Reduction of brain mitochondrial β-oxidation impairs complex I and V in chronic alcohol intake: the underlying mechanism for neurodegeneration

Fermented Protaetia brevitarsis Larvae Improves Neurotoxicity in Chronic Ethanol-Induced-Dementia Mice via Suppressing AKT and NF-κB Signaling Pathway

This study was investigated to examine the neuroprotective effect of fermented Protaetia brevitarsis larvae (FPB) in ethanol-induced-dementia mice. Consumption of FPB by mice resulted in improved memory dysfunction in the Y-maze, passive avoidance, and Morris water maze tests. FPB significantly decreased oxidative stress by regulating levels of malondialdehyde (MDA), superoxide dismutase (SOD), and reduced glutathione (GSH) in brain tissues. In addition, FPB restored cerebral mitochondrial dysfunction by modulating levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP. In addition, FPB enhanced the cholinergic system via the regulation of acetylcholine (ACh) content, acetylcholinesterase (AChE) activity, and expressions of AChE and choline acetyltransferase (ChAT) in brain tissues. FPB ameliorated neuronal apoptosis through modulation of the protein kinase B (AKT)/B-cell lymphoma (BCL)-2 signaling pathway. Also, FPB improved inflammation response by down-regulating the toll-like receptor (TLR)-4/nuclear factor (NF)-κB pathway. Additionally, FPB ameliorated synaptic plasticity via the increase of the expressions of synaptophysin (SYP), postsynaptic density protein (PSD)-95, and growth-associated protein (GAP)-43. Treatment with FPB also reinforced the blood-brain barrier by increasing tight junctions including zonula occludens (ZO)-1, occludin, and claudin-1. In conclusion, these results show that FPB can improve cognitive impairment via AKT/NF-κB pathways in ethanol-induced-dementia mice.

Ameliorative effect of diazepam against ethanol-induced mitochondrial disruption in brains of the mice

Brain oxidative damage and neurodegeneration by ethanol (ETH) are considered as important factors that triggered by oxidative stress. Recently, the abuse of diazepam (DZM) has increased by alcoholism-addicted patients. The present study evaluated the effects of combination treatment of ETH with DZM on oxidative damage induced in brain mitochondria of the mice. Only ETH (0.3, 0.6, and 2.5 g / kg) and ETH+ DZM (2.5 mg / kg) were administered intraperitoneally (ip) to the mice. Pathological changes and oxidative stress biomarkers including ROS, lipid peroxidation, carbonyl protein, mitochondrial function, and glutathione content were evaluated in brain mitochondria after 42 days. Results indicated that co-treatment of DZM and ETH significantly reduced mitochondrial toxicity, oxidative damage, pathological changes and increased level of glutathione. Subchronic ETH administration induced brain oxidative damage, mitochondrial disruption, and serious damage to the brain cells. Whereas, combination treatment improved oxidative damage, mitochondrial function, and pathological changes in brain cells after intoxication by ETH. These findings suggest antioxidant effect of DZM in combination with ETH and can be considered in reducing oxidative stress and mitochondrial damage attenuation in the brain. Combination therapy may be a better therapeutic candidate for prevention of brain oxidative damage induced by ETH.

Substance abuse and neurodegenerative diseases: focus on ferroptosis

Psychostimulants and alcohol are widely abused substances with the adverse effects on global public health. Substance abuse seriously harms people's health and causes various diseases, especially neurodegenerative diseases. Neurodegenerative diseases include Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). The pathogenesis of neurodegenerative diseases is complex and diverse, usually involving oxidative stress, mitochondrial dysfunction, metal homeostasis disorder, and neuro-inflammation. The precise molecular mechanisms underlying neurodegeneration remain unclear, which is a major obstacle to therapeutic approaches. Therefore, it is urgent to improve the understanding of the molecular mechanisms of neurodegenerative processes and to identify the therapeutic targets for treatment and prevention. Ferroptosis is a regulatory cell necrosis caused by iron ion catalysis and lipid peroxidation induced by reactive oxygen species (ROS), which is thought to be associated with nervous system diseases, particularly neurodegenerative diseases. This review overviewed the ferroptosis process and explored the relationship of ferroptosis with substance abuse and neurodegenerative diseases, which provides a new way to study the molecular mechanisms of neurodegenerative diseases induced by alcohol, cocaine, and methamphetamine (MA), and also provides the potential therapeutic targets for substance abuse-induced neurodegenerative diseases.

Cellular Bioenergetics: Experimental Evidence for Alcohol-induced Adaptations

At-risk alcohol use is associated with multisystemic effects and end-organ injury, and significantly contributes to global health burden. Several alcohol-mediated mechanisms have been identified, with bioenergetic maladaptation gaining credence as an underlying pathophysiological mechanism contributing to cellular injury. This evidence-based review focuses on the current knowledge of alcohol-induced bioenergetic adaptations in metabolically active tissues: liver, cardiac and skeletal muscle, pancreas, and brain. Alcohol metabolism itself significantly interferes with bioenergetic pathways in tissues, particularly the liver. Alcohol decreases states of respiration in the electron transport chain, and activity and expression of respiratory complexes, with a net effect to decrease ATP content. In addition, alcohol dysregulates major metabolic pathways, including glycolysis, the tricarboxylic acid cycle, and fatty acid oxidation. These bioenergetic alterations are influenced by alcohol-mediated changes in mitochondrial morphology, biogenesis, and dynamics. The review highlights similarities and differences in bioenergetic adaptations according to tissue type, pattern of (acute vs. chronic) alcohol use, and energy substrate availability. The compromised bioenergetics synergizes with other critical pathophysiological mechanisms, including increased oxidative stress and accelerates cellular dysfunction, promoting senescence, programmed cell death, and end-organ injury.

Exosome mediated Tom40 delivery protects against hydrogen peroxide-induced oxidative stress by regulating mitochondrial function

Mitochondrial dysfunction is a hallmark of neurodegeneration. The expression level of Tom40, a crucial mitochondrial membrane protein, is significantly reduced in neurodegenerative disease subjects. Tom40 overexpression studies have shown to protect the neurons against oxidative stress by improving mitochondrial function. Thus, successful delivery of Tom40 protein to the brain could lead to a novel therapy for neurodegenerative diseases. However, delivering protein to the cell may be difficult. Especially the blood-brain barrier (BBB) is a big hurdle to clear in order to deliver the protein to the brain. In the current study, we engineered exosomes, which are the extracellular vesicles of endosomal origin, and able to cross BBB as delivery vehicles packing human Tom40. We found Tom40 protein delivery by the exosome successfully protected the cells against hydrogen peroxide-induced oxidative stress. This result suggests that exosome-mediated delivery of Tom40 may potentially be useful in restoring mitochondrial functions and alleviating oxidative stress in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases.

Chronic Alcohol Exposure Alters Gene Expression and Neurodegeneration Pathways in the Brain of Adult Mice

BACKGROUND

Chronic alcohol consumption can alter the structure of the central nervous system and disrupt cognitive function. Alcoholics are more likely to develop neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). However, the role of alcohol in promoting neurotoxicity and neurodegeneration remains unclear.

OBJECTIVE

In this study, we aimed at estimating the effects of chronic binge alcohol exposure on brain transcriptome and behavior changes in a chronic "Drinking in the Dark" (DID) mouse model.

METHODS

The adult C57BL/6J male mice were exposed to alcohol for 4 weeks. RNA-seq was applied to assess the effects of chronic alcohol exposure on transcriptome in brain. The open field test and novel object recognition test were used to assess the changes of anxiety level, locomotive function, and short-term memory induced by alcohol. RNA-seq analysis revealed that chronic alcohol exposure caused significant change in the brain transcriptome, especially in prefrontal cortex.

RESULTS

The gene dysregulation caused by chronic alcohol exposure includes pathways related to mitochondrial energy metabolism (such as oxidative phosphorylation) and multiple neurodegenerative diseases (such as AD and PD). Furthermore, the pathway and network analyses suggest that the genes involved in mitochondrial energy metabolism, ubiquitin-proteasome system, Wnt signaling pathway, and microtubules may attribute to the neurotoxicity and neurodegeneration caused by chronic alcohol consumption. Additionally, locomotive function was also significantly impaired.

CONCLUSION

This work provides gene transcriptional profile data for future research on alcohol-induced neurodegenerative diseases, especially AD and PD.

Alcohol hangover induces nitric oxide metabolism changes by impairing NMDA receptor-PSD95-nNOS pathway

Alcohol hangover is defined as the combination of mental and physical symptoms experienced the day after a single episode of heavy drinking, starting when blood alcohol concentration approaches zero. We previously evidenced increments in free radical generation and an imbalance in antioxidant defences in non-synaptic mitochondria and synaptosomes during hangover. It is widely known that acute alcohol exposure induces changes in nitric oxide (NO) production and blocks the binding of glutamate to NMDAR in central nervous system. Our aim was to evaluate the residual effect of acute ethanol exposure (hangover) on NO metabolism and the role of NMDA receptor-PSD95-nNOS pathway in non-synaptic mitochondria and synaptosomes from mouse brain cortex. Results obtained for the synaptosomes fraction showed a 37% decrease in NO total content, a 36% decrease in NOS activity and a 19% decrease in nNOS protein expression. The in vitro addition of glutamate to synaptosomes produced a concentration-dependent enhancement of NO production which was significantly lower in samples from hangover mice than in controls for all the glutamate concentrations tested. A similar patter of response was observed for nNOS activity being decreased both in basal conditions and after glutamate addition. In addition, synaptosomes exhibited a 64% and 15% reduction in NMDA receptor subunit GluN2B and PSD-95 protein expression, respectively. Together with this, glutamate-induced calcium entry was significant decreased in synaptosomes from alcohol-treated mice. On the other hand, in non-synaptic mitochondria, no significant differences were observed in NO content, NOS activity or nNOS protein expression. The expression of iNOS remained unaltered in synaptosomes and non-synaptic mitochondria. Here we demonstrated that hangover effects on NO metabolism are strongly evidenced in synaptosomes probably due to a disruption in NMDAR/PSD-95/nNOS pathway.

Biphasic Effects of Ethanol Exposure on Waste Metabolites Clearance in the CNS

We have shown that the effects of low-dose ethanol promote the clearance of waste metabolites, such as amyloid-beta (Aβ) proteins, from the brain through the perivascular space (PVS). We demonstrated that dilative reactivity of arterial smooth muscle and endothelial cells regulate this clearance. These findings indicate the importance of blood-brain barrier (BBB) transvascular clearance of large size metabolites from the central nervous system (CNS), where the lymphatic clearance system is absent. We next examined the contrasting effects of acute low-dose and chronic moderate ethanol exposure on BBB-associated perivascular clearance. We injected a high molecular weight fluorescent dye into the interstitial space or directly into the cerebrospinal fluid (CSF). Bio-distribution of this tracer was then examined in different brain regions by multiphoton imaging and whole brain tissue section scanning. Ethanol-induced molecular/cellular mechanisms that drive the increase or decrease in movement of the fluorescent tracer were correlated to BBB integrity and arterial vessel reactivity. We found that activation of endothelial nitric oxide synthase (eNOS) under low-dose ethanol conditions with a shift to activation of inducible NOS (iNOS) under chronic high ethanol exposure conditions, which appeared to regulate these contrasting effects. We validated these observations by qualitative and quantitative investigation of eNOS, iNOS, BBB integrity, and perivascular clearance of waste metabolites. We concluded that the effects of low-dose ethanol increased the diffusive movement of waste metabolites via eNOS-derived NO, which increased the arterial endothelial-smooth muscle cell dilative reactivity without affecting BBB integrity, whereas a prolonged induction of iNOS under chronic ethanol exposure conditions caused oxidative damage of the arterial endothelial-smooth muscle layers resulting in cerebral amyloid-like angiopathy. This led to dysfunction of the BBB, dilative reactivity, and impaired waste metabolites movement from the interstitial space or subarachnoid space (SAS) through perivascular clearance.

Carnitine in Alcohol Use Disorders: A Scoping Review

Recent studies in alcohol use disorders (AUDs) have demonstrated some connections between carnitine metabolism and the pathophysiology of the disease. In this scoping review, we aimed to collate and examine existing research available on carnitine metabolism and AUDs and develop hypotheses surrounding the role carnitine may play in AUD. A scoping review method was used to search electronic databases in September 2019. The database search terms used included “alcohol, alcoholism, alcohol abuse, alcohol consumption, alcohol drinking patterns, alcohol‐induced disorders, alcoholic intoxication, alcohol‐related disorders, binge drinking, Wernicke encephalopathy, acylcarnitine, acetyl‐l‐carnitine, acetylcarnitine, carnitine and palmitoylcarnitine.” The inclusion criteria included English language, human‐based, AUD diagnosis and measured blood or tissue carnitine or used carnitine as a treatment. Of 586 studies that were identified and screened, 65 underwent abstract review, and 41 were fully reviewed. Eighteen studies were ultimately included for analysis. Data were summarized in an electronic data extraction form. We found that there is limited literature available. Alcohol use appears to impact carnitine metabolism, most clearly in the setting of alcoholic cirrhosis. Six studies found carnitine to be increased in AUD, of which 5 were conducted in patients with alcoholic cirrhosis. Only 3 placebo‐controlled trials were identified and provide some support for the use of carnitine in AUD to decrease cravings, anhedonia, and withdrawal and improve cognition. The increase in plasma carnitine in alcoholic cirrhosis may be related to disordered fatty acid metabolism and oxidative stress that occurs in AUD. The multiple possible therapeutic effects carnitine could have on ethanol metabolism and the early evidence available for carnitine supplementation as a treatment for AUD provide a foundation for future randomized control trials of carnitine for treating AUD.

Assessment of Ethanol-Induced Toxicity on iPSC-Derived Human Neurons Using a Novel High-Throughput Mitochondrial Neuronal Health (MNH) Assay

Excessive ethanol exposure can cause mitochondrial and cellular toxicity. In order to discover potential counteracting interventions, it is essential to develop assays capable of capturing the consequences of ethanol exposure in human neurons, and particularly dopaminergic neurons that are crucial for the development of alcohol use disorders (AUD). Here, we developed a novel high-throughput (HT) assay to quantify mitochondrial and neuronal toxicity in human dopaminergic neuron-containing cultures (DNs) from induced pluripotent stem cells (iPSCs). The assay, dubbed mitochondrial neuronal health (MNH) assay, combines live-cell measurement of mitochondrial membrane potential (MMP) with quantification of neuronal branching complexity post-fixation. Using the MNH assay, we demonstrated that chronic ethanol exposure in human iPSC-derived DNs decreases MMP and neuronal outgrowth in a dose-dependent manner. The toxic effect of ethanol on DNs was already detectable after 1 h of exposure, and occurred similarly in DNs derived from healthy individuals and from patients with AUD. We next used the MNH assay to carry out a proof-of-concept compound screening using FDA-approved drugs. We identified potential candidate compounds modulating acute ethanol toxicity in human DNs. We found that disulfiram and baclofen, which are used for AUD treatment, and lithium caused neurotoxicity also in the absence of ethanol, while the spasmolytic drug flavoxate positively influenced MNH. Altogether, we developed an HT assay to probe human MNH and used it to assess ethanol neurotoxicity and to identify modulating agents. The MNH assay represents an effective new tool for discovering modulators of MNH and toxicity in live human neurons.

Potential Role of Extracellular CIRP in Alcohol-Induced Alzheimer's Disease

Alzheimer's disease (AD) is the sixth leading cause of death in the USA and the most common form of neurodegenerative dementia. In AD, microtubule-associated protein tau becomes pathologically phosphorylated and aggregated, leading to neurodegeneration and the cognitive deficits that characterize the disease. Prospective studies have shown that frequent and heavy alcohol drinking is linked to early onset and increased severity of AD. The precise mechanisms of how alcohol leads to AD, however, remain poorly understood. We have shown that extracellular cold-inducible RNA-binding protein (eCIRP) is a critical mediator of memory impairment induced by exposure to binge-drinking levels of alcohol, leading us to reason that eCIRP may be a key player in the relationship between alcohol and AD. In this review, we first discuss the mechanisms by which alcohol promotes AD. We then review eCIRP's role as a critical mediator of acute alcohol intoxication-induced neuroinflammation and cognitive impairment. Next, we explore the potential contribution of eCIRP to the development of alcohol-induced AD by targeting tau phosphorylation. We also consider the effects of eCIRP on neuronal death and neurogenesis linking alcohol with AD. Finally, we highlight the importance of further studying eCIRP as a critical molecular mechanism connecting acute alcohol intoxication, neuroinflammation, and tau phosphorylation in AD along with the potential of therapeutically targeting eCIRP as a new strategy to attenuate alcohol-induced AD.

Alcohol induces programmed death receptor-1 and programmed death-ligand-1 differentially in neuroimmune cells

Engagement of programmed death-1 (PD-1) receptor by its ligands (PD-L1/PD-L2) in activated immune cells is known to be involved in inflammatory neurological disease via a co-inhibitory signal pathway. Interaction of PD-1/PD-L1 is believed to occur only in activated neuroimmune cells because there are undetectable levels of PD-1/PD-L1 in normal physiological conditions. Here, we evaluated whether activation of neuroimmune cells such as human macrophage, brain endothelial cells (hBECs), astrocytes, microglia, and neurons by non-toxic concentrations of ethanol (EtOH) exposure can alter PD-1/PD-L1 expression. Thus, the present study is limited to the screening of PD-1/PD-L1 alterations in neuroimmune cells following ethanol exposure. We found that exposure of human macrophage or microglia to EtOH in primary culture immediately increased the levels of PD-L1 and gradually up-regulated PD-1 levels (beginning at 1-2 h). Similarly, ethanol exposure was able to induce PD-1/PD-L1 levels in hBECs and neuronal culture in a delayed process (occurring at 24 h). Astrocyte culture was the only cell type that showed endogenous levels of PD-1/PD-L1 that was decreased by EtOH exposure time-dependently. We concluded that ethanol (alcohol) mediated the induction of PD-1/PD-L1 differentially in neuroimmune cells. Taken together, our findings suggest that up-regulation of PD-1/PD-L1 by chronic alcohol use may dampen the innate immune response of neuroimmune cells, thereby contributing to neuroinflammation and neurodegeneration.

Low-Level Saturated Fatty Acid Palmitate Benefits Liver Cells by Boosting Mitochondrial Metabolism via CDK1-SIRT3-CPT2 Cascade

Saturated fatty acids (SFAs) (the "bad" fat), especially palmitate (PA), in the human diet are blamed for potential health risks such as obesity and cancer because of SFA-induced lipotoxicity. However, epidemiological results demonstrate a latent benefit of SFAs, and it remains elusive whether a certain low level of SFAs is physiologically essential for maintaining cell metabolic hemostasis. Here, we demonstrate that although high-level PA (HPA) indeed induces lipotoxic effects in liver cells, low-level PA (LPA) increases mitochondrial functions and alleviates the injuries induced by HPA or hepatoxic agent carbon tetrachloride (CCl₄). LPA treatment in mice enhanced liver mitochondrial activity and reduced CCl₄ hepatotoxicity with improved blood levels of aspartate aminotransferase (AST), alanine transaminase (ALT), and mitochondrial aspartate transaminase (m-AST). LPA-mediated mitochondrial homeostasis is regulated by CDK1-mediated SIRT3 phosphorylation, which in turn deacetylates and dimerizes CPT2 to enhance fatty acid oxidation. Thus, an advantageous effect is suggested by the consumption of LPA that augments mitochondrial metabolic homeostasis via CDK1-SIRT3-CPT2 cascade.

Alcohol impairs hippocampal function: From NMDA receptor synaptic transmission to mitochondrial function

Many studies have reported that alcohol produces harmful effects on several brain structures, including the hippocampus, in both rodents and humans. The hippocampus is one of the most studied areas of the brain due to its function in learning and memory, and a lot of evidence suggests that hippocampal failure is responsible for the cognitive loss present in individuals with recurrent alcohol consumption. Mitochondria are organelles that generate the energy needed for the brain to maintain neuronal communication, and their functional failure is considered a mediator of the synaptic dysfunction induced by alcohol. In this review, we discuss the mechanisms of how alcohol exposure affects neuronal communication through the impairment of glutamate receptor (NMDAR) activity, neuroinflammatory events and oxidative damage observed after alcohol exposure, all processes under the umbrella of mitochondrial function. Finally, we discuss the direct role of mitochondrial dysfunction mediating cognitive and memory decline produced by alcohol exposure and their consequences associated with neurodegeneration.

Neurochemical mechanisms underlying acute and chronic ethanol-mediated responses in zebrafish: The role of mitochondrial bioenergetics

Ethanol (EtOH) is a socially-accepted drug, whose consumption is a risk factor for non-intentional injuries, development of pathologies, and addiction. In the brain, EtOH affects redox signaling and increases reactive oxygen species (ROS) production after acute and chronic exposures. Here, using a high-resolution respirometry assay, we investigated whether changes in mitochondrial bioenergetics play a role in both acute and chronic EtOH-mediated neurochemical responses in zebrafish. For the first time, we showed that acute and chronic EtOH exposures differently affect brain mitochondrial function. Acutely, EtOH stimulated mitochondrial respiration through increased baseline state, CI-mediated OXPHOS, OXPHOS capacity, OXPHOS coupling efficiency, bioenergetic efficiency, and ROX/ETS ratio. Conversely, EtOH chronically decreased baseline respiration, complex I- and II-mediated ETS, as well as increased ROX state and ROX/ETS ratio, which are associated with ROS formation. Overall, we observed that changes in mitochondrial bioenergetics play a role, at least partially, in both acute and chronic effects of EtOH in the zebrafish brain. Moreover, our findings reinforce the face, predictive, and construct validities of zebrafish models to explore the neurochemical bases involved in alcohol abuse and alcoholism.

Chronic Ethanol Exposure Disrupts Lactate and Glucose Homeostasis and Induces Dysfunction of the Astrocyte-Neuron Lactate Shuttle in the Brain

BACKGROUND

Impairment of monocarboxylate transporter (MCT)-dependent astrocyte-neuron lactate transfer disrupts long-term memory and erases drug-associated memories in mice. However, few studies have examined how drugs of abuse alter astrocyte-neuron lactate transfer in neurocircuits related to addiction. This is particularly pertinent for ethanol (EtOH), which has been demonstrated to impair central nervious system (CNS) glucose uptake and significantly alter peripheral levels of glucose, lactate, acetate, and ketones.

METHODS

We subjected C57BL/6J mice to a chronic intermittent EtOH (CIE) exposure paradigm to investigate how chronic EtOH exposure alters the concentration of glucose and lactate within the serum and CNS during withdrawal. Next, we determine how chronic injections of lactate (1 g/kg, twice daily for 2 weeks) influence central and peripheral glucose and lactate concentrations. Finally, we determine how CIE and chronic lactate injection affect astrocyte-neuron lactate transfer by analyzing the expression of MCTs.

RESULTS

Our results show that CIE induces lasting changes in CNS glucose and lactate concentrations, accompanied by increased expression of MCTs. Interestingly, although chronic lactate injection mimics the effect of EtOH on CNS metabolites, chronic lactate injection is not associated with increased expression of MCTs.

CONCLUSION

CIE increases CNS concentrations of glucose and lactate and augments the expression of MCTs. Although we found that chronic lactate injection mimics EtOH-induced increases in CNS lactate and glucose, lactate failed to alter the expression of MCTs. This suggests that although lactate may influence the homeostasis of bioenergetic molecules in the CNS, EtOH-associated increases in lactate are not responsible for increased MCT expression.

Alcohol hangover effects on brain cortex non-synaptic mitochondria and synaptosomes bioenergetics

Alcohol hangover (AH) has been associated with oxidative stress and mitochondrial dysfunction. We herein postulate that AH-induced mitochondrial alterations can be due to a different pattern of response in synaptosomes and non-synaptic (NS) mitochondria. Mice received intraperitoneal (i.p.) injections of ethanol (3.8 g/kg) or saline and were sacrificed 6 h afterward. Brain cortex NS mitochondria and synaptosomes were isolated by Ficoll gradient. Oxygen consumption rates were measured in NS mitochondria and synaptosomes by high-resolution respirometry. Results showed that NS-synaptic mitochondria from AH animals presented a 26% decrease in malate-glutamate state 3 respiration, a 64% reduction in ATP content, 28-37% decrements in ATP production rates (malate-glutamate or succinate-dependent, respectively), and 44% inhibition in complex IV activity. No changes were observed in mitochondrial transmembrane potential (ΔΨ) or in UCP-2 expression in NS-mitochondria. Synaptosome respiration driving proton leak (in the presence of oligomycin), and spare respiratory capacity (percentage ratio between maximum and basal respiration) were 30% and 15% increased in hangover condition, respectively. Synaptosomal ATP content was 26% decreased, and ATP production rates were 40-55% decreased (malate-glutamate or succinate-dependent, respectively) in AH mice. In addition, a 24% decrease in ΔΨ and a 21% increase in UCP-2 protein expression were observed in synaptosomes from AH mice. Moreover, mitochondrial respiratory complexes I-III, II-III, and IV activities measured in synaptosomes from AH mice were decreased by 18%, 34%, and 50%, respectively. Results of this study reveal that alterations in bioenergetics status during AH could be mainly due to changes in mitochondrial function at the level of synapses.

Ethanol exposed maturing rat cerebellar granule cells show impaired energy metabolism and increased cell death after oxygen-glucose deprivation

Alcohol, a widely abused drug, has deleterious effects on the immature nervous system. This study investigates the effect of chronic in vitro ethanol exposure on the metabolism of immature rat cerebellar granular cells (CGCs) and on their response to oxygen-glucose deprivation (OGD). Primary CGC cultures were exposed to ethanol (100 mM in culture medium) or to control ethanol-free medium starting day one in vitro (DIV1). At DIV8, the expression of ATP synthase gene ATP5g3 was quantified using real-time PCR, then cultures were exposed to 3 hours of OGD or normoxic conditions. Subsequently, cellular metabolism was assessed by a resazurin assay and by ATP level measurement. ATP5g3 expression was reduced by 12-fold (P = 0.03) and resazurin metabolism and ATP level were decreased to 74.4 ± 4.6% and 55.5 ± 6.9%, respectively after chronic ethanol treatment compared to control values (P < 0.01). Additionally, after OGD exposure of ethanol-treated cultures, resazurin metabolism and ATP level were decreased to 12.7 ± 1.0% and 9.0 ± 2.0% from control values (P < 0.01). These results suggest that chronic ethanol exposure reduces the cellular ATP level, possibly through a gene expression down-regulation mechanism, and increases the vulnerability to oxygen-glucose deprivation. Thus, interventions which improve metabolic function and sustain ATP-levels could attenuate ethanol-induced neuronal dysfunction and should be addressed in future studies.

Thyroid Hormone Stimulation of Adult Brain Fatty Acid Oxidation

Thyroid hormone is a critical modulator of brain metabolism, and it is highly controlled in the central nervous system. Recent research has uncovered an important role of thyroid hormone in the regulation of fatty acid oxidation (FAO), an energetic process essential for neurodevelopment that continues to support brain metabolism during adulthood. Thyroid hormone stimulation of FAO has been shown to be protective in astrocytes and mouse models of brain injury, yet a clear mechanism of this relationship has not been elucidated. Thyroid hormone interacts with multiple receptors located in the nucleus and the mitochondria, initiating rapid and long-term effects via both genomic and nongenomic pathways. This has complicated efforts to isolate and study-specific interactions. This chapter presents the primary signaling pathways that have been identified to play a role in the thyroid hormone-mediated increase in FAO. Investigation of the impact of thyroid hormone on FAO in the adult brain has challenged classical models of brain metabolism and widened the window of potential neuroprotective strategies. A detailed understanding of these pathways is essential for any researchers aiming to expand the field of neuroenergetics.

LC-MS-based urinary metabolite signatures in idiopathic Parkinson's disease

Increasing evidence has shown that abnormal metabolic phenotypes in body fluids reflect the pathogenesis and pathophysiology of Parkinson's disease (PD). These body fluids include urine; however, the relationship between, specifically, urinary metabolic phenotypes and PD is not fully understood. In this study, urinary metabolites from a total of 401 clinical urine samples collected from 106 idiopathic PD patients and 104 normal control subjects were profiled by using high-performance liquid chromatography coupled to high-resolution mass spectrometry. Our study revealed significant correlation between clinical phenotype and urinary metabolite profile. Metabolic profiles of idiopathic PD patients differed significantly and consistently from normal controls, with related metabolic pathway variations observed in steroidogenesis, fatty acid beta-oxidation, histidine metabolism, phenylalanine metabolism, tryptophan metabolism, nucleotide metabolism, and tyrosine metabolism. In the fruit fly Drosophila melanogaster, the alteration of the kynurenine pathway in tryptophan metabolism corresponded with pathogenic changes in the alpha-synuclein overexpressed Drosophila model of PD. The results suggest that LC-MS-based urinary metabolomic profiling can reveal the metabolite signatures and related variations in metabolic pathways that characterize PD. Consistent PD-related changes across species may provide the basis for understanding metabolic regulation of PD at the molecular level.

Analysis of alcoholic EEG signals based on horizontal visibility graph entropy

This paper proposes a novel horizontal visibility graph entropy (HVGE) approach to evaluate EEG signals from alcoholic subjects and controlled drinkers and compare with a sample entropy (SaE) method. Firstly, HVGEs and SaEs are extracted from 1,200 recordings of biomedical signals, respectively. A statistical analysis method is employed to choose the optimal channels to identify the abnormalities in alcoholics. Five group channels are selected and forwarded to a K-Nearest Neighbour (K-NN) and a support vector machine (SVM) to conduct classification, respectively. The experimental results show that the HVGEs associated with left hemisphere, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C$$\end{document}C1, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C$$\end{document}C3 and FC5 electrodes, of alcoholics are significantly abnormal. The accuracy of classification with 10-fold cross-validation is 87.5 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}% with about three HVGE features. By using just optimal 13-dimension HVGE features, the accuracy is 95.8 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}%. In contrast, SaE features associated cannot identify the left hemisphere disorder for alcoholism and the maximum classification ratio based on SaE is just 95.2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}% even using all channel signals. These results demonstrate that the HVGE method is a promising approach for alcoholism identification by EEG signals.