Counter-regulatory renin-angiotensin system in cardiovascular disease

ANGIOTENSIN II FOR CATECHOLAMINE-RESISTANT VASODILATORY SHOCK IN PATIENTS WITH ACUTE KIDNEY INJURY: A POST HOC ANALYSIS OF THE ATHOS-3 TRIAL

ABSTRACT

Objective: The combination of catecholamine-resistant vasodilatory shock and acute kidney injury (AKI) is associated with high morbidity and mortality. The role of angiotensin II (ANGII) in this setting is unclear. Methods: We conducted a post hoc analysis of the Angiotensin II for the Treatment of High-Output Shock (ATHOS) 3 trial which assessed the effect of Intravenous ANG II or placebo in patients with refractory vasodilatory shock in 75 intensive care units across nine countries in North America, Australasia, and Europe. We included patients with all stages AKI at initiation of ANG II or placebo and assessed 28-day mortality as primary outcome. We studied mean arterial pressure (MAP) response and days alive and free from renal replacement therapy (RRT) up to day 7 as secondary outcome. Results: Of 321 ATHOS-3 patients, 203 (63%) had AKI at randomization, with stage 3 AKI being dominant (67%). Median age was 63 years and median APACHE II score was 30. By day 28, overall, 118 (58%) of patients had died (53% with ANGII vs. 63% with placebo, hazard ratio = 0.75, 95% CI [0.52-1.08], P = 0.121). Among AKI stage 3 patients, however, ANGII was associated with significantly lower mortality (48% vs. 67%, hazard ratio = 0.57, 95% CI [0.36-0.91], P = 0.024). Additionally, in this subgroup, compared with placebo, patients receiving ANGII were more likely to achieve a MAP response (P < 0.001) and had more days alive and free from RRT (P < 0.001). Conclusions: Compared with placebo, in patients with catecholamine-resistant vasodilatory shock and stage 3 AKI, ANGII is associated with lower 28-day, greater likelihood of MAP response, and more days alive and free from RRT. These findings support the conduct of future ANGII trials in patients with stage 3 AKI.

The Complex Connection Between Myocardial Dysfunction and Cancer Beyond Cardiotoxicity: Shared Risk Factors and Common Molecular Pathways

Cardiovascular diseases and cancer represent the largest disease burden worldwide. Previously, these two conditions were considered independent, except in terms of cardiotoxicity, which links cancer treatment to subsequent cardiovascular issues. However, recent studies suggest that there are further connections between cancer and heart disease beyond cardiotoxicity. It has been revealed that myocardial dysfunction may promote carcinogenesis, indicating that additional common pathophysiological mechanisms might be involved in the relationship between cardiology and oncology, rather than simply a connection through cardiotoxic effects. These mechanisms may include shared risk factors and common molecular pathways, such as persistent inflammation and neurohormonal activation. This review explores the connection between myocardial dysfunction and cancer, emphasizing their shared risk factors, similar biological mechanisms, and causative factors like cardiotoxicity, along with their clinical implications.

Therapeutic opportunities in targeting the protective arm of the renin-angiotensin system to improve insulin sensitivity: a mechanistic review

In recent years, the knowledge of the physiological and pathophysiological roles of the renin-angiotensin system (RAS) in glucose metabolism has advanced significantly. It is now well-established that blockade of the angiotensin AT1 receptor (AT1R) improves insulin sensitivity. Activation of the AT2 receptor (AT2R) and the MAS receptor are significant contributors to this beneficial effect. Elevated availability of angiotensin (Ang) II) for interaction with the AT2R and increased Ang-(1-7) formation during AT1R blockade mediate these effects. The ongoing development of selective AT2R agonists, such as compound 21 and the novel Ang III peptidomimetics, has significantly advanced the exploration of the role of AT2R in metabolism and its potential as a therapeutic target. These agents show promise, particularly when RAS inhibition is contraindicated. Additionally, other RAS peptides, including Ang IV, des-Asp-Ang I, Ang-(1-9), and alamandine, hold therapeutic capability for addressing metabolic disturbances linked to type 2 diabetes. The possibility of AT2R heteromerization with either AT1R or MAS receptor offers an exciting area for future research, particularly concerning therapeutic strategies to improve glycemic control. This review focuses on therapeutic opportunities to improve insulin sensitivity, taking advantage of the protective arm of the RAS.

Implications of β-Arrestin biased signaling by angiotensin II type 1 receptor for cardiovascular drug discovery and therapeutics

Angiotensin II receptors, Type 1 (AT1R) and Type 2 (AT2R) are 7TM receptors that play critical roles in both the physiological and pathophysiological regulation of the cardiovascular system. While AT1R blockers (ARBs) have proven beneficial in managing cardiac, vascular and renal maladies they cannot completely halt and reverse the progression of pathologies. Numerous experimental and animal studies have demonstrated that β-arrestin biased AT1R-ligands (such as SII-AngII, S1I8, TRV023, and TRV027) offer cardiovascular benefits by blocking the G protein signaling while retaining the β-arrestin signaling. However, these ligands failed to show improvement in heart-failure outcome over the placebo in a phase IIb clinical trial. One major limitation of current β-arrestin biased AT1R-ligands is that they are peptides with short half-lives, limiting their long-term efficacy in patients. Additionally, β-arrestin biased AT1R-ligand peptides, may inadvertently block AT2R, a promiscuous receptor, potentially negating its beneficial effects in post-myocardial infarction (MI) patients. Therefore, developing a small molecule β-arrestin biased AT1R-ligand with a longer half-life and specificity to AT1R could be more effective in treating heart failure. This approach has the potential to revolutionize the treatment of cardiovascular diseases by offering more sustained and targeted therapeutic effects.

Principle role of the (pro)renin receptor system in cardiovascular and metabolic diseases: An update

(Pro)renin receptor (PRR), along with its soluble form, sPRR, functions not only as a crucial activator of the local renin-angiotensin system but also engages with and activates various angiotensin II-independent signaling pathways, thus playing complex and significant roles in numerous physiological and pathophysiological processes, including cardiovascular and metabolic disorders. This article reviews current knowledge on the intracellular partners of the PRR system and explores its physiological and pathophysiological impacts on cardiovascular diseases as well as conditions related to glucose and lipid metabolism, such as hypertension, heart disease, liver disease, diabetes, and diabetic complications. Targeting the PRR system could emerge as a promising therapeutic strategy for treating these conditions. Elevated levels of circulating sPRR might indicate the severity of these diseases, potentially serving as a biomarker for diagnosis and prognosis in clinical settings. A comprehensive understanding of the functions and regulatory mechanisms of the PRR system could facilitate the development of novel therapeutic approaches for the prevention and management of cardiovascular and metabolic diseases.

A real-world pharmacovigilance analysis of adverse events associated with irbesartan using the FAERS and JADER databases

Objective

Hypertension is a leading global risk factor for disability and death. Irbesartan, a potent angiotensin II receptor blocker, requires continuous safety monitoring. We conducted a disproportionality analysis of irbesartan-related adverse drug events (ADEs) using the FDA's FAERS and Japan's JADER databases.

Methods

We extracted irbesartan-related ADE reports from FAERS (Q1 2004 to Q1 2024) and JADER (Q2 2008 to Q4 2023). We used Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Empirical Bayesian Geometric Mean (EBGM) for signal detection. Sensitivity analyses were conducted to exclude comorbid medications, and subgroup analyses by age and gender were performed to explore ADE occurrence in specific populations. Th time to onset (TTO) of ADEs was assessed using Weibull distribution test and Kaplan-Meier curves.

Results

A total of 5,816 (FAERS) and 366 (JADER) reports were analyzed, with irbesartan-related preferred terms (PTs) involving 27 System Organ Classes (SOCs) in FAERS and 22 in JADER. Three SOCs met detection thresholds in both databases: "metabolism and nutrition disorders," "cardiac disorders," and "renal and urinary disorders." We identified 219 positive signals in FAERS and 20 in JADER, including known signals like hyperkalemia, hypotension, and acute kidney injury. Notably, newly identified signals such as acute pancreatitis (n = 50, ROR: 7.76 [5.88-10.25]) and rhabdomyolysis (n = 50, ROR: 7.76 [5.88-10.25]) in FAERS and respiratory failure (n = 7, ROR: 6.76 [3.20-14.26]) in JADER could have significant clinical implications, as they may lead to severe outcomes if not recognized and managed promptly. Subgroup analyses revealed both similarities and differences in signal detection across gender and age groups. Sensitivity analyses, excluding concomitant medications, confirmed the persistence of key positive signals, including hyperkalemia, angioedema, acute pancreatitis, and agranulocytosis. ADEs mainly occurred within 1 month (34.14%) and after 1 year (32.32%) after dosing, with a median onset of 107 days.

Conclusion

This study provides valuable real-world evidence on the safety profile of irbesartan. The identification of new safety signals underscores the necessity of updating drug labels, particularly for assessing and managing high-risk patients. Additionally, the TTO analysis emphasizes the importance of sustained vigilance for adverse events over time. In conclusion, our findings contribute to a more comprehensive understanding of irbesartan's safety, aiding healthcare professionals in optimizing its use in clinical practice.

Nanopore approaches for single-molecule temporal omics: promises and challenges

The great molecular heterogeneity within single cells demands omics analysis from a single-molecule perspective. Moreover, considering the perpetual metabolism and communication within cells, it is essential to determine the time-series changes of the molecular library, rather than obtaining data at only one time point. Thus, there is an urgent need to develop a single-molecule strategy for this omics analysis to elucidate the biosystem heterogeneity and temporal dynamics. In this Perspective, we explore the potential application of nanopores for single-molecule temporal omics to characterize individual molecules beyond mass, in both a single-molecule and high-throughput manner. Accordingly, recent advances in nanopores available for single-molecule temporal omics are reviewed from the view of single-molecule mass identification, revealing single-molecule heterogeneity and illustrating temporal evolution. Furthermore, we discuss the primary challenges associated with using nanopores for single-molecule temporal omics in complex biological samples, and present the potential strategies and notes to respond to these challenges.

AI4ACEIP: A Computing Tool to Identify Food Peptides with High Inhibitory Activity for ACE by Merged Molecular Representation and Rich Intrinsic Sequence Information Based on an Ensemble Learning Strategy

Hypertension is a common chronic disorder and a major risk factor for cardiovascular diseases. Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II, causing vasoconstriction and raising blood pressure. Pharmacotherapy is the mainstay of traditional hypertension treatment, leading to various negative side effects. Some food-derived peptides can suppress ACE, named ACEIP with fewer undesirable effects. Therefore, it is crucial to seek strong dietary ACEIP to aid in hypertension treatment. In this article, we propose a new model called AI4ACEIP to identify ACEIP. AI4ACEIP uses a novel two-layer stacked ensemble architecture to predict ACEIP relying on integrated view features derived from sequence, large language models, and molecular-based information. The analysis of feature combinations reveals that four selected integrated feature pairs exhibit enhancing performance for identifying ACEIP. For finding meta models with strong abilities to learn information from integrated feature pairs, PowerShap, a feature selection method, is used to select 40 optimal feature and meta model combinations. Compared with seven state-of-the-art methods on the source and clear benchmark data sets, AI4ACEIP significantly outperformed by 8.47 to 20.65% and 5.49 to 14.42% for Matthew's correlation coefficient. In brief, AI4ACEIP is a reliable model for ACEIP prediction and is freely available at https://github.com/abcair/AI4ACEIP.

Unraveling the protective genetic architecture of COVID-19 in the Brazilian Amazon

Despite all the efforts acquired in four years of the COVID-19 pandemic, the path to a full understanding of the biological mechanisms involved in this disease remains complex. This is partly due to a combination of factors, including the inherent characteristics of the infection, socio-environmental elements, and the variations observed within both the viral and the human genomes. Thus, this study aimed to investigate the correlation between genetic host factors and the severity of COVID-19. We conducted whole exome sequencing (WES) of 124 patients, categorized into severe and non-severe groups. From the whole exome sequencing (WES) association analysis, four variants (rs1770731 in CRYBG1, rs7221209 in DNAH17, rs3826295 in DGKE, and rs7913626 in CFAP46) were identified as potentially linked to a protective effect against the clinical severity of COVID-19, which may explain the less severe impact of COVID-19 on the Northern Region. Our findings underscore the importance of carrying out more genomic studies in populations living in the Amazon, one of the most diverse from the point of view of the presence of rare and specific alleles. To our knowledge, this is the first WES study of admixed individuals from the Brazilian Amazon to investigate genomic variants associated with the clinical severity of COVID-19.

Nanomedicine: A great boon for cardiac regenerative medicine

Cardiovascular disease (CVD) represents a significant global health challenge, remaining the leading cause of illness and mortality worldwide. The adult heart's limited regenerative capacity poses a major obstacle in repairing extensive damage caused by conditions like myocardial infarction. In response to these challenges, nanomedicine has emerged as a promising field aimed at improving treatment outcomes through innovative drug delivery strategies. Nanocarriers, such as nanoparticles (NPs), offer a revolutionary approach by facilitating targeted delivery of therapeutic agents directly to the heart. This precise delivery system holds immense potential for treating various cardiac conditions by addressing underlying mechanisms such as inflammation, oxidative stress, cell death, extracellular matrix remodeling, prosurvival signaling, and angiogenic pathways associated with ischemia-reperfusion injury. In this review, we provide a concise summary of the fundamental mechanisms involved in cardiac remodeling and regeneration. We explore how nanoparticle-based drug delivery systems can effectively target the afore-mentioned mechanisms. Furthermore, we discuss clinical trials that have utilized nanoparticle-based drug delivery systems specifically designed for cardiac applications. These trials demonstrate the potential of nanomedicine in clinical settings, paving the way for future advancements in cardiac therapeutics through precise and efficient drug delivery. Overall, nanomedicine holds promise in revolutionizing the treatment landscape of cardiovascular diseases by offering targeted and effective therapeutic strategies that address the complex pathophysiology of cardiac injuries.

Neuronal ACE1 knockout disrupts the hippocampal renin angiotensin system leading to memory impairment and vascular loss in normal aging

Angiotensin I converting enzyme (ACE1) maintains blood pressure homeostasis by converting angiotensin I into angiotensin II in the renin-angiotensin system (RAS). ACE1 is expressed in the brain, where an intrinsic RAS regulates complex cognitive functions including learning and memory. ACE1 has been implicated in neurodegenerative disorders including Alzheimer's disease and Parkinson's disease, but the mechanisms remain incompletely understood. Here, we performed single-nucleus RNA sequencing to characterize the expression of RAS genes in the hippocampus and discovered that Ace is mostly expressed in CA1 region excitatory neurons. To gain a deeper understanding of the function of neuronal ACE1, we generated ACE1 conditional knockout (cKO) mice lacking ACE1 expression specifically in hippocampal and cortical excitatory neurons. ACE1 cKO mice exhibited hippocampus-dependent memory impairment in the Morris water maze, y-maze, and fear conditioning tests. Total ACE1 level was significantly reduced in the cortex and hippocampus of ACE1 cKO mice showing that excitatory neurons are the predominant cell type expressing ACE1 in the forebrain. Despite similar reductions in total ACE1 level in both the hippocampus and cortex, the RAS pathway was dysregulated in the hippocampus only. Importantly, ACE1 cKO mice exhibited age-related capillary loss selectively in the hippocampus. Here, we show selective vulnerability of the hippocampal microvasculature and RAS pathway to neuronal ACE1 knockout. Our results provide important insights into the function of ACE1 in the brain and demonstrate a connection between neuronal ACE1 and cerebrovascular function in the hippocampus.

Expression levels of ACE and ACE2 in the placenta and white adipose tissue of lean and obese pregnant women

BACKGROUND

This study evaluated the expression of ACE and ACE2 in the placenta and white adipose tissue in lean and obese women, and correlated their levels with anthropometric, clinical, and laboratory parameters, and tissue count of inflammatory cells.

METHODS

A cross-sectional analytical study was performed with 49 pregnant women and their respective newborns. Samples of placenta and adipose tissue were used for measuring mRNA expression for ACE and ACE2 through qRT-PCR. Inflammatory cell counting was performed through conventional microscopy.

RESULTS

An increase in ACE expression and a decrease in ACE2 were observed in the placenta and adipose tissue of women with obesity. ACE2 levels showed a negative correlation with pre-pregnancy BMI and total cholesterol.

CONCLUSION

Maternal obesity can modulate the expression of RAS components in the placenta and white adipose tissue, with ACE2 correlated with pre-pregnancy BMI and total cholesterol.

ER stress improvement by aerobic training or enalapril differently ameliorates pathological cardiac remodeling in obese mice

Overactivation of the classic arm of the renin-angiotensin system (RAS) is one of the main mechanisms involved in obesity-related cardiac remodeling, and a possible relationship between RAS and ER stress in the cardiovascular system have been described. Thus, the aim of this study is to evaluate if activating the protective arm of the RAS by ACE inhibition or aerobic exercise training could overturn diet-induced pathological cardiac hypertrophy by attenuating ER stress. Male C57BL/6 mice were fed a control (SC) or a high-fat diet (HF) for 16 weeks. In the 8th week, HF-fed animals were randomly divided into HF, enalapril treatment (HF-En), and aerobic exercise training (HF-Ex) groups. Body mass (BM), food and energy intake, plasma analyzes, systolic blood pressure (SBP), physical conditioning, and plasma ACE and ACE2 activity were evaluated. Cardiac morphology, and protein expression of hypertrophy, cardiac metabolism, RAS, and ER stress markers were assessed. Data presented as mean ± standard deviation and analyzed by one-way ANOVA with Holm-Sidak post-hoc. HF group had increased BM and SBP, and developed pathological concentric cardiac hypertrophy, with overactivation of the classic arm of the RAS, and higher ER stress. Both interventions reverted the increase in BM, and SBP, and favored the protective arm of the RAS. Enalapril treatment improved pathological cardiac hypertrophy with partial reversal of the concentric pattern, and slightly attenuated cardiac ER stress. In contrast, aerobic exercise training induced physiological eccentric cardiac hypertrophy, and fully diminished ER stress.

Transplantation of human umbilical cord-derived mesenchymal stem cells improves age-related ovarian functional decline via regulating the local renin-angiotensin system on inflammation and oxidative stress

BACKGROUND

Age-related reproductive aging is a natural and irreversible physiological process, and delaying childbearing is increasingly common all over the world. Transplantation of mesenchymal stem cells (MSCs) is considered a new and effective therapy to restore ovarian function, but the relevant mechanisms remain unclear. Recently, it has been found that there is a local Renin-angiotensin system (RAS) in human ovary and it plays a key role.

METHODS

After collecting follicular fluid from women who received oocyte retrieval for pure male factor infertility, the level of RAS components in it were detected, and the correlation analysis by linear regression. Then, the in vivo experiments on female C57BL/6 mice were designed to measure ovarian function, and the transcription and translation levels of RAS pathway were detected by molecular biology methods. Moreover, the role of RAS in regulating inflammation and oxidative stress in the co-culture system were explored in in vitro experiments on KGN cells.

RESULTS

First, a total of 139 samples of analyzable follicular fluid were obtained. The local RAS of ovary, which is independent of systemic RAS (P > 0.05), is affected by age (Pearson r < 0, P < 0.05) and related to ovarian function, inflammation, oxidative stress indexes and assisted reproduction laboratory outcomes (P < 0.05). Next, the ovary/body weight of aging mice decreased significantly and serum sex hormones levels changed significantly (P < 0.01). The number of functional follicles decreased, while the atresia follicles increased (P < 0.05). After MSCs transplantation, all the above measures have been partially recovered (P < 0.05). Although several RAS components in aging ovary changed, MSCs only improved the expression level of AT1R (P < 0.05). Furthermore, the secretion ability and mitochondrial membrane potential of aging KGN cells decreased, while the intracellular ROS level and the aging cells ratio increased (P < 0.01). All the above measures have been partially recovered when co-cultured with MSCs (P < 0.05). After Ang(1-7) were added into the co-culture system, the above have been more significantly restored compared with Ang II (P < 0.05). Nevertheless, there was no statistical difference in estradiol level no matter which one was added (P > 0.05).

CONCLUSIONS

Together, our findings indicate that a novel possible mechanism to explain how stem cells restore age-related ovarian functional decline.

Type 2 Diabetes Mellitus Aggravates Complement Dysregulation and Affects Cortisol Response in Patients with Post-COVID-19

Purpose

COVID-19 viral infection results in dysregulation of the complement system and a decrease in cortisol and adrenocorticotropin hormone (ACTH) levels. This study aimed to explore the complement system, as well as cortisol and ACTH responses in patients with post-COVID-19 conditions (PCC) and type 2 diabetes mellitus (T2DM).

Patients and Methods

This study recruited 31 patients with PCC and T2DM (PCC-T2DM), 19 patients with PCC (PCC), 10 patients with T2DM (T2DM), and 10 healthy participants (control). Cortisol and ACTH in the PCC and PCC-T2DM groups were assessed using the insulin tolerance test. In the fasting state, serum samples were collected for proteomic analyses. Spearman correlation analysis was performed between proteins and cortisol, as well as between proteins and ACTH.

Results

Cortisol and ACTH levels were consistently decreased in the PCC and PCC-T2DM groups. Proteomic analyses revealed that most of the differentially abundant proteins (DAPs) in the PCC vs control and PCC-T2DM vs T2DM were involved in the coagulation and complement cascade, and the essential complement C3 was significantly upregulated in the PCC and PCC-T2DM groups when compared to their controls. Additionally, complement-related DAPs in the PCC vs control and PCC-T2DM vs T2DM were significantly correlated with cortisol and ACTH levels. In comparing PCC-T2DM samples with PCC samples, we found that upregulated DAPs were linked to the complement system and other immune system, and most DAPs were negatively correlated with cortisol and ACTH.

Conclusion

Our study revealed that T2DM exacerbated dysregulation of the complement system in patients with PCC, and significant correlations were present between complement protein levels and those of cortisol and ACTH. These results provide novel insights into the dysregulation of complement and endocrine hormones in patients with PCC and T2DM.

Hypertension in Cardiovascular and Kidney Disease: Recent Trends - Treating Two Diseases as One

BACKGROUND

Hypertension and chronic kidney disease (CKD) are closely interlinked pathophysiologic states, such that high blood pressure (BP) is an independent risk factor for disease progression in both adult and pediatric patients with kidney disorders and progressive decline in kidney function can conversely lead to worsening BP control.

SUMMARY

Hypertension in CKD is not only associated with GFR loss, but increases cardiovascular risk, which is the leading source of mortality and morbidity in this population. Given this complex relationship between hypertension, CKD, and CVD, an optimal management of BP in CKD is mandatory to break an established vicious pathophysiological cycle that leads to adverse outcomes.

KEY MESSAGES

New promising molecules for the treatment of CKD, with interesting mechanisms, particularly regarding their pathophysiological interactions with arterial hypertension, are available or under development and in the very next future they may change the way we treat high BP in CKD patients.

The Combination of Gastrodin and Gallic Acid Synergistically Attenuates AngII-Induced Apoptosis and Inflammation via Regulation of Sphingolipid Metabolism

Background

Hypertension (HTN) is closely related to endothelial damage. While tianma (TM) and gouqizi (GQZ) have the potential to be effective in the treatment of HTN in traditional Chinese medicine, their main active ingredients and whether its exert synergistic effects and the underlying mechanisms of synergistic effects are still unclear.

Objective

This study screened the active ingredients of TM and GQZ, investigated the synergistic effects of the active ingredients and explored possible mechanisms.

Methods

The potential targets and mechanisms of TM and GQZ were screened using network pharmacology, and gastrodin (GAS) and gallic acid (GA) were identified as compounds with significant antihypertensive activity. The synergistic effects of the combination of GAS and GA was assessed by measuring biomarkers of AngII-induced human umbilical vein endothelial cell (HUVECs) dysfunction model. Furthermore, the anti-apoptotic and anti-inflammatory effects were evaluated by measuring inflammatory cytokine secretion, and apoptosis-related markers. Finally, key targets of the sphingolipid signaling pathway were experimentally validated by Western blotting.

Results

In network pharmacology, the herb-pair exerted a synergetic effect by regulating sphingolipid pathways. The GAS and GA exerted synergistic protective effects in AngII-induced HUVECs injury by improving Nitric Oxide Content (NO) levels, alleviating lactate Endothelin-1 (ET-1), and Thromboxane B2 (TX-B2) release, reducing the secretion of inflammatory factors like interleukin-6 (IL-6), interleukin-1β (IL-1β), Tumor Necrosis Factor Alpha (TNF-α)), decreasing the pro-apoptotic protein BAX, and increasing the anti-apoptotic protein BCL-2. Furthermore, the results showed that the GAS and GA combination could elevate the level of S1PR1 and inhibit the expression of ROCK2 and the phosphorylation of NF-κB, which are key targets involved in sphingolipid pathways.

Conclusion

Our study revealed that the combination of GAS and GA could suppress inflammation and apoptosis, which are highly correlated with sphingolipid signaling pathways, making it a potential candidate for the treatment of HTN.

RENIN AND ANGIOTENSIN (1-7) OFFER PREDICTIVE VALUE IN PEDIATRIC SEPSIS: FINDINGS FROM PROSPECTIVE OBSERVATIONAL COHORTS

ABSTRACT

Background: Pediatric sepsis is a common and complex syndrome characterized by a dysregulated immune response to infection. Aberrations in the renin-angiotensin system (RAS) are factors in several infections of adults. However, the precise impact of RAS dysregulation in pediatric sepsis remains unclear. Methods: Serum samples were collected from a derivation cohort (58 patients with sepsis, 14 critically ill control subjects, and 37 healthy controls) and validation cohort (50 patients with sepsis, 37 critically ill control subjects, and 46 healthy controls). Serum RAS levels on day of pediatric intensive care unit admission were determined and compared with survival status and organ dysfunction. Results: In the derivation cohort, the serum renin concentration was significantly higher in patients with sepsis (3,678 ± 4,746) than that in healthy controls (635.6 ± 199.8) ( P < 0.0001). Meanwhile, the serum angiotensin (1-7) was significantly lower in patients with sepsis (89.7 ± 59.7) compared to that in healthy controls (131.4 ± 66.4) ( P < 0.01). These trends were confirmed in a validation cohort. Nonsurvivors had higher levels of renin (8,207 ± 7,903) compared to survivors (2,433 ± 3,193) ( P = 0.0001) and lower levels of angiotensin (1-7) (60.9 ± 51.1) compared to survivors (104.0 ± 85.1) ( P < 0.05). A combination of renin, angiotensin (1-7) and procalcitonin achieved a model for diagnosis with an area under the receiver operating curve of 0.87 (95% CI: 0.81-0.92). Conclusion: Circulating renin and angiotensin (1-7) have predictive value in pediatric sepsis.

Time of day affects MrgD-dependent modulation of cardiomyocyte contractility

The renin-angiotensin system (RAS) is composed of a series of peptides, receptors, and enzymes that play a pivotal role in maintaining cardiovascular homeostasis. Among the most important players in this system are the angiotensin-II and angiotensin-(1-7) peptides. Our group has recently demonstrated that alamandine (ALA), a peptide with structural and functional similarities to angiotensin-(1-7), interacts with cardiomyocytes, enhancing contractility via the Mas-related G protein-coupled receptor member D (MrgD). It is currently unknown whether this modulation varies along the distinct phases of the day. To address this issue, we assessed the ALA-induced contractility response of cardiomyocytes from mice at four Zeitgeber times (ZTs). At ZT2 (light phase), ALA enhanced cardiomyocyte shortening in an MrgD receptor-dependent manner, which was associated with nitric oxide (NO) production. At ZT14 (dark phase), ALA induced a negative modulation on the cardiomyocyte contraction. β-Alanine, an MrgD agonist, reproduced the time-of-day effects of ALA on myocyte shortening. NG-nitro-l-arginine methyl ester, an NO synthase inhibitor, blocked the increase in fractional shortening induced by ALA at ZT2. No effect of ALA on myocyte shortening was observed at ZT8 and ZT20. Our results show that ALA/MrgD signaling in cardiomyocytes is subject to temporal modulation. This finding has significant implications for pharmacological approaches that combine chronotherapy for cardiac conditions triggered by disruption of circadian rhythms and hormonal signaling.NEW & NOTEWORTHY Alamandine, a member of the renin-angiotensin system, serves critical roles in cardioprotection, including the modulation of cardiomyocyte contractility. Whether this effect varies along the day is unknown. Our results provide evidence that alamandine via receptor MrgD exerts opposing actions on cardiomyocyte shortening, enhancing, or reducing contraction depending on the time of day. These findings may have significant implications for the development and effectiveness of future cardiac therapies.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.

Effects of sacubitril-valsartan on aging-related cardiac dysfunction

Heart failure (HF) remains a huge medical burden worldwide, with aging representing a major risk factor. Here, we report the effects of sacubitril/valsartan, an approved drug for HF with reduced EF, in an experimental model of aging-related HF with preserved ejection fraction (HFpEF). Eighteen-month-old female Fisher 344 rats were treated for 12 weeks with sacubitril/valsartan (60 mg/kg/day) or with valsartan (30 mg/kg/day). Three-month-old rats were used as control. No differential action of sacubitril/valsartan versus valsartan alone, either positive or negative, was observed. The positive effects of both sacubitril/valsartan and valsartan on cardiac hypertrophy was evidenced by a significant reduction of wall thickness and myocyte cross-sectional area. Contrarily, myocardial fibrosis in aging heart was not reduced by any treatment. Doppler echocardiography and left ventricular catheterization evidenced diastolic dysfunction in untreated and treated old rats. In aging rats, both classical and non-classical renin-angiotensin-aldosterone system (RAAS) were modulated. In particular, with respect to untreated animals, both sacubitril/valsartan and valsartan showed a partial restoration of cardioprotective non-classical RAAS. In conclusion, this study evidenced the favorable effects, by both treatments, on age-related cardiac hypertrophy. The attenuation of cardiomyocyte size and hypertrophic response may be linked to a shift towards cardioprotective RAAS signaling. However, diastolic dysfunction and cardiac fibrosis persisted despite of treatment and were accompanied by myocardial inflammation, endothelial activation, and oxidative stress.

The binding of extracellular cyclophilin A to ACE2 and CD147 triggers psoriasis-like inflammation

Psoriasis is a chronic, proliferative, and inflammatory skin disease closely associated with inflammatory cytokine production. Cyclophilin A (CypA) is an important proinflammatory factor; however, its role in psoriasis remains unclear. The present data indicate that CypA levels are increased in the lesion skin and serum of patients with psoriasis, which is positively correlated with the psoriasis area severity index. Furthermore, extracellular CypA (eCypA) triggered psoriasis-like inflammatory responses in keratinocytes. Moreover, anti-CypA mAb significantly reduced pathological injury, keratinocyte proliferation, cytokine expression in imiquimod-induced mice. Notably, the therapeutic effect of anti-CypA mAb was better than that of the clinically used anti-IL-17A mAb and methotrexate. Mechanistically, eCypA binds to ACE2 and CD147 and is blocked by anti-CypA mAb. eCypA not only induces the dimerization and phosphorylation of ACE2 to trigger the JAK1/STAT3 signaling pathway for cytokine expression but also interacts with CD147 to promote PI3K/AKT/mTOR signaling-mediated keratinocyte proliferation. These findings demonstrate that the binding of eCypA to ACE2 and CD147 cooperatively triggers psoriasis-like inflammation and anti-CypA mAb is a promising candidate for the treatment of psoriasis.

Radiotracers for Molecular Imaging of Angiotensin-Converting Enzyme 2

Angiotensin-converting enzymes (ACE) are well-known for their roles in both blood pressure regulation via the renin-angiotensin system as well as functions in fertility, immunity, hematopoiesis, and many others. The two main isoforms of ACE include ACE and ACE-2 (ACE2). Both isoforms have similar structures and mediate numerous effects on the cardiovascular system. Most remarkably, ACE2 serves as an entry receptor for SARS-CoV-2. Understanding the interaction between the virus and ACE2 is vital to combating the disease and preventing a similar pandemic in the future. Noninvasive imaging techniques such as positron emission tomography and single photon emission computed tomography could noninvasively and quantitatively assess in vivo ACE2 expression levels. ACE2-targeted imaging can be used as a valuable tool to better understand the mechanism of the infection process and the potential roles of ACE2 in homeostasis and related diseases. Together, this information can aid in the identification of potential therapeutic drugs for infectious diseases, cancer, and many ACE2-related diseases. The present review summarized the state-of-the-art radiotracers for ACE2 imaging, including their chemical design, pharmacological properties, radiochemistry, as well as preclinical and human molecular imaging findings. We also discussed the advantages and limitations of the currently developed ACE2-specific radiotracers.

Targeting the epidermal growth factor receptor (EGFR/ErbB) for the potential treatment of renal pathologies

Epidermal growth factor receptor (EGFR), which is referred to as ErbB1/HER1, is the prototype of the EGFR family of receptor tyrosine kinases which also comprises ErbB2 (Neu, HER2), ErbB3 (HER3), and ErbB4 (HER4). EGFR, along with other ErbBs, is expressed in the kidney tubules and is physiologically involved in nephrogenesis and tissue repair, mainly following acute kidney injury. However, its sustained activation is linked to several kidney pathologies, including diabetic nephropathy, hypertensive nephropathy, glomerulonephritis, chronic kidney disease, and renal fibrosis. This review aims to provide a summary of the recent findings regarding the consequences of EGFR activation in several key renal pathologies. We also discuss the potential interplay between EGFR and the reno-protective angiotensin-(1-7) (Ang-(1-7), a heptapeptide member of the renin-angiotensin-aldosterone system that counter-regulates the actions of angiotensin II. Ang-(1-7)-mediated inhibition of EGFR transactivation might represent a potential mechanism of action for its renoprotection. Our review suggests that there is a significant body of evidence supporting the potential inhibition of EGFR/ErbB, and/or administration of Ang-(1-7), as potential novel therapeutic strategies in the treatment of renal pathologies. Thus, EGFR inhibitors such as Gefitinib and Erlinotib that have an acceptable safety profile and have been clinically used in cancer chemotherapy since their FDA approval in the early 2000s, might be considered for repurposing in the treatment of renal pathologies.

Biomembrane-Modified Biomimetic Nanodrug Delivery Systems: Frontier Platforms for Cardiovascular Disease Treatment

Cardiovascular diseases (CVDs) are one of the leading causes of death worldwide. Despite significant advances in current drug therapies, issues such as poor drug targeting and severe side effects persist. In recent years, nanomedicine has been extensively applied in the research and treatment of CVDs. Among these, biomembrane-modified biomimetic nanodrug delivery systems (BNDSs) have emerged as a research focus due to their unique biocompatibility and efficient drug delivery capabilities. By modifying with biological membranes, BNDSs can effectively reduce recognition and clearance by the immune system, enhance biocompatibility and circulation time in vivo, and improve drug targeting. This review first provides an overview of the classification and pathological mechanisms of CVDs, then systematically summarizes the research progress of BNDSs in the treatment of CVDs, discussing their design principles, functional characteristics, and clinical application potential. Finally, it highlights the issues and challenges faced in the clinical translation of BNDSs.

Renin Levels and Angiotensin II Responsiveness in Vasopressor-Dependent Hypotension

OBJECTIVES

The relationship between renin levels, exposure to renin-angiotensin system (RAS) inhibitors, angiotensin II (ANGII) responsiveness, and outcome in patients with vasopressor-dependent vasodilatory hypotension is unknown.

DESIGN

We conducted a single-center prospective observational study to explore whether recent RAS inhibitor exposure affected baseline renin levels, whether baseline renin levels predicted ANGII responsiveness, and whether renin levels at 24 hours were associated with clinical outcomes.

SETTING

An academic ICU in Melbourne, VIC, Australia.

PATIENTS

Forty critically ill adults who received ANGII as the primary agent for vasopressor-dependent vasodilatory hypotension who were included in the Acute Renal effects of Angiotensin II Management in Shock study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After multivariable adjustment, recent exposure to a RAS inhibitor was independently associated with a relative increase in baseline renin levels by 198% (95% CI, 36-552%). The peak amount of ANGII required to achieve target mean arterial pressure was independently associated with baseline renin level (increase by 46% per ten-fold increase; 95% CI, 8-98%). Higher renin levels at 24 hours after ANGII initiation were independently associated with fewer days alive and free of continuous renal replacement therapy (CRRT) (-7 d per ten-fold increase; 95% CI, -12 to -1).

CONCLUSIONS

In patients with vasopressor-dependent vasodilatory hypotension, recent RAS inhibitor exposure was associated with higher baseline renin levels. Such higher renin levels were then associated with decreased ANGII responsiveness. Higher renin levels at 24 hours despite ANGII infusion were associated with fewer days alive and CRRT-free. These preliminary findings emphasize the importance of the RAS and the role of renin as a biomarker in patients with vasopressor-dependent vasodilatory hypotension.

The role of p130Cas/BCAR1 adaptor protein in the pathogenesis of cardiovascular diseases: A literature review

Breast cancer anti-estrogen resistance-1 (p130Cas/BCAR1) is an adaptor protein of the cas(Cas) family. This protein regulates multiple complex pathways in different organs including bones, pancreas, and immune and cardiovascular systems. Although previous research well demonstrated the role of p130Cas/BCAR1 in different diseases especially cancers, a precise review study on the various effects of p130Cas/BCAR1 on cardiovascular diseases is missing. In this study, we reviewed mechanisms of action for p130Cas/BCAR1 impact, on cardiac embryonic development defects, hypertrophy and remodeling, pulmonary artery hypertension (PAH), and atherosclerosis. Also, we suggest feature direction for research and potential therapeutic implications. This study showed that p130Cas/BCAR1 can affect cardiovascular diseases in various mechanisms including actin stress fiber formation, attachment to focal adhesion kinase (FAK) and angiotensin II (Ang II), generation of reactive oxygen species (ROS), and growth factor signaling through amplifying receptor tyrosine kinase (RTKs).

Associations of ACE I/D and AGTR1 rs5182 polymorphisms with diabetes and their effects on lipids in an elderly Chinese population

BACKGROUND

Diabetes mellitus is generally accompanied by dyslipidaemia, but inconsistent relationships between lipid profiles and diabetes are noted. Moreover, genetic variations in insertion/deletion (I/D) polymorphisms at angiotensin-converting enzyme gene (ACE) and T/C polymorphisms in the angiotensin type 1 receptor gene (AGTR1) are related to diabetes and lipid levels, but the associations are controversial. Thus, the current research aimed to explore the effects of ACE I/D, AGTR1 rs5182 and diabetes mellitus on serum lipid profiles in 385 Chinese participants with an average age of 75.01 years.

METHODS

The ACE I/D variant was identified using the polymerase chain reaction (PCR) method, whereas the AGTR1 rs5182 polymorphism was identified using the PCR-based restriction fragment length polymorphism (PCR-RFLP) method and verified with DNA sequencing. Total cholesterol (TC), triglyceride (TG), apolipoprotein A (ApoA), apolipoprotein B (ApoB), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels were measured using routine methods, and the lipid ratios were calculated.

RESULTS

ACE I/D, but not AGTR1 rs5182, was a predictor of TG/HDL-C for the whole study population. Both ACE I/D and AGTR1 rs5182 were predictors of HDL-C and LDL-C levels in females but not in males. Moreover, in females, diabetes mellitus and ACE I/D were identified as predictors of TG and TG/HDL-C, whereas AGTR1 rs5182 and diabetes mellitus were predictors of TG/HDL-C. Moreover, diabetes mellitus and the combination of ACE I/D and AGTR1 rs5182 variations were predictors of TG and TG/HDL-C exclusively in females.

CONCLUSIONS

The results demonstrated the potential for gender-dependent interactions of ACE I/D, AGTR1 rs5182, and diabetes on lipid profiles. These findings may serve as an additional explanation for the inconsistent changes of blood lipids in individuals with diabetes mellitus, thereby offering a novel perspective for the clinical management of blood lipid levels in diabetic patients.

Epigenetic Regulation of the Renin-Angiotensin-Aldosterone System in Hypertension

Activation of the renin-angiotensin-aldosterone system (RAAS) plays an important pathophysiological role in hypertension. Increased mRNA levels of the angiotensinogen angiotensin-converting enzyme, angiotensin type 1 receptor gene, Agtr1a, and the aldosterone synthase gene, CYP11B2, have been reported in the heart, blood vessels, and kidneys in salt-sensitive hypertension. However, the mechanism of gene regulation in each component of the RAAS in cardiovascular and renal tissues is unclear. Epigenetic mechanisms, which are important for regulating gene expression, include DNA methylation, histone post-translational modifications, and microRNA (miRNA) regulation. A close association exists between low DNA methylation at CEBP-binding sites and increased AGT expression in visceral adipose tissue and the heart of salt-sensitive hypertensive rats. Several miRNAs influence AGT expression and are associated with cardiovascular diseases. Expression of both ACE and ACE2 genes is regulated by DNA methylation, histone modifications, and miRNAs. Expression of both angiotensinogen and CYP11B2 is reversibly regulated by epigenetic modifications and is related to salt-sensitive hypertension. The mineralocorticoid receptor (MR) exists in cardiovascular and renal tissues, in which many miRNAs influence expression and contribute to the pathogenesis of hypertension. Expression of the 11beta-hydroxysteroid dehydrogenase type 2 (HSD11B2) gene is also regulated by methylation and miRNAs. Epigenetic regulation of renal and vascular HSD11B2 is an important pathogenetic mechanism for salt-sensitive hypertension.

Dysregulation of the renin-angiotensin system in vascular dementia

The renin-angiotensin system (RAS) regulates systemic and cerebral blood flow and is dysregulated in dementia. The major aim of this study was to determine if RAS signalling is dysregulated in vascular dementia. We measured markers of RAS signalling in white matter underlying the frontal and occipital cortex in neuropathologically confirmed cases of vascular dementia (n = 42), Alzheimer's disease (n = 50), mixed AD/VaD (n = 50) and age-matched controls (n = 50). All cases were stratified according to small vessel disease (SVD) severity across both regions. ACE-1 and ACE-2 protein and activity was measured by ELISA and fluorogenic peptide assays respectively, and angiotensin peptide (Ang-II, Ang-III and Ang-(1-7)) levels were measured by ELISA. ACE-1 protein level and enzyme activity, and Ang-II and Ang-III, were elevated in the white matter in vascular dementia in relation to SVD severity. ACE-1 and Ang-II protein levels were inversely related to MAG:PLP1 ratio, a biochemical marker of brain tissue oxygenation that when reduced indicates cerebral hypoperfusion, in a subset of cases. ACE-2 level was elevated in frontal white matter in vascular dementia. Ang-(1-7) level was elevated across all dementia groups compared to age-matched controls but was not related to SVD severity. RAS signalling was not altered in the white matter in Alzheimer's disease. In the overlying frontal cortex, ACE-1 protein was reduced and ACE-2 protein increased in vascular dementia, whereas angiotensin peptide levels were unchanged. These data indicate that RAS signalling is dysregulated in the white matter in vascular dementia and may contribute to the pathogenesis of small vessel disease.

The Fate of Angiotensin II in Placental Tissue and Blood

The existence of a non-canonical pathway of renin-angiotensin system in the blood pressure control system has been highlighted over the past three decades. The enzymes involved in this pathway include a series of angiotensinases such as neprilysin (NEP), aminopeptidase A (APA), carboxypeptidase, and angiotensin converting enzyme 2. The physiological roles of these peptidases have been reconsidered in this study, based on the publications of other research groups and the results from our previous study, regarding the liberation of constituent amino acids from angiotensin II by placenta tissue and blood serum, respectively.

Diminazene aceturate attenuates systemic inflammation via microbiota gut-5-HT brain-spleen sympathetic axis in male mice

The sympathetic arm of the inflammatory reflex is the efferent pathway through which the central nervous system (CNS) can control peripheral immune responses. Diminazene aceturate (DIZE) is an antiparasitic drug that has been reported to exert protective effects on various experimental models of inflammation. However, the pathways by which DIZE promotes a protective immunomodulatory effects still need to be well established, and no studies demonstrate the capacity of DIZE to modulate a neural reflex to control inflammation. C57BL/6 male mice received intraperitoneal administration of DIZE (2 mg/Kg) followed by lipopolysaccharide (LPS, 5 mg/Kg, i.p.). Endotoxemic animals showed hyperresponsiveness to inflammatory signals, while those treated with DIZE promoted the activation of the inflammatory reflex to attenuate the inflammatory response during endotoxemia. The unilateral cervical vagotomy did not affect the anti-inflammatory effect of DIZE in the spleen and serum. At the same time, splenic denervation attenuated tumor necrosis factor (TNF) synthesis in the spleen and serum. Using broad-spectrum antibiotics for two weeks showed that LPS modulated the microbiota to induce a pro-inflammatory profile in the intestine and reduced the serum concentration of tryptophan and serotonin (5-HT), while DIZE restored serum tryptophan and increased the hypothalamic 5-HT levels. Furthermore, the treatment with 4-Chloro-DL-phenylalanine (pcpa, an inhibitor of 5-HT synthesis) abolished the anti-inflammatory effects of the DIZE in the spleen. Our results indicate that DIZE promotes microbiota modulation to increase central 5-HT levels and activates the efferent sympathetic arm of the inflammatory reflex to control splenic TNF production in endotoxemic mice.

Beyond blood pressure, fluid and electrolyte homeostasis - Role of the renin angiotensin aldosterone system in the interplay between metabolic diseases and breast cancer

The classical renin angiotensin aldosterone system (RAAS), as well as the recently described counter-regulatory or non-canonical RAAS have been well characterized for their role in cardiovascular homeostasis. Moreover, extensive research has been conducted over the past decades on both paracrine and the endocrine roles of local RAAS in various metabolic regulations and in chronic diseases. Clinical evidence from patients on RAAS blockers as well as pre-clinical studies using rodent models of genetic manipulations of RAAS genes documented that this system may play important roles in the interplay between metabolic diseases and cancer, namely breast cancer. Some of these studies suggest potential therapeutic applications and repurposing of RAAS inhibitors for these diseases. In this review, we discuss the mechanisms by which RAAS is involved in the pathogenesis of metabolic diseases such as obesity and type-2 diabetes as well as the role of this system in the initiation, expansion and/or progression of breast cancer, especially in the context of metabolic diseases.

Quantification of endogenous Angiotensin 1-10, 1-9, 1-8, 1-7, and 1-5 in human plasma using micro-UHPLC-MS/MS: Outlining the importance of the pre-analytics for reliable results

Angiotensin peptides (ANGs) play a central role in the renin-angiotensin-aldosterone system, rendering them interesting biomarkers associated with hypertension. Precise quantification of circulating ANGs holds the potential to assess the activity of angiotensin-converting enzyme (ACE), a key protease targeted by widely prescribed drugs, namely ACE inhibitors. This ability could pave the way for personalised medicine, offering insights into the prescription of inhibitors targeting either the proteases or the receptors within the system. Despite recent developments in liquid chromatography-mass spectrometry (LC-MS) methods for measuring circulating ANG concentrations, comprehensive stability studies of ANGs in human plasma are absent in the literature, raising concerns about the reliability of measured concentrations and their link to clinical conditions. To address this critical gap, we conducted an exhaustive evaluation of the pre-analytical stability of ANG1-10, ANG1-9, ANG1-8, ANG1-7, and ANG1-5. By employing surfactants to mitigate non-specific adsorption and a dedicated mix of protease inhibitors to limit protease activity, we established an MS-based assay for these five peptides. We used this method to quantify circulating concentrations of ANGs in the plasma of 11 healthy donors and 3 patients under kidney dialysis. Our findings revealed that ANG1-10 and ANG1-8 circulate at concentrations ranging from 1 to 10 pM in healthy subjects and exhibit a high degree of correlation. Notably, ANG1-9, ANG1-7, and ANG1-5 were undetectable in any of the 14 patients, despite a sub-picomolar limit of detection. This strikingly contrasts with the reference concentrations reported in the literature, which typically fall within the picomolar range. In light of these discrepancies, we strongly advocate for rigorous pre-analytical considerations and comprehensive stability studies to ensure reliable results. We emphasise the pivotal role of heightened pre-analytical awareness within the clinical chemistry community, and we hope for continued growth in this critical area.

Causal association between blood metabolites and risk of hypertension: a Mendelian randomization study

Background

Previous studies have indicated a strong link between blood metabolites and hypertension, however the causality of metabolites and hypertension is unknown.

Methods

Two-sample Mendelian randomization (MR) analysis was performed to assess the causal relationship between 486 blood metabolites and essential hypertension (EHT). Blood metabolite GWAS data was utilized as the exposure, with EHT GWAS data as the outcome. To further verify the results, another different source of EHT GWAS data was repeatedly analyzed. The major MR analytic approach used to determine causality was inverse variance weighted (IVW), with MR-Egger, Weighted Median, and MR-PRESSO models serving as supplements. We used the Cochran Q test to examine heterogeneity. Horizontal pleiotropy was examined using MR-Egger intercept and MR-PRESSO global test. The MR Steiger test confirmed the causal relationship between blood metabolites and EHT.

Results

In this study, nine blood metabolites associated with EHT were preliminarily identified by MR analysis, including four known metabolites (N-acetylornithine, X-12510-2-aminooctanoic acid, creatine, hexadecanedioate) and five unknown metabolites. Then another source of EHT GWAS data was repeatedly analyzed for further verification, and two overlapped metabolites (N-acetylornithine, X-12510-2-aminooctanoic acid) were found. There was a negative correlation between N-acetylornithine and EHT (OR = 0.987, 95% CI = 0.980-0.993, P = 1.01 × 10-4), Cochran's Q test suggested there was no heterogeneity (Q = 31.7586, P = 0.1331), MR-Egger intercept and MR-PRESSO global test suggested there was no horizontal pleiotropy (P > 0.05), Leave-one-out analysis indicated that no single single-nucleotide polymorphism (SNP) had a significant effect on the results, and MR Steiger test confirmed that the direction of causality was correct (P < 0.001). There was a negative correlation between X-12510-2-aminooctanoic acid and EHT (OR = 0.982, 95% CI = 0.972-0.993, P = 0.0017), and there was no evidence of heterogeneity or pleiotropy in multiple sensitivity analyses.

Conclusion

The study discovered some blood metabolites causally linked to EHT, which might lead to new understandings of the pathophysiology of hypertension.

Molecular cross-talk between long COVID-19 and Alzheimer's disease

The long COVID (coronavirus disease), a multisystemic condition following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, is one of the widespread problems. Some of its symptoms affect the nervous system and resemble symptoms of Alzheimer's disease (AD)-a neurodegenerative condition caused by the accumulation of amyloid beta and hyperphosphorylation of tau proteins. Multiple studies have found dependence between these two conditions. Patients with Alzheimer's disease have a greater risk of SARS-CoV-2 infection due to increased levels of angiotensin-converting enzyme 2 (ACE2), and the infection itself promotes amyloid beta generation which enhances the risk of AD. Also, the molecular pathways are alike-misregulations in folate-mediated one-carbon metabolism, a deficit of Cq10, and disease-associated microglia. Medical imaging in both of these diseases shows a decrease in the volume of gray matter, global brain size reduction, and hypometabolism in the parahippocampal gyrus, thalamus, and cingulate cortex. In some studies, a similar approach to applied medication can be seen, including the use of amino adamantanes and phenolic compounds of rosemary. The significance of these connections and their possible application in medical practice still needs further study but there is a possibility that they will help to better understand long COVID.

Renin-angiotensin system inhibitors positively impact on multiple aging regulatory pathways: Could they be used to protect against human aging?

The renin-angiotensin system (RAS)-a classical blood pressure regulator-largely contributes to healthy organ development and function. Besides, RAS activation promotes age-related changes and age-associated diseases, which are attenuated/abolished by RAS-blockade in several mammalian species. RAS-blockers also increase rodent lifespan. In previous work, we discussed how RAS-blockade downregulates mTOR and growth hormone/IGF-1 signaling, and stimulates AMPK activity (together with klotho, sirtuin, and vitamin D-receptor upregulation), and proposed that at least some of RAS-blockade's aging benefits are mediated through regulation of these intermediaries and their signaling to mitochondria. Here, we included RAS-blockade's impact on other aging regulatory pathways, that is, TGF-ß, NF-kB, PI3K, MAPK, PKC, Notch, and Wnt, all of which affect mitochondria. No direct evidence is available on RAS/RAS-blockade-aging regulatory pathway-mitochondria interactions. However, existing results allow to conjecture that RAS-blockers neutralize mitochondrial dysfunction by acting on the discussed pathways. The reviewed evidence led us to propose that the foundation is laid for conducting clinical trials aimed at testing whether angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB)-even at subclinical doses-offer the possibility to live longer and in better health. As ACEi and ARB are low cost and well-tolerated anti-hypertension therapies in use for over 35 years, investigating their administration to attenuate/prevent aging effects seems simple to implement.

The potential role of brain renin-angiotensin system in the neuropathology of Parkinson disease: Friend, foe or turncoat?

Parkinson disease (PD) is one of the most common neurodegenerative diseases of the brain. Of note, brain renin-angiotensin system (RAS) is intricate in the PD neuropathology through modulation of oxidative stress, mitochondrial dysfunction and neuroinflammation. Therefore, modulation of brain RAS by angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) may be effective in reducing the risk and PD neuropathology. It has been shown that all components including the peptides and enzymes of the RAS are present in the different brain areas. Brain RAS plays a critical role in the regulation of memory and cognitive function, and in the controlling of central blood pressure. However, exaggerated brain RAS is implicated in the pathogenesis of different neurodegenerative diseases including PD. Two well-known pathways of brain RAS are recognized including; the classical pathway which is mainly mediated by AngII/AT1R has detrimental effects. Conversely, the non-classical pathway which is mostly mediated by ACE2/Ang1-7/MASR and AngII/AT2R has beneficial effects against PD neuropathology. Exaggerated brain RAS affects the viability of dopaminergic neurons. However, the fundamental mechanism of brain RAS in PD neuropathology was not fully elucidated. Consequently, the purpose of this review is to disclose the mechanistic role of RAS in in the pathogenesis of PD. In addition, we try to revise how the ACEIs and ARBs can be developed for therapeutics in PD.

The possible mechanism and research progress of ACE2 involved in cardiovascular injury caused by COVID-19: a review

ACE2 is the earliest receptor discovered to mediate the entry of SARS-CoV-2. In addition to the receptor, it also participates in complex pathological and physiological processes, including regulating the RAS system, apelin, KKS system, and immune system. In addition to affecting the respiratory system, viral infections also interact with cardiovascular diseases. SARS-CoV-2 can directly invade the cardiovascular system through ACE2; Similarly, cardiovascular diseases such as hypertension and coronary heart disease can affect ACE2 levels and exacerbate the disease, and ACE2 dysregulation may also be a potential mechanism for long-term acute sequelae of COVID-19. Since the SARS CoV-2 epidemic, many large population studies have tried to clarify the current focus of debate, that is, whether we should give COVID-19 patients ACEI and ARB drug treatment, but there is still no conclusive conclusion. We also discussed potential disease treatment options for ACE2 at present. Finally, we discussed the researchers' latest findings on ACE2 and their prospects for future research.

Structural Features Influencing the Bioactive Conformation of Angiotensin II and Angiotensin A: Relationship between Receptor Desensitization, Addiction, and the Blood-Brain Barrier

The N-terminal portion of the octapeptide angiotensin II (DRVYIHPF; AngII), a vasopressor peptide that favorably binds to, and activates, AngII type 1 receptor (AT1R), has an important role in maintaining bioactive conformation. It involves all three charged groups, namely (i) the N-terminal amino group cation, (ii) the Asp sidechain anion and (iii) the Arg guanidino cation. Neutralization of any one of these three charged groups results in a substantial reduction (<5%) in bioactivity, implicating a specialized function for this cluster. In contrast, angiotensin A (ARVYIHPF; AngA) has reduced bioactivity at AT1R; however, replacement of Asp in AngII with sarcosine (N-methyl-glycine) not only restores bioactivity but increases the activity of agonist, antagonist, and inverse agonist analogues. A bend produced at the N-terminus by the introduction of the secondary amino acid sarcosine is thought to realign the functional groups that chaperone the C-terminal portion of AngII, allowing transfer of the negative charge originating at the C-terminus to be transferred to the Tyr hydroxyl-forming tyrosinate anion, which is required to activate the receptor and desensitizes the receptor (tachyphylaxis). Peptide (sarilesin) and nonpeptide (sartans) moieties, which are long-acting inverse agonists, appear to desensitize the receptor by a mechanism analogous to tachyphylaxis. Sartans/bisartans were found to bind to alpha adrenergic receptors resulting in structure-dependent desensitization or resensitization. These considerations have provided information on the mechanisms of receptor desensitization/tolerance and insights into possible avenues for treating addiction. In this regard sartans, which appear to cross the blood-brain barrier more readily than bisartans, are the preferred drug candidates.

Renin in critically ill patients

The renin-angiotensin system (RAS) constitutes one of the principal mechanisms to maintain hemodynamic and fluid homeostasis. However, most research until now on RAS primarily focuses on its relationship with hypertension and its role in critically ill hypotensive populations is not well understood. With the approval of angiotensin II (Ang II) in the United States and Europe, following a phase 3 randomized controlled trial showing efficacy in catecholamine-resistant vasodilatory shock, there is growing interest in RAS in critically ill patients. Among the fundamental components of RAS, renin acts as the initial stimulus for the entire system. In the context of hypotension, its release increases in response to low blood pressure sensed by renal baroreceptors and attenuated negative Ang II feedback loop. Thus, elevated renin could reflect disease severity and predict poor outcomes. Studies investigating this hypothesis have validated the prognostic accuracy of renin in various critically ill populations, with several reports indicating its superiority to lactate for mortality prediction. Accordingly, renin reduction has been used to assess the effectiveness of Ang II administration. Furthermore, renin holds potential to identify patients who might benefit from Ang II treatment, potentially paving the way for personalized vasopressor management. Despite these promising data, most available evidence is derived from retrospective analysis and necessitates prospective confirmation. The absence of a rapid, point-of-care and reliable renin assay presents another hurdle to its integration into routine clinical practice. This narrative review aims to describe the current understanding and future directions of renin as a biomarker during resuscitation of critically ill patients.

Dysregulation of HO-1-SIRT1 Axis is Associated with AngII-Induced Adipocyte Dysfunction

Angiotensin II (AngII), a component of the Renin-Angiotensin-Aldosterone System (RAAS), has been implicated in the dysregulation of adipose tissue function. Inhibition of AngII has been shown to improve adipose tissue function in mice with metabolic syndrome. It is well established that the Heme Oxygenase-1 (HO-1), an antioxidant improves oxidative stress and phenotypic change in adipocytes. Molecular effects of high oxidative stress include suppression of Sirtuin-1 (SIRT1), which is amenable to redox manipulations. However, the underlying mechanisms by which the Renin-Angiotensin-Aldosterone System (RAAS) exerts its metabolic effects are not fully understood. In this study, we propose that AngII-induced oxidative stress may suppress adipocyte SIRT1 through down-regulation of HO-1. Consequently, this suppression of SIRT1 may result in the up-regulation of the Mineralocorticoid Receptor (MR). We further hypothesize that the induction of HO-1 would rescue SIRT1, thereby improving oxidative stress and adipocyte phenotype. To establish this hypothesis, we conducted experiments using mouse preadipocytes treated with AngII, in the presence or absence of Cobalt Protoporphyrin (CoPP), an inducer of HO-1, and Tin Mesoporphyrin (SnMP), an inhibitor of HO-1. Our data demonstrate that treatment of mouse preadipocytes with AngII leads to increased lipid accumulation, elevated levels of superoxide and inflammatory cytokines (Interleukin-6 and Tumor necrosis factor alpha), and reduced levels of adiponectin. However, these effects were attenuated by the induction of HO-1, and this attenuation was reversed by SnMP, indicating that the beneficial effects on adipocyte phenotype are modulated by HO-1. Furthermore, our findings reveal that AngII-treated preadipocytes exhibit upregulated MR levels and suppressed SIRT1 expression, which are rescued by HO-1 induction. Following treatment with CoPP and SIRT1 siRNA in mouse preadipocytes resulted in increased lipid accumulation and elevated levels of fatty acid synthase, indicating that the beneficial effects of HO-1 are modulated through SIRT1. Our study provides evidence that HO-1 restores cellular redox balance, rescues SIRT1, and attenuates the detrimental effects of AngII on adipocytes and systemic metabolic profile.

Angiotensin II Type 2 Receptor Inhibits M1 Polarization and Apoptosis of Alveolar Macrophage and Protects Against Mechanical Ventilation-Induced Lung Injury

Angiotensin II (Ang II) is associated with macrophage polarization and apoptosis, but the role of the angiotensin type 2 receptor (AT2R) in these processes remains controversial. However, the effect of AT2Rs on alveolar macrophages and mechanical ventilation-induced lung injury has not been determined. Mechanical ventilation-induced lung injury in Sprague‒Dawley (SD) rats and LPS-stimulated rat alveolar macrophages (NR8383) were used to determine the effects of AT2Rs, selective AT2R agonists and selective AT1Rs or AT2R antagonists. Macrophage polarization, apoptosis, and related signaling pathways were assessed via western blotting, QPCR and flow cytometry. AT2R expression was decreased in LPS-stimulated rat alveolar macrophages (NR8383). Administration of the AT2R agonist CGP-42112 was associated with an increase in AT2R expression and M2 polarization, but no effect was observed upon administration of the AT2R antagonist PD123319 or the AT1R antagonist valsartan. In mechanical ventilation-induced lung injury in Sprague‒Dawley (SD) rats, the administration of the AT2R agonist C21 was associated with attenuation of the pathological damage score, lung wet/dry weight, cell count and protein content in BALF. C21 can significantly reduce proinflammatory factor TNF-α, IL-1β levels, increase anti-inflammatory factor IL-4, IL-10 levels in BALF, compared with the model group (p < 0.01). Similarly, compared with those at the same time points, the M1/M2 ratios in alveolar macrophages and apoptosis in peritoneal macrophages at 4 h, 6 h and 8 h in the mechanical ventilation models were lower after C21 administration. These findings indicated that the expression of AT2Rs in alveolar macrophages mediates M1 macrophage polarization and apoptosis and that AT2Rs play a protective role in mediating mechanical ventilation-induced lung injury.

MiR-145-5p reduced ANG II-induced ACE2 shedding and the inflammatory response in alveolar epithelial cells by targeting ADAM17 and inhibiting the AT1R/ADAM17 pathway

The excessive elevation of angiotensin II (ANG II) is closely associated with the occurrence and development of aortic dissection (AD)-related acute lung injury (ALI), through its binding to angiotensin II receptor type I (AT1R). MiR-145-5p is a noncoding RNA that can be involved in a variety of cellular physiopathological processes. Transfection with miR-145-5p was found to downregulated the expression of A disintegrin and metalloprotease 17 (ADAM17) and reduced the levels of angiotensin-converting enzyme 2 (ACE2) in lung tissue, while concurrently increasing plasma ACE2 levels in the AD combined with ALI mice. ADAM17 was proved to be a target of miR-145-5p. Transfection with miR-145-5p decreased the shedding of ACE2 and alleviated the inflammatory response induced by ANG II through targeting ADAM17 and inhibiting the AT1R/ADAM17 pathway in A549 cells. In conclusion, our present study demonstrates the role and mechanism of miR-145-5p in alleviating ANG II-induced acute lung injury, providing a new insight into miRNA therapy for reducing lung injury in patients with aortic dissection.

Novel Insights in the Hypertension Treatment & Type 2 Diabetics Induced by Angiotensin Receptor Blockers: MD Simulation Studies & Molecular Docking of Some Promising Natural Therapies

Angiotensin receptor blockers (ARBs) are commonly used to treat hypertension that target the hormonal system (renin-angiotensin system (RAS)), which regulates various physiological functions in the body. ARBs work by blocking the binding of angiotensin II to its receptor, thereby preventing a rise in blood pressure. These drugs not only normalize the overactivation of RAS but also provide protective effects against cardiovascular, renal, and type 2 diabetic patients. Inappropriate RAS activity has been linked to insulin resistance of type 2 diabetes. Olmesartan, as an ARB, was found to have a beneficial role in reducing postprandial glucose levels in type 2 diabetes. However, ARBs can cause side effects, prompting a search for new compounds that have fewer adverse effects. This study explores the potential of natural metabolites, specifically eugenol, gallic acid, myricetin, p-cymene, quercetin, and kaempferol, as ARB inhibitors compared to the current standard, olmesartan. Using in silico studies, the binding affinity of these natural substances to the ARB receptor was evaluated. The results showed that myricetin and kaempferol had affinities higher than those of olmesartan, suggesting that they could serve as promising ARB inhibitors for hypertension treatment. These natural compounds could provide an alternative approach to conventional antihypertensive drugs, which may have fewer side effects. However, more research is needed to validate the efficacy and safety of these natural compounds as antihypertensive drugs. Further in vitro and in vivo studies are needed to confirm their effectiveness and safety. This study provides a promising starting point for future investigations into the potential of natural metabolites as alternative treatments for hypertension. The findings also highlight the importance of exploring natural alternative treatments for hypertension and the protective effects of ARBs on early stage type-2 diabetics.

Adaptor protein HIP-55 promotes macrophage M1 polarization through promoting AP-1 complex activation

Overwhelming macrophage M1 polarization induced by malfunction of the renin-angiotensin-aldosterone system (RAAS) initiates inflammatory responses, which play a crucial role in various cardiovascular diseases. However, the underlying regulatory mechanism remains elusive. Here, we identified adaptor protein HIP-55 as a critical regulator of macrophage M1 polarization. The expression of HIP-55 was upregulated in M1 macrophage induced by Ang II. Overexpression of HIP-55 significantly promoted Ang II-induced macrophage M1 polarization, whereas genetic deletion of HIP-55 inhibited the Ang II-induced macrophage M1 polarization. Mechanistically, HIP-55 facilitated activator protein-1 (AP-1) complex activation induced by Ang II via promoting ERK1/2 and JNK phosphorylation. Moreover, blocking AP-1 complex activation can attenuate the function of HIP-55 in macrophage polarization. Collectively, our results reveal the role of HIP-55 in macrophage polarization and provide potential therapeutic insights for cardiovascular diseases associated with RAAS dysfunction.

Novel benzimidazole angiotensin receptor blockers with anti-SARS-CoV-2 activity equipotent to that of nirmatrelvir: computational and enzymatic studies

BACKGROUND

Hypertension worsens outcomes in SARS-CoV-2 patients. Sartans, a type of antihypertensive angiotensin receptor blocker-(ARB), reduce COVID-19 morbidity and mortality by targeting angiotensin-converting enzyme-2 (ACE2). This study aimed to evaluate the antiviral and antihypertensive effects of nirmatrelvir, commercial sartans (candesartan, losartan, and losartan carboxylic (Exp3174)), and newly synthesized sartans (benzimidazole-N-biphenyl carboxyl (ACC519C) and benzimidazole-N-biphenyl tetrazole (ACC519T)), compared to nirmatrelvir, the antiviral component of Paxlovid.

RESEARCH DESIGN AND METHODS

Surface plasmon resonance (SPR) and enzymatic studies assessed drug effects on ACE2. Antiviral abilities were tested with SARS-CoV-2-infected Vero E6 cells, and antihypertensive effects were evaluated using angiotensin II-contracted rabbit iliac arteries.

RESULTS

Benzimidazole-based candesartan and ACC519C showed antiviral activity comparable to nirmatrelvir (95% inhibition). Imidazole-based losartan, Exp3174, and ACC519T were less potent (75%-80% and 50%, respectively), with Exp3174 being the least effective. SPR analysis indicated high sartans-ACE2 binding affinity. Candesartan and nirmatrelvir combined had greater inhibitory and cytopathic effects (3.96%) than individually (6.10% and 5.08%). ACE2 enzymatic assays showed varying effects of novel sartans on ACE2. ACC519T significantly reduced angiotensin II-mediated contraction, unlike nirmatrelvir and ACC519T(2).

CONCLUSION

This study reports the discovery of a new class of benzimidazole-based sartans that significantly inhibit SARS-CoV-2, likely due to their interaction with ACE2.

Identification of 18β-glycyrrhetinic acid as an AGT inhibitor against LPS-induced myocardial dysfunction via high throughput screening

Sepsis induced myocardial dysfunction (SIMD) is a serious complication of sepsis. There is increasing evidence that the renin-angiotensin system (RAS) is activated in SIMD. Angiotensinogen (AGT) is a precursor of the RAS, and the inhibition of AGT may have significant cardiovascular benefits. But until now, there have been no reports of small molecule drugs targeting AGT. In this study, we designed a promoter-luciferase based system to screen for novel AGT inhibitors to alleviate SIMD. As a result of high-throughput screening, a total of 5 compounds from 351 medicinal herb-derived natural compounds were found inhibiting AGT. 18β-glycyrrhetinic acid (18βGA) was further identified as a potent suppressor of AGT. In vitro experiments, 18βGA could inhibit the secretion of AGT by HepG2 cells and alleviate the elevated level of mitochondrial oxidative stress in cardiomyocytes co-cultured with HepG2 supernatants. In vivo, 18βGA prolonged the survival rate of SIMD mice, enhanced cardiac function, and inhibited the damage of mitochondrial function and inflammation. In addition, the results showed that 18βGA may reduce AGT transcription by downregulating hepatocyte nuclear factor 4 (HNF4) and that further alleviated SIMD. In conclusion, we provided a more efficient screening strategy for AGT inhibitors and expanded the novel role of 18βGA as a promising lead compound in rescuing cardiovascular disease associated with RAS overactivation.

The Mas agonist CGEN-856S prevents Ang II induced cardiomyocyte hypertrophy via nitric oxide production

With the previous knowledge of the cardioprotective effects of the Angiotensin-(1-7) axis, a agonist of Mas receptor has been described, the CGEN-856S. This peptide is more stable than Ang-(1-7), and has a low binding affinity to Angiotensin II receptors. Although the cardioprotective effects of CGEN-856S were previously shown in vivo, the mechanisms behind its effects are still unknown. Here, we employed a combination of molecular biology, confocal microscopy, and genetically modified mouse with Mas deletion to investigate the CGEN-856S protective signaling in cardiomyocytes. In isolated adult ventricular myocytes, CGEN-856S induced an increase in nitric oxide (NO) production which was absent in cells from Mas knockout mice. Using western blot, we observed a significant increase in phosphorylation of AKT after treatment with CGEN-856S. In addition, CGEN-856S prevented the Ang II induced hypertrophy and the nuclear translocation of GRK5 in a culture model of rat neonatal cardiomyocytes. Blockage of Mas receptor and inhibition of the NO synthase abolished the effects of CGEN-856S on Ang II treated cardiomyocytes. In conclusion, we show that CGEN-856S acting via receptor Mas induces NO raise to block Ang II induced cardiomyocyte hypertrophy. These results indicate that CGEN-856S acts very similarly to Ang-(1-7) in cardiac myocytes, highlighting its therapeutic potential for treating cardiovascular diseases.