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1.
Sci Rep ; 13(1): 8741, 2023 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-37253814

RESUMO

Epidemiologic data suggest that the prevalence of hypertension in patients with diabetes mellitus is ∼1.5-2.0 times greater than in matched non-diabetic patients. This co-existent disease burden exacerbates cardiac and vascular injury, leading to structural and functional changes to the myocardium, impaired cardiac function and heart failure. Oxidative stress and persistent low-grade inflammation underlie both conditions, and are identified as major contributors to pathological cardiac remodelling. There is an urgent need for effective therapies that specifically target oxidative stress and inflammation to protect against cardiac remodelling. Animal models are a valuable tool for testing emerging therapeutics, however, there is a notable lack of appropriate animal models of co-morbid diabetes and hypertension. In this study, we describe a novel preclinical mouse model combining diabetes and hypertension to investigate cardiac and vascular pathology of co-morbid disease. Type 1 diabetes was induced in spontaneously hypertensive, 8-week old, male Schlager (BPH/2) mice via 5 consecutive, daily injections of streptozotocin (55 mg/kg in citrate buffer; i.p.). Non-diabetic mice received citrate buffer only. After 10 weeks of diabetes induction, cardiac function was assessed by echocardiography prior to post-mortem evaluation of cardiomyocyte hypertrophy, interstitial fibrosis and inflammation by histology, RT-PCR and flow cytometry. We focussed on the oxidative and inflammatory stress pathways that contribute to cardiovascular remodelling. In particular, we demonstrate that markers of inflammation (monocyte chemoattractant protein; MCP-1), oxidative stress (urinary 8-isoprostanes) and fibrosis (connective tissue growth factor; CTGF) are significantly increased, whilst diastolic dysfunction, as indicated by prolonged isovolumic relaxation time (IVRT), is elevated in this diabetic and hypertensive mouse model. In summary, this pre-clinical mouse model provides researchers with a tool to test therapeutic strategies unique to co-morbid diabetes and hypertension, thereby facilitating the emergence of novel therapeutics to combat the cardiovascular consequences of these debilitating co-morbidities.


Assuntos
Diabetes Mellitus , Cardiomiopatias Diabéticas , Hipertensão , Masculino , Camundongos , Animais , Remodelação Ventricular , Miocárdio/metabolismo , Hipertensão/patologia , Modelos Animais de Doenças , Estresse Oxidativo , Fibrose , Inflamação/patologia , Morbidade , Citratos/farmacologia , Cardiomiopatias Diabéticas/patologia , Diabetes Mellitus/metabolismo
2.
Sci Rep ; 12(1): 11570, 2022 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-35798762

RESUMO

Atherosclerosis and its complications are major causes of cardiovascular morbidity and death. Apart from risk factors such as hypercholesterolemia and inflammation, the causal molecular mechanisms are unknown. One proposed causal mechanism involves elevated levels of reactive oxygen species (ROS). Indeed, early expression of the ROS forming NADPH oxidase type 5 (Nox5) in vascular endothelial cells correlates with atherosclerosis and aortic aneurysm. Here we test the pro-atherogenic Nox5 hypothesis using mouse models. Because Nox5 is missing from the mouse genome, a knock-in mouse model expressing human Nox5 in its physiological location of endothelial cells (eNOX5ki/ki) was tested as a possible new humanised mouse atherosclerosis model. However, whether just on a high cholesterol diet or by crossing in aortic atherosclerosis-prone ApoE-/- mice with and without induction of diabetes, Nox5 neither induced on its own nor aggravated aortic atherosclerosis. Surprisingly, however, diabetic ApoE-/- x eNOX5ki/ki mice developed aortic aneurysms more than twice as often correlating with lower vascular collagens, as assessed by trichrome staining, without changes in inflammatory gene expression, suggesting that endothelial Nox5 directly affects extracellular matrix remodelling associated with aneurysm formation in diabetes. Thus Nox5-derived reactive oxygen species are not a new independent mechanism of atherosclerosis but may enhance the frequency of abdominal aortic aneurysms in the context of diabetes. Together with similar clinical findings, our preclinical target validation opens up a first-in-class mechanism-based approach to treat or even prevent abdominal aortic aneurysms.


Assuntos
Aneurisma da Aorta Abdominal , Aterosclerose , Diabetes Mellitus , NADPH Oxidase 5 , Animais , Aterosclerose/metabolismo , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Camundongos , Camundongos Knockout para ApoE , NADPH Oxidase 5/metabolismo , Oxigênio , Espécies Reativas de Oxigênio/metabolismo
7.
Hypertension ; 76(5): 1470-1479, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32895021

RESUMO

Overactivity of the sympathetic nervous system and high blood pressure are implicated in the development and progression of chronic kidney disease (CKD) and independently predict cardiovascular events in end-stage renal disease. To assess the role of renal nerves, we determined whether renal denervation (RDN) altered the hypertension and sympathoexcitation associated with a rabbit model of CKD. The model involves glomerular layer lesioning and uninephrectomy, resulting in renal function reduced by one-third and diuresis. After 3-week CKD, blood pressure was 13±2 mm Hg higher than at baseline (P<0.001), and compared with sham control rabbits, renal sympathetic nerve activity was 1.2±0.5 normalized units greater (P=0.01). The depressor response to ganglion blockade was also +8.0±3 mm Hg greater, but total norepinephrine spillover was 8.7±3.7 ng/min lower (both P<0.05). RDN CKD rabbits only increased blood pressure by 8.0±1.5 mm Hg. Renal sympathetic activity, the response to ganglion blockade and diuresis were similar to sham denervated rabbits (non-CKD). CKD rabbits had intact renal sympathetic baroreflex gain and range, as well as normal sympathetic responses to airjet stress. However, hypoxia-induced sympathoexcitation was reduced by -9±0.4 normalized units. RDN did not alter the sympathetic response to hypoxia or airjet stress. CKD increased oxidative stress markers Nox5 and MCP-1 (monocyte chemoattractant protein-1) in the kidney, but RDN had no effect on these measures. Thus, RDN is an effective treatment for hypertension in this model of CKD without further impairing renal function or altering the normal sympathetic reflex responses to various environmental stimuli.


Assuntos
Pressão Sanguínea/fisiologia , Hipertensão/fisiopatologia , Rim/inervação , Insuficiência Renal Crônica/fisiopatologia , Insuficiência Renal/fisiopatologia , Animais , Barorreflexo/fisiologia , Denervação , Modelos Animais de Doenças , Rim/fisiopatologia , Masculino , Coelhos , Simpatectomia
8.
Kidney Int ; 98(4): 906-917, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32763117

RESUMO

Chronic kidney disease (CKD) is associated with greater sympathetic nerve activity but it is unclear if this is a kidney-specific response or due to generalized stimulation of sympathetic nervous system activity. To determine this, we used a rabbit model of CKD in which quantitative comparisons with control rabbits could be made of kidney sympathetic nerve activity and whole-body norepinephrine spillover. Rabbits either had surgery to lesion 5/6th of the cortex of one kidney by electro-lesioning and two weeks later removal of the contralateral kidney, or sham lesioning and sham nephrectomy. After three weeks, the blood pressure was statistically significantly 20% higher in conscious rabbits with CKD compared to rabbits with a sham operation, but their heart rate was similar. Strikingly, kidney nerve activity was 37% greater than in controls, with greater burst height and frequency. Total norepinephrine spillover was statistically significantly lower by 34%, and kidney baroreflex curves were shifted to the right in rabbits with CKD. Plasma creatinine and urine output were elevated by 38% and 131%, respectively, and the glomerular filtration rate was 37% lower than in sham-operated animals (all statistically significant). Kidney gene expression of fibronectin, transforming growth factor-ß, monocyte chemotactic protein1, Nox4 and Nox5 was two- to eight-fold greater in rabbits with CKD than in control rabbits. Overall, the glomerular layer lesioning model in conscious rabbits produced a moderate, stable degree of CKD characterized by elevated blood pressure and increased kidney sympathetic nerve activity. Thus, our findings, together with that of a reduction in total norepinephrine spillover, suggest that kidney denervation, rather than generalized sympatholytic treatments, may represent a preferable management for CKD associated hypertension.


Assuntos
Insuficiência Renal Crônica , Animais , Barorreflexo , Pressão Sanguínea , Frequência Cardíaca , Rim , Coelhos , Sistema Nervoso Simpático
9.
Front Physiol ; 11: 518, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581831

RESUMO

It is well established that diabetes is the major cause of chronic kidney disease worldwide. Both hyperglycemia, and more recently, advanced glycation endproducts, have been shown to play critical roles in the development of kidney disease. Moreover, the renin-angiotensin system along with growth factors and cytokines have also been shown to contribute to the onset and progression of diabetic kidney disease; however, the role of lipids in this context is poorly characterized. The current study aimed to compare the effect of 20 weeks of streptozotocin-induced diabetes or western diet feeding on kidney disease in two different mouse strains, C57BL/6 mice and hyperlipidemic apolipoprotein (apo) E knockout (KO) mice. Mice were fed a chow diet (control), a western diet (21% fat, 0.15% cholesterol) or were induced with streptozotocin-diabetes (55 mg/kg/day for 5 days) then fed a chow diet and followed for 20 weeks. The induction of diabetes was associated with a 3-fold elevation in glycated hemoglobin and an increase in kidney to body weight ratio regardless of strain (p < 0.0001). ApoE deficiency significantly increased plasma cholesterol and triglyceride levels and feeding of a western diet exacerbated these effects. Despite this, urinary albumin excretion (UAE) was elevated in diabetic mice to a similar extent in both strains (p < 0.0001) but no effect was seen with a western diet in either strain. Diabetes was also associated with extracellular matrix accumulation in both strains, and western diet feeding to a lesser extent in apoE KO mice. Consistent with this, an increase in renal mRNA expression of the fibrotic marker, fibronectin, was observed in diabetic C57BL/6 mice (p < 0.0001). In summary, these studies demonstrate disparate effects of diabetes and hyperlipidemia on kidney injury, with features of the diabetic milieu other than lipids suggested to play a more prominent role in driving renal pathology.

10.
Diabetologia ; 63(7): 1424-1434, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32372207

RESUMO

AIMS/HYPOTHESIS: We determined whether empagliflozin altered renal sympathetic nerve activity (RSNA) and baroreflexes in a diabetes model in conscious rabbits. METHODS: Diabetes was induced by alloxan, and RSNA, mean arterial pressure (MAP) and heart rate were measured before and after 1 week of treatment with empagliflozin, insulin, the diuretic acetazolamide or the ACE inhibitor perindopril, or no treatment, in conscious rabbits. RESULTS: Four weeks after alloxan administration, blood glucose was threefold and MAP 9% higher than non-diabetic controls (p < 0.05). One week of treatment with empagliflozin produced a stable fall in blood glucose (-43%) and increased water intake (+49%) but did not change RSNA, MAP or heart rate compared with untreated diabetic rabbits. The maximum RSNA to hypotension was augmented by 75% (p < 0.01) in diabetic rabbits but the heart rate baroreflex was unaltered. Empagliflozin and acetazolamide reduced the augmentation of the RSNA baroreflex (p < 0.05) to be similar to the non-diabetic group. Noradrenaline (norepinephrine) spillover was similar in untreated diabetic and non-diabetic rabbits but twofold greater in empagliflozin- and acetazolamide-treated rabbits (p < 0.05). CONCLUSIONS/INTERPRETATION: As empagliflozin can restore diabetes-induced augmented sympathetic reflexes, this may be beneficial in diabetic patients. A similar action of the diuretic acetazolamide suggests that the mechanism may involve increased sodium and water excretion. Graphical abstract.


Assuntos
Compostos Benzidrílicos/uso terapêutico , Glucosídeos/uso terapêutico , Animais , Barorreflexo/efeitos dos fármacos , Glicemia/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Masculino , Perindopril/farmacologia , Coelhos , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/metabolismo
11.
Front Physiol ; 10: 1395, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31798462

RESUMO

The increasing burden of heart failure globally can be partly attributed to the increased prevalence of diabetes, and the subsequent development of a distinct form of heart failure known as diabetic cardiomyopathy. Despite this, effective treatment options have remained elusive, due partly to the lack of an experimental model that adequately mimics human disease. In the current study, we combined three consecutive daily injections of low-dose streptozotocin with high-fat diet, in order to recapitulate the long-term complications of diabetes, with a specific focus on the diabetic heart. At 26 weeks of diabetes, several metabolic changes were observed including elevated blood glucose, glycated haemoglobin, plasma insulin and plasma C-peptide. Further analysis of organs commonly affected by diabetes revealed diabetic nephropathy, underlined by renal functional and structural abnormalities, as well as progressive liver damage. In addition, this protocol led to robust left ventricular diastolic dysfunction at 26 weeks with preserved systolic function, a key characteristic of patients with type 2 diabetes-induced cardiomyopathy. These observations corresponded with cardiac structural changes, namely an increase in myocardial fibrosis, as well as activation of several cardiac signalling pathways previously implicated in disease progression. It is hoped that development of an appropriate model will help to understand some the pathophysiological mechanisms underlying the accelerated progression of diabetic complications, leading ultimately to more efficacious treatment options.

12.
Front Physiol ; 10: 309, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31040788

RESUMO

Patients with diabetic hypertensive nephropathy have accelerated disease progression. Diabetes and hypertension have both been associated with changes in renal catecholamines and reactive oxygen species. With a specific focus on renal catecholamines and oxidative stress we examined a combined model of hypertension and diabetes using normotensive BPN/3J and hypertensive BPH/2J Schlager mice. Induction of diabetes (5 × 55 mg/kg streptozotocin i.p.) did not change the hypertensive status of BPH/2J mice (telemetric 24 h avg. MAP, non-diabetic 131 ± 2 vs. diabetic 129 ± 1 mmHg, n.s at 9 weeks of study). Diabetes-associated albuminuria was higher in BPH/2J vs. diabetic BPN/3J (1205 + 196/-169 versus 496 + 67/-59 µg/24 h, p = 0.008). HPLC measurement of renal cortical norepinephrine and dopamine showed significantly greater levels in hypertensive mice whilst diabetes was associated with significantly lower catecholamine levels. Diabetic BPH/2J also had greater renal catecholamine levels than diabetic BPN/3J (diabetic: norepinephrine BPN/3J 40 ± 4, BPH/2J 91 ± 5, p = 0.010; dopamine: BPN/3J 2 ± 1; BPH/2J 3 ± 1 ng/mg total protein, p < 0.001 after 10 weeks of study). Diabetic BPH/2J showed greater cortical tubular immunostaining for monoamine oxidase A and cortical mitochondrial hydrogen peroxide formation was greater in both diabetic and non-diabetic BPH/2J. While cytosolic catalase activity was greater in non-diabetic BPH/2J it was significantly lower in diabetic BPH/2J (cytosolic: BPH/2J 127 ± 12 vs. 63 ± 6 nmol/min/ml, p < 0.001). We conclude that greater levels of renal norepinephrine and dopamine associated with hypertension, together with diabetes-associated compromised anti-oxidant systems, contribute to increased renal oxidative stress in diabetes and hypertension. Elevations in renal cortical catecholamines and reactive oxygen species have important therapeutic implications for hypertensive diabetic patients.

13.
Curr Diabetes Rev ; 15(5): 349-356, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29663893

RESUMO

BACKGROUND: The sodium glucose co-transporter 2 (SGLT2) is primarily located within S1 of the renal proximal tubule being responsible for approximately 90% of glucose re-uptake in the kidney. Inhibition of SGLT2 is an exciting new pharmacological approach for the reduction of blood glucose in type 2 diabetic patients via inhibition of tubular glucose reabsorption. In addition to lowering glucose, this group of drugs has shown significant cardiovascular and renal protective effects. CONCLUSION: This review aims to outline the current state of preclinical research and clinical trials for different SGLT2 inhibitors and outline some of the proposed mechanisms of action, including possible effects on sympathetic nerve activity, which may contribute to the unexpected beneficial cardiovascular and reno-protective effects of this class of compounds.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Nefropatias , Inibidores do Transportador 2 de Sódio-Glicose , Glicemia , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Humanos , Hipoglicemiantes , Nefropatias/complicações , Nefropatias/prevenção & controle , Transportador 2 de Glucose-Sódio , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico
14.
Clin Sci (Lond) ; 131(10): 981-990, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28473473

RESUMO

Oxidative stress is a consequence of up-regulation of pro-oxidant enzyme-induced reactive oxygen species (ROS) production and concomitant depletion of antioxidants. Elevated levels of ROS act as an intermediate and are the common denominator for various diseases including diabetes-associated macro-/micro-vascular complications and hypertension. A range of enzymes are capable of generating ROS, but the pro-oxidant enzyme family, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), are the only enzymes known to be solely dedicated to ROS generation in the vascular tissues, kidney, aortas and eyes. While there is convincing evidence for a role of NOX1 in vascular and eye disease and for NOX4 in renal injury, the role of NOX5 in disease is less clear. Although NOX5 is highly up-regulated in humans in disease, it is absent in rodents. Thus, so far it has not been possible to study NOX5 in traditional mouse or rat models of disease. In the present review, we summarize and critically analyse the emerging evidence for a pathophysiological role of NOX5 in disease including the expression, regulation and molecular and cellular mechanisms which have been demonstrated to be involved in NOX5 activation.


Assuntos
Proteínas de Membrana/metabolismo , NADPH Oxidases/metabolismo , Doenças Vasculares/enzimologia , Animais , Endotélio Vascular/enzimologia , Humanos , Proteínas de Membrana/genética , Camundongos , NADPH Oxidase 5 , NADPH Oxidases/genética , Ratos , Espécies Reativas de Oxigênio/metabolismo , Doenças Vasculares/genética
15.
Eur J Pharmacol ; 807: 12-20, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28438648

RESUMO

Endoplasmic reticulum (ER) stress contributes to progression of diabetic nephropathy, which promotes end-stage renal failure in diabetic patients. This study was undertaken to investigate the actions of tempol and ramipril, pharmacological agents that target the consequences of NADPH oxidase, on diabetic nephropathy in a rat model of type 1 diabetes, with an emphasis on markers of ER stress. Male Sprague-Dawley rats were injected intravenously with a single bolus of streptozotocin (55mg/kg) to induce type 1 diabetes. An additional age-matched group of rats was administered with citrate vehicle as controls. After 4 weeks of untreated diabetes, rats received tempol (1.5mM/kg/day subcutaneously, n=8), ramipril (1mg/kg/day in drinking water, n=8) or remained untreated for an additional 4 weeks (n=7). After 8 weeks of diabetes in total, kidneys were collected for histological analysis, gene expression and protein abundance. Tempol and ramipril blunted diabetes-induced upregulation of NADPH oxidase isoforms (Nox4, Nox2, p47phox), accompanied by an amelioration of diabetes-induced glomerular injury (podocin, nephrin, Kim-1), tubulo-interstitial fibrosis (TGFß1, TGFß-R2, pSMAD3, α-SMA) and pro-inflammatory cytokines (TNFα, MCP-1, ANX-A1, FPR2) expression. In addition, the diabetes-induced renal ER stress, evidenced by increased expression of GRP-78 chaperone and stress-associated markers ATF4, TRB3, as well as XBP1s, phospho-p38 mitogen-activated protein kinase (MAPK) and 3-nitrotyrosination, were all attenuated by tempol and ramipril. These observations suggest that antioxidant approaches that blunt NADPH upregulation may attenuate diabetic nephropathy, at least in part by negatively regulating ER stress and inflammation, and hence ameliorating kidney damage.


Assuntos
Materiais Biomiméticos/farmacologia , Óxidos N-Cíclicos/farmacologia , Nefropatias Diabéticas/tratamento farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , NADPH Oxidases/metabolismo , Superóxido Dismutase/metabolismo , Regulação para Cima/efeitos dos fármacos , Animais , Materiais Biomiméticos/uso terapêutico , Óxidos N-Cíclicos/uso terapêutico , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Fibrose , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/patologia , Túbulos Renais/efeitos dos fármacos , Túbulos Renais/patologia , Masculino , Óxido Nítrico/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ramipril/farmacologia , Ratos , Ratos Sprague-Dawley , Marcadores de Spin
16.
Atherosclerosis ; 235(2): 444-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24945577

RESUMO

OBJECTIVE/RATIONALE: Both the renin-angiotensin system (RAS) and the receptor for advanced glycation end products (RAGE) potentiate diabetes-associated atherosclerosis (DAA). We assessed the effectiveness of concomitant RAS and RAGE inhibition on DAA. METHODS: Diabetic (5 × 55 mg/kg streptozotocin daily) and non-diabetic male RAGE/apolipoprotein E double knockout (RAGE/apoE DKO) mice were treated with quinapril (30 mg/kg/day) for 20 weeks. At the end of the study aortic plaques were assessed. RESULTS: Diabetic RAGE/apoE DKO showed significantly less plaque area than diabetic apoE KO mice. Plaque deposition was almost abolished in quinapril treated diabetic RAGE/apoE DKOs, with significant attenuation of vascular collagen deposition, nitrotyrosine staining, and reduced macrophage infiltration. Expression of the advanced glycation end product receptor 3 (galectin 3) was also significantly reduced. CONCLUSION: Concomitant inhibition of RAS and RAGE signalling almost completely inhibited the development of experimental DAA. A dual therapeutic approach may be a superior strategy for the treatment of diabetic macrovascular disease..


Assuntos
Apolipoproteínas E/genética , Aterosclerose/tratamento farmacológico , Aterosclerose/etiologia , Receptores Imunológicos/genética , Tetra-Hidroisoquinolinas/uso terapêutico , Animais , Aorta/patologia , Diabetes Mellitus Experimental/complicações , Masculino , Camundongos Knockout , Placa Aterosclerótica/prevenção & controle , Quinapril , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/biossíntese , Sistema Renina-Angiotensina/efeitos dos fármacos
17.
Hypertension ; 62(4): 775-81, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23897069

RESUMO

Genetically hypertensive mice (BPH/2J) are hypertensive because of an exaggerated contribution of the sympathetic nervous system to blood pressure. We hypothesize that an additional contribution to elevated blood pressure is via sympathetically mediated activation of the intrarenal renin-angiotensin system. Our aim was to determine the contribution of the renin-angiotensin system and sympathetic nervous system to hypertension in BPH/2J mice. BPH/2J and normotensive BPN/3J mice were preimplanted with radiotelemetry devices to measure blood pressure. Depressor responses to ganglion blocker pentolinium (5 mg/kg i.p.) in mice pretreated with the angiotensin-converting enzyme inhibitor enalaprilat (1.5 mg/kg i.p.) revealed a 2-fold greater sympathetic contribution to blood pressure in BPH/2J mice during the active and inactive period. However, the depressor response to enalaprilat was 4-fold greater in BPH/2J compared with BPN/3J mice, but only during the active period (P=0.01). This was associated with 1.6-fold higher renal renin messenger RNA (mRNA; P=0.02) and 0.8-fold lower abundance of micro-RNA-181a (P=0.03), identified previously as regulating human renin mRNA. Renin mRNA levels correlated positively with depressor responses to pentolinium (r=0.99; P=0.001), and BPH/2J mice had greater renal sympathetic innervation density as identified by tyrosine hydroxylase staining of cortical tubules. Although there is a major sympathetic contribution to hypertension in BPH/2J mice, the renin-angiotensin system also contributes, doing so to a greater extent during the active period and less during the inactive period. This is the opposite of the normal renin-angiotensin system circadian pattern. We suggest that renal hyperinnervation and enhanced sympathetically induced renin synthesis mediated by lower micro-RNA-181a contributes to hypertension in BPH/2J mice.


Assuntos
Hipertensão/genética , MicroRNAs/genética , Sistema Renina-Angiotensina/fisiologia , Renina/sangue , Sistema Nervoso Simpático/fisiopatologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Enalaprilato/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Hipertensão/sangue , Hipertensão/fisiopatologia , Camundongos , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Antagonistas Nicotínicos/farmacologia , Tartarato de Pentolínio/farmacologia , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos
18.
Diabetes ; 61(8): 2105-13, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22698914

RESUMO

Advanced glycation end products (AGEs) are important mediators of diabetic nephropathy that act through the receptor for AGEs (RAGE), as well as other mechanisms, to promote renal inflammation and glomerulosclerosis. The relative contribution of RAGE-dependent and RAGE-independent signaling pathways has not been previously studied in vivo. In this study, diabetic RAGE apoE double-knockout (KO) mice with streptozotocin-induced diabetes were treated with the AGE inhibitor, alagebrium (1 mg/kg/day), or the ACE inhibitor, quinapril (30 mg/kg/day), for 20 weeks, and renal parameters were assessed. RAGE deletion attenuated mesangial expansion, glomerular matrix accumulation, and renal oxidative stress associated with 20 weeks of diabetes. By contrast, inflammation and AGE accumulation associated with diabetes was not prevented. However, treatment with alagebrium in diabetic RAGE apoE KO mice reduced renal AGE levels and further reduced glomerular matrix accumulation. In addition, even in the absence of RAGE expression, alagebrium attenuated cortical inflammation, as denoted by the reduced expression of monocyte chemoattractant protein-1, intracellular adhesion molecule-1, and the macrophage marker cluster of differentiation molecule 11b. These novel findings confirm the presence of important RAGE-independent as well as RAGE-dependent signaling pathways that may be activated in the kidney by AGEs. This has important implications for the design of optimal therapeutic strategies for the prevention of diabetic nephropathy.


Assuntos
Apolipoproteínas E/genética , Produtos Finais de Glicação Avançada/metabolismo , Receptores Imunológicos/metabolismo , Tiazóis/farmacologia , Albuminúria , Animais , Diabetes Mellitus Experimental , Fibrose/etiologia , Mesângio Glomerular/efeitos dos fármacos , Glomerulonefrite/etiologia , Masculino , Camundongos , Camundongos Knockout , Nefrite/etiologia , Estresse Oxidativo/fisiologia , Quinapril , Receptor para Produtos Finais de Glicação Avançada , Tetra-Hidroisoquinolinas/farmacologia
19.
Hypertension ; 59(3): 634-41, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22311902

RESUMO

In heart failure (HF), cardiac sympathetic nerve activity (SNA; CSNA) is increased, which has detrimental effects on the heart and promotes arrhythmias and sudden death. There is evidence that the central renin-angiotensin system plays an important role in stimulating renal SNA in HF. Because SNA to individual organs is differentially controlled, we have investigated whether central angiotensin receptor blockade decreases CSNA in HF. We simultaneously recorded CSNA and renal SNA in conscious normal sheep and in sheep with HF induced by rapid ventricular pacing (ejection fraction: <40%). The effect of blockade of central angiotensin type 1 receptors by intracerebroventricular infusion of losartan (1 mg/h for 5 hours) on resting levels and baroreflex control of CSNA and renal SNA were determined. In addition, the levels of angiotensin receptors in central autonomic nuclei were determined using autoradiography. Sheep in HF had a large increase in CSNA (43±2 to 88±3 bursts per 100 heart beats; P<0.05) and heart rate, with no effect on renal SNA. In HF, central infusion of losartan for 5 hours significantly reduced the baseline levels of CSNA (to 69±5 bursts per 100 heart beats) and heart rate. Losartan had no effect in normal animals. In HF, angiotensin receptor levels were increased in the paraventricular nucleus and supraoptic nucleus but reduced in the area postrema and nucleus tractus solitarius. In summary, infusion of losartan reduced the elevated levels of CNSA in an ovine model of HF, indicating that central angiotensin receptors play a critical role in stimulating the increased sympathetic activity to the heart.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Insuficiência Cardíaca/tratamento farmacológico , Coração/inervação , Rim/inervação , Losartan/administração & dosagem , Sistema Nervoso Simpático/fisiopatologia , Animais , Autorradiografia , Barorreflexo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Modelos Animais de Doenças , Insuficiência Cardíaca/fisiopatologia , Frequência Cardíaca/efeitos dos fármacos , Infusões Intravenosas , Ovinos , Sistema Nervoso Simpático/efeitos dos fármacos
20.
Curr Opin Nephrol Hypertens ; 21(1): 66-71, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22123210

RESUMO

PURPOSE OF REVIEW: There is increasing evidence that endothelin receptor blockade and, in particular, ET(A) receptor blockade not only confers protection against proteinuric renal disease in diabetes but also confers vasculoprotection. RECENT FINDINGS: Recent clinical trials using ET(A) receptor blockade in treating proteinuria and chronic kidney disease as well as atherosclerosis show great promise; however, adverse effects are still problematic. SUMMARY: Endothelin receptor blockade is associated with a significant attenuation of proteinuria and these effects are mediated in part via inhibition of inflammatory and oxidative stress related pathways as well profibrotic pathways. The addition of ET(A) receptor blockade to currently established therapies such as angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may result in additional or synergistic renoprotection and vasculoprotection in hypertension and, in particular, in the context of diabetes.


Assuntos
Fármacos Cardiovasculares/uso terapêutico , Doenças Cardiovasculares/tratamento farmacológico , Antagonistas dos Receptores de Endotelina , Endotelinas/metabolismo , Nefropatias/tratamento farmacológico , Rim/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Aterosclerose/tratamento farmacológico , Aterosclerose/metabolismo , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/metabolismo , Doença Crônica , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/metabolismo , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/metabolismo , Rim/metabolismo , Nefropatias/etiologia , Nefropatias/metabolismo , Proteinúria/tratamento farmacológico , Proteinúria/metabolismo , Receptores de Endotelina/metabolismo
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