RESUMO
Lead exposure can induce increased blood pressure. Several mechanisms have been proposed to explain lead-induced hypertension. Changes in angiotensinogen (AGT) expression levels or gene variants may also influence blood pressure. In this study, we hypothesized that AGT expression levels or gene variants contribute to lead-induced hypertension. A preliminary HEK293 cell model experiment was performed to analyze the association between AGT expression and lead exposure. In a population-based study, serum AGT level was measured in both lead-exposed and control populations. To further detect the influence of AGT gene single nucleotide polymorphisms (SNPs) in lead-induced hypertension, two SNPs (rs699 and rs4762) were genotyped in a case-control study including 219 lead-exposed subjects and 393 controls. Lead exposure caused an increase in AGT expression level in HEK 293 cell models (P < 0.001) compared to lead-free cells, and individuals exposed to lead had higher systolic and diastolic blood pressure (P < 0.001). Lead-exposed individuals had higher serum AGT levels compared to controls (P < 0.001). However, no association was found between AGT gene SNPs (rs699 and rs4762) and lead exposure. Nevertheless, the change in AGT expression level may play an important role in the development of lead-induced hypertension.
Assuntos
Angiotensinogênio/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Exposição Ambiental/efeitos adversos , Regulação da Expressão Gênica/efeitos dos fármacos , Células HEK293/efeitos dos fármacos , Hipertensão/etiologia , Chumbo/efeitos adversos , Angiotensinogênio/genética , Estudos de Casos e Controles , China , Feminino , Genótipo , Haplótipos , Humanos , Masculino , Mutagênicos/efeitos adversos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
INTRODUCTION AND OBJECTIVES: Reactive oxygen species (ROS) are produced during the interaction between oxalate/calcium oxalate monohydrate (COM) crystals and renal epithelial cells and are responsible for the various cellular responses through the activation of NADPH oxidase (Nox). Ox and COM also activate the renin-angiotensin-aldosterone system (RAAS). Aldosterone stimulates ROS production through activation of Nox with the involvement of mineralocorticoid receptor (MR), Rac1 and mitogen-activated protein kinases (MAPK). We investigated RAAS pathways in vivo in an animal model of hyperoxaluria and in vitro by exposing renal epithelial cells to COM crystals. METHODS: Hyperoxaluria was induced in male SD rats by administering ethylene glycol. One group of rats was additionally given spironolactone. Total RNA was extracted and subjected to genomic microarrays to obtain global transcriptome data. Normal rat kidney cell line (NRK-52E) was incubated with aldosterone(10(-7) M) and COM(67 µg/cm(2)) with or without spironolactone(10(-5) M), a selective inhibitor of SRC family of kinases; protein phosphatase 2(pp2) (10(-5) M) and Nox inhibitor; diphenylene iodonium (DPI) (10(-5) M). RESULTS: Relative expression of genes encoding for AGT, angiotensin receptors 1b and 2, Renin 1, Cyp11b, HSD11B2, Nr3c2, NOx4 and Rac1 was upregulated in the kidneys of rats with hyperoxaluria. Treatment with spironolactone reversed the effect of hyperoxaluria. Both aldosterone and COM crystals activated Nox and Rac1 expression in NRK52E, while spironolactone inhibited Nox and Rac1 expression. Increased Rac1 expression was significantly attenuated by treatment with PP2 and spironolactone. CONCLUSIONS: Results indicate that hyperoxaluria-induced production of ROS, injury and inflammation are in part associated with the activation of Nox through renin-angiotensin-aldosterone pathway.
Assuntos
Oxalato de Cálcio/metabolismo , Hiperoxalúria/genética , NADPH Oxidases/metabolismo , RNA Mensageiro/metabolismo , Sistema Renina-Angiotensina/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/efeitos dos fármacos , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/metabolismo , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/genética , Angiotensinogênio/metabolismo , Animais , Linhagem Celular , Citocromo P-450 CYP11B2/efeitos dos fármacos , Citocromo P-450 CYP11B2/genética , Citocromo P-450 CYP11B2/metabolismo , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Etilenoglicol/toxicidade , Perfilação da Expressão Gênica , Hiperoxalúria/induzido quimicamente , Hiperoxalúria/metabolismo , Masculino , Antagonistas de Receptores de Mineralocorticoides/farmacologia , NADPH Oxidase 4 , NADPH Oxidases/efeitos dos fármacos , NADPH Oxidases/genética , Oniocompostos/farmacologia , Proteína Fosfatase 2/farmacologia , RNA Mensageiro/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores de Angiotensina/efeitos dos fármacos , Receptores de Angiotensina/genética , Receptores de Angiotensina/metabolismo , Receptores de Mineralocorticoides/efeitos dos fármacos , Receptores de Mineralocorticoides/genética , Receptores de Mineralocorticoides/metabolismo , Renina/efeitos dos fármacos , Renina/genética , Renina/metabolismo , Sistema Renina-Angiotensina/efeitos dos fármacos , Espironolactona/farmacologia , Esteroide 11-beta-Hidroxilase/efeitos dos fármacos , Esteroide 11-beta-Hidroxilase/genética , Esteroide 11-beta-Hidroxilase/metabolismo , Proteínas rac1 de Ligação ao GTP/efeitos dos fármacos , Proteínas rac1 de Ligação ao GTP/genética , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
BACKGROUND: Recently, it has been reported that urinary angiotensinogen levels is a specific index of the intrarenal renin-angiotensin-aldosterone system (RAAS) status and it is significantly correlated with urinary albumin:creatinine (Cr) ratio in hypertensive patients. The aim of the present study was to assess the effect of activation of the Vitamin D receptor with calcitriol on albuminuria and urinary angiotensinogen as a novel biomarker of the intra-renal RAAS status in patients with diabetic nephropathy (DN). METHODS: Ninety-eight patients with type 2 diabetes and albuminuria who were treated with RAAS inhibitors (angiotensin-converting enzyme inhibitor (ACE-i) or angiotensin receptor blocker (ARB)) have participated in this study. Patients were randomized to receive either placebo (n = 50) or 0.25 µg/day calcitriol (n = 48). We have examined urinary albumin:Cr ratio and urinary angiotensinogen:Cr ratio before and 24 weeks later after treatment in both group. RESULTS: The mean urinary albumin:Cr ratio and urinary angiotensinogen:Cr ratio were significantly higher in patients with DN than in normal controls (p < 0.001). Urinary angiotensinogen:Cr ratio was significantly, positively correlated with urinary albumin:Cr ratio in both groups (in the placebo group; p = 0.01, r = 0.4236, in calcitriol group; p = 0.01, r = 0.4564). CONCLUSION: These data indicated that administration of Vitamin D receptor activator in combination with RAAS inhibitors had an additional benefit in lowering albuminuria in patients with DN. More pronounced reduction of urinary albumin:Cr ratio that was positively correlated with angiotensinogen:Cr ratio in calcitriol group suggested that Vitamin D receptor activation might blunt albuminuria by reducing urinary angiotensinogen levels reflecting intra-renal RAAS status.
Assuntos
Albuminúria/tratamento farmacológico , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/urina , Calcitriol/farmacologia , Diabetes Mellitus Tipo 2/complicações , Nefropatias Diabéticas/urina , Receptores de Calcitriol/efeitos dos fármacos , Insuficiência Renal Crônica/urina , Calcitriol/uso terapêutico , Nefropatias Diabéticas/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/complicações , Sistema Renina-Angiotensina/efeitos dos fármacosRESUMO
The renin-angiotensin system is a major determinant of blood pressure regulation. It consists of a cascade of enzymatic reactions involving 3 components: angiotensinogen, renin, and angiotensin-converting enzyme, which generate angiotensin II as a biologically active product. Angiotensinogen is largely produced in the liver, acting as a major determinant of the circulating renin-angiotensin system, which exerts acute hemodynamic effects on blood pressure regulation. How the expression of angiotensinogen is regulated is not completely understood. Here, we hypothesize that angiotensinogen is regulated by forkhead transcription factor forkhead box class O1 (Foxo1), an insulin-suppressed transcription factor, and thereby controls blood pressure in mice. We generated liver-specific Foxo1 knockout mice, which exhibited a reduction in plasma angiotensinogen and angiotensin II levels and a significant decrease in blood pressure. Using hepatocyte cultures, we demonstrated that overexpression of Foxo1 increased angiotensinogen expression, whereas hepatocytes lacking Foxo1 demonstrated a reduction of angiotensinogen gene expression and partially impaired insulin inhibition on angiotensinogen gene expression. Furthermore, mouse angiotensinogen prompter analysis demonstrated that the angiotensinogen promoter region contains a functional Foxo1-binding site, which is responsible for both Foxo1 stimulation and insulin suppression on the promoter activity. Together, these data demonstrate that Foxo1 regulates hepatic angiotensinogen gene expression and controls plasma angiotensinogen and angiotensin II levels, modulating blood pressure control in mice.
Assuntos
Angiotensinogênio/fisiologia , Pressão Sanguínea/fisiologia , Fatores de Transcrição Forkhead/fisiologia , Hemodinâmica/fisiologia , Fígado/fisiologia , Angiotensina II/efeitos dos fármacos , Angiotensina II/genética , Angiotensina II/fisiologia , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/genética , Animais , Células Cultivadas , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/deficiência , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/fisiologia , Insulina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Sistema Renina-Angiotensina/fisiologiaRESUMO
BACKGROUND: Discriminant analysis (DA) was performed on data of two combined hormonal contraceptives (CHC) differing in estrogen ratio to explore whether a combination of variables rather than a single variable distinguishes CHCs better. STUDY DESIGN: Data were used of a parallel study in premenopausal women treated for three cycles (21 days on, 7 days off) with a contraceptive vaginal ring delivering Nestorone and ethinyl estradiol (EE) or an oral contraceptive containing levonorgestrel and EE. DA was performed on the change from baseline (CFB) and the end-of-treatment values at 3 months for lipids, sex-hormone binding globulin (SHBG), C-reactive protein, angiotensinogen, blood pressure and hemostasis variables, and on the hemostasis variables only. RESULTS: For the complete set, the CFB for factor VII (FVII), SHBG and plasminogen (PLG), or end-of-treatment SHBG- and FVII level discriminated the treatments best. Maximal discrimination for the hemostasis data was by CFB for FVII and PLG or end-of-treatment FVII level. CONCLUSIONS: DA identifies differences between CHCs and may provide information on the factors associated with thrombotic risk.
Assuntos
Fatores de Coagulação Sanguínea/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Proteína C-Reativa/efeitos dos fármacos , Anticoncepcionais Orais Combinados/farmacologia , Etinilestradiol/farmacologia , Levanogestrel/farmacologia , Norprogesteronas/farmacologia , Globulina de Ligação a Hormônio Sexual/efeitos dos fármacos , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/metabolismo , Proteína C-Reativa/metabolismo , HDL-Colesterol/efeitos dos fármacos , HDL-Colesterol/metabolismo , LDL-Colesterol/efeitos dos fármacos , LDL-Colesterol/metabolismo , Dispositivos Anticoncepcionais Femininos , Análise Discriminante , Combinação de Medicamentos , Feminino , Humanos , Risco , Globulina de Ligação a Hormônio Sexual/metabolismo , Trombose/induzido quimicamente , Trombose/epidemiologia , Triglicerídeos/metabolismoRESUMO
In addition to its role as an energy store, adipose tissue also acts as an endocrine organ, synthesizing and secreting hormones and cytokines. This review discusses angiotensin II (Ang-II), the biologically active component of the renin-angiotensin system (RAS). Evidence suggests that a functioning RAS is present in adipose tissue. Animal studies have demonstrated that modifying the amount of Ang-II in the body (eg, using RAS knockout/transgenic animal models or the pharmacological treatment of animal models to prevent the formation or action of Ang-II) directly influences body weight and adiposity. In humans, body fat is correlated with levels of angiotensinogen, a precursor of Ang-II. Thus, the treatment of obesity could be improved through the use of substances that interfere with Ang-II.
Assuntos
Angiotensina II/metabolismo , Obesidade/prevenção & controle , Sistema Renina-Angiotensina/efeitos dos fármacos , Tecido Adiposo/metabolismo , Adiposidade/efeitos dos fármacos , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Obesidade/fisiopatologia , Receptores de AngiotensinaRESUMO
We studied the effects of extremely low-dose human renin inhibition (aliskiren) with low angiotensin II receptor blockade (losartan) in a novel double-transgenic rat model harbouring both human renin and angiotensinogen genes. We found that low-dose aliskiren and low-dose losartan effectively reduced mortality and target-organ damage with minimal, non-significant, effects on blood pressure (BP). Our data suggest that renin-angiotensin system (RAS) inhibition ameliorates target-organ damage in an Ang II-driven model of hypertension. Direct renin inhibition is equally efficacious in this regard. Our study does not fully answer the question of BP-lowering versus RAS inhibition. This question is important and was at least partially addressed with our low-dose model.
Assuntos
Amidas/farmacologia , Angiotensinogênio/genética , Anti-Hipertensivos/farmacologia , Fumaratos/farmacologia , Hipertensão/genética , Receptor Tipo 1 de Angiotensina/fisiologia , Renina/genética , Angiotensinogênio/efeitos dos fármacos , Animais , Animais Geneticamente Modificados , Humanos , Hipertensão/tratamento farmacológico , Ratos , Receptor Tipo 1 de Angiotensina/efeitos dos fármacos , Renina/efeitos dos fármacos , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologiaRESUMO
Observational studies have documented an association between lower rates of cardiovascular disease and hormone therapy (HT). Meanwhile, randomized clinical trials have documented increased rates of myocardial infarction and stroke in women receiving hormone therapy. These seemingly discordant findings have stimulated new research to examine estrogen's effects on the cardiovascular system, including its effects on blood pressure, regulation of the renin-angiotensin system (RAS), and the clinical consequences of hypertension. In the last 6 years several studies have better defined the mechanisms by which HT affect the RAS, blood pressure, and the clinical effects of hypertension. Recent studies documented increases in angiotensinogen synthesis and the suppression of active renin with estrogen replacement. Genotype may be a factor in determining the degree of suppression of angiotensin converting enzyme levels that occurs with estrogen therapy. Estrogen supplementation in postmenopausal women increases systemic angiotensin II, a potent vasoconstrictor. This vasopressor effect is attenuated by an estrogen-induced reduction of angiotensin II type 1 receptor expression. Renal blood flow reduction, in the absence of blood pressure changes, have been reported after estrogen replacement, and an increased risk of total stroke has been demonstrated in hypertensive women on HT compared to normotensive women on this therapy. Estrogen replacement affects many components of the RAS, but its effect on this system has little effect on blood pressure. Further studies are needed to describe the effects of estrogen replacement on abnormal vasculature and how these effects relate to myocardial infarction and stroke.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Terapia de Reposição de Estrogênios , Pós-Menopausa , Circulação Renal/efeitos dos fármacos , Sistema Renina-Angiotensina/efeitos dos fármacos , Angiotensina II/metabolismo , Angiotensinogênio/biossíntese , Angiotensinogênio/efeitos dos fármacos , Terapia de Reposição de Estrogênios/efeitos adversos , Feminino , Genótipo , Humanos , Renina/efeitos dos fármacos , Renina/metabolismo , Fatores de RiscoRESUMO
OBJECTIVE: Because inhibition of the renin-angiotensin system (RAS) reduces the onset of type 2 diabetes (T2D) and prevents atherosclerosis, we investigated the expression of RAS in the arterial wall of T2D and nondiabetic (CTR) patients. METHODS AND RESULTS: mRNA and protein levels of angiotensinogen (AGT), angiotensin-converting enzyme (ACE) and AT1 receptor (AT1R) were determined in carotid atheroma plaque, nearby macroscopically intact tissue (MIT), and in vascular smooth muscle cells (VSMCs) before and after insulin stimulation from 21 T2D and 22 CTR patients. AGT and ACE mRNA and their protein levels were 2- to 3-fold higher in atheroma and in MIT of T2D patients. VSMCs from T2D patients had respectively 2.5- and 5-fold higher AGT and AT1R mRNA and protein contents. Insulin induced an increase in AGT and AT1R mRNA with similar ED50. These responses were blocked by PD98059, an inhibitor of MAP-kinase in the two groups whereas wortmannin, an inhibitor of PI3-kinase, partially prevented the response in CTR patients. Phosphorylated ERK1-2 was 4-fold higher in MIT from T2D than from CTR patients. CONCLUSIONS: The arterial RAS is upregulated in T2D patients, which can be partly explained by an hyperactivation of the ERK1-2 pathway by insulin.
Assuntos
Angiotensinogênio/efeitos dos fármacos , Doenças das Artérias Carótidas/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Insulina/farmacologia , Receptor Tipo 1 de Angiotensina/metabolismo , Idoso , Análise de Variância , Angiotensinogênio/biossíntese , Aterosclerose/etiologia , Aterosclerose/metabolismo , Aterosclerose/patologia , Biomarcadores/metabolismo , Western Blotting , Doenças das Artérias Carótidas/etiologia , Doenças das Artérias Carótidas/patologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Probabilidade , RNA/metabolismo , RNA Mensageiro/análise , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Técnicas de Cultura de Tecidos , Regulação para CimaRESUMO
The present study aimed to investigate the effects of olmesartan, an antagonist for angiotensin II receptor type 1(AT1), on the activation of extracellular signal-regulated kinases (ERK)1/2, tissue remodeling, and pro-inflammatory signals in the right ventricle and lung of mice during the early phase of hypobaric hypoxia. Phosphorylation of ERK1/2 in both tissue types in response to hypoxia peaked at 1-3 days, and declined rapidly in the right ventricle, whereas in the lung it was sustained for at least 8 days. Upregulation of angiotensinogen mRNA was observed in the hypoxic lung at 4-9 days, but not in the hypoxic right ventricle and pulmonary artery. Olmesartan inhibited the hypoxia-induced phosphorylation of ERK1/2 in the lung, but not in the right ventricle. Neither right ventricular hypertrophy nor the thickening of the intrapulmonary arterial wall was ameliorated by olmesartan. However, this drug inhibited the expression of the mRNA for angiotensinogen and several pro-inflammatory factors, including interleukin-6 and inducible nitric oxide synthase in the hypoxic lung. These results suggest that olmesartan blocks a potential positive feedback loop of the angiotensin II-AT1 receptor system, which may lead to attenuate pro-inflammatory signals in the mouse lung, that are associated with hypoxic pulmonary hypertension, without inducing any appreciable effects on the compensatory cardiopulmonary hypertrophy at an early phase of exposure to a hypobaric hypoxic environment.
Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Hipertensão Pulmonar/tratamento farmacológico , Imidazóis/farmacologia , Proteína Quinase 1 Ativada por Mitógeno/efeitos dos fármacos , Proteína Quinase 3 Ativada por Mitógeno/efeitos dos fármacos , Tetrazóis/farmacologia , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/genética , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Hipóxia , Mediadores da Inflamação/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Masculino , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Olmesartana Medoxomila , Fosforilação/efeitos dos fármacos , Artéria Pulmonar/efeitos dos fármacos , RNA Mensageiro/metabolismo , Regulação para CimaRESUMO
We have described the biochemical, enzymatic, and structural properties of a chymostatin-sensitive angiotensin (Ang) I-converting elastase-2 found in the rat mesenteric arterial bed perfusate. We determined the mRNA for elastase-2 and its relative role in generating Ang II in the rat isolated aorta and carotid artery rings. In carotid rings, the Ang I-induced vasoconstrictor effect was only partially inhibited by captopril or chymostatin, whereas that of tetradecapeptide renin substrate (TDP) was greatly inhibited by chymostatin but unaffected by captopril; however, Ang I- and TDP-induced effects were abolished by the combination of both inhibitors. Effects of [Pro11-D-Ala12]-Ang I (PDA), an Ang I-converting enzyme (ACE)-resistant biologically inactive precursor of Ang II were blocked by chymostatin or N-acetyl-Ala-Ala-Pro-Leu-chloromethylketone (elastase-2 inhibitor) in carotid artery. PDA failed to induce an effect in aortic rings, and Ang I-induced contractions were completely inhibited by captopril. The mRNA for rat elastase-2 was detected in aorta, carotid, and mesenteric arteries, although its expression was found to be less important in aorta. These findings indicate the presence of a functional alternative pathway to ACE for Ang II generation in rat carotid artery and represent strong evidence of a physiological role for elastase-2; however, its functional contribution to Ang II formation in aorta appears to be negligible.
Assuntos
Angiotensina II/metabolismo , Artéria Carótida Primitiva/metabolismo , Serina Endopeptidases/metabolismo , Clorometilcetonas de Aminoácidos/farmacologia , Angiotensina I/farmacologia , Angiotensina II/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/metabolismo , Animais , Captopril/farmacologia , Artéria Carótida Primitiva/efeitos dos fármacos , Artéria Carótida Primitiva/fisiologia , Relação Dose-Resposta a Droga , Técnicas In Vitro , Masculino , Oligopeptídeos/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serina Endopeptidases/genética , Serina Endopeptidases/fisiologia , Inibidores de Serina Proteinase/farmacologia , Vasoconstrição/efeitos dos fármacosRESUMO
OBJECTIVE: Insulin has a growth-stimulating effect for vascular tissue. At the tissue level, the vascular renin-angiotensin system (RAS) may be involved in the progression of atherosclerosis or vascular hypertrophy. We previously reported that the vascular RAS activity is activated in vascular smooth muscle cells (SMC) by insulin stimulation. However, the effect of insulin on the RAS in endothelial cells (EC) is not fully understood. METHODS: Cultured human EC were incubated with or without insulin. After incubation for 48 h, cellular angiotensinogen and renin mRNA expression and levels in the cells were quantified by slot-blot hybridization and radioimmunoassay. Angiotensin I converting enzyme (ACE) activity in EC homogenates was measured by modified Cushman and Cheung method. EC growth and SMC with or without EC using co-culture were assessed by 3H-thymidine uptake for evaluation of their growth. RESULTS: All doses of insulin (10, 100, 1000 microU/ml) decreased angiotensinogen and renin mRNA expression (angiotensinogen: 19.3%, P < 0.05; 25.4%, P < 0.01; 26.2%, P < 0.01, renin: 12.9%, P < 0.05; 21.3%, P < 0.01; 14.3%, P < 0.05, respectively). Both cellular angiotensinogen and renin level were also reduced by high levels of insulin. Neither 10 nor 100 microU/ml insulin increased cellular angiotensin converting enzyme (ACE) activity (2.17 to 3.48-folds, P = 0.077, 0.125, respectively) significantly, but 1000 microU/ml insulin strongly up-regulated ACE activity by 16.67-folds (P = 0.001) in cultured EC. For the co-culture with EC and SMC, 100 microU/ml insulin was not able to induce SMC but 1000 microU/ml insulin accelerated SMC growth in the co-culture. In contrast insulin that was over 100 microU/ml induced SMC growth in the sole culture of SMC. CONCLUSION: Either low or high levels of insulin suppressed angiotensinogen and renin expression, however, high doses of insulin stimulated ACE activity in cultured human aortic EC. This may indicate that insulin regulates vascular cell growth and endothelial function via bifunctional modification of the vascular angiotensin generation.
Assuntos
Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologia , Angiotensinogênio/biossíntese , Angiotensinogênio/efeitos dos fármacos , Aorta/citologia , Aorta/metabolismo , Células Cultivadas , Relação Dose-Resposta a Droga , Endotélio Vascular/metabolismo , Humanos , Músculo Liso Vascular/citologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Peptidil Dipeptidase A/efeitos dos fármacos , Peptidil Dipeptidase A/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/efeitos dos fármacos , Receptor Tipo 1 de Angiotensina/biossíntese , Receptor Tipo 1 de Angiotensina/efeitos dos fármacos , Renina/biossíntese , Renina/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacosRESUMO
1. Fetal exposure to an adverse intrauterine environment has been linked with cardiovascular and metabolic disease later in life. We have shown previously, in sheep, that brief exposure (48 h) to maternally administered dexamethasone (0.28 mg/kg per day) at 27 days of gestation (prenatal treatment group (PTG) 1; term approximately 150 days), but not at 64 days of gestation (PTG2), produced hypertensive offspring at 40 months of age. The present study aimed to determine whether the elevated blood pressure in these sheep was associated with an altered peripheral renin-angiotensin system (RAS). 2. Measurements of the basal levels of the RAS components (renin, angiotensinogen, angiotensin (Ang) I, angiotensin- converting enzyme (ACE), AngII and Ang-(1-7)) were made. In addition, we studied the effect of a peripherally administered AngII type 1 (AT1) receptor antagonist (irbesartan at 1.02 mg/kg per h) on mean arterial pressure (MAP) over 4.5 h. 3. There was no significant difference in basal plasma concentrations of the components of the RAS measured between control (n = 7) and PTG1 (n = 5) or PTG2 (n = 6) animals. The MAP in PTG1 was significantly higher than in the control group during both vehicle infusion and AT1 receptor blockade. The effect of 4.5 h irbesartan (1.02 mg/kg per h) infusion on blood pressure was similar between the groups. 4. In conclusion, intrauterine exposure for 48 h to maternally administered dexamethasone at 27 days of gestation caused elevated blood pressure in adult sheep that does not appear to be associated with an alteration in the peripheral RAS.
Assuntos
Angiotensinogênio/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Dexametasona/farmacologia , Glucocorticoides/farmacologia , Hipertensão/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal , Sistema Renina-Angiotensina/efeitos dos fármacos , Renina/efeitos dos fármacos , Angiotensina II/farmacologia , Antagonistas de Receptores de Angiotensina , Angiotensinogênio/sangue , Animais , Anti-Hipertensivos/farmacologia , Compostos de Bifenilo/farmacologia , Pressão Sanguínea/fisiologia , Feminino , Hipertensão/sangue , Irbesartana , Gravidez , Receptor Tipo 1 de Angiotensina , Receptor Tipo 2 de Angiotensina , Renina/sangue , Sistema Renina-Angiotensina/fisiologia , Ovinos , Tetrazóis/farmacologia , Vasoconstritores/farmacologiaRESUMO
The circulating level of angiotensinogen (AGT) is dynamically regulated as an important determinant of blood pressure and electrolyte homeostasis. Because the mechanisms controlling the regulated expression of human angiotensinogen (hAGT) are unknown, we investigated the inducible regulation of the hAGT gene in well differentiated HepG2 cells. Interleukin-6 (IL-6) stimulation produced a 3.2-fold increase in hAGT mRNA peaking at 96 h after stimulation. Deletional mutagenesis of the hAGT promoter in transient transfection assays identified an IL-6 response domain between nucleotides -350 and -122 containing three reiterated motifs, termed human acute phase response elements (hAPREs). Although mutation of each site individually caused a fall in IL-6-inducible luciferase activity, mutation of all three sites was required to block the IL-6 effect. Electrophoretic mobility shift assay (EMSA), supershift, and microaffinity DNA binding assays indicate IL-6-inducible high-affinity binding of signal transducers and activators of transcription 1 and -3 (STAT1 and -3) to hAPRE1 and -3 but only low-affinity binding to hAPRE2. Expression of a dominant-negative form of STAT3, but not STAT1, produced a concentration-dependent reduction in IL-6-induced hAGT transcription and endogenous mRNA expression. These data indicate that STAT3 plays a major role in hAGT gene induction through three functionally distinct hAPREs in its promoter and suggest a mechanism for its up-regulation during the acute-phase response.
Assuntos
Angiotensinogênio/genética , Proteínas de Ligação a DNA/metabolismo , Interleucina-6/metabolismo , Transdução de Sinais , Transativadores/metabolismo , Proteínas de Fase Aguda/metabolismo , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/metabolismo , Sequência de Bases , Ligação Competitiva , Carcinoma Hepatocelular , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica , Genes Dominantes , Genes Reporter , Humanos , Interleucina-6/farmacologia , Cinética , Neoplasias Hepáticas , Luciferases/genética , Luciferases/metabolismo , Dados de Sequência Molecular , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Sequências Reguladoras de Ácido Nucleico , Elementos de Resposta/genética , Fator de Transcrição STAT1 , Fator de Transcrição STAT3 , Deleção de Sequência , Ativação Transcricional , Células Tumorais CultivadasRESUMO
UNLABELLED: Estradiol-intranasal is a nasal spray formulation containing an aqueous solution of 17beta-estradiol that has a unique pulse-like pharmacokinetic profile. In a well designed, placebo-controlled trial estradiol-intranasal 200 to 400 microg/day significantly reduced the incidence and severity of climacteric symptoms in women with moderate to severe menopausal symptoms after 4 and 12 weeks' treatment. The efficacy of estradiol-intranasal 300 microg/day was similar to that of oral estradiol 2 mg/day in this and another double-blind placebo-controlled trial. This equivalent efficacy was maintained in a subgroup of women with initially severe symptoms, and in smokers. Reductions in the incidence of atrophic vaginal mucosa and genitourinary symptoms and increases in the karyopyknotic index achieved with estradiol-intranasal 300 microg/day were also similar to those observed with oral estradiol 2 mg/day. Assessments of the effects of estradiol-intranasal on the complications of menopause (increased risk of cardiovascular disease and osteoporosis) are ongoing; however, estradiol-intranasal (sequentially combined with a progestogen) produced significant beneficial effects on some lipid parameters and on markers of bone resorption and formation, and bone mineral density in postmenopausal women. Estradiol-intranasal had no significant effects on serum levels of most of the assessed haemostatic factors, or on angiotensinogen or insulin levels. Estradiol-intranasal 100 to 600 microg/day was generally well tolerated in clinical trials and most adverse events were mild to moderate. The most commonly reported events were nasal symptoms and mastalgia. There was no evidence of endometrial hyperplasia with up to 1 year's treatment with estradiol-intranasal 300 microg/day combined with a progestogen. The incidence of mastalgia and withdrawal or breakthrough bleeding was lower with estradiol-intranasal 300 microg/day than with oral estradiol 2 mg/day (both administered with a progestogen) in one trial. In another trial, the incidence of mastalgia was lower with estradiol-intranasal 300 microg/day than with estradiol transdermal 50 microg (both administered with a progestogen). However, the overall incidence of adverse events was similar between the two treatments in this trial. CONCLUSIONS: Estradiol-intranasal 200 to 400 microg/day (optimal initiating dose 300 microg/day) reduces the incidence and severity of menopausal climacteric symptoms and has a good tolerability profile. Thus, evidence to date suggests that estradiol-intranasal is a useful treatment option for menopausal symptoms.
Assuntos
Densidade Óssea/efeitos dos fármacos , Climatério/efeitos dos fármacos , Endométrio/efeitos dos fármacos , Estradiol/administração & dosagem , Estradiol/farmacologia , Menopausa , Administração Intranasal , Administração Oral , Adulto , Idoso , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/farmacologia , Estradiol/farmacocinética , Feminino , Hormônios Esteroides Gonadais , Humanos , Insulina/farmacologia , Metabolismo dos Lipídeos , Lipídeos/sangue , Pessoa de Meia-IdadeRESUMO
The T235 allele of the angiotensinogen (AGT) gene is associated with plasma AGT concentration and pregnancy-induced hypertension. The aim of this study was to compare changes in the circulating renin-angiotensin system after short-term (2 days) and repeated (7 days) administration of 50 microg ethinylestradiol (EE) in homozygous normotensive men (TT and MM). After repeated EE administration, renin stimulation was induced by a single oral dose of 40 mg furosemide, followed by 50 mg captopril, 12 h later. The short-term administration of EE did not induce a significant differential genotype-dependent increase in AGT concentration. In the 7-day study, TT subjects had higher peak plasma AGT concentrations than MM subjects. The more pronounced AGT increase in TT subjects resulted in similar plasma renin activity at a lower plasma active renin concentration, with a higher plasma renin activity/active renin ratio. The difference between genotypes in renin secretion resulted in readjustment of angiotensins production. In conclusion, the T235 allele of the AGT gene is associated with greater stimulation of AGT secretion in plasma after EE administration. In the short-term, complete readjustment of the circulating renin-angiotensin system occurs, through a decrease in renin release, which blunts the effects of the increase in AGT concentration.
Assuntos
Angiotensinogênio/sangue , Angiotensinogênio/genética , Etinilestradiol/farmacologia , Polimorfismo Genético , Sistema Renina-Angiotensina/efeitos dos fármacos , Renina/sangue , Adolescente , Adulto , Substituição de Aminoácidos , Angiotensinogênio/efeitos dos fármacos , Captopril/farmacologia , França , Furosemida/farmacologia , Genótipo , Homozigoto , Humanos , Cinética , Masculino , Renina/efeitos dos fármacos , População BrancaRESUMO
The effect of acutely increasing renal perfusion pressure or extracellular fluid volume on renal medullary and cortical blood flow was examined in the low-renin deoxycorticosterone acetate (DOCA)-salt hypertension model in mice. A 50-mg DOCA tablet was implanted, and 1% saline was given as drinking water for 3 wk. Medullary and cortical blood flow were determined with laser-Doppler flowmetry, and whole-kidney blood flow was measured with a transit-time ultrasound flowprobe around the renal artery. In control mice, total renal blood flow ranged from 6.3 and 7.6 ml/min per g kidney weight and in DOCA-salt mice from 4.3 and 4.7 ml/min per g kidney weight, respectively, and was minimally affected as renal perfusion pressure was increased. Renal vascular resistance increased correspondingly. During stepwise increases in renal artery pressure from 90 to 140 mmHg, medullary blood flow progressively increased in control mice to 125% of baseline values, whereas cortical blood flow did not change. In DOCA-salt mice, increasing BP from 100 to 154 mmHg had no effect on either cortical or medullary blood flow. Urine flow and sodium excretion were lower in DOCA-salt mice than in controls and increased nearly to the same extent in both groups after volume expansion with isotonic saline. Total renal blood flow increased after saline loading, more in controls than in DOCA-salt mice. Increases in medullary blood flow after saline loading were up to 122% of baseline values in controls and demonstrated a significantly steeper slope than the 110% of baseline increases in DOCA-salt mice. Cortical blood flow, however, was not different between the groups. Thus, medullary blood flow is not as tightly autoregulated as cortical blood flow in normal mice. Natriuresis with acute volume loading is facilitated by increased medullary blood flow. In DOCA-salt mice, the medullary blood flow reaction to renal perfusion pressure increases is abolished, whereas flow increases with extracellular volume expansion are diminished. These results suggest that diminished pressure-natriuresis responses in DOCA-salt mice are related to perturbed medullary blood flow.
Assuntos
Hipertensão Renovascular/fisiopatologia , Córtex Renal/irrigação sanguínea , Córtex Renal/fisiopatologia , Medula Renal/irrigação sanguínea , Medula Renal/fisiopatologia , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/genética , Animais , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Volume Sanguíneo/efeitos dos fármacos , Desoxicorticosterona , Diurese/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/genética , Genes/genética , Hematócrito , Hemodinâmica , Hipertensão Renovascular/induzido quimicamente , Rim/irrigação sanguínea , Rim/química , Córtex Renal/citologia , Medula Renal/citologia , Camundongos , Natriurese/efeitos dos fármacos , Peptidil Dipeptidase A/efeitos dos fármacos , Peptidil Dipeptidase A/genética , Perfusão , Potássio/urina , Pressão , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/genética , Receptor Tipo 1 de Angiotensina , Receptor Tipo 2 de Angiotensina , Receptores de Angiotensina/efeitos dos fármacos , Receptores de Angiotensina/genética , Fluxo Sanguíneo Regional/fisiologia , Circulação Renal , Renina/efeitos dos fármacos , Renina/genética , Sistema Renina-Angiotensina/genética , Sódio/urina , Cloreto de Sódio , Micção/efeitos dos fármacos , Micção/fisiologia , Resistência Vascular/efeitos dos fármacos , Resistência Vascular/fisiologiaRESUMO
OBJECTIVES: The clinical course of hypertension or heart failure may be modified by the extent of concurrent neurohormonal activation. Factors that regulate neurohormones in patients with these conditions are complex. In the present study, we examined the relative contribution of antihypertensive therapy to the variability of neurohormonal levels in a well defined population based sample. DESIGN AND SETTING: Cross-sectional study of a mixed urban and rural population. SUBJECTS: Middle-aged individuals (n = 646) were analysed in order to elucidate determinants of neurohormone levels by uni- and multivariate comparisons. The assessment included anthropometric, echocardiographic and, if appropriate, genotype information. RESULTS: The intake of antihypertensive drugs was related to significant alterations of neurohormone levels that, in part, exceeded the contribution of all other variables studied. Multivariate analyses revealed that renin levels were independently related to the intake of beta blockers (n = 80; -8.4 mU L-1; P = 0.001), angiotensin-converting enzyme (ACE)-inhibitors (n = 39; +15.9 mU L-1; P = 0.0001), diuretics (n = 62; +14.3 mU L-1; P = 0.0001), and calcium channel blockers (n = 45; +5.9 mU L-1; P = 0.05). Aldosterone levels were related to ACE-inhibition (-156.5 pmol L-1; P = 0.04) and diuretic treatment (+422.4 pmol L-1; P = 0.0001) in an opposite fashion whereas beta blockers and calcium channel blockers had no significant independent effects. The levels of the atrial natriuretic peptide were significantly related to the use of beta blockers (+3.9 pmol L-1; P = 0.002) and calcium channel blockers (+3.1 pmol L-1; P = 0.05). Finally, serum angiotensinogen levels and ACE activity were not found to be significantly affected by antihypertensive medication but were rather related to gender or genotype. CONCLUSIONS: The data emphasize that antihypertensive treatment with different classes of drugs may modulate serum levels of neurohormones substantially resulting in distinct patterns of activation. These drug-related effects may require consideration when neurohormonal activation is of functional relevance or when neurohormones serve as prognostic predictors in patients with cardiovascular disorders.
Assuntos
Anti-Hipertensivos/farmacologia , Hormônios/sangue , Proteínas do Tecido Nervoso/efeitos dos fármacos , Antagonistas Adrenérgicos beta/farmacologia , Aldosterona/sangue , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Angiotensinogênio/sangue , Angiotensinogênio/efeitos dos fármacos , Fator Natriurético Atrial/sangue , Fator Natriurético Atrial/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/farmacologia , Estudos Transversais , Diuréticos/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/sangue , Peptidil Dipeptidase A/sangue , Peptidil Dipeptidase A/efeitos dos fármacos , População Rural , População UrbanaRESUMO
OBJECTIVE: To investigate the effect of plasma angiotensinogen on blood pressure regulation in normotensive rats, by a loss of function approach using antisense oligonucleotides. DESIGN AND METHODS: Eight-week-old male Wistar rats were transfected with antisense, sense or scrambled oligonucleotides using liposomes containing viral agglutinins, which are reported to be highly efficient in promoting fusion with target cells. The abdomen was opened with a median incision, and the liver and portal vein were exposed. Then 2.5 ml of hemagglutinating virus-liposome complex containing oligonucleotides was introduced into the liver by multiple direct injections or infusion via the portal vein. Blood pressure, plasma angiotensinogen and angiotensin II levels were measured after transfection. The hepatic angiotensinogen level was examined by Northern blotting and radioimmunoassay. RESULTS: The in vivo injection of antisense oligonucleotides against rat angiotensinogen by the hemagglutinating virus-liposome gene transfer method into normotensive rats resulted in a transient fall in blood pressure from day 1 to day 4 after injection. This was accompanied by a decrease in plasma angiotensinogen and hepatic angiotensinogen messenger RNA levels on day 2. No significant changes were noted in untreated rats or those treated with sense or scrambled oligonucleotides. Plasma angiotensin II concentration was also reduced by antisense treatment, but not sense or scrambled treatment. CONCLUSIONS: In vivo administration of antisense angiotensinogen oligonucleotides resulted in a transient decrease in blood pressure accompanied by a decrease in plasma angiotensinogen and angiotensin II levels, which suggests that angiotensinogen plays a pivotal role in the regulation of blood pressure in normotensive rats.
Assuntos
Angiotensinogênio/sangue , Pressão Sanguínea/fisiologia , Fígado/efeitos dos fármacos , Oligonucleotídeos Antissenso/administração & dosagem , RNA Mensageiro/análise , Angiotensina II/sangue , Angiotensina II/efeitos dos fármacos , Angiotensinogênio/efeitos dos fármacos , Angiotensinogênio/genética , Animais , Sequência de Bases , Northern Blotting , Técnicas de Transferência de Genes , Infusões Intravenosas , Fígado/metabolismo , Masculino , Microscopia de Fluorescência , Dados de Sequência Molecular , Veia Porta , Ratos , Ratos WistarRESUMO
To investigate whether alpha (alpha)-adrenoceptor agonists have a stimulatory effect on the expression of the angiotensinogen (Ang) gene in opossum kidney (OK) cells, we used OK 27 cells with a fusion gene containing the 5'-flanking regulatory sequence of the rat angiotensinogen gene fused with a human growth hormone (hGH) gene as a reporter, pOGH (Ang N-1498/+18), permanently integrated into their genomes. The level of expression of the pOGH (Ang N-1498/+18) was quantitated by the amount of immunoreactive-human growth hormone (IR-hGH) secreted into the medium. The addition of iodoclonidine (alpha 2-adrenoceptor agonist, 10(-13) to 10(-9) M) and phorbol 12-myristate 13-acetate (PMA, 10(-13) to 10(-5) M) stimulated the expression of pOGH (Ang N-1498/+18) in a dose-dependent manner, whereas the addition of phenylephrine (alpha 1-adrenoceptor agonist, 10(-13) to 10(-5) M) had no effect. The stimulatory effect of iodoclonidine was blocked by the presence of yohimbine (alpha 2-adrenoceptor antagonist) and staurosporine (an inhibitor of protein kinase C) but not blocked by the presence of prazosin (alpha 1-adrenoceptor antagonist) or Rp-cAMP (an inhibitor of cAMP-dependent protein kinase A). The addition of iodoclonidine, phenylephrine or PMA had no effect on the expression of pTKGH in OK 13 cells, an OK cell line, into which had been stably integrated a fusion gene, pTKGH containing the promoter/enhancer DNA sequence of the viral thymidine-kinase (TK) gene fused with a human growth hormone gene as a reporter.(ABSTRACT TRUNCATED AT 250 WORDS)