Impact of adolescent intermittent ethanol exposure on interneurons and their surrounding perineuronal nets in adulthood.

Background: Binge alcohol exposure during adolescence results in long-lasting alterations in brain and behavior. For example, adolescent intermittent ethanol (AIE) exposure in rodents results in long-term loss of functional connectivity among prefrontal cortex (PFC) and striatal regions as well as a variety of neurochemical, molecular, and epigenetic alterations. Interneurons in the PFC and striatum play critical roles in behavioral flexibility and functional connectivity. For example, parvalbumin (PV) interneurons are known to contribute to neural synchrony, and cholinergic interneurons contribute to strategy selection. Furthermore, extracellular perineuronal nets (PNNs) surround some interneurons, particularly PV+ interneurons, to further regulate cellular plasticity. The effect of AIE exposure on expression of these markers within the PFC is not well understood. Methods: The present study tested the hypothesis that AIE exposure reduces expression of PV+ and ChAT+ interneurons in the adult PFC and striatum and increases related expression of PNNs (marked by binding of Wisteria Floribunda agglutinin lectin; WFA) in adulthood. Male rats were exposed to AIE (5 g/kg/day, 2-days-on/2-days-off, i.g., P25-P54) or water (CON), and brain tissue was harvested in adulthood (> P80). Immunohistochemistry and co-immunofluorescence were used to assess expression of ChAT, PV, and WFA labeling within the adult PFC and striatum following AIE exposure. Results: ChAT and PV interneuron numbers in the striatum and PFC were unchanged after AIE exposure. However, WFA labeling in the PFC of AIE-exposed rats was increased compared to CON rats. Moreover, significantly more PV neurons were surrounded by WFA labeling in AIE-exposed subjects relative to controls in both PFC subregions assessed: the orbitofrontal cortex (CON = 34%; AIE = 40%) and the medial PFC (CON = 10%; AIE = 14%). Conclusions: These findings indicate that while PV interneuron expression in the adult PFC and striatum is unaltered following AIE exposure, PNNs surrounding these neurons (indicated by extracellular WFA binding) are increased. This increase in PNNs may restrict plasticity of the ensheathed neurons, thus contributing to impaired microcircuitry in frontostriatal connectivity and related behavioral impairments.

Ethanol Exposure During the Intravenous Administration of Chemotherapeutic Drugs: An Analysis of Clinical Practice and a Literature Review

PURPOSE: Injectable cytotoxics may be formulated with ethanol. This study sought to quantify the amount of ethanol exposure during chemotherapy infusions. MATERIALS AND METHODS: We first reviewed the antineoplastic drugs (Anatomical Therapeutic and Chemical code L01) and oncologic supportive care drugs (eg, antiemetics) currently available in France, to identify preparations containing ethanol. The amount of ethanol in the final chemotherapy preparation was calculated. Next, we performed a 2-year, single-center, retrospective analysis of injectable antineoplastic drug compounding in routine clinical practice in a French university medical center. Finally, we reviewed our results with regard to the literature data. RESULTS: Ten of the 60 cytotoxic products on the market contained ethanol at concentrations of up to 790 mg/mL, depending on the drug, formulation, and supplier. Several final preparations contained more than 3 g of ethanol per infusion (the maximum recommended by the European Medicines Agency); this was notably the case for gemcitabine, paclitaxel (up to 20 g ethanol per injection, for both), and etoposide (up to 50 g ethanol per infusion). The analysis of our compounding activity showed that 3,172 (4.99%) of the 63,613 chemotherapy preparations (notably paclitaxel) contained more than 3 g of ethanol. None of the oncologic supportive care drugs contained ethanol. CONCLUSION: Patients are exposed to ethanol during the infusion of antineoplastic drugs. With a view to better patient care, physicians and pharmacists should carefully evaluate the risk of ethanol exposure throughout the course of cytotoxic drug treatment.

Cortical Neurons and Astrocytes in Intrauterine Ethanol Exposure: The Role of Exposure Time and Postnatal Timeline

Background: The state of cortical neurons and astrocytes are pointers to the health of the brain. These cells are morphologically distorted by alcohol exposure. Intrauterine alcohol exposure remains a challenge with perinatal consequences. The role of exposure time and postnatal timeline on the degree of cortical cell derangement remains a subject of controversy till date. This study therefore examines alcohol exposure and postnatal changes on brain weight, cortical neurons and astrocytes at different developmental periods. Methods: Twenty mature female Wistar rats were time-mated and grouped into 4 groups. Group 1 (control) received distilled water (2 mL/kg), Groups 2, 3 and 4 were administered 2.5 mL/kg of 20% ethanol orally on the 4th, 11th and 18th days of gestation respectively. Rats produced litters and pups' brains were harvested and processed for H&E and Golgi Cox stains at the 3rd and 6th postnatal week. Neuronal and astrocytic densities in the cerebral cortex were evaluated. Results and Conclusion: There was statistically significant increase (p<0.05) in the density of degenerating neurons at the third postnatal week and sixth postnatal weeks in the experimental groups when compared with the control. There was also statistically significant increase (p<0.05) in astrocytic density in groups 2 and 4 at the 3rd postnatal week. There was no statistically significant difference (p>0.05) in the astrocytic densities across groups at the sixth postnatal week. It was concluded that intrauterine alcohol exposure in any of the developmental periods resulted in postnatal neuronal degeneration which persisted till the 6th week. However, increased astrocytic densities is a feature of 1st and 3rd trimester alcohol exposure noted in the 3rd but absent in the 6th postnatal week.

Acute Ethanol Exposure during Synaptogenesis Rapidly Alters Medium Spiny Neuron Morphology and Synaptic Protein Expression in the Dorsal Striatum

Fetal alcohol spectrum disorders are caused by the disruption of normal brain development in utero. The severity and range of symptoms is dictated by both the dosage and timing of ethanol administration, and the resulting developmental processes that are impacted. In order to investigate the effects of an acute, high-dose intoxication event on the development of medium spiny neurons (MSNs) in the striatum, mice were injected with ethanol on P6, and neuronal morphology was assessed after 24 h, or at 1 month or 5 months of age. Data indicate an immediate increase in MSN dendritic length and branching, a rapid decrease in spine number, and increased levels of the synaptic protein PSD-95 as a consequence of this neonatal exposure to ethanol, but these differences do not persist into adulthood. These results demonstrate a rapid neuronal response to ethanol exposure and characterize the dynamic nature of neuronal architecture in the MSNs. Although differences in neuronal branching and spine density induced by ethanol resolve with time, early changes in the caudate/putamen region have a potential impact on the execution of complex motor skills, as well as aspects of long-term learning and addictive behavior.

Behavioural and molecular effects of alcohol in the stress model of zebrafish

Objectives: Stress and anxiety disorders are common health problems that have been related to an increase in the likelihood of developing addictions, which have individual and social consequences. Although socially acceptable, alcohol is a substance that can generate dependence and abuse. Alcohol misuse, its relationship with stress and its consequences have been studied; however, multiple limitations are placed on clinical research in humans. In this exploratory work, we analysed the behavioural and molecular effects of joint exposure to ethanol and an unpredictable stress protocol (USP) in adult zebrafish. Materials and Methods: Adult zebrafish behaviour was studied employing unpredictable stress and behavioural tests. The tests were performed in stressed and nonstressed animals with and without exposure to known concentrations of alcohol. To evaluate the behaviour, tracking techniques were used on video recordings and parameters such as distance travelled, swimming speed and place preference as well as aggression patterns with mirror proximity tests were measured. In the control and 0.75% alcohol group, the expression of candidate stress-related genes (slc6a4a, slc6a3, comta and bdnf3) was analysed by RT-qPCR. Results: The results showed that concentrations of 0.75% alcohol reduced the locomotor activity of the fish, which can be interpreted as an increase in the anxiolytic effect of alcohol under nonstress conditions. Expression of comta, bdnf3 and slc6a3 was reduced in the stress and stress plus 0.75% ethanol groups and expression of slc6a4a was increased in the stress plus 0.75% alcohol group. Conclusion: Our exploratory work contributes novel insights about the molecular and behavioural effects of the combination of unpredicted stress and alcohol misuse. The USP and ethanol exposure increase anxiety behaviour and reduce the expression of genes involved in brain homeostasis. Future study of other pharmacological compounds and additional genes will be helpful for a deeper understanding of the molecular mechanisms involved in the response to stress and alcohol use.

Methylmercury plus Ethanol Exposure: How Much Does This Combination Affect Emotionality?

Mercury is a heavy metal found in organic and inorganic forms that represents an important toxicant with impact on human health. Mercury can be released in the environment by natural phenoms (i.e., volcanic eruptions), industrial products, waste, or anthropogenic actions (i.e., mining activity). Evidence has pointed to mercury exposure inducing neurological damages related to emotional disturbance, such as anxiety, depression, and insomnia. The mechanisms that underlie these emotional disorders remain poorly understood, although an important role of glutamatergic pathways, alterations in HPA axis, and disturbance in activity of monoamines have been suggested. Ethanol (EtOH) is a psychoactive substance consumed worldwide that induces emotional alterations that have been strongly investigated, and shares common pathophysiological mechanisms with mercury. Concomitant mercury and EtOH intoxication occur in several regions of the world, specially by communities that consume seafood and fish as the principal product of nutrition (i.e., Amazon region). Such affront appears to be more deleterious in critical periods of life, such as the prenatal and adolescence period. Thus, this review aimed to discuss the cellular and behavioral changes displayed by the mercury plus EtOH exposure during adolescence, focused on emotional disorders, to answer the question of whether mercury plus EtOH exposure intensifies depression, anxiety, and insomnia observed by the toxicants in isolation.