Effects of chronic alcohol consumption on enzyme activities and active methionine absorption in the small intestine of pregnant rats

Association of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer: the Japan Public Health Center-based (JPHC) prospective study

Background

B vitamins and methionine are essential substrates in the one-carbon metabolism pathway involved in DNA synthesis and methylation. They may have essential roles in cancer development. We aimed to evaluate the associations of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer (EC) using data from the Japan Public Health Center-based Prospective Study.

Methods

We included 87,053 Japanese individuals who completed a food frequency questionnaire and were followed up from 1995–1998 to 2013 and 2015. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated by Cox proportional-hazard regression across quintiles of dietary intakes of B vitamins and methionine.

Results

After 1,456,678 person-years of follow-up, 427 EC cases were documented. The multivariable HR (95% CI) of incident EC in the highest versus lowest quintile of dietary intake of vitamin B12 was 1.75 (1.13–2.71; p-trend=0.01). Stratification analysis based on alcohol consumption showed that higher dietary intakes of vitamin B12 and methionine were associated with an increased risk of EC among never-drinkers; HRs (95% CIs) were 2.82 (1.18–6.74; p-trend=0.009; p-interaction=0.18) and 3.45 (1.32–9.06; p-trend=0.003; p-interaction 0.02) for vitamin B12 and methionine, respectively. Meanwhile, there was no association between vitamin B12 and methionine intake with the risk of EC among drinkers. There were no associations between dietary intake of folate or vitamin B6 and the risk of EC.

Conclusion

Dietary intake of vitamin B12 was positively associated with the risk of EC in the Japanese population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08721-8.

Effects of antioxidant supplementation on duodenal Se-Met absorption in ethanol-exposed rat offspring in vivo

The nutritional deficiencies provoked by ethanol consumption, during gestation or lactation, can contribute to multiple birth defects in offspring. In order to improve our knowledge about selenium (Se) distribution in pups exposed to ethanol, the present study evaluated the effect of this drug on intestinal development and determined its action on duodenal absorption of selenomethionine (Se-Met). To determinate if supplementation could improve Se absorption and its serum values, we used two antioxidant supplemented regimens on dams, with selenium alone or selenium plus folic acid, and obtained six groups of pups: C (control), A (alcohol), CS (control + Se), AS (alcohol + Se), CFS (control + Se + folic acid) and AFS (alcohol + Se + folic acid). Duodenal Se-Met transport was performed using an in vivo perfusion method. Se levels were measured by graphite furnace atomic absorption spectrometry. The supplemented diets utilized had a positive influence on body growth, duodenal perimeter and Se content in ethanol-exposed pups. Ethanol exposure increased Se-Met duodenal absorption in all pups, supplemented or not, presenting the highest values of maximal velocity (V(max)) compared with their control counterparts. The affinity constant (K(m)) increased according to rank: A>AS>AFS groups. These results suggest that although antioxidant supplementation does not restore Se-Met absorption to normal values, it enhances the affinity of the transporters for the substrate and improves the damage caused by ethanol in the duodenal mucosa.

Prenatal choline supplementation mitigates the adverse effects of prenatal alcohol exposure on development in rats

Prenatal alcohol exposure can lead to a range of physical, neurological, and behavioral alterations referred to as fetal alcohol spectrum disorders (FASD). Variability in outcome observed among children with FASD is likely related to various pre- and postnatal factors, including nutritional variables. Choline is an essential nutrient that influences brain and behavioral development. Recent animal research indicates that prenatal choline supplementation leads to long-lasting cognitive enhancement, as well as changes in brain morphology, electrophysiology and neurochemistry. The present study examined whether choline supplementation during ethanol exposure effectively reduces fetal alcohol effects. Pregnant dams were exposed to 6.0g/kg/day ethanol via intubation from gestational days (GD) 5-20; pair-fed and lab chow controls were included. During treatment, subjects from each group received choline chloride (250mg/kg/day) or vehicle. Physical development and behavioral development (righting reflex, geotactic reflex, cliff avoidance, reflex suspension and hindlimb coordination) were examined. Subjects prenatally exposed to alcohol exhibited reduced birth weight and brain weight, delays in eye opening and incisor emergence, and alterations in the development of all behaviors. Choline supplementation significantly attenuated ethanol's effects on birth and brain weight, incisor emergence, and most behavioral measures. In fact, behavioral performance of ethanol-exposed subjects treated with choline did not differ from that of controls. Importantly, choline supplementation did not influence peak blood alcohol level or metabolism, indicating that choline's effects were not due to differential alcohol exposure. These data indicate early dietary supplements may reduce the severity of some fetal alcohol effects, findings with important implications for children of women who drink alcohol during pregnancy.

Mitochondrial S-adenosyl-L-methionine transport is insensitive to alcohol-mediated changes in membrane dynamics

BACKGROUND

Alcohol-induced liver injury is associated with decreased S-adenosyl-l-methionine (SAM)/S-adenosyl-l-homocysteine (SAH) ratio and mitochondrial glutathione (mGSH) depletion, which has been shown to sensitize hepatocytes to tumor necrosis factor (TNF).

AIMS

As the effect of alcohol on mitochondrial SAM (mSAM) has been poorly characterized, our aim was to examine the status and transport of mSAM in relation to that of mGSH during alcohol intake.

METHODS

Sprague-Dawley rats were pair fed Lieber-DeCarli diets containing alcohol for 1 to 4 weeks and liver fractionated into cytosol and mitochondria to examine the mSAM transport and its sensitivity to membrane dynamics.

RESULTS

We found that cytosol SAM was depleted from the first week of alcohol feeding, with mSAM levels paralleling these changes. Cytosol SAH, however, increased during the first 3 weeks of alcohol intake, whereas its mitochondrial levels remained unchanged. mGSH depletion occurred by 3 to 4 weeks of alcohol intake due to cholesterol-mediated impaired transport from the cytosol. In contrast to this outcome, the transport of SAM into hepatic mitochondria was unaffected by alcohol intake and resistant to cholesterol-mediated perturbations in membrane dynamics; furthermore cytosolic SAH accumulation in primary hepatocytes by SAH hydrolase inhibition reproduced the mSAM depletion by alcohol due to the competition of SAH with SAM for mitochondrial transport. However, alcohol feeding did not potentiate the sensitivity to inhibition by SAH accumulation.

CONCLUSIONS

Alcohol-induced mSAM depletion precedes that of mGSH and occurs independently of alcohol-mediated perturbations in membrane dynamics, disproving an inherent defect in the mSAM transport by alcohol. These findings suggest that the early mSAM depletion may contribute to the alterations of mitochondrial membrane dynamics and the subsequent mGSH down-regulation induced by alcohol feeding.

Syndromes, disorders and maternal risk factors associated with neural tube defects (VI)

Neural tube defects (NTDs) may be associated with syndromes, disorders, and maternal and fetal risk factors. This article provides a comprehensive review of the syndromes, disorders, and maternal and fetal risk factors associated with NTDs, including maternal fumonisin consumption, periconceptional zinc deficiency, parental occupational exposure and residential proximity to pesticides, lower socioeconomic status, fetal alcohol syndrome, mutations in the VANGL1 gene, human athymic Nude/SCID fetus, and single nucleotide polymorphism in the NOS3 gene. NTDs associated with these syndromes, disorders, and maternal and fetal risk factors are a rare but important cause of NTDs. The recurrence risk and the preventive effect of maternal folic acid intake in NTDs associated with syndromes, disorders and maternal risk factors may be different from those of nonsyndromic multifactorial NTDs. Perinatal diagnosis of NTDs should alert doctors to the syndromes, disorders, and maternal and fetal risk factors associated with NTDs, and prompt thorough etiologic investigation and genetic counseling.

Chronic binge ethanol-mediated acidemia reduces availability of glutamine and related amino acids in maternal plasma of pregnant sheep

Heavy drinking during pregnancy can result in fetal alcohol syndrome (FAS), of which, fetal and postnatal growth retardation and central nervous system deficits are cardinal features. Although a number of mechanisms have been proposed, none fully account for these deficiencies. We have previously reported that maternal ethanol exposure (1.75 g/kg) results in transient acidemia in the mother and fetus. Alterations in pH are known to regulate glutamine homeostasis. Therefore, we hypothesized that chronic binge ethanol-mediated acidosis reduces glutamine concentrations in maternal plasma that result in decreases in the circulating levels of amino acids related to glutamine metabolism. Pregnant ewes were divided into three groups: ethanol (1.75 g/kg), saline control, and acidemia (inspired fractional carbon dioxide [CO(2)] was manipulated to mimic the maternal arterial pH pattern created by ethanol). The experiment was conducted on three consecutive days followed by four days without treatment beginning on gestational day (GD) 109, continuing to GD 132. Plasma samples were analyzed for nutrients and metabolites using HPLC and spectrophotometric methods. Maternal plasma concentrations of glutamate increased (58%), whereas glutamine, citrulline, and arginine decreased (between 14 and 53%) in response to an acute challenge after the chronic exposure in ethanol-treated ewes. No differences in these amino acid concentrations were noted between the ethanol and acidemic group subjects. Maternal plasma lactate levels increased by approximately 100% in response to ethanol, whereas glucose and urea levels did not change in any group. We conclude that maternal chronic binge ethanol consumption results in acidosis-mediated reductions in circulating levels of glutamine and related amino acids that could be responsible for neuronal deficits, altered fetal growth, development, and programming. We also speculate that the consequent increase in fetal glutamate during critical periods of brain development may contribute to the pathogenesis of FAS.

Antioxidative Treatment Diminishes Ethanol-Induced Congenital Malformations in the Rat

BACKGROUND

Intrauterine exposure to ethanol causes embryonic and fetal growth retardation and maldevelopment. Oxidative stress in mother and offspring has been suggested to be part of the teratogenic mechanism, and supplementation of antioxidative agents to the pregnant women may therefore be of value in future prophylactic treatment regimen. There is a need for in vivo experimental work in this field, and in the present study, our aim was to investigate whether chronic ethanol consumption induced congenital malformations in rats and, if so, whether dietary supplementation of vitamin E (alpha-tocopherol) diminished such maldevelopment.

METHODS

Female Sprague-Dawley rats were given drinking water containing 20% ethanol and half of these received food containing 5% vitamin E. Non-ethanol-exposed female rats, with or without vitamin E treatment, served as controls. The pregnancy was interrupted on gestational day 20 when the offspring was evaluated morphologically and fetal hepatic 8-iso-PGF(2alpha) levels were measured to assess the degree of fetal oxidative stress.

RESULTS

Exposure to 20% ethanol increased maternal blood ethanol to 1.5 promille and increased resorption and malformation rates in the offspring. Maternal vitamin E treatment did not affect blood ethanol levels, but normalized fetal development. The fetal hepatic levels of 8-iso-PGF(2alpha) were increased in the ethanol-exposed group and normalized by vitamin E treatment of the mother.

CONCLUSIONS

Ethanol exposure disturbs embryogenesis partly by enhanced oxidative stress, and the adverse effects can be ameliorated by antioxidative treatment.

Ethanol-Induced Fetal Dysmorphogenesis in the Mouse Is Diminished by High Antioxidative Capacity of the Mother

Intrauterine exposure to ethanol causes embryonic and fetal maldevelopment. Oxidative stress in mother and offspring has been suggested to be part of the teratogenic mechanism of ethanol. Here we aimed to assess the importance of maternal and fetal antioxidative capability for the risk of dysmorphogenesis in the offspring. We used male and female mice with different levels of superoxide dismutase (SOD) activity-wild-type (WT) mice, mice with a targeted SOD mutation (KO, decreased CuZnSOD mRNA), and mice transgenic for SOD (TG, increased CuZnSOD mRNA). Female WT, KO (heterozygous), and TG (heterozygous) mice were given drinking water containing 20% ethanol before and throughout gestation. Non-ethanol-exposed WT, KO, and TG mice served as controls. The female mice were mated with males with identical genotype, and the pregnancy was interrupted on gestational day 18 when the offspring was evaluated and genotyped. Fetal hepatic isoprostane (8-epi-PGF(2alpha)) levels were measured to assess the degree of fetal oxidative stress. Exposure to 20% ethanol decreased fetal weight by 9-13% in the three groups. Ethanol exposure roughly doubled the rates of maldeveloped WT and KO offspring but did not affect TG offspring. The fetal hepatic levels of 8-epi-PGF(2alpha) were increased in the ethanol-exposed WT and KO mice but not in ethanol-exposed TG mice. Ethanol exposure preferentially damaged WT fetuses in pregnant KO mice, whereas no such effect was found in the litters of ethanol-consuming TG mice. Administration of ethanol to pregnant mice disturbs embryogenesis by oxidative stress, and the adverse effects are more pronounced in offspring of mice with low antioxidative capacity.

Prenatal ethanol preferentially enhances reactivity of the dopamine D1 but not D2 or D3 receptors in offspring

Reports of prenatal ethanol (ETOH) effects on the dopamine system are inconsistent. In an attempt to clarify this issue, dams were given 35% ethanol-derived calories as the sole nutrient source in a liquid diet from the 10th through the 20th day of gestation (ETOH). Controls were pair-fed (PF) an isocaloric liquid diet or given ad libitum access to laboratory chow (LC). Prenatal exposure to both liquid diets reduced body weight of offspring relative to LC controls, more so for ETOH than for PF exposure. Prenatal ETOH also decreased litter size and viability, relative to both LC and PF control groups. On postnatal days 21-23, male and female offspring were given an injection of saline vehicle or one of eight specific dopamine receptor agonists or antagonists. Immediately after injection subjects were placed in individual observation cages, and over the following 30 min, eight behaviors (square entries, grooming, rearing, circling, sniffing, yawning, head and oral movements) were observed and quantified. No prenatal treatment effects on drug-induced behaviors were observed for dopamine D2 (Apomorphine, DPAT or Quinpirole) or D3 (PD 152255, Nafadotride, Apo or Quin effects on yawning) receptor agonists or antagonists, or for the vehicle control. In contrast, prenatal treatment effects were seen with drugs affecting the dopamine D1 receptor. Both D1 agonists (SKF 38393) and antagonists (SCH 23390 and high doses of spiperone) altered behaviors, especially oral and sniffing behaviors, in a manner which suggested enhanced dopamine D1 drug sensitivity in both ETOH and PF offspring relative to LC controls. These results suggest that at this age, both sexes experience a prenatal undernutrition-linked increase in the behavioral response to dopamine D1 agonists and antagonists, which can be intensified by gestational exposure to alcohol.

Mechanisms involved in central nervous system dysfunctions induced by prenatal ethanol exposure

Clinical and experimental evidence has demonstrated that ethanol is a teratogen, and that its consumption during pregnancy induces harmful effects on the developing foetus that leads to foetal alcohol syndrome (FAS). Central nervous system dysfunctions are the most severe and permanent consequence of maternal alcohol intake and can occur in absence of gross morphological defects associated with FAS. Mental retardation and long-term cognitive and behavioural deficits are some of the problems commonly found in children of women who were moderate or heavy drinkers during pregnancy. Experimental evidence demonstrates that alcohol interferes with many molecular, neurochemical and cellular events occurring during the normal development of the brain. Some brain areas are more affected than others and, even within a given region, some cell populations are more vulnerable than others. The neocortex, hippocampus and cerebellum are especially susceptible to alcohol and have been associated with the behavioural deficits. For example, alcohol exposure during the development of neocortex increases natural apoptosis and induces cell necrosis. These effects may be associated with ethanol-induced alterations in both neurotrophic support, and the expression of cell adhesion molecules, which may affect cell-cell interactions and cell survival. Experimental evidence also shows that alcohol disrupts radial glial and astroglial development which may lead to alterations in cell migration and neuronal survival and differentiation. Impairment of several neurotransmitter systems and/or their receptors, as well as changes in the endocrine environment during brain development, are also important factors involved in the neurodevelopmental liabilities observed after in utero alcohol exposure.

Effect of maternal methionine pre-treatment on alcohol-induced exencephaly and axial skeletal dysmorphogenesis in mouse fetuses

Alcohol is known to induce folate deficiency and impair methionine synthase activity. Exogenous folic acid (FA) administered periconceptionally has been shown to prevent the first occurrence and recurrence of neural tube defects (NTD) in humans. Since folate, vitamin B(12) and methionine are metabolically interrelated, it was decided to determine the effect of methionine pre-treatment on alcohol-induced NTD and axial skeletal defects in mouse embryos. Following administration of a single dose of 70 or 150 mg/kg of methionine, 0.03 ml/g body weight of ethanol solution (25% v/v of absolute alcohol in saline) was injected intraperitoneally into pregnant mice at critical stages of neural tube development. The controls were either non-treated or saline treated and pair-fed and pair-watered. Fetuses were collected on gestation day 18. Alcohol and methionine plus alcohol numerically enhanced embryonic resorption and induced a significant reduction in fetal body weight. Alcohol alone caused a 3-fold increase in the background frequency of exencephaly in gestation days 7 and 8 treatment groups. The low dose of methionine only numerically reduced the spontaneous exencephaly. Pre-treatment with methionine only produced a numerical but not statistically significant reduction in alcohol-induced exencephaly. The higher dose of methionine did not produce a particularly beneficial effect on embryonic survival, fetal body weight and occurrence of exencephaly. Alcohol-induced cleft palate and limb malformations were ameliorated by methionine pre-treatment. Craniofacial skeleton, vertebrae and ribs were extensively malformed both in the alcohol and methionine plus alcohol groups indicating a lack of rescue effects of methionine. Whereas supernumerary ribs and extra sternal ribs were augmented by methionine, occipitalization of the atlas vertebra was a malformation unique to the pre-treatment group. Plasma levels of several amino acids including that of methionine were significantly lowered by alcohol. Pre-treatment with methionine produced a dose dependent enhancement of only methionine concentration. These data suggest that pre-administration of methionine only rescues mouse embryos of certain non-neural malformations and that the lack of ameliorative effect on NTD and axial skeletal defects may be due to the fact that alcohol lowers the concentration of a number of amino acids and therefore, supplementation should comprise a mixture of these amino acids and possibly FA and vitamin B(12).

Neuroanatomical and neurophysiological mechanisms involved in central nervous system dysfunctions induced by prenatal alcohol exposure

One of the most severe consequences of maternal ethanol consumption is the damage to the developing central nervous system, which is manifested by long-term cognitive and behavioral deficits in the offspring. Prenatal exposure to ethanol affects many crucial neurochemical and cellular components of the developing brain. Ethanol interferes with all of the stages of brain development, and the severity of the damage depends on the amount of ethanol intake and level of exposure. Experimental observations also indicate that the toxic effects of ethanol are not uniform: some brain regions are more affected than others and, even within a given region, some cell populations are more vulnerable than others. The neocortex, the hippocampus, and the cerebellum are the regions in which the neurotoxic effects of ethanol have been associated with the behavioral deficits. At the cellular level, ethanol disrupts basic developmental processes, including interference with division and proliferation, cell growth, and differentiation and the migration of maturing cells. Alterations in astroglia development and in neuronal-glial interactions may also influence the development of the nervous system. An impairment of several neurotransmitter systems and/or their receptors, as well as changes in the endocrine environment during brain development, are also important factors involved in the behavioral dysfunctions observed after prenatal ethanol exposure. Finally, some molecular mechanisms of ethanol-induced behavioral dysfunctions will be discussed.