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Cytokine Jun 2024As a versatile element for maintaining homeostasis, the chemokine system has been reported to be implicated in the pathogenesis of immune thrombocytopenia (ITP)....
As a versatile element for maintaining homeostasis, the chemokine system has been reported to be implicated in the pathogenesis of immune thrombocytopenia (ITP). However, research pertaining to chemokine receptors and related ligands in adult ITP is still limited. The states of several typical chemokine receptors and cognate ligands in the circulation were comparatively assessed through various methodologies. Multiple variable analyses of correlation matrixes were conducted to characterize the correlation signatures of various chemokine receptors or candidate ligands with platelet counts. Our data illustrated a significant decrease in relative CXCR3 expression and elevated plasma levels of CXCL4, 9-11, 13, and CCL3 chemokines in ITP patients with varied platelet counts. Flow cytometry assays revealed eminently diminished CXCR3 levels on T and B lymphocytes and increased CXCR5 on cytotoxic T cell (Tc) subsets in ITP patients with certain platelet counts. Meanwhile, circulating CX3CR1 levels were markedly higher on T cells with a concomitant increase in plasma CX3CL1 level in ITP patients, highlighting the importance of aberrant alterations of the CX3CR1-CX3CL1 axis in ITP pathogenesis. Spearman's correlation analyses revealed a strong positive association of peripheral CXCL4 mRNA level, and negative correlations of plasma CXCL4 concentration and certain chemokine receptors with platelet counts, which might serve as a potential biomarker of platelet destruction in ITP development. Overall, these results indicate that the differential expression patterns and distinct activation states of peripheral chemokine network, and the subsequent expansion of circulating CXCR5 Tc cells and CX3CR1 T cells, may be a hallmark during ITP progression, which ultimately contributes to thrombocytopenia in ITP patients.
PubMed: 38936205
DOI: 10.1016/j.cyto.2024.156684 -
Vaccine: X Aug 2024Comirnaty, Pfizer-BioNTech's polyethylene-glycol (PEG)-containing Covid-19 vaccine, can cause hypersensitivity reactions (HSRs), or rarely, life-threatening anaphylaxis...
BACKGROUND
Comirnaty, Pfizer-BioNTech's polyethylene-glycol (PEG)-containing Covid-19 vaccine, can cause hypersensitivity reactions (HSRs), or rarely, life-threatening anaphylaxis in a small fraction of immunized people. A causal role of anti-PEG antibodies (Abs) has been proposed, but causality has not yet proven in an animal model. The aim of this study was to provide such evidence using pigs immunized against PEG, which displayed very high levels of anti-PEG antibodies (Abs). We also aimed to find evidence for a role of complement activation and thromboxane A2 release in blood to explore the mechanism of anaphylaxis.
METHODS
Pigs (n = 6) were immunized with 0.1 mg/kg PEGylated liposome (Doxebo) i.v., and the rise of anti-PEG IgG and IgM were measured in serial blood samples with ELISA. After ∼2-3 weeks the animals were injected i.v. with 1/3 human dose of the PEGylated mRNA vaccine, Comirnaty, and the hemodynamic (PAP, SAP) cardiopulmonary (HR, EtCO2,), hematological (WBC, granulocyte, lymphocyte and platelet counts) parameters and blood immune mediators (anti-PEG IgM and IgG antibodies, thromboxane B2, C3a) were measured as endpoints of HSRs (anaphylaxis).
RESULTS
The level of anti-PEG IgM and IgG rose 5-10-thousand-fold in all of 6 pigs immunized with Doxebo by day 6, after which time all animals developed anaphylactic shock to i.v. injection of 1/3 human dose of Comirnaty. The reaction, starting within 1 min involved maximal pulmonary hypertension and decreased systemic pulse pressure amplitude, tachycardia, granulo- and thrombocytopenia, and skin reactions (flushing or rash). These physiological changes or their absence were paralleled by C3a and TXB2 rises in blood.
CONCLUSIONS
Consistent with previous studies, these data show a causal role of anti-PEG Abs in the anaphylaxis to Comirnaty, which involves complement activation, and, hence, it represents C activation-related pseudo-anaphylaxis. The setup provides the first large-animal model for mRNA-vaccine-induced anaphylaxis in humans.
PubMed: 38933697
DOI: 10.1016/j.jvacx.2024.100497 -
Pharmaceuticals (Basel, Switzerland) May 2024Tocotrienols exhibit antioxidant and anti-inflammatory activities. RhoA, a small GTPase protein, plays a crucial role in regulating contractility in airway smooth muscle...
BACKGROUND
Tocotrienols exhibit antioxidant and anti-inflammatory activities. RhoA, a small GTPase protein, plays a crucial role in regulating contractility in airway smooth muscle (ASM). Previous studies have demonstrated that γ-tocotrienols reduce ASM proliferation and migration by inhibiting the activation of RhoA. In this present study, we investigate the effect of another vitamin E isoform, β-tocotrienols, on human ASM cell proliferation and migration stimulated by platelet-derived growth factor-BB (PDGF-BB).
METHODS
Human ASM cells were pre-treated with β-tocotrienol prior to being stimulated with PDGF-BB to induce ASM cell proliferation and migration. The proliferation and migration of PDGF-BB-induced human ASM cells were assessed using colorimetric and transwell migration assays. The intracellular ROS assay kit was employed to quantify reactive oxygen species (ROS) in human ASM cells. Additionally, we explored the effect of β-tocotrienols on the signaling pathways involved in PDGF-BB-induced ASM proliferation and migration.
RESULTS
β-tocotrienol inhibited PDGF-BB-induced ASM cell proliferation and migration by reducing RhoA activation and ROS production. However, in this present study, β-tocotrienol did not affect the signaling pathways associated with cyclin D1, phosphorylated Akt1, and ERK1/2.
CONCLUSIONS
In conclusion, the inhibition of RhoA activation and ROS production by β-tocotrienol, resulting in the reduction in human ASM proliferation and migration, suggests its potential as a treatment for asthma airway remodeling.
PubMed: 38931379
DOI: 10.3390/ph17060712 -
International Journal of Molecular... Jun 2024Integrin αβ mediates platelet aggregation by binding the Arginyl-Glycyl-Aspartic acid (RGD) sequence of fibrinogen. RGD binding occurs at a site topographically...
Integrin αβ mediates platelet aggregation by binding the Arginyl-Glycyl-Aspartic acid (RGD) sequence of fibrinogen. RGD binding occurs at a site topographically proximal to the α and β subunits, promoting the conformational activation of the receptor from bent to extended states. While several experimental approaches have characterized RGD binding to αβ integrin, applying computational methods has been significantly more challenging due to limited sampling and the need for a priori information regarding the interactions between the RGD peptide and integrin. In this study, we employed all-atom simulations using funnel metadynamics (FM) to evaluate the interactions of an RGD peptide with the α and β subunits of integrin. FM incorporates an external history-dependent potential on selected degrees of freedom while applying a funnel-shaped restraint potential to limit RGD exploration of the unbound state. Furthermore, it does not require a priori information about the interactions, enhancing the sampling at a low computational cost. Our FM simulations reveal significant molecular changes in the β subunit of integrin upon RGD binding and provide a free-energy landscape with a low-energy binding mode surrounded by higher-energy prebinding states. The strong agreement between previous experimental and computational data and our results highlights the reliability of FM as a method for studying dynamic interactions of complex systems such as integrin.
Topics: Oligopeptides; Platelet Glycoprotein GPIIb-IIIa Complex; Protein Binding; Humans; Molecular Dynamics Simulation; Blood Platelets; Binding Sites; Integrin beta3
PubMed: 38928286
DOI: 10.3390/ijms25126580 -
International Journal of Molecular... Jun 2024Platelets have a fundamental role in mediating hemostasis and thrombosis. However, more recently, a new idea is making headway, highlighting the importance of platelets... (Review)
Review
Platelets have a fundamental role in mediating hemostasis and thrombosis. However, more recently, a new idea is making headway, highlighting the importance of platelets as significant actors in modulating immune and inflammatory responses. In particular, platelets have an important role in the development of vascular amyloid-b-peptide(ab) deposits, known to play a relevant role in Alzheimer's disease (AD) through accumulation and deposition within the frontal cortex and hippocampus in the brain. The involvement of platelets in the pathogenesis of AD opens up the highly attractive possibility of applying antiplatelet therapy for the treatment and/or prevention of AD, but conclusive results are scarce. Even less is known about the potential role of platelets in mild cognitive impairment (MCI). The aim to this brief review is to summarize current knowledge on this topic and to introduce the new perspectives on the possible role of platelet activation as therapeutic target both in AD and MCI.
Topics: Humans; Blood Platelets; Alzheimer Disease; Platelet Activation; Neurodegenerative Diseases; Cognitive Dysfunction; Animals; Amyloid beta-Peptides; Platelet Aggregation Inhibitors
PubMed: 38927999
DOI: 10.3390/ijms25126292 -
Genes Jun 2024Lipedema and lymphedema are physically similar yet distinct diseases that are commonly misdiagnosed. We previously reported that lipedema and lymphedema are associated...
Lipedema and lymphedema are physically similar yet distinct diseases that are commonly misdiagnosed. We previously reported that lipedema and lymphedema are associated with increased risk for venous thromboembolism (VTE). The underlying etiology of the prothrombotic profile observed in lipedema and lymphedema is unclear, but may be related to alterations in platelets. Our objective was to analyze the platelet transcriptome to identify biological pathways that may provide insight into platelet activation and thrombosis. The platelet transcriptome was evaluated in patients with lymphedema and lipedema, then compared to control subjects with obesity. Patients with lipedema were found to have a divergent transcriptome from patients with lymphedema. The platelet transcriptome and impacted biological pathways in lipedema were surprisingly similar to weight-matched comparators, yet different when compared to overweight individuals with a lower body mass index (BMI). Differences in the platelet transcriptome for patients with lipedema and lymphedema were found in biological pathways required for protein synthesis and degradation, as well as metabolism. Key differences in the platelet transcriptome for patients with lipedema compared to BMI-matched subjects involved metabolism and glycosaminoglycan processing. These inherent differences in the platelet transcriptome warrant further investigation, and may contribute to the increased risk of thrombosis in patients with lipedema and lymphedema.
Topics: Humans; Lymphedema; Lipedema; Female; Transcriptome; Middle Aged; Blood Platelets; Male; Adult; Body Mass Index; Platelet Activation; Obesity; Case-Control Studies
PubMed: 38927673
DOI: 10.3390/genes15060737 -
Biomedicines Jun 2024In this study, a mixed porcine-human bioengineered liver (MPH-BEL) was used in a preclinical setup of extracorporeal liver support devices as a treatment for a model of...
In this study, a mixed porcine-human bioengineered liver (MPH-BEL) was used in a preclinical setup of extracorporeal liver support devices as a treatment for a model of post-resection liver failure (PRLF). The potential for human clinical application is further illustrated by comparing the functional capacity of MPH-BEL grafts as assessed using this porcine PRLF model with fully human (FH-BEL) grafts which were perfused and assessed in vitro. BEL grafts were produced by reseeding liver scaffolds with HUVEC and primary porcine hepatocytes (MPH-BEL) or primary human hepatocytes (FH-BEL). PRLF was induced by performing an 85% liver resection in domestic white pigs and randomized into the following three groups 24 h after resection: standard medical therapy (SMT) alone, SMT + extracorporeal circuit (ECC), and SMT + MPH-BEL. The detoxification and metabolic functions of the MPH-BEL grafts were compared to FH-BEL grafts which were perfused in vitro. During the 24 h treatment interval, INR values normalized within 18 h in the MPH-BEL therapy group and urea synthesis increased as compared to the SMT and SMT + ECC control groups. The MPH-BEL treatment was associated with more rapid decline in hematocrit and platelet count compared to both control groups. Histological analysis demonstrated platelet sequestration in the MPH-BEL grafts, possibly related to immune activation. Significantly higher rates of ammonia clearance and metabolic function were observed in the FH-BEL grafts perfused in vitro than in the MPH-BEL grafts. The MPH-BEL treatment was associated with improved markers of liver function in PRLF. Further improvement in liver function in the BEL grafts was observed by seeding the biomatrix with human hepatocytes. Methods to reduce platelet sequestration within BEL grafts is an area of ongoing research.
PubMed: 38927479
DOI: 10.3390/biomedicines12061272 -
Biomolecules May 2024Platelets play essential roles in the formation of blood clots by clumping with coagulation factors at the site of vascular injury to stop bleeding; therefore, a...
Platelets play essential roles in the formation of blood clots by clumping with coagulation factors at the site of vascular injury to stop bleeding; therefore, a reduction in the platelet number or disorder in their function causes bleeding risk. In our research, we developed a method to assess platelet aggregation using an optical approach within a microfluidic chip's channel by evaluating the size of laser speckles. These speckles, associated with slowed blood flow in the microfluidic channel, had a baseline size of 28.54 ± 0.72 µm in whole blood. Removing platelets from the sample led to a notable decrease in speckle size to 27.04 ± 1.23 µm. Moreover, the addition of an ADP-containing agonist, which activates platelets, resulted in an increased speckle size of 32.89 ± 1.69 µm. This finding may provide a simple optical method via microfluidics that could be utilized to assess platelet functionality in diagnosing bleeding disorders and potentially in monitoring therapies that target platelets.
Topics: Blood Platelets; Humans; Platelet Aggregation; Platelet Function Tests; Lab-On-A-Chip Devices; Microfluidic Analytical Techniques; Microfluidics; Adenosine Diphosphate
PubMed: 38927016
DOI: 10.3390/biom14060612 -
Advanced Healthcare Materials Jun 2024Whilst blood-contacting materials are widely deployed in medicine in vascular stents, catheters and cannulas, devices fail in-situ because of thrombosis and restenosis....
Whilst blood-contacting materials are widely deployed in medicine in vascular stents, catheters and cannulas, devices fail in-situ because of thrombosis and restenosis. Furthermore, microbial attachment and biofilm formation is not an uncommon problem for medical devices. Even incremental improvements in hemocompatible materials could provide significant benefits for patients in terms of safety and patency as well as substantial cost savings.Herein, we describe a novel but simple strategy for coating a range of medical materials, that can be applied to objects of complex geometry, involving plasma-grafting of an ultra-thin hyperbranched polyglycerol coating (HPG). Plasma activation creates highly reactive surface oxygen moieties that readily react with glycidol. Irrespective of the substrate, coatings are uniform and pinhole free, comprising O-C-O repeats, with HPG chains packing in a fashion that holds reversibly binding proteins at the coating surface.In vitro assays with planar test samples show that HPG prevents platelet adhesion and activation, as well as reducing (>3log) bacterial attachment and preventing biofilm formation. Ex vivo and preclinical studies show that HPG-coated nitinol stents do not elicit thrombosis or restenosis, nor complement or neutrophil activation. Subcutaneous implantation of HPG coated disks under the skin of mice showed no evidence of toxicity nor inflammation. This article is protected by copyright. All rights reserved.
PubMed: 38924692
DOI: 10.1002/adhm.202401545 -
Advanced Healthcare Materials Jun 2024Blood-contacting medical devices routinely fail from the cascading effects of biofouling towards infection and thrombosis. Nitric oxide (NO) is an integral part of...
Blood-contacting medical devices routinely fail from the cascading effects of biofouling towards infection and thrombosis. Nitric oxide (NO) is an integral part of endothelial homeostasis, maintaining platelet quiescence and facilitating oxidative/nitrosative stress against pathogens. Recently, it has been shown that the surface evolution of NO can mediate cell-cell interactions. However, this technique alone cannot prevent the biofouling inherent in device failure with dynamic blood-contacting applications. In this work, we propose an endothelium-mimicking surface design pairing controlled NO release with an inherently antifouling polyethylene glycol interface (NO+PEG). This simple, robust, and scalable platform develops surface-localized NO availability with surface hydration, leading to a significant reduction in protein adsorption as well as bacteria/platelet adhesion. Further in vivo thrombogenicity studies show a decrease in thrombus formation on NO+PEG interfaces, with preservation of circulating platelet and white blood cell counts, maintenance of activated clotting time, and reduced coagulation cascade activation. It is anticipated that this bio-inspired surface design will enable a facile alternative to existing surface technologies to address clinical manifestations of infection and thrombosis in dynamic blood-contacting environments. This article is protected by copyright. All rights reserved.
PubMed: 38924661
DOI: 10.1002/adhm.202400492