Actions of a novel synthetic natriuretic peptide on hemodynamics and ventricular function in the dog

2002 ◽  
Vol 282 (4) ◽  
pp. R993-R998 ◽  
Author(s):  
John G. Lainchbury ◽  
Ondrej Lisy ◽  
John C. Burnett ◽  
Donna M. Meyer ◽  
Margaret M. Redfield

Dendroaspis natriuretic peptide (DNP) is a recently discovered peptide with structural similarity to known natriuretic peptides. DNP has been shown to possess potent renal actions. Our objectives were to define the acute hemodynamic actions of DNP in normal anesthetized dogs and the acute effects of DNP on left ventricular (LV) function in conscious chronically instrumented dogs. In anesthetized dogs, DNP, but not placebo, decreased mean arterial pressure (141 ± 6 to 109 ± 7 mmHg, P < 0.05) and pulmonary capillary wedge pressure (5.8 ± 0.3 to 3.4 ± 0.2 mmHg, P < 0.05). Cardiac output decreased and systemic vascular resistance increased with DNP and placebo. DNP-like immunoreactivity and guanosine 3′,5′-cyclic monophosphate concentration increased without changes in other natriuretic peptides. In conscious dogs, DNP decreased LV end-systolic pressure (120 ± 7 to 102 ± 6 mmHg, P < 0.05) and volume (32 ± 6 to 28 ± 6 ml, P < 0.05) and LV end-diastolic volume (38 ± 5 to 31 ± 4 ml, P < 0.05) but not arterial elastance. LV end-systolic elastance increased (6.1 ± 0.7 to 7.4 ± 0.6 mmHg/ml, P < 0.05), and Tau decreased (31 ± 2 to 27 ± 1 ms, P < 0.05). The effects on hemodynamics, LV function, and second messenger generation suggest synthetic DNP may have a role as a cardiac unloading and lusitropic peptide.

2010 ◽  
Vol 299 (2) ◽  
pp. H492-H501 ◽  
Author(s):  
Li Jianhui ◽  
Nathalie Rosenblatt-Velin ◽  
Noureddine Loukili ◽  
Pal Pacher ◽  
François Feihl ◽  
...  

Acute myocardial dysfunction is a typical manifestation of septic shock. Experimentally, the administration of endotoxin [lipopolysacharride (LPS)] to laboratory animals is frequently used to study such dysfunction. However, a majority of studies used load-dependent indexes of cardiac function [including ejection fraction (EF) and maximal systolic pressure increment (dP/d tmax)], which do not directly explore cardiac inotropism. Therefore, we evaluated the direct effects of LPS on myocardial contractility, using left ventricular (LV) pressure-volume catheters in mice. Male BALB/c mice received an intraperitoneal injection of E. coli LPS (1, 5, 10, or 20 mg/kg). After 2, 6, or 20 h, cardiac function was analyzed in anesthetized, mechanically ventilated mice. All doses of LPS induced a significant drop in LV stroke volume and a trend toward reduced cardiac output after 6 h. Concomitantly, there was a significant decrease of LV preload (LV end-diastolic volume), with no apparent change in LV afterload (evaluated by effective arterial elastance and systemic vascular resistance). Load-dependent indexes of LV function were markedly reduced at 6 h, including EF, stroke work, and dP/d tmax. In contrast, there was no reduction of load-independent indexes of LV contractility, including end-systolic elastance (ejection phase measure of contractility) and the ratio dP/d tmax/end-diastolic volume (isovolumic phase measure of contractility), the latter showing instead a significant increase after 6 h. All changes were transient, returning to baseline values after 20 h. Therefore, the alterations of cardiac function induced by LPS are entirely due to altered loading conditions, but not to reduced contractility, which may instead be slightly increased.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Che Cheng ◽  
Zhi Zhang ◽  
Tiankai Li ◽  
Xiaowei Zhang ◽  
Xiaoqiang Sun ◽  
...  

Background: Natriuretic peptides (NPs) play a crucial role in maintaining cardiovascular homeostasis. NPs stimulate the production and release of cGMP, leading to the vasodilating and natriuretic actions. In heart failure (HF), circulating and cardiac ANP, BNP, and CNP are increased and exhibit a range of actions. However, although they serve as therapeutic agents, their direct cardiac effects in HF are uncertain due to the confounding influence of NPs-produced changes in loading condition on conventional measures of LV function. We test the hypothesis that equal hypotensive 3 NPs may have different inotropic effects on LV contractility and relaxation in HF. Methods: We assessed the cardiac effects of intravenous infusion (20 min) of ANP (2 μg/kg plus 0.5 μg/kg/min), BNP (2 μg/kg plus 0.04 μg/kg/min) and CNP (2 μg/kg plus 0.4 μg/kg/min) on different days in 6 instrumented conscious dogs with pacing-induced HF by using pressure (P)-volume (V) analysis, a load-independent measure of LV contractility. Results: Versus baselines, 3 NPs produced arterial vasodilation with similar and significant decreases in LV end-systolic pressure (10 to 12 mmHg) with relatively unchanged heart rate. ANP caused significant reductions (13%) of E ES (4.2 vs 4.8 mmHg/ml) and M SW (54.6 vs 62.8 mmHg). The time constant of LV relaxation (τ, 45.1 vs 37.6 ms) was lengthened. The LV-arterial coupling, E ES / E A (arterial elastance) (0.57 vs 0.58) was unaltered. The peak mitral flow, dV/dt max was only increased by 7% (178 vs 166 ml/s). With BNP, there were no significant changes in E ES (5.1 vs 4.9 mmHg/ml) and M SW, but E ES /E A was improved 30% (0.74 vs 0.57) due to decreased E A . τ (33.4 vs 37.9 ms) was significantly shortened and dV/dt max increased 15% (189 vs 165 ml/s). In contrast, CNP produced significant increases (~30%) in E ES (6.3 vs 4.8 mmHg/ml) and M SW (80.5 vs 62.4 mmHg) with enhanced increase in E ES /E A (50%, 0.87vs 0.58), but decrease in τ (25%, 28.4 vs 38.1 ms) and significantly greater augmented dV/dt max (25%, 205 vs 164 ml/s). Similar observations of NPs were made at constant heart rate, or after autonomic blockade. Conclusion: In conscious dogs with HF, equal hypotensive ANP, BNP and CNP have negative, no effect, and positive inotropic effects on LV contractility and relaxation, respectively.


1991 ◽  
Vol 261 (1) ◽  
pp. H70-H76 ◽  
Author(s):  
W. C. Little ◽  
C. P. Cheng

We investigated the criteria for the coupling of the left ventricle (LV) and the arterial system to maximize LV stroke work (SW) and the transformation of LV pressure-volume area (PVA) to SW. We studied eight conscious dogs that were instrumented to measure LV pressure and determine LV volume from three ultrasonically determined dimensions. The LV end-systolic pressure (PES)-volume (VES) relation was determined by caval occlusion. Its slope (EES) was compared with the arterial elastance (EA) and determined as PES per stroke volume. At rest, with intact reflexes, EES/EA was 0.96 +/- 0.20 EES/EA was varied over a wide range (0.18-2.59) by the infusion of graded doses of phenylephrine and nitroprusside before and during administration of dobutamine. Maximum LV SW, at constant inotropic state and end-diastolic volume (VED), occurred when EES/EA equaled 0.99 +/- 0.15. At constant VED and contractile state, SW was within 20% of its maximum value when EES/EA was between 0.56 and 2.29. The conversion of LV PVA to SW increased as EES/EA increased. The shape of the observed relations of the SW to EES/EA and SW/PVA to EES/EA was similar to that predicted by the theoretical consideration of LV PES-VES and arterial PES-stroke volume relations. We conclude that the LV and arterial system produce maximum SW at constant VED when EES and EA are equal; however, the relation of SW to EES/EA has a broad plateau. Only when EA greatly exceeds EES does the SW fall substantially. However, the conversion of PVA to SW increases as EES/EA increases. These observations support the utility of analyzing LV-arterial coupling in the pressure-volume plane.


Author(s):  
Stephen P. Wright ◽  
William Spencer Cheyne ◽  
Jinelle C. Gelinas ◽  
Megan I. Harper ◽  
John P. Sasso ◽  
...  

Augmented negative intrathoracic pressures (nITP) and dynamic hyperinflation (DH) are adverse breathing mechanics (ABM) associated with chronic obstructive pulmonary disease that attenuate left ventricular (LV) preload and augment afterload. In COPD, hypertension (elevated systemic arterial load) commonly adds additional afterload to the LV. Combined ABM and hypertension may profoundly challenge ventricular-vascular coupling and attenuate stroke volume (SV), particularly if LV systolic reserve is limited. However, even in the healthy heart, the combined impact of ABM and systemic arterial loading on LV function and ventricular-vascular coupling has not been fully elucidated. Healthy volunteers (10M/9F, 24±3 years) were challenged with Mild (-10cmH2O nITP and 25% DH) and Severe (-20cmH2O nITP and 100% DH) ABM, without and with post-exercise ischemia (PEI) at each severity. LV SV, chamber geometry, and end-systolic elastance (Ees), arterial elastance (Ea), and ventricular-vascular coupling (Ees:Ea) were quantified using echocardiography. Compared to resting Control (58±13mL), SV decreased during Mild ABM (51±13mL), Mild ABM+PEI (51±11mL), Severe ABM (50±12mL), and Severe ABM+PEI (47±11mL) (P<0.001); similar trends were observed for LV end-diastolic volume. The end-diastolic radius of septal curvature increased, indicating direct ventricular interaction, during Severe ABM and Severe ABM+PEI (P<0.001). Compared to Control (1.99±0.41mmHg/mL), Ea increased progressively with Mild ABM (2.21±0.47mmHg/mL) and Severe ABM (2.50±0.56mmHg/mL); at each severity Ea was greater with superimposed PEI (P<0.001). However, well-matched Ees increases occurred, and Ees:Ea was unchanged throughout. ABM pose a challenge to ventricular-vascular coupling that is accentuated by superimposed PEI; however, in healthy younger adults, the LV has substantial systolic reserveto maintain coupling.


2000 ◽  
Vol 278 (1) ◽  
pp. H33-H40 ◽  
Author(s):  
John G. Lainchbury ◽  
John C. Burnett ◽  
Donna Meyer ◽  
Margaret M. Redfield

The effects on myocardial function and loading conditions of clinically relevant doses of the natriuretic peptides (NP) have not been established. The actions of single doses (100 ng ⋅ kg− 1 ⋅ min− 1iv over 30 min) of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) were studied in conscious normal dogs and in dogs with pacing-induced heart failure. All three NP reduced end-diastolic pressure in normal dogs, and ANP and BNP reduced end-diastolic volume. In heart failure ANP and BNP reduced EDP, and ANP reduced EDV. Arterial elastance was unchanged in normal dogs and in dogs with heart failure. ANP increased end-systolic elastance ( E es) in normal dogs, whereas BNP tended to increase E es ( P = 0.06). In dogs with heart failure, no inotropic effect was seen. In normal dogs, all NP reduced the time constant of isovolumic relaxation (τ), and ANP and BNP reduced τ in dogs with heart failure. Increases in plasma cGMP in dogs with heart failure were blunted. The NP reduced preload and enhanced systolic and diastolic function in normal dogs. Effects of ANP and BNP on preload and diastolic function were maintained in heart failure. Lack of negative inotropic effects in heart failure supports the validity of the NP as therapeutic agents.


1993 ◽  
Vol 264 (1) ◽  
pp. H53-H60
Author(s):  
C. P. Cheng ◽  
Y. Igarashi ◽  
H. S. Klopfenstein ◽  
R. J. Applegate ◽  
Z. Shihabi ◽  
...  

We assessed the effect of arginine vasopressin (AVP) on left ventricular (LV) performance in eight conscious dogs. Five minutes after AVP infusion (6 microns.kg-1 x min-1 for 2 min) the plasma AVP was elevated from 3.9 +/- 0.9 to 14.7 +/- 4.6 pg/ml (P < 0.05). With all reflexes intact, AVP caused significant increases in LV end-systolic pressure (P) (112 +/- 8 vs. 122 +/- 7 mmHg, P < 0.05) end-systolic volume (V) (30 +/- 5.8 vs. 38 +/- 7.7 ml, P < 0.05), total systemic resistance (6.2 +/- 1.8 vs. 10.6 +/- 4.0 mmHg.dl-1 x min, P < 0.01) and arterial elastance (Ea) (6.8 +/- 3.0 vs. 8.6 +/- 3.9 mmHg/ml, P < 0.05), while the heart rate (110 +/- 6 vs. 82 +/- 10 beats/min, P < 0.05) and stroke volume (16.5 +/- 4.3 vs. 14.2 +/- 3.9 ml, P < 0.05) were decreased. There was no significant change in the coronary sinus blood flow (82 +/- 19 vs. 78 +/- 22 ml/min, P = not significant). AVP decreased the slopes of LV end-systolic P-V relation (10.7 +/- 1.1 vs. 8.1 +/- 1.9 mmHg/ml, P < 0.05), the maximal first derivative of LV pressure (dP/dtmax)-end-diastolic volume (VED) relation (135.2 +/- 18.7 vs. 63.1 +/- 7.7 mmHg.s-1 x ml-1, P < 0.05), and the stroke work-VED relation (81.1 +/- 4.1 vs. 66.7 +/- 2.8 mmHg, P < 0.05) and shifted the relations to the right, indicating a depression of LV performance. A similar increase in Ea produced by methoxamine did not depress LV performance.(ABSTRACT TRUNCATED AT 250 WORDS)


1999 ◽  
Vol 277 (5) ◽  
pp. H1906-H1913 ◽  
Author(s):  
Bo Yang ◽  
Douglas F. Larson ◽  
Ronald Watson

Our study compared left ventricular (LV) function between senescent and young adult mice through in situ pressure-volume loop analysis. Two groups of mice ( n = 9 each), 6-mo-old and 16-mo-old (senescent) mice, were anesthetized with urethan and α-chloralose, and their LV were instrumented with a Millar 1.4-Fr conductance micromanometer catheter for the acquisition of the pressure-volume loops. The senescent mice had a significantly decreased contractile function related to load-dependent parameters, including stroke volume index, ejection fraction, cardiac output index, stroke work index, and maximum derivative of change in systolic pressure over time. The load-independent parameters, preload recruitable stroke work and the slope (end-systolic volume elastance) of the end-systolic pressure-volume relationship, were significantly decreased in the senescent mice. Heart rate and arterial elastance were not different between the two groups; however, the ventricular-to-vascular coupling ratio (ratio of elastance of artery to end-systolic volume elastance) was increased by threefold in the senescent mice ( P < 0.001). Thus there were significant decreases in contractile function in the senescent mouse heart that appeared to be related to reduced mechanical efficiency but not related to arterial elastance.


2004 ◽  
Vol 96 (3) ◽  
pp. 917-922 ◽  
Author(s):  
Israel Belenkie ◽  
Rozsa Sas ◽  
Jamie Mitchell ◽  
Eldon R. Smith ◽  
John V. Tyberg

During acute pulmonary hypertension, both the pericardium and the right ventricle (RV) constrain left ventricular (LV) filling; therefore, pericardiotomy should improve LV function. LV, RV, and pericardial pressures and RV and LV dimensions and LV stroke volume (SV) were measured in six anesthetized dogs. The pericardium was closed, the chest was left open, and the lungs were held away from the heart. Data were collected at baseline, during pulmonary artery constriction (PAC), and after pericardiotomy with PAC maintained. PAC decreased SV by one-half. RV diameter increased, and septum-to-LV free wall diameter and LV area (our index of LV end-diastolic volume) decreased. Compared with during PAC, pericardiotomy increased LV area and SV increased 35%. LV and RV compliance (pressure-dimension relations) and LV contractility (stroke work-LV area relations) were unchanged. Although series interaction accounts for much of the decreased cardiac output during acute pulmonary hypertension, pericardial constraint and leftward septal shift are also important. Pericardiotomy can improve LV function in the absence of other sources of external constraint to LV filling.


1999 ◽  
Vol 91 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Stefan G. De Hert ◽  
Thierry C. Gillebert ◽  
Pieter W. Ten Broecke ◽  
Adriaan C. Moulijn

Background Load-dependent impairment of left ventricular (LV) function was observed after leg elevation in a subgroup of coronary surgery patients. The present study investigated underlying mechanisms by comparing hemodynamic effects of an increase in LV systolic pressures with leg elevation to effects of a similar increase in systolic pressures with phenylephrine. Methods The study was performed in patients undergoing elective coronary surgery prior to cardiopulmonary bypass. High-fidelity LV pressure tracings (n = 25) and conductance LV volume data (n = 10) were obtained consecutively during leg elevation and after phenylephrine administration (5 microg/kg). Results Leg elevation resulted in a homogeneous increase in end-diastolic volume. The change in stroke volume (SV), stroke work (SW) and dP/dtmax was variable, with an increase in some patients but no change or a decrease in other patients. For a matched increase in systolic pressures, phenylephrine increased SW and dP/dtmax in all patients with no change in SV. Load dependence of relaxation (slope R of the tau-end-systolic pressure relation) was inversely related for changes in SV, SW, and dP/dtmax with leg elevation but not with phenylephrine. Conclusions The different effects of leg elevation and phenylephrine suggest that the observed decrease in SV, SW, and dP/dtmax with leg elevation in some patients could not be attributed to an impaired contractile response to increased systolic LV pressures. Instead, load-dependent impairment of LV function after leg elevation appeared related to a deficient length-dependent regulation of myocardial function.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Che Ping Cheng ◽  
Hiroshi Hasegawa ◽  
Atsushi Morimoto ◽  
Heng-Jie Cheng ◽  
William C Little

Background: In heart failure (HF), the impaired left ventricular (LV) arterial coupling and diastolic dysfunction present at rest are exacerbated during exercise (Ex). C-type natriuretic peptide (CNP), the third member of the natriuretic peptide family produced by the vascular endothelium and heart is elevated in HF. However, its functional effects are unclear. We tested the hypotheses that CNP with vasodilating, natriuretic, and lusitropic actions may prevent this abnormal Ex response after HF. Methods: We assessed the effects of CNP on LV functional performance at rest and during submaximum Ex (3.5-5.5 mph for 6-8 min) in 10 instrumented dogs with pacing-induced HF. Since CNP mediated its biological actions via cGMP, we also measured plasma cGMP levels in response to CNP infusion at rest before and after HF. Results: CNP (2 μg/kg plus 0.4 μg/kg/min, iv, 20 min) caused a similar increase in cGMP levels before (7.2±3.8 to 24.7±4.9 pmol/ml) and after HF (20.2±4.4 to 71.6±5.0 pmol/ml). After HF, at rest, CNP reduced LV end-systolic pressure (P ES , CNP: 93 vs Baseline: 104 mmHg), arterial elastance (E A , 8.3 vs 11.7 mmHg/ml) and end-diastolic pressure (P ED , 37.2 vs 42.4 mmHg) (p<0.05). The peak mitral flow (dV/dt max , 201±51 vs 160±34ml/sec) was also increased due to decreased minimum LVP (LVP min , 17.1 vs 23.8 mmHg) and the time constant of LV relaxation (t, 40±4 vs 48±6 msec) (p<0.05). In addition, the slope of LV end-systolic pressure-volume relations (E ES ) was increased (5.6±0.7 vs 4.2±0.9 mmHg/ml). The LV-arterial coupling, quantified as E ES /E A , was improved (0.69±0.22 vs 0.48±0.16) (p<0.05). The beneficial effects persisted during Ex. At matched levels of Ex, treatment with CNP, Ex-induced significantly less increases in P ES (ΔP= 3.4±0.5 vs 7.4±0.8 mmHg), mean LAP (ΔP= -3.1±2.2 vs 3.6±2.9 mmHg), and LVP min (ΔP= -3.6±1.4 vs 1.4±1.2 mmHg) (p<0.05). With CNP, t was much shortened (Δ= -0.8±4.0 vs 2.8±3.2 ms), and the peak mitral flow was further augmented (ΔdV/dt max , 75±20 vs 43±12 ml/sec) (p<0.05). Conclusion: After HF, the generation of cGMP in response to CNP is not blunted. CNP produces arterial vasodilatation and augments LV contraction, relaxation, diastolic filling and LV arterial coupling, thus improving LV performance, both at rest and during Ex after HF.


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