Losartan reduces the burden and cost of ESRD: public health implications from the RENAAL study for the European Union.
(9/1828)
Type 2 diabetes is the leading cause of end-stage renal disease (ESRD) in most industrialized countries in Europe. The RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) Study evaluated the renal protective effects of losartan versus placebo on a background of non-ACE-I/non-AIIA conventional antihypertensive therapy in 1513 patients with type 2 diabetes and nephropathy. Losartan reduced the incidence of doubling of serum creatinine, end-stage renal disease (ESRD), or death by 16% (P=0.022) and reduced the risk of progression to ESRD, defined as the initiation of dialysis or transplantation, by 29% (P=0.002). We set out to estimate the potential effect of losartan on the burden and costs associated with ESRD over 3.5 years in the European Union (EU). The risk reduction in new cases of ESRD was calculated by combining type 2 diabetes population estimates for the EU with the percent absolute risk reduction of ESRD in patients treated with losartan as observed in RENAAL. The number of days each patient experienced ESRD was defined as the length of time from onset of ESRD until the minimum of death or 3.5 years. ESRD-free person-years avoided with losartan treatment were calculated by combining the population estimate with the ESRD days avoided divided by number of days in a year. ESRD costs from Germany were used to approximate the potential cost savings from reduced time with ESRD and fewer ESRD cases on a EU wide basis. There are approximately 700,000 diagnosed type 2 diabetes patients with proteinuria (urine albumin/creatinine >or=300 mg/g) in the EU. The addition of losartan to the treatment regimen of these patients is expected to lead to a reduction of 44,100 cases of ESRD, 64,400 fewer person-years with ESRD, and reduce ESRD-related costs by euro 2.6 billion over 3.5 years based on RENAAL data. Treatment with losartan not only reduced the incidence of ESRD, but also can result in substantial cost savings in the European Union. (+info)
CS-886, a new angiotensin II type 1 receptor antagonist, ameliorates glomerular anionic site loss and prevents progression of diabetic nephropathy in Otsuka Long-Evans Tokushima fatty rats.
(10/1828)
BACKGROUND: Diabetic nephropathy is a leading cause of end-stage renal disease in industrialized countries. Previous studies have documented that angiotensin converting enzyme (ACE) inhibitors consistently reduce albuminuria and retard the progression of diabetic nephropathy. However, the involvement of angiotensin II in diabetic nephropathy is not fully understood. MATERIALS AND METHODS: In this study we compared the effects of CS-866, a new angiotensin II type 1 receptor antagonist, to that of an ACE inhibitor, temocapril hydrochloride, on the development and progression of diabetic nephropathy using Otsuka Long-Evans Tokushima fatty rats, a type II diabetes mellitus model animal. RESULTS: High doses of CS-866 or temocapril treatment were found to significantly improve urinary protein and beta(2)-microglobulin excretions in diabetic rats. In electron microscopic analysis, loss of glomerular anionic sites, one of the causes of glomerular hyperpermeability in diabetic nephropathy, was found to be significantly prevented by CS-866 treatment. Light microscopic examinations revealed that both treatments ameliorated glomerular sclerosis and tubulointerstitial injury in diabetic rats. Furthermore, high doses of CS-866 or temocapril treatment significantly reduced the positive stainings for transforming growth factor-beta (TGF-beta), vascular endothelial growth factor, and type IV collagen in glomeruli of diabetic rats. CONCLUSIONS: These results indicate that intrarenal angiotensin II type 1 receptor activation plays a dominant role in the development and progression of diabetic nephropathy. Our study suggests that CS-866 represents a valuable new drug for the treatment of diabetic patients with nephropathy. (+info)
Angiotensin II-induced modulation of endothelium-dependent relaxation in rabbit mesenteric resistance arteries.
(11/1828)
The role of local endogenous angiotensin II (Ang II) in endothelial function in resistance arteries was investigated using rabbit mesenteric resistance arteries. First, the presence of immunoreactive Ang II together with Ang II type-1 receptor (AT1R) and angiotensin converting enzyme (ACE) was confirmed in these arteries. In endothelium-intact strips, the AT1R-blocker olmesartan (1 microM) and the ACE-inhibitor temocaprilat (1 microM) each enhanced the ACh (0.03 microM)-induced relaxation during the contraction induced by noradrenaline (NA, 10 microM). Similar effects were obtained using CV-11974 (another AT1R blocker) and enalaprilat (another ACE inhibitor). The nitric-oxide-synthase inhibitor NG-nitro-L-arginine (L-NNA) abolished the above effect of olmesartan. In endothelium-denuded strips, olmesartan enhanced the relaxation induced by the NO donor NOC-7 (10 nM). Olmesartan had no effect on cGMP production (1) in endothelium-intact strips (in the absence or presence of ACh) or (2) in endothelium-denuded strips (in the absence or presence of NOC-7). In beta-escin-skinned strips, 8-bromoguanosine 3',5' cyclic monophosphate (8-Br-cGMP, 0.01-1 microM) concentration dependently inhibited the contractions induced (a) by 0.3 microM Ca2+ in the presence of NA+GTP and (b) by 0.2 microM Ca2++GTPgammaS. Olmesartan significantly enhanced, while Ang II (0.1 nM) significantly inhibited, the 8-Br-cGMP-induced relaxation. We propose the novel hypothesis that in these arteries, Ang II localized within smooth muscle cells activates AT1Rs and inhibits ACh-induced, endothelium-dependent relaxation at least partly by inhibiting the action of cGMP on these cells. (+info)
Screening and identification of the up-regulated genes in human mesangial cells exposed to angiotensin II.
(12/1828)
Accumulation of extracellular matrix (ECM) in the glomerular mesangium is a common feature of many progressive renal diseases. Angiotensin II (Ang II) plays a major role in the progression of chronic kidney diseases in part by induction of ECM. However, the precise molecular signals responsible for this effect are unknown. To explore possible molecular mechanisms of ECM production related to Ang II, we screened and identified genes up-regulated by Ang II in cultured human mesangial cells (MC). Detection of up-regulated genes was determined by mRNA populations from human MC with and without Ang II stimulation (10(-6) mol/l, 24 h) by suppression subtractive hybridization. Reverse Northern blot analysis was performed to screen for differentially expressed genes. Full-length cDNAs of three novel genes were isolated by rapid amplification of cDNA ends (RACE)-polymerase chain reaction (PCR). One of these novel genes, AngRem104, was further investigated by Northern blot, Western blot and reverse transcription (RT)-PCR. The bioinformatics analysis implied that AngRem104 coded for a nuclear protein that was widely expressed in various normal human tissues. Moreover, up-regulation of AngRem104 induced by Ang II was time-dependent and was dose-dependently blocked by the Ang II type 1 receptor antagonist, Losartan. Interestingly, we also demonstrated that AngReam104 was associated with increased fibronectin expression. We conclude that AngRem104 is a novel human gene that is related to the expression of fibronectin and that is up-regulated by Ang II in human MC. These findings may lead to new insights into the mechanisms of glomerular sclerosis associated with Ang II. (+info)
Chronic angiotensin II inhibition increases levels of calcitonin gene-related peptide mRNA of the dorsal root ganglia in spontaneously hypertensive rats.
(13/1828)
We previously reported that the vasodilation mediated by calcitonin gene-related peptide (CGRP)-containing nerves and level of CGRP mRNA in the dorsal root ganglia (DRG) in spontaneously hypertensive rats (SHR) decreased with age, and that the reduced function of CGRP nerves was restored by chronic inhibition of angiotensin II. The present study was performed to investigate the effect of long-term treatment with angiotensin II type-1 receptor antagonists (L-158,809 and olmesartan), an angiotensin converting enzyme inhibitor (temocapril) and hydralazine on levels of CGRP mRNA in DRG of SHR and the contents of CGRP in the mesenteric artery and atrium. The level of CGRP mRNA and degree of CGRP-like immunoreactivities (CGRP-LI) were measured by Northern blot hybridization assay and enzyme-linked immunosorbent assay, respectively. Seven week-treatment of 8 week-old SHR with temocapril (0.005%), L-158,809 (0.001%), olmesartan (0.01%) or hydralazine (0.01%) administered in drinking water significantly lowered the systolic blood pressure of SHR. The level of CGRP mRNA in the DRG of control SHR was significantly lower than that in normotensive Wistar Kyoto rats (WKY), whereas the level of CGRP-LI in the mesenteric artery and atrium of SHR were significantly greater than those in WKY. Treatment of SHR with temocapril, L-158,809, or olmesartan, but not hydralazine, significantly elevated the levels of CGRP mRNA in DRG, markedly increased the level of CGRP-LI in the mesenteric artery, and slightly increased the CGRP-LI level in the atrium. These results suggest that long-term inhibition of angiotensin II restores the reduced expression of CGRP mRNA in DRG and may facilitate neurotransmission of CGRP-containing vasodilator nerves in SHR. (+info)
Role of bradykinin in renoprotective effects by angiotensin II type 1 receptor antagonist in salt-sensitive hypertension.
(14/1828)
To elucidate whether bradykinin is involved in the renoprotective effect produced by angiotensin II type 1 receptor antagonist (AT1A) in chronic salt-sensitive hypertension, Dahl salt-sensitive rats receiving a high-salt (8%) diet were treated either with an AT1A (candesartan, 1 mg/kg/day), a bradykinin B2 receptor antagonist (BKB2A; FR172357, 30 mg/kg/day) or a combination of AT1A and BKB2A for 7 weeks. None of the treatments changed the markedly increased systolic blood pressure induced by a high-salt diet. However, chronic treatment with AT1A significantly improved the histological hallmarks of renal damage-i.e., glomerular sclerosis and cell proliferation-despite the presence of severe hypertension. This beneficial action of AT1A was abolished by the concomitant administration of BKB2A. In agreement with these histologically based findings, increases in levels of creatinine clearance induced by AT1A were also reversed back to the basal levels when BKB2A was administered in conjunction with AT1A. Furthermore, urinary excretions of nitrate plus nitrite and prostaglandin E2 increased moderately in response to the administration of AT1A alone, but not in combination with BKB2A. Thus, the blockade of bradykinin signaling abrogates the renoprotective actions of the angiotensin II type 1 (AT1) receptor antagonism. Collectively, these data show that when AT1 action is chronically blocked, endogenous bradykinin plays a pivotal role in preventing the progression of glomerular injury in salt-sensitive hypertension. (+info)
Effects of valsartan with or without benazepril on blood pressure, angiotensin II, and endoxin in patients with essential hypertension.
(15/1828)
AIM: To evaluate the effects of valsartan (Val) with or without benazepril (Ben) on blood pressure and plasma levels of angiotensin (Ang II) and digoxin-immunoreactive factors (endoxin) in patients with essential hypertension. METHODS: Ninety patients with essential hypertension were randomly divided into 3 groups (n=30 per group): Ben group (Ben 10 mg/d, po); Val group (Val 80 mg/d, po); combination drug therapy group (Val 80 mg/d+Ben 10 mg/d, po); all patients were treated for 12 weeks. Age and sex-matched 20 normal subjects were served as control group. RESULTS: The levels of plasma endoxin and Ang II in patients with essential hypertension were remarkably higher than those in normal subjects. The levels of plasma Ang II and endoxin were all obvious positive correlation with systolic blood pressure (SBP) and diastolic blood pressure (DBP) (Ang II: r=0.5151, 0.7978; endoxin: r=0.4706, 0.7274, respectively). Within 6 weeks of drug intervene, SBP and DBP were remarkably decreased in 3 groups. After 6 weeks, SBP and DBP were continuously decreased in Ben group and Val+Ben group, but not in Val group. Level of plasma Ang II was remarkably decreased as SBP and DBP decreased in Ben group and Val+Ben group; level of plasma Ang II was remarkably increased in Val group. CONCLUSION: Val with or without Ben remarkably decreased SBP and DBP in patients with essential hypertension within 6 weeks. Antihypertensive efficacy was weakened after long-term use of Val alone. The antihypertensive effect of Val+Ben group was the most remarkable among 3 groups and could avoid the side effects of high plasma Ang II. (+info)
Angiotensin AT1 receptor antagonist losartan and the defence reaction in the anaesthetised rat. Effect on the carotid chemoreflex.
(16/1828)
Modulation at the level of the nucleus tractus solitarii (NTS) appears to be an effective way of controlling cardiovascular reflexes. Angiotensin II acting on angiotensin AT1 receptors at the central nervous system appears to have an important role in these modulatory processes. The hypothalamic defence area (HDA) is a potential source of descending fibres containing angiotensin II that innervate the NTS. We investigated the effect of AT1 receptor blockade in the NTS on the response to stimulation of HDA in anaesthetised rats treated with the neuromuscular blocking agent pancuronium bromide. The characteristic increase in heart rate, blood pressure and phrenic nerve activity evoked by electrical stimulation of HDA is decreased by the microinjection of the AT1 receptor antagonist losartan into the NTS and the cardiovascular response to carotid body chemical stimulation is also reduced. These results support the hypothesis that AT1 receptors in the NTS play a role in the modulation of cardiovascular reflexes, and modify the influence exerted on the processing of these reflexes by other areas of the central nervous system. (+info)