Fetal Alcohol Spectrum Disorders: Characteristics, Complications, and Treatment

Fetal Cerebral Circulation as Target of Maternal Alcohol Consumption

Alcohol (ethanol [EtOH]) is one of the most widely used psychoactive substances worldwide. Alcohol consumption during pregnancy may result in a wide range of morphological and neurodevelopmental abnormalities termed fetal alcohol spectrum disorders (FASD), with the most severe cases diagnosed as fetal alcohol syndrome (FAS). FAS and FASD are not readily curable and currently represent the leading preventable causes of birth defect and neurodevelopmental delay in the United States. The etiology of FAS/FASD remains poorly understood. This review focuses on the effects of prenatal alcohol exposure (PAE) on fetal cerebrovascular function. A brief introduction to the epidemiology of alcohol consumption and the developmental characteristics of fetal cerebral circulation is followed by several sections that discuss current evidence documenting alcohol-driven alterations of fetal cerebral blood flow, artery function, and microvessel networks. The material offers mechanistic insights at the vascular level itself into the pathophysiology of PAE.

The role of folic acid and selenium against oxidative damage from ethanol in early life programming: a review

There are disorders in children, covered by the umbrella term “fetal alcohol spectrum disorder” (FASD), that occur as result of alcohol consumption during pregnancy and lactation. They appear, at least in part, to be related to the oxidative stress generated by ethanol. Ethanol metabolism generates reactive oxygen species and depletes the antioxidant molecule glutathione (GSH), leading to oxidative stress and lipid and protein damage, which are related to growth retardation and neurotoxicity, thereby increasing the incidence of FASD. Furthermore, prenatal and postnatal exposure to ethanol in dams, as well as increasing oxidation in offspring, causes malnutrition of several micronutrients such as the antioxidant folic acid and selenium (Se), affecting their metabolism and bodily distribution. Although abstinence from alcohol is the only way to prevent FASD, it is possible to reduce its harmful effects with a maternal dietary antioxidant therapy. In this review, folic acid and Se have been chosen to be analyzed as antioxidant intervention systems related to FASD because, like ethanol, they act on the methionine metabolic cycle, being related to the endogenous antioxidants GSH and glutathione peroxidase. Moreover, several birth defects are related to poor folate and Se status.

Nifedipine Prevents Apoptosis of Alcohol-Exposed First-Trimester Trophoblast Cells

BACKGROUND

Maternal alcohol abuse leading to fetal alcohol spectrum disorder (FASD) includes fetal growth restriction (FGR). Ethanol (EtOH) induces apoptosis of human placental trophoblast cells, possibly disrupting placentation and contributing to FGR in FASD. EtOH facilitates apoptosis in several embryonic tissues, including human trophoblasts, by raising intracellular Ca²⁺ . We previously found that acute EtOH exposure increases trophoblast apoptosis due to signaling from both intracellular and extracellular Ca²⁺ . Therefore, nifedipine, a Ca²⁺ channel blocker that is commonly administered to treat preeclampsia and preterm labor, was evaluated for cytoprotective properties in trophoblast cells exposed to alcohol.

METHODS

Human first-trimester chorionic villous explants and the human trophoblast cell line HTR-8/SVneo (HTR) were pretreated with 12.5 to 50 nM of the Ca²⁺ channel blocker nifedipine for 1 hour before exposure to 50 mM EtOH for an additional hour. Intracellular Ca²⁺ concentrations were monitored in real time by epifluorescence microscopy, using fluo-4-AM. Apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), accumulation of cytoplasmic cytochrome c, and cleavage rates of caspase 3 and caspase 9.

RESULTS

The increase in intracellular Ca²⁺ upon exposure to EtOH in both villous explants and HTR cells was completely blocked (p < 0.05) when pretreated with nifedipine, accompanied by inhibition of EtOH-induced release of cytochrome c, caspase activities, and TUNEL.

CONCLUSIONS

This study indicates that nifedipine can interrupt the apoptotic pathway downstream of EtOH exposure and could provide a novel strategy for future interventions in women with fetuses at risk for FASD.

Fetal Alcohol Exposure: The Common Toll

Alcohol has always been present in human life, and currently it is estimated that 50% of women of childbearing age consume alcohol. It has become increasingly clear over the last years that alcohol exposure during fetal development can have detrimental effects on various organ systems, and these effects are exerted by alcohol through multiple means, including effects on free radical formation, cellular apoptosis, as well as gene expression. Fetal alcohol exposure can lead to a spectrum of short term as well as long-term problems, with Fetal Alcohol Syndrome being on the more severe end of that spectrum. This syndrome is morbid, yet preventable, and is characterized by midfacial hypoplasia, thin upper lip, widely spaced small eyes, long smooth philtrum and inner epicanthal folds. Other findings include growth restriction as well as various neurodevelopmental abnormalities. This article is the first comprehensive review combining the molecular as well as the gross physiological and anatomical effects of alcohol exposure during pregnancy on various organ systems in the body. Our knowledge of these various mechanisms is crucial for our understanding of how alcohol exposure during fetal development can lead to its detrimental effects.