Vascular inflammation and the renin-angiotensin system

Inhibiting angiotensin-converting enzyme promotes renal repair by modulating progenitor cell activation

Independently of the initial insult, activation and accumulation of parietal progenitor cells within the Bowman's space is a peculiar feature of proliferative chronic kidney diseases. Clinical and experimental studies demonstrated that, in the presence of extensive renal damage, progenitor cells proliferate excessively in the failed attempt to replace the injured podocytes, contributing to the development of crescentic lesions. Inhibiting angiotensin-converting enzyme (ACE) halts crescent formation and promotes the restoration of normal glomerular architecture by limiting progenitor cell proliferation and migration towards the glomerular tuft. Among the mediators involved in the dysregulated response of renal precursors, the angiotensin II (ang II)/ang II type-1 (AT₁) receptor/CXCR4 pathway have been demonstrated to be crucial in proliferative diseases. Understanding the mechanisms underlying the formation of crescentic lesions could be instrumental to developing new therapies, which can be more effective and more targeted to molecular mediators than the currently used cytotoxic agents.

Understanding mechanisms of hypertension in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that predominately affects women of reproductive age. Hypertension is an important cardiovascular risk factor that is prevalent in this patient population. Despite the high incidence of hypertension in women with SLE, the pathophysiological mechanisms underlying the development of hypertension remain poorly understood. This review will focus on disease-related factors, including inflammation, autoantibodies, and sex hormones that may contribute to hypertension in patients with SLE. In addition, we will highlight studies performed by our laboratory using the female NZBWF1 (F1 hybrid of New Zealand Black and New Zealand White strains) mouse model, a spontaneous model of SLE that mimics human disease and develops hypertension and renal injury. Specifically, using female NZBWF1 mice, we have demonstrated that multiple factors contribute to the pathogenesis of hypertension, including the inflammatory cytokine, tumor necrosis factor (TNF)-α, oxidative stress, as well as B-cell hyperactivity and autoantibody production.

Endothelial cell regulation of pulmonary vascular tone, inflammation, and coagulation

The pulmonary endothelium represents a heterogeneous cell monolayer covering the luminal surface of the entire lung vasculature. As such, this cell layer lies at a critical interface between the blood, airways, and lung parenchyma, and must act as a selective barrier between these diverse compartments. Lung endothelial cells are able to produce and secrete mediators, display surface receptor, and cellular adhesion molecules, and metabolize circulating hormones to influence vasomotor tone, both local and systemic inflammation, and coagulation functions. In this review, we will explore the role of the pulmonary endothelium in each of these systems, highlighting key regulatory functions of the pulmonary endothelial cell, as well as novel aspects of the pulmonary endothelium in contrast to the systemic cell type. The interactions between pulmonary endothelial cells and both leukocytes and platelets will be discussed in detail, and wherever possible, elements of endothelial control over physiological and pathophysiological processes will be examined.

Lipopolysaccharide-Induced Spatial Memory and Synaptic Plasticity Impairment Is Preventable by Captopril

Introduction. Renin-angiotensin system has a role in inflammation and also is involved in many brain functions such as learning, memory, and emotion. Neuroimmune factors have been proposed as the contributors to the pathogenesis of memory impairments. In the present study, the effect of captopril on spatial memory and synaptic plasticity impairments induced by lipopolysaccharide (LPS) was investigated. Methods. The rats were divided and treated into control (saline), LPS (1 mg/kg), LPS-captopril (LPS-Capto; 50 mg/kg captopril before LPS), and captopril groups (50 mg/kg) before saline. Morris water maze was done. Long-term potentiation (LTP) from CA1 area of hippocampus was assessed by 100 Hz stimulation in the ipsilateral Schaffer collateral pathway. Results. In the LPS group, the spent time and traveled path to reach the platform were longer than those in the control, while, in the LPS-Capto group, they were shorter than those in the LPS group. Moreover, the slope and amplitude of field excitatory postsynaptic potential (fEPSP) decreased in the LPS group, as compared to the control group, whereas, in the LPS-Capto group, they increased compared to the LPS group. Conclusion. The results of the present study showed that captopril improved the LPS-induced memory and LTP impairments induced by LPS in rats. Further investigations are required in order to better understand the exact responsible mechanism(s).

Perirenal Edema as a potential hint towards primary hypertension—Preliminary findings in MRI breast cancer staging

Purpose

To demonstrate our primary findings, indicating perirenal edema as a first imaging sign towards primary hypertension.

Methods

Out of 3190 consecutive MR-Mammography (MRM) examinations, 777 were performed with an additional body array coil. Incidentally, “perirenal edema” could be linked to a patient history of hypertension. We Therefore specifically further observed the correlation.

Results

Of 777 patients 86 (11%) patients showed the perirenal edema sign (PES). Upon inquiry all of these cases (100%) confirmed a past or present history of hypertensive disease (i.e. blood pressure above 140/90 and/or anti-hypertensive treatment).

Conclusion

Our preliminary results strongly indicate a strong correlation between perirenal edema and primary hypertension.

Relationship of Genetic Polymorphisms of Aldosterone Synthase Gene Cytochrome P450 11B2 and Mineralocorticoid Receptors with Coronary Artery Disease in Taiwan

The aldosterone synthase gene, cytochrome P450 11B2 (CYP11B2), and mineralocorticoid receptor (MR) genes have been reported to be associated with coronary artery disease (CAD). In this study, we investigated the association of single nucleotide polymorphisms (SNPs) of CYP11B2 (CYP11B2 T-344C) and MR (MR C3514G and MR C4582A) with CAD in Taiwanese. Six hundred and nine unrelated male and female subjects who received elective coronary angiography were recruited from Chung Shan Medical University Hospital. The enrolled subjects were those who had a positive noninvasive test. CYP11B2 T-344C, MR C3514G and MR C4582A were determined by polymerase chain reaction-restriction fragment length polymorphism. We found that women with CYP11B2 C/C had a higher risk of developing CAD. However, there were no significant differences in the genotype distributions of MR C3514G and MR C4582A between the women with and without CAD. In multivariate analysis, CYP11B2 T-344C was most significantly associated with CAD in Taiwanese women. In conclusions, CYP11B2 C/C was more significantly associated with the development of CAD than diabetes mellitus or hypertension. This implies that CYP11B2 C/C plays a more important role than some conventional risk factors in the development of CAD in Taiwanese women.

Irbesartan attenuates atherosclerosis in Watanabe heritable hyperlipidemic rabbits: noninvasive imaging of inflammation by 18F-fluorodeoxyglucose positron emission tomography

The purpose of this study was to assess the usefulness of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in evaluating the antiatherogenic effects of irbesartan, an angiotensin II type 1 receptor blocker. Watanabe heritable hyperlipidemic rabbits were divided into the irbesartan-treated group (75 mg/kg/d; n  =  14) and the control group (n  =  14). After a 9-month treatment, rabbits underwent 18F-FDG PET. Using the aortic lesions, autoradiography and histologic examinations were performed. PET imaging clearly visualized the thoracic lesions of control rabbits and showed a significant decrease in the 18F-FDG uptake level of irbesartan-treated rabbits (78.8% of controls; p < .05). Irbesartan treatment significantly reduced the plaque size (43.1% of controls) and intraplaque macrophage infiltration level (48.1% of controls). The 18F-FDG uptake level in plaques positively correlated with the plaque size (r  =  .65, p < .05) and macrophage infiltration level (r  =  .57, p < .05). Noninvasive imaging by 18F-FDG PET is useful for evaluating the therapeutic effects of irbesartan and reflects inflammation, a key factor involved in the therapeutic effects.

Angiotensin III increases monocyte chemoattractant protein-1 expression in cultured human proximal tubular epithelial cells

BACKGROUND/AIMS

We investigated whether angiotensin III (Ang III) is involved in monocyte recruitment through regulation of the chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured human proximal tubular epithelial cells (HK-2 cells).

METHODS

We measured MCP-1 levels in HK-2 cells that had been treated with various concentrations of Ang III and Ang II type-1 (AT1) receptor antagonists at various time points. The phosphorylation states of p38, c-Jun N-terminal kinases (JNK), and extracellular-signal-regulated kinases were measured in Ang III-treated cells to explore the mitogen-activated protein kinase (MAPK) pathway. MCP-1 levels in HK-2 cell-conditioned media were measured after pre-treatment with the transcription factor inhibitors curcumin or pyrrolidine dithiocarbamate.

RESULTS

Ang III increased MCP-1 protein production in dose- and time-dependent manners in HK-2 cells, which was inhibited by the AT1 receptor blocker losartan. p38 MAPK activity increased significantly in HK-2 cells exposed to Ang III for 30 minutes, and was sustained at higher levels after 60 minutes (p < 0.05). Total phosphorylated JNK protein levels tended to increase 20 minutes after stimulation with Ang III. Pre-treatment with a p38 inhibitor, a JNK inhibitor, or curcumin significantly inhibited Ang III-induced MCP-1 production.

CONCLUSIONS

Ang III increases MCP-1 synthesis via stimulation of intracellular p38 and JNK MAPK signaling activity and subsequent activated protein-1 transcriptional activity in HK-2 cells.

Long Noncoding RNAs in Atherosclerosis

Long noncoding RNAs (lncRNAs) were a group of non-protein-coding RNAs ＞200 nucleotides and participated in biological processes and pathophysiological conditions in vivo or in vitro. Recently, more and more lncRNAs interfering with the progress of atherosclerosis were identified and characterized in the atherogenic cells such as vascular smooth muscle cells (VSMCs), endothelial cells (ECs), and monocytes/macrophages showing that lncRNAs play an important role in the occurrence of atherosclerosis. In this review, we summarized and highlighted the lncRNAs that play a role in the process of atherosclerosis. This study may provide helpful insights regarding further study of lncRNAs associated with atherosclerosis.

Critical Roles of Reactive Oxygen Species in Age-Related Impairment in Ischemia-Induced Neovascularization by Regulating Stem and Progenitor Cell Function

Reactive oxygen species (ROS) regulate bone marrow microenvironment for stem and progenitor cells functions including self-renewal, differentiation, and cell senescence. In response to ischemia, ROS also play a critical role in mediating the mobilization of endothelial progenitor cells (EPCs) from the bone marrow to the sites of ischemic injury, which contributes to postnatal neovascularization. Aging is an unavoidable biological deteriorative process with a progressive decline in physiological functions. It is associated with increased oxidative stress and impaired ischemia-induced neovascularization. This review discusses the roles of ROS in regulating stem and progenitor cell function, highlighting the impact of unbalanced ROS levels on EPC dysfunction and the association with age-related impairment in ischemia-induced neovascularization. Furthermore, it discusses strategies that modulate the oxidative levels of stem and progenitor cells to enhance the therapeutic potential for elderly patients with cardiovascular disease.

Effect of lipopolysaccharide on angiotensin II type 1 receptor expression and function in human pulmonary microvascular endothelial cells

Lipopolysaccharides (LPSs) are an important initiation factor in acute respiratory distress syndrome. The aim of the present study was to investigate the effect of LPSs on the regulation of angiotensin II (Ang II) receptors in human pulmonary microvascular endothelial cells (HPMECs). HPMECs were treated with 0, 50, 100 or 200 ng/ml LPS and incubated for 4, 8, 12 or 16 h. The expression of Ang II type 1 receptor (AT1R) and Ang II type 2 receptor (AT2R) was determined using reverse transcription‑polymerase chain reaction and western blot analysis. The affinity to Ang II was measured using a radioligand binding assay. No AT2R expression was detected with or without LPS administration in HPMECs, and LPS treatment increased the expression level of AT1R. A time‑dependent increase of AT1R transcription was observed in the 50 ng/ml group, while in the 100 and 200 ng/ml groups, the AT1R mRNA levels reached peak values at 4 h and remained unchanged. The protein level of AT1R increased significantly in a dose‑dependent manner for each incubation time period. A time‑dependent increase in the protein level was observed in the 50 and 100 ng/ml groups. As for the 200 ng/ml group, the level of AT1R reached a peak value at 8 h. Maximal binding (Bmax) significantly increased following LPS treatment and Bmax of the 50 ng/ml group exhibited a time‑dependent increase. The Bmax of the 100 and 200 ng/ml groups reached peak values at 12 and 8 h, respectively, and decreased thereafter. The dissociation constant remained unchanged following LPS treatment. Thus, treatment with LPS increased AT1R expression and its Bmax to Ang II in HPMECs, however, did not alter the affinity of AT1R to Ang II.

Influence of Renal Sympathetic Denervation on Cardiac Extracellular Matrix Turnover and Cardiac Fibrosis

BACKGROUND

Renal sympathetic denervation (RSD) represents an effective treatment option for patients with resistant arterial hypertension (HT). Extracellular matrix (ECM) turnover and deposition are essential processes in HT-related cardiovascular remodeling, fibrosis, and cardiac hypertrophy and contribute to hypertensive heart disease.

OBJECTIVES

The primary aim of the present study was to examine the effect of RSD on increased collagen turnover as reflected by serum levels of amino-terminal pro-peptides (PINP, PIIINP) and a carboxyl-terminal pro-peptide (PICP), specific biomarkers for cardiac ECM turnover and cardiovascular fibrosis.

METHODS

A total of 100 consecutive patients (mean age: 65.9±10.1 years) undergoing RSD were included in this study. A therapeutic response was defined as an office systolic blood pressure (SBP) reduction of >10mm Hg 6 months after RSD. Venous serum samples for measurement of PICP, PINP, and PIIINP were collected prior to and 6 months after RSD.

RESULTS

A significant reduction in the office SBP of 24.3 mm Hg (SBP baseline: 166.9±14.3 mm Hg (P < 0.001) was documented 6 months after RSD. At this time point, the serum levels of PICP, PINP, and PIIINP (P < 0.01) were significantly decreased compared to baseline values in patients with an increased collagen turnover, showing significant differences comparing BP responders and nonresponders.

CONCLUSION

In addition to the effective blood pressure reduction in response to RSD, this study demonstrates a positive effect of RSD on biomarkers reflecting cardiovascular ECM turnover and deposition. These results suggest a beneficial effect of RSD on cardiovascular fibrosis, hypertensive heart disease, and end-organ damage in high-risk patients.

Apolipoprotein-J prevents angiotensin II-induced apoptosis in neonatal rat ventricular cells

Background

Up-regulation of angiotensin II (AngII) occurs in cardiac diseases, such as congestive heart failure, cardiac hypertrophy, myocardial ischemia and atrial fibrillation, which represent major health problems. Evidence from in vivo studies suggests that the level of Apolipoprotein-J (ApoJ) is also elevated but plays a protective role in cardiovascular disease. This study aimed to evaluate the protective effects of ApoJ against cytotoxicity of AngII in neonatal rat ventricular cells (NRVCs).

Methods and results

In culture, NRVCs were damaged by exposure to AngII, and ApoJ overexpression using an adenovirus vector significantly reduced the AngII-induced cell injury. ApoJ also prevented AngII from augmenting Nox2/gp91^phox expression. The reactive oxygen species (ROS) scavenger, Mn(III)TBAP, showed similar results of attenuating AngII-induced cell damage. Furthermore, ApoJ overexpression increased phosphorylation of Akt, and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 diminished the antioxidant effects of ApoJ, and prevented the protective effect of ApoJ against the cytotoxicity of AngII. Moreover, upregulation of nuclear factor κB (NF-κB) p65 expression and phosphorylation of p38 mitogen-activated protein kinase (MAPK) mediated by AngII in cultured NRVCs were significantly inhibited by overexpression of ApoJ. The p38 MAPK inhibitor SB203580 and the NF-κB inhibitor PDTC protected NRVCs from injury caused by AngII.

Conclusions

ApoJ serves as a cytoprotective protein in NRVCs against cytotoxicity of AngII through the PI3K-Akt-ROS and MAPK/ NF-κB pathways.

Vascular and plaque imaging with ultrasmall superparamagnetic particles of iron oxide

Cardiovascular Magnetic Resonance (CMR) has become a primary tool for non-invasive assessment of cardiovascular anatomy, pathology and function. Existing contrast agents have been utilised for the identification of infarction, fibrosis, perfusion deficits and for angiography. Novel ultrasmall superparamagnetic particles of iron oxide (USPIO) contrast agents that are taken up by inflammatory cells can detect cellular inflammation non-invasively using CMR, potentially aiding the diagnosis of inflammatory medical conditions, guiding their treatment and giving insight into their pathophysiology. In this review we describe the utilization of USPIO as a novel contrast agent in vascular disease.

The Sirt1 activator SRT1720 attenuates angiotensin II-induced atherosclerosis in apoE⁻/⁻ mice through inhibiting vascular inflammatory response

Activation of the silent mating type information regulation 2 homolog 1 (SIRT1) has been shown consistent antiinflammatory function. However, little information is available on the function of SIRT1 during Angiotensin II (AngII)-induced atherosclerosis. Here we report atheroprotective effects of sirt1 activation in a model of AngII-accelerated atherosclerosis, characterized by suppression pro-inflammatory transcription factors Nuclear transcription factor (NF)-κB and Signal Transducers and Activators of Transcription. (STAT) signaling pathway, and atherosclerotic lesion macrophage content. In this model, administration of the SIRT1 agonist SRT1720 substantially attenuated AngII-accelerated atherosclerosis with decreasing blood pressure and inhibited NF-κB and STAT3 activation, which was associated with suppression of inflammatory factor and atherogenic gene expression in the artery. In vitro studies demonstrated similar changes in AngII-treated VSMCs and macrophages: SIRT1 activation inhibited the expression levels of proinflammatory factor. These studies uncover crucial proinflammatory mechanisms of AngII and highlight actions of SIRT1 activation to inhibit AngII signaling, which is atheroprotective.

Inflammation in venous thromboembolism: Cause or consequence?

Venous thromboembolism (VTE) which includes deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE) is a moderately common disease especially in elderly population with high rate of recurrence and complications. Evidence is accumulating that VTE is not restricted to coagulation system and immune system appears to be involved in formation and resolution of thrombus. The present study was aimed at reviewing current evidences on immune system abnormalities such as alterations in cytokines, chemokines and immune cells. Also, current evidences suggest that; a, inflammation in general functions as a double-edged sword, b, inflammation can be both a cause and a consequence of VTE, and c, current anti-coagulation therapies are not well-equipped with the capacity to selectively inhibit inflammatory cells and pathways. Applying such inferences for selective pharmacological targeting of immune mediators in VTE and thereby for adoption of higher effective anti-thromboinflammatory strategies, either therapeutic or prophylactic, is henceforth to be considered as the line of research for future.

Compound 21, a selective angiotensin II type 2 receptor agonist, downregulates lipopolysaccharide-stimulated tissue factor expression in human peripheral blood mononuclear cells

Intricate interrelationships connect tissue factor (TF), the principal initiator of the clotting cascade, to inflammation, a cross-talk amplified by locally active angiotensin II, a proinflammatory agent with direct TF-stimulating properties mediated by the angiotensin II type 1 receptor (AT1R)s. However, angiotensin II also stimulates angiotensin II type 2 receptor (AT2R)s and they may as well contribute to TF expression, a possibility in need of further evaluation. We investigated the effect of C21, a highly specific AT2R agonist, on TF antigen (ELISA), procoagulant activity (PCA, one-stage clotting assay) and TF-mRNA (real-time PCR) in peripheral blood mononuclear cell (PBMC)s activated by lipopolysaccharide (LPS), a pro-inflammatory and procoagulant stimulus. C21 downregulated LPS-stimulated TF antigen, PCA and TF mRNA, an effect abolished by PD123 319, a selective AT2R antagonist, and left unchanged by omesartan, a selective AT1R antagonist. PD123 319 per se did not affect LPS-induced TF expression while omesartan inhibited and BAY 11-7082, a specific NFκB inhibitor, abolished endotoxin-activated procoagulant activity (PCA). C21, a selective AT2R agonist, downregulates the transcriptional expression of TF in LPS-activated PBMCs, a finding consistent with the existence in PBMCs of AT2Rs whose stimulation attenuates inflammation-mediated procoagulant responses. The data open insofar unexplored and potentially relevant facets to our understanding of the complex links connecting angiotensin II to inflammation and coagulation.

Acute and subchronic exposure to air particulate matter induces expression of angiotensin and bradykinin-related genes in the lungs and heart: Angiotensin-II type-I receptor as a molecular target of particulate matter exposure

Background

Particulate matter (PM) adverse effects on health include lung and heart damage. The renin-angiotensin-aldosterone (RAAS) and kallikrein-kinin (KKS) endocrine systems are involved in the pathophysiology of cardiovascular diseases and have been found to impact lung diseases. The aim of the present study was to evaluate whether PM exposure regulates elements of RAAS and KKS.

Methods

Sprague–Dawley rats were acutely (3 days) and subchronically (8 weeks) exposed to coarse (CP), fine (FP) or ultrafine (UFP) particulates using a particulate concentrator, and a control group exposed to filtered air (FA). We evaluated the mRNA of the RAAS components At1, At2r and Ace, and of the KKS components B1r, B2r and Klk-1 by RT-PCR in the lungs and heart. The ACE and AT₁R protein were evaluated by Western blot, as were HO-1 and γGCSc as indicators of the antioxidant response and IL-6 levels as an inflammation marker.

We performed a binding assay to determinate AT₁R density in the lung, also the subcellular AT₁R distribution in the lungs was evaluated. Finally, we performed a histological analysis of intramyocardial coronary arteries and the expression of markers of heart gene reprogramming (Acta1 and Col3a1).

Results

The PM fractions induced the expression of RAAS and KKS elements in the lungs and heart in a time-dependent manner. CP exposure induced Ace mRNA expression and regulated its protein in the lungs. Acute and subchronic exposure to FP and UFP induced the expression of At1r in the lungs and heart. All PM fractions increased the AT₁R protein in a size-dependent manner in the lungs and heart after subchronic exposure. The AT₁R lung protein showed a time-dependent change in subcellular distribution. In addition, the presence of AT₁R in the heart was accompanied by a decrease in HO-1, which was concomitant with the induction of Acta1 and Col3a1 and the increment of IL-6. Moreover, exposure to all PM fractions increased coronary artery wall thickness.

Conclusion

We demonstrate that exposure to PM induces the expression of RAAS and KKS elements, including AT₁R, which was the main target in the lungs and the heart.

Haemostatic and inflammatory alterations in familial hypercholesterolaemia, and the impact of angiotensin II infusion

INTRODUCTION

We examined potential prothrombotic and proinflammatory effects of angiotensin II in 16 otherwise healthy familial hypercholesterolaemia subjects and 16 matched controls.

METHODS

Markers of fibrinolysis, thrombin generation and inflammation were assessed in plasma before, during and 1h after a 3h intravenous infusion of angiotensin II. In addition, placebo experiments with saline infusion were carried out.

RESULTS

Baseline plasminogen activator inhibitor type-1 activity and plasmin-antiplasmin-complex concentrations were similar in FH and controls, as were interleukin-6, leukocyte counts and C-reactive protein. Fibrinogen levels were higher in FH, and we observed a greater thrombin generating potential in FH (calibrated automated thrombogram), but no signs of elevated thrombin generation in vivo (prothrombin fragment 1+2). During angiotensin infusion plasminogen activator inhibitor type-1 activity decreased and plasmin-antiplasmin-complex concentrations increased similarly in FH and controls. Total and maximal amount of thrombin generated was unchanged, as were prothrombin-fragment-1+2 levels. Interleukin-6 and leukocyte counts increased similarly in both groups during angiotensin infusion, while fibrinogen tended to increase in FH and increased in controls. During saline infusion plasminogen activator inhibitor type-1 activity and prothrombin fragment 1+2 concentrations fell, whereas other markers were unchanged.

CONCLUSIONS

FH exhibits an increased thrombin generation potential, an intact fibrinolysis, and has no convincing signs of inflammation. Angiotensin has proinflammatory effects, and might have minor profibrinolytic and procoagulatory effects.

Perspectives for angiotensin profiling with liquid chromatography/mass spectrometry to evaluate ACE/ACE2 balance in endothelial dysfunction and vascular pathologies

Vascular injury, characterized by endothelial dysfunction, inflammation, structural remodeling, thrombosis and calcification leads to cardiovascular diseases. Angiotensin (Ang) II (1-8) - synthesized mainly by angiotensin converting enzyme (ACE) is the best characterized mediator of the renin-angiotensin system (RAS). This peptide initially identified by its vasoactive properties was found to play a major role in vascular response to insult. However, recent discovery of angiotensin converting enzyme 2 (ACE2) that produces vasoprotective Ang-(1-7) peptide highlighted complexity of the system and suggested that balance between ACE/Ang II and ACE2/Ang-(1-7) is fundamental in maintaining vascular homeostasis and its disorders are associated with cardiovascular pathology. There is therefore a need to develop methods for comprehensive analysis of biologically active Ang peptides and their metabolites of ACE/Ang II and ACE2/Ang-(1-7) axes. Liquid chromatography/mass spectrometry (LC/MS) is an analytical technique that offers potential for specific, simultaneous analysis of Ang peptides. With sensitivity added by application of preconcentration nanochromatography reaching picomolar concentrations, practically all Ang peptides identified so far could be quantified in biological samples. Ang profiling is important not only for understanding their physiological or pathological role but could also serve as an early diagnostic biomarker of endothelial dysfunction and cardiovascular pathology. It could also be used for monitoring the efficacy of the RAS-targeted therapies. Although, the methodology requires further improvements to adopt it for routine application, Ang peptide profiling with targeted LC/MS analysis might assess functional balance between ACE/Ang II and ACE2/Ang-(1-7) axes, facilitate our understanding of the cardiovascular pathology and enhance biomarker portfolio in cardiovascular diseases.

RNA interference of myocyte enhancer factor 2A accelerates atherosclerosis in apolipoprotein E-deficient mice

Objective

Myocyte enhancer factor-2A (MEF 2A) has been shown to be involved in atherosclerotic lesion development, but its role in preexisting lesions is still unclear. In the present study we aim to assess the role of MEF 2A in the progression of pre-existing atherosclerosis.

Methods

Eighty apolipoprotein E-deficient mice (APOE KO) were randomly allocated to control, scramble and MEF 2A RNA interference (RNAi) groups, and constrictive collars were used to induce plaque formation. Six weeks after surgery, lentiviral shRNA construct was used to silence the expression of MEF 2A. Carotid plaques were harvested for analysis 4 weeks after viral vector transduction. Inflammatory gene expression in the plasma and carotid plaques was determined by using ELISAs and real-time RT-PCR.

Results

The expression level of MEF 2A was significantly reduced in plasma and plaque in the RNAi group, compared to the control and NC groups, whereas the expression level of pro-inflammatory cytokines was markedly increased. Silencing MEF 2A using lentiviral shRNA significantly reduced the plaque collagen content and fibrous cap thickness, as well as increased plaque area. However, silencing MEF 2A had no obvious effect on plaque lipid content.

Conclusions

Lentivirus-mediated MEF 2A shRNA accelerates inflammation and atherosclerosis in APOE KO mice, but has no effect on lipoprotein levels in plasma.

Functional Long Non-coding RNAs in Vascular Smooth Muscle Cells

Increasing evidence shows that long non-coding RNAs (lncRNAs) are not "transcriptional noise" but function in a myriad of biological processes. As such, this rapidly growing class of RNAs is important in both development and disease. Vascular smooth muscle cells are integral cells of the blood vessel wall. They are responsible for relaxation and contraction of the blood vessel and respond to hemodynamic as well as environmental signals to regulate blood pressure. Pathophysiological changes to these cells such as hyperproliferation, hypertrophy, migration, and inflammation contribute to cardiovascular diseases (CVDs) such as restenosis, hypertension, and atherosclerosis. Understanding the molecular mechanisms involved in these pathophysiological changes to VSMCs is paramount to developing therapeutic treatments for various cardiovascular disorders. Recent studies have shown that lncRNAs are key players in the regulation of VSMC functions and phenotype and, perhaps also, in the development of VSMC-related diseases. This chapter describes our current understanding of the functions of lncRNAs in VSMCs. It highlights the emerging role of lncRNAs in VSMC proliferation and apoptosis, their role in contractile and migratory phenotype of VSMCs, and their potential role in VSMC disease states.

Methylation of promoter regions of genes of the human intrauterine Renin Angiotensin system and their expression

The intrauterine renin angiotensin system (RAS) is implicated in placentation and labour onset. Here we investigate whether promoter methylation of RAS genes changes with gestation or labour and if it affects gene expression. Early gestation amnion and placenta were studied, as were term amnion, decidua, and placenta collected before labour (at elective caesarean section) or after spontaneous labour and delivery. The expression and degree of methylation of the prorenin receptor (ATP6AP2), angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AGTR1), and two proteases that can activate prorenin (kallikrein, KLK1, and cathepsin D, CTSD) were measured by qPCR and a DNA methylation array. There was no effect of gestation or labour on the methylation of RAS genes and CTSD. Amnion and decidua displayed strong correlations between the percent hypermethylation of RAS genes and CTSD, suggestive of global methylation. There were no correlations between the degree of methylation and mRNA abundance of any genes studied. KLK1 was the most methylated gene and the proportion of hypermethylated KLK1 alleles was lower in placenta than decidua. The presence of intermediate methylated alleles of KLK1 in early gestation placenta and in amnion after labour suggests that KLK1 methylation is uniquely dynamic in these tissues.

Occurrence of the JAK2 V617F mutation in patients with peripheral arterial disease

The acquired JAK2 V617F mutation is common in patients with myeloproliferative neoplasms. We previously showed that JAK2 V617F is also found in coronary patients, most of them affected by coronary atherosclerosis. Peripheral arterial disease (PAD) is another important manifestation of atherosclerosis. However, prevalence of the JAK2 V617F mutation and its effect on clinical or hematologic characteristics is unknown in PAD patients. In the present study we determined the prevalence of JAK2 V617F in a cohort of 287 patients with sonographically proven PAD and compared mutation frequency with mutational status of 997 healthy people from the KORA F4 study. JAK2 V617F screening and quantification of allele burden in both cohorts was performed with same allele-specific quantitative real-time PCR method. From a total of 287 PAD patients, 9 individuals were tested positive for the JAK2 V617F mutation. One patient showed elevated hemoglobin values, indicating polycythemia vera. Observed JAK2 V617F frequency (3.1%) in PAD patients showed a 5-fold, highly significant increase compared with healthy people (P < 0.001). Furthermore, occurrence of the mutation in PAD patients was significantly decreased in patients using aspirin (P = 0.003). We conclude that the prevalence of JAK2 V617F mutation is significantly increased in PAD patients compared to the general population. Future studies are warranted to confirm our observations and to define the underlying mechanisms behind our findings.

A functional (pro)renin receptor is expressed in human lymphocytes and monocytes

The renin-angiotensin system (RAS) is involved in inflammation. The signaling via the ANG II type 1 receptor in human lymphocytes and monocytes, which play key roles in pathophysiology of glomerulonephritis (GN), can enhance inflammation. However, the role of the (pro)renin receptor [(P)RR], a component of the RAS, in inflammatory reactions is unknown. We assessed whether (P)RR is expressed in human lymphocytes and monocytes by RT-PCR, Western blotting, flow cytometry, and immunohistochemistry, and whether (P)RR functions in inflammation. (P)RR mRNA and protein were expressed in human peripheral blood mononuclear cells (PBMCs). Flow cytometric analysis revealed high expression of (P)RR on monocytes. (P)RR was present on PBMCs, infiltrating lymphocytes, and macrophages around glomeruli with a crescent in anti-neutrophil cytoplasmic antibody (ANCA)-associated GN. Renin stimulation of PBMCs from healthy subjects in the presence of the ANG II type 1 receptor and ANG II type 2 receptor blockers induced ERK1/2 phosphorylation and release of IL-6 and expression of cyclooxygenase-2 (COX-2). The increases in cytokine release and COX-2 expression were inhibited in the presence of an ERK1/2 inhibitor. (P)RR knockdown by small interfering RNA in U937 cells, a human leukemic monocyte lymphoma cell line, significantly decreased ERK1/2 phosphorylation after renin stimulation. Thus (P)RR expressed in human inflammatory cells might contribute to inflammation in ANCA-associated GN.

Beneficial effects of renal sympathetic denervation on cardiovascular inflammation and remodeling in essential hypertension

BACKGROUND

Renal sympathetic denervation (RSD) represents a potential treatment option for certain patients with resistant arterial hypertension (HT). HT is associated with chronic vascular inflammation and remodeling, contributing to progressive vascular damage, and atherosclerosis. The present study aimed to evaluate the influence of RSD on cardiovascular inflammation and remodeling by determining serum levels of interleukin-6 (IL-6), high-sensitive C-reactive protein (hsCRP), matrix metalloproteinases (MMP), and tissue inhibitor of metalloproteinases (TIMP).

METHODS

A total of 60 consecutive patients (age 67.9 ± 9.6 years) undergoing RSD were included. A therapeutic response was defined as an office systolic blood pressure (SBP) reduction of >10 mmHg 6 months after RSD. Venous serum samples for measurement of hsCRP, IL-6, MMP-2, MMP-9, and TIMP-1 were collected prior to and 6 months after RSD.

RESULTS

A significant reduction in office SBP of 26.4 mmHg [SBPbaseline 169.3 mmHg (SD 11.3), p < 0.001] was documented 6 months after RSD. The serum levels of hsCRP (p < 0.001) and the pro-inflammatory cytokine IL-6 (p < 0.001) were significantly decreased compared to baseline values. The levels of MMP-9 (p = 0.024) and MMP-2 (p < 0.01) were significantly increased compared to baseline values.

CONCLUSION

In addition to the effective blood pressure reduction in response to RSD, this study demonstrates a positive effect of RSD on biomarkers reflecting vascular inflammation and remodeling. These results suggest a possible prognostic benefit of RSD in high-risk patients for endothelial dysfunction and cardiovascular remodeling as well as end-organ damage.

Role of ACE I/D gene polymorphisms on the effect of ramipril in inflammatory response and myocardial injury in patients undergoing coronary artery bypass grafts

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors block angiotensin II formation and release bradykinin, which is effective in the regulation of oxidoinflammatory injury. Some reports denote alterations in the effectiveness of ACE inhibitors in association with ACE insertion/deletion (I/D) gene polymorphisms. This study investigates the effects of ramipril on the oxidoinflammatory cytokines (IL-6, IL-8, TNF-alpha) and TnT (myocardial injury marker) and their alteration in association with ACE I/D gene polymorphisms.

METHODS

The study group (n = 51) patients received ramipril before coronary artery bypass grafting (CABG), while patients not receiving ramipril (n = 51) constituted the controls. TNFα, IL-6, and IL-8 were evaluated using ELISA and TnT by electrochemiluminescence methods before the induction of anesthesia (t1), at the 20th minute following cross-clamping (t2), at the end of the operation (t3), and at the 24th hour from the commencement of anesthesia (t4). Genotyping was performed by PCR.

RESULTS

Differences between the groups were significant at t4 for the TNFα and at t3 for IL-6 (p < 0.05). The TnT levels increased from t2 onward in the control group and were highest in t3. Changes in t3 and t4 values in both groups according to their t1 values were significant (p < 0.05). However, differences between the groups were insignificant (p > 0.05). The IL-6, IL-8, TNFα, and TnT serum levels had no correlation with the ACE I/D gene polymorphism.

CONCLUSION

Low cytokine and TnT levels in the study group, especially after cross-clamping, may indicate the protective effect of ramipril from oxidoinflammatory injury. This effect did not appear to be associated with the ACE I/D gene polymorphism.

In prehypertension leukocytosis is associated with body mass index but not with blood pressure or incident hypertension

BACKGROUND

Previous studies reported increased white blood cell counts (WBCCs), an inflammatory marker, in hypertension, prehypertension and metabolic syndrome. Evidence suggests that inflammation precedes blood pressure (BP) elevation and may contribute to incident hypertension. Angiotensin receptor blockers (ARBs) may reduce inflammation. We analyzed WBCC trends in TRial Of Preventing HYpertension (TROPHY) to determine if this inflammatory marker predicted incident hypertension in prehypertensive individuals and whether randomized assignment to the ARB candesartan (391 individuals) for 2 years, lowered WBCC compared with placebo-treated controls (381 individuals).

METHODS

A new analysis of TROPHY trial data.

RESULTS

In the total population, baseline BMI correlated with WBCC (r = 0.185, P < 0.0001), neutrophils (r = 0.135, P < 0.001) and lymphocytes (r = 0.204, P < 0.0001). Baseline triglycerides also correlated significantly with inflammatory markers. Despite a wide range of home BP (HBP) values, HBP did not correlate with baseline WBCC counts. After 2 years, candesartan decreased placebo corrected HBP by -5.5/-2.5 mmHg, (P < 0.0001), but WBCC, neutrophil and lymphocyte counts were not different in placebo and in candesartan groups. Baseline WBCC, neutrophils and lymphocyte counts did not predict incident hypertension in the placebo group.

CONCLUSION

In TROPHY, candesartan lowered BP but did not alter WBCC. Baseline WBCC did not predict incident hypertension. Our findings do not support the hypothesis that inflammation contributes to incident hypertension or that ARB treatment suppresses inflammation. The significant independent association of WBCC with baseline BMI and triglycerides is consistent with the evidence that obesity and insulin resistance are associated with inflammation. The findings highlight the importance of effective lifestyle modification in prehypertension to reduce inflammatory cardio-metabolic risk and suppress transition to hypertension.

Angiotensin II upregulates endothelial lipase expression via the NF-kappa B and MAPK signaling pathways

BACKGROUND

Angiotensin II (AngII) participates in endothelial damage and inflammation, and accelerates atherosclerosis. Endothelial lipase (EL) is involved in the metabolism and clearance of high density lipoproteins (HDL), the serum levels of which correlate negatively with the onset of cardiovascular diseases including atherosclerosis. However, the relationship between AngII and EL is not yet fully understood. In this study, we investigated the effects of AngII on the expression of EL and the signaling pathways that mediate its effects in human umbilical vein endothelial cells (HUVECs).

METHODS AND FINDINGS

HUVECs were cultured in vitro with different treatments as follows: 1) The control group without any treatment; 2) AngII treatment for 0 h, 4 h, 8 h, 12 h and 24 h; 3) NF-κB activation inhibitor pyrrolidine dithiocarbamate (PDTC) pretreatment for 1 h before AngII treatment; and 4) mitogen-activated protein kinase (MAPK) p38 inhibitor (SB203580) pretreatment for 1 h before AngII treatment. EL levels in each group were detected by immunocytochemical staining and western blotting. HUVECs proliferation was detected by MTT and proliferating cell nuclear antigen (PCNA) immunofluorescence staining. NF-kappa B (NF-κB) p65, MAPK p38, c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and phosphorylated extracellular signal-regulated kinase (p-ERK) expression levels were assayed by western blotting. The results showed that the protein levels of EL, NF-κB p65, MAPK p38, JNK, and p-ERK protein levels, in addition to the proliferation of HUVECs, were increased by AngII. Both the NF-kB inhibitor (PDTC) and the MAPK p38 inhibitor (SB203580) partially inhibited the effects of AngII on EL expression.

CONCLUSION

AngII may upregulate EL protein expression via the NF-κB and MAPK signaling pathways.

Adiponectin ameliorates angiotensin II-induced vascular endothelial damage

Adiponectin is an adipocyte-specific adipocytokine that possesses anti-atherogenic and anti-diabetic properties. It has been shown to have a beneficial effect on the cardiovascular system, but it remains to be elucidated whether adiponectin has a therapeutic effect on vascular damage induced by the potential vasoactive substance angiotensin II (Ang II). In this study, the effects of adiponectin on Ang II-induced vascular endothelial damage were investigated. In cultured human umbilical vein endothelium cells, Ang II stimulation increased generation of ROS and 4-hydroxy-2-nonenal, both of which were clearly restored by administration of adiponectin. In addition, administration of adiponectin was found to increase cell viability and prevent apoptosis. Our results also demonstrate that the protective effects of adiponectin against Ang II-induced vascular endothelial damage are dependent on the binding of adiponectin to its cell surface receptor 1. Importantly, we found that adiponectin treatment modulates the apoptotic pathway by reducing the expression of LOX-1, up-regulating both cIAP-1 and the ratio of Bcl-2/Bax. Finally, our data displayed that the protective effects of adiponectin against Ang II cytotoxicity depend on AMPK activation mediated by the endosomal adaptor protein, adaptor protein with phosphotyrosine binding, pleckstrin homology domains, and leucine zipper motif.

Cardiac-specific suppression of NF-κB signaling prevents diabetic cardiomyopathy via inhibition of the renin-angiotensin system

Activation of NF-κB signaling in the heart may be protective or deleterious depending on the pathological context. In diabetes, the role of NF-κB in cardiac dysfunction has been investigated using pharmacological approaches that have a limitation of being nonspecific. Furthermore, the specific cellular pathways by which NF-κB modulates heart function in diabetes have not been identified. To address these questions, we used a transgenic mouse line expressing mutated IκB-α in the heart (3M mice), which prevented activation of canonical NF-κB signaling. Diabetes was developed by streptozotocin injections in wild-type (WT) and 3M mice. Diabetic WT mice developed systolic and diastolic cardiac dysfunction by the 12th week, as measured by echocardiography. In contrast, cardiac function was preserved in 3M mice up to 24 wk of diabetes. Diabetes induced an elevation in cardiac oxidative stress in diabetic WT mice but not 3M mice compared with nondiabetic control mice. In diabetic WT mice, an increase in the phospholamban/sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 ratio and decrease in ryanodine receptor expression were observed, whereas diabetic 3M mice showed an opposite effect on these parameters of Ca(2+) handling. Significantly, renin-angiotensin system activity was suppressed in diabetic 3M mice compared with an increase in WT animals. In conclusion, these results demonstrate that inhibition of NF-κB signaling in the heart prevents diabetes-induced cardiac dysfunction through preserved Ca(2+) handling and inhibition of the cardiac renin-angiotensin system.

[Role of renal inflammation in the physiopathology of salt-sensitive hypertension]

Salt-sensitive hypertension is produced by a decrease in salt renal excretion after a salt overload. Over the last few years, a new theory has been developed to explain this condition based on renal tissue inflammation. This process begins with free radicals production in renal tissue due to oxidative metabolism. Then they favor a renal inflammation mechanism with T-lymphocytes infiltration and other immune cells. Essentially, T-lymphocytes determine an increase in angiotensin ii production which raises sodium and water retention. Association among autoimmune diseases and hypertension may be explained, in part, by the relationship between salt-sensitive hypertension and renal inflammation. The use of antioxidant drugs and the development of new medicaments may be a choice for treating patients affected with this condition.

JAK-STAT and the renin-angiotensin system: The role of the JAK-STAT pathway in blood pressure and intrarenal renin-angiotensin system regulation

The renin-angiotensin system (RAS) plays important roles in blood pressure control and tissue disease. An inappropriate local angiotensin II elevation in the kidneys leads to the development of hypertension, tissue damage and chronic injury. Studies have demonstrated that the JAK-STAT pathway mediates angiotensin II-triggered gene transcription. The JAK-STAT pathway in turn, acting as an amplifying system, contributes to further intrarenal RAS activation. These observations prompt the suggestion that the JAK-STAT pathway may be of importance in elucidating the mechanisms RAS-associated tissue injury. Accordingly, this review provides a brief overview of the interactions between the JAK-STAT pathway and the RAS, specifically the RAS expressed in the kidneys.

Angiotensin III induces signal transducer and activator of transcription 3 and interleukin-6 mRNA levels in cultured rat astrocytes

INTRODUCTION

Recently we established that pro-inflammatory actions of angiotensin (Ang) II in astrocytes involved Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), and interleukin-6 (IL-6).

MATERIALS AND METHODS

In our current study, we determined in brainstem and cerebellum whether Ang III also activates STAT3 leading to IL-6 mRNA expression and astrocyte proliferation.

RESULTS

Ang III induced STAT3 phosphorylation in a concentration- and time-dependent manner. Significant STAT3 phosphorylation was rapid and was maximal within 10 min, and with 100 nM Ang III. The Ang AT1 receptor was shown to mediate this action of Ang III. Ang III also significantly induced IL-6 mRNA expression within an hour, and maximal Ang III-mediated IL-6 mRNA expression occurred in the presence of 100 nM Ang III. Ang III-mediated IL-6 mRNA expression occurred by the interaction of the peptide with the Ang AT1 receptor and was mediated by STAT3. In addition, STAT3 was shown to mediate Ang III astrocyte proliferation.

CONCLUSIONS

These findings suggest that Ang III, similar to Ang II, has pro-inflammatory effects since it induces STAT3 leading to an induction of IL-6 mRNA expression, outcomes that lend relevance to the physiological importance of central Ang III.

Small GTPase and regulation of inflammation response in atherogenesis

Small GTPases are key signal transducers from extracellular stimuli to the nucleus that regulate a variety of cellular responses, including changes in gene expression and cell adhesion and migration. Accumulating data have demonstrated that abnormal activation of these small GTPases plays a critical role in the atherosclerosis characterized by vascular abnormalities, especially endothelial dysfunction and inflammation. Here, we discuss the linkage between small GTPases, inflammation, and atherogenesis. First, small GTPases affect gene expression of inflammatory cytokines through proinflammatory signaling pathways, such as nuclear factor-κB, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, interlukin-8, and monocyte chemoattractant protein-1. Then, these molecules regulate the vascular inflammation through cell adhesion and migration. In turn, small GTPases are also regulated by extracellular stimuli, such as L-selectin, thrombin, oxidized phospholipids, and interleukins. Thus, these inflammatory cytokines generate a vicious cycle for small GTPases and inflammatory responses in the atherogenesis.

Angiotensin-converting-enzyme inhibition counteracts angiotensin II-mediated endothelial cell dysfunction by modulating the p38/SirT1 axis

OBJECTIVE

Oxidative stress has been linked to endothelial dysfunction and angiotensin II stimulates the reactive oxygen species production contributing to several cardiovascular diseases. We have studied the chain of events induced by angiotensin-converting-enzyme (ACE) activation in vascular umbilical vein endothelial cells (HUVECs) by using an ACE inhibitor such as zofenoprilat.

METHODS

We used specific assay to measure the superoxide anion production, tetrazolium bromide (MTT) assay for cell viability, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay for cell apoptosis, and western blot for protein analysis in the study.

RESULTS

Zofenoprilat counteracts the superoxide anion production and cell apoptosis induced by angiotensin I treatment by blocking the extrinsic caspase cascade, NF-kB and p38 activation. p38 inhibitor SB203580 reverted the angiotensin II oxidant effects while the p38 constitutively activation, by MKK6 transfection, abrogated the zofenoprilat effects. Characterizing the zofenoprilat downstream effector we found that zofenoprilat reverted the SirT-1 downregulation induced by angiotensin II. p38 activation by angiotensin II was strictly correlated with SirT1 protein downregulation; SB203580 significantly prevented SirT1 downregulation induced by angiotensin II while the p38 constitutive activation abolished SIRT1 protein basal levels. p38 directly bound SirT1 sequestering it in the cytoplasm. SirT1 inhibition by sirtinol annulled zofenoprilat action while SirT1 overexpression reverted the cytotoxic effects of angiotensin II. Finally, zofenoprilat negatively controlled angiotensin I receptor protein expression through SirT1.

CONCLUSION

The p38-SirT1 axis is found markedly relevant in modulating the cardiovascular benefit deriving from ACE-inhibitors and might represent a novel target for innovative drugs in cardiovascular prevention.

Upregulation of sestrin-2 expression protects against endothelial toxicity of angiotensin II

Sestrin-2 (SESN2) is involved in the cellular response to different stress conditions. However, the function of SESN2 in the cardiovascular system remains unknown. In the present study, we tested whether SESN2 has a beneficial effect on vascular endothelial damage induced by angiotensin II (AngII). Firstly, we found that AngII induces expression of SESN2 in human umbilical vein endothelial cells (HUVECs) in a time-dependent and dose-dependent manner. We also found that knockdown of SESN2 using small RNA interference promotes cellular toxicity of AngII, as well as a reduction in cell viability, exacerbation of oxidative stress, and stimulation of apoptosis. In addition, our results show that the c-Jun NH (2)-terminal kinase (JNK)/c-Jun pathway is activated by AngII. Inhibiting the activity of the JNK pathway abolishes the increase in SESN2 induced by AngII. Importantly, overexpression of c-Jun promotes luciferase activity of the SESN2 promoter. These findings suggest that the inductive effect of SESN2 is mediated by the JNK/c-Jun pathway. Our results indicate that the induction of SESN2 acts as a compensatory response to AngII for survival, implying that stimulating expression of SESN2 might be an effective pharmacological target for the treatment of AngII-associated cardiovascular diseases.

Lack of vitamin D receptor causes stress-induced premature senescence in vascular smooth muscle cells through enhanced local angiotensin-II signals

OBJECTIVES

The inhibition of the renal renin-angiotensin system by the active form of vitamin D contributes to the cardiovascular health benefits of a normal vitamin D status. Local production of angiotensin-II in the vascular wall is a potent mediator of oxidative stress, prompting premature senescence. Herein, our objective was to examine the impact of defective vitamin D signalling on local angiotensin-II levels and arterial health.

METHODS

Primary cultures of aortic vascular smooth muscle cells (VSMC) from wild-type and vitamin D receptor-knockout (VDRKO) mice were used for the assessment of cell growth, angiotensin-II and superoxide anion production and expression levels of cathepsin D, angiotensin-II type 1 receptor and p57(Kip2). The in vitro findings were confirmed histologically in aortas from wild-type and VDRKO mice.

RESULTS

VSMC from VDRKO mice produced more angiotensin-II in culture, and elicited higher levels of cathepsin D, an enzyme with renin-like activity, and angiotensin-II type 1 receptor, than wild-type mice. Accordingly, VDRKO VSMC showed higher intracellular superoxide anion production, which could be suppressed by cathepsin D, angiotensin-II type 1 receptor or NADPH oxidase antagonists. VDRKO cells presented higher levels of p57(Kip2), impaired proliferation and premature senescence, all of them blunted upon inhibition of angiotensin-II signalling. In vivo studies confirmed higher levels of cathepsin D, angiotensin-II type 1 receptor and p57(Kip2) in aortas from VDRKO mice.

CONCLUSION

The beneficial effects of active vitamin D in vascular health could be a result of the attenuation of local production of angiotensin-II and downstream free radicals, thus preventing the premature senescence of VSMC.

Effects of valsartan on inflammatory and oxidative stress markers in hypertensive, hyperglycemic patients: an open-label, prospective study

BACKGROUND

Diabetes mellitus and hypertension are aggravated by activation of the renin-angiotensin system caused by increased oxygen stress and local inflammatory responses. Several studies have suggested that angiotensin II type 1 receptors can reduce inflammatory markers (high-sensitivity C-reactive protein [hs-CRP], interleukin [IL]-6, IL-18, soluble vascular cell adhesion molecule [VCAM]-I, and l-selectin) and oxidative stress markers (urinary 8-hydroxy-7,8-dihydro-2'-deoxyguanosine [8-OHdG] and 8-epi-prostaglandin F2α [8-isoprostane]) in hypertensive patients.

OBJECTIVE

The aim of this study was to assess the effects of valsartan, an angiotensin II receptor blocker, on inflammatory and oxidative stress markers in hypertensive patients with mild diabetes or impaired glucose tolerance.

METHODS

In this open-label, prospective study, hypertensive patients aged >20 years with mild diabetes (requiring treatment by diet alone or an oral hypoglycemic), seen on an outpatient basis at the Division of Diabetes, Metabolism, and Endocrinology, Omori Hospital, Toyko, Japan, who were receiving a therapeutic dietary regimen for ≥1 month in the treatment of diabetes or hypertension, were eligible for enrollment. Blood pressure, inflammatory markers (hs-CRP, IL-6, IL-18, VCAM-1, and L-selectin), and oxidative stress markers (urinary 8-OHdG and 8-isoprostane) were monitored before treatment commencement with valsartan (40-80 mg/d) and after 3 months of treatment.

RESULTS

A total of 26 patients (18 men, 8 women; mean [SD] age, 57.7 [11.3] years; mean [SD] weight, 65.3 [13.1] kg) were enrolled in the study. After 3 months of treatment, patients' mean (SD) blood pressure had significantly decreased from 153.1 (11.2)/88.3 (11.4) to 143.7 (13.7)/85.2 (9.0) mm Hg (P < 0.05). Among the inflammatory and oxidative stress markers, hs-CRP, VCAM-1, and urinary 8-OHdG concentrations decreased significantly from 0.231 (0.199) to 0.134 (0.111) mg/dL (P = 0.043), 471.1 (193.9) to 403.2 (135.2) ng/mL (P = 0.012), and 12.12 (5.99) to 8.07 (3.36) ng/mg · creatinine (P = 0.001), respectively. The reductions in these markers were observed in patients regardless of whether or not their glycosylated hemoglobin (HbA1c) concentration improved (defined as a decrease of ≥1% in HbA1c).

CONCLUSION

This small, open-label, prospective study found that a 3-month treatment with valsartan was associated with a significant reduction of hs-CRP, VCAM-1, and urinary 8-OHdG concentrations independent of improvement in HbA1c concentration in these hypertensive patients with hyperglycemia.

Angiotensin II induces mitochondrial dysfunction and promotes apoptosis via JNK signalling pathway in primary mouse calvaria osteoblast

OBJECTIVES

This present study was designed to investigate the effects of Angiotensin II on mitochondrial functions, ROS generation and c-jun N-terminal kinases (JNK) signalling pathway-mediated cell apoptosis in mouse calvaria osteoblasts.

METHODS

Calvaria osteoblast were isolated and cultured. The cells were separated into two groups-control and treated groups-where the latter was stimulated with angiotensin II (Ang II). Mitochondrial reactive oxygen species (ROS) and superoxide production were measured. Intracellular ATP levels were also detected. The cell proliferation rate was determined for the two groups. Protein production such as Anti-Bax, Bcl-2, COX IV and activation of c-jun N-terminal kinases signal (JNK) pathway was measured by enzyme-linked immunosorbent assay (ELISA) methods and Western blotting in this study.

RESULTS

Ang II treated cells showed significantly higher levels of superoxide production compared to the control group (p<0.05). Conversely, Ang II induced inhibitory effects on mitochondrial respiratory enzyme complexes, cause membrane potential dissipation, ATP loss and promote ROS generation, cell apoptosis in cultured osteoblasts. In addition, JNK phosphorylations were involved in activating the mitochondria-dependent apoptotic pathway following Ang II stimulation, as pre-treatment of JNK-specific inhibitor SP600125 could rescue osteoblast cells from apoptosis by enhancing the anti-apoptotic protein Bcl-2 expressions, suppressing the translocation of Bax from cytosol into mitochondria, blocking cytochrome C release and caspase-3 activation.

CONCLUSIONS

Ang II stimulates osteoblast apoptosis via suppression of the mitochondrial respiratory enzymes, membrane potential and cellular ATP productions. Clinical application with Ang II-stimulated osteoblast could be used for modelling or bone resorption in the oral region.

Beneficial effects of rosuvastatin treatment in patients with metabolic syndrome

We determined the effect of 6-month rosuvastatin treatment on blood lipids, oxidative parameters, apolipoproteins, high-sensitivity C-reactive protein, lipoprotein(a), homocysteine, and glycated hemoglobin (HbA1c) in patients with metabolic syndrome (MetS). Healthy individuals (men aged >40 years and postmenopausal women) with a body mass index ≥ 30 (n = 100) who fulfilled the National Cholesterol Education Program Adult Treatment Panel III diagnostic criteria for MetS were included. Total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels decreased (P < .0001). The change in LDL 1 to 3 subgroups was significant (P = .0007, P < .0001, and P = .006, respectively). Changes in LDL 4 to 7 subgroups were not significant. There was a beneficial effect on oxidized LDL, fibrinogen, homocysteine, and HbA1c. Rosuvastatin significantly increased high-density lipoprotein levels (P = .0003). The oxidant/antioxidant status and subclinical inflammatory state were also beneficially changed. Rosuvastatin had a significant beneficial effect on atherogenic dyslipidemia as well as on oxidative stress and inflammatory biomarkers in patients with MetS.

Suppressive effects of irbesartan on inflammation and apoptosis in atherosclerotic plaques of apoE-/- mice: molecular imaging with 14C-FDG and 99mTc-annexin A5

OBJECTIVES

To investigate the effects of irbesartan on inflammation and apoptosis in atherosclerotic plaques by histochemical examination and molecular imaging using (14)C-FDG and (99m)Tc-annexin A5.

BACKGROUND

Irbesartan has a peroxisome proliferator-activated receptor gamma (PPARγ) activation property in addition to its ability to block the AT1 receptor. Accordingly, irbesartan may exert further anti-inflammatory and anti-apoptotic effects in atherosclerotic plaques. However, such effects of irbesartan have not been fully investigated. Molecular imaging using (18)F-FDG and (99m)Tc-annexin A5 is useful for evaluating inflammation and apoptosis in atherosclerotic plaques.

METHODS

Female apoE(-/-) mice were treated with irbesartan-mixed (50 mg/kg/day) or irbesartan-free (control) diet for 12 weeks (n = 11/group). One week after the treatment, the mice were co-injected with (14)C-FDG and (99m)Tc-annexin A5, and cryostat sections of the aortic root were prepared. Histochemical examination with Movat's pentachrome (plaque size), Oil Red O (lipid deposition), Mac-2 (macrophage infiltration), and TUNEL (apoptosis) stainings were performed. Dual-tracer autoradiography was carried out to evaluate the levels of (14)C-FDG and (99m)Tc-annexin A5 in plaques (%ID×kg). In vitro experiments were performed to investigate the mechanism underlying the effects.

RESULTS

Histological examination indicated that irbesartan treatment significantly reduced plaque size (to 56.4%±11.1% of control), intra-plaque lipid deposition (53.6%±20.2%) and macrophage infiltration (61.9%±20.8%) levels, and the number of apoptotic cells (14.5%±16.6%). (14)C-FDG (43.0%±18.6%) and (99m)Tc-annexin A5 levels (45.9%±16.8%) were also significantly reduced by irbesartan treatment. Irbesartan significantly suppressed MCP-1 mRNA expression in TNF-α stimulated THP-1 monocytes (64.8%±8.4% of un-treated cells). PPARγ activation was observed in cells treated with irbesartan (134%±36% at 3 µM to 3329%±218% at 81 µM) by a PPARγ reporter assay system.

CONCLUSIONS

Remissions of inflammation and apoptosis as potential therapeutic effects of irbesartan on atherosclerosis were observed. The usefulness of molecular imaging using (18)F-FDG and (99m)Tc-annexin A5 for evaluating the therapeutic effects of irbesartan on atherosclerosis was also suggested.

Effect of candesartan on the expression of sclera-choroidal intercellular adhesion molecule-1 in hypercholesterolemic models

OBJECTIVE

To evaluate the effect of blocking the angiotensin II AT-1 receptor by the systemic administration of candesartan on the expression of intercellular adhesion molecule-1 in the sclera and choroid of hypercholesterolemic rabbits.

METHODS

New Zealand rabbits were divided into 3 groups, as follows: GI, which was fed a rabbit standard diet; GII, which was fed a hypercholesterolemic diet; and GIII, which received hypercholesterolemic diet plus candesartan. Samples of the rabbits' sclera and choroid were then studied by hematoxylin-eosin staining and histomorphometric and immunohistochemical analyses for intercellular adhesion molecule-1 expression.

RESULTS

Histological analysis of hematoxylin- and eosin-stained sclera and choroid revealed that macrophages were rarely present in GI, and GII had significantly increased macrophage numbers compared to GIII. Moreover, in GII, the sclera and choroid morphometry showed a significant increase in thickness in comparison to GI and GIII. GIII presented a significant increase in thickness in relation to GI. Sclera and choroid immunohistochemical analysis for intercellular adhesion molecule-1 expression revealed a significant increase in immunoreactivity in GII in relation to GI and GIII. GIII showed a significant increase in immunoreactivity in relation to GI.

CONCLUSION

Candesartan reduced the expression of intercellular adhesion molecule-1 and consequently macrophage accumulation in the sclera and choroid of hypercholesterolemic rabbits.

Adiponectin expression protects against angiotensin II-mediated inflammation and accelerated atherosclerosis

Adiponectin (APN), an adipocytokine produced by adipose tissue, exerts pleiotropic actions regulating inflammation, metabolism and vascular homeostasis. APN levels are inversely correlated with obesity, type-2 diabetes, hypertension and cardiovascular disease. Although renin angiotensin system (RAS) activation in these interrelated metabolic syndrome components increases angiotensin II (AngII) levels leading to vascular damage, it is unknown whether APN under these conditions provides atheroprotection. We investigated whether increasing plasma APN provides atheroprotection in a hypertensive and accelerated atherosclerosis model. Using adenoviral gene transfer, sustained APN expression increased plasma levels of total and high-molecular weight APN, leading to a significant elevation of plasma HDL-cholesterol (HDL-C). Elevated APN levels were strongly atheroprotective, yet had no impact on blood pressure. Notably, gene expression analyses revealed that APN significantly inhibited the expression of pro-inflammatory and atherogenic genes while it increased the expression of the anti-inflammatory cytokine, IL-10 and the cholesterol efflux transporters, ABCA1 and ABCG1 in the artery wall. These findings suggest that increasing APN levels may be an effective therapeutic strategy to inhibit vascular inflammation and accelerated atherosclerosis associated with RAS activation in the metabolic syndrome.