Cardiovascular (CV) events are a major cause of morbidity and mortality in haemodialysis (HD) patients. Hypertension, increased arterial stiffness and left ventricular (LV) hypertrophy are highly prevalent and are often poorly controlled. Volume overload is an important factor and survival could be improved by treatment strategies that preserve residual renal function (RRF), reduce blood pressure, and decrease arterial stiffness and LV hypertrophy. Angiotensin II receptor blocker (ARB) treatment can prevent CV events in patients with hypertension and heart failure. However, few data exist in patients with chronic renal failure and it is not known whether ARB treatment improves clinical outcome in HD patients.This is a randomized, controlled and double-blinded intervention study. A total of 82 HD patients from six Danish HD centres will be treated for a year with an ARB (irbesartan) or placebo. The inclusion criteria are urine output > 300 ml/day, dialysis vintage < 1 year and LV ejection fraction > 30%. The primary outcomes are change in RRF, LV hypertrophy, arterial stiffness and intra-dialytic haemodynamics.If ARB-treatment improves RRF and intermediate CV endpoints in a group of newly started HD patients, it may improve the survival for this high risk population.The trial is investigator-initiated, investigator-driven and supported by the Danish Agency for Science, Technology and Innovation and several private foundations.Clinical Trials ID: NCT00791830.

Circulating microparticles (MPs) and endothelial progenitor cells (EPCs) correlate with endothelial dysfunction and contribute to the pathogenesis of atherosclerosis. In this context, we explored whether the angiotensin II type I receptor antagonist, irbesartan, exerts a pharmacological control in the atherosclerotic process by the improvement of EPC mobilization and inhibitory effects on MP release and VEGF and SDF-1α levels in the hypertensive-hypercholesterolemic (HH) hamster model. The HH hamsters were treated with irbesartan (50mg/kg b.w/day administered by gavage) for 4 month (HHI). We analyzed MP/EPC infiltration in vascular wall before and after irbesartan administration as well as the endothelial function and expression of VEGF/SDF-1α in plasma and tissue and of molecular pathways activated by them. The results showed that treatment with irbesartan significantly increased EPC infiltration and decreased MP infiltration. The mechanisms underlying this response include the reduction/increase of a number of specific membrane receptors exposed by MPs (TF, P-Selectin, E-Selectin, PSGL-1, Rantes), respectively, by EPCs (β2-Integrins, α4β1-integrin), the augmentation of endothelium-mediated vasodilation and the reduction of protein expression of VEGF/SDF-1α followed by: (1) the diminishment of pro-inflammatory endothelial cytokines: VEGFR1, VEGFR2, CXCR4, Tie2, PIGF with role in EPC homing to sites of damaged endothelium; and (2) the increase of protein expression of COX-2, PGI2 synthase molecules with role in the improvement of arterial wall vasodilatation. In conclusion, the study underlines that irbesartan administration therapeutically improves/reduces EPC, respectively, MP mobilization and this action may be of salutary relevance contributing to its beneficial cardiovascular effects.

KCNH2 (hERG) potassium channels have an integral role in regulating the excitability of smooth muscle cells. Some pathways driven by angiotensin II, nitric oxide and adrenergic receptors blocker are involved in modulating the properties of KCNH2 potassium channels. And these pathways are closely related to blood pressure regulation. Therefore, we hypothesized that KCNH2 genetic polymorphisms may affect blood pressure response to the antihypertensive drug therapies.To evaluate the interactions between KCNH2 genetic polymorphisms and individual blood pressure response to antihypertensive drugs, 370 subjects with essential hypertension (EH) were studied. In evaluating the interactions between KCNH2 genetic polymorphisms and drug response to blood pressure, multivariable ANOVA analysis followed by Bonferroni correction were carried out.There were statistically significant interactions between KCNH2 (1956, C>T) polymorphism and DBP change (P = 0.010), MAP change (P = 0.014) on azelnidipine or nitrendipine therapy patients at the end of 6 weeks. We found that the KCNH2 (1956,C>T) polymorphism was associated with the hypotensive effects of α,β-ADR blockers of DBP change at the end of 4 and 6 weeks' treatment in an age- and gender-dependent manner (P = 0.007 and 0.019, respectively). Similar results were also observed for changes in MAP at the end of 4 and 6 weeks (P-values were 0.035 and 0.078, respectively). While patients who received imidapril, candesartan and irbesartan therapy, no significant difference in drug response among KCNH2(1956,C>T) genotype was observed.We have reported for the first time that KCNH2 (1956, C>T) polymorphism is associated with efficacy of antihypertensive drugs CCBs and ADR blockers, and may serve as a novel biomarker for individualized therapy for certain antihypertensive drugs.

"Aldosterone breakthrough" observed in patients receiving long-term treatment with angiotensin blockade is strongly associated with increased risk of left ventricular hypertrophy, poor exercise capacity, refractory proteinuria, and declining glomerular filtration rate through the profibrotic actions of aldosterone. To overcome aldosterone breakthrough, we examined the additional organ-protective actions of irbesartan, because irbesartan is an angiotensin II type 1 receptor (AT1R) blocker (ARB) with peroxisome proliferator-activated receptor (PPAR)γ agonistic effects, which mediate organ-protective effects independent of AT1R blockade. In this study, we examined the organ-protective effects of irbesartan in a salt-sensitive hypertension model using AT1aR knockout mice.Aldosterone and 1% NaCl treatment resulted in a significant increase in severe cardiac and renal fibrosis. Irbesartan, but not losartan, significantly reduced renal fibrosis, glomerular injury through inhibition of macrophage infiltration, epithelial-mesenchymal transition, and oxidative stress. Similarly, cardiac fibrosis and myocyte hypertrophy were decreased by irbesartan, but not losartan, treatment, associated with a significant reduction in oxidative stress. Importantly, anti-hepatocyte growth factor (HGF) neutralizing antibody and a PPARγ antagonist (GW9662) attenuated these organ-protective effects of irbesartan. HGF protein level was increased by irbesartan, especially in the kidney and heart, while GW9662 treatment inhibited the increase in HGF level.In this study, we showed that irbesartan, which has not only AT1aR-blocking effects, but also PPARγ agonistic effects accompanied by HGF expression, inhibited organ damage by aldosterone and salt treatment. Second-generation ARBs such as irbesartan, which has the dual actions of AT1R blockade and PPARγ activation, may have clinical value for the treatment of hypertensive patients with aldosterone breakthrough.

BACKGROUND AND OBJECTIVES:

In a multi-center, single-arm, prospective study, we investigated the efficacy and safety of the fixed irbesartan/hydrochlorothiazide combination in Chinese patients with moderate to severe hypertension.

METHODS:

Eligible patients were aged 18-75 years, with a blood pressure of 160-199 mmHg systolic or 100-119 mmHg diastolic during a 1-week wash-out phase off antihypertensive medication. The enrolled patients started antihypertensive treatment with irbesartan/hydrochlorothiazide 150 mg/12.5 mg once daily, with the possible addition of irbesartan 150 mg once daily and up-titration to irbesartan/hydrochlorothiazide 300 mg/25 mg once daily at 4 and 8 weeks of follow-up, respectively. The primary efficacy variable was the goal blood pressure-attaining rate at 12 weeks of follow-up (<140/90 mmHg, or <130/80 mmHg in patients with diabetes mellitus).

RESULTS:

In the intention-to-treat analysis (n = 501) at 12 weeks of follow-up, the goal blood pressure-attaining rate was 57.3 %, and the mean change in blood pressure from baseline was 27.8 mmHg [95 % confidence interval (CI) 26.4-29.1 mmHg; p < 0.001] systolic and 13.5 mmHg (95 % CI 12.6-14.4 mmHg; p < 0.001) diastolic. Similar findings were observed in the per-protocol analysis (n = 449). The prevalence of microalbuminuria and left ventricular hypertrophy significantly (p ≤ 0.01) decreased from 33.4 % (150/449) and 50.4 % (215/427) at baseline to 23.4 % (105/447) and 41.3 % (176/427) at the end of follow-up, respectively. Four patients (2.0 %) reported a serious adverse event.

CONCLUSION:

The fixed irbesartan/hydrochlorothiazide combination may control blood pressure to the target level in about 60 % of Chinese patients with moderate to severe hypertension, with an acceptable safety profile.

This research investigated the impact of angiotensin AT1 receptor (Agtr1) blockade on left ventricular (LV) hypertrophy in a mouse model of human hypertrophic cardiomyopathy (HCM), which carries one functional allele of Mybpc3 gene coding cardiac myosin-binding protein C (cMyBP-C). Five-month-old heterozygous cMyBP-C knockout (Het-KO) and wild-type mice were treated with irbesartan (50 mg/kg/day) or vehicle for 8 weeks. Arterial blood pressure was measured by tail cuff plethysmography. LV dimension and function were accessed by echocardiography. Myocardial gene expression was evaluated using RT-qPCR. Compared with wild-type littermates, Het-KO mice had greater LV/body weight ratio (4.0 ± 0.1 vs. 3.3 ± 0.1 mg/g, P < 0.001), thicker interventricular septal wall (0.70 ± 0.02 vs. 0.65 ± 0.01 mm, P < 0.02), lower Mybpc3 mRNA level (-43%, P < 0.02), higher four-and-a-half LIM domains 1 (Fhl1, +110%, P < 0.01), and angiotensin-converting enzyme 1 (Ace1, +67%, P < 0.05), but unchanged Agtr1 mRNA levels in the septum. Treatment with irbesartan had no effect in wild-type mice but abolished septum-predominant LV hypertrophy and Fhl1 upregulation without changes in Ace1 but with an increased Agtr1 (+42%) in Het-KO mice. Thus, septum-predominant LV hypertrophy in Het-KO mice is combined with higher Fhl1 expression, which can be abolished by AT1 receptor blockade, indicating a role of the renin-angiotensin system and Fhl1 in cMyBP-C-related HCM.

To review the role of angiotensin receptor blockers (ARBs) for the prevention of cardiovascular events in patients with essential hypertension without other compelling indications.Peer-reviewed clinical trials, review articles, and relevant treatment guidelines were identified from MEDLINE and Current Content database (both 1966-November 15, 2012) using the search terms angiotensin receptor blockers (ARBs), azilsartan, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, valsartan, hypertension, myocardial infarction, stroke, heart failure, and cardiovascular outcomes. Results were limited to human trials published in English. Citations from articles were also reviewed for additional references.The focus was on clinical trials evaluating cardiovascular end points of ARBs used in patients with essential hypertension without compelling indications.Data supporting the use of ARBs for reducing cardiovascular events in patients with essential hypertension without compelling indications are inconsistent. To date, only candesartan and losartan have shown a significant reduction in cardiovascular morbidity within this sizable subgroup of patients. In the Study on Cognition and Prognosis in the Elderly (SCOPE) trial, candesartan showed a 27.8% reduction in nonfatal stroke versus placebo (95% CI 1.3-47.2; p = 0.04). Moreover, losartan demonstrated a decrease in all cardiovascular events compared to atenolol in the Cardiovascular Morbidity and Mortality in the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study (RR 0.87; 95% CI 0.77-0.98; p = 0.021).Data supporting the use of ARBs for reducing cardiovascular events in patients with essential hypertension without compelling indications are limited and inconclusive. More studies are needed before ARBs can be routinely recommended as first-line therapy for hypertension management in patients without other compelling indications.

We compared the efficacies of irbesartan and olmesartan after successful stent implantation in patients with stable angina.Twenty-six patients were randomly divided into irbesartan and olmesartan groups and treated for approximately eight months (at follow-up coronary angiography).There were no differences in blood pressure (BP) reduction or late loss between the groups. The BP levels in both groups at follow-up were significantly reduced. The equality of variance of systolic (S)BP (i.e., the intragroup standard deviation of SBP) in the irbesartan group was significantly smaller than that observed in the olmesartan group at follow-up. In addition, log[pentraxin-3] was significantly decreased in all of the patients at follow-up, with no differences between the groups. Interestingly, the levels of log[high-sensitive C-reactive protein (hs-CRP)] measured at 0 weeks were positively associated with in-stent late loss, and among independent biochemical variables in addition to age, gender, body mass index and the kind of angiotensin receptor blockers at 0 weeks, only these levels were related to in-stent late loss, as assessed by a multivariate analysis.The ability of irbesartan to reduce BP is comparable to that of olmesartan, and irbesartan exhibits a lower variance of systolic BP after treatment. The level of log[hs-CRP] before stent implantation is a predictor of in-stent late loss.

This study aims to assess the efficacy and safety of Rehmannia glutinosa acteosides used in combination with the angiotensin receptor blocker irbesartan to treat primary chronic glomerulonephritis. A total of 479 patients diagnosed with primary chronic glomerulonephritis were recruited from outpatient clinics and were randomly assigned to the treatment group (Rehmannia glutinosa acteosides, two 200-mg capsules, bid; and irbesartan, one 150-mg tablet, qd) or the control group (irbesartan, one 150-mg tablet, qd). The primary outcome was 24-h urinary protein. Secondary outcome measures included blood pressure, estimated glomerular filtration rate, erythrocyturia, serum alanine aminotransferase, aspartate transaminase and electrolytes. After 8 weeks of treatment, the treatment group showed a mean reduction in 24-h proteinuria of 36.42% compared to baseline, which was significantly higher than the mean reduction from baseline of 27.97% in the control group (P = 0.0278).Adverse drug reactions occurred at a similarly low rate in the treatment group (0.4%) and control group (1.2%, P = 0.3724). In the treatment of chronic glomerulonephritis, the combination of Rehmannia glutinosa acteosides and irbesartan can reduce proteinuria more effectively than irbesartan alone. Copyright © 2013 John Wiley & Sons, Ltd.

Combination therapy is often required in patients with hypertension, and fixed-dose single-pill combinations have been shown to provide an easier regimen for patients, improving adherence. Irbesartan/amlodipine (Aprovasc(®)) is an angiotensin-receptor blocker/calcium-channel blocker fixed-dose single-pill combination, whose constituent drugs exert additive effects when coadministered. In two randomized, open-label, multicentre, phase III trials, fixed-dose combination therapy with irbesartan/amlodipine was more effective than continuation of irbesartan or amlodipine monotherapy in patients with hypertension not adequately controlled with initial irbesartan or amlodipine monotherapy; there was a significantly greater decrease from baseline in mean seated home systolic blood pressure (primary endpoint) with the fixed-dose combination. The fixed-dose combination was also associated with a greater decrease in mean seated home diastolic blood pressure and mean seated office systolic and diastolic blood pressure than monotherapy. The fixed-dose combination of irbesartan/amlodipine was well tolerated in these patients; most treatment-emergent adverse events were of mild or moderate severity. The most frequent adverse event was peripheral oedema, generally associated with amlodipine treatment.