Coagulation and inhibitory and fibrinolytic proteins in essential hypertension

Plasma D-dimer levels are correlated with disease severity among hypertensive patients: A comparative cross-sectional study

It has been reported that inappropriate acute thrombus formation is the pathophysiological substrate underlying increased risk and severity of target organ damage in hypertension (HTN). However, the relationship between severity of HTN and D-dimer has not been well characterized. The study was aimed to assess plasma D-dimer level and its correlation with disease severity among hypertensives. A comparative cross-sectional study was conducted at Wuhan Asia Heart Hospital among 100 participants (60 hypertensives and 40 controls). The correlation between variables were determined using correlation coefficients, regression analysis, and also using different parametric and nonparametric tests. We observed higher D-dimer levels among hypertensives compared to the healthy controls (P < .001). The D-dimer levels were found to be increased significantly with the severity of HTN (P < .001). D-dimer was found to have a diagnostic power of 86.9% in differentiating complicated from uncomplicated HTN at 0.83 mg/L cutoff value. This study suggests that D-dimer level was higher among hypertensives than control groups and it was also increasing significantly with the severity of HTN. This suggests that hypercoagulability of fibrin plays a role in the occurrence of thromboembolic complications of hypertensive patients.

Plasma Exosomal Proteomic Pattern of Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis

Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a life-threatening syndrome, which is caused by EBV infection that is usually refractory to treatment and shows relapse. The development of new biomarkers for the early diagnosis and clinical treatment of EBV-HLH is urgently needed. Exosomes have been shown to mediate various biological processes and are ideal non-invasive biomarkers. Here, we present the differential plasma exosomal proteome of a patient with EBV-HLH before vs. during treatment and with that of his healthy twin brother. A tandem mass tag-labeled LC-MS technique was employed for proteomic detection. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that differential proteomic profiles were related to virus infection, coagulopathy, nervous system dysfunction, imbalance of immune response, and abnormal liver function. The candidate biomarkers were first identified in the patient’s plasma exosomes at different treatment and follow-up time points. Then, 14 additional EBV-HLH exosome samples were used to verify six differentially expressed proteins. The upregulation of C-reactive protein, moesin, galectin three-binding protein, and heat shock cognate 71 kDa protein and the downregulation of plasminogen and fibronectin 1 could serve as potential biomarkers of EBV-HLH. This plasma exosomal proteomic analysis provides new insights into the diagnostic and therapeutic biomarkers of EBV-HLH.

The association between endothelial dysfunction and hypertensive retinopathy in essential hypertension

BACKGROUND

Endothelial dysfunction, which is characterized by an imbalance between relaxing and contracting factors, procoagulant and anticoagulant substances, and between pro-inflammatory mediators, may play a particularly significant role in the pathogenesis of atherosclerosis. Numerous experimental and clinical reports suggest that a high von Willebrand factor (vWF) level reflects endothelial damage or dysfunction. Hypertensive retinopathy (HR) is a condition characterized by a spectrum of retinal vascular signs in people with elevated blood pressure. The pathophysiological mechanism of HR is not completely understood. Elevated blood pressure alone does not fully account for the extent of retinopathy. Endothelial dysfunction and mechanisms known to be involved in vascular lesions may be involved in the pathophysiological mechanism of HR. Therefore, this study was designed to answer the following questions: (i) Do vWf levels change in HR? and (ii) Is there any relation between degree of HR and vWf levels?

MATERIAL AND METHODS

This study included 80 hypertensive patients with HR. Group 1 comprised 40 patients with grade I HR, and group 2 comprised 40 patients with grade II HR. We selected 40 healthy subjects for the control group.

RESULTS

Level of vWf in group 2 was significantly higher than in group 1 (p=0.017) and the control group (p<0.001), and it was also higher in group 1 than in the control group (p<0.005). Also, vWf showed positive correlation with degree of HR in the hypertensive group (r=0.284, p=0.009).

CONCLUSIONS

Our study suggests that endothelial dysfunction, which is a mechanism known to be involved in vascular lesions, may promote the development of HR.

Haemostatic factors in women with history of preeclampsia

OBJECTIVE

Evaluation of haemostatic parameters--Plasma tissue plasminogen activator (t-PA), plasminogen activator inhibitor type 1 (PAI-1) and fibrin fragment D-dimer several years after the end of pregnancy to investigate if they are modified in women with history of preeclampsia (PE).

STUDY DESIGN

65 healthy women with history of PE and 54 control women with previous normal pregnancy were enrolled in this study. Groups were matched for age, time period since delivery, smoking status and alcohol consumption. t-PA, PAI-1 and fibrin fragment D-dimer antigen levels were quantified using standards commercial ELISA methods. Plasma fibrinogen was measured using automated capillary zone electrophoresis.

RESULTS

Systolic and diastolic blood pressures were higher in women with history of PE. Levels of t-PA, PAI-1 and fibrinogen were similar between groups as well as the t-PA/PAI-1 ratio. A significant increase in D-dimer levels was observed in women with history of PE.

CONCLUSION

The increase in D-dimer level suggests an abnormal haemostatic potential namely increased intravascular coagulation. This, together with the increased blood pressure, can reflect a tendency for an increased risk of cardiovascular/thrombotic events later in life.

New risk factors for atherosclerosis in hypertension: focus on the prothrombotic state and lipoprotein(a)

Although adequate control of blood pressure is of basic importance in cardiovascular prevention in hypertensive patients, correction of additional risk factors is an integral part of their management. In addition to classical risk factors, epidemiological research has identified a number of other conditions that might significantly contribute to cardiovascular risk in the general population and might achieve specific relevance in patients with high blood pressure. In fact, more than 20% of patients with premature cardiovascular events do not have any of the traditional risk factors and, although effective intervention on blood pressure and additional risk factors has significantly reduced cardiovascular morbidity and mortality, the contribution to stroke, coronary artery disease and renal failure is still unacceptably high. Evaluation of new risk factors may further expand our capacity to predict atherothrombotic events when these factors are included along with the traditional ones in the assessment of global cardiovascular risk in hypertensive patients. Because it could be anticipated that the role of these novel factors will become increasingly evident in the future, researchers with an interest in hypertension and physicians dealing with problems related to cardiovascular prevention should give them appropriate consideration. This review summarizes the basic biology and clinical evidence of two emerging risk factors that are reciprocally related and contribute to the development and progression of organ damage in hypertension: the prothrombotic state and lipoprotein(a).

The hypercoagulable state in sleep apnea is related to comorbid hypertension

OBJECTIVE

Obstructive sleep apnea (OSA) is associated with increased prevalence of atherosclerotic disease. A hypercoagulable state thought to underly atherosclerosis has been described in both OSA and systemic hypertension. We wondered about the respective contribution of apnea and hypertension to a hypercoagulable state.

DESIGN

Eighty-seven subjects with symptoms suggestive of OSA, mean age 47 years (range 32-64 years), underwent polysomnography and blood pressure (BP) screening. OSA was diagnosed when respiratory disturbance index (RDI) > or = 15. Subjects having systolic BP (SBP) > 140 mmHg and/or diastolic BP (DBP) > 90 mmHg were classified as having hypertension. Three hypercoagulability markers were measured: thrombin/antithrombin III complex (TAT), fibrin D-dimer (DD), and von Willebrand factor antigen (vWF:ag).

RESULTS

Analysis of variance and multiple linear regression were performed on the following four subject groups: (1) normotensive non-apneics (n = 19), (2) normotensive apneics (n = 38), (3) hypertensive non-apneics (n = 11), and (4) hypertensive apneics (n = 19). OSA (groups 2 and 4) had no significant main effect on hemostasis. Hypertensives (groups 3 and 4) had higher plasma levels of TAT (median/inter-quartile range, 148/59-188 versus 77/53-108 pmol/l; P = 0.009) and of DD (376/265-721 versus 303/190-490 ng/ml; P = 0.040) than normotensives (groups 1 and 2). Across all subjects, SBP was the only significant predictor of TAT (P = 0.001) and of DD (P = 0.004), whereas DBP was the only significant predictor of vWF:ag (P = 0.029). These findings persisted even after controlling for gender, age, body mass index, RDI, mean SaO2, and hematocrit.

CONCLUSION

Hypercoagulability in OSA is mediated by comorbid hypertension and might account for high cardiovascular morbidity in OSA in general.

Pathophysiology of oxidative stress in diabetes mellitus

Oxidative stress is believed to play an important role, albeit not fully recognized, in the development of vascular complications in diabetes mellitus (DM) particularly type 2. In the majority of studies, attention was focused on lipid oxidation, specifically on that of low-density lipoproteins (LDLs). More recent investigations have revealed that it is not only the lipid but also the apolipoprotein moiety of LDL that becomes oxidatively modified resulting in the formation of insoluble aggregates. Consequently, it has been documented that LDL aggregation was due to the hydroxyl radical-induced dityrosine crosslinking between apo B monomers. In DM patients with atherosclerotic complications, intravascular fibrous deposits were shown to contain, in addition to oxidized LDL, a fibrin-like material (FLM). This material is immunologically identical to fibrin that is normally formed as a result of intravascular activation of the blood coagulation cascade. Although DM patients with vascular disease display increased concentration of plasma fibrinogen (Fbg), the precursor of fibrin, no markers of full blown activation of blood coagulation could be found.

Relationship of lipoprotein(a) to variables of coagulation in hypertensive subjects

BACKGROUND

Coagulation factors are independent predictors of cardiovascular damage in the general population. The purpose of this study was to investigate the relationships between general cardiovascular risk factors, lipoprotein(a) (Lp(a)), and some hemostatic variables, and to characterize the isoforms of apolipoprotein(a) (apo(a)) in hypertensive subjects.

METHODS

Plasma lipids, apolipoproteins, Lp(a), apo(a) isoforms, fibrinogen, and parameters that directly reflect the coagulation activation were measured in 389 untreated essential hypertensive patients recruited at a hypertension clinic. Hypertensive patients were compared with 323 normotensive controls.

RESULTS

In normotensive subjects, Lp(a) concentrations were significantly correlated with fibrinogen (r = 0.138; P < 0.02) but not D-dimer (r = 0.074; not significant). In hypertensive subjects, log Lp(a) concentrations were significantly correlated with age (r = 0.127; P < 0.02), apo-B (r = 0.128; P < 0.02), plasma fibrinogen (r = 0.193; P < 0.001), and fibrin D-dimer (r = 0.200; P < 0.001) levels, but not with body mass index, blood pressure, cholesterol, triglycerides, apo-AI, prothrombin fragment 1 + 2, and antithrombin III. The relationship of Lp(a) with fibrinogen (male: r = 0.198, P < 0.002; female: r = 0.177, P < 0.01) and D-dimer (male: r = 0.211, P < 0.002; female: r = 0.188, P < 0.01) was significant in both sexes, whereas the relationship of Lp(a) with age and apo-B was found only in males. Multivariate analysis showed that both fibrinogen and D-dimer were independently related with Lp(a). Elevated fibrinogen, D-dimer, and Lp(a) levels were significantly and independently associated with clinical evidence of atherosclerotic disease. Apo(a) phenotypes were analyzed to investigate the genetic background of the relationships between Lp(a) and coagulation parameters. In both hypertensive and normotensive subjects, Lp(a) levels were inversely correlated with apo(a) isoform protein size, whereas fibrinogen and D-dimer concentrations were comparable in patients with apo(a) isoforms of different size.

CONCLUSIONS

The relationship between Lp(a) and clotting variables is significantly stronger in hypertensive than in normotensive subjects, providing a compelling argument for accelerated progression of atherothrombosis in these patients.

Relationship of fibrinogen levels and hemostatic abnormalities with organ damage in hypertension

Elevated plasma levels of fibrinogen and activated coagulation pathways are risk factors of cardiovascular disease in the general population. In a cross-sectional study of a case series, we investigated the relationship between fibrinogen and hemostatic markers with target-organ damage (TOD) in patients with arterial hypertension. Prothrombin time, partial thromboplastin time, fibrinogen, fibrin D-dimer, prothrombin fragment 1+2 (F1+2), and antithrombin III were measured in 352 untreated patients with mild to moderate essential hypertension and 92 normotensive controls. Staging of TOD was assessed according to W.H.O. guidelines by clinical evaluation and laboratory tests including measurements of creatinine clearance, proteinuria, ophthalmoscopy, electrocardiography, echocardiography, and ultrasound examination of major arteries. F1+2 concentrations were significantly greater in hypertensive patients than normotensive controls and were positively correlated with blood pressure. Age, blood pressure levels, duration of hypertension, smoking, HDL-cholesterol, triglycerides, and plasma fibrinogen, fibrin D-dimer, and F1+2 levels were significantly related to the presence and severity of TOD in univariate analysis. Plasma fibrinogen and D-dimer levels were related to organ damage independent of age, blood pressure, duration of hypertension, and smoking status. Separate analysis indicated significant association of fibrinogen and D-dimer levels with cardiac, cerebrovascular, peripheral vascular, and renal damage. In conclusion, elevated plasma levels of fibrinogen and a prothrombotic state are associated with the presence and severity of TOD in patients with essential hypertension and may contribute to the development of atherosclerotic disease in these patients.

Lipoprotein (a), haemostatic variables and cardiovascular damage in hypertensive patients

OBJECTIVE

Lipoproteins and coagulation factors are independent predictors of atherothrombotic events in the general population and their interaction may contribute to the development of cardiovascular damage. This study was designed to assess relationships between lipoproteins, haemostatic variables, and atherosclerotic complications in hypertensive patients.

METHODS

In 389 untreated essential hypertensive patients recruited at a hypertension clinic, we measured plasma lipids, apolipoproteins, lipoprotein (a), apolipoprotein (a) isoforms, fibrinogen, and parameters that directly reflect the coagulation activation. Hypertensive patients were compared to 92 normotensive controls.

RESULTS

Univariate analysis showed log lipoprotein (a) concentrations to be significantly correlated with age (P< 0.02), apolipoprotein B (P< 0.02), plasma fibrinogen (P< 0.001), and fibrin D-dimer (P< 0.001) levels, but not with body mass index, blood pressure, dietary fat intake, cholesterol, triglycerides, apolipoprotein Al, prothrombin fragment 1 + 2, and antithrombin III. The relationship of lipoprotein (a) with fibrinogen and D-dimer was present in both sexes, whereas the relationship of lipoprotein (a) with age and apolipoprotein B was found only in males. Multiple regression analysis showed that both fibrinogen and D-dimer were independently related with lipoprotein (a). Elevated fibrinogen, D-dimer, and lipoprotein (a) levels were significantly and independently associated with clinical evidence of atherosclerotic disease. To investigate whether the relationships of lipoprotein (a) with coagulation parameters are genetically determined, we analysed apolipoprotein (a) phenotypes in a subset of 188 hypertensive patients. While lipoprotein (a) levels were inversely correlated with apolipoprotein (a) isoform protein size, both fibrinogen and D-dimer concentrations were comparable in patients with apolipoprotein (a) isoforms of different size.

CONCLUSIONS

This study demonstrates a relationship between lipoprotein (a) and clotting variables in hypertensive patients that may contribute to atherosclerotic damage in these patients. There is no evidence of a genetic background for this relationship.

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.

Does hypertension confer a hypercoagulable state?

Although the blood vessels are exposed to high pressures in hypertension, the main complications of hypertension (stroke and myocardial infarction) are paradoxically thrombotic rather than haemorrhagic. In keeping with Virchow's triad, patients with hypertension do demonstrate abnormalities of vessel wall (endothelial dysfunction or damage), blood constituents (abnormal levels of haemostatic factors, platelet activation and fibrinolysis) and blood flow (rheology and flow reserve), suggesting that hypertension does confer a prothrombotic or hypercoagulable state. These abnormalities appear to be related to target organ damage and long-term prognosis and are altered by treatment. The observation that satisfactory blood pressure reduction with non-drug intervention and with various classes of antihypertensive drugs does not lead to an equal reduction in heart attacks and strokes may be due in part to unfavourable effects on the hypercoagulable state in hypertension. Antihypertensive agents with particular benefits in reducing this hypercoagulable state would be likely to have additional advantages in reducing the occurrence of stroke and other thromboembolic events.

Haemostasis balance disorders in patients with essential hypertension

This study was aimed at investigating haemostasis parameters in patients (pts) with arterial hypertension (AH) before any medical treatment and to correlate these findings with those in healthy normal Greek population 83 pts (48 m, 35 w) mean age 49.8 +/- 10.1 yrs, body mass index 23.4 +/- 1.5 with mild to moderate AH and 42 healthy volunteers matched for sex (24 m, 18 w), age 51.2 +/- 10.5 yrs and body mass index 22.8 +/- 1.46 were studied. Fibrinogen, vWF, plasminogen, ECLT, a2 antiplasmin, tPA-Ag, PAI-1 in all pts and in the control group were measured. Mean age and BMI did not significantly differ between the two groups. The hypertensive patients had significantly higher levels of fibrinogen (327.75 +/- 51.36 vs. 272.84 +/- 46.8 mg/dl), tPA-Ag (8.81 +/- 3.32 vs. 5.76 +/- 2.54 ng/ml) and PAI-1 (11.8 +/- 10.9 vs. 7.91 +/- 5.5 IU/ml), whereas a2 antiplasmin level was significantly lower (98.71 +/- 15.40 vs. 107.84 +/- 17.52%). No differences were found between hypertensives and normal subjects in vWF, plasminogen and ECLT. These preliminary data suggest that in pts with mild to moderate AH, before any medical treatment, there are significantly higher levels of fibrinogen, tPA-Ag and PAI-1 compared with normal volunteers, whereas there are significantly lower a antiplasmin levels. These findings indicate a disturbance in the haemostasis balance with hypercoagulability and fibrinolytic deficiency.

Increased levels of tissue plasminogen activator antigen in essential hypertension. A population-based study in Sweden

OBJECTIVE

To investigate components of the haemostatic and fibrinolytic system in borderline hypertensives and hypertensives, drug-treated or not, from a defined population.

DESIGN AND METHODS

A randomly selected sample of the population of northern Sweden, 1558 subjects aged 25-64 years, was studied. Eight per cent of them were being treated with antihypertensive drugs (trHT). Remaining subjects were classified according to their mean diastolic blood pressure (DBP). Normotension, DBP < 85 mmHg, was found in 63%, borderline hypertension (bHT), DBP 85-94 mmHg, in 21% and untreated hypertension (uHT), DBP > or = 95 mmHg, in 8% of the subjects.

RESULTS

Mean age increased from the normotensive group through the bHT and uHT groups to the trHT group, members of which were the oldest. Age-adjusted values for the body mass index, waist: hip ratio, serum triglyceride and Phadeseph plasma insulin levels increased with each level of hypertension. Plasma fibrinogen levels and plasminogen activator inhibitor type 1 activity (in men) increased stepwise from normotensives through bHT and uHT to the highest values found in the trHT group. The tissue plasminogen activator (tPA) activity in men declined strongly across the groups, trHT having the lowest fibrinolytic activity (P < 0.001). tPA antigen levels increased strongly from normotensives through bHT to uHT, but then were lower in the trHT group. Even after adjustment for possible confounders, men in the uHT group had 21% higher (P = 0.027) tPA antigen levels than did the normotensives. In bHT men, the tPA antigen and plasminogen activator inhibitor type 1 activities were 14 and 24% respectively, higher (P < 0.01) than those in the normotensives.

CONCLUSION

Hypertension is associated with multiple metabolic and fibrinolytic disturbances that are accentuated in drug-treated hypertensives and already discernible in subjects with borderline hypertension. Decreased fibrinolysis is associated with, and possibly secondary to, metabolic disturbances linked to the insulin-resistance syndrome. The independent increase in tPA antigen in hypertensive men might indicate an endothelial dysfunction.

von Willebrand factor and its relevance to cardiovascular disorders

In the past decade the importance of the vascular endothelium in cardiovascular pathophysiology has become more apparent. One substance that is synthesised by and stored in endothelial cells is von Willebrand factor (vWF). When released, vWF seems to mediate platelet aggregation and adhesion to the vascular endothelium. Because the release of vWF is increased when endothelial cells are damaged, vWF has been proposed as an indicator of endothelial disturbance or dysfunction. The availability of such an index of endothelial dysfunction may have clinical value, because measurement of such a marker can be a non-invasive way of assisting in diagnosis or as an indicator of disease progression. The known association between vWF, thrombogenesis, and atherosclerotic vascular disease also suggests that high concentrations of vWF may be an indirect indicator of atherosclerosis and/or thrombosis. In addition, high vWF concentrations have prognostic implications in patients with ischaemic heart disease and peripheral vascular disease.

Determinants of fibrin D-dimer in the Edinburgh Artery Study

There is growing evidence that fibrin D-dimer is associated with coronary and peripheral atherosclerosis. Using data from the Edinburgh Artery Study, we examined the distribution of fibrin D-dimer in 1592 men and women 55 to 74 years old and assessed its relationship with a range of cardiovascular risk factors. Fibrin D-dimer levels were higher in women than in men (P < or = .05) and increased with age (P < or = .001). Current cigarette smokers had higher levels than ex-smokers, who, in turn, had higher levels than those who had never smoked. On multiple regression analyses with age and plasma fibrinogen as covariates, only lifetime smoking in men and systolic blood pressure in women were independent predictors of fibrin D-dimer levels. Since fibrin D-dimer does not appear to be independently related to many of the common cardiovascular risk factors, it may be a useful index of the thrombotic contribution to arterial disease.

Blood coagulation, fibrinolytic, and inhibitory proteins in end-stage renal disease: effect of hemodialysis

Patients with end-stage renal disease (ESRD) are at risk of ischemic cardiovascular complications and vascular thrombosis. These observations prompted the present survey of the blood coagulation, fibrinolytic, and inhibitory proteins in a group of 31 ESRD patients and 32 normal controls. Immunologic and functional assays were used to quantitate plasma antigen concentrations and/or functional activities of factors XII, XI, IX, VIII, VII, X, II, and XIII, von Willebrand factor, fibrinogen, fibronectin, high molecular weight kininogen, D-dimer, antithrombin III, protein C, protein S, plasminogen, tissue-type plasminogen activator, plasminogen activator inhibitor, alpha 2-antiplasmin, alpha 1-antitrypsin, and alpha 2-macroglobulin as well as antiplasmin activity. The coagulant activities of factors XII, IX, X, and II were significantly reduced in ESRD patients despite their normal or increased plasma antigen concentrations. In addition, the ESRD patients showed hyperfibrinogenemia and significant elevations of plasma concentrations of D-dimer, von Willebrand factor, factor VII, and factor XIII antigens. They also exhibited significant reductions of antithrombin III, free protein S, plasminogen, and tissue-type plasminogen activator concentrations. Despite ultrafiltration, plasma factor IX activity and von Willebrand factor and fibrinogen concentrations decreased after hemodialysis with little or slight changes in other measured parameters. The ESRD patients studied here exhibited numerous abnormalities of coagulation, fibrinolytic, and inhibitory proteins at multiple levels. These abnormalities may be involved in the pathogenesis of cardiovascular complications and vascular thrombosis in this population. The precise mechanism(s) and clinical significance of the observed abnormalities are unknown and await further investigation.