Oxytocin Receptor Exon III Methylation in the Umbilical Cord Blood of Newborns With Prenatal Exposure to Crack Cocaine

BACKGROUND

Prenatal cocaine exposure (PCE) is associated with behavioral, cognitive, and social consequences in children that might persist into later development. However, there are still few data concerning epigenetic mechanisms associated with the effects of gestational cocaine exposure, particularly in human newborns.

AIMS

We investigated the effects of PCE on DNA methylation patterns of the Oxytocin Receptor (OXTR) gene in the umbilical cord blood (UCB). The relationship between UCB DNA methylation levels and the severity of the mother's cocaine use during pregnancy was also evaluated.

METHODS

In this cross-sectional study, 28 UCB samples of newborns with a history of crack cocaine exposure in utero and 30 UCB samples of non-exposed newborns (NEC) were compared for DNA methylation levels at two genomic loci located in exon III of the OXTR gene (OXTR1 and OXTR2) through pyrosequencing. Maternal psychopathology was investigated using the Mini International Neuropsychiatric Interview, and substance use characteristics and addiction severity were assessed using the Smoking and Substance Involvement Screening Test (ASSIST).

RESULTS

No differences between newborns with a history of PCE and NEC were observed in OXTR1 or OXTR2 DNA methylation levels. However, regression analyses showed that maternal addiction severity for crack cocaine use predicted OXTR1 DNA methylation in newborns.

CONCLUSION

These data suggest that OXTR methylation levels in the UCB of children are affected by the severity of maternal crack cocaine usage. Larger studies are likely to detect specific changes in DNA methylation relevant to the consequences of PCE.

Association between the Intron 8 VNTR Polymorphism of the DAT1 Gene and Crack Cocaine Addiction

BACKGROUND

This study aims to compare allele and genotype frequencies of a 30-bp variable number of tandem repeats (VNTR) polymorphism of the DAT1 gene, located at intron 8, between adult crack cocaine users and nonaddicted individuals. Due to its involvement in drug addiction, this gene is a good candidate for molecular studies.

METHODS

A cross-sectional sample of 239 current adult crack abusers or dependents from in- and outpatient clinics and 211 control individuals was collected in Brazil. They were evaluated using ASRS, ASI-6, WAIS-III, and MINI assessments. DNA samples extracted from whole blood were genotyped for the intron 8 VNTR in DAT1.

RESULTS

Logistic regression analysis was performed and controlled for gender, age, ethnicity, educational level, and comorbidities of clinical interest (generalized anxiety disorder, suicide risk, major depressive episode, and attention deficit/hyperactivity disorder). This analysis showed that the 6R6R genotype was associated with crack cocaine addiction (OR = 1.844; CI = 1.101-3.089; p = 0.020).

CONCLUSIONS

Our results are consistent with the role of DAT1 in the neurobiology of drug addiction. Nevertheless, the study of other genes, environmental factors, and their interactions is also important to gain a broader understanding of this condition.

TBARS and BDNF levels in newborns exposed to crack/cocaine during pregnancy: a comparative study

Objectives:

To compare levels of a marker of lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and brain-derived neurotrophic factor (BDNF) in umbilical cord blood (UCB) between newborns exposed to crack/cocaine in utero (exposed newborns [EN], n=57) and non-exposed newborns (NEN, n=99), as well as in maternal peripheral blood at delivery.

Methods:

This was a cross-sectional study. Potential confounders, including perinatal parameters, psychopathology, and use of other substances, were assessed.

Results:

After adjusting for potential confounders, adjusted mean BDNF was significantly higher in EN (3.86 ng/mL, 95% confidence interval [95%CI] 2.29-5.43) than in NEN (0.85 ng/mL, 95%CI 0.47-1.23; p < 0.001; Cohen effect size: 1.12), and significantly lower in crack/cocaine mothers than in control mothers (4.03 ng/mL, 95%CI 2.87-5.18 vs. 6.67 ng/mL, 95%CI 5.60-7.74; p = 0.006). The adjusted mean TBARS level was significantly lower in EN (63.97 µM MDA, 95%CI 39.43-88.50) than NEN (177.04 µM MDA, 95%CI 140.93-213.14; p < 0.001; effect size = 0.84), with no difference between mother groups (p = 0.86).

Conclusions:

The changes in TBARS levels observed in EN suggest that fetuses exposed to cocaine mobilize endogenous antioxidant routes since very early stages of development. The increase in BDNF levels in EN might indicate changes in fetal development, whereas the changes in BDNF levels in mothers provide evidence of the complex metabolic processes involved in drug use during pregnancy.

IL-6 and IL-10 levels in the umbilical cord blood of newborns with a history of crack/cocaine exposure in utero: a comparative study

INTRODUCTION

Prenatal cocaine exposure (PCE) is associated with neurobehavioral problems during childhood and adolescence. Early activation of the inflammatory response may contribute to such changes. Our aim was to compare inflammatory markers (IL-6 and IL-10) both in umbilical cord blood and in maternal peripheral blood at delivery between newborns with history of crack/cocaine exposure in utero and non-exposed newborns.

METHODS

In this cross-sectional study, 57 newborns with a history of crack/cocaine exposure in utero (EN) and 99 non-exposed newborns (NEN) were compared for IL-6 and IL-10 levels. Sociodemographic and perinatal data, maternal psychopathology, consumption of nicotine and other substances were systematically collected in cases and controls.

RESULTS

After adjusting for potential confounders, mean IL-6 was significantly higher in EN than in NEN (10,208.54, 95% confidence interval [95%CI] 1,328.54-19,088.55 vs. 2,323.03, 95%CI 1,484.64-3,161.21; p = 0.007; generalized linear model [GLM]). Mean IL-10 was also significantly higher in EN than in NEN (432.22, 95%CI 51.44-812.88 vs. 75.52, 95%CI 5.64-145.39, p = 0.014; GLM). Adjusted postpartum measures of IL-6 were significantly higher in mothers with a history of crack/cocaine use (25,160.05, 95%CI 10,958.15-39,361.99 vs. 8,902.14, 95%CI 5,774.97-12,029.32; p = 0.007; GLM), with no significant differences for IL-10. There was no correlation between maternal and neonatal cytokine levels (Spearman test, p ≥ 0.28 for all measures).

CONCLUSIONS

IL-6 and IL-10 might be early biomarkers of PCE in newborns. These findings could help to elucidate neurobiological pathways underlying neurodevelopmental changes and broaden the range of possibilities for early intervention.

Crack Cocaine Use in Adolescents: Clinical Characteristics and Predictors of Early Initiation

OBJECTIVE

To describe the clinical characteristics of adolescents with crack cocaine dependence and possible predictors of transition from drug experimentation to crack cocaine dependence.

METHODS

This cross-sectional study enrolled a consecutive sample of 90 adolescents admitted to a psychiatric inpatient unit in the city of Porto Alegre in southern Brazil for crack cocaine detoxification between May 2011 and November 2012. Comorbid psychological conditions were assessed using the Kiddie-SADS-Present and Lifetime Version, and severity of drug use was assessed using the Teen Addiction Severity Index (T-ASI). Comorbidities were compared with those in a community sample of non-drug using controls (n = 81).

RESULTS

Patients' mean age was 15.6 years (85.6% boys, 14.4% girls). Seventy-nine (93.2%) met criteria for cocaine dependence (DSM-IV-TR), while 78 (91.8%) had symptoms consistent with cocaine abuse. All patients had experimented with at least 1 other addictive substance before crack cocaine: 61.4%, tobacco (mean age at first use = 11.61 years); 44.3%, alcohol (age at first use = 12.43 years); and 54.5%, cannabis (age at first use = 12.15 years). Patients had used crack cocaine 23.2 days in the last month, and the mean age at first use of crack cocaine was 13.38 years. The most common psychiatric comorbidity was conduct disorder (81.8%), followed by oppositional defiant disorder (52.3%) and attention-deficit/hyperactivity disorder (44.3%), all of which were more prevalent in the patient population than in controls (P < .001). The T-ASI questionnaire showed severe consequences of drug use in most areas of life assessed. The mean time between onset of drug experimentation and crack cocaine dependence was 2.53 (SD = 1.96) years. When Cox regression models were applied, we found that predictors of earlier progression to using crack cocaine were age at first use of any drug (hazard ratio [HR] = 0.79 [95% CI, 0.71-0.88]; P < .001) and age at admission (HR = 0.7 [95% CI, 0.57-0.87]; P = .001).

CONCLUSIONS

Patients were found to have a multitude of comorbid conditions, which supports the idea of treatment by a multidisciplinary health care team. For each year of delay in the age at first drug use, the chance of crack cocaine initiation is reduced by 18%. Prevention programs aimed at delaying experimentation with addictive substances, especially "gateway" drugs, could delay the progression to crack cocaine dependence.

Crack cocaine users show differences in genotype frequencies of the 3' UTR variable number of tandem repeats of the dopamine transporter gene (DAT1/SLC6A3)

BACKGROUND

Due to the mechanism of action of the dopamine transporter (DAT) in drug addiction, the DAT1 gene is a potential candidate for molecular studies. This paper aims to compare the prevalence of allele and genotype frequencies created by the 3' UTR variable number of tandem repeats (VNTR) of this gene between crack cocaine users and controls.

METHODS

A cross-sectional sample of 237 current adult crack cocaine abusers or dependents (DSM-IV TR criteria) from in- and outpatient clinics in southern Brazil and 205 community controls were compared. The subjects were evaluated using the Adult ADHD Self-Report Scale, the Mini-International Neuropsychiatric Interview - short version, and the Wechsler Intelligence Scale. DNA samples were genotyped for the DAT1 3' VNTR.

RESULTS

Logistic regression analysis was performed to compare the frequency of the 10.10 genotype (the putative risk genotype) to those of other genotypes. A significant difference (p = 0.04, OR = 1.758, CI = 1.026-3.012) indicating an increased frequency of the 10.10 genotype in the cases (59.9%) compared to the controls (49.3%) was verified using clinical and demographic covariates.

CONCLUSIONS

This is one of the first genetic association studies on crack cocaine users in the literature. The results suggest an influence of the DAT1 gene, namely the 3' VNTR 10.10 genotype. However, more analyses will confirm and clarify its contribution as a possible risk factor for crack cocaine dependence.

Is ADHD a risk factor independent of conduct disorder for illicit substance use? A meta-analysis and metaregression investigation

OBJECTIVE

To investigate meta-analytically if the association between ADHD and illicit substance use (ISU) is maintained when controlling for conduct disorder/oppositional-defiant disorder (CD/ODD).

METHOD

A systematic literature review was conducted through Medline from 1980 to 2008. Data extracted and selections made by one author were reviewed by another.

RESULTS

Fifteen articles presented odds ratios (ORs) for the development of ISU in individuals with ADHD controlling for CD/ODD. In total, the study covered results for more than 1,000 individuals. The combined OR for studies that included in their analysis exclusively ISU was 1.35 (0.90-2.03), p = .15, heterogeneity = 55%. Lack of control for socioeconomic status was related with a weaker association between ADHD and ISU.

CONCLUSION

The existing data do not indicate that ADHD increases the risk of ISU beyond the effects of CD/ODD. However, the combination of all existing data is limited in power to detect a small increase in chance.

Is attention-deficit/hyperactivity disorder associated with illicit substance use disorders in male adolescents? A community-based case-control study

AIMS

This study aims at evaluating the association between attention-deficit/hyperactivity disorder (ADHD) and illicit substance use disorders (SUD) (marijuana, cocaine and inhalants), controlling for the association with conduct disorder (CD), in a community-based sample of adolescents.

DESIGN

Case-control, community-based study.

SETTING

A delimited geographical area in the South of Brazil, served by four public health clinics.

PARTICIPANTS

A total of 968 male adolescents (15-20 years of age) were screened for SUD in their households. Of the subjects who were screened positive, we selected 61 cases with illicit SUD. For each case we selected, from the group which was screened negative, three controls without illicit or alcohol SUD, matched by age and proximity with the case's household.

MEASUREMENTS

The screening instrument was the Alcohol Smoking and Substance Screening Test (ASSIST). SUD diagnoses were assessed by the drug section of the Mini International Neuropsychiatry Interview (MINI). Other psychiatric diagnoses were based on semistructured (Schedule for Affective Disorders and Schizophrenia for School-Age Children-epidemiological version; MINI) and clinical interviews.

FINDINGS

Adolescents with ADHD presented a significantly higher odds ratio (OR) for illicit SUD than youths without ADHD, even after adjusting for potential confounders (CD, ethnicity, religion and estimated IQ) (OR = 9.12; 95% CI = 2.84-29.31, P < 0.01).

CONCLUSIONS

Our results suggest an association between ADHD and illicit SUD in Brazilian adolescents that is not mediated by CD. These findings are potentially important from a prevention perspective because treatments are available for ADHD.

Co-ocorrência entre transtorno de déficit de atenção/hiperatividade e uso de substâncias psicoativas

Existe forte associação entre o transtorno de déficit de atenção/hiperatividade (TDAH) e o transtorno por uso de substâncias psicoativas (TUSP) em estudos clínicos e comunitários. Estimam-se que aproximadamente 30% dos sujeitos com TUSP apresentem comorbidade com o TDAH, taxa significativamente maior do que a vista na população geral. Vários estudos vêm analisando o possível efeito do TDAH no risco de desenvolvimento de TUSP. O presente artigo revisa a literatura disponível às seguintes questões: a) natureza da associação entre o TDAH e o TUSP; b) efeitos do TDAH no TUSP; c) tratamento do TDAH na concomitância do diagnóstico de TUSP. Por fim, é oferecida uma integração das diferentes informações, sob um enfoque predominantemente clínico.

The acute effect of methylphenidate in Brazilian male children and adolescents with ADHD: a randomized clinical trial

OBJECTIVE

To evaluate the acute efficacy of methylphenidate (MPH) in Brazilian male children and adolescents with ADHD.

METHOD

In a 4-day, double-blind, placebo-controlled, randomized, fix dose escalating, parallel-group trial, 36 ADHD children and adolescents were allocated to two groups: MPH (n = 19) and placebo (n = 17). Participants were evaluated pre- and posttreatment using the 10-item Conners Abbreviated Rating Scale (ABRS), the Children's Global Assessment Scale (CGAS), and a simplified version of the Continuous Performance Test (CPT).

RESULTS

The MPH group had a significantly greater decrease in ABRS scores and a significantly higher increase in CGAS scores than the placebo group (p < 0.01). The MPH group showed also a significantly higher proportion of patients with a robust improvement (decrement of at least 50% in the ABRS score after the intervention) than the placebo group (p < 0.01). The MPH effect size for the ABRS was 1.05 (95% CI = 0.73-1.37).

CONCLUSION

Our results extend the efficacy of MPH on the ADHD core symptoms extensively demonstrated in clinical trials with samples from some developed countries to a sample from a developing country where a diverse culture may modulate the clinical presentation of the disorder.

The acute effect of methylphenidate on cerebral blood flow in boys with attention-deficit/hyperactivity disorder

Methylphenidate (MPH) is the most commonly prescribed treatment for attention-deficit/hyperactivity disorder (ADHD). The therapeutic mechanisms of MPH are not, however, fully understood. We studied the effects of MPH on brain activity in male children and adolescents with ADHD, using the blood flow radiotracer technetium-99m ethyl cysteinate dimer ((99m)Tc-ECD) and single-photon emission tomography (SPET). The study was randomized, double blind, and placebo controlled (MPH group, n=19; placebo group, n=17), Radiotracer was administered during the performance of the Continuous Performance Test and before and after 4 days of MPH treatment. Statistical parametric mapping (SPM99) analysis showed a significant reduction in regional cerebral blood flow in the left parietal region in the MPH group compared with the placebo group (P<0.05, corrected for multiple comparisons). Our findings suggest that the posterior attentional system, which includes the parietal cortex, may have a role in the mediation of the therapeutic effects of MPH in ADHD.

[Limitations and alternatives to the implementation of a program for drug users at risk of HIV infection using the Social Network Approach]

The authors describe the development of a preventive program focused on intravenous drug users at risk of HIV infection, using the Social Network Approach as the intervention model. The authors describe the project's steps in a large university hospital in southern Brazil, emphasizing the unique methods and techniques developed by the treatment staff. Problems encountered during the project development are discussed, aimed at identifying the reasons why the program only achieved partial success. The authors identify critical issues, such as the use of a new technique not previously tried in Brazil, difficulties in maintaining IV drug users in treatment, lack of infrastructure for walk-in treatment, and the challenge of motivating staff and patients to continue treatment. The authors conclude by listing suggestions aimed at facilitating the development of new projects based on the same conceptual model.