Prognostic value of neurohumoral activation in patients with an acute myocardial infarction: effect of captopril

Sympathetic modulation as a goal of antihypertensive treatment: from drugs to devices

The present study aims to examine the effects of nonpharmacological, pharmacological and devices-based treatment on hypertension-related sympathetic overactivity. This will be done by analyzing the results of different published studies, in which sympathetic activity has been assessed via indirect or direct techniques. After examining the rationale for sympathomodulatory interventions in antihypertensive treatment, the study will discuss the methodological intrinsic limitations of the studies aimed at assessing different therapeutic interventions. The core of the study will be then focused on the effects of nonpharmacological (dietary restriction of sodium intake, physical exercise training, weight reduction), pharmacological (monotherapy, combination drug treatment, new drugs such as sodium glucose co-transport protein-2 inhibitors and angiotensin receptor neprilysin inhibitors), as well as devices-based interventions (renal sympathetic nerves ablation and carotid baroreceptor activation therapy) on the hypertension-related sympathetic overdrive. Finally, the areas worthy of future research as well as the debated issues in the field will be highlighted.

High blood pressure with elevated resting heart rate: a high risk "Sympathetic" clinical phenotype

Epidemiological studies have unequivocally shown that elevated heart rate values measured at rest have an adverse prognostic impact in the hypertensive patient, being associated with an increased risk of cardiovascular events and complications. In recent years new data have been collected on this issue, strengthening the clinical relevance of elevated heart rate as a specific hypertensive phenotype. The present paper will review old and new data on the prognostic importance of resting tachycardia in the hypertensive patient. It will also examine the role of the sympathetic nervous system in the development of this alteration as well as its therapeutic implications. The different approaches to dynamically assess heart rate values in the clinical setting will be finally discussed.

Prognostic Value of Novel Natriuretic Peptide Index After Percutaneous Coronary Intervention

BACKGROUND

The predictive value of both atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) is well known. This study evaluated the prognostic value of a novel natriuretic peptide index (NPI) combining ANP and BNP. Methods and Results: This study included 849 consecutive patients with coronary artery disease who underwent successful percutaneous coronary intervention (PCI). Patients were followed up clinically for up to 3 years or until the occurrence of major adverse cardiac events (MACE). The primary endpoint was a composite of all-cause death and non-fatal myocardial infarction. The NPI (pg/mL) was defined as √ANP×BNP. MACE occurred in 73 patients (8.6%) during the follow-up period. Receiver operating characteristic curve analysis showed the highest area under the curve for NPI (0.779) compared with ANP and BNP (0.773 and 0.755, respectively). A risk analysis of MACE occurrence adjusted for the multivariable model showed the highest hazard ratio (HR) for NPI (1.33; 95% confidence interval [CI] 1.18-1.51; P<0.001) compared with ANP and BNP (HR 1.25 [95% CI 1.13-1.39] and 1.30 [95% CI 1.13-1.49], respectively; P<0.001). The NPI was a significant independent predictor of MACE, among other clinical parameters, in the multivariable analysis.

CONCLUSIONS

Compared with ANP and BNP, the NPI was more effective in predicting future adverse events after PCI.

Involvement of Vasopressin in Tissue Hypoperfusion during Cardiogenic Shock Complicating Acute Myocardial Infarction in Rats

Acute heart failure (AHF) due to acute myocardial infarction (AMI) is likely to involve cardiogenic shock (CS), with neuro-hormonal activation. A relationship between AHF, CS and vasopressin response is suspected. This study aimed to investigate the implication of vasopressin on hemodynamic parameters and tissue perfusion at the early phase of CS complicating AMI. Experiments were performed on male Wistar rats submitted or not to left coronary artery ligation (AMI and Sham). Six groups were studied Sham and AMI treated or not with either a vasopressin antagonist SR-49059 (Sham-SR, AMI-SR) or agonist terlipressin (Sham-TLP, AMI-TLP). Animals were sacrificed one day after surgery (D₁) and after hemodynamic parameters determination. Vascular responses to vasopressin were evaluated, ex vivo, on aorta. AHF was defined by a left ventricular ejection fraction below 40%. CS was defined by AHF plus tissue hypoperfusion evidenced by elevated serum lactate level or low mesenteric oxygen saturation (SmO₂) at D₁. Mortality rates were 40% in AMI, 0% in AMI-SR and 33% in AMI-TLP. Immediately after surgery, a sharp decrease in SmO₂ was observed in all groups. At D₁, SmO₂ recovered in Sham and in SR-treated animals while it remained low in AMI and further decreased in TLP-treated groups. The incidence of CS among AHF animals was 72% in AMI or AMI-TLP while it was reduced to 25% in AMI-SR. Plasma copeptin level was increased by AMI. Maximal contractile response to vasopressin was decreased in AMI (32%) as in TLP- and SR- treated groups regardless of ligation. Increased vasopressin secretion occurring in the early phase of AMI may be responsible of mesenteric hypoperfusion resulting in tissue hypoxia. Treatment with a vasopressin antagonist enhanced mesenteric perfusion and improve survival. This could be an interesting therapeutic strategy to prevent progression to cardiogenic shock.

A Nomogram for Predicting Hospital Mortality in Intensive Care Unit Patients with Acute Myocardial Infarction

Background

This study aims to construct and validate an early-stage nomogram for predicting hospital mortality of ICU patients with acute myocardial infarction (AMI), to help clinicians determine the appropriate intervention.

Methods

The primary cohort of 2704 patients diagnosed with acute myocardial infarction in admission records from eICU-Collaborative Research Database (eICU-CRD) v2.0. Univariate logistic regression analysis and multivariate logistic regression analysis were enrolled for the construction of the predictive nomogram. Demographic factors, history of clinical cardiovascular disease, vital signs, the use of vasopressors, urine output, and serum variables in the first 24 hours were included in this analysis. The nomogram was evaluated by performance traits including Harrell's concordance index (C-index) and area under the receiver operating characteristic (AUC) analysis, calibration curve, and decision curve analysis (DCA). The nomogram was validated in a different cohort containing 1026 subjects collected from MIMIC-III Database v1.4. Finally, in order to compare the performance with other classic prediction models, AUC analysis, calibration curve, DCA and accuracy analysis (net reclassification improvement (NRI)) were conducted for three ICU scores in validated cohort.

Results

The nomogram revealed 14 predictors of the first 24 hours derived from univariate and multivariable analyses, including age, history of peripheral vascular disease, atrial fibrillation, cardiogenic shock and cardiac arrest, the use of norepinephrine, urine output, white blood cell (WBC), hemoglobin (Hb), red blood cell (RBC), red cell distribution width (RDW), glucose, bicarbonate and magnesium. The C-index of this nomogram was 0.834 (95% CI 0.812 to 0.856). Then, the result of AUC analysis, the DCA and calibration curve indicated that our nomogram was feasible for clinical prediction. The predictive ability and clinical use of the nomogram were verified in the validated cohort. The AUC analysis of ICU scores showed that the AUC of these score systems was ranged from 0.811 to 0.860 (the AUC of nomogram: 0.885). Moreover, our nomogram also showed a better performance in calibration curve and DCA NRI.

Conclusion

The study presents a prediction nomogram incorporating 14 variables that could help identify AMI patients admitted in ICU who might have a high risk of hospital mortality in the first hospitalized 24 hours. This nomogram showed a better performance than normal ICU score systems.

Pharmacotherapeutic principles of fluid management in heart failure

Introduction: Heart failure is a major public health concern that is expected to increase over the decades to come. Despite significant advances, fluid overload and congestion remain a major therapeutic challenge. Vascular congestion and neurohormonal activation are intricately linked and the goal of therapy fundamentally aims to reduce both.Areas covered: The authors briefly review a number of core concepts that elucidate the link between fluid overload and neuro-hormonal activation. This is followed by a review of heart-kidney interactions and the impact of diuresis in this setting. Following an in-depth review of currently available pharmacological agents, the rationale and evidence behind their use, the authors end with a brief note on novel agents/approaches to aid volume management in HF.Expert opinion: A number of non-pharmacological advances in the management of volume overload in heart failure, though promising - are associated with a number of shortcomings. Pharmacological therapy remains the cornerstone of volume management. A number of novel approaches, utilizing existing therapies as well as the emergence of new agents over the past decade bode well for the vulnerable HF population.

Copeptin concentration following cardiac surgery as a prognostic marker of postoperative acute kidney injury: a prospective cohort study

Background

Copeptin, the C-terminal portion of the arginine vasopressin precursor, is a novel candidate biomarker. This study investigated the prognostic value of copeptin levels following cardiac surgery for the occurrence of postoperative acute kidney injury.

Methods

We studied 23 patients who underwent cardiac surgery between January 2018 and December 2019. The primary endpoint was postoperative acute kidney injury onset. Copeptin levels were measured before, right after, and daily for 7 days. The patients were divided into two groups according to the copeptin levels: low (values <43.7 pmol/L) and high (values ≥43.7 pmol/L). Correlations between copeptin levels and variables, such as central venous pressure, were assessed by bivariate analysis.

Results

The high copeptin group exhibited significantly higher levels of arginine vasopressin and cortisol following surgery, compared to those of the low copeptin group. The copeptin concentration following surgery was correlated to central venous pressure (P=0.03) and norepinephrine administered dose (P=0.008). Also, the copeptin levels right after surgery robustly predicted the onset of postoperative acute kidney injury (area under the receiver operating characteristic curve of 0.83, P=0.004).

Conclusions

Elevated copeptin levels in patients following cardiac surgery predicted postoperative acute kidney injury development. Therefore, the copeptin concentration after surgery could represent a promising clinical biomarker of the postoperative cardiac outcome.

Add-on aliskiren treatment can decrease blood pressure but requires attention to risks of renal impairment and hyperkalemia Chikushi Anti-Hypertension Trial-Rasilez® (CHAT-Ras)

BACKGROUND

Renin is the starting point of the renin angiotensin (RA) system cycle. Aliskiren (AL), which is a direct renin inhibitor, suppressed the entire RA cycle. In the present study, the efficacy of add-on of AL treatment in patients with essential hypertension (HT) was investigated.

METHODS

This study was a multi-center, open-label, prospective, observational study. Study subjects were patients with essential HT and poor blood pressure (BP) control, who had received calcium channel blocker monotherapy or angiotensin II receptor blocker monotherapy or had not received any BP lowering drugs. Following add-on of AL for 12 months, BP and additional laboratory findings were analyzed.

RESULTS

A total of 150 subjects were enrolled. There were 50 dropout subjects including discontinuation. Dropouts were the highest in the ARB combination therapy group at 9 subjects due to adverse events, and 3 of them were due to hyperkalemia. A significantly higher number of patients with chronic kidney disease (CKD) dropped out compared to patients without CKD (φ = 0.166, p < .05). BP before add-on of AL was 155/88 mmHg. After add-on of AL, BP was significantly improved and this lowering was sustained for 3 months (136/78 mmHg, p < .001), 6 months (136/77 mmHg, p < .001) and 12 months (134/78 mmHg, p < .001). In contrast, add-on of AL increased the potassium level and decreased the estimated glomerular filtration rate.

CONCLUSION

While add-on AL treatment achieved a favorable and sustained decrease of BP in this study, caution is necessary with regard to elevation of potassium levels and renal impairment.

Functional coupling between NMDA receptors and SK channels in rat hypothalamic magnocellular neurons: altered mechanisms during heart failure

KEY POINTS

Glutamatergic NMDA receptors (NMDARs) and small conductance Ca²⁺ -activated K⁺ (SK) channels are critical synaptic and intrinsic mechanisms, respectively, that regulate the activity of hypothalamic magnocellular neurosecretory neurons (MNNs). In this work, we investigated whether NMDARs and SK channels in MNNs are functionally coupled, and whether an altered coupling may contribute to exacerbated neuronal activity in this condition. We report that NMDARs and SK channels form a functional Ca²⁺ -dependent negative feedback loop that restrains the excitatory effect on membrane potential and firing activity evoked by NMDAR activation. The negative feedback loop between NMDARs and SK channels was blunted or absent in MNNs of heart failure (HF) rats. These results help us better understand how synaptic and intrinsic mechanisms regulate hypothalamic neuronal activity, as well as how changes in the interaction among these disparate mechanisms contribute to altered neuronal activity during prevalent neurogenic cardiovascular diseases.

ABSTRACT

Glutamatergic NMDA receptors (NMDARs) and small conductance Ca²⁺ -activated K⁺ (SK) channels are critical synaptic and intrinsic mechanisms, respectively, that regulate the activity of hypothalamic magnocellular neurosecretory neurons (MNNs), both under physiological and pathological states, such as lactation and heart failure (HF). However, whether NMDARs and SK channels in MNNs are functionally coupled, and whether changes in this coupling contribute to exacerbated neuronal activity during HF is at present unknown. In the present study, we addressed these questions using patch-clamp electrophysiology and confocal Ca²⁺ imaging in a rat model of ischaemic HF. We found that in MNNs of sham rats, blockade of SK channels with apamin (200 nM) significantly increased the magnitude of an NMDAR-evoked current (I_NMDA ). We also observed that blockade of SK channels potentiated NMDAR-evoked firing, and abolished spike frequency adaptation in MNNs from sham, but not HF rats. Importantly, a larger I_NMDA -ΔCa²⁺ response was observed under basal conditions in HF compared to sham rats. Finally, we found that dialysing recorded cells with the Ca²⁺ chelator BAPTA (10 mM) increased the magnitude of I_NMDA in MNNs from both sham and HF rats, and occluded the effects of apamin in the former. Together our studies demonstrate that in MNNs, NMDARs and SK channels are functionally coupled, forming a local negative feedback loop that restrains the excitatory effect evoked by NMDAR activation. Moreover, our studies also support a blunted NMDAR-SK channel coupling in MNNs of HF rats, establishing it as a pathophysiological mechanism contributing to exacerbated hypothalamic neuronal activity during this prevalent neurogenic cardiovascular disease.

Antidiuretic Hormone and Serum Osmolarity Physiology and Related Outcomes: What Is Old, What Is New, and What Is Unknown?

CONTEXT

Although the physiology of sodium, water, and arginine vasopressin (AVP), also known as antidiuretic hormone, has long been known, accumulating data suggest that this system operates as a more complex network than previously thought.

EVIDENCE ACQUISITION

English-language basic science and clinical studies of AVP and osmolarity on the development of kidney and cardiovascular disease and overall outcomes.

EVIDENCE SYNTHESIS

Apart from osmoreceptors and hypovolemia, AVP secretion is modified by novel factors such as tongue acid-sensing taste receptor cells and brain median preoptic nucleus neurons. Moreover, pharyngeal, esophageal, and/or gastric sensors and gut microbiota modulate AVP secretion. Evidence is accumulating that increased osmolarity, AVP, copeptin, and dehydration are all associated with worse outcomes in chronic disease states such as chronic kidney disease (CKD), diabetes, and heart failure. On the basis of these pathophysiological relationships, an AVP receptor 2 blocker is now licensed for CKD related to polycystic kidney disease.

CONCLUSION

From a therapeutic perspective, fluid intake may be associated with increased AVP secretion if it is driven by loss of urine concentration capacity or with suppressed AVP if it is driven by voluntary fluid intake. In the current review, we summarize the literature on the relationship between elevated osmolarity, AVP, copeptin, and dehydration with renal and cardiovascular outcomes and underlying classical and novel pathophysiologic pathways. We also review recent unexpected and contrasting findings regarding AVP physiology in an attempt to explain and understand some of these relationships.

Cardiorenal Syndrome: Pathophysiology

Cardiorenal syndrome commonly refers to the collective dysfunction of heart and kidney resulting in a cascade of feedback mechanism causing damage to both the organs and is associated with adverse clinical outcomes. The pathophysiology of cardiorenal syndrome is complex, multifactorial, and dynamic. Improving the understanding of disease mechanisms will aid in developing targeted pharmacologic and nonpharmacologic therapies for the management of this syndrome. This article discusses the various mechanisms involved in the pathophysiology of the cardiorenal syndrome.

Utility of copeptin for predicting long-term clinical outcomes in patients with heart failure

BACKGROUND

Copeptin, a surrogate marker of pro-arginine vasopressin, is expected to be a marker in cardiovascular diseases. Its utility for predicting long-term clinical outcomes in heart failure (HF), however, has not been adequately evaluated in daily clinical practice in Japan.

METHODS

To assess the relationship of serum copeptin at admission with long-term clinical outcomes, we evaluated serum copeptin at admission in consecutive 107 patients hospitalized for HF between April 2011 and July 2012. The primary outcome measure was defined as a composite of all-cause death and re-admission for HF (all-cause death/HF).

RESULTS

In this study population, median serum copeptin at admission was 15.5 (6.7-32.0)pmol/L. As compared with the low-copeptin group (<18pmol/L, N=60), the high-copeptin group (≥18pmol/L, N=47) included more male patients and those with prior myocardial infarction, prior HF, low left ventricular ejection fraction, and chronic kidney disease. During median 4.5 (1.0-5.5) years of clinical follow-up, the cumulative incidence of all-cause death/HF was significantly higher in the high-copeptin than in the low-copeptin group (63.4% versus 33.0% at 1 year, and 85.2% versus 77.2% at 5 years, log-rank p=0.03). After adjusting for confounders, high-copeptin was still an independent predictor for all-cause death/HF [hazard ratio (95% confidence interval): 1.77 (1.04-3.01), p=0.03].

CONCLUSION

Copeptin was suggested as a useful marker for predicting long-term clinical outcomes in patients with HF.

A reduction in SK channels contributes to increased activity of hypothalamic magnocellular neurons during heart failure

KEY POINTS

Small conductance Ca2+ -activated K+ (SK) channels play an important role in regulating the excitability of magnocellular neurosecretory cells (MNCs). Although an increased SK channel function contributes to adaptive physiological responses, it remains unknown whether changes in SK channel function/expression contribute to exacerbated MNC activity under disease conditions. We show that the input-output function of MNCs in heart failure (HF) rats is enhanced. Moreover, the SK channel blocker apamin enhanced the input-output function in sham, although not in HF rats. We found that both the after-hyperpolarizing potential magnitude and the underlying apamin-sensitive IAHP are blunted in MNCs from HF rats. The magnitude of spike-induced increases in intracellular Ca2+ levels was not affected in MNCs of HF rats. We found a diminished expression of SK2/SK3 channel subunit mRNA expression in the supraoptic nucleus of HF rats. Our studies suggest that a reduction in SK channel expression, but not changes in Ca2+ -mediated activation of SK channels, contributes to exacerbated MNC activity in HF rats.

ABSTRACT

Small conductance Ca2+ -activated K+ channels (SK) play an important role in regulating the activity of magnocellular neurosecretory cells (MNCs) and hormone release from the posterior pituitary. Moreover, enhanced SK activity contributes to the adaptive responses of MNCs to physiological challenge, such as lactation. Nevertheless, whether changes in SK function/expression contribute to exacerbated MNC activity during diseases such as heart failure (HF) remains unknown. In the present study, we used a combination of patch clamp electrophysiology, confocal Ca2+ imaging and molecular biology in a rat model of ischaemic HF. We found that the input-output function of MNCs was enhanced in HF compared to sham rats. Moreover, although the SK blocker apamin (200 nm) strengthened the input-output function in sham rats, it failed to have an effect in HF rats. The magnitude of the after-hyperpolarizing potential (AHP) following a train of spikes and the underlying apamin-sensitive IAHP were blunted in MNCs from HF rats. However, spike-induced increases in intracellular Ca2+ were not affected in the MNCs of HF rats. Real-time PCR measurements of SK channel subunits mRNA in supraoptic nucleus punches revealed a diminished expression of SK2/SK3 subunits in HF compared to sham rats. Together, our studies demonstrate that MNCs from HF rats exhibit increased membrane excitability and an enhanced input-output function, and also that a reduction in SK channel-mediated, apamin-sensitive AHP is a critical contributing mechanism. Moreover, our results suggest that the reduced AHP is related to a down-regulation of SK2/SK3 channel subunit expression but not the result of a blunted activity-dependent intracellular Ca2+ increase following a burst of action potentials.

Impact of Morning Onset on the Incidence of Recurrent Acute Coronary Syndrome and Progression of Coronary Atherosclerosis in Acute Myocardial Infarction

BACKGROUND

The relationship between time of onset of acute myocardial infarction (MI) and long-term clinical outcome has not been completely understood. We hypothesized that morning onset acute MI may be associated with adverse cardiac events.Methods and Results:This study involved 663 patients who underwent primary percutaneous coronary intervention (PCI). The main outcome measures were cardiac death, recurrent acute coronary syndrome (ACS), and re-hospitalization for heart failure. Major adverse cardiac events (MACE) were defined as a composite of individual adverse outcomes. Morning onset acute MI occurred in 212 patients (32.0%); they had higher rates of recurrent ACS (13% vs. 8%, P=0.03) and MACE (21% vs. 14%, P=0.012) than the patients with other times of onset. The PCI rate for progressive lesions was also higher than for patients with other times of onset (23% vs. 14%, P=0.013). On multivariate Cox regression analysis, morning onset was an independent predictor of recurrent ACS, MACE, and PCI for progressive lesions, with adjusted hazard ratios of 1.34 (95% CI: 1.06-2.92, P=0.030), 1.51 (95% CI: 1.02-2.23, P=0.038), and 1.58 (95% CI: 1.03-2.42, P=0.037), respectively.

CONCLUSIONS

Morning onset may be associated with increased risk of recurrent ACS and coronary atherosclerosis progression.

Aldosterone Does Not Predict Cardiovascular Events Following Acute Coronary Syndrome in Patients Initially Without Heart Failure

Background

Aldosterone may have adverse effects in the myocardium and vasculature. Treatment with an aldosterone antagonist reduces cardiovascular risk in patients with acute myocardial infarction complicated by heart failure (HF) and left ventricular systolic dysfunction. However, most patients with acute coronary syndrome do not have advanced HF. Among such patients, it is unknown whether aldosterone predicts cardiovascular risk.

Methods and Results

To address this question, we examined data from the dal‐OUTCOMES trial that compared the cholesteryl ester transfer protein inhibitor dalcetrapib with placebo, beginning 4 to 12 weeks after an index acute coronary syndrome. Patients with New York Heart Association class II (with LVEF <40%), III, or IV HF were excluded. Aldosterone was measured at randomization in 4073 patients. The primary outcome was a composite of coronary heart disease death, nonfatal myocardial infarction, stroke, hospitalization for unstable angina, or resuscitated cardiac arrest. Hospitalization for HF was a secondary endpoint. Over a median follow‐up of 37 months, the primary outcome occurred in 366 patients (9.0%), and hospitalization for HF occurred in 72 patients (1.8%). There was no association between aldosterone and either the time to first occurrence of a primary outcome (hazard ratio for doubling of aldosterone 0.92, 95% confidence interval 0.78‐1.09, P=0.34) or hospitalization for HF (hazard ratio 1.38, 95% CI 0.96‐1.99, P=0.08) in Cox regression models adjusted for covariates.

Conclusions

In patients with recent acute coronary syndrome but without advanced HF, aldosterone does not predict major cardiovascular events.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00658515.

Steroidal and Novel Non-steroidal Mineralocorticoid Receptor Antagonists in Heart Failure and Cardiorenal Diseases: Comparison at Bench and Bedside

Characterization of mice with cell-specific deletion or overexpression of the mineralocorticoid receptor (MR) shed a new light on its role in health and disease. Pathophysiological MR activation contributes to a plethora of deleterious molecular mechanisms in the development of cardiorenal diseases like chronic kidney disease (CKD) and heart failure (HF). Accordingly, the available steroidal MR antagonists (MRAs) spironolactone (first generation MRA) and eplerenone (second generation MRA) have been shown to be effective in reducing cardiovascular (CV) mortality and morbidity in patients with chronic HF and a reduced left ventricular ejection fraction (HFrEF). However, they remain underutilized, in large part owing to the risk inducing severe adverse events including hyperkalemia and worsening of kidney function, particularly when given on top of inhibitors of the renin angiotensin system (RAS) to patients with concomitant kidney dysfunction. Novel, potent, and selective non-steroidal MRAs (third generation) were identified in drug discovery campaigns and a few entered clinical development recently. One of these is finerenone with different physicochemical, pharmacokinetics, and pharmacological properties in comparison with the steroidal MRAs. Available data from five clinical phase II trials with finerenone in more than 2,000 patients with HF and additional CKD and/or diabetes as well as in patients with diabetic kidney disease demonstrated that neither hyperkalemia nor reductions in kidney function were limiting factors to its use. Moreover, finerenone demonstrated a nominally improved outcome compared to eplerenone in a phase IIb trial with 1,066 patients with HFrEF and concomitant type 2 diabetes mellitus (T2DM) and/or CKD.

Elevation of arginine vasopressin levels following loop diuretic therapy as a prognostic indicator in heart failure

Objective

To investigate the association between arginine vasopressin (AVP) levels and loop diuretic (LD) therapy in patients with heart failure and to determine if AVP levels are a prognostic indicator of treatment failure.

Methods

Patients with stable heart failure and reduced (< 40%) left ventricular ejection fraction (LVEF) were divided into those treated with (LD) or without LD (NLD). The LD group was separated into subgroups of high (> 6.5 pg/dl) and low (≤ 6.5 pg/dl) AVP levels. The clinical and biochemical characteristics of the two groups were compared and the prognostic value of AVP levels in heart failure evaluated.

Results

Of the 63 patients enrolled into the study, 41 (65.1%) were in the LD group and 22 (34.9%) were in the NLD group. Despite no differences between groups in LVEF, creatinine clearance, or brain natriuretic peptide, the LD group had significantly higher AVP levels compared with the NLD group. A Cox proportional-hazards model showed that AVP was an independent predictor of adverse events. In addition, the elevation in AVP in the LD group was inversely correlated with an increase in free water clearance but not serum osmolality and was related to poor outcome.

Conclusions

Elevated AVP levels in patients with heart failure who received LD therapy were associated with a poor prognosis. Loop diuretics may induce non-osmolar AVP release, which can worsen heart failure.

Effects of Long-term Blockade of Vasopressin Receptor Types 1a and 2 on Cardiac and Renal Damage in a Rat Model of Hypertensive Heart Failure

The effects of chronic blockade of vasopressin type 1a receptors (V1aR) and the additive effects of a type 2 receptor (V2R) antagonist on the treatment of hypertension-induced heart failure and renal injury remain to be unknown. In this study, Dahl salt-sensitive hypertensive rats were chronically treated with a vehicle (CONT), a V1aR antagonist (OPC21268; OPC), a V2R antagonist (tolvaptan; TOLV), or a combination of OPC21268 and tolvaptan (OPC/TOLV) from the pre-hypertrophic stage (6 weeks). No treatment altered blood pressure during the study. Significant improvements were seen in median survival for the OPC and TOLV, and the OPC/TOLV showed a further improvement in Kaplan-Meier analysis. Echocardiography showed suppressed left ventricular hypertrophy in the OPC and OPC/TOLV at 11 weeks with improved function in all treatment groups by 17 weeks. In all treatment groups, improvements were seen in the following: myocardial histological changes, creatinine clearance, urinary albumin excretion, and renal histopathologic damage. Also, key mRNA levels were suppressed (eg, endothelin-1 and collagen). In conclusion, chronic V1aR blockade ameliorated disease progression in this rat model, with additive benefits from the combination of V1aR and V2R antagonists. It was associated with protection of both myocardial and renal damage, independent of blood pressure.

Plasma renin activity and risk of cardiovascular and mortality outcomes among individuals with elevated and nonelevated blood pressure

Background

We sought to evaluate plasma renin activity (PRA) levels and risk of mortality and cardiovascular events among individuals with elevated blood pressure [systolic blood pressure (SBP) ≥ 140 mmHg] and those with controlled blood pressure (SBP < 140 mmHg) in a large diverse population.

Methods

A retrospective cohort study between January 1, 2007, and December 31, 2013, among adults (≥ 18 years) within an integrated health system was conducted. Subjects were categorized by SBP into 2 groups: SBP < 140 mmHg and SBP ≥ 140 mmHg and then further categorized into population-based PRA tertiles within each SBP group. Cox proportional hazard modeling was used to estimate hazard ratios for cardiovascular and mortality outcomes among tertiles of PRA levels.

Results

Among 6,331 subjects, 32.6% had SBP ≥ 140 mmHg. Multivariable hazard ratios and 95% confidence interval for PRA tertiles T2 and T3 compared to T1 in subjects with SBP ≥ 140 mmHg were 1.42 (0.99–2.03) and 1.61 (1.12–2.33) for ischemic heart events; 1.40 (0.93–2.10) and 2.23 (1.53–3.27) for congestive heart failure; 1.10 (0.73–1.68) and 1.06 (0.68–1.66) for cerebrovascular accident; 1.23 (0.94–1.59) and 1.43 (1.10–1.86) for combined cardiovascular events; and 1.39 (0.97–1.99) and 1.35 (0.92–1.97) for all-cause mortality, respectively. Among the SBP < 140 mmHg group, there was no relationship between PRA levels and outcomes.

Conclusion

Higher PRA levels demonstrated increased risk for ischemic heart events and congestive heart failure and a trend toward higher mortality among individuals with SBP ≥ 140 mmHg but not among those with SBP < 140 mmHg.

A Functional Coupling Between Carbon Monoxide and Nitric Oxide Contributes to Increased Vasopressin Neuronal Activity in Heart Failure rats

Despite the pathophysiological importance of neurohumoral activation in patients with heart failure (HF), the precise underlying mechanisms contributing to elevated vasopressin (VP) activation in HF remains unknown. Carbon monoxide (CO) is a gaseous neurotransmitter in the central nervous system that stimulates VP neuronal firing activity. Recently, we showed that the excitatory effect of CO on VP neurons in the hypothalamic paraventricular nucleus (PVN) was mediated by inhibition of nitric oxide (NO). Given that previous studies showed that VP neuronal activity is enhanced, whereas NO inhibitory signaling is blunted in HF rats, we tested whether an enhanced endogenous CO availability within the PVN contributes to elevated VP neuronal activity and blunted NO signaling in HF rats. We found that both haeme-oxygenase 1 (the CO-synthesizing enzyme) protein and mRNA expression levels were enhanced in the PVN of HF compared with sham rats (∼18% and ∼38%, respectively). We report that in sham rats, bath application of a CO donor (tricarbonyldichlororuthenium dimer) increased the firing activity of identified PVN VP neurons (P < .05), whereas inhibition of endogenous CO production (Tin-protoporphyrin IX [SnPP]) failed to affect neuronal activity. In HF rats, however, SnPP decreased VP activity (P < .05), an effect that was occluded by previous NO synathase blockade NG-nitro-larginine methyl ester. Finally, we found that SnPP increased the mean frequency of γ-aminobutyric acid inhibitory postsynaptic currents in VP neurons in HF (P < .05) but not sham rats. Our results support an enhanced endogenous CO excitatory signaling in VP neurons, which likely contributes to blunted NO and γ-aminobutyric acid inhibitory function in HF rats.

Effects of angiotensin-(1-7) on the proliferation and collagen synthesis of arginine vasopressin-stimulated rat cardiac fibroblasts: role of mas receptor-calcineurin-NF-κB signaling pathway

: Interstitial fibrosis is a common pathological change in various heart diseases, especially cardiac hypertrophy. Arginine vasopressin (AVP), one of the hallmarks of heart failure, exhibits a profibrotic effect by promoting the proliferation and differentiation of cardiac fibroblasts (CFs). In contrast, angiotensin-(1-7) [Ang-(1-7)] was reported to be beneficial for cardiac remodeling by its antifibrotic effect. To evaluate the effect of Ang-(1-7) on AVP-stimulated CFs and the subsequent signaling molecules involved, CFs isolated from neonatal rat hearts were incubated with AVP and treated with or without Ang-(1-7). Cell proliferation, cell cycle, collagen production, and related cellular signaling molecules were then assessed. The results showed that Ang-(1-7) dose-dependently inhibited cell proliferation and collagen production in AVP-stimulated CFs. In addition, Ang-(1-7) also significantly suppressed calcineurin activity in a dose-dependent manner in AVP-stimulated CFs, which was associated with reduced collagen production. Accordingly, the nuclear translocation and transcriptional activity of nuclear factor-kappa B (NF-κB), downstream signal of calcineurin, were also notably restrained by Ang-(1-7) in AVP-stimulated CFs. Furthermore, the inhibitory effect of Ang-(1-7) on AVP-activated calcineurin-NF-κB signaling was completely reversed by the Mas receptor antagonist A-799. These findings suggest that Ang-(1-7) exerts an antifibrotic effect by inhibiting AVP-stimulated CF proliferation and collagen synthesis by inactivating Mas receptor-calcineurin-NF-κB signaling pathway.

Neuroendocrine-autonomic integration in the paraventricular nucleus: novel roles for dendritically released neuropeptides

Communication between pairs of neurones in the central nervous system typically involves classical 'hard-wired' synaptic transmission, characterised by high temporal and spatial precision. Over the last two decades, however, knowledge regarding the repertoire of communication modalities used in the brain has notably expanded to include less conventional forms, characterised by a diffuse and less temporally precise transfer of information. These forms are best suited to mediate communication among entire neuronal populations, now recognised to be a fundamental process in the brain for the generation of complex behaviours. In response to an osmotic stressor, the hypothalamic paraventricular nucleus (PVN) generates a multimodal homeostatic response that involves orchestrated neuroendocrine (i.e. systemic release of vasopressin) and autonomic (i.e. sympathetic outflow to the kidneys) components. The precise mechanisms that underlie interpopulation cross-talk between these two distinct neuronal populations, however, remain largely unknown. The present review summarises and discusses a series of recent studies that have identified the dendritic release of neuropeptides as a novel interpopulation signalling modality in the PVN. A current working model is described in which it is proposed that the activity-dependent dendritic release of vasopressin from neurosecretory neurones in the PVN acts in a diffusible manner to increase the activity of distant presympathetic neurones, resulting in an integrated sympathoexcitatory population response, particularly within the context of a hyperosmotic challenge. The cellular mechanism underlying this novel form of intercellular communication, as well as its physiological and pathophysiological implications, is discussed.

Impact of initial 24-h urine output on short-term outcomes in patients with ST-segment elevation myocardial infarction admitted without cardiogenic shock and renal dysfunction

OBJECTIVES

Our study aims to evaluate the prognostic value of initial 24-h urine output (UO) in patients with ST-segment elevation myocardial infarction (STEMI) admitted without cardiogenic shock and renal dysfunction, and to determine the additional risk stratification offered by adding initial 24-h UO to TIMI risk score (TRS).

METHODS

Data from 7078 consecutive STEMI patients in a multi-center registry were retrospectively analyzed. Patients were divided into 4 groups according to initial 24-h UO quartiles. The primary endpoints were 7- and 30-day all-cause mortality.

RESULTS

Patients in the lowest UO quartile (≤1020 mL) had significantly higher 7- and 30-day all-cause mortality rates, cardiogenic shock, and major adverse cardiovascular events (MACE) than those in other groups (all P<0.05). After multivariate adjustment, initial 24-h UO≤1020 mL was independently associated with an increased risk in 7-day all-cause mortality (HR=4.649, 95%CI 3.348-6.455) and 30-day all-cause mortality (HR=3.775, 95%CI 2.891-4.931) as well as 7-day MACE (HR=1.845, 95%CI 1.563-2.179) and 30-day MACE (HR=1.818, 95%CI 1.553-2.127). Initial 24-h UO provided additional risk stratification across all TRS groups and improved the discriminatory ability of TRS with respect to 7-day all-cause mortality (c-statistic from 0.704 to 0.764) and 30-day all-cause mortality (c-statistic from 0.706 to 0.743).

CONCLUSION

Reduced initial 24-h UO (≤1020 mL) was associated with an increased risk in 7- and 30-day all-cause mortality and MACE in STEMI patients admitted without cardiogenic shock and renal dysfunction. The combination of initial 24-h UO and TRS improved short-term outcome prediction when compared to TRS alone, particularly in patients with initial 24-h UO≤1020 mL.

Plasma renin activity is a strong and independent prognostic indicator in patients with acute decompensated heart failure treated with renin-angiotensin system inhibitors

BACKGROUND

The renin-angiotensin system (RAS) is activated in heart failure (HF) as a compensatory mechanism, being related to cardiac remodeling and poor prognosis. Although RAS inhibitors are used as first-line drugs for HF, plasma renin activity (PRA) is upregulated by RAS inhibitors via a negative feedback mechanism. The clinical significance of PRA during RAS inhibitor therapy is poorly understood in acute decompensated HF (ADHF). Therefore we examined the impact of PRA in HF patients already receiving RAS inhibitors.

METHODS AND RESULTS

Of 611 consecutive patients with ADHF and emergency admission to hospital, we studied the impact of PRA on the prognosis of ADHF in 293 patients already receiving RAS inhibitors before admission. The patients were divided into 2 groups according to median PRA (≥ vs. <3.4 ng·ml(-1)·h(-1)). During a mean follow-up of 29.0 months, there were 124 deaths from all causes. Kaplan-Meier analysis showed that all-cause and cardiovascular mortality were significantly higher in patients with high PRA than low PRA (log-rank P=0.0002 and P<0.0001, respectively). Log PRA was an independent predictor of all-cause and cardiovascular death (HR, 1.194; 95% CI: 1.378-2.678, P<0.0001; and HR, 2.559; 95% CI: 1.610-4.144, P<0.0001, respectively).

CONCLUSIONS

PRA was associated with an increased risk of all-cause and cardiovascular mortality in ADHF patients already receiving RAS inhibitors, suggesting that PRA would be a useful biomarker during ADHF treatment.

Biomarkers of activation of renin-angiotensin-aldosterone system in heart failure: how useful, how feasible?

Renin-angiotensin-aldosterone system (RAAS), participated by kidney, liver, vascular endothelium, and adrenal cortex, and counter-regulated by cardiac endocrine function, is a complex endocrine system regulating systemic functions, such as body salt and water homeostasis and vasomotion, in order to allow the accomplishment of physiological tasks, such as orthostasis, physical and emotional stimuli, and to react towards the hemorrhagic insult, in tight conjunction with other neurohormonal axes, namely the sympathetic nervous system, the endothelin and vasopressin systems. The systemic as well as the tissue RAAS are also dedicated to promote tissue remodeling, particularly relevant after damage, when chronic activation may configure as a maladaptive response, leading to fibrosis, hypertrophy and apoptosis, and organ dysfunction. RAAS activation is a fingerprint of systemic arterial hypertension, kidney dysfunction, vascular atherosclerotic disease, and is definitely an hallmark of heart failure, which rapidly shifts from organ disease to a disorder of neurohormonal regulatory systems. Chronic RAAS activation is an indirect or direct target of most effective pharmacological treatments in heart failure, such as beta-blockers, inhibitors of angiotensin converting enzyme, angiotensin receptor blockers, direct renin inhibitors, and mineralocorticoid receptor blockers. Biomarkers of RAAS activation are available, with different feasibility and accuracy, such as plasma renin activity, renin, angiotensin II, and aldosterone, which all accompany the increasing clinical severity of heart failure disease, and are well recognized prognostic factors, even in patients with optimal therapy. Polymorphisms influencing the expression and activity of RAAS pathways have been recognized as clinically relevant biomarkers, likely influencing either the individual clinical phenotype, or the response to drugs. This solid, growing evidence strongly suggests the rationale for the use of biomarkers of the RAAS activation, as a guide to tailor individual therapy in the current practice, and their implementation as a rule-in marker for future trials on novel drugs in the heart failure setting.

Aldosterone augments Na+-induced reduction of cardiac norepinephrine reuptake

Impairment of the cardiac norepinephrine (NE) reuptake by the neuronal NE transporter contributes to enhanced cardiac NE net release in congestive heart failure. Elevated plasma levels of aldosterone (AL) promote sympathetic overstimulation in failing hearts by unclear mechanisms. Our aim was to evaluate if elevated AL and/or alterations in Na(+) intake regulate cardiac NE reuptake. To test the effects of AL and Na(+) on cardiac NE reuptake, Wistar rats were fed a normal-salt (NS) diet (0.2% NaCl), a low-salt (LS) diet (0.015% NaCl), or a high-salt (HS) diet (8% NaCl). Another group of animals received AL infusion alone (0.75 μg/h) or AL infusion plus HS diet. Specific cardiac [(3)H]NE uptake via the NE transporter in a Langendorff preparation and AL plasma levels were measured at different time points between 5 and 42 days of treatment. To compare these findings from healthy animals with a disease model, Dahl salt-sensitive rats were investigated as a model of congestive heart failure with endogenously elevated AL. In summary, neither exogenous nor endogenous elevations of AL alone were sufficient to reduce cardiac NE reuptake. Only the HS diet induced a reduction of NE reuptake by 26%; additional infusion of AL augmented this effect to a further reduction of NE reuptake by 36%. In concordance, Dahl salt-sensitive rats treated with a HS diet displayed elevated AL and a marked reduction of NE reuptake. We conclude that exogenous or endogenous AL elevations alone do not reduce cardiac NE reuptake, but AL serves as an additional factor that negatively regulates cardiac NE reuptake in concert with HS intake.

Can the difference in serum concentration of urea and cystatin C be used in diagnosis and prognosis of heart failure?

Changes in renal function are an important diagnostic and prognostic indicator in patients with heart failure (HF). They are caused by decreased renal perfusion and consequently decreased glomerular filtration rate (GFR), or by the effect of increased neurohormonal activity (sympathetic nervous system [SNS], rennin-angiotensin-aldosterone system [RAAS] and arginine vasopressin [AVP]). However, the increase of serum concentration of urea, creatinine and other metabolites is not specific for HF. Therefore, it is not possible to distinguish HF from renal diseases solely based on the increase of their concentration, since the increase of their concentration caused by the decrease of GFR cannot be differentiated from the increase due to neurohormonal activity. Urea and cystatin C (Cys C) have different mechanisms of renal elimination, so it can be assumed that in HF their concentrations will not be increased proportionally, what can be used for diagnostic and prognostic purposes. After glomerular filtration Cy C undergoes proximal tubular reabsorption and breakdown, without returning to the blood flow. Since it is not secreted, its serum concentration depends only on GFR. In contrast to Cys C, urea is filtered in glomerulus and subsequently reabsorbed in proximal tubules and collecting duct. Reabsorption of urea is modified by effects of SNS, RAAS and AVP. Therefore its serum concentration depends upon GFR and neurohormonal effect on the tubular function. Since the increase of serum concentration of Cys C is caused only by the effect of the decreased renal perfusion on GFR, while the increase of urea is a result from both decreased GFR and tubular effects of increased neurohormonal activity, the paper hypothesis is that in HF the increase of urea will be significantly higher than the increase of serum Cys C, while in the patients with renal diseases their increase would be mostly proportional. It can be assumed that the disproportion between the increase of Cys C and urea would indicate an increased neurohormonal activity in patients with HF and correlate with its activity. If this hypothesis is proved correct, this parameter could be used in HF diagnosis and risk stratification of such patients.

Long-term sympathoinhibitory effects of surgically induced weight loss in severe obese patients

Weight loss improves insulin sensitivity and exerts sympathomodulatory effects. No data, however, are available on the effects of the weight loss induced by vertical sleeve gastrectomy on sympathetic neural drive, insulin sensitivity, and their reciprocal cross talks. In 10 severe obese hypertensives (age, 54.0±2.3 years [mean±SEM]), we measured sphygmomanometric blood pressure, heart rate, body mass index, homeostatic model assessment index, plasma leptin, muscle sympathetic nerve traffic (microneurography), and baroreflex sensitivity (vasoactive drug technique). Measurements were performed 2 to 3 days before surgery and repeated 6 and 12 months after the procedure. Ten matched hypertensive obeses not undergoing gastrectomy served as controls. Six months after bariatric surgery, a significant (P<0.05) reduction in body mass index (-9.1±1.4 kg/m(2)), sphygmomanometric systolic blood pressure (-10.2±4.5 mm Hg), heart rate (-11.0±2.4 bpm), homeostatic model assessment index (-3-3±1.3 AU), plasma leptin (-53.6±8.8 μg/L), and muscle sympathetic nerve traffic (-15.0±3.4 bursts/100 heart beats) was observed. The weight loss, the plasma leptin reduction, and the sympathetic inhibition were maintained after 12 months, whereas homeostatic model assessment index showed a tendency to return toward presurgery values. A significant improvement in baroreflex control of sympathetic nerve traffic was observed both 6 (+32.1%; P<0.05) and 12 months (+60.7%; P<0.01) after gastrectomy. No significant changes in the above-mentioned variables were detected in the control group. These data provide evidence that massive weight loss induced by sleeve gastrectomy triggers profound sympathoinhibitory effects, associated with a stable and significant reduction in plasma leptin levels, whereas the improvement in insulin sensitivity was attenuated with time and unrelated to the sympathoinhibition.

Role of the sympathetic nervous system in hypertension and hypertension-related cardiovascular disease

A number of cardiovascular disease have been shown to be characterized by a marked increase in sympathetic drive to the heart and the peripheral circulation. This is the case for essential hypertension, congestive heart failure, cardiac arrhythmias, obesity, metabolic syndrome, obstructive sleep apnea, and chronic renal disease. This review focuses on the most recent findings documenting the role of sympathetic neural factors in the development and progression of the hypertensive state as well as in the pathogenesis of hypertension-related target organ damage. It also reviews the role of sympathetic neural factors in the development of cardiovascular diseases not necessarily strictly related to the hypertensive state, such as congestive heart failure, cardiac arrhythmias, obesity, metabolic syndrome and renal failure. The paper will finally review the pharmacological and non-pharmacological interventions acting on the sympathetic drive. Emphasis will be given to the new approaches, such as renal nerves ablation and carotid baroreceptor stimulation, which have been shown to exert sympathoinhibitory effects.

Plasma norepinephrine is an independent predictor of adverse cerebral and cardiovascular events in type 2 diabetic patients without structural heart disease

BACKGROUND

Resting plasma norepinephrine (NE) level was reportedly related to high mortality in patients with heart failure. The current study investigated whether resting NE could predict long-term major adverse cerebral and cardiovascular events (MACCEs) in Japanese type 2 diabetic patients without heart disease.

METHODS AND SUBJECTS

We evaluated resting NE in 95 patients with type 2 diabetes who did not have severe complications. Based on the ROC curves, high NE was defined as ≥333pg/ml. Accurate follow-up information during a mean of 3.6±1.9 years was obtained in 27 high NE patients (13 female, mean age 64±12 years) and 68 low NE patients (29 female, 60±12 years).

ESSENTIAL RESULTS

The Kaplan-Meier curves revealed that MACCE-free ratio was significantly lower in the high NE patients than in the low NE patients (log-rank 10.3, p=0.0013). Cox proportional hazards regression analysis revealed that female gender (hazard ratio 7.75), low baroreflex sensitivity (hazard ratio 6.66), and high NE (hazard ratio 5.40) were independently associated with the incidence of MACCE.

PRINCIPAL CONCLUSIONS

Our results suggest that resting NE is comparably useful to identify the high-risk patients for MACCE to baroreflex sensitivity in type 2 diabetic patients. The results also suggest that pathogenic sympathetic activation leading to MACCE may be identified by the assessment of resting NE, more easily and less expensively compared to cardiac iodine 123 metaiodobenzylguanidine scintigraphy in this population.

Effect of direct renin inhibitor on left ventricular remodeling in patients with primary acute myocardial infarction

Some patients with acute myocardial infarction (AMI) have a poor prognosis due to left ventricular remodeling (LVR), resulting in the recurrence of congestive heart failure even when therapy with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) has been initiated. We investigated the effect of early administration of the direct renin inhibitor (DRI) aliskiren in combination with an ACEI or an ARB on LVR using cardiac magnetic resonance (CMR) imaging in patients with AMI.Twenty-one consecutive patients were treated with an ACEI or an ARB (non-DRI group), and another 21 consecutive patients received aliskiren 150 mg/day combined with an ACEI or an ARB (DRI group). CMR imaging was performed 7 days after AMI and 10 months later.CMR imaging revealed no significant changes in LV end-systolic volume, LV end-diastolic volume, or LV ejection fraction between the patients with and without DRI aliskiren. In the DRI group, plasma renin activity was significantly lower in both the acute and chronic phases; however, aldosterone levels were significantly lower in the acute but not the chronic phase.A low dose of aliskiren may be insufficient to maintain suppression of aldosterone under current standard therapies with an ACEI or an ARB and β-blocker in patients with primary AMI, and results in no attenuation of LVR.

Conivaptan: a selective vasopressin antagonist for the treatment of heart failure

Heart failure commonly manifests as a syndrome of salt and water retention. Arginine vasopressin plays an important role in volume homeostasis and may contribute to this syndrome seen in heart failure patients. Recently, a number of agents have been developed that antagonize the effects of vasopressin. Conivaptan, which is a dual antagonist of the V1a and V2 receptor, has shown promise in animal studies and in small scale human trials as a potential therapeutic option for the treatment of acute and chronic heart failure. Further large studies are being conducted, which may confirm the benefits of conivaptan and other vasopressin antagonists in heart failure patients.

Hypertension and depressed symptomatology: a cluster related to the activation of the renin-angiotensin-aldosterone system (RAAS). Findings from population based KORA F4 study

CONTEXT

Preliminary evidence points to aldosterone being not only prominently involved in the systemic regulation of the blood pressure but also to play a role in the pathophysiology of depression.

OBJECTIVE

We evaluated whether the combination of hypertension and depressed symptomatology is useful to screen for individuals suffering an activation of the renin-angiotensin-aldosterone system (RAAS).

DESIGN

We conducted a cross-sectional analysis in participants from the Cooperative Health Research in the Region of Augsburg (KORA) F4 Study conducted between 2006 and 2008 in Southern Germany. A total of 1805 participants of the F4 study were included in the study.

METHODS

The association between aldosterone and renin levels and the different combinations of hypertension and depressed symptomatology was examined in four different models of multiple linear regression adjusted for age, sex, creatinine levels, potassium levels, body mass index (BMI) and behavioural risk factors.

RESULTS

Individuals suffering both, depressed symptomatology and hypertension exhibited highly significantly increased aldosterone levels (p<0.001) and slightly, not significantly increased renin levels (p=0.08) compared to individuals with no depressed symptomatology and no hypertension. No significant activation of the RAAS was seen in only depressed or only hypertensive individuals.

CONCLUSIONS

The finding of highly significantly increased aldosterone levels and increased renin levels in individuals suffering both, depressed symptomatology and hypertension provides further evidence for the involvement of the RAAS in the pathogenesis of depressed symptomatology. These findings have important implications for future research concerning the pathophysiological pathways that link depression and cardiovascular disease.

Contractile responses of human thyroid arteries to vasopressin

AIMS

In the present study we investigated the intervention of nitric oxide and prostacyclin in the responses to vasopressin of isolated thyroid arteries obtained from multi-organ donors.

MAIN METHODS

Paired artery rings from glandular branches of the superior thyroid artery, one normal and the other deendothelised, were mounted in organ baths for isometric recording of tension. Concentration-response curves to vasopressin were determined in the absence and in the presence of either the vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)AVP (10(-8)M), the nitric oxide synthase inhibitor N(G)-monomethyl-l-arginine (L-NMMA, 10(-4)M), or the inhibitor of prostaglandins indomethacin (10(-6)M).

KEY FINDINGS

In artery rings under resting tension, vasopressin produced concentration-dependent, endothelium-independent contractions. The vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)AVP (10(-8)M) displaced the control curve to vasopressin 19-fold to the right in a parallel manner. The contractile response to vasopressin was unaffected by L-NMMA or by indomethacin.

SIGNIFICANCE

Vasopressin causes constriction of human thyroid arteries by stimulation of V1 vasopressin receptors located on smooth muscle cells. These effects are not linked to the presence of an intact endothelium or to the release of nitric oxide or prostaglandins. The constriction of thyroid arteries may be particularly relevant in certain pathophysiological circumstances in which vasopressin is released in amounts that could interfere with the blood supply to the thyroid gland.

Enhanced NMDA receptor-mediated intracellular calcium signaling in magnocellular neurosecretory neurons in heart failure rats

An enhanced glutamate excitatory function within the hypothalamic supraoptic and paraventricluar nuclei is known to contribute to increased neurosecretory and presympathetic neuronal activity, and hence, neurohumoral activation, during heart failure (HF). Still, the precise mechanisms underlying enhanced glutamate-driven neuronal activity in HF remain to be elucidated. Here, we performed simultaneous electrophysiology and fast confocal Ca²⁺ imaging to determine whether altered N-methyl-d-aspartate (NMDA) receptor-mediated changes in intracellular Ca²⁺ levels (NMDA-ΔCa²⁺) occurred in hypothalamic magnocellular neurosecretory cells (MNCs) in HF rats. We found that activation of NMDA receptors resulted in a larger ΔCa²⁺ in MNCs from HF when compared with sham rats. The enhanced NMDA-ΔCa²⁺ was neither dependent on the magnitude of the NMDA-mediated current (voltage clamp) nor on the degree of membrane depolarization or firing activity evoked by NMDA (current clamp). Differently from NMDA receptor activation, firing activity evoked by direct membrane depolarization resulted in similar changes in intracellular Ca²⁺ in sham and HF rats. Taken together, our results support a relatively selective alteration of intracellular Ca²⁺ homeostasis and signaling following activation of NMDA receptors in MNCs during HF. The downstream functional consequences of such altered ΔCa²⁺ signaling during HF are discussed.

New roles for renin and prorenin in heart failure and cardiorenal crosstalk

The renin-angiotensin-aldosterone-system (RAAS) plays a central role in the pathophysiology of heart failure and cardiorenal interaction. Drugs interfering in the RAAS form the pillars in treatment of heart failure and cardiorenal syndrome. Although RAAS inhibitors improve prognosis, heart failure–associated morbidity and mortality remain high, especially in the presence of kidney disease. The effect of RAAS blockade may be limited due to the loss of an inhibitory feedback of angiotensin II on renin production. The subsequent increase in prorenin and renin may activate several alternative pathways. These include the recently discovered (pro-) renin receptor, angiotensin II escape via chymase and cathepsin, and the formation of various angiotensin subforms upstream from the blockade, including angiotensin 1–7, angiotensin III, and angiotensin IV. Recently, the direct renin inhibitor aliskiren has been proven effective in reducing plasma renin activity (PRA) and appears to provide additional (tissue) RAAS blockade on top of angiotensin-converting enzyme and angiotensin receptor blockers, underscoring the important role of renin, even (or more so) under adequate RAAS blockade. Reducing PRA however occurs at the expense of an increase plasma renin concentration (PRC). PRC may exert direct effects independent of PRA through the recently discovered (pro-) renin receptor. Additional novel possibilities to interfere in the RAAS, for instance using vitamin D receptor activation, as well as the increased knowledge on alternative pathways, have revived the question on how ideal RAAS-guided therapy should be implemented. Renin and prorenin are pivotal since these are at the base of all of these pathways.

Plasma aldosterone levels are elevated in patients with pulmonary arterial hypertension in the absence of left ventricular heart failure: a pilot study

AIMS

Elevated levels of the mineralocorticoid hormone aldosterone are recognized as a modifiable contributor to the pathophysiology of select cardiovascular diseases due to left heart failure. In pulmonary arterial hypertension (PAH), pulmonary vascular remodelling induces right ventricular dysfunction and heart failure in the absence of left ventricular (LV) dysfunction. Hyperaldosteronism has emerged as a promoter of pulmonary vascular disease in experimental animal models of PAH; however, the extent to which hyperaldosteronism is associated with PAH in patients is unknown. Thus, the central aim of the current study is to determine if hyperaldosteronism is an unrecognized component of the PAH clinical syndrome.

METHODS AND RESULTS

Plasma aldosterone levels and invasive cardiopulmonary haemodynamic measurements were obtained for 25 patients referred for evaluation of unexplained dyspnoea or pulmonary hypertension. Compared with controls (n = 5), patients with PAH (n = 18) demonstrated significantly increased plasma aldosterone levels (1200.4 ± 423.9 vs. 5959.1 ± 2817.9 pg/mL, P < 0.02), mean pulmonary artery pressure (21.4 ± 5.0 vs. 45.5 ± 10.4 mmHg, P < 0.002), and pulmonary vascular resistance (PVR) (1.41 ± 0.6 vs. 7.3 ± 3.8 Wood units, P < 0.003) without differences in LV ejection fraction or pulmonary capillary wedge pressure between groups. Among patients not prescribed PAH-specific pharmacotherapy prior to cardiac catheterization, a subgroup of the cohort with severe pulmonary hypertension, aldosterone levels correlated positively with PVR (r = 0.72, P < 0.02) and transpulmonary gradient (r = 0.69, P < 0.02), but correlated inversely with cardiac output (r = -0.79, P < 0.005).

CONCLUSIONS

These data demonstrate a novel cardiopulmonary haemodynamic profile associated with hyperaldosteronism in patients: diminished cardiac output due to pulmonary vascular disease in the absence of LV heart failure.

Renin and prorenin as biomarkers in hypertension

PURPOSE OF REVIEW

This review examines the evidence that plasma renin and/or prorenin level may be used to guide therapy in hypertension and as an independent risk factor for future cardiovascular events.

RECENT FINDINGS

A large number of retrospective analyses of patient populations in clinical trials, in whom 'baseline' renin measurements were available, supports that high renin, but not high prorenin levels, are indicative of future cardiovascular disease and death, particularly in patients with kidney dysfunction and/or hypertension. The relationship is not affected by the use of renin-angiotensin system (RAS) blockers. High renin levels also tend to support the use of RAS inhibitors as first-choice antihypertensive agents. However, the added value of a renin measurement on top of traditional risk factors is modest, and the pressure response to RAS blockade, even in high-renin patients, varies widely.

SUMMARY

Measuring 'baseline' renin as a marker of future cardiovascular events or to determine the choice of drug is of limited value in an individual patient.

Association of arginine vasopressin levels with outcomes and the effect of V2 blockade in patients hospitalized for heart failure with reduced ejection fraction: insights from the EVEREST trial

BACKGROUND

Arginine vasopressin (AVP) levels are elevated in proportion to heart failure severity and are associated with higher cardiovascular mortality in ambulatory patients. However, the relationship between baseline and trends in AVP with outcomes in patients hospitalized for worsening heart failure with reduced ejection fraction is unclear.

METHODS AND RESULTS

The Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial investigated the effects of tolvaptan in patients with worsening heart failure and ejection fraction ≤40%. The present analysis examined baseline and follow-up AVP levels in 3196 EVEREST patients with valid AVP measurements. Coprimary end points included all-cause mortality, and the composite of cardiovascular mortality or heart failure hospitalization. Median follow-up was 9.9 months. Times to events were compared with univariate log-rank tests and multivariable Cox regression models, adjusted for baseline risk factors. After adjusting for baseline covariates, elevated AVP levels were associated with increased all-cause mortality (hazard ratio, 1.33; 95% confidence interval, 1.13-1.55) and cardiovascular mortality or heart failure hospitalization (hazard ratio, 1.23; 95% confidence interval, 1.08-1.39). There was no interaction of baseline AVP with treatment assignment in terms of survival (P=0.515). Tolvaptan therapy increased the proportion of patients with elevated AVP (P<0.001), but this had no effect on mortality (hazard ratio, 0.95; 95% confidence interval, 0.72-1.24).

CONCLUSIONS

Elevated baseline AVP level was independently predictive of mortality, but did not identify a group of patients who had improved outcomes with tolvaptan treatment. Tolvaptan treatment increased AVP levels during follow-up, but this incremental increase was not associated with worsened outcomes.

Mineralocorticoid receptor activation in myocardial infarction and failure: recent advances

The classical view of aldosterone actions via the mineralocorticoid receptor (MR) limited to control of fluid balance and blood pressure homoeostasis has been progressively overcome by clinical and experimental evidence emphasizing the pleiotropic role of MR activation in the pathogenesis of cardiovascular disease. Clinical studies have shown the benefit of MR blockade in patients with left ventricular dysfunction and heart failure after myocardial infarction (MI), hypertension or diabetic nephropathy. Deleterious effects of MR activation include cardiac structural and electrical remodelling, cardiovascular fibrosis, inflammation and oxidative stress. Complexity of pathophysiological role of MR derives from the presence of circulating glucocorticoids at higher concentrations than aldosterone and the equal affinity of the MR for aldosterone, cortisol and corticosterone. Recent experimental studies using different animal models and genetic tools have deeply explored the cell-specific functional role of MR in cardiovascular pathology. This review addresses emerging preclinical studies as well as ongoing clinical trials regarding MR activation in MI and failure.

The intuitive case for β-blockers in patients with ESRD

Sudden cardiac death (SCD) is common in dialysis patients accounting for up to 25% of all-cause mortality. Unlike in the general population, occlusive coronary artery disease is implicated in a minority of these deaths. Activation of the sympathetic nervous system is prevalent in the dialysis population and may underlie this high rate of SCD. β-blockers reduce SCD in the general population and, given their mode of action, β-blockers would seem to be an ideal class of agents to prevent SCD in dialysis patients. In this review, we will explore the etiology of SCD in dialysis patients and discuss the evidence supporting the use of β-blockers in patients with ESRD. We will also examine potential impediments to the use β-blocker in the dialysis population and outline directions for future trials in this area.