The protective effects of angiotensin II blockade with olmesartan medoxomil on resistance vessel remodeling (The VIOS study): rationale and baseline characteristics

Tracing angiotensin II's yin-yang effects on cardiovascular-renal pathophysiology

Adverse changes in cardiovascular and renal systems are major contributors to overall morbidity and mortality. Human cardiovascular and renal systems exhibit a complex network of positive and negative feedback that is reflected in the control of vascular tone via angiotensin II (Ang II) based signaling. This review will examine in some depth, the multiple components and processes that control the status and reflect the health of these various cardiovascular and renal systems, such as pathways associated to monomeric G proteins, RhoA/Rho kinase system and ERK, oxidative stress and NO balance. It will specifically emphasize the "yin-yang" nature of Ang II signaling by comparing and contrasting the effects and activity of various systems, pathways and components found in hypertension to those found in Gitelman's and Bartter's syndromes (GS/BS), two rare autosomal recessive tubulopathies characterized by electrolytic imbalance, metabolic alkalosis, sodium wasting and prominent activation of the renin-angiotensin-aldosterone system. Notwithstanding the activation of the renin-angiotensin-aldosterone system, GS/BS are normo-hypotensive and protected from cardiovascular-renal remodeling and therefore can be considered the mirror image, the opposite of hypertension.

Angiotensin II and leukocyte trafficking: New insights for an old vascular mediator. Role of redox-signaling pathways

Inflammation and activation of the immune system are key molecular and cellular events in the pathogenesis of cardiovascular diseases, including atherosclerosis, hypertension-induced target-organ damage, and abdominal aortic aneurysm. Angiotensin II (Ang-II) is the main effector peptide hormone of the renin-angiotensin system. Beyond its role as a potent vasoconstrictor and regulator of blood pressure and fluid homeostasis, Ang-II is intimately involved in the development of vascular lesions in cardiovascular diseases through the activation of different immune cells. The migration of leukocytes from circulation to the arterial subendothelial space is a crucial immune response in lesion development that is mediated through a sequential and coordinated cascade of leukocyte-endothelial cell adhesive interactions involving an array of cell adhesion molecules present on target leukocytes and endothelial cells and the generation and release of chemoattractants that activate and guide leukocytes to sites of emigration. In this review, we outline the key events of Ang-II participation in the leukocyte recruitment cascade, the underlying mechanisms implicated, and the corresponding redox-signaling pathways. We also address the use of inhibitor drugs targeting the effects of Ang-II in the context of leukocyte infiltration in these cardiovascular pathologies, and examine the clinical data supporting the relevance of blocking Ang-II-induced vascular inflammation.

Olmesartan restores the protective effect of remote ischemic perconditioning against myocardial ischemia/reperfusion injury in spontaneously hypertensive rats

OBJECTIVES

Remote ischemic perconditioning is the newest technique used to lessen ischemia/reperfusion injury. However, its effect in hypertensive animals has not been investigated. This study aimed to examine the effect of remote ischemic perconditioning in spontaneously hypertensive rats and determine whether chronic treatment with Olmesartan could influence the effect of remote ischemic perconditioning.

METHODS

Sixty rats were randomly divided into six groups: vehicle-sham, vehicle-ischemia/reperfusion injury, vehicle-remote ischemic perconditioning, olmesartan-sham, olmesartan-ischemia/reperfusion and olmesartan-remote ischemic perconditioning. The left ventricular mass index, creatine kinase concentration, infarct size, arrhythmia scores, HIF-1α mRNA expression, miR-21 expression and miR-210 expression were measured.

RESULTS

Olmesartan significantly reduced the left ventricular mass index, decreased the creatine kinase concentration, limited the infarct size and reduced the arrhythmia score. The infarct size, creatine kinase concentration and arrhythmia score during reperfusion were similar for the vehicle-ischemia/reperfusion group and vehicle-remote ischemic perconditioning group. However, these values were significantly decreased in the olmesartan-remote ischemic perconditioning group compared to the olmesartan-ischemia/reperfusion injury group. HIF-1α, miR-21 and miR-210 expression were markedly down-regulated in the Olmesartan-sham group compared to the vehicle-sham group and significantly up-regulated in the olmesartan-remote ischemic perconditioning group compared to the olmesartan-ischemia/reperfusion injury group.

CONCLUSION

The results indicate that (1) the protective effect of remote ischemic perconditioning is lost in vehicle-treated rats and that chronic treatment with Olmesartan restores the protective effect of remote ischemic perconditioning; (2) chronic treatment with Olmesartan down-regulates HIF-1α, miR-21 and miR-210 expression and reduces hypertrophy, thereby limiting ischemia/reperfusion injury; and (3) recovery of the protective effect of remote ischemic perconditioning is related to the up-regulation of HIF-1α, miR-21 and miR-210 expression.

Effects of olmesartan on endothelial progenitor cell mobilization and function in carotid atherosclerosis

BACKGROUND

Olmesartan is a type of angiotensin II receptor inhibitor that can reduce the incidence of cardiovascular events. However, its role in the function of endothelial progenitor cells in atherosclerosis patients is still unclear. Our study aimed to explore the effects and mechanism of olmesartan on endothelial progenitor cell mobilization and function in carotid atherosclerosis.

MATERIAL/METHODS

Forty carotid atherosclerosis patients were enrolled. Patients were administrated olmesartan 20 mg/day for 3 months. Flow cytometry was used for counting circulating endothelial progenitor cells; colorimetric method was used to measure the serum levels of endothelial nitric oxide synthase and nitric oxide. Cell migration, adhesion, and proliferation capacity, and related signaling pathway were also analyzed. Spearman rank correlation analysis was used to investigate the influence of olmesartan on endothelial progenitor cells and clinical characteristics (e.g., sex, age, blood pressure).

RESULTS

Compared with the control group, the number of circulating endothelial progenitor cells was significantly decreased. Olmesartan can increase circulating endothelial progenitor cells number and the serum levels of eNOS and NO. Furthermore, it can improve cell migration, adhesion, and proliferation capacities. Spearman rank correlation analysis showed there is no relationship between olmesartan promotion effects on endothelial progenitor cell mobilization and the clinical characteristics (P>0.05). P-eNOS and P-Akt expression can be unregulated by RNH-6270 treatment and blocked by LY294002.

CONCLUSIONS

Olmesartan can effectively promote the endothelial progenitor cells mobilization and improve their function in patients with carotid atherosclerosis, independent of basic characteristics. This process relies on the PI3K/Akt/eNOS signaling pathway.

Protective effect of olmesartan against cardiac ischemia/reperfusion injury in spontaneously hypertensive rats

Olmesartan, as a new angiotensin II receptor blocker, has shown beneficial effects on cardiovascular diseases. Nevertheless, the effect of olmesartan on ischemia/reperfusion (I/R) injury in the hypertensive heart has not been investigated. Therefore, the present study aimed to investigate the effect of olmesartan on I/R injury in spontaneously hypertensive rats (SHRs). Experimental groups were designed with a 2×2 factorial design for olmesartan and I/R effects. In the I/R group, the left anterior descending coronary artery (LAD) was ligated for 40 min followed by a 180-min reperfusion. In the sham group, SHRs underwent the same surgical procedure as the I/R group, with the exception that the suture passed under the LAD without being tightened. In the Olm-I/R group, the SHRs received olmesartan (5 mg/kg) for 4 weeks prior to surgery and other procedures were the same as for the I/R group. In the Olm-sham group, the SHRs received olmesartan (5 mg/kg) for 4 weeks prior to surgery and other procedures were the same as for the sham group. Infarct size was measured for the I/R and Olm-I/R groups. Blood pressure (BP), serum creatine kinase (CK), left ventricular mass index (LVMI), high mobility group box 1 (HMGB1) protein expression levels and hypoxia-inducible factor-1α (HIF-1α) mRNA expression levels were measured for all four groups. Olmesartan significantly reduced BP and LVMI in the olmesartan-treated SHRs compared with those in the SHRs that were not treated with olmesartan. HMGB1 and HIF-1α expression levels were significantly decreased in the Olm-sham and Olm-I/R groups compared with those in the sham and I/R groups, respectively. The proportional increase in HIF-1α expression due to I/R was greater in the olmesartan-treated rats than in the untreated rats. Serum CK levels were significantly reduced in the Olm-I/R group compared with those in the I/R group. In conclusion, olmesartan ameliorates left ventricular hypotrophy and protects the heart against I/R injury in addition to lowing BP in SHRs. The protective effect of olmesartan may be partly due to its antioxidative and anti-inflammatory properties.

Effect of olmesartan medoxomil on number and survival of circulating endothelial progenitor cells and calcitonin gene related peptide in hypertensive patients

OBJECTIVE

Injury of vascular endothelium, crucial in vascular disease, is repaired via circulating endothelial progenitor cells (cEPCs). In hypertension, cEPCs number is reduced and function impaired adding further risk for cardiovascular (CV) events. Angiotensin II (Ang II)-induced oxidative stress (OxSt), accelerates cEPCs senescence. Calcitonin gene-related peptide (CGRP), able to prevent and reverse Ang II-induced cEPCs senescence, is reduced in hypertension and stimulated by the antioxidant and anti-inflammatory heme oxygenase (HO)-1. In essential hypertensive patients olmesartan reduced OxSt and markers of CV remodeling and increased HO-1. This study reports in essential hypertensive patients the effect of 6 months treatment with olmesartan on plasma level of CGRP and number and survival of cEPCs.

METHODS AND RESULTS

In 20 essential hypertensive patients treated with olmesartan medoxomil (20  mg per day for 6 months), cEPCs (CD34(+)KDR(+), CD133(+)KDR(+) and CD34(+)CD133(+)KDR(+)) (direct 3-color flow cytometry analysis), apoptosis of cEPCs (CD133(+)KDR(+) cells with Annexin V expression), CGRP determination (ELISA) and HO-1 protein level (western blot) were assessed at baseline and after 3 and 6 months of treatments. Olmesartan normalized blood pressure (P < 0.001), increased cEPCs from baseline (CD34(+)KDR(+): P < 0.003; CD133(+)KDR(+): P < 0.0002; CD34(+)CD133(+)KDR(+): P = 0.0008), reduced cEPCs apoptosis (P < 0.001) and increased CGRP (P < 0.013) and HO-1 (P = 0.039).

CONCLUSION

These results provide a mechanistic rationale for the olmesartan's antioxidant and anti-inflammatory potential translation toward antiatherosclerotic and antiremodeling effects reported on clinical ground.

Hemodynamic and hormonal patterns of untreated essential hypertension in men and women

BACKGROUND

Knowledge of hemodynamic factors accounting for the development of hypertension should help to tailor therapeutic approaches and improve blood pressure control. Few data exist regarding sex differences of hemodynamic factors contributing to hypertension progression among patients with untreated nondiabetic stage I and II prehypertension (PreHyp) as defined by the Joint National Committee-7 guidelines (JNC-7).

METHODS

We utilized noninvasive impedance cardiography, applanation tonometry and plasma measures of angiotensin II, angiotensin (1-7), serum aldosterone, high-sensitivity C-reactive protein (hs-CRP) and cytokine biomarkers of inflammation to characterize the hemodynamic and hormonal profile of 100 patients with untreated hypertension (39 women).

RESULTS

Despite there being no differences between women and men in terms of office blood pressure, heart rate and body mass index, men demonstrated lower values of pulse pressure, systemic vascular resistance, brachial artery pulse wave velocity and augmentation index. In each of the three hypertension categories, the increased blood pressure in men was associated with significant augmentations in stroke volume and cardiac output compared with women. Sex-related hemodynamic differences were associated in women with higher plasma levels of leptin, hs-CRP, plasma angiotensin II and serum aldosterone, and no differences in the serum concentrations of cytokinins. In women but not men, hs-CRP correlated with plasma concentrations of transforming growth factor β1 (TGFβ1) and body weight; in addition, plasma TGFβ1 correlated with levels of serum vascular cell adhesion molecule 1.

CONCLUSION

The impact of sex differences in the hemodynamic factors accounting for the elevation in arterial pressure in subjects with essential hypertension has been poorly characterized or this information is not available. We suggest that this gap in knowledge may adversely influence choices of drug treatment since our study shows for the first time significant differences in the hemodynamic and hormonal mechanisms accounting for the increased blood pressure in women compared to men.

Reduction of Cardiovascular Risk through Angiotensin II Type 1 Receptor Antagonism : Focus on Olmesartan Medoxomil

It is well recognized that angiotensin II is involved in the pathogenesis of hypertension. Less well recognized - until recently, at least - is its involvement in the pathogenesis of atherosclerosis. However, it is now evident that angiotensin II promotes oxidative stress, vascular remodelling, inflammation, and the formation of atherosclerotic lesions. These actions, which are mediated almost exclusively by the angiotensin II type 1 (AT(1)) receptor, can be blocked by administration of angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]). Of the seven ARBs currently in clinical use, olmesartan is one of the most effective. The rapid and consistent antihypertensive efficacy of this drug, which allows a high proportion of patients to achieve their target blood pressure (BP), is associated with beneficial effects on oxidative stress, vascular remodelling, inflammation, and atherosclerotic lesion formation. These effects appear to be independent of the BP-lowering activity of olmesartan. In clinical trials, olmesartan has been shown to control microinflammation in hypertensive patients, to reduce oxidative stress in patients with type 2 diabetes mellitus, and to normalize the wall: lumen ratio of small resistance arteries (a measure of vascular remodelling) in patients with hypertension. Moreover, in a 2-year study involving hypertensive patients with carotid atherosclerosis (the MORE [Multicentre Olmesartan atherosclerosis Regression Evaluation] trial), olmesartan reduced the intima-media thickness of the carotid artery and significantly reduced the volume of large atherosclerotic plaques. These data suggest that olmesartan may reduce cardiovascular risk by simultaneously normalizing BP and reversing the proatherogenic effects of angiotensin II.

Optimal therapeutic strategy for treating patients with hypertension and atherosclerosis: focus on olmesartan medoxomil

Cardiovascular (CV) disease is a major factor in mortality rates around the world and contributes to more than one-third of deaths in the US. The underlying cause of CV disease is atherosclerosis, a chronic inflammatory process that is clinically manifested as coronary artery disease, carotid artery disease, or peripheral artery disease. It has been predicted that atherosclerosis will be the primary cause of death in the world by 2020. Consequently, developing a treatment regimen that can slow or even reverse the atherosclerotic process is imperative. Atherogenesis is initiated by endothelial injury due to oxidative stress associated with CV risk factors including diabetes mellitus, hypertension, cigarette smoking, dyslipidemia, obesity, and metabolic syndrome. Since the renin– angiotensin–aldosterone system (RAAS) plays a key role in vascular inflammatory responses, hypertension treatment with RAAS-blocking agents (angiotensin-converting enzyme inhibitors [ACEIs] and angiotensin II receptor blockers [ARBs]) may slow inflammatory processes and disease progression. Reduced nitric oxide (NO) bioavailability has an important role in the process of endothelial dysfunction and hypertension. Therefore, agents that increase NO and decrease oxidative stress, such as ARBs and ACEIs, may interfere with atherosclerosis. Studies show that angiotensin II type 1 receptor antagonism with an ARB improves endothelial function and reduces atherogenesis. In patients with hypertension, the ARB olmesartan medoxomil provides effective blood pressure lowering, with inflammatory marker studies demonstrating significant RAAS suppression. Several prospective, randomized studies show vascular benefits with olmesartan medoxomil: reduced progression of coronary atherosclerosis in patients with stable angina pectoris (OLIVUS); decreased vascular inflammatory markers in patients with hypertension and micro- (pre-clinical) inflammation (EUTOPIA); improved common carotid intima-media thickness and plaque volume in patients with diagnosed atherosclerosis (MORE); and resistance vessel remodeling in patients with stage 1 hypertension (VIOS). Although CV outcomes were not assessed in these studies, the observed benefits in surrogate endpoints of disease suggest that RAAS suppression with olmesartan medoxomil may potentially have beneficial effects on CV outcomes in these patient populations.

The role of Beta-blockers as first-line therapy in hypertension

National and international guidelines still recommend β-blockers (BBs) as first-line agents in uncomplicated prevention of hypertension. However, it has been shown that BBs reduce blood pressure less than other drugs, specifically with regard to central aortic pressure. More importantly, recent meta-analyses have highlighted that in primary prevention BBs are associated with a relatively weak effect in reducing stroke compared to placebo or no treatment and, compared with other drugs, show evidence of a worse cardiovascular outcome. Several reasons might explain their mild cardioprotective effect, such as their unfavorable metabolic properties, a lack of efficacy on left ventricular hypertrophy regression and endothelial dysfunction, and reduced patient compliance. Thus, the available evidence does not support the use of BBs as first-line drugs in the treatment of uncomplicated hypertension. It remains to be determined whether newer BBs, such as nebivolol and carvedilol, will be more effective than older compounds in improving cardiovascular prognosis.

Optimal therapeutic strategy for treating patients with hypertension and atherosclerosis: focus on olmesartan medoxomil

Cardiovascular (CV) disease is a major factor in mortality rates around the world and contributes to more than one-third of deaths in the US. The underlying cause of CV disease is atherosclerosis, a chronic inflammatory process that is clinically manifested as coronary artery disease, carotid artery disease, or peripheral artery disease. It has been predicted that atherosclerosis will be the primary cause of death in the world by 2020. Consequently, developing a treatment regimen that can slow or even reverse the atherosclerotic process is imperative. Atherogenesis is initiated by endothelial injury due to oxidative stress associated with CV risk factors including diabetes mellitus, hypertension, cigarette smoking, dyslipidemia, obesity, and metabolic syndrome. Since the renin-angiotensin-aldosterone system (RAAS) plays a key role in vascular inflammatory responses, hypertension treatment with RAAS-blocking agents (angiotensin-converting enzyme inhibitors [ACEIs] and angiotensin II receptor blockers [ARBs]) may slow inflammatory processes and disease progression. Reduced nitric oxide (NO) bioavailability has an important role in the process of endothelial dysfunction and hypertension. Therefore, agents that increase NO and decrease oxidative stress, such as ARBs and ACEIs, may interfere with atherosclerosis. Studies show that angiotensin II type 1 receptor antagonism with an ARB improves endothelial function and reduces atherogenesis. In patients with hypertension, the ARB olmesartan medoxomil provides effective blood pressure lowering, with inflammatory marker studies demonstrating significant RAAS suppression. Several prospective, randomized studies show vascular benefits with olmesartan medoxomil: reduced progression of coronary atherosclerosis in patients with stable angina pectoris (OLIVUS); decreased vascular inflammatory markers in patients with hypertension and micro- (pre-clinical) inflammation (EUTOPIA); improved common carotid intima-media thickness and plaque volume in patients with diagnosed atherosclerosis (MORE); and resistance vessel remodeling in patients with stage 1 hypertension (VIOS). Although CV outcomes were not assessed in these studies, the observed benefits in surrogate endpoints of disease suggest that RAAS suppression with olmesartan medoxomil may potentially have beneficial effects on CV outcomes in these patient populations.

Effect of olmesartan on oxidative stress in hypertensive patients: mechanistic support to clinical trials derived evidence

The role of oxidative stress in the pathophysiology of hypertension and target organ damage is widely recognized. Using a molecular biology approach, we report, in essential hypertensive patients, the effect of the angiotensin II type 1 receptor blocker olmesartan on the mononuclear cell (PBMC) protein expression of major elements in the oxidative stress and vascular remodeling-related pathways, p22(phox) and HO-1, along with the phosphorylation state of ERK1/2 and plasma oxidized low-density lipoproteins (oxLDL). Twenty untreated essential hypertensive patients (range blood pressure: 142?156/94?98 mmHg) were treated with olmesartan medoxomil (20 mg/day for 6 months) and blood samples collected at baseline, 3 and 6 months for PBMC p22(phox) and HO-1 protein expression, phosphorylation state of ERK1/2 (western blot) and oxLDL level (ELISA) evaluations. Olmesartan normalized blood pressure since the third month (149 ? 4.7/94.88 ? 1.9 mmHg vs 137.89 ? 2.08/88.44 ? 2.0 at 3 months and vs 135.44 ? 2.18/85.78 ? 1.2 at 6 months, analysis of variance: p < 0.001). p22(phox) protein level declined at 3 months (7.10 ? 2.61 vs 9.32 ? 2.43 densitometric units (d.u.; p < 0.001), further declining at 6 months (4.55 ? 1.26 d.u., p < 0.001). HO-1 levels increased at 3 months (10.87 ? 1.92 vs 7.70 ? 0.71 d.u., p = 0.001) and remained elevated (11.11 ? 1.89 d.u., p = 0.001), without further increase at 6 months. Phosphorylated ERK1/2 declined at 3 months (3.94 ? 1.44 vs 5.62 ? 1.11 d.u., p = 0.001), further declining at 6 months (1.94 ? 0.87, p < 0.001). oxLDL significantly declined at 3 and 6 months. These results demonstrate that olmesartan inhibits oxidative stress. Given the involvement of oxidative stress and its signaling in atherogenesis, and the available evidence of olmesartan's vasoprotective, anti-inflammatory and antiatherosclerotic effects derived from clinical trials in humans, the results of our study provide a mechanistic rationale for the omelsartan's antioxidant and anti-inflammatory potential translation, in the long term, toward the antiatherosclerotic and antiremodeling effects reported on the clinical ground.

Microvascular disease and its role in the brain and cardiovascular system: a potential role for uric acid as a cardiorenal toxin

Arteriolosclerosis (microvascular disease) may have a key role not only in driving salt-sensitive hypertension but also in mediating the development of chronic kidney disease, vascular dementia, stroke and coronary heart disease. In this paper, we review the evidence that these latter conditions result from the altered autoregulation that occurs when arterioles become diseased. We also discuss the increasing evidence that dietary intake of sugars rich in fructose may be driving the development of microvascular disease as a consequence of raising intracellular uric acid. We hypothesize that the treatment of microvascular disease may require a multifaceted approach by utilizing agents which aim at blocking of the renin-angiotensin system, reducing oxidative stress, stimulating endothelial nitric oxide production and lowering uric acid levels. Paradoxically, agents that only stimulate nitric oxide, such as oestrogens, may increase the risk of poor outcomes if microvascular disease is not reversed.

Role of olmesartan in combination therapy in blood pressure control and vascular function

Angiotensin receptor blockers have emerged as a first-line therapy in the management of hypertension and hypertension-related comorbidities. Since national and international guidelines have stressed the need to control blood pressure to <140/90 mmHg in uncomplicated hypertension and <130/80 mmHg in those with associated comorbidities such as diabetes or chronic kidney disease, these goal blood pressures can only be achieved through combination therapy. Of several drugs that can be effectively combined to attain the recommended blood pressure goals, fixed-dose combinations of angiotensin receptor blockers and the calcium channel blocker amlodipine provide additive antihypertensive effects associated with a safe profile and increased adherence to therapy. In this article, we review the evidence regarding the beneficial effects of renin–angiotensin system blockade with olmesartan medoxomil and amlodipine in terms of blood pressure control and improvement of vascular function and target organ damage.

Why beta-blockers should not be used as first choice in uncomplicated hypertension

In the past 4 decades, beta blockers (BBs) have been widely used in the treatment of uncomplicated hypertension and are still recommended as first-line agents in national and international guidelines. Their putative cardioprotective properties, however, derive from the extrapolation into primary prevention of data relative to the reduction of mortality observed in the 1970s in patients with previous myocardial infarctions. In the past 5 years, a critical reanalysis of older trials, together with several meta-analyses, has shown that in patients with uncomplicated hypertension BBs exert a relatively weak effect in reducing stroke compared to placebo or no treatment, do not have any protective effect with regard to coronary artery disease and, compared to other drugs, such as calcium channel blockers, renin-angiotensin-aldosterone system inhibitors or thiazide diuretics, show evidence of worse outcomes, particularly with regard to stroke. Several reasons can explain their reduced cardioprotection: their suboptimal effect in lowering blood pressure compared to other drugs; their "pseudoantihypertensive" efficacy (failure to lower central aortic pressure); their undesirable adverse effects, which reduce patients' compliance; their unfavorable metabolic effects; their lack of an effect on regression of left ventricular hypertrophy and endothelial dysfunction. In conclusion, the available evidence does not support the use of BBs as first-line drugs in the treatment of hypertension. Whether newer BBs, such as nebivolol and carvedilol, which show vasodilatory properties and a more favorable hemodynamic and metabolic profile, will be more efficacious in reducing morbidity and mortality remains to be determined.

Impact of olmesartan on blood pressure, endothelial function, and cardiovascular outcomes

The vascular endothelium, the largest "organ" in the body, synthesizes and releases a wide spectrum of vasoactive substances into the circulation. Endothelial dysfunction links hypertension and other cardiovascular (CV) risk factors that promote the development of atherosclerotic plaque, CV disease, and fatal and nonfatal CV events. Blood pressure (BP) reduction is the most effective way to reduce CV risk in patients with hypertension, but it is unknown whether endothelial dysfunction is a cause or consequence of hypertension. Renin-angiotensin-aldosterone system blockers improve endothelial function and have favorable vascular, metabolic, cardiac, and renoprotective effects that are independent of BP reduction. Olmesartan effectively reduces BP and also has vasoprotective properties, including reductions in endothelial dysfunction and inflammation, prevention of microalbuminuria, and reversal of vascular remodeling. Large-scale, long-term studies are needed to confirm that olmesartan has vasoprotective effects that are independent of BP control and to determine whether these pleiotropic effects translate into improved CV disease outcomes.

Olmesartan for the treatment of arterial hypertension

Angiotensin-receptor blockers (ARBs) are an important class of agents used for the treatment of arterial hypertension. Olmesartan medoxomil, the seventh latest ARB approved by the US FDA, is an oral, once-daily, AT(1)-receptor selective ARB with high receptor affinity. Pharmacologically, it acts as a competitive and insurmountable Ang II antagonist with linear pharmacokinetics and without cytochrome P450 interaction. The drug is licensed for the treatment of arterial hypertension alone or in combination with other antihypertensive agents. Olmesartan has demonstrated its dose-dependent inhibitory effect on Ang I-induced blood pressure responses between 10 and 80 mg in Phase II studies. These results, confirmed in an international clinical trial programme covering over 3000 hypertensive patients in numerous studies, demonstrated rapid blood pressure-lowering effects within 1 week. A daily oral dose of 20 mg olmesartan is considered to be the optimal dose. In clinical trials and postmarketing studies, olmesartan has been shown to be safe and well tolerated with an adverse event profile similar to the placebo. Active comparative studies demonstrated either similar or superior efficacy of olmesartan compared with other ARBs, angiotensin-converting enzymes inhibitors, beta-blockers or calcium-channel blockers. Besides its antihypertensive efficacy, olmesartan was shown in clinical trials to reduce vascular microinflammation, decrease intrarenal vascular resistance, significantly reduce vascular remodeling of small resistance arteries and exert antiatherosclerotic effects by significantly reducing the volume of large atherosclerotic plaques.

Angiotensin receptor blocker and dihydropyridine calcium channel blocker combinations: an emerging strategy in hypertension therapy

Hypertension is a leading contributor to the burden of cardiovascular disease. The importance of lowering blood pressure (BP) to reduce the risk of cardiovascular events has been demonstrated in numerous clinical trials. Most patients require combination antihypertensive therapy utilizing agents from complementary drug classes to achieve BP goals. A calcium channel blocker (CCB)/angiotensin receptor blocker (ARB) combination is a rational approach for such an antihypertensive strategy. Benefits of CCB/ARB combination therapy include additive BP-lowering effects and lower incidences of adverse events (AEs). These agents demonstrate benefits associated with their respective drug classes. The ARBs confer stroke protection, renal protection, and tolerability similar to placebo, without dose-related symptomatic and metabolic AEs, while CCBs are beneficial in reducing stroke and treating angina and cardiac ischemia. The efficacy of this combination has been recently investigated in clinical trials wherein amlodipine was combined with olmesartan medoxomil or valsartan. This article discusses the rationale for using CCB/ARB combinations in patients with hypertension.

Effect of angiotensin receptor blockade on endothelial function: focus on olmesartan medoxomil

Endothelial dysfunction is the common link between cardiovascular disease risk factors and the earliest event in the cascade of incidents that results in target organ damage. Angiotensin II, the terminal pressor effector arm of the renin-angiotensin-aldosterone system, increases blood pressure (BP) by vasoconstriction and sodium and fluid retention, and has a pro-oxidative action that induces endothelial dysfunction and contributes to vascular remodeling. Angiotensin receptor blockers (ARBs) reduce BP and morbidity and mortality in patients with hypertension, ventricular hypertrophy, diabetes mellitus, and renal disease. Olmesartan medoxomil is a long-acting, well-tolerated, effective ARB that prevents or reverses endothelial dysfunction in animal models of atherosclerosis, hypertension, diabetes, nephropathy, and retinopathy. Olmesartan medoxomil, a prodrug of olmesartan approved for the treatment of hypertension, has been shown to ameliorate endothelial dysfunction in patients with hypertension or diabetes. In randomized studies, the drug reduces vascular inflammation and the volume of large atherosclerotic plaques, increases the number of regenerative endothelial progenitor cells in the peripheral circulation, improves endothelium-dependent relaxation, and restores the normal resistance vessel morphology. Importantly, the impact of olmesartan medoxomil on endothelial dysfunction is thought to be independent of BP lowering.

Review: New techniques for assessment of vascular function

The noninvasive measurement of hemodynamic variables associated with hypertension and cardiovascular disease processes needs to be recognized as a viable adjunct to clinical practice. This review traces the history of the inception and development of noninvasive measurement of hemodynamic variable. It then identifies well established, useful, and available devices, and then notes clinical studies verifying the clinical relevance of these measurements. Given the need to intervene earlier in the course of cardiovascular disease processes, tools are needed to assist the medical team to evaluate, prognosticate, and guide their patient's therapy correctly. It is the goal of this review to heighten the awareness and enhance and encourage the implementation of these devices in our armamentarium for the betterment of our patient's health.