Effect of moderate alcohol intake on lipid peroxidation in plasma, erythrocyte and leukocyte and on some antioxidant enzymes

Effect of Moderate Beer Intake on the Lipid Composition of Human Red Blood Cell Membranes

Background/Objectives: Growing evidence suggests that erythrocyte membrane lipids are subject to changes during their lifespan. Factors such as the type of dietary intake and its composition contribute to the changes in red blood cell (RBC) membranes. Due to the high antioxidant content of beer, we aimed to investigate the effect of moderate beer consumption on the lipid composition of RBCs membranes from healthy overweight individuals. Methods: We conducted a four-weeks, prospective two-arm longitudinal crossed-over study, where participants (n = 36) were randomly assigned to alcohol-free beer group or traditional beer group. The lipids of RBCs membranes were assessed at the beginning and the end of the intervention by thin-layer chromatography. Results: Four-weeks of alcohol-free beer promoted changes in fatty acids (FA), free cholesterol (FC), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) (p < 0.05). Meanwhile, traditional beer intake led to changes in FA, FC, phospholipids (PL), PE and PC (p < 0.05). The observed alterations in membrane lipids were found to be independent of sex and BMI as influencing factors. Conclusions: The lipid composition of erythrocyte membranes is distinctly but mildly influenced by the consumption of both non-alcoholic and conventional beer, with no effects on RBC membrane fluidity.

Oxidative Effects in Early Stages of Embryo Development Due to Alcohol Consumption

Alcohol, a widely consumed drug, exerts significant toxic effects on the human organism. This review focuses on its impact during fetal development, when it leads to a spectrum of disorders collectively termed Fetal Alcohol Spectrum Disorders (FASD). Children afflicted by FASD exhibit distinct clinical manifestations, including facial dysmorphism, delayed growth, and neurological and behavioral disorders. These behavioral issues encompass diminished intellectual capacity, memory impairment, and heightened impulsiveness. While the precise mechanisms underlying alcohol-induced fetal damage remain incompletely understood, research indicates a pivotal role for reactive oxygen species (ROS) that are released during alcohol metabolism, inciting inflammation at the cerebral level. Ethanol metabolism amplifies the generation of oxidant molecules, inducing through alterations in enzymatic and non-enzymatic systems responsible for cellular homeostasis. Alcohol consumption disrupts endogenous enzyme activity and fosters lipid peroxidation in consumers, potentially affecting the developing fetus. Addressing this concern, administration of metformin during the prenatal period, corresponding to the third trimester of human pregnancy, emerges as a potential therapeutic intervention for mitigating FASD. This proposed approach holds promise for ameliorating the adverse effects of alcohol exposure on fetal development and warrants further investigation.

Features of oxidative stress in alcoholism

The review considers molecular mechanisms underlying formation and development of oxidative stress (OS) in patients with alcohol dependence. The major attention is paid to the effects of ethanol and its metabolite acetaldehyde associated with additional sources of generation of reactive oxygen species (ROS) in response to exogenous ethanol. The own results of studies of the in vitro effect of ethanol and acetaldehyde on the concentration of peripheral OS markers - products of oxidative modification of proteins (protein carbonyls), lipids (lipid peroxidation products), DNA (8-hydroxy-2-deoxyguanosine, 8-OHdG) in blood plasma are presented. The changes in these parameters and the activity of antioxidant enzymes (SOD, catalase) in patients with alcohol dependence were analyzed. Own and literature data indicate that at a certain stage of the disease OS can play a protective rather than pathogenic role in the body.

Evaluation of oxidative stress markers in ethanol users

Ethanol is a central nervous system depressant that is widely consumed worldwide. When consumed chronically, it may have several consequences to the organism, such as oxidative stress. Ethanol metabolism increases the production of oxidant molecules and its consumption may cause changes in enzymatic and non-enzymatic systems that maintain cellular homeostasis. The activity of endogenous enzymes and lipid peroxidation are altered in alcohol consumers. Therefore, this study aimed to evaluate oxidative stress parameters in ethanol users compared to a control group. For that, the activity of the enzymes superoxide dismutase, catalase, and glutathione peroxidase, the ferric reducing/antioxidant power (FRAP), and malondialdehyde were evaluated. The influence of the amount of ethanol consumed on the analyzed parameters was also verified. The group of alcohol users consisted of 52 volunteers, 85% male and 15% female, with a mean age of 41±13 years. The control group consisted of 50 non-drinkers, 40% male and 60% female, with a mean age of 50±10 years. There was a significant difference in superoxide dismutase (P<0.001) and malondialdehyde (P=0.007) measurements between groups, as both parameters were increased in the group of ethanol users. Because of the higher amount of ethanol consumed, there was an increase of the catalase activity parameters and gradual reduction of FRAP. Thus, the ethanol-consuming participants were most likely under oxidative stress.

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.

Effects of trichlorfon on malondialdehyde and antioxidant system in human erythrocytes

Organophosphorus insecticides may induce oxidative stress leading to generation of free radicals and alteration in antioxidant system. The aim of this study was to examine the potency of trichlorfon, an organophosphate insecticide, to induce oxidative stress response in human erythrocytes in vitro. For this purpose trichlorfon solutions in different concentrations and erythrocyte solutions were incubated at 37 degrees C for 60 min. At the end of the incubation time, malondialdehyde (MDA), an end product of lipid peroxidation, total glutathione, reduced glutathione (GSH) levels, activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) enzymes were determined by spectrophotometric methods. Trichlorfon increased MDA formation depended on the concentration. On the other hand, decreases in the GSH-Px activity, GSH levels and increases in the total glutathione levels, SOD and CAT activities were seen in the studied concentrations. The present findings indicate that the in vitro toxicity of trichlorfon may be associated with oxidative stress.

Effect of hyperleptinaemia on chronic ethanol-induced hepatotoxicity in mice

Ethanol metabolism is accompanied by generation of free radicals, which stimulate lipid peroxidation. Previous studies have proposed a possible link between leptin and non-alcoholic fatty liver disease; however, the effect of leptin on ethanol-induced liver diseases remains unclear. The aim of the present study was to explore the effect of leptin on ethanol-induced liver injury in mice. Administering ethanol (6.32 g/kg body weight p.o.) to 4-week-old healthy mice for 45 days resulted in significantly elevated levels of plasma leptin, total bilirubin, gamma-glutamyl transpeptidase (GGT), tissue lipid hydroperoxides (LOOH), and lowered levels of tissue vitamins C and E when compared with those of the control mice. Subsequent to the experimental induction of hepatotoxicity (i.e. after the initial period of 30 days) exogenous leptin was administered (230 microg/kg body weight i.p.) every alternate day for 15 days along with the daily dose of ethanol. Leptin administration to control and ethanol-treated mice significantly reduced the weight gain, elevated the plasma levels of leptin, bilirubin, GGT and tissue LOOH, and significantly lowered the levels of tissue vitamins C and E when compared with the untreated control and ethanol-supplemented mice. It is postulated that the increase in systemic leptin levels enhances oxidative stress, and lowers antioxidant defence, leading to the augmented hepatic inflammation observed in alcoholic liver disease.

GPX1 Pro198Leu polymorphism, interactions with smoking and alcohol consumption, and risk for lung cancer

We genotyped blood samples from 432 lung cancer cases and 798 persons in a comparison group and examined the role of the GPX1 (Pro198Leu, rs1050450) polymorphism and interactions with external exposures in the development of lung cancer. The incidence rate ratio for lung cancer was 0.60 (95% confidence interval: 0.35-1.05) when homozygous carriers of the variant allele were compared with the homozygous carriers of the wild type, and the risk for lung cancer was significantly lower among participants carrying more variant alleles (p-trend=0.03). We found stronger associations between several smoking variables and alcohol intake and lung cancer risk among GPX1(TT) carriers than among GPX1(CC) and GPX1(CT) carriers.

Lipid hydroperoxide induced oxidative stress damage and antioxidant enzyme response in Caco-2 human colon cells

It has been demonstrated that reactive oxygen species, free radicals, and oxidative products, such as lipid hydroperoxides, participate in tissue injuries and in the onset and progression of degenerative diseases in humans. Studies were conducted using Caco-2 colon carcinoma cells to evaluate cellular damage caused by exposing cells for 30 min to oleic acid hydroperoxides (OAHPx) at concentrations varying from 0 to 25 microM. Cell membrane damage and DNA damage were significantly high even at the lowest concentration of 2.5 microM OAHPx compared to the control. Cell lipid peroxidation, indicated by conjugated diene concentration, increased exponentially with increasing OAHPx concentration. Antioxidant mechanisms in Caco-2 cells were evaluated by measuring catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities. Cellular catalase and GPx activities were not significantly different from each other at 0 to 25 microM OAHPx concentrations. SOD activity decreased with increasing OAHPx concentration. These results show that existing enzymatic antioxidant mechanisms are not sufficient for complete detoxification of 5-25 microM lipid hydroperoxides.

Associations between GPX1 Pro198Leu polymorphism, erythrocyte GPX activity, alcohol consumption and breast cancer risk in a prospective cohort study

Breast cancer may be related to oxidative stress. Breast cancer patients have been reported to have lower antioxidant enzyme activity than healthy controls and the polymorphism GPX1 Pro198Leu has been associated with risk of lung and breast cancer. The purpose of the present nested case-control study was to determine whether GPX1 Pro198Leu and glutathione peroxidase (GPX) activity in prospectively collected blood samples are associated with breast cancer risk among postmenopausal women and whether GPX activity levels are associated with other known breast cancer risk factors. We matched 377 female breast cancer cases with 377 controls all nested within the prospective 'Diet, Cancer and Health' study of 57 000 Danes. Carriers of the variant T-allele of GPX1 Pro198Leu were at 1.43-fold higher risk of breast cancer compared with non-carriers (95% CI=1.07-1.92). Pre-diagnostic GPX activity tended to be lower in cases compared with controls. GPX activity was positively correlated with intake of alcohol (P<0.0001) and the catalytic activity was lowered 5% for each additional copy of the variant T-allele (P=0.0003). Alcohol intake was correlated with increased GPX activity for the C-allele but not for the T-allele. Results from this prospective study suggest that the GPX1 Pro198Leu-associated lowered GPX activity is associated with higher breast cancer risk among Danish women.

Oxidative stress and antioxidant status in patients with alcoholic liver disease

BACKGROUND

[corrected] Alcoholic liver diseases (ALD) are very common in lower socio-economical strata due to heavy drinking habits and multiple nutritional deficiencies. Ethanol causes liver damage by many mechanisms. The generation of lipid peroxidation by free radicals has been proposed as a mechanism for ethanol induced hepatotoxicity. These free radicals are destroyed by anti-oxidants. Many anti-oxidants are present in the diet, e.g., vitamin E, vitamin C etc. However, poor nutrition or malabsorption leads to deficiency of these vitamins. This may impair the anti-oxidative defense leading to ethanol induced oxidative stress and then to liver damage.

METHODS

Oxidative stress and antioxidant defense were assessed in patients with alcoholic liver disease. Serum malondialdehyde (MDA) concentrations were measured as an index of lipid peroxidation, i.e., oxidative stress; and serum vitamins E and C concentrations were measured as an index of antioxidant status.

RESULTS

Serum MDA concentrations were increased with the increase in severity of the disease. Concentrations of serum vitamins E and C were decreased in patients with alcoholic liver disease as compared to controls.

CONCLUSIONS

Our observations may be due to increased demands of the same or increased utilization.

Effects of 2,4-D and its metabolite 2,4-dichlorophenol on antioxidant enzymes and level of glutathione in human erythrocytes

The effects of in vitro exposure of human erythrocytes to different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and its metabolite 2,4-dichlorophenol (2,4-DCP) were studied. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the level of reduced glutathione (GSH) were determined. The activity of erythrocyte superoxide dismutase SOD decreased with increasing dose of 2,4-D and 2,4-DCP, while glutathione peroxidase activity increased. 2,4-D (500 ppm) decreased the level of reduced glutathione in erythrocytes by 18% and 2,4-DCP (250 ppm) by 32%, respectively, in comparison with the controls. These results lead to the conclusion that in vitro administration of herbicide-2,4-D and its metabolite 2,4-DCP causes a decrease in the level of reduced glutathione in erythrocytes and significant changes in antioxidant enzyme activities. Comparison of the toxicity of 2,4-D and 2,4-DCP revealed that the most prominent changes occurred in human erythrocytes incubated with 2,4-DCP.

Oxidative damage in alcoholic liver disease

OBJECTIVE

The metabolic effects of alcohol are due both to its direct action and to that of its first metabolite, and can also be connected with the changes in redox state. Differences in ethanol distribution, bioavailability and hepatic metabolism can provide insight into the protective and predisposing factors in alcoholism, as well as gender differences of alcohol toxicity. Oxidative stress occurs following various conditions of ethanol consumption.

DESIGN

Twenty-six Caucasian patients with alcoholism and 32 healthy, abstinent controls of both sexes were investigated with special regard to reduction-oxidation status and ad hoc free-radical-antioxidant balance.

METHOD

Plasma free SH-group concentration, H-donating ability, and reducing power property were measured by simple spectrophotometric methods. Total scavenger capacity was determined by a newly developed chemiluminometric method in plasma and erythrocytes.

RESULTS

Alcoholics showed a decrease of free SH-group concentration, hydrogen-donating ability and an increase of reducing power property in plasma. A decreased total scavenger capacity of erythrocytes and plasma of alcoholic patients, combined with gender differences, could be detected.

CONCLUSIONS

Alcoholic dependence causes gradual exhaustion of the antioxidant capacity of erythrocytes, therefore this non-invasive measurement may be useful as a follow-up of the evolution of alcoholic liver disease. The results also suggest a gender susceptibility of alcohol toxicity.

Increased lipid and protein oxidation and DNA damage in patients with chronic alcoholism

Increased oxidative stress has been speculated to be one possible mechanism of ethanol toxicity. This study evaluates malondialdehyde (MDA) and protein carbonyl content in serum as markers of oxidative stress and DNA damage in lymphocytes in the same patients with chronic alcoholism. Patients with chronic alcoholism showed a significant increase in MDA levels and protein carbonyl content of their serum as compared with non-alcoholic control subjects. Increases in endogenous and H2O2-induced DNA damage were also observed in lymphocytes of patients with chronic alcoholism. In addition, there were significant correlations between endogenous and H2O2-induced DNA damage and serum MDA or protein carbonyl content in patients with chronic alcoholism. These results clearly indicate the presence of oxidative stress in patients with chronic alcoholism.