Endothelial function and dysfunction. Part I: Methodological issues for assessment in the different vascular beds: a statement by the Working Group on Endothelin and Endothelial Factors of the European Society of Hypertension

Blood pressure-independent reduction in proteinuria and arterial stiffness after acute endothelin-a receptor antagonism in chronic kidney disease

Endothelin 1 is implicated in the development and progression of chronic kidney disease and associated cardiovascular disease. We, therefore, studied the effects of selective endothelin-A receptor antagonism with BQ-123 on key independent surrogate markers of cardiovascular risk (blood pressure, proteinuria and renal hemodynamics, arterial stiffness, and endothelial function) in patients with nondiabetic chronic kidney disease. In a double-blind, randomized crossover study, 22 subjects with proteinuric chronic kidney disease received, on 2 separate occasions, placebo or BQ-123. Ten of these subjects also received nifedipine (10 mg) as an active control for the antihypertensive effect of BQ-123. Blood pressure, pulse wave velocity, flow-mediated dilation, renal blood flow, and glomerular filtration rate were monitored after drug dosing. BQ-123 reduced blood pressure (mean arterial pressure: -7+/-1%; P<0.001 versus placebo) and increased renal blood flow (17+/-4%; P<0.01 versus placebo). Glomerular filtration rate remained unchanged. Proteinuria (-26+/-4%; P<0.01 versus placebo) and pulse wave velocity (-5+/-1%; P<0.001 versus placebo) fell after BQ-123, but flow-mediated dilation did not change. Nifedipine matched the blood pressure and renal blood flow changes seen with BQ-123. Nevertheless, BQ-123 reduced proteinuria (-38+/-3% versus 26+/-11%; P<0.001) and pulse wave velocity (-9+/-1% versus -3+/-1%; P<0.001) to a greater extent than nifedipine. Selective endothelin-A receptor antagonism reduced blood pressure, proteinuria, and arterial stiffness on top of standard treatment in renal patients. Furthermore, these studies suggest that the reduction in proteinuria and arterial stiffness is partly independent of blood pressure. If maintained longer term, selective endothelin-A receptor antagonism may confer cardiovascular and renal benefits in patients with chronic kidney disease.

Obstructive sleep apnea and cardiovascular disease

Obstructive sleep apnea (OSA) is a common yet an under-diagnosed sleep related breathing disorder affecting predominantly middle-aged men. OSA is associated with many adverse health outcomes, including cardiovascular disease. Common OSA associated/induced cardiovascular disorders include coronary artery disease, heart failure, hypertension, cardiac arrhythmias and stroke, which further increase morbidity and mortality in the OSA population. Endothelial dysfunction, coagulopathy, impaired sympathetic drive, oxidative and inflammatory stress are the pathophysiological pathways suggested for the development of cardiovascular disease in OSA. The evidence would suggest that OSA should be considered as a cardiovascular risk factor, and is a treatable condition. Multiple studies using Continuous Positive Airway Pressure (CPAP) have shown improvements in the clinical state as well as retardation of disease progression. Therefore, patients with cardiovascular disease should be proactively screened for OSA and vice versa.

Endothelium-dependent contractions and endothelial dysfunction in human hypertension

The endothelium is a crucial regulator of vascular physiology, producing in healthy conditions several substances with a potent antiatherosclerotic properties. Accordingly, the presence of endothelial dysfunction is associated with subclinical atherosclerosis and with an increased future risk of cardiovascular events. A large body of evidence supports the fundamental role of nitric oxide (NO) as the main endothelium-derived relaxing factor. However, in the presence of pathological conditions, such as hypertension, endothelial cells, in response to a number of agents and physical stimuli, become also a source of endothelium-derived contracting factors (EDCFs), including endothelins and angiotensin II and particularly cyclooxygenase-derived prostanoids and superoxide anions. These latter were at first identified as responsible for impaired endothelium-dependent vasodilation in patients with essential hypertension. However, cyclooxygenase-dependent EDCFs production is characteristic of the aging process, and essential hypertension seems to only anticipate the phenomenon. It is worth noting that both in aging and hypertension EDCF production is associated with a parallel decrease in NO availability, suggesting that this substance could be oxygen free radicals themselves. Accordingly, in hypertension both indomethacin, a cyclooxygenase inhibitor, and vitamin C, an antioxidant, increase the vasodilation to acetylcholine by restoring NO availability. In conclusion, hypertension is characterized by a decline in endothelial function, associated with a progressive decrease in NO bioavailability and increase in the production of EDCF. The mechanisms that regulate the balance between NO and EDCF, and the processes transforming the endothelium from a protective organ to a source of vasoconstrictor, proaggregatory and promitogenic mediators remain to be determined.

Coronary artery endothelial dysfunction is positively correlated with low density lipoprotein and inversely correlated with high density lipoprotein subclass particles measured by nuclear magnetic resonance spectroscopy

OBJECTIVE

The association between cholesterol and endothelial dysfunction remains controversial. We tested the hypothesis that lipoprotein subclasses are associated with coronary endothelial dysfunction.

METHODS AND RESULTS

Coronary endothelial function was assessed in 490 patients between November 1993 and February 2007. Fasting lipids and nuclear magnetic resonance (NMR) lipoprotein particle subclasses were measured. There were 325 females and 165 males with a mean age of 49.8+/-11.6 years. Coronary endothelial dysfunction (epicardial constriction>20% or increase in coronary blood flow<50% in response to intracoronary acetylcholine) was diagnosed in 273 patients, the majority of whom (64.5%) had microvascular dysfunction. Total cholesterol and LDL-C (low density lipoprotein cholesterol) were not associated with endothelial dysfunction. One-way analysis and multivariate methods adjusting for age, gender, diabetes, hypertension and lipid-lowering agent use were used to determine the correlation between lipoprotein subclasses and coronary endothelial dysfunction. Epicardial endothelial dysfunction was significantly correlated with total (p=0.03) and small LDLp (LDL particles) (p<0.01) and inversely correlated with total and large HDLp (high density lipoprotein particles) (p<0.01).

CONCLUSIONS

Epicardial, but not microvascular, coronary endothelial dysfunction was associated directly with LDL particles and inversely with HDL particles, suggesting location-dependent impact of lipoprotein particles on the coronary circulation.

Fixed dose combination of perindopril and indapamide improves peripheral vascular function in essential hypertensive patients

BACKGROUND

The effect on endothelium-dependent and independent vasodilation of 24-week treatment with a fixed-dose combination of perindopril/indapamide (2/0.625 mg, daily) and atenolol (50 mg, daily), was evaluated in 62 untreated essential hypertensive patients according a double-blind, parallel group, randomized study.

METHODS

Brachial artery flow-mediated dilation (FMD), response to sublingual glyceril trinitrate (GTN, 25 microg) and to cold pressor test (CPT) were measured at baseline and after treatments at 12 and 24 weeks, as change in diameter from ultrasound scans by a computerized system.

RESULTS

Blood pressure (BP) was (P < 0.001) reduced in both groups, but to a greater (P < 0.01) extent in the perindopril/indapamide group. After 24 weeks, FMD was significantly increased (P < 0.01) by perindopril/indapamide (from 5.0 +/- 2.1 to 6.0 +/- 1.7%) but not by atenolol (from 5.1 +/- 1.8 to 5.5 +/- 1.8%). Improvement in FMD was not statistically related to BP reduction. Response to GTN was also significantly (P < 0.05) increased by perindopril/indapamide (from 6.2 +/- 1.9 to 6.9 +/- 1.7%), but not by atenolol (from 6.1 +/- 2.8 to 6.6 +/- 2.6%). Improvement in GTN response was significantly (P < 0.05) related to BP reduction. Response to CPT was significantly increased (P < 0.001) by perindopril/indapamide after 12 and 24 weeks, whereas atenolol significantly (P < 0.05) improved it only after 24 weeks.

CONCLUSIONS

Treatment with perindopril/indapamide improves endothelium-dependent vasodilation in comparison with atenolol. This improvement was observed without significant relations with BP changes, suggesting a pressure-independent effect. Improvement in endothelium-independent and sympathetic-associated vasodilation was also observed. These results suggests that long term therapy with a fixed-dose combination of perindopril/indapamide affords vascular protection in hypertensive patients.

Comparison of skin microvascular reactivity with hemostatic markers of endothelial dysfunction and damage in type 2 diabetes

Aim:

Patients with non-insulin-dependent diabetes mellitus (NIDDM) are at increased cardiovascular risk due to an accelerated atherosclerotic process. The present study aimed to compare skin microvascular function, pulse wave velocity (PWV), and a variety of hemostatic markers of endothelium injury [von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA), tissue factor pathway inhibitor (TFPI), and the soluble form of thrombomodulin (s-TM)] in patients with NIDDM.

Methods:

54 patients with NIDDM and 38 sex- and age-matched controls were studied. 27 diabetics had no overt micro- and/or macrovascular complications, while the remainder had either or both. The forearm skin blood flow was assessed by laser-Doppler imaging, which allowed the measurement of the response to iontophoretically applied acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation), as well as the reactive hyperemia triggered by the transient occlusion of the circulation.

Results:

Both endothelial and non-endothelial reactivity were significantly blunted in diabetics, regardless of the presence or the absence of vascular complications. Plasma vWF, TFPI and s-TM levels were significantly increased compared with controls only in patients exhibiting vascular complications. Concentrations of t-PA and PAI-1 were significantly increased in the two groups of diabetics versus controls.

Conclusion:

In NIDDM, both endothelium-dependent and -independent microvascular skin reactivity are impaired, whether or not underlying vascular complications exist. It also appears that microvascular endothelial dysfunction is not necessarily associated in NIDDM with increased circulating levels of hemostatic markers of endothelial damage known to reflect a hypercoagulable state.

Dietary intake of fruits and vegetables improves microvascular function in hypertensive subjects in a dose-dependent manner

BACKGROUND

Observational evidence has consistently linked increased fruit and vegetable consumption with reduced cardiovascular morbidity; however, there is little direct trial evidence to support the concept that fruit and vegetable consumption improves vascular function. This study assessed the dose-dependent effects of a fruit and vegetable intervention on arterial health in subjects with hypertension.

METHODS AND RESULTS

After a 4-week run-in period during which fruit and vegetable intake was limited to 1 portion per day, participants were randomized to consume either 1, 3, or 6 portions daily for the next 8 weeks. Endothelium-dependent and -independent arterial vasodilator responses were assessed by venous occlusion plethysmography in the brachial circulation before and after intervention. Compliance was monitored with serial contemporaneous 4-day food records and by measuring concentrations of circulating dietary biomarkers. A total of 117 volunteers completed the 12-week study. Participants in the 1-, 3-, and 6-portions/d groups reported consuming on average 1.1, 3.2, and 5.6 portions of fruit and vegetables, respectively, and serum concentrations of lutein and beta-cryptoxanthin increased across the groups in a dose-dependent manner. For each 1-portion increase in reported fruit and vegetable consumption, there was a 6.2% improvement in forearm blood flow responses to intra-arterial administration of the endothelium-dependent vasodilator acetylcholine (P=0.03). There was no association between increased fruit and vegetable consumption and vasodilator responses to sodium nitroprusside, an endothelium-independent vasodilator.

CONCLUSIONS

The present study illustrates that among hypertensive volunteers, increased fruit and vegetable consumption produces significant improvements in an established marker of endothelial function and cardiovascular prognosis.

Endothelial dysfunction and cardiovascular risk factors

The endothelium plays an integral role in the regulation of vascular tone, platelet activity, leukocyte adhesion, and thrombosis and is intimately involved in the development of atherosclerosis. Endothelial dysfunction has been observed in patients with established coronary artery disease or coronary risk factors, both in the coronary and peripheral vasculature. Therapeutic interventions with lipid-lowering drugs, ACE inhibitors, physical activity, and antioxidant agents have been shown to improve endothelial function in coronary and peripheral vessels. This systemic manifestation and improvement of endothelial function suggests that a common mechanism may contribute to endothelial dysfunction in the coronary and peripheral circulation.

TARGET AUDIENCE

Internist, Cardiologists, Family physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to define the participation of cardiovascular risk factors in the various complications associated with endothelial dysfunction.

Evaluation of plasma and urinary levels of 6-keto-prostaglandin F1alpha as a marker for asymptomatic myxomatous mitral valve disease in dogs

Endothelial dysfunction might be involved in the pathogenesis of myxomatous mitral valve disease (MMVD). The aims of this study were (1) to validate an enzyme immunoassay (EIA) for canine 6-keto-prostaglandin (PG)F(1alpha) (prostacyclin metabolite and marker for endothelial function) and (2) to compare plasma and urinary 6-keto-PGF(1alpha) in dogs with asymptomatic MMVD. The study included two breeds predisposed to MMVD and two control groups (Cairn terriers and dogs of different breeds). Echocardiography was used to estimate the severity of MMVD. The intra- and inter-assay coefficients of variation were between 3.1% and 24.5% in the assay range. No echocardiographic parameter was correlated with plasma or urinary 6-keto-PGF(1alpha) (P>0.05), but all control dogs had lower urinary 6-keto-PGF(1alpha) (P<0.02) and the Cairn terriers had higher plasma 6-keto-PGF(1alpha) (P<0.02). The EIA appeared valid for measuring canine 6-keto-PGF(1alpha) in plasma and urine. It is suggested that 6-keto-PGF(1alpha) levels are related to breed and not MMVD in asymptomatic stages.

Evaluating endothelial function of the common carotid artery: an in vivo human model

BACKGROUND AND AIMS

Flow mediated dilation (FMD) of peripheral conduit arteries is a well-established tool to evaluate endothelial function. The aims of this study are to apply the FMD model to cerebral circulation by using acetazolamide (ACZ)-induced intracranial vasodilation as a stimulus to increase common carotid artery (CCA) diameter in response to a local increase of blood flow velocity (BFV).

METHODS AND RESULTS

In 15 healthy subjects, CCA end-diastolic diameter and BFV, middle cerebral artery (MCA) BFV and mean arterial blood pressure (MBP) were measured at basal conditions, after an intravenous bolus of 1g ACZ, and after placebo (saline) sublingual administration at the 15th and 20th minute. In a separate session, the same parameters were evaluated after placebo (saline) infusion instead of ACZ and after 10 microg/m(2) bs and 300 microg of glyceryl trinitrate (GTN), administered sublingually, at the 15th and 20th minute, respectively. After ACZ bolus, there was a 35% maximal MCA mean BFV increment (14th minute), together with a 22% increase of mean CCA end-diastolic BFV and a CCA diameter increment of 3.9% at the 3rd minute (p=0.024). There were no MBP significant variations up to the 15th minute (p=0.35). After GTN administration, there was a significant increment in CCA diameter (p<0.00001).

CONCLUSIONS

ACZ causes a detectable CCA dilation in healthy individuals concomitantly with an increase in BFV. Upon demonstration that this phenomenon is endothelium dependent, this experimental model might become a valuable tool to assess endothelial function in the carotid artery.

End-organ dysfunction and cardiovascular outcomes: the role of the microcirculation

Risk factors for cardiovascular disease mediate their effects by altering the structure and function of wall and endothelial components of arterial blood vessels. A pathological change in the microcirculation plays a pivotal role in promoting end-organ dysfunction that not only predisposes to further organ damage, but also increases the risk for future macrovascular events. The microcirculation is recognized as the site where the earliest manifestations of cardiovascular disease, especially inflammatory responses, occur that may play a pivotal role in driving the atherosclerotic process in conduit vessels. Furthermore, the vast surface area of the endothelium compared with conduit vessels means that the vascular effects of endothelial dysfunction or activation will be most apparent in this section of the vasculature. Current techniques providing indices of vascular health focus on large arteries without providing insight into the structure and function of small vessels. Techniques capable of detecting microvascular damage and monitoring the response to therapeutic interventions, especially in vulnerable target organs of interest, may improve risk stratification and represent a valuable surrogate for future cardiovascular outcome.

Measurement of endothelial function and its clinical utility for cardiovascular risk

Over the past two decades, the central role of the endothelium in the initiation, progression, and clinical sequelae of atherosclerosis has been increasingly recognized. Assessment of the pathobiology of the endothelium and its ability to act as a potential therapeutic target remains an area of active research interest. Whilst endothelial function has been shown to be a marker for risk of cardiovascular events in high-risk groups, there remains considerable debate about the most appropriate way to assess this. We discuss the different clinical methods to assess endothelial function, focusing on flow-mediated dilatation (FMD) of the brachial artery, highlighting the importance of using a standardized methodology, as well as discussing the clinical limitations of using FMD in individuals.

Clinical Use and Pathogenetic Basis of Laboratory Tests for the Evaluation of Primary Arterial Hypertension

This review focuses on the laboratory biochemical tests that are useful in the diagnostic approach to the hypertensive patient. A "minimal" diagnostic laboratory work-up, including a small number of tests that are simple and relatively inexpensive, is first described. Because these tests provide basic information on the presence of major cardiovascular (CV) risk factors and target organ damage, and might give some clues to the presence of a secondary form of hypertension (HT), they should be performed on all patients presenting with HT. Other tests that are aimed at assessing the overall CV risk, a major determinant of prognosis that dictates the therapeutic strategy in the individual HT patient, are then discussed. They allow identification of major CV risk factors and associated clinical conditions which, if present, lead to a substantial change of therapeutic strategy. The role of C-reactive protein as a marker of atherosclerosis and its predictive value for CV events are also discussed. Finally, a section is devoted to tests that are currently confined to research purposes, such as markers of endothelial function including endothelin-1, homocysteine and genetic analysis.

Prognostic role of flow-mediated dilatation of the brachial artery in hypertensive patients

BACKGROUND

The prognostic role of endothelial dysfunction, as evaluated by flow-mediated vasodilatation of the brachial artery, has been demonstrated in patients at very high risk. We aimed to investigate whether flow-mediated vasodilatation predicts cardiovascular events in uncomplicated hypertensive patients.

METHODS AND RESULTS

A total of 172 prospectively identified uncomplicated hypertensive patients (age 56 +/- 8 years, 41% women, 48 with diabetes mellitus type 2) were studied. At baseline all patients were untreated and underwent baseline standard laboratory examination. A standard echocardiogram was performed for the evaluation of left ventricular anatomy and function and patients with systolic dysfunction or left ventricular wall motion abnormalities were excluded. Endothelial function was measured as flow-mediated vasodilatation of the brachial artery using high-resolution ultrasound. Patients were followed for 95 +/- 37 months (range 2-136 months). A first nonfatal or fatal cardiovascular event occurred in 32 patients. The incidence of cardiovascular events was 1.4 and 3.1 per 100 patient-years in patients with a flow-mediated vasodilatation below and above the median value (4.7%), respectively (P < 0.005 by the log-rank test). In Cox analysis, controlling for age, sex, glycemia, cholesterol, smoking, BMI, systolic and diastolic blood pressure at baseline and left ventricular mass index, a low flow-mediated vasodilatation conferred an increased risk of cardiovascular events (odds ratio 2.67, 95% confidence interval 1.17 to 6.1, P = 0.02).

CONCLUSION

The presence of endothelial dysfunction, as evaluated by flow-mediated vasodilatation of the brachial artery, identifies hypertensive patients at increased risk of nonfatal and fatal cardiovascular events.

Endothelin-1 and F2-isoprostane relate to and predict renal dysfunction in hypertensive patients

BACKGROUND

Hypertension and additional non-traditional risk factors can damage the kidney directly and by promoting atherogenesis. Evidence indicates that increased oxidative stress and inflammation may mediate a large part of the effects of risk factors on the kidney. We hypothesized that in hypertensive patients (HT), oxidative stress, measured as 8-ISO-prostaglandin F2alpha (8-ISO-PGF2alpha), should raise paralleling decreasing renal function and should correlate with estimated glomerular filtration rate (eGFR).

METHODS

In 626 HT with renal function ranging from stages 1 to 5 and 100 healthy controls, plasma levels of 8-ISO-PGF2alpha, high-sensitivity C-reactive protein (CRP), transforming growth factor-beta (TGF-beta) and endothelin-1 (ET-1) were measured. GFR was estimated by the Modification of Diet in Renal Disease study equation.

RESULTS

When HT were stratified according to renal function stages, 8-ISO-PGF2alpha, CRP, TGF-beta and ET-1 increased progressively and significantly with decreasing eGFR. The multiple regression analysis, considering eGFR as a dependent variable, showed that 8-ISO-PGF2alpha (beta = -0.361, P < 0.000001), ET-1 (beta = -0.197, P < 0.0001) and TGF-beta (beta = -0.170, P < 0.0004) correlated independently with eGFR. All biomarkers were good predictors of eGFR <60 ml/min/1.73 m(2) [receiver-operator-curve (ROC) areas]. ET-1 was shown to be the best predictor with a ROC area = 0.938; with a threshold of 4 pg/ml, 91% sensitivity and 85% specificity were observed, whereas 8-ISO had a ROC area = 0.931, and for a threshold of 329 pg/ml, sensitivity and specificity were 89%, respectively. In contrast, CRP showed the lower predictive value with a ROC area = 0.917; with a threshold of 2.52 mg/l, an 87% sensitivity and an 83% specificity were obtained.

CONCLUSIONS

Our findings are a clear-cut demonstration of a strong and negative correlation of both oxidative stress and ET-1 with renal function stages in HT. ET-1 and 8-isoprostane are predictive of eGFR.

Tea, flavonoids, and nitric oxide-mediated vascular reactivity

Epidemiological evidence supports the concept that diets rich in fruits and vegetables promote health and attenuate or delay the onset of cardiovascular disease (CVD). Although a variety of factors contribute to the beneficial effects of plant foods, much attention has been addressed to plant polyphenols. In this regard, in the daily Western diet, both black and green teas contribute to a relevant proportion of total phenol intake. The more abundant class of flavonoids that is present in teas is represented by flavanols, i.e., catechin, epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. Studies using animal models of atherosclerosis indicate that dietary flavonoid consumption delays atherosclerotic plaque development. Accordingly, an inverse association between tea intake and CVD has been demonstrated. Further, flavonoids can reduce endothelial dysfunction, i.e., the key step in the development of atherosclerosis. Concordantly, human data suggest that tea may reduce blood pressure levels. Despite this, although they often show that tea may have cardiovascular protective effects, results from epidemiological studies exploring the association between tea and health are controversial. Conflicting results may be caused by disparate study designs and flavonoid contents in different kinds of tea. Thus, because tea is a popular beverage worldwide, and several studies have shown that it is protective against CVD, further studies are needed to determine the role of tea in primary and secondary cardiovascular prevention.

Patients with primary antiphospholipid antibody syndrome and without associated vascular risk factors present a normal endothelial function

INTRODUCTION

Primary antiphospholipid antibody syndrome (PAPS) is characterized by venous or arterial thrombosis and positive antiphospholipid antibodies. It is controversial whether PAPS patients have early atherosclerosis. Endothelial dysfunction is an early event in the natural history of atherosclerosis. Aim of our study was to compare endothelial function of patients with PAPS and no associated risk factors with that of age- and sex-matched controls.

MATERIALS AND METHODS

Patients with PAPS, carefully selected to exclude all known risk factors for cardiovascular diseases, estrogen therapy, pregnancy, intake of drugs affecting endothelial function, vitamins or antioxidants, were included in a case-control study. Controls were age- (+/-5 years) and sex-matched subjects with the same exclusion criteria but without PAPS. Flow-mediated dilation of the brachial artery and some plasmatic markers of endothelial and platelet activation were measured. Measures are expressed as mean+/-SEM.

RESULTS

Twenty cases (mean age 42+/-4.0 years, 11 females) and 39 controls (mean age 41+/-2.9, 22 females) were studied. FMD was 5.7+/-0.8% in cases (95% CI: 4.1 to 7.3) and 6.8+/-0.5% (5.7 to 7.9) in controls (p=NS). Plasma von Willebrand factor was 128+/-11.3% and 134.2+/-16.1% in cases and controls, respectively (p=NS). Soluble P-selectin and soluble CD40L were 94.1+/-4.9 ng/ml and 0.7+/-0.1 ng/ml in cases and 87.7+/-4.0 ng/ml and 1.0+/-0.2 in controls, respectively (p=NS). In a substudy, circulating progenitor and mature endothelial cells were comparable between the two groups.

CONCLUSIONS

Endothelial function in patients with PAPS and no associated risk factors is similar to that of age- and sex- matched controls. These data suggest that the alterations leading to thrombosis in PAPS concern primarily the clotting system.

Parathyroid hormone is inversely related to endothelin-1 in patients on haemodialysis

AIM

Parathyroid hormone secretion is mainly influenced by hypocalcaemia, hyperphosphataemia and vitamin D deficiency. However, previous in vitro and in vivo studies showed that endothelin-1 can influence parathyroid hormone secretion. This study was aimed at evaluating this relationship in vivo in uraemic patients.

METHODS

Parathyroid hormone and endothelin-1 plasma concentrations were measured in 67 haemodialysed patients. Patients with history of cardiovascular diseases and those with parathyroid adenoma were excluded.

RESULTS

Plasma levels of endothelin-1 were found to be inversely related to those of parathyroid hormone (P < 0.04) The multiple regression analysis, carried out considering parathyroid hormone as a dependent variable, and including age, sex, blood pressure, calcium x phosphorus product, and endothelin-1, demonstrated that the independent correlates of parathyroid hormone were endothelin-1 (beta = -0.276; P = 0.015), and calcium x phosphorus product (beta = 0.417; P < 0.0001).

CONCLUSION

For the first time in vivo, we demonstrated an inverse independent relationship between endothelin-1 and parathyroid hormone in haemodialysed patients. Because both endothelin-1 and parathyroid hormone are endowed with well-known harmful actions on cardiovascular apparatus, whether such inverse relation may really influence the natural history of cardiovascular damage due to secondary hyperparathyroidism remains to be elucidated.

Impaired brachial artery endothelial flow-mediated dilation and orthostatic stress in hemodialysis patients

PURPOSE

Chronic kidney disease (CKD) is associated with an impaired endothelial function, which may contribute to cardiovascular events. Whether impairment in endothelial function is involved in the circulatory response to orthostatic stress is unknown. We assessed endothelial function via brachial artery flow-mediated dilation (BAFMD), an index of endothelial-dependent vasodilation.

METHODS

We measured changes in brachial artery diameter (BAD) and blood flow by Doppler ultrasound in 35 CKD patients on hemodialysis, 37 young healthy controls (HC) and 50 non-uremic matched controls (MC), in the supine position and after 60 degrees head-up tilting (HUT).

RESULTS

In the supine position, endothelial flow-mediated BAD was significantly increased in HC (p<0.001) and MC (p<0.01) while no significant changes were detected in CKD. Mean percent blood flow changes were HC+323.5%, MC+195.1% and CKD+158.8% (HC vs. CKD p<0.001; HC vs. MC p<0.001; MC vs. CKD p=0.04). Similarly, during HUT mean BAD and blood flow increases were significantly impaired in CKD patients.

CONCLUSION

In CKD patients, an impaired response in the physiologic vascular reactivity, suggesting endothelial dysfunction, was found in the supine position and after orthostasis by BAFMD. Our results are in favor of a possible adjunctive role of uremia in the abnormal brachial artery response.

Cholesterol lowering is more important than pleiotropic effects of statins for endothelial function in patients with dysglycaemia and coronary artery disease

AIMS

The importance of pleiotropic effects of statins on endothelial function and inflammatory markers was investigated in patients with dysglycaemia and coronary artery disease (CAD).

METHODS AND RESULTS

Thirty-nine patients were randomized to simvastatin 80 mg daily (S80; n = 20) or ezetimibe 10 mg and simvastatin 10 mg daily (E10/S10; n = 19) for 6 weeks, aiming at similar cholesterol reduction. Endothelial function, evaluated by brachial artery flow-mediated vasodilatation (FMD) and the effect of endothelin receptor blockade, serum lipids, and inflammatory markers were evaluated at baseline and follow-up. At follow-up, low-density lipoprotein cholesterol decreased from 3.1 (2.8-3.4) (median and quartiles) to 1.5 mmol/L (1.4-1.7) and from 3.0 (2.5-3.4) to 1.3 mmol/L (1.1-1.8), in the S80 and E10/S10 groups, respectively. In the entire study group, FMD increased from 4.3% (3.4-6.1) at baseline to 5.5% (3.4-6.6) at follow-up, while C-reactive protein decreased from 3.1 (1.7-7.6) to 2.3 mg/L (0.9-6.5). The changes in FMD and C-reactive protein from baseline to follow-up were not significantly different between patients on S80 and E10/S10 groups. Endothelin blockade enhanced endothelium-dependent vasodilatation both at baseline and follow-up.

CONCLUSION

Lipid lowering is more important than pleiotropic effects of statins for improvement in endothelial function and inflammatory markers in patients with dysglycaemia and CAD.

Angiotensin-converting enzyme inhibition improves vascular function in rheumatoid arthritis

BACKGROUND

The excess in cardiovascular risk in patients with rheumatoid arthritis provides a strong rationale for early therapeutical interventions. In view of the similarities between atherosclerosis and rheumatoid arthritis and the proven benefit of angiotensin-converting enzyme inhibitors in atherosclerotic vascular disease, it was the aim of the present study to delineate the impact of ramipril on endothelial function as well as on markers of inflammation and oxidative stress in patients with rheumatoid arthritis.

METHODS AND RESULTS

Eleven patients with rheumatoid arthritis were included in this randomized, double-blind, crossover study to receive ramipril in an uptitration design (2.5 to 10 mg) for 8 weeks followed by placebo, or vice versa, on top of standard antiinflammatory therapy. Endothelial function assessed by flow-mediated dilation of the brachial artery, markers of inflammation and oxidative stress, and disease activity were investigated at baseline and after each treatment period. Endothelial function assessed by flow-mediated dilation increased from 2.85+/-1.49% to 4.00+/-1.81% (P=0.017) after 8 weeks of therapy with ramipril but did not change with placebo (from 2.85+/-1.49% to 2.84+/-2.47%; P=0.88). Although systolic blood pressure and heart rate remained unaltered, diastolic blood pressure decreased slightly from 78+/-7 to 74+/-6 mm Hg (P=0.03). Tumor necrosis factor-alpha showed a significant inverse correlation with flow-mediated dilation (r=-0.408, P=0.02), and CD40 significantly decreased after ramipril therapy (P=0.049).

CONCLUSIONS

Angiotensin-converting enzyme inhibition with 10 mg/d ramipril for 8 weeks on top of current antiinflammatory treatment markedly improved endothelial function in patients with rheumatoid arthritis. This finding suggests that angiotensin-converting enzyme inhibition may provide a novel strategy to prevent cardiovascular events in these patients.

Absence of vascular remodelling in a high angiotensin-II state (Bartter's and Gitelman's syndromes): implications for angiotensin II signalling pathways

BACKGROUND

Angiotensin II (Ang II) is a powerful proinflammatory cytokine and growth factor that activates NF-kappaB, as well as NAD(P)H oxidase, and thus is a key factor for the induction and progression of cardiovascular diseases. Our previous studies have shown high Ang II and high blood pressure-driven proatherogenic remodelling in an animal model. To further explore Ang II in proatherogenic vascular remodelling independent of blood pressure, we used Bartter's/Gitelman's syndrome (BS/GS) patients given their elevated plasma Ang II, yet normo/hypotension, because extensive mechanistic studies in these patients suggest they are a good model to explore Ang II-mediated signalling.

METHODS

The study evaluated BS/GS patients for nitric oxide-dependent (FMD) and -independent vasodilation and intima-media thickness (IMT) of the carotid arteries compared with healthy subjects and essential hypertensive patients.

RESULTS

The results showed the absence of IMT growth in BS/GS patients as cumulative mean-IMT and mean maximum-IMT levels in BS/GS did not differ from normotensives: 0.58 +/- 0.09 mm versus 0.60 +/- 0.09 and 0.67 +/- 0.09 versus 0.70 +/- 0.13 respectively, P = ns, but were significantly lower compared with hypertensive patients: 0.69 +/- 0.13, P < 0.046 and 0.85 +/- 0.19, P < 0.018, respectively. FMD was increased in BS/GS versus hypertensives or normotensive controls (10.8 +/- 2.7% versus 6.5 +/- 2.3 and 8.7 +/- 1.9, P < 0.002 respectively) while endothelium-independent dilation did not differ (10.2 +/- 3.6% versus 7.2 +/- 1.9 and 8.2 +/- 3.3, P = ns) between groups.

CONCLUSIONS

Our study in BS/GS provides to our knowledge the first clinical data that point to a direct proatherogenic role for Ang II. However, because the data are derived from findings in BS/GS and therefore are indirect, further studies in this and other models using more direct approaches should be pursued to demonstrate a direct proatherogenic effect of Ang II as well as further studies on Ang II type 2 receptor (AT2R) signalling that the spectrum of findings of this and other studies indicate as involved in the lack of vascular remodelling.

Anterior translation at the glenohumeral joint: a cause of axillary artery compression?

BACKGROUND

Lesions to the axillary artery are reported in overhead athletes. One speculated cause is repeated transient compression by the humeral head due to excessive laxity at the glenohumeral joint.

HYPOTHESES

(1) Anterior translation of the glenohumeral joint alters axillary artery diameter and blood flow characteristics, and (2) individuals demonstrating inducible axillary artery compression with the arm in an overhead position (as indicated by diameter and blood flow characteristics) will demonstrate greater magnitudes of anterior translation.

STUDY DESIGN

Descriptive laboratory study.

METHODS

After receiving ethical approval and screening for problematic conditions/injuries, 26 subjects were tested (10 men and 16 women; mean age [standard deviation], 25 years [4]). Axillary artery diameter and peak systolic velocity were measured with B-mode and Doppler ultrasound before, during, and after glenohumeral anterior translation at 90 degrees of abduction, 60 degrees of external rotation, and 30 degrees of horizontal flexion, and at baseline and a simulated overhead throwing position (120 degrees of abduction, 90 degrees of external rotation, and 30 degrees of horizontal extension). The magnitude of anterior translation was captured with B-mode ultrasound using a posterior transverse approach.

RESULTS

Application of the glide resulted in a significant (F(2,21) = 9.965, P = .001) reduction in axillary artery diameter and a significant increase in peak systolic velocity (F(2,21) = 5.286, P = .014). Subjects demonstrating clinically significant levels of axillary artery compression ( > 50% reduction in vessel diameter with the arm in the overhead throwing position) exhibited significantly (t = -2.260, P = .040) greater ranges of anterior translation at the glenohumeral joint than the 9 subjects who exhibited < 10% reduction in arterial diameter.

CONCLUSIONS

This investigation provides the first empirical support for the clinical opinion that glenohumeral anterior translation could be a mechanism for inducible axillary artery compression.

CLINICAL RELEVANCE

The response of axillary artery hemodynamics in normal, healthy individuals is the first step in the process of determining whether the finding of inducible axillary artery compression in overhead athletes with arterial pathology is related to glenohumeral translation.

Endothelial dysfunction in diabetes mellitus

Diabetes mellitus is associated with an increased risk of cardiovascular disease, even in the presence of intensive glycemic control. Substantial clinical and experimental evidence suggest that both diabetes and insulin resistance cause a combination of endothelial dysfunctions, which may diminish the anti-atherogenic role of the vascular endothelium. Both insulin resistance and endothelial dysfunction appear to precede the development of overt hyperglycemia in patients with type 2 diabetes. Therefore, in patients with diabetes or insulin resistance, endothelial dysfunction may be a critical early target for preventing atherosclerosis and cardiovascular disease. Microalbuminuria is now considered to be an atherosclerotic risk factor and predicts future cardiovascular disease risk in diabetic patients, in elderly patients, as well as in the general population. It has been implicated as an independent risk factor for cardiovascular disease and premature cardiovascular mortality for patients with type 1 and type 2 diabetes mellitus, as well as for patients with essential hypertension. A complete biochemical understanding of the mechanisms by which hyperglycemia causes vascular functional and structural changes associated with the diabetic milieu still eludes us. In recent years, the numerous biochemical and metabolic pathways postulated to have a causal role in the pathogenesis of diabetic vascular disease have been distilled into several unifying hypotheses. The role of chronic hyperglycemia in the development of diabetic microvascular complications and in neuropathy has been clearly established. However, the biochemical or cellular links between elevated blood glucose levels, and the vascular lesions remain incompletely understood. A number of trials have demonstrated that statins therapy as well as angiotensin converting enzyme inhibitors is associated with improvements in endothelial function in diabetes. Although antioxidants provide short-term improvement of endothelial function in humans, all studies of the effectiveness of preventive antioxidant therapy have been disappointing. Control of hyperglycemia thus remains the best way to improve endothelial function and to prevent atherosclerosis and other cardiovascular complications of diabetes. In the present review we provide the up to date details on this subject.

Atherosclerosis in patients with biopsy-proven giant cell arteritis

OBJECTIVE

To examine the presence of atherosclerosis in a series of giant cell arteritis (GCA) patients attended to in a community hospital and to determine whether clinical features or steroid therapy might be associated with the development of atherosclerotic disease.

METHODS

Forty consecutive patients diagnosed with biopsy-proven GCA, periodically followed at the rheumatology outpatient clinic of Hospital Xeral-Calde, Lugo (Spain), who had ended steroid therapy and had at least 3 years of followup were assessed for the presence of atherosclerosis by determination of the carotid intima-media thickness (IMT) and carotid plaques using high-resolution B-mode ultrasound. Forty matched controls were also studied.

RESULTS

GCA patients exhibited less carotid artery IMT than did matched controls (mean +/- SD 1.01 +/- 0.16 mm versus 1.13 +/- 0.20 mm; P = 0.005; difference in means 0.12, 95% confidence interval 0.04-0.20). Patients who required steroid therapy for >2 years had greater mean +/- SD carotid IMT (1.04 +/- 0.17 mm versus 0.95 +/- 0.15 mm) but the difference was not statistically significant (P = 0.10). A positive correlation between age at the time of the study and the carotid artery IMT in GCA patients was observed (r = 0.673, P < 0.001). However, adjusting for age, sex, and classic atherosclerosis risk factors, no significant correlation between carotid IMT and the routine laboratory markers of inflammation assessed at the time of disease diagnosis, disease duration, or cumulative prednisone dose was found.

CONCLUSION

The present study demonstrates that atherosclerotic macrovascular disease is not increased in patients with GCA.

Importance of measuring the time course of flow-mediated dilatation in humans

Flow-mediated dilatation (FMD) is widely used to describe conduit artery endothelial function. The traditional approaches to FMD calculation assess diameter change at arbitrary time points after occluding cuff deflation. The aim of this study was to examine the time course of brachial artery FMD after a 5-minute period of forearm ischemia in 12 young, 12 fitness matched older and 12 older untrained subjects. Edge-detection and wall tracking of high resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, were used to calculate brachial artery diameter, blood flow, and shear rate continuously across the cardiac cycle after forearm ischemia. FMD was significantly higher in young healthy subjects (7.8+/-3.2%) compared with sedentary older subjects (5.2+/-2.8%, P<0.05) but not trained older subjects (6.4+/-2.3%). Time to peak diameter differed between young (50+/-11 seconds) and both older groups (trained; 80+/-21, P<0.001; sedentary: 83+/-36 seconds, P<0.001). A large proportion (>42%) of true peak diameters fell outside the time frames typically used to assess FMD in the literature. When calculated according to the commonly used approach, ie, 60 s after cuff deflation, FMD was significantly lower compared with true peak FMD in all groups (P<0.001), and no differences were evident between the groups. The time course of FMD differs significantly between young and older subjects. Studies assuming that peak dilation occurs at an arbitrary time point, or within limited time windows, may draw misleading conclusions regarding differences between groups. More sophisticated approaches to measurement of FMD are required if it is to be considered a valid biomarker of vascular disease.

Lowering serum urate does not improve endothelial function in patients with type 2 diabetes

AIMS/HYPOTHESIS

Endothelial dysfunction contributes to excess cardiovascular risk in patients with type 2 diabetes. There is strong evidence of an association between high serum uric acid concentrations and endothelial dysfunction, and uric acid has been proposed as an independent cardiovascular risk factor in type 2 diabetes. We hypothesised that lowering of uric acid concentrations might allow restoration of endothelial function in this high-risk group.

METHODS

Intravenous urate oxidase (1.5 mg) was administered to ten patients with type 2 diabetes and ten healthy participants in a two-way, randomised, placebo-controlled, crossover study. Forearm blood flow responses to intra-brachial acetylcholine, sodium nitroprusside and N(G)-monomethyl-L-arginine (L-NMMA) were measured using venous occlusion plethysmography. The augmentation index (AIx) was determined by pulse wave analysis as a measure of large arterial stiffness.

RESULTS

Acetylcholine and L-NMMA evoked lesser responses in patients with type 2 diabetes than in healthy participants. Baseline AIx was higher in patients with type 2 diabetes (mean +/- SD: 13.1 +/- 6.9%) than in healthy participants (2.0 +/- 5.1%; p = 0.006). Urate oxidase lowered serum uric acid concentrations by 64 +/- 11% (p < 0.001), but this had no effect on forearm blood flow responses or AIx in either group.

CONCLUSIONS/INTERPRETATION

Substantial short-term lowering of uric acid did not have a direct vascular effect, suggesting that, on its own, this might not be an effective strategy for restoring endothelial function in patients with type 2 diabetes.

Intracellular adhesion molecule concentrations in women who smoke during pregnancy

OBJECTIVE

Smoking and endothelial dysfunction are associated with adverse pregnancy outcomes. The effect of smoking on vascular endothelium during pregnancy has not been well studied. Our objectives were to determine if smoking has an impact on endothelial function in pregnancy by comparing markers of endothelial function and to evaluate the contribution from different cellular sources.

METHODS

We measured markers of endothelial function in a prospective cohort of 198 primiparous women who had 325 plasma samples obtained throughout pregnancy. Samples were assayed for intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin. Smoking status was determined by serum cotinine concentration. Analyses of adhesion molecules were performed for 4 gestational age intervals by using Mann-Whitney and Kruskal-Wallis tests. Gene expression for ICAM-1 was determined by real-time polymerase chain reaction from placental biopsies. A human umbilical vein endothelial cell (HUVEC) culture model was utilized to evaluate the effect of cotinine on endothelial cell production of ICAM-1.

RESULTS

ICAM-1 is increased, VCAM-1 was not different, and E-selectin was decreased among smokers at various times during pregnancy. Placental production of ICAM-1 was decreased in women who smoked (P = .02) as measured by real-time polymerase chain reaction. Human umbilical vein endothelial cells production of ICAM-1 increased with heavy concentrations of cotinine exposure (P < .01).

CONCLUSION

Smoking during pregnancy is associated with vascular perturbations, as evidenced by increased concentrations of serum ICAM-1. It appears unlikely that the source of the increased ICAM-1 is the placenta. The endothelium most likely contributes to increased maternal ICAM-1 in heavy smokers, but a leukocyte source cannot be ruled out.

LEVEL OF EVIDENCE

II-2.

Endothelial dysfunction in vivo is related to monocyte resistin mRNA expression

BACKGROUND

Resistin could be the linkage between the adipose tissue and the insulin resistance. In humans, the role of resistin on metabolic and vascular homeostasis is not well defined. The aim of this study was to investigate the possible association between resistin expression and insulin resistance.

METHODS AND RESULTS

We evaluated the relationship between monocyte expression of mRNA and anthropometric and metabolic parameters of insulin resistance. We focused on the potential role of resistin on endothelial function. Thirty-nine patients with metabolic syndrome (MS) and clinically free from cardiovascular disease, and 15 healthy subjects were included in this study. All subjects underwent clinical examination, assessment of haematochemical parameters, bioimpedentiometry, measurement of monocyte resistin mRNA and of brachial-artery flow-mediated vasodilation (FMV). Patients with MS showed higher levels of interleukin-6 (IL; 2.1 +/- 1.2 vs. 1.2 +/- 0.9 pg/mL, P < 0.05) and reduced FMV (5.4 +/- 3.9 vs. 8.3 +/- 3.1%, P < 0.05). The subjects were divided into two groups: (i) subjects with high expression mRNA resistin levels and (ii) subjects with low or not detectable; Group 1 was younger (50 +/- 13 vs. 59 +/- 11 years, P = 0.01), showed higher IL-6 values (2.3 +/- 1.2 vs. 1.6 +/- 1.2, P = 0.03) and lower values of FMV (4.3 +/- 2.8 vs. 7.4 +/- 3.9%, P = 0.003). With univariate analysis monocyte mRNA showed a significant positive correlation with waist circumference (r = 0.27, P < 0.05) and IL-6 (r = 0.26, P < 0.05) and a negative correlation with FMV (r = -0.38, P < 0.005). With multivariate regression analysis brachial-artery diameter, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, IL-6 and RNAm resistin expression were independent predictors of reduced FMV.

CONCLUSIONS

mRNA resistin negatively influences FMV, and is a possible in vivo index of endothelial dysfunction.

Childhood origins of arterial disease

PURPOSE OF REVIEW

The present article reviews the importance of classical and novel risk factors that present in childhood, track into adult life and contribute to arterial disease. The value of noninvasive techniques that can assist in characterization of preclinical atherosclerotic changes as intermediate phenotypes is also discussed.

RECENT FINDINGS

Noninvasive functional and structural techniques are now available and provide the opportunity to characterize early arterial disease long before cardiovascular complications present. By using these techniques, it has been possible to quantify the impact of conventional and novel cardiovascular risk factors seen in childhood on the development of preclinical atherosclerotic changes. Scientific interest has recently widened to include not only study of mechanisms and biomarkers of injury but also mechanisms that promote vascular repair. In this new field, characterization of endothelial progenitor cells has presented new opportunities for cardiovascular research.

SUMMARY

Atherosclerosis begins in early life. Primary prevention strategies for adult cardiovascular disease beginning in childhood have great potential as the disease process is most reversible at this stage. Several guidelines have recently been published for screening and implementation of appropriate therapeutic choices in early life.

High prevalence of subclinical atherosclerosis in psoriatic arthritis patients without clinically evident cardiovascular disease or classic atherosclerosis risk factors

OBJECTIVE

To assess the presence of subclinical atherosclerosis in patients with psoriatic arthritis (PsA) without clinically evident atherosclerosis or its complications, and to assess whether demographic or clinical factors affect the development of atherosclerotic disease in a series of patients with PsA attended to in a community hospital.

METHODS

Fifty-nine patients with PsA who fulfilled the Moll and Wright criteria were recruited from Hospital Xeral-Calde (Lugo, Spain). Patients seen during the period of recruitment who had classic cardiovascular risk factors or had experienced cardiovascular or cerebrovascular events were excluded. Fifty-nine healthy matched controls were also studied. Carotid artery intima-media thickness (IMT) and carotid plaques were measured in the right common carotid artery. The study was performed using high-resolution B-mode ultrasound.

RESULTS

Patients with PsA exhibited greater carotid artery IMT than did matched controls (mean +/- SD 0.699 +/- 0.165 mm versus 0.643 +/- 0.111 mm; P = 0.031; difference of means 0.056; 95% confidence interval 0.005-0.108). Adjusted for age, the carotid IMT was correlated with age at the time of PsA diagnosis (partial correlation coefficient [r] = -0.264, P = 0.04), disease duration (r = 0.264, P = 0.04), total cholesterol (r = 0.233, P = 0.01), and low-density lipoprotein cholesterol (r = 0.243, P = 0.01).

CONCLUSION

The present study demonstrates that patients with PsA without cardiovascular risk factors or clinically evident cardiovascular disease have a high prevalence of macrovascular disease in the form of increased carotid artery IMT compared with ethnically matched controls.

Effects of prostaglandin E1alpha cyclodextrin [corrected] treatment on endothelial dysfunction in patients with systemic sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is characterized by an altered nitric oxide (NO): endothelin I ratio and by endothelial dysfunction.

AIMS

To verify the effects of prostaglandin E1 (PGE1) alpha-cyclodestrin treatment on endothelial function, quantified as flow-mediated dilation (FMD) of the radial artery.

METHODS

In 16 women with SSc (age 57 +/- 2.7 years, means +/- SE) in whom a diagnosis of SSc had been made several years earlier (7.1 +/- 1.2 years), FMD was evaluated by an echotracking technique on the radial artery, using trinitroglycerin vasodilation as a non-endothelial measure of the vessel's ability to increase its diameter maximally. FMD was evaluated after 4 months washout period and after 4 months cyclic infusion of PGE1 alpha-cyclodestrin. Expired NO was measured at the same time.

RESULTS

PGE1 alpha-cyclodestrin cyclic infusions did not modify systolic and diastolic blood pressure, heart rate or trinitroglycerin radial artery vasodilation. On the other hand, it induced a marked and significant increase in FMD of the radial artery, which was also accompanied by an increase in blood flow and expired NO.

CONCLUSIONS

Endothelial dysfunction and reduced FMD associated with SSc are improved by cyclic treatment with PGE1 alpha-cyclodestrin. This effect occurs together with a concomitant increase in expired NO, suggesting its direct positive influence on endothelial function. It may also partly explain the clinical beneficial effect of the drug in SSc.

Fibrinolytic markers and vasodilatory capacity following acute exercise among men of differing training status

We evaluated the effect of differing physical activity patterns on fibrinolysis and vasodilatory capacity using a cross-sectional design with 16 endurance-trained (ET) (mean+/-SE) (28+/-6 years), 14 resistance-trained (RT) (28+/-7 years), and 10 untrained (UT) (26+/-7 years) men. t-PA and PAI-1 activity and t-PA antigen were measured before and after a maximal treadmill test (VO2peak). Vasodilatory capacity was assessed using strain-gauge plethysmography on the forearm following reactive hyperemia (RH) before and after the treadmill test. The ET group had a smaller body mass index (BMI) (22.8+/-0.5 ET, 26.4+/-0.4 RT, 25.1+/-0.8 UT kg m(-2)) (P<0.05) and a greater VO2peak (57+/-1 ET, 42+/-2 RT, 45+/-2 UT mL min(-1) kg(-1)) (P<0.05). Peak vasodilatory capacity (29.7+/-2 ET, 32.0+/-2 RT, 27.4+/-2 UT mL min(-1) 100 mL of tissue) was similar between groups before and after exercise. Area under the curve for forearm blood flow was greater following acute exercise (212 vs. 122, P<0.05), again with no differences between groups. t-PA activity and antigen increased following maximal exercise in all groups (P<0.0001), with no group differences. PAI-1 activity decreased the least in RT after exercise (70% decrease vs. 86% ET and 82% UT; P<0.05). The change in t-PA activity with exercise was not related to exercise-induced change in overall vasodilatory capacity. These findings demonstrate that in healthy young men different physical activity patterns do not appear to impact the exercise-induced changes in fibrinolysis or vasodilatory capacity.

Impaired vascular function in patients with Fontan circulation

BACKGROUND

This study was performed to evaluate the endothelial function in Fontan patients, and to investigate the associated factors which influence the endothelial function in these patients.

METHODS

Flow mediated dilatation (FMD) and nitroglycerin induced dilatation (NG) of the brachial artery, and intima media thickness (IMT) of common carotid artery (CCA) were measured in nonselected Fontan patients (n=44, age 5 to 29 years, median 14 years, 18 females) by means of high-resolution ultrasound according to the standard protocols. The results were compared to age and sex matched controls (n=25, age 5 to 27 years, median 13 years, 10 females).

RESULTS

Fontan patients presented significantly reduced FMD and NG compared with controls (FMD; 6.5+/-2.4 vs. 11.1+/-1.4%, p<0.001, NG; 13.3+/-5.2 vs. 19.4+/-6.2%; p=0.035). Twenty two percent of Fontan patients presented pure endothelial dysfunction, and 34% of patients presented combined endothelial and smooth muscle dysfunction. Although there was no correlation between FMD and IMT, Fontan patients presented increased carotid IMT (0.44+/-0.07 vs. 0.38+/-0.06 mm, p=0.008). In multivariate analysis, duration of exposure to chronic hypoxia was inversely correlated with FMD (p=0.117, hazards ratio=1.294, 95% confidence interval=0.938-1.786). There was higher FMD in patients receiving angiotensin-converting enzyme inhibitors (ACEi) compared with those not receiving ACEi (7.0+/-2.5 vs. 5.5+/-2.2%, p=0.069).

CONCLUSIONS

Endothelial dysfunction is more prevalent in Fontan patients compared with healthy controls, and the previous hypoxia is an independent factor. Although it is not statistically significant, those patients on treatment with ACEi seem to have better endothelial function.