Depressed selenium and vitamin E levels in an alcoholic population. Possible relationship to hepatic injury through increased lipid peroxidation

Antioxidant effects of Se-glutathione peroxidase in alcoholic liver disease

Oxidative damage induced by ethanol and its metabolites is one of the factors that fuels the development of alcoholic liver disease (ALD). Selenium (Se) is an effective cofactor for glutathione peroxidase (GPx), and has antioxidant effects that improve ALD. In patients with ALD, ethanol-induced oxidative damage inhibits the synthesis of related Se-containing proteins such as: selenoprotein P (Sepp1), albumin (ALB), and GPx in the liver, thus decreasing the overall Se level in patients. Both Se deficiency and excess can affect the expression of GPx, resulting in damage to the antioxidant defense system. This damage enhances oxidative stress by increasing the levels of reactive oxygen species (ROS) in the body, which aggravates the inflammatory response, lipid metabolism disorder, and lipid peroxidation and worsens ALD symptoms. A cascade of oxidative damages caused by ALD will deplete selenium deposition in the body, stimulate the expression of Gpx1, Sepp1, and Gpx4, and thus mobilize systemic selenoproteins, which can restore GPx activity in the hepatocytes of ALD patients, reduce the levels of reactive oxygen species and alleviate oxidative stress, the inflammatory response, lipid metabolism disorder, and lipid peroxidation, thus helping to mitigate ALD. This review provides a reference for future ALD studies that evaluate the regulation of Se levels and contributes to studies on the potential pathological mechanisms of Se imbalance in ALD.

The Role of Micronutrients in the Pathogenesis of Alcohol-Related Liver Disease

AIMS

Chronic alcohol consumption may result in liver injury and chronic liver disease, but other factors are likely to influence disease progression. Malnutrition, specifically micronutrient deficiency, is frequently associated with both alcohol use disorder and chronic liver disease. We hypothesize that micronutrient deficiencies may affect the progression of liver disease in this population.

METHODS

Systematic integrative review of the medical literature; electronic search of MEDLINE 1950-2021; studies investigating role of any micronutrient in the acceleration of alcohol-related liver injury in humans or animals. Studies which specifically related to alcoholic hepatitis were excluded. Outcomes were extracted and recorded in tabulated form and discussed narratively.

RESULTS

We identified 46 studies investigating the role of micronutrient deficiencies in the pathogenesis of alcohol-related liver disease. Specific micronutrients which were identified included folic acid or related B vitamins (n = 9 studies), Vitamin D (n = 9 studies), magnesium (n = 8 studies), zinc (n = 8 studies) and selenium (n = 12 including one systematic review). Observational evidence suggests a potential role of magnesium deficiency in accelerating alcohol-related liver injury with weak or negative evidence for other micronutrients.

CONCLUSIONS

Magnesium deficiency may increase the risk of alcohol-related liver injury and adverse liver outcomes. However, currently, there is insufficient evidence to support magnesium supplementation except for clinically relevant magnesium deficiency. Long-term prospective cohort studies assessing the impact of micronutrients on liver disease progression in patients with alcohol use disorder are lacking and may help determine whether there is a causal role for micronutrient deficiencies in alcohol-related liver injury.

Magnesium, Calcium, Potassium, Sodium, Phosphorus, Selenium, Zinc, and Chromium Levels in Alcohol Use Disorder: A Review

Macronutrients and trace elements are important components of living tissues that have different metabolic properties and functions. Trace elements participate in the regulation of immunity through humoral and cellular mechanisms, nerve conduction, muscle spasms, membrane potential regulation as well as mitochondrial activity and enzymatic reactions. Excessive alcohol consumption disrupts the concentrations of crucial trace elements, also increasing the risk of enhanced oxidative stress and alcohol-related liver diseases. In this review, we present the status of selected macroelements and trace elements in the serum and plasma of people chronically consuming alcohol. Such knowledge helps to understand the mechanisms of chronic alcohol-use disorder and to progress and prevent withdrawal effects, also improving treatment strategies.

The importance of nutrition in aiding recovery from substance use disorders: A review

BACKGROUND

Nutrition is a prerequisite for health; yet, there is no special nutritional assessment or guidance for drug and alcohol dependent individuals, despite the fact that their food consumption is often very limited, risking malnutrition. Further, the premise is examined that malnutrition may promote drug seeking and impede recovery from substance use disorders (SUD).

METHOD

A narrative review addressed the relationship between substance use disorders and nutrition, including evidence for malnutrition, as well as their impact on metabolism and appetite regulation. The implications of the biopsychology of addiction and appetite for understanding the role of nutrition in SUD were also considered.

RESULTS

The literature overwhelmingly finds that subjects with alcohol use disorder (AUD) and drug use disorder (DUD) typically suffer from nutrient deficiencies. These nutrient deficiencies may be complicit in the alcoholic myopathy, osteopenia and osteoporosis, and mood disorders including anxiety and depression, observed in AUD and DUD. These same individuals have also been found to have altered body composition and altered hormonal metabolic regulators. Additionally, brain processes fundamental for survival are stimulated both by food, particularly sweet foods, and by substances of abuse, with evidence supporting confusion (addiction transfer) when recovering from SUD between cravings for a substance and craving for food.

CONCLUSION

Poor nutritional status in AUD and DUD severely impacts their physical and psychological health, which may impede their ability to resist substances of abuse and recover their health. This review contributes to a better understanding of interventions that could best support individuals with substance use disorders.

Vitamin status in patients with acute pancreatitis

The serum levels of 6 vitamins were prospectively evaluated in 20 patients with acute biliary pancreatitis and in 20 patients with acute alcoholic pancreatitis. Twenty healthy subjects acted as controls. There were no statistically significant differences in the levels of vitamin B12 and D among the groups. Patients with alcoholic pancreatitis had significantly lower levels of vitamins A, E (p < 0.01) and C (p < 0.001) than those of the control group. Plasma levels of vitamin K were decreased or undetectable in 6 patients with biliary and 3 with alcoholic pancreatitis. The pathophysiological and clinical implications of this abnormal vitamin status in patients with acute pancreatitis are unknown. Nevertheless, multi-vitamin supplementation seems justified, especially in patients affected by alcoholic pancreatitis. Vitamin K should be administered in both types of pancreatitis when blood coagulation tests are disturbed.

Metabolism of ethanol and associated hepatotoxicity

Over the last three decades, direct hepatotoxic effects of ethanol were established, some of which were linked to redox changes produced by NADH generated via the alcohol dehydrogenase (ADH) pathway and shown to affect the metabolism of lipids, carbohydrates, proteins, and purines. It was also determined that ethanol can be oxidized by a microsomal ethanol oxidizing system (MEOS) involving a specific cytochrome P-450; this newly discovered ethanol-inducible cytochrome P-450 (P-450 IIEi) contributes to ethanol metabolism, tolerance, energy wastage (with associated weight loss), and the selective hepatic perivenular toxicity of various xenobiotics. Their activation by P-450IIEi now provides an understanding of the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, over-the-counter analgesics, and chemical carcinogens. P-450 induction also explains depletion (and toxicity) of nutritional factors such as vitamin A. As a consequence, treatment with vitamin A and other nutritional factors is beneficial, but must take into account a narrowed therapeutic window in alcoholics who have increased needs for nutrients and also display an enhanced susceptibility to some of their adverse effects. Acetaldehyde (the metabolite produced from ethanol by either ADH or MEOS) impairs hepatic oxygen utilization and forms protein adducts, resulting in antibody production, enzyme inactivation, and decreased DNA repair. It also stimulates collagen production by the vitamin A storing cells (lipocytes) and myofibroblasts, and causes glutathione depletion. Supplementation with S-adenosyl-L-methionine partly corrects the depletion and associated mitochondrial injury, whereas administration of polyunsaturated lecithin opposes the fibrosis. Thus, at the cellular level, the classic dichotomy between the nutritional and toxic effects of ethanol has now been bridged. The understanding of how the ensuing injury eventually results in irreversible scarring or cirrhosis may provide us with improved modalities for treatment and prevention.

Selenium deficiency is associated with insulin resistance in patients with hepatitis C virus-related chronic liver disease

The relationship between selenium (Se) deficiency and insulin resistance has not much been established in persistent hepatitis C virus (HCV) infection, although Se deficiency is often observed in patients with liver cirrhosis. We hypothesized that the decreased serum Se levels were associated with the severity of hepatic fibrosis or insulin resistance in patients with HCV-related chronic liver disease (CLD). To test the hypothesis, 52 patients with HCV-related CLD including chronic hepatitis and liver cirrhosis were enrolled in this study. The severity of hepatic fibrosis was divided into 4 categories (F(1) through F(4)) according to the new Inuyama classification. Insulin resistance was defined by the homeostasis model for assessment of insulin resistance value. Serum Se levels significantly declined in proportion to the severity of hepatic fibrosis and were positively correlated with serum albumin (r = 0.372, P = .0065) and zinc (r = 0.403, P = .0081) concentrations. Serum Se levels were also linked to glutathione peroxidase activities in the sera of the enrolled patients (r = 0.374, P = .0148). By contrast, serum Se levels were inversely correlated with the homeostasis model for assessment of insulin resistance values (r = -0.304, P = .0338). However, serum Se levels were independent of HCV genotype and loads of HCV-RNA. These findings suggest that Se deficiency was associated with the severity of hepatic fibrosis in patients with HCV-related CLD and that Se deficiency was likely to be one of the factors contributing to insulin resistance in those patients.

Antioxidants as therapeutic agents for liver disease

Oxidative stress is commonly associated with a number of liver diseases and is thought to play a role in the pathogenesis of chronic hepatitis C, alcoholic liver disease, non-alcoholic steatohepatitis (NASH), haemochromatosis and Wilson's disease. Antioxidant therapy has thus been considered to have the possibility of beneficial effects in the management of these liver diseases. Despite this promise, antioxidants have produced mixed results in a number of clinical trials of efficacy. This review summarizes the results of clinical trials of antioxidants as sole or adjuvant therapy of chronic hepatitis C, alcoholic liver disease and non-alcoholic steatohepatitis (NASH). Overall, the most promising results to date are for vitamin E therapy of NASH but some encouraging results have been obtained with antioxidant therapy of acute alcoholic hepatitis as well. Despite evidence for small reductions of serum alanine aminotransferase, there is as yet no convincing evidence that antioxidant therapy itself is beneficial to patients with chronic hepatitis C. Problems such as small sample size, short follow up duration, inadequate endpoints, failure to demonstrate tissue delivery and antioxidant efficacy, and heterogeneous nature of the 'antioxidant' compounds used have complicated interpretation of results of the clinical studies. These limitations and their implications for future trial design are discussed.

Selenium and preeclampsia: A global perspective

Preeclampsia is a complex multisystem disorder of pregnancy where oxidative stress plays an important aetiological role. The role of selenium in the synthesis of endogenous antioxidants is well documented, and a significant reduction in selenium has been reported in preeclamptic women. The objective of this study was to map global selenium status and preeclampsia incidence. This study identified peer reviewed journal articles reporting national preeclampsia incidence (%) and matched these with reported values of selenium intake and plasma/serum selenium concentrations (μg/L). Matched data were obtained for 45 regions, reporting 6456,570 births, spanning Europe, Asia, Australasia, Africa, North and South America. Increasing plasma selenium concentration was found to be correlated with a reduction in preeclampsia incidence (Pearson's r=-0.604, P<0.0001). Countries with a reported serum/plasma selenium level of ⩾95μg/L were considered selenium sufficient and a significant reduction in preeclampsia incidence for countries above this value (P=0.0007) was noted. Significant reductions in preeclampsia incidence were found to coincide with increases in plasma/serum selenium concentration in the New Zealand (P=0.0003) and Finland (0.0028) populations following Government intervention. This study supports the hypothesis that selenium supplementation may be beneficial in reducing oxidative stress in women at risk of preeclampsia.

The role of liver biopsy in detection of hepatic oxidative stress

The goal of the current paper is to explore the role of liver biopsy as a tool in detection of hepatic oxidative stress, with brief notes on different types of free radicals, antioxidants, hepatic and blood oxidative stress, and lipid peroxidation. Hepatic oxidative stress was investigated for many years in human and animals, but most of the studies performed in animals were concerned with studying oxidative status in the liver tissues after slaughtering or euthanasia. However, in human medicine, a large number of studies were implemented to investigate the status of antioxidants in liver biopsy specimens. Similar studies are required in animals, as the changes in hepatic antioxidants and formation of lipid peroxide give a good idea about the condition of the liver. On the other hand, hepatic disease may present without significant effect on blood oxidative status, and, consequently, the best way to detect the status of hepatic oxidants and antioxidants is through measuring in liver biopsy. Measuring antioxidants status directly in the liver tissues gives an accurate estimation about the condition of the liver, permits the diagnosis of hepatic dysfunction, and helps to determine the degree of deterioration in the hepatic cells.

Nrf2 and antioxidant defense against CYP2E1 toxicity

The transcription factor Nrf2 regulates the expression of important cytoprotective enzymes. Induction of CYP2E1 is one of the central pathways by which ethanol generates oxidative stress. CYP2E1 can be induced by ethanol and several low molecular mass chemicals such as pyrazole. This review discusses biochemical and toxicological effects of CYP2E1 and the effects of Nrf2 in modulating these actions of CYP2E1. Besides ethanol, CYP2E1 metabolizes and activates many other toxicologic important compounds. One approach to try to understand the basic effects and actions of CYP2E1 was to establish HepG2 cell lines that constitutively express human CYP2E1. Ethanol, polyunsaturated fatty acids and iron were toxic to the HepG2 cells, which express CYP2E1 (E47 cells) but not control C34HepG2 cells, which do not express CYP2E1. Toxicity was associated with enhanced oxidant stress and could be prevented by antioxidants and potentiated if glutathione was removed. The E47 cells had higher glutathione levels and a twofold increase in catalase, cytosolic and microsomal glutathione transferase, and heme oxygenase-1 than control HepG2 cells due to activation of their respective genes. These activations were prevented by antioxidants, suggesting that reactive oxygen species generated by CYP2E1 were responsible for the upregulation of these antioxidant genes. This upregulation may reflect an adaptive mechanism to remove CYP2E1-derived oxidants. Increases in Nrf2 protein and mRNA were observed in livers of chronic alcohol-fed mice or rats and of pyrzole-treated rats or mice, conditions known to elevate CYP2E1. E47 cells showed increased Nrf2 mRNA and protein expression compared with control HepG2 C34 cells. Upregulation of antioxidant genes in E47 cells is dependent on Nrf2 and is prevented by siRNA-Nrf2. Blocking Nrf2 by siRNA-Nrf2 decreases glutathione and increases reactive oxygen species and lipid peroxidation, resulting in decreased mitochondrial membrane potential and loss of cell viability of E47 cells, but not C34 cells. Nrf2 is activated and levels of Nrf2 protein and mRNA are increased when CYP2E1 is elevated. These results suggest that Nrf2 plays a key role in the adaptive response against increased oxidative stress caused by CYP2E1 in the HepG2 cells. However, it is not clear whether Nrf2 is protective against CYP2E1 toxicity in vivo as pyrazole which elevates CYP2E1 in wild-type mice did not elevate CYP2E1 in Nrf2 knockout mice, although pyrazole produced toxicity in the Nrf2 knockout mice.

Role of oxidative stress in alcohol-induced liver injury

Reactive oxygen species (ROS) are highly reactive molecules that are naturally generated in small amounts during the body's metabolic reactions and can react with and damage complex cellular molecules such as lipids, proteins, or DNA. Acute and chronic ethanol treatments increase the production of ROS, lower cellular antioxidant levels, and enhance oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury. Special emphasis is placed on CYP2E1, which is induced by alcohol and is reactive in metabolizing and activating many hepatotoxins, including ethanol, to reactive products, and in generating ROS.

Occupational exposure to mineral fibres. Biomarkers of oxidative damage and antioxidant defence and associations with DNA damage and repair

In order to study the effect of mineral wool exposure on oxidative DNA damage and lipid peroxidation, an epidemiological study was conducted in a mineral wool factory in Slovakia. Altogether 141 subjects were investigated (21-58 years old), 43 controls (20 men and 23 women: 27 non-smokers, 16 smokers) and 98 exposed (75 men and 23 women: 61 non-smokers, 37 smokers). We found higher malondialdehyde (MDA) levels in the group of all exposed workers (P = 0.025) and in exposed non-smokers (P = 0.003) and a significantly suppressed activity of ceruloplasmin oxidase (P = 0.02, P < 0.02, respectively) and catalase (CAT) (P = 0.04, P = 0.01, respectively) in these groups. The activity of glutathione S-transferase (GST) was affected by exposure to mineral wool; levels were significantly lower in all exposed subjects (P = 0.04), in the exposed non-smokers (P = 0.03) and in exposed men (P < 0.01). Concentrations of vitamin C in plasma and the ferric-reducing activity of plasma (FRAP) were not affected by the mineral wool exposure. There was a significant negative correlation between the activity of glutathione peroxidase (GPX) and MDA in the whole group (P < 0.01) and in the exposed group and between CAT activity and MDA in all subjects (P < 0.01). GST activity correlated inversely with oxidized pyrimidines in lymphocyte DNA, in almost all subgroups. We found significant negative correlations between DNA repair and GPX in all subjects (P = 0.03) as well as in control men (P < 0.03) and between DNA repair and CAT in all control subjects (P < 0.02) and in control men (P < 0.01). Interestingly, we found a positive correlation between DNA repair and MDA in all subjects (P < 0.01) and in all exposed subjects (P < 0.03). The presented results indicate that mineral wool exposure induces an increase in oxidative damage to biomolecules especially in the group of male non-smokers. However, optimal levels of antioxidants could have a protective effect. Biomarkers such as MDA, antioxidant enzymes and antioxidant vitamins measured in blood may be useful biomarkers of oxidative stress and antioxidant protection. We do not recommend FRAP as a marker of antioxidant status as interference from other constituents can provide false or confusing results. Our study supports the idea that there might also be other mechanisms by which antioxidant enzymes (especially GST) protect cells against oxidative DNA damage.

Selenium in global food systems

Food systems need to produce enough of the essential trace element Se to provide regular adult intakes of at least 40 μg/d to support the maximal expression of the Se enzymes, and perhaps as much as 300 μg/d to reduce risks of cancer. Deprivation of Se is associated with impairments in antioxidant protection, redox regulation and energy production as consequences of suboptimal expression of one or more of the Se-containing enzymes. These impairments may not cause deficiency signs in the classical sense, but instead contribute to health problems caused by physiological and environmental oxidative stresses and infections. At the same time, supranutritional intakes of Se, i.e. intakes greater than those required for selenocysteine enzyme expression, appear to reduce cancer risk. The lower, nutritional, level is greater than the typical intakes of many people in several parts of the world, and few populations have intakes approaching the latter, supranutritional, level. Accordingly, low Se status is likely to contribute to morbidity and mortality due to infectious as well as chronic diseases, and increasing Se intakes in all parts of the world can be expected to reduce cancer rates.

Alcohol and oxidative liver injury

Acute and chronic ethanol treatment has been shown to increase the production of reactive oxygen species, lower cellular antioxidant levels, and enhance oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury. Many of the seminal reports in this topic have been published in Hepatology , and it is fitting to review this research area for the 25th Anniversary Issue of the Journal.

Oxidative status in patients with alcohol dependence: a clinical study in Taiwan

The aim of this study is to examine the relationship between alcohol dependence and oxidative status. The biochemical parameters and antioxidants status were measured among 28 patients with alcohol dependence. Nineteen healthy persons without drinking problem were recruited as the control subjects. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (gamma-GT), and levels of cholesterol, triglyceride (TG), and uric acid were significantly increased in the specimen of patients compared with control. Serum malondialdehyde (MDA) levels of the patients were found to be significantly increased compared with controls and decreased after abstinence. Superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities were, respectively, 86% and 37% lower in alcoholic patients. After 14 d of abstinence, SOD activity was significantly reduced by 85%, CAT by 52%, and GPX by 54%, whereas no change was found in activity of glutathione reductase (GR). The duration of alcohol dependence is significantly correlated with the levels of MDA. In addition, the activity of CAT was significantly correlated with MDA levels. The results of this study suggest that oxidative stress occurred during alcohol dependence and subsequently affected the antioxidants mechanisms.

N-acetylcysteine attenuates alcohol-induced oxidative stress in he rat

AIM: There is increasing evidence that alcohol-induced liver damage may be associated with increased oxidative stress. We aimed to investigate free-radical scavenger effect of n-acetylcysteine in rats intragastrically fed with ethanol.

METHODS: Twenty-four rats divided into three groups were fed with ethanol (6 g/kg/d, Group 1), ethanol and n-acetylcysteine (1 g/kg, Group 2), or isocaloric dextrose (control group, Group 3) for 4 wk. Then animals were sacrificed under ether anesthesia, intracardiac blood and liver tissues were obtained. Measurements were performed both in serum and in homogenized liver tissues. Malondialdehyde (MDA) level was measured by TBARS method. Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels were studied by commercial kits. Kruskal-Wallis test was used for statistical analysis.

RESULTS: ALT and AST in Group 1 (154 U/L and 302 U/L, respectively) were higher than those in Group 2 (94 U/L and 155 U/L) and Group 3 (99 U/L and 168 U/L) (P = 0.001 for both). Serum and tissue levels of MDA in Group 1 (1.84 nmol/mL and 96 nmol/100 mg-protein) were higher than Group 2 (0.91 nmol/mL and 64 nmol/100 mg-protein) and Group 3 (0.94 nmol/mL and 49 nmol/100 mg-protein) (P < 0.001 for both). On the other hand, serum GSH-Px level in Group 1 (8.21 U/g-Hb) was lower than Group 2 (16 U/g-Hb) and Group 3 (16 U/g-Hb) (P < 0.001). Serum and liver tissue levels of SOD in Group 1 (11 U/mL and 26 U/100 mg-protein) were lower than Group 2 (18 U/mL and 60 U/100 mg-protein) and Group 3 (20 U/mL and 60 U/100 mg-protein) (P < 0.001 for both).

CONCLUSION: This study demonstrated that ethanol-induced liver damage is associated with oxidative stress, and co-administration of n-acetylcysteine attenuates this damage effectively in rat model.

Nutritional intake of hazardous drinkers and dependent alcoholics in the UK

There are no recent assessments of nutritional intake in alcohol misusers in the United Kingdom. The purpose of this study was to measure nutritional intake in alcoholics attending an Alcohol Misuse outpatient clinic in an inner city general hospital in the United Kingdom and relating this to various measures of alcohol dependence. All patients (n = 30; 27 male, 3 female) consumed at least 100 g ethanol per day (mean 162 g/day) for at least 5 years and completed questionnaires on socio-demographics, alcohol dependency and psychosocial problems and had assays of biochemical and haematological indices. The data were analysed first with respect to the entire patient population and then according to the degree of alcohol dependency (mild, moderate or severe). The results showed that with respect to the entire patient group, one-third were below normal body weights, but one-quarter was overweight. The total energy intake (kJ/day) including alcohol was apparently adequate with respect to recommended levels in most patients. On average, approx. 60% of energy intake came from alcohol. The whole patient population had a low intake of one or more macro- and micro-nutrient compared to the dietary reference requirements. All patients had intakes of vitamin E and folate below UK recommended standards, while 85 - 95% of patients had low intakes of selenium and Vitamin D. Between 50 and 85% of all patents had intakes below UK recommended standards in calcium and zinc and Vitamins A, B(1), B(2), B(6) and C. There were significant correlations between calorie intake (when alcohol was excluded) and vitamins B(1), B(2), B(6) and C, and Ca, Mg, Fe and Zn intake. There were no correlations between alcohol intake with any of the nutritional and anthropometric variables or between the three subgroups with respect to daily energy, micro- and macro-nutrient intakes. In conclusion, malnutrition was common in this patient group: all subjects had intakes below UK recommended standards in one or more micro- or macro-nutrient. However, there was no difference in the degree of malnutrition between the harmful drinkers (mild dependency) and heavily dependent subgroups.

Nutritional deficiencies in German middle-class male alcohol consumers: relation to dietary intake and severity of liver disease

OBJECTIVE

The purpose of the present study was to compare the nutrient intake and the nutritional status between German middle-class alcohol consumers and non-drinkers.

DESIGN

Cross-sectional study using patients with different stages of alcoholic liver disease (ALD) and healthy volunteers.

SETTING

Southern Germany.

SUBJECTS

Seventy-six hospitalized German middle-class alcohol consumers with different stages of alcoholic liver disease (ALD) and 22 healthy control subjects.

METHODS

Subjects and controls were nutritionally assessed and mineral and vitamin content was measured in blood and urine.

RESULTS

When compared with controls, alcohol consumers had significantly higher intakes of total calories, but intake of non-alcoholic calories did not differ between groups (P<0.05). Among drinkers, there was a decrease in percentage of energy derived from protein and fat and a significant increase in carbohydrates (P<0.05). With the exception of vitamin E, micronutrient intake of alcoholics was equal to that of controls; however, blood vitamin (vitamin C, retinol, lycopene, alpha- and gamma-carotene) and trace element (selenium, zinc) concentrations of alcohol-drinking patients were lower than those of non-drinkers.

CONCLUSION

From the results of this study it is concluded that in German middle-class male alcohol consumers the status of several micronutrients is disturbed, although dietary intake hardly differs from that in non-alcoholic controls.

Role of selenium depletion in the etiopathogenesis of depression in patients with alcoholism [corrected]

Chronic heavy alcohol consumption adversely affects both macronutrients and micronutrients. Alcohol use affects selenium status. Considerable evidence suggests that selenium status may modify mental function. The author suggests that the effects of alcohol intake on mood, behavior, and cognition may be partly mediated by biological changes related to selenium deficiency. It has been observed that there is a trend towards the normalization of selenium levels in patients with alcoholism after a relatively short period of abstinence from alcohol. It has also been observed that when depression develops in persons with alcoholism, they are likely to improve fairly rapidly after a relatively short period of abstinence from alcohol without therapy aimed at the depressive symptoms. The author suggests that improvement in depressed patients after a period of abstinence from alcohol might be in part related to the normalization of selenium status. Treatment and prevention of comorbid alcoholism and mood disorders require more attention by research workers, practicing physicians, and the general public. Future studies of the etiology and pathogenesis of mood disorders in patients with alcoholism are merited.

The effects of acute melatonin and ethanol treatment on antioxidant enzyme activities in rat testes

The pineal hormone melatonin (N -acetyl, 5-methoxytryptamine) was recently accepted to act as an antioxidant under both in vivo and in vitro conditions. In this study, we examined the possible preventive effect of melatonin on ethanol-induced lipid peroxidation in rat testes. Thirty-seven male Wistar albino rats, 5.5--6 months old, were randomly divided into four groups (9--10 animals in each). The first group (control animals) received 4% ethanol at similar intervals to the experimental groups to equalize the stress effect. The second group received only melatonin i.p. 7 mg kg(-1)bw three times over 1.5 h intervals. The third group received only 30% alcohol 3 g kg(-1)bw twice daily. The fourth group were treated with melatonin and ethanol according to the above protocol, melatonin injections preceding ethanol treatments. The product of lipid peroxidation, malondialdehyde (MDA) and antioxidant enzymes, superoxide dismutase (Cu--Zn SOD), glutathione peroxidase (GPx) and catalase (CAT) were measured in the post-mitochondrial fraction of the testes. MDA levels were significantly increased due to acute ethanol intoxication. GPx activity was higher in the three experimental groups than the control levels. The activity of CAT was increased significantly in the melatonin plus ethanol-treated group but the other groups appeared not to be influenced by acute ethanol treatment. Cu--Zn SOD activity remained unaltered. These results suggest that antioxidants may be a protective agent for the testicular injury caused by ethanol consumption.

Serum selenium concentration in a representative sample of the Canarian population

The concentration of serum selenium in 395 individuals (187 males + 218 females) living in the Canary Islands, Spain was determined by hydride generation atomic absorption spectrometry. The mean selenium concentration was 74.7 +/- 25.2 microg/l ranging between 7.86 and 182.3 microg/l. Twenty-two adults (7.2% of the total) had serum selenium concentrations under 45 microg/l. It is widely accepted that below this selenium serum concentration (45 microg/l) there is an increased risk of cardiovascular disease and cancer. Our results fall within data recently published in other Spanish and European regions and are much lower than data observed in USA or seleniferous regions. The estimated Se intakes of our population were lower than the Recommended Dietary Allowances for American people. Individuals from Lanzarote had a mean Se concentration significantly higher than individuals from the other islands. This could be attributed to differences in Se content of soil and/or differences in dietary habits of the populations. Serum selenium concentration did not vary with the sex of the subjects. Individuals younger than 14 years old had a serum selenium concentration significantly lower than the rest of the individuals. No relationship with socio-economic status, educational level, smoking habits, physical exercise or beer consumption was found. However, individuals who consume wine more than three times a week showed higher selenium concentrations than individuals with lower consumption. Also, individuals with consumption above seven units of spirit drinks a week had the highest mean selenium concentration.

Content of liver and brain ubiquinol-9 and ubiquinol-10 after chronic ethanol intake in rats subjected to two levels of dietary alpha-tocopherol

To assess the effect of chronic ethanol ingestion in the content of the reduced forms of coenzymes Q9 (ubiquinol-9) and Q10 (ubiquinol-10) as a factor contributing to oxidative stress in liver and brain, male Wistar rats were fed ad libitum a basal diet containing either 10 or 2.5 mg alpha-tocopherol/100 g diet (controls), or the same basal diet plus a 32% ethanol-25% sucrose solution. After three months treatment, ethanol chronically-treated rats showed identical growth rates to the isocalorically pair-fed controls, irrespectively of alpha-tocopherol dietary level. Lowering dietary alpha-tocopherol led to a decreased content of this vitamin in the liver and brain of control rats, without changes in that of ubiquinol-9, and increased levels of hepatic ubiquinol-10 and total glutathione (tGSH), accompanied by a decrease in brain tGSH. At the two levels of dietary alpha-tocopherol, ethanol treatment significantly decreased the content of hepatic alpha-tocopherol and ubiquinols 9 and 10. This effect was significantly greater at 10 mg alpha-tocopherol/100 g diet than at 2.5, whereas those of tGSH were significantly elevated by 43% and 9%, respectively. Chronic ethanol intake did not alter the content of brain alpha-tocopherol and tGSH, whereas those of ubiquinol-9 were significantly lowered by 20% and 14% in rats subjected to 10 and 2.5 mg alpha-tocopherol/100 g diet, respectively. It is concluded that chronic ethanol intake at two levels of dietary alpha-tocopherol induces a depletion of hepatic alpha-tocopherol and ubiquinols 9 and 10, thus contributing to ethanol-induced oxidative stress in the liver tissue. This effect of ethanol is dependent upon the dietary level of alpha-tocopherol, involves a compensatory enhancement in hepatic tGSH availability, and is not observed in the brain tissue, probably due to its limited capacity for ethanol biotransformation and glutathione synthesis.

Selenium, zinc and copper plasma levels in intrahepatic cholestasis of pregnancy, in normal pregnancies and in healthy individuals, in Chile

BACKGROUND/AIMS

Low blood Se levels have been previously shown in normal pregnancies (third trimester) and significantly lower levels in patients with intrahepatic cholestasis of pregnancy (ICP), in Finland and in Chile, suggesting that a low or marginal dietary availability of Se may contribute to the pathogenesis of this disease. The aim of this study was to investigate whether a temporal change in plasma concentration of Se, and seasonal fluctuations in plasma concentrations of Se, Zn and Cu, could coincide with changes in the prevalence of ICP.

METHODS

A cross-sectional cohort study was done including 21 ICP patients, 98 women in the third trimester of a normal pregnancy, 29 non-pregnant women, and also 13 individuals (seven non-pregnant women and six men) who had been studied 9 years before. Plasma Se, Zn and Cu were measured by atomic spectroscopy. Plasma Se levels in the present study were compared to the results obtained 5 to 7 years before, employing identical methodology in similar population samples.

RESULTS

Plasma Se concentrations in non-pregnant women were higher than in the previous study: 1.43+/-0.34 micromol/l vs 0.85+/-0.13; p<0.001. In comparison to non-pregnant women, normal pregnancies near term had lower plasma levels of Se: 1.08+/-0.25 micromol/l; p<0.01, and Zn: 17.90+/-3.61 micromol/l vs 19.71+/-3.21; p<0.05, but higher plasma levels of Cu: 34.35+/-7.12 micromol/l vs 20.62+/-3.34; p<0.01. In normal pregnancies, plasma Se concentration was significantly higher in summer (1.34+/-0.19 micromol/l) than in the other seasons, while Zn and Cu diminished. Similar to previous studies, ICP patients had significantly lower Se plasma levels than normal pregnancies: 0.94+/-0.12 micromol/l, p<0.05, and Cu levels were significantly higher: 50.80+/-7.02 micromol/l, p<0.01. Cu plasma levels correlated with the biochemical severity of the disease. Zn did not change in ICP.

CONCLUSIONS

The present study shows that the decrease in the prevalence of ICP in Chile during the last decade coincides with an increase in plasma Se levels. Its lower incidence during summer coincides with a higher plasma Se concentration in summer than in other seasons, as observed in normal pregnancies.

[The impact of alcohol and chronic liver disease of micronutrients metabolism]

Liver disease, alcohol and malnutrition are combinations usually associated with micronutrient impairment. Chronic liver disease courses with lower storage and activation of vitamin-coenzymes related to their malabsorption. Alcohol worsens the picture by reducing food intake, increasing micronutrients utilization and decreasing their absorption secondary to either intestinal or pancreatic injuries. Other concurrent causes would be drug treatments, urinary losses, protein deficiency and oxidative stress. As consequences the clinical signs are anemia, liver steatosis, oxidative stress and immunosuppression.

HSP70 induction in the brain following ethanol administration in the rat: regulation by glutathione redox state

Changes in glutathione (GSH) and glutathione disulfide (GSSG) levels and/or redox status have been suggested to mediate the induction of heat shock proteins (HSPs) that follows exposure to oxidizing agents such as ethanol. Here we report the effects of ethanol administration to rats at intracellular levels of GSH, GSSG, HSP70, and protein carbonyls in brain and liver. Following 7 days of ethanol administration, there was a significant decrease in GSH, a significant induction of HSP70, and a significant increase in protein carbonyls in all brain regions studied and in liver. In cortex, striatum, and hippocampus there was a significant correlation between (a) the decrease in GSH, (b) the increase in GSSG, and (c) the decrease in GSH/GSSG ratio and HSP70 levels induced in response to ethanol. These data support the hypothesis that a redox mechanism may be involved in the heat-shock signal pathway responsible for HSP70 induction in the brain.

Interaction of 1-hydroxyethyl radical with antioxidant enzymes

There is considerable interest in the role of the 1-hydroxyethyl radical (HER) in the toxic effects of ethanol. The goal of this study was to evaluate the effects of HER on classical antioxidant enzymes. The interaction of acetaldehyde with hydroxylamine-o-sulfonic acid has been shown to produce 1, 1'-dihydroxyazoethane (DHAE); this compound appears to be highly unstable, and its decomposition leads to the generation of HER. Addition of DHAE into a solution of PBN led to the appearance of the typical EPR spectra of PBN/HER adduct. No PBN/HER spin adduct was detected when DHAE was incubated with 0.1 M PBN in the presence of GSH. In the absence of PBN, DHAE oxidized ascorbic acid to semidehydroascorbyl radical, presumably via an ascorbate-dependent one-electron reduction of HER back to ethanol. Catalase was progressively inactivated by exposure to DHAE-generated HER in a time and HER concentration-dependent manner. Ascorbic acid and PBN gave full protection to catalase against HER-dependent inactivation. The antioxidants 2-tert-butyl-4-methylphenol, propylgallate, and alpha-tocopherol-protected catalase against inactivation by 84, 88, and 39%, respectively. Other antioxidant enzymes were also sensitive to exposure to HER. Glutathione reductase, glutathione peroxidase, and superoxide dismutase were inactivated by 46, 36, and 39%, respectively, by HER. The results reported here plus previous results showing HER interacts with GSH, ascorbate, and alpha-tocopherol suggest that prolonged generation of HER in cells from animals chronically exposed to ethanol may lower the antioxidant defense status, thereby contributing to mechanisms by which ethanol produces a state of oxidative stress and produces toxicity.

ESR and HPLC-EC analysis of ethanol oxidation to 1-hydroxyethyl radical: rapid reduction and quantification of POBN and PBN nitroxides

Extensive ESR spin-trapping studies have shown that ethanol is oxidized to 1-hydroxyethyl radical (HER) by rat and deer mice liver microsomal systems. The ESR detection of POBN/HER nitroxide in bile, and formation of antibodies, which recognize HER adducts in alcoholics, suggest that HER is produced in vivo. In liver, where ethanol is primarily metabolized, only traces of PBN/HER nitroxide are documented. One limitation of the ESR spin-trapping technique, however, is that the nitroxides formed in the presence of cellular reductants can be metabolized to the corresponding ESR "silent" hydroxylamines. Ascorbate and NADPH plus liver microsomes were found to reduce rapidly both POBN/HER and PBN/HER nitroxides to their ESR "silent" hydroxylamine derivatives. An HPLC method with electrochemical detection was developed for the detection and quantification of both POBN/HER and PBN/HER nitroxides, as well as their hydroxylamines. Both the diastereomers of the POBN/HER nitroxide and hydroxylamine can be detected, as can both isomers of the PBN/HER nitroxide, and it is estimated that the sensitivity of the HPLC procedure is in the nM range when using EC detection. The hydroxylamines are stable in ethanol, while pH-dependent auto-oxidation occurs in aqueous buffers. Some of the characteristics associated with HER formation by microsomes as detected with ESR (e.g., sensitivity to SOD and catalase, increase after induction of CYP2E1) are reproduced with the HPLC method. By quantification of the POBN/HER hydroxylamine, the NADPH-dependent rates of HER formation by microsomes from pyrazole-treated rats are estimated to be about 1-1.5 nmol HER per min per mg microsomal protein. This rate is less, as compared to the two electron-dependent rate of acetaldehyde formation by these microsomes, about 10-15 nmol per min per mg protein. Thus, at first approximation, the one electron-dependent rate of ethanol oxidation is about 10% the two electron-dependent rate by isolated microsomes. The HPLC procedure can readily detect the POBN/HER and PBN/HER nitroxides and their hydroxylamine derivatives in the same sample and may be of value in detecting HER spin-trapped adducts under biological reducing conditions.

Interaction of 1-hydroxyethyl radical with glutathione, ascorbic acid and alpha-tocopherol

Ethanol has been shown to be oxidized to a free radical metabolite, the 1-hydroxyethyl radical (HER). Interaction of HER with cellular antioxidants may contribute to the known ability of ethanol administration to lower levels of GSH and alpha-tocopherol. Experiments were carried out to establish a model system for the generation of HER and to study its interaction with GSH, ascorbic acid and alpha-tocopherol. A standard reaction for formation of azo-compounds using acetaldehyde and hydroxylamine-O-sulfonic acid was applied for the synthesis of 1,1'-dihydroxyazoethane (CH3CH(OH)-N=N-CH(OH)CH3). Although stable at -70 degrees C, thermal decomposition of this compound at room temperature was shown to produce HER, detected by EPR spectrometry as the PBN/HER or DMPO/HER spin adducts, and validated by computer simulation. GSH, present at the beginning of the experiment, inhibited formation of the PBN/HER signal. However, GSH did not cause any decay of pre-formed PBN/HER spin adduct. GSH was consumed in the presence of the HER-generating system in a reaction largely reversed by addition of NADPH plus glutathione reductase. Ascorbate also inhibited formation of the PBN/HER spin adduct and rapidly reduced the pre-formed adduct. HER amplified the oxidation of ascorbate, which was associated with the formation of the semidehydroascorbyl radical. Alpha-tocopherol was also consumed in the presence of HER. Production of HER in intact HepG2 cells by the redox cycling of 2,3-dimethoxy-1,4-naphthoquinone was associated with consumption of GSH. These data demonstrate the use of a simple chemical system for the controlled, continuous formation of HER and indicate that cellular antioxidants such as GSH, ascorbate, and alpha-tocopherol, interact with HER. The ability of agents such as ascorbate to reduce the PBN/HER spin adduct to EPR-silent product(s) may mask the quantitative detection of HER in biological systems.

Pathogenesis of alcoholic liver disease with particular emphasis on oxidative stress

Oxidative stress is well recognized to be a key step in the pathogenesis of ethanol-associated liver injury. Ethanol administration induces an increase in lipid peroxidation either by enhancing the production of oxygen reactive species and/or by decreasing the level of endogenous antioxidants. Numerous experimental studies have emphasized the role of the ethanol-inducible cytochrome P450 in the microsomes and the molybdo-flavoenzyme xanthine oxidase in the cytosol. This review shows the putative role of ethanol-induced disturbances in iron metabolism in relation to iron as a pro-oxidant factor. Ethanol administration also affects the mitochondrial free radical generation. Many previous studies suggest a role for active oxygens in ethanol-induced mitochondrial dysfunction in hepatocytes. Recent studies in our laboratory in the Department of Internal Medicine, Keio University, using a confocal laser scanning microscopic system strongly suggest that active oxidants generated during ethanol metabolism produce mitochondrial membrane permeability transition in isolated and cultured hepatocytes. In addition, acetaldehyde, ethanol consumption-associated endotoxaemia and subsequent release of inflammatory mediators may cause hepatocyte injury via both oxyradical-dependent and -independent mechanisms. These cytotoxic processes may lead to lethal hepatocyte injury. Investigations further implicate the endogenous glutathione-glutathione peroxidase system and catalase as important antioxidants and cytoprotective machinery in the hepatocytes exposed to ethanol.

Deficiency in antioxidant factors in patients with alcohol-related chronic pancreatitis

Free radicals have been suspected to play a role in the pathogenicity of alcohol-related chronic pancreatitis. The aim of this study was to determine the status of several antioxidant parameters in these patients and examine the factors that are likely to influence them. Thirty-five subjects (23 males and 12 females, mean age 48 +/- 8 years) with disease proven by endoscopic pancreatography and 14 healthy controls (6 males and 8 females, mean age 44 +/- 7 years) were included in the study. Biochemical antioxidant parameters included: selenium, zinc, and copper levels in plasma; glutathione peroxidase in plasma and erythrocytes; plasma malondialdehyde concentrations assessed by thiobarbituric acid reactants; and serum vitamin E and A levels. Selenium and vitamin E oral intake was assessed by a five-day diet analysis. Hemoglobin (130 +/- 16 vs 143 +/- 15 g/liter), vitamin E (8 +/- 5 vs 16 +/- 9 mg/liter), vitamin A (30 +/- 11 vs 49 +/- 12 micrograms/dl), selenium (54 +/- 20 vs 87 +/- 11 micrograms/liter), and plasma glutathione peroxidase (903 +/- 313 vs 1326 +/- 168 units/liter) were significantly lower in patients than in controls (P < 0.05). In contrast, white blood cell count, C-reactive protein, and plasma copper levels were significantly higher in patients than in controls. Cholesterol, triglycerides, iron, ferritin, total proteins, zinc, and malondialdehyde were not different. Vitamin E was lower in patients with steatorrhea, while vitamin A was lower in patients with concomitant diabetes mellitus. Dietary intakes were not different between patients and controls. In conclusion, patients with alcohol-related chronic pancreatitis have low blood levels in many antioxidant factors. Dietary intakes of some of them (selenium and vitamin E) are adequate, however. Such deficiencies are secondary to pancreatic insufficiency and probably to increased requirements related to enhanced oxidative stress.

Urinary selenium in healthy and diabetic Saudi Arabians

We examined Se in urine of 170 Saudi Arabian diabetics (19 insulin-dependent [type 1] and 151 insulin-independent [type 2]) and in an equal number of control subjects of the same origin by measuring the ratio of the concentration of this metal (C(Se)) to that of creatinine in urine (C(creat)) for each subject. The mean (and SEM) of C(Se) /C(creat) for the control subjects was 56 (2.9) mu mol/mol creat, whereas, the value for the diabetics combined or separated into type 1 and type 2 was 56.7 (3.2), 51.5 (6.3), and 57.4 (3.5) mu mol/mol creat, respectively. With the exception of type 2 diabetics who were treated with insulin in addition to oral hypoglycemic and diet (35 patients) (mean [SEM] = 43 (4.3) mu mol/mol creat), there was no significant difference in C(Se)/C(creat) between the diabetics and control subjects. Also, there was no significant correlation between C(Se)/C(creat) and age, sex, or weight of diabetics, whereas, the correlation with the degree of diabetic control was significant (p < 0.0136). Of all diabetes-associated disorders (cardiovascular diseases, neuropathy, ophthalmologic diseases, infections, and hepatic disease), only ophthalmologic diseases appears to cause a significant (p < 0.05) reduction in C(Se)/C(creat), but only among type 2 diabetics. Inasmuch as Se status is reflected by urinary Se, healthy Saudi Arabians appear to have Se status that is comparable or higher than those reported for other populations.

Acute and chronic hepatic steatosis lead to in vivo lipid peroxidation in mice

BACKGROUND/AIMS

Several liver diseases that are characterized by chronic steatosis lead to steatohepatitis lesions in some susceptible subjects. We tested the hypothesis that acute or chronic steatosis may lead to lipid peroxidation.

METHODS

Diverse steatogenic treatments were administered to mice, and lipid peroxidation was assessed by measuring thiobarbituric acid reactants in the liver and the exhalation of ethane in breath.

RESULTS

Administration of ethanol (5 g/kg), tetracycline, chlortetracycline, demeclocycline (0.25 mmol/kg each), amineptine (1 mmol/kg), amiodarone (1 mmol/kg), pirprofen (2 mmol/kg), or valproate (2 mmol/kg) led to microvesicular steatosis of the liver and lipid peroxidation. After tetracycline administration, hepatic triglycerides reached a maximum at 24 h and then declined; ethane exhalation followed a similar time course. Microvesicular steatosis and lipid peroxidation were also observed after 4 days of treatment with either ethionine (0.02 mmol/kg daily) or dexamethasone (0.25 mmol/kg daily) or after 7 days of tetracycline (0.25 mmol/kg daily) administration. Administration of ethanol in the drinking water for 5.5 months led to macrovacuolar and microvesicular steatosis, lipid peroxidation, and a few necrotic hepatocytes.

CONCLUSIONS

We conclude that acute or chronic fat deposition due to a variety of compounds was associated with lipid peroxidation in mice. We suggest that the presence of oxidizable fat in the liver leads to peroxidation, and that chronic lipid peroxidation might represent the common (but not exclusive) mechanism for the possible development of steatohepatitis lesions in conditions characterized by chronic steatosis.

Effects of long-term vitamin E supplementation in alcoholic cirrhotics

OBJECTIVE

Alcohol ingestion promotes lipoperoxidation and alters cellular antioxidant mechanisms. Alpha-tocopherol levels decrease in alcoholics as severity of liver damage increases. The aim of this protocol was to study the effects of a long-term oral 500 mg vitamin E daily supplementation in decompensated ambulatory alcoholic cirrhotics.

PATIENTS AND METHODS

67 subjects were included in this double blind trial; 33 patients received vitamin E and 34 patients received placebo tablets of identical appearance during 1 year. Each month, the patients were seen by a nurse practitioner who was in charge of detecting alcohol ingestion and checking adherence to treatment. Every 3 months, the patients underwent a medical examination, and blood samples were taken for clinical laboratory analysis and serum vitamin E measurement.

RESULTS

Alpha-tocopherol levels were significantly lower in patients with more severe liver disease. This difference was not significant when vitamin E levels were corrected by cholesterol. Oral supplementation significantly increased serum vitamin E levels in the experimental group. Alcohol ingestion and hospitalization rates were similar in both groups. Life table analysis did not show significant differences in mortality between the two groups.

DISCUSSION

Vitamin E supplementation with adequate doses of an alpha-tocopheryl acetate formulation during 1 year did not influence hepatic laboratory parameters, mortality or hospitalization rates of decompensated alcoholic cirrhotics, although serum levels of the vitamin significantly increased.

Urinary selenium status of healthy people

Urinary selenium (Se) concentrations (microgram/l of urine and microgram/g of creatinine) and urinary Se excretions (microgram/d and microgram/d.kg of body weight) have been determined in healthy Canarian people. Urinary Se status was relatively low and similar to those data published from European regions. Females excreted daily significantly (P = 0.005) higher amounts of Se per kg of body weight in urine than males. An increase of daily urinary Se excretion was observed up to 30 years of age. Children (< 10 years old) had daily urinary Se excretion per kg of body weight higher than persons with age > 10 years old. Both units of Se excretion, microgram/d and microgram/d.kg, increased or decreased respectively with weight and height of the individuals. Food habits such as consumption of rich protein or rich fibre food, and drinking alcohol or coffee as well as smoking do not seem to influence the urinary Se status. Depletion of daily urinary Se excretion was observed with the increase of physical exercise. Unit of concentration (microgram/g of creatinine) is a more adequate indicator of the urinary Se excretion than the unit microgram/l.

Low selenium status in alcoholic cirrhosis is correlated with aminopyrine breath test. Preliminary effects of selenium supplementation

The relationship among impaired selenium status, lipid peroxidation, and liver function was examined in 19 hospitalized patients with severe alcoholic cirrhosis. Plasma selenium was found to be significantly lower (mean +/- SD: 54 +/- 13 micrograms/L) than in healthy controls (83 +/- 11 micrograms/L) and plasma malondialdehyde, assessed as thiobarbituric acid reactants, which reflects lipid peroxidation, was increased (2.0 +/- 1.2 mumol/L vs < 1.2 mumol/L in controls). The mean 14C aminopyrine breath test, an indicator of liver function, was lower than normal (2.7 +/- 1.9 vs 6.3 +/- 0.9% in controls) and found to be significantly correlated with plasma selenium (r = 0.59, p < 0.05). A prospective, randomized selenium supplementation trial was conducted in a group of 16 patients who received either daily 100 micrograms selenium as enriched yeast during 4 mo or a placebo. Among the 10 patients who completed the study, plasma selenium significantly increased in the supplemented group (n = 4; before: 58 +/- 10 micrograms/L, and after 101 +/- 12 micrograms/L, p < 0.01) contrary to the placebo group (n = 6, before: 47 +/- 10 micrograms/L, after: 57 +/- 9 micrograms/L, n.s.). 14C aminopyrine breath test improved in three out of four selenium-supplemented patients and in three out of six placebo patients, but the small number of patients did not allow statistical evaluation. These results demonstrate that low selenium status in alcoholic cirrhosis is correlated to liver function and could be improved by supplementation.

Monitoring oxidative damage in patients with liver cirrhosis and different daily alcohol intake

This study looked at the possible association between alcohol abuse and free radical mediated oxidative injury by examining the presence of oxidative damage, as monitored by erythrocyte malonildialdehyde and plasma lipid hydroperoxides, in patients with liver cirrhosis and different lifetime daily alcohol intake. All patients with an alcohol intake above 100 g/day (ALC) showed concentrations of malonildialdehyde and lipid hydroperoxide on average four to fivefold higher than cirrhotic patients with alcohol intake below 100 g/day (NAC) or healthy controls. Further subgrouping of ALC patients showed that those with alcohol intake ranging between 100 and 200 g/day (ALC1) had malonildialdehyde and lipid hydroperoxide concentrations significantly lower than those with an intake higher than 200 g/day (ALC2). These differences were not related to the extent of liver injury or to the liver derangement as assessed by Child's classification. The increase in lipid peroxidation markers in ALC cirrhotic patients was associated with a decrease in, respectively, plasma alpha-tocopherol and erythrocyte glutathione concentrations. Significant differences were also seen between ALC1 and ALC2 groups in plasma alpha-tocopherol, but not in erythrocyte glutathione concentrations. The concentrations of alpha-tocopherol and glutathione in the blood of NAC patients were in contrast not substantially different from those of healthy controls. The close association between oxidative damage and alcohol abuse suggested that free radical intermediates produced during ethanol metabolism might be responsible for causing oxidative damage.

Hypothalamic-pituitary-thyroid axis in chronic alcoholism. II. Deiodinase activities and thyroid hormone concentrations in brain and peripheral tissues of rats chronically exposed to ethanol

Thyroxine (T4), triiodothyronine (T3) concentrations, and the activities of the three deiodinase isoenzymes were measured in different brain regions and peripheral tissues of rats. According to an animal model of alcohol addiction, "behaviorally" dependent rats having lost control over their intake of ethanol were compared with alcohol-naive controls and ethanol-experienced, but "controlled" consumers. The two kinds of alcohol-experienced rats were investigated either 24 hr or 3 months after ethanol withdrawal. The results of these four groups were compared with those of an ethanol-naive control group. During withdrawal, the activities of type II 5'-deiodinase (which catalyzes deiodination of T4 and T3 in the CNS) in both the "behaviorally dependent" rats and the "controlled drinkers" were significantly lower than in the alcohol-naive controls in the frontal cortex, parieto-occipital cortex, hippocampus, and striatum, but not in the cerebellum or pituitary. Probably as a result, the tissue concentrations of T4 were higher in areas of the CNS in the groups exposed to alcohol. However, the T3 concentrations were normal. No relevant differences were seen between the activities of type III 5-deiodinase (which catalyzes the further deiodination of T3) observed in these groups. After 3 months of abstinence, the type II 5'-deiodinase activities had almost returned to normal in both "controlled drinkers" and "behaviorally dependent" animals, whereas type III 5-deiodinase activity was inhibited, possibly to maintain physiological concentrations of T3 during abstinence. Indeed, the tissue levels of T3 were normal in the areas of the CNS, and the T4 levels were still elevated. However, the liver concentrations of T3 and T4 were significantly lower in the "behaviourally dependent" animals than in the "controlled" drinkers after 3 months of abstinence, whereas no differences were found between the T4 and T3 concentrations in the areas of the CNS investigated in the two groups exposed to ethanol. These results suggest that chronic administration of ethanol affects intracellular thyroid hormone metabolism in both rat CNS and liver in the highly complex manner. No direct evidence of ethanol-induced enhancement of tissue uptake or concentrations was obtained. However, taking into account the numerous similarities between the clinical picture of hyperthyroidism and the symptomatology of alcoholism, it may be hypothesized that ethanol may directly influence any step in the as yet unknown biochemical cascade of thyroid hormone function.

Alcohol and the liver: 1994 update

This article reviews current concepts on the pathogenesis and treatment of alcoholic liver disease. It has been known that the hepatotoxicity of ethanol results from alcohol dehydrogenase-mediated excessive generation of hepatic nicotinamide adenine dinucleotide, reduced form, and acetaldehyde. It is now recognized that acetaldehyde is also produced by an accessory (but inducible) microsomal pathway that additionally generates oxygen radicals and activates many xenobiotics to toxic metabolites, thereby explaining the increased vulnerability of heavy drinkers to industrial solvents, anesthetics, commonly used drugs, over-the-counter medications, and carcinogens. The contribution of gastric alcohol dehydrogenase to the first-pass metabolism of ethanol and alcohol-drug interactions is discussed. Roles for hepatitis C, cytokines, sex, genetics, and age are now emerging. Alcohol also alters the degradation of key nutrients, thereby promoting deficiencies as well as toxic interactions with vitamin A and beta carotene. Conversely, nutritional deficits may affect the toxicity of ethanol and acetaldehyde, as illustrated by the depletion in glutathione, ameliorated by S-adenosyl-L-methionine. Other "supernutrients" include polyunsaturated lecithin, shown to correct the alcohol-induced hepatic phosphatidylcholine depletion and to prevent alcoholic cirrhosis in nonhuman primates. Thus, a better understanding of the pathology induced by ethanol is now generating improved prospects for therapy.

Mechanisms of ethanol-drug-nutrition interactions

Mechanisms of the toxicologic manifestations of ethanol abuse are reviewed. Hepatotoxicity of ethanol results from alcohol dehydrogenase-mediated excessive hepatic generation of nicotinamide adenine dinucleotide and acetaldehyde. It is now recognized that acetaldehyde is also produced by an accessory (but inducible) pathway, the microsomal ethanol-oxidizing system, which involves a specific cytochrome P450. It generates oxygen radicals and activates many xenobiotics to toxic metabolites, thereby explaining the increased vulnerability of heavy drinkers to industrial solvents, anesthetics, commonly used drugs, over-the-counter medications and carcinogens. The contribution of gastric alcohol dehydrogenase to the first pass metabolism of ethanol and alcohol-drug interactions is now recognized. Alcohol also alters the degradation of key nutrients, thereby promoting deficiencies as well as toxic interactions with vitamin A and beta-carotene. Conversely, nutritional deficits may affect the toxicity of ethanol and acetaldehyde, as illustrated by the depletion in glutathione, ameliorated by S-adenosyl-L-methionine. Other supernutrients include polyenylphosphatidylcholine, shown to correct the alcohol-induced hepatic phosphatidylcholine depletion and to prevent alcoholic cirrhosis in non-human primates. Thus, a better understanding of the pathology induced by ethanol has now generated improved prospects for therapy.

Effects of chronic alcohol feeding and murine AIDS virus infection on liver antioxidant defense systems in mice

Whether ethanol (ETOH) abuse could contribute to the development of acquired immunodeficiency syndrome (AIDS) among human immunodeficiency virus (HIV)-positive drug abusers is a critical question for which little experimental information is available. This study was designed to determine if chronic ETOH feeding and murine AIDS virus infection cooperatively affected liver antioxidant defense systems in C57B1/6 female mice. Mice were divided into two groups and fed the Lieber-DeCarli liquid ETOH diet containing ETOH at a concentration to provide 31% of total caloric intake or an isocaloric liquid control (control) diet in which dextrin-maltose replaced ETOH. One week after the initiation of ETOH feeding, half of the mice in each diet group (8 mice) were injected intraperitoneally with murine retrovirus (MAIDS) stock. After 3 and 5 weeks of ETOH feeding, half of the mice in each of the four treatment groups (4 mice) were killed, and livers were excised for biochemical analysis. Liver reduced glutathione (GSH) levels and activities of glutathione peroxidase (GP), glutathione reductase (GR), glutathione transferase (GT), catalase and superoxide dismutase (SOD), and serum ETOH concentrations were determined. The results demonstrated that serum ETOH concentrations were significantly elevated in ETOH-MAIDS group when compared with the ETOH group. Moreover, chronic ETOH feeding and MAIDS infection independently depressed liver antioxidant defense capability, and together led to an additive inhibition of GSH and SOD activities. In addition, MAIDS infection inhibited an ETOH-induced increase in catalase and GT activities. These results suggest that alcohol abuse could contribute to the development of AIDS by inhibiting the protective capability of an infected individual against oxidative stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Aetiology and pathogenesis of alcoholic liver disease

Until the 1960s, liver disease of the alcoholic patient was attributed exclusively to dietary deficiencies. Since then, however, our understanding of the impact of alcoholism on nutritional status has undergone a progressive evolution. Alcohol, because of its high energy content, was at first perceived to act exclusively as 'empty calories' displacing other nutrients in the diet, and causing primary malnutrition through decreased intake of essential nutrients. With improvement in the overall nutrition of the population, the role of primary malnutrition waned and secondary malnutrition was emphasized as a result of a better understanding of maldigestion and malabsorption caused by chronic alcohol consumption and various diseases associated with chronic alcoholism. At the same time, the concept of the direct toxicity of alcohol came to the forefront as an explanation for the widespread cellular injury. Some of the hepatotoxicity was found to result from the metabolic disturbances associated with the oxidation of ethanol via the liver alcohol dehydrogenase (ADH) pathway and the redox changes produced by the generated NADH, which in turn affects the metabolism of lipids, carbohydrates, proteins and purines. Exaggeration of the redox change by the relative hypoxia which prevails physiologically in the perivenular zone contributes to the exacerbation of the ethanol-induced lesions in zone 3. In addition to ADH, ethanol can be oxidized by liver microsomes: studies over the last twenty years have culminated in the molecular elucidation of the ethanol-inducible cytochrome P450IIE1 (CYP2E1) which contributes not only to ethanol metabolism and tolerance, but also to the selective hepatic perivenular toxicity of various xenobiotics. Their activation by CYP2E1 now provides an understanding for the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, 'over the counter' analgesics, chemical carcinogens and even nutritional factors such as vitamin A. Ethanol causes not only vitamin A depletion but it also enhances its hepatotoxicity. Furthermore, induction of the microsomal pathway contributes to increased acetaldehyde generation, with formation of protein adducts, resulting in antibody production, enzyme inactivation and decreased DNA repair; it is also associated with a striking impairment of the capacity of the liver to utilize oxygen. Moreover, acetaldehyde promotes glutathione depletion, free-radical mediated toxicity and lipid peroxidation. In addition, acetaldehyde affects hepatic collagen synthesis: both in vivo and in vitro (in cultured myofibroblasts and lipocytes), ethanol and its metabolite acetaldehyde were found to increase collagen accumulation and mRNA levels for collagen. This new understanding of the pathogenesis of alcoholic liver disease may eventually improve therapy with drugs and nutrients.

Increased ethane exhalation, an in vivo index of lipid peroxidation, in alcohol-abusers

Ethane exhalation was measured in 42 control subjects, 52 patients with various non-alcoholic liver diseases, and 89 alcohol abusers who had been admitted to hospital for alcohol withdrawal and assessment of liver disease (six with normal liver tests, 10 with steatosis with or without fibrosis, six with alcoholic hepatitis, 29 with cirrhosis, 34 with both cirrhosis and alcoholic hepatitis, and four with both cirrhosis and a hepatocellular carcinoma). Ethane exhalation was similar in control subjects and in patients with non-alcoholic liver diseases, but was five times higher in alcohol abusers. Ethane exhalation in alcohol abusers was significantly, but very weakly, correlated with the daily ethanol intake before hospital admission, and the histological score for steatosis, but not with the inflammation or alcoholic hepatitis scores. Ethane exhalation was inversely correlated with the duration of abstinence before the test. In nine alcoholic patients, the exhalation of ethane was measured repeatedly, and showed slow improvement during abstinence. Ethane exhalation was significantly but weakly correlated with the Pugh's score in patients with alcoholic cirrhosis. It is concluded that the mean ethane exhalation is increased in alcohol abusers. One of the possible mechanisms may be the presence of oxidizable fat in the liver. The weak correlation with the Pugh's score is consistent with the contribution of many other factors in the progression to severe liver disease.