Gender differences in the inflammatory cytokine and chemokine profiles induced by binge ethanol drinking in adolescence

The emerging role of mesenchymal stem cell-derived extracellular vesicles to ameliorate hippocampal NLRP3 inflammation induced by binge-like ethanol treatment in adolescence

JOURNAL/nrgr/04.03/01300535-202504000-00030/figure1/v/2024-07-06T104127Z/r/image-tiff Our previous studies have reported that activation of the NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3)-inflammasome complex in ethanol-treated astrocytes and chronic alcohol-fed mice could be associated with neuroinflammation and brain damage. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been shown to restore the neuroinflammatory response, along with myelin and synaptic structural alterations in the prefrontal cortex, and alleviate cognitive and memory dysfunctions induced by binge-like ethanol treatment in adolescent mice. Considering the therapeutic role of the molecules contained in mesenchymal stem cell-derived extracellular vesicles, the present study analyzed whether the administration of mesenchymal stem cell-derived extracellular vesicles isolated from adipose tissue, which inhibited the activation of the NLRP3 inflammasome, was capable of reducing hippocampal neuroinflammation in adolescent mice treated with binge drinking. We demonstrated that the administration of mesenchymal stem cell-derived extracellular vesicles ameliorated the activation of the hippocampal NLRP3 inflammasome complex and other NLRs inflammasomes (e.g., pyrin domain-containing 1, caspase recruitment domain-containing 4, and absent in melanoma 2, as well as the alterations in inflammatory genes (interleukin-1β, interleukin-18, inducible nitric oxide synthase, nuclear factor-kappa B, monocyte chemoattractant protein-1, and C-X3-C motif chemokine ligand 1) and miRNAs (miR-21a-5p, miR-146a-5p, and miR-141-5p) induced by binge-like ethanol treatment in adolescent mice. Bioinformatic analysis further revealed the involvement of miR-21a-5p and miR-146a-5p with inflammatory target genes and NOD-like receptor signaling pathways. Taken together, these findings provide novel evidence of the therapeutic potential of MSC-derived EVs to ameliorate the hippocampal neuroinflammatory response associated with NLRP3 inflammasome activation induced by binge drinking in adolescence.

Unraveling the Impact of TLR4 and Sex on Chronic Alcohol Consumption-Induced Lipidome Dysregulation in Extracellular Vesicles

The lipids that form extracellular vesicles (EVs) play critical structural and regulatory roles, and cutting-edge bioinformatics strategies have shown the ability to decipher lipid metabolism and related molecular mechanisms. We previously demonstrated that alcohol abuse induces an inflammatory immune response through Toll-like receptor 4 (TLR4), leading to structural and cognitive dysfunction. This study evaluated how TLR4 and sex as variables (male/female) impact the lipidome of plasma-resident EVs after chronic alcohol exposure. Using a mouse model of chronic ethanol exposure in wild-type and TLR4-deficient mice, enrichment networks generated by LINEX2 highlighted significant ethanol-induced changes in the EV lipid substrate-product of enzyme reactions associated with glycerophospholipid metabolism. We also demonstrated ethanol-induced differences in Lipid Ontology enrichment analysis in EVs, focusing on terms related to lipid bilayer properties. A lipid abundance analysis revealed higher amounts of significant lipid subclasses in all experimental comparisons associated with inflammatory responses and EV biogenesis/secretion. These findings suggest that interrogating EV lipid abundance with a sensitive lipidomic-based strategy can provide deep insight into the molecular mechanisms underlying biological processes associated with sex, alcohol consumption, and TLR4 immune responses and open new avenues for biomarker identification and therapeutic development.

Alcohol drinking is attenuated by PDE4 inhibition but partial microglia depletion is not sufficient to block stress-induced escalation of alcohol intake in female mice

Stress is a major contributing factor to binge drinking and development of alcohol use disorders (AUD), particularly in women. Both stress and chronic ethanol can enhance neuroinflammatory processes, which may dysregulate limbic circuits involved in ethanol reinforcement. Clinical and preclinical studies have identified sex differences in alcohol intake in response to neuroinflammatory triggers. Since both cyclic AMP (cAMP) signaling and microglial activation contribute to neuroinflammation, we explored their contribution to stress-induced ethanol drinking in mice. To this end, we first trained C57BL/6J male and female mice to volitionally drink ethanol through a modified version of the "Drinking-in-the-Dark" paradigm. We then assessed whether exposure to foot shock stress followed by repeated exposure to the previously stress-paired context might alter volitional ethanol drinking. We observed that stress exposure resulted in a delayed increase in ethanol intake, but only in female mice. The anti-inflammatory drug Apremilast, an inhibitor of phosphodiesterase type 4 (PDE4; the primary enzyme for cAMP degradation in the brain), reduced ethanol intake and decreased preference for ethanol regardless of stress exposure in females. In contrast, a partial pharmacological depletion of microglia via PLX3397 treatment did not significantly alter baseline ethanol drinking or stress-induced ethanol drinking in female mice. This study shows that female mice are more susceptible to stress-induced ethanol drinking than males, and that this occurs even after partial microglial depletion. In addition, modulation of cAMP signaling by Apremilast administration reduced ethanol drinking regardless of stress exposure, supporting the idea that it might be useful for treatment of AUD.

Metagenomics Reveals Sex-Based Differences in Murine Fecal Microbiota Profiles Induced by Chronic Alcohol Consumption

Chronic ethanol exposure induces an inflammatory response within the intestinal tract, compromising mucosal and epithelial integrity and leading to dysbiosis of the gut microbiome. However, the specific roles of the gut microbiota in mediating ethanol-induced effects, as well as their interactions with the immune system, remain poorly characterized. This study aimed to evaluate sex-based differences in fecal microbiota profiles induced by chronic alcohol consumption and to assess whether TLR4 is involved in these effects. We analyzed the 16S rRNA gene sequencing of fecal samples from male and female wild-type (WT) and TLR4-knockout (TLR4-KO) mice with and without chronic ethanol exposure over a three-month period. Our findings provide evidence, for the first time, that male mice are more susceptible to the effects of ethanol on the fecal microbiota, since ethanol exposure induced greater alterations in the Gram-negative and -positive bacteria with immunogenic capacity in the WT male mice than in the female mice. We also demonstrate that the absence of immune receptor TLR4 leads to different microbiota in both sexes, showing anti-inflammatory and protective properties for intestinal barrier function and resulting in a phenotype more resistant to ethanol's effects. These findings may open new avenues for understanding the relationship between gut microbiota profiles and inflammation in the digestive system induced by chronic alcohol consumption.

Alcohol-Induced Activation of Chemokine System and Neuroinflammation Development

Chemokines are immunoregulatory proteins with pleiotropic functions involved in neuromodulation, neurogenesis, and neurotransmission. The way chemokines affect the CNS plays an important role in modulating various conditions that could have negative impact on CNS functions, including development of alcohol use disorders. In this review, we analyzed the literature data available on the problem of chemokine participation in pathogenesis, clinical presentation, and remission of alcohol use disorders both in animal models and in the study of patients with alcoholism. The presented information confirms the hypothesis that the alcohol-induced chemokine production could modulate chronic neuroinflammation. Thus, the data summarized and shown in this review are focused on the relevant direction of research in the field of psychiatry, which is in demand by both scientists and clinical specialists.

Ethanol drinking sex-dependently alters cortical IL-1β synaptic signaling and cognitive behavior in mice

Individuals with alcohol use disorder (AUD) struggle with inhibitory control, decision making, and emotional processing. These cognitive symptoms reduce treatment adherence, worsen clinical outcomes, and promote relapse. Neuroimmune activation is a key factor in the pathophysiology of AUD, and targeting this modulatory system is less likely to produce unwanted side effects compared to directly targeting neurotransmitter dysfunction. Notably, the cytokine interleukin-1β (IL-1β) has been broadly associated with the cognitive symptoms of AUD, though the underlying mechanisms are not well understood. Here we investigated how chronic intermittent 24-hour access two bottle choice ethanol drinking affects medial prefrontal cortex (mPFC)-related cognitive function and IL-1 synaptic signaling in male and female C57BL/6J mice. In both sexes, ethanol drinking decreased reference memory and increased mPFC IL-1 receptor 1 (IL-1R1) mRNA levels. In neurons, IL-1β can activate either pro-inflammatory or neuroprotective intracellular pathways depending on the isoform of the accessory protein (IL-1RAcP) recruited to the IL-1R1 complex. Moreover, ethanol drinking sex-dependently shifted mPFC IL-1RAcP isoform gene expression and IL-1β regulation of mPFC GABA synapses, both of which may contribute to female mPFC resiliency and male mPFC susceptibility. This type of signaling bias has become a recent focus of rational drug development. Therefore, in addition to increasing our understanding of how IL-1β sex-dependently contributes to mPFC dysfunction in AUD, our current findings also support the development of a new class of pharmacotherapeutics based on biased IL-1 signaling.

Unveiling causal relationships between addiction phenotypes and inflammatory cytokines: insights from bidirectional mendelian randomization and bibliometric analysis

Observational studies have suggested associations between multiple inflammatory factors and tobacco and alcohol use, but establishing causation is challenging in epidemiological investigations. We employed genetic association data about the circulating levels of 41 cytokines obtained from the genome-wide association study (GWAS), which contained 8293 Finnish participants. Genetic data on 5 substance use phenotypes were obtained from the GWAS dataset containing 1.2 million European subjects. Then, we conducted a bidirectional mendelian randomization (MR) study. The forward results indicated that smoking cessation was positively correlated with hepatocyte growth factor (HGF), interleukin-10 (IL-10), and stem cell factor (SCF); cigarettes per day was a risk factor associated with high expression in stromal cell-derived factor 1α (SDF-1 A), interferon-γ (IFN-G), IL-4, and granulocyte colony-stimulating factor (G-CSF); drinks per week and smoking initiation were risk factors respectively correlated with reduced HGF and IL-2RA levels. During inverse MR analysis, the findings revealed that both IL-16 and IL-18 increased the risk of cigarettes per day; macrophage inflammatory protein-1β (MIP-1B) and tumor necrosis factor-β (TNF-B) inhibited and promoted smoking cessation, respectively; macrophage colony-stimulating factor (M-CSF) elevated the risk of drinks per week, while interferon inducible protein 10 (IP-10) had a contrary role; IL-7 and M-CSF respectively prolonged and shortened age of initiation of regular smoking. This study provides genetic proof supporting a causal relationship between various inflammatory factors and addiction phenotypes. Further comprehensive investigations are required to uncover underlying biological mechanisms. In addition, bibliometric studies have shown that oxidative stress is one of the most important orientations in alcohol and tobacco addiction research, where an in-depth investigation of its pro-inflammatory mechanisms would facilitate the development of potential therapeutic biological targets and drugs.

Cannabidiol or ketamine for preventing the impact of adolescent early drug initiation on voluntary ethanol consumption in adulthood

Background

Few studies have previously evaluated the long-term impact of initiating the combined use of alcohol and cocaine early-in-life during adolescence. Our preclinical study characterized changes in affective-like behavior and/or voluntary ethanol consumption emerging later on in adulthood induced by a prior adolescent drug exposure, as well as tested therapeutical interventions (i.e., cannabidiol or ketamine) to prevent the observed effects.

Methods

We performed three independent studies with male and female Sprague-Dawley rats, treated in adolescence (postnatal days, PND 29-38) with non-contingent paradigms of ethanol, cocaine, their combination or vehicle. Later on, adult rats were (1) scored for their affective-like state (forced-swim, elevated-plus maze, novelty-suppressed feeding, sucrose preference), (2) allowed to freely drink ethanol for 6 weeks (two-bottle choice), or (3) treated with cannabidiol or ketamine before given access to ethanol in adulthood.

Results

No signs of increased negative affect were observed in adulthood following the adolescent treatments. However, adolescent ethanol exposure was a risk-factor for later developing an increased voluntary ethanol consumption in adulthood, both for male and female rats. This risk was similar when ethanol was combined with adolescent cocaine exposure, since cocaine alone showed no effects on later ethanol intake. Finally, rats exposed to adolescent ethanol and pretreated in adulthood with cannabidiol (and/or ketamine, but just for females) reduced their ethanol voluntary consumption.

Conclusion

Our data provided two therapeutical options capable of preventing the impact of an early drug initiation during adolescence by decreasing voluntary ethanol consumption in adult rats.

Sex-specific effects of alcohol on neurobehavioral performance and endoplasmic reticulum stress: an analysis using neuron-specific MANF deficient mice

Excessive alcohol exposure can cause neurobehavioral deficits and structural alterations in the brain. Emerging research evidence suggests that endoplasmic reticulum (ER) stress plays an important role in alcohol-induced neurotoxicity. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an ER stress inducible protein and is responsible to maintain ER homeostasis. MANF is highly expressed in both the developing and mature brain. We have previously shown that MANF deficiency exacerbated alcohol induced neurodegeneration and ER stress in the developing brain. However, little is known regarding the role of MANF in alcohol induced neuronal damage in the adult brain. In this study, we used a neuron-specific MANF knockout (KO) mouse model to investigate the effect of MANF deficiency on acute binge alcohol exposure-induced neurobehavioral deficits and ER stress. Adult male and female MANF KO mice and littermate controls received daily alcohol gavage (5 g/kg) for 10 days and then subjected to a battery of neurobehavioral tests including rotarods, balance beam, DigiGait, open field, elevated plus maze, Barnes maze, and three-chamber sociability task. Female MANF KO animals were more susceptible to alcohol-induced body weight loss. Alcohol exposure did not affect motor function, however female but not male MANF KO mice exhibited an increased locomotor activity in open field test. Learning and memory was not significantly impaired, but it was altered by MANF deficiency in females while it was affected by alcohol treatment in males. Both alcohol-exposed male and female MANF KO mice displayed increased sociability. Alcohol induced the expression of ER chaperones GRP78 and GRP94 and altered the levels of several unfolded protein response (UPR) and neuroinflammation markers in MANF KO mice in a sex-specific manner. The expression of MANF interacting proteins neuroplastin, PDIA1, and PDIA6 was increased in MANF KO mice, and was further induced by alcohol. In conclusion, alcohol exposure and neuronal MANF deficiency interacted to alter neurobehavioral outcomes, ER homeostasis and neuroinflammation in a sex-specific manner.

Methamphetamine and the Synthetic Cathinone 3,4-Methylenedioxypyrovalerone (MDPV) Produce Persistent Effects on Prefrontal and Striatal Microglial Morphology and Neuroimmune Signaling Following Repeated Binge-like Intake in Male and Female Rats

Psychostimulants alter cellular morphology and activate neuroimmune signaling in a number of brain regions, yet few prior studies have investigated their persistence beyond acute abstinence or following high levels of voluntary drug intake. In this study, we examined the effects of the repeated binge-like self-administration (96 h/week for 3 weeks) of methamphetamine (METH) and 21 days of abstinence in female and male rats on changes in cell density, morphology, and cytokine levels in two addiction-related brain regions-the prefrontal cortex (PFC) and dorsal striatum (DStr). We also examined the effects of similar patterns of intake of the cocaine-like synthetic cathinone derivative 3,4-methylenedioxypyrovalerone (MDPV) or saline as a control. Robust levels of METH and MDPV intake (~500-1000 infusions per 96 h period) were observed in both sexes. We observed no changes in astrocyte or neuron density in either region, but decreases in dendritic spine densities were observed in PFC pyramidal and DStr medium spiny neurons. The microglial cell density was decreased in the PFC of METH self-administering animals, accompanied by evidence of microglial apoptosis. Changes in microglial morphology (e.g., decreased territorial volume and ramification and increased cell soma volume) were also observed, indicative of an inflammatory-like state. Multiplex analyses of PFC and DStr cytokine content revealed elevated levels of various interleukins and chemokines only in METH self-administering animals, with region- and sex-dependent effects. Our findings suggest that voluntary binge-like METH or MDPV intake induces similar cellular perturbations in the brain, but they are divergent neuroimmune responses that persist beyond the initial abstinence phase.

Influence of sex and liver cirrhosis on the expression of miR-146a-5p and its target genes, IRAK1 and TRAF6

Long-term alcohol misuse triggers cellular adaptions in susceptible regions of the human brain, resulting in neurodegeneration, neuroinflammation and altered gene expression. Previous studies have identified ∼35 miRNAs, including miR-146a-5p, which are up-regulated in the frontal cortex of males with alcohol use disorder (AUD), but the influence of liver cirrhosis and sex is unknown. The expression of miR-146a-5p, IRAK1, and TRAF6 was measured in the prefrontal cortex of controls and individuals with AUD with and without cirrhosis of the liver. Further, individuals were genotyped for two SNPs, rs2910164 and rs57095329. The expression of miR-146a-5p was significantly different between sexes. In males the expression of miR-146a-5p was increased in individuals with AUD with and without liver cirrhosis compared with controls. In females miR-146a-5p expression was significantly lower in individuals with AUD compared with both controls and those with AUD and cirrhosis, suggesting that both the severity of alcohol misuse and the sex of the individual influences the expression of miR-146a-5p. The expression of TRAF6 was significantly lower in individuals with uncomplicated AUD compared with those with AUD and cirrhosis. The expression of IRAK1 did not differ between groups or sexes. There was no influence of genotype on expression. Increased expression of miR-146a-5p did not correlate with decreased IRAK1 or TRAF6 expression suggesting a loss of regulatory control of the TLR4 pathway. Understanding sex-specific differences in the regulation of gene expression in AUD is key to determine which inflammatory pathways could be targeted for therapeutic intervention.

Neuroimmune Activation and Microglia Reactivity in Female Rats Following Alcohol Dependence

The rates of alcohol use disorder among women are growing, yet little is known about how the female brain is affected by alcohol. The neuroimmune system, and specifically microglia, have been implicated in mediating alcohol neurotoxicity, but most preclinical studies have focused on males. Further, few studies have considered changes to the microglial phenotype when examining the effects of ethanol on brain structure and function. Therefore, we quantified microglial reactivity in female rats using a binge model of alcohol dependence, assessed through morphological and phenotypic marker expression, coupled with regional cytokine levels. In a time- and region-dependent manner, alcohol altered the microglial number and morphology, including the soma and process area, and the overall complexity within the corticolimbic regions examined, but no significant increases in the proinflammatory markers MHCII or CD68 were observed. The majority of cytokine and growth factor levels examined were similarly unchanged. However, the expression of the proinflammatory cytokine TNFα was increased, and the anti-inflammatory IL-10, decreased. Thus, female rats showed subtle differences in neuroimmune reactivity compared to past work in males, consistent with reports of enhanced neuroimmune responses in females across the literature. These data suggest that specific neuroimmune reactions in females may impact their susceptibility to alcohol neurotoxicity and other neurodegenerative events with microglial contributions.

Novel insight into the lipid network of plasma extracellular vesicles reveal sex-based differences in the lipidomic profile of alcohol use disorder patients

BACKGROUND

Alcohol use disorder (AUD) is one of the most common psychiatric disorders, with the consumption of alcohol considered a leading cause of preventable deaths worldwide. Lipids play a crucial functional role in cell membranes; however, we know little about the role of lipids in extracellular vesicles (EVs) as regulatory molecules and disease biomarkers.

METHODS

We employed a sensitive lipidomic strategy to characterize lipid species from the plasma EVs of AUD patients to evaluate functional roles and enzymatic activity networks to improve the knowledge of lipid metabolism after alcohol consumption. We analyzed plasma EV lipids from AUD females and males and healthy individuals to highlight lipids with differential abundance and biologically interpreted lipidomics data using LINEX2, which evaluates enzymatic dysregulation using an enrichment algorithm.

RESULTS

Our results show, for the first time, that AUD females exhibited more significant substrate-product changes in lysophosphatidylcholine/phosphatidylcholine lipids and phospholipase/acyltransferase activity, which are potentially linked to cancer progression and neuroinflammation. Conversely, AUD males suffer from dysregulated ceramide and sphingomyelin lipids involving sphingomyelinase, sphingomyelin phosphodiesterase, and sphingomyelin synthase activity, which relates to hepatotoxicity. Notably, the analysis of plasma EVs from AUD females and males demonstrates enrichment of lipid ontology terms associated with "negative intrinsic curvature" and "positive intrinsic curvature", respectively.

CONCLUSIONS

Our methodological developments support an improved understanding of lipid metabolism and regulatory mechanisms, which contribute to the identification of novel lipid targets and the discovery of sex-specific clinical biomarkers in AUD.

Predominantly Pro-Inflammatory Phenotype with Mixed M1/M2 Polarization of Peripheral Blood Classical Monocytes and Monocyte-Derived Macrophages among Patients with Excessive Ethanol Intake

Excessive alcohol consumption impairs the immune system, induces oxidative stress, and triggers the activation of peripheral blood (PB) monocytes, thereby contributing to alcoholic liver disease (ALD). We analyzed the M1/M2 phenotypes of circulating classical monocytes and macrophage-derived monocytes (MDMs) in excessive alcohol drinkers (EADs). PB samples from 20 EADs and 22 healthy controls were collected for isolation of CD14+ monocytes and short-term culture with LPS/IFNγ, IL4/IL13, or without stimulation. These conditions were also used to polarize MDMs into M1, M2, or M0 phenotypes. Cytokine production was assessed in the blood and culture supernatants. M1/M2-related markers were analyzed using mRNA expression and surface marker detection. Additionally, the miRNA profile of CD14+ monocytes was analyzed. PB samples from EADs exhibited increased levels of pro-inflammatory cytokines. Following short-term culture, unstimulated blood samples from EADs showed higher levels of soluble TNF-α and IL-8, whereas monocytes expressed increased levels of surface TNF-α and elevated mRNA expression of pro-inflammatory cytokines and inducible nitric oxide synthase. MDMs from EADs showed higher levels of TNF-α and CD206 surface markers and increased IL-10 production. LPS/IFNγ induced higher mRNA expression of Nrf2 only in the controls. miRNA analysis revealed a distinctive miRNA profile that is potentially associated with liver carcinogenesis and ALD through inflammation and oxidative stress. This study confirms the predominantly pro-inflammatory profile of PB monocytes among EADs and suggests immune exhaustion features in MDMs.

Sex-dependent factors of alcohol and neuroimmune mechanisms

Excessive alcohol use disrupts neuroimmune signaling across various cell types, including neurons, microglia, and astrocytes. The present review focuses on recent, albeit limited, evidence of sex differences in biological factors that mediate neuroimmune responses to alcohol and underlying neuroimmune systems that may influence alcohol drinking behaviors. Females are more vulnerable than males to the neurotoxic and negative consequences of chronic alcohol drinking, reflected by elevations of pro-inflammatory cytokines and inflammatory mediators. Differences in cytokine, microglial, astrocytic, genomic, and transcriptomic evidence suggest females are more reactive than males to neuroinflammatory changes after chronic alcohol exposure. The growing body of evidence supports that innate immune factors modulate synaptic transmission, providing a mechanistic framework to examine sex differences across neurocircuitry. Targeting neuroimmune signaling may be a viable strategy for treating AUD, but more research is needed to understand sex-specific differences in alcohol drinking and neuroimmune mechanisms.

Associations of Adherence to the 2018 World Cancer Research Fund and the American Institute for Cancer Research Dietary Recommendations with Gut Microbiota and Inflammation Levels

BACKGROUND

Whether the World Cancer Research Fund and the American Institute for Cancer Research (WCRF/AICR) dietary recommendations affect the gut microbiota and inflammatory status remains unclear. We examined the association of dietary adherence scores to the WCRF/AICR with gut microbiota and inflammation in a cross-sectional setting.

METHODS

The WCRF/AICR diet adherence scores were calculated for 151 participants (adenoma 97, non-adenoma 54) from 7-day dietary records. The gut microbiota was analyzed by 16S rRNA gene sequencing of fecal samples. The levels of inflammatory biomarkers in both blood (i.e., IL-6, IL-8, IgA, IgM, and IgG) and fecal samples (i.e., FCP) were evaluated in 97 colorectal adenoma patients who had blood samples available. Multivariable linear regression analyses were conducted to examine the association of individual and total dietary adherence scores with gut microbiota and inflammatory biomarker levels.

RESULTS

Participants with higher adherence had lower relative abundance of Proteobacteria (β = -0.041, 95%CI: -0.073, -0.009), Enterobacteriaceae (β = -0.035, 95%CI: -0.067, -0.003), and unidentified Enterobacteriaceae at the genus level (β = -0.029, 95%CI: -0.055, -0.003) compared to those with lower adherence. Plant-based food intake was positively correlated with increased abundance of Phascolarctobacterium (β = 0.013, 95%CI: 0.001, 0.026). Restricting fast food was linked to high abundance of Bacteroidaceae (β = 0.149, 95%CI: 0.040, 0.257) and Bacteroides (β = 0.149, 95%CI: 0.040, 0.257). Limiting sugary drinks was associated with reduced abundance of Lachnospiraceae (β = -0.155, 95%CI: -0.292, -0.018). Plant-based food intake (β = -0.251, 95%CI: -0.450, -0.052) and restriction of fast food (β = -0.226, 95%CI: -0.443, -0.008) were associated with reduced IGG levels in men. Alcohol restriction was linked to lower IL-6 (β = -7.095, 95%CI: -11.286, -2.903) and IL-8 (β = -7.965, 95%CI: -14.700, -1.230) levels in women, but with higher IL-6 (β = 0.918, 95%CI: 0.161, 1.675) levels in men.

CONCLUSIONS

Our findings support the association of adherence to the WCRF/AICR diet with gut microbiota and inflammation. These results need to be validated in additional prospective or interventional studies.

Intermittent Exposure to a Single Bottle of Ethanol Modulates Stress Sensitivity: Impact of Age at Exposure Initiation

Alcohol use during adolescence is a serious public health problem, with binge drinking and high-intensity drinking being particularly harmful to the developing adolescent brain. To investigate the adverse consequences of binge drinking and high-intensity adolescent drinking, adolescent rodents were intermittently exposed to ethanol through intragastric gavage, intraperitoneal injection, or vapor inhalation. These models revealed the long-lasting behavioral and neural consequences of adolescent intermittent ethanol (AIE) exposure. The present study was designed to characterize a different AIE model, namely, intermittent exposure to a single bottle of 10% ethanol as the only source of fluids on a 2 days on/2 days off (water days) schedule, and to determine whether this AIE exposure model would produce changes in hormonal and neuroimmune responsiveness to challenges of differing modalities. Assessments of ethanol intake as well as blood and brain ethanol concentrations (BECs and BrECs, respectively) in adult male and female rats (Experiment 1) revealed that BECs and BrECs peaked following access to ethanol for a 2 h period when assessed 1 h into the dark cycle. Experiment 2 revealed age differences in ethanol intake, BECs, and BrECs following a 2 h access to ethanol (1 h into the dark cycle), with adolescents ingesting more ethanol and reaching higher BECs as well as BrECs than adults. In Experiment 3, intermittent exposure to a single bottle of 10% ethanol for 10 cycles of 2 days on/2 days off was initiated either in early or late adolescence, followed by an acute systemic immune challenge with lipopolysaccharide (LPS) in adulthood. LPS increased corticosterone and progesterone levels regardless of sex and prior ethanol history, whereas an LPS-induced increase in cytokine gene expression in the hippocampus was evident only in ethanol-exposed males and females, with females who underwent early exposure to ethanol being more affected than their later-exposed counterparts. In Experiment 4, intermittent ethanol exposure in females was initiated either in adolescence or adulthood and lasted for 12 ethanol exposure cycles. Then, behavioral (freezing behavior), hormonal (corticosterone and progesterone levels), and neuroimmune (cytokine gene expression in the PVN, amygdala, and hippocampus) responses to novel environments (mild stressors) and shock (intense stressors) were assessed. More pronounced behavioral and hormonal changes, as well as changes in cytokine gene expression, were evident in the shock condition than following placement in the novel environment, with prior history of ethanol exposure not playing a substantial role. Interleukin (IL)-1β gene expression was enhanced by shock in the PVN, whereas shock-induced increases in IL-6 gene expression were evident in the hippocampus. Together, these findings demonstrate that our intermittent adolescent exposure model enhances responsiveness to immune but not stress challenges, with females being more vulnerable to this AIE effect than males.

Imaging the brain's immune response to alcohol with [11C]PBR28 TSPO Positron Emission Tomography

In humans, the negative effects of alcohol are linked to immune dysfunction in both the periphery and the brain. Yet acute effects of alcohol on the neuroimmune system and its relationships with peripheral immune function are not fully understood. To address this gap, immune response to an alcohol challenge was measured with positron emission tomography (PET) using the radiotracer [11C]PBR28, which targets the 18-kDa translocator protein, a marker sensitive to immune challenges. Participants (n = 12; 5 F; 25-45 years) who reported consuming binge levels of alcohol (>3 drinks for females; >4 drinks for males) 1-3 months before scan day were enrolled. Imaging featured a baseline [11C]PBR28 scan followed by an oral laboratory alcohol challenge over 90 min. An hour later, a second [11C]PBR28 scan was acquired. Dynamic PET data were acquired for at least 90 min with arterial blood sampling to measure the metabolite-corrected input function. [11C]PBR28 volume of distributions (VT) was estimated in the brain using multilinear analysis 1. Subjective effects, blood alcohol levels (BAL), and plasma cytokines were measured during the paradigm. Full completion of the alcohol challenge and data acquisition occurred for n = 8 (2 F) participants. Mean peak BAL was 101 ± 15 mg/dL. Alcohol significantly increased brain [11C]PBR28 VT (n = 8; F(1,49) = 34.72, p > 0.0001; Cohen's d'=0.8-1.7) throughout brain by 9-16%. Alcohol significantly altered plasma cytokines TNF-α (F(2,22) = 17.49, p < 0.0001), IL-6 (F(2,22) = 18.00, p > 0.0001), and MCP-1 (F(2,22) = 7.02, p = 0.004). Exploratory analyses identified a negative association between the subjective degree of alcohol intoxication and changes in [11C]PBR28 VT. These findings provide, to our knowledge, the first in vivo human evidence for an acute brain immune response to alcohol.

Cocaine Regulates NLRP3 Inflammasome Activity and CRF Signaling in a Region- and Sex-Dependent Manner in Rat Brain

Cocaine, one of the most abused drugs worldwide, is capable of activating microglia in vitro and in vivo. Several neuroimmune pathways have been suggested to play roles in cocaine-mediated microglial activation. Previous work showed that cocaine activates microglia in a region-specific manner in the brains of self-administered mice. To further characterize the effects of cocaine on microglia and neuroimmune signaling in vivo, we utilized the brains from both sexes of outbred rats with cocaine self-administration to explore the activation status of microglia, NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activity, corticotropin-releasing factor (CRF) signaling, and NF-κB levels in the striatum and hippocampus (HP). Age-matched rats of the same sex (drug naïve) served as controls. Our results showed that cocaine increased neuroinflammation in the striatum and HP of both sexes with a relatively higher increases in male brains. In the striatum, cocaine upregulated NLRP3 inflammasome activity and CRF levels in males but not in females. In contrast, cocaine increased NLRP3 inflammasome activity in the HP of females but not in males, and no effects on CRF signaling were observed in this region of either sex. Interestingly, cocaine increased NF-κB levels in the striatum and HP with no sex difference. Taken together, our results provide evidence that cocaine can exert region- and sex-specific differences in neuroimmune signaling in the brain. Targeting neuroimmune signaling has been suggested as possible treatment for cocaine use disorders (CUDs). Our current results indicate that sex should be taken into consideration when determining the efficacy of these new therapeutic approaches.

Aerobic Physical Training Attenuates Oxidative Stress in the Spinal Cord of Adult Rats Induced by Binge-like Ethanol Intake

Binge drinking is the most frequent consumption pattern among young adults and remarkably changes the central nervous system; thus, research on strategies to protect it is relevant. This study aimed to investigate the detrimental effects of binge-like EtOH intake on the spinal cord of male rats and the potential neuroprotective effects provided by moderate-intensity aerobic physical training. Male Wistar rats were distributed into the 'control group', 'training group', 'EtOH group', and 'training + EtOH'. The physical training protocol consisted of daily 30-min exercise on a treadmill for 5 consecutive days followed by 2 days off during 4 weeks. After the fifth day of each week, distilled water ('control group' and 'training group') or 3 g/kg of EtOH diluted at 20% w/v ('EtOH group' and 'training + EtOH group') was administered for 3 consecutive days through intragastric gavage to simulate compulsive consumption. Spinal cord samples were collected for oxidative biochemistry and morphometric analyses. The binge-like EtOH intake induced oxidative and tissue damage by decreasing reduced glutathione (GSH) levels, increasing lipid peroxidation (LPO), and reducing motor neurons (MN) density in the cervical segment. Even under EtOH exposure, physical training maintained GSH levels, reduced LPO, and prevented MN reduction at the cervical segment. Physical training is a non-pharmacological strategy to neuroprotect the spinal cord against oxidative damage induced by binge-like EtOH intake.

Chronic ethanol induces a pro-inflammatory switch in interleukin-1β regulation of GABAergic signaling in the medial prefrontal cortex of male mice

Neuroimmune pathways regulate brain function to influence complex behavior and play a role in several neuropsychiatric diseases, including alcohol use disorder (AUD). In particular, the interleukin-1 (IL-1) system has emerged as a key regulator of the brain's response to ethanol (alcohol). Here we investigated the mechanisms underlying ethanol-induced neuroadaptation of IL-1β signaling at GABAergic synapses in the prelimbic region of the medial prefrontal cortex (mPFC), an area responsible for integrating contextual information to mediate conflicting motivational drives. We exposed C57BL/6J male mice to the chronic intermittent ethanol vapor-2 bottle choice paradigm (CIE-2BC) to induce ethanol dependence, and conducted ex vivo electrophysiology and molecular analyses. We found that the IL-1 system regulates basal mPFC function through its actions at inhibitory synapses on prelimbic layer 2/3 pyramidal neurons. IL-1β can selectively recruit either neuroprotective (PI3K/Akt) or pro-inflammatory (MyD88/p38 MAPK) mechanisms to produce opposing synaptic effects. In ethanol naïve conditions, there was a strong PI3K/Akt bias leading to a disinhibition of pyramidal neurons. Ethanol dependence produced opposite IL-1 effects - enhanced local inhibition via a switch in IL-1β signaling to the canonical pro-inflammatory MyD88 pathway. Ethanol dependence also increased cellular IL-1β in the mPFC, while decreasing expression of downstream effectors (Akt, p38 MAPK). Thus, IL-1β may represent a key neural substrate in ethanol-induced cortical dysfunction. As the IL-1 receptor antagonist (kineret) is already FDA-approved for other diseases, this work underscores the high therapeutic potential of IL-1 signaling/neuroimmune-based treatments for AUD.

Implication of the PTN/RPTPβ/ζ Signaling Pathway in Acute Ethanol Neuroinflammation in Both Sexes: A Comparative Study with LPS

Binge drinking during adolescence increases the risk of alcohol use disorder, possibly by involving alterations of neuroimmune responses. Pleiotrophin (PTN) is a cytokine that inhibits Receptor Protein Tyrosine Phosphatase (RPTP) β/ζ. PTN and MY10, an RPTPβ/ζ pharmacological inhibitor, modulate ethanol behavioral and microglial responses in adult mice. Now, to study the contribution of endogenous PTN and the implication of its receptor RPTPβ/ζ in the neuroinflammatory response in the prefrontal cortex (PFC) after acute ethanol exposure in adolescence, we used MY10 (60 mg/kg) treatment and mice with transgenic PTN overexpression in the brain. Cytokine levels by X-MAP technology and gene expression of neuroinflammatory markers were determined 18 h after ethanol administration (6 g/kg) and compared with determinations performed 18 h after LPS administration (5 g/kg). Our data indicate that Ccl2, Il6, and Tnfa play important roles as mediators of PTN modulatory actions on the effects of ethanol in the adolescent PFC. The data suggest PTN and RPTPβ/ζ as targets to differentially modulate neuroinflammation in different contexts. In this regard, we identified for the first time important sex differences that affect the ability of the PTN/RPTPβ/ζ signaling pathway to modulate ethanol and LPS actions in the adolescent mouse brain.

Lipidomic landscape of circulating extracellular vesicles isolated from adolescents exposed to ethanol intoxication: a sex difference study

BACKGROUND

Lipids represent essential components of extracellular vesicles (EVs), playing structural and regulatory functions during EV biogenesis, release, targeting, and cell uptake. Importantly, lipidic dysregulation has been linked to several disorders, including metabolic syndrome, inflammation, and neurological dysfunction. Our recent results demonstrated the involvement of plasma EV microRNAs as possible amplifiers and biomarkers of neuroinflammation and brain damage induced by ethanol intoxication during adolescence. Considering the possible role of plasma EV lipids as regulatory molecules and biomarkers, we evaluated how acute ethanol intoxication differentially affected the lipid composition of plasma EVs in male and female adolescents and explored the participation of the immune response.

METHODS

Plasma EVs were extracted from humans and wild-type (WT) and Toll-like receptor 4 deficient (TLR4-KO) mice. Preprocessing and exploratory analyses were conducted after the extraction of EV lipids and data acquisition by mass spectrometry. Comparisons between ethanol-intoxicated and control human female and male individuals and ethanol-treated and untreated WT and TLR4-KO female and male mice were used to analyze the differential abundance of lipids. Annotation of lipids into their corresponding classes and a lipid set enrichment analysis were carried out to evaluate biological functions.

RESULTS

We demonstrated, for the first time, that acute ethanol intoxication induced a higher enrichment of distinct plasma EV lipid species in human female adolescents than in males. We observed a higher content of the PA, LPC, unsaturated FA, and FAHFA lipid classes in females, whereas males showed enrichment in PI. These lipid classes participate in the formation, release, and uptake of EVs and the activation of the immune response. Moreover, we observed changes in EV lipid composition between ethanol-treated WT and TLR4-KO mice (e.g., enrichment of glycerophosphoinositols in ethanol-treated WT males), and the sex-based differences in lipid abundance are more notable in WT mice than in TLR4-KO mice. All data and results generated have been made openly available on a web-based platform ( http://bioinfo.cipf.es/sal ).

CONCLUSIONS

Our results suggest that binge ethanol drinking in human female adolescents leads to a higher content of plasma EV lipid species associated with EV biogenesis and the propagation of neuroinflammatory responses than in males. In addition, we discovered greater differences in lipid abundance between sexes in WT mice compared to TLR4-KO mice. Our findings also support the potential use of EV-enriched lipids as biomarkers of ethanol-induced neuroinflammation during adolescence.

Adolescent brain maturation and the neuropathological effects of binge drinking: A critical review

Adolescence is a transitional stage marked by continued brain development. This period is accompanied by physical and neurochemical modifications in the shape and function of the hippocampus, prefrontal cortex, and other limbic system structures. Brain maturation during adolescence, which is typically governed by intrinsic factors, can be dramatically altered by environmental influences such as drugs and alcohol. Unlike many other addictive substances, binge drinking is very common and normative among teenagers and young adults. This repeated pattern of excessive alcohol consumption in adolescents has been shown to cause behavioral changes and neurocognitive impairments that include increased anxiety, risky decision-making, and learning deficits, which could lead to the development of alcohol use disorder (AUD). This manuscript highlights factors that lead to adolescent binge drinking, discusses maturational changes that occur in an adolescent's brain, and then evaluates the effect of adolescent alcohol consumption on brain structure, function, and neurocognitive abilities in both human studies and animal models. The impact of gender/sex and COVID-19 are briefly discussed. Understanding the factors that promote the onset of adolescent binge drinking and its undesirable consequences could serve as a catalyst for developing therapeutic agents that would decrease or eradicate the damaging effects of alcohol on an adolescent brain.

Alcohol Drinking Patterns and Laboratory Indices of Health: Does Type of Alcohol Preferred Make a Difference?

Although excessive alcohol consumption is a highly prevalent public health problem the data on the associations between alcohol consumption and health outcomes in individuals preferring different types of alcoholic beverages has remained unclear. We examined the relationships between the amounts and patterns of drinking with the data on laboratory indices of liver function, lipid status and inflammation in a national population-based health survey (FINRISK). Data on health status, alcohol drinking, types of alcoholic beverages preferred, body weight, smoking, coffee consumption and physical activity were recorded from 22,432 subjects (10,626 men, 11,806 women), age range 25-74 years. The participants were divided to subgroups based on the amounts of regular alcohol intake (abstainers, moderate and heavy drinkers), patterns of drinking (binge or regular) and the type of alcoholic beverage preferred (wine, beer, cider or long drink, hard liquor or mixed). Regular drinking was found to be more typical in wine drinkers whereas the subjects preferring beer or hard liquor were more often binge-type drinkers and cigarette smokers. Alcohol use in all forms was associated with increased frequencies of abnormalities in the markers of liver function, lipid status and inflammation even at rather low levels of consumption. The highest rates of abnormalities occurred, however, in the subgroups of binge-type drinkers preferring beer or hard liquor. These results demonstrate that adverse consequences of alcohol occur even at moderate average drinking levels especially in individuals who engage in binge drinking and in those preferring beer or hard liquor. Further emphasis should be placed on such patterns of drinking in policies aimed at preventing alcohol-induced adverse health outcomes.

Repeated Cycles of Binge-Like Ethanol Exposure Induces Neurobehavioral Changes During Short- and Long-Term Withdrawal in Adolescent Female Rats

Alcohol consumption is spread worldwide and can lead to an abuse profile associated with severe health problems. Adolescents are more susceptible to addiction and usually consume ethanol in a binge drinking pattern. This form of consumption can lead to cognitive and emotional disorders, however scarce studies have focused on long-term hazardous effects following withdrawal periods after binge drinking in adolescents. Thus, the present study aims at investigating whether behavioral and cognitive changes persist until mid and late adulthood. Female Wistar rats (9-10 animals/group) received intragastric administration of four cycles of ethanol binge-like pattern (3.0 g/kg/day, 20% w/v; 3 days-on/4 days-off) from 35^th to 58^th days old, followed withdrawal checkpoints 1 day, 30 days, and 60 days. At each checkpoint period, behavioral tests of open field, object recognition test, elevated plus maze, and forced swimming test were performed, and blood and hippocampus were collected for oxidative biochemistry and brain-derived neurotrophic factor (BDNF) levels analysis, respectively. The results demonstrated that adolescent rats exposed to binge drinking displayed anxiogenic- and depressive-like phenotype in early and midadulthood, however, anxiety-like profile persisted until late adulthood. Similarly, short-term memory was impaired in all withdrawal periods analysed, including late adult life. These behavioral data were associated with oxidative damage in midadulthood but not BDNF alterations. Taken together, the present work highlights the long-lasting emotional and cognitive alterations induced by ethanol binge drinking during adolescence, even after a long period of abstinence, which might impact adult life.

Sex differences in stress-induced alcohol intake: a review of preclinical studies focused on amygdala and inflammatory pathways

Clinical studies suggest that women are more likely than men to relapse to alcohol drinking in response to stress; however, the mechanisms underlying this sex difference are not well understood. A number of preclinical behavioral models have been used to study stress-induced alcohol intake. Here, we review paradigms used to study effects of stress on alcohol intake in rodents, focusing on findings relevant to sex differences. To date, studies of sex differences in stress-induced alcohol drinking have been somewhat limited; however, there is evidence that amygdala-centered circuits contribute to effects of stress on alcohol seeking. In addition, we present an overview of inflammatory pathways leading to microglial activation that may contribute to alcohol-dependent behaviors. We propose that sex differences in neuronal function and inflammatory signaling in circuits centered on the amygdala are involved in sex-dependent effects on stress-induced alcohol seeking and suggest that this is an important area for future studies.

Ovarian Steroids Mediate Sex Differences in Alcohol Reward After Brain Injury in Mice

Intoxication is a leading risk factor for injury, and TBI increases the risk for later alcohol misuse, especially when the injury is sustained in childhood. Previously, we modeled this pattern in mice, wherein females injured at postnatal day 21 drank significantly more than uninjured females, while we did not see this effect in males. However, the biological underpinnings of this sex difference have remained elusive. In this study, we utilize this preclinical model and traditional endocrine manipulations to assess the effect of perinatal sex steroids on post-injury ethanol response. We found that perinatal androgen administration and adult ovariectomy prevented the development of conditioned place preference to ethanol in females, while there was not an effect of gonadectomy either developmental time point on the severity of axonal degeneration. Finally, although TBI increased the number of microglia in males, there was no corresponding effect of gonadectomy, which suggests that males exhibit prolonged neuroinflammation after brain injury irrespective of circulating sex steroids. Taken together, our results indicate a potential role for ovarian sex steroids in the development of greater alcohol preference after a juvenile TBI in female mice.

Chronic Ethanol Causes Persistent Increases in Alzheimer's Tau Pathology in Female 3xTg-AD Mice: A Potential Role for Lysosomal Impairment

Epidemiological studies have found that heavy alcohol use is associated with increased risk for Alzheimer's disease (AD), with frequent drinking earlier in adulthood increasing risk. The increases in neuroinflammation featured in both heavy alcohol use and AD may be partially responsible for this link. However, it is unknown if abstinence mitigates this risk. We hypothesized that binge ethanol during mid adult life would persistently increase AD pathology even after prolonged abstinence. Male and female 3xTg-AD mice (APPSwe, tauP301, Psen1^tm1Mpm) which feature progressive amyloid (Aβ) and tau pathology, received chronic binge ethanol (5g/kg/day, 5-days-on/2-days-off, i.g.) or water during adulthood (from 5.5 to 9 months of age), followed by abstinence and assessment at 14 months of age. The effects of ethanol on protective AD genes (e.g., APOE and TREM2) as well as proinflammatory genes were measured by PCR. Levels of pathologic tau and Aβ were measured by immunohistochemistry and western blot. Ethanol caused persistent reductions in protective AD genes: APOE (25% reduction, *p < 0.05), TREM2 (28%, *p < 0.05), LPL (40%, ^** p < 0.01), and CTSD (24%, *p < 0.05) and promoted a proinflammatory gene signature in female, but not male cortex. Concurrently, ethanol increased total and hyperphosphorylated tau (AT8) in piriform cortex and hippocampus of females, but not males. Levels of AT8 were negatively correlated with APOE (R = -0.67, *p < 0.05) and TREM2 (R = -0.78, ^**p < 0.005) suggesting protective roles in pathogenesis. No differences were found in levels of main regulators of tau phosphorylation state (GSK3β, PKA, PP2A), suggesting ethanol disrupted clearance of tau. Therefore, we measured the effect of ethanol on lysosomes, which degrade tau, and lysosomal localization of tau using co-immunofluorescence. In females, ethanol caused a persistent reduction in mature LAMP1 lysosomes in CA1 of hippocampus (35%, *p < 0.05), along with a 60% increase in total tau (*p < 0.05). Thus, chronic binge ethanol during mid adult life causes a persistent enhancement of tau pathology in cortical and hippocampal brain regions of females. Persistent AD pathology was associated with an increased proinflammatory signature and a reduction of mature lysosomes. This implicates binge ethanol exposure with increased risk of AD pathologic progression in females.

Sex-specific effects of adolescent intermittent ethanol exposure-induced dysregulation of hippocampal glial cells in adulthood

Adolescent alcohol abuse is a significant public health concern, with approximately 4.3 million U.S. adolescents reporting monthly binge drinking. Excessive ethanol consumption during adolescence has been linked to dysregulation of the neuroimmune system, particularly in the hippocampus. Because there are sex differences in both neuroimmune responses and ethanol's pharmacologic actions, this study tested whether there were disparate effects based on sex in glial cells and neurodegeneration in adulthood after the adolescent intermittent ethanol (AIE) model. Male and female adolescent Sprague-Dawley rats underwent AIE. In adulthood, immunohistochemical techniques were utilized to determine the effects of AIE on astrocytes and microglia, and Fluoro-Jade C (FJC) was used to assess neurodegeneration in the hippocampus. AIE exposure significantly increased astrocyte activation in the cornu ammonis 1 (CA1), CA2/3, and dentate gyrus (DG) in both male and female rats with no discernible sex differences in immunoreactivity. Likewise, the number of GFAP + cells was significantly increased by AIE across the hippocampus. In our microglial assessment, AIE only led to increased Iba1 immunoreactivity in the CA1 but not CA2/3 or DG regions. However, the number of Iba1+ cells was increased by AIE in both the CA1 and DG subregions. In the DG, the ethanol effect was observed in both sexes, but in the CA1, AIE-induced increased Iba1 cells were only observed in females. In regard to neurodegeneration, there were no persisting AIE effects on FJC + cells. These findings indicate that AIE alters hippocampal glial cells in adulthood, in the absence of active neurodegeneration. However, while AIE induced long-term elevation of astroglial measures in both males and females, persisting AIE-induced microglial activation was more sparse and sex-dependent. While the majority of these findings suggest that AIE has similar effects on glial morphology and number between males and females, additional work should determine whether there are molecular differences as well as innate sex differences in glial interaction with AIE's influence on glial functions in behavior.

Kappa opioid receptor blockade in the nucleus accumbens shell prevents sex-dependent alcohol deprivation effect induced by inflammatory pain

ABSTRACT

Pain-induced negative affect reduces life quality of patients by increasing psychiatric comorbidities, including alcohol use disorders (AUDs). Indeed, clinical data suggest pain as a risk factor to suffer AUDs, predicting relapse drinking in abstinent patients. Here, we analyse the impact of pain on alcohol relapse and the role of kappa opioid receptor (KOR) activation in mediating these pain-induced effects because KORs play an important role in pain-driven negative affect and AUD. Female and male Sprague-Dawley rats underwent 2 alcohol intermittent access periods separated by a forced abstinence period. The complete Freund adjuvant model of inflammatory pain was introduced during abstinence, and alcohol intake before and after alcohol reintroduction was assessed. In addition, we used behavioural approaches to measure stress and memory impairment and biochemical assays to measure KOR expression in abstinence and reintroduction periods. Only female CFA-treated rats increased alcohol intake during the reintroduction period. Concomitantly, this group showed enhanced anxiety-like behaviour and increased KOR expression in the nucleus accumbens shell that was developed during abstinence and remained during the reintroduction period. Finally, KOR antagonist norbinaltorphimine was administered in the nucleus accumbens shell during abstinence to prevent a pain-induced alcohol deprivation effect, a phenomenon observed in CFA-female rats. The administration of norbinaltorphimine effectively blocked a pain-induced alcohol deprivation effect in female rats. Our data evidenced that inflammatory pain constitutes a risk factor to increase alcohol consumption during a reintroduction phase only in female rats by the rise and maintenance of stress probably mediated by KOR signalling in the nucleus accumbens.

Chemokine profile in women with moderate to severe anxiety and depression during pregnancy

Background

Cytokine levels have been extensively described in pregnant subjects under normal and pathological conditions, including mood-related disorders. Concerning chemokines, very few studies have reported their association with psychiatric disorders during pregnancy. Therefore, we explored the chemokine profile in women exhibiting anxiety and depression during late pregnancy in the present study.

Methods

One hundred twenty-six pregnant women in the 3rd trimester of pregnancy, displaying moderate to severe anxiety (ANX) alone and women exhibiting moderate to severe anxiety with comorbid depression (ANX + DEP), and 40 control pregnant women without affective disorders (CTRL) were evaluated through the Hamilton Anxiety Rating Scale (HARS) and the Hamilton Depression Rating Scale (HDRS). Serum chemokine levels of MCP-1 (CCL2), RANTES (CCL5), IP-10 (CXCL10), Eotaxin (CCL11), TARC (CCL17), MIP-1α (CCL3), MIP-1β (CCL4), MIG (CXCL9), MIP-3α (CCL20), ENA-78 (CXCL5), GROα (CXCL1), I-TAC (CXCL11) and IL-8 (CXCL8)] were measured by immunoassay. Clinical, biochemical, and sociodemographic parameters were correlated with HARS and HDRS score values.

Results

Serum levels of most chemokines were significantly higher in the ANX and in the ANX + DEP groups, when compared to the CTRL group. Positive correlations were observed between MIP-1α/CCL3, MIP-1β/CCL4, MCP-1/CCL2, MIP-3α/CCL20, RANTES/CCL5, Eotaxin/CCL11, and I-TAC/CXCL11 with high scores for anxiety (HARS) (p < 0.05) and for depression (HDRS) (p < 0.004). After controlling clinical measures for age + gwk + BMI, chemokines such as IL-8/CXCL8, MCP-1/CCL2 and MIP-1β/CCL4 were found associated with high scores for anxiety (p < 0.05) in the ANX group. TARC/CCL17 and Eotaxin/CCL11 showed significant associations with high scores for depression (p < 0.04) whereas, MCP-1/CCL2 and MIP-1α/CCL3 were significantly associated with high scores for anxiety (p < 0.05) in the ANX + DEP group. Using a multivariate linear model, high serum levels of MIP-1β/CCL4 and Eotaxin/CCL11 remained associated with depression (p < 0.01), while, IL-8/CXCL8, MIP-1β/CCL4, MCP-1/CCL2, and MIP-1α/CCL3 were associated with anxiety (p < 0.05) in the symptomatic groups.

Conclusions

Our data show that serum levels of distinct chemokines are increased in women exhibiting high levels of affective symptoms during late pregnancy. Our results suggest that increased levels of anxiety, depressive symptoms, and mood-related disorders may promote changes in specific functional chemokines associated with a chronic inflammatory process. If not controlled, it may lead to adverse obstetric and negative neonate outcomes, child development and neuropsychiatric alterations in the postnatal life.

Highlights

Chemokine levels increase in affective disorders during pregnancy.

Contribution of TSPO imaging in the understanding of the state of gliosis in substance use disorders

PURPOSE

Recent research in last years in substance use disorders (SUD) synthesized a proinflammatory hypothesis of SUD based on reported pieces of evidence of non-neuronal central immune signalling pathways modulated by drug of abuse and that contribute to their pharmacodynamic actions. Positron emission tomography has been shown to be a precious imaging technique to study in vivo neurochemical processes involved in SUD and to highlight the central immune signalling actions of drugs of abuse.

METHODS

In this review, we investigate the contribution of the central immune system, with a particular focus on translocator protein 18 kDa (TSPO) imaging, associated with a series of drugs involved in substance use disorders (SUD) specifically alcohol, opioids, tobacco, methamphetamine, cocaine, and cannabis.

RESULTS

The large majority of preclinical and clinical studies presented in this review converges towards SUD modulation of the neuroimmune responses and TSPO expression and speculated a pivotal positioning in the pathogenesis of SUD. However, some contradictions concerning the same drug or between preclinical and clinical studies make it difficult to draw a clear picture about the significance of glial state in SUD.

DISCUSSION

Significant disparities in clinical and biological characteristics are present between investigated populations among studies. Heterogeneity in genetic factors and other clinical co-morbidities, difficult to be reproduced in animal models, may affect findings. On the other hand, technical aspects including study designs, radioligand limitations, or PET imaging quantification methods could impact the study results and should be considered to explain discrepancies in outcomes.

CONCLUSION

The supposed neuroimmune component of SUD provides new therapeutic approaches in the prediction and treatment of SUD pointing to the central immune signalling.

Primed for addiction: A critical review of the role of microglia in the neurodevelopmental consequences of adolescent alcohol drinking

Alcohol is one of the most widely used recreational substances worldwide, with drinking frequently initiated during adolescence. The developmental state of the adolescent brain makes it vulnerable to initiating alcohol use, often in high doses, and particularly susceptible to alcohol-induced brain changes. Microglia, the brain parenchymal macrophages, have been implicated in mediating some of these effects, though the role that these cells play in the progression from alcohol drinking to dependence remains unclear. Microglia are uniquely positioned to sense and respond to central nervous system insult, and are now understood to exhibit innate immune memory, or "priming," altering their future functional responses based on prior exposures. In alcohol use disorders (AUDs), the role of microglia is debated. Whereas microglial activation can be pathogenic, contributing to neuroinflammation, tissue damage, and behavioral changes, or protective, it can also engage protective functions, providing support and mediating the resolution of damage. Understanding the role of microglia in adolescent AUDs is complicated by the fact that microglia are thought to be involved in developmental processes such as synaptic refinement and myelination, which underlie the functional maturation of multiple brain systems in adolescence. Thus, the role microglia play in the impact of alcohol use in adolescence is likely multifaceted. Long-term sequelae may be due to a failure to recover from EtOH-induced tissue damage, altered neurodevelopmental trajectories, and/or persistent changes to microglial responsivity and function. Here, we review critically the literature surrounding the effects of alcohol on microglia in models of adolescent alcohol misuse. We attempt to disentangle what is known about microglia from other neuroimmune effectors, to which we apply recent discoveries on the role of microglia in development and plasticity. Considered altogether, these studies challenge assumptions that proinflammatory microglia drive addiction. Alcohol priming microglia and thereby perturbing their homeostatic roles in neurodevelopment, especially during critical periods of plasticity such as adolescence, may have more serious implications for the neuropathogenesis of AUDs in adolescents.

The emerging tale of microglia in psychiatric disorders

As the professional phagocytes of the brain, microglia orchestrate the immunological response and play an increasingly important role in maintaining homeostatic brain functions. Microglia are activated by pathological events or slight alterations in brain homeostasis. This activation is dependent on the context and type of stressor or pathology. Through secretion of cytokines, chemokines and growth factors, microglia can strongly influence the response to a stressor and can, therefore, determine the pathological outcome. Psychopathologies have repeatedly been associated with long-lasting priming and sensitization of cerebral microglia. This review focuses on the diversity of microglial phenotype and function in health and psychiatric disease. We first discuss the diverse homeostatic functions performed by microglia and then elaborate on context-specific spatial and temporal microglial heterogeneity. Subsequently, we summarize microglia involvement in psychopathologies, namely major depressive disorder, schizophrenia and bipolar disorder, with a particular focus on post-mortem studies. Finally, we postulate microglia as a promising novel therapeutic target in psychiatry through antidepressant and antipsychotic treatment.

Genetic Modulators of Traumatic Brain Injury in Animal Models and the Impact of Sex-Dependent Effects

Traumatic brain injury (TBI) is a major health problem causing disability and death worldwide. There is no effective treatment, due in part to the complexity of the injury pathology and factors affecting its outcome. The extent of brain injury depends on the type of insult, age, sex, lifestyle, genetic risk factors, socioeconomic status, other co-injuries, and underlying health problems. This review discusses the genes that have been directly tested in TBI models, and whether their effects are known to be sex-dependent. Sex differences can affect the incidence, symptom onset, pathology, and clinical outcomes following injury. Adult males are more susceptible at the acute phase and females show greater injury in the chronic phase. TBI is not restricted to a single sex; despite variations in the degree of symptom onset and severity, it is important to consider both female and male animals in TBI pre-clinical research studies.

Immune Response to an Acute Moderate Dose of Alcohol in Healthy Young Adults

Prior research on alcohol and the immune system has tended to focus on binge doses or chronic heavy drinking. The aim of this single-session preliminary study was to characterize immune response to moderate alcohol (0.60 g alcohol per kilogram body weight) in healthy, nonchronic drinkers. The sample (N = 11) averaged 26.6 years of age and was balanced in gender. Plasma samples were collected at baseline and 1, 2 and 3 hours postconsumption. Markers of microbial translocation [lipopolysaccharide (LPS)] and innate immune response [LPS-binding protein (LBP), soluble cluster of differentiation 14 (sCD14), and selected cytokines] were measured using immunoassays. Participants completed self-report questionnaires on subjective alcohol response and craving. Linear mixed models were used to assess changes in biomarkers and self-report measures. Breath alcohol concentration peaked at 0.069 ± 0.008% 1 hour postconsumption. LPS showed a significant linear decrease. LBP and sCD14 showed significant, nonlinear (U-shaped) trajectories wherein levels decreased at 1 hour then rebounded by 3 hours. Of nine cytokines tested, only MCP-1 and IL-8 were detectable in ≥50% of samples. IL-8 did not change significantly. MCP-1 showed a significant linear decrease and also accounted for significant variance in alcohol craving, with higher levels associated with stronger craving. Results offer novel evidence on acute immune response to moderate alcohol. Changes in LBP and sCD14, relative to LPS, may reflect their role in LPS clearance. Results also support further investigation into the role of MCP-1 in alcohol craving. Limitations include small sample size and lack of a placebo condition.

The role of sex in the persistent effects of adolescent alcohol exposure on behavior and neurobiology in rodents

Alcohol drinking is often initiated during adolescence, and this frequently escalates to binge drinking. As adolescence is also a period of dynamic neurodevelopment, preclinical evidence has highlighted that some of the consequences of binge drinking can be long lasting with deficits persisting into adulthood in a variety of cognitive-behavioral tasks. However, while the majority of preclinical work to date has been performed in male rodents, the rapid increase in binge drinking in adolescent female humans has re-emphasized the importance of addressing alcohol effects in the context of sex as a biological variable. Here we review several of the consequences of adolescent ethanol exposure in light of sex as a critical biological variable. While some alcohol-induced outcomes, such as non-social approach/avoidance behavior and sleep disruption, are generally consistent across sex, others are variable across sex, such as alcohol drinking, sensitivity to ethanol, social anxiety-like behavior, and induction of proinflammatory markers.

Pathophysiology of Pediatric Traumatic Brain Injury

The national incidence of traumatic brain injury (TBI) exceeds that of any other disease in the pediatric population. In the United States the Centers for Disease Control and Prevention (CDC) reports 697,347 annual TBIs in children ages 0–19 that result in emergency room visits, hospitalization or deaths. There is a bimodal distribution within the pediatric TBI population, with peaks in both toddlers and adolescents. Preclinical TBI research provides evidence for age differences in acute pathophysiology that likely contribute to long-term outcome differences between age groups. This review will examine the timecourse of acute pathophysiological processes during cerebral maturation, including calcium accumulation, glucose metabolism and cerebral blood flow. Consequences of pediatric TBI are complicated by the ongoing maturational changes allowing for substantial plasticity and windows of vulnerabilities. This review will also examine the timecourse of later outcomes after mild, repeat mild and more severe TBI to establish developmental windows of susceptibility and altered maturational trajectories. Research progress for pediatric TBI is critically important to reveal age-associated mechanisms and to determine knowledge gaps for future studies.

Nalmefene alleviates the neuroimmune response to repeated binge-like ethanol exposure: A TSPO PET imaging study in adolescent rats

A large body of preclinical research has shown that neuroimmunity plays a key role in the deleterious effects of alcohol (ethanol) to the brain. Translational imaging techniques are needed to monitor the efficacy of strategies to prevent or mitigate neuroinflammation and alleviate ethanol-induced neurotoxicity. Opioid receptor antagonists such as nalmefene are antagonists of the toll-like receptor 4, which may block the proinflammatory signaling cascade induced by ethanol at this specific target. Male adolescent rats received a validated protocol of ethanol injection (i.p, 3 g/kg daily for two consecutive days followed by two resting days) during 14 days. Positron emission tomography (PET) imaging with the translocator protein 18 kDa (TSPO) radioligand [¹⁸ F]DPA-714 was performed at day-15. Toxicity induced by repeated binge-like ethanol exposure (71% mortality) was drastically reduced by nalmefene pretreatment (0.4 mg/kg, 14% mortality). No mortality was observed in animals that received vehicle (control) or nalmefene alone. Compared with control animals (n = 10), a significant 2.8-fold to 4.6-fold increase in the volume of distribution (V_T ) of [¹⁸ F]DPA-714 was observed among brain regions in animals exposed to ethanol only (n = 9). Pretreatment with nalmefene significantly alleviated the neuroimmune response to ethanol exposure in all brain regions (1.2-fold to 2.5-fold increase in V_T ; n = 5). Nalmefene alone (n = 6) did not impact [¹⁸ F]DPA-714 V_T compared with the control group. Nalmefene may protect against the neuroinflammatory response and overall toxicity associated with binge drinking. [¹⁸ F]DPA-714 PET imaging can be used to noninvasively address the neuroimmune impact of ethanol exposure and its modulation by pharmacological strategies in vivo, with translational perspectives.

Sex dimorphism in inflammatory response to obesity in childhood

BACKGROUND

Childhood overweight and obesity are a global concern, with prevalence rising dramatically over the last decades. The condition is caused by an increase in energy intake and reduction of physical activity, leading to excessive fat accumulation, followed by systemic chronic inflammation and altered function of immune cell responses. This study aimed at providing new insights regarding sex-specificity on the inflammatory response to obesity in the young patient.

DESIGN

Forty-three Brazilian obese adolescents (Female = 22 and Male=21, BMI (body mass index) Z-score average = 2.78 ± 0.51) and forty-nine eutrophic adolescents (Female = 24 and Male = 25, BMI Z-score average = -0.35 ± 0.88) were enrolled in the study. Anthropometrical analyses and blood cell counts were carried out. Using Luminex®xMAP™ technology, circulating serum cytokines, chemokines, and inflammatory biomarkers were analyzed. Two-way ANOVA test, Tukey's test, and Spearman's correlation coefficient were employed, with a significance threshold set at p < 0.05.

RESULTS

We identified increased levels of serum amyloid A (SAA), platelets, and leukocytes solely in male obese patients. We found a noteworthy sex-dependent pattern in regard to inflammatory response: obese boys showed higher TNFβ, IL15, and IL2 and lower IL10 and IL13, while obese girls showed increased TNFα, CCL3, CCL4, and IP10 content in the circulation. BMI Z-score was significantly linearly correlated with neutrophils, leukocytes, platelets, SAA, TNFα, CCL3, CCL4, IP10, and IL13 levels within the entire cohort (non-sex-dependent).

CONCLUSIONS

Our data support a complex relationship between adiposity, blood cell count, and circulating inflammatory cytokine content. High SAA levels suggest that this factor may play a critical role in local and systemic inflammation. In the eutrophic group, females presented a lower status of inflammation, as compared to males. Both obese boys and girls showed an increased inflammatory response in relation to eutrophic counterparts. Taken together, results point out to clear sex dimorphism in the inflammatory profile of obese adolescents.

Role of mTOR-regulated autophagy in spine pruning defects and memory impairments induced by binge-like ethanol treatment in adolescent mice

Adolescence is a brain maturation developmental period during which remodeling and changes in synaptic plasticity and neural connectivity take place in some brain regions. Different mechanism participates in adolescent brain maturation, including autophagy that plays a role in synaptic development and plasticity. Alcohol is a neurotoxic compound and its abuse in adolescence induces neuroinflammation, synaptic and myelin alterations, neural damage and behavioral impairments. Changes in synaptic plasticity and its regulation by mTOR have also been suggested to play a role in the behavioral dysfunction of binge ethanol drinking in adolescence. Therefore, by considering the critical role of mTOR in both autophagy and synaptic plasticity in the developing brain, the present study aims to evaluate whether binge ethanol treatment in adolescence would induce dysfunctions in synaptic plasticity and cognitive functions and if mTOR inhibition with rapamycin is capable of restoring both effects. Using C57BL/6 adolescent female and male mice (PND30) treated with ethanol (3 g/kg) on two consecutive days at 48-hour intervals over 2 weeks, we show that binge ethanol treatment alters the density and morphology of dendritic spines, effects that are associated with learning and memory impairments and changes in the levels of both transcription factor CREB phosphorylation and miRNAs. Rapamycin administration (3 mg/kg) prior to ethanol administration restores ethanol-induced changes in both plasticity and behavior dysfunctions in adolescent mice. These results support the critical role of mTOR/autophagy dysfunctions in the dendritic spines alterations and cognitive alterations induced by binge alcohol in adolescence.

Tumour Necrosis Factor in Neuroplasticity, Neurogenesis and Alcohol Use Disorder

Alcohol use disorder is a pervasive and detrimental condition that involves changes in neuroplasticity and neurogenesis. Alcohol activates the neuroimmune system and alters the inflammatory status of the brain. Tumour necrosis factor (TNF) is a well characterised neuroimmune signal but its involvement in alcohol use disorder is unknown. In this review, we discuss the variable findings of TNF's effect on neuroplasticity and neurogenesis. Acute ethanol exposure reduces TNF release while chronic alcohol intake generally increases TNF levels. Evidence suggests TNF potentiates excitatory transmission, promotes anxiety during alcohol withdrawal and is involved in drug use in rodents. An association between craving for alcohol and TNF is apparent during withdrawal in humans. While anti-inflammatory therapies show efficacy in reversing neurogenic deficit after alcohol exposure, there is no evidence for TNF's essential involvement in alcohol's effect on neurogenesis. Overall, defining TNF's role in alcohol use disorder is complicated by poor understanding of its variable effects on synaptic transmission and neurogenesis. While TNF may be of relevance during withdrawal, the neuroimmune system likely acts through a larger group of inflammatory cytokines to alter neuroplasticity and neurogenesis. Understanding the individual relevance of TNF in alcohol use disorder awaits a more comprehensive understanding of TNF's effects within the brain.

Sex and Age Effects on Neurobehavioral Toxicity Induced by Binge Alcohol

Historically, most alcohol neurotoxicity studies were conducted in young adult males and focused on chronic intake. There has been a shift towards studying the effects of alcohol on the adolescent brain, due to alcohol consumption during this formative period disrupting the brain's developmental trajectory. Because the most typical pattern of adolescent alcohol intake is heavy episodic (binge) drinking, there has also been a shift towards the study of binge alcohol-induced neurobehavioral toxicity. It has thus become apparent that binge alcohol damages the adolescent brain and there is increasing attention to sex-dependent effects. Significant knowledge gaps remain in our understanding of the effects of binge alcohol on the female brain, however. Moreover, it is unsettling that population-level studies indicate that the prevalence of binge drinking is increasing among American women, particularly those in older age groups. Although study of adolescents has made it apparent that binge alcohol disrupts ongoing brain maturational processes, we know almost nothing about how it impacts the aging brain, as studies of its effects on the aged brain are relatively scarce, and the study of sex-dependent effects is just beginning. Given the rapidly increasing population of older Americans, it is crucial that studies address age-dependent effects of binge alcohol, and given the increase in binge drinking in older women who are at higher risk for cognitive decline relative to men, studies must encompass both sexes. Because adolescence and older age are both characterized by age-typical brain changes, and because binge drinking is the most common pattern of alcohol intake in both age groups, the knowledge that we have amassed on binge alcohol effects on the adolescent brain can inform our study of its effects on the aging brain. In this review, we therefore cover the current state of knowledge of sex and age-dependent effects of binge alcohol, as well as statistical and methodological considerations for studies aimed at addressing them.

Sex Differences in Vagus Nerve Stimulation Effects on Rat Cardiovascular and Immune Systems

Background

Investigations into the benefits of vagus nerve stimulation (VNS) through pre-clinical and clinical research have led to promising findings for treating several disorders. Despite proven effectiveness of VNS on conditions such as epilepsy and depression, understanding of off-target effects and contributing factors such as sex differences can be beneficial to optimize therapy design.

New Methods

In this article, we assessed longitudinal effects of VNS on cardiovascular and immune systems, and studied potential sex differences using a rat model of long-term VNS. Rats were implanted with cuff electrodes around the left cervical vagus nerve for VNS, and wireless physiological monitoring devices for continuous monitoring of cardiovascular system using electrocardiogram (ECG) signals. ECG morphology and heart rate variability (HRV) features were extracted to assess cardiovascular changes resulting from VNS in short-term and long-term timescales. We also assessed VNS effects on expression of inflammatory cytokines in blood during the course of the experiment. Statistical analysis was performed to compare results between Treatment and Sham groups, and between male and female animals from Treatment and Sham groups.

Results

Considerable differences between male and female rats in cardiovascular effects of VNS were observed in multiple cardiovascular features. However, the effects seemed to be transient with approximately 1-h recovery after VNS. While short-term cardiovascular effects were mainly observed in male rats, females in general showed more significant long-term effects even after VNS stopped. We did not observe notable changes or sex differences in systemic cytokine levels resulting from VNS.

Comparison With Existing Methods

Compared to existing methods, our study design incorporated wireless physiological monitoring and systemic blood cytokine level analysis, along with long-term VNS experiments in unanesthetized rats to study sex differences.

Conclusion

The contribution of sex differences for long-term VNS off-target effects on cardiovascular and immune systems was assessed using awake behaving rats. Although VNS did not change the concentration of inflammatory biomarkers in systemic circulation for male and female rats, we observed significant differences in cardiovascular effects of VNS characterized using ECG morphology and HRV analyses.

Daily alcohol intake triggers aberrant synaptic pruning leading to synapse loss and anxiety-like behavior

Alcohol abuse adversely affects the lives of millions of people worldwide. Deficits in synaptic transmission and in microglial function are commonly found in human alcohol abusers and in animal models of alcohol intoxication. Here, we found that a protocol simulating chronic binge drinking in male mice resulted in aberrant synaptic pruning and substantial loss of excitatory synapses in the prefrontal cortex, which resulted in increased anxiety-like behavior. Mechanistically, alcohol intake increased the engulfment capacity of microglia in a manner dependent on the kinase Src, the subsequent activation of the transcription factor NF-κB, and the consequent production of the proinflammatory cytokine TNF. Pharmacological blockade of Src activation or of TNF production in microglia, genetic ablation of Tnf, or conditional ablation of microglia attenuated aberrant synaptic pruning, thereby preventing the neuronal and behavioral effects of the alcohol. Our data suggest that aberrant pruning of excitatory synapses by microglia may disrupt synaptic transmission in response to alcohol abuse.

Circulating MicroRNAs in Extracellular Vesicles as Potential Biomarkers of Alcohol-Induced Neuroinflammation in Adolescence: Gender Differences

Current studies evidence the role of miRNAs in extracellular vesicles (EVs) as key regulators of pathological processes, including neuroinflammation and neurodegeneration. As EVs can cross the blood–brain barrier, and EV miRNAs are very stable in peripheral circulation, we evaluated the potential gender differences in inflammatory-regulated miRNAs levels in human and murine plasma EVs derived from alcohol-intoxicated female and male adolescents, and whether these miRNAs could be used as biomarkers of neuroinflammation. We demonstrated that while alcohol intoxication lowers anti-inflammatory miRNA (mir-146a-5p, mir-21-5p, mir-182-5p) levels in plasma EVs from human and mice female adolescents, these EV miRNAs increased in males. In mice brain cortices, ethanol treatment lowers mir-146a-5p and mir-21-5p levels, while triggering a higher expression of inflammatory target genes (Traf6, Stat3, and Camk2a) in adolescent female mice. These results indicate, for the first time, that female and male adolescents differ as regards the ethanol effects associated with the inflammatory-related plasma miRNAs EVs profile, and suggest that female adolescents are more vulnerable than males to the inflammatory effects of binge alcohol drinking. These findings also support the view that circulating miRNAs in EVs could be useful biomarkers for screening ethanol-induced neuroinflammation and brain damage in adolescence.

N-Acetylcysteine and Acetylsalicylic Acid Inhibit Alcohol Consumption by Different Mechanisms: Combined Protection

Chronic ethanol intake results in brain oxidative stress and neuroinflammation, which have been postulated to perpetuate alcohol intake and to induce alcohol relapse. The present study assessed the mechanisms involved in the inhibition of: (i) oxidative stress; (ii) neuroinflammation; and (iii) ethanol intake that follow the administration of the antioxidant N-acetylcysteine (NAC) and the anti-inflammatory acetylsalicylic acid (ASA) to animals that had consumed ethanol chronically. At doses used clinically, NAC [40 mg/kg per day orally (p.o.)] and ASA (15 mg/kg per day p.o.) significantly inhibited chronic alcohol intake and relapse intake in alcohol-preferring rats. The coadministration of both drugs reduced ethanol intake by 65% to 70%. N-acetylcysteine administration: (a) induced the Nrf2-ARE system, lowering the hippocampal oxidative stress assessed as the ratio of oxidized glutathione (GSSG)/reduced glutathione (GSH); (b) reduced the neuroinflammation assessed by astrocyte and microglial activation by immunofluorescence; and (c) inhibited chronic and relapse ethanol intake. These effects were blocked by sulfasalazine, an inhibitor of the xCT transporter, which incorporates cystine (precursor of GSH) and extrudes extracellular glutamate, an agonist of the inhibitory mGlu2/3 receptor, which lowers the synaptic glutamatergic tone. The inhibitor of mGlu2/3 receptor (LY341495) blocked the NAC-induced inhibition of both relapse ethanol intake and neuroinflammation without affecting the GSSG/GSH ratio. Unlike N-acetylcysteine, ASA inhibited chronic alcohol intake and relapse via lipoxin A4, a strong anti-inflammatory metabolite of arachidonic acid generated following the ASA acetylation of cyclooxygenases. Accordingly, the lipoxin A4 receptor inhibitor, WRW4, blocked the ASA-induced reduction of ethanol intake. Overall, via different mechanisms, NAC and ASA administered in clinically relevant doses combine their effects inhibiting ethanol intake.

CCL2/CCR2 system in neuroepithelial radial glia progenitor cells: involvement in stimulatory, sexually dimorphic effects of maternal ethanol on embryonic development of hypothalamic peptide neurons

BACKGROUND

Clinical and animal studies show that alcohol consumption during pregnancy produces lasting behavioral disturbances in offspring, including increased alcohol drinking, which are linked to inflammation in the brain and disturbances in neurochemical systems that promote these behaviors. These include the neuropeptide, melanin-concentrating hormone (MCH), which is mostly expressed in the lateral hypothalamus (LH). Maternal ethanol administration at low-to-moderate doses, while stimulating MCH neurons without affecting apoptosis or gliogenesis, increases in LH the density of neurons expressing the inflammatory chemokine C-C motif ligand 2 (CCL2) and its receptor CCR2 and their colocalization with MCH. These neural effects associated with behavioral changes are reproduced by maternal CCL2 administration, reversed by a CCR2 antagonist, and consistently stronger in females than males. The present study investigates in the embryo the developmental origins of this CCL2/CCR2-mediated stimulatory effect of maternal ethanol exposure on MCH neurons.

METHODS

Pregnant rats from embryonic day 10 (E10) to E15 during peak neurogenesis were orally administered ethanol at a moderate dose (2 g/kg/day) or peripherally injected with CCL2 or CCR2 antagonist to test this neuroimmune system's role in ethanol's actions. Using real-time quantitative PCR, immunofluorescence histochemistry, in situ hybridization, and confocal microscopy, we examined in embryos at E19 the CCL2/CCR2 system and MCH neurons in relation to radial glia progenitor cells in the hypothalamic neuroepithelium where neurons are born and radial glia processes projecting laterally through the medial hypothalamus that provide scaffolds for neuronal migration into LH.

RESULTS

We demonstrate that maternal ethanol increases radial glia cell density and their processes while stimulating the CCL2/CCR2 system and these effects are mimicked by maternal administration of CCL2 and blocked by a CCR2 antagonist. While stimulating CCL2 colocalization with radial glia and neurons but not microglia, ethanol increases MCH neuronal number near radial glia cells and making contact along their processes projecting into LH. Further tests identify the CCL2/CCR2 system in NEP as a primary source of ethanol's sexually dimorphic actions.

CONCLUSIONS

These findings provide new evidence for how an inflammatory chemokine pathway functions within neuroprogenitor cells to mediate ethanol's long-lasting, stimulatory effects on peptide neurons linked to adolescent drinking behavior.