Artur Słomka

Tissue‐factor‐bearing microparticles (MPs‐TF) in patients with acute ischaemic stroke: the influence of stroke treatment on MPs‐TF generation

Stroke is an important cause of death and disability throughout the world. Microparticles play a cardinal role in vascular hemostasis. The primary aim of this study was to evaluate the procoagulant activity of microparticles and levels of tissue‐factor‐bearing microparticles (MPs‐TF), tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with acute ischaemic stroke.

Meta-analysis of uninterrupted as compared to interrupted oral anticoagulation with or without bridging in patients undergoing coronary angiography with or without percutaneous coronary intervention

OBJECTIVES To assess safety and effectiveness of different periprocedural antithrombotic strategies in patients receiving long-term oral anticoagulation and undergoing coronary angiography with or without percutaneous coronary intervention (PCI). METHODS Studies comparing uninterrupted oral anticoagulation (UAC) with vit. K antagonists vs interrupted oral anticoagulation (IAC) with or without bridging anticoagulation before coronary procedures were eligible for inclusion in the current meta-analysis. Endpoints selected were 30-day composite of major adverse cardiovascular or cerebrovascular and thromboembolic events (MACCE) and major bleeding. RESULTS Eight studies (7 observational and 1 randomized controlled trial [N=2325pts.]) were included in the analysis. There was no difference in MACCE between UAC and IAC; RR (95%CIs): 0.74 (0.34-1.64); p=0.46 but there was a statistically significant MACCE risk reduction with UAC as compared to IAC with bridging: 0.52 (0.29-0.95); p=0.03. Likewise, there were no statistically significant differences between UAC vs IAC in regard to major bleeding: 0.62 (0.16-2.43); p=0.49; but as compared to IAC with bridging, UAC was associated with statistically significant 65% lower risk of major bleeding: 0.35 (0.13-0.92); p=0.03. Additionally, meta-regression analysis revealed significant linear correlation between log RR of MACCE (β=-4.617; p<0.001) and major bleeding (β=6.665; p=0.022) and mean value of target INR suggestive of higher thrombotic and secondary haemorrhagic risk below estimated INR cut-off of 2.17-2.27 within 30days. CONCLUSIONS Uninterrupted OAC is at least as safe as interrupted OAC, and seems to be much safer than interrupted OAC with bridging anticoagulation in patients undergoing coronary angiography with or without PCI.

Hepcidin Levels Are Increased in Patients with Acute Ischemic Stroke: Preliminary Report

BACKGROUND Our current understanding of iron balance in acute ischemic stroke (AIS) is still limited. The objective of this study was to evaluate levels of iron homeostasis proteins-hepcidin (25-amino acid form) and soluble hemojuvelin (sHJV) together with hepcidin/sHJV ratio (Hepc/sHJV) and soluble transferrin receptor (sTfR) in patients with AIS. In addition, the effect of timing of blood collection, type of stroke treatment, and scores on the National Institutes of Health Stroke Scale were investigated. METHODS Participants comprised 31 patients diagnosed with AIS and 20 matched healthy controls. Venous blood samples were drawn on the first day and on the seventh day after stroke onset. Individuals who had experienced a stroke were subdivided according to type of treatment (thrombolysis group, n = 12 versus nonthrombolysis group, n = 19). Plasma hepcidin, sHJV, and sTfR levels were determined by the enzyme-linked immunosorbent assay method. RESULTS We found that plasma hepcidin levels were significantly higher in ischemic stroke patients compared with the control group (median, 19.82 versus 12.62 ng/mL, P = .04). Furthermore, levels of hepcidin on the seventh day (1 week after diagnosis) were significantly higher in patients treated with thrombolysis than in patients not treated with thrombolysis (median, 22.16 versus 16.21 ng/mL, P = .04). CONCLUSIONS The study provides evidence that AIS is associated with increased hepcidin levels. Stroke treatment may have an influence on hepcidin synthesis.

Haemostatic factors do not account for worse outcomes from ischaemic stroke in patients with higher C-reactive protein concentrations:

Background Although the role of microparticles was recently implicated in stroke pathophysiology, the association between microparticles and inflammation is still not fully understood. The aim of this cohort study of 66 patients was to assess a relation between haemostatic factors, C-reactive protein and clinical outcome of ischaemic stroke. Methods Plasma microparticles procoagulant activity, concentrations of tissue factor-bearing microparticles, tissue factor and tissue factor pathway inhibitor in ischaemic stroke patients were determined with enzyme-linked immunosorbent assays at the time of initial diagnosis, along with serum C-reactive protein concentrations. Patients were divided into two groups depending on their C-reactive protein concentrations (C-reactive protein <3 mg/L; n = 28 vs. C-reactive protein ≥3 mg/L; n = 38). The analysed clinical outcome measures included the National Institutes of Health Stroke Scale and the Barthel Index. Results The two C-reactive protein groups did not differ significantly in terms of microparticles procoagulant activities, tissue factor-bearing microparticles, tissue factor and tissue factor pathway inhibitor concentrations. A significant correlation was observed between tissue factor pathway inhibitor and National Institutes of Health Stroke Scale score at admission (R = 0.3, P = 0.03). Patients with C-reactive protein ≥3 mg/L presented with significantly higher National Institutes of Health Stroke Scale scores (median, 9.00 vs. 5.50, P = 0.002) and lower Barthel Index scores (median, 20.00 vs. 65.00, P = 0.002) than individuals with C-reactive protein <3 mg/L. The C-reactive protein concentrations correlated positively with National Institutes of Health Stroke Scale scores (R = 0.3, P = 0.02) and inversely with Barthel Index scores (R = − 0.4, P = 0.002). Conclusions Altogether, these findings imply that haemostatic parameters (microparticles, tissue factor-bearing microparticles, tissue factor, tissue factor pathway inhibitor) do not account for elevated C-reactive protein concentrations in ischaemic stroke patients.

Bone morphogenetic protein 6—a possible new player in pathophysiology of heart failure

Derangement of bone morphogenetic protein (BMP) signalling was observed in cardiovascular disorders. The present study assesses the diagnostic and prognostic value of BMP6 plasma concentration in chronic heart failure (CHF). 130 CHF patients and 32 controls participated in the study. BMP6 plasma level was measured at baseline. During 12‐month follow‐up death and hospitalisation with CHF exacerbation were recorded. BMP6 was significantly increased in CHF patients with highest concentration in most advanced disease. Individuals with pulmonary congestion or peripheral oedema had higher levels of BMP6 than isovolemic patients. BMP6 was not a predictor of all‐cause mortality or CHF hospitalisation. BMP6 may be involved in pathophysiology of systolic CHF. BMP6 plasma level is related to the disease severity and signs of exacerbation.

Hepcidin: Biological Activity, Analytical Methods in Biological Fluids, Clinical Applications and Antagonists. A Short Review

Hepcidin is a small protein involved in iron metabolism that also exhibits antibacterial and antifungal activities. Since its discovery in 2000 hepcidin has been extensively studied in many research centers. Usage of natural and synthetic hepcidin inhibitors can be applied as a powerful therapeutic tool that targets multiple types of anemia. In addition the pro- tein itself has a potential to placate increased absorption of iron in patients with � -thalassemia. Previous studies have char- acterized mechanisms of hepcidin synthesis as well as its biological activity, however methods enabling estimation of its concentration in biological materials remain obscure. The physiological role of hepcidin in iron metabolism as well as methods of its determination in serum and urine samples are described in this paper. Furthermore, the possible role of hepcidin and its molecular antagonists in health improvement is considered.

Assessing Circulating Factor VIIa–Antithrombin Complexes in Acute Ischemic Stroke: A Pilot Study:

Aim: The goal of this study was to determine the levels of factor VII (FVII), factor VIIa–antithrombin complexes (FVIIa-AT), total tissue factor (TF), and tissue factor-bearing microparticles (MPs-TF) in patients with acute ischemic stroke. Further, we sought evidence of an association between hemostatic markers, time of blood sampling, type of treatment, and patient outcomes. Methods: Venous blood samples were collected from 33 patients on the first day and on the seventh day after stroke diagnosis. Age-matched controls were also included (n = 20). Plasma levels of FVII, FVIIa-AT, total TF, and MPs-TF were measured by enzyme-linked immunosorbent assay. We divided patients into 2 groups: thrombolysis group (n = 13) and nonthrombolysis group (n = 20). Furthermore, evaluation of the National Institutes of Health Stroke Scale and the Barthel Index was performed on the first day and the seventh day. Results: Patients with ischemic stroke showed significantly lower plasma FVII, FVIIa-AT, and total TF levels than controls (median, 112.25% vs 132.05%, P = .004; 107.97 pmol/L vs 154.94 pmol/L, P < .001; 81.74 pg/mL vs 105.71 pg/mL, P < .001, respectively). In contrast, levels of plasma MPs-TF were significantly higher in patients with stroke compared to healthy controls (1.60 pg/mL vs 0.74 pg/mL, P < .001). Additionally, the thrombolysis group had lower FVII levels on the seventh day compared to the first day (median, 109.80% vs 115.74%, P = .04). Conclusion: Factor VII, FVIIa-AT, and total TF are decreased, while MPs-TF are elevated in patients with ischemic stroke. We observed a slight but significant effect of alteplase on FVII plasma levels.

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

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

Evaluation of tissue factor bearing microparticles in the cord blood of preterm and term newborns

Tissue factor (TF) plays a fundamental role in the blood coagulation by binding and activating coagulation factor VII [1]. In fact, recent data suggest that themain source of TF is tissue factor bearingmicroparticles (MPs-TF) [2]. So far, the associations between the levels of TF, MPs-TF and gestational age have not been exhaustively examined. Therefore, the roles of these coagulation biomarkers in the cord blood of newborns should be clarified. In this pilot paperwe sought to investigate the levels of TF and MPs-TF in the cord blood of preterm and term neonates. The studywas performed on the cord blood of 48 newborns (23 preterm and 25 term). According to World Health Organization, preterm birthwasdefined as birth before the37th completedweeks of gestation. From the clinical records we obtained information on gestational age, gender of the infants, birth weight, Apgar score in the 1st, 3rd and the 5thminute,maternal age, gravidity, parity, and themode of delivery. Infants born at b25 completed weeks gestation or with major birth defects were excluded. For the analysis, we also excluded over-term infants (N42weeks of gestational age) and thenewborns or themothers with missing or incomplete prenatal care records. After delivery, blood samples from the umbilical vein were obtained before placenta expulsion and after clamping of the umbilical cord and collected into tubes containing 3.2% sodium citrate. The samples for MPs-TF determination were centrifuged twice. First, blood was centrifuged at 1500g for 15 min in room temperature. Then, plasma supernatant was pipette into Eppendorf tubes and was rapidly centrifuged at 13,000g for 2 min in room temperature. Blood for TF determination was centrifuged at 1500g for 20 min (4 °C). The samples were then collected and stored at−80 °C until examination. Total TF andMPs-TF levels weremeasured using enzyme-linked immunosorbent assays (Hyphen Biomed, France). The details about kits can be found in reference [3]. The data are expressed as a median (Me) and interquartile range (IQR). The two newborn groups were compared using the Mann–Whitney U test. Correlation coefficients were determined by Spearmans test. A probability b0.05 was considered statistically significant (p b 0.05). Table 1 presents the characteristics of the study infants and their mothers. Preterm infants had higher MPs-TF levels than term infants (Me, 10.61 pg/mL versus 5.67 pg/mL), the difference was however only marginally significant (p = 0.05). In infants born prematurely, cord blood plasma total TF levels did not differ significantly from that in term newborns (Me, 51.13 pg/mL versus 49.31 pg/mL, p = 0.47). These results are summarized in Fig. 1. When two groups of newborns were combined together (n = 48), MPs-TF levels showed significant correlations with gestational age and newborns weight (R = −0.3, p = 0.02; R = −0.4; p = 0.003, respectively). In contrast, no