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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A role of the potent and long-acting vasoconstrictor peptide endothelin (ET)- I in the pathophysiology of chronic human heart failure has been postulated, based upon indirect evidence such as elevated plasma ET-1 levels and their relationship to the degree of haemodynamic impairment. Acute heart failure shares many features of chronic heart failure, albeit in an exaggerated fashion. As both the mixed ETA/ETB-receptor antagonist bosentan and the selective ETA receptor antagonist BQ 123 acutely improved the haemodynamics of chronic heart failure patients, there seems to be good reason to believe that ET-1 receptor antagonism may also be of benefit in the setting of acute heart failure. However, appropriate trials will have to be performed to document the clinical benefit of such an approach. Finally, the question remains open as to whether mixed ET-1 receptor antagonists like bosentan will prove better, worse or equal to antagonists that block the ETA, receptor only.
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PMID:Rationale and perspective of endothelin-1 antagonism in acute heart failure. 1181 79

Endothelin-1 (ET-1) has been found to be one of the most potent vasoconstrictive peptides known, and is therefore considered to be an important factor in diseases such as hypertension, heart failure, pulmonary hypertension, renal diseases, etc. Thus, the development of ET-receptor antagonists may offer a new therapeutic strategy in these fields. In this article, we summarize the method for assessing our compound as a selective ETA-receptor antagonist. Binding assays and in vitro function assays (isolated vessels) were examined for the assessment of in vitro potency, selectivity of the ETA receptor against the ETB receptor, specificity for ET receptors, agonistic activities for ET receptors and the blocking manner of the compound on ET receptors. Chinese hamster ovary (CHO) cells expressing human ET receptors and tissue membrane preparations from both human and animals were used for the binding assays. The specificity of the compound against ET receptors was demonstrated using 116 and 9 receptor binding and enzyme assays, respectively. The agonistic activity and potency of the compound at tissue levels were examined using isolated vessels. We also demonstrated the effect of protein binding on the potency of the compound by adding a physiological concentration of serum albumin to the tissue baths. In vivo potency and features of the compound as a selective ETA-antagonist were confirmed using mice, rats and dogs exogenously treated with ET-1 or big ET-1. We also demonstrated the compound's duration of action and pharmacokinetics in animal models and intact animals, respectively. From these experiments, we found a nonpeptide, potent, orally active and long-lasting, highly selective ETA-receptor antagonist.
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PMID:Methods for assessing endothelin ETA-receptor antagonists in preclinical studies. 1222 43

Endothelin (ET) is a recently discovered 21-amino acid peptide that has potent physiologic and pathophysiologic effects that appear to be involved in the development of heart failure. These include effects on arterial smooth muscle cells that cause intense peripheral vasoconstriction and stimulation of cardiac myocytes and fibroblasts. The latter promotes phenotypic changes in these cells that are consistent with cardiac remodeling. The effects of ET are mediated through interaction with two classes of cell surface receptors. The type A receptor (ET-A) has been associated with vasoconstriction and cell growth while the type B receptor (ET-B) has been associated with endothelial-cell mediated vasodilation and with the release of other neurohormones, such as aldosterone. This review summarizes evidence supporting the potential role of ET in the pathogenesis of heart failure and the available information concerning the use of ET receptor antagonists in treating this condition.
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PMID:Endothelin and endothelin receptor antagonists in heart failure. 1236 88

Three isopeptides of endothelin (ET-1, -2, and -3) exert various actions through stimulation of two sub-types of receptor (ETA and ETB). Vascular endothelial cells produce only ET-1. In addition to its powerful vasoconstrictor action, ET-1 has direct mitogenic actions on cardiovascular tissues, as well as comitogennic actions with a wide variety of growth factors and vasoactive substances. ET-1 also promotes the synthesis and secretion of growth factors and various substances, including extracellular constituents. These effects of endogenous ET-1 would naturally be thought to be concerned with the development and/or aggravation of chronic cardiovascular diseases; e.g., hypertension, pulmonary hypertension, vascular remodeling (stenosis, atherosclerosis), renal failure, and heart failure. A large number of peptide and orally active non-peptide endothelin receptor antagonists have been developed, and utilized to analyze physiological and pathophysiological roles of endogenous ET-1. These antagonists have been shown to exert excellent therapeutic effects in animal models of various kinds of diseases by either acute or chronic treatment. Therapeutic treatment of patients suffering from the above-mentioned cardiovascular diseases with ET-receptor antagonists have also been taking place, and bosentan (ETA/ETB antagonist) was recently approved by the FDA as a formal therapeutic drug for pulmonary hypertension. In this review, perspectives for therapeutic applicability of ET-receptor antagonists will be explored.
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PMID:[New expansion of endothelin research: perspectives for clinical application of endothelin-receptor antagonists]. 1261 54

With recognition of the significant role of the endothelin system in cardiovascular and pulmonary vascular diseases, attention has turned to the therapeutic application of agents that antagonize this system. Three strategies can be employed: dual endothelin receptor (ETA and ETB) antagonism, selective ETA antagonism and inhibition of endothelin-converting enzymes. The first two strategies have been evaluated in late-phase clinical trials, with mixed results. The use of the dual endothelin receptor antagonist bosentan in pulmonary arterial hypertension has been successful. Available data are less compelling, but nonetheless promising, for the use of bosentan in digital ulceration secondary to systemic sclerosis, and tezosentan (another dual receptor blocker) in acute heart failure. Both types of receptor antagonists, however, have been evaluated in systemic hypertension and chronic systolic heart failure and are unlikely to be further developed in these areas. For the treatment of hypertension, their (moderate) efficacy and safety/tolerability profiles appear no more favorable than existing antihypertensive agents. In terms of treatment for chronic heart failure, these agents appear to offer no further benefit over standard therapy for the treatment of chronic heart failure, and in fact, may be associated with poorer outcomes. The complexity of the endothelin system and its diverse roles in multiple disease states will ensure its position as a target for drug development.
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PMID:Current status of endothelin blockade for the treatment of cardiovascular and pulmonary vascular disease. 1274 22

Endothelin-1 (ET-1) is a pleiotropic hormone produced primarily by the endothelium. Synthesis of ET-1 is stimulated by the major signals of cardiovascular stress, such as vasoactive agents (angiotensin II, norepinephrine, vasopressin, and bradykinin), cytokines (e.g., tumor necrosis factor alpha and transforming growth factor beta), and other factors, including thrombin and mechanical stress. ET-1 induces vasoconstriction, is proinflammatory, promotes fibrosis, and has mitogenic potential, important factors in the regulation of vascular tone, arterial remodeling, and vascular injury. These effects are mediated via two receptor types, ETA and ETB. The role ET-1 plays in normal cardiovascular homeostasis and in mild essential hypertension in humans is unclear. However, certain groups of essential hypertensive patients may have ET-1-dependent hypertension, including blacks (subjects of African descent), salt-sensitive hypertensives, patients with low renin hypertension, and those with obesity and insulin resistance. ET-1 has also been implicated in severe hypertension, heart failure, atherosclerosis, and pulmonary hypertension. In all of these conditions, plasma immunoreactive ET levels are elevated and tissue ET-1 expression is increased. Accordingly, it is becoming increasingly apparent that ET-1 plays an important role in cardiovascular disease and in some forms of hypertension in humans. Data from clinical trials using combined ETA-ETB receptor blockers have already demonstrated significant blood-pressure-lowering effects. Thus, targeting the endothelin system may have important therapeutic potential in the treatment of hypertension, particularly by contributing to the prevention of target organ damage and the management of cardiovascular disease.
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PMID:Role of endothelin in human hypertension. 1283 65

Given that circulating ET levels in heart failure, in particular, may reach physiological threshold for coronary constrictor responses, the primary objective of the present review is to consider coronary vessels as an important target for circulating and locally produced endothelin(s). In healthy vessels, ET-1 causes biphasic coronary responses characterized by a transient dilation of large and small arteries followed by a sustained constriction. ETB receptors are pivotal in the early dilation of resistance vessels, whereas dilation of conductance vessels may be a secondary phenomenon triggered by flow increases. Exogenous ET-1 causes coronary constriction almost exclusively through ETA receptor activation. Human and canine large epicardial coronary vessels display significant baseline ET-1 dependent tone in vitro and in vivo, an ETA-dependent process. In contrast, ETB receptors located on smooth muscle cells are apparently less important for producing constrictor responses. NO production may serve as an important counter-regulatory mechanism to limit ET-dependent effects on coronary vessels. Conversely, in a dysfunctional endothelium, the loss of NO may augment ET-1 production and activity. By lifting the ET-dependent burden from coronary vessels, ET receptor blockade should help to ensure a closer match between cardiac metabolic demand and coronary perfusion.
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PMID:Role of ET-1 in the regulation of coronary circulation. 1283 68

Despite major advances in conventional medical therapy, patients with heart failure continue to experience significant morbidity and mortality. Endothelin-1 (ET-1) is a potent vasocontrictor and mitogenic peptide that is activated in heart failure. There is increasing experimental and clinical evidence in support of an important role of ET-1 in the pathophysiology of heart failure. Manipulation of the activity of ET-1, especially using endothelin receptor blockers, has allowed for the further elucidation of the role of this neurohormonal system and development of novel therapeutic strategies in heart failure. Published clinical studies of these agents to date have involved relatively small numbers of patients with severe heart failure, followed for a relatively short period of time, and have mainly examined surrogate endpoints. Large-scale trials that address to hard clinical outcomes are ongoing and their results forthcoming. A key question that remains concerns whether selective ETA or dual ETA-ETB receptor blockade will be more effective.
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PMID:Role of endothelins in congestive heart failure. 1283 70

Immediately after an acute myocardial infarction (AMI) or in models of ischemia-reperfusion injury, cardiac endothelin (ET) system is markedly activated, and plasma levels of ET are increased. In the heart, expression of the main components of the ET system (ET-1 peptide, both receptor subtypes ETA and ETB, though not endothelin converting enzyme) are increased both at the gene level and protein level, in the viable myocardium, and--even more substantially--in the necrotic area. Despite these conspicuous abnormalities, the role of ET in this setting remains unclear. In the absence of human data, most short-term studies in animals (in terms of hours to up to 8 days post-AMI) and in the reperfused ischemic heart, have found beneficial effects of ET receptor blockade on survival rate, incidence of arrhythmias, cardiac function, and morphology. In contrast, many studies in which a long-term ET inhibition was started immediately post-infarction and the late effects were examined in animals with ensuing chronic heart failure (14-100 days postinfarction), adverse effects were also observed, such as scar thinning, further ventricular dilation, or even a worse survival rate. It appears that the ET system plays a dual role during the early post-AMI period. At present, it is not clear whether the short-term beneficial effects or long-term adverse effects of ET receptor blockade would prevail. Acute use of short-acting ET receptor antagonists in patients with AMI complicated by an acute heart failure is an attractive possibility that also remains to be investigated.
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PMID:The endothelin system and its role in acute myocardial infarction. 1283 71

Circulating endothelin (ET) levels are elevated in heart failure and positively correlated with severity of heart failure. Recent studies demonstrated arginine vasopressin (AVP) V2 mRNA expression was upregulated in the inner medullary collecting duct (IMCD) of cardiomyopathic hamsters (CM). The goal of the present studies was to determine if ET-1 is involved in upregulating the expression of AVP V2 mRNA in the IMCD of CM by using a mixed ETA/ETB receptor antagonist bosentan. Our results showed plasma ET-1 levels increased in CM hamsters and related with the severity of heart failure. The competitive reverse-transcriptase polymerase chain reaction (RT-PCR) method was used to quantify the expression of AVP V2 and aquaporin 2 (AQP2) mRNA in the IMCD. AVP V2 mRNA expression was elevated in placebo-treated CM hamsters and decreased significantly with 14 days of bosentan treatment. Similar results were seen with AQP2 mRNA. The effect of bosentan in normalizing the expression of AVP V2 and AQP2 mRNA in the IMCD of CM was confirmed by in situ hybridization studies. Bosentan treatments reduced the intensitites of the signals in the IMCD of CM hamsters to that seen in normal hamsters. This study demonstrated that AVP V2 and AQP2 mRNA are upregulated in CM hamsters and these upregulations are attenuated by bosentan treatment, suggesting that ET-1 plays a role in upregulating the expression of AVP V2 mRNA in CM hamsters.
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PMID:Attenuation of renal vasopressin V2 receptor upregulation by bosentan, an ETA/ETB receptor antagonist. 1450 20


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