Pedro Araos

Plasma profile of pro-inflammatory cytokines and chemokines in cocaine users under outpatient treatment: influence of cocaine symptom severity and psychiatric co-morbidity.

The treatment for cocaine use constitutes a clinical challenge because of the lack of appropriate therapies and the high rate of relapse. Recent evidence indicates that the immune system might be involved in the pathogenesis of cocaine addiction and its co‐morbid psychiatric disorders. This work examined the plasma pro‐inflammatory cytokine and chemokine profile in abstinent cocaine users (n = 82) who sought outpatient cocaine treatment and age/sex/body mass‐matched controls (n = 65). Participants were assessed with the diagnostic interview Psychiatric Research Interview for Substance and Mental Diseases according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM‐IV‐TR). Tumor necrosis factor‐alpha, chemokine (C‐C motif) ligand 2/monocyte chemotactic protein‐1 and chemokine (C‐X‐C motif) ligand 12 (CXCL12)/stromal cell‐derived factor‐1 (SDF‐1) were decreased in cocaine users, although all cytokines were identified as predictors of a lifetime pathological use of cocaine. Interleukin‐1 beta (IL‐1β), chemokine (C‐X3‐C motif) ligand 1 (CX3CL1)/fractalkine and CXCL12/SDF‐1 positively correlated with the cocaine symptom severity when using the DSM‐IV‐TR criteria for cocaine abuse/dependence. These cytokines allowed the categorization of the outpatients into subgroups according to severity, identifying a subgroup of severe cocaine users (9–11 criteria) with increased prevalence of co‐morbid psychiatric disorders [mood (54%), anxiety (32%), psychotic (30%) and personality (60%) disorders]. IL‐1β was observed to be increased in users with such psychiatric disorders relative to those users with no diagnosis. In addition to these clinical data, studies in mice demonstrated that plasma IL‐1β, CX3CL1 and CXCL12 were also affected after acute and chronic cocaine administration, providing a preclinical model for further research. In conclusion, cocaine exposure modifies the circulating levels of pro‐inflammatory mediators. Plasma cytokine/chemokine monitoring could improve the stratification of cocaine consumers seeking treatment and thus facilitate the application of appropriate interventions, including management of heightened risk of psychiatric co‐morbidity. Further research is necessary to elucidate the role of the immune system in the etiology of cocaine addiction.

Oleoylethanolamide dose-dependently attenuates cocaine-induced behaviours through a PPARα receptor-independent mechanism.

Oleoylethanolamide (OEA) is an acylethanolamide that acts as an agonist of nuclear peroxisome proliferator‐activated receptor alpha (PPARα) to exert their biological functions, which include the regulation of appetite and metabolism. Increasing evidence also suggests that OEA may participate in the control of reward‐related behaviours. However, direct experimental evidence for the role of the OEA‐PPARα receptor interaction in drug‐mediated behaviours, such as cocaine‐induced behavioural phenotypes, is lacking. The present study explored the role of OEA and its receptor PPARα on the psychomotor and rewarding responsiveness to cocaine using behavioural tests indicative of core components of addiction. We found that acute administration of OEA (1, 5 or 20 mg/kg, i.p.) reduced spontaneous locomotor activity and attenuated psychomotor activation induced by cocaine (20 mg/kg) in C57Bl/6 mice. However, PPARα receptor knockout mice showed normal sensitization, although OEA was capable of reducing behavioural sensitization with fewer efficacies. Furthermore, conditioned place preference and reinstatement to cocaine were intact in these mice. Our results indicate that PPARα receptor does not play a critical, if any, role in mediating short‐ and long‐term psychomotor and rewarding responsiveness to cocaine. However, further research is needed for the identification of the targets of OEA for its inhibitory action on cocaine‐mediated responses.

Hyperactivity induced by the dopamine D2/D3 receptor agonist quinpirole is attenuated by inhibitors of endocannabinoid degradation in mice

The present study was designed to investigate the effect of pharmacological inhibition of endocannabinoid degradation on behavioural actions of the dopamine D2/D3 receptor agonist quinpirole in male C57Bl/6J mice. In addition, we studied the effects of endocannabinoid degradation inhibition on both cocaine-induced psychomotor activation and behavioural sensitization. We analysed the effects of inhibition of the two main endocannabinoid degradation enzymes: fatty acid amide hydrolase (FAAH), using inhibitor URB597 (1 mg/kg); monoacylglycerol lipase (MAGL), using inhibitor URB602 (10 mg/kg). Administration of quinpirole (1 mg/kg) caused a temporal biphasic response characterized by a first phase of immobility (0-50 min), followed by enhanced locomotion (next 70 min) that was associated with the introduction of stereotyped behaviours (stereotyped jumping and rearing). Pretreatment with both endocannabinoid degradation inhibitors did not affect the hypoactivity actions of quinpirole. However, this pretreatment resulted in a marked decrease in quinpirole-induced locomotion and stereotyped behaviours. Administration of FAAH or MAGL inhibitors did not attenuate the acute effects of cocaine. Furthermore, these inhibitors did not impair the acquisition of cocaine-induced behavioural sensitization or the expression of cocaine-induced conditioned locomotion. Only MAGL inhibition attenuated the expression of an already acquired cocaine-induced behavioural sensitization. These results suggest that pharmacological inhibition of endocannabinoid degradation might exert a negative feedback on D2/D3 receptor-mediated hyperactivity. This finding might be relevant for therapeutic approaches for either psychomotor disorders (dyskinesia, corea) or disorganized behaviours associated with dopamine-mediated hyperactivity.

Comorbilidad psicopatológica en consumidores de cocaína en tratamiento ambulatorio

Cocaine addiction is a growing health problem and among its complications highlights the high prevalence of mental disorders co-occurring with abuse and dependence. This psychopathological comorbidity varies according to the time of consumption and the age of the patient. Early detection of psychopathological disorders associated with drug consumption is necessary to optimize health care and to improve the prognosis. The main aim of the present study was to estimate the prevalence and characteristics of psychopathological comorbidity in a population of subjects seeking outpatient treatment for cocaine use. We recruited 110 subjects using cocaine by nasal insufflations evaluated with the PRISM (Psychiatric Research Interview for Substance and Mental Disorders), a semi-structured diagnostic interview that differentiates primary mental disorders from those induced by the drug. This population presented 86.4% male and had a mean age of 36.5. They displayed a pathological use of cocaine of 7 years and the presence of psychopathology was associated with a higher number of DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders- IV-TR) criteria for substance dependence. The lifetime prevalence of some psychopathological comorbidity was 61.8%, highlighting mood disorders (34.5%), followed by anxiety disorders (22.7%) and psychotic disorders (15.5%). About 20% showed antisocial personality disorder and 21% borderline personality disorder. From among mood and psychotic disorders, the induced disorders were more frequent, while the primary disorders were more prevalent in anxiety.

Sex differences in psychiatric comorbidity and plasma biomarkers for cocaine addiction in abstinent cocaine-addicted subjects in outpatient settings

There are sex differences in the progression of drug addiction, relapse, and response to therapies. Because biological factors participate in these differences, they should be considered when using biomarkers for addiction. In the current study, we evaluated the sex differences in psychiatric comorbidity and the concentrations of plasma mediators that have been reported to be affected by cocaine. Fifty-five abstinent cocaine-addicted subjects diagnosed with lifetime cocaine use disorders (40 men and 15 women) and 73 healthy controls (48 men and 25 women) were clinically assessed with the diagnostic interview “Psychiatric Research Interview for Substance and Mental Disorders.” Plasma concentrations of chemokines, cytokines, N-acyl-ethanolamines, and 2-acyl-glycerols were analyzed according to history of cocaine addiction and sex, controlling for covariates age and body mass index (BMI). Relationships between these concentrations and variables related to cocaine addiction were also analyzed in addicted subjects. The results showed that the concentrations of chemokine (C-C motif) ligand 2/monocyte chemotactic protein-1 (CCL2/MCP-1) and chemokine (C-X-C motif) ligand 12/stromal cell-derived factor-1 (CXCL12/SDF-1) were only affected by history of cocaine addiction. The plasma concentrations of interleukin 1-beta (IL-1β), IL-6, IL-10, and tumor necrosis factor-alpha (TNFα) were affected by history of cocaine addiction and sex. In fact, whereas cytokine concentrations were higher in control women relative to men, these concentrations were reduced in cocaine-addicted women without changes in addicted men. Regarding fatty acid derivatives, history of cocaine addiction had a main effect on the concentration of each acyl derivative, whereas N-acyl-ethanolamines were increased overall in the cocaine group, 2-acyl-glycerols were decreased. Interestingly, N-palmitoleoyl-ethanolamine (POEA) was only increased in cocaine-addicted women. The covariate BMI had a significant effect on POEA and N-arachidonoyl-ethanolamine concentrations. Regarding psychiatric comorbidity in the cocaine group, women had lower incidence rates of comorbid substance use disorders than did men. For example, alcohol use disorders were found in 80% of men and 40% of women. In contrast, the addicted women had increased prevalences of comorbid psychiatric disorders (i.e., mood, anxiety, and psychosis disorders). Additionally, cocaine-addicted subjects showed a relationship between the concentrations of N-stearoyl-ethanolamine and 2-linoleoyl-glycerol and diagnosis of psychiatric comorbidity. These results demonstrate the existence of a sex influence on plasma biomarkers for cocaine addiction and on the presence of comorbid psychopathologies for clinical purposes.

Plasma Concentrations of BDNF and IGF-1 in Abstinent Cocaine Users with High Prevalence of Substance Use Disorders: Relationship to Psychiatric Comorbidity

Recent studies have identified biomarkers related to the severity and pathogenesis of cocaine addiction and common comorbid psychiatric disorders. Monitoring these plasma mediators may improve the stratification of cocaine users seeking treatment. Because the neurotrophic factors are involved in neural plasticity, neurogenesis and neuronal survival, we have determined plasma concentrations of brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1) and IGF-1 binding protein 3 (IGFBP-3) in a cross-sectional study with abstinent cocaine users who sought outpatient treatment for cocaine (n = 100) and age/body mass matched controls (n = 85). Participants were assessed with the diagnostic interview ‘Psychiatric Research Interview for Substance and Mental Disorders’. Plasma concentrations of these peptides were not different in cocaine users and controls. They were not associated with length of abstinence, duration of cocaine use or cocaine symptom severity. The pathological use of cocaine did not influence the association of IGF-1 with age observed in healthy subjects, but the correlation between IGF-1 and IGFBP-3 was not significantly detected. Correlation analyses were performed between these peptides and other molecules sensitive to addiction: BDNF concentrations were not associated with inflammatory mediators, lipid derivatives or IGF-1 in cocaine users, but correlated with chemokines (fractalkine/CX3CL1 and SDF-1/CXCL12) and N-acyl-ethanolamines (N-palmitoyl-, N-oleoyl-, N-arachidonoyl-, N-linoleoyl- and N-dihomo-γ-linolenoyl-ethanolamine) in controls; IGF-1 concentrations only showed association with IGFBP-3 concentrations in controls; and IGFBP-3 was only correlated with N-stearoyl-ethanolamine concentrations in cocaine users. Multiple substance use disorders and life-time comorbid psychopathologies were common in abstinent cocaine users. Interestingly, plasma BDNF concentrations were exclusively found to be decreased in users diagnosed with both primary and cocaine-induced disorders for mood and anxiety disorders. In summary, BDNF, IGF-1 and IGFBP-3 were not affected by a history of pathological use of cocaine supported by the absence of associations with other molecules sensitive to cocaine addiction. However, BDNF was affected by comorbid mood disorders. Further research is necessary to elucidate the role of BDNF and IGF-1 in the transition to cocaine addiction and associated psychiatric comorbidity.

Lipid Transmitter Signaling as a New Target for Treatment of Cocaine Addiction: New Roles for Acylethanolamides and Lysophosphatidic Acid

This review analyzes the roles of lipid transmitters, especially those derived from the cleavage of membrane phospholipids, in cocaine-associated behaviors. These lipid signals are important modulators of information processing in the brain, affecting transmitter release, neural plasticity, synaptogenesis, neurogenesis, and cellular energetics. This broad range of actions makes them suitable targets for pharmaceutical development of cocaine addiction therapies because they participate in the main cellular processes underlying the neuroadaptations associated with chronic use of this psychostimulant. The main lipid transmitters reviewed here include a) acylethanolamides and acylglycerols acting on cannabinoid receptors, such as anandamide and 2-arachidonoylglycerol; b) acylethanolamides that do not act on cannabinoid receptors, such as oleoylethanolamide; c) eicosanoids derived from arachidonic acid, including prostaglandins; and d) lysophosphatidic acid, focusing on the role of its LPA-1 receptor. Direct experimental evidence for the significance of these lipids in cocaine-related behaviors is presented and discussed. Additionally, the roles for both their biosynthesis and degradation pathways, as well as the participation of their receptors, are examined. Overall, lipid transmitter signaling can offer new targets for the development of therapies for cocaine addiction.

Plasma Chemokines in Patients with Alcohol Use Disorders: Association of CCL11 (Eotaxin-1) with Psychiatric Comorbidity.

Recent studies have linked changes in peripheral chemokine concentrations to the presence of both addictive behaviors and psychiatric disorders. The present study further explore this link by analyzing the potential association of psychiatry comorbidity with alterations in the concentrations of circulating plasma chemokine in patients of both sexes diagnosed with alcohol use disorders (AUD). To this end, 85 abstinent subjects with AUD from an outpatient setting and 55 healthy subjects were evaluated for substance and mental disorders. Plasma samples were obtained to quantify chemokine concentrations [C–C motif (CC), C–X–C motif (CXC), and C–X3–C motif (CX3C) chemokines]. Abstinent AUD patients displayed a high prevalence of comorbid mental disorders (72%) and other substance use disorders (45%). Plasma concentrations of chemokines CXCL12/stromal cell-derived factor-1 (p < 0.001) and CX3CL1/fractalkine (p < 0.05) were lower in AUD patients compared to controls, whereas CCL11/eotaxin-1 concentrations were strongly decreased in female AUD patients (p < 0.001). In the alcohol group, CXCL8 concentrations were increased in patients with liver and pancreas diseases and there was a significant correlation to aspartate transaminase (r = +0.456, p < 0.001) and gamma-glutamyltransferase (r = +0.647, p < 0.001). Focusing on comorbid psychiatric disorders, we distinguish between patients with additional mental disorders (N = 61) and other substance use disorders (N = 38). Only CCL11 concentrations were found to be altered in AUD patients diagnosed with mental disorders (p < 0.01) with a strong main effect of sex. Thus, patients with mood disorders (N = 42) and/or anxiety (N = 16) had lower CCL11 concentrations than non-comorbid patients being more evident in women. The alcohol-induced alterations in circulating chemokines were also explored in preclinical models of alcohol use with male Wistar rats. Rats exposed to repeated ethanol (3 g/kg, gavage) had lower CXCL12 (p < 0.01) concentrations and higher CCL11 concentrations (p < 0.001) relative to vehicle-treated rats. Additionally, the increased CCL11 concentrations in rats exposed to ethanol were enhanced by the prior exposure to restraint stress (p < 0.01). Concordantly, acute ethanol exposure induced changes in CXCL12, CX3CL1, and CCL11 in the same direction to repeated exposure. These results clearly indicate a contribution of specific chemokines to the phenotype of AUD and a strong effect of sex, revealing a link of CCL11 to alcohol and anxiety/stress.

Comorbilidad psiquiátrica y valores plasmáticos de 2-acilgliceroles en consumidores de alcohol en tratamiento ambulatorio. Análisis de las diferencias de género

Alcohol addiction is associated with high psychiatric comorbidity. Objective stratification of patients is necessary to optimize care and improve prognosis. The present study is designed to gain insights into this challenge by addressing the following objectives: a) to estimate the prevalence of psychiatric comorbidities in a sample of outpatients seeking treatment for alcohol use disorder, b) to describe the existence of gender differences and c) to validate 2-acyl-glycerols as biomarkers of alcohol use disorder and/or psychiatric comorbidity. One hundred and sixty-two patients were recruited and evaluated with the semi-structured interview PRISM. The presence of psychopathology was associated with a greater number of criteria for alcohol abuse and dependence according to DSM-IV-TR. We found gender differences in psychiatric comorbidity, e.g., mood disorder, as well as in comorbid substance use disorders. The prevalence of lifetime psychiatric comorbidity was 68.5%, with mood disorders the most frequent (37%), followed by attention deficit disorder (24.7%) and anxiety disorders (17.9%). Substance-induced disorders were more frequent in mood and psychotic disorders, whereas the primary disorders were more prevalent in patients with comorbid anxiety disorders. We found that 2-acyl-glycerols were significantly decreased in comorbid anxiety disorders in alcohol dependent patients in the last year, which makes them a potential biomarker for this psychopathological condition.

Plasma concentrations of oleoylethanolamide and other acylethanolamides are altered in alcohol-dependent patients: effect of length of abstinence

Acylethanolamides are a family of endogenous lipid mediators that are involved in physiological and behavioral processes associated with addiction. Recently, oleoylethanolamide (OEA) has been reported to reduce alcohol intake and relapse in rodents but the contribution of OEA and other acylethanolamides in alcohol addiction in humans is unknown. The present study is aimed to characterize the plasma acylethanolamides in alcohol dependence. Seventy‐nine abstinent alcohol‐dependent subjects (27 women) recruited from outpatient treatment programs and age‐/sex‐/body mass‐matched healthy volunteers (28 women) were clinically assessed with the diagnostic interview PRISM according to the DSM‐IV‐TR after blood extraction for quantification of acylethanolamide concentrations in the plasma. Our results indicate that all acylethanolamides were significantly increased in alcohol‐dependent patients compared with control subjects (p < 0.001). A logistic model based on these acylethanolamides was developed to distinguish alcohol‐dependent patients from controls and included OEA, arachidonoylethanolamide (AEA) and docosatetraenoylethanolamide (DEA), providing a high discriminatory power according to area under the curve [AUC = 0.92 (95%CI: 0.87–0.96), p < 0.001]. Additionally, we found a significant effect of the duration of alcohol abstinence on the concentrations of OEA, AEA and DEA using a regression model (p < 0.05, p < 0.01 and p < 0.001, respectively), which was confirmed by a negative correlation (rho = −0.31, −0.40 and −0.44, respectively). However, acylethanolamides were not influenced by the addiction alcohol severity, duration of problematic alcohol use or diagnosis of psychiatric comorbidity. Our results support the preclinical studies and suggest that OEA, AEA and DEA are altered in alcohol‐dependence during abstinence and that might act as potential markers for predicting length of alcohol abstinence.