Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.23.15 (renin)
35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We review the macroscopic and microscopic anatomy of myocardial disease associated with heart failure (HF) and sudden cardiac death (SCD) and focus on the prevention of SCD in light of its structural pathways. Compared to patients without SCD, patients with SCD exhibit 5- to 6-fold increases in the risks of ventricular arrhythmias and SCD. Epidemiologically, left ventricular hypertrophy by ECG or echocardiography acts as a potent dose-dependent SCD predictor. Dyslipidemia, a coronary disease risk factor, independently predicts echocardiographic hypertrophy. In adult SCD autopsy studies, increases in heart weight and severe coronary disease are constant findings, whereas rates of acute coronary thrombi vary remarkably. The microscopic myocardial anatomy of SCD is incompletely defined but may include prevalent changes of advanced myocardial disease, including cardiomyocyte hypertrophy, cardiomyocyte apoptosis, fibroblast hyperplasia, diffuse and focal matrix protein accumulation, and recruitment of inflammatory cells. Hypertrophied cardiomyocytes express "fetospecific" genetic programs that can account for acquired long QT physiology with risk for polymorphic ventricular arrhythmias. Structural heart disease associated with HF and high SCD risk is causally related to an up-regulation of the adrenergic renin-angiotensin-aldosterone pathway. In outcome trials, suppression of this pathway with combinations of beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, and mineralocorticoid receptor blockers have achieved substantial total mortality and SCD reductions. Contrarily, trials with ion channel-active agents that are not known to reduce structural heart disease have failed to reduce these risks. Device therapy effectively prevents SCD, but whether biventricular pacing-induced remodeling decreases left ventricular mass remains uncertain.
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PMID:Structural pathways and prevention of heart failure and sudden death. 1293 Feb 59

Recent studies suggest that aldosterone may play a larger role than once appreciated in normal physiologic function and cardiovascular disease. Some of the adverse cardiovascular effects that have been described include cardiac and vascular fibrosis, vascular necrosis and inflammation, impaired endothelial function, reduced fibrinolysis, hypertension, left ventricular hypertrophy (LVH), congestive heart failure, and cardiac arrhythmias. In light of these findings, the ability to block the actions of aldosterone has gained increased therapeutic importance. Eplerenone is a selective aldosterone receptor blocker that displays little interaction with androgen and progesterone receptors. Eplerenone has already been approved for the treatment of systemic hypertension and has been evaluated in numerous hypertension subgroups, including patients with low plasma renin activity; diabetes; LVH; uncontrolled blood pressure while receiving monotherapy with angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, calcium channel blockers, or beta-blockers; and in black patients. Results of these trials indicate that eplerenone lowers blood pressure and reduces end-organ damage. Further proof of the therapeutic importance of mineralocorticoid receptor blockade comes from the eplerenone post acute myocardial infarction survival and efficacy study (EPHESUS). In this large-scale clinical outcome trial, eplerenone was shown to reduce total mortality by 15% as well as the combined endpoint of cardiovascular mortality/cardiovascular hospitalization by 13% when administered at a mean of 7.3 days post myocardial infarction to patients with evidence of systolic left ventricular dysfunction and symptoms of heart failure. Eplerenone is well tolerated, with an adverse effect profile comparable to placebo. The advent of selective aldosterone blockers, such as eplerenone, should prove to be of great therapeutic value in hypertension control and prevention of cardiovascular disease and associated end-organ damage.
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PMID:Eplerenone: a selective aldosterone blocker. 1293 Dec 52

Mineralocorticoid receptor (MR) binding is tightly regulated by the enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSDII) which selectively metabolizes glucocorticoids to inactive metabolites, thus allowing for MR activation by aldosterone. To examine whether this enzyme is involved in the pathophysiology of salt-sensitive hypertension, 11beta-HSDII activity and messenger RNA (mRNA) levels were determined in blood vessels of Dahl Iwai salt-sensitive (DS) and salt-resistant (DR) rats. Decreased 11beta-HSDII activity and mRNA levels in mesenteric arteries were observed in 8-week-old DS rats on a high-salt diet, indicating that 11beta-HSDII may play a significant role in salt sensitivity and hypertension. It has been suggested that mineralocorticoids act on blood vessels, leading to increased vasoreactivity and peripheral resistance. We present direct evidence that blood vessels are aldosteronogenic. The production of aldosterone in blood vessels was compared between stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto (WKY) rats. Vascular aldosterone and CYP11B2 mRNA levels were significantly increased in 2-week-old SHRSP versus WKY rats. However, the vascular aldosterone levels in 4- and 9-week-old SHRSP and WKY rats were similar. High sodium intake further increased both blood pressure and vascular aldosterone synthesis in the SHRSPs. Both the local renin-angiotensin-aldosterone system (RAAS) and the vascular 11beta-HSDII level are critically important in the pathophysiology of cardiovascular disorders.
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PMID:Pathophysiological roles of vascular 11beta-hydroxysteroid dehydrogenase and aldosterone. 1294 34

Interruption of the renin-angiotensin-aldosterone system (RAAS) at different levels is target-organ protective in several disease states; however, complete blockade is unlikely to be achieved due to escape mechanisms whenever blockade is attempted, incomplete knowledge of the role of all elements of the RAAS, and lack of pharmacotherapy against some elements that have been shown to contribute to disease states. Aldosterone has been overlooked as a mediator of RAAS escape and a key factor in target-organ injury despite the use of available RAAS blockers. Aldosterone is thought to play a role in the development of hypertension, alteration in vascular structure, vascular smooth muscle hypertrophy, endothelial dysfunction, structural renal injury, proteinuria, left ventricular remodeling, collagen synthesis, and myocardial fibrosis. Aldosterone receptor antagonists have been shown to antagonize all these effects in experimental models. Clinical trials with aldosterone antagonists showed an improvement in survival and left ventricular mass index in patients with congestive heart failure, and a reduction in urinary protein excretion and left ventricular mass index in patients with type 2 diabetes and early nephropathy who developed aldosterone synthesis escape. Consequently, aldosterone receptor antagonists may have specific benefits for reducing target-organ injury, particularly if there is evidence of RAAS escape.
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PMID:RAAS escape: a real clinical entity that may be important in the progression of cardiovascular and renal disease. 1294 34

Mendelian forms of hypertension have delivered a treasure trove of novel genes. To date, the molecular mechanisms of five such syndromes have been largely clarified, including glucocorticoid-remediable aldosteronism, Liddle's syndrome, apparent mineralocorticoid excess, an activating mutation of the mineralocorticoid receptor, and pseudohypoaldosteronism type 2. Each of these conditions features salt sensitivity with increased sodium and volume reabsorption by the kidney and low plasma renin activity. None of the gene loci for these syndromes has been convincingly linked to hypertension in the general population. We are investigating kindreds who have autosomal-dominant hypertension and brachydactyly. Affected persons invariably have both anomalies. The hypertension is severe and results in death at about age 50 years from stroke. The condition resembles essential hypertension, because renin, aldosterone, and norepinephrine responses are normal and no salt sensitivity is present. The response to antihypertensive drugs is general. Another feature is diminished baroreflex sensitivity with markedly impaired blood pressure buffering. Furthermore, the ventrolateral medulla may be compromised in these patients, because neurovascular anomalies are a regular finding. We mapped the gene(s) for this disease to chromosome 12p and narrowed the chromosomal region by studying more affected families. Interestingly, the same locus was recently mapped in Chinese families with essential hypertension. Our 3-centimorgan region contains genes encoding a phosphodiesterase, an ATP-dependent potassium channel, and its regulator the sulfonylurea receptor 2. Screening of the coding regions revealed that none of these candidate genes harbor obvious mutations; however, other genetic mechanisms may nevertheless compromise their function. Our study underscores the importance of regulatory physiology to the understanding of a complex genetic syndrome.
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PMID:Mendelian hypertension with brachydactyly as a molecular genetic lesson in regulatory physiology. 1295 13

Aldosterone is an important and independent target for therapeutic intervention in hypertension and hypertension-related diseases. Its actions, once thought to be limited to the distal convoluted tubule of the kidney, are now recognised to be wide-ranging, including interactions with mineralocorticoid receptors in diverse cardiovascular sites to mediate vascular and myocardial remodelling and dysfunction. The latter are referred as non-epithelial actions. Spironolactone, an aldosterone receptor antagonist, is indicated for the treatment of mineralocorticoid hypertension, but its use is limited by an adverse effect profile that includes not only by hyperkalaemia, but also antiandrogenic and progestational effects resulting from its poor specificity for the aldosterone receptor. Eplerenone is the first selective aldosterone receptor antagonist to be developed and recently gained approval from the US FDA for treatment of systemic hypertension. This was based on studies which demonstrated that eplerenone had a blood pressure-lowering profile that was equivalent to existing antihypertensive agents, was useful for treatment of low-renin and systolic hypertension, maintained utility even as add-on therapy to other antihypertensive agents, and exerted beneficial effects on hypertension-related left ventricular hypertrophy and renal impairment. Perhaps most notably, eplerenone was generally well tolerated, and did not cause the antiandrogenic and progestational adverse effects commonly observed with spironolactone.
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PMID:Aldosterone receptor antagonists for hypertension: what do they offer? 1296 13

The secretion and synthesis of renin as the key regulator of the renin-angiotensin-aldosterone system are directly controlled by ANG II in the sense of a negative feedback. Because we found that renal afferent arterioles including the juxtaglomerular portion express the mineralocorticoid receptor, we aimed to characterize a possible direct effect of aldosterone on renin synthesis and renin secretion at the level of renal juxtaglomerular cells. Aldosterone (100 nM) clearly enhanced renin mRNA levels in primary cultures of mouse juxtaglomerular cells prestimulated with isoproterenol (100 nM) but had no effect on the exocytosis of stored renin. Similarly, in the mouse juxtaglomerular cell line As4.1, aldosterone time and concentration dependently increased renin mRNA abundance and prorenin secretion up to 2.5-fold. Moreover, aldosterone potentiated cAMP-induced renin gene expression in As4.1 cells. The effect of aldosterone was inhibited by spironolactone and was mimicked by corticosteroid hormones but not by sex steroids. Aldosterone had no influence on basal renin promoter activity but increased the renin mRNA half-life about threefold. In summary, these data suggest that aldosterone exerts a direct positive effect on renin gene expression at the cellular level probably by stabilizing renin mRNA.
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PMID:Aldosterone enhances renin gene expression in juxtaglomerular cells. 1458 38

Primary aldosteronism is the most common form of secondary hypertension. The use of aldosterone/plasma renin activity ratio (ARR) as a screening test has elevated its prevalence up to 10% of hypertensive patients. Idiopathic bilateral adrenal hyperplasia and aldosterone-producing adrenal adenoma are the leading causes of primary aldosteronism. Most patients with this conditions are normokalemic and clinically undistinguishable from essential hypertensives. However, they suffer from anticipated and more severe target organ damage than other hypertensives. Thus, being primary aldosteronism a common, specifically treatable and sometimes surgically cured form of hypertension, a prompt diagnosis is necessary and cannot be overlooked. The measurement of ambulatory ARR represents the screening test and should be performed in the majority of hypertensive patients. ARR higher than a set cutoff suggests the need of a confirmatory test for primary aldosteronism, such as intravenous saline load or fludrocortisone suppression test. If inability to suppress aldosterone is demonstrated, the disease is confirmed. The subtype evaluation is based on adrenal imaging (CT scan) and selective adrenal venous sampling. The latter is the gold standard for the diagnosis of a lateralized aldosterone secretion, as typically observed in aldosterone-producing adenomas. Microadenomas are frequently overlooked by adrenal image. If lateralization is confirmed, unilateral adrenalectomy is the reasonable therapeutic option, leading to a significant reduction of blood pressure, if not normotension. If bilateral aldosterone excess is demonstrated, an aldosterone receptor antagonist should be administered. This article reviews and discusses the new data about prevalence, diagnosis and treatment of primary aldosteronism.
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PMID:Recent advances in diagnosis and treatment of primary aldosteronism. 1460 90

Progesterone is more than a progestin. Beyond functions in cycle and pregnancy, progesterone binds with high affinity to the mineralocorticoid receptor (MR) acting as an antagonist, with obvious significance for electrolyte homeostasis, an array of MR-related functions in the circulation as well as in the CNS. Progesterone induces natriuresis at physiological concentrations. Lack of antimineralocorticoid activity with conventional progestins may account for sodium and water retention, minor elevation of blood pressure and "pill hypertension" in susceptible women on oral contraceptives. Ethinylestradiol (EE) contributes to this problem by distinct activation of the renin-angiotensin-aldosterone (RAAS) system. Drospirenone (DRSP: 6beta,7beta,15beta,16beta-dimethylene-3-oxo 17alpha-pregn-4-ene-21,17 carbolactone) is the first synthetic progestin with antialdosterone activity. DRSP and progesterone bind to PR in uterine (affinity of both is about 30% of R5020) and MR in kidney cytosol (affinity about 230 and 100% of aldosterone, respectively). Intrauterine administration of DRSP in silastic tubes induced maximum local progestational effects in rabbits. At systemic subcutaneous (s.c.) administration (McPhail-assay) full endometrial transformation was obtained at 1mg per animal per day. At 1-3mg DRSP per animal per day subcutaneously, pregnancy maintenance after ovariectomy, antiovulatory activity, and antimineralocorticoid activity were seen in the respective assays in rats. The latter activity indicates about eight-fold higher potency than spironolactone. DRSP decreased blood pressure in male hypertensive rats, whereas an increase was noted under conventional progestins. DRSP also prevented hypertension and fetal growth retardation in pregnant rats after L-NAME, an inhibitor of nitric oxide synthase. DRSP has antiandrogenic activity. Feminizing effects were recorded during sexual differentiation in male fetuses at high doses. Powerful antiandrogenic effects were also seen in gonad intact and testosterone substituted castrated male rats. The antiandrogenic potency of DRSP is superior to that of spironolactone but below that of cyproterone acetate. Endometrial transformation, inhibition of ovulation, and antimineralocorticoid, i.e. natriuretic effects and mild antiandrogenic effects were recorded at the same range of oral doses (0.5-4 mg per day) in humans. Combined with EE (3 mg DRSP+30 microg EE), DRSP provides effective inhibition of ovulation and cycle control. Body weight compared to conventional oral contraceptives was reduced. DRSP (3 mg per day+15, 20, or 30 microg ethinyl estradiol per day) prevented the mild increase of blood pressure seen under a conventional levonorgestrel-containing contraceptive and even tended to reduce pretreatment blood pressure. Studies on modulation (i.e. inhibition) of glucocorticoid effects at the MR in the CNS remain an unexplored and interesting area for research.
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PMID:Conception and pharmacodynamic profile of drospirenone. 1466 81

The renin-angiotensin-aldosterone system regulates renal vasomotor activity, maintains optimal salt and water homeostasis, and controls tissue growth in the kidney. However, pathologic consequences can result from overactivity of this cascade, involving it in the pathophysiology of kidney disease. An activated renin-angiotensin-aldosterone system promotes both systemic and glomerular capillary hypertension, which can induce hemodynamic injury to the vascular endothelium and glomerulus. In addition, direct profibrotic and proinflammatory actions of angiotensin II and aldosterone may also promote kidney damage. The majority of the untoward effects associated with angiotensin II appear to be mediated through its binding to the angiotensin II type 1 receptor. Aldosterone can also induce renal injury by binding to its receptor in the kidney. An understanding of this system is important to appreciate that inhibitors of this cascade can reduce the progression of chronic kidney disease in proteinuric disease states. Pharmacologic agents that can interfere with this cascade include angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone receptor antagonists. This paper will provide an overview of the renin-angiotensin system, review its role in kidney disease, examine the renal effects of inhibition of this cascade in experimental animal models, and review clinical studies utilizing renin-angiotensin-aldosterone inhibitors in patients with diabetic and nondiabetic nephropathies.
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PMID:The renin-angiotensin-aldosterone system and the kidney: effects on kidney disease. 1496 55


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