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Query: UMLS:C0018801 (
heart failure
)
72,216
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
OPC-18790 is a vesnarinone analog currently in clinical trials for treatment of
heart failure
. In vitro studies have shown that, in addition to its positive inotropic actions, OPC-18790 prolongs cardiac action potentials. Therefore, in this study, the effects of OPC-18790 on cardiac potassium currents were compared with those we previously observed for the blockers quinidine and dofetilide in two test systems, i.e., L-cells stably transfected with mammalian cardiac potassium channel clones (Kv1.4, Kv1.5 and Kv2.1) and mouse
AT-1
cells, in which the rapidly inactivating component of the cardiac delayed rectifier (I(Kr)) is the major repolarizing current. In L-cells, 10 to 100 microM OPC-18790 reduced Kv1.4, Kv1.5 and Kv2.1 currents by <30%, whereas quinidine was a more potent blocker (EC50 < 10 microM) and the I(Kr)-specific blocker dofetilide was without effect. In contrast, in
AT-1
cells, OPC-18790 blocked I(Kr) with an EC50 (0.96 +/- 0.12 microM, n = 10) similar to that of quinidine (0.9 +/- 0.2 microM). For both drugs, block was voltage dependent, increasing at positive potentials. OPC-18790 and quinidine showed no frequency dependence, implying block of resting channels and/or very rapid block of open channels; this is in contrast to dofetilide, which displayed slow onset kinetics of block. Thus, we conclude that, 1) unlike quinidine, OPC-18790 does not significantly inhibit currents obtained by expression of the cardiac potassium channel clones Kv1.4, Kv1.5 and Kv2.1; 2) like quinidine and dofetilide, OPC-18790 blocks I(Kr) in
AT-1
cells, but the kinetics of block onset more closely resemble those of quinidine than dofetilide; and 3) block of I(Kr) appears to be an important mechanism underlying the action potential-prolonging properties of OPC-18790.
...
PMID:Inhibition of cardiac potassium currents by the vesnarinone analog OPC-18790: comparison with quinidine and dofetilide. 906
While the bulk of the existing data are in diabetic renal disease, there are some animal and clinical studies that compare the effects of angiotensin I (
AT-1
) receptor antagonists to angiotensin converting enzyme (ACE) inhibitors in renal disease of nondiabetic origin. Based on these data, preservation of renal function and morphology occurs with
AT-1
receptor antagonists in animal models where renal injury is hemodynamically mediated such as in the remnant kidney. Conversely, in non-hemodynamically mediated renal injury such as in puromycin nephrosis,
AT-1
receptor antagonists have not consistently protected against declines in glomerular filtration rate or development of interstitial fibrosis. This may, however, be related to dosage, since high doses of
AT-1
receptor antagonists show some protection against progression in these models. It is too early, however, to make judgments regarding the clinical impact of the
AT-1
receptor antagonists on progression of nondiabetic renal disease. The result of the ELITE trial support the concept that progression of renal dysfunction associated with
heart failure
is ameliorated to a similar extent between ACE inhibitors and the
AT-1
receptor antagonist, losartan. The
AT-1
receptor antagonist group also had fewer side effects including the absence of cough as well as a lower, albeit not statistically significant, incidence of hyperkalemia. Thus, the emerging database supports the concept that
AT-1
receptor antagonists have an efficacy similar to ACE inhibitors for preserving renal function and morphology in hemodynamically mediated renal injury. It is unclear, however, whether this drug class will reduce immunologically-mediated renal injury.
...
PMID:Angiotensin II receptor blockade and progression of nondiabetic-mediated renal disease. 940 25
Angiotensin II receptor antagonists (
AT-1
) represent a new group of orally active antihypertensive agents. Activation on
AT-1
receptor leads to vasoconstriction, stimulation of the release of catecholamines and antidiuretic hormone with production of thirst, and promote growth of vascular and cardiac muscle; these effects are blocked by
AT-1
antagonist agents. The first chemically useful, orally active
AT-1
receptor antagonist was losartan, followed by other agents currently in clinical use, such as: valsartan, eprosartan, irbesartan, telmisartan, candesartan, and many others under investigation.
AT-1
receptor antagonists are effective in reducing high blood pressure in hypertensive patients. Monotherapy in mild to moderate hypertension controls blood pressure in 40 to 50% of these patients; when a low dose of a thiazide diuretic is added, 60 to 70% of patients are controlled. The efficacy is similar to angiotensin-converting enzyme inhibitors, diuretics, calcium antagonists and beta-blocking agents. Tolerability has been reported to be very good.
AT-1
receptor antagonists would be a drug of choice in otherwise well-controlled hypertensive patients treated with angiotensin-converting enzyme inhibitors who developed cough or angioedema. The final position in the antihypertensive therapy in this special population and other clinical situations, such as left ventricular hypertrophy,
heart failure
, diabetes mellitus and renal disease, has to be determined in large prospective clinical trials, some of which are now being conducted.
...
PMID:Angiotensin II receptor antagonists in arterial hypertension. 1085 84
Authors describe pharmacotherapy used in the end stage of
heart failure
(EF 20.5 +/- 4.1%) in routine cardiologic practice in Slovakia, and compare it with pharmacotherapy after the discharge from specialized centers. Medical records of 107 (11 females) were evaluated. At admission vs. discharge, digoxin was prescribed in 94 vs. 91, ACE inhibitors in 86 vs. 94, loop diuretics in 90 vs. 94,
AT-1
antagonists in 0 vs. 4, beta blockers in 23 vs. 55. The dosage of ACE inhibitors used in routine practice was rather low.
...
PMID:[Pharmacologic therapy of heart failure]. 1172 66
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.
...
PMID:Renin angiotensin system and gender differences in the cardiovascular system. 1186 Oct 38
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.
...
PMID:Angiotensin AT-1 receptor antagonism: complementary or alternative to ACE inhibition in cardiovascular and renal disease? 1243 89
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.
...
PMID:Stimulation of cardiac sympathetic nerve activity by central angiotensinergic mechanisms in conscious sheep. 1475 46
Angiotensin II (AT II) is a final product of the renin-anglotensin-aldosterone system (RAS) and presents one of the most influential factors in the pathogenesis of atherosclerosis, acute coronary syndrome, myocardial dysfunction and
heart failure
. ACE-inhibitors (ACEI), beside beta adrenergic blockers, are a cornerstone of the current chronic
heart failure
(CHF) treatment. Evidence based medicine has not yet proved any significant beneficial effects of ACEI in patients with unstable angina pectoris (UAP), although according to the SoLVD study testing the possible effects of ACEI in patients with significant left ventricular dysfunction and/or CHF, there was a significant hospitalization rate reduction as well as less transformation of UAP to myocardial infarction in patients treated with ACEI. In the GISSI 3, ISIS 4 and CCS studies, ACEI was given within the first 24 hours and continued for 4-6 weeks. According to pooled results, ACE inhibitor could save 11/1000 patients with ST-elevation myocardial infarction (STEMI) and only 1/1000 patients with non ST-elevation myocardial infarction (NSTEMI). In the SAVE, AIRE and TRACE studies, ACEI was started later, i.e. 3-16 days after acute myocardial infarction and continued for several years. ACEI therapy resulted in a significantly lower mortality during the first year, and an even 20% relative reduction in the total mortality during the 4-year follow up. The effects of ACEI were even more prominent in more severe myocardial dysfunction, as it was well known that they could slow or stop unfavorable myocardial remodeling. Conclusively, ACEI should be given as early as possible to all patients with acute myocardial infarction, if no contraindications. The HOPE study showed efficacy of ACEI in the primary prevention of ischemic heart disease in high risk individuals, and the EUROPA study showed a favorable effect of ACEI in the secondary prevention of ischemic heart disease in low risk patients. According to these findings, ACEI should be given permenantly following myocardial infarction. These findings suggest the need of a permanent treatment with ACEI in patients having sustaned myocardial infarction. Angiotensin-1 receptor antagonists (
AT-1
antagonists) are a newer generation of neurohormonal antagonists, which block the effects of AT II produced not only through a classic, ACE-dependent pathway but also via alternative pathways (non ACE-dependent) and selectively bind to
AT-1
receptors for AT II. Therefore, they have some theoretical advances in comparison with ACEI. There are 2 relevant studies elucidating their possible role in treating patients with or post-myocardial infarction. The OPTIMAAL study did not prove losartan to be better than an ACEI (captopril), while the VALIANT study showed that the effects of valsartan vs. captopril were statistically nonsignificantly different. Furthermore, there is no sense to combine
AT-1
antagonist and ACEI, while a combination of
AT-1
antagonist and a beta blocker is justified. In other words,
AT-1
antagonist (the class effect is disputable) should be given to patients with acute myocardial infarction or to post-myocardial infarction patients who cannot take ACEI.
...
PMID:[ACE inhibitors and angiotensin II receptor antagonists in acute coronary syndrome]. 1520 98
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.
...
PMID:Heart failure in patients with chronic kidney disease. 1563 34
Heart failure
(HF) is a multifactorial and progressive disease that has been associated with multiple systemic and vascular alterations. Previous reports from our laboratory showed that in 2-month-old Bio-To2 Syrian cardiomyopathic hamsters (SCH) that have not yet developed the clinical manifestations of HF, the vascular contractility induced by 0.1 microM angiotensin II was approximately 35% greater than in control animals. This finding was observed concomitantly with an increased aortic ACE activity. To further evaluate the mechanisms underlying angiotensin II-enhanced vascular contraction, concentration-response curves for angiotensin II (0.01 nM-10 microM) were constructed before and after the addition of prazosin (alpha-1 blocker), NS-398 (selective COX-2 blocker) and BQ-123 (ET-1A-receptor antagonist) in aortic rings from 2-month-old SCH. The binding capacity and affinity of the
AT-1
receptors were also evaluated in aortic homogenates using 125I-angiotensin II. Age-matched golden hamsters were used as controls (CT). Our results indicate that incubation with either 10 microM prazosin or 10 microM NS-398 did not modify EC50 or Emax values for angiotensin II indicating that norepinephrine and prostaglandins are not involved in the enhanced contractile action of angiotensin II. However, 10 microM BQ-123 reduced by 40% the contraction induced by 1.0 microM angiotensin II (from 1.05+/-0.04 to 0.6475+/-0.06 g/mg tissue, n = 5, P < 0.05), suggesting that in cardiomyopathic hamsters, the action of angiotensin II is mediated in part by ET-1. At lower angiotensin II concentration (0.1 microM), the ET-1-dependent contraction decreases to 29%. In addition, although dissociation constants for labeled angiotensin II were found to be similar in the aorta of SCH and control animals (K(D): CT = 7.8 nM and SCH = 5.1 nM), 125I-angiotensin II binding capacity was about 2-fold greater in SCH than in controls (Bmax: SCH = 1113 and CT = 605 fmol/mg protein). Altogether these results suggest that in 2-month-old SCH the enhanced response of angiotensin II in the vasculature is mediated both by an increased binding capacity for the hormone and facilitation of the ET-1 action.
...
PMID:Increased vascular angiotensin II binding capacity and ET-1 release in young cardiomyopathic hamsters. 1650 5
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