Effect of chronic cocaine administration on amino acid uptake in rat placental membrane vesicles

The Effects of Alcohol and Drugs of Abuse on Maternal Nutritional Profile during Pregnancy

The consumption of alcohol and drugs of abuse among pregnant women has experienced a significant increase in the last decades. Suitable maternal nutritional status is crucial to maintain the optimal environment for fetal development but if consumption of alcohol or drugs of abuse disrupt the intake of nutrients, the potential teratogenic effects of these substances increase. Despite evidence of the importance of nutrition in addicted pregnant women, there is a lack of information on the effects of alcohol and drugs of abuse on maternal nutritional status; so, the focus of this review was to provide an overview on the nutritional status of addicted mothers and fetuses. Alcohol and drugs consumption can interfere with the absorption of nutrients, impairing the quality and quantity of proper nutrient and energy intake, resulting in malnutrition especially of micronutrients (vitamins, omega⁻3, folic acid, zinc, choline, iron, copper, selenium). When maternal nutritional status is compromised by alcohol and drugs of abuse the supply of essential nutrients are not available for the fetus; this can result in fetal abnormalities like Intrauterine Growth Restriction (IUGR) or Fetal Alcohol Spectrum Disorder (FASD). It is critical to find a strategy to reduce fetal physical and neurological impairment as a result of prenatal alcohol and drugs of abuse exposure combined with poor maternal nutrition. Prenatal nutrition interventions and target therapy are required that may reverse the development of such abnormalities.

Cocaine and its metabolites in the placenta: a systematic review of the literature

It is clear that cocaine and cocaine metabolites are present in the placenta and may harm the fetus. The results of the experimental manipulation of cocaine exposure are not reported in the literature in a consistent manner. We conducted a systematic review of selected articles that demonstrated the analytical detection of cocaine and its metabolites in the placenta and that were published from January 1, 1956-June 30, 2011 using Medline, Toxline and Scopus databases. The collected data confirm that the placenta does not act as a barrier to fetal exposure, that cocaine quickly crosses the placenta and that one of the essential roles of the placenta is to metabolize cocaine during pregnancy. Our systematic review summarized the results showing that cocaine, benzoylecgonine and norcocaine are stored in the myometrium and the placental membrane and maintain continuous drug delivery to the amniotic fluid (and to the fetus) probably via diffusion.

National Institute on Drug Abuse Conference report on placental proteins, drug transport, and fetal development

The use of illicit and licit drugs during pregnancy is a major public health concern because of potential adverse effects on the fetus and the risk to maternal health. Because the placenta is the primary link between the mother and the conceptus and is essential for the growth and survival of the fetus, abnormalities in placental formation and function resulting from drug use could have a major influence on pregnancy outcome. At present, little information is available on the impact of abused drugs on placental biology alone or in combination with other "host" factors (eg, stress, infections). This prompted the National Institute on Drug Abuse (NIDA) to convene a meeting of experts in placental biology to review cutting-edge research with the mission to translate existing information to new clinical and research initiatives in the drug abuse field. This report summarizes the presentations and research recommendations resulting from the workshop discussions.

The role of system A for neutral amino acid transport in the regulation of cell volume

System A is a secondary active, sodium dependent transport system for neutral amino acids. Strictly coupled with Na,K-ATPase, its activity determines the size of the intracellular amino acid pool, through a complex network of metabolic reaction and exchange fluxes. Many hormones and drugs affect system A activity in specific cell models or tissues. In all the cell models tested thus far the activity of the system is stimulated by amino acid starvation, cell cycle progression, and the incubation under hypertonic conditions. These three conditions produce marked alterations of cell volume. The stimulation of system A activity plays an important role in cell volume restoration, through an expansion of the intracellular amino acid pool. Under normal conditions, system A substrates represent a major fraction of cell compatible osmolytes, organic compounds that exert a protein stabilizing effect. It is, therefore, likely that the activation of system A represents a portion of a more complex response triggered by exposure to stresses of various nature. Since system A transporters have been recently cloned, the molecular bases of these regulatory mechanisms will probably be elucidated in a short time.

Maternal cocaine use and cigarette smoking in pregnancy in relation to amino acid transport and fetal growth

This review covers the weight of evidence that shows the association of cocaine and cigarette smoking in pregnancy with the impaired transplacental amino acid transport which might give rise to fetal growth restriction (IUGR). Vasoconstrictive effects of both cocaine and nicotine on the placental vasculature are clearly not the only cause for inhibition of placental amino acid uptake and transfer. In vitro studies strongly suggest that cocaine decreases the activity of placental amino acid transport system A and system N, and possibly system l and system y(+), while nicotine decreases the activity of system A. These findings are supported by cordocentesis studies in human IUGR pregnancies not resulting from drug abuse. More work is needed to be done in order to understand the potential additive or synergistic effect of cocaine and cigarette smoking on fetal growth and to determine the underlying cellular mechanisms of interaction with placental amino acid transporters.

Drugs of abuse and placental transport

The placenta provides the only link between the mother and the developing fetus. The function of the placenta as a transport organ is obligatory for fetal development because this process, mediated by a variety of transport systems, is responsible for the delivery of nutrients from the mother to the fetus. Some of the transport systems in the placenta also play a role in the clearance of vasoactive compounds, thus maintaining optimal blood flow to this organ. There is strong supporting evidence to indicate that several of these placental transport systems are either direct or indirect targets for the abusable drugs cocaine, amphetamines, nicotine, and cannabinoids. These drugs of abuse compromise the placental transport function and consequently produce detrimental effects on the developing fetus.

Prenatal cocaine, alcohol, and undernutrition differentially alter mineral and protein content in fetal rats

Alcohol exposure and undernutrition during pregnancy have been associated with altered fetal body composition. Recent observations suggest that cocaine exposure during pregnancy may impair delivery of nutrients to the fetus and could thereby alter body growth and composition. Such effects are important because they can adversely influence physical and neural development. Consequently, we investigated the dose-dependent effects of cocaine on fetal body composition in an animal (rat) model and compared such effects with those caused by prenatal alcohol exposure and undernutrition. Pregnant Sprague-Dawley rats received either 20, 30, 40, or 50 mg/kg cocaine HCl (SC) twice daily from gestation days 7 through 19. Pair-fed (undernutrition) and untreated control groups and a group receiving 3.0 g/kg alcohol (PO) twice daily served as comparison groups (n = 11 to 14/group). Females were sacrificed on gestation day 20. One male and one female fetus was removed from each dam. The fetuses were minced, dehydrated, defatted, and analyzed for content of protein and the minerals Zn, Ca, Fe, Mg, K, and Na. In terms of concentration per unit of fat-free dry solids, male fetuses in the cocaine groups showed significant decreases in protein compared to untreated controls (15+/-3 to 20+/-2 mg/g vs. 24+/-4 mg/g, p = 0.01). There was a significant treatment effect for Ca (p < 0.05), reflecting a trend for decreased Ca concentrations in the fetuses of the cocaine and undernutrition groups. Male fetuses in the alcohol group had significantly elevated Mg levels compared to male fetuses in the other groups (3.0+/-0.8 vs. 1.0+/-0.2 to 2.3+/-0.7 mg/g, p < 0.05). There were some sex differences, with female fetuses having significantly lower concentrations of Mg, Fe, K, and higher protein concentrations than male fetuses. Although the effects were few and modest, these results suggest that prenatal cocaine, alcohol, and undernutrition can differentially alter fetal body weight and composition and, therefore, adversely influence fetal development.

Permeability properties of monolayers of the human trophoblast cell line BeWo

The BeWo cell line (b30 clone) has been examined as a potential in vitro system to study transplacental transport. At the light and electron microscope level, the cells were observed to form confluent monolayers on polycarbonate filters in approximately 5 days and morphologically resembled the typical human trophoblast. BeWo monolayers developed a modest transepithelial electrical resistance and a molecular size-dependent permeability to hydrophilic passive diffusion markers, fluorescein, and selected fluorescein-labeled dextrans. Linoleic acid permeation across BeWo monolayers was asymmetric, saturable, and inhibited by low temperature and excess competing fatty acid. Forskolin and 8-bromoadenosine 3',5'-cyclic monophosphate treatments stimulated morphological changes in BeWo cultures and enhanced the asymmetric passage of linoleic acid across the BeWo monolayers while having minimal effects on passive permeability, affirming that the differentiation state of the cells can influence membrane transporters and transmonolayer permeability. The basic permeability properties of the BeWo monolayers suggest that the cells grown on permeable supports may be examined as a convenient in vitro system to evaluate some transplacental transport mechanisms.