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PubMed1997

[Plasminogen activator inhibitor (PAI-1) and markers of endothelial dysfunction in patients with diabetes mellitus].

The authors examined 25 patients with diabetes mellitus type 2 (NIDDM) without vascular complications, treated by sulphonyl urea preparations, 12 hyperinsulinaemic (HI) non-diabetic subjects and 11 normoinsulinaemic healthy subject s. Patients with NIDDM and HI non-diabetics had significantly elevated PAI-1 levels which correlated with the C-peptide level (r = 0.519, p < 0.001), triacylglycerols (TG) (r = 0.685, p < 0.001), BMI (r = 0.607, p < 0.001) and levels of endothelial markers such as von Willebrand s factor and thrombomodulin (TM). In the group of patients with NIDDM no relationship of PAI-1 and C-peptide was found and a significant correlation was found with TM levels (r = 0.609, p = 0.001) and TG levels (r = 0.476, p = 0.046). The results suggest that the endothelial department has an effect on the regulation of PAI-1 levels in patients with NIDDM.

Adult↗

PubMed1997

[Endothelial dysfunction in cardiovascular diseases: therapeutic implications after coronary angioplasty].

Restenosis remains the principal limitation of coronary angioplasty; its main mechanisms are neointimal hyperplasia and vascular remodeling. The endothelium destroyed at angioplasty will progressively recover the denuded zone. However, dysfunction of this neo-endothelium persists for quite a period and may participate in restenosis by influencing these two components (hyperplasia and remodeling). Several therapeutic strategies are under evaluation to try and accelerate the regeneration of the endothelium and make it functional more rapidly. Increasing available nitric oxide (NO) decreases the hyperplasia and improves endothelial function. Growth factors accelerate the endothelial regeneration and improves its function: the effect on hyperplasia depends on the growth factor used. The angiotensin converting enzyme inhibitors decrease hyperplasia by improving endothelial function. These therapeutic strategies merit evaluation in the clinical setting.

Angioplasty, Balloon, Coronary↗

PubMed2003

Endothelial dysfunction and the metabolic syndrome.

The metabolic syndrome is a highly prevalent multifaceted clinical entity produced through the interaction of genetic, hormonal, and lifestyle factors. A distinctive constellation of abnormalities precedes and predicts the accelerated development of inflammation and coagulation represent emerging risk contributors associated with obesity and insulin resistance, central components of the metabolic syndrome, which act in concert with traditional abnormalities to increase cardiovascular risk. The initiation and progression of atherosclerosis may have its origins in impaired endothelial function that can be detected at the earliest stages of development of the syndrome. The basic elements of the metabolic syndrome and accelerated phase of atherogenesis are often silent partners that present many years before the onset of type 2 diabetes mellitus. The ability to detect and monitor subclinical vascular disease, as a reflection of the multiple factors that contribute to impair arterial wall integrity, holds potential to further refine cardiovascular risk stratification. Noninvasive assessment of vascular health may also aid the clinical decision-making process by guiding therapeutic interventions to optimize vascular protection in the metabolic syndrome.

Arteriosclerosis↗

PubMed2002

Lowering of blood pressure improves endothelial dysfunction by increase of nitric oxide production in hypertensive rats.

To investigate the effects of angiotensin converting enzyme inhibitor (ACE-I) and other antihypertensive agents on the nitric oxide (NO) release during hypertension, seven- and fourteen-week-old SHR and deoxycorticosterone acetate (DOCA)-salt rats were treated with hydralazine, manidipine (Ca antagonist) or quinapril (ACE-I) for 3 weeks to lower blood pressure. Systolic blood pressure (SBP) was measured by the tail cuff method once each week. Endothelial cells (ECs) derived from the descending aorta of the treated rats were cultured and NOx levels in culture media were measured with an NO analyzer based on the Griess reaction. In both SHR and DOCA-salt rats, antihypertensive therapy lowered SBP to levels similar to those of control rats. The only exception was quinapril treatment of DOCA-salt rats. Although NOx release by ECs derived from hypertensive rats was improved by antihypertensive therapy, the effect was most pronounced in SHR treated with quinapril. In addition, restoration of NOx release was much more remarkable in younger SHR. NOx release was significantly higher in DOCA-salt rats treated with quinapril than in control rats without reduction of SBP. These results suggest that lowering blood pressure improves release of NO by ECs during hypertension and that the time at which antihypertensive therapy is started is also important to preserve endothelial function. Furthermore, ACE-I is suggested to protect endothelial function by increasing NO production in addition to lowering blood pressure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2004

Endothelial dysfunction and coronary artery spasm.

Coronary spasm plays an important role in the pathogenesis of not only variant angina but also coronary heart disease in general including acute coronary syndromes. The incidence of coronary spasm in Japanese patients with angina pectoris was about 40%. The total number of patients with angina pectoris increases with old age. The patients' age distribution was relatively younger in the coronary spasm than in the stable effort angina. The vascular endothelium has been reported to be a multifunctional organ whose integrity is essential to normal vascular physiology, and whose dysfunction can be a critical factor in the pathogenesis of vascular disease. Acetylcholine and methacholine cause vasodilation by endothelium-derived relaxing factor when endothelium is functioning normal, whereas they cause vasoconstriction when endothelium is removed or damaged. Coronary spasm can be induced by acetylcholine and methacholine. The patients with coronary spasm may have a disturbance in the endothelial function of the coronary arteries.

Angina Pectoris↗

PubMedDate not supplied

Peroxynitrite and vascular endothelial dysfunction in diabetes mellitus.

Macro and microvascular diseases are the principal causes of morbidity and mortality in patients with type I and II diabetes mellitus. Growing evidence implicates reactive nitrogen species (RNS), such as peroxynitrite (ONOO-), derived from nitric oxide (NO) and superoxide anion (O2*-), are important in diabetes. The mechanisms by which diabetes increases RNS, and those by which RNS modifies vascular function, are poorly understood. The authors recently discovered that physiologically relevant concentrations of ONOO- oxidize the zinc thiolate center in endothelial nitric oxide synthase (eNOS). In active eNOS dimers, a tetracoordinated zinc ion is held by four thiols, two from each 135-kDa monomer. Because it remains partially positively charged, the zinc thiolate center is subject to attack by the ONOO-. This oxidant disrupts the zinc thiolate center, releasing zinc, and oxidizing the thiols. Upon thiol reduction, eNOS dimers dissociate into monomers. This modification of eNOS results in reduced NO bioactivity and enhanced endothelial O2*- production, which reacts with NO, further generating ONOO- (eNOS uncoupling). In addition, the authors' studies also demonstrate that low concentrations of ONOO- selectively nitrate and inactivate prostacyclin synthase (PGIS), which not only eliminates the vasodilatory, growth-inhibiting, antithrombotic, and antiadhesive effects of prostacyclin (PGI2), but also increases release of the potent vasoconstrictor, prothrombotic, growth- and adhesion-promoting agents, prostaglandin H2 (PGH2) and thromboxane A2 (TxA2). In diabetic mice and rats, eNOS is uncoupled resulting in an increased tyrosine nitration of PGIS. The authors' studies indicate that in diabetes the synthetic enzymes of the two major endogenous vasodilators undergo oxidative inactivation by different mechanisms, which are, however, tightly interdependent.

Animals↗

PubMed2003

Glucocorticoid excess induces superoxide production in vascular endothelial cells and elicits vascular endothelial dysfunction.

Glucocorticoid (GC) excess often elicits serious adverse effects on the vascular system, such as hypertension and atherosclerosis, and effective prophylaxis for these complications is limited. We sought to reveal the mechanism underlying GC-induced vascular complications. Responses in forearm blood flow to reactive hyperemia in 20 GC-treated patients were significantly decreased to 43+/-8.9% (mean+/-SEM) from the values obtained before GC therapy (130+/-14%). An administration of vitamin C almost normalized blood flow responses. In human umbilical vein endothelial cells (HUVECs), production of hydrogen peroxide was increased up to 166.5+/-3.3% of control values by 10(-7) mol/L dexamethasone (DEX) treatment (P<0.01). Concomitant with DEX-induced hydrogen peroxide production, intracellular amounts of peroxynitrite significantly increased and those of nitric oxide (NO) decreased, respectively (P<0.01). Immunoblotting analysis using anti-nitrotyrosine antibody showed that peroxynitrite formation was increased in DEX-treated HUVECs. Using inhibitors against metabolic pathways for generation of reactive oxygen species (ROS), we identified that the major production sources of ROS by DEX treatment were mitochondrial electron transport chain, NAD(P)H oxidase, and xanthine oxidase. These findings suggest that GC excess causes overproduction of ROS and thereby perturbs NO availability in the vascular endothelium, leading to vascular complications in patients with GC excess.

Adolescent↗

PubMed1998

Effect of ACE inhibition on endothelial dysfunction in patients with chronic heart failure.

The endothelium controls vascular smooth muscle tone by secreting relaxing and contracting factors. There is a constant release of endothelium-derived relaxing factors(s) (EDRF) under basal conditions. In addition, the endothelium can increase the release of EDRF in response to humoral stimulation by vasoactive substances such as acetylcholine or bradykinin. Under physiological conditions the most important stimulus to the release of EDRF is an increase in blood flow, leading to increased shear stress on endothelial cells. Recent experimental studies have raised the possibility that bradykinin plays an important role in the regulation of vascular tone at rest and during flow-stimulated conditions. Bradykinin is a very potent vasodilator that exerts its vasodilatory actions by causing endothelial release of nitric oxide, prostacyclin and/or endothelium-derived hyperpolarizing factor. Recent studies in humans have demonstrated that bradykinin contributes to the regulation of coronary vascular tone under resting and flow-stimulated conditions. This mechanism has been shown to be important in humans in both peripheral and coronary arteries. Angiotensin-converting enzyme (ACE) inhibitors not only decrease angiotensin II but also increase bradykinin levels, since ACE is identical to kininase II, which degrades bradykinin. The beneficial vascular effects of ACE inhibitors may therefore be related to increased availability of bradykinin. Indeed, we have recently shown that ACE inhibition improves flow-dependent, endothelium-mediated vasodilation and that this beneficial effect is bradykinin-dependent. Our preliminary data also indicate that ACE inhibition improves endothelium-mediated vasodilation in patients with heart failure and coronary artery disease due to an enhanced availability of nitric oxide. These findings suggest that the beneficial vascular effects of ACE inhibition in heart failure may be due in part to improved endothelial function.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Pathophysiology of hypertension during preeclampsia linking placental ischemia with endothelial dysfunction.

Studies over the past decade have provided a better understanding of the potential mechanisms responsible for the pathogenesis of preeclampsia. The initiating event in preeclampsia has been postulated to be reduced uteroplacental perfusion as a result of abnormal cytotrophoblast invasion of spiral arterioles. Placental ischemia is thought to lead to widespread activation/dysfunction of the maternal vascular endothelium that results in enhanced formation of endothelin and thromboxane, increased vascular sensitivity to angiotensin II, and decreased formation of vasodilators such as NO and prostacyclin. These endothelial abnormalities, in turn, cause hypertension by impairing renal-pressure natriuresis and increasing total peripheral resistance. The quantitative importance of the various endothelial and humoral factors in mediating the reduction in renal hemodynamic and excretory function and elevation in arterial pressure during preeclampsia are still unclear. Results from ongoing basic and clinical studies, however, should provide new and important information regarding the physiological mechanisms responsible for the elevation in arterial pressure in women with preeclampsia.

Blood Pressure↗

PubMed2000

Endothelial dysfunctions: common denominators in vascular disease.

The past 20 years have witnessed enormous progress in our understanding of the biology of vascular endothelium and its role in cardiovascular disease. Stemming from the seminal observations of Furchgott, the concept of a continuous regulation of vascular tone by normal endothelium and alterations of such control in disease states has become one of the most enlightening concepts of cardiovascular research. This review covers a few updates on the topic, illustrating selective areas of recent progress in our understanding of endothelial function in the control of leucocyte adhesion, atherogenesis and vascular tone, as well as the alterations that cause and accompany vascular disease.

Arteriosclerosis↗

PubMed2000

Endothelial dysfunctions: common denominators in vascular disease.

Arteriosclerosis↗

PubMed2000

Antioxidants, diabetes and endothelial dysfunction.

While a damaged endothelium is recognised to be a key accessory to diabetic macroangiopathy, awareness is developing that impairments concerning endothelium- and nitric oxide (NO)-dependent microvascular function, may contribute to several other corollaries of diabetes, such as hypertension, dyslipidaemia and in vivo insulin resistance. There are now several reports describing elevations in specific oxidant stress markers in both insulin resistance syndrome (IRS) and diabetes, together with determinations of reduced total antioxidant defence and depletions in individual antioxidants. Such a pro-oxidant environment in diabetes may disrupt endothelial function through the inactivation of NO, resulting in the attenuation of a fundamental anti-atherogenic and euglycaemic vascular influence. Indeed, experimental and clinical data suggest that the supplementation of insulin resistant or diabetic states with antioxidants such as vitamin E, normalises oxidant stress and improves both endothelium-dependent vasodilation and insulin sensitivity. However, the promising potential efficacy of antioxidant therapy in cardiovascular disease and diabetes, in either a primary or secondary preventative role, awaits definitive clinical demonstration.

Animals↗

PubMed2001

Endothelial dysfunction, nitric oxide and platelet activation in hypertensive and diabetic type II patients.

Alterations in the synthesis or enhanced inactivation of nitric oxide (NO) and an increase in endothelin-1 production lead to an imbalance that can induce arterial hypertension. Type II diabetes is characterized by impaired endothelium-dependent vasodilation and vascular disease. NO is produced through L-arginine pathway by three different isoforms of nitric oxide synthase (NOS), an inducible form that can be activated by cytokines such as tumor necrosis factor alpha (TNFalpha). We evaluated NO plasmatic levels, endothelial damage markers such as von Willebrand factor (vWF), platelet activation, soluble P-selectin (sP-Sel), TNFalpha levels, insulinaemia (I), glycosylated haemoglobin (HbA1c), glycaemia and blood pressure in 32 hypertensive diabetic type II patients (Group A), 37 hypertensive patients (Group B) and 35 healthy subjects (Group C) matched in sex, age, body mass index and dietary habits. The level of I was increased in patients compared to the controls and correlated with their NO levels. vWF plasmatic levels were increased in Group A compared to Groups B and C. We also found significant differences in platelet activation among all the groups. In diabetic patients, increased NO levels correlated with TNFalpha, HbA1c and platelet activation showed greater endothelial damage than in Group B. These parameters described a prothrombotic state associated with an insulin resistance state, an increased vWF release, raised sP-Sel and TNFalpha levels and, maybe, low NO bioavailability, which could lead to a higher risk of development of thrombotic events in hypertensive diabetic patients (Group A) than in the hypertensive patients in Group B.

Aged↗

PubMed2003

Endothelial dysfunction precedes C-fiber abnormalities in primary (AL) amyloidosis.

Primary (AL; immunoglobulin light-chain associated) amyloidosis is characterized by the deposition of pathological proteins in the extracellular matrix of tissues and organs. Autonomic and sensory peripheral neuropathy is a common feature of this disorder. The pathogenesis of the neuropathy is poorly defined. The aims of this study were to investigate vascular and neural function in the cutaneous microcirculation of AL amyloidosis patients. Seven patients with AL amyloidosis and controls were studied. Acetylcholine and sodium nitroprusside were iontophoresed into the forearm skin. Endothelial, smooth muscle, and C-fiber-mediated cutaneous blood flow (CuBF) were recorded by laser Doppler flowmetry. Endothelial vasodilation in the forearm skin was attenuated in AL amyloidosis patients (p = 0.007). Maximum endothelium-mediated CuBF in the patient group was reduced (p = 0.047). No group differences could be detected in the C-fiber response or smooth muscle vasodilation (p value not significant). Maximum C-fiber and endothelium-independent CuBF did not differ between the two groups (p value not significant). Early in the disease, AL amyloidosis patients present with impaired endothelial function. At this stage, C-fiber and smooth muscle function are still preserved. These data suggest that endothelial abnormalities precede and may contribute to the pathogenesis of the neuropathy associated with AL amyloidosis.

Adult↗

PubMed2006

Arterial stiffness or endothelial dysfunction as a surrogate marker of vascular risk.

The understanding of the pathophysiology of atherosclerosis has advanced greatly in the past decade. Cardiovascular risk factors increase the likelihood of an adverse event by having a detrimental effect on the blood vessel wall. Abnormal interactions among cholesterol, inflammatory mediators, platelets and the vascular wall lead to atherogenesis and cardiac events. In an effort to better understand this process, develop surrogate end points for clinical trials and, ultimately, better risk stratify individuals, a variety of measures of arterial function have been studied. These include measures of endothelial health and arterial compliance. The current paper reviews the various techniques available for the study of vascular health. While not yet routinely used for clinical care, these measurements provide important insights into the pathophysiology and treatment of atherosclerosis.

Arteries↗

PubMed2000

Endothelial dysfunction and atherosclerosis: endothelin receptor antagonists as novel therapeutics.

Atherosclerosis, a chronic systemic disease of the vasculature with an inflammatory component, is the primary cause of cardiovascular morbidity and mortality in industrialized countries. It is associated with the impairment of endothelium-dependent relaxation in the coronary, systemic circulation due to decreased bioavailability of nitric oxide, and increased release oxygen-derived free radicals, thus promoting vasoconstriction, leukocyte adhesion, thrombosis, inflammation, and cell proliferation. Expression of endothelin (ET)-1, a 21-amino acid peptide and major isoform of the endothelin peptide family, is produced by endothelial, vascular smooth muscle cells, and macrophages and acts through Gi-protein-coupled ET(A) and ET(B) receptors. Endothelin-1 increases in hypercholesterolemia and atherosclerosis in humans and experimental animals. This paper reviews current experimental and clinical evidence for the involvement of ET-1 in atherogenesis. Furthermore, the effects of ET receptor blockade on experimental hypercholesterolemia and atherosclerosis will be discussed. As chronic endothelin blockade inhibits fatty streak formation and improves vascular function in experimental hypercholesterolemia, hypertension, and heart failure, and as it restores nitric oxide (NO)-mediated endothelial function and reduces atheroma formation in animals with atherosclerosis, endothelin receptor blockade may therefore offer a novel approach for the treatment of atherosclerosis and its vascular complications.

Coronary Artery Disease↗

PubMed2006

Alpha1D-adrenoceptor-induced relaxation on rat carotid artery is impaired during the endothelial dysfunction evoked in the early stages of hyperhomocysteinemia.

Hyperhomocysteinemia is a known risk factor for cardiovascular diseases, but the underlying mechanisms of this pathology are complex. We aimed to evaluate the effect of hyperhomocysteinemia in vasorelaxations induced by alpha(1D)-adrenoceptor agonists. Vascular reactivity of rat carotid artery to the alpha-adrenoceptor agonist, phenylephrine, was enhanced in hyperhomocysteinemia. Mechanical removal of endothelium did not modify the carotid responsiveness to phenylephrine, compared to control. Phenylephrine induces endothelium-dependent relaxation, in the presence of 5-methyl urapidil (alpha(1A)-adrenoceptor antagonist). We hypothesised that endothelial-relaxant alpha(1)-adrenoceptors are impaired by hyperhomocysteinemia. Incubation with prazosin (selective alpha(1)-adrenoceptor antagonist) or BMY7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4,5]decane-7, 9-dione dihydrochloride) (selective alpha(1D)-adrenoceptor antagonist), similarly inhibited phenylephrine-induced relaxations in both control and hyperhomocysteinemic carotids. Immunohistochemistry showed enhanced immunoreactivity for eNOS and iNOS in hyperhomocysteinemic rats. In carotid arteries from hyperhomocysteinemic rats there was a decrease in superoxide dismutase activity and enhanced superoxide anion production. We conclude that alpha(1D)-adrenoceptors mediate endothelium-dependent relaxation triggered by phenylephrine in rat carotid artery and affect the final tone. Furthermore, the enhanced phenylephrine-induced contraction in carotid artery due to hyperhomocysteinemia is endothelium-dependent and involves a loss of the inhibitory effect of relaxant alpha(1D)-adrenoceptors by reducing NO biodisponibility.

Adrenergic alpha-Agonists↗

PubMed2005

Haemodynamically significant plaque formation and regional endothelial dysfunction in cholesterol-fed ApoE-/- mice.

Flow-mediated vasodilation is suggested as one of the mechanisms involved in arterial expansive remodelling, which is thought to be a defence mechanism in atherogenesis. In the present study, we tested the hypothesis that lumen obstructive plaque formation is associated with failure of NO (nitric oxide)-dependent vasodilation in conduit vessels. Cardiac function and aortic root flow velocities were assessed using high-resolution echocardiography and two-dimensional-guided pulsed Doppler in ApoE(-/-) (apolipoprotein E-deficient) mice fed a standard or high-cholesterol diet. Endothelial function in the proximal and mid-descending aortic regions was studied using a myograph technique. Flow velocity at the aortic root of cholesterol-fed ApoE(-/-) mice was significantly increased as a result of lumen narrowing, detected via histological analysis. NO-dependent vasodilatory responses were selectively impaired in the atherosclerosis-prone vascular regions in cholesterol-fed ApoE(-/-) mice. In conclusion, consumption of a high-cholesterol diet results in lumen obstructive plaque formation in ApoE(-/-) mice, which significantly alters aortic root haemodynamics. This phenomenon is associated with impaired NO-dependent vasodilation in vessel segments known to be prone to atherosclerosis.

Acetylcholine↗