Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cardiac fibroblasts, as the source of extracellular matrix for the left ventricle, subserve important functions to cardiac remodeling and fibrotic development following myocardial infarction or with pressure-overload cardiac hypertrophy. The fibroblast may be the target cell for angiotensin-converting enzyme inhibitors (ACEI) that are cardioprotective and reverse collagen deposition and remodeling but whose mechanisms of action remain controversial. Because we previously documented phenotypic differences between cardiac fibroblasts from the spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) left ventricle, the present study evaluated whether phenotypic differences also exist in the release of endogenous arachidonic acid metabolites or in the activation of phospholipase D, and the importance of observed differences to the formation of collagen and the mechanism of action of ACEI. The experimental design compared endogenous sources of arachidonic acid with exogenous prelabeling of cells. Angiotensin II stimulated greater arachidonic acid release than bradykinin, and WKY cells were more responsive than SHR. The major prostanoid formed by cardiac fibroblasts was prostaglandin I2 (PGI2), with more prostacyclin production by WKY cells than SHR cells both under nonstimulated conditions and in response to angiotensin II or bradykinin. Beraprost, a PGI2 analogue, was shown to decrease growth rate and DNA synthesis of fibroblasts and to inhibit mRNA expression for collagen types I and III, with SHR cells being less responsive to beraprost than WKY cells. These results potentially implicate eicosanoid metabolism, particularly PGI2, in collagen formation, fibrotic development, and cardiac remodeling, and they imply that the SHR genetic hypertension model may be predisposed to excess cardiac fibrosis.
Hypertension 1997 Nov
PMID:Prostacyclin release by rat cardiac fibroblasts: inhibition of collagen expression. 936 54

Cardiac fibrosis after myocardial infarction and in chronic hypertension involves an increase in the synthesis and deposition of collagen within the myocardium. Angiotensin-converting enzyme (ACE) inhibitors limit hypertrophy and fibrosis; their mechanism of action remains controversial, although kinins have been implicated to play a role. Because both bradykinin and prostaglandins (PG) have been shown to reduce collagen gene expression in cardiac fibroblasts, the goal of this study was to determine whether the bradykinin effect was mediated through enhanced prostaglandin formation by cardiac fibroblasts. Bradykinin increased [3H]arachidonic acid metabolite release 2.3-fold over control and stimulated a dose-dependent increase in 6-keto PGF1alpha (the stable metabolite of PGI2) release from these cells, in which 1 nmol/L bradykinin produced a 4-fold increase in 6-keto PGF1alpha release. Beraprost (a PGI2 analogue) reduced steady-state proalpha1(I) and proalpha1(III) collagen mRNA levels by 35.6+/-6.6% and 34.2+/-10.0%, respectively. Bradykinin-induced reductions in collagen type I and III gene expression were reversed by pretreatment with indomethacin. Our results indicate that one mechanism by which bradykinin modulates collagen biosynthesis via the rabbit cardiac fibroblast involves formation of arachidonic acid metabolites, particularly PGI2. The results of the present study argue that stabilization of endogenous kinins (as by ACE inhibitors) would enhance prostacyclin production and result in the attenuation of collagen gene expression, with potential implications for collagen synthesis and deposition within the myocardium.
Hypertension 1998 Jul
PMID:Bradykinin-induced reductions in collagen gene expression involve prostacyclin. 967 42

Prostanoids have played a prominent role in the treatment of pulmonary arterial hypertension (PAH). Several compounds and methods of administration have been studied: chronic intravenously infused epoprostenol, chronic subcutaneously infused treprostinil, inhaled iloprost, and oral beraprost. Chronic intravenous epoprostenol therapy has had a substantial impact on the clinical management of patients with severe PAH. It improves exercise capacity, hemodynamics, and survival in patients with idiopathic pulmonary arterial hypertension (IPAH). It also improves exercise capacity and hemodynamics in patients with PAH occurring in association with scleroderma. The complexity of epoprostenol therapy (chronic indwelling catheters, reconstitution of the drug, operation of the infusion pump, and others) has led to attempts to develop other prostanoids with simpler modes of delivery. Treprostinil, a stable prostacyclin analogue with a half-life of 3 h, has been developed for subcutaneous delivery. It has beneficial effects on exercise and hemodynamics, which depend somewhat on the dose achieved. This, in turn, is determined by the patient's ability to tolerate the drug's side effects, including pain and erythema at the infusion site. Inhaled iloprost therapy may provide selectivity of the hemodynamic effects to the lung vasculature, thus avoiding systemic side effects. In a randomized and controlled trial, iloprost resulted in improvement in a combined end point incorporating the New York Heart Association functional class, 6-min walk test, and deterioration or death. Beraprost is the first orally active prostacyclin analogue. In the first of two randomized controlled trials, beraprost increased exercise capacity in patients with IPAH, with no significant changes in subjects with associated conditions. Hemodynamics did not change significantly, and no difference in survival was detected between the two treatment groups. The second study showed that beraprost-treated patients had less disease progression at six months and confirmed the results of the previous trial. However, this improvement was no longer present at 9 or 12 months. In conclusion, though treatment with prostanoids is complicated by their generally short half-lives and complicated drug delivery systems, they continue to play an important role in the treatment of PAH.
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PMID:Prostanoid therapy for pulmonary arterial hypertension. 1519 79

2-{4-[(5,6-Diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide (NS-304) is an orally available, long-acting nonprostanoid prostacyclin receptor (IP receptor) agonist prodrug. In a rat model of pulmonary hypertension induced by monocrotaline (MCT), NS-304 ameliorated vascular endothelial dysfunction, pulmonary arterial wall hypertrophy, and right ventricular hypertrophy, and it elevated right ventricular systolic pressure and improved survival. {4-[(5,6-Diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (MRE-269), the active form of NS-304, is much more selective for the IP receptor than are the prostacyclin analogs beraprost and iloprost, which also have high affinity for the EP(3) receptor. To investigate the effect of receptor selectivity on vasodilation of the pulmonary artery, we assessed the relaxant response to these IP agonists in rats. MRE-269 induced vasodilation equally in large pulmonary arteries (LPA) and small pulmonary arteries (SPA), whereas beraprost and iloprost induced less vasodilation in SPA than in LPA. An EP(3) agonist, sulprostone, induced SPA and LPA vasoconstriction, and an EP(3) antagonist attenuated the vasoconstriction. Beraprost showed EP(3) agonism and induced LPA and SPA vasoconstriction, whereas the EP(3) antagonist inhibited this vasoconstriction and enhanced beraprost- and iloprost-induced SPA vasodilation. These findings suggest that the EP(3) agonism of beraprost and iloprost interfered with the SPA vasodilation resulting from their IP receptor agonism. Endothelium removal markedly attenuated the vasodilation induced by beraprost, but not that induced by MRE-269 or iloprost. Moreover, the vasodilation induced by beraprost and iloprost, but not that induced by MRE-269, was more strongly attenuated in LPA from MCT-treated rats than from normal rats. NS-304 is a promising alternative medication for pulmonary arterial hypertension with prospects for good patient compliance.
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PMID:A long-acting and highly selective prostacyclin receptor agonist prodrug, 2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide (NS-304), ameliorates rat pulmonary hypertension with unique relaxant responses of its active form, {4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (MRE-269), on rat pulmonary artery. 1855 31

Portopulmonary hypertension is a complication of chronic liver disease, which has significant effects on survival and prognosis. Although the pathogenesis of pulmonary arterial hypertension has been well known, portopulmonary hypertension is often underestimated in patients with chronic liver disease. Every clinician who manages patients with chronic liver disease complaining of dyspnea should consider portopulmonary hypertension because this disorder requires special treatment. Herein, a 40-year-old woman with liver cirrhosis who complained of dyspnea on exercise is presented. She was diagnosed with portopulmonary hypertension by echocardiography and right-heart catheterization. Beraprost was used to reduce the pulmonary arterial pressure and improve the symptoms. Her symptoms were improved after 2 weeks, and improved symptoms and reduced pulmonary arterial pressure were sustained for 18 months.
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PMID:Successful management of portopulmonary hypertension with beraprost. 2138 99

Prostacyclin (PGI2) is a prostaglandin derived from arachidonic acid in the endothelium and smooth muscle which causes vasodilation, inhibits platelet aggregation, and has anti-inflammatory, anti-thrombotic and anti-proliferative effects. In pulmonary arterial hypertension (PAH), PGI2 levels and PGI2 synthase expression are reduced, contributing to the vasoconstriction and vascular smooth muscle cell proliferation seen in the disease. Based on these findings, PGI2 analogues were developed to target this pathway. Epoprostenol was the first targeted therapy available for treating PAH. Due to the short half-life of this drug, it requires administration via a continuous intravenous infusion, and therefore it carries the risks of central line infections and thrombosis. However, it remains the treatment of choice in patients with severe PAH as it has a proven survival benefit as well as improved functional class and exercise capacity. Subsequently, several other PGI2 analogues have been developed with differing modes of administration and varying degrees of efficacy. Beraprost is an oral PGI2 analogue for which a sustained efficacy has not been demonstrated. Iloprost is a nebulised PGI2 analogue that requires administration six to nine times a day and leads to improved functional class, exercise capacity and haemodynamics. There are inhaled, oral, subcutaneous and intravenous forms of treprostinil. Subcutaneous treprostinil avoids the risks of a continuous intravenous administration; however, this drug can cause intractable pain at the injection site. Selexipag is the new oral non-prostanoid IP prostacyclin receptor agonist that has shown improved haemodynamics and good tolerance in a phase II study. Initial results of the phase III trial are promising. Comparison of the different PGI2 agents is limited by a lack of head-to-head clinical trials. However, the development of PGI2 analogues has improved survival in patients with PAH and remains the main treatment option in advanced disease. While PGI2 analogues have good efficacy in PAH, they are not interchangeable, and their delivery systems have many limitations; in particular, they are associated with significant deleterious consequences. In the future, it is hoped that the elusive goal of developing an effective oral PGI2 analogue will be achieved. This would increase the number of people who could benefit from the treatment while reducing the associated adverse events, and as a result improve the survival and quality of life for these patients.
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PMID:Comparative Safety and Tolerability of Prostacyclins in Pulmonary Hypertension. 2674 8