Trans fatty acid blood levels and HFpEF phenotype: from the Aldo-DHF RCT

Background

Prognosis in HFpEF is determined by risk factor control and treatment of comorbidities. Industrially processed TFA (IP-TFA) from partially hydrogenated oils have been linked to altered lipoprotein metabolism, endothelial dysfunction, increased biomarkers of inflammation and increased NTproBNP. In patients with heart failure with preserved ejection fraction (HFpEF), associations of TFA blood levels with patient characteristics are unknown.

Purpose

To evaluate associations of blood TFA with cardiovascular risk factors, aerobic capacity and cardiac function in patients with HFpEF.

Methods

This is a secondary analysis from the Aldo-DHF-RCT. From 422 patients, individual blood TFA were analyzed at baseline in n=404 using the HS-Omega-3-Index® methodology. Patient characteristics were; 67±8 years, 53% female, NYHA II/III (87/13%), ejection fraction ≥50%, E/e' 7.1±1.5; median NT-proBNP 158 ng/L (IQR 82–298). Multiple linear regression analyses, using sex and age as covariates, were used to describe associations of TFA with metabolic phenotype, functional capacity, echocardiographic markers for left ventricular diastolic function (LVDF), and neurohumoral activation at baseline and after 12-months-follow-up (12mFU). To account for randomization group, all analyses were repeated as sensitivity analysis with group as covariate. A significance level of α=5% was used for all tests. As all tests were hypothesis generating without confirmatory interpretation, no correction was applied to counteract the problem of multiple comparisons.

Results

Higher blood levels of the naturally occurring TFA C16:1n-7t were broadly associated with a more favorable lipid profile, lower body weight/central adiposity, lower white blood cell count and lower biochemical markers of non-alcoholic fatty liver disease at baseline/12mFU. Conversely, blood levels of the IP-TFA C18:1n9t were directly associated with lipid risk markers [triglycerides (β=19.7, p<0,001), non-HDL-C (β=7.9, p=0,001), and LDL-C (β=5.4, p=0,011)]. The two IP-TFA C18:2n6 isomers C18:2n6tt and C18:2n6ct were positively associated with HbA1c [(β=14.6, p=0,003) and (β=4.2, p=0,014) respectively]. The IP-TFA C18:2n6tt/-ct isomers were associated with lower submaximal aerobic capacity (distance covered in the 6MWT) at baseline/12mFU. No significant association was found between TFA blood levels and left ventricular filling pressures, left ventricular relaxation or neurohumoral activation. Significant effects of group allocation (spironolactone +/−) were found for the 12mFU outcomes systolic/diastolic blood pressure (all p<0.001), heart rate, E/e$'$ and HbA1c.

Conclusions

In HFpEF patients, higher blood levels of industrially processed TFA, but not of the TFA C16:1n-7t in full fat dairy and meat, were associated with a higher risk phenotype and lower aerobic capacity. Our findings support efforts to remove IP-TFA from the food supply for improving risk factor control in HFpEF patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): German Foundation of Heart Research

Inter-individual differences in the response to an exercise training intervention in patients with metabolic syndrome

Background

Regular physical exercise and standardized exercise training (ET) programmes positively affect a number of metabolic and cardiovascular risk factors. Yet, response to ET varies between patients and between individual risk parameters. We investigated inter-individual responses regarding blood pressure, heart rate, lipids and glucose metabolism, as well as physical fitness to a 16-weeks supervised exercise training protocol in patients with metabolic syndrome (MetS).

Methods

29 MetS patients (20M/9F, age 52–70 y, BMI 24.9–38.2 kg/m2) exercised for 16 weeks in a supervised setting with varying volume and intensity. At baseline and at completion of the programme, blood pressure, heart rate, plasma lipids, glucose and insulin levels, as well as physical fitness were assessed, as were quantitative and morphological leukocyte parameters, cytokines and 86 metabolically relevant plasma proteins. Associations between individual risk parameters, leukocyte profile and plasma proteins were explored by recursive partitioning and network analysis. T-distributed stochastic neighbor embedding and hierarchical clustering were used for clustering based on cardiometabolic target parameters at 16 weeks.

Results

In the whole cohort, VO2peak increased and plasma counts of total leukocytes, neutrophils, monocytes (classical and intermediate), NK cells and effector and regulatory CD4+ lymphocytes, as well as circulating endothelial microvesicles were reduced at the end of the ET programme versus baseline. Plasma levels of carboxylesterase 1 decreased and soluble interleukin-7 receptor increased. Based on patient's cardio-metabolic parameters, three clusters were identified: cluster 1 had lower values of triglycerides, total and LDL cholesterol, cluster 2 had higher levels of triglycerides and cluster 3 had a greater heart rate recovery and lower insulin levels, but higher total and LDL cholesterol levels at follow-up. In cluster 1, absolute and relative NK cell counts were decreased and no morphological activation was observed. In cluster 2, reduced relative counts of NK-T cells were decreased, but their size was increased. In cluster 3, size of most effector leukocyte subtypes (CD8+, CD4+ Teff, NK-T, neutrophils) was increased at follow-up versus baseline. Network analysis suggested four distinct networks of (1) triglycerides, (2) VO2peak, (3) diastolic BP and (4) a cluster containing total and LDL cholesterol, insulin and HR recovery, each associated with partly distinct sets of plasma proteins and leukocyte parameters.

Conclusion

Despite improved physical fitness in all patients participating in the 16 weeks ET programme, inter-individual differences regarding cardio-metabolic target parameters and leukocyte activation was evident. Identification of specific leukocyte responses and of plasma protein “fingerprints” might help to optimize patient-specific prevention programmes, integrating medication and lifestyle optimization.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): DZHK, DSHF

D-Dimer and TAT Measurement in Patients with Deep Venous Thrombosis: Utility in Diagnosis and Judgement of Anticoagulant Treatment Effectiveness

The plasma levels of thrombin-antithrombin III-complexes (TAT) and the fibrin split product D-Dimer were measured in 39 patients with phlebographically proven acute DVT: 34 patients had proximal DVT, 5 had calf DVT The sensitivity of D-Dimer and TAT measurements in the diagnosis of proximal DVT was found to be dependent on the duration of symptoms: 0 to 7 days (n = 27): elevated D-Dimer levels (>120 ng/ml) = 1, D-Dimer Latex test positive (>500 ng/ml) = 1, elevated TAT levels (>6 ng/ml) = 0.88. Eight to 14 days (n = 7): elevated D-Dimer levels = 1, D-Dimer Latex test positive = 0.33, elevated TAT levels = 0.66; specificity: elevated D-Dimer: 0.48, D-Dimer Latex test: 1, elevated TAT: 0.76. Calf DVT patients (n = 5) had elevated D-Dimer levels, negative Latex tests and 3 of them had normal TAT values. Hemostatic and fibrinolytic parameters were also determined in 13 patients during heparin treatment of proximal DVT. Elevated D-Dimer and TAT levels rapidly decreased after initiation of anticoagulant therapy. In 2 of 13 patients a marked increase in D-Dimer and TAT levels was observed in periods of ineffective heparinization, documented by normal or only slightly prolonged thrombin clotting times. We conclude from our results that 1) D-Dimer El A measurement, in contrast to TAT measurement, shows a very high sensitivity in the diagnosis of DVT, 2) due to low specificity this test can only be used to exclude thrombosis in patients with suspected DVT, and 3) the determination of the plasma levels of D-Dimer and TAT may be useful for judging the effect of anticoagulant treatment on thrombotic processes.

Probability of Recurrence of Thrombosis in Patients with and without Factor V Leiden

Activated protein C (APC) resistance is a common risk factor for venous thromboembolism and is associated with the replacement of Arg 506 by Gin in the factor V gene (factor V Leiden). We investigated the risk of recurrence of venous thromboembolism in APC resistant patients heterozygous and homozygous for FV Leiden and compared these patient groups with a group of patients, who had a history of venous thromboembolism, but had neither APC resistance nor the FV Leiden mutation. APC resistance was determined in frozen blood samples from patients with a history of venous thromboembolism, who were not receiving oral anticoagulant (OAC) treatment. The plasma samples were collected between 1984 and 1991. Twenty-one patients in whom APC resistance was found in the stored plasma samples were reinvestigated in 1994 (5 males, 16 females, median [m] age 49 years, range 21-71 years). Twenty-one sex and age matched patients with venous thromboembolism (5 males, 16 females, age m = 50 years, range 25-73 years) investigated during the same time period who had a normal APC resistance test served as a control group. Patients with APC resistance as well as controls were reinvestigated for the presence of FV Leiden by genetic analysis in 1994. Of the 21 APC resistant patients, 5 were homozygous and 16 heterozygous for FV Leiden. Before the study entry homozygous patients had a significantly higher recurrence rate (5/5 patients) compared to the control group, in heterozygous patients (9/16) and controls (9/21) the recurrence rate was not significantly different.

The total observation time was 21 years in patients with homozygous FV Leiden, 83 years in patients with heterozygous FV Leiden and 108 years in controls, excluding the time when patients were on OAC treatment. During the observation time the recurrence rate was highest in patients with homozygous FV Leiden (9.5 % per patient per year), but was similar in patients with heterozygous FV Leiden (4.8% per patient per year) and controls (5% per patient per year). Two of five (40%) homozygous patients, 4/16 (25%) heterozygous and 5/21 (24%) controls had at least one recurrent event during the observation period. The probability for development of thrombosis in the Kaplan-Meyer-Plot analysis was not different between the three groups.

Bearing limitations of our study in mind (retrospective design, relatively small patient number) we conclude that the risk of recurrence after a thromboembolic event is not higher in patients with heterozygous FV Leiden than in patients without this mutation. Thus, it appears that the identification of heterozygous FV Leiden mutation is not an indication for long-term OAC treatment. Also, long-term OAC treatment cannot generally be recommended for homozygous patients with a single thromboembolic event. More definitive conclusions will require larger prospective studies.

A Survey of 215 Non-Hemophilic Patients with Inhibitors to Factor VIII

Information was obtained by questionnaire about 215 nonhemophilic patients who developed inhibitors against factor VIII (antihemophilic factor). The majority of the patients were over 50 years of age, and approximately equal numbers of males and females were reported. Rheumatoid arthritis was present in 8% of the cases, 7% occurred during pregnancy or the post-partum period, and in several there was an association with allergy to penicillin, asthma, “auto-immune” diseases, or malignancy. In 46% of cases, no underlying disorders were identified. Major bleeding was observed in 87 % of patients, and in 22%, death was attributed either directly or indirectly to the presence of the inhibitor.

In 11 of 31 patients receiving no therapy other than supportive transfusions of blood or factor VIII concentrate, the inhibitor disappeared after being present for an average duration of 14 months. Corticosteriods were thought to be effective in abolishing the inhibitor in 22 of 45 patients in whom these were the only drugs administered. Twenty-eight patients received azathioprine as well as corticosteriods; in 19, the inhibitor declined or disappeared during treatment. Finally, 80 patients were treated with cyclophosphamide; in 37 there was a favorable outcome. Inhibitors in children and post-partum patients were more likely to disappear spontaneously or with steroid therapy, whereas those in patients with rheumatoid arthritis or other “autoimmune” disorders required treatment with alkylating agents. However, before any specific therapy can be recommended for this disorder, prospective trials of potential therapeutic agents should be conducted in selected subgroups.

Thrombotic Risk of Women with Hereditary Antithrombin III-, Protein C- and Protein S-Deficiency Taking Oral Contraceptive Medication

The thrombotic risk of women with a heterozygous natural clotting inhibitor deficiency taking oral contraceptives (OC) has not been evaluated. Therefore, a retrospective collaborative controlled cohort-study was carried out in 8 coagulation laboratories and thrombosis units in Austria, Germany and Switzerland.

The incidence of thromboembolism in 48 females heterozygous for hereditary type I deficiency of antithrombin ITT (n = 1.5), protein C. (n = 16) or protein S (n = 17), who had taken OC at least once in their life were compared with that of 48 deficient women, who had never taken OC (controls). Diagnosis of the deficiency state was made in the participating centers. Data on the onset and duration of OC intake and the date and site of thrombotic events were obtained from a questionnaire filled in by the patient or a physician during a visit at a participating center. The observation period in the OC patients was started with onset of OC intake and was terminated when a thromboembolic event had occurred or when OC medication were discontinued. In the patients without OC, the observation period began at an age matched to that of the OC patient and ended when a thromboembolic event had occurred or was continued as long as the corresponding OC patient was on treatment.

In AT Ill-deficient females the probability for thrombosis was significantly higher for patients taking OC compared to the non-OC-patients (Wilcoxon test p = 0.004, Log Rank test p = 0.005). In patients with protein C- ((3-error 0.8) and protein S-deficiency ((3-error 0.05) there was no significant difference between the OC- and non-OC-group. The incidence of thrombosis/patient year in AT III-, PC- and PS-deficient females on OC was 27.5%, 12% and 6.5%, respectively and 3.4%, 6.9% and 8.6%, respectively, in the control patients.

We conclude that females with hereditary antithrombin Ill-deficiency are at high risk for venous thromboembolism when taking OC. Therefore, OC should be strictly avoided in these females and AT III measurement is mandatory in female relatives of AT Ill-deficient patients at young age before starting OC. There is no evidence for an excess thrombotic risk by OC intake in PS-deficient females. In protein C-deficient women OC medication was not associated with a significant increase of thrombosis, but an increased risk cannot be excluded.

Thrombin Augments Vascular Cell-dependent Migration of Human Mast Cells: Role of MGF

Recent data suggest that auricular thrombosis is associated with accumulation of mast cells (MC) in the upper endocardium (where usually no MC reside) and local expression of MGF (mast cell growth factor) (25). In this study, the role of vascular cells, thrombin-activation and MGF, in MC-migration was analyzed. For this purpose, cultured human auricular endocardial cells (HAUEC), umbilical vein endothelial cells (HUVEC) and uterine-(HUTMEC) and skin-derived (HSMEC) microvascular endothelial cells were exposed to thrombin or control medium, and the migration of primary tissue MC (lung, n = 6) and HMC-1 cells (human MC-line) against vascular cells (supernatants) measured. Supernatants (24 h) of unstimulated vascular cells (monolayers of endocardium or endothelium) as well as recombinant (rh) MGF induced a significant migratory response in HMC-1 (control: 3025 ± 344 cells [100 ± 11.4%] vs. MGF, 100 ng/ml: 8806 ± 1019 [291 ± 34%] vs. HAUEC: 9703 ± 1506 [320.8 ± 49.8%] vs. HUTMEC: 8950 ± 1857 [295.9 ± 61.4%] vs. HSMEC: 9965 ± 2018 [329.4 ± 66.7%] vs. HUVEC: 9487 ± 1402 [313.6 ± 46.4%], p <0.05) as well as in primary lung MC. Thrombin-activation (5 U/ml, 12 h) of vascular cells led to an augmentation of the directed migration of MC as well as to a hirudin-sensitive increase in MGF synthesis and release. Moreover, a blocking anti-MGF antibody was found to inhibit MC-migration induced by unstimulated or thrombin-activated vascular cells. Together, these data show that endocardial and other vascular cells can induce migration of human MC. This MC-chemotactic signal of the vasculature is associated with expression and release of MGF, augmentable by thrombin, and may play a role in the pathophysiology of (auricular) thrombosis.

Azidothymidine (AZT) in the Treatment of Symptomatic HIV-1-Infected Hemophiliacs

Twenty-one immunodeficiency virus 1 (HIV 1)-positive hemophilic patients were treated with Azidothymidine (AZT) for symptomatic HIV infection. The median observation period was 20.5 months.

At 25 months the probability of survival was 82%, the probability of progression of disease from CDC III or IV C2 to IV C1 (AIDS) was 20% in patients on continuous AZT treatment and 50% in patients with intermption of treatment. Three patients developed severe leukopenia and 3 patients severe anemii during AZT treatment. In 1 patient a dose-dependent striking increase of transaminases during AZT treatment was observed. In 7 patients treatment was intermpted, in 1 patient because of anemia, in 1 because of pruritus and in 5 patients because of noncompliance.

No signiticant changes in the consumption of clotting factor concentrates and number of bleeding episodes before and during AZT treatment were noted.

We conclude, that both hematological and non-hematological side effects of AZT in HIV 1-infected hemophilic patientr ur. comparable to those seen in other risk groups . AzT does not increase the bleeding tendency in this patient group.

Thromboxane A2 and Prostacyclin Generation in the Microvasculature of Patients with Atherosclerosis – Effect of Low-Dose Aspirin

Generation of thromboxane A2 (TxA2) and prostacyclin (PGI2) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the microvasculature made to determine skin bleeding time was investigated in 7 patients with atherosclerosis (angiographically verified obstructions of the femoral arteries) and in 7 normal control subjects apparently free of atherosclerotic lesions. Similar amounts of TxA2 (measured as thromboxane B2, TxB2) were generated at the site of plug formation in the patients with peripheral vascular disease (PVD) and in the control subjects. Significantly lower levels of PGI2 (measured as 6-keto-prostaglandin F1α, 6-keto- PGF1α) were found in blood from an injury of the microvasculature in the patients compared with the controls. These data do not suggest a major role of the platelet prostaglandin metabolism in the development of atherosclerosis. However, decreased synthesis of PGI2 by endothelial cells might contribute to the development and/or progression of atherosclerotic lesions. In the patients with PVD, low-dose aspirin (50 mg/day for 7 days) resulted in a >90% inhibition of the TxB2 production at the site of plug formation. Following low-dose aspirin 6-keto-PcF1α levels were below 20 pg/ml (limit of sensitivity of our radioimmunoassay procedure) in the majority of the samples.

We therefore conclude that in patients with PVD a decreased synthesis of PGI2 by endothelial cells might contribute to the progression of atherosclerosis. Furthermore, low-dose aspirin treatment results in a similar inhibition of the platelet prostaglandin generation as recently observed in healthy subjects.

Anticardiolipin Antibodies Are Elevated in HIV-1 Infected Haemophiliacs but Do Not Predict for Disease Progression

Levels of anticardiolipin antibodies (ACA) were measured in 55 patients with haemophilia A in serum samples obtained in 1983 and in 1987. Twenty-one patients were negative for anti HIV-1 antibodies in 1983 and remained negative in 1987; 34 patients had anti HIV-1 antibodies in 1983; 17 of these latter patients remained asymptomatic, whereas 17 patients developed ARC or AIDS during the 4 years follow-up. Thirteen anti HIV-1 negative patients had elevated ACA levels in 1983; subsequently, a significant decrease was observed in all these subjects (p <0.001). All anti HIV-1 positive patients had elevated ACA levels in 1983; normal values were found in 9 patients in 1987. Yet, these changes were not significant (p >0.05). ACA levels were significantly higher in HIV-1 infected patients than in those without anti HIV-1 antibodies (p <0.05). There was no difference of ACA levels between the two anti HIV-1 positive patient groups, be it in 1983 or be it in 1987 (p >0.05). There was no correlation of ACA levels with serum IgG concentrations, CD4+ lymphocytes, or the consumption of factor VIII concentrates.

Studies on Tissue Thromboplastin II. Species Specificity*)

1. Purified brain tissue thromboplastins of human, bovine and chicken origin have been tested on homologous and heterologous plasmas.

2. Purified brain tissue thromboplastin is species specific.

3. Lipid extracts from purified brain tissue thromboplastin prepared with pyridin show a negligable residual species specificity, probably caused by a slight contamination with brain tissue thromboplastin.

4. The activity curves of our lipid extracts differ from typical curves expected for lipid activators by a less distinct inhibition in high concentrations probably caused by a different composition of petrol-ether and pyridin extracts.

5. The protein part of tissue thromboplastin does not activate prothrombin in any system.

6. The protein part of tissue thromboplastin of one species could be combined with the lipid part of another species to form an active tissue thromboplastin.

7. The species specificity of these combinations was determined by the source of protein used.

Spontane Faktor-VIII-Inhibitoren

Als spontane (nichthämophile) Faktor-Vlll-lnhibitoren werden Antikörper gegen Faktor VIII bei zuvor gerinnungsnormalen Patienten bezeichnet. Meist ist der F-Vlll-Mangel schwer und dementsprechend die Blutungsneigung ausgeprägt. Die Pathogenese ist heterogen. Laborchemisch findet sich typischerweise eine verlängerte aPTT und ein isolierter F-Vlll-Mangel. Die Antikörper sind polyklonal und zumeist Typ-Il-Inhibitoren. Die Therapie gliedert sich in die Beherrschung der akuten Blutung (hochkonzentrierte humane F-Vlll-Konzentrate, porciner F VIII, aktivierte Prothrombinkomplexpräparate, rekombinanter F Vlla, evtl. zusätzlich Plasmapherese und Immunadsorption - zur Reduktion des Inhibitors) und in die Langzeitreduktion des Titers mit Immunsuppressiva.

Erworbene Faktor-V-Inhibitoren

Erworbene Faktor-V-Inhibitoren sind eine seltene Gerinnungsstörung. Weltweit wurden bisher 72 Fälle publiziert. Die Inzidenz scheint jedoch zuzunehmen, was wahrscheinlich auf den gehäuften Einsatz von Fibrinklebern zurückzuführen ist. Diese Metaanalyse untersucht die prädiponierenden Faktoren, die Pathogenese, diagnostische Methoden, klinisches Erscheinungsbild, therapeutische Möglichkeiten und den langfristigen Verlauf aller bisher publizierten Fälle von Faktor-V-Inhibitoren.

Impaired Fibrinolytic Capacity Predisposes for Recurrence of Venous Thrombosis

The fibrinolytic capacity of 121 patients with a history of venous thrombosis and/or pulmonary embolism was studied by venous occlusion technique, at earliest 3 months after the last thromboembolic episode. After discontinuation of oral anticoagulation treatment the clinical course of the patients was followed and new thromboembolic episodes were noted. During the observation period of 56 ± 18.8 months 45 of 121 patients experienced recurrence of thrombosis. The recurrence-rate was significantly lower in patients with a post-occlusion ELT shorter than 60 min (4.8%/year) than in patients with an ELT longer than 60 min (10.3%/year). It is concluded that the fibrinolytic capacity is a useful parameter for determining the risk of recurrence in patients with venous thrombosis.

The Prevalence of Hereditary Antithrombin-III Deficiency in Patients with a History of Venous Thromboembolism

Antithrombin-III activity was determined in 752 patients with a history of venous thrombosis and/or pulmonary embolism. 54 patients (7.18%) had an antithrombin-III activity below the normal range. Among these were 13 patients (1.73%) with proven hereditary deficiency. 14 patients were judged to have probable hereditary antithrombin-III deficiency, because they had a positive family history, but antithrombin-III deficiency could not be verified in other members of the family. In the 27 remaining patients (most of them with only slight deficiency) hereditary antithrombin-III deficiency was unlikely. The prevalence of hereditary antithrombin-III deficiency was higher in patients with recurrent venous thrombosis.

High Levels of Plasma Protein C in Nephrotic Syndrome

In patients with severe nephrotic syndrome determinations of plasma protein C : Ag levels (8 patients: 5 adults, 3 children) and protein C activity (3 out of 8 patients) revealed significantly elevated plasma protein C concentrations. Furthermore we observed a significant inverse correlation of protein C : Ag to AT III : Ag levels. No protein C : Ag could be detected in the urine of two patients studied. We conclude from our data, that changes of plasma protein C do not contribute to the high thrombotic tendency in nephrotic syndrome.

HTLV-I Antibody Status in Hemophilia Patients Treated with Factor Concentrates Prepared from U.S. Plasma Sources and in Hemophilia Patients with AIDS

Serum samples from 85 Austrian hemophilia patients treated with lyophilized factor concentrates prepared from U.S. plasma sources, 24 hemophilia patients from Georgia on a home therapy program with factor concentrates, and 10 U.S. hemophilia patients with acquired immunodeficiency syndrome (AIDS) were analyzed by two different methods for the presence of antibodies to the major internal antigen of human T-cell leukemia virus I (HTLV-I) p24. All but one, a Georgia sample, were negative. The absence of antibody to HTLV-I p24 in the serum of European hemophilia patients, of U.S. hemophilia patients with no symptoms of AIDS, and of U.S. hemophilia patients with AIDS is interpreted as an indication of the lack of ready transmissibility of HTLV-I in lyophilized factor concentrates.

Protein C Deficiency in Two Austrian Families

Protein C antigen was determined by Laurell rocket immunelectrophoresis in 225 patients with a history of venous thrombosis. Among these patients two females with protein C deficiency were detected. Additional studies in the families of the protein C deficient patients revealed further 7 family members with protein C deficiency. In 8 not anticoagulated patients with protein C deficiency the protein C ranged from 36 to 62% (median: 45%). In one patient on oral anticoagulant treatment protein C antigen concentration was < 10%, FII and F X were 65 and 50%, respectively. The pattern of inheritance was consistent with autosomal dominant inheritance. 5 of the 9 protein C deficient patients had severe thrombotic tendency characterized by recurrent deep venous thrombosis (n = 4), pulmonary embolism (n = 1), probable mesenteric vein thrombosis (n = 1) and superficial thrombophlebitis (n = 2). All protein C deficient patients without thrombosis were less than 17 years old.

T-Cell Alterations in Hemophiliacs Treated with Commercial Clotting Factor Concentrates

Various immunological parameters were determined in 46 patients with severe hemophilia A and in 9 patients with severe hemophilia B. All patients were treated over many years with commercial factor VIII or IX concentrates. Patients with severe classic hemophilia had a significantly reduced relative and absolute number of T-helper cells and a significantly increased relative and absolute number of T-suppressor cells. About half of these patients had an inverse T-helper/suppressor cell ratio. Patients with moderate hemophilia A and severe hemophilia B did not show these abnormalities. Hemophiliacs with an inverse ratio had a significantly higher concentration of serum total protein, IgG and IgM. No relationship between the amount of factor VIII concentrate administered, the HLA-type of the patient, the presence or absence of CMV-antibodies, hepatitis markers, thrombocytopenia and abnormal liver function tests to the T-cell abnormalities could be established. Lymphadenopathy was frequently associated with an inverse ratio. Indirect evidence suggests that the alterations of the immune system began in 1979/80.

A Comparison of the Bethesda and New Oxford Methods of Factor VIII Antibody Assay

A collaborative trial has been carried out under the auspices of the International Committee on Thrombosis and Haemostasis to compare the Bethesda and New Oxford methods of antibody assay. It was found that errors between laboratories were much greater than those within laboratories and each laboratory had a bias whereby it always rated samples high or low with respect to the other laboratories. However there was excellent agreement in the order in which laboratories ranked antibody samples and if a standard antibody sample could be provided there would be a significant improvement in numerical agreement between laboratories. On average, for this exercise, a result for a given sample in Bethesda units was 1.21 times the result in New Oxford units although it must be stressed that this ratio could vary from sample to sample.

Effect of Treatment with Activated Prothrombin Complex Concentrate (FEIBA) on Factor VIII-Antibody Level

The influence of treatment with an activated prothrombin complex preparation (FEIBA) on the antibody level was studied in 10 haemophiliacs with an antibody to factor VIII. The antibody level was observed to rise at least once in five patients, while in the remaining five patients no rise occurred. In all, 6 out of 31 treatments were followed by an anamnestic rise of the antibody level, corresponding to 19.4%. A rise of the inhibitor level following FEIBA treatment is likely to occur in patients who show a marked antibody rise after factor VIII treatment (good responders), but have a low antibody level at the time of treatment. High doses of FEIBA and simultaneous transfusion of red cells may also enhance the likelihood of an anamnestic response. Stimulation of antibody production is probably due to the presence of small amounts of factor VIII in this preparation.

Levels of Prothrombin Fragment F1+2 in Patients with Hyperhomocysteinemia and a History of Venous Thromboembolism

Increased thrombin generation occurs in many individuals with inherited defects in the antithrombin or protein C anticoagulant pathways and is also seen in patients with thrombosis without a defined clotting abnormality. Hyperhomocysteinemia (H-HC) is an important risk factor of venous thromboembolism (VTE). We prospectively followed 48 patients with H-HC (median age 62 years, range 26-83; 18 males) and 183 patients (median age 50 years, range 18-85; 83 males) without H-HC for a period of up to one year. Prothrombin fragment Fl+2 (Fl+2) was determined in the patient’s plasma as a measure of thrombin generation during and at several time points after discontinuation of secondary thromboprophylaxis with oral anticoagulants. While on anticoagulants, patients with H-HC had significantly higher Fl+2 levels than patients without H-HC (mean 0.52 ± 0.49 nmol/1, median 0.4, range 0.2-2.8, versus 0.36 ± 0.2 nmol/1, median 0.3, range 0.1-2.1; p = 0.02). Three weeks and 3,6,9 and 12 months after discontinuation of oral anticoagulants, up to 20% of the patients with H-HC and 5 to 6% without H-HC had higher Fl+2 levels than a corresponding age- and sex-matched control group. 16% of the patients with H-HC and 4% of the patients without H-HC had either Fl+2 levels above the upper limit of normal controls at least at 2 occasions or (an) elevated Fl+2 level(s) followed by recurrent VTE. No statistical significant difference in the Fl+2 levels was seen between patients with and without H-HC. We conclude that a permanent hemostatic system activation is detectable in a proportion of patients with H-HC after discontinuation of oral anticoagulant therapy following VTE. Furthermore, secondary thromboprophylaxis with conventional doses of oral anticoagulants may not be sufficient to suppress hemostatic system activation in patients with H-HC.

Inhibition rather than Enhancement of Hemostatic System Activation during Initiation of Oral Anticoagulant Treatment

Coumarin-induced skin necrosis is believed to be due to a transient hypercoagulable state resulting from a more rapid decline of the protein C activity relative to that of coagulation factors (F) II, IX and X during initiation of oral anticoagulant therapy. We studied hemostatic system activation during early oral anticoagulant treatment with a technique that investigates coagulation activation in the microcirculation.

We determined in 10 healthy volunteers the concentrations of prothrombin fragment F1+2 (f1.2) and thrombin-antithrombin complex (TAT) in blood emerging from an injury of the microvasculature (bleeding time incision) before and after initiation of both high-inten- sity and low-intensity coumarin therapy. In addition, f1.2, TAT, activated F VII (F Vila) and the activities of FII, F VII, F X and protein C were measured in venous blood.

A rapid decline of F VII and protein C was observed in venous blood with activities at 24 h of 7 ± 1% and 43 ± 2%, respectively, during the high-intensity regimen. A 20 to 30% reduction of f1.2 and TAT was seen in venous blood at 72 h with no major difference between the high- and the low-intensity regimen. F Vila levels were substantially affected by anticoagulation with a >90% reduction at 48 h during the high-intensity regimen. Following high-intensity coumarin, a >50% decrease in the fl.2 and TAT levels was found in shed blood at 48 h suggesting substantial inhibition of thrombin generation during early oral anticoagulation. An increase in the f1.2 and TAT levels was seen neither in shed blood nor in venous blood.

Our data do not support the concept of a transient imbalance between generation and inhibition of thrombin as the underlying pathomechanism of coumarin-induced skin nekrosis.

The Risk of Recurrent Venous Thromboembolism in Patients with and without Factor V Leiden

Thromboprophylaxis with oral anticoagulants up to six months is established in patients after a first venous thromboembolic event (VTE). The risk of recurrent VTE is still considerable thereafter, and it is uncertain whether some patients might benefit from extended anticoagulation. We performed a prospective, multicenter trial (4 thrombosis centers) and evaluated in 380 patients with a first or recurrent VTE (patients with a deficiency of antithrombin, protein C, protein S or plasminogen; cancer; or an antiphospholipid antibody syndrome were excluded) the risk of recurrence after discontinuation of secondary thromboprophylaxis with oral anticoagulants. It was the aim of the study to evaluate whether patients with factor V Leiden are at an increased risk of recurrent VTE. 112 (29.5%) patients were carriers of factor V Leiden (26.9% heterozygous, 2.6% homozygous). After a median observation time of 19.3 months the overall recurrence rate of VTE was 9.9%. Recurrent deep vein thrombosis and/or pulmonary embolism occurred in 26 of 268 patients without factor V Leiden (9.7%) and in 10 of 112 patients with factor V Leiden (8.9%). The probability of recurrent VTE two years after discontinuation of oral anticoagulants was 12.4% (95% Cl 7.8-17) in patients without factor V Leiden and was 10.6% (95% Cl 3.8-17.4) in carriers of the mutation. This difference was statistically not significant. Patients with factor V Leiden are not at a higher risk of recurrent VTE within two years after discontinuation of oral anticoagulants than patients without factor V Leiden. Balancing the risk of recurrent VTE and bleeding from oral. anticoagulants, patients with factor V Leiden are not likely to benefit from oral anticoagulant therapy extended beyond six months.

Prothrombin Fragment F1+2 Is not Predictive for Recurrent Venous Thromboembolism

It would be important to estimate in advance the risk of recurrent thrombosis. Deficiencies of antithrombin, protein C or protein S, or resistance to activated protein C are associated with a biochemically detectable prethrombotic state. It is thus far unknown whether in patients with a history of thromboembolism but without a defined clotting abnormality a heightened coagulation activation is detectable.

We investigated the value of prothrombin fragment Fl+2 (FI+2) as a predictor of recurrent venous thromboembolism. Furthermore, we compared the Fl+2 levels of thrombosis patients without a defined clotting defect to those of Factor V Leiden patients with a history of venous thrombosis and to those of healthy controls. 180 patients without a defined clotting abnormality and 73 patients with Factor V Leiden were prospectively followed after discontinuation of oral anticoagulants for venous thrombosis and Fl+2 was measured at regular intervals.

Recurrent venous thromboembolism occurred in 23 (9%) of the 253 patients. Before or at several time points after oral anticoagulants, no significant difference in Fl+2 levels was found in patients with and without recurrent thrombosis. Fl+2 levels at 3 weeks and prior to recurrence were not significantly different in both patient groups. Over a one-year observation period, Fl+2 levels of both patients with and without Factor V Leiden were higher than those of the controls. No difference in Fl+2 was seen between patients with and without Factor V Leiden.

We conclude that monitoring of Fl+2 is not suitable for identification of individuals at risk of recurrent venous thrombosis. Permanent hemostatic system activation is detectable both in patients with a defined abnormality of the clotting system and in patients in whom a particular defect has not (yet) been identified.

Antithrombin III Concentrates-Are they Clinically Useful?

Treatment with AT III concentrates is a good example for the discrepancy between the optimistic expectations based on theoretical considerations or animal experiments and the result of clinical studies. 15 years after the introduction into clinical practice, a benefit for patients treated with AT III concentrates has not been proven. In hereditary antithrombin III deficiency, randomized clinical trials are completely lacking and only few and small sized randomized studies were performed in patients with acquired AT III deficiency. In none of these trials, a significant clinical benefit with regard to reduction of morbidity or mortality was detectable. Based on the published data, one can state that AT III concentrates may be beneficial in some special clinical situations in patients with hereditary antithrombin III deficiency (such as delivery, acute serious thromboembolic complications and postoperative thromboprophylaxis). In acquired AT III deficiency, there is no proven indication for the use of AT III concentrates.

Elimination of Acquired Factor VIII Antibodies by Extracorporal Antibody-based Immunoadsorption (Ig-Therasorb®)

Treatment of potent factor VIII antibodies is a difficult problem. In some cases a reduction ofthe antibody titer is necessary for effective treatment with human factor VIII concentrates. We describe a new method for extracorporal eliminationof factor VIII antibodies (antibody-based immunoadsorption). Blood is drawn from an antecubital vein, citrated, and plasma is separated with a rotating membrane. Plasma passes alternately through one of two columns filled with sepharose-coupled polyclonal sheep antibodies to human immunoglobulins (Ig-Therasorb00), whereas the other column is regenerated. Each cycle has a duration of 15 min. Three patients with high titer factor VIII antibodies (one hemophiliac and 2 with spontaneous antibodies; titers 29, 132, and 313 BU/ml, respectively) were treated. The average reduction of the antibody titer was 76.1 ± 17.2% per session. In each patient 4 sessions were necessary to reduce the antibody titer to < 1 BU/ml. The mean processed plasma volume was 6731 ± 640 ml and the mean duration of each session 3.9 ± 0.7 h. Serum IgG, IgA and IgM levels decreased by 75.3 ± 11.9%, 62.9 ± 19.1%, and 54.8 ± 23.8% respectively. The procedure was tolerated without any side effects. Thus, rapid elimination of factor VIII inhibitors can be achieved with antibody-based immunoadsorption, which can be lifesaving in some cases. This promising method should be evaluated in a larger number of patients.

Studies on the Neutralizing Effects of Protamine on Unfractionated and Low Molecular Weight Heparin (Fragmin®) at the Site of Activation of the Coagulation System in Man

In a double-blind, randomized, cross-over study the neutralizing action of protamine towards unfractionated heparin (UFH, 150 U/kg i.v.) and a low molecular weight heparin (LMWH, Fragmin®, 100 anti-Xa U/kg i.v.) was investigated in 15 healthy subjects in vitro by measuring activated partial thromboplastin time (APTT), thrombin time (TT) and anti factor Xa activity (anti-Xa) in venous blood and in vivo by determination of prothrombin fragment 1.2 (f1.2) and thrombin-antithrombin III complexes (TAT) in venous blood and in shed blood. UFH and LMWH caused a prolongation of APTT and TT, an increase in anti-Xa and significantly inhibited f1.2 and TAT formation in shed blood, whereas only a minimal effect on TAT and f1.2 formation in venous blood was noted. Administration of 1 mg protamine/100 U UFH resulted in a near complete reversal of APTT, TT and anti-Xa, whereas lower doses (0.25 and 0.5 mg) were less effective. The effects of UFH on f1.2 and TAT generation in shed blood were partially (60-70%) neutralized only by the high dose (1.0 mg). Application of 1 mg protamine/100 anti-Xa U LMWH caused a near complete reversal of both APTT and TT but had only a weak effect on anti-Xa. In shed blood, the effect of LMWH on TAT and f1.2 formation was reversed by protamine only by 14% and 23% respectively. Our data do not support the concept that to reduce the incidence of protamine’s potential clinical side effects, the administration of a lower dose of protamine than 1 mg protamine/100 U UFH is justified. Furthermore, a significant residual impairment of hemostasis is still detectable after administration of the recommended dose of protamine to neutralize the anticoagulant effects of a LMWH preparation.

Post-Partum Factor VIII Inhibitors

In a retrospective study 51 published cases of post-partum factor VIII inhibitors were analyzed with regard to the outcome according to treatment. The overall outcome was favorable with 97% survival at two years. The probability of complete remission (CR, absence of the inhibitor and normalization of factor VIII activity) was almost 100% at 30 months. Steroid treatment appears to be not superior to no treatment, but patients treated with immunosuppressive drugs (cyclophosphamide, azathioprine, 6-mercaptopurine) had a significantly shorter time to CR. In the absence of a randomized trial this analysis may be helpful for decision-making in women with factor VIII post-partum inhibitors. Because of the retrospective study design, conclusions have to be regarded with caution.

The Risk of Thromboembolism in Asymptomatic Patients with Protein C and Protein S Deficiency: A Prospective Cohort Study

Background: Prospective studies on the incidence of thrombosis in asymptomatic individuals with hereditary protein C- or protein S deficiency have not been performed so far.

Objective: We have carried out a prospective cohort study in 44 asymptomatic protein C- and protein S deficient subjects and in 49 asymptomatic non-deficient relatives (age at study entry > 14 years) of symptomatic deficient patients.

Methods: 20 asymptomatic protein C deficient (median age 20 years) and 24 asymptomatic protein S deficient patients (median age 21.5 years) were prospectively followed and compared with 20 asymptomatic non-deficient relatives (median age 25 years) of protein C- and 29 (median age 27 years) of protein S deficient patients. The total observation period was 118.8 patient years for protein C deficient and 92.8 for protein S deficient patients. Patients were not on anticoagulants except for short duration in case of high risk situations.

Results: Eight thromboembolic events (1 pulmonary embolism, 1 deep vein thrombosis + pulmonary embolism, 3 deep vein thrombosis, 1 caval vein thrombosis and 2 superficial vein thrombosis) occurred in 6 deficient patients. The incidence of thromboembolism was 2.5% per patient year for protein C deficient and 3.5% per patient year for protein S deficient patients. 4 events occurred spontaneously, in 2 patients thromboembolic events were triggered by high risk situations (caesarean section, minor trauma). In the controls no thromboembolic events occurred. The probability for thromboembolism was significantly higher in protein C and protein S deficient patients compared to the control group (Wilcoxon test, p = 0.002, log rank test, p = 0.001). One major and 5 minor uneventful surgeries were carried out in the deficient patients using heparin prophylaxis. 1/8 pregnancies was complicated by superficial vein thrombosis during the second trimester despite prophylactic heparin administration. The same pregnancy was complicated by pulmonary embolism 5 weeks after delivery after discontinuation of heparin.

Conclusions: Asymptomatic deficient relatives of symptomatic patients with protein C or protein S deficiency are at an increased risk of thrombosis compared to nondeficient individuals. Prophylactic treatment seems to be highly effective in high risk situations.

Effects of a Low Molecular Weight Heparin (Fragmin®) and of Unfractionated Heparin on Coagulation Activation at the Site of Plug Formation In Vivo

The clinical benefits of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) have been shown in many trials. However, the mode of action of heparin has not been fully elucidated. Thus, we wanted to study the effects of UFH and LMWH in vivo by measuring coagulation activation markers in blood obtained directly from a vascular injury site. In a double-blind, randomized, 3-way, cross-over study 18 healthy volunteers were given UFH (150 U/kg s.c.) and 2 doses of LMWH [35 U/kg s.c. (low dose, Id), 75 U/kg s.c. (high dose, hd)]. Prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and fibrinopeptide A (FPA) were measured in bleeding time blood and in venous blood before and after drug application. In addition, the effects of UFH and LMWH on in vitro coagulation tests were studied. Compared to base line, UFH and both IdLMWH and hdLMWH caused significant reductions of F1+2, TAT and FPA in bleeding time blood at 2 h. A marked effect of UFH and of hdLMWH was also seen at 5 h. The inhibition of FPA generation was more pronounced after hdLMWH compared to IdLMWH. In venous blood, UFH and LMWH caused reductions of F1+2, but not of TAT and FPA. In vitro, UFH predominantly affected the anti-IIa assays (activated partial thromboplastin time, thrombin time) and LMWH mainly the anti-Xa test system. Using a technique that investigates the activated coagulation system in vivo, a time- and dose dependent inhibitory effect of heparin on coagulation activation was detectable. Therefore, in our experimental setting a preferential inhibition of a particular portion of the coagulation system by one of the two heparin preparations was not detectable.

Recurrent, Isolated Factor X Deficiency in Myeloma: Repeated Normalization of Factor X Levels after Cytostatic Chemotherapy Followed by Late Treatment Failure Associated with the Development of Systemic Amyloidosis

We describe the case of a 64-year-old woman with isolated severe factor X deficiency associated with kappa light chain myeloma. At the time of diagnosis there was no evidence for amyloidosis. Complete remission (CR) of myeloma as well as normalization of factor X levels were achieved after cytostatic chemotherapy. Subsequently, factor X deficiency recurred twice without any evidence for relapse of myeloma. The first time factor X normalized again following cytostatic treatment, the second time, however, factor X deficiency was refractory to chemotherapy. Finally, relapse of myeloma became evident associated with rapidly progressing, systemic amyloidosis, which was fatal within a few months. Initially, factor X infusion studies showed a normal recovery, but when amyloidosis became overt the recovery decreased to 0%. We assume that factor X deficiency was due to a binding of factor X to kappa light chains associated with the proliferation of the malignant myeloma cell clone.

Diagnosis of Protein C Deficiency in Patients on Oral Anticoagulant Treatment: Comparison of Three Different Functional Protein C Assays

The efficacy of three different protein C activity assays and of protein C antigen determination for the diagnosis of protein C deficiency was studied in 13 protein C deficient patients (11 with type I, 2 with type II deficiency) and in 51 presumably nondeficient patients (control group), both groups being on oral anticoagulant (OAC) treatment. For protein C activity measurement (1) the assay according to Francis (slightly modified) with thrombin activation and measurement of activated protein C in the aPTT system, (2) an assay using Protac activation and chromogenic substrate (Protac-CS) and (3) an assay using Protac activation and the aPTT system (Protac-PTT) were used. Protein C antigen was determined by Laurcll immunoelec-trophoresis. The three activity assays gave different results, with the highest values obtained by the Protac-CS assay and the lowest values by the Protac-PTT assay. The Francis assay gave intermediate results.

Protein C activity and antigen values were significantly lower in protein C deficient patients compared to the control group. Protein C activity tests had a higher discriminative power than the antigen determination. After taking into account the intensity of treatment, by the Francis assay all deficient and non-deficient patients were correctly classified, by the Protac-CS and the Protac-PTT assay 2 and 4 patients, respectively, were misclas-sified and by the antigen assay 8 patients were misclassified. Calculation of the ratios of protein C activity to factor II activity was of high discriminative power.

We conclude that for diagnosis of protein C deficiency protein C activity tests are superior to antigen determination not only in type II but also in type I deficient patients. Certain statistical procedures can further improve the discrimination between deficient and non-deficient patients.

Immune Reactive Factor IX in Acquired Factor IX Deficiency

Factor IX-antibody-neutralizing material has been estimated in plasmas of patients with acquired factor IX deficiency. In patients with liver cirrhosis and patients who had been treated with L-Asparaginase the plasma neutralized an amount of antibody expected from the biological activity. In patients treated with phenprocoumon and in one patient with biliary obstruction an excess of factor IX-antibody neutralizing material was found. This inactive factor IX probably represents a precursor molecule of factor IX.

Evidence for an Increased Generation of Prostacyclin in the Microvasculature and an Impairment of the Platelet α-Granule Release in Chronic Renal Failure

The formation of prostacyclin (PGI2) and thromboxane A2 and the release of beta-thromboglobulin (beta-TG) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the micro vasculature made to determine bleeding time, was studied in patients with end-stage chronic renal failure undergoing regular haemodialysis and in normal subjects. In the uraemic patients, levels of 6-keto-prostaglandin F1α (6-keto-PGF1α) were 1.3-fold to 6.3-fold higher than the corresponding values in the control subjects indicating an increased PGI2 formation in chronic uraemia. Formation of thromboxane B2 (TxB2) at the site of plug formation in vivo and during whole blood clotting in vitro was similar in the uraemic subjects and in the normals excluding a major defect in platelet prostaglandin metabolism in chronic renal failure. Significantly smaller amounts of beta-TG were found in blood obtained from the site of vascular injury as well as after in vitro blood clotting in patients with chronic renal failure indicating an impairment of the a-granule release in chronic uraemia. We therefore conclude that the haemorrhagic diathesis commonly seen in patients with chronic renal failure is - at least partially - due to an acquired defect of the platelet a-granule release and an increased generation of PGI2 in the micro vasculature.

Factor IX-Inhibitors

1. Two patients with severe hemophilia B and an acquired inhibitor against factor IX are described.

2. The inhibitors inactivate factor IX irreversibly. The speed of inactivation is very fast and cannot slowed down by dilution of the inhibitor or by lowering of the incubation temperature. Factor IX of serum is inactivated to a higher degree than factor IX of plasma. Factor IX inhibitors are more sensitive to dilution than factor VIII inhibitors.

3. The inhibitor protein is eluted from the Sephadex G-200 column with the G-peak. On Chromatography on DEAE-cellulose two activity peaks are obtained.

4. Immunologically the inhibitors belong predominantly to the immune globulins of the G-class, but it cannot be excluded that the activity is also associated with IgA. As light chains kappa chains were found in one case.

Activation of Factor X

1. Methods have been developed for the preparation of factor VII free of prothrombin and factor X, and of factor X with only a very low contamination with factor VII.

2. Factors VII and X could be found with one stage methods in purified prothrombin prepared according to Seegers.

3. Purified prothrombin was chromatographed on DE AE-cellulose. Two active fractions could be eluted, the first with the characteristics of Seegers’ DE AE-Prothrombin, the second with the characteristics of factor X.

4. It was confirmed that DE AE-Prothrombin does not activate to thrombin in 25% citrate, and does not generate autoprothrombin C.

5. The combination of both clotting active fractions coming from the DEAE-column restores the properties of non-chromatographed prothrombin.

6. DE AE-cellulose chromatography of prothrombin does not induce a molecular change of prothrombin, but separates factor X from prothrombin.

7. Factor X can be activated with tissue thromboplastin-factor VII or with high concentrated neutral salt solutions to a substance with the biological characteristics of autoprothrombin C.

8. TAMe activity is generated in factor X preparations after incubation with tissue thromboplastin and calcium.

9. Factor VII cannot be transformed into autoprothrombin C under the conditions tested.

10. Factor VII is necessary for the activation of factor X with tissue thromboplastin but not with RVV.

11. The amount of factor X available determines the amount of autoprothrombin C formed, whereas thromboplastin and factor VII influence the rate of the reaction.

12. The final conclusion is that activated factor X is similar to or identical with autoprothrombin C.

A Hitherto not Described Enzyme Defect in Thrombasthenia: Glutathionreductase Deficiency

Two cases of thrombasthenia in the same family are described in which a deficiency of glutathionreductase and a reduction of reduced glutathion was found in the platelets, but no in the erythrocytes.

Eine einfache Methode zur Herstellung von menschlichem Faktor-VII-Mangelplasma

Es wird eine Methode zur Herstellung eines artifiziellen Faktor-VII-Mangelplasmas beschrieben, wobei Faktor VII von den Faktoren II und X durch Chromatographie an DEAE-Zellulose abgetrennt wird. Vergleichende Teste mit dem artifiziellen Faktor-VII-Mangelplasma und einem natürlichen Faktor-VII-Mangelplasma ergaben eine befriedigende Übereinstimmung der Werte.

Gerinnungsveränderungen bei orthotoper Lebertransplantation am Hund

Bei 16 Hunden wurden bei orthotopen Auto- und Homotransplantationen der Leber Gerinnungsuntersuchungen durchgeführt. Während die Anästhesie, die Präparation der Lebergefäße und Manipulationen an Leber und Lunge keine Gerinnungsveränderungen hervorriefen, kam es nach Anlegen des äußeren venösen Bypass und Entnahme der Leber zu einem Abfall von Fibrinogen, Thrombozyten, Faktor II, Faktor VIII und Antithrombin III. Diese Veränderungen werden als Ausdruck einer Verbrauchskoagulopathie angesehen. Eine leichte Fibrinolyse war gewöhnlich erst am Ende der anhepatischen Phase nachweisbar und dürfte sekundär sein. Nach Implantation der Leber war nach kurzer Latenzzeit ein Wiederanstieg der oben genannten Faktoren und der Thrombozyten zu beobachten. Die möglichen Ursachen für das Auftreten der Verbrauchsreaktion werden diskutiert.

A New Type of Coagulation Inhibitor

1. In 2 patients blood coagulation inhibitors have been found. The first patient showed pancytopenia, splenomegaly and increase of macroglobulins in serum, no definite clinical diagnosis could be established. The second patient had a history of thromboembolic diseases, but appeared healthy at the time of investigation.

2. Clotting time, partial thromboplastin time and prothrombin time were prolonged in both patients. All clotting factors were normal if tested in dilution. Plasma and serum of the patients prolonged the partial thromboplastin time and prothrombin time of normal plasma.

3. Using partially purified clotting factors it could be shown that the inhibitors inhibit the activation of prothrombin by prothrombin activator (reaction product of F Xa+ F V+lipid). The velocity of thrombin generation and the amount of thrombin generated was reduced.

4. The inhibitory activity in both cases was present in the macroglobulin peak after gel filtration, slight activity was detected also in the G-peak in case 2. After DEAEchromatography, activity appeared in both cases in those fractions which contain IgM, in case 2 also in the first protein fractions containing only IgG.

5. Inhibitor activity could be reduced in both cases only be incubation with anti-IgM antiserum.

6. It is concluded that the inhibitor in case 1 is IgM and in case 2 IgM-IgG.

New Aspects in Thrombosis Research: Possible Role of Mast Cells as Profibrinolytic and Antithrombotic Cells

Venous thromboembolism represents a significant cause of morbidity worldwide. The factors that underly thrombophilia are manifold. The concept of Virchow defines the well known triad of stasis, humoral factors, and pathologies of the vascular wall. In the current article, an additional factor, the “accumulation of repair cells” is discussed. This novel concept highlights the mast cell that accumulates around thrombosed vessels and provides a number of important repair molecules including heparin, profibrinolytic tPA, and fibrinogenolytic β-tryptase. Thus, mast cell recruitment and activation may result in local thrombolysis and prevention of coagulation. In line with this concept, mast cell-deficient mice are more susceptible to lethal thrombogenic stimuli compared to normal mice. The factors (cytokines) that trigger mast cell accumulation and release of repair molecules have also been identified – the most important one appears to be stem cell factor (SCF). All in all, our novel concept suggests that the patho-physiology of thrombosis may involve a “physiologic” cell that provides the same repair molecules that are used for treatment of thrombotic disorders by the physician. Whether an altered availability of components of this cellular repair system can predispose for thrombophilia remains to be determined.