HEMODYNAMIC AND METABOLIC EFFECTS OF CHRONIC ALCOHOLISM IN MAN

Quantifying the contribution of alcohol to cardiomyopathy: A systematic review

Alcohol has a direct toxic impact on the heart, and while there is an ICD code for alcoholic cardiomyopathy, the burden of alcohol-attributable cardiomyopathy is not clear. For the usual estimation of this burden via population-attributable fractions, one would need to determine the risk relationships, i.e., average risk associated with different dimensions of alcohol exposure. The most important among these risk relationships is the dose-response relationship with different levels of average alcohol consumption. To establish risk relationships, we systematically searched for all studies on dose-response relationships, directly and indirectly, via reviews. The results did not permit computation of pooled estimates through meta-analyses. There were clear indications that heavy drinking (≥80 g per day) over several years was linked to high risk of cardiomyopathy, with greater lifetime exposure of alcohol linked to higher risks. Some studies indicated potential effects of patterns of drinking as well. As such, the global quantification of alcohol-attributable cardiomyopathy will have to rely on other methods than those used conventionally.

¹H and ³¹P NMR lipidome of ethanol-induced fatty liver

BACKGROUND

 Hepatic steatosis (fatty liver), an early and reversible stage of alcoholic liver disease, is characterized by triglyceride deposition in hepatocytes, which can advance to steatohepatitis, fibrosis, cirrhosis, and ultimately to hepatocellular carcinoma. In the present work, we studied altered plasma and hepatic lipid metabolome (lipidome) to understand the mechanisms and lipid pattern of early-stage alcohol-induced-fatty liver.

METHODS

 Male Fischer 344 rats were fed 5% alcohol in a Lieber-DeCarli diet. Control rats were pair-fed an equivalent amount of maltose-dextrin. After 1 month, animals were killed and plasma collected. Livers were excised for morphological, immunohistochemical, and biochemical studies. The lipids from plasma and livers were extracted with methyl-tert-butyl ether and analyzed by 750/800 MHz proton nuclear magnetic resonance (¹H NMR) and phosphorus (³¹P) NMR spectroscopy on a 600 MHz spectrometer. The NMR data were then subjected to multivariate statistical analysis.

RESULTS

 Hematoxylin and Eosin and Oil Red O stained liver sections showed significant fatty infiltration. Immunohistochemical analysis of liver sections from ethanol-fed rats showed no inflammation (absence of CD3 positive cells) or oxidative stress (absence of malondialdehyde reactivity or 4-hydroxynonenal positive staining). Cluster analysis and principal component analysis of ¹H NMR data of lipid extracts of both plasma and livers showed a significant difference in the lipid metabolome of ethanol-fed versus control rats. ³¹P NMR data of liver lipid extracts showed significant changes in phospholipids similar to ¹H NMR data. ¹H NMR data of plasma and liver reflected several changes, while comparison of ¹H NMR and ³¹P NMR data offered a correlation among the phospholipids.

CONCLUSIONS

 Our results show that alcohol consumption alters metabolism of cholesterol, triglycerides, and phospholipids that could contribute to the development of fatty liver. These studies also indicate that fatty liver precedes oxidative stress and inflammation. The similarities observed in plasma and liver lipid profiles offer a potential methodology for detecting early-stage alcohol-induced fatty liver disease by analyzing the plasma lipid profile.

Morphometric and biochemical characteristics of short-term effects of ethanol on rat cardiac muscle

Alcoholism is a very important cause of congestive cardiomyopathy in man. The aim of this study was to examine a short-term effect of ethanol in rat cardiac muscle, using histologic, morphometric and biochemical methods. Experiments were carried out in Wistar male albino rats, divided into two groups: the control group consisting of eight animals receiving tap water, and the experimental group comprising eight animals received ethyl alcohol for ten days, in a single daily dose of 3 g ethanol/kg body weight, per os, using esophageal intubation. The mean volume weighted nuclear volume of cardiac myocytes was estimated by point sampled intercept method, by objective x 100. The mean cubed nuclear intercept length was multiplied by pi and divided by 3. For biochemical analysis, a 10% water tissue homogenate from the left ventricle was made. In the experimental group, the mean volume-weighted nuclear volume (15.08 +/- 5.20 microm3) was significantly lower than in the control group (51.32 +/- 7.83 microm3) (p < 0.001). The treatment of experimental animals with ethanol caused significant increase of aldolase (p < 0.0001) and aspartate transaminase (p < 0.05) activity in the rat cardiac tissue; at the same time, the enzyme activity of creatine phosphokinase, alanine transaminase and alkaline phosphatase were not changed in the experimental group compared to the control values. The amount of the glucose in the cardiac muscle was greater in the experimental group compared to the control animals. Our results suggest that there is depression of cardiomyocyte nuclei in experimental animals treated with ethanol. Alcohol intake results in the loss of Krebs cycle enzymes and as a consequence there is greater utilization of fatty acids for energy production.

Combined effects of caffeine and alcohol on hemodynamics and coronary artery blood flow in dogs

Alcohol intake is often followed by coffee drinking because of the universal acceptance of its sobering effect. Such effects were found inconsistent on motor functions. However, it is common belief that caffeine will antagonize the intoxicating effects of alcohol. The independent actions of caffeine and alcohol are well documented, but combined effects of short-term administration are unknown. This experimental work was designed to study the effects due to short-term administration of caffeine and alcohol on the cardiovascular system. In phase I, 30 experiments were performed in our laboratories to study the dose-response curves of both the drugs. In phases II and III, 15 dogs were subjected to 30 experiments. In phase II, caffeine, 5 mg/kg, was given i.v., followed by ethanol, 400 mg/kg i.v., and in phase III, sequence of drug administration was reversed to study the effects on hemodynamics and coronary artery blood flow. Caffeine did not show significant changes in all the cardiovascular parameters, and ethanol administration caused nonsignificant increase in heart rate, mean arterial pressure, left ventricular systolic pressure, and left ventricular (LV) mechanical work and decrease in the maximal rate of first derivative of LV pressure, stroke volume, and systemic vascular resistance. Left ventricular end-diastolic, pulmonary artery mean and right atrial pressures, pulmonary vascular resistance, myocardial oxygen consumption, and as coronary flow reserve increased as compared with controls. Combined caffeine and alcohol had synergistic effects, but when the order of drug administration was reversed (i.e., alcohol was followed by caffeine), the effect was antagonistic.

Combined effects of alcohol and nicotine on cardiovascular performance in a canine model

Alcohol and tobacco consumption are correlated. Smokers consume more alcohol than do nonsmokers, and alcohol consumers smoke more than do teetotalers. The independent effects of alcohol and nicotine on the cardiovascular system are well documented, but combined effects of short-term administration are unknown. This experimental work was designed to study the effects due to short-term administration of alcohol and nicotine on cardiovascular system. In phase I, 30 experiments were performed to study the dose-response curve of both the drugs. In phases II and III, 15 dogs were subjected to 30 experiments. In phase II, ethanol, 400 mg/kg, was given i.v., followed by nicotine 50 microg/kg, i.v., and in phase III, sequence of drug administration was reversed to study the effects on hemodynamics and coronary artery blood flow. The dose-response curve established the i.v. dose of ethanol, 400 mg/kg, and nicotine, 50 microg/kg. Ethanol administration caused a nonsignificant increase in heart rate (HR), mean arterial pressure (MAP), left ventricular systolic pressure (LVS), and left ventricular mechanical work (LVMW), and a decrease in maximal rate of increase of LV pressure per second (dP/dt), stroke volume (SV), and systemic vascular resistance (SVR). Left ventricular end-diastolic pressure (LVEDP), pulmonary artery mean pressure (PAM), right atrial pressure (RAP), pulmonary vascular resistance (PVR), myocardial oxygen consumption (MVO2), and average peak velocity of coronary blood flow (APV) had mild significant increases as compared with controls. Nicotine significantly increased heart rate, mean arterial pressures, LVEDP, and pulmonary artery, pulmonary capillary wedge, and right atrial pressures. Nicotine increased dP/dt (2,062-3,188; p < 0.006) and decreased APV (9 to 8; p < 0.03). Combined ethanol followed by nicotine had synergistic increase in HR, SD, MAP, LVS, LVEDP, pulmonary pressures, CO, SV, dP/dt (2,184 > 5,206; p < 0.005), MVO2, and LVMW. However, the excitatory effects of nicotine were attenuated when ethanol was administered after nicotine (dP/dt, reduced from 2,058 to 1,653; p < 0.04, and APV increased from 10 to 12; p < 0.02). We conclude that ethanol increased APV but had nonsignificant effects on the hemodynamics, whereas nicotine reduced the APV and had significant excitatory responses. In combination (i.v.), ethanol + nicotine produced significant synergistic excitatory effects. On the other hand, the nicotine + ethanol combination increased APV and caused attenuation of the excitatory effects of nicotine in dogs.

Chronic ethanol consumption and withdrawal affects mitochondrial benzodiazepine receptors in rat brain and peripheral organs

Ethanol administration to rats for 30 days resulted in a significant decrease (-28%; P < 0.05) in the density of mitochondrial benzodiazepine receptors (MBR) in the olfactory bulb. The reduction in [3H]PK 11195 binding persisted 24 hr after cessation of alcohol and had returned to normal values when measured 4 days later. Alterations were confined to this brain region and were not detected in the cerebral cortex, cerebellum or hippocampus. [3H]PK 11195 binding was elevated in the liver (100%; P < 0.01), heart (43%; P < 0.01) and testis (27%; P < 0.05) 30 days following ethanol consumption and this persisted for 1 and 4 days after abrupt withdrawal. A transitory decrease (-20%; P < 0.05) in MBR density was observed in the adrenal gland following 30 days of alcohol ingestion, but disappeared during withdrawal. The alterations in these receptors may be relevant to the cellular damage or dysfunction induced by chronic exposure to ethanol.

Alcohol-induced congestive cardiomyopathy in adult turkeys: effects on myocardial antioxidant defence systems

The effects of chronic intake of dietary alcohol upon left ventricular function, activities of myocardial antioxidant enzymes, reduced glutathione (GSH) content and lipoperoxidation (measured as the formation of diene conjugates and lipid-soluble fluorescence) were studied in adult domestic Nicholas turkeys. The non-invasive evaluation of left ventricular function by echocardiography revealed an impaired contractile function (the calculated fractional shortening values were 31.1 +/- 4.1% in the alcoholic group and 38.8 +/- 4.4% in the controls) and dilatation of the heart in the alcoholic birds. The changes in the non-invasive parameters of the left ventricle indicate that the adult Nicholas turkey developed congestive cardiomyopathy secondary to the ingestion of ethanol. In the hearts of normal adult turkeys, high GSH content (2.39 +/- 0.25 mumol/g wet weight) and superoxide dismutase activity were found, as compared to other animals, indicating the relatively higher development of antioxidant defence systems. Compared to the controls, significant increases were noted for all the antioxidant enzymes investigated (superoxide dismutase, catalase and glutathione peroxidase) and a moderately significant decrease in the GSH content was found in the left ventricle of alcoholic birds. The changes in GSH concentration and antioxidant enzyme activities might indirectly indicate some involvement of free radicals in the pathogenesis of ethanol-induced myocardial lesion. However, the levels of in vivo lipoperoxidation in the alcoholic birds did not significantly vary from those of control turkeys. Based on these findings, it appears that the reactive oxygen radicals may play a less important role in the pathogenesis of alcohol-induced cardiomyopathy in turkeys--probably due to the higher development of myocardial antioxidant defence systems.

Relation between alcohol intake, myocardial enzyme activity, and myocardial function in dilated cardiomyopathy. Evidence for the concept of alcohol induced heart muscle disease

Detailed drinking histories were taken in 38 patients in whom dilated cardiomyopathy was diagnosed by cardiac catheterisation and left ventricular biopsy. On the basis of the drinking history twenty patients were classified as being in an abstinent or light drinking group and eighteen patients as being in a heavy drinking group (daily alcohol intake in excess of 80 g or cumulative lifetime intake exceeding 250 kg). Activities of myocardial creatine kinase, lactate dehydrogenase, alpha hydroxybutyric dehydrogenase, malic dehydrogenase, and aspartate amino-transferase were all higher in the heavy drinkers and myocardial enzyme activity correlated with cumulative lifetime alcohol intake, maximum daily intake, and recent daily intake. Activities of creatine kinase, alpha hydroxybutyric dehydrogenase, and malic dehydrogenase correlated with ejection fraction, irrespective of the alcohol intake of the patient. These findings were not altered by exclusion of patients with hypertension. The results indicate that among patients with dilated cardiomyopathy there is a group characterised by a high alcohol intake and raised myocardial tissue enzymes which supports the concept of alcoholic heart muscle disease as a distinct entity.

Ethanol toxicity in primary cultures of rat myocardial cells

The potential cardiotoxicity of ethanol (EtOH) was evaluated in primary cultures of rat myocardial cells. EtOH cardiotoxicity was assessed in the cells on the basis of cell morphology, lactate dehydrogenase (LDH) leakage, succinate dehydrogenase (SDH) activity, and beating rates. Cells were treated with EtOH at concentrations of 600, 800, and 1000 mg% for duration of 1, 4, and 24 h and then evaluated for cardiotoxicity. Vacuole formation occurred 1 h after exposure to EtOH at 800 and 1000 mg%; by 4 h, cytosolic granular material appeared in these cells. Exposure for 24 h to all concentrations of EtOH resulted in vacuole, granule, and pseudopod formation and loss of cross-striations. Significant LDH leakage occurred at 1 h and 4 h with 800 and 1000 mg% EtOH. LDH release was significantly increased after 24 h with all concentrations. SDH activity was significantly depressed after 24 h with all concentrations of EtOH. Beating rates were altered as early as 1 h after exposure to 800 and 1000 mg% EtOH. After 24 h, those cells exposed to the highest concentrations of EtOH were not beating at all. These data suggest that primary myocardial cell cultures may be used to assess the in vitro cardiotoxicity of EtOH to the myocardial cell.

Ultrastructural features of ethanol-induced cardiomyopathy in turkey poults

Alcoholic cardiomyopathy, characterized by cardiac hypertrophy, was induced in young turkey poults with 5% ethanol. Ultrastructural features included accumulation of glycogen, swollen mitochondria, myofibrillar lysis, increased number of lysosomes, dilated sarcoplasmic reticulum and dense myofibers. Similarity of these alterations to those described in human alcoholic cardiomyopathy confirms the usefulness of the turkey poult as an animal model for this disease syndrome.

Biochemical mechanisms responsible for alcohol-associated myocardiopathy

An overview of alcohol metabolism is presented followed by a discussion of the unique pathways for the metabolism of ethanol by the heart. The evidence for cardiac metabolic injury produced as a result of ethanol metabolism is then presented. Such injury involves the mitochondria, contractile proteins, and alterations in calcium fluxes and storage.

The cardiomyopathies: a review of terminology, pathology and pathogenesis

A classification of the cardiomyopathies based on functional and morphological features is outlined, a detailed account of the pathology of each type is presented and possible pathogenetic mechanisms are reviewed. Myocarditis and its relationship to cardiomyopathy is considered and the main morphological and aetiological factors are presented.

Alcohol and the heart

Acute alcohol ingestion can lead to alterations of either mechanical function or electrophysiologic properties of the heart, whereas chronic consumption can lead to progressive cardiac dysfunction and congestive cardiomyopathy. On the other hand, alcohol appears to have a protective effect for coronary artery disease when consumed in low amounts, although prophylactic use of alcohol is not recommended.

The effect of abstinence on left ventricular performance in asymptomatic chronic alcoholics

Twelve asymptomatic men who were chronic alcoholics (42.3 +/- 10.7 years, mean age +/- 1 SD) underwent supine bicycle exercise and gated cardiac blood pool imaging 4-7 days after alcohol withdrawal and then again 32-65 days after abstinence (42.2 +/- 15.0 days). Workloads and exercise stages were identical during both exercise studies. Rest and exercise heart rates, blood pressures, cardiac outputs, double products, and systemic vascular resistances were similar in both studies. Ejection fraction (EF) was higher after abstinence at peak exercise (0.68 +/- 0.07 vs. 0.61 +/- 0.08 P less than 0.05); end-systolic volume (ESV) was smaller at rest and at peak exercise after abstinence (P less than 0.05). During the first exercise study, 6 of 12 (50%) subjects did not increase their EF by 0.05 units and 4 of 12 (33%) had no EF increase after abstinence. Even the original "normal" responders had greater rest and exercise EFs after abstinence. In the first exercise study end diastolic volume (EDV) rose during exercise (P less than 0.05) while ESV did not change. After abstinence, EDV did not change during exercise, while ESV declined (P less than 0.05). These results show that latent cardiac dysfunction exists in asymptomatic chronic alcoholics, which is partially although not completely resolved by abstinence of brief periods.

Role of acetaldehyde and acetate in the development of ethanol-induced cardiac lipidosis, studied in isolated perfused rat hearts

Isolated perfused rat hearts were used to study the effects of ethanol, acetaldehyde, and acetate on the cellular redox state and fatty acid metabolism in the myocardium. Ethanol had negligible effects on the cellular redox state but at high concentrations depressed the contractile activity and thereby secondarily the oxygen consumption. Acetaldehyde in concentrations below 50 microM had negligible effects on the redox state of the mitochondrial free NAD+/NADH couple, as studied by surface fluorometry of flavins and nicotinamide nucleotides. A reduction of NAD+ was observed with concentrations between 50 and 500 microM, while in the range of 0.5-1 mM the effect was biphasic, i.e., an initial reduction was followed by oxidation concomitantly with an increase in heart rate and peak systolic pressure. Acetate in millimolar concentrations caused in the coronary flow. A mitochondrial acetaldehyde dehydrogenase was revealed in the myocardium, having an apparent Km of 1.1 microM for acetaldehyde. Acetaldehyde in 50-microM concentration had no major effects on the uptake, oxidation, or lipid incorporation of oleate in the myocardium. Acetate in concentrations less than 2 mM did not affect the uptake of oleate into the myocardium, but did inhibit is oxidation and enhance its incorporation into tissue lipids in a dose-dependent manner. 2 mM acetate caused a 91% increase in oleate incorporation into tissue lipids over 30 min. The data can be interpreted as showing that acetaldehyde and acetate, the metabolites of ethanol, have metabolic effects on the myocardium, but only those of acetate are significant in concentrations encountered during ethanol oxidation in vivo. It is probable that acetate is involved in the development of ethanol-induced myocardial lipidosis, inhibiting the oxidation of fatty acids, and channelling them into the esterification pathway.

Prevalence of clinically occult cardiomyopathy in chronic alcoholism

The mean absolute heart weight and mean heart weight to body weight ratio of a group of 43 alcoholics, screened from 1,970 consecutive autopsy reports at the Detroit General Hospital by selecting alcoholics with only ethyl alcohol abuse as an etiology of heart disease, are compared to those of a group of similarity selected age-matched nonalcoholic controls. None of the alcoholics was clinically suspected of having had cardiomyopathy. The statistically significant increased mean absolute heart weight and heart weight to body weight ratio of the alcoholic group reflected the presence of subclinical alcoholic cardiomyopathy. In addition, several of the patients in the alcoholic group displayed gross and microscopic cardiac pathologic changes consistent with alcoholic cardiomyopathy occurring in the absence of cardiomegaly.

Echocardiographic abnormalities in chronic alcoholics with and without overt congestive heart failure

To assess the type and prevalence of cardiac abnormalities in heavy drinkers with and without overt congestive heart failure, M mode echocardiography was performed in 11 symptomatic chronic alcoholics with dilated (congestive) cardiomyopathy and in 22 asymptomatic chronic alcoholics. Echocardiographic data in both groups were adjusted for age and body surface area using previously derived regression equations. All 11 symptomatic patients had a significantly decreased left ventricular percent fractional shortening (mean 14 percent, normal range 28 to 44) along with significant increases in left ventricular systolic and diastolic dimensions (mean increases of 105 and 48 percent above normal, respectively), left atrial dimension (mean increase 21 percent) and estimated left ventricular mass (mean increase 105 percent). Among the 22 asymptomatic patients, 15 (68 percent) demonstrated significant increases in at least one of the following echocardiographic variables: left ventricular mass, left ventricular dimensions, septal and left ventricular wall thicknesses, and left atrial dimension. Asymptomatic patients could be classified into two subgroups: (1) those with a left ventricular diastolic dimension less than 10 percent above the normal predicted value and an increased left ventricular wall thickness to radius ratio (mean increase 16 percent above normal) and upper normal percent fractional shortening, and (2) those with a left ventricular diastolic dimension 10 to 24 percent above normal and a slightly subnormal thickness to radius ratio and lower normal percent fractional shortening. Echocardiographic abnormalities in asymptomatic chronic alcoholics did not correlate with the presence or absence of auscultatory abnormalities on physical examination and appear to reflect an earlier stage in the spectrum of alcoholic disease before the development of dilated cardiomyopathy.

Cardiac metabolsim: its contributions to alcoholic heart disease and myocardial failure

Changes in cardiac metabolism in myocardial failure and after alcohol ingestion are discussed. The main effect of alcohol ingestion is loss of cardiac contractility. Since heart muscle does not contain alcohol dehydrogenase, its toxicity is probably the result of a direct toxic effect of ethanol and acetaldehyde on the myocardial cell, possibly involving various membrane systems. Alcohol inhibits mitochondrial respiration and the activity of enzymes in the tricarboxylic acid cycle, and its interferes with both mitochondrial calcium uptake and binding. Ethanol profoundly affects myocardial lipid metabolism. Acetaldehyde diminishes myocardial protein synthesis and inhibits Ca++-activated myofibrillar ATPase. In myocardial failure, a series of possibilities may be responsible for the loss of contractility. Excitation-contraction coupling could be disturbed at the level of the sarcolemma, at the sarcoplasmic reticulum, at the mitochondria, and between calcium and the regulatory proteins. Deficiencies in Ca++ delivery systems of excitation-contraction coupling on the myosin ATPase activity could be responsible for the dimunition in cardiac contractility. Mitochondrial function may also be involved, since mitochondria from failing human hearts are defective with respect to respiratory control and calcium accumulation. Under certain conditions, the relationship of mitochondria to calcium sequestration is very important in influencing contractility. The involvement of contractile and regulatory proteins in myocardial failure cannot be excluded.

Chronic alcoholic cardiomyopathy: fact or fiction?

This study was designed to ascertain whether excessive prolonged alcohol intake itself may produce chronic cardiomyopathy. We reasoned that, since alcoholic cardiomyopathy is allegedly a chronic condition, asymptomatic or early symptomatic cases should be found in a large hospitalized alcoholic population. Two groups of patients were studied. The first group consisted of 292 chronic alcoholics whose hospital records were examined for evidence of early cardiomyopathy, according to predetermined criteria. The second group consisted of eight patients who died on the medical service ward and in whom one of the diagnoses listed in the autopsy report was alcoholic cardiomyopathy. In the first group hepatic and neurological complications of alcoholism were frequent; no patient was found to have early cardiomyopathy. In the second group the post-mortem records indicated that all eight patients had other illnesses causing the abnormal findings on which the diagnosis of alcoholic cardiomyopathy was made. We conclude that the concept of chronic alcoholic cardiomyopathy caused by the direct toxic effect of alcohol may not be valid.

Alcoholic heart disease

Alcohol has been suspected for many years of being a cause of heart disease. For a while its role was obscured by its association with beriberi heart disease and, more recently, by the toxic effect of cobalt in beer. Experimental studies, however, have provided convincing evidence of the primary role of alcohol itself. The mode of action is still in dispute. In the absence of specific findings, the diagnosis is made chiefly by exclusion of other known causes of heart disease and by a history of excessive alcohol intake over a number of years. The usual methods of treatment for the manifestations of heart failure, arrhythmias, and thromboembolic phenomena are important, but total abstinence from alcohol is the single essential factor. The sooner this is instituted, the better is the chance of interrupting the otherwise inexorable course to death.

[Acute lethal alcohol intoxication (author's transl)]

In 14,744 autopsy cases from an 18-year period 92 cases (of which 7 were ruled out because of decomposition were observed in which death was supposed to be due to direct acute alcoholic intoxication. In the police reports 81 persons were designated as chronic alcoholics or abusers of spirits. The blood alcohol level ranged between 2.04 and 4.92 o/oo. The cases studied were divided into two groups, one with low and the other with high lethal alcohol level. Fatty liver and cirrhosis were found with identical frequency in the two groups, whereas cardiac hypertrophy of obscure origin occurred markedly more often in the group with low lethal blood alcohol level. On the basis the possible mechanism of death in the cases with cardiac hypertrophy is discussed. Finally, the relation between the blood and urine alcohol concentrations observed in 72 cases is discussed. On the assumption that the water phase of the blood was 75 per cent of the total blood, death occurred in the persons without cardiac hypertrophy with fairly identical frequency either in the phase of absorption or the phase of elimination, whereas in the persons with cardiac hypertrophy death most often occurred in the phase of absorption. These statements should, however, be taken with some reservation, partly because the water phase of the blood may vary considerably post mortem (60-90 per cent) and partly because the urine alcohol concentration depends on serval variable factors.

The effect of prolonged administration of ethanol on cardiac metabolism and performance in the dog

The effect of prolonged administration of alcohol on mitochondrial function and high-energy phosphate (ATP) of heart muscle was investigated in dogs. Animals were divided into two groups, a control group and a group that received alcohol. In the experimental series, dogs received 400 ml of a 25% solution of alcohol added to the food and drinking water. Measurements were carried out after ethanol had been withheld for 2 days. Total myocardial blood flow, cardiac output, and myocardial O(2) consumption remained at control levels. Measurement of cardiac contractility using the maximal rate of left ventricular pressure rise (dP/dt(max)) showed no change in animals exposed to alcohol. When the afterload of the heart was increased with angiotensin, a slight but not significant decline in cardiac contractility was observed. Activities of various intramitochondrial and extramitochondrial enzymes were measured in both groups. After alcohol administration, the primarily intramitochondrial isocitrate dehydrogenase diminished. ATP in heart muscle of dogs exposed to alcohol declined, and mitochondrial oxygen consumption and respiratory control indices diminished. These observations suggest that the primary lesion leading to alteration of myocardial performance is a biochemical malfunction of the mitochondria, which at this early stage is not reflected in changes in myocardial contractility.

Metabolic effects of ethanol on the rabbit heart

Ethanol in saline solution (15%, v/v) was infused into anesthetized rabbits at a rate of 0.494 ml/min for the first 12 minutes and then at 0.247 ml/min for 108 minutes. Three hours after the infusion, heart triglyceride and lipoprotein lipase were assayed. Oxidation and esterification of fatty acids (palmitate -14 C as an indicator) were assessed by using either tissue homogenates or perfused hearts taken from the rabbits. Oxidation-reduction states of the perfused hearts were examined by measuring the tissue levels of dehydrogenase-linked substrates. The infusion of ethanol resulted in 180% increase in heart triglyceride content, but the infusion of norepinephrine (3 µg/kg/min) did not change the content. No change in plasma free fatty acids and triglyceride or heart lipoprotein lipase activity was detected. Addition of ethanol had little effect on the distribution of palmitate -14 C in the lipids of tissue slices and homogenates. On the other hand, prior infusion of ethanol resulted in depression of 14 CO 2 production (70 and 50%) and enhanced fatty acid esterification into triglyceride (270 and 170%) both in homogenates and perfused hearts. Mitochondrial and cytoplasmic redox states were shifted to more oxidized states by ethanol infusion. It is postulated from these results that an accumulation of triglyceride in the rabbit heart in response to ethanol administration is a result of decreased fatty acid oxidation rather than of increased triglyceride uptake or increased fatty acid synthesis.