Role of the Renin-Angiotensin-Aldosterone System and Its Pharmacological Inhibitors in Cardiovascular Diseases: Complex and Critical Issues

Preparation of iota-carrageenan@bentonite@4-phenyl-3-thiosemicarbazide ternary hydrogel for adsorption of Losartan potassium and sulfamethoxazole

A rising quantity of drugs has been discharged into the aquatic environment, posing a substantial hazard to public health. In the current work, a novel hydrogel (i.Carr@Bent@PTC), comprised of iota-carrageenan, bentonite, and 4-phenyl-3-thiosemicarbazide, was successfully prepared. The introduction of 4-phenyl-3-thiosemicarbazide and bentonite in iota-carrageenan significantly increased the mechanical strength of iota-carrageenan hydrogel and improved its degree of swelling, which can be attributed to the hydrophilic properties of PTC and Bent. The recorded contact angle was 70.8°, 59.1°, 53.9°, and 34.6° for pristine i.Carr, i.Carr@Bent, and i.Carr@Bent@PTC, respectively. The low contact angle measurement of the Bent and PTC loaded-i.Carr hydrogel was attributed to the hydrophilic Bent and PTC. The ternary i.Carr@Bent@PTC hydrogel demonstrated broad pH adaptability and excellent adsorption capacities for sulfamethoxazole (SMX) and losartan potassium (LP), i.e., 467.61 mg. g-1 and 274.43 mg. g-1 at 298.15 K, respectively. The pseudo-first-order (PSO) model provided a better fit for the adsorption kinetics. The adsorption of SMX and LP can be better explained by employing the Sips and Langmuir isotherm models. As revealed by XPS and FTIR investigations, π-π stacking, complexation, electrostatic interaction, and hydrogen bonding were primarily involved in the adsorption mechanisms.

The Role of Personalized Medicine in Companion Animal Cardiology

Cardiomyopathies remain one of the most common inherited cardiac diseases in both human and veterinary patients. To date, well over 100 mutated genes are known to cause cardiomyopathies in humans with only a handful known in cats and dogs. This review highlights the need and use of personalized one-health approaches to cardiovascular case management and advancement in pharmacogenetic-based therapy in veterinary medicine. Personalized medicine holds promise in understanding the molecular basis of disease and ultimately will unlock the next generation of targeted novel pharmaceuticals and aid in the reversal of detrimental effects at a molecular level.

Targeting the adenosine monophosphate-activated protein kinase signalling pathway by bempedoic acid attenuates Angiotensin II-induced cardiac remodelling in renovascular hypertension in rats

The crosstalk between the renin-angiotensin system and Adenosine monophosphate-activated protein kinase (AMPK) gained significant interest due to their involvement in the pathogenesis of several cardiovascular diseases. Angiotensin II (Ang II) plays a crucial role in developing cardiac remodelling by inducing energy imbalance, inflammation, oxidative and endoplasmic reticulum stress, and transforming growth factor-β (TGF-β)-induced fibrosis. Ang II directly or through extracellular signal-regulated kinase (ERK) activation impairs AMPK signalling with well-known antioxidant, anti-inflammatory, and anti-fibrotic effects.

AIM

This study aimed to investigate the role of bempedoic acid, a novel antihyperlipidemic drug, in attenuating hypertension-induced cardiac remodelling in rats by modulating Ang II-induced damage and activating the AMPK signalling pathway.

METHOD

Sixty adult male Sprague Dawley rats were randomly allocated into the Sham control group, Hypertensive group, Captopril group (30 mg/kg), and Bempedoic acid group (30 mg/kg). Hypertension was induced by left renal artery ligation in all groups except the Sham control group. Treatment with captopril and bempedoic acid started 14 days post-surgy and lasted two weeks. Finally, Hemodynamic measurements and electrocardiographic examination were done followed by heart tissue samples collection for biochemical, histopathological, and immunohistochemical examinations.

KEY FINDINGS

Bempedoic acid preserved the cardiac function and electrocardiogram patterns. It inhibited endoplasmic reticulum stress, exhibited antioxidant activity, and increased endothelial nitric oxide synthase activity. Bempedoic acid interfered with ERK signalling pathways, including nuclear factor-κB and TGF-β, exerting anti-inflammatory and anti-fibrotic effects.

SIGNIFICANCE

These findings indicate the cardioprotective and antihypertrophic activity of bempedoic acid, which are suggested to result from energy-independent AMPK downstream signalling activation.

Pathophysiology of cough with angiotensin-converting enzyme inhibitors: How to explain within-class differences?

Angiotensin converting enzyme inhibitors (ACEi) have consistently demonstrated improved survival and reduced risk of major cardiovascular events, across the spectrum of cardiovascular disease, including hypertension, coronary artery disease, myocardial infarction, and heart failure. The cardioprotective effects of ACEi result from inhibiting the conversion of angiotensin I to angiotensin II, and inhibition of bradykinin degradation. They are generally well tolerated but may cause the onset of a dry cough in some patients. This review presents current evidence on the incidence and mechanisms of cough associated with ACEi use, and then considers how to manage ACEi-related cough in clinical practice. The incidence of ACEi-induced cough in the published literature varies widely due to heterogeneity in the source data and lack of adequate controls. Incidence also varies among individual ACEi with agents such as perindopril, which has a high tissue ACE affinity, associated with a lower rate of cough. Evidence from real-world studies shows that the incidence of ACEi-associated cough is lower than rates reported in clinical trials. Patients who experience any dry cough are often switched to angiotensin- receptor blockers or other classes of antihypertensive drugs, regardless of cough severity. To avoid inappropriate discontinuation of ACEi in clinical practice, an alternative approach in patients with persistent cough is to perform a challenge/re-challenge to determine if re-introduction of ACEi is associated with recurrence of symptoms. Incidence of cough should not be considered a class effect for ACEi, and the patient may benefit by a switch from one ACEi to another. Every effort should be made to enable patients to continue ACEi therapy to reduce adverse cardiovascular outcomes and improve survival.

Effect of bempedoic acid on angiotensin-II induced hypertension and vascular tissue remodelling in renal hypertensive rats through AMPK multiple signalling pathways modulation

Angiotensin II (Ang II), the effector of the renin-angiotensin system (RAS), is a key player in the pathogenesis of chronic hypertension, accompanied by vascular tissue resistance, remodelling, and damage. Chronic activation of Ang II receptor 1 (AT-1R) impairs multiple cellular targets implicated in cellular protection and survival, including adenosine Monophosphate-activated protein kinase (AMPK) signalling. In addition, it induces oxidative damage, endoplasmic reticulum (ER) stress, and fibrotic changes in resistance vessels. Our study investigated the antihypertensive and antifibrotic effects of bempedoic acid, a first-in-class antihyperlipidemic drug that targets adenosine triphosphate-citrate lyase enzyme to inhibit cholesterol synthesis. We also studied the modulation of multiple AMPK signalling pathways by bempedoic acid in a chronic hypertension model in rats. Sixty male Sprague-Dawley rats were divided into four groups: sham group, hypertensive group, standard captopril group, and bempedoic treated group. All groups underwent left renal artery ligation except the sham group. Fourteen days post-surgery, captopril and bempedoic acid were administered with a dose of 30 mg/kg/day orally to captopril-standard and bempedoic acid-treated groups for two weeks, respectively. In mesenteric resistance arteries, bempedoic acid activated AMPK energy independently and augmented AMPK multiple cellular targets to adapt to Ang II-induced cellular stress. It exerted antioxidant activity, increased endothelial nitric oxide synthase, and reversed the ER stress. Bempedoic acid maintained vascular integrity and prevented vascular remodelling by inhibiting extracellular signal-regulated kinase (ERK)/transforming growth factor-β fibrotic pathway. These effects were reflected in the improved hemodynamic measurements.

Development of a DHA-Losartan hybrid as a potent inhibitor of multiple pathway-induced platelet aggregation

Despite the scientific progression in the prevention and treatment of cardiovascular diseases (CVDs) they remain the leading cause of mortality and disability worldwide. The classic treatment involves the simultaneous dosing of two antiplatelet drugs, aspirin and clopidogrel/prasugrel. However, besides drug resistance, severe side effects have been also manifested including acute bleeding and toxicity. Thus, new therapeutic agents with enhanced efficacy and diminished side effects are of importance. Towards this end, omega-3 (ω-3) fatty acids have demonstrated potent efficacy against CVDs through inhibiting platelet aggregation that bears a pivotal role in atherothrombosis. Another factor that displays a critical role in the pathogenesis of cardiovascular diseases is the renin-angiotensin system (RAS), and especially the AT₁R blocker losartan that has been reported to exert antiplatelet activity mediated by this receptor. Along these lines, we envisaged developing a molecular hybrid consisted of docosahexaenoic acid (ω-3 fatty acid) and losartan, that could exert a notable antiplatelet effect against CVDs. The design and synthesis of the new DHA-losartan hybrid, designated DHA-L, bestowed with the additive properties of the parent compounds, is reported. In silico studies were first exploited to validate the potential of DHA-L to retain losartan's ability to bind AT₁R. The antiplatelet activity of DHA-L was evaluated against in vitro platelet aggregation induced by several platelet agonists. Notably, the hybrid illustrated a pleiotropic antiplatelet profile inhibiting platelet aggregation through multiple platelet activation pathways including P2Y12, PAR-1 (Protease-Activated Receptor-1), PAF (Platelet Activating Factor), COX-1 (cyclooxygenase-1) and collagen receptors. The stability of DHA-L in human plasma and in a wide range of pH values was also evaluated over time using an HPLC protocol. The hybridization approach described herein could pave the way for the development of novel potent multitargeted therapeutics with enhanced antiplatelet profile.Communicated by Ramaswamy H. Sarma.

Population-based pattern of medication use and prevalence of polypharmacy among patients with cardiovascular diseases: results of the Pars cohort study from Iran

Background

Polypharmacy in patients with cardiovascular diseases (CVDs) has been linked to several adverse outcomes. This study aimed to investigate the pattern of medication use and prevalence of polypharmacy among CVDs patients in Iran.

Method

We used the baseline data of the Pars cohort study (PCS). The participants were asked to bring their medication bags; then, the medications were classified using the Anatomical Therapeutic Chemical classification. Polypharmacy was defined as using five or more medications concurrently. Poisson regression modeling was applied. The adjusted prevalence ratios (PR) and its 95% confidence interval (CI) were estimated.

Results

Totally, 9262 participants were enrolled in the PCS, of whom 961 had CVDs. The prevalence of polypharmacy in participants with and without CVDs was 38.9% and 7.1%, respectively. The highest prevalence of polypharmacy (51.5%) was among obese patients. Abnormal waist-hip ratio (PR: 2.79; 95% CI 1.57–4.94), high socioeconomic status (PR: 1.65; 95% CI 1.07–2.54), tobacco-smoking (PR: 1.35; 95% CI 1.00–1.81), patients with more than three co-morbidities (PR: 1.41; 95% CI 1.30–1.53), high physical activity (PR: 0.66; 95% CI 0.45–0.95), use of opiate ever (PR: 0.46; 95% CI 0.26–0.82), and healthy overweight subjects (PR: 0.22; 95% CI 0.12–0.39) were associated with polypharmacy. Cardiovascular drugs (76.1%), drugs acting on blood and blood-forming organs (50.4%), and alimentary tract and metabolism drugs (33.9%) were the most frequently used drugs. Agents acting on the renin-angiotensin system were the mostly used cardiovascular system drugs among men and those above 60 years old, while beta-blocking agents were mostly prevalent among cardiovascular system drugs in women with CVDs.

Conclusion

Given the high prevalence of polypharmacy among CVDs patients, and subsequent complications, programs to educate both physicians and patients to prevent this issue is crucial.

Potential Use of Some Indonesian Plants to Inhibits Angiotensin-converting Enzyme In Vitro

BACKGROUND: Some Indonesian plants, such as Vaccinium varingiaefolium Miq., Plectranthus scutellarioides (L.) R.Br., Syzygium myrtifolium Walp., and Eclipta prostrata (L.) L., are rich of flavonoid and anthocyanin. Flavonoid, flavan-3-ol, quercetin, anthocyanin, and tannin compounds can reduce systemic vascular resistance because they cause vasodilation and are thought to be able to influence the function of angiotensin-converting enzyme (ACE) and inhibit ACE activity, which plays an important role in the process of hypertension. AIM: This study aims to determine the potential of some Indonesian plants to inhibit ACE activity. METHODS: Testing of ACE inhibitory activity is carried out by the hippuric acid compounds formed as a result of the reaction between the substrate and the enzyme, then measured spectrophotometrically. The inhibitory and IC50 values of each test sample were compared with the positive control of Captopril. RESULTS: The four plant extracts contained secondary metabolites, such as flavonoids, tannins, saponins, quinones, steroids, triterpenoids, and essential oils. Ethanol extract of V. varingiaefolium Miq., P. scutellarioides (L.) R.Br., S. myrtifolium Walp., and E. prostrata (L.) L. each had an IC50 value of ACE inhibition activity of 131.4 ppm, 206. 7 ppm, 151.2 ppm, and 196.0 ppm. The IC50 value of the Captopril with inhibition of ACE activity is 11.1 ppm. CONCLUSION: This study shows that some Indonesian plants have the activity to inhibit the ACE and potential antihypertensive drug candidates with ACE inhibitory activity.

Correlation between Angiotensin Serum Levels and Very-Low-Frequency Spectral Power of Heart Rate Variability during Hemodialysis

Cardiovascular regulatory mechanisms that fail to compensate for ultrafiltration and cause hypovolemia during hemodialysis (HD) are not completely understood. This includes the interaction between the autonomic nervous system and the biochemistry that regulates blood pressure and modulates cardiac activity and vascular tone in response to hypovolemia in patients treated with HD. The objective was to evaluate the association of spectral indices of heart rate variability (HRV) with serum levels of angiotensin II, angiotensin 1–7, nitric oxide and total antioxidant capacity during HD. Electrocardiographic records were obtained from 20 patients during HD (3 h), from which HRV data and spectral power data in the very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands were generated. Three blood samples per patient were collected during HD (0.0, 1.5, 3.0 h) to determine the levels of biomarkers involved in the pressor response during HD. Angiotensin II had a positive correlation with VLF (r = 0.390) and with LF/HF (r = 0.359) and a negative correlation with LF (r = −0.262) and HF (r = −0.383). There were no significant correlations between HRV and the other biomarkers. These results suggest that during HD, VLF could reflect the serum levels of angiotensin II, which may be associated with the autonomic response to HD.

Diminazene aceturate mitigates cardiomyopathy by interfering with renin-angiotensin system in a septic rat model

Background

There were limited studies investigating treatments of septic cardiomyopathy (SCM), which is a common complication during sepsis. A septic rat model created by cecal ligation and puncture (CLP) was used to investigate the effects of diminazene aceturate (DIZE) in SCM.

Methods

A total of 151 Wistar rats were randomly assigned into the sham, CLP, or CLP + DIZE group. Data evaluated postoperatively at 6, 12, 24, and 48 hours included: cardiac function; plasma concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6, angiotensin-(1–7) [Ang-(1–7)], angiotensin II (AngII), troponin I, and brain natriuretic peptide; expression levels of myocardial Ang-(1–7), angiotensin-converting enzyme (ACE), ACE2, and angiotensin type 1 and Mas receptors; and histological changes.

Results

We found that the CLP + DIZE group had a lower mortality compared to the CLP group (38.5% versus 61.5%) within 48 h postoperatively, although without statistical significance. In contrast to the sham group, the CLP group had decreased cardiac functions, increased myocardial injuries, and higher TNF-α levels, which were ameliorated in the CLP + DIZE group. Furthermore, administration of DIZE could reverse the decreases of myocardial Ang-(1–7) and ACE2 expressions in the CLP group, which finally minimized the myocardial microstructure disruptions.

Conclusions

It was concluded that DIZE could mitigate the development of SCM and preserve cardiac function during sepsis possibly by interfering with the renin-angiotensin system through promoting myocardial ACE2 expression and restoring local Ang-(1–7) levels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00584-4.

Insights Into Vascular Anomalies, Cancer, and Fibroproliferative Conditions: The Role of Stem Cells and the Renin-Angiotensin System

Cells exhibiting embryonic stem cell (ESC) characteristics have been demonstrated in vascular anomalies (VAs), cancer, and fibroproliferative conditions, which are commonly managed by plastic surgeons and remain largely unsolved. The efficacy of the mTOR inhibitor sirolimus, and targeted therapies that block the Ras/BRAF/MEK/ERK1/2 and PI3KCA/AKT/mTOR pathways in many types of cancer and VAs, further supports the critical role of ESC-like cells in the pathogenesis of these conditions. ESC-like cells in VAs, cancer, and fibroproliferative conditions express components of the renin-angiotensin system (RAS) – a homeostatic endocrine signaling cascade that regulates cells with ESC characteristics. ESC-like cells are influenced by the Ras/BRAF/MEK/ERK1/2 and PI3KCA/AKT/mTOR pathways, which directly regulate cellular proliferation and stemness, and interact with the RAS at multiple points. Gain-of-function mutations affecting these pathways have been identified in many types of cancer and VAs, that have been treated with targeted therapies with some success. In cancer, the RAS promotes tumor progression, treatment resistance, recurrence, and metastasis. The RAS modulates cellular invasion, migration, proliferation, and angiogenesis. It also indirectly regulates ESC-like cells via its direct influence on the tissue microenvironment and by its interaction with the immune system. In vitro studies show that RAS inhibition suppresses the hallmarks of cancer in different experimental models. Numerous epidemiological studies show a reduced incidence of cancer and improved survival outcomes in patients taking RAS inhibitors, although some studies have shown no such effect. The discovery of ESC-like cells that express RAS components in infantile hemangioma (IH) underscores the paradigm shift in the understanding of its programmed biologic behavior and accelerated involution induced by β-blockers and angiotensin-converting enzyme inhibitors. The findings of SOX18 inhibition by R-propranolol suggests the possibility of targeting ESC-like cells in IH without β-adrenergic blockade, and its associated side effects. This article provides an overview of the current knowledge of ESC-like cells and the RAS in VAs, cancer, and fibroproliferative conditions. It also highlights new lines of research and potential novel therapeutic approaches for these unsolved problems in plastic surgery, by targeting the ESC-like cells through manipulation of the RAS, its bypass loops and converging signaling pathways using existing low-cost, commonly available, and safe oral medications.

Angiotensin-Converting Enzyme (ACE) Inhibitory Activity and Mechanism Analysis of N-(1-Deoxy-d-fructos-1-yl)-histidine (Fru-His), a Food-Derived Amadori Compound

N-(1-Deoxy-d-fructos-1-yl)-histidine (Fru-His), one of the Amadori compounds, widely presents in processed foods, and its potential functional activities have attracted extensive attention in recent years. In this work, the angiotensin-converting enzyme (ACE) inhibitory activity and mechanism of Fru-His were investigated. The IC₅₀ value of Fru-His was 0.150 ± 0.019 mM, and there was no obvious degradation of Fru-His after digestion simulation, showing that Fru-His has good ACE inhibition and digestive stability. Fru-His was a competitive inhibitor according to the enzyme inhibition kinetic analysis. The interaction between ACE and Fru-His occurred spontaneously mainly through hydrogen bonding, and the process was accompanied by fluorescence quenching and the alteration of the secondary structure of ACE. The molecular docking data supported the above results. Fru-His was attached to ACE's S1 active pocket through hydrogen bonds and interacted with zinc ions in active sites. The present study demonstrates that food-derived Fru-His has the potential to relieve hypertension.

Quercetin Attenuates Cardiac Hypertrophy by Inhibiting Mitochondrial Dysfunction Through SIRT3/PARP-1 Pathway

Cardiac hypertrophy is an important characteristic in the development of hypertensive heart disease. Mitochondrial dysfunction plays an important role in the pathology of cardiac hypertrophy. Recent studies have shown that sirtuin 3 (SIRT3)/poly (ADP-ribose) polymerase-1 (PARP-1) pathway modulation inhibits cardiac hypertrophy. Quercetin, a natural flavonol agent, has been reported to attenuate cardiac hypertrophy. However, the molecular mechanism is not completely elucidated. In this study, we aimed to explore the mechanism underlying the protective effect of quercetin on cardiac hypertrophy. Spontaneously hypertensive rats (SHRs) were treated with quercetin (20 mg/kg/d) for 8 weeks to evaluate the effects of quercetin on blood pressure and cardiac hypertrophy. Additionally, the mitochondrial protective effect of quercetin was assessed in H9c2 cells treated with Ang II. SHRs displayed aggravated cardiac hypertrophy and fibrosis, which were attenuated by quercetin treatment. Quercetin also improved cardiac function, reduced mitochondrial superoxide and protected mitochondrial structure in vivo. In vitro, Ang II increased the mRNA level of hypertrophic markers including atrial natriuretic factor (ANF) and β-myosin heavy chain (β-MHC), whereas quercetin ameliorated this hypertrophic response. Moreover, quercetin prevented mitochondrial function against Ang II induction. Importantly, mitochondrial protection and PARP-1 inhibition by quercetin were partly abolished after SIRT3 knockdown. Our results suggested that quercetin protected mitochondrial function by modulating SIRT3/PARP-1 pathway, contributing to the inhibition of cardiac hypertrophy.

Whey-Derived Peptides at the Heart of the COVID-19 Pandemic

The renin-angiotensin system (RAS) is a key regulator of blood pressure and hypertension. Angiotensin-converting enzyme 2 (ACE2) and angiotensin-converting enzyme I (ACE) are two main components of the RAS that play a major role in blood pressure homeostasis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses ACE2 as a receptor to enter cells. Despite some controversies, numerous studies have reported a significant association between the use of ACE inhibitors and reduced risk of COVID-19. In our previous studies, we produced and identified peptide sequences present in whey hydrolysates exhibiting high ACE inhibitory activity. Therefore, the aim of this work is to obtain an improved understanding of the function of these natural peptides as RAS inhibitors and investigate their potential therapeutic role in the COVID-19 pandemic. The molecular interactions between peptides IPP, LIVTQ, IIAE, LVYPFP, and human ACE2 were assessed by employing a molecular docking approach. The results show that natural whey-derived peptides have a dual inhibitory action against both ACE and ACE2. This dual activity distinguishes these ACE inhibitory peptides from synthetic drugs, such as Captopril and Lisinopril which were not shown to inhibit ACE2 activity, and may represent a potential strategy in the treatment of COVID-19.

Angiotensin II up-regulates sodium-glucose co-transporter 2 expression and SGLT2 inhibitor attenuates Ang II-induced hypertensive renal injury in mice

Clinical trials indicate that sodium/glucose co-transporter 2 (SGLT2) inhibitors (SGLT2i) improve kidney function, yet, the molecular regulation of SGLT2 expression is incompletely understood. Here, we investigated the role of the intrarenal renin-angiotensin system (RAS) on SGLT2 expression. In adult non-diabetic participants in the Nephrotic Syndrome Study Network (NEPTUNE, n=163), multivariable linear regression analysis showed SGLT2 mRNA was significantly associated with angiotensinogen (AGT), renin, and angiotensin-converting enzyme (ACE) mRNA levels (P<0.001). In vitro, angiotensin II (Ang II) dose-dependently stimulated SGLT2 expression in HK-2, human immortalized renal proximal tubular cells (RPTCs); losartan and antioxidants inhibited it. Sglt2 expression was increased in transgenic (Tg) mice specifically overexpressing Agt in their RPTCs, as well as in WT mice with a single subcutaneous injection of Ang II (1.44 mg/kg). Moreover, Ang II (1000 ng/kg/min) infusion via osmotic mini-pump in WT mice for 4 weeks increased systolic blood pressure (SBP), glomerulosclerosis, tubulointerstitial fibrosis, and albuminuria; canaglifozin (Cana, 15 mg/kg/day) reversed these changes, with the exception of SBP. Fractional glucose excretion (FeGlu) was higher in Ang II+Cana than WT+Cana, whereas Sglt2 expression was similar. Our data demonstrate a link between intrarenal RAS and SGLT2 expression and that SGLT2i ameliorates Ang II-induced renal injury independent of SBP.

Angiotensin II and angiotensin 1-7: which is their role in atrial fibrillation?

Atrial fibrillation (AF) is a significant cause of morbidity and mortality as well as a public health burden considering the high costs of AF-related hospitalizations. Pre-clinical and clinical evidence showed a potential role of the renin angiotensin system (RAS) in the etiopathogenesis of AF. Among RAS mediators, angiotensin II (AII) and angiotensin 1-7 (A1-7) have been mostly investigated in AF. Specifically, the stimulation of the pathway mediated by AII or the inhibition of the pathway mediated by A1-7 may participate in inducing and sustaining AF. In this review, we summarize the evidence showing that both RAS pathways may balance the onset of AF through different biological mechanisms involving inflammation, epicardial adipose tissue (EAT) accumulation, and electrical cardiac remodeling. EAT is a predictor for AF as it may induce its onset through direct (infiltration of epicardial adipocytes into the underlying atrial myocardium) and indirect (release of inflammatory adipokines, the stimulation of oxidative stress, macrophage phenotype switching, and AF triggers) mechanisms. Classic RAS blockers such as angiotensin converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARB) may prevent AF by affecting the accumulation of the EAT, representing a useful therapeutic strategy for preventing AF especially in patients with heart failure and known left ventricular dysfunction. Further studies are necessary to prove this benefit in patients with other cardiovascular diseases. Finally, the possibility of using the A1-7 or ACE2 analogues, to enlarge current therapeutic options for AF, may represent an important field of research.

Association of serum uromodulin with mortality and cardiovascular disease in the elderly-the Cardiovascular Health Study

BACKGROUND

Uromodulin (UMOD) is released by renal tubular cells into the serum (sUMOD) and urine. Lower urine UMOD has been linked to mortality and cardiovascular disease but much less is known about sUMOD. We evaluated the association of sUMOD with these outcomes in community-dwelling older adults.

METHODS

We measured sUMOD in a random subcohort of 933 participants enrolled in the Cardiovascular Health Study. The associations of sUMOD with all-cause mortality, incident heart failure (HF) and incident cardiovascular disease (CVD; myocardial infarction, stroke and mortality due to coronary disease or stroke) were evaluated using multivariable Cox regression, adjusting for study participants' demographics, estimated glomerular filtration rate (eGFR), albuminuria and CVD risk factors. Generalized additive models with splines were used to address the functional form of sUMOD with outcomes. Due to nonlinear associations of sUMOD with all outcomes, 2.5% of the values on either end of the sUMOD distribution were excluded from the analyses, limiting the range of sUMOD to 34.3-267.1 ng/mL.

RESULTS

The mean age was 78 ± 5 years, 40% were male, sUMOD level was 127 ± 64 ng/mL, eGFR was 63 mL/min/1.73 m2 and 42% had CKD defined as eGFR <60 mL/min/1.73 m2. Patients in the lower sUMOD quartiles had lower eGFR and higher albuminuria (P < 0.01, respectively). During a median follow-up of 9.9 years, 805 patients died, 283 developed HF and 274 developed CVD. In multivariable analysis, higher sUMOD was significantly associated with a lower hazard for mortality {hazard ratio [HR] 0.89 [95% confidence interval (CI) 0.80-0.99] per 1 standard deviation (SD) higher sUMOD}, CVD [HR 0.80 (95% CI 0.67-0.96)] and the composite endpoint [HR 0.88 (95% CI 0.78-0.99)]; the association with HF was not statistically significant [HR 0.84 (95% CI 0.70-1.01)].

CONCLUSION

Higher sUMOD is independently associated with a lower risk for mortality and CVD in older adults.

Flow-mediated outward arterial remodeling in aging

The present review focuses on the effect of aging on flow-mediated outward remodeling (FMR) via alterations in estrogen metabolism, oxidative stress and inflammation. In ischemic disorders, the ability of the vasculature to adapt or remodel determines the quality of the recovery. FMR, which has a key role in revascularization, is a complex phenomenon that recruits endothelial and smooth muscle cells as well as the immune system. FMR becomes progressively less with age as a result of an increase in inflammation and oxidative stress, in part of mitochondrial origin. The alteration in FMR is greater in older individuals with risk factors and thus the therapy cannot merely amount to exercise with or without a mild vasodilating drug. Interestingly, the reduction in FMR occurs later in females. Estrogen and its alpha receptor (ERα) play a key role in FMR through the control of dilatory pathways including the angiotensin II type 2 receptor, thus providing possible tools to activate FMR in older subjects although only experimental data is available. Indeed, the main issue is the reversibility of the vascular damage induced over time, and to date promoting prevention and limiting exposure to the risk factors remain the best options in this regard.

Blood Pressure Target Achievement Under Monotheraphy: A Real-Life Appraisal

INTRODUCTION

Despite hypertension guidelines suggest that the most effective treatment strategy to improve blood pressure (BP) target achievement is to implement the use of combination treatment, monotherapy is still widely used in the clinical practice of hypertension.

AIM

To investigate BP control under monotherapy in the setting of real-life.

METHODS

We extracted data from a medical database of adult outpatients who were referred to the Hypertension Unit, Sant'Andrea Hospital, Rome (IT), including anthropometric data, CV risk factors and comorbidities, presence or absence of antihypertensive therapy and concomitant medications. Among treated hypertensive patients, we identified only those under single antihypertensive agent (monotherapy). Office BP treatment targets were defined according to 2018 ESC/ESH guidelines as: (a) < 130/80 mmHg in individuals aged 18-65 years; (b) < 140/80 mmHg in those aged > 65 years.

RESULTS

From an overall sample of 7797 records we selected 1578 (20.2%) hypertensive outpatients (47.3% female, age 59.5 ± 13.6 years, BMI 26.6 ± 4.4 kg/m²) treated with monotherapies, among whom 30.5% received ACE inhibitors, 37.7% ARBs, 15.8% beta-blockers, 10.6% CCBs, 3.0% diuretics, and 2.0% alpha-blockers. 36.6% of these patients reached the conventional clinic BP goal of < 140/90 mmHg, whilst the 2018 European guidelines BP treatment targets were fulfilled only in 14.0%. In particular, 10.2% patients aged 18-65 years and 20.4% of those aged > 65 years achieved the recommended BP goals. All these proportions results significantly lower than those achieved with dual (18.2%) or triple (22.2%) combination therapy, though higher than those obtained with life-style changes (10.8%). Proportions of patients on monotherapies with normal home and 24-h BP levels were 22.0% and 30.2%, respectively, though only 5.2% and 7.3% of these patients achieved sustained BP control, respectively. Ageing and dyslipidaemia showed significant and independent positive predictive value for the achievement of the recommended BP treatment targets, whereas European SCORE resulted a negative and independent predictor in outpatients treated with monotherapies.

CONCLUSIONS

Our data showed a persistent use of monotherapy in the clinical practice, though with unsatisfactory BP control, especially in light of the BP treatment targets suggested by the last hypertension guidelines.

Zi Shen Huo Luo Formula Prevents Aldosterone-Induced Cardiomyocyte Hypertrophy and Cardiac Fibroblast Proliferation by Regulating the Striatin-Mediated MR/EGFR/ERK Signaling Pathway

Inappropriate activation of the renin-angiotensin-aldosterone system (RAAS) is an important factor in the development of hypertension. Excessive aldosterone can lead to myocardial extracellular matrix collagen proliferation, fibrosis, and cardiomyocyte hypertrophy and aggravate maladaptive remodeling. The results of our previous clinical and animal experiments suggested that Zi Shen Huo Luo Formula (ZSHLF) combined with perindopril can effectively control the process of left ventricular hypertrophy (LVH). The purpose of this study was to investigate whether ZSHLF-treated serum inhibits the membrane localization of the striatin-mediated mineralocorticoid receptor (MR) and affects MR-mediated nongenomic effects and the downstream epidermal growth factor receptor (EGFR)/extracellular regulated kinase (ERK) signaling pathways, thereby improving aldosterone-induced myocardial remodeling. Serum containing ZSHLF was prepared and used to treat rat cardiomyocytes and cardiac fibroblasts in vitro after aldosterone induction and striatin knockdown by small interfering RNA (siRNA). Cell-based assays were carried out to determine the cardiomyocyte surface area and assess the proliferation rate and hydroxyproline secretion of cardiac fibroblasts. Quantitative real-time PCR (qRT-PCR), immunoprecipitation (IP), and Western blotting were performed to evaluate the striatin-mediated MR/EGFR/ERK signaling pathway. In the present study, ZSHLF attenuated the aldosterone-induced hypertrophy of cardiomyocytes and inhibited the proliferation and collagen synthesis of cardiac fibroblasts. ZSHLF also reduced striatin mRNA expression and inhibited striatin and MR binding, membrane MR protein expression, and EGFR and ERK1/2 phosphorylation. Furthermore, after striatin silencing with siRNA, some of the effects of ZSHLF were not changed significantly. In conclusion, ZSHLF inhibits the downstream EGFR/ERK signaling pathway by blocking the striatin-mediated membrane localization of MR, which may be an important molecular mechanism by which ZSHLF improves aldosterone-induced myocardial remodeling.

Insulin Resistance the Hinge Between Hypertension and Type 2 Diabetes

Epidemiological studies have documented a high incidence of diabetes in hypertensive patients.Insulin resistance is defined as a less than expected biologic response to a given concentration of the hormone and plays a pivotal role in the pathogenesis of diabetes. However, over the last decades, it became evident that insulin resistance is not merely a metabolic abnormality, but is a complex and multifaceted syndrome that can also affect blood pressure homeostasis. The dysregulation of neuro-humoral and neuro-immune systems is involved in the pathophysiology of both insulin resistance and hypertension. These mechanisms induce a chronic low grade of inflammation that interferes with insulin signalling transduction. Molecular abnormalities associated with insulin resistance include the defects of insulin receptor structure, number, binding affinity, and/or signalling capacity. For instance, hyperglycaemia impairs insulin signalling through the generation of reactive oxygen species, which abrogate insulin-induced tyrosine autophosphorylation of the insulin receptor. Additional mechanisms have been described as responsible for the inhibition of insulin signalling, including proteasome-mediated degradation of insulin receptor substrate 1/2, phosphatase-mediated dephosphorylation and kinase-mediated serine/threonine phosphorylation of both insulin receptor and insulin receptor substrates. Insulin resistance plays a key role also in the pathogenesis and progression of hypertension-induced target organ damage, like left ventricular hypertrophy, atherosclerosis and chronic kidney disease. Altogether these abnormalities significantly contribute to the increase the risk of developing type 2 diabetes.

AT2R agonist NP-6A4 mitigates aortic stiffness and proteolytic activity in mouse model of aneurysm

Clinical and experimental studies show that angiotensin II (AngII) promotes vascular pathology via activation of AngII type 1 receptors (AT1Rs). We recently reported that NP-6A4, a selective peptide agonist for AngII type 2 receptor (AT2R), exerts protective effects on human vascular cells subjected to serum starvation or doxorubicin exposure. In this study, we investigated whether NP-6A4-induced AT2R activation could mitigate AngII-induced abdominal aortic aneurism (AAA) using AngII-treated Apoe^-/- mice. Male Apoe^-/- mice were infused with AngII (1 µg/kg/min) by implanting osmotic pumps subcutaneously for 28 days. A subset of mice was pre-treated subcutaneously with NP-6A4 (2.5 mg/kg/day) or vehicle for 14 days prior to AngII, and treatments were continued for 28 days. NP-6A4 significantly reduced aortic stiffness of the abdominal aorta induced by AngII as determined by ultrasound functional analyses and histochemical analyses. NP-6A4 also increased nitric oxide bioavailability in aortic tissues and suppressed AngII-induced increases in monocyte chemotactic protein-1, osteopontin and proteolytic activity of the aorta. However, NP-6A4 did not affect maximal intraluminal aortic diameter or AAA incidences significantly. These data suggest that the effects of AT2R agonist on vascular pathologies are selective, affecting the aortic stiffness and proteolytic activity without affecting the size of AAA.

Relationship between intrarenal renin-angiotensin activity and re-hospitalization in patients with heart failure with reduced ejection fraction

OBJECTIVE

Heart failure (HF) is a clinical syndrome resulting from structural or functional damages. Although clinical trials have shown that the plasma renin-angiotensin system (RAS) activation decreases HF functional status and increases hospitalization for HF patients, the effect of intrarenal RAS activity is still unknown. In this study, we investigated the relationship between the New York Heart Association (NYHA) class, duration, and number of hospitalizations in the previous year and urinary angiotensinogen (UAGT) in patients with HF with reduced ejection fraction (HFrEF).

METHODS

This study included 85 patients who had an ejection fraction of <40% and were receiving optimal medical treatment. Among these, 22 were excluded from the study for various reasons. Demographically and biochemically, the remaining 63 patients were compared according to the NYHA functional classes and re-hospitalization status.

RESULTS

When the groups were compared in terms of N-terminal pro-B-type natriuretic peptide (NT-proBNP), UAGT, and high-sensitivity C-reactive protein (Hs-CRP), it was found that these parameters were significantly higher in patients who were hospitalized more than two times in the previous year [p<0.001; p=0.007; p<0.001, respectively]. There was a significant correlation between number of hospitalizations and NT-proBNP (r=0.507, p<0.001), Hs-CRP (r=0.511, p<0.001), hemoglobin (r=-0.419, p=0.001), serum sodium (r=-0.26, p=0.04), and systolic blood pressure (r=-0.283, p=0.02). When the independence of multiple correlations was assessed using multiple linear regression analysis, NT-proBNP, Hs-CRP, and hemoglobin levels were independent predictors of re-hospitalization, but this was not the same for UAGT.

CONCLUSION

Although UAGT levels are high in patients with poor NYHA functional class and repeated hospitalizations, this marker is not valuable for predicting repeated hospitalization in patients with HFrEF.

The Plethora of Angiotensin-Converting Enzyme-Processed Peptides in Mouse Plasma

Angiotensin-converting enzyme (ACE) converts angiotensin I into the potent vasoconstrictor angiotensin II, which regulates blood pressure. However, ACE activity is also essential for other physiological functions, presumably through processing of peptides unrelated to angiotensin. The goal of this study was to identify novel natural substrates and products of ACE through a series of mass-spectrometric experiments. This included comparing the ACE-treated and untreated plasma peptidomes of ACE-knockout (KO) mice, validation with select synthetic peptides, and a quantitative in vivo study of ACE substrates in mice with distinct genetic ACE backgrounds. In total, 244 natural peptides were identified ex vivo as possible substrates or products of ACE, demonstrating high promiscuity of the enzyme. ACE prefers to cleave substrates with Phe or Leu at the C-terminal P2' position and Gly in the P6 position. Pro in P1' and Iso in P1 are typical residues in peptides that ACE does not cleave. Several of the novel ACE substrates are known to have biological activities, including a fragment of complement C3, the spasmogenic C3f, which was processed by ACE ex vivo and in vitro. Analyses with N-domain-inactive (NKO) ACE allowed clarification of domain selectivity toward substrates. The in vivo ACE-substrate concentrations in WT, transgenic ACE-KO, NKO, and CKO mice correspond well with the in vitro observations in that higher levels of the ACE substrates were observed when the processing domain was knocked out. This study highlights the vast extent of ACE promiscuity and provides a valuable platform for further investigations of ACE functionality.

Ethyl Acetate Fraction of Lannea microcarpa Engl. and K. Krause (Anacardiaceae) Trunk Barks Corrects Angiotensin II-Induced Hypertension and Endothelial Dysfunction in Mice

Traditional remedies prepared from Lannea microcarpa leaves, barks, roots, and fruits are used to treat many diseases including hypertension. This study investigated whether oral administration of the ethyl acetate fraction of Lannea microcarpa trunk barks (LMAE) corrects angiotensin (Ang) II-induced hypertension in mice. Its effects on vascular function were specifically investigated. Experiments explored hemodynamic and echocardiographic parameters in vivo and vascular reactivity to acetylcholine (ACh) and CaCl₂ ex vivo on isolated aortas. Mice received LMAE for 3 weeks (50 mg/kg/day) by oral gavage. In the last two weeks of treatment, mice were implanted with osmotic minipumps delivering NaCl (0.9%) or Ang II (0.5 mg/kg/day). LMAE completely prevented the increase in systolic and diastolic blood pressure induced by Ang II. Echocardiographic and kidney parameters were not affected by the different conditions. LMAE abrogated Ang II-induced impairment of ACh-induced relaxation without affecting that of sodium nitroprusside. LMAE also completely prevented CaCl₂-induced contraction in KCl-exposed aorta ex vivo. The extract alone did not modify superoxide (O₂ ^-) and nitric oxide (NO^·) production in femoral arteries from control mice but significantly limited Ang II-induced O₂ ^- production. These effects were associated with reduced expression of inducible isoform of cyclooxygenase- (COX-) 2 and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase isoform NOX-2 in aortas. Finally, phytochemical analysis showed that LMAE contains sterols, triterpenes, coumarins, and anthraquinone. These results showed that LMAE prevents Ang II-induced hypertension and vascular dysfunction through a reduction of oxidative stress linked to COX-2 and NOX-2 pathway and inhibition of calcium entry. This study provides pharmacological basis of the empirical use of Lannea microcarpa trunk bark extract against hypertension.

An Update on the Tissue Renin Angiotensin System and Its Role in Physiology and Pathology

In its classical view, the renin angiotensin system (RAS) was defined as an endocrinesystem involved in blood pressure regulation and body electrolyte balance. However, the emergingconcept of tissue RAS, along with the discovery of new RAS components, increased thephysiological and clinical relevance of the system. Indeed, RAS has been shown to be expressed invarious tissues where alterations in its expression were shown to be involved in multiple diseasesincluding atherosclerosis, cardiac hypertrophy, type 2 diabetes (T2D) and renal fibrosis. In thischapter, we describe the new components of RAS, their tissue-specific expression, and theiralterations under pathological conditions, which will help achieve more tissue- and conditionspecifictreatments.

An Update on the Tissue Renin Angiotensin System and Its Role in Physiology and Pathology

In its classical view, the renin angiotensin system (RAS) was defined as an endocrine system involved in blood pressure regulation and body electrolyte balance. However, the emerging concept of tissue RAS, along with the discovery of new RAS components, increased the physiological and clinical relevance of the system. Indeed, RAS has been shown to be expressed in various tissues where alterations in its expression were shown to be involved in multiple diseases including atherosclerosis, cardiac hypertrophy, type 2 diabetes (T2D) and renal fibrosis. In this chapter, we describe the new components of RAS, their tissue-specific expression, and their alterations under pathological conditions, which will help achieve more tissue- and condition-specific treatments.

Asymmetric Recruitment of β-Arrestin1/2 by the Angiotensin II Type I and Prostaglandin F2α Receptor Dimer

Initially identified as monomers, G protein-coupled receptors (GPCRs) can also form functional homo- and heterodimers that act as distinct signaling hubs for cellular signal integration. We previously found that the angiotensin II (Ang II) type 1 receptor (AT1R) and the prostaglandin F2α (PGF2α) receptor (FP), both important in the control of smooth muscle contractility, form such a functional heterodimeric complex in HEK 293 and vascular smooth muscle cells. Here, we hypothesize that both Ang II- and PGF2α-induced activation of the AT1R/FP dimer, or the parent receptors alone, differentially regulate signaling by distinct patterns of β-arrestin recruitment. Using BRET-based biosensors, we assessed the recruitment kinetics of β-arrestin1/2 to the AT1R/FP dimer, or the parent receptors alone, when stimulated by either Ang II or PGF2α. Using cell lines with CRISPR/Cas9-mediated gene deletion, we also examined the role of G proteins in such recruitment. We observed that Ang II induced a rapid, robust, and sustained recruitment of β-arrestin1/2 to AT1R and, to a lesser extent, the heterodimer, as expected, since AT1R is a strong recruiter of both β-arrestin subtypes. However, PGF2α did not induce such recruitment to FP alone, although it did when the AT1R is present as a heterodimer. β-arrestins were likely recruited to the AT1R partner of the dimer. Gα_q, Gα₁₁, Gα₁₂, and Gα₁₃ were all involved to some extent in PGF2α-induced β-arrestin1/2 recruitment to the dimer as their combined absence abrogated the response, and their separate re-expression was sufficient to partially restore it. Taken together, our data sheds light on a new mechanism whereby PGF2α specifically recruits and signals through β-arrestin but only in the context of the AT1R/FP dimer, suggesting that this may be a new allosteric signaling entity.

Activation of angiotensin type 2 (AT2) receptors prevents myocardial hypertrophy in Zucker diabetic fatty rats

AIMS

Compound 21 (C21), selective AT2 receptor agonist, has cardioprotective effects in experimental models of hypertension and myocardial infarction. The aims of the study was to evaluate the effect of C21, losartan, or both in Zucker diabetic fatty (ZDF) rats (type 2 diabetes) on (1) the prevention of myocardial hypertrophy; (2) myocardial expression of phosphatase and tensin homolog (PTEN), a target gene of miR-30a-3p, involved in myocardial remodelling.

METHODS

Experiments were performed in ZDF (n = 33) and in control Lean (8) rats. From the 6th to the 20th week of age, we administered C21 (0.3 mg/kg/day) to 8 ZDF rats. 8 ZDF rats were treated with losartan (10 mg/kg/day), 8 rats underwent combination treatment, C21+ losartan, and 9 ZDF rats were left untreated. Blood glucose and blood pressure were measured every 4 weeks. At the end of the study the hearts were removed, the apex was cut for the quantification of PTEN mRNA and miR-30a-3p expression (realtime-PCR). Myocardial hypertrophy was evaluated by histomorphometric analysis, and nitrotyrosine expression (as marker of oxidative stress) by immunohistochemistry.

RESULTS

ZDF rats had higher blood glucose (p < 0.0001) with respect to control Lean rats, while blood pressure did not change. Both parameters were not modified by C21 treatment, while losartan and losartan + C21 reduced blood pressure in ZDF rats (p < 0.05). miR-30a-3p expression was increased in ZDF rats (p < 0.01) and PTEN mRNA expression was decreased (p < 0.05). ZDF rats developed myocardial hypertrophy (p < 0.01) and increased oxidative stress (p < 0.01), both were prevented by C21 or losartan, or combination treatment. C21 or losartan normalized the expression of miR-30a-3p and PTEN.

CONCLUSIONS

Activation of AT2 receptors or AT1 receptor blockade prevents the development of myocardial hypertrophy in ZDF rats. This occurs through the modulation of the miR-30a-3p/PTEN interaction.

Alterations in vascular function by syncytiotrophoblast extracellular vesicles via lectin-like oxidized low-density lipoprotein receptor-1 in mouse uterine arteries

Syncytiotrophoblast extracellular vesicles (STBEVs), released into the maternal circulation during pregnancy, have been shown to affect vascular function; however, the mechanism remains unknown. In rats, STBEVs were shown to reduce endothelium-mediated vasodilation via lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a multi-ligand scavenger receptor that has been associated with vascular dysfunction. Recently, LOX-1 was shown to interact with the angiotensin II type 1 receptor (AT-1). We hypothesized that, in pregnant mice, STBEVs would impair vascular function via LOX-1 and would specifically affect angiotensin II responses. Uterine arteries from pregnant control (C57BL/6) and LOX-1 knockout (LOX-1KO) mice were isolated on gestational day (GD) 18.5. Endothelium-dependent (methylcholine (MCh); ± N(G)-Nitro-L-arginine methyl ester to assess nitric oxide (NO) contribution), and -independent (sodium nitroprusside) vasodilation, and vasoconstriction (angiotensin II; ± AT-1 [candesartan] or angiotensin II type 2 receptor (AT-2) [PD123.319] receptor antagonists; high potassium salt solution) responses were assessed using wire myography. AT-1 and AT-2 expression was analyzed using fluorescence microscopy. Human umbilical vein endothelial cells (HUVECs) were stimulated with STBEVs ± LOX-1 blocking antibody, and superoxide and peroxynitrite production were analyzed. Although MCh-induced vasodilation was decreased (P=0.0012), NO contribution to vasodilation was greater in LOX-1KO mice (P=0.0055). STBEVs delayed angiotensin II tachyphylaxis in arteries from control but not LOX-1KO mice (P<0.0001), while AT-1 and AT-2 expression was unchanged. STBEVs increased peroxynitrite production in HUVECs via LOX-1 (P=0.0091). In summary, LOX-1 deletion altered endothelium-mediated vasodilation, suggesting that LOX-1 contributes to vascular adaptations in pregnancy. STBEVs increased angiotensin II responsiveness and oxidative stress levels via LOX-1, suggesting that increased LOX-1 expression/activation or STBEVs could adversely affect vascular function and contribute to vascular complications of pregnancy.

Inhibition of renin-angiotensin axis reduces the risk of thrombus formation in the left atrial appendage in patients with hypertension complicated by atrial fibrillation

Aims:

We examined whether the use of a renin-angiotensin-aldosterone system (RAS) inhibitor plays a role in protecting against left atrial appendage thrombus (LAAT) in patients with hypertension complicated by atrial fibrillation (AF).

Methods:

Two observational studies were conducted on patients with diagnoses of hypertension and AF, who were categorized into RAS inhibitor user or nonuser groups. Demographic characteristics, clinical characteristics, echocardiographic parameters and hemostatic markers were examined and the occurrence of LAAT during follow-up were recorded.

Results:

In the first study (n = 131), LA peak systolic strain and LAA emptying flow velocity (LAA eV) were significantly increased in patients on RAS inhibitors compared with the nonuser group (p < 0.05). Lower D-dimer and fibrinogen levels were observed in patients on RAS inhibitors (p < 0.05). In the second study (n = 99), 25.9% (n = 11) of patients on RAS inhibitors developed LAAT, compared with 46.7% (n = 21) in the nonuser group (p < 0.05). After controlling for risk factors related to LAAT, use of RAS inhibitors remained associated with a significantly lower risk of developing LAAT (HR, 0.406; 95% CI, 0.191–0.862; p = 0.019).

Conclusions:

RAS inhibitors use was associated with a significant reduction in the risk of LAAT in patients with hypertension and AF.

Cell-Specific Protective Signaling Induced by the Novel AT2R-Agonist NP-6A4 on Human Endothelial and Smooth Muscle Cells

Cardiovascular disease incidence continues to rise and new treatment paradigms are warranted. We reported previously that activation of Angiotensin II receptor (encoded by the X-linked Agtr2 gene) by a new peptide agonist, NP-6A4, was more effective in protecting mouse cardiomyocyte HL-1 cells and human coronary artery vascular smooth muscle cells (hCAVSMCs) from acute nutrient deficiency than other drugs tested. To elucidate further the protective effects of NP-6A4 in human cells, we studied the effects of NP-6A4 treatment on functions of human coronary artery endothelial cells (hCAECs), and hCAVSMCs. In hCAVSMCs, NP-6A4 (1 μM) increased Agtr2 mRNA (sixfold, p < 0.05) after 12-h exposure, whereas in hCAECs, significant increase in Agtr2 mRNA (hCAECs: eightfold) was observed after prolonged exposure. Interestingly, NP-6A4 treatment (1 μM, 12 h) increased AT2R protein levels in all human cells tested. Pre-treatment with AT2R-antagonist PD123319 (20 μM) and anti-AT2R siRNA (1 μM) suppressed this effect. Thus, NP-6A4 activates a positive feedback loop for AT2R expression and signaling in hCAVSMCs and hCAECs. NP-6A4 (1–20 μM) increased cell index (CI) of hCAVSMCs as determined by real time cell analyzer (RTCA), indicating that high concentrations of NP-6A4 were not cytotoxic for hCAVSMCs, rather promoting better cell attachment and growth. Seahorse Extracellular Flux Assay revealed that NP-6A4 (1 μM) treatment for 7 days increased whole cell-based mitochondrial parameters of hCAVSMCs, specifically maximal respiration (p < 0.05), spare respiratory capacity (p < 0.05) and ATP production (p < 0.05). NP-6A4 (1 μM; 7 days) also suppressed Reactive Oxygen Species (ROS) in hCAVSMCs. Exposure to Doxorubicin (DOXO) (1 μM) increased ROS in hCAVSMCs and this effect was suppressed by NP-6A4 (1 μM). In hCAECs grown in complete medium, NP-6A4 (1 μM) and Ang II (1 μM) exerted similar changes in CI. Additionally, NP-6A4 (5 μM: 12 h) increased expression of eNOS (sixfold, p < 0.05) and generation of nitric oxide (1.3-fold, p < 0.05) in hCAECs and pre-treatment with PD123319 (20 μM) suppressed this effect partially (65%). Finally, NP-6A4 decreased phosphorylation of Jun-N-terminal kinase, implicated in apoptosis of ECs in atherosclerotic sites. Taken together, NP-6A4, through its ability to increase AT2R expression and signaling, exerts different cell-specific protective effects in human VSMCs and ECs.

Fifteen years of LIFE (Losartan Intervention for Endpoint Reduction in Hypertension)-Lessons learned for losartan: An "old dog playing good tricks"

There is an unmet need to prevent cardiovascular disease and chronic kidney disease development and progression worldwide. Losartan, the first angiotensin receptor blocker, was shown to exert significant cardioprotective and renoprotective effects in the LIFE (Losartan Intervention for Endpoint Reduction in Hypertension) and RENAAL (Reduction of Endpoints in NIDDM With the Angiotensin II Antagonist Losartan) trials. Losartan significantly prevented stroke and decreased serum uric acid levels and the rates of new-onset diabetes mellitus and atrial fibrillation. The present review discusses the LIFE (and its subanalyses) and RENAAL trials and the translation of their results to clinical practice. The place of losartan in the current guidelines for hypertension management is also discussed. Losartan still represents an efficacious, safe, and cost-effective therapeutic option in patients with hypertension who have left ventricular hypertrophy. Losartan is a useful antihypertensive agent for stroke prevention and in the management of patients with chronic kidney disease, atrial fibrillation, diabetes mellitus, albuminuria, and hyperuricemia.

Naringenin inhibits NG-nitro-L-arginine methyl ester-induced hypertensive left ventricular hypertrophy by decreasing angiotensin-converting enzyme 1 expression

Naringenin (NGN) is a natural flavonoid that exerts antiinflammatory, antioxidant and cardioprotective effects. The present study investigated the effects of NGN on left ventricular hypertrophy in rats with N^G-nitro-L-arginine methyl ester (L-NAME)-induced hypertension, and sought to determine the underlying mechanism of action. The rats received the following by gavage daily for 56 days: L-NAME (50 mg/kg/day) + NGN (100 mg/kg/day), L-NAME (50 mg/kg/day) + saline, or saline + saline. Blood pressure, heart rate and body weight were recorded. Left ventricular hypertrophy was assessed by echocardiography and hematoxylin-eosin staining. Angiotensin II (Ang II) and angiotensin-converting enzyme 1 (ACE1), which serve a pivotal role in cardiac remodeling, were evaluated by ELISA, reverse transcription-quantitative polymerase chain reaction and western blot analysis. NGN had no significant effect on body weight, heart rate or blood pressure. The extent of left ventricular hypertrophy in the L-NAME + NGN group was lower than in the L-NAME + saline group on day 56. NGN decreased Ang II and ACE1 protein levels in myocardial tissues. In conclusion, Ang II and ACE1 expression in cardiac tissue was inhibited by NGN in L-NAME-treated rats, which may contribute to the inhibitory effects of NGN on left ventricular hypertrophy that is induced by pressure overload.

The Dynamics of GPCR Oligomerization and Their Functional Consequences

The functional importance of G protein-coupled receptor (GPCR) oligomerization remains controversial. Although obligate dimers of class C GPCRs are well accepted, the generalizability of this phenomenon is still strongly debated with respect to other classes of GPCRs. In this review, we focus on understanding the organization and dynamics between receptor equivalents and their signaling partners in oligomeric receptor complexes, with a view toward integrating disparate viewpoints into a unified understanding. We discuss the nature of functional oligomeric entities, and how asymmetries in receptor structure and function created by oligomers might have implications for receptor function as allosteric machines and for future drug discovery.

Cough and ACE Inhibitors: The Truth Beyond Placebo

Angiotensin converting enzyme (ACE) inhibitors are extensively used for the prevention and treatment of cardiovascular diseases with a wide range of clinical recommendations. The use of ACE inhibitors can cause the onset of a dry cough, whose prevalence has probably been overestimated because of the lack of adequate control. A correct interpretation of available data requires a careful evaluation of placebo-controlled studies to definitely assess the rate of the most frequent adverse event of ACE inhibition.

Biotechnological production of the angiotensin-converting enzyme inhibitory dipeptide isoleucine-tryptophan

Peptides with angiotensin-converting enzyme (ACE)-inhibitory and antihypertensive effects are suggested as innovative food additives to prevent or treat hypertension. Currently, these substances are isolated from food proteins following nonselective hydrolysis as a mixture of ACE-inhibitory peptides and other protein fragments. This study presents an innovative biotechnological method, based on recombinant DNA technology that was established to specifically produce the ACE-inhibitory dipeptide isoleucine-tryptophan. In a first step, a repetitive isoleucine-tryptophan construct fused to the maltose-binding protein was generated and expressed in Escherichia coli BL21 cells. The chromatographically purified recombinant fusion protein was enzymatically hydrolyzed using α-chymotrypsin to liberate the dipeptide isoleucine-tryptophan. The identity of the liberated isoleucine-tryptophan was confirmed by MS and derivatization of its N-terminus. The ACE-inhibitory effect of the recombinant dipeptide on soluble and membrane bound ACE was found to be indistinguishable from the inhibitory potential of the chemically produced commercially available dipeptide. The established experimental strategy represents a promising approach to the biotechnical production of sufficient amounts of recombinant peptide-based ACE-inhibitory and antihypertensive substances that are applicable as functional food additives to delay or even prevent hypertension.

Effects of natural peptides from food proteins on angiotensin converting enzyme activity and hypertension

Cardiovascular diseases are the leading cause of death. The underlying pathophysiology is largely contributed by an overactivation of the renin-angiotensin-aldosterone-system (RAAS). Herein, angiotensin II (AngII) is a key mediator not only in blood pressure control and vascular tone regulation, but also involved in inflammation, endothelial dysfunction, atherosclerosis, hypertension and congestive heart failure. Since more than three decades suppression of AngII generation by inhibition of the angiotensin-converting enzyme (ACE) or blockade of the AngII-receptor has shown clinical benefit by reducing hypertension, atherosclerosis and other inflammation-associated cardiovascular diseases. Besides pharmaceutical ACE-inhibitors some natural peptides derived from food proteins reduce in vitro ACE activity. Several animal studies and a few human clinical trials have shown antihypertensive effects of such peptides, which might be attractive as food additives to prevent age-related RAAS activation. However, their inhibitory potency on in vitro ACE activity does not always correlate with an antihypertensive impact. While some peptides with high inhibitory activity on ACE-activity in vitro show no antihypertensive effect in vivo, other peptides with only a moderate ACE inhibitory activity in vitro cause such effects. The explanation for this conflicting phenomenon between inhibitory activity and antihypertensive effect remains unclear to date. This review shall critically address the effects of natural peptides derived from different food proteins on the cardiovascular system and the possible underlying mechanisms. A central aspect will be to point to conceptual gaps in the current understanding of the action of these peptides with respect to in vivo blood pressure lowering effects.

The benefit of angiotensin AT1 receptor blockers for early treatment of hypertensive patients

ESC guidelines for management of arterial hypertension allow one to choose among five classes of antihypertensive drugs indiscriminately. They are based on the principle that in the management of hypertensive patients, it is fundamental to reduce blood pressure (BP), independently of the utilized drug. However, it has been demonstrated that the renin-angiotensin system (RAS) plays a relevant role in the hypertensive-derived development and progression of organ damage. Thus, antihypertensive drugs interfering with the RAS should be preferred in preventing and reducing target organ damage. The availability of two classes of drugs, ACE-inhibitors and angiotensin AT1 receptor blockers (ARBs), both interfering with the RAS, makes the choice between them difficult. Both pharmacological strategies offer an effective BP control, and a substantial improvement of prognosis in different associated pathologies. Regarding cardiovascular prevention, ACE-inhibitors have an extensive scientific literature regarding utility in high-risk patients. Nevertheless, there is evidence to support the concept that in the early phases of organ tissue damage, the RAS is activated, but the ACE pathway producing angiotensin II is not always employed. Accordingly, ACE-inhibitors appear to be less effective, whereas ARBs have a greater beneficial action in the initial stages of atherosclerotic disease. Moreover, patients undergoing ARBs therapy show a substantially lower risk of therapy discontinuation when compared to those treated with ACE-inhibitors, because of a better tolerability. In conclusion, ACE-inhibitors should be used in patients who have already developed organ damage, but tolerate this drug well, while ARBs should be the first choice in naïve hypertensive patients without organ damage or at the initial stages of disease.

LCZ696, a promising novel agent in treating hypertension (a meta-analysis of randomized controlled trials)

Background

To determine the effectiveness and safety of LCZ696 for the clinical treatment of hypertension, we performed a meta-analysis of the previous clinical trials.

Methods

Relevant English articles and randomized controlled trials were searched in Pubmed, Embase, EBSCO, Cochrane base and ClinicalTrials.gov. The last search date was July 20th, 2017.

Results

Compared with 20mg olmesartan, 200mg and 400mg LCZ696 outperformed olmesartan in terms of reducing mean sitting systolic blood pressure, mean ambulatory systolic blood pressure, mean sitting diastolic blood pressure and mean ambulatory diastolic blood pressure. Compared with 20mg olmesartan, 200mg and 400mg LCZ696 was better than olmesartan in terms of reducing mean sitting pulse pressure. And these studies showed that 400mg LCZ696 was better than 20mg olmesartan in terms of reducing mean ambulatory pulse pressure, however, there was no significant difference between 200mg LCZ696 and 20mg olmesartan in terms of redducing mean ambulatory pulse pressure. In addition, 200mg and 400mg LCZ696 was better than placebo in terms of reducing blood pressure parameters mentioned above. Compared with placebo or 20 mg olmesartan, LCZ696 showed no superiority in terms of reducing adverse events or serious adverse events.

Conclusions

LCZ696 at 200 mg or 400 mg was better at reducing most of blood pressure parameters than 20 mg olmesartan or placebo. Compared with placebo or 20 mg olmesartan, 200 mg or 400 mg LCZ696 do not result in more adverse events in treating hypertension.

Personalised Single-Pill Combination Therapy in Hypertensive Patients: An Update of a Practical Treatment Platform

Despite the improvements in the management of hypertension during the last three decades, it continues to be one of the leading causes of cardiovascular morbidity and mortality worldwide. Effective and sustained reductions in blood pressure (BP) reduce the incidence of myocardial infarction, stroke, congestive heart failure and cardiovascular death. However, the proportion of patients who achieve the recommended BP goal (< 140/90 mmHg) is persistently low, worldwide. Poor adherence to therapy, complex therapeutic regimens, clinical inertia, drug-related adverse events and multiple risk factors or comorbidities contribute to the disparity between the potential and actual BP control rate. Previously we published a practical therapeutic platform for the treatment of hypertension based on clinical evidence, guidelines, best practice and clinical experience. This platform provides a personalised treatment approach and can be used to improve BP control and simplify treatment. It uses long-acting, effective and well-tolerated angiotensin receptor blocker (ARB) olmesartan, in combination with a calcium channel blocker amlodipine, and/or a thiazide diuretic hydrochlorothiazide. These drugs were selected based on the availability in most European Countries of single-pill, fixed formulations in a wide range of doses for both dual- and triple-drug combinations. The platform approach could be applied to other ARBs or angiotensin-converting enzyme inhibitors available in single-pill, fixed-dose combinations. Here, we present an update, which takes into account the results of the recently published studies and extends the applicability of the platform to common conditions that are often neglected or poorly considered in clinical practice guidelines.