Markers Of Hemostatic Activation Research Articles

Abstract 7652: Plasma markers of hemostasis, fibrinolysis, and angiogenesis prior to androgen deprivation therapy (ADT) in progressive prostate cancer (PC) and associations with long-term thrombotic events and survival

Abstract Background: PC is the third most common malignancy associated with thrombosis, procoagulants may play a role in tumorigenesis and progression, and patients (pts) with PC may have activation of the hemostatic system evident in plasma. The prognostic significance of these markers and their relationship to thrombotic events and overall survival (OS) are under-explored. Methods: Patients >18 years were included if they had progressive PC planned to start ADT, were >6 months from surgery or RT, with no history of prior VTE, unexplained bleeding, current or planned anticoagulation, or an additional active malignancy. Plasma samples were obtained via peripheral venipuncture in tubes containing 3.2% sodium citrate and immediately placed on ice. Samples were analyzed for D-dimer, thrombin-antithrombin complex (TAT), IL-6, IL-8, VEGF, and tissue factor (TF) levels by ELISA. Patients had markers drawn at baseline (prior to initiation of ADT), 1 month, and 6 months after initiation. Results: 40 patients were accrued with a median age of 68 years. At baseline, 29 (73%) had presence of metastases. Baseline median PSA was 15 and median PSA doubling time was 0.32. Baseline median hemoglobin was 13.85, platelets were 218, D-dimer was 322 ng/dL, IL-6 was 0 pg/mL, IL-8 was 0 pg/mL, TAT was 3 ug/L, VEGF was 21 pg/mL, and TF was 26 pg/mL. Median follow-up was 78 months. During follow up, 35 (87.5%) had metastases. 10 (25%) had thrombotic events (6 [15%] venous, 4 [10%] arterial) at median 37 months follow up. Median baseline age of pts with subsequent thrombotic events was 74, vs 67 in those without a thrombotic event. While there was no significant difference in baseline PSA between groups with and without clotting events, pretreatment PSA doubling time was significantly lower in pts with subsequent thrombosis (0.27 vs 0.35, p=0.047). Median baseline D-dimer and TF were higher in patients with subsequent thrombosis (D-dimer: 516 vs 282, p=0.10; TF: 36 vs 24, p=0.12). In univariate analysis, baseline IL-6 and VEGF were associated with OS (IL-6: HR=1.05, 95% CI [1.01,1.09], p=0.025; VEGF: HR=1.02, 95% CI [1.00,1.03], p=0.028). When controlling for presence of metastasis, baseline TAT was associated with OS (HR=1.05, 95% CI [1.00,1.11], p=0.055). Conclusions: Plasma markers of hemostatic activation, fibrinolysis, and angiogenesis prior to initiation of ADT are associated with subsequent thrombotic events and overall survival years later. Further analysis will examine how these markers change over time with hormonal therapy. Citation Format: Jessica S. Palmer, Charlene Thomas, Nicole Jacobs, David Nanus, Scott T. Tagawa. Plasma markers of hemostasis, fibrinolysis, and angiogenesis prior to androgen deprivation therapy (ADT) in progressive prostate cancer (PC) and associations with long-term thrombotic events and survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7652.

Взаимодействие внеклеточных ловушек нейтрофилов и антифосфолипидных антител у онкологических больных

Activation of NETosis processes has been detected in numerous autoimmune and non-autoimmune diseases with increasing concentrations of antiphospholipid antibodies (APA). Neutrophil extracellular traps (NETs) are an important activator of the coagulation cascade and an integral component of arterial and venous clots in cancer patients. Therefore, APA and NETs may be the links in the pathogenesis of thrombosis in cancer patients. Objective. To evaluate the severity of NETosis, hemostatic system activation and APA circulation (anti-β2-glycoprotein 1 (anti-β2-GPI)) in cancer patients. Design. A prospective controlled interventional non-randomized study. Patients and methods. This study included 144 patients who were divided into two groups: the study group – 111 patients aged 34–72 years with malignant breast and gynecological diseases of stages I–III (endometrial cancer, n = 25; ovarian cancer, n = 36; cervical cancer, n = 17; breast cancer, n = 33), and the control group – 33 healthy women. Prior to therapy, serum concentrations of NETosis markers – citrullinated histone H3 (citH3) and human myeloperoxidase antigen (MPO:Ag), markers of hemostatic activation (D-dimer and thrombin-antithrombin complex), and anti-β2-GPI antibodies were assessed. Results. Anti-β2-GPI antibodies were significantly more common in patients with ovarian cancer compared to controls. A significant correlation between the circulation of anti-β2-GPI and the concentration of MPO:Ag was also detected in these patients. All patients in the study group showed a significant increase in the markers of NETosis and hemostatic activation compared to controls. The revealed correlation between the concentrations of NETosis markers and anti-β2-GPI antibodies in ovarian cancer suggests a possible pathogenetic role of APA in the progression of ovarian cancer and NETs-mediated prothrombotic state against the background of APA circulation. It can be assumed that APA formed in cancer patients may be one of the triggers of NETosis. NETosis itself contributes to the development of thrombotic events and stimulates further synthesis of APA. Perhaps it is the activation of NETosis that explains the worse prognosis in cancer patients with APA circulation. Conclusion. The results of this study improve the understanding of interactions between the immune and hemostatic systems. Further research is needed to determine the role of APA in NETosis, as well as the role of NETosis and APA circulation in tumor progression, metastasis, and cancer-associated thrombosis. Key words: neutrophil extracellular traps, NETosis, antiphospholipid antibodies, cancer, neutrophils, anti-β2-GPI

Иммунотромбоз, прогрессия опухоли и метастазирование. Роль интерлейкина-8 и внеклеточных ловушек нейтрофилов

Immunothrombosis, tumor progression and metastasis are inextricably linked. These close interactions are carried out by several actors. Neutrophils are considered as players in the antimicrobial host defense. Activated neutrophils release extracellular traps (NETs) involved in antimicrobial immune response and pathogenesis of various conditions including tumor growth. Neutrophils and interleukin-8 (IL-8) play a key role in the formation of NETs. Objective. To evaluate the interaction between NETs and IL-8, their contribution to the development of immunothrombosis and tumor progression in patients with reproductive system cancers and breast cancer of different stages. Patients and methods. This study included 77 patients with malignant tumors of the endometrium, ovaries, cervix, and breast, and 33 healthy controls. Concentrations of citrullinated histone H3 (citH3), human myeloperoxidase antigen (MPO:Ag), D-dimer, thrombin-antithrombin complexes (TAT), and IL-8 were assessed in all patients before surgical treatment or chemotherapy upon admission to the hospital. Results. It was shown that the concentration of NETosis markers was significantly higher in cancer patients compared to healthy controls, with an increase in indicators against the background of disease progression in stages. Naturally, markers of hemostatic activation were elevated in gynecologic cancer patients, also with increasing indicators against disease progression. The concentration of IL-8 was used as a marker of inflammation in this study, which was significantly elevated in cancer patients. The correlation analysis showed that IL-8 concentrations increased with increasing levels of NETosis markers, demonstrating maximum values at late stages of the disease, which indicates an important role of immunothrombosis in cancer progression and metastasis. Conclusion. The study showed that the concentrations of NETosis markers and IL-8 are elevated in cancer patients, and the degree of this elevation correlates with the stage of the disease. A possible mechanism is capturing of tumor cells by networks, their shielding from immune system, subsequent expression of IL-8 by tumor cells with further involvement of neutrophils and initiation of NETosis. Key words: neutrophil extracellular traps, interleukin-8, immunothrombosis, metastasis, tumor progression, neutrophils

Targeting Thrombophilia in Sickle Cell Disease with Isoquercetin: Results of a Fixed Dose, Single Center, Phase II Randomized Clinical Trial

Introduction: Sickle cell disease (SCD) is characterized by elevated markers of hemostatic activation and thrombophilia manifesting as arterial stroke and venous thromboembolism (VTE). Anticoagulation for VTE in SCD is associated with an increased risk for bleeding. In cancer patients at high risk for VTE, the flavonoid Isoquercetin (IQ) lowered D-dimer and soluble P-selectin possibly by inhibiting plasma protein disulfide isomerase. In a murine model of SCD, IQ with Hydroxyurea (HU) reduced platelet accumulation and fibrin deposition following laser-induced injury. Given these results, we tested the hypothesis that IQ would be relatively safe and reduce thrombo-inflammatory biomarkers in steady state SCD patients. Methods: We conducted a phase II randomized, double blind, placebo-controlled study at the NIH Clinical Center. Eligible patients had SCD, were 60 days remote from an acute VOC or blood transfusion and were on a stable dose of HU. Study subjects (n=46) were randomly allocated to receive either Isoquercetin 1000 mg daily (n= 23) or placebo (n= 23) for 28 days and were monitored at the beginning and at completion of study. The primary endpoint of the study was the ELISA measured change in plasma sP-selectin levels after 28 days of placebo or study drug exposure. Analysis was performed on an intention to treat principle. D-dimer levels and Thrombin anti-thrombin (TAT) complex were measured by Immunoturbidimetric assays and ELISA. Statistical analyses was performed using analysis of covariance (ANCOVA) and Wilcoxon rank-sum test. Results: The mean (± SD) age of the study population was 40 years (± 11.57), and 56% were female. The majority had HbSS disease and were receiving HU therapy. A subset (28%) reported a prior history of venous thrombosis (VTE) and four of these were on extended duration oral anticoagulation (Table 1). Baseline characteristics between the two study groups were relatively similar. For the primary endpoint, at the end of study the effect of IQ on the change in plasma sP-selectin levels after adjusting for the baseline was not significant (Figure 1) (IQ mean change= 0.10 ± 6.53 vs. placebo mean change= 0.74 ± 4.54; p= 0.66). Since treatment with HU could confound a treatment effect of IQ in a small sample, we compared the change of sP-selectin among those receiving and not receiving HU but did not find any significant difference (p= 0.67). In a sensitivity analysis we did not find an interaction between HU and IQ treatment (p= 0.48). A similar examination for the potential role of VTE history (n= 5 in IQ and n= 8 in placebo arm) as a confounder did not show a VTE effect on change in sP-selectin (p= 0.68) nor an interaction between VTE history and treatment (p= 0.65). In addition to the primary outcome, we explored the effect of IQ treatment on traditional biomarkers of thrombosis. In contrast to studies in patients with cancer, IQ exposure for 28 days did not have a noticeable effect on change from baseline in either D-dimer levels (IQ mean change= 0.15 mcg/ml ± 0.92 vs. placebo mean change= -0.10 mcg/ml ± 2.11; p= 0.82) or thrombin-antithrombin (TAT) complexes (IQ mean change= 0.09 ng/ml ± 1.60 vs. placebo mean change= -0.05 ng/ml ±1.29; p= 0.57). Conclusion: Short term Isoquercetin exposure in steady state SCD did not appreciably lower plasma sP-selectin but was well tolerated, safe and did not have bleeding side effects. Clinical studies of higher dose IQ with greater exposure duration may yield more measurable effects on antithrombotic activity. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Upregulation of Cortisol in Sepsis and Its Association with Markers of Hemostatic Dysregulation

Introduction:Sepsis is a life-threatening condition in which the host's response to a systemic infection contributes significantly to mortality. Patients with sepsis are at risk of developing a coagulation disorder leading to disseminated intravascular coagulation (DIC). In DIC, widespread activation of the coagulation cascade leads to microvascular thrombosis and organ failure. This consumes platelets and coagulation factors, putting the patient at risk for bleeding. Cortisol is a steroid hormone released in response to stress. Cortisol levels have been found to be increased in sepsis patients, and high cortisol levels have been correlated with increased mortality. However, the association of cortisol levels with the severity of coagulopathy in patients with DIC remains unclear. Cortisol levels may also be relevant to disease progression as a link between the stress response and the immune system. The purpose of this project is to assess the association of plasma cortisol levels with severity of coagulopathy in a population of patients with sepsis and clinically confirmed DIC. Furthermore, the association of cortisol with markers of hemostatic status, inflammation, and platelet function were also assessed.Materials and Methods:Citrated, de-identified plasma samples were collected from 52 adults with sepsis and suspected DIC at the time of ICU admission. Samples were collected at the University of Utah and transferred to LoyolaUniversity Chicago under an IRB approved protocol. Plasma samples from healthy individuals were acquired from a commercial source (George King Biomedical, Overland, KS). Samples were stored at -80˚C prior to analysis. Platelet count was determined as part of standard clinical practice. PT/INR and fibrinogen were measured using standard techniques on the ACL-ELITE coagulation analyzer. Cortisol, D-dimer, PAI-1, CD40L, inflammasomes (NLRP3), and microparticles were measured using commercially available ELISA kits and were performed according to the manufacturer's instructions. DIC score was calculated using the ISTH scoring algorithm. A score of 0-2 was classified as no DIC, 3-4 was classified as non-overt DIC, and 5 or greater was classified as overt DIC. Results were analyzed using GraphPad Prism.Results:Cortisol showed significant variation based on DIC status (Kruskal-Wallis ANOVA, p < 0.0001) . Patients with non-overt DIC and overt DIC exhibited significantly elevated cortisol levels compared to healthy controls (p < 0.0001 for both groups). Furthermore, cortisol levels showed significant variation amongst sepsis patients based on DIC score. Patients with sepsis and overt DIC had elevated cortisol compared to patients with sepsis and no DIC (p = 0.0069). Data is shown in Figure 1.Correlations were evaluated between cortisol and the hemostatic markers platelets, fibrinogen, INR, D-Dimer, and PAI-1 as well as with the inflammatory marker, inflammasomes (NLRP3) and the platelet markers CD40L and microparticles. Cortisol showed significant correlations with D-Dimer, PAI-1, and INR. (D-Dimer Spearman r = 0.480, p = 0.001; PAI-1 Spearman r = 0.415, p = 0.002; INR Spearman r = 0.305, p = 0.037). No significant correlations were observed between cortisol and the markers of inflammation or platelet activation.Conclusions:Cortisol showed a significant association with hemostatic status in a population of patients with sepsis and well-defined coagulopathy. Cortisol levels were significantly elevated in patients with overt or non-overt DIC compared to healthy individuals and in patients with overt DIC compared to those with sepsis without DIC. Cortisol also showed significant correlations with markers of hemostatic activation but not with markers of inflammation and platelet activation. This suggests that elevated levels of cortisol may play a specific role in the progression of hemostatic dysregulation observed in sepsis and DIC. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Prophylactic fresh frozen plasma and platelet transfusion have a prothrombotic effect in patients with liver disease

Background and AimsPatients with liver disease acquire complex changes in their hemostatic system, resulting in prolongation of the international normalized ratio and thrombocytopenia. Abnormalities in these tests are commonly corrected with fresh frozen plasma (FFP) or platelet transfusions before invasive procedures. Whether these prophylactic transfusions are beneficial and truly indicated is increasingly debated. In this study, we studied ex vivo effects of FFP and platelet transfusions in patients with liver disease‐associated hemostatic changes in a real‐life clinical setting. MethodsWe included 19 patients who were deemed to require prophylactic FFP transfusion by their treating physician and 13 that were prescribed platelet transfusion before a procedure. Hemostatic status was assessed in blood samples taken before and after transfusion and compared with healthy controls (n = 20). ResultsEx vivo thrombin generation was preserved in patients with liver disease before FFP transfusion. Following FFP transfusion, both in and ex vivo thrombin generation significantly increased, as evidenced by a 92% and 38% increase in thrombin‐antithrombin and prothrombin fragment 1 + 2 levels, respectively, and a 20% increase in endogenous thrombin potential. Platelet counts increased from 28 [21‐41] × 109/L before to 43 [39‐64] × 109/L after platelet transfusion (P < .01), and was accompanied by increases in in vivo markers of hemostatic activation. ConclusionsFFP and platelet transfusion resulted in increased thrombin generation and platelet counts in patients with liver disease, indicating a prothrombotic effect. However, whether all transfusions were truly indicated and had a clinically relevant effect is questionable.

Clinical and laboratory predictors of deep vein thrombosis after acute stroke

BackgroundDeep vein thrombosis (DVT) is a common complication of acute stroke, but the new incidence in the era of improved specialist input in stroke care is yet unknown. The models for VTE diagnosis is well established, but prediction models to target at-risk patients for pharmacological prophylaxis is lacking and requires further research, particularly in the aftermath of acute stroke. ObjectivesTo predict DVT after acute stroke using markers of haemostatic activation and stroke severity scores. MethodsWe examined the clinical utility of laboratory factors such as thrombin generation, D-dimer, fibrinogen alongside clinical factors (National Institute of Health Stroke Scale and Barthel Index) in the prediction of asymptomatic DVT, among 92 consecutively admitted patients. ResultsOne in five patients (19.6%) had objectively confirmed DVT (6 proximal, 12 distal). Thrombolytic therapy did not protect against DVT, with 21% (6/29) of patients treated with r-tPA went on to develop DVT. Thrombin generation and fibrinogen had no clinical utility, but D-dimer at baseline and week 2 had high clinical potential in the prediction of asymptomatic DVT (2425ng/mL versus 1010ng/mL; p=0.001) and (2240 Vs 970ng/mL; p<0.001) respectively. Patients with DVT had worse stroke severity, and are functionally less able, with lower Barthel index (p=0.05), and high National Institute of Health Stroke Score (p=0.07). ConclusionThrombolytic therapy and specialist stroke intervention does not protect against DVT risk. D-dimer concentration within 48h of acute stroke is independently associated with development of DVT. This observation would require confirmation in a large study.

Pan-Selectin Antagonist Rivipansel (GMI-1070) Reduces Soluble E-Selectin Levels While Improving Clinical Outcomes in SCD Vaso-Occlusive Crisis

Introduction: The pan-selectin antagonist rivipansel (GMI-1070) reduced intravascular arrest of red/white blood cell aggregates and improved blood flow and survival in a mouse model of sickle cell disease vaso-occlusive crisis (SCD VOC). In a Phase 1 study of GMI-1070 infusion in SCD adults at steady state (not in VOC), GMI-1070 decreased markers of cellular activation including neutrophil integrins, platelet/neutrophil aggregates, soluble adhesion molecule concentration; and markers of hemostatic activation. Furthermore, in a randomized Phase 2 study of SCD patients, treatment of VOC with GMI-1070 improved clinical outcomes such as time to resolution of crisis, time to discharge, and IV opioid use. Herein we report on the effect of GMI-1070 on biomarkers of cellular and hemostatic cascade activation from this Phase 2 trial.Methods: Patients in VOC enrolled in a prospective, randomized multi-center double-blind Phase 2 trial, ages 12-60 with HbSS or HbSB0thalassemia were treated with GMI-1070 q12h or placebo, in addition to standard treatment per institutional practice, until resolution of VOC. Clinical outcomes and pharmacokinetics have been previously reported (ASH 2013 Abstracts 775, 776, and 2206). Biomarker blood samples were drawn prior to study drug, and on a sparse sampling basis at times starting 30 minutes after initial dose and continuing until 36 hours after the last dose. Analytes measured included: soluble adhesion molecules E-selectin (sEsel), P-selectin, L-selectin, intercellular adhesion molecules 1 and 3, vascular cell adhesion molecule-1; and tissue factor and thrombin-antithrombin complexes by ELISA. At some sites, surface expression of monocyte b2 integrins MAC-1 & LFA-1 and platelet-monocyte aggregates were also measured by flow cytometry. Comparisons were made between the GMI-1070 and placebo groups, and serial expression levels were compared over time. Subgroup analyses were performed by hydroxyurea (HU) use, age group, baseline WBC, and 'responders’ based on clinical outcomes. A mixed effect model was used to test the LS means difference at each time point and ANCOVA model was used to analyze the nadir, peak, and last dose values.Results: ELISA and flow cytometry samples were collected from 70 and 15 subjects, respectively. Soluble E-selectin levels were reduced for the group on GMI-1070 compared to placebo throughout hospitalization, and the differences were statistically significant at some time-points (Figure 1). Baseline sEsel levels were similar; but the peak, nadir, and level at last dose were all lower in the GMI-1070 group (Figure 2). Exploratory subgroup analysis by HU use, age group, response as measured by visual analog scale or opiate use, frequency of VOC in the past, and baseline white blood cell count revealed consistently lower sEsel levels in the GMI-1070 group. Many, but not all, of these differences reached statistical significance.Conclusion: GMI-1070 use during VOC resulted in consistent and significant reductions of sEsel, overall and in sub-groups as compared to placebo. These findings are consistent with the hypothesized effect of GMI-1070 on endothelial activation and/or apoptosis, mediated by inhibition of E-selectin, although an effect on sEsel clearance cannot be excluded. A Phase 3 study is planned to evaluate efficacy and safety of GMI-1070 as treatment for VOC. Soluble E-selectin concentrations may be useful as a biomarker of pharmacodynamic effect. [Display omitted] [Display omitted] DisclosuresWun:GlycoMimetics: Research Funding; Pfizer: Steering Committee, Steering Committee Other; Emmaus Medical: Consultancy. Telen:GlycoMimetics: Research Funding; Pfizer: Consultancy; Dilaforette: Research Funding. Krishnamurti:GlycoMimetics: Research Funding. McCavit:GlycoMimetics: Research Funding; Pfizer: Consultancy. DeCastro:GlycoMimetics: Research Funding. Flanner:GlycoMimetics: Employment, Equity Ownership. Kuypers:GlycoMimetics: Research Funding. Larkin:GlycoMimetics: Research Funding. Rhee:GlycoMimetics: Consultancy. Magnani:GlycoMimetics Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees. Thackray:GlycoMimetics: Employment, Equity Ownership.

Plazma D-dimer düzeyleri akciğer kanserinde prognoz için bir belirteç olabilir mi?

Plasma concentrations of circulatory markers of hemostatic activation which may be associated with tumor growth and dissemination have been shown to predict prognosis in malignancy. The present study was designed to investigate the prognostic value of plasma D-dimer level in lung cancer. Plasma levels of the D-dimer in 138 lung cancer patients [98 non-small cell lung cancer (NSCLC), 40 small cell lung cancer (SCLC)] were measured before the initiation of any therapy and each chemotherapy. There were 124 (89.9%) men and 14 (10.1%) women with a mean age of 62.8 years (range 38-84). There were no statistically significant differences among the histopathologic types for NSCLC patients. Stage IIIA NSCLC group had statistically significant higher D-dimer level than stages I-II and IV. D-dimer levels were increased significantly after 4 cycles of chemotherapy in progressive disease. The median survival times in NSCLC patients were 26.6 months (95% CI, 17.6-35.6) and 15.9 months (95% CI, 4.2-27.7; p= 0.037) respectively, for patients with a low D-dimer level (≤ 1.2 ng/L) and a high D-dimer level (> 1.2 ng/L).With the cox-regression analysis, the plasma level of D-dimer and tumour stage were identified as independent predictive factors of the survival. These results suggest that plasmalevel of D-dimer can act as a predictive factor of decreased survival and a poor response to the treatment in lung cancer.

Elevation of Hypercoagulability Markers in Hemoglobin SC Disease

AbstractAbstract 3227 Background:Sickle cell anemia (SCA) patients present an elevated rate of thrombotic complications and increased biological markers of hemostatic activation. Hemoglobin SC disease (HbSC) is the second most prevalent hemoglobinopathy after SCA (homozygous HbSS), has specific clinical and pathological characteristics that may differ from SCA, and viscosity appears to be a hallmark of the disease. Studies have shown an increase in thrombotic events in HbSC patients, especially pulmonary embolism, however, not much is known about the coagulation activation in this population. We herein aimed to evaluate the hypercoagulability markers in HbSC disease and their associations with patients' clinical and laboratory characteristics. Patients and Methods:This was a cross-sectional study performed on a cohort of 41 adult HbSC (mean age of 43 years) and 58 adult HbSS patients (mean age of 36 years), all in steady-state, and 25 healthy age-matched controls. We evaluated the expression of tissue factor (TF), the physiological initiator of coagulation, and thrombin-antithrombin complex (TAT), a final marker of coagulation activation. Leukocyte TFmRNA expression was analyzed by real time quantitative PCR and TAT plasma levels were measured by ELISA. Comparisons between the two patient groups and controls were performed using Kruskal-Wallis test followed by Dunn's Multiple Comparisons test. Fisher's exact test and Mann-Whitney's U test were used to compare patients' clinical complications and laboratory characteristics. Spearman's rank test was used for correlations analysis. Results:Relative TF mRNA expression was significantly up-regulated in HbSC patients when compared to controls (2.6 vs. 1.2), however levels of TF were lower in HbSC than HbSS patients (2.6 vs. 3.3) (P<0.0001). Confirming the biological relevance of TF expression, TAT plasma levels were also higher in HbSC patients in comparison to controls (4.2 vs. 2.4), and lower in HbSC than HbSS patients (4.2 vs. 7.3); (P<0.0001). In the analyses of the HbSC cohort, TAT levels presented significant positive correlations with inflammation markers: leukocyte (r=0.5; P=0.001), monocyte (r=0.4; P=0.01), and platelet counts (r=0.5; P=0.002); and hemolysis markers: reticulocyte counts (r=0.4; P=0.01) and lactate dehydrogenase levels (r=0.6, P=0.0001). We also evaluated associations between TAT levels and clinical complications: stroke, pulmonary arterial hypertension, acute thoracic syndrome, retinopathy, osteonecrosis, leg ulcers, autosplenectomy and microalbuminuria. HbSC patients with retinopathy had significantly higher TAT levels (4.7 vs. 3.9; P=0.03) when compared with patients without this complication. TAT levels were also higher in patients with autosplenectomy (4.8 vs. 3.8; P=0.004), and in patients with osteonecrosis, although this had borderline statistical significance (4.6 vs. 3.9; P=0.06). TF expression significantly correlated with monocyte counts (r=0.6; P=0.01). Conclusions:Our results indicate that HbSC disease patients present elevated coagulation activation markers when compared to controls, although not as intense as seen in SCA. Thrombotic complications in HbSC patients have been mainly linked to the hyperviscosity present in this disease. Our data suggest that inflammation and hemolysis are also important factors contributing to hemostatic activation, which may participate in the pathophysiology of very prevalent chronic complications of HbSC disease: retinopathy and osteonecrosis. Interestingly, in our cohort, patients with autosplenectomy had higher levels of pro-coagulant markers, possibly due to a higher intravascular hemolytic rate and elevated peripheral blood counts. Although HbSC disease is considered a milder form of SCA, autopsy studies have shown that mortality by pulmonary embolism is more frequent in HbSC disease than in SCA, being the second cause of mortality in these patients (Manci et al, 2003). Studies addressing the pathophysiology of coagulation activation in HbSC disease are lacking. Low numbers of cases of HbSC disease are usually included in studies focusing mainly in SCA, and the results are very variable, probably due to the small numbers of patients. In view of the high prevalence and morbimortalilty of thrombotic complications in this population, we believe that future studies should focus on a better understanding of hypercoagulability in HbSC disease. Disclosures:No relevant conflicts of interest to declare.

Plasma microparticles are not elevated in fresh plasma from patients with gynaecological malignancy — An observational study

Objectives Gynaecological cancer is common. It is highly amenable to effective treatment, but thrombosis remains a common complication. There is controversy about whether microparticles (MPs), particularly tissue factor (TF) positive MPs, are increased in patients with malignancy and/or thrombosis. We therefore set out to investigate the relationship between MPs of different cellular origins, in patients with gynaecological malignancy. We hypothesised that patients with gynaecological malignancy have increased numbers of MPs. We measured MPs released by different cell types in these patients, and correlated the results with measures of haemostatic activation. Methods We measured the number of platelet-derived MPs (PMPs), endothelial cell-derived MPs (EMPs), leucocyte-derived MPs (LMPs), TF+ve MPs and annexin V (AV) binding MPs in fresh plasma by flow cytometry in patients with gynaecological malignancy and a control group. We also measured D-dimers, prothrombin fragments 1 and 2 (PF1&2) and thrombin–antithrombin (TAT) complexes as indirect markers of haemostatic activation. Results The number of MPs (from all cell types) was similar in the two patient groups, with no significant differences. The number of circulating TF+ve MPs was also similar between the two groups. D-dimers (p < 0.001) and PF1&2 (p = 0.009) were significantly higher in the malignant group reflecting haemostatic activation, but there was no correlation between the level of D-dimers, PF1&2 and TAT and MP numbers. Conclusion Using fresh samples, MPs were not significantly increased in patients with gynaecological malignancy. There was, however, evidence of haemostatic activation in the patients with malignancy, but no correlation between the number of MPs and haemostatic activation.

Tissue Factor Procoagulant Activity and Coagulation Activation In Sickle Cell Disease: Relationship with Biomarkers of Hemolysis and Inflammation

AbstractAbstract 4210Several lines of evidence suggest that hemostasis is activated in patients with chronic hemolytic anemias, including sickle cell disease (SCD), with documented laboratory evidence for increased thrombin generation, fibrin formation, and elevated circulating levels of tissue factor (TF). TF, a cell surface receptor for factor-VII/VIIa, is the physiologic cellular activator of hemostasis. Previous studies have identified a circulating pool of TF that is associated with both hematopoietic cells and microparticles. We investigated: (i) whether cell-associated or microparticle-associated TF contributes to thrombin generation in SCD; and (ii) whether any of the SCD-related pathobiologic processes such as hemolysis, inflammation and/or endothelial activation contribute to hemostatic perturbations. The study cohort included 40 subjects with SCD in steady state (ages 2 to 21 years), 25 with SS and 15 with the SC genotype. Whole blood TF (WBTF) and microparticle-associated TF (MPTF) were measured using a two-stage functional clotting assay. Besides the early stage markers (WBTF and MPTF), we also assessed end-stage markers of thrombin generation and fibrin formation [thrombin-antithrombin (TAT) complexes, and D-dimer]. Surrogate biomarkers of hemolysis [lactate dehydrogenase (LDH), reticulocyte count, hemoglobin, and % phosphatidylserine-positive-RBCs]; inflammation [high sensitivity C-reactive protein (hs-CRP), white blood cell (WBC), neutrophil and monocyte counts]; and endothelial activation (soluble VCAM-1, E-selectin, and P-selectin) were assessed. Data were analyzed using Spearman correlation and multiple regression models. While correlations were observed in univariate analyses between WBTF and markers of hemolysis, inflammation, and endothelial activation (p<0.01 to <0.00001), the hemolytic marker LDH was the only biomarker that stayed in the regression models (significant contribution of 42%). In similar regression analysis with TAT as the dependent variable, the only biomarkers that stayed in the models were WBC and hs-CRP contributing 29% and 9%, respectively to the overall association. Using D-dimer as the dependent variable, reticulocyte count was the only independent variable that stayed in the regression models (43% contribution). Significant correlations were noted between early and late stage hemostatic markers, i.e. between WBTF and TAT (p<0.05), between WBTF and D-dimer (p=0.005) and between TAT and D-dimer (p=0.006). There were no correlations between MPTF and the other markers of hemostatic activation or with the markers of hemolysis, inflammation or endothelial activation. In addition, we noted that fetal hemoglobin did not provide any protection against hemostatic activation. A previous study from our laboratory has demonstrated that heme, a product of intravascular hemolysis, upregulated endothelial expression of TF mRNA, protein and procoagulant activity in vitro (J Thromb Haemost 2008; 6:2202). Our present findings provide further evidence that intravascular hemolysis (LDH and reticulocyte count), and inflammation (WBC and hs-CRP) play a crucial role in SCD-related hemostatic activation. In addition, our results also suggest that cell-associated TF, rather than microparticle-associated TF, contributes to laboratory evidence of hemostatic activation in subjects with SCD. Disclosures:Setty:NIH: Research Funding. Krishnan:NIH: Research Funding. Gayen-Betal:NIH: Research Funding. Stuart:NIH: Research Funding.

Activated Clotting Times, Heparin Responses, and Antithrombin

Activated Clotting Times, Heparin Responses, and Antithrombin

D-dimer levels and stroke progression in patients with acute ischemic stroke and atrial fibrillation

Patients with acute ischemic stroke and atrial fibrillation are at increased risk of stroke progression and recurrence. We sought to assess whether D-dimer and other markers of hemostatic activation could predict these adverse events in such patients. Blood samples were obtained from patients included in the Heparin in Acute Embolic Stroke Trial. Stroke progression was defined as a ≥3-point worsening on the Scandinavian Stroke Scale during the first 48 h after randomization. Blood samples were analyzed for D-dimer, prothrombin fragment 1 + 2, soluble fibrin monomer, and C-reactive protein. A total of 382 patients were included in the analyses. Levels of D-dimer and other markers of hemostatic activation were not significantly higher in patients with stroke progression than in other patients (D-dimer median values: 1025 ng/ml vs 970 ng/ml, P = 0.73). The same was true for recurrent stroke (D-dimer: 720 ng/ml vs 973 ng/ml, P = 0.96), and the combined endpoint of stroke progression, recurrent stroke, and death (D-dimer: 991 ng/ml vs 970 ng/ml, P = 0.91). Multivariable analyses did not alter the results. D-dimer and other markers of hemostatic activation were not associated with stroke progression, recurrent stroke, or death in patients with acute ischemic stroke and atrial fibrillation.

Eculizumab Therapy Results in Rapid and Sustained Decreases in Markers of Thrombin Generation and Inflammation in Patients with PNH

Paroxysmal Nocturnal Hemoglobinuria (PNH) is a clonal disorder of the bone marrow resulting from an acquired mutation in the PIG-A gene. The mutation decreases production of the glycosylphosphatidylinositol membrane anchor for a variety of membrane proteins. Loss of cell membrane CD59 and CD55 results in enhanced complement-mediated cell membrane injury. PNH is associated with an increased risk of venous (VTE) and arterial thrombosis. Eculizumab, a monoclonal antibody to complement C5, has received FDA approval for the treatment of PNH. Recent published data demonstrates a 92% reduction in thrombotic events with the use of eculizumab. However, the mechanism for this reduction is unclear. We have enrolled eight PNH patients (pts) in an ongoing IRB-approved study on the effect of eculizumab treatment on markers of thrombin generation and inflammation. Patients were treated by the FDA-approved treatment protocol with blood samples obtained prior to treatment day 1 and prior to each dose on days 8, 15, 22, 29, 43 and 90. Patients receiving anticoagulants and corticosteroids were continued on their baseline medications. Plasma samples were assayed for D-dimers (D-D), thrombin-antithrombin complex (TAT), interleukin 6 (Il-6) by ELISA and tissue factor microparticles (TFMP) by impedance-based flow cytometry. Mean age of pts was 40.8 years (26–70); 6 male pts and 2 females. One patient had a prior history of VTE; 4 pts were receiving anticoagulants (1 full dose low molecular weight heparin (LMWH), 2 prophylactic LMWH, 1 warfarin) and 2 pts were receiving prednisone at the initiation of eculizumab. The effect of eculizumab on markers of hemostatic activation and inflammation was evaluated using Wilcoxon signed-rank test and multilevel models.Results: Pretreatment levels of D-D were significantly elevated in all but two of the patients who were receiving anticoagulants. Pretreatment Il-6 levels were significantly elevated in all but two patients taking prednisone. With eculizumab treatment, there was a statistically significant decrease in LDH (p=0.0001), D-D (p=0.0057), TAT (0.0138) and Il-6 (p=0.0362) during the 4 week induction phase of treatment (days 1–29). TAT levels significantly decreased by day 8 (p=0.008), with little subsequent change to day29 and day 90. All decreases in D-D, TAT, Il-6 and LDH were sustained in the maintenance phase of treatment (days29–90). Plasma TFMP were detectable and significantly increased in all patients prior to treatment. There was a statistically significant decrease in TFMP by day 8 (p=0.0234) and TFMP levels remained below pretreatment levels for the duration of the study (p=0.030). However, there were wide individual variations in TFMP levels over the course of treatment. There were significant Spearman correlations between changes in D-D and TAT (0.521; p<0.0001), in D-D and IL-6 (0.4400; p=0.0007). Changes in LDH did not correlate with changes in D-D, TAT, TFMP or Il-6. Changes in TFMP did not correlate with changes in markers of thrombin generation (TAT or D-D).Conclusion: Eculizumab treatment of patients with PNH results in a rapid decrease in plasma tissue factor microparticles, thrombin generation and inflammation. These changes appear to be independent of eculizumab suppression of RBC hemolysis as characterized by decreases in serum LDH. A direct relationship between plasma TFMP levels and thrombin generation in PNH patients could not be confirmed in this study. Taken together, these data indicate the broader impact of eculizumab treatment to suppress inflammation and prothrombotic activity in patients with PNH.

Impact of neutrophil apoptosis on haemostatic activation in chronic liver disease patients

Recent studies suggest the impact of apoptosis on the mechanisms leading to hypercoagulability. We aimed to clarify the potential role of neutrophil apoptosis in neutropenia and hypercoagulable state encountered in chronic liver disease patients. This study was conducted on 15 normal controls and 45 patients with chronic liver disease classified according to modified Child Pugh classification into, Child A, B and C groups (15 cases each). Haemostatic parameters studied include, prothrombin time, partial thromboplastin time, tissue factor, protein C antigen, protein S antigen, and markers of haemostatic activation [prothrombin fragment 1+2 (F1+2), thrombus precursor protein (TpP) and D-dimer]. Flowcytometric study was done for quantitative assay of neutrophil apoptotic subpopulations to detect the percentage of early and late apoptotic, and necrotic neutrophils using Annexin V-FITC/propidium iodide dye. Semiquantitative assay of apoptotic neutrophils showing DNA fragmentation was performed on neutrophil culture using terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling test. In addition to enzyme-linked immunosorbent assay for soluble Fas (APO-1/CD95) in culture supernatant. The results revealed a rise in the neutrophil apoptotic and necrotic markers with progression of the disease, and they were inversely correlated with the absolute neutrophil count. The apoptotic neutrophil cells showed a significant positive correlation with several haemostatic parameters (tissue factor, prothrombin fragment 1+2, thrombus precursor protein and D-dimer). Regression analysis proved that apoptotic parameters are independent determinants of prothrombotic markers, which further incriminate the apoptotic mechanisms in the hypercoagulable state encountered in this clinical setting.

A Comparison of Heparin Management Strategies in Infants Undergoing Cardiopulmonary Bypass

Recent investigations in adult patients have suggested that a heparin concentration-based anticoagulation protocol for heparin administration during cardiopulmonary bypass (CPB) significantly reduced hemostatic activation when compared with standard weight-based heparin doses. Reductions in hemostatic activation during CPB could be particularly beneficial in pediatric patients in whom CPB-related coagulation issues are complex and influenced by many variables. However, information regarding heparin levels during CPB and their correlation to hemostatic activation is lacking in children. In this investigation, we compared a patient-specific heparin concentration-based heparin management protocol with a standard weight-based protocol in infants <6-mo-of-age. The efficacy of these two protocols was assessed by comparisons of heparin concentration, levels of biochemical markers of hemostatic activation, and clinical outcome. Twenty-five infants <6-mo-old scheduled for primary, elective repair of a congenital heart defect were enrolled in this study. Patients were randomized to receive either 400 U/kg of heparin (control group) or a patient-specific heparin dose calculated by the Hepcon Hemostasis Management System Plus (Hepcon HMS; Medtronic, Minneapolis, MN; intervention group). Heparin concentrations were compared between the two groups at predetermined intervals. Blood samples for biochemical markers of hemostatic activation were collected before and after CPB, and measurements of clinical outcome were recorded. Infants in the intervention group received a larger total heparin dose than infants in the control group. Heparin concentrations after the initial heparin dose and 30 min into CPB were similar between groups; however, at the start of rewarming and at the termination of CPB, infants in the intervention group had significantly higher heparin concentrations than infants in the control group. Infants in the intervention group also generated less F1.2 and consumed less factor VIII than infants in the control group. Clinically, however, infants in the intervention group received one more donor exposure from the administration of blood products post-CPB. A heparin concentration-based heparin management protocol in infants <6-mo-old resulted in higher, more constant heparin concentrations during CPB than a standard weight-based protocol. Furthermore, higher heparin concentrations were associated with greater suppression of hemostatic activation, as measured by less generation of thrombin and less consumption of factor VIII. Our findings demonstrate that use of a patient-specific heparin concentration-based protocol for heparin administration during CPB in infants may attenuate hemostatic activation. However, further research is needed to determine if this protocol has clinically beneficial hemostatic effects.

Haemostatic activation markers in brain injury for mortality prediction: comparison of blood samples from the jugular bulb and central venous line

Haemostatic activation markers in brain injury for mortality prediction: comparison of blood samples from the jugular bulb and central venous line

Plasma tissue factor antigen in localized prostate cancer: Distribution, clinical significance and correlation with haemostatic activation markers

Tissue factor (TF) is involved in cancer growth and metastasis, and haemostatic abnormalities are found in most patients with advanced malignancies, including prostate cancer (PC). Because anti-haemostatic agents are increasingly screened for their potential to prolong survival in tumor patients, a detailed characterization of haemostatic markers in selected cancer subtypes and clinical stages is warranted. In this study, we measured preoperative plasma TF antigen in a large cohort of patients with localized PC and correlated its levels with markers of coagulation and platelet activation, prostate-specific antigen (PSA), and histopathological findings to explore its potential as a prognostic marker in this tumor entity. Out of 140 patients, 19% and 23% had plasma TF antigen levels of <40 pg/ml (low-TF) and >200 pg/ml (high-TF), respectively, which was substantially higher than in 42 healthy male controls. Patients also had low-grade systemic coagulation activation as evidenced by elevated D-dimer, F1 + 2, and PAP plasma levels. Furthermore, similar to sP-selectin and sCD40L antigen, flow cytometric analysis of platelet-derived microparticles in plasma revealed significantly increased numbers in high-TF as compared to low-TF patients and controls. Whereas elevated D-dimer was associated with larger and less differentiated tumors, preoperative plasma TF antigen levels (median [IQR]) were higher in patients with (161 pg/ml [100-236]) than in those without recurrent PC (105 pg/ml [52-182]), as indicated by a serum PSA of >0.1 ng/ml during ambulatory follow-up. In patients with localized PC, preoperative plasma TF antigen levels correlate with platelet activation in vivo and may indicate an increased risk for recurrent disease.

Predictive value of D-dimer plasma levels in response and progressive disease in patients with lung cancer

Patients with cancer may present with one or more circulatory markers of haemostatic activation which may be associated with tumor growth and cancer cell dissemination. In our clinical practice we observed haemostatic abnormalities with or without thrombotic episodes in cancer patients. The aim of the present study was to detect the D-dimer plasma levels in advanced-stage lung cancer patients before, during and after chemotherapy, and to determine whether there is a correlation with response rate, disease recurrence and survival, in order to estimate the possible predictive value of D-dimer plasma levels. Forty-seven/52 patients were evaluable and analysed; 38 patients had non-small-cell lung cancer (NSCLC) and 9 small-cell lung cancer (SCLC) and all were at an advanced stage or inoperable. Two (4.3%) achieved complete response (CR), 17 (36.2%) partial response (PR), and 16 (34%) had progressive disease (PD). We found that 14/19 (73.7%) patients with CR or PR showed a reduction in D-dimer plasma values and 11/16 (68.8%) with PD showed increased values; also, in patients with recurrent disease (12/13, 92.3%), D-dimer plasma levels were increased. All of the above values were statistically significant. D-Dimer plasma levels decrease or increase after response and progressive disease, respectively, and can act as a predictive factor of the evolution of the disease.