Increase in brain-derived neurotrophic factor expression in early crack cocaine withdrawal

Exploring peripheral biomarkers in psychostimulant use: A systematic review on neurotrophins, stress-related hormones, oxidative stress molecules and genetic factors

BACKGROUND

This systematic review aims to comprehensively explore the impact of psychostimulant substances on neurotrophic and inflammatory pathways, including brain-derived neurotrophic factor (BDNF), pro-BDNF, cortisol, dehydroepiandrosterone sulfate (DHEAS), thiobarbituric acid reactive substances (TBARS), interleukins, and the role of genetic factors. The study seeks to address existing gaps in the literature by providing a thorough evaluation of neurotrophic and inflammatory system alterations associated with different stages of psychostimulant dependence for a more nuanced understanding of substance use disorder (SUD) neurobiology.

METHODS

A systematic review was conducted in PubMed, Scopus, and Web of Science databases following the PRISMA guidelines. The research encompasses 50 studies with a participant pool totaling 6792 individuals using psychostimulant substances.

RESULTS

Key findings include diverse impacts of cocaine on BDNF levels, mainly consisting of their significant increase during withdrawal. In contrast, NGF showed an opposite behavior, reducing during withdrawal. Cortisol and DHEAS levels exhibited relevant increases after psychostimulant use, while TBARS showed conflicting results. Genetic investigations predominantly focused on the Val66Met polymorphism of the BDNF gene, revealing associations with susceptibility to stimulant addiction.

CONCLUSIONS

Neurotrophins and inflammatory molecules play a significant role in the pathophysiological mechanisms following psychostimulant use. A better understanding of their complex interplay could aid clinicians in identifying biomarkers of different disease stages. Moreover, clinical interventions designed to interfere with neurotrophic and inflammatory pathways could possibly lead to craving-modulatory strategies and reduce pathological neuronal and systemic consequences of psychostimulant use.

Enhanced peripheral levels of BDNF and proBDNF: elucidating neurotrophin dynamics in cocaine use disorder

Brain-derived neurotrophic factor (BDNF) and its precursor, proBDNF, are known to significantly contribute to brain homeostasis, neuroplasticity, and neuronal remodeling. Although these neurotrophins are thought to have opposing roles, both play a critical part in shaping long-lasting behavioral changes following substance use. In this context, our study sought to explore the implications of these neurotrophins in the pathophysiology of cocaine use disorder (CUD). We conducted a case-control study, which included 28 individuals seeking treatment for CUD and 38 matched healthy participants. We measured peripheral neurotrophin concentrations via an enzyme-linked immunosorbent assay. Additionally, all participants were screened for cocaine-associated pathways (e.g., cocaine intake, craving intensity), along with associated psychopathological data. Our findings highlighted an increased concentration of BDNF and proBDNF in CUD individuals when compared to healthy controls (BDNF: 18092.80 ± 6844.62 vs. 11334.42 ± 5061.85 pg/ml, p < 0.001; proBDNF: 87.03 ± 33.23 vs. 55.70 ± 23.26 ng/ml, p < 0.001). We further corroborated the relationship between neurotrophin levels and CUD using a linear regression model. Nevertheless, there was no significant difference in the proBDNF to BDNF ratio between the two groups. Interestingly, our study also demonstrated the influence of factors like usage of psychotropic medications, history of psychiatric hospitalizations, and psychiatric diagnoses on neurotrophin dynamics. In conclusion, our study underscores the significance of neurotrophin fluctuations in CUD. The observed increase in BDNF and proBDNF levels could play a pivotal role in driving craving and relapse risk. Thus, a nuanced understanding of these neurobiological underpinnings in CUD might contribute to the development of more targeted and effective therapeutic strategies.

Brain-derived neurotrophic factor serum levels as a candidate biomarker for withdrawal in crack heroin dependence

BACKGROUND

Crack heroin is a novel opiate derivative with highly addictive properties and unfamiliar health consequences. It causes a variety of brain dysfunctions that are mediated by neurochemical alterations and abnormal neuroplasticity. Brain-derived neurotrophic factor (BDNF) is a widely recognized biological marker implicated in the neuropathology of substance use during substance use disorder and withdrawal. Its involvement can significantly contribute to the severity of withdrawal symptoms. Hence, this study aimed to evaluate BDNF levels in crack heroin users before and after withdrawal.

METHODS

In this cross-sectional study, 148 male participants were recruited and divided into two groups: persons with crack heroin use disorder (n = 74) and the controls (n = 74). The BDNF serum levels were measured in both crack heroin users and control groups upon hospitalization and again after twenty-one days of withdrawal using the enzyme-linked immunosorbent assay.

RESULTS

The results demonstrated that BDNF levels in persons with crack heroin use disorder upon admission were significantly lower than the levels observed upon discharge and in the control group (p < 0.05). Additionally, a significant difference in BDNF levels was found between persons with crack heroin use disorder at admission and discharge (p = 0.038). Furthermore, BDNF levels showed an inverse correlation with the daily dose of substance use (r= -0.420, p = 0.03) and the duration of crack heroin use (r= -0.235, p = 0.001).

CONCLUSIONS

A progressive increment in BDNF levels during early detoxification is associated with the daily amount of substance use and the duration of substance use. Our findings suggest that changes in BDNF serum levels during crack heroin use disorder and withdrawal could serve as potential biomarkers for assessing the intensity of withdrawal symptoms and substance use-related behaviors.

Peripheral neurotrophin levels during controlled crack/cocaine abstinence: a systematic review and meta-analysis

Cocaine/crack abstinence periods have higher risk of relapse. Abstinence as initial part of the recovery process is affected by learning and memory changes that could preserve the addictive cycle. To further understand how the interruption of cocaine/crack consumption affects neurotrophin level we performed the present systematic review and meta-analysis following the PRISMA statement (number CRD42019121643). The search formula was conducted in PubMed, Web of Science, Embase, ScienceDirect, and Google Scholar databases. The inclusion criterion was cocaine use disorder in 18 to 60-year-old people, measuring at least one neurotrophin in blood before and after a controlled abstinence period. Studies without pre-post design were excluded. Five investigations had nine different reports, four of them were subjected to a meta-analysis (n = 146). GRADE risk of bias method was followed. Individual studies reported increased peripheral brain derived neurotrophic factor (BDNF) after abstinence, evidence pooled by Hedge's g showed no significant change in BDNF after abstinence. Relevant heterogeneity in the length of the abstinence period (12-32 days), last cocaine/crack consumption monitoring and blood processing were detected that could help to explain non-significant results. Further improved methods are suggested, and a potential BDNF augmentation hypothesis is proposed that, if true, would help to understand initial abstinence as a re-adaptation period influenced by neurotrophins such as the BDNF.

From a Cycle to a Period: The Potential Role of BDNF as Plasticity and Phase-Specific Biomarker in Cocaine Use Disorder

Cocaine Use Disorder (CUD) is one of the diseases with the greatest social and health impact, due to the high cost of rehabilitation management and the high risk of dangerous behavior and relapse. This pathology frequently leads to unsuccessful attempts to interrupt the consumption, resulting in relapses and a vicious cycle of binge/intoxication, withdrawal/negative affect, and preoccupation/ anticipation (craving). The alternation of these phases in addiction was well illustrated by Koob and colleagues in the so-called "addictive cycle", which nowadays represents a landmark in the addiction field. Recently, there has been a surge of interest in the worldwide literature for biomarkers that might explain the different stages of addiction, and one of the most studied biomarkers is, without a doubt, Brain-derived Neurotrophic Factor (BDNF). In this perspective article, we discuss the potential role of BDNF as biomarker of the CUD phases described in the "Addictive Cycle", speculating about the close relationship between BDNF fluctuations and the clinical course of CUD. We also discuss BDNF's potential role as "staging" biomarker, predicting the progression of the disease. Finding valuable biomarkers of CUD severity and disease stage could shift clinicians' focus away from behavioral symptomatic treatment and toward a novel brain-based approach, allowing for the development of more effective and targeted therapeutic strategies, thus determining major benefits for CUD patients.

Biomarkers of Relapse in Cocaine Use Disorder: A Narrative Review

Introduction: Cocaine use disorder is a chronic disease with severe consequences and a high relapse rate. There is a critical need to explore the factors influencing relapse in order to achieve more efficient treatment outcomes. Furthermore, there is a great need for easy-to-measure, repeatable, and valid biomarkers that can predict treatment response or relapse. Methods: We reviewed the available literature on the Pubmed database concerning the biomarkers associated with relapse in CUD, including central nervous system-derived, genetic, immune, oxidative stress, and “other” biomarkers. Results: Fifty-one articles were included in our analysis. Twenty-five imaging brain anatomic and function assessment studies, mostly using fMRI, examined the role of several structures such as the striatum activity in abstinence prediction. There were fewer studies assessing the use of neuropsychological factors, neurotrophins, or genetic/genomic factors, immune system, or oxidative stress measures to predict abstinence. Conclusion: Several biomarkers have been shown to have predictive value. Prospective studies using combined multimodal assessments are now warranted.

Impact of sleep disorders and disease duration on neurotrophins levels in cocaine use disorder

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) and its precursor proBDNF contribute to brain plasticity and neuronal remodeling. Recently, the ratio between proBDNF and BDNF (RpB) has been proposed as a possible marker in major psychiatric disorders. Convergent lines of evidence suggest neurotrophins alterations could be involved into the pathophysiology of Cocaine Use Disorder (CUD) and insomnia. The aims of the present study are to evaluate the correlations between neurotrophins levels, insomnia and clinical features among CUD patients.

MATERIALS AND METHODS

Subjects with a moderate to severe CUD were recruited. ProBDNF, BDNF and consequently RpB values were analyzed using ELISA technique. Insomnia severity index (ISI) scale was used to assess the severity of insomnia. Sociodemographic characteristics and CUD habits (e.g., years of cocaine use) were also collected.

RESULTS

Twenty-four subjects (mean age 39.3 ± 6.7 years) were recruited. Correlation analysis showed that lower values of RpB were associated with higher ISI score (r = -0.469; p = 0.021), longer history of cocaine use (r = -0.584, p = 0.022) and higher amount of cocaine used (r = -0.655, p = 0.004).

DISCUSSION

These preliminary findings may offer a novel insight on neurobiological alterations sustaining cocaine use. Lower RpB, as observed both in high insomnia levels and in chronic cocaine use, could induce a neuroprotective state as a synaptic homeostatic response to chronic damage. These findings also highlight the important role of neurotrophins balance on neurobiological alterations induced by cocaine misuse and insomnia, suggesting that RpB could be considered as a marker of neurotrophic and metabolic state of neural tissue.

Association between childhood trauma, parental bonding and antisocial personality disorder in adulthood: A machine learning approach

Childhood trauma (CT) and parental bonding (PB) have been correlated with later antisocial personality disorder (ASPD). Aiming to better understand this complex interaction we analyzed the data from a cross-sectional study that evaluated 346 male inpatient cocaine users, using both traditional statistical analysis and machine learning (ML) approaches. Childhood Trauma Questionnaire (CTQ), Parental Bonding Instrument (PBI), and Mini International Neuropsychiatric Interview (MINI) were applied. We found a markedly higher prevalence of mental illness in the ASPD group. The ML method and the traditional analysis showed that emotional and physical abuse were the factors with the strongest relationship with ASPD. Also, there were discrepancies between the findings of both methods regarding physical neglect and paternal care. Although this study does not allow definitive answers in this matter, we do propose that these two methods can aid in better comprehending how multiple variables interact with each other in the development of psychological disorders.

Behavioral and neurobiological alterations induced by chronic use of crack cocaine

Crack cocaine is the crystal form of cocaine and can be smoked, and rapidly absorbed, and, in part for this reason, is potently addictive. It is hypothesized that crack cocaine is able to induce important changes in different tissues and organs, and thus dramatically alter behavior. Nevertheless, which alterations in the central nervous system are related to its frequent use is still a matter of discussion. The present study is a literature review of articles published between the years 2008 and 2018 on the theme 'crack cocaine and brain' available in PUBMED, MEDLINE, EMBASE, and Google scholar databases. The results show that the use of crack cocaine induces important behavioral, neuroanatomical, and biochemical alterations. The main behavioral sequelae include cognitive and emotional changes, such as increased anxiety and depressive symptoms, attention and memory deficits, and hyperactivity. Among the neurobiological alterations are reductions in the activity of the prefrontal, anterior cingulate cortex, and nucleus accumbens. Molecular changes include decreases in neurotrophic factors and increases in oxidative stress and inflammatory cytokines, which may be responsible for the morphological alterations observed. It is also hypothesized that these neurobiological changes might explain the emotional and cognitive dysfunctions experienced by crack cocaine addicts.

Effects of childhood trauma on BDNF and TBARS during crack-cocaine withdrawal

Objective:

To evaluate the association between childhood trauma (CT) and serum levels of brain-derived neurotrophic factor (BDNF) and thiobarbituric acid-reactive substances (TBARS) during crack-cocaine withdrawal.

Method:

Thirty-three male crack-cocaine users were recruited at admission to a public addiction treatment unit. Serum BDNF and TBARS levels were evaluated at intake and discharge. Information about drug use was assessed by the Addiction Severity Index-6th Version (ASI-6); CT was reported throughout the Childhood Trauma Questionnaire (CTQ). CTQ scores were calculated based on a latent analysis model that divided the sample into low-, medium-, and high-level trauma groups.

Results:

There was a significant increase in BDNF levels from admission to discharge, which did not differ across CT subgroups. For TBARS levels, we found a significant time vs. trauma interaction (F_2,28 = 6.357, p = 0.005,η_p² = 0.312). In participants with low trauma level, TBARS decreased, while in those with a high trauma level, TBARS increased during early withdrawal.

Conclusion:

TBARS levels showed opposite patterns of change in crack-cocaine withdrawal according to baseline CT. These results suggest that CT could be associated with more severe neurological impairment during withdrawal.

Female crack cocaine users under treatment at therapeutic communities in southern Brazil: characteristics, pattern of consumption, and psychiatric comorbidities

OBJECTIVE

To explore and describe sociodemographic characteristics, crack consumption patterns, and psychiatric comorbidities of female crack users receiving treatment at therapeutic communities.

METHODS

This was a cross-sectional, descriptive, quantitative study. Forty-six women who abstained from crack use were assessed using a sociodemographic questionnaire, the Mini-Mental State Examination (MMSE), the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I), and a profile of crack use questionnaire. Descriptive statistical analyses were conducted.

RESULTS

Participants had a mean age of 31.02 years (standard deviation [SD] = 7.73), most were single (76.1%), white (67.4%) and had complete or incomplete elementary education (43.5%). Before treatment, 65.2% of the women reported using crack every day; 46.3% smoked between 10 to 30 crack rocks per week. Mean treatment time was 63.56 days (SD = 75.85), with a mean of 80.41 days of abstinence (SD = 74.52) and 3.37 previous treatments (SD = 5.49). Mean age upon crack use initiation was 22.61 years (SD = 8.06), and the most frequent motivation to start using crack was curiosity (78.3%). The mean lifetime duration of crack use was 82.26 months (SD = 74.76), and the physical complications most frequently reported were weight loss (93.5%), followed by sleep problems (87%). In this study, the most prevalent psychiatric diagnoses were major depressive episode (60.87%), followed by post-traumatic stress disorder (52.17%) and generalized anxiety disorder (13.07%).

CONCLUSIONS

Overall, a pattern of high consumption of crack was observed. The results show a high frequency of mood and anxiety disorders, with the highest frequencies found for major depressive episode and post-traumatic stress disorder.

Brain-derived neurotrophic factor in substance use disorders: A systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is associated with several neurodegenerative and psychiatric disorders. It is not clear, however, whether BDNF levels are modified in substance use disorders (SUDs).

METHODS

We conducted a systematic search of electronic databases to identify studies comparing peripheral plasma or serum BDNF levels in adults with SUDs vs. non-user controls. Forty studies were included in the meta-analysis involving a total of 2238 participants with SUDs and 2574 controls.

RESULTS

After trim and fill adjustment, current drug users presented lower serum BDNF levels (SMD = -0.99, 95%CI -1.40 to -0.58, I² = 95.9) than non-user controls. However, this difference disappears during withdrawal. Studies using serum or plasma BDNF samples have shown different results. Subgroup analysis revealed lower levels of serum BDNF in alcohol users (SMD = -0.70, 95%CI -1.15 to -0.25, I² = 89.81) and crack/cocaine users (SMD = -1.78, 95%CI -2.92 to -0.65, I² = 97.59) than controls. Meta-regression analysis revealed that gender, age, and age of first use moderate the effects of drug use in peripheral BDNF levels.

CONCLUSIONS

Peripheral BDNF levels are decreased in the serum, but not the plasma, of active drug users. Altogether, these findings suggest that BDNF levels may be related to acute use and addiction severity and also point to BDNF's potential utility as a biomarker in this population.

Peripheral levels of BDNF and opiate-use disorder: literature review and update

Several neurobiological factors are related to opiate-use disorder (OUD), and among them, neurotrophins have a relevant role. Brain-derived neurotrophic factor (BDNF) is a central neurotrophin involved in many neuronal processes, and it has been related to several psychiatric diseases and addictive disorders. BDNF can be measured in plasma and serum; its levels may reflect BDNF concentrations in the central nervous system (CNS) and, indirectly, CNS processes. Hence, peripheral BDNF could be a biomarker in clinical practice. This manuscript explores the findings about peripheral BDNF and OUD in humans. Opiates induce neurotoxicity in the CNS, which may be correlated with modifications in BDNF expression. Thus, basal levels of peripheral BDNF in OUD patients may be altered, which could be modified with abstinence. Also, opiates may modify epigenetic processes that may be associated with peripheral concentrations of BDNF, and in this line, withdrawal could reflect recovering processes in the CNS. Additionally, treatment modifies the peripheral concentrations of BDNF, but the clinical implications of those changes are yet not elucidated. No specific conclusion can be performed and more investigation in this area is necessary to elucidate the real potential of peripheral BDNF as a biomarker.

Active Brazilian crack cocaine users: nutritional, anthropometric, and drug use profiles

Objective:

To evaluate the nutritional status of crack users and to analyze its correlation with drug use profiles.

Methods:

Cross-sectional study with 108 crack users. Anthropometric data were assessed through body mass index (BMI) and bioimpedance (BIA) measurements. A blood test to analyze hematocrit, hemoglobin, glucose, and lipid profiles was also performed. Crack use was determined through a standardized interview.

Results:

Based on BMI and BIA, most individuals were eutrophic (about 70%). Regarding hematological parameters, we found that hemoglobin and hematocrit levels were below normal for 32.4 and 30.6% of patients, respectively. Considering normal parameters, a large part of the sample (60.2%) had low levels of HDL cholesterol and high levels of triglycerides (38%). There were no significant correlations between drug profile and nutritional variables.

Conclusion:

This is a pioneering study that examines the nutritional status of crack users. Our results showed that most crack users present normal anthropometric findings and the prevalence of underweight is low. However, blood analysis showed changes and a specific type of malnutrition.

Health outcomes associated with crack-cocaine use: Systematic review and meta-analyses

BACKGROUND

Crack-cocaine use is prevalent largely in socio-economically marginalized populations in the Americas. Its use has been associated with diverse health outcomes, yet no recent or systematic reviews of these exist.

METHODS

A systematic review of health outcomes associated with crack-cocaine use was performed, using MEDLINE, Scopus, Web of Science, CINAHL, PsycINFO, and LILACS up to October 2016. Search terms included crack-cocaine and health outcome-related keywords, targeting peer-reviewed studies on quantified health outcomes associated with crack-cocaine use. Random effects meta-analyses produced pooled odds ratios. Levels of evidence for major results were assessed using the GRADE approach. A review protocol was registered with PROSPERO (CRD42016035486).

RESULTS

Of 4700 articles returned, 302 met eligibility criteria, reporting on health outcomes for 14 of 22 ICD-10 chapters. Conclusive evidence and meta-analyses showed positive associations between crack-cocaine use and blood/sexually transmitted diseases (HIV and hepatitis C virus, others); moderate evidence and meta-analyses supported associations with neonatal health, and violence. There were mixed associations for mental and other health outcomes, yet insufficient evidence to perform meta-analyses for many categories (e.g., mortality). Most underlying research was of limited or poor quality, with crack-cocaine commonly assessed as a secondary covariate.

CONCLUSIONS

Crack-cocaine use was associated with a range of health outcomes, although it was unclear if there was direct causal impact, interactions between risk factors, or external drivers of both crack-cocaine use and outcomes. Rigorous epidemiological studies are needed to systematically assess health outcomes of crack-cocaine use and underlying pathways, also to inform evidence-based interventions.

Brain-derived neurotrophic factor levels and depression during methamphetamine withdrawal

BACKGROUND

Depression symptoms is highly comorbid with methamphetamine (METH) dependence. Except for the role in the pathophysiology of depression symptoms, brain-derived neurotrophic factor (BDNF) is also involved in the METH dependence. The present study aims to explore whether BDNF plays a role in the development of depression symptoms during METH withdrawal.

METHODS

We recruited 179 patients with METH dependence who were followed up for two weeks. Ultimately, 131 (73.2%) patients finished the follow-up. Besides, 90 healthy controls were also recruited. Serum BDNF levels were measured by DuoSet ELISA Development System upon admission. The short form (13 items) of the Beck Depression Inventory (BDI) and Amphetamine Withdrawal Questionnaire (AWQ) were used to measure the depression and withdrawal symptoms. Patients with BDI score ≥ 8 were identified to have depression symptoms.

RESULTS

Of the 131 patients, 64 (48.9%) were identified to have depression symptoms at the two-week endpoint. Patients with depression symptoms showed significantly lower BDNF levels than those with no depression symptoms. Serum BDNF levels (≤ 1251.0pg/ml) were independently associated with the development of depression symptoms during METH withdrawal (OR = 3.50, 95% CI, 1.14-10.73, p = 0.028).

LIMITATIONS

BDNF levels were tested in serum but not in brain and the baseline BDI and AWQ scores between the depression and non-depression groups were not matched. Besides, the follow-up time was relatively short.

CONCLUSIONS

Our study demonstrated that patients with serum BDNF levels ≤ 1251.0pg/ml had higher risk of depression symptoms during METH withdrawal.

Differences in biomarkers of crack-cocaine adolescent users before/after abstinence

AIMS

To measure the variation in Brain-Derived Neurotrophic Factor (BDNF), Thiobarbituric Acid Reactive Substances (TBARS) and interleukin (IL) levels in crack-cocaine dependent adolescents after 21days of abstinence, comparing to levels found in a group of healthy controls.

DESIGN

Cross-sectional nested on a short follow-up study.

SETTING

Two inpatient treatment units for adolescents, and a low-income neighborhood.

PARTICIPANTS

90 adolescents, of both genders, with diagnosis of crack cocaine dependence, and 81 healthy adolescents.

MEASUREMENTS

Serum levels of IL-6, IL-10, TBARS and BDNF were assessed on admission and discharge. Drug addiction severity was assessed by the Addiction Severity Index - Teen Version (T-ASI) and Cocaine Craving Questionnaire - Brief version (CCQ-b). Psychiatric comorbidities were assessed by the Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime Version (K-SADS-PL). Generalized Estimating Equations (GEE) were used to estimate the IL-6, IL-10, TBARS and BDNF levels, adjusted for confounders. Hedges' g was used to estimate effect size.

FINDINGS

TBARS (p=0.005, d=0.04), IL-6 (p=0.027, d=0.40) and IL-10 (p=0.025, d=0.41) were elevated and BDNF (p<0.001, d=0.62) was reduced (p<0.001), in patients, in comparison to controls, at admission time. Variation in those levels between admission and discharge were not significant.

CONCLUSIONS

Crack-cocaine use seems to be associated with inflammatory and oxidative imbalances in adolescents.

Effects of crack cocaine addiction and stress-related genes on peripheral BDNF levels

This study examined the effects of glucocorticoid receptor (NR3C1), corticotropin-releasing hormone receptor 1 (CRHR1), and brain-derived neurotrophic factor (BDNF) genes on susceptibility to crack cocaine addiction and BDNF levels. Crack addicted patients who sought treatment (n = 280) and non-addicted individuals (n = 241) were assessed. Three SNPs in NR3C1 (rs6198, rs41423247, and rs10052957), three in CRHR1 (rs12944712, rs110402, and rs878886), and one in BDNF (rs6265) were genotyped. No significant effect was seen in the case-control analyses. Crack cocaine addicted patients showed significantly lower serum BDNF levels. Significant effects were observed for NR3C1 rs41423247 and rs10052957. These effects were restricted to non-addicted individuals and they were supported by significant gene-by-disease status interactions. For CRHR1, all SNPs were associated with BDNF levels. Although there were significant effects only in the analysis restricted to non-addicted individuals, the lack of significant results in the gene-by-disease status interaction analyses suggest a general effect on BDNF levels. The haplotype analyses presented the same effect seen in the single marker analyses. This study suggests that SNPs in the NR3C1 and CRHR1 genes may influence BDNF levels, but this effect is blunted in the context of crack cocaine addiction. Therefore, our data may be interpreted in light of several studies showing pronounced effects of crack cocaine on BDNF levels. Since peripheral BDNF is a biomarker for several psychiatric phenotypes, our results may be useful in interpreting previous associations between stress-related SNPs, drug addiction, and depression.

Prefrontal cortical BDNF: A regulatory key in cocaine- and food-reinforced behaviors

Brain-derived neurotrophic factor (BDNF) affects synaptic plasticity and neural structure and plays key roles in learning and memory processes. Recent evidence also points to important, yet complex, roles for BDNF in rodent models of cocaine abuse and addiction. Here we examine the role of prefrontal cortical (PFC) BDNF in reward-related decision making and behavioral sensitivity to, and responding for, cocaine. We focus on BDNF within the medial and orbital PFC, its regulation by cocaine during early postnatal development and in adulthood, and how BDNF in turn influences responding for drug reinforcement, including in reinstatement models. When relevant, we draw comparisons and contrasts with experiments using natural (food) reinforcers. We also summarize findings supporting, or refuting, the possibility that BDNF in the medial and orbital PFC regulate the development and maintenance of stimulus-response habits. Further investigation could assist in the development of novel treatment approaches for cocaine use disorders.

Cocaine-induced Psychosis and Brain-derived Neurothrophic Factor in Patients with Cocaine Dependence: Report of Two Cases

Brain-derived neurotrophic factor (BDNF) is linked to numerous brain functions. In addition, BDNF alterations contribute to neurological, mental, and addictive disorders. Cocaine dependence has received much attention recently due to its prevalence and psychological effects. Symptoms of psychosis are one of the most serious adverse events precipitated by cocaine use. It is particularly important to identify patients at risk of developing cocaine-induced psychosis (CIP). We described two cases of patients with cocaine dependence who presented with CIP and had changes in their BDNF levels during the psychotic episode. BDNF levels were initially low in both patients, and then decreased by more than 50% in association with CIP. The relationship between BDNF and psychosis is described in the literature. These cases revealed that BDNF levels decreased during a CIP episode and, thus, it is necessary to investigate BDNF and its relationship with CIP further.

Genotoxicity and mutagenicity induced by acute crack cocaine exposure in mice

CONTEXT

Crack cocaine is an illicit drug derived from cocaine, in which use and abuse have increased around the world, especially in developing countries.

OBJECTIVES

The aim of this study was to evaluate genomic damage in multiple organs of mice following acute exposure to crack cocaine. For this purpose, single cell gel (comet) assay in peripheral blood, liver, kidney, and brain cells was performed and micronucleus test for bone narrow and liver cells was also made in this setting.

MATERIAL AND METHODS

A total of 20 C57BL/10 male mice were distributed into four groups, as follows: 0, 4.5, 9, and 18 mg/kg b.w. of crack cocaine dissolved to 1% dimethyl sulfoxide by intraperitoneal (i.p.) route. All animals were sacrificed 24 h after i.p. injection.

RESULTS

The results showed that crack cocaine induced DNA damage in peripheral blood, and brain cells for higher doses used as depicted by single cell gel (comet) assay data. Analysis of kidney cells showed no genetic damage for all groups tested. The number of micronucleated cells did not increase after crack cocaine exposure in bone narrow or liver cells.

CONCLUSION

In summary, crack cocaine is a genotoxic agent in peripheral blood, liver, and brain cells but not mutagenic in multiple organs of mice.

Brain-derived neurotrophic factor is a novel target gene of the has-miR-183/96/182 cluster in retinal pigment epithelial cells following visible light exposure

Light-induced retinal injury is clinically and experimentally well-documented. It may be categorized into three types: Photothermal, photomechanical and photochemical injuries. To date, the variation in the hsa-miR-183/96/182 cluster and its potential target genes in human primary retinal pigment epithelial (RPE) cells, following visible light exposure, has not been reported. In the present study, RPE cells were exposed to 4 h of constant visible light. The expression of the hsa-miR-183/96/182 cluster was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and its potential target genes were investigated. Additionally, hsa-miR-183, hsa-miR-96, hsa-miR-182 and has-miR-183/96/182 mimics were designed and synthesized in vitro, and transfected into the RPE cells. Subsequently, the expression of brain-derived neurotrophic factor (BDNF) mRNA and protein was measured, using RT-qPCR and western blotting, respectively. The regulation of miRNAs to the BDNF gene were then validated using a dual luciferase reporter gene assay system. The expression of hsa-miR-183, hsa-miR-96 and hsa-miR-182 significantly increased in RPE cells following 4 h of visible light exposure, compared with RPE cells that had been exposed to dark conditions (P<0.01). Following RPE cell transfection with mimics, BDNF mRNA and protein expression in the RPE cells was significantly downregulated compared with control RPE cells (P<0.05, P<0.01, respectively). Similarly, the ratio of Renilla luciferase/firefly luciferase significantly decreased in the RPE cells of the mimic + wild type (WT) group compared with cells of the psiCHECK(TM)-2 (a vector lacking the sequence of the BDNF gene), wild type and mimic + mutation groups (P<0.05, P<0.01). The present study suggests that BDNF is a target gene of the has-miR-183-96-182 cluster in RPE cells. The present study suggests an underlying protective mechanism against retinal light injury and may provide a novel target for the prevention and treatment of light-induced retinal injury.

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.

Changes in brain-derived neurotrophic factor (BDNF) during abstinence could be associated with relapse in cocaine-dependent patients

Brain-derived neurotrophic factor (BDNF) is involved in cocaine craving in humans and drug seeking in rodents. Based on this, the aim of this study was to explore the possible role of serum BDNF in cocaine relapse in abstinent addicts. Forty cocaine dependent subjects (DSM-IV criteria) were included in an inpatient 2 weeks abstinence program. Organic and psychiatric co-morbidities were excluded. Two serum samples were collected for each subject at baseline and at after 14 abstinence days. After discharge, all cocaine addicts underwent a 22 weeks follow-up, after which they were classified into early relapsers (ER) (resumed during the first 14 days after discharge,) or late relapsers (LR) (resumed beyond 14 days after discharge). The only clinical differences between groups were the number of consumption days during the last month before detoxification. Serum BDNF levels increased significantly across the 12 days of abstinence in the LR group (p=0.02), whereas in the ER group BDNF remained unchanged. In the ER group, the change of serum BDNF during abstinence negatively correlated with the improvement in depressive symptoms (p=0.02). These results suggest that BDNF has a role in relapse to cocaine consumption in abstinent addicts, although the underlying neurobiological mechanisms remain to be clarified.

Brain-Derived Neurotrophic Factor and Delayed Verbal Recall in Crack/Cocaine Dependents

BACKGROUND/AIMS

Considering the role of brain-derived neurotrophic factor (BDNF) in memory processes and its peripheral response during the detoxification of cocaine, the aim of this study was to investigate whether plasma BDNF levels could be related to memory performance in women with crack/cocaine dependence.

METHODS

Twenty-five abstinent female crack/cocaine users (CCD) and 25 unmedicated healthy women (HW), carefully matched for age and years of formal education, were assessed regarding memory performance. Logical Memory was used to assess the immediate verbal recall (IVR), delayed verbal recall (DVR) and memory retention. Plasma BDNF levels were measured by Elisa immunoassay. Beck Depression Inventory was used to assess the severity of depressive symptoms, and the Cocaine Selective Severity Assessment the severity of cocaine abstinence symptoms.

RESULTS

The CCD group had lower DVR scores and higher plasma BDNF levels when compared to HW group. In addition, a linear regression model showed that BDNF levels predicted DVR scores within CCD group independently of depressive symptoms (R = 0.51; R(2) = 0.26; t(22) = 4.025, p = 0.03).

CONCLUSION

Despite higher plasma BDNF levels, crack users exhibited memory impairments when compared to healthy women. Specifically, peripheral BDNF levels predicted better cognitive performance only within individuals who already had cognitive impairment.

Multiple faces of BDNF in cocaine addiction

Brain-derived neurotrophic factor (BDNF) has been found to play roles in many types of plasticity including drug addiction. Here, we focus on rodent studies over the past two decades that have demonstrated diverse roles of BDNF in models of cocaine addiction. First, we will provide an overview of studies showing that cocaine exposure alters (and generally increases) BDNF levels in reward-related regions including the ventral tegmental area, nucleus accumbens, prefrontal cortex, and amygdala. Then we will review evidence that BDNF contributes to behavioral changes in animal models of cocaine addiction, focusing on conditioned place preference, behavioral sensitization, maintenance and reinstatement of self-administration, and incubation of cocaine craving. Last, we will review the role of BDNF in synaptic plasticity, particularly as it relates to plasticity of AMPA receptor transmission after cocaine exposure. We conclude that BDNF regulates cocaine-induced behaviors in a highly complex manner that varies depending on the brain region (and even among different cell types within the same brain region), the nature of cocaine exposure, and the "addiction phase" examined (e.g., acquisition vs maintenance; early vs late withdrawal). These complexities make BDNF a daunting therapeutic target for treating cocaine addiction. However, recent clinical evidence suggests that the serum BDNF level may serve as a biomarker in cocaine addicts to predict future relapse, providing an alternative direction for exploring BDNF's potential relevance to treating cocaine addiction.

Oxidative stress and BDNF as possible markers for the severity of crack cocaine use in early withdrawal

RATIONALE

An important goal of addiction research is to discover neurobiological markers that could predict the severity of addiction and help to determine appropriate treatment. Brain-derived neurotrophic factor (BDNF) and thiobarbituric acid reactive substances (TBARS) are being related to cerebral plasticity and impairment caused by substance abuse.

OBJECTIVES

This study aims to evaluate alteration of TBARS and BDNF levels among crack cocaine users during early drug withdrawal and its relationship to severity of drug use.

METHODS

Forty-nine adults crack cocaine users were recruited at a public psychiatric hospital with a specialized addiction treatment unit. Blood sample was collected at intake and discharge for the analysis of TBARS and BDNF measures. Information about drug use was assessed by the Addiction Severity Index 6th Version (ASI-6). Detailed information about crack cocaine use was obtained through the "Profile of the crack cocaine user." Severity of crack use was estimated using information from age of first crack use, years of crack use, and crack rocks used in the previous 30 days.

RESULTS

There is a positive correlation between TBARS levels and severity of crack cocaine use (R = 0.304, p = 0.04) and a negative correlation between BDNF and severity of crack cocaine use (R = -0.359, p = 0.01) at discharge. Also, we found an inverse correlation between TBARS and BDNF levels (R = -0.294, p = 0.004) at discharge.

CONCLUSIONS

Our findings suggest that BDNF and TBARS could be possible markers for the severity of drug use. Further studies may show how those markers could be related to staging, prognosis, and treatment in crack cocaine dependence.