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Journal of Neurointerventional Surgery Jun 2024Flow diverting stents (FDS) have transformed the treatment of intracranial aneurysms; however, their metallic structure associated with their intra-luminal positioning...
BACKGROUND
Flow diverting stents (FDS) have transformed the treatment of intracranial aneurysms; however, their metallic structure associated with their intra-luminal positioning hamper angiographic and clinical outcomes. Therefore, there is a need to develop FDS with optimized surfaces that reduce thrombogenicity while promoting the healing process and endothelialization.
METHODS
P8RI, a peptide mimicking the CD31 protein, was previously developed and grafted onto Silk Vista (SV) FDS. P8RI-SV and bare-SV were used in vitro in a blood loop model to test their hemocompatibility using human whole blood and in vivo using the rabbit elastase model for optical coherence tomography (OCT) comparisons of neointimal formation at day 5 and day 28.
RESULTS
After blood loop incubation, P8RI-SV showed significant reduction in fibrin binding (p=0.004) and platelet adhesion (p=0.041) compared with bare-SV. Similarly, derivative markers measured in blood, thromboxane B2 (platelet activation) and Thrombin-Antithrombin III complexes (coagulation activation), were also significantly reduced in the P8RI-SV group (both p=0.002). In vivo, complete or near-complete occlusion was reached in all aneurysms (n=6) at day 28. Excellent rate of stent-coverage ratio was obtained at day 5 (89.3% (79.1%-98.7%)) comparable to the observation at day 28 (91.8% (79.1%-100%); p=0.44). These rates were significantly higher compared with bare-SV at day 5 (77.8% (58.3%-86.8%); p<0.001) and at day 28 (67.7% (52.6%-88.9%); p<0.0001).
CONCLUSION
In vitro results confirm enhanced hemocompatibility with a significant anti-thrombotic effect of the P8RI-SV. In vivo results provide evidence of rapid neo-intimal growth reaching near-complete tissue healing as early as day 5 in a rabbit model.
PubMed: 38914459
DOI: 10.1136/jnis-2024-021694 -
Seminars in Thrombosis and Hemostasis Jun 2024By integrating findings from comprehensive reviews, meta-analyses, and cutting-edge genetic studies, this article illuminates the significance of stress-induced...
By integrating findings from comprehensive reviews, meta-analyses, and cutting-edge genetic studies, this article illuminates the significance of stress-induced hypercoagulability in clinical medicine. In particular, the findings from numerous prospective cohort studies indicate that stress and hemostatic factors of a hypercoagulable state are associated with increased incident risk and poor prognosis for atherosclerotic cardiovascular disease and venous thromboembolism. Mendelian randomization studies suggest that these associations are partially causal. The review synthesizes extensive research on the link between acute and chronic stress and hypercoagulability, outlining a potential pathway from stress to thrombosis risk. Consistent with the allostatic load concept, acute stress-induced hypercoagulability, initially adaptive, can turn maladaptive under chronic stress or excessive acute stress, leading to arterial or venous thrombotic events. Individuals with predisposing factors, including atherosclerosis, thrombophilia, or immobilization, may exhibit an increased risk of thrombotic disease during stress. Contextual sociodemographic characteristics, the stress experience, and coping resources additionally modulate the extent of stress-induced hypercoagulability. Research into the neuroendocrine, cellular, and molecular bases reveals how stress influences platelet activation coagulation and fibrinolysis. The activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis, along with vagal withdrawal, and the effects of catecholamines, cortisol, and vasopressin, are the central mechanisms involved. Hemoconcentration, inflammation, endothelial dysfunction, and thrombopoiesis additionally contribute to stress-induced hypercoagulability. Further research is needed to prove a causal link between chronic stress and hypercoagulability. This includes exploring its implications for the prevention and management of thrombotic diseases in stressed individuals, with a focus on developing effective psychosocial and pharmacological interventions.
PubMed: 38914118
DOI: 10.1055/s-0044-1787660 -
P-selectin Facilitates SARS-CoV-2 Spike 1 Subunit Attachment to Vesicular Endothelium and Platelets.ACS Infectious Diseases Jun 2024SARS-CoV-2 infection starts from the association of its spike 1 (S1) subunit with sensitive cells. Vesicular endothelial cells and platelets are among the cell types...
SARS-CoV-2 infection starts from the association of its spike 1 (S1) subunit with sensitive cells. Vesicular endothelial cells and platelets are among the cell types that bind SARS-CoV-2, but the effectors that mediate viral attachment on the cell membrane have not been fully elucidated. Herein, we show that P-selectin (SELP), a biomarker for endothelial dysfunction and platelet activation, can facilitate the attachment of SARS-CoV-2 S1. Since we observe colocalization of SELP with S1 in the lung tissues of COVID-19 patients, we perform molecular biology experiments on human umbilical vein endothelial cells (HUVECs) to confirm the intermolecular interaction between SELP and S1. SELP overexpression increases S1 recruitment to HUVECs and enhances SARS-CoV-2 spike pseudovirion infection. The opposite results are determined after SELP downregulation. As S1 causes endothelial inflammatory responses in a dose-dependent manner, by activating the interleukin (IL)-17 signaling pathway, SELP-induced S1 recruitment may contribute to the development of a "cytokine storm" after viral infection. Furthermore, SELP also promotes the attachment of S1 to the platelet membrane. Employment of PSI-697, a small inhibitor of SELP, markedly decreases S1 adhesion to both HUVECs and platelets. In addition to the role of membrane SELP in facilitating S1 attachment, we also discover that soluble SELP is a prognostic factor for severe COVID-19 through a meta-analysis. In this study, we identify SELP as an adhesive site for the SARS-CoV-2 S1, thus providing a potential drug target for COVID-19 treatment.
PubMed: 38912949
DOI: 10.1021/acsinfecdis.3c00728 -
JCI Insight May 2024Identifying immune correlates of protection is a major challenge in AIDS vaccine development. Anti-Envelope antibodies have been considered critical for protection...
Identifying immune correlates of protection is a major challenge in AIDS vaccine development. Anti-Envelope antibodies have been considered critical for protection against SIV/HIV (SHIV) acquisition. Here, we evaluated the efficacy of an SHIV vaccine against SIVmac251 challenge, where the role of antibody was excluded, as there was no cross-reactivity between SIV and SHIV envelope antibodies. After 8 low-dose intrarectal challenges with SIVmac251, 12 SHIV-vaccinated animals demonstrated efficacy, compared with 6 naive controls, suggesting protection was achieved in the absence of anti-envelope antibodies. Interestingly, CD8+ T cells (and some NK cells) were not essential for preventing viral acquisition, as none of the CD8-depleted macaques were infected by SIVmac251 challenges. Initial investigation of protective innate immunity revealed that protected animals had elevated pathways related to platelet aggregation/activation and reduced pathways related to interferon and responses to virus. Moreover, higher expression of platelet factor 4 on circulating platelet-leukocyte aggregates was associated with reduced viral acquisition. Our data highlighted the importance of innate immunity, identified mechanisms, and may provide opportunities for novel HIV vaccines or therapeutic strategy development.
Topics: Animals; Simian Acquired Immunodeficiency Syndrome; Simian Immunodeficiency Virus; SAIDS Vaccines; Macaca mulatta; Immunity, Innate; CD8-Positive T-Lymphocytes; Antibodies, Viral; Male; Vaccines, Attenuated
PubMed: 38912579
DOI: 10.1172/jci.insight.175800 -
Heliyon Jun 2024Inferior vena cava filters have been shown to be effective in preventing deep vein thrombosis and its secondary complication, pulmonary embolism, thereby reducing the...
BACKGROUND AND OBJECTIVE
Inferior vena cava filters have been shown to be effective in preventing deep vein thrombosis and its secondary complication, pulmonary embolism, thereby reducing the high mortality rate. Although inferior vena cava filters have evolved, specific complications like inferior vena cava thrombosis-induced deep vein thrombosis worsening and recurrent pulmonary embolism continue to pose challenges. This study analyzes the effects of geometric parameter variations of inferior vena cava filters, which have a significant impact on the thrombus formation inside the filter, the capture, dissolution, and hemodynamic flow of thrombus, as well as the shear stress on the filter and vascular wall.
METHODS
This study used computational fluid dynamic simulations with the carreau model to investigate the impact of varying inferior vena cava filter design parameters (number of struts, strut arm length, and tilt angle) on hemodynamics.
RESULTS
Recirculation and stagnation areas due to flow velocity and pressure, along with wall shear stress values, were identified as key factors. It is important to find a balance between wall shear stress high enough to aid thrombolysis and low enough to prevent platelet activation. The results of this paper show that the risk of platelet activation and thrombus filtration may be lowest when the wall shear stress of the filter ranges from 0 to 4 [Pa], minimizing stress concentration within the filter.
CONCLUSION
16 arm struts with a length of 20 mm and a tilt angle of 0° provide the best balance between thrombus capture and minimization of hemodynamic disturbance. This configuration minimizes the size of the stagnation and recirculation zones while maintaining sufficient wall shear stress for thrombus dissolution.
PubMed: 38912484
DOI: 10.1016/j.heliyon.2024.e32667 -
TH Open : Companion Journal To... Apr 2024Agonist-induced platelet activation, with the integrin αIIbβ3 conformational change, is required for fibrinogen binding. This is considered reversible under...
Agonist-induced platelet activation, with the integrin αIIbβ3 conformational change, is required for fibrinogen binding. This is considered reversible under specific conditions, allowing a second phase of platelet aggregation. The signaling pathways that differentiate between a permanent or transient activation state of platelets are poorly elucidated. To explore platelet signaling mechanisms induced by the collagen receptor glycoprotein VI (GPVI) or by protease-activated receptors (PAR) for thrombin that regulate time-dependent αIIbβ3 activation. Platelets were activated with collagen-related peptide (CRP, stimulating GPVI), thrombin receptor-activating peptides, or thrombin (stimulating PAR1 and/or 4). Integrin αIIbβ3 activation and P-selectin expression was assessed by two-color flow cytometry. Signaling pathway inhibitors were applied before or after agonist addition. Reversibility of platelet spreading was studied by microscopy. Platelet pretreatment with pharmacological inhibitors decreased GPVI- and PAR-induced integrin αIIbβ3 activation and P-selectin expression in the target order of protein kinase C (PKC) > glycogen synthase kinase 3 > β-arrestin > phosphatidylinositol-3-kinase. Posttreatment revealed secondary αIIbβ3 inactivation (not P-selectin expression), in the same order, but this reversibility was confined to CRP and PAR1 agonist. Combined inhibition of conventional and novel PKC isoforms was most effective for integrin closure. Pre- and posttreatment with ticagrelor, blocking the P2Y adenosine diphosphate (ADP) receptor, enhanced αIIbβ3 inactivation. Spreading assays showed that PKC or P2Y inhibition provoked a partial conversion from filopodia to a more discoid platelet shape. PKC and autocrine ADP signaling contribute to persistent integrin αIIbβ3 activation in the order of PAR1/GPVI > PAR4 stimulation and hence to stabilized platelet aggregation. These findings are relevant for optimization of effective antiplatelet treatment.
PubMed: 38911141
DOI: 10.1055/s-0044-1786987 -
Journal of Scleroderma and Related... Jun 2024Systemic sclerosis is a rare disease with a high mortality rate. It is a multisystem connective tissue disease due to endothelial autoimmune activation along with tissue...
Systemic sclerosis is a rare disease with a high mortality rate. It is a multisystem connective tissue disease due to endothelial autoimmune activation along with tissue and vascular fibrosis, inducing vasculopathy, with an angiogenesis wasting. The endothelial damage provokes platelet activation and immune cell adhesion. The detachment of endothelial cells leads to the interaction of platelets and collagen present in the exposed subendothelial layer. This provokes the activation of several coagulative factors, inducing a pro-thrombotic condition by thrombin generation, which converts fibrinogen into fibrin. Moreover, thrombin has other functions, such as the induction of hyperplasia in smooth muscle cells and fibroblasts, thereby favouring fibrosis. An increased risk of venous thromboembolism has been found in systemic sclerosis, whereas pulmonary hypertension may be due to the obstruction of small pulmonary arteries. Pulmonary veno-occlusive disease may also occur. Warfarin showed inconsistent results, while the outcomes of a randomised, placebo-controlled clinical trial on apixaban versus placebo are still awaited. A new anticoagulation strategy based on anti-factor XI drugs is being developed, with the aim of achieving optimal anticoagulation along with a low risk of bleeding. The molecule types under investigation in this category include monoclonal antibodies, small molecules, natural inhibitors, antisense oligonucleotides, and aptamers. Patients with systemic sclerosis may be ideal candidates for clinical trials planned to analyse the efficacy and safety of these molecules.
PubMed: 38910594
DOI: 10.1177/23971983241256250 -
International Journal of Biological... Jun 2024Thrombosis is associated with various fatal arteriovenous syndromes including ischemic stroke, myocardial infarction, and pulmonary embolism. However, current clinical... (Review)
Review
Thrombosis is associated with various fatal arteriovenous syndromes including ischemic stroke, myocardial infarction, and pulmonary embolism. However, current clinical thrombolytic treatment strategies still have many problems in targeting and safety to meet the thrombolytic therapy needs. Understanding the molecular mechanism that underlies thrombosis is critical in developing effective thrombolytic strategies. It is well known that platelets play a central role in thrombosis and the binding of fibrinogen to activated platelets is a common pathway in the process of clot formation. Based on this, a concept of biomimetic thrombus-targeted thrombolytic strategy inspired from fibrinogen binding to activated platelets in thrombosis was proposed, which could selectively bind to activated platelets at a thrombus site, thus enabling targeted delivery and local release of thrombolytic agents for effective thrombolysis. In this review, we first summarized the main characteristics of platelets and fibrinogen, and then introduced the classical molecular mechanisms of thrombosis, including platelet adhesion, platelet activation and platelet aggregation through the interactions of activated platelets with fibrinogen. In addition, we highlighted the recent advances in biomimetic thrombus-targeted thrombolytic strategies which inspired from fibrinogen binding to activated platelets in thrombosis. The possible future directions and perspectives in this emerging area are briefly discussed.
PubMed: 38908635
DOI: 10.1016/j.ijbiomac.2024.133286 -
Journal of Ethnopharmacology Jun 2024Xuefu Zhuyu Decoction (XZD), a renowned traditional Chinese medicine prescription, is widely employed for the management of conditions characterized by qi-stagnation and...
ETHNOPHARMACOLOGICAL RELEVANCE
Xuefu Zhuyu Decoction (XZD), a renowned traditional Chinese medicine prescription, is widely employed for the management of conditions characterized by qi-stagnation and blood stasis. Although its anti-thrombotic effect on deep vein thrombosis (DVT) patients has been clinically observed, the underlying mechanism remains largely unexplored.
AIM OF THE STUDY
Our aim was to investigate the mechanisms by which XZD exerted its effect on DVT.
MATERIALS AND METHODS
The ultra performance liquid chromatography (UPLC) technique was employed to evaluate quality of XZD. To examine the effect of XZD on DVT, a DVT rat model with inferior vena cava (IVC) stenosis was established. The 4D-label-free proteomics approach was then utilized to uncover the possible mechanisms of XZD against DVT. Based on proteomics, citrullinated histone H3 (CitH3), along with serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) were observed the inhibitory activity of XZD on neutrophil activation. Subsequently, the marker of platelet activation, specifically glycoprotein IIb (CD41) and glycoprotein IIIa (CD61), were assessed along with the secretion of von Willebrand factor (vWF) to investigate the inhibitory activity of XZD on platelet activation. Finally, we explored the impact of XZD on the sirtuin 1 (SIRT1)/nuclear factor kappa-B (NF-κB) pathway, which was associated with the activation of platelets and neutrophils.
RESULTS
Eight distinct components were identified for the quality control of XZD. XZD effectively reduced thrombus weight and length in DVT rats, without affecting the coagulation function or hematological parameters in the systemic circulation. Proteomics analysis revealed that XZD alleviated DVT by inhibiting the activation of platelets and neutrophils. The protein expression of CitH3, along with serum levels of TNF-α and IL-1β, were reduced in XZD-treated DVT rats. Similarly, protein expressions of CD41 and CD61, along with the release of vWF, were markedly down-regulated in XZD-treated DVT rats. Finally, treatment with XZD resulted in an up-regulation of SIRT1 protein expression and a down-regulation of both acetylated NF-κB/p65 and phosphorylated NF-κB/p65 protein expressions in endothelium.
CONCLUSIONS
XZD alleviates DVT by inhibiting the activation of platelets and neutrophils at the injured endothelium via the regulation of SIRT1/NF-κB pathway.
PubMed: 38908490
DOI: 10.1016/j.jep.2024.118485 -
Platelets Dec 2024Receptor-induced tyrosine phosphorylation of spleen tyrosine kinase (Syk) has been studied extensively in hematopoietic cells. Metabolic mapping and high-resolution mass...
Receptor-induced tyrosine phosphorylation of spleen tyrosine kinase (Syk) has been studied extensively in hematopoietic cells. Metabolic mapping and high-resolution mass spectrometry, however, indicate that one of the most frequently detected phosphorylation sites encompassed S297 (S291 in mice) located within the linker B region of Syk. It has been reported that Protein kinase C (PKC) phosphorylates Syk S297, thus influencing Syk activity. However, conflicting studies suggest that this phosphorylation enhances as well as reduces Syk activity. To clarify the function of this site, we generated Syk S291A knock-in mice. We used platelets as a model system as they possess Glycoprotein VI (GPVI), a receptor containing an immunoreceptor tyrosine-based activation motif (ITAM) which transduces signals through Syk. Our analysis of the homozygous mice indicated that the knock-in platelets express only one isoform of Syk, while the wild-type expresses two isoforms at 69 and 66 kDa. When the GPVI receptor was activated with collagen-related peptide (CRP), we observed an increase in functional responses and phosphorylations in Syk S291A platelets. This potentiation did not occur with AYPGKF or 2-MeSADP, although they also activate PKC isoforms. Although there was potentiation of platelet functional responses, there was no difference in tail bleeding times. However, the time to occlusion in the FeCl injury model was enhanced. These data indicate that the effects of Syk S291 phosphorylation represent a significant outcome on platelet activation and signaling but also reveals its multifaceted nature demonstrated by the differential effects on physiological responses .
Topics: Animals; Syk Kinase; Blood Platelets; Mice; Signal Transduction; Phosphorylation; Immunoreceptor Tyrosine-Based Activation Motif; Gene Knock-In Techniques; Humans; Platelet Membrane Glycoproteins; Platelet Activation
PubMed: 38904212
DOI: 10.1080/09537104.2024.2369766