Non-hiatal diaphragmatic hernias: results of transabdominal and transthoracic surgical approaches at a fourth-level hospital.

OBJECTIVE: The objective of this study is to elucidate the clinical and demographic profiles, as well as perioperative outcomes, of patients undergoing surgery for non-hiatal diaphragmatic hernias. Additionally, it aims to analyse these outcomes based on the surgical approach employed (transthoracic versus transabdominal). METHODS: This retrospective, observational study was conducted at a single center and involved patients diagnosed with non-hiatal diaphragmatic hernia who underwent either emergency or elective surgery between July 2007 and March 2023. Clinical characteristics and perioperative outcomes of these patients were compared using appropriate statistical tests.The research protocol for this observational, retrospective, and comparative study followed the Declaration of Helsinki's ethical requirements. The need for Clinical Research Ethics Committee approval was waived according to our institutional law because the study was a retrospective cohort study based on anonymous data of patients. Informed consent was waived because this study involved the secondary analysis of patient medical records. Additionally, this study followed the STROBE guidelines for reporting observational studies. RESULTS: The analysis included 22 patients being 59.1% men, with median age of 61 years. The predominant clinical presentation was restrictive lung disease (40.9%). The majority of cases (68%) had traumatic aetiology with a median defect size of 4 cm (range of 3-8 cm). Elective surgery was performed in 15 cases (68.1%) and transthoracic approach was employed in 13 patients (54.5%). Postoperative major morbidity reached 27.2% and mortality within 30 days was 9.1%. Emergency surgeries accounted for 44.4% of transabdominal interventions, compared to 23% in the transthoracic subgroup (p = 0.376). There were no statistically significant differences between the transabdominal and trasnthoracic approaches in terms of global postoperative complications (88.8% vs. 84.6%, p = 1), major complications (44.4% vs 15.4%, p = 0.734), mortality (11.1% v 7.6%, p = 1) and recurrence (11.1% vs 7.6%, p = 1). Postoperative stay was significantly shorter in the transthoracic subgroup (6 days vs. 14 days, p = 0.011). CONCLUSIONS: Non-hiatal diaphragmatic hernias are characterized by significant postoperative major morbidity and mortality rates, standing at 27.2% and 9.1%, respectively, accompanied by a recurrence rate of 9.1%. Both transthoracic and transabdominal approaches demonstrate comparable short- and long-term outcomes.

Animal Models of Excessive Alcohol Consumption in Rodents.

The development of animal models that demonstrate excessive levels of alcohol consumption has played an important role in advancing our knowledge about neurobiological underpinnings and environmental circumstances that engender such maladaptive behavior. The use of these preclinical models has also provided valuable opportunities for discovering new and novel therapeutic targets that may be useful in the treatment of alcohol use disorder (AUD). While no single model can fully capture the complexities of AUD, the goal is to develop animal models that closely approximate characteristics of heavy alcohol drinking in humans to enhance their translational value and utility. A variety of experimental approaches have been employed to produce the desired phenotype of interest-robust and reliable excessive levels of alcohol drinking. Here we provide an updated review of five animal models that are commonly used. The models entail procedural manipulations of scheduled access to alcohol (time of day, duration, frequency), periods of time when access to alcohol is withheld, and history of alcohol exposure. Specially, the models involve (a) scheduled access to alcohol, (b) scheduled periods of alcohol deprivation, (c) scheduled intermittent access to alcohol, (d) scheduled-induced polydipsia, and (e) chronic alcohol (dependence) and withdrawal experience. Each of the animal models possesses unique experimental features that engender excessive levels of alcohol consumption. Both advantages and disadvantages of each model are described along with discussion of future work to be considered in developing more optimal models. Ultimately, the validity and utility of these models will lie in their ability to aid in the discovery of new and novel potential therapeutic targets as well as serve as a platform to evaluate treatment strategies that effectively reduce excessive levels of alcohol consumption associated with AUD.

Alcohol Dependence Modifies Brain Networks Activated During Withdrawal and Reaccess: A c-Fos-Based Analysis in Mice.

BACKGROUND: High-level alcohol consumption causes neuroplastic changes in the brain that promote pathological drinking behavior. Some of these changes have been characterized in defined brain circuits and cell types, but unbiased approaches are needed to explore broader patterns of adaptations. METHODS: We used whole-brain c-Fos mapping and network analysis to assess patterns of neuronal activity during alcohol withdrawal and following reaccess in a well-characterized model of alcohol dependence. Mice underwent 4 cycles of chronic intermittent ethanol to increase voluntary alcohol consumption, and a subset underwent forced swim stress to further escalate consumption. Brains were collected either 24 hours (withdrawal) or immediately following a 1-hour period of alcohol reaccess. c-fos counts were obtained for 110 brain regions using iDISCO and ClearMap. Then, we classified mice as high or low drinkers and used graph theory to identify changes in network properties associated with high-drinking behavior. RESULTS: During withdrawal, chronic intermittent ethanol mice displayed widespread increased c-Fos expression relative to air-exposed mice, independent of forced swim stress. Reaccess drinking reversed this increase. Network modularity, a measure of segregation into communities, was increased in high-drinking mice after alcohol reaccess relative to withdrawal. The cortical amygdala showed increased cross-community coactivation during withdrawal in high-drinking mice, and cortical amygdala silencing in chronic intermittent ethanol mice reduced voluntary drinking. CONCLUSIONS: Alcohol withdrawal in dependent mice causes changes in brain network organization that are attenuated by reaccess drinking. Olfactory brain regions, including the cortical amygdala, drive some of these changes and may play an important but underappreciated role in alcohol dependence.

Oxytocin Reduces Sensitized Stress-Induced Alcohol Relapse in a Model of Posttraumatic Stress Disorder and Alcohol Use Disorder Comorbidity.

BACKGROUND: There is high comorbidity of posttraumatic stress disorder (PTSD) and alcohol use disorder with few effective treatment options. Animal models of PTSD have shown increases in alcohol drinking, but effects of stress history on subsequent vulnerability to alcohol relapse have not been examined. Here we present a mouse model of PTSD involving chronic multimodal stress exposure that resulted in long-lasting sensitization to stress-induced alcohol relapse, and this sensitized stress response was blocked by oxytocin (OT) administration. METHODS: Male and female mice trained to self-administer alcohol were exposed to predator odor (TMT) + yohimbine over 5 consecutive days or left undisturbed. After reestablishing stable alcohol responding/intake, mice were tested under extinction conditions, and then all mice were exposed to TMT or context cues previously associated with TMT before a reinstatement test session. Separate studies examined messenger RNA expression of Oxt and Oxtr in hypothalamus following chronic stress exposure. A final study examined the effects of systemic administration of OT on stress-induced alcohol relapse in mice with and without a history of chronic stress experience. RESULTS: Chronic stress exposure produced long-lasting sensitization to subsequent stress-induced alcohol relapse that also generalized to stress-related context cues and transcriptional changes in hypothalamic OT system. OT injected before the reinstatement test session completely blocked the sensitized stress-induced alcohol relapse effect. CONCLUSIONS: Collectively, these results provide support for the therapeutic potential of OT, along with highlighting the value of utilizing this model in evaluating other pharmacological interventions for treatment of PTSD/alcohol use disorder comorbidity.

Chronic intermittent ethanol exposure differentially alters the excitability of neurons in the orbitofrontal cortex and basolateral amygdala that project to the dorsal striatum.

Alcohol use disorder is associated with altered neuron function including those in orbitofrontal cortex (OFC) and basolateral amygdala (BLA) that send glutamatergic inputs to areas of the dorsal striatum (DS) that mediate goal and habit directed actions. Previous studies reported that chronic intermittent (CIE) exposure to ethanol alters the electrophysiological properties of OFC and BLA neurons, although projection targets for these neurons were not identified. In this study, we used male and female mice and recorded current-evoked spiking of retrobead labeled DS-projecting OFC and BLA neurons in the same animals following air or CIE treatment. DS-projecting OFC neurons were hyperexcitable 3- and 7-days following CIE exposure and spiking returned to control levels after 14 days of withdrawal. In contrast, firing was decreased in DS-projecting BLA neurons at 3-days withdrawal, increased at 7- and 14-days and returned to baseline at 28 days post-CIE. CIE exposure enhanced the amplitude and frequency of spontaneous excitatory postsynaptic currents (sEPSCs) of DS-projecting OFC neurons but had no effect on inhibitory postsynaptic currents (sIPSCs). In DS-projecting BLA neurons, the amplitude and frequency of sIPSCs was enhanced 3 days post-CIE with no change in sEPSCs while at 7-days post-withdrawal, sEPSC amplitude and frequency were increased and sIPSCs had returned to normal. Finally, in CIE-treated mice, acute ethanol no longer inhibited spike firing of DS-projecting OFC and BLA neurons. Overall, these results suggest that CIE-induced changes in the excitability of DS-projecting OFC and BLA neurons could underlie deficits in behavioral control often observed in alcohol-dependent individuals.

Agmatine reduces alcohol drinking and produces antinociceptive effects in rodent models of alcohol use disorder.

Alcohol use disorder (AUD) is a chronic, relapsing disorder characterized by an escalation of drinking and the emergence of negative affective states over time. Within this framework, alcohol may be used in excessive amounts to alleviate withdrawal-related symptoms, such as hyperalgesia. Future effective therapeutics for AUD may need to exhibit the ability to reduce drinking as well as to alleviate co-morbid conditions such as pain, and to take mechanistic sex differences into consideration. Agmatine is an endogenous neuromodulator that has been previously implicated in the regulation of reward and pain processing. In the current set of studies, we examined the ability of agmatine to reduce escalated ethanol drinking in complementary models of AUD where adult male and female mice and rats were made dependent via chronic, intermittent ethanol vapor exposure (CIE). We also examined the ability of agmatine to modify thermal and mechanical sensitivity in alcohol-dependent male and female rats. Agmatine reduced alcohol drinking in a dose-dependent fashion, with somewhat greater selectivity in alcohol-dependent female mice (versus non-dependent female mice), but equivalent efficacy across male mice and both groups of male and female rats. In mice and female rats, this efficacy did not extend to sucrose drinking, indicating some selectivity for ethanol reinforcement. Female rats made dependent on alcohol demonstrated significant hyperalgesia symptoms, and agmatine produced dose-dependent antinociceptive effects across both sexes. While additional mechanistic studies into agmatine are necessary, these findings support the broad-based efficacy of agmatine to treat co-morbid excessive drinking and pain symptoms in the context of AUD.

Preclinical and clinical evidence for suppression of alcohol intake by apremilast.

Treatment options for alcohol use disorders (AUDs) have minimally advanced since 2004, while the annual deaths and economic toll have increased alarmingly. Phosphodiesterase type 4 (PDE4) is associated with alcohol and nicotine dependence. PDE4 inhibitors were identified as a potential AUD treatment using a bioinformatics approach. We prioritized a newer PDE4 inhibitor, apremilast, as ideal for repurposing (i.e., FDA approved for psoriasis, low incidence of adverse events, excellent safety profile) and tested it using multiple animal strains and models, as well as in a human phase IIa study. We found that apremilast reduced binge-like alcohol intake and behavioral measures of alcohol motivation in mouse models of genetic risk for drinking to intoxication. Apremilast also reduced excessive alcohol drinking in models of stress-facilitated drinking and alcohol dependence. Using site-directed drug infusions and electrophysiology, we uncovered that apremilast may act to lessen drinking in mice by increasing neural activity in the nucleus accumbens, a key brain region in the regulation of alcohol intake. Importantly, apremilast (90 mg/d) reduced excessive drinking in non-treatment-seeking individuals with AUD in a double-blind, placebo-controlled study. These results demonstrate that apremilast suppresses excessive alcohol drinking across the spectrum of AUD severity.

Predictive factors of prolonged postoperative length of stay after anatomic pulmonary resection.

INTRODUCTION: The objective of this study is to create a predictive model of prolonged postoperative length of stay (PLOS) in patients undergoing anatomic lung resection, to validate it in an external series and to evaluate the influence of PLOS on readmission and 90-day mortality. METHODS: All patients registered in the GEVATS database discharged after the intervention were included. We define PLOS as the postoperative stay in days above the 75th percentile of stay for all patients in the series. A univariate and multivariate analysis was performed using logistic regression and the model was validated in an external cohort. The possible association between PLOS and readmission and mortality at 90 days was analyzed. RESULTS: 3473 patients were included in the study. The median postoperative stay was 5 days (IQR: 4-7). 815 patients had PLOS (≥8 days), of which 79.9% had postoperative complications. The final model included as variables: age, BMI, male sex, ppoFEV1%, ppoDLCO% and thoracotomy; the AUC in the referral series was 0.684 (95% CI: 0.661-0.706) and in the validation series was 0.73 (95% CI: 0.681-0.78). A significant association was found between PLOS and readmission (p < .000) and 90-day mortality (p < .000). CONCLUSIONS: The variables age, BMI, male sex, ppoFEV1%, ppoDLCO% and thoracotomy affect PLOS. PLOS is associated with an increased risk of readmission and 90-day mortality. 20% of PLOS are not related to the occurrence of postoperative complications.

Usefulness of near-infrared fluorescence for identifying the segmental bronchus in minimally invasive segmentectomy.

Minimally invasive anatomical sublobar resections have gained relevance in recent years mainly due to advances in imaging techniques, screening programs and the increase in second neoplasms. Accurate identification of the segmental or subsegmental bronchus is vital to guarantee optimal results in segmentectomies and subsegmentectomies. Given the complexity and the possibility of anatomical variations, several authors have published different methods to identify the target bronchus. However, these methods have certain limitations. This article describes a new rapid and effective technique, with a low risk of complications and without additional cost, for the identification of segmental bronchi in minimally invasive segmentectomies.

Alcohol dependence and the ventral hippocampal influence on alcohol drinking in male mice.

Examining neural circuits underlying persistent, heavy drinking provides insight into the neurobiological mechanisms driving alcohol use disorder. Facilitated by its connectivity with other parts of the brain such as the nucleus accumbens (NAc), the ventral hippocampus (vHC) supports many behaviors, including those related to reward seeking and addiction. These studies used a well-established mouse model of alcohol (ethanol) dependence. After surgery to infuse DREADD-expressing viruses (hM4Di, hM3Dq, or mCherry-only) into the vHC and position guide cannula above the NAc, male C57BL/6J mice were treated in the CIE drinking model that involved repeated cycles of chronic intermittent alcohol (CIE) vapor or air (CTL) exposure alternating with weekly test drinking cycles in which mice were offered alcohol (15% v/v) 2 h/day. Additionally, smaller groups of mice were evaluated for either cFos expression or glutamate release using microdialysis procedures. In CIE mice expressing inhibitory (hM4Di) DREADDs in the vHC, drinking increased as expected, but CNO (3 mg/kg intraperitoneally [i.p.]) given 30 min before testing did not alter alcohol intake. However, in CTL mice expressing hM4Di, CNO significantly increased alcohol drinking (∼30%; p < 0.05) to levels similar to the CIE mice. The vHC-NAc pathway was targeted by infusing CNO into the NAc (3 or 10 µM/side) 30 min before testing. CNO activation of the pathway in mice expressing excitatory (hM3Dq) DREADDs selectively reduced consumption in CIE mice back to CTL levels (∼35-45%; p < 0.05) without affecting CTL alcohol intake. Lastly, activating the vHC-NAc pathway increased cFos expression and evoked significant glutamate release from the vHC terminals in the NAc. These data indicate that reduced activity of the vHC increases alcohol consumption and that targeted, increased activity of the vHC-NAc pathway attenuates excessive drinking associated with alcohol dependence. Thus, these findings indicate that the vHC and its glutamatergic projections to the NAc are involved in excessive alcohol drinking.

Análisis de pacientes con lesiones vertebrales por proyectil de arma de fuego según el retorno laboral / Analysis of patients with vertebral gunshot injuries according to return to work

Introducción: Las lesiones vertebrales por arma de fuego representan el 13-17% de las lesiones vertebrales traumáticas con presentación clínica variable. El objetivo de este estudio fue comparar las características demográficas y clínico-terapéuticas de pacientes que sufrieron lesiones vertebrales por arma de fuego en el contexto de accidentes laborales, según la posibilidad de retorno laboral. materiales y métodos: Estudio analítico, observacional y retrospectivo de pacientes con lesión vertebral por arma de fuego en accidentes de trabajo, entre enero de 2012 y marzo de 2022. Se registraron variables sociodemográficas y relacionadas con el siniestro, la atención inicial, la lesión vertebral, el tratamiento, la evolución y el retorno laboral. Resultados: Se evaluó a 22 pacientes (15 hombres y 7 mujeres; media de la edad 32.5 años). El 54% eran trabajadores de fuerzas de seguridad; no obstante, el 82% de los accidentes se había producido in itinere. El 90% tenía lesiones asociadas. Doce (55%) requirieron cirugía y 10 (45%), tratamiento conservador. El 81% sufrió complicaciones. Doce (54%) regresaron al trabajo, un tercio fue recalificado y 9 requirieron la baja laboral. Se halló una asociación estadística entre pacientes con baja laboral permanente y topografía torácica (p = 0,005), daño neurológico severo (p = 0,004), incidencia transfixiante o penetrante (p = 0,005), requerimiento de tratamiento psiquiátrico crónico (p = 0,012) y más días de incapacidad laboral temporaria (p = 0,001). Conclusión: La baja laboral permanente se asoció con lesiones torácicas, transfixiantes o penetrantes, compromiso neurológico severo y requerimiento de tratamiento psiquiátrico clínico-farmacológico crónico. Nivel de Evidencia: IV

Introduction: Firearm spinal injuries account for 13-17% of all traumatic spinal injuries, with varying clinical manifestations. The goal of this study was to examine the demographic and clinical-therapeutic characteristics of patients who suffered spinal injuries as a consequence of gunshots in the context of workplace incidents, based on how soon they could return to work. materials and methods: An analytic, observational, and retrospective study of patients with spinal injuries caused by firearms in workplace incidents between January 2012 and March 2022 was conducted. Variables associated with the incident, initial assessment, spinal injury, treatment, progression, and return to work were recorded. Results: Twenty-two individuals were evaluated (15 men and 7 women; mean age 32.5 years). 54% were law enforcement officers, yet 82% of the accidents happened on the job. 90% had associated injuries. Twelve (55%) required surgery, while ten (45%) required conservative treatment. 81% had complications. Twelve patients (54%) returned to work, one-third were requalified, and nine needed sick leave. Patients on permanent sick leave had a statistically significant relationship with chest topography (p = 0.005), severe neurological damage (p = 0.004), transfixing or penetrating injuries (p = 0.005), the need for chronic psychiatric treatment (p = 0.012), and more days of temporary incapacity for work (p = 0.001). Conclusion: In our series, permanent sick leave was associated with thoracic, transfixing, or penetrating injuries, severe neurological compromise, and the need for chronic clinical-pharmacological psychiatric treatment. Level of Evidence: IV

Effect of chronic intermittent ethanol vapor exposure on RNA content of brain-derived extracellular vesicles.

Extracellular vesicles (EVs) are important players in normal biological function and disease pathogenesis. Of the many biomolecules packaged into EVs, coding and noncoding RNA transcripts are of particular interest for their ability to significantly alter cellular and molecular processes. Here we investigate how chronic ethanol exposure impacts EV RNA cargo and the functional outcomes of these changes. Following chronic intermittent ethanol (CIE) vapor exposure, EVs were isolated from male and female C57BL/6J mouse brain. Total RNA from EVs was analyzed by lncRNA/mRNA microarray to survey changes in RNA cargo following vapor exposure. Differential expression analysis of microarray data revealed a number of lncRNA and mRNA types differentially expressed in CIE compared to control EVs. Weighted gene co-expression network analysis identified multiple male and female specific modules related to neuroinflammation, cell death, demyelination, and synapse organization. To functionally test these changes, whole-cell voltage-clamp recordings were used to assess synaptic transmission. Incubation of nucleus accumbens brain slices with EVs led to a reduction in spontaneous excitatory postsynaptic current amplitude, although no changes in synaptic transmission were observed between control and CIE EV administration. These results indicate that CIE vapor exposure significantly changes the RNA cargo of brain-derived EVs, which have the ability to impact neuronal function.

Predictive factors of pathological complete response after induction (ypT0N0M0) in non-small cell lung cancer and short-term outcomes: Results of the Spanish Group of Video-assisted Thoracic Surgery (GE-VATS).

INTRODUCTION: To analyze the predictors of pCR in NSCLC patients who underwent anatomical lung resection after induction therapy and to evaluate the postoperative results of these patients. METHODS: All patients prospectively registered in the database of the GE-VATS working group undergone anatomic lung resection by NSCLC after induction treatment and recruited between 12/20/2016 and 3/20/2018 were included in the study. The population was divided into two groups: patients who obtained a complete pathological response after induction (pCR) and patients who did not obtain a complete pathological response after induction (non-pCR). A multivariate analysis was performed using a binary logistic regression to determine the predictors of pCR and the postoperative results of patients were analyzed. RESULTS: Of the 241 patients analyzed, 36 patients (14.9%) achieved pCR. Predictive factors for pCR are male sex (OR: 2.814, 95% CI: 1.015-7.806), histology of squamous carcinoma (OR: 3.065, 95% CI: 1.233-7.619) or other than adenocarcinoma (OR: 5.788, 95% CI: 1.878-17.733) and induction therapy that includes radiation therapy (OR: 4.096, 95% CI: 1.785-9.401) and targeted therapies (OR: 7.625, 95% CI: 2.147-27.077). Prevalence of postoperative pulmonary complications was higher in patients treated with neoadjuvant chemo-radiotherapy (p = 0.032). CONCLUSIONS: Male sex, histology of squamous carcinoma or other than ADC, and induction therapy that includes radiotherapy or targeted therapy are positive predictors for obtaining pCR. Induction chemo-radiotherapy is associated with a higher risk of postoperative pulmonary complications.

Dynorphin/Kappa Opioid Receptor Activity Within the Extended Amygdala Contributes to Stress-Enhanced Alcohol Drinking in Mice.

BACKGROUND: While there is high comorbidity of stress-related disorders and alcohol use disorder, few effective treatments are available and elucidating underlying neurobiological mechanisms has been hampered by a general lack of reliable animal models. Here, we use a novel mouse model demonstrating robust and reproducible stress-enhanced alcohol drinking to examine the role of dynorphin/kappa opioid receptor (DYN/KOR) activity within the extended amygdala in mediating this stress-alcohol interaction. METHODS: Mice received repeated weekly cycles of chronic intermittent ethanol exposure alternating with weekly drinking sessions ± forced swim stress exposure. Pdyn messenger RNA expression was measured in the central amygdala (CeA), and DYN-expressing CeA neurons were then targeted for chemogenetic inhibition. Finally, a KOR antagonist was microinjected into the CeA or bed nucleus of the stria terminalis to examine the role of KOR signaling in promoting stress-enhanced drinking. RESULTS: Stress (forced swim stress) selectively increased alcohol drinking in mice with a history of chronic intermittent ethanol exposure, and this was accompanied by elevated Pdyn messenger RNA levels in the CeA. Targeted chemogenetic silencing of DYN-expressing CeA neurons blocked stress-enhanced drinking, and KOR antagonism in the CeA or bed nucleus of the stria terminalis significantly reduced stress-induced elevated alcohol consumption without altering moderate intake in control mice. CONCLUSIONS: Using a novel and robust model of stress-enhanced alcohol drinking, a significant role for DYN/KOR activity within extended amygdala circuitry in mediating this effect was demonstrated, thereby providing further evidence that the DYN/KOR system may be a valuable target in the development of more effective treatments for individuals presenting with comorbidity of stress-related disorders and alcohol use disorder.

Assessing negative affect in mice during abstinence from alcohol drinking: Limitations and future challenges.

Alcohol use disorder (AUD) is frequently comorbid with mood disorders, and these co-occurring neuropsychiatric disorders contribute to the development and maintenance of alcohol dependence and relapse. In preclinical models, mice chronically exposed to alcohol display anxiety-like and depressive-like behaviors during acute withdrawal and protracted abstinence. However, in total, results from studies using voluntary alcohol-drinking paradigms show variable behavioral outcomes in assays measuring negative affective behaviors. Thus, the main objective of this review is to summarize the literature on the variability of negative affective behaviors in mice after chronic alcohol exposure. We compare the behavioral phenotypes that emerge during abstinence across different exposure models, including models of alcohol and stress interactions. The complicated outcomes from these studies highlight the difficulties of assessing negative affective behaviors in mouse models designed for the study of AUD. We discuss new behavioral assays, comprehensive platforms, and unbiased machine-learning algorithms as promising approaches to better understand the interaction between alcohol and negative affect in mice. New data-driven approaches in the understanding of mouse behavior hold promise for improving the identification of mechanisms, cell subtypes, and neurocircuits that mediate negative affect. In turn, improving our understanding of the neurobehavioral basis of alcohol-associated negative affect will provide a platform to test hypotheses in mouse models that aim to improve the development of more effective strategies for treating individuals with AUD and co-occurring mood disorders.

The histone methyltransferase G9a mediates stress-regulated alcohol drinking.

The epigenetic enzyme G9a is a histone methyltransferase that dimethylates lysine 9 on histone H3 (H3K9me2), and in the adult nucleus accumbens (NAc), G9a regulates multiple behaviors associated with substance use disorder. We show here that chronic intermittent ethanol (CIE) exposure in male mice reduced both G9a and H3K9me2 levels in the adult NAc, but not dorsal striatum. Viral-mediated reduction of G9a in the NAc had no effects on baseline volitional ethanol drinking or escalated alcohol drinking produced by CIE exposure; however, NAc G9a was required for stress-regulated changes in ethanol drinking, including potentiated alcohol drinking produced by activation of the kappa-opioid receptor. In addition, we observed that chronic systemic administration of a G9a inhibitor, UNC0642, also blocked stress-potentiated alcohol drinking. Together, our findings suggest that chronic alcohol use, similar to other abused substances, produces a NAc-selective reduction in G9a levels that serves to limit stress-regulated alcohol drinking. Moreover, our findings suggest that pharmacological inhibition of G9a might provide a novel therapeutic approach to treat stress-induced alcohol drinking, which is a major trigger of relapse in individuals suffering from AUD.