The acute prothrombotic effect of aldosterone in rats is partially mediated via angiotensin II receptor type 1

COVID-19 associated thyroid dysfunction and other comorbidities and its management using phytochemical-based therapeutics: a natural way

The present severe acute respiratory syndrome-2 (SARS-CoV-2) mediated Coronavirus pandemic (COVID-19) and post-COVID-19 complications affect human life drastically. Patients who have been cured of COVID-19 infection are now experiencing post-COVID-19 associated comorbidities, which have increased mortality rates. The SARS-CoV-2 infection distresses the lungs, kidneys, gastrointestinal tract, and various endocrine glands, including the thyroid. The emergence of variants which includes Omicron (B.1.1.529) and its lineages threaten the world severely. Among different therapeutic approaches, phytochemical-based therapeutics are not only cost-effective but also have lesser side effects. Recently a plethora of studies have shown the therapeutic efficacy of various phytochemicals for the treatment of COVID-19. Besides this, various phytochemicals have been found efficacious in treating several inflammatory diseases, including thyroid-related anomalies. The method of the phytochemical formulation is quick and facile and the raw materials for such herbal preparations are approved worldwide for human use against certain disease conditions. Owing to the advantages of phytochemicals, this review primarily discusses the COVID-19-related thyroid dysfunction and the role of key phytochemicals to deal with thyroid anomaly and post-COVID-19 complications. Further, this review shed light on the mechanism via which COVID-19 and its related complication affect organ function of the body, along with the mechanistic insight into the way by which phytochemicals could help to cure post-COVID-19 complications in thyroid patients. Considering the advantages offered by phytochemicals as a safer and cost-effective medication they can be potentially used to combat COVID-19-associated comorbidities.

Role of the Renin Angiotensin Aldosterone System in the Pathogenesis of Sepsis-Induced Acute Kidney Injury: A Systematic Review

BACKGROUND

Sepsis is a life-threatening condition responsible for up to 20% of all global deaths. Kidneys are among the most common organs implicated, yet the pathogenesis of sepsis-induced acute kidney injury (S-AKI) is not completely understood, resulting in the treatment being nonspecific and responsive. In situations of stress, the renin angiotensin aldosterone system (RAAS) may play a role. This systematic review focuses on analyzing the impact of the RAAS on the development of S-AKI and discussing the use of RAAS antagonists as an emerging therapeutic option to minimize complications of sepsis.

METHODS

Studies were identified using electronic databases (Medline via PubMed, Google Scholar) published within the past decade, comprised from 2014 to 2023. The search strategy was conducted using the following keywords: sepsis, S-AKI, RAAS, Angiotensin II, and RAAS inhibitors. Studies on human and animal subjects were included if relevant to the keywords.

RESULTS

Our search identified 22 eligible references pertaining to the inclusion criteria. Treatment of sepsis with RAAS inhibitor medications is observed to decrease rates of S-AKI, reduce the severity of S-AKI, and offer an improved prognosis for septic patients.

CONCLUSION

The use of RAAS antagonists as a treatment after the onset of sepsis has promising findings, with evidence of decreased renal tissue damage and rates of S-AKI and improved survival outcomes.

REGISTRATION

INPLASY202360098.

The Effect of Aldosterone on Cardiorenal and Metabolic Systems

Aldosterone, a vital hormone of the human body, has various pathophysiological roles. The excess of aldosterone, also known as primary aldosteronism, is the most common secondary cause of hypertension. Primary aldosteronism is associated with an increased risk of cardiovascular disease and kidney dysfunction compared to essential hypertension. Excess aldosterone can lead to harmful metabolic and other pathophysiological alterations, as well as cause inflammatory, oxidative, and fibrotic effects in the heart, kidney, and blood vessels. These alterations can result in coronary artery disease, including ischemia and myocardial infarction, left ventricular hypertrophy, heart failure, arterial fibrillation, intracarotid intima thickening, cerebrovascular disease, and chronic kidney disease. Thus, aldosterone affects several tissues, especially in the cardiovascular system, and the metabolic and pathophysiological alterations are related to severe diseases. Therefore, understanding the effects of aldosterone on the body is important for health maintenance in hypertensive patients. In this review, we focus on currently available evidence regarding the role of aldosterone in alterations of the cardiovascular and renal systems. We also describe the risk of cardiovascular events and renal dysfunction in hyperaldosteronism.

In-stent Thrombosis and COVID-19 Infection: Current Insights on the Mechanistic Relationship

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been demonstrated as a major risk factor in inducing coronary stent thrombosis due to its propensity to create a pro-thrombotic state. This review explores the mechanisms that may contribute to the increased thrombosis risk seen in COVID-19. Furthermore, we discuss the patient and haematological factors that predispose to an increased risk of stent thrombosis, as well as the role of certain antiplatelet and anticoagulation therapies, including ticagrelor and enoxaparin, that may reduce the likelihood and severity of in-stent thrombosis, in SARS-CoV-2 infection. To counter the proinflammatory and pro-thrombotic state shown in COVID-19, anti-thrombotic therapy in the future may be optimised using point-of-care platelet inhibition testing and inflammation-modifying therapies. Large-scale randomised trials with long-term follow-up are increasingly necessary to assess the intersection of COVID-19 and stent optimisation as well as the reduction of stent thrombosis after drug-eluting stent (DES) implantation.

Aldosterone Increases Vascular Permeability in Rat Skin

The aim of this study was to evaluate the effect of acute aldosterone (ALDO) administration on the vascular permeability of skin. ALDO was injected intradermally into rats, and vascular permeability was measured. Eplerenone (EPL), a selective mineralocorticoid receptor (MR) antagonist, was used. Skin biopsies were carried out for immunohistochemical (IHC) staining, and polymerase chain reactions were performed to analyze the expression of MR, 11β-hydroxysteroid dehydrogenase type 2, von Willebrand factor (vWF), vascular endothelial growth factor (VEGF), and zonula occludens 1. Our study showed the presence of MR in the rat skin vasculature for the first time. It was found that ALDO injection resulted in a more than 30% increase in vascular permeability and enhanced the endothelial exocytosis of vWF. The effect of ALDO diminished after EPL administration. An accumulation of vWF and a reduction in VEGF IHC staining were observed following chronic EPL administration. No effect of ALDO or EPL on the mRNA expression of the studied genes or skin structure was observed. The results suggest that ALDO increases vascular permeability in the skin via an MR-dependent mechanism. This effect of ALDO on skin microcirculation may have important therapeutic implications for diseases characterized by increased levels of ALDO and coexisting skin microangiopathy.

Does the Serum Concentration of Angiotensin II Type 1 Receptor Have an Effect on the Severity of COVID-19? A Prospective Preliminary Observational Study among Healthcare Professionals

SARS-CoV-2 is a virus that causes severe respiratory distress syndrome. The pathophysiology of COVID-19 is related to the renin-angiotensin system (RAS). SARS-CoV-2, a vector of COVID-19, uses angiotensin-converting enzyme 2 (ACE-2), which is highly expressed in human lung tissue, nasal cavity, and oral mucosa, to gain access into human cells. After entering the cell, SARS-CoV-2 inhibits ACE-2, thus favouring the ACE/Ang II/angiotensin II type 1 receptor (AT1R) axis, which plays a role in the development of acute lung injury (ALI). This study aimed to analyse the influence of angiotensin 1 receptor (AT1R) levels in the serum on the course of the severity of symptoms in healthcare professionals who had a SARS-CoV-2 infection. This prospective observational study was conducted on a group of 82 participants. The study group included physicians and nurses who had a COVID-19 infection confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) test for SARS-CoV-2. The control group consisted of healthy medical professionals who had not had a SARS-CoV-2 infection or who had no symptoms of COVID-19 and who tested negative for SARS-CoV-2 on the day of examination. We analysed the correlation between AT1R concentration and the severity of COVID-19, as well as with sex, age, blood group, and comorbidities. There were no statistically significant differences in the mean values of AT1R concentration in the recovered individuals and the non-COVID-19 subjects (3.29 vs. 3.76 ng/mL; p = 0.32). The ROC curve for the AT1R assay showed an optimal cut-off point of 1.33 (AUC = 0.44; 95% CI = 0.32-0.57; p = 0.37). There was also no correlation between AT1R concentration and the severity of symptoms associated with COVID-19. Blood type analysis showed statistically significantly lower levels of AT1R in COVID-19-recovered participants with blood group A than in those with blood group O. In conclusion, AT1R concentration does not affect the severity of symptoms associated with COVID-19 among healthcare professionals.

Hyperglycemia Potentiates Prothrombotic Effect of Aldosterone in a Rat Arterial Thrombosis Model

We investigated the role of aldosterone (ALDO) in the development of arterial thrombosis in streptozotocin-induced diabetic rats. To evaluate the effect of endogenous ALDO, the rats underwent adrenalectomy (ADX). ADX reduced the development of arterial thrombosis. A 1 h infusion of ALDO (30 μg/kg/h) enhanced thrombosis in adrenalectomized rats, while this effect was potentiated in diabetic rats. ALDO shortened bleeding time, increased plasma levels of tissue factor (TF) and plasminogen activator inhibitor, decreased plasma level of nitric oxide (NO) metabolites, and increased oxidative stress. Moreover, 2 h incubation of human umbilical vein endothelial cells (HUVECs) with ALDO (10^-7 M) disrupted hemostatic balance in endothelial cells in normoglycemia (glucose 5.5 mM), and this effect was more pronounced in hyperglycemia (glucose 30 mM). We demonstrated that the acute ALDO infusion enhances arterial thrombosis in rats and hyperglycemia potentiates this prothrombotic effect. The mechanism of ALDO action was partially mediated by mineralocorticoid (MR) and glucocorticoid (GR) receptors and related to impact of the hormone on primary hemostasis, TF-dependent coagulation cascade, fibrinolysis, NO bioavailability, and oxidative stress balance. Our in vitro study confirmed that ALDO induces prothrombotic phenotype in the endothelium, particularly under hyperglycemic conditions.

Renin-angiotensin system blockade in the COVID-19 pandemic

In the early months of the coronavirus disease 2019 (COVID-19) pandemic, a hypothesis emerged suggesting that pharmacologic inhibitors of the renin–angiotensin system (RAS) may increase COVID-19 severity. This hypothesis was based on the role of angiotensin-converting enzyme 2 (ACE2), a counterregulatory component of the RAS, as the binding site for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), allowing viral entry into host cells. Extrapolations from prior evidence led to speculation that upregulation of ACE2 by RAS blockade may increase the risk of adverse outcomes from COVID-19. However, counterarguments pointed to evidence of potential protective effects of ACE2 and RAS blockade with regard to acute lung injury, as well as substantial risks from discontinuing these commonly used and important medications. Here we provide an overview of classic RAS physiology and the crucial role of ACE2 in systemic pathways affected by COVID-19. Additionally, we critically review the physiologic and epidemiologic evidence surrounding the interactions between RAS blockade and COVID-19. We review recently published trial evidence and propose important future directions to improve upon our understanding of these relationships.

The paradigm of norgestimate: a third-generation testosterone-derivative progestin with a peripheral anti-androgenic activity and the lowest risk of venous thromboembolism

INTRODUCTION

Norgestimate (NGM) is a testosterone derivative with peculiar receptor activities.

AREAS COVERED

This is a narrative review of the available data on the pharmacotherapy of NGM in combined hormonal contraceptives (CHCs) in terms of contraceptive efficacy, venous thromboembolism (VTE) risk, safety, tolerability and bleeding patterns. A comprehensive literature review was conducted in August 2020 using PubMed with the keyword 'norgestimate'.

EXPERT OPINION

NGM shows a mild estrogenic activity associated with anti-mineralocorticoid and anti-androgenic properties, largely responsible for the cardiovascular safety profile. The anti-androgenic property depends on the androgen receptor (AR) nuclear translocation (AR trafficking and its subnuclear distribution), the inhibition of 5α-reductase activity (it possesses higher activity compared to other available progestins), and the increase on sexual hormone binding globulin (SHBG) levels if combined with an estrogenic counterpart. NGM is one of the molecules that best modulates the power of ethinyl-estradiol on the thromboembolic risk, being associated with the lowest VTE risk between different CHCs. NGM has the advantage of retaining peripheral anti-androgenic activity, demonstrated by the impact on lipid and glucose metabolism, and it should be preferred if compared with other similar progestins of the same class of risk which are much more androgenic, such as levonorgestrel.

Thrombosis in COVID-19

Thrombotic complications are frequent in COVID-19 and contribute significantly to mortality and morbidity. We review several mechanisms of hypercoagulability in sepsis that may be upregulated in COVID-19. These include immune-mediated thrombotic mechanisms, complement activation, macrophage activation syndrome, antiphospholipid antibody syndrome, hyperferritinemia, and renin-angiotensin system dysregulation. We highlight biomarkers within each pathway with potential prognostic value in COVID-19. Lastly, recent observational studies have evaluated a role for the expanded use of therapeutic anticoagulation in COVID-19. We review strengths and weaknesses of these studies, and we also discuss the hypothetical benefit and anticipated challenges of fibrinolytic therapy in COVID-19.

COVID-19 and the renin-angiotensin system (RAS): A spark that sets the forest alight?

The coronavirus disease 2019 (COVID-19) pandemic has increased exponentially in numbers with more than 20 million people infected around the globe. It is clear that COVID-19 is not a simple viral pneumonia, but presents with unusual pathophysiological effects. Of special interest is that SARS-CoV-2 utilises the angiotensin-converting enzyme-2 (ACE2) for cell entry and therefore has a direct effect on the renin angiotensin system (RAS). The RAS is primarily responsible for blood pressure control via the classic pathway. Recently numerous other pathological processes have been described due to stimulation of this classic pathway. There is also a protective RAS pathway medicated by ACE2 which may be suppressed in COVID-19. This leads to overstimulation of the classic pathway with adverse cardiovascular and respiratory effects, hypercoagulation, endothelial dysfunction, inflammation and insulin resistance. We hypothesize that overreaction of the renin-angiotensin-aldosterone may account for the myriad of unusual biochemical and clinical abnormalities noted in patients infected with SARS-CoV-2.

Coronavirus Disease 2019 and Hypertension: The Role of Angiotensin-Converting Enzyme 2 and the Renin-Angiotensin System

Hypertension emerged from early reports as a potential risk factor for worse outcomes for persons with coronavirus disease 2019 (COVID-19). Among the putative links between hypertension and COVID-19 is a key counter-regulatory component of the renin-angiotensin system (RAS): angiotensin-converting enzyme 2 (ACE2). ACE2 facilitates entry of severe acute respiratory syndrome coronavirus 2, the virus responsible for COVID-19, into host cells. Because RAS inhibitors have been suggested to increase ACE2 expression, health-care providers and patients have grappled with the decision of whether to discontinue these medications during the COVID-19 pandemic. However, experimental models of analogous viral pneumonias suggest RAS inhibitors may exert protective effects against acute lung injury. We review how RAS and ACE2 biology may affect outcomes in COVID-19 through pulmonary and other systemic effects. In addition, we briefly detail the data for and against continuation of RAS inhibitors in persons with COVID-19 and summarize the current consensus recommendations from select specialty organizations.

Relationship Between ACE2 and Other Components of the Renin-Angiotensin System

PURPOSE OF THE REVIEW

Angiotensin-converting enzyme 2 (ACE2) is a key counter-regulatory component of the renin-angiotensin system. Here, we briefly review the mechanistic and target organ effects related to ACE2 activity, and the importance of ACE2 in SARS-CoV-2 infection.

RECENT FINDINGS

ACE2 converts angiotensin (Ang) II to Ang-(1-7), which directly opposes the vasoconstrictive, proinflammatory, and prothrombotic effects of Ang II. ACE2 also facilitates SARS-CoV-2 viral entry into host cells. Drugs that interact with the renin-angiotensin system may impact ACE2 expression and COVID-19 pathogenesis; however, the magnitude and direction of these effects are unknown at this time. High quality research is needed to improve our understanding of how agents that act on the renin-angiotensin system impact ACE2 and COVID-19-related disease outcomes.

Rapid effects of aldosterone on platelets, coagulation, and fibrinolysis lead to experimental thrombosis augmentation

An increase in aldosterone levels positively correlates with an increased risk of acute cardiovascular thrombotic events. The aim of the study was to determine the mechanism of action of prothrombotic aldosterone focusing on the rapid effects of the hormone on platelets, coagulation, and fibrinolysis. A wide panel of advanced ex vivo and in vitro techniques was used for the evaluation of coagulation and fibrinolysis in aldosterone-treated rats. Additionally, two experimental mice models of thrombosis, which allowed for the intravital observation of the first stage of thrombus formation in real time, were used. Acute administration of aldosterone in rats increased the density of fibrin net and platelet aggregates in clots as well as reduced fibrinolysis. These effects were observed within 10 min and were partially suppressed by eplerenone. Moreover, acute administration of aldosterone in mice enhanced platelet accumulation at the site of endothelial injury induced by laser and increased the area of irreversibly activated platelets in FeCl₃-induced thrombus. These results demonstrate that aldosterone acutely affects platelets, coagulation, and fibrinolysis, leading to an enhanced thrombosis. The aldosterone effects were mediated partially via a mineralocorticoid receptor. The mechanism seems to involve non-genomic signaling since the effects were observed within a few minutes of aldosterone administration.

Impact of renin-angiotensin system inhibitors continuation versus discontinuation on outcome after major surgery: protocol of a multicenter randomized, controlled trial (STOP-or-NOT trial)

BACKGROUND

Chronic treatment of hypertension or heart failure very often includes an angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) as renin-angiotensin system inhibitors (RASi) treatments. To stop or not to stop these medications before major surgery remains an unresolved issue. The lack of evidence leads to conflicting guidelines with respect to RASi management before major surgery. The purpose of this study is to evaluate the impact of a strategy of RASi continuation or discontinuation on perioperative complications in patients undergoing major non-cardiac surgery.

METHODS

This is a multicenter, open-labeled randomized controlled trial in > 30 French centers. In the experimental group, RASi will be continued while the treatment will be stopped 48 h before the surgery in the control arm. The primary endpoint is a composite endpoint of major complications after surgery. An endpoint adjudication committee will review clinical data and adjudicate efficacy endpoints while blinded to the assigned study drug group. Main analysis will be by intention-to-treat comparing the composite outcome measure at 28 days in the two groups. A total of 2222 patients are planned to detect an absolute complications difference of 5%.

DISCUSSION

The results of the trial should provide robust evidence to anesthesiologists and surgeons regarding management of RASi before major non-cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03374449 . Registered on 11 December 2017.

Cyp2c44 gene disruption exacerbated pulmonary hypertension and heart failure in female but not male mice

Epoxyeicosatrienoicacids (EETs), synthesized from arachidonic acid by epoxygenases of the CYP2C and CYP2J gene subfamilies, contribute to hypoxic pulmonary vasoconstriction (HPV) in mice. Despite their roles in HPV, it is controversial whether EETs mediate or ameliorate pulmonary hypertension (PH). A recent study showed that deficiency of Cyp2j did not protect male and female mice from hypoxia-induced PH. Since CYP2C44 is a functionally important epoxygenase, we hypothesized that knockout of the Cyp2c44 gene would protect both sexes of mice from hypoxia-induced PH. We tested this hypothesis in wild-type (WT) and Cyp2c44 knockout (Cyp2c44 (-/-)) mice exposed to normoxia (room air) and hypoxia (10% O2) for 5 weeks. Exposure of WT and Cyp2c44 (-/-) mice to hypoxia resulted in pulmonary vascular remodeling, increased pulmonary artery resistance, and decreased cardiac function in both sexes. However, in female Cyp2c44 (-/-) mice, compared with WT mice, (1) pulmonary artery resistance and right ventricular hypertrophy were greater, (2) cardiac index was lower, (3) left ventricular and arterial stiffness were higher, and (4) plasma aldosterone levels were higher, but (5) there was no difference in levels of EET in lungs and heart. Paradoxically and unexpectedly, we found that Cyp2c44 disruption exacerbated hypoxia-induced PH in female but not male mice. We attribute exacerbated PH in female Cyp2c44 (-/-) mice to elevated aldosterone and as-yet-unknown systemic factors. Therefore, we suggest a role for the human CYP2C genes in protecting women from severe PH and that this could be one of the underlying causes for a better 5-year survival rate in women than in men.

New agents modulating the renin-angiotensin-aldosterone system-Will there be a new therapeutic option?

The renin-angiotensin-aldosterone system (RAAS) is more complex than it was originally regarded. According to the current subject knowledge, there are two main axes of the RAAS: (1) angiotensin-converting enzyme (ACE)-angiotensin II-AT₁ receptor axis and (2) ACE2-angiotensin-(1-7)-Mas receptor axis. The activation of the first axis leads to deleterious effects, including vasoconstriction, endothelial dysfunction, thrombosis, inflammation, and fibrosis; therefore, blocking the components of this axis is a highly rational and commonly used therapeutic procedure. The ACE2-Ang-(1-7)-Mas receptor axis has a different role, since it often opposes the effects induced by the classical ACE-Ang II-AT₁ axis. Once the positive effects of the ACE2-Ang-(1-7)-Mas axis were discovered, the alternative ways of pharmacotherapy activating this axis of RAAS appeared. This article briefly describes new molecules affecting the RAAS, namely: recombinant human ACE2, ACE2 activators, angiotensin-(1-7) peptide and non-peptide analogs, aldosterone synthase inhibitors, and the third and fourth generation of mineralocorticoid receptor antagonists. The results of the experimental and clinical studies are encouraging, which leads us to believe that these new molecules can support the treatment of cardiovascular diseases as well as cardiometabolic disorders.