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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activation of renal mechanosensory nerves is enhanced by a high-sodium diet and suppressed by a low-sodium diet. Angiotensin (Ang) II and endothelin (ET)-1 each contributes to the impaired responsiveness of renal mechanosensory nerves in a low-sodium diet. We examined whether stimulation of ETA receptors (Rs) contributes to Ang II-induced suppression of the responsiveness of renal mechanosensory nerves. In anesthetized rats fed a low-sodium diet, renal pelvic administration of the Ang type I receptor (AT1-R) antagonist losartan enhanced the afferent renal nerve activity (ARNA) response to increasing renal pelvic pressure 7.5 mm Hg from 7+/-2% to 15+/-2% and the prostaglandin (PG) E(2)-mediated substance P release from 0+/-1 to 8+/-1 pg/min. Adding the ETA-R antagonist BQ123 to the renal pelvic perfusate containing losartan did not produce any further enhancement of the ARNA response or PGE(2)-mediated release of substance P (17+/-3% and 8+/-1 pg/min). Likewise, renal pelvic administration of BQ123 and BQ123+losartan resulted in similar enhancements of the ARNA responses to increased renal pelvic pressure and PGE(2)-mediated substance P release. In high-sodium-diet rats, pelvic administration of Ang II reduced the ARNA response to increased renal pelvic pressure from 27+/-4% to 8+/-3% and the PGE(2)-mediated substance P release from 9+/-0 to 1+/-1 pg/min. Adding BQ123 to the renal pelvic perfusate containing Ang II restored the increases in ARNA and the PGE(2)-mediated substance P release toward control (27+/-6% and 7+/-1 pg/min). In conclusion, stimulation of ETA-R plays an important contributory role to the Ang II-mediated suppression of the activation of renal mechanosensory nerves in conditions of low-sodium diet.
Hypertension 2007 Jan
PMID:Activation of endothelin-a receptors contributes to angiotensin-induced suppression of renal sensory nerve activation. 1706 May 3

In recent years new therapeutic options have been developed for the management of pulmonary arterial hypertension (PAH). Sitaxsentan is an oral, once daily, highly selective endothelin A receptor antagonist that recently demonstrated a positive effect on functional capacity and haemodynamics of PAH patients. The aim of this study is to evaluate the effect of sitaxsentan in the quality of life (QOL) of PAH patients. Twenty-three patients with idiopathic PAH or PAH associated to collagen vascular diseases were evaluated at baseline and after 16 weeks of treatment with sitaxsentan 100 mg orally, once daily. 6-min walk test distance (6MWD) and QOL questionnaire (QOLQ) (SF-36) were obtained at baseline and at week 16. There was a significant improvement in functional capacity evaluated by 6MWD (472 m vs. 490 m, p = 0.03) and also in the physical component of the QOLQ (p < 0.01). Evaluating each of the domains of the SF-36 QOLQ, those more related to physical capacity presented a significant increase while the domains related to the mental component presented a trend of improvement, without reaching statistical significance. Sitaxsentan improves QOL in patients with PAH mainly through the domains related to functional capacity.
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PMID:Effect of sitaxsentan treatment on quality of life in pulmonary arterial hypertension. 1722 88

Vascular remodeling, rather than vasoconstriction, is believed to account for high vascular resistance in severe pulmonary arterial hypertension (PAH). We have found previously that acute Rho kinase inhibition nearly normalizes PAH in chronically hypoxic rats that have no occlusive neointimal lesions. Here we examined whether Rho kinase-mediated vasoconstriction was also important in a rat model of severe occlusive PAH. Adult rats were exposed to chronic hypoxia ( approximately 10% O(2)) after subcutaneous injection of the vascular endothelial growth factor receptor inhibitor SUGEN 5416. Hemodynamic measurements were made in anesthetized rats after 2 weeks of hypoxia (early group) and 3 weeks of hypoxia plus 2 weeks of normoxia (late group). Both groups developed PAH, with greater severity in the late group. In the early group, intravenous fasudil was more effective than intravenous bradykinin, inhaled NO, or intravenous iloprost in reducing right ventricular systolic pressure. Despite more occlusive vascular lesions, fasudil also markedly reduced right ventricular systolic pressure in late-stage rats. Blood-perfused lungs from late-stage rats showed spontaneous vasoconstriction, which was reversed partially by the endothelin A receptor blocker BQ123 and completely by fasudil or Y-27632. Phosphorylation of MYPT1, a downstream target of Rho kinase, was increased in lungs from both groups of rats, and fasudil (intravenous) reversed the increased phosphorylation in the late group. Thus, in addition to structural occlusion, Rho kinase-mediated vasoconstriction is an important component of severe PAH in SUGEN 5416/hypoxia-exposed rats, and PAH can be significantly reduced in the setting of a severely remodeled lung circulation if an unconventional vasodilator is used.
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PMID:Rho kinase-mediated vasoconstriction is important in severe occlusive pulmonary arterial hypertension in rats. 1733 30

Increased endothelin-1-mediated vasoconstrictor tone has been linked to the etiology of a number of pathologies associated with human aging, including hypertension, congestive heart failure, and coronary artery disease. However, it is currently unclear whether aging, per se, is associated with enhanced endothelin-1 system activity. We hypothesized that endothelin-1 vasoconstrictor activity is greater in healthy older compared with young men and that regular aerobic exercise is an effective intervention for reducing endothelin-1 vasoconstrictor tone in older previously sedentary men. Forearm blood flow (plethysmography) responses to intra-arterial infusion of endothelin-1 (5 pmol/min; for 20 minutes) and selective (BQ-123; 100 nmol/min; for 60 minutes) and nonselective (BQ-123+BQ-788; 100 nmol/min; for 60 minutes) endothelin-1 receptor blockade were determined in 28 healthy, sedentary men: 13 younger (age: 27+/-1 years) and 15 older (age: 62+/-2 years). The vasoconstrictor response to endothelin-1 was significantly blunted ( approximately 65%) in the older versus younger men. In response to BQ-123, resting forearm blood flow increased ( approximately 20%; P<0.05) in the older but not in the younger men. The addition of BQ-788 to BQ-123 did not significantly affect the blood flow responses to BQ-123 in either group. Eight of the 15 older sedentary men completed a 3-month aerobic exercise intervention. After the intervention, the vasoconstrictor response to endothelin-1 was markedly increased (225%; P<0.05), whereas BQ-123 resulted in modest vasoconstriction in the previously sedentary older men. These results demonstrate that endothelin-1-mediated vasoconstrictor tone increases with age in healthy men but can be alleviated with regular aerobic exercise.
Hypertension 2007 Aug
PMID:Endothelin-1 vasoconstrictor tone increases with age in healthy men but can be reduced by regular aerobic exercise. 1757 53

Stroke-prone spontaneously hypertensive rats (SHRSP) often suffer from spontaneous stroke, in part, due to abnormalities in the cerebrovasculature. Here, we investigate the profile of key angiogenic factors and their basic signaling molecules in the brain of SHRSP during the age-dependent stages of hypertension. The profile of VEGF and its receptor, Flk-1, was dependent on age and stage of hypertension (i.e., down regulated at pre-hypertensive and malignant hypertensive stages, but up regulated at typical hypertensive stage), while that of its downstream components, pAkt and eNOS, were down regulated in a time-dependent manner in the frontal cortex of SHRSP compared to age-matched genetic control, normotensive WKY rats. On the other hand, the expression of endothelin-1 and its type A receptor (endothelin ETA receptor) were up regulated, depending on age and stage of hypertension. In contrast, levels of endothelin type B receptor were down regulated. The regional cerebral blood flow decreased during the development of malignant hypertension. Thus, subsequent experiments were designed to investigate whether endothelin-1 receptor antagonism, using endothelin-A/-B dual receptor antagonist SB209670, could normalize the molecular profile of these factors in SHRSP brain. Interestingly, blockage of endothelin-1 receptor restored to normal, levels of cerebral endothelin-1, endothelin ETA receptor and endothelin ETB receptor; VEGF and Flk-1; endothelial nitric oxide synthase (eNOS) and pAkt, in SHRSP, compared to age-matched WKY. Endothelin receptor blocker might be important to prevent the progression in the defect in VEGF and its angiogenic signaling cascade in the pathogenesis of hypertension-induced vascular remodeling in frontal cortex of SHRSP rats.
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PMID:Antagonism of endothelin action normalizes altered levels of VEGF and its signaling in the brain of stroke-prone spontaneously hypertensive rat. 1768 27

Persistent pulmonary hypertension of the newborn (PPHN) occurs in 1-4% of neonates with transposition of the great arteries with intact ventricular septum (TGA/IVS). This association is often lethal. To our knowledge, only eight survivors have been described in the literature, two of whom benefited from extracorporeal membrane oxygenation (ECMO). We report two cases of PPHN complicating a TGA/IVS that were refractory to multiple therapies and resolved 48 hours after initiation of bosentan therapy. Bosentan, an oral dual endothelin-1 receptor antagonist, is a new treatment for pulmonary arterial hypertension that was both effective and safe in these two cases of TGA/IVS with PPHN. To our knowledge, it is the first use of bosentan in newborns.
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PMID:Persistent pulmonary hypertension of the newborn with transposition of the great arteries: successful treatment with bosentan. 1770 Dec 14

Until in the early nineties, pulmonary arterial hypertension (PAH) was a uniformly fatal disease, with a median life expectancy of approximately 2.5 years. Uncontrolled studies showed that a small proportion of patients responded to high-dose calcium channel blockers, retrospective studies supported the use of anticoagulant therapy and heart-lung or lung transplantation remained the only option. In 1996, a 3-month randomised, placebo-controlled trial showed that chronic intravenous epoprostenol (synthetic prostacyclin) improved functional state, exercise capacity, haemodynamics, and even survival in patients with idiopathic PAH. Similar benefits were subsequently reported and extended to all PAH categories, and confirmed with more stable prostacyclin analogues administered subcutaneously (treprostinil), by inhalation (iloprost), or even orally (beraprost). In the early 2000s, two randomised controlled trials showed efficacy of the oral intake of the dual endothelin A/B receptor antagonist bosentan. Two selective endothelin-A receptor antagonists, sitaxsentan and ambrisentan, are being developed. Finally, a randomised controlled trial has established the therapeutic efficacy of phosphodiesterase-5 inhibition with sildenafil, introducing a third signalling pathway to be targeted by the pharmacological treatment of PAH. Another phosphodiesterase-5 inhibitor, tadalafil, is already being evaluated. While all these treatments have markedly improved the lives of PAH patients, they have not offered yet a cure of the disease. Multi-drug approaches are now under evaluation, with more ambitious therapeutic goals. Alternative approaches with stem cells, RhoA-Rho-kinase inhibitors, platelet derived growth factor inhibitors and vasoactive intestinal peptides are being considered.
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PMID:Expert opinion on available options treating pulmonary arterial hypertension. 1792 81

Endothelin plays an important role in the pathogenesis of atherosclerosis. The aim of the study was to evaluate the safety and hemodynamic and metabolic responses to 6 months treatment with atrasentan, the selective endothelin-A receptor antagonist. Seventy-two patients with multiple cardiovascular risk factors and nonobstructive coronary artery disease on coronary angiogram were randomly assigned in a double-blind manner to atrasentan or placebo. Mean aortic blood pressure decreased from 92+/-10 to 80+/-10 mm Hg (P<0.001) in the atrasentan group and did not change in the placebo group (93+/-10 and 92+/-11 mm Hg; P=0.84). The difference between the groups was significant (P<0.001). No effect on heart rate was observed. In a subgroup of patients not treated with angiotensin-converting enzyme inhibitor, creatinine level decreased in the atrasentan versus the placebo group (P=0.011). Fasting glucose (P=0.026), glycosylated hemoglobin level (P=0.041), triglyceride l (P=0.013), lipoprotein-A (P=0.046), and uric acid levels (P=0.048) decreased significantly in the atrasentan group compared with the placebo group. No progression of angiographic coronary disease was observed. The most common adverse effects with atrasentan were nasal stuffiness, headache, and edema. In conclusion, 6 months of treatment with atrasentan results in a reduction of blood pressure and improvement in glucose and lipid metabolism. These findings suggest the beneficial role of atrasentan in the treatment of hypertension and metabolic syndrome.
Hypertension 2008 Sep
PMID:Efficacy and safety of atrasentan in patients with cardiovascular risk and early atherosclerosis. 1869 43

Systemic sclerosis (systemic scleroderma) is a chronic connective tissue disease of unknown etiology that causes widespread microvascular damage and excessive deposition of collagen in the skin and internal organs. Raynaud phenomenon and scleroderma (hardening of the skin) are hallmarks of the disease. The typical patient is a young or middle-age woman with a history of Raynaud phenomenon who presents with skin induration and internal organ dysfunction. Clinical evaluation and laboratory testing, along with pulmonary function testing, Doppler echocardiography, and high-resolution computed tomography of the chest, establish the diagnosis and detect visceral involvement. Patients with systemic sclerosis can be classified into two distinct clinical subsets with different patterns of skin and internal organ involvement, autoantibody production, and survival. Prognosis is determined by the degree of internal organ involvement. Although no disease-modifying therapy has been proven effective, complications of systemic sclerosis are treatable, and interventions for organ-specific manifestations have improved substantially. Medications (e.g., calcium channel blockers and angiotensin-II receptor blockers for Raynaud phenomenon, appropriate treatments for gastroesophageal reflux disease) and lifestyle modifications can help prevent complications, such as digital ulcers and Barrett esophagus. Endothelin-1 receptor blockers and phosphodiesterase-5 inhibitors improve pulmonary arterial hypertension. The risk of renal damage from scleroderma renal crisis can be lessened by early detection, prompt initiation of angiotensin-converting enzyme inhibitor therapy, and avoidance of high-dose corticosteroids. Optimal patient care includes an integrated, multidisciplinary approach to promptly and effectively recognize, evaluate, and manage complications and limit end-organ dysfunction.
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PMID:Systemic sclerosis/scleroderma: a treatable multisystem disease. 1895 73

Systemic sclerosis-related pulmonary arterial hypertension (PAH) is a severe disease affecting about 1000 patients in France. In 2008, all scleroderma patients are screened for PAH by a yearly cardiac Doppler ultrasonography. The pathogenesis of systemic sclerosis-related PAH is poorly known but it seems that besides common arteriolar remodeling (media hypertrophy, intimal thickening, endothelial proliferation), venular lesions suggesting obstructive venous disease and inflammatory lesions may be also be involved. Prostacyclin and analogues, phosphodiesterase-5 inhibitors (sildenafil) and endothelin-1 receptor antagonists are proposed as specific treatments for systemic sclerosis-related PAH. Unlike bosentan, which is non-selective, inhibiting both ETA and ETB receptors, sodium sitaxentan is highly selective for ETA receptors; this could favor pulmonary vasodilation.
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PMID:[Pulmonary arterial hypertension related to systemic sclerosis in 2008]. 1908 Dec 17


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