Activation Of Hemostasis Research Articles

Aspirin effectiveness in patients with rheumatoid arthritis and coronary heart disease who receive non-steroidal anti-inflammatory drugs

Aim. To study coagulation and vascular-platelet haemostasis in patients with rheumatoid arthritis (RA) and coronary heart disease (CHD), who receive various non-steroidal anti-inflammatory drugs (NSAID) in combination with low doses of aspirin. Material and methods. The study included 79 patients (59 women and 20 men; mean age 61,0 years; mean disease duration 8,5 years) with confirmed RA diagnosis. All participants received disease-modifying anti-inflammatory therapy and NSAID, as well as standard pharmacological CHD therapy. The parameters of coagulation and vascular-platelet haemostasis were compared by the type of administered NSAID (diclofenac, tenoxicam, nimesulide, or meloxicam). In total, 40 patients with increased platelet aggregation but no previous antiaggregant therapy were administered aspirin (100 mg/day). Platelet aggregation was reassessed at Day 7–8 of aspirin therapy. The control group included 25 untreated healthy men (mean age 55 years). Results. Activated coagulation haemostasis was observed in 58,2% of patients with RA and CHD, as manifested in increased levels of fibrinogen, soluble fibrin monomer complexes (SFMC), factor XII-dependent fibrinolysis, and von Willebrand factor, compared to controls. The therapy with most NSAID was linked to similar changes in coagulation haemostasis. The patients receiving diclofenac, nimesulide, and meloxicam demonstrated an activation of vascular-platelet haemostasis, as manifested in a significant increase of spontaneous platelet aggregation and ADPinduced platelet aggregation, compared to controls. Among patients receiving tenoxicam, there was a tendency towards a reduction in ADP-induced platelet aggregation (aspirin-like effect). Among patients already receiving diclofenac, nimesulide, or meloxicam, aspirin administration typically resulted in reduced platelet aggregation. In total, 42,4% of the patients did not respond to aspirin therapy. Conclusion. Patients with RA and CHD who receive NSAID are also in need of antiaggregant therapy. The latter should be administered under control of vascularplatelet haemostasis, as in a substantial proportion of these patients (42,4%), aspirin effectiveness is not adequate.

Rotation thromboelastography for the detection and characterization of lipoteichoid acid-induced activation of haemostasis in an in vitro sepsis model

In gram-positive sepsis, lipoteichoic acid (LTA) can induce alterations of haemostasis, potentially leading to disseminated intravascular coagulation. Here, we demonstrate the effects of LTA on haemostasis in an in vitro model of gram-positive sepsis based on rotation thromboelastrography (ROTEM). In this model, LTA leads to time- and dose-dependent shortening of the clotting time (CT), whereas other ROTEM parameters are unaffected. Following heat shock simulation, the LTA effect was blunted with equal CTs in the presence and in the absence of LTA. In addition, the shortening of CT by LTA was inhibited by addition of the protein synthesis inhibitor. Our work demonstrates that the ROTEM system is capable of detecting the LTA effect on haemostasis and provides a sensitive in vitro tool for research into the links between gram-positive sepsis and coagulation.

Very high concentration of D-dimers in portal blood in patients with pancreatic cancer.

Nowadays, increasing attention has been focused on relation between increased D-dimer levels and cancer among patients without detectable thrombosis. The aim of the study was to measure plasma D-dimer levels in portal and peripheral blood in pancreatic cancer patients with absence of venous thromboembolism. Fifteen consecutive patients hospitalized in the Department of General and Transplant Surgery of Medical University in Łódź, from January to March 2012 who underwent surgery due to a pancreatic cancer were enrolled. At laparotomy, portal and peripheral blood were sampled concurrently. D-dimer and fibrinogen levels were measured. Moreover, to investigate overall coagulation function prothrombin time (PT), prothrombin index (PI), international normalized ratio (INR), thrombin time (TT), activated partial thromboplastin time (APTT), TT and APTT index were evaluated. Peripheral plasma D-dimmer levels above normal range were found in 10/15 patients (66,67%), whereas D-dimer above normal values were confirmed in all portal blood samples. Mean D-dimer values were higher in portal than in peripheral blood (3279.37 vs 824.64, by 297%, p=0,025). These discrepancies were accompanied by normal limits of portal and peripheral levels of fibrinogen and comparable coagulation function indexes. Our preliminary study showed the close relation between activation of hemostasis, reflected by elevated D-dimers in portal blood and presence of pancreatic cancer. These data suggest that measurement of portal blood D-dimer levels may be a potentially useful technique for screening the pancreatic cancer.

C0315 Comparison of different D-dimer assays in normal pregnancy

Background: Normal pregnancy is associated with hypercoagulation state and activation of fibrinolysis. D-dimer is an important test of activation of haemostasis. D-dimer concentration progressively increases during normal pregnancy. It is important to establish normal deviations of D-dimer for physiological pregnancy with different assays. Methods: The citrate plasmas of 117 healthy pregnant women at the age of 19 till 40 yearswere evaluated. D-dimer levels weremeasured by ELISA (“Asserachrom D-DI”, Diagnostica Stago, France), quantitative immunoturbidimetric latex agglutination assay (“Auto Blue D-dimer 400”, England) and semi quantitative latex agglutination assay (“DDimer Test”, Diagnostica Stago, Roche, France). STATISTICA 6.0 was used. Results are given as median (Me) with 95% confidence intervals (CI) for each gestational period. A Pb0.05 was considered statistically significant. Results: Results of the ELISA-method were increased both between I and II trimesters (172.45-1109.75 ng/ml FEU vs 244.40-1268.00 ng/ml FEU respectively; pb0.01) and II and III trimesters (244.40-1268.00 ng/ ml FEU vs 512.25-1891.50 ng/ml FEU respectively; pb0.01). Parameters of the quantitative immunoturbidimetric latex agglutination assay were significantly high between I and II trimesters (6.90-468.55 ng/ml vs 57.00-1434.50 ng/ml) only. The results of the latex testwere reported in three categories: normal (b500 ng/ml FEU), positive (500-3000 ng/ml FEU) and over positive (N3000 ng/ml FEU). High D-dimer level was in 68.2% of pregnant women even in I trimester. In II and III trimesters positive and over positive results were increased to 82.4% and 90.9% respectively whereas normal results were 17.6% and 9.1% respectively. Comment: It is recommended that D-dimer be estimated by themost informative ELISA. This quantitative assay adequately evaluates D-dimer level in each trimester of pregnancy.

Effects of low-dose acetylsalicylic acid and atherosclerotic vascular diseases on the outcome in patients with severe sepsis or septic shock

Sepsis and its sequelae of multiple organ failure is one of the leading causes of death in the industrial countries. Several studies have shown that patients who are treated with low-dose acetyl salicylic acid (ASA) for secondary prevention of atherothrombosis may have a lower risk to develop organ failure in the case of critical illness. The benefit of ASA is probably due to an inhibition of platelet activation as well as an increase in the formation of anti-inflammatory lipoxin A4. On the other hand, the effect of ASA could be – at least partially – an indirect one, caused by atherosclerotic vascular diseases as the cause of ASA treatment. Atherosclerosis is considered as a moderate systemic inflammation and we hypothesise that this chronic condition could have an impact on the outcome in sepsis. To get more information on the benefit of ASA in critically ill patients and on possible interference with atherosclerotic vascular diseases, we analysed the medical records of 886 septic patients who were admitted to the surgical intensive care unit (ICU) of a university hospital. Logistic regression analysis indicated that patients who were treated during the ICU stay with ASA (100 mg/d) had a significantly lower mortality. Odds ratios (ORs; with 95% confidential intervals) of 0.56 (0.37–0.84) and 0.57 (0.39–0.83) were calculated for ICU and hospital mortality, respectively. In contrast, statin treatment did not have significant effect on mortality. Diagnosis of atherosclerotic vascular diseases according to ICD classification did not influence ICU mortality but lowered hospital mortality (OR = 0.71 (0.52–0.99)). Subgroup analysis provided preliminary evidence that clopidogrel when given as only anti-platelet drug may have a similar benefit as ASA, but the combination of ASA and clopidogrel failed to improve the outcome. The time course of plasma fibrinogen and procalcitonin levels indicate that ASA seems to reduce the activation of haemostasis and increase the resolution of inflammation. It is concluded that prospective interventional studies should be done to test the use of ASA as novel therapeutic approach in critically ill patients.

COMPUTER-BASED MECHANICAL ANALYSIS OF STENOSED ARTERY WITH THROMBOTIC PLAQUE: THE INFLUENCES OF IMPORTANT PHYSIOLOGICAL PARAMETERS

The thrombus is the inappropriate activation of hemostasis in vascular system. In this paper, biomechanical factors affecting the behaviors of artery with intraluminal thrombus were studies. Results indicated that heart rate and blood viscosity had strong impact on the compliance of the stenosis artery and flow pattern. The alteration in blood viscosity had stronger influence than cardiac cycle on the volume change of the fluid region surrounded by thrombus. von Mises stress measured at the thinnest region of the plaque had the largest time-averaged value. The alteration of these parameters could potentially lead to stress redistribution at intraluminal thrombus.

Activity of vascular hemostasis in milk-fed calves

An investigation of 32 healthy Black Pied and Simmental calves in the milk-feeding stage established a stable content in their blood of acyl hydroperoxides and thiobarbituric acid reactive substances aver- aging in this stage respectively 1.51 D233/ml and 3.53 μmol/L with a tendency toward intensifying the activity of the antioxidant potential of plasma. Against a background of a low level of endotheliocytemia, there was a tendency toward an increase of the index of antiaggregation activity of the vascular wall with all tested inducers (ADP 1.77, collagen 1.63, thrombin 1.53, ristomycin 1.53, epinephrine 1.66) and their combinations (ADP + epinephrine 1.44, ADP + collagen 1.37, epinephrine + collagen 1.49). Endotheliocytes are characterized by intensified production of antithrombin III providing the necessary level of anticoagulants of vascular origin in blood (the index of anticoagulant activity of the vascular wall was 1.32 on average). In this case, secretion of tissue plasminogen activators, revealed upon creating temporary ischemia of the venous wall of calves aged from 11 to 30 days, had a general tendency to intensify (the index of fibrinolytic activity of the vascular wall increased during the stage by 2.1%).

Tissue factor exposing microparticles in inflammatory bowel disease

BackgroundCirculating procoagulant microparticles (MPs) are thought to be involved in the pathogenesis of venous thromboembolism in patients with inflammatory bowel disease (IBD). However, the exposure of tissue factor, the primary initiator of coagulation activation, on microparticles (TF+MPs) and its association with hemostasis activation has not yet been studied in IBD patients. MethodsIn this case–control study 49 IBD patients (28 Crohn's disease, 21 ulcerative colitis) and 49 sex- and age-matched, healthy controls were included. Clinical disease activity (Crohn's Disease Activity Index and Clinical Activity Index, respectively) was assessed and IBD-related data were determined by chart review. Numbers, cellular origin and procoagulant activity of TF+MPs in plasma were determined using flow cytometry and a chromogenic activity assay. D-dimer and high-sensitive C-reactive protein (CRP) served as markers for coagulation activation and inflammation, respectively. The primary endpoint was the number of TF+MPs in IBD patients compared to controls. ResultsMedian number (interquartile range) of TF+MPs was higher in IBD patients than in controls (14.0 (11.9–22.8)×103/mL vs. 11.9 (11.9–19.1)×103/mL plasma, P=0.029). This finding was due to generally higher plasma levels of MPs from platelets and leukocytes in IBD patients. However, the number of TF+MPs was neither correlated with their procoagulant activity and D-dimer nor with disease activity and CRP. ConclusionsIncreased numbers of circulating TF+MPs represent a new facet of hemostatic abnormalities in IBD. However, the lack of association with activation of the coagulation system and disease activity questions their pathogenetic role for venous thromboembolism in this patient group.

PL-01 Predictive potential of haemostatic biomarkers for venous thromboembolism in cancer patients

Venous thromboembolism (VTE) is a common problem in cancer patients. However, the rates of VTE vary widely between different types of malignancies. Furthermore, patient- and treatment-related risk factors contribute to the risk of VTE. The prediction of the individual risk of VTE and the identification of patients with cancer that might benefit from thromboprophylaxis is a major clinical challenge, because the pathogenesis of cancer-associated VTE is multifactorial. Therefore, recent studies have focused on identification of predictive biomarkers for VTE. As there is a close interrelation between cancer and the haemostatic system, which leads to activation of haemostasis and fibrinolysis, biomarkers of the haemostatic system seem to be promising in predicting risk of developing VTE in cancer patients. Some candidate biomarkers or laboratory tests of the haemostatic system including platelet count, soluble P-selectin, tissue factor (TF) and TF-bearing microparticles, coagulation factor VIII, D-dimer, prothrombin fragment 1+2 and the thrombin generation assay have been reported to predict cancer-associated VTE. In addition, it has been shown that risk-scoring models, incorporating clinical parameters and biomarkers, allow risk stratification of cancer patients into groups at high- and at low risk of VTE. The accuracy of a previously established risk scoring model can be improved when it is expanded and biomarkers of the haemostatic system are added. The benefit of a targeted thromboprophylaxis for primary prevention of VTE in cancer patients based on risk assessment by measuring biomarkers or applying risk scoring models has to be shown in interventional clinical trials.

High D-dimer levels are associated with poor prognosis in cancer patients

Systemic activation of hemostasis is frequently observed in cancer patients, even in the absence of thrombosis. Moreover, this activation has been implicated in tumor progression, angiogenesis and metastatic spread. Increased levels of D-dimer, which is a degradation product of cross-linked fibrin, indicate a global activation of hemostasis and fibrinolysis. In a prospective and observational cohort study, we assessed the prognostic value of D-dimer levels for overall survival and mortality risk in 1178 cancer patients included in the Vienna Cancer and Thrombosis Study (CATS). Patients were followed over 2 years at regular intervals until occurrence of symptomatic venous thromboembolism or death. D-dimer levels were measured with a quantitative D-dimer latex agglutination assay The main solid tumors were malignancies of the lung (n=182), breast (n=157), lower gastrointestinal tract (n=133), pancreas (n=74), stomach (n=50), kidney (n=37), prostate (n=133), and brain (n=148); 201 of the patients had hematologic malignancies; 63 had other tumors. During a median follow-up of 731 days, 460 (39.0%) patients died. The overall survival probabilities for patients with D-dimer levels categorized into four groups based on the 1(st), 2(nd) and 3(rd) quartiles of the D-dimer distribution in the total study population were 88%, 82%, 66% and 53% after 1 year, and 78%, 66%, 50% and 30% after 2 years, respectively (P<0.001). The univariate hazard ratio of D-dimer (per double increase) for mortality was 1.5 (95% confidence interval: 1.4-1.6, P<0.001) and remained increased in multivariable analysis including tumor subgroups, age, sex and venous thromboembolism. High D-dimer levels were associated with poor overall survival and increased mortality risk in cancer patients.

P-1267 - Activation of haemostasis in patients with newly diagnosed psychosis before and during antipsychotic treatment: matched case-control antre study

Patients with schizophrenia have an increased risk of venous thromboembolism (VTE). The increased risk is more marked among new users and those prescribed atypical antipsychotic drugs. Platelet activation, changes of plasma coagulation, or fibrinolysis are likely to be responsible for the increase in thrombotic events. In the prospective ANTRE (ANtipsychotics ThRombosis Embolism) study we investigated the plasma levels of markers indicating activation of platelets (soluble P-selectin), coagulation (factor VIII) and fibrinolysis (D-dimers) in a group of thirty patients (seventeen males) with newly diagnosed psychosis (mean age 28.2, range 18–52 years) and in thirty-one healthy volunteers who were matched for age, gender and body mass index. We measured the haemostatic parameters at the time of patients’ admission) and after three and twelve months during outpatient antipsychotic treatment. At baseline there were significantly increased plasma levels of sP-selectin (P = 0.0003), D-dimers (P = 0.0007) and factor VIII (P = 0.0076) in the group of patients with acute psychosis as compared to healthy volunteers. After three and twelve months of patients’ follow up we still observed increased levels of sP-selectin and D-dimers. Plasma levels of factor VIII were significantly increased after 3 months, but decreased after 12 months. We found an increase in markers of activation of haemostasis in patients in acute as well as in chronic stage of psychosis. Our results could explain the possible pathological mechanisms of VTE that are independent from antipsychotic treatment and play a role mainly in the acute phase of the disease.

Haemostatic abnormalities in cats with naturally occurring liver diseases

Alterations in the haemostatic system were characterized in cats with different naturally occurring liver diseases. The study looked at 44 healthy cats and 45 cats with different liver diseases confirmed histologically or cytologically (neoplasia, n=9; inflammation, n=12; hepatic lipidosis, n=13; other degenerative liver diseases, n=11). The following parameters were evaluated: platelet count; prothrombin time; activated partial thromboplastin time; thrombin time; factor (F) II, FV, FVII, FX, and FXIII activities; fibrinogen concentration; activities of antithrombin, protein C, plasminogen, and α(2)-plasmin inhibitor, and D-dimer concentration. In cats with liver diseases, 44/45 (98%) had one or more abnormalities of the coagulation parameters measured. In cats with inflammatory liver diseases, increased D-dimer concentrations and decreased FXIII activity were the most consistent abnormalities and were found in 83% and 75% of cats, respectively. The most common abnormality in cats with neoplastic liver disease was FXIII deficiency (78%). The most consistent abnormalities in cats with hepatic lipidosis were increased FV activity and D-dimer concentration with 54% of cats having values above the reference range for both parameters. Cats with miscellaneous degenerative liver disease most frequently showed FXIII deficiency (64%). The results of this study show that alterations of single haemostatic components are a frequent finding in cats with liver disease. Activation of haemostasis with subsequent consumptive coagulopathy (rather than decreased synthesis) seems to be responsible for these alterations. Increased blood levels of different haemostatic components in cats with inflammatory lesions may be related to an acute phase reaction.

Activity of platelet hemostasis in newborn calves

Healthy newborn Simmental and Black Pied calves with a normal number of platelets in bloodstream don’t have reliable dynamics of the aggregation function of blood platelets with adenosine diphosphate, collagen, thrombin, ristocetin, epinephrine, as well as combinations of ADP + epinephrine, ADP + collagen, and collagen + epinephrine inducers. The level of discocytes in blood on days 1–2 was 78.5, not reliably changing until the end of the neonatal stage. In this case, the number of disco-echinocytes, spherocytes, spheroechinocytes, and bipolar forms of platelets in the bloodstream remained stably low. Maintenance during colostrum feeding of a low intensity of metabolism of endogenous arachidonic acid in platelets and of a low content of ATP, ADP, actin, and myosin in them can be considered important mechanisms providing stability of platelet aggregation activity in calves in the neonatal stage.

Activation of hemostasis in brain dead organ donors: an observational study.

Brain death is associated with a systemic inflammatory response resulting in diminished organ function in individuals transplanted with organs from brain dead donors. As inflammation is accompanied by activation of coagulation, we hypothesized that activation of hemostasis occurs in brain dead organ donors. To assess the hemostatic status in brain dead organ donors. In this study, we systematically assessed the hemostatic system in samples taken from 30 brain dead donors. As controls, blood samples from 30 living kidney donors were included. Compared with the living donors, brain dead donors showed significant platelet activation (assessed by glycocalicin plasma levels), and a profound dysbalance in the von Willebrand factor/ADAMTS13 axis, which is key in platelet attachment to damaged vasculature. Furthermore, compared with the living donors, brain dead donors showed a significantly increased activation of secondary hemostasis with formation of fibrin (assessed by plasma levels of prothrombin fragment 1 + 2, fibrinopeptide A and D-dimer). Finally, brain dead donors showed profound hypofibrinolysis as assessed by a global clot lysis assay, which was attributed to substantially elevated plasma levels of plasminogen activator inhibitor type 1. Collectively, our results show activation of hemostasis and dysregulated fibrinolysis in brain dead organ donors. This prothrombotic state may contribute to formation of microthrombi in transplantable organs, which potentially contributes to deterioration of organ function.

Hypercoagulability in Patients With Chronic Noncirrhotic Portal Vein Thrombosis

Although they have normal liver histology and function, patients with chronic noncirrhotic nontumoral portal vein thrombosis (NC-PVT) frequently have abnormal results from coagulation tests. We investigated the significance of these results. We analyzed blood samples collected from 50 stable patients with NC-PVT secondary to a thrombophilic disorder (32%) or local factor (32%), or that was idiopathic (36%). We measured endogenous thrombin potential (ETP) with and without thrombomodulin, prothrombin time, activated partial thromboplastin time, coagulation factors (I, II, V, VII, VIII, IX, X, XI, and XII), antithrombin, proteins C and S, von Willebrand factor (vWF) antigen, vWF ristocetin cofactor, a disintegrin and metalloprotease with thrombospondin type 1 motifs 13 antigen, D-dimer, plasmin-antiplasmin complex, prothrombin fragment F1+2, activated factor VII, and clot lysis time. Samples from 50 age- and sex-matched healthy individuals were evaluated as controls. Compared with controls, patients with NC-PVT had significant increases in prothrombin time and activated partial thromboplastin time; they had significant reductions in levels of procoagulant factors II, V, VII, IX, X, XI, and XII, and the anticoagulants antithrombin, protein C, and protein S. The patients had increased levels of factor VIII and vWF antigen. Irrespective of etiology, patients with NC-PVT had a significant increase in ETP with thrombomodulin and higher levels of factor VIIa, prothrombin fragment F1+2, D-dimer, and plasmin-antiplasmin complex than controls, indicating in vivo activation of coagulation and fibrinolysis. Patients with NC-PVT have hypercoagulability that is independent of the underlying etiology, based on in vitro analyses of thrombin-generation capacity and increased levels of biomarkers in blood samples. Further studies are required to determine if activation of hemostasis increases the risk for thrombotic events.

Critical Role for CD38-mediated Ca2+ Signaling in Thrombin-induced Procoagulant Activity of Mouse Platelets and Hemostasis

CD38, a multifunctional enzyme that catalyzes the synthesis of intracellular Ca(2+) messengers, cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP), is known to be expressed on platelets. However, the role of CD38 in platelets remains unclear. Our present results show that treatment of platelets with thrombin results in a rapid and sustained Ca(2+) signal, resulting from a coordinated interplay of Ca(2+)-mobilizing messengers, inositol 1,4,5-trisphosphate, cADPR, and NAADP. By dissecting the signaling pathway using various agents, we delineated that cADPR and NAADP are sequentially produced through CD38 internalization by protein kinase C via myosin heavy chain IIA following phospholipase C activation in thrombin-induced platelets. An inositol 1,4,5-trisphosphate receptor antagonist blocked the thrombin-induced formation of cADPR and NAADP as well as Ca(2+) signals. An indispensable response of platelets relying on cytosolic calcium is the surface exposure of phosphatidylserine (PS), which implicates platelet procoagulant activity. Scrutinizing this parameter reveals that CD38(+/+) platelets fully express PS on the surface when stimulated with thrombin, whereas this response was decreased on CD38(-/-) platelets. Similarly, PS exposure and Ca(2+) signals were attenuated when platelets were incubated with 8-bromo-cADPR, bafilomycin A1, and a PKC inhibitor. Furthermore, in vivo, CD38-deficient mice exhibited longer bleeding times and unstable formation of thrombus than wild type mice. These results demonstrate that CD38 plays an essential role in thrombin-induced procoagulant activity of platelets and hemostasis via Ca(2+) signaling mediated by its products, cADPR and NAADP.

Hemostatic changes before and during electrophysiologic study and radiofrequency catheter ablation

We sought to investigate specific hemostasis activation markers during electrophysiologic study (EPS) with consequent radiofrequency catheter ablation (RFA). Sixty patients were studied prospectively during routine EPS with RFA for paroxysmal supraventricular tachycardia. Blood samples were drawn before the insertion of venous sheaths (T0), at the end of EPS (T1), and 30min after completion of RFA (T2). To study coagulation and fibrinolytic and platelet activity, we measured concentrations of thrombin-antithrombin III (TAT), D-dimers (DD), plasminogen activator inhibitor type 1 (PAI-1), tissue-type plasminogen activator (t-PA), and circulating platelet aggregates. The results are expressed as median and show 95% confidence levels. Levels of DD increased from 0.24mg/L at T0 to 0.37mg/L at T1 (P<0.001) and to 0.59mg/L at T2 (P<0.001). TAT levels increased from 5.29μg/L at T0 to 35.80μg/L at T1 (P<0.001) and decreased to 26.30μg/L at T2 (P<0.001). PAI-1 concentration decreased from 30.10μg/L at T0 to 26.4μg/L at T1 (P<0.001). t-PA at T2 increased to 5.10μg/L from 4.75μg/L at T1 (P=0.001). No other differences between corresponding medians were statistically significant (P>0.05). We found that concentrations of DD at T2 versus T1 depended on the number of radiofrequency energy applications (r (S)=0.387; P=0.002). Marked platelet activation was observed from the start of the procedure, without changes during the procedure.

Short-term exposure to particulate matter induces arterial but not venous thrombosis in healthy mice.

Epidemiological findings suggest an association between exposure to particulate matter (PM) and venous thrombo-embolism. To investigate arterial vs. venous thrombosis, inflammation and coagulation in mice, (sub)acutely exposed to two types of PM. Various doses (25, 100 and 200 μg per animal) of urban particulate matter (UPM) or diesel exhaust particles (DEP) were intratracheally (i.t.) instilled in C57Bl6/n mice and several endpoints measured at 4, 10 and 24 h. Mice were also repeatedly exposed to 100 μg per animal on three consecutive days with endpoints measured 24 h after the last instillation. Exposure to 200 μg per mouse UPM enhanced arterial thrombosis, but neither UPM nor DEP significantly enhanced venous thrombosis. Both types of PM induced dose-dependent increases in broncho-alveolar lavage fluid (BALF) total cell numbers (mainly neutrophils) and cytokines (IL-6, KC, MCP-1, RANTES, MIP-1α), with peaks at 4 h and overall higher values for UPM than for DEP. Systemic inflammation was limited to increased serum IL-6 levels, 4 h after UPM. Both types of PM induced similar and dose-dependent but modest increases in factor (F)VII, FVIII and fibrinogen. Three repeated instillations did not or only modestly enhance the proinflammatory and procoagulant status. Compared with DEP, UPM induced more pronounced pulmonary inflammation, but both particle types triggered similar and mild short-term systemic effects. Hence, acute exposure to PM triggers activation of primary hemostasis in the mouse, but no substantial secondary hemostasis activation, resulting in arterial but not venous thrombogenicity.

Activity of Platelet Hemostasis in Children with Spinal Deformities

An increase of adhesion and aggregation functions of platelets in vivo and in vitro was detected in 5-6-year-old children with scoliosis. These disorders were caused by hyperproduction of von Willebrand's factor in the vascular wall and intensification of thromboxane production in blood platelets. Activation of thromboxane formation is the main cause of platelet hyperactivity in children with scoliosis. Correction of platelet hemostasis may include pathogenetically substantiated complex of therapeutic exercises, swimming, and massage.

Genetic regulation of inflammation-mediated activation of haemostasis: Family-based approaches in population studies

Blood coagulation and inflammation play a key role in atherosclerosis and thrombosis. Candidate gene and genome wide association studies have identified potential specific genes that might have a causal role in these pathogenic processes. The analysis of quantitative traits is more powerful as they are closer to direct gene action than disease phenotypes. Thus linkage-based studies on extended families might be useful both to estimate the heritability and to map the genetic loci responsible for the regulation of the trait.Family-based studies may estimate high heritability for thrombosis and quantitative traits regarding both platelet aggregation and blood coagulation. Some specific loci relevant to thrombosis have been identified, with some of them showing a direct pleiotropic effect on the risk of thrombosis.Haemostasis factors can be activated by inflammatory stimuli. Fibrinogen level is genetically correlated with C-reactive protein levels with a link for both traits on chromosomes 12 and 21. Genes related to prostanoid biosynthesis, involved both in inflammation and thrombosis, show high heritability levels in both enzyme expression and prostanoid production.Considering that few large family-based linkage studies have as yet been performed on haemostasis and inflammation-related traits, additional studies are highly needed. We are performing a family-based linkage study on large pedigrees (750 subjects from 23 families with juvenile myocardial infarction and 31 control families), to identify genes responsible for quantitative traits involved in the pathway progressively going from inflammation to haemostasis, cell activation, thrombus formation and cardiovascular events.