Platelet Signaling and Disease: Targeted Therapy for Thrombosis and Other Related Diseases

Systemic coagulation-inflammation index in the prediction of ISR in patients undergoing drug-eluting stents implant: A retrospective study based on multiple machine learning methods

BACKGROUND

The Systemic Coagulation-Inflammation index (SCI) is an innovative hematological metric that accurately reflects both coagulopathic and inflammatory dynamics. In this paper, the objective of this paper is to explain the prognostic impact of SCI on ISR in patients with coronary heart disease (CAD).

METHODS

This retrospective study analyzed clinical data from 724 CAD patients who underwent PCI with DES between September 2017 and June 2023. The study compared preoperative clinical data between patients who developed ISR and non-ISR groups. To avoid overfitting, we implemented 5 folds of resampling prior to model development. We then divided the dataset into training and validation sets in a 7:3 ratio. We constructed eight different machine-learning models to predict the occurrence of ISR. We selected the optimal model based on its performance metrics and clinical net benefit, and further validated its predictive power using an independent external dataset. To interpret the results, we applied the Shapley Additive Explanation (SHAP) method to the final model, XgBoost, enabling a visual analysis of key predictors influencing ISR. Additionally, this paper externally validated the optimal model using data from Zhongnan Hospital of Wuhan University and plotted the corresponding working curves of the subjects. This approach offered robust and interpretable insights into factors related to ISR.

RESULTS

Significant differences in clinical characteristics were observed between the non-ISR and ISR groups. The internal validation results identified the Xgboost model as the optimal model due to its best performance (AUC = 0.971, 95 % CI 0.9569-0.9851) and favorable goodness-of-fit. Among the 10 predictive variables, sex, age, and SCI were strong predictors of ISR. Specifically, being male, increasing age, having a low SCI, a high Gensini score, and smoking habits were positively correlated with an increased risk of ISR. We validated the optimal model using external data from the Zhongnan Hospital of Wuhan University, which produced an excellent subject-worker curve with an area under the curve of 0.92.

CONCLUSION

In this paper, we have identified the Xgboost model as the optimal model for predicting ISR. In addition, sex, age, Gensini score, and smoking habits were strong predictors of ISR.

Palmitoylation in cardiovascular diseases: Molecular mechanism and therapeutic potential

Cardiovascular disease is one of the leading causes of mortality worldwide, and involves complex pathophysiological mechanisms that encompass various biological processes and molecular pathways. Post-translational modifications of proteins play crucial roles in the occurrence and progression of cardiovascular diseases, among which palmitoylation is particularly important. Various proteins associated with cardiovascular diseases can be palmitoylated to enhance the hydrophobicity of their molecular subdomains. This lipidation can significantly affect some pathophysiological processes, such as metabolism, inflammation by altering protein stability, localization, and signal transduction. In this review, we narratively summarize recent advances in the palmitoylation of proteins related to cardiovascular diseases and discuss its potential as a therapeutic target.

The EPA oxylipin, 12-HEPE, directly regulates human platelet activity

Arterial thrombosis, driven by platelet hyperactivity, is the underlying pathophysiology of most major cardiovascular events. Dietary fish oil supplementation containing ω-3 polyunsaturated fatty acids (PUFAs) elicits cardiovascular protection in at-risk patients. Studies have attributed the cardiovascular benefits of ω-3 PUFAs to eicosapentaenoic acid (EPA), the primary ω-3 PUFA present in fish oil supplements. However, the role of EPA in platelet activation remains unclear. This study aimed to evaluate whether the cardiovascular protection observed in individuals taking dietary supplements containing EPA is achieved by altering platelet function. Additionally, we investigated whether these effects are mediated through the 12-lipoxygenase (12-LOX)-derived oxidized lipid (oxylipin) metabolite of EPA, 12(S)-hydroxy-5Z,8Z,10E,14Z,17Z-eicosapentaenoic acid (12-HEPE). Human whole blood, platelet rich plasma, and washed platelets were treated with EPA or 12-HEPE, to assess their ability to regulate platelet activity. Both EPA and 12-HEPE inhibited agonist-stimulated platelet aggregation, and 12-HEPE was found to be the primary oxylipin produced by platelets in the presence of EPA. Furthermore, 12-HEPE more potently attenuated dense granule secretion, α-granule secretion, and integrin αIIbβ3 activation, in comparison to EPA. Interestingly, while EPA delayed thrombin-induced clot retraction and reduced platelet adhesion under flow, 12-HEPE did not affect these processes. Both EPA and 12-HEPE attenuated ex vivo thrombus formation; however, the same inhibitory concentrations did not alter coagulation parameters in thromboelastography. This study demonstrates EPA and its 12-LOX metabolite, 12-HEPE, effectively inhibit platelet activation. These findings suggest the antiplatelet effects of EPA are regulated, in part, through 12-HEPE, advancing our understanding of the cardiovascular benefits of EPA.

Mesoporous Silica Nanotraps for Mitigating Bleeding Risk From 'Irreversible' Antiplatelet Drugs

The severe bleeding complications of long-term antiplatelet therapy limit its broader application in the treatment or prevention of thrombosis-associated diseases. This risk is particularly serious when facing emergency surgeries where rapid restoration of normal platelet function is required. Timely reversal of the effects of antiplatelet agents becomes crucial in such scenarios. Despite the widespread use of clopidogrel and prasugrel for their potent antiplatelet activity, the absence of specific and effective reversal agents remains a notable challenge. The pharmacological activity of clopidogrel and prasugrel is mediated by sulfhydryl-containing active metabolites, which form disulfide bonds with P2Y12 receptors on the surface of platelets to inhibit their aggregation. Taking advantage of this action mechanism of these "irreversible" antiplatelet drugs, click chemistry-functionalized mesoporous silica (SiO2-Mal) nanotraps are fabricated to capture the antiplatelet drugs' active metabolites and restore hemostasis. Subsequently, a comprehensive assessment of the effectiveness and safety of the SiO2-Mal nanotraps is conducted using mouse, rabbit, and pig animal models, highlighting their potential application as a functional reversal agent for clinically relevant thienopyridine antiplatelet drugs, believed until now to be irreversible in their inhibition of platelet activity.

Analysis of Platelet Morphological Parameters as Clinical Risk Stratification in Acute Coronary Syndrome

BACKGROUND

Platelet activation plays a central role in the pathogenesis of acute coronary syndrome (ACS). Platelet morphological parameters, including MPV, PDW, and P-LCR, are emerging as biomarkers for predicting the severity of ACS and prognosis.

AIMS

This study aims to assess the relationship between these parameters and coronary severity and to evaluate their predicting adverse outcomes.

METHODS

A total of 134 ACS patients and 50 healthy controls were included in this prospective observational study. Platelet morphological parameters (MPV, PDW, and P-LCR) were measured at admission, and coronary artery lesion severity was determined using the Gensini score from coronary angiography. Multivariate logistic regression analysis assessed the predictive value of these platelet parameters for adverse outcomes, and ROC curve analysis was used to evaluate their diagnostic performance.

RESULTS

MPV, PDW, and P-LCR were significantly higher in ACS patients compared to healthy controls (p < 0.001). A strong positive correlation was found between platelet parameters and the Gensini score (MPV: r = 0.778, PDW: r = 0.800, P-LCR: r = 0.761; p < 0.001). Multivariate logistic regression identified MPV (OR = 1.807, p < 0.001), PDW (OR = 1.700, p = 0.001), and P-LCR (OR = 1.287, p < 0.001) as independent predictors of advent prognosis. ROC curve analysis showed that the combined use of MPV, PDW, and P-LCR provided superior predictive accuracy (AUC = 0.927) compared to the individual parameters.

CONCLUSION

Elevated platelet morphological parameters are strongly associated with coronary artery lesion severity and serve as independent predictors of adverse outcomes in ACS patients. The combined assessment of MPV, PDW, and P-LCR enhances risk stratification, offering a valuable tool for guiding therapeutics and improving prognosis in management.

Dendrobium nobile lindl extract modulates integrin αIIbβ3-mediated signaling pathways to inhibit platelet activation and thrombosis

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl. (DNL) is a promising medicinal plant. It has the traditional medicinal effects of promoting blood circulation and resolving stasis, as well as regulating the meridians and collaterals.

AIM OF THE STUDY

We studyed how DNL extract was involved in platelet activation and thrombosis and used network pharmacology and molecular docking analysis to help clarify the underlying mechanisms.

MATERIALS AND METHODS

The effect of DNL extract on platelet aggregation and ATP release function was examined by aggregometer; The effect of DNL extract on the binding of PAC-1 and fibrinogen to integrin was determined by flow cytometry; The effect of DNL extract on "outside-in" platelet signals was detected by platelet adhesion, spreading and clot retraction; Key compounds and major targets of platelet interactions with DNL extract were analyzed by network pharmacology and molecular docking and verified against related pathway proteins by western blotting; The effect of DNL extract on thrombosis was tested by mesenteric artery embolism model.

RESULTS

DNL extract exhibited inhibition of platelet function and PAC-1 and fibrinogen binding to integrin αIIbβ3. In addition, it delayed FeCl3-induced mesenteric artery thrombosis without affecting the clotting time and the hemostatic time of tail in mice. The detection of platelet "inside-out" and "outside-in" signaling by Western blot further confirmed the inhibitory effect of DNL extract on platelet activation.

CONCLUSIONS

DNL extract may affect the thrombosis process by inhibiting platelet activation via inhibiting integrin αⅡbβ3-mediated bidirectional signaling pathway proteins.

The Role of Platelet Dysfunctions in the Pathogenesis of the Hemostatic-Coagulant System Imbalances

Platelet dysfunction plays a critical role in the pathogenesis of various disorders affecting the hemostatic-coagulant system. This review aims to explore the mechanisms by which platelet dysfunctions contribute to the disruption of hemostasis, leading to an increased risk of both thrombosis and bleeding. Platelets, traditionally known for their role in clot formation, can exhibit altered functionality under pathological conditions such as cardiovascular diseases, metabolic disorders, and autoimmune diseases, impacting their interaction with coagulation factors and vascular endothelium. The review discusses the molecular and cellular mechanisms underlying platelet dysfunction, including aberrations in platelet activation, aggregation, and secretion. It also highlights the interplay between platelets and other components of the coagulation cascade, such as fibrinogen and clotting factors, in maintaining vascular integrity. Moreover, the review examines clinical implications, including how platelet dysfunction can be a contributing factor in conditions like deep vein thrombosis, stroke, and disseminated intravascular coagulation (DIC). Finally, current therapeutic approaches targeting platelet dysfunctions, including antiplatelet agents and emerging therapies, are reviewed to provide insights into potential strategies for managing fluid-coagulation system imbalances. This review underscores the importance of a comprehensive understanding of platelet dysfunction to improve diagnosis and treatment of hemostatic disorders.

Clopidogrel protects against gentamicin-induced nephrotoxicity through targeting oxidative stress, apoptosis, and coagulation pathways

Gentamicin (Genta)-induced nephrotoxicity poses a significant clinical challenge due to its detrimental effects on kidney function. Clopidogrel (Clop), an antiplatelet drug known for its ability to prevent blood clots by inhibiting platelet aggregation, also has potential effects on oxidative stress and cell death. This study investigates Clop's protective role against Genta-induced nephrotoxicity, emphasizing the importance of the coagulation cascade. The 32 adult male albino rats were randomly assigned to four groups of eight (n = 8). The first group received only the vehicle. Genta was injected intraperitoneally at 100 mg/kg/day for 8 days in the second group. Groups 3 and 4 received oral Clop at 10 and 20 mg/kg/day for 1 week before Genta delivery and throughout the experiment. Renal tissue showed renal function tests, oxidative stress, pro-inflammatory cytokines, apoptotic markers, coagulation profile, and fibrin expression. Clop improved Genta-induced kidney function and histopathology. Clop substantially reduced pro-inflammatory cytokines, oxidative stress indicators, pro-apoptotic proteins, and fibrin protein. Clop also significantly boosted renal tissue anti-inflammatory and anti-apoptotic protein expression. Genta-induced nephrotoxicity involves oxidative stress, apoptosis, and coagulation system activation, according to studies. This study underscores that Genta-induced nephrotoxicity is associated with oxidative stress, apoptosis, and activation of the coagulation system. Clop's protective effects on nephrons are attributed to its anticoagulant, antioxidant, anti-inflammatory, and anti-apoptotic properties, presenting it as a promising therapeutic strategy against Genta-induced kidney damage.

Polydatin mitigates thrombosis by inhibiting PHD2-induced proline hydroxylation on collagen, reducing platelet adhesion

BACKGROUND

Platelet adhesion to collagen, a critical initial step in thrombus formation, remains an underexplored therapeutic target in thrombosis. Current disease treatment strategies primarily focus on platelet activation and aggregation, often overlooking the crucial initial adhesion phase. Reynoutria japonica (Huzhang, HZ), utilized in traditional Chinese medicine to enhance blood circulation and resolve blood stasis, lacks comprehensive insights into its active components and their anti-thrombotic mechanisms.

PURPOSE

This study investigated the antithrombotic effects and mechanisms of polydatin, a stilbene derived from HZ, with a focus on its effect on platelet adhesion.

METHODS

An acute pulmonary infection model was used, along with metabolomic and proteomic analyses, to investigate the antithrombotic efficacy of the active component polydatin and identify its targets. Chemical biology, protein mass spectrometry analyses, and molecular interaction analysis were performed to investigate its mechanism. Multiple models of circulatory disorders, including disseminated intravascular coagulation (DIC) and atherosclerosis in mice, with or without targeted gene knockdown, were employed to assess the role of polydatin in modulating platelet adhesion.

RESULTS

Our investigation revealed that polydatin targets prolyl hydroxylase 2 (PHD2), thereby inhibiting hydroxylation of proline residues on collagen. This disruption in collagen assembly and the von Willebrand factor (VWF)-collagen interaction reduces platelet adhesion, significantly impacting circulation in both DIC and atherosclerosis. This represents a novel mechanism of antithrombotic action, distinct from currently available therapies.

CONCLUSION

Targeting PHD2 to modulate collagen structure and platelet adhesion presents a promising novel therapeutic strategy for thrombosis-related circulatory disorders.

Inhibition of platelet activation process upon tris (2-chloroethyl) phosphate exposure: Role of PFKP-mediated glycolysis and the pentose phosphate pathway

Tris (2-chloroethyl) phosphate (TCEP), recognized as an emerging pollutant, has been frequently detected in human blood. Maintenance of blood homeostasis is indispensable for regulating various physiological states and overall health, yet hematological toxicology of TCEP has not been extensively investigated. Platelets, a vital component of blood, are fundamental in the processes of hemostasis and thrombosis through their activation; thus, this study was designed to elucidate the effects and underlying mechanisms of TCEP on platelet activation. Utilizing an in vivo model, we conducted a proteomic analysis of platelets and found that TCEP exposure inhibited platelet activation. An ex vivo platelet evaluation system was employed to further dissect the processes of platelet activation, revealing that TCEP predominantly suppressed platelet aggregation, degranulation and clot retraction. These processes were highly dependent on energy metabolism, and TCEP was found to decrease ATP levels, primarily by impairing glycolysis and pentose phosphate pathways. Subsequent investigation into the molecular mechanisms revealed that TCEP decreased the activity of phosphofructokinase platelet (PFKP) by enhancing O-linked N-acetylglucosamine (O-GlcNAc) transferase interaction with PFKP. This study is the first to uncover the disruptive effects of TCEP on platelet activation process, providing valuable insights into the assessment of hematologic health risks associated with TCEP-like emerging pollutants exposure.

Metagenomic Insights into Microbial Signatures in Thrombi from Acute Ischemic Stroke Patients Undergoing Endovascular Treatment

Background: Variability in recanalization success during endovascular treatment for acute ischemic stroke (AIS) has led to increased interests in thrombus composition and associated cellular materials. While evidence suggests that bacteria may influence thrombus characteristics, limited data exist on microbiological profiles of thrombi in stroke patients. Objectives: Characterization of bacterial communities present in thrombi of AIS patients undergoing mechanical thrombectomy, providing insights into microbial contributions to stroke pathogenesis and treatment outcomes. Methods: Thrombi were collected from 20 AIS patients. After extracting metagenome, 16S rDNA sequencing was performed. Bioinformatic analysis included taxonomy and diversity assessments. The presence of bacterial DNA and viable bacteria in thrombi was validated using polymerase chain reaction (PCR) and bacterial culturing followed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analysis, respectively. Results: 16S rDNA was amplified in 19/20 thrombi (95%). Analysis identified a diverse microbial community, with Corynebacterium spp. as the most prevalent genus, followed by Staphylococcus spp., Bifidobacterium spp., Methylobacterium spp., and Anaerococcus spp. Alpha diversity analyses (Shannon index: 4.0-6.0 and Simpson index: 0.8-1.0) revealed moderate to high microbial diversity across samples; beta diversity demonstrated distinct clustering, indicating inter-patient variability in microbial profiles. PCR confirmed the presence of DNA specific to dominant bacterial taxa identified through sequencing. Culturing showed the presence of Staphylococcus epidermidis and Enterococcus faecalis in some clots as identified through MALDI analysis. Conclusions: This study shows bacterial communities present in AIS patients' thrombi, suggesting a potential link between microbial signatures and thrombus characteristics.

Platelet-derived biomaterials for targeted drug delivery and tissue repair

Platelets are nucleic-free cells with a lifespan of 7-10 days in the bloodstream, playing a crucial role in various physiological processes such as hemostasis, thrombus formation, tumor development and metastasis, inflammation, and host defense. By utilizing the unique structural and functional characteristics of platelets, platelet-modified nano-drugs can evade immune recognition and clearance and facilitate prolonged circulation in vivo, which ultimately allows the nanoparticles to reach sites of disease such as thrombi, tumors, inflammation, or bacterial infections, leading to specific adhesion and significantly enhancing the efficiency of targeted drug delivery. This paper reviews the novel design and application of platelet-derived biomaterials in various diseases in recent years and comprehensively demonstrates the potential of platelet-derived biomaterials in the fields of disease therapy and biodefence, which will provide a reference for advancing the development of platelet-derived biomaterials and clinical practice.

Association between air pollutants and blood cell counts in pediatric patients with asthma: a retrospective observational study

BACKGROUND

Asthma is a common respiratory disease in children, and air pollution is a risk factor for pediatric asthma. However, how air pollution affects blood cells in pediatric patients with asthma remains unclear.

METHODS

This retrospective observational study, performed in 2007-2018 at a medical center, enrolled non-trauma patients aged < 17 years who visited the emergency department and had asthma. Medical records and blood cell counts, including absolute neutrophil count (ANC), eosinophil count, and platelet count were extracted. The concentrations of PM2.5, PM10, sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) were measured from 11 air-monitoring stations in Kaohsiung City.

RESULTS

One-unit increases in PM2.5 (regression coefficient: 25.618; S.E.: 5.937; p < 0.001), PM10 (19.97; 3.541; p < 0.001), NO2 (70.681; 15.857; p < 0.001), SO2 (81.694; 30.339; p = 0.007), and O3 (23.42; 8.831; p = 0.022) on lag 0-6 (7 d average) correlated positively with ANC. One-unit increases in PM2.5 (0.859; 0.357; p = 0.016), PM10 (0.728; 0.213; p = 0.001), and SO2 (4.086; 1.811; p = 0.024) on lag 0-6 correlated positively with eosinophil count. Additionally, one-unit increases in PM2.5 (0.302; 0.101; p = 0.003) and PM10 (0.229; 0.06; p < 0.001) on lag 0-6 correlated positively with platelet count. In a two-pollutant model, the impacts of PM2.5 and PMC on ANC and platelet count remained statistically significant after adjusting for other air pollutants. Additionally, PMC correlated significantly with eosinophil count after adjusting for PM2.5, NO2, SO2, and O3. Quartile increases in PM2.5 and PMC levels correlated positively with ANC, eosinophil count, and platelet count (all p for trend < 0.05).

CONCLUSIONS

PM2.5, PMC, and NO2 were independently and positively associated with ANC, PMC was positively associated with eosinophil count, and PM2.5 and PMC were positively associated with platelet count in pediatric patients with asthma. Our results highlight the relationship between air pollution and blood cell counts in pediatric patients with asthma.

From Blood to Therapy: The Revolutionary Application of Platelets in Cancer-Targeted Drug Delivery

Biomimetic nanodrug delivery systems based on cell membranes have emerged as a promising approach for targeted cancer therapy due to their biocompatibility and low immunogenicity. Among them, platelet-mediated systems are particularly noteworthy for their innate tumor-homing and cancer cell interaction capabilities. These systems utilize nanoparticles shielded and directed by platelet membrane coatings for efficient drug delivery. This review highlights the role of platelets in cancer therapy, summarizes the advancements in platelet-based drug delivery systems, and discusses their integration with other cancer treatments. Additionally, it addresses the limitations and challenges of platelet-mediated drug delivery, offering insights into future developments in this innovative field.

Research progress on platelets in glioma

ABSTRACT

Gliomas are the most common primary neuroepithelial tumors of the central nervous system in adults, of which glioblastoma is the deadliest subtype. Apart from the intrinsically indestructible characteristics of glioma (stem) cells, accumulating evidence suggests that the tumor microenvironment also plays a vital role in the refractoriness of glioblastoma. The primary functions of platelets are to stop bleeding and regulate thrombosis under physiological conditions. Furthermore, platelets are also active elements that participate in a variety of processes of tumor development, including tumor growth, invasion, and chemoresistance. Glioma cells recruit and activate resting platelets to become tumor-educated platelets (TEPs), which in turn can promote the proliferation, invasion, stemness, and chemoresistance of glioma cells. TEPs can be used to obtain genetic information about gliomas, which is helpful for early diagnosis and monitoring of therapeutic effects. Platelet membranes are intriguing biomimetic materials for developing efficacious drug carriers to enhance antiglioma activity. Herein, we review the recent research referring to the contribution of platelets to the malignant characteristics of gliomas and focusing on the molecular mechanisms mediating the interaction between TEPs and glioma (stem) cells, as well as present the challenges and opportunities in targeting platelets for glioma therapy.

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.

Structural and Functional Biology of Mammalian ALOX Isoforms with Particular Emphasis on Enzyme Dimerization and Their Allosteric Properties

The human genome involves six functional arachidonic acid (AA) lipoxygenase (ALOX) genes, and the corresponding enzymes (ALOX15, ALOX15B, ALOX12, ALOX12B, ALOXE3, ALOX5) have been implicated in cell differentiations and in the pathogenesis of inflammatory, hyperproliferative, metabolic, and neurological disorders. Humans express two different AA 15-lipoxygenating ALOX isoforms, and these enzymes are called ALOX15 (15-LOX1) and ALOX15B (15-LOX2). Chromosomal localization, sequence alignments, and comparison of the enzyme properties suggest that pig and mouse ALOX15 orthologs (leukocyte-type 12-LOX) on the one hand and rabbit and human ALOX15 orthologs on the other (reticulocyte-type 15-LOX1) belong to the same enzyme family despite their different reaction specificities with AA as a substrate. In contrast, human ALOX12 (platelet-type 12-LOX), as well as pig and mouse ALOX15 (leukocyte-type 12-LOX), belong to different enzyme families, although they exhibit a similar reaction specificity with AA as a substrate. The complex multiplicity of mammalian ALOX isoforms and the controversial enzyme nomenclatures are highly confusing and prompted us to summarize the current knowledge on the biological functions, enzymatic properties, and allosteric regulation mechanisms of mammalian ALOX15, ALOX15B, and ALOX12 orthologs that belong to three different enzyme sub-families.

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.

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.

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.

Platelet-to-albumin ratio: a potential biomarker for predicting all-cause and cardiovascular mortality in patients undergoing peritoneal dialysis

BACKGROUND

Although peritoneal dialysis (PD) is an efficient therapy for renal replacement, the long-term survival rate of patients undergoing PD remains low. The platelet-to-albumin ratio (PAR), recently identified as a parameter of inflammatory and nutritional status, is associated with an adverse prognosis for various diseases. However, the association between the serum PAR and prognosis of patients undergoing PD is poorly understood. This study aimed to evaluate whether the PAR is a reliable predictor of cardiovascular disease (CVD) and all-cause mortality in patients undergoing PD.

METHODS

This multicenter cohort study enrolled patients undergoing PD from January 1, 2009, to September 30, 2018. The patients were divided into four groups according to the quartiles of their baseline PAR. The primary endpoint was all-cause and CVD-related mortality. Cox proportional hazard models were used to determine the association between the PAR and all-cause or CVD-related mortality. The receiver operating characteristic (ROC) curve was utilized to compare the performance among PAR and other inflammatory indicators. C-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were applied to examine the incremental prognostic value of PAR compared with baseline model for predicting all-cause and CVD mortality.

RESULTS

A total of 2825 patients were included. During the follow-up period of 47.5 ± 28.3 months, 747 (26.4%) mortality cases were observed, of which 415 (55.6%) were CVD-related. Compared with the Q1 (PAR < 4.43), placement in Q4 (PAR > 7.27) was associated with an increased risk of all-cause mortality and CVD mortality (p < 0.001). The adjusted restricted cubic spline analysis indicated that the relationship of the PAR with all-cause and cardiovascular mortality was linear (p for nonlinearity = 0.289 and 0.422, respectively). No positive correlations were shown in the interaction tests. PAR exhibited superior predictive value for mortality compared to other inflammatory indicators, with a respective AUC value of 0.611 (P < 0.001) for all-cause mortality and 0.609 (P < 0.001) for cardiovascular mortality. According to the C-statistic, continuous NRI and IDI, the addition of PAR to the baseline model yielded a moderate but significant improvement in outcome prediction.

CONCLUSIONS

The PAR is an independent prognostic factor associated with all-cause and cardiovascular mortality in patients undergoing PD.

SARS-CoV-2 spike protein potentiates platelet aggregation via upregulating integrin αIIbβ3 outside-in signaling pathway

Platelet hyperreactivity is one of the crucial causes of coagulative disorders in patients with COVID-19. Few studies have indicated that integrin αIIbβ3 may be a potential target for spike protein binding to platelets. This study aims to investigate whether spike protein interacts with platelet integrin αIIbβ3 and upregulates outside-in signaling to potentiate platelet aggregation. In this study, we found that spike protein significantly potentiated platelet aggregation induced by different agonists and platelet spreading in vitro. Mechanism studies revealed that spike protein upregulated the outside-in signaling, such as increased thrombin-induced phosphorylation of β3, c-Src. Moreover, using tirofiban to inhibit spike protein binding to αIIbβ3 or using PP2 to block outside-in signaling, we found that the potentiating effect of spike protein on platelet aggregation was abolished. These results demonstrate that SARS-CoV-2 spike protein directly enhances platelet aggregation via integrin αIIbβ3 outside-in signaling, and suggest a potential target for platelet hyperreactivity in patients with COVID-19. HIGHLIGHTS: • Spike protein potentiates platelet aggregation and upregulates αIIbβ3 outside-in signaling. • Spike protein interacts with integrin αIIbβ3 to potentiate platelet aggregation. • Blocking outside-in signaling abolishes the effect of spike protein on platelets.

The Impact of Convertase Subtilisin/Kexin Type 9 Monoclonal Antibodies with and without Apheresis on Platelet Aggregation in Familial Hypercholesterolemia

BACKGROUND AND AIMS

It is well known that elevated cholesterol is associated with enhanced platelet aggregation and patients suffering from familial hypercholesterolemia (FH) have a high risk of thrombotic cardiovascular events. Although decreasing cholesterol level is associated with attenuation of platelet hyperactivity, there are currently no data on the effect of convertase subtilisin/kexin type 9 monoclonal antibodies (PCSK9ab) on platelet reactivity in FH. The aim of the study was to analyse the impact of different therapies including PCSK9ab on platelet aggregation in FH.

METHODS

This study enrolled all 15 patients treated in the University Hospital Hradec Králové for FH. PCSK9ab have been administered in 12 of 15 patients while 8 patients were also undergoing lipid apheresis. Blood samples from all patients including pre- and post-apheresis period were tested for platelet aggregation triggered by 7 inducers, and the effect of 3 clinically used drugs (acetylsalicylic acid, ticagrelor and vorapaxar) was compared as well.

RESULTS

Although apheresis decreased the reactivity of platelets in general, platelet responses were not different between non-apheresis patients treated with PCSK9ab and apheresis patients (post-apheresis values) with the exception of ristocetin. However, when compared to age-matched healthy population, FH patients had significantly lower platelet aggregation responses to 4 out of 7 used inducers and higher profit from 2 out of 3 used antiplatelet drugs even after exclusion of FH patients regularly receiving conventional antiplatelet treatment.

CONCLUSION

This study showed for the first time the suitability of PCSK9ab treatment for reduction of platelet reactivity in FH patients.

USP15-Mediated Deubiquitination of FKBP 5 and Activation of the αIIbβ3 Signaling Pathway Regulate Thrombosis in Mice

BACKGROUND

Platelets have the hemostatic function, and their aberrant activation is associated with occlusive thrombus formation. Plasma exosomes are rich in platelets containing ubiquitin-specific peptidase 15 (USP15). Herein, we aim to explore the effect of USP15 on thrombosis, as well as expounding whether USP15 acts as an upstream target of FK506 binding protein 5 (FKBP5) to regulate occlusive thrombus formation.

METHODS

Washed human platelets were treated with thrombin for measurement of USP15 and FKBP5 expressions. USP15 loss/gain-of-function variant in HEK293 cells was performed by cell transfection, and the interaction between USP15 and FKBP5 was examined using immunoprecipitation and ubiquitination assays. Mice with USP15-knockout platelets (Plt USP15-/-) were modeled, and subjected to calculation of bleeding time, artery thrombosis imaging and clot retraction assay. FKBP5 expression and the inhibitor of nuclear factor kappa B kinase subunit epsilon (IKBKE)/phosphatidylinositol 3-kinase (PI3K)/Rap1 pathway in wild-type and Plt USP15-/- mice-derived platelets were detected using Western blot. The activation of αIIbβ3 in washed platelets was analyzed using flow cytometry.

RESULTS

USP15 and FKBP5 expressions were upregulated in platelets after thrombin treatment. Following transfection of USP15 knockdown and USP15 overexpression plasmids into HEK293 cells, FKBP5 protein expression was downregulated by USP15 knockdown while being upregulated by USP15 overexpression. USP15 bound to FKBP5 and protected FKBP5 against ubiquitination. Knockdown of platelet USP15 prolonged bleeding time, inhibited arterial thrombosis and delayed clot retraction in mice. Knockdown of platelet USP15 also decreased protein expressions of FKBP5, IKBKE and Rap1, p-PI3K/PI3K ratio, and activation of αIIbβ3 in mice.

CONCLUSION

USP15 knockdown in platelets affects thrombosis in mice by promoting the instability of FKBP5 to repress the activation of IKBKE/PI3K/Rap1 pathway-mediated αIIbβ3.

The role of integrins in brain health and neurodegenerative diseases

Integrins are heterodimeric membrane proteins expressed on the surface of most cells. They mediate adhesion and signaling processes relevant for a wealth of physiological processes, including nervous system development and function. Interestingly, integrins are also recognized therapeutic targets for inflammatory diseases, such as multiple sclerosis. Here, we discuss the role of integrins in brain development and function, as well as in neurodegenerative diseases affecting the brain (Alzheimer's disease, multiple sclerosis, stroke). Furthermore, we discuss therapeutic targeting of these adhesion receptors in inflammatory diseases of the brain.

Platelet lipidomics and de novo lipogenesis: impact on health and disease

PURPOSE OF REVIEW

Lipids play vital roles in platelet structure, signaling, and metabolism. In addition to capturing exogenous lipids, platelets possess the capacity for de novo lipogenesis, regulated by acetyl-coA carboxylase 1 (ACC1). This review aims to cover the critical roles of platelet de novo lipogenesis and lipidome in platelet production, function, and diseases.

RECENT FINDINGS

Upon platelet activation, approximately 20% of the platelet lipidome undergoes significant modifications, primarily affecting arachidonic acid-containing species. Multiple studies emphasize the impact of de novo lipogenesis, with ACC1 as key player, on platelet functions. Mouse models suggest the importance of the AMPK-ACC1 axis in regulating platelet membrane arachidonic acid content, associated with TXA 2 secretion, and thrombus formation. In human platelets, ACC1 inhibition leads to reduced platelet reactivity. Remodeling of the platelet lipidome, alongside with de novo lipogenesis, is also crucial for platelet biogenesis. Disruptions in the platelet lipidome are observed in various pathological conditions, including cardiovascular and inflammatory diseases, with associations between these alterations and shifts in platelet reactivity highlighted.

SUMMARY

The platelet lipidome, partially regulated by ACC-driven de novo lipogenesis, is indispensable for platelet production and function. It is implicated in various pathological conditions involving platelets.

Thrombotic events associated with immune checkpoint inhibitors and novel antithrombotic strategies to mitigate bleeding risk

Although immunotherapy is expanding treatment options for cancer patients, the prognosis of advanced cancer remains poor, and these patients must contend with both cancers and cancer-related thrombotic events. In particular, immune checkpoint inhibitors are associated with an increased risk of atherosclerotic thrombotic events. Given the fundamental role of platelets in atherothrombosis, co-administration of antiplatelet agents is always indicated. Platelets are also involved in all steps of cancer progression. Classical antithrombotic drugs can cause inevitable hemorrhagic side effects due to blocking integrin β3 bidirectional signaling, which regulates simultaneously thrombosis and hemostasis. Meanwhile, many promising new targets are emerging with minimal bleeding risk and desirable anti-tumor effects. This review will focus on the issue of thrombosis during immune checkpoint inhibitor treatment and the role of platelet activation in cancer progression as well as explore the mechanisms by which novel antiplatelet therapies may exert both antithrombotic and antitumor effects without excessive bleeding risk.

Current status and future perspectives of platelet-derived extracellular vesicles in cancer diagnosis and treatment

Platelets are a significant component of the cell population in the tumour microenvironment (TME). Platelets influence other immune cells and perform cross-talk with tumour cells, playing an important role in tumour development. Extracellular vesicles (EVs) are small membrane vesicles released from the cells into the TME. They can transfer biological information, including proteins, nucleic acids, and metabolites, from secretory cells to target receptor cells. This process affects the progression of various human diseases, particularly cancer. In recent years, several studies have demonstrated that platelet-derived extracellular vesicles (PEVs) can help regulate the malignant biological behaviours of tumours, including malignant proliferation, resistance to cell death, invasion and metastasis, metabolic reprogramming, immunity, and angiogenesis. Consequently, PEVs have been identified as key regulators of tumour progression. Therefore, targeting PEVs is a potential strategy for tumour treatment. Furthermore, the extensive use of nanomaterials in medical research has indicated that engineered PEVs are ideal delivery systems for therapeutic drugs. Recent studies have demonstrated that PEV engineering technologies play a pivotal role in the treatment of tumours by combining photothermal therapy, immunotherapy, and chemotherapy. In addition, aberrant changes in PEVs are closely associated with the clinicopathological features of patients with tumours, which may serve as liquid biopsy markers for early diagnosis, monitoring disease progression, and the prognostic assessment of patients with tumours. A comprehensive investigation into the role and potential mechanisms of PEVs in tumourigenesis may provide novel diagnostic biomarkers and potential therapeutic strategies for treating human tumours.

Altered dynamics of calcium fluxes and mitochondrial metabolism in platelet activation-related disease and aging

Understanding the mechanisms controlling platelet function is crucial for exploring potential therapeutic targets related to atherothrombotic pathologies and primary hemostasis disorders. Our research, which focuses on the role of platelet mitochondria and Ca2+ fluxes in platelet activation, the formation of the procoagulant phenotype, and thrombosis, has significant implications for the development of new therapeutic strategies. Traditionally, Ca2+-dependent cellular signaling has been recognized as a determinant process throughout the platelet activation, controlled primarily by store-operated Ca2+ entry and the PLC-PKC signaling pathway. However, despite the accumulated knowledge of these regulatory mechanisms, the effectiveness of therapy based on various commonly used antiplatelet drugs (such as acetylsalicylic acid and clopidogrel, among others) has faced challenges due to bleeding risks and reduced efficacy associated with the phenomenon of high platelet reactivity. Recent evidence suggests that platelet mitochondria could play a fundamental role in these aspects through Ca2+-dependent mechanisms linked to apoptosis and forming a procoagulant phenotype. In this context, the present review describes the latest advances regarding the role of platelet mitochondria and Ca2+ fluxes in platelet activation, the formation of the procoagulant phenotype, and thrombosis.

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

BACKGROUND

Titanium dioxide nanoparticles (TiO2NPs) are widely used in medical application. However, the relevant health risk has not been completely assessed, the potential of inducing arterial thrombosis (AT) in particular.

METHODS

Alterations in platelet function and susceptibility to arterial thrombosis induced by TiO2NPs were examined using peripheral blood samples from healthy adult males and an in vivo mouse model, respectively.

RESULTS

Here, using human platelets (hPLTs) freshly isolated from health volunteers, we demonstrated TiO2NP treatment triggered the procoagulant activity of hPLTs through phosphatidylserine exposure and microvesicles generation. In addition, TiO2NP treatment increased the levels of glycoprotein IIb/IIIa and P-selectin leading to aggregation and activation of hPLTs, which were exacerbated by providing physiology-mimicking conditions, including introduction of thrombin, collagen, and high shear stress. Interestingly, intracellular calcium levels in hPLTs were increased upon TiO2NP treatment, which were crucial in TiO2NP-induced hPLT procoagulant activity, activation and aggregation. Moreover, using mice in vivo models, we further confirmed that TiO2NP treatment a reduction in mouse platelet (mPLT) counts, disrupted blood flow, and exacerbated carotid arterial thrombosis with enhanced deposition of mPLT.

CONCLUSIONS

Together, our study provides evidence for an ignored health risk caused by TiO2NPs, specifically TiO2NP treatment augments procoagulant activity, activation and aggregation of PLTs via calcium-dependent mechanism and thus increases the risk of AT.

Unleashing the biomimetic targeting potential of platelet-derived nanocarriers on atherosclerosis

Atherosclerosis, the primary mechanism underlying the development of many cardiovascular illnesses, continues to be one of the leading causes of mortality worldwide. Platelet (PLT), which are essential for maintaining body homeostasis, have been strongly linked to the onset of atherosclerosis at various stages due to their inherent tendency to bind to atherosclerotic lesions and show an affinity for plaques. Therefore, mimicking PLT's innate adhesive features may be necessary to effectively target plaques. PLT-derived nanocarriers have emerged as a promising biomimetic targeting strategy for treating atherosclerosis due to their numerous advantages. These advantages include excellent biocompatibility, minimal macrophage phagocytosis, prolonged circulation time, targeting capability for impaired vascular sites, and suitability as carriers for anti-atherosclerotic drugs. Herein, we discuss the role of PLT in atherogenesis and propose the design of nanocarriers based on PLT-membrane coating and PLT-derived vesicles. These nanocarriers can target multiple biological elements relevant to plaque development. The review also emphasizes the current challenges and future research directions for the effective utilization of PLT-derived nanocarriers in treating atherosclerosis.

Fibrinogen binding to activated platelets and its biomimetic thrombus-targeted thrombolytic strategies

Thrombosis is associated with various fatal arteriovenous syndromes including ischemic stroke, myocardial infarction, and pulmonary embolism. However, current clinical thrombolytic treatment strategies still have many problems in targeting and safety to meet the thrombolytic therapy needs. Understanding the molecular mechanism that underlies thrombosis is critical in developing effective thrombolytic strategies. It is well known that platelets play a central role in thrombosis and the binding of fibrinogen to activated platelets is a common pathway in the process of clot formation. Based on this, a concept of biomimetic thrombus-targeted thrombolytic strategy inspired from fibrinogen binding to activated platelets in thrombosis was proposed, which could selectively bind to activated platelets at a thrombus site, thus enabling targeted delivery and local release of thrombolytic agents for effective thrombolysis. In this review, we first summarized the main characteristics of platelets and fibrinogen, and then introduced the classical molecular mechanisms of thrombosis, including platelet adhesion, platelet activation and platelet aggregation through the interactions of activated platelets with fibrinogen. In addition, we highlighted the recent advances in biomimetic thrombus-targeted thrombolytic strategies which inspired from fibrinogen binding to activated platelets in thrombosis. The possible future directions and perspectives in this emerging area are briefly discussed.

Clot Accumulation in 3D Microfluidic Bifurcating Microvasculature Network

The microvasculature, which makes up the majority of the cardiovascular system, plays a crucial role in the process of thrombosis, with the pathological formation of blood clots inside blood vessels. Since blood microflow conditions significantly influence platelet activation and thrombosis, accurately mimicking the structure of bifurcating microvascular networks and emulating local physiological blood flow conditions are valuable for understanding blood clot formation. In this work, we present an in vitro model for blood clotting in microvessels, focusing on 3D bifurcations that align with Murray's law, which guides vascular networks by maintaining a constant wall shear rate throughout. Using these models, we demonstrate that microvascular bifurcations act as sites facilitating thrombus formation compared to straight models. Additionally, by culturing endothelial cells on the luminal surfaces of the models, we show the potential of using our in vitro platforms to recapitulate the initial clotting in diseases involving endothelial dysfunction, such as Thrombotic Thrombocytopenic Purpura.

Therapeutic effects and molecular mechanisms of natural products in thrombosis

Thrombotic disorders, such as myocardial infarction and stroke, are the leading cause of death in the global population and have become a health problem worldwide. Drug therapy is one of the main antithrombotic strategies, but antithrombotic drugs are not completely safe, especially the risk of bleeding at therapeutic doses. Recently, natural products have received widespread interest due to their significant efficacy and high safety, and an increasing number of studies have demonstrated their antithrombotic activity. In this review, articles from databases, such as Web of Science, PubMed, and China National Knowledge Infrastructure, were filtered and the relevant information was extracted according to predefined criteria. As a result, more than 100 natural products with significant antithrombotic activity were identified, including flavonoids, phenylpropanoids, quinones, terpenoids, steroids, and alkaloids. These compounds exert antithrombotic effects by inhibiting platelet activation, suppressing the coagulation cascade, and promoting fibrinolysis. In addition, several natural products also inhibit thrombosis by regulating miRNA expression, anti-inflammatory, and other pathways. This review systematically summarizes the natural products with antithrombotic activity, including their therapeutic effects, mechanisms, and clinical applications, aiming to provide a reference for the development of new antithrombotic drugs.

Investigation into safflower injection as a prophylactic treatment for retinal vein occlusion in a rabbit model

The study aimed to assess the effect and mechanism of safflower injection in preventing retinal vein thrombosis in rabbits. Twenty healthy adult pigmented rabbits were randomly assigned to either the experimental group, receiving safflower injection, or the control group, receiving normal saline. After two weeks of treatment, blood samples were collected to analyze platelet adhesion and aggregation rates. Photodynamic therapy was applied to induce occlusion in the target retinal vein. Fundus photography and fluorescein angiography were recorded using a dynamic microscopic monitoring system, and laser speckle imaging was employed to assess blood flow in the affected vein. The experimental group exhibited significantly lower rates of platelet adhesion and aggregation compared to the control group. Following the induction of retinal vein occlusion, the experimental group showed a lower complete occlusion rate of the target retinal vein. Although initial blood flow in the target vein was similar between groups, the blood flow at 1, 3, and 5 min post-occlusion was significantly higher in the experimental group. Safflower injection delayed retinal vein thrombosis formation, preserved blood flow in the affected retinal area, and reduced platelet adhesion and aggregation. These effects facilitated vascular reperfusion within a limited timeframe.

Desmopressin, Misoprostol, nor Carboprost Affect Platelet Aggregability Following Traumatic Brain Injury and Aspirin

INTRODUCTION

Desmopressin (DDAVP) has been utilized clinically in patients taking aspirin (ASA) to improve drug-induced platelet dysfunction. Misoprostol and carboprost, prostaglandin analogs commonly used for postpartum hemorrhage, may also induce platelet aggregation. The aim of this study was to determine the effects of DDAVP, misoprostol, and carboprost administration on platelet aggregability following traumatic brain injury (TBI) in mice treated with ASA.

METHODS

Male C57BL/6 mice were randomized into seven groups (n = 5 each): untouched, ASA only, Saline/TBI, ASA/TBI, ASA/TBI/DDAVP 0.4 μg/kg, ASA/TBI/misoprostol 1 mg/kg, and ASA/TBI/carboprost 100 μg/kg. TBI was induced via a weight drop model 4-h after ASA (50 mg/kg) gavage. Mice were given an intraperitoneal injection of DDAVP, misoprostol, or carboprost 10 minutes after TBI. In vivo testing was completed utilizing tail vein bleed. Mice were sacrificed 30-min posttreatment and blood was collected via cardiac puncture. Whole blood was analyzed via Multiplate impedance aggregometry, rotational thromboelastometry, and TEG6s.

RESULTS

Mice receiving misoprostol after ASA/TBI demonstrated decreased tail vein bleeding times compared to ASA only treated mice. However, mice treated with misoprostol following ASA and TBI demonstrated decreased platelet aggregability compared to untouched mice and TBI only mice within the arachidonic acid agonist pathway. By contrast, DDAVP and carboprost did not significantly change platelet aggregability via adenosine diphosphate or arachidonic acid following ASA and TBI. However, DDAVP did decrease the platelet contribution to clot via rotational thromboelastometry.

CONCLUSIONS

Reversal of medication-induced platelet inhibition has become increasingly controversial after TBI. Based on these results, DDAVP, misoprostol, nor carboprost consistently improve platelet aggregability following TBI in those also treated with ASA.

Metabolomics and network pharmacology reveal the mechanism of antithrombotic effect of Asperosaponin VI

Dipsaci Radix may possess antithrombotic properties, and one of its primary active ingredients is Asperosaponin VI. However, the antithrombotic effects and pharmacological mechanisms of Asperosaponin VI remain unclear. An in vivo experimental study has demonstrated the antithrombotic activity of Asperosaponin VI. Asperosaponin VI also exhibits anticoagulant properties. Asperosaponin VI significantly hindered collagen adrenergic-induced acute pulmonary thrombosis in mice and enhanced their survival rate. This hinders the formation of acute pulmonary embolisms induced by adenosine diphosphate (ADP) and decreases recovery time. A comprehensive strategy that combines metabolomics, network pharmacology, molecular docking, and experimental validation has the potential to reveal the antithrombotic mechanisms of Asperosaponin VI. Metabolomic evidence suggests that Asperosaponin VI may influence platelet aggregation and the production of anti-inflammatory metabolites through the regulation of pathways such as phenylalanine and arachidonic acid metabolism, thereby inhibiting thrombosis. Network pharmacology identified the pharmacological targets of Asperosaponin VI and indicated that it treats thrombi by partially regulating the signaling pathways related to inflammation and platelet aggregation. Asperosaponin VI showed strong binding affinity for F2, PTPRC, JUN, STAT3, SRC, AKT1. The antiplatelet aggregation activity of Asperosaponin VI was validated based on the metabolomic and network pharmacology results. Asperosaponin VI inhibits platelet aggregation induced by ADP, AA, and collagen. Therefore, Asperosaponin VI exerts antithrombotic effects through antiplatelet aggregation. Therefore, Asperosaponin VI is a promising antithrombotic agent.

Construction and applications of the EOMA spheroid model of Kaposiform hemangioendothelioma

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare intermediate vascular tumor with unclear pathogenesis. Recently, three dimensional (3D) cell spheroids and organoids have played an indispensable role in the study of many diseases, such as infantile hemangioma and non-involuting congenital hemangiomas. However, few research on KHE are based on the 3D model. This study aims to evaluate the 3D superiority, the similarity with KHE and the ability of drug evaluation of EOMA spheroids as an in vitro 3D KHE model.

RESULTS

After two days, relatively uniform morphology and high viability of EOMA spheroids were generated by the rotating cell culture system (RCCS). Through transcriptome analysis, compared with 2D EOMA cells, focal adhesion-related genes such as Itgb4, Flt1, VEGFC, TNXB, LAMA3, VWF, and VEGFD were upregulated in EOMA spheroids. Meanwhile, the EOMA spheroids injected into the subcutaneous showed more obvious KMP than 2D EOMA cells. Furthermore, EOMA spheroids possessed the similar characteristics to the KHE tissues and subcutaneous tumors, such as diagnostic markers (CD31 and LYVE-1), cell proliferation (Ki67), hypoxia (HIF-1α) and cell adhesion (E-cadherin and N-cadherin). Based on the EOMA spheroid model, we discovered that sirolimus, the first-line drug for treating KHE, could inhibit EOMA cell proliferation and downregulate the VEGFC expression. Through the extra addition of VEGFC, the effect of sirolimus on EOMA spheroid could be weakened.

CONCLUSION

With a high degree of similarity of the KHE, 3D EOMA spheroids generated by the RCCS can be used as a in vitro model for basic researches of KHE, generating subcutaneous tumors and drug screening.

Molecular architecture and platelet-activating properties of small immune complexes assembled on heparin and platelet factor 4

Heparin-induced thrombocytopenia (HIT) is an adverse reaction to heparin leading to a reduction in circulating platelets with an increased risk of thrombosis. It is precipitated by polymerized immune complexes consisting of pathogenic antibodies that recognize a small chemokine platelet factor 4 (PF4) bound to heparin. Characterization of these immune complexes is extremely challenging due to the enormous structural heterogeneity of such macromolecular assemblies and their constituents. Native mass spectrometry demonstrates that up to three PF4 tetramers can be assembled on a heparin chain, consistent with the molecular modeling studies showing facile polyanion wrapping along the polycationic belt on the PF4 surface. Although these assemblies can accommodate a maximum of only two antibodies, the resulting immune complexes are capable of platelet activation despite their modest size. Taken together, these studies provide further insight into molecular mechanisms of HIT and other immune disorders where anti-PF4 antibodies play a central role.

Reduced IgG2 with thrombocytopenia predicts mortality in patients with influenza pneumonia

BACKGROUND

Thrombocytopenia is a common disorder during influenza that is related to high mortality.

OBJECTIVES

A prospective study was performed to investigate the association of immunoglobulin subclass changes accompanying incident thrombocytopenia with clinical outcomes in patients with severe influenza.

METHODS

96 influenza patients were recruited and divided into two groups, patients with thrombocytopenia (n = 30) and patients without thrombocytopenia (n = 66). Plasma microarrays were used for quantitative analysis of immunoglobulins. The endpoint was 28-day mortality. Continuous platelet count, d-dimer, level of each Ig subclass and other variables were compared between the two groups. Kaplan-Meier curve was taken to analyze the 28-day survival rate of the two groups and Cox regression analysis was performed to identify variables independently associated with 28-day mortality.

RESULTS

Patients with thrombocytopenia had significantly high values of d-dimer at admission and when platelet lowest with high SOFA score. Their IgA2, IgG2, and IgG4 values were also lower than those without thrombocytopenia. Patients without thrombocytopenia had a higher 28-day survival rate than those in the thrombocytopenia group. In the multivariate Cox regression model, age (HR = 1.036, 95%CI = 1.011-1.062), IgG2 (HR = 0.990, 95%CI = 0.982-0.998), platelet minimum within 28 days (HR = 0.991, 95%CI = 0.982-0.999) and d-dimer when platelet lowest (HR = 1.091, 95%CI = 1.047-1.137) were independently related to 28-day mortality.

CONCLUSION

Decreased IgG2 may be associated with thrombocytopenia. A coexistence of thrombocytopenia, IgG2 reduction and d-dimer elevation may improve the accuracy of mortality prediction in patients with influenza pneumonia.

The combination of paeonol, diosmetin-7-O-β-D-glucopyranoside, and 5-hydroxymethylfurfural from Trichosanthis pericarpium alleviates arachidonic acid-induced thrombosis in a zebrafish model

Trichosanthis fruit (TF) is a classic medicinal material obtained from Shandong, China. The peel of this fruit (Trichosanthis pericarpium, TP) is known to exert anti-thrombotic effects. However, the anti-thrombotic active components and mechanisms of TP have yet to be fully elucidated. Combined with zebrafish models and high-performance liquid chromatography (HPLC), this study evaluated the endogenous anti-thrombotic effects with the combination of three compounds from TP. First, we used HPLC to investigate the components in the water extract of TP. Next, we used the zebrafish model to investigate the anti-thrombotic activity of the three compound combinations by evaluating a range of indicators. Finally, the expression of related genes was detected by real-time quantitative polymerase chain reaction (qPCR). HPLC detected a total of eight components in TP water extract, with high levels of paeonol (Pae), diosmetin-7-O-β-D-glucopyranoside (diosmetin-7-O-glucoside), and 5-hydroxymethylfurfural (5-HMF). The most significant anti-thrombotic activity was detected when the Pae: diosmetin-7-O-glucoside:5-HMF ratio was 4:3:3. qPCR analysis revealed that the abnormal expression levels of f2, fga, fgb, vwf, ptgs1, and tbxas1 induced by arachidonic acid (AA) were improved. The combination of Pae, diosmetin-7-O-glucoside, and 5-HMF may alleviate AA-induced thrombosis by inhibiting the inflammatory reaction, coagulation cascade reaction, and arachidonic acid metabolism pathways.

Systemic immune-inflammation index predicts first stroke and affects the efficacy of folic acid in stroke prevention

Background

Systemic immune-inflammation index (SII) is a novel biomarker of growing interest in predicting stroke. The aim of this study was to investigate its predictive value and explore its effect modification on folic acid supplement for stroke primary prevention in a Chinese population with hypertension.

Methods

A total of 10,013 participants from the China Stroke Primary Prevention Trial with available neutrophil, platelet and lymphocyte count were included, including 5,019 subjects in the enalapril group and 4,994 in the enalapril-folic acid group. SII was calculated as (platelet × neutrophil)/lymphocyte. The primary endpoint was first stroke. Cox proportional hazards models were used to evaluate the association between SII and first stroke.

Results

A U-shape association between SII and first stroke risk was observed in enalapril group. Compared with the reference group (Quartile 2: 335.1 to <443.9 × 109 cell/L), the adjusted HRs were 1.68 (95 % CI: 1.06-2.66, P = 0.027) in Quartile 1 (<335.1 × 109 cell/L), 1.43 (95 % CI: 0.90-2.27, P = 0.126) in Quartile 3 (443.9 to <602.6 × 109 cell/L), and 1.61 (95 % CI: 1.03-2.51, P = 0.035) in Quartile 4 (≥602.6 × 109 cell/L). There was no significant association between SII and first stroke in the enalapril-folic acid group, with adjusted HR of 0.92 (95%CI: 0.54-1.56, P = 0.749) in Quartile 1(<334.7 × 109 cell/L), 1.36 (95%CI: 0.84-2.21, P = 0.208) in Quartile 3 (446.2 to <595.2 × 109 cell/L), and 1.41 (95%CI: 0.87-2.27, P = 0.163) in Quartile 4 (≥595.2 × 109 cell/L). A remarkable interaction between baseline SII and folic acid supplement for stroke prevention was observed, with particularly reduced risk by 44 % (HR: 0.56; 95 % CI: 0.34-0.90; P = 0.018) in the lowest SII group (P for interaction = 0.041).

Conclusions

Among Chinese adults with hypertension, both low and high SII at baseline predicted increased first stroke risk. And compensatory folic acid particularly reduced first stroke risk in the lowest SII subgroup.

The role of platelets in the blood-brain barrier during brain pathology

Platelets play critical roles in maintaining hemostasis. The blood brain barrier (BBB), a significant physical and metabolic barrier, helps maintain physiological stability by limiting transportations between the blood and neural tissues. When the brain undergoes inflammation, tumor, trauma, or bleeding, the platelet responses to help with maintaining BBB homeostasis. In the traditional point of view, activated platelets aggregate to form thrombi which cover the gaps of the blood vessels to protect BBB. However, increasing evidences indicate that platelets may harm BBB by enhancing vascular permeability. Hereby, we reviewed recently published articles with a special focus on the platelet-mediated damage of BBB. Factors released by platelets can induce BBB permeability, which involve platelet-activating factors (PAF), P-selectin, ADP, platelet-derived growth factors (PDGF) superfamily proteins, especially PDGF-AA and PDGF-CC, etc. Platelets can also secrete Amyloid-β (Aβ), which triggers neuroinflammation and downregulates the expression of tight junction molecules such as claudin-5 to damage BBB. Additionally, platelets can form aggregates with neutrophils to release reactive oxygen species (ROS), which can destroy the DNA, proteins, and lipids of endothelial cells (ECs). Moreover, platelets participate in neuroinflammation to affect BBB. Conversely, some of the platelet released factors such as PDGF-BB, protects BBB. In summary, platelets play dual roles in BBB integrity and the related mechanisms are reviewed.

Platelet-enriched microRNAs as novel biomarkers in atherosclerotic and cardiovascular disease patients

BACKGROUND

Cardiovascular disease (CVD) is a global health challenge. Various studies have shown that genetic and environmental factors play roles in the development and progression of CVD. Small non-coding RNAs, namely microRNAs (miRs), regulate gene expression and have key roles in essential cellular processes such as apoptosis, cell cycle, differentiation, and proliferation. Currently, clinical studies highlight the critical role of platelets and miRs in coronary thrombosis, atherosclerosis, and CVD.

METHODS

Using search engines such as PubMed and Scopus, articles studying platelet miRs and their effects on atherosclerosis and cardiovascular disease were reviewed.

RESULTS

This article presents a comprehensive analysis of the association of platelet-related miRs as prognostic, diagnostic, and therapeutic biomarkers with the pathogenesis of atherosclerosis and cardiovascular disease.

CONCLUSION

Taken together, data show that platelet-related miRs not only play important roles in the initial development of atherosclerosis and cardiovascular disease (CVD), but they are also considered prognostic and diagnostic biomarkers in CVD.

Immunothrombosis versus thrombo-inflammation: platelets in cerebrovascular complications

A State-of-the Art lecture titled "Thrombo-Neuroinflammatory Disease" was presented at the International Society on Thrombosis and Haemostasis Congress in 2023. First, we would like to advocate for discrimination between immunothrombosis and thrombo-inflammation, as immunothrombosis describes an overshooting inflammatory reaction that results in detrimental thrombotic activity. In contrast, thrombo-inflammation describes the interplay of platelets and coagulation with the immunovascular system, resulting in the recruitment of immune cells and loss of barrier function (hence, hallmarks of inflammation). Both processes can be observed in the brain, with cerebral venous thrombosis being a prime example of immunothrombosis, while infarct progression in response to ischemic stroke is a paradigmatic example of thrombo-inflammation. Here, we review the pathomechanisms underlying cerebral venous thrombosis and ischemic stroke from a platelet-centric perspective and discuss translational implications. Finally, we summarize relevant new data on this topic presented during the 2023 International Society on Thrombosis and Haemostasis Congress.

Anti-atherosclerotic effects and molecular targets of ginkgolide B from Ginkgo biloba

Bioactive compounds derived from herbal medicinal plants modulate various therapeutic targets and signaling pathways associated with cardiovascular diseases (CVDs), the world's primary cause of death. Ginkgo biloba , a well-known traditional Chinese medicine with notable cardiovascular actions, has been used as a cardio- and cerebrovascular therapeutic drug and nutraceutical in Asian countries for centuries. Preclinical studies have shown that ginkgolide B, a bioactive component in Ginkgo biloba , can ameliorate atherosclerosis in cultured vascular cells and disease models. Of clinical relevance, several clinical trials are ongoing or being completed to examine the efficacy and safety of ginkgolide B-related drug preparations in the prevention of cerebrovascular diseases, such as ischemia stroke. Here, we present a comprehensive review of the pharmacological activities, pharmacokinetic characteristics, and mechanisms of action of ginkgolide B in atherosclerosis prevention and therapy. We highlight new molecular targets of ginkgolide B, including nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidase), lectin-like oxidized LDL receptor-1 (LOX-1), sirtuin 1 (SIRT1), platelet-activating factor (PAF), proprotein convertase subtilisin/kexin type 9 (PCSK9) and others. Finally, we provide an overview and discussion of the therapeutic potential of ginkgolide B and highlight the future perspective of developing ginkgolide B as an effective therapeutic agent for treating atherosclerosis.

The impact of platelet indices on ischemic stroke: a Mendelian randomization study and mediation analysis

Introduction

Platelet indices (PIs) are hematological parameters that indicate the number, morphology, and activation of platelets. Although some clinical trials suggest an association between PIs and the risk of stroke, the lack of robust evidence is attributed to confounding effects and reverse causation.

Objective

This study aimed to evaluate the association between PIs and stroke risk through Mendelian randomization (MR) while exploring the mediating effect of blood pressure in this association.

Methods

We identified genetic variants associated with PIs, including platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), and platelet crit (PCT), in the UK Biobank (n = 350,474). Relevant genome-wide association studies were utilized to gather summary statistics pertaining to the traits of interest. We primarily used the inverse-variance weighted analysis to obtain estimates for individual causal power.

Result

We observed a positive correlation between genetically predicted increases in PCT levels with the stroke onset [PCT: OR (95%CI) = 1.113(1.047, 1.183), p < 0.001]. However, no significant causal relationship was found between PLT, PDW, and MPV and the risk of stroke [PLT: OR (95%CI) = 1.037(0.979, 1.098), p = 0.221; PDW: OR (95%CI) = 0.973(0.923, 1.024), p = 0.294; MPV: OR (95%CI) = 0.990(0.945, 1.038), p = 0.675]. Multivariable MR analyses and mediation analysis found that the proportion mediated by systolic blood pressure (SBP) is 23.71% [95%CI (10.85-33.31%)] and the proportion mediated by diastolic blood pressure (DBP) is 28.09% [95%CI (12.92-39.63%)].

Conclusion

This large MR study presents evidence for the potential causal relationship between the PCT level and the risk of ischemic stroke, which might be mediated by blood pressure.

Regulation of toll-like receptor (TLR) signaling pathways in atherosclerosis: from mechanisms to targeted therapeutics

Atherosclerosis, one of the life-threatening cardiovascular diseases (CVDs), has been demonstrated to be a chronic inflammatory disease, and inflammatory and immune processes are involved in the origin and development of the disease. Toll-like receptors (TLRs), a class of pattern recognition receptors that trigger innate immune responses by identifying pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), regulate numerous acute and chronic inflammatory diseases. Recent studies reveal that TLRs have a vital role in the occurrence and development of atherosclerosis, including the initiation of endothelial dysfunction, interaction of various immune cells, and activation of a number of other inflammatory pathways. We herein summarize some other inflammatory signaling pathways, protein molecules, and cellular responses associated with TLRs, such as NLRP3, Nrf2, PCSK9, autophagy, pyroptosis and necroptosis, which are also involved in the development of AS. Targeting TLRs and their regulated inflammatory events could be a promising new strategy for the treatment of atherosclerotic CVDs. Novel drugs that exert therapeutic effects on AS through TLRs and their related pathways are increasingly being developed. In this article, we comprehensively review the current knowledge of TLR signaling pathways in atherosclerosis and actively seek potential therapeutic strategies using TLRs as a breakthrough point in the prevention and therapy of atherosclerosis.

The oxylipin analog CS585 prevents platelet activation and thrombosis through activation of the prostacyclin receptor

Cardiovascular disease remains the primary cause of morbidity and mortality globally. Platelet activation is critical for maintaining hemostasis and preventing the leakage of blood cells from the vessel. There has been a paucity in the development of new drugs to target platelet reactivity. Recently, the oxylipin 12(S)-hydroxy-eicosatrienoic acid (12-HETrE), which is produced in platelets, was shown to limit platelet reactivity by activating the prostacyclin receptor. Here, we demonstrated the synthesis of a novel analog of 12-HETrE, known as CS585. Human blood and mouse models of hemostasis and thrombosis were assessed for the ability of CS585 to attenuate platelet activation and thrombosis without increasing the risk of bleeding. Human platelet activation was assessed using aggregometry, flow cytometry, western blot analysis, total thrombus formation analysis system, microfluidic perfusion chamber, and thromboelastography. Hemostasis, thrombosis, and bleeding assays were performed in mice. CS585 was shown to potently target the prostacyclin receptor on the human platelet, resulting in a highly selective and effective mechanism for the prevention of platelet activation. Furthermore, CS585 was shown to inhibit platelet function in human whole blood ex vivo, prevent thrombosis in both small and large vessels in mouse models, and exhibit long-lasting prevention of clot formation. Finally, CS585 was not observed to perturb coagulation or increase the risk of bleeding in the mouse model. Hence, CS585 represents a new validated target for the treatment of thrombotic diseases without the risk of bleeding or off-target activation observed with other prostaglandin receptor agonists.