Elevation of factor VII activity and mass in young adults at risk of ischemic heart disease

Chronic testosterone administration improves cardiac contractility and has a beneficial effect on the haemostatic system by enhancing fibrinolytic activity and inducing hypocoagulation in healthy rats

This study investigated the effects of chronic supraphysiological dose of testosterone propionate administration cardiovascular function in rats from the perspective of haemostatic function including platelet functions, coagulation, and fibrinolysis. Testosterone significantly enhanced cardiac contractility by enhancing LVSP (10%), dp/dt_max (36.7%), dp/dt_min (14.6%) without altering heart rate, diastolic function, and serum lipid profile. While it has no effect on platelets count, thromboxane B2 levels, and platelet aggregation, testosterone significantly enhanced bleeding time and increased circulatory and thoracic aorta mRNA and protein levels of tPA (46.5%, 58.2%, and 74.3%, respectively) and significantly decreased those of PAI-1 (29.3%, 26.4%, and 32.8%, respectively). While there were no significant changes in PT and aPTT, mRNA and protein levels of prothrombin and factor VII were downregulated in the livers of the testosterone-treated rats (57.7% and 64.9%, respectively). Overall, chronic testosterone administration in rats may act as a cardio-protective agent by modulating haemostasis in rats.

Factor VII and incidence of myocardial infarction in a Japanese population: The Jichi Medical School Cohort Study

BACKGROUND

The role of factor VII (FVII) as a risk factor in myocardial infarction (MI) has been the subject of numerous studies. However, it remains uncertain whether the FVII levels are associated with development of MI.

METHODS

The subjects were 4142 men and women whose activated FVII (FVIIa) and FVII coagulant (FVIIc) levels were measured in the Jichi Medical School Cohort Study. Subjects were divided into tertiles by FVIIa and FVIIc levels, and Cox's proportional hazard model was used to calculate hazard ratios (HRs) for MI.

RESULTS

The multivariate-adjusted HRs (95% confidential interval [CI]) for FVIIa in men were 0.67 (0.67-1.78) in tertile 2 (T2), and 0.52 (0.17-1.60) in T3. In women, the multivariate-adjusted HRs (95% CI) were 0.18 (0.02-1.60) in T2, and 0.39 (0.07-2.20) in T3. The multivariate-adjusted HRs (95% CI) for FVIIc in men were 0.54 (0.21-1.36) in T2, and 0.20 (0.04-0.91) in T3. In women, the multivariate-adjusted HRs (95% CI) were 0.44 (0.07-2.85) in T2, and 0.35 (0.06-2.22) in T3. We used T1 as a reference for all measures.

CONCLUSION

Our findings revealed a significant association between low FVIIc level and incidence of MI in men. The FVIIa and FVIIc levels were inversely related to increased MI risk, but did not reach statistical significance. Future studies are needed to confirm this association.

How it all starts: Initiation of the clotting cascade

The plasma coagulation system in mammalian blood consists of a cascade of enzyme activation events in which serine proteases activate the proteins (proenzymes and procofactors) in the next step of the cascade via limited proteolysis. The ultimate outcome is the polymerization of fibrin and the activation of platelets, leading to a blood clot. This process is protective, as it prevents excessive blood loss following injury (normal hemostasis). Unfortunately, the blood clotting system can also lead to unwanted blood clots inside blood vessels (pathologic thrombosis), which is a leading cause of disability and death in the developed world. There are two main mechanisms for triggering the blood clotting, termed the tissue factor pathway and the contact pathway. Only one of these pathways (the tissue factor pathway) functions in normal hemostasis. Both pathways, however, are thought to contribute to thrombosis. An emerging concept is that the contact pathway functions in host pathogen defenses. This review focuses on how the initiation phase of the blood clotting cascade is regulated in both pathways, with a discussion of the contributions of these pathways to hemostasis versus thrombosis.

Interrelationships of Factor VII activity and plasma leptin with insulin resistance in coronary heart disease

OBJECTIVE

An increase of FVII activity (FVIIc) has been proposed to be an independent cardiovascular risk factor. Whether FVII is associated with insulin resistance in coronary heart disease (CHD) is still unknown. We tested the hypothesis that plasma FVII activity and leptin are associated with insulin resistance independently.

METHODS

We studied 130 subjects, of which 65 were CHD subjects and 65 were non-CHD control subjects. Fasting plasma levels of leptin, insulin, glucose, FVIIc activity, fibrinogen, lipid parameters were estimated for all the subjects. Body mass index (BMI), waist circumference (WC) and blood pressure levels were also determined.

RESULTS

We observed significantly raised plasma levels of FVIIc activity, leptin and insulin resistance among the CHD subjects compared to the non-CHD subjects. Raised FVIIc activity levels in CHD were significantly positively correlated with insulin resistance. Raised plasma leptin levels in CHD were correlated with insulin resistance, BMI and WC. Multivariate regression analysis showed that elevated levels of FVII activity in CHD was significantly associated with insulin resistance, independent of dyslipidemia, leptin, blood pressure levels, BMI, WC, gender and age. Furthermore, raised leptin levels in CHD subjects were significantly associated with insulin resistance and BMI, independently of each other and of dyslipidemia, FVIIc, blood pressure levels, WC, gender and age.

CONCLUSION

Raised FVII and leptin levels in CHD patients were independently associated with insulin resistance, this was not observed among the non-CHD subjects.

Interleukin-6, Fibrin D-Dimer, and Coagulation Factors VII and XIIa in Prediction of Coronary Heart Disease

OBJECTIVE

Activated inflammation and activated blood coagulation are believed to increase the risk of coronary thrombosis and are related. We therefore compared plasma IL-6 (a key cytokine in the inflammatory process), fibrin D-dimer (a marker of fibrin turnover), and coagulation factors VII and XIIa (initiators of extrinsic and intrinsic blood coagulation, respectively) as predictors of coronary risk in the West of Scotland Coronary Prevention Study of pravastatin in men with hypercholesterolemia.

METHODS AND RESULTS

485 men who had had a coronary event (nonfatal myocardial infarction, death from coronary heart disease, or revascularization) were matched for age and smoking status with 934 controls. Baseline IL-6 and D-dimer were strong univariate predictors of coronary risk (relative risk in the highest quintile approximately twice that in the lowest quintile) and were associated with each other and with C-reactive protein. On multivariate analyses, D-dimer retained a significant association with coronary risk (relative risk, 1.86; 95% CI, 1.24 to 2.80), whereas IL-6 (1.47; 0.95 to 2.28) and C-reactive protein (1.33; 0.85 to 2.08) did not. Neither factor VII nor factor XIIa antigens were predictors of coronary events.

CONCLUSIONS

Fibrin D-dimer may be a stronger predictor of coronary risk than inflammatory markers, perhaps through its ability to stimulate monocyte release of IL-6.

Dietary fatty acids, hemostasis, and cardiovascular disease risk

The cause of many myocardial infarctions is occlusive thrombosis, or a blood clot that stops blood flow in a coronary artery. Hemostasis involves a complex system of factors, which normally form and degrade blood clots, that work within a delicate balance. Emerging evidence suggests that some hemostatic factors, including factor VII, fibrinogen, and plasminogen activator inhibitor-1, are associated with increased risk for cardiovascular disease (CVD). Accumulating evidence suggests a relationship between dietary fatty acids and emerging hemostatic CVD risk factors, although much of this evidence is incomplete or conflicting. Dietary supplementation with marine n-3 fatty acids prolongs bleeding time and may decrease risk for thrombosis. Factor VII coagulant activity modestly decreases with reductions in saturated fatty acid (SFA) intake and thereby may contribute to the beneficial effects of low SFA diets. Large triglyceride-rich particles formed during postprandial lipemia can support the assembly and function of coagulation complexes and seem to play a role in the activation of factor VII, and thus may partially explain increased CVD risk associated with increased postprandial triglyceridemia. As our understanding of the role of dietary fatty acids and hemostasis evolves, it is likely that we will be able to make specific dietary recommendations to further decrease CVD risk. At this juncture, however, increasing marine n-3 fatty acids and decreasing certain SFAs are leading strategies to reduce hemostatic CVD risk factors. An array of dietary strategies that target multiple CVD risk factors could have a greater impact on CVD than a single risk factor intervention strategy.

R353Q Polymorphism, Activated Factor VII, and Risk of Premature Myocardial Infarction in Japanese Men

BACKGROUND

The association between myocardial infarction (MI) and the R353Q polymorphism of the Factor VII (FVII) gene, which reportedly influences FVII concentrations, activated Factor VII (FVIIa), or FVII antigen (FVIIag), remains controversial.

METHODS AND RESULTS

The present case - control study in 127 Japanese men with their first MI at or before 45 years of age and 150 matched healthy controls was designed to clarify this association in premature MI. R353Q polymorphism was determined by polymerase chain reaction, and plasma concentrations of FVIIa and FVIIag were assayed. The distribution of the RR, RQ, and QQ genotypes with respect to R353Q polymorphism was 117, 10, and 0 in the patients, and 131, 17, and 2 in the controls. The Q allele was negatively associated with premature MI (odds ratio =0.41, p=0.038). The plasma concentration of FVIIa was slightly higher in patients (55.1+/-40.9 U/L) than in controls (44.8+/-20.2 U/L), but not significantly (p=0.078); the plasma concentration of FVIIag did not differ between patients (88.7+/-15.7%) and controls (87.0+/-9.0%) (p=0.557). Plasma FVIIa concentrations were influenced by R353Q polymorphism (p<0.001).

CONCLUSIONS

The Q allele may be protective against premature MI.

Angiotensin-converting enzyme insertion/deletion genotype is associated with the activities of plasma coagulation factor VII and X independent of triglyceride metabolism

BACKGROUND

The D allele of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and coagulation activity play important roles in cardiovascular events, however, the precise association between these two risk factors remains unclear.

METHODS

We identified the ACE I/D genotype and measured the plasma coagulation factor VII and X (FVII and FX) activities and serum lipids in 172 patients (110 men and 62 women, mean age 56.7+/-13.3 years) undergoing coronary angiography.

RESULTS

The frequency of the D allele was significantly higher in those with a history of myocardial infarction (MI) than in those with normal coronary arteries, but there was no significant association between FVII and FX activities and the stage of coronary disease. Plasma coagulation factor VII and FX activities were significantly lower in the DD genotype (n=42) than in the II genotype (n=67, P<0.001 and P<0.001, respectively) or the ID genotype (n=63, P<0.01 and P<0.05, respectively). The association of the ACE D allele with lower activities of FVII and FX was also seen in patients with coronary artery disease (CAD). There was a significant association between serum triglyceride levels with FVII and FX, but not with the ACE I/D genotype.

CONCLUSION

We concluded that the ACE I/D polymorphism may contribute more to the onset of MI than the activities of FVII and FX and that the ACE D allele might be associated with lower plasma activities of FVII and FX. The potential link between ACE I/D polymorphism and the plasma activities of FVII and FX is probably independent of triglyceride metabolism.

Polymorphisms in coagulation factor genes and their impact on arterial and venous thrombosis

Arterial and venous thromboses, with their clinical manifestations such as stroke, myocardial infarction (MI), or pulmonary embolism, are the major causes of death in developed countries. Several studies in twins and siblings have shown that genetic factors contribute significantly to the development of these diseases. Since the advent of molecular genetics in medicine, it has been a focus of interest to elucidate the role of mutations in various candidate genes and their impact on hemostatic disorders such as arterial and venous thromboses. In this article, we review the current knowledge of the contribution of polymorphisms in coagulation factors to the development of thrombotic diseases. We show that in arterial thrombosis, results are controversial. Only for factor XIII 34Leu a protective effect on the development of myocardial infarction has been demonstrated in several studies. No other single polymorphism in a coagulation factor could be confirmed as a relevant risk factor, although there is evidence for a role of factor V Arg506Gln, factor VII Arg353Gln, and vWF Thr789Ala polymorphisms in patient subgroups. Further studies will be necessary to confirm the value of testing for genetic polymorphisms in arterial thrombosis. A large body of data is available on the role of factor V Arg506Gln and the prothrombin G20210A mutation in venous thrombosis. Some papers already recommend diagnosis and treatment strategies. We will discuss these recent publications on venous thrombosis in our review.

Association of factor VII levels with inflammatory parameters in hypercholesterolemic patients

Inflammatory markers have been demonstrated to be associated with increased risk of cardiovascular events. In this setting, C-reactive protein (CRP) was shown to add predictive value to cholesterol levels. We investigated hypercholesterolemic patients and related their inflammatory variables and their coagulation state focusing on factor VII, a coagulation protein which plays an established role in thrombogenesis. We examined the relationship between factor VII clotting activity (FVIIc), FVII antigen (FVIIAg) and activated FVII (FVIIa) levels against CRP, interleukin-6 soluble receptor (IL-6sR), P-selectin, soluble intercellular adhesion molecule-1 (ICAM-1) and transforming growth factor-beta(1) (TGF-beta(1)), in fifty-eight hypercholesterolemic subjects. Patients were subjected to 6-8 weeks of lipid lowering treatment with diet or diet plus pravastatin (40 mg/day). Univariate analysis showed that FVII levels were positively associated with CRP (FVIIAg: r=0.56, P<0.0001; FVIIc: r=0.57, P<0.0001; FVIIa: r=0.39, P<0.001) and IL-6sR (FVIIAg: r=0.59, P<0.0001; FVIIc: r=0.52, P<0.0001; FVIIa: r=0.47; P<0.001). CRP was still correlated, at the baseline, with FVIIAg and FVIIc levels after multiple stepwise regression analysis (FVIIAg: P<0.0001; FVIIc: P<0.0001, respectively) and with FVIIAg at the end of lipid lowering treatment (P<0.0001). Our data indicate that the FVII level is independently associated with inflammatory variables and suggest their pathophysiological link in hypercholesterolemic patients.

Statin therapy in acute coronary syndromes: mechanistic insight into clinical benefit

Randomized trials have established that statin treatment reduces coronary events in primary prevention and in patients with stable coronary artery disease. In unstable coronary artery disease, however, the pathophysiological background is distinct, and the potential benefits of statin therapy have not been evaluated until recently. Data from animal models and clinical studies indicate that statin treatment can influence a spectrum of molecular and cellular mechanisms that are intimately related to the pathogenesis of acute coronary syndromes; these include the reduction of circulating levels of atherogenic lipoproteins (very low density lipoprotein, very low density lipoprotein remnants, intermediate density lipoprotein, and low density lipoprotein) and thus of arterial lipid deposition and the attenuation of inflammation, modulation of thrombogenesis and thrombolysis, improvement of endothelial dysfunction, and reduction of ischemia/reperfusion injury. Indeed, findings from prospective and observational studies have demonstrated that statin treatment significantly improves clinical outcome after acute coronary syndromes. Therefore, early initiation of statin therapy after an acute coronary event not only enhances adherence to treatment but also preempts the occurrence of new events. In this review, we discuss recent important developments in our knowledge of the clinical evidence of the beneficial effects of early statin therapy in acute coronary syndromes and the biological mechanisms that underlie them.

Interaction of hemostatic genetics with hormone therapy: new insights to explain arterial thrombosis in postmenopausal women

Genetic variants of key hemostatic mediators increasingly have been proposed as risk factors for atherothrombosis. The Hormone and Estrogen/Progestin Replacement Study group recently reported that the initiation of estrogen replacement in postmenopausal women with known coronary heart disease is associated with an early increase in cardiovascular events. A putative genetic susceptibility factor has been proposed a potential mediator of this increased event risk. This review outlines the recent literature to support the premise for this important proposal. Genetic profiling has great potential to improve the safety and efficacy of individualized pharmacotherapy in postmenopausal women and other at-risk populations for the prevention of cardiovascular disease.

Expression of factor VII in the liver of patients with liver disease: correlations with the disease severity and impairment in the hemostasis

Factor VII (FVII) plasma levels in patients with liver disease may be below the normal range. However, no data are available on FVII expression in liver biopsies from patients with liver diseases other than cirrhosis. We have analyzed the expression of FVII by in situ hybridization in liver biopsies from 50 patients in comparison with the procoagulant activity of FVII, and with the plasma levels as activated FVII (FVIIa) and FVII antigen. The level of FVIIa was significantly lower in stage 4 liver fibrosis patients than in the remaining ones (P < 0.05). The percentage of hepatocytes expressing FVII was significantly lower in stage 4 liver fibrosis patients (4.1+/-1.3%) than in stage 3 (22.7+/-6.1%), stage 2 (31.5+/-6.1%), stage 1 (43.7+/-8.2%) and stage 0 patients (63.8+/-4.4%) (P < 0.001). These percentages correlated inversely in a statistically significant way with the histological activity index and the liver function tests. We have demonstrated that the FVIIa plasma levels in patients with chronic liver disease other than cirrhosis may be below the normal range in the absence of blood coagulation impairment. The percentage of hepatocytes expressing FVII decreases as the severity of liver damage increases.

Serum lipids and regulation of tissue factor-induced coagulation in middle-aged men

Formation of an occlusive thrombus by exposure of tissue factor (TF) to circulating blood and subsequent triggering of coagulation by TF-activated factor VII (FVIIa) complexes on ruptured atherosclerotic plaques is thought to be a key event in myocardial infarction. Tissue factor pathway inhibitor (TFPI) is a potent inhibitor of TF-induced coagulation in which the anticoagulant function most probably is restricted to free TFPI in human plasma. The present study was undertaken to assess the interrelations between serum lipids and components of TF-induced coagulation in 234 apparently healthy men aged 36-56 years recruited from the general population. Plasma free TFPI antigen (Ag) was positively correlated (P < .001) with total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein B (apoB-100), fibrinogen, total amount of FVII (FVIIam), coagulation activity of factor VII (FVIIc), and FVIIa. The significant predictors for free TFPI Ag were total cholesterol, triglycerides, fibrinogen, FVIIc, and age, which explained 33% of the plasma variation in free TFPI Ag assessed by multiple regression analysis. A highly significant (P < .0001) linear trend for increase in atherogenic lipids (i.e., total cholesterol and triglycerides), FVII (i.e., FVIIc and FVIIa), and fibrinogen across quartiles of TFPI Ag was demonstrated after adjustment for confounders. These findings may indicate a compensatory increase in plasma free TFPI with lipid and hemostatic risk factors for atherothrombotic diseases in healthy middle-aged men.

[Coagulant activity of factor VII (FVIIc) in the elderly with ischemic heart disease]

BACKGROUND

The coagulant activity of factor VII increases with age and is a risk factor in middle aged subjects. Its role in elderly people is still unknown. The aim of this study was to evaluate whether or not FVIIc is a risk factor in such population.

PATIENTS AND METHOD

STUDY DESIGN

cases and controls study. The group of cases consisted of 79 subjects fulfilling the following criteria: a) age between 65 and 85 years, and b) admission in the Valle de los Pedroches Hospital of Pozoblanco (Córdoba, Spain) due to a myocardial infarction and/or unstable angina, 2 or 6 months before their enrollment. The control group consisted of 81 subjects of similar age, chosen at random from the municipal registry, and excluding those with coronary heart disease. Factor VIIc was measured by conventional methods. Plasma samples were diluted with deficient plasma in FVIIc, and coagulation times were measured after adding thromboplastin and calcium. The measures were compared with a <<control>> plasma and the results were presented as a percentage.

RESULTS

There were no significant differences in the FVIIc between cases (118.3 [SD 22.2]) and controls (116.5 [24.4]; p = 0.630) in the total group. When classified according to their age, it was observed that within the group of more than 75 years old, cases had a higher FVIIc than controls (124.1 [18.2] vs 113.3 [23.5]; p < 0. 05). When the classification was carried out according to sex, male presented similar results than the total group. Bivariable analysis showed, in subjects with coronary diseases, that FVIIc was related to total cholesterol, cLDL, apoprotein B, body mass index, HbA1c, and age. Factors related to FVIIc in the multivariable analysis were basal glucose serum level, body mass index; cHDL was negatively related.

CONCLUSIONS

FVIIc is higher in very old subjects with coronary diseases so it may be a significant coronary risk factor in this age group.

Plasma concentrations of blood coagulation factor VII measured by immunochemical and amidolytic methods

Ever since the coagulant activity of blood coagulation factor VII (FVII:C) was identified as a risk indicator of cardiac death, a large number of studies have measured FVII protein concentrations in plasma. FVII protein concentrations are either measured immunologically with an ELISA method (FVII:Ag) or estimated with an amidolytic method (FVII:Am). We have investigated whether FVII:Am is a valuable alternative to FVII:Ag. FVII:Ag and FVII:Am were measured in 147 plasma samples from blood donors, patients on oral anticoagulant therapy, postmenopausal women on hormone replacement therapy, in postprandial plasma, in cold activated plasma and in FVII deficient plasma. There was a positive correlation (r=0.96) between FVII:Ag and FVII:Am with slightly but significantly higher values for FVII:Ag (FVII:Ag= 106 U/ml and FVII:Am=100 U/ml; p <0.001). A significant correlation (r=0.93) was still observed after omitting the data from patients on oral anticoagulant therapy, with mean values of 113 U/ml for FVII:Ag and 110 U/ml for FVII:Am (p < 0.01). In a linear regression analysis, the intercept (alpha=-21.50) was different from zero (p < 0.0001) and the slope (beta=1.16) was different from 1.0 (p < 0.001). Only a few points (3.1%) in a difference plot were present outside the expected 95% interval calculated from the analytical imprecision of the two methods. Therefore, we consider the amidolytic method an acceptable alternative to the ELISA method when analysing citrated plasma samples containing only enzymatically functional FVII protein, but the results cannot be directly transferred from one method to the other.

Diet and hemostatic factors

The coagulation, fibrinolytic, and platelet activating systems are complex and interact extensively, and with other systems such as inflammation. Key reactions often require biomembranes, suggesting that dietary lipids, to the extent that they influence membrane composition, may have important regulatory roles. Also, recent evidence suggests that both postprandial and fasting lipoproteins may be associated with either factor levels or activation state or both. This issue has added importance because several hemostatic and fibrinolytic factors are known CVD risk factors. Although there are associations between fasting lipid levels and several coagulation and fibrinolytic factors, the mechanisms are unclear, as are the implications for intervention. In general, postprandial lipids are at least somewhat procoagulant because they activate factor VII. It remains to be demonstrated, however, that this postprandial activation has important clinical correlates. Dietary supplementation with marine omega-3 fatty acids does prolong the bleeding time and may decrease thrombotic potential; however, other than this, little is known about the direct effects of dietary fatty acids on hemostatic and fibrinolytic activities. Much work is needed in carefully controlled studies to expand our knowledge in this important area.

Changes in levels of factor VII and protein S after acute myocardial infarction: effects of low-dose warfarin

Persistent coagulation activity after an acute myocardial infarction may increase the risk of reinfarction. We prospectively investigated the effects on plasma coagulation of a low, fixed dose of warfarin in combination with aspirin after myocardial infarction. We also evaluated the influence of coagulation activity on clinical outcome. Plasma samples from 97 patients, randomised to 1.25 mg of warfarin daily in combination with 75 mg of aspirin or aspirin alone were drawn 4 days, 1 month, and 6 months after myocardial infarction. Patients receiving warfarin had a greater reduction in factor VII coagulation activity (FVII:C) after 6 months: 0.18 vs. 0.06 U/mL,(95% CI, 0.02-0.22), whereas no differences were seen in levels of protein C, protein S, or prothrombin fragment 1+2. In the acute phase, the level of free protein S was lower than after 6 months in both groups: 25.6 vs. 28.8% (95% CI, 4.19--2.35). Cardiovascular mortality, reinfarction, and stroke were evaluated after 4 years (median). In a survival analysis, every 0.1 U/mL increase in the level of FVII:C1 month after myocardial infarction was associated with an 15% increase in risk of cardiovascular events (95% C1, 1.01-1.30). Warfarin at 1.25 mg daily reduces FVII:C but not systemic thrombin generation measured as prothrombin fragment 1 +2. Low levels of the anticoagulant protein S may contribute to a procoagulant state.

Genetic determinants of arterial thrombosis

This chapter describes examples of genetic variation involved in the function or regulation of a number of haemostatic proteins involved in the thrombotic process. In each case, the data suggest associations between genotype and disease and, particularly in the case of fibrinogen, PAI-1, Factor VII and Factor XIII, there is interaction between genotype and environment in determination of the relevant plasma level, providing a possible explanation for the differential response of individuals to their environment.

The relationship of fibrinogen and factors VII and VIII to incident cardiovascular disease and death in the elderly: results from the cardiovascular health study

Little is known about the prospective associations of fibrinogen, factor VII, or factor VIII with cardiovascular disease (CVD) and mortality in the elderly. At baseline in the Cardiovascular Health Study (5888 white and African American men and women; aged >/=65 years), we measured fibrinogen, factor VIII, and factor VII. We used sex-stratified stepwise Cox survival analysis to determine relative risks (RRs) for CVD events and all-cause mortality (up to 5 years of follow-up), both unadjusted and adjusted for CVD risk factors and subclinical CVD. After adjustment, comparing the fifth quintile to the first, fibrinogen was significantly associated in men with coronary heart disease events (RR=2.1) and stroke or transient ischemic attack (RR=1.3), and also with mortality within 2.5 years of follow-up (RR=5.8) and later (RR=1.7). Factor VIII was significantly associated in men with coronary heart disease events (RR=1.5) and mortality (RR=1.8), and in women with stroke/transient ischemic attack (RR=1.4). For both factors, values were higher in those who died, whether causes were CVD-related or non-CVD-related, but highest in CVD death. Factor VII exhibited associations with incident angina (RR=1.44) in men and with death in women (RR, middle quintile compared with first=0.66). However, in general, factor VII was not consistently associated with CVD events in this population. We conclude that, if confirmed in other studies, the measurement of fibrinogen and/or factor VIII may help identify older individuals at higher risk for CVD events and mortality.

A prospective study on the effects of reformulated 2-rod Norplant implant on haemostasis after five years of use

OBJECTIVE

To evaluate the long-term effects of the new reformulated 2-rod Norplant implant on haemostasis in a prospective group of subjects who have completed 5 years of use.

METHODS

Data from 11 women who have completed 5 years' use of the new reformulated 2-rod subdermal implant from the original 16 women who were recruited and randomized to receive this new improved implant in a comparative study were analysed. Clinical assessment and serial blood sampling were done prior to insertion of implant and after 1, 3, 12, 18, 24, 36, 48 and 60 months of implant use. Each subject served as its own control and Analysis of Variance with Student-Newman-Kuels test was used for statistical analysis. The following parameters were determined: plasminogen activators (t-PA, u-PA), plasminogen activator inhibitor-1 (PAI-1), D-dimer, beta-thromboglobulin (beta-TG), thrombin-antithrombin (TAT)-complex, fibrinogen, Factor VII, platelets, haematocrit and haemoglobin levels.

RESULTS

No significant change was observed for t-PA levels in prolonged implant use. u-PA antigen showed a significant decrease whilst D-dimer were significantly elevated at only 24 months of implant use compared to pre-implant level. PAI-1 levels were not significantly changed but fibrinogen and FVII levels increased at 36 months and 42 months of use with enhanced platelet activation shown by beta-TG levels at 24 months. Platelet numbers were not affected by prolonged implant use. Haemoglobin concentration and haematocrit level showed significant fluctuations and then return to pre-implant level by 54 and 60 months.

CONCLUSION

Enhanced fibrinolysis with platelet activation at 24 months of implant use were seen during the 60 months of 2-rod reformulated Norplant implant use. Hypercoagulable state was not observed although fibrinogen and FVII levels remain above the pre-implant levels as coagulation activation was not enhanced. The increased haemoglobin and haematocrit levels seen indicate enhanced bone marrow activity. There was no association between the use of reformulated 2-rod Norplant implant over 60 months of use and prothrombotic state.

Two Common Functional Polymorphisms in the Promoter Region of the Coagulation Factor VII Gene Determining Plasma Factor VII Activity and Mass Concentration

Recent studies have provided evidence for associations between common polymorphic markers in the coagulation factor VII (FVII) gene and plasma FVII levels. Here we describe two common, nonrelated, functional polymorphisms in the promoter region of the FVII gene, a G to T substitution at position −401 and a novel G to A substitution at position −402. Both polymorphisms strongly influence the binding properties of nuclear protein(s). The rare −401T allele is associated with a reduced basal rate of transcription of the FVII gene in human hepatoblastoma cells and with reduced plasma concentrations of total FVII (VIIag) and fully activated FVII molecules (VIIa). In contrast, the rare −402A allele confers increased transcriptional activity and is associated with increased plasma FVII levels. Together, the two polymorphisms explained 18% and 28% of the variation in VIIag and VIIa, respectively, in a group of 183 healthy, middle-aged men. It is concluded that these polymorphisms are important for the regulation of the plasma levels of FVII and that they are likely to be useful genetic markers to resolve the issue of whether a causal relationship exists between FVII levels and risk of coronary heart disease.

Effects of lipids and lipoproteins on thrombosis and rheology

Atherosclerotic plaque rupture and erosions precipitate thrombus formation and may lead to an acute ischemic syndrome. Lipids and lipoproteins modulate the expression and/or function of thrombotic, fibrinolytic and rheologic factors, and thereby influence hemostasis and potential tissue damage resulting from vascular injury. Triglyceride-enriched lipoproteins are accompanied by elevations in factor VII clotting activity, plasminogen activator inhibitor (PAI-1) and viscosity of blood and plasma. Low density lipoprotein (LDL) promotes platelet activation and tissue factor expression and LDL levels correlate with levels of vitamin K dependent coagulation factors and fibrinogen. Conversely, LDL inhibits tissue factor pathway inhibitor (TFPI) which limits activation of the extrinsic coagulation pathway. High density lipoprotein (HDL) has anti-atherothrombotic properties that result from inhibition of platelet and erythrocyte aggregation, reduced blood viscosity and suppression of tissue factor activity and PAI-1 activity and antigen levels. The effects of lipids and lipoproteins on hemostasis and rheology may have important implications for the clinical sequelae following plaque disruption and erosion.

Association of factor VII protein concentration with lifestyle factors

Several studies have demonstrated that changes in fasting levels of factor VII coagulant activity (FVII:C), a thrombotic risk marker, are due to changes in FVII protein concentrations (FVII:Ag). Consequently, studies on FVII now often include measurements of FVII:Ag. The present cross-sectional study examined the association between several behavioural variables (body mass index, physical activity, tobacco or alcohol consumption) or physiological variables (total cholesterol, HDL-cholesterol, triglycerides, glucose, insulin, fibrinogen, resting pulse, systolic blood pressure, bleeding time) and FVII:Ag in 439 51-y-old Danish men. In the multivariate analyses, body mass index (BMI), low physical activity, total cholesterol, short bleeding time, and insulin showed an independent positive association with FVII:Ag. The strongest independent association with FVII:Ag was found for total cholesterol. These results suggest that blood lipids are major determinants of FVII:Ag, but that other lifestyle factors such as insulin, BMI and physical activity can also influence FVII:Ag. Furthermore, the association between FVII:Ag and bleeding time suggests an effect of FVII or the FVII pathway on primary haemostasis.

Coagulation factor VII and the risk of coronary heart disease in healthy men

Numerous investigations have demonstrated the role of thrombus formation in the pathogenesis of coronary heart disease (CHD). A tendency to thrombosis may also be indicated by elevated levels of coagulation factor VII clotting activity (FVIIc). Significant associations of FVIIc with increased coronary risk, however, have been found only in the Northwick Park Heart Study. Here we present the results of the 8-year follow-up of FVIIc measurements in 2780 healthy men of the Prospective Cardiovascular Münster study. In the study population (age at entry, 49.3 +/- 6.1 years, mean +/- SD), 130 CHD events occurred during follow-up. FVIIc was significantly higher in subjects with coronary events than in those without (112.4 +/- 20.1% vs 108.7 +/- 21.4%, P = .023). Compared with individuals without coronary events, FVIIc was not significantly higher in men with nonfatal events (111.7 +/- 20.4%; P = .196, n = 93), but there was a tendency toward higher FVIIc activity in subjects with fatal events (114.6 +/- 19.5%; P = .076, n = 37). In the multiple logistic regression analysis, we did not find FVIIc to be an independent risk factor for CHD, and the significance of FVIIc disappeared after total cholesterol, LDL-cholesterol, and triglycerides were taken into account. The increase in the number of CHD events through higher levels of FVIIc was more pronounced in the presence of additional cardiovascular risk factors: smoking; myocardial infarction events in family; angina pectoris; high levels of fibrinogen, total cholesterol, LDL cholesterol, and triglycerides; and a low level of HDL cholesterol. We conclude that FVIIc is a risk factor for CHD, especially in the presence of additional risk factors, and must be taken into account when assessing cardiovascular risk in men.

A Novel Specific Immunoassay for Plasma Two-Chain Factor VIIa: Investigation of FVIIa Levels in Normal Individuals and in Patients With Acute Coronary Syndromes

We report the development of an enzyme-linked immunosorbent assay (ELISA) that is specific for factor VIIa (FVIIa). This assay uses a neoantigen specific capture antibody directed to the amino acid peptide sequence N terminal to the FVII cleavage activation site. The antibody exhibits ∼3,000-fold greater reactivity to FVIIa than FVII on a molar basis. Experiments using plasma with added (exogenous) human FVIIa gave quantitative recovery in the ELISA over a range of 0.20 to 3.2 ng/mL of FVIIa. The intra- and inter-assay coefficient of variation (CVs) of the ELISA are 4.5% and 9.8%, respectively. The ELISA shows excellent correlation (r = .99) with a functional assay (using recombinant soluble tissue factor) in detecting FVIIa added to plasma over the range 0.05 to 18.0 ng/mL. However, a major discrepancy exists between the two assays when normal endogenous plasma concentrations of FVIIa are measured. Using normal plasma (n = 14) the functional assay reported 3.10 ± 0.30 ng/mL (mean ± SE) whereas only 0.025 ± 0.010 ng/mL was detected in the same samples by the immunoassay. Patients (n = 43) presenting with acute coronary syndromes (myocardial infarction and unstable angina) exhibited elevations (P < .05) in immunologically detected FVIIa, 0.093 ± 0.013 ng/mL (mean ± SE) compared to patient controls (n = 20) contemporaneously admitted with noncardiac chest pain, 0.048 ± 0.007 ng/mL (mean ± SE). These elevations in the acute coronary syndromes were accompanied by increased (P < .05) and correlating prothrombin fragment F1 + 2 levels (Spearman correlation coefficient rs = .4, P < .01), demonstrating that thrombin generation is certainly associated with, and may even be caused by, extrinsic pathway activation.

Factor VII, cholesterol, and triglycerides. The CARDIA Study. Coronary Artery Risk Development in Young Adults Study

Cross-sectional studies have shown that factor VII coagulant activity (VIIc) is positively associated with plasma total cholesterol (TC), LDL cholesterol, and triglycerides (TG) as well as body mass index (BMI) and diastolic blood pressure. To determine whether changes in VIIc parallel changes in coronary risk factors over a period of 2 years, we examined data from 1514 participants in the Coronary Artery Risk Development in Young Adults Study (CARDIA), an ongoing investigation of lifestyles and evolution of cardiovascular risk factors. Subjects were 23 to 35 years old at the year 5 examination. Cross-sectional analyses at these examinations showed that VIIc was positively correlated (P < .001) with TC and TG in all race/sex groups except for TC in black women at the year 5 examination. Changes in VIIc over the 2-year period were correlated positively with changes in TC in all except black men and TG in all groups; the association of VIIc change with change in TC and TG was reduced only slightly with adjustment for age and BMI at year 5 and 2-year change in BMI. To determine whether the higher levels of VIIc in subjects with higher lipid values were due to activation of the factor or to an increase in the concentration of the factor VII clotting protein, we measured factor VII antigen (VIIag) in a randomly selected subsample of 223 subjects at the year 7 examination. In all sex/race groups, VIIag correlated with VIIc (r = .69 to 0.81). After adjustment for sex and race, the partial correlation coefficient between TG and VIIc was .28 (P = .0001); between TG and VIIag, .35 (P = .0001); between TC and VIIc, .39 (P = .0001); and between TC and VIIag, 0.43 (P = .0001). No associations were observed between lipid levels and the ratio of VIIc to VIIag. We conclude that the raised VIIc with higher lipid levels occurs in blacks as well as whites, in men and women, persists over time, and represents a true increase in the plasma concentration of this clotting factor.

Postprandial elevation of activated factor VII in young adults

The Northwick Park Heart Study found that factor VII (FVII) activity was a risk factor for ischemic heart disease, and other studies based on indirect assays of activated factor VII (FVIIa) found an elevation of FVIIa postprandially. We hypothesized that postprandial elevation of FVIIa would produce intermittent activation of factor X to Xa and, subsequently, prothrombin to thrombin. We chose to study postprandial activation of coagulation with a new assay specific for FVIIa that uses soluble tissue factor and with a prothrombin fragment 1 + 2 (F1 + 2) assay to detect the activation of prothrombin by factor Xa. We fed a high-fat breakfast (30 g/m2) to 30 healthy volunteer subjects (30.8 +/- 9.8 years; range, 20 to 49 years) on no medication. Fasting blood samples were collected for FVIIa, FVII antigen (FVIIag). and F1 + 2 as well as triglycerides and total and HDL cholesterol. A significant difference was found between fasting (2.82 +/- 1.49 ng/mL. mean +/- SD) and 6-hour postprandial (3.45 +/- 2.08 ng/mL) FVIIa levels (P < .004); FVIIag did not change significantly (mean, 0.89 U/mL fasting and 0.90 U/mL at 6 hours). In contrast, F1 + 2 levels were slightly lower 6 hours postprandially than fasting (median, 0.39 versus 0.44 nmol/L, P < .02). Four-hour postprandial triglyceride levels correlated significantly (p = 0.51, P < .02) with 6-hour postprandial FVIIag but not with 6-hour postprandial FVIIa. Postprandial F1 + 2 levels (at 6 hours) correlated significantly (p = 0.39, P < .04) with fasting FVIIag levels but not with 6-hour postprandial FVIIa levels. Thus, the basal FVIIag level, in the fasting state, may be involved in control of the generation of F1 + 2. We found a postprandial increase in FVIIa levels after a dietary fat load but did not find a concomitant postprandial burst of activation of factor X and prothrombin as measured by F1 + 2. Further studies are to test whether postprandial FVIIa generation leads to enhanced activation of coagulation.

The effects of reformulated 2-rod Norplant implant on hemostasis after three years

Prolonged use of reformulated and the original 2-rod Norplant implants showed similar changes in most hemostatic parameters studied. Raised hemoglobin concentration and hematocrit values with not enhanced platelet activation or significant changes in platelet numbers were seen. Factor VII showed an increase from 18 months compared to the first 12 months of original Norplant implant use, while with reformulated Norplant implant, the level at 36 months was significantly higher than the first 24 months of implant use. Fibrinogen levels were significantly elevated by 36 months of both implant use. No evidence of enhanced activation of coagulation, fibrinolysis/inhibitor were observed during prolonged implant use. Overall, no significant changes in tissue plasminogen activator (t-PA) levels were observed but urokinase-like plasminogen activator (u-PA) levels were significantly reduced, indicating no enhancement of tissue breakdown. Plasminogen activation inhibitor (PAI-1) antigen levels were significantly reduced from 12 to 36 months with original Norplant implant use compared to the pre-insertion levels, while a nonsignificant decreased trend was seen with prolonged reformulated Norplant implant use. The increased levels of fibrinogen and FVII at the end of 36 months of implant use require further observation as these factors are known markers of hypercoagulation and associated with increased arteriosclerotic and cardiovascular risks. This study is on-going to evaluate the effects of levonorgestrel-containing subdermal reformulated Norplant implants on hemostasis after five years of use.

Fibrinogen and factor VIII, but not factor VII, are associated with measures of subclinical cardiovascular disease in the elderly. Results from The Cardiovascular Health Study

No studies have examined the associations of coagulation factor levels with measures of subclinical cardiovascular disease (CVD) in the elderly. The Cardiovascular Health Study (CHS) is a prospective, population-based cohort study of CVD in persons older than 65 years. At the baseline examination, we measured fibrinogen, factor VII, and factor VIII levels in 5024 of the 5201 participants of the CHS and examined the associations of these coagulation factors with measures of subclinical CVD in a cross-sectional analysis. Subclinical CVD measures were based on electrocardiography, carotid ultrasonography, echocardiography, and ankle-arm blood pressure measurements (AAI). For analyses, we used the full cohort as well as two mutually exclusive subgroups: those with prevalent clinical CVD at baseline and those without. Fibrinogen and to a lesser extent factor VIII showed positive associations with a variety of subclinical CVD measures. In age-adjusted analyses, fibrinogen and factor VIII were significantly associated with 8 of 10 measures. In multivariate analyses, fibrinogen was significantly associated with carotid artery stenosis, internal (but not common) carotid artery wall thickness, and AAI. Factor VIII was associated with abnormal wall motion and AAI in the full cohort only. Factor VII was not consistently associated with subclinical disease measures. In bivariate analyses that included data from all three groups, there were 5 positive subclinical disease associations and 5 negative associations for factor VII. In multivariate analyses, there were no significant associations between factor VII and subclinical CVD in the full cohort or in either subgroup. We conclude that in these cross-sectional analyses, fibrinogen and to a lesser extent factor VIII are associated with subclinical CVD in the elderly, even in those without symptoms or a history of clinical CVD. Factor VII, however, was not associated with subclinical CVD in the elderly.

Racial variation of factor VII activity and antigen levels and their correlates in healthy Chinese and Indians at low and high risk for coronary artery disease

Plasma factor VII activity (FVIIc) is one of the independent risk factors of coronary artery disease (CAD) and is controlled by both genetic and environmental factors. South Asians including Indians have one of the highest prevalence and mortality rates from CAD while the Chinese have a much lower risk. Generally accepted risk factors cannot explain the high mortality from CAD in Indians. We examined two hundred and seventy seven Chinese (124 m, 153 f); and 216 healthy Indian (150 m, 66 f) adults for serum lipids; plasma FVIIc and FVIIag levels in order to examine racial variations of these and their correlates in these two populations. Both Indian men and women had significantly higher FVIIc levels (12% and 11%, respectively) than the Chinese even after adjustments of age, BMI and lipids (P < 0.01). In contrast, Indians had significantly lower plasma FVIIag levels than Chinese (8% and 9%, respectively in men and women; P < 0.01). Multiple linear regression analysis shows a strong correlation of FVIIc with serum triglycerides accounting for 4-8% of the total variability of FVIIc in different groups. Further, there was a stronger correlation between FVIIc and FVIIag in Indians than that in the Chinese (0.43 vs. 25) suggesting a greater activation resulting in higher FVIIc in Indians inspite of lower FVIIag levels. The higher FVIIc and stronger activation by triglycerides observed in this study partly explain the higher risk of CAD in Indians.

Coagulation factor VII mass and activity in young men with myocardial infarction at a young age. Role of plasma lipoproteins and factor VII genotype

Factor VII (FVII) coagulant activity has been proven to be associated with the risk of future fatal coronary heart disease (CHD) in middle-aged men. Recent studies have emphasized the role of triglyceride-rich lipoproteins and FVII genotype in determining plasma levels of FVII protein and activity. The present study was undertaken to examine whether FVII activity state and protein concentration in fasting plasma are altered in young men with proven myocardial infarction (MI) and examined the relations of FVII to subfractions of apo B-containing lipoproteins and the Arg-->Gln polymorphism in the FVII gene. Activated FVII (FVIIa) was determined by a clotting assay using soluble, recombinant, truncated tissue factor. A total of 94 men with a first MI before the age of 45 (mean age +/- SD, 39.6 +/- 4.5 years) were included in the study along with 99 population-based, age-matched control subjects. In addition to FVIIa and FVII antigen (FVII:Ag), a panel of FVII activity assays were included for comparison with previous work in this field. The plasma level of FVII:Ag was higher in patients than in control subjects when the entire groups were compared (537 +/- 128 versus 479 +/- 93 ng/mL, P < .001), the differences being accounted for by patients with hypertriglyceridemic lipoprotein phenotypes. In contrast, FVIIa was similar in patients and control subjects (4.6 +/- 1.4 versus 4.3 +/- 1.3 ng/mL, NS), which means that the proportion of FVIIa molecules was unaltered or even lower in the patients. As expected, the Arg-->Gln polymorphism significantly influenced both FVII mass and activity levels. In addition, presence of the Gln allele appeared to be associated with a lower proportion of fully active FVII molecules. The polymorphism also affected the relation between the plasma concentration of VLDL and FVII:Ag. The triglyceride content and particle number of all VLDL subfractions, irrespective of particle size, correlated fairly strongly with FVII mass determinations but not at all with FVIIa. HDL cholesterol concentration, on the other hand, presumably reflecting the efficiency of lipoprotein lipase-mediated lipolysis of VLDL, related significantly to the FVIIa level. The Arg-->Gln polymorphism, independent of lipoprotein effects, explained 5% to 10% of the variation in FVII mass and activity. In conclusion, the present findings speak against a role of FVII as a risk factor for CHD, because a significantly increased potential for activation of coagulation (ie, raised basal concentration of FVIIa) was not observed among young postinfarction patients.(ABSTRACT TRUNCATED AT 400 WORDS)

The protein concentration of blood coagulation factor VII can be measured equally well in plasma and serum

In the Northwick Park Heart Study, the coagulant activity of factor VII (FVII:C) has been identified as a risk marker of ischaemic heart disease. In the fasting state, the protein concentration of FVII (FVII:Ag) might be an even better risk marker, because of the low coefficient of variation of the antigen assay. Today, most analyses are performed in plasma samples, as it is unknown whether FVII, to some extent, is consumed during coagulation. In the present study, we have investigated, whether FVII:Ag can be measured equally well in plasma and serum. FVII:Ag was measured in 88 plasma and serum samples. Results were compared by means of linear regression, where y = 0.984 x +0.770, r = 0.96. No systematic variation existed between FVII:Ag in plasma and serum. The mean difference in FVII:Ag between plasma and serum was -1.17 (SD 11.92) arbitrary units, compared with a mean difference of 0.18 (SD 8.31) arbitrary units between duplicate measurements of the same plasma dilution. Our findings indicate that there is a good agreement between FVII:Ag in plasma and serum.

Pathologic fibrin formation and cold-induced clotting of membrane oxygenators during cardiopulmonary bypass

In 1,800 patients undergoing cardiac surgery over a 2-year period, 11 incidents of abnormal inlet pressure elevations occurred before the membrane oxygenators. In 3 patients, the oxygenators had to be changed during cardiopulmonary bypass. This complication was found to be caused by fibrin formation possibly secondary to precipitation of fibrinogen with other coagulation factors in the heat exchangers of the oxygenators during the cooling phase. Large amounts of fibrin were demonstrated in the heat exchanger of the oxygenators. After careful washing of the apparatus, plasmin was added and fibrin was detected by measuring D-dimer levels. In heat exchangers from uneventful operations, only trace amounts of fibrin were found. Because there were no cold agglutinins demonstrated in the patients before surgery, cryoprecipitation studies were performed soon after surgery. When the patients' plasma samples were studied at different temperatures, from 37 degrees C down to 3 degrees C, cryoprecipitates or a gel (in 1 patient only) were formed. This indicated that there might be something abnormal with regard to fibrinogen-fibrin formation. The study patients were therefore investigated after the acute phase of the operation had ended for various coagulation factors, as well as for fibrin gel network characteristics. The results were compared with those of a control group (n = 10) with uneventful operations. There were no differences between the groups with regard to levels of coagulation factors VII and VIII and von Willebrand factor, although they were increased in both groups. The mean levels of coagulation inhibitors, antithrombin and Protein S, were slightly lower in the study patients. All of these patients had a highly pathologic, ie, tight fibrin gel network, except for the patient in whose sample a gel formed, despite being treated with aspirin or oral anticoagulants. The network was also tighter in some of the controls (v middle-aged reference individuals), although it was significantly tighter in the patients. It is concluded that some individuals who have an increased tendency to form tighter fibrin gel networks might be at increased risk for a severe complication during cardiac surgery performed under hypothermia.

Diabetic muscle infarction: a new perspective on pathogenesis and management

Two patients with insulin dependent diabetes mellitus developed recurrent episodes of focal muscle pain and swelling. Clinical evaluation, magnetic resonance imaging (MRI) and muscle biopsy confirmed the diagnosis of recurrent hemorrhagic muscle infarctions. Our studies suggest that muscle infarction occurred because of hypercoagulability and associated vascular endothelial damage. Based on these findings we recommend long-term anticoagulation to prevent recurrent infarction.

Association of factor VII genotype with plasma factor VII activity and antigen levels in healthy Indian adults and interaction with triglycerides

Plasma factor VII activity (factor VIIc) is one of the independent risk factors for coronary artery disease and is controlled by both genetic and environmental factors. Several studies in healthy Caucasian subjects have revealed an association of a common genetic polymorphism at residue 353 (Arg-->Gln) of the factor VII gene with plasma factor VIIc. We have investigated the influence of this polymorphism (factor VII Arg/Gln353) on fasting plasma factor VIIc and antigen (factor VIIag) levels and its interaction with triglyceride levels in 185 healthy Dravidian Indians of both sexes (128 men, 57 women). The frequency of Gln353 has been found to be significantly higher in Dravidian Indians (0.29; confidence interval, 0.27 to 0.30) than in Caucasians (0.10). The distribution of factor VII Arg/Gln353 genotypes was at Hardy-Weinberg equilibrium. The carriers of the Gln353 allele had significantly lower plasma factor VIIc and factor VIIag in men (P < .05). The factor VII Arg/Gln353 polymorphism explained 13% and 11% of the total variance of plasma factor VIIc and factor VIIag, respectively, in men (P < .001) and 6% and 9% in women (P > .1). The genotype-specific correlation of factor VIIc and factor VIIag with triglyceride levels was stronger in carriers of the Gln353 allele (r = .38 and .41; P < .001) than in Arg353 homozygotes (r = .09 and .27; P = .19 and .005, respectively).

Correlation of vitamin K-dependent clotting factors with cholesterol and triglycerides in healthy young adults

The plasma level of factor VII activity was a risk factor for the development of ischemic heart disease (IHD) in a prospective epidemiological study of hemostatic factors. We have previously reported significant correlations between factor VII clotting activity or antigen and lipid fractions in a group of 132 young men (< 30 years old) at low risk for IHD and concluded that control of the plasma factor VII level may be linked to lipid metabolism in normal male physiology. Because factor VII is one of four vitamin K-dependent procoagulant proteins, we hypothesized that plasma levels of all these proteins would be similarly controlled in normal physiology. In an extension of this study, we have measured two additional vitamin K-dependent clotting factors (prothrombin [factor II] and factor X activity), as well as factor VII activity and antigen and fasting serum lipid fractions in healthy young men and women (< 30 years old) at low risk for IHD. In the women, we found significant positive correlations of factor VII antigen with total or HDL cholesterol and of prothrombin or factor X with total or LDL cholesterol. In the men, factor VII activity or antigen correlated with total cholesterol, triglycerides, HDL cholesterol, or LDL cholesterol; prothrombin or factor X correlated with total cholesterol, triglycerides, or LDL cholesterol. In contrast, we found no significant correlations of fibrinogen with any of the lipid fractions in our groups of men or women. Our data support the hypothesis that control of the levels of the vitamin K-dependent procoagulant proteins is linked to lipid metabolism in the normal physiology of both men and women.

Fibrinolytic and thrombotic factors in atherosclerosis and IHD: the influence of triglyceride rich lipoproteins (TGRLP)

TGRLP interactions with the endothelium may increase the likelihood that a suppressed fibrinolytic capacity and/or an increased procoagulant activity enhances the risk for an ischemic event, that is, for the production of a focal thrombus. The cellular mechanisms and characteristics of TGRLP in hyperlipemia and in the postprandial state that contribute to their potential pathology in IHD are considered.

A chromogenic assay for coagulation factor VII: analytical performance characteristics and application in several diseases

A chromogenic assay for coagulation factor VII has been adapted for use on a Cobas Bio centrifugal analyzer. The interassay coefficients of variation ranged from 4.1% to 14%. There was no effect on the factor VII amidolytic activity after freezing and thawing of the samples. The test was linear up to 200% factor VII. The correlation with a chronometric method for prothrombin time was acceptable (r = 0.97, y = 1.05 x + 5.5). The reference ranges for males (54%-138%) and females (56%-200%) were significantly different. The factor VII amidolytic activities were significantly elevated in males with non-insulin-dependent diabetes mellitus and in male hypertensives. No statistically significant increase was observed for female patients rather a decrease in females with insulin-dependent diabetes mellitus. Only in the male hypertensive patients and in the male patients with non-insulin-dependent diabetes mellitus were noticeable proportions of increased values seen (39.4% and 12.0%). Nevertheless, the availability of a precise, rapid and easy to perform test for the determination of factor VII might be useful in the study of the role of this factor in the development of cardiovascular disease.

Plasma fibrinogen level is not elevated in young adults from families with premature ischemic heart disease

Several epidemiological studies have found that the plasma fibrinogen level is a risk factor for ischemic heart disease (IHD), similar in importance to the serum cholesterol level. A family history of IHD is also a significant risk factor for IHD, statistically independent of the serum cholesterol level. Whether the familial risk for IHD is related to genetic control of the fibrinogen level is unknown. Estimates of the genetic contribution to the variance in plasma fibrinogen levels vary markedly. We previously found elevated levels of cholesterol and factor VII in young subjects with a familial history of premature IHD. In the present study we chose to measure fibrinogen, factor VII antigen, and total cholesterol levels in 43 asymptomatic first-degree relatives (< 50 years old) of patients with premature IHD and in 43 age- and sex-matched asymptomatic young adults at low risk of IHD. No subjects in either group were smokers. The mean plasma fibrinogen level of the high-risk group (259 mg/dL) did not differ significantly from that of the low-risk group (250 mg/dL; p > 0.4). In contrast, the high-risk group had significantly higher mean factor VII antigen (p < 0.001) and mean serum cholesterol (p < 0.0001) than the low-risk group. These data argue against the hypothesis that genetic determination of the plasma fibrinogen level is a common pathophysiological mechanism responsible for familial risk of IHD.

Impact of weight loss on plasminogen activator inhibitor (PAI-1), factor VII, and other hemostatic factors in moderately overweight adults

Based on previous cross-sectional findings, we hypothesized that weight loss could improve several hemostatic factors associated with cardiovascular disease. In a randomized controlled trial, moderately overweight men and women were assigned to one of four weight loss treatment groups or to a control group. Measurements of plasminogen activator inhibitor-1 (PAI-1) antigen, tissue-type plasminogen activator (t-PA) antigen, D-dimer antigen, factor VII activity, fibrinogen, and protein C antigens were made at baseline and after 6 months in 90 men and 88 women. Net treatment weight loss was 9.4 kg in men and 7.4 kg in women. There was no net change (p > 0.05) in D-dimer, fibrinogen, or protein C with weight loss. Significant (p < 0.05) decreases were observed in the combined treatment groups compared with the control group for mean PAI-1 (31% decline), t-PA antigen (24% decline), and factor VII (11% decline). Decreases in these hemostatic variables were correlated with the amount of weight lost and the degree that plasma triglycerides declined; these correlations were stronger in men than women. These findings suggest that weight loss can improve abnormalities in hemostatic factors associated with obesity.