alamandine and Disease-Models--Animal

Stroke, a leading cause of mortality and disability, characterized by neuronal death, can be induced by a reduction or interruption of blood flow. In this study, the role of Alamandine, a new peptide of the renin-angiotensin system, was evaluated in in-vitro and in-vivo brain ischemia models.. In the in-vitro model, hippocampal slices from male C57/Bl6 mice were placed in a glucose-free aCSF solution and bubbled with 95% N2 and 5% CO2 to mimic brain ischemia. An Alamandine concentration-response curve was generated to evaluate cell damage, glutamatergic excitotoxicity, and cell death. In the in-vivo model, cerebral ischemia/ reperfusion was induced by bilateral occlusion of common carotid arteries (BCCAo-untreated) in SD rats. An intracerebroventricular injection of Alamandine was given 20-30 min before BCCAo. Animals were subjected to neurological tests 24 h and 72 h after BCCAo. Cytokine levels, oxidative stress markers, and immunofluorescence were assessed in the brain 72 h after BCCAo.. Alamandine was able to protect brain slices from cellular damage, excitotoxicity and cell death. When the Alamandine receptor was blocked, protective effects were lost. ICV injection of Alamandine attenuated neurological deficits of animals subjected to BCCAo and reduced the number of apoptotic neurons/cells. Furthermore, Alamandine induced anti-inflammatory effects in BCCAo animals as shown by reductions in TNFα, IL- 1β, IL-6, and antioxidant effects through attenuation of the decreased SOD, catalase, and GSH activities in the brain.. This study showed, for the first time, a neuroprotective role for Alamandine in different ischemic stroke models.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Humans; Ischemic Stroke; Male; Mice; Neuroprotection; Neuroprotective Agents; Oligopeptides; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stroke

Alamandine is the newest identified peptide of the renin-angiotensin system (RAS) and has protective effects in the cardiovascular system. Although the involvement of classical RAS components in the genesis and progression of cardiac remodeling is well known, less is known about the effects of alamandine. Therefore, in the present study we investigated the effects of alamandine on cardiac remodeling induced by transverse aortic constriction (TAC) in mice. Male mice (C57BL/6), 10-12 wk of age, were divided into three groups: sham operated, TAC, and TAC + ALA (30 µg/kg/day alamandine for 14 days). The TAC surgery was performed under ketamine and xylazine anesthesia. At the end of treatment, the animals were submitted to echocardiographic examination and subsequently euthanized for tissue collection. TAC induced myocyte hypertrophy, collagen deposition, and the expression of matrix metalloproteinase (MMP)-2 and transforming growth factor (TGF)-β in the left ventricle. These markers of cardiac remodeling were reduced by oral treatment with alamandine. Western blotting analysis showed that alamandine prevents the increase in ERK1/2 phosphorylation and reverts the decrease in 5'-adenosine monophosphate-activated protein kinase (AMPK)α phosphorylation induced by TAC. Although both TAC and TAC + ALA increased SERCA2 expression, the phosphorylation of phospholamban in the Thr17 residue was increased solely in the alamandine-treated group. The echocardiographic data showed that there are no functional or morphological alterations after 2 wk of TAC. Alamandine treatment prevents myocyte hypertrophy and cardiac fibrosis induced by TAC. Our results reinforce the cardioprotective role of alamandine and highlight its therapeutic potential for treating heart diseases related to pressure overload conditions.

Topics: AMP-Activated Protein Kinases; Animals; Aorta; Calcium-Binding Proteins; Cardiovascular Agents; Collagen; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Heart Ventricles; Hypertrophy, Left Ventricular; Ligation; Male; Matrix Metalloproteinase 2; Mice, Inbred C57BL; Oligopeptides; Oxidative Stress; Phosphorylation; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Signal Transduction; Transforming Growth Factor beta; Ventricular Function, Left; Ventricular Remodeling

This study was to determine whether alamandine (Ala) could reduce ischaemia and reperfusion (I/R) injury of kidney in rats.. Renal I/R was induced by an occlusion of bilateral renal arteries for 70 min and a 24-h reperfusion in vivo, and rat kidney proximal tubular epithelial cells NRK52E were exposed to 24 h of hypoxia and followed by 3-h reoxygenation (H/R) in vitro.. The elevated serum creatinine (Cr), blood cystatin C (CysC) and blood urea nitrogen (BUN) levels in I/R rats were inhibited by Ala treatment. Tumour necrosis factor alpha (TNF)-α, IL-1β, IL-6, cleaved caspase-3, cleaved caspase-8 and Bax were increased, and Bcl2 was reduced in the kidney of I/R rats, which were reversed by Ala administration. Ala reversed the increase of TNF-α, IL-1β, IL-6, cleaved caspase-3, cleaved caspase-8 and Bax and the decrease of Bcl2 in the H/R NRK52E cells. Ala could also inhibit the increase of oxidative stress levels in the kidney of I/R rats. NADPH oxidase 1 (Nox1) overexpression reversed the improving effects of Ala on renal function, inflammation and apoptosis of I/R rats.. These results indicated that Ala could improve renal function, attenuate inflammation and apoptosis in the kidney of I/R rats via inhibiting oxidative stress.

Topics: Acute Kidney Injury; Animals; Anti-Inflammatory Agents; Antioxidants; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 8; Cell Line; Disease Models, Animal; Inflammation; Interleukin-1beta; Interleukin-6; Ischemia; Kidney; Kidney Tubules, Proximal; Male; NADPH Oxidase 1; Oligopeptides; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Rats, Sprague-Dawley; Reperfusion Injury; Tumor Necrosis Factor-alpha

Topics: Angiotensin II; Animals; Antihypertensive Agents; Aorta, Thoracic; Arterial Pressure; Cells, Cultured; Disease Models, Animal; Fibrosis; Hypertension; Male; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nerve Tissue Proteins; Oligopeptides; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Signal Transduction; Vascular Remodeling

Alamandine is a new member of the angiotensin family. Here, we studied the mRNA and protein expression of cardiac angiotensin-converting enzyme 2 (ACE2) in the chronic phase of a rat model of 2-kidney, 1-clip hypertension (2K1C), and the effects of 2-week alamandine infusion on blood pressure, cardiac indices, and ACE2 mRNA and protein expression in the hearts. The rats were subjected to to sham-operation or placement of plexiglass clips around the left renal artery. Alamandine, at a dose of 600 µg/kg/d, was administered for 2 weeks via an osmotic mini-pump. At 18 weeks, after induction of hypertension, blood pressure and cardiac indices of contractility were measured using a Powerlab Physiograph system. The ACE2 mRNA and protein levels were determined using real time-PCR and Western blotting, respectively. In the hypertensive rats, alamandine caused a significant decrease in systolic blood pressure (p < 0.001), diastolic blood pressure (p < 0.001), left ventricular end-diastolic pressure (p < 0.001) and, left ventricular systolic pressure (p < 0.001) and increase in the maximum rate of pressure change in the left ventricle (dP/dt(max)) (p < 0.05). Also, the ACE2 mRNA expression in the heart increased in the hypertensive rats compared to the normotensive rats (p < 0.05), and alamandine restored this to normal values, although these changes were only seen at the mRNA and not the protein level. Histological analysis of cardiac tissue confirmed that alamandine decreased cardiac fibrosis and hypertrophy in 2K1C hypertensive rats. Our results indicate that alamandine, which acts as a depressor arm of the renin-angiotensin system, could be developed for treating hypertension.

Topics: Angiotensin-Converting Enzyme 2; Angiotensins; Animals; Antihypertensive Agents; Blood Pressure; Cardiovascular System; Disease Models, Animal; Hypertension, Renovascular; Hypertrophy; Kidney; Male; Myocardium; Oligopeptides; Peptidyl-Dipeptidase A; Random Allocation; Rats; Rats, Sprague-Dawley; RNA, Messenger

The aim of this study was to investigate whether alamandine plays a protective role in myocardial ischemia-reperfusion injury (IRI) by activating C-Jun N-terminal kinase (JNK) and inhibiting the expression of key proteins in nuclear factor-kappa B (NF-κB) pathway.. Twenty-four Sprague Dawley (SD) rats were numbered and divided into three groups using a random number table, including sham operation group (Sham group), myocardial ischemia-reperfusion injury model group (IRI group), and alamandine pretreatment and myocardial IRI treatment (alamandine group), with 8 SD rats per group. Myocardial tissues were collected from each group. The damage of myocardial tissue was detected using hematoxylin-eosin (H&E) and Masson staining. Finally, the expression levels of JNK and NF-κB pathway-related proteins in myocardial tissue of each group were detected by Western blot.. Compared with the IRI group, the alamandine treatment significantly improved cardiac function indicators induced by myocardial IRI in rats, including HR, MAP, LVESP, LVEDP, LVdp/dtmax, and -LVdp/dtmax. In addition, the pathological changes and cell damage of myocardium after alamandine pretreatment were significantly alleviated. At the same time, alamandine can significantly reduce the levels of TNF-α, IL-1β, IL-6, and NO. Finally, Western blot analysis showed that alamandine pre-treatment can protect cardiomyocytes from myocardial IRI by activating JNK phosphorylation and inhibiting the expression of related proteins in the NF-κB signaling pathway.. Alamandine can protect rat from myocardial IRI via activating JNK phosphorylation and inhibiting NF-κB signaling pathway to reduce the inflammatory response.

Topics: Animals; Cardiotonic Agents; Disease Models, Animal; Heart; Humans; Male; MAP Kinase Signaling System; Myocardial Reperfusion Injury; Myocardium; NF-kappa B; Oligopeptides; Phosphorylation; Rats; Rats, Sprague-Dawley

Alamandine is a newly discovered component of the renin-angiotensin system, which regulates blood pressure. In this study, the effect of alamandine on cardiovascular parameters in two-kidney, one clip (2K1C) hypertensive rats and normotensive rats, and the possible roles of the angiotensin II type 1 receptor (AT1R) and the PD123319-sensitive receptors in mediating this effect was investigated.Methods and Results:The cardiovascular parameters were monitored for 10 min before the infusion of the drugs or saline, and for 30 min afterward. In the 2K1C hypertensive rats, alamandine caused brief increases in mean arterial pressure (MAP), left-ventricular systolic pressure (LVSP) and maximum rate of pressure change in the left ventricle (dP/dt(max)). This was followed by decreases in these parameters, which extended throughout the remainder of the infusion period. Losartan, an AT1R blocker, abolished alamandine's initial pressor effect and PD123319, which can block AT2R and Mas-related G protein-coupled receptor D (MrgD) receptors, partially decreased the late depressor effect. Left ventricular end-diastolic pressure (LVEDP) decreased during alamandine infusion; this effect was reduced by PD123319. In the normotensive rats, alamandine increased MAP, LVSP, dP/dt (max), and it decreased LVEDP during the infusion period. These effects of alamandine were reduced by losartan.. The results of this investigation suggest that, under normal conditions, alamandine acts via AT1R, but in pathological conditions such as hypertension, its effect on PD123319-sensitive receptors masks its effect on AT1R.

Topics: Animals; Disease Models, Animal; Hypertension; Kidney; Male; Oligopeptides; Rats; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Renin-Angiotensin System

Novel treatments are necessary to reduce the burden of cardiovascular disease (CVD). Alamandine binds to MrgD and is reported to induce vasodilation via stimulation of endothelial nitric oxide synthase (eNOS), but its role in atherogenic blood vessels is yet to be determined. To determine the vasoactive role of alamandine and its precursor AngA in diseased aorta, New Zealand White rabbits were fed a diet containing 1% methionine + 0.5% cholesterol + 5% peanut oil for 4 weeks (MC, n = 5) or control (n = 6). In abdominal aorta, alamandine (1 μM) was added 30 min before a dose-response curve to angiotensin II or AngA (1 nM-1 μM), and immunohistochemistry was used to identify MrgD receptors and eNOS. The thoracic aorta, renal, carotid and iliac arteries were mounted in organ baths. Rings were precontracted with phenylephrine, then a bolus dose of alamandine (1 μM) was added 10 min before a dose-response curve to acetylcholine (0.01 μM-10 μM). The MrgD receptor was localized to normal and diseased aorta and colocalized with eNOS. In control but not diseased blood vessels, alamandine enhanced acetylcholine-mediated vasodilation in the thoracic aorta and the iliac artery (P < 0.05) and reduced it in the renal artery (P < 0.05). In control abdominal aorta, AngA evoked less desensitization than AngII (P < 0.05) and alamandine reduced AngA-mediated vasoconstriction (P < 0.05). In MC, AngA constriction was markedly reduced vs. control (P < 0.05). The vasoactivity of alamandine and AngA are reduced in atherogenesis. Its role in the prevention of CVD remains to be validated.

Topics: Acetylcholine; Angiotensin I; Angiotensins; Animals; Aorta, Abdominal; Aorta, Thoracic; Atherosclerosis; Carotid Arteries; Disease Models, Animal; Dose-Response Relationship, Drug; Iliac Artery; Male; Nitric Oxide Synthase Type III; Oligopeptides; Peptide Fragments; Phenylephrine; Rabbits; Receptors, G-Protein-Coupled; Renal Artery; Vasoconstriction; Vasodilation