Elevated plasma levels of TIMP-3 are associated with a higher risk of acute respiratory distress syndrome and death following severe isolated traumatic brain injury

Serum levels of matrix metalloproteinases 1, 2, and 7, and their tissue inhibitors 1, 2, 3, and 4 in polytraumatized patients: Time trajectories, correlations, and their ability to predict mortality

There has been limited research on assessing metalloproteinases (MMPs) 1, 2, and 7, as well as their tissue inhibitors (TIMPs) 1, 2, 3, and 4 in the context of polytrauma. These proteins play crucial roles in various physiological and pathological processes and could be a reliable tool in polytrauma care. We aimed to determine their clinical relevance. We assessed 24 blunt polytrauma survivors and 12 fatalities (mean age, 44.2 years, mean ISS, 45) who were directly admitted to our Level I trauma center and spent at least one night in the intensive care unit. We measured serum levels of the selected proteins on admission (day 0) and days 1, 3, 5, 7, and 10. The serum levels of the seven proteins varied considerably among individuals, resulting in similar median trend curves for TIMP1 and TIMP4 and for MMP1, MMP2, TIMP2, and TIMP3. We also found a significant interrelationship between the MMP2, TIMP2, and TIMP3 levels at the same measurement points. Furthermore, we calculated significant cross-correlations between MMP7 and MMP1, TIMP1 and MMP7, TIMP3 and MMP1, TIMP3 and MMP2, and TIMP4 and TIMP3 and an almost significant correlation between MMP7 and TIMP1 for a two-day-lag. The autocorrelation coefficient reached statistical significance for MMP1 and TIMP3. Finally, lower TIMP1 serum levels were associated with in-hospital mortality upon admission. The causal effects and interrelationships between selected proteins might provide new insights into the interactions of MMPs and TIMPs. Identifying the underlying causes might help develop personalized therapies for patients with multiple injuries. Administering recombinant TIMP1 or increasing endogenous production could improve outcomes for those with multiple injuries. However, before justifying further investigations into basic research and clinical relevance, our findings must be validated in a multicenter study using independent cohorts to account for clinical and biological variability.

Tissue inhibitors of metalloproteinases (TIMPs) modulate platelet ADAM10 activity

Platelet-specific collagen receptor glycoprotein (GP)VI is stable on the surface of circulating platelets but undergoes ectodomain cleavage on activated platelets. Activation-dependent GPVI metalloproteolysis is primarily mediated by A Disintegrin And Metalloproteinase (ADAM) 10. Regulation of platelet ADAMs activity is not well-defined however Tissue Inhibitors of Metalloproteinases (TIMPs) may play a role. As levels of TIMPs on platelets and the control of ADAMs-mediated shedding by TIMPs has not been evaluated, we quantified the levels of TIMPs on the surface of resting and activated platelets from healthy donors by flow cytometry and multiplex ELISA. Variable levels of all TIMPs could be detected on platelets. Plasma contained significant quantities of TIMP1 and TIMP2, but only trace amounts of TIMP3 and TIMP4. Recombinant TIMP3 strongly ablated resting and activated platelet ADAM10 activity, when monitored using a quenched fluorogenic peptide substrate with ADAM10 specificity. Whilst ADAM10-specific inhibitor GI254023X or ethylenediamine tetraacetic acid (EDTA) could modulate ligand-initiated shedding of GPVI, only recombinant TIMP2 achieved a modest (~20%) inhibition. We conclude that some platelet TIMPs are able to modulate platelet ADAM10 activity but none strongly regulate ligand-dependent shedding of GPVI. Our findings provide new insights into the regulation of platelet receptor sheddase activity.

Induction of endothelial barrier dysfunction by serum factors in rats subjected to traumatic brain injury and hemorrhagic shock

Traumatic brain injury (TBI) has been associated with the development of indirect acute respiratory distress syndrome (ARDS). However, the causative relationship between TBI and lung injury remains unclear. To explore potential mechanisms linking TBI with the development of ARDS, we characterized the effects of serum factors released following TBI and hemorrhagic shock (HS) in a rat model on the pulmonary endothelial cell (EC) barrier dysfunction, a key feature of ARDS. We found that serum samples from animals exposed to both controlled cortical impact (CCI) and HS, but not from sham-operated rats induced significant barrier dysfunction in human pulmonary artery EC monolayers at 2 days post injury. Thrombin inhibitor and thrombin receptor antagonist attenuated the acute phase of the serum-induced trans-endothelial resistance (TER) decline caused by CCI-HS serum, but not in later time points. However, both the early and late phases of CCI-HS-induced EC permeability were inhibited by heparin. The barrier disruptive effects of CCI-HS serum were also prevented by serum preincubation with heparin-sepharose. Pulmonary EC treated for 3 h with serum from CCI-HS rats demonstrated a significant decline in expression of EC junctional protein, VE-Cadherin, and disassembly of peripheral EC adherens junction complexes monitored by immunostaining with VE-cadherin antibody. These results suggest that exposure to CCI-HS causes early and late-phase barrier disruptive effects in vascular endothelium. While thrombin-PAR1 signaling has been identified as a mechanism of acute EC permeability increase by CCI-HS serum, the factor(s) defining long-term EC barrier disruption in CCI-HS model remains to be determined.

Altered TIMP-3 Levels in the Cerebrospinal Fluid and Plasma of Patients with Alzheimer’s Disease

Tissue inhibitor of metalloproteinase-3 (TIMP-3) is a component of the extracellular environment and is suggested to play an indirect role in regulating Aβ production and the pathophysiology of Aβ deposition in brains. However, studies on the amount of TIMP-3 in bodily fluids of Alzheimer’s disease (AD) patients have not been conducted. Here, we investigated the relationship between fluid TIMP-3 levels and AD pathology. We first showed that the fluid levels of TIMP-3 were lower in AD dementia patients compared with in non-AD patients. ELISA results revealed that plasma levels of TIMP-3 in 65 patients with AD were significantly lower than those in 115 healthy control subjects and 71 mild cognitive impairment (MCI) subjects. Furthermore, we found that cerebrospinal fluid (CSF) level of TIMP-3 was decreased in AD compared with that in healthy control. These data suggest that fluid TIMP-3 levels negatively correlated with progress of cognitive decline. Collectively, our study suggests that alterations of fluid TIMP-3 levels might be associated with AD pathology.

Transcriptome diversity and differential expression in supporting limb laminitis

Laminitis results in impaired tissue integrity and Inflammation of the epidermal and dermal lamellae connecting the hoof capsule to the underlying distal phalanx and causes loss-of-use, poor quality of life and euthanasia in horses. Historically, studies to better understand the etiology of laminitis by documenting changes in gene expression were hampered by the paucity of gene annotation specific to hoof tissues. Next-generation sequencing enables improvements to annotation by incorporating equine- and hoof-specific transcripts. Here we characterize the hoof lamellar tissue transcriptome of naturally occurring supporting limb laminitis (SLL) using archived lamellar tissue from Thoroughbred racehorses consisting of 13 SLL hospital cases and seven age-matched control horses. This was achieved using: 1) Applied transcriptome annotation by long-read sequencing to document transcript diversity and 2) short-read RNA sequencing to document changes in gene expression correlating to the developmental and acute stages of naturally occurring SLL. 1.99Gbp of long-read transcriptome sequencing deeply documented 5067 unique loci, while short read RNA-seq under very stringent quality filters described 66 differentially expressed loci. Functional analysis of these loci revealed alterations in cell replication and growth, stress response and leukocyte recruitment and activation pathways. Differential expression of the Ezrin and TIMP3 genes suggests they may have utility as biomarkers for laminitis disease, while NR1D1 and genes relevant to the inflammasome are promising targets for novel pharmacological treatments.

Management of Biliopancreatic Limb Bleeding after Roux-en-Y Gastric Bypass: A Case Report

The Roux-en-Y gastric bypass is one of the most extensive surgical treatments for obesity. The treatment of upper gastrointestinal bleeding after Roux-en-Y gastric bypass is complex due to the difficulty of accessing the excluded gastric antrum and duodenal bulb. There is no consensus regarding the management of this complication. While various techniques have been described to access the biliopancreatic limb, double-balloon enteroscopy is the most commonly used. If double-balloon enteroscopy is unavailable, a pediatric colonoscope may be used as an alternative; however, its use in such cases has not been described. We report the case of a 50-year-old male patient who underwent gastric bypass 13 years ago and was admitted for a second episode of upper gastrointestinal bleeding. The initial approach using upper endoscopy, colonoscopy, and abdominal computed tomography angiography did not reveal the cause of gastrointestinal hemorrhage; therefore, an endoscopic study of the biliopancreatic limb was performed using a pediatric colonoscope. A Forrest Ib ulcer was found in the duodenal bulb, and endoscopic therapy was administered. The evolution was found to be satisfactory.

A systematic review of biomarkers multivariately associated with acute respiratory distress syndrome development and mortality

Background

Heterogeneity of acute respiratory distress syndrome (ARDS) could be reduced by identification of biomarker-based phenotypes. The set of ARDS biomarkers to prospectively define these phenotypes remains to be established.

Objective

To provide an overview of the biomarkers that were multivariately associated with ARDS development or mortality.

Data sources

We performed a systematic search in Embase, MEDLINE, Web of Science, Cochrane CENTRAL, and Google Scholar from inception until 6 March 2020.

Study selection

Studies assessing biomarkers for ARDS development in critically ill patients at risk for ARDS and mortality due to ARDS adjusted in multivariate analyses were included.

Data extraction and synthesis

We included 35 studies for ARDS development (10,667 patients at risk for ARDS) and 53 for ARDS mortality (15,344 patients with ARDS). These studies were too heterogeneous to be used in a meta-analysis, as time until outcome and the variables used in the multivariate analyses varied widely between studies. After qualitative inspection, high plasma levels of angiopoeitin-2 and receptor for advanced glycation end products (RAGE) were associated with an increased risk of ARDS development. None of the biomarkers (plasma angiopoeitin-2, C-reactive protein, interleukin-8, RAGE, surfactant protein D, and Von Willebrand factor) was clearly associated with mortality.

Conclusions

Biomarker data reporting and variables used in multivariate analyses differed greatly between studies. Angiopoeitin-2 and RAGE in plasma were positively associated with increased risk of ARDS development. None of the biomarkers independently predicted mortality. Therefore, we suggested to structurally investigate a combination of biomarkers and clinical parameters in order to find more homogeneous ARDS phenotypes.

PROSPERO identifier

PROSPERO, CRD42017078957