Article

Assessment of the Procoagulant Activity of Microparticles and the Protein Z System in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery

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Abstract

To understand the coagulation changes after off-pump coronary artery bypass (OPCAB) surgery, we evaluated the procoagulant activity of microparticles (MPs) and microparticles exposing tissue factor (MPs-TF), together with the levels of total tissue factor (TF), protein Z (PZ), protein Z-dependent protease inhibitor (ZPI), and factor X (FX) before (first day) and 1 week after surgery (seventh day) in plasma samples from 30 patients. Twenty healthy controls were also included. Compared to the controls, patients scheduled for surgery had significantly higher MPs-TF procoagulant activity and lower TF levels ( P = .0006, P = .02, respectively). In the whole cohort, median procoagulant activity of MPs-TF and median levels of TF and ZPI were significantly lower ( P = .02, P = .0003, and P = .004, respectively), while median levels of PZ and FX were significantly higher ( P = .02 and P = .002, respectively) on the seventh day compared to the first day. Our results suggest that OPCAB surgery has a significant effect on the procoagulant activity of MPs-TF and the PZ system.

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... The purpose of the pilot analysis presented here was to evaluate the presence or absence of anti-PZ antibodies in patients undergoing off-pump coronary artery bypass (OPCAB) surgery. We have previously observed the significant effect of OPCAB surgery on PZ and ZPI levels [7]. Thus, in this initial report we have focused on the evaluation of the next component of the PZ system, anti-PZ antibodies. ...
... Thus, in this initial report we have focused on the evaluation of the next component of the PZ system, anti-PZ antibodies. This study extends our previous research on the PZ system in OPCAB individuals [7]. ...
... In the current study, we used the same cohort of patients that were reported on previously [7]. The participants' enrolment, data collection, and the definitions of the clinical variables have been described in detail [7]. ...
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Background: Considerable attention has been focused over the past several years on the protein Z (PZ) system. However, little is known about the role of auto-antibodies to PZ (anti-PZ) in cardiac surgery patients. Aim: In the present pilot study, we investigated plasma levels of anti-PZ in patients undergoing off-pump coronary artery bypass (OPCAB) surgery. Material and methods: Thirty patients with coronary artery disease scheduled for OPCAB surgery were enrolled in this study. Plasma levelsof anti-PZ IgM and anti-PZ IgG were measured before surgery and one week after surgery using enzyme-linked immunosorbent assay. Results: None of the subjects were shown to have positive results for anti-PZ IgM and anti-PZ IgG either before and one week after OPCAB surgery. Conclusions: These results suggest that anti-PZ autoantibodies are not an effective component of the PZ system in OPCAB patients.
... Po zapoznaniu się z pracą Andriamandimbisoa i wsp., przychodzi na myśl kilka uwag, które autorzy mogą wziąć pod uwagę w kolejnych badaniach. Po pierwsze, biorąc pod uwagę fakt, że pacjenci z aCL są bardziej narażeni na rozwój powikłań zakrzepowych, cenną obserwacją byłaby ocena wszystkich składników układu białka Z: PZ, ZPI, FX i przeciwciał anty-PZ [6]. Chociaż przeciwciała anty-PZ są rzadko obserwowane we krwi pacjentów ze zdiagnozowanymi chorobami sercowo-naczyniowymi [5,7], taka analiza mogłaby odpowiedzieć na pytanie, czy ten PZ is a cofactor of ZPI, which in fact, increases its anticoagulant properties a thousand fold [3]. ...
... Little is known about the mechanisms controlling blood PZ con- First of all, given the fact that patients with aCL are at greater risk of developing thrombosis, a valuable observation would be the assessment of all components of the protein Z system: PZ, ZPI, FX, and anti-PZ antibodies [6]. Although anti-PZ antibodies are rarely found in cardiovascular diseases [5,7], such an analysis could answer the question of whether anti-PZ antibodies active- ...
... Over the past few decades, the mechanisms of acute vascular events of smokers have been well studied, including induction of a hypercoagulable state, increased myocardial work, carbon monoxide-mediated reduction in the oxygen-carrying capacity of the blood, induction of endothelial dysfunction, coronary vasoconstriction, and catecholamine release. [4,16] In the present study, no positive association between smoking and POAF was observed, and smoking may have a protective effect on POAF. With a growing number of related studies, this phenomenon may be explained by that smokers have higher baseline levels of sympathetic activity and higher adrenergic tolerance. ...
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... Of note, other conditions may also affect EV characteristics and function. For instance, off-pump coronary artery bypass (OPCAB) surgery displays a significant effect on the procoagulant activity of MP as well as on tissue factor and protein Z system [44]. ...
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... According to the recent reports, in 2015, about 17.9 million individuals died from CVD, and 7.3 million of mentioned deaths occur because of CAD [140]. Diverse molecules on the microparticles surface induce procoagulant features leading to acute coronary events [141]. Notably, melatonin has anticoagulant properties as reported by Petra and co-workers. ...
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... CHD, one of the leading causes of death in the world, is a complex metabolic disorder due to genetic and environmental interactions. [21][22][23] Metabolomics, a powerful technical system that studies the entire metabolic pathway of a particular biological system. This technology has been increasingly used to identify metabolic biomarkers and improve clinical diagnosis and treatment of diseases. ...
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... A valuable observation made by the authors is the finding of a lower concentration of PZ in patients diagnosed with arterial hypertension. Nevertheless, this requires confirmation in subsequent studies due to the fact that other research has showed no difference in PZ concentration depending on the absence or presence of arterial hypertension in patients with coronary artery disease [4]. ...
... [3] AMI is typically caused by activation of platelet aggregation at the site of a ruptured or eroded atherosclerotic plaque. [4,5] It is well recognized that age, sex, dyslipidemia, atherosclerosis, hypertension, smoking and diabetes are significantly associated with the risk of AMI. [6][7][8] Although the relationship between risk factors and AMI has been extensively researched, however, the relation between these 2 remains controversial due to somewhat divergent of the results depending on different clinical subgroups of AMI. ...
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... One of the most widely used analytical methods for quantifying MVs levels and markers is flow cytometry (279). There are many different analytical methods used in MVs studies, such as electron microscopy (280), nanoparticle tracking analysis (280), western blot (280), dynamic light scattering (281), and enzyme-linked immunosorbent assay (282), however none of them is currently used in routine diagnostics. The vast majority of methods require special preparation of biological material samples and specialized equipment (283). ...
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Background and purposeStroke is an important cause of death and disability throughout the world. Microparticles play a cardinal role in vascular hemostasis. The primary aim of this study was to evaluate the procoagulant activity of microparticles and levels of tissue-factor-bearing microparticles (MPs-TF), tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with acute ischaemic stroke.Methods Seventy-three patients with a diagnosis of acute ischaemic stroke were included. Venous blood samples were drawn on the first day and the seventh day after stroke onset. Plasma microparticles, MPs-TF, TF and TFPI were determined by enzyme-linked immunosorbent assay. Assessment variables were timing of blood collection, type of stroke treatment, presence or absence of diabetes mellitus and hypertension, and scores on the National Institutes of Health Stroke Scale together with scores on the modified Rankin Scale.ResultsWhilst MPs-TF and TFPI levels of stroke subjects were significantly higher (median, 1.63 vs. 0.73 pg/ml; median, 114.26 vs. 78.60 ng/ml, respectively), TF levels in the plasma of stroke patients were significantly lower (median, 82.27 vs. 97.80 pg/ml) than those of healthy individuals. Lower levels of TF were detected in patients with severe stroke in comparison with patients with mild stroke. Moreover, the data also showed that in stroke patients not treated with alteplase the activity of microparticles was significantly higher 1 week after diagnosis in comparison with the activity at the time of diagnosis.Conclusion Our findings suggest that patients with acute ischaemic stroke have increased generation of MPs-TF. Nevertheless, further studies are needed in order to confirm such inference.
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Objective Growth differentiation factor-15 (GDF-15) has been identified as a strong marker of cardiovascular disease; however, no data are available concerning the role of GDF-15 in the occurrence of organ dysfunction during coronary artery bypass grafting (CABG) associated with cardiopulmonary bypass (CPB). Methods Five arterial blood samples were taken sequentially in 34 patients from anesthesia induction (IND) until 24 h after arrival at the intensive care unit (ICU). Plasma levels of GDF-15, follistatin-like 1 (FLST1), myeloperoxidases (MPO), hydroperoxides and plasma antioxidant status (PAS) were measured at each time-point. Markers of cardiac (cardiac-troponin I, cTnI) and renal dysfunction (neutrophil gelatinase-associated lipocalin, NGAL) and other classical biological factors and clinical data were measured. Results Plasma GDF-15 levels increased gradually during and after surgery, reaching nearly three times the IND levels in the ICU (3,075±284 ng/L vs. 1,061±90 ng/L, p<0.001). Plasma MPO levels increased dramatically during surgery, attaining their highest level after unclamping (UNCLAMP) (49±11 ng/mL vs. 1,679±153 ng/mL, p<0.001) while PAS significantly decreased between IND and UNCLAMP (p<0.05), confirming the high oxidative status induced by this surgical procedure. ICU levels of GDF-15 correlated positively with cTnI and NGAL (p = 0.006 and p = 0.036, respectively), and also with hemoglobin and estimated glomerular filtration rate (eGFR). Among all the post-operative biomarkers available, only eGFR, NGAL and GDF-15 measured at ICU arrival were significantly associated with the onset of acute kidney injury (AKI). Patients with a EuroSCORE >3 were shown to have higher GDF-15 levels. Conclusions During cardiac surgery associated with CPB, GDF-15 levels increased substantially and were associated with markers of cardiac injury and renal dysfunction.
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Background Recent studies indicated that microRNAs (miRNAs, miRs) were important for many biological and pathological processes, and they might be potential biomarkers for cardiovascular diseases. The present study aims to determine the release patterns of miRNAs in cardiac surgery and to analyze the ability of miRs to provide early prediction of perioperative myocardial infarction (PMI) in patients undergoing coronary artery bypass graft (CABG) surgery. Methodology/Principal Findings Thirty on-pump CABG patients were recruited in this study; and miR-499, miR-133a and miR-133b, cardiac troponin I (cTnI) were selected for measurement. Serial plasma samples were collected at seven perioperative time points (preoperatively, and 1, 3, 6, 12, 24, and 48 hours after declamping) and were tested for cTnI and miRs levels. Importantly, miR levels peaked as early as 1–3 hours, whereas cTnI levels peaked at 6 hours after declamping. Peak plasma concentrations of miRs correlated significantly with cTnI (miR-499, r = 0.583, P = 0.001; miR-133a, r = 0.514, P = 0.006; miR-133b, r = 0.437, P = 0.05), indicating the degree of myocardial damage. In addition, 30 off-pump CABG patients were recruited; miR-499 and miR-133a levels were tested, which were significantly lower in off-pump group than in on-pump group. A prospective cohort of CABG patients (n = 120) was recruited to study the predictive power of miRs for PMI. The diagnosis of PMI strictly adhered to the principles of universal definition of myocardial infarction. The data analysis revealed that miR-499 had higher sensitivity and specificity than cTnI, and indicated that miR-499 could be an independent risk factor for PMI. Conclusion Our results demonstrate that circulating miR-499 is a novel, early biomarker for identifying perioperative myocardial infarction in cardiac surgery.
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Tissue factor (TF) contributes to thrombosis following plaque disruption in acute coronary syndromes (ACS). Aim of the study was to investigate the impact of plasma TF activity on prognosis in patients with ACS. One-hundred seventy-four patients with unstable Angina pectoris (uAP) and 112 patients with acute myocardial infarction (AMI) were included with a mean follow up time of 3.26 years. On admission, plasma TF activity was assessed. Patients were categorized into 2 groups: a high-TF activity group with TF >24 pmol/L and low TF activity group with TF ≤ 24 pmol/L. Fifteen cardiovascular deaths occurred in the uAP group and 16 in the AMI group. In AMI TF activity was 24,9 ± 2,78 pmol/l (mean ± SEM) in survivors and 40,9 ± 7,96 pmol/l in nonsurvivors (P = 0.024). In uAP no differences were observed (25.0 ± 8.04 pmol/L nonsurvivors vs. 25.7 ± 2.14 pmol/L survivors; P = 0.586). Kaplan-Meier estimates of survival at 3.26 years regarding TF activity in AMI were 81.3% and 92.2% with an hazard ratio of 3.02 (95% CI [1.05-8.79], P = 0.03). The Cox proportional hazards model adjusting for correlates of age and risk factors showed that plasma TF activity was an independent correlate of survival (hazard ratio 9.27, 95% CI [1.24-69.12], P = 0.03). In an additional group of patients with uAP and AMI, we identified circulating microparticles as the prevailing reservoir of plasma TF activity in acute coronary syndromes. Systemic TF activity in AMI has an unfavorable prognostic value and as a marker for dysregulated coagulation may add to predict the atherothrombotic risk.
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Statins reduce cardiovascular disease risk and affect endothelial function by cholesterol-dependent and independent mechanisms. Recently, circulating (detached) endothelial cells and endothelial microparticles (EMP) have been associated with endothelial functioning in vitro and in vivo. We investigated whether simvastatin affects endothelial detachment and release of EMP. Human umbilical vein endothelial cells (HUVECs) were incubated with clinically relevant concentrations of simvastatin (1.0 and 5.0 microM), with or without mevalonic acid (100 microM) or geranylgeranylpyrophosphate (GGPP; 20 microM) for 24 hours, and analyzed by flowcytometry and Western blot. Simvastatin at 1.0 and 5.0 microM increased cell detachment from 12.5+/-4.1% to 26.0+/-7.6% (p=0.013) and 28.9 +/- 2.2% (p=0.002) as well as EMP release (p=0.098 and p=0.041, respectively). The majority of detached cells was apoptotic, although the fraction of detached cells that showed signs of apoptosis (>70%) was unaffected by simvastatin. Detached cells and EMP contained caspase 3 and caspase 8, but not caspase 9. Restoring either cholesterol biosynthesis and prenylation (mevalonate) or prenylation alone (GGPP) reversed all simvastatin-induced effects on cell detachment and EMP release. Adherent cells showed no signs of simvastatin-induced apoptosis. Simvastatin promotes detachment and EMP release by inhibiting prenylation, presumably via a caspase 8-dependent mechanism. We hypothesize that by facilitating detachment and EMP release, statins improve the overall condition of the remaining vascular endothelium.
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Tissue factor (TF) is an integral membrane protein essential for hemostasis. During the past several years, a number of studies have suggested that physiologically active TF circulates in blood at concentrations greater than 30 pM either as a component of blood cells and microparticles or as a soluble plasma protein. In our studies using contact pathway-inhibited blood or plasma containing activated platelets, typically no clot is observed for 20 minutes in the absence of exogenous TF. An inhibitory anti-TF antibody also has no effect on the clotting time in the absence of exogenous TF. The addition of TF to whole blood at a concentration as low as 16 to 20 fM results in pronounced acceleration of clot formation. The presence of potential platelet TF activity was evaluated using ionophore-treated platelets and employing functional and immunoassays. No detectable TF activity or antigen was observed on quiescent or ionophore-stimulated platelets. Similarly, no TF antigen was detected on mononuclear cells in nonstimulated whole blood, whereas in lipopolysaccharide (LPS)-stimulated blood a significant fraction of monocytes express TF. Our data indicate that the concentration of physiologically active TF in non-cytokine-stimulated blood from healthy individuals cannot exceed and is probably lower than 20 fM.
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Cardiovascular diseases (CVDs) are a common cause of death, and a search for biomarkers for risk stratification is warranted. Elevated levels of cell-derived microparticles (MPs) are found in patients with CVD and in groups with risk factors for CVD. Subpopulations of MPs are promising biomarkers for improving risk prediction, as well as monitoring treatment. However, the field has been hampered by technical difficulties, and the ongoing development of sensitive standardized techniques is crucial for implementing MP analyses in the clinic. Large prospective studies are required to establish which MPs are of prognostic value in different patient groups. In this review, we discuss methodological challenges and progress in the field, as well as MP populations that are of interest for further clinical evaluation.
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Reports in the last decade have suggested that the role of platelets in atherosclerosis and its thrombotic complications may be mediated, in part, by local secretion of platelet-derived microvesicles (pMVs), small cell blebs released during the platelet activation process. MVs are the most abundant cell-derived microvesicle subtype in the circulation. High concentrations of circulating MVs have been reported in patients with atherosclerosis, acute vascular syndromes, and/or diabetes mellitus, suggesting a potential correlation between the quantity of microvesicles and the clinical severity of the atherosclerotic disease. pMVs are considered to be biomarkers of disease but new information indicates that pMVs are also involved in signaling functions. pMVs evoke or promote haemostatic and inflammatory responses, neovascularization, cell survival, and apoptosis, processes involved in the pathophysiology of cardiovascular disease. This review is focused on the complex cross-talk between platelet-derived microvesicles, inflammatory cells and vascular elements and their relevance in the development of the atherosclerotic disease and its clinical outcomes, providing an updated state-of-the art of pMV involvement in atherothrombosis and pMV potential use as therapeutic agent influencing cardiovascular biomedicine in the future.
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Due to its receptor activity for factor VII, tissue factor (TF) is primary initiator of the blood coagulation cascade and ensures rapid hemostasis in case of organ damage. Inflammatory cytokines, such as tumor necrosis factor-α or interleukins, strongly induce expression of both full-length TF as well as the alternatively spliced TF in endothelial and blood cells. Beyond its role in hemostasis, TF also has signaling activity and promotes pleiotropic inflammatory responses via protease-activated receptors in concert with other coagulation factors. Alteration of TF expression and TF alternative splicing provides an effective means to change the endothelial phenotype and modulate inflammatory responses of the vessel.
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Thrombosis is a leading cause of morbidity and mortality. Detection of a prothrombotic state using biomarkers would be of great benefit to identify patients at risk of thrombosis that would benefit from thromboprophylaxis. The addition of biomarkers to these scores could improve risk assessment accuracy. Tissue factor (TF) is a highly procoagulant protein that under normal conditions is not present in the blood. However, increased levels of TF in the blood in the form of microparticles (MPs) (also called extracellular vesicles) are observed under various pathological conditions. In this review, we will discuss studies that have measured MP-TF activity using two similar FXa generation assays in a variety of diseases. One of the most robust signals for MP-TF activity (16–26 fold higher than healthy controls) is observed in pancreatic cancer patients with venous thromboembolism. In this case, the TF + MPs appear to be derived from the cancer cells. Surprisingly, cirrhosis and acute liver injury are associated with 17-fold and 38-fold increases in MP-TF activity, respectively. Based on mouse models, we speculate that the TF + MPs are derived from hepatocytes. More modest increases are observed in patients with urinary tract infections (6-fold) and in a human endotoxemia model (9-fold) where monocytes are the likely source of the TF + MPs. Finally, there is no increase in MP-TF activity in the majority of cardiovascular disease patients. These studies indicate that MP-TF activity may be a useful biomarker to identify patients with particular diseases that have an increased risk of thrombosis.
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Introduction: Protein Z (PZ)-dependent protease inhibitor (ZPI) is a serine protease inhibitor that efficiently inhibits activated factor X when ZPI is in complex with PZ. We previously reported significantly higher concentrations of plasma ZPI (and PZ) in women during normal pregnancy than in non-pregnant women. Methods: We explored the possible contribution of estrogen to the ZPI levels in patients with or without bilateral oophorectomy (OVX), which induces artificial menopause where blood estrogen levels drastically decrease. One hundred ninety-one pre-menopausal Japanese women who underwent open hysterectomy owing to neoplasms participated in this study and were divided into two groups: 98 OVX and 93 Non-OVX cases. Plasma ZPI was measured by ELISA. Results and conclusion: Contrary to our working hypothesis, plasma ZPI levels increased significantly in the OVX group after surgery when compared with the pre-operation levels. When these patients were individually analyzed, their ZPI value also rose significantly from pre-operation to post-operation levels. In contrast, plasma PZ levels remained unchanged. The significantly increased ZPI and unchanged PZ levels were also observed in the Non-OVX group. The increased ZPI levels were not significantly related to 17β-estradiol, luteinizing hormone or follicular stimulating hormone levels, clearly indicating that estrogen did not contribute to the plasma ZPI concentrations. Typical acute phase reactants fibrinogen and C-reactive protein (CRP) were also significantly elevated after surgery in both OVX and Non-OVX groups. However, only weakly significant linear relationships were observed between ZPI and fibrinogen or CRP, indicating the presence of alternative regulatory mechanisms underlying their plasma concentrations.
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Microparticles (MP) are small extracellular vesicles (30-1,000 nm) that are released from activated cells or platelets. Exposure of negatively charged phospholipids and tissue factor (TF) renders MP procoagulant. Normal plasma levels of intravascular TF-exposing MP (TFMP) are low, but their number may rise in pathological conditions, including cancer and infectious disease. Emerging evidence indicates an important role for these circulating TFMP in the pathogenesis of thrombotic complications such as venous thromboembolism and disseminated intravascular coagulation, whereas their contribution to arterial thrombosis is less studied. Despite serious limitations of the currently available assays for measuring TFMP levels or the procoagulant activity associated with TFMP with respect to sensitivity and specificity, the scientific interest in TFMP is rapidly growing because their application as prognostic biomarkers for thrombotic complications is promising. Future advances in detection methods will likely provide more insight into TFMP and eventually improve their clinical utility. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
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Background: The optimal scheme of thromboprophylaxis in bariatric surgery remains uncertain, because clinical practice is different between countries and randomized trials are lacking. Objectives: The primary objective of this randomized multicenter study was to determine the optimal regimen of enoxaparin providing an antifactor Xa peak activity between .3 and .5 IU/mL at equilibrium and to evaluate the course of procoagulant microparticles (MPs). Setting: University hospital. Methods: A total of 164 patients scheduled for gastric bypass were allocated to 3 groups (A, B, and C) of enoxaparin treatment (4000, 6000, or 2×4000 IU, respectively). Antifactor Xa activity was measured before and 4 hours after each injection from D0 to D2. Doppler screening of the lower limbs was performed at D1, D9, and D30. Bleeding (BE) and thrombotic events (TE) were recorded during the first postoperative month. Total MPs were measured at D0, D9, and D30. MPs of leucocyte, platelet, and granulocyte origin were assessed in one third of the patients from each group. The 3 groups were compared by ANOVA. Results: A total of 135 patients were analyzed. The equilibrium of antifactor Xa peak levels was obtained 52 hours after the presurgery injection and 12.8%, 56.4%, and 27.3% of the patients reached the target in groups A, B, and C, respectively (P<.001). No TE was detected. BE occurred in 1, 2, and 6 patients in groups A, B, and C, respectively). Total MPs remained unchanged over time. While no significant variation was observed in the other groups, platelet GP1 b(+)-MPs increased (P = .01) at D9 in group C, suggesting an incomplete control of anticoagulation leading to cell activation and procoagulant MP release that was confirmed by the higher MP levels measured at D30 (P = .04). CD66(+)-MPs were also highly elevated at J9 and D30 in group C indicating a granulocyte contribution. Conclusions: This study shows that a single dose of enoxaparin 6000 IU/d allowed most of the patients to reach the target range of antifactor Xa activity without increasing the bleeding risk, with the most likely efficient reduction of procoagulant MPs. (Surg Obes Relat Dis 2015;0:000-000.) © 2015 American Society for Metabolic and Bariatric Surgery. All rights reserved.
Article
Coronary artery bypass grafting (CABG) is the gold-standard treatment for coronary artery disease, but the long-term benefits of robotic CABG remain unclear. Between January 2007 and November 2014, 240 consecutive patients (187 male and 53 female, average age 59 years) underwent robotic off-pump CABG with the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA) in our center. Totally endoscopic coronary artery bypass (TECAB) (n = 100) or mini-thoracotomy coronary artery bypass (MINICAB) (n = 140) grafting was performed with skeletonized internal mammary arteries (IMA). Patients were followed up and graft patency was assessed every 6 months by coronary angiography or 64-multi-slide computed tomographic angiography. All cases were completed without conversion to median sternotomy or cardiopulmonary bypass. A total of 237 single IMA grafts (98.3%) and 4 bilateral IMA grafts (1.7%) were used. No operative mortality was observed. Hybrid revascularization of non-left anterior descending vessels was performed in 24 patients (10%). No death, stroke, or myocardial infarction occurred in the follow-up of 41.1 ± 12.9 months. All grafts were patent before discharge. The IMA graft patency was 97.1% in TECAB and 96.4 % in MINICAB over 3 years (up to 91 months) postoperatively. Robotic off-pump CABG using IMA grafts is a safe and effective procedure in selected patients. The long-term outcome and patency of IMA grafts are excellent. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
Article
Conclusive evidence is lacking regarding the benefits and risks of performing off-pump versus on-pump coronary artery bypass graft (CABG) for patients with diabetes. This study aims to compare clinical outcomes after off-pump and on-pump procedures for patients with diabetes. The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial enrolled patients with type 2 diabetes and documented coronary artery disease, 615 of whom underwent CABG during the trial. The procedural complications, 30-day outcomes, long-term clinical and functional outcomes were compared between the off-pump and on-pump groups overall and within a subset of patients matched on propensity score. On-pump CABG was performed in 444 (72%) patients, and off-pump CABG in 171 (28%). The unadjusted 30-day rate of death/myocardial infarction (MI)/stroke was significantly higher after off-pump CABG (7.0 vs 2.9%, P = 0.02) despite fewer complications (10.3 vs 20.7%, P = 0.003). The long-term risk of death [adjusted hazard ratio (aHR): 1.41, P = 0.2197] and major cardiovascular events (death, MI or stroke) (aHR: 1.47, P = 0.1061) did not differ statistically between the off-pump and on-pump patients. Within the propensity-matched sample (153 pairs), patients who underwent off-pump CABG had a higher risk of the composite outcome of death, MI or stroke (aHR: 1.83, P = 0.046); the rates of procedural complications and death did not differ significantly, and there were no significant differences in the functional outcomes. Patients with diabetes had greater risk of major cardiovascular events long-term after off-pump CABG than after on-pump CABG. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
Article
The pathological consequences of decreased protein Z (PZ) and/or Z-dependent protease inhibitor (ZPI) levels remain as yet unclear, despite a growing body of evidence which supports their involvement in an increased thrombotic risk. The purpose of the present study was 2-fold: to evaluate plasma concentrations of protein Z and ZPI in patients with essential thrombocythemia (ET) and to determine their significance in thrombotic complications. The median (range) plasma concentrations of PZ in our patients with ET were lower, but not significantly, than in healthy individuals: PZ (1.42 µg/mL, 0.36-3.14 µg/mL vs 1.6 µg/mL, 0.75-2.56 µg/mL, P = .08). On the other hand, the median (range) plasma concentrations of ZPI in the said patients with ET were meaningfully lower than in the reference group: ZPI (3.22 µg/mL, 0.85-6.97 µg/mL vs 4.41 µg/mL, 1.63-7.83 µg/mL, P = .0004). More importantly, the study revealed a statistically significant lower concentration of PZ and ZPI in patients with the presence of the JAK2V617F mutation relative to patients without the mutation, for PZ: 1.38 µg/mL, 0.36-2.6 µg/mL versus 1.63 µg/mL, 0.88-3.14 µg/mL, P = .03, and ZPI 2.89 µg/mL, 0.85-5.91 µg/mL versus 3.61 µg/mL, 1.53-6.97 µg/mL, P = .002. Additionally, significant differences between the concentrations of PZ and ZPI were found in patients with venous thrombotic episodes compared to healthy individuals, for PZ: 1.23 µg/mL, 0.82-1.99 µg/mL versus 1.6 µg/mL, 0.75-2.56 µg/mL, P = .043, and ZPI: 2.42 µg/mL, 0.85-4.21 µg/mL versus 4.41 µg/mL, 1.63-7.83 µg/mL, P < .0001. To recapitulate, our results suggest that the deficiency of PZ may increase tendency to thrombosis in patients with ET. © The Author(s) 2015.
Article
Background Equations to estimate glomerular filtration rate (GFR) are routinely used to assess kidney function. Current equations have limited precision and systematically underestimate measured GFR at higher levels.
Article
Unlabelled: Tissue factor (TF) is expressed in the heart where it is required for haemostasis. High levels of TF are also expressed in atherosclerotic plaques and likely contribute to atherothrombosis after plaque rupture. Indeed, risk factors for atherothrombosis, such as diabetes, hypercholesterolaemia, smoking and hypertension, are associated with increased TF expression in circulating monocytes, microparticles and plasma. Several therapies that reduce atherothrombosis, such as statins, ACE inhibitors, beta-blockers and anti-platelet drugs, are associated with reduced TF expression. In addition to its haemostatic and pro-thrombotic functions, the TF : FVIIa complex and downstream coagulation proteases activate cells by cleavage of protease-activated receptors (PARs). In mice, deficiencies in either PAR-1 or PAR-2 reduce cardiac remodelling and heart failure after ischaemia-reperfusion injury. This suggests that inhibition of coagulation proteases and PARs may be protective in heart attack patients. In contrast, the TF/thrombin/PAR-1 pathway is beneficial in a mouse model of Coxsackievirus B3-induced viral myocarditis. We found that stimulation of PAR-1 increases the innate immune response by enhancing TLR3-dependent IFN-β expression. Therefore, inhibition of the TF/thrombin/PAR-1 pathway in patients with viral myocarditis could have detrimental effects. Conclusion: The TF : FVIIa complex has both protective and pathological roles in the heart.
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Therapeutic angiogenesis is a promising strategy for treating ischemia. Our previous work showed that endogenous endothelial tissue factor (TF) expression induces intracrine signaling and switches-on angiogenesis in microvascular endothelial cells (mECs). We have hypothesized that activated mECs could exert a further paracrine regulation through the release of TF-rich microvascular endothelial microparticles (mEMPs) and induce neovascularization of ischemic tissues. Here, we describe for the first time that activated mECs are able to induce reparative neovascularization in ischemic zones by releasing TF-rich microparticles. We show in vitro and in vivo that mEMPs released by both wild-type and TF-upregulated-mECs induce angiogenesis and collateral vessel formation, whereas TF-poor mEMPs derived from TF-silenced mECs are not able to trigger angiogenesis. Isolated TF-bearing mEMPs delivered to nonperfused adductor muscles in a murine hindlimb ischemia model enhance collateral flow and capillary formation evidenced by MRI. TF-bearing mEMPs increase angiogenesis operating via paracrine regulation of neighboring endothelial cells, signaling through the β1-integrin pathway Rac1-ERK1/2-ETS1 and triggering CCL2 production to form new and competent mature neovessels. These findings demonstrate that TF-rich mEMPs released by microvascular endothelial cells can overcome the consequences of arterial occlusion and tissue ischemia by promoting postischemic neovascularization and tissue reperfusion. © 2014 American Heart Association, Inc.
Article
Protein Z (PZ), a vitamin K-dependent plasma protein, dramatically enhances inhibition of coagulation factor Xa by protein Z-dependent protease inhibitor (ZPI), serpinA10 [1]. ZPI also directly inhibits factor XIa [2]. That PZ and ZPI knockout mice show enhanced responses in models of induced thrombosis supports a physiological relevant role for the PZ/ZPI system in the regulation of coagulation [3,4]. © 2012 International Society on Thrombosis and Haemostasis.
Article
Tissue Factor (TF) is expressed in various cell types of the heart, such as cardiomyocytes. In addition to its role in the initiation of blood coagulation, the TF:FVIIa complex protects cells from apoptosis. There are two isoforms of Tissue Factor (TF): "full length" (fl)TF--an integral membrane protein, and alternatively spliced (as)TF--a protein that lacks a transmembrane domain and can thus be secreted in a soluble form. Whether asTF or flTF affects apoptosis of cardiomyocytes is unknown. In this study, we examined whether asTF or flTF protects murine cardiomyocytes from TNF-α-induced apoptosis. We used murine cardiomyocytic HL-1 cells and primary murine embryonic cardiomyocytes that overexpressed either murine asTF or murine flTF, and stimulated them with TNF-α to initiate cell death. Apoptosis was assessed by annexin-V assay, propidium iodide assay, as well as activation of caspase-3 and -9. In addition, signaling via integrins, Akt, NFκB and Erk1/2, and gene-expression of Bcl-2 family members were analyzed. We here report that overexpression of asTF reduced phosphatidylserine exposure upon TNF-α-stimulation. asTF overexpression led to an increased expression and phosphorylation of Akt, as well as up-regulation of the anti-apoptotic protein Bcl-x(L). The anti-apoptotic effects of asTF overexpression were mediated via α(V)β(3)/Akt/NFκB signaling and were dependent on Bcl-x(L) expression in HL-1 cells. The anti-apoptotic activity of asTF was also observed using primary cardiomyocytes. Analogous yet less pronounced anti-apoptotic sequelae were observed due to overexpression of flTF. Importantly, cardiomyocytes deficient in TF exhibited increased apoptosis compared to wild type cells. We propose that asTF and flTF protect cardiomyocytes against TNF-α-induced apoptosis via activation of specific signaling pathways, and up-regulation of anti-apoptotic members of the Bcl-2 protein family.
Article
Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 but it has no enzymatic activity. It is a cofactor of a serpin, the protein Z-dependent protease inhibitor (ZPI), and the complex PZ/ZPI inhibits activated factor X on phospholipid surfaces. In mice, the disruption of PZ or ZPI gene is asymptomatic, but enhances the thrombotic phenotype and mortality of other thrombotic risk factors. Most of the clinical studies focused on PZ. Despite conflicting results, a recent meta-analysis indicated that PZ deficiency could be a risk for venous and arterial thrombosis and early fetal loss. However, these conclusions are drawn from case-control studies of small size, constituting an important limitation. Recently, it was shown that PZ and/or ZPI are synthesised by normal kidney and different cancer cells, suggesting that the complex PZ/ZPI could play a role in inhibiting the tissue deposition of fibrin. The physiopathological consequences of these observations remain to be established. At this time, the measurement of plasma PZ and ZPI or analysis of their gene polymorphisms should not be performed routinely for the exploration of thrombophilia.
Article
Microparticles (MPs) have procoagulant properties as shown in vitro and in animal models. Their role in haemostatic system activation at the site of a vascular injury in vivo in humans has not been studied. In a prospective randomized crossover study, 13 healthy volunteers were given 100 mg acetylsalicylic acid or placebo daily for 7 days. Number and cellular origin, expression of tissue factor (TF) and phosphatidylserine on MPs, and platelet and coagulation activation markers [beta-thromboglobulin (beta-TG), prothrombin fragment f1.2 (f1.2)] were measured in venous blood and in blood from a vascular injury (shed blood) by flow cytometry and immunoassays, respectively. The number of MPs was significantly higher in shed blood than in venous blood. The majority of MPs were platelet derived. The expression of TF on MPs was low, but higher in shed blood than in venous blood. TF positive MPs were significantly higher in shed blood, which was due to an increase of MPs from platelets (PMPs). In shed blood, the number of TF expressing platelet-derived MPs correlated with beta-TG, but not with f1.2. Low dose acetylsalicylic acid did not affect shedding of PMPs, neither in venous blood nor in shed blood. The release of PMPs locally at the site of platelet plug formation in humans indicates a possible role of MPs for haemostatic system activation in vivo. Low dose acetylsalicylic acid might not be strong enough to suppress shedding of PMPs in the microcirculation.
Article
This study was undertaken to assess whether plasmas isolated during off-pump coronary surgery trigger less oxidative stress than those isolated during on-pump surgery. Plasmas were sampled from patients before (TO), just after (TI) and 24 hours after (T2) cardiac surgery (n=24 on-pump and n=10 off-pump). Rings of rat thoracic aortas were incubated for 20 hours with these different plasmas (100 microl + 4 ml medium) or saline (control). Thereafter, superoxide anion production was assessed by chemiluminescence and the mean signal was expressed as percent of that in the control ring. In rat aorta exposed to plasmas from on-pump CABG patients (n=6), the signal was enhanced by 210 +/- 29% at T1 (P < 0.05) and by 174 +/- 29% at T2 (P < 0.05) versus 53 +/- 12% at T0. Moreover, at T1 and T2, there was an upregulation of p22(phox), the key subunit of NADPH oxidase, the main enzyme involved in oxidative stress of the vascular wall. In contrast, off-pump plasmas did not induce this superoxide production. Incubation with microparticles obtained by ultracentrifugation also markedly enhanced the signal at T1 and T2 (vs. T0) in the on-pump group (but not in the off-pump group). Selective removal of CD34, CD105, CD59, CD146, CD42 microparticles using flow cytometry did not abolish the signal. CRP and SAA plasma levels were enhanced only at T2 in both groups. Plasmas isolated after on-pump but not off-pump coronary bypass surgery can induce superoxide generation by the vascular wall which seems related to circulating microparticles remaining present at least 24 hours after the procedure that might be of endothelial origin.
Article
The relation of minor and major axes of the left ventricle was determined in 100 left ventriculograms performed in the right anterior oblique projection. This relation taken over a wide range of volumes was used to derive a theoretically correct equation for determination of ventricular volume by echocardiography. The final equation was: V =[7.0/2.4 +d] (D3), where V = volume and D = the echocardiographically measured internal dimension. In 12 patients without asynergy, this equation accurately and directly calculated end-systolic and end-diastolic volumes whether the left ventricle was small or large. However, in 12 patients exhibiting left ventricular asynergy the correlation between angiographically and echocardiographically determined volumes was poor. Thus, caution is recommended in the use of time-motion echocardiography to calculate ventricular volumes in patients with coronary artery disease and possible left ventricular asynergy.
Article
In this tutorial article, the concepts of correlation and regression are reviewed and demonstrated. The authors review and compare two correlation coefficients, the Pearson correlation coefficient and the Spearman rho, for measuring linear and nonlinear relationships between two continuous variables. In the case of measuring the linear relationship between a predictor and an outcome variable, simple linear regression analysis is conducted. These statistical concepts are illustrated by using a data set from published literature to assess a computed tomography-guided interventional technique. These statistical methods are important for exploring the relationships between variables and can be applied to many radiologic studies.
Article
Elevated plasma levels of endothelial microparticles (EMPs) are associated with the presence of clinical atherosclerosis. Considering the anti-inflammatory properties of HMG-CoA reductase inhibitors on the endothelium, we studied the effect of fluvastatin on the release of EMPs in cultured human coronary artery endothelial cells (HCAEC). EMPs were generated in TNF-alpha-activated HCAECs. The absolute number of EMPs was enumerated using a novel two-color flow cytometric immunostaining technique with TruCount beads as an internal reference. EMPs are defined as EC membrane vesicles (1-2 microm in size) with a characteristic immunophenotype. The addition of fluvastatin to TNF-alpha-activated HCAECs significantly suppressed EMP release. Fluvastatin suppressed TNF-alpha-induced Rho activation. The Rho-kinase inhibitor, Y-27632, reproduced the effect of statin. EMP release from TNF-alpha-activated HCAECs is suppressed by fluvastatin. In addition, the Rho/Rho-kinase may play an important role in modulating EMP release.
Article
Activation of coagulation, fibrinolysis, and the vascular endothelium occurs after heart surgery with cardiopulmonary bypass (CPB), but the effects of eliminating CPB in patients undergoing coronary artery bypass grafting (CABG) are unknown. Therefore, we compared the hemostatic profiles of off-pump and on-pump CABG patients. Two groups of consecutive patients participating in a larger trial (the Octopus Trial) were randomly allocated to undergo CABG with (n = 20) or without (n = 20) CPB. Platelet numbers and plasma concentrations of P-selectin, prothrombin fragment 1.2 (F1.2), soluble fibrin, d-dimers, and von Willebrand factor (as a marker of endothelial cell activation) were measured and corrected for hemodilution. Compared with the on-pump CABG group, F1.2 and d-dimer levels were significantly lower (P = 0.004 and P = 0.03, respectively) in patients having CABG surgery performed off-pump. In the CPB group, F1.2 (median [interquartile range], 450% of baseline [233%-847%]) and d-dimer (538% [318%-1192%]) peaked in the immediate postoperative period and remained increased until Day 4, whereas in the off-pump group, F1.2 and d-dimer levels increased more gradually and peaked on Day 4 (342% [248%-515%] and 555% [387%-882%], respectively). In both groups, von Willebrand factor concentrations were increased until Day 4 (CPB, 308% [228%-405%]; off-pump, 288% [167%-334%]). Despite heparinization, CABG surgery with CPB was associated with excessive thrombin generation and fibrinolytic activity immediately after surgery. The off-pump group demonstrated a delayed postoperative response that became equal in magnitude to the CPB in the later (20-96 h) postoperative period.
Article
Circulating microparticles of various cell types are present in healthy individuals and, in varying numbers and antigenic composition, in various disease states. To what extent these microparticles contribute to coagulation in vivo is unknown. To examine the in vivo thrombogenicity of human microparticles. Microparticles were isolated from pericardial blood of cardiac surgery patients and venous blood of healthy individuals. Their numbers, cellular source, and tissue factor (TF) exposure were determined using flow cytometry. Their in vitro procoagulant properties were studied in a fibrin generation test, and their in vivo thrombogenicity in a rat model. The total number of microparticles did not differ between pericardial samples and samples from healthy individuals (P = 0.786). In both groups, microparticles from platelets, erythrocytes, and granulocytes exposed TF. Microparticle-exposed TF antigen levels were higher in pericardial compared with healthy individual samples (P = 0.036). Pericardial microparticles were strongly procoagulant in vitro and highly thrombogenic in a venous stasis thrombosis model in rats, whereas microparticles from healthy individuals were not [thrombus weights 24.8 (12.2-41.3) mg vs. 0 (0-24.3) mg median and range; P < 0.001]. Preincubation of pericardial microparticles with an inhibitory antibody against human TF abolished their thrombogenicity [0 (0-4.4) mg; P < 0.01], while a control antibody had no effect [19.6 (12.6-53.7) mg; P > 0.05]. The thrombogenicity of the microparticles correlated strongly with their TF exposure (r = 0.9524, P = 0.001). Human cell-derived microparticles promote thrombus formation in vivo in a TF-dependent manner. They might be the direct cause of an increased thromboembolic tendency in various patient groups.
Article
Platelet activation is accompanied by the release of microparticles. However, little is known about the role of platelet-derived microparticles (PMP) in the regulation of angiogenesis and related clinical situations. The aim of our study was to evaluate the effect of PMP on angiogenesis and to analyze its mechanisms. Both in vitro (rat aortic ring model, cell invasion test) and in vivo (agarose bead transplantation, artificial cardiac ischemia in Sabra rats) approaches were used in the study. A dose-dependent pro-angiogenic effect of PMP was observed in the rat aortic ring model. This effect could be eliminated by inhibition of VEGF, bFGF, and PDGF, but not heparanase. PMP exerted their effect via PI 3-kinase, Src kinase, and ERK, whereas protein kinase C and p38 were not involved. Moreover, PMP induced invasion of endothelial cells through a layer of matrigel. This effect was mediated by VEGF, heparanase, and PDGF, but not bFGF. Furthermore, PMP induced angiogenesis in an in vivo model in which agarose beads containing PMP were transplanted subcutaneously into mice. In addition, the effect of PMP on angiogenesis was evaluated in the model of in vivo chronic myocardial ischemia in rats. Ischemia induced a decrease in the number of functioning capillaries (34+/-21.5 vs. 157+/-42.0 per view field), but their amount increased after injection of PMP into the myocarium (97+/-27.3; p<0.001 vs. ischemia without PMP). PMP induce angiogenesis both in vitro and in vivo. Injection of PMP into the ischemic myocardium might improve the process of revascularization after chronic ischemia.
Article
We hypothesized that off-pump coronary artery bypass grafting has less impact on the hemostatic systems than on-pump surgery. Thirty-one patients were randomized to on-pump or off-pump coronary artery bypass grafting. Factors of hemostasis as well as markers of endothelial activation were measured up to 24 hours after the operation: Fibrin D dimer, prothrombin fragment 1+2, alpha2-macroglobulin, protein C1 esterase inhibitor, fibronectin, and von Willebrand factor. Overall hemostasis potential, overall coagulation potential, and overall fibrinolysis potential were determined with a previously developed assay. We also measured platelet count before and after surgery. Fibrin D dimer and prothrombin fragment 1+2 concentrations were lower during surgery in the off-pump group (p < 0.001). Four hours after admission to the intensive care unit, these differences were eliminated. alpha2-macroglobulin, protein C1 esterase inhibitor, fibronectin, and von Willebrand factor concentrations did not differ between groups (p = 0.59, p = 0.28, p = 0.22, and p = 0.69). Protein C1 esterase inhibitor and von Willebrand factor concentrations increased over time (p < 0.001) in both groups. Overall hemostasis potential and overall coagulation potential increased over time (p < 0.001), while overall fibrinolysis potential decreased (p < 0.001) with no difference between groups (p = 0.69, p = 0.91). Platelet count decreased on the first postoperative day (p < 0.001), but increased from the first to the third postoperative day (p = 0.004) in both groups without any inter group difference (p = 0.82). There was a tendency toward less activation of coagulation and fibrinolysis in low-risk patients during elective off-pump coronary artery bypass surgery when compared with on-pump surgery.
Article
Protein Z (PZ) is a vitamin K-dependent protein isolated from human plasma, and acts as a cofactor for a serpin, called protein Z-dependent protease inhibitor (ZPI). A prothrombotic phenotype has been reported in PZ deficient mice, and PZ deficiencies have been observed in patients with arterial thrombotic events. PZ was immunologically detected in the endothelium of atherosclerotic arteries, suggesting that endothelial cells could be involved in the production of PZ. In this study we analyzed the synthesis and release of PZ and ZPI by human umbilical vein endothelial cells (HUVEC), representative of the macrovasculature, and by HMEC-1, a microvascular endothelial cell line. PZ was quantified by a specific ELISA in the supernatant and in the lysates of both cellular types. Western blotting of the supernatants showed the presence of a band of 62 kDa, identical to PZ synthesized by the hepatoma cell line HepG2. mRNA of PZ was also detected in each cellular type. PZ biosynthesis was unaffected by inflammatory cytokines in HUVEC, whereas a slight decrease of mRNA and PZ antigen (53.5 +/- 14.5% of protein synthesis as compared to the control, p < 0.01) and a modest increase (126 +/- 8.5% as compared to the control, p < 0.05) were induced respectively byTumor Necrosis Factor (TNF)-alpha (25 ng/ml) and oncostatin M (5 ng/ml) in HMEC-1. Immunological studies showed the presence of PZ near the nucleus and a possible expression of PZ at the membrane. In addition, PZ was present in the endothelial cells of both normal arterial and venous vessel sections. In contrast, neither ZPI nor its mRNA was detected in endothelial cells.
Executive summary: heart disease and stroke statistics—2016 update: a report from the American Heart Association
  • D Mozaffarian
  • Benjamin
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