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Angiotensin-II is a key factor in renal fibrosis. Obstructive nephropathy induces an isoform shift from catalytic Ampkα2 towards Ampkα1 which contributes to signaling involved in renal tissue injury. The present study explored whether the Ampkα1 isoform contributes to the renal effects of angiotensin-II. To this end, angiotensin-II was infused by subcutaneous implantation of osmotic minipumps in gene-targeted mice lacking functional Ampkα1 (Ampkα1 −/− ) and corresponding wild-type mice (Ampkα1 +/+ ). Western blotting and qRT-PCR were employed to determine protein abundance and mRNA levels, respectively, in renal tissue. In Ampkα1 +/+ mice, angiotensin-II increased renal Ampkα1 protein expression without significantly modifying renal Ampkα2 protein expression. The renal phosphorylated Ampkα (Thr 172 ) protein abundance was not affected by angiotensin-II in neither genotypes, but was significantly lower in Ampkα1 −/− mice than Ampkα1 +/+ mice. Angiotensin-II increased the phosphorylation of Tak1 (Ser 412 ) in renal tissue of Ampkα1 +/+ mice, an effect virtually absent in the Ampkα1 −/− mice. Furthermore, angiotensin-II treatment significantly increased renal protein and mRNA expression of α-smooth muscle actin (αSma) as well as Tak1-target gene expression: Cox2 , Il6 and Pai1 in Ampkα1 +/+ mice, all effects significantly less pronounced in Ampkα1 −/− mice. In conclusion, angiotensin-II up-regulates the Ampkα1 isoform in renal tissue. Ampkα1 participates in renal Tak1 activation and Tak1-dependent signaling induced by angiotensin-II. [ABSTRACT FROM AUTHOR]

AMP-activated protein kinase (Ampk) regulates myocardial energy metabolism and plays a crucial role in the response to cell stress. In the failing heart, an isoform shift of the predominant Ampkα2 to the Ampkα1 was observed. The present study explored possible isoform specific effects of Ampkα1 in cardiomyocytes. To this end, experiments were performed in HL-1 cardiomyocytes, as well as in Ampkα1-deficient and corresponding wild-type mice and mice following AAV9-mediated cardiac overexpression of constitutively active Ampkα1. As a result, in HL-1 cardiomyocytes, overexpression of constitutively active Ampkα1 increased the phosphorylation of Pkcζ. Constitutively active Ampkα1 further increased AP-1-dependent transcriptional activity and mRNA expression of the AP-1 target genes c-Fos , Il6 and Ncx1 , effects blunted by Pkcζ silencing. In HL-1 cardiomyocytes, angiotensin-II activated AP-1, an effect blunted by silencing of Ampkα1 and Pkcζ, but not of Ampkα2. In wild-type mice, angiotensin-II infusion increased cardiac Ampkα1 and cardiac Pkcζ protein levels, as well as c-Fos , Il6 and Ncx1 mRNA expression, effects blunted in Ampkα1-deficient mice. Pressure overload by transverse aortic constriction (TAC) similarly increased cardiac Ampkα1 and Pkcζ abundance as well as c-Fos , Il6 and Ncx1 mRNA expression, effects again blunted in Ampkα1-deficient mice. AAV9-mediated cardiac overexpression of constitutively active Ampkα1 increased Pkcζ protein abundance and the mRNA expression of c-Fos , Il6 and Ncx1 in cardiac tissue. In conclusion, Ampkα1 promotes myocardial AP-1 activation in a Pkcζ-dependent manner and thus contributes to cardiac stress signaling. [ABSTRACT FROM AUTHOR]

Angiotensin- II (Ang- II) infusion is associated with the development of interstitial fibrosis in both heart and kidney as a result of chemokine-dependent uptake of monocytes and subsequent development of myeloid fibroblasts. This study emphasizes on the synergistic role of tumor necrosis factor ( TNF) on the time course of Ang- II-induced fibrosis and inflammation in heart and kidney. In wild-type ( WT) hearts, Ang- II-induced fibrosis peaked within 1 week of infusion and remained stable over a 6-week period, while the myeloid fibroblasts disappeared; TNF receptor-1-knockout ( TNFR1- KO) hearts did not develop a myeloid response or cardiac fibrosis during this time. WT hearts developed more accelerated cardiac hypertrophy and remodeling than TNFR1- KO. In the kidney, 1-week Ang- II infusion did not evoke a fibrotic response; however, after 6 weeks, WT kidneys displayed modest but significant tubulointerstitial collagen deposition associated with the appearance of myeloid cells and profibrotic gene activation. Renal fibrosis was not seen in Ang- II-infused TNFR1- KO. By contrast, while hypertension increased and cardiac function decreased more slowly in TNFR1- KO than WT, they were equivalently abnormal at 6 weeks. Similarly, serum markers for renal dysfunction were not different after 6 weeks. In conclusion, Ang- II infusion initiated fibroinflammatory responses with different time courses in heart and kidney, both requiring TNFR1 signaling, and both associated with monocyte-derived myeloid fibroblasts. TNFR1 deletion obviated the fibroinflammatory effects of Ang- II, but did not alter changes in blood pressure and cardiorenal function after 6 weeks. Thus, the synergy of TNF with Ang- II targets the fibroinflammatory component of Ang- II signaling. [ABSTRACT FROM AUTHOR]

Renal artery stenosis is frequently associated with resistant hypertension, which is defined as failure to normalize blood pressure (BP) even when combined drugs are used. Inhibition of PDE5 by sildenafil has been shown to increase endothelial function and decrease blood pressure in experimental models. However, no available study evaluated the baroreflex sensitivity nor autonomic balance in renovascular hypertensive rats treated with sildenafil. In a translational medicine perspective, our hypothesis is that sildenafil could improve autonomic imbalance and baroreflex sensitivity, contributing to lower blood pressure. Renovascular hypertensive 2-kidney-1-clip (2K1C) and sham rats were treated with sildenafil (45 mg/Kg/day) during 7 days. At the end of treatment, BP and heart rate (HR) were recorded in conscious rats after a 24-h-recovery period. Spontaneous and drug-induced baroreflex sensitivity and autonomic tone were evaluated; in addition, lipid peroxidation was measured in plasma samples. Treatment was efficient in increasing both spontaneous and induced baroreflex sensitivity in treated hypertensive animals. Inhibition of PDE5 was also capable of ameliorating autonomic imbalance in 2K1C rats and decreasing systemic oxidative stress. Taken together, these beneficial effects resulted in significant reductions in BP without affecting HR. We suggest that sildenafil could be considered as a promising alternative to treat resistant hypertension. [ABSTRACT FROM AUTHOR]

Cardiac hypertrophy is accompanied by excessive collagen deposition in the heart. Despite painstaking research on this fatal disease, the precise role of molecular chaperones in myocardial fibrosis has not yet been elucidated. In this study, we have analyzed the mechanism by which Heat shock protein 90 (Hsp90)/Cell division cycle 37 (Cdc37) assembly modulates cardiac hypertrophy associated fibrosis. For the in vitro hypertrophy model, Angiotensin II (AngII) treated cultured adult cardiac fibroblasts were used, whereas the in vivo hypertrophy model was generated by renal artery ligation in adult male Wistar rats ( Rattus norvegicus ). Pretreatment with the Hsp90 inhibitor or the blocking of Hsp90-Cdc37 interactions during pressure overload hypertrophy resulted in ubiquitin-mediated proteasomal degradation of TGFβ receptor-II (TβR-II) leading to termination of TGFβ mediated signaling. In both cases significant reduction in collagen synthesis was observed revealing the Hsp90/Cdc37 complex as an integral profibrotic component of TGFβ signaling during cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

Vascular dysfunction induced by angiotensin-II can result from direct effects on vascular and inflammatory cells and indirect hemodynamic effects. Using isolated and functional cultured aortas, we aimed to identify the effects of angiotensin-II on cyclooxygenase (COX) and inducible nitric oxide synthase (iNOS) and evaluate their impact on vascular reactivity. Aortic rings from mice were incubated overnight in culture medium containing angiotensin-II (100 nmol/L) or vehicle to induce vascular disfunction. Vascular reactivity of cultured arteries was evaluated in a bath chamber. Immunofluorescence staining for COX-1 and COX-2 was performed. Nitric oxide (NO) formation was approached by the levels of nitrite, a NO end product, and using a fluorescent probe (DAF). Oxidative and nitrosative stress were determined by DHE fluorescence and nitrotyrosine staining, respectively. Arteries cultured with angiotensin-II showed impairment of endothelium-dependent relaxation, which was reversed by the AT 1 receptor antagonist. Inhibition of COX and iNOS restored vascular relaxation, suggesting a common pathway in which angiotensin-II triggers COX and iNOS, leading to vasoconstrictor receptors activation. Moreover, using selective antagonists, TP and EP were identified as the receptors involved in this response. Endothelium-dependent contractions of angiotensin-II-cultured aortas were blunted by ibuprofen, and increased COX-2 immunostaining was found in the arteries, indicating endothelium release of vasoconstrictor prostanoids. Angiotensin-II induced increased reactive oxygen species and NO production. An iNOS inhibitor prevented NO enhancement and nitrotyrosine accumulation in arteries stimulated with angiotensin-II. These results confirm that angiotensin-II causes vascular inflammation that culminates in endothelial dysfunction in an iNOS and COX codependent manner. [Display omitted] • Ang-II-induced endothelial dysfunction in cultured aortas is dependent of both iNOS and COX. • An endothelium-derived constrictor prostanoid accounts for Ang-II-induced impaired relaxation. • Ang-II increased NO and nitrosylation in an iNOS-dependant manner in the aortas. • Ang-II trigger an iNOS/COX interplay regardless of cell recruitment or hemodynamic. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S), carbon monoxide (CO) and nitric oxide (NO) share signaling and vasorelaxant properties and are involved in proliferation and apoptosis. Inhibiting NO production or availability induces hypertension and proteinuria, which is prevented by concomitant blockade of the H 2 S producing enzyme cystathionine γ-lyase (CSE) by d , l -propargylglycine (PAG). We hypothesized that blocking H 2 S production ameliorates Angiotensin II (AngII)-induced hypertension and renal injury in a rodent model. Effects of concomitant administration of PAG or saline were therefore studied in healthy (CON) and AngII hypertensive rats. In CON rats, PAG did not affect systolic blood pressure (SBP), but slightly increased proteinuria. In AngII rats PAG reduced SBP, proteinuria and plasma creatinine (180 ± 12 vs. 211 ± 19 mmHg; 66 ± 35 vs. 346 ± 92 mg/24 h; 24 ± 6 vs. 47 ± 15 μmol/L, respectively; p < 0.01). Unexpectedly, kidney to body weight ratio was increased in all groups by PAG (p < 0.05). Renal injury induced by AngII was reduced by PAG (p < 0.001). HO-1 gene expression was increased by PAG alone (p < 0.05). PAG increased inner cortical tubular cell proliferation after 1 week and decreased outer cortical tubular nucleus number/field after 4 weeks. In vitro proximal tubular cell size increased after exposure to PAG. In summary, blocking H 2 S production with PAG reduced SBP and renal injury in AngII infused rats. Independent of the cardiovascular and renal effects, PAG increased HO-1 gene expression and kidney weight. PAG alone increased tubular cell size and proliferation in-vivo and in-vitro . Our results are indicative of a complex interplay of gasotransmitter signaling/action of mutually compensatory nature in the kidney. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor (VEGF) and Angiotensin II (Ang-II) are important in glomerulosclerosis, which is one of the main causes of chronic kidney disease. Previous studies have demonstrated that angiotensin type 1 receptor blocker (ARB) can inhibit the synthesis of VEGF mediated by Ang-II and can effectively treat diabetic nephropathy. In the present study, the expression of VEGF and its receptors (VEGFR1/VEGFR2) was examined in Ang-II stimulated podocytes, which were treated with SU5416, a specific VEGFR2 inhibitor. The protein expression of synaptopodin, VEGFR1/2, phosphorylated VEGFR2 and extracellular signal-regulated kinases (ERK) was assessed by western blot analysis. The mRNA expression of transforming growth factor (TGF)-β1 was examined by reverse transcription-quantitative polymerase chain reaction. It was observed that Ang-II increased the expression of VEGF-A and VEGFR2. Simultaneously, the increased expression of phosphorylated (p-)VEGFR2 and p-ERK induced by Ang-II was downregulated by SU5416. SU5416 can decrease the expression of synaptopodin and increase the expression of TGF-β1 induced by Ang-II as well as ARB treatment. The expression of VEGFR1 remained unchanged by either Ang-II or SU5416 treatment. However, the normal podocytes administered SU5416 alone showed low levels of synaptopodin and high expression of TGF-β1 compared with the control. In conclusion, VEGF-A/VEGFR2 may be essential for podocytes in a normal state. It is suggested that blockade of VEGF-A/VEGFR2 may exhibit a protective effect on Ang-II stimulated podocytes. [ABSTRACT FROM AUTHOR]

The objective of our study is to investigate the effect of triptolide on expression of thrombospondin-1 and transforming growth factor β1 in renal tubular cells. Human renal tubular epithelial cells were stimulated by different concentrations of triptolide (0.1, 1, and 10 μg/L) in the presence of angiotensin-II (10−7 mol/L). Real Time PCR was used to detect the mRNA expression of thrombospondin-1 and transforming growth factor β1. Western blot analysis was used to detect the protein expression. ELISA was used to detect the level of total and active transforming growth factor β1. The mRNA expression of thrombospondin-1 (3.66 ± 0.48 vs. 1.33 ± 0.26,p < 0.05) and transforming growth factor β1 (3.58 ± 0.59 vs. 1.26 ± 0.28,p < 0.05) were up-regulated obviously when stimulated by angiotensin-II. And the protein expression of thrombospondin-1 (0.5126 ± 0.0936 vs. 0.1025 ± 0.0761,p < 0.01) and transforming growth factor β1 (0.5948 ± 0.0736 vs. 0.1318 ± 0.0614,p < 0.01) were also up-regulated simultaneously when stimulated by angiotensin-II. The expression of thrombospondin-1 and transforming growth factor β1 induced by angiotensin-II were down-regulated markedly with 1 μg/L and 10 μg/L of triptolide in mRNA and protein levels (p < 0.05,p <  0.01). And triptolide (1 and 10 μg/L) could reduce the expression of total and active transforming growth factor β1 (p < 0.05,p < 0.01). In conclusion, triptolide can inhibit the expression of thrombospondin-1 and transforming growth factor β1 in mRNA and protein levels and down-regulate the levels of total and active transforming growth factor β1. [ABSTRACT FROM AUTHOR]

Simple and sensitive Liquid Chromatography-Tandem Mass Spectrometry (LCMS/MS) method was developed and validated, then was implicated on hypertensive human subjects to study drug interaction of atorvastatin (ATVS) and Olmesartan (OLM) on status of Angiotensin-II (ANG-II). The ANG-II in plasma was extracted with 5 mL methanol containing 5 % formic acid through C (cartridges) liquid-liquid extraction, dried and reconstituted with 1 mL of 16 % acetonitrile in 0.1 % formic acid in water. The chromatographic separation of ANG-II with a Agilent technology 6410 Triple quadrupole was carried multiple reaction monitoring scan mode with a Agilent 1290 Infinity LC system for UHPLC. The sample were separated on a (Thermo Scientific) Hy-Purity advance (50 × 4.6 mm, 5 μm) using Mobile Phase A: 16 % acetonitrile in 0.1 % formic acid in water and Mobile Phase B: 0.1 % formic acid in methanol at a flow rate of 0.3 mL/min, performed at ambient temperature. The mobile phase gradient of 16 % acetonitrile in water was linearly increased to 38 % acetonitrile over 10 min and subsequently the mobile-phase was increased to 100 % acetonitrile over 15 min. The developed method was validated for specificity, accuracy, precision, stability, linearity, sensitivity and recovery. The method was linear between peak area ratio of standard and internal standard over the range of 50-800 ng/mL. The method was successfully applied for the drug interaction study revealed levels of ANG-II were significantly higher in ATVS + OLM treatment condition as compared to individual treatment of OLM. This reflects the reason of low effectiveness of ATVS + OLM in combination instead of synergistic activity. [ABSTRACT FROM AUTHOR]

Connective tissue growth factor ( CTGF) induces extracellular matrix ( ECM) synthesis and contractility in human trabecular meshwork ( HTM) cells. Both processes are involved in the pathogenesis of primary open-angle glaucoma. To date, little is known about regulation and function of CTGF expression in the trabecular meshwork ( TM). Therefore, we analysed the effects of different aqueous humour proteins and stressors on CTGF expression in HTM cells. HTM cells from three different donors were treated with endothelin-1, insulin-like growth factor ( IGF)-1, angiotensin-II, H2O2 and heat shock and were analysed by immunohistochemistry, real-time RT- PCR and Western blotting. Viability after H2O2 treatment was measured in CTGF silenced HTM-N cells and their controls. Latrunculin A reduced expression of CTGF by about 50% compared to untreated HTM cells, whereas endothelin-1, IGF-1, angiotensin-II, heat shock and oxidative stress led to a significant increase. Silencing of CTGF resulted in a delayed expression of αB-crystallin and in reduced cell viability in comparison to the controls after oxidative stress. Conversely, CTGF treatment led to a higher cell viability rate after H2O2 treatment. CTGF expression is induced by factors that have been linked to glaucoma. An increased level of CTGF appears to protect TM cells against damage induced by stress. The beneficial effect of CTGF for viability of TM cells is likely associated with the effects on increased ECM synthesis and higher contractility of the TM, thereby contributing to reduced aqueous humour outflow facility causing increased intraocular pressure. [ABSTRACT FROM AUTHOR]

Ample genetic and physiological evidence establishes that renal salt handling is a critical regulator of blood pressure. Studies also establish a role for the immune system, T-cell infiltration, and immune cytokines in hypertension. This study aimed to connect immune cytokines, specifically interferon-γ (IFN-γ) and interleukin-17A (IL-17A), to sodium transporter regulation in the kidney during angiotensin-II (Ang-II) hypertension. C57BL/6J (wild-type) mice responded to Ang-II infusion (490 ng/kg per minute, 2 weeks) with a rise in blood pressure (170 mm Hg) and a significant decrease in the rate of excretion of a saline challenge. In comparison, mice that lacked the ability to produce either IFN-γ (IFN-γ-/-) or IL-17A (IL-17A-/-) exhibited a blunted rise in blood pressure (<150 mm Hg), and both the genotypes maintained baseline diuretic and natriuretic responses to a saline challenge. Along the distal nephron, Ang-II infusion increased abundance of the phosphorylated forms of the Na-K-2Cl cotransporter, Na-Cl cotransporter, and Ste20/SPS-1- related proline-alanine-rich kinase, in both the wild-type and the IL-17A-/- but not in IFN-γ-/- mice; epithelial Na channel abundance increased similarly in all the 3 genotypes. In the proximal nephron, Ang-II infusion significantly decreased abundance of Na/H-exchanger isoform 3 and the motor myosin VI in IL-17A-/- and IFN-γ-/-, but not in wild-type; the Na-phosphate cotransporter decreased in all the 3 genotypes. Our results suggest that during Ang-II hypertension both IFN-γ and IL-17A production interfere with the pressure natriuretic decrease in proximal tubule sodium transport and that IFN-γ production is necessary to activate distal sodium reabsorption. [ABSTRACT FROM AUTHOR]

Background: This research investigated the response of vascular active factors, vascular endothelial growth factor (VEGF) and angiotensin-II (AT-II) to ovarian stimulation during 24 hours in patients with polycystic ovary syndrome (PCOS). Materials and Methods: In this clinical trial study, 52 patients with PCOS and 8 control cases were stimulated with human chorionic gonadotropin (HCG) on the 4th to 7th day of the patients’ natural or induced menstrual cycles. We measured VEGF and AT-II by radioimmunoassay before the injection (0 hour) and 3, 8, 12, 18 and 24 hours after the stimulation. Results: After ovarian stimulation, there was substantially higher level of VEGF in typical PCOS patients than the other three groups at the 3 hour time point (p<0.05), while there were no significant differences in VEGF at all the other time points among the four groups. As for AT-II, before and at all time points after the ovarian stimulation, it seemed that the AT-II levels in patients’ sera with different phenotypes of PCOS by the Rotterdam criteria were all higher than in the control group although the differences were not statistically significant. The level of AT-II in typical PCOS patients was also significantly higher than the other three groups at the 3 hour time point (p<0.05), while no significant differences at all the other time points among the four groups were observed. Conclusion: The response to the stimulation varied among patients with different phenotypes of PCOS according to the Rotterdam criteria. Serum VEGF and AT-II were possible contributors to an increased risk of developing ovarian hyperstimulation syndrome (OHSS) in patients with typical PCOS during the early follicular phase (3 hours) after ovarian stimulation (Registration Number: NCT02265861). [ABSTRACT FROM AUTHOR]

An imbalance in the circulatory and organ-specific renin-angiotensin system (RAS) pathways is associated with age-related dysfunction and disease including cardiovascular burden and more recently Alzheimer's disease (AD). It is currently unclear whether an age-associated imbalance in components of the RAS within the brain precedes the onset of AD or whether a RAS imbalance is associated with the onset of disease pathology and cognitive decline. Angiotensin-converting enzyme-1 (ACE-1) and -2 (ACE-2) protein (ELISA) and enzyme activity (FRET assay), markers of the classical and counter-regulatory RAS axis respectively, and Ang-II and Ang-(1-7) peptide levels (ELISA), were measured in the left cortex across four transgenic AD mouse models of amyloid pathology (5xFAD - 2, 6, and 12 months of age; Apd9 - 3-4, 12, and 18 months of age; Tg2576 - 3-4 and 24 months of age; and PDAPP - 3-4, 7, 11, 15, and 18 months of age) and littermate wild-type (WT) controls. ACE-1 level, and enzyme activity, was unaltered in relation to age in WT mice and across all four models. In contrast, ACE-2 level and enzyme activity, was reduced and Ang-II increased with ageing in both WT animals and disease models. The changes in ACE-2 and Ang-II in AD models mirrored WT mice, except for the 5xFAD model, when the reduction in ACE-2 (and elevated Ang-II) was observed at a younger age. These data indicate an age-related dysregulation of brain RAS is likely to be driven by a reduction in ACE-2. The reduction in ACE-2 occurs at a young age, coinciding with early pathological changes and the initial deposition of Aβ, and preceding neuronal loss and cognitive decline, in the transgenic AD models. However, the age-related loss was mirrored in WT mice suggesting that the change was independent of pathological Aβ deposition., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

We hypothesized that, due to a cross-talk between cytoplasmic O2--sources and intraluminally expressed xanthine oxidase (XO), intraluminal O2- is instrumental in mediating intraluminal (endothelial dysfunction) and cytosolic (p38 and ERK1/2 MAPKs phosphorylation) manifestations of vascular oxidative stress induced by endothelin-1 (ET-1) and angiotensin II (AT-II). Isolated guinea-pig hearts were subjected to 10-min agonist perfusion causing a burst of an intraluminal O2-. ET-1 antagonist, tezosentan, attenuated AT-II-mediated O2-, indicating its partial ET-1 mediation. ET-1 and Ang-T (AT-II + tezosentan) triggered intraluminal O2-, endothelial dysfunction, MAPKs and p47phox phosphorylation, and NADPH oxidase (Nox) and XO activation. These effects were: (i) prevented by blocking PKC (chelerythrine), Nox (apocynin), mitochondrial ATP-dependent K+ channel (5-HD), complex II (TTFA), and XO (allopurinol); (ii) mimicked by the activation of Nox (NADH); and mitochondria (diazoxide, 3-NPA) and (iii) the effects by NADH were prevented by 5-HD, TTFA and chelerythrine, and those by diazoxide and 3-NPA by apocynin and chelerythrine, suggesting that the agonists coactivate Nox and mitochondria, which further amplify their activity via PKC. The effects by ET-1, Ang-T, NADH, diazoxide, and 3-NPA were opposed by blocking intraluminal O2- (SOD) and XO, and were mimicked by XO activation (hypoxanthine). Apocynin, TTFA, chelerythrine, and SOD opposed the effects by hypoxanthine. In conclusion, oxidative stress by agonists involves cellular inside-out and outside-in signaling in which Nox-mitochondria-PKC system and XO mutually maintain their activities via the intraluminal O2-. [ABSTRACT FROM AUTHOR]

Cathepsin G (CatG), a serine protease present in mast cells and neutrophils, can produce angiotensin-II (Ang-II) and degrade elastin. Here we demonstrate increased CatG expression in smooth muscle cells (SMCs), endothelial cells (ECs), macrophages, and T cells from human atherosclerotic lesions. In low-density lipoprotein (LDL) receptor-deficient ( Ldlr –/– ) mice, the absence of CatG reduces arterial wall elastin degradation and attenuates early atherosclerosis when mice consume a Western diet for 3 months. When mice consume this diet for 6 months, however, CatG deficiency exacerbates atherosclerosis in aortic arch without affecting lesion inflammatory cell content or extracellular matrix accumulation, but raises plasma total cholesterol and LDL levels without affecting high-density lipoprotein (HDL) or triglyceride levels. Patients with atherosclerosis also have significantly reduced plasma CatG levels that correlate inversely with total cholesterol (r = –0.535, P < 0.0001) and LDL cholesterol (r = –0.559, P < 0.0001), but not with HDL cholesterol ( P = 0.901) or triglycerides ( P = 0.186). Such inverse correlations with total cholesterol (r = –0.504, P < 0.0001) and LDL cholesterol (r = –0.502, P < 0.0001) remain significant after adjusting for lipid lowering treatments among this patient population. Human CatG degrades purified human LDL, but not HDL. This study suggests that CatG promotes early atherogenesis through its elastinolytic activity, but suppresses late progression of atherosclerosis by degrading LDL without affecting HDL or triglycerides. [ABSTRACT FROM AUTHOR]

Background: Given the well-documented adverse side effects of sorafenib, many sorafenib-treated patients may need the reduced initial dose of the compound, and an alternative sorafenib-based therapy, which exerts similar clinical benefit, is anticipated. An angiostatic therapy with sorafenib is considered one of the promising approaches for chemoprevention of hepatocellular carcinoma. The aim of the current study was to elucidate the combination effect of low dose of sorafenib and angiotensin-II receptor blocker (ARB) on hepatocarcinogenesis, especially in conjunction with angiogenesis. Methods: The chemopreventive effect on the development of liver preneoplastic lesions, angiogenesis, and several indices was elucidated in rats. We also performed several sets of in vitro experiments to examine the mechanisms involved. Results: Using a non-diabetic rat model of steatohepatitis with choline deficient l-amino acid-defined diet, sorafenib demonstrated marked inhibition of preneoplastic lesions in a dose dependent manner. Combined treatment with ARB (losartan) at a clinically comparable dose and half dose of sorafenib resulted in the inhibitory effect equivalent to that of common dose of sorafenib along with suppression of hepatic neovascularization and potent angiogenic factor, vascular endothelial growth factor. Furthermore, similar combined inhibitory outcomes were observed in several sets of in vitro studies. Conclusion: Since the combinatorial treatment using low doses of sorafenib and ARB could sufficiently induce inhibitory effect on the development of preneoplastic lesions at the magnitude similar to the conventional dose of sorafenib, this regimen may provide new strategy for patients intolerant of the usual dose of sorafenib in the future. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the most common cause of dementia, affecting more than 36 million people worldwide. AD is characterized by a progressive loss of cognitive functions. For years, it has been thought that age is the main risk factor for AD. Recent studies suggest that life style factors, including nutritional behaviors, play a critical role in the onset of dementia. Evidence about the relationship between nutritional behavior and AD includes the role of conditions such as obesity, hypertension, dyslipidemia and elevated glucose levels. The coexistence of some of these cardio-metabolic risk factors is generally known as metabolic syndrome (MS). Some clinical studies support the role of MS in the onset of AD. However, the cross-talk between the molecular signaling implicated in these disorders is unknown. In the present review, we focus on the molecular correlates that support the relationship between MS and the onset of AD. We also discuss relevant issues such as the role of leptin, insulin and renin–angiotensin signaling in the brain and the possible role of Wnt signaling in both MS and AD. We discuss the evidence supporting the use of ob / ob mice, high-fructose diets, aortic coarctation-induced hypertension and Octodon degus , which spontaneously develops β-amyloid deposits and metabolic derangements, as suitable animal models to address the relationships between MS and AD. Finally, we examine emergent data supporting the role of Wnt signaling in the modulation of AD and MS, implicating this pathway as a therapeutic target in both conditions. [ABSTRACT FROM AUTHOR]

Objectives The inhibition of the renal renin-angiotensin system by the active form of vitamin D contributes to the cardiovascular health benefits of a normal vitamin D status. Local production of angiotensin-II in the vascular wall is a potent mediator of oxidative stress, prompting premature senescence. Herein, our objective was to examine the impact of defective vitamin D signalling on local angiotensin-II levels and arterial health. Methods Primary cultures of aortic vascular smooth muscle cells (VSMC) from wild-type and vitamin D receptor-knockout (VDRKO) mice were used for the assessment of cell growth, angiotensin-II and superoxide anion production and expression levels of cathepsin D, angiotensin-II type 1 receptor and p57Kip2. The in vitro findings were confirmed histologically in aortas from wild-type and VDRKO mice. Results VSMC from VDRKO mice produced more angiotensin-II in culture, and elicited higher levels of cathepsin D, an enzyme with renin-like activity, and angiotensin-II type 1 receptor, than wild-type mice. Accordingly, VDRKO VSMC showed higher intracellular superoxide anion production, which could be suppressed by cathepsin D, angiotensin-II type 1 receptor or NADPH oxidase antagonists. VDRKO cells presented higher levels of p57Kip2, impaired proliferation and premature senescence, all of them blunted upon inhibition of angiotensin-II signalling. In vivo studies confirmed higher levels of cathepsin D, angiotensin-II type 1 receptor and p57Kip2 in aortas from VDRKO mice. Conclusion The beneficial effects of active vitamin D in vascular health could be a result of the attenuation of local production of angiotensin-II and downstream free radicals, thus preventing the premature senescence of VSMC. [ABSTRACT FROM AUTHOR]

Angiotensin-II production in the subfornical organ acting through angiotensin-II type-1 receptors is necessary for polydipsia, resulting from elevated renin-angiotensin system activity. Protein kinase C and mitogen-activated protein kinase pathways have been shown to mediate effects of angiotensin-II in the brain. We investigated mechanisms that mediate brain angiotensin-II-induced polydipsia. We used double-transgenic sRA mice, consisting of human renin controlled by the neuron-specific synapsin promoter crossed with human angiotensinogen controlled by its endogenous promoter, which results in brain-specific overexpression of angiotensin-II, particularly in the subfornical organ. We also used the deoxycorticosterone acetate-salt model of hypertension, which exhibits polydipsia. Inhibition of protein kinase C, but not extracellular signal-regulated kinases, protein kinase A, or vasopressin V₁A and V₂ receptors, corrected the elevated water intake of sRA mice. Using an isoform selective inhibitor and an adenovirus expressing dominant negative protein kinase C-α revealed that protein kinase C-α in the subfornical organ was necessary to mediate elevated fluid and sodium intake in sRA mice. Inhibition of protein kinase C activity also attenuated polydipsia in the deoxycorticosterone acetate-salt model. We provide evidence that inducing protein kinase C activity centrally is sufficient to induce water intake in water-replete wild-type mice, and that cell surface localization of protein kinase C-α can be induced in cultured cells from the subfornical organ. These experimental findings demonstrate a role for central protein kinase C activity in fluid balance, and further mechanistically demonstrate the importance of protein kinase C-α signaling in the subfornical organ in fluid intake stimulated by angiotensin-II in the brain. [ABSTRACT FROM AUTHOR]

Angiotensin-II production in the subfornical organ acting through angiotensin-II type-1 receptors is necessary for polydipsia, resulting from elevated renin-angiotensin system activity. Protein kinase C and mitogen-activated protein kinase pathways have been shown to mediate effects of angiotensin-II in the brain. We investigated mechanisms that mediate brain angiotensin-II-induced polydipsia. We used double-transgenic sRA mice, consisting of human renin controlled by the neuron-specific synapsin promoter crossed with human angiotensinogen controlled by its endogenous promoter, which results in brain-specific overexpression of angiotensin-II, particularly in the subfornical organ. We also used the deoxycorticosterone acetate-salt model of hypertension, which exhibits polydipsia. Inhibition of protein kinase C, but not extracellular signal-regulated kinases, protein kinase A, or vasopressin V1A and V, receptors, corrected the elevated water intake of sRA mice. Using an isoform selective inhibitor and an adenovirus expressing dominant negative protein kinase C-a revealed that protein kinase C-a in the subfornical organ was necessary to mediate elevated fluid and sodium intake in sRA mice. Inhibition of protein kinase C activity also attenuated polydipsia in the deoxycorticosterone acetate-salt model. We provide evidence that inducing protein kinase C activity centrally is sufficient to induce water intake in water-replete wild-type mice, and that cell surface localization of protein kinase C-a can be induced in cultured cells from the subfornical organ. These experimental findings demonstrate a role for central protein kinase C activity in fluid balance, and further mechanistically demonstrate the importance of protein kinase C-a signaling in the subfornical organ in fluid intake stimulated by angiotensin-II in the brain. [ABSTRACT FROM AUTHOR]

Abstract: Ethnopharmacological relevance: Cydonia oblonga Mill. (COM) is used in traditional Uyghur medicine to treat or prevent cardiovascular disease. In a previous study COM leaf extracts were found to be active in renal hypertensive rats (RHR). The present study tests the dose-dependence of the effect of ethanol leaf extracts on hypertension and on biomarkers associated with blood pressure control, such as angiotensin-II (AII), plasma renin activity (PRA), apelin-12 (A), endothelin (ET) and nitric oxide (NO), compared to captopril. Methods: Two-kidney one-clip (2K1C) Goldblatt model rats were divided randomly into six groups: sham, model, captopril 25mg/kg, COM leaf extract 80, 160 and 320mg/kg (n=10 each). Drugs were administered orally daily for eight weeks. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured before treatment and every 2 weeks. Blood and kidney samples were collected after the last treatment to measure AII, PRA, A, ET and NO. Results: RHR had increased blood pressure, AII, A, PRA, ET and decreased NO. Treatment with captopril reduced blood pressure, AII, A, PRA, and ET, though not quite to normal values. COM leaf extracts significantly and dose-dependently reduced blood pressure, AII, A, RA and ET, whereas NO was increased. The highest dose of COM had the same effects as captopril. Conclusion: The effects of COM extracts on blood pressure and biomarkers were dose-dependent and at the highest dose similar to those of captopril. This suggests an action of COM on the renin–angiotensin system, which could explain its antihypertensive effect. [Copyright &y& Elsevier]

Introduction: Infusion of angiotensin-II (Ang-II) in apolipoprotein-E-deficient mice (Apo-E-/-) results in suprarenal abdominal aortic aneurysm (AAA) in 30–85% of cases. This study identifies the apparent mechanism by which some animals do, but others do not, develop AAA in this model. Methods: Male Apo-E-/- mice were infused with Ang-II (n=21) or saline (n=6) and sacrificed at 4 weeks. Aortas were excised, embedded in paraffin, sectioned (250 μm intervals), and stained. Sites of transmedial disruption (TMD) were identified and characterized, and their relationship to the 4 major aortic side branches (celiac, superior mesenteric, and renals) were determined. Results: The frequency of TMDs in Ang-II-infused mice that formed AAA (n=9) was similar to those that did not (n=12) (AAA vs. no-AAA: 25 of 36[69%] vs. 28 of 48[58%] branches, P=.3 by chi-square). All TMDs were at branch points. However, in animals with AAA, the mean maximum length of the TMDs was significantly larger (1.94±1.6 vs. 0.65±0.5mm, P=.007 by Mann Whitney U test), the #mac-2+ macrophages per 0.01mm2 of defect area was greater (32±10 vs. 19±11, P<.02 by Kruskal–Wallis with Conover–Inman post hoc), the % area of attempted repair occupied by collagen was less (17±13% vs. 44±15%, P=.0009 by Mann Whitney U test), and the density of collagen per unit length of media missing was also markedly less (0.13±0.2 vs. 1.14±1.0, P=.0001 by Mann Whitney U test). Conclusions: Reinforcement of transmedial defects at branch points by wall matrix is a key intrinsic player in limiting AAA formation in the Ang-II-infused, Apo E-/- mouse and a potentially important mechanism-based therapeutic target for management of small, slowly progressing aneurysms. [ABSTRACT FROM AUTHOR]

The contribution of the renin-angiotensin system (RAS) to Na+ uptake was investigated in larval zebrafish (Danio rerio). At 4 days post fertilization (dpf), the level of whole-body angiotensin-II (ANG-II) was significantly increased after 1- or 3-h exposure to acidic (pH=4.0) or ion-poor water (20-fold dilution of Ottawa tapwater), suggesting rapid activation of the RAS. Long-term (24 h) treatment of 3 dpf larvae with ANG-I or ANG-II significantly increased Na+ uptake which was accompanied by an increase in mRNA expression of the Na+-Cl- cotransporter (zslc12a10.2). Induction of Na+ uptake by exposure to ANG-I was blocked by simultaneously treating larvae with lisinopril (an angiotensin-converting enzyme inhibitor). Acute (2 h) exposure to acidic water or ion-poor water led to significant increase in Na+ uptake which was partially blocked by the ANG-II receptor antagonist, telmisartan. Consistent with these data, translational knockdown of renin prevented the stimulation of Na+ uptake following exposure to acidic or ion-poor water. The lack of any effects of pharmacological inhibition (using RU486), or knockdown of glucocorticoid receptors on the stimulation of Na+ uptake during acute exposure to acidic or ion-poor environments, indicates that the acute effects of RAS occur independently of cortisol signaling. The results of this study demonstrate that the RAS is involved in Na+ homeostasis in larval zebrafish. [ABSTRACT FROM AUTHOR]

Background Dioscorea opposita Thunb. (Huai Shan Yao, DOT), a common staple food in China, has been used for more than 2000 years in traditional Chinese medicine (TCM) to treat different systemic diseases including hypertension. The objective of this study was to investigate the possible antihypertensive effects of the aqueous extract of (DOT) in renovascular hypertensive rats as well as the mechanism in reducing blood pressure. Methods The two-kidney one-clip (2K1C) Goldblatt model of renovascular hypertension was used in Wistar rats. Rats with captopril, low-dose DOT and high-dose DOT treated 2K1C groups for 6 weeks. The blood pressure, cardiac mass index (heart weight/body weight), plasma level of angiotensin-II (Ang-II), endothelin-1(ET-1), superoxide dismutase (SOD) and malondialdehyde (MDA) were evaluated. Results DOT significantly reduced mean systolic and diastolic blood pressure after treatment. DOT also significantly increased plasma SOD activity but decreased plasma MDA concentration. Renal function was improved with captopril and DOT. DOT reduced plasma Ang-II activity and plasma ET concentration. They couldalso significantly reduce the left ventricular hypertrophy and cardiac mass index. Conclusions Our results suggest that DOT may have an antihypertensive effect on hypertension by inhibit ET-converting enzyme and antioxidant activity, which warrant further exploration. [ABSTRACT FROM AUTHOR]

Aim Renin is a rate-limiting enzyme of the renin-angiotensin system ( RAS), and several reports have shown that renin plays an important role in several pathological processes. Although RAS is known to play a pivotal role in the progression of non-alcoholic steatohepatitis ( NASH), the role of renin is still obscure. The aim of the current study was to examine the effect of the clinically used direct renin inhibitor ( DRI), aliskiren, on the progression of NASH in a rat model. Methods The effects of DRI on the choline-deficient L-amino acid-defined ( CDAA) diet-induced rat NASH model was examined in conjunction with the activated hepatic stellate cells ( Ac- HSC) and neovascularization, both of which are known to play important roles in liver fibrosis development and hepatocarcinogenesis, respectively. Results DRI exerted a marked inhibitory effect against liver fibrosis development and glutathione- S-transferase placental form ( GST- P) positive preneoplastic lesions along with suppression of the Ac- HSC and neovascularization in a dose-dependent manner. DRI also inhibited the hepatic expressions of transforming growth factor-beta 1 ( TGF-beta 1), angiotensin- II ( AT-II) and vascular endothelial growth factor ( VEGF). These results indicated that renin played a pivotal role in the liver fibrosis development and hepatocarcinogenesis of NASH. Conclusion Because DRI is already widely used in the clinical practice with safety, this drug may represent a potential new strategy against the progression of NASH in the future. [ABSTRACT FROM AUTHOR]

Abstract: Several evidences indicate that increased cardiac mitochondrial monoamine oxidase type A (MAO-A) activity associates with a failing phenotype. Till now, the mechanism underlying such relation is largely unknown. We explored the hypothesis that exposure of cardiomyocytes to AT-II caused activation of MAO-A and also of catalase and aldehyde dehydrogenase activities, enzymes involved in degrading MAO's end products. Left ventricular cardiomyocytes were isolated from normoglycemic (N) and streptozotocin-injected (50mg/kg) rats (D) treated or not treated with losartan (20mg/kg/day in drinking water; DLos and NLos, respectively), a type 1 receptor (AT1) antagonist, for 3 weeks. In each group of cells, MAO, catalase and aldehyde dehydrogenase activities were measured radiochemically and spectrophotometrically. The same enzymes were also measured in HL-1 immortalized cardiomyocytes not exposed and exposed to AT-II (100nM for 18h) in the absence and in the presence of irbesartan (1μM), an AT1 antagonist. MAO-A catalase and aldehyde dehydrogenase activities were found significantly higher in D, than in N cells. MAO-A positively correlated with catalase activity in D cells. MAO-A and aldehyde dehydrogenase but not catalase over-activation, were prevented in DLos cells. Similarly, MAO-A activity, but not catalase and aldehyde dehydrogenase increased significantly in HL-1 cells acutely exposed to AT-II and this increase was prevented when irbesartan, an AT1 antagonist was present. Over-activation of cardiomyocyte MAO-A activity is among acute (18h) and short-term (2-weeks of diabetes) cardiac effects of AT-II and a novel target of AT1 antagonists, first line treatments of diabetic cardiomyopathy. [Copyright &y& Elsevier]

Metabolic syndrome is associated with an increased risk of colorectal cancer. This study investigated the impact of hypertension, a component of metabolic syndrome, on azoxymethane (AOM)-induced colorectal carcinogenesis using SHRSP/Izm (SHRSP) non-diabetic/hypertensive rats and SHRSP.Z-Leprfa/IzmDmcr (SHRSP-ZF) diabetic/hypertensive rats. Male 6-week-old SHRSP, SHRSP-ZF, and control non-diabetic/normotensive Wister Kyoto/Izm (WKY) rats were given 2 weekly intraperitoneal injections of AOM (20 mg/kg body weight). Two weeks after the last injection of AOM, the SHRSP and SHRSP-ZF rats became hypertensive compared to the control WKY rats. Serum levels of angiotensin-II, the active product of the renin-angiotensin system, were elevated in both SHRSP and SHRSP-ZF rats, but only the SHRSP-ZF rats developed insulin resistance, dyslipidemia, and hyperleptinemia and exhibited an increase in adipose tissue. The development of AOM-induced colonic preneoplastic lesions and aberrant crypts foci, was significantly accelerated in both SHRSP and SHRSP-ZF hypertensive rats, compared to WKY normotensive rats. Furthermore, induction of oxidative stress and exacerbation of inflammation were observed in the colonic mucosa and systemically in SHRSP and SHRSP-ZF rats. Our findings suggest that hypertension plays a role in the early stage of colorectal carcinogenesis by inducing oxidative stress and chronic inflammation, which might be associated with activation of the renin-angiotensin system. [ABSTRACT FROM AUTHOR]

Aim Both angiotensin- II ( AT-II) and aldosterone ( Ald) play pivotal roles in the pathogenesis of diseases in several organs including the liver. We previously reported that suppression of AT-II and Ald with angiotensin-converting enzyme inhibitor ( ACE- I) and selective Ald blocker ( SAB), respectively, attenuated the rat liver fibrogenesis and hepatocarcinogenesis. The aim of our current study was to elucidate the combined effects of ACE- I and SAB in the progression of a non-diabetic rat model of steatohepatitis, and the possible mechanisms involved. Methods In the choline-deficient L-amino acid-defined ( CDAA) diet-induced model, the effects of ACE- I and SAB on liver fibrosis development and hepatocarcinogenesis were elucidated, especially in conjunction with neovascularization. Results Treatment with both ACE- I and SAB suppressed the development of liver fibrosis and glutathione- S-transferase placental form ( GST- P) positive pre-neoplastic lesions. The combined treatment with both agents exerted more inhibitory effects as compared with either a single agent along with suppression of the activated hepatic stellate cells ( Ac- HSC) and neovascularization, both of which play important roles in these processes. Our in vitro study showed that AT-II type 1 receptor blocker ( ARB) and SAB inhibited Ac- HSC proliferation and in vitro angiogenesis along with suppression of the in vivo studies. Conclusion Dual blockade of AT-II and Ald suppresses the progression of a non-diabetic rat model of steatohepatitis. Because both agents are widely and safely used in clinical practice, this combination therapy could be an effective new strategy against steatohepatitis in the future. [ABSTRACT FROM AUTHOR]

Cardiac hormone atrial natriuretic peptide (ANP) and its receptor natriuretic peptide receptor-A (NPR-A) system acts as an intrinsic negative regulator of abnormal extracellular matrix (ECM) remodeling in the heart. However, the underlying mechanism by which ANP/NPR-A system opposes the ECM remodeling in the diseased heart is not well understood. Here, we investigated the anti-fibrotic mechanism of ANP/NPR-A in fibrotic agonist Angiotensin- II (ANG II)-treated adult cardiac fibroblast (CF) cells. Normal and NPR-A-suppressed adult CF cells were treated with ANG II (10 M) in the presence and absence of ANP (10 M) for 24 h. Total collagen concentration, activity and expression of MMP-2 and MMP-9, and nuclear translocation of Nuclear factor-kappaB (NF-κB-p50) were studied. NPR-A-suppressed adult CF cells exhibited a more pronounced increase in collagen production, ROS generation, and NF-κB-p50 nuclear translocation as compared to adult CF cells treated with agonist alone. ANP co-treatment significantly reverses the agonist-induced above changes in normal adult CF cells, while it failed to reverse the agonist-induced collagen synthesis in the NPR-A-suppressed adult CF cells. The cGMP analog (8-bromo-cGMP) treatment significantly attenuated the agonist-induced collagen synthesis both in normal and NPR-A-suppressed adult cells. The results of this study suggest that ANP/NPR-A signaling system antagonizes the agonist-induced collagen synthesis via suppressing the activities of MMP-2, MMP-9, ROS generation, and NF-κB nuclear translocation mechanism. [ABSTRACT FROM AUTHOR]