Coagulation activation in young survivors of myocardial infarction (MI)--a population-based case-control study

Formation of an occlusive thrombus by exposure of tissue factor (TF) to circulating blood and subsequent triggering of coagulation by TF-FVIIa complexes on ruptured atherosclerotic plaques is thought to be a key event in acute MI. Tissue factor pathway inhibitor (TFPI) is a potent inhibitor of TF-induced coagulation by neutralizing FXa and inhibiting the TF-FVIIa complex. A case control study was conducted to investigate the role of coagulation activation in MI. Sixty-two patients with verified MI, 40-60 yrs of age, were recruited into the study and examined 1-4 years after the acute coronary event. Thrombin-antithrombin complex (TAT) was significantly increased in MI patients (8.2 +/- 12.9 microg/l vs. 3.9 +/- 2.6 microg/l, p=0.01). In contrast, FVIIa was lower in MI patients (41 +/- 13 mU/ml vs. 48 +/- 15 mU/ml, p=0.003) accompanied by an increase in plasma free TFPI antigen (20.9 +/- 5.0 ng/ml vs. 19.2 +/- 4.9 ng/ml, p=0.03). Significant trends for increase in triglycerides and total cholesterol across quartiles of free TFPI Ag were found in both groups, whereas HDL cholesterol decreased across quartiles of TFPI among control subjects. The compensatory increase in plasma free TFPI with established lipid and haemostatic risk factors were abrogated in the MI patients. An apparent increase in the basal activation of the coagulation system was observed in young patients with MI. Enhanced coagulation activation was accompanied by a decrease in FVIIa and increase in free TFPI Ag, probably reflecting a modest triggering of TF-induced coagulation in these patients.     

Do antiphospholipid antibodies interfere with tissue factor pathway inhibitor?

This study was conducted to investigate whether antiphospholipid antibodies (APA) can interfere with the phospholipid-dependent inhibition of coagulation exerted by tissue factor pathway inhibitor (TFPI). Eleven patients with APA and eleven healthy controls matched for age and gender were enrolled. Blood samples were drawn before and 5 minutes after an intravenous injection of unfractionated heparin 5000 IE, which is known to cause TFPI release in healthy individuals. The preheparin samples showed significantly higher TFPI free antigen levels in the APA positive patients than in the controls (21.7 vs. 14.2 ng/ml, p = 0.03). TFPI activity as measured in a chromogenic substrate assay also was higher in patients, but this difference was not statistically significant (1.13 vs. 1.01 U/ml, p = 0.2). The TFPI levels showed a considerable rise in both patients and controls after heparin injection. In both assays, the postheparin levels were significantly higher in patients than in controls (TFPI antigen: 179 vs. 153 ng/ml, p = 0.05; TFPI activity: 3.26 vs. 2.51 U/ml, p = 0.03). A modified diluted prothrombin time assay (dPT) was used to measure TFPI anticoagulant activity. In this assay, samples from the patients with the strongest effect of lupus anticoagulants (LAs) on preheparin coagulation times showed little or no increase after heparin injection. This result may reflect an inhibition of TFPI anticoagulant activity by strong LAs. In conclusion, we have found that patients with APA have higher TFPI amidolytic activity/antigen level both before and after heparin stimulation of TFPI release. These observations do not explain the higher thrombotic risk in these patients but may reflect an upregulated tissue factor activity, which has been demonstrated in these patients. TFPI anticoagulant activity, however, as measured in a dPT assay, may be inhibited by strong LAs.     

Increased risk of gestational vascular complications in women with low free tissue factor pathway inhibitor plasma levels out of pregnancy

Tissue factor pathway inhibitor (TFPI) plays a crucial role in haemostasis by regulating TF-induced initiation of coagulation. Since it is expressed by endothelial and trophoblastic cells, TFPI is of particular importance at the placental level and might be involved in the occurrence of gestational vascular complications (GVC). In the present study, we investigated plasma free TFPI antigen in four groups of women: healthy non-pregnant women without history of pregnancy complications; women at the beginning (<12 weeks) and women during the third trimester of a normal pregnancy; women with late pregnancy complications (pre-eclampsia / HELLP syndrome, intra-uterine fetal death, fetal growth retardation) at the time of obstetrical event and/or at distance from pregnancy. In normal pregnancy, TFPI increased between first trimester and delivery (median 5.0 ng/ml vs. 7.1 ng/ml; p<0.0001) but remained lower than in non-pregnant controls (median 8.2 ng/ml; p<0.0001). In patients, when measured concomitantly to the obstetrical event, TFPI showed no difference with normal late pregnancy levels. In contrast, at distance from pregnancy, in the absence of any hormonal influence, TFPI was significantly lower than in non-pregnant controls (median 5.9 vs. 8.2ng/ml, p < 0.0001). After categorisation into quartiles, an inverse dose-effect relationship was demonstrated between TFPI categories recorded apart from pregnancy and GVC risk, with a crude odds ratio of 43.5 (95% confidence interval 8.2-230) for patients with TFPI values in the lowest quartile (< 5.7 ng/ml). In conclusion, low free TFPI at distance from pregnancy appears to be a strong indicator of GVC risk.     

Quantification of tissue factor pathway inhibitor in human seminal plasma and in human follicular fluid

Introduction: Tissue factor pathway inhibitor (TFPI) is a multivalent Kunitz-type serine proteinase inhibitor, which plays a central role in the extrinsic pathway of blood coagulation. It inhibits activated factor X directly and factor VIIa/tissue factor via a quaternary complex. The composition of human semen is governed by the ejaculatory mixing of sperm-rich epididymal fluid, with secretion provided by the accessory sex glands. It is composed of more than 30 proteins including coagulation and liquefaction proteins. Ovarian follicular fluid plays an important biological role in folliculogenesis and oocyte maturation, and it remains in a hypocoagulable state until ovulation. Materials and methods: TFPI levels were measured in ovarian follicular fluid gained from the punctured follicles of superovulated women (n=70), and, for the first time, in seminal plasma of 28 healthy ejaculate donors and 23 infertile patients with oligozoospermia, asthenozoospermia, or teratozoospermia. Results: TFPI concentrations determined in liquor folliculi (median 298 ng/ml, 90% range 109–648 ng/ml) were four times higher than the levels found in human blood of healthy individuals. TFPI concentrations in seminal plasma samples of infertile men were significantly reduced (median 2.20 ng/ml, 90% range 0.28–6.02 ng/ml, p<0.07) in comparison to healthy donors (median 3.55 ng/ml, 90% range 0.93–7.90 ng/ml). Conclusions: The high TFPI levels measured in the ovarian follicular fluid underline the physiological importance of this inhibitor for maintaining the hypocoagulable state. The decreased TFPI concentrations in seminal plasma of infertile men support the possible correlation between the coagulation properties of ejaculated semen and male fertility.     

Fluctuations in plasma levels of thrombomodulin in patients with DIC.

Plasma thrombomodulin (TM) has attracted considerable attention as a marker of endothelial cell membrane injury. We examined fluctuations in plasma TM levels in patients receiving therapy for the disseminated intravascular coagulation syndrome (DIC) using an enzyme immunoassay. Sixty healthy controls and 18 patients with DIC were studied. The mean +/- SD of the TM values initially measured immediately after the onset of DIC was 42.00 +/- 20.85 ng/ml, which was markedly increased as compared with the control value of 15.36 +/- 4.85 ng/ml (p < 0.001). Fluctuations in the TM levels over time were studied after dividing the patients according to the presence or absence of improvement in the underlying disease and improvement or lack thereof in the coagulation findings. Group I showed improvement in both categories, Group II showed improvement only in the latter, and Group III showed no improvement in either category. In Group I, the mean +/- SD of initial measured TM levels was 37.02 +/- 10.12 ng/ml and the mean of final values decreased to 58.9% of the initial value. This decrease was significant by paired Student's t-test (p < 0.01). The initial value in Group II was 45.86 +/- 18.86 ng/ml and the final values increased to 117.0% of the initial values, this difference was not significant. The initial value in Group III was 44.48 +/- 21.53 ng/ml and the final values increased to 143.4% of the former. This increase was significant by paired Student's t-test (p < 0.05). The difference in % fluctuations between Group I and Group III was significant by Wilcoxon's test (p < 0.01). These results suggest that the measurement of plasma TM can be useful in the management of DIC.     

Which factors affect high D-dimer levels in the elderly?

To study the age-related changes in plasma D-dimer levels and the effect of atherosclerotic disease and long-term immobilization on haemostasis the elderly, we measured plasma D-dimer levels in 148 subjects aged from 60 to 94 years using an ELISA. We also measured plasma fibrinogen, serum uric acid, total cholesterol, triglycerides, HDL cholesterol, beta-lipoprotein fractions, and apolipoproteins (A-I, A-II, B, E). Plasma D-dimer levels (326 +/- 148 ng/ml) were significantly higher in the healthy elderly subjects than in younger controls (180 +/- 58 ng/ml, p less than 0.01) and increased further with age (r = 0.344, p less than 0.01). D-dimer levels were significantly higher in elderly women than in elderly men (p less than 0.05). The D-dimer level correlated significantly with both the fibrinogen antigen level (r = 0.286, p less than 0.001) and the clotting activity (r = 0.275, p less than 0.01), and also correlated with apolipoprotein E levels. There were no correlations with the other parameters assessed. The D-dimer levels were significantly higher in the elderly subjects with atherosclerotic disease (516 +/- 285 ng/ml) than in healthy elderly subjects (p less than 0.001). Moreover, the levels were even higher in elderly subjects with long-term immobilization (866 +/- 408 ng/ml) than in subjects with atherosclerosis, even after age, sex and underlying diseases were taken into consideration. These results indicate that coagulation and fibrinolysis activity are increased in the elderly, especially those with atherosclerotic disease and that moreover long-term immobilization further accelerates their haemostatic hyperactivity.     

Tissue factor reduction and tissue factor pathway inhibitor release after heparin administration

Elevated plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) and large amounts of monocyte procoagulant activity (PCA) have been documented in unstable angina (UA) patients. In in vitro experiments heparin is able to blunt monocyte TF production by inhibiting TF and cytokine gene expression by stimulated cells and after in vivo administration it reduces adverse ischemic outcomes in UA patients. TF and TFPI plasma levels and monocyte PCA have been investigated in 28 refractory UA patients before and during anticoagulant subcutaneous heparin administration (thrice daily weight- and PTT-adjusted for 3 days) followed by 5000 IU X 3 for 5 days. After 2-day treatment, immediately prior to the heparin injection, TF and TFPI plasma levels [(median and range): 239 pg/ml, 130-385 pg/ ml and 120 ng/ml, 80-287 ng/ml] were lower in comparison to baseline samples (254.5 pg/ml, 134.6-380 pg/ml and 135.5 ng/ml, 74-306 ng/ml). Four h after the heparin injection TF furtherly decreased (176.5 pg/ml, 87.5-321 pg/ml; -32.5%. p<0.001) and TFPI increased (240.5 ng/ml, 140-450 ng/ml; +67%, p<0.0001). After 7-day treatment, before the injection of heparin, TF and TFPI plasma levels (200 pg/ml, 128-325 pg/ml and 115 ng/ml, 70-252 ng/ml) significantly decreased (p<0.05) in comparison to the pre-treatment values. On the morning of the 8th day, 4 h after the injection of heparin TF plasma levels and monocytes PCA significantly decreased (156.5 pg/ml, 74-259 pg/ml and from 180 U/105 monocytes, 109-582 U/10(5) monocytes to 86.1 U/10(5) monocytes, 28-320 U/10(5) monocytes; - 38% and -55% respectively) and TFPI increased (235.6 ng/ml, 152-423 ng/ ml; +70%, p<0.001). In conclusion, heparin treatment is associated with a decrease of high TF plasma levels and monocyte procoagulant activity in UA patients. These actions of heparin may play a role in determining the antithrombotic and antiinflammatory properties of this drug.     

Fibrinolysis and coagulation in patients with infectious disease and sepsis

Sepsis is often associated with hemostatic dysfunction. This study aimed to relate changes in fibrinolysis and coagulation parameters to sepsis and sepsis outcome. Urokinase-type plasminogen activator (u-PA) antigen, tissue-type plasminogen activator (t-PA) antigen and activity, plasminogen activator inhibitor (PAI) type 1 antigen, PAI activity, antithrombin (AT) III activity, and protein C activity were measured in 24 patients suffering from sepsis or septic shock and the results were compared with those observed in 30 non-sepsis patients with severe infectious disease. The u-PA level was markedly increased in plasma of sepsis patients as compared to non-sepsis patients (11.5 +/- 9.4 versus 1.6 +/- 1.5 ng/ml, p less than 0.0001). PAI-1 antigen and t-PA activity showed a significant increase in sepsis patients (320 +/- 390 ng/ml versus 120 +/- 200 ng/ml, and 3.0 +/- 3.6 IU/ml versus 1.0 +/- 0.7 IU/ml, respectively, p less than 0.01). AT III was decreased in sepsis patients (58 +/- 28% in sepsis versus 79 +/- 26% in severe infectious disease, p less than 0.01) as was protein C (30 +/- 18% versus 58 +/- 27%, p less than 0.001). No significant difference was found for t-PA antigen nor for PAI activity. Nonsurvivors of sepsis were distinguished mainly by a high u-PA antigen level and increased t-PA activity. It is concluded that plasma u-PA antigen showed the strongest significant difference, among the parameters evaluated, between sepsis and severe infection. u-PA antigen may be of prognostic value in patients admitted to the medical intensive care unit for severe infectious disease.     

Total tissue factor pathway inhibitor is an independent risk factor for symptomatic paediatric venous thromboembolism and stroke

Tissue factor pathway inhibitor (TFPI) plays an important role in inhibiting tissue factor-induced coagulation by a factor Xadependent pathway of the activated tissue-factor VIIa complex. Decreased values of the latter inhibitor have been recently reported in adult patients with venous thrombosis (VT) or ischaemic stroke (IS). The present case-control study was therefore performed to evaluate whether a decreased TFPI concentration is also involved in paediatric symptomatic thromboembolism (ST). Total TFPI concentrations were measured along with established prothrombotic risk factors six to twelve months after the acute thrombotic onset in 144 Caucasian children aged 0.6 to 18 years (VT: n=80; IS: n=64). The cut-off values defined as age-dependent 10(th) percentiles were obtained from 244 healthy controls. Median (range) values of TFPI were significantly lower in patients compared with control subjects [50.0(20.0-132.3) ng/ml vs. 59.5(25.4-117.4) ng/ml; p-value < 0.0001]. In addition, 42 of the 144 patients (29.2%) compared with 25 of the 244 controls (10.2%) showed TFPI concentrations below the 10(th) age-dependent percentiles. Compared to baseline values 78.6% of children with total TFPI Ag < 10(th) percentiles showed a low response to enoxaparin administration, whereas in children with normal baseline TFPI values 30% show a low TFPI release (p = 0.007). Multivariate analysis adjusted for the presence of established prothrombotic risk factors showed a significantly increased odds ratio (OR) and 95% confidence interval (CI) for patients with ST [OR/CI: 3.8/2.2-6.6; p < 0.0001]. Data shown here give evidence that total TFPI concentrations below the 10(th) age-dependent percentiles independently increase the risk of ST in Caucasian children 3.8-fold.     

Increased levels of plasma tissue factor pathway inhibitor in patients with glioblastoma and intracerebral metastases

Tissue Factor Pathway Inhibitor (TFPI) prevents further participation of Tissue Factor (TF) in the coagulation process by forming a stable quaternary complex of TF-FVIIa-FXa-TFPI. Recently, plasma TFPI level were found to be elevated in patients with malignant disease outside the brain. Therefore the aim of this study was to investigate the TFPI plasma level in patients with primary brain tumors and intracerebral metastases. From May 2000 to December 2001 the total tissue factor pathway inhibitor antigen (TFPI) was preoperatively determined in blood samples of 225 patients with primary or metastatic brain tumors. Tumor histology classified as benign (WHO grade I and II) and malignant (WHO grade III and IV, intracerebral metastases) was correlated to plasma TFPI-levels. Plasma TFPI was significantly higher in patients with malignant tumors including intracerebral metastasis compared to benign tumors (80.1 +/- 34.31 versus 64.3 +/- 25.8 ng ml-1 [p < 0.01; t-test]). To exclude the influence of primary systemic neoplasms with secondary brain metastasis on plasma TFPI-level a subgroup of patients with primary brain tumors (meningioma, astrocytoma, oligodendroglioma and glioblastoma) was separated. In this group TFPI-level was also significantly elevated in patients with malignant (n = 66) (78.6 +/- 29.9) compared to benign brain tumors (n = 127) (64.3 +/- 25.8 ng ml-1 [p < 0.01; t-test]). To the authors' knowledge this is the first study describing the correlation of increased plasma TFPI and malignancy in patient with brain tumors. Further studies are needed to clarify the pathogenic mechanism and the clinical relevance of this phenomenon.     

Changes of plasma coagulation and fibrinolysis in response to mental stress

To study the effects of standardized mental stress (arithmetic and the Stroop color word test) on plasma coagulation and fibrinolysis, blood samples were obtained before, during, and after 20 minutes of mental stress from 10 healthy, non-smoking young males aged 22 to 30 years. Reactions were compared with those observed during physical exercise and infusion of adrenaline. Both von Willebrand factor antigen and factor VIII coagulant activity increased significantly in response to mental stress (95 +/- 28 vs 123 +/- 56%; p less than 0.05 and 125 +/- 54 vs 217 +/- 170%; p less than 0.05, respectively). There was also a significant increase of factor VII coagulant activity (86 +/- 31 vs 108 +/- 51%; p less than 0.05). Furthermore, mental stress caused an activation of the fibrinolytic system with an elevation of tissue plasminogen activator activity and tissue plasminogen activator antigen (0.80 +/- 0.48 vs 1.23 +/- 0.96 IU/ml; p = 0.076 and 4.38 +/- 1.87 vs 5.78 +/- 2.58 IU/ml; p less than 0.01). Fibrinogen concentration increased during stress (1.95 +/- 0.29 vs 2.11 +/- 0.27 g/l; p less than 0.05). Similar but more pronounced responses were observed during exercise and adrenaline infusion. Parallel to the increases in coagulation and fibrinolytic factors there were significant increases in heart rate, and systolic and diastolic blood pressure. It is concluded that mental stress has significant effects on plasma coagulation and fibrinolysis, and that it could thus affect important risk factors for cardiovascular disease.     

Plasma thrombospondin in patients with chronic renal failure, liver disease and splenectomy

Thrombospondin (TSP), is a major constituent of human blood platelet alpha-granules. Stimulation of platelets causes the release of TSP in parallel with other alpha-granule constituents such as beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) but the thrombospondin plasma in vivo half life is significantly greater than beta-TG and PF4. The aim of this study was to assay TSP levels in plasma of patients with chronic renal failure (CRF), liver disease (LD) and following splenectomy. The TSP values were then compared to the patients plasma levels of two traditional markers of platelet activation, beta-TG and PF4, and to fibronectin (FN) and von Willebrand factor (VIII:vWF). Plasma TSP levels (67.6 +/- 16.9 ng/ml) assayed in 14 CRF patients were significantly higher (p less than 0.05) than those measured in 28 donors (55.5 +/- 11.7 ng/ml). No correlation was observed, in CRF patients, between the TSP level and PF4 (2.5 +/- 1.5 ng/ml), beta-TG (131.1 +/- 21 ng/ml), FVIII:vWF (252 +/- 85%), or FN (102 +/- 33%) plasma levels. The TSP plasma level in CRF patients was significantly correlated (p less than 0.02) with that of fibrinopeptide A (4.1 +/- 1.9 ng/ml). Although the beta-TG (23.5 +/- 6.9 ng/ml) and PF4 (2.9 +/- 2 ng/ml) plasma levels in six LD patients were normal, the TSP levels (82.5 +/- 39.1 ng/ml) were significantly increased (p less than 0.01). Thrombospondin plasma levels (77.1 +/- 20.1 ng/ml) in 14 patients having undergone splenectomy were significantly increased (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship between smoking and fibrinolytic system with special reference to t-PA and PA inhibitor

Recently tissue plasminogen activator (t-PA) has been clinically applied to the thrombolytic therapy of myocardial infarction. We investigated relationship between cigarette smoking and fibrinolytic system, namely the plasma level of t-PA antigen, plasminogen activator inhibitor (PAI), and PA activity. Nineteen healthy volunteers were asked to smoke for 10 min. The plasma levels of t-PA antigen, PAI activity, PA activity and catecholamine were measured together with measurement of blood pressure and heart rate before, soon after or 30 min after cigarette smoking. Plasma t-PA antigen after cigarette smoking increased to 8.83 +/- 3.11 ng per ml, significantly higher (p less than 0.005) than 6.35 +/- 1.7 ng/ml before cigarette smoking. Plasma PAI activity after cigarette smoking was 5.52 +/- 2.03 u/ml, significantly higher (p less than 0.05) than 4.18 +/- 1.06 u/ml before smoking. Plasma PA activity after smoking was 6.28 +/- 3.85 u/ml significantly higher (p less than 0.05) than 4. 49 +/- 2.74 u/ml. Furthermore, plasma epinephrine level after smoking increased to 59.1 +/- 52.4 pg/ml (p less than 0.1), compared with 36.2 +/- 22.5 pg/ml before smoking. There was a positive correlation between the rate of increase in plasma t-PA antigen and the rate of increase in plasma epinephrine after smoking. It is suggested that plasma epinephrine was related to the mechanism of increased plasma levels of t-PA in cigarette smoking.     

Imbalances between the levels of tissue factor and tissue factor pathway inhibitor in ARDS patients

INTRODUCTION: To evaluate the pathogenetic role of tissue factor (TF), tissue factor pathway inhibitor (TFPI), and neutrophil elastase in acute respiratory distress syndrome (ARDS), as well as to test the hypothesis that TFPI levels modified by neutrophil activation are not sufficient to prevent TF-dependent intravascular coagulation, leading to sustained systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS), which determine the prognosis of these patients. MATERIALS AND METHODS: The study subjects consisted of 55 patients with trauma and sepsis who were divided into three groups according to the Lung Injury Score. Ten normal healthy volunteers served as control. Plasma levels of TF, TFPI, and neutrophil elastase were measured on the day of injury or the day of diagnosis of sepsis (day 0) and days 1 through 4. The number of SIRS criteria that the patient met and the disseminated intravascular coagulation (DIC) score is determined daily. RESULTS: Patients (15) developed ARDS, 23 were at risk for but did not develop the syndrome, and 17 patients were without risk for ARDS. TF and neutrophil elastase levels in ARDS patients were persistently higher than those in other two groups and control subjects. However, the TFPI levels showed no difference among the three groups, which retained normal or slightly elevated levels compared to the control subjects. DIC scores did not improve and SIRS continued during the study period in patients with ARDS. The ARDS patients showed higher numbers of dysfunctioning organs and associated with poorer outcome than the other two groups. CONCLUSION: Systemic activation of the TF-dependent pathway not adequately balanced by TFPI is one of the aggravating factors of ARDS. High levels of neutrophil elastase released from activated neutrophils may explain the imbalance of TF and TFPI. Persistent DIC and sustained SIRS contribute to MODS, determining the prognosis of ARDS patients.     

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

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

Activation of blood coagulation and fibrinolysis in diabetes mellitus: evaluation by plasma levels of thrombin-antithrombin III complex and plasmin-alpha 2-plasmin inhibitor complex

Diabetes mellitus (DM) is associated with an increased incidence of vascular complications. Abnormalities in the hemostatic system contribute at least in part to the development of vascular disease or atherosclerosis. In order to assess the actual degree of activation of the coagulation and fibrinolytic systems in diabetics, plasma levels of thrombin-antithrombin III complex (TAT) and plasmin-alpha 2-plasmin inhibitor complex (PAP) were measured together with tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) in 18 patients with DM (three patients with type I DM and 15 with type II DM). Mean plasma levels of TAT (2.5 +/- SD 1.2 ng/mL) and PAP (0.9 +/- 1.2 micrograms/mL) were significantly elevated in diabetics as compared with healthy subjects (1.7 +/- 0.3 ng TAT and 0.2 +/- 0.1 micrograms PAP per mL of plasma; p = 0.009 and 0.02, respectively). Plasma antigen concentration of t-PA but not of PAI-1 was also elevated. No difference was found in the levels of these variables between type I and type II diabetics or between patients with and without retinopathy or nephropathy. These findings indicate that continuous activation of coagulation and fibrinolysis actually occurs in the majority of the patients with DM.     

Activation of coagulation and fibrinolysis in patients with arteriosclerosis: relation to localization of vessel disease and risk factors

Activation markers of blood coagulation and fibrinolysis and several fibrinolytic parameters were determined in arteriosclerotic patients to investigate the relation between extension and main localization of vessel disease, risk factors and disturbances within the blood coagulation and the fibrinolytic system. Indications of an increased intravascular fibrin formation and subsequent fibrinolysis were found in peripheral artery disease (PAD) patients but not in coronary artery disease (CAD) patients. Compared with healthy controls PAD patients had elevated TAT (median: 3.2 ng/ml, 1.5-70 vs. 2.1, 1.2-4.7, p less than 0.005) and D-Dimer (median: 365 ng/ml, range 85-2000 vs. 185, 79-360; p less than 0.0001) plasma levels, whereas TAT (2.4, 1.2-13) and D-Dimer (190, 58-1000) levels of CAD patients were in the normal range. No associations were detected between risk factors of arteriosclerosis (hyperlipidemia, diabetes mellitus, cigarette smoking, hypertension) and the plasma levels of the activation markers TAT and D-Dimer. Independent from risk factors PAD and CAD patients had elevated plasma plasminogen activator inhibitor capacity (PAI cap). Our results provide evidence that 1) increased plasma levels of blood coagulation and fibrinolysis activation markers are not related to risk factors of arteriosclerosis but seem to be unspecifically caused by activation processes on arteriosclerotic vessel wall defects, 2) increased plasma PAI cap found in arteriosclerotic patients is a relatively unspecific phenomenon associated with arterial vessel disease.     

Plasma D dimer: a useful marker of fibrin breakdown in renal failure

D dimer and other large fragments produced during the breakdown of crosslinked fibrin may be measured by enzyme immunoassay using monoclonal antibodies. In 91 patients with renal disease and varying degrees of renal dysfunction, plasma D dimer showed no correlation with renal function, whereas FgE antigen, a fibrinogen derivative which is known to be cleared in part by the kidney, showed a significant negative correlation with creatinine clearance. Plasma concentrations of D dimer were, however, increased in patients with chronic renal failure (244 +/- 31 ng/ml) (mean +/- SEM) and diabetic nephropathy (308 +/- 74 ng/ml), when compared with healthy controls (96 +/- 13 ng/ml), and grossly elevated in patients with acute renal failure (2,451 +/- 1,007 ng/ml). The results indicate an increase in fibrin formation and lysis, and not simply reduced elimination of D dimer by the kidneys, and are further evidence of activated coagulation in renal disease. D dimer appears to be a useful marker of fibrin breakdown in renal failure.     

Coagulation factor VII in middle-aged women with and without coronary heart disease

Epidemiological studies of coagulation factor VII as a risk factor for coronary heart disease (CHD), mainly conducted in men, have shown discrepant results. We examined the associations of coagulation factor VII antigen (VIIag) and activated factor VII (VIIa) with manifest CHD in a community-based case-control study of women aged < or =65 years. Mean plasma concentrations of VIIag and VIIa in patients and controls were 443 +/- 10(8) and 418 +/- 89 ng/L (p <0.01) and 5.26 +/- 2.21 and 4.90 +/- 1.65 ng/L (NS), respectively. The odds ratio (OR) for CHD for the highest versus the lowest quartile of VIIag was 1.75 (95% CI, 1.05 to 2.92). The adjusted OR was 0.76 (95% CI, 0.28-1.98) after controlling for other cardiovascular risk factors. The corresponding ORs for VIIa were non-significant. In conclusion, the plasma concentration of VIIa was not significantly increased in a large group of women with precocious CHD, and VIIag levels, although elevated, were not independently associated with manifest disease.     

Determination of plasma protein C inhibitor and of two activated protein C-inhibitor complexes in normals and in patients with intravascular coagulation and thrombotic disease

We developed an ELISA to quantitate complexes of activated protein C (APC) with a major plasma APC inhibitor, alpha 1-antitrypsin (alpha 1AT) in human plasma based on the sandwich principle using two different antibodies directed towards protein C and alpha 1AT, respectively. This ELISA test was specific for APC:alpha 1AT complexes and sensitive to greater than or equal to 150 pg complex. Fifty-one of 56 healthy donors had APC:alpha 1AT complex levels above the detection limit (3 ng/ml) ranging from 4 to 14 ng/ml (mean value +/- SD: 7.6 +/- 2.5 ng/ml). Patients (n = 10) with disseminated intravascular coagulation (DIC) had detectable levels of APC:alpha 1AT complex ranging from 21 to 125 ng/ml (median: 69 ng/ml). Complexes of APC with plasma protein C inhibitor (PCI) were also measured using an ELISA sandwich assay. None of the 30 healthy donors had detectable levels (greater than or equal to 5 ng/ml) of APC:PCI complex, and plasma samples from 9 of 10 DIC patients had detectable concentrations of APC:PCI complex ranging from 10 to 63 ng/ml (median: 22 ng/ml). APC:alpha 1AT complex was detected in 25 of 26 patients with deep venous thrombosis (DVT), with levels ranging from 5 to 136 ng/ml (median: 23 ng/ml), whereas APC:PCI was detected in only 6 DVT patients, with levels between 11 and 105 ng/ml. PCI antigen levels in 70 normals ranged from 56 to 175% (mean +/- SD: 99.1% +/- 24.2%). PCI antigen levels were decreased in DIC patients, in patients with cerebral arterial thrombosis, and in DVT patients undergoing heparin therapy, but not in patients with myocardial infarction. PCI antigen levels were decreased much further in DVT patients receiving heparin compared to those not receiving heparin, showing that heparin therapy is associated with a decrease in PCI levels. The detection in normal subjects and in thrombotic patients of circulating APC:inhibitor complexes supports the view that the protein C pathway is activated during DIC and DVT. Moreover, it emphasizes that both PCI and alpha 1AT are physiologic inhibitors of APC. Thus, measurement of APC complexes may provide sensitive parameters for specific detection of activation of the clotting and protein C pathways.