Angiotensin II Levels Research Articles

Valsartan as a prophylactic treatment against breast cancer development and niche activation: What molecular sequels follow chronic AT-1R blockade?

AimsTransactivation of insulin-growth-factor-receptor (IGF-1R) by angiotensin-II-type-1-receptor (AT-1R) was only demonstrated in vascular-smooth-muscle cells and has never been tested in breast-cancer (BC). This investigation addressed the impact of chronic AT-1R blockade by valsartan (Val) on possible concurrent AT-1R/IGF-1R signaling inhibition, regressing BC-tumor-microenvironment (TME) cellular components activation, and hindering BC development. Main methodsThe effect of different Val doses (10, 20, 40 & 80 mg/kg/day for 490 days) was tested on dimethylbenz(a)anthracene (DMBA)-induced progesterone-promoted-BC in rats. The influence on intratumoral/circulating angiotensin-II (ANG-II) levels and AT-1R/Mas-R immunofluorescent-expression were assessed. The potential AT-1R/IGF-1R crosstalk within TME-BC-stem-cells (BCSCs) and cancer-associated-fibroblasts (CAFs) was evaluated by fluorescently marking these cells and locating the immunofluorescently-stained AT-1R/IGF-1R in them using confocal-laser-microscopy and further quantified by flow cytometry. In addition, the molecular alterations following blocking AT-1R were inspected including determining Src; crucial for IGF-1R transactivation by AT-1R, Notch-1; IGF-IR transcriptional-regulator, and PI3K/Akt &IL-6/STAT expression. Further, the suppression of CSCs' capabilities to maintain pluripotency, stemness features, epithelial-to-mesenchymal-transition (EMT), and angiogenesis was evaluated by assessing NANOG gene, aldehyde-dehydrogenase (ALDH), N-cadherin and vascular-endothelial-growth-factor (VEGF), respectively. Furthermore, the proliferative marker; Ki-67, was detected by immunostaining, and tumors were histologically graded using Elston-Ellis-modified-Scarff-Bloom-Richardson method. Key findingsProphylactic Val significantly reduced tumor size, prolonged latency, reduced tumor histopathologic grade, decreased circulating/intratumoral-ANG-II levels, increased Mas-R, and decreased AT1R expression. AT-1R/IGF-1R were co-expressed with a high correlation coefficient on CAFs/BCSCs. Moreover, Val significantly attenuated IGF-1R transactivation and transcriptional regulation via Src and Notch-1 genes' downregulation and reduced Src/IGF-IR-associated PI3K/Akt and IL-6/STAT3 signaling. Further, Val significantly decreased intratumoral NANOG, ALDH, N-cadherin, VEGF, and Ki-67 levels. SignificanceChronic Val administration carries a potential for repurposing as adjuvant or conjunct therapy for patients at high risk for BC.

The Antihypertensive Potential of Aqueous extract of Peristrophe Bivalvis (L.) Merr. is via Up-regulation of Cyclic Guanosine Monophosphate and Down-regulation of the Renin-angiotensin System.

Hypertension is a major risk factor for cardiovascular diseases. Peristrophe bivalvis (PB) is used for the treatment of hypertension, painful sprains, skin diseases, tuberculosis, acute bronchitis, anti-inflammatory conditions, hepatitis, and diabetes. Its antihypertensive potential has been investigated and documented. This study investigated the antihypertensive mechanism of aqueous extract of PB leaf (APB) on L-NAME-induced hypertension. Thirty male wistar rats (150-170 g) were grouped into five (n=5). Group 1 received 10 mL/kg of distilled water (control), while groups 2-5 were administered 60 mg/kg of L-NAME (L-- NAME60) orally for eight weeks to induce hypertension. After eight weeks, groups 2-5 received L-NAME60+distilled water (HNT), distilled water (HRE), L-NAME60+APB (200 mg/kg, [HAPB]), and L-NAME60+ramipril (10 mg/kg, [HRA]), respectively, for five weeks. The BP was measured by the tail-cuff method. The blood sample was obtained under anesthesia, and tissue samples were obtained after euthanasia. Serum renin, ACE, angiotensin-II, endothelin-1, and cyclic guanosine monophosphate (cGMP) levels were measured using ELISA techniques. Malondialdehyde, superoxide dismutase (SOD), and reduced glutathione (GSH) levels were measured by spectrophotometry. Data were analyzed using ANOVA at α0.05. The BP significantly decreased in HAPB compared to HNT. Renin, ACE, and angiotensin-II levels significantly decreased while cGMP levels increased in the HAPB group compared to HNT. Malondialdehyde levels significantly decreased, and SOD and GSH levels increased compared to HNT. Peristrophe bivalvis aqueous leaf extract reduced blood pressure in hypertensive rats by modulating the cGMP signalling pathway and the renin-angiotensin system.

Serum Angiotensin II Level in Pediatric Patients with COVID-19 and its Correlation with the Disease Severity

Abstract Background Coronavirus disease 2019 (COVID-19) is a newly discovered RNA betacoronavirus infection. It has been caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Angiotensin II (Ang-II) is a mitochondrial toxin that under normal circumstances is rapidly removed by angiotensin converting enzyme 2 (ACE-2). SARS-CoV-2 uses the receptor ACE-2 for host cell entry and viral replication. ACE-2 proteins are occupied and downregulated by SARS-CoV-2. ACE-2 downregulation has been directly linked to toxic over accumulation of Ang-II. Accumulating Ang-II triggers many severe and fatal conditions such as acute respiratory distress syndrome (ARDS). Aim of the Work To assess the serum level of Ang-II and correlate it with the severity of COVID-19 infection in pediatric patients. Patients and Methods This case control study was conducted on 45 positive COVID-19 RT-PCR children who were compared to age and sex matched 45 healthy controls. Clinical examination, laboratory assays and imaging studies were done for the patients group to assess the severity of COVID–19 infection. Serum Ang-II was measured by ELISA for both groups and correlated with clinical (heart rate, blood pressure, respiratory rate and oxygen saturation), laboratory (total leucocytic count, lymphocytes, neutrophils, serum ferritin, ESR and CRP) and radiological (chest x-ray and CORAD score of CT chest ) parameters of the patients. Results The median “IQR” of serum Ang-II was significantly higher in the COVID-19 patients than in the controls (100 (88-137) ng/L) versus 20 (15-25) ng/L) (p-value= 0.001). There were statistically significant positive correlations between serum Ang-II levels and different grades of clinical severity classification (rs = 0.92, p-value=0.001) and CORAD score of CT chest. On the other hand, no statistically significant correlations were found between serum levels of Ang-II and total leucocytic count, lymphocytes, neutrophils, ESR and CRP. Conclusion Serum Ang-II could be used as a biomarker in predicting the severity of COVID-19 infection in pediatrics.

Differential effects of cholecalciferol and calcitriol on muscle proteolysis and oxidative stress in angiotensin II-induced C2C12 myotube atrophy.

Renin-angiotensin system activation contributes to skeletal muscle atrophy in aging individuals with chronic diseases. We aimed to explore the effects of cholecalciferol (VD3) and calcitriol (1,25VD3) on signaling of muscle proteolysis and oxidative stress in myotubes challenged with angiotensin II (AII). The mouse C2C12 myotubes were assigned to vehicle, AII, AII + VD3, AII + 1,25VD3, and AII + losartan groups. The expression levels of muscle-specific E3 ubiquitin ligase proteins, autophagy-related proteins, and oxidative stress markers were investigated. We demonstrated the diverse effects of VD3 and 1,25VD3 on AII-induced myotube atrophy. The myotube diameter was preserved by treatment with 100 nM VD3 and losartan, while 1 and 10 nM 1,25VD3 increased levels of FoxO3a, MuRF1, and atrogin-1 protein expression in myotubes exposed to AII. Treatment with AII + 10 nM 1,25VD3 resulted in the upregulation of LC3B-II, LC3B-II/LC3B-I, and mature cathepsin L, which are autophagic marker proteins. The p62/SQSTM1 protein was downregulated and vitamin D receptor was upregulated after treatment with AII + 10 nM 1,25VD3. A cellular redox imbalance was observed as AII + 10 nM 1,25VD3-induced reactive oxygen species and NADPH oxidase-2 overproduction, and these changes were associated with an inadequate response of antioxidant superoxide dismutase-1 and catalase proteins. Collectively, these findings provide a translational perspective on the role of vitamin D3 in alleviating muscle atrophy related to high levels of AII.

Early Low-Grade Inflammation Induced by High-Salt Diet in Sprague Dawley Rats Involves Th17/Treg Axis Dysregulation, Vascular Wall Remodeling, and a Shift in the Fatty Acid Profile.

Unrestricted increased table salt (NaCl) intake is associated with oxidative stress and inflammation, leading to endothelial dysfunction and atherosclerosis. However, data on salt-induced immunomodulatory effects in the earliest phase of salt loading are scarce. In the present study, an animal model of short-term salt loading was employed, including male Sprague Dawley rats consuming a high-salt diet (HSD; 4% NaCl) or standard laboratory chow (low-salt; LSD; 0.4% NaCl) during a 7-day period. The contribution of angiotensin II (ANGII) suppression was tested by adding a group of rats on a high-salt diet receiving ANGII infusions. Samples of peripheral blood/mesenteric lymph node leukocytes, brain blood vessels, and serum samples were processed for flow cytometry, quantitative real-time PCR, total proteome analysis, and multiplex immunoassay. Data analysis revealed the up-regulation of Il 6 gene in the microcirculation of high-salt-fed rats, accompanied by an increased serum level of TNF-alpha cytokine. The high-salt diet resulted in increased proportion of serum mono-unsaturated fatty acids and saturated fatty acids, reduced levels of linoleic (C18:2 ω-6) and α-linolenic (C18:3 ω-3) acid, and increased levels of palmitoleic acid (C16:1 ω-7). The high-salt diet had distinct, lymphoid compartment-specific effects on leukocyte subpopulations, which could be attributed to the increased expression of salt-sensitive SGK-1 kinase. Complete proteome analysis revealed high-salt-diet-induced vascular tissue remodeling and perturbations in energy metabolism. Interestingly, many of the observed effects were reversed by ANGII supplementation. Low-grade systemic inflammation induced by a HSD could be related to suppressed ANGII levels. The effects of HSD involved changes in Th17 and Treg cell distribution, vascular wall remodeling, and a shift in lipid and arachidonic acid metabolism.

Imbalance Between Angiotensin II and Kallikrein in Patients With ST-Segment Elevation Myocardial Infarction: A Case-Control Emergency Room Study.

The present study aimed to investigate the balance between angiotensin II (Ang-II) and kallikrein (KLK1) in the pathogenesis of ST-segment elevation acute myocardial infarction (STEMI). The study included a total of 261 participants: 151 STEMI patients and 110 individuals with normal coronary arteries. The plasma levels of Ang-II and KLK1 were measured using enzyme-linked immunosorbent assays (ELISA). Multivariate logistic regression analysis indicated that the plasma levels of Ang-II, KLK1 and the ratio of Ang-II and KLK1 (Ang-II/KLK1) independently correlated with the presence of STEMI. Furthermore, we found independent associations between STEMI and smoking, cholesterol (CHO), high-density lipoprotein cholesterol (HDL-c), as well as age. The ratio of Ang-II/KLK1 correlated with the plasma level of the inflammatory cytokine, interleukin-6 (IL-6). Both Ang-II and KLK1 levels are significantly elevated in patients with STEMI. An increased Ang-II/KLK1 ratio may result in the over-activation of Ang-II and exacerbate the progression of STEMI(P = .046). In conclusion, we have demonstrated, for the first time, an Ang-II and KLK1 imbalance in patients with STEMI.

Qiliqiangxin capsule alleviates cardiac hypertrophy and cardiac dysfunction by regulating miR-382-5p/ATF3 axis

ObjectiveQiliqiangxin Capsule (QL) was investigated for its possible role in cardiac hypertrophy in this study. MethodsQL (0.5 mg/mL) was pre-treated in Neonatal Mouse Ventricular Cardiomyocytes (NMVCs) before induction of cardiomyocyte hypertrophy by Angiotensin II (Ang-II). Immunofluorescence staining for α-actinin was conducted to determine cell surface area. Atrial Natriuretic Peptide (ANP) and Brain Natriuretic Peptide (BNP) of hypertrophy markers were examined. Ang-II infusion was given to stimulate cardiac hypertrophy in mice. The cardiac function of mice was detected by echocardiography, and the pathological status of myocardial tissue was observed. ResultsThe surface of cardiomyocytes was enlarged by Ang-II, and ANP and BNP levels were increased. QL processing could save these changes. miR-382-5p was upregulated in Ang-II-treated NMVCs, and reducing miR-382-5p could further enhance the therapeutic effect of QL while elevating miR-382-5p weakened the protective effect of QL. QL could inhibit miR-382-5p expression to negatively regulate Activated Transcription Factor 3 (ATF3) expression. Enhancing ATF3 expression rescued miR-382-5p upregulation-mediated role in NMVCs. In addition, QL alleviated Ang-II-stimulated cardiac hypertrophy and cardiac dysfunction in mice. ConclusionQL may alleviate cardiac hypertrophy and cardiac dysfunction via the miR-382-5p/ATF3 axis.

Changes of Serum Angiotensin Peptides, Pro-Endothelin-1 Levels in Women One Year After Preeclampsia and their Association with Cardiovascular Risk Factors

Abstract Introduction 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. Materials and methods The current research examined 32 women one year after preeclampsia (mean age 25.3 ± 6.3 years) and control group of 20 women one year after normal pregnancy (mean age 25.6 ± 5.6 years). The enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of angiotensin II (AngII), angiotensin-(1-7) [Ang-(1-7)] and pro-endothelin-1 (Pro-ET-1). Results We found that at 1 year after delivery 38.46% of women who suffered PE have developed hypertension and 5.77% have developed diabetes mellitus. Women who had normal pregnancy developed neither hypertension, nor diabetes mellitus 1 year after delivery. Serum AngII levels in women one year after PE were statistically significantly lower than in women one year after normotensive pregnancy 0.9 (0.55÷1.7) vs. 2.3 pg/ml (2.0 ÷ 2.9) (KW = 20.849; p = 0.0001). Ang-(1-7) concentrations in women one year after PE were lower than in women one year after normal pregnancy, but not significantly 1.7 (0.3÷4.5) vs. 3.2 ng/ml (0.2÷8.0) (p>0.05). Levels of serum Pro-ET-1 in women one year after PE were statistically significantly higher than in women one year after normal pregnancy 322.65 (261.75÷391.85) vs. 248.7 pmol/L (231.05÷282.15) (KW = 6.639; p = 0.009). AngII showed correlation with AH grade (r = -0.33; 0.02), Ang-(1-7) (r = 0.27; 0.05), DBP (r = -0.28; p = 0.04), mean arterial pressure (r = -0.43; p = 0.002), pulse pressure (r = -0.28; p = 0.04), BMI (r = -0.30; p = 0.03), TC (r = -0.31; p = 0.03) and LDL (r = -0.30; p = 0.03). Pro-ET-1 correlated with age (r = 0.30; p = 0.03), mean arterial pressure (r = -0.25; p = 0.05) and pulse pressure (r = 0.41; p = 0.003). Conclusion Our data showed an association between key vasoactive peptides and major CVD risk factors in women one year after PE. We suggest that imbalance between AngII, Ang-(1-7) and Pro-ET-1 could have a potential imply on the vascular wall after PE, reflecting persistent microvascular and endothelial injury/dysfunction postpartum. Further studies are warranted to clarify these vasoactive peptides’ role in the ongoing vascular endothelial function after delivery and the pathogenic mechanisms determining development of CVD in previously PE women.

Abstract 11373: Suppression of Plasma Angiotensin II by GLP-1 in Humans is Independent of Changes in Plasma Angiotensinogen

Introduction: In humans, the natriuretic effect of GLP-1 depends on GLP-1 receptor interaction, is independent of changes in renal blood flow, renin, ANP, and aldosterone but is accompanied by suppression of angiotensin II (ANGII). The mechanism by which GLP-1 reduces ANGII independently of changes in renin is not clarified. Hypothesis: It was hypothesized that GLP-1 suppresses renin substrate, angiotensinogen, in plasma. Methods: To test this proposal, we measured arterial angiotensinogen concentration in biobanked plasma samples from healthy males during a 3-hour GLP-1 infusion that induced natriuresis (1). Samples were from a study with fixed sodium intake where eight healthy men were examined twice in random order during a 3-hour infusion of either GLP-1(1.5 pmol kg -1 min -1 ) or vehicle together with an intravenous infusion of 0.9% NaCl (750 mL/hour). Arterial plasma angiotensinogen was measured in plasma by dilution (1:200) and addition of excess exogenous human renin (Inst. Of Biological Standards UK). After prolonged incubation, ANGI was quantified by radioimmunoassay. Intraassay variation was 9-12%. Results: Arterial plasma angiotensinogen and renin levels decreased similarly and modestly (~15 and ~30%, respectively) after NaCl infusion during both studies whereas ANGII levels decreased significantly (~25%) only during GLP-1 infusion. Conclusions: Suppression of plasma angiotensinogen is less likely to account for GLP-1-mediated ANGII suppression in healthy young males. In perspective, GLP-1 could enhance pathways of ANGII degradation rather than inhibit its formation. 1. Asmar A et al. Extracellular fluid volume expansion uncovers a natriuretic action of GLP-1: a functional GLP-1-renal axis in man. J Clin Endocrinol Metab. 2019 Jul 1;104(7):2509-2519.

1652-P: Suppression of Plasma Angiotensin II by GLP-1 in Humans Is Independent of Changes in Plasma Angiotensinogen

In humans, the natriuretic effect of GLP-1 depends on GLP-1 receptor interaction, is independent of changes in renal blood flow, renin, ANP, and aldosterone but is accompanied by suppression of angiotensin II (ANGII). The mechanism by which GLP-1 reduces ANGII independently of changes in renin is not clarified. It was hypothesized that GLP-1 suppresses renin substrate, angiotensinogen, in plasma. To test this proposal, we measured arterial angiotensinogen concentration in biobanked plasma samples from healthy males during a 3-hour GLP-1 infusion that induced natriuresis (1). Samples were from a study with fixed sodium intake where eight healthy men were examined twice in random order during a 3-hour infusion of either GLP-1(1.5 pmol kg-1 min-1) or vehicle together with an intravenous infusion of 0.9% NaCl (750 mL/hour). Arterial plasma angiotensinogen was measured in plasma by dilution (1:200) and addition of excess exogenous human renin (Inst. of Biological Standards UK). After prolonged incubation, ANGI was quantified by radioimmunoassay. Intraassay variation was 9-12%. Arterial plasma angiotensinogen and renin levels decreased similarly and modestly (~15 and ~30%, respectively) after NaCl infusion during both studies whereas ANGII levels decreased significantly (~25%) only during GLP-1 infusion. Suppression of plasma angiotensinogen is less likely to account for GLP-1-mediated ANGII suppression in healthy young males. In perspective, GLP-1 could enhance pathways of ANGII degradation rather than inhibit its formation. 1. Asmar A et al. Extracellular fluid volume expansion uncovers a natriuretic action of GLP-1: a functional GLP-1-renal axis in man. J Clin Endocrinol Metab. 2019 Jul 1;104(7):2509-2519. Disclosure B.L.Jensen: None. A.Asmar: Research Support; Novo Nordisk A/S.

Non-Invasive Ultrasound Modulation of Solitary Tract Nucleus Exerts a Sustainable Antihypertensive Effect in Spontaneously Hypertensive Rats.

We applied the method of non-invasive ultrasound (US) neuromodulation to regulate blood pressure (BP) by stimulating the solitary tract nucleus (NTS) of spontaneously hypertensive rats (SHRs). The rats were exposed to US stimulation for 20 mins every day for two months. Morphology and function of the hypertensive target organs (heart and kidney) were then examined by echocardiography and immunohistochemical staining. C-fos immunofluorescence assays were used to evaluate neuronal activity in the US stimulated areas and to explore related neural pathways. Moreover, the effects of US stimulation on biochemical indicators angiotensinII (ANGII), aldosterone (Aldo), endothelin-1 (ET-1), atrial natriuretic factor (ANF), cortisol (Cor) in SHRs were detected. In addition, HE, TUNEL, and Nissl staining were performed to evaluate the safety of long-term transcranial US stimulation. After two months of US stimulation, systolic blood pressure (SBP) decreased from 170 ± 1.1 mmHg to 158 ± 1.8 mmHg, p < 0.01. What's more, US stimulation effectively inhibited the pathological process of target organs from both morphological and functional levels. With US stimulation, neuronal activities were also significantly enhanced in the NTS, ventrolateral periaqueductal gray (vlPAG), and the caudal ventrolateral medulla (CVLM) region. And US stimulation did not cause brain tissue damage. Meanwhile, the plasma levels of ANF, ANGII, Aldo, and Cor content were inhibited. US stimulation of the NTS could significantly lower BP in SHRs. Non-invasive transcranial US stimulation acting on the NTS might be a potential therapeutic intervention due to its efficacy and safety.

Patchouli alcohol against renal fibrosis of spontaneously hypertensive rats via Ras/Raf-1/ERK1/2 signalling pathway.

The present study was designed to obverse the protection of patchouli alcohol (PA) ameliorates hypertensive nephropathy in spontaneously hypertensive rats (SHR) and reveals potential mechanism. Briefly, the adult spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats (half male and half female) were intragastric gavaged or not with PA (80, 40 and 20 mg/kg) for 8 weeks. Body weight, blood pressure (BP), renal weight, renal function and renal morphology were measured. Further, western blotting and immunohistochemical analysis were used to study the underlying mechanism. Compared with the WKY group, plasmatic levels of renin, angiotensin II (Ang-II), transforming growth factor beta 1(TGF-β1), plasminogen activator inhibitor-1(PAI-1), creatinine (Cr), blood urea nitrogen (BUN), renal index, mRNA levels of ERK1/2 and α-SMA were significantly increased in SHR. Histology results showed that renal tubular injury and tubulointerstitial fibrosis occurred in SHR. After administration, SBP of captopril group decreased at each week after administration, especially at 3, 5, 6 7 and 8 weeks (P < 0.05 or P < 0.01). There is no significant effect was assessed in the olive oil group. Decreased plasma Cr, Renin, Ang-II, TGF-β1, PAI-1, SCFAs and Renin, TGF-β1, PAI-1 in renal tissues were observed significantly in captopril (P <0.05 or P < 0.01). Plasma BUN, Ang-II, TGF-β1 and PAI-1 in renal tissues decreased in the olive oil group significantly (P <0.05 or P < 0.01). PA (80, 40 and 20 mg/kg) lowered BP and plasmatic levels of Renin, Ang-II, TGF-β1 and PAI-1. Treatment with PA (40, 20 mg/kg) decreased levels of Cr, BUN and suppressed of activation of pro-fibrosis cytokines including TGF-β1 in kidney. There is no ameliorative change in the olive oil group and the captopril group (P > 0.05) while PA treatment alleviated renal tubular injury and produced dramatic collagen fibre area reductions in mesangial membrane, basement membrane, and renal interstitium obviously (P < 0.05 or P < 0.01). Treatment of SHR with PA-inhibited MFB activation and downregulated mRNA of α-SMA. Treatment with PA suppressed excessive production of the extracellular matrix (ECM) via decreasing Col I, III and FN, downregulating mRNA of tissue inhibitor of TIMP-1 along with upregulating mRNA of MMP-9. The expression of Col III and MMP-9 mRNA-reduced in the captopril group (P < 0.05). In addition, the expression of ERK1/2 and pERK1/2 also reduced in the captopril group significantly (P < 0.05 or P < 0.01). Treatment with PA (20 mg/kg) downregulated proteins expression of Raf-1, ERK1/2 and pERK1/2 and mRNA expression of Ras, Raf-1 and ERK1/2. Overall, PA restored normal BP, alleviated renal dysfunction and renal fibrosis, possibly by suppressing Ang II and TGF-β1-mediated Ras/Raf-1/ERK1/2 signalling pathway.

Evidence for Angiotensin II as a Naturally Existing Suppressor for the Guanylyl Cyclase A Receptor and Cyclic GMP Generation.

The natriuretic peptide system (NPS) and renin-angiotensin-aldosterone system (RAAS) function oppositely at multiple levels. While it has long been suspected that angiotensin II (ANGII) may directly suppress NPS activity, no clear evidence to date supports this notion. This study was designed to systematically investigate ANGII-NPS interaction in humans, in vivo, and in vitro. Circulating atrial, b-type, and c-type natriuretic peptides (ANP, BNP, CNP), cyclic guanosine monophosphate (cGMP), and ANGII were simultaneously investigated in 128 human subjects. Prompted hypothesis was validated in vivo to determine the influence of ANGII on ANP actions. The underlying mechanisms were further explored via in vitro approaches. In humans, ANGII demonstrated an inverse relationship with ANP, BNP, and cGMP. In regression models predicting cGMP, adding ANGII levels and the interaction term between ANGII and natriuretic peptides increased the predictive accuracy of the base models constructed with either ANP or BNP, but not CNP. Importantly, stratified correlation analysis further revealed a positive association between cGMP and ANP or BNP only in subjects with low, but not high, ANGII levels. In rats, co-infusion of ANGII even at a physiological dose attenuated cGMP generation mediated by ANP infusion. In vitro, we found the suppressive effect of ANGII on ANP-stimulated cGMP requires the presence of ANGII type-1 (AT1) receptor and mechanistically involves protein kinase C (PKC), as this suppression can be substantially rescued by either valsartan (AT1 blocker) or Go6983 (PKC inhibitor). Using surface plasmon resonance (SPR), we showed ANGII has low binding affinity to the guanylyl cyclase A (GC-A) receptor compared to ANP or BNP. Our study reveals ANGII is a natural suppressor for the cGMP-generating action of GC-A via AT1/PKC dependent manner and highlights the importance of dual-targeting RAAS and NPS in maximizing beneficial properties of natriuretic peptides in cardiovascular protection.

Antihypertensive effects of Pleurospermum lindleyanum aqueous extract in spontaneously hypertensive rats.

Pleurospermum lindleyanum (Lipsky) B. Fedtsch is a perennial herb classified in the Apiaceae family, genus Pleurospermum, chiefly native to the Taxkorgan County, Xinjiang, China. In the Xinjiang Province, it is a well-known ethnic traditional herb, often addressed by its tribal name, Kurumuti. It grows in harsh conditions over 4000m above sea level, such as the Pamirs plateau. It is rich in flavonoids, coumarins, terpenoids, essential oil, substances that have been widely applied in the prevention and treatment of hypertension, diabetes, coronary heart disease, and cerebral thrombosis by local Tajik residents. The present study aimed to evaluate the antihypertensive effects of the Pleurospermum Lindleyanum aqueous extract (PLAE) in spontaneously hypertensive rats (SHRs). The Pleurospermum lindleyanum was collected from the Taxkorgan Tajik Autonomous County, Xinjiang, China. The main chemical composition of PLAE was identified using the ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). SHRs were treated by gavage with PLAE (equivalent to Pleurospermum lindleyanum 5 or 10g/kg/day) for 6 weeks, using Captopril (10mg/kg/day) as positive control. The systolic blood pressure (SBP), renal and cardiac morphology, plasma levels of angiotensin-converting enzyme (ACE), aldosterone (ALD), angiotensinⅡ (AngⅡ), superoxide dismutase (SOD), endothelin-1 (ET-1) and nitric oxide (NO) were measured. A total of 30 compounds were identified in PLAE. PLAE significantly attenuated the SBP of SHRs. The effects began after 3 weeks of administration and then became steady and long-lasting. Its potential mechanisms may be associated with the protective effects on renal and cardiac injury caused by hypertension, the decrease of plasma vasoconstrictors, such as ACE, ALD, AngⅡ, and ET-1 levels, the maintenance of NO/ET balance, the increase in plasma NO levels and SOD activity, thereby reducing oxidative stress. Pleurospermum lindleyanum can be suggested as a novel antihypertensive ethnic traditional herb, which lays the foundation for researching safe and effective antihypertensive herbal medicines.

Pulmonary Artery Denervation Inhibits Left Stellate Ganglion Stimulation-Induced Ventricular Arrhythmias Originating From the RVOT

BackgroundElectrical stimulation of the left stellate ganglion (LSG) can evoke ventricular arrhythmias (VAs) that originate from the right ventricular outflow tract (RVOT). The involvement of pulmonary artery innervation is unclear. ObjectivesThis study investigated the effects of selective pulmonary artery denervation (PADN) on blood pressure (BP), sympathetic activity, ventricular effective refractory period (ERP), and the incidence of VAs induced by LSG stimulation in canines. MethodsRadiofrequency ablation with basic anesthetic monitoring was used to induce PADN in canines. In Protocol 1 (n = 11), heart rate variability, serum norepinephrine and angiotensin-II levels, BP changes and ventricular ERP in response to LSG stimulation were measured before and after PADN. In Protocol 2 (n = 8), the incidence of VAs induced by LSG stimulation was calculated before and after PADN in a canine model of complete atrioventricular block. In addition, sympathetic nerves in the excised pulmonary arteries were immunohistochemically stained with tyrosine hydroxylase. ResultsThe low-frequency components of heart rate variability, serum norepinephrine and angiotensin-II levels were remarkably decreased post-PADN. Systolic BP elevation and RVOT ERP shortening induced by LSG stimulation were mitigated by PADN. The number of RVOT-premature ventricular contractions as well as RVOT tachycardia episodes and duration induced by LSG stimulation were significantly reduced after PADN. In addition, a large number of tyrosine hydroxylase-immunoreactive nerve fibers were located in the anterior wall of the pulmonary artery. ConclusionsPADN ameliorated RVOT ERP shortening, and RVOT-VAs induced by LSG stimulation by inhibiting cardiac sympathetic nerve activity.

Improvement in Blood Pressure After Intermittent Fasting in Hipertension: Could Renin-Angiotensin System and Autonomic Nervous System Have a Role?

Although it has been reported that the intermittent fasting (IF) diet has positive effects on heart health and improvement in blood pressure, it has not been sufficiently clarified how it could have these positive effects yet. We aimed to evaluate the effects of IF on the autonomic nervous system (ANS) and renin-angiotensin system (RAS), which are closely related to blood pressure. Seventy-two hypertensive patients were included in the study, and the data of 58 patients were used. All the participants fasted for about 15-16 hours for 30 days. Participants were evaluated with 24-hour ambulatory blood pressure monitoring and Holter electrocardiography before and after IF; also, 5 ml venous blood samples were taken for assessment of Serum angiotensin I (Ang-I) and angiotensin II (Ang-II) levels and angiotensin-converting enzyme (ACE) activity. For data analysis, the p-value <0.05 was accepted as significant. Compared to pre-IF, a significant decrease was observed in the patients' blood pressures in post-IF. An increase in high-frequency (HF) power and the mean root square of the sum of squares of differences between adjacent NN intervals (RMSSD) were observed after the IF protocol (p=0.039, p=0.043). Ang-II and ACE activity were lower in patients after IF (p=0.034, p=0.004), and decreasing Ang-II levels were determined as predictive factors for improvement of the blood pressure, like the increase in HF power and RMSSD. The present findings of our study demonstrated an improvement in blood pressure and the relationship of blood pressure with positive outcomes, including HRV, ACE activity, and Ang-II levels after the IF protocol.

Relationship Among Surgical Fibroid Removal, Blood Pressure, and Biomarkers of Renin-Angiotensin-Aldosterone System Activation.

Fibroids are common benign neoplasms in women and have recently been associated with cardiometabolic risk factors including hypertension. The objective of this study is to determine whether fibroid removal is associated with lower blood pressure (BP). We performed a single-center IRB-approved retrospective chart review of patients undergoing hysterectomy/myomectomy for fibroids and other benign gynecological surgical procedures from January 2016 to December 2019, and a prospective cohort study of patients undergoing hysterectomy/myomectomy for fibroids from August 2021 to April 2022. We measured demographic factors, preoperative/postoperative BP on day of surgery and at postoperative visit. In our prospective cohort, to evaluate for alterations in the renin-angiotensin-aldosterone system (RAAS) induced by fibroid removal, we measured serum angiotensin-II (Ang-II) and angiotensin converting enzyme (ACE) levels pre- and post-operatively. In our retrospective study (n = 294; mean age 41.9 ± 10.6, 43.5% Black, 50% with fibroids), we found that compared to patients without fibroids, patients with fibroids had significantly elevated systolic BP (SBP) (pre-op: p = 0.0005; post-op: p = 0.02), although this did not hold after adjusting for covariates. Fibroid removal was associated with a marginally albeit not statistically significant decrease in SBP (p = 0.062). In our prospective study (n = 11), there was a significant decrease in SBP following fibroid removal, but no change in diastolic BP (p = 0.019, p = 0.18, respectively). Serum levels of Ang-II and ACE were not significantly altered following surgical fibroid removal (p = 0.72, p = 0.81, respectively). Altogether, these findings suggest that fibroids are not independently associated with BP or RAAS activation, but do suggest that fibroid removal may be associated with a small drop in SBP.

The alkaloids of Corydalis hendersonii Hemsl. contribute to the cardioprotective effect against ischemic injury in mice by attenuating cardiomyocyte apoptosis via p38 MAPK signaling pathway

BackgroundThere is a characteristic Tibetan folk medicine in China named Corydalis hendersonii Hemsl. (CH) has been used for treatment of cardiovascular related diseases, called “plethora” in Tibetan medicine. Previous studies demonstrated that ethanol extract of CH showed anti-acute myocardial infarction (AMI) effect through inhibiting fibrosis and inflammation. Rich alkaloids fraction (RAF) is isolated from CH, but whether RAF possessing an equivalent effect with the CH ethanol extract and by which mechanism it protects against AMI has not yet reported. The paper aimed to study the potential role of RAF on myocardial injured mice and its underlying mechanism.Materials and methodsLiquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) was used to analyze the chemical profile and isolate pure compounds. The ligation of left anterior descending (LAD) of coronary artery in mice was used to evaluate the in vivo anti-AMI effect, by dividing into eight groups: Sham, Model, Fosinopril (10 mg/kg, i.g.), total extract (TE, 400 mg/kg, i.g.), poor alkaloids fraction (PAF, 300 mg/kg, i.g.), and RAF (25, 50, and 100 mg/kg, respectively, i.g.) groups. Echocardiography was used to evaluate mice heart function through the index of left ventricular end-systolic diameter (LVEDs), left ventricular end-diastolic diameter (LVEDd), fractional shortening (FS) and ejection fraction (EF). We detected the lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) in the serum and the plasma level of angiotensin II (AngII). The apoptosis of mice myocardial tissue was verified by TUNEL assay. The expression of p38 mitogen-activated protein kinases (p38 MAPK), Bcl-2 and Bcl-2-associated X protein (Bax) were detected through immunofluorescence staining, qRT-PCR and western blot in mice heart tissue and H9c2 cells.ResultsEchocardiography data indicated that the values of LVEDd and LVEDs were reduced and the values of FS and EF were improved by TE and RAF significantly. RAF also decreased the levels of LDH, CK-MB and AngII and significantly inhibited inflammatory cells in the marginal zone of myocardial infarction. The TUNEL assay results showed that RAF significantly attenuated cell apoptosis. Immunofluorescence and qRT-PCR assay showed that RAF inhibited p38 MAPK, Bax, and Bcl-2 proteins in mice myocardium. Western blot results validated that the expressions of key proteins were inhibited by RAF. Also, the apoptotic cells and apoptosis-related proteins were dramatically reduced by RAF in vivo and in vitro. Besides, RAF and PAF were analyzed by LCMS-IT-TOF to identify the main compounds and to demonstrate the difference between them. The results showed that a total of 14 alkaloids were identified, which indicated that the isoquinoline alkaloids were the main ingredients in RAF may contributing to the cardioprotective effect in mice.ConclusionsRAF improves cardiac function by inhibiting apoptosis via p38 MAPK signaling pathway, and RAF contributes to the effect against myocardial ischemic injury of TE in mice, which provides a substantial reference for the clinical application against ischemia heart disease and quality control of CH.Graphical

Impacts of Cold-Stress Stimulation On Mice Pregnancy.

Animals exposed to cold stress develop hypertension; however, the effects of cold-induced hypertension on pregnancy remain unclear. We therefore, aimed to investigate the impacts of cold-stress stimulation on mice pregnancy. Four groups of mice were used in the study: non-pregnant control group (NN), non-pregnant cold-stress group (NC), pregnant control group (PN) and pregnant cold-stress group (PC). control groups were kept at 25℃, and the cold-stress groups were kept in a room for cold-stress stimulation (4 ± 2℃) for 4 hours (then back to 25℃) every day from the 1st to the 18th day. The blood pressure of the PC was the highest among the four groups, and the hypertensive percentage of the PC was significantly increased. However, plasma angiotensinⅡ levels of the PC were the lowest. The weights of the foetus and placenta in the PC were significantly decreased compared to the PN. More apparent changes in kidneys and placenta were observed in the PC compared to the PN. The blood pressure of pregnant mice showed no difference between the PN and PC groups 50 days after delivery. Intermittent cold-stress stimulation had significantly adverse effects on the pregnant mice, leading to maternal hypertension, renal and placental lesions, body weight and placenta reduction in offspring. The study results may offer a non-invasive method to establish an animal model of hypertensive disorders in pregnancy. Cold-stress stimulation may be one of the inducible factors of pregnancy-induced hypertension.Cold-stress stimulation may be one of the inducible factors of pregnancy-induced hypertension.

Enalaprilat as a new means of preventing the development of retinopathy of prematurity.

In a rat model of experimental retinopathy of prematurity (ROP), the safety of enalaprilat and its effect on the level of angiotensin-converting enzyme (ACE) and angiotensin-II (AT-II) in the vitreous body and retina were investigated. The study was performed on 136 newborn Wistar rat pups divided into 2 groups: group A - experimental (animals with ROP, n=64) and group B - control (n=72). Each group was further divided into 2 subgroups: A0 and B0 (n=32 and n=36, respectively) - animals that did not receive injections of enalaprilat, and A1 and B1 (n=32 and n=36, respectively) - animals treated with daily intraperitoneal (i.p.) injections of enalaprilat (0.6 mg/kg of body weight). This treatment started on day 2 and lasted either to day 7 or to day 14 in accordance with the therapeutic scheme. Animals were taken out of the experiment on day 7 and day 14. In samples of the vitreous body and retina, the content of ACE and AT-II was determined by enzyme immunoassay. On day 7 in subgroups A1 and B1 the levels of ACE and AT-II in the vitreous did not differ, while on day 14 were lower than in subgroups A0 and B0, respectively. Changes in the parameters studied in the retina were somewhat different from those found in the vitreous body. On the seventh day, the level of ACE in the retina of animals of subgroup B1 did not differ significantly from subgroup B0, and in subgroup A1 it was increased compared to subgroup A0. On day 14, its significant decrease was noted in subgroups A1 and B1 as compared with subgroups A0 and B0. At the same time, the level of AT-II in the retina of rat pups of subgroup B1 was lower than in subgroup B0, both on day 7 and day 14. On day 7, the concentration of AT-II, as well as the concentration of ACE, increased in subgroup A1 as compared to subgroup A0. On day 14, this parameter in subgroup A1 was significantly lower as compared to subgroup A0, but significantly higher than in subgroup B1. It should be noted that i.p. injections of enalaprilat, increased a death rate of animals of both groups. The use of enalaprilat, starting from the preclinical period of the ROP development, led to a decrease in the activity of the renin-angiotensin system (RAS) in ROP animals at the onset of retinopathy in the experimental model used. This opens up prospects for considering enalaprilat as a means of preventing the development of this pathology; however, the recognized high toxicity of the drug requires further studies and correction of the timing of its administration and dosage in order to achieve a balance of efficacy and safety of use in order to prevent the development of ROP in children.