Ethanol exposure causes a decrease in docosahexaenoic acid and an increase in docosapentaenoic acid in feline brains and retinas

Impact of health and lifestyle food supplements on periodontal tissues and health

According to the new classification, periodontitis is defined as a chronic multifactorial inflammatory disease associated with dysbiotic biofilms and characterized by progressive destruction of the tooth-supporting apparatus. This definition, based on the current scientific evidence, clearly indicates and emphasizes, beside the microbial component dental biofilm, the importance of the inflammatory reaction in the progressive destruction of periodontal tissues. The idea to modulate this inflammatory reaction in order to decrease or even cease the progressive destruction was, therefore, a logical consequence. Attempts to achieve this goal involve various kinds of anti-inflammatory drugs or medications. However, there is also an increasing effort in using food supplements or so-called natural food ingredients to modulate patients' immune responses and maybe even improve the healing of periodontal tissues. The aim of this chapter of Periodontology 2000 is to review the evidence of various food supplements and ingredients regarding their possible effects on periodontal inflammation and wound healing. This review may help researchers and clinicians to evaluate the current evidence and to stimulate further research in this area.

The thermodynamic soliton theory of the nervous impulse and possible medical implications

The textbook picture of nerve activity is that of a propagating voltage pulse driven by electrical currents through ion channel proteins, which are gated by changes in voltage, temperature, pressure or by drugs. All function is directly attributed to single molecules. We show that this leaves out many important thermodynamic couplings between different variables. A more recent alternative picture for the nerve pulse is of thermodynamic nature. It considers the nerve pulse as a soliton, i.e., a macroscopic excited region with properties that are influenced by thermodynamic variables including voltage, temperature, pressure and chemical potentials of membrane components. All thermodynamic variables are strictly coupled. We discuss the consequences for medical treatment in a view where one can compensate a maladjustment of one variable by adjusting another variable. For instance, one can explain why anesthesia can be counteracted by hydrostatic pressure and decrease in pH, suggest reasons why lithium over-dose may lead to tremor, and how tremor is related to alcohol intoxication. Lithium action as well as the effect of ethanol and the anesthetic ketamine in bipolar patients may fall in similar thermodynamic patterns. Such couplings remain obscure in a purely molecular picture. Other fields of application are the response of nerve activity to muscle stretching and the possibility of neural stimulation by ultrasound.

Dietary sources, current intakes, and nutritional role of omega-3 docosapentaenoic acid

Fish oils and long-chain omega-3 fatty acids are well recognized for their critical role in human diets. Docosapentaenoic acid (DPA, 22 : 5n-3) has always been a part of healthy nutrition, since infants obtain almost as much DPA as DHA from human milk. Fish oil supplements and ingredients, oily fish, and grass-fed beef can serve as the primary DPA sources for the general population. Although the DPA levels in fish oils are substantially lower than those of EPA and DHA, concentrated DPA products are now becoming commercially available, and DPA-based drugs are under development. Epidemiological studies show that similar to eicosapentaenoic (EPA, 20 : 5n-3) and docosahexaenoic (DHA, 22 : 6n-3) acids, DPA is linked to various improvements in human health, perhaps owing to its structural similarity to the other two molecules. Studies in mammals, platelets, and cell cultures have demonstrated that DPA reduces platelet aggregation, and improves lipid metabolism, endothelial cell migration, and resolution of chronic inflammation. Further, other in vivo and in vitro studies have shown that DPA can improve neural health. A human supplementation trial with 99.8% pure DPA suggested that it serves as a storage depot for EPA and DHA in the human body. Future randomized controlled human trials with purified DPA will help clarify its effects on human health. They may confirm the available evidence pointing to its nutritional and biological functions, unique or overlapping with those of EPA and DHA.

Genomic influences on alcohol problems in a population-based sample of young adults

AIMS

Alcohol problems (AP) contribute substantially to the global disease burden. Twin and family studies suggest that AP are genetically influenced, although few studies have identified variants or genes that are robustly associated with risk. This study identifies genetic and genomic influences on AP during young adulthood, which is often when drinking habits are established.

DESIGN

We conducted a genome-wide association study of AP. We further conducted gene-based tests, gene ontology analyses and functional genomic enrichment analyses to assess genomic factors beyond single variants that are relevant to AP.

SETTING

The Avon Longitudinal Study of Parents and Children, a large population-based study of a UK birth cohort.

PARTICIPANTS

Genetic and phenotypical data were available for 4304 participants.

MEASUREMENTS

The AP phenotype was a factor score derived from items from the Alcohol Use Disorders Identification Test, symptoms of DSM-IV alcohol dependence, and three additional problem-related items.

FINDINGS

One variant met genome-wide significance criteria. Four out of 22,880 genes subjected to gene-based analyses survived a stringent significance threshold (q < 0.05); none of these have been implicated previously in alcohol-related phenotypes. Several biologically plausible gene ontologies were statistically over-represented among implicated single nucleotide polymorphisms (SNPs). SNPs on the Illumina 550 K SNP chip accounted for ~5% of the phenotypical variance in AP.

CONCLUSIONS

Genetic and genomic factors appear to play a role in alcohol problems in young adults. Genes involved in nervous system-related processes, such as signal transduction and neurogenesis, potentially contribute to liability to alcohol problems, as do genes expressed in non-brain tissues.

Brain docosahexaenoic acid [DHA] incorporation and blood flow are increased in chronic alcoholics: a positron emission tomography study corrected for cerebral atrophy

OBJECTIVE

Chronic alcohol dependence has been associated with disturbed behavior, cerebral atrophy and a low plasma concentration of docosahexaenoic acid (DHA, 22∶6n-3), particularly if liver disease is present. In animal models, excessive alcohol consumption is reported to reduce brain DHA concentration, suggesting disturbed brain DHA metabolism. We hypothesized that brain DHA metabolism also is abnormal in chronic alcoholics.

METHODS

We compared 15 non-smoking chronic alcoholics, studied within 7 days of their last drink, with 22 non-smoking healthy controls. Using published neuroimaging methods with positron emission tomography (PET), we measured regional coefficients (K*) and rates (J(in)) of DHA incorporation from plasma into the brain of each group using [1-(11)C]DHA, and regional cerebral blood flow (rCBF) using [(15)O]water. Data were partial volume error corrected for brain atrophy. Plasma unesterified DHA concentration also was quantified.

RESULTS

Mean K* for DHA was significantly and widely elevated by 10-20%, and rCBF was elevated by 7%-34%, in alcoholics compared with controls. Unesterified plasma DHA did not differ significantly between groups nor did whole brain J(in), the product of K* and unesterified plasma DHA concentration.

DISCUSSION

Significantly higher values of K* for DHA in alcoholics indicate increased brain avidity for DHA, thus a brain DHA metabolic deficit vis-à-vis plasma DHA availability. Higher rCBF in alcoholics suggests increased energy consumption. These changes may reflect a hypermetabolic state related to early alcohol withdrawal, or a general brain metabolic change in chronic alcoholics.

Prenatal ethanol exposure increases brain cholesterol content in adult rats

Fetal alcohol syndrome is the most severe expression of the fetal alcohol spectrum disorders (FASD). Although alterations in fetal and neonate brain fatty acid composition and cholesterol content are known to occur in animal models of FASD, the persistence of these alterations into adulthood is unknown. To address this question, we determined the effect of prenatal ethanol exposure on individual phospholipid class fatty acid composition, individual phospholipid class mass, and cholesterol mass in brains from 25-week-old rats that were exposed to ethanol during gestation beginning at gestational day 2. While total phospholipid mass was unaffected, phosphatidylinositol and cardiolipin mass was decreased 14 and 43 %, respectively. Exposure to prenatal ethanol modestly altered brain phospholipid fatty acid composition, and the most consistent change was a significant 1.1-fold increase in total polyunsaturated fatty acids (PUFA), in the n-3/n-6 ratio, and in the 22:6n-3 content in ethanolamine glycerophospholipids and in phosphatidylserine. In contrast, prenatal ethanol consumption significantly increased brain cholesterol mass 1.4-fold and the phospholipid to cholesterol ratio was significantly increased 1.3-fold. These results indicate that brain cholesterol mass was significantly increased in adult rats exposed prenatally to ethanol, but changes in phospholipid mass and phospholipid fatty acid composition were extremely limited. Importantly, suppression of postnatal ethanol consumption was not sufficient to reverse the large increase in cholesterol observed in the adult rats.

Consumption of Chinese tea-flavor liquor improves circulating insulin levels without affecting hepatic lipid metabolism-related gene expression in Sprague-Dawley rats

Objective. To examine the effect of two Chinese liquors with quite different nonalcoholic components on insulin sensitivity, tissue polyunsaturated fatty acids (PUFA), and hepatic lipid metabolism in SD rats. Methods. Thirty-three SD rats were randomized into four groups and maintained in each treatment for 10 weeks: Chinese tea-flavor liquor (TFL, n = 9), traditional Chinese liquor (TCL, n = 8), ethanol control (EC, n = 8), and water control (WC, n = 8). Results. TFL significantly decreased plasma insulin (P = 0.009) and marginally decreased Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) (P = 0.05), compared with WC. Hepatic total and n-6 PUFA compositions were significantly decreased in TFL, TCL, and EC groups compared with WC group (P < 0.05). TFL significantly increased kidney n-6 PUFA (P = 0.05) and total PUFA (P = 0.039), compared with EC group. EC group showed significant higher gene expressions of acetyl-CoA carboxylase and steroid response element-binding protein (1c and 2), while there were no significant differences of these gene expressions in TFL or TCL group compared with WC. Conclusions. TFL has a beneficial effect on metabolic disorder in relation to improved circulating insulin levels without affecting hepatic lipid metabolism-related gene expressions in rats.

Neuroinflammatory pathways in binge alcohol-induced neuronal degeneration: oxidative stress cascade involving aquaporin, brain edema, and phospholipase A2 activation

Chronic binge alcohol exposure in adult rat models causes neuronal degeneration in the cortex and hippocampus that is not reduced by excitotoxic receptor antagonists, but is prevented by antioxidants. Neuroinflammatory (glial-neuronal) signaling pathways are believed to underlie the oxidative stress and brain damage. Based on our experimental results as well as increased knowledge about the pro-neuroinflammatory potential of glial water channels, we propose that induction of aquaporin-4 can be a critical initiating factor in alcohol's neurotoxic effects, through the instigation of cellular edema-based neuroinflammatory cascades involving increased phospholipase A2 activities, polyunsaturated fatty acid release/membrane depletion, decreased prosurvival signaling, and oxidative stress. A testable scheme for this pathway is presented that incorporates recent findings in the alcohol-brain literature indicating a role for neuroimmune activation (upregulation of NF-kappaB, proinflammatory cytokines, and toll-like receptors). We present the argument that such neuroimmune activation could be associated with or even dependent on increased aquaporin-4 and glial swelling as well.

Oxidative stress in anxiety and comorbid disorders

Anxiety disorders, depression, and alcohol use disorder are common neuropsychiatric diseases that often occur together. Oxidative stress has been suggested to contribute to their etiology. Oxidative stress is a consequence of either increased generation of reactive oxygen species or impaired enzymatic or non-enzymatic defense against it. When excessive it leads to damage of all major classes of macromolecules, and therefore affects several fundamentally important cellular functions. Consequences that are especially detrimental to the proper functioning of the brain include mitochondrial dysfunction, altered neuronal signaling, and inhibition of neurogenesis. Each of these can further contribute to increased oxidative stress, leading to additional burden to the brain. In this review, we will provide an overview of recent work on oxidative stress markers in human patients with anxiety, depressive, or alcohol use disorders, and in relevant animal models. In addition, putative oxidative stress-related mechanisms important for neuropsychiatric diseases are discussed. Despite the considerable interest this field has obtained, the detailed mechanisms that link oxidative stress to the pathogenesis of neuropsychiatric diseases remain largely unknown. Since this pathway may be amenable to pharmacological intervention, further studies are warranted.

Compartmental analysis of plasma and liver n-3 essential fatty acids in alcohol-dependent men during withdrawal

The mechanism by which chronic ethanol consumption reduces concentrations of long chain polyunsaturated (LCP) fatty acids (FA) in tissues of humans was investigated in alcohol-dependent (AD) men during early withdrawal and to a well-matched control group by fitting the concentration-time curves of d(5)-labeled n-3 FA from plasma and liver, which originated from an oral dose of d(5)-linolenic acid (d(5)-18:3n-3) ethyl ester to a compartmental model. Blood sampled over 168 h and a liver specimen obtained 96 h after isotope administration were analyzed for d(5)-18:3n-3, d(5)-20:5n-3, d(5)-22:5n-3, and d(5)-22:6n-3. Plasma 20:5n-3 and 22:5n-3 were lower in AD subjects, compared with controls (20:5n-3: -50%, 22:5n-3: -34%). Increased amounts of d(5)-18:3n-3 were directed toward synthesis of d(5)-20:5n-3 in AD subjects (P < .05). However, this effect was offset by larger amounts of 20:5n-3 lost from plasma (control: 2.0 vs. AD: 4.2 mg d(-1)). In livers of AD subjects, more d(5)-18:3n-3 and d(5)-22:5n-3 were utilized for synthesis of d(5)-20:5n-3 (+200%) and d(5)-22:6n-3 (+210%), respectively, than was predicted from plasma kinetics. Although, the potential to utilize linolenic acid for synthesis of LCP FA was greater in AD subjects compared with controls, heightened disappearance rates of 20:5n-3 reduced overall plasma concentrations of several endogenous n-3 LCP FA.

Prevention of alcoholic fatty liver and mitochondrial dysfunction in the rat by long-chain polyunsaturated fatty acids

BACKGROUND/AIMS

We reported that reduced dietary intake of polyunsaturated fatty acids (PUFA) such as arachidonic (AA,20:4n6,omega-6) and docosahexaenoic (DHA,22:6n3,omega-3) acids led to alcohol-induced fatty liver and fibrosis. This study was aimed at studying the mechanisms by which a DHA/AA-supplemented diet prevents alcohol-induced fatty liver.

METHODS

Male Long-Evans rats were fed an ethanol or control liquid-diet with or without DHA/AA for 9 weeks. Plasma transaminase levels, liver histology, oxidative/nitrosative stress markers, and activities of oxidatively-modified mitochondrial proteins were evaluated.

RESULTS

Chronic alcohol administration increased the degree of fatty liver but fatty liver decreased significantly in rats fed the alcohol-DHA/AA-supplemented diet. Alcohol exposure increased oxidative/nitrosative stress with elevated levels of ethanol-inducible CYP2E1, nitric oxide synthase, nitrite and mitochondrial hydrogen peroxide. However, these increments were normalized in rats fed the alcohol-DHA/AA-supplemented diet. The number of oxidatively-modified mitochondrial proteins was markedly increased following alcohol exposure but significantly reduced in rats fed the alcohol-DHA/AA-supplemented diet. The suppressed activities of mitochondrial aldehyde dehydrogenase, ATP synthase, and 3-ketoacyl-CoA thiolase in ethanol-exposed rats were also recovered in animals fed the ethanol-DHA/AA-supplemented diet.

CONCLUSIONS

Addition of DHA/AA prevents alcohol-induced fatty liver and mitochondrial dysfunction in an animal model by protecting various mitochondrial enzymes most likely through reducing oxidative/nitrosative stress.

Binge ethanol-induced neurodegeneration in rat organotypic brain slice cultures: effects of PLA2 inhibitor mepacrine and docosahexaenoic acid (DHA)

Using rat organotypic hippocampal-entorhinal cortical (HEC) slice cultures, we examined whether phospholipase A2 (PLA2) activity is involved in binge alcohol (ethanol)-induced neurodegeneration, and whether docosahexaenoic acid (DHA; 22:6n-3), a fish oil-enriched fatty acid that is anti-inflammatory in brain damage models, is neuroprotective. Assessed with propidium iodide and lactate dehydrogenase (LDH) leakage, neurodamage from ethanol (6 days 100 mM ethanol with four withdrawal periods) was prevented by the PLA2 pan-inhibitor, mepacrine. Also, ethanol-dependent neurodegeneration-particularly in the entorhinal region-was significantly ameliorated by DHA supplementation (25 microM); however, adrenic acid, a 22:4n-6 analog, was ineffective. Consistent with PLA2 activation, [(3)H] liberation was approximately fivefold greater in [(3)H]arachidonic acid-preloaded HEC slice cultures during ethanol withdrawal compared to controls, and DHA supplementation suppressed [(3)H] release to control levels. DHA might antagonize PLA2 activity directly or suppress upstream activators (e.g., oxidative stress); however, other DHA mechanisms could be important in subdueing ethanol-induced PLA2-dependent and independent neuroinflammatory processes.

Biochemical and biological functions of docosahexaenoic acid in the nervous system: modulation by ethanol

Docosahexaenoic acid (DHA, 22:6n-3), an n-3 fatty acid highly concentrated in the central nervous system, is essential for proper neuronal and retinal function. While a high level of DHA is generally maintained in neuronal membranes, inadequate supply of n-3 fatty acid or ethanol exposure leads to a significant loss of DHA in neuronal cells. The roles of DHA in neuronal signaling have been emerging. In this review, biological, biochemical and molecular mechanisms supporting the essential function of DHA in neuronal survival and development are described in relation to n-3 fatty acid depleting conditions.

Lifestyle-related factors in predementia and dementia syndromes

Cognitive decline and dementia have a deep impact on the health and quality of life of older subjects and their caregivers. Since the therapeutic options currently available have demonstrated limited efficacy, the search for preventive strategies for cognitive decline and dementia are mandatory. A possible role of lifestyle-related factors was recently proposed for age-related changes of cognitive function, predementia syndromes and the cognitive decline of degenerative (Alzheimer's disease [AD]) or vascular origin. At present, cumulative evidence suggests that vascular risk factors may be important in the development of mild cognitive impairment (MCI), dementia and AD. Moderate alcohol drinking has been proposed as a protective factor against MCI and dementia in several longitudinal studies, but contrasting findings also exist. The Mediterranean diet could therefore be an interesting model with which to further study the association between dietary patterns and cognitive functioning, given the suggested role of many components of this diet (monounsaturated fatty acids, polyunsaturated fatty acids, cereals and red wine) in contrasting cognitive impairment and dementia. The association between low education and predementia and dementia syndromes is supported by the majority of studies, but very few studies have investigated whether this association may be attributed with lifestyle factors that covary with education. Studies in the literature seem to identify in physical exercise one promising strategy in decreasing cognitive decline, but some of the limitations of these studies do not allow us to draw definite conclusions. At present, in older subjects, healthy diets, antioxidant supplements, the prevention of nutritional deficiencies, and moderate physical activity could be considered the first line of defense against the development and progression of predementia and dementia syndromes. However, in most cases, these were only observational studies, and results are awaited from large multicenter randomized clinical trials in older persons that may clarify the possible synergy, for example, between moderate exercise, physical activity and healthy Mediterranean diet on cognition in the elderly.

Alcohol consumption and fatty acid intakes in the 2001-2002 National Health and Nutrition Examination Survey

BACKGROUND

Alcohol consumption has the potential to affect dietary intakes of nutrients; however, little is known about fatty acid intakes among alcohol consumers in the U.S. population.

METHOD

We examined the relation between self-reported alcohol consumption and dietary fatty acid intake in 4,168 adults in the cross-sectional National Health and Nutrition Examination Survey 2001-2002. Fatty acid intake was determined from a single, interviewer-administered 24-hour recall. The adjusted, weighted mean level of dietary fatty acid intakes, as characterized by nutrient density, was calculated as grams of fatty acid per 1,000 kcal of energy consumed according to average daily alcohol consumption and binge-drinking episodes.

RESULTS

Energy intake showed a significant increasing trend across alcohol consumption categories in both genders and binge-drinking categories in men. Women binge drinkers also showed a higher energy intake compared with nonbinge drinkers. Among men, decreased nutrient densities of saturated, monounsaturated, polyunsaturated, linoleic, and alpha-linolenic acids were associated with increasing alcohol consumption. Binge-drinking men but not women had significantly decreased intakes of total saturates, monounsaturates, polyunsaturates and linoleic, alpha-linolenic, eicosapentaenoic, and docosahexaenoic acid. When alcohol energy was excluded from calculation of nutrient densities, the results were similar to those with alcohol energy included, except that total saturated and monounsaturated fatty acid differences were no longer significant. In addition, there was an inverse relationship among men between binge-drinking frequency and total polyunsaturates, linoleic, alpha-linolenic, and eicosapentaenoic acids.

CONCLUSION

Our cross-sectional results suggest that alcohol consumption may impact the dietary intake of essential fatty acids (EFAs). Given the public health importance of both alcohol consumption and intakes of EFAs, prospective studies of the relation should be considered.

Modulation of lipid rafts by Omega-3 fatty acids in inflammation and cancer: implications for use of lipids during nutrition support

Current understanding of biologic membrane structure and function is largely based on the concept of lipid rafts. Lipid rafts are composed primarily of tightly packed, liquid-ordered sphingolipids/cholesterol/saturated phospholipids that float in a sea of more unsaturated and loosely packed, liquid-disordered lipids. Lipid rafts have important clinical implications because many important membrane-signaling proteins are located within the raft regions of the membrane, and alterations in raft structure can alter activity of these signaling proteins. Because rafts are lipid-based, their composition, structure, and function are susceptible to manipulation by dietary components such as omega-3 polyunsaturated fatty acids and by cholesterol depletion. We review how alteration of raft lipids affects the raft/nonraft localization and hence the function of several proteins involved in cell signaling. We focus our discussion of raft-signaling proteins on inflammation and cancer.

The effect of maternal smoking and ethanol on fatty acid transport by the human placenta

The role of the placenta in controlling the supply of fatty acids to the fetus was investigated in term placentas from non-smokers (n5), smokers (>ten cigarettes/d;n5) and after addition of ethanol at 2 mg/ml (n4). The maternal side was of the placenta was perfusedex vivofor 90 min with a physiological mixture of fatty acids and fatty acid:human albumin ratio. There was no effect of smoking on the transfer of linoleic (LA, 18 : 2n-6), α-linolenic (αLN, 18 : 3n-3), arachidonic (AA, 20 : 4n-6) or docosahexaenoic acid (DHA, 22 : 6n-3), expressed per perfused area (calculated from H218O exchange). However, the presence of ethanol in the perfusate at a concentration of 2 mg/ml significantly reduced (P<0·01) the absolute rate of transfer of the twon-3 polyunsaturated fatty acids, αLN and DHA. This specific effect of ethanol on αLN and DHA also resulted in an altered selectivity for transfer of individual fatty acids. In the non-smoking control group the placenta selectively transferred polyunsaturated fatty acids to the fetus in the order DHA>AA>αLN>LA. The order of selectivity was unaltered in placentas from smokers, but the addition of ethanol to the perfusion medium altered the order of selectivity to AA>αLN>LA>DHA. The presence of ethanol in the perfusate was also associated with a significant reduction (P<0·05) in the clearance of H218O. These results suggest that the presence of ethanol at a concentration of 2 mg/ml may reduce the availability of polyunsaturated fatty acids to the developing fetus.

Inhibition of phosphatidylserine biosynthesis in developing rat brain by maternal exposure to ethanol

Phosphatidylserine (PtdSer), major acidic phospholipids in neuronal membranes, participate in important cell signaling processes. The PtdSer in brain is highly enriched with docosahexaenoic acid (DHA; 22:6n-3), and the DHA status or ethanol exposure has been shown to influence the PtdSer level. This study shows that ethanol exposure during prenatal and developmental period significantly attenuates microsomal PtdSer biosynthetic activities and reduces PtdSer, particularly 18:0, 22:6-PtdSer, in developing rat brain cortices. Brain microsomes were incubated with deuterium labeled exogenous substrates in vitro and the products formed were detected by reversed phase HPLC-electrospray ionization mass spectrometry (ESI-MS). These in vitro bioassays showed that 1-stearoyl-2-docosahexaenoyl (18:0, 22:6) species is the best substrate for PtdSer synthesis from both phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn). The PtdSer biosynthetic activity of brain, especially for 18:0, 22:6-PtdSer production, was hampered significantly by maternal exposure to ethanol. PtdSer levels were consistently reduced significantly in brain cortices of the pups from ethanol-exposed dams, due mainly to the depletion of 18:0, 22:6-PtdSer. The mRNA expression of PtdSer synthase 1 (PSS1) and PtdSer synthase 2 (PSS2) was not reduced by ethanol. Similarly, the PSS1 enzyme level did not change after ethanol exposure but PSS2 could not be probed with the antibody available currently. Degradation of PtdSer by mitochondrial PtdSer decarboxylation was not enhanced but also inhibited. Taken together, attenuated PtdSer biosynthetic activities are largely responsible for the PtdSer reduction observed in developing rat brains after maternal exposure to ethanol.

Alcohol-Induced Lipid and Morphological Changes in Chick Retinal Development

BACKGROUND

Alcohol exposure causes alterations in the lipid content of different organs and a reduction of long-chain fatty acids. During embryo development, the central nervous system is extremely vulnerable to the teratogenic effects of alcohol, and the visual system is particularly sensitive.

METHODS

White Leghorn chick embryos were injected with 10- and 20-microl alcohol doses into the yolk sac at day 6 of incubation. The lipid composition of the retina was analyzed in embryos at day 7 of incubation (E7), E11, E15, and E18. The percentages of phospholipids, free cholesterol, esterified cholesterol, diacylglycerides, and free fatty acids were estimated by using an Iatroscan thin layer chromatography flame ionization detector. Gas chromatography and mass spectrometry were used to determine fatty acid composition. The morphological study was performed at E7, E11, and E19 by means of semithin and immunohistochemical techniques.

RESULTS

In the retina, alcohol causes the total lipid content to change, with a remarkable increase in free cholesterol and a dramatic decrease in esterified cholesterol. Diacylglycerides and free fatty acids tend to increase. Phosphatidylcholine and phosphatidylethanolamine decrease, whereas phosphatidylserine, sphingomyelin, and phosphatidylinositol increase. The main fatty acids of the retina also undergo changes. At E7, myriotic acid increases, and oleic acid and polyunsaturated fatty acids such as arachidonic acid and docosahexaenoic acid decrease. From E18 onward, there is some recovery, except for fatty acids, which recover earlier. From a morphological point of view, alcohol effects on retinal development are various: increase of intercellular spaces in all cell layers, pyknosis with loss of cellularity in the inner nuclear cell layer and ganglion cell layer, retarded or disorderly cell migration, early cell differentiation, and loss of immunoreactivity for myelin oligodendrocyte-specific protein.

CONCLUSIONS

Acute alcohol exposure during embryo development causes the lipid composition of the retina to change, with a trend to recovery in the last stages. These alterations are in line with the changes observed at a morphological level.

Omega-3 fatty acid deficiencies in neurodevelopment, aggression and autonomic dysregulation: opportunities for intervention

Mechanisms by which aggressive and depressive disorders may be exacerbated by nutritional deficiencies in omega-3 fatty acids are considered. Early developmental deficiencies in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) may lower serotonin levels at critical periods of neurodevelopment and may result in a cascade of suboptimal development of neurotransmitter systems limiting regulation of the limbic system by the frontal cortex. Residual developmental deficits may be manifest as dysregulation of sympathetic responses to stress including decreased heart rate variability and hypertension, which in turn have been linked to behavioral dysregulation. Little direct data are available to disentangle residual neurodevelopmental effects from reversible adult pathologies. Ensuring optimal intakes of omega-3 fatty acids during early development and adulthood shows considerable promise in preventing aggression and hostility.

A role for direct interactions in the modulation of rhodopsin by omega-3 polyunsaturated lipids

Rhodopsin, the G protein-coupled receptor primarily responsible for sensing light, is found in an environment rich in polyunsaturated lipid chains and cholesterol. Biophysical experiments have shown that lipid unsaturation and cholesterol both have significant effects on rhodopsin's stability and function; omega-3 polyunsaturated chains, such as docosahexaenoic acid (DHA), destabilize rhodopsin and enhance the kinetics of the photocycle, whereas cholesterol has the opposite effect. Here, we use molecular dynamics simulations to investigate the possibility that polyunsaturated chains modulate rhodopsin stability and kinetics via specific direct interactions. By analyzing the results of 26 independent 100-ns simulations of dark-adapted rhodopsin, we found that DHA routinely forms tight associations with the protein in a small number of specific locations qualitatively different from the nonspecific interactions made by saturated chains and cholesterol. Furthermore, the presence of tightly packed DHA molecules tends to weaken the interhelical packing. These results are consistent with recent NMR work, which proposes that rhodopsin binds DHA, and they suggest a molecular rationale for DHA's effects on rhodopsin stability and kinetics.

Evidence for a mechanism by which omega-3 polyunsaturated lipids may affect membrane protein function

We have calculated the lateral pressure profile from well-converged, experimentally validated, molecular dynamics simulations of hydrated lipid bilayer membranes containing highly polyunsaturated fatty acids. The three simulations, each 30 ns in length, contain omega-3 fatty acids, omega-6 fatty acids, and a mixture of omega-3 fatty acids and cholesterol and were continued from previously published simulations that demonstrated excellent agreement with a wide variety of experimental measurements. We find that the distribution of lateral stress within the hydrophobic core of the membrane is sensitively dependent on the degree of chain unsaturation and on the presence of cholesterol. Replacing omega-3 fatty acids with omega-6 chains, or incorporating cholesterol into the membrane, shifts the repulsive lateral chain pressure away from the lipid/water interface toward the bilayer interior. This may support a previously proposed mechanism by which lipid composition may affect conformational equilibrium for integral membrane proteins.

Mass spectrometric studies on brain metabolism, using stable isotopes

In fields related to biomedicine, mass spectrometry has been applied to metabolism research and chemical structural analysis. The introduction of stable isotopes has advanced research related to in vivo metabolism. Stable-isotope labeling combined with mass spectrometry appears to be a superior method for the metabolism studies, because it compensates for the shortcomings of conventional techniques that use radioisotopes. Biomolecules labeled with stable isotopes have provided solid evidence of their metabolic pathways. Labeled large molecules, however, cannot homogeneously mix in vivo with the corresponding endogenous pools. To overcome that problem, small tracers labeled with stable isotopes have been applied to in vivo studies because they can diffuse and attain a homogeneous distribution throughout the inter- and intracellular spaces. In particular, D(2)O-labeling methods have been used for studies of the metabolism in different organs, including the brain, which is isolated from other extraneural organs by the blood-brain barrier (BBB). Cellular components, such as lipids, carbohydrates, proteins, and DNA, can be endogenously and concurrently labeled with deuterium, and their metabolic fluxes examined by mass spectrometry. Application of the D(2)O-labeling method to the measurements of lipid metabolism and membrane turnover in the brain is described, and the potential advantages of this method are discussed in this review. This methodology also appears to have the potential to be applied to dynamic and functional metabolomics.

Alcohol consumption in pregnant, black women is associated with decreased plasma and erythrocyte docosahexaenoic acid

BACKGROUND

Inner-city, black women are among those groups that are at higher risk for having infants with fetal alcohol spectrum disorders that can include life-long neurobehavioral and cognitive impairments. Chronic alcohol consumption can decrease amounts of docosahexaenoic acid (DHA), a fatty acid that is essential for optimal infant neural and retinal development in a variety of tissues.

METHODS

Black women who presented at an inner-city antenatal clinic for their first prenatal visit were recruited into a longitudinal, observational study. Alcohol intake was determined by a structured interview. Participants provided blood specimens and completed food frequency surveys at 24 weeks of gestation, infant delivery, and 3 months postpartum. Fatty acid composition analyses were completed on 307, 260, and 243 for plasma and 278, 261, and 242 erythrocyte specimens at 24 weeks of gestation, delivery, and 3 months postpartum, respectively.

RESULTS

Proportion of drinking days at the first prenatal visit was associated with decreased DHA in plasma and erythrocytes throughout the study. This association was the strongest at 24 weeks of gestation. In addition, an interaction between proportion of drinking days at the time of conception and ounces of absolute alcohol per drinking day at the time of conception was detected and demonstrated that, in daily drinkers, high intakes of alcohol are associated with decreased DHA and arachidonic acid (AA) concentrations in plasma.

CONCLUSIONS

Frequent and high intakes of alcohol that have been previously associated with fetal alcohol spectrum disorders are also associated with decreased maternal DHA and AA plasma concentrations. The present findings indicate that maternal DHA deficiency is associated with high-risk drinking and may contribute to the mechanism(s) of alcohol-related neurodevelopmental disorders.

Effects of alcohol intake during pregnancy on docosahexaenoic acid and arachidonic acid in umbilical cord vessels of black women

OBJECTIVE

Alcohol influences the intake and metabolism of several nutrients including long-chain polyunsaturated fatty acids (LC-PUFAs). The LC-PUFAs docosahexaenoic acid (DHA) and arachidonic acid (AA) are particularly crucial for intrauterine growth and brain development. We hypothesized that alcohol consumption adversely affects LC-PUFA levels in pregnant women and their newborn infants.

METHODS

Pregnant black women (N = 208) presenting at a core city antenatal clinic were screened and recruited. Shortly before delivery, maternal plasma was collected. After delivery, umbilical arteries and veins were dissected from the cords, total lipids were extracted from the vessel tissues and maternal plasma, and fatty acid levels were assayed by gas chromatography. For statistical analysis, subjects were categorized according to absolute alcohol intake per day (AAD) and absolute alcohol intake per drinking day (AADD) around the time of conception, with smoking and other potential confounders included in the analyses.

RESULTS

Significant differences in fatty acid composition of total lipid extracts were detected in umbilical cord vessels among the AADD groups: abstainers (AADD = 0), moderate drinkers (AADD < 130 g), and heavy drinkers (AADD > or = 130 g). DHA and AA content in the arterial umbilical vessel wall was approximately 14% and approximately 10% higher in the moderate (n = 127) and heavy (n = 32) alcohol groups, respectively, than in abstainers (n = 49). A small, nonsignificant increase ( approximately 3%) was seen in the umbilical vein for AA but not for DHA. Alcohol intake was positively correlated to both DHA and AA concentrations in the arterial vessel wall but to neither in the venous wall nor maternal plasma. Maternal plasma DHA was positively correlated with both umbilical arteries and vein DHA, but there were no significant correlations for AA between maternal plasma and either umbilical vessel.

CONCLUSIONS

Our findings indicate that alcohol intake during pregnancy is associated with altered DHA and AA status in fetal tissues. Although differences may be due to either metabolism and/or distribution, it is most likely a result of a direct influence of alcohol on fetal metabolism.

Polyunsaturated fatty acid levels in red cell membranes of unmedicated schizophrenic patients

There are several reports of reduced levels of polyunsaturated fatty acids (PUFA), particularly arachidonic acid (AA) and docosahexaenoic acid (DHA), in membrane phospholipid from various tissues including red blood cells (RBC) taken from schizophrenic patients. However, reports have not been entirely consistent and most studies have been confounded by the potential effects of environmental factors including antipsychotic medication and diet. We measured PUFA levels in RBC from two separate groups of unmedicated patients and control subjects from India and Malaysia, populations which have substantial differences in diet. We found no significant difference in levels of AA between patients and control subjects in either population. Levels of adrenic acid were significantly reduced, and levels of DHA significantly increased in both clinical populations. However, diet-related differences in DHA between the populations from India and Malaysia were much greater than differences between schizophrenic patients and controls. It is concluded that reduced RBC membrane levels of AA and DHA are not pathognomic of schizophrenia but that variations in cell membrane fatty acid levels are an epiphenomenon which may reflect underlying abnormalities of phospholipid and fatty acid metabolism and their interaction with environmental factors including medication and diet.

Development of Alcoholic Fatty Liver and Fibrosis in Rhesus Monkeys Fed a Low n-3 Fatty Acid Diet

BACKGROUND

The amount and type of dietary fat seem to be important factors that modulate the development of alcohol-induced liver steatosis and fibrosis. Various alcohol-feeding studies in animals have been used to model some of the symptoms that occur in liver disease in humans.

METHODS

Rhesus monkeys (Macaca mulatta) were maintained on a diet that had a very low concentration of alpha-linolenic acid and were given free access to an artificially sweetened 7% ethanol solution. Control and ethanol-consuming animals were maintained on a diet in which the linoleate content was adequate (1.4% of energy); however, alpha-linoleate represented only 0.08% of energy. Liver specimens were obtained, and the fatty acid composition of the liver phospholipids, cholesterol esters, and triglycerides of the two groups were compared at 5 years and histopathology of tissue samples were compared at 3 and 5 years.

RESULTS

The mean consumption of ethanol for this group over a 5-year period was 2.4 g.kg.day. As a consequence of the ethanol-dietary treatment, there were significantly lower concentrations of several polyunsaturated fatty acids in the liver phospholipids of the alcohol-treated group, including arachidonic acid and most of the n-3 fatty acids and particularly docosahexaenoic acid, when compared with dietary controls. Liver specimens from animals in the ethanol group at 5 years showed a marked degree of steatosis, both focal and diffuse cellular necrosis, and an increase in the development of fibrosis compared with specimens obtained at 3 years and with those from dietary controls, in which there was no evidence of fibrotic lesions.

CONCLUSION

These findings suggest that the advancement of ethanol-induced liver disease in rhesus monkeys may be modulated by the amount and type of dietary essential fatty acids and that a marginal intake of n-3 fatty acids may be a permissive factor in the development of liver disease in primates.

Perspectives on alcohol consumption: liver polyunsaturated fatty acids and essential fatty acid metabolism

In this article, subjects diagnosed with alcoholic liver disease are shown to have lower concentrations of several polyunsaturated fatty acids (PUFAs), including 18:2n6, 18:3n6, 20:3n6, 18:3n3, 22:5n3, and 22:6n3, but not 20:4n6 and 22:4n6, nor 22:5n6, in the total lipid extracts of their livers compared with findings for specimens obtained from patients diagnosed with primary biliary cirrhosis and from control subjects. Findings of studies in animals have demonstrated that prolonged alcohol consumption reduces liver polyunsaturate content. However, the effect of ethanol on the elongation/desaturation of essential fatty acids is complex, as in vitro study results indicate that the direction of the effect of alcohol may be related to the dose of alcohol. Findings of studies in hepatocyte cell culture indicate that ethanol increased delta-5 and delta-6 desaturase activities throughout a broad concentration range. In contrast, lower liver desaturase activity has been reported in animals consuming high concentrations of alcohol (36%-40% energy) over a period of several months. Findings from in vivo isotope tracers studies in nonhuman primates and felines indicate that prolonged periods of moderate (mean consumption 2.6 g kg(-1) d(-1) and 1.2 g kg(-1) d(-1), respectively) alcohol consumption had no effect on the uptake of either linoleic (18:2n6) or alpha-linolenic (18:3n3) acids into the plasma and lead to an increased incorporation of these deuterated precursors into 20:4n6 and 22:6n3. Thus, this likely reflects a stimulated, rather than an inhibited, production of long-chain PUFAs. In numerous studies in various species, investigators have documented that alcohol consumption can increase the level of lipid peroxidation in tissues, and sustained periods of ethanol-induced peroxidation can deplete tissues of PUFAs. A hypothesis to rationalize the long-term effects of alcohol consumption on liver PUFA concentration that takes into consideration the effect of ethanol on essential fatty acid metabolism is presented.

Alterations in hippocampal phospholipid profile by prenatal exposure to ethanol

It has been suggested that hippocampus-related cognitive processes are especially sensitive to ethanol. To provide an insight into the biochemical mechanisms underlying the hippocampus-related functional deficits associated with prenatal ethanol exposure, we investigated the effects of chronic ethanol exposure on the phospholipid profile in developing rat hippocampi. High-performance liquid chromatography/electrospray ionization-mass spectrometry analysis revealed that ethanol lowered the levels of total phosphatidylserine (PS) by 15-20% at all ages examined, primarily owing to the reduction in 1-stearoyl-2-docosahexaenoyl-PS (18:0,22:6n-3-PS) species. Ethanol exposure also led to a decrease in phosphatidylcholine (PC) and an increase in phosphatidylethanolamine (PE), but the total phospholipid content was not significantly changed. At the fatty acid level, ethanol exposure significantly decreased the 22:6n-3 content at postnatal days 0 and 21, with a slight increase in 22:5n-6, without changing the total fatty acid content significantly. In conclusion, ethanol depleted PS, especially 22:6-containing species, and PC from hippocampal membranes with concomitant increase in PE. Alteration of the phospholipid profile in the hippocampus resulting from exposure to ethanol during prenatal and developmental stages may have significant implications with respect to the cognitive dysfunction observed in fetal alcohol syndrome.

Substrate preference in phosphatidylserine biosynthesis for docosahexaenoic acid containing species

Neuronal membranes contain high levels of phosphatidylserine (PS) and docosahexaenoic acid (22:6n-3, DHA). In this study, substrate preference in PS synthesis was determined to gain insight on the biochemical basis for concentrating PS in neuronal membranes where 22:6n-3 is highly enriched. We first established an in vitro assay method using unilamellar vesicles (LUV) of deuterium-labeled substrates and reversed-phase HPLC/electrospray ionization (ESI) mass spectrometry. The PS production by the incubation of deuterium-labeled substrate and microsomal fractions was monitored. We found that tissue-specific substrate preference exists in PS synthesis. Microsomes from the cerebral cortex synthesized PS from 18:0,22:6-PC most favorably among the PC substrates tested, followed by 18:0,22:5-PC, resulting in the PC substrate preference in the order of 18:0,22:6 > 18:0,22:5 > 18:0,20:4 = 18:0,18:1. Liver microsomes also preferred 18:0,22:6-PC as the substrate in PS synthesis but did not use 18:0,22:5-PC favorably. The 18:0,22:5-PC species was converted to PS at the similar extent as 18:0,20:4- or 18:0,18:1-PC species in the liver. Both brain and liver microsomes showed a preference for 18:0 over 16:0 as the sn-1 fatty acid. From these data it was deduced that preferential conversion of 18:0,22:6-PC to the corresponding PS species is at least partly responsible for concentrating PS in neuronal tissues where 22:6n-3 is particularly abundant. The distinctive preference for 18:0,22:5-PS observed with brain microsomes may help to maintain PS at a high level in the brain when 22:6n-3 is replaced by 22:5n-3 as in the case of n-3 fatty acid deficiency.

Docosahexaenoic acid: membrane properties of a unique fatty acid

Docosahexaenoic acid (DHA) with 22-carbons and 6 double bonds is the extreme example of an omega-3 polyunsaturated fatty acid (PUFA). DHA has strong medical implications since its dietary presence has been positively linked to the prevention of numerous human afflictions including cancer and heart disease. The PUFA, moreover, is essential to neurological function. It is remarkable that one simple molecule has been reported to affect so many seemingly unrelated biological processes. Although details of a molecular mode of action remain elusive, DHA must be acting at a fundamental level common to many tissues that is related to the high degree of conformational flexibility that the multiple double bonds have been identified to confer. One likely target for DHA action is at the cell membrane where the fatty acid is known to readily incorporate into membrane phospholipids. Once esterified into phospholipids DHA has been demonstrated to significantly alter many basic properties of membranes including acyl chain order and "fluidity", phase behavior, elastic compressibility, permeability, fusion, flip-flop and protein activity. It is concluded that DHA's interaction with other membrane lipids, particularly cholesterol, may play a prominent role in modulating the local structure and function of cell membranes.

Embryonic exposure to exogenous alpha- and gamma-tocopherol partially attenuates ethanol-induced changes in brain morphology and brain membrane fatty acid composition

Previous studies demonstrated that embryonic exposure to ethanol (EtOH) promoted a reduction in brain mass, a reduction in brain neuron densities, and a reduction in membrane long-chain polyunsaturated fatty acids (PUFAs) in embryonic chick brains. These EtOH-induced reductions in brain membrane PUFAs may be the result of lipid peroxidation because embryonic exposure to exogenous alpha- or gamma-tocopherol partially attenuated EtOH-induced reductions in membrane PUFAs. In this paper, we report that embryonic exposure to exogenous alpha- or gamma-tocopherol attenuated EtOH-induced decreases in endogenous levels of alpha-tocopherol in both embryonic chick brains and liver. Embryonic exposure to exogenous alpha- or gamma-tocopherol also partially attenuated EtOH-induced reductions in brain neuron densities within the cerebral hemispheres of embryonic chick brains. Finally, embryonic exposure to exogenous alpha- or gamma-tocopherol also partially attenuated EtOH-induced reductions in long-chain PUFAs in 2-day old neonatal chick brains.

Effects of red wine consumption on kidney FA composition

We studied the effects of red wine consumption on the FA composition of rat kidney. Four groups of adult male rats were fed a balanced diet for 10 wk. The drinking fluid was water (control), red wine, alcohol-free red wine, or ethanol (12.5%, vol/vol). FA composition, lipid peroxidation, and cytochrome P450 content were determined in the kidney. The antioxidant capacity of plasma was also measured. Ethanol decreased the content of long-chain PUFA, whereas red wine maintained the levels of arachidonic (20:4n-6) and eicosapentaenoic (20:5n-3) acids and alcohol-free red wine significantly increased the levels of 20:4n-6. Lipid peroxidation in the red wine and alcohol-free red wine groups was significantly lower than that of both the control and ethanol groups. The diminished renal lipid peroxidation was associated with an increased antioxidant capacity of plasma. Renal cytochrome P450 was elevated by 50% in the ethanol group and diminished by 20% in the alcohol-free red wine group. These data suggest that moderate red wine consumption could contribute to the preservation of the contents of n-3 and n-6 PUFA, particularly 20:4n-6, in rat kidney. Although ethanol increased the content of cytochrome P450 in the kidney, this effect was eliminated by the nonalcoholic components of red wine.

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.

A study of the behavioral effects of prenatal ethanol exposure in mice fed a diet marginally deficient in essential fatty acids for two generations

This study investigated the effects of prenatal ethanol exposure on measures of fecundity, growth, behavioral development and learning in mice that had been fed a diet, marginal in essential fatty acid (EFA) content for two generations. The first generation of mice were fed one of two diets (adequate or marginal EFA) from conception. They were mated at 10 weeks, and from days 5 to 17 of gestation dams on each diet were fed equivalent daily amounts of a liquid diet containing either 22.5% of the calories as ethanol or with maltose-dextrin substituted isocalorically for ethanol. An additional control group was fed lab chow ad libitum. Offspring were maintained on their respective diets after weaning. The marginal-EFA diet led to a large increase in perinatal mortality; it also decreased body and brain weight in the surviving pups, and retarded behavioural development. Ethanol retarded behavioral development in females, and delayed the acquisition of learning the position of an escape platform in a T water-maze in the mice fed the adequate-EFA diet. The effects of ethanol did not appear to be worse in the mice fed the marginal-EFA diet, but these data must be considered in light of the high mortality on this diet, where only the healthiest pups may have survived.

Formation of inverted hexagonal phase in SDPE as observed by solid-state (31)P NMR

Docosahexaenoic acid (DHA), the longest and most unsaturated fatty acid commonly found in biological membranes, is known to affect various membrane properties. In a variety of cell membranes, DHA is primarily incorporated in phosphatidylethanolamines, where its function remains poorly understood. In order to understand the role of DHA in influencing membrane structure, we utilize (31)P NMR spectroscopy to study the phase behavior of 1-stearoyl-2-docosahexaenoyl-sn-glycerophosphoethanolamine (SDPE) in comparison to 1-palmitoyl-2-oleoyl-sn-glycerophosphoethanolamine (POPE) from 20 to 50 degrees C. Spectra of SDPE phospholipids show the formation of inverted hexagonal phase (H(II)) from 20 to 50 degrees C; in contrast, POPE mutilamellar dispersions exist in a lamellar liquid-crystalline phase (L(alpha)) at the same temperatures. The ability of SDPE to adopt nonbilayer phases at a physiological temperature may indicate its role in imparting negative curvature stress upon the membrane and may affect local molecular organization including the formation of lipid microdomains within biological membranes.

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.

Effects of gestational alcohol exposure on the fatty acid composition of umbilical cord serum in humans

This study examined the effects of maternal periconceptional alcohol intake on polyunsaturated fatty acid (PUFA) concentrations in human neonates. The area percentage of each fatty acid in cord blood serum from 12 infants born to control women (who consumed <2 mL absolute ethanol/d) was compared with that of 9 infants born to women whose periconceptional alcohol intake averaged > or = 30mL absolute ethanol/d. Periconceptional alcohol use was associated with a 30% increase in the proportion of docosahexaenoic acid (22:6n-3) in cord blood (3.0% of total lipid in control infants compared with 3.9% in alcohol-exposed infants; P < 0.01). The rise in the proportion of 22:6n-3 was responsible for increases in the ratio of n-3 to n-6 fatty acids and the ratio of long-chain n-3 to n-6 fatty acids (P < 0.055). Examination of the lipid-class fatty acid profile indicated that serum lipid alterations were localized to the cholesterol esters; 22:6n-3 in the cholesterol esters of alcohol-exposed infants increased 54% (P < 0.011) and arachidonic acid increased 55% (P < 0. 005). The relative fatty acyl composition of maternal serum showed a significant increase in 18:0 fatty acids in the alcohol-exposed group (25%, P < 0.005) but there were no changes in the other fatty acids. The increase in the proportion of 22:6n-3 was unexpected but is consistent with the hypothesis that this essential lipid may be conserved selectively. These results imply that the lifelong neurobehavioral and sensory dysfunction in fetal alcohol syndrome and other alcohol-related neurodevelopmental disorders may be due in part to PUFA dysregulation.

Plasma total cholesterol concentrations do not predict cerebrospinal fluid neurotransmitter metabolites: implications for the biophysical role of highly unsaturated fatty acids

Low concentrations of a metabolite of serotonin found in cerebrospinal fluid (CSF), 5-hydroxyindolacetic acid (5-HIAA), are strongly associated with suicidal and violent behaviors. Although lowering of plasma total cholesterol has been suggested to increase mortality from suicide and violence by decreasing concentrations of CSF 5-HIAA via changes in membrane biophysical properties, highly unsaturated fatty acids may play a more important role. Violent and nonviolent comparison groups, early- and late-onset alcoholics, and healthy comparison subjects were studied to control for alcohol use and predisposition to violence. Fasting plasma total cholesterol and CSF were assayed under stringently controlled conditions. When all groups were combined (n = 234), plasma cholesterol concentrations had a weak positive correlation with CSF 5-HIAA (r = 0.18, P < 0.01). However, age correlated with both plasma total cholesterol and CSF 5-HIAA concentrations. When age was included in multiple regression models, the correlation between cholesterol and CSF 5-HIAA concentrations was not significant. Cholesterol correlated weakly with CSF 5-HIAA concentrations only in late-onset alcoholics after age was controlled for, but the relation was not significant after correction for multiple testing. CSF homovanillic acid did not correlate with plasma total cholesterol in any group. Plasma total cholesterol had no apparent relation to CSF neurotransmitter metabolites in any group of subjects. Highly unsaturated essential fatty acids, which are also critical determinants of membrane biophysical properties and may be linked to brain serotonin concentrations, should also be considered in studies examining the effect of lowering fat intake on the incidence of suicide and violence.

The influence of membrane lateral pressures on simple geometric models of protein conformational equilibria

The function of many intrinsic membrane proteins requires a conformational transition that is often strongly influenced by the molecular composition of the bilayer in which the protein is embedded. Recently, a mechanism for this shift in conformational equilibrium was suggested, in which it is argued that a shift in distribution of lateral pressures of the bilayer resulting from a change in lipid composition alters the amount of mechanical work of the protein conformational transition, if the change in the cross-sectional area profile of the protein varies with depth within the bilayer. As there is little information on the change in shape of the transmembrane region of any protein, various simple geometric models are considered. For both a generic model, and more specific models that approximate likely cooperative rearrangements of alpha-helices in bundles, it is found that the conformational equilibrium depends on the first and second integral moments of the lateral pressure distribution. In addition to revealing the possible physical underpinnings of the well-known correlation between protein activity and the 'nonlamellar' tendency of bilayer lipids, this dependence on moments of the pressure profile allows for prediction of the relative effects of different lipid compositional changes even in the absence of information on specific protein shape changes. Effects of variation in acyl chain length, degree and position of cis-unsaturation, and addition of cholesterol and small interfacially-active solutes (n-alkanols) are compared.

Assessment of long-chain polyunsaturated fatty acid nutritional supplementation on infant neurobehavioral development and visual acuity

The aims of this paper are (i) to consider how best to examine effects of long-chain polyunsaturated fatty acid nutritional supplementation or deficiency on infant neurobehavioral development, after controlling for other factors that might influence outcome, including maternal demographic, intellectual, and personality characteristics, and (ii) to present new findings on the relation between visual acuity and processing speed and the effects of prenatal alcohol exposure and visual acuity on infant information processing. The following topics are also addressed: (i) breastfeeding and intelligence, (ii) criteria for the selection and control of potential confounding variables, and (iii) new infant information processing measures.

A replication study of violent and nonviolent subjects: cerebrospinal fluid metabolites of serotonin and dopamine are predicted by plasma essential fatty acids

BACKGROUND

Among an independent group of subjects selected for their history of violent, impulsive behaviors and nonviolent control subjects, we attempted to replicate the finding that plasma docosahexaenoic acid concentrations were negatively correlated with cerebrospinal fluid 5-hydroxyindoleacetic acid (CSF 5-HIAA) concentrations.

METHODS

CSF 5-HIAA and homovanillic acid (HVA), fasting total cholesterol, and plasma fatty acid concentrations were examined in violent and nonviolent subjects matched for their severity of alcohol dependence.

RESULTS

Violent subjects had significantly higher lifetime violence and hostility ratings and lower concentrations of CSF 5-HIAA than nonviolent subjects. Plasma docosahexaenoic acid was negatively correlated with CSF 5-HIAA only among violent subjects.

CONCLUSIONS

This observational study suggests that dietary essential fatty acids may change neurotransmitter concentrations. Prospective dietary intervention trials will be required to determine if increasing dietary intake of docosahexaenoic acid will increase or decrease either CSF 5-HIAA concentrations or impulsive and violent behaviors.