Molecular variation at the SLC6A3 locus predicts lifetime risk of PTSD in the Detroit Neighborhood Health Study

Recent work suggests that the 9-repeat (9R) allele located in the 3'UTR VNTR of the SLC6A3 gene increases risk of posttraumatic stress disorder (PTSD). However, no study reporting this association to date has been based on population-based samples. Furthermore, no study of which we are aware has assessed the joint action of genetic and DNA methylation variation at SLC6A3 on risk of PTSD. In this study, we assessed whether molecular variation at SLC6A3 locus influences risk of PTSD. Participants (n = 320; 62 cases/258 controls) were drawn from an urban, community-based sample of predominantly African American Detroit adult residents, and included those who had completed a baseline telephone survey, had provided blood specimens, and had a homozygous genotype for either the 9R or 10R allele or a heterozygous 9R/10R genotype. The influence of DNA methylation variation in the SLC6A3 promoter locus was also assessed in a subset of participants with available methylation data (n = 83; 16 cases/67 controls). In the full analytic sample, 9R allele carriers had almost double the risk of lifetime PTSD compared to 10R/10R genotype carriers (OR = 1.98, 95% CI = 1.02-3.86), controlling for age, sex, race, socioeconomic status, number of traumas, smoking, and lifetime depression. In the subsample of participants with available methylation data, a significant (p = 0.008) interaction was observed whereby 9R allele carriers showed an increased risk of lifetime PTSD only in conjunction with high methylation in the SLC6A3 promoter locus, controlling for the same covariates. Our results confirm previous reports supporting a role for the 9R allele in increasing susceptibility to PTSD. They further extend these findings by providing preliminary evidence that a "double hit" model, including both a putatively reduced-function allele and high methylation in the promoter region, may more accurately capture molecular risk of PTSD at the SLC6A3 locus.

Dynamic gene expression in the human cerebral cortex distinguishes children from adults

In comparison with other primate species, humans have an extended juvenile period during which the brain is more plastic. In the current study we sought to examine gene expression in the cerebral cortex during development in the context of this adaptive plasticity. We introduce an approach designed to discriminate genes with variable as opposed to uniform patterns of gene expression and found that greater inter-individual variance is observed among children than among adults. For the 337 transcripts that show this pattern, we found a significant overrepresentation of genes annotated to the immune system process (pFDR≅0). Moreover, genes known to be important in neuronal function, such as brain-derived neurotrophic factor (BDNF), are included among the genes more variably expressed in childhood. We propose that the developmental period of heightened childhood neuronal plasticity is characterized by more dynamic patterns of gene expression in the cerebral cortex compared to adulthood when the brain is less plastic. That an overabundance of these genes are annotated to the immune system suggests that the functions of these genes can be thought of not only in the context of antigen processing and presentation, but also in the context of nervous system development.

Child maltreatment increases sensitivity to adverse social contexts: neighborhood physical disorder and incident binge drinking in Detroit

INTRODUCTION

Exposure to child maltreatment is associated with elevated risk for behavioral disorders in adulthood. One explanation for this life-course association is that child maltreatment increases vulnerability to the effects of subsequent stressors; however, the extent to which maltreatment increases sensitivity to social context has never been examined. We evaluated whether the association between neighborhood physical disorder and binge drinking was modified by child maltreatment exposure.

METHODS

Data were drawn from the Detroit Neighborhood Health Study, a prospective representative sample of predominately African Americans in the Detroit population. Neighborhood physical disorder was measured via systematic neighborhood assessment. Child maltreatment indicators included self-reported physical, sexual, and emotional abuse. Incident binge drinking was defined as at least one episode of ≥5 drinks (men) or ≥4 drinks (women) in the past 30-day period among those with no binge drinking at baseline (N=1013).

RESULTS

Child maltreatment and neighborhood physical disorder interacted to predict incident binge drinking (B=0.16, p=0.02) and maximum number of past 30-day drinks (B=0.15, p=0.04), such that neighborhood physical disorder predicted problematic alcohol use only among individuals with high exposure to child maltreatment.

CONCLUSION

The results add to the growing literature that African Americans in the US are exposed to an array of stressors that have pernicious consequences for problematic alcohol use. Our results document the need for increased attention to the potential for at-risk alcohol use among populations with a high degree of stress exposure.

Facemasks, hand hygiene, and influenza among young adults: a randomized intervention trial

Limited vaccine availability and the potential for resistance to antiviral medications have led to calls for establishing the efficacy of non-pharmaceutical measures for mitigating pandemic influenza. Our objective was to examine if the use of face masks and hand hygiene reduced rates of influenza-like illness (ILI) and laboratory-confirmed influenza in the natural setting. A cluster-randomized intervention trial was designed involving 1,178 young adults living in 37 residence houses in 5 university residence halls during the 2007–2008 influenza season. Participants were assigned to face mask and hand hygiene, face mask only, or control group during the study. Discrete-time survival models using generalized estimating equations to estimate intervention effects on ILI and confirmed influenza A/B infection over a 6-week study period were examined. A significant reduction in the rate of ILI was observed in weeks 3 through 6 of the study, with a maximum reduction of 75% during the final study week (rate ratio [RR] = 0.25, [95% CI, 0.07 to 0.87]). Both intervention groups compared to the control showed cumulative reductions in rates of influenza over the study period, although results did not reach statistical significance. Generalizability limited to similar settings and age groups. Face masks and hand hygiene combined may reduce the rate of ILI and confirmed influenza in community settings. These non-pharmaceutical measures should be recommended in crowded settings at the start of an influenza pandemic.

Pervasive exposure to violence and posttraumatic stress disorder in a predominantly African American Urban Community: the Detroit Neighborhood Health Study

Exposure to traumatic events is common, particularly among economically disadvantaged, urban African Americans. There is, however, scant data on the psychological consequences of exposure to traumatic events in this group. We assessed experience with traumatic events and posttraumatic stress disorder (PTSD) among 1,306 randomly selected, African American residents of Detroit. Lifetime prevalence of exposure to at least 1 traumatic event was 87.2% (assault = 51.0%). African Americans from Detroit have a relatively high burden of PTSD; 17.1% of those who experienced a traumatic event met criteria for probable lifetime PTSD. Assaultive violence is pervasive and is more likely to be associated with subsequent PTSD than other types of events. Further efforts to prevent violence and increase access to mental health treatment could reduce the mental health burden in economically disadvantaged urban areas.

Research review: gene-environment interaction research in youth depression - a systematic review with recommendations for future research

BACKGROUND

Depression is a major public health problem among youth, currently estimated to affect as many as 9% of US children and adolescents. The recognition that both genes (nature) and environments (nurture) are important for understanding the etiology of depression has led to a rapid growth in research exploring gene-environment interactions (GxE). However, there has been no systematic review of GxE in youth depression to date.

METHODS

The goal of this article was to systematically review evidence on the contribution of GxE to the risk of child and adolescent depression. Through a search of PubMed and PsycINFO databases to 1 April 2010, we identified 20 candidate gene-environment interaction studies focused on depression in youth (up to age 26) and compared each study in terms of the following characteristics: research design and sample studied; measure of depression and environment used; genes explored; and GxE findings in relation to these factors.

RESULTS

In total, 80% of studies (n = 16) found at least one significant GxE association. However, there was wide variation in methods and analyses adopted across studies, especially with respect to environmental measures used and tests conducted to estimate GxE. This heterogeneity made it difficult to compare findings and evaluate the strength of the evidence for GxE.

CONCLUSIONS

The existing body of GxE research on depression in youth contains studies that are conceptually and methodologically quite different, which contributes to mixed findings and makes it difficult to assess the current state of the evidence. To decrease this heterogeneity, we offer 20 recommendations that are focused on: (a) reporting GxE research; (b) testing and reporting GxE effects; (c) conceptualizing, measuring and analyzing depression; (d) conceptualizing, measuring and analyzing environment; (e) increasing power to test for GxE; and (f) improving the quality of genetic data used. Although targeted to GxE research on depression, these recommendations can be adopted by GxE researchers focusing on other mental health outcomes.

How does the social environment 'get into the mind'? Epigenetics at the intersection of social and psychiatric epidemiology

The social environment plays a considerable role in determining major psychiatric disorders. Emerging evidence suggests that features of the social environment modify gene expression independently of the primary DNA sequence through epigenetic processes. Accordingly, dysfunction of epigenetic mechanisms offers a plausible mechanism by which an adverse social environment gets "into the mind" and results in poor mental health. The purpose of this review is to provide an overview of the studies suggesting that epigenetic changes introduced by the social environment then manifest as psychological consequences. Our goal is to build a platform to discuss the ways in which future epidemiologic studies may benefit from including epigenetic measures. We focus on schizophrenia, major depressive disorder, post-traumatic stress disorder, anorexia nervosa, and substance dependence as examples that highlight the ways in which social environmental exposures, mediated through epigenetic processes, affect mental health.

Silencing, positive selection and parallel evolution: busy history of primate cytochromes C

Cytochrome c (cyt c) participates in two crucial cellular processes, energy production and apoptosis, and unsurprisingly is a highly conserved protein. However, previous studies have reported for the primate lineage (i) loss of the paralogous testis isoform, (ii) an acceleration and then a deceleration of the amino acid replacement rate of the cyt c somatic isoform, and (iii) atypical biochemical behavior of human cyt c. To gain insight into the cause of these major evolutionary events, we have retraced the history of cyt c loci among primates. For testis cyt c, all primate sequences examined carry the same nonsense mutation, which suggests that silencing occurred before the primates diversified. For somatic cyt c, maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses yielded the same tree topology. The evolutionary analyses show that a fast accumulation of non-synonymous mutations (suggesting positive selection) occurred specifically on the anthropoid lineage root and then continued in parallel on the early catarrhini and platyrrhini stems. Analysis of evolutionary changes using the 3D structure suggests they are focused on the respiratory chain rather than on apoptosis or other cyt c functions. In agreement with previous biochemical studies, our results suggest that silencing of the cyt c testis isoform could be linked with the decrease of primate reproduction rate. Finally, the evolution of cyt c in the two sister anthropoid groups leads us to propose that somatic cyt c evolution may be related both to COX evolution and to the convergent brain and body mass enlargement in these two anthropoid clades.

Spontaneous abortion and preterm labor and delivery in nonhuman primates: evidence from a captive colony of chimpanzees (Pan troglodytes)

BACKGROUND

Preterm birth is a leading cause of perinatal mortality, yet the evolutionary history of this obstetrical syndrome is largely unknown in nonhuman primate species.

METHODOLOGY/PRINCIPAL FINDINGS

We examined the length of gestation during pregnancies that occurred in a captive chimpanzee colony by inspecting veterinary and behavioral records spanning a total of thirty years. Upon examination of these records we were able to confidently estimate gestation length for 93 of the 97 (96%) pregnancies recorded at the colony. In total, 78 singleton gestations resulted in live birth, and from these pregnancies we estimated the mean gestation length of normal chimpanzee pregnancies to be 228 days, a finding consistent with other published reports. We also calculated that the range of gestation in normal chimpanzee pregnancies is approximately forty days. Of the remaining fifteen pregnancies, only one of the offspring survived, suggesting viability for chimpanzees requires a gestation of approximately 200 days. These fifteen pregnancies constitute spontaneous abortions and preterm deliveries, for which the upper gestational age limit was defined as 2 SD from the mean length of gestation (208 days).

CONCLUSIONS/SIGNIFICANCE

The present study documents that preterm birth occurred within our study population of captive chimpanzees. As in humans, pregnancy loss is not uncommon in chimpanzees, In addition, our findings indicate that both humans and chimpanzees show a similar range of normal variation in gestation length, suggesting this was the case at the time of their last common ancestor (LCA). Nevertheless, our data suggest that whereas chimpanzees' normal gestation length is ∼20-30 days after reaching viability, humans' normal gestation length is approximately 50 days beyond the estimated date of viability without medical intervention. Future research using a comparative evolutionary framework should help to clarify the extent to which mechanisms at work in normal and preterm parturition are shared in these species.

Reconstructing an icosahedral virus from single-particle diffraction experiments

The first experimental data from single-particle scattering experiments from free electron lasers (FELs) are now becoming available. The first such experiments are being performed on relatively large objects such as viruses, which produce relatively low-resolution, low-noise diffraction patterns in so-called "diffract-and-destroy" experiments. We describe a very simple test on the angular correlations of measured diffraction data to determine if the scattering is from an icosahedral particle. If this is confirmed, the efficient algorithm proposed can then combine diffraction data from multiple shots of particles in random unknown orientations to generate a full 3D image of the icosahedral particle. We demonstrate this with a simulation for the satellite tobacco necrosis virus (STNV), the atomic coordinates of whose asymmetric unit is given in Protein Data Bank entry 2BUK.

Gene expression and methylation signatures of MAN2C1 are associated with PTSD

As potential regulators of DNA accessibility and activity, epigenetic modifications offer a mechanism by which the environment can moderate the effects of genes. To date, however, there have been relatively few studies assessing epigenetic modifications associated with post-traumatic stress disorder (PTSD). Here we investigate PTSD-associated methylation differences in 33 genes previously shown to differ in whole blood-derived gene expression levels between those with vs. without the disorder. Drawing on DNA samples similarly obtained from whole blood in 100 individuals, 23 with and 77 without lifetime PTSD, we used methylation microarray data to assess whether these 33 candidate genes showed epigenetic signatures indicative of increased risk for, or resilience to, PTSD. Logistic regression analyses were performed to assess the main and interacting effects of candidate genes’ methylation values and number of potentially traumatic events (PTEs), adjusting for age and other covariates. Results revealed that only one candidate gene–MAN2C1–showed a significant methylation x PTE interaction, such that those with both higher MAN2C1 methylation and greater exposure to PTEs showed a marked increase in risk of lifetime PTSD (OR 4.35, 95% CI: 1.07, 17.77, p = 0.04). These results indicate that MAN2C1 methylation levels modify cumulative traumatic burden on risk of PTSD, and suggest that both gene expression and epigenetic changes at specific loci are associated with this disorder.

SLC6A4 methylation modifies the effect of the number of traumatic events on risk for posttraumatic stress disorder

BACKGROUND

Posttraumatic stress disorder (PTSD) is a common and debilitating mental disorder that occurs following exposure to a traumatic event. However, most individuals do not develop PTSD following even a severe trauma, leading to a search for new variables, such as genetic and other molecular variation, associated with vulnerability and resilience in the face of trauma exposure.

METHOD

We examined whether serotonin transporter (SLC6A4) promoter genotype and methylation status modified the association between number of traumatic events experienced and PTSD in a subset of 100 individuals from the Detroit Neighborhood Health Study.

RESULTS

Number of traumatic events was strongly associated with risk of PTSD. Neither SLC6A4 genotype nor methylation status was associated with PTSD in main effects models. However, SLC6A4 methylation levels modified the effect of the number of traumatic events on PTSD after controlling for SLC6A4 genotype. Persons with more traumatic events were at increased risk for PTSD, but only at lower methylation levels. At higher methylation levels, individuals with more traumatic events were protected from this disorder. This interaction was observed whether the outcome was PTSD diagnosis, symptom severity, or number of symptoms.

CONCLUSIONS

Gene-specific methylation patterns may offer potential molecular signatures of increased risk for and resilience to PTSD.

Epigenetic and inflammatory marker profiles associated with depression in a community-based epidemiologic sample

BACKGROUND

Recent work suggests that epigenetic differences may be associated with psychiatric disorders. Here we investigate, in a community-based sample, whether methylation profiles distinguish between individuals with and without lifetime depression. We also investigate the physiologic consequences that may be associated with these profiles.

METHOD

Using whole blood-derived genomic DNA from a subset of participants in the Detroit Neighborhood Health Study (DNHS), we applied methylation microarrays to assess genome-wide methylation profiles for over 14 000 genes in 33 persons who reported a lifetime history of depression and 67 non-depressed adults. Bioinformatic functional analyses were performed on the genes uniquely methylated and unmethylated in each group, and inflammatory biomarkers [interleukin (IL)-6 and C-reactive protein (CRP)] were measured to investigate the possible functional significance of the methylation profiles observed.

RESULTS

Uniquely unmethylated gene sets distinguished between those with versus without lifetime depression. In particular, some processes (e.g. brain development, tryptophan metabolism) showed patterns suggestive of increased methylation among individuals with depression whereas others (e.g. lipoprotein) showed patterns suggestive of decreased methylation among individuals with depression. IL-6 and CRP levels were elevated among those with lifetime depression and, among those with depression only, IL-6 methylation showed an inverse correlation with circulating IL-6 and CRP.

CONCLUSIONS

Genome-wide methylation profiles distinguish individuals with versus without lifetime depression in a community-based setting, and show coordinated signals with pathophysiological mechanisms previously implicated in the etiology of this disorder. Examining epigenetic mechanisms in concert with other dynamic markers of physiologic functioning should improve our understanding of the neurobiology of depression.

The urban environment and mental disorders: Epigenetic links

For the first time in human history, more than half of the world's population lives in urban areas and this is projected to increase to two-thirds by 2030. This increased urbanity of the world's population has substantial public health implications. Nearly a century of research has shown higher risk of mental disorder among persons living in urban versus rural areas. Epidemiologic research has documented that associations between particular features of the urban environment, such as concentrated disadvantage, residential segregation and social norms, contribute to the risk of mental illness. We propose that changes in DNA methylation may be one potential mechanism through which features of the urban environment contribute to psychopathology. Recent advances in animal models and human correlation studies suggest DNA methylation as a promising mechanism that can explain how the environment "gets under the skin." Aberrant DNA methylation signatures characterize mental disorders in community settings. Emerging evidence of associations between exposure to features of the environment and methylation patterns may lead toward the identification of mechanisms that explain the link between urban environments and mental disorders. Importantly, evidence that epigenetic changes are reversible offers new opportunities for ameliorating the impact of adverse urban environments on human health.

Stress, adherence to preventive measures for reducing influenza transmission and influenza-like illness

BACKGROUND

Using data from a randomised intervention trial of facemask use and hand hygiene for reducing transmission of seasonal influenza among university students, we examined if levels of perceived stress were negatively associated with adherence to these preventive measures and incidence of influenza-like illness (ILI).

METHODS

Longitudinal analyses using generalised estimating equations were examined. Perceived stress was self-reported at baseline using a validated scale. Compliance with preventive measures was self-reported throughout the study period and reported ILI symptoms were defined as cough and one or more of fever/feverishness, chills and body aches.

RESULTS

Higher levels of perceived stress were not associated with facemask or hand hygiene compliance. However, perceived stress was significantly associated with a greater ILI incidence (HR1.25, 95% CI 1.07 to 1.45) even after controlling for demographic and behavioural risk factors.

CONCLUSIONS

Among students in the university setting, higher levels of perceived stress affect ILI symptom reporting but not compliance with preventive measures for reducing transmission of influenza. Further studies are needed to examine whether psychological stress is a key mechanism explaining socio-demographic health disparities in confirmed influenza infection among healthy persons in the community setting.

Caesarean of Lion (Panthera leo) at Dulahajra Safari Park, Bangladesh

A six years eight months pregnant lioness at the Dulahajara Safari Park, Chakoria, Cox�s Bazar, Bangladesh, was presented with dystocia. This paper described the pre-, intra- and postoperative procedures including anesthetic protocol carried out and performing a caesarean section to remove dead fetuses and the successful recovery of the lioness without complications.

Gender differences in the genetic and environmental determinants of adolescent depression

BACKGROUND

The well-documented gender differences in the risk for depression may be explained by genetic factors, by different responses to social context, or by a combination of both. We sought to assess whether there were gender differences in the longitudinal associations between serotonin transporter promoter (5-HTTLPR) genotype and depressive symptoms in adolescents, and whether macrosocial context plays a role in explaining any observed differences.

METHODS

Using data from a nationally representative survey of adolescents, we applied multilevel mixed models to assess, separately for adolescent males and females (a) the relation between 5-HTTLPR genotype and depressive symptoms and (b) the interaction of county-level deprivation and 5-HTTLPR genotype in models predicting depressive symptoms. All models adjusted for age and other covariates.

RESULTS

Among females (n=560), main effects models showed an association between the sl genotype and lowered risk of depressive symptoms (b=-.18, P=.03). Among males (n=524), interaction models showed an association between sl genotype and lowered risk of depressive symptoms in deprived counties only (b=-.32, P=.04).

CONCLUSIONS

In adolescent females, the 5-HTTLPR sl genotype confers protection against depressive symptoms independent of county-level social context, whereas in adolescent males, protection by the same genotype is conferred only within the context of county-level deprivation. Future work should aim to understand how genetic and macrosocial factors jointly shape risk for mental illness, and how these factors shape gender differences in mental illness.

Research findings from nonpharmaceutical intervention studies for pandemic influenza and current gaps in the research

In June 2006, the Centers for Disease Control and Prevention released a request for applications to identify, improve, and evaluate the effectiveness of nonpharmaceutical interventions (NPIs)-strategies other than vaccines and antiviral medications-to mitigate the spread of pandemic influenza within communities and across international borders (RFA-CI06-010). These studies have provided major contributions to seasonal and pandemic influenza knowledge. Nonetheless, key concerns were identified related to the acceptability and protective efficacy of NPIs. Large-scale intervention studies conducted over multiple influenza epidemics, as well as smaller studies in controlled laboratory settings, are needed to address the gaps in the research on transmission and mitigation of influenza in the community setting. The current novel influenza A (H1N1) pandemic underscores the importance of influenza research.

Mask use, hand hygiene, and seasonal influenza-like illness among young adults: A randomized intervention trial

Background . During the influenza A(H1N1) pandemic, antiviral prescribing was limited, vaccines were not available early, and the effectiveness of nonpharmaceutical interventions (NPIs) was uncertain. Our study examined whether use of face masks and hand hygiene reduced the incidence of influenza-like illness (ILI).

Methods . A randomized intervention trial involving 1437 young adults living in university residence halls during the 2006–2007 influenza season was designed. Residence halls were randomly assigned to 1 of 3 groups—face mask use, face masks with hand hygiene, or control— for 6 weeks. Generalized models estimated rate ratios for clinically diagnosed or survey-reported ILI weekly and cumulatively.

Results . We observed significant reductions in ILI during weeks 4–6 in the mask and hand hygiene group, compared with the control group, ranging from 35% (confidence interval [CI], 9%–53%) to 51% (CI, 13%–73%), after adjusting for vaccination and other covariates. Face mask use alone showed a similar reduction in ILI compared with the control group, but adjusted estimates were not statistically significant. Neither face mask use and hand hygiene nor face mask use alone was associated with a significant reduction in the rate of ILI cumulatively.

Conclusions . These findings suggest that face masks and hand hygiene may reduce respiratory illnesses in shared living settings and mitigate the impact of the influenza A(H1N1) pandemic.

Trial Registration . ClinicalTrials.gov identifier: NCT00490633.