The hemostatic system and coronary heart disease

To study the dynamics of serum levels of vascular remodeling in patients with hypertension, including in combination with type 2 diabetes mellitus during 12‑month therapy with perindopril A

Aim      To study the dynamics of serum markers for vascular remodeling in patients with arterial hypertension (AH), including AH associated with type 2 diabetes mellitus (DM2) during the 12-month treatment with the angiotensin-converting enzyme (ACE) inhibitor, perindopril A.Material and methods  The study included patients with grade 1-2 AH with or without type 2 DM (30 and 32, respectively). Perindopril A 10 mg/day was administered for the outpatient correction of previous, ineffective antihypertensive therapy. The following biomarkers were measured for all patients at baseline and at 12 months: matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), E-selectin, endothelin 1, transforming growth factor β-1 (TGF-β1), and von Willebrand factor (WF). Laboratory tests were performed with enzyme immunoassay.Results After 12 months of the perindopril A (perindopril arginine) 10 mg/day treatment, both groups achieved the goal blood pressure. Evaluation of biomarker dynamics during the perindopril A treatment showed significant decreases in MMP-9, TIMP-1, and endothelin 1 in the AH group; then the level of TIMP-1 returned to normal values (р<0.05). In the AH+DM2 group, the MMP-9 concentration was significantly decreased (р<0.05); the other values did not show any significant differences. In both groups, MMP-9 was significantly decreased (28.6 % (р=0.01) in group 1 and 33.2 % (р=0.00) in group 2. Notably, in none of these groups, did this index reach normal values. Also, there were no significant differences in this index between the groups (р=0.66). It should be noted that the decreases in TIMP-1 were significantly different between the groups (р=0.001). Thus, this biomarker did not significantly decrease in patients with AH and DM2 (р=0.26) whereas in group 1 (AH without DM2), the level of TIMP-1 decreased by 39.3 % and reached the normal range (р=0.005).Conclusion      Concentrations of biomarkers were decreased in both groups. However, in the AH group, there were statistically significant decreases in the markers that reflect processes of fibrosis and vasoconstriction. At the same time in the AH+DM2 group, there was no significant dynamics of the biomarkers, which was most likely due to more pronounced damage of blood vessels. However, the decrease in MMP-9 may indicate an alleviation of fibrotic processes in arterial walls. These results allow a conclusion that the long-term treatment with the ACE inhibitor, perindopril A, may reverse remodeling of the vascular changes that are called "early vascular ageing".r aging".

Prognostic Value of Baseline d-Dimer Level in Patients With Coronary Artery Disease: A Meta-Analysis

The prognostic significance of d-dimer level in patients with coronary artery disease (CAD) is not fully established. This meta-analysis aimed to examine the association between elevated d-dimer level at baseline and adverse outcomes in patients with CAD. Two independent authors comprehensively searched PubMed and Embase databases from their inception to December 31, 2020. All observational studies reporting the values of baseline d-dimer level in predicting the major adverse cardiovascular events (MACEs) or survival outcomes in patients with CAD were included. The prognostic values were calculated by pooling adjusted RR with 95% CI for the highest versus the lowest d-dimer level. Thirteen studies consisting of 25 600 patients with CAD were identified. Comparison between the highest and lowest d-dimer level showed that the pooled multivariable adjusted RR was 1.69 (95% CI, 1.53-1.86) for all-cause mortality, 2.37 (95% CI, 1.52-3.69) for cardiovascular mortality, and 1.44 (95% CI, 1.19-1.74) for MACEs, respectively. Elevated blood level of d-dimer at baseline was independently associated with higher risk of MACEs, cardiovascular death, and all-cause mortality in patients with CAD. The baseline d-dimer level may have important prognostic value in patients with CAD.

Influence of autoimmunity and inflammation on endothelial function and thrombosis in systemic lupus erythematosus patients

The aim of this study is to assess the relationship between autoimmunity and endothelial activation/damage (ICAM-1 and vWF serum levels) and the degree of prothrombotic activity (thrombin-antithrombin complexes-TAT serum levels) in SLE. In 60 clinically stable SLE patients, levels of the following parameters were estimated in their serum: lupus anticoagulant (LA), anticardiolipin antibodies in both IgG and IgM classes (aCL-IgG and aCL-IgM, respectively), antiβ2GPI antibodies in both IgG and IgM classes (antiβ2GPI-IgG and antiβ2GPI-IgM, respectively), ICAM, von Willebrand factor (vWF), TAT, CRP, C3c, C4, and IL-6. ICAM-1 values exceeded the upper reference limit in 9 (15%) patients. vWF levels were increased in 21 (35%) patients. In all patients with elevated ICAM-1 values, vWF were also increased. TAT concentrations were elevated in 12 (20%) people. ICAM-1 were significantly higher in patients with elevated aCL-IgM (> 30 MPL vs ≤ 30 MPL; p < 0.05). Similarly, ICAM-1 were significantly higher in patients with elevated antiβ2-GPI-IgM (> 20 SMU vs ≤ 20 SMU; p < 0.05). There was no significant difference in ICAM-1 levels in relation to LA-positivity. vWF were not significantly different in relation to antiphospholipid antibodies nor the inflammation marker levels. TAT were significantly higher in patients with elevated aCL-IgM (> 30 MPL vs ≤ 30 MPL; p < 0.05). In one third of young patients with stable SLE, signs of endothelial activation/damage were found, as shown by elevated plasma ICAM-1 or vWF. Increased prothrombotic tendency manifested by elevated TAT was found in one fifth of the patients. Elevated anticardiolipin (IgM) and anti-β2-glycoprotein I (IgM) antibodies influence endothelial dysfunction and enhance prothrombotic state.

Differential effects of nonselective versus selective β-blockers on cardiac sympathetic activity and hemostasis in patients with heart failure

Carvedilol, a nonselective β-blocker, may be more effective than the selective β-blocker metoprolol in reducing the risk of thromboembolic events in heart failure. The aim of this study was, first, to assess whether there is a differential response in cardiac sympathetic activity by (123)I-meta-iodobenzylguanidine ((123)I-MIBG) imaging when either β-blocker is used. Second, we assessed whether that response correlates with levels of various serum factors that serve as markers for coagulability.

METHODS

In this prospective, randomized, open-label crossover study with masked outcome assessments, stable heart failure patients (left ventricular ejection fraction < 40%) homozygous for the Arg16/Gln27 (n = 13) or Gly16/Glu27 haplotype (n = 8) of the β2-receptor were randomized to equipotent dosages of carvedilol or metoprolol for two 6-wk periods. Primary outcome was sympathetic activity as measured by (123)I-MIBG myocardial washout. Secondary outcomes included markers of hemostasis.

RESULTS

(123)I-MIBG cardiac washout was lower during carvedilol than metoprolol treatment (12.9% ± 3.9% vs. 22.1% ± 2.8%, respectively, P = 0.003), irrespective of β2-adrenergic receptor haplotype. In addition, treatment with carvedilol resulted in a lower von Willebrand factor than did metoprolol (149% ± 13% vs. 157% ± 13%, respectively, P = 0.01), irrespective of β2-adrenergic receptor haplotype.

CONCLUSION

Compared with metoprolol, carvedilol resulted in greater reduction of sympathetic activity after 6 wk of treatment and lower von Willebrand factor concentrations in both Arg16/Gln27 and Gly16/Glu27 individuals. Therefore, carvedilol may reduce the risk of thromboembolic events in patients with heart failure, irrespective of β2-receptor haplotype status.

Polymorphisms in coagulation factors and the risk of recurrent cardiovascular events in men after a first myocardial infarction

BACKGROUND

The aim of this study was to examine whether genetic predisposition to high levels of coagulation factors influences the risk of developing fatal and non-fatal arterial cardiovascular events in men with a first myocardial infarction (MI).

METHODS

We performed a cohort study among 542 MI patients with a mean age of 56 years (range 32-70 years) at the time of the event. All of the men had a first MI between 1990 and 1996 and were followed until 1 September 2004. DNA was analyzed for polymorphisms of fibrinogen, prothrombin (factor II), factor V, factor VII and plasminogen activator inhibitor type 1, all of which are associated with gain of function of the protein. We collected information from hospital files and general practitioners on the occurrence of major arterial events.

RESULTS

In total, 254 major arterial cardiovascular events occurred during a median follow-up period of 11 years (range 0.2-15 years). The point estimates of the relative rates (RRs) of these events for the variant genotypes were all between 0.7 and 1.1 except for the prothrombin 20210A mutation: RR 1.8 (95% confidence interval 0.8-4.1).

CONCLUSION

These findings suggest that there is no association between coagulation factor polymorphisms, previously associated with plasma levels, and the risk of recurrent cardiovascular events.

Relationship between soluble thrombomodulin in patients with intermittent claudication and critical ischemia

INTRODUCTION

Thrombomodulin (TM) has been described as a marker of endothelial injury in atherosclerosis. The role of TM as a predictor of PAD severity is to be proven. The goal of the present study is to compare the level of plasmatic (TMp) in patients with intermittent claudication with patients with critical ischemia in the lower limbs.

MATERIALS AND METHODS

TMp was measured using ELISA in the plasma of 41 patients with intermittent claudication degree 1 and in 40 patients presenting critical ischemia in the lower limbs degrees 2 and 3, according to TASC. The hypotheses of normality and homogeneity of the variance had been proven via Shapiro-Wilk and Levene tests, respectively. The comparison of the TMp between the groups was done using the t-Student test.

RESULTS

No statistically significant difference was observed. The average levels of TMp for intermittent claudication were 5.2 ng/ml (0.78-13.61 ng/ml) and TMp for critical ischemia in the lower limbs were 6.34 (0.82-18.22 ng/ml) where p=0.265.

CONCLUSION

TMp does not seem to be an appropriate marker for PAD severity.

Genetics of atherosclerosis

Atherosclerosis, the primary cause of coronary artery disease (CAD) and stroke, is a disorder with multiple genetic and environmental contributions. Genetic-epidemiologic studies have identified a surprisingly long list of genetic and nongenetic risk factors for CAD. However, such studies indicate that family history is the most significant independent risk factor (15, 52, 77). Many Mendelian disorders associated with atherosclerosis, such as familial hypercholesterolemia (FH), have been characterized, but they explain only a small percentage of disease susceptibility (although a substantial fraction of early CAD). Most cases of myocardial infarction (MI) and stroke result from the interactions of multiple genetic and environmental factors, none of which can cause disease by itself. Successful discovery of these genetic factors will require using complementary approaches with animal models, large-scale human genetic studies, and functional experiments. This review emphasizes the common, complex forms of CAD.

Exercise and Training Effects on Blood Haemostasis in Health and Disease

In recent years, the dysfunction of the haemostatic system in relation to the clinical complications from arterioscleroses and cardiovascular diseases has become more recognised. Blood coagulation and fibrinolysis comprise two important physiological systems, which are regulated by a balance between activators and inhibitors. Activation of blood coagulation is associated with accelerated clot formation, whereas activation of blood fibrinolysis enhances the breakdown of the blood clot. Available evidence suggests that strenuous exercise induces activation of blood coagulation with simultaneous enhancement of blood fibrinolysis. Although the responses of blood coagulation and fibrinolysis appear to be related to the exercise intensity and its duration, recent reports suggest that moderate exercise intensity is followed by activation of blood fibrinolysis without concomitant hyper-coagulability, while very intense exercise is associated with concurrent activation of blood coagulation and fibrinolysis. Similar to blood coagulation and fibrinolysis, systemic platelet-related thrombogenic factors have been shown to be involved in the initiation and progression of atherogenesis and plaque growth. Although exercise effects on platelet aggregation and function in healthy individuals have been examined, the results reported have been conflicting. However, for patients with coronary heart disease, the balance of evidence available would strongly suggest that platelet aggregation and functions are increased with exercise. Few studies are available concerning the influence of training on blood coagulation and fibrinolysis and the exact effects of exercise training on the equilibrium between blood coagulation and fibrinolysis is not as yet known. Although the effects of physical training on platelets have been briefly investigated, available meagre evidence suggests that exercise training is associated with favourable effects on platelet aggregation and activation in both men and women.

Effects of ageing and regular aerobic exercise on endothelial fibrinolytic capacity in humans

The capacity of the vascular endothelium locally to release tissue-type plasminogen activator (t-PA) is critical for effective endogenous fibrinolysis. We determined the influence of ageing and regular aerobic exercise on the net release of t-PA across the human forearm in vivo using both cross-sectional and intervention approaches. First, we studied 62 healthy men aged 22-35 or 50-75 years of age who were either sedentary or endurance exercise-trained. Net endothelial release rates of t-PA were calculated as the product of the arteriovenous concentration gradient and forearm plasma flow to intra-arterial bradykinin and sodium nitroprusside. Second, we studied 10 older (60 +/- 2 years) healthy sedentary men before and after a 3 month aerobic exercise intervention. Net endothelial t-PA release was significantly blunted with age in the sedentary men. At the highest dose of bradykinin the increase in t-PA antigen release was approximately 35 % less (P < 0.05) in the older (from -1.0 +/- 0.4 to 37.8 +/- 3.8 ng (100 ml tissue)(-1) min(-1)) compared with young (from 0.1 +/- 0.6 to 56.6 +/- 9.2 ng (100 ml tissue)(-1) min(-1)) men. In contrast, the endurance-trained men did not demonstrate an age-related decline in the net release of t-PA antigen. After the exercise intervention, the capacity of the endothelium to release t-PA increased approximately 55 % (P < 0.05) to levels similar to those of the young adults and older endurance-trained men. Regulated endothelial t-PA release declines with age in sedentary men. Regular aerobic exercise may not only prevent, but could also reverse the age-related loss in endothelial fibrinolytic function.

n-3 polyunsaturated fatty acids and coronary thrombosis

Studies of Greenland Eskimos showed that a very high intake of marine n-3 fatty acids markedly inhibited platelet reactivity and suggested that intake of these fatty acids might prevent coronary thrombosis. Later studies with lower, more practical doses of n-3 fatty acids also have shown a platelet inhibitory effect of n-3 fatty acids, albeit fairly marginal. Furthermore, n-3 fatty acids have little effect on measures of blood coagulability and may slightly decrease fibrinolysis. In animal models, n-3 fatty acids often have been shown to inhibit thrombosis, but again the doses have tended to be very high. Finally, there has been little effect of (low-dose) n-3 fatty acids in clinical trials in humans on the incidence of myocardial infarction. Overall, there is little evidence for a major antithrombotic effect of practical doses of n-3 fatty acids on coronary thrombosis. This does not exclude a beneficial effect of n-3 fatty acids on coronary heart disease as suggested from clinical trials, but the major effect may be antiarrhythmic rather than antithrombotic.

Effects of atorvastatin on postprandial plasma lipoproteins in postinfarction patients with combined hyperlipidaemia

Enhanced and prolonged postprandial lipaemia is implicated in coronary and carotid artery disease. This study assessed the effects of atorvastatin, a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, on postprandial plasma concentrations of triglyceride-rich lipoproteins (TRLs). Sixteen middle-aged men with combined hyperlipidaemia (baseline low density lipoprotein (LDL) cholesterol and plasma triglyceride concentrations (median (interquartile range) of 4.54 (4.17-5.26)) and 2.66 (2.04-3.20) mmol/l, respectively) and previous myocardial infarction were randomised to atorvastatin 40 mg or placebo once daily for 8 weeks in a double-blind, cross-over design. The apolipoprotein (apo) B-48 and B-100 contents were determined in subfractions of TRLs as a measure of chylomicron remnant and very low density lipoprotein (VLDL) particle concentrations (expressed as mg apo B-48 or apo B-100 per litre of plasma), in the fasting state and after intake of a mixed meal. Atorvastatin treatment reduced significantly the fasting plasma concentrations of VLDL cholesterol, LDL cholesterol and VLDL triglycerides (median% change) by 29, 44 and 27%, respectively, and increased high density lipoprotein (HDL) cholesterol by 19%, compared with baseline. The postprandial plasma concentrations of large (Svedberg flotation rate (Sf) 60-400) and small (Sf 20-60) VLDLs and chylomicron remnants were almost halved compared with baseline (mean 0-6 h plasma concentrations were reduced by 48% for Sf 60-400 apo B-100, by 46% for Sf 60-400 apo B-48, by 46% for Sf 20-60 apo B-100 and by 27% for Sf 20-60 apo B-48), and the postprandial triglyceridaemia was reduced by 23% during active treatment. In conclusion, atorvastatin 40 mg once daily causes profound reductions of postprandial plasma concentrations of all TRLs in combined hyperlipidaemic patients with premature coronary artery disease.

Retained fibrinolytic response and no coagulation activation after acute physical exercise in middle-aged women with previous myocardial infarction

Sudden physical exertion is associated with an increased risk of acute myocardial infarction (MI) and sudden cardiac death. In addition, activation of the coagulation cascade and/or reduced fibrinolytic capacity after physical exercise has been reported in patients with cardiovascular disease. We investigated the haemostatic responses to an acute submaximal physical exercise in middle-aged women with a history of MI compared with healthy, age-matched controls. Resting plasma von Willebrand factor antigen (vWF Ag) and tissue plasminogen activator (tPA) antigen concentrations and plasminogen activator inhibitor-1 (PAI-1) activity were higher in the patients compared with control subjects. After 30 min of submaximal exercise on a bicycle ergometer, small, but still significant, increases in fibrinogen and vWF Ag concentrations were found in both groups. However, exercise did not induce thrombin generation and fibrin formation, as assessed by thrombin-antithrombin complex and fibrin D-dimer, in either group. Both tPA antigen concentration and activity increased and PAI-1 activity decreased significantly with exercise in both groups. Interestingly, the magnitude of changes in these latter variables did not differ between the groups (P=.99, P=.88 and P=.24, respectively). The present study demonstrates that some middle-aged women with previous MI have no signs of coagulation activation and retained fibrinolytic response after submaximal exercise. The clinical implication of these results might be that women with stable coronary heart disease can participate in rehabilitative exercise training without exhibiting a procoagulative state.

Trends in coronary risk factors in the WHO MONICA project

BACKGROUND

The World Health Organization (WHO) MONICA Project was established to determine how trends in event rates for coronary heart disease (CHD) and, optionally, stroke were related to trends in classic coronary risk factors. Risk factors were therefore monitored over ten years across 38 populations from 21 countries in four continents (overall period covered: 1979-1996).

METHODS

A standard protocol was applied across participating centres, in at least two, and usually three, independent surveys conducted on random samples of the study populations, well separated within the 10-year study period.

RESULTS

Smoking rates decreased in most male populations (35-64 years) but in females the majority showed increases. Systolic blood pressure showed decreasing trends in the majority of centres in both sexes. Mean levels of cholesterol generally showed downward trends, which, although the changes were small, had large effects on risk. There was a trend of increasing body mass index (BMI) with half the female populations and two-thirds of the male populations showing a significant increase.

CONCLUSIONS

It is feasible to monitor the classic CHD risk factors in diverse populations through repeated surveys over a decade. In general, the risk factor trends are downwards in most populations but in particular, an increase in smoking in women in many populations and increasing BMI, especially in men, are worrying findings with significant public health implications.

Effects of acute exercise on hemorheological, endothelial, and platelet markers in patients with chronic heart failure in sinus rhythm

BACKGROUND

Chronic heart failure (CHF) is associated with an increased risk of thrombosis and thromboembolic events, including stroke and venous thromboembolism. which may be related to a prothrombotic or hypercoagulable state. Acute vigorous exercise has been associated with activation of hemostasis, and this risk may well be particularly increased in patients with CHF.

HYPOTHESIS

The study was undertaken to determine whether acute exercise would adversely affect abnormalities of hemorheological (fibrinogen, plasma viscosity, hematocrit), endothelial (von Willebrand factor), and platelet markers (soluble P selectin) in patients with CHF.

METHODS

We studied 22 ambulant outpatients (17 men; mean age 65+/-9 years) with stable CHF (New York Heart Association class II-III and a left ventricular ejection fraction of < or =40%) who were exercised to exhaustion on a treadmill. Results were compared with 20 hospital controls (patients with vascular disease, but free of CHF) and 20 healthy controls.

RESULTS

Baseline von Willebrand factor (p = 0.01) and soluble P-selectin (p = 0.006) levels were significantly elevated in patients with CHF when compared with controls. In the patients with CHF who were exercised, plasma viscosity, fibrinogen, and hematocrit levels increased significantly, both immediately post exercise and at 20 min into the recovery period (repeated measures analysis of variance, all p<0.05). There was a positive correlation between exercise workload and the maximal changes in plasma viscosity in the patients with CHF (Spearman r = 0.5, p = 0.02). Plasma viscosity levels increased with exercise in the hospital control group, although no other exercise-induced changes were noted in this group.

CONCLUSION

The present study indicates that the hemorheological indices. fibrinogen, and hematocrit specifically increase during acute exercise in patients with CHF. Although moderate exercise should be encouraged in patients with CHF, vigorous exercise should probably be avoided in view of its potential prothrombotic effects in this high-risk group of patients.

Impaired fibrinolysis determines the outcome of percutaneus transluminal coronary angioplasty (PTCA)

BACKGROUND

Coronary artery stenosis lesions dilated by percutaneus transluminal coronary angioplasty (PTCA) show a disappointingly frequent recurrence of stenosis. We have investigated the possible role of fibrinolysis and various platelet-release factors - specifically in the locality of the affected vessel - by following 19 patients for 6 months after PTCA.

METHODS

PTCA was performed on 19 patients with a significant primary coronary stenosis, proven by quantitative CAAS analysis. Blood for measurement of local fibrinolysis and platelet activity was drawn from the aortic root and the coronary sinus, at three times: just before PTCA, 10 min after it, and 6 months later.

RESULTS

The incidence of restenosis at the 6 months follow-up was 37%. PTCA almost doubled the platelet-derived growth factor level (PDGF) in coronary sinus blood in all patients. The seven restenosis patients had a substantially higher tissue plasminogen activator inhibitor antigen (PAI-1ag) level in the aortic root before PTCA than the 12 who remained stenosis-free (mean 62.4 +/- 31.6 ng mL -1 compared with 33.1 + 25.3; P < 0.04) and a lower tissue plasminogen activator activity (t-PAac) level (mean 0.32 +/- 0.19 IU mL-1 compared with 0.68 +/- 0.34; P < 0.03). This was corroborated by the levels of tissue plasminogen activator inhibitor activity (PAI-1ac). At reassessment after 6 months, the restenosis patients had developed, in coronary sinus blood, a large rise of PAI-1ac (7.7 +/- 4.8 IU mL-1 rising to 15.7 +/- 13.9, P < 0.04) and a large rise of of PAI-1ag (48.8 +/- 31.3 ng mL-1 vs. 72.4 +/- 47.2; P < 0.03). But no such increase occurred in the patients who remained stenosis-free. Conclusion Our results indicate that the minor balloon injury, which is inseparable from PCTA, stimulates the local release of PDGF. We suggest that, in those patients whose fibrinolytic activity is inherently low, this rise of PDGF could be a major causative factor in restenosis. We also discuss the possibility that the preoperative level of PAI-1ac could provide a limited but useful prediction of the outcome of PTCA.

Racial and genetic determinants of plasma factor XIII activity

Factor XIII (F XIII), a plasma transglutaminase, is essential for normal hemostasis and fibrinolysis. Plasma F XIII consists of two catalytic A (F XIIIA) and two non-catalytic B (F XIIIB) subunits. Activated F XIII is involved in the formation of fibrin gel by covalently crosslinking fibrin monomers. As the characteristics of the fibrin gel structure have been shown to be associated with the risk of coronary heart disease (CHD), F XIII activity may play a seminal role in its etiology. In this investigation, we determined plasma F XIII activity in two racial groups, including Asian Indians (n = 258) and Chinese (n = 385). Adjusted plasma F XIII activity was significantly higher in Indian men (142 vs. 110%; P<0.0001) and women (158 vs. 111%; P<0.0001) than their Chinese counterparts. As compared to Indians where the distribution of F XIII activity was almost normal, in Chinese it was skewed towards low activity. In both racial groups, bivariate and multivariate analyses showed strong correlation of F XIII activity with plasma fibrinogen and plasminogen levels. Race explained about 25% of the variation in F XIII activity even after the adjustment of significant correlates. We also determined the contribution of common genetic polymorphisms in the F XIIIA and F XIIIB genes in affecting plasma F XIII activity. Both loci showed significant and independent effects on plasma F XIII activity in Indians (F XIIIA, P< 0.01; F XIIIB, P<0.05) and Chinese (F XIIIA, P<0.0001; F XIIIB, P<0.13) in a gene dosage fashion. This study shows that both racial and genetic components play a significant role in determining plasma F XIII activity, and consequently it may affect the quantitative risk of CHD.

Surgical stress induces acute coronary release of tissue-type plasminogen activator in the pig

BACKGROUND

Tissue-type plasminogen activator (t-PA) is an endothelium derived key enzyme in the initiation of endogenous fibrinolysis. Acute regulated release of active t-PA occurs within minutes in response to threatening thrombotic vessel occlusion. The aim of this study was to investigate the impact of surgical stimulation on the kinetics of t-PA release in the coronary vascular bed in the pig.

METHODS

In anaesthetised pigs (n=16), arterio-venous concentration gradients of t-PA, and plasma flows (retrograde thermodilution) were obtained across the coronary vascular bed before (control) and at 1, 3, 5 and 10 min after sternotomy.

RESULTS

At control, no significant coronary net flux (release or uptake) of t-PA was observed, while sternotomy induced a rapid net release of total t-PA (132.6 ng x min(-1)), with an associated increase in active t-PA (93.6 ng x min(-1)). This response, evident already after 1 min, showed a peak at 5 min and returned towards baseline levels within 10 min. No concurrent alterations in aortic levels of active t-PA were found and haemodynamic variables were unaltered.

CONCLUSION

The rapidly increasing and transient net coronary release of t-PA after sternotomy suggests that the endothelium actively promotes local endogenous fibrinolysis during surgery. Such events could reflect a dynamic responsiveness to protect the coronary circulation during stress.

Pulmonary function, smoking cessation and 30 year mortality in middle aged Finnish men

BACKGROUND

Although it is well known that impaired pulmonary function is a strong predictor of mortality and that smoking decreases pulmonary function, little is known about the long term effect of smoking cessation on mortality at different levels of pulmonary function. We have studied the impact of smoking cessation on mortality over the entire range of baseline pulmonary function.

METHODS

The study subjects consisted of men aged 40-59 at entry who were the Finnish participants in the Seven Countries Study during 1959-89.

RESULTS

In all the participants (n = 1582) impaired forced expiratory volume in 0.75 seconds (FEV(0.75)) was significantly associated with increased all cause mortality. When those who gave up smoking during the follow up period were compared with continuous smokers (n = 860) all cause mortality was found to be decreased among those who quit. The relative adjusted hazard (HR) was 0.71 (95% confidence interval 0.50 to 1.00). The median survival time in those who stopped smoking compared with those who continued to smoke from 1969 onwards was 7.65, 7.59, and 6.30 years longer in the lowest, middle and highest tertiles of adjusted FEV(0.75) distribution, respectively. In those who gave up smoking, mortality from cardiovascular causes was significantly lower (HR 0.60 (95% CI 0.37 to 0.98)).

CONCLUSIONS

These findings suggest that smokers across the entire range of pulmonary function may increase their expectation of lifespan by giving up smoking.

Blood hemostasis in exercise and training

Formation of the blood clot is a slow but normal physiological process occurring as a result of the activation of blood coagulation pathways. Nature's guard against unwanted blood clots is the fibrinolytic enzyme system. In healthy people, there is a delicate dynamic balance between blood clot formation and blood clot dissolution. Available evidence suggests that exercise and physical training evoke multiple effects on blood hemostasis in normal healthy subjects and in patients. A single bout of exercise is usually associated with a transient increase in blood coagulation as evidenced by a shortening of activated partial thromboplastin time (APTT) and increased Factor VIII (FVIII). The rise in FVIII is intensity dependent and continues into recovery. The effects of acute exercise on plasma fibrinogen have yielded conflicting results. Thus, the issue of whether exercise-induced blood hypercoagulability in vitro mirrors an in vivo thrombin generation and fibrin formation remains disputable. Exercise-induced enhancement of fibrinolysis has been repeatedly demonstrated using a wide range of exercise protocols incorporating various exercise intensities and durations. Moderate exercise appears to enhance blood fibrinolytic activity without a concomitant activation of blood coagulation mechanisms, whereas, very heavy exercise induces simultaneous activation of blood fibrinolysis and coagulation. The increase in fibrinolysis is due to a rise in tissue-type plasminogen activator (tPA) and decrease in plasminogen activator inhibitor (PAI). The mechanism of exercise-induced hyperfibrinolysis is poorly understood, and the physiological utility of such activation remains unresolved. Strenuous exercise elicits a transient increase in platelet count, but there are conflicting results concerning the effect of exercise on platelet aggregation and activation. Few comprehensive studies exist concerning the influence of exercise training on blood hemostasis, making future investigation necessary to identify whether there are favorable effects of exercise training on blood coagulation, fibrinolysis, and platelet functions.

Hypercoagulable states

The hypercoagulable state has been defined as the potential to develop thrombosis in association with hereditary and noninherited genetic mutations and acquired disorders. It is a condition that places an individual at risk for, but does not in itself inevitably lead to, thrombosis. The focus of this article is understanding mechanisms in the hypercoagulable state that enhance and maintain the production of thrombin in circulating blood while preventing its progression to thrombosis. These mechanisms include reactions that produce thrombin from prothrombin, feedback loop mechanisms that affect the rate of thrombin production from prothrombin and the inactivation of thrombin in blood. The fibrinolytic system is involved in clot lysis but not in thrombin production and inactivation.

Differential regulation by troglitazone of plasminogen activator inhibitor type 1 in human hepatic and vascular cells

Troglitazone, a novel oral insulin sensitizer, normalizes increased plasma activity of plasminogen activator inhibitor type 1 (PAI-1) in hyperinsulinemic patients such as women with polycystic ovary syndrome and patients with type 2 diabetes mellitus. However, underlying mechanisms have not yet been fully elucidated. Human hepatic and vascular cells, the main sources of circulating PAI-1, were studied in cell culture. In human hepatic cells, PAI-1 accumulated in conditioned medium by 23% within 24 h after exposure to 3 microg/mL troglitazone (P = 0.001). The accumulation depended on the concentration of troglitazone, but not that of insulin (known to stimulate PAI-1 synthesis). By contrast, in human aortic smooth muscle cells, 3 microg/mL troglitazone decreased basal PAI-1 expression by 23% (P = 0.037) and decreased transforming growth factor-beta-induced expression by 34% (P = 0.026). Concomitant insulin had no effect. Tissue-type plasminogen activator was decreased by 38% (P = 0.002). In human endothelial cells, PAI-1 was diminished by 32% (P < 0.001), whereas tissue-type plasminogen activator was unaffected. The results suggest that the reduction in plasma activity of PAI-1 induced by troglitazone in patients may reflect both directly mediated diminution of its elaboration from vessel walls and indirectly mediated reduction of its hepatic synthesis secondary to attenuation of hyperinsulinemia (known to increase the hepatic synthesis of PAI-1).

Thrombophilia in Patients with Hypertriglyceridemia

Objectives: To investigate a possible relationship between hypertriglyceridemia and the coagulation system, a Cardiovascular Risk Factor Two-township Study was conducted in Taiwan. Design: A case-control study. This longitudinal, prospective study focused on the evolution of cardiovascular disease risk factors with emphasis on haemostatic factors. Subjects: Hypertriglyceridemic subjects (triglyceride <2.26 mmoll+1, n = 327) and age-matched normal controls from a population screening program. Main outcome measures: Haemostatic parameters measured in this study included prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, factors VIIc and VIIIc, and antithrombin-III and plasminogen levels. Results: In our male hypertriglyceridemic subjects, aPTT was not significantly reduced, while significant elevations of factor VIIIc, factor VIIc, and plasminogen and antithrombin-III levels were noted. In the female hypertriglyceridemic subjects, the elevation of factor VIIc, factor VIIIc, and plasminogen and antithrombin-III levels was highly-significant, whereas aPTT was not significantly reduced. Unexpectedly, the levels of the established coronary risk factor, fibrinogen, did not show a statistically different change. Similar to previous data, our hypertriglyceridemic subjects also presented with hyperinsulinemia, glucose intolerance, upper body obesity, and elevated blood pressure. Conclusions: Despite the fact that in population studies, triglycerides do not consistently appear to be an independent risk factor for coronary heart disease, our data suggest that a pronounced increase in triglycerides warrants aggressive therapy, because this increase may be associated with a hypercoagulable state. This phenomenon contributes another perspective to the study of higher cardiovascular mortality in hypertriglyceridemic subjects.

Effect of micronized fenofibrate on plasma lipoprotein levels and hemostatic parameters of hypertriglyceridemic patients with low levels of high-density lipoprotein cholesterol in the fed and fasted state

A randomized, double-blind, placebo-controlled study was undertaken in 20 hypertriglyceridemic men [plasma triglyceride (TG), >2.3 mM] with low levels (<0.9 mM) of high-density lipoprotein cholesterol (HDL-C) to investigate the ability of micronized fenofibrate (Tricor or Lipidil; 200 mg/day) to affect atherogenic and thrombogenic plasma risk factors in the fed and fasted state. Each patient underwent (a) 4 weeks of dietary stabilization, (b) 8 weeks of treatment with fenofibrate or placebo, (c) a 5-week washout period, and (d) 8-weeks of treatment with the alternative medication. An oral fat-loading test (1 g fat/kg body weight) was carried out after both treatment periods. Before treatment, patients had a mean (+/- SD) total plasma TG of 3.31+/-0.93 mM; total C, 5.75+/-0.89 mM; HDL-C, 0.71+/-0.09 mM; and low-density lipoprotein (LDL)-C, 3.40+/-0.68 mM. Compared with placebo, fenofibrate reduced fasting TG levels by 36%, and triglyceride-rich lipoprotein (TRL, d<1.006 g/ml) -TG, and TRL-C levels by approximately 40%. In the postprandial state, fenofibrate reduced total TG, TRL-TG, TRL-C, TRL-apoC-III, and TRL-apoE levels by -35% (all values of p<0.01). Fasted and fed HDL-C and apoA-I levels were increased -10%, and total cholesterol/HDL cholesterol ratios were decreased -15% by fenofibrate. No significant differences were observed in mean LDL-C and LDL-apoB levels. A 6% increase in the LDL-C/LDL-apoB ratio during fenofibrate treatment indicated a shift to larger, more buoyant LDL particles. A small, but statistically significant (p<0.01) increase was observed in fasted and fed Lp(a) levels during fenofibrate treatment. Hemostatic parameters were not significantly affected by fenofibrate, except for a 12-15% decrease (p<0.05) in fibrinogen levels in the fasted and fed state, and a significant increase (43%; p<0.05) in fasting levels of plasminogen activator-inhibitor-1. These data demonstrate that micronized fenofibrate is highly effective, in both the fed and fasted state, in reducing TRL lipids and apolipoproteins, and in reducing plasma fibrinogen levels of men with an atherogenic lipoprotein profile.

Tissue plasminogen activator, plasminogen activator inhibitor-1, and tissue plasminogen activator/plasminogen activator inhibitor-1 complex as risk factors for the development of a first stroke

BACKGROUND NAD PURPOSE: Abnormalities in the fibrinolytic system have been associated with an increased risk for stroke in a few studies. This study was designed to test whether plasma levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), and tPA/PAI-1 complex could predict a first-ever stroke.

METHODS

The study was an incident case-control study nested within the Västerbotten Intervention Program and the Northern Sweden Monitoring Trends and Determinants in Cardiovascular Disease (MONICA) cohorts. In this study 108 first-ever stroke cases were defined according to the MONICA classification, and 216 controls from the same cohort were randomly selected and matched for age, sex, sampling time, and geographic region.

RESULTS

Stroke occurred on average 30 months after the blood sampling date. The mean plasma concentration of tPA/PAI-1 complex was higher for the stroke cases than for the controls (3.9 versus 3.0 microgram/L). In univariate regression analysis, significantly higher odds ratios were found for the tPA/PAI-1 complex as continuous variable. When divided into quartiles, the odds ratio was 2.74 for the highest quartile compared with the lowest. In the multivariate model, the tPA/PAI-1 complex remained an independent predictor for stroke. Additionally, tPA mass concentration quartiles 3 and 4 showed a significant association with all stroke as outcome. No association was found, however, for PAI-1. In subgroup analysis of cerebral hemorrhage (n=18), the mean tPA/PAI-1 complex level was higher for the cases than for the controls (4.8 versus 3.0 microgram/L), and in multivariate analysis including all controls (n=216), only tPA/PAI-1 complex remained significant.

CONCLUSIONS

This prospective study shows that tPA/PAI-1 complex, a novel fibrinolytic marker, is independently associated with the development of a first-ever stroke, especially hemorrhagic stroke. This finding supports the hypothesis that disturbances in fibrinolysis precede a cerebrovascular event.

Exercise induces a change in plasma fibrinogen concentration: fact or fiction?

This study examined the effect of exercise on plasma fibrinogen concentrations with simultaneous measurements of plasma volume changes. Eight moderately active males aged 26.6+/-3.6 years (mean +/- SD) completed maximal (VO2max) and submaximal (75% VO2max for 30 minutes) exercise trials separated by 7 days. Venous blood samples were obtained at rest, immediately postexercise, and following 30 minutes of recovery. Whole blood was analysed for haematocrit and haemoglobin, while citrated plasma was assayed for fibrinogen levels. Values of haematocrit and haemoglobin before and after exercise were utilised for the estimation of plasma volume changes. Plasma volume decreased (p<0.05) immediately following both maximal (-17.7+/-5.1%) and submaximal (-14.3+/-4.1%) exercise. Exercise resulted in decreased plasma fibrinogen levels (maximal exercise: from 266.3+/-14.5 to 222.2+/-23.9 mg x dL(-1); submaximal exercise: from 239.5+/-45.4 to 209.7+/-42.4 mg x dL(-1)) only when postexercise raw data were corrected for the contraction of plasma volume. It is concluded therefore that changes in plasma volume in response to exercise should be taken into account when interpreting exercise effects on plasma fibrinogen concentration.

Work stress and metabolic and hemostatic risk factors

OBJECTIVE

A high level of work stress has been associated with cardiovascular disease. However, the pathophysiological mechanisms underlying this association remain unclear. This study examined the effect of work stress on a cluster of metabolic and hemostatic risk factors.

METHODS

Blood was collected three times, on the first, third, and fifth day of a work week, from 124 middle-aged, white-collar workers. Metabolic measures were insulin, glucose, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and total cholesterol. Hemostatic measures were fibrinogen, tissue-type plasminogen activator activity, tissue-type plasminogen activator antigen, and type 1 plasminogen activator inhibitor antigen. Chronic work stress was defined according to Siegrist's model as 1) a combination of high effort and low reward at work (effort-reward imbalance) or 2) high overcommitment (an exhaustive work-related coping style).

RESULTS

Overcommitment, but not imbalance or the imbalance-overcommitment interaction, was associated with an impaired fibrinolytic system, as reflected in decreased tissue-type plasminogen activator activity levels and increased type 1 plasminogen activator inhibitor antigen levels on all three measurement occasions. After controlling for body mass index, total cholesterol, triglycerides, high-density lipoprotein/low-density lipoprotein cholesterol ratio, glucose, and insulin, the relation between overcom-mitment and the fibrinolytic factors was attenuated but remained significant.

CONCLUSIONS

The results suggest that individuals with an exhaustive coping style at work have an impaired fibrinolytic capacity that is possibly due to the effects of chronic stress on insulin resistance.

Haemodynamic responses and changes of haemostatic risk factors in cold-adapted humans

Epidemiological studies have shown an increase in acute myocardial infarctions or deaths due to myocardial infarction in colder weather; the mechanisms most likely involve increased blood levels of haemostatic risk factors, and increases in arterial blood pressure and heart rate. We studied the relationship between cold adaptation, haemostatic risk factors and haemodynamic variables. Cold adaptation was obtained by a programme of immersion of the whole body up to the neck in a water-filled bath, the temperature of which was gradually decreased from 22 degrees C to 14 degrees C, time of exposure being increased from 5 to 20 min over a period of 90 days. We studied 428 patients (44% men) and measured blood levels of fibrinogen, plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator antigen (t-PA), plasma viscosity, von Willebrand factor, D-dimer and platelet count, both at baseline and after 90 days of daily immersion. There were significant reductions in von Willebrand factor (-3%; p < 0.001), and plasma viscosity (-3.0 s; p < 0.001), and a mild but significant increase in PAI-1 (+0.3 IU/ml; p = 0.02). The pressure rate product (systolic blood pressure x heart rate) was also significantly lower after cold adaptation (-310; p = 0.004). Cold adaptation, compared with exposure to cold weather, induces different haemodynamic responses and changes of blood levels of haemostatic risk factors.

The influence of a vegetarian diet on haemostatic risk factors for cardiovascular disease in Africans

Dietary habits have been implicated in the occurrence of cardiovascular diseases. Elevated plasma fibrinogen levels and decreased fibrinolytic activity have been identified as major independent cardiovascular risk factors. In this study, we compared the blood pressure, plasma fibrinogen concentration, and fibrinolytic activity of 40 nonvegetarians (NON-VEGs) with 36 vegetarians (8 VEGs and 28 SEMI-VEGs). The latter group consisted of students and lecturers of the Adventist Seminary Institute of West Africa, Ilishan Remo. All subjects had blood pressures below 140/90 mmHg, no underlying haemostatic disorders and were not on any medical treatment. The NON-VEGs had significantly decreased fibrinolytic activity (p<0.001) and increased plasma fibrinogen levels (p<0.001) compared with the SEMI-VEGs and VEGs. There were no significant differences between the blood pressure levels of the three groups, although the NON-VEGs had lower diastolic blood pressures. It is concluded that black African Seventh-Day Adventists who follow a vegetarian diet may be protected against premature cardiovascular disease because of beneficial dietary effects on plasma fibrinogen levels and fibrinolytic activity.

Symptoms of chronic bronchitis, haemostatic factors, and coronary heart disease risk

Positive association has been suggested between a variety of infections and coronary heart disease. Disturbances in blood coagulation system may form a link between infections and coronary heart disease. The aim of this study was to analyze whether chronic bronchitis, defined by the occurrence of symptoms, is associated with selected haemostatic factors in a cross-sectional population study of 2379 Finnish men and women aged between 45 and 64 years. Plasma fibrinogen level was significantly higher, 3.70 versus 3.35 g/l (P < 0.001) in men and 3.64 versus 3.44 g/l (P < 0.001) in women, among subjects with symptoms of chronic bronchitis than among those without symptoms. The association was independent of age, smoking, body mass index, physical exercise, and alcohol consumption. Also plasminogen was higher among men with symptoms than among those without but the difference disappeared after adjustment for age and smoking. Factor VII coagulant activity and factor VII antigen level did not differ between subjects with and without symptoms. Thus, fibrinogen may be associated with a possible mechanism to link chronic bronchitis to coronary heart disease risk, even though the causality of the association cannot be verified in a cross-sectional study.

Measurement of prethrombotic markers in the assessment of acquired hypercoagulable states

Hypercoagulable states can be detected by measuring activation peptides, enzyme-inhibitor complexes, and fibrin/fibrinogen degradation products, which are markers of hemostatic activation. A series of these prethrombotic markers has been evaluated in the elderly, pregnancy, diabetes and acute myocardial infarction patients (n=30 in each group) as well as in hematologic malignancies (n=42). The parameters assayed were: prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complexes (TAT), fibrinopeptide A (FPA), plasmin-alpha2 antiplasmin complexes (PAP) and D-Dimer. Results were compared with those obtained in a group of 30 healthy subjects. We found a significant increase of F1+2, TAT and FPA in elderly (p<0.05), acute myocardial infarction (AMI) (p<0.01), hematologic malignancies (p<0.01), and pregnancy (p<0.0001), indicating a marked clotting activation. Diabetic patients under strict metabolic control only presented a moderate increase of TAT (p<0.05), suggesting a slight activation. We also observed a highly significant elevation of PAP and D-Dimer in elderly (p<0.001), AMI (p<0.0001), and malignancy (p<0.0001), indicating an activation of the fibrinolytic system. The combination of selected fibrinolytic and coagulation measurements is useful for the detection of a hypercoagulable state in conditions characterized by a risk of thrombosis.

Haemocompatibility of paediatric membrane oxygenators with heparin-coated surfaces

Extracorporeal circulation (ECC) in paediatric patients with heparin-coated oxygenation systems is rarely investigated. The objective of this study was to evaluate, preclinically, the haemocompatibility of paediatric membrane oxygenators with heparin-coated surfaces. We compared 16 paediatric membrane oxygenators (Minimax, Medtronic) in an in vitro heart-lung machine model with fresh human blood. Eight of these oxygenation systems had a covalent heparin coating (Carmeda bioactive surface). After 90 min simulated ECC, the heparin-coated systems showed significantly higher platelet count, lower platelet-factor 4 release, reduced contact activation (factor XIIa and kallikrein), and lower neutrophil elastase levels (p < 0.05), compared to the noncoated oxygenator group. More biocompatible materials for paediatric operations may ameliorate the various postperfusion syndromes arising from ECC procedures, particularly unspecific inflammation, hyperfibrinolysis and blood loss.

High plasminogen activator inhibitor and tissue plasminogen activator levels in plasma precede a first acute myocardial infarction in both men and women: evidence for the fibrinolytic system as an independent primary risk factor

BACKGROUND

In patients with established ischemic heart disease, prospective cohort studies have indicated that plasminogen activator inhibitor (PAI-1), the inhibitor of the fibrinolytic system, may predict cardiovascular events. So far, there have been no primary prospective studies of PAI-1.

METHODS AND RESULTS

The aim of the present study was to test whether plasma levels of PAI-1, tissue-type plasminogen activator (tPA), von Willebrand factor (vWF), and thrombomodulin (TM) could predict the occurrence of a first acute myocardial infarction (AMI) in a population with high prevalence of coronary heart disease by use of a prospective nested case-control design. Mass concentrations of PAI-1 and tPA were significantly higher for the 78 subjects who developed a first AMI compared with the 156 references matched for age, sex, and sampling time; for tPA, this increase was independent of smoking habits, body mass index, hypertension, diabetes, cholesterol, and apolipoprotein A-I. The ratio of quartile 4 to 1 for tPA was 5.9 for a patient to develop a first AMI. The association between tPA and AMI was seen in both men and women. Increased levels of vWF were associated with AMI in a univariate analysis. High levels of TM were associated with AMI in women but not in men.

CONCLUSIONS

The plasma levels of PAI-1, tPA, and vWF are associated with subsequent development of a first AMI; for PAI-1 and tPA, this relation was found in both men and women. For tPA but not for PAI-1 and vWF, this association is independent of established risk factors.

Blood pressure and blood lipid levels among vegetarian, semi-vegetarian, and non-vegetarian native Africans

BACKGROUND

Several epidemiological studies have implicated hypercholesterolemia and hypertriglyceridaemia as a dietary risk factor in the etiology of vascular disease. To date, there are virtually no blood lipid data available for Negroid Black African Seventh-Day Adventist vegetarians. This study was undertaken to gain a preliminary and better understanding of the relationships between BP, blood lipids, and diets in adults at the Seventh-Day Adventist Seminary of West Africa, Ilisan-Remo, Nigeria.

METHODS

Three randomly selected groups of the Nigerian populace with different dietary habits were investigated. The Seventh-Day Adventist Seminary of West Africa was the study area. Anthropometric measurements, blood pressure, serum cholesterol, triglycerides, and serum glucose were estimated using standard methods.

FINDINGS

The vegetarians (VEGs) had significantly lower body weight 75.0 +/- 1.9 kg than the semi-vegetarians (SEMI-VEGs) 77.3 +/- 1.8 kg (p < 0.05). There was no significant difference between the blood pressure (BP) of the three groups studied, although the VEGs exhibited lower systolic BP. The VEGs had significantly lower serum total cholesterol and triglycerides (p < 0.05), than non-vegetarians (NON-VEGs). The SEMI-VEGs had blood triglycerides values in between NON-VEGs and VEGs levels but these were not significant. There were no differences in blood glucose in the three groups.

CONCLUSIONS

The vegetarian diet as well as the African natural diet are associated with lower levels of important cardiovascular disease risk factors. The significantly lower cardiovascular disease risk factors in vegetarian African Adventists could be a protective measure against the development of premature IHD and CVD incidence.

Influence of body fatness on the coronary risk profile of physically active postmenopausal women

We have shown previously that endurance-trained postmenopausal runners demonstrate more favorable coronary heart disease (CHD) risk factors compared with age-matched sedentary women. However, the runners exhibited higher levels of physical activity and lower levels of body fatness, both of which can influence CHD risk factors. To gain insight into the influence of body fatness per se, we studied 38 postmenopausal healthy women: 10 swimmers, 10 runners, and nine obese and nine leaner sedentary subjects matched for age, hormone replacement use, and years postmenopause. Swimmers and runners were further matched for exercise training volume (4.5+/-0.2 v 4.6+/-0.6 h/wk) and relative competitive performance (79%+/-5% v 77+/-3% of age-adjusted world record). Maximal oxygen consumption (VO2max) on the treadmill was lower (P < .01) in swimmers versus runners. Body mass (65.0+/-2.0 v 59.0+/-1.3 kg), percent body fat (29%+/-2% v 23%+/-2%), and waist circumference (79+/-3 v 71+/-1 cm) were greater (P < .01) in swimmers than in runners. There were no significant differences in total caloric intake or dietary composition between swimmers and runners. Insulin sensitivity (via Bergman's minimal model) and fasting plasma concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), glucose, and plasminogen activator inhibitor-1 (PAI-1) activity were not different between the groups. However, plasma high-density lipoprotein cholesterol (HDL-C), HDL2-C, HDL-C/TC, insulin, fibrinogen, fibrin D-dimer, PAI antigen, tissue plasminogen activator (t-PA) activity, and t-PA antigen levels all were less favorable (P < .05) in swimmers versus runners. Daytime, nighttime, and 24-hour systolic blood pressure (SBP) was 6 to 10 mm Hg higher in swimmers compared with runners, but resting blood pressure, 24-hour blood pressure load, and blood pressure variability were not significantly different. Stepwise regression showed that measures of body fatness were the primary independent determinants of most of the metabolic CHD risk factors. When analysis of covariance (ANCOVA) was performed with body fatness as a covariate, differences in CHD risk factors between swimmers and runners were abolished (P=.18 to .90). We conclude that among endurance-trained postmenopausal women matched for training volume and competitive eliteness, higher total and abdominal body fatness is, in general, associated with a less favorable metabolic CHD risk profile. Thus, high levels of habitual aerobic exercise do not appear to negate the deleterious effects of adiposity on the coronary risk profile of healthy middle-aged and older women.

Plasma remnant-like particle lipid and apolipoprotein levels in normolipidemic and hyperlipidemic subjects

Remnant-like particle (RLP) lipid and apolipoprotein (apo) levels were determined in the plasma of normolipidemic and hyperlipidemic subjects, in order to investigate the relationship between RLP levels and the concentration of other plasma lipoprotein parameters. Plasma RLP fractions were isolated with the use of an immunoaffinity gel (RLP-Cholesterol Jimro II, Japan Immunoresearch Lab.), containing specific anti-apoB-100 and anti-apoA-I antibodies. Four groups of human subjects were selected, who had either matching or significantly different levels of plasma triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C): (1) normolipidemic control (NC) subjects (n = 10), (2) patients with elevated levels of LDL-C (type IIa, LDL-C (mean +/- S.E.), 4.65 +/- 0.09 mmol/l, n = 10), (3) hypertriglyceridemic (HTG) patients with elevated LDL-C (type IIb, TG: 3.86 +/- 0.36; LDL-C: 4.67 +/- 0.21 mmol/l, n = 10), and (4) HTG patients with normal LDL-C (type IV, TG: 3.71 +/- 0.39 mmol/l, n = 10). NC subjects (RLP-C: 0.22 +/- 0.01; RLP-TG: 0.24 +/- 0.03 mmol/l) had RLP apoB, apoC-III and apoE levels of 3.2 +/- 0.3, 1.8 +/- 0.3, and 1.4 +/- 0.1 mg/dl, representing 3.2 +/- 0.4, 14.5 +/- 1.4 and 32.1 +/- 2.1% of total plasma levels, respectively. RLP lipid and apolipoprotein concentrations were significantly higher in HTG groups (type IIb and IV) compared to NTG groups (NC and type IIa) (e.g. RLP-C: 0.50 +/- 0.07 and 0.58 +/- 0.11 vs. 0.22 +/- 0.01 and 0.21 +/- 0.01 mmol/l, respectively (P < 0.01); RLP apoB: 8.4 +/- 1.6 and 8.2 +/- 0.9 vs. 3.2 +/- 0.3 and 3.4 +/- 0.2 mg/dl, respectively (P < 0.01)). No significant difference in RLP levels was observed between groups having different LDL levels, and thus no correlation existed between RLP-C and LDL-C levels (r = 0.24, n.s.). RLP-C and RLP apoB levels were, however, correlated with VLDL-C and VLDL apoB (r = 0.86, P < 0.001 and r = 0.70, P < 0.001, respectively). These results demonstrate that elevated levels of both RLP lipids and apolipoproteins are characteristic of patients with increased levels of plasma triglyceride, and not patients with increased levels of LDL.

Physical activity status and adverse age-related differences in coagulation and fibrinolytic factors in women

Adverse changes in coagulation and fibrinolytic factors are thought to contribute to the increased risk of cardiovascular disease and atherothrombosis with age. We tested the hypothesis that such age-related changes in specific coagulation and fibrinolytic factors are absent in physically active women. Resting levels of plasma fibrinogen, tissue-type plasminogen activator (t-PA) antigen and activity, plasminogen activator inhibitor-1 (PAI-1) antigen and activity, and fibrin D-dimer were measured in 24 healthy premenopausal women: 11 sedentary (aged 28+/-1 years; Pre-S) and 13 physically active (aged 30+/-1 years; Pre-PA) and in 27 healthy postmenopausal women: 14 sedentary (aged 61+/-1 years; Post-S) and 13 physically active (aged 58+/-1 years; Post-PA). Post-S had higher (P<.05) fibrinogen, t-PA antigen, PAI-1 antigen, PAI-1 activity, and fibrin D-dimer levels and lower t-PA activity than Pre-S. Post-PA demonstrated lower (P<.01) plasma fibrinogen, t-PA antigen, PAI-1 antigen, and PAI-1 activity and higher (P<.01) t-PA activity levels than Post-S. In addition, plasma fibrin D-dimer levels tended (P=.06) to be lower in Post-PA than in Post-S. Although plasma levels of fibrinogen and fibrin D-dimer in Post-PA were lower than in Post-S, they were higher (P<.05) than in Pre-PA. Importantly, however, the fibrinolytic profile of Post-PA did not differ from that of Pre-PA. The results of the present study demonstrate that the adverse age-associated differences in plasma fibrinogen concentrations and the endogenous fibrinolytic system in sedentary healthy women are either attenuated or absent in highly physically active women. The smaller or absent age-related differences in coagulation and fibrinolytic factors in women who habitually exercise may represent an important mechanism contributing to their lower age-related increase in both cardiovascular disease and atherothrombotic events. Future studies need to determine whether women who are moderately active would demonstrate the same favorable hemostatic profile.

Prevalence of double pre-beta lipoproteinemia in hyperlipidemic patients is influenced by gender, menopausal status, and ApoE phenotype

Double pre-beta lipoproteinemia (DPBL) is a plasma lipoprotein phenotype characterized by the presence of two agarose gel electrophoretic populations of very low density lipoproteins (VLDLs, d < 1.006 g/mL), i.e., normal pre-beta-migrating VLDL and slow pre-beta VLDL. Slow pre-beta VLDL represents remnant lipoproteins derived from the hydrolysis of triglyceride (TG)-rich lipoproteins (TRLs), and thus DPBL is a characteristic of plasma remnant lipoprotein accumulation. To determine the prevalence of DPBL in our lipid clinic population, patients (n = 2501) were selected who (1) had an unambiguous VLDL electrophoretic phenotype and could be classified as having either DPBL (DPBL+), beta-migrating VLDL (beta-VLDL +), or an absence of both (DPBL/beta-VLDL-/-) and (2) had hypercholesterolemia (HC: plasma cholesterol > or = 6.2 mmol/L, n = 1017), hypertriglyceridemia (HTG: plasma TG > or = 2.3 mmol/L but < 15 mmol/L, n = 554) or combined hyperlipidemia (HC + HTG, n = 930). Patients with TG < 2.3 mmol/L and cholesterol < 5.2 mmol/L acted as control subjects (n = 343). Using a commercially available agarose gel electrophoresis system, we identified 220 hyperlipidemic patients (8.8%) with DPBL (versus < 1% of control). The prevalence of DPBL was higher in (1) male than in female patients (10.7% versus 6.7%), (2) postmenopausal than in premenopausal females (7.3% versus 4.1%), and (3) patients with HC + HTG than in those with HTG or HC alone (15.8% versus 8.3% versus 2.7%, respectively). Patients with an epsilon 2 allele had a higher prevalence of DPBL; i.e., 26.9% of apoE 3/2 and 26.2% of apoE 4/2 patients had DPBL compared with 6.5%, 6.8%, and 7.4% of apoE 3/3, 4/3, and 4/4 patients, respectively. DPBL patients consistently had increased levels of VLDL-C and (LDL + HDL)-TG and decreased levels of LDL-C, and their plasma lipid profiles were intermediate between those of beta-VLDL+ and DPBL/beta-VLDL -/- patients. These results demonstrate that male sex, postmenopausal status in women, and the presence of an apoE 3/2 or apoE 4/2 phenotype are associated with an increased incidence of DPBL in hyperlipidemic patients.

Albuminuria is directly associated with increased plasma PAI-1 and factor VII levels in NIDDM patients

Increased plasma plasminogen activator inhibitor type 1 (PAI-1), coagulation factor VII (FVII) and fibrinogen levels have been recognized as risk factors for cardiovascular disease. Because a substantially high incidence of cardiovascular disease has been reported in diabetic patients with nephropathy compared with those without nephropathy, we measured plasma levels of PAI-1, FVII activity and fibrinogen in non-insulin-dependent diabetic patients (NIDDM) with normoalbuminuria (without nephropathy), microalbuminuria (incipient nephropathy) and macroalbuminuria (overt nephropathy). PAI-1 and FVII levels were significantly increased in NIDDM with overt nephropathy compared with NIDDM without nephropathy. Fibrinogen levels were comparable between the patients with normo-, micro- and macro-albuminuria. Univariate regression analysis indicated that PAI-1 and FVII levels were significantly correlated with the albumin excretion rate (AER) in urine. PAI-1, FVII and fibrinogen levels were significantly correlated with the degree of insulin resistance estimated by the steady state plasma glucose concentration (SSPG) during the continuous infusion of glucose, insulin and octreotide. PAI-1 levels were correlated with plasma triglyceride (TG) levels. Multiple regression analysis revealed that AER was significantly associated with PAI-1 and FVII levels, whereas TG lost significant correlation with PAI-1 when AER, SSPG and plasma TG were entered as independent variables. SSPG retained an independent correlation with fibrinogen, PAI-1 and FVII levels. These results suggest that elevated plasma levels of PAI-1 and FVII in NIDDM patients with nephropathy are directly associated with renal damage, whereas insulin resistance widely regulates hemostatic components in NIDDM patients, irrespective of the presence of nephropathy.