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Brain insulin receptor signaling is strongly implicated in cardiovascular and metabolic physiological regulation. In particular, we recently demonstrated that insulin receptors within the subfornical organ (SFO) play a tonic role in cardiovascular and metabolic regulation in mice. The SFO is a forebrain sensory circumventricular organ that regulates cardiometabolic homeostasis due to its direct exposure to the circulation and thus its ability to sense circulating factors, such as insulin. Previous work has demonstrated broad distribution of insulin receptor-expressing cells throughout the entire SFO, indirectly indicating insulin receptor expression in multiple cell types. Based on this, we sought to determine the cellular phenotypes that express insulin receptors within the SFO by combining immunohistochemistry with genetically modified reporter mouse models. Interestingly, SFO neurons, including both excitatory and inhibitory types, were the dominant cell site for insulin receptor expression, although a weak degree of insulin receptor expression was also detected in astrocytes. Moreover, SFO angiotensin type 1a receptor neurons also expressed insulin receptors. Collectively, these anatomical findings indicate the existence of potentially complex cellular networks within the SFO through which insulin signaling can influence physiology and further point to the SFO as a possible brain site for crosstalk between angiotensin-II and insulin. [ABSTRACT FROM AUTHOR]

The hypothalamic paraventricular nucleus (PVN) regulates sympathetic activity and blood pressure. The regulator of G protein signaling 2 (RGS2) is a negative G protein regulator, which selectively regulates Gaq signaling, a potential cause of hypertension. This study aimed to examine angiotensin II (ANG II)-G protein- RGS2 signaling on the central mechanisms of blood pressure control, sympathetic activation, and kidney function. The Sprague Dawley rats were infused with ANG II (200 ng/kg/min) via osmotic mini pump to induce hypertension. Adenovirus (AV) vectors encoding RGS2 was transfected into the PVN in vivo. By radio telemetry measurements, we found AV-RGS2 transfection to the PVN significantly attenuated the increase of mean arterial pressure in ANG II infusion rats from days 2-7 of the 2-week experiment (Day 7: ANG II + AV-RGS2 141.3 ± 10.0 mmHg vs. ANG II 166.9 ± 9.3 mmHg, p < 0.05). AV-RGS2 transfection significantly reduced the serum norepinephrine level and acute volume reflex and increased daily urine volume and sodium excretion in ANG II-infused hypertensive rats. AV-RGS2 transfection significantly reduced Gaq and PKC protein expressions within the PVN in ANG II infusion rats. In cultured mouse hypothalamic cells, real-time PCR study showed ANG II treatment increased mRNA expression of Gaq, Gas, and RGS2, and AV-RGS2 treatment decreased ANG II-induced mRNA expression of Gaq and Gas. Using confocal imagery, we found that AV-RGS2 attenuated the increase of calcium influx in ANG II-treated cells. Our results suggest that central overexpression of RGS2 in the PVN attenuated the increase of blood pressure and sympathetic outflow, and improves kidney excretory function in hypertensive rats. This may be via the alteration of ANG II-G-protein-RGS2 signaling in the central nervous system. [ABSTRACT FROM AUTHOR]

The renin‐angiotensin system (RAS) regulates systemic and cerebral blood flow and is dysregulated in dementia. The major aim of this study was to determine if RAS signalling is dysregulated in vascular dementia. We measured markers of RAS signalling in white matter underlying the frontal and occipital cortex in neuropathologically confirmed cases of vascular dementia (n = 42), Alzheimer's disease (n = 50), mixed AD/VaD (n = 50) and age‐matched controls (n = 50). All cases were stratified according to small vessel disease (SVD) severity across both regions. ACE‐1 and ACE‐2 protein and activity was measured by ELISA and fluorogenic peptide assays respectively, and angiotensin peptide (Ang‐II, Ang‐III and Ang‐(1–7)) levels were measured by ELISA. ACE‐1 protein level and enzyme activity, and Ang‐II and Ang‐III, were elevated in the white matter in vascular dementia in relation to SVD severity. ACE‐1 and Ang‐II protein levels were inversely related to MAG:PLP1 ratio, a biochemical marker of brain tissue oxygenation that when reduced indicates cerebral hypoperfusion, in a subset of cases. ACE‐2 level was elevated in frontal white matter in vascular dementia. Ang‐(1–7) level was elevated across all dementia groups compared to age‐matched controls but was not related to SVD severity. RAS signalling was not altered in the white matter in Alzheimer's disease. In the overlying frontal cortex, ACE‐1 protein was reduced and ACE‐2 protein increased in vascular dementia, whereas angiotensin peptide levels were unchanged. These data indicate that RAS signalling is dysregulated in the white matter in vascular dementia and may contribute to the pathogenesis of small vessel disease. [ABSTRACT FROM AUTHOR]

The hypothalamic paraventricular nucleus (PVN) regulates sympathetic activity and blood pressure. The regulator of G protein signaling 2 (RGS2) is a negative G protein regulator, which selectively regulates G⍺q signaling, a potential cause of hypertension. This study aimed to examine angiotensin II (ANG II)-G protein-RGS2 signaling on the central mechanisms of blood pressure control, sympathetic activation, and kidney function. The Sprague Dawley rats were infused with ANG II (200 ng/kg/min) via osmotic mini pump to induce hypertension. Adenovirus (AV) vectors encoding RGS2 was transfected into the PVN in vivo. By radio telemetry measurements, we found AV-RGS2 transfection to the PVN significantly attenuated the increase of mean arterial pressure in ANG II infusion rats from days 2–7 of the 2-week experiment (Day 7: ANG II + AV-RGS2 141.3 ± 10.0 mmHg vs. ANG II 166.9 ± 9.3 mmHg, p < 0.05). AV-RGS2 transfection significantly reduced the serum norepinephrine level and acute volume reflex and increased daily urine volume and sodium excretion in ANG II-infused hypertensive rats. AV-RGS2 transfection significantly reduced G⍺q and PKC protein expressions within the PVN in ANG II infusion rats. In cultured mouse hypothalamic cells, real-time PCR study showed ANG II treatment increased mRNA expression of G⍺q, G⍺s, and RGS2, and AV-RGS2 treatment decreased ANG II-induced mRNA expression of G⍺q and G⍺s. Using confocal imagery, we found that AV-RGS2 attenuated the increase of calcium influx in ANG II-treated cells. Our results suggest that central overexpression of RGS2 in the PVN attenuated the increase of blood pressure and sympathetic outflow, and improves kidney excretory function in hypertensive rats. This may be via the alteration of ANG II-G-protein-RGS2 signaling in the central nervous system.

BACKGROUND: Among chronic noncommunicable diseases, cardiovascular diseases, particularly coronary heart disease (CHD), are the leading cause of death. The rennin-angiotensin-aldosterone system plays an important role in CHD development and progression; however, its role in the regulation of immunoneuroendocrine interactions requires further analysis. OBJECTIVE: To study the relationship between angiotensin II (AT II) and molecular regulators of the activity of whole blood mononuclear cells (MNCs) in patients with angina pectoris. MATERIALS AND METHODS: This cross-sectional study enrolled 65 patients with exertional angina aged 45–67 years, including 19 apparently healthy individuals. The levels of interleukins (ILs), transforming growth factor-β1 (TGF-β1), prostaglandin E2 (PG E2), serotonin, thyroid-stimulating hormone (TSH), and AT II in the blood serum were determined. In MNCs, the concentrations of protein kinases FAK, JNK, p38, and ERK, signal transducers, and activators of transcription (STAT 3, 5A, and 6) were determined. RESULTS: In patients with coronary artery disease, the production of TGF-β1 increased by 7.2% (p=0.00001), AT II by 136.9% (p=0.0001), serotonin by 129.0% (p=0.00001), IL-18 by 92.5% (p=0.00001), TSH by 51.7% (p=0.0012), ERK protein kinase content by 86.4% (p=0.0001), JNK by 56.8% (p=0.0001), and FAK by 55.3% (p=0.00002). The levels of IL-15 also decreased by 38.1% (p=0.0001), PG E2 by 39.5% (p=0.0001), and STAT3 by 52.5% (p=0.0001). CONCLUSION: The nature of the identified relationships among the analyzed factors allows us to consider AT II as a factor that ensures adaptive coupling of immune and neuroendocrine regulatory mechanisms in patients with coronary artery disease, contributing to a change in the balance between macrophages and T-helper types 1 and 2.

Women who suffered preeclampsia (PE) have two to four times higher risk for development of cardiovascular disease (CVD) compared with women with a history of normotensive pregnancy. Microvascular and endothelial dysfunction, mediated by different vasoactive factors have been suggested as attainable pathophysiological pathways. The study aimed to: (1) determine changes in circulating levels of key vasoactive peptides in sera of women with history of PE and in women who had a normal pregnancy 1 year after delivery and (2) investigate whether an association exists between these molecules and cardiovascular risk factors.

Brain insulin receptor signaling is strongly implicated in cardiovascular and metabolic physiological regulation. In particular, we recently demonstrated that insulin receptors within the subfornical organ (SFO) play a tonic role in cardiovascular and metabolic regulation in mice. The SFO is a forebrain sensory circumventricular organ that regulates cardiometabolic homeostasis due to its direct exposure to the circulation and thus its ability to sense circulating factors, such as insulin. Previous work has demonstrated broad distribution of insulin receptor-expressing cells throughout the entire SFO, indirectly indicating insulin receptor expression in multiple cell types. Based on this, we sought to determine the cellular phenotypes that express insulin receptors within the SFO by combining immunohistochemistry with genetically modified reporter mouse models. Interestingly, SFO neurons, including both excitatory and inhibitory types, were the dominant cell site for insulin receptor expression, although a weak degree of insulin receptor expression was also detected in astrocytes. Moreover, SFO angiotensin type 1a receptor neurons also expressed insulin receptors. Collectively, these anatomical findings indicate the existence of potentially complex cellular networks within the SFO through which insulin signaling can influence physiology and further point to the SFO as a possible brain site for crosstalk between angiotensin-II and insulin.

Background: Endothelial dysfunction (ED) is a marker of vascular damage and a precursor of cardiovascular diseases such as hypertension, which involve inflammation and organ damage. Nitric oxide (NO), produced by eNOS, which is induced by pAKT, plays a crucial role in the function of a healthy endothelium. Methods: A combination of subfractions SF1 and SF3 (C4) of the aqueous fraction from Cucumis sativus (Cs-Aq) was evaluated to control endothelial dysfunction in vivo and on HMEC-1 cells to assess the involvement of pAkt in vitro. C57BL/6J mice were injected daily with angiotensin II (Ang-II) for 10 weeks. Once hypertension was established, either Cs-AqC4 or losartan was orally administered along with Ang-II for a further 10 weeks. Blood pressure (BP) was measured at weeks 0, 5, 10, 15, and 20. In addition, serum creatinine, inflammatory status (in the kidney), tissue damage, and vascular remodeling (in the liver and aorta) were evaluated. Cs-AqC4 was also tested in vitro on HMEC-1 cells stimulated by Ang-II to assess the involvement of Akt phosphorylation. Results: Cs-AqC4 decreased systolic and diastolic BP, reversed vascular remodeling, decreased IL-1β and TGF-β, increased IL-10, and decreased kidney and liver damage. In HMEC-1 cells, AKT phosphorylation and NO production were increased. Conclusions: Cs-AqC4 controlled inflammation and vascular remodeling, alleviating hypertension; it also improved tissue damage associated with ED, probably via Akt activation. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) have been shown to be associated with cardiac fibrosis. Atrial fibrosis is an important pathophysiological event in the progression of atrial fibrillation (AF). Although a novel circRNA calmodulin binding transcription activator 1 (circCAMTA1) has been reported to be related with the development of AF, the detailed molecular mechanisms remain largely unknown. In this study, we found that circCAMTA1 was upregulated in atrial muscle tissues of AF patients and angiotensin-II (Ang-II)-treated human atrial fibroblasts (HAFs). Moreover, circCAMTA1 expression was positively correlated with the expression of collagen (I and III) and α-SMA in atrial muscle tissues of AF patients. In vitro experiments, knockdown of circCAMTA1 significantly suppressed Ang-II-induced HAFs proliferation and reduced the expression of atrial fibrosis-associated genes, but overexpression of circCAMTA1 exhibited opposite results. In vivo experiments, circCAMTA1 knockdown ameliorated Ang-II-induced atrial fibrosis by reducing AF incidence, AF duration, and collagen synthesis. Functionally, circCAMTA1 facilitated Ang-II-induced atrial fibrosis in vitro and in vivo via downregulating the inhibitory effect of miR-214-3p on transforming growth factor β receptor 1 (TGFBR1) expression. In conclusions, circCAMTA1 knockdown alleviated atrial fibrosis through downregulating TGFBR1 expression intermediated by miR-214-3p in AF, suggesting circCAMTA1/miR-214-3p/TGFBR1 axis may be a novel therapeutic target for AF treatment in clinic. [ABSTRACT FROM AUTHOR]

Simple Summary: The placenta is a constantly changing organ that faces continuous tissue remodeling throughout gestation, reflected by recurrent stromal adaptation. The myofibroblasts, contractile stromal cells, are key players involved in orchestrating physiological tissue remodeling. Nevertheless, details regarding ultrastructural and functional aspects of myofibroblasts in the developed bovine placental stroma remain veiled. Here, the presence of myofibroblasts in the maternal placental stroma was confirmed by immunohistochemical and ultrastructural analysis, with the co-localization of several factors, e.g., α -smooth muscle actin, vimentin and nuclear progesterone receptor. During short-term tissue culture, the contraction of placentomal caruncle tissue slices was induced by angiotensin-II. Furthermore, a three-dimensional reconstruction demonstrates an example of a bovine placental myofibroblast. According to the present findings, it is postulated that the maternal stroma of the placenta in the cow contains a high proportion of contractile myofibroblastic cells. Herewith, a basis for further investigations regarding the functional aspects and the role of myofibroblasts in peri- and post-partum placental events in cattle was created. Myofibroblasts are contractile cells that exhibit features of both fibroblasts and smooth muscle cells. In the synepitheliochorial placenta of the cow myofibroblasts are found in the maternal stroma. However, a deeper understanding of the structure and function of the stromal myofibroblasts in the developed bovine placenta is still missing. Thus, immunohistochemical and ultrastructural analyses in bovine term placentomes, compared to non-pregnant caruncle samples, were conducted. To investigate functional aspects, contractility of placentomal caruncle slices was assessed in an in vitro contraction assay. Additionally, a three-dimensional reconstruction of a bovine placental myofibroblast was created. Immunofluorescent staining revealed a characteristic pattern, including cytoplasmic expression of α-smooth muscle actin, strong perinuclear signal for the intermediate filament vimentin and nuclear progesterone receptor staining. Ultrastructurally, stress fibers, extended cisternae of the rough endoplasmic reticulum and perinuclear intermediate filaments were observed. Moreover, in vitro stimulation with angiotensin-II, but not with prostaglandin F2α, induced contraction of placental caruncle tissue. Altogether, these results indicate that progesterone-responsive myofibroblasts represent a mesenchymal phenotype that is involved in the contractile properties of bovine placental stroma. Therefore, the present findings suggest a potential involvement of myofibroblasts in post-partum events of cattle, i.e., expulsion of fetal membranes and uterine involution. [ABSTRACT FROM AUTHOR]

Background: Endothelial dysfunction (ED) is a marker of vascular damage and a precursor of cardiovascular diseases such as hypertension, which involve inflammation and organ damage. Nitric oxide (NO), produced by eNOS, which is induced by pAKT, plays a crucial role in the function of a healthy endothelium. Methods: A combination of subfractions SF1 and SF3 (C4) of the aqueous fraction from Cucumis sativus (Cs-Aq) was evaluated to control endothelial dysfunction in vivo and on HMEC-1 cells to assess the involvement of pAkt in vitro. C57BL/6J mice were injected daily with angiotensin II (Ang-II) for 10 weeks. Once hypertension was established, either Cs-AqC4 or losartan was orally administered along with Ang-II for a further 10 weeks. Blood pressure (BP) was measured at weeks 0, 5, 10, 15, and 20. In addition, serum creatinine, inflammatory status (in the kidney), tissue damage, and vascular remodeling (in the liver and aorta) were evaluated. Cs-AqC4 was also tested in vitro on HMEC-1 cells stimulated by Ang-II to assess the involvement of Akt phosphorylation. Results: Cs-AqC4 decreased systolic and diastolic BP, reversed vascular remodeling, decreased IL-1β and TGF-β, increased IL-10, and decreased kidney and liver damage. In HMEC-1 cells, AKT phosphorylation and NO production were increased. Conclusions: Cs-AqC4 controlled inflammation and vascular remodeling, alleviating hypertension; it also improved tissue damage associated with ED, probably via Akt activation.

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.

AimsCurrently, no acute heart failure (AHF) therapy definitively improves outcomes. Reducing morbidity and mortality from acute heart failure (AHF) remains an unmet need. TRV027 is a novel 'biased' ligand of the angiotensin II type 1 receptor (AT1R), selectively antagonizing the negative effects of angiotensin II, while preserving the potential pro-contractility effects of AT1R stimulation. BLAST-AHF was designed to determine the safety, efficacy, and optimal dose of TRV027 to advance into future studies.Methods and resultsBLAST-AHF was a multi-centre, international, randomized, double-blind, placebo-controlled, parallel group, phase IIb dose-ranging study, enrolling patients with AHF into 4 groups: placebo, 1, 5, or 25 mg/h of TRV027. Treatment was by IV infusion for 48-96 h. The primary composite endpoint was comprised of the following: (i) time from baseline to death through day 30, (ii) time from baseline to heart failure re-hospitalization through day 30, (iii) the first assessment time point following worsening heart failure through day 5, (iv) change in dyspnea visual analogue scale (VAS) score calculated as the area under the curve (AUC) representing the change from baseline over time from baseline through day 5, and (v) length of initial hospital stay (in days) from baseline. Analyses were by modified intention-to-treat. Overall, 621 patients were enrolled. After 254 patients, a pre-specified interim analysis resulted in several protocol changes, including a lower blood pressure inclusion criterion as well as a new allocation scheme of 2:1:2:1, overweighting both placebo, and the 5 mg/h dose. TRV027 did not confer any benefit over placebo at any dose with regards to the primary composite endpoint or any of the individual components. There were no significant safety issues with TRV027.ConclusionIn this phase IIb dose-ranging AHF study, TRV027 did not improve clinical status through 30-day follow-up compared with placebo.

Background: The aim of the study was to investigate the effect of hydroalcoholic seed extract of Securigera securidaca (S. securidaca) (HESS) on liver local reninangiotensin system (RAS) in streptozotocin-induced diabetic rats. Methods: Three groups of diabetic male Wistar rats were treated with different doses of HESS (100, 200, 400 mg/Kg-BW), and the results were compared with diabetic and healthy control groups. To test the effects of HESS on liver local RAS as well as its alternative pathway, the tissue levels of renin, angiotensin-converting enzyme (ACE), ACE2, angiotensin-II (Ang-II), and Ang- (1-7) were measured. The oxidative state of liver tissue was evaluated by biomarkers of malondialdehyde (MDA), total oxidant status (TOS), and total antioxidant status (TAS). Due to the association between local RAS activity and tissue inflammation, the production of interleukins (IL) IL-1, IL-6, tumor necrosis factor alfa (TNF-a), and IL-10 in the liver was assayed in the experimental group. Results: Dose-dependent effects of HESS showed that the highest dose of the extract had a reducing effect on the hepatic levels of local RAS components including angiotensinogen, ACE, and Ang-II. Surprisingly, despite the decrease in tissue level of ACE2, an increase in Ang- (1-7) tissue concentration was observed. Decreased local RAS activity through treatment with the highest dose of HESS was associated with decreased tissue levels of proinflammatory cytokines (IL-1, IL-6, TNF-a), and increased anti-inflammatory cytokine (IL-10). Most of the effects of the extract are attributed to its antioxidant properties. Conclusions: S. securidaca seed can be suggested as a suitable drug supplement to prevent hepatic complications of diabetes. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the long-term antihypertensive action of soluble epoxide hydrolase inhibition (sEH) in angiotensin-II (AngII)-dependent hypertension might be mediated by the suppression of intrarenal AngII levels. To test this hypothesis, we examined the effects of acute (2 days) and chronic (14 days) sEH inhibition on blood pressure (BP) in transgenic rats with inducible AngII-dependent hypertension. AngII-dependent malignant hypertension was induced by 10 days' dietary administration of indole-3-carbinol (I3C), a natural xenobiotic that activates the mouse renin gene in Cyp1a1-Ren-2 transgenic rats. BP was monitored by radiotelemetry. Acute and chronic sEH inhibition was achieved using cis-4-(4-(3-adamantan-1-yl-ureido)cyclohexyloxy) benzoic acid, given at doses of 0.3, 3, 13, 26, 60 and 130 mg/L in drinking water. At the end of experiments, renal concentrations of epoxyeicosatrienoic acids, their inactive metabolites dihydroxyeicosatrienoic acids and AngII were measured. Acute BP-lowering effects of sEH inhibition in I3C-induced rats was associated with a marked increase in renal epoxyeicosatrienoic acids to dihydroxyeicosatrienoic acids ratio and acute natriuresis. Chronic treatment with cis-4-(4-(3-adamantan-1-yl-ureido)cyclohexyloxy) benzoic acid in I3C-induced rats elicited dose-dependent persistent BP lowering associated with a significant reduction of plasma and kidney AngII levels. Our findings show that the acute BP-lowering effect of sEH inhibition in I3C-induced Cyp1a1-Ren-2 transgenic rats is mediated by a substantial increase in intrarenal epoxyeicosatrienoic acids and their natriuretic action without altering intrarenal renin-angiotensin system activity. Long-term antihypertensive action of cis-4-(4-(3-adamantan-1-yl-ureido)cyclohexyloxy) benzoic acid in I3C-induced Cyp1a1-Ren-2 transgenic rats is mediated mostly by suppression of intrarenal AngII concentration.

Fibrosis serves a critical role in driving atrial remodelling‐mediated atrial fibrillation (AF). Abnormal levels of the transcription factor PU.1, a key regulator of fibrosis, are associated with cardiac injury and dysfunction following acute viral myocarditis. However, the role of PU.1 in atrial fibrosis and vulnerability to AF remain unclear. Here, an in vivo atrial fibrosis model was developed by the continuous infusion of C57 mice with subcutaneous Ang‐II, while the in vitro model comprised atrial fibroblasts that were isolated and cultured. The expression of PU.1 was significantly up‐regulated in the Ang‐II‐induced group compared with the sham/control group in vivo and in vitro. Moreover, protein expression along the TGF‐β1/Smads pathway and the proliferation and differentiation of atrial fibroblasts induced by Ang‐II were significantly higher in the Ang‐II‐induced group than in the sham/control group. These effects were attenuated by exposure to DB1976, a PU.1 inhibitor, both in vivo and in vitro. Importantly, in vitro treatment with small interfering RNA against Smad3 (key protein of TGF‐β1/Smads signalling pathway) diminished these Ang‐II‐mediated effects, and the si‐Smad3‐mediated effects were, in turn, antagonized by the addition of a PU.1‐overexpression adenoviral vector. Finally, PU.1 inhibition reduced the atrial fibrosis induced by Ang‐II and attenuated vulnerability to AF, at least in part through the TGF‐β1/Smads pathway. Overall, the study implicates PU.1 as a potential therapeutic target to inhibit Ang‐II‐induced atrial fibrosis and vulnerability to AF. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrosis serves as a disease initiating mechanism in the development of atrial fibrillation. Angiotensin II (Ang-II), a key mediator for atrial fibrosis, aberrantly activates atrial fibroblasts (AFs) into myofibroblasts, resulting in subsequent excessive synthesis and deposition of extracellular matrix (ECM). Cadherin-11 (CDH11) is essential in the development of non-cardiac fibrotic diseases. In this study, we investigated its role in the pathogenesis and underlying mechanism of atrial fibrillation. Methods: We obtained left atrial tissues from either patients with atrial fibrillation or Ang-II-induced atrial fibrosis mice. We utilized a global CDH11 knockout mouse (CDH11−/-) model to determine the effect of CDH11 on AF cell proliferation, migration, ECM synthesis/deposition. RNA-Seq of isolated AFs from CDH11−/- or normal mice was performed and differential expressed genes were analyzed. The mouse susceptibility to atrial fibrillation was examined by cardiac electrophysiology. Results: We found that cadherin-11 was significantly up-regulated in fibrotic atrial tissue from patients with atrial fibrillation and Ang-II-induced mice. Both normal and CDH11−/- mice did not develop atrial fibrosis at resting state. However, after Ang-II infusion, unlike severe atrial fibrosis occurred in normal mice, CDH11−/- mice displayed a reduced atrial fibrosis. Atrial fibroblasts with CDH11 deletion from CDH11−/- mice showed reduction in Ang-II-induced cell proliferation, migration and ECM synthesis/deposition, indicating the involvement of CDH11 in atrial fibrosis. Consistently, RNA-Seq of CDH11-null AFs uncovered significant decrease in pro-fibrotic gene expression. In addition, we identified reduction of transcripts associated with Smad2/3, ERK1/2 and JNK pathways. Further, CDH11−/- mice showed a significantly attenuated Ang-II-induced susceptibility to atrial fibrillation. Conclusion: Our results indicate that CDH11 potentiates Ang-II-induced activation of AFs. The pathogenesis of atrial fibrosis is through CDH11 mediated stimulation of Smad2/3, ERK1/2 and JNK pathways. Thus, CDH11 might serve as a novel therapeutic target for ameliorating the development of atrial fibrillation. [ABSTRACT FROM AUTHOR]

Abstract Background Spaceflight or microgravity conditions cause myocardial atrophy and dysfunction, contributing to post-flight orthostatic intolerance. However, the underlying mechanisms remain incompletely understood and preventive approaches are limited. This study investigated whether and how losartan, a blocker of angiotensin-II receptor, preserved cardiomyocyte size and prevented myocardial dysfunction during microgravity. Method Adult male mice were suspended with their tails to simulate microgravity. Echocardiography was performed to assess myocardial function. Heart weight and cardiomyocyte size were measured. NADPH oxidase activation was determined by analyzing membrane translocation of its cytosolic subunits including p47 phox , p67 phox and Rac1. Heart tissues were also assayed for oxidative stress, p47 phox phosphorylation (Ser345), MuRF1 protein levels and angiotensin-II production. Results Tail-suspension for 28 days increased angiotensin-II production in hearts, decreased cardiomyocyte size and heart weight, and induced myocardial dysfunction. Administration of losartan preserved cardiomyocyte size and heart weight, and prevented myocardial dysfunction in tail-suspended mice. These cardioprotective effects of losartan were associated with inhibition of p47 phox phosphorylation (Ser345), NADPH oxidase and oxidative stress in tail-suspended mouse hearts. Additionally, the NADPH oxidase inhibitor, apocynin, also reduced oxidative stress, preserved cardiomyocyte size and heart weight, and improved myocardial function in tail-suspended mice. Furthermore, losartan but not apocynin attenuated tail-suspension-induced up-regulation of MuRF1 protein in mouse hearts. Conclusions Administration of losartan preserves cardiomyocyte size and prevents myocardial dysfunction under microgravity by blocking p47 phox phosphorylation and NADPH oxidase activation, and by inhibiting MuRF1 expression. Thus, losartan may be a useful drug to prevent microgravity-induced myocardial abnormalities.

Human infection by the SARS-CoV-2 is causing the current COVID-19 pandemic. With the growing numbers of cases and deaths, there is an urgent need to explore pathophysiological hypotheses in an attempt to better understand the factors determining the course of the disease. Here, we hypothesize that COVID-19 severity and its symptoms could be related to transmembrane and soluble Angiotensin-converting enzyme 2 (tACE2 and sACE2); Angiotensin II (ANG II); Angiotensin 1-7 (ANG 1-7) and angiotensin receptor 1 (AT1R) activation levels. Additionally, we hypothesize that an early peak in ANG II and ADAM-17 might represent a physiological attempt to reduce viral infection via tACE2. This viewpoint presents: (1) a brief introduction regarding the renin-angiotensin-aldosterone system (RAAS), detailing its receptors, molecular synthesis, and degradation routes; (2) a description of the proposed early changes in the RAAS in response to SARS-CoV-2 infection, including biological scenarios for the best and worst prognoses; and (3) the physiological pathways and reasoning for changes in the RAAS following SARS-CoV-2 infection.

In patients with chronic myeloid leukemia (CML) in chronic phase who have achieved complete molecular remission on imatinib therapy, clinical trials from France and Australia have demonstrated that the majority experience prompt molecular relapse of their leukemia upon discontinuation of the drug, showing that long-term monotherapy with tyrosine kinase inhibitors is not curative in the majority of patients with CML. This has focused attention on strategies to eradicate residual disease in CML that is presumed to arise from malignant Ph+ stem cells, which should result in permanent cure and long-term leukemia-free survival. Here, we review the evidence that targeting CML stem cells will be of clinical benefit and discuss pharmacological and immunological approaches to accomplish this goal. Where possible, we link preclinical studies of CML stem cell biology to emerging results from clinical trials of agents that may target these cells.

Human infection by the SARS-CoV-2 is causing the current COVID-19 pandemic. With the growing numbers of cases and deaths, there is an urgent need to explore pathophysiological hypotheses in an attempt to better understand the factors determining the course of the disease. Here, we hypothesize that COVID-19 severity and its symptoms could be related to transmembrane and soluble Angiotensin-converting enzyme 2 (tACE2 and sACE2); Angiotensin II (ANG II); Angiotensin 1-7 (ANG 1-7) and angiotensin receptor 1 (AT1R) activation levels. Additionally, we hypothesize that an early peak in ANG II and ADAM-17 might represent a physiological attempt to reduce viral infection via tACE2. This viewpoint presents: (1) a brief introduction regarding the renin-angiotensin-aldosterone system (RAAS), detailing its receptors, molecular synthesis, and degradation routes; (2) a description of the proposed early changes in the RAAS in response to SARS-CoV-2 infection, including biological scenarios for the best and worst prognoses; and (3) the physiological pathways and reasoning for changes in the RAAS following SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

Previously, we showed vascular endothelial overexpression of human-CYP2J2 enhances coronary reactive hyperemia in Tie2-CYP2J2 Tr mice, and eNOS−/− mice had overexpression of CYP2J-epoxygenase with adenosine A2A receptor-induced enhance relaxation, but we did not see the response in CYP2J-epoxygenase knockout mice. Therefore, we hypothesized that Cyp2j5-gene deletion affects acetylcholine- and 5'-N-ethylcarboxamidoadenosine (NECA) (adenosine)-induced relaxation and their response is partially inhibited by angiotensin-II (Ang-II) in mice. Acetylcholine (Ach)-induced response was tested with N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH, CYP-epoxygenase inhibitor; 10−5M) and Ang-II (10−6M). In Cyp2j5−/− mice, ACh-induced relaxation was different from C57Bl/6 mice, at 10−5 M (76.1 ± 3.3 vs. 58.3 ± 5.2, P < 0.05). However, ACh-induced relaxation was not blocked by MS-PPOH in Cyp2j5−/−: 58.5 ± 5.0%, P > 0.05, but blocked in C57Bl/6: 52.3 ± 7.5%, P < 0.05, and Ang-II reduces ACh-induced relaxation in both Cyp2j5−/− and C57Bl/6 mice (38.8 ± 3.9% and 45.9 ± 7.8, P 0.05). However, NECA-induced response was reduced by Ang-II in both Cyp2j5−/− and C57Bl/6 mice (−10.8 ± 2.3% and 3.2 ± 2.7, P < 0.05). Data suggest that ACh-induced relaxation in Cyp2j5−/− mice depends on nitric oxide (NO) but not CYP-epoxygenases, and the NECA-induced different response in male vs. female Cyp2j5−/− mice when Ang-II treated.

Background/Aims: Chronic heart failure (HF) disrupts normal kidney function and leads to cardiorenal syndrome that further promotes HF progression. To identify potential participants in HF-related injury, we analyzed kidney proteome in an established HF model. Methods: HF was induced by chronic volume overload in male HanSD rats using aorto-caval fistula. After 21 weeks, cardiac and renal functions (in-situ kidney study) and renal proteomics were studied in sham-operated (controls) and HF rats, using iTRAQ labeling and LC-MS with Orbitrap Fusion, leading to identification and quantification of almost 4000 proteins. Results: Compared to controls, HF rats had cardiac hypertrophy, systemic and pulmonary congestion. Kidneys of HF rats had reduced renal blood flow, sodium excretion and urine production. While glomerular filtration rate, serum cystatin C and creatinine were still normal compared to controls, HF kidneys showed albuminuria and markedly increased tissue angiotensin-II levels (5-fold). HF kidneys (versus controls) displayed differential expression (˃1.5-fold) of 67 proteins. The most upregulated were angiotensin-converting enzyme (ACE, ˃20-fold), advanced glycosylation product-specific receptor (RAGE, 14-fold), periostin (6.8-fold), caveolin-1 (4.5-fold) and other proteins implicated in endothelial function (vWF, cavins 1-3, T-kininogen 2), proinflammatory ECM activation (MFAP4, collagen-VI, galectin-3, FHL-1, calponin) and proteins involved in glomerular filtration membrane integrity (CLIC5, ZO-1). Carboxylesterase-1D (CES1D), an enzyme that converts ACE inhibitors or sacubitril into active drugs, was also upregulated in HF kidneys. Conclusion: Chronic HF leads to latent kidney injury, associated with deep changes in kidney protein composition. These alterations may act in concert with intrarenal renin-angiotensin system activation and may serve as markers and/or targets to tackle cardiorenal syndrome.

Previously, we showed vascular endothelial overexpression of human-CYP2J2 enhances coronary reactive hyperemia in Tie2-CYP2J2 Tr mice, and eNOS−/− mice had overexpression of CYP2J-epoxygenase with adenosine A2A receptor-induced enhance relaxation, but we did not see the response in CYP2J-epoxygenase knockout mice. Therefore, we hypothesized that Cyp2j5 -gene deletion affects acetylcholine- and 5'-N-ethylcarboxamidoadenosine (NECA) (adenosine)-induced relaxation and their response is partially inhibited by angiotensin-II (Ang-II) in mice. Acetylcholine (Ach)-induced response was tested with N -(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH, CYP-epoxygenase inhibitor; 10−5M) and Ang-II (10−6M). In Cyp2j5−/− mice, ACh-induced relaxation was different from C57Bl/6 mice, at 10−5 M (76.1 ± 3.3 vs. 58.3 ± 5.2, P < 0.05). However, ACh-induced relaxation was not blocked by MS-PPOH in Cyp2j5−/− : 58.5 ± 5.0%, P > 0.05, but blocked in C57Bl/6: 52.3 ± 7.5%, P < 0.05, and Ang-II reduces ACh-induced relaxation in both Cyp2j5−/− and C57Bl/6 mice (38.8 ± 3.9% and 45.9 ± 7.8, P < 0.05). In addition, NECA-induced response was tested with Ang-II. In Cyp2j5−/− mice, NECA-induced response was not different from C57Bl/6 mice at 10−5M (23.1 ± 2.1 vs. 21.1 ± 3.8, P > 0.05). However, NECA-induced response was reduced by Ang-II in both Cyp2j5−/− and C57Bl/6 mice (−10.8 ± 2.3% and 3.2 ± 2.7, P < 0.05). Data suggest that ACh-induced relaxation in Cyp2j5−/− mice depends on nitric oxide (NO) but not CYP-epoxygenases, and the NECA-induced different response in male vs. female Cyp2j5−/− mice when Ang-II treated. [ABSTRACT FROM AUTHOR]

Aim. To investigate the plasma concentrations of cytokines and vasoactive molecules in patients with coronary heart disease (CHD) in the presence of hypertension in relation to the angiotensin-converting-enzyme (ACE) inhibitor level reflecting the degree of renin-angiotensin-aldosterone system (RAAS) inhibition. Subjects and methods. 72 patients with NYHA functional class (FC) II-III angina pectoris and 40 healthy persons at the age of 47-65 years were examined in a controlled cohort study. Enzyme immunoassay was employed to determine the serum concentrations of interleukins (IL) (IL-2, IL-12, IL-17A, and IL-24), the vasoactive molecules of bradykinin, serotonin, ACE, angiotensin-II (AT-II), NO, and endothelin-1 (ET-1), and plasma renin activity. In addition, the plasma level of the tetrapeptide N-acetyl-Ser-Asp-Lys-Pro was used as a marker for ACE inhibition. Results. The patients with CHD occurring in the presence of hypertension compared with the apparently healthy individuals displayed decreased ET-1 and NO production along with elevated levels of serotonin, AT-II, as well as IL-17A and IL-12. The found changes were accompanied by reduced renin activity. Thus, the individuals with low ACE inhibitor levels showed more pronounced production of the proinflammatory cytokine IL-17A, as well as high plasma concentrations of ACE and NO. The high ACE inhibitor level that reflects patient adherence to appropriate antihypertensive therapy is associated with the reduced production of IL-2 and with the minimum serum levels of ACE, AT-II, and NO, being characterized by the high production of IL-12 and serotonin at the same time. Conclusion. In patients with CHD and hypertension, the high plasma enzyme inhibitor concentration that reflects the activity of appropriate antihypertensive therapy, by contributing to the strengthening of the mechanisms of relaxation of blood vessels, is associated with the risk for proinflammatory activation of whole blood cells and platelets. The mean ACE inhibitor levels that reflect moderate RAAS suppression and are characterized by a relatively low proinflammatory activation of mononuclear cells may be more preferable than the maximum ones, from the point of view of slowing the progression of the subclinical inflammatory process of the vascular wall and preventing possible CHD exacerbations. This determines the feasibility of estimating the plasma level of an ACE inhibitor to control the depth of inhibition of RAAS activity.

Background/Aims: Renal injuries induced by increased intra-glomerular pressure coincide with podocyte detachment from the glomerular basement membrane (GBM). In previous studies, it was demonstrated that mesangial cells have a crucial role in the pathogenesis of malignant hypertension. However, the exact pathophysiological cascade responsible for podocyte detachment and its relationship with mesangial cells has not been fully elucidated yet and this was the aim of the current study. Methods: Rat renal mesangial or podocytes were exposed to high hydrostatic pressure in an in-vitro model of malignant hypertension. The resulted effects on podocyte detachment, apoptosis and expression of podocin and integrinβ1 in addition to Angiotensin-II and TGF-β1 generation were evaluated. To simulate the paracrine effect podocytes were placed in mesangial cell media pre-exposed to pressure, or in media enriched with Angiotensin-II, TGF-β1 or receptor blockers. Results: High pressure resulted in increased Angiotensin-II levels in mesangial and podocyte cells. Angiotensin-II via the AT1 receptors reduced podocin expression and integrinβ1, culminating in detachment of both viable and apoptotic podocytes. Mesangial cells exposed to pressure had a greater increase in Angiotensin-II than pressure-exposed podocytes. The massively increased concentration of Angiotensin-II by mesangial cells, together with increased TGF-β1 production, resulted in increased apoptosis and detachment of non-viable apoptotic podocytes. Unlike the direct effect of pressure on podocytes, the mesangial mediated effects were not related to changes in adhesion proteins expression. Conclusions: Hypertension induces podocyte detachment by autocrine and paracrine effects. In a direct response to pressure, podocytes increase Angiotensin-II levels. This leads, via AT1 receptors, to structural changes in adhesion proteins, culminating in viable podocyte detachment. Paracrine effects of hypertension, mediated by mesangial cells, lead to higher levels of both Angiotensin-II and TGF-β1, culminating in apoptosis and detachment of non-viable podocytes.

Background: In healthy pregnancies, components of the Renin-Angiotensin system (RAS) are present in the placental villi and contribute to invasion, migration, and angiogenesis. At the same time, soluble fms-like tyrosine kinase 1 (sFlt-1) production is induced after binding of ANG-II to its receptor (AT-1R) in response to hypoxia. As RAS plays an essential role in the pathogenesis of COVID-19, we hypothesized that angiogenic marker (sFlt-1) and RAS components (ANG-II and ACE-2) may be related to adverse outcomes in pregnant women with COVID-19; Methods: Prospective cohort study. Primary outcome was severe pneumonia. Secondary outcomes were ICU admission, intubation, sepsis, and death. Spearman’s Rho test was used to analyze the correlation between sFlt-1 and ANG-II levels. The sFlt-1/ANG-II ratio was determined and the association with each adverse outcome was explored by logistic regression analysis and the prediction was assessed using receiver-operating-curve (ROC); Results: Among 80 pregnant women with COVID-19, the sFlt-1/ANG-II ratio was associated with an increased probability of severe pneumonia (odds ratio [OR]: 1.31; p = 0.003), ICU admission (OR: 1.05; p = 0.007); intubation (OR: 1.09; p = 0.008); sepsis (OR: 1.04; p = 0.008); and death (OR: 1.04; p = 0.018); Conclusion: sFlt-1/ANG-II ratio is a good predictor of adverse events such as pneumonia, ICU admission, intubation, sepsis, and death in pregnant women with COVID-19.

Mesenchymal stem cells (MSCs) pretreatment is an effective route for improving cell-based therapy of endothelial cell survival, vascular stabilization, and angiogenesis. We hypothesized that the application of human umbilical cord-MSCs (hUC-MSCs) pretreated with angiotensin-II (Ang-II) might be a potential therapeutic approach for severe acute pancreatitis (SAP). Therefore, the effect of Ang-II pretreated hUC-MSCs on SAP was investigated in vitro and in vivo. Methods: In the present study, human umbilical cord-derived MSCs pretreated with or without Ang-II were delivered through the tail vein of rats 12 h after induction of SAP. Pancreatitis severity scores and serum lipase levels, as well as the levels of VEGF and VEGFR2 were evaluated. Results: We found that the administration of Ang-II-MSCs significantly inhibited pancreatic injury, as reflected by reductions of pancreatitis severity scores, serum amylase and serum lipase levels. Furthermore, the reduced apoptotic rate and increased tube formation in human umbilical vein endothelial Cells (HUVEC) were found resulting from the administration of Ang-II-MSC-CM. Moreover, knockdown of VEGFR2 can block the effect of Ang-II-MSC-CM on preventing HUVEC from apoptosis, as well as the capacity of tube formation was also suppressed. In addition, the expression of increased Bcl-2 and alleviated caspase-3 were observed in HUVEC and HUVEC transfectants exposure to Ang-II-MSC-CM. Conclusion: Collectively, these results elucidated that the pretreatment of hUC-MSCs with Ang-II improved the outcome of MSC-based therapy for SAP via enhancing angiogenesis and ameliorating endothelial cell dysfunction in a VEGFR2 dependent manner.

Astaxanthin (ASX) is a natural antioxidant with preventive and therapeutic effects on various human diseases. However, the role of ASX in cardiac hypertrophy and its underlying molecular mechanisms remain unclear.Cardiomyocytes (AC16) were used with angiotensin-II (Ang-II) to mimic the cardiac hypertrophy cell model. The protein levels of hypertrophy genes, GATA4, and methyltransferase-like 3 (METTL3) were determined by western blot analysis. Cell size was assessed using immunofluorescence staining. The expression of circ&#95;0078450, miR-338-3p, and GATA4 were analyzed by quantitative real-time PCR. Also, the interaction between miR-338-3p and circ&#95;0078450 or GATA4 was confirmed by dual-luciferase reporter and RIP assays, and the regulation of METTL3 on circ&#95;0078450 was verified by MeRIP and RIP assays.ASX reduced the hypertrophy gene protein expression and cell size in Ang-II-induced AC16 cells. Circ&#95;0078450 was promoted under Ang-II treatment, and ASX reduced circ&#95;0078450 expression in Ang-II-induced AC16 cells. Circ&#95;0078450 could sponge miR-338-3p to positively regulate GATA4 expression, and GATA4 overexpression overturned the suppressive effect of circ&#95;0078450 knockdown on Ang-II-induced cardiomyocyte hypertrophy. Also, the inhibitory effect of ASX on Ang-II-induced cardiomyocyte hypertrophy could be reversed by circ&#95;0078450 or GATA4 overexpression. In addition, METTL3 mediated the m6A methylation of circ&#95;0078450 to enhance circ&#95;0078450 expression. Moreover, METTL3 knockdown suppressed Ang-II-induced cardiomyocyte hypertrophy by inhibiting circ&#95;0078450 expression.Our data showed that ASX repressed cardiac hypertrophy by regulating the METTL3/circ&#95;0078450/miR-338-3p/GATA4 axis.

Molecular targeted therapy with lenvatinib is commonly offered to advanced hepatocellular carcinoma (HCC) patients, although it is often interrupted by adverse effects which require a reduction in the initial dose. Thus, an alternative lenvatinib-based therapy to compensate for dose reduction is anticipated. This study aimed to assess the effect of combination of low-dose of lenvatinib and the angiotensin-II (AT-II) receptor blocker losartan on human HCC cell growth. In vitro studies found that losartan suppressed the proliferation by inducing G1 arrest and caused apoptosis as indicated by the cleavage of caspase-3 in AT-II-stimulated HCC cell lines (Huh-7, HLE, and JHH-6). Losartan attenuated the AT-II-stimulated production of vascular endothelial growth factor-A (VEGF-A) and interleukin-8 and suppressed lenvatinib-mediated autocrine VEGF-A production in HCC cells. Moreover, it directly inhibited VEGF-mediated endothelial cell growth. Notably, the combination of lenvatinib and losartan augmented the cytostatic and angiostatic effects of the former at a low-dose, reaching those achieved with a conventional dose. Correspondingly, a HCC tumor xenograft assay showed that the oral administration of losartan combined with lenvatinib reduced the subcutaneous tumor burden and intratumor vascularization in BALB/c nude mice. These findings support that this regimen could be a viable option for patients intolerant to standard lenvatinib dosage.

Nω-nitro-l-arginine methyl ester (L-NAME) is a non-specific nitric oxide (NO) synthase inhibitor, commonly used for the induction of NO-deficient hypertension. The objective of the present study was to investigate the effects of chrysin with flavnoids, on L-NAME-induced hypertensive rats. Methods: An experimental hypertensive animal (180–220 g) model was induced by L-NAME intake on rats. In treatment chrysin was orally administered 25 mg/kg body weight (b.w.). Blood pressure was measured by tail cuff plethysmography system. Cardiac and vascular function was evaluated by Langendorff isolated heart system with Angiotensin II (Ang-II), Hexo oxygenase (HO-1), cyclic guanosine monophosphate (cGMP) concentration in tissues respectively. Rats with hypertension showed an elevated blood pressure (BP), left ventricular functions, ang II, and decreased cGMP concentration of tissues. Treatment of chrysin is reverse to near normal in left ventricular functions, Ang-II, Ho-1 and decreased cGMP concentration of tissues. The antihypertensive effect of chrysin appears to be mediated by a reduction in left ventricular functions, cardiac oxidative stress and Ang-II, an increase in cardiac HO-1, cGMP concentration and a prevention of plasma nitric oxide loss. [ABSTRACT FROM AUTHOR]

Background: Fisetin, a polyphenolic compound, has drawn notable attention owing to its antioxidant, anti-inflammatory, anti-cancer and neuroprotective effects. However, the cardiac effects of fisetin are not clear yet.Hypothesis: The aim of the present study is to examine the cardioprotective effect of fisetin against Ang-II induced apoptosis in H9c2 cells and in spontaneous hypertensive rats (SHR).Methods/study Design: The in vitro protective effect of fisetin was evaluated after the cells were treated with fisetin (50 µM/ml/ 24  h) for 2  h prior or after Ang-II administration to induce apoptosis. For in vivo experiments, SHRs were orally administered with fisetin (10  mg/kg) twice a week for 6 weeks. Cellular apoptosis was analyzed by TUNEL staining assay and the modulation in the expression levels of proteins involved in apoptosis and cell survival were determined by western blotting.Results: Our results demonstrate the potent cardioprotective efficacy of fisetin against Ang-II induced apoptosis in H9c2 cells and in SHR models. Fisetin administration reduced the apoptotic nuclei considerably And reduced the expression of apoptotic proteins such as TNF- α, Fas L, FADD, Cleaved caspase-3 and Cleaved PARP and increased the cell survival and anti-apoptotic proteins like Bcl-2, Bcl-xL, p-IGF1R, p-PI3K and p-AKT in both in vitro and in vivo models.Conclusion: In conclusion, the results of the present study reveal that fisetin activates the IGF-IR-dependent p-PI3K/p-Akt survival signaling pathway and suppresses the caspase dependent apoptosis. [ABSTRACT FROM AUTHOR]

Background and Objectives: Activation of AT1 receptor (type 1 angiotensin II receptor) has an important role in the pathogenesis of renal ischemia-reperfusion injuries. In the present study, the effect of losartan on the level of reactive nitrogen species (RNS) and renal function in renal ischemia-reperfusion injuries, was assessed in rat. Methods: Eighteen male Wistar rats were randomly divided into three groups of sham, control ischemic, and ischemic treated. Ischemia was induced by occlusion of renal arteries for 60 min. Losartan (10mg/kg) were injected intraperitoneally one hour before ischemia, and also 24, 48, and 72 hours after ischemia. Blood samples were collected for measuring creatinine before and 72 hours after ischemia. Finally, NOx concentration and histopathological changes were assessed 72 hours after ischemia. Results: The mean of creatinine concentration in the animals in sham and control ischemic groups at the beginning of experiment were 0.37±0.21 and 0.27±0.14mg/dl, respectively. Induction of ischemia significantly increased creatinine concentration (2.75±2.26mg/dl) in the control ischemic group (p=0.020). The NOx concentration significantly increased in control ischemic group (29.49±5.93nmol/mg protein) compared to sham group (1.00±0.23nmol/mg protein), (p>0.001). Losartan significantly decreased the concentration of creatinine (0.68±0.52mg/dl) in the ischemic treated group (p=0.044), and considerably decreased the NOx level in ischemic treated animals along with histhopathological altrations (53%). Conclusion: The use of losartan can effectively prevent renal ischemia-reperfusion injuries through reduction of RNS and improve the function of the ischemic kidney.

Background Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are the most commonly prescribed antihypertensive medications in higher-risk surgical patients. However, there is no clinical consensus on their use in the perioperative period, in part, due to an inconsistent evidence-base. To help inform the design of a large multi-centre randomized controlled trial (ISRCTN17251494), we undertook a questionnaire-based survey exploring variability in ACEi/ARB prescribing in perioperative practice. Methods The online survey included perioperative scenarios to examine how consistent respondents were with their stated routine preoperative practice. Clinicians with an academic interest in perioperative medicine were primarily targeted between July and September 2017. STROBE guidelines for observational research and ANZCA Trials Group Survey Reporting recommendations were adhered to. Results 194 responses were received, primarily from clinicians practicing in the UK. A similar minority of respondents continue ACEi (n = 57; 30%) and ARBs (n = 62; 32%) throughout the perioperative period. However, timing of preoperative cessation was highly variable, and rarely influenced by the pharmacokinetics of individual ACE-i/ARBs. Respondents’ stated routine practice was frequently misaligned with their management of common pre- and postoperative scenarios involving continuation or restarting ACE-i/ARBs. Discussion This survey highlights many inconsistencies amongst clinicians’ practice in perioperative ACE-i/ARB management. Studies designed to reveal an enhanced understanding of perioperative mechanisms at play, coupled with randomised controlled trials, are required to rationally inform the clinical management of ACE-i/ARBs in patients most at risk of postoperative morbidity.

The phylogenetic theory of general pathology postulates an inversion of the concept about the role of arterial blood pressure (AP) in physiology and pathology. Activation of the synthesis of the renin → angiotensin-II (AG-II) system components by nephron and increase in aldosterone secretion are not aimed at elevating AP., but at maintaining the volume of extracellular medium, part of the Third Word Ocean where all cells still live as millions of years ago. Phylogenetically early internal organs cannot regulate the effects of phylogenetically late AP., a physical factor of metabolism. AP is not increased by kidneys, but by the vasomotor center that attempts to reanimate nephronal function, the biological function of endoecology and biological reaction of excretion by increasing AP in proximal and, subsequently, hydrodynamic pressure in the distal region of arterial bed. In addition to the major role in the realization of the biological function of locomotion, AP is a physical factor involved in compensation of impaired functions of homeostasis, trophology, endoecology and adaptation. Levels of metabolism regulation have developed during phylogenesis. Biochemical reactions are specifically regulated at the autocrine level. In paracrine-regulated cell communities of distal arterial bed, metabolism is regulated by millions of local peristaltic pumps by compensating the biological reactions of endothelium-dependent vasodilation, microcirculation, effects of humoral messengers and hormones. In vivo metabolism is regulated nonspecifically from the vasomotor center level by a physical factor (AP) by sympathetic activation of the heart; AP in proximal and distal regions of arterial bed overcomes peripheral resistance and «squeezes through» the arterioles where microcirculation is impaired. AG-II acts as a vasoconstrictor only in the distal arterial bed. In essential (metabolic) arterial hypertension, paracrine cell communities of nephrons and kidneys are involved in realization of pathologic compensation in the second turn and often “suffer being innocent” , similar to other “target” organs”, such as brain, lungs and heart.

Background/Aims: Chronic heart failure (HF) disrupts normal kidney function and leads to cardiorenal syndrome that further promotes HF progression. To identify potential participants in HF-related injury, we analyzed kidney proteome in an established HF model. Methods: HF was induced by chronic volume overload in male HanSD rats using aorto-caval fistula. After 21 weeks, cardiac and renal functions (in-situ kidney study) and renal proteomics were studied in sham-operated (controls) and HF rats, using iTRAQ labeling and LC-MS with Orbitrap Fusion, leading to identification and quantification of almost 4000 proteins. Results: Compared to controls, HF rats had cardiac hypertrophy, systemic and pulmonary congestion. Kidneys of HF rats had reduced renal blood flow, sodium excretion and urine production. While glomerular filtration rate, serum cystatin C and creatinine were still normal compared to controls, HF kidneys showed albuminuria and markedly increased tissue angiotensin-II levels (5-fold). HF kidneys (versus controls) displayed differential expression (˃1.5-fold) of 67 proteins. The most upregulated were angiotensin-converting enzyme (ACE, ˃20-fold), advanced glycosylation product-specific receptor (RAGE, 14-fold), periostin (6.8-fold), caveolin-1 (4.5-fold) and other proteins implicated in endothelial function (vWF, cavins 1-3, T-kininogen 2), proinflammatory ECM activation (MFAP4, collagen-VI, galectin-3, FHL-1, calponin) and proteins involved in glomerular filtration membrane integrity (CLIC5, ZO-1). Carboxylesterase-1D (CES1D), an enzyme that converts ACE inhibitors or sacubitril into active drugs, was also upregulated in HF kidneys. Conclusion: Chronic HF leads to latent kidney injury, associated with deep changes in kidney protein composition. These alterations may act in concert with intrarenal renin-angiotensin system activation and may serve as markers and/or targets to tackle cardiorenal syndrome. [ABSTRACT FROM AUTHOR]

Background. Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are the most commonly prescribed antihypertensive medications in higher-risk surgical patients. However, there is no clinical consensus on their use in the perioperative period, in part, due to an inconsistent evidence-base. To help inform the design of a large multi-centre randomized controlled trial (ISRCTN17251494), we undertook a questionnaire-based survey exploring variability in ACEi/ARB prescribing in perioperative practice. Methods. The online survey included perioperative scenarios to examine how consistent respondents were with their stated routine preoperative practice. Clinicians with an academic interest in perioperative medicine were primarily targeted between July and September 2017. STROBE guidelines for observational research and ANZCA Trials Group Survey Reporting recommendations were adhered to. Results. 194 responses were received, primarily from clinicians practicing in the UK. A similar minority of respondents continue ACEi (n = 57; 30%) and ARBs (n = 62; 32%) throughout the perioperative period. However, timing of preoperative cessation was highly variable, and rarely influenced by the pharmacokinetics of individual ACE-i/ARBs. Respondents' stated routine practice was frequently misaligned with their management of common pre- and postoperative scenarios involving continuation or restarting ACE-i/ARBs. Discussion. This survey highlights many inconsistencies amongst clinicians' practice in perioperative ACE-i/ARB management. Studies designed to reveal an enhanced understanding of perioperative mechanisms at play, coupled with randomised controlled trials, are required to rationally inform the clinical management of ACE-i/ARBs in patients most at risk of postoperative morbidity. [ABSTRACT FROM AUTHOR]

Background/Aims: Renal injuries induced by increased intra-glomerular pressure coincide with podocyte detachment from the glomerular basement membrane (GBM). In previous studies, it was demonstrated that mesangial cells have a crucial role in the pathogenesis of malignant hypertension. However, the exact pathophysiological cascade responsible for podocyte detachment and its relationship with mesangial cells has not been fully elucidated yet and this was the aim of the current study. Methods: Rat renal mesangial or podocytes were exposed to high hydrostatic pressure in an in-vitro model of malignant hypertension. The resulted effects on podocyte detachment, apoptosis and expression of podocin and integrinβ1 in addition to Angiotensin-II and TGF-β1 generation were evaluated. To simulate the paracrine effect podocytes were placed in mesangial cell media pre-exposed to pressure, or in media enriched with Angiotensin-II, TGF-β1 or receptor blockers. Results: High pressure resulted in increased Angiotensin-II levels in mesangial and podocyte cells. Angiotensin-II via the AT1 receptors reduced podocin expression and integrinβ1, culminating in detachment of both viable and apoptotic podocytes. Mesangial cells exposed to pressure had a greater increase in Angiotensin-II than pressure-exposed podocytes. The massively increased concentration of Angiotensin-II by mesangial cells, together with increased TGF-β1 production, resulted in increased apoptosis and detachment of non-viable apoptotic podocytes. Unlike the direct effect of pressure on podocytes, the mesangial mediated effects were not related to changes in adhesion proteins expression. Conclusions: Hypertension induces podocyte detachment by autocrine and paracrine effects. In a direct response to pressure, podocytes increase Angiotensin-II levels. This leads, via AT1 receptors, to structural changes in adhesion proteins, culminating in viable podocyte detachment. Paracrine effects of hypertension, mediated by mesangial cells, lead to higher levels of both Angiotensin-II and TGF-β1, culminating in apoptosis and detachment of non-viable podocytes. [ABSTRACT FROM AUTHOR]

Introduction: Transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF) are often described as the initial pro-fibrotic mediators upregulated early in fibrosis models dependent on angiotensin II (Ang-II). In the present study, we explore the mechanistic link between TGF-β and CTGF expression by using a novel TGF-β trap. Materials and methods: NIH/3T3 fibroblasts were subjected to TGF-β with or without TGF-β trap or 1D11 antibody, CTGF or CTGF plus TGF-β for six or 24 hours, and then used for quantitative real-time polymerase chain reaction (qRT-PCR) or immunocytochemistry. Male C57BL/6 mice were infused with Ang-II and randomly assigned TGF-β trap for six or 24 hours. Hearts were harvested for histological analyses, qRT-PCR and western blotting. Results: Exogenous TGF-β-induced fibroblasts resulted in significant upregulation of CTGF, TGF-β and type I collagen transcript levels in vitro. Additionally, TGF-β promoted the differentiation of fibroblasts into α-SMA+ myofibroblasts. CTGF expression was reduced by the addition of TGF-β trap or neutralizing antibody, confirming that its expression is dependent on TGF-β signaling. In contrast, exogenous CTGF did not appear to have an effect on fibroblast production of pro-fibrotic transcripts or fibroblast differentiation. Ang-II infusion in vivo led to a significant increase in TGF-β and CTGF mRNA expression at six and 24 hours with corresponding changes in Smad2 phosphorylation (pSmad2), indicative of increased TGF-β signaling. Ang-II animals that received the TGF-β trap demonstrated reduced CTGF mRNA levels and pSmad2 at six hours, suggesting that early CTGF expression is dependent on TGF-β signaling. Conclusions: We demonstrated that CTGF expression is dependent on TGF-β signaling both in vitro and in vivo in a model of myocardial fibrosis. This also suggests that early myocardial CTGF mRNA expression (six hours) after Ang-II exposure is likely dependent on latent TGF-β activation via the canonical Smad-dependent pathway in resident cardiac cells. [ABSTRACT FROM AUTHOR]

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−.