Biomedical application of TiO2NPs can cause arterial thrombotic risks through triggering procoagulant activity, activation and aggregation of platelets.

BACKGROUND: Titanium dioxide nanoparticles (TiO2NPs) are widely used in medical application. However, the relevant health risk has not been completely assessed, the potential of inducing arterial thrombosis (AT) in particular. METHODS: Alterations in platelet function and susceptibility to arterial thrombosis induced by TiO2NPs were examined using peripheral blood samples from healthy adult males and an in vivo mouse model, respectively. RESULTS: Here, using human platelets (hPLTs) freshly isolated from health volunteers, we demonstrated TiO2NP treatment triggered the procoagulant activity of hPLTs through phosphatidylserine exposure and microvesicles generation. In addition, TiO2NP treatment increased the levels of glycoprotein IIb/IIIa and P-selectin leading to aggregation and activation of hPLTs, which were exacerbated by providing physiology-mimicking conditions, including introduction of thrombin, collagen, and high shear stress. Interestingly, intracellular calcium levels in hPLTs were increased upon TiO2NP treatment, which were crucial in TiO2NP-induced hPLT procoagulant activity, activation and aggregation. Moreover, using mice in vivo models, we further confirmed that TiO2NP treatment a reduction in mouse platelet (mPLT) counts, disrupted blood flow, and exacerbated carotid arterial thrombosis with enhanced deposition of mPLT. CONCLUSIONS: Together, our study provides evidence for an ignored health risk caused by TiO2NPs, specifically TiO2NP treatment augments procoagulant activity, activation and aggregation of PLTs via calcium-dependent mechanism and thus increases the risk of AT.

Platelet transfusion enhances pro-aggregatory status shortly after coronary artery bypass grafting (CABG while modulating platelet pro-inflammatory state 1-week post-surgery.

During coronary artery bypass grafting (CABG), the surgical procedure, particularly the manipulation of the major arteries of the heart, induces a significant inflammatory state that may compromise platelet function to the extent that platelet transfusion is required. Given stored platelets as a major source of biological mediators, this study investigates the effects of platelet transfusion on the major pro-aggregatory, pro-inflammatory and immunomodulatory markers of platelets. Platelets from 20 patients, 10 who received platelet transfusion and 10 without, were subjected to flow cytometery where P-selectin and CD40 ligand (CD40L) expressions and PAC-1 binding (activation-specific anti GPIIb/GPIIIa antibody) analysed at five-time points of 24 h before surgery, immediately, 2 h, 24 h and 1 week after surgery. Analysis of intra-platelet transforming growth factor-beta-1 (TGF-ß1) was also conducted using western blotting. Patients with platelet transfusion showed increased levels of P-selectin, CD40L and intra-platelet TGF-ß1 2-h after surgery compared to those without transfusion (p < 0.05). PAC-1 binding was increased 24 h after surgery in transfused patients (p < 0.05). Given the significant post-transfusion elevation of platelet TGF-ß1, P-sel/CD40L reduction in transfused patients a week after was of much interest. This study showed for the first time the significant effects of platelet transfusion on the pro-inflammatory, pro-aggeregatory and immunomodulatory state of platelets in CABG patients, which manifested with immediate, midterm and delayed consequences. While the increased pro-inflammatory conditions manifested as an immediate effect of platelet transfusion, the pro-aggregatory circumstances emerged 24 h post-transfusion. A week after surgery, attenuations of pro-inflammatory markers of platelets in transfused patients were shown, which might be due to the immunomodulatory effects of TGF-ß1.

Western Diet Modifies Platelet Activation Profiles in Male Mice.

The correlation between obesity and cardiovascular disease has long been understood, yet scant investigations endeavored to determine the impact of an obesogenic diet on platelet activation or function. As platelets drive clot formation, the terminus of cardiovascular events, we aimed to elucidate the longitudinal effect of an obesogenic diet on platelet phenotype by assessing markers of platelet activation using flow cytometry. Male, weanling mice were fed either a Western diet (30% kcal sucrose, 40% kcal fat, 8.0% sodium) or Control diet (7% kcal sucrose, 10% kcal fat, 0.24% sodium). At 12, 16 and 20 weeks on diets, platelets were collected and stained to visualize glycoprotein Ibα (GPIbα), P-selectin and the conformationally active state of αIIbß3 (a platelet specific integrin) after collagen stimulation. At all time points, a Western diet reduced GPIbα and αIIbß3 expression in platelets broadly while P-selectin levels were unaffected. However, P-selectin was diminished by a Western diet in the GPIbα- subpopulation. Thus, a Western diet persistently primed platelets towards a blunted activation response as indicated by reduced active αIIbß3 and P-selectin surface expression. This study provides a first look at the influence of diet on platelet activation and revealed that platelet activation is susceptible to dietary intervention.

Targeted nanoparticles triggered by plaque microenvironment for atherosclerosis treatment through cascade effects of reactive oxygen species scavenging and anti-inflammation.

Inflammatory factors and reactive oxygen species (ROS) are risk factors for atherosclerosis. Many existing therapies use ROS-sensitive delivery systems to alleviate atherosclerosis, which achieved certain efficacy, but cannot eliminate excessive ROS. Moreover, the potential biological safety concerns of carrier materials through chemical synthesis cannot be ignored. Herein, an amphiphilic low molecular weight heparin- lipoic acid conjugate (LMWH-LA) was used as a ROS-sensitive carrier material, which consisted of injectable drug molecules used clinically, avoiding unknown side effects. LMWH-LA and curcumin (Cur) self-assembled to form LLC nanoparticles (LLC NPs) with LMWH as shell and LA/Cur as core, in which LMWH could target P-selectin on plaque endothelial cells and competitively block the migration of monocytes to endothelial cells to inhibit the origin of ROS and inflammatory factors, and LA could be oxidized to trigger hydrophilic-hydrophobic transformation and accelerate the release of Cur. Cur released within plaques further exerted anti-inflammatory and antioxidant effects, thereby suppressing ROS and inflammatory factors. We used ultrasound imaging, pathology and serum analysis to evaluate the therapeutic effect of nanoparticles on atherosclerotic plaques in apoe-/- mice, and the results showed that LLC showed significant anti-atherosclerotic effects. Our finding provided a promising therapeutic nanomedicine for the treatment of atherosclerosis.

The Variation in the Traits Ameliorated by Inhibitors of JAK1/2, TGF-ß, P-Selectin, and CXCR1/CXCR2 in the Gata1low Model Suggests That Myelofibrosis Should Be Treated by These Drugs in Combination.

Studies conducted on animal models have identified several therapeutic targets for myelofibrosis, the most severe of the myeloproliferative neoplasms. Unfortunately, many of the drugs which were effective in pre-clinical settings had modest efficacy when tested in the clinic. This discrepancy suggests that treatment for this disease requires combination therapies. To rationalize possible combinations, the efficacy in the Gata1low model of drugs currently used for these patients (the JAK1/2 inhibitor Ruxolitinib) was compared with that of drugs targeting other abnormalities, such as p27kip1 (Aplidin), TGF-ß (SB431542, inhibiting ALK5 downstream to transforming growth factor beta (TGF-ß) signaling and TGF-ß trap AVID200), P-selectin (RB40.34), and CXCL1 (Reparixin, inhibiting the CXCL1 receptors CXCR1/2). The comparison was carried out by expressing the endpoints, which had either already been published or had been retrospectively obtained for this study, as the fold change of the values in the corresponding vehicles. In this model, only Ruxolitinib was found to decrease spleen size, only Aplidin and SB431542/AVID200 increased platelet counts, and with the exception of AVID200, all the inhibitors reduced fibrosis and microvessel density. The greatest effects were exerted by Reparixin, which also reduced TGF-ß content. None of the drugs reduced osteopetrosis. These results suggest that future therapies for myelofibrosis should consider combining JAK1/2 inhibitors with drugs targeting hematopoietic stem cells (p27Kip1) or the pro-inflammatory milieu (TGF-ß or CXCL1).

Antithrombotic Effect of Oil from the Pulp of Bocaiúva-Acrocomia aculeata (Jacq.) Lodd. ex Mart. (Arecaceae).

The study aimed to evaluate the antithrombotic action of Acrocomia aculeata pulp oil (AAPO) in natura, in an in vitro experimental model. AAPO was obtained by solvent extraction, and its chemical characterization was performed by gas chromatography coupled to a mass spectrometer (GC-MS). In vitro toxicity was evaluated with the Trypan Blue exclusion test and in vivo by the Galleria mellonella model. ADP/epinephrine-induced platelet aggregation after treatment with AAPO (50, 100, 200, 400, and 800 µg/mL) was evaluated by turbidimetry, and coagulation was determined by prothrombin activity time (PT) and activated partial thromboplastin time (aPTT). Platelet activation was measured by expression of P-selectin on the platelet surface by flow cytometry and intraplatelet content of reactive oxygen species (ROS) by fluorimetry. The results showed that AAPO has as major components such as oleic acid, palmitic acid, lauric acid, caprylic acid, and squalene. AAPO showed no toxicity in vitro or in vivo. Platelet aggregation decreased against agonists using treatment with different concentrations of AAPO. Oil did not interfere in PT and aPTT. Moreover, it expressively decreased ROS-induced platelet activation and P-selectin expression. Therefore, AAPO showed antiplatelet action since it decreased platelet activation verified by the decrease in P-selectin expression as well as in ROS production.

Comparative Analysis of P-selectin Levels in Psoriasis, Vitiligo, and Nonskin Disease in a Tertiary Care Hospital: A Case-Control Study.

INTRODUCTION: The role and function of P-selectin levels in various inflammatory and immune-mediated diseases have been established. Whether they have an association with inflammatory skin diseases such as vitiligo and psoriasis needs to be established. OBJECTIVE: The objective of this study was to assess P-selectin levels in psoriasis and vitiligo and to compare them with matched controls without skin disease. MATERIALS AND METHODS: The study included a total of 90 subjects with age- and sex-matched - 30 each in psoriasis, vitiligo and 30 controls without skin disease. Psoriasis and vitiligo severity was assessed using the Psoriasis Area and Severity Index and the Vitiligo Area Scoring Index scores. P-selectin levels were assessed and compared among the groups. P-selectin levels were also compared with the severity of psoriasis and vitiligo. Chi-square and analysis of variance tests were used to compare the data. RESULTS: The mean age of subjects was 36.28 ± 11.80 years. Majority of the subjects were males (65.6%). The three groups were matched for age, sex, and other demographics. The mean P-selectin levels were 610.43 ± 134.19, 292.52 ± 60.99, and 158.97 ± 34.76 ng/ml, respectively, in the psoriasis, vitiligo, and control groups, respectively (P < 0.001). No significant association of P-selectin levels was observed with psoriasis severity; however, with increasing vitiligo severity, there was a significant increase in P-selectin levels (P < 0.001). CONCLUSION: Patients with skin diseases have raised P-selectin levels. Within skin diseases, inflammatory diseases such as psoriasis have higher P-selectin levels as compared to autoimmune diseases such as vitiligo. A significant association of P-selectin levels was observed with vitiligo severity but not with psoriasis severity.

Résumé Introduction:Le rôle et la fonction des niveaux de P-sélectine dans diverses maladies inflammatoires et à médiation immunitaire ont été établis. Si leur association avec des maladies inflammatoires de la peau telles que le vitiligo et le psoriasis doit être établie.Objectif:L'objectif L'objectif de cette étude était d'évaluer les niveaux de P-sélectine dans le psoriasis et le vitiligo et de comparer l'anthropo avec des témoins appariés sans maladie cutanée.Matériels et méthodes:L'étude a inclus un total de 90 sujets ­ 30 dans chaque groupe, des sujets de même âge et sexe atteints de psoriasis, de vitiligo. et contrôles sans maladie de peau. La gravité du psoriasis et du vitiligo a été évaluée à l'aide du Psoriasis Area and Severity Index et du Vitiligo. Scores de l'indice de notation de zone. Les niveaux de P-sélectine ont été évalués et comparés entre les groupes. Les niveaux de P-sélectine ont également été comparés aux gravité du psoriasis et du vitiligo. Des tests du chi carré et d'analyse de variance ont été utilisés pour comparer les données.Résultats:L'âge moyen des sujets était de 36,28 ± 11,80 ans. La majorité des sujets étaient des hommes (65,6 %). Les trois groupes ont été appariés en fonction de l'âge, du sexe et d'autres données démographiques. Les taux moyens de P-sélectine étaient respectivement de 610,43 ± 134,19, 292,52 ± 60,99 et 158,97 ± 34,76 ng/ml dans les patients atteints de psoriasis, de vitiligo et de contrôle. groupes, respectivement (P <0,001). Aucune association significative entre les taux de P-sélectine et la gravité du psoriasis n'a été observée; cependant, avec l'augmentation En cas de gravité du vitiligo, il y avait une augmentation significative des taux de P-sélectine ( P < 0,001).Conclusion:les patients atteints de maladies de peau ont augmenté la sélectine P les niveaux. Parmi les maladies de la peau, les maladies inflammatoires telles que le psoriasis ont des taux de sélectine P plus élevés que les maladies auto-immunes telles que comme le vitiligo. Une association significative des taux de P-sélectine a été observée avec la gravité du vitiligo mais pas avec la gravité du psoriasis.

P-selectin Facilitates SARS-CoV-2 Spike 1 Subunit Attachment to Vesicular Endothelium and Platelets.

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.

Total Synthesis of a PSGL-1 Glycopeptide Analogue for Targeted Inhibition of P-Selectin.

The high affinity interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin is mediated by a multimotif glycosulfopeptide (GSP) recognition domain consisting of clustered tyrosine sulfates and a Core 2 O-glycan terminated with sialyl LewisX (C2-O-sLeX). These distinct GSP motifs are much more common than previously appreciated within a wide variety of functionally important domains involved in protein-protein interactions. However, despite the potential of GSPs to serve as tools for fundamental studies and prospects for drug discovery, their utility has been limited by the absence of chemical schemes for synthesis on scale. Herein, we report the total synthesis of GSnP-6, an analogue of the N-terminal domain of PSGL-1, and potent inhibitor of P-selectin. An efficient, scalable, hydrogenolysis-free synthesis of C2-O-sLeX-Thr-COOH was identified by both convergent and orthogonal one-pot assembly, which afforded this crucial building block, ready for direct use in solid phase peptide synthesis (SPPS). C2-O-sLeX-Thr-COOH was synthesized in 10 steps with an overall yield of 23% from the 4-O,5-N oxazolidinone thiosialoside donor. This synthesis represents an 80-fold improvement in reaction yield as compared to prior reports, achieving the first gram scale synthesis of SPPS ready C2-O-sLeX-Thr-COOH and enabling the scalable synthesis of GSnP-6 for preclinical evaluation. Significantly, we established that GSnP-6 displays dose-dependent inhibition of venous thrombosis in vivo and inhibits vaso-occlusive events in a human sickle cell disease equivalent microvasculature-on-a-chip system. The insights gained in formulating this design strategy can be broadly applied to the synthesis of a wide variety of biologically important oligosaccharides and O-glycan bearing glycopeptides.

The effect of near-infrared low-level light on the in vitro quality of platelets during storage.

BACKGROUND AND OBJECTIVES: Near-infrared (NIR) light has been successfully applied to improve the quality of mouse platelets during storage. Because it is suspected that the mitochondria contain the primary photon acceptor, we hypothesized that human platelets for transfusion may be affected similarly and could benefit from NIR light treatment. MATERIALS AND METHODS: The optimal light dose was determined using portions of platelet concentrates (PCs) in PAS-E. A pool-and-split design was used to prepare PCs in PAS-E or plasma (n = 6). On day 1, one unit of both pairs was illuminated with 830 nm light (light-emitting diodes, 15 J/cm2). PCs were stored at 22°C and sampled regularly for analysis. Data were compared with their corresponding controls with a paired two-sided t-test. RESULTS: Illuminated platelets in PAS-E were less activated with significantly lower CD62P expression (day 8: 10.8 ± 1.8 vs. 12.2 ± 2.6, p < 0.05) and lower Annexin A5 binding (day 8: 11.8 ± 1.9 vs. 13.1 ± 2.4, ns). They produced significantly less lactate resulting in a higher pH (days 6-10). ATP content and mitochondrial membrane potential were not affected. Although these trends were also observed for PCs in plasma, the differences did not reach statistical significance as compared with the control group. CONCLUSION: Our study demonstrates that the glycolysis rate of human platelets can be modulated through the use of NIR, possibly through mitochondrial aerobic metabolism, but this requires confirmation. If NIR illumination can be further optimized, it may potentially become a useful tool in situations in which glycolysis and platelet activation are exacerbated.

Removal of endothelial surface-associated von villebrand factor suppresses accelerate datherosclerosis after myocardial infarction.

BACKGROUND: Thromboinflammation involving platelet adhesion to endothelial surface-associated von Willebrand factor (VWF) has been implicated in the accelerated progression of non-culprit plaques after MI. The aim of this study was to use arterial endothelial molecular imaging to mechanistically evaluate endothelial-associated VWF as a therapeutic target for reducing remote plaque activation after myocardial infarction (MI). METHODS: Hyperlipidemic mice deficient for the low-density lipoprotein receptor and Apobec-1 underwent closed-chest MI and were treated chronically with either: (i) recombinant ADAMTS13 which is responsible for proteolytic removal of VWF from the endothelial surface, (ii) N-acetylcysteine (NAC) which removes VWF by disulfide bond reduction, (iii) function-blocking anti-factor XI (FXI) antibody, or (iv) no therapy. Non-ischemic controls were also studied. At day 3 and 21, ultrasound molecular imaging was performed with probes targeted to endothelial-associated VWF A1-domain, platelet GPIbα, P-selectin and vascular cell adhesion molecule-1 (VCAM-1) at lesion-prone sites of the aorta. Histology was performed at day 21. RESULTS: Aortic signal for P-selectin, VCAM-1, VWF, and platelet-GPIbα were all increased several-fold (p < 0.01) in post-MI mice versus sham-treated animals at day 3 and 21. Treatment with NAC and ADAMTS13 significantly attenuated the post-MI increase for all four molecular targets by > 50% (p < 0.05 vs. non-treated at day 3 and 21). On aortic root histology, mice undergoing MI versus controls had 2-4 fold greater plaque size and macrophage content (p < 0.05), approximately 20-fold greater platelet adhesion (p < 0.05), and increased staining for markers of platelet transforming growth factor-ß1 signaling. Accelerated plaque growth and inflammatory activation was almost entirely prevented by ADAMTS13 and NAC. Inhibition of FXI had no significant effect on molecular imaging signal or plaque morphology. CONCLUSIONS: Plaque inflammatory activation in remote arteries after MI is strongly influenced by VWF-mediated platelet adhesion to the endothelium. These findings support investigation into new secondary preventive therapies for reducing non-culprit artery events after MI.

Erianin alleviates LPS-induced acute lung injury via antagonizing P-selectin-mediated neutrophil adhesion function.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium officinale Kimura et Migo, known as "Tiepi Shihu" in traditional Chinese medicine, boasts an extensive history of medicinal use documented in the Chinese Pharmacopoeia. "Shen Nong Ben Cao Jing" records D. officinale as a superior herbal medicine for fortifying "Yin" and invigorating the five viscera. Erianin, a benzidine compound, emerges as a prominent active constituent derived from D. officinale, with the pharmacological efficacy of D. officinale closely linked to the anti-inflammatory properties of erianin. AIM OF THE STUDY: Acute lung injury (ALI) is a substantial threat to global public health, while P-selectin stands out as a promising novel target for treating acute inflammatory conditions. This investigation aims to explore the therapeutic potential of erianin in ALI treatment and elucidate the underlying mechanisms. EXPERIMENTAL DESIGN: The effectiveness of erianin in conferring protection against ALI was investigated through comprehensive histopathological and biochemical analyses of lung tissues and bronchoalveolar lavage fluid (BALF) in an in vivo model of LPS-induced ALI in mice. The impact of erianin on fMLP-induced neutrophil chemotaxis was quantitatively assessed using the Transwell and Zigmond chamber, respectively. To determine the therapeutic target of erianin and elucidate their binding capability, a series of sophisticated assays were employed, including drug affinity responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA), and molecular docking analyses. RESULTS: Erianin demonstrated a significant alleviation of LPS-induced acute lung injury, characterized by reduced total cell and neutrophil counts and diminished total protein contents in BALF. Moreover, erianin exhibited a capacity to decrease proinflammatory cytokine production in both lung tissues and BALF. Notably, erianin effectively suppressed the activation of NF-κB signaling in the lung tissues of LPS- challenged mice; however, it did not exhibit in vitro inhibitory effects on inflammation in LPS-induced human pulmonary microvascular endothelial cells (HPMECs). Additionally, erianin blocked the adhesion and rolling of neutrophils on HPMECs. While erianin did not influence endothelial P-selectin expression or cytomembrane translocation, it significantly reduced the ligand affinity between P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1). CONCLUSIONS: Erianin inhibits P-selectin-mediated neutrophil adhesion to activated endothelium, thereby alleviating ALI. The present study highlights the potential of erianin as a promising lead for ALI treatment.

1.8-cineole prevents platelet activation and aggregation by activating the cAMP pathway via the adenosine A2A receptor.

AIMS: Dysregulated platelet aggregation is a fatal condition in many bacterial- and virus-induced diseases. However, classical antithrombotics cannot completely prevent immunothrombosis, due to the unaddressed mechanisms towards inflammation. Thus, targeting platelet hyperactivation together with inflammation might provide new treatment options in diseases, characterized by immunothrombosis, such as COVID-19 and sepsis. The aim of this study was to investigate the antiaggregatory effect and mode of action of 1.8-cineole, a monoterpene derived from the essential oil of eucalyptus leaves, known for its anti-inflammatory proprieties. MAIN METHODS: Platelet activity was monitored by measuring the expression and release of platelet activation markers, i.e., P-selectin, CD63 and CCL5, as well as platelet aggregation, upon treatment with 1.8-cineole and stimulation with several classical stimuli and bacteria. A kinase activity assay was used to elucidate the mode of action, followed by a detailed analysis of the involvement of the adenylyl-cyclase (AC)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway by Western blot and ELISA. KEY FINDINGS: 1.8-cineole prevented the expression and release of platelet activation markers, as well as platelet aggregation, upon induction of aggregation with classical stimuli and immunological agonists. Mechanistically, 1.8- cineole influences the activation of the AC-cAMP-PKA pathway, leading to higher cAMP levels and vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Finally, blocking the adenosine A2A receptor reversed the antithrombotic effect of 1.8-cineole. SIGNIFICANCE: Given the recognized anti-inflammatory attributes of 1.8-cineole, coupled with our findings, 1.8-cineole might emerge as a promising candidate for treating conditions marked by platelet activation and abnormal inflammation.

P-selectin and C-reactive protein in relation to home blood pressure and coronary calcification: a SCAPIS substudy.

BACKGROUND: Soluble P-selectin (sP-selectin) and high-sensitivity C-reactive protein (hsCRP) have previously been associated with hypertension, but the relation with out-of-office blood pressure (BP) and coronary artery calcification score is unknown. We aimed to examine the relationship between sP-selectin, hsCRP and home BP, as well as coronary artery calcification score and carotid artery plaques. METHODS: In the Swedish CArdioPulmonary bioImage Study (SCAPIS), 5057 randomly selected participants were evaluated with office and home BP using the semi-automatic Omron M10-IT device. For this cross-sectional study, participants with sP-selectin <4 standard deviations above mean and hsCRP <5 mg/l, representing low-grade inflammation, were included. Using generalized linear models, these inflammatory markers were evaluated in relation to BP classifications, as well as coronary artery calcification score and carotid artery plaques. RESULTS: Of participants, 4548 were included in the analyses. The median age was 57.2 (53.4-61.2) years, and 775 (17.0%) reported taking medication for hypertension. Participants in the highest quartile of sP-selectin [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.40-1.98, P  < 0.001] and hsCRP [OR 2.25, (95% CI 1.89-2.60), P  < 0.001] were more likely to have sustained hypertension. Participants in the highest quartile of hsCRP were also more likely to have masked hypertension, OR (95% CI) 2.31 (1.72-3.10), P  < 0.001 and carotid artery plaques, OR (95% CI) 1.21 (1.05-1.38), P  = 0.007. CONCLUSION: Increased sP-selectin and hsCRP were independently associated with sustained hypertension. These findings indicate an association between hypertension and platelet activity, as expressed by sP-selectin.

Evaluation of soluble P-selectin as a predictive biomarker in acute symptomatic pulmonary embolism: Insights from a prospective observational study.

BACKGROUND: Soluble P-selectin (sP-selectin) has been proposed as a potential biomarker for venous thromboembolism (VTE) diagnosis with interesting results. However, its role in predicting early mortality in pulmonary embolism (PE) remains unexplored. METHODS: This observational, prospective, single-center study enrolled consecutive patients aged 18 or older with confirmed acute symptomatic PE and no prior anticoagulation. The study aims to assess the prognostic capacity of sP-selectin measured at the time of PE diagnosis for short-term mortality and major bleeding. RESULTS: A total of 196 patients, with a mean age of 69.1 years (SD 17), were included, of whom 52.6% were male. Within 30 days, 9.7% of patients (n = 19) died, and 5.1% (n = 10) suffered major bleeding. PE risk stratification revealed 4.6% (n = 9) with high-risk PE, 34.7% (n = 68) with intermediate-high-risk PE, 38.3% (n = 75) with intermediate-low-risk PE, and 22.5% (n = 44) with low-risk PE according to the European Society of Cardiology score. Mean plasma sP-selectin levels were comparable between survivors and non-survivors (489.7 ng/mL ±63 vs. 497.3 ng/mL ±51; p = .9). The ROC curve for 30-day all-cause mortality and major bleeding yielded an AUC of 0.49 (95% CI 0.36-0.63) and 0.46 (95% CI 0.24-0.68), respectively. Multivariate and survival analyses were precluded due to lack of significance. CONCLUSIONS: sP-selectin was not useful for predicting short-term mortality or major bleeding in patients with acute symptomatic pulmonary embolism. Further studies are required to clarify the role of sP-selectin in VTE, particularly in prognosticating PE outcomes.

Apolipoprotein A-IV polymorphisms Q360H and T347S attenuate its endogenous inhibition of thrombosis.

Platelets are small anucleate cells that play a key role in thrombosis and hemostasis. Our group previously identified apolipoprotein A-IV (apoA-IV) as an endogenous inhibitor of thrombosis by competitive blockade of the αIIbß3 integrin on platelets. ApoA-IV inhibition of platelets was dependent on the N-terminal D5/D13 residues, and enhanced with absence of the C-terminus, suggesting it sterically hinders its N-terminal platelet binding site. The C-terminus is also the site of common apoA-IV polymorphisms apoA-IV-1a (T347S) and apoA-IV-2 (Q360H). Interestingly, both are linked with an increased risk of cardiovascular disease, however, the underlying mechanism remains unclear. Here, we generated recombinant apoA-IV and found that the Q360H or T347S polymorphisms dampened its inhibition of platelet aggregation in human platelet-rich plasma and gel-filtered platelets, reduced its inhibition of platelet spreading, and its inhibition of P-selectin on activated platelets. Using an ex vivo thrombosis assay, we found that Q360H and T347S attenuated its inhibition of thrombosis at both high (1800s-1) and low (300s-1) shear rates. We then demonstrate a conserved monomer-dimer distribution among apoA-IV WT, Q360H, and T347S and use protein structure modelling software to show Q360H and T347S enhance C-terminal steric hindrance over the N-terminal platelet-binding site. These data provide critical insight into increased cardiovascular risk for individuals with Q360H or T347S polymorphisms.

Proteomic profiling for biomarker discovery in heparin-induced thrombocytopenia.

ABSTRACT: New analytical techniques can assess hundreds of proteins simultaneously with high sensitivity, facilitating the observation of their complex interplay and role in disease mechanisms. We hypothesized that proteomic profiling targeting proteins involved in thrombus formation, inflammation, and the immune response would identify potentially new biomarkers for heparin-induced thrombocytopenia (HIT). Four existing panels of the Olink proximity extension assay covering 356 proteins involved in thrombus formation, inflammation, and immune response were applied to randomly selected patients with suspected HIT (confirmed HIT, n = 32; HIT ruled out, n = 38; and positive heparin/platelet factor 4 [H/PF4] antibodies, n = 28). The relative difference in protein concentration was analyzed using a linear regression model adjusted for sex and age. To confirm the test results, soluble P-selectin was determined using enzyme-linked immunosorbent assay (ELISA) in above mentioned patients and an additional second data set (n = 49). HIT was defined as a positive heparin-induced platelet activation assay (washed platelet assay). Among 98 patients of the primary data set, the median 4Ts score was 5 in patients with HIT, 4 in patients with positive H/PF4 antibodies, and 3 in patients without HIT. The median optical density of a polyspecific H/PF4 ELISA were 3.0, 0.9, and 0.3. Soluble P-selectin remained statistically significant after multiple test adjustments. The area under the receiver operating characteristic curve was 0.81 for Olink and 0.8 for ELISA. Future studies shall assess the diagnostic and prognostic value of soluble P-selectin in the management of HIT.

Improving platelet function following prophylactic platelet transfusion in patients with hematological malignancies.

INTRODUCTION: Platelet transfusion is a standard treatment to prevent bleeding in patients with hematological malignancies. Although transfusions can improve platelet count, their impact on platelet function remains controversial. METHODS: We conducted flow cytometry to assess platelet function before and after transfusion and performed subgroup analyses to examine differences based on blood type, corrected count increment (CCI), and platelet microparticles. RESULTS: Overall, 50 patients who received prophylactic platelet transfusion were enrolled. CD42b expression increased, whereas CD41 expression decreased after transfusion. Apheresis platelets exhibited the lowest expression of PAC-1 and P-selectin when exposed to agonist stimulations. PAC-1 expression increased under high adenosine diphosphate (ADP) stimulation, while P-selectin expression increased under both high ADP and thrombin receptor-activating peptide stimulation. In the subgroup analysis, patients with a CCI >4500 and those with the same blood types exhibited a more significant increase in PAC-1 and P-selectin expression under agonist stimulation. When comparing apheresis platelets collected on different days, only the percentage of platelet-derived microparticles showed a significant increase. CONCLUSION: Prophylactic transfusion improved platelet function. Platelet function significantly improved in patients with a CCI >4500, those with the same blood types as that of apheresis platelets, or those with platelet-derived microparticle levels <4.7%. No significant improvement in platelet function was noted after the transfusion of different blood types with acceptable compatibility or the transfusion of incompatible blood types. Our results suggest that transfusing platelets with the same blood type remains the optimal choice.

Asymmetric dimethylarginine correlates with indicators of prethrombotic state in patients with nonvalvular atrial fibrillation.

OBJECTIVE: The mechanism of asymmetric dimethylarginine (ADMA) in thrombosis in patients with nonvalvular atrial fibrillation (NVAF) is still unclear. Our aim was to investigate the relationship between ADMA and indicators of prethrombotic state in NVAF patients and to analyze the predictive role of ADMA in NVAF thrombosis. METHODS: A total of 192 NVAF patients were continuously selected from January 2023 to October 2023. Plasma ADMA levels were measured by high-performance liquid chromatography. P-selectin (P-sel), von Willebrand factor (vWF), D-dimer (D-D), and plasminogen activator inhibitor-1 (PAI-1) levels were measured by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) levels were measured by the nitrate reductase assay for plasma nitrite/nitrate, then the Griess method (Shanghai Hailian Biotechnology Co., Shanghai, China) was used to calculate plasma NO levels. RESULTS: In our study, ADMA levels were significantly elevated and positively correlated with P-sel, vWF, D-D, and PAI-1, whereas NO levels were significantly negatively correlated with these prethrombotic factors in NVAF. Furthermore, multifactorial logistic regression analysis showed that ADMA and LA diameter were independent predictors of high thrombosis risk (CHA2DS2-VASc ≥2 score) in patients with NVAF. CONCLUSIONS: Our findings suggested that ADMA correlated with the prethrombotic state in NVAF and that reduction of ADMA levels in NVAF patients may be a novel therapeutic strategy for thrombosis risk reduction.