Do Haemostasis Activation Markers that Predict Cardiovascular Disease Exist?

Association Between Hemostatic Profile and Migraine: A Mendelian Randomization Analysis

OBJECTIVE

To assess support for a causal relationship between hemostatic measures and migraine susceptibility using genetic instrumental analysis.

METHODS

Two-sample Mendelian randomization instrumental analyses leveraging available genome-wide association study (GWAS) summary statistics were applied to hemostatic measures as potentially causal for migraine and its subtypes, migraine with aura (MA) and migraine without aura (MO). Twelve blood-based measures of hemostasis were examined, including plasma level or activity of 8 hemostatic factors and 2 fibrinopeptides together with 2 hemostasis clinical tests.

RESULTS

There were significant instrumental effects between increased coagulation factor VIII activity (FVIII; odds ratio [95% confidence interval] 1.05 [1.03, 1.08]/SD, p = 6.08 × 10^-05), von Willebrand factor level (vWF; 1.05 [1.03, 1.08]/SD, p = 2.25 × 10^-06), and phosphorylated fibrinopeptide A level (1.13 [1.07, 1.19]/SD, p = 5.44 × 10^-06) with migraine susceptibility. When extended to migraine subtypes, FVIII, vWF, and phosphorylated fibrinopeptide A showed slightly stronger effects with MA than overall migraine. Fibrinogen level was inversely linked with MA (0.76 [0.64, 0.91]/SD, p = 2.32 × 10^-03) but not overall migraine. None of the hemostatic factors was linked with MO. In sensitivity analysis, effects for fibrinogen and phosphorylated fibrinopeptide A were robust, whereas independent effects of FVIII and vWF could not be distinguished, and FVIII associations were potentially affected by pleiotropy at the ABO locus. Causal effects from migraine to the hemostatic measures were not supported in reverse Mendelian randomization. However, MA was not included due to lack of instruments.

CONCLUSIONS

The findings support potential causality of increased FVIII, vWF, and phosphorylated fibrinopeptide A and decreased fibrinogen in migraine susceptibility, especially for MA, potentially revealing etiologic relationships between hemostasis and migraine.

Detection of hypofibrinolysis in stable coronary artery disease using the overall haemostatic potential assay

INTRODUCTION

Patients with stable coronary artery disease (CAD) are at risk of arterial thrombosis causing myocardial infarction. Detection of global haemostatic markers of hypercoagulability and hypofibrinolysis may be important for risk stratification and individualised treatment. We examined overall haemostatic potential (OHP) and thrombin generation in a group of stable CAD patients. We also sought to investigate associations between fibrinolytic inhibitors and abnormal global fibrinolysis in these patients.

MATERIALS AND METHODS

Blood samples were collected from 56 patients defined by coronary anatomy as symptomatically stable CAD. Medications were recorded. Samples were analysed using the global coagulation assays OHP and thrombin generation (calibrated automated thrombogram, CAT), platelet aggregometry measured by Multiplate®, and levels of plasminogen activator inhibitor-1 (PAI-1) antigen measured by ELISA. Results were compared with a reference group of healthy controls.

RESULTS

Stable CAD patients displayed increased fibrin and thrombin generation and impaired fibrinolysis (decreased overall fibrinolytic potential, OFP, and increased clot lysis time) compared with healthy controls. No effect of antiplatelet agents or other medications on these parameters was observed using platelet-poor plasma. After multivariate adjustment, OFP of healthy individuals was significantly associated with fibrinogen, but in CAD patients PAI-1 became an important determinant.

CONCLUSIONS

Hypercoagulability of plasma is observed in stable CAD, with both increased thrombin generation and reduced fibrinolytic potential making a significant contribution. The OHP assay may provide a simple method of identifying hypercoagulability in individual patients.

Prothrombin fragments in cardiovascular disease

Prothrombin fragment 1+2 (F1+2), which comes from in vivo cleavage of prothrombin by factor Xa, is considered to be useful for diagnosis of thrombosis. Recognition of the central role of thrombosis in the pathogenesis ofcardiovascular disease has prompted growing interest in the association o F1+2 with cardiovascular clinical syndromes. Increased F1+2 levels have reported in venous thromboembolism, inflammation, cancer, sepsis, acute coronary syndromes, stroke, peripheral arterial disease, atrial fibrillation and during the postoperative period. However, a clear relationship with the appearance of thrombosis has not always been consistently demonstrated. Besides its potential prognostic and diagnostic value, it could also be usefu in assessing the impact of various therapies. However, it should be kept in mind that measurement of hemostasis activation markers has several important biological and methodological disadvantages. Activation markers reflect the presence of thrombosis in any vascular bed, so they are not specific. Furthermore, elevations occur not only in the presence of overt thrombosis but also during the hypercoagulable state. The cutoff level to be used for the definition of elevations is still largely unknown due to the use of different analytical methods, none of which have been standardized until know. Finally, the prognostic value of F1+2 and other markers of coagulation activation remains to be fully defined in future studies.

High-dose tirofiban with enoxaparin and inflammatory markers in high-risk percutaneous intervention

AIM

The study assessed the benefit of high bolus dose tirofiban (HD-tirofiban) with enoxaparin compared with HD-tirofiban with unfractionated heparin (UFH). The study examined markers of platelet activation, thrombin generation and inflammation.

MATERIALS AND METHODS

The study is a prospective single centre open-label trial of patients with high-risk acute coronary syndrome treated with percutaneous intervention (PCI) who were randomized to anticoagulation with UFH or enoxaparin with HD-tirofiban (25 microg kg(-1) bolus). This study measured a panel of platelet activation markers, inflammatory biomarkers and thrombus generation between the two groups.

RESULT

Sixty patients undergoing high-risk PCI were enroled in the study. Platelet inhibition as assessed by whole blood aggregometry following HD-tirofiban infusion was similar in both the UFH and enoxaparin groups. CD40 ligand expression on platelets was significantly reduced following PCI with HD-tirofiban and either UFH or enoxaparin. Following PCI, there were significant reductions measured in other markers of platelet activation including PAC-1, P selectin, factor V/Va, platelet-monocyte aggregates and monocyte expression of Mac-1 as determined by analysis of venous blood samples using flow cytometry. Prothrombin fragment 1+2, D-dimer, von Willebrand factor and high sensitive C-reactive protein levels were significantly less post PCI in the enoxaparin group compared with those patients receiving UFH.

CONCLUSION

The combination of HD tirofiban with enoxaparin resulted in an attenuated inflammatory response when compared with that of the combination of HD tirofiban with UFH.

Metabolic predictors of inflammation, adhesion, and coagulability in healthy younger-aged adults

Elevated levels of inflammatory biomarkers are associated with the pathophysiology of cardiovascular diseases and are predictors of cardiovascular events. The objective of this study was to determine the unique contributions of metabolic factors as predictors of inflammation (C-reactive protein (CRP) and interleukin-6 (IL-6)), adhesion (soluble intercellular adhesion molecule-1 (sICAM-1)), and coagulation (D-dimer) in healthy younger-aged adults. Participants were 83 women and 92 men (mean age 30.04 years, s.d. +/- 4.8, range 22-39) of normal weight to moderate obese weight (mean BMI 24.4 kg/m(2), s.d. +/- 3.35, range 17-32). The primary data analytical approaches included Pearson correlation and multiple linear regression. Circulating levels of CRP, IL-6, sICAM-1, and D-dimer were determined in plasma. Higher levels of CRP were independently associated with higher BMI, a greater waist-to-hip ratio, female gender, and higher triglycerides (P < 0.001). Higher IL-6 levels were independently associated with a greater waist-to-hip ratio (P < 0.01). Higher levels of sICAM-1 were independently associated with higher BMI, higher triglycerides, and lower insulin resistance (P < 0.001). Higher D-dimer levels were independently associated with higher BMI and being female (P < 0.001). Having a higher BMI was most consistently associated with elevated biomarkers of inflammation, adhesion, and coagulation in this sample of healthy younger-aged adults, although female gender, insulin resistance, and lipid levels were also related to the biomarkers. The findings provide insight into the adverse cardiovascular risk associated with elevated body weight in younger adults.

Plasma D-dimer concentration in patients with systemic sclerosis

BACKGROUND

It has been reported that increased plasma D-dimer is a reliable marker of systemic prothrombotic state in patients with cardiovascular diseases.

OBJECTIVES

To evaluate plasma D-dimer concentration in patients with systemic sclerosis (SSc) and healthy controls. We also investigated a possible relationship between the presence of a high plasma D-dimer concentration and clinical and biological parameters in patients with SSc.

METHODS

Measurements of plasma D-dimer concentration were performed in 69 consecutive patients with SSc and 69 age- and sex-matched controls. Clinical and biological findings were compared between patients with and without a high concentration of plasma D-dimer (i.e. >or=500 ng mL(-1)).

RESULTS

Median plasma D-dimer concentrations appeared significantly increased in patients with SSc compared with control subjects (506 vs. 211 ng mL(-1); P<0.001). Furthermore, a high concentration of plasma D-dimer (>or=500 ng mL(-1)) was detected more frequently in patients with SSc than in healthy controls (47.8% vs. 4.5%; P<0.0001). Among vascular manifestations related to SSc, macrovascular impairment responsible for peripheral ischaemia was more frequent in patients with SSc with high levels of D-dimer (>or=500 ng mL(-1)), compared with those without (21% vs. 6%; P=0.05).

CONCLUSIONS

The association between high levels of plasma D-dimer (>or=500 ng mL(-1)) and macrovascular involvement in patients with SSc is likely to be an innovative issue. We suggest that D-dimer levels may be a helpful additional test to identify patients with SSc at risk to develop thrombotic arterial complications (peripheral arterial disease, stroke and coronary event); such patients with high levels of plasma D-dimer (>or=500 ng mL(-1)) may require close monitoring of vascular parameters, including especially macrovascular impairment.

Effect of ambient particulate matter exposure on hemostasis

Epidemiological studies have linked levels of particulate matter (PM) in ambient air to cardiovascular mortality and hospitalizations for myocardial infarction (MI) and stroke. Thrombus formation plays a primary role in potentiating acute cardiovascular events, and this study was undertaken to determine whether pulmonary exposure to PM alters hemostasis. PM was collected from the Chapel Hill, NC airshed and was administered to mice by intratracheal instillation at a dose previously shown to exacerbate myocardial ischemia-reperfusion injury. Twenty-four hours after exposure, an increase occurred in the number of circulating platelets and plasma concentrations of fibrinogen and soluble P-selectin. The concentration of tissue factor pathway inhibitor (TFPI) in plasma was decreased, whereas the plasma concentration of plasminogen activator inhibitor (PAI-1) was increased. Consistent with these observations, bleeding time from a tail-tip transection was shortened. These results provide evidence that PM exposure alters hemostasis in otherwise healthy animals and may thereby promote clot formation and impede clot resolution in susceptible individuals. The results also establish definite hemostatic endpoints that can be used to further investigate the effects of dose and particle characteristics on the toxicity of ambient particles.

Endogenous Plasma Peptide Detection and Identification in the Rat by a Combination of Fractionation Methods and Mass Spectrometry

Mass spectrometry-based analyses are essential tools in the field of biomarker research. However, detection and characterization of plasma low abundance and/or low molecular weight peptides is challenged by the presence of highly abundant proteins, salts and lipids. Numerous strategies have already been tested to reduce the complexity of plasma samples. The aim of this study was to enrich the low molecular weight fraction of rat plasma. To this end, we developed and compared simple protocols based on membrane filtration, solid phase extraction, and a combination of both. As assessed by UV absorbance, an albumin depletion >99% was obtained. The multistep fractionation strategy (including reverse phase HPLC) allowed detection, in a reproducible manner (CV < 30%-35%), of more than 450 peaks below 3000 Da by MALDI-TOF/MS. A MALDI-TOF/MS-determined LOD as low as 1 fmol/μL was obtained, thus allowing nanoLC-Chip/MS/MS identification of spiked peptides representing ~10–6% of total proteins, by weight. Signal peptide recovery ranged between 5%-100% according to the spiked peptide considered. Tens of peptide sequence tags from endogenous plasma peptides were also obtained and high confidence identifications of low abundance fibrinopeptide A and B are reported here to show the efficiency of the protocol. It is concluded that the fractionation protocol presented would be of particular interest for future differential (high throughput) analyses of the plasma low molecular weight fraction.

Plasma D-dimer concentration in patients with systemic sclerosis

Background

Systemic sclerosis (SSc) is an autoimmune disorder of the connective tissue characterized by widespread vascular lesions and fibrosis. Little is known so far on the activation of the hemostatic and fibrinolytic systems in SSc, and most preliminary evidences are discordant.

Methods

To verify whether SSc patients might display a prothrombotic condition, plasma D-dimer was assessed in 28 consecutive SSc patients and in 33 control subjects, matched for age, sex and environmental habit.

Results and discussion

When compared to healthy controls, geometric mean and 95% confidence interval (IC95%) of plasma D-dimer were significantly increased in SSc patients (362 ng/mL, IC 95%: 361–363 ng/mL vs 229 ng/mL, IC95%: 228–231 ng/mL, p = 0.005). After stratifying SSc patients according to disease subset, no significant differences were observed between those with limited cutaneous pattern and controls, whereas patients with diffuse cutaneous pattern displayed substantially increased values. No correlation was found between plasma D-dimer concentration and age, sex, autoantibody pattern, serum creatinine, erythrosedimentation rate, nailfold videocapillaroscopic pattern and pulmonary involvement.

Conclusion

We demonstrated that SSc patients with diffuse subset are characterized by increased plasma D-dimer values, reflecting a potential activation of both the hemostatic and fibrinolytic cascades, which might finally predispose these patients to thrombotic complications.

Endothelial function is impaired in patients with primary antiphospholipid syndrome

INTRODUCTION

The aim of this study was to evaluate endothelial function in patients with primary antiphospholipid syndrome (PAPS).

PATIENTS AND METHODS

Flow mediated (FMD) and glyceryl trinitrate (GTN) induced dilation of the right brachial artery were studied in 25 patients with PAPS and 25 controls matched by age, sex and conventional risk factors for atherosclerosis. Fibrinogen, D-dimer, adhesion molecules, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) antigens and activities were measured.

RESULTS

Mean (SD) FMD was significantly lower in PAPS than in controls (8+/-5% vs. 15+/-6%, P<0.001); GTN-induced dilation did not differ between the groups. There was a correlation between the baseline diameter of the brachial artery and duration of the disease (-0.56, P<0.05) and between GTN induced dilation and duration of the disease (0.51, P<0.05). Concentrations of vascular cell adhesion molecule-1 (P<0.001), intracellular adhesion molecule-1 (P<0.001) and fibrinogen (P<0.05) were higher in patients than in controls but no differences were observed for D-dimer, t-PA and PAI-1 antigens and activities. There was correlation between concentration of vascular cell adhesion molecule-1 and FMD (-0.35, P<0.05) and between intracellular adhesion molecule-1 and FMD (-0.41, P<0.05).

CONCLUSIONS

This study shows that endothelial function is impaired in patients with primary APS, possibly contributing to accelerated atherosclerosis and thromboembolic complications in these patients.