Incidence and factors predictive of recurrent thrombosis in people with non-cirrhotic portal vein thrombosis.

BACKGROUND & AIMS: Clinical guidelines do not recommend long-term anticoagulation in non-cirrhotic splanchnic vein thrombosis (NC-SVT) without underlying thrombophilia because it is assumed that there is a very low risk of recurrent thrombosis (RT). Our first aim was to describe the incidence of RT in people with NC-SVT without an indication for long-term anticoagulation. The second aim was to identify RT risk factors and afterwards verify them in a validation cohort. METHODS: This is a multicentre, retrospective observational study evaluating risk factors for RT in 64 people with NC-SVT of idiopathic/local factor aetiology. In a subgroup of 48 individuals, the potential value of additional thrombophilic parameters to predict RT was analysed. Findings were validated in 70 individuals with idiopathic/local factor NC-SVT. RESULTS: Of the 64 participants in the training cohort, 17 (26%) presented splanchnic and/or extrasplanchnic RT (overall-RT) during follow-up (cumulative incidence: 2, 10, 19, and 34% at 1, 2, 5, and 10 years, respectively). In addition, 53% of people with splanchnic RT were asymptomatic. No clinical or biochemical parameters predicted overall-RT. However, in the 48 people with an additional comprehensive thrombophilic study, factor VIII ≥150% was the only independent factor predicting overall-RT (hazard ratio 7.10, 95% CI 2.17-23.17, p <0.01). In the validation cohort, 19 individuals (27%) presented overall-RT, and it was also independently predicted by factor VIII >150% (hazard ratio 3.71, 95% CI 1.31-10.5, p <0.01). The predictive value of factor VIII was confirmed in both people with idiopathic/local factor aetiology associated NC-SVT. CONCLUSIONS: People with idiopathic/local factor NC-SVT are at risk of overall-RT. Splanchnic RT can be asymptomatic and requires screening for its detection. Values of factor VIII ≥150% may help identify individuals at high risk of overall-RT who could benefit from long-term anticoagulation. IMPACT AND IMPLICATIONS: People with idiopathic/isolated local factor non-cirrhotic portal vein thrombosis were previously thought to be at minimal risk of re-thrombosis and therefore did not receive scheduled follow-up. The results of this study are of special interest for hepatologists treating people with non-cirrhotic splanchnic thrombosis, as they show a 25% incidence of re-thrombosis and support the close follow-up of people with factor VIII >150% to ensure the early identification of new thrombotic events.

Haemostasis patterns in patients with acute-on-chronic liver failure and acute decompensation of cirrhosis including thromboelastometric tests with and without the addition of Protac: a pilot study.

BACKGROUND: Thromboelastometry is considered the best method to assesses hemostasis in liver disease. Diagnostic performance could be improved by adding protein C activators such as thrombomodulin or Protac®. We assessed changes in ROTEM parameters after the addition of Protac® in patients with acute-on-chronic liver failure (ACLF), acute decompensation (AD), and healthy individuals (HI) to define different hemostasis patterns, considering standard and velocity ROTEM parameters, and assess whether Protac® can improve the definition of the pattern. METHODS: Pre-test, we investigated whether diluted EXTEM reagent improved the effect of Protac® on the clotting time (CT)-ratio with and without Protac®. Ten ACLF and 20 AD patients and 21 HI were included in the main study. RESULTS: Standard EXTEM was used in the main study. INTEM CFT, INTEM A5 (inverse), and INTEM TPI (inverse) were the parameters that best differentiated liver disease from HI (ROC AUC, 0.921, 0.906, and 0.928, respectively; all P-values < 0.001). Combining INTEM CFT with EXTEM LI60-ratio only slightly improved the diagnostic performance (ROC AUC, 0.948; P < 0.001). EXTEM LI60 and INTEM maxV-t were the parameters that best differentiated between ACLF and AD patients (ROC AUC, 0.743, P = 0.033; and 0.723, P = 0.050; respectively). Combining EXTEM LI60 + INTEM maxV-t moderately improved the diagnostic performance (ROC AUC, 0.81, P < 0.001). CONCLUSIONS: ROTEM velocity, fibrinolysis parameters and the indices calculated improve the diagnosis in combination with standard parameters (e.g., CFT and A5). Ratios calculated with and without Protac® (e.g., EXTEM LI60-ratio) only slightly increased the diagnostic performance in discriminating hemostasis patterns.

Predicting portal thrombosis in cirrhosis: A prospective study of clinical, ultrasonographic and hemostatic factors.

BACKGROUND & AIMS: Portal vein thrombosis (PVT) is a relatively frequent event in patients with cirrhosis. While different risk factors for PVT have been reported, such as decreased portal blood flow velocity (PBFV) and parameters related with severity of portal hypertension, these are based on retrospective studies assessing only a discrete number of parameters. The aim of the current study was to evaluate the incidence and risks factors for non-tumoral PVT development in a large prospective cohort of patients with cirrhosis. METHODS: We performed an exhaustive evaluation of clinical, biochemical, inflammatory and acquired/hereditary hemostatic profiles in 369 patients with cirrhosis without PVT who were prospectively followed-up. Doppler ultrasound was performed at baseline and every 6 months or whenever clinically indicated. PVT development was always confirmed by computed tomography. RESULTS: Twenty-nine patients developed non-tumoral PVT, with an incidence of 1.6%, 6% and 8.4% at 1, 3 and 5 years, respectively. Low platelet count, PBFV <15 cm/sec and history of variceal bleeding were factors independently associated with a high PVT risk. No relationship between PVT development and any other clinical biochemical, inflammatory and acquired or hereditary hemostatic parameter was found. CONCLUSIONS: In patients with cirrhosis, the factors predictive of PVT development were mainly those related to the severity of portal hypertension. Our results do not support the role of hemostatic alterations (inherited or acquired) and inflammatory markers in the prediction of PVT in patients with cirrhosis. LAY SUMMARY: Patients with cirrhosis and more severe portal hypertension are at higher risk of non-tumoral portal vein thrombosis development. Acquired or inherited hemostatic disorders, as well as inflammatory status, do not seem to predict the development of portal vein thrombosis in patients with cirrhosis.

Congenital antithrombin deficiency in patients with splanchnic vein thrombosis.

BACKGROUND AND AIMS: Splanchnic vein thromboses (SVT) are a rare condition that can be life-threatening. The most severe thrombophilia associated to SVT is antithrombin (AT) deficiency, usually caused by SERPINC1 mutations. Although transitory AT deficiencies and congenital disorders of the N-glycosylation pathways (CDG) have been recently reported as causes of AT deficiency, the current AT clinical screening still only includes anti-FXa activity. This study aims to (a) improve the detection of AT deficiency in SVT and (b) characterize the features of AT deficiency associated with SVT. METHODS: The study was performed in 2 cohorts: (a) 89 SVT patients with different underlying etiologies but in whom AT deficiency had been ruled out by classical diagnostic methods; and (b) 271 unrelated patients with confirmed AT deficiency and venous thrombosis. AT was evaluated by functional (anti-FXa and anti-FIIa) and immunological methods (ELISA, crossed immunoelectrophoresis, western blot), and SERPINC1 sequencing was performed. RESULTS: In 4/89 patients (4.5%) additional alterations in AT were found (two had SERPINC1 mutations, one had a specific variant causing transient AT deficiency and one patient had CDG). In 11 of the 271 patients (4.1%) with AT deficiency and thrombosis, thrombosis was located at the splanchnic venous territory. CONCLUSIONS: Antithrombin deficiency may be underdiagnosed by current clinical screening techniques. Therefore, a comprehensive AT evaluation should be considered in cases of rethrombosis or doubtful interpretation of anti-FXa activity levels. SVT is a relatively common localization of the thrombotic event in patients with congenital AT deficiency.

Study of Biocompatibility of Membranes in Online Hemodiafiltration.

BACKGROUND: The biocompatibility of dialysis membranes is a determining factor in avoiding chronic microinflammation in patients under haemodialysis. Lower biocompatibility has been related to increased inflammatory status, which is known to be associated with cardiovascular events. Classically, cellulose membranes have been considered bioincompatible. A new-generation of asymmetric cellulose triacetate (CTA) membranes allows the performance of high convective transport techniques, but there have been no studies of their biocompatibility. The aim of the present study was to analyze and compare the biocompatibility characteristics of 4 membranes, including CTA, in online hemodiafiltration (OL-HDF) patients. METHODS: We included 15 patients in -OL-HDF. After a 2-week washout period with helixone membrane, each patient was treated with the 4 membranes (polyamide, polynephron, helixone and CTA) for 4 weeks in a randomized order. The other dialysis parameters were kept stable throughout the study. We studied changes in markers of the activation of the complement system, monocytes, platelets, and adhesion molecules with the 4 membranes, as well as inflammatory parameters. RESULTS: Biocompatibility was similar among the membranes. There were no sustained differences in complement activation, measured by C3a and C5a levels, or in platelet activation, determined by levels of P-selectin and platelet-derived microparticles (CD41a+). No differences were observed in activated monocyte levels (CD14+/CD16+) or in plasma levels of interleukin (IL)-1, IL-6, IL-10 or high-sensitivity C-reactive protein, although tumour necrosis factor-α levels decreased when the patients were dialyzed with CTA. No significant differences were found in markers of endothelial damage, assessed by levels of plasminogen activator inhibitor-1 and adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1). CONCLUSION: The 4 membranes evaluated in this study in stable patients on OL-HDF, including the new-generation CTA, show similar biocompatibility with the methods applied.

Coagulation Failure in Patients With Acute-on-Chronic Liver Failure and Decompensated Cirrhosis: Beyond the International Normalized Ratio.

Balanced hemostasis with hypocoagulable and hypercoagulable features may occur in acute-on-chronic liver failure (ACLF). The characteristics and prognostic impact of the coagulation profile in ACLF are unknown. Consecutive patients with ACLF (n = 36) and acute decompensation (AD; n = 24) were included. Blood samples for thromboelastometry (TE) were obtained at admission and 72 hours thereafter. The coagulation profile was evaluated in patients with and without ACLF and in those with and without systemic inflammatory response syndrome. The impact of the coagulation profile on transfusion requirements, bleeding events, and short-term survival was assessed. At admission, patients with ACLF showed more hypocoagulable characteristics compared to AD subjects, with prolonged time to initial fibrin formation and clot formation time and decreased maximum clot firmness and alpha-angle values. TE parameters worsened at 72 hours in ACLF but improved in patients with AD. Prevalence of a hypocoagulable profile (three or more TE parameters outside range) was significantly higher in patients with ACLF either at admission (61% versus 29% in AD; P = 0.03) or during follow-up. Hypocoagulability correlated with systemic inflammation and was associated with higher 28-day (45% versus 16%; P = 0.02) and 90-day (52% versus 19%; P = 0.01) mortality rates but not with transfusion requirements or bleeding. Prolonged time to initial fibrin formation (extrinsic TE assay >80 seconds) and Model for End-Stage Liver Disease score at baseline were independent predictors of 28-day mortality. Conclusion: Patients with ACLF frequently show hypocoagulable features with prolonged time to initial fibrin formation and clot formation time and reduced clot firmness; these alterations worsen after admission, correlate with systemic inflammation, and translate into higher short-term mortality; hypofibrinolysis could contribute to organ failure in ACLF.

Total Circulating Microparticle Levels After Laparoscopic Surgical Treatment for Endometrioma: A Pilot, Prospective, Randomized Study Comparing Stripping with CO2 Laser Vaporization.

STUDY OBJECTIVE: To evaluate serial generation of microparticles (MPs) after laparoscopic stripping or CO2 laser vaporization in the surgical treatment of patients with ovarian endometrioma (OE). DESIGN: A prospective, randomized, blinded, pilot study (Canadian Task Force classification I). SETTING: Tertiary care university hospital from December 2014 to July 2016. PATIENTS: Thirty women with unilateral OE undergoing laparoscopic surgery. INTERVENTION: Patients were randomly selected to undergo either CO2 laser vaporization (L group) or laparoscopic stripping (S group) of OE. MEASUREMENTS AND MAIN RESULTS: Blood samples were collected before surgery and at 2 hours, 24 hours, 1 month, and 3 months after surgery. An MP generation curve after OE surgery was created. MP generation was greater in the S group than in the L group at all time points evaluated. The MP generation curve showed a significantly higher area under the curve after excisional surgery (p <.05). CONCLUSION: The higher MP levels in the S group suggest an increased inflammation and procoagulant response after this procedure.

Enoxaparin reduces hepatic vascular resistance and portal pressure in cirrhotic rats.

BACKGROUND & AIMS: Increased hepatic vascular resistance due to fibrosis and elevated hepatic vascular tone is the primary factor in the development of portal hypertension. Heparin may decrease fibrosis by inhibiting intrahepatic microthrombosis and thrombin-mediated hepatic stellate cell activation. In addition, heparin enhances eNOS activity, which may reduce hepatic vascular tone. Our study aimed at evaluating the effects of acute, short-, long-term and preventive enoxaparin administration on hepatic and systemic hemodynamics, liver fibrosis and nitric oxide availability in cirrhotic rats. METHODS: Enoxaparin (1.8 mg/kg subcutaneously), or its vehicle, was administered to CCl4-cirrhotic rats 24h and 1h before the study (acute), daily for 1 week (short-term) or daily for 3 weeks (long-term) and to thioacetamide-cirrhotic rats daily for 3 weeks with/without thioacetamide (preventive/long-term, respectively). Mean arterial pressure, portal pressure, portal blood flow, hepatic vascular resistance and molecular/cellular mechanisms were evaluated. RESULTS: No significant changes in hemodynamic parameters were observed in acute administration. However, one-week, three-week and preventive treatments significantly decreased portal pressure mainly due to a decrease in hepatic vascular resistance without significant changes in mean arterial pressure. These findings were associated with significant reductions in liver fibrosis, hepatic stellate cell activation, and desmin expression. Moreover, a reduction in fibrin deposition was observed in enoxaparin-treated rats, suggesting reduced intrahepatic microthrombosis. CONCLUSION: Enoxaparin reduces portal pressure in cirrhotic rats by improving the structural component of increased liver resistance. These findings describe the potentially beneficial effects of enoxaparin beyond the treatment/prevention of portal vein thrombosis in cirrhosis, which deserve further investigation.

Increased circulating cell-derived microparticle count is associated with recurrent implantation failure after IVF and embryo transfer.

Cell-derived microparticles (cMPs) are small membrane vesicles that are released from many different cell types in response to cellular activation or apoptosis. Elevated cMP counts have been found in almost all thrombotic diseases and pregnancy wastage, such as recurrent spontaneous abortion and in a number of conditions associated with inflammation, cellular activation and angiogenesis. cMP count was investigated in patients experiencing unexplained recurrent implantation failure (RIF). The study group was composed of 30 women diagnosed with RIF (RIF group). The first control group (IVF group) (n = 30) comprised patients undergoing a first successful IVF cycle. The second control group (FER group) included 30 healthy women who had at least one child born at term and no history of infertility or obstetric complications. cMP count was significantly higher in the RIF group compared with the IVF and FER groups (P < 0.05 and P < 0.01, respectively) (RIF group: 15.8 ± 6.2 nM phosphatidylserine equivalent [PS eq]; IVF group: 10.9 ± 5.3 nM PS eq; FER group: 9.6 ± 4.0 nM PS eq). No statistical difference was found in cMP count between the IVF and FER groups. Increased cMP count is, therefore, associated with RIF after IVF and embryo transfer.

Hypercoagulability in patients with chronic noncirrhotic portal vein thrombosis.

BACKGROUND & AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Risk of thromboembolic events after recurrent spontaneous abortion in antiphospholipid syndrome: a case-control study.

OBJECTIVE: To investigate whether patients having antiphospholipid syndrome (APS) as the only aetiological factor for recurrent spontaneous abortion (RSA) are at increased risk of thrombosis later in life. METHODS: A case-control study at a tertiary university referral centre. The study group consisted of 57 primary APS and RSA women (APS-RSA group). Control groups included: 86 patients with RSA of unknown aetiology (uRSA group), 42 patients with RSA and thrombophilic genetic defects as the only aetiologic factor for RSA (tRSA group) and 30 antiphospholipid antibody (aPL) positive but otherwise healthy women (aPL group). The main measurement was the thrombosis rate after long-term follow-up. RESULTS: APS-RSA patients had a significantly higher 12-year cumulative thrombotic incidence rate compared with the three comparator groups (19.3% vs 4.8%, 0.0% and 0.0%, respectively (log rank), p<0.001). Patients in the APS-RSA group had 25.6 thrombotic events per 1000 patient-years (95% CI 12.8 to 45.9). The OR of thrombosis in relation to the presence (APS-RSA group) or absence (uRSA and tRSA groups) of aPL in patients with RSA was 15.06 (95% CI 3.2 to 70.5). CONCLUSIONS: Our data indicate that a history of RSA associated with aPL is a risk factor for subsequent thrombosis in the long term.

Automated assessment of the neutrophil and platelet activation status in patients with essential thrombocythemia.

Neutrophil and platelet activation are consistently found in essential thrombocythemia (ET), but the techniques employed to demonstrate such abnormalities are complex. To ascertain whether the ADVIA 120 analyzer can be employed to assess neutrophil and platelet activation status in ET, 55 such patients and the same number of matched healthy individuals were studied and the results correlated with neutrophil CD11b and platelet P-selectin expressions measured by flow cytometry. Compared with controls, ET patients had significantly higher values of neutrophil myeloperoxidase index (MPXI), mean platelet volume (MPV), platelet distribution width (PDW), and platelet component distribution width, and significantly lower values of neutrophil lobularity index and mean platelet component (MPC). Patients with the JAK2 mutation had significantly lower values of MPC and higher values of MPV and PDW than those with wild-type allele. A positive correlation was observed between MPXI and neutrophil CD11b expression and a negative correlation between MPC and platelet P-selectin expression. The intensity of the agreement between the variables obtained by the two methods was moderate. These results support the possible value of MPC as surrogate parameter of platelet activation in ET.

Von Willebrand factor levels predict clinical outcome in patients with cirrhosis and portal hypertension.

BACKGROUND AND AIMS: Endothelial dysfunction is a major determinant of the increased hepatic vascular tone of cirrhotic livers. Von Willebrand factor (vWF), P-selectin and 8-iso-PGF2α (isoprostanes), surrogate markers of endothelial dysfunction, are increased in patients with cirrhosis. This study was aimed at exploring in patients with cirrhosis and portal hypertension the relation of these endothelial factors with systemic and hepatic haemodynamics and their possible clinical prognostic value. METHODS: 42 consecutive patients with cirrhosis and portal hypertension had measurement of the hepatic venous pressure gradient (HVPG), cardiopulmonary pressures and vWF, P-selectin and isoprostane levels in blood samples from hepatic and peripheral veins. Patients were followed up to 2 years, death or liver transplantation and any clinical event were recorded. RESULTS: vWF, P-selectin and isoprostanes were increased in patients with cirrhosis compared with controls (p<0.001). vWF levels significantly correlated with HVPG, Child-Pugh score and MELD. Cox model analysis disclosed an independent indirect association of peripheral vWF with survival free of portal hypertension-related events and of transplantation. The vWF cut-off value of 216 U/dl (Youden index) disclosed two different populations of patients with cirrhosis with a highly different probability of survival free of portal hypertension-related events and transplantation (87% vs 22%, p=0.001). The prognostic role of vWF persisted after adjusting for parameters of liver dysfunction and for HVPG. CONCLUSIONS: In patients with cirrhosis and portal hypertension vWF levels correlate with liver function and HVPG and independently predict clinical outcome.

Reduced plasma fibrinolytic potential in patients with recurrent implantation failure after IVF and embryo transfer.

BACKGROUND: Recurrent implantation failure (RIF) following embryo transfer (ET) is a major continuing problem in IVF. Women with haemostatic defects may be at increased risk of miscarriage and preclinical pregnancy loss. The fibrinolytic system is considered, at present, the key to new thrombotic pathogenic mechanisms. Patients with unexplained recurrent miscarriage have an impairment of fibrinolysis, as demonstrated by prolonged clot lysis time (CLT) in association with increased plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI). In this study, we investigated fibrinolytic potential in patients with RIF. METHODS: Three groups of patients were studied: 30 women with RIF (RIF group), 60 patients undergoing a first successful IVF-ET cycle (IVF group) and 60 healthy fertile women (FER group). Plasma CLT was measured using a global fibrinolysis assay. TAFI antigen plasma levels and polymorphisms in the TAFI gene (+505A/G and +1542C/G) were analysed using enzyme-linked immunosorbent assay and allele-specific PCR, respectively. RESULTS: CLT was significantly longer (P < 0.0001 and P < 0.0009, respectively) and TAFI antigen levels were significantly higher (both P < 0.0001) in the RIF versus the IVF and FER groups. A direct relationship between CLT and TAFI antigen levels (r = 0.40; P = 0.001) was detected in the whole study population. There were no differences in distribution of TAFI polymorphisms between groups. CONCLUSIONS: Patients with RIF have reduced plasma fibrinolytic potential, as shown by a prolonged CLT, and this may be explained, at least in part, by increased TAFI antigen levels.

Anticoagulation strategies and risk of bleeding events in critically ill COVID-19 patients.

OBJECTIVE: To evaluate the rate of thrombosis, bleeding and mortality comparing anticoagulant doses in critically ill COVID-19 patients. DESIGN: Retrospective observational and analytical cohort study. SETTING: COVID-19 patients admitted to the intensive care unit of a tertiary hospital between March and April 2020. PATIENTS: 201 critically ill COVID-19 patients were included. Patients were categorized into three groups according to the highest anticoagulant dose received during hospitalization: prophylactic, intermediate and therapeutic. INTERVENTIONS: The incidence of venous thromboembolism (VTE), bleeding and mortality was compared between groups. We performed two logistic multivariable regressions to test the association between VTE and bleeding and the anticoagulant regimen. MAIN VARIABLES OF INTEREST: VTE, bleeding and mortality. RESULTS: 78 patients received prophylactic, 94 intermediate and 29 therapeutic doses. No differences in VTE and mortality were found, while bleeding events were more frequent in the therapeutic (31%) and intermediate (15%) dose group than in the prophylactic group (5%) (p<0.001 and p<0.05 respectively). The anticoagulant dose was the strongest determinant for bleeding (odds ratio 2.4, 95% confidence interval 1.26-4.58, p=0.008) but had no impact on VTE. CONCLUSIONS: Intermediate and therapeutic doses appear to have a higher risk of bleeding without a decrease of VTE events and mortality in critically ill COVID-19 patients.

Antiphospholipid antibodies may impair factor XIIa-dependent activation of fibrinolysis in pregnancy: in vitro evidence with human endothelial cells in culture and monoclonal anticardiolipin antibodies.

OBJECTIVE: The purpose of this study was to analyze the in vitro activation of the contact complex with the use of human umbilical vein endothelial cells (HUVEC) in culture and monoclonal anticardiolipin antibodies (MaCL). STUDY DESIGN: Cultured HUVECs were incubated with pooled plasma from third-trimester pregnant women with the addition (20 mg/mL) of MaCL with anti-beta-2 glycoprotein I activity that was obtained from patients with antiphospholipid syndrome (APS), MaCL from an individual without APS, or from a control patient with immunoglobulin M without aCL activity. Supernatants were evaluated. Activated factors XII and VII, prothrombin-fragment 1 + 2, urokinase-type plasminogen activator (UPA), and differentiating 2 chain UPA were determined. RESULTS: In the cultured HUVEC supernatants, the addition of MaCL increased activated factor VII and prothrombin-fragment 1 + 2, did not modify UPA, and decreased activated factor XII and differentiating 2 chain UPA, in comparison with samples with control immunoglobulin M added. The MaCL without APS activity did not change any parameter that was evaluated. CONCLUSION: MaCL with anti-beta-2 activity that was obtained from patients with APS may interfere in the activation of the contact complex during pregnancy.

Platelet turnover, coagulation factors, and soluble markers of platelet and endothelial activation in essential thrombocythemia: relationship with thrombosis occurrence and JAK2 V617F allele burden.

Patients with essential thrombocythemia (ET) have an increased frequency of thrombosis, but the relationship of both thrombosis and JAK2 V617F allele burden with platelet turnover, acquired activated protein C resistance (aAPCR), and levels of coagulation factors and soluble markers of platelet, and endothelial activation is not well known. In 53 ET patients (26 with a history of thrombosis), reticulated platelets (RP) percentage, aAPCR, platelet tissue factor (TF) expression, and plasma levels of TF, coagulation factors, soluble P-selectin (sP-selectin), soluble CD40 ligand (sCD40L), von Willebrand factor antigen (VWF:Ag), soluble thrombomodulin (sTM), D-dimer and prothrombin fragment 1 + 2 were compared with those in matched healthy individuals and correlated with thrombosis occurrence and JAK2 mutational load. ET patients with thrombosis had significantly higher values for RP percentage, aAPCR, and levels of factors V and VIII, VWF:Ag, sP-selectin, and sCD40L than patients without thrombosis and controls. At multivariate study, RP percentage, factor V levels, and aAPCR were independently associated with an increased risk of thrombosis. Patients with JAK2 mutation had significantly lower levels of free protein S (PS) and higher levels of TF, sP-selectin, sCD40L, VWF:Ag, and sTM than those with wild-type allele. A mutant allele dosage effect (>or= 12%) was observed for TF, sP-selectin, sCD40L, VWF:Ag, and PS levels. These results support a role for platelet turnover, factor V, and aAPCR in the thrombosis of ET as well as the association between JAK2 V617F allele burden and either decreased free PS or increased TF and soluble markers of platelet and endothelial activation.

Increased platelet and leukocyte activation as contributing mechanisms for thrombosis in essential thrombocythemia and correlation with the JAK2 mutational status.

BACKGROUND AND OBJECTIVES: The mechanisms accounting for the increased risk of thrombosis in patients with essential thrombocythemia (ET) are not well known. The aim of the present study was to ascertain the role of platelet and leukocyte activation in the thrombosis of ET. DESIGN AND METHODS: The activation status of platelets and leukocytes was assessed by flow cytometry studies in 49 patients with ET (22 with previous thrombosis and 27 without a history of thrombosis) and in a group of age- and sex-matched healthy individuals. The assessment included platelet P-selectin expression (measured both at baseline and after stimulation with ADP, thrombin, arachidonic acid (AA), and collagen), platelet-neutrophil and platelet-monocyte complexes, determination of CD11b in the neutrophils and monocytes, and expression of tissue factor in the monocytes (mTF). The JAK2 V617F mutation was studied and correlated with platelet and leukocyte activation. RESULTS: As compared with controls, ET patients had significantly higher values of baseline P-selectin and thrombin- and AA-induced platelet P-selectin expression, as well as higher platelet-neutrophil and platelet-monocyte complexes, neutrophil CD11b expression and baseline mTF expression. Platelet P-selectin, monocyte CD11b, and lipopolysaccharide-induced mTF expression was significantly higher in ET patients with a history of thrombosis than in patients without thrombosis. Patients with the JAK2 V617F mutation or thrombosis showed higher baseline and AA-induced platelet P-selectin expression than did those without thrombosis. INTERPRETATION AND CONCLUSIONS: These results would support a role for platelet and monocyte activation in the thrombosis of ET. In these patients, the presence of the JAK2 V617F mutation is associated with higher platelet activation.

[Late T-lymphocyte and monocyte activation in coronary restenosis. Evidence for a persistent inflammatory/immune mechanism?]. / Linfocitos T y monocitos activados en la reestenosis coronaria. ¿Reflejan la persistencia de un mecanismo inflamatorio?

AIMS: This study was made to determine if restenosis after percutaneous coronary angioplasty is associated with acute or chronic inflammatory/immunologic activity, and explored possible relationships with latent infection. PATIENTS AND METHOD: Forty-six consecutive patients underwent elective PTCA and 6 months of angiographic follow-up. Peripheral venous blood samples were obtained at baseline, 24-48 h, and 4-6 months post-intervention. Flow-cytometric methods were used to measure early and late circulating leukocyte activation status. Il-6 and TNF-alpha cytokines, and Il-2 soluble receptor concentrations were determined in all plasma samples. Chlamydia pneumoniae and Cytomegalovirus antibody assays were performed to detect infectious disease. RESULTS: Angiographic coronary stenosis developed in 27 out of 46 patients. At 6 months of follow-up, these patients showed a significant increase in circulating cytotoxic T-lymphocytes CD3+/CD56+ (18.8 7.1 vs 6.12 2.7%; p = 0.005) and activated monocytes (CD11b: 1,383 624 vs 990 484 MFI, p = 0.025; CD64: 76.0 28.7 vs 56.7 21.8 MFI; p = 0.014), with no apparent relation to increased cytokines or latent infectious disease. CONCLUSIONS: Restenosis appears to be associated to inflammatory and immunological activity that persists 6 months after coronary intervention. No relationship was found with the infections studied. The presence of inflammatory activity 4-6 months after PTCA suggess that pharmacological therapeutic interventions to prevent restenosis should be maintained for months.