Procoagulant effect of extracellular vesicles in patients after transcatheter aortic valve replacement or transcatheter aortic valve replacement with percutaneous coronary intervention.

Patients with severe aortic stenosis (AS) after replacement of the transcatheter aortic valve (TAVR) are more likely to develop thrombotic complications such as cerebral embolism and artificial valve thrombosis. However, the mechanism is not yet well defined. We aimed to explore the plasma extracellular vesicles (EVs) levels and their role in the induction of procoagulant activity (PCA) in patients receiving TAVR alone or TAVR with percutaneous coronary intervention (PCI). EVs were analyzed with flow cytometer. Markers of platelet and endothelial cell activation were quantified using selective enzyme-linked immunosorbent assay (ELISA) kits. Procoagulant activity (PCA) was assessed by clotting time, purified clotting complex assays, and fibrin production assays. Our results confirmed that EVs with positive phosphatedylserin (PS+EV), platelet EVs (PEVs) and positive tissue factor EVs (TF+EVs) were higher in patients following TAVR than before TAVR, particularly in TAVR with PCI. Furthermore, endothelial-derived EVs (EEVs) were also higher in patients after TAVR with PCI than pre-TAVR, however, the EEVs levels in TAVR alone patients were gradually reduce than pre-TAVR. In addition, we further proved that total EVs contributed to dramatically shortened coagulation time, increased intrinsic/extrinsic factor Xa and thrombin generation in patients after TAVR, especially in TAVR with PCI. The PCA was markedly attenuated by approximately 80% with lactucin. Our study reveals a previously unrecognized link between plasma EV levels and hypercoagulability in patients after TAVR, especially TAVR with PCI. Blockade of PS+EVs may improve the hypercoagulable state and prognosis of patients.

Inflammatory cytokines enhance procoagulant activity of platelets and endothelial cells through phosphatidylserine exposure in patients with essential hypertension.

The exact mechanism of the prothrombotic state of essential hypertension (EH) patients remains elusive. Our objective was to assess whether phosphatidylserine (PS) exposure on endothelial cells (ECs), platelets, and microparticles (MPs) can account for the hypercoagulability in EH patients. PS exposure on cells and MPs, mainly from platelets and ECs was analyzed with flow cytometry. Procoagulant activity (PCA) was evaluated by purified coagulation complex assays, clotting time, and fibrin turbidity. We found that EH patients exhibited elevated levels of PS+ platelets, serum-cultured ECs, MPs, endothelial-derived MPs and platelet-derived MPs compared to the controls (all P < 0.05). Moreover, platelets and MPs from the patients and their sera-cultured ECs showed markedly enhanced intrinsic/extrinsic FXa, thrombin, and fibrin generation, and greatly shortened coagulation time. This PCA could be blocked approximately 80%, by the addition of lactadherin. Furthermore, we detected elevated levels of IL-8, IL-6, and TNF-α in EH patients could activate platelets/ECs and induce elevated PS exposure on their membranes. Our results suggest that inflammatory cytokines could enhance procoagulant activity of platelets and endothelial cells via their PS exposure in EH patients. As such, a PS blockade may be a viable therapeutic strategy for treating such patients.

Phosphatidylserine-exposing blood and endothelial cells contribute to the hypercoagulable state in essential thrombocythemia patients.

The mechanisms of thrombogenicity in essential thrombocythemia (ET) are complex and not well defined. Our objective was to explore whether phosphatidylserine (PS) exposure on blood cells and endothelial cells (ECs) can account for the increased thrombosis and distinct thrombotic risks among mutational subtypes in ET. Using flow cytometry and confocal microscopy, we found that the levels of PS-exposing erythrocytes, platelets, leukocytes, and serum-cultured ECs were significantly higher in each ET group [JAK2, CALR, and triple-negative (TN) (all P < 0.001)] than those in controls. Among ET patients, those with JAK2 mutations showed higher levels of PS-positive erythrocytes, platelets, neutrophils, and serum-cultured ECs than TN patients or those with CALR mutations, which show similar levels. Coagulation function assays showed that higher levels of PS-positive blood cells and serum-cultured ECs led to markedly shortened coagulation time and dramatically increased levels of FXa, thrombin, and fibrin production. This procoagulant activity could be largely blocked by addition of lactadherin (approx. 70% inhibition). Confocal microscopy showed that the FVa/FXa complex and fibrin fibrils colocalized with PS on ET serum-cultured ECs. Additionally, we found a relationship between D-dimer, prothrombin fragment F1 + 2, and PS exposure. Our study reveals a previously unrecognized link between hypercoagulability and exposed PS on cells, which might also be associated with distinct thrombotic risks among mutational subtypes in ET. Thus, blocking PS-binding sites may represent a new therapeutic target for preventing thrombosis in ET.

Inflammatory cytokines induce neutrophil extracellular traps interaction with activated platelets and endothelial cells exacerbate coagulation in moderate and severe essential hypertension.

BACKGROUND: Essential hypertension (EH) patients suffer from paradoxically thrombotic rather than haemorrhagic, although the exact mechanism remains elusive. Our aim is to explore whether and how neutrophil extracellular traps (NETs) play the procoagulant role in EH patients, as well as evaluated whether the NET releasing were triggered by inflammatory cytokines. METHODS: The concentration of plasma NETs components were detected by ELISA. The morphology of cells and NETs formation were analysed using immunofluorescence. Procoagulant activity was analysed by clotting time, purified coagulation complex and fibrin generation assays. Phosphatidylserine (PS) exposure on endothelial cells (ECs) was analysed with flow cytometry. RESULTS: Moderate to severe EH patients plasma NETs levels were significantly higher compared to mild EH patients or controls. Furthermore, inflammatory cytokines can induce NETs generation, depleting these patients plasma inflammatory cytokines led to a reduction in NET releasing. NETs from moderate to severe EH patients neutrophils led to significantly decreased clotting time (CT), increased potency to generate thrombin and fibrin (all P  < 0.05). These procoagulant effects were markedly attenuated by approximately 70% using DNase I. Additionally, high concentrations NETs exerted a strong cytotoxic effect on ECs, conferring them a procoagulant phenotype. CONCLUSION: Our study reveals that EH drives a systemic inflammatory environment, which, in turn, drives neutrophils to prime and NET releasing, and found a link between hypercoagulability and NETs levels in moderate to severe EH patients. Therefore, anti-inflammatory combined with block the generation of NETs may represent a new therapeutic target for preventing thrombosis in EH patients.

Neutrophil extracellular traps exacerbate coagulation and endothelial damage in patients with essential hypertension and hyperhomocysteinemia.

Patients with essential hypertension (EH) and hyperhomocysteinemia (HHCY) suffer from more increased thrombotic events than those in EH alone. However, the underlying mechanisms for this effect are not well understood. This study hypothesized that neutrophil extracellular trap (NET) releasing may be triggered by HHCY in patients in EH, thereby predisposing them to a more hypercoagulable state. Using a modified-capture enzyme-linked immunosorbent assay (ELISA) method, we observed that cell-free DNA (CF-DNA) and myeloperoxidase DNA (MPO-DNA) in patients With EH and HHCY were significantly higher. The NET formation was also positively correlated with homocysteine levels, neutrophil-lymphocyte ratio (NLR), and hypercoagulable markers (thrombin-antithrombin complex, D-dimers). Furthermore, neutrophils from patients in EH with HHCY were found to be predisposed to amplified NET release when compared to patients in EH without HHCY or CTR. Coagulation function assays showed that NETs in patients With EH and HHCY resulted in a significantly increased ability to generate thrombin and fibrin than in those in EH without HHCY or CTR. These procoagulant effects of NETs in patients With EH and HHCY were markedly inhibited (approximately 70%) by the cleavage of NETs with DNase I. Isolated NETs from patients With EH and HHCY neutrophils also exerted a strong cytotoxic effect on endothelial cells (ECs), converted them to apoptosis. This study revealed a previously unrecognized association between the hypercoagulable state and neutrophils in patients With EH and HHCY. Therefore, blocking NETs may represent a new therapeutic objective for preventing thrombosis in these patients.

LINC00958 regulated miR-627-5p/YBX2 axis to facilitate cell proliferation and migration in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC), the subtype of head and neck cancers, is notorious for its high incidence and death rate. The role of long non-coding RNAs (lncRNAs) is discovered to be significant for the canceration and cancer progression. Long intergenic non-protein coding RNA 958 (LINC00958) is discovered as a carcinogene in multiple cancers, such as gastric cancer, pancreatic cancer, and glioma, but there has been no report about how LINC00958 functions in OSCC. The objective of our study is to unfold function and mechanism investigation on LINC00958 in OSCC. First, TCGA database showed the upregulation and prognostic significance of LINC00958 in head and neck squamous carcinoma. Then, we discovered in OSCC clinical samples that LINC00958 presented high expression and predicted poor prognosis. Also, LINC00958 was elevated in OSCC cells. In vitro gain- and loss-function experiments proved that LINC00958 facilitated cell growth, retarded apoptosis, accelerated migration, and epithelial-to-mesenchymal transition (EMT) in OSCC. Mechanistically, we confirmed the cytoplasmic expression of LINC00958 in OSCC cells, and revealed that LINC00958 sequestered miR-627-5p to upregulate YBX2 expression. Rescue assays indicated that LINC00958 regulated OSCC cell proliferation, motility and EMT through YBX2. Together, we showed that LINC00958 promoted OSCC progression through miR-627-5p/YBX2 axis, indicating LINC00958 as a new prognostic marker, and provided new perspectives for molecular targeted treatment for OSCC.

Over-activated PD-1/PD-L1 axis facilitates the chemoresistance of diffuse large B-cell lymphoma cells to the CHOP regimen.

Interaction between the programmed cell death ligand 1 (PD-L1) and programmed cell death 1 (PD-1) contributes to tumor cell resistance to chemotherapeutic agents. PD-L1 is expressed in the cells of diffuse large B-cell lymphoma (DLBCL), one common type of malignant non-Hodgkin lymphomas. However, little is known about how the PD-1/PD-L1 pathway functions in the pathogenesis of DLBCL. Therefore, the present study investigated whether and how the PD-1/PD-L1 axis is involved in regulating the sensitivity of CRL2631, a DLBCL cell line, to the CHOP (Cyclophosphamide, Hydroxydaunorubicin/adriamycin, Oncovin/vincristine and Prednisone) chemotherapeutic regimen. CHOP treatment significantly decreased cell survival rate and increased apoptosis in CRL2631 cells. The application of recombinant human PD-1 (rPD-1) significantly decreased the cytotoxic effects of the CHOP regimen in CRL2631 cells, but not in the CRL2631 cells with PD-L1 deficiency. In the CRL2631 cells, rPD-1 enhanced the activity of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt1) pathway. However, the activity level of the PI3K/Akt1 pathway was decreased in CHOP-treated CRL2631 cells. The selective PI3K inhibitor BKM120 significantly increased CHOP-induced apoptosis, but this effect was abolished by rPD-1 and aggravated by PD-L1 knockdown. In CHOP-treated PD-L1 knockdown cells, the increased apoptosis was markedly inhibited by the overexpression of constitutively active Akt1. Overall, the results demonstrate that the over-activated PD-1/PD-L1 axis is associated with chemotherapeutic resistance of DLBCL cells to the CHOP regimen, potentially through a PI3K-dependent mechanism.

Phosphatidylserine-exposing cells contribute to the hypercoagulable state in patients with multiple myeloma.

Multiple myeloma (MM) is characterized by an increased incidence of thromboembolic events, particularly when treated with immunomodulatory drugs (IMiDs) in combination with dexamethasone. The optimal prophylactic strategy to prevent the hypercoagulable state of patients with MM is still debated. The aim of the current study was to investigate the definitive role of phosphatidylserine (PS) in supporting procoagulant activity (PCA) in patients with MM. Patients with MM (n=20) and healthy subjects (n=15) were recruited for the present study. PS analyses were performed by flow cytometry and confocal microscopy. The PCA was evaluated by clotting time, purified coagulation complex assays and fibrin production assays. The percentage of PS+ blood cells was significantly higher in patients with MM than in healthy subjects. Additionally, the patient serum induced more PS exposure on endothelial cells (ECs) in vitro than serum from healthy subjects. Isolated blood cells from patients with MM and ECs cultured with patient serum in vitro demonstrated significantly shortened coagulation time, greatly intrinsic/extrinsic factor Xa generation and increased thrombin formation. In addition, the levels of PS+ erythrocytes, platelets, leukocytes, and ECs incubated with IMiDs and dexamethasone were higher than with IMiDs alone. The findings support the hypothesis that increased PS exposure on blood cells and ECs participates in the hypercoagulable state in patients with MM. Thus, blocking PS may be a novel therapeutic target for the prevention of thrombosis in these patients.

Phosphatidylserine-exposing blood cells and microparticles induce procoagulant activity in non-valvular atrial fibrillation.

BACKGROUND: The definitive role of phosphatidylserine (PS) in the prothrombotic state of non-valvular atrial fibrillation (NVAF) remains unclear. Our objectives were to study the PS exposure on blood cells and microparticles (MPs) in NVAF, and evaluate their procoagulant activity (PCA). METHODS: NVAF patients without (n = 60) and with left atrial thrombi (n = 18) and controls (n = 36) were included in our study. Exposed PS was analyzed with flow cytometry and confocal microscopy. PCA was evaluated using clotting time, factor Xa (FXa), thrombin and fibrin formation. RESULTS: PS+ blood cells and MPs were significantly higher in NVAF patients without and with left atrial thrombi (both P < 0.01) than in controls. Patients with left atrial thrombi showed increased PS+ platelets, neutrophils, erythrocytes and MPs compared with patients without thrombi (all P < 0.05). Moreover, in patients with left atrial thrombi, MPs primarily originated from platelets (56.1%) followed by leukocytes (21.9%, including MPs from neutrophils, monocytes and lymphocytes), erythrocytes (12.2%) and endothelial cells (8.9%). Additionally, PS+ blood cells and MPs contributed to markedly shortened coagulation time and dramatically increased FXa/thrombin/fibrin (all P < 0.001) generation in both NVAF groups. Furthermore, blockade of exposed PS on blood cells and MPs with lactadherin inhibited PCA by approximately 80%. Lastly, we found that the amount of PS+ platelets and MPs was positively correlated with thrombus diameter (all p < 0.005). CONCLUSIONS: Our results suggest that exposed PS on blood cells and MPs play a procoagulant role in NVAF patients. Blockade of PS prior to thrombus formation might be a novel therapeutic approach in these patients.

Increased blood cell phosphatidylserine exposure and circulating microparticles contribute to procoagulant activity after carotid artery stenting.

OBJECTIVE Phosphatidylserine (PS) is a major component of the inner leaflet of membrane bilayers. During cell activation or apoptosis, PS is externalized to the outer membrane, providing an important physiological signal necessary for the release of the microparticles (MPs) that are generated through the budding of cellular membranes. MPs express PS and membrane antigens that reflect their cellular origin. PS exposure on the cell surface and the release of MPs provide binding sites for factor Xa and prothrombinase complexes that promote thrombin formation. Relatively little is known about the role of PS exposure on blood cells and MPs in patients with internal carotid artery (ICA) stenosis who have undergone carotid artery stenting (CAS). The authors aimed to investigate the extent of PS exposure on blood cells and MPs and to define its role in procoagulant activity (PCA) in the 7 days following CAS. METHODS The study included patients with ICA stenosis who had undergone CAS (n = 70), matched patients who had undergone catheter angiography only (n = 30), and healthy controls (n = 30). Blood samples were collected from all patients just before the procedure after an overnight fast and at 2, 6, 24, 48, and 72 hours and 7 days after the CAS procedure. Blood was collected from healthy controls after an overnight fast. Phosphatidylserine-positive (PS+) MPs and blood cells were analyzed by flow cytometry, while PCA was assessed with clotting time analysis, purified coagulation complex assays, and fibrin formation assays. RESULTS The authors found that levels of PS+ blood cells and PS+ blood cell-derived MPs (platelets and platelet-derived MPs [PMPs], neutrophils and neutrophil-derived MPs [NMPs], monocytes and monocyte-derived MPs [MMPs], erythrocytes and erythrocyte-derived MPs [RMPs], and endothelial cells and endothelial cell-derived MPs [EMPs]) were increased in the 7 days following the CAS procedure. Specifically, elevation of PS exposure on platelets/PMPs, neutrophils/NMPs, and monocytes/MMPs was detected within 2 hours of CAS, whereas PS exposure was delayed on erythrocytes/RMPs and EMPs, with an increase detected 24 hours after CAS. In addition, PS+ platelets/PMPs peaked at 2 hours, while PS+ neutrophils/NMPs, monocytes/MMPs, and erythrocytes/RMPs peaked at 48 hours. After their peak, all persisted at levels above baseline for 7 days post-CAS. Moreover, the level of PS+ blood cells/MPs was correlated with shortened coagulation time and significantly increased intrinsic and extrinsic Xase, thrombin generation, and fibrin formation. Pretreatment of blood cells with lactadherin at their peak time point after CAS blocked PS, resulting in prolonged coagulation times, decreased procoagulant enzyme activation, and fibrin production. CONCLUSIONS The results of this study suggest that increased exposure of PS on blood cells and MPs may contribute to enhanced PCA in patients with ICA stenosis who have undergone CAS, explaining the risk of perioperative thromboembolic complications in these patients. PS on blood cells and MPs may serve as an important biomarker for predicting, and as a pivotal target for monitoring and treating, acute postoperative complications after CAS. ■ CLASSIFICATION OF EVIDENCE Type of question: association; study design: prospective cohort trial; evidence: Class I.

Enhanced Procoagulant Activity on Blood Cells after Acute Ischemic Stroke.

The role of phosphatidylserine (PS)-mediated procoagulant activity (PCA) in stroke remains unclear. To ascertain this role, early dynamic evolution of PS exposure on blood cells and released microparticles (MPs) and the corresponding PCA were evaluated in patients with acute ischemic stroke (AIS). Flow cytometry analyses revealed that initial levels of PS exposure on erythrocyte, platelet, and leukocyte were 2.40-, 1.36-, and 1.38-fold higher, respectively, in AIS than the risk factor-matched (RF) controls. Concomitantly, total PS+ MPs were increased in AIS (1949 ± 483/µl) compared with the RF group (1674 ± 387/µl; P = 0.019) and healthy controls (1052 ± 179/µl; P < 0.001). Specifically, PS+ erythrocytes gradually increased within 1 week. PS+ platelets and MPs peaked at 24 h and declined at 7 days, while PS+ leukocytes were markedly elevated at 24 h. Further, PS exposure on blood cells and MPs in stroke resulted in shortened clotting time with an accompanying increase in FXa and thrombin formation significantly. Treatment with lactadherin, a PS antagonist, delayed the coagulation time by approximately 20 % and blocked the generation of FXa and thrombin by about 50 %. Furthermore, initial counts of PS+ platelets and platelet MPs significantly correlated with stroke severity. Thrombin generation promoted by platelets and MPs at 12 h was significantly higher in patients with cardioembolism than in patients without. The thrombophilic susceptibility of AIS patients can be partly ascribed to PS exposure on blood cells and the release of MPs. Our studies identify PS exposure as a potentially novel therapeutic target in the treatment of AIS.

Oroxylin A attenuates cigarette smoke-induced lung inflammation by activating Nrf2.

Oroxylin A, a natural flavonoid isolated from the medicinal herb Scutellaria baicalensis Georgi, has been reported to have anti-inflammatory and antioxidant properties. However, the effect of oroxylin A on cigarette smoke (CS)-induced lung inflammation remains unclear. In this study, the ability of oroxylin A to protect against CS-induced lung inflammation was detected in vivo and in vitro. Oroxylin A was administered intraperitoneally to mice 2h prior CS exposure every day for five consecutive days. BEAS-2B bronchial epithelial cells and RAW264.7 cells were used to investigate the molecular mechanism of oroxylin A in vitro. In vivo, the results showed that oroxylin A dose-dependently attenuated CS-induced lung histopathologic changes, expression of cytokines TNF-α, IL-1ß, and MCP-1, and levels of oxidative biomarkers 3-nitrotyrosine and 8-isoprostane. Meanwhile, oroxylin A up-regulated GSH level and glutathione reductase (GR) activity in lung tissues. In vitro, oroxylin A significantly up-regulated Nrf2 expression and total cellular glutathione level in cigarette smoke extract (CSE)-stimulated cells. In addition, oroxylin A promoted Nrf2 binding to antioxidant response element (ARE) and up-regulated ARE-regulated gene such as heme oxygenase-1 (HO-1), GPx, and GR in CSE-stimulated cells. Oroxylin A could protect both epithelial cells and macrophages from damage by cigarette smoke in vitro. Taken together, these data indicated that oroxylin A attenuated oxidative stress and lung inflammation induced by CS via activating Nrf2 signaling pathway. Oroxylin A may be a protective agent against CS-induced lung inflammation and chronic obstructive pulmonary disease.

Microparticles and blood cells induce procoagulant activity via phosphatidylserine exposure in NSTEMI patients following stent implantation.

BACKGROUND: Relatively little is known about the role of phosphatidylserine (PS) in procoagulant activity (PCA) in patients with non-ST-elevated myocardial infarction (NSTEMI) after stent implantation. This study was designed to evaluate whether exposed PS on microparticles (MPs) and blood cells were involved in the hypercoagulable state in NSTEMI patients with stent implantation. METHODS: NSTEMI patients (n=90) and healthy controls (n=20) were included in our study. PS exposure on MPs and blood cells was analyzed with flow cytometer and confocal microscope. PCA was evaluated by clotting time, purified coagulation complex assays and fibrin production assays. RESULTS: Baseline levels of MPs and PS+ blood cells were significantly higher (P<0.001) in the patients than in controls. After stent implantation, a remarkable increase was observed in both MPs and PS+ blood cells. Specifically, PS+ MPs, PS+ platelets and erythrocytes peaked at 18h following stent implantation, while PS+ leukocytes peaked on day 2. In addition, circulating MPs (mostly derived from platelets, leukocytes, erythrocytes and endothelial cells) cooperating with PS+ blood cells, contributed to markedly shortened coagulation time and markedly increased FXa/thrombin/fibrin (all P<0.01) generation in patient group. Moreover, blockade of exposed PS on MPs and cells with lactadherin inhibited PCA by approximately 70%. CONCLUSIONS: Our results suggest that PS+ MPs and blood cells play a procoagulant role in NSTEMI patients following stent implantation. Blockade of PS could become a novel therapeutic modality for the prevention of thrombosis in these patients.

[Clinical study of heparin-induced thrombocytopenia].

OBJECTIVE: To observe the incidence of heparin-induced thrombocytopenia (HIT) in patients received unfractionated heparin (UFH) treatment, and explore the feasibility of monitoring HIT by platelet counts, as well as the significance of HIT-antibody test in HIT diagnosis. METHODS: 145 patients received UFH treatment in Vascular Surgery Department were studied. Before and after the UFH treatment, platelet counts, HIT-antibody ELISA test and heparin-induced platelet aggregation (HIPA) were tested. RESULTS: Among the 145 patients, thrombocytopenia occurred in 40 (27.6%) cases, HIT-antibody ELISA test positive in 59 (40.7%) cases, HIPA test positive in 26 (17.9%) cases. The HIT was diagnosed in 24 (16.5%) cases, and heparin-induced thrombocytopenia and thrombosis (HITTS) occurred in 5 (3.4% in all cases, and 20.8% in HIT patients). In HIT patients, 15 patients (62.5%) were thrombocytopenia, HIT-antibody positive and HIPA test positive. Platelet counts in all of the 24 patients recovered to normal or level before UFH treatment in 3-6 days after heparin withdrawal therapy. CONCLUSION: HIT can be early diagnosed by monitoring platelet counts, HIT-antibody ELISA test and HIPA test. Withdrawal of heparin therapy in time and use of alternative anticoagulant, HITTS rate might be expected to decline further.