Increased Platelet Aggregation Research Articles

Obstructive Sleep Apnea, Platelet Aggregation, and Cardiovascular Risk.

Although related, the precise mechanisms linking obstructive sleep apnea (OSA) and cardiovascular disease (CVD) are unclear. Platelets are mediators of CVD risk and thrombosis and prior studies suggested associations of OSA and platelet activity. The aim of this study is to assess the link between OSA, platelet activity, and CVD-related risk factors. We studied the association of OSA-measures and platelet aggregation in participants dually enrolled in the SHHS (Sleep Heart and Health Study) and FHS (Framingham Heart Study). We applied linear regression models with adjustment for demographic and clinical covariates and explored interactions with OSA and CVD-related factors, including age, sex, body mass index, hypertension, OSA diagnosis (apnea-hypopnea index 4%≥5), and aspirin use. Our final sample was of 482 participants (60 years [14.00], 50.4% female). No associations were observed between apnea-hypopnea index 4% and platelet aggregation in the main sample. Stratified analysis revealed an association in aspirin users (n=65) for our primary exposure (apnea-hypopnea index 4%, β=0.523; P<0.001; n=65), and secondary exposures: hypoxic burden (β=0.358; P<0.001), minimum saturation (β=-0.519; P=0.026), and oxygen desaturation index 3% (β=74.672; P=0.002). No associations were detected in nonaspirin users (n=417). No associations were detected between OSA and platelet aggregation in a community sample. Our finding that OSA associates with increased platelet aggregation in the aspirin group, most of whom use it for primary prevention of CVD, suggests that platelet aggregation may mediate the adverse impact of OSA on vascular health in individuals with existing CVD risk, supporting further investigation.

Hydrogen Sulfide Promotes Platelet Autophagy via PDGFR-α/PI3K/Akt Signaling in Cirrhotic Thrombocytopenia.

The role of platelet autophagy in cirrhotic thrombocytopenia (CTP) remains unclear. This study aimed to investigate the impact of platelet autophagy in CTP and elucidate the regulatory mechanism of hydrogen sulfide (H2S) on platelet autophagy. Platelets from 56 cirrhotic patients and 56 healthy individuals were isolated for in vitro analyses. Autophagy markers (ATG7, BECN1, LC3, and SQSTM1) were quantified using enzyme-linked immunosorbent assay, while autophagosomes were visualized through electron microscopy. Western blotting was used to assess the autophagy-related proteins and the PDGFR/PI3K/Akt/mTOR pathway following treatment with NaHS (an H2S donor), hydroxocobalamin (an H2S scavenger), or AG 1295 (a selective PDGFR-α inhibitor). A carbon tetrachloride-induced cirrhotic BALB/c mouse model was established. Cirrhotic mice with thrombocytopenia were randomly treated with normal saline, NaHS, or hydroxocobalamin for 15 days. Changes in platelet count and aggregation rate were observed every three days. Cirrhotic patients with thrombocytopenia exhibited significantly decreased platelet autophagy markers and endogenous H2S levels, alongside increased platelet aggregation, compared to healthy controls. In vitro, NaHS treatment of platelets from severe CTP patients elevated LC3-II levels, reduced SQSTM1 levels, and decreased platelet aggregation in a dose-dependent manner. H2S treatment inhibited PDGFR, PI3K, Akt, and mTOR phosphorylation. In vivo, NaHS significantly increased LC3-II and decreased SQSTM1 expressions in platelets of cirrhotic mice, reducing platelet aggregation without affecting the platelet count. Diminished platelet autophagy potentially contributes to thrombocytopenia in cirrhotic patients. H2S modulates platelet autophagy and functions possibly via the PDGFR-α/PI3K/Akt/mTOR signaling pathway.

Improvement of skin wound healing by giant salamander skin mucus gel wrapped with bone marrow mesenchymal stem cells via affecting integrin family molecules.

Traditional bandages, gauze, and cotton balls are increasingly insufficient for addressing complex war injuries characterized by severe bleeding and diverse wound conditions. The giant salamander, a species of high medical value, secretes a unique mucus when stimulated, which has potential applications in wound care. Giant salamander skin mucus gel dressing wrapped with bone marrow mesenchymal stem cells (BMSCs-GSSM-gel) was prepared and validated. Skin wound injury of rabbit and mouse models were established. Hematoxylin and Eosin, Masson's trichrome, and Sirius red staining were performed. The platelet aggregation rate and coagulation items were measured. Transcriptome sequencing was performed to find potential differential expression genes. Preparation and characterization of BMSCs-GSSM-gel were performed, and BMSCs-GSSM-gel particles with a diameter of about 200 nm were obtained. BMSCs-GSSM-gel accelerated wound healing in both rabbit and mouse models. BMSCs-GSSM-gel significantly promoted hemostasis via increasing platelet aggregation rate and fibrinogen, but decreasing activated partial thromboplastin time, thrombin time, and prothrombin time. BMSCs-GSSM-gel treatment significantly impacted several genes associated with cell adhesion, inflammatory response, collagen-containing extracellular matrix, and the positive regulation of cell migration based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Integrin Subunit Beta 4 (ITGB4), Integrin Subunit Alpha 3 (ITGA3), and Laminin Subunit Beta 3 (LAMB3) might be involved in the wound healing process by BMSCs-GSSM-gel. We proved the BMSCs-GSSM-gel greatly improved the skin wound healing, and it might play a crucial role in the application fields of skin damage repair.

Abstract 1065: Age Increases Platelet Aggregation And Alters The Platelet Transcriptome

Introduction: Age is the strongest risk factor for cardiovascular diseases (CVD). Platelets contribute to CVD pathogenesis and may mediate, in part, the association between age and CVD. In this study, we investigated the impact of aging on platelet activity responses and the platelet transcriptome. Hypothesis: Increasing age is associated with increased platelet aggregation and altered transcriptome. Method: Adults ≥ 18 years without CVD, off aspirin or NSAIDS were stratified by age tertiles. Platelet activity was measured by flow cytometry and light transmission aggregometry in response to submaximal agonist stimulation with ADP, AA, collagen, and epinephrine. The association between age and platelet variables were adjusted for sex, race/ethnicity, BMI, hypertension, and diabetes. Differentially expressed transcripts by age were identified using the limma package, adjusted for sex and race/ethnicity. Results: Among 151 participants, median age was 52 years (IQR 38 to 61), 87 (58%) were female, 75 (50%) were non-White, and 27 (18%) were Hispanic. There was no association between platelet count and size with age. There was a significant association between platelet aggregation in response to multiple agonists and age in both unadjusted and adjusted analyses ( Table ). Using a general linear model, we identified 199 platelet transcripts significantly affected by age (P &lt;0.01, 119-positively, 80-negatively). Gene set enrichment analysis demonstrated upregulation of platelet activity pathways (platelet alpha granule [NES = 2.09, q = 0.0008], platelet activation [NES = 1.90, q = 0.002), and platelet aggregation [NES = 1.77, q = 0.03]) with increasing age. Conclusion: Age is independently associated with platelet aggregation in response to submaximal agonist stimulation, a finding supported by the enrichment of platelet activation pathways in the transcriptome. Future studies are needed to elucidate the mechanisms by which age increases platelet aggregation.

Cuproptosis and copper deficiency in ischemic vascular injury and repair.

Ischemic vascular diseases are on the rise globally, including ischemic heart diseases, ischemic cerebrovascular diseases, and ischemic peripheral arterial diseases, posing a significant threat to life. Copper is an essential element in various biological processes, copper deficiency can reduce blood vessel elasticity and increase platelet aggregation, thereby increasing the risk of ischemic vascular disease; however, excess copper ions can lead to cytotoxicity, trigger cell death, and ultimately result in vascular injury through several signaling pathways. Herein, we review the role of cuproptosis and copper deficiency implicated in ischemic injury and repair including myocardial, cerebral, and limb ischemia. We conclude with a perspective on the therapeutic opportunities and future challenges of copper biology in understanding the pathogenesis of ischemic vascular disease states.

Inhibiting MMP13 Attenuates Deep Vein Thrombosis in a Mouse Model by Reducing the Expression of Pdpn.

Matrix metalloproteinase 13 (MMP13) is an extracellular matrix protease that affects the progression of atherosclerotic plaques and arterial thrombi by degrading collagens, modifying protein structures and regulating inflammatory responses, but its role in deep vein thrombosis (DVT) has not been determined. The purpose of this study was to investigate the potential effects of MMP13 and MMP13-related genes on the formation of DVT. We altered the expression level of MMP13 in vivo and conducted a transcriptome study to examine the expression and relationship between MMP13 and MMP13-related genes in a mouse model of DVT. After screening genes possibly related to MMP13 in DVT mice, the expression levels of candidate genes in human umbilical vein endothelial cells (HUVECs) and the venous wall were evaluated. The effect of MMP13 on platelet aggregation in HUVECs was investigated in vitro. Among the differentially expressed genes, interleukin 1 beta, podoplanin (Pdpn), and factor VIII von Willebrand factor (F8VWF) were selected for analysis in mice. When MMP13 was inhibited, the expression level of PDPN decreased significantly in vitro. In HUVECs, overexpression of MMP13 led to an increase in the expression level of PDPN and induced platelet aggregation, while transfection of PDPN-siRNA weakened the ability of MMP13 to increase platelet aggregation. Inhibiting the expression of MMP13 could reduce the burden of DVT in mice. The mechanism involves downregulating the expression of Pdpn through MMP13, which could provide a novel gene target for DVT diagnosis and treatment.

Platelet Reactivity in the Exacerbation of Psoriasis.

Background: Psoriasis is a chronic, inflammatory, immune-mediated disease with a specific cutaneous presentation. Increased platelet aggregation has been observed in patients with extensive psoriatic lesions. The aim of this study was to evaluate the clinical factors affecting platelet reactivity in patients with an exacerbation of psoriasis. Methods: This was a prospective, single-center, observational study, enrolling patients hospitalized for an aggravation of psoriasis. Enrolled patients underwent single platelet function testing with light transmission aggregometry on the first morning of hospitalization. Results: 120 patients were enrolled in the study. Of the compared subgroups, women had higher maximal platelet aggregation (MPA) than men (77% vs. 72%; p = 0.03), and those with BMIs < 25 kg/m2 showed higher platelet reactivity compared to subjects with BMIs ≥ 25 kg/m2 (75% vs. 73%; p = 0.02). There was a positive correlation between MPA and platelet count (r = 0.27; p < 0.01), as well as C-reactive protein concentration (r = 0.20; p = 0.03), while a negative correlation was observed with total cholesterol (r = -0.24; p = 0.01) and triglycerides (r = -0.30; p < 0.01). A two-step analysis based on multidimensional models with random effects revealed that every increase in the platelet count by 103/μL led to an increase in MPA by 0.07% (R2 = 0.07; p < 0.01), and an increase in triglycerides' concentration by 1 mg/dL was related to a reduction in MPA by 0.05% (R2 = 0.07; p < 0.01). Conclusions: The increased platelet reactivity observed in patients with psoriasis appears to be multifactorial and related to several clinical and laboratory features. Further research is warranted to put these findings into a clinical perspective.

ATR1 A1166C (rs5186), FII G20210A (rs1799963), FV G1691A (rs6025), FXIII 97G > T (rs11466016) and MTHFR A1298C (rs1801131) polymorphisms and the risk of ST-elevation myocardial infarction in young Mexican individuals.

Previous studies had identified genetic variants associated with Myocardial Infarction, but results are inconclusive. We examined the association between FII G20210A (rs1799963), FV G1691A (rs6025), FXIII 97G > T (rs11466016), ATR1 A1166C (rs5186) and MTHFR A1298C (rs1801131) polymorphisms and ST elevation Myocardial Infarction in young Mexican individuals. We included a total of 350 patients with Myocardial Infarction <45 years old and 350 controls matched by age and gender. The polymorphisms were analyzed by PCR-RFLP using specific restriction enzymes. DNA fragments were separated by electrophoresis in 2% gel of agarose and visualized using SYBR green. The A1166C (p = 0.004) but not FXIII 97G > T (p = 0.19), G20210A (p = 0.32), G1691A (p = No significant) and A1298C (p = 0.21) polymorphisms were associated with increased risk for ST elevation Myocardial Infarction. Moreover, dyslipidemia, hypertension, smoking and family history of atherothrombotic disease were associated. We found that A1166C represented increased risk for ST elevation Myocardial Infarction. However, G20210A, G1691A, 97G > T, and A1298C were not associated. In addition, we had determined that Glu298Asp, PLA1/A2, TAFI Thr325Ile, ACE I/D, AGT M235T and PAI-1 4G/5G polymorphisms represented increased risk in the same group of patients. However, MTHFR C677T, AGT T174M, FV G1691A, TSP-1 N700S, MTHFR C677T and TAFI 174M polymorphisms were no associated. Our results suggest that in young patients with ST Myocardial Infarction, those polymorphisms could contribute to premature endothelial dysfunction, atherothrombosis, vasoconstriction, increased platelet aggregation, muscle cell migration and proliferation. Further studies are required to try to better assess gene-gene and gene-modifiable factors interaction.

Investigation of platelet activation and calcium store release by a topical hemostatic xerogel dressing for improved blood clotting

AbstractAdequate topical hemostatic dressings are required as first‐line approach for reduction of uncontrolled hemorrhage, a leading cause of mortalities. Platelets play a major role during blood clotting to prevent hemorrhage during injuries. Here, we demonstrate the mechanisms activated through protease activating receptor 1 (PAR1), a platelet membrane protein in response to a porous composite xerogel dressing incorporating SiNPs (size 122 ± 10 nm) and calcium (2.5 mM), characterized by scanning electron microscopy–energy dispersive x‐ray spectroscopy and Fourier transform infrared spectroscopy. The composite displayed 13.9‐fold improved blood clotting index in comparison to commercial dressing. The composite displayed increased platelet aggregation due to development of well‐formed pseudopodia as compared to bare xerogel, SFLLRN (a thrombin mimic), adenosine di‐phosphate (a platelet activator), and heparin (a thrombin inhibitor). Further, PAR1 gene was significantly upregulated in model A549 epithelial cell line (1.2‐fold) and human platelets (1.4‐fold). The composite enhanced calcium release and its extrusion in A549 cells. Upregulation of PAR1 on the platelet surface and calcium release are crucial for platelet shape change and aggregation. The data indicate that xerogel composite containing SiNPs and calcium enhanced blood clotting through activation of PAR1. Such dressings can provide a potential hemostatic solution to reduce blood loss, disability, and mortality during surgery and trauma care.

Impact of lipid emulsions in parenteral nutrition on platelets: a literature review.

Lipid emulsions are essential components of parenteral nutrition solutions that provide energy and essential fatty acids. The complexity of the formulations of lipid emulsions may lead to adverse outcomes such as platelet reactivity and changes in platelet aggregation and related coagulation. Platelets are responsible for haemostasis; they activate and demonstrate morphological changes upon extracellular factors to maintain blood fluidity and vascular integrity. Although parenteral nutrition lipid emulsions are generally found safe with regard to modulation of platelet activity, studies are still accumulating. Thus, this review aims to investigate platelet-related changes by parenteral nutrition lipid emulsions in human studies. Studies have pointed out patients at risk of bleeding and increased platelet aggregation responses due to the administration of lipid emulsions. Lipid emulsions may further benefit patients at high risk of thrombosis due to anti-thrombotic effects and should be cautiously used in patients with thrombocytopenia. The reported platelet-related changes might be associated with the fatty acid change in the plasma membranes of platelets following changes in platelet synthesis and plasma levels of eicosanoids. In conclusion, studies investigating platelets and parenteral nutrition should be supported to minimize the adverse effects and to benefit from the potential protective effects of parenteral nutrition lipid emulsions.

Increased Platelet Aggregation in Adults After Orthotopic Liver Transplantation Indicates Higher Probability of Early Postoperative Survival.

BACKGROUND Studies have shown that increased platelet aggregation in patients with decompensated cirrhosis indicates higher risk of further decompensation and death, but studies on the association between platelet aggregation function and early postoperative survival in orthotopic liver transplantation (OLT) patients are rare. We conducted a retrospective study to investigate whole-blood platelet aggregation during the perioperative period of OLT patients and its association with clinical outcomes. MATERIAL AND METHODS Adult patients who underwent OLT between January 1 and April 30, 2021 were retrospectively reviewed. Laboratory test results indicating primary hemostasis were analyzed. The generalized linear model was used to investigate the association between primary hemostasis parameters and survival. RESULTS A total of 256 patients were enrolled. The median platelet count (PLT) was 61.5 (39.5-106.3)×109/L before transplantation. The median MA value was 43.1 (34.5-56.2) mm. From the 1st to the 3rd day after transplantation, PLT and MA both indicated a significant decrease. Two weeks after transplantation, PLT rose to 143.0 (85.0-209.0)×10⁹/L, and the MA value rose to 56.7 (52.2-62.7) mm. On multivariate analysis, PLT at 1 week after transplantation (OR: 1.07; P=0.006) and MA value (OR: 1.12; P=0.003) were independently associated with outcome. The AUROC of the model combined with MA value, MELD score, and age was 0.945 (95% CI: 0.911-0.978). CONCLUSIONS The change in primary hemostasis during the early postoperative period of adult OLT is mainly characterized by the increase of platelet count and function 14 days after transplantation. Higher PLT was associated with higher survival at 14 days after transplantation, while a higher PLT ratio was associated with survival at 3 months after transplantation. Based on comprehensive consideration, the model combined with MA value, MELD score, and age more reliably indicated the associated with early survival after transplantation.

The use of thromboelastography and the functional tests with double local hypoxia of the upper limb to assess the risk of thromboembolism in patients undergoing surgery

The use of thromboelastography and the functional tests with double local hypoxia of the upper limb to assess the risk of thromboembolism in patients undergoing surgery

Soluble urokinase plasminogen activator receptor, platelet aggregation, and carotid plaque thickness in diabetes: A cross-sectional analysis

BackgroundSoluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker strongly linked with cardiovascular disease in diabetes. By investigating its association with platelet aggregation levels and carotid plaque thickness, we can potentially improve the characterization of cardiovascular pathophysiology in type 1 (T1D) and type 2 diabetes (T2D). MethodsSuPAR was measured post-hoc in plasma collected in two cross-sectional studies including 1) individuals with T1D and 2) individuals with T2D without known cardiovascular disease. Platelet aggregation was analyzed employing impedance aggregometry using the agonists arachidonic acid (ASPI), adenosine diphosphate (ADP), and thrombin receptor activating peptide-6 (TRAP). Carotid plaque thickness was assessed bilaterally, and the thickest plaque (cPTmax) was analyzed. Correlations and associations of suPAR with platelet aggregation and cPTmax were assessed with Pearson's R and linear regressions adjusted for sex, age, C-reactive protein, estimated glomerular filtration rate, and platelet levels (only for aggregation analysis). ASPI analyses were only performed in participant not receiving aspirin treatment. Standardized estimates with 95 % confidence intervals are presented. ResultsTwo-hundred eighty-three with T1D (mean age 55 years, 44 % women) and 493 individuals with T2D (mean age 65 years, 33 % women) were included. SuPAR levels were positively correlated to platelet aggregation in both T1D (ADP: R = 0.18, p = 0.003; ASPI R = 0.13, p = 0.026) and T2D (ADP R = 0.14, p = 0.002; ASPI R = 0.14, p = 0.017). In adjusted linear regressions higher SuPAR levels were associated with higher ADP induced platelet aggregation in both T1D (26 (8, 44) AU/min, p = 0.004) and T2D (22 (3, 42) AU/min, p = 0.025), while associations to the other agonists were not conclusive. Higher suPAR levels were associated with thicker cPTmax in T1D (0.19 (0.07, 0.32) mm, p = 0.003), but not in T2D (p = 0.94). ConclusionHigher levels of suPAR, an inflammatory generalized disease biomarker, were associated with increased platelet aggregation and thicker cPTmax, in type 1 diabetes. Similar associations with platelet aggregation were found in type 2 diabetes, but not for carotid plaque thickness. These results suggest distinct cardiovascular pathomechanisms in T1D and T2D, although prospective studies are needed to confirm these findings.

Abstract 17162: High Lp(a) is Associated With Activation of the Arachidonic Acid Pathway

Introduction: High lipoprotein(a) [Lp(a)] is associated with increased platelet aggregation, inflammation and cardiovascular events. Eicosanoids such as eicosapentaenoic acid (EPA) and arachidonic acid (AA) have anti- and pro-inflammatory effects, respectively. In this cross-sectional study, we explored the associations between eicosanoids, Lp(a), and oxidized phospholipids on apolipoprotein B (oxPL:apoB). Hypothesis: Increased platelet aggregation and inflammation associated with high Lp(a) levels may be due to relative EPA and AA levels. Methods: Consecutive outpatients with known Lp(a) levels seen in an outpatient cardiology practice between April 2021 to April 2023 underwent repeat testing for Lp(a) and measurement of OxPL:apoB, EPA and AA levels. OxPL:apoB was measured using chemiluminescent immunoassay. Fatty acid measurements were done via column chromatography/mass spectrometry. Lp(a), OxPL-apoB, EPA, and AA were log e -transformed to satisfy the assumption of normality. Results: We enrolled 238 patients with a mean age of 56.5 ± 13.5 years (46% being female, 69% white, 10% black, 14% Asian). Statin therapy was used in 66%, and mean LDL-C was 87.3 ± 47.5 mg/dL. Median (IQR) Lp(a), OxPL:apoB, AA, and AA:EPA ratio was 167.7 (57.3-233.5) nmol/L, 2.3 (1.2-3.9) nmol/L, 287.3 (234.8-350.2) ug/mL, and 10.3 (6.1-14.9), respectively. Lp(a) correlated with OxPL:apoB (r=0.48, p&lt;0.0001). In multivariate analysis adjusting for age, race, sex, hypertension, LDL-C, statin use and PCSK9 inhibitor use, log-Lp(a) was associated with AA (p=0.002) and log-AA:EPA (p=0.02), but not associated with log-EPA (p=0.19). LogOxPL:apoB was associated with log AA (p=0.03). Conclusion: Higher Lp(a) levels are associated with elevated AA levels, suggesting a pathway by which Lp(a) may contribute to increased platelet aggregation and inflammation in patients with high Lp(a).

Platelet Mitochondria Calcium Uniporter Regulates ITAM-Dependent Platelet Activation and Signaling

Introduction: The ability of platelets to multitask is critical to arrest bleeding after injury and for the development of arterial thrombosis, which underlies myocardial infarction and stroke. Platelet activation relies heavily on changes in cytoplasmic calcium flux. However, little is known on the role mitochondrial calcium flux directly plays in platelet activation. In other cells, release of calcium from intracellular stores results in calcium entry into channels located in the outer mitochondrial membrane. Once calcium enters the intermembrane space, entry into the mitochondrial matrix is regulated by a multimeric complex, composed of channel-forming subunits and regulatory elements called the mitochondrial calcium uniporter (MCU). MCU has been extensively studied in cardiac tissue where calcium flux through MCU is critical for regulating bioenergetics, ROS formation, and cytoplasmic calcium levels. As these processes are important for platelet activation, these studies would indicate mitochondrial calcium flux may regulate platelet activation. However, the role of MCU in platelet function and activation is poorly understood. Aim: The goals of the current study are 1) to examine the role of MCU and mitochondrial calcium flux in platelet function and 2) to establish if mitochondrial calcium regulates thrombosis. Methods: We generated a platelet-specific MCU-deficient mouse (MCU fl/fl-PF4-cre, KO) and compared them to littermate wild-type controls (MCU fl/fl, WT). Platelet function including activation, aggregation, and mitochondrial calcium flux in response to PAR4 activating peptide (PAR) and ADP (P2Y12), both GPCRs or to collagen (GPVI) and rhodocytin (CLEC-2), both ITAMs, were examined. In addition, we examined ex vivo platelet adhesion under arterial and venous shear to collagen and in vivo thrombosis using a ferric chloride carotid artery model. Results: Mice deficient inplatelet MCU were viable and fertile. In addition, platelet-specific MCU deletion did not alter platelet counts, mean platelet volume, or platelet half-life. MCU KO platelets had significantly reduced (p&amp;lt;0.05) GPVI and CLEC-2-dependent aIIbb3 activation and P-selectin expression while platelet activation in response to P2Y12 and PAR4 stimulation was unchanged. Consistent with our activation results, platelet aggregation was significantly reduced in response to collagen and rhodocytin (p&amp;lt;0.05) in MCU KO platelets, but not thrombin or ADP. MCU KO platelets adhered significantly less (p=0.0012) to collagen compared to MCU WT platelets under arterial and venous shear conditions. In vivo, MCU KO mice had longer occlusion time compared to the WT (p=0.0044). Mechanistically, mitochondrial calcium flux was significantly reduced (p&amp;lt;0.05) in MCU KO platelets compared to WT platelets after GPVI stimulation, but not PAR4 activation. Furthermore, mitochondrial reactive oxygen species (ROS) generation was significantly reduced in MCU KO platelets compared to WT platelets (p=0.0097) after GPVI-dependent activation while PAR4 activation induced no change in mitochondrial ROS. Mitochondrial ROS is known to regulate signaling in other cells. Consistent with this hypothesis, we observed a significant reduction in the ITAM signaling molecules pSyK (p=0.0084) and pPLCγ2 (p=0.012) in MCU KO platelets after GPVI stimulation. Furthermore, inhibiting mitochondrial ROS using MitoTempo, a specific mitochondrial ROS inhibitor, decreased aggregation (p=0.0004) as well as downstream signaling, including pSyk (p=0.0046) and pPLCγ2 (p=0.0493) in WT platelets when treated with a GPVI agonist. In parallel, treating MCU KO platelets with H 2O 2 to induce ROS production increased platelet aggregation (p=0.0036) after GPVI activation. Conclusion(s): Platelet MCU mediates platelet activation and thrombosis in an ITAM-dependent manner by regulating mitochondrial calcium flux and ROS generation as well as downstream ITAM signaling through GPVI and CLEC-2. Our data support a novel role for mitochondria and mitochondria calcium flux in regulating ITAM-dependent platelet activation and demonstrate platelet MCU as a novel anti-platelet target to reduce thrombosis

Aging Is Associated With Organ-Specific Alterations in the Level and Expression Pattern of von Willebrand Factor.

VWF (von Willebrand factor) is an endothelial-specific procoagulant protein with a major role in thrombosis. Aging is associated with increased circulating levels of VWF, which presents a risk factor for thrombus formation. Circulating plasma, cellular protein, and mRNA levels of VWF were determined and compared in young and aged mice. Major organs were subjected to immunofluorescence analyses to determine the vascular pattern of VWF expression and the presence of platelet aggregates. An in vitro model of aging, using extended culture time of endothelial cells, was used to explore the mechanism of age-associated increased VWF levels. Increased circulating plasma levels of VWF with elevated levels of larger multimers, indicative of VWF functional activity, were observed in aged mice. VWF mRNA and cellular protein levels were significantly increased in the brains, lungs, and livers but not in the kidneys and hearts of aged mice. Higher proportion of small vessels in brains, lungs, and livers of aged mice exhibited VWF expression compared with young, and this was concomitant with increased platelet aggregate formation. Prolonged culture of endothelial cells resulted in increased cell senescence that correlated with increased VWF expression; VWF expression was specifically detected in senescent cultured endothelial cells and abolished in response to p53 knockdown. A significantly higher proportion of VWF expressing endothelial cells in vivo exhibited senescence markers SA-β-Gal (senescence-associated β-galactosidase) and p53 in aged mouse brains compared with that of the young. Aging elicits a heterogenic response in endothelial cells with regard to VWF expression, leading to organ-specific increase in VWF levels and alterations in vascular tree pattern of expression. This is concomitant with increased platelet aggregate formation. The age-associated increase in VWF expression may be modulated through the process of cell senescence, and p53 transcription factor contributes to its regulation.

Mechanism of Buyang Huanwu Decoction in protecting ischemic myocardium by regulating platelet autophagy in rats with acute myocardial infarction

This study explored the effects of Buyang Huanwu Decoction(BYHWD) on platelet activation and differential gene expression after acute myocardial infarction(AMI). SD rats were randomly divided into a sham-operated group, a model group, a positive drug(aspirin) group, and a BYHWD group. Pre-treatment was conducted for 14 days with a daily oral dose of 1.6 g·kg~(-1) BYHWD and 0.1 g·kg~(-1) aspirin. The AMI model was established using the high ligation of the left anterior descending coronary artery method. The detection indicators included myocardial infarct size, heart function, myocardial tissue pathology, peripheral blood flow perfusion, platelet aggregation rate, platelet membrane glycoprotein CD62p expression, platelet transcriptomics, and differential gene expression. The results showed that compared with the sham-operated group, the model group showed reduced ejection fraction and cardiac output, decreased peripheral blood flow, and increased platelet aggregation rate and CD62p expression, and activated platelets. At the same time, TXB_2 content increased and 6-keto-PGF1α content decreased in serum. Compared with the model group, BYHWD increased ejection fraction and cardiac output, improved blood circulation in the foot and tail regions and cardiomyocytes arrangement, reduced myocardial infarct size and inflammatory infiltration, down-regulated platelet aggregation rate and CD62p expression, reduced serum TXB_2 content, and increased 6-keto-PGF1α content. Platelet transcriptome sequencing results revealed that BYHWD regulated mTOR-autophagy pathway-related genes in platelets. The differential gene expression levels were detected using real-time quantitative PCR. BYHWD up-regulated mTOR, down-regulated autophagy-related FUNDC1 and PINK genes, and up-regulated p62 gene expression. The results demonstrated that BYHWD could regulate platelet activation, improve blood circulation, and protect ischemic myocardium in AMI rats, and its mechanism is related to the regulation of the mTOR-autophagy pathway in platelets.

Initial platelet aggregation in the complex shear environment of a punctured vessel model

To analyze flow conditions and cellular behavior at the onset of a hemostatic response in the injury of a microneedle-induced vessel puncture, a combined in silico and in vitro platform is created. A cell-resolved blood flow model is utilized for in-depth flow profile and cell distribution analyses, and a novel punctured vessel flow chamber is set up to complement the simulations with the evaluation of platelet aggregation around the wound neck of the puncture. The respective setups of the platform are explained, and the results of both experiments and simulations with various puncture diameters and pressure drops are combined, providing detailed insight into the basic processes of platelet transport and aggregation in the wound area. A special emphasis of the simulation evaluation is put on the cell distributions and the magnitude of shear rate and elongational flow in the wound neck area, as well as downstream from the puncture. Additionally, possible implications of wound size and pressure difference on the hemostatic response are discussed. The simulations display asymmetric cell distributions between the proximal and distal sides of the wound neck in regard to the flow direction. The flow chamber with the puncture diameter closest to the simulated domains confirms this asymmetry by displaying increased platelet aggregation at the wound neck's distal side. The presented punctured vessel in silico and in vitro experimental setups offer a platform to analyze the hemostatic environment of a vessel injured by a puncture and might assist in identifying differentiating factors between primary hemostasis and arterial thrombosis.

ELEVATED PLATELET REACTIVITY IN PATIENTS WITH UNCONTROLLED HYPERTENSION: THE EFFECT OF CHA2DS2-VASC SCORE

Objective: Hypertension is associated with vascular and endothelial dysfunction that may result in a greater propensity for reactive platelets to cause thrombosis. Purpose: The aim of this study was to evaluate multiple platelet activation pathways in hypertensive patients with different level of blood pressure control and cardiovascular risk factors. Design and method: Thirty nine uncontrolled (office SBP &gt; 140 mmHg and ambulatory daytime SBP &gt;135 mmHg, 27 males, aged 58 ± 9 years) and 32 well controlled (office SBP &lt; 140 mmHg and ambulatory daytime SBP &lt; 135 mmHg, 21 males, aged 58 ± 8 years) essential hypertensive patients were included in the study. Twenty four healthy individuals (12 males, aged 53 ± 10 years) were served as control group. Blood samples were obtained before and 48 hours after the procedure and platelet aggregation was tested in platelet rich plasma after activation with arachidonic acid (AA), adenosine diphosphate ADP), collagen (Col), epinephrine (Epi) and ristocetin (Risto), by using AggRAM Platelet Aggregation Analyzer. Results: Hypertensive patients showed elevated platelet reactivity in all platelet activation pathways compared to normotensive group (AA: 88.8 ± 6.8% versus 79.5 ± 7.3%, ADP: 86.8±9.1% versus 71.5±7.7%, Col: 86.5 ± 5.7% versus 73.9 ± 6.7%, Epi: 92.6±5.4% versus 80.5 ± 5.7%, Risto: 93.8 ± 6.8% versus 79.9 ± 6.3%, p &lt;0.05 for all). Col, Epi and Risto platelet activation pathway showed a statistically significant increase in patients with uncontrolled hypertension compared to the group with well controlled hypertension (AA: 88.8 ± 6.1% versus 89.1 ± 4.1%, ADP: 89.8 ± 4.1% versus 87.5±4.7%, Col: 87.5±4.7% versus 81.9 ± 6.7%, Epi: 93.6 ± 4.4% versus 80.1 ± 5.7%, Risto: 94.8 ± 3.8% versus 80.9 ± 4.3%,). Notably, strong correlations were found between the Col platelet pathway activation and Risto platelet pathway activation and CHA2DS2-VASc score (r = 0.57, p &lt;0.001 and r = 0.61, p &lt;0.001, respectively) in hypertensive patients. Conclusions: Patients with uncontrolled hypertension showed elevated platelet reactivity. Patients with high CHA2DS2-VASc even without atrial fibrillation carry also a higher risk of thrombosis as indicated by the increased platelet aggregation under certain pathways of activation.

A Study on the Usage of Probiotics as a Safer Antipyretic

Most medicines and supplements which include probiotics have both expected clinical outcomes and unwanted side effects, which plays a major role when considering them as a mode of treatment. This review is an update about the advantages and disadvantages associated with the use of probiotics as part of a safe therapeutic armamentarium in health and other diseases. The advantages of probiotics run across multiple tissue systems in the body and a has a wide age spectrum. Probiotics also promote cardiovascular health, accelerate recovery from the condition of antibiotic-associated diarrhoea, decrease the effect of necrotizing enterocolitis with reduced inflammation, and accelerate the healing of the wound. Probiotics also contribute in treating chronic diseases for patients with type 2 diabetes as well as patients with HIV/AIDS. Moreover, probiotics play an important role in the treatment and/or prevention of cancers, especially those of the colon and bladder. On the other hand, probiotics also mimic serious threats to immunocompromised, genetically predisposed bodies, children, and newborns. Using probiotics may lead to bacteremia, fungemia, or septicemia when consumed more. Also, probiotics are found as a causative agent for pneumonia and abdominal abscesses, increase platelet aggregation, and promote antibiotic resistance among others. A huge number of microorganisms inhabit the human gut and consequently cause a compound network of the interactions of those organisms with each other and within the host cells, which stresses the requirement of extra caution in the use of probiotics as treatment therapy.