P-Selectin Is Critical for De Novo Pulmonary Arterial Thrombosis Following Blunt Thoracic Trauma

Decoding Pulmonary Embolism: Pathophysiology, Diagnosis, and Treatment

Pulmonary Embolism (PE) is a life-threatening condition initiated by the presence of blood clots in the pulmonary arteries, leading to severe morbidity and mortality. Underlying mechanisms involve endothelial dysfunction, including impaired blood flow regulation, a pro-thrombotic state, inflammation, heightened oxidative stress, and altered vascular remodeling. These mechanisms contribute to vascular diseases stemming from PE, such as recurrent thromboembolism, chronic thromboembolic pulmonary hypertension, post-thrombotic syndrome, right heart failure, and cardiogenic shock. Detailing key risk factors and utilizing hemodynamic stability-based categorization, the review aims for precise risk stratification by applying established diagnostic tools and scoring systems. This article explores both conventional and emerging biomarkers as potential diagnostic tools. Additionally, by synthesizing existing knowledge, it provides a comprehensive outlook of the current enhanced PE management and preventive strategies. The conclusion underscores the need for future research to improve diagnostic accuracy and therapeutic effectiveness in PE.

Incidence and influence factors of venous thromboembolism in traumatic rib fracture patient: a multicenter study

BACKGROUND

This study aimed to determine the incidence and influencing factors of venous thromboembolism (VTE) in patients with traumatic rib fractures.

METHODS

The retrospective study analyzed medical records of patients with traumatic rib fractures from 33 hospitals.

RESULTS

The overall incidence of VTE in hospitalized patients with traumatic rib fractures was 8.1%. Patients with isolated traumatic rib fractures had a significantly lower incidence of VTE (4.4%) compared to patients with rib fractures combined with other injuries (12.0%). Multivariate analysis identified the number of rib fractures as an independent risk factor for thrombosis. Surgical stabilization of isolated rib fractures involving three or more ribs was associated with a lower VTE incidence compared to conservative treatment.

CONCLUSIONS

Patients with rib fractures have a higher incidence of VTE, positively correlated with the number of rib fractures. However, the occurrence of thrombosis is relatively low in isolated rib fractures. Targeted thromboprophylaxis strategies should be implemented for these patients, and surgical stabilization of rib fractures may be beneficial in reducing the risk of VTE.

Selectins and their involvement in the pathogenesis of cardiovascular diseases

The review presents current data on the structure and functional role of cell adhesion molecules belonging to the selectin family (selectins P, L and E), and their involvement in the pathogenesis of cardiovascular diseases. On the one hand, intercellular adhesion molecules of the vascular wall endothelium, platelets and leukocytes are an important link in the processes of vasculogenesis, development and regeneration of the vascular system. On the other hand, these molecules participate in the earliest stages of endothelial dysfunction with the subsequent development of pathology. For this reason, figuring out the mechanisms of activity of this group of molecules is very important for understanding the molecular basis of the cardiovascular diseases pathogenesis. The adhesion of molecules, both between cells and between cells and a component of the extracellular matrix, is the most important stage of physiological and biochemical processes. According to present knowledge, five classes of intercellular adhesion molecules are known: integrins, cadherins, immunoglobulins (including nectins), selectins and addressins. All of them are bonded to a cytoplasmic membrane and provide the interaction of cells with each other. Some of them are transmembrane and associated with the cytoskeleton of the cell. On the cell surface, intercellular adhesion molecules can be located in clusters, forming multipoint binding sites and thereby determining the degree of avidity. One of the most significant functions of selectins is participation in the initial stage of the leukocyte adhesion cascade, which results in their binding to the endothelium, rolling and further extravasation into tissues. The first stage of this process is mediated by specific non-covalent interactions between selectins and their glycan ligands, with the glycans functioning as an interface between leukocytes or cancer cells and the endothelium. Targeting these interactions remains one of the main strategies aimed at developing new methods of treating immune, inflammatory and oncological diseases.

Using novel PF4-dependent P-selectin expression assay to diagnose heparin-induced thrombocytopaenia postliver transplantation

Heparin-induced thrombocytopaenia (HIT) is a well-known adverse event associated with the use of heparin products. HIT may be difficult to diagnose in patients following liver transplantation as patients routinely require massive transfusion support and immunosuppression. As an alternative or adjunctive to the serotonin release assay, the PF4-dependent P-selectin expression assay (PEA) may be a useful diagnostic test in the determination of HIT in this patient population. In this case, we describe a 63-year-old man who had an orthotopic liver transplant that was complicated by HIT that was diagnosed using the PEA.

Palmatine Derivatives as Potential Antiplatelet Aggregation Agents via Protein Kinase G/Vasodilator-Stimulated Phosphoprotein and Phosphatidylinositol 3-Kinase/Akt Phosphorylation

Sixty palmatine (PMT) derivatives were synthesized and evaluated for antiplatelet aggregation taking berberine as the lead, and the structure-activity relationship was first systematically described. Among them, compound 2v showed the best potency in reducing adenosine diphosphate (ADP)-induced platelet aggregation in a dose-dependent manner. It greatly suppressed ADP-induced platelet aggregation, activation, and Akt phosphorylation in vitro and ex vivo after oral administration to mice. It also effectively inhibited carrageenan-induced thrombus formation in the mouse tail and lung, as well as reduced the serum P-selectin level. Compound 2v might simultaneously bind to protein kinase G to improve vasodilator-stimulated phosphoprotein phosphorylation and bind to phosphatidylinositol 3-kinase to inhibit Akt phosphorylation, which synergically reduced platelet aggregation, thereby achieving antithrombotic efficacy. Therefore, PMT derivatives constituted a novel family of antiplatelet aggregation agents with the advantage of a good safety profile, worthy of further investigation.

Challenging Traditional Paradigms in Posttraumatic Pulmonary Thromboembolism

Importance

Pulmonary clots are seen frequently on chest computed tomography performed after trauma, but recent studies suggest that pulmonary thrombosis (PT) and pulmonary embolism (PE) after trauma are independent clinical events.

Objective

To assess whether posttraumatic PT represents a distinct clinical entity associated with the nature of the injury, different from the traditional venous thromboembolic paradigm of deep venous thrombosis (DVT) and PE.

Design, Setting, and Participants

This prospective, observational, multicenter cohort study was conducted by the Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study group. The study was conducted at 17 US level I trauma centers during a 2-year period (January 1, 2018, to December 31, 2020). Consecutive patients 18 to 40 years of age admitted for a minimum of 48 hours with at least 1 previously defined trauma-associated venous thromboembolism (VTE) risk factor were followed up until discharge or 30 days.

Exposures

Investigational imaging, prophylactic measures used, and treatment of clots.

Main Outcomes and Measures

The main outcomes of interest were the presence, timing, location, and treatment of any pulmonary clots, as well as the associated injury-related risk factors. Secondary outcomes included DVT. We regarded pulmonary clots with DVT as PE and those without DVT as de novo PT.

Results

A total of 7880 patients (mean [SD] age, 29.1 [6.4] years; 5859 [74.4%] male) were studied, 277 with DVT (3.5%), 40 with PE (0.5%), and 117 with PT (1.5%). Shock on admission was present in only 460 patients (6.2%) who had no DVT, PT, or PE but was documented in 11 (27.5%) of those with PE and 30 (25.6%) in those with PT. Risk factors independently associated with PT but not DVT or PE included shock on admission (systolic blood pressure <90 mm Hg) (odds ratio, 2.74; 95% CI, 1.72-4.39; P < .001) and major chest injury with Abbreviated Injury Score of 3 or higher (odds ratio, 1.72; 95% CI, 1.16-2.56; P = .007). Factors associated with the presence of PT on admission included major chest injury (14 patients [50.0%] with or without major chest injury with an Abbreviated Injury Score >3; P = .04) and major venous injury (23 [82.1%] without major venous injury and 5 [17.9%] with major venous injury; P = .02). No deaths were attributed to PT or PE.

Conclusions and Relevance

To our knowledge, this CLOTT study is the largest prospective investigation in the world that focuses on posttraumatic PT. The study suggests that most pulmonary clots are not embolic but rather result from inflammation, endothelial injury, and the hypercoagulable state caused by the injury itself.

Association of Pericyte Loss With Microthrombosis After Subarachnoid Hemorrhage in ApoE-Deficient Mice

Background: The occurrence of microthrombosis contributes to not only delayed cerebral ischemia (DCI), but also early brain injury (EBI) after SAH. However, the underlying mechanism is not completely investigated. In the current study, we explored the underlying mechanism of microthrombosis in EBI stage after SAH in ApoE-deficient mice.

Methods: Experimental SAH was established by endovascular perforation in apolipoprotein E (ApoE)-deficient mice and wild type (WT) mice. Neurobehavioral, molecular biological and histopathological methods were used to assess the relationship between pericytes loss, neurobehavioral performance, and microthrombosis.

Results: We found that the number of microthrombi was significantly increased and peaked 48 h after SAH in WT mice. The increased microthrombosis was related to the decreased effective microcirculation perfusion area and EBI severity. ApoE-deficient mice showed more extensive microthrombosis than that of WT mice 48 h after SAH, which was thereby associated with greater neurobehavioral deficits. Immunohistochemical staining showed that microthrombi were predominantly located in microvessels where pericytes coverage was absent. Mechanistically, ApoE deficiency caused more extensive CypA-NF-κB-MMP-9 pathway activation than that observed in WT mice, which thereby led to more degradation of N-cadherin, and subsequently more pericytes loss. Thereafter, the major adhesion molecule that promoting microthrombi formation in microvessels, P-selectin, was considerably increased in WT mice and increased to a greater extent in the ApoE-deficient mice.

Conclusion: Taken together, these data suggest that pericytes loss is associated with EBI after SAH through promoting microthrombosis. Therapies that target ApoE to reduce microthrombosis may be a promising strategy for SAH treatment.

In situ Pulmonary Artery Thrombosis: A Previously Overlooked Disease

Pulmonary thromboembolism (PTE) is the third leading cause of death in cardiovascular diseases. PTE is believed to be caused by thrombi detached from deep veins of lower extremities. The thrombi travel with systemic circulation to the lung and block pulmonary arteries, leading to sudden disruption of hemodynamics and blood gas exchange. However, this concept has recently been challenged by accumulating evidence demonstrating that de novo thrombosis may be formed in pulmonary arteries without deep venous thrombosis. On the other hand, chronic thromboembolic pulmonary hypertension (CTEPH), a subtype of pulmonary hypertension, could have different pathogenesis than traditional PTE. Therefore, this article summarized and compared the risk factors, the common and specific pathogenic mechanisms underlying PTE, in situ pulmonary artery thrombosis, and CTEPH at molecular and cellular levels, and suggested the therapeutic strategies to these diseases, aiming to facilitate understanding of pathogenesis, differential diagnosis, and precision therapeutics of the three pulmonary artery thrombotic diseases.

Research progress on biomarkers of pulmonary embolism

OBJECTIVES

To present a review on the traditional and new biomarkers of pulmonary embolism (PE).

DATA SOURCE

A systematic search has been carried out using keywords as PE, biomarker, diagnosis and risk stratification.

RESULTS

The results of this work have been structured into three parts: first, conventional biomarkers for vascular, cardiac and inflammation, including static markers and dynamic markers for measuring the time course; next, a review of new biomarkers in recent years, such as RNAs and markers obtained through proteomics and mass spectrometry; finally, use of new detection methods to directly detect the activity of existing markers, such as the determination of coagulation factor II and plasmin activities based on the proteolytic activation of an engineered zymogen.

CONCLUSIONS

This work summarized the characteristics of current traditional biomarkers for clinical diagnosis and risk stratification of PE, as well as a series of newly discovered biomarkers obtained through various clinical experimental methods.

P-selectin antibody treatment after blunt thoracic trauma prevents early pulmonary arterial thrombosis without changes in viscoelastic measurements of coagulation

INTRODUCTION

Previously, in a murine model of blunt thoracic trauma, we provided evidence of primary pulmonary thrombosis associated with increased expression of the cell adhesion molecule, P-selectin. In this study, mice are treated with P-selectin blocking antibody after injury to investigate the clinical viability of this antibody for the prevention of pulmonary thrombosis. In addition, viscoelastic testing is performed to investigate if P-selectin inhibition has a detrimental impact on normal hemostasis.

METHODS

A murine model of thoracic trauma was used. Mice were divided into sham control and experimental injury groups. Thirty minutes after trauma, mice were treated with the following: P-selectin blocking antibody, isotype control antibody, low-dose heparin, high-dose heparin, or normal saline. At 90 minutes, whole blood was collected for characterization of coagulation by viscoelastic coagulation monitor (VCM Vet; Entegrion, Durham, NC). Mean clotting time, clot formation time, clot kinetics (α angle), and maximum clot firmness were compared between each treatment group.

RESULTS

Mice that received P-selectin antibody 30 minutes after blunt thoracic trauma had four- to fivefold less (p < 0.001) arterial fibrin accumulation than those that received the isotype control. In both sham and trauma groups, compared with vehicle (normal saline) alone, no statistical difference was noted in any coagulation parameters after injection with P-selectin antibody, isotype control, or low-dose heparin. In addition, blinded histopathological evaluation yielded no difference in hemorrhage scores between injured mice treated with P-selectin blocking antibody and those treated with isotype antibody control.

CONCLUSION

This study supports the clinical use of P-selectin blocking antibody for the prevention of pulmonary thrombosis by confirming its efficacy when given after a blunt thoracic trauma. In addition, we demonstrated that the administration of P-selectin antibody does not adversely affect systemic coagulation as measured by viscoelastic testing, suggesting that P-selectin antibody can be safely given during the acute posttraumatic period.

P-Selectin-Based Dual-Model Nanoprobe Used for the Specific and Rapid Visualization of Early Detection toward Severe Acute Pancreatitis in Vivo

Identifying severe acute pancreatitis (SAP) as soon as possible is critical for achieving optimal outcomes and saving lives. In this study, a novel P-selectin-targeted, NIR fluorescent dye (Cy 5.5)-labeled dual-modal nanoprobe based on diethylenetriaminepentaacetic chelates (Gd-DTPA-Cy5.5-PsLmAb) was constructed for the bimodal imaging of SAP at the early stage. Gd-DTPA-Cy5.5-PsLmAb was prepared, and its structure was characterized by Fourier transform infrared spectroscopy, UV-vis spectroscopy, and fluorescence spectroscopy, and its stability was evaluated. Biocompatibility was evaluated by the hemolysis and cytotoxicity assays. The enzyme-linked immunosorbent assay was used to detect and evaluate the expression of P-selectin in the peripheral blood of 11 patients with acute pancreatitis (AP) and 5 healthy volunteers. The bimodal imaging ability of Gd-DTPA-Cy5.5-PsLmAb nanoprobes was evaluated via near-infrared fluorescence (NIRF) and magnetic resonance imaging (MRI) in AP animal models in vivo. Gd-DTPA-Cy5.5-PsLmAb showed low toxicity to human embryonic kidney cells (293T cells) and good blood compatibility. The P-selectin levels of humans and rats in the mild acute pancreatitis (MAP)/SAP stage were significantly higher than those in the control group and reached the highest level at the SAP stage. Furthermore, Gd-DTPA-Cy5.5-PsLmAb nanoprobes showed clear NIRF imaging of mouse pancreas at the MAP stage and SAP stage by a fluorescence signal at 6.09 × 10⁸ and 1.95 × 10⁹, respectively. Meanwhile, Gd-DTPA-Cy5.5-PsLmAb nanoprobes also successfully showed the T1-weighted MR signal of rat pancreas at the MAP stage, but Gd-DTPA seldom showed any signal increase at the MAP stage; Gd-DTPA-Cy5.5-PsLmAb and Gd-DTPA could show an increasing MR signal of rat pancreas at the SAP stage. Gd-DTPA-Cy5.5-PsLmAb proved to offer a stronger signal than Gd-DTPA.Our findings indicate that Gd-DTPA-Cy5.5-PsLmAb is an effective and specific MR/NIRF dual nanoprobe for bimodal imaging, providing a promising diagnostic approach for early SAP in clinic.