Endothelial damage and angiogenesis in hypertensive patients: relationship to cardiovascular risk factors and risk factor management

BACKGROUND: Hypertensive patients are at particular risk of cardiovascular complications, possibly related to endothelial damage or dysfunction, or to abnormal angiogenesis. These pathophysiologic processes are assessable by measurement of plasma levels of von Willebrand factor (vWf), and by vascular endothelial growth factor (VEGF) and its soluble receptor (sFlt-1). We hypothesized that these markers would correlate with the Framingham cardiovascular risk score and would be responsive to treatment. METHODS: We measured these markers by enzyme-linked immunosorbent assay in 286 patients with hypertension (239 men; mean age 63 years; mean systolic blood pressure [BP]/diastolic BP 162/89 mm Hg) and additional risk factors, and related them to the patient's cardiovascular disease (CVD) and cerebrovascular accident (CVA) risk, using the Framingham equation. Patients were compared with 60 healthy normotensive controls. In 248 patients, the effects of 6 months of intensified cardiovascular risk factor management, including BP and (where appropriate) lipid-lowering treatment, were investigated. RESULTS: Plasma VEGF and vWf levels were higher, but sFlt-1 levels lower (all P <.001), in the hypertensive patients compared with the controls. The VEGF and vWf levels correlated significantly with age, systolic and diastolic BP, 10-year CVD risk, and CVA risk scores (all P <.01), whereas sFlt-1 was negatively correlated with these risk scores (P <.01). After intensified cardiovascular risk factor management, total cholesterol, BP, VEGF, and vWf levels were all reduced, yet sFlt-1 levels increased (all P <.05). CONCLUSIONS: In hypertension, the processes of endothelial damage and angiogenesis are abnormal, and correlate with overall cardiovascular risk. Indices of endothelial damage and angiogenesis are beneficially changed by intensive cardiovascular risk factor management.     

Haemorheological, platelet and endothelial indices in relation to global measures of cardiovascular risk in hypertensive patients: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial

INTRODUCTION AND METHODS: We tested the hypothesis that there was a significant relationship between haemorheological markers [white blood cell count (WCC), plasma viscosity (PV), haematocrit (HCT) and fibrinogen], as well as plasma von Willebrand factor (vWf, an index of endothelial damage/dysfunction) and soluble P-selectin (sP-sel, an index of platelet activation), to five global measures of cardiovascular risk [i.e. Framingham coronary heart disease (CHD), stroke and cardiovascular death score, the Pocock cardiovascular risk score and the sum of individual risk factors]. RESULTS: Men with a high (> or = median, n = 156) Framingham 10-year CHD risk score had higher levels of WBC (P = 0.027), fibrinogen (P = 0.012) and vWF (P = 0.002) than 153 men with results < median. Men with a high 10-year stroke risk score had significantly higher levels of fibrinogen (P = 0.01) and vWF (P < 0.0001). In stepwise linear regression analysis in men, vWF and fibrinogen were independent predictors of the number of risk factors (P < 0.0001), whilst WCC, vWF and fibrinogen emerged as independent predictors of Framingham CHD risk (P < 0.0001), and fibrinogen and vWF predicted Framingham stroke risk (R(2) = 0.089, P < 0.0001). vWF, PV and fibrinogen were predictors of Pocock cardiovascular death risk (P < 0.0001) but vWF was the only independent predictor of Framingham cardiovascular death risk (P = 0.001). CONCLUSIONS: Abnormal haemorheological factors (particularly high plasma fibrinogen levels) and endothelial damage/dysfunction (high vWF), but not platelet activation (sP-sel), are related to established cardiovascular and death risk scores. This relationship was most evident amongst male 'high-risk' hypertensive subjects.     

The effect of multi-factorial intervention on plasma von Willebrand factor, soluble E-selectin and tissue factor in diabetes mellitus: implications for atherosclerotic vascular disease.

BACKGROUND: Endothelial abnormalities and a hypercoagulable state may contribute to increased cardiovascular risk in diabetes mellitus, particularly in patients with overt cardiovascular disease (CVD). We sought to determine the effect of intensified multi-factorial cardiovascular risk intervention on indices of endothelial abnormality and hypercoagulability in diabetes, and if patients with overt CVD would derive similar benefit as those without. PATIENTS AND METHODS: We measured plasma von Willebrand factor (vWf, an index of endothelial damage/dysfunction), soluble E-selectin (sE-sel, marking endothelial activation) and tissue factor (TF, an initiator of coagulation) by ELISA in 94 patients with diabetes mellitus (38 with CVD and 56 without overt CVD) and 34 comparable controls. Thirty-three patients with CVD and 31 without overt CVD then participated in multi-factorial cardiovascular risk intervention over 1 year. RESULTS: Plasma levels of vWf (P = 0.009), sE-sel (P < 0.001) and TF (P < 0.001) were significantly higher in diabetic patients compared with controls, with TF highest in patients with overt CVD. Intensive multi-factorial intervention resulted in reductions in glycated haemoglobin (HbA(1c)), total and LDL-cholesterol (all P < 0.05), but no significant weight change. This was associated with reductions in vWf in patients with (by 26%P = 0.003), and without (by 47%, P < 0.001), overt CVD. TF was reduced only in patients without overt CVD (by 45%, P < 0.001). There were no significant changes in sE-sel levels in either group. CONCLUSION: Endothelial abnormalities in diabetes are only partially influenced by contemporary intensified multi-factorial cardiovascular risk intervention. These data suggest the need for earlier and more aggressive risk factor intervention.     

Biomarkers of endothelial dysfunction are elevated and related to prognosis in chronic heart failure patients with diabetes but not in those without diabetes

BACKGROUND: Biomarkers of endothelial dysfunction, such as soluble E-selectin, and von Willebrand factor (vWf) are elevated in patients with chronic heart failure (CHF). The impact of diabetes mellitus (DM) on these biomarkers, and their relation to prognosis remains unknown. AIMS: to investigate the impact of DM on plasma levels and the prognostic value of E-selectin and vWf in patients with CHF. METHODS AND RESULTS: Plasma levels of E-selectin and vWf were measured in 195 CHF patients with (n=48, 24.5%), and without DM, and in 116 age-matched healthy controls. Compared with controls, median plasma E-selectin levels were higher in CHF patients with DM (P=0.012), but not in CHF patients without DM (P=0.45); vWf levels were also higher in CHF patients with DM (P<0.001), but not without DM (P=0.108). E-selectin was associated with risk of recurrent ischaemic cardiovascular events among CHF patients with DM (HR 2.60; P=0.009), but not among patients without DM (HR 1.09; P=0.60) per 1 SD increment in log transformed variable. vWf was not related with outcome in CHF patients with or without DM. CONCLUSIONS: Plasma levels of E-selectin and vWf are elevated in CHF patients with DM but not in those without DM. High E-selectin levels may be associated with ischaemic events in patients with DM.     

Asymmetric dimethyl arginine levels correlate with cardiovascular risk factors in patients with erectile dysfunction

BACKGROUND: Erectile dysfunction is related to penile arterial endothelial nitric oxide production. Asymmetric dimethylarginine (ADMA) and E-selectin are often considered plasma markers of endothelial function. OBJECTIVE: This study investigated the relationship between these plasma markers and cardiovascular risk factors in patients with erectile dysfunction. METHODS AND RESULTS: Cardiovascular risk factors, ADMA and E-selectin were assessed in 45 patients with erectile dysfunction. Plasma markers showed associations with baseline risk factors. E-selectin levels showed an inverse relationship with age (p = 0.005) and statin therapy (p = 0.03) and a weak association with concomitant beta-blocker therapy (p = 0.05). Compared to these relatively weak associations with cardiovascular risk factors, ADMA levels showed strong associations with pulse pressure (p < 0.001), lack of smoking (p = 0.002) and lipoprotein (a) (p = 0.004) concentrations and weak associations with LDL-cholesterol (p = 0.02), and C-reactive protein levels (p = 0.04). ADMA levels correlated with E-selectin (partial r = 0.76; p < 0.001) after adjustment for lipoprotein (a), pulse pressure and smoking. No change in E-selectin or ADMA levels was seen after 70 days therapy with sildenafil and no relationship was found between either plasma marker and the acute pulse wave response to a single challenge dose of sildenafil. CONCLUSION: ADMA levels correlate at baseline with some cardiovascular risk factors including inflammatory markers and lipoprotein (a) in patients with erectile dysfunction.     

Is mild essential hypertension without obvious organ complications and risk factors associated with increased levels of circulating markers of endothelial dysfunction? Effect of ACE inhibitor therapy

The objective of the investigation was to assess whether circulating adhesion molecules, von Willebrand factor (vWf) and endothelin-1 are elevated in patients with mild uncomplicated essential hypertension without further risk factors of atherosclerosis and whether they could serve as indicators of endothelial dysfunction in this form of hypertension. Furthermore the authors investigated the effect of ACE inhibitor treatment (ACEI), quinapril, on the level of these markers of endothelial dysfunction. The level of adhesion molecules [intercellular cytoadhesion molecule-1 (ICAM-1), E-selectin, P-selectin], von Willebrand s factor (vWf) and endothelin-1 were assessed in patients with mild essential hypertension without further cardiovascular risk factors or clinical manifestations of atherosclerosis before and after quinapril treatment (n = 25) and compared with normotensive controls (n = 29). The results of the examinations provided evidence that contrary to controls the hypertensive subjects had significantly higher ICAM-1 levels (237.8 vs. 207.8 ng/ml, P = 0.02) vWf (118 vs. 106 IU/dl, p < 0.05) and endothelin-1 (5.81 vs. 5.15 fmol/ml, p < 0.05). Three-month treatment of hypertensive patients with ACEI led to a significant drop of endothelin-1 levels (5.81 vs. 5.26 fmol/ml, p = 0.01). The authors proved also an unequivocal declining trend of other cytoadhesion molecules and vWf after ACEI treatment, the changes however were not statistically significant. From the investigation it may be concluded that also patients with uncomplicated essential hypertension without other cardiovascular risk factors or clinical manifestations of atherosclerosis have significantly elevated plasma levels of ICAM-1, vWf and endothelin-1. Higher concentrations of these factors suggest endothelial dysfunction already in mild forms of essential hypertension without further risk factors or cardiovascular complications. A significant drop of endothelin-1 and declining trend of the other investigated indicators suggest that ACEI treatment can favourably influence endothelial dysfunction in hypertensive patients also independently on reduction of the BP.     

Soluble CD40 ligand and atrial fibrillation: relationship to platelet activation, and endothelial damage/dysfunction

Increased plasma soluble CD40L (sCD40L) is present in many cardiovascular diseases and predicts poor outcome, but levels in atrial fibrillation (AF) are unknown. Although the platelet is frequently cited as the source of sCD40L, this view is not universal. We hypothesised (a) raised sCD40L in non-rheumatic AF, and (b) that sCD40L correlates with platelet, but not endothelial, markers, thus suggesting a platelet origin. Plasma sCD40L, platelet marker soluble P-selectin and endothelial markers von Willebrand factor (vWf) and soluble E-selectin were measured by ELISA in 54 AF patients free of diabetes or major cardiovascular disease, and in 28 age/sex matched controls. Median (inter-quartile range) sCD40L in AF was 0.82 (0-4.8) ng/mL compared to 0.21 (0-5.5 ng/mL) in controls (p=0.0397). vWf and soluble P-selectin (p<0.005), but not soluble E-selectin, were raised in AF, but none of the indices inter-correlated significantly. We find that sCD40L is marginally raised in AF but the stimulus for this is unclear. The lack of clear correlation with relevant plasma markers suggests that the source is unlikely to be the endothelium or platelet alone.     

Levels of plasma total adrenomedullin are related with two acute phase inflammatory reactants (fibrinogen and sialic acid) but not with markers of endothelial dysfunction in Type 1 diabetes Adrenomedullin and vascular risk factors in Type 1 DM

Adrenomedullin (AM), an ubiquitous regulatory peptide with different actions, is known to be elevated in different clinical situations, including diabetes mellitus (DM), but its potential role in the pathogenesis of diabetic vascular complications is not clear. In the present study, we examined plasma total AM levels, and their association with different markers of endothelial dysfunction and with other established risk factors for cardiovascular diseases, in patients with Type 1 DM. We studied a total of 155 patients, 117 patients without any kind of vascular complications, 24 patients with retinopathy only, and 14 patients with retinopathy and microalbuminuria but normal renal function. None of them had clinical evidence of atherosclerotic disease. Compared with the control group (64 healthy participants), patients had raised fibrinogen, soluble E-selectin ((s)E-selectin), vascular cellular adhesion molecule (VCAM), angiotensin converting enzyme (ACE), and von Willebrand factor (vWf) (P<.001 in all cases), but plasma total AM, endothelin (ET), sialic acid, and homocysteine were not raised. In the diabetic group, AM levels correlated significantly with sialic acid (r=.16; P<.05), but a more significant correlation was found with fibrinogen (r=.30; P<.001). No correlation was found with the other parameters studied. In summary, plasma total AM levels seem to correlate with inflammatory markers but not with endothelial dysfunction markers in Type 1 diabetic patients without atherosclerotic disease.     

Increased circulating endothelial cells in acute heart failure: comparison with von Willebrand factor and soluble E-selectin

BACKGROUND: Circulating endothelial cells (CECs) in the peripheral blood, probably representing the most direct evidence of endothelial cell damage, are increased in myocardial infarction, unstable angina and critical limb ischaemia. As chronic heart failure is also associated with endothelial abnormalities, we hypothesised that CECs are raised in acute heart failure and that they would correlate with plasma indices of endothelial perturbation, that is, von Willebrand factor (vWf) and soluble E-selectin. METHODS: We studied 30 patients with acute heart failure (venesected within 24 h of emergency hospital admission), 30 patients with chronic stable heart failure (venesected as out-patients, all patients in sinus rhythm with ejection fraction < or = 40%) and 20 healthy controls. CECs were quantified using epifluorescence microscopy after CD146-immunomagnetic separation and phenotyped by streptavidin/biotin immunocytochemistry. Citrated plasma was analysed for soluble E-selectin and vWf by ELISA. RESULTS: Levels of CECs, vWf and soluble E-selectin were significantly higher (all p<0.01) in patients with heart failure compared to controls, with no significant differences between acute and chronic heart failure. CECs correlated with plasma vWf (p<0.0001) and soluble E-selectin (p = 0.022) but not ejection fraction or NYHA class. In multiple regression analysis, heart failure was the only independent predictor of raised CECs (p<0.0001). Immunoperoxidase-defined surface expression of CD34, CD45 and CD36 by CECs was <2%, 0% and 8%, respectively. CONCLUSION: CECs, a possibly heterologous population, may be used as a novel measure of endothelial damage in acute heart failure and may have implications for the thrombotic risk associated with acute and chronic heart failure and prognosis in this condition.     

Angiopoietin-1 and angiopoietin-2 in diabetes mellitus: relationship to VEGF, glycaemic control, endothelial damage/dysfunction and atherosclerosis

BACKGROUND: microvascular complications in diabetes identify those at risk of cardiovascular disease (CVD), suggesting a link between abnormal neovascularisation and CVD. This may be related to high plasma vascular endothelial growth factor (VEGF). We hypothesised increased angiopoietins (Ang)-1 and -2 in patients with diabetes that are related to VEGF, medium-term glycaemic control, endothelial damage/dysfunction and atherosclerosis. METHODS AND PATIENTS: we measured plasma Ang-1 and Ang-2 alongside VEGF (all by ELISA) in 96 patients with type-2 diabetes mellitus (41 with and 56 without overt CVD) who were compared to 35 age- and sex-comparable healthy controls. Common carotid intima-media thickness (CC-IMT) was used to assess carotid atherosclerosis, plasma von Willebrand factor (vWf) and urine albumin:creatinine ratio (UACr) to quantify and endothelial damage/dysfunction, and HbA1c to mark medium-term hypergylcaemia. RESULTS: Ang-2 (but not Ang-1) was higher in patients with diabetes compared to controls (p<0.01), with no significant difference between patients with and without CVD. As expected, CC-IMT, UACr, HbA1c, vWf, and VEGF were also abnormal in the patients. Within the patient group alone, and in the entire cohort, VEGF and Ang-2 correlated strongly (both p<0.001) and with several other markers. However, in multivariate analysis, the only significant relationship that remained after adjustments was between VEGF and HbA1c (p<0.001). CONCLUSIONS: Angiogenic growth factor Ang-2, like VEGF, is raised in diabetes regardless of vascular disease. Both growth factors correlated with HbA1c and with each other, not with endothelial injury or atherosclerosis, but after multiple adjustment, only that between HbA1c and VEGF significant remained. VEGF is likely to have a more prominent role in diabetes than Ang-2.     

A comparison of flow-mediated dilatation and von Willebrand factor as markers of endothelial cell function in health and in hypertension: relationship to cardiovascular risk and effects of treatment: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial.

Loss of adequate endothelial cell function (associated with various cardiovascular syndromes such as hypertension) is most widely quantified by assessing flow-mediated dilatation (FMD) or measuring plasma markers such as von Willebrand factor (vWF). However, the relationship between these two methods is unclear, as is their relationship to 10-year cardiovascular risk (defined by the Framingham equation) and their response to intensive cardiovascular risk factor management. We tested the hypothesis that there is an inverse relationship between vWF and FMD by measuring both in 132 subjects, of whom 89 were hypertensive (mean blood pressure, 167/91 mmHg) and 43 were healthy normotensive (mean blood pressure, 133/80 mmHg). High-resolution ultrasound assessed endothelium-dependent brachial artery FMD following reactive hyperaemia after occlusion. Plasma vWF was defined by enzyme-linked immunosorbent assay. These measurements were repeated in the patients after 6 months of intensive cardiovascular risk factor management. vWF and FMD correlated significantly (r = -0.517, P < 0.001), and both correlated with 10-year cardiovascular risk using the Framingham equation (vWF, r = 0.48, P < 0.001; FMD, r = -0.624, P < 0.001). Following 6 months intensive cardiovascular risk factor management, plasma vWF was significantly reduced whereas FMD significantly increased (both P < 0.002). We conclude that two fundamentally different methods for assessing endothelial function correlate well with each other, as well as with 10-year cardiovascular risk. Six months of intensive risk factor management is beneficial to the endothelium, as defined by improved vWF and FMD. These methods might therefore be useful indices to identify patients at risk of future cardiovascular events, and may also assist in the understanding of early developments in the pathogenesis of vascular risk in hypertension.     

Relationship of homocysteine to markers of platelet and endothelial activation in "high risk" hypertensives: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial

OBJECTIVE: To examine the relationship between plasma homocysteine (HCY) and rheological, endothelial and platelet markers in "high risk" hypertensive patients. DESIGN: Cross-sectional study. SUBJECTS AND METHODS: A total of 165 consecutive hypertensive patients (136 male; mean age 63 years (S.D. 8)) at high risk of cardiovascular disease who screened for inclusion in the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) were studied along with 38 population normotensive healthy controls. We measured levels of plasma homocysteine [high pressure liquid chromatography (HPLC)], soluble P-selectin, a marker of platelet function, von Willebrand factor (vWF), an index of endothelial damage/dysfunction [both by ELISA] and fibrinogen (CLAUSS). The Framingham cardiovascular and cerebrovascular risk scores were calculated. RESULTS: Hypertensives had significantly higher blood pressure (BP) [165/90(16/10) vs. 138/82(12/8) mm Hg, p<0.0001], sP-sel [54(44-67) vs. 45(35-57) ng/ml, p=0.002], vWF [133(34) vs. 110(28) IU/dl, p<0.0001], and fibrinogen [2.98(2.52-3.47) vs. 2.43(2.20-2.83)g/l, p=<0.0001]. Homocysteine were lower in our hypertensives compared with controls [8.7(6.9-11.2) vs. 10.5(8.5-13.1) micromol/l, p=0.005], but there were significant correlations between homocysteine levels and both calculated 10-year coronary heart disease risk (Spearman r=0.197, p=0.026) and stroke risk (r=0.210, p=0.018), using the Framingham equation. There was a positive correlation between plasma homocysteine and soluble P-selectin (r=0.180, p=0.025), which persisted in multiple linear regression analysis. There was no significant relationship between homocysteine and HCT, PV, or the endothelial marker, vWF. CONCLUSION: Hypertensives demonstrate abnormalities of endothelial, platelet and rheological function. Homocysteine is related to both 10-year coronary heart disease risk and stroke risk, and is significantly correlated with soluble P-selectin, a marker of platelet activation, in hypertensives but only weakly or not at all to other thrombotic markers. Increased platelet activation as reflected by soluble P-selectin may be one mechanism by which hyperhomocysteinaemia confers an increased thrombotic risk in hypertension.     

Humoral markers of inflammation and endothelial dysfunction in relation to adiposity and in vivo insulin action in Pima Indians

Several studies have shown that humoral markers of inflammation and endothelial dysfunction are predictive of macrovascular events, and correlated with indirect measures of adiposity and insulin action, thus providing a possible link between obesity, insulin resistance and atherosclerosis. We examined the relationship between humoral markers of inflammation and endothelial dysfunction and direct measures of adiposity and insulin action in Pima Indians, a population with a very high prevalence of obesity and insulin resistance, but a relatively low propensity for atherosclerotic disease. Fasting plasma concentrations of the inflammatory markers C-reactive protein (CRP), secretory phospholipase A2 (sPLA2) and soluble intercellular adhesion molecule-1 (sICAM-1) and of the endothelial markers E-selectin and von Willebrand factor (vWF) were measured in 32 non-diabetic Pima Indians (18 M/14 F, age 27+/-1 years) in whom percent body fat and insulin-stimulated glucose disposal (M) were assessed by DEXA and a hyperinsulinemic clamp, respectively. CRP, sPLA2, and sICAM-1 were all positively correlated with percent body fat (r=0.71, 0.57, and 0.51, all P<0.01). E-selectin and vWF were not correlated with percent body fat, but were negatively correlated with M (r= -0.65 and -0.46, both P<0.001) and positively correlated with CRP (r=0.46, and 0.33, both P<0.05). These findings indicate that humoral markers of inflammation increase with increasing adiposity in Pima Indians whereas humoral markers of endothelial dysfunction increase primarily in proportion to the degree of insulin resistance and inflammation. Thus, obesity and insulin resistance appear to be associated with low-grade inflammation and endothelial dysfunction, respectively, even in an obesity- and diabetes-prone population with relatively low propensity for atherosclerosis.     

Prognostic value of the Framingham cardiovascular risk equation and the UKPDS risk engine for coronary heart disease in newly diagnosed Type 2 diabetes: results from a United Kingdom study.

AIMS: To determine the prognostic value of the Framingham equation and the United Kingdom Prospective Diabetes Study (UKPDS) risk engine in patients with newly diagnosed Type 2 diabetes. METHODS: A community-based cohort (n=428; aged 30-74 years) free of clinically evident CVD and newly diagnosed with Type 2 diabetes were studied over a median 4.2 (sd+/-0.62) years. Predicted (using baseline variables at diagnosis) and observed proportions of primary CVD and CHD events were compared using the Framingham equations and the UKPDS risk engine (only CHD events). The discrimination (c-statistic) and calibration (HLchi2) of the risk equations were calculated. The sensitivity and specificity of the Framingham equation at a 15%, 10-year CHD risk threshold (NICE guidelines) was compared with that of the ADA lipid threshold (LDLc>or=2.6 mmol/l or triglycerides>or=4.5 mmol/l). RESULTS: The Framingham equations underestimated the overall number of cardiovascular events by 33% and coronary events by 32% and showed modest discrimination and poor calibration for CVD [c=0.673; HLchi2=32.8 (P<0.001)] and CHD risk [c=0.657; HLchi2=19.8 (P=0.011)]. Although the overall underestimate was lower and non-significant with the UKPDS risk engine for CHD (13%), its performance in terms of discrimination and calibration were similar [c=0.670; HLchi2=17.1 (P=0.029)]. The 15%, 10-year CHD risk threshold with both the Framingham and UKPDS risk engines had similar sensitivity for primary CVD as the lipid level threshold [85.7 and 89.8% vs. 93.9% (P=0.21 and 0.34)] and both had greater specificity [33.0 and 30.3% vs. 12.1% (P<0.001 and P<0.001)]. CONCLUSIONS: In people with newly diagnosed Type 2 diabetes, both the Framingham equation and UKPDS risk engine are moderately effective at identifying those at high-risk (discrimination) and are poor at quantifying risk (calibration). Nonetheless, at a population level, a 15% 10-year CHD risk threshold using either risk calculator has similar sensitivity as an approach based on a single lipid risk factor level and may have benefits in terms of cost-effectiveness given the improved specificity.     

Plasma levels of tissue factor and soluble E-selectin in sickle cell disease: relationship to genotype and to inflammation.

BACKGROUND: Microvascular occlusion, the pathophysiological hallmark of sickle cell disease (SCD), is a complex multifactorial process with alterations in coagulation, endothelial function and inflammation. However, relationships between these process in the two most common genotypes, HbSS and HbSC, are unknown. We hypothesized differences in the hypercoagulable state [as assessed by tissue factor (TF), fibrinogen and D-dimer], endothelial function [markers soluble E-selectin (sE-sel) and von Willebrand factor (vWf)], and inflammation [markers interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hsCRP)] in these two SCD genotypes. Citrated plasma TF, sE-sel, vWf, fibrinogen and fibrin D-dimer, and serum IL-6 and hsCRP (enzyme-linked immunosorbent assay/Clauss) were measured in 64 patients with SCD (27 with HbSS disease) and 42 AA subjects matched for age and ethnic origin. TF (P = 0.0014), sE-sel (P = 0.001) and, as expected, vWf, D-dimer, and hsCRP (all P < or = 0.01), but not fibrinogen or IL-6, were raised in the SCD patients compared with the AA subjects. However, only vWf and, as expected, D-dimer (all P < or = 0.01) were higher in HbSS disease than in HbSC disease. Raised plasma TF and sE-sel in SCD compared with HbAA subjects may contribute to the increased risk of thrombotic disease in this group. Raised vWf in HbSS compared with HbSC may be important in determining pathophysiology in these two genotypes. Positive correlations between IL-6 and TF in both HbSC and HbSS disease leads us to speculate that inflammation may be important in coagulation activation in these patients, or vice versa. However, lack of correlation of sE-sel with inflammatory markers implies that other mechanisms are responsible for increased levels of this marker of endothelial activation.     

Endothelial function and aminothiol biomarkers of oxidative stress in healthy adults

Endothelial dysfunction is known to precede the development of atherosclerosis and results primarily from increased oxidative degradation of NO. We hypothesized that assessment of oxidative stress in the bloodstream will reliably predict endothelial function in healthy adults. A total of 124 healthy nonsmokers had endothelial function assessed using ultrasound measurement of brachial artery flow-mediated vasodilation. Plasma oxidative stress was estimated by measuring the levels of the reduced and oxidized forms of thiols, including glutathione (reduced glutathione and oxidized glutathione) and cysteine (cysteine and cystine), respectively, and the mixed disulfide. Among the traditional risk factors, there were significant and independent correlations between flow-mediated vasodilation and high-density lipoprotein level, body mass index, gender, and the Framingham risk score. Among the thiol markers, plasma cystine (r=-0.23; P=0.009) and the mixed disulfide (r=-0.23; P=0.01) levels correlated with endothelium-dependent but not endothelium-independent vasodilation, even after adjusting for the Framingham risk score and high-sensitivity C-reactive protein level. A higher level of oxidized metabolites was associated with worse endothelial function. In conclusion, the oxidative stress markers, cystine, and the mixed disulfide are independent predictors of endothelial function. These markers, in combination with the Framingham risk score, may help in the early identification of asymptomatic subjects with endothelial dysfunction who are at potentially increased risk for future atherosclerotic disease progression.     

Circulating intercellular cell adhesion molecule-1, endothelin-1 and von Willebrand factor-markers of endothelial dysfunction in uncomplicated essential hypertension: the effect of treatment with ACE inhibitors

The aim of the study was to examine whether the circulating cell adhesion molecules, von Willebrand factor (vWf) and endothelin-1, are elevated in patients with essential hypertension with no other risk factors for atherosclerosis and thus may serve as a markers of endothelial dysfunction in uncomplicated hypertension. Furthermore, the effect of treatment with the ACE inhibitor, quinapril, on levels of endothelial dysfunction markers were studied. The levels of adhesion molecules (intercellular cell adhesion molecule-1 [ICAM-1], E-selectin, P-selectin), von Willebrand factor (vWf) and endothelin-1 were measured in patients with hypertension without any other risk factors of atherosclerosis before and after treatment with quinapril (n = 22) and in normotensive controls (n = 22). Compared with normotensive subjects, the hypertensive patients had significantly higher levels of ICAM-1 (238 vs 208 ng/ml, P = 0.02), vWf (119 vs 105 IU/dl, P < 0.05) and endothelin-1 (5.76 vs 5.14 fmol/ml, P < 0.05). Three-month treatment of hypertensive patients with quinapril led to a significant decrease in the levels of endothelin-1 (5.76 vs 5.28 fmol/ml, P < 0.01). We did not observe significant changes in the levels of adhesion molecules and vWf after ACE inhibitor treatment, although a trend toward a decrease was apparent with all these parameters. Patients with uncomplicated hypertension with no other risk factors of atherosclerosis had significantly elevated levels of ICAM-1, vWf, and endothelin-1. Our data suggest that these factors may serve as markers of endothelial damage even in uncomplicated hypertension. In hypertensive patients, treatment with the ACE inhibitor quinapril resulted in a significant decrease in endothelin-1 levels. These findings indicate a beneficial effect of ACE inhibitors on endothelial dysfunction in hypertensive patients.     

Endothelial activation, dysfunction, and damage in congestive heart failure and the relation to brain natriuretic peptide and outcomes

Congestive heart failure (CHF) is associated with marked endothelial dysfunction. We hypothesized that acute and chronic CHF may manifest different degrees of endothelial damage/dysfunction and activation, as reflected by different plasma endothelial markers, such as von Willebrand factor (vWF) and soluble thrombomodulin (both are indexes of endothelial damage/dysfunction) and soluble E-selectin (an index of endothelial activation). Second, we hypothesized a relation between endothelial markers and B-type natriuretic peptide (BNP, an index of cardiac function) in acute and chronic CHF that could be linked to prognosis. To test this hypothesis, we studied 35 patients with acute CHF, 40 patients with chronic CHF, and 32 healthy controls. The patients with CHF were followed up for the combined outcomes of cardiovascular death, nonfatal myocardial infarction, stroke, thromboembolism, and recurrent admissions to the hospital. vWF (p = 0.001), soluble thrombomodulin, E-selectin, and BNP (all p <0.0001) were higher in patients with acute and chronic CHF compared with controls. When the 2 CHF groups were compared, no significant differences were found in vWF or E-selectin (p = NS), but soluble thrombomodulin was significantly elevated in acute CHF (Tukey's post hoc test, p <0.05). Only high vWF was associated with a poorer outcome (log-rank test, p = 0.0188). None of the endothelial indexes correlated with plasma BNP. After a median follow-up of 18 months, only high (median or higher) vWF levels were predictive of adverse outcomes in the patients with CHF (log-rank statistic = 5.52, degree of freedom 1, p = 0.0188). In conclusion, despite similar ejection fractions, patients with acute and chronic CHF have different degrees of endothelial damage/dysfunction and activation, which may be related to differences in pathophysiology. High levels of vWF were associated with a worse short-term outcome. These endothelial markers were unrelated to plasma BNP levels and may imply a different release mechanism.     

Physical activity in relation to indices of endothelial function and angiogenesis factors in hypertension: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT)

BACKGROUND: Hypertension is an important risk factor for cardiovascular disease. The latest guidelines recommend regular physical exercise as initial step or adjunct in the treatment of hypertension. We investigated the association between physical activity and the degree of hypertension, as well as the relation to indices of endothelial damage/dysfunction and angiogenesis. METHODS: We studied 234 patients with hypertension (198 males; mean age 64 years; mean blood pressure 166/90 mmHg), who were compared with 60 age and sex-matched healthy normotensive controls. We assessed the patient's physical activity using the validated Baecke physical activity questionnaire and measured flow-mediated dilatation (FMD) of the brachial artery and von Willebrand factor (vWf) as indices of endothelial damage/dysfunction, whilst angiogenesis was assessed by measurement of plasma vascular endothelial growth factor (VEGF) and its soluble receptor (sFlt-1) both by ELISA. RESULTS: When hypertensive patients were compared with the controls, there was no statistically significant difference in total physical activity score using the Baecke questionnaire although plasma VEGF and vWf levels were higher, but sFlt-1 levels and FMD lower (all P < 0.001). Patients with high physical activity were younger, and had lower mean diastolic blood pressure and 10-year Framingham stroke risk, when compared with those with low physical activity; but indices of endothelial damage/dysfunction and angiogenesis were not significantly different. CONCLUSION: Physical activity scores in hypertensive patients are not significantly different from healthy normotensive controls, and there appears to be no relation to the abnormal processes of endothelial damage/dysfunction and angiogenesis seen in hypertensives.     

Prognostic value of increased soluble thrombomodulin and increased soluble E-selectin in ischaemic heart disease

Abstract: Endothelial cell dysfunction is likely to be important in the pathophysiology of ischaemic heart disease and increased levels of endothelial cell markers soluble E-selectin and soluble thrombomodulin may reflect this damage. To determine whether increased levels of these markers were predictive of disease progression, we obtained plasma from 54 patients who had survived a myocardial infarction. Soluble E-selectin and soluble thombomodulin were measured by ELISA. After 49 months, 24 patients had suffered an additional cardiovascular event such as a second myocardial infarction or requirement for arterial surgery. Soluble E-selectin was 60±30 ng/mL in patients who suffered an end-point and was 54±23 ng/mL in those without an end-point (p = 0.43). Soluble thrombomodulin was 65±24 ng/mL in patients who suffered an end-point and was 49±19 ng/mL in patients who were free of an end-point (p = 0.009). The major risk factors for atherosclerosis (hypercholesterolaemia, hypertension, smoking) or peak creatinine kinase levels were unable to predict the development of an end-point. Using life tables, soluble thrombomodulin had a significant effect on survival free of an end-point (p = 0.011). We conclude that the measurement of soluble E-selectin is of limited value in epidemiological studies, and that raised soluble thrombomodulin is a new marker for the progression of atherosclerosis in patients with ischaemic heart disease.