Atrial natriuretic peptide transcription, storage, and release in rats with myocardial infarction

1987 ◽  
Vol 253 (6) ◽  
pp. H1449-H1455 ◽  
Author(s):  
R. E. Mendez ◽  
J. M. Pfeffer ◽  
F. V. Ortola ◽  
K. D. Bloch ◽  
S. Anderson ◽  
...  

To study the role of atrial natriuretic peptide (ANP) in chronic heart failure, ANP synthesis, storage, and release were examined by measuring atrial ANP messenger ribonucleic acid (mRNA) levels and atrial and plasma ANP concentrations in rats with myocardial infarction produced by coronary artery ligation. Three groups were defined as the following: 1) controls, sham-operated, or operated, but noninfarcted; 2) moderate infarcts, involving 5-30% of the left ventricular circumference; and 3) large infarcts (greater than or equal to 30%). In addition, to determine a possible modulation by dietary Na intake on ANP levels in heart failure, plasma immunoreactive ANP (iANP) levels were measured in rats with and without infarcts given low, regular, or high Na intake for 2 wk, by which time all groups were in neutral balance. Plasma iANP levels varied directly with increasing infarct and atrial sizes, irrespective of Na intake. In contrast, atrial ANP concentration varied inversely with increasing infarct size. The ANP mRNA content index, a measure of total atrial ANP mRNA, was significantly increased in rats with large infarcts compared with control rats. These results indicate that in rats with myocardial infarction, the severity of left ventricular dysfunction, as inferred from infarct size, but not chronic Na intake, is the primary determinant of the extent of activation of the ANP system. Elevated circulating ANP levels are maintained through enhanced atrial synthesis and release. ANP may thus play an important role in the hemodynamic and renal adaptations to chronic heart failure.

Life Sciences ◽  
1987 ◽  
Vol 40 (20) ◽  
pp. 2025-2030 ◽  
Author(s):  
Richard W. Lee ◽  
Richard G. Gay ◽  
Cassandra Moffett ◽  
David G. Johnson ◽  
Steven Goldman

1988 ◽  
Vol 74 (6) ◽  
pp. 659-663 ◽  
Author(s):  
G. P. Hodsman ◽  
R. W. Harrison ◽  
E. Sumithran ◽  
C. I. Johnston

1. The relationship between plasma atrial natriuretic peptide (ANP) and body sodium was determined in rats 1 month after myocardial infarction induced by coronary artery ligation. After operation rats received a normal or a low salt diet, and total exchangeable body sodium was measured sequentially. 2. Rats with infarction receiving a normal salt intake did not retain sodium when compared with sham-operated controls. Rats receiving a low salt diet had a 10% decrease in body sodium (P < 0.01). The decrease was the same in rats with infarction as in controls. 3. Plasma ANP was similar in control rats irrespective of salt status. Plasma ANP levels were markedly elevated in rats with infarction irrespective of salt status (P < 0.01). 4. The rise in plasma ANP was correlated with cardiac hypertrophy and infarct size in animals fed both normal and low salt diets. However, there was no relationship between plasma ANP and exchangeable body sodium. 5. These results suggest that in this model of heart failure plasma ANP is raised by increased left atrial stretch in proportion to the severity of left ventricular dysfunction. In contrast, plasma ANP concentrations do not appear to be elevated as a consequence of increased right atrial pressure caused by sodium retention and expanded extracellular volume.


1989 ◽  
Vol 256 (2) ◽  
pp. H533-H538 ◽  
Author(s):  
M. Kohzuki ◽  
G. P. Hodsman ◽  
C. I. Johnston

The natriuretic, diuretic, and hypotensive effects of atrial natriuretic peptide (ANP) were examined in rats 4 wk after myocardial infarction induced by left coronary artery ligation. Synthetic rat ANP (fragment 1-28) was infused intravenously in doses of 0.1, 0.3, and 1.0 micrograms.kg-1.min-1 for 30 min. There was a significant decrease in systolic blood pressure in controls and rats with infarction, although only in control rats was there a significant decrease in diastolic blood pressure. Changes in systolic and diastolic blood pressure were attenuated in rats with infarction compared with controls (P less than 0.01). The diuretic and natriuretic effects of ANP were observed in both groups of rats, but the effects were significantly less in rats with infarction (P less than 0.01). The ANP infusion did not induce significant changes in heart rate or hematocrit in controls or rats with infarction. The results indicate that rats with chronic left heart failure are less sensitive to the natriuretic, diuretic, and hypotensive effects of ANP when compared with controls. The attenuated renal response to ANP may contribute to the impaired sodium and water excretion in chronic heart failure, although other mechanisms are involved.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Deddo Moertl ◽  
Martin Huelsmann ◽  
Joachim Struck ◽  
Andreas Gleiss ◽  
Alexandra Hammer ◽  
...  

Background: Although natriuretic peptides are increasingly used for the management of chronic heart failure (CHF), there are sparse comparative data. Therefore, we compared the importance of influencing factors, the ability to detect left ventricular systolic dysfunction, and the prognostic power of midregional pro-atrial natriuretic peptide (MR-proANP), B-type natriuretic peptide (BNP), and aminoterminal pro-B-type natriuretic peptide (NT-proBNP) in patients with chronic heart failure. Methods and Results: MR-proANP, using a new assay directed at the midregion of aminoterminal-proANP, was compared with BNP and NT-proBNP, using conventional assays, in 797 patients with CHF. All three natriuretic peptides were independently influenced by left ventricular ejection fraction (LVEF), glomerular filtration rate (GFR), and the presence of ankle edema. Area under receiver-operator characteristic curves for detection of an LVEF <40% were similar between MR-proANP (0.799 [0.753– 0.844]) and BNP (0.803 [0.757– 0.849]), and NT-proBNP (0.730 [0.681– 0.778]. During a median observation time of 68 months, 492 patients died. In multiple Cox regression analysis each natriuretic peptide was the strongest prognostic parameter among various clinical variables, but proportion of explained variation showed that NT-proANP was a significantly stronger predictor of death than NT-proBNP and BNP (Figure ). Conclusions: Despite similarities in influencing factors and detection of reduced LVEF, MR-proANP outperformed BNP and NT-proBNP in the prediction of death. A new assay technology and the high biological stability of MR-proANP are potential explanations for these findings.


2004 ◽  
Vol 286 (1) ◽  
pp. H381-H387 ◽  
Author(s):  
Ling Chen ◽  
Chang Xun Chen ◽  
Xiaohong Tracey Gan ◽  
Norbert Beier ◽  
Wolfgang Scholz ◽  
...  

Sodium/hydrogen exchange (NHE) inhibitors show promise as potential therapeutic agents for the treatment of heart failure, but it is not known whether they can reverse the maladaptive remodeling that results in heart failure. We sought to determine the effect of the NHE-1-specific inhibitor EMD-87580 (EMD) on heart failure produced by myocardial infarction in the rat and to assess whether up to 4 wk of treatment delay results in beneficial effects. Male Sprague-Dawley rats were subjected to coronary artery ligation (or a sham procedure) and followed for up to 3 mo, at which time hypertrophy and hemodynamics were determined. EMD was provided in the diet, and treatment commenced immediately or 2–4 wk after ligation. EMD significantly reduced hemodynamic abnormalities, including the elevation in left ventricular end-diastolic pressure, and diminished the loss of systolic function with all treatment protocols. Left ventricular dilatation and hypertrophy, as assessed by heart weight, cell size, and atrial natriuretic peptide (ANP) expression, were similarly reversed to sham or near-sham levels. In addition, the increased plasma ANP and pro-ANP values were reversed to levels not significantly different from sham. Surprisingly, virtually all beneficial effects were identical with all treatment protocols. These effects were observed in the absence of infarct size reduction or blood pressure-lowering effects. Our results suggest that NHE-1 inhibition attenuates and reverses postinfarction remodeling and heart failure with a treatment delay of up to 4 wk after infarction. The effect is independent of infarct size or afterload reduction, indicating a direct effect on the myocardium.


2004 ◽  
Vol 96 (4) ◽  
pp. 1306-1311 ◽  
Author(s):  
Jarkko Magga ◽  
Mikko Puhakka ◽  
Seppo Hietakorpi ◽  
Kari Punnonen ◽  
Paavo Uusimaa ◽  
...  

Experimental data suggest that atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) act locally as antifibrotic factors in heart. We investigated the interrelationships of natriuretic peptides and collagen markers in 93 patients receiving thrombolytic treatment for their first acute myocardial infarction (AMI). Collagen formation following AMI, evaluated as serum levels of amino terminal propeptide of type III procollagen, correlated with NH2-terminal proANP ( r = 0.45, P < 0.001), BNP ( r = 0.55, P < 0.001) and NH2-terminal proBNP ( r = 0.50, P < 0.01) on day 4 after thrombolysis. Levels of intact amino terminal propeptide of type I procollagen decreased by 34% ( P < 0.001), and levels of carboxy terminal cross-linked telopeptide of type I collagen (ICTP) increased by 65% ( P < 0.001). ICTP levels correlated with NH2-terminal proBNP ( r = 0.25, P < 0.05) and BNP ( r = 0.28, P < 0.05) on day 4. Our results suggest that ANP and BNP may act as regulators of collagen scar formation and left ventricular remodeling after AMI in humans. Furthermore, degradation of type I collagen is increased after AMI and may be regulated by BNP.


2011 ◽  
Vol 57 (9) ◽  
pp. 1327-1330 ◽  
Author(s):  
Ingrid Hunter ◽  
Urban Alehagen ◽  
Ulf Dahlström ◽  
Jens F Rehfeld ◽  
Dan L Crimmins ◽  
...  

BACKGROUND The N-terminal fragment of cardiac-derived pro–B-type natriuretic peptide is a glycosylated polypeptide. It is unknown whether N-terminal pro–atrial natriuretic peptide (proANP) fragments are also covalently modified. We therefore evaluated the clinical performance of 2 distinctly different proANP assays on clinical outcome. METHODS We examined 474 elderly patients with symptoms of heart failure presenting in a primary healthcare setting. Samples were analyzed with an automated immunoluminometric midregion proANP (MR-proANP) assay and a new processing-independent assay (PIA) developed in our laboratory. The results were compared with Bland–Altman plots, and clinical performance was assessed by generating ROC curves for different clinical outcomes. RESULTS Despite linear regression results indicating a good correlation (r = 0.85; P &lt; 0.0001), the PIA measured considerably more proANP than the MR-proANP assay (mean difference, 663 pmol/L; SD, 478 pmol/L). In contrast, the clinical performances of the 2 assays [as assessed by the area under the ROC curve (AUC)] in detecting left ventricular dysfunction were similar [proANP PIA, 0.71 (95% CI, 0.63–0.79); MR-proANP assay, 0.74 (95% CI, 0.66–0.81); P = 0.32]. The prognostic ability to report cardiovascular mortality during a 10-year follow-up revealed AUC values of 0.66 (95% CI, 0.60–0.71) for the proANP PIA and 0.69 (95% CI, 0.63–0.74) for the MR-proANP assay (P = 0.08, for comparing the 2 assays). CONCLUSIONS Our data suggest that N-terminal proANP fragments in patient plasma differ from the calibrator peptides used but that the difference does not affect ROC curves in an elderly cohort of patients with mild to moderate heart failure. We suggest that human N-terminal proANP fragments can be covalently modified.


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