Endothelial expression of the receptor for advanced glycation end products in experimental diabetes / Expresión endotelial del receptor para productos finales de glicación avanzada en diabetes experimental

The receptor for advanced glycation end products (RAGE) is implicated in the pathogenesis of several chronic diseases including diabetes. The interaction between RAGE and advanced glycation end products (AGEs) promotes gene expression, enhances the release of proinflammatory molecules and causes the generation of oxidative stress in numerous cell types. The aim of this investigation was to evaluate the effect of enalapril and losartan on RAGE expression in abdominal aortic endothelium of rats with experimentally induced diabetes. Male Sprague-Dawley rats, weighing approximately 150 - 200 g, were used. Diabetes was induced in 30 rats by intravenous administration of a single dose of 55 mg/kg body weight of streptozotocin (ETZ). The following groups were studied: control (n=10), diabetic (n=10), losartan-treated diabetic (n=10) and enalapril-treated diabetic (n=10) rats. RAGE expression in aortic endothelium was determined by indirect immunofluorescence. A significant increase in RAGE expression was observed in diabetic animals versus controls (p<0.001), there was a decrease in RAGE expression, in animals treated with losartan versus controls (p<0.01) and in those treated with enalapril (p<0.05) versus control and versus diabetes + vehicle. In conclusion, in the experimental model of ETZ-induced diabetes, there is an increase in RAGE expression at the level of the abdominal aortic endothelium, which can be reversed by treatment with losartan and/or enalapril, two drugs that block the renin-angiotensin system, suggesting its involvement in the molecular events related to vascular damage during diabetes.

El receptor para productos finales de glicación avanzada (RAGE) está implicado en la patogénesis de varias enfermedades crónicas incluyendo la diabetes. La interacción entre RAGE y los productos finales de glicación avanzada (AGEs), promueve la expresión génica, potencia la liberación de moléculas proinflamatorias y provoca la generación de estrés oxidativo en numerosos tipos de células. El objetivo de esta investigación fue evaluar el efecto del enalapril y el losartán sobre la expresión de RAGE en el endotelio de la aorta abdominal de ratas con diabetes inducida experimentalmente. Se utilizaron ratas Sprague-Dawley machos, con un peso aproximado de entre 150 - 200 g. La diabetes se indujo en 30 ratas mediante la administración intravenosa de una sola dosis de 55 mg/Kg de peso corporal de estreptozotocina (ETZ). Se estudiaron los siguientes grupos: ratas control (n=10), diabéticas (n=10), diabéticas tratadas con losartán (n=10) y diabéticas tratadas con enalapril (n=10). La expresión de RAGE en el endotelio aórtico se determinó por inmunofluorescencia indirecta. Se observó un incremento significativo en la expresión de RAGE en los animales diabéticos versus los controles (p<0.001), hubo una disminución en la expresión de RAGE, en los animales tratados con losartán versus los controles (p<0.01) y en los tratados con enalapril (p<0.05) versus control y versus diabetes + vehículo. En conclusión, en el modelo experimental de diabetes inducida por ETZ, existe un incremento en la expresión de RAGE a nivel del endotelio de la aorta abdominal, la cual puede revertirse mediante el tratamiento con losartán y/o enalapril, dos fármacos bloqueadores del sistema renina-angiotensina, lo cual sugiere la participación del mismo en los acontecimientos moleculares relacionados con el daño vascular durante la diabetes.

Improved histoarchitectural changes with angiotensin receptor blockers in early testicular and cauda toxicity in rats / Mejora de los cambios en la histoarquitectura con bloqueadores de receptores de angiotensina en la toxicidad precoz testicular y de cauda en ratas

SUMMARY: Reproductive dysfunction is a complication for many diseases and toxins. Its early diagnosis and treatment are immensely important. Here the morphological histoarchitecture changes in early testicular and cauda toxicity before and after treatment with angiotensin receptor blockers were evaluated. Low-grade testicular damage was induced using thioacetamide (TAA, 50 mg/kg/day) intraperitoneally for two weeks in rats. The rats were randomly divided into four groups (n = 8) treated daily orally for three weeks as follows: Normal control (distilled water), TAA (positive control), TAA+candesartan (0.2 mg/kg) and TAA+losartan (7.5 mg/kg). Serum testosterone and testicular malondialdehyde and glutathione were measured. The changes in histoarchitecture of testis and cauda epididymis were evaluated by hematoxylin and eosin for general structure, Masson's trichrome for collagen, periodic acid Schiff for basement membrane, and caspase-3 and proliferating cell nuclear antigen (PCNA) for immunohistochemical analysis. The TAA-rats showed decreases of serum testosterone and testicular glutathione, increases in testicular malondialdehyde, degenerative changes and apoptosis in germ cells, thickening of tubular basal lamina and increases in expression of caspase 3, and decreases in expression of PCNA. The ARBs (candesartan and losartan) significantly reversed these changes with non-significant differences in-between. Treatment with ARBs (candesartan and losartan) significantly reversed TAA-induced low-grade testicular and cauda toxicity in rats. This could be potentially useful for early treatment of male patients with occupational toxicant-induced reproductive dysfunction especially if they are using ARBs for other comorbidities.

RESUMEN: La disfunción reproductiva es una complicación por muchas enfermedades y toxinas. Su diagnóstico y tratamiento tempranos son inmensamente importantes. Aquí se evaluaron los cambios morfológicos en la histoarquitectura en la toxicidad precoz testicular y cauda antes y después del tratamiento con bloqueadores de receptores de angiotensina. Se indujo daño testicular de bajo grado usando tioacetamida (TAA, 50 mg / kg / día) por vía intraperitoneal durante dos semanas en ratas. Las ratas se dividieron aleatoriamente en cuatro grupos (n = 8) tratados diariamente por vía oral durante tres semanas de la siguiente manera: control normal (agua destilada), TAA (control positivo), TAA + candesartan (0,2 mg / kg) y TAA + losartán (7,5 mg / kg). Se midieron la testosterona sérica, el malondialdehído testicular y el glutatión. Los cambios en la histoarquitectura de los testículos y la epidermis de la cauda se evaluaron mediante Hematoxilina y Eosina para determinar la estructura general, con tricrómicro de Masson para el colágeno, ácido periódico de Schiff para la membrana basal y la caspasa-3 y el antígeno nuclear de células proliferantes (PCNA) para análisis inmunohistoquímico. Las ratas TAA mostraron disminución de la testosterona sérica y glutatión testicular, aumentos en el malondialdehído testicular, cambios degenerativos y apoptosis en células germinales, engrosamiento de la lámina basal tubular y aumentos en la expresión de la caspasa 3, y disminución en la expresión de PCNA. Los ARB (candesartán y losartán) revirtieron significativamente estos cambios con diferencias no significativas en el medio. El tratamiento con BRA (candesartán y losartán) revirtió significativamente la toxicidad testicular y cauda inducida por TAA en ratas. Esto podría ser potencialmente útil para el tratamiento temprano de pacientes con disfunción reproductiva inducida por tóxicos ocupacionales, especialmente si están usando BRA para otras comorbilidades.

Participation of hepatic α/β-adrenoceptors and AT1 receptors in glucose release and portal hypertensive response induced by adrenaline or angiotensin II

It has been previously demonstrated that the hemodynamic effect induced by angiotensin II (AII) in the liver was completely abolished by losartan while glucose release was partially affected by losartan. Angiotensin II type 1 (AT1) and adrenergic (∝1- and β-) receptors (AR) belong to the G-proteins superfamily, which signaling promote glycogen breakdown and glucose release. Interactive relationship between AR and AT1-R was shown after blockade of these receptors with specific antagonists. The isolated perfused rat liver was used to study hemodynamic and metabolic responses induced by AII and adrenaline (Adr) in the presence of AT1 (losartan) and ∝1-AR and β-AR antagonists (prazosin and propranolol). All antagonists diminished the hemodynamic response induced by Adr. Losartan abolished hemodynamic response induced by AII, and AR antagonists had no effect when used alone. When combined, the antagonists caused a decrease in the hemodynamic response. The metabolic response induced by Adr was mainly mediated by ∝1-AR. A significant decrease in the hemodynamic response induced by Adr caused by losartan confirmed the participation of AT1-R. The metabolic response induced by AII was impaired by propranolol, indicating the participation of β-AR. When both ARs were blocked, the hemodynamic and metabolic responses were impaired in a cumulative effect. These results suggested that both ARs might be responsible for AII effects. This possible cross-talk between β-AR and AT1-R signaling in the hepatocytes has yet to be investigated and should be considered in the design of specific drugs.

Urinary cytokine profiles according to the site of blockade of the renin-angiotensin system in nephrectomized rats / Perfil de citocinas urinárias de acordo com o local de bloqueio do sistema renina angiotensina em ratos nefrectomizados

Abstract Introduction: It is still unknown how the pharmacological inhibition of the Renin Angiotensin System (RAS) impacts the levels of inflammation and fibrosis biomarkers. Objective: This study sought to evaluate the effect of enalapril, candesartan and aliskiren on urinary levels of cytokines in a model of chronic kidney disease (CKD). Methods: Male Wistar rats were submitted to surgical removal of ¾ of renal parenchyma to induce CKD (¾ nephrectomy), or subjected to sham surgery (control). Animals were then randomized into five groups: Sham surgery receiving vehicle; ¾ Nephrectomy receiving vehicle; ¾ Nephrectomy receiving enalapril (10 mg/kg); ¾ Nephrectomy receiving candesartan (10 mg/kg) and ¾ Nephrectomy receiving aliskiren (10 mg/kg). Urine output, water intake, mean arterial pressure (MAP) and urinary concentrations of creatinine, urea, albuminuria, Na+, K+, interleukin (IL) -1β, IL-6, IL-10 and transforming growth factor beta (TGF-β) were measured. Results: Nephrectomy significantly impaired renal function, increased MAP and altered the levels of all evaluated cytokines in urine. Enalapril, candesartan and aliskiren improved renal function and decreased MAP and IL-6 when compared to vehicle-treated nephrectomized group. Candesartan and aliskiren decreased IL-1β, while only candesartan reduced TGF-β and only aliskiren increased IL-10. Conclusion: Enalapril, candesartan and aliskiren presented similar effects on improving renal function and reducing MAP and urinary levels of IL-6 in rats with CKD. On the other hand, cytokine profile differed according to the treatment, suggesting that differential mechanisms were triggered in response to the site of RAS blockade.

Resumo Introdução: Ainda não se sabe como a inibição farmacológica do Sistema Renina Angiotensina (SRA) afeta os níveis de biomarcadores de inflamação e fibrose. Objetivo: Este estudo pretendeu avaliar o efeito de enalapril, candesartan e alisquireno sobre os níveis urinários de citocinas em um modelo de doença renal crônica (DRC). Métodos: Ratos Wistar machos foram submetidos à remoção cirúrgica de ¾ do parênquima renal para induzir DRC (nefrectomia), ou submetidos à cirurgia fictícia (controle). Animais foram então randomizados em cinco grupos: Cirurgia fictícia recebendo veículo; Nefrectomia recebendo veículo; Nefrectomia recebendo enalapril (10 mg/kg); Nefrectomia recebendo candesartan (10 mg/kg) e Nefrectomia recebendo alisquireno (10 mg/kg). Débito urinário, ingesta hídrica, pressão arterial media (PAM) e concentrações urinárias de creatinina, ureia, albumina, Na+, K+, interleucina (IL) -1β, IL-6, IL-10 e fator de transformação e crescimento beta (TGF-β) foram medidas. Resultados: A nefrectomia comprometeu significativamente a função renal, aumentou a PAM e alterou os níveis de todas as citocinas avaliadas na urina. Enalapril, candesartan e alisquireno melhoraram a função renal e diminuíram a PAM e a IL-6 quando comparado aos grupo de animais nefrectomizados tratados com veículo. Candesartan e alisquireno reduziram IL-1β, enquanto somente candesartan diminuiu o TGF-β e somente alisquireno aumentou a IL-10. Conclusão: Enalapril, candesartan e alisquireno apresentaram efeitos similares em relação à melhora da função renal e redução da PAM e dos níveis urinários de IL-6 em ratos com DRC. Por outro lado, o perfil de citocinas diferiu de acordo com o tratamento, sugerindo que diferentes mecanismos sejam desencadeados em resposta ao local de bloqueio do SRA.

Candesartan, rather than losartan, improves motor dysfunction in thioacetamide-induced chronic liver failure in rats

Minimal hepatic encephalopathy is more common than the acute syndrome. Losartan, the first angiotensin-II receptor blocker (ARB), and candesartan, another widely-used ARB, have protected against developing fibrogenesis, but there is no clear data about their curative antifibrotic effects. The current study was designed to examine their effects in an already-established model of hepatic fibrosis and also their effects on the associated motor dysfunction. Low-grade chronic liver failure (CLF) was induced in 3-month old Sprague-Dawley male rats using thioacetamide (TAA, 50 mg·kg−1·day−1) intraperitoneally for 2 weeks. The TAA-CLF rats were randomly divided into five groups (n=8) treated orally for 14 days (mg·kg−1·day−1) as follows: TAA (distilled water), losartan (5 and 10 mg/kg), and candesartan (0.1 and 0.3 mg/kg). Rats were tested for rotarod and open-field tests. Serum and hepatic biochemical markers, and hepatic histopathological changes were evaluated by H&E and Masson's staining. The TAA-CLF rats showed significant increases of hepatic malondialdehyde, hepatic expression of tumor necrosis factor-α (TNF-α), and serum ammonia, alanine aminotransferase, γ-glutamyl transferase, TNF-α, and malondialdehyde levels as well as significant decreases of hepatic and serum glutathione levels. All treatments significantly reversed these changes. The histopathological changes were moderate in losartan-5 and candesartan-0.1 groups and mild in losartan-10 and candesartan-0.3 groups. Only candesartan significantly improved TAA-induced motor dysfunction. In conclusion, therapeutic antifibrotic effects of losartan and candesartan in thioacetamide-induced hepatic fibrosis in rats are possibly through angiotensin-II receptor blocking, antioxidant, and anti-inflammatory activities. Improved motor dysfunction by candesartan could be attributed to better brain penetration and slower "off-rate" from angiotensin-II receptors. Clinical trials are recommended.

Influence of antihypertensive drugs on aortic and coronary effects of Ang-(1-7) in pressure-overloaded rats

This study investigated the influence of antihypertensive drugs, such as angiotensin-converting enzyme inhibitors (ACEIs), AT1 receptor blockers (ARBs), voltage-gated L-type calcium channel blockers, and mineralocorticoid receptor antagonists (MRAs), on the effects of angiotensin-(1-7) [Ang-(1-7)] on aorta and coronary arteries from pressure-overloaded rats. Pressure overload was induced by abdominal aortic banding (AB). To evaluate the role of antihypertensive drugs on the effect of Ang-(1-7), AB male Wistar rats weighing 250–300 g were treated with vehicle or low doses (5 mg·kg-1·day-1, gavage) of losartan, captopril, amlodipine, or spironolactone. Isolated aortic rings and isolated perfused hearts under constant flow were used to evaluate the effect of Ang-(1-7) in thoracic aorta and coronary arteries, respectively. Ang-(1-7) induced a significant relaxation in the aorta of sham animals, but this effect was reduced in the aortas of AB rats. Chronic treatments with losartan, captopril or amlodipine, but not with spironolactone, restored the Ang-(1-7)-induced aorta relaxation in AB rats. The coronary vasodilatation evoked by Ang-(1-7) in sham rats was blunted in hypertrophic rats. Only the treatment with losartan restored the coronary vasodilatory effect of Ang-(1-7) in AB rat hearts. These data support a beneficial vascular effect of an association of Ang-(1-7) and some antihypertensive drugs. Thus, this association may have potential as a new therapeutic strategy for cardiovascular diseases.

Avaliação dos eixos ECA / ANG II / AT1 e ECA-2 / ANG (1-7) / MAS em fibroblastos de gengiva e ligamento periodontal humanos estimulados por IL-1ß e sua contribuição na produção e regulação de citocinas e quimiocinas / Evaluation ACE /ANG II /AT1 and ACE-2 /ANG (1-7) /MAS axis in gingival and periodontal ligament human fibroblasts stimulated with IL-1ß and its contribution in the production of cytokines and chemokines

O Sistema renina-angiotensina (SRA) tem sido relatado como um importante modulador de processos inflamatórios e imunológicos, incluindo a doença periodontal (DP). Estudos sugerem neste sistema um eixo alternativo (ECA-2 /ANG(1-7) /MAS) que atuaria como um contra-regulador de efeitos mediados pelo clássico eixo (ECA /ANGII /AT1). Sabe-se que bactérias periodontopatogênicas, como a Porphyromonas gingivalis (Pg), possuem componentes bioativos de membrana (ex. lipopolissacarídeos-LPS) capazes de induzir uma forte resposta imune no hospedeiro devido à liberação de citocinas nas células, entre elas Interleucina (IL)- 1ß. Neste contexto, fibroblastos são as células mais abundantes nos tecidos periodontais e possuem em sua superfície celular receptores necessários para o reconhecimento da invasão bacteriana, ativando cascatas intracelulares, que levam à produção de citocinas. O objetivo deste estudo foi verificar se os eixos ECA/ ANGII/ AT1 e ECA-2/ ANG(1-7)/ MAS contribuem para a produção e/ ou regulação de citocinas inflamatórias (CI) por fibroblastos de gengiva humana (HGF) e ligamento periodontal humano (HPLF) estimulados por IL-1ß. Após o pré-tratamento com Losartan e Ang (1-7) ou silenciamento mediado por RNA de interferência (RNAi) de AT1, HGF e HPLF foram estimulados por IL-1ß por 3 horas (RNAm) ou 24 horas (proteína). Expressão de RNAm para AT1, MAS, ECA, ECA-2, IL-1ß, TNF-α, IL-6, IL-8, IL-10, TGF-ß, CXCL12, RANK-L e OPG foram avaliados por RT-qPCR e das proteínas IL-6, IL-8, ECA e ECA-2 por ELISA. Foi realizado também Western Blot para detecção de AT1 e ECA nos extratos celulares e dosagem de nitrito no sobrenadante das culturas. Ambos os subtipos de fibroblastos mostraram aumento da expressão de RNAm para AT1, IL-1ß, IL-6, IL-8, TNF-α e OPG, quando estimulados por IL-1ß. No entanto, apenas em HPLF foi observado aumento para MAS, ECA e TGF-ß. Losartan e Ang (1-7) não modularam o transcrito, a secreção de CI e nem a produção de nitrito no sobrenadante das culturas, tanto em HGF como em HPLF. O silenciamento do receptor AT1 reduziu a secreção de IL-6 e IL-8 induzida por IL-1ß em cultura de HGF e HPLF e aumentou a expressão gênica de OPG somente em HGF. Estes resultados sugerem que o silenciamento de AT1, mas não o bloqueio farmacológico deste receptor pelo antagonista Losartan, em HGF e HPLF, pode controlar a produção de IL-6 e IL-8, que por sua vez contribuem para a patogênese periodontal.(AU)

The renin-angiotensin system (RAS) has been reported as an important modulator of inflammatory and immune responses, including periodontal disease (PD). Studies suggest an alternative axis as part of this system (ACE-2 / ANG (1-7) / MAS) that would act as counter-regulatory to the classical axis (ECA / ANGII / AT1). It is known that periodontal bacteria such as Porphyromonas gingivalis (Pg) have bioactive components in their membrane (such as lipopolysaccharide-LPS) capable of inducing a strong immune response in the host due to the release of cytokines in cells, including interleukin (IL) - 1ß. In this regard, fibroblasts are the most abundant cells in periodontal tissues and receptors needed for the recognition of bacterial invasion by activating intracellular cascades that lead to cytokine production. The aim of this study was to determine whether the axes ACE / ANGII / AT1 and ACE-2 / ANG (1-7) / MAS contribute to the production and / or regulation of inflammatory cytokines (IC) by fibroblasts of human gingiva (HGF) and human periodontal ligament (HPLF) stimulated IL-1ß. After pre-treatment with Losartan, Ang (1-7) or silencing mediated by RNA interference (RNAi) of AT1, HGF and HPLF were stimulated by IL-1ß for 3 hours (RNAm) or 24 hours (protein). Expression mRNA for AT1, MAS, ACE, ACE-2, IL-1ß, TNF-α, IL-6, IL-8, IL-10, TGF-ß, CXCL12, RANK-L and OPG was assessed by RT- qPCR and proteins IL-6, IL-8, ACE and ACE-2 by ELISA. Western Blot for the detection of AT1 and ECA and dosage of nitrite was also performed. Experiments stimulated by IL-1ß showed a positive control for gene expression AT1, IL-1ß, IL-6, IL-8, TNF-α and OPG in HGF and HPLF and MAS, ACE and TGF-ß only HPLF. Losartan and Ang (1-7) did not modulate the transcription and secretion of IC and no nitrite production in the culture supernatant of HGF and HPLF. The silencing AT1 reduced IL-6 secretion and IL-8 induced by IL- ß in cultured HGF and HPLF and increased OPG gene expression only HGF. These results suggest that silencing AT1, but not pharmacological blockade of this receptor by Losartan in HPLF and HGF, can control the production of IL-6 and IL-8, which in turn contribute to the pathogenesis of periodontal disease.(AU)

Angiotensin II Modulates p130Cas of Podocytes by the Suppression of AMP-Activated Protein Kinase

Angiotensin II (Ang II) induces the pathological process of vascular structures, including renal glomeruli by hemodynamic and nonhemodynamic direct effects. In kidneys, Ang II plays an important role in the development of proteinuria by the modification of podocyte molecules. We have previously found that Ang II suppressed podocyte AMP-activated protein kinase (AMPK) via Ang II type 1 receptor and MAPK signaling pathway. In the present study, we investigated the roles of AMPK on the changes of p130Cas of podocyte by Ang II. We cultured mouse podocytes and treated them with various concentrations of Ang II and AMPK-modulating agents and analyzed the changes of p130Cas by confocal imaging and western blotting. In immunofluorescence study, Ang II decreased the intensity of p130Cas and changed its localization from peripheral cytoplasm into peri-nuclear areas in a concentrated pattern in podocytes. Ang II also reduced the amount of p130Cas in time and dose-sensitive manners. AMPK activators, metformin and AICAR, restored the suppressed and mal-localized p130Cas significantly, whereas, compound C, an AMPK inhibitor, further aggravated the changes of p130Cas. Losartan, an Ang II type 1 receptor antagonist, recovered the abnormal changes of p130Cas suppressed by Ang II. These results suggest that Ang II induces the relocalization and suppression of podocyte p130Cas by the suppression of AMPK via Ang II type 1 receptor, which would contribute to Ang II-induced podocyte injury.

Angiotensin III increases monocyte chemoattractant protein-1 expression in cultured human proximal tubular epithelial cells

BACKGROUND/AIMS: We investigated whether angiotensin III (Ang III) is involved in monocyte recruitment through regulation of the chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured human proximal tubular epithelial cells (HK-2 cells). METHODS: We measured MCP-1 levels in HK-2 cells that had been treated with various concentrations of Ang III and Ang II type-1 (AT1) receptor antagonists at various time points. The phosphorylation states of p38, c-Jun N-terminal kinases (JNK), and extracellular-signal-regulated kinases were measured in Ang III-treated cells to explore the mitogen-activated protein kinase (MAPK) pathway. MCP-1 levels in HK-2 cell-conditioned media were measured after pre-treatment with the transcription factor inhibitors curcumin or pyrrolidine dithiocarbamate. RESULTS: Ang III increased MCP-1 protein production in dose- and time-dependent manners in HK-2 cells, which was inhibited by the AT1 receptor blocker losartan. p38 MAPK activity increased significantly in HK-2 cells exposed to Ang III for 30 minutes, and was sustained at higher levels after 60 minutes (p < 0.05). Total phosphorylated JNK protein levels tended to increase 20 minutes after stimulation with Ang III. Pre-treatment with a p38 inhibitor, a JNK inhibitor, or curcumin significantly inhibited Ang III-induced MCP-1 production. CONCLUSIONS: Ang III increases MCP-1 synthesis via stimulation of intracellular p38 and JNK MAPK signaling activity and subsequent activated protein-1 transcriptional activity in HK-2 cells.

Olmesartan restores the protective effect of remote ischemic perconditioning against myocardial ischemia/reperfusion injury in spontaneously hypertensive rats

OBJECTIVES: Remote ischemic perconditioning is the newest technique used to lessen ischemia/reperfusion injury. However, its effect in hypertensive animals has not been investigated. This study aimed to examine the effect of remote ischemic perconditioning in spontaneously hypertensive rats and determine whether chronic treatment with Olmesartan could influence the effect of remote ischemic perconditioning. METHODS: Sixty rats were randomly divided into six groups: vehicle-sham, vehicle-ischemia/reperfusion injury, vehicle-remote ischemic perconditioning, olmesartan-sham, olmesartan-ischemia/reperfusion and olmesartan-remote ischemic perconditioning. The left ventricular mass index, creatine kinase concentration, infarct size, arrhythmia scores, HIF-1α mRNA expression, miR-21 expression and miR-210 expression were measured. RESULTS: Olmesartan significantly reduced the left ventricular mass index, decreased the creatine kinase concentration, limited the infarct size and reduced the arrhythmia score. The infarct size, creatine kinase concentration and arrhythmia score during reperfusion were similar for the vehicle-ischemia/reperfusion group and vehicle-remote ischemic perconditioning group. However, these values were significantly decreased in the olmesartan-remote ischemic perconditioning group compared to the olmesartan-ischemia/reperfusion injury group. HIF-1α, miR-21 and miR-210 expression were markedly down-regulated in the Olmesartan-sham group compared to the vehicle-sham group and significantly up-regulated in the olmesartan-remote ischemic perconditioning group compared to the olmesartan-ischemia/reperfusion injury group. CONCLUSION: The results indicate that (1) the protective effect of remote ischemic perconditioning is lost in vehicle-treated rats and that chronic treatment with Olmesartan restores the protective effect of remote ischemic perconditioning; (2) chronic treatment with Olmesartan down-regulates HIF-1α, ...

Bloqueio do receptor AT1 da Angiotensina II reduz o número de folículos antrais em ratas com obesidade induzida por dieta de cafeteria / Blockade of AT1 receptor of Angiotensin II reduces the number of antral follicles in female rats with obesity induced by cafeteria diet

OBJETIVO: Avaliar o desenvolvimento folicular em ratas Wistar com obesidade induzida por dieta de cafeteria (DCAF) submetidas à administração de losartan (LOS), um antagonista do receptor AT1 da Angiotensina II. MÉTODOS: Aos 21 dias de vida, as ratas foram separadas aleatoriamente em dois grupos: controle (CTL), que recebeu ração padrão, e cafeteria (CAF), que recebeu a DCAF, altamente palatável e calórica. Aos 70 dias de vida, início da idade reprodutiva, animais do grupo CAF foram subdivididos em dois grupos (n=15/grupo): CAF, que recebeu água, e CAF+LOS, que recebeu 30 mg/kg de peso corporal (PC) de LOS por gavagem durante 30 dias. O grupo CTL também recebeu água por gavagem. Aos 100 dias de vida foi realizada a eutanásia dos animais e o PC e das gorduras retroperitoneal, perigonadal e subcutânea foi avaliado. Os ovários direitos foram retirados para contagem do número dos diferentes tipos de folículos ovarianos. As concentrações plasmáticas dos hormônios folículo-estimulantes (FSH), luteinizante (LH), prolactina (PRL) e progesterona foram avaliadas. Os resultados foram expressos como média±erro padrão da média. Para análise estatística, foi utilizado one-way ANOVA, seguido pelo pós-teste de Newman-Keuls (p<0,05). RESULTADOS: O PC e das gorduras, assim como o número de folículos antrais, foi elevado no grupo CAF em relação ao CTL. Todavia, as concentrações de FSH e LH foram mais baixas entre os animais CAF. A administração de LOS reduziu o PC e das gorduras retroperitoneal e subcutânea, bem como o número de folículos antrais. O tratamento com LOS atenuou a redução das concentrações de FSH e de LH. As concentrações de progesterona e PRL foram semelhantes entre os grupos estudados. CONCLUSÃO: O uso de LOS pode favorecer o desenvolvimento folicular em fêmeas obesas e pode possibilitar sua utilização como fármaco coadjuvante no tratamento da infertilidade associada à obesidade. .

PURPOSE: To evaluate the follicular development of female Wistar rats with obesity induced by the cafeteria diet, submitted to the administration of losartan (LOS), an antagonist of the AT1 receptor of Angiotensin II. METHODS: At weaning (21 days of age), female Wistar rats were randomly divided, into two groups: control (CTL) that received standard chow and cafeteria (CAF) that received a cafeteria diet, a highly palatable and highly caloric diet. At 70 days of age, at the beginning of the reproductive age, animals of the CAF group were subdivided into two groups (n=15/group): CAF, that received water, and CAF+LOS, that received LOS for 30 days. The CTL group also received water by gavage. At 100 days of age, the animals were euthanized and body weight (BW) as well as the retroperitoneal, perigonadal and subcutaneous fat weights were analyzed. The right ovaries were isolated for counting the number of primary, secondary, antral and mature follicles. Plasma levels of FSH, LH, prolactin and progesterone hormones were analyzed. The results were expressed as mean±standard error of the mean. Data were analyzed statistically by one-way ANOVA followed by the Newman-Keuls post-test (p<0.05). RESULTS: BW and fat weight, as well as the number of antral follicles, were higher in the CAF group compared to the CTL group. However, FSH and LH levels were lower in CAF animals compared to CTL animals. LOS administration attenuated the reduction of FSH and LH levels. Progesterone and PRL levels were similar among groups. CONCLUSION: LOS could improve follicular development in obese females and could be used as an adjunctive drug in the treatment of infertility associated with obesity. .

Effect of candesartan on the expression of sclera-choroidal intercellular adhesion molecule-1 in hypercholesterolemic models

OBJECTIVE: To evaluate the effect of blocking the angiotensin II AT-1 receptor by the systemic administration of candesartan on the expression of intercellular adhesion molecule-1 in the sclera and choroid of hypercholesterolemic rabbits. METHODS: New Zealand rabbits were divided into 3 groups, as follows: GI, which was fed a rabbit standard diet; GII, which was fed a hypercholesterolemic diet; and GIII, which received hypercholesterolemic diet plus candesartan. Samples of the rabbits' sclera and choroid were then studied by hematoxylin-eosin staining and histomorphometric and immunohistochemical analyses for intercellular adhesion molecule-1 expression. RESULTS: Histological analysis of hematoxylin- and eosin-stained sclera and choroid revealed that macrophages were rarely present in GI, and GII had significantly increased macrophage numbers compared to GIII. Moreover, in GII, the sclera and choroid morphometry showed a significant increase in thickness in comparison to GI and GIII. GIII presented a significant increase in thickness in relation to GI. Sclera and choroid immunohistochemical analysis for intercellular adhesion molecule-1 expression revealed a significant increase in immunoreactivity in GII in relation to GI and GIII. GIII showed a significant increase in immunoreactivity in relation to GI. CONCLUSION: Candesartan reduced the expression of intercellular adhesion molecule-1 and consequently macrophage accumulation in the sclera and choroid of hypercholesterolemic rabbits. .

Additional antihypertensive effect of magnesium supplementation with an angiotensin II receptor blocker in hypomagnesemic rats

BACKGROUND/AIMS: Magnesium (Mg) is an essential element for vascular function and blood pressure regulation. Several studies have demonstrated that Mg concentration is inversely associated with blood pressure, and that Mg supplementation attenuates hypertension. The purpose of this study was to evaluate the effect of dietary Mg supplementation on the blood pressure effects of an angiotensin II receptor blocker (ARB) in hypomagnesemic rats. METHODS: Fifty male Sprague-Dawley rats were randomly divided into Mg-deficient (n = 30), normal diet plus Mg (n = 10), and control groups (n = 10). Mg-free, high-Mg, and normal-Mg diets were respectively fed to the rats. After 14 weeks, 10 of the 30 Mg-deficient rats were treated with Mg, 10 Mg-deficient rats received an ARB, and 10 Mg-deficient rats received an ARB plus Mg for 4 weeks. RESULTS: Systolic blood pressure was significantly higher in the Mg-deficient rats than in the control rats at week 14. Hypomagnesemic rats exhibited decreased systolic blood pressure after treatment with Mg, and systolic blood pressure showed a greater decrease after ARB treatment. Treatment with the ARB/Mg combination resulted in the greatest decrease in systolic blood pressure. Mg deficiency did not affect the serum angiotensin II level, but did increase the serum aldosterone concentration. Concomitant Mg/ARB supplementation significantly decreased the elevated serum aldosterone level in hypomagnesemic rats. Kidney tissues of the hypomagnesemic rats revealed mild to moderate inflammatory infiltrates. Mg and/or ARB treatment did not reverse the inflammatory reaction in the kidneys of hypomagnesemic rats. CONCLUSIONS: Concurrent dietary Mg supplementation can enhance ARB-induced blood pressure reduction in rats with hypomagnesemic hypertension.

Efecto de los antagonistas de los receptores AT1 de la angiotensina II sobre la enfermedad periodontal inducida por inyecciones de lipopolisacáridos en ratas / Effect of ang II AT1 receptor antagonists, on periodontal disease induced by injections of lipopolysaccharide in rats

La Enfermedad Periodontal (EP) es una condición inflamatoria progresiva que afecta los tejidos que soportan y rodean a los dientes. Las endotoxinas bacterianas como los lipopolisacáridos (LPS), inducen una cascada inflamatoria causando resorción ósea mediante la producción y modulación de la red de citoquinas del tejido periodontal, del sistema RANK-RANKL-OPG y de la producción de especies reactivas del oxígeno (ERO). Siendo la vía final la activación del factor de transcripción NFκB para el control de la infección. Se sabe que el Sistema Renina Angiotensina (SRA) esta involucrado en la inflamación. Estas acciones pro-inflamatorias de la Ang II son producidas por la activación de NFkB mediante los receptores AT1, y por la generación de ERO. Nuestro objetivo fue determinar si la inhibición del receptor AT1 con el uso del valsartán reduciría la respuesta inmunitaria innata inflamatoria en un modelo de EP inducida por las inyecciones de LPS en la encía de las ratas. Nuestros resultados demuestran que el Valsartán disminuyó la leucocitosis sistémica, la movilidad dentaria, atenuó la pérdida de peso corporal de las ratas, disminuyó la formación de enzimas antioxidantes y NOS, redujo la producción y liberación de citocinas pro inflamatorias y aumentó las citocinas antinflamatorias, disminuyó la activación de p-p38, p-NFkB y la expresión de los receptores TLR4. El Valsartán también revirtió los efectos del LPS sobre la resorción ósea ya que disminuyó el número de osteoclastos, la expresión de los receptores RANK/RANKL/OPG y la relación RANKL/OPG y aumentó los depósitos de calcio y colágeno. Los mecanismos por los cuales el Valsartán reduce los efectos inflamatorios producidos por el LPS no están claras, pero la interferencia del ensamblaje de la NAD(P)H oxidasa con apocinina y el Tempol, indica que el Valsartán puede interferir con los pasos para el reconocimiento de LPS y su asociación con TLR4. Concluyéndose que las ERO participan en la señalización intracelular de la ANG II, vía el AT1R. Este estudio ayuda a dilucidar el papel del SRA en procesos inflamatorios. Además contribuye con sus resultados a ofrecer una alternativa terapéutica en el tratamiento de la EP.

The effect of anti-hypertensive drugs on the obstructive pancreatitis in rats / Efeitos de fármacos anti-hipertensivos sobre pancreatite obstrutiva em ratos

PURPOSE: To investigate the effect of ACE inhibitor, lisinopril and AT1 blocker, losartan, on the obstructive pancreatitis in rat. METHODS: Acute pancreatitis in rats (n=21) was induced for a common hepatic duct were ligated proximal to its entry into the pancreas and the common bile - pancreatic duct were also ligated near its junction with the duodenum, under ether anesthesia, after which the abdomen were closed. The animals was divided in tree groups, being two treated and control group. The animals was treated with Losartan and Lisinopril at the dose of 10µg/Kg body weight per day, i.p., in a proportional volume, for five days, before and after treatement. RESULTS: The inflammation, collagen deposition in the pancreas of treated animals were smaller, suggesting that the use of antihypertensive agents interfered positively in the depletion of the injury of the pancreas. Scythe showed a correlation between activity of pancreatic stellate cells (PSCs) lower in treated animals when compared to control. CONCLUSION: The pancreatic stellate cells strength are involved in collagen production during acute pancreatitis and why antihypertensive drugs such as lisinopril and losartan may possibly have beneficial effects in reducing pancreatic fibrosis in models of experimental obstructive pancreatitis.

OBJETIVO: Investigar o efeito de um inibidor da ECA, lisinopril e bloqueador AT1, losartan, a pancreatite obstrutiva em ratos. MÉTODOS: Pancreatite aguda em ratos (n = 21) foi induzida por um ducto hepático comum foram ligados proximal à sua entrada no pâncreas e da bílis comum - ducto pancreático também foram ligados perto de sua junção com o duodeno, sob anestesia com éter, após o que abdome foram fechadas. Os animais foram divididos em três grupos, sendo dois tratados eo grupo controle. Os animais foram tratados com lisinopril e losartan na dose de 10µg/Kg de peso corporal por dia, IP, em um volume proporcional, por cinco dias, antes e depois do tratamento com. RESULTADOS: A inflamação, deposição de colágeno no pâncreas de animais tratados foram menores, sugerindo que o uso de agentes anti-hipertensivos interferiram positivamente na diminuição da lesão do pâncreas. Este estudo mostrou uma correlação entre a atividade das células pancreáticas estreladas (CSP) menor nos animais tratados quando comparados ao control. CONCLUSÃO: A força das células pancreáticas estreladas está envolvida na produção de colágeno durante a pancreatite aguda e por medicamentos anti-hipertensivos, tais como lisinopril e losartan pode eventualmente ter efeitos benéficos na redução da fibrose do pâncreas em modelos experimentais de pancreatite obstrutiva.

Anti-albuminuric efficacy of a combination of angiotensin converting enzyme inhibitor & angiotensin receptor blocker in type 1 DM with nephropathy.

Background & objective: The efficacy of the combination of angiotensin receptor blockers (ARBs) and angiotensin converting enzyme (ACE) inhibitors in patients of type 1 diabetes mellitus (DM) with nephropathy is debatable. The antialbuminuric efficacy of dual blockade in patients of type 1 DM with micro- or macroabuminuria were evaluated. Methods: In this open label observational study 30 patients (20 male 10 female) with type 1 DM were included who were initially treated with telmisartan 80 mg for eight weeks followed by addition of ramipril 10 mg for a further eight weeks. Albuminuria reduction was studied at the end of each phase. Results: Therapy with telmisartan for 8 wk resulted in a 39 per cent (P<0.01) reduction in albumin excretion rate (AER). Combination therapy with telmisartan and ramipril produced a further reduction in AER of 33.4 per cent (P<0.01), amounting to a total AER reduction of 59 per cent (P<0.001). Dual blockade was more effective in the group of macroalbuminuric as compared to microalbuminuric subjects (P<0.05). Telmisartan produced a significant reduction in SBP (P<0.05). The addition of ramipril produced a further reduction in BP, the total reduction being 10.3 in SBP and 7.2 mmHg in DBP (P<0.001 for both). There was an increase in mean serum potassium of 0.39 mmol/l (P<0.01) from baseline at the end of the study period and two patients had hyperkalemia > 5.5 mmol/l with dual blockade. Interpretation & conclusion: Dual blockade with ramipril enhanced the antialbuminuric efficacy of telmisartan and further reduced blood pressure. The effect of dual blockade was more pronounced in the macroalbuminuric subjects and it was well tolerated. However, careful monitoring of serum potassium is required.

Adição de Bloqueador do receptor de angiotensina II na insuficiência cardíaca descompensada / Adición de bloqueante del receptor de angiotensina II en la insuficiencia cardiaca descompensada / Angiotensin II receptor blocker add-on therapy for low cardiac output in decompensated heart failure

FUNDAMENTO: Durante a descompensação da insuficiência cardíaca, ocorre uma intensa ativação do sistema renina-angiotensina-aldosterona, entretanto, o uso de inibidor da enzima de conversão de angiotensina (IECA) não pode bloqueá-lo completamente. De outro modo, a adição de bloqueador do receptor de angiotensina II (BRA) pode ser útil quando ocorre a dependência de inotrópico. Avaliamos a eficiência da associação BRA-IECA para retirada da dobutamina na insuficiência cardíaca avançada e descompensada. OBJETIVO: Avaliar a eficácia da associação de bloqueador do receptor AT1 de angiotensina II ao inibidor de enzima de conversão, para a retirada da dobutamina em pacientes com dependência de suporte inotrópico decorrente da descompensação aguda da insuficiência cardíaca crônica. MÉTODOS: Em um estudo caso-controle (N = 24), selecionamos pacientes internados por descompensação da insuficiência cardíaca e com uso por mais de 15 dias de dobutamina, ou uma ou mais tentativas sem sucesso de retirada; dose otimizada de IECA; e FEVE < 0,45. Os pacientes então receberam adicionalmente BRA (n = 12) ou não (controle, n = 12). O desfecho foi o sucesso na retirada da dobutamina, avaliado pela regressão logística, com p < 0,05. RESULTADOS: A fração de ejeção foi de 0,25, e a idade de 53 anos, com dose de dobutamina de 10,7 μg/kg.min. O sucesso na retirada de dobutamina ocorreu em oito pacientes do grupo BRA (67,7 por cento), e em dois no grupo controle (16,7 por cento). A "odds ratio" foi de 10,0 (intervalo de confiança de 95 por cento:1,4 a 69,3; p = 0,02). A piora da função renal foi semelhante (grupo BRA: 42 por cento vs. grupo controle: 67 por cento, p = 0,129). CONCLUSÃO: Neste estudo piloto, a associação BRA-IECA foi relacionada ao sucesso na retirada da dobutamina, na insuficiência cardíaca avançada descompesada. A piora da função renal foi semelhante em ambos os grupos. Estudos adicionais são necessários para esclarecer o assunto.

BACKGROUND: During heart failure (HF) decompensation, an intense activation of the renin-angiotensin-aldosterone system occurs; however, the use of angiotensin-converting enzyme inhibitor (ACEI) cannot block it completely. Otherwise, the addition of angiotensin II receptor blocker (ARB) can be useful when the inotropic dependence occurs. We evaluated the efficacy of the ARB-ACEI association on dobutamine withdrawal in advanced decompensated HF. OBJECTIVE: To assess the efficacy of association angiotensin receptor blocker - angiotensin converting enzyme inhibitor to withdraw the intravenous inotropic support in decompensated severe heart failure. METHODS: In a case-control study (N = 24), we selected patients admitted at the hospital due to HF that had been using dobutamine for more than 15 days, with one or more unsuccessful drug withdrawal attempts; optimized dose of ACEI and ejection fraction (EF) < 0.45. Then, the patients additionally received ARB (n=12) or not (control, n=12). The outcome was the successful dobutamine withdrawal, evaluated by logistic regression, with a p < 0.05. RESULTS: The EF was 0.25 and the age was 53 years, with a dobutamine dose of 10.7 μg/kg.min. The successful drug withdrawal was observed in 8 patients from the ARB group (67.7 percent) and in 2 patients from the control group (16.7 percent). The odds ratio (OR) was 10.0 (95 percentCI: 1.4 to 69.3; p = 0.02). The worsening in renal function was similar (ARB group: 42 percent vs. control group: 67 percent; p=0.129). CONCLUSION: In this pilot study, the ARB-ACEI association was associated with successful dobutamine withdrawal in advanced decompensated heart failure. The worsening in renal function was similar in both groups. Further studies are necessary to clarify the issue.

FUNDAMENTO: Durante la descompensación de la insuficiencia cardiaca, ocurre una intensa activación del sistema renina-angiotensina-aldosterona, sin embargo, el empleo de inhibidor de la enzima de conversión de angiotensina (IECA) no puede bloquearlo completamente. De otro modo, la adición de bloqueante del receptor de angiotensina II (BRA) puede ser útil cuando ocurre la dependencia de inotrópico. Evaluamos la eficiencia de la asociación BRA-IECA para retirada de la dobutamina en la insuficiencia cardiaca avanzada y descompensada. OBJETIVO: Evaluar la eficacia de la asociación de bloqueante del receptor AT1 de angiotensina II al inhibidor de enzima de conversión, para la retirada de la dobutamina en pacientes con dependencia de soporte inotrópico que trascurre de la descompensación aguda de la insuficiencia cardiaca crónica. MÉTODOS: En un estudio caso-control (N = 24), seleccionamos a pacientes internados por descompensación de la insuficiencia cardiaca y con empleo por más de 15 días de dobutamina, o una o más intentos sin éxito de retirada; dosis optimizada de IECA; y FEVI < 0,45. Así que los pacientes recibieron adicionalmente BRA (n = 12) o no (control, n = 12). El desenlace fue el éxito en la retirada de la dobutamina, evaluado por la regresión logística, con p < 0,05. RESULTADOS: La fracción de eyección fue de 0,25, y la edad de 53 años, con dosis de dobutamina de 10,7 μg/kg.min. El éxito en la retirada de dobutamina ocurrió en ocho pacientes del grupo BRA (67,7 por ciento), y en dos en el grupo control (16,7 por ciento). La "odds ratio" fue de 10,0 (intervalo de confianza de 95 por ciento:1,4 a 69,3; p = 0,02). El empeoramiento de la función renal se halló similar (grupo BRA: 42 por ciento vs grupo control: 67 por ciento, p = 0,129). CONCLUSIÓN: En este estudio piloto, la asociación BRA-IECA se relacionó al éxito en la retirada de la dobutamina, en la insuficiencia cardiaca avanzada descompensada. El empeoramiento de la función ...

Endogenous angiotensin II modulates nNOS expression in renovascular hypertension

Nitric oxide (NO) influences renal blood flow mainly as a result of neuronal nitric oxide synthase (nNOS). Nevertheless, it is unclear how nNOS expression is modulated by endogenous angiotensin II, an inhibitor of NO function. We tested the hypothesis that the angiotensin II AT1 receptor and oxidative stress mediated by NADPH oxidase contribute to the modulation of renal nNOS expression in two-kidney, one-clip (2K1C) hypertensive rats. Experiments were performed on male Wistar rats (150 to 170 g body weight) divided into 2K1C (N = 19) and sham-operated (N = 19) groups. nNOS expression in kidneys of 2K1C hypertensive rats (N = 9) was compared by Western blotting to that of 2K1C rats treated with low doses of the AT1 antagonist losartan (10 mg·kg-1·day-1; N = 5) or the superoxide scavenger tempol (0.2 mmol·kg-1·day-1; N = 5), which still remain hypertensive. After 28 days, nNOS expression was significantly increased by 1.7-fold in the clipped kidneys of 2K1C rats and by 3-fold in the non-clipped kidneys of 2K1C rats compared with sham rats, but was normalized by losartan. With tempol treatment, nNOS expression increased 2-fold in the clipped kidneys and 1.4-fold in the non-clipped kidneys compared with sham rats. The changes in nNOS expression were not followed by changes in the enzyme activity, as measured indirectly by the cGMP method. In conclusion, AT1 receptors and oxidative stress seem to be primary stimuli for increased nNOS expression, but this up-regulation does not result in higher enzyme activity.