Chronic hypertension induces cardiac remodeling, including left ventricular hypertrophy and fibrosis, through a combination of both hemodynamic and humoral factors. In previous studies, we showed that the heptapeptide ANG-(<em>1</em>-<em>7</em>) prevented mitogen-stimulated growth of cardiac myocytes in vitro, through a reduction in the activity of the MAPKs ERK<em>1</em> and ERK2. In this study, saline- or ANG II-infused rats were treated with ANG-(<em>1</em>-<em>7</em>) to determine whether the heptapeptide reduces myocyte hypertrophy in vivo and to identify the signaling pathways involved in the process. ANG II infusion into normotensive rats elevated systolic blood pressure >50 mmHg, in association with increased myocyte cross-sectional area, ventricular atrial natriuretic peptide mRNA, and ventricular brain natriuretric peptide mRNA. Although infusion with ANG-(<em>1</em>-<em>7</em>) had no effect on the ANG II-stimulated elevation in blood pressure, the heptapeptide hormone significantly reduced the ANG II-mediated increase in myocyte cross-sectional area, interstitial fibrosis, and natriuretic peptide mRNAs. ANG II increased phospho-ERK<em>1</em> and phospho-ERK2, whereas cotreatment with ANG-(<em>1</em>-<em>7</em>) reduced the phosphorylation of both MAPKs. Neither ANG II nor ANG-(<em>1</em>-<em>7</em>) altered the ERK<em>1</em>/2 MAPK kinase MEK<em>1</em>/2. However, ANG-(<em>1</em>-<em>7</em>) infusion, with or without ANG II, increased the MAPK phosphatase dual-specificity phosphatase (DUSP)-<em>1</em>; in contrast, treatment with ANG II had no effect on DUSP-<em>1</em>, suggesting that ANG-(<em>1</em>-<em>7</em>) upregulates DUSP-<em>1</em> to reduce ANG II-stimulated ERK activation. These results indicate that ANG-(<em>1</em>-<em>7</em>) attenuates cardiac remodeling associated with a chronic elevation in blood pressure and upregulation of a MAPK phosphatase and may be cardioprotective in patients with hypertension.

We determined whether neutrophil recruitment induced by the T-lymphocyte cytokine, interleukin-<em>1</em><em>7</em> (IL-<em>1</em><em>7</em>) is modulated by tachykinins in airways in vivo. Cell recruitment into airways was induced by either human (h) IL-<em>1</em><em>7</em> (<em>1</em> microgram) or rat (r) IL-<em>1</em>beta (2. 5 ng), instilled intratracheally in rats (n = 5 to <em>7</em>). Six hours after instillation, hIL-<em>1</em><em>7</em> (3.<em>1</em> +/- <em>1</em>.2 x <em>1</em>0(6) cells/ml) and rIL-<em>1</em>beta (4.<em>1</em> +/- 0.5 x <em>1</em>0(6) cells/ml), respectively, induced a significant and selective increase in neutrophil count in bronchoalveolar lavage fluid (BAL) when compared with vehicle (0.6 +/- 0.2 x <em>1</em>0(6) cells/ml). For hIL-<em>1</em><em>7</em>, this effect was dose-dependent. Inhalation of peptidase inhibitors (phosphoramidon plus captopril) potentiated the effect of both hIL-<em>1</em><em>7</em> and rIL-<em>1</em>beta. Inhalation of a neutral endopeptidase inhibitor (phosphoramidon) alone also increased the neutrophil count for hIL-<em>1</em><em>7</em>, whereas an <em>angiotensin</em>-converting enzyme inhibitor (captopril) alone did not. A selective neurokinin (NK)-<em>1</em> receptor antagonist (SR <em>1</em>40333) reduced the neutrophil count, both with and without phosphoramidon pretreatment. In conclusion, IL-<em>1</em><em>7</em> selectively recruits neutrophils into rat airways in vivo and this effect is modulated by endogenous tachykinins acting via NK-<em>1</em> receptors.

<em>1</em>. We have measured arterial blood pressure between <em>1</em><em>1</em>5 and <em>1</em>45 days gestation in normally grown fetal sheep (control group; n = <em>1</em>6) and in fetal sheep in which growth was restricted by experimental restriction of placental growth and development (PR group; n = <em>1</em>3). There was no significant difference in the mean gestational arterial blood pressure between the PR (42.<em>7</em> +/- 2.6 mmHg) and control groups (3<em>7</em>.<em>7</em> +/- 2.3 mmHg). Mean arterial blood pressure and arterial PO2 were significantly correlated in control animals (r = 0.53, P < 0.05, n = <em>1</em>6), but not in the PR group. 2. There were no changes in mean arterial blood pressure in either the PR or control groups in response to captopril (<em>7</em>.5 microg captopril min-<em>1</em>; PR group n = <em>7</em>, control group n = 6) between <em>1</em><em>1</em>5 and <em>1</em>25 days gestation. After <em>1</em>35 days gestation, there was a significant decrease (P < 0.05) in the fetal arterial blood pressure in the PR group but not in the control group during the captopril infusion (<em>1</em>5 microg captopril min-<em>1</em>; PR group n = <em>7</em>, control group n = 6). 3. There was a significant effect (F = <em>1</em>4.<em>7</em>5; P < 0.00<em>1</em>) of increasing doses of <em>angiotensin</em> II on fetal diastolic blood pressure in the PR and control groups. The effects of <em>angiotensin</em> II were different (F = 8.6<em>7</em>; P < 0.05) in the PR and control groups at both gestational age ranges. 4. These data indicate that arterial blood pressure may be maintained by different mechanisms in growth restricted fetuses and normally grown counterparts and suggests a role for the fetal renin-<em>angiotensin</em> system in the maintenance of blood pressure in growth restricted fetuses.

BACKGROUND

This study aimed to estimate the association between antihypertensive therapy and mortality in patients with autosomal dominant polycystic kidney disease (ADPKD).

METHODS

Cohort study.

METHODS

Participants with ADPKD from the UK General Practice Research Database older than <em>1</em>5 years between <em>1</em>99<em>1</em> and 2008.

METHODS

Use of 5 major classes of antihypertensive drug.

RESULTS

Deaths, new renal replacement therapy events.

METHODS

Random-effects Poisson models were adjusted for age, sex, year of entry into the cohort, calendar year, prevalent coronary heart disease, stroke, diabetes, hyperlipidemia, and lipid-lowering therapy.

RESULTS

From <em>1</em>99<em>1</em>-2008, there were 2,085 cases of ADPKD, with <em>1</em>,8<em>7</em><em>7</em> contributing person-time for ages older than <em>1</em>5 years. In <em>1</em>99<em>1</em>, antihypertensive drugs were not prescribed for 68% of participants, which decreased to 38% by 2008. The proportion for which <em>1</em> class of antihypertensive drug was prescribed increased from <em>1</em>9% in <em>1</em>99<em>1</em> to 24% in 2008; 2 classes, from <em>1</em><em>1</em>% to 22%; 3 classes, from 2% to <em>1</em><em>1</em>%; and 4 or 5 classes, from <em>1</em>% to 5%. In <em>1</em>99<em>1</em>, drugs acting on the renin-<em>angiotensin</em> system were prescribed for only <em>7</em>% of participants; by 2008, this had increased to 46%. There was evidence of a trend toward decreasing mortality as the number of antihypertensive drug classes prescribed in a year increased. For participants with 3 classes of drugs prescribed, the incident rate ratio was 0.<em>1</em><em>1</em> (95% CI, 0.05-0.2<em>1</em>; P < 0.00<em>1</em>). Each annual increment in year of entry into the cohort was associated with a 6% (95% CI, 2%-<em>1</em>0%; P = 0.008) decrease in mortality.

CONCLUSIONS

Reported associations might be accounted for by unmeasured or incompletely measured confounders. These might include changes in other aspects of medical care for patients with ADPKD.

CONCLUSIONS

Increasing coverage and intensity of antihypertensive therapy is associated with decreasing mortality in people with ADPKD.

The aim of the present study was to evaluate plasma renin activity (PRA) and <em>Angiotensin</em> (Ang) levels [Ang I, Ang II and Ang-(<em>1</em>-<em>7</em>)] to examine the circulating Renin-<em>Angiotensin</em> System (RAS) in renal disease among children with different forms and stages of chronic renal failure (CRF). Subjects were divided as follows: 32 normotensive healthy subjects, 23 normotensive CRF subjects, 34 hypertensive CRF subjects and 2<em>1</em> subjects with end-stage renal disease (ESRD). Radioimmunoassays for PRA (ngAngI/mL/h) and <em>angiotensin</em> (pg/mL) measurements were performed on all subjects. PRA, Ang I, Ang II and Ang-(<em>1</em>-<em>7</em>) levels were significantly higher in hypertensive CRF subjects when compared with normotensive CRF and healthy subjects (p < 0.05 for all comparisons). No differences were observed between normotensive CRF and healthy subjects. ESRD subjects exhibited a dramatic increase in Ang-(<em>1</em>-<em>7</em>) (25-fold higher than control values). In hypertensive CRF subjects, treatment with <em>angiotensin</em>-converting enzyme inhibitors (ACEi) increased (<em>1</em>.4-fold) plasma Ang-(<em>1</em>-<em>7</em>) and decreased (2.4-fold) Ang II. In ESRD, the use of ACEi produced a similar (<em>1</em>.5-fold) elevation of Ang-(<em>1</em>-<em>7</em>), but no changes in plasma Ang II. Our data showed different circulating RAS profiles between hypertensive and in normotensive CRF subjects. Marked changes in plasma Ang-(<em>1</em>-<em>7</em>) were associated with the presence of hypertension and progression of kidney dysfunction.

<em>Angiotensin</em>-converting enzyme 2 (ACE2) has been suggested to be involved in the central regulation of autonomic function. During chronic heart failure (CHF), elevated central <em>angiotensin</em> II signaling contributes to the sustained increase of sympathetic outflow. This is accompanied by a downregulation of ACE2 in the brain. We hypothesized that central overexpression of ACE2 decreases sympathetic outflow and enhances baroreflex function in CHF. Transgenic mice overexpressing human ACE2 selectively in the brain (SYN-hACE2 [SA]) and wild-type littermates (WT) were used. CHF was induced by permanent coronary artery ligation. Four weeks after coronary artery ligation, both WT and SA mice exhibited a significant decrease in left ventricular ejection fraction (<40%). A slight decrease in mean arterial pressure was found only in SA mice. Compared with WT mice with CHF, brain-selective ACE2 overexpression attenuated left ventricular end-diastolic pressure; decreased urinary norepinephrine excretion; baseline renal sympathetic nerve activity (WT CHF: <em>7</em><em>1</em>.6±<em>7</em>.6% max versus SA CHF: 49.3±6.<em>1</em>% max); and enhanced baroreflex sensitivity (maximum slope: WT sham: <em>1</em>.6<em>1</em>±0.<em>1</em>6%/mm Hg versus SA CHF: <em>1</em>.5<em>1</em>±0.<em>1</em><em>7</em>%/mm Hg). Chronic subcutaneous blockade of mas receptor increased renal sympathetic nerve activity in SA mice with CHF (A<em>7</em><em>7</em>9: 6<em>7</em>.3±5.8% versus vehicle: 46.4±3.6% of max). An upregulation in <em>angiotensin</em> II type <em>1</em> receptor expression was detected in medullary nuclei in WT CHF mice, which was significantly attenuated in SA mice with CHF. These data suggest that central ACE2 overexpression exerts a potential protective effect in CHF through attenuating sympathetic outflow. The mechanism for this effect involves <em>angiotensin</em> (<em>1</em>-<em>7</em>) mas signaling, as well as a decrease in <em>angiotensin</em> II type <em>1</em> receptor signaling in the medulla.

We studied the effect of excessive salt intake on vascular lesion development in hypertensive transgenic mice that overproduce <em>angiotensin</em> II, ie, Tsukuba hypertensive mice (THM). At 6 weeks of age, THM and C5<em>7</em>BL/6J (controls) were given either <em>1</em>% sodium chloride ("salt-loaded") drinking water or tap water for 30 days. Salt-loaded THM, but not controls, suffered frequent thoracic or abdominal cavity hemorrhage. THM mortality after <em>7</em> days of salt loading was 23%; after 30 days of salt loading, it rose to 6<em>7</em>%. Hemorrhaging occurred due to the development of aortic aneurysm and rupture at the aortic arch and aorta near the renal arteries. Vascular lesions progressed with structural degeneration of the aortic media. Electronmicroscopic analysis revealed that intact THM already exhibited vascular remodeling consisting of vascular smooth muscle cells (VSMCs) with developed organelles and an increased extracellular matrix. Salt-loaded THM suffered aggravated vascular hypertrophy and vascular structure destruction by plasma material invasion, necrosis of VSMCs possessing extremely swollen cytoplasm and abundant organelles, and interlamellar bleeding, resulting in aortic aneurysm and eventual rupture. Interestingly, blood pressure levels and heart rates in salt-loaded THM did not differ significantly from those of controls; plasma renin activity between drinking regimens was also comparable between the two groups. Drinking volume and the concentration of atrial natriuretic peptide (ANP) in plasma, however, were significantly higher in salt-loaded THM than in intact THM. In addition to aneurysm localization, the findings regarding drinking volume and plasma ANP suggest that aortic aneurysm and rupture in salt-loaded THM occurred as the result of an unknown mechanical stress, other than blood pressure, on the aortic wall. High salt ingestion is involved in the development of thoracic and abdominal aortic aneurysm in the presence of hypertension in the activated renin-<em>angiotensin</em> system. THM should therefore serve as a useful animal model for studying the pathogenesis of aortic aneurysm accompanied by hypertension.

Plasma aldosterone (A), corticosterone (B), deoxycorticosterone (DOC), progesterone (P), <em>1</em><em>7</em>-hydroxyprogesterone (<em>1</em><em>7</em>-OHP), cortisol (F), and cortisone (E) were measured simultaneously by specific radioimmunoassays in small plasma samples obtained from <em>1</em><em>7</em>4 normal infants and children between 2 hr and <em>1</em>5 yr of age. The significantly elevated neonatal mean levels (ng/ml) of 2.5 (A), 4.<em>1</em> (DOC), 53.0 (P), and 6.6 (<em>1</em><em>7</em>-OHP) dropped significantly during infancy reaching prepubertal levels between 3 months and 3 yr of age, with a transient, significant DOC increase between <em>1</em>--<em>7</em> yr. The glucocorticoids F andB declined significantly from means of 68 and 4.4 to <em>1</em><em>1</em>.4 and 0.28 ng/ml, respectively, during the first weeks of life, then increased significantly reaching adult levels between <em>1</em>--3 yr of age. Mean E fell progressively from <em>7</em>4 ng/ml after birth to <em>1</em>0 ng/ml during <em>1</em>--5 yr (P less than 0.000<em>1</em>), then slightly increased to adult levels. After age <em>7</em> yr, P and <em>1</em><em>7</em>-OHP, in contrast to the other steroids, rose significantly in both boys and girls relative to pubertal development. The observed changes are thought to be due to (<em>1</em>) adaptation of the adrenal neocortex to extrauterine life after disruption of the fetoplacental unit, (2) a physiologic lack of corticosteroid binding globulin (CBG) during infancy due to maturation of hepatic CBG biosynthesis, (3) the functional immaturity of the infant kidney compensated by an increased activity of the renin-<em>angiotensin</em>-aldosterone system, and (4) gradually increasing gonadal secretion of progestins during puberty.

Quantitative autoradiography revealed large numbers of <em>angiotensin</em>-II (AT) receptors in the <em>1</em>8-day-old rat embryo. The selective AT-<em>1</em> antagonist DuP <em>7</em>53 readily competed for AT receptors in liver, lung parenchyma, and choroid plexus, and these receptors are classified as AT-<em>1</em> receptors. The selective AT-2 displacers CGP 42<em>1</em><em>1</em>2 A and/or PD <em>1</em>23<em>1</em><em>7</em><em>7</em> competed with high affinity with AT bound to most receptors located in skeletal muscle, skin, diaphragm, bronchi, and stomach, and these receptors are classified as AT-2 receptors. The amount of AT-2 receptors in fetal tissue was more than <em>1</em>0-fold higher than that of AT-<em>1</em> receptors. In skeletal muscle and skin, DuP <em>7</em>53 competed with AT in the presence of <em>1</em>0(-<em>7</em>) M CGP 42<em>1</em><em>1</em>2 A, indicating the presence of small numbers of AT-<em>1</em> receptors. In liver and lung parenchyma, binding to AT-<em>1</em> receptors was sensitive to guanine nucleotides. AT binding to AT-2 receptors in fetal skin and skeletal muscle was insensitive to guanine nucleotides. AT stimulated phosphoinositide hydrolysis in liver (ED50, 64 nM) and in skin and skeletal muscle (ED50, 62 nM); this was inhibited by DuP <em>7</em>53 (liver IC50, 38 nM; skin and skeletal muscle IC50, 26 nM), but not by PD <em>1</em>23<em>1</em><em>7</em><em>7</em> in concentrations up to the micromolar range. AT-<em>1</em> receptors are probably coupled to G-proteins, and their stimulation increases phosphoinositide hydrolysis. AT-2 receptors may not be linked to G-proteins, their stimulation is not associated with phosphoinositide hydrolysis, and the nature of their second messenger system(s) is presently unknown.

Preeclampsia (PE) is a prevalent life-threatening hypertensive disorder of pregnancy associated with increased complement activation. However, the causative factors and pathogenic role of increased complement activation in PE are largely unidentified. Here we report that a circulating maternal autoantibody, the <em>angiotensin</em> II type <em>1</em> receptor agonistic autoantibody, which emerged recently as a potential pathogenic contributor to PE, stimulates deposition of complement C3 in placentas and kidneys of pregnant mice via <em>angiotensin</em> II type <em>1</em> receptor activation. Next, we provide in vivo evidence that selectively interfering with C3a signaling by a complement C3a receptor-specific antagonist significantly reduces hypertension from <em>1</em>6<em>7</em>±<em>7</em> to <em>1</em>43±5 mm Hg and proteinuria from 223.5±<em>7</em>.5 to <em>7</em>8.8±<em>1</em>4.0 μg of albumin per milligram creatinine (both P<0.05) in <em>angiotensin</em> II type <em>1</em> receptor agonistic autoantibody-injected pregnant mice. In addition, we demonstrated that complement C3a receptor antagonist significantly inhibited autoantibody-induced circulating soluble fms-like tyrosine kinase <em>1</em>, a known antiangiogenic protein associated with PE, and reduced small placental size with impaired angiogenesis and intrauterine growth restriction. Similarly, in humans, we demonstrate that C3 deposition is significantly elevated in the placentas of preeclamptic patients compared with normotensive controls. Lastly, we show that complement C3a receptor activation is a key mechanism underlying autoantibody-induced soluble fms-like tyrosine kinase <em>1</em> secretion and decreased angiogenesis in cultured human villous explants. Overall, we provide mouse and human evidence that <em>angiotensin</em> II type <em>1</em> receptor agonistic autoantibody-mediated activation contributes to elevated C3 and that complement C3a receptor signaling is a key mechanism underlying the pathogenesis of the disease. These studies are the first to link <em>angiotensin</em> II type <em>1</em> receptor agonistic autoantibody with complement activation and to provide important new opportunities for therapeutic intervention in PE.

OBJECTIVE

The purpose of this study was to analyze whether long-term treatment with the nonselective beta-adrenergic blocking agent carvedilol may have beneficial effects in patients with dilated cardiomyopathy (DCM), who are poor responders in terms of left ventricular (LV) function and exercise tolerance to chronic treatment with the selective beta-blocker metoprolol.

BACKGROUND

Although metoprolol has been proven to be beneficial in the majority of patients with heart failure, a subset of the remaining patients shows long-term survival without satisfactory clinical improvement.

METHODS

Thirty consecutive DCM patients with persistent LV dysfunction (ejection fraction < or =40%) and reduced exercise tolerance (peak oxygen consumption <25 ml/kg/min) despite chronic >><em>1</em> year) tailored treatment with metoprolol and <em>angiotensin</em>-converting enzyme inhibitors were enrolled in a <em>1</em>2-month, open-label, parallel trial and were randomized either to continue on metoprolol (n = <em>1</em>6, mean dosage <em>1</em>42+/-44 mg/day) or to cross over to maximum tolerated dosage of carvedilol (n = <em>1</em>4, mean dosage 74+/-23 mg/day).

RESULTS

At <em>1</em>2 months, patients on carvedilol, compared with those continuing on metoprolol, showed a decrease in LV dimensions (end-diastolic volume -8+/-7 vs. +7+/-6 ml/m2, p = 0.053; end-systolic volume -7+/-5 vs. +6+/-4 ml/m2, p = 0.047), an improvement in LV ejection fraction (+7+/-3% vs. -<em>1</em>+/-2%, p = 0.045), a reduction in ventricular ectopic beats (-<em>1</em>2+/-9 vs. +62+/-50 n/h, p = 0.05) and couplets (-0.5+/-0.4 vs. +<em>1</em>.5+/-0.6 n/h, p = 0.048), no significant benefit on symptoms and quality of life and a negative effect on peak oxygen consumption (-0.6+/-0.6 vs. +<em>1</em>.3+/-0.5 ml/kg/min, p = 0.03).

CONCLUSIONS

In DCM patients who were poor responders to chronic metoprolol, carvedilol treatment was associated with favorable effects on LV systolic function and remodeling as well as on ventricular arrhythmias, whereas it had a negative effect on peak oxygen consumption.

OBJECTIVE

To compare two drug regimens to treat resistant hypertension.

METHODS

In a prospective, randomized, open blinded endpoint study, <em>1</em>67 patients with mean baseline daytime ambulatory blood pressure <em>1</em>35 mmHg or more and/or 85 mmHg or more, despite 4 weeks' treatment with irbesartan 300 mg/day, hydrochlorothiazide <em>1</em>2.5 mg/day and amlodipine 5 mg/day, were randomized to sequential nephron blockade (group <em>1</em>, n = 85) or sequential renin-<em>angiotensin</em> system blockade (group 2, n = 82). First, spironolactone 25 mg/day in group <em>1</em> or ramipril 5 mg/day in group 2 were added for 4 weeks. Treatment was increased at weeks 4, 8 or <em>1</em>0 if home blood pressure was <em>1</em>35 mmHg or more and/or 85 mmHg or more by sequentially administering furosemide 20 mg/day, furosemide 40 mg/day and amiloride 5 mg/day in group <em>1</em>, or ramipril <em>1</em>0 mg/day, bisoprolol 5 mg/day and bisoprolol <em>1</em>0 mg/day in group 2. The primary endpoint was change in systolic daytime ambulatory blood pressure at week <em>1</em>2.

RESULTS

At week <em>1</em>2, the mean between-group difference in daytime ambulatory blood pressure was <em>1</em>0/4 mmHg (95% confidence interval: 7-<em>1</em>4/2-7; P < 0.00<em>1</em>/P = 0.00<em>1</em>4) in favour of the group <em>1</em>. The blood pressure goal (daytime ambulatory blood pressure (<em>1</em>35/85 mmHg) was achieved in 58% in the group <em>1</em> and 20% in the group 2 (P < 0.000<em>1</em>). Discontinuation for drug-related adverse events was low (group <em>1</em>, n = 7; group 2, n = 6).

CONCLUSIONS

In patients with resistant hypertension, sequential nephron blockade induces a large and well tolerated reduction in blood pressure via a progressive increase in sodium depletion, and is more effective than sequential renin-angiotensin system blockade.

To determine the role of the local renin-<em>angiotensin</em> system in renal function, micropuncture was performed on two lines of mice in which genetic changes to the <em>angiotensin</em>-converting enzyme (ACE) gene markedly reduced or eliminated the expression of renal tissue ACE. Whereas blood pressure is low in one line (ACE 2/2), it is normal in the other (ACE <em>1</em>/3) due to ectopic hepatic ACE expression. When normalized for renal size, levels of glomerular filtration rate [GFR; microl x min(-<em>1</em>) x g kidney wt(-<em>1</em>) (KW)] and single-nephron GFR (SNGFR; nl x min(-<em>1</em>) x g KW(-<em>1</em>)) were similar between wild-type (WT) and ACE <em>1</em>/3 mice, while both measures were significantly reduced in ACE 2/2 mice (WT: 500 +/- 63 and 4<em>1</em>.<em>7</em> +/- 3.5; ACE <em>1</em>/3: 5<em>1</em>5.8 +/- <em>7</em><em>1</em> and 44.3 +/- 3.3; ACE 2/2: <em>1</em>3<em>1</em>.4 +/- 23 and 30.3 +/- 3.5). Proximal fractional reabsorption was not significantly different between WT and ACE <em>1</em>/3 mice (5<em>1</em> +/- 3.5 and 49 +/- 2.3%), and it was increased significantly in ACE 2/2 mice (<em>7</em>4 +/- 3.5%). Infusion of ANG II (50 ng x kg(-<em>1</em>) x min(-<em>1</em>)) increased mean arterial pressure by approximately <em>7</em> mmHg in all groups of mice and reduced SNGFR in WT and ACE <em>1</em>/3 mice (to 30.9 +/- 2.8 and 3<em>1</em>.9 +/- 2.5 nl x min(-<em>1</em>) x g KW(-<em>1</em>)) while increasing it in ACE 2/2 mice (to 55.3 +/- 5.3 nl x min(-<em>1</em>) x g KW(-<em>1</em>)) despite an increase in total renal vascular resistance. The tubuloglomerular feedback (TGF) response was markedly reduced in ACE <em>1</em>/3 mice (stop-flow pressure change -2.5 +/- 0.9 mmHg) compared with WT despite similar blood pressures (-8.3 +/- 0.6 mmHg). In ACE 2/2 mice, TGF was absent (-0.<em>7</em> +/- 0.2 mmHg). We conclude that the chronic lack of ACE, and presumably ANG II generation, in the proximal tubule was not associated with sustained proximal fluid transport defects. However, renal tissue ACE is an important contributor to TGF.

This study examined the effect of the pharmacological manipulation of adrenal renin-<em>angiotensin</em> system (RAS) on aldosterone secretion from in situ perfused adrenals of rats kept on a normal diet and sodium restricted for <em>1</em>4 days. Neither the <em>angiotensin</em>-converting enzyme inhibitor captopril nor the nonselective <em>angiotensin</em> II receptor antagonist saralasin and the AT(<em>1</em>) receptor-selective antagonist losartan affected basal aldosterone output in normally fed rats. In contrast, they concentration dependently decreased aldosterone secretion in sodium-restricted animals, with maximal effective concentration ranging from <em>1</em>0(-<em>7</em>) to <em>1</em>0(-6) M. Captopril (<em>1</em>0(-6) M), saralasin (<em>1</em>0(-6) M), and losartan (<em>1</em>0(-<em>7</em>) M) counteracted aldosterone response to <em>1</em>0 mM K(+) in sodium-restricted rats but not in normally fed animals. Collectively, these findings provide evidence that adrenal RAS plays a role in the regulation of aldosterone secretion, but only under conditions of prolonged stimulation of zona glomerulosa probably leading to overexpression of adrenal RAS.

After earlier studies in which secretion of aldosterone was demonstrated to be important in rat arterial smooth muscle cell (RASMC) proliferation in vitro, the presence of both <em>1</em><em>1</em>beta-hydroxylase (CYP<em>1</em><em>1</em>B<em>1</em>) and aldosterone synthase (CYP<em>1</em><em>1</em>B2) gene transcription were shown in these cells by real-time reverse transcription-polymerase chain reaction (RT-PCR). In proliferation studies, tritiated thymidine incorporation into RASMC and RASMC cell number were both significantly increased by <em>angiotensin</em> II (Ang II) (<em>1</em>0(-<em>7</em>) mol/L) compared with controls (P<0.0<em>1</em>), but this effect was inhibited by the 3beta-hydroxysteroid-dehydrogenase inhibitor trilostane (<em>1</em>0(-6) mol/L and <em>1</em>0(-5) mol/L, P<0.05). Aldosterone alone added to RASMC did not significantly change tritiated thymidine incorporation when compared with controls, but the Ang II-induced increase was significantly enhanced by aldosterone at <em>1</em>0(-<em>1</em>0) mol/L and <em>1</em>0(-8) mol/L (P<0.05). Neither corticosterone nor <em>1</em>8-hydroxydeoxycorticosterone had any such potentiating effect. RT-PCR analysis and real-time quantitative RT-PCR revealed an increase of Ang II type-<em>1</em> (AT<em>1</em>) receptor mRNA in RASMC treated by aldosterone (<em>1</em>0(-8) mol/L) compared with untreated controls, and this was correlated with a small but significant increase in AT<em>1</em> receptor protein (P<0.05), as assessed by immunoblotting analysis. These data confirm that steroid production by RASMC is critical in the response to Ang II, and the data support the view that aldosterone specifically is required for the full proliferative response to Ang II in RASMC. One way it may act is by modulating the expression and functions of the AT<em>1</em> receptor.

Adenosine (Ado) mediates vasoconstriction via A(<em>1</em>)-Ado receptors and vasodilation via A(2)-Ado receptors in the kidney. It interacts with <em>angiotensin</em> II (Ang II), which is important for renal hemodynamics and tubuloglomerular feedback (TGF). The aim was to investigate the function of Ado receptors in the Ado-Ang II interaction in mouse microperfused, afferent arterioles. Ado (<em>1</em>0(-<em>1</em><em>1</em>)-<em>1</em>0(-4) mol/l) caused a biphasic response: arteriolar diameters were reduced (-<em>7</em>%) at Ado <em>1</em>0(-<em>1</em><em>1</em>)-<em>1</em>0(-9) mol/l and returned to control values at higher concentrations. Treatment with Ang II (<em>1</em>0(-<em>1</em>0) mol/l) transformed the response into a concentration-dependent constriction. N(6)-cyclopentyladenosine (A(<em>1</em>)-Ado receptor agonist) reduced diameters (<em>1</em>2% at <em>1</em>0(-6) mol/l). Application of CGS2<em>1</em>680 (<em>1</em>0(-<em>1</em>2)-<em>1</em>0(-4) mol/l, A(2A) receptor agonist) increased the diameter by <em>1</em>3%. Pretreatment with ZM24<em>1</em>385 (A(2A)-Ado receptor antagonist) alone or in combination with MRS<em>1</em><em>7</em>06 (A(2B)-Ado receptor antagonist) resulted in a pure constriction upon Ado, whereas 8-cyclopentyltheophylline (CPT) (A(<em>1</em>)-Ado receptor antagonist) inhibited the constrictor response. Afferent arterioles of mice lacking A(<em>1</em>)-Ado receptor did not show constriction upon Ado. Treatment with Ado (<em>1</em>0(-8) mol/l) increased the response upon Ang II, which was blocked by CPT. Ado (<em>1</em>0(-5) mol/l) did not influence the Ang II response, but an additional blockade of A(2)-Ado receptors enhanced it. The action of Ado on constrictor A(<em>1</em>)-Ado receptors and dilatory A(2)-Ado receptors modulates the interaction with Ang II. Both directions of Ado-Ang II interaction, which predominantly leads to an amplification of the contractile response, are important for the operation of the TGF.

OBJECTIVE

We studied the association between mitochondrial aldehyde dehydrogenase (ALDH2) Glu504Lys (rs6<em>7</em><em>1</em> or ALDH2*2) polymorphism and coronary artery disease (CAD), and sought to clarify the mechanisms underlying this association.

METHODS

The ALDH2 rs6<em>7</em><em>1</em> polymorphism was genotyped in 4<em>1</em><em>7</em> CAD patients and 448 age- and gender-matched controls. All participants were Han Chinese. Human umbilical vein endothelial cells (HUVECs) isolated from <em>1</em><em>1</em> human umbilical cords were genotyped, cultured, and exposed to <em>angiotensin</em> II (Ang II, <em>1</em>0(-<em>7</em>)-<em>1</em>0(-5)mol/L). Dimethylarginine dimethylaminohydrolase <em>1</em> (DDAH<em>1</em>) mRNA expression levels were determined by real-time PCR. Levels of asymmetric dimethylarginine (ADMA) in culture media and cell lysates were determined by high performance liquid chromatography-mass spectrometry (HPLC-MS).

RESULTS

The frequency of carriers of the ALDH2 rs6<em>7</em><em>1</em> A allele (GA+AA) was significantly higher in patients with CAD (4<em>7</em>.5%) than in controls (35.0%, p=0.0002). After adjustment for potential confounders, the odds ratio (OR) for CAD for carriers of the rs6<em>7</em><em>1</em> A allele was <em>1</em>.85 (95% confidence interval [CI]: <em>1</em>.38-2.49, p=0.00005) in the entire study cohort, and <em>1</em>.95 (95% CI: <em>1</em>.40-2.<em>7</em>0, p=0.0000<em>7</em>) in non-drinkers. In non-drinking controls, the homozygous rs6<em>7</em><em>1</em> AA genotype was associated with significantly lower high-density lipoprotein cholesterol (HDL-C) concentrations compared with rs6<em>7</em><em>1</em> GG homozygotes (p=0.0<em>1</em>5). HUVEC cells homozygous for the G allele of rs6<em>7</em><em>1</em> showed a significantly higher DDAH<em>1</em> mRNA expression and lower intracellular ADMA levels compared with heterozygous GA cells (p<0.05, respectively). In homozygous GG cells, high concentrations of Ang II (<em>1</em>0(-5)mol/L) decreased DDAH<em>1</em> mRNA expression and increased intracellular ADMA concentrations.

CONCLUSIONS

The rs6<em>7</em><em>1</em> polymorphism of ALDH2 is associated with CAD in Han Chinese, possibly by influencing HDL-C levels and endothelial ADMA levels.

BACKGROUND

Adiponectin has antiinflammatory and vascular protective effects and may improve insulin sensitivity. Animal data suggest a role of the renin-angiotensin aldosterone system (RAAS) in the regulation of adiponectin.

OBJECTIVE

Our objective was to investigate the role of the RAAS in regulation of adiponectin in humans in vivo. To this purpose we studied the effects of physiological (change in sodium status) and pharmacological modulation of RAAS activity (angiotensin II infusion and enalapril treatment) on plasma adiponectin.

METHODS

Thirty-five healthy male volunteers (aged 26 +/- 9 yr) were studied after two 7-d periods: one on a low-sodium diet (LS, 50 mmol Na(+) per day) and one on a high-sodium diet (HS, 200 mmol Na(+) per day). At the end of each period, adiponectin was measured, and its response to angiotensin II infusion (0.3, 1, and 3 ng/kg.min all during 1 h) was determined. Additionally, all subjects received 1 wk treatment of enalapril 20 mg once daily (angiotensin converting enzyme inhibition) during the HS.

METHODS

We measured plasma adiponectin concentrations during LS and HS and in response to angiotensin II infusion.

RESULTS

The suppression of the RAAS by HS elicited a significant rise in adiponectin [LS baseline, 11.9 (8.3-16.2) microg/liter; HS baseline, 14.4 (11.2-20.4) microg/liter; P < 0.05]. All doses of angiotensin II elicited a profound decrease in adiponectin during both conditions [LS 3 ng/kg.min, 7.4 (6.3-8.9) microg/liter; HS 3 ng/kg.min, 8.4 (7.3-9.9) microg/liter; both P < 0.001 vs. baseline]. Angiotensin converting enzyme inhibition induced a significant rise in adiponectin [16.6 (10.6-20.9) microg/liter, P < 0.05 vs. HS].

CONCLUSIONS

Physiological and pharmacological modulation of RAAS affects plasma adiponectin with lower concentrations during the high angiotensin II conditions. The therapeutic potential of RAAS blockade as a tool to correct hypoadiponectinemia should be explored further.

Hyperactivity of the renin-<em>angiotensin</em>-aldosterone system through the <em>angiotensin</em> II (Ang II)/Ang II type <em>1</em> receptor (AT<em>1</em>-R) axis constitutes a hallmark of hypertension. Recent findings indicate that only a subset of AT<em>1</em>-R signaling pathways is cardiodeleterious, and their selective inhibition by biased ligands promotes therapeutic benefit. To date, only synthetic biased ligands have been described, and whether natural renin-<em>angiotensin</em>-aldosterone system peptides exhibit functional selectivity at AT<em>1</em>-R remains unknown. In this study, we systematically determined efficacy and potency of Ang II, Ang III, Ang IV, and Ang-(<em>1</em>-<em>7</em>) in AT<em>1</em>-R-expressing HEK293T cells on the activation of cardiodeleterious G-proteins and cardioprotective β-arrestin2. Ang III and Ang IV fully activate similar G-proteins than Ang II, the prototypical AT<em>1</em>-R agonist, despite weaker potency of Ang IV. Interestingly, Ang-(<em>1</em>-<em>7</em>) that binds AT<em>1</em>-R fails to promote G-protein activation but behaves as a competitive antagonist for Ang II/Gi and Ang II/Gq pathways. Conversely, all renin-<em>angiotensin</em>-aldosterone system peptides act as agonists on the AT<em>1</em>-R/β-arrestin2 axis but display biased activities relative to Ang II as indicated by their differences in potency and AT<em>1</em>-R/β-arrestin2 intracellular routing. Importantly, we reveal Ang-(<em>1</em>-<em>7</em>) a known Mas receptor-specific ligand, as an AT<em>1</em>-R-biased agonist, selectively promoting β-arrestin activation while blocking the detrimental Ang II/AT<em>1</em>-R/Gq axis. This original pharmacological profile of Ang-(<em>1</em>-<em>7</em>) at AT<em>1</em>-R, similar to that of synthetic AT<em>1</em>-R-biased agonists, could, in part, contribute to its cardiovascular benefits. Accordingly, in vivo, Ang-(<em>1</em>-<em>7</em>) counteracts the phenylephrine-induced aorta contraction, which was blunted in AT<em>1</em>-R knockout mice. Collectively, these data suggest that Ang-(<em>1</em>-<em>7</em>) natural-biased agonism at AT<em>1</em>-R could fine-tune the physiology of the renin-<em>angiotensin</em>-aldosterone system.

Despite many therapeutic advances leading to increasingly effective drug treatments, thrombotic events (such as ischaemic stroke, pulmonary embolism, deep venous thrombosis and acute myocardial infarction) still represent a major worldwide cause of morbidity and mortality. Remarkable effort has been made to identify new drug targets. There is growing evidence indicating that the recently described counter-regulator axis of the renin-<em>angiotensin</em> system (RAS), composed of <em>Angiotensin</em>-Converting Enzyme 2 (ACE2), <em>Angiotensin</em>-(<em>1</em>-<em>7</em>) and the Mas receptor, has protective effects against thrombosis. In addition, it could be considered as a promising target for treating or preventing this disease. In this narrative review, we focused on the recent findings of the role of the ACE2/<em>Angiotensin</em>-(<em>1</em>-<em>7</em>)/Mas axis on the haemostatic process and its therapeutic potential.

OBJECTIVE

Angiotensin II receptor antagonists have been proposed as new drugs for portal hypertension. This randomized, placebo-controlled, double-blind study aimed to assess the effect of the angiotensin II receptor antagonist irbesartan on portal and systemic hemodynamics and renal function in patients with cirrhosis.

METHODS

Thirty-six patients with cirrhosis and portal hypertension received 150 mg/d irbesartan or placebo for 1 week. Systemic hemodynamics, kidney and liver function parameters were recorded regularly; hepatic venous pressure gradient and plasma renin were assessed on days 0 and 7.

RESULTS

Irbesartan reduced the hepatic venous pressure gradient by 12.2% +/- 6.6% (P < 0.05) and mean arterial pressure by 5.3% +/- 4.0% in 13 of 18 verum patients. In 4 (22%) verum patients, arterial hypotension, accompanied by significant renal impairment, required withdrawal of irbesartan. In these patients, baseline plasma renin (P < 0.002) and cystatin C (P < 0.001) levels were higher, and creatinine clearance (P < 0.02), serum sodium (P < 0.01), and albumin (P < 0.05) were lower than in patients who tolerated irbesartan. Four of five patients with baseline renin >900 microU/mL developed treatment-limiting hypotension.

CONCLUSIONS

The angiotensin II receptor antagonist irbesartan is not advisable in patients with advanced cirrhosis and high plasma renin because it may induce arterial hypotension and only moderately reduces portal pressure.

<em>Angiotensin</em>-(<em>1</em>-<em>7</em>) [Ang-(<em>1</em>-<em>7</em>)] has biological actions that can often be distinguished from those of <em>angiotensin</em> II (Ang II). Recent studies indicate that the effects of Ang-(<em>1</em>-<em>7</em>) are mediated by specific receptor(s). We now report the partial characterization of a new antagonist selective for Ang-(<em>1</em>-<em>7</em>), D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>). D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>) (50 pmol) inhibited the hypertensive effect induced by microinjection of Ang-(<em>1</em>-<em>7</em>) [4+/-<em>1</em> vs 2<em>1</em>+/-2 mm Hg, 25 pmol Ang-(<em>1</em>-<em>7</em>) alone] into the rostral ventrolateral medulla without changing the effect of Ang II (<em>1</em>6+/-2.5 vs <em>1</em>9+/-2.5 mm Hg after 25 pmol Ang II alone). At <em>1</em>0(-<em>7</em>) mol/L concentration, it completely blocked the endothelium-dependent vasorelaxation produced by Ang-(<em>1</em>-<em>7</em>) (<em>1</em>0(-<em>1</em>0) to <em>1</em>0(-6) mol/L) in the mouse aorta. The antidiuresis produced by Ang-(<em>1</em>-<em>7</em>) (40 pmol/<em>1</em>00 g body weight) in water-loaded rats was also blocked by its analog [<em>1</em> microg/<em>1</em>00 g body weight; 3.08+/-0.8 vs <em>1</em>.2<em>7</em>+/-0.33 mL in Ang-(<em>1</em>-<em>7</em>)-treated rats]. D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>) at a molar ratio of 40:<em>1</em> did not change the hypotensive effect of bradykinin. Moreover, D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>) did not affect the dipsogenic effect produced by intracerebroventricular administration of Ang II (<em>1</em><em>1</em>.4+/-<em>1</em>.<em>1</em>5 vs 8.8+/-<em>1</em>.2 mL/h after Ang II) and did not show any demonstrable <em>angiotensin</em>-converting enzyme inhibitory activity in assays with the synthetic substrate Hip-His-Leu and rat plasma as a source of enzyme. Autoradiography studies with <em>1</em>25I-Ang-(<em>1</em>-<em>7</em>) in mouse kidney slices showed that D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>) competed for the binding of Ang-(<em>1</em>-<em>7</em>) to the cortical supramedullary region. In Chinese hamster ovary cells stably transfected with the AT<em>1</em> receptor subtype, D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>) did not compete for the specific binding of <em>1</em>25I-Ang-II in concentrations up to <em>1</em>0(-6) mol/L. There was also no significant displacement of Ang II binding to <em>angiotensin</em> type 2 receptors in membrane preparations of adrenal medulla. These data indicate that D-Pro<em>7</em>-Ang-(<em>1</em>-<em>7</em>) is a selective antagonist for Ang-(<em>1</em>-<em>7</em>), which can be useful to clarify the functional role of this heptapeptide.

We examined whether xanthine oxidoreductase (XOR), a hypoxia-inducible enzyme capable of generating reactive oxygen species, is involved in the onset of <em>angiotensin</em> (Ang) II-induced vascular dysfunction in double-transgenic rats (dTGR) harboring human renin and human <em>angiotensin</em>ogen genes. In <em>7</em>-week-old hypertensive dTGR, the endothelium-mediated relaxation of noradrenaline (NA)-precontracted renal arterial rings to acetylcholine (ACh) in vitro was markedly impaired compared with Sprague Dawley rats. Preincubation with superoxide dismutase (SOD) improved the endothelium-dependent vascular relaxation, indicating that in dTGR, endothelial dysfunction is associated with increased superoxide formation. Preincubation with the XOR inhibitor oxypurinol also improved endothelium-dependent vascular relaxation. The endothelium-independent relaxation to sodium nitroprusside was similar in both strains. In dTGR, serum 8-isoprostaglandin F(2alpha), a vasoconstrictor and antinatriuretic arachidonic acid metabolite produced by oxidative stress, was increased by <em>1</em>00%, and the activity of XOR in the kidney was increased by 40%. Urinary nitrate plus nitrite (NO(x)) excretion, a marker of total body NO generation, was decreased by 85%. Contractile responses of renal arteries to Ang II, endothelin-<em>1</em> (ET-<em>1</em>), and NA were decreased in dTGR, suggesting hypertension-associated generalized changes in the vascular function rather than a receptor-specific desensitization. Valsartan (30 mg/kg PO for 3 weeks) normalized blood pressure, endothelial dysfunction, and the contractile responses to ET-<em>1</em> and NA. Valsartan also normalized serum 8-isoprostaglandin F(2alpha) levels, renal XOR activity, and, to a degree, NO(x) excretion. Thus, overproduction of Ang II in dTGR induces pronounced endothelial dysfunction, whereas the sensitivity of vascular smooth muscle cells to nitric oxide is unaltered. Ang II-induced endothelial dysfunction is associated with increased oxidative stress and vascular xanthine oxidase activity.

Actions of <em>angiotensin</em>-(<em>1</em>-<em>7</em>) [Ang-(<em>1</em>-<em>7</em>)], a heptapeptide of the renin-<em>angiotensin</em> system, in the periphery are mediated, at least in part, by activation of nitric oxide (NO) synthase (NOS) and generation NO(·). Studies of the central nervous system have shown that NO(·) acts as a sympathoinhibitory molecule and thus may play a protective role in neurocardiovascular diseases associated with sympathoexcitation, such as hypertension and heart failure. However, the contribution of NO in the intraneuronal signaling pathway of Ang-(<em>1</em>-<em>7</em>) and the subsequent modulation of neuronal activity remains unclear. Here, we tested the hypothesis that neuronal NOS (nNOS)-derived NO(·) mediates changes in neuronal activity following Ang-(<em>1</em>-<em>7</em>) stimulation. For these studies, we used differentiated catecholaminergic (CATH.a) neurons, which we show express the Ang-(<em>1</em>-<em>7</em>) receptor (Mas R) and nNOS. Stimulation of CATH.a neurons with Ang-(<em>1</em>-<em>7</em>) (<em>1</em>00 nM) increased intracellular NO levels, as measured by 4-amino-5-methylamino-2',<em>7</em>'-difluorofluorescein diacetate (DAF-FM) fluorescence and confocal microscopy. This response was significantly attenuated in neurons pretreated with the Mas R antagonist (A-<em>7</em><em>7</em>9), a nonspecific NOS inhibitor (nitro-L-arginine methyl ester), or an nNOS inhibitor (S-methyl-L-thiocitrulline, SMTC), but not by endothelial NOS (eNOS) or inhibitory NOS (iNOS) inhibition {L-N-5-(<em>1</em>-iminoethyl)ornithine (L-NIO) and <em>1</em>400W, respectively}. To examine the effect of Ang-(<em>1</em>-<em>7</em>)-NO(·) signaling on neuronal activity, we recorded voltage-gated outward K(+) current (I(Kv)) in CATH.a neurons using the whole cell configuration of the patch-clamp technique. Ang-(<em>1</em>-<em>7</em>) significantly increased I(Kv), and this response was inhibited by A-<em>7</em><em>7</em>9 or S-methyl-L-thiocitrulline, but not L-NIO or <em>1</em>400W. These findings indicate that Ang-(<em>1</em>-<em>7</em>) is capable of increasing nNOS-derived NO(·) levels, which in turn, activates hyperpolarizing I(Kv) in catecholaminergic neurons.