Abnormality in membrane fatty acid compositions of cells measured on erythrocyte in alcoholic liver disease

Fatty acid composition of the erythrocyte membrane and risk of hepatocellular carcinoma in cirrhotic patients

BACKGROUND

Disturbances in fatty acid (FA) metabolism have been reported in cirrhosis, but the role of FAs in the development of hepatocellular carcinoma (HCC) is still unclear. Biomarkers are a promising means to explore the associations between exogenous intake or endogenous production of FAs and cancer risk.

AIM

To estimate the relationship between fatty acid content in erythrocyte membranes and HCC risk in cirrhotic patients METHODS: The "CiRCE" case-control study recruited cirrhotic patients from six French hospitals between 2008 and 2012. Cases were cirrhotic patients with HCC (n = 349); controls were cirrhotic patients without HCC at inclusion (n = 550). FA composition of phospholipids in erythrocyte membranes was determined by high performance gas chromatography. Odds ratios for HCC risk according to FA concentrations were estimated with multivariable logistic regression.

RESULTS

HCC patients were older and more often men (P < 0.001). In both groups, saturated FAs represented more than 39% of all FAs in erythrocyte membranes, mono-unsaturated FAs around 14%, and polyunsaturated FAs around 46%. High levels of C15:0 + C17:0, C20:1 n-9, C18:2 n-6 and C20:2 n-6 were associated with higher risk of HCC. The levels of C18:0 and C20:4 n-6 were lower in HCC cases than in controls.

CONCLUSIONS

The FA composition of erythrocyte membranes differed according to the presence of HCC with higher levels of saturated FAs, linoleic and eicosadienoic acids, and lower levels of stearic and arachidonic acids. These alterations may reflect particular dietary patterns and/or altered FA metabolism. Further investigations are warranted.

The implementation of drug reposition for alcoholic hepatitis based on a sub-pathway integration strategy

Background

Alcoholic hepatitis (AH) is one of the most severe forms of liver disease. The therapies which are currently available are not entirely effective, and thus novel therapies are urgently needed. However, the development of these novel therapies is limited due to incomplete information about the molecular mechanisms involved in AH.

Methods

The microarray data (GSE28619) was downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between the AH and the control samples were identified using the significant analysis of microarrays (SAM) method. Metabolic sub-pathways were identified using the SubpathwayMiner R package. Cell Counting Kit-8 (CCK-8) was used to evaluate the cell viability of AML-12 cells treated with different concentrations of ethanol or riboflavin. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were employed to show the hepatocyte function.

Results

A total of 1,041 genes were determined to be expressed differentially. We then identified 11 metabolic sub-pathways that could be involved in the development of AH. This was followed by a final integrated analysis of the sub-pathways involved in AH as well as the sub-pathways involved in the drug-affected cases. The final integration results led to the identification of 64 small molecular drugs. A potential novel drug (riboflavin) involved in the fatty acid metabolism pathway was identified for further investigation. Riboflavin at the 60 nM for 24 h could reverse ethanol-induced AML-12 cell injury and could markedly decrease ALT and AST activity. The decrease in the activities of these two enzymes was observed in a dose-dependent manner when it was compared to ethanol alone, which suggests that riboflavin has a protective effect against liver cell injury caused by alcoholism.

Conclusions

To summarize, the candidate agents which are identified in the present study might give practitioners insight into the development of novel therapeutic approaches for AH.

OMEGA-3 Interventions in Alcohol Dependence and Related Outcomes: A Systematic Review and Propositions

BACKGROUND

Pharmacological treatment for alcohol dependence has only three approved drugs: disulfiram, naltrexone and acamprosate. The effects of these drugs are, however, limited, presenting several side effects and a modestly higher efficacy compared to placebo. The administration of omega-3 might bring new perspectives to relapse prevention.

METHODS

This systematic review aimed to analyze the available literature, compiling the studies that used omega-3 to prevent relapse in alcohol dependents.

RESULTS

The databases used were PubMed and Web of Science. We identified 2,231 studies and only five articles addressed the administration of omega-3 and alcoholism. Preclinical studies evaluating the effects of PUFAs related to chronic alcohol administration showed improvements in behavioral, cellular and molecular levels. The clinical trial yielded inconclusive results.

CONCLUSION

Despite the reduced number of studies, omega-3 interventions seem to be promising for controlling issues related to alcohol dependence.

The effects of polyunsaturated fatty acids in alcohol dependence treatment--a double-blind, placebo-controlled pilot study

Background

The lipid fraction of cell membranes consists of polyunsaturated fatty acids (PUFAS), and chronic alcohol use alters it, modifying its permeability, what might contribute for the dysfunctional metabolism observed in the central nervous system of alcohol dependent patients. Therefore, the supplementation of PUFAS can be an important adjuvant in alcoholism treatment.

Methods

This was a placebo controlled, double blind, randomized study where, 80 alcohol dependent patients, according to DSM-IV, were allocated in four groups with 20 patient each: 'PUFAS', 'Naltrexone', 'Naltrexone + PUFAS' and 'Placebo'. Those substances were administered for 90 days and scales were applied to assess patients craving (OCDS) and alcohol dependence severity (SADD) at baseline and after 90 days. PUFAS serum levels were assessed before and after treatment by high performance liquid chromatography assay.

Results

Forty-three patients completed the trial. There was a significant improvement over time on drinking days, SADD and OCDS scores in all groups (p < 0.001). The drinking days comparison between groups did not show statistical significant difference. The same effect was observed for compulsion (OCDS) and severity of dependence scale (SADD). The serum levels of PUFAS increased in all the supplemented groups after treatment, although not significantly.

Conclusions

The oral supplementation of 2 g PUFAS for 3 months did not significantly differ from placebo in reducing the amount of alcohol ingestion, or OCDS and SADD scores in a group of alcohol dependent patient.

Trial registration

NCT01211769

Alterations in the erythrocyte plasma membranes in patients with alcohol-induced liver cirrhosis - preliminary results

INTRODUCTION

Conformations of membrane proteins, membrane fluidity of erythrocytes in patients with AILC were studied with the use of electron paramagnetic resonance and spectrophotometric methods. The concentration of substances reacting with thiobarbituric acid was also determined. The aim of the study was to recognize the nature, level and causes of changes in the structure of erythrocytary membrane observed in erythrocytes of patients compared to erythrocytes from healthy controls.

MATERIAL AND METHODS

SPIN LABELS: MSL and ISL binding covalently to thiol groups of membrane cytoskeleton proteins were used to analyse modifications occurring in erythrocytary membrane proteins. Doxyl derivatives of fatty acids: 5-DS, 12-DS and 16-DS binding hydrophobically to erythrocytary membrane were used as spin labels for the analysis of erythrocyte membrane lipid fluidity.

RESULTS

Modification of membrane cytoskeleton proteins and increase of membrane lipids fluidity were observed in erythrocytes of the investigated patients. An increase of the concentration of substances reacting with thiobarbituric acid was also confirmed in the erythrocytes of AILC patients.

CONCLUSIONS

Observed disorders in the structure of erythrocyte cytoskeleton proteins in patients, which might developed as a consequence of oxidative stress may be conformation changes in the structure of proteins which affect membrane cytoskeleton. The differences in the structure of membrane proteins could be associated with an increase in membrane lipids fluidity. Increased fluidity of erythrocyte membrane may be a result of disorders in protein-lipid interaction or membrane lipid peroxidation activity.

Different effects of acute and chronic ethanol on LPS-induced cytokine production and TLR4 receptor behavior in mouse peritoneal macrophages

Both binge and chronic heavy drinking can adversely affect the immune system, but the effects seem to be at least partly dependent on the manner of ethanol (EtOH) consumption. Previous study results from several labs have clearly demonstrated that acute administration of EtOH interferes with innate immune responses. Specifically, EtOH has a general inhibitory effect on cytokine and chemokine production induced by various Toll-like receptor (TLR) ligands, and it suppresses signaling on several levels along the TLR signaling pathways. However, it is not clear whether chronic exposure to ethanol has the same effects or not. The purpose of this study was to investigate the difference between the effect of chronic versus acute EtOH exposure on LPS-induced cytokine production and clustering of components of the TLR4 complex, which is an important early signaling event. Some groups of mice received acute EtOH by oral gavage using our binge drinking model and/or chronic administration of EtOH at 20% (w/v) in the drinking water as the sole liquid source for 4 wk. The cellular distribution of CD14 and TLR4 were studied by confocal microscopy following exposure of peritoneal cells to LPS locally in vivo, and cytokine production in peritoneal fluid and serum was measured by ELISA after LPS injection via a tail vein. Chronic EtOH exposure did not consistently cause significant changes in LPS-induced cytokine production. However, mice previously exposed to chronic EtOH treatment became partially resistant to the suppressive effects of acute EtOH administration with regard to cytokine production. As we have reported previously, acute EtOH treatment suppressed the LPS-induced clustering of TLR4 and CD14 in peritoneal macrophages. However, peritoneal cells from mice treated with chronic EtOH exhibited a greater amount of intracellular expression of CD14 instead of CD14/TLR4 clustering on the membrane following LPS exposure. The results demonstrate different effects of chronic versus acute EtOH treatment on LPS-induced cytokine production in mice. Partial tolerance to the effect of acute EtOH administration caused by chronic EtOH treatment suggests a compensatory mechanism is induced by chronic EtOH administration. Acute EtOH exposure acts probably by disrupting the receptor clustering following LPS recognition, whereas adaptations induced by chronic EtOH treatment seem to involve alteration of LPS receptor expression.

Screening of differential serum proteins in patients with hepatic fibrosis

AIM: To compare and analyze the expression difference of proteins between hepatic fibrosis serum and normal human serum and to identify potential serum markers for human hepatic fibrosis.

METHODS: Serum samples were collected from 6 healthy subjects and 6 patients with hepatic fibrosis following normal protocols. The serum samples of these two groups were mixed into one respectively of equal volume. Albumin and IgG removal were carried out and serum total proteins were extracted. 2-DE was used to isolate the total proteins using pH 4-7 L, 18 cm IPG strip, and SDS-PAGE. Silver nitrate stain was applied afterwards. ImageMaster 2D Platinum Softwared (Version 5) was employed to analyze the 2-DE results. ELISA was adopted to verify the expression changes of some differential proteins.

RESULTS: The 2-DE matching rate was 89.58% between the two groups. From the two groups, 517 differential protein spots were identified, among which 24 with differential expression above three times were singgled out and MALDI-TOF-MS analysis was carried out on them. Eight proteins were identified, including transferring, apolipoprotein A-IV, T-cell receptor b, haptoglobin, serum albumin and serum albumin precursor. Up-regulated expression was observed in 3 proteins and down-regulated expression in 5 proteins in the hepatic fibrosis serum group. As compared with that in normal serum, haptoglobin and apolipoprotein A-IV expression were down-regulated in hepatic fibrosis serum, which was consistent with the results of 2-DE.

CONCLUSION: Compared with the normal subject group, the serum in the hepatic fibrosis group showed differential expression in protein profile. The proteins of differential expression are expected to be the serum markers for hepatic fibrosis.

The role of polyunsaturated fatty acids (PUFAs) in development, aging and substance abuse disorders: review and propositions

The polyunsaturated fatty acids (PUFAs), especially omega-3 and -6, play an important role in the functioning of membranes. Therefore, changes in their physical properties might entail impairment of the neurotransmission between cells. Studies emphasize the importance of omega-3 intakes, but they also highlight the need of a balance between omega-6 and -3, whose ideal ratio should be 4:1. The Western diet has very high amounts of saturated fat and omega-6, which might contribute, at least partially, to physiopathologies and high incidence as well as prevalence of psychiatric and neurodegenerative diseases. This narrow review aimed at systematizing the studies on the importance of PUFAs in some particular cases, that is, the extremes of life: pre- and post-natal development, and cognitive aging. Additionally, it aimed at studying the association between PUFAs and substance abuse disorders. We used the databases LILACs, MEDLINE and PUBMED.

Effect of ethanol and thermally oxidized sunflower oil ingestion on phospholipid fatty acid composition of rat liver: protective role of Cuminum cyminum L

AIM

The current study was undertaken to assess the effect of ethanol and thermally oxidized sunflower oil ingestion on liver phospholipid fatty acids and the protective role of Cuminum cyminum L.

METHODS

Ethanol was administered at a level of 20% and thermally oxidized sunflower oil at a level of 15% for 45 days. C. cyminum was administered at a dosage of 250 mg/kg body weight for 45 days. We investigated the changes in the liver phospholipid fatty acid composition.

RESULTS

Ethanol and thermally oxidized sunflower oil administration modifies the fatty acid composition and the analysis of fatty acids showed that there was a significant increase in the concentrations of 16:0, 16:1, 18:0, 18:1 and 18:2, whereas the concentration of 20:4 was significantly decreased. The concentrations of 16:0, 16:1, 18:0, 18:1 and 20:4 were near normal in cumin-treated rats.

CONCLUSION

The present investigation shows that cumin prevents the changes in the composition of fatty acids, which were produced by ethanol and thermally oxidized oil.

Alcoholic muscle disease and biomembrane perturbations (review)

Excessive alcohol ingestion is damaging and gives rise to a number of pathologies that influence nutritional status. Most organs of the body are affected such as the liver and gastrointestinal tract. However, skeletal muscle appears to be particularly susceptible, giving rise to the disease entity alcoholic myopathy. Alcoholic myopathy is far more common than overt liver disease such as cirrhosis or gastrointestinal tract pathologies. Alcohol myopathy is characterised by selective atrophy of Type II (anaerobic, white glycolic) muscle fibres: Type I (aerobic, red oxidative) muscle fibres are relatively protected. Affected patients have marked reductions in muscle mass and impaired muscle strength with subjective symptoms of cramps, myalgia and difficulty in gait. This affects 40-60% of chronic alcoholics (in contrast to cirrhosis, which only affects 15-20% of chronic alcohol misuers).Many, if not all, of these features of alcoholic myopathy can be reproduced in experimental animals, which are used to elucidate the pathological mechanisms responsible for the disease. However, membrane changes within these muscles are difficult to discern even under the normal light and electron microscope. Instead attention has focused on biochemical and other functional studies. In this review, we provide evidence from these models to show that alcohol-induced defects in the membrane occur, including the formation of acetaldehyde protein adducts and increases in sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase (protein and enzyme activity). Concomitant increases in cholesterol hydroperoxides and oxysterol also arise, possibly reflecting free radical-mediated damage to the membrane. Overall, changes within muscle membranes may reflect, contribute to, or initiate the disturbances in muscle function or reductions in muscle mass seen in alcoholic myopathy. Present evidence suggest that the changes in alcoholic muscle disease are not due to dietary deficiencies but rather the direct effect of ethanol or its ensuing metabolites.

Fatty acid profile in skeletal muscle of the rat in response to acute (2.5 hours) and prolonged (6 weeks) ethanol-dosage

We tested the hypothesis that phospholipids are altered in skeletal muscles of rats exposed to ethanol for either acute (2.5 hours) or prolonged (6 weeks) periods. In acute studies, rats were dosed with saline (0.15 mmol/l; controls) or ethanol (75 mmol/kg body weight; treated). There were four groups: (A) saline (control); (B) cyanamide (an aldehyde dehydrogenase inhibitor); (C) ethanol; and (D) cyanamide + ethanol. In prolonged studies, two groups of rats were fed liquid diets containing 35% of total dietary energy as either glucose [group (E)] or ethanol [group (F)]. At the end of the treatments, membrane phospholipids were measured in soleus (Type I fibre-predominant) and plantaris (Type II fibre-predominant) muscle. In acute studies, ethanol alone [(A) vs. (C)] and cyanamide + ethanol [(A) vs. (D)] significantly increased 18 : 2 in plantaris (p < 0.05), whereas in soleus none of the treatments had any effect on the phospholipids. In prolonged studies [(E) vs. (F)], there were decreases in 16 : 0 (p < 0.05) and 18 : 1 (p < 0.01) and increases in 18 : 2 (p < 0.001) in plantaris. In soleus, decreases in 18 : 1 (p < 0.05) and increases in 18 : 2 (p < 0.01) occurred. In conclusion, alterations in the proportions of 16 : 0, 18 : 1 and 18 : 2 provide evidence of an altered membrane domain which may contribute to the pathogenesis of alcohol-induced muscle disease. Changes due to prolonged exposure are more profound than those in acute exposure and the preferential effects in Type II plantaris may reflect the greater susceptibility of this muscle to alcohol.

Ethanol- and Fe(+2)-induced membrane lipid oxidation is not additive in developing chick brains

In order to study the effects of exogenous EtOH and/or Fe(+2) on membrane lipid peroxidation, exogenous EtOH, FeCl(2), FeCl(2) & EtOH, NaCl and NaCl & EtOH were injected into fertile chicken eggs. Controls were either shams or injected with saline. These injections were made at 0 days or 0-2 days of development and tissue removed at stage 37 (11 days of development). Embryonic exposure to exogenous EtOH and/or Fe(+2) promoted decreased brain mass, decreased levels of brain membrane polyunsaturated fatty acids, elevated levels of brain lipid hydroperoxides, and elevated levels of Fe(+2) within embryonic brain and liver. These alterations were more severe in triple-injected embryos (E0-2/E11) as compared to single-injected embryos (E0/E11). While exogenous treatments of either EtOH and/or FeCl(2) promoted increased levels of endogenous brain Fe(+2), the effects were not additive. These observations are consistent with the hypothesis that embryonic exposure to exogenous EtOH and/or Fe(+2) promotes brain membrane lipid peroxidation.

Does ethanol metabolism affect erythrocyte hemolysis?

The effects of ethanol and acetaldehyde on the hemolytic stability of rabbit erythrocytes have been compared. Incubation of normal erythrocytes with ethanol facilitated both acidic and oxidative hemolysis and increased the percentages of cells that were hemolyzed at maximal rate. Acetaldehyde exerted a similar destabilizing effect on erythrocytes only in the case of oxidative hemolysis. The destabilizing effect of ethanol was observed in catalase-inactivated erythrocytes under acidic, but not oxidative, hemolysis conditions. It is concluded that the destabilizing effect of unmetabolized ethanol occurs under conditions of acidic hemolysis, whereas the destabilizing effect of the oxidation of ethanol to acetaldehyde takes place only under the conditions of oxidative hemolysis.

Alpha-tocopherol and gamma-tocopherol attenuate ethanol-induced changes in membrane fatty acid composition in embryonic chick brains

BACKGROUND

This project investigated whether or not EtOH-induced reductions in the levels of long-chain polyunsaturated membrane fatty acids could be attenuated by exogenous exposure to either alpha-tocopherol, gamma-tocopherol, or diallyl sulfide (DAS).

METHODS

At 0 days of development, fertile chicken eggs were injected with a single dose of either saline supplemented with various concentrations of EtOH, alpha- or gamma-tocopherol and EtOH, or DAS and EtOH. At 18 days of development, brains were isolated and subjected to membrane analyses.

RESULTS

When exposed to EtOH, concentrations ranging from 0-60.50 microm/Kg egg, dose-dependent decreases in the levels of brain 18:0, 18:1 (n-9), 18:2 (n-6), 18:3 (n-3), and 20:4 (n-6) were observed. These ethanol-induced changes in membrane fatty acid composition correlated with ethanol-induced reductions in brain mass, brain protein levels, acetylcholine esterase (AChE) activities and correlated with increased lipid hydroperoxide levels. Exposure to either 2.5 microm alpha-tocopherol/Kg egg and 6.050 mm EtOH/Kg egg, or 2.5 microm alpha-tocopherol/ Kg egg and 6.050 mm EtOH/Kg egg attenuated EtOH-induced changes in membrane fatty acid composition, brain mass, brain protein levels, AChE activities, and lipid hydroperoxide levels. Embryonic exposure to the cytochrome p450-2E1 inhibitor, diallyl sulfide (DAS), also attenuated EtOH-induced decreases in long-chain, unsaturated membrane fatty acids. However, embryonic exposure to DAS promoted abnormally low brain mass.

CONCLUSION

EtOH-induced reductions in the levels of brain long-chain polyunsaturated fatty acid are caused by lipid peroxidation.

Alcohol abuse, alcoholism, and damage to the immune system--a review

Chronic alcohol abuse exacts a major social and medical toll in the United States and other Western countries. One of the least appreciated medical complications of alcohol abuse is altered immune regulation leading to immunodeficiency and autoimmunity. The consequences of the immunodeficiency include increased susceptibility to bacterial pneumonia, tuberculosis, and other infectious diseases. In addition, the chronic alcoholic often has circulating autoantibodies, and recent investigations indicate that the most destructive complications of alcoholism, such as liver disease and liver failure, may have a component of autoimmunity. Current research on altered cytokine balance produced by alcohol is leading to new insights on the regulation of the immune system in the chronic alcoholic. There is also recent development of exciting new techniques designed to improve or restore immune function by manipulation of cytokine balance. Although much remains to be learned, both in the abnormalities produced by alcohol and in the techniques to reverse those abnormalities, current progress reflects a rapidly improving understanding of the basic immune disorders of the alcoholic.

Relationship between platelet membrane lipid compositions and platelet aggregability in alcoholic liver disease

We studied the relationship between changes in platelet aggregability and platelet membrane lipid in alcoholic liver disease. The maximal rate of ADP-induced platelet aggregation was significantly increased in the alcoholic liver disease group than in the control group. No significant difference was observed in the maximal rate of collagen-induced platelet aggregation. However, a lag time required for the start of platelet aggregation was significantly shortened in the alcoholic liver disease group, indicating increased platelet aggregability. Results of the platelet aggregation test suggested that alcoholic liver disease patients have their platelet aggregation affected by the abnormality of prostaglandin metabolism. The alcoholic liver disease group was further divided into two subgroups: the hyperaggregation group and the unchanged aggregation group. Both free cholesterol and phospholipid in the platelet membrane were significantly increased in the alcoholic liver disease group. In phospholipid compositions, phosphatidylserine plus phosphatidylinositol were significantly decreased in the alcoholic liver disease group, whereas a significant decrease in phosphatidylserine plus phosphatidylinositol was observed in the hyperaggregation group of alcoholic liver disease. Analysis of fatty acid compositions of platelet membrane showed significantly decreased palmitic acid in the alcoholic group. There was no significant change of arachidonic acid, which directly affects platelet aggregation. Eicosapentaenoic acid significantly decreased in the alcoholic liver disease group, but there was no difference in docosahexaenoic acid. Meanwhile, the thrombogenic index, calculated from the fatty acids of platelet membrane, showed no difference between the alcoholic liver disease group and the control group. However, the thrombogenic index was significantly increased in the hyperaggregation group than in the unchanged aggregation group. These data suggested that platelet aggregation is affected by not only a change in arachidonic acid, but also changes in fatty acid compositions of the platelet membrane.

Effects of supplementation with unsaturated fatty acids on plasma and membrane lipid composition and platelet function in patients with cirrhosis and defective aggregation

BACKGROUND/AIMS

Defective platelet aggregation and reduced platelet production of thromboxane A2, a metabolite of arachidonic acid, are common findings in patients with cirrhosis. We evaluated the effects of dietary supplementation with two combinations of unsaturated fatty acids on platelet function and plasma and membrane fatty acids in patients with liver cirrhosis.

METHODS

In a double-blind study, 15 patients with cirrhosis and defective aggregation were randomized to receive a 6-week supplementation with gamma-linolenic and linoleic acid (1 g/day of each fatty acid) or with oleic acid and linoleic acid (groups GLA and OA, respectively).

RESULTS

Under baseline conditions, patients showed elevated concentrations of monounsaturated fatty acids and a reduction in polyunsaturated fatty acids. The product/precursor ratios for delta6 and delta5 desaturases, two key enzymes in the pathway leading to arachidonic acid, were significantly reduced in the group of patients. In the GLA group, a significant increase in the levels of dihomo-gamma-linolenic acid (20:3omega6) was observed in plasma and membranes, together with a parallel decrease in the 20:4/20:3omega6 ratio after supplementation. No significant changes were observed in the OA group. The levels of arachidonic acid did not change significantly in either group of patients. Platelet aggregation to collagen was unchanged in the GLA group, but significantly improved in the OA group.

CONCLUSIONS

These results show that supplementation with precursors of arachidonic acid is ineffective in elevating plasma or membrane arachidonate levels and does not improve platelet aggregation, suggesting that synthesis of arachidonic acid through the delta5 desaturase cannot be correspondingly activated or that incorporation/retention of the produced fatty acid into lipids is impaired. The increased platelet aggregation in the OA group is likely to be explained by the effect of oleic acid contained in the diet, the effects of which may have been counteracted by the elevation in 20:3omega6, a source of anti-aggregatory prostanoids, in the GLA group.