A suprapubic refractory skin ulcer following keloid radiotherapy: from hyper-proliferation to hypo-proliferation.

Radiation-induced skin ulcer following cancer and/or tumour is well-documented in the literature. However, radiation-induced skin ulcer following the excision of keloid is yet to be reported. Here, we report the case of a 33-year-old female patient with a suprapubic skin ulcer of five months' duration following keloid treatment with electron beam therapy at recommended dosage. Various examinations, including a skin biopsy, metagenomic sequencing, magnetic resonance imaging and immunochemistry, indicated that the skin ulcer was induced by radiotherapy. While postoperative radiotherapy has been recommended immediately following keloid excision to reduce the risk of recurrence, the present case highlights the risk of skin refractory ulcer following keloid radiotherapy.

Hybrid Autologous Costal Cartilage Grafting for Augmentation Rhinoplasty in Asian Patients.

BACKGROUND: Autologous costal cartilage has been used for augmentation rhinoplasty in Asia for many years. This study aimed to assess the effectiveness and safety of hybrid grafting of costal cartilage for dorsal augmentation, septal reconstruction, and tip augmentation for Asian patients. METHODS: A surgical technique was introduced and patients having rhinoplasty using this technique from April 2020 to March 2021 were retrospectively studied. In this technique, costal cartilage was meticulously carved or diced and grafted in various ways mainly based on the anatomic characteristics of nasal skin and subcutaneous soft tissues as well as bone and cartilage framework. The surgical outcomes, patient satisfaction, and complications retrieved from the documented medical records were reviewed and analyzed. RESULTS: Twenty-five patients having rhinoplasty with the proposed technique were followed up from 6 months to 12 months. As for cosmetic outcomes, 21 patients were graded as good, 3 patients were graded as fair, and only 1 patient was graded as poor. Those patients who were not graded as good had over-rotated tips, insufficient dorsal augmentation, or asymmetry of nostrils and soft tissue contracture. The overall patient satisfaction was as high as 96.0%. Local infection occurred in 1 patient and hematoma was not observed. Warping and visibility of costal cartilage were not observed in any patients. Slight displacement of diced cartilages was found in 2 patients near the radix 1 week postoperatively. CONCLUSIONS: Hybrid autologous costal cartilage grafts can be used for both tip refinement and dorsal augmentation for East Asian patients and achieve an outcome of a natural-looking nose with minimal complications. LEVEL OF EVIDENCE: Level IV.

Skin-resident natural killer T cells participate in cutaneous allergic inflammation in atopic dermatitis.

BACKGROUND: Natural killer T (NKT) cells are unconventional T cells that bridge innate and adaptive immunity. NKT cells have been implicated in the development of atopic dermatitis (AD). OBJECTIVE: We aimed to investigate the role of NKT cells in AD development, especially in skin. METHODS: Global proteomic and transcriptomic analyses were performed by using skin and blood from human healthy-controls and patients with AD. Levels of CXCR4 and CXCL12 expression in skin NKT cells were analyzed in human AD and mouse AD models. By using parabiosis and intravital imaging, the role of skin CXCR4+ NKT cells was further evaluated in models of mice with AD by using CXCR4-conditionally deficient or CXCL12 transgenic mice. RESULTS: CXCR4 and its cognate ligand CXCL12 were significantly upregulated in the skin of humans with AD by global transcriptomic and proteomic analyses. CXCR4+ NKT cells were enriched in AD skin, and their levels were consistently elevated in our models of mice with AD. Allergen-induced NKT cells participate in cutaneous allergic inflammation. Similar to tissue-resident memory T cells, the predominant skin NKT cells were CXCR4+ and CD69+. Skin-resident NKT cells uniquely expressed CXCR4, unlike NKT cells in the liver, spleen, and lymph nodes. Skin fibroblasts were the main source of CXCL12. CXCR4+ NKT cells preferentially trafficked to CXCL12-rich areas, forming an enriched CXCR4+ tissue-resident NKT cells/CXCL12+ cell cluster that developed in acute and chronic allergic inflammation in our models of mice with AD. CONCLUSIONS: CXCR4+ tissue-resident NKT cells may form a niche that contributes to AD, in which CXCL12 is highly expressed.

A Composite Tissue Flap for Double-Eyelid Blepharoplasty in Asian Patients: A Retrospective Study.

ABSTRACT: Double-eyelid blepharoplasty, the procedure to create supratarsal crease, has been one of the most popular cosmetic operations in Asia for many years. This study aimed to assess the effectiveness and safety of a surgical procedure using a composite tissue flap for double-eyelid blepharoplasty. A surgical technique was introduced and patients having blepharoplasty with this technique from January 2017 to August 2019 were retrospectively studied. In this technique, a composite tissue flap consisted of the posterior septum and levator aponeurosis was formed and fixed with orbicularis oculi muscle and tarsus. The cosmetic outcomes, patient satisfaction, and complications from the documented medical records were analyzed. Eighty female and 1 male patients had blepharoplasty with the proposed technique and were followed up from 6 months to 42 months. Six patients were found to have mild blepharoptosis. As for cosmetic outcomes, 71patients were graded as good, 7 patients were graded as fair, and only 1 patient was graded as poor. Those patients who were not graded as good had visible scarring, shallow eyelid crease, or asymmetry. The overall patient satisfaction was as high as 95.1%. Mild hematoma formation occurred in 3 patients and no infection or blepharoptosis was observed. One patient complained of asymmetry and 2 patients complained of unilateral crease fading as the complications. The technique is effective to develop durable and natural-looking double eyelids with minimal complications. It could also be an option for mild ptotic patients who ask for double-eyelid blepharoplasty.

Blockade of lncRNA-ASLNCS5088-enriched exosome generation in M2 macrophages by GW4869 dampens the effect of M2 macrophages on orchestrating fibroblast activation.

In hypertrophic scar (HS) formation, the type 2 immune response induces the alternatively activated macrophages (M2), which manipulate fibroblasts to differentiate into myofibroblasts with active biologic functions and proliferation. Myofibroblasts express α-smooth muscle actin (α-SMA) and synthesize and produce additional collagen type I and collagen type III, inducing HS formation. However, studies on the mechanism of M2 macrophage modulation are only based on the recognition of profibrotic factors such as TGF-ß1 secreted by macrophages. The influence of exosomes from M2 macrophages on scar formation is still unknown. Both M2 macrophages and myofibroblasts highly express glutaminases (GLSs). GLS is a critical enzyme in glutaminolysis and is important for M2 macrophage and fibroblast polarization. In this study, we found that in a TGF-ß1-stimulated coculture system, a long noncoding RNA (lncRNA) named lncRNA-ASLNCS5088 was enriched in M2 macrophage-derived exosomes. This lncRNA could be transferred with high efficiency to fibroblasts and acted as an endogenous sponge to adsorb microRNA-200c-3p, resulting in increased GLS and α-SMA expression. Pretreatment with GW4869, which impairs M2 macrophage exosome synthesis, ameliorated these pathologic changes in fibroblasts in vitro. Local injection in the late scar formation period with GW4869 reduced α-SMA+ fibroblasts and alleviated the fibrosis of tissue after wound healing in vivo.-Chen, J., Zhou, R., Liang, Y., Fu, X., Wang, D., Wang, C. Blockade of lncRNA-ASLNCS5088-enriched exosome generation in M2 macrophages by GW4869 dampens the effect of M2 macrophages on orchestrating fibroblast activation.

Effect of Netrin-1 Anti-Inflammatory Factor on Acute Lung Injury in Sepsis Rats.

BACKGROUND Acute lung injury (ALI) often occurs early and seriously in the progress of sepsis. Netrin-1 is demonstrated to be an effective anti-inflammatory agent. However, whether netrin-1 can relieve sepsis-induced ALI remains unknown. MATERIAL AND METHODS The sepsis rat model was built with the method of cecal ligation and puncture (CLP). The lung tissue changes were represented as the results of hematoxylin-eosin (HE) staining, wet-to-dry (W/D) ratio, Western blot analysis, and immunohistochemistry. An in vitro lung injury model was simulated with LPS-induced BEAS-2B cells. The cell transfection effects were evaluated by Western blot analysis and RT-qPCR analysis. TNF-alpha, IL-1ß, and IL-6 levels were detected by Western blot analysis in LPS-induced BEAS-2B cells. RESULTS Obvious inflammation caused by sepsis appeared in lung tissues with the increase of the W/D ratio and expression of inflammatory cytokines. Netrin-1 and its receptor UNC5B were reduced in sepsis. However, upregulation of netrin-1 alleviated the levels of inflammation and increased the UNC5B levels in BEAS-2B cells. CONCLUSIONS Netrin-1 protects against ALI in sepsis rats through its anti-inflammation effect and may provide a novel treatment to prevent lung injury caused by sepsis.

Staged development of long-lived T-cell receptor αß TH17 resident memory T-cell population to Candida albicans after skin infection.

BACKGROUND: Candida albicans is a dimorphic fungus to which human subjects are exposed early in life, and by adulthood, it is part of the mycobiome of skin and other tissues. Neonatal skin lacks resident memory T (TRM) cells, but in adults the C albicans skin test is a surrogate for immunocompetence. Young adult mice raised under specific pathogen-free conditions are naive to C albicans and have been shown recently to have an immune system resembling that of neonatal human subjects. OBJECTIVE: We studied the evolution of the adaptive cutaneous immune response to Candida species. METHODS: We examined both human skin T cells and the de novo and memory immune responses in a mouse model of C albicans skin infection. RESULTS: In mice the initial IL-17-producing cells after C albicans infection were dermal γδ T cells, but by day 7, αß TH17 effector T cells were predominant. By day 30, the majority of C albicans-reactive IL-17-producing T cells were CD4 TRM cells. Intravital microscopy showed that CD4 effector T cells were recruited to the site of primary infection and were highly motile 10 days after infection. Between 30 and 90 days after infection, these CD4 T cells became increasingly sessile, acquired expression of CD69 and CD103, and localized to the papillary dermis. These established TRM cells produced IL-17 on challenge, whereas motile migratory memory T cells did not. TRM cells rapidly clear an infectious challenge with C albicans more effectively than recirculating T cells, although both populations participate. We found that in normal human skin IL-17-producing CD4+ TRM cells that responded to C albicans in an MHC class II-restricted fashion could be identified readily. CONCLUSIONS: These studies demonstrate that C albicans infection of skin preferentially generates CD4+ IL-17-producing TRM cells, which mediate durable protective immunity.

Collective dipole behavior and unusual morphotropic phase boundary in ferroelectric Pb(Zr(0.5)Ti(0.5))O3 nanowires.

Dipole collective behavior and phase transition in ferroelectric (FE) Pb(Zr(0.5)Ti(0.5))O(3) nanowires, caused by modulated electric fields, are reported. Our result also leads to the finding of a rather outstanding electromechanical d(31) response in a 8.4 nm diameter PZT wire, which may potentially outperform bulk PMN-PT and PZN-PT. Moreover, we further demonstrate the existence of a new type of morphotropic phase boundary (MPB) that bridges two dissimilar structure phases of different order parameters. Microscopic insights for understanding the collective behavior and the structural phase within the new MPB are provided.

Microfluidic sweat patch based on capillary force and evaporation pump for real-time continuous sweat analysis.

In addition to the common blood and urine, fresh sweat contains a diverse range of physiological indicators that can effectively reflect changes in the body's state. Wearable sweat sensors are crucial for understanding human physiological health; however, real-time in situ measurement of multiple biomarkers in sweat remains a significant challenge. Here, we propose a wearable microfluidic patch featuring an integrated microfluidic channel and evaporation pump for accelerated and continuous sweat collection, eliminating the need for additional sweat storage cavities that typically impede real-time detection. Capillary forces are harnessed to facilitate the rapid flow of sweat through the detection area, while an evaporation pump based on porous laser-induced graphene enhances sweat evaporation. The synergistic integration of these two components enables an uninterrupted flow of fresh sweat within the patch, ensuring real-time monitoring. The influence of channel size parameters on sweat flow velocity is analyzed, and the optimal width-to-height ratio for achieving the desired flow velocity is determined. By implementing a multi-channel parallel design with chamfering, liquid flow resistance is effectively reduced. Furthermore, the patch integrates sensor modules for sodium ion, chloride ion, glucose, and pH value measurements, ensuring excellent sealing and stability of the assembled system. This work presents a simplified approach to developing wearable sweat sensors that hold the potential for health monitoring and disease diagnosis.

HSP70 alleviates sepsis-induced cardiomyopathy by attenuating mitochondrial dysfunction-initiated NLRP3 inflammasome-mediated pyroptosis in cardiomyocytes.

Background: Sepsis-induced cardiomyopathy (SIC) is an identified serious complication of sepsis that is associated with adverse outcomes and high mortality. Heat shock proteins (HSPs) have been implicated in suppressing septic inflammation. The aim of this study was to investigate whether HSP70 can attenuate cellular mitochondrial dysfunction, exuberated inflammation and inflammasome-mediated pyroptosis for SIC intervention. Methods: Mice with cecal ligation plus perforation (CLP) and lipopolysaccharide (LPS)-treated H9C2 cardiomyocytes were used as models of SIC. The mouse survival rate, gross profile, cardiac function, pathological changes and mitochondrial function were observed by photography, echocardiography, hematoxylin-eosin staining and transmission electron microscopy. In addition, cell proliferation and the levels of cardiac troponin I (cTnI), interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) were determined by Cell Counting Kit-8, crystal violet staining and enzyme-linked immunosorbent assay. Moreover, mitochondrial membrane potential was assessed by immunofluorescence staining, and dynamin-related protein 1 and pyroptosis-related molecules [nucleotide-binding domain, leucine-rich-repeat containing family pyrin domain-containing 3 (NLRP3), caspase-1, gasdermin-D (GSDMD), gasdermin-D N-terminal (GSDMD-N)] were measured by western blotting, immunoprecipitation and immunoblotting. Finally, hsp70.1 knockout mice with CLP were used to verify the effects of HSP70 on SIC and the underlying mechanism. Results: Models of SIC were successfully established, as reduced consciousness and activity with liparotrichia in CLP mice were observed, and the survival rate and cardiac ejection fraction (EF) were decreased; conversely, the levels of cTnI, TNF-α and IL-1ß and myocardial tissue damage were increased in CLP mice. In addition, LPS stimulation resulted in a reduction in cell viability, mitochondrial destabilization and activation of NLRP3-mediated pyroptosis molecules in vitro. HSP70 treatment improved myocardial tissue damage, survival rate and cardiac dysfunction caused by CLP. Additionally, HSP70 intervention reversed LPS-induced mitochondrial destabilization, inhibited activation of the NLRP3 inflammasome, caspase-1, GSDMD and GSDMD-N, and decreased pyroptosis. Finally, knockout of hsp70.1 mice with CLP aggravated cardiac dysfunction and upregulated NLRP3 inflammasome activity, and exogenous HSP70 significantly rescued these changes. It was further confirmed that HSP70 plays a protective role in SIC by attenuating mitochondrial dysfunction and inactivating pyroptotic molecules. Conclusions: Our study demonstrated that mitochondrial destabilization and NLRP3 inflammasome activation-mediated pyroptosis are attributed to SIC. Interestingly, HSP70 ameliorates sepsis-induced myocardial dysfunction by improving mitochondrial dysfunction and inhibiting the activation of NLRP3 inflammasome-mediated pyroptosis, and such a result may provide approaches for novel therapies for SIC.

Ulinastatin improves pulmonary function in severe burn-induced acute lung injury by attenuating inflammatory response.

BACKGROUND: Acute systemic inflammatory response to severe skin burn injury mediates burn-induced acute lung injury. Ulinastatin is potentially an effective intervention, because it attenuates the systemic inflammatory response induced by endotoxin and improves myocardial function during ischemic shock and reperfusion. METHODS: Rats received full-thickness burn wounds to 30% total body surface area followed by delayed resuscitation. The treatment group received 50,000 U/kg of ulinastatin and the burn group was given vehicle only. A sham group was not burned but otherwise was treated identically. After killing, blood and lung samples were harvested for histology and measurement of inflammatory mediators. RESULTS: Administration of ulinastatin significantly decreased the mRNA and protein levels of tumor necrosis factor-alpha, interleukin-1ß, -6, and -8 both locally and systemically in burn-injured rats. The secretion of neutrophil elastase and myeloperoxidase in the lung and the expression of intercellular adhesion molecule-1 on the surface of lung epithelium were inhibited by ulinastatin. Ulinastatin also reduced the increase in pulmonary microvascular permeability. Consistent with these findings, ulinastatin ameliorated the lung edema and pulmonary oxygenation in burn-injured rats. CONCLUSIONS: These results indicate that the inhibitory effects of ulinastatin on inflammatory mediator production, neutrophil activation, and microvascular permeability are associated with the recovery of pulmonary functions in severe burn-induced acute lung injury and suggest that ulinastatin may serve as a potential therapeutic administration in critical burn care.

HOXA5 counteracts the function of pathological scar-derived fibroblasts by partially activating p53 signaling.

The inactivation of p53 can lead to the formation of pathological scars, including hypertrophic scars and keloids. HOXA5 has been reported to be a critical transcription factor in the p53 pathway in cancers. However, whether HOXA5 also plays a role in pathological scar progression through activating p53 signaling remains unknown. In this study, we first demonstrated that HOXA5 overexpression in hypertrophic scar-or keloids-derived fibroblasts decreased cell proliferation, migration and collagen synthesis, whereas increased cell apoptosis. Furthermore, the results of luciferase activity assays and ChIP PCR assays indicated that HOXA5 transactivated p53 by binding to the ATTA-rich core motif in the p53 promoter. HOXA5 also increased the levels of p21 and Mdm2, which are downstream targets of p53. Interestingly, silencing p53 in these pathological scar-derived fibroblasts partially attenuated HOXA5-mediated growth inhibition effect and HOXA5-induced apoptosis. In addition, 9-cis-retinoic acid augmented the expression of HOXA5 and promoted the effects of HOXA5 on pathological scar-derived fibroblasts, and these effects could be suppressed by HOXA5 knockdown. Thus, our study reveals a role of HOXA5 in mediating the cellular processes of pathological scar-derived fibroblasts by transcriptionally activating the p53 signaling pathway, and 9-cis-retinoic acid may be a potential therapy for pathological scars.

[Treatment of extensive cervicomandibular scar in children and adolescent patients with bilateral expanded scapular flaps: report of 7 consecutive cases].

PURPOSE: To explore the feasibility of applying bilateral free expanded scapular flaps to treat extensive cervicomandibular scar in children and adolescents. METHODS: This study reviewed 7 children and adolescent patients who received bilateral expanded scapular flaps to treat extensive cervicomandibular scars in the Pediatric Plastic Surgery Ward from August 2018 to December 2020. The scars in all patients involved neck, mandible, and anterior chest. The cervical scars involved the anterior neck and one or both sides of the lateral neck, and there were varying degrees of cervical dysfunction and mandibular dysplasia. The operation was completed into two stages. In the first stage, the expanded circumflex scapular artery perforator flaps were designed on both sides of the back and soft tissue expanders were implanted. The expansion process lasted for 6-14 months. In the second stage, the scar tissue was removed and contracture was released, and the expanded flaps were harvested. The cervical wound was repaired with free flap transplantation by anastomosing the facial artery and vein with the circumflex scapular artery and vein. The donor sites were closed directly. RESULTS: In this series of 7 patients, one patient had poorly healed incision after the expander was implanted. One expanded flap ruptured before the second-stage surgery, which was successfully treated by secondary surgery. One patient had expansion problem due to the blockage of the internally placed injection bottle, which was treated by placing the injection bottle externally. One patient developed a small area of ischemic necrosis at the distal end of the flap after transplantation, which was treated conservatively with dressing change. The postoperative follow-up was 6 months to 2 years. The cervico-mandibular angle restored to normal range, the cervical extension, flexion, and rotation were significantly improved. Two patients underwent flap thinning and scar releasing. CONCLUSIONS: The route of the circumflex scapular artery is constant. Bilateral expanded scapular flap transplantation can be used to repair extensive cervicomandibular scar in children and adolescent patients. The flap donor site is concealed and secondary damage is minimal.

HSPA1A Protects Cells from Thermal Stress by Impeding ESCRT-0-Mediated Autophagic Flux in Epidermal Thermoresistance.

Thermoresistance is a physiological phenomenon relevant to noninvasive laser treatments for skin esthetics and tumor removal, although the underlying mechanism remains elusive. We hypothesized that HSPA1A may regulate autophagy by reducing ESCRT-0 and/or STAM2 levels, which could lead to thermal protection from cell death. In this study, we showed that thermoresistance was induced in mouse epidermal tissue and HaCaT cells by heating at 45 °C for 10 minutes. Moreover, HSPA1A levels were increased in thermoresistant mouse epidermis and HaCaT cells. HSPA1A was highly involved in protecting cells from thermal cytotoxicity, as evidenced by the knockdown or overexpression assays of the HSPA1A gene. In addition, ESCRT-0 and STAM2 levels were dramatically decreased in thermoresistant cells, which was mediated by HSPA1A binding to STAM2, particularly through HSPA1A amino acids 395‒509. Furthermore, the loss of ESCRT-0 and/or STAM2 in response to HSPA1A-STAM2 binding regulated autophagy by impeding autophagosome‒lysosome fusion and abolishing autophagic flux in cellular thermoresistance, significantly reducing thermal cytotoxicity and promoting cell survival. To our knowledge, it is previously unreported that HSPA1A-ESCRT-0 and/or STAM2 modulates heat-induced resistance by inhibiting autophagic flux. In summary, the results of this study demonstrate that the mechanisms of thermoresistance may have clinical relevance for noninvasive or minimally invasive thermal therapeutics.

Advances in the treatment of traumatic scars with laser, intense pulsed light, radiofrequency, and ultrasound.

Traumatic scarring is one of the most common complications after soft tissue injury caused by burns and trauma, which affects tens of millions of people worldwide every year. Traumatic scars diminish the quality of life due to disfigurement, symptoms of pain and itch, and restricted motion. The pathogenesis and pathophysiology of traumatic scar remain elusive. The management for traumatic scars is comprised of surgical and non-surgical interventions such as pressure therapy, silicone, corticosteroid, and radiotherapy, which are chosen by clinicians based on the physical examinations of scars. Recently, great progress in treating traumatic scars has been achieved by the development of novel technologies including laser, intense pulsed light (IPL), radiofrequency, and ultrasound. The aim of this review article was to summarize the advances of these technologies for traumatic scars intervention.

460nm visible light irradiation eradicates MRSA via inducing prophage activation.

A growing number of researches demonstrate that light with a wavelength between 400 and 500nm, namely blue light (BL), has exhibited antibacterial effects on methicillin-resistant Staphylococcus aureus (MRSA) and other microbes. However, there is insufficient evidence to show that BL kills MRSA inside biofilm and the mechanisms underlying the antibacterial effects remain unclear. Here we demonstrate that BL irradiation with 460nm effectively eliminated both planktonic and biofilm MRSA in a dose-dependent manner by utilizing a planktonic MRSA or MRSA biofilm model. Furthermore, using a animal model of skin wound infections with MRSA, we found that 460nm BL showed a therapeutic effect on MRSA infected wounds in mice with significant killing of MRSA, better survival and wound healing. Moreover, RNA sequencing was used to analyze differential gene expressions in MRSA genome after BL irradiation. Our data showed that about one third of up-regulated genes were phage-related. Using phage inhibitor GS-11P, increased prophage activation in MRSA cells induced by BL irradiation was blocked and phage particles were observed. The results indicate that blue visible light irradiation with 460nm is a novel tool for eliminating both planktonic and biofilm MRSA. Prophage activation may be involved in the process. This study may provide a new perspective to understand the antibacterial mechanism by BL.

Involvements of γδT Lymphocytes in Acute and Chronic Skin Wound Repair.

Wound healing involves three stages including inflammation, proliferation, and tissue remodeling. The underlying mechanisms remain to be further elucidated. The inflammation is characterized by spatially and temporally changing patterns of various leukocyte subsets. It is regarded as the most crucial stage since the inflammatory response is instrumental to supplying various factors and cytokines that orchestrate healing events. As a subtype of T lymphocytes, γδ T cells play an important role in skin homeostasis, tumor immunosurveillance, and wound repair. However, either the dynamics of γδ T cells in healing process or the anticipated association of γδ T cells with chronic or refractory wounds were not well understood. In this study, we determine the dynamics of γδ T cells and γδ T cell-produced effectors during acute and chronic wound repair by establishing a third-degree burn model in mice skin or human skin from diabetic patients. Our data show that the involvement of γδ T cells in acute and chronic skin wound healing. The protein levels and mRNA expressions of γδ T cell-produced effectors were increased in acute healing model, whereas those effectors were decreased in chronic repair, suggesting γδ T cells are essential for wound repair. This study probes into the significant relevance of γδ T cells with effective wound repair and provides new enlightenments for the mechanisms of the formation of chronic and/or refractory wounds.

Reactive Oxygen Species Mediated Prostaglandin E2 Contributes to Acute Response of Epithelial Injury.

Reactive oxygen species (ROS) generated after tissue injury play a crucial role during wound healing through initiating acute inflammation, clarifying infection and dead tissue, and mediating various intracellular signal transduction. Prostaglandin E2 (PGE2) has been identified as one of the major factors responsible for inflammation and tissue repair. In this study, we tested our hypothesis that ROS produced by damaged human keratinocytes induces the synthesis of PGE2. In vitro epithelial wounding model was used to observe the production of ROS and secretion of PGE2 as well as the involved signal pathway. The mechanical injury caused the rapid production of ROS in in vitro cultured keratinocytes, which was significantly blocked by an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase. The increased intracellular ROS caused by mechanical injury stimulates PGE2 production in a time-dependent manner via the activation of cyclooxygenase-2 (COX-2), which was stimulated by phosphorylation of extracellular signal-regulated protein kinase (ERK). These results indicate ROS-induced ERK activation leading to the activation of COX-2 and the synthesis of PGE2 in human keratinocytes responding to mechanical injury in the acute phase.

AGEs Induced Autophagy Impairs Cutaneous Wound Healing via Stimulating Macrophage Polarization to M1 in Diabetes.

Autophagy is essential in physiological and pathological processes, however, the role of autophagy in cutaneous wound healing and the underlying molecular mechanism remain elusive. We hypothesized that autophagy plays an important role in regulating wound healing. Here, we show that enhanced autophagy negatively impacts on normal cutaneous healing process and is related to chronic wounds as demonstrated by the increased LC3 in diabetic mice skin or patients' chronic wounds. In addition, inhibition of autophagy by 3-MA restores delayed healing in C57BL/6 or db/db mice, demonstrating that autophagy is involved in regulating wound healing. Furthermore, we identify that macrophage is a major cell type underwent autophagy in wounds and increased autophagy induces macrophages polarization into M1 with elevated CD11c population and gene expressions of proinflammatory cytokines. To explore the mechanism underlying autophagy-impaired wound healing, we tested the role of IRF8, a regulator of autophagy, in autophagy-modulated macrophages polarization. IRF8 activation is up-regulating autophagy and M1 polarization of macrophages after AGEs (advanced glycation endproducts) treatment, blocking the IRF8 with shIRF8 inhibits autophagic activity and M1 polarization. In summary, this study elucidates that AGEs induces autophagy and modulates macrophage polarization to M1 via IRF8 activation in impairment of cutaneous wound healing.