Antihypertensive efficacy and safety of olmesartan medoxomil and ramipril in elderly mild to moderate essential hypertensive patients with or without metabolic syndrome: a pooled post hoc analysis of two comparative trials

BACKGROUND

Two recent identically designed trials (one Italian and one European multinational) have compared the head-to-head efficacy and safety of the angiotensin II receptor blocker olmesartan medoxomil and the angiotensin converting enzyme inhibitor ramipril, in elderly patients with essential hypertension.

OBJECTIVE

The aim of the present study was to assess the antihypertensive efficacy of olmesartan and ramipril in elderly patients with hypertension, with or without metabolic syndrome, by performing a pooled analysis of data from the two head-to-head trials.

METHODS

After a 2-week, placebo wash-out, 1,453 treated or untreated elderly hypertensive patients aged 65-89 years [with sitting office diastolic blood pressure (DBP) 90-109 mmHg and/or sitting office systolic BP (SBP) 140-179 mmHg] were randomized to 12-weeks of double-blind treatment with olmesartan 10 mg or ramipril 2.5 mg once daily. Treatment could be up-titrated to 20 and 40 mg for olmesartan, and 5 and 10 mg for ramipril, after the first 2 and 6 weeks, respectively, in patients with inadequately controlled BP (BP ≥ 140/90 mmHg for non-diabetics and ≥ 130/80 mmHg for diabetics). Office BP was measured at randomization and after 2, 6 and 12 weeks of treatment. 24-h ambulatory BP recordings were obtained at randomization and after 12 weeks.

RESULTS

Of the 1,426 patients in the intent-to-treat analysis, 735 (51.5 %) had metabolic syndrome (olmesartan, n = 372; ramipril, n = 363). After 12 weeks of treatment, baseline-adjusted office BP reductions were greater (p < 0.05) with olmesartan (SBP 17.0 mmHg; 95% CI 18.4, 15.6; DBP 9.6 mmHg; 95% CI 10.4, 8.8) than with ramipril (SBP 14.7 mmHg; 95% CI 16.1, 13.2; DBP 8.4 mmHg; 95% CI 9.2, 7.6) in patients with metabolic syndrome. In these patients, BP normalization rates were also greater with olmesartan than with ramipril (46.0 vs. 35.8%, p < 0.01). Similarly, in patients without metabolic syndrome, the antihypertensive efficacy of olmesartan was also significantly (p < 0.05) better than that of ramipril. In the subgroup of patients with valid ambulatory BP (ABP) recordings and metabolic syndrome (olmesartan, n = 182; ramipril, n = 170), the reduction in mean 24-h ABP was greater with olmesartan (SBP 10.2 mmHg; 95% CI 11.8, 8.6; DBP 6.6 mmHg; 95% CI 7.5, 5.6) than with ramipril (SBP 8.5 mmHg; 95% CI 10.2, 6.9; DBP 4.7 mmHg; 95% CI 5.7, 3.7), with a statistically significant (p < 0.01) difference for the DBP comparison. The proportion of patients experiencing drug-related adverse events was comparable in patients with (olmesartan 2.4 % vs. ramipril 2.8 %) and without (3.5 vs. 3.7 %) metabolic syndrome.

CONCLUSIONS

Olmesartan provides more effective BP control than ramipril in elderly hypertensive patients with and without metabolic syndrome.

Activation of NADPH oxidase 4 in the endoplasmic reticulum promotes cardiomyocyte autophagy and survival during energy stress through the protein kinase RNA-activated-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/activating transcription factor 4 pathway

RATIONALE

Autophagy is an essential survival mechanism during energy stress in the heart. Oxidative stress is activated by energy stress, but its role in mediating autophagy is poorly understood. NADPH oxidase (Nox) 4 is an enzyme that generates reactive oxygen species (ROS) at intracellular membranes. Whether Nox4 acts as a sensor of energy stress to mediate activation of autophagy is unknown.

OBJECTIVE

We investigated whether Nox4 is involved in the regulation of autophagy and cell survival during energy stress in cardiomyocytes.

METHODS AND RESULTS

Production of ROS in cardiomyocytes was increased during glucose deprivation (GD) in a Nox4-dependent manner. Protein levels and the ROS-producing activity of Nox4 were increased in the endoplasmic reticulum (ER), but not in mitochondria, in response to GD. Selective knockdown of Nox4, but not Nox2, or selective reduction of ROS in the ER with ER-targeted catalase, but not mitochondria-targeted perioxiredoxin 3, abrogated GD-induced autophagy. Nox4 promoted autophagy during GD through activation of the protein kinase RNA-activated-like ER kinase pathway by suppression of prolyl hydroxylase 4. The decrease in cell survival during GD in the presence of Nox4 knockdown was rescued by reactivation of autophagy by Atg7 overexpression, indicating that the effect of Nox4 on cell survival is critically mediated through regulation of autophagy. Nox4 was activated during fasting and prolonged ischemia in the mouse heart, where Nox4 is also required for autophagy activation and cardioprotection.

CONCLUSIONS

Nox4 critically mediates autophagy in response to energy stress in cardiomyocytes by eliciting ROS in the ER and stimulating the protein kinase RNA-activated-like ER kinase signaling pathway.

Atrial natriuretic Peptide single nucleotide polymorphisms in patients with nonfamilial structural atrial fibrillation

Background

Atrial natriuretic peptide (ANP) has antihypertrophic and antifibrotic properties that are relevant to AF substrates. The –G664C and rs5065 ANP single nucleotide polymorphisms (SNP) have been described in association with clinical phenotypes, including hypertension and left ventricular hypertrophy. A recent study assessed the association of early AF and rs5065 SNPs in low-risk subjects. In a Caucasian population with moderate-to-high cardiovascular risk profile and structural AF, we conducted a case-control study to assess whether the ANP –G664C and rs5065 SNP associate with nonfamilial structural AF.

Methods

168 patients with nonfamilial structural AF and 168 age- and sex-matched controls were recruited. The rs5065 and –G664C ANP SNPs were genotyped.

Results

The study population had a moderate-to-high cardiovascular risk profile with 86% having hypertension, 23% diabetes, 26% previous myocardial infarction, and 23% left ventricular systolic dysfunction. Patients with AF had greater left atrial diameter (44 ± 7 vs. 39 ± 5 mm; P < 0.001) and higher plasma NTproANP levels (6240 ± 5317 vs. 3649 ± 2946 pmol/mL; P < 0.01). Odds ratios (ORs) for rs5065 and –G664C gene variants were 1.1 (95% confidence interval [CI], 0.7–1.8; P = 0.71) and 1.2 (95% CI, 0.3–3.2; P = 0.79), respectively, indicating no association with AF. There were no differences in baseline clinical characteristics among carriers and noncarriers of the –664C and rs5065 minor allele variants.

Conclusions

We report lack of association between the rs5065 and –G664C ANP gene SNPs and AF in a Caucasian population of patients with structural AF. Further studies will clarify whether these or other ANP gene variants affect the risk of different subphenotypes of AF driven by distinct pathophysiological mechanisms.

Abstract 45: Reduced Vascular Remodeling and Improved Endothelial Function in Transglutaminase 2 Knock-Out Mice Treated with Angiotensin II

Transglutaminase 2 (TG2) may modulate cell-matrix interactions by inducing cross-linking of proteins. We previously demonstrated that angiotensin II (Ang II) positively regulated TG2 expression in vascular smooth muscle cells from SHR. Here we hypothesized that Ang II induces vascular remodeling in part through TG2.

TG2-knockout mice (TG2-K/O, 8 weeks old, 6 for each group) and age-matched wild type (WT) control mice were treated or not with Ang II (400 ng/kg/min) for 14 days. Blood pressure (BP) was measured by tail-cuff method. Endothelium-dependent and -independent relaxation were assessed by concentration-response curves to acetylcholine (1 nM to 100 μM) ± L-NAME (100 μM) and sodium nitroprusside (10 nM to 1 mM) respectively, in mesenteric arteries pre-contracted with norepinephrine (10 μM). Media-to-lumen ratio (M/L) and cross sectional area (CSA) were evaluated on pressurized preparations.

BP was higher in TG2-K/O mice compared to WT (120.3±1.3 mmHg vs 88.3±1.9 mmHg, P<0.05), Ang II infusion significantly increased BP only in WT (+28% vs untreated WT, P<0.05), whereas BP was unchanged in TG2-K/O after Ang II infusion. Endothelium-dependent relaxation was similarly preserved in untreated WT, TG2-K/O and Ang II-treated TG2-K/O. Ang II infusion impaired acetylcholine-induced relaxation only in WT (-50% vs untreated WT, P<0.05). L-NAME blunted acetylcholine-induced relaxation in all the groups except in Ang II-treated WT, suggesting an impairment of NO production only in this group. Endothelium-independent relaxation was similar in all groups. TG2-K/O presented reduced M/L as compared to WT (4.8±0.3% vs 6.5±0.2%, P<0.05). Ang II infusion increased M/L only in WT (+13% vs untreated WT, P<0.05). M/L resulted unchanged in TG2-K/O after Ang II infusion. CSA was similar in all groups.

In conclusion, despite the higher BP values, TG2-K/O presented improved vascular remodeling compared to WT. Ang II failed to increase M/L and impair endothelial function in TG2-K/O. Hence TG2 may play a role in Ang II-induced vascular structural and functional alterations.

Abstract 406: Improved Angiotensin II Type 2 Receptor Expression and Function in Transglutaminase 2 Knock-Out Mice Treated with Angiotensin II

Objective: Transglutaminase 2 (TG2) induces transamidation and cross-linking of proteins that can modulate receptor interaction. Angiotensin II (AngII) may regulate TG2 and AngII type 2 receptor (AT2) expression and function. We hypothesized that AngII may impair AT2 expression and function through TG2.

Methods: TG2-knockout mice (TG2-K/O, 8 weeks old, 6 for each group) and age-matched wild type (WT) mice were treated or not with AngII (400 ng/kg/min) for 14 days. Vascular reactivity was assessed in response to sodium nitroprusside (SNP, 10 nM to 1 mM), in mesenteric arteries pre-contracted with norepinephrine (10 μM). AT2 function was assessed by concentration-response curve to the selective AT2 agonist Compound 21 (C21, 1nM to 1 μM) in mesenteric arteries pre-contracted with norepinephrine. AT2 expression in aorta was evaluated by immunoblotting.

Results: C21-induced relaxation was similar in untreated WT, and in untreated TG2-K/O. C21-induced relaxation was improved only in AngII-treated TG2-K/O (2-fold increase vs untreated TG2-K/O, P<0.001). SNP dependent relaxation was similar in all groups. AT2 receptor expression was similar in untreated WT and untreated TG2-K/O. AT2 was reduced by AngII in WT (-36±6% vs untreated WT, P<0.01), and significantly increased in TG2-K/O (+53±4% vs untreated TG2-K/O, P<0.001).

Conclusions: AngII fails to reduce AT2 expression and function in TG2-K/O mice. Therefore, AngII may negatively modulate AT2 receptor expression and function through TG2.

Global cardiovascular risk management in primary prevention

Although the impressive progression of modern diagnostic opportunities and therapeutic options, cardiovascular diseases still represent the leading causes of morbidity and mortality, worldwide. Beyond the effective pharmacological treatment of major cardiovascular disease or sequelae, however, cardiovascular diseases developing in adult individuals are largely preventable. The substantial failure to prevent cardiovascular disease in the 20th century generation is mostly linked to the ineffective use, as well as to the underuse of available preventive strategies. As a consequence, preventive strategies should be encouraged at both individual and population level, to substantially improve healthy status of the general population and reduce the burden of cardiovascular diseases in Western and Developing Countries.

Growth factors in preeclampsia: a vascular disease model. A failed vasodilation and angiogenic challenge from pregnancy onwards?

Preeclampsia is the major cause of maternofetal and neonatal morbi-mortality including intrauterine growth retardation, miscarriages and stillbirths. Inadequate vascular dilation and angiogenesis represent the crucial underlying defect of gravidic hypertension, denoting a failed response to the vasodilatory and pro-angiogenic challenge imposed by pregnancy, especially if multifetal. A similar pathogenesis appears involved in gestational diabetes. In this review we aimed to provide a hint on understanding the deeply involved angiogenic disorders which eventually culminate in utero-placental failure. The key players in these complex processes may be found in an intricate network of growth factors (GFs) and GF inhibitors, controlled by several vascular risk factors modulated by environment and genes, which eventually impact on early and late cardiovascular outcomes of mother and fetus.