Tissue inhibitor of metalloproteinase-2 inhibits burn-induced derangements and hyperpermeability in microvascular endothelial cells

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.

Experimental models of scald burns. A scope review

Purpose:

To conduct a scope review of the experimental model described by Walker and Mason, by identifying and analyzing the details of the method.

Methods:

The authors searched Pubmed-Medline, Cochrane-Bireme and PEDro databases for articles published between January 2016 and December 2018, using the following search queries: burns, burn injuries, models animal, and animal experimentation. All articles whose authors used Walker and Mason's model - with or without changes to the method in Wistar rats - were included in this study.

Results:

The search identified 45 mentions of Walker and Mason's model; however, after reading each summary, 20 were excluded (of which 5 due to duplicity). The inconsistencies observed after the scope review were: water temperature, length of time of exposure of the experimental model's skin to water, extent of the burnt area, and the description of the thickness/depth of the injury.

Conclusions:

Reproducibility of a scientific method is the basis to prove the veracity of the observed results. Thus, it is necessary to have a greater number of publications that adopt a reproducible scientific method, for this review found inconsistencies in the description of Walker and Mason's model.

Role of Resveratrol on Indoxyl Sulfate-Induced Endothelial Hyperpermeability via Aryl Hydrocarbon Receptor (AHR)/Src-Dependent Pathway

Resveratrol (RES), a dietary polyphenol compound, has been shown to possess health benefits due to its anti-inflammatory, antioxidative, and antiatherosclerosis properties. Tryptophan metabolite-derived indoxyl sulfate (IS) is identified as one of the uremic toxins and physiological endogenous ligand/activator of aryl hydrocarbon receptor (AHR), associated with atherosclerosis in chronic kidney disease (CKD) patients. Studies have shown that a high serum level of IS causes deleterious effects on health primarily by inducing oxidative stress and endothelial dysfunction. However, the precise mechanisms are still unclear. Here, we investigated the underlying mechanism of IS effect on endothelial permeability and the role of RES on IS-induced endothelial hyperpermeability via the AHR/Src-dependent pathway. Bovine aorta endothelial cells (BAECs) were cultured and incubated with IS in the presence or absence of RES, and transendothelial electrical resistance (TEER) and permeability of cells were measured. Alongside, AHR, Src kinase, and Vascular Endothelial Cadherin (VE-Cadherin) activation were examined. Our data showed that IS reduced TEER of cells resulting in increased permeability. VE-Cadherin, a vital regulator of endothelial permeability, was also significantly activated in response to IS, which appeared to be associated with changes of endothelial permeability and AHR/Src kinase. Interestingly, in this setting, RES reversed the effect of IS and inhibited the increased activation of Src induced by IS-activated AHR and modulated VE-Cadherin and permeability. CH223191, an inhibitor of AHR, significantly inhibits IS-induced endothelial hyperpermeability. Further analysis with treatment of PP2, an inhibitor of Src abolishing Src activation, suggests downstream factors. All our data indicated that IS upregulated the AHR/Src kinase pathway, and increased endothelial permeability and phosphorylation of VE-Cadherin may be represented and provide new strategies for addressing protective properties of RES against Src kinase involved in AHR-mediated endothelial hyperpermeability. The findings may be crucial for managing diseases in which endothelial permeability is compromised, and the dietary polyphenols are involved.

Quetiapine protects the blood-brain barrier in traumatic brain injury

BACKGROUND

The integrity of the blood-brain barrier (BBB) is paramount in limiting vasogenic edema following traumatic brain injury (TBI). The purpose of this study was to ascertain if quetiapine, an atypical antipsychotic commonly used in trauma/critical care for delirium, protects the BBB and attenuates hyperpermeability in TBI.

METHODS

The effect of quetiapine on hyperpermeability was examined through molecular modeling, cellular models in vitro and small animal models in vivo. Molecular docking was performed with AutoDock Vina to matrix metalloproteinase-9. Rat brain microvascular endothelial cells (BMECs) were pretreated with quetiapine (20 μM; 1 hour) followed by an inflammatory activator (20 μg/mL chitosan; 2 hours) and compared to controls. Immunofluorescence localization for tight junction proteins zonula occludens-1 and adherens junction protein β-catenin was performed. Human BMECs were grown as a monolayer and pretreated with quetiapine (20 μM; 1 hour) followed by chitosan (20 μg/mL; 2 hours), and transendothelial electrical resistance was measured. C57BL/6 mice (n = 5/group) underwent mild to moderate TBI (controlled cortical impactor) or sham craniotomy. The treatment group was given 10 mg/kg quetiapine intravenously 10 minutes after TBI. The difference in fluorescence intensity between intravascular and interstitium (ΔI) represented BBB hyperpermeability. A matrix metalloproteinase-9 activity assay was performed in brain tissue from animals in the experimental groups ex vivo.

RESULTS

In silico studies showed quetiapine thermodynamically favorable binding to MMP-9. Junctional localization of zonula occludens-1 and β-catenin showed retained integrity in quetiapine-treated cells as compared with the chitosan group in rat BMECs. Quetiapine attenuated monolayer permeability compared with chitosan group (p < 0.05) in human BMECs. In the animal studies, there was a significant decrease in BBB hyperpermeability and MMP-9 activity when compared between the TBI and TBI plus quetiapine groups (p < 0.05).

CONCLUSION

Quetiapine treatment may have novel anti-inflammatory properties to provide protection to the BBB by preserving tight junction integrity.

LEVEL OF EVIDENCE

level IV.

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.

A Rat Burn Injury Model for Studying Changes in Microvascular Permeability

The management of burn patients is an extremely complex and clinically challenging for patient care. Aside from the increasing reports of burn injury and morbidity and mortality directly related to it, the pathobiology of burn trauma is not clearly understood. The rat model of burn trauma described here is currently used in research laboratories to study various aspects of burn injury, including vascular dysfunctions. This model demonstrates the infliction of thermal injury in Sprague-Dawley rats using a well-established boiled water approach. We have utilized intravital microscopy to examine the microvascular hyperpermeability, the excessive leakage of proteins and fluids from the intravascular space to the extravascular space in mesenteric postcapillary venules using this model. An increase in microvascular permeability is a strong indicator of microvascular dysfunctions leading to tissue edema in burn trauma.

DT-13 Ameliorates TNF-α-Induced Vascular Endothelial Hyperpermeability via Non-Muscle Myosin IIA and the Src/PI3K/Akt Signaling Pathway

DT-13(25(R,S)-ruscogenin-1-O-[β-d-glucopyranosyl-(1→2)][β-d-xylopyranosyl-(1→3)]-β-d-fucopyranoside) has been identified as an important factor in TNF-α-induced vascular inflammation. However, the effect of DT-13 on TNF-α-induced endothelial permeability and the potential molecular mechanisms remain unclear. Hence, this study was undertaken to elucidate the protective effect of DT-13 on TNF-α-induced endothelial permeability and the underlying mechanisms in vivo and in vitro. The in vivo results showed that DT-13 could ameliorate endothelial permeability in mustard oil-induced plasma leakage in the skin and modulate ZO-1 organization. In addition, the in vitro results showed that pretreatment with DT-13 could increase the transendothelial electrical resistance value and decrease the sodium fluorescein permeability coefficient. Moreover, DT-13 altered the mRNA and protein levels of ZO-1 as determined by real-time PCR, Western blotting, and immunofluorescence analyses. DT-13 treatment decreased the phosphorylations of Src, PI3K, and Akt in TNF-α-treated human umbilical vein endothelial cells (HUVECs). Further analyses with PP2 (10 µM, inhibitor of Src) indicated that DT-13 modulated endothelial permeability in TNF-α-induced HUVECs in an Src-dependent manner. LY294002 (10 µM, PI3K inhibitor) also had the same effect on DT-13 but did not affect phosphorylation of Src. Following decreased expression of non-muscle myosin IIA (NMIIA), the effect of DT-13 on the phosphorylations of Src, PI3K, and Akt was abolished. This study provides pharmacological evidence showing that DT-13 significantly ameliorated the TNF-α-induced vascular endothelial hyperpermeability through modulation of the Src/PI3K/Akt pathway and NMIIA, which play an important role in this process.