Ultrastructural features of ethanol-induced cardiomyopathy in turkey poults

Chronic effects of ethanol on cultured myocardial cells: ultrastructural and morphometric studies

Ultrastructural alterations of the myocardium due to chronic ethanol exposure were investigated using an in vitro system-mouse ventricular myocardial cells in a monolayer culture, which were spontaneously and synchronously contracting-by chronic exposure to 12.5, 50, and 200 mM ethanol for up to 21 days. Morphometric analyses revealed that exposure to 12.5 mM ethanol for 14 days induced an increase in the number of residual bodies, which are lysosomes containing electron-dense, amorphous materials. Some cells exposed to 50 mM ethanol for 14 days contained an accumulation of glycogen granules, increasing in inverse proportion to the mitochondrial volume. The volumetric proportion of myofibrils on day 14 decreased as the ethanol dose became lower, and was in proportion to large and giant mitochondria within the limits of three ethanol groups. Dose-dependent increases in the size and volumetric proportion of mitochondria were observed after the 14-day exposure; at a low dose (12.5 mM) mitochondria of usual size tended to increase, whereas at a high dose (200 mM) giant mitochondria increased. Coincidentally with this mitochondrial increase or gigantism, all ethanol groups showed higher beat rates than the control. Consequently, it is most likely that chronic 14-day exposures to these three ethanol doses remodel the cellular function of the in vitro myocardium in different ways; the 200-mM dose induced mitochondrial hypertrophy, an adaptive response to switch myocardial energy metabolism over to some special one; the 50-mM dose was a boundary dose; and the 12.5-mM dose mostly mimicked the chronic in vivo administration of ethanol and induced slightly degenerative alterations-increased residual bodies and lysosomes, decreased myofibrils and lowered mitochondrial respiratory function.

Experimental heart muscle damage in alcohol feeding is associated with increased amounts of reduced- and unreduced-acetaldehyde and malondialdehyde-acetaldehyde protein adducts

Chronic and excessive alcohol consumption induces defined myocardial lesions characterized by impaired structural, mechanical and biochemical features. The pathogenic mechanisms are unknown, although it is possible that protein adduct formation by reactive metabolites of ethanol may be a contributory process. Hitherto, this has only been tested with respect to antibodies against reduced-acetaldehyde protein adducts in clinical studies, despite the fact that during alcohol toxicity the formation of reduced-acetaldehyde, unreduced-acetaldehyde, malondialdehyde, malondialdehyde-acetaldehyde and hydroxyethyl protein adducts have been reported in non-cardiac tissues. It was our hypothesis that the heart is particularly sensitive to the formation of protein adducts in alcohol toxicity.To test this hypothesis, we analysed hearts from rats fed nutritionally complete liquid diets containing ethanol as 35% of total calories for 6 weeks, using the Lieber-DeCarli pair-feeding protocol. Control rats were treated identically and fed the same diet in which ethanol was replaced by isocaloric glucose. At the end of the feeding period, the hearts were dissected and ventricular muscle analysed. After 6 weeks' ethanol feeding, ELISA analysis showed increased amounts of reduced-acetaldehyde protein adducts (p < 0.01) unreduced-acetaldehyde (p < 0.01) and malondialdehyde-acetaldehyde (p= 0.01) protein adducts. However, malondialdehyde and alpha-hydroxyethyl-protein adducts were not significantly increased in hearts of ethanol-fed rats compared to pair-fed control (p > 0.1 in both instances). This is the first report of acetaldehyde adduct formation in alcoholic cardiomyopathy. This suggests that either immune process may develop or functional impairment of affected proteins may occur.

Isolated rat cardiomyocytes as an experimental model for studying acute cardiotoxicity of cyclosporin A

The acute cardiotoxicity of cyclosporin A was studied in isolated cardiac myocytes from adult rats. In an initial series of 7 animals, myocytes were incubated with concentrations of cyclosporin A ranging from 1 microgram/ml to 50 micrograms/ml. Shape changes of untreated cells, cells treated with cyclosporin A and cells treated with the solvent of cyclosporin A, Tween 80/ethanol, were evaluated. After 8 hours and 16 hours, respectively, of incubation 92 +/- 4.3% and 72 +/- 8.7% of the non-treated control cells were still rod-shaped. Cyclosporin A, however, in a concentration of 5 micrograms/ml decreased the number of rod-shaped cells (79 +/- 3.2% at 8 hours and 51 +/- 3.5% at 16 hours) in comparison to the solvent (94 +/- 3.5% at 8 hours and 76 +/- 5.8% at 16 hours, P less than 0.02). This effect became more pronounced with higher concentrations of cyclosporin A. On the other hand, Tween 80/ethanol alone in higher concentrations also led to a reduced number of rod-shaped cells. In a second series of 7 animals using Tween 80/ethanol and methanol as drug vehicles, myocytes were incubated for 16 hours with 15 micrograms/ml of cyclosporin A in a calcium containing medium (1 mM) or a calcium free medium (10(-4) M ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid). The number of remaining rod-shaped cells was higher in the calcium free medium as opposed to the medium containing calcium when the cells were exposed to cyclosporin A. It is concluded that in the applied model cyclosporin A at high concentrations has an acute cardiotoxic effect which in part appears to be calcium related.

The challenge of cardiomyopathy

The combined clinical and pathophysiologic characteristics and diagnostic features as well as current concepts of pathogenesis, therapy and prevention of the principal forms of cardiomyopathy are reviewed. These include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy and specific cardiac muscle disease. Emphasis is placed on recent developments and unresolved questions requiring application of newer techniques of molecular biology and genetics and adult myocyte culturing.

Toxicity of 2-hydrazinoethanol in turkey poults

1. Toxicity of 2-hydrazinoethanol was investigated in turkey poults 2-6 weeks posthatch. 2. Significant depression of body wt was evident at concentrations of the drug as low as 10 ppm. 3. Severe anorexia closely paralleled a highly significant decrease in water intake. 4. A significant increase in the ratio of granulocytes to agranulocytes was seen in poults fed the drug at a dose of 50 ppm. 5. Under the conditions of this experiment, none of the tissues sampled exhibited pathologic changes consistent with drug injury.

Animal models of chronic alcohol ingestion: the liquid diet

A suitable animal model that mimics the effects of chronic alcohol intake in man has long been sought. The ethanol-containing liquid diet, although often finding favour in a variety of experimental studies, has recently been criticised for being nutritionally inadequate. Results of this study indicate liquid diets are capable of maintaining the growth of female, but not male, rats at rates comparable to those of similar animals fed on commercially available rodent pellets or on laboratory-prepared pelleted diets. In addition preliminary data are reported indicating the suitability of this model for inducing tolerance to alcohol.

Ethanol-induced alteration in thiamin status of young turkey poults

The effect of ethanol on thiamin status was determined in the turkey poult, a new animal model for alcohol-induced cardiomyopathy in humans. The poults were given ethanol (4 to 5% v/v) in the drinking water for six weeks post-hatch. This treatment decreased body weights and increased significantly the relative weights of the hearts. Ethanol consumption increased significantly the blood concentrations of pyruvate and lactate, decreased the activity of erythrocyte transketolase (TK), and increased the stimulation of TK activity of thiamin pyrophosphate (TPP) in lyzed blood cells (TPP effect). These findings indicate that ethanol treatment has an adverse effect on the thiamin status of the turkey poult.

Plasma triglyceride levels in ethanol-fed turkey poults

Plasma triglyceride levels were determined in ethanol-fed turkey poults at 24 and 38 days posthatch. Ethanol, fed at concentrations of 4, 4.5 and 5% during the first, second and third weeks, respectively, significantly (P less than or equal to 0.5) elevated plasma triglyceride levels. Significantly (P less than or equal to 0.05) increased levels of plasma triglyceride were maintained with continued feeding of 5% ethanol during the fourth and fifth weeks. A significantly (P less than or equal to 0.01) increased ratio of heart weight to body weight in the ethanol-fed poults confirmed the presence of an ethanol-induced cardiomegaly.

Myocardial levels of calcium, glycogen and triglycerides in ethanol-fed turkey poults treated with allopurinol

Effect of allopurinol treatment on myocardial levels of calcium, glycogen and triglyceride and on plasma levels of triglyceride was evaluated in turkey poults during a period of chronic ethanol consumption and following a period of ethanol abstinence. Allopurinol treatment had no significant effect on myocardial levels of calcium. Allopurinol treatment plus abstinence was slightly more effective than abstinence alone in restoring myocardial levels of glycogen and triglyceride and plasma levels of triglyceride in ethanol-fed poults to that seen in control poults.