The past, present and future of renin-angiotensin aldosterone system inhibition

A comprehensive review of finerenone-a third-generation non-steroidal mineralocorticoid receptor antagonist

Multiple studies have shown that finerenone (BAY 94-8862), a third-generation non-steroidal mineralocorticoid receptor antagonist (MRA), possesses different or superior mechanisms of action to traditional MRAs. Specifically, animal and cell-based experiments have demonstrated that this compound exerts multiple effects including fibrosis inhibition, reduced pulmonary artery pressure, improved diabetic retinopathy, enhanced endothelial functions, metabolic optimization as well as reduced oxidative stress, thereby exerting overall positive effects on renal and cardiovascular diseases. Consequently, clinical research, such as the FIGARO-DKD and FIDELIO-DKD trials, has demonstrated dual benefits for patients with type 2 diabetes mellitus and chronic kidney disease (T2DM-CKD), especially by validating MRAs' potential in reducing risks of renal and cardiovascular composite endpoints. Currently, cardiovascular indications for finerenone are limited to patients with T2DM-CKD, while its use in non-T2DM CKD patients remains at clinical trial stages. Despite showing good safety and efficacy in T2DM-CKD patients, there are insufficient corresponding data for those presenting chronic kidney disease without diabetes (ndCKD). Furthermore, the application of this compound in diseases such as primary aldosteronism and its association with cancer risk need to be further validated through larger-scale and longer-term clinical studies. Nevertheless, the development of finerenone provides an additional option for treating cardiovascular and renal diseases. With further research, it is expected that finerenone will be relevant to a broader range of CKD patient populations by addressing current knowledge gaps to comprehensively evaluate its clinical value and potentially alter existing treatment strategies. The current review aims to comprehensively analyze the basic research and clinical advancements involving finerenone in order to explore its prospects for treating cardiovascular and renal diseases, while addressing unmet needs in current treatment strategies. Additionally, through a comprehensive analysis of relevant research findings, a deeper understanding of finerenone's drug characteristics will be provided alongside scientific guidance for future treatment strategies and their clinical significance.

Alleviating Hypertension by Selectively Targeting Angiotensin Receptor-Expressing Vagal Sensory Neurons

Cardiovascular homeostasis is maintained, in part, by neural signals arising from arterial baroreceptors that apprise the brain of blood volume and pressure. Here, we test whether neurons within the nodose ganglia that express angiotensin type-1a receptors (referred to as NGAT1aR) serve as baroreceptors that differentially influence blood pressure (BP) in male and female mice. Using Agtr1a-Cre mice and Cre-dependent AAVs to direct tdTomato to NGAT1aR, neuroanatomical studies revealed that NGAT1aR receive input from the aortic arch, project to the caudal nucleus of the solitary tract (NTS), and synthesize mechanosensitive ion channels, Piezo1/2 To evaluate the functionality of NGAT1aR, we directed the fluorescent calcium indicator (GCaMP6s) or the light-sensitive channelrhodopsin-2 (ChR2) to Agtr1a-containing neurons. Two-photon intravital imaging in Agtr1a-GCaMP6s mice revealed that NGAT1aR couple their firing to elevated BP, induced by phenylephrine (i.v.). Furthermore, optical excitation of NGAT1aR at their soma or axon terminals within the caudal NTS of Agtr1a-ChR2 mice elicited robust frequency-dependent decreases in BP and heart rate, indicating that NGAT1aR are sufficient to elicit appropriate compensatory responses to vascular mechanosensation. Optical excitation also elicited hypotensive and bradycardic responses in ChR2-expressing mice that were subjected to deoxycorticosterone acetate (DOCA)-salt hypertension; however, the duration of these effects was altered, suggestive of hypertension-induced impairment of the baroreflex. Similarly, increased GCaMP6s fluorescence observed after administration of phenylephrine was delayed in mice subjected to DOCA-salt or chronic delivery of angiotensin II. Collectively, these results reveal the structure and function of NGAT1aR and suggest that such neurons may be exploited to discern and relieve hypertension.

Systematic Review of Cardiovascular Benefits and Safety of Sacubitril-Valsartan in End-Stage Kidney Disease

Introduction

Patients with end-stage kidney disease (ESKD) frequently develop heart failure, contributing to high mortality. Limited data exist on cardiovascular benefits and safety of sacubitril-valsartan in this population. Our systematic review aims to evaluate the efficacy and safety of sacubitril-valsartan versus standard care in patients with ESKD who are on dialysis.

Methods

We conducted a search in Embase, MEDLINE, and Cochrane databases to identify relevant studies and assessed outcomes using random-effect model and generic inverse variance approach.

Results

Analysis of 12 studies involving 799 eligible patients with ESKD revealed improvement in left ventricular ejection fraction (LVEF) with sacubitril-valsartan compared to a control group with pooled mean difference (MD) 6.58% (95% confidence interval [CI]: 1.86, 11.29). LVEF significantly improved in patients with LVEF <50% (heart failure with reduced ejection fraction [HFrEF] and heart failure with moderately reduced ejection fraction [HFmrEF]) with MD 12.42% (95% CI: 9.39, 15.45). However, patients with LVEF >50% (heart failure with preserved ejection fraction [HFpEF]) did not exhibit statistically significant effect, MD 2.6% (95% CI: 1.15, 6.35). Sacubitril-valsartan significantly enhanced LVEF in patients with HFrEF, with MD 13.8% (95% CI: 12.04, 15.82). Safety analysis indicated no differences in incidence of hyperkalemia (pooled odds ratio [OR] 0.72; 95% CI: 0.38, 1.36) or hypotension (pooled risk ratio [RR] 1.03; 95% CI: 0.36, 2.98). No cases of angioedema were reported. However, safety analysis relies on evidence of limited robustness due to the observational nature of the studies.

Conclusion

Our systematic review suggests that sacubitril-valsartan benefits patients with ESKD with HFrEF and HFmrEF by improving LVEF without increasing the risk of hyperkalemia, hypotension, or angioedema compared to standard care. However, safety analysis based on observational studies inherently has limitations for establishing causal relationships.

Protective effect of novel angiotensin receptor neprilysin inhibitor S086 on target organ injury in spontaneously hypertensive rats

BACKGROUND

Hypertension is a clinical syndrome characterized by elevated systemic arterial blood pressure associated with injury to the heart, kidney, brain, and other organs. Angiotensin receptor neprilysin inhibitors (ARNi), including angiotensin receptor blockers (ARBs) and neprilysin inhibitors (NEPi), have been shown to be safe and effective at reducing blood pressure and alleviating development of target organ injury. This study was used to develop S086 as a novel ARNi and conducted preclinical studies in animal models to evaluate the protective effects of S086 on target organs.

METHODS

This study used a 14-month-old spontaneously hypertensive rat (SHR) model to evaluate the protective effects of S086 on the cardiovascular system and organs such as heart and kidney by blood pressure monitoring, urine and blood examination, pathological examination, and immunological index detection.

RESULTS

After administering S086 orally to the SHR, their blood pressure and levels of renal injury indicators such as serum creatinine and urinary microalbumin were reduced, and myocardial cell necrosis and cardiac fibrosis of the heart were significantly improved. In addition, there were also significantly improvements in the histological lesions of blood vessels and the kidneys.

CONCLUSIONS

The findings showed that S086 effectively reduced the blood pressure of SHR and had effects on alleviating development of heart, blood vessels and kidney.

Therapeutic potential of Ganoderma lucidum polysaccharide peptide in Doxorubicin-induced nephropathy: modulation of renin-angiotensin system and proteinuria

Introduction: In the Doxorubicin (DOX)-induced nephropathy model, proteinuria is a manifestation of progressive kidney injury. The pathophysiology of renal illness is heavily influenced by the renin-angiotensin system (RAS). To reduce renal RAS activation and proteinuria caused by DOX, this study evaluated the effectiveness of Ganoderma lucidum polysaccharide peptide (GL-PP), a new glycopeptide produced from Ganoderma lucidum grown on grass. Methods: Three groups of BALB/c male mice were created: control, DOX, and DOX + GL-PP. GL-PP (100 mg/kg) was administered to mice by intraperitoneal injection for 4 weeks following a single intravenous injection of DOX (10 mg/kg via the tail vein). Results: After 4 weeks, full-length and soluble pro(renin) receptor (fPRR/sPRR) overexpression in DOX mouse kidneys, which is crucial for the RAS pathway, was dramatically inhibited by GL-PP therapy. Additionally, GL-PP successfully reduced elevation of urinary renin activity and angiotensin II levels, supporting the idea that GL-PP inhibits RAS activation. Moreover, GL-PP showed a considerable downregulation of nicotinamide adenine nucleotide phosphate oxidase 4 (NOX4) expression and a decrease in hydrogen peroxide (H2O2) levels. GL-PP treatment effectively reduced glomerular and tubular injury induced by DOX, as evidenced by decreased proteinuria, podocyte damage, inflammation, oxidative stress, apoptosis, and fibrosis. Discussion: GL-PP inhibits intrarenal PRR/sPRR-RAS activation and upregulation of NOX4 and H2O2, suggesting potential therapeutic approaches against DOX-induced nephropathy.

Telmisartan versus EnalapRil In heart failure with redUced ejection fraction patients with Moderately impaired kidney Functions; randomized controlled trial: "TRIUMF trial"

BACKGROUND

When heart failure with reduced ejection fraction (HFrEF) and chronic kidney disease (CKD) co-exist, Renin angiotensin-aldosterone system inhibitors (RAASi) are often underutilized for the fear of worsening renal function (WRF). Telmisartan is a RAASi characteristic for a favorable renal profile, although data on its utility in HFrEF is limited. This study aimed to compare efficacy and tolerability of Telmisartan versus Enalapril in patients with HFrEF and CKD.

RESULTS

This study randomized 107 patients with HFrEF and CKD to either Telmisartan (10-80 mg) or Enalapril (5-40 mg) daily. The achieved RAASi dose, dose reductions (DR) or dis-continuation (DC), death/Heart failure rehospitalization (HFH), NYHA class and 6MWT were compared at 3- and 6-months. At 3- and 6-months, 93.5% versus 68.6% and 95.2% versus 72.9% were maintaining ≥ 50% of the target dose in the Telmisartan- versus Enalapril-group, respectively. Despite the higher achieved dose by 3- and 6-months, Telmisartan versus Enalapril was associated with less WRF (6.4% vs. 22.9%, p = 0.022 and 7.3% vs. 13.6%, p = 0.28) and fewer episodes of DR-DC (31.9% vs. 55.1%, p = 0.018 and 35.7% vs. 56.5%, p = 0.041), respectively. By the end of the study, there were 5 deaths in each group, yet, HFH occurred in 34.1% versus 55.3%, p = 0.035, and NYHA class changed by - 1 [- 2, 0] versus 0 [- 1, 1], p = 0.017 in Telmisartan- versus Enalapril patients, respectively. Within-group results showed improvement in 6MWT in Telmisartan-, and increase in diuretic requirements in Enalapril-group.

CONCLUSIONS

In patients with HFrEF and CKD, Telmisartan was better tolerated to uptitrate, caused less WRF, less HFH and showed better functional improvement compared to Enalapril. Clinical trial registration This study was prospectively registered on clinicaltrials.gov, with registration number (NCT04736329).

Renin-Angiotensin-Aldosterone System Inhibitors Are Associated With Favorable Outcomes Compared to Beta Blockers in Reducing Mortality Following Abdominal Aneurysm Repair

Background The best medical therapy to control hypertension following abdominal aortic aneurysm repair is yet to be determined. We therefore examined whether treatment with renin-angiotensin-aldosterone system inhibitors (RAASIs) versus beta blockers influenced postoperative and 1-year clinical end points following abdominal aortic aneurysm repair in a Medicare-linked database. Methods and Results All patients with hypertension undergoing endovascular aneurysm repair and open aneurysm repair in the Vascular Quality Initiative Vascular Implant Surveillance and Interventional Outcomes Network database between 2003 and 2018 were included. Patients were divided into 2 groups based on their preoperative and discharge medications, either RAASIs or beta blockers. Our cohort included 8789 patients, of whom 3523 (40.1%) were on RAASIs, and 5266 (59.9%) were on beta blockers. After propensity score matching, there were 3053 matched pairs of patients in each group. After matching, RAASI use was associated with lower risk of postoperative mortality (odds ratio [OR], 0.3 [95% CI, 0.1-0.6]), myocardial infarction (OR, 0.1 [95% CI, 0.03-0.6]), and nonhome discharge (OR, 0.6 [95% CI, 0.5-0.7]). Before propensity score matching, RAASI use was associated with lower 1-year mortality (hazard ratio [HR], 0.4 [95% CI, 0.4-0.5]) and lower risk of aneurysmal rupture (HR, 0.7 [95% CI, 0.5-0.9]). These results persisted after propensity score matching for mortality (HR, 0.4 [95% CI, 0.4-0.5]) and aneurysmal rupture (HR, 0.7 [95% CI, 0.5-0.9]). Conclusions In this large contemporary retrospective cohort study, RAASI use was associated with favorable postoperative outcomes compared with beta blockers. It was also associated with lower mortality and aneurysmal rupture at 1 year of follow-up.

Exploration of multifaceted molecular mechanism of angiotensin-converting enzyme 2 (ACE2) in pathogenesis of various diseases

Angiotensin converting enzyme 2 (ACE2) is a homolog of ACE (a transmembrane bound dipeptidyl peptidase enzyme). ACE2 converts angiotensinogen to the heptapeptide angiotensin-(1-7). ACE2 and its product, angiotensin-(1-7), have counteracting effects against the adverse actions of other members of renin-angiotensin system (RAS). ACE2 and its principal product, angiotensin-(1-7), were considered an under recognized arm of the RAS. The COVID-19 pandemic brought to light this arm of RAS with special focus on ACE2. Membrane bound ACE2 serves as a receptor for SARS-CoV-2 viral entry through spike proteins. Apart from that, ACE2 is also involved in the pathogenesis of various other diseases like cardiovascular disease, cancer, respiratory diseases, neurodegenerative diseases and infertility. The present review focuses on the molecular mechanism of ACE2 in neurodegenerative diseases, cancer, cardiovascular disease, infertility and respiratory diseases, including SARS-CoV-2. This review summarizes unveiled roles of ACE2 in the pathogenesis of various diseases which further provides intriguing possibilities for the use of ACE2 activators and RAS modulating agents for various diseases.

Unraveling the Underlying Molecular Mechanism of 'Silent Hypoxia' in COVID-19 Patients Suggests a Central Role for Angiotensin II Modulation of the AT1R-Hypoxia-Inducible Factor Signaling Pathway

A few days after being infected with SARS-CoV-2, a fraction of people remain asymptomatic but suffer from a decrease in arterial oxygen saturation in the absence of apparent dyspnea. In light of our clinical investigation on the modulation of molecules belonging to the renin angiotensin system (RAS) in COVID-19 patients, we propose a model that explains 'silent hypoxia'. The RAS imbalance caused by SARS-CoV-2 results in an accumulation of angiotensin 2 (Ang II), which activates the angiotensin 2 type 1 receptor (AT1R) and triggers a harmful cascade of intracellular signals leading to the nuclear translocation of the hypoxia-inducible factor (HIF)-1α. HIF-1α transactivates many genes including the angiotensin-converting enzyme 1 (ACE1), while at the same time, ACE2 is downregulated. A growing number of cells is maintained in a hypoxic condition that is self-sustained by the presence of the virus and the ACE1/ACE2 ratio imbalance. This is associated with a progressive worsening of the patient's biological parameters including decreased oxygen saturation, without further clinical manifestations. When too many cells activate the Ang II-AT1R-HIF-1α axis, there is a 'hypoxic spillover', which marks the tipping point between 'silent' and symptomatic hypoxia in the patient. Immediate ventilation is required to prevent the 'hypoxic spillover'.

An update on angiotensin-converting enzyme 2 structure/functions, polymorphism, and duplicitous nature in the pathophysiology of coronavirus disease 2019: Implications for vascular and coagulation disease associated with severe acute respiratory syndrome coronavirus infection

It has been known for many years that the angiotensin-converting enzyme 2 (ACE2) is a cell surface enzyme involved in the regulation of blood pressure. More recently, it was proven that the severe acute respiratory syndrome coronavirus (SARS-CoV-2) interacts with ACE2 to enter susceptible human cells. This functional duality of ACE2 tends to explain why this molecule plays such an important role in the clinical manifestations of coronavirus disease 2019 (COVID-19). At the very start of the pandemic, a publication from our Institute (entitled "ACE2 receptor polymorphism: susceptibility to SARS-CoV-2, hypertension, multi-organ failure, and COVID-19 disease outcome"), was one of the first reviews linking COVID-19 to the duplicitous nature of ACE2. However, even given that COVID-19 pathophysiology may be driven by an imbalance in the renin-angiotensin system (RAS), we were still far from understanding the complexity of the mechanisms which are controlled by ACE2 in different cell types. To gain insight into the physiopathology of SARS-CoV-2 infection, it is essential to consider the polymorphism and expression levels of the ACE2 gene (including its alternative isoforms). Over the past 2 years, an impressive amount of new results have come to shed light on the role of ACE2 in the pathophysiology of COVID-19, requiring us to update our analysis. Genetic linkage studies have been reported that highlight a relationship between ACE2 genetic variants and the risk of developing hypertension. Currently, many research efforts are being undertaken to understand the links between ACE2 polymorphism and the severity of COVID-19. In this review, we update the state of knowledge on the polymorphism of ACE2 and its consequences on the susceptibility of individuals to SARS-CoV-2. We also discuss the link between the increase of angiotensin II levels among SARS-CoV-2-infected patients and the development of a cytokine storm associated microvascular injury and obstructive thrombo-inflammatory syndrome, which represent the primary causes of severe forms of COVID-19 and lethality. Finally, we summarize the therapeutic strategies aimed at preventing the severe forms of COVID-19 that target ACE2. Changing paradigms may help improve patients' therapy.

The effect of a low dose hydrogen-oxygen mixture inhalation in midlife/older adults with hypertension: A randomized, placebo-controlled trial

Objective: To explore the effect of a low-dose hydrogen-oxygen (H2-O2) mixture inhalation in midlife/older adults with hypertension. Methods: This randomized, placebo-controlled trial included 60 participants with hypertension aged 50-70 years who were randomly divided into Air group (inhaled placebo air) or H2-O2 group [inhaled H2-O2 mixture (66% H2/33% O2)]. Participants in both groups were treated 4 h per day for 2 weeks. Four-limb blood pressure and 24-h ambulatory blood pressure were monitored before and after the intervention, and levels of plasma hormones related to hypertension were determined. Results: A total of 56 patients completed the study (27 in the Air group and 29 in the H2-O2 group). The right and left arm systolic blood pressure (SBP) were significantly decreased in H2-O2 group compared with the baseline levels (151.9 ± 12.7 mmHg to 147.1 ± 12.0 mmHg, and 150.7 ± 13.3 mmHg to 145.7 ± 13.0 mmHg, respectively; all p < 0.05). Meanwhile, the H2-O2 intervention significantly decreased diastolic nighttime ambulatory blood pressure by 2.7 ± 6.5 mmHg (p < 0.05). All blood pressures were unaffected in placebo group (all p > 0.05). When stratified by age (aged 50-59 years versus aged 60-70 years), participants in the older H2-O2 group showed a larger reduction in right arm SBP compared with that in the younger group (p < 0.05). In addition, the angiotensin II, aldosterone, and cortisol levels as well as the aldosterone-to-renin ratio in plasma were significantly lower in H2-O2 group compared with baseline (p < 0.05). No significant differences were observed in the Air group before and after the intervention. Conclusion: Inhalation of a low-dose H2-O2 mixture exerts a favorable effect on blood pressure, and reduces the plasma levels of hormones associated with hypertension on renin-angiotensin-aldosterone system and stress in midlife/older adults with hypertension.

Endogenous Vasoactive Peptides and Vascular Aging-Related Diseases

Vascular aging is a specific type of organic aging that plays a central role in the morbidity and mortality of cardiovascular and cerebrovascular diseases among the elderly. It is essential to develop novel interventions to prevent/delay age-related vascular pathologies by targeting fundamental cellular and molecular aging processes. Endogenous vasoactive peptides are compounds formed by a group of amino acids connected by peptide chains that exert regulatory roles in intercellular interactions involved in a variety of biological and pathological processes. Emerging evidence suggests that a variety of vasoactive peptides play important roles in the occurrence and development of vascular aging and related diseases such as atherosclerosis, hypertension, vascular calcification, abdominal aortic aneurysms, and stroke. This review will summarize the cumulative roles and mechanisms of several important endogenous vasoactive peptides in vascular aging and vascular aging-related diseases. In addition, we also aim to explore the promising diagnostic function as biomarkers and the potential therapeutic application of endogenous vasoactive peptides in vascular aging-related diseases.

Antihypertensive drugs and brain function: mechanisms underlying therapeutically beneficial and harmful neuropsychiatric effects

A bidirectional relationship exists between hypertension and psychiatric disorders, including unipolar and bipolar depression, anxiety, post-traumatic stress disorder (PTSD), psychosis, schizophrenia, mania, and dementia/cognitive decline. Repurposing of antihypertensive drugs to treat mental disorders is thus being explored. A systematic knowledge of the mechanisms of action and clinical consequences of the use of antihypertensive agents on neuropsychiatric functions has not been achieved yet. In this article, we review the putative role of antihypertensive agents in psychiatric disorders, discuss the targets and mechanisms of action, and examine how and to what extent specific drug classes/molecules may trigger, worsen, or mitigate psychiatric symptoms. In addition, we review pharmacokinetics (brain penetration of drugs) and pharmacogenetics data that add important information to assess risks and benefits of antihypertensive drugs in neuropsychiatric settings. The scientific literature shows robust evidence of a positive effect of α1 blockers on PTSD symptoms, nightmares and sleep quality, α2 agonists on core symptoms, executive function and quality of life in Attention-Deficit/Hyperactivity Disorder, PTSD, Tourette's syndrome, and β blockers on anxiety, aggression, working memory, and social communication. Renin-angiotensin system modulators exert protective effects on cognition, depression, and anxiety, and the loop diuretic bumetanide reduced the core symptoms of autism in a subset of patients. There is no evidence of clear benefits of calcium channel blockers in mood disorders in the scientific literature. These findings are mainly from preclinical studies; clinical data are still insufficient or of anecdotal nature, and seldom systematic. The information herewith provided can support a better therapeutic approach to hypertension, tailored to patients with, or with high susceptibility to, psychiatric illness. It may prompt clinical studies exploring the potential benefit of antihypertensive drugs in selected patients with neuropsychiatric comorbidities that include outcomes of neuropsychiatric interest and specifically assess undesirable effects or interactions.

Angiotensin II Promotes SARS-CoV-2 Infection via Upregulation of ACE2 in Human Bronchial Cells

Blockers of the renin-angiotensin system (RAS) have been reported to increase the angiotensin converting enzyme (ACE)2, the cellular receptor of SARS-CoV-2, and thus the risk and course of COVID-19. Therefore, we investigated if angiotensin (Ang) II and RAS blockers affected ACE2 expression and SARS-CoV-2 infectivity in human epithelial bronchial Calu-3 cells. By infectivity and spike-mediated cell–cell fusion assays, we showed that Ang II acting on the angiotensin type 1 receptor markedly increased ACE2 at mRNA and protein levels, resulting in enhanced SARS-CoV-2 cell entry. These effects were abolished by irbesartan and not affected by the blockade of ACE-1-mediated Ang II formation with ramipril, and of ACE2- mediated Ang II conversion into Ang 1-7 with MLN-4760. Thus, enhanced Ang II production in patients with an activated RAS might expose to a greater spread of COVID-19 infection in lung cells. The protective action of Angiotensin type 1 receptor antagonists (ARBs) documented in these studies provides a mechanistic explanation for the lack of worse outcomes in high-risk COVID-19 patients on RAS blockers.

Classical and Counter-Regulatory Renin-Angiotensin System: Potential Key Roles in COVID-19 Pathophysiology

In the current COVID-19 pandemic, severe acute respiratory syndrome coronavirus 2 uses angiotensin-converting enzyme-2 (ACE-2) receptors for cell entry, leading to ACE-2 dysfunction and downregulation, which disturb the balance between the classical and counter-regulatory renin-angiotensin system (RAS) in favor of the classical RAS. RAS dysregulation is one of the major characteristics of several cardiovascular diseases; thus, adjustment of this system is the main therapeutic target. RAS inhibitors-particularly angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs)-are commonly used for treatment of hypertension and cardiovascular disease. Patients with cardiovascular diseases are the group most commonly seen among those with COVID-19 comorbidity. At the beginning of this pandemic, a dilemma occurred regarding the use of ACEIs and ARBs, potentially aggravating cardiovascular and pulmonary dysfunction in COVID-19 patients. Urgent clinical trials from different countries and hospitals reported that there is no association between RAS inhibitor treatment and COVID-19 infection or comorbidity complication. Nevertheless, the disturbance of the RAS that is associated with COVID-19 infection and the potential treatment targeting this area have yet to be resolved. In this review, the link between the dysregulation of classical RAS and counter-regulatory RAS activities in COVID-19 patients with cardiovascular metabolic diseases is investigated. In addition, the latest findings based on ACEI and ARB administration and ACE-2 availability in relation to COVID-19, which may provide a better understanding of the RAS contribution to COVID-19 pathology, are discussed, as they are of the utmost importance amid the current pandemic.

COVID-19 and male reproductive system: pathogenic features and possible mechanisms

Multiorgan dysfunction is the main characteristic of severe COVID-19 patients and the involvement of male reproductive system may occur among these patients. Although there is a limited evidence to confirm the orchitis and virus presence in the semen of patients, there are concerns about the transmission of virus through the semen. In addition, reduced fertility or infertility can be seen as consequences of severe COVID-19 in recovered subjects. In this study, we aimed to review articles related to COVID-19 and male reproductive system to find the possible underlying mechanisms of SARS-CoV-2 in affecting male fertility. The following keywords of SARS-CoV-2, COVID-19, testis, orchitis, semen, angiotensin-converting enzyme 2 (ACE2), hypothalamic-pituitary-testicular (HPT) axis, Hypothalamus, etc., were defined to find the related publications from standard search engines, e.g., PUBMED, SCOPUS, Google Scholar. According to studies, COVID-19 occurs in severe patients as respiratory disease, along with multi-organ failure. The most important mechanisms are classified as direct and indirect pathogenesis of SARS-CoV-2. The presence of ACE2 on the cell surface of various cells in testis increases the risk of direct infection by this virus. SARS-CoV-2 also affects the testis through the cytokine storm. In addition, the important role of HPT axis dysregulation through impaired Leydig cells and hypothalamus should be considered. Using antiviral and immunomodulatory therapy can be harmful for testis function. Further investigations are required to investigate potential mechanisms of male infertility in survivals of COVID-19. Since involvement of testis is essential for fertility, increasing the knowledge of health system may improve the outcomes.

Combination of Angiotensin (1-7) Agonists and Convalescent Plasma as a New Strategy to Overcome Angiotensin Converting Enzyme 2 (ACE2) Inhibition for the Treatment of COVID-19

Coronavirus disease-2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently the most concerning health problem worldwide. SARS-CoV-2 infects cells by binding to angiotensin-converting enzyme 2 (ACE2). It is believed that the differential response to SARS-CoV-2 is correlated with the differential expression of ACE2. Several reports proposed the use of ACE2 pharmacological inhibitors and ACE2 antibodies to block viral entry. However, ACE2 inhibition is associated with lung and cardiovascular pathology and would probably increase the pathogenesis of COVID-19. Therefore, utilizing ACE2 soluble analogs to block viral entry while rescuing ACE2 activity has been proposed. Despite their protective effects, such analogs can form a circulating reservoir of the virus, thus accelerating its spread in the body. Levels of ACE2 are reduced following viral infection, possibly due to increased viral entry and lysis of ACE2 positive cells. Downregulation of ACE2/Ang (1-7) axis is associated with Ang II upregulation. Of note, while Ang (1-7) exerts protective effects on the lung and cardiovasculature, Ang II elicits pro-inflammatory and pro-fibrotic detrimental effects by binding to the angiotensin type 1 receptor (AT1R). Indeed, AT1R blockers (ARBs) can alleviate the harmful effects associated with Ang II upregulation while increasing ACE2 expression and thus the risk of viral infection. Therefore, Ang (1-7) agonists seem to be a better treatment option. Another approach is the transfusion of convalescent plasma from recovered patients with deteriorated symptoms. Indeed, this appears to be promising due to the neutralizing capacity of anti-COVID-19 antibodies. In light of these considerations, we encourage the adoption of Ang (1-7) agonists and convalescent plasma conjugated therapy for the treatment of COVID-19 patients. This therapeutic regimen is expected to be a safer choice since it possesses the proven ability to neutralize the virus while ensuring lung and cardiovascular protection through modulation of the inflammatory response.

Effects of enzymatically hydrolysed poultry byproduct meal in extruded diets on serum angiotensin-converting enzyme activity and aldosterone in cats

Several peptides found in hydrolysed poultry byproduct meal can inhibit angiotensin-converting enzyme (ACE) activity, a property that indicates potential antihypertensive and health-promoting effects. This study aimed to assess the effects of extruded diets containing enzymatically hydrolysed poultry byproduct meal (HPM) on cat serum ACE activity and aldosterone (ALD) concentration, nutrient digestibility, and faecal characteristics. On the basis of a preliminary in vitro ACE inhibitory activity assay, a commercial HPM and a commercial conventional poultry byproduct meal (CPM) were selected for further investigation. Two isoenergetic and isonitrogenous diets were formulated: CPM diet (25.7% CPM) and HPM diet (24.7% HPM). In trial 1, the effect of diet on serum ACE activity and ALD concentration was evaluated using 8 healthy cats (4 female and 4 male, 4.1 ± 0.38 kg BW) in a crossover design, with 5 d of adaptation and blood collection on d 6. In trial 2, apparent total tract digestibility and faecal characteristics were evaluated using 12 cats (6 female and 6 male, 4.0 ± 0.72 kg BW) in a completely randomised design. Serum ACE and ALD were analysed using a mixed model, with diet as the fixed effect and cat as the random effect. Data from trial 2 were subjected to analysis of variance, and means were compared by Tukey's test. In vitro ACE inhibitory activity of HPM (90.4%) was higher than that of CPM (52.0%). Cats fed the HPM diet tended to have lower serum ACE activity than those fed the CPM diet (126 versus 142 U/l, p = 0.09). Serum ALD was not influenced by diet. Diets had similar digestibility values, and faecal consistency scores tended to be higher (firmer faeces) in cats fed the CPM diet than in cats fed the HPM diet (4.6 versus 4.0, p = 0.09). Inclusion of HPM in extruded diets may reduce cat serum ACE activity and promote good faecal consistency without affecting digestibility. Further investigations are needed to explore the potential health benefits of HPM in hypertensive cats.

Efficacy and safety of early initiation of eplerenone treatment in patients with acute heart failure (EARLIER trial): a multicenter, randomized, double-blind, placebo-controlled trial

AIMS

A mineralocorticoid receptor antagonist (MRA) is effective in patients with chronic heart failure; however, the effects of the early initiation of an MRA in patients with acute heart failure (AHF) have not been elucidated.

METHODS AND RESULTS

In this multicenter, randomized, double-blind, placebo-controlled, parallel-group study, we focused on the safety and effectiveness of the treatment with eplerenone, a selective MRA in 300 patients with AHF, that is, 149 in the eplerenone group and 151 in the placebo group in 27 Japanese institutions. The key inclusion criteria were (1) patients aged 20 years or older and (2) those with left ventricular ejection fraction of ≤ 40%. The primary outcome was a composite of cardiac death or first re-hospitalization due to cardiovascular disease within 6 months. The mean age of the participants was 66.8 years, 27.3% were women, and the median levels of brain natriuretic peptide were 376.0 pg/mL. The incidences of the primary outcome were 19.5% in the eplerenone group and 17.2% in the placebo group (hazard ratio (HR): 1.09, 95% confidence interval (CI): 0.642-1.855). In prespecified secondary outcomes, HR for the composite endpoint, cardiovascular death, or first re-hospitalization due to heart failure (HF) within 6 months was 0.55 (95% CI: 0.213 to 1.434). The safety profile for eplerenone was as expected.

CONCLUSION

The early initiation of eplerenone in patients with AHF could safely be utilized. The reduction of the incidence of a composite of cardiovascular death or first re-hospitalization for cardiovascular diseases by eplerenone is inconclusive because of inadequate power.

The Role of Natural Killer (NK) Cells in Acute Coronary Syndrome: A Comprehensive Review

With poor outcomes and an immense financial burden, acute coronary syndrome (ACS) and its ischemic repercussions still present a major global health problem. Unfavorable outcomes seem to be mainly due to adverse cardiac remodeling. Since the inflammatory response takes an important role in remodeling secondary to myocardial infarction (MI), and as inflammation in this manner has not been completely elucidated, we attempted to give rise to a further understanding of ACS pathophysiology. Hence, in this review, we integrated current knowledge of complex communication networks between natural killer (NK) cells and immune and resident heart cells in the context of ACS. Based on available data, the role of NK cells seems to be important in the infarcted myocardium, where it affects heart remodeling. On the other hand, in atherosclerotic plaque, NK cells seem to be mere passers-by, except in the case of chronic infections by atherogenic pathogens. In that case, NK cells seem to support proinflammatory milieu. NK cell research is challenging due to ethical reasons, convergent evolution, and phenotypic diversity among individuals. Therefore, we argue that further research of NK cells in ACS is valuable, given their therapeutic potential in improving postischemic heart remodeling.

Inhibition of Angiotensin Converting Enzyme Impairs Anti-staphylococcal Immune Function in a Preclinical Model of Implant Infection

Background: Evidence suggests the renin-angiotensin system (RAS) plays key immunomodulatory roles. In particular, angiotensin-converting enzyme (ACE) has been shown to play a role in antimicrobial host defense. ACE inhibitors (ACEi) and angiotensin receptor blockers (ARB) are some of the most commonly prescribed medications, especially in patients undergoing invasive surgery. Thus, the current study assessed the immunomodulatory effect of RAS-modulation in a preclinical model of implant infection.

Methods:In vitro antimicrobial effects of ACEi and ARBs were first assessed. C57BL/6J mice subsequently received either an ACEi (lisinopril; 16 mg/kg/day), an ARB (losartan; 30 mg/kg/day), or no treatment. Conditioned mice blood was then utilized to quantify respiratory burst function as well as Staphylococcus aureus Xen36 burden ex vivo in each treatment group. S. aureus infectious burden for each treatment group was then assessed in vivo using a validated mouse model of implant infection. Real-time quantitation of infectious burden via bioluminescent imaging over the course of 28 days post-procedure was assessed. Host response via monocyte and neutrophil infiltration within paraspinal and spleen tissue was quantified by immunohistochemistry for F4/80 and myeloperoxidase, respectively.

Results: Blood from mice treated with an ACEi demonstrated a decreased ability to eradicate bacteria when mixed with Xen36 as significantly higher levels of colony forming units (CFU) and biofilm formation was appreciated ex vivo (p < 0.05). Mice treated with an ACEi showed a higher infection burden in vivo at all times (p < 0.05) and significantly higher CFUs of bacteria on both implant and paraspinal tissue at the time of sacrifice (p < 0.05 for each comparison). There was also significantly decreased infiltration and respiratory burst function of immune effector cells in the ACEi group (p < 0.05).

Conclusion: ACEi, but not ARB, treatment resulted in increased S. aureus burden and impaired immune response in a preclinical model of implant infection. These results suggest that perioperative ACEi use may represent a previously unappreciated risk factor for surgical site infection. Given the relative interchangeability of ACEi and ARB from a cardiovascular standpoint, this risk factor may be modifiable.

Diabetes and COVID-19: A Review

Coronavirus Disease 2019 (COVID-19) is an emerging disease and since its first identification in Wuhan, China, in December 2019, there has been a rapid increase in cases and deaths across the world. COVID-19 has been shown to have an immense impact in infected persons with diabetes, worsening their outcome, especially in elderly, smokers, obese, those having CVD, CKD, poor glycemic control and long duration of diabetes. In this review we summarize the current understanding of `the impact of COVID-19 on diabetes and discusses the pathophysiological mechanisms and management of diabetes and its complication in this scenario.

Efficacy and Safety of Azilsartan Medoxomil and Telmisartan in Hypertensive Patients: A Randomized, Assessor-Blinded Study

BACKGROUND

Few studies have compared the safety and efficacy of azilsartan medoxomil (AZL-M) and telmisartan in hypertensive patients, especially using ambulatory blood pressure monitoring (ABPM).

OBJECTIVE

The objective of this study was to compare the efficacy and safety profile of AZL-M and telmisartan in hypertensive patients using ABPM and clinic blood pressure (BP) monitoring.

MATERIALS AND METHODS

This prospective, randomized, open-label, blinded endpoint, parallel-arm study included 700 patients, aged 18-70 years, with clinic and 24-h mean ambulatory systolic BP (SBP) of 150-180 mmHg and 130-170 mmHg, respectively. They were randomized equally into two groups: Group A received AZL-M 40 mg and Group T received telmisartan 40 mg; the dose was force titrated to 80 mg after 2 weeks if the response rate was not achieved. BP (clinical and ambulatory) was measured after 12 weeks and compared with baseline measurements.

RESULTS

AZL-M significantly reduced the 24-h mean ambulatory SBP (Group A: 112.74 ± 7.58 mmHg; Group T: 113.96 ± 8.52 mmHg; P < 0.0001) and diastolic BP (Group A: 71.39 ± 5.89 mmHg; Group T: 67.29 ± 6.79 mmHg; P < 0.0001) compared with telmisartan at week 12. The clinic SBP significantly decreased in Group A at weeks 4 (-30.69± -0.33 mmHg) and 12 (-39.69± -1.09 mmHg) (for both, P = 0.0001). Dose titration was done in 99 and 128 patients from Group A and Group T, respectively (P = 0.012). Headache was the most common adverse drug reaction (Group A: 21; Group T: 27) and fatigue the least.

CONCLUSION

This study found that AZL-M has greater antihypertensive efficacy than telmisartan, with comparable side effects. In addition, ABPM was shown to be a feasible method for such studies.

ACE overexpression in myeloid cells increases oxidative metabolism and cellular ATP

Angiotensin-converting enzyme (ACE) affects blood pressure. In addition, ACE overexpression in myeloid cells increases their immune function. Using MS and chemical analysis, we identified marked changes of intermediate metabolites in ACE-overexpressing macrophages and neutrophils, with increased cellular ATP (1.7-3.0-fold) and Krebs cycle intermediates, including citrate, isocitrate, succinate, and malate (1.4-3.9-fold). Increased ATP is due to ACE C-domain catalytic activity; it is reversed by an ACE inhibitor but not by an angiotensin II AT1 receptor antagonist. In contrast, macrophages from ACE knockout (null) mice averaged only 28% of the ATP levels found in WT mice. ACE overexpression does not change cell or mitochondrial size or number. However, expression levels of the electron transport chain proteins NDUFB8 (complex I), ATP5A, and ATP5β (complex V) are significantly increased in macrophages and neutrophils, and COX1 and COX2 (complex IV) are increased in macrophages overexpressing ACE. Macrophages overexpressing ACE have increased mitochondrial membrane potential (24% higher), ATP production rates (29% higher), and maximal respiratory rates (37% higher) compared with WT cells. Increased cellular ATP underpins increased myeloid cell superoxide production and phagocytosis associated with increased ACE expression. Myeloid cells overexpressing ACE indicate the existence of a novel pathway in which myeloid cell function can be enhanced, with a key feature being increased cellular ATP.

Cardiac-Specific Overexpression of Catalytically Inactive Corin Reduces Edema, Contractile Dysfunction, and Death in Mice with Dilated Cardiomyopathy

Humans with dilated cardiomyopathy (DCM) and heart failure (HF) develop low levels of corin, a multi-domain, cardiac-selective serine protease involved in natriuretic peptide cleavage and sodium and water regulation. However, experimental restoration of corin levels markedly attenuates HF progression. To determine whether the beneficial effects of corin in HF require catalytic activity, we engineered cardiac overexpression of an enzymatically inactive corin transgene (corin-Tg(i)). On a wild-type (WT) background, corin-Tg(i) had no evident phenotypic effects. However, in a well-established genetic model of DCM, corin-Tg(i)/DCM mice had increased survival (p < 0.01 to 0.001) vs. littermate corin-WT/DCM controls. Pleural effusion (p < 0.01), lung edema (p < 0.05), systemic extracellular free water (p < 0.01), and heart weight were decreased (p < 0.01) in corin-Tg(i)/DCM vs. corin-WT/DCM mice. Cardiac ejection fraction and fractional shortening improved (p < 0.01), while ventricular dilation decreased (p < 0.0001) in corin-Tg(i)/DCM mice. Plasma atrial natriuretic peptide, cyclic guanosine monophosphate, and neprilysin were significantly decreased. Cardiac phosphorylated glycogen synthase kinase-3β (pSer9-GSK3β) levels were increased in corin(i)-Tg/DCM mice (p < 0.01). In summary, catalytically inactive corin-Tg(i) decreased fluid retention, improved contractile function, decreased HF biomarkers, and diminished cardiac GSK3β activity. Thus, the protective effects of cardiac corin on HF progression and survival in experimental DCM do not require the serine protease activity of the molecule.

Novel Therapeutic Approaches Targeting the Renin-Angiotensin System and Associated Peptides in Hypertension and Heart Failure

Despite the success of renin-angiotensin system (RAS) blockade by angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor (AT1R) blockers, current therapies for hypertension and related cardiovascular diseases are still inadequate. Identification of additional components of the RAS and associated vasoactive pathways, as well as new structural and functional insights into established targets, have led to novel therapeutic approaches with the potential to provide improved cardiovascular protection and better blood pressure control and/or reduced adverse side effects. The simultaneous modulation of several neurohumoral mediators in key interconnected blood pressure-regulating pathways has been an attractive approach to improve treatment efficacy, and several novel approaches involve combination therapy or dual-acting agents. In addition, increased understanding of the complexity of the RAS has led to novel approaches aimed at upregulating the ACE2/angiotensin-(1-7)/Mas axis to counter-regulate the harmful effects of the ACE/angiotensin II/angiotensin III/AT1R axis. These advances have opened new avenues for the development of novel drugs targeting the RAS to better treat hypertension and heart failure. Here we focus on new therapies in preclinical and early clinical stages of development, including novel small molecule inhibitors and receptor agonists/antagonists, less conventional strategies such as gene therapy to suppress angiotensinogen at the RNA level, recombinant ACE2 protein, and novel bispecific designer peptides.

In silico analysis of human renin gene-gene interactions and neighborhood topologically associated domains suggests breakdown of insulators contribute to ageing-associated diseases

Three-dimensional chromatin architecture and gene-gene interactions impact gene expression. We assembled this information, in silico, for the human renin gene (REN). We searched for chromatin contacts and boundaries and the locations of super-enhancers that are involved in cell specific differentiation. The REN promoter was connected via RNA polymerase II binding to promoters of 12 neighboring genes on chromosome 1q32.1 over a distance of 762,497 bp. This constitutes a regulatory archipelago. The genes formed 3 topologically associated domains (TADs), as follows: TAD1: ZC3H11A, SNRPE, LINC00303; SOX13; TAD2: ETNK2, REN, KISS1, GOLT1A; TAD3: PLEKHA6, LINC00628, PPP1R15B, PIK3C2B, MDM4. REN in TAD2, was isolated from its neighboring genes in TAD1 and TAD3 by CTCF-binding sites that serve as insulators. TAD1 and TAD3 genes SOX13 and LINC00628 overlapped super-enhancers, known to reside near nodes regulating cell identity, and were co-expressed in various tissues, suggesting co-regulation. REN was also connected with 62 distant genes genome-wide, including the angiotensin II type 1 receptor gene. The findings lead us to invoke the following novel hypothesis. While the REN promoter is isolated from neighboring super-enhancers in most cells by insulators, these insulators break down with cell age to permit the inappropriate expression of REN in non-kidney cells by using the neighboring super-enhancers, resulting in expression in a wider spectrum of tissues, contributing to aging-related immune system dysregulation, cardiovascular diseases and cancers. Research is needed to confirm this hypothesis experimentally.

Angiotensin II and aldosterone in retinal vasculopathy and inflammation

Angiotensin II and aldosterone are the main effectors of the renin-angiotensin aldosterone system (RAAS) and have a central role in hypertension as well as cardiovascular and renal disease. The localization of RAAS components within the retina has led to studies investigating the roles of angiotensin II, aldosterone and the counter regulatory arm of the pathway in vision-threatening retinopathies. This review will provide a brief overview of RAAS components as well as the vascular pathology that develops in the retinal diseases, retinopathy of prematurity, diabetic retinopathy and neovascular age-related macular degeneration. The review will discuss pre-clinical and clinical evidence that modulation of the RAAS alters the development of vasculopathy and inflammation in the aforementioned retinopathies, as well as the emerging role of aldosterone and the mineralocorticoid receptor in central serous chorioretinopathy.

Serum Aldosterone as Predictor of Progression of Coronary Heart Disease in Patients Without Signs of Heart Failure After Acute Myocardial Infarction

Introduction:

In patients with acute myocardial infarction (AMI) early risk assessment of development of complications is of great importance. It is proven that aldosterone level has a major role in progression of cardiovascular pathology.

Aim:

Determination of influence of aldosterone plasma level in the progression of heart disease in patients without signs of heart failure after AMI.

Material and Methods:

Research included 207 patients, hospitalized in the acute phase of myocardial infarction, and who were divided into two groups: 127 patients with no clinical signs of heart failure and 60 patients with heart failure.

Results:

The serum aldosterone concentration was 73.4% higher in the group of decompensated patients, 128 pg/mL (75.4-236 pg/mL) in decompensated and 73.7 pg/mL (42.7 -115.25 pg/mL) in compensated. In the group of compensated patients, changes in aldosterone levels showed a statistically significant effect on the incidence of post-infarction angina (p=0.0001) as well as reinfarction (p=0.009). There is a connection between changes in aldosterone plasma level and positive stress test (p=0.012).

Conclusion:

In patients with AMI, elevated serum aldosterone level can be prognostic factor of the progression of coronary heart disease, development of heart failure, as well of development of post-infarction angina, myocardial reinfarction and pathological finding on the stress test.

Effects of the Angiotensin-Receptor Neprilysin Inhibitor on Cardiac Reverse Remodeling: Meta-Analysis

Background The angiotensin-receptor neprilysin inhibitor (ARNI) sacubitril/valsartan was shown to be superior to the angiotensin-converting enzyme inhibitor enalapril in terms of reducing cardiovascular mortality in the PARADIGM-HF (Prospective Comparison of ARNI with angiotensin-converting enzyme inhibitor to Determine Impact on Global Mortality and Morbidity in Heart Failure) study. However, the impact of ARNI on cardiac reverse remodeling (CRR) has not been established. Methods and Results We conducted a meta-analysis to compare the effects of ARNI versus angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on CRR indices. We searched databases for studies published between 2010 and 2019 that reported CRR indices following ARNI administration. Effect size was expressed as mean difference (MD) with 95% CIs. Twenty studies enrolling 10 175 patients were included. ARNI improved functional capacity in patients with heart failure (HF) and a reduced ejection fraction (EF), including increasing New York Heart Association functional class (MD -0.79, 95% CI -0.86, -0.71) and 6-minute walking distance (MD 27.62 m, 95% CI 15.76, 39.48). ARNI outperformed angiotensin-converting enzyme inhibitors/angiotensin receptor blockers in terms of CRR indices, with striking changes in left ventricular EF, diameter, and volume. However, there were no significant improvements in indices except left ventricular mass index (MD -3.25 g/m2, 95% CI -3.78, -2.72) and left atrial volume (MD -7.20 mL, 95% CI -14.11, -0.29) in HF patients with preserved EF treated with ARNI. Improvements in CRR indices were observed at 3 months and became more significant with longer follow-up to 12 months. The regression equation for the relationship between left ventricular EF and end-diastolic dimension was y=0.041+0.071x+0.045x2+0.006x3. Conclusions ARNI distinctly improved left ventricular size and hypertrophy compared with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers in HF with reduced EF patients, even after short-term follow-up. Patients appeared to benefit more in terms of CRR treated with ARNI as early as possible and for at least 3 months. Further large sample trials are required to determine the effects of ARNI on CRR in HF with preserved EF patients.

Pharmacogenetic Implications of eNOS Polymorphisms (Glu298Asp, T786C, 4b/4a) in Cardiovascular Drug Therapy

Endothelial nitric oxide synthase (NOS3 or eNOS) is the enzyme responsible for the highest production of nitric oxide, with the greatest impact on the cardiovascular system, encoded by the eNOS gene, which presents various polymorphisms. ENOS gene polymorphisms play an important role in the response to drugs affecting nitric oxide (NO) signaling. This review discusses the pharmacogenetic impact of eNOS polymorphisms on the response to drugs affecting NO activity: angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, calcium blockers, beta-blockers, diuretics, phosphodiesterase inhibitors, and statins. The identification of biomarkers that accurately predict particular phenotypes is a challenge that needs additional large studies, in different populations. Efforts should be oriented towards a more accurate evaluation of the effects of eNOS genetic variants on biochemical parameters reflecting eNOS gene expression and enzymatic activity, in different diseases, as well as following drug treatment. This approach will allow for a better understanding of the role of eNOS genetic variants in cardiovascular disease progression and for cardiovascular drug therapy optimization.

Mechanisms impairing blood pressure responses to nitrite and nitrate

Hypertension is a multifactorial disease associated with impaired nitric oxide (NO) production and bioavailability. In this respect, restoring NO activity by using nitrite and nitrate has been considered a potential therapeutic strategy to treat hypertension. This possibility is justified by the understanding that both nitrite and nitrate may be recycled back to NO and also promote the generation of other bioactive species. This process involves a complex biological circuit known as the enterosalivary cycle of nitrate, where this anion is actively taken up by the salivary glands and converted to nitrite by nitrate-reducing bacteria in the oral cavity. Nitrite is then ingested and reduced to NO and other nitroso species under the acid conditions of the stomach, whereas reminiscent nitrite that escapes gastric reduction is absorbed systemically and can be converted into NO by nitrite-reductases in tissues. While there is no doubt that nitrite and nitrate exert antihypertensive effects, several agents can impair the blood pressure responses to these anions by disrupting the enterosalivary cycle of nitrate. These agents include dietary and smoking-derived thiocyanate, antiseptic mouthwash, proton pump inhibitors, ascorbate at high concentrations, and xanthine oxidoreductase inhibitors. In this article, we provide an overview of the physiological aspects of nitrite and nitrate bioactivation and the therapeutic potential of these anions in hypertension. We also discuss mechanisms by which agents counteracting the antihypertensive responses to nitrite and nitrate mediate their effects. These critical aspects should be taken into consideration when suggesting nitrate or nitrite-based therapies to patients.

Potential Medication Treatment According to Pathological Mechanisms in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a vascular disease with high mortality. Because of the lack of effective medications to stop or reverse the progression of AAA, surgical operation has become the most predominant recommendation of treatment for patients. There are many potential mechanisms, including inflammation, smooth muscle cell apoptosis, extracellular matrix degradation, oxidative stress, and so on, involving in AAA pathogenesis. According to those mechanisms, some potential therapeutic drugs have been proposed and tested in animal models and even in clinical trials. This review focuses on recent advances in both pathogenic mechanisms and potential pharmacologic therapies of AAA.

Working Toward an Improved Understanding of Chronic Cardiorenal Syndrome Type 4

Chronic diseases of the heart and of the kidneys commonly coexist in individuals. Certainly combined and persistent heart and kidney failure can arise from a common pathologic insult, for example, as a consequence of poorly controlled hypertension or of severe diffuse arterial disease. However, strong evidence is emerging to suggest that cross talk exists between the heart and the kidney. Independent processes are set in motion when kidney function is chronically diminished, and these processes can have distinct adverse effects on the heart. The complex chronic heart condition that results from chronic kidney disease (CKD) has been termed cardiorenal syndrome type 4. This review will include an updated description of the cardiac morphology in patients who have CKD, an overview of the most likely CKD-sourced culprits for these cardiac changes, and the potential therapeutic strategies to limit cardiac complications in patients who have CKD.

Pharmacokinetics, Pharmacodynamics and Safety of a Single Dose of Imarikiren, a Novel Renin Inhibitor, in Healthy Male Subjects

Imarikiren hydrochloride (TAK-272/SCO-272) is a novel direct renin inhibitor with potential indications for cardiovascular and renal diseases. This phase I study evaluated the pharmacokinetics, pharmacodynamics and safety of a single oral administration of imarikiren in healthy Japanese male subjects. The Dose-Ascending part (double-blind, placebo-controlled, parallel-group design; n = 60) comprised six steps from 5 to 200 mg (n = 8 for imarikiren and n = 2 for placebo per step). The Food Effect part (n = 12) was an open-label, 2 × 2 crossover design with a dose of 50 mg to evaluate the effect of food on the pharmacokinetics and safety of imarikiren. There was a generally linear relationship between dose and area under the plasma concentration-time curve (0 to infinity) or maximum plasma concentration of imarikiren. Food had no clinically significant effect on the exposure of imarikiren. Inhibition of plasma renin activity was rapid and lasted up to 24 hr at all doses. Plasma active renin concentration increased, reaching a maximum at approximately 6 hr, in a nearly dose-dependent manner. Across both study parts, the number of subjects with treatment-emergent adverse events ranged from 0 to 3 per group with no dependency on dose. All treatment-emergent adverse events except two were mild in intensity; there were no serious adverse events or deaths. Single oral administration of imarikiren from 5 to 200 mg was safe and well tolerated. These findings suggest that further clinical development of a once-daily imarikiren regimen is warranted.

Angiotensin-converting enzyme in innate and adaptive immunity

Angiotensin-converting enzyme (ACE) - a zinc-dependent dicarboxypeptidase with two catalytic domains - plays a major part in blood pressure regulation by converting angiotensin I to angiotensin II. However, ACE cleaves many peptides besides angiotensin I and thereby affects diverse physiological functions, including renal development and male reproduction. In addition, ACE has a role in both innate and adaptive responses by modulating macrophage and neutrophil function - effects that are magnified when these cells overexpress ACE. Macrophages that overexpress ACE are more effective against tumours and infections. Neutrophils that overexpress ACE have an increased production of superoxide, which increases their ability to kill bacteria. These effects are due to increased ACE activity but are independent of angiotensin II. ACE also affects the display of major histocompatibility complex (MHC) class I and MHC class II peptides, potentially by enzymatically trimming these peptides. Understanding how ACE expression and activity affect myeloid cells may hold great promise for therapeutic manipulation, including the treatment of both infection and malignancy.

Angiotensin-converting enzyme in innate and adaptive immunity

Angiotensin-converting enzyme (ACE) - a zinc-dependent dicarboxypeptidase with two catalytic domains - plays a major part in blood pressure regulation by converting angiotensin I to angiotensin II. However, ACE cleaves many peptides besides angiotensin I and thereby affects diverse physiological functions, including renal development and male reproduction. In addition, ACE has a role in both innate and adaptive responses by modulating macrophage and neutrophil function - effects that are magnified when these cells overexpress ACE. Macrophages that overexpress ACE are more effective against tumours and infections. Neutrophils that overexpress ACE have an increased production of superoxide, which increases their ability to kill bacteria. These effects are due to increased ACE activity but are independent of angiotensin II. ACE also affects the display of major histocompatibility complex (MHC) class I and MHC class II peptides, potentially by enzymatically trimming these peptides. Understanding how ACE expression and activity affect myeloid cells may hold great promise for therapeutic manipulation, including the treatment of both infection and malignancy.

Within the Brain: The Renin Angiotensin System

For many years, modulators of the renin angiotensin system (RAS) have been trusted by clinicians for the control of essential hypertension. It was recently demonstrated that these modulators have other pleiotropic properties independent of their hypotensive effects, such as enhancement of cognition. Within the brain, different components of the RAS have been extensively studied in the context of neuroprotection and cognition. Interestingly, a crosstalk between the RAS and other systems such as cholinergic, dopaminergic and adrenergic systems have been demonstrated. In this review, the preclinical and clinical evidence for the impact of RAS modulators on cognitive impairment of multiple etiologies will be discussed. In addition, the expression and function of different receptor subtypes within the RAS such as: Angiotensin II type I receptor (AT1R), Angiotensin II type II receptor (AT2R), Angiotensin IV receptor (AT4R), Mas receptor (MasR), and Mas-related-G protein-coupled receptor (MrgD), on different cell types within the brain will be presented. We aim to direct the attention of the scientific community to the plethora of evidence on the importance of the RAS on cognition and to the different disease conditions in which these agents can be beneficial.

The Importance of Model Structure in the Cost-Effectiveness Analysis of Primary Care Interventions for the Management of Hypertension

BACKGROUND

Management of hypertension can lead to significant reductions in blood pressure, thereby reducing the risk of cardiovascular disease. Modeling the course of cardiovascular disease is not without complications, and uncertainty surrounding the structure of a model will almost always arise once a choice of a model structure is defined.

OBJECTIVES

To provide a practical illustration of the impact on the results of cost-effectiveness of changing or adapting model structures in a previously published cost-utility analysis of a primary care intervention for the management of hypertension Targets and Self-Management for the Control of Blood Pressure in Stroke and at Risk Groups (TASMIN-SR).

METHODS

The case study assessed the structural uncertainty arising from model structure and from the exclusion of secondary events. Four alternative model structures were implemented. Long-term cost-effectiveness was estimated and the results compared with those from the TASMIN-SR model.

RESULTS

The main cost-effectiveness results obtained in the TASMIN-SR study did not change with the implementation of alternative model structures. Choice of model type was limited to a cohort Markov model, and because of the lack of epidemiological data, only model 4 captured structural uncertainty arising from the exclusion of secondary events in the case study model.

CONCLUSIONS

The results of this study indicate that the main conclusions drawn from the TASMIN-SR model of cost-effectiveness were robust to changes in model structure and the inclusion of secondary events. Even though one of the models produced results that were different to those of TASMIN-SR, the fact that the main conclusions were identical suggests that a more parsimonious model may have sufficed.

Role of MicroRNA in Endothelial Dysfunction and Hypertension

Purpose of Review

Hypertension is either a cause or a consequence of the endothelial dysfunction and a major risk factor for cardiovascular disease (CVD). In vitro and in vivo studies established that microRNAs (miRNAs) are decisive for endothelial cell gene expression and function in various pathological conditions associated with CVD.

This review provides an overview of the miRNA role in controlling the key connections between endothelial dysfunction and hypertension.

Recent Findings

Herein we summarize the present understanding of mechanisms underlying hypertension and its associated endothelial dysfunction as well as the miRNA role in endothelial cells with accent on the modulation of renin-angiotensin-aldosterone-system, nitric oxide, oxidative stress and on the control of vascular inflammation and angiogenesis in relation to endothelial dysfunction in hypertension. In particular, latest insights in the identification of endothelial-specific microRNAs and their targets are added to the understanding of miRNA significance in hypertension.

Summary

This comprehensive knowledge of the role of miRNAs in endothelial dysfunction and hypertension and of molecular mechanisms proposed for miRNA actions may offer novel diagnostic biomarkers and therapeutic targets for controlling hypertension-associated endothelial dysfunction and other cardiovascular complications.

The role of angiotensin receptor-neprilysin inhibitors in cardiovascular disease-existing evidence, knowledge gaps, and future directions

Although traditional renin-angiotensin system antagonists including angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have revolutionized the treatment of cardiovascular disease (CVD), the pivotal PARADIGM-HF trial demonstrated that sacubitril/valsartan, an angiotensin receptor-neprilysin inhibitor (ARNI), was superior to an angiotensin-converting enzyme inhibitor in reducing cardiovascular morbidity and mortality in patients with heart failure and reduced ejection fraction. However, despite international regulatory approval and strong recommendations in the guidelines, uptake of sacubitril/valsartan has been disappointing. Sacubitril/valsartan is now the focus of a large programme of clinical trials testing the hypothesis that ARNIs may supplant conventional renin-angiotensin system inhibitors across the spectrum of CVD, including hypertension, secondary prevention after myocardial infarction, and heart failure with preserved ejection fraction. This review summarizes the existing evidence, knowledge gaps, and future directions of ARNIs in CVD based on discussions between clinical trialists, industry representatives, and regulatory authorities at the 2016 Global CardioVascular Clinical Trialists Forum in Washington, D.C.