The production of coagulation factor VII by adipocytes is enhanced by tumor necrosis factor-α or isoproterenol.

BACKGROUND: A relationship has been reported between blood concentrations of coagulation factor VII (FVII) and obesity. In addition to its role in coagulation, FVII has been shown to inhibit insulin signals in adipocytes. However, the production of FVII by adipocytes remains unclear. OBJECTIVE: We herein investigated the production and secretion of FVII by adipocytes, especially in relation to obesity-related conditions including adipose inflammation and sympathetic nerve activation. METHODS: C57Bl/6J mice were fed a low- or high-fat diet and the expression of FVII messenger RNA (mRNA) was then examined in adipose tissue. 3T3-L1 cells were used as an adipocyte model for in vitro experiments in which these cells were treated with tumor necrosis factor-α (TNF-α) or isoproterenol. The expression and secretion of FVII were assessed by quantitative real-time PCR, Western blotting and enzyme-linked immunosorbent assays. RESULTS: The expression of FVII mRNA in the adipose tissue of mice fed with high-fat diet was significantly higher than that in mice fed with low-fat diet. Expression of the FVII gene and protein was induced during adipogenesis and maintained in mature adipocytes. The expression and secretion of FVII mRNA were increased in the culture medium of 3T3-L1 adipocytes treated with TNF-α, and these effects were blocked when these cells were exposed to inhibitors of mitogen-activated kinases or NF-κB activation. The ß-adrenoceptor agonist isoproterenol stimulated the secretion of FVII from mature adipocytes via the cyclic AMP/protein kinase A pathway. Blockade of secreted FVII with the anti-FVII antibody did not affect the phosphorylation of Akt in the isoproterenol-stimulated adipocytes. CONCLUSION: Obese adipose tissue produced FVII. The production and secretion of FVII by adipocytes was enhanced by TNF-α or isoproterenol via different mechanisms. These results indicate that FVII is an adipokine that plays an important role in the pathogenesis of obesity.

APTT reagent with ellagic acid as activator shows adequate lupus anticoagulant sensitivity in comparison to silica-based reagent.

BACKGROUND: Lupus anticoagulant (LA) is an antibody that interferes with phospholipid-dependent coagulation reactions. Activated partial thromboplastin time (APTT) is widely used as a test for LA screening. APTT reagents are composed of activators, such as silica or ellagic acid, and phospholipids, and APTT reagents with silica are recommended for LA screening because of greater sensitivity. However, the effects of activators on LA activity have not been adequately investigated. OBJECTIVES: In this study, we examined whether an ellagic acid-based reagent was highly sensitive to LA in a low phospholipid condition and useful for LA screening. METHODS: Silica-based (SL) and ellagic acid-based (EA) reagents were prepared in-house with the same composition and concentration of phospholipids, while the commercial APTT reagents APTT-SLA (SLA), Actin FSL (FSL), APTT-SP (SP) and PTT-LA (PTT) were also included in the study. RESULTS: The normal reference ranges for SL and EA were 30.1-47.0 and 28.0-40.2 s, respectively, while the cut-off index values for circulating anticoagulant activity (ICA) calculated from the results obtained with SL, EA, SLA, FSL, SP and PTT were 12.9, 11.5, 13.2, 15.6, 14.3 and 14.0, respectively. The sensitivity of those reagents based on those cut-off values was 91%, 96%, 68%, 46%, 91% and 86%, respectively. CONCLUSIONS: Our results showed that the ellagic acid-based reagent was more sensitive to LA than silica-based reagents in a low phospholipid condition and had adequate sensitivity to detect LA. We concluded that the sensitivity of APTT reagents for LA is dependent on phospholipid concentration and not the activator.

Trousseau's syndrome associated with tissue factor produced by pulmonary adenocarcinoma.

The case history is presented of a patient with Trousseau's syndrome in which tissue factor originating from lung cancer appeared responsible for recurrent DVT/PE. This is thought to be the first such case to be reported.

Synthetic selective inhibitors of coagulation factor Xa strongly inhibit thrombin generation without affecting initial thrombin forming time necessary for platelet activation in hemostasis.

DX-9065a and JTV-803, synthetic selective inhibitors of activated factor X (FXa), have recently been demonstrated as strongly effective antithrombotic agents in animal thrombosis models, yet with a low risk of bleeding. The aim of the present study was to elucidate these characteristics. Using a chromogenic assay with purified coagulation factors, 73.9% of thrombin generation was suppressed by the addition of DX-9065a (0.20 microm) and 75.7% by JTV-803 (0.18 microm). Inhibition by argatroban (0.19 microm) was less (36.0%) and initial thrombin forming time (T50), the time required to generate 50% thrombin activity in vitro, which is considered important for platelet aggregation in hemostasis, was significantly prolonged by argatroban. In contrast, DX-9065a and JTV-803 had no apparent influence on T50, suggesting that initial thrombin was formed immediately, as in the control. We also investigated platelet aggregation in defibrinated plasma induced by tissue factor, to clarify whether initial thrombin contributes to hemostasis. Aggregation was not affected by the addition of either FXa inhibitor, whereas it was significantly reduced by argatroban. Our results suggest that initial thrombin, which is formed despite the presence of a FXa inhibitor, can activate platelets. We concluded that DX-9065a and JTV-803 are able to inhibit thrombin generation significantly without affecting the formation of initial thrombin for platelet activation, which may contribute to hemostasis through the preservation of normal bleeding time.

The inhibition of protein C anticoagulant activity by anti-ß2-glycoprotein I (ß2GPI) antibodies isolated from patients with antiphospholipid syndrome by chromatography methods.

Abstract Antiphospholipid antibodies (aPL) are associated with an increased risk of thrombosis; however, the mechanism remains unknown. Recent studies have focused on the impediment of protein C anticoagulant activity by anti-ß2-glycoprotein I (ß2GPI) antibodies (aß2GPI Ab). We purified IgG fractions containing a high concentration of aß2GPI Ab from patients with antiphospholipid syndrome (APS) and then investigated the effect of purified aß2GPI Ab on the activity of activated protein C (APC). Using a three-step chromatography method (DEAE-sepharose column, phosphatidylserine polyacrylamide gel column dependent on the presence of ß2GPI, and protein G column chromatography), we successfully isolated anti-ß2GPI IgG from nine patients with APS. Seven of nine samples inhibited APC activity in a concentration-dependent manner only in the presence of ß2GPI, as observed by a chromogenic assay that was able to determine thrombin activity even in the presence of APC. The extent of APC inhibition by these fractions appeared to be related to aß2GPI Ab titers of the purified IgG. However, the inhibitory effect of IgG from patients was not detected in the absence of ß2GPI. IgG purified from three normal subjects did not affect APC activity. Herein, we show a useful method for the isolation of IgG containing a high concentration of aß2GPI Ab. Moreover, the present findings indicate that inhibition by aß2GPI Ab on APC anticoagulant activity could explain one of the mechanisms for the thrombotic state in APS.

Association of autoantibodies against the phosphatidylserine-prothrombin complex with manifestations of the antiphospholipid syndrome and with the presence of lupus anticoagulant.

OBJECTIVE: To clarify the association of autoantibodies against prothrombin with the clinical manifestations of the antiphospholipid syndrome (APS) and with the presence of lupus anticoagulant (LAC). METHODS: We examined 265 patients who visited our autoimmune disease clinic. IgG and IgM antiprothrombin antibodies were tested by enzyme-linked immunosorbent assay (ELISA) as either antiphosphatidylserine-prothrombin complex (aPS/PT) antibodies or as antibodies against prothrombin coated on irradiated ELISA plates (as antigen) (aPT). IgG, IgM, and IgA anticardiolipin (aCL) antibodies and their beta2-glycoprotein I (beta2GPI) dependency were also evaluated by ELISA. LAC was tested by 3 different methods. RESULTS: The presence of aPS/PT, but not of aPT, significantly correlated with the clinical manifestations of APS (odds ratio [OR] 4.39, 95% confidence interval [95% CI] 2.06-9.38), and aPS/PT antibodies were as specific as beta2GPI-dependent aCL for APS (93.1% for both). IgG aPS/PT strongly correlated with the presence of LAC as detected using the dilute Russell viper venom time test (OR 38.2, 95% CI 13.4-109.1). CONCLUSION: Antiprothrombin antibodies are heterogeneous and their clinical relevance depends on the method of detection applied. Positive results on the aPS/PT test can serve as a marker of thrombotic events in patients with autoimmune diseases.

Coagulation and fibrinolytic activities in 2 siblings with beta(2)-glycoprotein I deficiency.

beta(2)-Glycoprotein I (beta(2)GPI) is a major antigen for antiphospholipid antibodies, and its multiple in vitro functions have been reported. This glycoprotein not only down-regulates thrombin formation by inhibiting contact activation or prothrombinase activity, but also up-regulates coagulation by reducing protein C anticoagulant activity. However, the in vivo roles of beta(2)GPI remain obscure. Coagulation and fibrinolytic characteristics were investigated in individuals with beta(2)GPI deficiency. An apparently healthy woman and her brother are homozygotes for beta(2)GPI deficiency. In these patients, Russell viper venom time was shortened (40.4 seconds; normal range, 47.8 +/- 4.95 seconds), but all markers of thrombin generation and fibrin turnover were within normal ranges. Exogenous activated protein C adequately prolonged the clotting time of the beta(2)GPI-deficient plasma, and euglobulin lysis time was also normal. Thus, elevated thrombin generation, enhancement of activated protein C response, and an altered fibrinolytic system were not found in congenitally beta(2)GPI-deficient plasma. (Blood. 2000;96:1594-1595)

[Evaluation of F1 + 2/TAT ratios in Japanese patients with antiphospholipid syndrome].

The clinical manifestations of the antiphospholipid syndrome(APS) include arterial and venous thrombosis and a fetal loss, but the pathogenic mechanisms remain unclear. To clarify the mechanism of thrombogenic state in APS, we investigated the markers for thrombosis including thrombin-antithrombin complex(TAT) in patients with antiphospholipid antibodies(aPL). Prothrombin fragment 1 + 2(F1 + 2) in patients with APS and in autoimmune disease patients with aPL increased significantly compared with those obtained in autoimmune disease patients without aPL or in control subjects. However, there was not a significant difference in the TAT level of each group, suggesting that the formation of TAT was impeded in APS. To investigate which aPL is responsible for the disturbance of the TAT formation, the ratio of F1 + 2/TAT was calculated. The ratio increased in patients with lupus anticoagulant, especially with prolonged kaolin clotting time, and furthermore the ratio strongly increased in patients with IgG type-anticardiolipin antibodies(aCL). Our results suggest that IgG-aCL is associated with thrombogenic state in APS because free thrombin is present in patients' blood by impeding the formation of TAT by mainly IgG-aCL.

[Antiphospholipid antibodies and thrombosis: the putative mechanisms of hypercoagulable state in patients with anticardiolipin antibody].

Antiphospholipid antibodies are well recognized as associated with serious clinical complications such as arterial and venous thrombosis and recurrent spontaneous abortion. These complications are collectively called antiphospholipid syndrome(APS). The mechanisms responsible for the thrombosis are unclear. We reported three mechanisms. beta 2-glycoprotein I(beta 2GPI) inhibited activated protein C(APC) activity and, furthermore, APC activity decreased by the addition of monoclonal aCL and beta 2GPI. Monoclonal anticardiolipin antibodies(aCL) seemed to enhance the inhibition of APC procoagulant activity caused by beta 2GPI. Monoclonal aCL in the presence of beta 2GPI also increased the activity of plasminogen activator inhibitor(PAI)-1 in the mixture of tissue-plasminogen activator(t-PA) and PAI-1 by inhibiting the function of beta 2GPI, which increased the remaining t-PA activity in the mixture. The formation of thrombin-antithrombin complexes(TAT) in APS was impaired. The level of TAT in APS did not increase, however the level of prothrombin fragment 1 + 2 (F1 + 2) increased. Therefore, free thrombin present in patients' blood may contribute to thrombosis in APS. These reports indicate that thrombosis in APS may be caused by several thrombogenic factors that stimulate aCL.

Effects of beta2-glycoprotein I and monoclonal anticardiolipin antibodies on extrinsic fibrinolysis.

Antiphospholipid antibodies (aPLs) are associated with an increased incidence of thrombosis, but the mechanisms responsible for thrombosis are unclear. The present study investigated the effect of both beta2-glycoprotein I (beta2-GPI) and aPLs on the activity of extrinsic fibrinolysis. The remaining tissue-plasminogen activator (t-PA) of the sample consisting of beta2-GPI, two-chain recombinant t-PA, plasminogen activator inhibitor (PAI) -1 was measured by a chromogenic assay using synthetic substrate S-2251, Glu-plasminogen, and soluble fibrin monomer. Without PAI-1, beta2-GPI did not affect t-PA activity. When 14.3 ng/ml PAI-1 was added to 3.6 U/ml t-PA, the remaining t-PA activity was increased from 48.9% to 60.4% by the addition of beta2-GPI (190 microg/ml). The effect of beta2-GPI did not require phospholipids. The beta2-GPI seems to protect t-PA activity from the inhibition by PAI-1. When monoclonal anticardiolipin antibodies (aCLs), EY1C8, and EY2C9, which were established from a patient with antiphospholipid syndrome, were further added to the mixture with a diluted phospholipid (Platelin) to investigate the influence of aPL, the remaining t-PA activity decreased to 50.1 and 80.7%. Monoclonal aCLs appeared to inhibit the effect of beta2-GPI, that is, these monoclonals inhibited the fibrinolytic activity by an elevation in PAI-1 activity. These results suggest the possibility that the impairment of fibrinolytic activity by aCLs is one of reasons for the increased incidence in thrombosis in patients with aCLs.

Role of physiologic concentrations of stem cell factor in leukemic type growth of myelodysplastic CD34+ cells.

The stem cell factor (SCF: a ligand for c-kit) plays a central role in the growth of myelodysplastic (MDS) progenitor cells with leukemic type growth. In this study, the role of physiologic concentrations of SCF on the proliferation and differentiation on MDS progenitor cells was further analyzed in the presence of combined cytokines. For this purpose, marrow CD34+ cells were purified up to 94% for 12 normal individuals and 90% for 18 MDS patients, using monoclonal antibodies and immunomagnetic microspheres. The purified CD34+ cells were cultured for 14 days with saturating doses of cytokines, including recombinant human macrophage colony stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte/macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3) and rSCF. The clonal growth of MDS CD34+ cells supported by a combination of all the above cytokines was then subdivided into the two patterns of leukemic or non-leukemic. The role of various concentrations of rSCF (0, 0.5, 5, 50 and 500 ng ml(-1)), with or without the above cytokines, in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. The physiologic concentration of SCF at 5 ng ml(-1) significantly increased undifferentiated 'blast cell' colonies or clusters in leukemic type growth of MDS CD34+ cells over that seen in normal CD34+ cells. SCF is present in plasma at a level of ng ml(-1). This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blasts.

Beta2-glycoprotein I is necessary to inhibit protein C activity by monoclonal anticardiolipin antibodies.

OBJECTIVE: To clarify mechanisms of the thrombosis associated with anticardiolipin antibodies (aCL), we examined the effects on activated protein C (APC) of monoclonal aCL and beta2-glycoprotein I (beta2GPI), which is required for formation of the epitopes of aCL. METHODS: We developed the chromogenic assay, in which the degradation of coagulation factor Va by APC is reflected in the reduced generation of thrombin from prothrombin, using soybean trypsin inhibitor to inhibit APC. APC activities were measured in the presence and absence of 3.4 microM beta2GPI and/or 2.5 microg/ml of IgM monoclonal aCL (EY2C9 and EY1C8) established from peripheral blood lymphocytes obtained from a patient with aCL. RESULTS: Without APC, the formed thrombin activity decreased by the addition of 3.4 microM beta2GPI. When 12.8 nM APC was added, beta2GPI partially reversed the APC-induced inhibition of thrombin generation in a concentration-dependent manner. With 3.4 microM beta2GPI, the thrombin generation in monoclonal aCL (2.5 microg/ml) decreased to 77.1-80.2% by the addition of 12.8 nM APC, but the values were above that in the control IgM (72.7%). Without beta2GPI, the APC activity was unaffected by the addition of monoclonal aCL. CONCLUSION: Beta2-glycoprotein I exhibits procoagulant activity by inhibiting APC activity and anticoagulant activity by inhibiting thrombin generation. Any further inhibition of APC activity was caused by monoclonal aCL and only in the presence of beta2GPI.

The putative mechanism of thrombosis in antiphospholipid syndrome: impairment of the protein C and the fibrinolytic systems by monoclonal anticardiolipin antibodies.

The mechanism of thrombosis in patients with antiphospholipid syndrome is not clear. To investigate it, we examined the effect of monoclonal anticardiolipin (aCL) antibodies and beta2-glycoprotein I (beta2-GPI), which is required for formation of the aCL epitopes, on activated protein C (APC) and on fibrinolytic activity. First, APC activities were measured in the presence and absence of beta2-GPI or gamma M immunoglobulin (IgM) monoclonal aCLs (EY1C8 and EY2C9), or both, established from peripheral blood lymphocytes obtained from a patient with aCL. beta2-GPI exhibited a procoagulant activity by inhibiting APC activity as well as an anticoagulant activity by inhibiting thrombin generation. Any further inhibition of APC activity was caused by monoclonal aCL, and then only in the presence of beta2-GPI. The remaining tissue plasminogen activator (t-PA) of the sample consisting of beta2-GPI, two-chain recombinant t-PA, and plasminogen activator inhibitor (PAI)-1 was measured by a chromogenic assay using the synthetic substrate S-2251, Glu-plasminogen, and soluble fibrin monomer. beta2-GPI protected t-PA activity from inhibition by PAI-1. However, monoclonal aCLs (EY1C8 and EY2C9) inhibited the effect of beta2-GPI on fibrinolytic activity; that is, monoclonal aCLs inhibited fibrinolytic activity by elevating PAI-1 activity. Thrombosis in patients with aCL can be explained in part by both the inhibition of APC anticoagulant activity and the impairment of fibrinolytic activity by aCL.

Large scale purification of human blood CD34(+) cells using a nylon-fiber syringe system and immunomagnetic microspheres.

BACKGROUND: To establish an available, economical technique for the large-scale purification of CD34(+) cells we used a nylon-fiber syringe (NF-S) for depletion of adherent cells and then selected CD 34(+) cells from peripheral blood mobilized by G-CSF, using MAb and magnetic heads. METHODS: PBSC were mobilized and collected from adult, healthy volunteers. With the effect of concentration of anti-CD34 MAb (9C5) on the purification of CD34(+) cells from 1 2 10(8) NF-S treated cells (NF cells), the recovery and the purity of CD34(+) cells was identical for 5, 10, 20, 40 microg of 9C5. In this study, therefore, the concentration of 9C5 was maintained at >5 microg/10(8) NF cells, with a cellhead ratio of 1:10. RESULTS: When half to one-third of leukapheresis product containing 121.5 + or - 26.0 2 10(8) mononuclear cells (mean + or - SD; n = 6) was processed for CD34(+) cell purification, 5.26 + or - 3.01 2 10(7) total purified cells were obtained with a purity of CD34(+) cells at 94.9 - 8.5%. The numbers of CD34(+) cells and total progenitor cells recovered in this process were 4.71 + or - 2.33 2 10(7) cells and 145.9 + or - 121.8 2 10(5) cells, respectively. The total recovery of CD34(+) cells was 37.0 + or - 21.0%. The depletion of monocyte by NF-S reduced the 9C5 anti-human CD34 MAb needed for purification of CD34(+) cells to one-third. Two patients were grafted with peripheral blood CD34(+) cells selected by this procedure and achieved a rapid and consistent hematopoiesis. DISCUSSION: Our clinical data show that these cells are capable of rapid reconstitution of hematopoiesis after high-dose chemotherapy. The procedure contains an additional step; however, consistent high purity of CD34(+) cells in the purified population and cost reduction were achieved, both critical issues in the better purging of malignant cells and for a wide clinical application.

[Gamma-heavy chain disease associated with MALT lymphoma of the duodenum].

We report a case of a 63-year-old woman with gamma heavy chain disease (HCD) associated with mucosa-associated lymphoid tissue (MALT) lymphoma of the duodenum. She was suffering from drug-resistant tonsillitis with high fever. Examination on admission showed leukocytopenia and thrombocytopenia. Bone marrow aspirate revealed granulocytosis and a hypocellular marrow with no increase in plasma cells or atypical lymphocytes. Serum electrophoresis disclosed, in addition to hypogamma-globulinemia, an abnormal band due to the presence of gamma HCD protein. This abnormal protein was a molecular weight of approximately 40 kd as determined by Western blots technique, and belonged to the IgG1 subclass as determined by ELISA with monoclonal antibodies against IgG. An endoscopic examination of the patient's duodenum found a small tumorous lesion, which was confirmed pathologically to be MALT lymphoma. HCD is known to be associated with lymphoproliferative diseases. In this case, gamma HCD had developed as a secondary complication of MALT lymphoma. gamma HCD associated with MALT lymphoma of the duodenum is rare in the literature.