Dynamic changes of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 after burn injury

Comparison of 16 Pediatric Acute Respiratory Distress Syndrome-Associated Plasma Biomarkers With Changing Lung Injury Severity

OBJECTIVES

Pediatric acute respiratory distress syndrome (PARDS) is a source of substantial morbidity and mortality in the PICU, and different plasma biomarkers have identified different PARDS and ARDS subgroups. We have a poor understanding of how these biomarkers change over time and with changing lung injuries. We sought to determine how biomarker levels change over PARDS course, whether they are correlated, and whether they are different in critically ill non-PARDS patients.

DESIGN

Two-center prospective observational study.

SETTING

Two quaternary care academic children's hospitals.

PATIENTS

Subjects under 18 years of age admitted to the PICU who were intubated and met the Second Pediatric Acute Lung Injury Consensus Conference-2 PARDS diagnostic criteria and nonintubated critically ill subjects without apparent lung disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma samples were obtained on study days 1, 3, 7, and 14. The levels of 16 biomarkers were measured using a fluorometric bead-based assay. Compared with non-PARDS subjects, on day 1 PARDS subjects had increased concentrations of tumor necrosis factor-alpha, interleukin (IL)-8, interferon-γ, IL17, granzyme B, soluble intercellular adhesion molecule-1 (sICAM1), surfactant protein D, and IL18 but reduced matrix metalloproteinase 9 (MMP-9) concentrations (all p < 0.05). Day 1 biomarker concentrations and PARDS severity were not correlated. Over PARDS course, changes in 11 of the 16 biomarkers positively correlated with changing lung injury with sICAM1 ( R = 0.69, p = 2.2 × 10 -16 ) having the strongest correlation. By Spearman rank correlation of biomarker concentrations in PARDS subjects, we identified two patterns. One had elevations of plasminogen activator inhibitor-1, MMP-9, and myeloperoxidase, and the other had higher inflammatory cytokines.

CONCLUSIONS

sICAM1 had the strongest positive correlation with worsening lung injury across all study time points suggesting that it is perhaps the most biologically relevant of the 16 analytes. There was no correlation between biomarker concentration on day 1 and day 1 PARDS severity; however, changes in most biomarkers over time positively correlated with changing lung injury. Finally, in day 1 samples, 7 of the 16 biomarkers were not significantly different between PARDS and critically ill non-PARDS subjects. These data highlight the difficulty of using plasma biomarkers to identify organ-specific pathology in critically ill patients.

Identification and Verification of Five Potential Biomarkers Related to Skin and Thermal Injury Using Weighted Gene Co-Expression Network Analysis

Background: Burn injury is a life-threatening disease that does not have ideal biomarkers. Therefore, this study first applied weighted gene co-expression network analysis (WGCNA) and differentially expressed gene (DEG) screening methods to identify pivotal genes and diagnostic biomarkers associated with the skin burn process.

Methods: After obtaining transcriptomic datasets of burn patient skin and normal skin from Gene Expression Omnibus (GEO) and performing differential analysis and functional enrichment, WGCNA was used to identify hub gene modules associated with burn skin processes in the burn patient peripheral blood sample dataset and determine the correlation between modules and clinical features. Enrichment analysis was performed to identify the functions and pathways of key module genes. Differential analysis, WGCNA, protein-protein interaction analysis, and enrichment analysis were utilized to screen for hub genes. Hub genes were validated in two other GEO datasets, tested by immunohistochemistry for hub gene expression in burn patients, and receiver operating characteristic curve analysis was performed. Finally, we constructed the specific drug activity, transcription factors, and microRNA regulatory network of the five hub genes.

Results: A total of 1,373 DEGs in GSE8056 were obtained, and the top 5 upregulated genes were S100A12, CXCL8, CXCL5, MMP3, and MMP1, whereas the top 5 downregulated genes were SCGB1D2, SCGB2A2, DCD, TSPAN8, and KRT25. DEGs were significantly enriched in the immunity, epidermal development, and skin development processes. In WGCNA, the yellow module was identified as the most closely associated module with tissue damage during the burn process, and the five hub genes (ANXA3, MCEMP1, MMP9, S100A12, and TCN1) were identified as the key genes for burn injury status, which consistently showed high expression in burn patient blood samples in the GSE37069 and GSE13902 datasets. Furthermore, we verified using immunohistochemistry that these five novel hub genes were also significantly elevated in burn patient skin. In addition, MCEMP1, MMP9, and S100A12 showed perfect diagnostic performance in the receiver operating characteristic analysis.

Conclusion: In conclusion, we analyzed the changes in genetic processes in the skin during burns and used them to identify five potential novel diagnostic markers in blood samples from burn patients, which are important for burn patient diagnosis. In particular, MCEMP1, MMP9, and S100A12 are three key blood biomarkers that can be used to identify skin damage in burn patients.

Clinical significance of serum matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 in the first phase of burn trauma evolution

No prospective study has specifically examined the serum levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the early shock phase of burn-injured patients. Thus, we aimed to detect early changes, activity dynamics, and the predictive value of MMP-9, TIMP-1, and the MMP-9/TIMP-1 ratio to better understand the early repair mechanisms for the development of future therapies for patients with thermal burns. Twenty-five patients with a total body surface area (TBSA) affected by burn <25%, and 30 healthy subjects were enrolled in the study. Serum levels of MMP-9 and TIMP-1 were determined by the ELISA method. Our results showed that MMP-9 concentrations increased immediately after injury and remained on a plateau. In contrast, TIMP-1 showed an upward trend throughout the 7-day study period, and the time course of the MMP-9/TIMP-1 ratio followed the inverse dynamics of TIMP-1. Analysis of the areas under the receiver operating characteristic (ROC) curves (AUC) showed that patients with burn wounds tended to have a MMP-9 value higher than 421.5 ng/ml (AUC=0.979), TIMP-1 value higher than 231.6 ng/ml (AUC=0.908), and MMP-9/TIMP-1 ratio higher than 2.31 (AUC=0.959) (P<0.001). Our findings suggest that although the variations in the two biomarkers were different regarding the time of the initial insult, their ratio is a specific and sensitive indicator of burn evolutivity in patients with a TBSA affected by a burn <25%.

Role and dynamics of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 in burn patients

Burn injuries can trigger tissue changes that can explain the variation in the level of different biochemical markers that can be recorded both locally or systemically. Some events observed in burn wounds such as vascular hyperpermeability have been associated with the release of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) after trauma. Because it is unknown whether the serum levels of MMP-9 and TIMP-1 are a consequence of these destructions or a local response to thermal damage, we decided to follow their dynamics. Twenty-five patients (mean age 49.40±17.55 years) with a total body surface area (TBSA) affected by a thermal burn of <25% and 30 healthy subjects (mean age 49.70±8.04 years) were enrolled in the present study. Enzyme immunoassays were used to measure the serum levels of MMP-9 and TIMP-1. Our results showed that MMP-9 was increased 6.25-fold immediately after injury compared to the controls and remained on a plateau throughout the 7-day monitoring period. TIMP-1 showed an upward trend with an increase of 49.52% on the seventh day after triggering insult. The time-course of the MMP-9/TIMP-1 ratio followed the inverse dynamics of TIMP-1 starting from a ratio value measured at admission 3.82-fold higher than the one observed in the healthy volunteers and a highly statistically significant correlation between the values measured at different time-points during the monitoring period (P<0.001). The results of this retrospective study indicate that the MMP-9/TIMP-1 ratio may provide information on local changes over time, starting from the triggering insult, and may be considered as a predictive biomarker of burn evolutivity.

Role of mast cells in skin regeneration after thermal burn treated with melatonin-enriched dermal film

The development of novel local therapies for thermal burns (TB) and their pathogenetic rationale are a pressing challenge. Melatonin (MT) is an endogenous factor of hemostasis regulation with pleiotropic potential. The aim of this study was to assess some parameters of tissue regeneration, the functional state of mast cells and the levels of matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) in the experimentally induced TB treated with the original MT-enriched dermal film (DF). A second-degree burn (3.5% of the total body surface area) was modelled by exposing a patch of skin to hot water. Applications of 12 cm2 DF enriched with 5 mg/g MT were performed every day for 5 days. The following parameters were calculated: the wound area, the rate of wound epithelization, the number of MC in the wound, the intensity of degranulation, and the levels of MMP-9 and VEGF expression. Over the course of treatment, the absolute wound area shrank by 35%, its epithelization rate increased, the number of MC rose, their functional state changed, and the expression of ММР-9 and VEGF increased. A negative correlation was established between the wound area and the expression of ММР-9 and VEGF, as well as between the wound area and the degranulation coefficient. Applications of MT-enriched DF resulted in the reduction of the wound area, higher epithelization rate, an increase in the total MC count and degranulation intensity on days 5 and 10; it also led to a reduction in the total MC count and a loss in degranulation intensity on day 20 (166.87 (154.95; 178.78) un/mm2 vs. 464.84 (452.92; 476.76) un/mm2) in the group of intact animals), an increase in MMP-9 expression on day 5 (14.20 (11.30; 18.10) vs. 3.30 (2.20; 4.40) in the intact group), an increase in VEGF expression on days 5 and 10 (33.00 (30.20; 34.90) vs 25.40 (22.20; 29.30) in the intact group), and a reduction in MMP-9 expression on days 10 and 20 after thermal injury.

Angiogenesis: A Cellular Response to Traumatic Injury

ABSTRACT

The development of new vasculature plays a significant role in a number of chronic disease states, including neoplasm growth, peripheral arterial disease, and coronary artery disease, among many others. Traumatic injury and hemorrhage, however, is an immediate, often dramatic pathophysiologic insult that can also necessitate neovascularization to promote healing. Traditional understanding of angiogenesis involved resident endothelial cells branching outward from localized niches in the periphery. Additionally, there are a small number of circulating endothelial progenitor cells that participate directly in the process of neovessel formation. The bone marrow stores a relatively small number of so-called pro-angiogenic hematopoietic progenitor cells-that is, progenitor cells of a hematopoietic potential that differentiate into key structural cells and stimulate or otherwise support local cell growth/differentiation at the site of angiogenesis. Following injury, a number of cytokines and intercellular processes are activated or modulated to promote development of new vasculature. These processes initiate and maintain a robust response to vascular insult, allowing new vessels to canalize and anastomose and provide timely oxygen delivering to healing tissue. Ultimately as we better understand the key players in the process of angiogenesis we can look to develop novel techniques to promote healing following injury.

NF-κB mediates early blood-brain barrier disruption in a rat model of traumatic shock

BACKGROUND

Blood-brain barrier (BBB) disruption is associated with a large number of central nervous system and systemic disorders. The aim of the present study was to investigate the dynamic change of BBB changes during traumatic shock and resuscitation as well as the mechanisms involved.

METHODS

The experiments were performed on male Sprague-Dawley rats anesthetized with pentobarbital sodium. To produce traumatic shock, the rats were subjected to bilateral femoral traumatic fracture and blood withdrawal from the femoral artery to decrease mean arterial pressure (MAP) to 35 mm Hg. Hypovolemic status (at a MAP of 35 to 40 mm Hg) was sustained for 1 hour followed by fluid resuscitation with shed blood and 20 mL/kg of lactated Ringer's solution.

RESULTS

The rats were sacrificed at 1 hour, 2 hours, or 6 hours after fluid resuscitation. Blood-brain barrier permeability studies showed that traumatic shock significantly increased brain water contents and sodium fluorescein leakage, which was aggravated by fluid resuscitation. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses revealed that Na-K-Cl cotransporter-1 and vascular endothelial growth factor (VEGF) expression were upregulated in cortical brain tissue of traumatic shock rats, and this change was accompanied by downregulation of occludin and claudin-5. Traumatic shock also significantly increased the protein levels of NF-κB-p65 subunit. Of note, administration of NF-κB inhibitor PDTC effectively attenuated augmentation of the above changes.

CONCLUSION

Our results suggest that traumatic shock is associated with early BBB disruption, and inhibition of NF-κB may be an effective therapeutic strategy in protecting the BBB under traumatic shock conditions.

Protease levels are significantly altered in pediatric burn wounds

Burn wounds contain high levels of protease activity due to the need to remodel the damaged extracellular matrix proteins. While necessary, excessive protease activity can lead to improper wound healing and is associated with increased contraction and fibrosis. No studies to date have investigated the expression changes of all the collagenases and elastases in burn wounds. The present study compares gene expression changes and changes in collagenase and elastase activity between burn wound eschar and normal skin in a pediatric population. Deidentified pediatric tissues were used for these experiments. Burn wound tissue was excised as part of normal standard care within a week from injury; normal skin was removed during elective plastic surgery procedures. RNA-sequencing was performed and significant results were confirmed with qRT-PCR. Activity assays showed a significant increase in both collagenase and elastase activity in the burn wound tissue compared to the normal skin. Western blotting and substrate zymography of tissue homogenates evaluated the results at the protein levels. Four elastases and three collagenases were determined to be significantly upregulated in the wound tissues by both RNA-sequencing and qRT-PCR. Cathepsin V was the only protease that was significantly downregulated. All but one metalloproteinase studied was significantly upregulated. None of the serine proteases were significantly altered in the wound tissues. In conclusion, matrix metalloproteinases appear to be the most highly elevated proteases after a pediatric burn wound injury, at least within the first 3-7 days. The data warrant further investigation into the effects of MMPs on burn wound healing.

A Critical Update of the Assessment and Acute Management of Patients with Severe Burns

Significance: Burns are debilitating, life threatening, and difficult to assess and manage. Recent advances in assessment and management have occurred since a comprehensive review of the care of patients with severe burns was last published, which may influence research and clinical practice. Recent Advances: Recent advances have occurred in the understanding of burn pathophysiology, which has led to the identification of potential biomarkers of burn severity, such as protein C. There is new evidence about the potential superiority of natural colloids over crystalloids during fluid resuscitation, and new evidence about components of initial and perioperative management, including an improved understanding of pain following burns. Critical Issues: The limitations of the clinical examination highlight the need for imaging and biomarkers to assist in estimations of burn severity. Fluid resuscitation reduces mortality, although there is conjecture over the ideal method. The subsequent perioperative period is associated with significant morbidity and the evidence for preventing and treating pain, infection, and fluid overload while maximizing wound healing potential is described. Future Directions: Promising developments are ongoing in imaging technology, histopathology, biomarkers, and wound healing adjuncts such as hyperbaric oxygen therapy, topical negative pressure therapy, stem cell treatments, and skin substitutes. The greatest benefit from further research on management of patients with burns would most likely be derived from the elucidation of optimal fluid resuscitation protocols, pain management protocols, and surgical techniques from randomized controlled trials.

Matrix metalloproteinase-2 and its correlation with basal membrane components laminin-5 and collagen type IV in paediatric burn patients measured with Surface Plasmon Resonance Imaging (SPRI) biosensors

The purpose of this study was the determination of matrix metalloproteinase-2 and its correlation with basal membrane components laminin-5 and collagen type IV in the blood plasma of burn patients measured with Surface Plasmon Resonance Imaging (SPRI) biosensors.

MATERIAL AND METHODS

31 children scalded by hot water who were managed at the Department of Paediatric Surgery between 2014-2015, after primarily presenting with burns in 4-20% TBSA were included into the study (age 9 months up to 14 years, mean age 2,5+1 years). There were 10 girls and 21 boys. Venous blood samples were drawn 2-6h, and 12-16h after the thermal injury, and on the subsequent days 3, 5 and 7. The matrix metalloproteinase-2, collagen type IV and laminin-5 concentrations were assessed using Surface Plasmon Resonance Imaging by the investigators blinded to the other data.

RESULTS

The MMP-2, laminin-5 and collagen type IV concentrations in the blood plasma of patients with burns, were highest 12-16h after thermal injury, the difference was statistically significant. The MMP-2, laminin-5 and collagen type IV concentrations measured 3 days, 5 days and 7 days after the thermal injury, slowly decreased over time, and on the 7th day reached the normal range, when compared with the concentration measured in controls.

CONCLUSION

Current work is the first follow-up study regarding MMP-2 in burns. MMP-2, laminin-5 and collagen type IV levels were elevated early after burn injury in the plasma of studied patients, and were highest 12-16h after the injury. MMP-2, laminin-5 and collagen type IV levels were not proportional to the severity of the burn. We believe in the possibility that the gradual decrease of MMP-2, collagen type IV and laminin-5 concentrations could be connected with the process of healing, but to prove it, more investigation is needed in this area. The SPR imaging biosensor is a good diagnostic tool for determination of MMP-2, laminin-5 and collagen type IV in blood plasma of patients with burns.

Tissue Inhibitor of Matrix Metalloproteinases-1 Knockdown Suppresses the Proliferation of Human Adipose-Derived Stem Cells

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a multifunctional matrix metalloproteinase, and it is involved in the regulation of cell proliferation and apoptosis in various cell types. However, little is known about the effect of TIMP-1 expression on the proliferation of adipose-derived stem cells (ADSCs). Therefore, TIMP-1 expression in the ADSCs was firstly detected by western blotting, and TIMP-1 gene was knocked down by lentivirus-mediated shRNA. Cell proliferation was then evaluated by MTT assay and Ki67 staining, respectively. Cell cycle progression was determined by flow cytometry. The changes of p51, p21, cyclin E, cyclin-dependent kinase 2 (CDK2), and P-CDK2 caused by TIMP-1 knockdown were detected by western blotting. The results indicated that ADSCs highly expressed TIMP-1 protein, and the knockdown of TIMP-1 inhibited cell proliferation and arrested cell cycle progression at G₁ phase in the ADSCs possibly through the upregulation of p53, p21, and P-CDK2 protein levels and concurrent downregulation of cyclin E and CDK2 protein levels. These findings suggest that TIMP-1 works as a positive regulator of cell proliferation in ADSCs.

[FUNCTIONING PROTEASES IN THE ESOPHAGUS MUCOSA AFTER CHEMICAL BURNS]

The main result of esophagus burn is the formation of scars, that caused by excessive synthesis of collagen and changes the balance of metalloproteinases and their tissue inhibitors. It was studied the activity of proteolytic enzymes, participation of MMP (metalloproteinase) and their tissue inhibitors (TIMP) in alkali burns of the esophagus 1st and 2nd degrees. We have shown a significant increase of TIMP level in homogenate after alkali burns of the esophagus (an average of 31-56% depend on of burn degree). We observed a reduced activity of serine proteinase after 1st degree burns on 15th, 21st day 35 and 18% respectively, after burns 2nd degree on 15th, 21st day 54 and 50%. The decrease of activity MMP after 1st degree burns on 15th and 21st day 30, 19%, respectively, in conditions of chemical burns 2nd degree on 15th and 21st day 30, 37%. These data may indicate the development of scarring after burn simulation of 2nd degree. Further investigation of the MMP and TIMP in the process of wound healing can be useful in creating effective approaches to prevent formation of post scarring of the esophagus.

A comprehensive bioinformatics method to screen key genes for severe burn

Severe burn is a kind of traumatic injury, which can lead to serious financial burden, high morbidity and mortality following inflammatory response and complications. Microarray analysis has emerged as a popular tool for generating gene expression data and revealing the complex gene expression patterns. The Gene Expression Omnibus (GEO) repository at the National Center for Biotechnology Information has become the leading public repository of microarray data. This study aimed to study the mechanisms of severe burn. Microarray of GSE37069 was downloaded from GEO including blood samples from 244 severe burn patients and blood samples from 35 healthy controls. The differentially expressed genes (DEGs) between blood samples from healthy controls and patients were identified by t-test in the LIMMA package of R. Their interaction relationships were searched using STRING online software and then protein-protein interaction (PPI) network was constructed by Cytoscape. Using DAVID online tool, underlying functions of the DEGs involved in the PPI network were analyzed by functional and pathway enrichment analyses. We screened 541 DEGs in blood samples from severe burns patients compared with blood samples from healthy controls. Meanwhile, DEGs including MMP9, TIMP1, GZMK, GZMA, and GZMB showed higher degrees in the PPI networks. Moreover, they may function in severe burn through interacting with others. According to functional enrichment analysis, these DEGs were mainly involved in BP categories associated with inflammatory responses. MMP9, TIMP1, HGF, GZMA, GZMB, and GZMK might play important roles in severe burns.

Matrix metalloproteinases -8 and -9 and tissue inhibitor of metalloproteinase-1 in burn patients. A prospective observational study

Introduction

Matrix metalloproteinases (MMPs) -8 and -9 are released from neutrophils in acute inflammation and may contribute to permeability changes in burn injury. In retrospective studies on sepsis, levels of MMP-8, MMP-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) differed from those of healthy controls, and TIMP-1 showed an association with outcome. Our objective was to investigate the relationship between these proteins and disease severity and outcome in burn patients.

Methods

In this prospective, observational, two-center study, we collected plasma samples from admission to day 21 post-burn, and burn blister fluid samples on admission. We compared MMP-8, -9, and TIMP-1 levels between TBSA<20% (N = 19) and TBSA>20% (N = 30) injured patients and healthy controls, and between 90-day survivors and non-survivors. MMP-8, -9, and TIMP-1 levels at 24-48 hours from injury, their maximal levels, and their time-adjusted means were compared between groups. Correlations with clinical parameters and the extent of burn were analyzed. MMP-8, -9, and TIMP-1 levels in burn blister fluids were also studied.

Results

Plasma MMP-8 and -9 were higher in patients than in healthy controls (P<0.001 and P = 0.016), but only MMP-8 differed between the TBSA<20% and TBSA>20% groups. MMP-8 and -9 were not associated with clinical severity or outcome measures. TIMP-1 differed significantly between patients and controls (P<0.001) and between TBSA<20% and TBSA>20% groups (P<0.002). TIMP-1 was associated with 90-day mortality and correlated with the extent of injury and clinical measures of disease severity. TIMP-1 may serve as a new biomarker in outcome prognostication of burn patients.