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The urocortins (Ucns) belong to the corticotropin-releasing factor (CRF) family of peptides and have multiple effects within the central nervous and the cardiovascular systems. With growing evidence indicating significant cardioprotective properties and cardiovascular actions of these peptides, the question arises as to whether the plasma profiles of the Ucns are altered in pathologic settings. While reports have shown conflicting results and findings have not been corroborated in multiple independent cohorts, it seems likely that plasma Ucn concentrations are elevated in multiple cardiovascular conditions. The degree of increase and accurate determination of circulating values of the Ucns requires further validation.

Mass spectrometry is a powerful technique for investigating renal pathologies and identifying biomarkers, and efficient protein extraction from kidney tissue is essential for bottom-up proteomic analyses. Detergent-based strategies aid cell lysis and protein solubilization but are poorly compatible with downstream protein digestion and liquid chromatography-coupled mass spectrometry, requiring additional purification and buffer-exchange steps. This study compares two well-established detergent-based methods for protein extraction (in-solution sodium deoxycholate (SDC); suspension trapping (S-Trap)) with the recently developed sample preparation by easy extraction and digestion (SPEED) method, which uses strong acid for denaturation. We compared the quantitative performance of each method using label-free mass spectrometry in both sheep kidney cortical tissue and plasma. In kidney tissue, SPEED quantified the most unique proteins (SPEED 1250; S-Trap 1202; SDC 1197). In plasma, S-Trap produced the most unique protein quantifications (S-Trap 150; SDC 148; SPEED 137). Protein quantifications were reproducible across biological replicates in both tissue (R2 = 0.85–0.90) and plasma (SPEED R2 = 0.84; SDC R2 = 0.76, S-Trap R2 = 0.65). Our data suggest SPEED as the optimal method for proteomic preparation in kidney tissue and S-Trap or SPEED as the optimal method for plasma, depending on whether a higher number of protein quantifications or greater reproducibility is desired.

BACKGROUND Acute decompensated heart failure (ADHF) is associated with deterioration in renal function—an important risk factor for poor outcomes. Whether ADHF results in permanent kidney damage/dysfunction is unknown. METHODS AND RESULTS We investigated for the first time the renal responses to the development of, and recovery from, ADHF using an ovine model. ADHF development induced pronounced hemodynamic changes, neurohormonal activation, and decline in renal function, including decreased urine, sodium and urea excretion, and creatinine clearance. Following ADHF recovery (25 days), creatinine clearance reductions persisted. Kidney biopsies taken during ADHF and following recovery showed widespread mesangial cell prominence, early mild acute tubular injury, and medullary/interstitial fibrosis. Renal transcriptomes identified altered expression of 270 genes following ADHF development and 631 genes following recovery. A total of 47 genes remained altered post‐recovery. Pathway analysis suggested gene expression changes, driven by a network of inflammatory cytokines centered on IL‐1β (interleukin 1β), lead to repression of reno‐protective eNOS (endothelial nitric oxide synthase) signaling during ADHF development, and following recovery, activation of glomerulosclerosis and reno‐protective pathways and repression of proinflammatory/fibrotic pathways. A total of 31 dysregulated genes encoding proteins detectable in urine, serum, and plasma identified potential candidate markers for kidney repair (including CNGA3 [cyclic nucleotide gated channel subunit alpha 3] and OIT3 [oncoprotein induced transcript 3]) or long‐term renal impairment in ADHF (including ACTG2 [actin gamma 2, smooth muscle] and ANGPTL4 [angiopoietin like 4]). CONCLUSIONS In an ovine model, we provide the first direct evidence that an episode of ADHF leads to an immediate decline in kidney function that failed to fully resolve after ≈4 weeks and is associated with persistent functional/structural kidney injury. We identified molecular pathways underlying kidney injury and repair in ADHF and highlighted 31 novel candidate biomarkers for acute kidney injury in this setting.

Background The discovery of new markers for acute kidney injury (AKI) in acute decompensated heart failure (ADHF) has been hampered by an incomplete understanding of the pathological processes underlying AKI in ADHF. Purpose In a sheep model of ADHF, we investigated changes in kidney gene expression in response to the development of, and recovery from, ADHF. Methods We collected serial kidney biopsies from 6 sheep prior to rapid cardiac pacing (day 0), after development of ADHF (pacing @220bpm for 14 days), and at the end of a 25-day (non-pacing) recovery period. Serial biopsies were supplemented with kidney samples collected post-mortem from animals undergoing a similar pacing/recovery protocol, giving a total of 11 “baseline” (B), 13 “heart failure” (HF) and 8 “recovery” (R) samples. We prepared RNA-Sequencing libraries using total RNA and Illumina TruSeq stranded mRNA library kits. Hormonal, haemodynamic, biochemical and urine measurements were also performed in all sheep before, during, and after development of ADHF. The study followed the principles of laboratory animal care and was approved by our institution's Animal Ethics Committee. Results We observed profound changes in hormonal, haemodynamic, biochemical and urine measures of cardio-renal injury in all sheep, confirming simulation of the peripheral consequences of ADHF, including clinically-relevant kidney dysfunction. This occurred in conjunction with altered kidney expression of 982 genes during ADHF development and 1,807 genes during ADHF recovery (p adj. Conclusion Our data provide the first insight into the gene pathways associated with kidney injury and repair in ADHF, in an established ovine model. Understanding the pathological processes underlying AKI in ADHF may enable discovery of novel markers for monitoring kidney injury and repair in ADHF. Figure 1. Genes altered in the kidney in ADHF Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Health Research Council of New Zealand, Heart Foundation of New Zealand

Aims Pulmonary arterial hypertension (PAH) is a devastating disease and treatment options are limited. Urocortin-2 (Ucn-2) has shown promising therapeutic effects in experimental and clinical left ventricular heart failure (HF). Our aim was to analyse the expression of Ucn-2 in human and experimental PAH, and to investigate the effects of human Ucn-2 (hUcn-2) administration in rats with monocrotaline (MCT)-induced pulmonary hypertension (PH). Methods and results Tissue samples were collected from patients with and without PAH and from rats with MCT-induced PH. hUcn-2 (5 μg/kg, bi-daily, i.p., for 10 days) or vehicle was administered to male wistar rats subjected to MCT injection or to pulmonary artery banding (PAB) to induce right ventricular (RV) overload without PAH. Expression of Ucn-2 and its receptor was increased in the RV of patients and rats with PAH. hUcn-2 treatment reduced PAH in MCT rats, resulting in decreased morbidity, improved exercise capacity and attenuated pulmonary arterial and RV remodelling and dysfunction. Additionally, RV gene expression of hypertrophy and failure signalling pathways were attenuated. hUcn-2 treatment also attenuated PAB-induced RV hypertrophy. Conclusions Ucn-2 levels are altered in human and experimental PAH. hUcn-2 treatment attenuates PAH and RV dysfunction in MCT-induced PH, has direct anti-remodelling effects on the pressure-overloaded RV, and improves pulmonary vascular function.

One-quarter of patients with acute decompensated heart failure (ADHF) experience acute kidney injury (AKI)—an abrupt reduction or loss of kidney function associated with increased long-term mortality. There is a critical need to identify early and real-time markers of AKI in ADHF; however, to date, no protein biomarkers have exhibited sufficient diagnostic or prognostic performance for widespread clinical uptake. We aimed to identify novel protein biomarkers of AKI associated with ADHF by quantifying changes in protein abundance in the kidneys that occur during ADHF development and recovery in an ovine model. Relative quantitative protein profiling was performed using sequential window acquisition of all theoretical fragment ion spectra–mass spectrometry (SWATH–MS) in kidney cortices from control sheep (n = 5), sheep with established rapid-pacing-induced ADHF (n = 8), and sheep after ~4 weeks recovery from ADHF (n = 7). Of the 790 proteins quantified, we identified 17 candidate kidney injury markers in ADHF, 1 potential kidney marker of ADHF recovery, and 2 potential markers of long-term renal impairment (differential abundance between groups of 1.2–2.6-fold, adjusted p < 0.05). Among these 20 candidate protein markers of kidney injury were 6 candidates supported by existing evidence and 14 novel candidates not previously implicated in AKI. Proteins of differential abundance were enriched in pro-inflammatory signalling pathways: glycoprotein VI (activated during ADHF development; adjusted p < 0.01) and acute phase response (repressed during recovery from ADHF; adjusted p < 0.01). New biomarkers for the early detection of AKI in ADHF may help us to evaluate effective treatment strategies to prevent mortality and improve outcomes for patients.

Aims Management of acute decompensated heart failure (ADHF) requires disparate treatments depending on the state of systemic/peripheral perfusion and the presence/absence of expanded body–fluid volumes. There is an unmet need for therapeutics that differentially treat each aspect. Atrial natriuretic peptide (ANP) plays an important role in blood pressure and volume regulation. We investigate for the first time the integrated haemodynamic, endocrine and renal effects of human ANP analogues, modified for exclusive vasodilatory (ANP-DRD) or diuretic (ANP-DGD) activities, in normal health and experimental ADHF. Methods and results We compared the effects of incremental infusions of ANP analogues ANP-DRD and ANP-DGD with native ANP, in normal (n = 8) and ADHF (n = 8) sheep. ANP-DRD administration increased plasma cyclic guanosine monophosphate (cGMP) in association with dose-dependent reductions in arterial pressure in normal and heart failure (HF) sheep similarly to ANP responses. In contrast to ANP, which in HF produced a diuresis/natriuresis, this analogue was without significant renal effect. Conversely, ANP-DGD induced marked stepwise increases in urinary cGMP, urine volume, and sodium excretion in HF comparable to ANP, but without accompanying vasodilatory effects. All peptides increased packed cell volume relative to control in both states, and in HF, decreased left atrial pressure. In response to ANP-DRD-induced blood pressure reductions, plasma renin activity rose compared to control only during the high dose in normals, and not at all in HF—suggesting relative renin inhibition, with no increase in aldosterone in either state, whereas renin and aldosterone were both significantly reduced by ANP-DGD in HF. Conclusion These ANP analogues exhibit distinct vasodilatory (ANP-DRD) and diuretic/natriuretic (ANP-DGD) activities, and therefore have the potential to provide precision therapy for ADHF patients with differing pathophysiological derangement of pressure–volume homeostasis.

Both adrenomedullin 2 (AM2) and sympathetic nerve activity (SNA) have been shown to be involved in regulating cardiovascular activity, but whether any interaction between these two systems exists remains to be determined. In this study, we examine the effects of intravenous AM2 infusions on SNA directed toward the heart (cardiac SNA (CSNA)) in healthy sheep studied in the conscious state. In response to AM2, arterial pressure was reduced (P = 0.005) with both heart rate (P

Phosphodiesterase-9 (PDE9) reduces natriuretic peptide (NP) signaling and may be involved in the pathophysiology of heart failure (HF).This study investigated for the first time the integrated hemodynamic, endocrine, and renal effects of phosphodiesterase-9 inhibition (PDE9-I).A total of 8 normal sheep and 8 sheep with pacing-induced HF received incremental intravenous boluses of PDE9-I (30, 100, and 300 mg PF-04749982 at 1-h intervals).PDE9-I dose-dependently increased plasma cyclic guanosine monophosphate (cGMP) in normal sheep (p 0.05) while concurrently reducing circulating atrial natriuretic peptide levels (p 0.01). Similar trends were evident in HF, resulting in significant elevations in the cGMP/NP ratio in both states (p 0.001 and p 0.05, respectively). PDE9-I also produced progressive falls in arterial pressure (HF: p 0.001), atrial pressure (Normal: p 0.001; HF: p 0.001), and peripheral resistance (HF: p 0.001), and transiently increased cardiac output at the top dose (Normal: p 0.05; HF: p 0.001). Inhibition of PDE9 had a negligible effect on circulating hormones at the lower doses, but post-high dose, acutely increased renin activity (Normal: p 0.001; HF: p 0.05), vasopressin (Normal: p 0.001; HF: p 0.01), and cyclic adenosine monophosphate (HF: p 0.001). Plasma aldosterone increased briefly after high-dose PDE9-I in normal sheep, and fell following the top dose in HF. PDE9-I dose-dependently increased urinary cGMP in both states (both p 0.001). In HF, this was associated with increases in urine volume (p 0.01), sodium excretion (p 0.01), and creatinine clearance (p 0.001).PDE9-I improves NP efficacy in conjunction with beneficial hemodynamic and renal effects in experimental HF. These results support a role for PDE9 in HF pathophysiology and suggest its inhibition may constitute a novel therapeutic approach to this disease.

Simple Summary Human heart failure (HF) is a complex clinical syndrome that can be caused by a variety of diseases. While long-term high blood pressure and heart attacks are major contributing factors, there can be many diseases of the heart and circulation that contribute to the development of HF. Although there have been salutary improvements in the medical management of HF over the last 30 years, ongoing ill effects of living with the syndrome and the persistently high death rates mean there is an irrefutable need for new and improved treatment options. Well-characterized animal models have contributed, and continue to contribute, much to the advancement of clinical care. This review will summarize the main large animal models of HF developed to date. Studies utilizing these large animal models are an essential step leading to the development of novel pharmaceutical and device-based therapies before they can undergo definitive clinical trials. This review will discuss the various benefits of different large animal models of HF and highlight some key deficiencies to date. There is clearly a need for ongoing development of clinically relevant large animal models of HF. Abstract Heart failure (HF) is the final common end point of multiple metabolic and cardiovascular diseases and imposes a significant health care burden worldwide. Despite significant improvements in clinical management and outcomes, morbidity and mortality remain high and there remains an indisputable need for improved treatment options. The pathophysiology of HF is complex and covers a spectrum of clinical presentations from HF with reduced ejection fraction (HFrEF) (≤40% EF) through to HF with preserved EF (HFpEF), with HFpEF patients demonstrating a reduced ability of the heart to relax despite an EF maintained above 50%. Prior to the last decade, the majority of clinical trials and animal models addressed HFrEF. Despite growing efforts recently to understand underlying mechanisms of HFpEF and find effective therapies for its treatment, clinical trials in patients with HFpEF have failed to demonstrate improvements in mortality. A significant obstacle to therapeutic innovation in HFpEF is the absence of preclinical models including large animal models which, unlike rodents, permit detailed instrumentation and extensive imaging and sampling protocols. Although several large animal models of HFpEF have been reported, none fulfil all the features present in human disease and few demonstrate progression to frank decompensated HF. This review summarizes well-established models of HFrEF in pigs, dogs and sheep and discusses attempts to date to model HFpEF in these species.

The novel peptide dwarf open reading frame (DWORF), highly conserved across species and expressed almost exclusively in cardiac ventricular muscle, may play a role in cardiac physiology and pathophysiology. The effect of direct administration of DWORF in the intact heart has not previously been examined. Accordingly, we investigated the cardiac effects of DWORF (1−30 nM) in normal isolated perfused rat hearts and hearts undergoing ischaemia/reperfusion (I/R) injury, and evaluated potential mechanisms of action. Exogenous DWORF at the top dose (30 nM) increased perfusion pressure (PP) in normal hearts, which indicates coronary vasoconstriction; and during post-ischaemic reperfusion, DWORF increased PP in a dose-dependent manner. In I/R hearts, DWORF at the top dose also increased left ventricular end-diastolic pressure and maximum and minimum derivatives of left ventricular pressure noted dP/dt(max) and dP/dt(min), respectively, without affecting developed pressure (DP). Co-infusion of DWORF with Diltiazem, an l -type Ca2+ channel blocker (1μM), in I/R hearts attenuated the falls in DP, dP/dt(max) and dP/dt(min) observed with Diltiazem alone. DWORF co-infusion with both Diltiazem and Y27632 (1μM) (a Rho-Kinase inhibitor) reversed the coronary vasodilator effect of the inhibitors administered alone. In conclusion, we provide the first evidence that DWORF has coronary vasoconstrictor actions in normal hearts and when administered during reperfusion in an ex-vivo model of cardiac I/R injury, and also exhibits positive cardiac inotropic activity in the latter setting. DWORF’s effect on ventricular contractile function appears to be dependent on the l -type Ca2+ channel, whereas Rho-Kinase activity may be related to the coronary vasoconstrictor effects of DWORF.

While it is well established that centrally injected angiotensin II (Ang II) has potent actions on sympathetic nervous activity (SNA), it is less clear whether peripheral Ang II can immediately stimulate SNA. In particular, the contribution of cardiac sympathetic nerve activity (CSNA) to the acute pressor response is unknown. We therefore examined the effect of incremental doses of intravenous Ang II (3, 6, 12, 24, and 48 ng/kg/min each for 30 min) on CSNA in eight conscious sheep. Ang II infusions progressively increased plasma Ang II up to 50 pmol/l above control levels in dose-dependent fashion (P

The (pro)renin receptor [(P)RR] is implicated in the pathogenesis of cardiovascular disease. We investigated the effects of (P)RR blockade after myocardial infarction (MI) in a mouse coronary-ligation model.Mice underwent sham control surgeries (n = 8) or induction of MI followed by 28 days' treatment with a vehicle control (n = 8) or (P)RR antagonist (n = 8). Compared with sham control subjects, MI + vehicle mice demonstrated reduced left ventricular (LV) ejection fraction (LVEF: P.001) and fractional shortening (P.001), and increased LV end-systolic and -diastolic volumes (LVESV: P.001; LVEDV: P.001) 28 days after MI. In addition, MI decreased LV posterior wall and septal diameters (both P.001), increased heart weight-body weight ratios (P.05), LV collagen deposition, and cardiomyocyte diameter (both P.001), and up-regulated collagen 1 (P.01) and β-myosin heavy chain (β-MHC: P.05) mRNA. Compared with MI + vehicle mice, (P)RR antagonism after MI reduced infarct size (P.01), improved LVEF (P.001), fractional shortening (P.001), and stroke volume (P.05), and decreased LVESV (P.001) and LVEDV (P.001). (P)RR antagonism also reversed MI-induced transmural thinning (P.001) and reduced LV fibrosis (P.01), cardiomyocyte size (P.001), and ventricular collagen 1 (P.01), β-MHC (P = .06), transforming growth factor β1 (P.01), and angiotensin-converting enzyme (P.05) expression.The present study found that (P)RR blockade after MI in mice ameliorates infarct size, cardiac fibrosis/hypertrophy, and cardiac dysfunction and identifies the receptor as a potential therapeutic target in this setting.

Background Renal dysfunction is a frequent complication and crucial determinant of outcome in acute decompensated heart failure (ADHF). The aim of the study was to assess urocortin 2 (Ucn2) as a short-term therapy in ADHF with a focus on its renal effects. Comparison was made with dobutamine to distinguish effects beyond pure inotropism. Methods Sheep with ADHF received a 2-day infusion of a vehicle-control, Ucn2 or dobutamine (n=6/grp). Results Compared to controls, Ucn2 and dobutamine produced matched improvements in cardiac contractility and output and arterial pressure, whereas reductions in central venous and left atrial pressures were greater with Ucn2. Both agents comparably repressed ADHF-activated hormone systems with the exception of the natriuretic peptides, which fell significantly during dobutamine but not Ucn2. While Ucn2 and dobutamine increased creatinine clearance and urine volume similarly, only Ucn2 induced a significant natriuresis. Ucn2 also decreased collagen deposition in the heart and kidney and suppressed gene expression of collagen-1, transforming growth factor-β1, components of the angiotensin system (angiotensinogen, angiotensin-converting enzyme, type-1 receptor) and markers of hypertrophy (GATA binding protein-4, β-myosin heavy chain), apoptosis (caspase3) and inflammation/injury (interleukin-18, cystatin C, neutrophil gelatinase-associated lipocalin, kidney injury molecule-1) in these tissues, while increasing cardiac natriuretic peptide mRNA. In contrast, dobutamine produced reduced or opposite effects on expression of these factors. Conclusions Ucn2 administration in ADHF has favorable effects on hemodynamics, the natriuretic peptides and tissue mediators of inflammation, fibrosis, apoptosis and hypertrophy that stand in contrast to dobutamine. These data support Ucn2's potential as a renoprotective therapeutic in this setting.

Urocortin (Ucn)-2 - corticotropin-releasing hormone receptor 2 signaling has favorable effects in the cardiovascular system, including coronary vasodilatation, with increased coronary blood flow and conductance and augmented cardiac contractility and output, as well as protection against ischemia/reperfusion injury. Indeed, several animal studies have confirmed the salutary therapeutic effects of Ucn-2 in chronic heart failure, with improvements in cardiac performance and animal survival. In addition, recent clinical trials have demonstrated the benefits of Ucn-2 in patients with stable chronic heart failure on optimal medical therapy.

The impact of chronic urocortin 2 (Ucn2) treatment after myocardial infarction (MI) has not previously been investigated. In this study, we examined the effects of 30-day Ucn2 administration (415 μg·kg·d SC per day) in mice post-MI. Compared with surgical sham + vehicle controls (n = 10), MI + vehicle animals (n = 10) after 30 days demonstrated decreased ejection fraction (75.6 ± 1.2 vs. 43.6% ± 0.8%, P < 0.001) and fractional shortening (38.20 ± 0.83 vs. 18.4% ± 0.54%, P < 0.001) in association with increased heart weight-to-body weight ratio (4.57 ± 0.25 vs. 5.29 ± 0.18, P < 0.01), left ventricular (LV) mass (91 ± 7 vs. 126 ± 8 mg, P < 0.01), LV internal diameters at both systole (1.91 ± 0.14 vs. 3.45 ± 0.09 mm, P < 0.001) and diastole (3.14 ± 0.15 vs. 4.25 ± 0.10 mm, P < 0.001), LV end systolic volumes (0.02 ± 0.01 vs. 0.11 ± 0.01 mL, P < 0.001), and ventricular collagen 1 and β-myosin heavy chain gene expression. Compared with MI + vehicle mice, MI + Ucn2 animals (n = 10) exhibited significantly reduced infarct size (4.00 ± 0.39 vs. 1.83 ± 0.44 mm, P < 0.01), heart weight-to-body weight ratio (4.75 ± 0.19, P = 0.06), LV mass (101 ± 6 mg, P < 0.01), LV internal diameters (systole 2.61 ± 0.09 mm, P < 0.001; diastole 3.78 ± 0.09 mm, P < 0.001), and end systolic volumes (0.14 ± 0.02 mL, P < 0.01) in conjunction with improved ejection fraction (65.2% ± 0.9%, P < 0.001) and fractional shortening (18.4 ± 0.5 vs. 30.5% ± 0.5%, P < 0.001). Ucn2 treatment also decreased collagen 1 and β-myosin heavy chain expression. In conclusion, chronic Ucn2 treatment significantly improves cardiovascular function and attenuates cardiac injury and remodeling in experimental MI.

The urocortins (Ucns), endogenous peptides belonging to the corticotropin-releasing factor (CRF) family, are increasingly recognized as having diverse and important multi-system functions, especially within the cardiovascular system. The biological actions of the three Ucns (Ucn1, Ucn2, Ucn3) are mediated via G-protein-coupled CRF receptors, with both peptides and receptors widely distributed throughout tissues and organs contributing to pressure/volume homeostasis including the heart, vasculature, kidneys and adrenals. The Ucns activate a variety of signaling cascades in cardiomyocytes, vascular smooth muscle cells and endothelial cells including, but not limited to, adenyl cyclase/cAMP and several kinase pathways, with downstream effects comprising vasodilation, augmented cardiac contractility, and protection against hypoxic injury. Increasing evidence suggests the Ucns may be clinically significant molecules in the pathogenesis, treatment and/or management of several conditions, with some of the most compelling data demonstrating a therapeutic potential for the peptides in the setting of heart failure. Circulating levels of the Ucns are elevated in this setting, and antagonism of the endogenous peptides exacerbates manifestations of the syndrome in animal models. All three Ucns exert salutary hemodynamic, neurohormonal and renal effects in experimental heart failure and recent clinical trials have demonstrated hemodynamic benefits of Ucn2 administration.

Study of microRNA (miRNAs) using sheep models is limited due to lack of miRNA information. We therefore investigated oar-miRNAs and their regulation in an ovine model of heart failure (HF). Left ventricular (LV) tissue was collected from normal (Cont), HF (LV pacing @ ~220bpm for 13-days) and HF-recovery sheep (HF-R, 26-days after pacing cessation). MiRNA expression was profiled using next-generation sequencing (NGS) and miRNA array, and validated by stem-loop qPCR. Detected sequences were mapped against the ovine genome (Oar v4.0) and aligned with known miRNAs (miRBase v21). A total of 36,438,340 raw reads were obtained with a peak distribution of 18–23 nt. Of these, 637 miRNAs were detected by NGS and mapped to the ovine genome. With cut-off at 10 counts, 275 novel miRNAs were identified (with 186 showing 100% alignment and 89 showing 70–99% alignment with human/mouse and/or rat miRNAs, respectively), and 78 known oar-miRNAs. Cardiac-enriched miRNA-1, -133a, -208a/b and -499 were highly expressed in the LV. With HF induction, miRNA-133b-3p, -208b-3p, -125a-5p, -125b-5p, -126-3p, -21-5p, -210-3p, -29a-3p, -320a and -494-3p were significantly up-regulated relative to Cont and tended to return to normal levels following HF-recovery. This study has expanded the sheep miRNA database, and demonstrated HF-induced regulation of miRNAs.

The reported effects of atrial natriuretic peptide (ANP) on sympathetic nerve activity (SNA) are variable, dependent on concomitant hemodynamic actions, and likely to be regionally differentiated. There are few reports of the effect of B-type natriuretic peptide (BNP) on SNA and none have measured cardiac SNA (CSNA) by direct microneurography. We measured the effects of low-dose ANP and BNP (2.4 pmol·kg−1·min−1 infused for 120 min) on CSNA and hemodynamics in conscious sheep ( n = 8). While there was a trend for mean arterial pressure and cardiac output to fall with both ANP and BNP, changes were not significant compared with vehicle control. However, BNP did significantly reduce systolic arterial (97 ± 4.2 vs. 107 ± 6.8 mmHg during control; P = 0.043) and pulse pressures (0.047) and increase heart rate (110 ± 6.7 vs. 96 ± 7.3 beats/min; P = 0.044). Trends for these hemodynamic parameters to change with ANP did not achieve statistical significance. ANP also had no significant effect on any CSNA parameters measured. In contrast, BNP induced a rise in both CSNA burst frequency (∼20 bursts/min higher than control, P = 0.011) and burst area (∼40% higher than control, P = 0.013). BNP-induced rises in burst incidence (bursts/100 beats), and burst area per 100 beats, however, were not significant. In conclusion, BNP infused at low doses that only had subtle effects on hemodynamics increased CSNA burst frequency and burst are per minute. This increase in CSNA may in large part be secondary to an increase in heart rate as CSNA burst incidence and burst area per 100 beats were not significantly increased. This study provides no evidence for inhibition of CSNA by natriuretic peptides.

The rationale for intrathoracic impedance (Z) detection of worsening heart failure (HF) presupposes that changes in Z reflect changes in pulmonary congestion, but is confounded by poor specificity in clinical trials. We therefore tested the hypothesis that Z is primarily affected by tissue/water content in proximity to electrodes rather than by lung water distribution between electrodes through the use of a new computational model for deriving the near-field impedance contributions from the various electrodes. Six sheep were implanted with a left atrial pressure (LAP) monitor and a cardiac resynchronization therapy device which measured Z from six vectors comprising of five electrodes. The vector-based Z was modelled as the summation of the near-field impedances of the two electrodes forming the vector. During volume expansion an acute increase in LAP resulted in simultaneous reductions in the near-field impedances of the intra-cardiac electrodes, while the subcutaneous electrode showed several hours of lag (all p

The use of animal models has been crucial to our understanding of the causation, progression and therapeutic management of disease. The rapid ventricular pacing model of heart failure (HF) in sheep closely replicates the haemodynamic, endocrine and metabolic characteristics of severe human HF, and h

A left atrial pressure (LAP) monitoring system was developed for guiding the management of patients with heart failure. The LAP sensor is implanted into the left atrium via transseptal catheterization and affixed to the interatrial septum by nitinol anchors. The long-term safety of permanent implantation of the LAP sensor in patients was evaluated based on the comparative pathology in animals. Tissue specimens of the LAP sensor from 7 patients, 49 canines, and 14 ovine were examined for thrombosis and tissue overgrowth. Implant duration ranged from 22 to 1,686 days. Gross examination showed minimal-to-moderate tissue overgrowth with no evidence of migration, erosion, or perforation. There was no excessive host-to-device reaction or active thrombogenesis in any of the subjects that followed the antithrombotic therapy protocol. Micro-computed tomography scanning confirmed the structural integrity of the device. Low vacuum scanning electron microscopy and histology showed neoendocardial tissue overgrowth with no inflammation or fibrin. The pathology of both animal models was found to closely approximate the pathology in humans and favorably supports the long-term safety of the device.

Background— Mineralocorticoid receptor antagonists (MRAs) have become established therapy in heart failure (HF). Urocortin 2 (Ucn2) is a novel peptide with potential in the treatment of this disease. The present study investigated the interactions of acute administration of Ucn2 and an MRA in experimental HF. Methods and Results— Ucn2 and an MRA (canrenoic acid [CA]) were infused for 4 hours, both singly and together, in 8 sheeps with pacing-induced HF. Ucn2, when administered as an adjunct to CA, further improved hemodynamic indices relative to that achieved by CA alone, producing additional increases in cardiac output and decreases in left atrial pressure and peripheral resistance but without eliciting a supplementary reduction in arterial pressure. Ucn2 cotreatment reversed CA-induced rises in circulating aldosterone levels, and also significantly reduced plasma renin activity, angiotensin II, and vasopressin concentrations. Although both CA and Ucn2 infusion produced a diuresis and natriuresis, responses with Ucn2 and Ucn+CA were 2- to 3-fold greater than that elicited by separate CA. Ucn2 cotherapy additionally increased urine potassium and creatinine excretion. In contrast to the rise in plasma potassium induced by CA, Ucn2 cotreatment reduced potassium concentrations. Conclusions— Ucn2 cotreatment with an MRA in HF further improved hemodynamics relative to that achieved by CA alone, while also reducing plasma renin activity, angiotensin II, aldosterone and vasopressin levels, and enhancing renal function. Importantly, Ucn2 prevented CA-induced rises in plasma potassium. These data demonstrate a favorable profile of effects with short-term adjunct Ucn2 therapy and an MRA in HF.

Introduction: The sheep ( Ovis aries ) provides a large animal model in cardiovascular research including heart failure (HF). However, microRNA (miR) related work in the sheep model has been limited due to a paucity of information regarding oar-miR. The aim of this study was to identify novel oar-miRs in myocardium and examine their regulation in HF and HF recovery. Methods: Heart tissue was harvested from sheep undergoing 1. HF induced by rapid left ventricular (LV) pacing at 225bpm for 14 days, 2. HF recovery (HF-R) after discontinuation of pacing for an additional 14 days and 3. Sham. LV miRs were examined using next generation deep sequencing (NGS), miR array and stem-loop qPCR. Sequences were aligned with miRBase v20.0 and mapped to ovine genome and miRBase Mature BLAST search engine. Plasma was collected to assess natriuretic peptides (ANP and BNP). Results: Three miR libraries were generated from NGS and a total of 619 miRs were detected. Of these, 93 were oar-miRs; 49 novel miRs (high confidence) mapped to ovine genome and perfectly aligned to mature miRs in other organisms (miRBase v20.0); 69 putative novel miRs (high confidence) that mapped to ovine genome and aligned partially to mature miRs of other species in miRBase v20.0; 168 miRs (low confidence) that mapped to ovine genome but unaligned to any known mature miRs; and 240 miRs (low confidence) that were unmapped to the sheep genome but aligned to either miRBase mature hsa-/mmu-/rno-miRs. Plasma BNP and ANP increased 19-folds and 18- folds respectively in HF, and returned to baseline in HF-R. MiR levels in HF model were examined using miR array. About 1000 miRs were detected from array and at least 301 of them were overlapped with NGS data. Using miR array profiling followed by stem-loop qPCR validation, we found that myocardial enriched miR-133b-3p, miR-208b-3p, miR-21-5p and miR-125a-5p, -125b-5p, -126-3p, -210-3p, and 29a-3p were significantly upregulated in HF (p Conclusion: We identified 118 novel oar-miRs with high confidence and 408 potential oar-miRs, which is a solid foundation for miR function studies using sheep models. We also identified miR changes in HF and HF-R.

BACKGROUND AND PURPOSE The urocortin (Ucn) peptides are emerging as potential therapeutic targets for heart disease. However, pharmacokinetic (PK) and pharmacodynamic (PD) data are lacking. Therefore, we investigated the PK/PD for all three Ucns. EXPERIMENTAL APPROACH Seven sheep received 1 µg·kg(-1) boluses of Ucn1, Ucn2 and Ucn3. Population PK/PD models were developed to describe the time course of the haemodynamic effects. RESULTS The population estimate for Ucn1 clearance (0.486 L·h(-1)) was lower than that for Ucn2 (21.7 L·h(-1)) and Ucn3 (220 L·h(-1)), while steady-state volumes of distribution were similar for Ucn1 and Ucn2 (∼8 L) but substantially larger for Ucn3 (23.5 L). Ucn1 disposition was adequately described by a two-compartment model, with a one-compartment model required for Ucn2 and Ucn3. The half-life for Ucn1 was 2.9 h (α phase) and 8.3 h (β phase), and 15.7 and 4.4 min for Ucn2 and Ucn3 respectively. All Ucns produced significant increases in heart rate, cardiac output and left ventricular systolic and mean arterial pressures, and decreases in left atrial pressure and peripheral resistance. Delayed-effect pharmacodynamic models best described the time course of haemodynamic responses, with effects more rapid and less prolonged for Ucn2 and Ucn3 than Ucn1. Similar and physiologically plausible estimated baseline (E(0)) effects were exhibited by all Ucns, whereas EC(50) values were generally greater for Ucn1. CONCLUSIONS AND IMPLICATIONS Relative to Ucn1, both the PK and haemodynamic responses to Ucn2 and Ucn3 occurred more rapidly. Our data provide important comparative information, useful to the rational design of future clinical studies.

AM5 (adrenomedullin 5), a newly described member of the CGRP (calcitonin gene-related peptide) family, is reported to play a role in normal cardiovascular physiology. The effects of AM5 in HF (heart failure), however, have not been investigated. In the present study, we intravenously infused two incremental doses of AM5 (10 and 100 ng/min per kg of body weight each for 90 min) into eight sheep with pacing-induced HF. Compared with time-matched vehicle control infusions, AM5 produced progressive and dose-dependent increases in left ventricular dP/dt(max) [LD (low dose), +56 mmHg/s and HD (high dose), +152 mmHg/s] and cardiac output (+0.83 l/min and +1.81 l/min), together with decrements in calculated total peripheral resistance (−9.4 mmHg/min per litre and −14.7 mmHg/min per litre), mean arterial pressure (−2.8 mmHg and −8.4 mmHg) and LAP (left atrial pressure; −2.6 mmHg and −5.6 mmHg) (all P

There is an increasing body of evidence suggesting a role for the urocortin (Ucn) peptides in blood pressure regulation and in the pathophysiology of cardiovascular disease. Both Ucn1 and Ucn2 have recently been shown to inhibit cardiac sympathetic nerve activity (CSNA) in sheep. However, there are few studies reporting the effects of Ucn3 on the sympathetic nervous system. Hence, this study performed in normal conscious sheep examines the effects of Ucn3 on CSNA. Intravenous Ucn3 (administered at doses of 25 and 100 μg) caused transient falls in arterial pressure (P = 0.025), more prolonged rises in heart rate (P < 0.001), and falls in stroke volume (P < 0.001) and peripheral resistance (P = 0.018). CSNA, measured as burst area and burst incidence, fell in a dose-dependent manner after Ucn3 bolus (all P < 0.001). CSNA burst frequency tended to be reduced after high-dose Ucn3. Ucn3 had no significant effect on plasma catecholamine levels. In conclusion, this study reports for the first time that Ucn3 induces potent inhibition of sympathetic traffic directed toward the heart. This provides further support for a role for Ucn3 in pressure and volume homeostasis and suggests that further investigation of potential therapeutic applications for Ucn3 in cardiovascular disease is warranted.

Although acute administration of urocortin 2 has beneficial actions in heart failure, the integrated hemodynamic, hormonal, and renal effects of sustained urocortin 2 treatment in this disease have not been investigated. In the current study, we administered a 4-day infusion of a vehicle control (0.9% saline; n=6) or urocortin 2 (0.75 μg/kg per hour; n=6) to sheep with pacing-induced heart failure. Compared with time-matched controls, infusion of urocortin 2 produced rapid (30-minute) and persistent (4-day) improvements in cardiac contractility (day 4: control 905±73 versus urocortin 2 1424±158 mm Hg/s; P P P P P P P P P P P P P P P P

Monitoring of HF (heart failure) with intracardiac pressure, intrathoracic impedance and/or natriuretic peptide levels has been advocated. We aimed to investigate possible differences in the response patterns of each of these monitoring modalities during HF decompensation that may have an impact on the potential for early therapeutic intervention. Six sheep were implanted with a LAP (left atrial pressure) sensor and a CRT-D (cardiac resynchronization therapy defibrillator) capable of monitoring impedance along six lead configuration vectors. An estimate of ALAP (LAP from admittance) was determined by linear regression. HF was induced by rapid ventricular pacing at 180 and 220 bpm (beats/min) for a week each, followed by a third week with daily pacing suspensions for increasing durations (1–5 h). Incremental pacing induced progressively severe HF reflected in increases in LAP (5.9 ± 0.4 to 24.5 ± 1.6 mmHg) and plasma atrial (20 ± 3 to 197 ± 36 pmol/l) and B-type natriuretic peptide (3.7 ± 0.7 to 32.7 ± 5.4 pmol/l) (all P

Background— Urocortin 2 (Ucn2), a novel peptide with therapeutic potential in heart failure, and diuretics have opposing effects on renal function and the renin-angiotensin-aldosterone system. Because any prospective new treatment is likely to be used in conjunction with standard diuretic therapy, it is necessary to investigate the combined effects of these agents. Methods and Results— Ucn2 and furosemide were administered for 3 hours, both singly and combined, in 7 sheep with pacing-induced heart failure. Compared with time-matched controls, separate Ucn2 and furosemide administration significantly increased urine output (furosemide>Ucn2), urine sodium (furosemide>Ucn2), potassium (furosemide>Ucn2), and creatinine excretion (Ucn2>furosemide) and creatinine clearance (Ucn2>furosemide). Compared with furosemide treatment alone, Ucn2+furosemide produced a further diuresis ( P P P P Ucn2), left atrial pressure (Ucn2+furosemide>Ucn2>furosemide), and peripheral resistance (Ucn2+furosemide=Ucn2>furosemide), whereas only Ucn2, singly and in combination with furosemide, increased cardiac output and dP/dt(max). In contrast to the increase in plasma renin activity elicited by furosemide alone, Ucn2 and Ucn2+furosemide markedly reduced plasma renin activity. All active treatments decreased plasma aldosterone (Ucn2+furosemide=Ucn2>furosemide), whereas only Ucn2 and Ucn2+furosemide reduced vasopressin and natriuretic peptide concentrations. Conclusion— Ucn2 cotreatment with furosemide enhanced hemodynamic and renal function and diuretic responsiveness (without additional potassium depletion) in experimental heart failure. Furthermore, Ucn2 reversed furosemide-induced increases in plasma renin activity and induced greater decreases in plasma aldosterone and vasopressin. These data indicate that adjunct Ucn2 therapy with diuretics in heart failure is beneficial.

Background— Adrenomedullin 2 (AM2) is a novel member of the calcitonin gene-related peptide family that is thought to play a regulatory role in circulatory homeostasis under normal physiological conditions. The effects of AM2 in heart failure have not been investigated previously. Methods and Results— Two incremental doses of human AM2 (10 and 100 ng[kg�min] for 90 minutes each) were given by intravenous infusion to 8 sheep with pacing-induced heart failure. Compared with time-matched control infusions, AM2 produced dose-dependent increases in left ventricular dP/dt(max) (control 1168�138 mm Hg/s versus AM2 high-dose 1402�130 mm Hg/s; P P P P P P P P P P =0.08). Plasma vasopressin, endothelin-1, and catecholamines levels were also unchanged by AM2. Renal effects of AM2 included increased excretion of sodium ( P P P P P =0.068). Conclusion— These results indicate that AM2 administration has favorable effects on cardiovascular, endocrine, and renal indexes in heart failure and identify the peptide as a potential therapeutic target in this disease.

OBJECTIVES Urocortin 1 (Ucn1) and the sympathetic nervous system both participate in cardiac and circulatory regulation, but little is known about their possible interactions. METHODS We report the effects of Ucn1 on the cardiac sympathetic nerve activity (CSNA), haemodynamics and plasma catecholamines in normal sheep. RESULTS Bolus intravenous administration of Ucn1 at 2.5 and 10 microg in seven sheep had no significant effect on haemodynamic parameters, including heart rate, mean arterial pressure (MAP) and cardiac output. At these doses, however, Ucn1 administration reduced CSNA, with burst frequency (P = 0.011), burst incidence (P = 0.015) and burst area (P = 0.012) all significantly reduced in a dose-related manner compared with a time-matched control. At higher doses (25 and 100 microg; n = 5 sheep), Ucn1 induced significant rises in heart rate (P < 0.001) and cardiac output (P = 0.03) and reduced peripheral resistance (P = 0.03), but had no effect on MAP. Ucn1 administration at the higher doses reduced CSNA, with burst incidence (P < 0.001), burst area/min (P = 0.001) and burst area/100 beats (P < 0.001) all significantly reduced in a dose-related manner compared with a time-matched control. There was no change in plasma catecholamines at any dose. CONCLUSION The present study shows that Ucn1 induces potent inhibition of sympathetic traffic to the heart at doses both above and below the threshold for direct actions of Ucn1 on the myocardium. These findings suggest an important role for Ucn1 in cardiovascular homeostasis and warrant further investigation for potential therapeutic applications in acute myocardial injury and heart disease.

Aims To document the haemodynamic, neurohormonal, and renal responses to Urocortin 2 (UCN2) infused in human heart failure (HF). Methods and results Eight male patients with HF [left ventricular ejection fraction (LVEF) < 40%, NYHA class II–III] received placebo and 25 [low dose (LD)] and 100 µg [high dose (HD)] of UCN2 intravenously over 1 h in a single-blind, placebo-controlled, dose-escalation design. UCN2 increased cardiac output (CO) (mean peak increments ± SEM; placebo 0.3 ± 0.1; LD 1.0 ± 0.3; HD 2.0 ± 0.2 L/min; P < 0.001) and LVEF (0.0 ± 1.5; LD 5.9 ± 2.1; HD 14.1 ± 2.7%; P = 0.001) and decreased mean arterial pressure (placebo 6.7 ± 1.3; LD 11.4 ± 1.7; HD 19.4 ± 3.3 mmHg; P = 0.001), systemic vascular resistance (SVR) (placebo 104 ± 37; LD 281 ± 64; HD 476 ± 79 dynes s/cm5; P < 0.003), and cardiac work (CW) (placebo 48 ± 12; LD 66 ± 22; HD 94 ± 13 mmHg/L/min; P < 0.001). No significant effect on vasoconstrictor/volume-retaining neurohormones was noted. UCN2 decreased urinary volume ( P = 0.035) but not creatinine excretion ( P = 0.962). Conclusion Intravenous UCN2 in HF induced increases in CO and LVEF with falls in SVR and CW. No hormone response occurred. The role of UCN2 in circulatory regulation and its potential therapeutic application in heart disease warrant further investigation.

In addition to haemodynamic actions, Ucn1 (urocortin 1) has been reported to affect a number of hormonal systems; however, it remains unclear whether Ucn1 modulates circulating hormones under physiological conditions. Accordingly, in the present study, we have examined the effects of Ucn1 on haemodynamics, hormones and renal indices in normal conscious sheep subjected to a nitroprusside-induced hypotensive stimulus designed to alter hormonal levels within the physiological range. Ucn1 administration did not alter the haemodynamic response to nitroprusside-induced hypotension. However, compared with the rise observed on the control day, plasma ANP (atrial natriuretic peptide; P=0.043), BNP (brain natriuretic peptide; P=0.038) and endothelin-1 (P=0.011) levels were reduced following Ucn1 administration. Associated with this significant reduction in natriuretic peptides, the increase in urinary sodium output associated with rising pressures post-nitroprusside was abolished following Ucn1 administration (P=0.048). Ucn1 had no significant effect on the response of hormones of the renin–angiotensin–aldosterone system or the hypothalamo–pituitary–adrenal axis. In conclusion, Ucn1, administered at physiologically relevant levels during nitroprusside-induced hypotension, attenuates the secretion/release of endothelin-1 and the cardiac natriuretic peptides ANP and BNP. Suppression of ANP and BNP probably led to an attenuated natriuretic response to recovery from acute hypotension. The threshold for the action of Ucn1 on the natriuretic peptides and endothelin-1 appears to be below that of other actions of Ucn1.

Urocortin 2 Infusion in Healthy Humans: Hemodynamic, Neurohormonal, and Renal ResponsesMark E. Davis, Christopher J. Pemberton, Timothy G. Yandle, Steve F. Fisher, John G. Lainchbury, Christopher M...

This study investigated whether gene expression profiles of myofibroblasts derived from infarcted myocardium differ from normal cardiac fibroblasts. We compared the expression of cytoskeletal proteins in cultured ovine cardiac fibroblasts derived from infarcted (ID) and noninfarcted ovine myocardium (NID) and the levels of expression of the natriuretic peptide receptors (NPR)-A and NPR-B in response to treatment with transforming growth factor (TGF)-beta1 and/or platelet-derived growth factor (PDGF). Transformation of cultured cardiac fibroblasts to myofibroblasts, as indicated by alpha-smooth muscle actin and vimentin expression, was independent of the presence of TGF-beta1, PDGF, or cell origin. ID fibroblasts had higher basal levels than NID fibroblasts of NPR-A (ID: 58.0 +/- 32.2 arbitrary density units, NID: undetectable), NPR-B (ID: 780 +/- 155, NID: 330 +/- 38 arbitrary density units) and collagen I (ID: 17.2 +/- 0.5, NID: 10.5 +/- 1.7 pg mRNA/mug total RNA, P0.05) but lower levels of alpha-SMa expression (ID: 50.2 +/- 7.9, NID: 76.9 +/- 3.2 fluorescence units, P0.05). NPR-A mRNA in ID fibroblasts showed a rapid fourfold increase in response to TGF-beta1 and/or PDGF at 4 and 2 h, respectively, followed by a profound decline; in NID cells, NPR-A mRNA was undetectable. In ID fibroblasts, cytokines reduced NPR-B mRNA below control levels; in NID fibroblasts, TGF-beta1 and PDGF elicited prompt increments in expression: a fourfold increase with TGF-beta1 at 8 h and a twofold increase with PDGF at 4 h (P0.05). In summary, transformation of cardiac fibroblasts to myofibroblasts in culture is independent of cytokine treatment. Moreover, whether the cultured cardiac fibroblasts are from infarct tissue is a major determinant of NPR expression levels and cytokine responses, even after four to five passages.

Whilst the tissue distribution and range of biological actions reported for apelin suggest a role for the peptide in pressure/volume homeostasis, conflicting reports make the precise role unclear. Furthermore, few integrated studies have been performed and there are no reports of bioactivity of apelin in a large animal model. Accordingly, we have examined the haemodynamic, hormonal and renal effects of apelin in ten normal conscious sheep. Apelin (1 mg i.v. bolus) induced a biphasic haemo-dynamic response characterised by an acute fall in arterial pressure and a rise in heart rate followed immediately by a rise in arterial pressure and a fall in heart rate. The secondary hypertensive phase was associated with a fall in cardiac output (P=0.015) and significant rises in calculated total peripheral resistance (CTPR) (PP=0.031). Electrocardiogram changes were also observed in four of ten sheep, most notably varying degrees of atrioventricular block. Apelin also induced significant rises in plasma arginine vasopressin (P=0.009), adrenocorticotrophin (P=0.012), aldosterone (P=0.001), cortisol (P=0.014), atrial (P=0.036) and brain (PP=0.003) and cyclic AMP (P=0.002) levels with no effect on renal indices. In conclusion, high dose administration of apelin to normal conscious sheep induces a significant biphasic response in arterial pressure and heart rate associated with rises in RAP and CTPR and a fall in cardiac output. Apelin also increases circulating levels of a number of vasoactive hormones. Taken together, these results suggest a potential role for apelin in pressure/volume homeostasis.

Although urotensin II (UII) has been reported to circulate in human plasma and be raised in cardiovascular disorders, little, if any, information is available regarding the source of plasma UII. Accordingly, we have performed trans-organ arteriovenous sampling for measurement of UII concentration in anesthetized sheep. Plasma UII levels were measured in the low picomolar range in normal sheep and arterial plasma levels rose steadily with increasing time of anesthesia. Significant arteriovenous gradients were observed across the heart (36%), liver (40%) and kidney (44%). This is the first report to identify the heart, liver and kidney as sources of UII in the circulation.

In sheep with HF (heart failure), Ucn1 (urocortin 1) decreases total peripheral resistance and left atrial pressure, and increases cardiac output in association with attenuation of vasopressor hormone systems and enhancement of renal function. In a previous study, we demonstrated in the first human studies that infusion of Ucn1 elevates corticotropin (‘ACTH’), cortisol and ANP (atrial natriuretic peptide), and suppresses the hunger-inducing hormone ghrelin in normal subjects. In the present study, we examined the effects of Ucn1 on pituitary, adrenal and cardiovascular systems in the first Ucn1 infusion study in human HF. In human HF, it is proposed that Ucn1 would augment corticotropin and cortisol release, suppress ghrelin and reproduce the cardiorenal effects seen in animals with HF. On day 3 of a controlled metabolic diet, we studied eight male volunteers with stable HF (ejection fraction

Aims To investigate the subacute effects of a sustained intravenous infusion of urocortin-I (Ucn-I) in experimental heart failure (HF). Methods and results In eight sheep with pacing-induced HF, a 4-day infusion of Ucn-I (0.3 µg/kg/h) induced prompt (30 min) and sustained (4-day) increases in cardiac output (CO, Day 4: 1.8±0.2 vs. 2.3±0.2 L/min, P

Adrenomedullin (AM) may play a role in the pathophysiology of heart failure. Plasma levels of AM are raised in cardiovascular disease in proportion to severity of cardiac dysfunction, and plasma AM levels measured in acute myocardial infarction and heart failure are a useful prognostic indicator of outcome. AM administration in both experimental and human heart failure induces a beneficial spectrum of biological action including reduced arterial and atrial pressures, improved cardiac output, inhibition of plasma aldosterone and preservation or augmentation of urinary sodium excretion. Combining AM administration with either angiotensin-converting enzyme inhibition or neutral endopeptidase inhibition results in augmentation of the hemodynamic and renal effects of the individual treatments. Manipulating the AM system may prove beneficial as an adjunctive therapeutic strategy in cardiac disease.

Blockade of AngII (angiotensin II) and ET (endothelin)-1, established and potential therapeutic strategies respectively, for heart failure, may have an adverse effect on the cardiac secretion of the natriuretic peptides, hormones with actions beneficial in this disease. The present study investigates the roles of AngII and ET-1 in regulating the stretch-induced release of the natriuretic peptides during the development of heart failure. On seven separate days, eight sheep underwent incremental left ventricular pacing (155, 190 and 225 beats/min for 90 min each) with concurrent infusions of a vehicle control, AngII, ET-1, AngII+ET-1, losartan [AT1 (AngII type 1) receptor antagonist], bosentan (ETA/ETB receptor antagonist) or losartan+bosentan. Pacing-induced rises in LAP (left atrial pressure) were amplified by the simultaneous administration of separate AngII and ET-1, and attenuated following blockade of the peptides, with maximum effects observed during combined treatments. Although these changes in atrial pressure were paralleled by concomitant alterations in circulating levels of both ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide), the plasma natriuretic peptide/atrial pressure relationship tended to be augmented by AngII and ET-1 and diminished by their blockade. A significant difference was demonstrated between the enhanced plasma BNP response to increasing LAP during combined AngII+ET-1 administration and decreased response during losartan+bosentan treatment (P