Validation of the vitronectin knockout mouse as a model for studying myocardial infarction: Vitronectin appears to influence left ventricular remodelling following myocardial infarction

BACKGROUND:

Vitronectin (VN) is an abundant acute-phase plasma protein that regulates cell adhesion and migration as well as interactions with components of the plasminogen activator/plasmin system, specifically plasminogen activator inhibitor type 1. This system plays a major role in tissue remodelling regulating wound healing after myocardial infarction.

OBJECTIVES:

To investigate the feasibility of using VN knockout mice (VN^−/−) to study the role of VN on ventricular remodelling following myocardial infarction.

METHODS:

Specifically bred VN^−/− mice and normal wild-type (VN^+/+) mice underwent coronary artery ligation and were assessed 28 days postligation using echocardiography and morphometric histology.

RESULTS:

No difference was observed between VN^−/− mice and VN^+/+ mice with respect to gross phenotype, weight, coronary anatomy or echocardiographically measured ejection fraction (56%). Following myocardial infarction, VN^−/− mice exhibited less ventricular dilation and less impairment in echocardiographic ejection fraction compared with VN^+/+ mice (48% versus 41%; P=0.01). VN^−/− mice also exhibited smaller infarcts on morphometric analysis.

CONCLUSIONS:

The results of the present study confirmed the feasibility of using coronary artery ligation in VN knockout mice to investigate the role of VN in post-myocardial infarction remodelling. The absence of VN appears to result in favourable effects on wound healing. These data suggest that this model may offer novel insights into the role of VN in the regulation of myocardial remodelling.     

Elevated procoagulant microparticles expressing endothelial and platelet markers in essential thrombocythemia

Background

Most cell types, including blood - and vascular cells, produce microparticles upon activation. Since cellular microparticles are known to be elevated in thromboembolic diseases, we hypothesized a role for microparticles in the pathogenesis of thrombosis in essential thrombocythemia.

Design and Methods

In plasma samples from 21 patients with essential thrombocythemia and ten healthy subjects, the levels and the cellular origin of microparticles were determined by flowcytometric analysis, while the microparticle-associated procoagulant activity was measured using a thrombin generation assay.

Results

Patients with essential thrombocythemia had significantly higher numbers of circulating annexin V-positive microparticles than controls (median 4500 vs. 2500×10⁶ events/L; p=0.039), including significantly higher numbers of microparticles positive for the platelet marker CD61 (p=0.043), the endothelial markers CD62E (p=0.009) and CD144 (p=0.021), and for tissue factor (p=0.036). CD62E was co-expressed with the platelet marker CD41 on microparticles, suggesting a bilineage origin of such microparticles, which were observed only in patients with risk factors for thrombosis. Patients with essential thrombocythemia had higher plasma levels of mature von Willebrand factor (p=0.045) but similar propeptide levels compared to controls. In thrombin generation analyses, microparticle-rich plasma from patients with essential thrombocythemia had a shorter lag time (p=0.001) and higher peak height (p=0.038) than plasma from controls. Peak height correlated significantly with the total number of microparticles (R=0.634, p<0.001).

Conclusions

Patients with essential thrombocythemia had higher number of circulating microparticles with platelet and endothelial markers, suggesting ongoing platelet and endothelial activation. This was confirmed by an increased level of mature von Willebrand factor, an abnormal mature von Willebrand factor/propeptide ratio, and a hypercoagulable state reflected in thrombin generation. These findings suggest a role for microparticles in thrombosis in essential thrombocythemia.     

Tissue factor-expressing monocytes inhibit fibrinolysis through a TAFI-mediated mechanism, and make clots resistant to heparins

Background

Thrombin is the main activator of the fibrinolysis inhibitor TAFI (thrombin activatable fibrinolysis inhibitor) and heightened clotting activation is believed to impair fibrinolysis through the increase of thrombin activatable fibrinolysis inhibitor activation. However, the enhancement of thrombin generation by soluble tissue factor was reported to have no effect on plasma fibrinolysis and it is not known whether the same is true for cell-associated tissue factor. The aim of this study was to evaluate the effect of tissue factor-expressing monocytes on plasma fibrinolysis in vitro.

Design and Methods

Tissue factor expression by human blood mononuclear cells (MNC) and monocytes was induced by LPS stimulation. Fibrinolysis was spectrophotometrically evaluated by measuring the lysis time of plasma clots containing LPS-stimulated or control cells and a low concentration of exogenous tissue plasminogen activator.

Results

LPS-stimulated MNC (LPS-MNC) prolonged fibrinolysis time as compared to unstimulated MNC (C-MNC) in contact-inhibited but not in normal citrated plasma. A significantly prolonged lysis time was observed using as few as 30 activated cells/μL. Fibrinolysis was also impaired when clots were generated on adherent LPS-stimulated monocytes. The antifibrinolytic effect of LPS-MNC or LPS-monocytes was abolished by an anti-tissue factor antibody, by an antibody preventing thrombin-mediated thrombin activatable fibrinolysis inhibitor activation, and by a TAFIa inhibitor (PTCI). Assays of thrombin and TAFIa in contact-inhibited plasma confirmed the greater generation of these enzymes in the presence of LPS-MNC. Finally, the profibrinolytic effect of unfractionated heparin and enoxaparin was markedly lower (~50%) in the presence of LPS-MNC than in the presence of a thromboplastin preparation displaying an identical tissue factor activity.

Conclusions

Our data indicate that LPS-stimulated monocytes inhibit fibrinolysis through a tissue factor-mediated enhancement of thrombin activatable fibrinolysis inhibitor activation and make clots resistant to the profibrinolytic activity of heparins, thus providing an additional mechanism whereby tissue factor-expressing monocytes/macrophages may favor fibrin accumulation and diminish the antithrombotic efficacy of heparins.     

Risk factors for coronary artery sclerosis in patients with diabetes

OBJECTIVE:

To examine risk factors for coronary artery sclerosis in patients with diabetes mellitus.

METHODS:

Patients with diabetes were divided into two groups based on whether their electrocardiogram (ECG) showed ischemic changes. In addition to traditional risk factors, other parameters (ie, serum levels of serotonin, homocysteine, thrombomodulin, plasminogen activator inhibitor-1, tissue plasminogen activator, vascular endothelial growth factor, intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and endothelial-leukocyte adhesion molecule-1) were measured in both groups.

RESULTS:

In the group with ischemic ECG changes (n=13), systolic blood pressure was significantly higher than in the group with no changes (n=18). There were no significant differences in the serum levels of other factors; however, body mass index, hemoglobin A1c, total cholesterol, low density lipoprotein cholesterol and triglyceride levels tended to be higher in the group with ischemic ECG changes.

CONCLUSIONS:

Although the sample of patients was limited, these results suggest that strict control of traditional risk factors, especially high blood pressure, is important for preventing coronary artery sclerosis in patients with diabetes mellitus.     

Procoagulant activity of circulating microparticles is associated with the presence of moderate calcified plaque burden detected by multislice computed tomography

Background Circulating microparticles （MPs） have been reported to be associated with coronary artery disease （CAD）. In this study, we explored the relationship between MPs procoagulant activity and characteristics of atherosclerotic plaque detected by 64-slice computed tomography angiography （CTA）. Methods In 127 consecutive patients with CAD but without acute coronary syndrome and who under went 64-slice CTA, MPs procoagulant activity in plasma Coy a thrombin generation test）, soluble form of lectin-like oxidized low-density lipoprotein receptor-1 （sLOX-1） and N（epsilon）-（carboxymethyl） lysine （CML） circulating levels （by ELISA） were measured. A quantitative volumetric analysis of the lumen and plaque burden of the vessel wall （soft and calcific components）, for the three major coronary vessels, was performed. The patients were classified in three groups according to the presence of calcium volume： non-calcified plaque （NCP） group （calcium volume （%） = 0）, moderate calcified plaque （MCP） group （0 〈 calcium volume （%） 〈 1）, and calcified plaque （CP） group （calcium volume （%） 〉 1）. Results MPs procoagulant activity and CML levels were higher in MCP group than in CP or NCP group （P = 0.009 and P = 0.027, respectively）. MPs procoagulant activity was positively associated with CML （r = 0.317, P 〈 0.0001） and sLOX-1 levels （r = 0.216, P = 0.0025）. Conclusions MPs procoagulant activity was higher in the MCP patient group and correlated positively with sLOX-1 and CML levels, suggesting that it may characterize a state of blood vulnerability that may locally precipitate plaque instability and increase the risk of subsequent major cardiovascular events.     

Circulating erythrocyte-derived microparticles are associated with coagulation activation in sickle cell disease

Background

Sickle cell disease is characterized by a hypercoagulable state as a result of multiple factors, including chronic hemolysis and circulating cell-derived microparticles. There is still no consensus on the cellular origin of such microparticles and the exact mechanism by which they may enhance coagulation activation in sickle cell disease.

Design and Methods

In the present study, we analyzed the origin of circulating microparticles and their procoagulant phenotype during painful crises and steady state in 25 consecutive patients with sickle cell disease.

Results

The majority of microparticles originated from platelets (GPIIIa,CD61) and erythrocytes (glycophorin A,CD235), and their numbers did not differ significantly between crisis and steady state. Erythrocyte-derived microparticles strongly correlated with plasma levels of markers of hemolysis, i.e. hemoglobin (r=−0.58, p<0.001) and lactate dehydrogenase (r=0.59, p<0.001), von Willebrand factor as a marker of platelet/endothelial activation (r=0.44, p<0.001), and D-dimer and prothrombin fragment F1+2 (r=0.52, p<0.001 and r=0.59, p<0.001, respectively) as markers of fibrinolysis and coagulation activation. Thrombin generation depended on the total number of microparticles (r=0.63, p<0.001). Anti-human factor XI inhibited thrombin generation by about 50% (p<0.001), whereas anti-human factor VII was ineffective (p>0.05). The extent of factor XI inhibition was associated with erythrocyte-derived microparticles (r=0.50, p=0.023).

Conclusions

We conclude that the procoagulant state in sickle cell disease is partially explained by the factor XI-dependent procoagulant properties of circulating erythrocyte-derived microparticles.     

Anti-Phospholipase A2 Receptor Antibodies Correlate with Clinical Status in Idiopathic Membranous Nephropathy

Summary

Background and objectives

Circulating autoantibodies against the M-type phospholipase A₂ receptor (anti-PLA₂R) were recently identified in the majority of patients in the United States with idiopathic membranous nephropathy (iMN). The objectives of this study were to assess the prevalence of anti-PLA₂R in a separate, European cohort of iMN patients and to correlate the presence of anti-PLA₂R with clinical parameters reflective of disease activity.

Design, setting, participants, & measurements

Anti-PLA₂R levels were blindly assessed by a Western blot immunoassay in 54 serum samples from 18 patients with iMN collected in various stages of clinical disease. Anti-PLA₂R levels were correlated with other clinical parameters.

Results

77.8% of iMN patients in our cohort had antibodies reactive with human PLA₂R. The antibody levels in these patients correlated strongly with both clinical status and proteinuria (r = 0.73, P < 0.01).

Conclusions

The role of PLA₂R as a major antigen in iMN was confirmed in an independent, European patient cohort, and levels of circulating anti-PLA₂R revealed a strong correlation with clinical disease activity. We propose that detection and measurement of these autoantibodies may provide a tool for monitoring of disease activity and treatment efficacy.     

Induction of insulin resistance by the adipokines resistin, leptin, plasminogen activator inhibitor-1 and retinol binding protein 4 in human megakaryocytes

Background

In normal platelets, insulin inhibits agonist-induced Ca²⁺ mobilization by raising cyclic AMP. Platelet from patients with type 2 diabetes are resistant to insulin and show increased Ca²⁺ mobilization, aggregation and procoagulant activity. We searched for the cause of this insulin resistance.

Design and Methods

Platelets, the megakaryocytic cell line CHRF-288-11 and primary megakaryocytes were incubated with adipokines and with plasma from individuals with a disturbed adipokine profile. Thrombin-induced Ca²⁺ mobilization and signaling through the insulin receptor and insulin receptor substrate 1 were measured. Abnormalities induced by adipokines were compared with abnormalities found in platelets from patients with type 2 diabetes.

Results

Resistin, leptin, plasminogen activator inhibitor-1 and retinol binding protein 4 left platelets unchanged but induced insulin resistance in CHRF-288-11 cells. Interleukin-6, tumor necrosis factor-α and visfatin had no effect. These results were confirmed in primary megakaryocytes. Contact with adipokines for 2 hours disturbed insulin receptor substrate 1 Ser³⁰⁷-phosphorylation, while contact for 72 hours caused insulin receptor substrate 1 degradation. Plasma with a disturbed adipokine profile also made CHRF-288-11 cells insulin-resistant. Platelets from patients with type 2 diabetes showed decreased insulin receptor substrate 1 expression.

Conclusions

Adipokines resistin, leptin, plasminogen activator-1 and retinol binding protein 4 disturb insulin receptor substrate 1 activity and expression in megakaryocytes. This might be a cause of the insulin resistance observed in platelets from patients with type 2 diabetes.     

Relationship of treatment delays and mortality in patients undergoing fibrinolysis and primary percutaneous coronary intervention. The Global Registry of Acute Coronary Events

Objective

Treatment delays may result in different clinical outcomes in patients with ST‐segment elevation myocardial infarction (STEMI) who receive fibrinolytic therapy vs primary percutaneous coronary intervention (PCI). The aim of this analysis was to examine how treatment delays relate to 6‐month mortality in reperfusion‐treated patients enrolled in the Global Registry of Acute Coronary Events (GRACE).

Design

Prospective, observational cohort study.

Setting

106 hospitals in 14 countries.

Patients

3959 patients who presented with STEMI within 6 h of symptom onset and received reperfusion with either a fibrin‐specific fibrinolytic drug or primary PCI.

Main outcome measures

6‐month mortality.

Methods

Multivariable logistic regression was used to assess the relationship between outcomes and treatment delay separately in each cohort, with time modelled with a quadratic term after adjusting for covariates from the GRACE risk score.

Results

A total of 1786 (45.1%) patients received fibrinolytic therapy, and 2173 (54.9%) underwent primary PCI. After multivariable adjustment, longer treatment delays were associated with a higher 6‐month mortality in both fibrinolytic therapy and primary PCI patients (p<0.001 for both cohorts). For patients who received fibrinolytic therapy, 6‐month mortality increased by 0.30% per 10‐min delay in door‐to‐needle time between 30 and 60 min compared with 0.18% per 10‐min delay in door‐to‐balloon time between 90 and 150 min for patients undergoing primary PCI.

Conclusions

Treatment delays in reperfusion therapy are associated with higher 6‐month mortality, but this relationship may be even more critical in patients receiving fibrinolytic therapy.Treatment delays in the delivery of fibrinolytic therapy and primary percutaneous coronary intervention (PCI) are associated with increased rates of mortality in patients with ST‐segment elevation myocardial infarction (STEMI).^1,2 However, there is controversy as to whether treatment delays in primary PCI are less important than those in fibrinolytic therapy, especially when fibrin‐specific agents are utilised.³ This is important because a differential effect of treatment delays on outcomes may influence the selection between these two reperfusion strategies.^3,4,5,6,7 Accordingly, using data from the ongoing, multinational Global Registry of Acute Coronary Events (GRACE), we examined how treatment delays relate to 6‐month mortality in patients with STEMI who received fibrinolytic therapy with a fibrin‐specific agent or primary PCI. GRACE provides an ideal resource for such an investigation because it includes patients who received both types of reperfusion strategies, and the data for each strategy are collected under identical circumstances.     

Altered lysophosphatidic acid (LPA) receptor expression during hepatic regeneration in a mouse model of partial hepatectomy

Background

Hepatic regeneration requires coordinated signal transduction for efficient restoration of functional liver mass. This study sought to determine changes in lysophosphatidic acid (LPA) and LPA receptor (LPAR) 1–6 expression in regenerating liver following two-thirds partial hepatectomy (PHx).

Methods

Liver tissue and blood were collected from male C57BL/6 mice following PHx. Circulating LPA was measured by enzyme-linked immunosorbent assay (ELISA) and hepatic LPAR mRNA and protein expression were determined.

Results

Circulating LPA increased 72 h after PHx and remained significantly elevated for up to 7 days post-PHx. Analysis of LPAR expression after PHx demonstrated significant increases in LPAR1, LPAR3 and LPAR6 mRNA and protein in a time-dependent manner for up to 7 days post-PHx. Conversely, LPAR2, LPAR4 and LPAR5 mRNA were barely detected in normal liver and did not significantly change after PHx. Changes in LPAR1 expression were confined to non-parenchymal cells following PHx.

Conclusions

Liver regeneration following PHx is associated with significant changes in circulating LPA and hepatic LPAR1, LPAR3 and LPAR6 expression in a time- and cell-dependent manner. Furthermore, changes in LPA–LPAR post-PHx occur after the first round of hepatocyte division is complete.     

Endothelial cell-derived microparticles induce plasmacytoid dendritic cell maturation: potential implications in inflammatory diseases

Background

Increased circulating endothelial microparticles, resulting from vascular endothelium dysfunction, and plasmacytoid dendritic cell activation are both encountered in common inflammatory disorders. The aim of our study was to determine whether interactions between endothelial microparticles and plasmacytoid dendritic cells could contribute to such pathologies.

Design and Methods

Microparticles generated from endothelial cell lines, platelets or activated T cells were incubated with human plasmacytoid dendritic cells sorted from healthy donor blood or with monocyte-derived dendritic cells. Dendritic cell maturation was evaluated by flow cytometry, cytokine secretion as well as naive T-cell activation and polarization. Labeled microparticles were also used to study cellular interactions.

Results

Endothelial microparticles induced plasmacytoid dendritic cell maturation. In contrast, conventional dendritic cells were resistant to endothelial microparticle-induced maturation. In addition to upregulation of co-stimulatory molecules, endothelial microparticle-matured plasmacytoid dendritic cells secreted inflammatory cytokines (interleukins 6 and 8, but no interferon-α) and also induced allogeneic naive CD4⁺ T cells to proliferate and to produce type 1 cytokines such as interferon-γ and tumor necrosis factor-α. Endothelial microparticle endocytosis by plasmacytoid dendritic cells appeared to be required for plasmacytoid dendritic cell maturation. Importantly, the ability of endothelial microparticles to induce plasmacytoid dendritic cells to mature was specific as microparticles derived from activated T cells or platelets (the major source of circulating microparticules in healthy subjects) did not induce such plasmacytoid dendritic cell maturation.

Conclusions

Our data show that endothelial microparticles specifically induce plasmacytoid dendritic cell maturation and production of inflammatory cytokines. This novel activation pathway may be implicated in various inflammatory disorders and endothelial microparticles could be an important immunmodulatory therapeutic target.     

Determining the association between adipokine expression in multiple tissues and phenotypic features of non-alcoholic fatty liver disease in obesity

Objectives:

Non-alcoholic fatty liver disease (NAFLD) is an obesity-associated disease, and in obesity adipokines are believed to be involved in the development of NAFLD. However, it is still not clear whether adipokines in the liver and/or adipose tissues can be related to the development of specific characteristics of NAFLD, such as steatosis and inflammation. We aimed to address this question by simultaneously examining the adipokine expression in three tissue types in obese individuals.

Methods:

We enrolled 93 severely obese individuals with NAFLD, varying from simple steatosis to severe non-alcoholic steatohepatitis. Their expression of 48 adipokines in the liver, visceral and subcutaneous adipose tissue (SAT) was correlated to their phenotypic features of NAFLD. We further determined whether the correlations were tissue specific and/or independent of covariates, including age, sex, obesity, insulin resistance and type 2 diabetes (T2D).

Results:

The expression of adipokines showed a liver- and adipose tissue-specific pattern. We identified that the expression of leptin, angiopoietin 2 (ANGPT2) and chemerin in visceral adipose tissue (VAT) was associated with different NAFLD features, including steatosis, ballooning, portal and lobular inflammation. In addition, the expression of tumor necrosis factor (TNF), plasminogen activator inhibitor type 1 (PAI-1), insulin-like growth factor 1 (somatomedin C) (IGF1) and chemokine (C-X-C motif) ligand 10 (CXCL10) in the liver tissue and the expression of interleukin 1 receptor antagonist (IL1RN) in both the liver and SAT were associated with NAFLD features. The correlations between ANGPT2 and CXCL10, and NAFLD features were dependent on insulin resistance and T2D, but for the other genes the correlation with at least one NAFLD feature remained significant after correcting for the covariates.

Conclusions:

Our results suggest that in obese individuals, VAT-derived leptin and chemerin, and hepatic expression of TNF, IGF1, IL1RN and PAI-1 are involved in the development of NAFLD features. Further, functional studies are warranted to establish a causal relationship.     

Coagulability in obstructive sleep apnea

BACKGROUND:

Obstructive sleep apnea (OSA) is a common disorder that affects both quality of life and cardiovascular health. The causal link between OSA and cardiovascular morbidity/mortality remains elusive. One possible explanation is that repeated episodes of nocturnal hypoxia lead to a hypercoagulable state that predisposes patients to thrombotic events. There is evidence supporting a wide array of hematological changes that affect hemostasis (eg, increased hematocrit, blood viscosity, platelet activation, clotting factors and decreased fibrinolytic activity).

OBJECTIVE:

To provide a comprehensive review of the current evidence associating OSA with increased coagulability, and to highlight areas for future research.

METHODS:

Keyword searches in Ovid Medline were used to identify relevant articles; all references in the articles were searched for relevant titles. The Web of Science was used to identify articles citing the relevant articles found using the Ovid Medline search. All original peer-reviewed articles, meta-analyses and systematic reviews regarding the pertinent topics between 1990 and present were selected for review.

RESULTS:

Hematocrit, blood viscosity, certain clotting factors, tissue factor, platelet activity and whole blood coagulability are increased in patients with OSA, while fibrinolysis is impaired.

CONCLUSION:

There is considerable evidence that OSA is associated with a procoagulant state. Several factors are involved in the procoagulant state associated with OSA. There is a need for adequately powered clinical studies involving well-matched control groups to address potential confounding variables, and to accurately delineate the individual factors involved in the procoagulant state associated with OSA and their response to treatment.     

Thrombolytic therapy is effective in paroxysmal nocturnal hemoglobinuria: a series of nine patients and a review of the literature

Background

Thrombosis is the major risk factor for death in patients with paroxysmal nocturnal hemoglobinuria. Previous case reports indicate that venous thrombosis in patients with paroxysmal nocturnal hemoglobinuria is amenable to thrombolysis.

Design and Methods

We reviewed the outcome of thrombolytic therapy for patients with paroxysmal nocturnal hemoglobinuria who had thromboses refractory to anticoagulation at our institutions.

Results

In this study of 41 patients who had at least one thrombotic event, we confirmed a very high incidence of recurrence despite anticoagulation. Nine patients with thrombosis were regarded as eligible for administration of intravenous tissue plasminogen activator, which was effective in reversing thrombi in all of 15 occasions in which it was given. Serious hemorrhagic complications developed in three cases. At last follow-up visit, of the nine patients treated, three had died, and six were in very good to excellent condition in terms of clinical outcome and radiological findings. The only patient in whom thrombolysis may have contributed to a fatal outcome also had complications of “heparin induced thrombocytopenia with thrombosis”, which we diagnosed in three additional patients. In our review of the literature, nine out of 15 patients treated with thrombolysis have had a good outcome.

Conclusions

Although it is associated with a significant but manageable risk of bleeding, systemic thrombolysis is a highly effective treatment for reversing venous thromboses in patients with paroxysmal nocturnal hemoglobinuria.     

Thrombolysis for Acute Stroke in Hemodialysis: International Survey of Expert Opinion

Summary

Background and objectives

Although data are absent, it has been stated that thrombolysis is probably not safe in the treatment of acute stroke in patients undergoing hemodialysis. The objective of this study was for stroke experts to define the range of management concerning thrombolytic treatment of acute stroke in hemodialysis.

Design, setting, participants, & measurements

Sixty-five stroke experts in thrombolytic therapy of acute ischemic stroke were queried regarding their personal experience in the use of thrombolysis in hemodialysis patients. Hypothetical case scenarios were presented.

Results

Of the 65 stroke experts who were queried, 40 (62%) responded. One-third of the responders had previously treated hemodialysis patients with recombinant tissue-type plasminogen activator (rt-PA). Most favored use of intravenous rt-PA for hemodialysis patients with acute ischemic stroke. When presented with a case of a patient who had recently undergone dialysis with a mildly prolonged activated partial thromboplastin time (aPTT), 50% favored immediate intravenous thrombolysis. Seventy-eight percent of the experts would have considered an intra-arterial approach and would have preferred mechanical clot retrieval to thrombolysis.

Conclusions

Despite the acknowledged absence of data and prevalent concerns about bleeding risk, most surveyed experts favored its use. One-third reported treating hemodialysis patients with this therapy. Although these results do not substitute for data, they usefully define the range of current practice of stroke experts.     

Systematic review of fibrinolytic-facilitated percutaneous coronary intervention: Potential benefits and future challenges

BACKGROUND:

Facilitated percutaneous coronary intervention (PCI) is defined as the administration of fibrinolytic therapy and/or glycoprotein (GP) IIb/IIIa inhibitors to minimize myocardial ischemia time while waiting for PCI. A pooled meta-analysis suggested that facilitated PCI was associated with higher rates of mortality and morbidity compared with nonfacilitated PCI.

OBJECTIVE:

The heterogeneous and complex trials of facilitated PCI were systematically reviewed to identify where this strategy may be beneficial and deserving of further research.

METHODS:

MEDLINE, EMBASE, the Cochrane database, the Internet and conference proceedings were searched to obtain relevant trials. Human studies that randomly assigned patients to fibrinolytic-facilitated PCI (administration of fibrinolytic therapy alone or in combination with GP IIb/IIIa inhibitors before angiography) versus nonfacilitated PCI were included.

RESULTS:

Nine trials encompassing 3836 patients were reviewed. The facilitated PCI strategy was fibrinolytic therapy alone in seven trials and half-dose fibrinolytic therapy plus GP IIb/IIIa inhibitors in two trials. In patients who had fibrinolysis less than 2 h after symptom onset (mainly in the prehospital setting) and/or slightly delayed PCI 3 h to 24 h after fibrinolysis, facilitated PCI was associated with the greatest Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow and a trend toward reduced mortality. Overall, facilitated PCI was associated with increased intracranial hemorrhage and reinfarction. Combining half-dose fibrinolytic therapy and GP IIb/IIIa inhibitors reduced reinfarction but increased major bleeding.

CONCLUSIONS:

Facilitated PCI cannot be recommended outside of experimental protocols at this time. Further research should focus on selecting patients with higher benefit-to-risk ratios and performing prehospital fibrinolysis with optimal antiplatelet or antithrombin therapy, as well as slightly delayed PCI in patients who are stable or geographically removed from PCI facilities.     

Recombinant tissue plasminogen activator plus heparin compared with heparin alone for patients with acute submassive pulmonary embolism: one-year outcome

Objective To evaluate the long-term effects of thrombolysis on patients with submassive pulmonary embolism (PE). Methods Data of 136 patients with acute submassive PE and low risk of bleeding were prospectively collected from January 2005 to October 2011 in a single medical center. Patients received recombinant tissue plasminogen activator (r-tPA) plus low molecular weight heparin (LMWH, TT group, n = 79) or LMWH alone (AT group, n = 57), depending on treating physician’s recommendation and patient’s preference. Echocardiography was performed at admission, 24 h, 6 and 12 months to evaluate right ventricular function. Computed tomography pulmonary angiography (CTPA) and lung perfusion scan were performed on admission, at 7 days, 6 and 12 months to evaluate clot burden. Results Seventy-nine patients received r-tPA plus LMWH (TT group) while 57 received LMWH alone (AT group). The baseline characteristics and risk factors did not differ between the two groups. Respiratory rate, heart rate, and systolic blood pressure improved within two hours in both groups. Systolic pulmonary arterial pressure and tricuspid regurgitation improved to a greater extent in the TT group at 24 h, and at 12 months (P < 0.001), as compared to those in the AT group. At one week, and 12 months, clot burden decreased more in AT group, as compared to that in AT group (P < 0.001). There was no death due to bleeding in both groups. Recurrent PE were similar in both groups (2.5% in TT vs. 1.8% in AT). The rates of minor hemorrhages were 6.3% in TT group and 1.8% in AT group (P < 0.05). Conclusion In submassive PE patient who has low risk of bleeding, thrombolysis plus anticoagulation can lead to greater improvement of right ventricular dysfunction and clot burden reduction as compared to anticoagulation therapy alone.     

Conditioned media from (pre)adipocytes stimulate fibrinogen and PAI-1 production by HepG2 hepatoma cells

Background:

Obesity is associated with a prothrombotic state, which may contribute to the increased risk of thrombotic events.

Objective:

To assess the effects of (pre)adipocyte-derived adipokines on fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) production by hepatocytes.

Methods:

HepG2 hepatocytes were incubated with conditioned media (CM) derived from preadipocytes and adipocytes, which had been untreated or prestimulated with tumor necrosis factor (TNF)-α, interleukin (IL)-1β or IL-6. After 24 h, supernatants and cell lysates were harvested for measurement of fibrinogen, PAI-1 and TF.

Results:

(Pre)adipocyte CM significantly enhanced the production of PAI-1 by HepG2 cells 2.5- to 4.4-fold. CM from cytokine-stimulated (pre)adipocytes significantly induced fibrinogen secretion 1.5- to 4.2-fold. TF production was not affected by the CM. After specific depletion of TNF-α, IL-1β or IL-6 from the CM, IL-6 was shown to be the most prominent stimulus of fibrinogen secretion and IL-1β of PAI-1 secretion. In addition, fibrinogen, PAI-1 and tissue factor production was evaluated by direct stimulation of HepG2 cells with TNF-α, IL-1β or IL-6. IL-6 enhanced fibrinogen synthesis 4.3-fold (P<0.01), whereas IL-1β induced PAI-1 production 5.0-fold (P<0.01). Gene expression analyses showed that TNF-α and IL-1β stimulate the adipocyte expression of TNF-α, IL-1β and IL-6. Cytokine stimulation of adipocytes may thus have induced an inflammatory response, which may have stimulated fibrinogen and PAI-1 production by HepG2 cells more potently.

Conclusions:

SGBS (pre)adipocytes release cytokines that increase the production of fibrinogen and PAI-1 by HepG2 cells. IL-6 and IL-1β produced by (pre)adipocytes were the strongest inducers of fibrinogen and PAI-1 secretion, respectively.     

Cytokeratin-based CTC counting unrelated to clinical follow up

Background

Circulating tumor cells (CTCs) have been reported to be a relevant prognostic biomarker in metastatic patients. However, their clinical use and impact is still under debate. We have thus comparatively and kinetically assessed two CTC detection methods according to the patient’s clinical follow up.

Methods

CTC counting and characterization were repeatedly performed during follow up in a patient with metastatic undifferentiated non-small cell lung cancer by using cytokeratin (CK)-dependent immunomagnetic separation (Miltenyi) and CK-independent, size-based isolation [isolation by size of tumor cells (ISET)] (Rarecells).

Results

Comparison between the two methods showed a parallel increase of CTC detected by ISET and worsening of the clinical status, while CK-dependent CTC numbers were decreasing, misleadingly suggesting a response to treatment. ISET results were in agreement with the clinical follow up showing Circulating tumor microemboli (CTM) and CTC expressing a mesenchymal marker with absence of epithelial markers.

Conclusions

This case report study shows the interest of a comparative and kinetic analysis of different methods for CTCs detection combined with their evaluation according to the clinical follow up. Our results should open up an area for future research and validation in larger clinical cohorts.KEYWORDS : Circulating tumor cells (CTCs), circulating tumor microemboli (CTM), lung cancer, immunomagnetic separation, isolation by size of tumor cells (ISET)     

Monocyte Angiotensin Converting Enzyme Expression May Be Associated with Atherosclerosis Rather than Arteriosclerosis in Hemodialysis Patients

Summary

Background and objectives

Circulating monocytes can be divided into functionally distinct subpopulations according to their surface expression of CD14 and CD16. Monocytes with high-level expression of both antigens (CD14⁺⁺CD16⁺, Mo2 cells) are associated with cardiovascular morbidity and mortality in hemodialysis patients. These cells express angiotensin converting enzyme (ACE) on their surface. They are involved in the association of chronic inflammation and cardiovascular disease in kidney patients. Cardiovascular morbidity results from atherosclerosis (plaque-forming, vessel occluding disease) and arteriosclerosis (loss of arterial dampening function). It is unknown whether ACE-expressing proinflammatory monocytes are related to atherosclerosis, arteriosclerosis, or both.

Design, setting, participants, & measurements

During baseline examination for a prospective study on monocyte ACE expression and mortality, 60 chronic hemodialysis patients of an academic outpatient center were screened for atherosclerosis by carotid artery ultrasound, for arteriosclerosis by pulse pressure measurement, and for ACE expression on Mo2 cells by flow cytometry.

Results

ACE expression on Mo2 monocytes was significantly higher in patients with severe compared with those with little or no carotid atherosclerosis. Mo2 ACE correlated with a score to semiquantify atherosclerosis and remained a significant predictor of carotid plaques in multivariate analysis including the other univariately associated variables of age, hemoglobin A1c, and albumin. Mo2 ACE was not related to pulse pressure.

Conclusions

ACE expression on Mo2, although being a known predictor of mortality and cardiovascular disease in end-stage renal disease patients, may act via enhancement of atherosclerosis rather than arteriosclerosis.