover, tTi-EVs significantly accelerated wound closure, collagen deposition and neovascularization, and finally promoted wound healing in diabetic mice. The tTi-EVs also reduced the level of oxidative stress in vitro and in vivo. Besides, the biosafety of tTi-EVs were preliminarily confirmed by blood tests and morphological analysis of major organs. Collectively, the present study proves that tTi-EVs can suppress oxidative stress and facilitate diabetic wound healing, which puts forward a novel function of tTi-EVs and provides potential treatment for diabetic wounds.

Phosphorus magnesium fiber regulates macrophage polarization through TRPM7 to accelerate wound healing

Wound healing is a complex process that can be delayed by persistent inflammatory responses after trauma. Many studies have found that in situ application of biomaterials releases metal ions into wounds to promote wound healing, but the underlying mechanism has not been elucidated. Therefore, we developed a novel nanoscale functional material, phosphorus magnesium fiber (PMF), as a wound dressing to explore its association with wound healing. In this study, in vivo wound healing results showed that PMF accelerated wound closure in full-thickness wound animal models, accompanied by collagen deposition and granulation formation. Moreover, PMF accelerated macrophage polarization by regulating TRPM7-ERK1/2 signaling through the long-term release of magnesium ions into the wound, which contributes to enhancing cell proliferation, growth factor production, and synthesis of ECM in the wound bed, ultimately facilitating wound healing. In vitro studies revealed that PMF promoted the polarization of macrophages to the anti-inflammatory M2 phenotype. Meanwhile, PMF up-regulated TRPM7-ERK1/2 expression. In conclusion, our study confirmed the relationship between PMF and macrophage behavior mediated by the TRPM7 channel protein and subsequently investigated the function of PMF in wound healing. This magnesium-based nanofiber material offers an innovative method for treating open wounds and is anticipated to be used as a wound dressing in the field of tissue regeneration.

Bacterial cellulose-based hydrogel with antibacterial activity and vascularization for wound healing

Skin wounds need an appropriate wound dressing to help prevent bacterial infection and accelerate wound closure. Bacterial cellulose (BC) with a three-dimensional (3D) network structure is an important commercial dressing. However, how to effectively load antibacterial agents and balance the antibacterial activity is a lingering issue. Herein, this study aims to develop a functional BC hydrogel containing silver-loaded zeolitic imidazolate framework-8 (ZIF-8) antibacterial agent. The tensile strength of the prepared biopolymer dressing is >1 MPa, the swelling property is over 3000 %, the temperature can reach 50 °C in 5 min with near-infrared (NIR) and the release of Ag+ and Zn2+ is stable. In vitro investigation shows that the hydrogel displays enhanced antibacterial activity, and the bacteria survival ratios are only 0.85 % and 0.39 % against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In vitro cell experiments present that BC/polydopamine/ZIF-8/Ag (BC/PDA/ZIF-8/Ag) shows satisfactory biocompatibility and promising angiogenic ability. In vivo study, the full-thickness skin defect on rats demonstrates remarkably wound healing ability and accelerated skin re-epithelialization. This work presents a competitive functional dressing with effective antibacterial properties and accelerative angiogenesis activities for wound repair.

A self-powered multifunctional dressing for active infection prevention and accelerated wound healing.

Interruption of the wound healing process due to pathogenic infection remains a major health care challenge. The existing methods for wound management require power sources that hinder their utilization outside of clinical settings. Here, a next generation of wearable self-powered wound dressing is developed, which can be activated by diverse stimuli from the patient's body and provide on-demand treatment for both normal and infected wounds. The highly tunable dressing is composed of thermocatalytic bismuth telluride nanoplates (Bi2Te3 NPs) functionalized onto carbon fiber fabric electrodes and triggered by the surrounding temperature difference to controllably generate hydrogen peroxide to effectively inhibit bacterial growth at the wound site. The integrated electrodes are connected to a wearable triboelectric nanogenerator (TENG) to provide electrical stimulation for accelerated wound closure by enhancing cellular proliferation, migration, and angiogenesis. The reported self-powered dressing holds great potential in facilitating personalized and user-friendly wound care with improved healing outcomes.

Progress and expectation of stem cell therapy for diabetic wound healing.

Impaired wound healing presents great health risks to diabetics. Encouragingly, the current clinical successfully found out meaningful method to repair wound tissue, and stem cell therapy could be an effective method for diabetic wound healing with its ability to accelerate wound closure and avoid amputation. This minireview aims at introducing stem cell therapy for facilitating tissue repair in diabetic wounds, discussing the possible therapeutic mechanism and clinical application status and problems.

A Designed Host Defense Peptide for the Topical Treatment of MRSA-Infected Diabetic Wounds.

Diabetes mellitus is a chronic disease characterized by metabolic dysregulation which is frequently associated with diabetic foot ulcers that result from a severely compromised innate immune system. The high levels of blood glucose characteristic of diabetes cause an increase in circulating inflammatory mediators, which accelerate cellular senescence and dampen antimicrobial activity within dermal tissue. In diabetic wounds, bacteria and fungi proliferate in a protective biofilm forming a structure that a compromised host defense system cannot easily penetrate, often resulting in chronic infections that require antimicrobial intervention to promote the healing process. The designed host defense peptide (dHDP) RP557 is a synthesized peptide whose sequence has been derived from naturally occurring antimicrobial peptides (AMPs) that provide the first line of defense against invading pathogens. AMPs possess an amphipathic α-helix or β-sheet structure and a net positive charge that enables them to incorporate into pathogen membranes and perturb the barrier function of Gram-positive and Gram-negative bacteria along with fungi. The capacity of skin to resist infections is largely dependent upon the activity of endogenous AMPs that provided the basis for the design and testing of RP557 for the resolution of wound infections. In the current study, the topical application of RP557 stopped bacterial growth in the biofilm of methicillin-resistant Staphylococcus aureus (MRSA) USA300 infected wounds on the flanks of clinically relevant diabetic TALLYHO mice. Topical application of RP557 reduced bacterial load and accelerated wound closure, while wound size in control diabetic mice continued to expand. These studies demonstrate that RP557 reduces or eliminates an infection in its biofilm and restores wound-healing capacity.

Neutralization of excessive CCL28 improves wound healing in diabetic mice.

Introduction: Chronic, non-healing skin wounds such as diabetic foot ulcers (DFUs) are common in patients with type 2 diabetes mellitus (T2DM) and often result in limb amputation and even death. However, mechanisms by which T2DM and inflammation negatively impact skin wound healing remains poorly understood. Here we investigate a mechanism by which an excessive level of chemokine CCL28, through its receptor CCR10, impairs wound healing in patients and mice with T2DM. Methods & Results: Firstly, a higher level of CCL28 was observed in skin and plasma in both patients with T2DM, and in obesity-induced type 2 diabetic db/db mice. Compared with WT mice, adipose tissue from db/db mice released 50% more CCL28, as well as 2- to 3-fold more IL-1β, IL-6, and TNF-α, and less VEGF, as determined by ELISA measurements. Secondly, overexpression of CCL28 with adenovirus (Adv-CCL28) caused elevation of proinflammatory cytokines as well as CCR10 expression and also reduced eNOS expression in the dorsal skin of WT mice as compared with control Adv. Thirdly, topical application of neutralizing anti-CCL28 Ab dose-dependently accelerated wound closure and eNOS expression, and decreased IL-6 level, with an optimal dose of 1 μg/wound. In addition, mRNA levels of eNOS and anti-inflammatory cytokine IL-4 were increased as shown by real-time RT-PCR. The interaction between eNOS and CCR10 was significantly reduced in diabetic mouse wounds following application of the optimal dose of anti-CCL28 Ab, and eNOS expression increased. Finally, enhanced VEGF production and increased subdermal vessel density as indicated by CD31 immunostaining were also observed with anti-CCL28 Ab. Discussion: Taken together, topical application of neutralizing anti-CCL28 Ab improved dorsal skin wound healing by reducing CCR10 activation and inflammation in part by preventing eNOS downregulation, increasing VEGF production, and restoring angiogenesis. These results indicate anti-CCL28 Ab has significant potential as a therapeutic strategy for treatment of chronic non-healing diabetic skin wounds such as DFUs.

Highly concentrated trehalose induces prohealing senescence-like state in fibroblasts via CDKN1A/p21

Trehalose is the nonreducing disaccharide of glucose, evolutionarily conserved in invertebrates. The living skin equivalent (LSE) is an organotypic coculture containing keratinocytes cultivated on fibroblast-populated dermal substitutes. We demonstrated that human primary fibroblasts treated with highly concentrated trehalose promote significantly extensive spread of the epidermal layer of LSE without any deleterious effects. The RNA-seq analysis of trehalose-treated 2D and 3D fibroblasts at early time points revealed the involvement of the CDKN1A pathway, the knockdown of which significantly suppressed the upregulation of DPT, ANGPT2, VEGFA, EREG, and FGF2. The trehalose-treated fibroblasts were positive for senescence-associated β-galactosidase. Finally, transplantation of the dermal substitute with trehalose-treated fibroblasts accelerated wound closure and increased capillary formation significantly in the experimental mouse wounds in vivo, which was canceled by the CDKN1A knockdown. These data indicate that high-concentration trehalose can induce the senescence-like state in fibroblasts via CDKN1A/p21, which may be therapeutically useful for optimal wound repair.

Dry eye disease in mice activates adaptive corneal epithelial regeneration distinct from constitutive renewal in homeostasis

Many epithelial compartments undergo constitutive renewal in homeostasis but activate unique regenerative responses following injury. The clear corneal epithelium is crucial for vision and is renewed from limbal stem cells (LSCs). Using single-cell RNA sequencing, we profiled the mouse corneal epithelium in homeostasis, aging, diabetes, and dry eye disease (DED), where tear deficiency predisposes the cornea to recurrent injury. In homeostasis, we capture the transcriptional states that accomplish continuous tissue turnover. We leverage our dataset to identify candidate genes and gene networks that characterize key stages across homeostatic renewal, including markers for LSCs. In aging and diabetes, there were only mild changes with <15 dysregulated genes. The constitutive cell types that accomplish homeostatic renewal were conserved in DED but were associated with activation of cell states that comprise "adaptive regeneration." We provide global markers that distinguish cell types in homeostatic renewal vs. adaptive regeneration and markers that specifically define DED-elicited proliferating and differentiating cell types. We validate that expression of SPARC, a marker of adaptive regeneration, is also induced in corneal epithelial wound healing and accelerates wound closure in a corneal epithelial cell scratch assay. Finally, we propose a classification system for LSC markers based on their expression fidelity in homeostasis and disease. This transcriptional dissection uncovers the dramatically altered transcriptional landscape of the corneal epithelium in DED, providing a framework and atlas for future study of these ocular surface stem cells in health and disease.

Bone marrow-derived mesenchymal stem cell-conditioned medium ameliorates diabetic foot ulcers in rats

ObjectivesThis study aimed to explore the effects of bone marrow-derived Mesenchymal Stem Cell-Conditioned Medium (MSC-CM) treating diabetic foot ulcers in rats. MethodsModels of T2DM rats were induced by a high-fat diet and intraperitoneal injection of STZ in SD rats. Models of Diabetic Foot Ulcers (DFUs) were made by operation on hind limbs in diabetic rats. Rats were divided into four groups (n = 6 for each group), i.e., Normal Control group (NC), Diabetes Control group (DM-C), MSC-CM group and Mesenchymal Stem Cells group (MSCs). MSC-CM group was treated with an injection of conditioned medium derived from preconditioned rats' bone marrow MSCs around ulcers. MSCs group were treated with an injection of rats' bone marrow MSCs. The other two groups were treated with an injection of PBS. After the treatment, wound closure, re-epithelialization (thickness of the stratum granulosums of the skin, by H&E staining), cell proliferation (Ki67, by IHC), angiogenesis (CD31, by IFC), autophagy (LC3B, by IFC and WB; autolysosome, by EM) and pyroptosis (IL-1β, NLRP3, Caspase-1, GSDMD and GSDMD-N, by WB) in ulcers were evaluated. ResultsAfter the treatment wound area rate, IL-1β by ELISA, and IL-1β, Caspase-1, GSDMD and GSDMD-N by WB of MSC-CM group were less than those of DM group. The thickness of the stratum granulosums of the skin, proliferation index of Ki67, mean optic density of CD31 and LC3B by IFC, and LC3B by WB of MSC-CM group were more than those of DM group. The present analysis demonstrated that the injection of MSC-CM into rats with DFUs enhanced the wound-healing process by accelerating wound closure, promoting cell proliferation and angiogenesis, enhancing cell autophagy, and reducing cell pyroptosis in ulcers. ConclusionsStudies conducted indicate that MSC-CM administration could be a novel cell-free therapeutic approach to treat DFUs accelerating the wound healing process and avoiding the risk of living cells therapy.