Search

Aortic aneurysm (AA) is an aortic disease with a high mortality rate, and other than surgery no effective preventive or therapeutic treatment have been developed. The renin–angiotensin system (RAS) is an important endocrine system that regulates vascular health. The ACE2/Ang‐(1–7)/MasR axis can antagonize the adverse effects of the activation of the ACE/Ang II/AT1R axis on vascular dysfunction, atherosclerosis, and the development of aneurysms, thus providing an important therapeutic target for the prevention and treatment of AA. However, products targeting the Ang‐(1–7)/MasR pathway still lack clinical validation. This review will outline the epidemiology of AA, including thoracic, abdominal, and thoracoabdominal AA, as well as current diagnostic and treatment strategies. Due to the highest incidence and most extensive research on abdominal AA (AAA), we will focus on AAA to explain the role of the RAS in its development, the protective function of Ang‐(1–7)/MasR, and the mechanisms involved. We will also describe the roles of agonists and antagonists, suggest improvements in engineering and drug delivery, and provide evidence for Ang‐(1–7)/MasR's clinical potential, discussing risks and solutions for clinical use. This study will enhance our understanding of AA and offer new possibilities and promising targets for therapeutic intervention. [ABSTRACT FROM AUTHOR]

The renin‐angiotensin system (RAS) is an endocrine system composed of two main axes: the classical and the counterregulatory, very often displaying opposing effects. The classical axis, primarily mediated by angiotensin receptors type 1 (AT1R), is linked to obesity‐associated metabolic effects. On the other hand, the counterregulatory axis appears to exert antiobesity effects through the activation of two receptors, the G protein‐coupled receptor (MasR) and Mas‐related receptor type D (MrgD). The local RAS in adipose organ has prompted extensive research into white adipose tissue and brown adipose tissue (BAT), with a key role in regulating the cellular and metabolic plasticity of these tissues. The MasR activation favors the brown plasticity signature in the adipose organ by improve the thermogenesis, adipogenesis, and lipolysis, decrease the inflammatory state, and overall energy homeostasis. The MrgD metabolic effects are related to the maintenance of BAT functionality, but the signaling remains unexplored. This review provides a summary of RAS counterregulatory actions triggered by Mas and MrgD receptors on adipose tissue plasticity. Focus on the effects related to the morphology and function of adipose tissue, especially from animal studies, will be given targeting new avenues for treatment of obesity‐associated metabolic effects. [ABSTRACT FROM AUTHOR]

The renin‐angiotensin system (RAS) plays a key role in blood pressure regulation. The RAS is a complex interconnected system composed of two axes with opposite effects. The pressor arm, represented by angiotensin (Ang) II and the AT1 receptor (AT1R), mediates the vasoconstrictor, proliferative, hypertensive, oxidative, and pro‐inflammatory effects of the RAS, while the depressor/protective arm, represented by Ang‐(1–7), its Mas receptor (MasR) and the AT2 receptor (AT2R), opposes the actions elicited by the pressor arm. The AT1R, AT2R, and MasR belong to the G‐protein‐coupled receptor (GPCR) family. GPCRs operate not only as monomers, but they can also function in dimeric (homo and hetero) or higher‐order oligomeric states. Due to the interaction with other receptors, GPCR properties may change: receptor affinity, trafficking, signaling, and its biological function may be altered. Thus, heteromerization provides a newly recognized means of modulation of receptor function, as well as crosstalk between GPCRs. This review is focused on angiotensin receptors, and how their properties are influenced by crosstalk with other receptors, adding more complexity to an already complex system and potentially opening up new therapeutic approaches. [ABSTRACT FROM AUTHOR]

Currently, cardiovascular diseases are a major contributor to morbidity and mortality worldwide, having a significant negative impact on both the economy and public health. The renin–angiotensin system contributes to a high spectrum of cardiovascular disorders and is essential for maintaining normal cardiovascular homeostasis. Overactivation of the classical renin–angiotensin system is one of the most important pathophysiological mechanisms in the progression of cardiovascular diseases. The counter-regulatory renin–angiotensin system is an alternate pathway which favors the synthesis of different peptides, including Angiotensin-(1-7), Angiotensin-(1-9), and Alamandine. These peptides, via the angiotensin type 2 receptor (AT2R), MasR, and MrgD, initiate multiple downstream signaling pathways that culminate in the activation of various cardioprotective mechanisms, such as decreased cardiac fibrosis, decreased myocardial hypertrophy, vasodilation, decreased blood pressure, natriuresis, and nitric oxide synthesis. These cardioprotective effects position them as therapeutic alternatives for reducing the progression of cardiovascular diseases. This review aims to show the latest findings on the cardioprotective effects of the main peptides of the counter-regulatory renin–angiotensin system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dietary supplementation with Gryllus assimilis improved malnourished mice. • The cricket promoted body weight gain and reduced adiposity. • Gryllus assimilis positively modulated the expression of antihypertensive genes. Edible insects are recognized as promising food sources due to their nutritional composition. Some species, such as Gryllus assimilis , contain proteins, lipids, and carbohydrates of high biological value, which regulate several metabolic functions, including the Renin-Angiotensin System (RAS). In this context, the present study aimed to assess the effects of dietary supplementation with whole Gryllus assimilis powder on the metabolism of malnourished mice. Thirty-two male Swiss mice were used and divided into four treatment groups. The groups were identified as (AIN93-M); AIN93-M + Gryllus assimilis diet (AIN93-M + GA); AIN93-M + Renutrition diet (AIN93-M + REN) and AIN93-M + Renutrition diet + Gryllus assimilis (AIN93-M + REN + GA). The results showed that whole Gryllus assimilis powder inclusion promotes recovery from protein-energy malnutrition, reduces adiposity, and improves glucose tolerance and insulin sensitivity. It also reduces total cholesterol, triglycerides, VLDL, and adipocyte area. We also observed a significant increase in the expression of RAS-related genes, such as ACE2 and MasR, followed by a reduction in Angiotensinogen and ACE. The main findings of the present study suggest the use of black cricket as a viable strategy for the prevention and treatment of protein-energy malnutrition, as well as the reduction of adiposity, and improvement of lipid and glycemic parameters, with antihypertensive potential. [ABSTRACT FROM AUTHOR]

Cellular ACE2 (cACE2), a vital component of the renin–angiotensin system (RAS), possesses catalytic activity to maintain AngII and Ang 1–7 balance, which is necessary to prevent harmful effects of AngII/AT2R and promote protective pathways of Ang (1−7)/MasR and Ang (1–7)/AT2R. Hemostasis of the brain–RAS is essential for maintaining normal central nervous system (CNS) function. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a viral disease that causes multi-organ dysfunction. SARS-CoV-2 mainly uses cACE2 to enter the cells and cause its downregulation. This, in turn, prevents the conversion of Ang II to Ang (1−7) and disrupts the normal balance of brain–RAS. Brain–RAS disturbances give rise to one of the pathological pathways in which SARS-CoV-2 suppresses neuroprotective pathways and induces inflammatory cytokines and reactive oxygen species. Finally, these impairments lead to neuroinflammation, neuronal injury, and neurological complications. In conclusion, the influence of RAS on various processes within the brain has significant implications for the neurological manifestations associated with COVID-19. These effects include sensory disturbances, such as olfactory and gustatory dysfunctions, as well as cerebrovascular and brain stem-related disorders, all of which are intertwined with disruptions in the RAS homeostasis of the brain. [Display omitted] • This study presents a theoretical perspective on the impact of SARS-CoV-2 on the brain renin–angiotensin system (RAS). • This manuscript highlights the role of cellular ACE2 (cACE2), a key component of the RAS, in maintaining the balance between AngII and Ang 1–7, which is crucial for normal central nervous system (CNS) function. • It explains how SARS-CoV-2 uses cACE2 to enter cells, downregulating cACE2, and disrupting the balance of brain–RAS, leading to various neurological complications. • This manuscript offers a significant contribution to the understanding of how SARS-CoV-2 affects the brain and could be valuable in future research on neurological implications. [ABSTRACT FROM AUTHOR]

[Display omitted] Normal pregnancy (Norm-Preg) is associated with a slight reduction in blood pressure (BP) and decreased BP response to vasoconstrictor stimuli such as angiotensin II (Ang II), although the renin-angiotensin-aldosterone system (RAAS) is upregulated. Preeclampsia (PE) is a complication of pregnancy manifested as hypertension-in-pregnancy (HTN-Preg), and dysregulation of angiotensin biosynthesis and signaling have been implicated. Ang II activates vascular Ang II type-1 receptor (AT 1 R) and Ang II type-2 receptor (AT 2 R), while angiotensin-(1–7) promotes Ang-(1–7)/MasR signaling. The role of AT 1 R in vasoconstriction and the activated cellular mechanisms are well-characterized. The sensitivity of vascular AT 1 R to Ang II and consequent activation of vasoconstrictor mechanisms decrease during Norm-Preg, but dramatically increase in HTN-Preg. Placental ischemia in late pregnancy could also initiate the release of AT 1 R agonistic autoantibodies (AT 1 AA) with significant impact on endothelial dysfunction and activation of contraction pathways in vascular smooth muscle including [Ca2+] c and protein kinase C. On the other hand, the role of AT 2 R and Ang-(1–7)/MasR in vascular relaxation, particularly during Norm-Preg and PE, is less clear. During Norm-Preg, increases in the expression/activity of vascular AT 2 R and Ang-(1–7)/MasR promote the production of endothelium-derived relaxing factors such as nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factor leading to generalized vasodilation. Aortic segments of Preg rats show prominent endothelial AT 2 R staining and increased relaxation and NO production in response to AT 2 R agonist CGP42112A, and treatment with AT 2 R antagonist PD123319 enhances phenylephrine-induced contraction. Decreased vascular AT 2 R and Ang-(1–7)/MasR expression and receptor-mediated mechanisms of vascular relaxation have been suggested in HTN-Preg animal models, but their role in human PE needs further testing. Changes in angiotensin-converting enzyme-2 (ACE2) have been observed in COVID-19 patients, and whether ACE2 influences the course of COVID-19 viral infection/immunity in Norm-Preg and PE is an intriguing area for research. [ABSTRACT FROM AUTHOR]