Hypertension and cardiac failure in its various forms

Evidence for Aldosterone Antagonism in Heart Failure

Activation of the renin-angiotensin-aldosterone system is the ultimate pathophysiological hallmark in heart failure. Though aldosterone primarily appears to regulate electrolyte homeostasis by acting on distal nephrons in the kidneys, its effects are far-reaching across the cardiovascular system as its receptors are also expressed in vascular smooth muscle cells, endothelial cells, macrophages and cardiomyocytes. Aldosterone excess leads to vascular stiffness, vasoconstriction, endothelial dysfunction, inflammation, oxidative stress, cardiac fibrosis and hypertrophy, atherogenesis and thrombosis. Hence, aldosterone antagonism is an attractive proposition for heart failure management. The first-generation non-selective mineralocorticoid receptor antagonist spironolactone produced a spectacular reduction of cardiovascular outcomes in the seminal RALES study, while the selective second-generation congener eplerenone boasts two positive studies: EPHESUS and EMPHASIS-HF. The TOPCAT trial indicated that a specific subgroup of patients with heart failure with preserved ejection fraction may benefit from targeted therapy of mineralocorticoid receptor antagonists. Newer-generation non-steroidal mineralocorticoid antagonists and aldosterone synthase inhibitors are being evaluated in randomised trials.

Renal Inflammation, Oxidative Stress, and Metabolic Abnormalities During the Initial Stages of Hypertension in Spontaneously Hypertensive Rats

Background: Hypertension is a major cause of mortality worldwide. The kidneys play a crucial role in regulating blood pressure and fluid volume. The relationship between the kidneys and hypertension is complex, involving factors such as the renin-angiotensin system, oxidative stress, and inflammation. This study aims to assess the levels of inflammatory markers, oxidative stress, and metabolic factors in the kidneys, focusing on their potential role in early renal damage and their association with the development of hypertension. Methods: This study was designed to compare the levels of selected inflammatory markers, e.g., interleukins, tumor necrosis factor-α (TNF-α), transforming growth factor, and serine/threonine-protein (mTOR); oxidative stress markers such as malondialdehyde, sulfhydryl group, and glucose (GLC); and metabolic markers among other enzymes, such as alanine transaminase (ALT), aspartate transaminase (AST), hexokinase II (HK-II), and hypoxia-inducible factor-1α (HIF-1α), as well as creatinine in the kidneys of spontaneously hypertensive rats (SHR/NCrl, n = 12) and Wistar Kyoto rats (WKY/NCrl, n = 12). Both juvenile (5 weeks old) and maturing (10 weeks old) specimens were examined using spectrophotometric methods, e.g., ELISA. Results: Juvenile SHRs exhibited reduced renal levels of all studied cytokines and chemokines, with lower oxidative stress and deficits in the mTOR and HK-II levels compared to the age-matched WKYs. Maturing SHRs showed increased renal levels of interleukin-1β (IL-1β), IL-6, IL-18, and TNF-α, alongside elevated carbonyl stress and increased HIF-1α as opposed to their control peers. The levels of all other studied markers were normalized in these animals, except for ALT (increased), ALP, and GLC (both reduced). Conclusions: This study underscores the significant impact of inflammatory, oxidative stress, and metabolic marker changes on renal function. Juvenile SHRs display lower marker levels, indicating an immature immune response and potential subclinical kidney damage that may contribute to hypertension development. In contrast, mature SHRs exhibit chronic inflammation, oxidative dysregulation, and metabolic disturbances, suggesting cellular damage. These changes create a feedback loop that worsens kidney function and accelerates hypertension progression, highlighting the kidneys' crucial role in both initiating and exacerbating this condition.

Perceived barriers and enablers influencing health extension workers toward home-based hypertension screening in rural northwest Ethiopia: interpretive descriptive study

BACKGROUND

Hypertension, a major but modifiable risk factor for cardiovascular diseases, is a global health problem including Ethiopia. In a limited infrastructure task sharing of hypertension screening for community health workers is a feasible strategy to improve hypertension management. Recent finding have shown that trained health extension workers (HEWs) can identify high blood pressure, which was effective and feasible. Identifying barriers and enablers for home-based hypertension screening by HEWs is crucial for its implementation. This study aimed to explore barriers and enablers that influence health extension workers' home-based hypertension screening in the community.

METHODS

The interpretive descriptive design was implemented. In-depth interviews were conducted during October, 2020. A total of 26 participants including HEWs, supervisors, and heads of district health office were purposively selected. They were asked to describe their perception toward home-based hypertension screening by the HEWs. The interviews were audio-recorded, transcribed verbatim into Amharic, and translated into English. The transcripts were coded and themes were identified. Thematic approach was used for data analysis.

RESULTS

The participants identified key perceived barriers and enablers of HEWs home-based hypertension screening. The most common barriers were a lack of hypertension training, blood pressure measuring devices, blood pressure guidelines and manuals, skilled HEWs, financial incentives, and poor community awareness of the disease. The most common enablers were support from community leaders, presence of functional development army and community trust for HEWs, presence of routine campaign on vaccination and community based health insurance, and an integrated health system.

CONCLUSIONS

Our findings have implications for the HEWs' ongoing implementation of home-based hypertension screening. Successful implementation of this strategy requires scaling up of hypertension training programs for health extension workers and their supervisors, provision of standardized protocols, provision of adequate blood pressure measuring equipment, and regular supportive supervision.

The association between angiotensin II type 1 receptor A1166C gene polymorphism and the risk of essential hypertension: a meta-analysis

Background

Since first reported having the association with essential hypertension, angiotensin II type 1 receptor (AT1R) A1166C was globally investigated worldwide. However, controversy was found. Furthermore, previous meta-analyses did not adequate to clarify the precise correlation due to some limitations. Therefore, we aimed to perform a meta-analysis concerning the association between AT1R A1166C single-nucleotide polymorphism (SNP) and the risk of essential hypertension with eliminating the limitations of previous studies.

Methods

A meta-analysis was conducted from February to March 2019. Some information related to sample size of hypertension and control groups and genotype frequencies of hypertension and control groups were extracted from each study. Data were analyzed using fixed or random effect model to determine the overall correlation.

Results

A total of 45 papers consisting of 11911 cases and 1340 controls were enrolled for the study. Our overall analysis showed that C allele and AC genotype of AT1R A1166C was associated with 1.18-fold and 1.15-fold respectively increased risk of essential hypertension, while the decreased risk of essential hypertension was observed in A allele and AA genotype. In sub-group analysis, increased risk of essential hypertension was found in C allele, AC genotype, and CC genotype of both Asian population and PCR-RFLP sub-groups, while decreased risk was observed in A allele and AA genotype.

Conclusions

Our meta-analysis reveals that AT1R A1166C remains a valuable SNP having an association with the risk of essential hypertension.

Short‑term vagus nerve stimulation reduces myocardial apoptosis by downregulating microRNA‑205 in rats with chronic heart failure

Previous studies have reported that short-term vagus nerve stimulation (VNS) improves cardiac function in rats with chronic heart failure (CHF). The molecular mechanisms are unclear. The potential effect of microRNA (miR)-205 in apoptosis of short-term VNS was examined. A total of 3 weeks after inducing CHF, the rats were divided into three groups: Sham stimulation in sham operated rats, sham stimulation in CHF rats (CHF-SS), and treated with VNS in CHF rats (CHF-VNS). The right vagus nerve of the neck was stimulated for 72 h in CHF rats with rectangular pulses of 40 msec duration at 1 Hz and 5 V. miR-205 was focused on, which exhibited differential expression in the miRNA microarray analysis of CHF rats, and the effects of VNS on apoptosis were examined. It was verified that the expression level of miR-205 in the CHF-SS group was increased, and the expression was reduced in the CHF-VNS group. Furthermore, mimics or inhibitor of miR-205 was transfected into H9c2 to investigate its function on apoptosis. Baculoviral IAP repeat-containing protein 2 (Birc2) was confirmed a target of miR-205 through a dual luciferase reporter assay and western blotting. It was demonstrated that downregulated miR-205 decreased apoptosis in H9c2 cells. The apoptosis-associated proteins were further detected in H9c2 cells and rat tissue. The mRNA and protein expression levels of caspase-3 and Bcl-2-associated X protein were decreased in the CHF-VNS group, the expression of Birc2 and B-cell lymphoma 2 were increased. The results were consistent with the in vitro study in the miR-205 inhibitor group. The present study demonstrated that short-term VNS decreased apoptosis by downregulating miR-205 in rats with CHF. Therefore, the results of the present study provide basic evidence for short-term VNS in the clinical treatment of CHF.

Changes in Adherence to Non-Pharmacological Guidelines for Hypertension

This study aimed to compare levels of adherence to non-pharmacological guidelines between patients with and without hypertension diagnoses, and examined temporal changes in adherence during recent decades. We used data from the Korean National Health and Nutrition Examination Survey (1998-2012), including 13,768 Korean hypertensive patients aged ≥ 30 years who were categorized according to the presence or absence of a hypertension diagnosis, based on blood pressure and self-reported information. Adherence to the guidelines was calculated for 6 components, including dietary and lifestyle habits. A multivariable generalized linear regression model was used. The proportion of hypertensive patients aware of their condition increased from 33.4% in 1998 to 74.8% in 2012 (p < 0.001), although these increments plateaued during recent survey years. Patients with hypertension diagnoses were older, and more likely to be female,and have lower education levels than those without hypertension diagnoses, for most survey years. Overall adherence levels were poor (mean score 2 of 6), and levels of adherence to non-pharmacological habits did not significantly differ between patients with and without hypertension diagnoses. However, overall adherence levels improved significantly among patients with hypertension diagnoses: from 2.09 in 1998 to 2.27 in 2012 (p = 0.007), particularly regarding sufficient vegetable/seaweed consumption (p = 0.03), maintaining a normal weight (p = 0.03), and avoidance of smoking (p < 0.001). Awareness of hypertension is increasing, but hypertensive Korean patients demonstrate poor overall adherence to non-pharmacological hypertension management guidelines. These findings suggest that well-planned education programs should be continued after hypertension is diagnosed.

Multiple and large simple renal cysts are associated with prehypertension and hypertension

Although simple renal cysts are thought to be related to hypertension, no reports have examined the relationship between simple renal cysts and prehypertension. Here, we evaluated the effects of simple renal cysts on prehypertension and hypertension and the role of serum renin levels in the cyst-related prehypertension/hypertension in adults. A total of 14,995 patients were enrolled and divided into normotension, prehypertension, and hypertension groups. Simple renal cysts were classified into different categories based on number (1 vs. ≥ 2 cm) and size (<2 vs. ≥ 2 cm). In multivariate analysis, simple renal cysts were independently related to prehypertension/hypertension. Two or more simple renal cysts or cyst of ≥ 2 cm were independently associated with prehypertension/hypertension. However, the association between cyst of ≥ 2 cm and prehypertension/hypertension disappeared after further adjusting for serum renin level in an exposure-matched subgroup analysis. Thus, the presence of two or more simple renal cysts and cyst of ≥ 2 cm were the important determinants of prehypertension and hypertension in adults. One possible mechanism of cyst-related prehypertension/hypertension may be related to an increased serum renin level. We recommend close monitoring of blood pressure routinely among patients with two or more simple renal cysts.

The angiotensin receptor blocker and PPAR-γ agonist, telmisartan, delays inactivation of voltage-gated sodium channel in rat heart: novel mechanism of drug action

Telmisartan is an angiotensin II receptor blocker and partial peroxisome proliferator-activated receptor gamma agonist that modulates the renin-angiotensin-aldosterone system. It is used primarily to manage hypertension, diabetic nephropathy, and congestive heart failure. Recent studies have reported that myocardial infarction (MI) has occurred in telmisartan-treated patients. The purpose of the study was to investigate the specific conditions and underlying mechanisms that may result in telmisartan-induced MI. We evaluated the effect of telmisartan on whole hearts, cardiomyocytes, and cardiac sarcolemmal ion channels. Hearts of 8-week-old male Sprague-Dawley rats were perfused with 3, 10, 30, or 100 μM telmisartan or losartan or with normal Tyrode's solution (control) for 3 h. We found that telmisartan induced myocardial infarction, with an infarct size of 21 % of the total at 30 μM (P < 0.0001) and 63 % of the total area at 100 μM (P < 0.001). Telmisartan also induced cardiac dysfunction (e.g., decreased heart rate, diminished coronary flow, hypercontracture, and arrhythmia). Confocal microscopy demonstrated that 30 μM telmisartan significantly elevated the intracellular Ca(2+) level, leading to hypercontracture and cell death. Patch clamp analysis of isolated cardiomyocytes revealed that telmisartan induced Na(+) overload by slowing the inactivation of voltage-gated Na(+) current (I (Na)), activating the reverse mode of Na(+)-Ca(2+) exchanger activity, and causing Ca(2+) overload. Telmisartan significantly delayed the inactivation of the voltage-gated Na(+) channel, causing cytosolic Na(+) overload, prolonged action potential duration, and subsequent Ca(2+) overload. Above 30 μM, telmisartan may potentially cause cardiac cell death and MI.

Associations of LV hypertrophy with prevalent and incident valve calcification: Multi-Ethnic Study of Atherosclerosis

OBJECTIVES

The aim of this study was to evaluate the relationship between percentage of predicted left ventricular mass (%PredLVM) and valve calcification in the MESA (Multi-Ethnic Study of Atherosclerosis) study.

BACKGROUND

Cardiac valve calcification has been associated with left ventricular hypertrophy (LVH), which portends cardiovascular events. However, this relationship and its mediators are poorly understood.

METHODS

The MESA study is a longitudinal cohort study of men and women 45 to 84 years of age without clinical cardiovascular disease in whom serial cardiac magnetic resonance and computed tomography imaging were performed. The relationships between baseline %PredLVM and the prevalence, severity, and incidence of aortic valve (AVC) and mitral annulus calcification (MAC) were determined by regression modeling.

RESULTS

Prevalent AVC was observed in 630, and MAC was observed in 442 of 5,042 subjects (median 55.9 and 71.1 Agatston units, respectively). After adjustment for age, sex, body mass index (BMI), ethnicity, socioeconomic status, physical activity, diabetes, cholesterol levels, blood pressure, smoking, kidney function, serum lipids, and antihypertensive and statin medications, %PredLVM was associated with prevalent AVC (odds ratio [OR]: 1.18/SD increase in %PredLVM [95% confidence interval (CI): 1.08 to 1.30]; p = 0.0004) and MAC (OR: 1.18 [95% CI: 1.06 to 1.32]; p = 0.002). Similarly, %PredLVM was associated with increased severity of prevalent AVC (risk difference = 0.26 [95% CI: 0.15 to 0.38]; p < 0.0001) and MAC (risk difference = 0.20 [95% CI: 0.03 to 0.37]; p = 0.02). During follow-up (mean 2.4 ± 0.9 years), 153 subjects (4%) developed AVC, and 198 (5%) developed MAC. The %PredLVM was associated with incident AVC (OR: 1.24 [95% CI: 1.04 to 1.47]; p = 0.02) and MAC (OR: 1.18 [95% CI: 1.01 to 1.40]; p = 0.04). Further adjustment for inflammatory markers and coronary artery calcification did not attenuate these associations. Specifically, concentric LVH most strongly predicted incident valve calcification.

CONCLUSIONS

Within the MESA cohort, LVH was associated with prevalence, severity, and incidence of valve calcification independent of hypertension and other identified confounders.

The meaning of hypokalemia in heart failure

Maintenance of normal potassium (K(+)) homeostasis has become an increasingly important limiting factor in the therapy of heart failure (HF). With the application of loop diuretics and digoxin, hypokalemia has become a frequent and feared side effect of treatment. Low serum K(+) in HF may be also a marker of increased neurohormonal activity and disease progression. To gain the maximum benefit from treatment, we need to individualize drug use and carefully monitor electrolytes. Symptomatic HF patients (New York Heart Association class III-IV) should be prescribed the lowest dose of diuretic necessary to maintain euvolemia. Mild hypokalemia may be corrected by the use of aldosterone receptor antagonists such as spironolactone or eplerenone. However, a more severe hypokalemia should preferably be corrected using K(+) supplement. Serum K levels should be frequently checked and maintained between 4.0 and 5.5 mEq/l (mmol/l).

How should we manage heart failure developing in patients already treated with angiotensin-converting enzyme inhibitors and beta-blockers for hypertension, diabetes or coronary disease?

An increasing number of patients in the community are being treated with angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and beta-blockers for hypertension, coronary disease or diabetic renal and vascular complications. Some of these patients will develop heart failure despite such treatment. Based on data from hypertension trials it can be estimated that approximately 5% of treated patients will develop heart failure over 5 years. It is unclear whether patients developing heart failure on and off ACE-inhibitors or beta-blockers, respectively, at the time of heart failure diagnosis have similar prognosis.Treatment options for patients developing heart failure while already treated with ACE inhibitors/ARBs and beta-blockers are very limited if current heart failure guidelines are followed. In this review possible strategies are outlined and important areas for research are identified. It is suggested that trials are designed specifically to address prognosis and treatment in this growing population.

Angiotensin II-induced upregulation of AT(1) receptor expression: sequential activation of NF-kappaB and Elk-1 in neurons

It has been clearly established that increased circulating angiotensin II (ANG II) with concurrent upregulation of brain and peripheral ANG II type 1 receptors (AT(1)R) are important mediators in the pathophysiology of several diseases characterized by sympatho-excitation. In an effort to further understand the regulation of AT(1)R expression in neurons, we determined the role of sequential activation of the transcription factors nuclear factor-kappaB (NF-kappaB) and Ets-like protein 1 (Elk-1) in AT(1)R upregulation. We used CATH.a neurons as our neuronal cell model. Cells were treated with ANG II (100 nM) over a preset time course. Following ANG II activation, there was a temporal increase in the p65 subunit of NF-kappaB that was observed at 30 min, peaked at 1 h, and was sustained up to 24 h. There was a concomitant decrease of IkappaB and increased IkappaK expression. We also observed an increase in AT(1)R expression which followed the temporal increase of NF-kappaB. The activation of NF-kappaB was blocked by using the inhibitors parthenolide or p65 small interfering RNA (siRNA) which both led to a decrease in AT(1)R expression. The expression of Elk-1 was upregulated over a time period following ANG II activation and was decreased following NF-kappaB inhibition. p65-DNA binding was assessed using electrophoretic mobility shift assay, and it was shown that there was a time-dependent increased binding that was inhibited by means of parthenolide pretreatment or siRNA-mediated p65 gene silencing. Therefore, our results suggest a combined role for the transcription factors NF-kappaB and Elk-1 in the upregulation of AT(1)R in the CATH.a cell neuronal model. These data imply a positive feedback mechanism that may impact neuronal discharge sensitivity in response to ANG II.

Junb regulates arterial contraction capacity, cellular contractility, and motility via its target Myl9 in mice

Cellular contractility and, thus, the ability to alter cell shape are prerequisites for a number of important biological processes such as cytokinesis, movement, differentiation, and substrate adherence. The contractile capacity of vascular smooth muscle cells (VSMCs) is pivotal for the regulation of vascular tone and thus blood pressure and flow. Here, we report that conditional ablation of the transcriptional regulator Junb results in impaired arterial contractility in vivo and in vitro. This was exemplified by resistance of Junb-deficient mice to DOCA-salt-induced volume-dependent hypertension as well as by a decreased contractile capacity of isolated arteries. Detailed analyses of Junb-deficient VSMCs, mouse embryonic fibroblasts, and endothelial cells revealed a general failure in stress fiber formation and impaired cellular motility. Concomitantly, we identified myosin regulatory light chain 9 (Myl9), which is critically involved in actomyosin contractility and stress fiber assembly, as a Junb target. Consistent with these findings, reexpression of either Junb or Myl9 in Junb-deficient cells restored stress fiber formation, cellular motility, and contractile capacity. Our data establish a molecular link between the activator protein-1 transcription factor subunit Junb and actomyosin-based cellular motility as well as cellular and vascular contractility by governing Myl9 transcription.