Calcium Prevents Enhanced Degradation of Factor VIII in the Condition of Motion.

Background: Hemophilia A and B induce recurrent bleeding episodes, mainly in skeletal muscles and joints that are in intermittent motion. We have previously demonstrated that intermittent motion contributes to increased degradation of factors VIII and IX. Objectives: Given that calcium ions are known to enhance factor VIII-von Willebrand factor (vWF) interaction, the present study has investigated the role of these ions on factors VIII and IX in the condition of motion. Methods: The effects of calcium ions were assessed using purified proteins via Western blot, factor VIII activity, immunocytochemistry, and in Institute of Cancer Research (ICR) mice with no specific genetic background. Results: Calcium was found to prevent degradation of plasma-derived factor VIII but not that of factor IX, during intermittent motion. Calcium levels in the microcirculation of mouse striated muscles were elevated following movement, enabling prevention of factor VIII degradation in normal physiology. Calcium supplementation in drinking water increased factor VIII levels in blood and striated muscles of ICR mice during movement. Conclusions: calcium ions decrease factor VIII degradation in the condition of motion. Further research on the impact of calcium salt oral supplementation on hemophilia patients is warranted.

Tissue factor-heparanase complex: intracellular nonhemostatic effects.

Background: Heparanase, known to be involved in angiogenesis, cancer progression, and inflammation, was shown to form a complex with tissue factor (TF) via its procoagulant domain and to enhance the hemostatic system. Objectives: To reveal a potential role of heparanase procoagulant domain in nonhemostatic effects. Methods: Effects of peptides 16 and 16AC derived from the heparanase procoagulant domain, discovered by our group, were studied using the XTT proliferation assay, western blot analysis, and immunostaining in vitro and a mouse wound-healing model. Results: Procoagulant peptides induced increased proliferation, release of heparanase, and upregulation of heparanase, TF, tissue factor pathway inhibitor (TFPI), and TFPI-2 in U87, T47D, and MCF-7 tumor cell lines and in endothelial cells. These results were reversed by a peptide derived from TFPI-2 that inhibited the heparanse procoagulant domain-TF complex. Thrombin had a similar effect on tumor cell proliferation and heparanase release, although the impact of thrombin on cell proliferation was mediated by the heparanase procoagulant domain. A mouse model of full-thickness skin incision exhibited higher levels of heparanase, TF, TFPI, and TFPI-2 in the healing skin, mainly in the blood vessel wall and lumen in animals injected with the procoagulant peptides compared to controls. The cells transfected to overexpress full-length TF or TF devoid of the cytoplasmic domain demonstrated that the procoagulant domain conveyed intracellular signaling via TF. Conclusion: Heparanase procoagulant domain induces nonhemostatic effects via TF. The finding that TF serves as a receptor to heparanase supports the close direct relation between the hemostatic system and cancer progression.

Effects of anti-Xa activity monitoring on the outcome of high-risk pregnancies treated with a prophylactic dose of low-molecular-weight heparin.

OBJECTIVE: To evaluate if anti-Xa level monitoring and dose adjustment in women using a prophylactic dose of enoxaparin can decrease placenta-mediated pregnancy complications. METHODS: This retrospective observational cohort study included pregnant women receiving enoxaparin prophylaxis, who were followed at the Thrombosis and Hemostasis Outpatient clinic between 2010 and 2017. The dose was adjusted according to enoxaparin anti-Xa levels in the study group or the weight of individuals in the control group. RESULTS: Of 585 women surveyed, 110 met the inclusion criteria; 63 of them were included in the study group and 47 in the control group. Mean starting dose was 46 versus 43 mg (p = .25), mean final dose was 52 mg versus 45 mg (p = .03) and dose adjustment was required in 37% versus 11% (p = .002) in the study and control groups, respectively. Twenty-eight percent of anti-Xa measurements in the second trimester were beneath the prophylactic threshold, compared to 11% and 16% in the first and third trimesters, respectively (p = .02). Labors ended with live birth in 91% versus 94% of cases (p = .5), 85% versus 68% of pregnancies were term (p = .05), 11% versus 23% of newborns were low birth weight (p = .1) and placenta-mediated pregnancy complications were documented in 9% versus 19%, (p = .17) in the study group relative to controls, respectively. CONCLUSIONS: The most prominent decrease in anti-Xa levels was observed in the second trimester. Monitored women had significantly more term deliveries and demonstrated a trend toward higher birth weight and fewer placenta-mediated pregnancy complications. Larger studies are needed to confirm improved pregnancy outcome in monitored women.

Augmented Degradation of Factors VIII and IX in the Intermittent Movement State.

The most common clinical presentation of hemophilia A and hemophilia B is bleeding in large joints and striated muscles. It is unclear why bleeding has a predilection to affect joints and muscles. As muscles and joints are involved in intermittent movement, we explored whether this phenomenon could be associated with an impact on factor VIII and IX levels. Purified proteins and a mouse model were assessed using coagulation assays, Western blot analysis and immuno-staining. Movement caused an increase in thrombin activity and a decrease in factor VIII and factor IX activity. The decrease in factor VIII activity was more significant in the presence of thrombin and during movement. Under movement condition, sodium ions appeared to enhance the activity of thrombin that resulted in decreased factor VIII activity. Unlike factor VIII, the reduction in factor IX levels in the movement condition was thrombin-independent. High factor VIII levels were found to protect factor IX from degradation and vice versa. In mice that were in movement, factor VIII and IX levels decreased in the microcirculation of the muscle tissue compared with other tissues and to the muscle tissue at rest. Movement had no effect on von Willebrand factor levels. Movement induces reduction in factor VIII and IX levels. It enables an increase in the binding of sodium ions to thrombin leading to enhanced thrombin activity and augmented degradation of factor VIII. These data suggest a potential mechanism underlying the tendency of hemophilia patients to bleed in muscles and joints.

An outbreak of severe coagulopathy in northern Israel among users of illicit synthetic cannabinoids adulterated with brodifacoum.

INTRODUCTION: Adulteration of illicit drugs is a well-known phenomenon that may expose consumers to unexpected adverse effects. We report a large outbreak of severe coagulopathy in northern Israel during nine months in 2021-2022 among users of synthetic cannabinoids adulterated with a long-acting anticoagulant, brodifacoum. METHODS: We performed a retrospective cohort study based on data extracted from the Israeli National Poison Information Center database and from electronic medical patient records at three participating hospitals. Confiscated drug samples and blood samples obtained at admission in a subgroup of patients were tested for the presence of long-acting anticoagulants. RESULTS: We identified 98 patients affected by the outbreak. All patients had a prolonged international normalized ratio on admission, and in 69%, the blood was non-coagulating. For patients treated in the three participating centers (n = 72), the presenting complaint was overt bleeding in 79% of patients, most commonly in the urinary (53%) and gastrointestinal tracts (50%). The most severe complications were intracranial bleeding (4%), hemothorax (3%), pericardial bleeding (1%), and four patients died. Brodifacoum was detected in all available blood samples (median concentration 207 µg/L, interquartile range 112-349 µg/L, range 45-1,118 µg/L), and the drug samples contained both brodifacoum and the synthetic cannabinoid ADB-BUTINACA. All patients were treated with high-dose phytomenadione (vitamin K1) and additionally by packed red blood cell transfusions, fresh frozen plasma, and/or 4-factor prothrombin complex concentrate when indicated. The most frequent phytomenadione (vitamin K1) dose regimen was initially 20 mg intravenously every eight hours, and at discharge, 20 mg orally three times daily. CONCLUSIONS: Outbreaks of severe coagulopathies in users of synthetic cannabinoids adulterated with a long-acting anticoagulant continue to erupt in different regions of the world. Rapid recognition of an outbreak requires a high index of suspicion when confronting young, otherwise healthy subjects with otherwise unexplained severe coagulopathy.

Effect of Heparanase and Heparan Sulfate Chains in Hemostasis.

Heparanase, the only mammalian enzyme known to degrade heparan sulfate chains, affects the hemostatic system through several mechanisms. Along with the degrading effect, heparanase engenders release of syndecan-1 from the cell surface and directly enhances the activity of the blood coagulation initiator, tissue factor, in the coagulation system. Upregulation of tissue factor and release of tissue factor pathway inhibitor from the cell surface contribute to the prothrombotic effect. Tissue factor pathway inhibitor and the strongest physiological anticoagulant antithrombin are attached to the endothelial cell surface by heparan sulfate. Hence, degradation of heparan sulfate induces further release of these two natural anticoagulants from endothelial cells. Elevated heparanase procoagulant activity and heparan sulfate chain levels in plasma, demonstrated in cancer, pregnancy, oral contraceptive use, and aging, could suggest a potential mechanism for increased risk of thrombosis in these clinical settings. In contrast to the blood circulation, accumulation of heparan sulfate chains in transudate and exudate pleural effusions induces a local anticoagulant milieu. The anticoagulant effect of heparan sulfate chains in other closed spaces such as peritoneal or subdural cavities should be further investigated.

Pregnancy and non-pregnancy related immune thrombotic thrombocytopenic purpura in women of reproductive age.

Pregnancy is a precipitating factor for immune thrombotic thrombocytopenic purpura (iTTP). We compared the clinical course and outcomes of iTTP in women of reproductive age, between those with pregnancy- and non-pregnancy-related iTTP. A review of all reproductive-aged women diagnosed with iTTP during 2010-2019 in seven university hospitals in Israel. Of 42 cases of iTTP, 12 (28.6%) were pregnancy-related. At presentation, the laboratory profiles did not differ significantly between those with pregnancy- and non-pregnancy-related iTTP, including hemoglobin (median 8.4 vs 8.0 g/dL), platelet count (12.5 vs. 11.5 X 109/L); and levels of bilirubin (1.23 vs. 1.82 mg/dL), lactate dehydrogenase (1615 vs. 1701 U/L), creatinine (0.61 vs. 0.79 mg/dL) and anti-ADAMTS13 antibodies titer (75 vs. 82 U/mL). The proportions of women with renal, neurologic, or hepatic involvement were similar between the groups. Cardiac involvement was more common among those with pregnancy-related disease (25.0% vs. 3.3%, P = 0.06). The median number of courses of plasma-exchange therapy was 11 for both groups. All the women were treated with parenteral corticosteroids and the rate of adjunctive treatments did not differ between the groups (P = 0.30). Four women (one-third) with pregnancy-related disease had preeclampsia. Two women (16.7%) with pregnancy-related iTTP died during the acute episode (P = 0.07); no deaths were observed in the non-pregnancy-related group. Among reproductive-aged women with iTTP, most clinical and laboratory profiles were similar between those with pregnancy- and non-pregnancy-related disease. However, the higher rates of cardiac involvement and mortality among women with pregnancy-related iTTP highlight its challenging management.

Progestin type affects the increase of heparanase level and procoagulant activity mediated by the estrogen receptor.

STUDY QUESTION: Does progestin have an effect on heparanase level and procoagulant activity? SUMMARY ANSWER: Progestin increases the heparanase level and procoagulant activity via the estrogen receptor and the magnitude of the effect depends on the progestin type. WHAT IS KNOWN ALREADY: Users of combined oral contraceptives (COCs) containing third- and fourth-generation progestins have a higher risk of venous thrombosis compared to those employing second-generation progestins. Heparanase protein is capable of degrading heparan sulfate (HS) chains and enhancing activation of the coagulation system. We have previously demonstrated that estrogen enhances the expression and procoagulant activity of heparanase. STUDY DESIGN, SIZE, DURATION: Estrogen and progestin receptor positive breast carcinoma cell lines: EMT6, T47D and MCF-7 were compared to the MDA-231 breast carcinoma cell line devoid of these receptors. This observational study incorporated 45 users of third-generation COCs progestins, 21 users of fourth-generation COCs progestins and 28 individuals not using hormonal therapy and not pregnant per history. PARTICIPANTS/MATERIALS, SETTING, METHODS: Second-generation progestin-levonorgestrel, third-generation progestin-desogastrel (DSG), an estrogen receptor antagonist-ICI 182.780 and a progestin receptor antagonist-mifepristone, were added to cell lines. Heparanase level and procoagulant activity, HS levels, tissue factor (TF) activity and factor Xa levels were evaluated in the plasma of the study group. MAIN RESULTS AND THE ROLE OF CHANCE: Levonorgestrel and DSG increased heparanase levels in the cells and medium. The effect of DSG was more prominent and additive to that of estrogen. The effect was inhibited by ICI 182.780. In the plasma of COC users, heparanase procoagulant activity, HS levels, TF activity and factor Xa levels were significantly higher compared to controls. In COC pills containing the same dose of estrogen, the procoagulant effect of drospirenone was significantly stronger than that of DSG and gestodene. LIMITATIONS, REASONS FOR CAUTION: The limitations of the study include a small number of participants in each study group, although the results are statistically significant and evaluated by several different coagulation parameters. WIDER IMPLICATIONS OF THE FINDINGS: The study demonstrates a new mechanism through which progestin affects coagulation system activation and shows that this effect is progestin type-dependent. Development of a progestin derivative with an attenuated effect on heparanase procoagulant activity may reduce thrombotic risk. STUDY FUNDING/COMPETING INTEREST(S): No external funding was sought for this study. Y.N. is named in a European patent application No. IL201200027 filed on 18 January 2012. Other authors have no conflict of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Heparanase Level and Procoagulant Activity Are Increased in Thalassemia and Attenuated by Janus Kinase 2 Inhibition.

Patients with thalassemia exhibit an increased risk of thrombotic events that is augmented after splenectomy. Heparanase protein enhances cancer progression, angiogenesis, and inflammation; it also activates the coagulation system through direct interaction with tissue factor (TF). Additionally, erythropoietin, which is elevated in anemic patients, up-regulates heparanase expression via the Janus kinase 2 (JAK-2) pathway. This study aimed was to explore the heparanase profile in thalassemia. Coagulation factors were analyzed via immunostaining, enzyme-linked immunosorbent assay, and heparanase procoagulant activity assay. In spleen specimens of thalassemia major patients, a higher level of heparanase staining was observed compared with control spleens resected after trauma (P < 0.001). Higher heparanase levels, heparanase and TF procoagulant activity, and erythropoietin levels were found in the plasma of 67 thalassemia major patients compared with 29 control subjects. No difference was found in pediatric patients (23 of 67) compared with adults or splenectomized versus nonsplenectomized patients. Higher levels of heparanase, TF, TF pathway inhibitor, and TF pathway inhibitor-2 were observed in liver, spleen, heart, and kidney tissues of thalassemia intermedia mice (Hbbth3/+). These protein levels significantly reduced when mice were treated with the JAK-2 inhibitor ruxolitinib (P < 0.0001). In summary, heparanase levels are elevated in thalassemia, which may contribute to thrombotic phenomena in these patients. Inhibition of heparanase or the JAK-2 pathway may reduce thrombotic risk in thalassemia.

Circulating heparan sulfate chains and body weight contribute to anti-Xa levels in cancer patients using the prophylactic dose of enoxaparin.

Hospitalized cancer patients are at increased risk of thrombosis and prophylaxis with heparin is recommended. Heparanase is a protein capable of degrading heparan sulfate (HS) chains. The first objective of the study was to examine the effects of weight on anti-Xa levels in cancer patients treated with a fixed dose of enoxaparin as thromboprophylaxis. The second aim was to assess a potential correlation between plasma pre-treatment coagulation parameters and anti-Xa levels in an assumption that heparanase degradation activity towards heparins and HS chains could affect anti-Xa levels. Two blood samples (prior to and 3 h after drug injection) of 76 cancer patients with an indication for prophylaxis with enoxaparin (40 mg) were evaluated for coagulation markers. Sub-prophylactic levels of anti-Xa (< 0.2 U/ml) were found in 16/76 (21%) patients; in 13/76 (13%) patients the values were supra-prophylactic (> 0.5 U/ml). In the subgroup of patients weighing > 80 kg, 7/14 (50%) individuals had a sub-prophylactic level. Overall, anti-Xa levels appeared to correlate with patient's weight (r = - 0.48, p < 0.0001), pre-treatment partial thromboplastin time (PTT), D-dimer, HS, heparanase levels and procoagulant activity. We concluded that plasma anti-Xa levels correlated with patient's weight. A substantial portion of cancer patients receiving enoxaparin prophylaxis was undertreated. For patients > 80 kg, a weight-adjusted prophylactic dose of enoxaparin could be considered. Elevated enoxaparin anti-Xa levels correlated with pre-treatment parameters of coagulation system activation. High pre-treatment HS and elevated plasma anti-Xa levels may potentially serve as biomarkers for the identification of patients at increased thrombosis risk.

Heparanase in the Coagulation System.

The hemostatic cascade is initiated by the transmembrane coagulation protein - tissue factor (TF) and eventuates in fibrin formation. Heparanase protein was demonstrated to directly enhance TF activity resulting in increased activation of the coagulation system. In addition, heparanase was found to increase hemostatic system activation via two other mechanisms: up-regulating TF expression in endothelial cells and releasing the protein tissue factor pathway inhibitor (TFPI) from the cell surface. Peptides derived from TFPI-2, a protein similar to TFPI, were shown to inhibit the TF/heparanase complex as well as attenuate sepsis and tumor growth. Increased heparanase procoagulant activity was observed in several clinical settings, including women using oral contraceptives, women at delivery, patients following orthopedic surgery and patients with diabetic foot, shift work female nurses, patients with lung cancer, retinal vein thrombosis and prosthetic heart valve thrombosis. Remarkably, the heparanase profile was significantly different across the tested groups. Inhibition of TF / heparanase interaction may represent a new target for attenuating coagulation, cancer and inflammation.

Heparan sulfate chains contribute to the anticoagulant milieu in malignant pleural effusion.

BACKGROUND: While malignant pleural effusion (MPE) is a common and significant cause of morbidity in patients with cancer, current treatment options are limited. Human heparanase, involved in angiogenesis and metastasis, cleaves heparan sulfate (HS) side chains on the cell surface. AIMS: To explore the coagulation milieu in MPE and infectious pleural effusion (IPE) focusing on the involvement of heparanase. METHODS: Samples of 30 patients with MPE and 44 patients with IPE were evaluated in comparison to those of 33 patients with transudate pleural effusions, using heparanase ELISA, heparanase procoagulant activity assay, thrombin and factor Xa chromogenic assays and thromboelastography. A cell proliferation assay was performed. EMT-6 breast cancer cells were injected to the pleural cavity of mice. A peptide inhibiting heparanase activity was administered subcutaneously. RESULTS: Levels of heparanase, factor Xa and thrombin were significantly higher in exudate than transudate. Thromboelastography detected almost no thrombus formation in the whole blood, mainly on MPE addition. This effect was completely reversed by bacterial heparinase. Direct measurement revealed high levels of HS chains in pleural effusions. Higher proliferation was observed in tumour cell lines incubated with exudate than with transudate and it was reduced when bacterial heparinase was added. The tumour size in the pleural cavity of mice treated with the heparanase inhibitor were significantly smaller compared with control (p=0.005). CONCLUSIONS: HS chains released by heparanase form an anticoagulant milieu in MPE, preventing local thrombosis and enabling tumour cell proliferation. Inhibition of heparanase might provide a therapeutic option for patients with recurrent MPE.

Decreasing Tumor Growth and Angiogenesis by Inhibition of Coagulation.

Data regarding the effect of coagulation proteins on enhancing angiogenesis and tumor growth are ample. Thus, inhibition of the coagulation system in an attempt to reduce tumor growth and metastasis seems appealing. However, such molecules as direct oral anticoagulants, warfarin and heparins, may impose a bleeding tendency, limiting the treatment dose that can be used. The heparanase protein, as a cofactor for tissue factor (TF) activity, enhances activation of the coagulation system and in addition has several nonhemostatic effects increasing tumor growth. The molecules currently investigated in the field of cancer and coagulation are heparin mimetics and inhibitors of heparanase derived from TF pathway inhibitor 2. Both groups of molecules are inhibitors of heparanase and in addition pose a low bleeding tendency. Hence, interfering in heparanase activity seems to be a promising target for development of antitumor drugs.

Heparanase Level in the Microcirculation as a Possible Modulator of the Metastatic Process.

Metastasis most commonly occurs in the liver, lung, bone, and brain, implying its preference for specific organs. We hypothesized that organ microcirculation coagulation environment predisposes to tumor cell retention. Coagulation factors were analyzed using immunostaining, enzyme-linked immunosorbent assay, and heparanase procoagulant activity assay. In normal mice, expression levels of heparanase, tissue factor (TF), TF pathway inhibitor (TFPI), and TFPI-2 were low in the microcirculation of the liver, lung, brain cortex, and bone, and high in the microcirculation of the subcutis, skeletal muscle, brain subcortex, and bone marrow. C57BL/6 mice injected s.c. with B16 (F10) melanoma cells demonstrated lower levels of heparanase, TF, TFPI, and TFPI-2 in metastasis blood vessels compared to those in the primary tumor. In these mice with metastasis, liver and lung microcirculation turned to express high levels of coagulation proteins. Additionally, although mice with heparanase overexpression developed a larger primary tumor, they did not demonstrate a tendency for metastasis, as opposed to controls (P < 0.0001). Human umbilical vein endothelial cells, incubated with the B16 melanoma cell medium for 2 hours, expressed decreased levels of heparanase, TF, TFPI, and TFPI-2, and the effect was reversed by a peptide-inhibiting heparanase/TF complex interaction (P < 0.001). In summary, metastasis has a predilection to organs with low levels of heparanase, TF, TFPI, and TFPI-2 in the microcirculation, which enables tumor cell retention. Heparanase has a role in regulating the microcirculation milieu.

[COAGULATION - A PHYSIOLOGICAL SYSTEM INTERFACING ALL OTHER BODY SYSTEMS].

INTRODUCTION: The coagulation system is a rapidly advancing area of clinical and basic research. Among the critical clinical issues to be urgently addressed are those related to the application of new direct oral anticoagulants in real life. Extensive research in the challenging field of thrombosis and bleeding is ongoing and has already resulted in new pharmacological modalities such as siRNA. The well-established close association between coagulation and cancer provides a strong incentive for developing drugs capable of interfering with the coagulation system and attenuating tumor growth. The multifaceted research field in coagulation requires dedicating specialized personnel in the hospitals along with bridging staff mediating between the hospital and the outpatient clinics to ensure proper patient management.

[ACQUIRED HEMOPHILIA A AND THE TIMING OF IMMUNOMODULATORY THERAPY].

INTRODUCTION: Acquired hemophilia A is an autoimmune disease affecting men and women equally and is idiopathic in 50% of the cases. As the mortality rate reaches 50%, prompt diagnosis and treatment are needed. Diagnosis is made in a patient with a bleeding manifestation and prolonged PTT (partial thromboplastin time) that is not corrected in a mixing study with normal plasma. The level of antibodies in the plasma is measured by Bethesda units and a level above 5 units is considered high. Patients with a high titer of antibodies are treated with factor VIII, prothrombin complex, recombinant factor VIIa and tranexamic acid, in combination with immunomodulatory therapy, including steroids, cyclophosphamide, rituximab and immunoglobulins. The timing of rituximab therapy remains debatable. To date, it has not been established whether to use it as a first-line or second-line therapy. According to the currently available literature that relies on a database, the use of rituximab as a first-line modality increased survival without increasing the rate of infections, compared to steroids alone or steroids combined with cyclophosphamide. The current article describes a 79-year old woman who presented with diffuse hematomas in the limbs. A rapid diagnosis and treatment, including factor VIII, tranexamic acid, steroids, cyclophosphamide and rituximab as a first-line therapy, facilitated her complete recovery at a one-year follow-up.

[EXPERIENCE IN DIAGNOSTIC ASSAYS FOR HEPARIN-INDUCED THROMBOCYTOPENIA - EXPERIENCE OF A TERTIARY HOSPITAL IN ISRAEL].

AIMS: To analyze the experience of a tertiary medical center in clinical and laboratory diagnosis of suspected HIT. BACKGROUND: The diagnosis of heparin-induced thrombocytopenia (HIT) requires clinical data and laboratory detection of platelet activating factor 4/heparin (PF4/H) antibodies by immunological or functional assays. Although antigen screening assays are widely used, the functional assays are performed only by several expert labs. METHODS: A retrospective review of the Hematology Laboratory database on patients evaluated between the years 2008-2016 at Rambam, identified 412 individuals with clinical suspicion of HIT. Till 2011, 135 cases were screened using particle gel PaGIA (Biorad) and between the years 2012-2016, a total of 277 cases were screened by lateral flow Milenia (Biotec GmbH). All patients diagnosed with HIT were treated with Fondaparinux (Arixtra). Functional assay with heparin/LMWH induced platelet aggregation was performed using light transmission aggregometry (Helena AggRAM) to validate borderline or positive results in indistinct cases. RESULTS: From the tested samples, 63% vs. 75% were negative in PaGIA and Milenia, respectively (P=0.03), and were considered negative for HIT. During 2008-2011, only 38% of cases with non-negative immunoassay results underwent functional aggregation, whereas, in 2012-2016, 83% of such cases were further evaluated. None of the borderline PaGIA samples was positive in the functional assay compared to 13.3% borderline Milenia results; 25% of positive PaGIA and 51.7% of positive Milenia were confirmed by a positive functional HIT assay (P=N.S.). The survival rate among 14 patients with a positive functional assay was 42.7 % (6 patients). CONCLUSIONS: The Milenia assay introduced at our lab in 2012, has improved the screening process. The functional assay provides a more accurate HIT diagnosis. The combined approach of an optimal laboratory and clinical investigation is crucial to obtain a precise HIT diagnosis.

Cancer and Thrombosis-New Insights.

Cancer patients have a pro-thrombotic state attributed to the ability of cancer cells to activate the coagulation system and interact with hemostatic cells, thus tilting the balance between pro- and anticoagulants. Mechanisms underlying the coagulation system activation involve tumor cells, endothelial cells, platelets, and white blood cells. Anti-cancer therapies, including anti-angiogenic drugs, significantly increase the risk of thrombosis during treatment. Along with the role of coagulation proteins in the hemostatic system, these proteins also serve as growth factors to the tumor. Heparanase is a pro-angiogenic and pro-metastatic protein. Our previous studies have demonstrated that it enhances tissue factor (TF) activity and is present at high levels in tumor cells and patients' blood. Strategies to attenuate heparanase effects by heparin mimetics or peptides interrupting the TF-heparanase interaction are good candidates to attenuate tumor growth and thrombotic manifestations.