Relation of thrombogenesis in systemic hypertension to angiogenesis and endothelial damage/dysfunction (a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial [ASCOT])

Differential effect of celecoxib on tissue factor expression in human endothelial and vascular smooth muscle cells

In endothelial cells (EC), celecoxib inhibits expression of tissue factor (TF), a key protein for initiation and propagation of thrombus formation. The current study was designed to examine the effect of celecoxib on TF expression and activity in VSMC. In contrast to EC, celecoxib increased TNF-alpha-induced TF expression and surface activity in VSMC by 33% and 20%, respectively, as compared to TNF-alpha alone, while rofecoxib or NS-398 had no effect. Celecoxib increased p38 MAP kinase (p38), p44/42 MAP kinase (ERK), and p70S6 kinase (p70S6K) phosphorylation while leaving JNK activation unaffected. Simultaneous inhibition of p38 and ERK reduced TNF-alpha-induced TF expression by 59%, while inhibition of JNK with SP600125 did not affect TF expression. Thus, in contrast to endothelial cells, celecoxib does not inhibit TF expression in VSMC, but instead enhances it. As neither rofecoxib nor NS-398 affected TF expression, this effect does not seem to be related to COX-2 inhibition but rather appears to be mediated by an increase in p38, ERK, and p70S6K activation. The observation that the inhibiting effect of celecoxib on endothelial TF expression does not extend to VSMC may have important implications for patients with cardiovascular disease.

Influence of Atorvastatin Treatment on l -Arginine Cerebrovascular Reactivity and Flow-Mediated Dilatation in Patients With Lacunar Infarctions

Background and Purpose— In our study we hypothesized that statins improve endothelial function in patients with lacunar infarctions (LI). Cerebral and systemic endothelial function was determined before and after 3-months treatment with atorvastatin.

Methods— Cerebral endothelial function was determined by l -arginine reactivity and systemic endothelial function by flow-mediated dilatation (FMD) in patients with LI (18 patients, aged 61.1±7.6 years), 20 age- and gender-matched patients with similar risk factors (SR) and 19 age- and gender-matched healthy controls. The mean arterial velocity (v m ) in both middle cerebral arteries was measured by transcranial Doppler sonography before, during and after a 30-minute intravenous infusion of l -arginine. FMD of the brachial artery after hyperaemia was determined. The measurements were repeated after 3-months treatment with 40 mg of atorvastatin per day.

Results— l -arginine reactivity was decreased in LI patients (13.1±8.4%) and in patients with SR compared with healthy controls ( P ≤0.01). FMD was more impaired in patients with LI (0.06±4.9%) compared with patients with SR and healthy controls ( P ≤0.01). After atorvastatin treatment, l -arginine reactivity and FMD improved in both patients with LI (17.1±7.6%; 7.0±5.7%) and patients with SR ( P ≤0.01). Previously mildly increased cholesterol values normalized.

Conclusion— The decreased l -arginine reactivity and FMD improve after atorvastatin treatment in both patients with LI and patients with SR.

Tissue factor expression and activity are not increased in peripheral monocytes isolated from uncomplicated hypertensive patients

BACKGROUND

Systemic hypertension is one of the main risk factors for atherothrombosis. Tissue factor (TF) is found in the adventitia of blood vessels and in the lipid core of atherosclerotic plaques, and is specifically expressed on monocyte or macrophage cell membrane surfaces. TF plays a pivotal role in blood clotting physiology and is involved in pro-inflammatory action and atherosclerotic plaque destabilization.

OBJECTIVE

In this study we investigated whether there is any relationship between TF messenger RNA expression and activity in blood monocytes isolated from hypertensive patients with clinical signs of atherosclerosis, uncomplicated hypertensive individuals and normotensive control subjects.

METHODS

Eighty subjects (41 men and 39 women, mean age 41 +/- 12 years) with untreated essential hypertension and 41 control subjects matched for sex and age were enrolled in the study. Patients were classified according to whether they had a normal (</= 1 mm, 41 patients) or abnormal (> 1 mm, 39 patients) intima-media thickness (IMT).

RESULTS

TF mRNA expression and activity in hypertensive individuals with no carotid atherosclerosis were no different from control subjects in unstimulated and stimulated monocytes. Abnormal IMT patients showed a higher TF mRNA expression compared with normal IMT hypertensive subjects (P < 0.001).

CONCLUSIONS

We demonstrated that TF mRNA and activity levels in monocytes obtained from uncomplicated hypertensive individuals are comparable with those of normotensive subjects, whereas atherosclerotic hypertensive patients showed increased levels of these parameters.

Abnormal soluble CD40 ligand and C-reactive protein concentrations in hypertension: relationship to indices of angiogenesis

BACKGROUND

Abnormal inflammation, platelets and angiogenesis are involved in the pathophysiology of cardiovascular disease (CVD).

OBJECTIVE

To test the hypothesis that concentrations of high sensitive C-reactive protein (CRP, an index of inflammation) and soluble CD40 ligand (sCD40L, an index of platelet activation) would be abnormal in hypertension, and in turn, be related to plasma indices of angiogenesis, the angiopoietins-1 and -2, and vascular endothelial growth factor (VEGF), in addition to the presence or absence of CVD.

METHODS

Using a cross-sectional approach, we measured plasma concentrations of CRP, sCD40L, VEGF, and angiopoietins-1 and -2 in 147 patients with hypertension (85 with a history of CVD event/s, 62 CVD event-free) and 68 age- and sex-matched healthy controls.

RESULTS

Concentrations of sCD40L (P = 0.039), CRP (P < 0.001), angiopoietin-1 (P < 0.001), angiopoietin-2 (P = 0.003) and VEGF (P < 0.001) were all greater amongst hypertensive patients than in controls. There were no significant differences in sCD40L and VEGF concentrations between hypertensive individuals with and without CVD events, but CRP and angiopoietin-1 concentrations were significantly greater amongst those with CVD events. On multiple regression analysis, sCD40L was associated with angiopoietin-2 (P = 0.01) and VEGF (P = 0.007) in hypertensive individuals, but no such associations were found within the healthy control group.

CONCLUSION

In patients with hypertension, sCD40L was associated with increased circulating markers of abnormal angiogenesis (angiopoietin-2, VEGF). The interaction between sCD40L and angiogenesis may contribute to the pathophysiology of CVD in hypertension.

Tissue Factor in Cardiovascular Diseases

Tissue factor (TF), formerly known as thromboplastin, is the key initiator of the coagulation cascade; it binds factor VIIa resulting in activation of factor IX and factor X, ultimately leading to fibrin formation. TF expression and activity can be induced in endothelial cells, vascular smooth muscle cells, and monocytes by various stimuli such as cytokines, growth factors, and biogenic amines. These mediators act through diverse signal transduction mechanisms including MAP kinases, PI3-kinase, and protein kinase C. Cellular TF is present in three pools as surface, encrypted, and intracellular protein. TF can also be detected in the bloodstream, referred to as circulating or blood-borne TF. Elevated levels of TF are observed in patients with cardiovascular risk factors such as hypertension, diabetes, dyslipidemia, and smoking as well as in those with acute coronary syndromes. TF may indeed be involved in the pathogenesis of atherosclerosis by promoting thrombus formation; in addition, it can induce migration and proliferation of vascular smooth muscle cells. As a consequence, therapeutic strategies have been developed to specifically interfere with the action of TF such as antibodies against TF, site-inactivated factor VIIa, or recombinant TF pathway inhibitor. Inhibition of TF action appears to be an attractive target for the treatment of cardiovascular diseases.

Factor XII (Hageman factor) is a missing link between stress and hypercoagulability and plays an important role in the pathophysiology of ischemic stroke

A new hypothesis is presented on the function of factor XII, which is postulated to be a "missing link" between acute stress and transient hypercoagulability. The implications of this idea are developed to show how chronic stress, which involves activation of hypertension and migraine as well as hypercoagulability, can cause of cerebrovascular disease. "Acute stress" is defined as "the normal short-term physiological response to the perception of major threats or demands". "Chronic stress" is "the abnormal ongoing physiological response to the continuing perception of unresolvable major threats or demands". The factor XII hypothesis is as follows: Acute stress includes release of epinephrine by the adrenal medulla. Epinephrine activates platelets by binding to alpha-2A adrenergic receptors. Activated platelets convert pre-bound factor XII to its active form, which then initiates the intrinsic coagulation cascade. This can be called the "activated platelet initiation pathway" for coagulation. Neither tissue factor nor pre-formed thrombin is required. Thrombosis proceeds to completion, but only a minute amount of thrombin is formed, and the process normally stops at this point. In people who lapse into a state of chronic stress, essential hypertension, which is also a manifestation of stress, synergizes with hypercoagulability: there is both a baseline rise in blood pressure and systemic platelet activation as well as superimposed labile rises of both. Upregulation of these two stress parameters is atherogenic: epinephrine-activated platelets stimulating thrombin formation interact with endothelial cells activated by angiotensin II to cause, first, smooth muscle cell proliferation, which is a histological hallmark of atherosclerosis, and, lastly, a symptomatic thrombotic occlusion-the stroke. The migraine symptoms which often accompany this process are a marker of chronic stress and ongoing pathophysiologic damage. Therapeutic predictions are made regarding novel ways of blocking stress-induced hypercoagulability and hypertension. Hypercoagulability could be targeted by monoclonal antibodies directed against the platelet-specific alpha-2 adrenergic receptor or the (putative) platelet receptor for Factor XII; hypertension could be treated with monoclonal antibodies directed against the beta-adrenergic receptor in the juxtaglomerular apparatus or by surgical denervation of the kidneys, either of which would decrease the renin release which helps drive the hypertension.

Rheumatoid disease and ischaemic heart disease: Insights from pathophysiology and vascular biology

Rheumatoid disease (RD) is a multisystem inflammatory disorder, which is associated with an increased cardiovascular mortality, thought to be due to ischaemic heart disease (IHD). The precise mechanisms causing increased IHD in RD are unclear. However, there is increasing recognition that atherosclerosis is another chronic inflammatory condition, which shares several pathophysiological features with RD. For example, endothelial damage/dysfunction, platelet activation, hypercoagulability and angiogenesis are well-recognised in both disease processes. Furthermore, RD may influence traditional risk factors such as dyslipidaemia. Although the exact reasons for the increased ischaemic burden are unclear, physicians should place a high priority upon reducing cardiovascular risk in sufferers of RD. This review summarises factors that might contribute to the pathogenesis of IHD in RD. Discussion will focus upon features shared by atherosclerotic and rheumatoid processes, as well as possible interactions between RD and conventional IHD risk factors.

Abnormal angiopoietins 1&2, angiopoietin receptor Tie-2 and vascular endothelial growth factor levels in hypertension: relationship to target organ damage [a sub-study of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT)]

BACKGROUND

The increased risk of target organ damage (TOD) in hypertension may be related to a prothrombotic or hypercoagulable state, with abnormalities in platelet activation. Altered angiogenesis, possibly related to increased plasma vascular endothelial growth factor (VEGF) is also a feature of hypertension. We hypothesized a link between altered angiogenesis and TOD in hypertension. Accordingly, the angiogenic growth factors VEGF, angiopoietin 1 and 2 (Ang 1 & 2) and soluble angiopoietin receptor Tie-2 in plasma and in platelets were assessed in terms of the presence or absence of hypertensive TOD.

METHODS

We studied 199 patients (75% men; mean age 68 years) with hypertension. Of these, 125 had evidence of hypertensive TOD (stroke, previous myocardial infarction, angina, left ventricular hypertrophy and mild renal failure). Patients were compared with 74 healthy normotensive controls (69% men; mean age 68 years). Plasma VEGF, Ang 1 & 2 and Tie-2, and total platelet levels of VEGF and Ang-1 (obtained by lysing a known number of platelets with 0.5% Tween) were measured by an enzyme-linked immunosorbent assay.

RESULTS

Hypertensive patients had higher levels of plasma VEGF, Ang-1, Ang-2, Tie-2 and platelet VEGF (all P<or=0.01), but not platelet Ang-1, when compared with normotensive controls. Patients with TOD had higher levels of platelet VEGF and Ang-1 (both P<0.001), and plasma Ang-1 (P<0.001). Amongst the hypertensives, plasma levels of VEGF correlated significantly with Ang-1, Ang-2, Tie-2 and platelet VEGF, whilst platelet VEGF correlated strongly with plasma levels of VEGF and Ang-1 (all P<0.05).

CONCLUSION

Patients with hypertension have evidence of changes in plasma angiogenic growth factors that correlate with the platelet levels of these molecules. Platelets may be involved in the abnormal angiogenesis seen in hypertension.

Histamine Induces Tissue Factor Expression

Background— Histamine can induce coronary vasospasm, leading to variant angina and acute myocardial infarction. However, the role of histamine in thrombus formation is ill defined. Hence, this study investigates whether histamine induces tissue factor (TF) expression in vascular cells.

Methods and Results— Histamine (10 −8 to 10 −5 mol/L) induced TF expression in a concentration-dependent manner in human aortic endothelial and vascular smooth muscle cells, whereas TF pathway inhibitor expression remained unaffected. RT-PCR and Northern blotting revealed that histamine stimulated TF mRNA transcription, peaking at 1 hour. Protein expression increased 18-fold ( P <0.02) with a maximum at 5 hours, which was paralleled by a 4-fold augmentation in surface activity ( P <0.01). These effects were completely prevented by pretreatment with the H 1 receptor antagonists mepyramine ( P <0.0001), chlorpheniramine, and diphenhydramine but not the H 2 receptor antagonist cimetidine ( P =NS). Histamine induced a time-dependent, H 1 receptor–mediated activation of p38 MAP kinase (p38), p44/42 MAP kinase (ERK), and c-jun terminal NH 2 kinase (JNK). Blocking of p38, ERK, or JNK with SB203580 ( P <0.0001), PD98059 ( P <0.0001), or SP600125 ( P <0.0001), respectively, impaired histamine-induced TF expression in a concentration-dependent manner. In contrast, histamine-stimulated TF expression was increased by phosphatidylinositol 3-kinase inhibition with LY294002 or wortmannin, whereas it was not affected by Rho-kinase inhibition with Y-27632 or hydroxyfasudil.

Conclusions— Histamine induces expression of TF, but not TF pathway inhibitor, in vascular cells via activation of the H 1 , but not H 2 , receptor. This effect is mediated by the MAP kinases p38, ERK, and JNK. This observation may open novel perspectives in the treatment of variant angina and acute coronary syndromes.

Celecoxib Decreases Endothelial Tissue Factor Expression Through Inhibition of c-Jun Terminal NH 2 Kinase Phosphorylation

Background— Despite potential antiinflammatory properties, the use of selective cyclooxygenase-2 inhibitors (coxibs) in patients with cardiovascular diseases has been questioned because of a possibly increased thrombotic risk. Tissue factor (TF), a key protein for initiation of coagulation, has been implicated in the pathogenesis of atherosclerosis and thrombosis. Hence, we examined the effect of different coxibs on TF expression.

Methods and Results— Celecoxib (10 −5 mol/L), but not rofecoxib (10 −7 to 10 −5 mol/L) or the experimental coxib NS-398 (10 −7 to 10 −5 mol/L), decreased tumor necrosis factor-α–induced TF expression and activity in human aortic endothelial cells. Celecoxib (10 −5 mol/L) reduced activation of c-jun terminal NH 2 kinase (JNK), whereas it did not affect p38 mitogen-activated protein (MAP) kinase or p44/42 MAP kinase; in contrast, JNK activation was not affected by rofecoxib (10 −5 mol/L) or NS-398 (10 −5 mol/L). TF expression was reduced in a concentration-dependent manner by pretreatment with SP600125 (10 −7 to 10 −6 mol/L), a specific inhibitor of JNK, which confirms that JNK regulates tumor necrosis factor-α–induced TF expression.

Conclusions— Celecoxib reduced TF expression and activity in human aortic endothelial cells. Because neither rofecoxib nor the experimental coxib NS-398 affected TF expression, this effect occurs independently of COX-2 inhibition; it is rather mediated through inhibition of JNK phosphorylation. These data indicate a distinct heterogeneity within this class of drugs, which may be clinically relevant, especially for patients with atherosclerotic vascular diseases.

Changes in flow-mediated dilatation, cytokines and carotid arterial stenosis during aggressive atorvastatin treatment in normocholesterolemic patients

BACKGROUND

Aggressive statin therapy to reduce low-density lipoprotein (LDL) cholesterol in patients with normal LDL-cholesterol levels reduces the incidence of future cardiovascular events and enhances atherosclerotic regression in the common carotid artery. We tried to quantify changes in flow-mediated dilatation (FMD), inflammatory cytokines, and the severity of carotid arterial stenosis, after aggressive statin administration to patients with normal LDL-cholesterol levels, and stroke or transient ischemic attack ipsilateral to carotid arterial stenosis.

METHODS

Twenty patients with at least a 50% reduction in the diameter of the carotid artery were studied. Atorvastatin 10 mg daily was prescribed for 4 months. Serial changes in the severity of carotid arterial stenosis, and brachial-artery FMD were evaluated by high-resolution ultrasound. Tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), vascular cell adhesion molecule (VCAM), intracellular adhesion molecule (ICAM), soluble endothelin-1 (ET-1), and high-sensitivity C-reactive protein (hs-CRP), were measured before, and after 2 and 4 months of, atorvastatin treatment.

RESULTS

Atorvastatin significantly decreased plasma levels of total cholesterol and LDL-cholesterol after 1, 2 and 4 months of treatment (p < 0.01). FMD showed significant improvement after only 4 months (10.0% vs 6.8% at baseline; p = 0.019). The overall severity of carotid arterial lesions was not significantly reduced by atorvastatin. Changes in TNF-alpha, IL-1beta, IL-6 and ET-1 showed trends towards a progressive decline after atorvastatin, but none of the cytokines was reduced significantly. FMD did not correlate with the severity of carotid arterial stenosis, lipid profile, or cytokine levels.

CONCLUSION

Atorvastatin effectively reduced plasma concentrations of total cholesterol and LDL-cholesterol, and had beneficial effects on endothelial function, in Chinese patients with carotid arterial stenosis and normal LDL-cholesterol levels.

High circulating vascular endothelial growth factor (VEGF) is related to a better systolic function in diabetic hypertensive patients

BACKGROUND

VEGF seems to have a protective role on cardiac microcirculation, but no data are available on its action on cardiac function and morphology in diabetic patients. We sought to test the hypothesis that circulating VEGF levels could influence the cardiac performance in type 2 diabetic hypertensive patients.

METHODS

We studied 30 patients with type 2 diabetes and hypertension, without severe cardiac, retinal, renal and peripheral vascular damage. Ten non-diabetic hypertensive patients represented the control group. VEGF plasma levels (ELISA) and echocardiographic parameters were evaluated.

RESULTS

Diabetic patients had VEGF plasma levels higher than hypertensive non-diabetic subjects [median 82 (IQR 12-190) vs 50.5 (IQR 28-77) pg/mL, p=0.05]. Simple linear regression analysis showed that VEGF levels are related to relative wall thickness (RWT) and both endocardial and midwall systolic parameters in the diabetic patients. Multiple linear regression analysis showed that RWT and ejection fraction (EF) were the only independent correlates of VEGF (r2=0.274, p=0.03, p=0.05; respectively).

CONCLUSIONS

Our data showed that high VEGF plasma levels are associated to a better systolic function in diabetic hypertensive patients with cardiac remodeling. VEGF may play a role in the improvement of cardiac performance in diabetes.

Angiogenesis: A link to Thrombosis in Athero-thrombotic Disease

New insights to explain the clinical manifestations of atherosclerosis have resulted in a paradigm in which thrombosis is the major cause of acute coronary syndromes, peripheral arterio-vascular disease and stroke. Major efforts have been directed toward developing drugs to reduce thrombin and fibrin formation. Recent studies support a central role for angiogenesis of the atherosclerotic plaque in promoting atherothrombosis. The findings, in the face of efforts to use angiogenic agents to enhance vascular function, underline the challenge in treating atherothrombotic disease.

Platelet adhesion in hypertension: application of a novel assay of platelet adhesion

BACKGROUND

The increased risk of thromboembolism in hypertension may be related to a prothrombotic or hypercoagulable state, with abnormalities in haemostasis and platelet function.

OBJECTIVE

To investigate the role of platelets in the pathogenesis of thrombosis in hypertension, we applied a novel new assay to detect and quantify the degree of platelet adhesion to a defined coagulation molecule.

PATIENTS AND METHODS

Platelet-rich plasma (PRP) and citrated plasma (CP) were obtained from 50 patients with hypertension (25 treated, and 25 untreated) and 30 healthy controls. A suspension of 2 x 10(7) platelets were incubated for one hour in microtitre plates pre-coated with 5mg/mL fibrinogen. The supernatant was carefully aspirated, lysed with 5% tween and stored at -70 degrees C as supernatant platelet lysate (SPL). The wells were carefully washed with saline and bound platelets lysed as before, and stored at -70 degrees C as bound-platelet lysate (BPL). Soluble P-selectin (sP-sel) was determined in CP, SPL and BPL by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Patients with hypertension (both treated and previously untreated) had increased platelet adhesion, as determined by increased lysate sP-sel (P=0.002) in BPL, with no change in SPL (P=0.5) compared to healthy controls. There was no significant difference between treated and previously untreated hypertensives.

CONCLUSION

Platelets from patients with hypertension display increased adhesion to an important coagulation factor (fibrinogen). This may, in part, account for the increased risk of thrombosis seen in these patients.

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.

Preeclampsia and future cardiovascular disease: potential role of altered angiogenesis and insulin resistance

Altered angiogenesis and insulin resistance are associated with preeclampsia and cardiovascular disease (CVD), and women with preeclampsia appear to be at increased risk of future CVD. We hypothesized that these factors are detectable in asymptomatic postpartum women with a history of preeclampsia and may represent pathophysiological mechanisms bridging preeclampsia and future CVD. We measured fasting insulin, glucose, vascular endothelial growth factor, and its circulating inhibitor, soluble fms-like tyrosine kinase (sFlt-1) in 29 normotensive women with a history of preeclampsia and 32 women with prior normotensive pregnancies at 18.0 +/- 9.7 months postpartum. The homeostasis model of insulin resistance (HOMA(IR)) [(insulin [microunits per milliliter] x glucose [millimoles per liter])/22.5] was calculated. Compared with women with normal pregnancies, women with prior preeclampsia had significantly increased levels of sFlt-1 (41.6 +/- 6.7 vs. 30.4 +/- 10.2; P < 0.01) and median HOMA(IR) (2.8 vs. 1.9; P = 0.04). Membership in the upper quartile of either sFlt-1 or HOMA(IR) was associated with prior preeclampsia (odds ratio 5.7; 95% confidence interval 1.7, 20.0; P < 0.01), and all five women in the upper quartiles of both sFlt-1 and HOMA(IR) had a history of preeclampsia. Women with a history of preeclampsia demonstrate altered expression of angiogenesis-related proteins and increased HOMA(IR) more than 1 yr postpartum. These factors may contribute to their risk of future CVD.

Plasma and platelet-derived vascular endothelial growth factor and angiopoietin-1 in hypertension: effects of antihypertensive therapy

BACKGROUND

Platelets carry angiogenic growth factors vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1). Although platelet-derived growth factors are important in the pathogenesis and metastasis of malignancy, their role in the pathogenesis of complications and the response to treatment in hypertension is less known.

OBJECTIVE

To test the hypotheses that there are differences in VEGF and Ang-1 in the plasma and within platelets from patients with hypertension, and that levels change with successful treatment.

METHODS

We recruited 42 previously untreated patients with hypertension (25 male; mean age 53 years) and 30 age- and sex-matched controls. Plasma VEGF, Ang-1 and soluble P-selectin (sPsel, an index of platelet activation), and total platelet [platelet VEGF (pVEGF) and platelet Ang-1 (pAng-1)] were measured by ELISA. The patients were then treated for 6 months with amlodipine-based antihypertensive therapy, achieving a mean blood pressure below 140/80 mmHg.

RESULTS

Patients with hypertension had significantly higher levels of plasma sPsel (P =0.01), VEGF (P < 0.001) and Ang-1 (P = 0.01), as well as pVEGF (P < 0.001) and pAng-1 (P =0.02). The levels of plasma and platelet angiogenic growth factors were significantly reduced after antihypertensive treatment (VEGF, P = 0.01; pVEGF, P < 0.001; Ang-1, P < 0.001; pAng-1, P = 0.04). There were no correlations with blood pressure or the levels of sPsel.

CONCLUSION

Levels of plasma and intra-platelet VEGF and Ang-1 are increased in hypertension and are decreased with treatment. Platelet levels of VEGF and Ang-1 may be related to platelet activation but may also involve other mechanisms (for example, the general vascular and haemodynamic changes) that are seen in hypertension.

Carotid Plaque Echomorphology and Serum Vascular Endothelial Growth Factor Levels

Neovascularization in atherosclerotic plaques plays an essential role in the progression and rupture of plaques. Vascular endothelial growth factor (VEGF) is an important angiogenic factor. Echomorphologic evaluation of carotid plaques using computer-assisted imaging was found to have a good correlation with the histology of the lesion. The aim of this study was to investigate whether the serum VEGF level could be a determinant of the echomorphology of the carotid plaque. In 28 carotid plaques causing 60-99% stenosis, serum VEGF levels and the mean gray value (MGV) of three-dimensional image of the carotid plaques were measured. A statistically significant inverse correlation was found between serum VEGF concentrations and MGVs (Spearman's correlation coefficient: -0.415, p = 0.028). Our finding indicates that in patients with > or =60% carotid stenosis the serum VEGF levels are associated with the echogenicity of the atherosclerotic plaque.

Prevention and Reversal of Premature Endothelial Cell Senescence and Vasculopathy in Obesity-Induced Diabetes by Ebselen

Although the accelerated atherosclerosis and premature aging of the cardiovascular system in patients with metabolic syndrome have been appreciated, the mechanisms of their development and potential therapeutic interventions remain unresolved. Our previous studies implicated advanced glycosylation end products in development of premature senescence preventable with a peroxynitrite scavenger, ebselen. Therefore, the effect of ebselen on endothelial senescence and vasculopathy in a model of metabolic syndrome--Zucker diabetic rats (ZDF)--was investigated. Ebselen decreased the abundance of 3-nitrotyrosine-modified proteins in ZDF rats. A 6-fold increase in the number of senescent endothelial cells in 22-week-old ZDF was prevented by ebselen. Development of vasculopathy, as collectively judged by the acetylcholine-induced vasorelaxation, NO production, angiogenic competence, and number of circulating microparticles, was almost completely prevented when ebselen was administered from 8 to 22 weeks and partially reversed when the treatment interval was 13 to 22 weeks. In conclusion, premature senescence of endothelial cells is progressively rampant in ZDF rats and is associated with the signs of severe vasculopathy. In addition, prevention of premature senescence of vascular endothelium through controlled decrease in nitrotyrosine formation was chronologically associated with the amelioration of vasculopathy, lending support to the idea of the pathogenetic role of premature senescence of endothelial cells in diabetic macrovasculopathy.