Angiotensin receptor blockade decreases markers of vascular inflammation

The Tissue Renin-Angiotensin System and Its Role in the Pathogenesis of Major Human Diseases: Quo Vadis?

Evidence has arisen in recent years suggesting that a tissue renin-angiotensin system (tRAS) is involved in the progression of various human diseases. This system contains two regulatory pathways: a pathological pro-inflammatory pathway containing the Angiotensin Converting Enzyme (ACE)/Angiotensin II (AngII)/Angiotensin II receptor type 1 (AGTR1) axis and a protective anti-inflammatory pathway involving the Angiotensin II receptor type 2 (AGTR2)/ACE2/Ang1–7/MasReceptor axis. Numerous studies reported the positive effects of pathologic tRAS pathway inhibition and protective tRAS pathway stimulation on the treatment of cardiovascular, inflammatory, and autoimmune disease and the progression of neuropathic pain. Cell senescence and aging are known to be related to RAS pathways. Further, this system directly interacts with SARS-CoV 2 and seems to be an important target of interest in the COVID-19 pandemic. This review focuses on the involvement of tRAS in the progression of the mentioned diseases from an interdisciplinary clinical perspective and highlights therapeutic strategies that might be of major clinical importance in the future.

Are losartan and imatinib effective against SARS-CoV2 pathogenesis? A pathophysiologic-based in silico study

Proposing a theory about the pathophysiology of cytokine storm in COVID19, we were to find the potential drugs to treat this disease and to find any effect of these drugs on the virus infectivity through an in silico study. COVID-19-induced ARDS is linked to a cytokine storm phenomenon not explainable solely by the virus infectivity. Knowing that ACE2, the hydrolyzing enzyme of AngII and SARS-CoV2 receptor, downregulates when the virus enters the host cells, we hypothesize that hyperacute AngII upregulation is the eliciting factor of this ARDS. We were to validate this theory through reviewing previous studies to figure out the role of overzealous activation of AT1R in ARDS. According to this theory losartan may attenuate ARDS in this disease. Imatinib, has previously been elucidated to be promising in modulating lung inflammatory reactions and virus infectivity in SARS and MERS. We did an in silico study to uncover any probable other unconsidered inhibitory effects of losartan and imatinib against SARS-CoV2 pathogenesis. Reviewing the literature, we could find that over-activation of AT1R could explain precisely the mechanism of cytokine storm in COVID19. Our in silico study revealed that losartan and imatinib could probably: (1) decline SARS-CoV2 affinity to ACE2. (2) inhibit the main protease and furin, (3) disturb papain-like protease and p38MAPK functions. Our reviewing on renin-angiotensin system showed that overzealous activation of AT1R by hyper-acute excess of AngII due to acute downregulation of ACE2 by SARS-CoV2 explains precisely the mechanism of cytokine storm in COVID-19. Besides, based on our in silico study we concluded that losartan and imatinib are promising in COVID19.

Studying the Effects of Systemic Inflammatory Markers and Drugs on AVF Longevity through a Novel Clinical Intelligent Framework

Although arteriovenous fistula is the preferred vascular access method, it has challenges in three phases of planning, maturation, and maintenance. We looked at the root of fistula challenges in the maintenance phase and found traces of inflammation. Accordingly, we investigated the role of systemic inflammation in this phase to understand its effects on post-maturation function and extract knowledge to help extend fistula longevity. Previous studies on longevity of fistula have focused entirely on statistical tests, and since they put limitations on data, we also used a data mining framework for data analysis. For prediction, we used Decision Tree, Random Forest, and Support Vector Machines, and for inferential analysis, we used Wilcoxon and Chi-squared tests. We analyzed the archived data of 119 hemodialysis patients. In these data, independent variables were serum inflammatory markers, serum metabolic values, anti-inflammatory drugs, and demographic characteristics, and the dependent variable was fistula longevity separated in classes of equal to or greater than four and less than four years. Both predictive and inferential approaches have shown that serum inflammatory markers had no significant involvement in fistula longevity, but some anti-inflammatory drugs were effective. The results have shown that blood tests and drug variables, alone or together, could predict longevity class by 100% accuracy. This prediction can help surgeons make better decisions in selecting patients for fistula creation. Also, the extracted knowledge can provide guidelines for post-maturation disorders.

Neprilysin Inhibitor-Angiotensin II Receptor Blocker Combination Therapy (Sacubitril/valsartan) Suppresses Atherosclerotic Plaque Formation and Inhibits Inflammation in Apolipoprotein E- Deficient Mice

We assessed the effects of the sacubitril/valsartan combination drug (LCZ696), in comparison to valsartan alone, on the progression of atherosclerotic plaque formation and inflammatory gene expression in apolipoprotein E- deficient mice (apoE^−/− mice). Seventy-two apoE^−/− mice were fed a western diet and a constrictive silastic tube was used to elicit carotid lesion formation. The animals were separated into a control group, a valsartan group or an LCZ696 group (n = 24 in each group). Plaques in the carotid artery were harvested 12 weeks later for histological examination. The levels of pro-inflammatory genes in the plasma and lesions were detected using real-time PCR and ELISA. Valsartan or LCZ696 treatment remarkably inhibited the expression of pro-inflammatory genes, including interleukin-6, matrix metalloproteinase-8 and monocyte chemotactic protein-1, in comparison with the control group. Meanwhile, both valsartan and LCZ696 suppressed the formation of atherosclerotic plaques by decreasing plaque lipid content and cross-sectional plaque area and increasing the content of plaque collagen and fibrous cap thickness. In particular, LCZ696 performed the best in suppressing atherosclerosis and inhibiting the level of pro-inflammatory genes. LCZ696 significantly ameliorated atherosclerosis and inflammation in apoE^−/− mice compared with valsartan.

The potential therapeutic use of renin-angiotensin system inhibitors in the treatment of inflammatory diseases

Inflammation is a normal part of the immune response to injury or infection but its dysregulation promotes the development of inflammatory diseases, which cause considerable human suffering. Nonsteroidal anti-inflammatory agents are the most commonly prescribed agents for the treatment of inflammatory diseases, but they are accompanied by a broad range of side effects, including gastrointestinal and cardiovascular events. The renin-angiotensin system (RAS) is traditionally known for its role in blood pressure regulation. However, there is increasing evidence that RAS signaling is also involved in the inflammatory response associated with several disease states. Angiotensin II increases blood pressure by binding to angiotensin type 1 (AT₁ ) receptor, and direct renin inhibitors, angiotensin-converting enzyme (ACE) inhibitors and AT₁ receptor blockers (ARBs) are clinically used as antihypertensive agents. Recent data suggest that these drugs also have anti-inflammatory effects. Therefore, this review summarizes these recent findings for the efficacy of two of the most widely used antihypertensive drug classes, ACE inhibitors and ARBs, to reduce or treat inflammatory diseases such as atherosclerosis, arthritis, steatohepatitis, colitis, pancreatitis, and nephritis.

Angiotensin II/Angiotensin (1-7) ratio and 24-h blood pressure throughout the menstrual cycle and in women using oral contraceptives

BACKGROUND

Women using oral contraceptives have higher ambulatory blood pressures (BPs) than other women. We sought to learn whether this was associated with an alteration in the balance of angiotensin II (Ang)/Ang (1-7) and whether this ratio and BP remained constant throughout the menstrual cycle.

METHOD

In total, 30 (15 ovulatory, 15 taking oral contraceptives) healthy, normotensive women aged 18-30 years were studied. The ovulatory group was assessed within days 1-5 (follicular phase) and 19-23 (luteal phase) and the oral contraceptive group within days 19-23. Peripheral, central and 24-h BP, vascular wall stiffness, and body composition were measured along with plasma estradiol, progesterone, renin, aldosterone, Ang II, and Ang (1-7) concentrations.

RESULTS

In ovulatory women plasma renin activity (P < 0.001), renin concentration (P < 0.01) and aldosterone (P < 0.05) were higher in the luteal than follicular phase, whereas BP, Ang II and the Ang II/Ang (1-7) ratio remained constant. In women taking oral contraceptives, plasma renin activity (P < 0.001) and concentration (P < 0.01) were higher than in follicular phase ovulatory women whereas 24-h BP, Ang II, Ang (1-7), and the Ang II/Ang (1-7) ratio (P < 0.01) were higher than in both phases of the ovulatory group. However, there was no significant correlation between BP and the Ang II/Ang (1-7) ratio.

CONCLUSION

This study confirms that BP is constant throughout the normal menstrual cycle along with a constant balance between the vasoconstrictor (Ang II) and vasodilator [Ang (1-7)] arms of the renin-Ang-aldosterone system. Women taking oral contraceptives have a higher Ang II/Ang (1-7) ratio associated with their BP elevation although no causal relationship has been found.

Renin-Angiotensin System Inhibitors vs Other Antihypertensives in Hypertensive Blacks: A Meta-Analysis

The purpose of this study was to assess the effects of renin-angiotensin system (RAS) inhibitors vs other antihypertensive agents on cardiovascular outcomes in hypertensive black patients. The authors performed a systematic review and meta-analysis of studies that compared the effects of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) with calcium channel blockers (CCBs), diuretics, and β-blockers in hypertensive black patients on cardiovascular outcomes. A total of 38,983 patients with a mean age of 60 years and mean follow-up of 4 years were included in our meta-analysis. No significant differences were found in all-cause mortality, myocardial infarction, heart failure, and cardiovascular mortality rates among patients treated with RAS inhibitors compared with CCBs, diuretics, and β-blockers. The incidence of stroke was significantly increased in patients treated with RAS inhibitors compared with CCBs (odds ratio, 1.56; 95% confidence interval, 1.31-1.87 [P<.00001]; I2 =0%) and diuretics (odds ratio, 1.59; 95% confidence interval, 1.16-2.17 [P=.004]; I2 =56%) but not β-blockers.

Preclinical and Clinical Studies on Antioxidative, Antihypertensive and Cardioprotective Effect of Marine Proteins and Peptides-A Review

High seafood consumption has traditionally been linked to a reduced risk of cardiovascular diseases, mainly due to the lipid lowering effects of the long chained omega 3 fatty acids. However, fish and seafood are also excellent sources of good quality proteins and emerging documentation show that, upon digestion, these proteins are sources for bioactive peptides with documented favorable physiological effects such as antioxidative, antihypertensive and other cardioprotective effects. This documentation is mainly from in vitro studies, but also animal studies are arising. Evidence from human studies evaluating the positive health effects of marine proteins and peptides are scarce. In one study, a reduction in oxidative stress after intake of cod has been documented and a few human clinical trials have been performed evaluating the effect on blood pressure. The results are, however, inconclusive. The majority of the human clinical trials performed to investigate positive health effects of marine protein and lean fish intake, has focused on blood lipids. While some studies have documented a reduction in triglycerides after intake of lean fish, others have documented no effects.

Vascular endothelium - Gatekeeper of vessel health

The vascular endothelium is an interface between the blood stream and the vessel wall. Changes in this single cell layer of the artery wall are believed of primary importance in the pathogenesis of vascular disease/atherosclerosis. The endothelium responds to humoral, neural and especially hemodynamic stimuli and regulates platelet function, inflammatory responses, vascular smooth muscle cell growth and migration, in addition to modulating vascular tone by synthesizing and releasing vasoactive substances. Compromised endothelial function contributes to the pathogenesis of cardiovascular disease; endothelial 'dysfunction' is associated with risk factors, correlates with disease progression, and predicts cardiovascular events. Therapies for atherosclerosis have been developed, therefore, that are directed towards improving endothelial function.

Aspirin downregulates angiotensin type 1 receptor transcription implications in capillary formation from endothelial cells

Aspirin [acetyl salicylic acid (ASA)] inhibits nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and reactive oxygen species generation, a pathway that underlies formation of new capillaries (angiogenesis). Angiotensin II (Ang II) participates in angiogenesis by activating type 1 receptor (AT1R). We examined if ASA would inhibit AT1R transcription, which requires NADPH oxidase, and thereby new capillary formation. Human umbilical vein endothelial cells were cultured in Matrigel and treated with Ang II with and without ASA. Expression of AT1R and NADPH oxidase was measured by quantitative polymerase chain reaction. Ang II in low concentrations induced AT1R messenger RNA and new capillary formation. ASA and its salicylic acid (SA) moiety both suppressed Ang II-mediated AT1R and vascular endothelial growth factor expression and the subsequent new capillary formation. Of note, the AT1R blocker losartan prevented new capillary formation. ASA and SA also suppressed NADPH oxidase (p22, p47, p67, and gp91 messenger RNA) expression. These observations suggest that ASA can inhibit Ang II-induced capillary formation in part via blocking NADPH oxidase and AT1R transcription. Because SA moiety had similar effect as ASA on AT1R expression, we suggest that the effect of ASA on new capillary formation is mediated by its SA moiety.

Selectins and Associated Adhesion Proteins in Inflammatory disorders

Inflammation is defined as the normal response of living tissue to injury or infection. It is important to emphasize two components of this definition. First, that inflammation is a normal response and, as such, is expected to occur when tissue is damaged. Infact, if injured tissue does not exhibit signs of inflammation this would be considered abnormal and wounds and infections would never heal without inflammation. Secondly, inflammation occurs in living tissue, hence there is need for an adequate blood supply to the tissues in order to exhibit an inflammatory response. The inflammatory response may be triggered by mechanical injury, chemical toxins, and invasion by microorganisms, and hypersensitivity reactions. Three major events occur during the inflammatory response: the blood supply to the affected area is increased substantially, capillary permeability is increased, and leucocytes migrate from the capillary vessels into the surrounding interstitial spaces to the site of inflammation or injury. The inflammatory response represents a complex biological and biochemical process involving cells of the immune system and a plethora of biological mediators. Cell-to-cell communication molecules such as cytokines play an extremely important role in mediating the process of inflammation. Inflammation and platelet activation are critical phenomena in the setting of acute coronary syndromes. An extensive exposition of this complex phenomenon is beyond the scope of this article (Rankin 2004).

Combination of fluvastatin and losartan relieves atherosclerosis and macrophage infiltration in atherosclerotic plaques in rabbits

AIM

To investigate whether the combination of fluvastatin and losartan synergistically relieve atherosclerosis and plaque inflammation induced by a high-cholesterol diet in rabbits.

METHODS

Atherosclerosis was induced with a high-cholesterol diet for 3 months in 36 New Zealand white rabbits. The animals were randomly divided into model group, fluvastatin (10 mg·kg(-1)·d(-1)) group, losartan (25 mg·kg(-1)·d(-1)) group, and fluvastatin plus losartan group. After the 16-week treatments, the blood samples the animals were collected, and the thoracic aortas were examined immunohistochemically. The mRNA and protein expression levels of monocyte chemotactic protein-1 (MCP-1) were measured using RT-PCR and Western blot.

RESULTS

Compared to the treatment with losartan or fluvastatin alone, the combined treatment did not produce higher efficacy in reduction of blood cholesterol level. However, the combination did synergistically decrease the intimal and media thickness of thoracic aortas with significantly reduced macrophage infiltration and MCP-1 expression in the plaques.

CONCLUSION

The combined treatment with losartan and fluvastatin significantly inhibited atherosclerotic progress and reduced inflammation associated with atherosclerotic plaques.

Angiotensin II modulates interleukin-1β-induced inflammatory gene expression in vascular smooth muscle cells via interfering with ERK-NF-κB crosstalk

Angiotensin II is implicated in cardiovascular diseases, which is associated with a role in increasing vascular inflammation. The present study investigated how angiotensin II modulates vascular inflammatory signaling and expression of inducible nitric oxide synthase (iNOS) and vascular cell adhesion molecule (VCAM)-1. In cultured rat aortic vascular smooth muscle cells (VSMCs), angiotensin II suppressed interleukin-1β-induced prolonged phosphorylation of extracellular signal-regulated kinase (ERK) and ribosomal S6 kinase (RSK)-1, and nuclear translocation of nuclear factor (NF)-κB, leading to decreased iNOS but enhanced VCAM-1 expression, associated with an up-regulation of mitogen-activated protein kinase phosphatase-1 expression. Knock-down of RSK1 selectively down regulated interleukin-1β-induced iNOS expression without influencing VCAM-1 expression. In vivo experiments showed that interleukin-1β, iNOS, and VCAM-1 expression were detectable in the aortic arches of both wild-type and apolipoprotein E-deficient (ApoE(-/-)) mice. VCAM-1 and iNOS expression were higher in ApoE(-/-) than in wild type mouse aortic arches. Angiotensin II infusion (3.2 mg/kg/day, for 6 days, via subcutaneous osmotic pump) in ApoE(-/-) mice enhanced endothelial and adventitial VCAM-1 and iNOS expression, but reduced medial smooth muscle iNOS expression associated with reduced phosphorylation of ERK and RSK-1. These results indicate that angiotensin II can differentially modulate inflammatory gene expression in aortic smooth muscle cells through influencing ERK-NF-κB crosstalk, which may contribute to angiotensin II-induced inflammatory disorders related to cardiovascular diseases.

AT1 receptor antagonist candesartan attenuates genomic damage in peripheral blood lymphocytes of patients on maintenance hemodialysis treatment

BACKGROUND

Angiotensin II (ANG II) and advanced glycation end products (AGEs) exert genotoxic effects in vitro which were prevented by the ANG II type 1 (AT1) receptor blocker, candesartan. In end-stage renal disease (ESRD) the incidence of genomic damage is increased. A stimulation of the renin-angiotensin system and accumulation of AGEs could be involved.

METHODS

We tested whether oral co-administration of candesartan modulates enhanced DNA damage in ESRD patients. Fifteen maintenance hemodialysis (MHD) patients with mild hypertension were treated with candesartan for 4.5 months. Fourteen MHD patients served as conventionally treated uremic controls. DNA damage was measured as micronucleus frequency (MNF) in peripheral blood lymphocytes and evaluated three times before candesartan therapy and afterwards every 6 weeks.

RESULTS

Compared to 14 healthy controls, MNF at baseline was significantly elevated in MHD patients. While in the conventionally treated MHD patients the enhanced DNA damage persisted, the co-administration of candesartan ameliorated the genomic damage significantly and independently of blood pressure changes.

CONCLUSION

Blockade of AT1 receptors with candesartan can reduce DNA damage in MHD patients. Long-term studies in larger patient groups are needed to investigate whether the improved genomic damage lowers atherosclerotic complications and cancer development.

Significance of pigment epithelium-derived factor levels with angiotensin II type 1 receptor blockers in patients with successful coronary stent implantation

Pigment epithelium-derived factor (PEDF) and pentosidine have received growing attention as sensitive biomarkers of the progression of atherosclerosis. The present study was performed to evaluate the utility of these biomarkers for assessing the effects of angiotensin II type 1 receptor blockers (ARBs). Sixty-three patients with coronary artery disease (CAD) following successful stent implantation were divided into an ARB group (n = 50), who initially received valsartan or olmesartan immediately following stent implantation, and a non-ARB group (n = 13) according to their blood pressure (BP) at baseline. Measurement of BP and blood sampling was performed prior to (at baseline) and 6-8 months following stent implantation (at follow-up). There were no significant differences in the baseline characteristics between the groups. Although there were no differences in the percentage of diameter re-stenosis between the groups, the BP level in the ARB group at follow-up showed a significant reduction and reached the target BP. The levels of plasma PEDF were significantly increased at follow-up in the ARB group, but not in the non-ARB group, while there were no differences in the levels of pentosidine between the groups. Changes in BP (ΔBP = BP at follow-up minus BP at baseline) were not associated with ΔPEDF. In conclusion, PEDF may be a useful biomarker for assessing the effects of ARBs independent of a reduction in BP.

Local bone marrow Renin-Angiotensin system and atherosclerosis

Local hematopoietic bone marrow (BM) renin-angiotensin system (RAS) affects the growth, production, proliferation differentiation, and function of hematopoietic cells. Angiotensin II (Ang II), the dominant effector peptide of the RAS, regulates cellular growth in a wide variety of tissues in pathobiological states. RAS, especially Ang II and Ang II type 1 receptor (AT1R), has considerable proinflammatory and proatherogenic effects on the vessel wall, causing progression of atherosclerosis. Recent investigations, by analyzing several BM chimeric mice whose BM cells were positive or negative for AT1R, disclosed that AT1R in BM cells participates in the pathogenesis of atherosclerosis. Therefore, AT1R blocking not only in vascular cells but also in the BM could be an important therapeutic approach to prevent atherosclerosis. The aim of this paper is to review the function of local BM RAS in the pathogenesis of atherosclerosis.

Impact of therapy with statins, beta-blockers and angiotensin-converting enzyme inhibitors on plasma myeloperoxidase in patients with coronary artery disease

PURPOSE

The present study investigated whether therapy with statins, beta-blockers and angiotensin-converting enzyme (ACE) inhibitors on admission affects the plasma level of myeloperoxidase (MPO) in patients with coronary artery disease (CAD).

METHODS

This study included a consecutive series of 680 patients with angiographically confirmed CAD: 382 patients with stable CAD, 107 patients with unstable angina and 191 patients with ST-segment elevation acute myocardial infarction. Blood samples for MPO measurement were taken before angiography prior to heparin administration.

RESULTS

On admission, 316 patients were receiving statins, 432 patients were receiving beta-blockers and 354 patients were receiving ACE inhibitors. MPO level was: 65.5 [48.8-101.6] μg/L among patients on statin therapy versus 86.7 [56.0-159.9] μg/L among patients without statin therapy (P < 0.001); 68.1 [50.1-105.1] μg/L among patients on beta-blocker therapy versus 97.3 [56.0-181.9] μg/L among patients without beta-blocker therapy (P < 0.001) and 65.5 [49.2-102.0] μg/L among patients receiving ACE inhibitors versus 92.0 [56.1-171.1] μg/L among patients not receiving ACE inhibitors on admission (P < 0.001). The MPO-lowering effect of these drugs was observed only in patients with acute coronary syndrome but not in patients with stable CAD. The multivariable analysis, adjusting for cardiovascular risk factors, clinical variables and concomitant therapy identified beta-blockers on admission as an independent correlate of lower MPO levels (P = 0.016).

CONCLUSIONS

In patients with symptomatic CAD, beta-blocker therapy on admission was independently associated with lower levels of plasma MPO. Pre-admission therapy with statins, beta-blockers or ACE inhibitors reduced MPO levels in patients with acute coronary syndromes, but not in patients with stable CAD.

Targeting inflammation to slow or delay functional decline: where are we?

The role of inflammation in the pathophysiology of chronic age-related diseases is increasingly recognized, and inflammation could represent the common pathway linking diseases and disability. Thus, targeting inflammation could represent a useful strategy at preventing or delaying functional decline. In this paper we review recent evidence suggesting that selected drugs, such as statins, fibrates, angiotensin converting enzyme-inhibitors and angiotensin receptor blockers, and physical exercise may be able to contrast functional decline by blunting inflammation. Results from randomized trials investigating the effects of physical activity programs on inflammation and functional decline is still limited, and further investigations are warranted.

Blocking the renin-angiotensin system: dual- versus mono-therapy

The renin-angiotensin system (RAS) plays an important role in the pathogenesis of cardiovascular disease. One of the effects of the activated RAS is target-organ damage, in part due to their effects on causing hypertension. Blocking angiotensin-converting enzyme (ACE) with inhibitors has been shown to attenuate the pathological effects of the RAS. Clinical trials have shown that ACE inhibition improves outcomes in the prevention of acute myocardial infarction, lowering the morbidity and mortality in congestive heart failure, and attenuates renal dysfunction. There is recent evidence to show that angiotensin receptor blockers (ARBs) have similar efficacy to ACE inhibitors in reducing cardiovascular outcomes. The wealth of information obtained regarding the beneficial effects of RAS inhibition on clinical outcome has been focused on monotherapy with either ARB or ACE inhibition. Evidence from some trials suggests that better overall inhibition of RAS by dual therapy may improve clinical outcomes. Combination therapy has been shown to be beneficial in patients with congestive heart failure or renal disease. The Valsartan in Acute Myocardial Infarction Trial (VALIANT) trial showed equal benefit of either ARB or ACE inhibition with reduction in primary end points in postmyocardial infarction patients, but there was no further benefit from dual therapy in reducing outcomes. In the recent ONTARGET study, there was further evidence that ARBs are equal to ACE inhibitors in reducing cardiovascular events. In Ongoing Telmisartan, Ramipril, or Both in Patients at High Risk for Vascular Events (ONTARGET), combined RAS blockade did not have any added benefit but resulted in increased risk of adverse outcomes. In the Candesartan in Heart Failure (CHARM) and the Valsartan Heart Failure Trial (Val-HeFT) trials of patients with severe heart failure, the addition of an ARB to an ACE inhibitor reduced cardiac mortality and lowered hospital admissions. Whether or not dual therapy is beneficial in patients with diabetic renal failure should be clarified by future studies. Overall, patients receiving dual therapy, if clinically justified, should be monitored closely for potential adverse effects.

Safety and efficacy of antihypertensive therapy with add-on angiotensin II type 1 receptor blocker after successful coronary stent implantation

This study was performed to evaluate the safety and efficacy of additional antihypertensive therapy with angiotensin II type 1 receptor blocker (ARB; olmesartan or valsartan) after successful stent implantation in patients with coronary artery disease (CAD). Fifty patients with CAD after successful stent implantation were included in this study. They were divided into an ARB group, which initially received olmesartan (n=20, 14+/-8 mg day(-1)) or valsartan (n=20, 60+/-23 mg day(-1)) immediately after stent implantation, and a non-ARB group (n=10) according to their blood pressure (BP). Follow-up coronary angiography, measurement of BP and blood sampling were performed before (at baseline) and 6-8 months after stent implantation (at follow-up). There were no significant differences in the baseline characteristics between the groups, except for BP. Although there were no changes in % diameter restenosis between the groups, the BP level in the ARB group at follow-up showed a significant reduction (125+/-12/69+/-9 mm Hg) and reached the target BP. There were no critical adverse effects in the ARB group throughout the study period. In addition, serum high-sensitive C-reactive protein (hs-CRP) and pentraxin 3 were significantly decreased in the ARB group but not in the non-ARB group. Although olmesartan and valsartan induced similar BP-lowering effects, olmesartan but not valsartan induced a significant decrease in hs-CRP, but did not increase serum uric acid. In conclusion, antihypertensive therapy with add-on low-dose ARB after stent implantation was safe and achieved the target BP. In particular, olmesartan had an anti-inflammatory effect.

The renin-angiotensin system modulates inflammatory processes in atherosclerosis: evidence from basic research and clinical studies

Recent evidence shows that the renin-angiotensin system is a crucial player in atherosclerotic processes. The regulation of arterial blood pressure was considered from its first description of the main mechanism involved. Vasoconstriction (mediated by angiotensin II) and salt and water retention (mainly due to aldosterone) were classically considered as pivotal proatherosclerotic activities. However, basic research and animal studies strongly support angiotensin II as a proinflammatory mediator, which directly induces atherosclerotic plaque development and heart remodeling. Furthermore, angiotensin II induces proatherosclerotic cytokine and chemokine secretion and increases endothelial dysfunction. Accordingly, the pharmacological inhibition of the renin-angiotensin system improves prognosis of patients with cardiovascular disease even in settings of normal baseline blood pressure. In the present review, we focused on angiotensin-convertingenzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and renin inhibitors to update the direct activities of the renin-angiotensin system in inflammatory processes governing atherosclerosis.

The effect of angiotensin receptor blockers on C-reactive protein and other circulating inflammatory indices in man

Anti-inflammatory properties may contribute to the pharmacological effects of angiotensin II receptor blockers (ARBs), a leading therapeutic class in the management of hypertension and related cardiovascular and renal diseases. That possibility, supported by consistent evidence from in-vitro and animal studies showing pro-inflammatory properties of angiotensin II, has been evaluated clinically by measuring the effect of ARBs on C-reactive protein and other circulating indices of inflammation (e-selectin, adhesion molecules, interleukin-6, tissue necrosis factor-alpha, monocyte chemoattractant protein-1) of potential clinical relevance, a body of evidence that this paper aims to review.

A double-blind, randomized study evaluating losartan potassium monotherapy or in combination with hydrochlorothiazide versus placebo in obese patients with hypertension

OBJECTIVES

The objective of this study was to evaluate the effects of losartan +/- hydrochlorothiazide (HCTZ) versus placebo in obese patients with systolic and diastolic hypertension.

RESEARCH DESIGN AND METHODS

Randomized patients (n = 261) were non-diabetic with systolic blood pressure (SBP) > or = 140 and < or = 180 mmHg and diastolic BP (DBP) > or = 95 and < or = 115 mmHg, body mass index > 30 kg/m(2), and waist circumference > 40 (males)/> 35 (females) inches. Patients were randomized to placebo or a forced titration of losartan 50 mg titrated at 4-week intervals to losartan 100 mg, losartan 100 mg/HCTZ 12.5 mg, and losartan 100 mg/HCTZ 25 mg. Primary efficacy measurements were change from baseline in SBP and DBP at 12 weeks. Secondary measurements were change from baseline in BPs at 8 and 16 weeks, percent responders at 12 and 16 weeks, and safety/tolerability. Post-hoc analyses were BP at 4 weeks and achievement of controlled BP (SBP < 140 and/or DBP < 90 mmHg) at 12 and 16 weeks.

RESULTS

Losartan 50 mg reduced BP from 151.6/99.2 mmHg at baseline to 140.1/89.8 mmHg at week 4 (post hoc), 139.5/89.6 mmHg with losartan 100 mg at week 8 (secondary), 134.3/85.9 mmHg with losartan 100 mg/HCTZ 12.5 mg at week 12 (primary), and 132.1/84.9 mmHg with losartan 100 mg/HCTZ 50 mg at week 16 (secondary) (all p < 0.05). Rates of clinical adverse experiences were similar between treatment groups. A limitation of these analyses is the relatively rapid rate of study drug titration, which may not have allowed for the evaluation of the full treatment effect at each titration step.

CONCLUSIONS

We conclude that losartan alone or in combination with HCTZ was generally well tolerated and effective in the treatment of elevated systolic and diastolic BP in obese patients with hypertension.

Reduced plaque formation induced by rosiglitazone in an STZ-diabetes mouse model of atherosclerosis is associated with downregulation of adhesion molecules

Adhesion molecules have been implicated in the development and progression of cardiovascular disease, which is highly prevalent in people with diabetes. Adhesion molecules can mediate adhesion of leukocytes to the endothelium. Furthermore, P-selectin expressed on platelets is able to mediate the adhesion of leukocytes to platelets. In this study, we examine the in-vivo and in-vitro effects of rosiglitazone with particular emphasis on three important adhesion molecules (VCAM-1, ICAM-1 and P-selectin). In the aorta of STZ-diabetic apolipoprotein E-deficient (apoE KO) mice, rosiglitazone significantly reduced both total and arch plaque area. The mechanism for this appeared to be reduced macrophage infiltration into the atherosclerotic plaque which was also associated with reduced mRNA levels for VCAM-1, ICAM-1, MCP-1 and P-selectin in the aorta. In-vitro studies revealed reduced cell adhesion of monocytic cells (THP-1) to fibrinogen and endothelial cells (HUVEC) after incubation with rosiglitazone. Furthermore, the reduction in leukocyte adhesion also correlated with significant reductions in mRNA levels for VCAM-1, ICAM-1 and P-selectin indicating that reduced macrophage infiltration in atherosclerotic plaques may occur as a result of a direct effect of rosiglitazone on adhesion molecules in both monocytes and endothelial cells. Thus, we have shown that rosiglitazone appears to have direct anti-atherosclerotic effects in an animal model of diabetes-associated atherosclerosis which are at least partly due to effects on VCAM-1, ICAM-1, MCP-1 and P-selectin expression which leads to decreased leukocyte adhesion and macrophage infiltration.

Angiotensin-Converting Enzyme Genotype Interacts With Systolic Blood Pressure to Determine Coronary Heart Disease Risk in Healthy Middle-Aged Men

The impact of the ACE I/D polymorphism on coronary heart disease (CHD) risk is modest at most, however it may act as a modifier gene. ACE genotype was determined in 2711 healthy middle-aged men (mean age 56 years) followed for 15 years. No genotype-CHD risk association was found, but when analyzed by quartiles of systolic blood pressure (SBP), compared with II homozygotes, carriage of each additional D allele was protective at lower SBP, but in the highest quartile (SBP >150 mm Hg) conferred almost 1.5 times the risk for CHD (genotype interaction P=0.003). When SBP was analyzed as a continuous variable, again a highly significant association was seen, with the hazard ratio ([95% CI]) for a 1 SD increase in SBP being 0.90 [0.70 to 1.15] for IIs and 1.40 [1.21 to 1.61] for ID/DD (genotype SBP interaction P=0.002). The D allele was protective against CHD at lower SBP but would overtake the II risk at higher SBP. In hypertension, the proinflammatory or prohypertrophic properties of angiotensin II may explain this association. The LPL S447X polymorphism also impacts on CHD risk through interaction with hypertension, and there was an additive action of these 2 polymorphisms and SBP on CHD risk (hazard ratio for 1 SD increase in SBP for combined genotypes 1.78 [1.30 to 2.45]). Thus in the presence of hypertension, common variation in "modifier" genes confers significant CHD risk.

Role of asymmetric dimethylarginine in inflammatory reactions by angiotensin II

Previous investigations have demonstrated that angiotensin (Ang) II induces inflammatory reactions and asymmetric dimethylarginine (ADMA), an endogenous NOS inhibitor, might be a novel inflammatory factor. Endothelial cell activation was induced by incubation with Ang II or ADMA. Incubation with Ang II (10(-6) M) for 24 h elevated the levels of ADMA and decreased the levels of nitrite/nitrate concomitantly with a significant increase in the expression of protein arginine methyltransferase and a decrease in the activity of dimethylarginine dimethylaminohydrolase (DDAH). Exposure to Ang II (10(-6) M for 24 h) also enhanced intracellular ROS elaboration and the levels of tumor necrosis factor (TNF)-alpha and interleukin (IL)-8, upregulated chemokine receptor CXCR2 mRNA expression, increased adhesion of endothelial cells to monocytes and induced a significant increase in the activity of nuclear factor (NF)-kappaB, which was attenuated by pretreatment with the Ang II receptor blocker losartan (1, 3 and 10 muM). Exogenous ADMA (30 microM) also increased ROS generation and the levels of TNF-alpha and IL-8, decreased the levels of nitrite/nitrate, upregulated CXCR2 gene expression, increased endothelial cell binding with monocytes and activated the NF-kappaB pathway, which was inhibited by pretreatment with losartan or L-arginine. These data suggest that ADMA is a potential proinflammatory factor and may be involved in the inflammatory reaction induced by Ang II.

Do valsartan and losartan have the same effects in the treatment of coronary artery disease?

BACKGROUND

Many angiotensin II type 1 receptor blockers (ARBs) are available for clinical use, but because they do not all have the same effects, the present study investigated whether all benefits conferred by ARBs are class effects.

METHODS AND RESULTS

Study 1 was a case-control study of patients with coronary artery disease, which showed that a non-depressor dose of valsartan significantly decreased the rate of target lesion revascularization at 6 months after stenting compared with the control group without ARB treatment. In Study 2, 44 patients with acute myocardial infarction who randomly received an initial lower dose of either valsartan or losartan after stenting were evaluated. The late loss and decrease in %diameter stenosis in the valsartan group were significantly lower than those in the losartan group as assessed by quantitative coronary angiography after 6 months. In addition, the valsartan group showed a significantly lower expression of intracellular adhesion molecule-1 and L-selectin.

CONCLUSION

A non-depressor dose of ARB may have beneficial effects on coronary restenosis that are associated with the regulation of adhesion molecules, and these effects might not be a class effect of ARBs.

Beneficial Effects of Angiotensin II Type 1 Receptor Blocker Antihypertensive Treatment on Inflammation Indices: The Effect of Smoking

The effect of long-term angiotensin II type 1 receptor blocker (ARB) therapy on inflammation indices has not been fully investigated in a hypertensive population. The authors evaluated 323 consecutive nondiabetic patients (mean age, 57 years; 176 men; 92 smokers) with high renin activity and uncomplicated essential hypertension whose blood pressure levels normalized (from 163.9/100.7 mm Hg to 131.6/82.8 mm Hg) after 4 weeks of ARB or ARB/diuretic treatment. All patients underwent full laboratory evaluation (routine examination of blood and urine, liver, kidney, thyroid function, and lipid and glucose profiles), including measurement of high-sensitivity C-reactive protein and serum amyloid A levels, at drug-free baseline, which was repeated after 6 months of ARB or ARB/diuretic treatment. A significant (P<.001) overall decrease was noted in both high-sensitivity C-reactive protein (-0.41+/-1.56 mg/dL) and serum amyloid A (-0.62+/-2.03 mg/dL), but a smaller decrease in high-sensitivity C-reactive protein and serum amyloid A change was seen in the smoker subgroup compared with nonsmokers (P<.05), indicating that the ARB or ARB/diuretic anti-inflammatory effect may be adversely affected by smoking status.

Angiotensin II and inflammation: the effect of angiotensin-converting enzyme inhibition and angiotensin II receptor blockade

Angiotensin II (Ang II) increases adhesion molecules, cytokines and chemokines and exerts a proinflammatory effect on leucocytes, endothelial cells and vascular smooth muscle cells. Acting via the type 1 receptor, Ang II initiates an inflammatory cascade of reduced nicotinamide-adenine dinucleotide phosphate oxidase, reactive oxygen species (ROS) and nuclear factor-kappaB, which mediates transcription and gene expression and increases adhesion molecules and chemokines. An excess of ROS decreases nitric oxide bioavailability, causes endothelial dysfunction, and promotes atherosclerosis. Moreover, Ang II interrupts the anti-inflammatory effects of insulin. Together, these effects promote a prothrombotic state as well as plaque rupture. Ang II receptor blockers suppress mediators of inflammation, including ROS and C-reactive protein, and they increase expression of inhibitory kappaB (an inhibitor of nuclear factor-kappaB). These anti-inflammatory and antioxidative effects, which are probably due in part to unopposed stimulation of the Ang II type 2 receptor, may be beneficial in acute coronary syndromes and may also contribute to the prevention of type II diabetes mellitus, as insulin resistance is mediated by inflammatory processes.

Drugs modulating endothelial function after transplantation

Endothelial cells play a vital role in the success or failure of a transplant procedure. The procedure itself can be viewed as a series of insults that damages the endothelium thereby triggering an inflammatory cascade that may, if uncontrolled, drive the proliferative and fibrotic processes characteristic of chronic graft vasculopathy. Unfortunately, many immunosuppressant agents contribute to this process. Glucocorticoids and the calcineurin inhibitor cyclosporine induce endothelial dysfunction, and although tacrolimus may not have the same disruptive effects on endothelial function as cyclosporine, its endothelial activity is still being established. In contrast, antiproliferative agents slow the proliferation and migration of endothelial cells and so help protect against graft vasculopathy. Researchers agree that endothelial cell dysfunction is a potentially treatable stage in the multifactorial process of graft vasculopathy and rejection. A number of cardiovascular agents (statins, angiotensin converting enzyme inhibitors, calcium channel blockers), immunoregulatory drugs, and dietary compounds have been shown to have beneficial effects on endothelial function. We briefly review the evidence supporting their use as protection for endothelial cells in transplant recipients.

Role of the renin-angiotensin-aldosterone system and proinflammatory mediators in cardiovascular disease

Inflammation is a key mechanism in the initiation, progression, and clinical sequelae of cardiovascular diseases (CVDs), including atherosclerosis, nephropathy, and cardiomyopathy. Angiotensin II, the major effector peptide of the renin-angiotensin-aldosterone system (RAAS), plays a significant role in the advent and perpetuation of these inflammatory diseases, most notably in atherogenesis. Consequently, suppression of the influence of angiotensin II by angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may reduce or potentially reverse atherosclerosis and other inflammation-associated CVDs. Angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors exert anti-inflammatory actions and prevent or reduce the development of atherosclerosis in animal models. Clinically, RAAS suppression reduces common carotid and femoral artery intima-media thickness, thus indicating moderation of the vascular disease process. These clinical benefits likely involve restraint of the deleterious effects of angiotensin II in addition to, or independent of, lowering blood pressure. Increasing evidence that the detection and monitoring of vascular inflammation are important tools in the management of atherosclerosis also implicates the RAAS in this pathogenic process. Inflammatory molecules such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1, tumor necrosis factor-alpha, and C-reactive protein have potential diagnostic and prognostic values in CVD and are modified by angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers. Monitoring these markers may be crucial for determining which agents, or combinations of agents, will result in the most clinically beneficial outcomes for patients. Large-scale trials are still required to determine the effects of the long-term suppression of inflammation on CVDs through the use of RAAS modulating agents, as well as to determine how closely markers of inflammatory activity may correlate with CVD outcomes.

Angiotensin II type 1 receptor expression on human leukocyte subsets: a flow cytometric and RT-PCR study

The renin-angiotensin system plays a key role in the regulation of cardiovascular functions and in particular angiotensin II type 1 receptor (AT1R)-operated pathways are involved in the modulation of inflammation in the vascular wall. In the present study we assessed the pattern of expression of AT1Rs on different human circulating leukocyte subsets. Venous blood was obtained from healthy male subjects. Leukocyte subsets were purified by immunomagnetic cell sorting or identified in whole blood using multiparametric cytometric analysis. RT-PCR analysis showed that AT1R mRNA was expressed in polymorphonuclear leukocytes (PMNs), monocytes, B-lymphocytes, and, to a lesser extent, T-lymphocytes. Flow cytometric analysis revealed that the frequency of expression of AT1Rs was: PMNs>monocytes>or=B-lymphocytes>>T-lymphocytes, while receptor density per positive cells was: PMNs>or=B-lymphocytes>T-lymphocytes>or=monocytes. AT1Rs are expressed on PMNs, monocytes, T- and B-lymphocytes, however the expression pattern is peculiar to each subset, possibly suggesting distinct roles in the various cell types. Investigating the expression and the functional role of AT1Rs on circulating leukocyte subsets, as well as their possible modifications in disease conditions before and after pharmacological treatments, is likely to provide novel clues to the comprehension of the mechanisms involved in the therapeutic efficacy of currently available agents.

Is atrial fibrillation an inflammatory disorder?

There is mounting evidence to support the influence of inflammation in the pathogenesis of atrial fibrillation (AF). Indeed, AF is associated with increased levels of known inflammatory markers, even after adjustment for confounding factors. The renin-angiotensin-aldosterone system (RAAS) appears to play a key role in this process. Atrial biopsies from patients with AF have also confirmed the presence of inflammation. Furthermore, there is preliminary evidence to support a number of drug therapies that have the potential to reduce the clinical burden of AF. In this review, we present an overview of the evidence supporting a link between inflammation and AF, and some of the drug therapies, such as the angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, steroids, fish oils, and vitamin C, that might be efficacious in the prevention of AF by modulating inflammatory pathways.