Biomechanical Effects of Angiotensin 1-7 in Diabetes Rats Femur / Efectos Biomecánicos de la Angiotensina 1-7 en el Fémur de Ratas Diabéticas

SUMMARY: It is known that diabetes mellitus has late complications, including microvascular and macrovascular diseases. Diabetes can affect bones through biochemical markers of bone structure, density, and turnover. This study aimed to biomechanically investigate the bone-protective effects of angiotensin 1-7 (Ang 1-7), one of the active peptides in the renin-angiotensin system, in rats with diabetes. Thirty male Wistar albino rats, three months old and weighing 250-300 g, were divided into four groups: diabetes, Ang 1- 7, diabetes plus Ang 1-7, and control. One month later, diabetes developed in rats; the rats were sacrificed, and their right femur was removed. Three-point bending biomechanical tests were performed on the femurs. The diabetic group had significantly higher bone fragility than the other groups (Pr >.05). Bone fragility was lower, and bone flexibility was higher in the Ang 1-7 groups (Pr>F value 0.05). As a result of our study, the effect of Ang 1-7 on the bones of rats with diabetes was investigated biomechanically. Ang 1-7 has a protective impact on the bones of rats with diabetes.

Se sabe que la diabetes mellitus tiene complicaciones tardías, incluyendo enfermedades microvasculares y macrovasculares. La diabetes puede afectar los huesos a través de los marcadores bioquímicos de la estructura, la densidad y el recambio óseo. Este estudio tuvo como objetivo investigar biomecánicamente los efectos protectores en los huesos de la angiotensina 1-7 (Ang 1-7), uno de los péptidos activos en el sistema renina-angiotensina, en ratas con diabetes. Treinta ratas albinas Wistar macho, de tres meses de edad y con un peso de 250-300 g, se dividieron en cuatro grupos: diabetes, Ang 1-7, diabetes más Ang 1-7 y control. Un mes después, se desarrolló diabetes en ratas; se sacrificaron los animales y se extrajo su fémur derecho. Se realizaron pruebas biomecánicas de flexión de tres puntos en los fémures. El grupo diabéticos tenía una fragilidad ósea significativamente mayor que los otros grupos (Pr > 0,05). La fragilidad ósea fue menor y la flexibilidad ósea fue mayor en los grupos Ang 1-7 (valor Pr>F 0,05). Como resultado de nuestro estudio, se determinó biomecánicamente el efecto de Ang 1-7 en los huesos de ratas con diabetes. Se concluye que Ang 1-7 tiene un impacto protector en los huesos de ratas diabéticas.

Buzhong Yiqitang Reduces CIH-induced Pulmonary Inflammatory Injury by ACE2-Ang（1-7）-Mas Axis / 中国实验方剂学杂志

ObjectiveTo investigate the intervention effect of Buzhong Yiqitang （BZYQT） on pulmonary inflammation in mice induced by chronic intermittent hypoxia （CIH） and preliminarily elucidate its mechanism. MethodForty healthy male C57BL/6 mice aged 6-8 weeks were randomly divided into the following groups： normoxia group， model group （exposed to CIH）， and low-， medium-， and high-dose BZYQT groups. The normoxia group was exposed to a normoxic environment， while the model group and the low-， medium-， and high-dose BZYQT groups were exposed to intermittent hypoxia. In the BZYQT groups， the BZYQT （8.1， 16.2， 32.4 g·kg-1·d-1） was administered orally 30 min before placing the mice in the hypoxic chamber， while the model group and the normoxia group received an equivalent volume of normal saline. After five weeks of modeling， pulmonary function of the mice was measured using an EMKA animal lung function analyzer， and lung tissue samples were collected after the pulmonary function tests. Hematoxylin-eosin （HE） staining was performed to observe the histopathological changes in the lung tissue of each group. Enzyme-linked immunosorbent assay （ELISA） was used to measure the levels of interleukin-6 （IL-6）， interleukin-8 （IL-8）， tumor necrosis factor-α （TNF-α） in the serum， as well as angiotensin Ⅱ （Ang Ⅱ） and angiotensin-（1-7） ［Ang（1-7）］ in lung tissue. Western blot and immunohistochemistry were used to detect the protein expression of IL-6， IL-8， TNF-α， angiotensin-converting enzyme 2 （ACE2）， and mitochondrial assembly receptor （Mas）. ResultCompared with the normoxia group， the model group showed significant abnormalities in lung function （P<0.05， P<0.01）， lung tissue changes， such as thickening of alveolar walls and inflammatory cell infiltration， increased levels of IL-6， IL-8， TNF-α in the serum and Ang Ⅱ in lung tissue （P<0.01）， decreased level of Ang（1-7） （P<0.01）， increased protein expression of IL-6， IL-8， and TNF-α， and decreased protein expression of ACE2 and Mas （P<0.05， P<0.01）. Compared with the model group， the BZYQT groups showed improvement in lung function （P<0.05， P<0.01）， and HE staining of lung tissue showed approximately normal alveolar wall thickness and reduced inflammatory cell infiltration. Immunohistochemistry and Western blot analysis showed a significant decrease in the expression of inflammatory-related proteins （P<0.05， P<0.01）， and a significant increase in ACE2 and Mas protein expression （P<0.05， P<0.01）. ConclusionBZYQT can improve lung injury in mice exposed to CIH by regulating the ACE2-Ang（1-7）-Mas axis to inhibit inflammatory responses.

Effect of Fushengong Prescreption on Regulation-antagonism Effect of ACE-AngⅡ-AT1R Axis and ACE2-Ang(1-7)-MASR Axis of Rats with Chronic Renal Failure / 中国实验方剂学杂志

Objective:To study the effect of Fushengong prescreption on the regulation-antagonism effect of angiotensin converting enzyme-angiotensin Ⅱ-angiotensin Ⅱ 1 receptor （ACE-AngⅡ-AT1R） axis and angiotensin converting enzyme 2-angiotensin （1-7）-Mas receptor［ACE2-Ang（1-7）-MASR］ axis of rats with chronic renal failure（CRF）， and to explore its mechanism of delaying the development of CRF. Method:The 65 male SD rats were randomly divided into normal group （<italic>n</italic>=10） and modeling group （<italic>n</italic>=55）. The normal group was routinely reared， while the modeling group were administered by gavage with 0.25 g·kg^-1d^-1adenine suspension for 28 days. After the model was successfully established， the survival model rats were randomly divided into model group， benazepril group（0.01 g·kg^-1·d^-1）and low，medium and high dose of Fushengong prescreption groups （4，8，16 g·kg^-1·d^-1）. The normal group and model group were administered the same volume of normal saline by gavage， lasted for 28 days. After the experiment， systolic blood pressure （SBP） and diastolic blood pressure （DBP） of caudal artery were measured， and 24-hour urine was collected to determine 24-hour urine protein （24 h U-pro）. The content of serum creatinine（SCr） and blood urea nitrogen （BUN） in the serum were measured， the histological morphology was observed by hematoxylin eosin（HE）staining， and the degree of renal interstitial fibrosis was observed by Masson staining. Enzyme linked immunosorbent assay （ELISA） was used to determine the contents of AngⅡ， Ang （1-7） and Cystatin C （CysC） in serum and renal homogenate. The protein level of ACE， ACE2， AT1R and MASR were detected by Western blot. The expression of ACE and ACE2 protein in renal tissues were detected by immunohistochemistry. Result:Compared with normal group， the expression levels of SCr， BUN and CysC in model group were significantly increased（<italic>P</italic><0.05）， the content of AngⅡ in serum and kidney tissues were significantly increased， the content of Ang （1-7） were significantly decreased（<italic>P</italic><0.05）， the expression of ACE and AT1R protein in renal tissues were significantly increased（<italic>P</italic><0.05）， and the expression of ACE2 and MASR protein were significantly decreased（<italic>P</italic><0.05）. Compared with model group and benazepril group， after the intervention with Fushengong prescreption， the serum SCr，BUN and CysC decreased（<italic>P</italic><0.05），the content of AngⅡ in serum and kidney tissues decreased significantly，Ang（1-7） increased significantly（<italic>P</italic><0.05）， the expression of ACE and AT1R protein in renal tissues decreased significantly（<italic>P</italic><0.05）， ACE2 and MASR protein increased significantly（<italic>P</italic><0.05）. The high-dose Fushengong prescreption has the best effect. The high， medium and low-dose effects of Fushengong prescreption were dose-dependent. Conclusion:Fushengong prescreption improved renal function and pathological change of kidney in adenine-induced rats with chronic renal failure. The mechanism may be related to the inhibition of ACE-AngⅡ-AT1R axis and promotion of ACE2-Ang（1-7）-MASR axis ，which leads to the delaying of the progression of chronic renal failure.

The protective arm of the renin -angiotensin system may counteract the intense inflammatory process in fetuses with posterior urethral valves / O braço protetor do sistema renina-angiotensina pode contrapor-se ao intenso processo inflamatório em fetos com válvula de uretra posterior

Abstract Objective: Posterior urethral valve is the most common lower urinary tract obstruction in male children. A high percentage of patients with posterior urethral valve evolve to end‐stage renal disease. Previous studies showed that cytokines, chemokines, and components of the renin-angiotensin system contribute to the renal damage in obstructive uropathies. The authors recently found that urine samples from fetuses with posterior urethral valve have increased levels of inflammatory molecules. The aim of this study was to measure renin-angiotensin system molecules and to investigate their correlation with previously detected inflammatory markers in the same urine samples of fetuses with posterior urethral valve. Methods: Urine samples from 24 fetuses with posterior urethral valve were collected and compared to those from 22 healthy male newborns at the same gestational age (controls). Renin-angiotensin system components levels were measured by enzyme‐linked immunosorbent assay. Results: Fetuses with posterior urethral valve presented increased urinary levels of angiotensin (Ang) I, Ang‐(1‐7) and angiotensin‐converting enzyme 2 in comparison with controls. ACE levels were significantly reduced and Ang II levels were similar in fetuses with posterior urethral valve in comparison with controls. Conclusions: Increased urinary levels of angiotensin‐converting enzyme 2 and of Ang‐(1‐7) in fetuses with posterior urethral valve could represent a regulatory response to the intense inflammatory process triggered by posterior urethral valve.

Resumo Objetivo: A válvula de uretra posterior é a obstrução do trato urinário inferior mais comum em crianças do sexo masculino. Uma alta porcentagem de pacientes com válvula de uretra posterior evolui para doença renal em estágio final. Estudos anteriores mostraram que citocinas, quimiocinas e componentes do sistema renina-angiotensina contribuem para o dano renal em uropatias obstrutivas. Recentemente, descobrimos que amostras de urina de fetos com válvula de uretra posterior tinham níveis aumentados de moléculas inflamatórias. O objetivo deste estudo foi medir as moléculas de renina-angiotensina e investigar sua correlação com marcadores inflamatórios previamente detectados nas mesmas amostras de urina de fetos com válvula de uretra posterior. Métodos: Amostras de urina de 24 fetos com válvula de uretra posterior foram coletadas e comparadas com amostras de urina de 22 recém-nascidos saudáveis de mesma idade gestacional (controles). Os níveis dos componentes de SRA foram medidos por ensaio de imunoabsorção enzimática. Resultados: Os fetos com válvula de uretra posterior apresentaram níveis urinários aumentados de angiotensina (Ang) I, Ang-(1-7) e enzima conversora de angiotensina 2 em comparação com os controles. Os níveis de enzima conversora de angiotensina eram significativamente menores e os níveis de Ang II eram semelhantes nos fetos com válvula de uretra posterior em comparação com os controles. Conclusões: O aumento dos níveis urinários de enzima conversora de angiotensina 2 e de Ang-(1-7) em fetos com válvula de uretra posterior poderia representar uma resposta regulatória ao intenso processo inflamatório desencadeado pela válvula de uretra posterior.

Angiotensin 1-7: A Second Window of Protection in Hypertensive Patients

The effects of the renin-angiotensin-aldosterone system on the human body are so diverse and our knowledge about them is ever growing. Angiotensin 1-7 has been proven to play protective roles in patients with cardiovascular disorders including but not limited to hypertension. As is the case with Africa, the prevalence of hypertension in Sudan is rising, and its complications could be delayed by pharmacologically manipulating the levels of renin-angiotensin system metabolites. The aim of this review is to compare the advantageous and deleterious effects of Angiotensin 2 in contrast to those of Angiotensin 1-7 and to assert the well-established protective effects of Angiotensin 1-7 (systemically and locally) in hypertensive patients

Regulation of angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axis provides a new target for the treatment of cardiac remodeling and heart failure / 中华危重病急救医学

Cardiac remodeling is a common pathological manifestation of various end-stage cardiovascular diseases, which leads to myocardial diastolic and systolic dysfunction, low ejection fraction which cannot meet the needs of systemic tissue and organ metabolism, and ultimate progress into heart failure. Excessive activation of the classical renin angiotensin system (RAS), which is the angiotensin-converting enzyme-angiotensinⅡ-type 1 angiotensinⅡ receptor axis (ACE2-AngⅡ-AT1R axis), plays a key role in the pathological process of cardiac remodeling and heart failure. Angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axis [ACE2-Ang (1-7)-Mas axis] is an endogenous negative regulatory pathway of classical RAS, which can reduce its harmful effects. ACE2 is a monocarboxypeptidase that can hydrolyse AngⅡ and produce Ang (1-7), which has cardio-protective effects. Ang (1-7), via endogenous receptor Mas, plays the role of vasodilating, anti-proliferation and anti-differentiation, anti-fibrosis, anti-thrombosis and reversing myocardial remodeling. In recent years, with increasingly growing studies on the ACE2-Ang (1-7)-Mas axis, there are more understanding about their metabolic characteristics and mechanism of action. This article describes the role of ACE2 and Ang (1-7) in cardiac remodeling and heart failure and the related mechanisms, and discusses the potential benefits by regulating ACE2 activity and Ang (1-7) levels in clinical and experimental studies, hopefully providing potential therapeutic strategies.

Blockade of Endogenous Angiotensin-(1-7) in Hypothalamic Paraventricular Nucleus Attenuates High Salt-Induced Sympathoexcitation and Hypertension / 神经科学通报·英文版

Angiotensin (Ang)-(1-7) is an important biologically-active peptide of the renin-angiotensin system. This study was designed to determine whether inhibition of Ang-(1-7) in the hypothalamic paraventricular nucleus (PVN) attenuates sympathetic activity and elevates blood pressure by modulating pro-inflammatory cytokines (PICs) and oxidative stress in the PVN in salt-induced hypertension. Rats were fed either a high-salt (8% NaCl) or a normal salt diet (0.3% NaCl) for 10 weeks, followed by bilateral microinjections of the Ang-(1-7) antagonist A-779 or vehicle into the PVN. We found that the mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and plasma norepinephrine (NE) were significantly increased in salt-induced hypertensive rats. The high-salt diet also resulted in higher levels of the PICs interleukin-6, interleukin-1beta, tumor necrosis factor alpha, and monocyte chemotactic protein-1, as well as higher gp91 expression and superoxide production in the PVN. Microinjection of A-779 (3 nmol/50 nL) into the bilateral PVN of hypertensive rats not only attenuated MAP, RSNA, and NE, but also decreased the PICs and oxidative stress in the PVN. These results suggest that the increased MAP and sympathetic activity in salt-induced hypertension can be suppressed by blockade of endogenous Ang-(1-7) in the PVN, through modulation of PICs and oxidative stress.

Regulation of angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axis provides a new target for the treatment of cardiac remodeling and heart failure / 中华危重病急救医学

Cardiac remodeling is a common pathological manifestation of various end-stage cardiovascular diseases, which leads to myocardial diastolic and systolic dysfunction, low ejection fraction which cannot meet the needs of systemic tissue and organ metabolism, and ultimate progress into heart failure. Excessive activation of the classical renin angiotensin system (RAS), which is the angiotensin-converting enzyme-angiotensinⅡ-type 1 angiotensinⅡreceptor axis (ACE2-AngⅡ-AT1R axis), plays a key role in the pathological process of cardiac remodeling and heart failure. Angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axis [ACE2-Ang (1-7)-Mas axis] is an endogenous negative regulatory pathway of classical RAS, which can reduce its harmful effects. ACE2 is a monocarboxypeptidase that can hydrolyse AngⅡ and produce Ang (1-7), which has cardio-protective effects. Ang (1-7), via endogenous receptor Mas, plays the role of vasodilating, anti-proliferation and anti-differentiation, anti-fibrosis, anti-thrombosis and reversing myocardial remodeling. In recent years, with increasingly growing studies on the ACE2-Ang (1-7)-Mas axis, there are more understanding about their metabolic characteristics and mechanism of action. This article describes the role of ACE2 and Ang (1-7) in cardiac remodeling and heart failure and the related mechanisms, and discusses the potential benefits by regulating ACE2 activity and Ang (1-7) levels in clinical and experimental studies, hopefully providing potential therapeutic strategies.

Angiotensin (1-7) participating in renal fibrosis by inhibiting intermediate conductance Ca2+-activated K+ channels protein expression / 解剖学报

Objective: To investigate the relationship between the protective effect of angiotensin (Ang) (1-7) and the protein expression of intermediate conductance Ca2+-activated K+ channels (KCa3. 1) in renal fibrosis. Methods: Totally 60 male mice were randomly divided into 5 groups: control group (WT); Ang II group: mice received Ang II [1.4 mg/(kg.d)] by hypodermic injection; Ang II blocker group (Losartan): mice received Ang II [1.4 mg/(kg.d)] and Losartan [40 mg/(kg.d)]by hypodermic injection; Ang (1-7) group; mice received Ang II [1.4 mg/(kg.d)] and Ang (1-7) [0. 14 mg/(kg.d)] by hypodermic injection; diminazene aceturate(DIZE) group: mice received Ang II [1.4 mg/(kg.d)] and DIZE [10 mg/(kg.d)] by hypodermic injection. After 4 weeks of continuous administration, the related indicators were detected. Masson staining was used to detect the collagen content, and Western blotting was used to detect the protein expression of collagen type I, collagen type DI and KCa3. 1 channel. Results: Collagen deposition in renal tissue increased significantly after 4 weeks of hypodermic injection of Ang II (n = 12,P<0.01) compared with the WT group, which suggested that the model of renal fibrosis was successfully reproduced. Ang II significantly increased the synthesis of collagen type I and DI (n=6,P<0.01) and increased the expression of Kca3. 1 channel protein (n=6,P< 0. 01) in renal tissues, while Ang (1-7) and ACE2 activator DIZE significantly inhibited those exchanges (n= 12 or 6,P< 0. 01). Conclusion: Ang (1-7) plays a protective role in the process of renal fibrosis, which may be related to the downregulation of KCa3. 1 channel protein expression in renal tissue.

Angiotensin 1-7 attenuates angiotensin Ⅱ-induced human glomerular en-dothelial cell injury via Mas receptor / 中国病理生理杂志

AIM:To investigate the effect of angiotensin 1-7(Ang1-7)on the human glomerular endothelial cells(HGECs)injury induced by angiotensin Ⅱ(Ang Ⅱ)and its possible mechanism.METHODS: Cultured HGECs were divided into 6 groups randomly: control group, Ang Ⅱ group, Ang1-7 group, Ang Ⅱ +Ang1-7 group, Ang Ⅱ +Ang1-7+A779(an inhibitor of Mas receptor)group and A779 group.The apoptotic rate and reactive oxygen species (ROS)of HGECs were analyzed by flow cytometry and photographed by fluorescence microscopy.The levels of lactate de-hydrogenase(LDH),nitric oxide(NO),endothelin-1(ET-1),interleukin-6(IL-6),tumor necrosis factor-α(TNF-α), transforming growth factor-β(TGF-β),monocyte chemoattractant protein-1(MCP-1)and intercellular adhesion molecule-1(ICAM-1)in the supernatant of cell cultures were measured.RESULTS:Compared with the control group,the apoptot-ic rate and the average fluorescence intensity of ROS were increased in the Ang Ⅱ group,IL-6,TNF-α,TGF-β,ICAM-1 and MCP-1 in cell supernatants were also increased in the Ang Ⅱ group(P<0.05).Compared with the Ang Ⅱ group,the apoptotic rate,ROS level, and the above inflammatory factors were decreased in Ang Ⅱ +Ang1-7 group(P<0.05). Compared with the Ang Ⅱ +Ang1-7 group,adding A779 increased the cell apoptotic rate,ROS production and the releases of the above inflammatory factors in cell supernatants(P<0.05).Compared with the Ang Ⅱ group,adding Ang1-7 inhibi-ted the LDH leakage, ET-1 secretion and promoted the release of NO in a dose-dependent manner(P<0.05).CON-CLUSION:Ang1-7 attenuates the HGECs injury induced by Ang Ⅱ by inhibiting the Mas receptor.

Angiotensin 1-7 antagonizes cerebral ischemia-reperfusion injuries in mice through the TLR4/NF-κB signaling pathway / 国际生物医学工程杂志

Objective To investigate the protective effect and mechanism of angiotensin-(1-7) on cerebral ischemia-reperfusion injury in rats.Methods A rat model of middle cerebral artery occlusion (MCAO) reperfusion was established by non-invasive arteriolar clamping of bilateral common carotid artery in SD rats.The sham operation group and the model group were given artificial cerebrospinal fluid,and the low,medium and high dose treatment groups were given Ang-(1-7),with a dose of 1 pmol/0.5 μl/h,100 pmol/0.5 μl/h and 10 nmol/0.5 μl/h,respectively.After 24 h of arterial occlusion and reperfusion,Garcia JH standard was used to evaluate the neurological function of rats.The water content of brain tissue was determined by gravimetric method.The volume of cerebral infarction was determined by TIC staining method.The expression of Toll-like receptors 4 (TLR4) and nuclear factor-κB (NF-κB)p65 protein in ischemic parietal cortex were determined by Western Blot.The content of serum intercellular cell adhesion molecule-1(ICAM-1) and tumor necrosis factor-α (TNF-α) were detected by ELISA.Results Compared with the model group,the low,medium and high Ang-(1-7) dose groups significantly improved the neurological function scores of MACO rats (all P＜0.05).Compared with the model group,the brain water content of the high-dose Ang-(1-7) treatment group was significantly decreased (P＜0.05).Compared with the model group,the cerebral infarction volume of the rats in the low,medium and high Ang-(1-7) dose groups was significantly reduced (all P＜0.05).Compared.with the model group,the expression of TLR4 and NF-κB p65 protein in the middle and high-dose Ang-(1-7) treatment group was decreased (all P＜0.05),and the levels of ICAM-1 and TNF-α in serum was decreased (all P＜0.05).Conclusions Ang-(1-7) has a protective effect on cerebral ischemia-reperfusion injury of MACO rats,and its mechanism may be related with the inhibition of TLR4/NF-κB pathway.

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.

Deformação miocárdica radial por meio do speckle tracking bidimensional em suínos com hipertensão pulmonar induzida e tratados com angiotensina-(1-7) / Evaluation of myocardial radial deformation by bidimensional speckle tracking in pigs with pulmonary hypertension treated with angiotensin- (1-7)

A hipertensão arterial pulmonar (HAP) é uma doença complexa, caracterizada por disfunção endotelial, que resulta em remodelamento vascular pulmonar e elevação da pressão arterial pulmonar, com consequente insuficiência cardíaca direita. O speckle tracking bidimensional (2D-STE) é uma das mais recentes ferramentas da ecocardiografia, o qual tem sido empregado para avaliação mais precoce da função ventricular e do efeito da HAP sobre a função dos ventrículos esquerdo e direito. O objetivo deste estudo foi avaliar a deformação (St e StR) miocárdica radial do VE em modelo experimental de suínos com HAP induzida e tratados com angiotensina-(1-7), a fim de verificar as possibilidades desse novo fármaco nas respostas clínica e hemodinâmica, pois apresenta efeitos anti-inflamatório e vasodilatador, bem como ações antiproliferativas no sistema cardiovascular. Neste estudo, foi possível observar que os animais tratados com Ang-(1-7) apresentaram St e StR radiais maiores que o grupo placebo aos 60 dias de experimento, demonstrando uma melhora na função sistólica do miocárdio pelo aumento da deformação miocárdica (16,06±7,50 - placebo; 25,14±14,91 - Ang-(1-7)) e StR (1,28±0,51 - placebo; 1,51±0,58 - Ang-(1-7)). Essa melhora na função sistólica pode ser atribuída aos efeitos do fármaco, que reduziram também o desenvolvimento da hipertensão pulmonar. Diante dos resultados, acredita-se que a Ang-(1-7) possa ser um medicamento promissor para tratamento da HAP.(AU)

Pulmonary arterial hypertension (PAH) is a complex disease characterized by endothelial dysfunction resulting in pulmonary vascular remodeling, increased pulmonary arterial pressure, with subsequent right heart failure. The two-dimensional speckle tracking (2D-STE) is one of the newer tools used for early assessment of ventricular function. The aim of this study was to evaluate the radial myocardial deformation (St and StR) of LV in experimental pigs with induced PAH and treated with Ang- (1-7), checking the possibilities of this new drug in clinical and hemodynamic response, since it has anti-inflammatory effects and antiproliferative actions on the cardiovascular system. In this study we observed that animals treated with Ang (1-7) had radial St and StR higher than the placebo group at 60 days of the experiment demonstrating an improvement in systolic function of the myocardium by increased myocardial deformation (16.06±7.50 - placebo; 25.14±14.91 - Ang (1-7)) and StR (1.28±0.51 - placebo; 1.51±0.58 - Ang (1-7)). This improvement in systolic function can be attributed to drug effects while also reducing the development of pulmonary hypertension. Based on the results it is believed that Ang (1-7) may be a promising drug for the treatment of PAH.(AU)

Effects of perindopril at different doses on cardiac function and ACE2/Ang-(1-9)/Ang-(1-7) axis of ischemic cardiac dysfunction rabbits / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the different dose of perindopril on cardiac function in the rabbits with ische-mic cardiac dysfunction .METHODS:Male rabbits weighing 2.5~3.0 kg ( n=30) were randomly divided into 3 groups (n=10):high dose perindopril group (HD group), low dose perindopril group (LD group) and cardiac dysfunction group (CD group).The Left anterior descending coronary artery of the rabbits was ligatured for model preparation .In HD group, the rabbits were treated with perindopril split normal saline solution (1 g/L)2 mL· kg-1 · d-1 .In LD group, the rabbits were treated with perindopril split normal saline solution (0.33 g/L)2 mL· kg -1 · d-1.In CD group, the rabbits were treated with normal saline solution 2 mL· kg-1 · d-1 .Four weeks after treatment , the cardiac function was measured via echocardiography , the mRNA expression of angiotensin-converting enzyme 2 ( ACE2 ) and angiotensin type 2 receptor (AT2R) was analyzed by real-time PCR, serum angiotensin (Ang)-(1-9) and Ang-(1-7) levels were detected by ELISA. RESULTS:Compared with CD group , the cardiac function of the 2 groups treated with perindopril was significantly im-proved (P<0.01), and more improvement in HD group was observed than LD group (P<0.05).The serum angiotensin ( Ang)-(1-9) and Ang-(1-7) level and the mRNA expression of ACE 2 and AT2R in the 2 groups treated with perindopril were significantly improved (P<0.01).Compared with LD group, the mRNA expression of ACE2 and AT2R and the ser-um levels of Ang-(1-9) in HD group were significant improved (P<0.05), while no difference of serum Ang-(1-7) level was observed.Correlation analysis revealed that the improvement of the cardiac function was associated with serum Ang -(1-9) level, mRNA expression of ACE2 and AT2R (P<0.01), but has no significant correlation with serum Ang-(1-7) lev-el.CONCLUSION:High dose of perindopril may improve more cardiac function in ischemic cardiac dysfunction model in rabbits.The mechanism may relate to increasing serum Ang-(1-7) level to activate AT2R.

Angiotensin-(1-7) protects H9c2 cardiac cells against high glucose-in- duced injury and inflammation by inhibiting the interaction between TLR4 activation and necroptosis / 中国病理生理杂志

AIM:To investigate whether angiotensin-(1-7) [Ang-(1-7)] protects H9c2 cardiac cells against high glucose (HG)-induced injury and inflammation by inhibiting the interaction between Toll-like receptor 4 (TLR4) acti-vation and necroptosis .METHODS:The expression levels of receptor-interacting protein 3 ( RIP3;an indicator of necrop-tosis) and TLR4 were determined by Western blot .Cell viability was measured by CCK-8 assay.The activity of lactate de-hydrogenase ( LDH) in the culture medium was measured with a commercial kit .The releases of interleukin-1β( IL-1β) and tumor necrosis factor-α( TNF-α) were measured by ELISA .The intracellular level of reactive oxygen species ( ROS) was analyzed by 2 ’ , 7 ’-dichlorfluorescein-diacetate ( DCFH-DA ) stating followed by photofluorography .Mitochondrial membrane potential ( MMP) was examined by rhodamine 123 staining followed by photofluorography .RESULTS:After the H9c2 cardiac cells were treated with HG (35 mmol/L glucose) for 24 h, the expression of RIP3 was obviously increased . Co-treatment of the cells with 30μmol/L TAK-242 (an inhibitor of TLR4) attenuated the up-regulation of RIP3 induced by HG.Furthermore, the expression of TLR4 was significantly increased after the cells were exposed to HG for 24 h, and co-treatment of the cells with 100μmol/L necrostatin-1 ( Nec-1;a specific inhibitor of necroptosis ) and HG for 24 h attenua-ted the up-regulation of TLR4 expression induced by HG .Moreover, 1μmol/L Ang-(1-7) simultaneously blocked the up-regulation of the RIP3 and TLR4 induced by HG.On the other hand, co-treatment of the cells with 1μmol/L Ang-(1-7), 30 μmol/L TAK-242 or 100 μmol/L Nec-1 and HG for 24 h attenuated HG-induced injuries and inflammatory response , leading to the increase in the cell viability , and the decreases in the activity of LDH , ROS generation , MMP loss as well as the releases of IL-1βand TNF-α.CONCLUSION:Ang-(1-7) protects H9c2 cardiac cells against HG-induced injury and inflammation by inhibiting the interaction between TLR 4 activation and necroptosis .

Activation of endogenous angiotensin converting enzyme 2 prevents early injuries induced by hyperglycemia in rat retina

Diabetic retinopathy (DR) is a serious complication of diabetes mellitus that may result in blindness. We evaluated the effects of activation of endogenous angiotensin converting enzyme (ACE) 2 on the early stages of DR. Rats were administered an intravenous injection of streptozotocin to induce hyperglycemia. The ACE2 activator 1-[[2-(dimethylamino) ethyl] amino]-4-(hydroxymethyl)-7-[[(4-methylphenyl) sulfonyl] oxy]-9H-xanthone 9 (XNT) was administered by daily gavage. The death of retinal ganglion cells (RGC) was evaluated in histological sections, and retinal ACE2, caspase-3, and vascular endothelial growth factor (VEGF) expressions were analyzed by immunohistochemistry. XNT treatment increased ACE2 expression in retinas of hyperglycemic (HG) rats (control: 13.81±2.71 area%; HG: 14.29±4.30 area%; HG+XNT: 26.87±1.86 area%; P<0.05). Importantly, ACE2 activation significantly increased the RCG number in comparison with HG animals (control: 553.5±14.29; HG: 530.8±10.3 cells; HG+XNT: 575.3±16.5 cells; P<0.05). This effect was accompanied by a reduction in the expression of caspase-3 in RGC of the HG+XNT group when compared with untreated HG rats (control: 18.74±1.59; HG: 38.39±3.39 area%; HG+XNT: 27.83±2.80 area%; P<0.05). Treatment with XNT did not alter the VEGF expression in HG animals (P>0.05). Altogether, these findings indicate that activation of ACE2 reduced the death of retinal ganglion cells by apoptosis in HG rats.

Angiotensin-(1-7)/Mas receptor axis protects cardiomyocytes against high glucose-induced injury by modulating nuclear factor-κB pathway / 中国病理生理杂志

AIM:Tostudywhe ther theangiotens in-(1-7)[Ang-(1-7)]/Mas receptor axis protects cardio-myocytes against high glucose (HG)-induced injury by inhibiting nuclear factor-κB (NF-κB) pathway.METHODS:The cell viability was measured by CCK-8 assay.The intracellular levels of reactive oxygen species ( ROS) were detected by DCFH-DA staining .The number of apoptotic cells was tested by Hoechst 33258 nuclear staining .Mitochondrial membrane potential ( MMP) was examined by JC-1 staining.The levels of NF-κB p65 subunit and cleaved caspase-3 protein were de-termined by Western blotting.RESULTS: Treatment of H9c2 cardiac cells with 35 mmol/L glucose (HG) for 30, 60, 90, 120 and 150 min significantly enhanced the levels of phosphorated ( p) NF-κB p65, peaking at 60 min.Co-treatment of the cells with 1 μmol/L Ang-(1-7) and HG for 60 min attenuated the up-regulation of p-NF-κB p65 induced by HG. Co-treatment of the cells with Ang-(1-7) at concentrations of 0.1~30μmol/L and HG for 24 h inhibited HG-induced cy-totoxicity, evidenced by an increase in cell viability .On the other hand, 1 μmol/L Ang-(1-7) ameliorated HG-induced apoptosis, oxidative stress and mitochondrial damage , indicated by decreases in the number of apoptotic cells , cleaved caspase-3 level, ROS generation and MMP loss .However, the above cardioprotective effects of Ang-(1-7) were markedly blocked by A-779, an antagonist of Ang-(1-7) receptor (Mas receptor).Similarly, co-treatment of H9c2 cardiac cells with 100 μmol/L PDTC ( an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries induced by HG.CONCLUSION:Ang-(1-7)/Mas receptor axis prevents the cardiomyocytes from the HG-induced injury by inhibiting NF-κB pathway .

Angiotensin-(1-7)and tumors / 国际肿瘤学杂志

Angiotensin-(1-7)[Ang-(1-7)]is an endogenous peptide-hormone of the renin-angioten-sin system. Ang-(1-7),angiotensin-converting enzyme 2( ACE2)and MAS receptor constitute ACE2-Ang-(1-7)-Mas axis,which antagonizes the ACE-AngⅡ-AngⅡ type 1 receptor axis. Recent studies indicate that Ang-(1-7)has certain effects on treating tumors,including inhibition of angiogenesis,anti-cell proliferation and inhibition of tumor fibrosis. Researches on the roles and mechanisms of Ang-(1-7)can provide new target for treatment and prevention of cancer.

Angiotensin 1-7 attenuates left ventricular remodeling in deoxycorticosterone acetate salt hypertensive rats / 中国药理学通报

Aim To investigate the effect of angioten-sin 1-7 (Ang 1-7 )on the cardiac hypertrophy and my-ocardial fibrosis in deoxycorticosterone acetate (DOCA)-salt hypertensive rats and its possible mecha-nism.Methods Male Sprague-Dawley rats were used to establish DOCA-salt hypertensive model,which un-derwent uninephrectomy surgery and were subcutane-ously injected with a DOCA,and replaced drinking water with 1% saline solution for 4 weeks.DOCA-salt animals were implanted with osmotic minipumps, which delivered Ang 1-7 chronically for 4 weeks (200 ng ·kg-1 ·min-1 ).Arterial blood pressure,left ven-tricular function in rats,the area of myocardial cells in HE stained specimens,and the area of myocardial fi-brosis Sirius red staining specimens were measured. Real time PCR was used to detect the expression of at-rial natriuretic factor (ANF ) and β-myosin heavy chain (β-MHC)mRNA in heart,and TGF-β1 protein expression was observed by Western blot in myocardial tissue.Results In the first week,DOCA salt rat had a significant increase in arterial blood pressure,and reached a peak in the fourth week;while the left ven-tricular end-systolic pressure (LVESP),left ventricu-lar end-diastolic pressure (LVEDP ) and ventricular contraction the maximum rate of pressure rise (+dp/dt)had also undergone significant changes in DOCA salt rats. After chronic infusion of Ang 1-7 for 4 weeks,the arterial pressure,LVESP and LVEDP were significantly reduced and +dp/dt were increased sig-nificantly in DOCA salt rats (P<0.05 ,n=7 ).Ang 1-7 significantly reduced the cardiac index and myocar-dial cell area,as well as the up-regulated expression of ANF and β-MHC mRNA in DOCA salt rats (P <0.05 ,n =7 ).Meanwhile,Ang 1-7 also significantly decreased the perivascular fibrosis and interstitial fibro-sis area, and significantly inhibited the increase of TGF-β1 expression in DOCA salt rats (P<0.05 ,n=7 ).Conclusion These results indicate that Ang 1-7 has a cardioprotective effects through reducing arterial pressure and improving cardiac fibrosis and hypertro-phy in the DOCA-salt model of hypertension.

The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms

OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously) with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium) or a vasopressin V1 receptor antagonist [d(CH2)5 -Tyr(Me)-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7) (16 ± 2 mmHg, n = 12), which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7) at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7) at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7) triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism.