Effect of chronic moderate ethanol consumption on heart brain natriuretic peptide

nNOS is involved in cardiac remodeling induced by chronic ethanol consumption

Chronic ethanol consumption has deleterious effects on the cardiovascular system by directly damaging the myocardial structure and/or by neurohormonal activation. Moreover, nitric oxide (NO) derived from neuronal NO synthase (nNOS) seems to be important to balance the harmful effects of ethanol consumption, because it influences several aspects of cardiac physiology and attenuates pathological cardiac remodeling. However, the impact of chronic ethanol consumption on nNOS expression is unknown. We address this subject in the present study by evaluating whether chronic ethanol consumption induces cardiac remodeling and hypertension, and if these changes are associated with alterations in the expression of nNOS. Male Wistar rats were examined after ingesting a 20% alcohol solution for 6 months. Blood alcohol concentration and brain natriuretic peptide (BNP) levels were measured. The cardiac remodeling was assessed by histomorphometric analysis and the nNOS expression was evaluated by immunofluorescence and western blot analysis. Our results show that chronic ethanol consumption induces cardiac remodeling, namely thinning of left ventricular wall, cardiomyocyte hypertrophy and increased fibrosis, and elevations of arterial blood pressure. They also show that in rats fed with ethanol for 6 months, the circulating BNP levels had decreased as well as the expression of nNOS in left ventricle cardiomyocytes. These findings suggest that the effects of chronic ethanol consumption on BNP levels and/or on nNOS expression in cardiomyocytes may contribute to aggravate the cardiac remodeling and leads to progression of cardiomyopathy.

Increases in B-type natriuretic peptide after acute mental stress in heart failure patients are associated with alcohol consumption

OBJECTIVE

The aim of this study was to investigate in heart failure (HF) patients whether acute mental stress induces increases in the HF-severity biomarker B-type natriuretic peptide (BNP) and if alcohol consumption is associated with such stress-induced increases.

METHOD

Twenty-one male HF patients and 19 male non-HF controls (M = 56 years, SEM = 2) underwent a 15-minute acute mental stress test combining public speaking and mental arithmetic. Plasma levels of BNP were determined immediately before as well as 2 hours after the stress test. Alcohol consumption was assessed by self-reported number of drinks per month and history of use.

RESULTS

HF patients had higher BNP levels before and after stress, F(1, 38) = 23.42, p < .001, and showed greater stress-induced increases in BNP levels, F(1, 38) = 4.52, p = .04, compared with controls. HF status (beta = .32, p = .015, deltaR(2) = .10) and higher alcohol consumption ((beta = .61, p< .001, deltaR(2) = .37) were independently associated with higher BNP stress increases. Moreover, higher alcohol consumption moderated the greater BNP stress increases in HF patients but not in controls (p = .49, p < .001, delta(2) = .20), although alcohol consumption did not differ between groups.

CONCLUSIONS

For individuals with HF, particularly those who drink moderate to more substantial amounts of alcohol, exposure to acute psychological stress leads to increases in circulating levels of BNP, a biomarker which is associated with increased morbidity and mortality in HF.

[Circadian rhythms and effects of anesthesia on plasma natriuretic peptide levels in rats]

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are circulating hormones secreted predominantly in patients with hypertension or congestive heart failure. To obtain background data on plasma ANP and BNP levels in rats, we investigated the circadian rhythms and effects of anesthesia on these peptides. To determine the circadian rhythms, plasma samples from thirty rats were collected by non-anesthesia (decapitation) at six time points every fourth hour. To determine the effects of anesthesia, plasma samples from thirty-two rats were collected under diethyl ether, pentobarbital or urethane anesthesia. The plasma ANP and BNP levels were determined using a radioimmunoassay. The plasma ANP levels were high from the evening to early morning, while the plasma BNP levels were relatively low at 2:30 AM. The difference in the BNP levels was statistically significant. The plasma BNP levels were relatively high when the rats were anesthetized using urethane. These results suggest that blood collection should be performed between 10:30 AM to 2:30 PM to determine plasma ANP and BNP. The use of pentobarbital is also recommended for toxicological studies in rats.

Ethanol for cardiac ischemia: the role of protein kinase c

The physiological effects of ethanol are dependent upon the amount and duration of consumption. Chronic excessive consumption can lead to diseases such as liver cirrhosis, and cardiac arrhythmias, while chronic moderate consumption can have therapeutic effects on the cardiovascular system. Recently, it has also been observed that acute administration of ethanol to animals prior to an ischemic event provides significant protection to the heart. This review focuses on the different modalities of chronic vs. acute ethanol consumption and discusses recent evidence for a protective effect of acute ethanol exposure and the possible use of ethanol as a therapeutic agent.

Mechanism by which Alcohol and Wine Polyphenols Affect Coronary Heart Disease Risk

The reduction in coronary heart disease (CHD) from moderate alcohol intake may be mediated, in part, by increased fibrinolysis; endothelial cell (EC)-mediated fibrinolysis should decrease acute atherothrombotic consequences (eg, plaque rupture) of myocardial infarction (MI). We have shown that alcohol and individual polyphenols modulate EC fibrinolytic protein (t-PA, u-PA, PAI-1, u-PAR and Annexin-II) expression at the cellular, molecular, and gene levels to sustain increased fibrinolytic activity. Herein we describe the sequence of molecular events by which EC t-PA expression is increased through common activation of p38 MAPK signaling. Up-regulation of t-PA gene transcription, through specific alcohol and polyphenol transcription factor binding sites in the t-PA promoter, results in increased in vitro fibrinolysis and in vivo clot lytic activity (using real-time fluorescence [Fl] imaging of Cy5.5-labeled fibrin clot lysis in a mouse model). Fl-labeled fibrin clots injected into untreated C56Bl/6 wild-type control mice are lysed in approximately 2 hours and clot lytic rates significantly increased in mice treated with either alcohol, catechins, or quercetin (4-6 weeks). Fl-labeled clot lysis in ApoE knock-out mice (atherosclerosis model) showed impaired in vivo clot lysis that was "normalized" to wild-type control levels by treatment with alcohol, catechin, or quercetin for 6 to 8 weeks.

Intracerebroventricular infusion of angiotensin II increases water and ethanol intake in rats

The influence of prolonged ingestion of ethanol on stimulation of water or ethanol intake by intracerebroventricular infusion of ANG II was evaluated in rats. Animals were maintained for 5-6 mo with either 10% ethanol solution or water as their only source of fluid. In both groups of rats, infusion of ANG II caused a large increase in water intake (7-fold) and a lesser increase in 10% ethanol intake (2-fold). The effect of ANG II on the volume of ethanol solution ingested, however, was inversely related to the concentration of the ethanol solution. As the concentration of ethanol solution was decreased, frequency and duration of drinking bouts increased. The intake of sweetened 10% ethanol solution or commercially produced wine during infusion of ANG II was similar to the intake of 10% ethanol and not related to taste preference. In conclusion, chronic consumption of ethanol solution did not appear to adversely effect ANG II stimulation of water intake. The intake of ethanol solution during infusion of ANG II was inhibited by a direct effect of ingested ethanol and/or by indirect effect from metabolized ethanol.

Altered regulation of natriuretic peptides in the rat heart by prenatal exposure to morphine

1. Both endogenous and exogenous opioids modulate blood pressure and cardiac function by stimulating cardiac synthesis of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP). Since morphine crosses the placental barrier, it could alter the ANF-BNP system in the fetal heart. The aim of this study was to characterize cardiac natriuretic peptides in normal rat development and in rats prenatally exposed to morphine. 2. Female rats received either saline or morphine (10 or 20 mg kg-1 day-1) via osmotic minipumps during gestation. The effects of this treatment were investigated in offspring at 1, 4 and 22 days of age. 3. During maturation, atrial ANF and ANF mRNA increased by 3-fold from birth to 3 weeks of age, but BNP and BNP mRNA tended to decrease. In the ventricles, both ANF and BNP content decreased at 3 weeks after birth, from 25.11 +/- 3.6 to 0.81 +/- 0.1 ng (mg protein)-1 (P < 0.001), and from 3.36 +/- 0.33 to 0.19 +/- 0.01 ng (mg protein)-1 (P < 0.001), respectively. However, whereas ventricular ANF mRNA decreased, BNP mRNA levels did not change during maturation. Prenatal exposure to morphine significantly increased ANF content in the left atria of 22-day-old rats, and in the right atria of 1-, 4- and 22-day-old rats compared with age-matched saline controls. In contrast, prenatal exposure to 20 mg kg-1 day-1 morphine significantly inhibited BNP and BNP mRNA in the ventricles at all ages studied. 4. These observations suggest that alterations in mRNA synthesis or stability and/or post-translational processing of ANF and BNP occur in the heart during maturation, and that prenatal exposure to morphine alters cardiac production, and possibly release, of both peptides.

Alterations in brain levels of atrial and C-type natriuretic peptides after chronic moderate ethanol consumption in spontaneously hypertensive rats

Atrial (ANP) and C-type (CNP) natriuretic peptides have been found in brain regions associated with fluid homeostasis and blood pressure. Since chronic moderate ethanol consumption has been shown to prevent the age-dependent increase in blood pressure in experimental animals, the objective of the present studies was to investigate the effect of ethanol (20% (v/v) for 8 months) on the total content and concentration of ANP and CNP in the brain of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Ethanol increased the content and concentration of both ANP and CNP in the hypothalamus, pons and medulla of SHR rats. In contrast, in the WKY rats ethanol had no effect on the levels of ANP in any of the brain regions studies, but enhanced the concentration of CNP in the hypothalamus and medulla. Thus, ethanol induced changes in the content of natriuretic peptides in distinct brain regions associated with control of cardiovascular activity. Such changes may be partially responsible for the effect of chronic moderate ethanol consumption on blood pressure.