RESUMEN
The Na+-activated Na+ channel (Nax) and salt-inducible kinase (SIK) are stimulated by increases in local Na+ concentration, affecting (Na+ + K+)-ATPase activity. To test the hypothesis that the triad Nax/SIK/(Na+ + K+)-ATPase contributes to kidney injury and salt-sensitive hypertension (HTN), uninephrectomized male Wistar rats (200 g; n = 20) were randomly divided into 4 groups based on a salt diet (normal salt diet; NSD-0.5% NaCl-or high-salt diet; HSD-4% NaCl) and subcutaneous administration of saline (0.9% NaCl) or deoxycorticosterone acetate (DOCA, 8 mg/kg), as follows: Control (CTRL), CTRL-Salt, DOCA, and DOCA-Salt, respectively. After 28 days, the following were measured: kidney function, blood pressure, (Na+ + K+)-ATPase and SIK1 kidney activities, and Nax and SIK1 renal expression levels. SIK isoforms in kidneys of CTRL rats were present in the glomerulus and tubular epithelia; they were not altered by HSD and/or HTN. CTRL-Salt rats remained normotensive but presented slight kidney function decay. HSD rats displayed augmentation of the Nax/SIK/(Na+ + K+)-ATPase pathway. HTN, kidney injury, and kidney function decay were present in all DOCA rats; these were aggravated by HSD. DOCA rats presented unaltered (Na+ + K+)-ATPase activity, diminished total SIK activity, and augmented SIK1 and Nax content in the kidney cortex. DOCA-Salt rats expressed SIK1 activity and downregulation in (Na+ + K+)-ATPase activity in the kidney cortex despite augmented Nax content. The data of this study indicate that the (Na+ + K+)-ATPase activity response to SIK is attenuated in rats under HSD, independent of HTN, as a mechanism contributing to kidney injury and salt-sensitive HTN.
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Acetato de Desoxicorticosterona , Hipertensión , Ratas , Masculino , Animales , Cloruro de Sodio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Ratas Wistar , Hipertensión/metabolismo , Sodio/metabolismo , Cloruro de Sodio Dietético/efectos adversos , Cloruro de Sodio Dietético/metabolismo , Presión Sanguínea , Riñón/metabolismo , Iones/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismoRESUMEN
Diabetes mellitus and its complications have become a major health concern in Western countries. Increased activity of the intrarenal renin-angiotensin system (RAS) contributes to diabetic nephropathy (DN). We previously reported that in mesangial cells, the high glucose concentration (HG) leads to upregulation of angiotensin-converting enzyme (ACE) messenger RNA, suggesting that ACE was modulated by angiotensin II (Ang II) release. However, this relation in the collecting duct has not yet been studied. We, therefore, aimed to evaluate RAS modulation in inner medullary collecting duct cells (IMCD) exposed to HG. The IMCD were divided into normal glucose (5 mM D-glucose, NG), high glucose (30 mM, HG), and mannitol (30 mM, M) groups. The cells were cultured 48 hr in their respective media. The intracellular and extracellular ACE activity was measured using hippuryl-His-Leu as substrate via a fluorimetric assay and expression was analyzed using western blot analysis. ACE activity, intracellular (27%) and extracellular (22%), was significantly lower in the HG group than in NG and M. ACE2 activity and Ang 1-7 levels were higher in the intracellular compartment. Our data suggest that the HG cannot modify ACE synthesis in IMCD cells but can modulate its activity. The decrease in ACE activity may result in decreased levels of Ang II to protect the IMCD against proliferative and inflammatory deleterious effects of this peptide. Conversely, the increase of ACE2 generating high levels of Ang 1-7, a vasodilator peptide, suggesting that this peptide can induce glucose uptake and protect cells against oxidative stress, which can elicit insulin resistance.
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Glucosa/toxicidad , Túbulos Renales Colectores/efectos de los fármacos , Sistema Renina-Angiotensina/efectos de los fármacos , Angiotensina I/metabolismo , Angiotensina II/metabolismo , Enzima Convertidora de Angiotensina 2 , Animales , Línea Celular , Túbulos Renales Colectores/metabolismo , Túbulos Renales Colectores/patología , Ratones , Fragmentos de Péptidos/metabolismo , Peptidil-Dipeptidasa A/metabolismoRESUMEN
Hypertension is a global health problem, and angiotensin I (ANG I)-converting enzyme (ACE) inhibitors are largely used to control this pathology. Recently, it has been shown that ACE can also act as a transducer signal molecule when its inhibitors or substrates bind to it. This new role of ACE could contribute to understanding some of the effects not explained by its catalytic activity only. In this study, we investigated signaling pathway activation in Chinese hamster ovary (CHO) cells stably expressing ACE (CHO-ACE) under different conditions. We also investigated gene modulation after 4 h and 24 h of captopril treatment. Our results demonstrated that CHO-ACE cells when stimulated with ANG I, ramipril, or captopril led to JNK and ERK1/2 phosphorylation. To verify any physiological role at the endogenous level, we made use of primary cultures of mesangial cells from spontaneously hypertensive rats (SHR) and Wistar rats. Our results showed that ERK1/2 activation occurred mainly in primary cultures of mesangial cells from SHR rats upon captopril stimulation, suggesting that this signaling pathway could be differentially regulated during hypertension. Our results also showed that captopril treatment leads to a decrease of cyclooxygenase 2, interleukin-1ß, and ß-arrestin2 and a significant increase of AP2 gene expression levels. Our findings strengthen the fact that, in addition to the blockage of enzymatic activity, ACE inhibitors also trigger signaling pathway activation, and this may contribute to their beneficial effects in the treatment of hypertension and other pathologies.
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Angiotensina I/metabolismo , Captopril/farmacología , Peptidil-Dipeptidasa A/metabolismo , Transducción de Señal/efectos de los fármacos , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Animales , Células CHO , Línea Celular , Cricetulus , Hipertensión/tratamiento farmacológico , Hipertensión/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Células Mesangiales/efectos de los fármacos , Células Mesangiales/metabolismo , Fosforilación/efectos de los fármacos , Ratas , Ratas Endogámicas SHR , Ratas WistarRESUMEN
BACKGROUND: Stem cells of intensely regenerative tissues are susceptible to cellular damage. Although the response to this process in hematopoietic stem cells (HSCs) is crucial, the mechanisms by which hematopoietic homeostasis is sustained are not completely understood. Aging increases reactive oxygen species (ROS) levels and inflammation, which contribute to increased proliferation, senescence and/or apoptosis, leading to self-renewal premature exhaustion. In this study, we assessed ROS production, DNA damage, apoptosis, senescence and plasticity in young, middle and aged (2-, 12- and 24-month-old, respectively) C57BL/6 J mice. RESULTS: Aged HSCs showed an increase in intracellular superoxide anion (1.4-fold), hydrogen peroxide (2-fold), nitric oxide (1.6-fold), peroxynitrite/hidroxil (2.6-fold) compared with young cells. We found that mitochondria and NADPHox were the major sources of ROS production in the three groups studied, whereas CYP450 contributed in middle and aged, and xanthine oxidase only in aged HSCs. In addition, we observed DNA damage and apoptosis in the middle (4.2- and 2-fold, respectively) and aged (6- and 4-fold, respectively) mice; aged mice also exhibited a significantly shorter telomere length (-1.8-fold) and a lower expression of plasticity markers. CONCLUSION: These data suggest that aging impairs the functionality of HSCs and that these age-associated alterations may affect the efficacy of aged HSC recovery and transplantation.
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Envejecimiento/metabolismo , Médula Ósea/metabolismo , Células Madre Hematopoyéticas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Envejecimiento/patología , Animales , Apoptosis , Médula Ósea/patología , Senescencia Celular , Daño del ADN , Células Madre Hematopoyéticas/patología , Masculino , RatonesRESUMEN
BACKGROUND: Hyperactivity of the renin-angiotensin system (RAS) and functional deficits in hypertension are reduced after exercise training. We evaluate in arteries, kidney and plasma of hypertensive rats the sequential effects of training on vascular angiotensinogen, Ang II and Ang (1-7) content. METHODS AND RESULTS: Spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were trained or kept sedentary (S) for 3 months. After hemodynamic measurements (weeks 0, 1, 2, 4, 8 and 12), blood, arteries and kidneys were obtained to quantify the angiotensin content (HPLC) and angiotensinogen expression (Western Blotting). SHR-S vs. WKY-S exhibited elevated pressure, increased angiotensinogen and angiotensins' content in the renal artery with a high Ang II/Ang (1-7) ratio (~5-fold higher than in the femoral artery, kidney and plasma, and 14-fold higher than in the aorta). Training promptly reduced angiotensinogen expression and downregulated the RAS in the renal SHR artery (1st-12th week), with a specific reduction of the vasoconstrictor axis; significant reduction of the AngII/Ang (1-7) ratio (36%, T4-T8) occurred simultaneously with significant pressure fall (5%). In other SHR arteries, plasma and kidneys and in all WKY tissues, T-induced AngII and Ang (1-7) reductions were proportional, maintaining the AngII/Ang (1-7) ratio. CONCLUSIONS: Vascular RAS is not equally expressed in vessels, having crucial importance in the renal artery. In the renal SHR artery, training downregulates the vasoconstrictor and preserves the vasodilator axis while in other tissues and plasma training reduces both RAS axes, thus maintaining the vasoconstriction/vasodilatation balance in a lower level.
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Angiotensina II/biosíntesis , Angiotensina I/biosíntesis , Angiotensinógeno/biosíntesis , Riñón/metabolismo , Fragmentos de Péptidos/biosíntesis , Condicionamiento Físico Animal/fisiología , Arteria Renal/metabolismo , Sistema Renina-Angiotensina/fisiología , Aerobiosis/fisiología , Angiotensina I/sangre , Angiotensina II/sangre , Enzima Convertidora de Angiotensina 2 , Angiotensinógeno/sangre , Angiotensinógeno/genética , Animales , Presión Sanguínea , Arteria Femoral , Masculino , Especificidad de Órganos , Fragmentos de Péptidos/sangre , Peptidil-Dipeptidasa A/sangre , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Carrera , Vasoconstricción/fisiología , Vasodilatación/fisiologíaRESUMEN
The details of protein pathways at a structural level provides a bridge between genetics/molecular biology and physiology. The renin-angiotensin system is involved in many physiological pathways with informative structural details in multiple components. Few studies have been performed assessing structural knowledge across the system. This assessment allows use of bioinformatics tools to fill in missing structural voids. In this paper we detail known structures of the renin-angiotensin system and use computational approaches to estimate and model components that do not have their protein structures defined. With the subsequent large library of protein structures, we then created a species specific protein library for human, mouse, rat, bovine, zebrafish, and chicken for the system. The rat structural system allowed for rapid screening of genetic variants from 51 commonly used rat strains, identifying amino acid variants in angiotensinogen, ACE2, and AT1b that are in contact positions with other macromolecules. We believe the structural map will be of value for other researchers to understand their experimental data in the context of an environment for multiple proteins, providing pdb files of proteins for the renin-angiotensin system in six species. With detailed structural descriptions of each protein, it is easier to assess a species for use in translating human diseases with animal models. Additionally, as whole genome sequencing continues to decrease in cost, tools such as molecular modeling will gain use as an initial step in designing efficient hypothesis driven research, addressing potential functional outcomes of genetic variants with precompiled protein libraries aiding in rapid characterizations.
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Angiotensinógeno/química , Evolución Biológica , Biología Computacional , Modelos Moleculares , Sistema Renina-Angiotensina , Renina/química , Secuencia de Aminoácidos , Angiotensinógeno/metabolismo , Animales , Bovinos , Pollos , Humanos , Ratones , Datos de Secuencia Molecular , Conformación Proteica , Ratas , Renina/metabolismo , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Pez CebraRESUMEN
Skeletal myopathy is a hallmark of heart failure (HF) and has been associated with a poor prognosis. HF and other chronic degenerative diseases share a common feature of a stressed system: sympathetic hyperactivity. Although beneficial acutely, chronic sympathetic hyperactivity is one of the main triggers of skeletal myopathy in HF. Considering that ß2 -adrenoceptors mediate the activity of sympathetic nervous system in skeletal muscle, we presently evaluated the contribution of ß2 -adrenoceptors for the morphofunctional alterations in skeletal muscle and also for exercise intolerance induced by HF. Male WT and ß2 -adrenoceptor knockout mice on a FVB genetic background (ß2 KO) were submitted to myocardial infarction (MI) or SHAM surgery. Ninety days after MI both WT and ß2 KO mice presented to cardiac dysfunction and remodelling accompanied by significantly increased norepinephrine and epinephrine plasma levels, exercise intolerance, changes towards more glycolytic fibres and vascular rarefaction in plantaris muscle. However, ß2 KO MI mice displayed more pronounced exercise intolerance and skeletal myopathy when compared to WT MI mice. Skeletal muscle atrophy of infarcted ß2 KO mice was paralleled by reduced levels of phosphorylated Akt at Ser 473 while increased levels of proteins related with the ubiquitin--proteasome system, and increased 26S proteasome activity. Taken together, our results suggest that lack of ß2 -adrenoceptors worsen and/or anticipate the skeletal myopathy observed in HF.
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Insuficiencia Cardíaca/complicaciones , Músculo Esquelético/patología , Atrofia Muscular/etiología , Infarto del Miocardio/complicaciones , Receptores Adrenérgicos beta 2/fisiología , Animales , Ecocardiografía , Insuficiencia Cardíaca/fisiopatología , Masculino , Ratones , Ratones Noqueados , Músculo Esquelético/metabolismo , Atrofia Muscular/patología , Infarto del Miocardio/fisiopatología , Condicionamiento Físico Animal , Complejo de la Endopetidasa Proteasomal , Transducción de Señal , Ubiquitina/metabolismoRESUMEN
To investigate whether thyroid hormone (TH) interacts with the sympathetic nervous system (SNS) to modulate bone mass and structure, we studied the effects of daily T3 treatment in a supraphysiological dose for 12 wk on the bone of young adult mice with chronic sympathetic hyperactivity owing to double-gene disruption of adrenoceptors that negatively regulate norepinephrine release, α(2A)-AR, and α(2C)-AR (α(2A/2C)-AR(-/-) mice). As expected, T3 treatment caused a generalized decrease in the areal bone mineral density (aBMD) of WT mice (determined by DEXA), followed by deleterious effects on the trabecular and cortical bone microstructural parameters (determined by µCT) of the femur and vertebra and on the biomechanical properties (maximum load, ultimate load, and stiffness) of the femur. Surprisingly, α(2A/2C)-AR(-/-) mice were resistant to most of these T3-induced negative effects. Interestingly, the mRNA expression of osteoprotegerin, a protein that limits osteoclast activity, was upregulated and downregulated by T3 in the bone of α(2A/2C)-AR(-/-) and WT mice, respectively. ß1-AR mRNA expression and IGF-I serum levels, which exert bone anabolic effects, were increased by T3 treatment only in α(2A/2C)-AR(-/-) mice. As expected, T3 inhibited the cell growth of calvaria-derived osteoblasts isolated from WT mice, but this effect was abolished or reverted in cells isolated from KO mice. Collectively, these findings support the hypothesis of a TH-SNS interaction to control bone mass and structure of young adult mice and suggests that this interaction may involve α2-AR signaling. Finally, the present findings offer new insights into the mechanisms through which TH regulates bone mass, structure, and physiology.
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Densidad Ósea/efectos de los fármacos , Huesos/efectos de los fármacos , Catecolaminas/farmacología , Sistema Nervioso Simpático/fisiología , Hormonas Tiroideas/farmacología , Animales , Desarrollo Óseo/efectos de los fármacos , Huesos/fisiología , Huesos/ultraestructura , Catecolaminas/metabolismo , Femenino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Tamaño de los Órganos/efectos de los fármacos , Hormonas Tiroideas/metabolismo , Soporte de PesoRESUMEN
Activation of NF-κB signaling in the heart may be protective or deleterious depending on the pathological context. In diabetes, the role of NF-κB in cardiac dysfunction has been investigated using pharmacological approaches that have a limitation of being nonspecific. Furthermore, the specific cellular pathways by which NF-κB modulates heart function in diabetes have not been identified. To address these questions, we used a transgenic mouse line expressing mutated IκB-α in the heart (3M mice), which prevented activation of canonical NF-κB signaling. Diabetes was developed by streptozotocin injections in wild-type (WT) and 3M mice. Diabetic WT mice developed systolic and diastolic cardiac dysfunction by the 12th week, as measured by echocardiography. In contrast, cardiac function was preserved in 3M mice up to 24 wk of diabetes. Diabetes induced an elevation in cardiac oxidative stress in diabetic WT mice but not 3M mice compared with nondiabetic control mice. In diabetic WT mice, an increase in the phospholamban/sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 ratio and decrease in ryanodine receptor expression were observed, whereas diabetic 3M mice showed an opposite effect on these parameters of Ca(2+) handling. Significantly, renin-angiotensin system activity was suppressed in diabetic 3M mice compared with an increase in WT animals. In conclusion, these results demonstrate that inhibition of NF-κB signaling in the heart prevents diabetes-induced cardiac dysfunction through preserved Ca(2+) handling and inhibition of the cardiac renin-angiotensin system.
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Cardiomiopatías Diabéticas/metabolismo , FN-kappa B/metabolismo , Sistema Renina-Angiotensina , Animales , Señalización del Calcio , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/fisiopatología , Cardiomiopatías Diabéticas/genética , Cardiomiopatías Diabéticas/prevención & control , Ratones , Ratones Endogámicos C57BL , Mutación , Miocardio/metabolismo , FN-kappa B/genética , Estrés Oxidativo , Canal Liberador de Calcio Receptor de Rianodina/genética , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/genética , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND: The clipping of an artery supplying one of the two kidneys (2K1C) activates the renin-angiotensin (Ang) system (RAS), resulting in hypertension and endothelial dysfunction. Recently, we demonstrated the intrarenal beneficial effects of sildenafil on the high levels of Ang II and reactive oxygen species (ROS) and on high blood pressure (BP) in 2K1C mice. Thus, in the present study, we tested the hypothesis that sildenafil improves endothelial function in hypertensive 2K1C mice by improving the NO/ROS balance. METHODS: 2K1C hypertension was induced in C57BL/6 mice. Two weeks later, they were treated with sildenafil (40 mg/kg/day, via oral) or vehicle for 2 weeks and compared with sham mice. At the end of the treatment, the levels of plasma and intrarenal Ang peptides were measured. Endothelial function and ROS production were assessed in mesenteric arterial bed (MAB). RESULTS: The 2K1C mice exhibited normal plasma levels of Ang I, II and 1-7, whereas the intrarenal Ang I and II were increased (~35% and ~140%) compared with the Sham mice. Sildenafil normalized the intrarenal Ang I and II and increased the plasma (~45%) and intrarenal (+15%) Ang 1-7. The 2K1C mice exhibited endothelial dysfunction, primarily due to increased ROS and decreased NO productions by endothelial cells, which were ameliorated by treatment with sildenafil. CONCLUSION: These data suggest that the effects of sildenafil on endothelial dysfunction in 2K1C mice may be due to interaction with RAS and restoring NO/ROS balance in the endothelial cells from MAB. Thus, sildenafil is a promising candidate drug for the treatment of hypertension accompanied by endothelial dysfunction and kidney disease.
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Fosfodiesterasas de Nucleótidos Cíclicos Tipo 5/metabolismo , Endotelio Vascular/fisiopatología , Hipertensión Renovascular/fisiopatología , Inhibidores de Fosfodiesterasa 5/farmacología , Angiotensinas/sangre , Animales , Presión Sanguínea , Peso Corporal , Citometría de Flujo , Frecuencia Cardíaca , Hipertensión Renovascular/enzimología , Ratones , Ratones Endogámicos C57BL , Tamaño de los Órganos , Estrés OxidativoRESUMEN
BACKGROUND: Oxidative stress and DNA damage have been implicated in the pathogenesis of renovascular hypertension induced by renal artery stenosis in the two-kidney, one-clip (2K1C) Goldblatt model. Considering our previous report indicating that the chronic blockade of phosphodiesterase 5 with sildenafil (Viagra) has marked beneficial effects on oxidative stress and DNA damage, we tested the hypothesis that sildenafil could also protect the stenotic kidneys of 2K1C hypertensive mice against oxidative stress and genotoxicity. METHODS: The experiments were performed with C57BL6 mice subjected to renovascular hypertension by left renal artery clipping. Two weeks after clipping, the mice were treated with sildenafil (40 mg/kg/day for 2 weeks, 2K1C-sildenafil group) or the vehicle (2K1C). These mice were compared with control mice not subjected to renal artery clipping (Sham). After hemodynamic measurements, the stenotic kidneys were assessed using flow cytometry to evaluate cell viability and the comet assay to evaluate DNA damage. Measurements of intracellular superoxide anions and hydrogen peroxide levels as well as nitric oxide bioavailability were also obtained. RESULTS: Sildenafil treatment significantly reduced mean arterial pressure (15%), heart rate (8%), intrarenal angiotensin II (50%) and renal atrophy (36%). In addition, it caused a remarkable decrease of reactive oxygen species production. On the other hand, sildenafil increased nitric oxide levels relative to those in the nontreated 2K1C mice. Sildenafil treatment also significantly reduced the high level of kidney DNA damage that is a characteristic of renovascular hypertensive mice. CONCLUSIONS: Our data reveal that sildenafil has a protective effect on the stenotic kidneys of 2K1C mice, suggesting a new use of phosphodiesterase 5 inhibitors for protection against the DNA damage observed in the hypoperfused kidneys of individuals with renovascular hypertension. Further translational research is necessary to delineate the mechanisms involved in the prevention of renal stenosis in the clinical setting.
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Daño del ADN , Hipertensión Renovascular/patología , Riñón/patología , Estrés Oxidativo/efectos de los fármacos , Piperazinas/farmacología , Sulfonas/farmacología , Angiotensina II/metabolismo , Animales , Presión Sanguínea/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Ensayo Cometa , Constricción Patológica/patología , Constricción Patológica/fisiopatología , Frecuencia Cardíaca/efectos de los fármacos , Hipertensión Renovascular/fisiopatología , Riñón/efectos de los fármacos , Riñón/fisiopatología , Pruebas de Función Renal , Ratones , Ratones Endogámicos C57BL , Tamaño de los Órganos/efectos de los fármacos , Purinas/farmacología , Especies Reactivas de Oxígeno/metabolismo , Arteria Renal/efectos de los fármacos , Arteria Renal/fisiopatología , Citrato de SildenafilRESUMEN
OBJECTIVES: Angiotensin-converting enzymes' (ACEs) relationship with blood pressure (BP) during childhood has not been clearly established. We aimed to compare ACE and ACE2 activities between BMI groups in a sample of prepubertal children, and to characterize the association between these enzymes' activities and BP. METHODS: Cross-sectional study of 313 children aged 8-9âyears old, included in the birth cohort Generation XXI (Portugal). Anthropometric measurements and 24-h ambulatory BP monitoring were performed. ACE and ACE2 activities were quantified by fluorometric methods. RESULTS: Overweight/obese children demonstrated significantly higher ACE and ACE2 activities, when compared to their normal weight counterparts [median (P25-P75), ACE: 39.48 (30.52-48.97) vs. 42.90 (35.62-47.18) vs. 43.38 (33.49-49.89) mU/ml, P for trend = 0.009; ACE2: 10.41 (7.58-15.47) vs. 21.56 (13.34-29.09) vs. 29.00 (22.91-34.32) pM/min per ml, P for trend < 0.001, in normal weight, overweight and obese children, respectively]. In girls, night-time systolic BP (SBP) and diastolic BP (DBP) increased across tertiles of ACE activity ( P < 0.001 and P â=â0.002, respectively). ACE2 activity was associated with higher night-time SBP and DBP in overweight/obese girls ( P â=â0.037 and P â=â0.048, respectively) and night-time DBP in the BMI z-score girl adjusted model ( P â=â0.018). Median ACE2 levels were significantly higher among nondipper girls (16.7 vs. 11.6âpM/min per ml, P â=â0.009). CONCLUSIONS: Our work shows that obesity is associated with activation of the renin-angiotensin-aldosterone system, with significant increase of ACE and ACE2 activities already in childhood. Also, we report sex differences in the association of ACE and ACE2 activities with BP.
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Obesidad Infantil , Humanos , Niño , Masculino , Femenino , Presión Sanguínea/fisiología , Obesidad Infantil/complicaciones , Enzima Convertidora de Angiotensina 2 , Sobrepeso/complicaciones , Estudios Transversales , Peptidil-Dipeptidasa A , AngiotensinasRESUMEN
BACKGROUND: G-CSF is a critical regulator of hematopoietic cell proliferation, differentiation and survival. It has been reported that G-CSF attenuates renal injury during acute ischemia-reperfusion. In this study we evaluated the effects of G-CSF on the renal and cardiovascular systems of 2K1C hypertensive mice. METHODS: Male C57BL/6 mice were subjected to left renal artery clipping (2K1C) or sham operation and were then administered G-CSF (100 µg/kg/day) or vehicle for 14 days. RESULTS: Arterial pressure was higher in 2K1C + vehicle animals than in 2K1C + G-CSF (150±5 vs. 129±2 mmHg, p<0.01, n=8). Plasma angiotensin I, II and 1-7 concentrations were significantly increased in 2K1C + Vehicle when compared to the normotensive Sham group. G-CSF prevented the increase of these vasoactive peptides. The clipped kidney/contralateral kidney weight ratio showed a less atrophy of the ischemic kidney in the treated group (0.50±0.02 vs. 0.66±0.01, p<0.05). The infarction area in the clipped kidney was completely prevented in 7 out of 8 2K1C + G-CSF mice. Administration of G-CSF protected the clipped kidney from apoptosis. CONCLUSION: Our data indicate that G-CSF prevents kidney infarction and markedly attenuates the increases in plasma angiotensin levels and hypertension in 2K1C mice, reinforcing the protective effect of G-CSF on kidney ischemia.
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Factor Estimulante de Colonias de Granulocitos/farmacología , Hipertensión Renovascular/prevención & control , Enfermedades Renales/prevención & control , Riñón/efectos de los fármacos , Angiotensina I/sangre , Angiotensina II/sangre , Animales , Hemodinámica/efectos de los fármacos , Riñón/lesiones , Riñón/patología , Enfermedades Renales/patología , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: The hypothalamus plays a pivotal role in numerous mechanisms highly relevant to the maintenance of body homeostasis, such as the control of food intake and energy expenditure. Impairment of these mechanisms has been associated with the metabolic disturbances involved in the pathogenesis of obesity. Since rodent species constitute important models for metabolism studies and the rat hypothalamus is poorly characterized by proteomic strategies, we performed experiments aimed at constructing a two-dimensional gel electrophoresis (2-DE) profile of rat hypothalamus proteins. RESULTS: As a first step, we established the best conditions for tissue collection and protein extraction, quantification and separation. The extraction buffer composition selected for proteome characterization of rat hypothalamus was urea 7 M, thiourea 2 M, CHAPS 4%, Triton X-100 0.5%, followed by a precipitation step with chloroform/methanol. Two-dimensional (2-D) gels of hypothalamic extracts from four-month-old rats were analyzed; the protein spots were digested and identified by using tandem mass spectrometry and database query using the protein search engine MASCOT. Eighty-six hypothalamic proteins were identified, the majority of which were classified as participating in metabolic processes, consistent with the finding of a large number of proteins with catalytic activity. Genes encoding proteins identified in this study have been related to obesity development. CONCLUSION: The present results indicate that the 2-DE technique will be useful for nutritional studies focusing on hypothalamic proteins. The data presented herein will serve as a reference database for studies testing the effects of dietary manipulations on hypothalamic proteome. We trust that these experiments will lead to important knowledge on protein targets of nutritional variables potentially able to affect the complex central nervous system control of energy homeostasis.
RESUMEN
To investigate the antihypertensive effects of conventional resistance exercise (RE) on the blood pressure (BP) of hypertensive subjects, 15 middle-aged (46 ± 3 years) hypertensive volunteers, deprived of antihypertensive medication (reaching 153 ± 6/93 ± 2 mm Hg systolic/diastolic BP after a 6-week medication washout period) were submitted to a 12-week conventional RE training program (3 sets of 12 repetitions at 60% 1 repetition maximum, 3 times a week on nonconsecutive days). Blood pressure was measured in all phases of the study (washout, training, detraining). Additionally, the plasma levels of several vasodilators or vasoconstrictors that potentially could be involved with the effects of RE on BP were evaluated pre- and posttraining. Conventional RE significantly reduced systolic, diastolic, and mean BP, respectively, by an average of 16 (p < 0.001), 12 (p < 0.01), and 13 mm Hg (p < 0.01) to prehypertensive values. There were no significant changes of vasoactive factors from the kallikrein-kinin or renin-angiotensin systems. After the RE training program, the BP values remained stable during a 4-week detraining period. Taken together, this study shows for the first time that conventional moderate-intensity RE alone is able to reduce the BP of stage 1 hypertensive subjects free of antihypertensive medication. Moreover, the benefits of BP reduction achieved with RE training remained unchanged for up to 4 weeks without exercise.
Asunto(s)
Presión Sanguínea/fisiología , Hipertensión/fisiopatología , Entrenamiento de Fuerza , Adulto , Antihipertensivos/administración & dosificación , Antihipertensivos/sangre , Electrocardiografía , Humanos , Hipertensión/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
Alterations in the balance between ANG II/ACE and ANG 1-7/ACE2 in ANG II-dependent hypertension could reduce the generation of ANG 1-7 and contribute further to increased intrarenal ANG II. Upregulation of collecting duct (CD) renin may lead to increased ANG II formation during ANG II-dependent hypertension, thus contributing to this imbalance. We measured ANG I, ANG II, and ANG 1-7 contents, angiotensin-converting enzyme (ACE) and ACE2 gene expression, and renin activity in the renal cortex and medulla in the clipped kidneys (CK) and nonclipped kidneys (NCK) of 2K1C rats. After 3 wk of unilateral renal clipping, systolic blood pressure and plasma renin activity increased in 2K1C rats (n = 11) compared with sham rats (n = 9). Renal medullary angiotensin peptide levels were increased in 2K1C rats [ANG I: (CK = 171 ± 4; NCK = 251 ± 8 vs. sham = 55 ± 3 pg/g protein; P < 0.05); ANG II: (CK = 558 ± 79; NCK = 328 ± 18 vs. sham = 94 ± 7 pg/g protein; P < 0.001)]; and ANG 1-7 levels decreased (CK = 18 ± 2; NCK = 19 ± 2 pg/g vs. sham = 63 ± 10 pg/g; P < 0.001). In renal medullas of both kidneys of 2K1C rats, ACE mRNA levels and activity increased but ACE2 decreased. In further studies, we compared renal ACE and ACE2 mRNA levels and their activities from chronic ANG II-infused (n = 6) and sham-operated rats (n = 5). Although the ACE mRNA levels did not differ between ANG II rats and sham rats, the ANG II rats exhibited greater ACE activity and reduced ACE2 mRNA levels and activity. Renal medullary renin activity was similar in the CK and NCK of 2K1C rats but higher compared with sham. Thus, the differential regulation of ACE and ACE2 along with the upregulation of CD renin in both the CK and NCK in 2K1C hypertensive rats indicates that they are independent of perfusion pressure and contribute to the altered content of intrarenal ANG II and ANG 1-7.
Asunto(s)
Angiotensina II/metabolismo , Angiotensina I/metabolismo , Hipertensión Renovascular/metabolismo , Túbulos Renales Colectores/metabolismo , Riñón/metabolismo , Fragmentos de Péptidos/metabolismo , Peptidil-Dipeptidasa A/metabolismo , Renina/metabolismo , Enzima Convertidora de Angiotensina 2 , Animales , Presión Sanguínea/fisiología , Modelos Animales de Enfermedad , Corteza Renal/metabolismo , Médula Renal/metabolismo , Masculino , ARN Mensajero/metabolismo , RatasRESUMEN
Type 1 diabetes (T1DM) is a chronic disease characterized by hyperglycemia due to a deficiency in endogenous insulin production, resulting from pancreatic beta cell death. Persistent hyperglycemia leads to enhanced oxidative stress and liver injury. Several studies have evaluated the anti-diabetic and protective effects of probiotic strains in animal models. In the present study, we investigated, through histopathological and biochemical analyses, the effects of eight weeks of administration of Saccharomyces boulardii (S. boulardii) yeast on the liver of streptozotocin (STZ) induced diabetic C57BL/6 mice. Our results demonstrated that S. boulardii attenuates hepatocytes hydropic degeneration and hepatic vessels congestion in STZ-induced diabetic mice. The treatment attenuated the oxidative stress in diabetic mice leading to a reduction of carbonylated protein concentration and increased activity of antioxidant enzymes superoxide dismutase and glutathione peroxidase, compared to untreated diabetic animals. The results also show the beneficial influence of S. boulardii in regulating the hepatic concentration of renin angiotensin system (RAS) peptides. Therefore, our results demonstrated that S. boulardii administration to STZ-induced diabetic mice reduces oxidative stress and normalizes the concentration of RAS peptides, supporting the hypothesis that this yeast may have a role as a potential adjunctive therapy to attenuate diabetes-induced liver injury.
Asunto(s)
Diabetes Mellitus Experimental/complicaciones , Hepatopatías/etiología , Hepatopatías/terapia , Sistema Renina-Angiotensina/fisiología , Saccharomyces boulardii , Alanina Transaminasa/sangre , Angiotensinas/metabolismo , Animales , Antioxidantes/metabolismo , Aspartato Aminotransferasas/sangre , Glucemia/metabolismo , Peso Corporal , Diabetes Mellitus Experimental/fisiopatología , Diabetes Mellitus Experimental/terapia , Hepatocitos/patología , Peroxidación de Lípido , Masculino , Ratones Endogámicos C57BL , Estrés Oxidativo , EstreptozocinaRESUMEN
High salt intake is a known cardiovascular risk factor and is associated with cardiac alterations. To better understand this effect, male Wistar rats were fed a normal (NSD: 1.3% NaCl), high 4 (HSD4: 4%), or high 8 (HSD8: 8%) salt diet from weaning until 18 wk of age. The HSD8 group was subdivided into HSD8, HSD8+HZ (15 mg . kg(-1) . d(-1) hydralazine in the drinking water), and HSD8+LOS (20 mg . kg(-1) . d(-1) losartan in the drinking water) groups. The cardiomyocyte diameter was greater in the HSD4 and HSD8 groups than in the HSD8+LOS and NSD groups. Interstitial fibrosis was greater in the HSD4 and HSD8 groups than in the HSD8+HZ and NSD groups. Hydralazine prevented high blood pressure (BP) and fibrosis, but not cardiomyocyte hypertrophy. Losartan prevented high BP and cardiomyocyte hypertrophy, but not fibrosis. Angiotensin II type 1 receptor (AT(1)) protein expression in both ventricles was greater in the HSD8 group than in the NSD group. Losartan, but not hydralazine, prevented this effect. Compared with the NSD group, the binding of an AT(1) conformation-specific antibody that recognizes the activated form of the receptor was lower in both ventricles in all other groups. Losartan further lowered the binding of the anti-AT(1) antibody in both ventricles compared with all other experimental groups. Angiotensin II was greater in both ventricles in all groups compared with the NSD group. Myocardial structural alterations in response to HSD are independent of the effect on BP. Salt-induced cardiomyocyte hypertrophy and interstitial fibrosis possibly are due to different mechanisms. Evidence from the present study suggests that salt-induced AT(1) receptor internalization is probably due to angiotensin II binding.
Asunto(s)
Presión Sanguínea/fisiología , Cardiomegalia/inducido químicamente , Cardiomegalia/fisiopatología , Miocardio/patología , Cloruro de Sodio Dietético/administración & dosificación , Aldosterona/sangre , Angiotensina II/análisis , Bloqueadores del Receptor Tipo 1 de Angiotensina II/administración & dosificación , Animales , Antihipertensivos/administración & dosificación , Cardiomegalia/patología , Colágeno Tipo I/análisis , Colágeno Tipo III/análisis , Modelos Animales de Enfermedad , Ingestión de Líquidos , Ingestión de Alimentos , Ecocardiografía , Fibrosis , Expresión Génica , Ventrículos Cardíacos/química , Ventrículos Cardíacos/patología , Hidralazina/administración & dosificación , Hipertensión/fisiopatología , Hipertensión/prevención & control , Losartán/administración & dosificación , Masculino , Potasio/sangre , Ratas , Ratas Wistar , Receptor de Angiotensina Tipo 1/análisis , Receptor de Angiotensina Tipo 1/genética , Receptor de Angiotensina Tipo 1/fisiología , Receptor de Angiotensina Tipo 2/análisis , Renina/sangre , Sistema Renina-Angiotensina/genética , Sistema Renina-Angiotensina/fisiología , Sodio/sangre , Sodio/orina , Factor de Crecimiento Transformador beta/análisis , OrinaRESUMEN
Hypothalamic serotonin inhibits food intake and stimulates energy expenditure. High-fat feeding is obesogenic, but the role of polyunsaturated fats is not well understood. This study examined the influence of different high-PUFA diets on serotonin-induced hypophagia, hypothalamic serotonin turnover, and hypothalamic protein levels of serotonin transporter (ST), and SR-1B and SR-2C receptors. Male Wistar rats received for 9 weeks from weaning a diet high in either soy oil or fish oil or low fat (control diet). Throughout 9 weeks, daily intake of fat diets decreased such that energy intake was similar to that of the control diet. However, the fish group developed heavier retroperitoneal and epididymal fat depots. After 12 h of either 200 or 300 µg intracerebroventricular serotonin, food intake was significantly inhibited in control group (21-25%) and soy group (37-39%) but not in the fish group. Serotonin turnover was significantly lower in the fish group than in both the control group (-13%) and the soy group (-18%). SR-2C levels of fish group were lower than those of control group (50%, P = 0.02) and soy group (37%, P = 0.09). ST levels tended to decrease in the fish group in comparison to the control group (16%, P = 0.339) and the soy group (21%, P = 0.161). Thus, unlike the soy-oil diet, the fish-oil diet decreased hypothalamic serotonin turnover and SR-2C levels and abolished serotonin-induced hypophagia. Fish-diet rats were potentially hypophagic, suggesting that, at least up to this point in its course, the serotonergic impairment was either compensated by other factors or not of a sufficient extent to affect feeding. That fat pad weight increased in the absence of hyperphagia indicates that energy expenditure was affected by the serotonergic hypofunction.
Asunto(s)
Grasas Insaturadas en la Dieta/farmacología , Ingestión de Alimentos/efectos de los fármacos , Aceites de Pescado/farmacología , Serotonina/metabolismo , Tejido Adiposo/anatomía & histología , Animales , Dieta , Aceites de Pescado/administración & dosificación , Humanos , Ácido Hidroxiindolacético/química , Ácido Hidroxiindolacético/metabolismo , Hipotálamo/química , Hipotálamo/metabolismo , Infusiones Intraventriculares , Masculino , Tamaño de los Órganos , Distribución Aleatoria , Ratas , Ratas Wistar , Receptor de Serotonina 5-HT1B/metabolismo , Receptor de Serotonina 5-HT2C/metabolismo , Serotonina/administración & dosificación , Serotonina/química , Proteínas de Transporte de Serotonina en la Membrana Plasmática/metabolismo , Aceite de Soja/administración & dosificación , Aceite de Soja/farmacologíaRESUMEN
1. Impairmant of baroreflex sensitivity (BRS) has been implicated in the reduction of heart rate variability (HRV) and in the increased risk of death after myocardial infarction (MI). In the present study, we investigated whether the additional impairment in BRS induced by sinoaortic baroreceptor denervation (SAD) in MI rats is associated with changes in the low-frequency (LF) component of HRV and increased mortality rate. 2. Rats were randomly divided into four groups: control, MI, denervated (SAD) and SAD + MI rats. Left ventricular (LV) function was evaluated by echocardiography. Autonomic components were assessed by power spectral analysis and BRS. 3. Myocardial infarction (90 days) reduced ejection fraction (by approximately 42%) in both the MI and SAD + MI groups; however, an increase in LV mass and diastolic dysfunction were observed only in the SAD + MI group. Furthermore, BRS, HRV and the LF power of HRV were reduced after MI, with an exacerbated reduction seen in SAD + MI rats. The LF component of blood pressure variability (BPV) was increased in the MI, SAD and SAD + MI groups compared with the control group. Mortality was higher in the MI groups compared with the non-infarcted groups, with an additional increase in mortality in the SAD + MI group compared with the MI group. Correlations were obtained between BRS and the LF component of HRV and between LV mass and the LF component of BPV. 4. Together, the results indicate that the abolishment of BRS induced by SAD in MI rats further reduces the LF band of HRV, resulting in a worse cardiac remodelling and increased mortality in these rats. These data highlight the importance of this mechanism in the prognosis of patients after an ischaemic event.