The PedBE clock accurately estimates DNA methylation age in pediatric buccal cells.

The development of biological markers of aging has primarily focused on adult samples. Epigenetic clocks are a promising tool for measuring biological age that show impressive accuracy across most tissues and age ranges. In adults, deviations from the DNA methylation (DNAm) age prediction are correlated with several age-related phenotypes, such as mortality and frailty. In children, however, fewer such associations have been made, possibly because DNAm changes are more dynamic in pediatric populations as compared to adults. To address this gap, we aimed to develop a highly accurate, noninvasive, biological measure of age specific to pediatric samples using buccal epithelial cell DNAm. We gathered 1,721 genome-wide DNAm profiles from 11 different cohorts of typically developing individuals aged 0 to 20 y old. Elastic net penalized regression was used to select 94 CpG sites from a training dataset (n = 1,032), with performance assessed in a separate test dataset (n = 689). DNAm at these 94 CpG sites was highly predictive of age in the test cohort (median absolute error = 0.35 y). The Pediatric-Buccal-Epigenetic (PedBE) clock was characterized in additional cohorts, showcasing the accuracy in longitudinal data, the performance in nonbuccal tissues and adult age ranges, and the association with obstetric outcomes. The PedBE tool for measuring biological age in children might help in understanding the environmental and contextual factors that shape the DNA methylome during child development, and how it, in turn, might relate to child health and disease.

Rumination and Moderators of Multifinality: Predicting Internalizing Symptoms and Alcohol Use During Adolescence.

Rumination, a perseverative cognitive process that involves repetitively and passively focusing on negative emotions, is a transdiagnostic risk factor for the development of psychopathology. Although rumination has been linked to various forms of psychopathology including depression, anxiety, and alcohol misuse, little is known about the conditions that lead to multifinality. Here, we test putative moderators (Nolen-Hoeksema & Watkins, 2011) of the association between rumination and subsequent internalizing symptoms and frequency of alcohol use during adolescence. Participants included 388 youth (52% girls; 90% Caucasian) in a longitudinal birth cohort study who completed questionnaires in Grades 9 and 11. Brooding, a maladaptive form of rumination measured in Grade 9, was associated with greater internalizing symptoms in Grade 11 and greater perceived peer rejection in Grade 9 amplified this association. Brooding was also associated with greater frequency of alcohol use among adolescents who reported having more friends who use alcohol. Gender differences were also examined. Findings provide support for some of the predictions regarding moderators of multifinality made by Nolen-Hoeksema and Watkins. Implications of understanding divergent trajectories in the prevention of psychopathology are discussed.

Drug Misuse in Adolescents Presenting to the Emergency Department.

OBJECTIVES: Drug misuse is a disturbing, common practice among youth. One in 4 American adolescents reports consuming prescription medications without a clinical indication. We sought to explore current trends of drug misuse in adolescents. METHODS: Using the 37 participating sites of the ToxIC (Toxicology Investigators Consortium) Case Registry, a cross-country surveillance tool, we conducted an observational cohort study of all adolescents (aged 13-18 years) who presented to emergency departments with drug misuse and required a bedside medical toxicology consultation between January 2010 and June 2013. RESULTS: Of 3043 poisonings, 202 (7%) involved drug misuse (139 [69%] were males). Illicit drugs (primarily synthetic cannabinoids and "bath salts") were encountered in 101 (50%), followed by prescription medications (56 [28%]) and over-the-counter (OTC) drugs (51 [25%]). Dextromethorphan was the most commonly misused legal medication (24 [12%]). Polypharmacy exposure was documented in 74 (37%). One hundred sixty-three adolescents (81%) were symptomatic; of these, 81% had central nervous system impairments: psychosis (38%), agitation (30%), coma (26%), myoclonus (11%), and seizures (10%); and 66 (41%) displayed a specific toxidrome, most commonly sedative-hypnotic. Benzodiazepines were the most frequently administered medications (46%). Antidotes were administered to 28% of adolescents, primarily naloxone, physostigmine, N-acetyl-cysteine, and flumazenil. No deaths were recorded. CONCLUSIONS: Adolescents presenting with drug misuse may be exposed to a wide range and combinations of therapeutics or illicit substances and frequently display central nervous system abnormalities, compromising the ability to obtain a reliable history. Frontline clinicians should maintain a high index of suspicion, as routine toxicology screenings fail to detect most contemporary misused legal and designer drugs.

Occurrence of halogenated transformation products of selected pharmaceuticals and personal care products in secondary and tertiary treated wastewaters from southern California.

Final effluent samples from 10 southern California (United States) wastewater treatment facilities, employing four distinct treatment schemes, were surveyed for selected pharmaceuticals, personal care products (PPCPs), alkylphenols, and 21 of their halogenated disinfection byproducts. Chlorinated and brominated standards and isotopically labeled internal standards were synthesized and purified to confirm and more accurately quantify selected disinfection byproducts of salicylic acid, bisphenol A, gemfibrozil, naproxen, diclofenac, technical 4-nonylphenol, and 4-tert-octylphenol using high-performance liquid chromatography and tandem mass spectrometry. Concentrations of parent compounds ranged from <10 to 3830 ng/L (gemfibrozil), and those of chloro/bromo byproducts ranged from <4 to 370 ng/L (dibromo nonylphenol). The highest concentrations of parent compounds were measured in effluent that was not subjected to tertiary treatment. The chlorinated and brominated byproduct concentration may be affected by the influent concentration of parent compounds, hydraulic retention times, and chlorine contact times. Salicylic acid was readily halogenated, which is evident from the ratio of halogenated to nonhalogenated species. There were no measured chlorinated byproducts of bisphenol A despite occasionally high concentrations of the parent compound. Not surprisingly, higher concentrations of most brominated species were measured in the treatment plant with the highest bromide concentrations. These results demonstrate the occurrence of novel halogenated byproducts of PPCPs that have limited toxicological data and significant uncertainty with regard to their risk to ecological systems.

Neuroendocrine coupling across adolescence and the longitudinal influence of early life stress.

Drawing on conceptual models illustrating the advantages of a multisystemic, interactive, developmental approach to understanding development, the present study examines the covariation of stress and sex hormones across the adolescent transition and the effect of early life stress (ELS) on neuroendocrine coupling to gain insight into atypical development. Morning levels of cortisol, testosterone, and dehydroepiandrosterone (DHEA) were assessed at ages 11, 13, and 15; ELS was assessed during the infancy and preschool periods. Hierarchical linear modeling revealed that cortisol-DHEA coupling patterns progressed to tight, positive coupling across adolescence. Cortisol-testosterone coupling was positive at age 11 but became more negative at ages 13 and 15. Exposure to ELS resulted in more adultlike neuroendocrine coupling patterns earlier in life than non-exposed youth; however the effect of ELS on cortisol-testosterone coupling was unique to girls. Results illustrate trajectories of neuroendocrine coupling that may be unique to adolescence. Moderation by ELS suggests that early stress exposure may prompt earlier adultlike neuroendocrine coupling, particularly within girls, which may contribute to early pubertal development.

Adolescent internalizing symptoms and negative life events: the sensitizing effects of earlier life stress and cortisol.

Although adolescence is marked by increased negative life events and internalizing problems, few studies investigate this association as an ongoing longitudinal process. Moreover, while there are considerable individual differences in the degree to which these phenomena are linked, little is known about the origins of these differences. The present study examines early life stress (ELS) exposure and early-adolescent longitudinal afternoon cortisol level as predictors of the covariation between internalizing symptoms and negative life events across high school. ELS was assessed by maternal report during infancy, and the measure of cortisol was derived from assessments at ages 11, 13, and 15 years. Life events and internalizing symptoms were assessed at ages 15, 17, and 18 years. A two-level hierarchical linear model revealed that ELS and cortisol were independent predictors of the covariation of internalizing symptoms and negative life events. Compared to those with lower levels of ELS, ELS-exposed adolescents displayed tighter covariation between internalizing symptoms and negative life events. Adolescents with lower longitudinal afternoon cortisol displayed tighter covariation between negative life events and internalizing symptoms, while those with higher cortisol demonstrated weaker covariation, partially due to increased levels of internalizing symptoms when faced with fewer negative life events.

The symphonic structure of childhood stress reactivity: patterns of sympathetic, parasympathetic, and adrenocortical responses to psychological challenge.

Despite widespread recognition that the physiological systems underlying stress reactivity are well coordinated at a neurobiological level, surprisingly little empirical attention has been given to delineating precisely how the systems actually interact with one another when confronted with stress. We examined cross-system response proclivities in anticipation of and following standardized laboratory challenges in 664 4- to 14-year-olds from four independent studies. In each study, measures of stress reactivity within both the locus coeruleus-norepinephrine system (i.e., the sympathetic and parasympathetic branches of the autonomic nervous system) and the corticotrophin releasing hormone system (i.e., the hypothalamic-pituitary-adrenal axis) were collected. Latent profile analyses revealed six distinctive patterns that recurred across the samples: moderate reactivity (average cross-system activation; 52%-80% of children across samples), parasympathetic-specific reactivity (2%-36%), anticipatory arousal (4%-9%), multisystem reactivity (7%-14%), hypothalamic-pituitary-adrenal axis specific reactivity (6%-7%), and underarousal (0%-2%). Groups meaningfully differed in socioeconomic status, family adversity, and age. Results highlight the sample-level reliability of children's neuroendocrine responses to stress and suggest important cross-system regularities that are linked to development and prior experiences and may have implications for subsequent physical and mental morbidity.

Epigenetic vestiges of early developmental adversity: childhood stress exposure and DNA methylation in adolescence.

Fifteen-year-old adolescents (N = 109) in a longitudinal study of child development were recruited to examine differences in DNA methylation in relation to parent reports of adversity during the adolescents' infancy and preschool periods. Microarray technology applied to 28,000 cytosine-guanine dinucleotide sites within DNA derived from buccal epithelial cells showed differential methylation among adolescents whose parents reported high levels of stress during their children's early lives. Maternal stressors in infancy and paternal stressors in the preschool years were most strongly predictive of differential methylation, and the patterning of such epigenetic marks varied by children's gender. To the authors' knowledge, this is the first report of prospective associations between adversities in early childhood and the epigenetic conformation of adolescents' genomic DNA.

Analysis of the structural and mechanistic factors in antioxidants that preserve mitochondrial function and confer cytoprotection.

Selected pyridinol analogues of the experimental neuroprotective drug idebenone have been synthesized and evaluated as antioxidants capable of preserving mitochondrial function. The compounds, having a different redox core but the same side chain as idebenone, exhibited a range of potencies, reflecting differences in their structures. The results obtained provide guidance in the design of such analogues with improved properties. Analogues were identified that have significantly improved antioxidant activity compared with idebenone in cultured lymphocytes, and which exhibit lesser inhibition of the electron transport chain.

Longitudinal stability and developmental properties of salivary cortisol levels and circadian rhythms from childhood to adolescence.

This study aimed to (1) identify a stable, trait-like component to cortisol and its circadian rhythm, and (2) investigate individual differences in developmental trajectories of HPA-axis maturation. Multiple salivary cortisol samples were collected longitudinally across four assessments from age 9 (3rd grade) through age 15 (9th grade) in a community sample of children (N = 357). Sophisticated statistical models examined cortisol levels and its rhythm over time; effects of age, puberty and gender were primarily considered. In addition to situation-specific and stable short-term or epoch-specific cortisol components, there is a stable, trait-like component of cortisol levels and circadian rhythm across multiple years covering the transition from childhood into adolescence. Youth had higher cortisol and flatter circadian rhythms as they got older and more physically developed. Girls had higher cortisol, stronger circadian rhythms, and greater developmental influences across adolescence. Distinguishing a stable, trait-like component of cortisol level and its circadian rhythm provides the empirical foundation for investigating putative mechanisms underlying individual differences in HPA functioning. The findings also provide important descriptive information about maturational processes influencing HPA-axis development.

Early family context and development of adolescent ruminative style: moderation by temperament.

We know very little about the development of rumination, the tendency to passively brood about negative feelings. Because rumination is a risk factor for many forms of psychopathology, especially depression, such knowledge could prove important for preventing negative mental health outcomes in youth. This study examined developmental origins of rumination in a longitudinal sample (N=337; 51% girls) studied in preschool (ages 3½ and 4½ years) and early adolescence (ages 13 and 15 years). Results indicated that family context and child temperament, assessed during the preschool period, were risk factors for a ruminative style in adolescence. Specifically, early family contexts characterised by over-controlling parenting and a family style of negative-submissive expressivity predicted higher levels of later rumination. These associations were moderated by children's temperamental characteristics of negative affect and effortful control. Further, the interaction of these temperament factors exerted an additional influence on later rumination. Implications for prevention and intervention efforts are discussed.

Does oxidative stress contribute to the pathology of Friedreich's ataxia? A radical question.

Friedreich's ataxia (FRDA) is a hereditary neurodegenerative disease that frequently culminates in cardiac failure at an early age. FRDA is believed to arise from reduced synthesis of the mitochondrial iron chaperone frataxin due to impaired gene transcription, which leads to mitochondrial iron accumulation, dysfunction of mitochondrial Fe-S containing enzymes, and increased Fenton-mediated free radical production. Recent reports have challenged this generally accepted hypothesis, by suggesting that the oxidative stress component in FRDA is minimal and thereby questioning the benefit of antioxidant therapeutic strategies. We suggest that this apparent paradox results from the radically divergent chemistries of the participating reactive oxygen species (ROS), the major cellular subcompartments involved and the overall cellular responses to ROS. In this review, we consider these factors and conclude that oxidative stress does constitute a major contributing factor to FRDA pathology. This reaffirms the idea that the rational design of specific small molecule multifunctional antioxidants will benefit FRDA patients.

Behavioral and emotional symptoms of post-institutionalized children in middle childhood.

BACKGROUND: Experience in institutional/orphanage care has been linked to increased mental health problems. Research suggests that children adopted from institutions experience specific difficulties related to inattention/overactivity. Evidence of internalizing and conduct problems relative to non-adopted peers has been found in early childhood and early adolescence, but problems may not differ from other adopted children. This study clarifies the understanding of behavioral and emotional symptoms of post-institutionalized (PI) children during middle childhood. METHODS: Eight- to eleven-year-old PI children (n=68) and two comparison groups, children internationally adopted from foster care (n=74) and non-adopted children (n=76), and their parents completed the MacArthur Health and Behavior Questionnaire related to attention-deficit/hyperactivity disorder (ADHD), externalizing, and internalizing symptoms. Group means for symptom level and number of children with symptoms above clinical cutoffs were compared. RESULTS: PI children displayed an increased level of ADHD symptoms per parent report. PI child and parent report indicated a higher number of PI children above clinical ADHD cutoff. Both groups of internationally adopted (IA) children had higher levels of externalizing symptoms relative to non-adopted children, with parent report indicating higher numbers of IA children above the externalizing clinical threshold. Informants differed in their report of internalizing symptoms. Parents indicated that both IA groups displayed increased internalizing symptom levels and greater numbers above clinical threshold; however, children reported this to be true only for the PI group. CONCLUSIONS: PI children differ from non-adopted peers across symptom domains in middle childhood. Whether these concerns were more broadly associated with international adoption rather than institutional care depended on symptom domain and informant. An understanding of this variability may be beneficial for treatment and intervention.

Biological sensitivity to context moderates the effects of the early teacher-child relationship on the development of mental health by adolescence.

The moderating effects of biological sensitivity to context (physiological and behavioral stress reactivity) on the association between the early teacher-child relationship and the development of adolescent mental health problems were examined in a community sample of 96 children. Grade 1 measures of biological sensitivity to context included physiological (i.e., slope of mean arterial pressure across a 20- to 30-min stress protocol) and behavioral (i.e., temperamental inhibition/disinhibition) markers. Grade 1 measures of the teacher-child relationship included positive (i.e., closeness) and negative (i.e., conflict) qualities. Mental health symptoms were assessed at Grades 1 and 7. Results of a multiple regression analysis indicated substantial association of the teacher-child relationship with the development of adolescent mental health symptoms, especially for more reactive children. In addition to teacher-child relationship main effects, all four Reactivity x Teacher-Child Relationship interaction terms were statistically significant when controlling for Grade 1 symptom severity, suggesting that both physiological and behavioral reactivity moderate the association of both adverse and supportive aspects of the teacher-child relationship with Grade 7 symptom severity over and above Grade 1 severity. There were important differences, depending on which stress reactivity measure was considered. The importance of these findings for recent theoretical arguments regarding biological sensitivity to context and differential susceptibility is discussed.

Influence of early life stress on later hypothalamic-pituitary-adrenal axis functioning and its covariation with mental health symptoms: a study of the allostatic process from childhood into adolescence.

The hypothalamic-pituitary-adrenal (HPA) axis is a primary mechanism in the allostatic process through which early life stress (ELS) contributes to disease. Studies of the influence of ELS on children's HPA axis functioning have yielded inconsistent findings. To address this issue, the present study considers multiple types of ELS (maternal depression, paternal depression, and family expressed anger), mental health symptoms, and two components of HPA functioning (traitlike and epoch-specific activity) in a long-term prospective community study of 357 children. ELS was assessed during the infancy and preschool periods; mental health symptoms and cortisol were assessed at child ages 9, 11, 13, and 15 years. A three-level hierarchical linear model addressed questions regarding the influences of ELS on HPA functioning and its covariation with mental health symptoms. ELS influenced traitlike cortisol level and slope, with both hyper- and hypoarousal evident depending on type of ELS. Further, type(s) of ELS influenced covariation of epoch-specific HPA functioning and mental health symptoms, with a tighter coupling of HPA alterations with symptom severity among children exposed previously to ELS. Results highlight the importance of examining multiple types of ELS and dynamic HPA functioning in order to capture the allostatic process unfolding across the transition into adolescence.

A comparison of Cartesian-only vs. Cartesian-spherical hybrid coordinates for statistical shape modeling in the lumbar spine.

OBJECTIVE: The purpose of this study was to compare two methods for quantifying differences in geometric shapes of human lumbar vertebra using statistical shape modeling (SSM). METHODS: A novel 3D implementation of a previously published 2D, nonlinear SSM was implemented and compared to a commonly used, Cartesian method of SSM. The nonlinear method, or Hybrid SSM, and Cartesian SSM were applied to lumbar vertebra shapes from a cohort of 18 full lumbar triangle meshes derived from CT scans. The comparison included traditional metrics for cumulative variance, generality, and specificity and results from application-based biomechanics using finite element simulation. RESULTS: The Hybrid SSM has less compactness - likely due to the increased number of mathematical constraints in the SSM formulation. Similar results were found between methods for specificity and generality. Compared to the previously validated, manually-segmented FE model, both SSM methods produced similar and agreeable results. CONCLUSION: Visual, statistical, and biomechanical findings did not convincingly support the superiority of the Hybrid SSM over the simpler Cartesian SSM. SIGNIFICANCE: This work suggests that, of the two methods compared, the Cartesian SSM is adequate to capture the variations in shape of the posterior spinal structures for biomechanical modeling applications.

Design, synthesis, and evaluation of an α-tocopherol analogue as a mitochondrial antioxidant.

An efficient synthesis has provided access to a novel α-tocopherol analogue (2), as well as its trifluoroacetate salt and acetate ester. An annulation reaction was used to establish the pyridinol core structure and a Stille coupling reaction was employed for conjugation with the tocopherol side chain. This analogue was shown to suppress the levels of reactive oxygen species in cultured cells, and to quench peroxidation of mitochondrial membranes.

Sex Differences in the Relationship Between Childhood Self-Regulation and Adolescent Adiposity.

OBJECTIVE: Research suggests that higher childhood self-regulation (CSR) predicts lower adiposity in adolescence. However, it is unclear whether this relationship differs by sex or by baseline weight status. Thus, this study investigated these questions in a longitudinal, community-based cohort. METHODS: The cohort included 221 girls and 214 boys. At age 9, CSR was assessed via parent/teacher reports of effortful control, and childhood BMI z scores (BMIz) were calculated from staff measurements. Late-adolescent waist-to-height ratio was based on staff measurements at age 18. RESULTS: CSR has a small inverse correlation with concurrent childhood BMIz in girls, but not in boys. Prospectively, however, CSR has a small inverse association with late-adolescent weight-to-height ratio in both sexes, after adjusting for childhood BMIz and other childhood predictors. This prospective association is marginally stronger for girls with higher (vs. lower) childhood BMIz. CONCLUSIONS: CSR inversely predicts changes in adiposity across adolescence in both sexes, with some evidence that this association is stronger for girls with higher (vs. lower) childhood adiposity. However, this inverse association between CSR and adiposity may emerge earlier in girls. Future research should examine the causal status of CSR and its relationship to behaviors (e.g., diet).

Gender differences in emotional reactivity of depressed and at-risk preschoolers: implications for gender specific manifestations of preschool depression.

We investigated whether differences in positive and negative emotional reactivity could be found in depressed preschoolers and preschoolers at risk for later internalizing symptoms relative to nondepressed/low risk comparison groups. Observational measures of emotional reactivity, used to derive a score of the balance between anger and sadness, were obtained and analyzed in independent samples. One study utilized cross-sectional data from preschoolers (M age = 4.6 years) with a current depressive syndrome and two nondepressed comparison groups. The other study utilized longitudinal data that assessed emotional reactivity at preschool age (M age = 4.5 years) and later mental health symptoms during the transition to primary school, allowing a retrospective determination of risk. Depressed and at-risk boys displayed more anger than sadness in contrast to girls in the same groups and in contrast to no disorder/low-risk controls. This finding was detected in depressed and "at risk for internalizing" boys who were not comorbid for externalizing problems.

Mitochondria-directed therapeutics.

Mitochondria are key regulators of cell life and death and play an important role in a wide range of diseases, including cancer, diabetes, cardiovascular disease, and the age-related neurodegenerative diseases. The unique structural and functional characteristics of mitochondria enable the selective targeting of drugs designed to modulate the function of this organelle for therapeutic gain. This forum discusses (a) potential new mitochondrial targets for therapeutic intervention, including components of the electron transport chain, the permeability transition, and the membrane dynamics protein mitofusin-2; (b) the role of mitochondria-targeted antioxidants including MitoQ and SS peptides in modulating reactive oxygen and chlorine species induced mitochondrial permeabilization and cell death; and (c) the potential use of SS peptides in ischemia and reperfusion tissue injury. In the future, mitochondrial drug-targeting strategies will be expected to open up avenues for manipulating mitochondrial functions and allow for selective protection or eradication of cells for therapeutic gain in a variety of diseases.