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Physiological Reviews Jan 2018The renin-angiotensin system (RAS) is a key player in the control of the cardiovascular system and hydroelectrolyte balance, with an influence on organs and functions... (Review)
Review
The renin-angiotensin system (RAS) is a key player in the control of the cardiovascular system and hydroelectrolyte balance, with an influence on organs and functions throughout the body. The classical view of this system saw it as a sequence of many enzymatic steps that culminate in the production of a single biologically active metabolite, the octapeptide angiotensin (ANG) II, by the angiotensin converting enzyme (ACE). The past two decades have revealed new functions for some of the intermediate products, beyond their roles as substrates along the classical route. They may be processed in alternative ways by enzymes such as the ACE homolog ACE2. One effect is to establish a second axis through ACE2/ANG-(1-7)/MAS, whose end point is the metabolite ANG-(1-7). ACE2 and other enzymes can form ANG-(1-7) directly or indirectly from either the decapeptide ANG I or from ANG II. In many cases, this second axis appears to counteract or modulate the effects of the classical axis. ANG-(1-7) itself acts on the receptor MAS to influence a range of mechanisms in the heart, kidney, brain, and other tissues. This review highlights the current knowledge about the roles of ANG-(1-7) in physiology and disease, with particular emphasis on the brain.
Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Brain; Humans; Peptide Fragments; Peptidyl-Dipeptidase A; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Renin-Angiotensin System; Signal Transduction
PubMed: 29351514
DOI: 10.1152/physrev.00023.2016 -
Cell Metabolism Jun 2018Fibroblast growth factor 21 (FGF21) is a metabolic hormone with pleiotropic effects on glucose and lipid metabolism and insulin sensitivity. However, the role of FGF21...
Fibroblast growth factor 21 (FGF21) is a metabolic hormone with pleiotropic effects on glucose and lipid metabolism and insulin sensitivity. However, the role of FGF21 in hypertension remains elusive. Here we show that FGF21 deficiency significantly exacerbates angiotensin II-induced hypertension and vascular dysfunction, whereas such negative effects are reversed by replenishment of FGF21. Mechanistically, FGF21 acts on adipocytes and renal cells to promote induction of angiotensin-converting enzyme 2 (ACE2), which in turn converts angiotensin II to angiotensin-(1-7), then inhibits hypertension and reverses vascular damage. In addition, ACE2 deficiency strikingly abrogates these beneficial effects of FGF21 in mice, including alleviation of angiotensin II-associated hypertension and vascular damage. Otherwise, pharmaceutical inhibition of angiotensin-(1-7) attenuates the protective effect of FGF21 on angiotensin II-induced vascular dysfunction, but not on hypertension. Thus, FGF21 protects against angiotensin II-induced hypertension and vascular impairment by activation of the ACE2/angiotensin-(1-7) axis via fine-tuning the multi-organ crosstalk between liver, adipose tissue, kidney, and blood vessels.
Topics: Adipose Tissue; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Blood Pressure; Cardiovascular System; Fibroblast Growth Factors; Hypertension; Kidney; Loss of Function Mutation; Mice; Mice, Inbred C57BL; Mice, Knockout; Peptide Fragments; Peptidyl-Dipeptidase A
PubMed: 29706566
DOI: 10.1016/j.cmet.2018.04.002 -
Hypertension (Dallas, Tex. : 1979) May 2024The renin-angiotensin system is the most important peptide hormone system in the regulation of cardiovascular homeostasis. Its classical arm consists of the enzymes,... (Review)
Review
The renin-angiotensin system is the most important peptide hormone system in the regulation of cardiovascular homeostasis. Its classical arm consists of the enzymes, renin, and angiotensin-converting enzyme, generating angiotensin II from angiotensinogen, which activates its AT receptor, thereby increasing blood pressure, retaining salt and water, and inducing cardiovascular hypertrophy and fibrosis. However, angiotensin II can also activate a second receptor, the AT receptor. Moreover, the removal of the C-terminal phenylalanine from angiotensin II by ACE2 (angiotensin-converting enzyme 2) yields angiotensin-(1-7), and this peptide interacts with its receptor Mas. When the aminoterminal Asp of angiotensin-(1-7) is decarboxylated, alamandine is generated, which activates the Mas-related G-protein-coupled receptor D, MrgD (Mas-related G-protein-coupled receptor type D). Since Mas, MrgD, and the AT receptor have opposing effects to the classical AT receptor, they and the enzymes and peptides activating them are called the alternative or protective arm of the renin-angiotensin system. This review will cover the historical aspects and the current standing of this recent addition to the biology of the renin-angiotensin system.
Topics: Angiotensin I; Angiotensin II; Peptide Fragments; Peptides; Peptidyl-Dipeptidase A; Receptors, G-Protein-Coupled; Renin; Renin-Angiotensin System; Humans
PubMed: 38362781
DOI: 10.1161/HYPERTENSIONAHA.123.21364 -
Methods in Molecular Biology (Clifton,... 2017The renin-angiotensin system (RAS) is a complex circulating and tissue-based system. There are multiple pathways for the formation and degradation of peptides. In order... (Review)
Review
The renin-angiotensin system (RAS) is a complex circulating and tissue-based system. There are multiple pathways for the formation and degradation of peptides. In order to understand the functions of the system, characterization of angiotensin peptides (products and substrates) is important. Radioimmunoassays with the requisite specificity and sensitivity have been developed to allow for the characterization and quantification of circulating and tissue angiotensins. Here, we describe the appropriate methods for collecting the tissue and blood, the extractions steps required to partially purify and remove larger molecular weight-interfering proteins from tissue and plasma, and the radioimmunoassay of three of the peptides of this system (Ang I, Ang II, and Ang-(1-7)), as well as the verification of immunoreactive identity for Ang II and Ang-(1-7) by combined high-performance liquid chromatography-RIA analysis.
Topics: Angiotensin I; Angiotensin II; Animals; Chromatography, High Pressure Liquid; Humans; Peptide Fragments; Radioimmunoassay; Renin-Angiotensin System
PubMed: 28116709
DOI: 10.1007/978-1-4939-6625-7_7 -
American Journal of Hypertension Nov 2019Despite decades of research and numerous treatment approaches, hypertension and cardiovascular disease remain leading global public health problems. A major contributor... (Review)
Review
Despite decades of research and numerous treatment approaches, hypertension and cardiovascular disease remain leading global public health problems. A major contributor to regulation of blood pressure, and the development of hypertension, is the renin-angiotensin system. Of particular concern, uncontrolled activation of angiotensin II contributes to hypertension and associated cardiovascular risk, with antihypertensive therapies currently available to block the formation and deleterious actions of this hormone. More recently, angiotensin-(1-7) has emerged as a biologically active intermediate of the vasodilatory arm of the renin-angiotensin system. This hormone antagonizes angiotensin II actions as well as offers antihypertensive, antihypertrophic, antiatherogenic, antiarrhythmogenic, antifibrotic and antithrombotic properties. Angiotensin-(1-7) elicits beneficial cardiovascular actions through mas G protein-coupled receptors, which are found in numerous tissues pivotal to control of blood pressure including the brain, heart, kidneys, and vasculature. Despite accumulating evidence for favorable effects of angiotensin-(1-7) in animal models, there is a paucity of clinical studies and pharmacokinetic limitations, thus limiting the development of therapeutic agents to better understand cardiovascular actions of this vasodilatory peptide hormone in humans. This review highlights current knowledge on the role of angiotensin-(1-7) in cardiovascular control, with an emphasis on significant animal, human, and therapeutic research efforts.
Topics: Angiotensin I; Animals; Antihypertensive Agents; Blood Pressure; Cardiovascular System; Humans; Hypertension; Peptide Fragments; Renin-Angiotensin System; Signal Transduction; Vasodilator Agents
PubMed: 31602467
DOI: 10.1093/ajh/hpz146 -
Peptides Jun 2022Angiotensin converting enzyme (ACE) is well known for its role producing the vasoconstrictor angiotensin II and ACE inhibitors are commonly used for treating...
Angiotensin converting enzyme (ACE) is well known for its role producing the vasoconstrictor angiotensin II and ACE inhibitors are commonly used for treating hypertension and cardiovascular disease. However, ACE has many different substrates besides angiotensin I and plays a role in many different physiologic processes. Here, we discuss the role of ACE in the immune response. Several studies in mice indicate that increased expression of ACE by macrophages or neutrophils enhances the ability of these cells to respond to immune challenges such as infection, neoplasm, Alzheimer's disease, and atherosclerosis. Increased expression of ACE induces increased oxidative metabolism with an increase in cell content of ATP. In contrast, ACE inhibitors have the opposite effect, and in both humans and mice, administration of ACE inhibitors reduces the ability of neutrophils to kill bacteria. Understanding how ACE affects the immune response may provide a means to increase immunity in a variety of chronic conditions now not treated through immune manipulation.
Topics: Angiotensin I; Angiotensin-Converting Enzyme Inhibitors; Animals; Hypertension; Macrophages; Mice; Peptidyl-Dipeptidase A
PubMed: 35182689
DOI: 10.1016/j.peptides.2022.170769 -
Hypertension (Dallas, Tex. : 1979) Jan 2018
Topics: Angiotensin I; Angiotensin II; Humans; Muscle, Smooth, Vascular; Peptide Fragments
PubMed: 29203630
DOI: 10.1161/HYPERTENSIONAHA.117.10406 -
Critical Care (London, England) Feb 2020In patients with vasodilatory shock, plasma concentrations of angiotensin I (ANG I) and II (ANG II) and their ratio may reflect differences in the response to severe...
BACKGROUND
In patients with vasodilatory shock, plasma concentrations of angiotensin I (ANG I) and II (ANG II) and their ratio may reflect differences in the response to severe vasodilation, provide novel insights into its biology, and predict clinical outcomes. The objective of these protocol prespecified and subsequent post hoc analyses was to assess the epidemiology and outcome associations of plasma ANG I and ANG II levels and their ratio in patients with catecholamine-resistant vasodilatory shock (CRVS) enrolled in the Angiotensin II for the Treatment of High-Output Shock (ATHOS-3) study.
METHODS
We measured ANG I and ANG II levels at baseline, calculated their ratio, and compared these results to values from healthy volunteers (controls). We dichotomized patients according to the median ANG I/II ratio (1.63) and compared demographics, clinical characteristics, and clinical outcomes. We constructed a Cox proportional hazards model to test the independent association of ANG I, ANG II, and their ratio with clinical outcomes.
RESULTS
Median baseline ANG I level (253 pg/mL [interquartile range (IQR) 72.30-676.00 pg/mL] vs 42 pg/mL [IQR 30.46-87.34 pg/mL] in controls; P < 0.0001) and median ANG I/II ratio (1.63 [IQR 0.98-5.25] vs 0.4 [IQR 0.28-0.64] in controls; P < 0.0001) were elevated, whereas median ANG II levels were similar (84 pg/mL [IQR 23.85-299.50 pg/mL] vs 97 pg/mL [IQR 35.27-181.01 pg/mL] in controls; P = 0.9895). At baseline, patients with a ratio above the median (≥1.63) had higher ANG I levels (P < 0.0001), lower ANG II levels (P < 0.0001), higher albumin concentrations (P = 0.007), and greater incidence of recent (within 1 week) exposure to angiotensin-converting enzyme inhibitors (P < 0.00001), and they received a higher norepinephrine-equivalent dose (P = 0.003). In the placebo group, a baseline ANG I/II ratio <1.63 was associated with improved survival (hazard ratio 0.56; 95% confidence interval 0.36-0.88; P = 0.01) on unadjusted analyses.
CONCLUSIONS
Patients with CRVS have elevated ANG I levels and ANG I/II ratios compared with healthy controls. In such patients, a high ANG I/II ratio is associated with greater norepinephrine requirements and is an independent predictor of mortality, thus providing a biological rationale for interventions aimed at its correction.
TRIAL REGISTRATION
ClinicalTrials.gov identifier NCT02338843. Registered 14 January 2015.
Topics: Angiotensin I; Angiotensin II; Catecholamines; Female; Humans; Male; Shock
PubMed: 32028998
DOI: 10.1186/s13054-020-2733-x -
Scientific Reports Nov 2022SARS-CoV-2 gains cell entry via angiotensin-converting enzyme (ACE) 2, a membrane-bound enzyme of the "alternative" (alt) renin-angiotensin system (RAS). ACE2...
SARS-CoV-2 gains cell entry via angiotensin-converting enzyme (ACE) 2, a membrane-bound enzyme of the "alternative" (alt) renin-angiotensin system (RAS). ACE2 counteracts angiotensin II by converting it to potentially protective angiotensin 1-7. Using mass spectrometry, we assessed key metabolites of the classical RAS (angiotensins I-II) and alt-RAS (angiotensins 1-7 and 1-5) pathways as well as ACE and ACE2 concentrations in 159 patients hospitalized with COVID-19, stratified by disease severity (severe, n = 76; non-severe: n = 83). Plasma renin activity (PRA-S) was calculated as the sum of RAS metabolites. We estimated ACE activity using the angiotensin II:I ratio (ACE-S) and estimated systemic alt-RAS activation using the ratio of alt-RAS axis metabolites to PRA-S (ALT-S). We applied mixed linear models to assess how PRA-S and ACE/ACE2 concentrations affected ALT-S, ACE-S, and angiotensins II and 1-7. Median angiotensin I and II levels were higher with severe versus non-severe COVID-19 (angiotensin I: 86 versus 30 pmol/L, p < 0.01; angiotensin II: 114 versus 58 pmol/L, p < 0.05), demonstrating activation of classical RAS. The difference disappeared with analysis limited to patients not taking a RAS inhibitor (angiotensin I: 40 versus 31 pmol/L, p = 0.251; angiotensin II: 76 versus 99 pmol/L, p = 0.833). ALT-S in severe COVID-19 increased with time (days 1-6: 0.12; days 11-16: 0.22) and correlated with ACE2 concentration (r = 0.831). ACE-S was lower in severe versus non-severe COVID-19 (1.6 versus 2.6; p < 0.001), but ACE concentrations were similar between groups and correlated weakly with ACE-S (r = 0.232). ACE2 and ACE-S trajectories in severe COVID-19, however, did not differ between survivors and non-survivors. Overall RAS alteration in severe COVID-19 resembled severity of disease-matched patients with influenza. In mixed linear models, renin activity most strongly predicted angiotensin II and 1-7 levels. ACE2 also predicted angiotensin 1-7 levels and ALT-S. No single factor or the combined model, however, could fully explain ACE-S. ACE2 and ACE-S trajectories in severe COVID-19 did not differ between survivors and non-survivors. In conclusion, angiotensin II was elevated in severe COVID-19 but was markedly influenced by RAS inhibitors and driven by overall RAS activation. ACE-S was significantly lower with severe COVID-19 and did not correlate with ACE concentrations. A shift to the alt-RAS axis because of increased ACE2 could partially explain the relative reduction in angiotensin II levels.
Topics: Humans; Angiotensin-Converting Enzyme 2; Renin-Angiotensin System; Angiotensin I; COVID-19; Angiotensin II; SARS-CoV-2; Renin; Peptide Hormones; Antihypertensive Agents
PubMed: 36418458
DOI: 10.1038/s41598-022-24628-1 -
Nature Reviews. Cardiology Jul 2014The renin-angiotensin system (RAS) has pivotal roles in the regulation of normal physiology and the pathogenesis of cardiovascular disease. Angiotensin-converting enzyme... (Review)
Review
The renin-angiotensin system (RAS) has pivotal roles in the regulation of normal physiology and the pathogenesis of cardiovascular disease. Angiotensin-converting enzyme (ACE) 2, and its product angiotensin 1-7, are thought to have counteracting effects against the adverse actions of other, better known and understood, members of the RAS. The physiological and pathological importance of ACE2 and angiotensin 1-7 in the cardiovascular system are not completely understood, but numerous experimental studies have indicated that these components have protective effects in the heart and blood vessels. Here, we provide an overview on the basic properties of ACE2 and angiotensin 1-7 and a summary of the evidence from experimental and clinical studies of various pathological conditions, such as hypertension, atherosclerosis, myocardial remodelling, heart failure, ischaemic stroke, and diabetes mellitus. ACE2-mediated catabolism of angiotensin II is likely to have a major role in cardiovascular protection, whereas the relevant functions and signalling mechanisms of actions induced by angiotensin 1-7 have not been conclusively determined. The ACE2-angiotensin 1-7 pathway, however, might provide a useful therapeutic target for the treatment of cardiovascular disease, especially in patients with overactive RAS.
Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Angiotensin-Converting Enzyme Inhibitors; Biomarkers; Cardiovascular Agents; Cardiovascular Diseases; Humans; Peptide Fragments; Peptidyl-Dipeptidase A
PubMed: 24776703
DOI: 10.1038/nrcardio.2014.59