Wound Healing In Mouse Model Research Articles

Establishment and verification of a mouse model of nasal wound healing.

Poor wound healing as reflected by the development of synechia and osteitis after endoscopic sinus surgery may trigger disease recurrence. Animal models provide insights into the pathogenesis of poor wound healing and may aid in the development of new therapeutics. Here, we established a mouse model of nasal wound healing and confirmed its utility. Animal study. Unilateral intranasal wounds were induced using a small interdental brush in 6-week-old C57BL/6 mice. Forty-five mice were divided into three groups (each n = 15): one control and two experimental groups (intranasal vs. intraperitoneal dexamethasone). Mice were sacrificed on days 2, 14, and 28 after injury (each n = 5). Serial changes in nasal wound histopathology were described, and intergroup differences were analyzed. On day 2, mucosal detachment, hemorrhage, and exudate were observed. On day 14, synechiae featuring neo-osteogenesis (bone lacunae, osteoblasts, and multinucleated osteoclasts) between the septum and the maxilloturbinate were prominent, followed by wound maturation on day 28: fewer lacunae and smaller osteoblasts. Macrophages were evident only on day 2, and lymphocytes were predominant on day 28. The amount of exudate on day 2 and the synechial area on day 28 were significantly reduced in mice that received dexamethasone systemically compared with control mice, with similar trends in those treated intranasally. Our mouse model of nasal wound healing was characterized by the development of bony synechia and neo-osteogenesis, not soft-tissue synechia. The model may be useful in the assessment of novel therapeutics to prevent those wounds. NA Laryngoscope, 129:E266-E271, 2019.

A novel target for the promotion of dermal wound healing: Ryanodine receptors

Ryanodine receptors have an important role in the regulation of intracellular calcium levels in the nervous system and muscle. It has been described that ryanodine receptors influence keratinocyte differentiation and barrier homeostasis. Our goal was to examine the role of ryanodine receptors in the healing of full-thickness dermal wounds by means of in vitro and in vivo methods.The effect of ryanodine receptors on wound healing, microcirculation and inflammation was assessed in an in vivo mouse wound healing model, using skin fold chambers in the dorsal region, and in HaCaT cell scratch wound assay in vitro. SKH-1 mice were subjected to sterile saline (n = 36) or ryanodine receptor agonist 4-chloro-m-cresol (0.5 mM) (n = 42) or ryanodine receptor antagonist dantrolene (100 μM) (n = 42).Application of ryanodine receptor agonist 4-chloro-m-cresol did not influence the studied parameters significantly, whereas ryanodine receptor antagonist dantrolene accelerated the wound closure. Inhibition of the calcium channel also increased the vessel diameters in the wound edges during the process of healing and increased the blood flow in the capillaries at all times of measurement. Furthermore, application of dantrolene decreased xanthine-oxidoreductase activity during the inflammatory phase of wound healing.Inhibition of ryanodine receptor-mediated effects positively influence wound healing. Thus, dantrolene may be of therapeutic potential in the treatment of wounds.

Suppression of neovascularization in corneal stroma in a TRPA1-null mouse

Corneal neovascularization and inflammatory fibrosis induced by severe injury or infection leads to tissue opacification and even blindness. Transient receptor potential (TRP) channel subtypes contribute to mediating these maladaptive responses through their interactions with other receptors. TRPV1 is one of the contributing channel isoforms inducing neovascularization in an alkali burn mouse wound healing model. VEGF-A upregulation contributes to neovascularization through interaction with its cognate receptors (VEGFR). Since the TRP isoform in this tissue, TRPA1, is also involved, we determined here if one of the pathways mediating neovascularization and immune cell infiltration involve an interaction between VEGFR and TRPA1 in a cauterization corneal mouse wound healing model. Localization of TRPA1 and endothelial cell (EC) CD31 immunostaining pattern intensity determined if TRPA1 expression was EC delimited during cauterization induced angiogenesis. Quantitative RT-PCR evaluated the effects of the absence of TRPA1 function on VEGF-A and TGF-β1 mRNA expression during this process. Macrophage infiltration increased based on rises in F4/80 antigen immunoreactivity. TRPA1 immunostaining was absent on CD31-immunostained EC cells undergoing neovascularization, but it was present on other cell type(s) adhering to EC in vivo. Absence of TRPA1 expression suppressed both stromal neovascularization and inhibited macrophage infiltration. Similarly, the increases occurring in both VEGF-A and TGF-β1 mRNA expression levels in WT tissue were blunted in the TRPA1−/− counterpart. On the other hand, in the macrophages their levels were invariant and their infiltration was inhibited. To determine if promotion by TRPA1 of angiogenesis was dependent on its expression on other unidentified cell types, the effects were compared of pharmacological manipulation of TRPA1 activity on EC proliferation tube formation and migration. In the presence and absence of a fibroblast containing feeder layer. Neither VEGF-induced increases in human vascular endothelial cell (HUVEC) proliferation nor migration were changed by a TRPA1 antagonist HC-030031 in the absence of a feeder layer. However, on a fibroblast feeder layer this antagonist suppressed HUVEC tube formation. In conclusion, during corneal wound healing transactivation by VEGFR of TRPA1 contributes to mediating neovascularization and macrophage infiltration. Such crosstalk is possible because of close proximity between VEGFR delimited expression on EC and TRPA1 expression restricted to cell types adhering to EC.

Single-Cell Gene Expression Analysis and Evaluation of the Therapeutic Function of Murine Adipose-Derived Stromal Cells (ASCs) from the Subcutaneous and Visceral Compartment.

Introduction Adipose-derived stromal cells (ASCs) are a promising resource for wound healing and tissue regeneration because of their multipotent properties and cytokine secretion. ASCs are typically isolated from the subcutaneous fat compartment, but can also be obtained from visceral adipose tissue. The data on their equivalence diverges. The present study analyzes the cell-specific gene expression profiles and functional differences of ASCs derived from the subcutaneous (S-ASCs) and the visceral (V-ASCs) compartment. Material and Methods Subcutaneous and visceral ASCs were obtained from mouse inguinal fat and omentum. The transcriptional profiles of the ASCs were compared on single-cell level. S-ASCs and V-ASCs were then compared in a murine wound healing model to evaluate their regenerative functionality. Results On a single-cell level, S-ASCs and V-ASCs displayed distinct transcriptional profiles. Specifically, significant differences were detected in genes associated with neoangiogenesis and tissue remodeling (for example, Ccl2, Hif1α, Fgf7, and Igf). In addition, a different subpopulation ecology could be identified employing a cluster model. Nevertheless, both S-ASCs and V-ASCs induced accelerated healing rates and neoangiogenesis in a mouse wound healing model. Conclusion With similar therapeutic potential in vivo, the significantly different gene expression patterns of ASCs from the subcutaneous and visceral compartments suggest different signaling pathways underlying their efficacy. This study clearly demonstrates that review of transcriptional results in vivo is advisable to confirm the tentative effect of cell therapies.

Renal dysfunction aggravated impaired cutaneous wound healing in diabetic mice.

Renal dysfunction has been associated with poor outcomes of wound healing in the diabetic population. The purpose of this study was to create an excisional wound healing model in diabetic mice with renal dysfunction to investigate the combined effects of diabetes and nephropathy on cutaneous ulcers. Renal impairment was introduced in diabetic db/db mice through unilateral nephrectomy and electrocoagulation of the contralateral kidney. Renal function was subsequently monitored with assays of blood urea nitrogen and spot urinary protein/creatinine ratio. After 8 weeks, splinted, full-thickness excisional wounds were created on the dorsal skin and harvested on postoperative days 7 and 14 for further evaluation of wound healing. Renal injury promoted the increase of blood urea nitrogen 3 weeks after initial operation, which was maintained at double the control level throughout the study, concomitantly leading to a significant increase of spot urinary protein excretion. Diabetic mice with renal injury displayed notably impaired wound healing processes, concurrent with reductions in cellular proliferation and angiogenesis, as well as increases in M1 polarized macrophages, infiltrated neutrophils, oxidative stress, and cellular apoptosis. Furthermore, quantitative polymerase chain reaction (qPCR) results displayed corresponding changes of related genes (TNF-α, IL-1β, SOD2) in the wounds of renal injured db/db mice. Renal manipulation in this study accelerated the progress of renal impairment, which was demonstrated to aggravate impaired cutaneous wound healing in diabetic mice.

Modified VEGF-A mRNA induces sustained multifaceted microvascular response and accelerates diabetic wound healing

Capable of mediating efficient transfection and protein production without eliciting innate immune responses, chemically modified mRNA holds great potential to produce paracrine factors at a physiologically beneficial level, in a spatiotemporally controlled manner, and with low toxicity. Although highly promising in cardiovascular medicine and wound healing, effects of this emerging therapeutic on the microvasculature and its bioactivity in disease settings remain poorly understood. Here, we longitudinally and comprehensively characterize microvascular responses to AZD8601, a modified mRNA encoding vascular endothelial growth factor A (VEGF-A), in vivo. Using multi-parametric photoacoustic microscopy, we show that intradermal injection of AZD8601 formulated in a biocompatible vehicle results in pronounced, sustained and dose-dependent vasodilation, blood flow upregulation, and neovessel formation, in striking contrast to those induced by recombinant human VEGF-A protein, a non-translatable variant of AZD8601, and citrate/saline vehicle. Moreover, we evaluate the bioactivity of AZD8601 in a mouse model of diabetic wound healing in vivo. Using a boron nanoparticle-based tissue oxygen sensor, we show that sequential dosing of AZD8601 improves vascularization and tissue oxygenation of the wound bed, leading to accelerated re-epithelialization during the early phase of diabetic wound healing.

Interleukin-33 encourages scar formation in murine fetal skin wounds.

The magnitude of the inflammatory response after skin injury is important for determining whether wounds in developing fetal skin will heal scarlessly (minimal inflammation) or with prominent scars (robust inflammation). One class of inflammatory mediators gaining attention for their role in wound inflammation is alarmins. In the current study, the alarmin interleukin-33 (IL-33) was examined in a mouse model of fetal wound healing. IL-33 expression was elevated in scar-forming embryonic day 18 wounds compared to scarless embryonic day 15 wounds. Furthermore, injection of IL-33 into embryonic day 15 wounds caused scarring when wounds were analyzed at 7 days postwounding. The introduction of IL-33 into embryonic day 15 wounds did not induce statistically significant changes in the number of neutrophils, mast cells, or macrophages in vivo. However, IL-33 treatment enhanced collagen expression in cultured fibroblasts derived from adult and fetal murine skin, suggesting that IL-33 may directly stimulate fibroblasts. In vitro studies suggested that the stimulation of collagen production by IL-33 in fibroblasts was partially dependent on NF-κB activation. Overall, the data suggest an association between IL-33 and scar formation in fetal wounds.

Long noncoding RNA-antisense noncoding RNA in the INK4 locus accelerates wound healing in diabetes by promoting lymphangiogenesis via regulating miR-181a/Prox1 axis.

Slow lymphangiogenesis is one crucial reason for the impaired wound healing process in diabetes. Accumulative evidence showed that long noncoding RNA-antisense noncoding RNA in the INK4 locus (ANRIL) could influence lymphangiogenesis. Besides, miR-181a has been reported to regulate Prox1 that is essential for lymphangiogenesis. However, the relationship between ANRIL and miR-181a as well as the definitive function of ANRIL in lymphangiogenesis is not clear. The diabetic mouse model was set up to assess the wound healing rate in vivo. Quantitative real-time polymerase chain reaction was performed to measure the expressions of ANRIL, miR-181a, and Prox1. Western blot analysis was used to assess the expressions of vascular endothelial growth factor receptor-3,lymphatic vessel hyaluronan receptor-1, Prox1, and epithelial-mesenchymal transition (EMT)-related proteins. Flow cytometry was used to assess the cell apoptosis. Wound healing assay was used to determine the effect of ANRIL on cell migration. Tube-formation assay and immunofluorescence staining were performed to determine tube-formation capacity of human dermal lymphatic endothelial cells (LECs). ANRIL and Prox1 were downregulated, whereas miR-181a was upregulated in the diabetic wound healing mouse model and high glucose (HG)-induced LECs. The wound healing rate and EMT were inhibited during the diabetic wound healing process. Dual-luciferase assay proved that miR-181a could bind Prox1 to repress its expression, whereas ANRIL could sponge miR-181a to recover Prox1 expression. Overexpression of ANRIL or inhibition of miR-181a rescued the impairments of survival, migration, EMT formation, and tube formation of LECs caused by HG. ANRIL could promote lymphangiogenesis during the diabetic wound healing process via sponging miR-181a to enhance Prox1 expression, which might help design new therapy to improve the wound healing efficacy for diabetes.

Curcumin promotes burn wound healing in mice by upregulating caveolin-1 in epidermal stem cells.

We aimed to explore the effect of curcumin on epidermal stem cells (ESCs) in regulating wound healing and the underlying molecular mechanism. We treated mouse ESCs isolated from skin tissues with curcumin, and then assessed the proliferation ability of cells induced by epidermal growth factor using cell counting kit-8 assay. The pluripotency of ESCs was evaluated as well through examination of Nanog expression in ESCs. Further, mice with skin burns were treated with ESCs with or without curcumin pretreatments. Histological evaluations were then preformed to determine wound scores, cell proliferation, reepithelialization, and capillary density in wounds. Curcumin treatment promoted the proliferative ability of ESCs and conditioned medium from curcumin-treated ESCs enhanced human umbilical vein endothelial cell (HUVEC) tube formation. We also found curcumin treatment elevated caveolin-1 expression in ESCs, which was required for the beneficial effect of curcumin on ESC proliferation and HUVEC tube formation. Next, using a mouse model of burn wound healing, curcumin-treated ESCs exhibited enhanced wound closure, which also required caveolin-1 expression. Our current study demonstrates the beneficial effect of curcumin on burn wound healing in mice, which is mediated by upregulating caveolin-1 in ESCs, and supports the potential therapeutic role of curcumin in ESC-based treatment against skin wound healing.

Polyvinylpyrrolidone/hyaluronic acid-based bilayer constructs for sequential delivery of cutaneous antiseptic and antibiotic

After a skin injury, many complex metabolic events are triggered to ensure proper wound healing. Particularly for chronic, non-healing wounds or burns several risk factors such as persistent bacterial infections and fast dehydration can counteract the healing process. Intelligent wound dressings should help accelerate the healing process, while maintaining the wound bed clean and disinfected for several days at a time. Ideally, they should be self-adherent to both moist and dry skin surfaces and be transparent enough to allow prolonged wound inspection. These requirements pose challenges both in terms of materials science and pharmaceutics. Herein, we describe fabrication of a transparent bilayer construct for the sequential release and delivery of a cutaneous antiseptic and a widely used antibiotic, potentially suitable for wound dressing applications. The fabrication is a scalable waterborne and ecofriendly solution casting process. The first layer (for direct wound contact) is polyvinylpyrrolidone (PVP) containing a commercial antiseptic, Neomercurocromo® (Neo), while the second layer is a blend of hyaluronic acid (HA) and PVP containing ciprofloxacin. We show that the bilayer films have satisfactory self-adhering strength to human skin and that PVP and HA can interact via hydrogen bonds causing sustained release of the antibiotic over a period of 5 days. Biocompatibility was demonstrated on human foreskin fibroblast HFF-1 cells. Antibacterial activity was evaluated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa while the wound resorption behavior was assessed through an in vivo full-thickness excisional wound healing mice model. These observations indicate that such bilayer constructs can be potentially implemented as wound care products for diverse range of skin wounds, including large area skin infections.

An effective range of polydeoxyribonucleotides is critical for wound healing quality

Wound healing is a physiological restorative response to tissue and cell injury. This process occurs in collaboration with a complex cascade of cellular events, including biochemical alterations to the extracellular matrix. Polydeoxyribonucleotide (PDRN) is a fragmented DNA mixture from Oncorhynchus mykiss or Oncorhynchus keta sperm known to promote tissue regeneration under different pathophysiological conditions. However, the most effective molecular size of PDRNs for promoting the wound healing process and quality has not been established. In the present study, the regeneration quality with low (<50kDa), middle [classic PDRN; 50‑1,500kDa] and high (>1,500kDa) molecular weight PDRNs in a skin wound healing mouse model was examined using hematoxylin and eosin, as well as Masson's trichrome stain. A 4mm biopsy punch was used to produce wounds in the skin of the mice. PDRN‑mediated cellular behavior and signaling were evaluated by invitro scratch assay and western blot analysis, respectively. It was observed that the apparent surface wound healing processes were not significantly different between PDRN molecular sizes. Immunohistochemical analysis revealed that classic PDRN‑injected mice exhibited less lipid accumulation with increased collagen composition. These results suggested that 50‑1,500kDa PDRN offers an effective DNA mixture to improve wound healing quality. Furthermore, classic PDRN increased cell migration via c‑Jun N‑terminal kinase signaling in human fibroblasts. The present study suggests an optimal PDRN molecular weight to promote wound healing, and novel approaches for therapeutic strategies to improve tissue regeneration quality.

Effect of N-acyl-dopamines on beta cell differentiation and wound healing in diabetic mice

N-acyl-dopamines are endolipids with neuroprotective, antiinflammatory and immunomodulatory properties. Previously, we showed the ability of these compounds to induce HIF-1α stabilization. Hypoxia and HIF-1α play an important role in the most relevant stages of diabetic pathogenesis. This work analyzes the possible role of these molecules on beta cell differentiation, insulin production and diabetic foot ulcer. Hypoxia response pathway has been characterized in beta-cell differentiation in rat pancreatic acinar cell line and human islet-derived precursor cells. Protein and mRNA expression of key proteins in this process have been analyzed, as well as those involved in beta cells reprogramming. The effect of N-acyl-dopamines on hypoxia response pathway, beta cells reprogramming and insulin production have been studied in both cell types, as well as its role in angiogenesis models in vitro and wound closure in type 2 diabetic mice. Our results show how the hypoxia response pathway is altered during beta cells differentiation, accompanied by an induction of the transcription factor HIF-1α. We demonstrate how some N-acyl-dopamines induce beta cell differentiation and insulin production in two different cell models. In parallel, these endolipids promote angiogenesis in vitro and wound closure in type 2 diabetic mice. These results provide a biological mechanism through which some endolipids could induce beta cell differentiation. We demonstrate how N-acyl-dopamines can modulate insulin production and, in parallel, reverse HIF-1α inhibition in a wound healing model in diabetic mice. Therefore, the potential use of the pharmacological modulation of N-acyl-dopamines may have implications for diabetes prevention and treatment strategies.

Knockdown of the KINDLIN-2 Gene and Reduced Expression of Kindlin-2 Affects Vascular Permeability in Angiogenesis in a Mouse Model of Wound Healing.

BackgroundAngiogenesis is an important component of wound healing and tissue repair. Kindlin-2 is an integrin-associated protein, encoded by the KINDLIN-2 gene, which has been shown to affect cell adhesion and migration of cells, including endothelial cells. The aim of this study was to use a mouse model of wound healing to evaluate the effects of expression of KINDLIN-2 on angiogenesis in wound healing in vivo.Material/MethodsThirty-six male C57BL/6 mice were studied in an established model that used a wound created on the back. Mice were divided randomly into three groups: the normal group (n=12) received injections of normal (0.9%) saline; the KINDLIN-2(−) group (n=12) received injections of adeno-associated virus with small interfering (si)RNA targeting the KINDLIN-2 gene (AAV-KINDLIN-2-siRNA); and the control (group (n=12) received injections of adeno-associated virus containing a scrambled RNA sequence (AAV-control-RNA). Wound healing was analyzed by biochemical examination of the exudates and histology. Evans blue dye was injected into the caudal vein of each mouse, two weeks after wound healing to assess neovascular permeability.ResultsWound healing was significantly delayed in the KINDLIN-2 gene knockdown mice (AAV-KINDLIN-2-siRNA) compared with that of the normal group and the control group, and neovascular permeability was increased. In the AAV-KINDLIN-2-siRNA group, blood vessels were shorter and thinner compared with the normal group and the control group.ConclusionsIn a mouse model of wound healing, KINDLIN-2 gene knockdown inhibited wound healing, and increased neovascular permeability in vivo.

Acceleration of Diabetic Wound Healing with PHD2- and miR-210-Targeting Oligonucleotides.

In diabetes-associated chronic wounds, the normal response to hypoxia is impaired and many cellular processes involved in wound healing are hindered. Central to the hypoxia response is hypoxia-inducible factor-1α (HIF-1α), which activates multiple factors that enhance wound healing by promoting cellular motility and proliferation, new vessel formation, and re-epithelialization. Prolyl hydroxylase domain-containing protein 2 (PHD2) regulates HIF-1α activity by targeting it for degradation under normoxia. HIF-1α also upregulates microRNA miR-210, which in turn regulates proteins involved in cell cycle control, DNA repair, and mitochondrial respiration in ways that are antagonistic to wound repair. We have identified a highly potent short synthetic hairpin RNA (sshRNA) that inhibits expression of PHD2 and an antisense oligonucleotide (antimiR) that inhibits miR-210. Both oligonucleotides were chemically modified for improved biostability and to mitigate potential immunostimulatory effects. Using the sshRNA to silence PHD2 transcripts stabilizes HIF-1α and, in combination with the antimiR targeting miR-210, increases proliferation and migration of keratinocytes in vitro. To assess activity and delivery in an impaired wound healing model in diabetic mice, PHD2-targeting sshRNAs and miR-210 antimiRs both alone and in combination were formulated for local delivery to wounds using layer-by-layer (LbL) technology. LbL nanofabrication was applied to incorporate sshRNA into a thin polymer coating on a Tegaderm mesh. This coating gradually degrades under physiological conditions, releasing sshRNA and antimiR for sustained cellular uptake. Formulated treatments were applied directly to splinted full-thickness excisional wounds in db/db mice. Cellular uptake was confirmed using fluorescent sshRNA. Wounds treated with a single application of PHD2 sshRNA or antimiR-210 closed 4 days faster than untreated wounds, and wounds treated with both oligonucleotides closed on average 4.75 days faster. Markers for neovascularization and cell proliferation (CD31 and Ki67, respectively) were increased in the wound area following treatment, and vascular endothelial growth factor (VEGF) was increased in sshRNA-treated wounds. Our results suggest that silencing of PHD2 and miR-210 either together or separately by localized delivery of sshRNAs and antimiRs is a promising approach for the treatment of chronic wounds, with the potential for rapid clinical translation.

MicroRNA-148b Targets the TGF-β Pathway to Regulate Angiogenesis and Endothelial-to-Mesenchymal Transition during Skin Wound Healing.

Transforming growth factor beta (TGF-β) is crucial for regulation of the endothelial cell (EC) homeostasis. Perturbation of TGF-β signaling leads to pathological conditions in the vasculature, causing cardiovascular disease and fibrotic disorders. The TGF-β pathway is critical in endothelial-to-mesenchymal transition (EndMT), but a gap remains in our understanding of the regulation of TGF-β and related signaling in the endothelium. This study applied a gain- and loss-of function approach and an in vivo model of skin wound healing to demonstrate that miR-148b regulates TGF-β signaling and has a key role in EndMT, targeting TGFB2 and SMAD2. Overexpression of miR-148b increased EC migration, proliferation, and angiogenesis, whereas its inhibition promoted EndMT. Cytokine challenge decreased miR-148b levels in ECs while promoting EndMT through the regulation of SMAD2. Finally, in a mouse model of skin wound healing, delivery of miR-148b mimics promoted wound vascularization and accelerated closure. In contrast, inhibition of miR-148b enhanced EndMT in wounds, resulting in impaired wound closure that was reversed by SMAD2 silencing. Together, these results demonstrate for the first time that miR-148b is a key factor controlling EndMT and vascularization. This opens new avenues for therapeutic application of miR-148b in vascular and tissue repair.

Compressed Collagen Enhances Stem Cell Therapy for Corneal Scarring.

Stem cells from human corneal stroma (CSSC) suppress corneal stromal scarring in a mouse wound‐healing model and promote regeneration of native transparent tissue (PMID:25504883). This study investigated efficacy of compressed collagen gel (CCG) as a vehicle to deliver CSSC for corneal therapy. CSSC isolated from limbal stroma of human donor corneas were embedded in soluble rat‐tendon collagen, gelled at 37°C, and partially dehydrated to a thickness of 100 µm by passive absorption. The CCG disks were dimensionally stable, easy to handle, and could be adhered securely to de‐epithelialized mouse cornea with fibrin‐based adhesive. CSSC in CCG maintained >80% viability for >1 week in culture media and could be cryopreserved in 20% fetal bovine serum‐10%DMSO in liquid nitrogen. CCG containing as few as 500 CSSC effectively prevented visible scarring and suppressed expression of fibrotic Col3a1 mRNA. CSSC in CCG were more effective at blocking scarring on a per‐cell basis than CSSC delivered directly in a fibrin gel as previously described. Collagen‐embedded cells retained the ability to suppress corneal scarring after conventional cryopreservation. This study demonstrates use of a common biomaterial that can facilitate storage and handling of stem cells in a manner that may provide off‐the‐shelf delivery of stem cells as a therapy for corneal scarring. stem cells translational medicine 2018;7:487–494

Can wound healing worsen metastasis?

Cancer Early metastatic recurrence in breast cancer patients could be caused by tumor cells released into the circulation during primary resection or could be the result of existing metastatic outgrowth. To distinguish between these possibilities, Krall et al. used a common wound-healing model in mice harboring breast cancer cells in which the primary tumor bed was not disturbed by surgery. They found that T cells can keep tumor cells in check, but if wound healing is induced, inflammation disrupts this balance. Anti-inflammatory treatment reduced metastasis in the mice. Existing clinical data indicate that perioperative anti-inflammatories reduce early metastatic recurrence in breast cancer patients. By separating surgery from resection, these results may explain this curious clinical occurrence. Sci. Transl. Med. 10 , eaan3464 (2018).

Airborne particulate matter impairs corneal epithelial cells migration via disturbing FAK/RhoA signaling pathway and cytoskeleton organization

Background: Cornea is the outmost structure of the eye and exposed directly to the air pollution. However, little is known about the effect of PM2.5 on corneal epithelium, which is critical for maintenance of cornea homeostasis and visual function.Objective: We investigated the influence of PM2.5 exposure on corneal epithelial migration and the possible mechanisms involved in the process.Methods: We observed wound healing in mouse model of cornea abrasion, evaluated the migration and mobility of cultured corneal epithelial cells with wound scratch assay and Transwell migration assay, detected the phosphorylation and interaction of FAK/paxillin with immunofluorescence and immunoprecipitation, and determined the RhoA activity and actin reorganization, in response to PM2.5 exposure.Results: Exposure to PM2.5 remarkably inhibited corneal epithelial cell migration both in mouse model of corneal abrasion and in cell culture model. We found the phosphorylation and interaction of FAK/paxillin, RhoA activity as well as actin reorganization were suppressed by PM2.5 exposure. Moreover, formation of ROS might play a role in the action of PM2.5.Conclusions: PM2.5 exposure could result in delay of corneal epithelium wound healing by inhibiting cell migration, thus more attention should be paid to the potential risk of corneal infection and effort should be made to protect eyes against impairment induced by PM2.5

Injury-activated glial cells promote wound healing of the adult skin in mice

Cutaneous wound healing is a complex process that aims to re-establish the original structure of the skin and its functions. Among other disorders, peripheral neuropathies are known to severely impair wound healing capabilities of the skin, revealing the importance of skin innervation for proper repair. Here, we report that peripheral glia are crucially involved in this process. Using a mouse model of wound healing, combined with in vivo fate mapping, we show that injury activates peripheral glia by promoting de-differentiation, cell-cycle re-entry and dissemination of the cells into the wound bed. Moreover, injury-activated glia upregulate the expression of many secreted factors previously associated with wound healing and promote myofibroblast differentiation by paracrine modulation of TGF-β signalling. Accordingly, depletion of these cells impairs epithelial proliferation and wound closure through contraction, while their expansion promotes myofibroblast formation. Thus, injury-activated glia and/or their secretome might have therapeutic potential in human wound healing disorders.

Hydroxypropyltrimethyl Ammonium Chloride Chitosan Functionalized-PLGA Electrospun Fibrous Membranes as Antibacterial Wound Dressing: In Vitro and In Vivo Evaluation.

A novel poly(lactic-co-glycolic acid) (PLGA)-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) composite nanofiber wound dressing was prepared through electrospinning and the entrapment-graft technique as an antibacterial dressing for cutaneous wound healing. HACC with 30% degrees of substitution (DS) was immobilized onto the surface of PLGA membranes via the reaction between carboxyl groups in PLGA after alkali treatment and the reactive groups (–NH2) in HACC molecules. The naked PLGA and chitosan graft PLGA (PLGA-CS) membranes served as controls. The surface immobilization was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and energy dispersive X-ray spectrometry (EDX). The morphology studies showed that the membranes remain uniform after the immobilization process. The effects of the surface modification by HACC and CS on the biological properties of the membranes were also investigated. Compared with PLGA and PLGA-CS, PLGA-HACC exhibited more effective antibacterial activity towards both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacteria. The newly developed fibrous membranes were evaluated in vitro for their cytotoxicity using human dermal fibroblasts (HDFs) and human keratinocytes (HaCaTs) and in vivo using a wound healing mice model. It was revealed that PLGA-HACC fibrous membranes exhibited favorable cytocompatibility and significantly stimulated adhesion, spreading and proliferation of HDFs and HaCaTs. PLGA-HACC exhibited excellent wound healing efficacy, which was confirmed using a full thickness excision wound model in S. aureus-infected mice. The experimental results in this work suggest that PLGA-HACC is a strong candidate for use as a therapeutic biomaterial in the treatment of infected wounds.