Thrombin generation in abdominal sepsis is Rho-kinase-dependent

Uncovering the role of cytoskeleton proteins in the formation of neutrophil extracellular traps

Neutrophils are a type of lymphocyte involved in innate immune defense. In response to specific stimuli, these phagocytic cells undergo a unique form of cell death, NETosis, during which they release neutrophil extracellular traps (NETs) composed of modified chromatin structures decorated with cytoplasmic and granular proteins. Multiple proteins and pathways have been implicated in the formation of NETs. The cytoskeleton, an interconnected network of filamentous polymers and regulatory proteins, plays a crucial role in resisting deformation, transporting intracellular cargo, and changing shape during movement of eukaryotic cells. It may also have evolved to defend eukaryotic organisms against infection. Recent research focuses on understanding the mechanisms underlying NETs formation and how cytoskeletal networks contribute to this process, by identifying enzymes that trigger NETosis or interact with NETs and influence cellular behavior through cytoskeletal dynamics. An enhanced understanding of the complex relationship between the cytoskeleton and NET formation will provide a framework for future research and the development of targeted therapeutic strategies, and supports the notion that the long-lived cytoskeleton structures may have a lasting impact on this area of research.

Establishment and validation of a logistic regression model for prediction of septic shock severity in children

Background

Septic shock is the most severe complication of sepsis, and is a major cause of childhood mortality, constituting a heavy public health burden.

Methods

We analyzed the gene expression profiles of septic shock and control samples from the Gene Expression Omnibus (GEO). Four differentially expressed genes (DEGs) from survivor and control groups, non-survivor and control groups, and survivor and non-survivor groups were selected. We used data about these genes to establish a logistic regression model for predicting the survival of septic shock patients.

Results

Leave-one-out cross validation and receiver operating characteristic (ROC) analysis indicated that this model had good accuracy. Differential expression and Gene Set Enrichment Analysis (GSEA) between septic shock patients stratified by prediction score indicated that the systemic lupus erythematosus pathway was activated, while the limonene and pinene degradation pathways were inactivated in the high score group.

Conclusions

Our study provides a novel approach for the prediction of the severity of pathology in septic shock patients, which are significant for personalized treatment as well as prognostic assessment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-021-00206-9.

Thrombin generation is increased in patients with Clostridium difficile colitis - a pilot study

Background: There are only limited data in the literature on the thrombotic risk of patients with Clostridium difficile (CD) colitis, although this disease is widespread throughout the world. Objective: The aim of this study was to explore thrombin generation in these patients - the best way to evaluate their coagulation. Methods: A prospective observational study was conducted during 15 months on hospitalized patients with CD colitis. Thrombin generation was performed in platelet-poor plasma using a Ceveron^® alpha analyzer and was compared with a group of volunteer control subjects. Results: Thirty-three patients and 51 control subjects were enrolled in the study. Two biomarkers - mean velocity index and peak thrombin - were significantly higher in patient group, compared to the control subjects (p = 0.010, respectively, p = 0.0395). This pattern of thrombin generation suggests that patients with CD colitis without septic shock have a potential thrombotic risk. The mean velocity index significantly correlated with the estimated related risk of death according to the Charlson age-comorbidity index. Conclusions: The higher values of thrombin generation suggest that CD colitis increases the thromboembolic risk. The pattern of thrombin generation could identify patients with particularly higher thromboembolic risk. They are potential candidates for thromboprophylaxis strategies and monitorization.

Actin dynamics in the regulation of endothelial barrier functions and neutrophil recruitment during endotoxemia and sepsis

Sepsis is a leading cause of death worldwide. Increased vascular permeability is a major hallmark of sepsis. Dynamic alterations in actin fiber formation play an important role in the regulation of endothelial barrier functions and thus vascular permeability. Endothelial integrity requires a delicate balance between the formation of cortical actin filaments that maintain endothelial cell contact stability and the formation of actin stress fibers that generate pulling forces, and thus compromise endothelial cell contact stability. Current research has revealed multiple molecular pathways that regulate actin dynamics and endothelial barrier dysfunction during sepsis. These include intracellular signaling proteins of the small GTPases family (e.g., Rap1, RhoA and Rac1) as well as the molecules that are directly acting on the actomyosin cytoskeleton such as myosin light chain kinase and Rho kinases. Another hallmark of sepsis is an excessive recruitment of neutrophils that also involves changes in the actin cytoskeleton in both endothelial cells and neutrophils. This review focuses on the available evidence about molecules that control actin dynamics and regulate endothelial barrier functions and neutrophil recruitment. We also discuss treatment strategies using pharmaceutical enzyme inhibitors to target excessive vascular permeability and leukocyte recruitment in septic patients.

Rho-kinase inhibitor treatment prevents pulmonary inflammation and coagulation in lipopolysaccharide-induced lung injury

INTRODUCTION

In the pathogenesis of sepsis-induced acute lung injury (ALI), the crosstalk between inflammation and coagulation plays a pivotal role. The aim of this study was to investigate the role of Rho kinase (ROCK) inhibitor in alleviating pulmonary inflammation and coagulation in lipopolysaccharide (LPS)-induced acute lung injury (ALI) models.

METHODS

In the in vivo study, mice were randomized to four different groups: Control, Y-27632 (Y), LPS, and LPS+Y-27632 (LPS+Y). ALI was induced by intranasally administering LPS (10μg in 50μL PBS). Y-27632 (10mg/kg body weight,) was injected intraperitoneally at 18h and 1h before LPS challenge. Mice were euthanized at 3h or 8h post LPS challenge (N=8 per group). In the in vitro study, human pulmonary microvascular endothelial cells (HPMECs) were incubated with LPS alone (1μg/mL) or in combination with 10μM Y-27632 or 50μM BAY11-7082. Cells were pretreated with the inhibitors 30min before exposure to LPS. Three hours later, cells were isolated for subsequent analysis.

RESULTS

The myeloperoxidase (MPO) activity and fibrinogen deposits in the lung tissue significantly decreased and the lung damage in ALI mouse was attenuated. Pretreatment with Y-27632 markedly reduced the LPS-induced expression of interleukins 1β and 6, and the activation of nuclear factor (NF)-κB. Furthermore, ROCK inhibitor treatment antagonized the expression of tissue factor (TF) and plasminogen activator inhibitor (PAI)-1 in lung tissue and HPMECs.

CONCLUSIONS

ROCK inhibition protects against the endotoxin-induced pulmonary inflammation and coagulation via NF-kappaB pathway modulation.

Effect of Trimeric Myricetin Rhamnoside (TMR) in Carrageenan-induced Inflammation and Caecal Ligation and Puncture-induced Lung Oxidative Stress in Mice

The Eugenia jambolana is used in folklore medicine. Leaves of E. jambolana contain flavonoids as their active constituents which possess in vitro antiinflammatory, antioxidant and the antimicrobial activity. The aim of the present study was to investigate the antiinflammatory and antioxidant effects of a flavonoid glucoside, trimeric myricetin rhamnoside (TMR) isolated from leaves of E. jambolana. TMR was studied for antiinflammatory activity in carrageenan-induced hind paw oedema and antioxidant activity in lung by caecal ligation and puncture (CLP)-induced sepsis in mice. Results of the present study indicated that TMR significantly attenuated the oedema, myeloperoxidase (MPO), cytokines and prostaglandin levels in the paw after 5 h of carrageenan injection as compared to vehicle control. It also reduced the lung MPO, lipid peroxides, and serum nitrite plus nitrate levels and increased lung reduced glutathione levels 20 h of CLP as compared to vehicle control. Thus the results of this study concluded that the TMR appears to have potential benefits in diseases that are mediated by both inflammation and oxidative stress and support the pharmacological basis of use of E. jambolana plant as traditional herbal medicine for the treatment of inflammatory diseases.