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

In the effort to explain gender-related differences of the cardiovascular system, the renin-angiotensin system experienced intensive exploration. Indeed, the development of hypertension as well as the progression of coronary artery disease and heart failure have two factors in common: (1) display distinct gender specific characteristics and (2) are enhanced by the renin-angiotensin system. It is therefore interesting to note that data from experimental animals, epidemiological surveys, and clinical investigations suggest that the components of the circulating as well as tissue-based renin-angiotensin system are markedly affected by gender. However, the issue is complicated by counter-regulatory effects of estrogen on the system with the substrate, on one hand, and the processing enzymes as well as the chief receptor, on the other hand. In fact, angiotensinogen is up-regulated particularly by oral administration of estrogen, whereas renin, angiotensin-converting enzyme (ACE), and AT-1 receptor are down-regulated by the hormone. While under well-defined experimental conditions the net effect of estrogen appears to result in suppression of the renin-angiotensin system, the clinical situation may be more complex. The judgment is further complicated by the difficulty in precisely measuring the activity of the system at the tissue level. Moreover, clinically relevant read-outs for the activity of the renin-angiotensin system may be regulated multifactorially or only indirectly affected by the system. Nevertheless, the undisputable, profound biochemical changes in the renin-angiotensin system related to the estrogen status allow speculation that such interaction explains some of the differences in the cardiovascular system of men and women.
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PMID:Renin angiotensin system and gender differences in the cardiovascular system. 1186 Oct 38

Effects of an antagonist of AT-1 receptors for angiotensin-II (Ang-II) irbezantane on the NO-synthase and arginase ways of the metabolism of L-arginine were studied in plasma and erythrocytes of the patients with arterial hypertension. The intensity of the non-oxidative arginase way of L-arginine metabolism in plasma and erythrocytes has been shown to be inhanced at hypertension versus the normotensive patients, while the activity of the alternative oxidative NO-synthase way was reduced. Inhibiting AT-1 receptors for Ang-II with high-affinity antagonist irbezantane normalized the ratio between two alternative ways of L-arginine metabolism through inhibiting the arginase way and reciprocal activating the NO-synthase way both in human plasma and erythrocytes.
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PMID:[Effect of irbesartan, an antagonist of AT-1 receptors for angiotensin II, on L-arginine metabolism in arterial hypertension]. 1212 80

In an earlier study, we found increased NO production and NO synthase (NOS) expression in renal and vascular tissues of prehypertensive and adult spontaneously hypertensive rats (SHR). This study was designed to determine the effects of aging and AT-1 receptor blockade (losartan 30 mg/kg/day beginning at 8 weeks of age) on NO system in this model. Compared to the Wistar Kyoto (WKY) control rats, untreated SHR showed severe hypertension, elevated urinary NO metabolite (NO(chi)) excretion, marked upregulations of renal and vascular eNOS and iNOS proteins, normal renal function and heart weight at 9 weeks of age. Hypertension control with either AT-1 receptor or calcium channel blockade (felodipine 5 mg/kg/day) mitigated upregulation of NOS isoforms in the young SHR. With advanced age (63 weeks), the untreated SHR showed increased proteinuria, renal insufficiency, cardiomegaly, reduced urinary NO(chi) excretion and depressed renal and vascular NOS protein expressions as compared to the corresponding WKY group. AT-1 receptor blockade prevented proteinuria, renal insufficiency, cardiomegaly, and renal and vascular NOS deficiency. Thus, in young SHR, hypertension results in compensatory upregulation of renal and vascular NOS, which can be attenuated by vigorous antihypertensive therapy. With advanced age, untreated SHR exhibit cardiomegaly, renal dysfunction and marked reductions of eNOS and iNOS compared with the aged WKY rats. Hypertension control with AT-1 receptor blockade initiated early in the course of the disease prevents target organ damage and preserves renal and vascular NOS.
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PMID:Effects of aging and AT-1 receptor blockade on NO synthase expression and renal function in SHR. 1237 78

Both angiotensin-converting enzyme (ACE) inhibitors and AT-1 receptor antagonists reduce the effects of angiotensin II, however they may have different clinical effects. This is because the ACE inhibitors, but not the AT-1 receptor antagonists, increase the levels of substance P, bradykinin and tissue plasminogen activator. The AT-1 receptor antagonists, but not the ACE inhibitors, are capable of inhibiting the effects of angiotensin II produced by enzymes other than ACE. On the basis of the present clinical trial evidence, AT-1 receptor antagonists, rather than the ACE inhibitors, should be used to treat hypertension associated with left ventricular (LV) hypertrophy. Both groups of drugs are useful when hypertension is not complicated by LV hypertrophy, and in diabetes. In the treatment of diabetes with or without hypertension, there is good clinical support for the use of either an ACE inhibitor or an AT-1 receptor antagonist. ACE inhibitors are recommended in the treatment of renal disease that is not associated with diabetes, after myocardial infarction when left ventricular dysfunction is present, and in heart failure. As the incidence of cough is much lower with the AT-1 receptor antagonists, these can be substituted for ACE inhibitors in patients with hypertension or heart failure who have persistent cough. Preliminary studies suggest that combining an AT-1 receptor antagonist with an ACE inhibitor may be more effective than an ACE inhibitor alone in the treatment of hypertension, diabetes with hypertension, renal disease without diabetes and heart failure. However, further trials are required before combination therapy can be recommended in these conditions.
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PMID:Angiotensin AT-1 receptor antagonism: complementary or alternative to ACE inhibition in cardiovascular and renal disease? 1243 89

Obesity is closely associated with the metabolic syndrome, a combination of disorders including insulin resistance, diabetes, dyslipidemia, and hypertension. A role for local glucocorticoid reamplification in obesity and the metabolic syndrome has been suggested. The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) regenerates active cortisol from inactive 11-keto forms, and aP2-HSD1 mice with relative transgenic overexpression of this enzyme in fat cells develop visceral obesity with insulin resistance and dyslipidemia. Here we report that aP2-HSD1 mice also have high arterial blood pressure (BP). The mice have increased sensitivity to dietary salt and increased plasma levels of angiotensinogen, angiotensin II, and aldosterone. This hypertension is abolished by selective angiotensin II receptor AT-1 antagonist at a low dose that does not affect BP in non-Tg littermates. These findings suggest that activation of the circulating renin-angiotensin system (RAS) develops in aP2-HSD1 mice. The long-term hypertension is further reflected by an appreciable hypertrophy and hyperplasia of the distal tubule epithelium of the nephron, resembling salt-sensitive or angiotensin II-mediated hypertension. Taken together, our findings suggest that overexpression of 11beta-HSD1 in fat is sufficient to cause salt-sensitive hypertension mediated by an activated RAS. The potential role of adipose 11beta-HSD1 in mediating critical features of the metabolic syndrome extends beyond obesity and metabolic complications to include the most central cardiovascular feature of this disorder.
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PMID:Transgenic amplification of glucocorticoid action in adipose tissue causes high blood pressure in mice. 1284 62

Central actions of angiotensin play an important role in cardiovascular control and have been implicated in the pathogenesis of hypertension and heart failure. One feature of centrally or peripherally administered angiotensin is that the bradycardia in response to an acute pressor effect is blunted. It is unknown whether after central angiotensin this is due partly to increased cardiac sympathetic nerve activity (CSNA). We recorded CSNA and arterial pressure in conscious sheep, at least 3 days after electrode implantation. The effects of intracerebroventricular infusions of ANG II (3 nmol/h for 30 min) and artificial cerebrospinal fluid (CSF) (1 ml/h) were determined. The response to intracerebroventricular hypertonic saline (0.6 M NaCl in CSF at 1 ml/h) was examined as there is evidence that hypertonic saline acts via angiotensinergic pathways. Intracerebroventricular angiotensin increased CSNA by 23 +/- 7% (P < 0.001) and mean arterial pressure (MAP) by 7.6 +/- 1.2 mmHg (P < 0.001) but did not significantly change heart rate (n = 5). During intracerebroventricular ANG II the reflex relation between CSNA and diastolic blood pressure was significantly shifted to the right (P < 0.01). Intracerebroventricular hypertonic saline increased CSNA (+9.4 +/- 6.6%, P < 0.05) and MAP but did not alter heart rate. The responses to angiotensin and hypertonic saline were prevented by intracerebroventricular losartan (1 mg/h). In conclusion, in conscious sheep angiotensin acts within the brain to increase CSNA, despite increased MAP. The increase in CSNA may account partly for the lack of bradycardia in response to the increased arterial pressure. The responses to angiotensin and hypertonic saline were losartan sensitive, indicating they were mediated by angiotensin AT-1 receptors.
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PMID:Stimulation of cardiac sympathetic nerve activity by central angiotensinergic mechanisms in conscious sheep. 1475 46

Angiotensin II (Ang II) is an octapeptide with a central role in cardiovascular homeostasis and actions in several organs including the adrenal gland, kidney, brain, heart, smooth muscle cells and sympathetic nervous system. At these levels it is involved in cellular proliferation and apoptosis, cellular migration, inflammation, synthesis and release of various mediators such as platelet-derived growth factor and endothelin-1) and in the synthesis of extracellular matrix. Traditionally, Ang II was considered a systemic hormone regulating blood pressure, aldosterone release and sodium reabsorption. However, nowadays it is known that this mediator is also formed at the tissue level in the brain, kidney and heart, suggesting local paracrine and autocrine action. At the vascular level, with the exception of renin, all other components of this system are locally produced in vascular adventitia, smooth muscle cells or endothelial cells. In the heart all the components have also been found and their response to humoral, nervous and mechanical stimuli suggests a working local system. Ang II exerts its biological action through two main receptor subtypes: AT-1 and AT-2. The AT-1 receptor is responsible for many of the physiological effects of Ang II in cardiac, vascular, kidney, brain and endocrine cells. Expression of the AT-2 receptor is higher in fetal tissue, especially in mesenchymal tissue (like the tongue, endoderm and diaphragm), decreasing after birth. Its effects are frequently opposite to those mediated bt the AT-1 receptor. Its role in cardiovascular pathophysiology is not yet established. Ang II recruits a complex cascade of intracellular second messengers with different patterns of temporal activation: immediate (in seconds), early (in minutes) and late (in hours). Clinical trials using angiotensin converting enzyme inhibitors (ACEi) and AT-1 receptor antagonists (ARA) have shown improvement in morbidity and mortality in hypertension, congestive heart failure and after myocardial infarction. Although many of the mechanisms underlying these actions are not fully understood, there are no doubts about the beneficial effects of inhibiting this system in the treatment of several cardiovascular diseases.
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PMID:[Renin-angiotensin system and its role in cardiovascular physiopathology and therapy]. 1522 51

Heart failure is highly prevalent in the population with chronic kidney disease. Upon starting dialysis, 37% of patients will have had a previous episode of heart failure, doubling the risk of death. Both systolic and/or diastolic function may be impaired. 15% of patients starting dialysis therapy have systolic dysfunction of the left ventricle. The prevalence of diastolic dysfunction at dialysis inception is unknown, but is likely to be high. Either systolic or diastolic dysfunction can lead to clinically evident congestive heart failure. Hypertension and coronary heart disease are important causes of myocardial dysfunction in end-stage renal disease. Individuals with chronic kidney disease are at a very high risk for the development and progression of cardiovascular disease. The increased risk of cardiovascular disease is due to a higher prevalence of both traditional risk factors as well as nontraditional "uremia-related" risk factors. The prevalence of coronary artery disease (CAD) approaches 40% among patients starting dialysis. About 70-80% of these patients have hypertension. Anaemia is a known risk factor for left ventricular hypertrophy (LVH) and dilatation, heart failure and death. The diagnosis and treatment of heart failure in the patients with chronic kidney disease (CKD) are similar to that recommended for patients without CKD. The potent drugs like ACE-I, AT-1 antagonists, beta-receptor antagonists are the main tools in nowadays treatment of CHF. New therapeutic regiments using natriuretic peptides are being evaluated in clinical settings.
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PMID:Heart failure in patients with chronic kidney disease. 1563 34

Red wine polyphenols (RWPs) have been reported to prevent hypertension and endothelial dysfunction. Several individual RWPs exert estrogenic effects. We analyzed the possible in vivo protective effects on blood pressure and endothelial function of RWPs in female spontaneously hypertensive rats (SHR) and its relationship with ovarian function. RWPs (40 mg/kg by gavage) were orally administered for 5 weeks. Ovariectomized rats showed both increased isoprostaglandin F(2alpha) excretion and aortic superoxide production and reduced relaxant response to acetylcholine and contraction to the endothelial nitric oxide synthase (eNOS) inhibitor l-NAME measured in the aorta but similar blood pressure, as compared with sham-operated rats. Moreover, in ovariectomized rats aortic eNOS expression was unchanged, whereas caveolin-1, angiotensin II receptor (AT)-1, and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits p22(phox) and p47(phox) expression was increased compared with sham-operated rats. In both ovariectomized and sham-operated SHR, RWPs reduced systolic blood pressure, urinary isoprostaglandin F(2alpha) excretion, and aortic O(2)(-) production, improving the endothelium-dependent relaxant response to acetylcholine in SHR. These changes were associated with unchanged aortic eNOS expression, whereas caveolin-1 was increased and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits p22(phox) and p47(phox) expression was reduced. RWPs had no effect on the AT-1 overexpression found in ovariectomized animals. All these results suggest that a chronic treatment with RWPs reduces hypertension and vascular dysfunction through reduction in vascular oxidative stress in female SHR in a manner independent of the ovarian function.
Hypertension 2008 Apr
PMID:Wine polyphenols improve endothelial function in large vessels of female spontaneously hypertensive rats. 1825 8

The expression of the Receptor for Advanced Glycation Endproducts (RAGE) is upregulated at sites of vascular inflammation and plays a crucial role in vessel homeostasis. Soluble RAGE (sRAGE), a truncated soluble form of the receptor, acts as a decoy and prevents the inflammatory response mediated by RAGE activation. sRAGE has recently emerged as a biomarker in several RAGE-mediated vascular disorders, including coronary artery disease, hypertension, diabetic vasculopathy and Kawasaki disease. Given the pivotal role played by RAGE and sRAGE in numerous vascular disorders, there is a growing need to understand how drugs can modulate the RAGE axis in different disease conditions. In this regard, there is evidence to suggest that traditional cardiovascular drugs (statins, thiazolidinediones, ACE-inhibitors, AT-1 receptor antagonists) as well as nutraceuticals (grape seed proanthocyanidin extract) could modulate RAGE expression and circulating sRAGE levels in cardiovascular disease states characterized by enhanced RAGE activation. Additionally, the production of genetically engineered sRAGE may hold promise for targeting the activation of RAGE by proinflammatory ligands in the setting of vascular inflammation. The present review considers current vascular drugs as modulators of the RAGE axis, and highlights future directions in the context of RAGE-directed therapy in cardiovascular disease.
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PMID:Soluble RAGE-modulating drugs: state-of-the-art and future perspectives for targeting vascular inflammation. 1948 31


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