endothelin-1 and Arteriosclerosis

Retinal vein occlusion (RVO) is a common vascular disease of retina; however, the pathomechanism leading to RVO is not yet clear. In general, increasing age, hypertension, arteriosclerosis, diabetes mellitus, dyslipidemia, cardiovascular disorder, and cerebral stroke are systemic risk factors of RVO. However, RVO often occur in the unilateral eye and sometimes develop in young subjects who have no arteriosclerosis. In addition, RVO show different variations on the degrees of severity; some RVO are resolved without any treatment and others develop vision-threatening complications such as macular edema, combined retinal artery occlusion, vitreous hemorrhage, and glaucoma. Clinical conditions leading to RVO are still open to question. In this review, we discuss how to treat RVO in practice by presenting some RVO cases. We also deliver possible pathomechanisms of RVO through our clinical experience and animal experiments.

Topics: Animals; Arteriosclerosis; Diabetes Complications; Dyslipidemias; Endothelin-1; Humans; Hypertension; Retina; Retinal Vein Occlusion; Risk Factors; Stroke; Veins

Endothelin-1 (ET-1) is a vasoconstrictor, proinflammatory and proliferative endothelial cell-derived peptide that is of significant importance in the regulation of vascular function. It is involved in the development of endothelial dysfunction including important interactions with nitric oxide. The expression and functional effects of ET-1 and its receptors are markedly altered during development of cardiovascular disease. Increased production of ET-1 and its receptors mediate many pathophysiological events contributing to the development of atherosclerosis and vascular complications in diabetes mellitus. The present review focuses on the pathophysiological role of ET-1 and the potential importance of ET receptors as a therapeutic target for treatment of these conditions.

Topics: Animals; Arteriosclerosis; Diabetes Mellitus, Type 2; Endothelin-1; Endothelium, Vascular; Humans; Nitric Oxide; Receptors, Endothelin; Vasoconstriction

Topics: Animals; Arteriosclerosis; Asthma; Chymases; Endothelin-1; Glomerulonephritis; Humans; Muscle Contraction; Peptide Fragments; Serine Endopeptidases

Topics: Animals; Arteriosclerosis; Biomarkers; Bosentan; Diagnostic Techniques, Endocrine; Drug Design; Endothelin Receptor Antagonists; Endothelin-1; Heart Failure; Humans; Hypertension; Hypertension, Pulmonary; Receptors, Endothelin; Reference Values; Sulfonamides

Topics: Angiotensin II; Arteriosclerosis; Cardiovascular Diseases; Cell Adhesion Molecules; Coagulants; Diabetes Mellitus; Endothelin-1; Endothelium, Vascular; Female; Humans; Pre-Eclampsia; Pregnancy; Vasoconstrictor Agents; Vasodilator Agents

Topics: Animals; Arteriosclerosis; Cell Division; Dansyl Compounds; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Humans; Muscle, Smooth, Vascular; Neovascularization, Pathologic; Peptides, Cyclic; Receptor, Endothelin A; Receptor, Endothelin B; Vasoconstriction

Since endothelial dysfunction may significantly contribute to the pathophysiology of hypertension and its complications, its modification seems to be a very attractive means to favourably affect the development of atherosclerosis and cardiovascular events in hypertensive patients. However, not all antihypertensive drugs consistently improve endothelial dysfunction. While first-generation beta-blockers showed contrasting or null effects on endothelial function, newer beta-blockers of the third generation, such as carvedilol and nebivolol, seem to be provided with specific endothelium-mediated vasodilating effects. Calcium channel blockers are generally able to increase endothelium-dependent vasodilation in several vascular beds, in patients with essential hypertension, probably through multiple mechanisms. Most studies have shown thatACE inhibitors favourably affect endothelial function mainly in the subcutaneous, epicardial and renal circulation, not only by inhibiting the effects of angiotensin II on the endothelium, but also by enhancing bradykinin-induced vasodilation, probably a hyperpolarization-related effect. On the other hand, discordant evidence is available about the effects of angiotensin II receptor type I blockers on endothelial function in patients with essential hypertension, atherosclerosis or diabetes.There are data suggesting that an increased activity of the endothelin- I system may play a role in the blunted endothelium-dependent vasorelaxation of hypertensive patients, an effect that could be contrasted by the use of endothelin-I receptor antagonists. However, to date no substantial clinical efficacy of endothelin-I receptor blockers has been shown in patients with essential hypertension. Finally, other possibly useful compounds in restoring impaired endothelial function in hypertension are some antioxidant agents such as vitamin C, folic acid, the cofactor tetrahydrobiopterin (BH4), L-arginine and the drugs of the statin class.

Topics: Animals; Antihypertensive Agents; Arteriosclerosis; Constriction, Pathologic; Endothelin-1; Endothelium, Vascular; Humans; Hypertension; Vasodilation

An elevated vascular superoxide anion formation has been implicated in the initiation and progression of hypertension and atherosclerosis. In this review, we would like to discuss the generation of superoxide anions by an NADPH oxidase complex in vascular cells. Special focus is on the induction of endothelial NADPH oxidase by proatherosclerotic stimuli. We propose a proatherosclerotic vicious cycle of increased NADPH oxidase-dependent superoxide anion formation, augmented generation and uptake of oxidatively modified low-density lipoprotein, and further potentiation of oxidative stress by oxidized low-density lipoprotein itself, angiotensin II, and endothelin-1 in endothelial cells. Furthermore, novel homologues of NADPH oxidase subunit gp91(phox) are summarized. Future directions of research for a better understanding of the role of NADPH oxidase in the pathogenesis of atherosclerosis and clinical implications are discussed.

Topics: Animals; Arteriosclerosis; Cell Membrane; Endothelial Cells; Endothelin-1; Endothelium, Vascular; Humans; Lipoproteins, LDL; Membrane Glycoproteins; Models, Biological; NADPH Oxidase 2; NADPH Oxidases; Oxidative Stress; Oxygen; Protein Isoforms; Structure-Activity Relationship

Atherosclerosis is a major risk factor for both myocardial infarction and stroke. A key aspect of this disease is the imbalance of vasoactive factors. In this concise review, we focus on the role of endothelin-1 in the atherosclerotic process and other vasculopathies. Previously, we have demonstrated that there is a correlation between the expression of endothelin and the underlying atherosclerotic lesion. Immunoreactivity was observed for both ET-1 and ECE-1 in endothelial cells, smooth muscle cells, and macrophages within lesions. Endothelin's role in atherosclerosis must extend from its varying physiological activities, including vasoconstriction, mitogenesis, neutrophil adhesion, and platelet aggregation, and hypertrophy, as well as its propensity to induce the formation of reactive oxygen species. We also discuss regulation of endothelin by angiotensin II, reactive oxygen species, thrombin, aging, and LDL in the cardiovascular system. Finally, we demonstrate the role of endothelin in pulmonary hypertension and transplant associated vasculopathy.

Topics: Animals; Arteriosclerosis; Aspartic Acid Endopeptidases; Endothelin-1; Endothelin-Converting Enzymes; Humans; Metalloendopeptidases; Vascular Diseases

The prevalence of type 2 diabetes globally is reaching epidemic proportions. Type 2 diabetes is strongly associated with increased risk of cardiovascular disease. Atherosclerosis is thought to arise as a result of a chronic inflammatory process within the arterial wall. Insulin resistance is central to the pathogenesis of type 2 diabetes and may contribute to atherogenesis, either directly or through associated risk factors. The peroxisome proliferator-activated receptor-gamma agonists, the thiazolidinediones, pioglitazone and rosiglitazone, are insulin sensitizing agents, that are licensed for the management of hyperglycaemia. Growing evidence supports an array of additional effects of thiazolidinedione therapy, both immunomodulatory and antiinflammatory, which may attenuate atherogenesis in type 2 diabetes.. Studies have shown that thiazolidinedione therapy may lead to risk factor modulation in type 2 diabetes. Thiazolidinediones treatment has been shown to reduce blood pressure, modify the atherogenic lipid profile associated with type 2 diabetes, reduce microalbuminuria and ameliorate the prothrombotic diathesis. Further evidence suggests that thiazolidinediones therapy inhibits the inflammatory processes which may be involved in atherosclerotic plaque initiation, propagation and destabilization.. Modification of insulin resistance by thiazolidinedione therapy in type 2 diabetes and the range of pleiotropic effects may not only impact on incident type 2 diabetes, but also on associated cardiovascular disease. Numerous large clinical endpoint studies are under way to investigate these issues.

Topics: Albuminuria; Arteriosclerosis; Blood Pressure; C-Reactive Protein; Carotid Arteries; Coronary Restenosis; Diabetes Mellitus, Type 2; Endothelin-1; Endothelium, Vascular; Humans; Hyperglycemia; Insulin Resistance; Lipoproteins; Matrix Metalloproteinases; Metformin; Muscle, Smooth, Vascular; Pioglitazone; Plasminogen Activator Inhibitor 1; PPAR gamma; Rosiglitazone; Thiazolidinediones

A healthy endothelium plays a central role in cardiovascular control. Therefore, endothelial dysfunction (ED), which is characterized by an imbalance between relaxing and contracting factors, procoagulant and anticoagulant substances, and between pro-inflammatory and anti-inflammatory mediators, may play a particularly significant role in the pathogenesis of atherosclerosis. ED is closely related to different risk factors of atherosclerosis, to their intensity and their duration. The involvement of risk factors in ED is also supported by results of intervention studies that showed regression of ED with treatment of risk factors. The common denominator whereby different risk factors cause ED is most probably increased oxidative stress and/or inflammation. ED promotes atherosclerosis and probably plays an important role in the development of thrombotic complications in the late stages of the disease. As ED is a key underlying factor in the atherosclerotic process, markers of endothelial abnormalities have been sought. Detection of ED is based on tests of endothelium-dependent vasomotion (dilation capability of peripheral and coronary arteries) and on circulating markers of endothelial function (endothelin-1, von Willebrand factor, tissue plasminogen activator, plasminogen activator inhibitor, adhesion molecules). Using these tests it is possible to follow the dose-response of harmful effects or risk factors, and the effects of preventive procedures on vessel wall function.

Topics: Arteriosclerosis; Cell Adhesion Molecules; Endothelin-1; Endothelium, Vascular; Humans; Nitric Oxide; Plasminogen Activator Inhibitor 1; Risk Factors; Tissue Plasminogen Activator; Vasodilation; von Willebrand Factor

Topics: Apolipoproteins; Arteriosclerosis; Cholesterol; Cholesterol, HDL; Clofibrate; Endothelin-1; Endothelium, Vascular; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypolipidemic Agents; NF-kappa B; Receptors, Cytoplasmic and Nuclear; Transcription Factors

Atherosclerotic vascular disease remains the single most prevalent cause of death and morbidity in the western world. Endothelin-1 (ET-1) is a potent vasoconstrictor peptide that also possesses mitogenic activity on many cell types, including vascular smooth muscle cells. Raised plasma and tissue levels of ET-1 have been described in atherosclerosis in animal models and in man, suggesting that this peptide plays a pathophysiological role in this condition. Two main ET-1 receptors have been cloned (ET(A) and ET(B)). Mixed ET(A/B) and receptor subtype selective antagonists are now available. Since ET-1 is generally believed to be a 'pathophysiological peptide', we discuss the therapeutic potential of ET-1 antagonists in atherosclerosis and consider whether, at certain sites in this process, ET-1 may play a beneficial role. In such situations ET antagonism may be undesirable.

Topics: Animals; Arteriosclerosis; Endothelin Receptor Antagonists; Endothelin-1; Humans; Muscle, Smooth, Vascular; Receptor, Endothelin A

The endothelins are synthesized in vascular endothelial and smooth muscle cells, as well as in neural, renal, pulmonal, and inflammatory cells. These peptides are converted by endothelin-converting enzymes (ECE-1 and -2) from 'big endothelins' originating from large preproendothelin peptides cleaved by endopeptidases. Endothelin (ET)-1 has major influence on the function and structure of the vasculature as it favors vasoconstriction and cell proliferation through activation of specific ET(A) and ET(B) receptors on vascular smooth muscle cells. In contrast, ET(B )receptors on endothelial cells cause vasodilation via release of nitric oxide (NO) and prostacyclin. Additionally, ET(B) receptors in the lung are a major pathway for the clearance of ET-1 from plasma. Indeed, ET-1 contributes to the pathogenesis of important disorders as arterial hypertension, atherosclerosis, and heart failure. In patients with atherosclerotic vascular disease (as well as in many other disease states), ET-1 levels are elevated and correlate with the number of involved sites. In patients with acute myocardial infarction, they correlate with 1-year prognosis. ET receptor antagonists have been widely studied in experimental models of cardiovascular disease. In arterial hypertension, they prevent vascular and myocardial hypertrophy. Experimentally, ET receptor blockade also prevents endothelial dysfunction and structural vascular changes in atherosclerosis due to hypercholesterolemia. In experimental myocardial ischemia, treatment with an ET receptor antagonist reduced infarct size and prevented left ventricular remodeling after myocardial infarction. Most impressively, treatment with the selective ET(A) receptor antagonist BQ123 significantly improved survival in an experimental model of heart failure. In many clinical conditions, such as congestive heart failure, both mixed ET(A/B )as well as selective ET(A) receptor antagonism ameliorates the clinical status of patients, i.e. symptoms and hemodynamics. A randomized clinical trial showed that a mixed ET(A/B) receptor antagonist effectively lowered arterial blood pressure in patients with arterial hypertension. In patients with primary pulmonary hypertension or pulmonary hypertension related to scleroderma, treatment with a mixed ET(A/B) receptor antagonist resulted in an improvement in exercise capacity. ET receptor blockers thus hold the potential to improve the outcome in patients with various cardiovascular disorders. Randomize

Topics: Animals; Arteriosclerosis; Cardiovascular Diseases; Endothelin Receptor Antagonists; Endothelin-1; Heart Failure; Humans; Hypertension, Pulmonary; Myocardial Infarction; Renal Insufficiency

Endothelial dysfunction is an early event in atherosclerosis and could be considered a response to the injury induced by major risk factors. There is evidence that endothelial dysfunction is intimately involved in the onset and the progression of cardiovascular disease through abnormalities in the production, release or degradation of endothelium-derived factors, mainly nitric oxide and endothelin 1. Several reports have shown that drugs of the statin class could have multiple beneficial effects related to endothelium-mediated vasoactive, antithrombotic, antiproliferative and anti-inflammatory actions. Thus, the question arises of whether endothelial cells are the main target of statin therapy, in the setting of both hypercholesterolemia and normocholesterolemia. Experimental and clinical studies are reported that could support this hypothesis.

Topics: Animals; Anticholesteremic Agents; Arteriosclerosis; Endothelin-1; Endothelium, Vascular; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Nitric Oxide

Initial pharmacologic therapy for hypertension is low-dose thiazide diuretics, beta-blockers, and ACE inhibitors. Increasing data have confirmed that ACE inhibitors have specific benefit in patients with diabetes, atherosclerosis, left ventricular dysfunction, and renal insufficiency. CCBs are alternative agents for ISH in the elderly and appear to decrease stroke with perhaps less protection against progression of renal insufficiency and proteinuria, CAD mortality and new onset heart failure versus other initial agents, especially ACE inhibitors. ARBs are well tolerated and effective blood pressure lowering agents but have not been confirmed as effective as ACE inhibitors for reducing renal progression, clinical events, or mortality from heart failure. Effective pharmacologic antihypertensive therapy may avoid disabling and undetected cerebrovascular disease, cognitive dysfunction, and disturbing symptoms of elevated blood pressure. Vasopeptidase inhibitor, such as omapatrilat, and endothelin-1 antagonist, such as bosentan, may become future agents approved for the reduction of morbidity and mortality with hypertension. The ALLHAT trial continues to examine the potential benefits and harms of amlodipine versus chlorthalidone and lisinopril in a diverse high-risk population. Based on ALLHAT data, however, doxazosin is no longer an acceptable initial pharmacological agent. Intensive pharmacologic treatment with blood pressure lowering to less than 130/85 mm Hg is recommended with diabetes, renal insufficiency, and heart failure with additional goal of less than 125/75 mm Hg with renal failure and proteinuria greater than 1 g/24 h, based on multiple outcome studies.

Topics: Adrenergic beta-Antagonists; Aged; Aged, 80 and over; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Arteriosclerosis; Bosentan; Bradykinin; Calcium Channel Blockers; Diabetes Complications; Diuretics; Drug Therapy, Combination; Endothelin-1; Female; Heart Failure; Humans; Hypertension; Male; Middle Aged; Patient Compliance; Pyridines; Quality of Life; Renal Insufficiency; Renin-Angiotensin System; Risk Factors; Sulfonamides; Systole; Thiazepines; Treatment Outcome

Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide and regulator of blood flow that plays an important role in blood pressure (BP) elevation in some models of experimental hypertension such as DOCA-salt rat, DOCA-salt-treated spontaneously hypertensive rats (SHR), stroke-prone SHR, Dahl salt-sensitive rats, angiotensin II-infused rats, and one-kidney, one-clip Goldblatt rats, but not in SHR, two-kidney, one-clip hypertensive rats, transgenic (mREN2)27 rats, or Nomega-nitro-L-arginine methyl ester chronically treated rats. In those models of hypertension in which ET-1 plays a vasoconstrictor role, ET-1 was shown to be overexpressed in the vessel walls, or BP has been lowered by administration of ET(A/B)- and ET(A)-selective receptor antagonists. In these experimental models, endothelin receptor antagonists also regressed vascular growth and inflammation, and improved endothelial dysfunction. Hypertensive rats treated with endothelin antagonists were protected from stroke and renal injury. In hypertensive rats without generalized vascular overproduction of ET-1, expression of ET-1 was often enhanced in intramyocardial coronary arteries, suggesting a role of ET in myocardial ischemia in hypertension. Moderate-to-severe hypertensive patients presented enhanced expression of pre-proET-1 mRNA in the endothelium of subcutaneous resistance arteries, suggesting that this stage of hypertension may respond particularly well to endothelin antagonism. In some hypertensive patients, exaggerated vascular responses to ET-1 were found. Hypertensive patients with coronary artery disease have increased arterial expression of ET-1. Increased plasma levels of immunoreactive ET have been described in African Americans. ET-1 plays an important role in atherosclerosis, for which hypertension is an important risk factor, and in ischemic heart disease and stroke. Endothelin-1 may also be involved in other forms of vascular disease, including pulmonary hypertension, after angioplasty restenosis, after allograft vasculopathy, and vasculitis. Thus, ET-1 may participate in vascular damage in cardiovascular disease and in BP elevation in experimental models and in human hypertension. Endothelin antagonists could become effective disease-modifying agents in different forms of cardiovascular disease.

Topics: Animals; Arteriosclerosis; Blood Vessels; Endothelin-1; Humans; Hypertension; Vascular Diseases

Our understanding of the role of the endothelin system in human cardiovascular physiology and pathophysiology has evolved very rapidly since the initial description of its constituent parts in 1988. Endothelin-1 (ET-1) is the predominant endothelin isoform in the human cardiovascular system and has potent vasoconstrictor, mitogenic and antinatriuretic properties which have implicated it in the pathophysiology of a number of cardiovascular diseases. The effects of ET-1 have been shown to be mediated by 2 principal endothelin receptor subtypes: ET(A) and ET(B). The development of a range of peptidic and nonpeptidic endothelin receptor antagonists represents an exciting breakthrough in human cardiovascular therapeutics. Two main classes of endothelin receptor antagonist have been developed for possible human therapeutic use: ET(A)-selective and nonselective antagonists. Extensive laboratory and clinical research with these agents has highlighted their promise in various cardiovascular diseases. Randomised, placebo-controlled clinical trials have yielded very encouraging results in patients with hypertension and chronic heart failure with more preliminary data suggesting a possible role in the treatment and prevention of atherosclerosis and stroke. Much more research is needed, however, before endothelin receptor antagonists can be considered for clinical use.

Topics: Aged; Animal Population Groups; Animals; Arteriosclerosis; Cardiovascular Diseases; Drugs, Investigational; Endothelin Receptor Antagonists; Endothelin-1; Heart Failure; Humans; Hypertension, Pulmonary; Receptors, Endothelin; Stroke

The endothelium plays a crucial role in the regulation of cardiovascular structure and function by releasing several mediators in response to biochemical and physical stimuli. These mediators are grouped into two classes: (1) endothelium-derived constricting factors (EDCFs) and (2) endothelium-derived relaxing factors (EDRFs), the roles of which are considered to be detrimental and beneficial, respectively. Endothelin-1 (ET-1) and nitric oxide (NO) are the prototypes of EDCFs and EDRFs, respectively, and their effects on the cardiovascular system have been studied in depth. Numerous conditions characterized by an impaired availability of NO have been found to be associated with enhanced synthesis of ET-1, and vice versa, thereby suggesting that these two factors have a reciprocal regulation. Experimental studies have provided evidence that ET-1 may exert a bidirectional effect by either enhancing NO production via ETB receptors located in endothelial cells or blunting it via ETA receptors prevalently located in the vascular smooth muscle cells. Conversely, NO was found to inhibit ET-1 synthesis in different cell types. In vitro and in vivo studies have started to unravel the molecular mechanisms involved in this complex interaction. It has been clarified that several factors affect in opposite directions the transcription of preproET-1 and NO-synthase genes, nuclear factor-KB and peroxisome proliferator-activated receptors playing a key role in these regulatory mechanisms. ET-1 and NO interplay seems to have a great relevance in the physiological regulation of vascular tone and blood pressure, as well as in vascular remodeling. Moreover, an imbalance between ET-1 and NO systems may underly the mechanisms involved in the pathogenesis of systemic and pulmonary hypertension and atherosclerosis.

Topics: Animals; Arteriosclerosis; Cardiovascular Physiological Phenomena; Endothelin-1; Endothelium, Vascular; Gene Expression Regulation; Humans; Hypertension, Pulmonary; Models, Biological; NF-kappa B; Nitric Oxide; Protein Precursors; Receptor, Endothelin A; Receptors, Cytoplasmic and Nuclear; Receptors, Endothelin; Signal Transduction; Transcription Factors

Endothelial cells are strategically located between the circulating blood and the vascular smooth muscle. These cells are involved in regulating the functions of vascular smooth muscle and circulating blood cells by releasing numerous vasoactive substances. Important endothelium-delivered vasodilators include prostacyclin, bradykinin, nitric oxide and endothelium-derived hyperpolarising factor. Nitric oxide is also important in inhibiting cellular growth and migration, and acts in concert with prostacyclin to exert potent antiatherogenic and thromboresistant effects by preventing platelet aggregation and cell adhesion. These effects are counterbalanced by vasoconstrictors such as angiotensin II and endothelin-1, which exert prothrombotic inflammatory and growth-promoting properties. Cardiovascular risk factors give rise to cardiovascular disease by causing endothelial dysfunction. Consequently, modern therapeutic strategies focus on preserving or restoring endothelial integrity. Calcium antagonists counteract the effects of angiotensin II and endothelin-1 at the level of vascular smooth muscle by reducing Ca2+ inflow and facilitating the vasodilator effects of nitric oxide. In addition to their role in inhibiting the renin-angiotensin system, angiotensin-converting enzyme (ACE) inhibitors raise the activity of bradykinin, thereby leading to an increase in nitric oxide release. In patients with cardiovascular risk, chronic ACE inhibition improves endothelial function. This may explain why patients treated with ACE inhibitors experience a greater cardiovascular benefit than is attributable to the decrease in blood pressure. Recently developed neutral endopeptidase inhibitors, particularly in combination with ACE inhibitors, induce potent antihypertensive effects. These effects are due partly to decreased breakdown of natriuretic peptides but also as a result of the inhibition of endothelin-1 production. Experimental studies suggest that endothelin-1 antagonists are effective in lowering blood pressure in hypertensives, and also exert beneficial clinical and haemodynamic effects in patients with congestive heart failure. Further clinical studies are under way to determine whether restoration of endothelial function has clinical benefits for patients with cardiovascular disease.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Arteriosclerosis; Clinical Trials as Topic; Cytokines; Endothelin-1; Endothelium, Vascular; Humans; Losartan; Mice; Mice, Knockout; Nitric Oxide Synthase; Renin-Angiotensin System

Increased evidence has shown that endothelin-1 (ET-1) derived from the arterial cells is involved in the development of atherosclerosis. ET-1 and ET receptors are upregulated in both human and experimental animal atherosclerotic lesions. Plasma ET-1 levels are significantly elevated in hypercholestolemic subjects and cholesterol-fed animals. We hypothesized that plasma lipoproteins such as LDL and HDL retained in the arterial wall can affect ET-1 production and secretion, thereby sustaining vascular functions. Using a two-chamber culture system, we have demonstrated that endothelial cells (ECs) show a polar secretion of ET-1; the majority of ET-1 are secreted toward the basal side of the vessels. Furthermore, we found that LDL enhances whereas HDL inhibits the ET-1 secretion from ECs in a polarized pattern. In order to demonstrate ET receptor distribution in the lesion, we recently studied both human and apoE-KO mice. Our study showed that there is an increased expression of ETB receptors in foamy macrophages in the lesions. More importantly, medial smooth muscle cells (SMCs) beneath the foam cell lesions exhibited a higher intensity of ETB receptor immunoreactivity than those located in foam cell-free areas. In such an area, ET-1 immunoreactivity is also increased. These results suggest that accumulation of foamy macrophages may modulate the shift of ET receptor subtypes from ETA to ETB in SMCs and an enhanced ET system mediated by ETB receptors may play a pivotal role in the progression of atherosclerosis. This notion has been further supported by a recent finding that administration of ET receptor antagonists resulted in a significant reduction of atherosclerosis in apoE-KO mice.

Topics: Animals; Arteriosclerosis; Endothelin Receptor Antagonists; Endothelin-1; Humans; Hypercholesterolemia; Mice; Receptors, Endothelin

Endothelial health is a key factor in normal cardiovascular homeostasis, and recent studies have revealed several important functions of the vascular endothelium that protect against atherothrombosis. These include control over arterial tone, coagulation, fibrinolysis, and vascular growth. Consequently, endothelial dysfunction has been implicated as an important event in the pathogenesis of atherosclerosis, coronary vasoconstriction, hypertension, and myocardial ischaemia. Therefore, there has been considerable research interest in diagnostic assays for the assessment of endothelium. This review outlines the current status of markers of endothelial dysfunction, particularly those related to vasomotor control, as well as circulating markers of vascular health.

Topics: Adult; Aged; Arteriosclerosis; Biomarkers; Child; Confidence Intervals; Coronary Disease; Endothelin-1; Endothelium, Vascular; Humans; Hypercholesterolemia; Hypertension; Nitric Oxide; Plethysmography; Prognosis; Risk; Risk Factors; Tissue Plasminogen Activator; Tomography, Emission-Computed; Vasodilation; Vasomotor System; von Willebrand Factor

Endothelin (ET)-1, a potent vasoconstrictor peptide, is primarily released abluminally from endothelial cells and exerts its biological effect through the activation of specific ET receptors. Endothelin subtype A receptors (ET(A)) are involved in constriction and proliferation of vascular smooth muscle cells, whereas endothelin subtype B receptors (ET(B)) on endothelial cells mediate the formation of nitric oxide, which acts as vasodilator and inhibits platelet aggregation. Cardiovascular risk factors such as hypertension and aging, as well as hypercholesterolemia, which are precursors of atherosclerosis, and elevated ET-1 levels are found. The best approach to determine the contribution of endogenous ET to vascular structural and functional alterations can be achieved by chronic inhibition of ET receptors with ET receptor antagonists. Recent studies showed favourable effects of selective ET(A)-antagonists on vascular alterations in different experimental models of hypertension, hypercholesterolemia and atherosclerosis, suggesting that activation of the local ET system importantly contributes to endothelial dysfunction and vascular remodeling, mainly through ET(A) receptors. Chronic blockade of ET(A) receptors may be a new therapeutic approach for the treatment of atherosclerosis and its risk factors.

Topics: Aging; Arteriosclerosis; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Humans; Hypercholesterolemia; Hypertension; Receptors, Endothelin; Risk Factors; Vasoconstriction

Endothelins build a peptide family composed of three isoforms, each of them containing 21 amino acids. Endothelin-1 is the isoform mainly responsible for any cardiovascular action and therefore the sole scope of this review. Endothelin-1 is the most potent endogenous vasoconstrictor known; in addition it acts as a potent (co)mitogen. There is a substantial body of experimental evidence that endothelin-1 may contribute not only to sustained vasoconstriction, but also to remodeling within the cardiovascular system. Thus, with the help of endothelin receptor antagonists (available for a few years) the involvement of mainly ETA receptors in structural diseases such as heart failure, pulmonary hypertension, atherosclerosis, restenosis, systemic hypertension, and chronic renal failure has been shown. These data make endothelin receptor antagonists, and especially those selective for the ETA receptor, promising agents for the treatment of chronic cardiovascular diseases associated with remodeling. Currently several chemically distinct, orally available members of this novel class of therapeutic agents are under clinical investigation.

Topics: Animals; Arteriosclerosis; Cardiovascular Diseases; Cardiovascular System; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Heart Failure; Hemodynamics; Humans; Hypertension, Pulmonary; Rats; Vasoconstrictor Agents

Lipid and nonlipid mechanisms contribute to the beneficial effects of some statins on endothelial function, plaque stability and thrombus formation. The nonlipid effects of statins may contribute to alleviation of tissue ischemia and prevention of acute cardiovascular syndromes. Endothelial dysfunction is reversed by a statin and this beneficial property results, in part, from direct actions on the endothelial vasoactive factors, nitric oxide and endothelin-1. Some statins have been shown to inhibit production of proinflammatory cytokines that regulate many key functions of the vascular wall including monocyte adhesion, chemotaxis, and metalloproteinase secretion. Vascular smooth muscle cell synthetic capacity and viability is inhibited by lipophilic agents, whereas a hydrophilic agent does not interfere with this reparative response. Some statins may impede thrombogenesis by reduced activation of the extrinsic coagulation pathway, inhibition of platelet adhesion and aggregation, and improvement in the rheologic profile.

Topics: Anticholesteremic Agents; Arteriosclerosis; Blood Coagulation; Cytokines; Endothelin-1; Endothelium, Vascular; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Lovastatin; Nitric Oxide; Plasminogen Activator Inhibitor 1

An increasing body of evidence indicates that impairment of endothelial function is crucially involved in the pathogenesis of cardiovascular disease. Injury to the endothelium precipitates atherosclerosis by causing smooth-muscle cell migration and proliferation, induction of expression of growth factors, and impairment of plasma coagulation and endogenous fibrinolysis. Angiotensin-converting enzyme (ACE) inhibitors and calcium antagonists are widely used in patients with cardiovascular disease and have beneficial vascular effects beyond blood pressure control alone. Both exhibit a synergistic hemodynamic profile. Whereas calcium antagonists dilate large conduit and resistance arteries, ACE inhibitors inhibit the renin-angiotensin system (RAS) and reduce sympathetic outflow. Certain calcium antagonists, such as verapamil and diltiazem, reduce heart rate, whereas dihydropyridines tend to increase it. In the blood vessel wall, the local vascular effects of ACE inhibitors and calcium antagonists are complementary. ACE inhibitors diminish transformation of angiotensin I (Ang I) into angiotensin II (Ang II) and prevent degradation of bradykinin [which stimulates nitric oxide (NO) and prostacyclin formation]. Calcium antagonists inhibit the effects of Ang I and endothelin-1 (ET-1) at the level of vascular smooth muscle by reducing Ca2+ inflow and facilitating the vasodilator effects of NO. The resistance circulation is particularly dependent on extracellular Ca2+, thereby explaining why nifedipine and verapamil effectively inhibit ET-induced vasoconstriction in vitro and in vivo. In hypertension, ACE inhibitors and calcium antagonists markedly improve structural changes and increase the media/lumen ratio in resistance arteries. Long-term combination therapy with verapamil and trandolapril is particularly effective in reversing endothelial dysfunction in hypertensive animals. ACE inhibitors substantially reduce morbidity and mortality in patients with left ventricular dysfunction after myocardial infarction (MI). There is a strong trend indicating benefit with verapamil as well, but this is confined to patients with a normal left ventricular ejection fraction. Clinical studies have confirmed that calcium antagonists exhibit antiatherogenic properties. However, the clinical relevance of these findings has recently been disputed because short-acting dihydropyridines are reported to increase risk for MI. Because ACE inhibitors and calcium antagonists exhibit synerg

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Arteriosclerosis; Calcium Channel Blockers; Cardiovascular Diseases; Drug Therapy, Combination; Endothelin-1; Endothelium, Vascular; Humans; Muscle, Smooth, Vascular

Topics: Animals; Arteriosclerosis; Endothelin-1; Endothelin-2; Endothelin-3; Endothelins; Heart Failure; Humans; Hypertension, Pulmonary; Primary Prevention; Prognosis; Vasoconstriction

Coronary arteries are regulated by neuronal mechanisms, hormones and paracrine mediators. The importance of endothelium-dependent mechanisms has recently been recognized. The endothelium responds to mechanical and chemical signals from the blood by releasing mediators that modulate vascular tone and structure, platelet function, coagulation and monocyte adhesion. Important relaxing factors are nitric oxide, prostacyclin and a putative hyperpolarizing factor. Nitric oxide also inhibits smooth muscle proliferation and, together with prostacyclin, platelet function. Bradykinin-induced nitric oxide production is reduced by angiotensin-converting enzyme. Endothelin-1, thromboxane A2 and prostaglandin H2 are contracting factors. Thromboxane A2 and prostaglandin H2 activate platelets, while endothelin has no direct platelet effects, but causes smooth muscle proliferation. In hypercholestermia, endothelium-dependent relaxation is impaired and contraction as well as adhesion of monocytes and platelets enhanced. Pharmacological correction of hyperlipidemia by statins also improves or normalizes endothelial dysfunction in patients. Angiotensin-converting enzyme inhibitors have similar effects.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Anticholesteremic Agents; Arginine; Arteriosclerosis; Coronary Vessels; Endothelin-1; Endothelium, Vascular; Humans; Hyperlipidemias; Lipids; Lipoproteins, LDL; Lovastatin; Nitric Oxide; Swine

Atherosclerosis and its consequences account for most of morbidity and mortality in Western countries. Atherosclerosis develops over a period of decades and has a complex pathogenesis. It is a disease of the intima and primarily involves four cell types, i.e., endothelial and vascular smooth muscle cells, monocytes and platelets. In recent years, knowledge on the cellular and molecular mechanisms of these cells and their alterations by cardiovascular risk factors and in atherosclerosis has greatly expanded. In particular, it became clear that endothelial cells play a crucial role in the regulation of platelet function, coagulation as well as vascular tone and structure. Interestingly, endothelial dysfunction occurs early, particularly if cardiovascular risk factors such as hyperlipidemia, hypertension and diabetes are present. This could lead to adhesion of circulating platelets and monocytes and increased accumulation of lipids in the subintima as well as increased contraction, migration and proliferation of vascular smooth muscle cells. The fact that atherosclerosis develops only in certain, but not in other parts of the circulation, however, has rarely been considered. With the development of molecular biology techniques it became possible to clone differentially expressed genes in vessels with or without atherosclerosis; this in turn allows to better characterize the molecular and cellular mechanisms of the disease. The search for such candidate genes could set the basis for future genetic interventions. This therapeutic approach is likely to reach clinical importance particularly in monogenetic diseases (i.e., familial hypercholesterinemia), while its use in complex polygenetic diseases such as atherosclerosis is more difficult. Restenosis, however, may be accessible to gene therapy earlier on as it is amenable to local gene transfection.

Topics: Arteriosclerosis; Blood Platelets; Endothelin-1; Endothelium, Vascular; Gene Expression; Genetic Therapy; Humans; Monocytes; Muscle, Smooth, Vascular; Nitric Oxide; Recurrence; Transfection

Myocardial infarction is the major cause of death in the Western world. Men are more prone to develop coronary artery disease than women, who rarely develop coronary disease before menopause. Although epidemiological data has long been available showing a protective effect of estrogen on the vascular system, the underlying mechanisms have been investigated more thoroughly only in recent years. Meta-analysis studies have revealed that only half of the protective effect on estrogen replacement therapy is due to its positive effects on the lipid profile and that a large part of this protection is caused by mechanisms distinct from lipid metabolism. It is now known that estrogens also exert effects on vascular function and structure of the vessel wall involving numerous cellular and molecular mechanisms. Here we review actions of natural estrogens on human vascular cells and arteries. Estrogens can modulate vascular function by increasing nitric oxide production via stimulation of endothelial nitric oxide synthase (eNOS) and decreasing endothelin-1 levels in vivo. Furthermore, 17 beta-estradiol is an inhibitor of vascular smooth muscle cell proliferation and migration, phenomena that play a major role in atherosclerotic vascular disease and in the remodelling process. 17 beta-estradiol can also acutely affect vascular tone in human arteries and attenuates constriction induced by contractile agonists. Finally, clinical studies have shown that 17 beta-estradiol can acutely and chronically ameliorate vascular function in women with and without vascular disease. In conclusion, results from clinical and in vitro studies confirm the positive effects of natural estrogens on vascular function and protection from coronary heart disease. Thus, primary prevention of coronary heart disease by estrogen replacement therapy after the menopause appears to be a new and straightforward approach by which cardiovascular mortality in women can be reduced.

Topics: Adult; Aged; Arteriosclerosis; Coronary Disease; Endothelin-1; Endothelium; Estradiol; Estrogen Replacement Therapy; Estrogens; Female; Humans; Male; Middle Aged; Muscle, Smooth, Vascular; Nitric Oxide Synthase

Several cardiovascular disorders, including atherosclerosis, are associated with endothelial dysfunction and enhanced expression of endothelin-1 (ET-1). The role of ET-1 in the development of endothelial dysfunction in vivo remains unclear. The objective of the present study was to investigate the effect of elevated circulating levels of ET-1 on endothelium-dependent vasodilatation (EDV), and to test the hypothesis that ET(A) receptor antagonism improves EDV in patients with atherosclerosis. EDV and endothelium-independent vasodilatation were determined by brachial artery infusion of acetylcholine and sodium nitroprusside respectively during measurement of forearm blood flow (FBF) with venous occlusion plethysmography. A 60 min intra-arterial infusion of ET-1 (n=10) significantly blunted EDV in young healthy males (33 +/- 13% compared with 271 +/- 74% increase in FBF induced by 10 mug/min acetylcholine; P<0.01). Noradrenaline, which evoked a similar degree of vasoconstriction, did not attenuate EDV. In a separate set of experiments, a 60 min intra-arterial infusion of the selective ET(A) receptor antagonist BQ123 evoked a significant increase in EDV in patients with atherosclerosis (n=10; 109 +/- 45% compared with 255 +/- 101% increase in FBF induced by 10 microg/min acetylcholine; P<0.01), whereas no significant change was observed in healthy age-matched controls (n=9). Endothelium-independent vasodilatation was not affected by ET-1 or BQ123. These observations demonstrate that elevated levels of ET-1 impair EDV in healthy control subjects. Furthermore, ET(A) receptor blockade improves EDV in patients with atherosclerosis, indicating that ET-1 attenuates EDV via an ET(A)-receptor-mediated mechanism.

Topics: Acetylcholine; Adult; Aged; Arteriosclerosis; Brachial Artery; Case-Control Studies; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Enzyme Inhibitors; Humans; Male; Middle Aged; Nitric Oxide Synthase; Nitroprusside; Norepinephrine; Peptides, Cyclic; Regional Blood Flow; Vasodilator Agents

Emerging evidence suggests that dipeptidyl peptidase-4 (DPP-4) inhibitors, including sitagliptin, exert favourable effects on the vascular endothelium. DPP-4 inhibitors suppress the degradation of glucagon-like peptide-1 (GLP‑1), which has been reported to enhance nitric oxide (NO) production. However, the effects of DPP-4 inhibitors on endothelin-1 (ET-1) expression in the aorta, as well as the underlying mechanisms responsible for these effects, have yet to be investigated in animal models of diabetes mellitus (DM). In the present study, the rats were randomly divided into the following four groups: i) control; ii) DM; iii) DM + low‑dose sitagliptin (10 mg/kg); and iv) DM + high‑dose sitagliptin (30 mg/kg). Apart from the control group, all the rats received a high-fat diet for 8 weeks prior to the induction of diabetes with an intraperitoneal injection of streptozotocin. The treatments were then administered for 12 weeks. The serum levels of ET-1, NO, GLP-1 and insulin were measured as well as endothelial function. The expression of ET-1, AMP-activated protein kinase (AMPK) and nuclear factor (NF)-κB/IκBα were determined. After 12 weeks of treatment, the diabetic rats receiving sitagliptin showed significantly elevated serum levels of GLP-1 and NO, and reduced levels of ET-1. Moreover, sitagliptin significantly attenuated endothelial dysfunction as well as the remodeling of the aortic wall. Notably, sitagliptin inhibited ET-1 expression at the transcriptional and translational level in the aorta, which may have been mediated by the suppression of the NF-κB/IκBα system induced by AMPK activation. The majority of the above-mentioned effects were dose dependent. Taken together, the findings of the present study indicate that sitagliptin inhibits ET-1 expression in the aortic endothelium by suppressing the NF-κB/IκBα system through the activation of the AMPK pathway in diabetic rats. These findings further demonstrate some of the vasoprotective properties of DPP-4 inhibitors in vivo.

Topics: AMP-Activated Protein Kinases; Animals; Aorta; Arteriosclerosis; Diabetes Mellitus, Experimental; Diet, High-Fat; Dipeptidyl-Peptidase IV Inhibitors; Dose-Response Relationship, Drug; Endothelin-1; Endothelium, Vascular; Gene Expression Regulation; Glucagon-Like Peptide 1; Hypoglycemic Agents; I-kappa B Kinase; Male; NF-kappa B; Nitric Oxide; Rats; Rats, Sprague-Dawley; Signal Transduction; Sitagliptin Phosphate; Streptozocin

Familial hypercholesterolemia (FH) is characterized by a high incidence of coronary heart disease. Evidence suggests an important role for angiotensin II (AngII) in the fibrotic response to tissue injury, and in promoting myocardial hypertrophy via paracrine mechanisms mediated by fibroblasts. We sought to determine whether AngII promotes proliferative and pro-atherogenic responses in FH patients.. We used primary fibroblasts -- from five patients with heterozygous FH and five control subjects (C) -- to study AngII-induced cell growth, intracellular calcium fluxes, and expression/release of matrix components and pro-inflammatory peptides [transforming growth factor-beta1 (TGFbeta1) and endothelin-1 (ET-1)] and metalloproteinases involved in plaque remodeling and vulnerability.. AngII stimulated cell replication (5.1 +/- 0.03 versus 3.2 +/- 0.04 cells/50 cells per well, P < 0.001), and induced a larger increase in intracellular calcium content in FH cells than in C cells, in a dose-dependent fashion (mean difference = 76 nmol/l, P < 0.001). Similarly, TGFbeta1 and ET-1 expression and release were potentiated (after 24-h incubation with 1 micromol/l AngII: TGFbeta1 was 190 +/- 12 in C and 376 +/- 9 pg/ml per 10(6) cells in FH, and ET-1 was 93 +/- 5 in C and 192 +/- 7 pmol/ml per 10(6) cells in FH; P < 0.001 for both). AngII-induced release of the metalloproteinases MMP-1 and MMP-2 was also increased in FH versus C cells (0.52 +/- 0.04 versus 0.36 +/- 0.05 and 24 +/- 4 versus 13 +/- 3 ng/mg protein with 1 micromol/l AngII). These enhanced responses were likely due to an increased angiotensin receptor 1 (AT1) expression in cells from FH patients induced by AngII, and were prevented by pretreating cells with the selective AT1 antagonist irbesartan.. These findings show that some AngII-mediated pathways are enhanced in FH subjects irrespective of the presence of low-density lipoprotein (LDL), thus contributing to the development and progression of atherosclerosis in these patients.

Topics: Adult; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Arteriosclerosis; Biphenyl Compounds; Calcium; Case-Control Studies; Cell Proliferation; Cells, Cultured; Cholesterol, LDL; Dose-Response Relationship, Drug; Endothelin-1; Female; Fibroblasts; Heterozygote; Humans; Hyperlipoproteinemia Type II; Irbesartan; Male; Matrix Metalloproteinase 1; Matrix Metalloproteinase 2; Middle Aged; Receptor, Angiotensin, Type 1; Tetrazoles; Transforming Growth Factor beta

Low adipocyte IRS-1 protein expression is a biomarker for insulin resistance and early atherosclerosis. However, whether IRS-1 protein expression is related to systemic arterial stiffness, is unknown.. Ten non-diabetic male subjects with low adipocyte IRS-1 protein expression (LIRS) were matched with 10 non-diabetic males with normal IRS-1 protein expression (NIRS). Augmentation index (AIx) and time for reflection of pulse wave (Tr) were studied with pulse wave analysis, both in the fasting state and during a euglycemic hyperinsulinemic clamp. The LIRS-group showed an increased fasting insulin concentration (fP-insulin 71+/-4 pmol/L versus 58+/-5 pmol/L; p=0.02 (mean+/-S.E.)), whereas glucose disposal rate during the clamp (8.7+/-0.8 mg/kg LBM/min versus 10.3+/-1.3 mg/kg LBM/min; n.s.) did not differ significantly. Blood pressure, lipid parameters, adiponectin, endothelin-1 and CRP concentrations were similar. However, in the basal state, AIx was increased (129+/-4% versus 116+/-2%; p<0.02) and Tr was decreased (150+/-3 ms versus 171+/-5 ms; p<0.01), suggesting stiffer vessels in the LIRS-group. The LIRS-group exhibited an attenuated AIx response to hyperinsulinemia compared to the NIRS-group.. The data suggest that non-obese non-diabetic men with a low adipocyte IRS-1 protein expression have an increased systemic arterial stiffness.

Topics: Adipocytes; Adiponectin; Adult; Arteriosclerosis; Biomarkers; Blood Glucose; C-Reactive Protein; Diabetes Mellitus; Endothelin-1; Fasting; Female; Glucose Clamp Technique; Humans; Hyperinsulinism; Insulin Receptor Substrate Proteins; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Male; Middle Aged; Phosphoproteins

Increased oxidative stress in vascular cells plays a key role in the development of endothelial dysfunction and atherosclerosis. Uncoupling protein 2 (UCP2) is an important regulator of intracellular reactive oxygen species (ROS) production. This study was undertaken to test the hypothesis that, UCP2 functions as an inhibitor of the atherosclerotic process in endothelial cells. Adenovirus-mediated UCP2 (Ad-UCP2) overexpression led to a significant increase in endothelial nitric oxide synthase (eNOS) and decrease in endothelin-1 mRNA expression in human aortic endothelial cells (HAECs). Moreover, UCP2 inhibited the increase in ROS production and NF-kappaB activation, and apoptosis of HAECs induced by lysophophatidylcholine (LPC) and linoleic acid. LPC and linoleic acid caused mitochondrial calcium accumulation and transient mitochondrial membrane hyperpolarization, which was followed by depolarization. UCP2 overexpression prevented these processes. In isolated rat aorta, Ad-UCP2 infection markedly improved impaired vascular relaxation induced by LPC. The data collectively suggest that UCP2, functions as a physiologic regulator of ROS generation in endothelial cells. Thus, measures to increase UCP2 expression in vascular endothelial cells may aid in preventing the development and progression of atherosclerosis in patients with metabolic syndrome.

Topics: Adenoviridae; Apoptosis; Arteriosclerosis; Calcium; Caspases; Cells, Cultured; Electron Transport; Endothelial Cells; Endothelin-1; Gene Transfer, Horizontal; Humans; Ion Channels; Linoleic Acid; Lysophosphatidylcholines; Membrane Transport Proteins; Mitochondrial Proteins; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Reactive Oxygen Species; RNA, Messenger; Uncoupling Protein 2

Chronic inhibition of nitric oxide (NO) synthesis by administration of high dose of N(G)-nitro-L-arginine methylester (L-NAME) induces vascular inflammation and subsequent atherosclerosis. We aimed to investigate whether the methanol extract of Sorbus commixta cortex (MSC) is able to prevent inflammatory process in a rat model of L-NAME-induced atherosclerosis. Chronic treatment with low or high doses of MSC prevented the L-NAME-induced increase in monocyte chemoattractant protein-1 (MCP-1) and nuclear factor-kappaB (NF-kappaB) p65 expressions as well as adhesion molecules including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in aorta. In addition, increased endothelin-1 (ET-1) and angiotensin converting enzyme (ACE) expressions and decreased endothelial cell NO synthase (ecNOS) expression in aorta from L-NAME treated group was reversed by treatment with MSC. From the histological examination, aortic segment from the L-NAME-treated rats revealed a thickening of intima and media, which was ameliorated by treatment with MSC. In conclusion, our results indicate that MSC can prevent atherosclerosis by inhibiting vascular over-expressions of vasoactive materials, pro-inflammatory transcription factor, and adhesion molecules and by augmenting ecNOS in chronic L-NAME-treated rat model.

Topics: Animals; Arteriosclerosis; Base Sequence; Cell Adhesion Molecules; Chemokine CCL2; DNA Primers; Endothelin-1; Methanol; NF-kappa B; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Plant Extracts; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sorbus; Transcription Factor RelA

BACKGROUND.: Transplant arteriosclerosis is one of the main features of chronic graft failure in organ transplantation. In this article, the authors investigate mechanisms of mycophenolate mofetil (MMF) on prevention of transplant arteriosclerosis in a rat aortic allograft model.. Orthotopic rat abdominal aortic transplantation was performed from Brown Norway (RT1) to Lewis (RT1) rats. The recipients were divided into three oral treatment groups: (1). vehicle; (2). MMF40 (40 mg/kg); and (3). MMF20 (20 mg/kg). The authors histologically and immunohistochemically evaluated neointima formation; infiltration of macrophages and T cells; and expression of endothelin (ET)-1, platelet-derived growth factor (PDGF)-B, PDGF receptor-beta (Rbeta), transforming growth factor (TGF) beta 1, and osteopontin (OPN). Using cultured rat vascular smooth muscle cells (VSMC), effects of mycophenolic acid (MPA) on ET-1-induced proliferation and ERK1/2 activation were also examined in vitro.. In the vehicle group, marked neointima formation was observed, with massive macrophages and T-cell infiltration in neointima, media, and adventitia. Marked expression of ET-1, PDGF-B, PDGFR-beta, TGFbeta1, and OPN were also observed in neointima. In the MMF40 and MMF20 groups, neointima formation was halted, but macrophages and T cells were infiltrated in the adventitia and adhered to the endothelium. In the MMF40 group, medial infiltration by macrophages and T cells and intimal expression of ET-1, PDGF-B, PDGFR-beta, TGFbeta1, and OPN was inhibited compared with the vehicle and MMF20 groups. Furthermore, MPA inhibited ET-1-induced VSMC proliferation but failed to inhibit its ERK1/2 activation.. MMF treatment might have preventive potential in transplant patients with chronic vasculopathy through inhibition of VSMC proliferation.

Topics: Animals; Aorta, Abdominal; Aortic Diseases; Arteriosclerosis; Body Weight; Cell Division; Cells, Cultured; Endothelin-1; Growth Substances; Immunosuppressive Agents; Macrophages; Male; Muscle, Smooth, Vascular; Mycophenolic Acid; Myocytes, Smooth Muscle; Rats; Rats, Inbred BN; Rats, Inbred Lew; Rats, Sprague-Dawley; T-Lymphocytes; Tunica Intima

The novel vaso-constricting 31-amino acid-length endothelin-1 [ET-1(1-31)] is selectively produced by human mast cell chymase via its action on big ET-1. However, the pathological role of ET-1(1-31) in atherosclerosis remains unclear. The aim of this study was to clarify vasoconstrictive response and expression of ET-1(1-31) in atherosclerotic aorta.. Syrian golden hamster, was used for preparing the atherosclerotic models by the administration of a high cholesterol diet (HC), treatment with the nitric oxide synthase inhibitor (Nomega-nitro-L-arginine methylester, L-NAME) alone, or both (HC and L-NAME) for 40 weeks. Early atherosclerosis was observed in the case of HC or L-NAME alone treatments respectively and severe atherosclerosis was observed in the case of combined HC and L-NAME treatment. Vasoconstriction induced by ET-1(1-31) was not altered by the atherosclerotic changes, but the expression pattern of ET-1(1-31) was different at each stage of the atherosclerotic aorta. ET-1(1-31) was observed rarely in normal aortas or in early atherosclerotic lesions, but ET-1(1-31) expression was dramatically increased in aortic neointima and adventitia in a state of atherosclerosis with severe inflammation.. ET-1(1-31) might play in a role of promoting atherosclerosis, and especially be involved in inflammatory mediation during the progression of atherosclerosis.

Topics: Animals; Aorta, Thoracic; Arteriosclerosis; Blood Pressure; Cholesterol; Cricetinae; Disease Models, Animal; Endothelin-1; Heart Rate; Hypercholesterolemia; Male; Peptide Fragments; Triglycerides; Vasoconstriction

Both plaque-free and plaque-prone hemodynamic environments induce an increase in the oxidative state of endothelial cells (ECs), whereas differential gene expression regulation was described in cells exposed to these conditions. In order to investigate the role of the increased oxidative state in flow-regulation of gene expression, we first exposed EC to non-pulsed unidirectional shear stress. These conditions only slightly increases ECs oxidative state and endothelin-1 (ET-1) mRNA expression, whereas endothelial nitric oxide synthase (NOS III) mRNA level were significantly up-regulated. On the contrary, both ET-1 and NOS III gene expression were significantly induced in EC exposed to pulsed-unidirectional flow (plaque-free). Only ET-1 gene expression was up-regulated by oscillatory flow (plaque-prone). Moreover, use of an antioxidant only partially inhibited NOS III gene up-regulation by unidirectional flow, whereas it completely abrogated ET-1 gene up-regulation by unidirectional and oscillatory flows. Thus suggesting that mechanical forces regulate gene expression in ECs both via oxidative stress-dependent and -independent mechanisms.

Topics: Animals; Antioxidants; Arteriosclerosis; Cattle; Cell Culture Techniques; Endothelin-1; Endothelium, Vascular; Gene Expression Regulation; Hemodynamics; Hemorheology; Mechanotransduction, Cellular; Nitric Oxide Synthase; Oxidation-Reduction; Pulsatile Flow; RNA, Messenger; Stress, Mechanical

We previously found that human chymase cleaves big endothelins at the Tyr31-Gly32 bond and produces 31-amino-acid endothelins, endothelins(1-31). Endothelin-1(1-31) has been isolated from a number of human organs, including the heart and lungs. As endothelin-1 has been shown to play a significant role in the paracrine regulation of cardiovascular functions in humans, it is possible that endothelin-1(1-31) may also exhibit biological activity on human tissues. We previously reported that synthetic endothelin-1(1-31) exhibits a number of physiological actions on cultured cells in vitro. In the present study, we investigated the plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and compared them with those in patients with cardiovascular diseases. Endothelin-1(1-31) and endothelin-1 in human plasma was measured using a sandwich-enzyme-immunoassay system, which was recently described for measurement of endothelin-1(1-31). The plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy volunteers were 19.24 +/- 5.70 and 15.54 +/- 4.45 pg/ml (n = 5), respectively. We also measured plasma concentrations of endothelin-1(1-31) and endothelin-1 before and after surgery in patients with abdominal aortic aneurysms. Before surgery, plasma concentrations of endothelin-1(1-31) and endothelin-1 in these patients were higher than those in healthy individuals. After surgery, both endothelin-1(1-31) and endothelin-1 in plasma decreased to levels similar to those of healthy subjects. This suggests that endothelin-1(1-31) may have similar physiological significance to endothelin-1 in patients with atherosclerosis.

Topics: Adult; Aged; Aortic Aneurysm, Abdominal; Arteriosclerosis; Endothelin-1; Humans; Male; Middle Aged; Peptide Fragments

Endothelin-1 (ET-1) is a potent vasoconstrictor that increases vascular tone in the resistance vessels of subjects with hypertension. It is unclear whether endogenous ET-1 affects resistance-vessel function equally in patients with other cardiovascular risk factors. Vasoconstriction to ET-1 is mediated principally via the endothelin-A (ETA) receptor on vascular smooth muscle cells. Accordingly, we used an ETA-specific antagonist, BQ-123, to test the hypothesis that endogenous ET-1 increases vascular resistance selectively in subjects with hypertension compared with other risk factors. BQ-123 was infused at 100 nmol/min for 80 minutes into the brachial artery of 10 subjects with hypertension (mean+/-SEM arterial pressure, 106+/-5 mm Hg), 12 subjects with hypercholesterolemia (mean+/-SEM total cholesterol, 7.1+/-0.2 mmol/L), 10 active smokers (mean+/-SEM, 42+/-11 pack-years), and 11 healthy, age-matched individuals. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. BQ-123 dilated resistance arterioles in hypertensive subjects, with FBF's increasing by 46+/-7% from baseline (P<0.001). BQ-123 increased FBF to a lesser extent in hypercholesterolemic (24+/-5%, P<0.001) and healthy (20+/-8%, P=0.007) individuals but did not affect FBF significantly in smokers (10+/-8%, P=0.185). The vasodilator response in hypertensive subjects, but not in hypercholesterolemic patients or smokers, was significantly greater than that in healthy individuals (P=0.012). Endogenous ET-1, acting via the ETA receptor, increases resistance-vessel tone in subjects with hypertension more than in subjects with hypercholesterolemia or in smokers. These results indicate that ET-1 contributes more to the pathophysiology of hypertension than of other risk factors in subjects without overt atherosclerosis.

Topics: Arteriosclerosis; Endothelin Receptor Antagonists; Endothelin-1; Female; Forearm; Humans; Hypercholesterolemia; Hypertension; Male; Middle Aged; Peptides, Cyclic; Receptor, Endothelin A; Regional Blood Flow; Risk Factors; Smoking; Vascular Resistance; Vasodilation

Inflammatory mediators secreted by leukocytes are implicated in atherogenesis. Chlamydia (C.) pneumoniae infection has been suggested as a trigger of this process. We investigated relationships between C. Pneumoniae serology, inflammatory mediators and symptomatic cardiovascular disease in old age.. In a cross-sectional study at baseline with a prospective 4 year follow-up, intraplatelet cyclic 3'-5'adenosine monophosphate (cAMP) and cyclic 3'-5'guanosine monophosphate (cGMP), plasma neutrophil gelatinase associated lipocalin (NGAL), plasma soluble tumor necrosis factor receptor-1 (TNFR-1) plasma neopterin and plasma endothelin-1 (ET-1) were analysed together with IgG and IgA antibodies for C. Pneumoniae in an elderly reference population (n=140, median age 71 years, 71 females). Twenty-one subjects had clinical manifestations of cardiovascular disease at baseline and another 21 were diagnosed with cardiovascular disease during follow-up.. In age adjusted logistic regression, subjects with cardiovascular disease showed higher plasma levels of neopterin (p=0.02), NGAL (p=0.04), and ET-1 (p<0.01). If subjects with cardiovascular disease at baseline were excluded from the analysis, higher plasma neopterin (p=0.01) and lower serum HDL cholesterol (p=0.03) predicted cardiovascular disease during follow-up. The presence of IgG or IgA against C. pneumoniae was not associated with cardiovascular disease. Neither were there any associations between inflammatory or endothelial parameters and C. pneumoniae serology.. The inflammatory mediators neopterin and NGAL and endothelial derived vasoconstrictive ET-1 were increased in elderly subjects with symptomatic cardiovascular disease. Increased plasma neopterin predicted cardiovascular disease during follow-up. No relationships were found between C. Pneumoniae serology and cardiovascular disease.

Topics: Acute-Phase Proteins; Aged; Arteriosclerosis; Carrier Proteins; Chlamydophila Infections; Chlamydophila pneumoniae; Cross-Sectional Studies; Cyclic AMP; Cyclic GMP; Endothelin-1; Female; Humans; Lipocalin-2; Lipocalins; Logistic Models; Male; Neopterin; Oncogene Proteins; Proto-Oncogene Proteins

Endothelin-1 (ET-1) may be involved in the development and progression of atherosclerosis. Furthermore, endothelin receptor blockade was shown to reduce the formation of atherosclerotic lesions in experimental studies. Another potent pro-atherosclerotic risk factor is oxidized low-density lipoprotein (oxLDL). Endothelial cells mediate the uptake of oxLDL by the recently identified lectin-like oxLDL receptor-1 (LOX-1), which accumulates in atherosclerotic lesions. In the present study, we analysed the effects of ET-1 on oxLDL uptake and LOX-1 expression in primary cultures of human umbilical vein endothelial cells (HUVEC). ET-1 stimulated uptake of oxLDL in HUVEC, which reached a maximum after 1 h. In further studies, we found a similar induction of LOX-1 mRNA and protein expression in response to ET-1. The augmented oxLDL uptake and the increased LOX-1 expression in response to ET-1 are mediated by the endothelin receptor B. Our data support a new pathophysiological mechanism by which locally and systemically increased ET-1 levels, e.g. in hypertensive patients, could promote LOX-1-mediated oxLDL uptake in human endothelial cells. This mechanism could promote the development and progression of endothelial dysfunction and atherosclerosis. In addition, endothelin receptor blockade could be considered as a new anti-atherosclerotic therapeutic principle.

Topics: Arteriosclerosis; Cells, Cultured; Endothelin-1; Endothelium, Vascular; Humans; Lipoproteins, LDL; Receptors, LDL; Receptors, Oxidized LDL; RNA, Messenger; Scavenger Receptors, Class E; Stimulation, Chemical; Umbilical Veins

The effect of previous nitrate therapy on vascular responses to endothelin-1 (ET-1) and NO was investigated in human internal mammary artery (IMA) in vitro. Cumulative concentration-response curves to ET-1 were constructed in rings of IMA and the data grouped into IMA from patients given nitrates prior to the bypass graft operation (nitrate group) and IMA from patients who were not prescribed nitrates (control group). No significant differences were observed between the two groups, either in EC(50) value [P>0.05; 3.5 nM (2.4-5.3 nM; 95% confidence interval) and 4.8 (2.2-10 nM), nitrate and control groups respectively] or E(max) (P>0.05; 78+/-7.5% and 85+/-9.5%, nitrate and control group respectively). No significant differences in concentration-response curves to the NO-donor diethylamine NONOate (DEA/NO) in rings of IMA pre-constricted with 10 nM ET-1 were observed between control and nitrate groups [P>0.05; EC(50) values 0.59 (0.21-1.7) microM and 0.17 (0.03-0.87) microM; E(max) 110+/-5.7% and 112+/-4.5%, nitrate and control groups respectively]. Concentration-response curves to DEA/NO constructed in normal coronary artery were not significantly different from those in coronary artery obtained from patients with ischaemic heart disease (IHD) [P>0.05; E(max) 124+/-11% and 138+/-20%; EC(50) 0.08 (0.02-0.30) microM and 0.23 (0.02-24) microM, normal and IHD respectively]. These data indicate that nitrate therapy does not induce long-term changes in the ET signalling pathway. Furthermore, the tolerance to nitrate therapy is likely to be because of impaired bio-transformation of the drug rather than reduced sensitivity of the media to NO. The similar responses to DEA/NO in normal and atherosclerotic coronary artery suggests that the reduced vasodilator responses in IHD is because of a dysfunctional endothelium and is not mediated by changes in the NO signalling pathway of the smooth muscle.

Topics: Arteriosclerosis; Coronary Vessels; Dose-Response Relationship, Drug; Endothelin-1; Humans; Hydrazines; In Vitro Techniques; Mammary Arteries; Muscle, Smooth, Vascular; Nitrates; Nitric Oxide Donors; Nitrogen Oxides; Statistics, Nonparametric; Vasoconstrictor Agents

We examined the mechanism of action of lysophosphatidylcholine (lyso-PC), which is suggested to be involved in the pathogenesis of atherosclerosis and inflamatory disorders, and its interaction with well-known vasoactive compounds such as hydrogen peroxide (H2O2), thromboxane A2 (TX-A2), serotonin (5-HT), angiotensin II (Ang-II), endothelin-1 (ET-1), or urotensin II (U-II) on VSMC proliferation. Growth-arrested rabbit VSMCs were incubated with given concentrations of lyso-PC with H202, TX-A2, 5-HT, Ang-II, ET-1, or U-II. [3H]Thymidine incorporation into DNA was measured as an index of VSMC proliferation. Lyso-PC induced a maximal effect on [3H]thymidine incorporation at a concentration of 15 microM (156%), and its effect was significantly inhibited by the phospholipase C inhibitor U73122 (10 microM), the intracellular antioxidant NAC (400 microM), and the NADPH oxidase inhibitor diphenylene iodonium (1 microM), but not by the MAPK kinase inhibitor (10 microM). H2O2, TX-A2, 5-HT, Ang-II, ET-1, or U-II also stimulated [3H]thymidine incorporation in a dose-dependent manner. A non-mitogenic concentration of lyso-PC (5 microM) significantly potentiated the effect of low concentrations of H2O2 (0.1 microM, 110 to 222%), TX-A2 (5 microM, 120 to 202%), 5-HT (5 microM, 182 to 259%), Ang-II (0.5 microM, 167 to 304%), ET-1 (0.01 microM, 139 to 297%), or U-II (0.025 microM, 120 to 332%) on [3H]thymidine incorporation. The results suggest that lyso-PC acts synergistically with the vasoactive compounds H2O2, TX-A2, 5-HT, Ang-II, ET-1, or U-II in inducing VSMC proliferation, which may play an important role in the progression of atherosclerosis.

Topics: Angiotensin II; Animals; Aorta; Arteriosclerosis; Cells, Cultured; DNA; Drug Synergism; Endothelin-1; Hydrogen Peroxide; Lysophosphatidylcholines; Mitogens; Muscle, Smooth, Vascular; Rabbits; Serotonin; Thromboxane A2; Thymidine; Type C Phospholipases; Urotensins; Vasoconstrictor Agents

Topics: Aging; Animals; Arteriosclerosis; Carrier Proteins; Endothelin-1; Endothelins; Humans; Mice; Nitric Oxide; Ubiquitin-Protein Ligases

The enhanced production of endothelin-1 (ET-1) in atherosclerotic arteries may be related to increased activity of the endothelin converting enzyme (ECE) which converts big ET-1 to ET-1. The purpose of the present study was to investigate whether the vasoconstrictor activity of big ET-1 is altered as a result of increased conversion to ET-1 in patients with atherosclerosis. Big ET-1 was infused into the brachial artery of nine patients with atherosclerosis and nine healthy controls. Forearm blood flow (FBF) was measured with venous occlusion plethysmography. Big ET-1 (15 and 50 pmol/min) evoked more pronounced reduction in FBF in the patients than in the controls (P<0.01). The low dose big ET-1 elevated local venous plasma ET-1 (from 2.8+/-0.3 to 9.0+/-1.6 pmol/l; P<0.01) and the net formation of ET-1 (from -6.6+/-8.6 to 50.5+/-16.0 fmol/min; P<0.01) in the patients but not in the controls. Furthermore, histological examination revealed ECE immunoreactivity in the fibrous cap of atherosclerotic plaques in addition to the endothelium and smooth muscle cells of radial arteries. In conclusion, administration of big ET-1 results in enhanced vasoconstriction and increased formation of ET-1 in patients with atherosclerosis as compared to healthy controls which may be due to increased activity of ECE.

Topics: Aged; Arteriosclerosis; Aspartic Acid Endopeptidases; Blood Pressure; Dose-Response Relationship, Drug; Endothelin-1; Endothelin-Converting Enzymes; Endothelins; Endothelium, Vascular; Forearm; Humans; Immunohistochemistry; Male; Metalloendopeptidases; Middle Aged; Muscle, Smooth, Vascular; Protein Precursors; Regional Blood Flow; Vascular Resistance; Vasoconstriction

We wanted to determine whether a previously described in vivo accumulation of a (99m)Tc-labeled endothelin derivative in atherosclerotic lesions is mediated by binding to endothelin receptors. Furthermore, the expression of endothelin receptors in atherosclerotic lesions of 2 different rabbit animal models for atherosclerosis was to be evaluated to determine whether endothelin receptors generally are a suitable target for atherosclerosis imaging.. Normal vessels from untreated New Zealand White rabbits (NZW), balloon-denuded aortas from cholesterol-fed NZW, and atherosclerotic aortas from Watanabe Heritable Hyperlipidemic rabbits (WHHL) were used either as cross sections (cryosections) for receptor binding studies or for superfusion with a medium containing (125)I-labeled endothelin-1 or the (99m)Tc-labeled endothelin derivative.. Cross sections of aortas from untreated NZW contained 45 +/- 11.10(6) endothelin A receptors per square millimeter and 55 +/-11.10(6).endothelin B receptors per square millimeter, cross sections of balloon-denuded aortas from cholesterol-fed NZW contained 106 +/- 16.10(6) endothelin A receptors per square millimeter and 27 +/- 16.10(6) endothelin B receptors per square millimeter, and cross sections of atherosclerotic aortas from WHHL contained 40 +/- 13.10(6) endothelin A receptors per square millimeter and 5 +/- 13.10(6) endothelin B receptors per square millimeter. Balloon-denuded aortas from cholesterol-fed NZW (366 +/- 132 amol.mm(-2), P < 0.001) and atherosclerotic aortas from WHHL (338 +/- 175 amol.mm(-2), P < 0.002) accumulated significantly more of the (99m)Tc-labeled endothelin derivative than did vessels from control animals (137 +/- 26 amol.mm(-2)). On the contrary, (125)I-labeled endothelin-1--bound receptor mediated to superfused aortas from untreated NZW (12 +/- 9 amol.mm(-2)) and to balloon-denuded aortas from cholesterol-fed NZW (19 +/- 5 amol.mm(-2)) but not to aortas from WHHL. This lack of receptor-specific accumulation of (125)I-endothelin-1 in atherosclerotic areas of WHHL aortas, and this receptor-specific accumulation in atherosclerotic balloon-denuded NZW aortas that does not significantly increase in comparison with normal aortas of untreated NZW, cause failure of endothelins to detect atherosclerotic lesions.. Although the density and the ratio of endothelin receptor subtypes change because of the development of atherosclerotic lesions in rabbit aortas, endothelin receptor targeting for imaging of atherosclerosis is not suitable.

Topics: Animals; Aorta; Arteriosclerosis; Endothelin-1; Endothelin-2; Female; In Vitro Techniques; Iodine Radioisotopes; Rabbits; Radionuclide Imaging; Receptors, Endothelin; Technetium

Endothelin (ET)-1 causes vasoconstriction via ET(A) and ET(B) receptors located on vascular smooth muscle cells and vasodilatation via ET(B) receptors on endothelial cells. Studies in vitro indicate an upregulation of ET(B) receptors in atherosclerosis. The present study investigated the vascular effects evoked by endogenous ET-1 in atherosclerotic patients. Forearm blood flow (FBF) was measured with venous occlusion plethysmography in 10 patients with atherosclerosis and in 10 healthy control subjects during intra-arterial infusion of selective ET receptor antagonists. The ET(B) receptor antagonist BQ788 evoked a significant increase in FBF (31+/-13%) in the patients, whereas a 20+/-9% reduction was observed in the control subjects. The ET(A) receptor antagonist BQ123 combined with BQ788 evoked a marked increase in FBF (102+/-25%) in the patients compared with no effect in the control subjects (-3+/-9%, P<0.001 versus patients). The ET(A) receptor antagonist BQ123 increased FBF to a similar degree in patients (39+/-11%) as in control subjects (41+/-11%). The increase in FBF evoked by selective ET(A) receptor blockade was significantly (P<0.05) less than that evoked by combined ET(A)/ET(B) receptor blockade in the atherosclerotic patients. These observations suggest an enhanced ET-1-mediated vascular tone in atherosclerotic patients, which is at least partly due to increased ET(B)-mediated vasoconstriction.

Topics: Antihypertensive Agents; Arteriosclerosis; Case-Control Studies; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Forearm; Humans; Male; Middle Aged; Oligopeptides; Peptides, Cyclic; Piperidines; Receptor, Endothelin A; Receptor, Endothelin B; Regional Blood Flow; Up-Regulation; Vasodilation

C-reactive protein (CRP) has been suggested to actively participate in the development of atherosclerosis. In the present study, we examined the role of the potent endothelium-derived vasoactive factor endothelin-1 (ET-1) and the inflammatory cytokine interleukin-6 (IL-6) as mediators of CRP-induced proatherogenic processes.. Saphenous vein endothelial cells (HSVECs) were incubated with human recombinant CRP (25 microg/mL, 24 hours) and the expression of vascular cell adhesion molecule (VCAM-1), intracellular adhesion molecule (ICAM-1), and monocyte chemoattractant chemokine-1 was determined. The effects of CRP on LDL uptake were assessed in macrophages using immunofluorescent labeling of CD32 and CD14. In each study, the effect of endothelin antagonism (bosentan) and IL-6 inhibition (monoclonal anti-IL-6 antibodies) was examined. The effects of CRP on the secretion of ET-1 and IL-6 from HSVECs were also evaluated. Incubation of HSVECs with recombinant human CRP resulted in a marked increase in ICAM-1 and VCAM-1 expression (P<0.001). Likewise, CRP caused a significant increase in monocyte chemoattractant chemokine-1 production, a key mediator of leukocyte transmigration (P<0.001). CRP caused a marked and sustained increase in native LDL uptake by macrophages (P<0.05). These proatherosclerotic effects of CRP were mediated, in part, via increased secretion of ET-1 and IL-6 (P<0.01) and were attenuated by both bosentan and IL-6 antagonism (P<0.01).. CRP actively promotes a proatherosclerotic and proinflammatory phenotype. These effects are mediated, in part, via the production of ET-1 and IL-6 and are attenuated by mixed ET(A/B) receptor antagonism and IL-6 inhibition. Bosentan may be useful in decreasing CRP-mediated vascular disease.

Topics: Antibodies; Arteriosclerosis; Biomarkers; Bosentan; C-Reactive Protein; Cell Adhesion Molecules; Cells, Cultured; Chemokine CCL2; Endothelin-1; Endothelium, Vascular; Humans; Inflammation; Interleukin-6; Lipoproteins, LDL; Macrophages; Models, Cardiovascular; Sulfonamides

Many cytokine genes, including those encoding acute-phase proteins and immunoglobulins, share binding sites for the CCAAT/enhancer-binding protein (C/EBP) in their 5'-flanking regions, and C/EBP-related transcription factors regulate cell proliferation during terminal differentiation. Therefore, C/EBP represents an attractive target for inhibiting restenosis after balloon angioplasty. In a rabbit model of restenosis that combines balloon injury of the carotid artery with cholesterol-mediated chronic inflammation, a decoy oligodeoxynucleotide (ODN) capable of neutralizing C/EBP was administered to the site of injury for 30 minutes. Electrophoretic mobility shift analysis confirmed that C/EBP activity in decoy ODN-treated segments was virtually absent after 2 days. Morphometric analysis after 28 days revealed significant reduction (up to 50%) of neointimal formation and intravascular inflammation in decoy ODN-treated segments compared with mutant control ODN or vehicle-treated segments. In addition, de novo synthesis of endothelin-1 and the number of proliferating cell nuclear antigen-positive smooth muscle cells in the vessel wall were markedly attenuated at day 3. These findings suggest that decoy ODN-based neutralization of C/EBP may be a feasible and effective method to limit restenosis after angioplasty brought about, at least in part, by inhibiting the de novo synthesis of endothelin-1.

Topics: Animals; Arteriosclerosis; Catheterization; CCAAT-Enhancer-Binding Proteins; Disease Models, Animal; Endothelin-1; Hypercholesterolemia; Immunohistochemistry; Macrophages; Male; Oligodeoxyribonucleotides; Rabbits; Recurrence; Treatment Outcome; Tunica Intima

To investigate the mechanism of xiaoyu tablet on reduction of smooth muscle cells (SMC) in atherosclerotic vessel wall.. The atherosclerotic model was performed in male New Zealand rabbits that were given high fat diet and abrasion of the abdominal aorta endothelial cells. The rabbits were then administered with xiaoyu tablet 0.16-0.32 g x kg(-1) x d(-1) for 16 weeks. Changes in morphology, endothelin (ET)-1, nitric oxide (NO), and apoptotic cells of atherosclerotic vessel wall were determined by the microscopy, radioimmunoassay, colorimetric method, the techniques of DNA in situ end labeling, and image pattern analysis, respectively.. After 16 weeks of xiaoyu tablet treatment, intimal thickness and SMC in atherosclerotic vessel wall were diminished, ET-1 was decreased by 8.2 %-42.6 %, NO was increased by 7.5 %-54.2 %, and labeled apoptotic nuclei were markedly decreased, the area and integral optical density of positive granule were (846+/-308) microm2 and 3425+/-1374 in atherosclerotic group and (225+/-60) microm2 and 1445+/-606 in xiaoyu tablet 0.32 g/kg group, respectively.. Xiaoyu tablet not only inhibited proliferation of SMC through reducing ET-1 in atherosclerotic vessel wall, but also induced apoptosis of SMC by increasing NO in vessel wall.

Topics: Animals; Aorta, Abdominal; Apoptosis; Arteriosclerosis; Crataegus; Drug Combinations; Drugs, Chinese Herbal; Endothelin-1; Male; Muscle, Smooth, Vascular; Nitric Oxide; Plants, Medicinal; Rabbits; Salvia miltiorrhiza; Tablets

Elevated plasma levels of endothelin-1 (ET-1) have been reported in advanced atherosclerosis. Further in vivo demonstration of cause-effect relationship between atherosclerotic lesion and high levels of ET-1 needs to be carried out. The aim of this study was to determine whether circulating levels of ET-1 are influenced by removing haemodynamically significant atherosclerotic stenosis in selected patients with mono or bilateral carotid atherosclerotic stenosis.. Cubital venous ET-1-immunoreactive (IR) levels were measured in 20 patients: 11 (mean age+/-S.D. 63.1+/-5.36 years; range 53-70 years) were affected by monolateral, and nine patients (mean age+/-S.D. 64.7+/-9.8 years; range 52-78 years) by bilateral extracranial carotid artery atherosclerotic stenosis. ET-1-IR levels were evaluated before and 7 days after monolateral surgical endoarterectomy. Pre-surgery levels of ET-1-IR were compared with those obtained from 18 healthy younger volunteers (mean age+/-S.D. 27.8+/-2.7 years; range 20-50 years).. The mean cubital venous levels of ET-1-IR in the atherosclerotic patients before endoarterectomy (mean+/-S.D. 4.50+/-3.35 pg/ml; range 1.28-10.66 pg/ml) were significantly higher than those observed in healthy subjects (mean+/-S.D. 0.641+/-0.137 pg/ml; range 0.36-1.02 pg/ml) (P=0.000). The mean ET-1-IR level decreased significantly after endoarterectomy in the group of patients with monolateral stenosis (pre-surgery: mean+/-S.D. 4.35+/-3.11 pg/ml; range 1.28-10.66 pg/ml; post-surgery: mean+/-S.D. 3.05+/-2.94 pg/ml, range 0.28-8.86 pg/ml) (P=0.005), but not in patients with bilateral extracranial carotid stenosis submitted to monolateral endoarterectomy (pre-surgery: mean+/-S.D. 4.77+/-3.79 pg/ml; range 2.18-10.3 pg/ml; post-surgery: mean+/-S.D. 4.60+/-3.70 pg/ml; range 2.20-11.10 pg/ml).. The removal of a haemodynamically significant atherosclerotic vascular stenosis is associated with a decrease in the circulating ET-1-IR levels 7 days after surgery when haemodynamically significant atherosclerotic lesions are absent.

Topics: Aged; Arteriosclerosis; Carotid Stenosis; Endarterectomy, Carotid; Endothelin-1; Female; Humans; Male; Middle Aged; Postoperative Period; Radioimmunoassay

We here report that aging increases expression of endothelin-1 and NO synthases in the vasculature and kidney of normotensive rats in vivo. Expression of preproendothelin-1 mRNA was quantified by RT-PCR and in situ hybridization, and endothelin-1 protein was determined by radioimmunoassay/HPLC. Vascular mRNA expression of NO synthase isoforms II and III was analyzed by RT-PCR. In young animals, vascular endothelin-1 protein was differentially expressed (aorta < renal artery < carotid artery) and increased with aging in all vascular beds (P < 0.05). In the intact aorta of aged rats, mRNA expression of preproendothelin-1, "inducible" NO synthase II, and endothelial cell NO synthase III gene was up-regulated (P < 0.05). Moreover, preproendothelin-1 mRNA expression increased in glomeruli and tubulointerstitial cells (P < 0.05). To our knowledge this is the first study demonstrating local vascular up-regulation of the trophic factor endothelin under physiological conditions. Activation of vascular endothelin and NO synthases may be important, pressure-independent factors contributing to structural and functional abnormalities of age-dependent diseases, including atherosclerosis.

Topics: Aging; Animals; Arteries; Arteriosclerosis; Endothelin-1; Endothelins; Gene Expression; Humans; In Situ Hybridization; Kidney; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Protein Precursors; Rats; Rats, Inbred WKY; RNA, Messenger

It is known that oxidative stress can be able to induce cytotoxicity of blood cells, stimulate release of inflammatory cytokines, and induce the production of growth factors. The aim of this study was to investigate oxidative stress and endothelial dysfunction in patients with asymptomatic carotid artery disease and healthy controls. Native low-density lipoproteins, oxidised low-density lipoproteins, malondialdehyde, nitrates, glutathione peroxidase activity and endothelin-1 were determined in patients without severe (range between 30% and 50%) carotid artery stenosis. Native low-density lipoproteins, oxidized low-density lipoproteins, malondialdehyde, glutathione peroxydase, and endothelin-1 concentrations were higher in patients than in health controls (P<0.001). No difference was observed in nitrate values (P<0.8). Our results revealed oxidative stress in patients without severe carotid artery stenosis and clinical symptoms. This was shown by the elevated malondialdehyde and oxidized low-density lipoprotein levels.

Topics: Aged; Arteriosclerosis; Biomarkers; Carotid Arteries; Carotid Stenosis; Endothelin-1; Endothelium, Vascular; Female; Glutathione Peroxidase; Humans; Lipoproteins, LDL; Male; Malondialdehyde; Middle Aged; Nitrates; Oxidative Stress; Reference Values; Ultrasonography

The development and progression of atherosclerotic lesions in Watanabe heritable hyperlipidemic rabbits is associated with increases in inducible nitric oxide synthase (NOS2) and endothelin-1 (ET-1) immunoreactivity. In contrast, there is a reduction of immunoreactivity for neuronal NOS (NOS1) in aortic endothelial cells, but no change in endothelial NOS (NOS3) immunoreactivity. However, subendothelial macrophages and smooth muscle showed a different pattern of immunoreactivity of NADPH-diaphorase (NADPH-d), NOS2, ET-1, and NOS1. The lipid-rich macrophages in the intima were positively labeled for NADPH-d, NOS1, NOS2, NOS3, and ET-1. Smooth muscle cells in the subendothelium and the medial layers of the vascular wall were also positive for these markers. These results are consistent with the reduction of endothelium-dependent vasorelaxation that is known to occur during the development and progression of atherosclerosis in familial hypercholesterolemia. The data suggest a key role for vasoactive substances in the development of atherosclerosis.

Topics: Aging; Animals; Animals, Newborn; Aorta, Thoracic; Arteriosclerosis; Cytoplasm; Dihydrolipoamide Dehydrogenase; Endoplasmic Reticulum; Endothelin-1; Hyperlipidemias; Macrophages; Male; Microscopy, Immunoelectron; Mitochondria, Muscle; Muscle Development; Muscle, Smooth, Vascular; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Rabbits; Tunica Intima

Endothelin-converting enzyme (ECE)-1 activates endothelin-1 (ET-1) and may thus contribute to the regulation of vascular tone and cell growth during atherosclerosis.. To evaluate ECE-1 immunoreactivity concerning big ET-1/ET-1, we performed qualitative and quantitative immunohistochemistry in normal internal mammary arteries (n=10), in coronary arteries with adaptive intimal fibrosis (n=10), in aortic fatty streaks (n=10), and in distinct regions of advanced carotid plaques (n=15). Furthermore, we determined ECE-1 activity in the control specimens and in the inflammatory intimal regions of carotid plaques. Double immunolabeling showed that ECE-1 was present in endothelial cells, vascular smooth muscle cells, and macrophages. All ET-1(+) cells were simultaneously ECE-1(+). Most importantly, there were significantly more ET-1(+) cells in the intima and media when atherosclerosis was in an inflammatory stage than when it was in a noninflammatory stage. Moreover, ECE-1 activity was upregulated in the intima of carotid plaques, although immunohistochemically, there were no significant differences between the number of ECE(+) cells in the different compartments of the arterial wall.. Together with ET-1, ECE-1 is abundantly present in human arteries and at different stages of atherosclerotic plaque evolution. The upregulation of the ECE-1/ET-1 system is closely linked to the presence of chronic inflammation and is present in very early stages of plaque evolution. Therefore, enhanced production of active ET-1 may substantially contribute to cell growth and the regulation of vascular tone in advanced atherosclerotic lesions and in the very early stages of plaque evolution, when a plaque is still imperceptible clinically.

Topics: Aorta; Aortic Diseases; Arteriosclerosis; Aspartic Acid Endopeptidases; Carotid Arteries; Carotid Stenosis; Chronic Disease; Coronary Disease; Coronary Vessels; Disease Progression; Endothelin-1; Endothelin-Converting Enzymes; Enzyme Activation; Humans; Immunohistochemistry; Inflammation; Mammary Arteries; Metalloendopeptidases; Tunica Intima; Tunica Media

Nuclear factor kappaB (NF-kappaB) is a transcriptional factor which may be pivotal in the pathogenesis of atherosclerosis. Endothelin-1 (ET-1) is a peptide with proatherogenic properties. We hypothesized that ET-1 may act through activation of NF-kappaB and degradation of IkappaB-alpha, the cytosolic inhibitor of NF-kappaB activation, to create an atherogenic environment. The human monocytic cell line THP-1 was stimulated with ET-1 +/- the ET antagonist, BQ788 and the proteosome inhibitor, PSI. LPS was used as a positive control. Gel shift assays for NF-kappaB activity and Western blot analysis for IkappaB-alpha were performed. Both LPS and ET-1 led to activation of NF-kappaB in nuclear extracts [3.4 +/- 0.45 (LPS) and 2.9 +/- 0.26 (ET-1) fold increase in Arbitrary Densitometric Units (ADU) compared with negative control (P < 0.005 in both cases)]. In the presence of the ETB antagonist, BQ788, NF-kappaB activation was attenuated and not different from control (1.7 +/- 0.24 fold DU compared with negative control; P = NS). In addition, both LPS and ET-1 mediated NF-kappaB activation were attenuated by preincubation with the proteosome inhibitor, PSI (1.3 +/- 0.58 and 1.1 +/- 0.3 fold increase in ADU compared with negative control respectively). Both LPS and ET-1 led to a decrease in the amount of IkappaB-alpha present in the THP-1 cytoplasmic extracts (2.1 +/- 1.5% and 54 +/- 15.7% of ADU vs negative control (P < 0.05). NF-kappaB is activated by ET-1 in human THP-1 monocytes. This data supports a role for the ETs in the development of inflammation in the vessel wall in atherosclerosis.

Topics: Antihypertensive Agents; Arteriosclerosis; Blotting, Western; Cell Line; Cell Nucleus; Cysteine Endopeptidases; Cytoplasm; Cytosol; DNA-Binding Proteins; Endothelin-1; Humans; I-kappa B Proteins; Inflammation; Macrophages; Monocytes; Multienzyme Complexes; NF-kappa B; NF-KappaB Inhibitor alpha; Oligopeptides; Peptides; Piperidines; Proteasome Endopeptidase Complex; Protein Binding

Endothelin (ET)-1 has proatherogenic properties, since ET receptor antagonists reduce atherosclerotic lesions in animals. However, we recently demonstrated that ET-1 and ET(B) receptors are increased in atherosclerotic lesions. To further examine the effects of ET(B) receptor antagonism on atherogenesis, we investigated the chronic effects of the nonselective ET(A)/ET(B) receptor antagonist SB209670 on the development of atherosclerosis in apolipoprotein E (ApoE)-deficient mice.. Ninety-four male mice (10 weeks of age) were randomly divided into four groups: mice fed a Western-type diet or a chow diet with SB209670 treatment (10 mg/kg/day) or placebo for 12 weeks.. In mice fed the Western-type diet, but not in mice fed the chow diet, treatment with SB209670 significantly attenuated the increase in plasma total cholesterol, predominantly in the very-low-density lipoprotein and intermediate-density lipoprotein fractions, without altering the plasma triglyceride level. Furthermore, treatment with SB209670 significantly reduced the extent of aortic atherosclerosis, by 53% in mice fed the Western-type diet and by 38% in mice fed the chow diet. Histological analysis revealed that SB209670 prevented the formation of atheromatous plaque lesions by inhibiting the fibroproliferative process.. We found that chronic administration of SB209670 reduced diet-induced hypercholesterolemia and atherosclerosis in ApoE-deficient mice. Thus, nonselective ET receptor antagonists may have a therapeutic potential in the treatment of human atherosclerotic disease.

Topics: Animals; Aorta; Apolipoproteins E; Arteriosclerosis; Blood Pressure; Cholesterol, Dietary; Cholesterol, VLDL; Diet; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Hypercholesterolemia; Indans; Lipoproteins; Male; Mice; Triglycerides

Xiaoyu tablet, a compound preparation of Chinese herbal medicines, consists of Radix Salviae Miltiorrhizae(SM) and Fructus Crataegi(FC) extracts. To determine whether the proved recipe was reasonable, the effects of Xiaoyu tablet and its component on electrophoretic mobility of serum LDL and expression of ET-1 mRNA and iNOS mRNA of vessel wall in atherosclerotic rabbits were observed. The results indicated that inhibition of expression iNOS mRNA in vessel wall by Xiaoyu tablet was the same as its single extract of SM or FC, but Xiaoyu talbet was superior to SM or FC extract in reduction of electrophoretic mobility of serum LDL and inhibition of ET-1 mRNA expression in vessel wall. These results suggested that there was obvious synergism on prevention and treatment of atherosclerosis when both of the Chinese herbal medicines were simultaneously used.

Topics: Animals; Aorta, Abdominal; Arteriosclerosis; Drug Combinations; Drugs, Chinese Herbal; Endothelin-1; Hypolipidemic Agents; Lipoproteins, LDL; Male; Nitric Oxide Synthase; Phytotherapy; Plant Extracts; Rabbits; RNA, Messenger; Salvia miltiorrhiza; Tablets

One crucial role of endothelium is to keep the innermost surface of a blood vessel antithrombotic. However, the endothelium also expresses prothrombotic molecules in response to various stimuli. The balance between the antithrombotic and prothrombotic nature of the endothelium is lost under certain conditions. During atherosclerosis, the attachment of platelets to the vessel surface has been suggested to promote the proliferation of smooth muscle cells and intimal thickening as well as to affect the prognosis of the disease directly through myocardial infarction and stroke. Dysfunctional endothelium, which is often a result of the action of oxidized low-density lipoprotein (OxLDL), tends to be more procoagulant and adhesive to platelets. Herein, we sought the possibility that the endothelial lectin-like OxLDL receptor-1 (LOX-1) is involved in the platelet-endothelium interaction and hence directly in endothelial dysfunction. LOX-1 indeed worked as an adhesion molecule for platelets. The binding of platelets was inhibited by a phosphatidylserine-binding protein, annexin V, and enhanced by agonists for platelets. These results suggest that negative phospholipids exposed on activation on the surface of platelets are the epitopes for LOX-1. Notably, the binding of platelets to LOX-1 enhanced the release of endothelin-1 from endothelial cells, supporting the induction of endothelial dysfunction, which would, in turn, promote the atherogenic process. LOX-1 may initiate and promote atherosclerosis, binding not only OxLDL but also platelets.

Topics: Animals; Annexin A5; Antibodies; Arteriosclerosis; Blood Platelets; Cattle; CHO Cells; Collagen; Cricetinae; Endothelin-1; Endothelium, Vascular; Humans; Lectins; Lipoproteins, LDL; Phagocytosis; Platelet Activation; Receptors, LDL; Receptors, Oxidized LDL; Scavenger Receptors, Class E; Thrombin

The aim of this study was to investigate vascular endothelin-converting enzyme activity and the tissue level of endothelin-1 in the aorta related to atherosclerotic lesions in high cholesterol diet-fed rabbits. Rabbits were fed two atherogenic diets, 0.5% and 1.5% cholesterol, and a normal diet for 16 weeks. Vascular endothelin-converting enzyme activity in the aortic arch and thoracic aorta was significantly increased (2.0-4.4 times) by the atherogenic diet as compared with the normal diet group as well as the levels of lipids and lipid peroxide in plasma were significantly increased. Tissue endothelin-1 levels in both aortas were also elevated (2.3-6.8 times), corresponding well to the increased tissue enzyme activity. In contrast, plasma endothelin-1 levels increased only in the 1.5% cholesterol diet group (2.7 times). These results indicate that the endothelin-converting enzyme activity and the corresponding endothelin-1 level in the vascular walls increase in association with the development of atherosclerotic lesions.

Topics: Animals; Arteriosclerosis; Aspartic Acid Endopeptidases; Blood Vessels; Endothelin-1; Endothelin-Converting Enzymes; Hyperlipidemias; Isoenzymes; Lipid Peroxides; Lipids; Male; Metalloendopeptidases; Oxidative Stress; Rabbits

In a previous paper we gave evidence that chronic oral defibrotide antagonizes the noxious effect of developing atherosclerosis in the cardiovascular system. In the present paper we give evidence that defibrotide is still capable of exerting beneficial effects on cardiovascular function once atherosclerosis is established. In fact, there was statistically significant amelioration by defibrotide infusion in the following, all of which were hampered by established atherosclerosis: in rabbit aorta relaxation to acetylcholine, prostaglandin E2, and 6-keto-prostaglandin F1alpha generation from rabbit aortas, rabbit heart left ventricular end-diastolic pressure, coronary perfusion pressure, and left ventricular developed pressure, vasopressor activity of acetylcholine and endothelin-1 on coronary perfusion pressure, and 6-keto-prostaglandin F1alpha generation from the rabbit heart. Since prostacyclin takes part in NO generation, is cellular protective, and inhibits 5-lipoxygenase product synthesis, its increase, caused by defibrotide, could explain defibrotide cardioprotective activity. Prostacyclin activity could be backed by prostaglandin E2, another cardioprotective prostaglandin.

Topics: 6-Ketoprostaglandin F1 alpha; Acetylcholine; Animals; Aorta; Arteriosclerosis; Blood Pressure; Body Weight; Cardiovascular Physiological Phenomena; Cholesterol, Dietary; Dinoprostone; Endothelin-1; Fibrinolytic Agents; Heart; In Vitro Techniques; Lipids; Male; Muscle Contraction; Muscle, Smooth, Vascular; Organ Size; Platelet Aggregation Inhibitors; Polydeoxyribonucleotides; Rabbits; Reperfusion; Ventricular Function, Left

Endothelin-converting enzyme-1 (ECE-1) processes big endothelin-1 (ET-1) to ET-1, a peptide implicated in atheroma formation. ECE-1 exists in 2 isoforms (ECE-1alpha and ECE-1beta), the result of alternative splicing of a common gene. Neutral endopeptidase (NEP) is a genetically distinct metallopeptidase that degrades the natriuretic peptides. These peptides mediate antiproliferative and vasodilating actions. We sought to demonstrate the distribution of the 2 ECE-1 isoforms in experimental atherosclerosis, to determine the effects of chronic NEP-I on plasma cGMP concentrations, vascular wall ECE-1 activity, and ET-1 concentration, and to correlate these actions with atheroma formation. Our hypothesis was that chronic NEP-I, in association with augmented cGMP, would inhibit ECE-1 conversion of big ET-1 to active ET-1, thus reducing tissue ET-1 concentrations and associated atheroma formation.. Cholesterol-fed New Zealand White rabbits (n=8, 1% cholesterol diet) and NEP-I-treated cholesterol-fed New Zealand White rabbits (n=8; candoxatril, 30 mg/kg per day, Pfizer) were euthanized after 8 weeks of feeding. ECE-1alpha and ECE-1beta immunoreactivity was present in the aortas of both groups. Compared with control values, plasma cGMP concentrations were increased (2.8+/-0.6 versus 8.4+/-1.2 pmol/mL, P<0.05), ECE-1 activity was attenuated (68+/-3% versus 32+/-8%, P<0. 05), aortic tissue ET-1 concentrations were reduced (4.6+/-0.5 versus 3.2+/-0.3 pg/mg protein, P<0.05), and atheroma formation was attenuated (62+/-6% versus 34+/-5%, P<0.01) by NEP-I.. These studies suggest that ECE-1 is present and functionally active in the vascular wall in atherosclerosis. Inhibition of ECE-1 by NEP-I represents a novel approach to interruption of the endothelin system in this cardiovascular disease state.

Topics: Animals; Aorta; Arteriosclerosis; Aspartic Acid Endopeptidases; Atrial Natriuretic Factor; Chronic Disease; Cyclic GMP; Diet, Atherogenic; Disease Models, Animal; Endothelin-1; Endothelin-Converting Enzymes; Endothelins; In Vitro Techniques; Isoenzymes; Male; Metalloendopeptidases; Neprilysin; Protein Precursors; Rabbits; Time Factors; Vasoconstriction

A comparative analysis of the content of the soluble form of cell adhesion protein P-selectin in the blood plasma of patients with acute myocardial infarction (AMI), massive atherosclerosis (MA) and primary pulmonary hypertension (PPH), investigation of the relationship between plasma content of P-selectin and known markers of platelets and endothelial cells activation, preliminary assessment of the prognostic value of P-selectin determination.. This study included 16 patients with AMI, 20 patients with MA, 21 patients with PPH and 18 healthy donors. The follow-up was 1-5 years. End-points in the group of patients with AMI were recurrent acute coronary syndrome and coronary artery by-pass operation, in the group with MA--thrombotic complications (acute coronary syndrome, ischemic stroke) and in the group with PPH--death. P-selectin was measured by ELISA and platelet factor 4 (PF4), thromboxane B2 (TXB2), endothelin-I and stable prostacyclin metabolite 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) by means of commercial ELISA kits.. Mean level of P-selectin in blood plasma of patients with AMI (1 day) (361 +/- 18 ng/ml), MA (410 +/- 31 ng/ml) and PPH (627 +/- 83 ng/ml) was increased in comparison with the group of healthy donors (269 +/- 12 ng/ml) (everywhere p < 0.001). In AMI, P-selectin was increased on day 1 only, on days 2, 3 and 10-14 of the disease the level of P-selectin was significantly lower than on day 1 and did not differ from the control level in the group of donors. In patients with MA a significant correlation was detected between plasma content of P-selectin and platelet activation marker PF4 (r = 0.606, P = 0.007) and in patients with PPH between the content of P-selectin and another platelet activation marker TXB2 (r = 0.622, p = 0.013). However, no correlation was found in PPH patients between the content of P-selectin and markers of endothelial activation and/or damage (endothelin-1 and 6-keto-PGF1 alpha). Difference in the concentration of P-selectin in patients with or without end-points during the follow-up period was detected in patients with AMI (353 +/- 14 ng/ml and 451 +/- 24 ng/ml, p = 0.009) and PPH (477 +/- 58 ng/ml and 927 +/- 184 ng/ml, p = 0.017) but not with MA (426 +/- 37 ng/ml and 361 +/- 24 ng/ml, p = 0.295).. The level of P-selectin in plasma was increased in patients with acute thrombosis (AMI, 1 day) as well as in patients without clinical signs of thrombosis but with a massive injury of the vasculature (MA and PPH). The increase of P-selectin was, presumably, caused by its secretion from activated platelets since its concentration in plasma correlated with platelet concentration but not endothelial activation markers. Preliminary data indicate that blood plasma soluble P-selectin may be considered as a potential prognostic marker in AMI and PPH.

Topics: 6-Ketoprostaglandin F1 alpha; Adolescent; Adult; Aged; Arteriosclerosis; Biomarkers; Blood Coagulation; Blood Vessels; Endothelin-1; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Myocardial Infarction; P-Selectin; Platelet Activation; Platelet Factor 4; Prognosis; Solubility; Thromboxane B2

Topics: Arteriosclerosis; Biomarkers; Blood Coagulation; Cell Adhesion Molecules; Cytokines; E-Selectin; Endothelin-1; Humans; Inflammation; Intercellular Adhesion Molecule-1; Interleukins; P-Selectin; Stress, Mechanical; Vascular Cell Adhesion Molecule-1

To study the possible role of the human lipid-oxidizing enzyme 15-lipoxygenase (15-LO) in atherosclerosis, we overexpressed it specifically in the vascular wall of C57B6/SJL mice by using the murine preproendothelin-1 promoter. The mice overexpressing 15-LO were crossbred with low density lipoprotein (LDL) receptor-deficient mice to investigate atherogenesis. High levels of 15-LO were expressed in the atherosclerotic lesion in the double-transgenic mice as assessed by immunohistochemistry. The double-transgenic, 15-LO-overexpressing, LDL receptor-deficient mice (LDLR-/-/15LO) developed significantly larger atherosclerotic lesions at the aortic sinus compared with lesions in the LDL receptor-deficient (LDLR-/-) mice after 3 and 6 weeks (107,000 versus 28,000 microm(2) [P:<0.001] and 121,000 versus 87,000 microm(2) [P:<0.05], respectively) of an atherogenic diet. LDL from the LDLR-/-/15LO mice was more susceptible to oxidation than was the LDL from the control LDLR-/- mice, as shown by a shorter lag period for copper-induced conjugated diene formation. On the other hand, no differences were found in the levels of serum anti-oxidized LDL antibodies between the study groups. There were also no differences with respect to the density of macrophages and T lymphocytes infiltrating the lesions in both experimental groups. Taken together, these results support the hypothesis that 15-LO overexpression in the vessel wall is associated with enhanced atherogenesis.

Topics: Animals; Antibodies; Arachidonate 15-Lipoxygenase; Arteriosclerosis; Endothelin-1; Endothelins; Endothelium, Vascular; Lipids; Lipoproteins; Lipoproteins, LDL; Mice; Mice, Transgenic; Oxidation-Reduction; Protein Precursors; Receptors, LDL

The vascular responses to endothelin-1 [ET-1; nonselective endothelin-A and -B (ET(A) and ET(B) agonist)] and sarafotoxin 6c (S6c; ET(B) agonist) were investigated in patients with atherosclerosis. ET-1 and S6c (3, 10 and 30 pmol/min) were infused into the brachial artery while forearm blood flow (FBF) was measured by venous occlusion plethysmography in seven male patients with atherosclerosis and six age-matched healthy male controls. S6c evoked an initial increase followed by a dose-dependent reduction in FBF. The initial dilator component did not differ between the two groups. The vasoconstrictor component of the two lower doses of S6c was significantly larger in the atherosclerotic patients than in controls. The reduction in FBF induced by 3 and 10 pmol/min S6c was 18 +/- 2% and 27 +/- 6% in the control group compared to 29 +/- 3% (p < 0.02) and 42 +/- 2% (p < 0.05) in patients with atherosclerosis. The vasoconstrictor response to S6c correlated with low-density lipoprotein (LDL) cholesterol levels (r = 0.47, p < 0.05). The vasoconstrictor response to ET-1 was similar in the two groups. It is concluded that the forearm vasoconstrictor response to S6c but not that to ET-1 is enhanced in patients with atherosclerosis as compared with healthy controls. This finding suggests an upregulation of vascular smooth muscle ET(B)-receptors in atherosclerosis.

Topics: Aged; Arteriosclerosis; Dose-Response Relationship, Drug; Endothelin-1; Forearm; Humans; Male; Middle Aged; Receptor, Endothelin B; Receptors, Endothelin; Vasoconstriction; Viper Venoms

Endothelin (ET)-1 causes proliferation of vascular smooth muscle cells (VSMC). Although it has been reported that stimulation of ET(B) receptors as well as ET(A) receptors promote proliferation of VSMC, the precise distribution of each receptor subtype in atherosclerotic vessels is unknown. Previous studies demonstrated that apolipoprotein E (apoE)-deficient mice have hypercholesterolaemia and develop severe atherosclerosis. To investigate the pathophysiological roles of vascular ET system in atherosclerosis, we examined preproET-1 messenger ribonucleic acid expression in the aorta of apoE-deficient mice, and performed immunohistochemical staining for ET-1 and each ET receptor subtype (ET(A) and ET(B) receptors) in the atherosclerotic lesions of these mice. The level of preproET-1 mRNA in the aorta was significantly higher in the apoE-deficient mice than in the control mice. Strong ET-1 staining was observed in the macrophage-foam cells, intimal and medial VSMC in the atherosclerotic lesions of the apoE-deficient mice. In addition, in the atherosclerotic lesions, strong ET(B) receptor staining was observed in the macrophage-foam cells, intimal and medial VSMC, which distribution corresponded closely to that of ET-1. ET(A) receptor staining was observed in the medial VSMC of both groups, but not in the macrophage-foam cells of the apoE-deficient mice. ET(A) receptor staining in the medial VSMC was stronger in the apoE-deficient mice than in the control mice. These results suggest that the vascular ET system, including ET-1 and ET receptors, is activated in the atherosclerotic lesions of apoE-deficient mice. Since the distribution of strong ET(B) receptor staining corresponded closely to that of ET-1, it is suggested that the ET system, mediated by ET(B) receptors, has an important role in the pathophysiology of the atherosclerotic lesions of apoE-deficient mice.

Topics: Animals; Aorta, Thoracic; Apolipoproteins E; Arteriosclerosis; Blood Pressure; Endothelin-1; Female; Gene Expression Regulation; Immunohistochemistry; Lipids; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Systole

To study the mechanism of regression of atherosclerosis (AS) by lipanthyl.. Experimental atherosclerotic rabbits created by damaging the abdominal aortic endothelium and feeding with high fat diet for 8 wk were then treated with lipanthyl 15 mg.kg-1.d-1 for 16 wk. Expression of endothelin (ET)-1 mRNA and nitric oxide synthase (NOS) mRNA in atherosclerotic vessel wall was measured by in situ hybridization and reverse transcription polymerase chain reaction (RT-PCR), respectively.. After lipanthyl administration for 16 wk, ET-1 mRNA expression was reduced, and integral optical density (IOD) and area of hybridization granule were observed to be (49,113 +/- 16,868) and (2448 +/- 621) micron 2 in lipanthyl group and (65,188 +/- 10,113) and (3028 +/- 352) micron 2 in atherosclerotic group, respectively. Regarding inducible NOS mRNA expression, IOD and area were decreased by 25.5% and 53.3%, respectively, whereas endothelial NOS mRNA expression was increased.. Restoration of the disturbed ET-1 mRNA/NOS mRNA balance by lipanthyl might be one of its mechanisms leading to regression of atherosclerosis.

Topics: Animals; Aorta, Abdominal; Arteriosclerosis; Endothelin-1; Fenofibrate; Hypolipidemic Agents; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Rabbits; Random Allocation; RNA, Messenger

To investigate the effects of estrogen on serum lipids, plasma endothelin-1(ET-1) and atherosclerosis in ovariectomized(OVX) rabbits.. Forty-five female rabbits were randomly divided into 5 groups, there are 9 in each: group A: normal control; group B: sham operation + cholesterol feeding; group C: OVX + cholesterol feeding; group D: OVX + cholesterol feeding + estradiol benzoate; group E: OVX + cholesterol feeding + estradiol valerate. The OVX rabbits fed with cholesterol were used as a model for atherosclerosis. After fed for 12 weeks, all rabbits were sacrificed, and the levels of serum lipids, plasma ET-1, atherosclerosis plaque of aorta were measured.. (1) Similar with group B, the total cholesterol (TC) of group D and E [(24.95 +/- 5.31) mmol/L and (27.53 +/- 13.18) mmol/L respectively], were significantly decreased as compared with group C which was (37.69 +/- 4.16) mmol/L. (2) The plasma ET-1 level of group C, which was (343.37 +/- 106.10) ng/L, was significantly higher as compared with group D and E, which were (262.19 +/- 36.45) ng/L [symbol: see text] (245.37 +/- 35.76) ng/L respectively. (3) There were no statistically differences of lipidic sedimentation area among group D, E, and B, which were (17.30 +/- 5.44)% and (36.99 +/- 20.29)% and (29.03 +/- 9.67)% respectively. All of them were significantly decreased as compared with group C, which was (74.83 +/- 12.58)%.. Estrogen may improve the serum lipids, decrease the plasma ET-1 level, and prevent the atherosclerosis of ovariectomized rabbits.

Topics: Animals; Arteriosclerosis; Endothelin-1; Estrogens; Female; Lipids; Ovariectomy; Rabbits

Hyperhomocysteinemia is believed to be responsible for the development of vascular disease via several mechanisms, including the impairment of endothelial-cell functionality. In-vitro studies have demonstrated that homocysteine decreases the production or bioavailability of vasodilator autacoids, such as prostacyclin and NO. Here, we show that the treatment of human endothelial cells with noncytotoxic homocysteine concentrations leads to a dose-dependent decrease in both the secretion of the vasoconstrictor agent endothelin-1 (ET-1) and the level of its mRNA. Homocysteine had an inhibitory effect at pathophysiological (0.1 and 0.5 mmol.L(-1)) and pharmacological noncytotoxic (1.0 and 2.0 mmol.L(-1)) concentrations. Mean percentage variation from control for ET-1 production was -36. 2 +/- 18.9% for 0.5 mmol.L(-1) homocysteine and -41.5 +/- 26.8% for 1.0 mmol.L(-1) homocysteine, after incubation for 8 h. Mean percentage variation from control for steady-state mRNA was -17.3 +/- 7.1% for 0.5 mmol.L(-1) homocysteine and -46.0 +/- 10.1 for 1.0 mmol.L(-1) homocysteine, after an incubation time of 2 h. ET-1 production was also reduced by incubation with various other thiol compounds containing free thiol groups, but not by incubation with thiol compounds with no free thiol group. Co-incubation of cells with homocysteine and the sulfhydryl inhibitor N-ethylmaleimide prevented the effect of homocysteine on ET-1 production, confirming a sulfhydryl-dependent mechanism. Based on the reciprocal feedback mechanism controlling the synthesis of vasoactive mediators, these preliminary data suggest a mechanism by which homocysteine may selectively impair endothelium-dependent vasodilation by primary inhibition of ET-1 production.

Topics: Arteriosclerosis; Cell Line; Cell Survival; Dose-Response Relationship, Drug; Endothelin-1; Endothelium, Vascular; Epoprostenol; Homocysteine; Humans; Mercaptoethanol; Nitroso Compounds; S-Nitrosothiols; Time Factors

Studies with mammalian vascular cells have suggested growth inhibitory effects of estrogen on the vascular wall. To investigate the involvement of estrogen receptor-alpha (ER) in the control of endothelial cell proliferation, we have stably transfected human estrogen receptor-alpha cDNA into the endothelial cell line ECV304. The clone ECV-ER, thus obtained, over-expresses estrogen receptor to a level approximately 10-fold higher than the parent cell line. Effects of this over-expression were studied on the cell growth rate, and on the levels of secreted endothelin-1 and vascular endothelial growth factor (VEGF). Similar to the previously reported data in other cell types, we found the transfection of ER in ECV304 cells to be inhibitory to their growth. Our ER-over-expressing clone of ECV304 also showed an inhibition of secreted endothelin-1 and VEGF levels. Moreover, the growth inhibition of this ER-over-expressing clone was reversed by the addition of endothelin-1 or VEGF to the medium. In view of the growth-stimulatory effect of endothelin-1 and VEGF on vascular cells, our results indicate that estrogen receptor-alpha may bring about its growth inhibition partly by suppressing endothelin-1 and/or VEGF production in ECV304 cells.

Topics: Arteriosclerosis; Cell Division; Cell Line; DNA, Complementary; Endothelial Growth Factors; Endothelin-1; Endothelium, Vascular; Estrogen Receptor alpha; Gene Expression Regulation; Humans; Lymphokines; Receptors, Estrogen; Transfection; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Patients with hypertension tend to have a high prevalence of atherothrombotic accidents. Platelet hyperactivity is frequently associated with hypertension. Because the vascular disease associated with hypertension evolves over the years, we investigated platelet activity parameters in a population of older hypertensive patients with no other risk factors for cardiovascular disease.. We studied 34 older, nonsmoking patients (mean age 74 +/- 5 years) with uncomplicated hypertension before and after the normalization of blood pressure (BP) was achieved with the angiotensin-converting enzyme inhibitor quinapril alone or in combination with the Ca2+ antagonist nifedipine.. Platelet aggregation, P-selectin (CD62) expression on the platelet surface, serum levels of Interleukin-1beta (IL-1beta) and of Interleukin-6 (IL-6), as well as plasma levels of soluble P-selectin and Endothelin-1 (ET-1), were analyzed.. All platelet hyperactivity parameters were reduced significantly with the normalization of BP at the end of antihypertensive drug treatment (systolic/diastolic: 186.2 +/- 2.7/103.4 +/- 1.1 mm Hg vs 135.0 +/- 1.3/85.9 +/- 1.9 mm Hg; P < .001). Those factors more strictly associated with endothelium injury, such as ET-1 and IL-6, did not show variations. A significant correlation (Spearman Rank test) was observed among all platelet function parameters and blood pressure values.. This study demonstrated that even in a population of older hypertensive patients with no other risk factor for atherogenic disease, normalization of blood pressure induces a significant reduction of the parameters of enhanced platelet hyperactivity independent of the action exerted, at the platelet level, by the antihypertensive drugs.

Topics: Aged; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Arteriosclerosis; Blood Pressure; Calcium Channel Blockers; Endothelin-1; Female; Humans; Hypertension; Interleukin-1; Interleukin-6; Isoquinolines; Male; Nifedipine; P-Selectin; Platelet Activation; Platelet Aggregation; Prevalence; Prodrugs; Quinapril; Tetrahydroisoquinolines

Endothelin-1 (ET-1), a 21-amino acid vasoactive peptide mainly produced by vascular endothelial cells, is involved in the regulation of vascular tone and smooth muscle cell proliferation. Peroxisome proliferator-activated receptors (PPARs), key players in lipid and glucose metabolism, have been implicated in metabolic disorders that are predisposing to atherosclerosis. Because of the potential role of ET-1 in vascular disorders such as hypertension and atherosclerosis, we investigated the regulation of ET-1 expression by PPAR activators. Western blot and reverse transcription-polymerase chain reaction analyses demonstrated that both PPARalpha and PPARgamma are expressed in human coronary artery endothelial cells as well as in endothelial cell lines such as HMEC-1 and ECV304. In bovine aortic endothelial cells and HMEC-1 cells, both PPARalpha and PPARgamma ligands inhibited thrombin-induced ET-1 secretion, whereas basal ET-1 secretion was only slightly suppressed. Reverse transcription-polymerase chain reaction experiments showed that this inhibition of ET-1 production occurs at the gene expression level. Using transient transfection assays, we demonstrated that PPARs downregulate thrombin-activated transcription of the human ET-1 promoter. Transactivation studies with c-Jun and c-Fos expression plasmids indicated that PPARs negatively interfere with the activator protein-1 signaling pathway, which mediates thrombin activation of ET-1 gene transcription. Furthermore, electrophoretic mobility shift assays demonstrated that PPAR activators reduce the thrombin-stimulated binding activity of bovine aortic endothelial cell nuclear extracts as well as c-Jun binding to an activator protein-1 consensus site. Taken together, these data indicate that (1) both PPARalpha and PPARgamma are expressed in human vascular endothelial cells and (2) PPAR activators inhibit thrombin-induced ET-1 biosynthesis, indicating a novel role for PPARs in vascular endothelial function.

Topics: Animals; Aorta; Arteriosclerosis; Capillaries; Cattle; Coronary Vessels; DNA; Endothelin-1; Gene Expression Regulation; Humans; Peroxisome Proliferators; Promoter Regions, Genetic; Protein Binding; Proto-Oncogene Proteins c-fos; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Thrombin; Transcription Factor AP-1; Transcription Factors; Transcription, Genetic; Transfection

Topics: Arteriosclerosis; Endothelin-1; Humans

This study was designed to analyze the distribution and localization of endothelin-1 (ET-1) and ET receptors (ET(A) and ET(B)) at different stages of human atherosclerotic lesions by immunohistochemistry. Compared with ET(A) receptors, there was increased immunoreactivity of ET-1 and ET(B) receptor in both unfoamy and foamy macrophages and T lymphocytes in fatty streak and fibrous plaque lesions. In addition, medial SMCs located just beneath the foam cell lesions revealed a higher intensity of ET(B) receptor immunoreactivity than those located beneath the normal-looking intima without foam cells. In fibrous plaques, intimal SMCs near foam cells showed an increased density of ET receptors with predominant ET(B) immunoreactivity. In the areas where SMCs showed ET(B) receptor, ET-1 immunoreactivity was also enhanced. These results suggest that accumulation of foamy macrophages and T lymphocytes may modulate the switching of ET receptor subtypes from ET(A) to ET(B) in vascular SMCs. and that the enhanced ET system mediated by ET(B) receptors may play active roles in the progression of atherosclerosis.

Topics: Adolescent; Adult; Aged; Aorta; Arteriosclerosis; Cadaver; Child; Child, Preschool; Culture Techniques; Cytoplasm; Endothelin-1; Female; Foam Cells; Humans; Immunohistochemistry; Macrophages; Male; Middle Aged; Muscle, Smooth, Vascular; Receptor, Endothelin B; Receptors, Endothelin; Sensitivity and Specificity; Severity of Illness Index; T-Lymphocytes

Animal experiments have shown an increase in prepro-endothelin-1 (prepro-ET-1) mRNA expression in the clipped kidney but none in the aortic and mesenteric arteries in 2-kidney, 1-clip Goldblatt hypertensive rats. The present study was aimed at investigating whether plasma and renal endothelin-1 (ET-1) systems are differently activated in patients with renovascular hypertension (RH). The plasma concentration and urinary excretion of ET-1 were measured in 5 patients with RH (before and after successful renal angioplasty), in 7 patients with essential hypertension (EH), and in 8 normotensive control subjects. Immediately before renal angioplasty, plasma samples for ET-1 and plasma renin activity (PRA) measurements were withdrawn from the aorta and both renal veins. Unlike the PRA, the plasma ET-1 concentration did not significantly differ between the involved and the uninvolved sides. The urinary ET-1 excretion level (Fig 1) was markedly increased in patients with RH (30+/-4 ng/g urinary creatinine (UC) vs. 2.5+/-0.2 ng/g UC and 2.6+/-0.5 ng/g UC in control subjects and patients with EH, respectively; P<.001), whereas the plasma ET-1 concentration was normal (0.8+/-0.2 pg/mL vs. 0.65+/-0.3 pg/mL and 0.8+/-0.2 pg/mL in control subjects and EH, respectively, not significant). Renal angioplasty was followed in all patients by normalization of blood pressure and PRA. One week after angioplasty, urinary ET-1 decreased to one fourth of baseline (8.04+/-5.23 ng/g UC, P<.001 vs. values before angioplasty and P<.04 vs. control subjects) and normalized 1 month thereafter (3.13+/-1.62 ng/g UC, not significant vs. control subjects), whereas plasma ET-1 remained steady. The present findings clearly indicate that in patients with RH, urinary ET-1 excretion is increased, whereas plasma ET-1 concentration remains normal. Successful percutaneous transluminal renal angioplasty induced a notable reduction in ET-1 urinary excretion, whereas it did not affect ET-1 plasma concentration.

Topics: Aged; Aldosterone; Angioplasty; Arteriosclerosis; Blood Pressure; Echocardiography; Endothelin-1; Female; Humans; Hypertension, Renal; Male; Middle Aged; Ventricular Function, Left

Topics: Animals; Arteriosclerosis; Endothelin-1; Hypercholesterolemia; Muscle, Smooth, Vascular; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Rabbits

Platelet-activating factor (PAF) is a phospholipid inflammatory mediator which is synthesized by a variety of cells, including monocytes and endothelial cells, and PAF can be retained in activated endothelial cell membranes. Furthermore, PAF-like lipids are produced in other phospholipid membranes as in oxidized LDL. Atherosclerosis is a chronic inflammation in the artery wall, but little is known about the role of immune reactions in the early stages of development of cardiovascular disease. In the present study we investigated if there are antibodies to PAF (aPAF) that may play a role in borderline hypertension and early atherosclerosis.. Seventy-three men with borderline hypertension (BHT) and 73 age-matched normotensive (NT) men (diastolic blood pressure 85-94 and <80 mmHg, respectively) were recruited from a population screening programme. Antibody levels were determined by use of ELISA. Carotid intima-media (IM)-thickness and atherosclerosis was determined by B-mode ultrasonography.. BHT men had 49.3% higher aPAF levels of IgG class than NT controls (P = 0.0007). Antibodies to the biologically inactive lysoPAF did not differ between BHT and NT group. aPAF levels were associated with IM-thickness in the left (P = 0.02) and right (P = 0.009) carotid artery. Furthermore, aPAF levels were enhanced in individuals with the metabolic syndrome (n = 44) as compared to those without (n = 102; P = 0.009), and also significantly associated with insulin levels (P = 0.02) and insulin resistance (P = 0.02).. aPAF antibodies may reflect early vascular changes and thus serve as novel markers for disease, and they may also be pathogenic, by eliciting an inflammatory reaction in the vascular wall.

Topics: Adult; Antibodies; Antibody Specificity; Arteriosclerosis; Blood Pressure; Endothelin-1; Humans; Hypertension; Immunoglobulin G; Insulin-Like Growth Factor Binding Protein 1; Lipoproteins; Male; Middle Aged; Platelet Activating Factor

The aim of this study was to investigate the behaviour of circulating ET-1 in patients with carotid atherosclerosis, before and after carotid thromboendarterectomy (TEA), to test the hypothesis that plasma ET-1 decreases after removal of atherosclerotic lesion. Plasma immunoreactive ET-1 levels were determined in 17 patients with symptomatic and/or hemodynamically significant carotid atherosclerosis on the day before TEA, 48 h and 72 h after surgery and, in 11 of them, also after 8 h and 24 h. Compared to controls, ET-1 levels were significantly higher both before and after TEA; after carotid revascularisation (8 h) ET-1 increased; then, from the 24th h, ET-1 gradually decreased and at the 48th h and 72th h the decrease was significant in front of basal values. The increase of plasma ET-1 in the acute postoperative phase may reflect the degree of surgical stress and manipulation in diseased blood vessels; the following decrease may indicate the improvement of vascular dysfunction in the involved carotid site; the persistence of high ET-1 levels 72 h after surgery could suggest the presence of residual ischemia in the involved district and/or the involvement of other sites in ET-1 production.

Topics: Aged; Arteriosclerosis; Carotid Artery Diseases; Endarterectomy, Carotid; Endothelin-1; Female; Humans; Male

Myocardial ischemia plays a central role in the development of right ventricular failure after acute pulmonary embolism. This study investigates whether pulmonary mediators act specifically on coronary tone and cardiac contractile function in acute pulmonary microembolization and whether such effects are altered in the case of early systemic atherosclerosis. We employ a novel model of serial perfusion in which an isolated rabbit heart is perfused with the effluent of the same animal's isolated lung.. Controlled experiment using isolated organs.. Experimental laboratory.. Male New Zealand White rabbits (controls). Age-matched, male Watanabe rabbits (hypercholesterolemic, development of accelerated atherosclerosis).. Seven isolated control and seven isolated Watanabe hearts were perfused with the saline effluent of the same animal's isolated lung. After the assessment of the baseline data, the lungs were gradually embolized with glass beads measuring 100 microm in diameter to induce an increase in mean pulmonary arterial pressure from 6 to 8 mm Hg, at baseline, up to 25 mm Hg.. Pulmonary embolization to 25 mm Hg evoked a coronary constriction, measured as coronary flow decrease to 89 +/- 7% of the baseline value in controls. In the Watanabe group, coronary constriction was significantly enhanced, compared with controls, with coronary flow decreasing to 76 +/- 6% of the baseline value. In both groups, coronary constriction was followed by a deterioration in cardiac contractile performance. This cardiodepression was significantly deeper in Watanabe hearts with respect to both maximum ventricular pressures and maximum rates of pressure development and decline. Coronary constriction and cardiodepression were prevented by coronary infusion of the nonselective endothelin antagonist PD-145065, the endothelinA antagonists A-127722 and BQ-123, and the endothelin-converting enzyme inhibitor phosphoramidon. Concentration of big endothelin in pulmonary effluent increased from 5.6 +/- 0.3 pmol/L in controls and 5.6 +/- 0.2 pmol/L in the Watanabe group, at baseline, to 8.8 +/- 0.4 pmol/L in controls and 8.9 +/- 0.4 pmol/L in the Watanabe group, at 25 mm Hg pulmonary arterial pressure. Endothelin was not detectable at any time during the experiment in pulmonary effluent. The coronary gradient, calculated as a difference in concentration between coronary and pulmonary effluent, was negative for big endothelin and positive for endothelin in both groups.. We have demonstrated that an increase in pulmonary release of big endothelin occurs during lung embolism, which, in turn, results in coronary constriction and consequent cardiodepression. This action of big endothelin is based on its local coronary conversion into endothelin. In addition, coronary endothelial dysfunction, attributed to early systemic atherosclerosis, was shown to represent a specific risk factor in these events.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arteriosclerosis; Aspartic Acid Endopeptidases; Atrasentan; Coronary Circulation; Endothelin Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Endothelins; Endothelium, Vascular; Glycopeptides; In Vitro Techniques; Male; Metalloendopeptidases; Myocardial Contraction; Oligopeptides; Peptides, Cyclic; Protein Precursors; Pulmonary Embolism; Pyrrolidines; Rabbits; Thromboxane B2; Vasoconstriction

We have determined the ability of the endothelin A (ETA)-selective antagonist PD156707 to block constrictor ET-1 responses in blood vessels from the diseased human heart. ET-1 potently contracted nonatherosclerotic coronary arteries from patients with cardiomyopathy (pD2 = 7.96 +/- 0.15; n = 6), atherosclerotic coronary arteries from patients with ischemic heart disease (pD2 = 8.26 +/- 0.20; n = 4), and saphenous vein grafts that had developed "atherosclerotic" disease after coronary artery bypass (pD2 = 8.41 +/- 0.09; n = 6). PD156707 (100 nM) antagonized the vasoconstrictor response to ET-1 in each of the three preparations, with estimated pA2 values of 7.91 +/- 0.20, 8.05 +/- 0.14, and 8.07 +/- 0.02, respectively. These data suggest that the upregulation of ETB receptors that has been reported in human atherosclerotic coronary arteries does not contribute significantly to the ET-1-mediated constrictor response in these vessels in vitro.

Topics: Adult; Arteries; Arteriosclerosis; Coronary Artery Bypass; Coronary Disease; Coronary Vessels; Dioxoles; Endothelin Receptor Antagonists; Endothelin-1; Female; Humans; In Vitro Techniques; Male; Middle Aged; Receptor, Endothelin A; Saphenous Vein

The precise regulation of cell growth in the vascular wall maintains vascular integrity, and its disruption leads to cardiovascular disorders including atherosclerosis and restenosis. Vascular endothelial growth factor (VEGF) is a specific mitogen for endothelial cells, and endothelin-1 (ET-1) is known to stimulate the proliferation of smooth muscle cells. The aim of this study was to explore a potential interaction between VEGF and ET-1 on each expression in vascular cells. VEGF enhanced preproET-1 mRNA expression and ET-1 secretion in bovine aortic endothelial cells (BAECs). Similarly, in rat vascular smooth muscle cells (VSMCs), ET-1 enhanced VEGF mRNA expression and stimulated VEGF secretion. ET-1-induced VEGF mRNA expression was abolished by a selective ET(A) receptor antagonist, BQ-485, but not by an ET(B)-selective blocker, BQ-788. It was also inhibited by pretreatment with actinomycin D but not by pretreatment with cycloheximide. Furthermore, the actinomycin D chase experiment revealed that ET-1 did not alter VEGF mRNA stability. Coculture of BAECs and VSMCs enhanced both ET-1 and VEGF gene expression in these cells, and the conditioned media from BAECs and VSMCs reproduced the augmentation of each gene expression, which was partially inhibited by BQ-485 or an antibody specific to VEGF. Our results indicate that VEGF and ET-1 have stimulatory interactions on each expression, which may play an important role in concomitant proliferation of endothelial and smooth muscle cells in the vascular wall.

Topics: Animals; Arteriosclerosis; Blotting, Northern; Cattle; Cells, Cultured; Coculture Techniques; Culture Media; Cycloheximide; Dactinomycin; Data Interpretation, Statistical; Endothelial Growth Factors; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Gene Expression; Lymphokines; Muscle, Smooth, Vascular; Nucleic Acid Synthesis Inhibitors; Protein Synthesis Inhibitors; Rats; RNA; RNA, Messenger; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Chronic renal allograft rejection is characterized histologically by transplantation-associated arteriosclerosis and glomerulosclerosis (Tx-AA and Tx-AGS). Recent studies in animal models implicate the mitogenic and pressor actions of endothelin-1 (ET-1) in Tx-AA. In humans, however, a link between elevated ET-1 secretion and Tx-AA or Tx-AGS remains unclear. In this study we analyzed expression of ET-1 in the vasculature of renal transplant patients with chronic or acute rejection and in normal controls.. Renal vascular and glomerular ET-1 was assessed by immunohistochemistry in 12 patients with clinically and histologically defined chronic rejection, in 11 patients with acute rejection, and in 5 normal kidneys. ET-1 staining was also correlated with various clinical parameters and with a morphometric index of neointima formation. ET-1 secretion was measured by ELISA in cultured human vascular cell types treated with T cell- and macrophage-associated cytokines.. We found that renal allografts with chronic rejection and Tx-AA expressed 6.1-fold more ET-1 in the vasculature relative to allografts with acute rejection or to normal kidneys (P < 0.01). In Tx-AA, ET-1 was detected predominantly in the neointima, which contained mostly endothelial cells and smooth muscle cells. A strong positive correlation (r = 0.82, P < 0.01) was observed between vascular ET-1 peptide expression and hypertension in patients with chronic rejection. We also showed that macrophage-associated cytokines, but not T cell-associated cytokines, stimulated ET-1 secretion in human endothelial cells, vascular smooth muscle and mesangial cells.. These results demonstrate that elevated ET-1 in the neointima is associated with Tx-AA and chronic rejection. In addition, these results point to an important role for endothelial dysfunction in chronic renal allograft rejection.

Topics: Adolescent; Adult; Aged; Arteriosclerosis; Cells, Cultured; Cytokines; Endothelin-1; Female; Glomerular Mesangium; Graft Rejection; Humans; Kidney Transplantation; Male; Middle Aged; Muscle, Smooth, Vascular; Transplantation, Homologous

Antibodies to endothelial cells (aECs) and to cardiolipin (aCLs) are implicated in autoimmune diseases like systemic lupus erythematosus vasculitis. Beta2-Glycoprotein 1 (beta2GP1) is a cofactor for aCLs. The present study investigated the possible role of aECs, aCLs, and abeta2GP1 in borderline hypertension.. Seventy-three men with borderline hypertension (BHT) and 73 age-matched normotensive (NT) men (diastolic blood pressure, 85 to 94 and <80 mm Hg, respectively) were recruited from a population screening program. Antibody levels were determined by ELISA. Presence of carotid atherosclerosis was determined by B-mode ultrasonography, and 29 individuals had atherosclerotic plaques. BHT men had significantly higher aEC and abeta2GP1 levels of IgG class than NT control subjects (P=0.029 and P=0.0001, respectively). aEC levels of IgM class were higher in BHT (P=0.012), but not abeta2GP1 levels. There was no correlation between aCL levels and BHT. Individuals with atherosclerotic plaques had significantly higher aEC levels of both IgG (P=0.042) and IgM subclasses (P=0.018) than those without plaques, but no difference was found in aCL and abeta2GP1 levels. Endothelin and aECs of IgM class were significantly associated.. We demonstrate the first evidence of a significant elevation of aEC and abeta2GP1 levels in borderline hypertension. These findings provide a new link between hypertension and atherosclerosis and indicate that humoral immune reactions to the endothelium may play an important role in both conditions.

Topics: Adult; Apolipoproteins; Arteriosclerosis; beta 2-Glycoprotein I; Blood Pressure; Carotid Artery Diseases; Cross Reactions; Endothelin-1; Endothelium, Vascular; Glycoproteins; Humans; Hypertension; Immunoglobulin G; Immunoglobulin M; Insulin-Like Growth Factor Binding Protein 1; Male; Middle Aged; Ultrasonography

This study investigated whether endothelin-1 (ET-1), a potent vasoconstrictor, which also stimulates cell proliferation, contributes to endothelial dysfunction and atherosclerosis. Apolipoprotein E (apoE)-deficient mice and C57BL/6 control mice were treated with a Western-type diet to accelerate atherosclerosis with or without ETA receptor antagonist LU135252 (50 mg/kg/d) for 30 wk. Systolic blood pressure, plasma lipid profile, and plasma nitrate levels were determined. In the aorta, NO-mediated endothelium-dependent relaxation, atheroma formation, ET receptor-binding capacity, and vascular ET-1 protein content were assessed. In apoE-deficient but not C57BL/6 mice, severe atherosclerosis developed within 30 wk. Aortic ET-1 protein content (P < 0.0001) and binding capacity for ETA receptors was increased as compared with C57BL/6 mice. In contrast, NO-mediated, endothelium-dependent relaxation to acetylcholine (56 +/- 3 vs. 99 +/- 2%, P < 0.0001) and plasma nitrate were reduced (57.9 +/- 4 vs. 93 +/- 10 micromol/liter, P < 0.01). Treatment with the ETA receptor antagonist LU135252 for 30 wk had no effect on the lipid profile or systolic blood pressure in apoE-deficient mice, but increased NO-mediated endothelium-dependent relaxation (from 56 +/- 3 to 93 +/- 2%, P < 0.0001 vs. untreated) as well as circulating nitrate levels (from 57.9 +/- 4 to 80 +/- 8.3 micromol/liter, P < 0.05). Chronic ETA receptor blockade reduced elevated tissue ET-1 levels comparable with those found in C57BL/6 mice and inhibited atherosclerosis in the aorta by 31% without affecting plaque morphology or ET receptor-binding capacity. Thus, chronic ETA receptor blockade normalizes NO-mediated endothelial dysfunction and reduces atheroma formation independent of plasma cholesterol and blood pressure in a mouse model of human atherosclerosis. ETA receptor blockade may have therapeutic potential in patients with atherosclerosis.

Topics: Acetylcholine; Animals; Aorta, Thoracic; Apolipoproteins E; Arteriosclerosis; Blood Pressure; Cholesterol; Diet; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Humans; In Vitro Techniques; Lipoproteins; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Muscle, Smooth, Vascular; Nitric Oxide; Nitroprusside; Norepinephrine; Phenylpropionates; Pyrimidines; Receptor, Endothelin A; Species Specificity; Systole; Triglycerides; Vasodilation

To clarify relationships between the (endothelial vasodilatory and vasoconstrictive function) and leukocyte inflammatory mediators in subjects with asymptomatic atherosclerosis, we measured (intraplatelet cyclic 3',5'-guanosine monophosphate [cGMP] and cyclic 3',5'-adenosine monophosphate [cAMP]), plasma endothelin (ET-1), and plasma neopterin in 197 subjects with asymptomatic atherosclerosis (median age 63 years, range 49-69 years). We measured neutrophil protease 4 (NP4), tumor necrosis factor (TNFmu), soluble tumor necrosis factor receptor-1 (sTNFR-1), and neutrophil gelatinase associated lipocalin (NGAL) in 152 of the 197 subjects. Intraplatelet cGMP correlated inversely with plasma ET-1 (r=-0.22; p=0.01), which confirms earlier in vitro data of the inhibitory effect of ET-1 on NO production and/or the cGMP mediated inhibitory effect of NO on ET-1 production. Plasma neopterin as well as NP4 correlated directly with intraplatelet cGMP (r=0.24; p<0.01 and r=0.33; p<0.001, respectively). Intraplatelet cAMP correlated directly with plasma TNFmu (r=0.17; p<0.05) and sTNFR-1 (r=0.20; p<0.05). The relationship between leukocyte derived inflammatory mediators and intraplatelet cyclic nucleotides suggest an antiaggregating effect of leukocytes upon platelets, which may constitute a negative feedback mechanism that inhibits platelet activation during the atherosclerotic inflammatory process.

Topics: Aged; Arteriosclerosis; Blood Platelets; Carotid Artery, Common; Carotid Stenosis; Cyclic AMP; Cyclic GMP; Cytokines; Endothelin-1; Female; Humans; Inflammation; Leukocytes; Male; Middle Aged; Myeloblastin; Neopterin; Platelet Aggregation; Prospective Studies; Risk Factors; Serine Endopeptidases; Ultrasonography

Endothelin-1 (ET-1) is an endothelium-derived vasoactive peptide with mitogenic properties. In vitro, vascular release of ET-1 is increased in response to mechanical stress. The goal of the present study was to examine whether ET-1 is released from human atherosclerotic coronary arteries in vivo in response to mechanical pressure and stretch and to characterize immunoreactivity for ET-1 and its precursor, big ET-1, within the atheromatous plaque.. Circulating ET-1 levels were measured in 20 patients before and after coronary angioplasty for stable angina at three sampling sites: the femoral artery and the coronary artery segments proximal and distal to the lesion dilated. In addition, atheromatous tissue obtained from 20 patients undergoing directional coronary atherectomy for stable angina were analyzed for immunoreactivity for ET-1 and big ET-1. In patients undergoing angioplasty, ET-1 levels in the distal coronary artery increased after balloon dilatation (8.4 +/- 0.9 to 16.4 +/- 2 pg/mL, P < .05); proximal coronary artery and systemic ET-1 levels were unchanged. The degree of mechanical stress applied (product of duration and pressure of balloon inflation) correlated with the change in distal coronary artery ET-1 levels (r = .71, P < .01). Immunoreactivity for big ET-1 and ET-1 was ubiquitous in the extracellular space and the intracellular compartment (macrophages, myointimal cells, myofibroblasts, and endothelial cells) of human coronary atheromatous tissue.. Big ET-1 and ET-1 immunoreactivity is ubiquitous within the intracellular and extracellular compartments of coronary atherosclerotic tissue. ET-1 is released from these sites in response to mechanical stress. These findings support a role for endothelins in the evolution and progression of coronary atherosclerosis in humans.

Topics: Aged; Aged, 80 and over; Angioplasty, Balloon, Coronary; Arteries; Arteriosclerosis; Atherectomy, Coronary; Catheterization; Coronary Vessels; Endothelin-1; Endothelins; Female; Humans; Immunohistochemistry; Male; Middle Aged; Pressure; Protein Precursors; Stress, Mechanical

Topics: Arteries; Arteriosclerosis; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Humans; Vasoconstriction

Endothelin-1 (ET-1) with its well-known vasoconstrictive and mitogenic action and through its interaction with insulin, blood glucose, and lipids might play an important role in the accelerated atherogenic process in diabetes mellitus.. To determine whether ET-1 levels are indicative of macrovascular disease in diabetes mellitus.. In the present cross-sectional study, plasma ET-1 concentrations were measured in members of three groups. The first group consisted of 20 patients (15 men and five women; aged 56.3 +/- 12.5 years) with non-insulin-dependent diabetes mellitus and coronary artery disease, the second group of 20 patients (16 men and four women, aged 56.9 +/- 11.2 years) with coronary artery disease only, and the third group of 10 healthy subjects who served as controls. ET-1 levels were determined by a radioimmunoassay.. The mean plasma ET-1 levels for the three groups were 3.59 +/- 1.88, 4.31 +/- 1.32, and 4.42 +/- 1.01 pmol/l respectively, and there was no statistically significant difference among the groups (P = 0.23). There was also no correlation between the plasma ET-1 concentration and age, sex, body mass index, triglyceride, total cholesterol, high-, low- and very-low density lipoprotein levels, for all groups, and, for the first group, hemoglobin A1c (HbA1c), the duration of diabetes mellitus.. The plasma ET-1 concentration is not elevated in non-insulin-dependent diabetes mellitus patients with macrovascular disease, which might reflect the fact that its action occurs in a paracrine or an autocrine rather than an endocrine fashion and suggests that ET-1 levels are not necessarily indicative of macrovascular disease in diabetes mellitus.

Topics: Aged; Arteriosclerosis; Coronary Disease; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Endothelin-1; Female; Humans; Male; Middle Aged

The relationship between carotid atherosclerosis and plasma endothelin-1 (ET-1) concentration was studied in senile patients with essential hypertension. A total of 212 patients (83 M, 129 F; mean age, 63 years) with essential hypertension (WHO stage I-II), and 109 age-matched control subjects (mean age, 61 years) were enrolled in the study. The maximum thicknesses of the intima-media complex (IMTmax) in the right common carotid artery (CCA) and the right internal carotid artery (ICA) was measured by B-mode ultrasonography, and ET-1 was measured by enzyme immunoassay. ET-1 levels were significantly higher in the hypertensive patients than in the control subjects. In middle-aged patients (35-64 years old), IMTmax values of the ICA in patients with high ET-1 concentrations (ET-1 > or = 1.71 pg/ml) were significantly higher than in patients with normal ET-1 concentrations (ET-1 < 1.71 pg/ml). However, the IMTmax of the CCA did not show a similar correlation. In senile patients (65-83 years old), both the CCA and ICA IMTmax values were significantly higher in patients with high ET-1 concentrations than in those with normal ET-1 concentrations. These results indicate that high ET-1 levels in middle-aged patients with essential hypertension may play a role in the progression of ICA atherosclerosis. High ET-1 levels in senile patients with essential hypertension may cause progression of atherosclerosis in both the ICA and CCA.

Topics: Adult; Aged; Aged, 80 and over; Arteriosclerosis; Carotid Artery Diseases; Endothelin-1; Female; Humans; Hypertension; Male; Middle Aged

The distribution of Endothelin-1 (ET-1), a potent vasoactive peptide, within endothelium of human atherosclerotic arteries was examined using a novel en face immunohistochemical technique. The vast majority of endothelial cells were immunoreactive for ET-1. Staining intensity was increased in areas overlying atherosclerotic plaques, calcified media, fatty streaks and about flow dividers, compared with adjacent regions. Multinucleated 'giant' endothelial cells were more common in regions containing strong ET-1 staining than elsewhere. Clusters of leucocytes (probably monocytes) were frequently observed adhering to the endothelial monolayer but not neighbouring regions of denudation. Occasionally underlying macrophage/foam cells and smooth muscle cells were exposed to the surface and included in the en face (Häutchen) preparation. Smooth muscle cells did not stain for ET-1 while macrophages and the larger foam cells were positive for ET-1. These results support the hypothesis that expression of ET-1, at sites containing atheromatous disease, may be involved in the development of atherosclerosis.

Topics: Aged; Arteries; Arteriosclerosis; Cell Count; Endothelin-1; Endothelium, Vascular; Female; Foam Cells; Gene Expression; Giant Cells; Humans; Macrophages; Male; Middle Aged; Muscle, Smooth, Vascular; Saphenous Vein