Levels Of Platelet Activation Research Articles

Thrombocytopenia in SFTS due to platelets with altered function undergoing cell death pathways.

Thrombocytopenia is the major clinical feature associated with the severity of SFTS, but the mechanism by which it occurs remains unclear. RNA transcriptome analyses were performed on platelets purified from SFTS patients and SFTSV-infected mice. The functions of differentially expressed genes (DEGs) in the platelets were characterized. ELISA, flow cytometry, and qRT-PCR were used to measure the levels of platelet activation, SFTSV infection in platelets, formation of neutrophil extracellular traps (NETs), transcription of DEGs and percent of platelets undergoing cell death. Enhanced neutrophil activation and interferon (IFN) signaling involved in the viral life cycle were common platelet responses in SFTS, which may consume increasing numbers of platelets. Other functional changes may be associated with different outcomes of SFTS. SFTSV infection led to platelet destruction by pyroptosis, apoptosis, necroptosis, and autophagy. In contrast to SFTS patients, platelets in SFTSV-infected mice mainly play a role in adaptive immunity, and platelet death was not as severe as in humans. The altered functions of platelets, such as mediating leukocyte activation and undergoing cell death, contribute to thrombocytopenia in SFTS patients. The different mechanisms of thrombocytopenia in mice, suggest that platelet functions should be considered in experimental animal models.

Effect of veno-arterial extracorporeal membrane oxygenation lower-extremity cannulation on intra-arterial flow characteristics, oxygen content, and thrombosis risk

PurposeThis study aimed to investigate the effects of lower-extremity cannulation on the intra-arterial hemodynamic environment, oxygen content, blood damage, and thrombosis risk under different levels of veno-arterial (V-A) ECMO support. MethodsComputational fluid dynamics methods were used to investigate the effects of different levels of ECMO support (ECMO flow ratios supplying oxygen-rich blood 100–40 %). Flow rates and oxygen content in each arterial branch were used to determine organ perfusion. A new thrombosis model considering platelet activation and deposition was proposed to determine the platelet activation and thrombosis risk at different levels of ECMO support. A red blood cell damage model was used to explore the risk of hemolysis. ResultsOur study found that partial recovery of cardiac function improved the intra-arterial hemodynamic environment, with reduced impingement of the intra-arterial flow field by high-velocity blood flow from the cannula, a flow rate per unit time into each arterial branch closer to physiological levels, and improved perfusion in the lower extremities. Partial recovery of cardiac function helps reduce intra-arterial high shear stress and residence time, thereby reducing blood damage. The overall level of hemolysis and platelet activation in the aorta decreased with the gradual recovery of cardiac contraction function. The areas at high risk of thrombosis under V-A ECMO femoral cannulation support were the aortic root and the area distal to the cannula, which moved to the descending aorta when cardiac function recovered to 40–60 %. However, with the recovery of cardiac contraction function, hypoxic blood pumped by the heart is insufficient in supplying oxygen to the front of the aortic arch, which may result in upper extremity hypoxia. ConclusionWe developed a thrombosis risk prediction model applicable to ECMO cannulation and validated the model accuracy using clinical data. Partial recovery of cardiac function contributed to an improvement in the aortic hemodynamic environment and a reduction in the risk of blood damage; however, there is a potential risk of insufficient perfusion of oxygen-rich blood to organs.

Impact of rise and fall phases of shear on platelet activation and aggregation using microfluidics.

Blood flow disorders are often the result of the non-physiological narrowing of blood arteries caused by atherosclerosis and thrombus. The blood then proceeds through rising-peak-decreasing phases as it passes through the narrow area. Although abnormally high shear is known to activate platelets, the shear process that platelets undergo in small arteries is complex. Thus, understanding how each shear phase affects platelet activation can be used to improve antiplatelet therapy and decrease the risk of side effects like bleeding. Blood samples were sheared (68.8 ms,5200s-1) in vitro by the microfluidic technique, and platelet activation levels (P-selectin and integrin αIIbβ3) and von Willebrand factor (vWF) binding to platelets were analyzed by flow cytometry. Post-stenosis platelet aggregation was dynamically detected using microfluidic technology. We studied TXA2, P2Y12-ADP, and integrin αIIbβ3-fibrinogen receptor pathways by adding antiplatelet drugs, such as acetylsalicylic acid (ASA, an active ingredient of aspirin that inhibits platelet metabolism), ticagrelor (hinders platelet activation), and tirofiban (blocks integrin αIIbβ3 receptor) in vitro, respectively, to determine platelet activation function mediated by transient non-physiological high shear rates. We demonstrated that platelets can be activated under transient pathological high shear rates. The shear rise and fall phases influenced shear-induced platelet activation by regulating the binding of vWF to platelets. The degree of platelet activation and aggregation increased with multiple shear rise and fall phases. ASA did not inhibit shear-mediated platelet activation, but ticagrelor and tirofiban effectively inhibited shear-mediated platelet activation. Our data demonstrated that the shear rise and fall phases play an important role in shear-mediated platelet activation and promote platelet activation and aggregation in a vWF-dependent manner. Blocking integrin αIIbβ3 receptor and hindering P2Y12-ADP were beneficial to reducing shear-mediated platelet activation.

The Effect of Leukocyte Removal and Matrix Metalloproteinase Inhibition on Platelet Storage Lesions.

The reasons for unfavorable changes in platelet concentrate (PC) quality during storage are not fully understood yet. We aimed to evaluate whether leukocytes and matrix metalloproteinases (MMPs) lead to a decrease in the quality of PCs and examine whether MMP inhibition will slow down the platelets' aging. Nine PCs were divided into three parts: (1) leukocyte-depleted (F) PCs, (2) PCs with no additional procedures (NF), and (3) PCs with the addition of an MMP inhibitor-doxycycline (D). Each PC was stored for 144 h, and a sample for testing was separated from each part on the day of preparation and after 24, 48, 72 and 144 h of storage. Blood morphological analysis, platelet aggregation, and the expression of activation markers were evaluated. MMP-2 and MMP-9 concentration, activity, and gene expression were assessed. Platelet aggregation decreased, and platelet activation marker expression increased during the storage. D concentrates showed the lowest level of platelet activation. In turn, leukocyte-depleted PCs showed the highest level of platelet activation in general. MMP-9 platelet activity was higher in leukocyte-containing concentrates at the end of the storage period. We concluded that the filtration process leads to a higher platelet activation level. The presence of doxycycline in PCs reduces the expression of the activation markers as compared to leukocyte-depleted concentrates.

Multi-Method Investigation of Blood Damage Induced By Blood Pumps in Different Clinical Support Modes.

To investigate the effects of blood pumps operated in different modes on nonphysiologic flow patterns, cell and protein function, and the risk of bleeding, thrombosis, and hemolysis, an extracorporeal blood pump (CentriMag) was operated in three clinical modalities including heart failure (HF), venous-venous (V-V) extracorporeal membrane oxygenation (ECMO), and venous-arterial (V-A) ECMO. Computational fluid dynamics (CFD) methods and coupled hemolysis models as well as recently developed bleeding and thrombosis models associated with changes in platelet and von Willebrand factor (vWF) function were used to predict hydraulic performance and hemocompatibility. The V-A ECMO mode had the highest flow losses and shear stress levels, the V-V ECMO mode was intermediate, and the HF mode was the lowest. Different nonphysiologic flow patterns altered cell/protein morphology and function. The V-A ECMO mode resulted in the highest levels of platelet activation, receptor shedding, vWF unfolding, and high molecular weight multimers vWF (HMWM-vWF) degradation, leading to the lowest platelet adhesion and the highest vWF binding capacity, intermediate in the V-V ECMO mode, and opposite in the HF mode. The V-A ECMO mode resulted in the highest risk of bleeding, thrombosis, and hemolysis, with the V-V ECMO mode intermediate and the HF mode lowest. These findings are supported by published experimental or clinical statistics. Further studies found that secondary blood flow passages resulted in the highest risk of blood damage. Nonphysiologic blood flow patterns were strongly associated with cell and protein function changing, blood damage, and complications.

Investigation of the role of von Willebrand factor in shear-induced platelet activation and functional alteration under high non-physiological shear stress.

von Willebrand factor (vWF) plays a crucial role in physiological hemostasis through platelet and subendothelial collagen adhesion. However, its role in shear-induced platelet activation and functional alteration under non-physiological conditions common to blood-contacting medical devices (BCMDs) is not well investigated. Fresh healthy human blood was treated with an anti-vWF antibody to block vWF-GPIbα interaction. Untreated blood was used as a control. They were exposed to three levels of non-physiological shear stress (NPSS) (75, 125, and 175 Pa) through a shearing device with an exposure time of 0.5 s to mimic typical shear conditions in BCMDs. Flow cytometric assays were used to measure the expression levels of PAC-1 and P-Selectin and platelet aggregates for platelet activation and the expression levels of GPIbα, GPIIb/IIIa, and GPVI for receptor shedding. Collagen/ristocetin-induced platelet aggregation capacity was characterized by aggregometry. The levels of platelet activation and aggregates increased with increasing NPSS in the untreated blood. More receptors were lost with increasing NPSS, resulting in a decreased capacity of collagen/ristocetin-induced platelet aggregation. In contrast, the increase in platelet activation and aggregates after exposure to NPSS, even at the highest level of NPSS, was significantly lower in treated blood. Nevertheless, there was no notable difference in receptor shedding, especially for GPIIb/IIIa and GPVI, between the two blood groups at the same level of NPSS. The block of vWF exacerbated the decreased capacity of collagen/ristocetin-induced platelet aggregation. High NPSS activates platelets mainly by enhancing the vWF-GPIbα interaction. Platelet activation and receptor shedding induced by high NPSS likely occur through different pathways.

Evaluation of Platelet and Clotting Parameters in Hematologic Malignancies and Hematopoietic Stem Cell Transplantation Patients with Candidemia

1.Backgroud In recent years, the number and proportion of deaths from fungal infections have increased year by year. The fatality rate of fungemia is about 0.4 per 100 000 [Pfaller MA, et al. Clin Microbiol Rev. 2007]. Chemotherapy can effectively treat hematological malignancies. Data from multi-center studies in China show that the overall mortality rate of patients receiving chemotherapy for hematological malignancies is only 1.5%, and the mortality rate of patients with clinically diagnosed invasive fungi is as high as 11.7% [ Sun Y, et al. Tumor Biol, 2015]. The surveillance data of China Hospital Invasive Fungal Disease Surveillance Network from 2015 to 2017 showed that Candida albicans was the most common pathogen among 4 010 Candida strains isolated from patients with candidemia from 77 hospitals in China [Xiao M, et al. J Infect Dis, 2020]. 2.Methods We conducted a retrospective study that collected relevant clinical information from 34 hematologic malignancies and hematopoietic stem cell transplantation (HSCT) patients with candidemia between 2017 to 2022 in Hematology Hospital, Chinese Academy of Medical Sciences. The blood specimens of patients suspected to have candidemia were collected and cultured. After diagnosis, they were regarded as the candidemia group, and 107 healthy people were selected as the control group. Candidemia is classified as invasive or non-invasive according to whether it involves tissues or organs damage. Blood routine and clotting related tests were performed at the Clinical Laboratory Center of Hematology Hospital, Chinese Academy of Medical Sciences. 3.Results 3.1 General Characteristics of the Study Subjects A total of 34 hematologic malignancies and HSCT patients with candidemia were recruited. Of these 34 patients, 28 were male and 6 were female. Meanwhile, 107 healthy people were recruited as control group. The characteristics of two groups are presented in Table 1. 3.2 Hematologic malignancies and HSCT patients with abnormal blood routine are at increased risk of candidemia Hematologic malignancies and HSCT patients with candidemia present as lower white blood cell count, lower red blood cell count, higher lymphocyte ratio, lower lymphocyte count, lower monocyte count, lower neutrophil count and ratio, and lower NEU/PLT compared with control group. 3.3 Candidemia cause platelet activation in hematologic malignancies and HSCT patients The PLT and PCT of hematologic malignancies and HSCT patients with candidemia were significantly lower than control group. Meanwhile, MPV and P-LCR were higher than control group. It revealed that hematologic malignancies and HSCT patients with candidemia may present with platelet activation, while PLT and PCT level were low in this group. 3.4 Invasive candidemia can cause a decrease in platelets and an increase in MPV/PLT Furthermore, we found that PLT level was lower and MPV/PLT level was higher in hematologic malignancies and HSCT patients with invasive candidemia than hematologic malignancies and HSCT patients with non-invasive candidemia. 3.5 Candidemia can cause coagulation dysfunction in hematologic malignancies and HSCT patients Hematologic malignancies and HSCT patients with candidemia had coagulation dysfunction symptoms such as prolonged PT and APTT, reduced antithrombin III activity, and high INR. 3.6 Candidemia can cause hyperfibrinolysis in hematologic malignancies and HSCT patients Meanwhile, hematologic malignancies and HSCT patients with candidemia showed reduced TT, increasing fibrinogen, fibrinogen degradation products, and D-Dimer. 4.Conclusion In conclusion, we demonstrated for the first time that decreasing platelet count and activated platelet function in hematologic malignancies and HSCT patients with candidemia. Invasive candidemia may cause lower platelet count and more activated platelet function in hematologic malignancies and HSCT patients. At the same time, we found that candidemia can cause coagulation dysfunction and hyperfibrinolysis in hematologic malignancies and HSCT patients. We hope that our study can provide a new perspective on the cognition and diagnosis of hematologic malignancies and HSCT patients with candidemia.

High-Fat Diet Enhances Platelet Activation and Is Associated with Proprotein Convertase Subtilisin Kexin 9: An Animal Study.

Platelet activation and proprotein convertase subtilisin kexin 9 (PCSK9) play pivotal roles in the progression of atherosclerosis to cardiovascular events. It has been reported that hyperlipidemia, a well-documented risk factors for cardiovascular diseases, tends increase platelet activation and PCSK9 expression. However, little is known about this specific mechanism, particularly how nutrition affects platelet activation and PCSK9 levels in hyperlipidemia conditions. This study aimed to assess how a high-fat diet influences platelet activation, its association with PCSK9, and the effects on blood pressure in an animal model. Here, male Wistar rats were divided into four groups, subjected to different high-fat diets for ten weeks with varying nutrient components. The results showed that high-fat diet-induced hypercholesterolemia and hypertriglyceridemia significantly increased the plasma levels of β-thromboglobulin (β-TG), p-selectin, and platelet factor 4 (PF-4). The blood pressure readings were also elevated post high-fat diet induction. Interestingly, the group with the highest percentage of saturated fatty acid and trans-fat exhibited the highest PCSK9 levels, along with the highest increase in plasma cholesterol, triglycerides, and platelet activation parameters. These findings confirm that high-fat diet-induced hypercholesterolemia and hypertriglyceridemia stimulate platelet activity and PCSK9 levels. Moreover, our results suggest that PCSK9, implicated in hypercholesterolemia and hypertriglyceridemia, may synergistically mediate platelet hyperactivity, aligning with clinical studies. Notably, our results highlight the association between a high-fat diet and PCSK9, providing insights for drug discovery targeting platelet activation in atherosclerosis-induced cardiovascular diseases.

Evaluating the impact of transient shear stress on platelet activation, adhesion, and aggregation with microfluidic chip technique.

When nonphysiological stenosis occurs, the transient high shear stress formed in vessels increases the risk of thrombosis and is a potential factor for cardiovascular diseases. But the platelet adhesion and aggregation behavior at nonphysiological post-stenosis and its affecting factors are not fully understood yet. In this experiment, platelet aggregation on collagen and fibrinogen at different shear stresses and different hematocrits were observed by microfluidic technology. Platelet activation (P-selectin, glycoprotein IIb/IIIa) and monocyte-platelet aggregate (MPA) levels under different shear stresses were analyzed by flow cytometry. On fibrinogen, platelets aggregate more at higher shear stress conditions. While on collagen, it becomes more difficult for platelets to form stable aggregation at higher shear stress conditions. If platelets adhere initially at low shear stress, stable platelet aggregation can be formed at subsequent high shear stress. Moreover, when the shear stress increases, platelet activity markers (P-selectin, glycoprotein IIb/IIIa and MPAs) increase significantly. Hematocrit affects the degree of platelet aggregation, and the influence of hematocrit is obvious at high shear stress. Transient high shear stress (46 ms) can effectively activate platelets. Platelet aggregation behavior was different for coated fibrinogen and collagen protein. Stable platelet adhesion at post-stenosis is more dependent on fibrinogen and platelet aggregation is stable on both fibrinogen and collagen. Hematocrit can significantly affect the formation of platelet aggregation.

Effect of pathological high shear exposure time on platelet activation and aggregation.

Circulating platelets are sometimes exposed to high shear rate environments due to vascular stenosis, and the effect of transiently elevated pathological high shear rates on platelet activation and aggregation function has not been clarified. The aim of this study was to investigate the effect of pathological high shear rate (8302s-1) exposure time (3.16-25.3 ms) on platelet activation and aggregation function. In addition, by adding active ingredients of antiplatelet drugs such as ASA (an active ingredient of aspirin), Ticagrelor, Tirofiban and GP1BA (platelet membrane protein GPIb inhibitor) in vitro, we studied TXA2, P2Y12-ADP, GPIIb/IIIa-fibrinogen and GPIb /IX/V-vWF receptor pathways to determine platelet activation function mediated by pathological high shear rate. In this study, we designed a set of microfluidic chips with stenosis lengths of 0.5 mm, 1 mm, 2 mm, 3 mm, and 4 mm, all with 80% stenosis, to generate pathological high shear forces that can act at different times. The whole blood flowing through the microchannels was collected by perfusion of sodium citrate anticoagulated whole blood at a physiological arterial shear rate (1500 s-1), and the expression levels of platelet surface activation markers (P-selectin and GP IIb/IIIa) and the degree of platelet aggregation were analyzed by flow cytometry; platelet aggregation patterns were observed by microscopic examination of blood smears. The results showed that shearing significantly increased platelet activation and aggregation levels compared to un-sheared whole blood, and the activation and aggregation levels increased with increasing duration of pathological high shear rate. In vitro inhibition studies showed that ASA barely inhibited the expression of P-selectin and PAC-1 on the platelet surface; Ticagrelor effectively inhibited the expression of both P-selectin and PAC-1; Tirofiban significantly inhibited the expression of PAC-1 on the platelet surface and slightly inhibited the expression of P-selectin; GP1BA significantly inhibited the expression of both. Our results suggest that transient pathological high shear rate (8302s-1) exposure can induce platelet activation in a time-dependent manner; however, the mechanism is more complex and may be due to the following reasons: transient elevated pathological high shear rate activates platelets through the GPIb/IX/V-vWF receptor pathway, and after platelet activation, its surface membrane protein GPIIb/IIIa receptors activate platelets through fibrinogen to form platelet-platelet aggregates, and further activation of active substances such as ADP and TXA2 released by platelet alpha particles, which contribute to the formation of irreversible platelet aggregation.

New potential biomarkers for early chronic kidney disease diagnosis in patients with different glucose tolerance status.

The purpose of the present study was to investigate the role of oxidative stress, platelet activation, and endocan levels in renal dysfunction in normal glucose tolerance (NGT) patients with 1-h plasma glucose values ≥155 mg/dl (NGT ≥ 155), compared to NGT < 155, impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) newly diagnosed subjects. We enlisted 233 patients subjected to an oral glucose tolerance test (OGTT). The serum levels of platelet activation (glycoprotein VI and sP-selectin), oxidative stress biomarkers (8-isoprostane and Nox-2), and endocan were evaluated using an ELISA test. Among NGT < 155 patients and the T2DM group, there was a statistically significant increase in 8-isoprostane (p < 0.0001), Nox-2 (p < 0.0001), glycoprotein VI (p < 0.0001), and sP-selectin (p < 0.0001) serum levels. Higher serum endocan levels were found with the worsening of metabolic profile (p < 0.0001); specifically, NGT ≥ 155 patients presented higher serum endocan values when compared to NGT < 155 patients (p < 0.0001). From the multivariate linear regression analysis, 1-h glucose resulted in the major predictor of estimated glomerular filtration rate (e-GFR) justifying 23.6% of its variation (p < 0.0001); 8-isoprostane and Nox-2 added respectively another 6.0% (p < 0.0001) and 3.2% (p = 0.001). Our study confirmed the link between 1-h post-load glucose ≥155 mg/dl during OGTT and the possible increased risk for chronic kidney disease (CKD) in newly diagnosed patients. The novelty is that we demonstrated a progressive increase in oxidative stress, platelet activation, and serum endocan levels with the worsening of metabolic profile, which becomes evident early during the progression of CKD.

The platelet transcriptome and proteome in Alzheimer's disease and aging: an exploratory cross-sectional study.

Introduction: Alzheimer's disease (AD) and aging are associated with platelet hyperactivity. However, the mechanisms underlying abnormal platelet function in AD and aging are yet poorly understood. Methods: To explore the molecular profile of AD and aged platelets, we investigated platelet activation (i.e., CD62P expression), proteome and transcriptome in AD patients, non-demented elderly, and young individuals as controls. Results: AD, aged and young individuals showed similar levels of platelet activation based on CD62P expression. However, AD and aged individuals had a proteomic signature suggestive of increased platelet activation compared with young controls. Transcriptomic profiling suggested the dysregulation of proteolytic machinery involved in regulating platelet function, particularly the ubiquitin-proteasome system in AD and autophagy in aging. The functional implication of these transcriptomic alterations remains unclear and requires further investigation. Discussion: Our data strengthen the evidence of enhanced platelet activation in aging and provide a first glimpse of the platelet transcriptomic changes occurring in AD.

Antiplatelet drugs do not protect from platelet-leukocyte aggregation in coronary artery disease

BackgroundDespite advances in cardiovascular medicine, coronary artery disease (CAD) remains a leading cause of mortality. Among the pathophysiological features of this condition, platelet-leukocyte aggregates (PLAs) require further attention, either as diagnostic/prognostic disease markers or as potential interventional targets. ObjectivesIn this study, we characterized PLAs in patients with CAD. Primarily, we investigated the association of PLA levels with CAD diagnosis. In addition, the basal levels of platelet activation and degranulation were assessed in patients with CAD and controls, and their correlation with PLA levels was analyzed. Finally, the effect of antiplatelet treatments on circulating PLA numbers, basal platelet activation, and degranulation was studied in patients with CAD. MethodsParticipants were recruited at the Department of Cardiology of the University Heart and Vascular Centre Hamburg Eppendorf. Among patients admitted with severe chest pain, the diagnosis of CAD was made angiographically, and patients without CAD were used as controls. PLAs, platelet activation, and platelet degranulation were assessed by flow cytometry. ResultsCirculating PLAs and basal platelet degranulation levels were significantly higher in patients with CAD than in controls. Surprisingly, there was no significant correlation between PLA levels and platelet degranulation (or any other measured parameter). In addition, patients with CAD on antiplatelet therapy did not display lower PLA or platelet degranulation levels compared with those in controls. ConclusionOverall, these data suggest a mechanism of PLA formation that is independent of platelet activation or degranulation and highlights the inefficiency of current antiplatelet treatments for the prevention of basal platelet degranulation and PLA formation.

The rate of platelet activation determines thrombus size and structure at arterial shear

BackgroundThe response of platelets to activating stimuli and pharmaceutical agents varies greatly within the normal population. Current platelet function tests are used to measure end-point levels of platelet activation without taking the speed at which platelets activate into account, potentially missing vital metrics to characterize platelet reactivity. ObjectivesTo identify variability, to agonists and among individuals, in platelet activation kinetics and assess the impact of this on thrombus formation. MethodsWe have developed a bespoke real-time flow cytometry assay and analysis package to measure the rate of platelet activation over time using 2 parameters of platelet activation, fibrinogen binding and P-selectin exposure. ResultsThe rate of platelet activation varied considerably within the normal population but did not correlate with maximal platelet activation, demonstrating that platelet activation rate is a separate and novel metric to describe platelet reactivity. The relative rate of platelet response between agonists was strongly correlated, suggesting that a central control mechanism regulates the rate of platelet response to all agonists. ConclusionFor the first time, we have shown that platelet response rate corresponds to thrombus size and structure, wherein faster responders form larger, more densely packed thrombi at arterial, but crucially not venous, shear. We have demonstrated that the rate of platelet activation is an important metric in stratifying individual platelet responses and will provide a novel focus for the design and development of antiplatelet therapy, targeting high-shear thrombosis without exacerbating bleeding at low shear.

The Combined Treatment of Glutathione Sodium Salt and Ascorbic Acid for Preventing Contrast-Associated Acute Kidney Injury in ST-Elevation Myocardial Infarction Patients Undergoing Primary PCI: A Hypothesis to Be Validated.

The occurrence of Contrast-Associated Acute Kidney Injury (CA-AKI) in patients with ST-Elevation Myocardial Infarction (STEMI) has a negative impact on the length of hospital stay and mortality. Reactive Oxygen Species (ROS) release, along with vasoconstriction and hypoperfusion, play a key role in its development. To date, there is still no validated prophylactic therapy for this disease. The use of antioxidants, based on experimental and clinical studies, looks promising. Taking into consideration previous literature, we speculate that an early, combined and prolonged intravenous administration of both Glutathione (GSH) and ascorbic acid in STEMI patients undergoing primary Percutaneous Coronary Intervention (pPCI) may be of value in counteracting the occurrence of CA-AKI. We aimed at evaluating this hypothesis by applying a multicenter research protocol, using a double-blind randomized, placebo-controlled trial design. The primary endpoint will be to test the efficacy of this combined antioxidant therapy in reducing the occurrence of renal damage, in patients with acute myocardial infarction treated with pPCI. Furthermore, we will investigate the effect of the study compounds on changes in oxidative stress markers and platelet activation levels through bio-humoral analyses.

Intravenous immunoglobulins ameliorate thrombin-related platelet functions in childhood immune thrombocytopenia.

Childhood immune thrombocytopenia (ITP) is an acquired haematological disorder characterized by low platelet counts, with a disease course which is usually benign and self-limiting within 3-12 months. An estimated 28%, however, continue to develop chronic ITP and may experience bleeding symptoms and an impaired quality of life. Treatment options in case of severe bleedings include corticosteroids, anti-D or intravenous immunoglobulins (IVIg). The general working mechanism of IVIg remains unresolved and a matter of debate. Schmugge et al now identify that IVIg may have the ability to improve thrombin-induced platelet activation and enhance thrombin generation in a prospective study of 23 children with primary ITP, demonstrating that besides increasing platelet counts IVIg can be efficacious on the level of thrombin-induced platelet activation and coagulation support. Commentary on: Schmugge et al. IVIg treatment increases thrombin activation of platelets and thrombin generation in paediatric patients with immune thrombocytopenia. Br J Haematol 2023;201:1209-1219.

Single-cell analysis of platelets from patients with periodontitis and diabetes

BackgroundBlood platelets are known to play a role in the development of atherosclerotic disease, thrombi, and hemostasis. Investigation of blood platelet transcriptome could provide evidence of disorders that increase vulnerability to cardiovascular disease. However, research on the molecular insights of platelet activation in patients with periodontitis and patients with periodontitis and type 2 diabetes mellitus (DM) is still lacking. ObjectivesIn this study, we analyzed expression in blood platelets from patients with periodontitis and patients with concurrent periodontitis and DM to examine the transcriptomic profile of platelets induced by periodontitis and the modifying effects of DM. MethodsWe obtained the transcriptional profiles of blood platelets from 11 healthy donors, 10 patients with periodontitis, and 6 patients with periodontitis and DM using single-cell RNA sequencing. The biological processes and coexpressed modules of transcriptionally altered genes were further explored. ResultsBoth the patients with periodontitis and DM and those with periodontitis without DM showed higher levels of platelet activation and coagulation signals than the healthy individuals. Platelets from the patients with periodontitis had higher expression levels of genes for RHO GTPase effectors, whereas platelets from the patients with periodontitis and DM demonstrated higher expression of genes involved in oxidative phosphorylation and cellular responses to stress than those from the controls. However, compared with the patients with only periodontitis, those with periodontitis and DM presented a lower expression level of genes for hemostasis and platelet receptors. ConclusionThese results suggest that periodontitis contributes to establishment of blood coagulation via platelet dysregulation, whereas the comorbidities of patients with periodontitis and DM impair the components of platelets, thus preventing normal functions.

Evaluation of Platelet Parameters in Patients With Secondary Failure of Platelet Recovery and Cytomegalovirus Infection After Hematopoietic Stem Cell Transplantation.

To investigate the clinical significance of changes in platelet parameters in patients with secondary failure of platelet recovery (SFPR) and cytomegalovirus (CMV) infection after hematopoietic stem cell transplantation (HSCT). In this retrospective study, 79 patients who had undergone allogeneic HSCT (allo-HSCT), including 40 patients with SFPR and 39 patients without SFPR, were recruited. The evaluated parameters were platelet count (PLT), plateletcrit (PCT), platelet-large cell ratio (P-LCR), mean platelet volume (MPV), platelet distribution width (PDW), the incidence of CMV infection after allo-HSCT, and the correlation of SFPR and CMV infection in patients who had undergone allo-HSCT. The control group included 107 healthy donors. The SFPR group had significantly lower megakaryocyte counts, PLT, and PCT and significantly higher P-LCR, MPV, and PDW than the healthy donor and non-SFPR groups. The incidence of CMV infection was higher in SFPR patients than in non-SFPR patients. Among the patients with SFPR, P-LCR, MPV, and PDW were lower in those with CMV DNA >8000 copies/mL than in those with CMV DNA <8000 copies/mL (P < .05 for all); the CMV viral load was slightly negatively correlated with MPV (P = .0297) and P-LCR (P = .0280). We demonstrate for the first time that the level of platelet activation in SFPR patients, which was closely related to CMV infection, was higher than that in that in non-SFPR patients, and higher CMV load was associated with the inhibition of platelet activation.

The effects of glucocorticoid plus intravenous immunoglobulin (IVIG) vs IVIG alone on platelet activation in children with Kawasaki disease.

Even though intravenous immunoglobulin (IVIG) is a current treatment for Kawasaki disease (KD), 10-20% of patients require additional therapy. This study seeks to investigate the therapeutic effects of glucocorticoids plus IVIG on KD and to ascertain the subsequent effect on platelet activation during the acute phase. A total of 32 children with KD were randomly classified into two groups: the experimental group (16 cases) and the control group (16 cases). The control group was exposed to IVIG (2 g/kg), whereas children in the experimental group were treated with IVIG (2 g/kg) + glucocorticoid. Peripheral venous blood samples were obtained from all participants before treatment as well as three days post-treatment to test platelet activation levels with procaspase activating compound-1 (PAC-1) antibody, Toll-like receptor 4 (TLR4), interleukin-6 (IL- 6), tumor necrosis factor-α (TNF-α), procalcitonin (PCT), and C-reactive protein (CRP). Fever duration posttreatment was documented for both groups. Additionally, the coronary arteries in both groups were evaluated during three months of treatment. After treatment, the experimental group had remarkably lower levels of TNF-α, CRP, PCT, IL-6, PAC- 1, and TLR4 relative to the control group. The fever persistence rate was considerably elevated in the control group compared to the experimental group (log-rank, P=0.024). In addition, the z-score of coronary artery size dropped after IVIG + glucocorticoids treatment compared to the control group, although this difference was not significant. The IVIG + glucocorticoids can quickly mitigate the inflammatory response and platelet activation. Moreover, it can also improve clinical symptoms in children with KD.

93 EFFECT OF SACUBITRIL/VALSARTAN ON ENDOTHELIAL DYSFUNCTION AND ARTERIAL STIFFNESS IN PATIENTS WITH CHRONIC HEART FAILURE

Abstract Aim Heart failure (HF) is associated to endothelial dysfunction, a pathological condition characterized by imbalance between the production of vasoconstrictor and vasodilator factors, increase in the production of cytokines, down-regulation of eNOS, platelets activation and increased oxidative stress. Furthermore, endothelial dysfunction promotes the increase of arterial stiffness, augmenting myocardial damage. Sacubitril/Valsartan (sac/val) is used in the treatment of HF reduced ejection fraction (HFrEF) and has been proven effective in reducing CV disease progression and all-cause mortality in HFrEF patients. The aim of the study was to evaluate the effect of sac/val on endothelial dysfunction and arterial stiffness in patients with HFrEF, at baseline and after 6 months of treatment. Moreover, we evaluated the effects of sac/val on oxidative stress levels and platelets activation. Materials Methods We enrolled 46 Caucasian patients (mean age 70.1±7.1), suffering from HFrEF. Inclusion criteria were LVEF&amp;lt;35, functional class NYHA II or III. All clinical evaluation and laboratory tests were performed at baseline and after 6 months of treatment. The serum values of the markers of oxidative stress (8-isoprostane, NOX-2) and platelets activation (Sp-selectin, GPVI) were assessed with ELISA sandwich. Endothelial function was estimated with the measurement of the reactive hyperemia index (RHI); arterial stiffness (AS) was evaluated with the measurement of carotid-femoral pulse wave velocity (PWV), augmentation pressure (AP) and augmentation index (AI). Results The mean dose of sac/val was 180.5±110 mg without serious adverse events. At 6 months, data showed a significant improvement in in hemodynamic and clinical parameters such as heart rate (HR) (p&amp;lt;0.0001), NT-ProBNP (p&amp;lt;0.0001), fasting plasma glucose (FPG) (p&amp;lt;0.0001). Furthermore, there was a significant reduction in oxidative stress, platelets activation and inflammatory indices. We observed a significant improvement in PWV (p&amp;lt;0.0001), AI (p&amp;lt;0.0001), AP (p&amp;lt;0.0001) and RHI (p&amp;lt;0.0001). A linear correlation analysis was performed to assess the association between vascular parameters and different covariates expressed as Δ variation between baseline and follow-up. ΔPWV was directly correlated with ΔHOMA (p=0.037), ΔIL-6 (p=0.034), ΔTNF-α (p=0.001), Δ8-isoprostane (p=0.016), ΔNox-2 (p=0.01), ΔGP6 (p=0.018), ΔSp-selectin (p=0.023); ΔRHI was inversely correlated with ΔHOMA (p=0.003), ΔIL-6 (p=0.004), ΔTNF-α (p=0.023), ΔCRP (p=0.011), Δ8-isoprostane (p=0.012), ΔNox-2 (p=0.01), ΔGP6 (p=0.014), ΔSp-selectin (p=0.015). From stepwise multivariate linear regression model, ΔTNF-α was the stronger predictor of ΔPWV, justifying 48.5% of its variation and ΔSp-selectin was the major predictor of ΔRHI explaining 23.2% of its variation. Conclusion The treatment with sac/val improved endothelial dysfunction and arterial stiffness, due to reduced levels of oxidative stress, platelet activation and inflammation.