Regional brain morphometry and impulsivity in adolescents following prenatal exposure to cocaine and tobacco.

IMPORTANCE: Animal studies have suggested that prenatal cocaine exposure (PCE) deleteriously influences the developing nervous system, in part attributable to its site of action in blocking the function of monoamine reuptake transporters, increasing synaptic levels of serotonin and dopamine. OBJECTIVE: To examine the brain morphologic features and associated impulsive behaviors in adolescents following prenatal exposure to cocaine and/or tobacco. DESIGN: Magnetic resonance imaging data and behavioral measures were collected from adolescents followed up longitudinally in the Maternal Lifestyle Study. SETTING: A hospital-based research center. PARTICIPANTS: A total of 40 adolescent participants aged 13 to 15 years were recruited, 20 without PCE and 20 with PCE; a subset of each group additionally had tobacco exposure. Participants were selected and matched based on head circumference at birth, gestational age, maternal alcohol use, age, sex, race/ethnicity, IQ, family poverty, and socioeconomic status. MAIN OUTCOME MEASURES: Subcortical volumetric measures of the thalamus, caudate, putamen, pallidum, hippocampus, amygdala, and nucleus accumbens; cortical thickness measures of the dorsolateral prefrontal cortex and ventral medial prefrontal cortex; and impulsivity assessed by Conners' Continuous Performance Test and the Sensation Seeking Scale for Children. RESULTS: After controlling for covariates, cortical thickness of the right dorsolateral prefrontal cortex was significantly thinner in adolescents following PCE (P = .03), whereas the pallidum volume was smaller in adolescents following prenatal tobacco exposure (P = .03). Impulsivity was correlated with thalamic volume following either PCE (P = .05) or prenatal tobacco exposure (P = .04). CONCLUSIONS AND RELEVANCE: Prenatal cocaine or tobacco exposure can differentially affect structural brain maturation during adolescence and underlie enhanced susceptibility to impulsivity. Additional studies with larger sample sizes are warranted.

Subcortical and cortical structural central nervous system changes and attention processing deficits in preschool-aged children with prenatal methamphetamine and tobacco exposure.

OBJECTIVE: To examine the independent contributions of prenatal methamphetamine exposure (PME) and prenatal tobacco exposure (PTE) on brain morphology among a sample of nonalcohol-exposed 3- to 5-year-old children followed prospectively since birth. STUDY DESIGN: The sample included 20 children with PME (19 with PTE) and 15 comparison children (7 with PTE), matched on race, birth weight, maternal education and type of insurance. Subcortical and cortical volumes and cortical thickness measures were derived through an automated segmentation procedure from T1-weighted structural magnetic resonance images obtained on unsedated children. Attention was assessed using the computerized Conners' Kiddie Continuous Performance Test Version 5 (K-CPT™ V.5). PME effects on subcortical and cortical brain volumes and cortical thickness were tested by general linear model with type III sum of squares, adjusting for PTE, prenatal marijuana exposure, age at time of scan, gender, handedness, pulse sequence and total intracranial volume (for volumetric outcomes). A similar analysis was done for PTE effects on subcortical and cortical brain volumes and thickness, adjusting for PME and the above covariates. RESULTS: Children with PME had significantly reduced caudate nucleus volumes and cortical thickness increases in perisylvian and orbital-frontal cortices. In contrast, children with PTE showed cortical thinning in perisylvian and lateral occipital cortices and volumetric increases in frontal regions and decreases in anterior cingulate. PME was positively related and caudate volume was inversely related to K-CPT reaction time by inter-stimulus interval, a measure of the ability to adjust to changing task demands, suggesting that children with PME may have subtle attentional deficits mediated by caudate volume reductions. CONCLUSIONS: Our results suggest that PME and PTE may have distinct differential cortical effects on the developing central nervous system. Additionally, PME may be associated with subtle deficits in attention mediated by caudate volume reductions.

Neuroimaging of children following prenatal drug exposure.

Recent advances in MR-based brain imaging methods have provided unprecedented capabilities to visualize the brain. Application of these methods has allowed identification of brain structures and patterns of functional activation altered in offspring of mothers who used licit (e.g., alcohol and tobacco) and illicit (e.g., cocaine, methamphetamine, and marijuana) drugs during pregnancy. Here we review that literature, which though somewhat limited by the complexities of separating the specific effects of each drug from other confounding variables, points to sets of interconnected brain structures as being altered following prenatal exposure to drugs of abuse. In particular, dopamine-rich cortical (e.g., frontal cortex) and subcortical (e.g., basal ganglia) fetal brain structures show evidence of vulnerability to intrauterine drug exposure suggesting that during brain development drugs of abuse share a specific profile of developmental neurotoxicity. Such brain malformations may shed light on mechanisms underlying prenatal drug-induced brain injury, may serve as bio-markers of significant intrauterine drug exposure, and may additionally be predictors of subsequent neuro-developmental compromise. Wider clinical use of these research-based non-invasive methods will allow for improved diagnosis and allocation of therapeutic resources for affected infants, children, and young adults.

Treatment of late infantile neuronal ceroid lipofuscinosis by CNS administration of a serotype 2 adeno-associated virus expressing CLN2 cDNA.

Late infantile neuronal ceroid lipofuscinosis (LINCL) is an autosomal recessive, neurodegenerative lysosomal storage disease affecting the CNS and is fatal by age 8 to 12 years. A total average dose of 2.5 10(12) particle units of an adeno-associated virus (AAV) serotype 2 vector expressing the human CLN2 cDNA (AAV2 CU h-CLN2) was administered to 12 locations in the CNS of 10 children with LINCL. In addition to safety parameters, a neurological rating scale (primary variable) and three quantitative magnetic resonance imaging (MRI) parameters (secondary variables) were used to compare the rate of neurological decline for 18 months in treated subjects compared with untreated subjects. Although there were no unexpected serious adverse events that were unequivocally attributable to the AAV2 CU hCLN2 vector, there were serious adverse effects, the etiology of which could not be determined under the conditions of the experiment. One subject died 49 days postsurgery after developing status epilepticus on day 14, but with no evidence of CNS inflammation. Four of the 10 subjects developed a mild, mostly transient, humoral response to the vector. Compared with control subjects, the measured rates of decline of all MRI parameters were slower, albeit the numbers were too small for statistical significance. Importantly, assessment of the neurologic rating scale, which was the primary outcome variable, demonstrated a significantly reduced rate of decline compared with control subjects. Although the trial is not matched, randomized, or blinded and lacked a contemporaneous placebo/sham control group, assessment of the primary outcome variable suggests a slowing of progression of LINCL in the treated children. On this basis, we propose that additional studies to assess the safety and efficacy of AAV-mediated gene therapy for LINCL are warranted.