Tissue factor pathway inhibitor and other endothelium-dependent hemostatic factors in elderly individuals with normal or impaired glucose tolerance and type 2 diabetes

Long Non-Coding RNAs in Venous Thromboembolism: Where Do We Stand?

Venous thromboembolism (VTE), a common condition in Western countries, is a cardiovascular disorder that arises due to haemostatic irregularities, which lead to thrombus generation inside veins. Even with successful treatment, the resulting disease spectrum of complications considerably affects the patient's quality of life, potentially leading to death. Cumulative data indicate that long non-coding RNAs (lncRNAs) may have a role in VTE pathogenesis. However, the clinical usefulness of these RNAs as biomarkers and potential therapeutic targets for VTE management is yet unclear. Thus, this article reviewed the emerging evidence on lncRNAs associated with VTE and with the activity of the coagulation system, which has a central role in disease pathogenesis. Until now, ten lncRNAs have been implicated in VTE pathogenesis, among which MALAT1 is the one with more evidence. Meanwhile, five lncRNAs have been reported to affect the expression of TFPI2, an important anticoagulant protein, but none with a described role in VTE development. More investigation in this field is needed as lncRNAs may help dissect VTE pathways, aiding in disease prediction, prevention and treatment.

Thromboinflammatory Processes at the Nexus of Metabolic Dysfunction and Prostate Cancer: The Emerging Role of Periprostatic Adipose Tissue

Simple Summary

As overweight and obesity increase among the population worldwide, a parallel increase in the number of individuals diagnosed with prostate cancer was observed. There appears to be a relationship between both diseases where the increase in the mass of fat tissue can lead to inflammation. Such a state of inflammation could produce many factors that increase the aggressiveness of prostate cancer, especially if this inflammation occurred in the fat stores adjacent to the prostate. Another important observation that links obesity, fat tissue inflammation, and prostate cancer is the increased production of blood clotting factors. In this article, we attempt to explain the role of these latter factors in the effect of increased body weight on the progression of prostate cancer and propose new ways of treatment that act by affecting how these clotting factors work.

Abstract

The increased global prevalence of metabolic disorders including obesity, insulin resistance, metabolic syndrome and diabetes is mirrored by an increased incidence of prostate cancer (PCa). Ample evidence suggests that these metabolic disorders, being characterized by adipose tissue (AT) expansion and inflammation, not only present as risk factors for the development of PCa, but also drive its increased aggressiveness, enhanced progression, and metastasis. Despite the emerging molecular mechanisms linking AT dysfunction to the various hallmarks of PCa, thromboinflammatory processes implicated in the crosstalk between these diseases have not been thoroughly investigated. This is of particular importance as both diseases present states of hypercoagulability. Accumulating evidence implicates tissue factor, thrombin, and active factor X as well as other players of the coagulation cascade in the pathophysiological processes driving cancer development and progression. In this regard, it becomes pivotal to elucidate the thromboinflammatory processes occurring in the periprostatic adipose tissue (PPAT), a fundamental microenvironmental niche of the prostate. Here, we highlight key findings linking thromboinflammation and the pleiotropic effects of coagulation factors and their inhibitors in metabolic diseases, PCa, and their crosstalk. We also propose several novel therapeutic targets and therapeutic interventions possibly modulating the interaction between these pathological states.

Hypofibrinolysis in type 2 diabetes and its clinical implications: from mechanisms to pharmacological modulation

A prothrombotic state is a typical feature of type 2 diabetes mellitus (T2DM). Apart from increased platelet reactivity, endothelial dysfunction, hyperfibrinogenemia, and hypofibrinolysis are observed in T2DM. A variety of poorly elucidated mechanisms behind impaired fibrinolysis in this disease have been reported, indicating complex associations between platelet activation, fibrin formation and clot structure, and fibrinolysis inhibitors, in particular, elevated plasminogen antigen inhibitor-1 levels which are closely associated with obesity. Abnormal fibrin clot structure is of paramount importance for relative resistance to plasmin-mediated lysis in T2DM. Enhanced thrombin generation, a proinflammatory state, increased release of neutrophil extracellular traps, elevated complement C3, along with posttranslational modifications of fibrinogen and plasminogen have been regarded to contribute to altered clot structure and impaired fibrinolysis in T2DM. Antidiabetic agents such as metformin and insulin, as well as antithrombotic agents, including anticoagulants, have been reported to improve fibrin properties and accelerate fibrinolysis in T2DM. Notably, recent evidence shows that hypofibrinolysis, assessed in plasma-based assays, has a predictive value in terms of cardiovascular events and cardiovascular mortality in T2DM patients. This review presents the current data on the mechanisms underlying arterial and venous thrombotic complications in T2DM patients, with an emphasis on hypofibrinolysis and its impact on clinical outcomes. We also discuss potential modulators of fibrinolysis in the search for optimal therapy in diabetic patients.

Evening chronotype is associated with elevated biomarkers of cardiometabolic risk in the EpiHealth cohort: a cross-sectional study

STUDY OBJECTIVES

Individuals with evening chronotype have a higher risk of cardiovascular and metabolic disorders, although the underlying mechanisms are not well understood. In a population-based cohort, we aimed to investigate the association between chronotype and 242 circulating proteins from three panels of established or candidate biomarkers of cardiometabolic processes.

METHODS

In 2,471 participants (49.7% men, mean age 61.2±8.4 SD years) from the EpiHealth cohort, circulating proteins were analyzed with a multiplex proximity extension technique. Participants self-reported their chronotype on a five-level scale from extreme morning to extreme evening chronotype. With the intermediate chronotype set as the reference, each protein was added as the dependent variable in a series of linear regression models adjusted for confounders. Next, the chronotype coefficients were jointly tested and the resulting p-values adjusted for multiple testing using false discovery rate (5%). For the associations identified, we then analyzed the marginal effect of each chronotype category.

RESULTS

We identified 17 proteins associated with chronotype. Evening chronotype was positively associated with proteins previously linked to insulin resistance and cardiovascular risk, namely retinoic acid receptor protein 2, fatty acid-binding protein adipocyte, tissue-type plasminogen activator, and plasminogen activator inhibitor 1 (PAI-1). Additionally, PAI-1 was inversely associated with the extreme morning chronotype.

CONCLUSIONS

In this population-based study, proteins previously related with cardiometabolic risk were elevated in the evening chronotypes. These results may guide future research in the relation between chronotype and cardiometabolic disorders.

Thrombin generation in cardiovascular disease and mortality - results from the Gutenberg Health Study

Thrombin generation may be a potential tool to improve risk stratification for cardiovascular diseases. This study aims to explore the relation between thrombin generation and cardiovascular risk factors, cardiovascular diseases, and total mortality. For this study, N=5000 subjects from the population-based Gutenberg Health Study were analysed in a highly standardized setting. Thrombin generation was assessed by the Calibrated Automated Thrombogram method at 1 and 5 pM tissue factors trigger in platelet poor plasma. Lag time, endogenous thrombin potential, and peak height were derived from the thrombin generation curve. Sex-specific multivariable linear regression analysis adjusted for age, cardiovascular risk factors, cardiovascular diseases and therapy, was used to assess clinical determinants of thrombin generation. Cox regression models adjusted for age, sex, cardiovascular risk factors and vitamin K antagonists investigated the association between thrombin generation parameters and total mortality. Lag time was positively associated with obesity and dyslipidaemia for both sexes (p<0.0001). Obesity was also positively associated with endogenous thrombin potential in both sexes (p<0.0001) and peak height in males (1 pM tissue factor, p=0.0048) and females (p<0.0001). Cox regression models showed an increased mortality in individuals with lag time (1 pM tissue factor, hazard ratio=1.46, [95% CI: 1.07; 2.00], p=0.018) and endogenous thrombin potential (5 pM tissue factor, hazard ratio = 1.50, [1.06; 2.13], p=0.023) above the 95th percentile of the reference group, independent of the cardiovascular risk profile. This large-scale study demonstrates traditional cardiovascular risk factors, particularly obesity, as relevant determinants of thrombin generation. Lag time and endogenous thrombin potential were found as potentially relevant predictors of increased total mortality, which deserves further investigation.

Heparanase in the Coagulation System

The hemostatic cascade is initiated by the transmembrane coagulation protein - tissue factor (TF) and eventuates in fibrin formation. Heparanase protein was demonstrated to directly enhance TF activity resulting in increased activation of the coagulation system. In addition, heparanase was found to increase hemostatic system activation via two other mechanisms: up-regulating TF expression in endothelial cells and releasing the protein tissue factor pathway inhibitor (TFPI) from the cell surface. Peptides derived from TFPI-2, a protein similar to TFPI, were shown to inhibit the TF/heparanase complex as well as attenuate sepsis and tumor growth. Increased heparanase procoagulant activity was observed in several clinical settings, including women using oral contraceptives, women at delivery, patients following orthopedic surgery and patients with diabetic foot, shift work female nurses, patients with lung cancer, retinal vein thrombosis and prosthetic heart valve thrombosis. Remarkably, the heparanase profile was significantly different across the tested groups. Inhibition of TF / heparanase interaction may represent a new target for attenuating coagulation, cancer and inflammation.

Glycative and oxidative stress are associated with altered thrombus composition in diabetic patients with ST-elevation myocardial infarction

BACKGROUND

The role of type 2 diabetes (T2DM) on composition of thrombus has not been fully characterized in patients with ST-elevation myocardial infarction (STEMI).

AIMS

To elucidate the differences between diabetic and non-diabetic patients with STEMI in relation to the composition of coronary thrombus, and the potential association of these differences with glycated haemoglobin levels and markers of oxidative stress.

METHODS

Intracoronary thrombi from consecutive thrombus aspiration procedures in STEMI patients, 25 diabetic and 28 non-diabetic, were analyzed by immunofluorescence with confocal microscopy. Plasma biomarkers (P-selectin, vWF, PAI-1, t-PA, D-dimer, TF pathway markers, plasmin and CD34⁺) were measured in peripheral blood, and the oxidative capacity of plasma as indirect measure of oxidative stress was measured in parallel.

RESULTS

Patients with T2DM had higher levels of fibrin (P=0.03), P-selectin (P=0.0001), PAI-1 (P=0.03) and vWF (P=0.006) in the thrombus and higher plasma TF activity (P=0.01) compared to non-diabetics. TF activity and plasmin correlated with HbA₁C levels (R²=0.71, P=0.0001; R²=0.46, P=0.04, respectively) and TF was inversely correlated with TFPI (R²=-0.44, P=0.008) and tPA (R²=-0.48, P=0.003). Diabetic patients showed a higher oxidative response of plasma (26.47±6.88% vs 22.06±6.96% of oxidized lipids, P=0.04) (measured by H-NMR spectroscopy) that was associated to increased fibrin content into thrombus (R²=0.76, P=0.01).

CONCLUSION

Diabetic patients with STEMI display an increased thrombogenicity that results in a different thrombus composition respect to non-diabetic patients with STEMI. The increased thrombogenicity present in T2DM is related to higher glycoxidative stress, as quantified by HbA₁C levels and oxidative response in plasma.

The metabolic syndrome: an emerging risk state for cardiovascular disease

The common clustering of glucose intolerance, insulin resistance, abdominal adiposity, elevated blood pressure, and low HDL cholesterol is referred to as metabolic syndrome. Individuals with this syndrome have an increased risk of developing cardiovascular disease (CVD). The World Health Organisation and the National Cholesterol Education Programme’s Adult Treatment Panel III (NCEP-ATP III) have outlined specific diagnostic criteria for the diagnosis of the metabolic syndrome to help in the Identification of this syndrome in clinical practice. While the WHO criteria were specifically developed for use in research, the NCEP criteria are useful in clinical diagnosis of the metabolic syndrome. The metabolic syndrome is amenable to lifestyle modifications such as increased physical activity, weight loss, and possibly intake of low-glycemic foods. Drug therapy may be used to treat individual components of the syndrome such as elevated blood pressure and dyslipidemia. To control elevated glucose levels (when there is failure of lifestyle modification), medications such as metformin, thiazolidinedione derivatives and alpha glucosidase inhibitors may be used.

Central Versus Peripheral Pulmonary Embolism: Analysis of the Impact on the Physiological Parameters and Long-term Survival

BACKGROUND

Studies aimed at assessing whether the emboli lodged in the central pulmonary arteries carry a worse prognosis than more peripheral emboli have yielded controversial results.

AIMS

To explore the impact on survival and long-term prognosis of central pulmonary embolism.

PATIENTS AND METHODS

Consecutive patients diagnosed with acute symptomatic pulmonary embolism by means of computed tomography (CT) angiography were evaluated at episode index and traced through the computed system of clinical recording and following-up. Central pulmonary embolism was diagnosed when thrombi were seen in the trunk or in the main pulmonary arteries and peripheral pulmonary embolism when segmental or subsegmental arteries were affected.

RESULTS

A total of 530 consecutive patients diagnosed with pulmonary embolism were evaluated; 255 patients had central pulmonary embolism and 275 patients had segmental or subsegmental pulmonary embolism. Patients with central pulmonary embolism were older, had higher plasma levels of N-terminal of the prohormone brain natriuretic peptide (NT-ProBNP), troponin I, D-dimer, alveolar-arterial gradient, and shock index (P < .001 for each one). Patients with central pulmonary embolism had an all-cause mortality of 40% while patients with segmental or subsegmental pulmonary embolism (PE) had an overall mortality of 27% and odds ratio of 1.81 [confidence interval (CI) 95% 1.16-1.9]. Survival was lower in patients with central PE than in patients with segmental or subsegmental pulmonary embolism, even after avoiding confounders (P = .018).

CONCLUSIONS

Apart from a greater impact on hemodynamics, gas exchange, and right ventricular dysfunction, central pulmonary embolism associates a shorter survival and an increased long-term mortality.

Plasminogen activator inhibitor-1 and type 2 diabetes: a systematic review and meta-analysis of observational studies

An emerging body of evidence has implicated plasminogen activator inhibitor-1 (PAI-1) in the development of type 2 diabetes (T2D), though findings have not always been consistent. We systematically reviewed epidemiological studies examining the association of PAI-1 with T2D. EMBASE, PubMed, Web of Science, and the Cochrane Library were searched to identify studies for inclusion. Fifty-two studies (44 cross-sectional with 47 unique analytical comparisons and 8 prospective) were included. In pooled random-effects analyses of prospective studies, a comparison of the top third vs. bottom third of baseline PAI-1 values generated a RR of T2D of 1.67 (95% CI 1.28–2.18) with moderate heterogeneity (I² = 38%). Additionally, of 47 cross-sectional comparisons, 34(72%) reported significantly elevated PAI-1 among diabetes cases versus controls, 2(4%) reported significantly elevated PAI-1 among controls, and 11(24%) reported null effects. Results from pooled analyses of prospective studies did not differ substantially by study design, length of follow-up, adjustment for various putative confounding factors, or study quality, and were robust to sensitivity analyses. Findings from this systematic review of the available epidemiological literature support a link between PAI-1 and T2D, independent of established diabetes risk factors. Given the moderate size of the association and heterogeneity across studies, future prospective studies are warranted.

Heparanase and coagulation-new insights

Heparanase, a β-D-endoglucuronidase abundant in platelets that was discovered 30 years ago, is an enzyme that cleaves heparan sulfate side chains on the cell surface and in the extracellular matrix. It was later recognized as being a pro-inflammatory and pro-metastatic protein. We had earlier demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. We had shown that heparanase up-regulated the expression of the blood coagulation initiator tissue factor (TF) and interacted with the tissue factor pathway inhibitor (TFPI) on the cell surface membrane of endothelial and tumor cells, leading to dissociation of TFPI and resulting in increased cell surface coagulation activity. Moreover, we have demonstrated that heparanase directly enhanced TF activity which led to increased factor Xa production and subsequent activation of the coagulation system. Recently, heparanase inhibitory peptides derived of TFPI-2 were demonstrated by us to inhibit heparanase procoagulant activity and attenuate sepsis in mouse models.

Zucker Diabetic Fatty rats exhibit hypercoagulability and accelerated thrombus formation in the Arterio-Venous shunt model of thrombosis

INTRODUCTION

Diabetes is a significant risk factor for thrombosis. The present study aimed at assessing coagulability, platelet reactivity, and thrombogenicity of the diabetic female Zucker Diabetic Fatty (ZDF) rat model and its relevance in studying antithrombotic mechanisms.

MATERIALS AND METHODS

The basal coagulant state in ZDF rats was evaluated by clotting times, thromboelastography, and thrombin generation assay. A 14-day treatment with dapagliflozin in ZDF rats was pursued to investigate if glycemic control can improve coagulability. Thrombus formation in the Arterio-Venous (A-V) shunt model and the FeCl3-induced arterial thrombosis model was studied, with the antithrombotic effect of apixaban in the former model further investigated.

RESULTS

ZDF rats exhibited significantly shortened clotting times, enhanced thrombin generation, and decreased fibrinolysis at baseline. Effective glycemic control achieved with dapagliflozin did not improve any of these parameters. ZDF rats displayed accelerated thrombus formation and were amenable to apixaban treatment in the A-V shunt model albeit with less sensitivity than normal rats. ZDF rats exhibited less platelet aggregation in response to ADP, collagen and PAR-4, and attenuated thrombotic response in the FeCl3 model.

CONCLUSIONS

ZDF rats are at a chronic hypercoagulable and hypofibrinolytic state yet with compromised platelet reactivity. They display accelerated and attenuated thrombosis in the A-V shunt and FeCl3 model of thrombosis, respectively. Results shed new light on the pathophysiology of the ZDF rat model and illustrate its potential value in translational research on anticoagulant agents in diabetics. Caution needs to be exerted in utilizing this model in assessing antiplatelet mechanisms in diabetes-associated atherothrombosis.

Heparanase-A Link between Coagulation, Angiogenesis, and Cancer

Heparanase that was cloned from and is abundant in the placenta is implicated in cell invasion, tumor metastasis, and angiogenesis. Recently we have demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. Heparanase was shown to up-regulate tissue factor (TF) expression and interact with tissue factor pathway inhibitor (TFPI) on the cell surface, leading to dissociation of TFPI from the cell membrane of endothelial and tumor cells, resulting in increased cell surface coagulation activity. More recently, we have shown that heparanase directly enhances TF activity, resulting in increased factor Xa production and activation of the coagulation system. Data indicate increased levels and possible involvement of heparanase in vascular complications in pregnancy. Taking into account the prometastatic and proangiogenic functions of heparanase, overexpression in human malignancies, and abundance in platelets and placenta, its involvement in the coagulation machinery is an intriguing novel arena for further research.

Tissue Factor, Tissue Factor Pathway Inhibitor and Factor VII Activity in Cardiovascular Complicated Type 2 Diabetes Mellitus

OBJECTIVES

Tissue factor (TF) is the main initiator of the extrinsic coagulation pathway through factor VII (FVII) activation, which is physiologically inhibited by tissue factor pathway inhibitor (TFPI). Alteration of this pathway has been described in Type 2 diabetes mellitus (T2DM). The aim of this study is to assess TF and TFPI plasma levels and FVII coagulant activity (FVIIa) in T2DM in relation to cardiothrombotic disease and their correlation to metabolic and clinical behavior of the patients.

METHODS

The study was conducted on 80 T2DM patients divided to accordingly; groupI: 40 patients without a history or clinically detected heart disease, and groupII: 40 patients with a history of myocardial infarction compared to 30 controls. The patients were recruited from Ain Shams University diabetes clinic from September 2007 to February 2009 after informed consent was obtained. Peripheral blood samples were taken for measurement of plasma TF and TFPI levels using ELISA technique and quantitative FVIIa using FVII deficient plasma.

RESULTS

Plasma levels of TF, TFPI and FVIIa were significantly higher in T2DM patients compared to the controls (p<0.001). TF (236.50±79.23)and TFPI (242.33±85.84)were significantly higher in group II, compared to group I (150.33±81.16), (152.8± 82.46), (p<0.001). TF and TFPI were significantly correlated to body mass index and glycemic control. Also, TF and TFPI were significantly higher in hypertensives (p=0.001) and dyslipidemics (p=0.006) but not in smokers (p=0.64), (p=0.11) respectively.

CONCLUSION

There was a correlation between high TF, TFPI plasma levels, FVIIa activity and cardiothrombotic complications in T2DM especially in the presence of high risk factors such as poor glycemic control, dyslipidemia and obesity. Future target therapy against TF may be beneficial for T2DM patients.

Impaired glucose metabolism and type 2 diabetes are associated with hypercoagulability: potential role of central adiposity and low-grade inflammation--the Hoorn Study

INTRODUCTION

Type 2 diabetes (DM2) is associated with greater risk for cardiovascular disease (CVD), which may, at least partially, be explained by prothrombotic alterations. We therefore investigated; first, the extent to which individuals with impaired glucose metabolism (IGM) and/or DM2 had greater levels of thrombin generation than those with normal glucose metabolism (NGM); and second, whether any differences were independent of other cardiovascular risk factors, such as smoking, hypertension, dyslipidaemia, (micro)albuminuria, glycemic control and (central) adiposity, and/or were potentially 'mediated' by low-grade inflammation (high-sensitivity C-reactive protein (hsCRP)).

MATERIALS AND METHODS

We studied 744 individuals from the Hoorn Study (275 NGM, 176 IGM and 293 DM2, mean age 68.6 ± 7.1 years). Thrombin generation in platelet-poor plasma was measured using the Calibrated Automated Thrombogram and three parameters were derived: lag time, peak height and endogenous thrombin potential (ETP). Data were analyzed with multiple linear regression analyses.

RESULTS

After adjustment for age, sex, prior CVD and smoking status, individuals with IGM or DM2 had a longer lag time [ß = 0.14 min (95% CI: 0.02; 0.26)], higher peak height [ß = 7.29 nM (-1.33; 15.91)] and ETP [ß = 35.65 nM*min (0.97; 70.34)] than those with NGM. These differences were attenuated to ß = 0.06 min (-0.07; 0.19), 3.82 nM (-5.46; 13.10) and 16.34 nM*min (-20.92; 53.59), respectively, when further adjusted for waist circumference and hsCRP.

CONCLUSION

Individuals with IGM or DM2 had up to 4% higher thrombin generation compared with NGM, which may be explained, to a great extent, by the greater levels of central adiposity and related low-grade inflammation characterizing these individuals.

Mechanisms of vascular complications in prediabetes

Although the state of prediabetes is defined by its role as a diabetes risk factor, it also carries a significant risk of cardiovascular disease, independent of progression to diabetes. Typical diabetic microvascular complications also occur, albeit at low rates, in prediabetes. There is evidence that both glucose-related and glucose-independent mechanisms contribute to these vascular complications. Effective preventive strategies will likely require control of glycemia, as well as other metabolic risk factors. This article reviews some of the proposed mechanisms for the vascular complications of the prediabetic state.

Body composition as determinant of thrombin generation in plasma: the Hoorn study

OBJECTIVE

The association between obesity and cardiovascular disease and venous thromboembolism might, at least partially, be explained by a hypercoagulable state. The extent to which body fat mass and its distribution contribute to a hypercoagulable state is unknown. In this study, we investigated the association between body composition and thrombin generation and evaluated the potential mediating role of low-grade inflammation.

METHODS AND RESULTS

We studied 586 individuals from the Hoorn Study (mean age, 69.7 ± 6.5 years, 298 women) in whom body composition was assessed by whole body dual-energy absorptiometry. Thrombin generation was measured using the calibrated automated thrombogram. Multiple regression analyses showed a positive association between total body fat and thrombin generation in women but not in men. In addition, detailed analyses of regional body composition showed that central but not peripheral fat mass was associated with greater thrombin generation and that there was a trend toward an inverse association with peripheral lean mass. The reported positive associations were partially attenuated by low-grade inflammation, however.

CONCLUSIONS

Body fat mass, in particular a central pattern of fat distribution, is associated with higher levels of thrombin generation in elderly women but not in men. This association may partially be explained by adiposity-related low-grade inflammation, but this hypothesis needs to be further investigated in mechanistic/prospective studies.

Heparanase procoagulant effects and inhibition by heparins

Heparanase is an endo-beta-D-glucuronidase capable of cleaving heparan sulfate (HS) side chains of heparan sulfate proteoglycans (HSPG) on cell surfaces and the extracellular matrix, activity that is strongly implicated in tumor metastasis and angiogenesis. Evidence was provided that heparanase over-expression in cancer cells results in a marked increase in tissue factor (TF) levels. Likewise, TF was induced by exogenous addition of recombinant heparanase to tumor cells and primary endothelial cells, induction that was mediated by p38 phosphorylation and correlated with enhanced procoagulant activity. TF induction was further confirmed in heparanase over-expressing transgenic mice and correlated with heparanase expression levels in leukemia patients. Heparanase was also found to be involved in the regulation of tissue factor pathway inhibitor (TFPI). A physical interaction between heparanase and TFPI was demonstrated, suggesting a mechanism by which secreted heparanase interacts with TFPI on the cell surface, leading to dissociation of TFPI from the cell membrane and increased coagulation activity, thus further supporting the local pro-thrombotic function of heparanase. Data indicate a possible involvement of heparanase in early miscarriages and point to a regulatory effect on TFPI and TFPI-2 in trophoblasts. As heparins are strong inhibitor of heparanase, in view of the effect of heparanase on TF, the role of heparins anticoagulant-activity may potentially be expanded. Taking into account the pro-metastatic and pro-angiogenic functions of heparanase, its over-expression in human malignancies and abundance in platelets, its involvement in the coagulation machinery is an intriguing novel arena for further research.

Circulating vascular endothelial growth factor in the normo- and/or microalbuminuric patients with type 2 diabetes mellitus

Relationship between serum vascular endothelial growth factor (VEGF) level and parameters of endothelial injury and/or dysfunction in patients with diabetes mellitus type 2 with or without microalbuminuria was investigated. Eighty-four diabetic patients were divided in two subgroups (42 each): normoalbuminuric (NAU) and microalbuminuric (MAU). Forty-two blood donors were in control group. Serum VEGF and plasma von Willebrand factor, soluble thrombomodulin, plasminogen activator inhibitor 1, thrombin-activatable fibrinolysis inhibitor (TAFI) and tissue plasminogen activator (t-PA) were measured using enzyme-linked immunosorbent assay in all subjects. VEGF was significantly higher in NAU compared to controls. The difference between MAU and controls was not statistically significant, but there was a trend toward significance. Only TAFI correlated with VEGF in MAU. An observed significant increase of serum VEGF level already in NAU suggests that serum VEGF could be a sensitive predictor of endothelial dysfunction in type 2 diabetes.

[The role of platelets in atherosclerosis, diabetes mellitus, and chronic kidney disease. An attempt at explaining the TREAT study results]

Erythropoiesis-stimulating agents (ESA) are used to treat renal anemia. The TREAT study (Trial to Reduce Cardiovascular Events with Aranesp Ther- apy) of diabetic patients with chronic kidney disease (CKD) found that the risk of stroke was significantly higher than in the control arm. This raises the question as to what causes this phenomenon. Platelets may play a crucial role in this context. Atherogenesis involves complex interactions between platelets and monocytes (platelet-monocyte crosstalk) and with endothelial cells. Platelets are activated in cases of diabetes mellitus, especially. During atherogenesis, partial functions of platelets other than those inhibited by aspirin, as a cyclooxygenase inhibitor, or by adenosine diphosphate receptor P2Y(12)antagonists, such as thienopyridines, are of relevance. During platelet-monocyte crosstalk, specifically, an important role is played by adhesion receptors such as selectins and integrins. In addition, ESA cause platelet activation by direct and indirect mechanisms. Antagonistic thereto is a renal bleeding tendency in cases of severe CKD, due to platelet dysfunction, which can be remedied with appropriate renal replacement therapy and administration of ESA in order to reach a hemoglobin (Hb) level of 10 g/dl. However, if the Hb level exceeds 10 g/dl, the even stronger platelet activation caused by ESA, combined with the activation caused by diabetes, leads to a prothrombotic state, which in patients with severe atherosclerosis can result in acute atherothrombotic complications, in the genesis of which platelets play a key role. This would be one hypothesis for explaining the increased incidence of strokes in the TREAT study.

Identification of an unusual pattern of global gene expression in group B Streptococcus grown in human blood

Because passage of the bacterium to blood is a crucial step in the pathogenesis of many group B Streptococcus (GBS) invasive infections, we recently conducted a whole-genome transcriptome analysis during GBS incubation ex vivo with human blood. In the current work, we sought to analyze in detail the difference in GBS gene expression that occurred in one blood sample (donor A) relative to other blood samples. We incubated GBS strain NEM316 with fresh heparinized human blood obtained from healthy volunteers, and analyzed GBS genome expression and cytokine production. Principal component analysis identified extensive clustering of the transcriptome data among all samples at time 0. In striking contrast, the whole bacterial gene expression in the donor A blood sample was significantly different from the gene expression in all other blood samples studied, both after 30 and 90 min of incubation. More genes were up-regulated in donor A blood relative to the other samples, at 30 min and 90 min. Furthermore, there was significant variation in transcript levels between donor A blood and other blood samples. Notably, genes with the highest transcript levels in donor A blood were those involved in carbohydrate metabolism. We also discovered an unusual production of proinflammatory and immunomodulatory cytokines: MIF, tPAI-1 and IL-1β were produced at higher levels in donor A blood relative to the other blood samples, whereas GM-CSF, TNF-α, IFN-γ, IL-7 and IL-10 remained at lower levels in donor A blood. Potential reasons for our observations are that the immune response of donor A significantly influenced the bacterial transcriptome, or both GBS gene expression and immune response were influenced by the metabolic status of donor A.

Heparanase coagulation and cancer progression

Heparanase is an endo-beta-D-glucuronidase capable of cleaving heparan sulphate (HS) side chains of heparan sulphate proteoglycans on cell surfaces and the extracellular matrix; activity that is strongly implicated in tumour metastasis and angiogenesis. It has been shown that heparanase overexpression in human leukaemia, glioma and breast carcinoma cells results in a marked increase in tissue factor (TF) levels. In addition, TF was induced by exogenous addition of recombinant heparanase to tumour cells and primary endothelial cells; induction that was mediated by p38 phosphorylation and correlated with enhanced procoagulant activity. TF induction was further confirmed in transgenic mice overexpressing heparanase, and correlated with heparanase expression levels in leukaemia patients. Heparanase was also found to be involved in the regulation of tissue factor pathway inhibitor (TFPI). It has been shown that heparanase overexpression or exogenous addition induces a two- to three-fold increase in TFPI expression. Similarly, heparanase stimulated accumulation of TFPI in the cell culture medium. However, extracellular accumulation exceeded the observed increase in TFPI at the protein level, and appeared to be independent of HS and heparanase enzymatic activity. Instead, a physical interaction between heparanase and TFPI was demonstrated, suggesting a mechanism by which secreted heparanase interacts with TFPI on the cell surface, leading to dissociation of TFPI from the cell membrane and increased coagulation activity, thus further supporting the local prothrombotic function of heparanase. As heparins are strong inhibitors of heparanase, in view of the effect of heparanase on the TF/TFPI pathway, the role of anticoagulant activity of heparin may potentially be expanded. Taking into account the prometastatic and pro-angiogenic functions of heparanase, its overexpression in human malignancies and abundance in platelets, its involvement in the coagulation machinery is an intriguing novel arena for further research.

Comparison of skin microvascular reactivity with hemostatic markers of endothelial dysfunction and damage in type 2 diabetes

Aim:

Patients with non-insulin-dependent diabetes mellitus (NIDDM) are at increased cardiovascular risk due to an accelerated atherosclerotic process. The present study aimed to compare skin microvascular function, pulse wave velocity (PWV), and a variety of hemostatic markers of endothelium injury [von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA), tissue factor pathway inhibitor (TFPI), and the soluble form of thrombomodulin (s-TM)] in patients with NIDDM.

Methods:

54 patients with NIDDM and 38 sex- and age-matched controls were studied. 27 diabetics had no overt micro- and/or macrovascular complications, while the remainder had either or both. The forearm skin blood flow was assessed by laser-Doppler imaging, which allowed the measurement of the response to iontophoretically applied acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation), as well as the reactive hyperemia triggered by the transient occlusion of the circulation.

Results:

Both endothelial and non-endothelial reactivity were significantly blunted in diabetics, regardless of the presence or the absence of vascular complications. Plasma vWF, TFPI and s-TM levels were significantly increased compared with controls only in patients exhibiting vascular complications. Concentrations of t-PA and PAI-1 were significantly increased in the two groups of diabetics versus controls.

Conclusion:

In NIDDM, both endothelium-dependent and -independent microvascular skin reactivity are impaired, whether or not underlying vascular complications exist. It also appears that microvascular endothelial dysfunction is not necessarily associated in NIDDM with increased circulating levels of hemostatic markers of endothelial damage known to reflect a hypercoagulable state.

Impaired glucose tolerance and endothelial damage, as assessed by levels of von Willebrand factor and circulating endothelial cells, following acute myocardial infarction

BACKGROUND

Impaired glucose tolerance (IGT) following acute myocardial infarction (AMI) increases the incidence of major adverse cardiac events. We hypothesized that endothelial damage following AMI, as assessed by levels of von Willebrand factor (vWF) and circulating endothelial cells (CECs), would be more pronounced in patients with IGT compared to those with normal glucose tolerance (NGT).

METHODS

We studied non-diabetic patients with AMI (n=125; 107 (86%) male; mean age 59 years (SD 12.5)) who underwent oral glucose tolerance testing 3-5 days after admission. We measured vWF (enzyme-linked immunosorbent assay) and CECs (CD146 immunobead capture) in the fasting state and at 2 h post glucose load.

RESULTS

Base-line vWF and CEC levels were higher in IGT patients versus those with NGT and healthy controls (HC) (P<0.001). The acute increase in vWF and CECs in response to the glucose load was significantly higher in the IGT group compared to those with NGT and HC (P<0.01)-an increase on a par with that seen in newly diagnosed diabetics.

CONCLUSION

The degree of endothelial damage post AMI in patients with IGT is greater than NGT, and comparable to that seen in frank diabetes mellitus. Subjects with IGT therefore need to be as actively sought and managed.

The antioxidant alpha-lipoic acid improves endothelial dysfunction induced by acute hyperglycaemia during OGTT in impaired glucose tolerance

OBJECTIVE

Impaired glucose tolerance (IGT) is considered a transitional phase in the development of type 2 diabetes, and is also independently associated with the occurrence of cardiovascular disease. Endothelial dysfunction (ED) represents a very early step in the development of atherosclerosis. The aim of the present study was to examine ED in the fasting state and after a glucose challenge as well as after administration of an antioxidant agent.

PATIENTS AND METHODS

The study subjects included 42 IGT patients and 26 healthy individuals (control group). The IGT patients were randomly divided into two groups, 21 in each group (the alpha-lipoic acid group and the placebo group). In the alpha-lipoic acid group, 300 mg of alpha-lipoic acid was administrated before an oral glucose tolerance test (OGTT); in the placebo group, 250 ml of 0.9% sodium chloride was administrated before the OGTT. In addition, 250 ml of 0.9% sodium chloride was also administrated to the control subjects before the OGTT (control group), and then vascular function was examined in the fasting state and repeated 1 and 2 h after the glucose load. High-resolution ultrasound was used to measure flow-mediated endothelium-dependent arterial dilation (FMD) and glyceryltrinitrate (GTN)-induced endothelium-independent arterial dilation.

RESULTS

In the fasting state, and at 60 and 120 min, FMD in both the placebo and alpha-lipoic acid groups was significantly lower than in the controls (P < 0.01). In the control group, FMD tended to decrease at 60 min after glucose loading and returned to the baseline levels at 120 min (P > 0.05). In the placebo group, FMD decreased significantly at 60 min after glucose loading (P < 0.01) and increased markedly from 60 to 120 min (P < 0.01). The alpha-lipoic acid-treated patients showed FMD values intermediate between the control subjects and the IGT patients treated with placebo, at both 60 and 120 min, and the differences were significant (P < 0.01). In multiple regression analysis, FMD was significantly correlated to fasting blood glucose (FBG), low density lipoprotein cholesterol (LDL-C), lipoprotein (a) [Lp(a)], C-reactive protein (CRP), thiobarbituric acid reactive substances (TBARS) and age in IGT patients at baseline (P < 0.01). Spearman's analysis showed a significant negative correlation between FMD and plasma glucose levels, and between FMD and TBARS during the OGTT in IGT patients (placebo group) (P < 0.01). There was also a significant correlation between FMD and plasma glucose levels, and between FMD and TBARS during the OGTT in IGT patients treated with alpha-lipoic acid (P < 0.05), although the power of association decreased.

CONCLUSION

In subjects with IGT, FMD was impaired both in the fasting state and after a glucose challenge, probably through increased production of oxygen-derived free radicals. The ED observed after a glucose challenge is related to the extent of hyperglycaemia and TBARS, and an antioxidant agent can improve the impairment of endothelial function induced by acute hyperglycaemia.

Endothelial dysfunction in diabetes mellitus

Diabetes mellitus is associated with an increased risk of cardiovascular disease, even in the presence of intensive glycemic control. Substantial clinical and experimental evidence suggest that both diabetes and insulin resistance cause a combination of endothelial dysfunctions, which may diminish the anti-atherogenic role of the vascular endothelium. Both insulin resistance and endothelial dysfunction appear to precede the development of overt hyperglycemia in patients with type 2 diabetes. Therefore, in patients with diabetes or insulin resistance, endothelial dysfunction may be a critical early target for preventing atherosclerosis and cardiovascular disease. Microalbuminuria is now considered to be an atherosclerotic risk factor and predicts future cardiovascular disease risk in diabetic patients, in elderly patients, as well as in the general population. It has been implicated as an independent risk factor for cardiovascular disease and premature cardiovascular mortality for patients with type 1 and type 2 diabetes mellitus, as well as for patients with essential hypertension. A complete biochemical understanding of the mechanisms by which hyperglycemia causes vascular functional and structural changes associated with the diabetic milieu still eludes us. In recent years, the numerous biochemical and metabolic pathways postulated to have a causal role in the pathogenesis of diabetic vascular disease have been distilled into several unifying hypotheses. The role of chronic hyperglycemia in the development of diabetic microvascular complications and in neuropathy has been clearly established. However, the biochemical or cellular links between elevated blood glucose levels, and the vascular lesions remain incompletely understood. A number of trials have demonstrated that statins therapy as well as angiotensin converting enzyme inhibitors is associated with improvements in endothelial function in diabetes. Although antioxidants provide short-term improvement of endothelial function in humans, all studies of the effectiveness of preventive antioxidant therapy have been disappointing. Control of hyperglycemia thus remains the best way to improve endothelial function and to prevent atherosclerosis and other cardiovascular complications of diabetes. In the present review we provide the up to date details on this subject.

Adiponectin Mediates the Suppressive Effect of Rosiglitazone on Plasminogen Activator Inhibitor-1 Production

Objective— The purpose of this study was to examine the effects of PPAR-γ agonist rosiglitazone, relative to sulfonylureas, on circulating levels of adiponectin and the prothrombotic factor, plasminogen activator inhibitor (PAI)-1, in type 2 diabetic patients, and to investigate, in animal models, whether the antithrombotic action of rosiglitazone was mediated through adiponectin.

Methods and Results— Our clinical study (n=64) showed that after 24-week add-on therapy, the rosiglitazone group had a greater mean reduction in plasma PAI-1 levels (25%, versus 12% in sulfonylurea group, P =0.002). Stepwise multiple linear regression analysis identified the reduction in plasma fasting glucose and the rise in adiponectin levels to be independently associated with the reduction in PAI-I concentration in the rosiglitazone-treated patients. Rosiglitazone (20 mg/kg/d) reduced adipose tissue PAI-1 mRNA expression and its plasma levels in wild-type C57 mice with diet-induced obesity ( P <0.001), but this suppressive effect was attenuated in adiponectin knockout mice. Adenovirus-mediated overexpression of adiponectin led to a significant suppression of adipose tissue PAI-1 expression and its circulating concentrations in db/db diabetic mice. Our in vitro study demonstrated that recombinant adiponectin directly inhibited PAI-1 production in 3T3-L1 adipocytes.

Conclusions— The antithrombotic effect of rosiglitazone is mediated, at least in part, through the suppressive effect of adiponectin on PAI-1 production.

Glucagon as a determinant of fibrinolytic activity in men with different stages of glucose tolerance: impact of glucagon on fibrinolysis

Glucagon plays an important role in postprandial hyperglycemia in type 2 diabetes (T2DM), and coexists with insulin resistance and impaired fibrinolysis. We analyzed the response of plasminogen activator inhibitor-1 (PAI-1) to a lipid-glucose-protein test and the relationship between glucagon and PAI-1, tissue plasminogen activator (t-PA) and PAI-1/t-PA in 26 men with normal glucose tolerance (NGT), nine with impaired glucose tolerance (IGT) and 12 with T2DM. Fasting and postprandial PAI-1 were higher in T2DM versus NGT (P < 0.05). In univariate analysis in NGT, fasting and area under the curve (AUC) PAI-1 showed a strong relationship with fasting (P = 0.003, P = 0.006) and postprandial (P = 0.041, P = 0.045) glucagon, t-PA with fasting glucagon (P = 0.014), and PAI-1/t-PA with fasting (P = 0.047) and AUC glucagon (P = 0.017). In IGT fasting, AUC PAI-1 and PAI-1/t-PA were associated with AUC glucagon (P = 0.035, P = 0.032, P = 0.023). In NGT with the fasting metabolic parameters and insulin resistance as independent variables, fasting glucagon remained an independent covariate for PAI-1 and PAI-1/t-PA. In another model, postprandial glucagon was independently associated with PAI-1/t-PA in NGT (P < 0.05). Besides the already established determinants, we found an independent association between glucagon and fibrinolysis in NGT. Further studies are needed to identify the link between glucagon, insulin resistance and hemostasis.

Comparison of the Effects of Pioglitazone and Metformin on Insulin Resistance and Hormonal Markers in Patients with Impaired Glucose Tolerance and Early Diabetes

Impaired glucose tolerance (IGT) is associated with cardiovascular risk factors, but the effects of pioglitazone and metformin on IGT are not well described. We tested the hypothesis that each drug would exhibit antiatherogenic and anti-inflammatory effects in subjects with IGT and early diabetes. The study design was a prospective, randomized, open label, cross-over study. Blood tests, including a 75-g oral glucose tolerance test (OGTT), were performed at baseline and after each treatment. Pioglitazone 15 mg/day or metformin 500-750 mg/day was given for 3 months. Biochemical markers to assess insulin resistance as well as lipid, inflammatory, neurohumoral, and hemostatic factors were included. Twenty-five subjects (17 male, 8 female; age [mean+/-SD]: 61+/-9 years; 84% hypertensive) completed the protocol. Of 25 subjects, 14 were diagnosed as IGT and 11 as diabetes with 75-g OGTT. Pioglitazone significantly reduced fasting glucose (p<0.05), and homeostasis model assessment of insulin resistance (HOMA-IR) (p<0.05) and metformin (p<0.01) reduced cholesterol. Both drugs significantly reduced aldosterone (both p<0.05) and von Willebrand factor (vWF) (both p<0.05). Plasma adiponectin was increased only by pioglitazone (p<0.001). Neither drug affected BP levels. In conclusion, pioglitazone was superior to metformin for the improvement of insulin resistance and adiponectin, and both drugs were equally effective in reducing vWF and aldosterone in subjects with IGT and early diabetes. Early intervention with pioglitazone or metformin therapy may reduce the incidence of future cardiovascular disease in subjects with impaired glucose tolerance or early diabetes.

Relationship of glucose concentrations with PAI-1 and t-PA in subjects with normal glucose tolerance

AIM

To study metabolic risk factors for the development of cardiovascular disease (CVD), including markers of the fibrinolytic system in relation to blood glucose levels in subjects with normal glucose tolerance and fasting blood glucose levels below 5.6 mmol/l.

METHODS

Cross-sectional, community-based study from a primary health-care centre of adult subjects with normal glucose tolerance. Analysis of fasting and 2-h post-load blood glucose concentrations were centralized and related to anthropometric characteristics, metabolic variables, inflammatory markers, and coagulation and fibrinolytic variables.

RESULTS

Increasing fasting blood glucose concentrations within the normal range in subjects with normal glucose tolerance were associated with increasing age, body mass index, and waist circumference, and with increasing concentrations of metabolic risk factors for development of CVD. After adjustment for gender, age, body mass index (BMI), and fasting insulin, levels of plasmin activator inhibitor (PAI-1) and tissue type plasminogen activator (t-PA) increased significantly with increasing levels of fasting glucose within the normal range (P = 0.012 and P < 0.0001, respectively).

CONCLUSIONS

We found risk factors for CVD, specifically key components of the fibrinolytic system, PAI-1 and t-PA, increased with increasing fasting glucose levels even in subjects with normal glucose tolerance. This observation may help to explain the increased risk of CVD with increasing values of fasting glucose in the normal range.

Endothelial Dysfunction and Low-Grade Inflammation Explain Much of the Excess Cardiovascular Mortality in Individuals With Type 2 Diabetes

Objective— The mechanisms responsible for the increased cardiovascular disease risk that accompanies type 2 diabetes (T2D) remain poorly understood. It is commonly held that endothelial dysfunction and low-grade inflammation can explain, at least in part, why deteriorating glucose tolerance is associated with cardiovascular disease. However, there is no direct evidence for this contention.

Methods and Results— In this population-based study (n=631), T2D was cross-sectionally associated with both endothelial dysfunction and low-grade inflammation, whereas impaired glucose metabolism (IGM) was associated only with low-grade inflammation. These findings were independent of other risk factors that accompany T2D or IGM. During a follow-up of 11.7 years (median; range 0.5 to 13.2 years), low-grade inflammation was associated with a greater risk of cardiovascular mortality (hazard ratio, 1.43 [95% CI, 1.17 to 1.77] per 1 SD difference). For endothelial dysfunction, the association with cardiovascular mortality was stronger in diabetic (hazard ratio, 1.87 [95% CI, 1.43 to 2.45]) than in nondiabetic individuals (hazard ratio, 1.23 [95% CI, 0.86 to 1.75]; P interaction=0.06). Finally, T2D-associated endothelial dysfunction and low-grade inflammation explained ≈43% of the increase in cardiovascular mortality risk conferred by T2D.

Conclusions— These data emphasize the necessity of randomized controlled trials of strategies that aim to decrease cardiovascular disease risk by improving endothelial function and decreasing low-grade inflammation, especially for T2D patients.

Tissue factor pathway inhibitor: structure, biology and involvement in disease

Tissue factor (TF)-initiated coagulation plays a significant role in the pathophysiology of many diseases, including cancer and inflammation. Tissue factor pathway inhibitor (TFPI) is a plasma Kunitz-type serine protease inhibitor, which modulates initiations of coagulation induced by TF. In a factor (F) Xa-dependent feedback system, TFPI binds directly and inhibits the TF-FVII/FVIIa complex. Normally, TFPI exists in plasma both as a full-length molecule and as variably carboxy-terminal truncated forms. TFPI also circulates in complex with plasma lipoproteins. The levels and the dual inhibitor effect of TFPI on FXa and TF-FVII/FVIIa complex offers insight into the mechanisms of various pathological conditions triggered by TF. The use of selective pharmacological inhibitors has become an indispensable tool in experimental haemostasis and thrombosis research. In vivo administration of recombinant TFPI (rTFPI) in an experimental animal model prevents thrombosis (and re-thrombosis after thrombolysis), reduces mortality from E. coli-induced-septic shock, prevents fibrin deposition on subendothelial human matrix and protects against disseminated intravascular coagulation (DIC). Thus, TFPI may play an important role in modulating TF-induced thrombogenesis and it may also provide a unique therapeutic approach for prophylaxis and/or treatment of various diseases. In this review, we consider structural and biochemical aspects of the TFPI molecule and detail its inhibitory mechanisms and therapeutic implications in various disease conditions.

Soluble tissue factor is a candidate marker for progression of microvascular disease in patients with Type 2 diabetes

OBJECTIVE

To determine the relationship between abnormalities in blood coagulation and prevalent or incident cardiovascular complications in Type 2 diabetes.

DESIGN AND METHODS

Prospective cohort study of 128 patients with Type 2 diabetes in whom blood samples were collected at baseline and after 1 year of follow-up. All cardiovascular complications at baseline and follow-up were recorded. Forty-three healthy, age-matched subjects served as a control group.

RESULTS

Logistic analysis revealed an independent relationship between soluble tissue factor (TF) and microvascular disease [per pg mL(-1) TF: Exp(B) = 1.008; CI(95%)1.002-1.014], or neurogenic disease [Exp(B) = 1.006; CI(95%)1.001-1.011]. The highest levels of soluble TF were observed in patients with microvascular and neurogenic disease (P < 0.001). Patients with Type 2 diabetes having a soluble TF concentration >300 pg mL(-1) are at a 15-fold higher risk for the presence of microvascular disease and at a 10-fold higher risk for the presence of neurogenic disease compared with the patients with concentrations below 100 pg mL(-1). Soluble TF was correlated with tissue type plasminogen activator, von Willebrand factor antigen, systolic blood pressure and age. Levels of F1' + 2, D-dimer, FVIII activity, t-PA and vWFag were not different among patients with micro-, macro- or neurogenic complications compared with patients without those complications. Forty-eight new micro-, macro- and/or neurogenic complications were diagnosed after 1 year follow-up. With the exception of higher F1 + 2 levels after 1 year all other markers remained unchanged. A trend toward higher soluble TF levels was observed in patients with new microvascular events (P = 0.056).

CONCLUSIONS

Soluble TF is associated with existing microvascular and neurogenic complications in patients with Type 2 diabetes and is a candidate marker for progression of microvascular disease.

Clustering of haemostatic variables and the effect of high cashew and walnut diets on these variables in metabolic syndrome patients

We investigated the effect of a high walnut and cashew diet on haemostatic variables in people with the metabolic syndrome. Factor analysis was used to determine how the haemostatic variables cluster with other components of the metabolic syndrome and multiple regression to determine possible predictors. This randomized, control, parallel, controlled-feeding trial included 68 subjects who complied with the Third National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol criteria. After a 3-week run-in following the control diet, subjects were divided into three groups receiving either walnuts or cashews (20 energy%) or a control diet for 8 weeks. The nut intervention had no significant effect on von Willebrand factor antigen, fibrinogen, factor VII coagulant activity, plasminogen activator inhibitor 1 activity, tissue plasminogen activator activity or thrombin activatable fibrinolysis inhibitor. Statistically, fibrinogen clustered with the body-mass-correlates and acute phase response factors, and factor VII coagulant activity clustered with high-density lipoprotein cholesterol (HDL-C). Tissue plasminogen activator activity, plasminogen activator inhibitor 1 activity and von Willebrand factor antigen clustered into a separate endothelial function factor. HDL-C and markers of obesity were the strongest predictors of the haemostatic variables. We conclude that high walnut and cashew diets did not influence haemostatic factors in this group of metabolic syndrome subjects. The HDL-C increase and weight loss may be the main focus of dietary intervention for the metabolic syndrome. Furthermore, diet composition may have only limited effects if weight loss is not achieved.

Acute hyperglycemia alters von Willebrand factor but not the fibrinolytic system in elderly subjects with normal or impaired glucose tolerance

To assess whether acute hyperglycemia affects fibrinolytic balance in elderly subjects with normal glucose tolerance (NGT) or impaired glucose tolerance (IGT), 40 non-obese elderly subjects (20 NGT, age 68 +/- 8 years; and 20 IGT, age 69 +/- 11 years) were studied. On two experimental days, randomly allocated and spaced 1 week apart, plasma concentrations of glucose, insulin, fibrinogen, tissue plasminogen activator, plasminogen activator inhibitor type 1 and von Willebrand factor (vWF) were measured in each subject at baseline (0) and 30, 60, 90, 120 min after the ingestion of 75 g glucose or a similarly sweet dose of aspartame (250 mg) (control test). In both NGT and IGT elderly subjects, tissue plasminogen activator, plasminogen activator inhibitor type 1 and fibrinogen plasma levels did not significantly change after both oral aspartame and glucose load. In IGT subjects, vWF plasmatic levels decreased after glucose (not aspartame) oral load, reaching the minimum level at 90 min after load (82.7 +/- 7.8 versus 93.7 +/- 10.2, P <0.01). These results demonstrate that acute hyperglycemia does not modify plasma fibrinolysis in elderly subjects. The decrease of plasma concentration of vWF in IGT elderly subjects requires cautious interpretation and further extensive investigations.

Type 2 diabetes is associated with impaired endothelium-dependent, flow-mediated dilation, but impaired glucose metabolism is not; The Hoorn Study

BACKGROUND

Type 2 diabetes (DM2) and impaired glucose metabolism (IGM) are associated with an increased cardiovascular disease risk. Impaired endothelial synthesis of nitric oxide (NO) is an important feature of atherothrombosis and can be estimated from endothelium-dependent flow-mediated dilation (FMD). It is controversial whether or not FMD is impaired in DM2 and IGM. We investigated this issue in a population-based setting.

METHODS AND RESULTS

In the study population (n = 650; 246 with normal glucose metabolism (NGM), 135 with IGM and 269 with DM2; mean age: 67.6 years), FMD and endothelium-independent nitroglycerine-mediated dilation (NMD) were ultrasonically estimated from the brachial artery and expressed as the absolute change in diameter in mm. The increase in diameter (mean +/- standard deviation) in NGM, IGM and DM2 was 0.19 +/- 0.15, 0.19 +/- 0.18 and 0.13 +/- 0.17 MD and 0.45 +/- 0.21, 0.43 +/- 0.24 and 0.45 +/- 0.25 for NMD. After adjustment for age, sex, baseline diameter and percentage increase in peak systolic velocity, DM2, as compared to NGM, remained associated with impaired FMD (regression coefficient beta (95%CI)) as compared to NGM, -0.06 mm (-0.09 to -0.03). IGM was not associated with impaired FMD (beta, 0.01 mm (-0.02 to 0.04)). Additional adjustment for conventional cardiovascular risk factors did not alter these associations. Hyperglycemia or hyperinsulinemia explained 2% of the association between DM2 and FMD. NMD was not associated with glucose tolerance.

CONCLUSIONS

This study shows that DM2 is independently associated with impaired FMD. Hyperglycemia and hyperinsulinemia contribute minimally to this association. Impaired FMD may therefore, in part, explain the increased cardiovascular disease risk in DM2, whereas the normal FMD in IGM suggests that other forms of endothelial dysfunction are important in explaining the increased cardiovascular disease risk in IGM.

Effect of plasminogen activator inhibitor-1 in diabetes mellitus and cardiovascular disease

Concentrations of plasminogen activator inhibitor-1 (PAI-1) are elevated beginning at the stage of impaired glucose tolerance and continuing through the development of diabetes mellitus and the metabolic syndrome. Evolving evidence of the central role of PAI-1 in mediating fibrosis and thrombosis increasingly supports the theory that it is a significant risk factor for macrovascular complications and cardiovascular disease, particularly in patients with diabetes. Several clinical studies have demonstrated a strong correlation between circulating PAI-1 levels and cardiovascular events and mortality. With the potentially severe effects of elevated PAI-1 levels becoming evident, there is increased interest in developing therapies targeted at reducing PAI-1 expression or circulating concentrations. Thus far, weight loss, inhibitors of the renin-angiotensin system, and insulin sensitization through use of thiazolidinediones (TZDs) appear to be the most promising strategies for managing elevated PAI-1 levels. Of these, TZD therapy is the only one that provides the benefits of both long-term glycemic control and improved cardiovascular risk profile. This article reviews the regulation of PAI-1, its activity in various disease states, and available treatment options.

Weight loss reduces tissue factor in morbidly obese patients

OBJECTIVE

To investigate the tissue factor (TF) pathway in clinical obesity and associated metabolic syndrome.

RESEARCH METHODS AND PROCEDURES

Thirty-seven morbidly obese patients (4 men; BMI, 48 +/- 7 kg/m(2); range, 42 to 53 kg/m(2)), undergoing elective gastroplasty for the induction of weight loss, were examined for hemostatic, metabolic, and inflammatory parameters at baseline and 14 +/- 5 months postoperatively.

RESULTS

Weight loss significantly reduced circulating plasma TF (314 +/- 181 vs. 235 +/- 113 pg/mL, p = 0.04), coagulation factor VII (130 +/- 22% vs. 113 +/- 19%, p = 0.023), and prothrombin fragment F1.2 (2.4 +/- 3.4 vs. 1.14 +/- 1.1 nM, p = 0.04) and normalized glucose metabolism in 50% of obese patients preoperatively classified as diabetic or of impaired glucose tolerance. The postoperative decrease in plasma TF correlated with the decrease of F1.2 (r = 0.56; p = 0.005), a marker of in vivo thrombin formation. In subgroup analysis stratified by preoperative glucose tolerance, baseline circulating TF (402.6 +/- 141.6 vs. 176.2 +/- 58.2, p < 0.001) and TF decrease after gastroplasty (DeltaTF: 164.7 +/- 51.4 vs. -81 +/- 31 pg/mL, p = 0.02) were significantly higher in obese patients with impaired glucose tolerance than in patients with normal glucose tolerance.

DISCUSSION

Procoagulant TF is significantly reduced with weight loss and may contribute to a reduction in cardiovascular risk associated with obesity.

Papel de los factores de riesgo en la trombogenicidad sanguínea y los síndromes coronarios agudos

Recent advances in basic science have linked some systemic risk factors to endothelial dysfunction which gives rise to atherosclerotic disease and triggers the progression of thrombotic complications. Superficial erosion of the stenotic plaque can be observed in one-third of acute coronary syndromes (ACS). In these cases the presence of classic risk factors such as diabetes mellitus, hypercholesterolemia and smoking favor a state of "vulnerable blood" or high risk. Increased thrombogenicity can exacerbate thrombus formation and is able to trigger an ACS. The vessel endothelium regulates contractile, mitogenic and thrombotic activities of the vessel wall. Risk factors impair both homeostasis and hemostasis of the vessel wall and promote inflammatory signals. Platelet and monocyte activation favors the expression of tissue factor (TF), thus triggering the coagulation cascade with thrombin generation and clot formation. Increased blood thrombogenicity linked to classic risk factors may be associated with circulating TF levels which are much higher than those observed in healthy subjects without risk factors. These observations not only emphasize the usefulness of aggressive management of risk factors but open a new avenue for future studies to devise therapeutic strategies to treat ACS by inhibiting TF expression.