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Introduction: The objective of this study was to describe the implementation and outcomes of a protocol outlining angiotensin-II utilization for vasoplegia following cardiac surgery. Methods: This was a retrospective chart review at a single-center university hospital. Included patients received angiotensin-II for vasoplegia refractory to standard interventions, including norepinephrine 20 mcg/min and vasopressin 0.04 units/min, following cardiac surgery between April 2021 and April 2022. Results: 30 patients received angiotensin-II for refractory vasoplegia. Adjunctive agents at angiotensin-II initiation included corticosteroids (26 patients; 87%), epinephrine (26 patients; 87%), dobutamine (17 patients; 57%), dopamine (9 patients; 30%), milrinone (2 patients; 7%), and hydroxocobalamin (4 patients; 13%). At 3 hours, the median mean arterial pressure increased from baseline (70 vs 61.5 mmHg, p =.0006). Median norepinephrine doses at angiotensin-II initiation, 1 hour, 3 hours, and angiotensin-II discontinuation were 0.22, 0.16 (p =.0023), 0.10 (p <.0001), and 0.07 (p <.0001) mcg/kg/min. Median dobutamine doses decreased throughout angiotensin-II infusion from eight to six mcg/kg/min (p =.0313). Other vasoactive medication doses were unchanged. Three patients (10%) subsequently received hydroxocobalamin. Thirteen (43.3%) and five (16.7%) patients experienced mortality by day 28 and venous or arterial thrombosis events, respectively. Conclusions: The administration of angiotensin-II to vasoplegic patients following cardiac surgery was associated with increased mean arterial pressure, reduced norepinephrine dosages, and reduced dobutamine dosages. [ABSTRACT FROM AUTHOR]

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]

Background: The appropriate third-line vasopressor in septic shock patients receiving norepinephrine and vasopressin is unknown. Angiotensin-II (AT-II) offers a unique mechanism of action to traditionally used vasopressors in septic shock. Objective: The objective of this study was to compare the clinical efficacy and safety of third-line AT-II to epinephrine in patients with septic shock. Methods: A single-center, retrospective cohort study of critically ill patients was performed between April 1, 2019 and July 31, 2022. Propensity-matched (2:1) analysis compared adults with septic shock who received third-line AT-II to controls who received epinephrine following norepinephrine and vasopressin. The primary outcome was clinical response 24 hours after third-line vasopressor initiation. Additional efficacy and safety outcomes were investigated. Results: Twenty-three AT-II patients were compared with 46 epinephrine patients. 47.8% of AT-II patients observed a clinical response at hour 24 compared with 28.3% of epinephrine patients (P = 0.12). In-hospital mortality (65.2% vs 73.9%, P = 0.45), cardiac arrhythmias (26.1% vs 26.1%, P = 0.21), and thromboembolism (4.3% vs 2.2%, P = 0.61) were not observed to be statistically different between groups. Conclusions and relevance: Administration of AT-II as a third-line vasopressor agent in septic shock patients was not associated with significantly improved clinical response at hour 24 compared with epinephrine. Although underpowered to detect meaningful differences, the clinical observations of this study warrant consideration and further investigation of AT-II as a third-line vasopressor in septic shock. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) is characterized by an increase of a pressure in the pulmonary circulation; PAH is accompanied by activation of the sympathetic (SNS) and the renin-angiotensin-aldosterone system (RAAS). However, PAH-associated changes in baroreceptor regulation of systemic circulation, which is tightly interwoven with SNS and RAAS, have not been studied. The baroreceptor response (BRR) was studied in a chronic monocrotaline (MCT) model of PAH in rats (Wistar, 290 ± 30 g, 2–4 months). Phenylephrine as an agonist of α1-adrenergic receptor and sodium nitroprusside as NO donor were gradually administered to chronically catheterized, non-anesthetized control animals and animals with PAH (4 weeks after MCT administration) to induce vasomotor responses. Mean arterial pressure and heart rate (HR) were recorded under the action of vasoactive compounds alone or under the action of vasoactive compounds in presence of angiotensin-II (ATII), atropine. The parameters characterizing baroreceptor change in HR including maximal and minimal heart rate (HRmax, HRmin), reflex tachycardia (TBRR) and bradycardia (BBRR), range (ABRR) and the baroreceptor response sensitivity index (SIBRR) were calculated. A significant decrease in HRmax, TBRR, ABBR (but not BBRR), as well as the sensitivity index of BRR was observed in rats with PAH. ATII induces significant and different changes in the BRR parameters in control rats and in rats with PAH if administered 4 weeks after the start of the experiment. In rats with PAH, ATII causes less pronounced changes in HRmax, TBRR, and BBRR than in control animals. ATII insignificantly affects parasympathetic component of the baroreceptor reflex in rats with PAH. Thus, at least in the MCT-mediated model in rats, PAH significantly deteriorates the baroreceptor regulation of HR. This effect manifests in a decrease in the range and sensitivity of the baroreceptor response. Also, PAH unequally affects the sympathetic and parasympathetic control of the baroreceptor regulation of HR. On the other hand, ATII exhibits weak ability to alter BRR in rats with HAP. In conclusion, PAH leads to a disfunction of immediate, reflex mechanisms HR and systemic circulation control. [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 early myocardial response of hypertension is an elevation of angiotensin‐II (Ang‐II) concentration, leading to heart failure and cardiac hypertrophy. This hypertrophic event of the heart is mediated by the interaction of Ang type 1 receptors (AT‐R1), thereby modulating NADPH oxidase activity in cardiomyocytes, which alters redox status in cardiomyocytes. Ellagic acid (EA) has anti‐inflammatory and anti‐oxidative capacities. Thus, EA has potential preventive effects on cardiovascular diseases and diabetes. In the last decades, because the protective effect of EA on Ang‐II‐induced hypertrophic responses is unclear, this study aims to investigate the protective effect of EA in cardiomyocytes. H9c2 cells were treated to Ang‐II 1 μM for 24 h to induce cellular damage. We found that EA protected against Ang‐II‐increased cell surface area and pro‐hypertrophic gene expression in H9c2. EA reduced Ang‐II‐caused AT‐R1 upregulation, thereby inhibiting oxidative stress NADPH oxidase activation. EA mitigated Ang‐II‐enhanced p38 and extracellular‐signal‐regulated kinase (ERK) phosphorylation. Moreover, EA treatment under Ang‐II stimulation also reversed NF‐κB activity and iNOS expression. This study shows that EA protects against Ang‐II‐induced myocardial hypertrophy and attenuates oxidative stress through reactive oxygen species‐mediated mitogen‐activated protein kinase signaling pathways in H9c2 cells. Thus, EA may be an effective compound for preventing Ang‐II‐induced myocardial hypertrophy. [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]

Myocardial hypertrophy plays a crucial role in cardiovascular disease (CVD) development. Myocardial hypertrophy is an adaptive response by myocardial cells to stress after cardiac injury to maintain cardiac output and function. Angiotensin II (Ang‐II) regulates CVD through the renin‐angiotensin‐aldosterone system, and its signaling in cardiac myocytes leads to excessive reactive oxygen species (ROS) production, oxidative stress, and inflammation. Sesamin (SA), a natural compound in sesame seeds, has anti‐inflammatory and anti‐apoptotic effects. This study investigated whether SA could attenuate hypertrophic damage and oxidative injuries in H9c2 cells under Ang‐II stimulation. We found that SA decreased the cell surface area. Furthermore, Ang‐II treatment reduced Ang‐II‐increased ANP, BNP, and β‐MHC expression. Ang‐II enhanced NADPH oxidase activity, ROS formation, and decreased Superoxide Dismutase (SOD) activity. SA treatment reduces Ang‐II‐caused oxidative injuries. We also found that SA mitigates Ang‐II‐induced apoptosis and pro‐inflammatory responses. In conclusion, SA could attenuate Ang‐II‐induced cardiac hypertrophic injuries by inhibiting oxidative stress, apoptosis, and inflammation in H9c2 cells. Therefore, SA might be a potential supplement for CVD management. [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy accompanies numerous cardiovascular diseases, and the intervention of cardiac hypertrophy is an important issue to prevent detrimental consequences. Mangiferin (MGN) is a glucosylxanthone found in Mangifera indica, which exhibits anti-oxidant and anti-inflammatory properties. Various studies have demonstrated the cardioprotective potential of MGN, but the mechanisms behind its beneficial effects have not been fully revealed. Here, angiotensin-II (Ang-II) was used to induce cardiac hypertrophy, and we examined cell size, expression of hypertrophy markers (e.g., ANP, BNP, and β -MHC), and oxidative stress (e.g., the ratio of NADPH/NADP + , the expression of p22phox and p67phox, and ROS and SOD production) of cardiomyocytes. Moreover, we assessed the activation of mitogen-activated protein kinase (MAPK) signaling (e.g., p38 and ERK) and the NF- κ Bp65/iNOS axis. Additionally, an annexin V/PI assay was employed to evaluate whether MGN administration can attenuate Ang-II-elicited apoptosis. Lastly, the expression of Ang-II type 1 receptor (AT1) was measured to confirm its involvement in MGN-mediated protection. Our results showed that treatment with MGN attenuated the Ang-II-induced cell size, expression of hypertrophy markers, and oxidative stress in cardiomyocytes. MGN also abrogated the activation of MAPK signaling and the NF- κ Bp65/iNOS axis. Additionally, MGN prevented apoptosis and downregulated the elevation of AT1 in cardiomyocytes that had been exposed to Ang-II. Altogether, these results demonstrated the potential of using MGN to ameliorate the Ang-II-associated cardiac hypertrophy, which may be due to its anti-oxidant and anti-inflammatory effects through suppression of MAPK signaling and the NF- κ Bp65/iNOS axis. [ABSTRACT FROM AUTHOR]

• ACE-inhibitors are commonly used for the management of cardiovascular diseases. • They are usually well tolerated but can be responsible for a dry cough due to a bradykinin related mechanism of action. • The incidence of cough is influenced by age, gender, concomitant diseases, type of study and characteristics of single molecules within the class. • Cough should be carefully evaluated in the single patients to exclude any drug-independent cause. • Drugs more active at the levels of the tissue RAS (Perindopril, Zofenopril) could be less responsible for cough. Angiotensin converting enzyme inhibitors (ACEi) have consistently demonstrated improved survival and reduced risk of major cardiovascular events, across the spectrum of cardiovascular disease, including hypertension, coronary artery disease, myocardial infarction, and heart failure. The cardioprotective effects of ACEi result from inhibiting the conversion of angiotensin I to angiotensin II, and inhibition of bradykinin degradation. They are generally well tolerated but may cause the onset of a dry cough in some patients. This review presents current evidence on the incidence and mechanisms of cough associated with ACEi use, and then considers how to manage ACEi-related cough in clinical practice. The incidence of ACEi-induced cough in the published literature varies widely due to heterogeneity in the source data and lack of adequate controls. Incidence also varies among individual ACEi with agents such as perindopril, which has a high tissue ACE affinity, associated with a lower rate of cough. Evidence from real-world studies shows that the incidence of ACEi-associated cough is lower than rates reported in clinical trials. Patients who experience any dry cough are often switched to angiotensin- receptor blockers or other classes of antihypertensive drugs, regardless of cough severity. To avoid inappropriate discontinuation of ACEi in clinical practice, an alternative approach in patients with persistent cough is to perform a challenge/re-challenge to determine if re-introduction of ACEi is associated with recurrence of symptoms. Incidence of cough should not be considered a class effect for ACEi, and the patient may benefit by a switch from one ACEi to another. Every effort should be made to enable patients to continue ACEi therapy to reduce adverse cardiovascular outcomes and improve survival. [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]

The renin-angiotensin-aldosterone system (RAAS), whose major vasopressor effector is angiotensin II (ATII), has multiple activities and regulates sodium-water homeostasis and fluid and blood pressure homeostasis. RAAS plays a crucial role in cardiocirculatory shock because it counteracts hypotension and hypovolemia by activating different physiologic responses. Based on the encouraging results of the ATHOS-3 trial, the US Food and Drug Administration and the European Medicines Agency approved the use of ATII for catecholamine-resistant vasodilatory shock. More recently, ATII was used for the compassionate treatment of critically ill patients with COVID-19. Beyond its vasopressor properties, ATII was hypothesized to have antiviral activity because it induces internalization and degradation of angiotensin-converting enzyme 2 receptors used by SARS-Cov-2 to infect cells. Overall, the use of ATII in patients with COVID-19 showed promising results because its administration was associated with the achievement and maintenance of target mean arterial pressure, increased P a O 2 /F I O 2 ratio, and decreased F I O 2. The aim of this narrative review is to summarize the available knowledge on the use of ATII in patients with COVID-19. [ABSTRACT FROM AUTHOR]

Atrial fibrosis is associated with the occurrence of atrial fibrillation (AF) and regulated by the transforming growth factor-β1 (TGF-β1)/Smad2/3 signalling pathway. Unfortunately, the mechanisms of regulation of TGF-β1/Smad2/3-induced atrial fibrosis and vulnerability to AF remain still unknown. Previous studies have shown that sirtuin3 (SIRT3) sulfhydration has strong anti-fibrotic effects. We hypothesised that SIRT3 sulfhydration inhibits angiotensin II (Ang-II)-induced atrial fibrosis via blocking the TGF-β1/Smad2/3 signalling pathway. In this study, we found that SIRT3 expression was decreased in the left atrium of patients with AF compared to that in those with sinus rhythm (SR). In vitro , SIRT3 knockdown by small interfering RNA significantly expanded Ang-II-induced atrial fibrosis and TGF-β1/Smad2/3 signalling pathway activation, whereas supplementation with Sodium Hydrosulfide (NaHS, exogenous hydrogen sulfide donor and sulfhydration agonist) and SIRT3 overexpression using adenovirus ameliorated Ang-II-induced atrial fibrosis. Moreover, we observed suppression of the TGF-β1/Smad2/3 pathway when Ang-II was combined with NaHS treatment, and the effect of this co-treatment was consistent with that of Ang-II combined with LY3200882 (Smad pathway inhibitor) on reducing atrial fibroblast proliferation and cell migration in vitro. Supplementation with dithiothreitol (DTT, a sulfhydration inhibitor) and adenovirus SIRT3 shRNA blocked the ameliorating effect of NaHS and AngII co-treatment on atrial fibrosis in vitro. Finally, continued treatment with NaHS in rats ameliorated atrial fibrosis and remodelling, and further improved AF vulnerability induced by Ang-II, which was reversed by DTT and adenovirus SIRT3 shRNA, suggesting that SIRT3 sulfhydration might be a potential therapeutic target in atrial fibrosis and AF. [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.

An imbalance in the renin-angiotensin system (RAS) is associated with cognitive decline and disease pathology in Alzheimer's disease (AD). In this study, we have investigated changes in the brain angiotensin-converting enzyme-1 (ACE-1) and angiotensin-II (Ang-II), and the counter-regulatory angiotensin-converting enzyme-2 (ACE-2), in the frontal and temporal cortex during normal aging and in the early stages of AD. We studied a cohort of normal aging (n = 121; 19-95 years age-at-death) from the Sudden Death Brain Bank, University of Edinburgh, United Kingdom, and AD and age-matched controls (n = 60) from the South West Dementia Brain Bank, University of Bristol, United Kingdom, stratified according to Braak tangle stage (BS): 0-II, III-IV (intermediate disease), and V-VI (end-stage disease). ACE-1 and ACE-2 enzyme activity were measured using fluorogenic peptide activity assays. ACE-1, ACE-2, and Ang-II protein level were measured by enzyme-linked immunosorbent assay (ELISA). In both regions, ACE-1 protein and Ang-II levels correlated positively with age whereas ACE-1 enzyme activity was inversely related to age. ACE-1 protein correlated positively with Ang-II, whilst ACE-1 activity correlated inversely with Ang-II in normal aging. ACE-1 enzyme activity was elevated at an early/intermediate stage, BS III-IV compared to BS 0-II in the temporal cortex in AD. ACE-2 protein and enzyme activity were unchanged with aging and in AD. In conclusion, ACE-1 activity is induced in the early stages of AD independently from normal physiological age-related changes in ACE-1 protein. [ABSTRACT FROM AUTHOR]

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.

Sepsis is an extensive life‐threatening illness that occurs due to an abnormal host response that extends through the initial storm of inflammation and oxidative stress and terminates at the late stage of immunosuppression. Among global intensive care units, sepsis‐induced acute kidney injury is reported with high mortality rate. The purpose of this study was to evaluate the protective effect of the renin angiotensin aldosterone system (RAAS) inhibition on sepsis outcomes. Cecal ligation and puncture (CLP) procedure was applied for sepsis induction. The experimental design constituted of five groups of rats: sham, CLP‐nontreated and CLP‐treated with ramipril (10 mg/kg, p.o.), losartan (20 mg/kg, i.p.) and spironolactone (25 mg/kg, p.o.). Twenty‐four hours after surgery, rats were euthanized for blood and tissue samples, which were used for assessment of serum inflammatory markers, and oxidative stress parameters, as well as to kidney function parameters. The tissue samples were used for histological and caspase‐3 assessment. A survival study was conducted using another set of animals. Our results showed that the different RAAS inhibitors showed protective effects evidenced by enhanced overall survival following sepsis (80% in ramipril and spironolactone‐treated and 60% in losartan‐treated vs. 10% in the septic group), in addition to improved renal function parameters and reduction of oxidative stress and inflammation. The timely use of RAAS inhibitors during sepsis might represent a new therapeutic approach in septic patient. [ABSTRACT FROM AUTHOR]

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]

Objective To observe the effects of adiponectin（APN）on angiotensin-Ⅱ（Ang Ⅱ）-induced cardiac fibroblasts（ CFs）proliferation and extracellular signal-regulated kinase 1/2（ERK1/2）activation. Methods Cardiac ventricles were separated from 1 to 3-day-old C57 mice. Pure primary mouse cardiac fibroblasts were obtained after cardiomyocytes were separated by trypsin-collagenase type I digestion and differential adhesion. Morphological and immunocytochemical technique was used to identify the CFs. CFs of two to four generations were randomly divided into five groups. CFs in the control group were cultured with serum-free DMEM medium. CFs in the Ang II group were cultured with DMEM medium containing 10-7 mol/L Ang II. CFs in the low-dose，medium-dose and high-dose APN groups were treated with 1，5 and 25 μg/mL APN for 1 h，respectively，and then were cultured with DMEM medium containing 10-7 mol/L Ang II. The cells were collected after 24 h culture. The proliferation ability（OD）of CFs was measured by MTT，the expression of ERK1/2 and phosphorylated extracellular signal-regulated kinase 1/2（p-ERK1/2）in CFs was detected by Western blotting，and the p-ERK/ERK ratio was calculated. Results CFs were successfully isolated from mouse heart， and the cell purity was close to 100% by immunofluorescence combined with morphological identification. Compared with the control group，the OD value of the Ang II group increased（P<0. 05）；compared with the Ang II group，OD values of the APN groups were lower（all P<0. 05）；there was no statistically significant difference in OD value among APN groups （P>0. 05）. There was no statistically significant difference in the relative expression of ERK1/2 protein among all groups （P>0. 05）. Compared with the control group，the relative expression of p-ERK protein and the ratio of p-ERK/ERK were higher in the Ang II group（all P<0. 05）. Compared with the Ang II group，p-ERK protein relative expression level and the ratio of p-ERK/ERK were lower in the high-dose APN group（all P<0. 05）. Conclusion Adiponectin inhibits the proliferation of CFs and the activation of ERK1/2 signal induced by Ang II. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the effects of miR-29b on renal interstitial fibrosis in the obstructed kidney of mouse with unilateral ureteral obstruction (UUO) via inhibiting phosphatidylinositol 3-kinase/protein kinaseB (PI3K/AKT) signaling pathway. Methods: Adult male CD-1 mice were intraperitoneally injected with vehicle or PI3K inhibitor LY294002 (3 mg/kg, 30 mg/kg) daily for 1 or 2 weeks after performing UUO or sham operation. The mice were sacrificed on days 7 and 14 after surgery. The rat proximal tubular epithelial cell (TEC) line NRK-52E was cultured in DMEM and treated with various concentrations angiotensin II (AngII). Obstructed and sham mouse kidneys were analyzed via HE, Masson and immunohistochemistry to assess the degree of renal fibrosis. Real-time quantitative polymerase chain reaction assays (RT-PCR) were performed to investigate changes in the levels of expression of miR-29b and Western blot was used to analyze the activation of PI3K/AKT signaling and expression of E-cadherin, α-smooth muscle actin (α-SMA). Results: Histologic analyses of obstructed kidney revealed that LY294002 attenuated the degree of renal fibrosis. In this study, loss of miR-29b accompanied with increased epithelial–mesenchymal transition (EMT) was observed in renal tubules of mice after UUO and cultured NRK-52E cells exposed to AngII. LY294002 also prominently decreased phosphorylation of AKT in vivo and vitro. By RT-PCR and Western blot analysis, LY294002 blocked the PI3K/AKT-induced loss of E-cadherin expression and de novo increase of the expression of α-SMA in a time- and dose-dependent manner. The overexpression of miR-29b markedly reversed the phenotype induced by AngII in NRK-52E cells and the downregulation miR-29b expression with an miR-29b inhibitor resulted in enhanced EMT. In addition, the PI3K/AKT signaling pathway was found to be suppressed in the presence of overexpression of miR-29b by direct hybridization with 3′-untranslated region (3′-UTR) of PIK3R2. Conclusion: Our findings suggested that miR-29b significantly prevented tubulointerstitial injury in mouse model of UUO by attenuating renal tubular epithelial cell–mesenchymal transition via repressing PI3K/AKT signaling pathway. [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.

Previously, we have reported that the coronary reactive hyperemic response was reduced in adenosine A2A receptor-null (A2AAR−/−) mice, and it was reversed by the soluble epoxide hydrolase (sEH) inhibitor. However, it is unknown in aortic vascular response, therefore, we hypothesized that A2AAR-gene deletion in mice (A2AAR−/−) affects adenosine-induced vascular response by increase in sEH and adenosine A1 receptor (A1AR) activities. A2AAR−/− mice showed an increase in sEH, AI AR and CYP450-4A protein expression but decrease in CYP450-2C compared to C57Bl/6 mice. NECA (adenosine-analog) and CCPA (adenosine A1 receptor-agonist)-induced dose-dependent vascular response was tested with t-AUCB (sEH-inhibitor) and angiotensin-II (Ang-II) in A2AAR−/− vs. C57Bl/6 mice. In A2AAR−/−, NECA and CCPA-induced increase in dose-dependent vasoconstriction compared to C57Bl/6 mice. However, NECA and CCPA-induced dose-dependent vascular contraction in A2AAR−/− was reduced by t-AUCB with NECA. Similarly, dose-dependent vascular contraction in A2AAR−/− was reduced by t-AUCB with CCPA. In addition, Ang-II enhanced NECA and CCPA-induced dose-dependent vascular contraction in A2AAR−/− with NECA. Similarly, the dose-dependent vascular contraction in A2AAR−/− was also enhanced by Ang-II with CCPA. Further, t-AUCB reduced Ang-II-enhanced NECA and CCPA-induced dose-dependent vascular contraction in A2AAR−/− mice. Our data suggest that the dose-dependent vascular contraction in A2AAR−/− mice depends on increase in sEH, A1AR and CYP4A protein expression. [ABSTRACT FROM AUTHOR]

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.

Angiotensin-II (Ang-II) receptor plays a role in allergic airway inflammation; however, the underlying mechanism and role of macrophages need better understanding. In the present study, angiotensin-II infusion (1 μg/kg/min) in ovalbumin-induced airway inflammation mice model significantly decreased immune cell infiltration, goblet cell hyperplasia, and eosinophil numbers in lungs. Ang-II infusion increased M1 and decreased M2 macrophage population in bronchoalveolar lavage fluid and respective macrophage markers in lung macrophages. Similarly, in vitro Ang-II treatment in murine bone marrow-derived macrophages (BMDMs) induced M1 and reduced M2 macrophage phenotype with enhanced bactericidal activity. Mechanistically, Ang-II inhibits Let-7c and miR-99a expression in BMDMs and in vivo as well. Lentiviral overexpression of Let-7c and miR-99a miRNAs in BMDMs abrogated Ang-II-induced M1 phenotype activation and promoted M2 phenotype, which is governed by targeting TNFα by miR-99a. In lung macrophages, ovalbumin-induced TNFα inhibition was rescued after Ang-II treatment. In BMDMs, knockdown of TNFα abrogated Ang-II-induced M2 to M1 macrophage phenotype switch and associated bactericidal activity. Ang-II affects mature miRNA formation by enhancing Lin28B levels in macrophages in vivo and in vitro. Furthermore, Lin28B knockdown prevented Ang-II-mediated inhibition of mature Let-7c/miR-99a miRNA formation, M2 to M1 macrophage phenotype switch, and increased bactericidal activity. Therefore, present study suggests a role of Lin28B in Ang-II-induced Let-7c/miR-99a miRNA formation that consequently affects TNFα production, M1 phenotype activation, and allergic airway inflammation. [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). 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]

Animal models of aortic aneurysm and dissection can enhance our limited understanding of the etiology of these lethal conditions particularly because early-stage longitudinal data are scant in humans. Yet, the pathogenesis of often-studied mouse models and the potential contribution of aortic biomechanics therein remain elusive. In this work, we combined micro-CT and synchrotron-based imaging with computational biomechanics to estimate in vivo aortic strains in the abdominal aorta of angiotensin-II-infused ApoE-deficient mice, which were compared with mouse-specific aortic microstructural damage inferred from histopathology. Targeted histology showed that the 3D distribution of micro-CT contrast agent that had been injected in vivo co-localized with precursor vascular damage in the aortic wall at 3 days of hypertension, with damage predominantly near the ostia of the celiac and superior mesenteric arteries. Computations similarly revealed higher mechanical strain in branching relative to non-branching regions, thus resulting in a positive correlation between high strain and vascular damage in branching segments that included the celiac, superior mesenteric, and right renal arteries. These results suggest a mechanically driven initiation of damage at these locations, which was supported by 3D synchrotron imaging of load-induced ex vivo delaminations of angiotensin-II-infused suprarenal abdominal aortas. That is, the major intramural delamination plane in the ex vivo tested aortas was also near side branches and specifically around the celiac artery. Our findings thus support the hypothesis of an early mechanically mediated formation of microstructural defects at aortic branching sites that subsequently propagate into a macroscopic medial tear, giving rise to aortic dissection in angiotensin-II-infused mice. [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.

Pathological cardiac hypertrophy (PCH) is characterized by an increase in cardiomyocyte size and thickening of the ventricular walls during the adaptive response to maintain cardiac function, which often progresses to a maladaptive response and, ultimately, to heart failure. Previous studies have demonstrated that miRNAs play roles in the pathogenesis of PCH. In this study, we first found that the regulation of miR-338-5p was aberrant in cardiac tissues of heart failure patients and transverse aortic constriction (TAC)-induced PCH mice. Overexpression of miR-338-5p in the heart using recombinant adeno-associated virus serotype 9 (rAAV9) ameliorated TAC-induced PCH, as indicated by a decreased heart weight/body weight (HW/BW) ratio. Furthermore, miR-338-5p mitigated the TAC-induced damage in heart contraction and relaxation function, as measured by echocardiography and a cardio hemodynamic measurement, respectively. We also identified CAMKIIδ as a direct target of miR-338-5p using bioinformatics tools and the luciferase reporter assay. Finally, we observed that the miR-338-5p-mediated downregulation of CAMKIIδ reversed the cell surface area enlargement induced by the Ang-II treatment in H9c2 cells. Therefore, we highlight a novel molecular mechanism of the miR-338-5p/CAMKIIδ axis that contributes to the pathogenesis of PCH. [ABSTRACT FROM AUTHOR]

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.

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.