Tissue Inhibitors of Metalloproteinase 1 (TIMP-1) and 3 (TIMP-3) as New Markers of Acute Kidney Injury After Massive Burns.

BACKGROUND Acute kidney injury (AKI) is a common and serious complication after massive burn injury. One of the postulated etiologies is destruction of the extracellular matrix of nephrons, caused by a local imbalance between matrix metalloproteinases (MMPs) and specific inhibitors. The aim of this study was to analyze the dynamics of tissue inhibitors of metalloproteinases (TIMPs) during the first 5 days after massive thermal injury and the relationship with the risk of AKI. MATERIAL AND METHODS Thirty-three adults (22 men, 11 women) with severe burns were enrolled in the study. The values of TIMPs 1 to 4 were measured in blood serum and urine using the multiplex Luminex system. The associations between TIMPs and the risk of AKI were analyzed by using the generalized linear mixed models for repeated measurements. RESULTS Significant changes in serum and urine activities of TIMPs were confirmed, especially during the first 2 days after burn injury. Almost half of patients presented renal problems during the study. Significant differences between values of TIMPs in AKI and non-AKI status were also observed. However, a significant relationship between concentration of TIMPs and risk of AKI was confirmed only for urine TIMP-1 and serum TIMP-3. CONCLUSIONS The evaluation of TIMPs in the early stage after burn injury has potential benefits. The important roles of urine TIMP-1 and serum TIMP-3, as novel markers of the risk of AKI development, were confirmed. Other parameters require further analysis.

"Simmer pus and grow flesh" method promotes chronic wound healing in rats via bFGF-Wnt ß-catenin signaling pathway.

The purpose of this study was to explore the mechanism of "simmer pus and grow meat" method based on bFGF regulating WNT / ß-Catenin signaling pathway. Of 100 SPF rats, 25 were randomly selected as blank group, and 75 rats were established chronic infectious wound model and divided into blank group, model group (normal saline treatment, n = 25), experimental group (purple and white ointment treatment, n = 25), and wet burn ointment group (wet burn treatment, n = 25). The wound healing rate of rats was compared. The protein expressions of PCAN, VEGF, bFGF, ß-Catenin, GSK-3ß and C-Myc in granulation tissues were detected. On the 7th day, the wound healing rate of the model group was lower than that of the other 3 groups (P<0.05), and the wound healing rate of the positive control group was higher than that of the experimental group and the control group (P<0.05). The expressions of bFGF, GSK-3ß and C-MyC in model group were higher than those in control group (P<0.05). The ß-catenin protein expression in the model group was lower than that in the control group (P<0.05), and the ß-catenin protein expression in the experimental group and the positive control group was higher than that in the model group (P<0.05). The expressions of PCAN and VEGF in model group were lower than those in model group (P<0.05). We found that Zibai ointment promotes chronic wound healing by modulating the bFGF/Wnt/ß-Catenin signaling pathway.

Citrus pectin protects mice from burn injury by modulating intestinal microbiota, GLP-1 secretion and immune response.

Water-soluble rhamnogalacturonan-I enriched citrus pectin (WRP) has promising effect on antimicrobial defense. We aim to determine whether the modified acidic (A) or neutral (B) WRP solutions can improve intestinal microbial dysbiosis in burn-injured mice. Male Balb/c mice were gavaged with WRPs at 80, 160, 320 mg/kg. Body weight daily for 21 days before exposed to thermal injury of 15 % total body surface area and mortality was monitored. Mice with 80 mg/kg WRPs were also subjected to fecal DNAs and T cell metabonomics analysis, intestinal and plasma glucagon-like peptide 1 (GLP-1) detection, plasma defensin, immunoglobin and intestinal barrier examinations at 1 and 3d postburn (p.b.). Burn-induced mortality was only improved by low dose WRP-A (P = 0.039). Both WRPs could prevent the dysbiosis of gut microbiota in burn injury by reducing the expansion of inflammation-promoting bacteria. Both WRPs suppressed ileum GLP-1 production at 1d p.b. (P = 0.002) and plasma GLP-1 levels at 3d p.b. (P = 0.013). Plasma GLP-1 level correlated closely with ileum GLP-1 production (P = 0.019) but negatively with microbiota diversity at 1d p.b. (P = 0.003). Intestinal T cell number was increased by both WRPs in jejunum at 3d p.b. However, the exaggerated splenic T cell metabolism in burn injury was reversed by both WRPs at 1d p.b. The burn-increased plasma defensin ß1 level was only reduced by WRP-B. Similarly, the intestinal barrier permeability was only rescued by WRP-B at 1d p.b. WRP-A rather than WRP-B could reduce burn-induced mortality in mice by suppressing intestinal GLP-1 secretion, restoring gut microbiota dysbiosis and improving adaptive immune response.

Higher serum prealbumin levels are associated with higher graft take and wound healing in adult burn patients: A prospective observational trial.

INTRODUCTION: Nutritional support is essential in burn care. There are few studies investigating the effect of nutrition on burn healing. The purpose of this study was to determine the relationship between perioperative serum prealbumin levels and the probability of autologous skin graft take in burned patients. MATERIALS AND METHODS: A prospective observational study was carried out with burned adults recruited consecutively from April 2019 until September 2021. Serum prealbumin was determined perioperatively. The percentage of graft take was evaluated over the first 5 postoperative dressing changes. Time until full epithelialization (absence of wounds) was also registered. RESULTS: A total of 60 patients were recruited, mostly middle-aged people with moderate flame burns. Serum prealbumin levels and graft take had a weak-moderate, nonlinear, statistically significant correlation. They were also an independent predictor of full epithelialization on the fifth dressing change, together with burn depth. Higher perioperative serum prealbumin levels were significantly associated with a reduction in time until full epithelialization. CONCLUSIONS: Perioperative serum prealbumin levels are significantly correlated with the probability of split-thickness skin autograft take in burned patients and with a reduced time to achieve complete epithelialization. They were an independent predictor of full graft take.

Glutamine sustains energy metabolism and alleviates liver injury in burn sepsis by promoting the assembly of mitochondrial HSP60-HSP10 complex via SIRT4 dependent protein deacetylation.

Burns and burn sepsis, characterized by persistent and profound hypercatabolism, cause energy metabolism dysfunction that worsens organ injury and systemic disorders. Glutamine (Gln) is a key nutrient that remarkably replenishes energy metabolism in burn and sepsis patients, but its exact roles beyond substrate supply is unclear. In this study, we demonstrated that Gln alleviated liver injury by sustaining energy supply and restoring redox balance. Meanwhile, Gln also rescued the dysfunctional mitochondrial electron transport chain (ETC) complexes, improved ATP production, reduced oxidative stress, and protected hepatocytes from burn sepsis injury. Mechanistically, we revealed that Gln could activate SIRT4 by upregulating its protein synthesis and increasing the level of Nicotinamide adenine dinucleotide (NAD+), a co-enzyme that sustains the activity of SIRT4. This, in turn, reduced the acetylation of shock protein (HSP) 60 to facilitate the assembly of the HSP60-HSP10 complex, which maintains the activity of ETC complex II and III and thus sustain ATP generation and reduce reactive oxygen species release. Overall, our study uncovers a previously unknown pharmacological mechanism involving the regulation of HSP60-HSP10 assembly by which Gln recovers mitochondrial complex activity, sustains cellular energy metabolism and exerts a hepato-protective role in burn sepsis.

Therapeutic effect of mitochondrial transplantation on burn injury.

As mitochondrial damage or dysfunction is commonly observed following burn injuries, we investigated whether mitochondrial transplantation (MT) can result in therapeutic benefits in the treatment of burns. Human immortalized epidermal cells (HaCaT) and Kunming mice were used to establish a heat-injured cell model and a deep partial-thickness skin burn animal model, respectively. The cell model was established by exposing HaCaT cells to 45 or 50 °C for 10 min, after which cell proliferation was assayed using fluorescent double-staining and colony formation assays, cell migration was assessed using colloidal gold migration and scratch assays, and cell cycle progression and apoptosis were measured by flow cytometry. Histopathological staining, immunohistochemistry, nick-end labeling analysis, and enzyme-linked immunosorbent assays were used to evaluate the effects of MT on inflammation, tissue recovery, apoptosis, and scar growth in a mouse model. The therapeutic effects were observed in the heat-injured HaCaT cell model. MT promoted cell viability, colony formation, proliferation, and migration; decreased G1 phase; promoted cell division; and decreased apoptosis. Wound-healing promotion, anti-inflammation (decreased mast cell aggregation, down-regulated of TNF-α, IL-1ß, IL-6, and up-regulated IL-10), acceleration of proliferation recovery (up-regulated CD34 and VEGF), apoptosis reduction, and scar formation reduction (decreased collagen I/III ratio and TGF-ß1) were observed in the MT mouse model. The MT mode of action was, however, not investigated in this study. In conclusion, our data indicate that MT exerts a therapeutic effect on burn injuries both in vitro and in vivo.

Parecoxib sodium attenuates acute lung injury following burns by regulating M1/M2 macrophage polarization through the TLR4/NF-κB pathway.

High temperature-induced burn injury often leads to an excessive inflammatory cascade resulting in multiple organ dysfunction syndrome, such as acute lung injury (ALI), in addition to skin tissue damage. As a specific COX2 inhibitor, parecoxib sodium suppresses the inflammatory response during burn injury. The effect of parecoxib sodium on ALI induced by burn injury and the associated molecular mechanism still need to be investigated. The role of parecoxib sodium in burn injury-induced ALI through the TLR4/NF-κB pathway was explored in the present study. A burn-induced ALI mouse model was constructed, and M1/M2 macrophages in lung tissue and markers involved in the TLR4/NF-κB signalling pathway were evaluated in bronchoalveolar lavage fluid (BALF) and MH-S mouse alveolar macrophages in vitro. The results indicated that parecoxib sodium attenuated lung injury after burn injury, decreased iNOS and TNF-α expression, increased IL-10 expression in BALF, and regulated the CD86-and CD206-mediated polarization of M1/M2 macrophages in lung tissue along with MH-S mouse alveolar macrophages. The effect of parecoxib sodium might be reversed by a TLR4 agonist. Overall, the results suggested that parecoxib sodium can regulate the polarization of M1/M2 macrophages through the TLR4/NF-κB pathway to attenuate ALI induced by skin burns.

The effect of Wharton's jelly-derived stem cells seeded/boron-loaded acellular scaffolds on the healing of full-thickness burn wounds in the rat model.

Burn wounds are the most destructive and complicated type of skin or underlying soft tissue injury that are exacerbated by a prolonged inflammatory response. Several cell-based therapeutic systems through the culturing of potent stem cells on modified scaffolds have been developed to direct the burn healing challenges. In this context, a new regenerative platform based on boron (B) enriched-acellular sheep small intestine submucosa (AOSIS) scaffold was designed and used as a carrier for mesenchymal stem cells derived from Wharton's jelly (WJMSCs) aiming to promote the tissue healing in burn-induced rat models. hWJMSCs have been extracted from human extra-embryonic umbilical cord tissue. Thereafter, 96 third-degree burned Wistar male rats were divided into 4 groups. The animals that did not receive any treatment were considered as group A (control). Then, group B was treated just by AOSIS scaffold, group C was received cell-seeded AOSIS scaffold (hWJMSCs-AOSIS), and group D was covered by boron enriched-cell-AOSIS scaffold (B/hWJMSCs-AOSIS). Inflammatory factors, histopathological parameters, and the expression levels of epitheliogenic and angiogenic proteins were assessed on 5, 14 and 21 d post-wounding. Application of the B/hWJMSCs-AOSIS on full-thickness skin-burned wounds significantly reduced the volume of neutrophils and lymphocytes at day 21 post-burning, whilst the number of fibroblasts and blood vessels enhanced at this time. In addition, molecular and histological analysis of wounds over time further verified that the addition of boron promoted wound healing, with decreased inflammatory factors, stimulated vascularization, accelerated re-epithelialization, and enhanced expression levels of epitheliogenic genes. In addition, the boron incorporation amplified wound closure via increasing collagen deposition and fibroblast volume and activity. Therefore, this newly fabricated hWJMSCs/B-loaded scaffold can be used as a promising system to accelerate burn wound reconstruction through inflammatory regulation and angiogenesis stimulation.

The direct binding of bioactive peptide Andersonin-W1 to TLR4 expedites the healing of diabetic skin wounds.

BACKGROUND: Chronic nonhealing wounds remain a considerable challenge in clinical treatment due to excessive inflammation and impeded reepithelialization and angiogenesis. Therefore, the discovery of novel prohealing agents for chronic skin wounds are urgent and important. Amphibian-derived prohealing peptides, especially immunomodulatory peptides, provide a promising strategy for the treatment of chronic skin trauma. However, the mechanism of immunomodulatory peptides accelerating the skin wound healing remains poorly understood. METHODS: The prohealing ability of peptide Andersonin-W1 (AW1) was assessed by cell scratch, cell proliferation, transwell, and tube formation. Next, full-thickness, deep second-degree burns and diabetic full-thickness skin wounds in mice were performed to detect the therapeutic effects of AW1. Moreover, the tissue regeneration and expression of inflammatory cytokines were evaluated by hematoxylin and eosin (H&E), enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry staining. Molecular docking, colocalization, and western blotting were used to explore the mechanism of AW1 in promoting wound healing. RESULTS: We provide solid evidence to display excellent prohealing effects of AW1, identified as a short antimicrobial peptide in our previous report. At relative low concentration of nM, AW1 promoted the proliferation, migration, and scratch repair of keratinocyte, macrophage proliferation, and tube formation of HUVEC. AW1 also facilitated reepithelialization, granulation regeneration, and angiogenesis, thus significantly boosting the healing of full-thickness, deep second-degree burns and diabetic skin wounds in mice. Mechanistically, in macrophages, AW1 directly bound to Toll-like receptor 4 (TLR4) in the extracellular region and regulated the downstream nuclear factor-κB (NF-κB) signaling pathway to facilitate the inflammatory factor secretion and suppress excessive inflammation induced by lipopolysaccharide (LPS). Moreover, AW1 regulated macrophage polarization to promote the transition from the inflammatory to the proliferative phase and then facilitated reepithelialization, granulation regeneration, and angiogenesis, thus exhibiting excellent therapeutic effects on diabetic skin wounds. CONCLUSIONS: AW1 modulates inflammation and the wound healing process by the TLR4/NF-κB molecular axis, thus facilitating reepithelialization, granulation regeneration, and angiogenesis. These findings not only provided a promising multifunctional prohealing drug candidate for chronic nonhealing skin wounds but also highlighted the unique roles of "small" peptides in the elucidation of "big" human disease mechanisms.

Adenosine diphosphate ribosylation factor 6 inhibition protects burn sepsis induced lung injury through preserving vascular integrity and suppressing ASC inflammasome transmission.

BACKGROUND: Severe burns are devastating injuries with significant immune dysfunction and result in substantial mortality and morbidity due to sepsis induced organ failure. Acute lung injury is the most common type of organ injury in sepsis, however, the mechanisms of which are poorly understood and effective therapeutic measures are limited. This study is aimed to investigate the effect of a small Guanosine triphosphatase (GTPase), Adenosine diphosphate ribosylation factor 6 (ARF6), on burn sepsis induced lung injury, and discuss the possible mechanisms. METHODS: Burn sepsis was established in male C57BL/6 mice. Mice were anesthetised by intramuscular injection of ketamine and xylazine hydrochloride, then 30% TBSA full thickness burn followed by sub-eschar injection of lipopolysaccharide. Animals were treated with intraperitoneal injection of a small molecule inhibitor of ARF6: NAV-2729, or vehicle, right after the burn and sepsis stimuli were inflicted. Lung tissues were harvested for histopathological observation and the acute lung injury scores were calculated. Organ permeability, Vascular Endothelial Cadherin (VE-cadherin) expression, inflammatory cytokine levels and myeloperoxidase activity in lung tissues were detected. Rat pulmonary microvascular endothelial cells (PMVECs) were stimulated by burn sepsis serum with or without 10 µM NAV-2729. The ARF6 activation, VE-cadherin expression, inflammasome activity, adapter protein apoptosis speck-like protein containing a caspase recruiting domain (ASC) specks and cytokines secretion were determined. Student's t test was used for comparison between two groups. Multiple comparisons among groups were performed by using analysis of variance, with Tukey's test for the post hoc test. RESULTS: NAV-2729 treatment attenuated burn sepsis induced lung injury and promoted survival of burn septic mice by preserving VE-cadherin expression in endothelial cell adherent junction and limited vascular hyperpermeability in lung tissues. Moreover, inflammatory cytokine expression and inflammatory injury in lung tissues were alleviated. Mechanistically, NAV-2729 enhanced vascular integrity by inhibiting ARF6 activation and restoring VE-cadherin expression in PMVECs. In addition, NAV-2729 inhibited ARF6-dependent phagocytosis of ASC specks, thus preventing inflammation propagation mediated by cell-to-cell transmission of ASC specks. CONCLUSIONS: ARF6 inhibition preserved vascular integrity by restoring expression of VE-cadherin and suppressed the spread of inflammation by affecting phagocytosis of ASC specks, thus protected against sepsis induced lung injury and improve survival of burn septic animals. The findings of this study implied potential therapeutics by which ARF6 inhibition can protect lung function from septic induced lung injury and improve outcomes in burn sepsis.

Morphine concentrations in fatalities after palliative treatment of acute burn injury.

The evaluation of a morphine concentration in postmortem blood is routine for a forensic toxicologist. We here report three fatal cases where we found high morphine concentrations with 7.96, 4.30, and 5.82 mg/l in femoral blood that have to be estimated as unusually high. All these individuals died due to severe burn injuries and obtained morphine in the context of their palliative care in the last hours of their lives. According to the autopsy results, the cause of death in case 1 was burn disease with burns of about 90% of the body surface area (BSA), case 2 burn trauma, and case 3 burn shock. Besides morphine, propofol, fentanyl, sufentanil, midazolam, diazepam, lorazepam, cefazolin, and rocuronium were detected in femoral blood. The findings fitted well with the detailed clinical documentation. Further evidence of therapeutic concentrations of quetiapine, duloxetine, and melperone could be matched to preexisting medication of the individuals. Physiologically based pharmacokinetic modelling (PBPK) was applied, developed for the intravenous administration of morphine, to find an explanation for the high morphine concentrations in femoral blood. Quantification of morphine in body fluids and tissue was performed to calculate morphine tissue concentration ratios to the morphine concentration in femoral blood. The presented cases show that pharmacokinetic simulations can reflect decreased renal clearance and decreased hepatic metabolism in general. However, this prediction is not sufficient to explain the high morphine concentrations in femoral blood measured here. It can be assumed that burn shock in particular leads to altered pharmacokinetics, namely decreased distribution of morphine.

Stomatin promotes neutrophil degranulation and vascular leakage in the early stage after severe burn via enhancement of the intracellular binding of neutrophil primary granules to F-actin.

BACKGROUND: The pathophysiology of severe burn injuries in the early stages involves complex emergency responses, inflammatory reactions, immune system activation, and a significant increase in vascular permeability. Neutrophils, crucial innate immune cells, undergo rapid mobilization and intricate pathophysiological changes during this period. However, the dynamic alterations and detailed mechanisms governing their biological behavior remain unclear. Stomatin protein, an essential component of the cell membrane, stabilizes and regulates the membrane and participates in cell signal transduction. Additionally, it exhibits elevated expression in various inflammatory diseases. While Stomatin expression has been observed in the cell and granule membranes of neutrophils, its potential involvement in post-activation functional regulation requires further investigation. METHODS: Neutrophils were isolated from human peripheral blood, mouse peripheral blood, and mouse bone marrow using the magnetic bead separation method. Flow cytometry was used to assess neutrophil membrane surface markers, ROS levels, and phagocytic activity. The expression of the Stomatin gene and protein was examined using quantitative real-time polymerase chain reaction and western blotting methods, respectively. Furthermore, the enzyme-linked immunosorbent assay was used to evaluate the expression of neutrophil-derived inflammatory mediators (myeloperoxidase (MPO), neutrophil elastase (NE), and matrix metalloproteinase 9 (MMP9)) in the plasma. Images and videos of vascular leakage in mice were captured using in vivo laser confocal imaging technology, whereas in vitro confocal microscopy was used to study the localization and levels of the cytoskeleton, CD63, and Stomatin protein in neutrophils. RESULTS: This study made the following key findings: (1) Early after severe burn, neutrophil dysfunction is present in the peripheral blood characterized by significant bone marrow mobilization, excessive degranulation, and impaired release and chemotaxis of inflammatory mediators (MPO, NE, and MMP9). (2) After burn injury, expression of both the stomatin gene and protein in neutrophils was upregulated. (3) Knockout (KO) of the stomatin gene in mice partially inhibited neutrophil excessive degranulation, potentially achieved via reduced production of primary granules and weakened binding of primary granules to the cell skeleton protein F-actin. (4) In severely burned mice, injury led to notable early-stage vascular leakage and lung damage, whereas Stomatin gene KO significantly ameliorated lung injury and vascular leakage. CONCLUSIONS: Stomatin promotes neutrophil degranulation in the early stage of severe burn injury via increasing the production of primary granules and enhancing their binding to the cell skeleton protein F-actin in neutrophils. Consequently, this excessive degranulation results in aggravated vascular leakage and lung injury.

Respiratory Muscle Contraction Characteristics and Potential Mechanisms in Severely Burned Rats.

Postburn hypermetabolism remains an important clinical problem. During this phase, there is a significant loss of diaphragmatic proteins. Better understanding of respiratory muscle dynamics and potential mechanisms affecting respiratory muscle function is necessary for the development of effective therapeutic approaches. Male Wistar rats were subjected to 50% TBSA burns and sham injuries, and respiratory muscle function was assessed with 0, 1, 4, 7, and 14 days postinjury, including pulmonary function, blood gas analysis, transdiaphragmatic pressure, diaphragm ultrasonography, isolated diaphragm contractility, fatigue index, protein oxidative stress content, and ATP levels. Burned rats had significantly reduced inspiratory time, expiratory time, and tidal volume and significantly increased respiratory rate and minute ventilation. At the same time, the isolated diaphragm contractility, specific force during fatigue, and fatigue index were significantly decreased in the burned rats. Pdi, Pdimax, diaphragm thickness, diaphragm thickening fraction, and diaphragm excursion also decreased significantly postburn, whereas the Pdi/Pdimax ratio increased significantly. Finally, the content of protein carbonyls and lactic acid of burned rats was increased, and ATP levels of burned rats were decreased. The present study demonstrates the dynamic changes in diaphragm contractile properties postburn from both in vivo and in vitro perspectives, while cursorily exploring the possibility that protein oxidative stress and reduced ATP production may be the cause of diaphragm dysfunction. This understanding contributes to the development of methods to mitigate the extent of diaphragmatic function loss after severe burns.

Dietary supplementation with inulin improves burn-induced skeletal muscle atrophy by regulating gut microbiota disorders.

Inulin, as a prebiotic, could modulate the gut microbiota. Burn injury leads to gut microbiota disorders and skeletal muscle catabolism. Therefore, whether inulin can improve burn-induced muscle atrophy by regulating microbiota disorders remains unknown. This study aimed to clarify that inulin intake alleviates gut microbiota disorders and skeletal muscle atrophy in burned rats. Rats were divided into the sham group, burn group, prebiotic inulin intervention group, and pseudo-aseptic validation group. A 30% total body surface area (TBSA) third-degree burn wound on dorsal skin was evaluated in all groups except the sham group. Animals in the intervention group received 7 g/L inulin. Animals in the validation group received antibiotic cocktail and inulin treatment. In our study inulin intervention could significantly alleviate the burn-induced skeletal muscle mass decrease and skeletal myoblast cell apoptosis. Inulin intake increased the abundances of Firmicutes and Actinobacteria but decreased the abundance of Proteobacteria. The biosynthesis of amino acids was the most meaningful metabolic pathway distinguishing the inulin intervention group from the burn group, and further mechanistic studies have shown that inulin can promote the phosphorylation of the myogenesis-related proteins PI3K, AKT and P70S6K and activate PI3K/AKT signaling for protein synthesis. In conclusion, inulin alleviated burn induced muscle atrophy through PI3K/AKT signaling and regulated gut microbiota dysbiosis.

Characterization of Cell Type Abundance and Gene Expression Timeline from Burned Skin Bulk Transcriptomics by Deconvolution.

Currently, no timeline of cell heterogeneity in thermally injured skin has been reported. In this study, we proposed an approach to deconvoluting cell type abundance and expression from skin bulk transcriptomics with cell type signature matrix constructed by combining independent normal skin and peripheral blood scRNA-seq datasets. Using CIBERSORTx group mode deconvolution, we identified perturbed cell type fractions and cell type-specific gene expression in three stages postthermal injury. We found an increase in cell proportions and cell type-specific gene expression perturbation of neutrophils, macrophages, and endothelial cells and a decrease in CD4+ T cells, keratinocytes, melanocyte, and fibroblast cells, and cell type-specific gene expression perturbation postburn injury. Keratinocyte, fibroblast, and macrophage up regulated genes were dynamically enriched in overlapping and distinct Gene Ontology biological processes including acute phase response, leukocyte migration, metabolic, morphogenesis, and development process. Down-regulated genes were enriched in Wnt signaling, mesenchymal cell differentiation, gland and axon development, epidermal morphogenesis, and fatty acid and glucose metabolic process. We noticed an increase in the expression of CCL7, CCL2, CCL20, CCR1, CCR5, CCXL8, CXCL2, CXCL3, MMP1, MMP8, MMP3, IL24, IL6, IL1B, IL18R1, and TGFBR1 and a decrease in expression of CCL27, CCR10, CCR6, CCR8, CXCL9, IL37, IL17, IL7, IL11R, IL17R, TGFBR3, FGFR1-4, and IGFR1 in keratinocytes and/or fibroblasts. The inferred timeline of wound healing and CC and CXC genes in keratinocyte was validated on independent dataset GSE174661 of purified keratinocytes. The timeline of different cell types postburn may facilitate therapeutic timing.

Multicomponent decellularized extracellular matrix of caprine small intestine submucosa based bioactive hydrogel promoting full-thickness burn wound healing in rabbits.

Effective treatment for full-thickness burn wounds has remained challenging for clinicians. Among various strategies, extracellular gel-based dressing materials have gained attention to promote effective and rapid wound healing. These gel-based materials are porous and have antioxidant, antibacterial, hydrophilic, biodegradation, and biocompatible properties and hence can be used to alleviate burn wound healing. In concurrence with these findings, the present study evaluates thermo-responsive and self-assembled decellularized extracellular matrix (ECM) of caprine small intestine submucosa (DG-SIS) gel-based dressing material for burn wound healing. To expedite healing and efficiently tackle excessive free radicals and bioburden at the burn wound site, DG-SIS gel is fortified with antibacterial components (zinc oxide nanoparticles; ZnO) and a potent antioxidant agent (Vitamin-C;Vt-C). ZnO- and Vt-C-enriched DG-SIS (DG-SIS/ZnO/Vt-C) gels significantly increased the antioxidant and antibacterial activity of the therapeutic hydrogel. Additionally, the fabricated DG-SIS/ZnO/Vt-C bioactive gel resulted in significant full-thickness burn wound contraction (97.75 % in 14 days), a lower inflammatory effect, and enhanced angiogenesis with the highest collagen synthesis (1.22 µg/mg in 14 days) at the wound site. The outcomes from this study demonstrate a synergistic effect of ZnO/Vt-C in the bioactive gel as an effective and inexpensive therapeutic approach for full-thickness burn wound treatment.

Alleviation effects of epigallocatechin-3-gallate against acute kidney injury following severe burns.

BACKGROUND: Burn patients often face a high risk of acute kidney injury (AKI) after severe burn injuries, meanwhile epigallocatechin-3-gallate (EGCG) has been proven to be effective in alleviating organ injury. METHODS: This study used the classical burn model in rats. Thirty model rats were randomly divided into a Burn group, a Burn + placebo group, a Burn + EGCG (50 mg/kg) group, and ten non-model rats as Sham group. The urinary excretion of the rats was subsequently monitored for a period of 48 h. After 48 h of different treatments, rat serum and kidneys were taken for the further verification. The efficacy of EGCG was assessed in pathological sections, biochemical indexes, and at the molecular level. RESULTS: Pathological sections were compared between the Burn group and Burn + placebo group. The rats in the Burn + EGCG group had less kidney damage. Moreover, the EGCG group maintained significantly elevated urine volumes, biochemical indexes manifested that EGCG could reduce serum creatinine (Cr) and neutrophil gelatinase-associated lipocalin (NGAL) level and inhibit the oxidation-related enzyme malondialdehyde (MDA) level, meanwhile the superoxide dismutase (SOD) level was increased. The molecular level showed that EGCG significantly reduced the mRNA expression levels of the inflammation-related molecules interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). CONCLUSION: The research indicated that EGCG had an alleviating effect on kidney injury in severely burned rats, and its alleviating effects were related to improving kidney functions, alleviating oxidative stress, and inhibiting the expression of inflammatory factors.

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

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1ß, IL-6, TGF-ß1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1ß, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Comparison research on the therapeutic effects of botulinum toxin type A and stromal vascular fraction gel on hypertrophic scars in the rabbit ear model.

BACKGROUND AND OBJECTIVES: Botulinum toxin type A (BTA) is often used for wrinkles and muscle convulsive diseases due to its blocking of the transmission of nerve impulses. Stromal vascular fraction gel (SVF-gel) prepared from adipose tissue has novel effects on skin depression and poor texture. Both BTA and SVF-gel are proved to possess anti-scar potential. This study aimed to assess and compare their therapeutic effects on hypertrophic scars. MATERIALS AND METHODS: The rabbit ear scar model was established and treated with BTA and SVF-gel, alone or in combination. Gross evaluation using Manchester Scar Scale (MSS) was conducted immediately, 4 and 8 weeks after initial treatment. After tissue sample harvest, histological and Western blot analyses were performed. RESULTS: All the treatments alleviated scar hyperplasia in different degrees by inhibiting fibroblast activation (Ki-67, α-SMA), tissue inflammation (CD45, IL-1ß) and the transforming growth factor-ß1 (TGF-ß1)/Smad3 pathway. Despite an excellent anti-inflammatory effect, improvement of scar appearance and pathological characteristics in SVF-gel-contained groups was not as good as that in BTA-only group, which might be related to the retention of M2-type macrophages (CD163 +) and partial maintenance of TGF-ß1 expression. CONCLUSION: Our data suggest that BTA has better anti-scar efficacy than SVF-gel, and the combination of these two treatments shows no obvious combinatorial effect.

Experimental Study on the Effect of Caffeine Hydrogel on the Expression of TGF -ß1, α-SMA and Collagen in Hypertrophic Scar of Rabbit Ears.

This study evaluated the effects of topical use of caffeine hydrogel on hypertrophic scar in a rabbit ear wound model. Nine rabbits were randomly divided into three groups: control group, caffeine hydrogel group, and matrix group. Punched defects were established on each rabbit's ear which resulted in a hypertrophic scar. When the wound epithelialization and scar hyperplasia could be seen, control group did not do any treatment, while caffeine hydrogel group and matrix group were treated with caffeine hydrogel and hydrogel matrix, respectively. After 3 weeks of administration, the general morphological changes of scar were observed, and the scar tissue of rabbit ears was stained with HE and Masson. The relative expressions of TGF ß-1, α-SMA, type I collagen, and type III collagen in scar tissue were detected by Western blot. In all three groups, findings showed that caffeine hydrogel can inhibit scar growth by reducing the expression of TGF ß-1, reducing the proliferation of fibroblasts, improving collagen arrangement and reducing collagen deposition. The overall study shows efficacy and mechanism of caffeine. It concluded that caffeine could be an effective therapeutic agent for hypertrophicscars.