Renin-angiotensin-aldosterone (RAAS): The ubiquitous system for homeostasis and pathologies

The RAAS Goodfellas in Cardiovascular System

In the last two decades, the study of the renin-angiotensin-aldosterone system (RAAS) has revealed a counterregulatory protective axis. This protective arm is characterized by ACE2/Ang 1-7/MasR and Ang 1-9 that largely counteracts the classic arm of the RAAS mediated by ACE/Ang II/AT1R/aldosterone and plays an important role in the prevention of inflammation, oxidative stress, hypertension, and cardiovascular remodeling. A growing body of evidence suggests that enhancement of this counterregulatory arm of RAAS represents an important therapeutic approach to facing cardiovascular comorbidities. In this review, we provide an overview of the beneficial effects of ACE2, Ang 1-7/MasR, and Ang 1-9 in the context of oxidative stress, vascular dysfunction, and organ damage.

Higher angiotensin-converting enzyme 2 (ACE2) levels in the brain of individuals with Alzheimer's disease

Cognitive decline due to Alzheimer's disease (AD) is frequent in the geriatric population, which has been disproportionately affected by the COVID-19 pandemic. In this study, we investigated the levels of angiotensin-converting enzyme 2 (ACE2), a regulator of the renin-angiotensin system and the main entry receptor of SARS-CoV-2 in host cells, in postmortem parietal cortex samples from two independent AD cohorts, totalling 142 persons. Higher concentrations of ACE2 protein (p < 0.01) and mRNA (p < 0.01) were found in individuals with a neuropathological diagnosis of AD compared to age-matched healthy control subjects. Brain levels of soluble ACE2 were inversely associated with cognitive scores (p = 0.02) and markers of pericytes (PDGFRβ, p = 0.02 and ANPEP, p = 0.007), but positively correlated with concentrations of soluble amyloid-β peptides (Aβ) (p = 0.01) and insoluble phospho-tau (S396/404, p = 0.002). However, no significant differences in ACE2 were observed in the 3xTg-AD mouse model of tau and Aβ neuropathology. Results from immunofluorescence and Western blots showed that ACE2 protein is predominantly localized in microvessels in the mouse brain whereas it is more frequently found in neurons in the human brain. The present data suggest that higher levels of soluble ACE2 in the human brain may contribute to AD, but their role in CNS infection by SARS-CoV-2 remains unclear.

Renin-angiotensin inhibitors reduce thrombotic complications in Essential Thrombocythemia and Polycythemia Vera patients with arterial hypertension

Essential Thrombocythemia (ET) and Polycythemia Vera (PV) are chronic myeloproliferative neoplasms (MPNs) characterized by thrombotic and hemorrhagic complications, leading to a high risk of disability and mortality. Although arterial hypertension was found to be the most significant modifiable cardiovascular (CV) risk factor in the general population, little is known about its role in MPNs as well as a possible role of renin-angiotensin system inhibitors (RASi) in comparison with other anti-hypertensive treatments. We investigated a large cohort of 404 MPN adult patients, 133 diagnosed with PV and 271 with ET. Over half of the patients (53.7%) reported hypertension at MPN diagnosis. The 15-year cumulative incidence of thrombotic-adverse events (TAEs) was significantly higher in patients with hypertension (66.8 ± 10.3% vs 38.5 ± 8.4%; HR = 1.83; 95%CI 1.08-3.1). Multivariate analysis showed that PV diagnosis and hypertension were independently associated with a higher risk of developing TAEs (HR = 3.5; 95%CI 1.928-6.451, p < 0.001 and HR = 1.8; 95%CI 0.983-3.550, p = 0.05, respectively). In multivariate analysis, the diagnosis of PV confirmed a significant predictive role in developing TAEs (HR = 4.4; 95%CI 1.92-10.09, p < 0.01), also considering only MPN patients with hypertension. In addition, we found that the use of RASi showed a protective effect from TAEs both in the whole cohort of MPN with hypertension (HR = 0.46; 95%CI 0.21-0.98, p = 0.04) and in the subgroup of thrombotic high-risk score patients (HR = 0.49; 95%CI 0.24-1.01, p = 0.04). In particular, patients with ET and a high risk of thrombosis seem to benefit most from RASi treatment (HR = 0.27; 95%CI 0.07-1.01, p = 0.03). Hypertension in MPN patients represents a significant risk factor for TAEs and should be adequately treated.

Therapeutic Implications of Renin-Angiotensin System Modulators in Alzheimer's Dementia

The Renin-Angiotensin System (RAS) has attracted considerable interest beyond its traditional cardiovascular role due to emerging data indicating its potential involvement in neurodegenerative diseases, including Alzheimer's dementia (AD). This review investigates the therapeutic implications of RAS modulators, specifically focusing on angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), and renin inhibitors in AD. ACEIs, commonly used for hypertension, show promise in AD by reducing angiotensin (Ang) II levels. This reduction is significant as Ang II contributes to neuroinflammation, oxidative stress, and β-amyloid (Aβ) accumulation, all implicated in AD pathogenesis. ARBs, known for vasodilation, exhibit neuroprotection by blocking Ang II receptors, improving cerebral blood flow and cognitive decline in AD models. Renin inhibitors offer a novel approach by targeting the initial RAS step, displaying anti-inflammatory and antioxidant effects that mitigate AD degeneration. Preclinical studies demonstrate RAS regulation's favorable impact on neuroinflammation, neuronal damage, cognitive function, and Aβ metabolism. Clinical trials on RAS modulators in AD are limited, but with promising results, ARBs being more effective that ACEIs in reducing cognitive decline. The varied roles of ACEIs, ARBs, and renin inhibitors in RAS modulation present a promising avenue for AD therapeutic intervention, requiring further research to potentially transform AD treatment strategies.

Proposed mechanisms of hypertension and risk of adverse cardiovascular outcomes in LGBT communities

Hypertension (HTN), a highly prevalent public issue affecting one in two adults in the United States, has recently been shown to differentially burden individuals belonging to marginalized communities, such as the lesbian, gay, bisexual, and transgender (LGBT) communities. The minority stress theory posits that a unique combination of marginalization-related psychosocial stressors and coping behaviors may underlie the increased burden of diseases like HTN in LGBT populations. Uncontrolled or poorly managed HTN often leads to the development of adverse cardiovascular outcomes, such as heart failure (HF). Despite our understanding of minority stress theory and demonstrated associations between LGBT identities and HTN, the mechanisms whereby psychosocial stress drives HTN in LGBT populations remain unclear. This mini-review discusses the physiological systems governing blood pressure and the epidemiology of HTN across different subgroups of LGBT people. In addition, we propose mechanisms demonstrated in the general population whereby psychological stress has been implicated in elevating blood pressure that may be occurring in LGBT populations. Finally, we discuss the limitations of current studies and methodological frameworks to make suggestions for study designs to better delineate the mechanisms of psychosocial stress-related HTN in LGBT communities.

Assessing the outcomes of prescribing angiotensin converting enzyme inhibitors and angiotensin receptor blockers for COVID-19 patients

Background

Patients with heart failure were affected severely by COVID-19. Most heart failure patients are on guideline directed medical therapy, which includes ACE inhibitors (ACEI) and ARBs. These medications were controversial at the beginning of the pandemic due to their interplay with the receptor that SARS-CoV-2 binds in the lungs. We investigated the effect that ACEI and ARB had on patients with hypertension, coronary artery disease, and heart failure.

Methods

We recruited 176 patients with COVID-19 infection and cardiovascular comorbidities at the American University of Beirut Medical Center in Lebanon. Of these, 110 patients were taking ACEI or ARB and 66 were not. We collected clinical data and looked at inflammatory markers such as CRP and IL-6 and cardiac markers such as troponin T. We also reported the incidence of ARDS, sepsis, and death of each patient, and compared the 2 groups.

Results

We found that patients taking ACEI and ARB had a statistically significant decrease in levels of troponin T, IL-6, and CRP compared to patients not taking these medications (p < 0.05). We found no difference in rates of ARDS, sepsis, or death between the 2 groups.

Conclusion

Inhibition of the renin-angiotensin-aldosterone-system had no effect on the mortality of patients with COVID-19 and on their overall disease progression. However, it may be beneficial not to stop these medications as they decrease inflammation in the body and the levels of troponin, which are related to increased stress on the heart.

Inhibition of AT1R/IP3/IP3R-mediated Ca2+ release protects against calcium oxalate crystals-induced renal oxidative stress

Calcium oxalate (CaOx) stones are the most prevalent type of kidney stones. CaOx crystals can stimulate reactive oxygen species (ROS) generation and induce renal oxidative stress to promote stone formation. Intracellular Ca2+ is an important signaling molecule, and an elevation of cytoplasmic Ca2+ levels could trigger oxidative stress. Our previous study has revealed that upregulation of Ang II/AT1R promoted renal oxidative stress during CaOx exposure. IP3/IP3R/Ca2+ signaling pathway activated via Ang II/AT1R is involved in several diseases, but its role in stone formation has not been reported. Herein, we focus on the role of AT1R/IP3/IP3R-mediated Ca2+ release in CaOx crystals-induced oxidative stress and explore whether inhibition of this pathway could alleviate renal oxidative stress. NRK-52E cells were exposed to CaOx crystals pretreated with AT1R inhibitor losartan or IP3R inhibitor 2-APB, and glyoxylic acid monohydrate-induced CaOx stone-forming rats were treated with losartan or 2-APB. The intracellular Ca2+ levels, ROS levels, oxidative stress indexes, and the gene expression of this pathway were detected. Our results showed that CaOx crystals activated AT1R to promote IP3/IP3R-mediated Ca2+ release, leading to increased cytoplasmic Ca2+ levels. The Ca2+ elevation was able to stimulate NOX2 and NOX4 to generate ROS, induce oxidative stress, and upregulate the expression of stone-related proteins. 2-APB and losartan reversed the referred effects, reduced CaOx crystals deposition and alleviated tissue injury in the rat kidneys. In summary, our results indicated that CaOx crystals promoted renal oxidative stress by activating the AT1R/IP3/IP3R/Ca2+ pathway. Inhibition of AT1R/IP3/IP3R-mediated Ca2+ release protected against CaOx crystals-induced renal oxidative stress. 2-APB and losartan might be promising preventive and therapeutic agents for the treatment of kidney stone disease.

The risk factors of postoperative hypoxemia in patients with Stanford type A acute aortic dissection

Hypoxemia is one of the most common complications in patients after Stanford type A acute aortic dissection surgery. The aim of this study was to investigate the association of circulating ANG II level with postoperative hypoxemia and to identify the risk factors for postoperative hypoxemia in Stanford type A acute aortic dissection patients. In this study, 88 patients who underwent Stanford type A acute aortic dissection surgery were enrolled. Postoperative hypoxemia is defined by the oxygenation index (OI). Perioperative clinical data were collected and the serum ANG II and sACE2 levels were measured. The differences in the basic characteristics, intraoperative details, biochemical parameters, laboratory test data and clinical outcomes were compared between the hypoxemia group and the non-hypoxemia group by univariate analysis. Multivariate logistic regression analysis was performed on the variables with P < .1 in univariate analysis or that were considered clinically important to identify risk factors for postoperative hypoxemia. Twenty-five patients (28.4%) were considered to have postoperative hypoxemia (OI ≤ 200 mm Hg). The ANG II concentration remained a risk factor associated with postoperative hypoxemia [OR = 1.018, 95% CI (1.003-1.034), P = .022]. The other risk factors remaining in the logistic regression model were BMI [OR = 1.417, 95% CI (1.159-1.733), P = .001] and cTnI [OR = 1.003, 95% CI (1.000-1.005), P = .032]. Elevated levels of ANG II, BMI and cTnI are risk factors for postoperative hypoxemia in patients with Stanford type A acute aortic dissection.

Synergistic effects of hormones on structural and functional maturation of cardiomyocytes and implications for heart regeneration

The limited endogenous regenerative capacity of the human heart renders cardiovascular diseases a major health threat, thus motivating intense research on in vitro heart cell generation and cell replacement therapies. However, so far, in vitro-generated cardiomyocytes share a rather fetal phenotype, limiting their utility for drug testing and cell-based heart repair. Various strategies to foster cellular maturation provide some success, but fully matured cardiomyocytes are still to be achieved. Today, several hormones are recognized for their effects on cardiomyocyte proliferation, differentiation, and function. Here, we will discuss how the endocrine system impacts cardiomyocyte maturation. After detailing which features characterize a mature phenotype, we will contemplate hormones most promising to induce such a phenotype, the routes of their action, and experimental evidence for their significance in this process. Due to their pleiotropic effects, hormones might be not only valuable to improve in vitro heart cell generation but also beneficial for in vivo heart regeneration. Accordingly, we will also contemplate how the presented hormones might be exploited for hormone-based regenerative therapies.

Brain Renin-Angiotensin System: From Physiology to Pathology in Neuronal Complications Induced by SARS-CoV-2

Angiotensin-converting enzyme 2 (ACE2), a key enzyme in the renin-angiotensin system (RAS), is expressed in various tissues and organs, including the central nervous system (CNS). The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease-2019 (COVID-19), binds to ACE2, which raises concerns about the potential for viral infection in the CNS. There are numerous reports suggesting a link between SARS-CoV-2 infection and neurological manifestations. This study aimed to present an updated review of the role of brain RAS components, especially ACE2, in neurological complications induced by SARS-CoV-2 infection. Several routes of SARS-CoV-2 entry into the brain have been proposed. Because an anosmia condition appeared broadly in COVID-19 patients, the olfactory nerve route was suggested as an early pathway for SARS-CoV-2 entry into the brain. In addition, a hematogenous route via disintegrations in the blood-brain barrier following an increase in systemic cytokine and chemokine levels and retrograde axonal transport, especially via the vagus nerve innervating lungs, have been described. Common nonspecific neurological symptoms in COVID-19 patients are myalgia, headache, anosmia, and dysgeusia. However, more severe outcomes include cerebrovascular diseases, cognitive impairment, anxiety, encephalopathy, and stroke. Alterations in brain RAS components such as angiotensin II (Ang II) and ACE2 mediate neurological manifestations of SARS-CoV-2 infection, at least in part. Downregulation of ACE2 due to SARS-CoV-2 infection, followed by an increase in Ang II levels, leads to hyperinflammation and oxidative stress, which in turn accelerates neurodegeneration in the brain. Furthermore, ACE2 downregulation in the hypothalamus induces stress and anxiety responses by increasing corticotropin-releasing hormone. SARS-CoV-2 infection may also dysregulate the CNS neurotransmission, leading to neurological complications observed in severe cases of COVID-19. It can be concluded that the neurological manifestations of COVID-19 may be partially associated with changes in brain RAS components.

Vitamin A and retinoid signaling in the kidneys

Vitamin A (VA, retinol) and its metabolites (commonly called retinoids) are required for the proper development of the kidney during embryogenesis, but retinoids also play key roles in the function and repair of the kidney in adults. Kidneys filter 180-200 liters of blood per day and each kidney contains approximately 1 million nephrons, which are often referred to as the 'functional units' of the kidney. Each nephron consists of a glomerulus and a series of tubules (proximal tubule, loop of Henle, distal tubule, and collecting duct) surrounded by a network of capillaries. VA is stored in the liver and converted to active metabolites, most notably retinoic acid (RA), which acts as an agonist for the retinoic acid receptors ((RARs α, β, and γ) to regulate gene transcription. In this review we discuss some of the actions of retinoids in the kidney after injury. For example, in an ischemia-reperfusion model in mice, injury-associated loss of proximal tubule (PT) differentiation markers occurs, followed by re-expression of these differentiation markers during PT repair. Notably, healthy proximal tubules express ALDH1a2, the enzyme that metabolizes retinaldehyde to RA, but transiently lose ALDH1a2 expression after injury, while nearby myofibroblasts transiently acquire RA-producing capabilities after injury. These results indicate that RA is important for renal tubular injury repair and that compensatory mechanisms exist for the generation of endogenous RA by other cell types upon proximal tubule injury. ALDH1a2 levels also increase in podocytes, epithelial cells of the glomeruli, after injury, and RA promotes podocyte differentiation. We also review the ability of exogenous, pharmacological doses of RA and receptor selective retinoids to treat numerous kidney diseases, including kidney cancer and diabetic kidney disease, and the emerging genetic evidence for the importance of retinoids and their receptors in maintaining or restoring kidney function after injury. In general, RA has a protective effect on the kidney after various types of injuries (eg. ischemia, cytotoxic actions of chemicals, hyperglycemia related to diabetes). As more research into the actions of each of the three RARs in the kidney is carried out, a greater understanding of the actions of vitamin A is likely to lead to new insights into the pathology of kidney disorders and the development of new therapies for kidney diseases.

Impact of estimated plasma volume status on clinical outcomes in patients with lower extremity artery disease who underwent endovascular therapy

Lower extremity artery disease (LEAD) is an arterial occlusive disease associated with high morbidity and mortality. Estimated plasma volume status (ePVS), a marker of plasma volume expansion and contraction, is gaining attention in the field of cardiovascular diseases. However, the impact of ePVS on the clinical outcomes of patients with LEAD remains unclear. We calculated ePVS using two different formulas, Kaplan-Hakim (KH-ePVS) and Duarte (D-ePVS), in 288 patients (mean age, 73 years; 77% male) with LEAD who underwent the first endovascular therapy (EVT), and prospectively followed them up between 2014 and 2019. All patients were divided into two groups based on the median ePVS values. The primary endpoints were composite events, including all-cause death and major adverse limb events (death/MALE). The median follow-up duration was 672 days. There were 183, 40 and 65 patients in Fontaine classes II, III, and IV, respectively. The median KH-ePVS and D-ePVS was 5.96 and 5.09, respectively. The ePVS significantly increased with advancing Fontaine classes. Kaplan-Meier analysis demonstrated that the high ePVS group had higher rates of death/MALE than the low ePVS group. Multivariate Cox proportional hazard analysis revealed that each ePVS was an independent predictor for death/MALE after adjusting for confounding risk factors. The prognostic ability for death/MALE was significantly improved by adding ePVS to the basic predictors. ePVS was associated with LEAD severity and clinical outcomes, suggesting that ePVS could be an additional risk factor for death/MALE in patients with LEAD who underwent EVT. We demonstrated that the association between ePVS and the clinical outcomes of patients with LEAD. The prognostic ability for death/MALE was significantly improved by adding ePVS to the basic predictors. LEAD lower extremity artery disease, MALE major adverse limb events, PVS plasma volume status.

Association between angiotensin-converting enzyme-2 gene polymorphism (rs2106809) with severity and outcome of COVID-19 infection

PURPOSE

Genetic factors play important role in the severity of the COVID-19 infection since SARS-CoV-2 binds to the ACE2 receptor on the surface of host cells. ACE2 polymorphisms that may influence the expression of ACE2 can alter patients' susceptibility to COVID-19 infection or increase the severity of the disease. This study aimed to investigate the association between ACE2 rs2106809 polymorphism and the severity of the COVID-19 infection.

METHODS

In this cross-sectional study, ACE2 rs2106809 polymorphism was assessed in 142 COVID-19 patients. The disease was confirmed according to clinical symptoms, imaging, and laboratory findings. The severity of the disease was graded as severe versus non-severe based on the CDC. Genomic DNA was extracted from the whole blood and PCR- RFLP was performed to genotype the ACE2-rs2106809 with specific primers and Taq1 restriction enzyme.

RESULTS

G/G genotype was significantly associated with COVID-19 severity (44.4% in severe vs. 17.5% in non-severe, OR: 4.1; 95%CI: 1.8-9.5, p = 0.0007). Patients with the G/G genotype need more mechanical ventilation (p = 0.021). ACE2 expression in patients carrying the A/G genotype was higher in the severe compared to the non-severe form of the disease (2.99 ± 0.99 vs. 2.21 ± 1.1), but it was not statistically significant (p = 0.9).

CONCLUSION

The G allele and G/G genotype of ACE2 rs2106809 is associated with more severe COVID-19 and adverse disease outcomes.

All-trans retinoic acid inhibits oxidative stress via ACE2/Ang (1-7)/MasR pathway in renal tubular epithelial cells stimulated with high glucose

The aim of this study was to investigate the effects of all-trans retinoic acid (atRA) on oxidative stress in renal tubular epithelial cells induced by high glucose (HG) and its potential mechanism. We investigated the effects of atRA in HG-induced renal epithelial cell line HK-2. Seven groups were designed for this experiment: negative control, mannitol, high-glucose (HG), HG combined with a low concentration of atRA, HG combined with a middle concentration of atRA, HG combined with a high concentration of atRA, and HG combined with captopril. After 48 h of incubation, oxidative stress factor expression in the supernatant was detected by enzyme-linked immunosorbent assay. Reactive oxygen species and cell apoptosis expression were assessed by flow cytometry. NADPH oxidase, fibrosis factor, and angiotensin-converting enzyme 2/angiotensin (1-7)/mas receptor (ACE2/Ang (1-7)/MasR) pathway-related protein expressions were determined by western blot analysis. The expressions of oxidative stress factors, NADPH oxidase components, and fibrosis factors were significantly higher after HG treatment. Apoptosis of HK2 cells in the HG group was also significantly higher. AtRA could reverse the above abnormal changes in a concentration-dependent manner. HG significantly promoted the expression of ACE, Ang II, and Ang II type 1 receptor (AT1R), whereas it inhibited the expression of ACE2, Ang (1-7), and MasR. With the elevation of concentration, atRA could gradually suppress the expression of ACE, Ang II, and AT1R, but facilitate ACE2, Ang (1-7), and MasR. These results were statistically significant. AtRA could significantly inhibit oxidative stress and apoptosis of renal tubular epithelial cells induced by HG. The mechanism may inhibit the ACE/Ang II/AT1R pathway and/or activate ACE2/Ang (1-7)/MasR pathway.

No association between genetic markers and hypertension control in multiple cross-sectional studies

We aimed to assess whether genetic markers are associated with hypertension control using two cross-sectional surveys conducted in Lausanne, Switzerland. Management of hypertension was assessed as per ESC guidelines using the 140/90 or the 130/80 mm Hg thresholds. One genetic risk score (GRS) for hypertension (18 SNPs) and 133 individual SNPs related to response to specific antihypertensive drugs were tested. We included 1073 (first) and 1157 (second survey) participants treated for hypertension. The prevalence of controlled participants using the 140/90 threshold was 58.8% and 63.6% in the first and second follow-up, respectively. On multivariable analysis, only older age was consistently and negatively associated with hypertension control. No consistent associations were found between GRS and hypertension control (140/90 threshold) for both surveys: Odds ratio and (95% confidence interval) for the highest vs. the lowest quartile of the GRS: 1.06 (0.71-1.58) p = 0.788, and 1.11 (0.71-1.72) p = 0.657, in the first and second survey, respectively. Similar findings were obtained using the 130/80 threshold: 1.23 (0.79-1.90) p = 0.360 and 1.09 (0.69-1.73) p = 0.717, in the first and second survey, respectively. No association between individual SNPs and hypertension control was found. We conclude that control of hypertension is poor in Switzerland. No association between GRS or SNPs and hypertension control was found.

Kidney function and cardiovascular diseases: a large-scale observational and Mendelian randomization study

Background

Prior observational studies have found an association between kidney function and cardiovascular diseases (CVDs). However, these studies did not investigate causality. Therefore, the aim of this study is to examine the causal relationship between kidney function and CVDs.

Methods

We utilized data from the eICU Collaborative Research Database (eICU-CRD) from the years 2014-2015 to evaluate the observational association between renal failure (RF) and CVDs. To investigate the causal effects of kidney function (estimated glomerular filtration rate [eGFR] and chronic kidney disease [CKD]) and CVDs (including atrial fibrillation [AF], coronary artery disease [CAD], heart failure [HF], any stroke [AS], and any ischemic stroke [AIS]), we conducted a two-sample bidirectional Mendelian randomization (MR) analysis.

Results

In the observational analysis, a total of 157,883 patients were included. After adjusting for potential confounding factors, there was no significant association between baseline RF and an increased risk of developing CVDs during hospitalization [adjusted odds ratio (OR): 1.056, 95% confidence interval (CI): 0.993 to 1.123, P = 0.083]. Conversely, baseline CVDs was significantly associated with an increased risk of developing RF during hospitalization (adjusted OR: 1.189, 95% CI: 1.139 to 1.240, P < 0.001). In the MR analysis, genetically predicted AF was associated with an increased risk of CKD (OR: 1.050, 95% CI: 1.016 to 1.085, P = 0.004). HF was correlated with lower eGFR (β: -0.056, 95% CI: -0.090 to -0.022, P = 0.001). A genetic susceptibility for AS and AIS was linked to lower eGFR (β: -0.057, 95% CI: -0.079 to -0.036, P < 0.001; β: -0.029, 95% CI: -0.050 to -0.009, P = 0.005; respectively) and a higher risk of CKD (OR: 1.332, 95% CI: 1.162 to 1.528, P < 0.001; OR: 1.197, 95% CI: 1.023 to 1.400, P = 0.025; respectively). Regarding the reverse direction analysis, there was insufficient evidence to prove the causal effects of kidney function on CVDs. Outcomes remained consistent in sensitivity analyses.

Conclusion

Our study provides evidence for causal effects of CVDs on kidney function. However, the evidence to support the causal effects of kidney function on CVDs is currently insufficient. Further mechanistic studies are required to determine the causality.

Evidence for Impaired Renin Activity in Postural Orthostatic Tachycardia Syndrome

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) is a heterogeneous condition predominantly affecting autonomic control of the cardiovascular system. Its extensive symptom diversity implies multi-organ involvement that interacts in ways still requiring full exploration. Current understanding of POTS pathophysiology suggests alterations in the renin-angiotensin-aldosterone system as a possible contributing factor. Therefore, we investigated the relationship between the activity of the renin-angiotensin-aldosterone system and hemodynamic parameters in a cohort of POTS patients and controls recruited at a tertiary referral center.

METHODS

The case-control study included 46 patients with POTS (27 ± 9 years), and 48 healthy controls (30 ± 9 years) without orthostatic intolerance. Plasma renin activity, expressed as angiotensin I generation, and plasma aldosterone were measured by enzyme-linked immunosorbent assay and were correlated with hemodynamic parameters obtained during active standing tests.

RESULTS

Renin activity was significantly downregulated in POTS patients compared to healthy individuals (median, 3406 ng/mL vs. 9949 ng/mL, p < 0.001), whereas aldosterone concentration did not differ between POTS and healthy controls (median, 218 pmol/L vs. 218 pmol/L, p = 0.26). A significant inverse correlation between renin activity and supine and orthostatic blood pressure levels was observed in healthy individuals (p < 0.05 for all), but not in POTS patients.

CONCLUSIONS

Renin activity, but not aldosterone concentration, is downregulated in patients with POTS. Moreover, renin activity in POTS is dissociated from supine and standing blood pressure levels in contrast to healthy individuals. These findings suggest impaired renin function in POTS, which may direct future therapeutic approaches.

Probiotics: functional food ingredients with the potential to reduce hypertension

Hypertension is an increasingly pressing public health concern across the globe. It can be triggered by a variety of factors such as age and diet, as well as the stress of modern life. The traditional treatment of hypertension includes calcium ion blockers, angiotensin II receptor inhibitors and β-receptor blockers, but these drugs have at least some side effects. Recent studies have revealed that intestinal flora plays a vital role in maintaining and promoting human health. This is due to the type and amount of probiotics present in the flora. Probiotics can reduce hypertension symptoms through four mechanisms: regulating vascular oxidative stress, producing short-chain fatty acids, restoring endothelial cell function, and reducing inflammation. It has been reported that certain functional foods, using probiotics as their raw material, can modify the composition of intestinal flora, thus regulating hypertension symptoms. Consequently, utilizing the probiotic function of probiotics in conjunction with the properties of functional foods to treat hypertension is a novel, side-effect-free treatment method. This study seeks to summarize the various factors that contribute to hypertension, the mechanism of probiotics in mitigating hypertension, and the fermented functional foods with probiotic strains, in order to provide a basis for the development of functional foods which utilize probiotics as their raw material and may have the potential to reduce hypertension.

When blood pressure refuses to budge: exploring the complexity of resistant hypertension

Resistant hypertension, defined as blood pressure that remains above goal despite using three or more antihypertensive medications, including a diuretic, affects a significant proportion of the hypertensive population and is associated with increased cardiovascular morbidity and mortality. Despite the availability of a wide range of pharmacological therapies, achieving optimal blood pressure control in patients with resistant hypertension remains a significant challenge. However, recent advances in the field have identified several promising treatment options, including spironolactone, mineralocorticoid receptor antagonists, and renal denervation. In addition, personalized management approaches based on genetic and other biomarkers may offer new opportunities to tailor therapy and improve outcomes. This review aims to provide an overview of the current state of knowledge regarding managing resistant hypertension, including the epidemiology, pathophysiology, and clinical implications of the condition, as well as the latest developments in therapeutic strategies and future prospects.

Connexin 40-Mediated Regulation of Systemic Circulation and Arterial Blood Pressure

Vascular system is a complex network in which different cell types and vascular segments must work in concert to regulate blood flow distribution and arterial blood pressure. Although paracrine/autocrine signaling is involved in the regulation of vasomotor tone, direct intercellular communication via gap junctions plays a central role in the control and coordination of vascular function in the microvascular network. Gap junctions are made up by connexin (Cx) proteins, and among the four Cxs expressed in the cardiovascular system (Cx37, Cx40, Cx43, and Cx45), Cx40 has emerged as a critical signaling pathway in the vessel wall. This Cx is predominantly found in the endothelium, but it is involved in the development of the cardiovascular system and in the coordination of endothelial and smooth muscle cell function along the length of the vessels. In addition, Cx40 participates in the control of vasomotor tone through the transmission of electrical signals from the endothelium to the underlying smooth muscle and in the regulation of arterial blood pressure by renin-angiotensin system in afferent arterioles. In this review, we discuss the participation of Cx40-formed channels in the development of cardiovascular system, control and coordination of vascular function, and regulation of arterial blood pressure.

Network-Based Prediction of Side Effects of Repurposed Antihypertensive Sartans against COVID-19 via Proteome and Drug-Target Interactomes

The potential of targeting the Renin-Angiotensin-Aldosterone System (RAAS) as a treatment for the coronavirus disease 2019 (COVID-19) is currently under investigation. One way to combat this disease involves the repurposing of angiotensin receptor blockers (ARBs), which are antihypertensive drugs, because they bind to angiotensin-converting enzyme 2 (ACE2), which in turn interacts with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. However, there has been no in silico analysis of the potential toxicity risks associated with the use of these drugs for the treatment of COVID-19. To address this, a network-based bioinformatics methodology was used to investigate the potential side effects of known Food and Drug Administration (FDA)-approved antihypertensive drugs, Sartans. This involved identifying the human proteins targeted by these drugs, their first neighbors, and any drugs that bind to them using publicly available experimentally supported data, and subsequently constructing proteomes and protein-drug interactomes. This methodology was also applied to Pfizer's Paxlovid, an antiviral drug approved by the FDA for emergency use in mild-to-moderate COVID-19 treatment. The study compares the results for both drug categories and examines the potential for off-target effects, undesirable involvement in various biological processes and diseases, possible drug interactions, and the potential reduction in drug efficiency resulting from proteoform identification.

Effects of Finerenone on Cardiovascular and Chronic Kidney Diseases: A New Weapon against Cardiorenal Morbidity and Mortality-A Comprehensive Review

Patients with cardiovascular disease (CVD) and chronic kidney disease (CKD) show high rates of cardiorenal outcomes. In addition, the progression towards renal failure and cardiovascular events rises as CKD worsens. Several studies suggest that the activation of the mineralocorticoid receptor (MR) induces cardiac and renal injury, including inflammation and fibrosis. Finerenone is a novel, nonsteroidal, selective MR antagonist (MRA) which has demonstrated anti-inflammatory and anti-fibrotic effects in pre-clinical studies. Moreover, two large trials (FIDELIO-DKD and FIGARO-DKD) investigated the renal and cardiovascular outcomes in patients with mild to severe CKD in type 2 diabetes which received finerenone. On these bases, this comprehensive review aims to summarize the current knowledge regarding finerenone and its effects on CKD and the cardiovascular system, emphasizing its role in modifying cardiorenal outcomes.

Ferroptosis and multi-organ complications in COVID-19: mechanisms and potential therapies

COVID-19 is an infectious disease caused by SARS-CoV-2, with respiratory symptoms as primary manifestations. It can progress to severe illness, leading to respiratory failure and multiple organ dysfunction. Recovered patients may experience persistent neurological, respiratory, or cardiovascular symptoms. Mitigating the multi-organ complications of COVID-19 has been highlighted as a crucial part of fighting the epidemic. Ferroptosis is a type of cell death linked to altered iron metabolism, glutathione depletion, glutathione peroxidase 4 (GPX4) inactivation, and increased oxidative stress. Cell death can prevent virus replication, but uncontrolled cell death can also harm the body. COVID-19 patients with multi-organ complications often exhibit factors related to ferroptosis, suggesting a possible connection. Ferroptosis inhibitors can resist SARS-CoV-2 infection from damaging vital organs and potentially reduce COVID-19 complications. In this paper, we outline the molecular mechanisms of ferroptosis and, based on this, discuss multi-organ complications in COVID-19, then explore the potential of ferroptosis inhibitors as a supplementary intervention for COVID-19. This paper will provide a reference for the possible treatment of SARS-CoV-2 infected disease to reduce the severity of COVID-19 and its subsequent impact.

Genetic Variants within SARS-CoV-2 Human Receptor Genes May Contribute to Variable Disease Outcomes in Different Ethnicities

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved into a global pandemic, with an alarming infectivity and mortality rate. Studies have examined genetic effects on SARS-CoV-2 disease susceptibility and severity within Eurasian populations. These studies identified contrasting effects on the severity of disease between African populations. Genetic factors can explain some of the diversity observed within SARS-CoV-2 disease susceptibility and severity. Single nucleotide polymorphisms (SNPs) within the SARS-CoV-2 receptor genes have demonstrated detrimental and protective effects across ethnic groups. For example, the TT genotype of rs2285666 (Angiotensin-converting enzyme 2 (ACE2)) is associated with the severity of SARS-CoV-2 disease, which is found at higher frequency within Asian individuals compared to African and European individuals. In this study, we examined four SARS-CoV-2 receptors, ACE2, Transmembrane serine protease 2 (TMPRSS2), Neuropilin-1 (NRP1), and Basigin (CD147). A total of 42 SNPs located within the four receptors were reviewed: ACE2 (12), TMPRSS2 (10), BSG (CD147) (5), and NRP1 (15). These SNPs may be determining factors for the decreased disease severity observed within African individuals. Furthermore, we highlight the absence of genetic studies within the African population and emphasize the importance of further research. This review provides a comprehensive summary of specific variants within the SARS-CoV-2 receptor genes, which can offer a better understanding of the pathology of the SARS-CoV-2 pandemic and identify novel potential therapeutic targets.

Azelaic Acid Regulates the Renin-Angiotensin System and Improves Colitis Based on Network Pharmacology and Experimentation

Inflammatory bowel disease (IBD), which encompasses Crohn's disease and ulcerative colitis, has a complicated etiology that might be brought on by metabolic dysbiosis. Previous metabonomic studies have found a correlation between decreased azelaic acid (AzA) and IBD. Herein, data from the Metabolomics Workbench showed that the content of AzA decreased in IBD patients (PR000639) and dextran sulfate sodium (DSS)-induced mice (PR000837). The effects of AzA on IBD were then examined using a DSS-induced mouse model, and the results demonstrated that AzA alleviated clinical activity, decreased pro-inflammatory cytokine production, and reduced CD4⁺CD25⁺Foxp3⁺Treg percentages in mesenteric lymph nodes. Through network pharmacology analysis, we discovered 99 candidate IBD-associated genes that are potentially regulated by AzA. After the enrichment analysis of the candidate genes, the renin-angiotensin system (RAS) pathway was one of the most substantially enriched pathways. Additionally, AzA reversed the increased expression of important RAS components (ACE, ACE2, and MAS1L) following DSS induction, suggesting that AzA exerts therapeutic effects possibly via the RAS pathway. This study suggests that AzA may be a promising drug for treating IBD.

Elucidating glial responses to products of diabetes-associated systemic dyshomeostasis

Diabetic retinopathy (DR) is a leading cause of blindness in working age adults. DR has non-proliferative stages, characterized in part by retinal neuroinflammation and ischemia, and proliferative stages, characterized by retinal angiogenesis. Several systemic factors, including poor glycemic control, hypertension, and hyperlipidemia, increase the risk of DR progression to vision-threatening stages. Identification of cellular or molecular targets in early DR events could allow more prompt interventions pre-empting DR progression to vision-threatening stages. Glia mediate homeostasis and repair. They contribute to immune surveillance and defense, cytokine and growth factor production and secretion, ion and neurotransmitter balance, neuroprotection, and, potentially, regeneration. Therefore, it is likely that glia orchestrate events throughout the development and progression of retinopathy. Understanding glial responses to products of diabetes-associated systemic dyshomeostasis may reveal novel insights into the pathophysiology of DR and guide the development of novel therapies for this potentially blinding condition. In this article, first, we review normal glial functions and their putative roles in the development of DR. We then describe glial transcriptome alterations in response to systemic circulating factors that are upregulated in patients with diabetes and diabetes-related comorbidities; namely glucose in hyperglycemia, angiotensin II in hypertension, and the free fatty acid palmitic acid in hyperlipidemia. Finally, we discuss potential benefits and challenges associated with studying glia as targets of DR therapeutic interventions. In vitro stimulation of glia with glucose, angiotensin II and palmitic acid suggests that: 1) astrocytes may be more responsive than other glia to these products of systemic dyshomeostasis; 2) the effects of hyperglycemia on glia are likely to be largely osmotic; 3) fatty acid accumulation may compound DR pathophysiology by promoting predominantly proinflammatory and proangiogenic transcriptional alterations of macro and microglia; and 4) cell-targeted therapies may offer safer and more effective avenues for DR treatment as they may circumvent the complication of pleiotropism in retinal cell responses. Although several molecules previously implicated in DR pathophysiology are validated in this review, some less explored molecules emerge as potential therapeutic targets. Whereas much is known regarding glial cell activation, future studies characterizing the role of glia in DR and how their activation is regulated and sustained (independently or as part of retinal cell networks) may help elucidate mechanisms of DR pathogenesis and identify novel drug targets for this blinding disease.

Computer Analysis of the Inhibition of ACE2 by Flavonoids and Identification of Their Potential Antiviral Pharmacophore Site

In the present study, we investigated the antiviral activities of 17 flavonoids as natural products. These derivatives were evaluated for their in vitro antiviral activities against HIV and SARS-CoV-2. Their antiviral activity was evaluated for the first time based on POM (Petra/Osiris/Molispiration) theory and docking analysis. POM calculation was used to analyze the atomic charge and geometric characteristics. The side effects, drug similarities, and drug scores were also assumed for the stable structure of each compound. These results correlated with the experimental values. The bioinformatics POM analyses of the relative antiviral activities of these derivatives are reported for the first time.

The mechanism underlying fluoride-induced low-renin hypertension is related to an imbalance in the circulatory and local renin-angiotensin systems

The renin-angiotensin system (RAS) is an important fluid regulation system in the body, and excessive activation of the circulatory or local RAS can increase blood pressure (BP). Excess fluoride can increase BP, although the underlying mechanism related to activation of the RAS remains unclear. Thus, the aim of this study was to elucidate the role of the RAS in fluoride-induced hypertension. Markers of the circulating and local RASs related to pathological changes to the kidneys, myocardium, and aorta were measured. Fluoride reduced serum levels of renin, angiotensin II (Ang II), and angiotensin (1-7) [Ang (1-7)], and dysregulated plasma levels of aldosterone and potassium levels. Excess fluoride can damage the kidneys, myocardium, and aorta, overactivate the renal angiotensin converting enzyme (ACE)-Ang II-angiotensin type 1 receptor axis, and inhibit activation of the ACE2-Ang (1-7)-Mas axis, leading to dysregulation of alpha epithelial sodium channels and significantly increased expression of Ang II in the myocardium and aorta. Hence, excess fluoride can cause low-renin hypertension via an imbalance between the circulatory and local RASs.

Angiotensin II-Related Activation of Scleral Fibroblasts and Their Role on Retinal Ganglion Cell Death in Glaucoma

We identify the angiotensin II (AngII)-associated changes in the extracellular matrix (ECM) and the biomechanical properties of the sclera after systemic hypotension. Systemic hypotension was induced by administering oral hydrochlorothiazide. AngII receptor levels and ECM components in the sclera and biomechanical properties were evaluated based on the stress–strain relationship after systemic hypotension. The effect of inhibiting the AngII receptor with losartan was determined in the systemic hypotensive animal model and the cultured scleral fibroblasts from this model. The effect of losartan on retinal ganglion cell (RGC) death was evaluated in the retina. Both AngII receptor type I (AT-1R) and type II (AT-2R) increased in the sclera after systemic hypotension. Proteins related to the activation of fibroblasts (transforming growth factor [TGF]-β1 and TGF-β2) indicated that transformation to myofibroblasts (α smooth muscle actin [SMA]), and the major ECM protein (collagen type I) increased in the sclera after systemic hypotension. These changes were associated with stiffening of the sclera in the biomechanical analysis. Administering losartan in the sub-Tenon tissue significantly decreased the expression of AT-1R, αSMA, TGF-β, and collagen type I in the cultured scleral fibroblasts and the sclera of systemic hypotensive rats. The sclera became less stiff after the losartan treatment. A significant increase in the number of RGCs and decrease in glial cell activation was found in the retina after the losartan treatment. These findings suggest that AngII plays a role in scleral fibrosis after systemic hypotension and that inhibiting AngII could modulate the tissue properties of the sclera, resulting in the protection of RGCs.

The interplay between hypovitaminosis D and the immune dysfunction in the arteriovenous thrombotic complications of the sever coronavirus disease 2019 (COVID-19) infection

Thromboembolic complications including cerebrovascular accidents, pulmonary embolism, myocardial infarction, deep vein thrombosis and disseminating intravascular coagulopathy are serious encounters in sever coronavirus disease 2019 (COVID-19) infected patients. This worsens the prognosis and may lead to death or life long morbidities. The laboratory finding of the disturbed haemostasias and the hyperinflammatory response are almost invariably present in COVID-19 patients. Multiple treatment modalities are utilized by the healthcare professionals to overcome the cytokine storm, oxidative stress, endothelial dysfunction, and coagulopathy in these patients. The combined actions of vitamin D (VitD) as a steroid hormone with anti-inflammatory, immunomodulatory, and antithrombotic properties increase the potential of the possible involvement of hypovitaminosis D in the thromboembolic complications of COVID-19 infection, and stimulated researchers and physicians to administer VitD therapy to prevent the infection and/or overcome the disease complications. The current review highlighted the immunomodulatory, anti-inflammatory, antioxidative and hemostatic functions of VitD and its interrelation with the renin-angiotensin-aldosterone system (RAAS) pathway and the complement system. Additionally, the association of VitD deficiency with the incidence and progression of COVID-19 infection and the associated cytokine storm, oxidative stress, hypercoagulability, and endothelial dysfunction were emphasized. Normalizing VitD levels by daily low dose therapy in patients with hypovitaminosis D below (25 nmol/l) is essential for a balanced immune response and maintaining the health of the pulmonary epithelium. It protects against upper respiratory tract infections and decreases the complications of COVID-19 infections. Understanding the role of VitD and its associated molecules in the protection against the coagulopathy, vasculopathy, inflammation, oxidative stress and endothelial dysfunction in COVID-19 infection could lead to new therapeutic strategies to prevent, treat, and limit the complications of this deadly virus infection.

CTRP1: A novel player in cardiovascular and metabolic diseases

Cardiovascular diseases (CVDs) are a series of diseases induced by inflammation and lipid metabolism disorders, among others. Metabolic diseases can cause inflammation and abnormal lipid metabolism. C1q/TNF-related proteins 1 (CTRP1) is a paralog of adiponectin that belongs to the CTRP subfamily. CTRP1 is expressed and secreted in adipocytes, macrophages, cardiomyocytes, and other cells. It promotes lipid and glucose metabolism but has bidirectional effects on the regulation of inflammation. Inflammation can also inversely stimulate CTRP1 production. A vicious circle may exist between the two. This article introduces CTRP1 from the structure, expression, and different roles of CTRP1 in CVDs and metabolic diseases, to summarize the role of CTRP1 pleiotropy. Moreover, the proteins which may interact with CTRP1 are predicted through GeneCards and STRING, speculating their effects, to provide new ideas for the study of CTRP1.

Angiotensinergic neurotransmission in the bed nucleus of the stria terminalis is involved in cardiovascular responses to acute restraint stress in rats

The brain angiotensin II acting via AT₁ receptors is a prominent mechanism involved in physiological and behavioral responses during aversive situations. The AT₂ receptor has also been implicated in stress responses, but its role was less explored. Despite these pieces of evidence, the brain sites related to control of the changes during aversive threats by the brain renin-angiotensin system (RAS) are poorly understood. The bed nucleus of the stria terminalis (BNST) is a limbic structure related to the cardiovascular responses by stress, and components of the RAS system were identified in this forebrain region. Therefore, we investigated the role of angiotensinergic neurotransmission present within the BNST acting via local AT₁ and AT₂ receptors in cardiovascular responses evoked by an acute session of restraint stress in rats. For this, rats were subjected to bilateral microinjection of either the angiotensin-converting enzyme inhibitor captopril, the selective AT₁ receptor antagonist losartan, or the selective AT₂ receptor antagonist PD123319 before they underwent the restraint stress session. We observed that BNST treatment with captopril reduced the decrease in tail skin temperature evoked by restraint stress, without affecting the pressor and tachycardic responses. Local AT₂ receptor antagonism within the BNST reduced both the tachycardia and the drop in tail skin temperature during restraint. Bilateral microinjection of losartan into the BNST did not affect the restraint-evoked cardiovascular changes. Taken together, these data indicate an involvement of BNST angiotensinergic neurotransmission acting via local AT₂ receptors in cardiovascular responses during stressful situations.

Comparison of cardiocerebrovascular disease incidence between angiotensin converting enzyme inhibitor and angiotensin receptor blocker users in a real-world cohort

BACKGROUND

Both angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are known to be effective in managing cardiovascular diseases, but more evidence supports the use of an ACEI. This study investigated the difference in cardiovascular disease incidence between relatively low-compliance ACEIs and high-compliance ARBs in the clinical setting.

METHODS

Patients who were first prescribed ACEIs or ARBs at two tertiary university hospitals in Korea were observed in this retrospective cohort study for the incidence of heart failure, angina, acute myocardial infarction, cerebrovascular disease, ischemic heart disease, and major adverse cardiovascular events for 5 years after the first prescription. Additionally, 5-year Kaplan-Meier survival curves were used based on the presence or absence of statins.

RESULTS

Overall, 2,945 and 9,189 patients were prescribed ACEIs and ARBs, respectively. When compared to ACEIs, the incidence of heart failure decreased by 52% in those taking ARBs (HR [95% CI] = 0.48 [0.39-0.60], P < 0.001), and the incidence of cerebrovascular disease increased by 62% (HR [95% CI] = 1.62 [1.26-2.07], P < 0.001). The incidence of ischemic heart disease (P = 0.223) and major adverse cardiovascular events (P = 0.374) did not differ significantly between the two groups.

CONCLUSIONS

ARBs were not inferior to ACEIs in relation to reducing the incidence of cardiocerebrovascular disease in the clinical setting; however, there were slight differences for each disease. The greatest strength of real-world evidence is that it allows the follow-up of specific drug use, including drug compliance. Large-scale studies on the effects of relatively low-compliance ACEIs and high-compliance ARBs on cardiocerebrovascular disease are warranted in the future.

Blood Pressure-Lowering Effect of Fimasartan Versus Comparators: A Cross-Inference With a Systematic Review and Meta-Analysis Through a Quality Management System

PURPOSE

Fimasartan, one of the newest angiotensin receptor blockers (ARBs) available worldwide, has been investigated extensively since its initial development. Our study group conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating fimasartan and comparators for their blood pressure (BP)-lowering effect. Moreover, we employed a cross-inference (frequentist and Bayesian inference) system, which has never been used in the medical field, to confirm the results of our study. In addition, a quality management system was integrated throughout the study for data quality.

METHODS

PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, ClinicalKey, and ClinicalTrial.gov were searched for RCT studies from March 1998 to March 2022. In each study, the mean differences (MD^s) and 95% CIs were identified for reductions in clinic sitting systolic and diastolic BP (SiSBP/SiDBP) or 24-hour mean systolic BP and diastolic BP by ambulatory BP monitoring (ASBP/ADBP) from baseline between the fimasartan and comparator groups, followed by meta-analysis. A subsequent meta-analysis was performed with frequentist and Bayesian inference as a tool in the cross-checking system.

FINDINGS

Eleven RCTs with a total of 2459 subjects were included in the study. The clinic SiSBP/SiDBP-lowering effect of fimasartan was significantly greater relative to those of comparators (MD for clinic SiSBP, -2.58 mm Hg [95% CI, -4.35 to -0.81; P = 0.004]; MD for clinic SiDBP, -2.13 mm Hg [95% CI, -2.96 to -1.30; P = 0.00001]). The ASBP/ADBP-lowering effect of fimasartan was also significantly greater relative to those of comparators (MD for ASBP, -3.58 mm Hg [95% CI, -5.74 to -1.43; P = 0.001]; MD for ADBP, -1.99 mm Hg [95% CI, -3.34 to -0.63; P = 0.004]).

IMPLICATIONS

Fimasartan seems to be more effective in lowering BP than its comparators, including other ARBs. Although there is a limited amount of data and a minuscule number of study subjects available, the results of cross-inference (frequentist + Bayesian) were fairly consistent with the meta-analysis results through our quality management system.

Purinoceptor: a novel target for hypertension

Hypertension is the leading cause of morbidity and mortality globally among all cardiovascular diseases. Purinergic signalling plays a crucial role in hypertension through the sympathetic nerve system, neurons in the brain stem, carotid body, endothelium, immune system, renin-angiotensin system, sodium excretion, epithelial sodium channel activity (ENaC), and renal autoregulation. Under hypertension, adenosine triphosphate (ATP) is released as a cotransmitter from the sympathetic nerve. It mediates vascular tone mainly through P2X1R activation on smooth muscle cells and activation of P2X4R and P2YR on endothelial cells and also via interaction with other purinoceptors, showing dual effects. P2Y1R is linked to neurogenic hypertension. P2X7R and P2Y11R are potential targets for immune-related hypertension. P2X3R located on the carotid body is the most promising novel therapeutic target for hypertension. A₁R, A_2AR, A_2BR, and P2X7R are all related to renal autoregulation, which contribute to both renal damage and hypertension. The main focus is on the evidence addressing the involvement of purinoceptors in hypertension and therapeutic interventions.

Mechanism Underlying Triple VEGFR Inhibitor Tivozanib-Induced Hypertension in Mice Model

Tivozanib is a triple vascular endothelial growth factor receptor inhibitor, recently approved for the treatment of refractory advanced renal cell carcinoma. Clinical studies showed that around 46% of patients who received tivozanib suffer from hypertension in all grades. Thus, the present study was conducted to identify the role of angiotensin-II (AngII) in the mechanism underlying tivozanib-induced vascular toxicity and hypertension. C57BL/6 male mice received tivozanib (1 mg/kg) with or without losartan (10 or 30 mg/kg) for 3 weeks. Blood pressure was recorded every 3 days, and proteinuria was measured every week. On day 21, all mice were euthanized, and samples were harvested for further analysis. Tivozanib elevated blood pressure until systolic blood pressure reached 163 ± 6.6 mmHg on day 21 of treatment with low urination and high proteinuria. AngII and its receptors, endothelin-1, and oxidative stress markers were significantly increased. While nitric oxide (NO) levels were reduced in plasma and aortic tissues. AngII type 1 receptor blockade by losartan prevented these consequences caused by tivozanib and kept blood pressure within normal range. The results showed that AngII and ET-1 might be potential targets in the clinical studies and management of hypertension induced by tivozanib.

Hypertension Induces Pro-arrhythmic Cardiac Connexome Disorders: Protective Effects of Treatment

Prolonged population aging and unhealthy lifestyles contribute to the progressive prevalence of arterial hypertension. This is accompanied by low-grade inflammation and over time results in heart dysfunction and failure. Hypertension-induced myocardial structural and ion channel remodeling facilitates the development of both atrial and ventricular fibrillation, and these increase the risk of stroke and sudden death. Herein, we elucidate hypertension-induced impairment of "connexome" cardiomyocyte junctions. This complex ensures cell-to-cell adhesion and coupling for electrical and molecular signal propagation. Connexome dysfunction can be a key factor in promoting the occurrence of both cardiac arrhythmias and heart failure. However, the available literature indicates that arterial hypertension treatment can hamper myocardial structural remodeling, hypertrophy and/or fibrosis, and preserve connexome function. This suggests the pleiotropic effects of antihypertensive agents, including anti-inflammatory. Therefore, further research is required to identify specific molecular targets and pathways that will protect connexomes, and it is also necessary to develop new approaches to maintain heart function in patients suffering from primary or pulmonary arterial hypertension.

Vitamin D and estrogen steroid hormones and their immunogenetic roles in Infectious respiratory (TB and COVID-19) diseases

The role of steroid hormones against infectious diseases has been extensively studied. From immunomodulatory action to direct inhibition of microorganism growth, hormones D3 (VD3) and 17β-estradiol (E2), and the genetic pathways modulated by them, are key targets for a better understanding pathogenesis of infectious respiratory diseases (IRD) such as tuberculosis (TB) and the coronavirus disease-19 (COVID-19). Currently, the world faces two major public health problems, the outbreak of COVID-19, accounting for more than 6 million so far, and TB, more than 1 million deaths per year. Both, although resulting from different pathogens, the Mtb and the SARS-CoV-2, respectively, are considered serious and epidemic. TB and COVID-19 present similar infection rates between men and women, however the number of complications and deaths resulting from the two infections is higher in men when compared to women in childbearing age, which may indicate a role of the sex hormone E2 in the context of these diseases. E2 and VD3 act upon key gene pathways as important immunomodulatory players and supporting molecules in IRDs. This review summarizes the main roles of these hormones (VD3 and E2) in modulating immune and inflammatory responses and their relationship with TB and COVID-19.

Psychological and biological mechanisms linking trauma with cardiovascular disease risk

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, and experiences of psychological trauma have been associated with subsequent CVD onset. Identifying key pathways connecting trauma with CVD has the potential to inform more targeted screening and intervention efforts to offset elevated cardiovascular risk. In this narrative review, we summarize the evidence for key psychological and biological mechanisms linking experiences of trauma with CVD risk. Additionally, we describe various methodologies for measuring these mechanisms in an effort to inform future research related to potential pathways. With regard to mechanisms involving posttraumatic psychopathology, the vast majority of research on psychological distress after trauma and CVD has focused on posttraumatic stress disorder (PTSD), even though posttraumatic psychopathology can manifest in other ways as well. Substantial evidence suggests that PTSD predicts the onset of a range of cardiovascular outcomes in trauma-exposed men and women, yet more research is needed to better understand posttraumatic psychopathology more comprehensively and how it may relate to CVD. Further, dysregulation of numerous biological systems may occur after trauma and in the presence of posttraumatic psychopathology; these processes of immune system dysregulation and elevated inflammation, oxidative stress, mitochondrial dysfunction, renin-angiotensin system dysregulation, and accelerated biological aging may all contribute to subsequent cardiovascular risk, although more research on these pathways in the context of traumatic stress is needed. Given that many of these mechanisms are closely intertwined, future research using a systems biology approach may prove fruitful for elucidating how processes unfold to contribute to CVD after trauma.

Oxidative Stress, Antioxidants and Hypertension

As a major cause of morbidity and mortality globally, hypertension remains a serious threat to global public health. Despite the availability of many antihypertensive medications, several hypertensive individuals are resistant to standard treatments, and are unable to control their blood pressure. Regulation of the renin-angiotensin-aldosterone system (RAAS) controlling blood pressure, activation of the immune system triggering inflammation and production of reactive oxygen species, leading to oxidative stress and redox-sensitive signaling, have been implicated in the pathogenesis of hypertension. Thus, besides standard antihypertensive medications, which lower arterial pressure, antioxidant medications were tested to improve antihypertensive treatment. We review and discuss the role of oxidative stress in the pathophysiology of hypertension and the potential use of antioxidants in the management of hypertension and its associated organ damage.

Beneficial effects of Panax notoginseng (Burkill) F. H. Chen flower saponins in rats with metabolic hypertension by inhibiting the activation of the renin-angiotensin-aldosterone system through complement 3

BACKGROUND

Metabolic hypertension (MH) has become the most common type of hypertension in recent years due to unhealthy eating habits and lifestyles of people, such as over-eating alcohol, high fat, and sugar diets (ACHFSDs). Therefore, effective means to combat MH are needed. Previous studies have shown that Panax notoginseng (Burkill) F. H. Chen flower saponins (PNFS) can lower blood pressure in spontaneously hypertensive rats (SHR). However, whether it acts on MH and its mechanism of action remain unclear.  METHODS: The pharmacodynamic effects of PNFS were evaluated in rats with ACHFSDs-induced MH. The blood pressure, blood biochemical, grip strength, face temperature, vertigo time, and liver index were estimated. The histological changes in the liver and aorta were observed using hematoxylin and eosin staining. The levels of ET-1, TXB₂, NO, PGI₂, Renin, ACE, Ang II, and ALD in plasma were detected using ELISA. The levels of C3, KLF5, LXRα, and Renin in kidney tissues were measured using qRT-PCR.The expression levels of C3, KLF5, LXRα, and Renin in kidney tissues were examined using Western blotting.

RESULTS

In the present study, PNFS was found to reduce blood pressure, face temperature, and vertigo time, increase grip strength and improve dyslipidemia in rats with MH. In addition, PNFS decreased the plasma levels of ET-1 and TXB₂, elevated the levels of NO and PGI₂, and improved pathological aortic injury. Meanwhile, PNFS decreased the plasma levels of Renin, ACE, Ang II, and ALD. QRT-PCR and Western bolt showed that PNFS downregulated C3, KLF5, LXRα, and Renin protein and mRNA expression in the kidneys of rats with MH.

CONCLUSION

The finding of the present study suggested that PNFS could downregulate C3 and KLF-5 expression in rats with MH, thereby inhibiting the overactivation of the renin-angiotensin-aldosterone system, while improving vascular endothelial function and ultimately reducing blood pressure in rats with MH.

Derivation of the Immortalized Cell Line UM51-PrePodo-hTERT and Its Responsiveness to Angiotensin II and Activation of the RAAS Pathway

Recent demographic studies predict there will be a considerable increase in the number of elderly people within the next few decades. Aging has been recognized as one of the main risk factors for the world's most prevalent diseases such as neurodegenerative disorders, cancer, cardiovascular disease, and metabolic diseases. During the process of aging, a gradual loss of tissue volume and organ function is observed, which is partially caused by replicative senescence. The capacity of cellular proliferation and replicative senescence is tightly regulated by their telomere length. When telomere length is critically shortened with progressive cell division, cells become proliferatively arrested, and DNA damage response and cellular senescence are triggered, whereupon the "Hayflick limit" is attained at this stage. Podocytes are a cell type found in the kidney glomerulus where they have major roles in blood filtration. Mature podocytes are terminal differentiated cells that are unable to undergo cell division in vivo. For this reason, the establishment of primary podocyte cell cultures has been very challenging. In our present study, we present the successful immortalization of a human podocyte progenitor cell line, of which the primary cells were isolated directly from the urine of a 51-year-old male. The immortalized cell line was cultured over the course of one year (~100 passages) with high proliferation capacity, endowed with contact inhibition and P53 expression. Furthermore, by immunofluorescence-based expression and quantitative real-time PCR for the podocyte markers CD2AP, LMX1B, NPHS1, SYNPO and WT1, we confirmed the differentiation capacity of the immortalized cells. Finally, we evaluated and confirmed the responsiveness of the immortalized cells on the main mediator angiotensin II (ANGII) of the renin-angiotensin system (RAAS). In conclusion, we have shown that it is possible to bypass cellular replicative senescence (Hayflick limit) by TERT-driven immortalization of human urine-derived pre-podocyte cells from a 51-year-old African male.

Comparison of serum midkine levels between pregnant women with and without pre-eclampsia: A case-control study from a tertiary hospital

OBJECTIVE

To evaluate changes in maternal serum midkine levels in pre-eclampsia.

METHODS

This study included 40 pregnant women with pre-eclampsia and 66 healthy pregnant women in the control group. Demographic data, laboratory results, and midkine levels were compared between the groups.

RESULTS

The pre-eclampsia and control groups were similar in terms of demographics. The midkine level of pregnant women with pre-eclampsia was significantly higher than that of the controls (0.54 ± 0.23 and 0.31 ± 0.19 ng/mL, respectively, P < 0.001). According to the receiver operating characteristic analysis, the optimal cut-off value of midkine was determined as 0.37 ng/mL, at which it had 75% sensitivity and 74% specificity (area under the curve: 0.815, 95% confidence interval 0.73-0.89, P < 0.001).

CONCLUSION

The serum midkine level was significantly higher in pregnant women with pre-eclampsia. Midkine seems to be associated with complicated inflammatory processes leading to pre-eclampsia. Further study protocols can be planned to investigate the role of midkine in the prediction of pre-eclampsia as a novel marker.

Valorization of Chicken Slaughterhouse Byproducts to Obtain Antihypertensive Peptides

Hypertension (HTN) is the leading cause of premature deaths worldwide and the main preventable risk factor for cardiovascular diseases. Therefore, there is a current need for new therapeutics to manage this condition. In this regard, protein hydrolysates containing antihypertensive bioactive peptides are of increasing interest. Thus, agri-food industry byproducts have emerged as a valuable source to obtain these hydrolysates as they are rich in proteins and inexpensive. Among these, byproducts from animal origin stand out as they are abundantly generated worldwide. Hence, this review is focused on evaluating the potential role of chicken slaughterhouse byproducts as a source of peptides for managing HTN. Several of these byproducts such as blood, bones, skins, and especially, chicken feet have been used to obtain protein hydrolysates with angiotensin-converting enzyme (ACE)-inhibitory activity and blood pressure-lowering effects. An increase in levels of endogenous antioxidant compounds, a reduction in ACE activity, and an improvement of HTN-associated endothelial dysfunction were the mechanisms underlying their effects. However, most of these studies were carried out in animal models, and further clinical studies are needed in order to confirm these antihypertensive properties. This would increase the value of these byproducts, contributing to the circular economy model of slaughterhouses.

Mas receptor endocytosis and signaling in health and disease

The renin angiotensin system (RAS) plays a major role in blood pressure regulation and electrolyte homeostasis and is mainly composed by two axes mediating opposite effects. The pressor axis, constituted by angiotensin (Ang) II and the Ang II type 1 receptor (AT1R), exerts vasoconstrictor, proliferative, hypertensive, oxidative and pro-inflammatory actions, while the depressor/protective axis, represented by Ang-(1-7), its Mas receptor (MasR) and the Ang II type 2 receptor (AT2R), opposes the actions elicited by the pressor arm. The MasR belongs to the G protein-coupled receptor (GPCR) family. To avoid receptor overstimulation, GPCRs undergo internalization and trafficking into the cell after being stimulated. Then, the receptor may induce other signaling cascades or it may even interact with other receptors, generating distinct biological responses. Thus, control of a GPCR regarding space and time affects the specificity of the signals transduced by the receptor and the ultimate cellular response. The present chapter is focused on the signaling and trafficking pathways of MasR under physiological conditions and its participation in the pathogenesis of numerous brain diseases.

mRNA Metabolism and Hypertension

Hypertension is the most frequent cardiovascular risk factor all over the world. It remains a leading contributor to the risk of cardiovascular events and death. In the year 2015, about 1.5 billion of adult people worldwide had hypertension (as defined by office systolic blood pressure ≥ 140 mmHg or office diastolic blood pressure ≥ 90 mmHg). Moreover, the number of hypertensive patients with age ranging from 30 to 79 years doubled in the last 30 years (from 317 million men and 331 million women in the year 1990 to 652 million men and 626 million women in 2019) despite stable age-standardized prevalence worldwide. Despite such impressive growth, the proportion of controlled hypertension is very low. A better understanding of the pathogenesis of hypertension may contribute to the development of innovative therapeutic strategies. In this context, alterations of the messenger RNA metabolism have been recently evaluated as contributors to the pathogenesis of hypertension, and pharmacological modulation of RNA metabolism is under investigation as potential and novel therapeutic armamentarium in hypertension.

Human ACE-2, MCP1 and micro-RNA 146 as Novel Markers for COVID- 19 Affection and Severity

BACKGROUND & AIMS

Coronavirus disease - 2019 (COVID-19) is a major pandemic that causes high morbidity and mortality rates.

AIM OF THIS STUDY

to detect the relations between many risk factors, ACE-2, MCP-1, Micro RNA 146 gene expression, and COVID-19 infection and disease severity.

METHODS

This study was carried out on 165 cases of COVID-19 and 138 controls. ACE2 and MCP1 levels were measured in COVID-19 cases and control by ELISA and micro-RNA-146 expression by PCR.

RESULTS

We found an increased blood level of ACE2 and MCP1 in COVID- 19 patients than in healthy persons and a significant down-regulation of micro-RNA 146 gene expression in cases than in controls. There was a significant correlation between increased blood level of ACE2, regulation of micro-RNA 146 gene expression and severity of lung affection, a significant correlation was found between increased blood level of MCP1 and thrombosis in COVID-19 patients. Neurological complications were significantly correlated with more viral load, more ACE2 blood level, and down regulation of micro RNA146 expression.

CONCLUSION

High viral load, increased blood level of ACE2, and down-regulation of micro-RNA 146 expression are associated with more severe lung injury and the presence of neurologic complications like convulsions and coma in COVID-19 Egyptian patients.

Summary of Known Genetic and Epigenetic Modification Contributed to Hypertension

Hypertension is a multifactorial disease due to a complex interaction among genetic, epigenetic, and environmental factors. Characterized by raised blood pressure (BP), it is responsible for more than 7 million deaths per annum by acting as a leading preventable risk factor for cardiovascular disease. Reports suggest that genetic factors are estimated to be involved in approximately 30 to 50% of BP variation, and epigenetic marks are known to contribute to the initiation of the disease by influencing gene expression. Consequently, elucidating the genetic and epigenetic mediators associated with hypertension is essential for better discernment of its pathophysiology. By deciphering the unprecedented molecular hypertension basis, it could help to unravel an individual's inclination towards hypertension which eventually could result in an arrangement of potential strategies for prevention and therapy. In the present review, we discuss known genetic and epigenetic drivers that contributed to the hypertension development and summarize the novel variants that have currently been identified. The effect of these molecular alterations on endothelial function was also presented.

The Surging Mechanistic Role of Angiotensin Converting Enzyme 2 in Human Pathologies: A Potential Approach for Herbal Therapeutics

Advancements in biological sciences revealed the significant role of angiotensin-converting enzyme 2 (ACE2), a key cell surface receptor in various human pathologies. ACE2 is a metalloproteinase that not only functions in the regulation of Angiotensin II but also possesses some non-catalytic roles in the human body. There is considerable uncertainty regarding its protein expression, despite its presence in virtually all organs. The level of ACE2 expression and its subcellular localisation in humans may be a key determinant of susceptibility to various infections, symptoms, and outcomes of numerous diseases. Therefore, we summarize the distribution and expression pattern of ACE2 in different cell types related to all major human tissues and organs. Moreover, this review constitutes accumulated evidences of the important resources for further studies on ACE2 Inhibitory capacity via different natural compounds in order to understand its mechanism as the potential drug target in disease pathophysiology and to aid in the development of an effective therapeutic approach towards the various diseases.