Fetal Cerebral Artery Mitochondrion as Target of Prenatal Alcohol Exposure

Parental Alcohol Exposures Associate with Lasting Mitochondrial Dysfunction and Accelerated Aging in a Mouse Model

Although detrimental changes in mitochondrial morphology and function are widely described symptoms of fetal alcohol exposure, no studies have followed these mitochondrial deficits into adult life or determined if they predispose individuals with fetal alcohol spectrum disorders (FASDs) to accelerated biological aging. Here, we used a multiplex preclinical mouse model to compare markers of cellular senescence and age-related outcomes induced by maternal, paternal, and dual-parental alcohol exposures. We find that even in middle life (postnatal day 300), the adult offspring of alcohol-exposed parents exhibited significant increases in markers of stress-induced premature cellular senescence in the brain and liver, including an upregulation of cell cycle inhibitory proteins and increased senescence-associated β-galactosidase activity. Strikingly, in the male offspring, we observe an interaction between maternal and paternal alcohol use, with histological indicators of accelerated age-related liver disease in the dual-parental offspring exceeding those induced by either maternal or paternal alcohol use alone. Our studies indicate that chronic parental alcohol use causes enduring mitochondrial dysfunction in offspring, resulting in a reduced NAD+/NAHD ratio and altered expression of the NAD+-dependent deacetylases SIRT1 and SIRT3. These observations suggest that some aspects of FASDs may be linked to accelerated aging due to programmed changes in the regulation of mitochondrial function and cellular bioenergetics.

In utero ethanol exposure induces mitochondrial DNA damage and inhibits mtDNA repair in developing brain

Introduction

Mitochondrial dysfunction is postulated to be a central event in fetal alcohol spectrum disorders (FASD). People with the most severe form of FASD, fetal alcohol syndrome (FAS) are estimated to live only 34 years (95% confidence interval, 31 to 37 years), and adults who were born with any form of FASD often develop early aging. Mitochondrial dysfunction and mitochondrial DNA (mtDNA) damage, hallmarks of aging, are postulated central events in FASD. Ethanol (EtOH) can cause mtDNA damage, consequent increased oxidative stress, and changes in the mtDNA repair protein 8-oxoguanine DNA glycosylase-1 (OGG1). Studies of molecular mechanisms are limited by the absence of suitable human models and non-invasive tools.

Methods

We compared human and rat EtOH-exposed fetal brain tissues and neuronal cultures, and fetal brain-derived exosomes (FB-Es) from maternal blood. Rat FASD was induced by administering a 6.7% alcohol liquid diet to pregnant dams. Human fetal (11-21 weeks) brain tissue was collected and characterized by maternal self-reported EtOH use. mtDNA was amplified by qPCR. OGG1 and Insulin-like growth factor 1 (IGF-1) mRNAs were assayed by qRT-PCR. Exosomal OGG1 was measured by ddPCR.

Results

Maternal EtOH exposure increased mtDNA damage in fetal brain tissue and FB-Es. The damaged mtDNA in FB-Es correlated highly with small eye diameter, an anatomical hallmark of FASD. OGG1-mediated mtDNA repair was inhibited in EtOH-exposed fetal brain tissues. IGF-1 rescued neurons from EtOH-mediated mtDNA damage and OGG1 inhibition.

Conclusion

The correlation between mtDNA damage and small eye size suggests that the amount of damaged mtDNA in FB-E may serve as a marker to predict which at risk fetuses will be born with FASD. Moreover, IGF-1 might reduce EtOH-caused mtDNA damage and neuronal apoptosis.

Oxidative Stress in a Mother Consuming Alcohol during Pregnancy and in Her Newborn: A Case Report

Fetal alcohol spectrum disorder (FASD) is a set of conditions resulting from prenatal alcohol exposure (PAE). FASD is estimated to affect between 2% and 5% of people in the United States and Western Europe. The exact teratogenic mechanism of alcohol on fetal development is still unclear. Ethanol (EtOH) contributes to the malfunctioning of the neurological system in children exposed in utero by decreasing glutathione peroxidase action, with an increase in the production of reactive oxygen species (ROS), which causes oxidative stress. We report a case of a mother with declared alcohol abuse and cigarette smoking during pregnancy. By analyzing the ethyl glucuronide (EtG, a metabolite of alcohol) and the nicotine/cotinine in the mother's hair and meconium, we confirmed the alcohol and smoking abuse magnitude. We also found that the mother during pregnancy was a cocaine abuser. As a result, her newborn was diagnosed with fetal alcohol syndrome (FAS). At the time of the delivery, the mother, but not the newborn, had an elevation in oxidative stress. However, the infant, a few days later, displayed marked potentiation in oxidative stress. The clinical complexity of the events involving the infant was presented and discussed, underlining also the importance that for cases of FASD, it is crucial to have more intensive hospital monitoring and controls during the initial days.

Path analysis of the impact of prenatal alcohol on adult vascular function

BACKGROUND

The vascular system may be particularly vulnerable to prenatal alcohol exposure (PAE). Alterations in angiogenesis and epigenetic changes to vascular development have been implicated as a probable mechanism for this vulnerability.

METHODS

We assessed the long-term impact of prenatal alcohol exposure (PAE) on adult vascular health using a prospective cohort first identified while in utero. Participants with no PAE (n = 37, mean age = 36.7 [SD = 1.6] years) were compared to participants with PAE (n = 51, mean age = 36.3 [SD = 1.7] years). Their vascular health was assessed by arterial blood pressure (BP) and peripheral arterial tonometry, which yields an index of endothelial function (reactive hyperemia index) and a measure of arterial stiffness (augmentation index). Blood samples were collected to assess cholesterol levels and insulin resistance (glucose, hemoglobin A1C, and insulin). Path analysis was used to examine the direct and indirect effects of PAE on vascular health after adjusting for other known physical outcomes.

RESULTS

Participants with a history of PAE weighed less, trended towards being shorter, had smaller body mass, and had more alcohol-related dysmorphic features than those without PAE. Path analysis suggested that the impact of PAE on BP was through its indirect relationships with height, body mass index, and dysmorphic features and resulted in protective effects relative to the Contrast group who were disproportionately overweight. PAE was also found to have a direct negative effect on endothelial function. An index of total alcohol-related dysmorphic features was negatively had both a direct effect on arterial stiffness and an indirect effect on endothelial function.

CONCLUSIONS

Prenatal alcohol exposures' impact on vascular function is not independent of other common physical and environmental factors but endothelial function and arterial stiffness seemed most compromised after controlling for these other factors. Level of alcohol-related dysmorphic features seems to be predictive of more adverse effects than endothelial function and vascular stiffness.

Mechanisms Underlying Cognitive Impairment Induced by Prenatal Alcohol Exposure

Alcohol is one of the most commonly used illicit substances among pregnant women. Clinical and experimental studies have revealed that prenatal alcohol exposure affects fetal brain development and ultimately results in the persistent impairment of the offspring's cognitive functions. Despite this, the rate of alcohol use among pregnant women has been progressively increasing. Various aspects of human and animal behavior, including learning and memory, are dependent on complex interactions between multiple mechanisms, such as receptor function, mitochondrial function, and protein kinase activation, which are especially vulnerable to alterations during the developmental period. Thus, the exploration of the mechanisms that are altered in response to prenatal alcohol exposure is necessary to develop an understanding of how homeostatic imbalance and various long-term neurobehavioral impairments manifest following alcohol abuse during pregnancy. There is evidence that prenatal alcohol exposure results in vast alterations in mechanisms such as long-term potentiation, mitochondrial function, and protein kinase activation in the brain of offspring. However, to the best of our knowledge, there are very few recent reviews that focus on the cognitive effects of prenatal alcohol exposure and the associated mechanisms. Therefore, in this review, we aim to provide a comprehensive summary of the recently reported alterations to various mechanisms following alcohol exposure during pregnancy, and to draw potential associations with behavioral changes in affected offspring.

Prenatal exposure to alcohol: mechanisms of cerebral vascular damage and lifelong consequences

Alcohol is a well-known teratogen, and prenatal alcohol exposure (PAE) leads to a greater incidence of many cardiovascular-related pathologies. Alcohol negatively impacts vasculogenesis and angiogenesis in the developing fetal brain, resulting in fetal alcohol spectrum disorders (FASD). Ample preclinical evidence indicates that the normal reactivity of cerebral resistance arterioles, which regulate blood flow distribution in response to metabolic demand (neurovascular coupling), is impaired by PAE. This impairment of dilation of cerebral arteries may carry implications for the susceptibility of the brain to cerebral ischemic damage well into adulthood. The focus of this review is to consolidate findings from studies examining the influence of PAE on vascular development, give insights into relevant pathological mechanisms at the vascular level, evaluate the risks of ethanol-driven alterations of cerebrovascular reactivity, and revisit different preventive interventions that may have promise in reversing vascular changes in preclinical FASD models.

Aversive Learning Deficits and Depressive-Like Behaviors Are Accompanied by an Increase in Oxidative Stress in a Rat Model of Fetal Alcohol Spectrum Disorders: The Protective Effect of Rapamycin

Fetal alcohol spectrum disorders (FASDs) are one of the most common consequences of ethanol exposure during pregnancy. In adulthood, these disorders can be manifested by learning and memory deficits and depressive-like behavior. Ethanol-induced oxidative stress may be one of the factors that induces FASD development. The mammalian target of the Rapamycin (mTOR) signaling pathway that acts via two distinct multiprotein complexes, mTORC1 and mTORC2, can affect oxidative stress. We investigated whether mTOR-dependent or mTOR-independent mechanisms are engaged in this phenomenon. Thus, Rapamycin—a selective inhibitor of mTORC1, Torin-2—a non-selective mTORC1/mTORC2 inhibitor, and FK-506—a drug that impacts oxidative stress in an mTOR-independent manner were used. Behavioral tests were performed in adult (PND60-65) rats using a passive avoidance (PA) task (aversive learning and memory) and forced swimming test (FST) (depressive-like behaviors). In addition, the biochemical parameters of oxidative stress, such as lipid peroxidation (LPO), as well as apurinic/apyrimidinic (AP)-sites were determined in the hippocampus and prefrontal cortex in adult (PND65) rats. The rat FASD model was induced by intragastric ethanol (5 g/kg/day) administration at postnatal day (PND)4–9 (an equivalent to the third trimester of human pregnancy). All substances (3 mg/kg) were given 30 min before ethanol. Our results show that neonatal ethanol exposure leads to deficits in context-dependent fear learning and depressive-like behavior in adult rats that were associated with increased oxidative stress parameters in the hippocampus and prefrontal cortex. Because these effects were completely reversed by Rapamycin, an mTORC1 inhibitor, this outcome suggests its usefulness as a preventive therapy in disorders connected with prenatal ethanol exposure.

Alcohol use in pregnancy and its impact on the mother and child

AIMS

To review the impact of prenatal alcohol exposure on the outcomes of the mother and child.

DESIGN

Narrative review.

SETTING

Review of literature.

PARTICIPANTS

Mothers and infants affected by prenatal alcohol use.

MEASUREMENTS

Outcomes of mothers and children.

FINDINGS

Prenatal alcohol exposure is one of the most important causes of preventable cognitive impairment in the world. The developing neurological system is exquisitely sensitive to harm from alcohol and there is now also substantial evidence that alcohol-related harm can extend beyond the individual person, leading to epigenetic changes and intergenerational vulnerability and disadvantage. There is no known safe level or timing of drinking for pregnant or lactating women and binge drinking (> four drinks within 2 hours for women) is the most harmful. Alcohol-exposure increases the risk of congenital problems, including Fetal Alcohol Spectrum Disorder (FASD) and its most severe form, Fetal Alcohol Syndrome (FAS).

CONCLUSION

The impact of FASD and FAS is enduring and life-long with no current treatment or cure. Emerging therapeutic options may mitigate the worst impact of alcohol exposure but significant knowledge gaps remain. This review discusses the history, epidemiology and clinical presentations of prenatal alcohol exposure, focusing on FASD and FAS, and the impact of evidence on future research, practice and policy directions.

Fetal alcohol spectrum disorders model alters the functionality of glutamatergic neurotransmission in adult zebrafish

Fetal alcohol spectrum disorders (FASD) describe a wide range of ethanol-induced developmental disabilities, including craniofacial dysmorphology, and neurochemical and behavioral impairments. Zebrafish has become a popular animal model to evaluate the long-lasting effects of, both, severe and milder forms of FASD, including alterations to neurotransmission. Glutamate is one of the most affected neurotransmitter systems in ethanol-induced developmental disabilities. Therefore, the aim of the present study was to evaluate the functionality of the glutamatergic neurotransmitter system in an adult zebrafish FASD model. Zebrafish larvae (24 h post-fertilization) were exposed to ethanol (0.1 %, 0.25 %, 0.5 %, and 1%) for 2 h. After 4 months, the animals were euthanized and their brains were removed. The following variables were measured: glutamate uptake, glutamate binding, glutamine synthetase activity, Na+/K + ATPase activity, and high-resolution respirometry. Embryonic ethanol exposure reduced Na+-dependent glutamate uptake in the zebrafish brain. This reduction was positively modulated by ceftriaxone treatment, a beta-lactam antibiotic that promotes the expression of the glutamate transporter EAAT2. Moreover, the 0.5 % and 1% ethanol groups demonstrated reduced glutamate binding to brain membranes and decreased Na+/K + ATPase activity in adulthood. In addition, ethanol reduced glutamine synthetase activity in the 1% EtOH group. Embryonic ethanol exposure did not alter the immunocontent of the glutamate vesicular transporter VGLUT2 and the mitochondrial energetic metabolism of the brain in adulthood. Our results suggest that embryonic ethanol exposure may cause significant alterations in glutamatergic neurotransmission in the adult zebrafish brain.

Fetal Alcohol Spectrum Disorders: Fixing Our Aim to Aim for the Fix

We, as editors of this special issue on Fetal Alcohol Spectrum Disorders (FASD), are proud to present eleven papers [...].