Circulating Platelets as Mediators of Immunity, Inflammation, and Thrombosis

Antithrombotic and anticariogenic activity of peptide fractions from cowpea (Vigna unguiculata) protein hydrolysates

BACKGROUND

Protein-derived peptide fractions can play a key role in the physiological and metabolic regulation and modulation of the body, which suggests that they could be used as functional ingredients to improve health and to reduce the risk of disease. This work aimed to evaluate the in vitro antithrombotic and anticariogenic bioactivity of hydrolysates and protein fractions obtained from cowpea (Vigna unguiculata) by biocatalysis.

RESULTS

Cowpea protein concentrate was hydrolyzed by sequential action with two enzyme systems, Pepsin-Pancreatin or Alcalase-Flavourzyme. There was extensive enzymatic hydrolysis, with degrees of hydrolysis of 34.94% and 81.43% for Pepsin-Pancreatin and Alcalase-Flavourzyme, respectively. The degree of hydrolysis for the control treatments, without the addition of the enzymes Pepsin-Pancreatin and Alcalase-Flavourzyme was 1.1% and 1.2%, respectively. The hydrolysates were subjected to fractionation by ultrafiltration, with five cut-off points according to molecular weight (<1, 1-3, 3-5, 5-10 and >10 kDa). The Alcalase-Flavourzyme hydrolysate led to 100% inhibition of platelet aggregation, while the Pepsin-Pancreatin hydrolysate showed 77.41% inhibition, but this was approximately 100% in the ultrafiltered fractions. The highest anticariogenic activity was obtained with the Pepsin-Pancreatin system, with 61.55% and 56.07% for calcium and phosphorus demineralization, respectively.

CONCLUSION

Hydrolysates and their peptide fractions from Vigna unguiculata exhibited inhibition of platelet aggregation and protection of tooth enamel and have the potential for use in the development of functional products with beneficial health effects. © 2024 Society of Chemical Industry.

Cellular and Molecular Mechanisms Leading to Air Travel-Induced Thrombosis

Venous thromboembolism, characterized by deep vein thrombosis and pulmonary embolism, is the third cardiovascular disease in the world. Deep vein thrombosis occurs when a blood clot forms in areas of impaired blood flow, and it is significantly affected by environmental factors. Local hypoxia, caused by venous stasis, plays a critical role in deep vein thrombosis under normal conditions, and this effect is intensified when the Po2 decreases, such as during air travel or high-altitude exposure. The lower oxygen levels and reduced pressure at high altitudes further contribute to deep vein thrombosis development. These conditions increase the pro-coagulant activity of neutrophils, platelets, and red blood cells, which interact on the surface of activated endothelial cells, promoting clot formation. Understanding the mechanisms involved in thrombus formation when Po2 is reduced, with or without pressure reduction, is crucial for preventing the development of venous thromboembolisms in such conditions and identifying innovative therapeutic targets. This literature review explores the mechanisms involved in thrombus formation related to high-altitude conditions and discusses the pro-coagulant consequences induced by environmental disturbances.

Platelet-derived extracellular vesicles in cardiovascular disease and treatment - from maintaining homeostasis to targeted drug delivery

PURPOSE OF REVIEW

Cardiovascular disease (CVD) remains a major global health burden. Rising incidences necessitate improved understanding of the pathophysiological processes underlying disease progression to foster the development of novel therapeutic strategies. Besides their well recognized role in CVD, platelet-derived extracellular vesicles (PEVs) mediate inter-organ cross talk and contribute to various inflammatory diseases.

RECENT FINDINGS

PEVs are readily accessible diagnostic biomarkers that mirror pathophysiological disease progression but also may confer cardioprotective properties. Monitoring the effects of modulation of PEV signatures through pharmacotherapies has also provided novel insights into treatment efficacy. Furthermore, exploiting their inherent ability to infiltrate thrombi, atherosclerotic plaques and solid tumours, PEVs as well as platelet-membrane coated nanoparticles are emerging as novel effective and targeted treatment options for CVD and cancer.

SUMMARY

Collectively, in-depth characterization of PEVs in various diseases ultimately enhances their use as diagnostic or prognostic biomarkers and potential therapeutic targets, making them clinically relevant candidates to positively impact patient outcomes.

Demographic diversity in platelet function and response to antiplatelet therapy

Recent studies have highlighted the complexity of platelet biology, revealing their diverse roles beyond hemostasis. Pathological platelet activation is now recognized as a key contributor to thrombosis and inflammation that are both central to cardiovascular disease (CVD). Emerging research emphasizes the significant impact of demographic factors - such as age, sex, race, and ethnicity - on CVD risk and responses to antiplatelet therapies. These population-based differences, shaped by genetic and non-genetic factors, highlight the need for reevaluation of antiplatelet strategies. We address current knowledge and emphasize the pressing need for further research into platelet biology and cardiovascular outcomes across diverse populations. In this review we advocate for tailored therapeutic approaches in CVD based on the recent demographic-focused findings.

The biological role and future therapeutic uses of nitric oxide in extracorporeal membrane oxygenation, a narrative review

BACKGROUND

Nitric oxide (NO) is a gas naturally produced by the human body that plays an important physiological role. Specifically, it binds guanylyl cyclase to induce smooth muscle relaxation. NO's other protective functions have been well documented, particularly its protective endothelial functions, effects on decreasing pulmonary vascular resistance, antiplatelet, and anticoagulation properties. The use of nitric oxide donors as vasodilators has been known since 1876. Inhaled nitric oxide has been used as a pulmonary vasodilator and to improve ventilation perfusion matching since the 1990s. It is currently approved by the United States Food and Drug Administration for neonates with hypoxic respiratory failure, however, it is used off-label for acute respiratory distress syndrome, acute bronchiolitis, and COVID-19.

PURPOSE

In this article we review the currently understood biological action and therapeutic uses of NO through nitric oxide donors such as inhaled nitric oxide. We will then explore recent studies describing use of NO in cardiopulmonary bypass and extracorporeal membrane oxygenation and speculate on NO's future uses.

Hemogram and inflammatory indices in pain-free periods in migraine patients without aura

OBJECTIVES

Since neurogenic inflammation and hemoconcentration have a prominent role in the pathophysiology of migraine, evaluation of hemogram parameters and indices showing inflammation can yield important information. In this study, we have investigated blood cell counts and ratios, systemic inflammation index (SII), systemic inflammation response index (SIRI) and red cell index (RCI) in the painless periods between pain attacks in patients with episodic migraine without aura.

METHODS

Hemogram data of both 309 patients diagnosed with migraine without aura related to pain-free periods and 199 healthy individuals were retrospectively retrieved from hospital records. Data related to erythrocyte, leukocyte, lymphocyte, platelet, monocyte, eosinophil counts; hemoglobin, hematocrit, mean corpuscular volume, red blood cell distribution width (RDW), mean platelet volume (MPV), neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, monocyte/lymphocyte ratio (MLR), and neutrophil/monocyte ratio, SII, SIRI and RCI values were scanned to reveal intergroup differences in terms of these parameters.

RESULTS

A comparison of laboratory parameters revealed that certain indices differed significantly between the migraine and control groups. MLR (p = 0.005) and RDW (p < 0.001) values were significantly lower, while platelet (p = 0.016), MPV (p < 0.001) and hematocrit (p = 0.014) were significantly higher in the migraine patient group compared to the control group. There was no significant difference between the two groups regarding other parameters.

DISCUSSION

Higher hematocrit, platelet, mean platelet volume and lower monocyte/lymphocyte ratio values in this study support that hemoconcentration and chronic inflammation persist even in the absence of pain attacks in migraine patients without aura.

Platelet signaling in immune landscape: comprehensive mechanism and clinical therapy

Platelets are essential for blood clotting and maintaining normal hemostasis. In pathological conditions, platelets are increasingly recognized as crucial regulatory factors in various immune-mediated inflammatory diseases. Resting platelets are induced by various factors such as immune complexes through Fc receptors, platelet-targeting autoantibodies and other platelet-activating stimuli. Platelet activation in immunological processes involves the release of immune activation stimuli, antigen presentation and interaction with immune cells. Platelets participate in both the innate immune system (neutrophils, monocytes/macrophages, dendritic cells (DCs) and Natural Killer (NK) cells and the adaptive immune system (T and B cells). Clinical therapeutic strategies include targeting platelet activation, platelet-immune cell interaction and platelet-endothelial cell interaction, which display positive development prospects. Understanding the mechanisms of platelets in immunity is important, and developing targeted modulations of these mechanisms will pave the way for promising therapeutic strategies.

Platelet's plea to Immunologists: Please do not forget me

Platelets are non-nucleated mammalian cells originating from the cytoplasmic expulsion of the megakaryocytes. Megakaryocytes develop during hematopoiesis through megakaryopoiesis, whereas platelets develop from megakaryocytes through thrombopoiesis. Since their first discovery, platelets have been studied as critical cells controlling hemostasis or blood coagulation. However, coagulation and innate immune response are evolutionarily linked processes. Therefore, it has become critical to investigate the immunological functions of platelets to maintain immune homeostasis. Advances in immunology and platelet biology research have explored different critical roles of platelets, including phagocytosis, release of different immune mediators, and controlling functions of different immune cells by direct interaction and immune mediators. The current article discusses platelet's development and their critical role as innate immune cells, which express different pattern recognition receptors (PRRs), recognizing different pathogen or microbe-associated molecular patterns (PAMPs or MAMPs) and death/damage-associated molecular patterns (DAMPs) and their direct interactions with innate and adaptive immune cells to maintain immune homeostasis.

Tumor metastasis and recurrence: The role of perioperative NETosis

Although surgical resection of tumor mass remains the mainstay of curative therapeutic management for solid tumors, accumulating studies suggest that these procedures promote tumor recurrence and metastasis. Regarded as the first immune cells to fight against infectious or inflammatory insults from surgery, neutrophils along with their ability of neutrophil extracellular traps (NETs) production has attracted much attention. A growing body of evidence suggests that NETs promote cancer metastasis by stimulating various stages, including local invasion, colonization, and growth. Therefore, we discussed the mechanism of NETosis induced by surgical stress and tumor cells, and the contribution of NETs on tumor metastasis: aid in the tumor cell migration and proliferation, evasion of immune surveillance, circulating tumor cell adhesion and establishment of a metastatic niche. Lastly, we summarized existing NET-targeting interventions, offering recent insights into potential targets for clinical intervention.

Biphasic Effect of Thyroid Hormone on Megakaryopoiesis and Platelet Production

Background: Abnormal platelet counts are frequently observed in patients with thyroid dysfunction; however, the direct impact of thyroid hormones on thrombopoiesis remains largely undefined. Methods: This study elucidates the dose-response effect of the thyroid hormone triiodothyronine (T3) on megakaryocyte (MK) development and thrombopoiesis using both a murine model of hyperthyroidism/hypothyroidism and in vitro cultures of human cord blood CD34+ cell-derived MKs. After the application of inhibitors to MKs, the examination of total and phosphorylated protein levels of the phosphoinositide 3-kinase (PI3K)/AKT pathway was utilized to assess the specific mechanisms of T3 action. The use of autophagy dual-staining lentivirus and transmission electron microscopy was employed to evaluate the impact of T3 on the autophagy flux in MKs. Mouse whole-body irradiation and bone marrow transplantation models are applied to assess the influence of T3 on the recovery of MKs/platelets in vivo. Results: We found that physiological or slightly elevated thyroid hormone levels are essential for sustaining MK development and thrombopoiesis, primarily through the TRα-PI3K/AKT signaling pathway. In contrast, supraphysiological thyroid hormone concentrations induce MK apoptosis via excessive autophagy, thereby reducing platelet production. Conclusions: Here, we present evidence that the thyroid hormone influences MK development and platelet production in a concentration-dependent manner, exhibiting a dualistic role. Our discoveries shed new light on the intricate relationship between thyroid hormones and platelet formation, offering novel perspectives on the pathophysiological consequences of thyroid disorders.

Platelet related gene IQGAP1 contributes to the onset and abnormal immune landscape of ischemic stroke patients

INTRODUCTION

Ischemic stroke (IS) is a complex illness resulting from a combination of numerous environmental and genetic risk factors. Recent reports have shed light on the vital role that platelets play in the pathophysiology of IS. Here, we aimed to explore the potential platelet-related genes in IS and investigate the effect of platelet-related genes in the immune microenvironment of IS.

METHODS

The data of IS were retrieved from the Gene Expression Omnibus database. Firstly, we screened the platelet-related genes that were correlated with the onset of IS using differential expression analysis, enrichment analyses, and protein-protein interaction (PPI) network. Moreover, we analyzed the clinical value and functional information of platelet-related genes in IS. Finally, we explored the correlation between platelet-related genes and immune cells' infiltration.

RESULTS

Ten platelet-related genes that were correlated with the onset of IS were identified, among which IQGAP1 was located at the core of the PPI network. IQGAP1 was found to be expressed in the normal brain tissue and its expression was significantly elevated in IS samples. The area under the curve (AUC) values for IQGAP1 in both the GSE16561 and GSE58294 datasets were close to 1. IQGAP1 knockdown might increase OGD/R‑induced HT22 cell viability. Additionally, FoxO signaling pathway, NOD-like receptor signaling pathway, Phagosome and Platelet activation pathways were significantly activated in IS patients with high IQGAP1 expression compared to those with low IQGAP1 expression. The IS patients in the IQGAP1high and IQGAP1low groups showed dramatically different proportions of immune cells and immune-related functions, and the IQGAP1 expression was correlated with the immune cell' infiltration in IS.

CONCLUSIONS

In this study, we identified the IQGAP1 might serve as a potential diagnostic marker for IS, and the IQGAP1 expression was very relevant in determining the immune cell' infiltration in IS patients.

Relationship between neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio and osteoporosis in postmenopausal type 2 diabetic patients: A retrospective study

Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR) are newly discovered inflammatory markers in recent years. To explore the relationship between NLR, MLR, PLR, and bone mineral density (BMD), as well as osteoporosis (OP), in postmenopausal patients with type 2 diabetes mellitus (T2DM). 320 postmenopausal patients with T2DM who were admitted to the Department of Endocrinology and Metabolic Diseases of our hospital from January 2022 to January 2024 for treatment were included in this retrospective study. The patients were divided into 3 groups according to the BMD: normal bone mass group (n = 109), osteopenia group (n = 99), and OP group (n = 112). Clinical data and blood laboratory parameters were collected from the patients. The NLR, MLR, and PLR were calculated. Statistically significant differences were found in the comparison of NLR, MLR, and PLR among the 3 groups of patients (P < .001). The OP group had higher NLR, MLR, and PLR than the normal bone mass group and the osteopenia group. NLR, MLR, and PLR were negatively correlated with BMD at the lumbar spine (L1-L4), left femoral neck, and left hip, respectively. Analysis revealed that elevated levels of NLR and PLR were independent risk factors for OP in postmenopausal patients. The results of the receiver operating characteristic curve analysis indicated that the area under the curve (AUC) for NLR was higher than that of PLR. Combined use of NLR and PLR resulting in an improved AUC of 0.904. Neutrophils produce mediators such as interferon-gamma (IFN-γ), interleukin-6 (IL-6), interleukin-1 (IL-1), and receptor activator of nuclear factor kappa-B ligand (RANKL), which increase the number and activity of osteoclasts. Peripheral blood monocytes play a vital role in osteoclastogenesis as osteoclast precursors. The BMD of postmenopausal T2DM patients is negatively correlated with NLR, MLR, and PLR. NLR and PLR can both serve as predictive indicators for the occurrence of OP in postmenopausal T2DM patients.

Inflammation and nutritional status in relation to mortality risk from cardio-cerebrovascular events: evidence from NHANES

Objective

Inflammation and nutritional status are closely associated with the mortality risk of survivors of cardio-cerebrovascular events. This study aims to evaluate the relationship between inflammation and nutritional indices and mortality among, identifying the most predictive indices.

Methods

This study included cohort data of the survivors of major adverse cardiovascular and cerebrovascular events (MACCE) from the National Health and Nutrition Examination Survey (NHANES) in 1999-2010. MACCE is defined as a composite of myocardial infarction, heart failure and stroke, and at least one of the three events occurs. The main outcomes were all-cause mortality and cardiovascular mortality. Kaplan-Meier analysis and receiver operating characteristic curves were used to compare the correlation between seven inflammatory nutritional indices (such as Advanced Lung Cancer Inflammation Index, ALI) and mortality among the survivors. A multivariable-adjusted Cox regression and restricted cubic splines analysis identified the most predictive index, with the optimal number of nodes determined by the Akaike information criterion. Subgroup and sensitivity analyses were conducted to assess model stability.

Results

A total of 2,045 MACCE survivors were included. The higher levels of ALI and serum albumin were significantly associated with lower risks of all-cause and cardiovascular mortality among these individuals. Increases in C-reactive protein to Lymphocyte Ratio, Neutrophil to Serum Albumin Ratio, Neutrophil-to-Lymphocyte Ratio, Systemic Immune-Inflammation Index (SII), and C-reactive protein were similarly correlated with higher mortality risk. ALI outperformed other indices, displaying a distinct L-shaped nonlinear relationship with both all-cause and cardiovascular mortality among MACCE survivors, with an inflection point at 90 indicating the lowest risk. To the left of this inflection, each unit increase in ALI was associated with a 1.3% decrease in all-cause and cardiovascular mortality risk among MACCE patients. To the right, the risk might increase by 0.2%, although the change was not statistically significant. Subgroup analyses and sensitivity analyses showed that the association between ALI and risk of mortality remained stable in most MACCE survivor populations.

Conclusion

Routine and dynamic monitoring of ALI is helpful for clinicians to assess the mortality risk among MACCE survivors. Anti-inflammatory therapies and appropriate nutritional support are crucial for reducing mortality in these individuals.

Systemic immune-inflammation index and long-term mortality in patients with hypertension: a cohort study

OBJECTIVE

The objective of this study was to examine the relationship between systemic inflammation and long-term mortality in patients with hypertension.

METHODS

The study employed a retrospective cohort design. The study population was derived from the National Health and Nutrition Examination Survey (NHANES), and the mortality data for this population was acquired from the National Death Index (NDI) database. Systemic inflammation was quantified by the Systemic Immune Inflammation Index (SII) and the Systemic Inflammatory Response Index (SIRI), which were then categorized into four groups (Q1-Q4, with Q4 representing the highest level of SII or SIRI). Weighted Cox regression models were constructed to investigate the association between mortality and SII and SIRI, with hazard ratios (HRs) subsequently calculated.

RESULTS

A total of 7431 participants were included in the analysis. The highest quantile (Q4) of SII was associated with a higher risk of all-cause mortality (hazard ratio 1.36, 95% CI 1.1-1.69, P < 0.001). After adjustment for important covariates, the association remained significant (hazard ratio 1.70, 95% CI 1.27-2.30, P < 0.001). The highest quantile (Q4) of SIRI was also associated with the highest risk of mortality (hazard ratio 2.11, 95% CI 1.64-2.70, P < 0.001), and this association remained significant after adjustment for important covariates (hazard ratio 1.64, 95% CI 0.61-1.22, P = 0.001).

CONCLUSION

Both SII and SIRI scores were found to be associated with mortality rates in patients with hypertension. The findings suggest that these scores may serve as complementary biomarkers to the neutrophil-to-lymphocyte ratio (NLR) for assessing mortality risk in patients with hypertension. Further investigation is warranted to elucidate the underlying mechanisms that underpin this association.

Platelet Reactivity to Zika and Dengue Non-Structural Protein 1 (NS1) Assessed by Flow Cytometry, Atomic Force Microscopy, and Quartz Crystal Microbalance

BACKGROUND

Platelets, besides being traditionally associated with hemostasis, have been recently positioned as immune cells. Alterations in platelet number and function have been reported in some viral infections. Zika virus (ZIKV) and Dengue virus (DENV) are arboviruses that encode for a non-structural protein 1 (NS1). NS1 is mainly involved in the viral replication process and can also be secreted by infected cells and has been associated with immune response evasion. The assessment of platelet reactivity against these viral agents and their proteins, through the use of different innovative technologies such as flow cytometry (FC), atomic force microscopy (AFM), and quartz crystal microbalance (QCM), will allow further study of the pathophysiology of these emerging diseases.

AIM

The aim of this study was to assess platelet reactivity to ZIKV and DENV NS1 protein through the use of FC, AFM, and QCM.

METHODS

Platelet-rich plasma (PRP) was stimulated with ZIKV and DENV NS1 protein in individual assays. The expression of P-selectin and the activity of the glycoprotein IIb-IIIa, platelet activation markers, were assessed by FC, morphological changes were assessed by AFM, and interaction between NS1 protein and platelet were evaluated by QCM.

RESULTS

An increased expression of P-selectin and GP IIb-IIIa activity (p < 0.001) was observed when PRP was stimulated with ZIKV and DENV NS1 proteins. AFM images showed an increase in cell size and the appearance of pseudopods upon stimulation with the viral proteins. QCM results showed a significant increase in the oscillation frequency of the quartz precoated with ZIKV or DENV NS1 when PRP was injected (p < 0.001).

CONCLUSION

FC, AFM, and QCM are techniques that can be used in the study of platelet response to viral structures such as NS1 protein, broadening the range of existing methodologies in the study of these cells. It is imperative to study platelets in arboviral infections to better understand their involvement in these diseases.

High-Dimensional Single-Cell Mass Cytometry Demonstrates Differential Platelet Functional Phenotypes in Infants With Congenital Heart Disease

BACKGROUND

Congenital heart disease (CHD) is a group of complex heart defects associated with hematologic abnormalities, including increased risk of thrombotic and bleeding events. Past studies have observed evidence of platelet hyperreactivity, while other studies showed decreased platelet activation in patients with CHD. The goal of this study was to develop a mass spectrometry approach to characterize single platelets in infants with CHD and identify potential etiology for such discrepant results.

METHODS

We enrolled 19 infants with CHD along with 21 non-CHD controls at Yale New Haven Children's Heart Center. A single-cell high-dimensional mass cytometry method was developed to quantitatively interrogate platelet surface markers in whole blood. Additionally, plasma cytokine analysis was performed through a multiplexed panel of 52 vascular and inflammatory markers to assess for platelet releasates.

RESULTS

We found that infants with CHD had significant differences in platelet activation and functional markers by mass cytometry compared with non-CHD controls. Based on cell surface markers, we classified the platelets into 8 subpopulations (P0 to P7). Distinct subpopulations of platelets (P1, P4, and P5) exhibiting decreased aggregatory phenotype but altered secretory phenotypes were also identified and found to be more abundant in the blood of infants with CHD. Electron microscopy identified increased proportion of hypogranular platelets in CHD. Moreover, cytokine analysis demonstrated an overall increase in plasma cytokines and biomarkers in CHD, including IL (interleukin)-6, IL-8, IL-27, RANTES (regulated upon activation, normal T cell expressed and secreted), and VWF (von Willebrand factor), which are expressed in platelet granules and can be released upon activation.

CONCLUSIONS

We developed a robust mass cytometry approach to identify platelet phenotypic heterogeneity. Infants with CHD had alterations in distinct subpopulations of platelets with overall reduced aggregatory phenotype and secretory dysfunction. These findings suggest that platelets in infants with CHD may be exhausted due to persistent stimulation and may explain both bleeding and thrombotic vascular complications associated with CHD.

Decrease in platelet count in patients with AKI and its association with major adverse kidney events

INTRODUCTION

A reduction in platelet count in critically ill patients is a marker of severity of the clinical condition. However, whether this association holds true in acute kidney injury (AKI) is unknown. We analyzed the association between platelet reduction in patients with AKI and major adverse kidney events (MAKE).

METHODS

In this retrospective cohort, we included AKI patients at the Hospital Civil of Guadalajara, in Jalisco, Mexico. Patients were divided according to whether their platelet count fell >21% during the first 10 days. Our objectives were to analyze the associations between a platelet reduction >21% and MAKE at 10 days (MAKE10) or at 30-90 days (MAKE30-90) and death.

RESULTS

From 2017 to 2023, 400 AKI patients were included, 134 of whom had a > 21% reduction in platelet count. The mean age was 54 years, 60% were male, and 44% had sepsis. The mean baseline platelet count was 194 x 103 cells/µL, and 65% of the KDIGO3 patients met these criteria. Those who underwent hemodialysis (HD) had lower platelet counts. After multiple adjustments, a platelet reduction >21% was associated with MAKE10 (OR 4.2, CI 2.1-8.5) but not with MAKE30-90. The mortality risk increased 3-fold (OR 2.9, CI 1.1-7.7, p = 0.02) with a greater decrease in the platelets (<90 x 103 cells/µL). As the platelets decreased, the incidence of MAKE was more likely to increase. These associations lost significance when accounting for starting HD.

CONCLUSION

In our retrospective cohort of patients with AKI, a > 21% reduction in platelet count was associated with MAKE. Our results are useful for generating hypotheses and motivating us to continue studying this association with a more robust design.

Viral coagulation: pushing the envelope

Many virus types affect the blood clotting system with correlations to pathology that range widely from thrombosis to hemorrhage linking to inflammation. Here we overview the intricate crosstalk induced by infection between proteins on the virus encoded by either the host or virus genomes, coagulation proteins, platelets, leukocytes, and endothelial cells. For blood-borne viruses with an outer covering acquired from the host cell, the envelope, a key player may be the cell-derived trigger of coagulation on the virus surface, tissue factor (TF). TF is a multifunctional transmembrane cofactor that accelerates factor (F)VIIa-dependent activation of FX to FXa, leading to clot formation. However, the nascent TF/FVIIa/FXa complex also facilitates G protein-coupled modulation of cells via protease-activated receptor 2. As a viral envelope constituent, TF can bypass the physiological modes of regulation, thereby initiating the activation of neighboring platelets, leukocytes, and endothelial cells. A thromboinflammatory environment is predicted due to feedback amplification in response to cellular release of cytokines, procoagulant proteins, neutrophil extracellular traps, and stimulus-induced accessibility of adhesive receptors, resulting in cellular aggregates. The pathobiological effects of thromboinflammation ultimately contribute to innate and adaptive immunity for viral clearance. In contrast, the preceding stages of viral infection may be enhanced via the TF-protease axis.

Antiplatelet effects of the CEACAM1-derived peptide QDTT

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) restricts platelet activation via platelet collagen receptor GPVI/FcRγ-chain. In this study, screening against collagen-induced platelet aggregation was performed to identify functional CEACAM1 extracellular domain fragments. CEACAM1 fragments, including Ala-substituted peptides, were synthesized. Platelet assays were conducted on healthy donor samples for aggregation, cytotoxicity, adhesion, spreading, and secretion. Mice were used for tail bleeding and FeCl3-induced thrombosis experiments. Clot retraction was assessed using platelet-rich plasma. Extracellular segments of CEACAM1 and A1 domain-derived peptide QDTT were identified, while N, A2, and B domains showed no involvement. QDTT inhibited platelet aggregation. Ala substitution for essential amino acids (Asp139, Thr141, Tyr142, Trp144, and Trp145) in the QDTT sequence abrogated collagen-induced aggregation inhibition. QDTT also suppressed platelet secretion and "inside-out" GP IIb/IIIa activation by convulxin, along with inhibiting PI3K/Akt pathways. QDTT curtailed FeCl3-induced mesenteric thrombosis without significantly prolonging bleeding time, implying the potential of CEACAM1 A1 domain against platelet activation without raising bleeding risk, thus paving the way for novel antiplatelet drugs.

Response of platelet count in the US population following exposure to BDEs and BB: A cross-sectional analysis of database of NHANES (2007-2016)

Brominated flame retardants (BFRs) are environmental pollutants linked to health risks, including increased platelet (PLT) levels that may elevate the risk of thrombosis and cardiovascular diseases. This study examined the association between BFR exposure and PLT levels among 5831 adult participants from the National Health and Nutrition Examination Survey (NHANES) (2007-2016). Of the 12 BFRs analyzed, BB153, BDE17, BDE85, BDE154, BDE183, and BDE209 showed significant positive correlations with PLT levels (p < 0.05), with BDE17 demonstrating the strongest correlation (Spearman's coefficient = 0.122). After adjusting for confounders, all BFRs except BDE153 remained significantly associated with elevated PLT levels. Restricted cubic spline analysis indicated varying associations, with BDE99, BDE183, and BDE209 showing an "S"-shaped relationship, while BB153, BDE17, and BDE66 presented an inverted "J"-shaped relationship. BDE153 exhibited a "U"-shaped relationship with PLT level. Both weighted quantile sum regression and quantile-based g-computation confirmed that BFR mixtures positively correlated with PLT levels, with BDE17 as the most significant contributor. Our findings suggest that BFR exposure is associated with increased PLT levels, indicating a potential risk for thrombosis and related cardiovascular conditions.

Activation of AMPK in platelets promotes the production of offspring

Platelets are terminally differentiated anucleated cells, but they still have cell-like functions and can even produce progeny platelets. However, the mechanism of platelet sprouting has not been elucidated so far. Here, we show that when platelet-rich plasma(PRP) was cultured at 37°C, platelets showed a spore phenomenon. The number of platelets increased when given a specific shear force. It is found that AMP-related signaling pathways, such as PKA and AMPK are activated in platelets in the spore state. Meanwhile, the mRNA expression levels of genes, such as CNN3, CAPZB, DBNL, KRT19, and ESPN related to PLS1 skeleton proteins also changed. Moreover, when we use the AMPK activator AICAR(AI) to treat washed platelets, cultured platelets can still appear spore phenomenon. We further demonstrate that washed platelets treated with Forskolin, an activator of PKA, not only platelet sprouting after culture but also the AMPK is activated. Taken together, these data demonstrate that AMPK plays a key role in the process of platelet budding and proliferation, suggesting a novel strategy to solve the problem of clinical platelet shortage.

Non-linear relationship between platelet count and 28-day mortality in critically ill patients with infective endocarditis: a retrospective cohort study from MIMIC IV database

Background

The relationship between platelet count and 28-day mortality in critically ill patients with infective endocarditis (IE) is currently not well established.

Objective

This study aims to investigate the impact of platelet count on 28-day mortality in critically ill patients with infective endocarditis.

Methods

A retrospective cohort study was conducted involving 450 participants diagnosed with infective endocarditis and admitted to intensive care units (ICU). Vital signs, laboratory parameters and comorbidity were collected for all participants to analyze the association between platelet count and 28-day mortality. In order to assess the independent association between platelet count and 28-day mortality, we employed multivariable cox hazard regression analyses and smooth curve fitting. A further analysis was conducted using a two-piecewise linear regression model to examine the nonlinear association between platelet count and in-hospital mortality.

Results

A total of 450 critically ill patients with infective endocarditis were included in the study. The mean age was 57.4 years, and 64.2% were male. The overall 28-day mortality rate was 20%. A non-linear relationship was observed between platelet count and 28-day mortality. Two different slopes were identified, with correlations between platelet count and 28-day mortality in patients with IE differing significantly below and above the inflection point, which was approximately 141 K/µl. On the left side of the inflection point, the hazard ratio was 0.990 (hazard ratio: 0.990, 95% confidence interval: 0.982-0.997, p = 0.006). However, on the right side of the inflection point, the hazard ratio increased marginally to 1.0004 (HR: 1.0004, 95% CI: 0.997-1.004, p = 0.825). Notably, the association lacked statistical significance on the right side of the inflection point.

Conclusion

A nonlinear association between platelet count and 28-day mortality was observed in critically ill patients with infective endocarditis. The optimal platelet count associated with the lowest risk of 28-day mortality was above 141 k/µl.

Establishment and evaluation of nomogram for predicting acute respiratory distress syndrome in meconium-stained amniotic fluid neonates

OBJECTIVE

To delineate risk factors and develop a predictive nomogram for acute respiratory distress syndrome (ARDS) in neonates exposed to meconium-stained amniotic fluid (MSAF).

METHODS

We conducted a comprehensive retrospective analysis of neonates with MSAF, classifying them into ARDS and non-ARDS groups based on the onset of ARDS within the first week after birth. Clinical and laboratory data are collected to screen the risk factors for ARDS in MSAF neonates, multivariate logistic regression was performed to identify independent predictors and establish a nomogram to predict the occurrence of neonatal ARDS.

RESULTS

We recognized five variables as independent risk factors for ARDS with MSAF neonates via logistic regression analysis, consisting of 1-min Apgar score (Apgar 1 min), white blood cell (WBC), platelet (PLT), red cell distribution width (RDW) and serum calcium (Ca). These predictors were integrated into a nomogram designed to estimate the individual risk of ARDS development in neonates. The predictive model achieved a C-index of 0.942 (95% CI: 0.915-0.970), indicating high predictive accuracy. Additionally, the nomogram was internally validated, demonstrating excellent calibration and practical utility for clinical decision-making.

CONCLUSIONS

The validated nomogram, based on five pivotal factors, provides clinicians with a reliable tool for early identification and management of ARDS in MSAF neonates, potentially improving outcomes by facilitating timely and appropriate therapeutic interventions.

Unveiling the hidden link: elevated platelets and T cell subsets in 5% of moderate COVID-19 patients 48 days post-onset

Introduction

Platelets are hyperactived during acute COVID-19, promoting clotting and modulating immune-cell responses. Immune thrombocytopenia in adults can manifest as an uncommon complication resulting from various viral infections or as a rare adverse event associated with vaccination. However, their role in convalescent COVID-19 patients remains underexplored. This study examines platelet dynamics early in the pandemic, 48 days post-symptom onset, in unvaccinated patients.

Methods

This longitudinal study included 298 unvaccinated COVID-19 patients (17 mild, 281 moderate) from multiple centers. Clinical evaluations and peripheral lymphocyte subset analyses via flow cytometry were conducted upon admission and on day 48 post-symptom onset (DPSO 48).

Results

At DPSO 48, 5.3% of moderate COVID-19 patients exhibited high platelet counts (>300×109/L), associated with elevated total T-cells (26.4%), CD4 T-cells (24.4%), CD8 T-cells (36.9%), and Tregs (33.9%) compared to patients with normal platelet counts. However, the CD4/CD8 T-cell ratio and T-cell subset frequencies remained unaffected, indicating ongoing T-cell homeostasis restoration. Additionally, a significant positive correlation (r=0.636, p=0.03) was found between platelet counts and B cells in patients with elevated platelet counts.

Discussion

Platelets may play a pivotal role in immune regulation during the recovery phase of COVID-19. Targeting platelets and their secreted mediators could improve immune balance in patients with immune disorders, highlighting a potential therapeutic approach for enhancing recovery in post-COVID-19 patients.

Predictive role of the peripheral blood inflammation indices neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immunoinflammatory index (SII) for age-related cataract risk

The novel inflammatory markers neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immunoinflammatory index (SII) have not yet been used in the study of age-related cataracts. The aim of this study was to investigate the possible relationships between the NLR, PLR, and SII and age-related cataracts. In the 2005-2008 National Health and Nutrition Examination Survey (NHANES) cross-sectional surveys, we collected complete information on blood counts, whether cataract surgery had been performed, and baseline information for adults. We investigated the independent interactions between the inflammatory markers NLR, PLR, and SII and age-related cataracts via weighted multivariate regression analyses and subgroup analyses. Smoothed curve fitting was performed to identify nonlinear associations and saturation effects between inflammation indices and cataract risk. Finally, receiver operating characteristic (ROC) curves were plotted for factors significantly associated with the development of cataracts to identify the optimal diagnostic inflammation index. This study included 8887 participants without cataracts and 935 participants with cataracts. Multivariate logistic regression analyses after adjusting for covariates revealed that a high SII (OR = 1.000, 95% CI = 1.000-1.000; P = 0.017) and high NLR (OR = 1.065, 95% CI = 1.000-1.134; P = 0.048) were independent risk factors for cataracts. Subgroup analyses did not reveal interactions between the SII, NLR, or cataract and covariates. Smoothed curve fits of the relationships between the SII or NLR and cataracts did not show positive significant saturating effect values for any of the variables. The ROC curve revealed some diagnostic value for cataracts for both the SII (AUC = 0.549, P < 0.001) and the NLR (AUC = 0.603, P < 0.001), but both had weak diagnostic value. Our study suggests that the SII and NLR are independent risk factors for cataracts in U.S. adults, but no such associations was identified between the PLR and cataracts.

Observational Analyses of Ex Vivo Native American Platelet Responses

Platelet activation plays an essential role in clot formation to prevent blood loss following vascular damage. In pathologic conditions, platelet activation can lead to obstructive clots, disrupting blood flow and resulting in thrombosis. Native Americans suffer disproportionately from arterial disease and previous research has shown that Blacks are enriched in genetic polymorphisms that correlate with higher platelet reactivity contributing to an increased risk for thrombosis. Therefore, the current study sought to determine phenotypic variations in Native American platelet responses following stimulation with agonists, simulating vascular damage. Several donors from a small cohort of Native Americans showed atypical robust platelet aggregation when stimulated with submaximal concentrations of agonists. Further, when comparing α-granule secretion, a specific marker of platelet activation, Native Americans were more likely to have elevated responses to multiple agonist conditions of stimulation compared to Whites. Interestingly, there were no noticeable differences in integrin activation between Native Americans and Whites. Our study is the first to observe elevated Native American platelet responses compared to Whites, supporting further mechanistic studies and investigation of treatment approaches for the prevention of thrombosis.

Relationship Between the Systemic Immune-Inflammation Index and Deep Venous Thrombosis After Spinal Cord Injury: A Cross-Sectional Study

Purpose

To explore the relationship between the systemic immune-inflammation index (SII) and deep venous thrombosis (DVT) in patients with spinal cord injury (SCI).

Methods

This cross-sectional study included data from 382 participants with SCI. The SII was calculated for all participants. Logistic regression, smooth curve fitting, interaction effects were used to substantiate the research objectives.

Results

The overall prevalence of DVT was 23.1% (22.4% among males, 25.6% among females). A positive association between SII and the risk for DVT was observed (odds ratio 1.39 [95% CI 1.03-1.87]; P=0.032), independent of confounders. Similar patterns of association were observed in the subgroup analysis (P values for interaction, all >0.05). Further sensitivity analyses provided confidence that the results were reliable and unlikely to be substantially altered by unmeasured confounding factors.

Conclusion

Results of the present suggest that higher SII may be associated with DVT in patients with SCI, highlighting a potential link between SII and DVT. These findings underscore the potential of SII as a valuable predictive biomarker for DVT, thus offering a promising avenue for early detection and intervention strategies in patients with SCI.

A rare HSC-derived megakaryocyte progenitor accumulates via enhanced survival and contributes to exacerbated thrombopoiesis upon aging

Distinct routes of cellular production from hematopoietic stem cells (HSCs) have defined our current view of hematopoiesis. Recently, we challenged classical views of platelet generation, demonstrating that megakaryocyte progenitors (MkPs), and ultimately platelets, can be specified via an alternate and additive route of HSC-direct specification specifically during aging. This "shortcut" pathway generates hyperactive platelets likely to contribute to age-related platelet-mediated morbidities. Here, we used single-cell RNA/CITEseq to demonstrate that these age-unique, non-canonical (nc)MkPs can be prospectively defined and experimentally isolated from wild type mice. Surprisingly, this revealed that a rare population of ncMkPs also exist in young mice. Young and aged ncMkPs are functionally distinct from their canonical (c)MkP counterparts, with aged ncMkPs paradoxically and uniquely exhibiting enhanced survival and platelet generation capacity. We further demonstrate that aged HSCs generate significantly more ncMkPs than their younger counterparts, yet this is accomplished without strict clonal restriction. Together, these findings reveal significant phenotypic, functional, and aging-dependent heterogeneity among the MkP pool and uncover unique features of megakaryopoiesis throughout life, potentially offering cellular and molecular targets for mitigation of age-related adverse thrombotic events.

Platelet count has a U-shaped association with mortality in hemodialysis patients

Our previous manuscript showed that thrombocytopenia predicts all-cause mortality in Chinese hemodialysis (HD) patients. Based on the role of platelets in coagulation, clot formation, and systemic inflammation, we speculate that high platelets increase risk of thrombo-embolic events, hence the mortality. However, research evidence is currently lacking. Therefore, we utilized data from a very large international cohort study to explore the association of platelet counts with mortality and cardiovascular (CV) death in hemodialysis (HD) patients. International data from 396 facilities enrolled in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 5 (2012-2015) were analyzed. Participants were divided into 3 groups according to their platelet counts (low: <100, normal: 100-300, high: >300*109). Associations between platelet counts and all-cause and CV mortality were analyzed using Cox regression, adjusted for confounders. There were 13,631 patients with median age of 65 years old. Males accounted for 61.2%. Mean platelet count was 205*109/L overall and ranged from 173 *109/L in China to 227 *109/L in Sweden. Overall, 2,348 (17.2%) patients died and 1017 (7.5%) died from CV disease. Both low (HR:1.48, 95% CI 1.21-1.80, p < 0.001) and high (HR:1.17, 95% CI 1.00- 1.35, p = 0.044) platelet counts were associated with higher all-cause mortality after adjustment for covariates; results for CV death were consistent. Platelet count has a U-shaped association with all-cause and CV mortality in HD patients, and thus may be used as an outcome predictor that is readily available among HD patients.

Hyperexpression of PTAFR and PF4 as Possible Platelet Risk Biomarkers in Patients With COVID-19

BACKGROUND/AIM

SARS-CoV-2 infection presents different severity levels that suggest the influence of genetic factors on the clinical outcome of the disease. In cases of severe COVID-19, the presence of elevated coagulation markers, increased platelet activation and aggregation and the risk of thrombotic complications are described. Given the participation of these cells in several serious viral infections and their negative role when associated with a prothrombotic response, it is important to understand the mechanistic role of SARS-CoV-2 in platelet physiology. This study evaluated the hyperexpression of platelet-activating factor receptor (PTAFR) and platelet factor 4 (PF4) in unvaccinated and hospitalized patients with COVID-19.

PATIENTS AND METHODS

The study included 43 COVID-19 patients stratified according to WHO guidelines. Subsequently, the expression of the PTAFR and PF4 genes were evaluated using the real-time quantitative PCR and their possible correlation with the severity of the disease and clinical variables including hospitalization, outcome, sex, age and laboratory parameters (platelet count, INR and D-dimer).

RESULTS

The analysis demonstrated a significant (p<0.05) hyperexpression of these genes COVID-19 patients (n=43) compared to healthy controls. Expression of these genes in patients was not statistically significant (p>0.05) different between patients stratified according to clinical variables.

CONCLUSION

The expression of PTAFR and PF4 suggests an important molecular pathway in the pathophysiology of the disease and may be valuable platelet biomarkers to indicate increased risk in patients with COVID-19 who require hospital care, contributing to personalized intervention strategies and improving their clinical management.

The roles of migrasomes in immunity, barriers, and diseases

Migrasomes are recently identified extracellular vesicles and organelles formed in conjunction with cell migration. They are situated at the rear of migrating cells, exhibit a circular or elliptical membrane-enclosed structure, and function as a new organelle. Migrasomes selectively sort intercellular components, mediating a cell migration-dependent release mechanism known as migracytosis and modulating cell-cell communication. Accumulated evidence clarifies migrasome formation processes and indicates their diverse functional roles. Migrasomes may also be potentially correlated with the occurrence, progression, and prognosis of certain diseases. Migrasomes' involvement in physiological and pathological processes highlights their potential for expanding our understanding of biological procedures and as a target in clinical therapy. However, the precise mechanisms and full extent of their involvement in immunity, barriers, and diseases remain unclear. This review aimed to provide a comprehensive overview of the roles of migrasomes in human immunity and barriers, in addition to providing insights into their impact on human diseases. STATEMENT OF SIGNIFICANCE: Migrasomes, newly identified extracellular vesicles and organelles, form during cell migration and are located at the rear of migrating cells. These circular or elliptical structures mediate migracytosis, selectively sorting intercellular components and modulating cell-cell communication. Evidence suggests diverse functional roles for migrasomes, including potential links to disease occurrence, progression, and prognosis. Their involvement in physiological and pathological processes highlights their significance in understanding biological procedures and potential clinical therapies. However, their exact mechanisms in immunity, barriers, and diseases remain unclear. This review provides an overview of migrasomes' roles in human immunity and barriers, and their impact on diseases.

Correlation and predictive value of platelet biological indicators and recurrence of large-artery atherosclerosis type of ischemic stroke

Large-artery atherosclerosis type of ischemic stroke happens when a blood clot forms in a major artery that carries blood to the brain. This causes a blockage and a decrease in blood flow to the brain tissue making up approximately 15-20% of all cases. This type of stroke is more prevalent in older adults and those with risk factors such as high blood pressure, high cholesterol, diabetes, smoking, and a family history of stroke. To investigate the correlation and predictive value of platelet-related biological indicators with recurrence of large-artery atherosclerosis type of ischemic stroke (LAA-IS)2. The patients were divided into a relapse group (R, n = 40) and non-relapse group (NR, n = 45). Platelet-related biological indicators were collected from both groups to analyze their correlation with neurological impairment score (NIHSS score). Risk factors were analyzed using binary logistic regression and a survival curve (ROC) was drawn to evaluate the predictive effect of clinical platelet-related biological indicators on LAA-IS recurrence. This study confirmed that PAg-ADP, PAg-COL, and FIB are closely related to the formation of LAA-IS due to carotid atherosclerosis, and the combined PAg-ADP, PAg-COL, and FIB index levels are the most promising for assessing the prognostic development of recurrence in patients with LAA-IS. Combined monitoring of platelet aggregation rate and FIB index is of important evaluation value in judging the recurrence prognosis of LAA-IS patients.

Systemic C-Reactive Protein Predicts Cerebral Vasospasm and Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage: A Retrospective Observational Study

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is often complicated by cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI), which significantly impact patient outcomes. The study aimed to investigate the predictive value of systemic serum biomarker levels for CVS and DCI following aSAH.

METHODS

We retrospectively analyzed data for 450 aSAH patients admitted to University Hospital Düsseldorf between January 2011 and October 2021. Serum biomarkers were measured on admission. The occurrence of CVS and DCI was assessed based on clinical and radiological criteria. Multivariate logistic regression analysis was performed to determine the independent association of serum biomarkers with CVS and DCI. We compared the predictive values of various models using the area under the receiver operating characteristic curve.

RESULTS

Of the 450 patients, 126 (28.0%) developed CVS, 123 (27.3%) developed DCI, and 62 (13.8%) developed co-occurring CVS and DCI. Patients with CVS, DCI, or both had significantly higher admission C-reactive protein (CRP) levels than those without these complications (P < 0.001). Elevated CRP levels were independently associated with an increased risk of CVS, DCI, and co-occurring CVS and DCI (P < 0.05). CRP demonstrated a higher predictive value for CVS (area under the curve [AUC]: 0.811) and co-occurring CVS and DCI (AUC: 0.802) compared to DCI alone (AUC: 0.690).

CONCLUSIONS

Our findings suggest that admission systemic CRP levels can serve as a more valuable predictor for developing CVS than DCI following aSAH. Incorporating CRP into clinical assessments may aid in risk stratification and early intervention strategies for patients at high risk of these complications.

Association between inflammation-related indicators and vertebral fracture in older adults in the United States: A cross-sectional study based on National Health and Nutrition Examination Survey 2013-2014

OBJECTIVE

This study was to examine the association between inflammation-related indexes SII (systemic immune-inflammation index), NLR (neutrophil-to-lymphocyte ratio), PPN (product of platelet count and neutrophil count), and PLR (platelet-to-lymphocyte ratio), and the occurrence of vertebral fractures in older Americans.

METHODS

Patients ⩾60 years of age from the 2013-2014 NHANES database were selected for this study. Restricted cubic spline models and weighted logistic regression models were used to assess the association between inflammation-related indexes and the occurrence of vertebral fractures in older Americans. The predictive value of the inflammation-related indexes on the occurrence of vertebral fractures was assessed using receiver operating characteristic curves (ROC). To examine the robustness of the main findings, a sensitivity analysis was conducted.

RESULTS

A total of 1281 patients were included in the analysis, of whole 120 suffered vertebral fractures. Fully adjusted logistic regression showed a significant linear relationship between NLR and the occurrence of vertebral fracture in older Americans (p < .05), but no relationship was found between SII, PLR, and the occurrence of vertebral fracture in older Americans. Meanwhile, NLR was slightly better than other indicators in predicting vertebral fracture.

CONCLUSIONS

This study found that NLR, as a novel inflammatory marker, can predict the risk of vertebral fracture in older Americans, which is of clinical significance for the prevention and treatment of vertebral fracture in older adults.

Functional Foods in Preventing Human Blood Platelet Hyperactivity-Mediated Diseases-An Updated Review

Backgrounds/Objectives: Abnormal platelet functions are associated with human morbidity and mortality. Platelets have emerged as critical regulators of numerous physiological and pathological processes beyond their established roles in hemostasis and thrombosis. Maintaining physiological platelet function is essential to hemostasis and preventing platelet-associated diseases such as cardiovascular disease, cancer metastasis, immune disorders, hypertension, diabetes, sickle cell disease, inflammatory bowel disease, sepsis, rheumatoid arthritis, myeloproliferative disease, and Alzheimer's disease. Platelets become hyperactive in obesity, diabetes, a sedentary lifestyle, hypertension, pollution, and smokers. Platelets, upon activation, can trawl leukocytes and progenitor cells to the vascular sites. Platelets release various proinflammatory, anti-inflammatory, and angiogenic factors and shed microparticles in the circulation, thus promoting pathological reactions. These platelet-released factors also maintain sustained activation, further impacting these disease processes. Although the mechanisms are unknown, multiple stimuli induce platelet hyperreactivity but involve the early pathways of platelet activation. The exact mechanisms of how hyperactive platelets contribute to these diseases are still unclear, and antiplatelet strategies are inevitable for preventing these diseases. Reducing platelet function during the early stages could significantly impact these diseases. However, while this is potentially a worthwhile intervention, using antiplatelet drugs to limit platelet function in apparently healthy individuals without cardiovascular disease is not recommended due to the increased risk of internal bleeding, resistance, and other side effects. The challenge for therapeutic intervention in these diseases is identifying factors that preferentially block specific targets involved in platelets' complex contribution to these diseases while leaving their hemostatic function at least partially intact. Since antiplatelet drugs such as aspirin are not recommended as primary preventives, it is essential to use alternative safe platelet inhibitors without side effects.

METHODS

A systematic search of the PUBMED database from 2000 to 2023 was conducted using the selected keywords: "functional foods", "polyphenols", "fatty acids", "herbs", fruits and vegetables", "cardioprotective agents", "plant", "platelet aggregation", "platelet activation", "clinical and non-clinical trial", "randomized", and "controlled".

RESULTS

Potent natural antiplatelet factors have been described, including omega-3 fatty acids, polyphenols, and other phytochemicals. Antiplatelet bioactive compounds in food that can prevent platelet hyperactivity and thus may prevent several platelet-mediated diseases, including cardiovascular disease.

CONCLUSIONS

This narrative review describes the work during 2000-2023 in developing functional foods from natural sources with antiplatelet effects.

Phillyrin and its metabolites treat pulmonary embolism by targeting PLCβ3 to inhibit platelet activation

ETHNOPHARMACOLOGICAL RELEVANCE

Lian Qiao (LQ), the dried fruit of Forsythia suspensa (Thunb.) Vahl, is a well-documented traditional Chinese medicine known for its detoxifying and heat-clearing properties. Clinically, compounds containing LQ are widely used to treat thrombotic diseases, indicating that it may have antithrombotic effects. However, its exact mechanism of action remains unknown.

AIM OF THE STUDY

This study aimed to verify the antithrombotic effect of LQ and further explore the material basis and target mechanism of its antithrombotic effect using various biological methods.

MATERIALS AND METHODS

An epinephrine-collagen-thrombin-induced mouse model of acute pulmonary embolism (APE) was established to study the effects of LQ on thrombus development. A UPLC/Q/TOF-MS screening and identification system based on the inhibition of platelet aggregation and Ca2+ antagonism was established to determine the pharmacodynamic components of LQ that inhibit platelet activation. The inhibitory effect of active ingredients on platelet activation, and the determination of the target of their inhibitory effect on platelet activation have been studied using chemical proteomics. Furthermore, based on the structure and function of the target protein, a multidisciplinary approach was adopted to analyze the molecular mechanism of active ingredient binding to target proteins and to evaluate the effects of active ingredients on the downstream signaling pathways of target proteins.

RESULTS

LQ showed significant anticoagulant effects in APE model mice. Phillyrin and phillygenin were the antiplatelet-activating components of LQ. PLCβ3 was identified as a target for inhibiting platelet activation by phillyrin and its metabolites. The mechanism underlying the effect involves phillyrin and its metabolites inhibiting PLCβ3 activity by blocking the binding of PLCβ3 to Gαq through non-covalently targeting the ASN260 of PLCβ3, thus inhibiting the downstream Gαq-PLCβ3-Ca2+ signaling pathway, effectively hindering platelet activation and therefore playing an anticoagulant role.

CONCLUSION

This study not only proposes and validates the antithrombotic effect of LQ for the first time but also finds that phillyrin and phillygenin are the main pharmacological substances through which LQ exerts antithrombotic activity and reveals a novel mechanism by which they exert antiplatelet activity by directly targeting and inhibiting PLCβ3 activity. These findings significantly contribute to our understanding of the therapeutic potential of phillyrin and provide important clues for the discovery and development of new antiplatelet drugs.

Potential Predictive Value of Platelet Distribution Width for Functional Outcome After Ischemic Stroke

Complete blood cell count (CBC) is the most common and readily available laboratory test in clinical practice. The relationships of some CBC indices with ischemic stroke have been reported in observational studies; however, the causal direction is not specified. This study aimed to explore the causal relationships between CBC indices and the modified Rankin Scale (mRS) score at 3 months after ischemic stroke. Genetic associations of 22 blood cell traits were obtained from the UK Biobank database (n = 350,475). The outcome data for ischemic stroke were obtained from the Genetic Ischemic Stroke Functional Outcome (GISCOME) network (n = 6021). We implemented two-sample Mendelian randomization (TSMR) and several complementary analyses to assess the causal association between blood traits and unfavorable outcome (3-month mRS > 2). The clinical cohort was validated based on the results of the MR analysis. TSMR result indicated causal association between genetically determined platelet distribution width (PDW) and adverse functional outcome after ischemic stroke (OR 1.48; 95% CI 1.13-1.95; p = 0.005). Complementary analyses showed negligible causal effect of genetic variants on stroke subtypes. In cohort study (n = 351), higher level of PDW was observed in the unfavorable outcome group. However, the multivariable logistic regression analysis failed to identify the improvement in predictive performance of stroke outcomes by adding PDW to the prediction model. Further correlation analysis revealed that PDW is positively correlated with serum glucose levels, and the level of PDW in the non-thrombolysed group was significantly higher than that in the thrombolysis group, indicating that PDW may be involved in stroke prognosis in an indirect way.

A Predictive Model for Disseminated Intravascular Coagulopathy in Sepsis: An Observational Study

Introduction

Sepsis remains a significant global health challenge due to its high morbidity and mortality rates. Disseminated Intravascular Coagulopathy (DIC) represents a critical complication of sepsis, contributing to increased mortality and economic burden. Despite various prognostic scoring systems, there is a lack of a specific model for DIC prediction in sepsis patients.

Methods

This observational study included 336 sepsis patients. Clinical and laboratory data were collected, and prognoses were defined according to established criteria.

Results

We enrolled 336 patients, with 304 in the non-DIC group and 32 in the DIC group. Patients with DIC had notably lower platelet (PLT) and higher levels of prothrombin time (PT), lactate (LAC), and procalcitonin (PCT) compared to those without DIC. Univariate and multivariate analyses identified risk factors associated with the DIC, showing that PLT (OR = 0.985, 95% CI 0.978-0.993, p < 0.001), PT level (OR = 1.140, 95% CI 1.004-1.295, p = 0.044), and LAC (OR = 1.101, 95% CI 0.989-1.226, p = 0.078) were related factors. A risk model was established, and its sensitivity and specificity in predicting DIC among sepsis patients were assessed by comparing it to the SOFA score. The area under the ROC curve for the model was 0.850, while the SOFA score was 0.813. With a model score >-2.12, the sensitivity for predicting DIC was 84.4%, and the specificity was 75.0%.

Conclusion

Our study introduces a predictive model for DIC detection in sepsis patients, emphasizing the need for clinicians to focus on patients with high model scores for timely intervention.

Unveiling inflammatory biomarkers in multibacillary leprosy: the role of lymphocyte-platelet ratio in predicting leprosy reactions

Leprosy is a neglected contagious disease that causes physical disability and episodes of inflammation, called leprosy reactions. There are currently no consolidated laboratory markers that can predict or confirm the diagnosis of leprosy reactions, negatively impacting the progression of the disease. The aim of this study was to analyze the behavior of inflammatory biomarkers in a population of patients with multibacillary leprosy. This prospective study in a northeastern capital involved 67 new cases of multibacillary leprosy, assessing inflammatory biomarkers at diagnosis. Histopathology, qPCR, slit skin smear microscopy, and laboratory tests, including CRP-albumin, neutrophil-lymphocyte, lymphocyte-monocyte, platelet-lymphocyte ratios, and systemic immune-inflammation index, were conducted. Statistical analysis utilized Stata version 16.0®, employing Chi-square, Kruskal-Wallis, and Poisson regression (5% significance). The population, mainly young brown men with low socioeconomic status, borderline leprosy, and and degree of physical disability one, saw 19.4% experiencing leprosy reactions. Standard multibacillary multidrug therapy was administered to all. Ratios and index values exceeding medians were prevalent (46.3-47.8%). Assessing biological markers against leprosy reactions revealed a positive relation between reactions and lymphocyte-platelet ratio (p = 0.05) and a positive trend with the systemic immune-inflammation index (p = 0.06). Patients with reactions were 1.3 times more likely to exhibit an elevated lymphocyte-platelet ratio. The lymphocyte-platelet ratio emerged as a potential indicator for recognizing leprosy reactions. Further research is essential to validate these findings, aiming for earlier detection of leprosy reactions.

Platelets camouflaged nanovehicle improved bladder cancer immunotherapy by triggering pyroptosis

The regulation of immunosuppressive microenvironments in tumors through targeted drug delivery shows promise for immunochemotherapy in bladder cancer. Drawing inspiration from stealth tactics, a nano-vehicle camouflaged with platelets (PLTs) was developed to enable precise delivery and trigger pyroptosis for tumor immunotherapy. Methods: Erdafitinib (Erda) was nano-sized and encapsulated in PLTs to construct nano-Erda@PLT. Characterization of the PLTs camouflaged nano-vehicle was conducted using Zetasizer, SEM, and confocal laser scanning microscopy. The excellent targeted delivery property of the PLTs nano-vehicle was investigated through intravital imaging, three-dimensional microspheres, and SEM. Validation of pyroptosis in bladder cancer cells via the caspase-3/GSDME pathway was performed using western blot, immunofluorescence, and ELISA tests. Immunotherapy by nano-Erda@PLT treatment in vivo was confirmed using H&E, immunohistochemical, and flow cytometry. Lastly, the side effects of nano-Erda@PLT were assessed. Results: Proteomic analysis revealed that the activation of p-selectin on platelets facilitated the identification of nano-Erda@PLT targeted therapies. Nanoscale of Erda released in response to adenosine diphosphate, facilitated intratumoral permeation. This could contribute to an upregulation of the key proteins of pyroptosis, caspase-3 and GSDME, in bladder cancer cells due to nano-Erda@PLT accumulation. Additionally, the burst release of numerous inflammatory factors may enhance the system's adaptive immune response. In a bladder cancer animal model, this treatment was found to regulate the immunosuppressive microenvironment, resulting in effective tumor immunotherapy and the induction of a long-lasting, robust immune memory. Conclusion: PLTs-camouflaged nano-vehicles enable nano-Erda-mediated tumor immunotherapy through the induction of pyroptosis. These findings introduce a novel approach in exploring nanomaterial-mediated pyroptosis for cancer immunotherapy.

Platelets isolation and ectonucleotidase assay: Revealing functional aspects of the communication between the vasculature and the immune system

Platelets are enucleated fragments of cells with a diversity of internal granules. They are responsible for functions related to hemostasis, coagulation, and inflammation. The activation of these processes depends on a cascade coordinated by cytokines, chemokines, and components of purinergic signaling, such as ATP, ADP, and adenosine. Platelets express distinct components of the purinergic system: P2X1, P2Y1, PY12, and P2Y14 receptors; and the ectonucleotidases NTPDase, NPP, and 5NTE (ecto-5'-nucleotidase). Except for P2Y14, which has not yet exhibited a known function, all other components relate to the biological processes mentioned before. Platelets are known to display specific responses to microorganisms, being capable of recognizing pathogen-associated molecular patterns (PAMPs), engulfing certain classes of viruses, and participating in NETosis. Platelet function dysregulation implicates various pathophysiological processes, including cardiovascular diseases (CVDs) and infections. In COVID-19 patients, platelets exhibit altered purinergic signaling and increased activation, contributing to inflammation. Excessive platelet activation can lead to complications from thrombosis, which can affect the circulation of vital organs. Therefore, controlling the activation is necessary to end the inflammatory process and restore homeostasis. Ectonucleotidases, capable of hydrolyzing ATP, ADP, and AMP, are of fundamental importance in activating platelets, promising pharmacological targets for clinical use as cardiovascular protective drugs. In this review, we revisit platelet biology, the purinergic receptors and ectonucleotidases on their surface, and their importance in platelet activity. Additionally, we describe methods for isolating platelets in humans and murine, as well as the main techniques for detecting the activity of ectonucleotidases in platelets. Considering the multitude of functions revealed by platelets and their potential use as potent bioreactors able to secrete and present molecules involved in the communication of the vasculature with the immune system, it is crucial to deeply understand platelet biology and purinergic signaling participation to contribute to the developing of therapeutic strategies in diseases of the cardiovascular, inflammatory, and immune systems.

Association between Systemic Immune-Inflammation Index (SII) and New-Onset In-Hospital Heart Failure in Patients with STEMI after Primary PCI

Background

The systemic immune-inflammation index (SII) is a proven, reliable inflammatory marker of the atherosclerotic process. Additionally, inflammation is one of the most important mechanisms of heart failure (HF) after myocardial infarction (MI). However, it is not clear whether SII is related to the risk of in-hospital HF in patients with MI. Thus, we aimed to explore the relationship between SII and the risk of new-onset in-hospital HF in ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (pPCI).

Methods

A total of 5586 patients with STEMI underwent pPCI at seven clinical sites in China from January 2015 to August 2021. The patients were divided into two groups based on the SII values. The association between SII and new-onset in-hospital HF in STEMI patients was assessed using logistic regression analysis.

Results

Ultimately, 3808 STEMI patients with Killip class I who were treated with pPCI were included. All included patients were divided into two groups based on the calculated SII (Q1 SII: <1707.31 (×109/L), Q2 SII: ≥1707.31 (×109/L)). After unadjusted and multivariate adjustment for age, gender, vital signs, smoking, hypertension, diabetes mellitus, etc., the odds ratio (OR) of the in-hospital HF risk in Q2 was 1.378-1.427 times the Q1 in the calibration Models 1 to 5. Subgroup analysis showed that the OR of Q2 was 1.505-fold higher of Q1 in males and 1.525-fold in older people (≥60 years). Sensitivity analysis showed that after excluding patients who had previously experienced HF, MI, or underwent PCI, elevated SII was still associated with a significant increase in the risk of in-hospital HF.

Conclusions

Elevated SII is associated with an increased risk of in-hospital HF in STEMI patients treated with pPCI, particularly in male and older patients.

Clinical Trial Registration

The Chinese STEMI pPCI Registry was registered with ClinicalTrials.gov (NCT04996901, https://www.clinicaltrials.gov/study/NCT04996901?cond=NCT04996901&rank=1).

Platelet dysfunction caused by differentially expressed genes as key pathogenic mechanisms in COVID-19

At the end of 2019, the novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became prevalent worldwide, which brought a heavy medical burden and tremendous economic losses to the world population. In addition to the common clinical respiratory symptoms such as fever, cough and headache, patients with COVID-19 often have hematological diseases, especially platelet dysfunction. Platelet dysfunction usually leads to multiple organ dysfunction, which is closely related to patient severity or mortality. In addition, studies have confirmed significant changes in the gene expression profile of circulating platelets under SARS-CoV-2 infection, which will further lead to changes in platelet function. At the same time, studies have shown that platelets may absorb SARS-COV-2 mRNA independently of ACE2, which further emphasizes the importance of the stability of platelet function in defense against SARS-CoV-2 infection. This study reviewed the relationship between COVID-19 and platelet and SARS-CoV-2 damage to the circulatory system, and further analyzed the significantly differentially expressed mRNA in platelets after infection with SARS-CoV-2 on the basis of previous studies. The top eight hub genes were identified as NLRP3, MT-CO1, CD86, ICAM1, MT-CYB, CASP8, CXCL8 and CXCR4. Subsequently, the effects of SARS-CoV-2 infection on platelet transcript abnormalities and platelet dysfunction were further explored on the basis of 8 hub genes. Finally, the treatment measures of complications caused by platelet dysfunction in patients with COVID-19 were discussed in detail, so as to provide reference for the prevention, diagnosis and treatment of COVID-19.

Development and Validation of a Prediction Model for Thyroid Dysfunction in Patients During Immunotherapy

OBJECTIVE

This study was designed to develop and validate a predictive model for assessing the risk of thyroid toxicity following treatment with immune checkpoint inhibitors.

METHODS

A retrospective analysis was conducted on a cohort of 586 patients diagnosed with malignant tumors who received programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors. The patients were randomly divided into training and validation cohorts in a 7:3 ratio. Logistic regression analyses were performed on the training set to identify risk factors of thyroid dysfunction, and a nomogram was developed based on these findings. Internal validation was performed using K-fold cross-validation on the validation set. The performance of the nomogram was assessed in terms of discrimination and calibration. Additionally, decision curve analysis was utilized to demonstrate the decision efficiency of the model.

RESULTS

Our clinical prediction model consisted of 4 independent predictors of thyroid immune-related adverse events, namely baseline thyrotropin (TSH, OR = 1.427, 95%CI:1.163-1.876), baseline thyroglobulin antibody (TgAb, OR = 1.105, 95%CI:1.035-1.180), baseline thyroid peroxidase antibody (TPOAb, OR = 1.172, 95%CI:1.110-1.237), and baseline platelet count (platelet, OR = 1.004, 95%CI:1.000-1.007). The developed nomogram achieved excellent discrimination with an area under the curve of 0.863 (95%CI: 0.817-0.909) and 0.885 (95%CI: 0.827-0.944) in the training and internal validation cohorts respectively. Calibration curves exhibited a good fit, and the decision curve indicated favorable clinical benefits.

CONCLUSION

The proposed nomogram serves as an effective and intuitive tool for predicting the risk of thyroid immune-related adverse events, facilitating clinicians making individualized decisions based on patient-specific information.

Dynamic perioperative platelet activity and cardiovascular events in peripheral artery disease

OBJECTIVE

Patients with peripheral artery disease (PAD) undergo lower extremity revascularization (LER) for symptomatic relief or limb salvage. Despite LER, patients remain at increased risk of platelet-mediated complications, such as major adverse cardiac and limb events (MACLEs). Platelet activity is associated with cardiovascular events, yet little is known about the dynamic nature of platelet activity over time. We, therefore, investigated the change in platelet activity over time and its association with long-term cardiovascular risk.

METHODS

Patients with PAD undergoing LER were enrolled into the multicenter, prospective Platelet Activity and Cardiovascular Events study. Platelet aggregation was assessed by light transmission aggregometry to submaximal epinephrine (0.4 μmol/L) immediately before LER, and on postoperative day 1 or 2 (POD1 or POD2) and 30 (POD30). A hyperreactive platelet phenotype was defined as >60% aggregation. Patients were followed longitudinally for MACLEs, defined as the composite of death, myocardial infarction, stroke, major lower extremity amputation, or acute limb ischemia leading to reintervention.

RESULTS

Among 287 patients undergoing LER, the mean age was 70 ± 11 years, 33% were female, 61% were White, and 89% were on baseline antiplatelet therapy. Platelet aggregation to submaximal epinephrine induced a bimodal response; 15.5%, 16.8%, and 16.4% of patients demonstrated a hyperreactive platelet phenotype at baseline, POD1, and POD30, respectively. Platelet aggregation increased by 18.5% (P = .001) from baseline to POD1, which subsequently returned to baseline at POD30. After a median follow-up of 19 months, MACLEs occurred in 165 patients (57%). After adjustment for demographics, clinical risk factors, procedure type, and antiplatelet therapy, platelet hyperreactivity at POD1 was associated with a significant hazard of long-term MACLE (adjusted hazard ratio, 4.61; 95% confidence interval, 2.08-10.20; P < .001).

CONCLUSIONS

Among patients with severe PAD, platelet activity increases after LER. Platelet hyperreactivity to submaximal epinephrine on POD1 is associated with long-term MACLE. Platelet activity after LER may represent a modifiable biomarker associated with excess cardiovascular risk.

Relation between peripheral blood inflammatory indices and severity of central retinal artery occlusion

Background

Central retinal artery occlusion (CRAO) has been identified as an acute emergency resulting in vision loss, with its pathogenesis potentially involving systemic inflammation and abnormal lipid metabolism. Over recent years, it has been established that peripheral blood inflammatory indices, including the neutrophil-to-lymphocyte ratio (NLR), the systemic immunoinflammatory index (SII), and the monocyte-to-high-density lipoprotein ratio (MHR), play significant roles in assessing systemic inflammation and lipid metabolism. However, the role of these indices in assessing the severity of CRAO has rarely been explored. This study aimd to investigate the relationship between these inflammatory indices and the severity of CRAO.

Methods

This was a retrospective clinical study with a total of 49 CRAO patients and 50 age- and sex-matched controls involved. The patients with CRAO were divided into three groups (13 with incomplete CRAO, 16 with subtotal CRAO and 20 with total CRAO). Data were compared across these groups, and additionally, correlation analysis, restricted cubic spline plots, and receiver operating characteristic curve analysis were performed.

Results

The values of NLR, SII and MHR were significantly higher in the CRAO group compared to controls (NLR: 2.49(1.71,3.44) vs 1.60(1.24,1.97), P<0.001; SII: 606.46(410.25,864.35) vs 403.91(332.90,524.31), P=0.001; MHR: 0.33(0.26,0.44) vs 0.25(0.21,0.34), P<0.001). MHR was also significantly higher in total CRAO than in incomplete CRAO and subtotal CRAO (0.41(0.32,0.60) vs 0.29(0.21,0.43), P=0.036; 0.41(0.32,0.60) vs 0.29(0.23,0.38), P=0.017). Significant positive associations were found between MHR, NLR, SII and both the incidence (all P<0.001) and severity (P<0.001, P<0.001, P=0.003, respectively) of CRAO. MHR had a linear relationship with both the occurrence and severity of CRAO (P-overall=0.013, P-non-linear=0.427 and P-overall=0.013, P-non-linear=0.825). Combining MHR and NLR significantly improved diagnostic efficacy for CRAO and total CRAO, with area under the curve of 0.816 and 0.827, respectively, compared to using MHR alone (0.705 and 0.816).

Conclusion

Elevated levels of peripheral blood NLR, SII, and MHR are positively associated with CRAO incidence, highlighting their potential as early predictive markers. The combined NLR and MHR index further enhances diagnostic accuracy and may facilitate timely assessment of CRAO severity by ophthalmologists and internists.

Platelet count has a nonlinear association with 30-day in-hospital mortality in ICU end-stage kidney disease patients: a multicenter retrospective cohort study

This study addresses the relationship between platelet count and 30-day in-hospital mortality in End-Stage Kidney Disease (ESRD) patients in the intensive care unit (ICU), a topic with limited existing evidence. Utilizing data from the US eICU-CRD v2.0 database (2014-2015), a retrospective cohort study was conducted involving 3700 ICU ESRD patients. We employed binary logistic regression, smooth curve fitting, and subgroup analyses to explore the association between platelet count and 30-day in-hospital mortality. The 30-day in-hospital mortality rate was 13.27% (491/3700), with a median platelet count of 188 × 109/L. After adjusting for covariates, we observed a relationship between platelet count and 30-day in-hospital mortality (OR = 0.98, 95% CI 0.97, 0.99). Subgroup analyses supported these findings. More importantly, a nonlinear association was detected, with an inflection point at 222 × 109/L. The effect sizes (OR) on the left and right sides of the inflection point were 0.94 (0.92, 0.96) and 1.03 (1.00, 1.05), respectively. The most significant finding of this study is the revelation of a nonlinear relationship between baseline platelet count and 30-day in-hospital mortality in ICU patients with ESRD. This discovery explicitly suggests that when ESRD patients are admitted to the ICU, a platelet level closer to 222 × 10⁹/L may predict a lower 30-day in-hospital mortality risk.

Exploring the effect of hydroxyapatite nanoparticle shape on red blood cells and blood coagulation

Aim: In this study, we evaluated the effects of two types of hydroxyapatite (HAP) nanoparticles, sharing the same surface chemistry but differing in shape, on the biological characteristics of plasma, platelets and red blood cells.Materials & methods: Initially, two different shapes (rod-shaped and sphere-shaped) of HAPs were characterized. These HAPs were then co-cultured with plasma and red blood cells to examine their impact on coagulation and hemolysis. The impact of HAPs on white blood cells count in mice were evaluated following gavage and tail vein injection.Results: Sphere-shaped HAP is more likely to adsorb onto platelet surfaces, while rod-shaped HAP is more likely to cause hemolysis. Although there are differences in the in vitro experimental results between sphere-shaped HAP and rod-shaped HAP, both types demonstrate good blood compatibility at a 20 mM concentration. Furthermore, in vivo experiments showed that sphere-shaped nano-HAP induced a more pronounced increase in white blood cell count, suggesting that it may exhibit greater toxicity.Conclusion: While differences exist in the blood compatibility test results between the two HAPs, these differences are minimal, with both results falling within a safe range. Overall, HAP demonstrates excellent blood compatibility.

Blood cell traits and venous thromboembolism in East Asians: Observational and genetic evidence

Previous studies have indicated that various blood cell traits are associated with a higher risk of venous thromboembolism (VTE). However, the causal relationship remains uncertain. We collected data from the China pulmonary thromboembolism registry study and the China pulmonary health study, using propensity score matching and two-sample Mendelian randomization analyses with summary statistics from genome-wide association studies of blood cell traits and VTE in the East Asian population. Our findings revealed that platelet (PLT) count and hemoglobin (Hb) levels were significantly higher in VTE patients compared to the general population (p value <0.01). Genetically predicted Hb levels were positively associated with VTE, with an odds ratio (OR) of 2.38 (1.13-5.01), p value = 0.022. Similarly, genetically predicted PLT count was positively correlated with VTE, with an OR of 1.33 (1.02-1.74), p value = 0.038. These results suggest a causal relationship and potential targets for prevention.

Shear Stress Promotes Remodeling of Platelet Glycosylation via Upregulation of Platelet Glycosidase Activity: One More Thing

BACKGROUND

 Mechanical circulatory support (MCS) is a mainstay of therapy for advanced and end-stage heart failure. Accompanied by systemic anticoagulation, contemporary MCS has become less thrombogenic, with bleeding complications emerging as a major cause of readmission and 1-year mortality. Shear-mediated platelet dysfunction and thrombocytopenia of undefined etiology are primary drivers of MCS-related bleeding. Recently, it has been demonstrated that deprivation of platelet surface glycosylation is associated with the decline of hemostatic function, microvesiculation, and premature apoptosis. We test the hypothesis that shear stress induces remodeling of platelet surface glycosylation via upregulation of glycosidase activity, thus facilitating platelet count decline and intense microvesiculation.

METHODS

 Human gel-filtered platelets were exposed to continuous shear stress in vitro. Platelets and platelet-derived microparticles (PDMPs) were quantified via flow cytometry using size standard fluorescent nanobeads. Platelet surface glycosylation and NEU1 expression were evaluated using lectin- or immune-staining and multicolor flow cytometry; lectin blotting was utilized to verify glycosylation of individual glycoproteins. Platelet neuraminidase, galactosidase, hexosaminidase, and mannosidase activities were quantified using 4-methylumbelliferone-based fluorogenic substrates.

RESULTS

 We demonstrate that shear stress promotes selective remodeling of platelet glycosylation via downregulation of 2,6-sialylation, terminal galactose, and mannose, while 2,3-sialylation remains largely unchanged. Shear-mediated deglycosylation is partially attenuated by neuraminidase inhibitors, strongly suggesting the involvement of platelet neuraminidase in observed phenomena. Shear stress increases platelet NEU1 surface expression and potentiates generation of numerous NEU1+ PDMPs. Platelets exhibit high basal hexosaminidase and mannosidase activities; basal activities of platelet neuraminidase and galactosidase are rather low and are significantly upregulated by shear stress. Shear stress of increased magnitude and duration promotes an incremental decline of platelet count and immense microvesiculation, both being further exacerbated by neuraminidase and partially attenuated by neuraminidase inhibition.

CONCLUSION

 Our data indicate that shear stress accumulation, consistent with supraphysiologic conditions of device-supported circulation, promotes remodeling of platelet glycosylation via selective upregulation of platelet glycosidase activity. Shear-mediated platelet deglycosylation is associated with platelet count drop and increased microvesiculation, thus offering a direct link between deglycosylation and thrombocytopenia observed in device-supported patients. Based on our findings, we propose a panel of molecular markers to be used for reliable detection of shear-mediated platelet deglycosylation in MCS.