The Gq-RhoA-Rho kinase pathway, activated by neurohormonal factors such as <em>angiotensin</em> II (Ang II), has been proposed to be one of the important signaling pathways involved in the progression of left ventricular (LV) hypertrophy to heart failure. We tested the hypothesis that chronic inhibition of Rho kinase prevents this process. Heart failure was induced in Dahl salt-sensitive (DS) rats fed an 8% NaCl diet from 8 until <em>1</em><em>7</em> weeks of age. Y-2<em>7</em>632 (5 mg/kg per day), a selective Rho kinase inhibitor, was applied orally to DS rats starting at <em>1</em>0 weeks of age for <em>7</em> weeks (DS/Y+). DS rats without Y-2<em>7</em>632 (DS/Y-) and Dahl salt-resistant (DR) rats fed the 8% NaCl diet were regarded as non-therapeutic and normotensive controls, respectively. At <em>1</em><em>7</em> weeks of age, there was no significant difference in the blood pressure of DS/Y- and DS/Y+ rats. DS/Y- rats exhibited: (<em>1</em>) increases in LV mass, cross-sectional area (CSA) of cardiomyocytes, and interstitial fibrosis; (2) contractile dysfunction, i.e. decreases in LV ejection fraction and % fractional shortening, and prolongation of time to peak tension as well as to 50% relaxation in the twitch contraction of isolated papillary muscle; and (3) increases in the protein expression of Galphaq and Rho kinase in the myocardial membrane fraction. In DS/Y+ rats, the degree of myocardial hypertrophy was significantly inhibited in association with improved contractile function, without a decrease in the degree of interstitial fibrosis. Our results suggest the possibility that the Gq-Rho kinase pathway plays an important role in the process of hypertension-induced LV hypertrophy leading to contractile dysfunction.

Rats harboring the human renin and <em>angiotensin</em>ogen genes (dTGR) feature <em>angiotensin</em> (ANG) II/hypertension-induced cardiac damage and die suddenly between wk <em>7</em> and 8. We observed by electrocardiogram (ECG) telemetry that ventricular tachycardia (VT) is a common terminal event in these animals. Our aim was to investigate electrical remodeling. We used ECG telemetry, noninvasive cardiac magnetic field mapping (CMFM) at wk 5 and <em>7</em>, and performed in vivo programmed electrical stimulation at wk <em>7</em>. We also investigated whether or not losartan (Los; 30 mg x kg(-<em>1</em>) x day(-<em>1</em>)) would prevent electrical remodeling. Cardiac hypertrophy and systolic blood pressure progressively increased in dTGR compared with Sprague-Dawley (SD) controls. Already by wk 5, untreated dTGR showed increased perivascular and interstitial fibrosis, connective tissue growth factor expression, and monocyte infiltration compared with SD rats, differences that progressed through time. Left-ventricular mRNA expression of potassium channel subunit Kv4.3 and gap-junction protein connexin 43 were significantly reduced in dTGR compared with Los-treated dTGR and SD. CMFM showed that depolarization and repolarization were prolonged and inhomogeneous. Los ameliorated all disturbances. VT could be induced in 88% of dTGR but only in 33% of Los-treated dTGR and could not be induced in SD. Untreated dTGR show electrical remodeling and probably die from VT. Los treatment reduces myocardial remodeling and predisposition to arrhythmias. ANG II target organ damage induces VT.

Loss of <em>angiotensin</em> (Ang)-converting enzyme 2 (ACE2) and inability to metabolize Ang II to Ang <em>1</em>-<em>7</em> perpetuate the actions of Ang II after biomechanical stress and exacerbate early adverse myocardial remodeling. Ang receptor blockers are known to antagonize the effect of Ang II by blocking Ang II type <em>1</em> receptor (AT(<em>1</em>)R) and also by upregulating the ACE2 expression. We directly compare the benefits of AT(<em>1</em>)R blockade versus enhancing Ang <em>1</em>-<em>7</em> action in pressure-overload-induced heart failure in ACE2 knockout mice. AT(<em>1</em>)R blockade and Ang <em>1</em>-<em>7</em> both resulted in marked recovery of systolic dysfunction in pressure-overloaded ACE2-null mice. Similarly, both therapies attenuated the increase in NADPH oxidase activation by downregulating the expression of Nox2 and p4<em>7</em>(phox) subunits and also by limiting the p4<em>7</em>(phox) phosphorylation. Biomechanical stress-induced increase in protein kinase C-α expression and phosphorylation of extracellular signal-regulated kinase <em>1</em>/2, signal transducer and activator of transcription 3, Akt, and glycogen synthase kinase 3β were normalized by irbesartan and Ang <em>1</em>-<em>7</em>. Ang receptor blocker and Ang <em>1</em>-<em>7</em> effectively reduced matrix metalloproteinase 2 activation and matrix metalloproteinase 9 levels. Ang II-mediated cellular effects in cultured adult cardiomyocytes and cardiofibrolasts isolated from pressure-overloaded ACE2-null hearts were inhibited to similar degree by AT(<em>1</em>)R blockade and stimulation with Ang <em>1</em>-<em>7</em>. Thus, treatment with the AT(<em>1</em>)R blocker irbesartan and Ang <em>1</em>-<em>7</em> prevented the cardiac hypertrophy and improved cardiac remodeling in pressure-overloaded ACE2-null mice by suppressing NADPH oxidase and normalizing pathological signaling pathways.

<strong class="sub-title"> Introduction: </strong> Obese patients have an increased risk of COVID-<em>1</em>9 critical illness leading to ICU admission or death compared to normal weight individuals. SARS-CoV-2 binding to <em>angiotensin</em>-converting enzyme 2 (ACE2) receptor is a critical step mediate virus entry into target cells. Articles have alluded that the level of ACE2 gene expression in adipose tissue is higher than lung tissue, but a PubMed search found no results in articles to demonstrate this. The aim of this study was to investigate ACE2 gene expression in adipose tissue and lung tissue using a public database.

Material and methods: A search of a public gene expression database to investigate ACE2 gene expression in human tissues.

Results: ACE2 gene expression was present in both visceral and subcutaneous adipose tissues. The gene expression profile demonstrated that ACE2 gene expression was higher in human visceral and subcutaneous adipose tissues than human lung tissue.

<strong class="sub-title"> Conclusion: </strong> This study demonstrates that ACE2 gene expression is higher in visceral and subcutaneous adipose tissue than that in lung tissue, a major target tissue affected by SARS-CoV-2 infection. This suggests a mechanism by which excess adiposity may drive greater infection severity in patients with COVID-<em>1</em>9.

<strong class="sub-title"> Keywords: </strong> ACE, <em>angiotensin</em> converting enzyme; ACE2, <em>angiotensin</em> converting enzyme-2; AT(<em>1</em>–<em>7</em>), <em>angiotensin</em> (<em>1</em>–<em>7</em>); AT<em>1</em>, <em>angiotensin</em> <em>1</em>; AT2, <em>angiotensin</em> 2; Adipose tissue; Angiotensin converting enzyme 2 receptor; COVID-<em>1</em>9; COVID-<em>1</em>9, Coronavirus disease 20<em>1</em>9; Coronavirus; SARS CoV, severe acute respiratory syndrome coronavirus; SARS CoV-2, severe acute respiratory syndrome coronavirus-2; Severe acute respiratory syndrome coronavirus 2.

BACKGROUND

Vitamin D has shown efficacy in the reduction of proteinuria in patients with chronic kidney disease. This study aimed to determine the effect of calcitriol on urinary protein excretion in patients with immunoglobulin A (IgA) nephropathy.

METHODS

Open-label, non-placebo-controlled, randomized study.

METHODS

50 patients with IgA nephropathy were enrolled. The main criterion for inclusion was urinary protein excretion >0.8 g/d after renin-angiotensin system-inhibitor treatment for at least 3 months.

METHODS

Patients were randomly assigned (1:1) to receive 2 doses (0.5 μg) of calcitriol per week or no treatment for 48 weeks.

RESULTS

The primary end point was to compare change in 24-hour urinary protein excretion from baseline to last measurement during treatment.

METHODS

Every 8 weeks, there was measurement of 24-hour urinary protein excretion, serum calcium, serum phosphorus, serum creatinine, and intact parathyroid hormone.

RESULTS

Measurement of the primary end point showed changes in urinary protein excretion of +21% (from 1.29 to 1.58 g/24 h; 95% CI, -9% to +52%) in the control group and -19% (from 1.60 to 1.30 g/24 h; 95% CI, -42% to +4%) in the calcitriol-treated group. There was a significant decrease in proteinuria in the calcitriol-treated group compared with the control group (difference between groups, 41%; 95% CI, 5%-79%; P = 0.03). The secondary end point of achieving at least a 15% decrease in proteinuria was attained by 7 of 24 (29%) controls and 17 of 26 (65%) of those treated with calcitriol (P = 0.02). No significant differences were observed in decrease in estimated glomerular filtration rate and change in blood pressure between the 2 groups. The incidence of recorded adverse events was similar between the 2 groups.

CONCLUSIONS

Small and non-placebo-controlled study.

CONCLUSIONS

The addition of calcitriol to a renin-angiotensin system inhibitor resulted in a safe decrease in proteinuria in patients with IgA nephropathy.

Patients with cardiovascular disease and, namely, heart failure are more susceptible to coronavirus disease 20<em>1</em>9 (COVID-<em>1</em>9) and have a more severe clinical course once infected. Heart failure and myocardial damage, shown by increased troponin plasma levels, occur in at least <em>1</em>0% of patients hospitalized for COVID-<em>1</em>9 with higher percentages, 25%-35% or more, when patients critically ill or with concomitant cardiac disease are considered. Myocardial injury may be elicited by multiple mechanisms, including those occurring with all severe infections, such as fever, tachycardia, adrenergic stimulation, as well as those caused by the exaggerated inflammatory response, endotheliitis and, in some cases, myocarditis that have been shown in patients with COVID-<em>1</em>9. A key role may be that of the renin-<em>angiotensin</em>-aldosterone system. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects human cells binding to <em>angiotensin</em>-converting-enzyme 2 (ACE2), an enzyme responsible of the cleavage of <em>angiotensin</em> II into <em>angiotensin</em> <em>1</em>-<em>7</em>, which has vasodilating and anti-inflammatory effects. Virus-mediated downregulation of ACE2 may increase <em>angiotensin</em> II stimulation and contribute to the deleterious hyper-inflammatory reaction of COVID-<em>1</em>9. On the other hand, ACE2 may be upregulated in patients with cardiac disease and treated with ACE inhibitors or <em>angiotensin</em> receptor blockers. ACE2 upregulation may increase the susceptibility to COVID-<em>1</em>9 but may be also protective versus <em>angiotensin</em> II mediated vasoconstriction and inflammatory activation. Recent data show the lack of untoward effects of ACE inhibitors or <em>angiotensin</em> receptor blockers for COVID-<em>1</em>9 infection and severity. Prospective trials are needed to ascertain whether these drugs may have protective effects. This article is protected by copyright. All rights reserved.

Myocardial stretch elicits a rapid increase in developed force, which is mainly caused by an increase in myofilament calcium sensitivity (Frank-Starling mechanism). Over the ensuing <em>1</em>0-<em>1</em>5 min, a second gradual increase in force takes place. This slow force response to stretch is known to be the result of an increase in the calcium transient amplitude and constitutes the in vitro equivalent of the Anrep effect described <em>1</em>00 years ago in the intact heart. In the present review, we will update and discuss what is known about the Anrep effect as the mechanical counterpart of autocrine/paracrine mechanisms involved in its genesis. The chain of events triggered by myocardial stretch comprises <em>1</em>) release of <em>angiotensin</em> II, 2) release of endothelin, 3) activation of the mineralocorticoid receptor, 4) transactivation of the epidermal growth factor receptor, 5) increased formation of mitochondria reactive oxygen species, 6) activation of redox-sensitive kinases upstream myocardial Na(+)/H(+) exchanger (NHE<em>1</em>), <em>7</em>) NHE<em>1</em> activation, 8) increase in intracellular Na(+) concentration, and 9) increase in Ca(2+) transient amplitude through the Na(+)/Ca(2+) exchanger. We will present the experimental evidence supporting each of the signaling steps leading to the Anrep effect and its blunting by silencing NHE<em>1</em> expression with a specific small hairpin interference RNA injected into the ventricular wall.

OBJECTIVE

<em>Angiotensin</em>-(<em>1</em>-<em>7</em>) [Ang-(<em>1</em>-<em>7</em>)] is an endogenous peptide hormone of the renin-<em>angiotensin</em> system with antiproliferative and antiangiogenic properties. The primary objective of this study was to establish the recommended phase II dose of Ang-(<em>1</em>-<em>7</em>) for treating patients with advanced cancer. Secondary objectives were to assess toxicities, pharmacokinetics, clinical activity, and plasma biomarkers.

METHODS

Patients with advanced solid tumors refractory to standard therapy were treated with escalating doses of Ang-(<em>1</em>-<em>7</em>) in cohorts of three patients. Ang-(<em>1</em>-<em>7</em>) was administered by s.c. injection once daily for 5 days on a 3-week cycle. Tumor measurements were done every two cycles and treatment was continued until disease progression or unacceptable toxicity.

RESULTS

Eighteen patients were enrolled. Dose-limiting toxicities encountered at the <em>7</em>00 microg/kg dose included stroke (grade 4) and reversible cranial neuropathy (grade 3). Other toxicities were generally mild. One patient developed a <em>1</em>9% reduction in tumor measurements. Three additional patients showed clinical benefit with stabilization of disease lasting more than 3 months. On day <em>1</em>, Ang-(<em>1</em>-<em>7</em>) administration led to a decrease in plasma placental growth factor (PlGF) levels in patients with clinical benefit (P = 0.04) but not in patients without clinical benefit (P = 0.25). On day 5, PlGF levels remained lower in patients with clinical benefit compared with patients without clinical benefit (P = 0.04).

CONCLUSIONS

Ang-(<em>1</em>-<em>7</em>) is a first-in-class antiangiogenic drug with activity for treating cancer that is linked to reduction of plasma PlGF levels. The recommended phase II dose is 400 microg/kg for this administration schedule.

BACKGROUND

The renal actions of brain natriuretic peptide (BNP) in congestive heart failure (CHF) are associated with increased diuresis and natriuresis, preserved glomerular filtration rate (GFR), and lack of activation of the renin-angiotensin-aldosterone system (RAAS). In contrast, diuretic-induced natriuresis may be associated with reduced GFR and RAAS activation. The objective of this study was to test the hypothesis that exogenous BNP enhances the renal diuretic and natriuretic actions of furosemide (Fs) and retards the activation of aldosterone in a model of CHF.

RESULTS

CHF was produced in 2 groups of dogs by ventricular pacing. One group received continuous (90-minute) intravenous Fs (1 mg x kg(-1) x h(-1)). A second group (Fs+BNP) received 45-minute intravenous coinfusion of Fs (1 mg x kg(-1) x h(-1)) and low-dose (2 pmol x kg(-1) x min(-1)) BNP followed by 45-minute coinfusion of Fs (1 mg x kg(-1) x h(-1)) and high-dose (10 pmol x kg(-1) x min(-1)) BNP. Fs increased urinary flow, but the effect of Fs+BNP was greater. Similarly, urinary sodium excretion was higher in the Fs+BNP group. Although GFR tended to decrease in the Fs group, it increased in the Fs+BNP group (35+/-3 to 56+/-4*) (* indicates P<0.05 versus baseline) (P<0.0001 between groups). Plasma aldosterone increased with Fs (41+/-10 to 100+/-11* ng/dL) but was attenuated in the Fs+BNP group (44+/-11 to 54+/-9 ng/dL low-dose and to 47+/-7 ng/dL high-dose) (P=0.0007 between groups).

CONCLUSIONS

Fs+BNP has more profound diuretic and natriuretic responses than Fs alone and also increases GFR without activation of aldosterone. Coadministration of BNP and loop diuretic is effective in maximizing natriuresis and diuresis while preserving renal function and inhibiting activation of aldosterone.

The renin-<em>angiotensin</em> system (RAS) is a key regulator of vascular resistance, sodium and water homeostasis and the response to tissue injury. Historically, <em>angiotensin</em> II (Ang II) was thought to be the primary effector peptide of this system. Ang II is produced predominantly by the effect of <em>angiotensin</em> converting enzyme (ACE) on <em>angiotensin</em> I (Ang I). Ang II acts mainly through the <em>angiotensin</em> II type-<em>1</em> receptor (AT(<em>1</em>)) and, together with ACE, these components represent the 'classical' axis of the RAS. Drug therapies targeting the RAS by inhibiting Ang II formation (ACE inhibitors) or binding to its receptor (<em>angiotensin</em> receptor blockers) are now in widespread clinical use and have been shown to reduce tissue injury and fibrosis in cardiac and renal disease independently of their effects on blood pressure. In 2000, two groups using different methodologies identified a homolog of ACE, called ACE2, which cleaves Ang II to form the biologically active heptapeptide, Ang-(<em>1</em>-<em>7</em>). Conceptually, ACE2, Ang-(<em>1</em>-<em>7</em>), and its putative receptor, the mas receptor represent an 'alternative' axis of the RAS capable of opposing the often deleterious actions of Ang II. Interestingly, ACE inhibitors and <em>angiotensin</em> receptor blockers increase Ang-(<em>1</em>-<em>7</em>) production and it has been proposed that some of the beneficial effects of these drugs are mediated through upregulation of Ang-(<em>1</em>-<em>7</em>) rather than inhibition of Ang II production or receptor binding. The present review focuses on the novel components and pathways of the RAS with particular reference to their potential contribution towards the pathophysiology of liver disease.

The goal of the present study was to test the hypothesis that the CuZn isoform of superoxide dismutase (CuZnSOD) protects against <em>angiotensin</em> II (Ang II)-induced endothelial dysfunction. Vascular responses of carotid arteries from control, CuZnSOD-deficient (CuZnSOD(+/-)), and CuZnSOD transgenic mice were examined in vitro after overnight incubation with either vehicle or Ang II (<em>1</em> or <em>1</em>0 nmol/L). In control mice, acetylcholine produced concentration-dependent relaxation that was not affected by <em>1</em> nmol/L Ang II. In contrast, relaxation to acetylcholine in arteries from CuZnSOD+/- mice was markedly and selectively attenuated after incubation with <em>1</em> nmol/L Ang II (eg, <em>1</em>00 micromol/L acetylcholine produced 93+/-6% and 44+/-<em>1</em>5% relaxation in vehicle- and Ang II-treated arteries, respectively). A higher concentration of Ang II (<em>1</em>0 nmol/L) selectively impaired relaxation to acetylcholine in arteries from control mice (eg, <em>1</em>00 micromol/L acetylcholine produced 96+/-4% and 45+/-<em>7</em>% relaxation in vehicle- and Ang II-treated vessels, respectively). In contrast, <em>1</em>0 nmol/L Ang II had no effect on responses to acetylcholine in carotid arteries from CuZnSOD transgenic mice (or in control mice treated with the superoxide scavenger Tiron [<em>1</em> mmol/L]). Superoxide levels in control mice were higher in aorta treated with Ang II than with vehicle and were markedly reduced in CuZnSOD transgenic mice. These findings provide the first direct evidence that CuZnSOD limits Ang II-mediated impairment of endothelial function and that loss of <em>1</em> copy of the CuZnSOD gene is sufficient to enhance Ang II-induced vascular dysfunction.

<em>1</em>. Prolonged exposure of the brain of the normal Na-replete rat to <em>angiotensin</em> II produced a marked and persistent Na appetite. In a first series of experiments, short-term, repeated systemic injections of isoprenaline or renin (both of which raise circulating <em>angiotensin</em> levels), and repeated intracranial injections of <em>angiotensin</em> II evoked increased ingestion of 2 . <em>7</em>% NaCl. In the second series of experiments, continuous infusions of <em>angiotensin</em> II directly into the brain evoked extremely large intakes of 3% NaCl. 2. In addition to large intakes of hypertonic NaCl some rats drank daily volumes of water that exceeded their body weight. 3. Not only did the animals drink large volumes of 3% NaCl some rats drank daily volumes of water that exceeded their body weight. 3. Not only did the animals drink large volumes of 3% NaCl during continuous <em>angiotensin</em> II infusion, but after termination of the infusion they continued to ingest NaCl at a rate comparable to that of the adrenalectomized rat. In most of the animals the persistent NaCl intake diminished over several days, but other animals continued to drink NaCl for as long as their intake was measured (up to <em>7</em> months). 4. The response to continuous infusion of <em>angiotensin</em> II was dose-dependent. Both water and 3% NaCl intake increased over a dose range of 6 ng h-<em>1</em> to 6000 ng h-<em>1</em>. The persistence of the sodium appetitite was also dose-dependent across the same range of doses. 5. <em>Angiotensin</em>-induced salt appetite is specific for Na. Animals did not drink 0 . 5 M-NH4Cl and only occasionally drank minimal amounts of 0 . 5 M-KCl during continuous infusion. 6. The large water turnover was not responsible for the Na appetite. Rats given access to 3% NaCl only during infusion of <em>angiotensin</em> copiously. Animals that were not infused but were given saccharine-flavoured water in order to increase their water intakes did not drink 3% NaCl offered at the same time even though fluid intake was high. Rats that did not receive intracranial infusions but were infused intragastrically with volumes of water equal to or exceeding the amounts that were drunk during <em>angiotensin</em> infusion did not drink the 3% NaCl but did drink some water. <em>7</em>. Records of the drinking by rats infused with <em>angiotensin</em> show that firstly the onset of drinking after the start of <em>angiotensin</em> infusion varied from animal to animal, secondly, NaCl drinking was not temporally linked to water intake, although this was observed occasionally, and thirdly, most of the drinking occurred during the night although <em>angiotensin</em> was infused continuously throughtout the nychthemeron. 8. Therefore, increases in <em>angiotensin</em> levels, probably with other factors such as increased levels of aldosterone or ACTH, result in Na appetite. The hormonal changes may alter the animals' preception of salt making it more acceptable. By means that are not yet understood the increased accceptability of salt persists after the termination of <em>angiotensin</em> infusion.

<em>1</em>. Contractile responses of rabbit aortic rings elicited by KCl-depolarization, <em>angiotensin</em> II (AII), 5-hydroxytryptamine (5-HT) and noradrenaline (NA) have been investigated in the presence of cromakalim (BRL 349<em>1</em>5) and isradipine (PN 200-<em>1</em><em>1</em>0). 2. Above <em>1</em>0(-6)M, cromakalim inhibited contractile responses to low (less than or equal to 32 mM) but not to higher KCl concentrations. The 5-HT and AII concentration-response curves were antagonized noncompetitively by cromakalim (<em>1</em>0(-<em>7</em>)-<em>1</em>0(-5)M) and the maximal responses were inhibited by 40 and 55%, respectively. 3. Isradipine caused less inhibition of AII and 5-HT contractile responses than cromakalim, and in the presence of isradipine (<em>1</em>0(-<em>7</em>)M), cromakalim was still able to antagonize further the contractions to AII in this vessel. 4. NA-induced contractions were relatively insensitive to inhibition by cromakalim and isradipine, both drugs causing a small rightward shift of the NA concentration-response curve. This result suggests that NA utilizes different Ca2+ pools from those involved in AII- and 5-HT-induced contractions of this vessel. 5. The sustained (tonic) part of the NA response was inhibited in a concentration-dependent manner by cromakalim (<em>1</em>0(-<em>7</em>)-<em>1</em>0(-5)M), but not by isradipine. 6. In aortic rings partially depolarized with 3.5 x <em>1</em>0(-2)M KCl, the ability of cromakalim, but not of sodium nitroprusside, atriopeptin III or hydralazine, to inhibit AII- and tonic NA-induced contractions was abolished. <em>7</em>. Antivasoconstrictor activity of cromakalim on the rabbit aorta appears to involve factors in addition to an indirect inhibition of Ca2+ entry through dihydropyridine-sensitive Ca2+ channels. 8. The ability of cromakalim to open K+ channels and thereby modify the membrane potential would appear to underlie these antivasoconstrictor effects. This mechanism of action of cromakalim clearly differs from that of other vasodilators such as sodium nitroprusside and hydralazine.

Acute administration of the <em>angiotensin</em>-converting enzyme (ACE) inhibitor captopril enhances insulin-stimulated glucose transport activity in skeletal muscle of the insulin-resistant obese Zucker rat. The present study was designed to assess whether this effect is mediated by an increase in the nonapeptide bradykinin (BK), by a decrease in action of ANG II, or both. Obese Zucker rats (8-9 wk old) were treated for 2 h with either captopril (50 mg/kg orally), bradykinin (200 micrograms/kg ip), or the ANG II receptor (AT(<em>1</em>) subtype) antagonist eprosartan (20 mg/kg orally). Captopril treatment enhanced in vitro insulin-stimulated (2 mU/ml) 2-deoxyglucose uptake in the epitrochlearis muscle by 22% (25<em>1</em> +/- <em>7</em> vs. 205 +/- 9 pmol. mg(-<em>1</em>). 20 min(-<em>1</em>); P < 0.05), whereas BK treatment enhanced this variable by <em>1</em>8% (249 +/- <em>1</em>5 vs. 2<em>1</em>5 +/- <em>7</em> pmol. mg(-<em>1</em>). 20 min(-<em>1</em>); P < 0.05). Eprosartan did not significantly modify insulin action. The BK-mediated increase in insulin action was completely abolished by pretreatment with either the specific BK-B(2) receptor antagonist HOE <em>1</em>40 (200 micrograms/kg ip) or the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (50 mg/kg ip). Collectively, these results indicate that the modulation of insulin action by BK likely underlies the metabolic effects of ACE inhibitors in the insulin-resistant obese Zucker rat. Moreover, this modulation of insulin action by BK is likely mediated through B(2) receptors and by an increase in nitric oxide production and/or action in skeletal muscle tissue.

Fischer-344 (F344) rats exhibit proteinuria and insulin resistance in the absence of hypertension as they age. We determined the effects of long-term (<em>1</em> yr) treatment with the <em>angiotensin</em> (ANG) II type <em>1</em> (AT(<em>1</em>)) receptor blocker L-<em>1</em>58,809 on plasma and urinary ANG peptide levels, systolic blood pressure (SBP), and indexes of glucose metabolism in <em>1</em>5-mo-old male F344 rats. Young rats at 3 mo of age (n = 8) were compared with two separate groups of older rats: one control group (n = <em>7</em>) and one group treated with L-<em>1</em>58,809 (n = 6) orally (20 mg/l) for <em>1</em> yr. SBP was not different between control and treated rats but was higher in young rats. Serum leptin, insulin, and glucose levels were comparable between treated and young rats, whereas controls had higher glucose and leptin with a similar trend for insulin. Plasma ANG I and ANG II were higher in treated than untreated young or older rats, as evidence of effective AT(<em>1</em>) receptor blockade. Urinary ANG II and ANG-(<em>1</em>-<em>7</em>) were higher in controls compared with young animals, and treated rats failed to show age-related increases. Protein excretion was markedly lower in treated and young rats compared with control rats (young: 8 +/- 2 mg/day vs. control: <em>1</em>29 +/- 5<em>1</em> mg/day vs. treated: 9 +/- 3 mg/day, P < 0.05). Long-term AT(<em>1</em>) receptor blockade improves metabolic parameters and provides renoprotection. Differential regulation of systemic and intrarenal (urinary) ANG systems occurs during blockade, and suppression of the intrarenal system may contribute to reduced proteinuria. Thus, insulin resistance, renal injury, and activation of the intrarenal ANG system during early aging in normotensive animals can be averted by renin-ANG system blockade.

BACKGROUND

The role of lipid-lowering treatments in renoprotection for patients with diabetes is debated. We studied the renal effects of two statins in patients with diabetes who had proteinuria.

METHODS

PLANET I was a randomised, double-blind, parallel-group trial done in <em>1</em>47 research centres in Argentina, Brazil, Bulgaria, Canada, Denmark, France, Hungary, Italy, Mexico, Romania, and the USA. We enrolled patients with type <em>1</em> or type 2 diabetes aged <em>1</em>8 years or older with proteinuria (urine protein:creatinine ratio [UPCR] 500-5000 mg/g) and taking stable <em>angiotensin</em>-converting enzyme inhibitors, <em>angiotensin</em> receptor blockers, or both. We randomly assigned participants to atorvastatin 80 mg, rosuvastatin <em>1</em>0 mg, or rosuvastatin 40 mg for 52 weeks. The primary endpoint was change from baseline to week 52 of mean UPCR in each treatment group. The study is registered with ClinicalTrials.gov, number NCT00296374.

RESULTS

We enrolled 353 patients: <em>1</em><em>1</em>8 were assigned to rosuvastatin <em>1</em>0 mg, <em>1</em>24 to rosuvastatin 40 mg, and <em>1</em><em>1</em><em>1</em> to atorvastatin 80 mg; of these, 325 were included in the intention-to-treat population. UPCR baseline:week 52 ratio was 0·87 (95% CI 0·77-0·99; p=0·033) with atorvastatin 80 mg, <em>1</em>·02 (0·88-<em>1</em>·<em>1</em>8; p=0·83) with rosuvastatin <em>1</em>0 mg, and 0·96 (0·83-<em>1</em>·<em>1</em><em>1</em>; p=0·53) with rosuvastatin 40 mg. In a post-hoc analysis to compare statins, we combined data from PLANET I with those from PLANET II (a similar randomised parallel study of 237 patients with proteinuria but without diabetes; registered with ClinicalTrials.gov, NCT00296400). In this analysis, atorvastatin 80 mg lowered UPCR significantly more than did rosuvastatin <em>1</em>0 mg (-<em>1</em>5·6%, 95% CI -28·3 to -0·5; p=0·043) and rosuvastatin 40 mg (-<em>1</em>8·2%, -30·2 to -4·2; p=0·0<em>1</em>3). Adverse events occurred in 69 (60%) of <em>1</em><em>1</em>6 patients in the rosuvastatin <em>1</em>0 mg group versus 79 (64%) of <em>1</em>23 patients in the rosuvastatin 40 mg group versus 63 (57%) of <em>1</em><em>1</em>0 patients in the atorvastatin 80 mg group; renal events occurred in nine (7·8%) versus <em>1</em>2 (9·8%) versus five (4·5%).

CONCLUSIONS

Despite high-dose rosuvastatin lowering plasma lipid concentrations to a greater extent than did high-dose atorvastatin, atorvastatin seems to have more renoprotective effects for the studied chronic kidney disease population.

BACKGROUND

AstraZeneca.

OBJECTIVE

During atrial fibrillation, arterial hypertension and systolic or diastolic heart failure, atrial myocytes are exposed to increased baseline stretch. Atrial stretch has been shown to induce cellular hypertrophy and extracellular matrix remodeling (ECM) via <em>angiotensin</em>-II dependent pathways and the matrix metalloproteinases system (MMPs). We hypothesized that atrial myocytes exposed to static stretch may increase their ECM remodeling activity via up-regulation of MMP-2/-9. We then tested the hypothesis that the membrane bound <em>angiotensin</em>-II type <em>1</em> (AT<em>1</em>) receptor and the intracellular calcineurin (Cn)-NFAT signaling pathway are potential mediators of stretch-induced MMP alterations, since Cn-NFAT is one important contributor to myocyte hypertrophy.

RESULTS

Neonatal rat atrial myocytes (NRAM) were cultured under conditions of static stretch by 2<em>1</em>%. The differential effects of selective AT<em>1</em> receptor blockade by losartan, Cn blockade by Cyclosporine-A (CsA) or NFAT inhibition by <em>1</em><em>1</em>R-VIVIT (VIV), were analyzed. Stretch resulted in a significant up-regulation of active-MMP-2/-9 protein amount (active-MMP-2 ng/microg: control 8.95 +/- 0.64 vs. stretch <em>1</em>3.<em>1</em><em>1</em> +/- 0.74 / active-MMP-9 ng/microg: control <em>1</em>.45 +/- 0.<em>1</em>8 vs. stretch <em>1</em>.94 +/- 0.2<em>1</em>, all n = 5) and enzyme activity (MMP-2 in %: control <em>1</em> +/- 0.0 vs. stretch <em>1</em>.87 +/- 0.25, n = 7) associated with a significant increase of the membrane-type-<em>1</em>-MMP (MT<em>1</em>-MMP) protein expression (MT<em>1</em>-MMP in %: control <em>1</em> +/- 0.0 vs. stretch 2.<em>1</em>7 +/- 0.2<em>1</em>, n = 8). These observations were accompanied by an activation of the Cn-NFAT pathway (Cn-activity in nmol PO(4) release/20 microg protein/30 min: control 0.37 +/- 0.08 vs. stretch 0.65 +/- 0.09, n = 3 / NFATc<em>1</em>-DNA binding activity in %: control <em>1</em> +/- 0.0 vs. stretch <em>1</em>.53 +/- 0.<em>1</em>7, n = 3). Losartan, CsA or VIV abolished stretch-induced alterations in MMP-2/-9 and MT<em>1</em>-MMP expression and enzyme activity by normalizing the Cn-activity and the DNA binding activity of NFATc<em>1</em>.

CONCLUSIONS

Our results present new insights in molecular mechanisms of ECM remodeling activity of atrial myocytes exposed to static stretch. The AT<em>1</em>-Cn-NFAT pathway is a potential mediator of MMP activation.

<AbstractText>We evaluated the influence of the renin-<em>angiotensin</em> system (RAS) on intestinal inflammation and fibrosis.</AbstractText><AbstractText>Cultured human colonic myofibroblast proliferation and collagen secretion were assessed following treatment with <em>angiotensin</em> (Ang) II and Ang (<em>1</em>-<em>7</em>), their receptor antagonists candesartan and A<em>7</em><em>7</em>9, and the ACE inhibitor captopril. Circulating and intestinal RAS components were evaluated in patients with and without IBD. Disease outcomes in patients with IBD treated with ACE inhibitors and <em>angiotensin</em> receptor blockers (ARBs) were assessed in retrospective studies.</AbstractText><AbstractText>Human colonic myofibroblast proliferation was reduced by Ang (<em>1</em>-<em>7</em>) in a dose-dependent manner (p<0.05). Ang II marginally but not significantly increased proliferation, an effect reversed by candesartan (p<0.00<em>1</em>). Colonic myofibroblast collagen secretion was reduced by Ang (<em>1</em>-<em>7</em>) (p<0.05) and captopril (p<0.00<em>1</em>), and was increased by Ang II (p<0.00<em>1</em>). Patients with IBD had higher circulating renin (mean 25.4 vs <em>1</em>8.6 mIU/L, p=0.026) and ACE2:ACE ratio (mean 0.92 vs 0.69, p=0.0<em>1</em>5) than controls without IBD. RAS gene transcripts and peptides were identified in healthy and diseased bowels. Colonic mucosal Masson's trichrome staining correlated with Ang II (r=0.346, p=0.0<em>1</em>0) and inversely with ACE2 activity (r=-0.3<em>7</em>3, p=0.006). Patients with IBD who required surgery (<em>1</em>/3<em>7</em> vs <em>1</em>2/<em>7</em>5, p=0.034) and hospitalisation (0/34 vs 8/68, p=0.049) over 2 years were less often treated with ACE inhibitors and ARBs than patients not requiring surgery or hospitalisation.</AbstractText><AbstractText>The RAS mediates fibrosis in human cell cultures, is expressed in the intestine and perturbed in intestinal inflammation, and agents targeting this system are associated with improved disease outcomes.</AbstractText>

Classically, <em>7</em> transmembrane receptors transduce extracellular signals by coupling to heterotrimeric G proteins, although recent in vitro studies have clearly demonstrated that they can also signal via G protein-independent mechanisms. However, the physiologic consequences of this unconventional signaling, particularly in vivo, have not been explored. In this issue of the JCI, Zhai et al. demonstrate in vivo effects of G protein-independent signaling by the <em>angiotensin</em> II type <em>1</em> receptor (AT<em>1</em>R) (see the related article beginning on page 3045). In studies of the mouse heart, they compare the physiologic and biochemical consequences of transgenic cardiac-specific overexpression of a mutant AT<em>1</em>R incapable of G protein coupling with those of a wild-type receptor. Their results not only provide the first glimpse of the physiologic effects of this newly appreciated mode of signaling but also provide important and previously unappreciated clues as to the underlying molecular mechanisms.

The Ang II (<em>Angiotensin</em> II)-<em>Angiotensin</em>-(<em>1</em>-<em>7</em>) axis of the Renin <em>Angiotensin</em> System encompasses 3 enzymes that form <em>Angiotensin</em>-(<em>1</em>-<em>7</em>) [Ang-(<em>1</em>-<em>7</em>)] directly from Ang II: ACE2 (<em>angiotensin</em>-converting enzyme 2), PRCP (prolylcarboxypeptidase), and POP (prolyloligopeptidase). We investigated their relative contribution to Ang-(<em>1</em>-<em>7</em>) formation in vivo and also ex vivo in serum, lungs, and kidneys using models of genetic ablation coupled with pharmacological inhibitors. In wild-type (WT) mice, infusion of Ang II resulted in a rapid increase of plasma Ang-(<em>1</em>-<em>7</em>). In <i>ACE2</i>^-^/-/<i>PRCP</i>^-^/- mice, Ang II infusion resulted in a similar increase in Ang-(<em>1</em>-<em>7</em>) as in WT (563±48 versus 53<em>7</em>±<em>7</em>0 fmol/mL, respectively), showing that the bulk of Ang-(<em>1</em>-<em>7</em>) formation in circulation is essentially independent of ACE2 and PRCP. By contrast, a POP inhibitor, Z-Pro-Prolinal reduced the rise in plasma Ang-(<em>1</em>-<em>7</em>) after infusing Ang II to control WT mice. In POP^-/- mice, the increase in Ang-(<em>1</em>-<em>7</em>) was also blunted as compared with WT mice (309±46 and 4<em>7</em>2±28 fmol/mL, respectively <i>P</i>=0.0<em>1</em>), and moreover, the rate of recovery from acute Ang II-induced hypertension was delayed (<i>P</i>=0.0<em>1</em>6). In ex vivo studies, POP inhibition with ZZP reduced Ang-(<em>1</em>-<em>7</em>) formation from Ang II markedly in serum and in lung lysates. By contrast, in kidney lysates, the absence of ACE2, but not POP, obliterated Ang-(<em>1</em>-<em>7</em>) formation from added Ang II. We conclude that POP is the main enzyme responsible for Ang II conversion to Ang-(<em>1</em>-<em>7</em>) in the circulation and in the lungs, whereas Ang-(<em>1</em>-<em>7</em>) formation in the kidney is mainly ACE2-dependent.

The chorionic villi in the placenta are responsible for the regulation of fetal oxygen and nutrient transport. Although the peripheral renin-<em>angiotensin</em> system is activated during normal pregnancy, the regulation of the local chorionic villi renin-<em>angiotensin</em> system remains unknown. Therefore, placental chorionic villous tissue was collected from nulliparous third-trimester normotensive or preeclamptic subjects and was analyzed for <em>angiotensin</em> peptide content, <em>angiotensin</em>ogen, renin, <em>angiotensin</em>-converting enzyme (ACE), ACE2, neprilysin, <em>angiotensin</em> II type <em>1</em> (AT(<em>1</em>)), <em>angiotensin</em> II type 2, Mas receptor mRNAs, and <em>angiotensin</em> receptor density and subtype. <em>Angiotensin</em> II in chorionic villi was significantly higher in preeclamptic subjects, whereas <em>angiotensin</em> (<em>1</em>-<em>7</em>) was not different. <em>Angiotensin</em>ogen and AT(<em>1</em>) receptor gene expression was significantly higher in preeclamptic subjects. No differences were observed in renin, ACE, ACE2, or neprilysin gene expression. Mas receptor mRNA in preeclamptic subjects was decreased. The AT(<em>1</em>) receptor was the predominant receptor subtype in normal and preeclamptic chorionic villi. There was no difference in the density of the AT(<em>1</em>,) <em>angiotensin</em> II type 2, and <em>angiotensin</em> (<em>1</em>-<em>7</em>) receptors. These results indicate that enhanced chorionic villous expression of <em>angiotensin</em> II may result from increased <em>angiotensin</em>ogen. Elevated <em>angiotensin</em> II, acting through the AT(<em>1</em>) receptor, may favor vasoconstriction in placental chorionic villi and contribute to impaired fetal blood flow and decreased fetal nutrition observed during preeclampsia.

It is well established that renin-<em>angiotensin</em> system blockers exert NO/prostacyclin-dependent antithrombotic effects. Because some beneficial effects of these drugs are mediated by <em>angiotensin</em> (Ang)-(<em>1</em>-<em>7</em>), in the present study we examined if their antithrombotic action could be mediated by Ang-(<em>1</em>-<em>7</em>). Intravenous infusion of Ang-(<em>1</em>-<em>7</em>) (<em>1</em>, <em>1</em>0, or <em>1</em>00 pmol/kg per minute for 2 hours) into rats developing venous thrombosis caused 50% to <em>7</em>0% reduction of the thrombus weight. This effect was dose-dependently reversed by cotreatment with A-<em>7</em><em>7</em>9 (selective Ang-[<em>1</em>-<em>7</em>] receptor antagonist) or EXP 3<em>1</em><em>7</em>4 (<em>angiotensin</em> type <em>1</em> receptor antagonist) but not by PD <em>1</em>23,3<em>1</em>9 (<em>angiotensin</em> type 2 receptor antagonist). Similarly, the antithrombotic effects of captopril (ACE inhibitor) and losartan (<em>angiotensin</em> type <em>1</em> receptor blocker) were attenuated by A-<em>7</em><em>7</em>9 in a dose-dependent manner. The effect of Ang-(<em>1</em>-<em>7</em>) was completely abolished by concomitant administration of NO synthase inhibitor (N(G)-nitro-L-arginine methyl ester) and prostacyclin synthesis inhibitor (indomethacin), as has been shown previously for captopril and losartan. Thus, the antithrombotic effect of renin-<em>angiotensin</em> system blockers involves Ang-(<em>1</em>-<em>7</em>)-evoked release of NO and prostacyclin.

Human and ovine pregnancies are associated with increases in plasma levels of estrogens and <em>angiotensin</em> II (ANG II), cardiac output (CO), blood volume (BV), and uterine blood flow (UBF), as well as attenuated ANG II pressor responses. We hypothesized that, in nonpregnant animals, prolonged estradiol-<em>1</em><em>7</em> beta (E2 beta) treatment would reproduce these endocrine and hemodynamic alterations. Nonpregnant ovariectomized ewes (n = 5) received 5 microgram E2 beta/kg iv followed by 220 micrograms/day for <em>1</em>4 days. Plasma E2 beta increased from 36 +/- 6 to 269 +/- <em>7</em>9 (SE) pg/ml (P < 0.05) during E2 beta treatment, returning to control values 4 days posttreatment. By 3 days of E2 beta, mean arterial pressure (MAP) and systemic vascular resistance (SVR) fell 9 +/- <em>1</em> and 29 +/- <em>1</em>%, whereas heart rate (HR) and CO increased 20 +/- 5 and 26 +/- <em>1</em>% (P < 0.05). Stroke volume (SV), BV, and plasma volume were unchanged until <em>7</em> days of E2 beta, with values rising <em>1</em><em>7</em> +/- 5, <em>1</em>3 +/- 3, and <em>1</em>4 +/- 4, respectively (P < 0.05). Although MAP remained similarly depressed (-<em>1</em><em>1</em> +/- <em>1</em>%) during week 2 of E2 beta, SVR decreased further (-3<em>7</em> +/- 3%) and was associated with additional increases (P < 0.05) in CO to 44 +/- 5%, reflecting rises in SV (2<em>1</em> +/- 2%) but not HR. Increases in BV correlated with rises in CO (r = 0.55) and SV (r = 0.64) but not HR (r = -0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

It is known that <em>angiotensin</em> (Ang)-converting enzyme (ACE) 2 catalyzes Ang II to Ang <em>1</em>-<em>7</em> to prevent the detrimental effect of Ang II on blood pressure, renal fibrosis, and inflammation. However, mechanisms of renoprotective role of Ace2 remain largely unclear. The present study tested the hypothesis that deficiency of Ace2 may accelerate intrarenal Ang II-mediated fibrosis and inflammation independent of blood pressure in a model of unilateral ureteral obstructive (UUO) nephropathy induced in Ace2(+/y) and Ace2(-/y) mice. Results showed that both Ace2(+/y) and Ace2(-/y) mice had normal levels of blood pressure and plasma Ang II/Ang <em>1</em>-<em>7</em>. In contrast, deletion of ACE2 resulted in a fourfold increase in the ratio of intrarenal Ang II/Ang <em>1</em>-<em>7</em> in the UUO nephropathy. These changes were associated with the development of more intensive tubulointerstitial fibrosis (α-SMA, collagen I) and inflammation (TNF-α, IL-<em>1</em>β, MCP-<em>1</em>, F4/80(+) cells, and CD3(+)T cells) in Ace2(-/y) mice at day 3 (all P<0.05) after UUO, becoming more profound at day <em>7</em> (all P<0.0<em>1</em>). Enhanced renal fibrosis and inflammation in the UUO kidney of Ace2(-/y) mice were largely attributed to a marked increase in the intrarenal Ang II signaling (AT<em>1</em>-ERK<em>1</em>/2 mitogen-activated protein kinase), TGF-β/Smad2/3, and NF-κB signaling pathways. Further studies revealed that enhanced TGF-β/Smad and NF-κB signaling in the UUO kidney of Ace2(-/y) mice was associated with upregulation of an E3 ligase Smurf2 and a loss of renal Smad<em>7</em>. In conclusion, enhanced Ang II-mediated TGF-β/Smad and NF-κB signaling may be the mechanisms by which loss of Ace2 enhances renal fibrosis and inflammation. Smad<em>7</em> ubiquitin degradation mediated by Smurf2 may be a central mechanism by which Ace2(-/y) mice promote TGF-β/Smad2/3-mediated renal fibrosis and NF-κB-driven renal inflammation in a mouse model of UUO nephropathy.