Genome-wide association analyses identify 95 risk loci and provide insights into the neurobiology of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) genetics are characterized by lower discoverability than most other psychiatric disorders. The contribution to biological understanding from previous genetic studies has thus been limited. We performed a multi-ancestry meta-analysis of genome-wide association studies across 1,222,882 individuals of European ancestry (137,136 cases) and 58,051 admixed individuals with African and Native American ancestry (13,624 cases). We identified 95 genome-wide significant loci (80 new). Convergent multi-omic approaches identified 43 potential causal genes, broadly classified as neurotransmitter and ion channel synaptic modulators (for example, GRIA1, GRM8 and CACNA1E), developmental, axon guidance and transcription factors (for example, FOXP2, EFNA5 and DCC), synaptic structure and function genes (for example, PCLO, NCAM1 and PDE4B) and endocrine or immune regulators (for example, ESR1, TRAF3 and TANK). Additional top genes influence stress, immune, fear and threat-related processes, previously hypothesized to underlie PTSD neurobiology. These findings strengthen our understanding of neurobiological systems relevant to PTSD pathophysiology, while also opening new areas for investigation.

Common genetic variation impacts stress response in the brain

To explain why individuals exposed to identical stressors experience divergent clinical outcomes, we determine how molecular encoding of stress modifies genetic risk for brain disorders. Analysis of post-mortem brain (n=304) revealed 8557 stress-interactive expression quantitative trait loci (eQTLs) that dysregulate expression of 915 eGenes in response to stress, and lie in stress-related transcription factor binding sites. Response to stress is robust across experimental paradigms: up to 50% of stress-interactive eGenes validate in glucocorticoid treated hiPSC-derived neurons (n=39 donors). Stress-interactive eGenes show brain region- and cell type-specificity, and, in post-mortem brain, implicate glial and endothelial mechanisms. Stress dysregulates long-term expression of disorder risk genes in a genotype-dependent manner; stress-interactive transcriptomic imputation uncovered 139 novel genes conferring brain disorder risk only in the context of traumatic stress. Molecular stress-encoding explains individualized responses to traumatic stress; incorporating trauma into genomic studies of brain disorders is likely to improve diagnosis, prognosis, and drug discovery.

Discovery of 95 PTSD loci provides insight into genetic architecture and neurobiology of trauma and stress-related disorders

Posttraumatic stress disorder (PTSD) genetics are characterized by lower discoverability than most other psychiatric disorders. The contribution to biological understanding from previous genetic studies has thus been limited. We performed a multi-ancestry meta-analysis of genome-wide association studies across 1,222,882 individuals of European ancestry (137,136 cases) and 58,051 admixed individuals with African and Native American ancestry (13,624 cases). We identified 95 genome-wide significant loci (80 novel). Convergent multi-omic approaches identified 43 potential causal genes, broadly classified as neurotransmitter and ion channel synaptic modulators (e.g., GRIA1, GRM8, CACNA1E ), developmental, axon guidance, and transcription factors (e.g., FOXP2, EFNA5, DCC ), synaptic structure and function genes (e.g., PCLO, NCAM1, PDE4B ), and endocrine or immune regulators (e.g., ESR1, TRAF3, TANK ). Additional top genes influence stress, immune, fear, and threat-related processes, previously hypothesized to underlie PTSD neurobiology. These findings strengthen our understanding of neurobiological systems relevant to PTSD pathophysiology, while also opening new areas for investigation.

Decoding Shared Versus Divergent Transcriptomic Signatures Across Cortico-Amygdala Circuitry in PTSD and Depressive Disorders

OBJECTIVE

Posttraumatic stress disorder (PTSD) is a debilitating neuropsychiatric disease that is highly comorbid with major depressive disorder (MDD) and bipolar disorder. The overlap in symptoms is hypothesized to stem from partially shared genetics and underlying neurobiological mechanisms. To delineate conservation between transcriptional patterns across PTSD and MDD, the authors examined gene expression in the human cortex and amygdala in these disorders.

METHODS

RNA sequencing was performed in the postmortem brain of two prefrontal cortex regions and two amygdala regions from donors diagnosed with PTSD (N=107) or MDD (N=109) as well as from neurotypical donors (N=109).

RESULTS

The authors identified a limited number of differentially expressed genes (DEGs) specific to PTSD, with nearly all mapping to cortical versus amygdala regions. PTSD-specific DEGs were enriched in gene sets associated with downregulated immune-related pathways and microglia as well as with subpopulations of GABAergic inhibitory neurons. While a greater number of DEGs associated with MDD were identified, most overlapped with PTSD, and only a few were MDD specific. The authors used weighted gene coexpression network analysis as an orthogonal approach to confirm the observed cellular and molecular associations.

CONCLUSIONS

These findings provide supporting evidence for involvement of decreased immune signaling and neuroinflammation in MDD and PTSD pathophysiology, and extend evidence that GABAergic neurons have functional significance in PTSD.

Enhancing Discovery of Genetic Variants for Posttraumatic Stress Disorder Through Integration of Quantitative Phenotypes and Trauma Exposure Information

BACKGROUND

Posttraumatic stress disorder (PTSD) is heritable and a potential consequence of exposure to traumatic stress. Evidence suggests that a quantitative approach to PTSD phenotype measurement and incorporation of lifetime trauma exposure (LTE) information could enhance the discovery power of PTSD genome-wide association studies (GWASs).

METHODS

A GWAS on PTSD symptoms was performed in 51 cohorts followed by a fixed-effects meta-analysis (N = 182,199 European ancestry participants). A GWAS of LTE burden was performed in the UK Biobank cohort (N = 132,988). Genetic correlations were evaluated with linkage disequilibrium score regression. Multivariate analysis was performed using Multi-Trait Analysis of GWAS. Functional mapping and annotation of leading loci was performed with FUMA. Replication was evaluated using the Million Veteran Program GWAS of PTSD total symptoms.

RESULTS

GWASs of PTSD symptoms and LTE burden identified 5 and 6 independent genome-wide significant loci, respectively. There was a 72% genetic correlation between PTSD and LTE. PTSD and LTE showed largely similar patterns of genetic correlation with other traits, albeit with some distinctions. Adjusting PTSD for LTE reduced PTSD heritability by 31%. Multivariate analysis of PTSD and LTE increased the effective sample size of the PTSD GWAS by 20% and identified 4 additional loci. Four of these 9 PTSD loci were independently replicated in the Million Veteran Program.

CONCLUSIONS

Through using a quantitative trait measure of PTSD, we identified novel risk loci not previously identified using prior case-control analyses. PTSD and LTE have a high genetic overlap that can be leveraged to increase discovery power through multivariate methods.

Gene expression in the dorsolateral and ventromedial prefrontal cortices implicates immune-related gene networks in PTSD

Studies evaluating neuroimaging, genetically predicted gene expression, and pre-clinical genetic models of PTSD, have identified PTSD-related abnormalities in the prefrontal cortex (PFC) of the brain, particularly in dorsolateral and ventromedial PFC (dlPFC and vmPFC). In this study, RNA sequencing was used to examine gene expression in the dlPFC and vmPFC using tissue from the VA National PTSD Brain Bank in donors with histories of PTSD with or without depression (dlPFC n = 38, vmPFC n = 35), depression cases without PTSD (n = 32), and psychopathology-free controls (dlPFC n = 24, vmPFC n = 20). Analyses compared PTSD cases to controls. Follow-up analyses contrasted depression cases to controls. Twenty-one genes were differentially expressed in PTSD after strict multiple testing correction. PTSD-associated genes with roles in learning and memory (FOS, NR4A1), immune regulation (CFH, KPNA1) and myelination (MBP, MOBP, ERMN) were identified. PTSD-associated genes partially overlapped depression-associated genes. Co-expression network analyses identified PTSD-associated networks enriched for immune-related genes across the two brain regions. However, the immune-related genes and association patterns were distinct. The immune gene IL1B was significantly associated with PTSD in candidate-gene analysis and was an upstream regulator of PTSD-associated genes in both regions. There was evidence of replication of dlPFC associations in an independent cohort from a recent study, and a strong correlation between the dlPFC PTSD effect sizes for significant genes in the two studies (r = 0.66, p < 2.2 × 10⁻¹⁶). In conclusion, this study identified several novel PTSD-associated genes and brain region specific PTSD-associated immune-related networks.

STRONG STAR and the Consortium to Alleviate PTSD: Shaping the future of combat PTSD and related conditions in military and veteran populations

The STRONG STAR Consortium (South Texas Research Organizational Network Guiding Studies on Trauma and Resilience) and the Consortium to Alleviate PTSD are interdisciplinary and multi-institutional research consortia focused on the detection, diagnosis, prevention, and treatment of combat-related posttraumatic stress disorder (PTSD) and comorbid conditions in military personnel and veterans. This manuscript outlines the consortia's state-of-the-science collaborative research model and how this can be used as a roadmap for future trauma-related research. STRONG STAR was initially funded for 5 years in 2008 by the U.S. Department of Defense's (DoD) Psychological Health and Traumatic Brain Injury Research Program. Since the initial funding of STRONG STAR, almost 50 additional peer-reviewed STRONG STAR-affiliated projects have been funded through the DoD, the U.S. Department of Veterans Affairs (VA), the National Institutes of Health, and private organizations. In 2013, STRONG STAR investigators partnered with the VA's National Center for PTSD and were selected for joint DoD/VA funding to establish the Consortium to Alleviate PTSD. STRONG STAR and the Consortium to Alleviate PTSD have assembled a critical mass of investigators and institutions with the synergy required to make major scientific and public health advances in the prevention and treatment of combat PTSD and related conditions. This manuscript provides an overview of the establishment of these two research consortia, including their history, vision, mission, goals, and accomplishments. Comprehensive tables provide descriptions of over 70 projects supported by the consortia. Examples are provided of collaborations among over 50 worldwide academic research institutions and over 150 investigators.

Pulmonary Arterial Pruning and Longitudinal Change in Percent Emphysema and Lung Function: The Genetic Epidemiology of COPD Study

BACKGROUND

Pulmonary endothelial damage has been shown to precede the development of emphysema in animals, and vascular changes in humans have been observed in COPD and emphysema.

RESEARCH QUESTION

Is intraparenchymal vascular pruning associated with longitudinal progression of emphysema on CT imaging or decline in lung function over 5 years?

STUDY DESIGN AND METHODS

The Genetic Epidemiology of COPD Study enrolled ever smokers with and without COPD from 2008 through 2011. The percentage of emphysema-like lung, or "percent emphysema," was assessed at baseline and after 5 years on noncontrast CT imaging as the percentage of lung voxels < -950 Hounsfield units. An automated CT imaging-based tool assessed and classified intrapulmonary arteries and veins. Spirometry measures are postbronchodilator. Pulmonary arterial pruning was defined as a lower ratio of small artery volume (< 5 mm2 cross-sectional area) to total lung artery volume. Mixed linear models included demographics, anthropomorphics, smoking, and COPD, with emphysema models also adjusting for CT imaging scanner and lung function models adjusting for clinical center and baseline percent emphysema.

RESULTS

At baseline, the 4,227 participants were 60 ± 9 years of age, 50% were women, 28% were Black, 47% were current smokers, and 41% had COPD. Median percent emphysema was 2.1 (interquartile range, 0.6-6.3) and progressed 0.24 percentage points/y (95% CI, 0.22-0.26 percentage points/y) over 5.6 years. Mean FEV1 to FVC ratio was 68.5 ± 14.2% and declined 0.26%/y (95% CI, -0.30 to -0.23%/y). Greater pulmonary arterial pruning was associated with more rapid progression of percent emphysema (0.11 percentage points/y per 1-SD increase in arterial pruning; 95% CI, 0.09-0.16 percentage points/y), including after adjusting for baseline percent emphysema and FEV1. Arterial pruning also was associated with a faster decline in FEV1 to FVC ratio (-0.04%/y per 1-SD increase in arterial pruning; 95% CI, -0.008 to -0.001%/y).

INTERPRETATION

Pulmonary arterial pruning was associated with faster progression of percent emphysema and more rapid decline in FEV1 to FVC ratio over 5 years in ever smokers, suggesting that pulmonary vascular differences may be relevant in disease progression.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.

Transcriptomic organization of the human brain in post-traumatic stress disorder

Despite extensive study of the neurobiological correlates of post-traumatic stress disorder (PTSD), little is known about its molecular determinants. Here, differential gene expression and network analyses of four prefrontal cortex subregions from postmortem tissue of people with PTSD demonstrate extensive remodeling of the transcriptomic landscape. A highly connected downregulated set of interneuron transcripts is present in the most significant gene network associated with PTSD. Integration of this dataset with genotype data from the largest PTSD genome-wide association study identified the interneuron synaptic gene ELFN1 as conferring significant genetic liability for PTSD. We also identified marked transcriptomic sexual dimorphism that could contribute to higher rates of PTSD in women. Comparison with a matched major depressive disorder cohort revealed significant divergence between the molecular profiles of individuals with PTSD and major depressive disorder despite their high comorbidity. Our analysis provides convergent systems-level evidence of genomic networks within the prefrontal cortex that contribute to the pathophysiology of PTSD in humans.

Utility of oxcarbazepine in the treatment of childhood and adolescent psychiatric symptoms

The primary aims of this study were to determine if oxcarbazepine is a safely tolerated option for treatment of psychiatric symptoms in children and whether its use facilitates dose modification of other psychotropic medications. A retrospective chart review was completed using data extracted from the electronic medical record of a large outpatient child psychiatry clinic. A total of 507 of 740 children prescribed oxcarbazepine for psychiatric indications for 3 months or more had adequate data to assess clinical responses and medication outcomes. Most patients prescribed oxcarbazepine experienced clinically significant control of irritability/anger, mood stabilization, aggressive outbursts, impulsivity, or anxiety, with over 80% achieving at least maintenance symptom control. In all, 51% and 25% fully discontinued second- or third-generation antipsychotic or antidepressant medication, respectively, after starting oxcarbazepine; 8% discontinued oxcarbazepine for nonresponse, while 9% stopped oxcarbazepine because of emergent side effects. In patients fully discontinuing or reducing the second- or third-generation antipsychotic dose by 50% or more, improvements in body mass index were observed. Oxcarbazepine may prove to be an appropriate alternative to antipsychotic and antidepressant medications for treating psychiatric symptoms in children and adolescents. In particular, it may be a more metabolically neutral psychotropic medication.

Psychiatric Prodrome in Anti-NMDAR-Associated Encephalopathy: Clinical and Pathophysiologic Considerations

OBJECTIVE

To present a review of the literature on the clinical presentation and pathophysiology of anti-N-methyl-d-aspartate receptor encephalopathy (ANMDARE) with attention to both the more commonly recognized psychotic symptom prodrome and the less well-understood depressive symptom prodrome.

DATA SOURCES

The search for clinical neuropsychiatric phenomena and proposed mechanisms involved in ANMDARE pathophysiology was conducted in PubMed. English-language articles published up to September 2019 were identified using a combination of the following search terms: N-methyl-d-aspartate, anti-NMDA receptor encephalitis, schizophrenia, psychosis, depression, major depressive disorder, bipolar I disorder, bipolar II disorder, anxiety, and posttraumatic stress disorder.

STUDY SELECTION

From 150 articles identified from the initial search, the 73 most relevant clinical studies, reviews, and case reports related to the study objectives were included.

DATA EXTRACTION

Sources were individually analyzed by the 3 authors for the most clinically relevant information.

RESULTS

The pathophysiology and mechanisms involved in anti-NMDA receptor antibody delivery to the brain are incompletely characterized, but antibody binding appears to involve the GluN1 subunit in most cases. Psychotic symptoms are the most commonly recognized components of prodromal psychiatric illness in ANMDARE, which may lead to an initial diagnosis of schizophrenia. In addition to psychotic symptoms, there are reports of depressive symptoms occurring before the emergence of, co-occurring with, or instead of psychotic symptoms in ANMDARE.

CONCLUSIONS

In addition to the better-known psychotic prodrome, depressive symptomatology can occur in ANMDARE patients. ANMDARE should be considered in patients with initial presentation of either psychotic or atypical depressive illnesses. Early recognition of these psychiatric prodromal states as antecedents to ANMDARE could lead to improved diagnosis and better management of this potentially life-threatening autoimmune disorder.

International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci

The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations.

Screening characteristics for enrichment of individuals at higher risk for transitioning to classified SLE

OBJECTIVE

Further prospective study is needed to elucidate the etiology and natural history of systemic lupus erythematosus development. The clinical complexity of this heterogeneous disease makes study design challenging. Our objective was to ascertain useful screening factors for identifying at-risk individuals for follow-up rheumatologic assessment or inclusion in prospective studies.

METHODS

We attempted to re-contact 3823 subjects with a family history of systemic lupus erythematosus, who did not meet American College of Rheumatology systemic lupus erythematosus classification at a baseline study visit; 436 agreed to follow-up participation an average of 6.3 years after baseline. In total, 56 of these individuals had transitioned to classified systemic lupus erythematosus (≥ 4 cumulative American College of Rheumatology criteria, verified by medical record review) by the time of follow up. Generalized estimating equations assessed associations between our dichotomous outcome of transitioning to systemic lupus erythematosus with baseline characteristics, including ANA positivity, Connective Tissue Disease Screening questionnaire systemic lupus erythematosus score, and number of American College of Rheumatology criteria. We analyzed predictive accuracy of characteristics on transitioning.

RESULTS

ANA positivity, Connective Tissue Disease Screening questionnaire systemic lupus erythematosus score categorization of possible or probable systemic lupus erythematosus, and greater number of American College of Rheumatology criteria at baseline were each associated with transitioning to systemic lupus erythematosus classification. Being ANA positive and having confirmed immunologic criteria at baseline had the highest positive predictive value and specificity for transitioning to systemic lupus erythematosus. American College of Rheumatology Connective Tissue Disease Screening questionnaire systemic lupus erythematosus score categorization of possible or probable systemic lupus erythematosus had a better positive predictive value, negative predictive value, sensitivity, and specificity than ANA positivity.

CONCLUSION

Given limited resources, identifying individuals for follow up based on the systemic lupus erythematosus portion of the Connective Tissue Disease Screening questionnaire could be an efficient way to identify family members at highest risk of disease transition.

Frontal Lobe Circuitry in Posttraumatic Stress Disorder

Symptoms of posttraumatic stress disorder include hyperarousal, avoidance of trauma-related stimuli, re-experiencing of trauma, and mood changes. This review focuses on the frontal cortical areas that form crucial links in circuitry pertinent to posttraumatic stress disorder symptomatology: (1) the conditioned fear extinction circuit, (2) the salience circuit, and (3) the mood circuit. These frontal areas include the ventromedial prefrontal cortex (conditioned fear extinction), the dorsal anterior cingulate and insular cortices (salience), and the lateral orbitofrontal and subgenual cingulate cortices (mood). Frontal lobe structural abnormalities in posttraumatic stress disorder, including volumetric reductions in the cingulate cortices, impact all three circuits. Functional analyses of frontal cortices in posttraumatic stress disorder show abnormal activation in all three according to task demand and emotional valence. Network analyses reveal altered amygdalo-frontal connectivity and failure to suppress the default mode network during cognitive engagement. Spine shape alterations also have been detected in the medial orbito-frontal cortex in posttraumatic stress disorder postmortem brains, suggesting reduced synaptic plasticity. Importantly, frontal lobe abnormalities in posttraumatic stress disorder extend beyond emotion-related circuits to include the lateral prefrontal cortices that mediate executive functions. In conclusion, widespread frontal lobe dysfunction in posttraumatic stress disorder provides a neurobiologic basis for the core symptomatology of the disorder, as well as for executive function impairment.

Genome-wide association study across European and African American ancestries identifies a SNP in DNMT3B contributing to nicotine dependence

Cigarette smoking is a leading cause of preventable mortality worldwide. Nicotine dependence, which reduces the likelihood of quitting smoking, is a heritable trait with firmly established associations with sequence variants in nicotine acetylcholine receptor genes and at other loci. To search for additional loci, we conducted a genome-wide association study (GWAS) meta-analysis of nicotine dependence, totaling 38,602 smokers (28,677 Europeans/European Americans and 9925 African Americans) across 15 studies. In this largest-ever GWAS meta-analysis for nicotine dependence and the largest-ever cross-ancestry GWAS meta-analysis for any smoking phenotype, we reconfirmed the well-known CHRNA5-CHRNA3-CHRNB4 genes and further yielded a novel association in the DNA methyltransferase gene DNMT3B. The intronic DNMT3B rs910083-C allele (frequency=44-77%) was associated with increased risk of nicotine dependence at P=3.7 × 10-8 (odds ratio (OR)=1.06 and 95% confidence interval (CI)=1.04-1.07 for severe vs mild dependence). The association was independently confirmed in the UK Biobank (N=48,931) using heavy vs never smoking as a proxy phenotype (P=3.6 × 10-4, OR=1.05, and 95% CI=1.02-1.08). Rs910083-C is also associated with increased risk of squamous cell lung carcinoma in the International Lung Cancer Consortium (N=60,586, meta-analysis P=0.0095, OR=1.05, and 95% CI=1.01-1.09). Moreover, rs910083-C was implicated as a cis-methylation quantitative trait locus (QTL) variant associated with higher DNMT3B methylation in fetal brain (N=166, P=2.3 × 10-26) and a cis-expression QTL variant associated with higher DNMT3B expression in adult cerebellum from the Genotype-Tissue Expression project (N=103, P=3.0 × 10-6) and the independent Brain eQTL Almanac (N=134, P=0.028). This novel DNMT3B cis-acting QTL variant highlights the importance of genetically influenced regulation in brain on the risks of nicotine dependence, heavy smoking and consequent lung cancer.

Less than 7 hours of sleep per night is associated with transitioning to systemic lupus erythematosus

Background The role of sleep in the etiology of systemic lupus erythematosus (SLE) has not been well studied. We examined whether sleep duration was associated with subsequent transitioning to SLE in individuals at risk for SLE. Methods Four hundred and thirty-six relatives of SLE patients who did not have SLE themselves at baseline were evaluated again an average of 6.3 (± 3.9) years later. Fifty-six individuals transitioned to SLE (≥ 4 cumulative American College of Rheumatology (ACR) criteria). Sleep duration, medication use and medical history were assessed by questionnaire; ACR criteria were confirmed by medical record review. Vitamin D was measured by ELISA. Generalized estimating equations, accounting for correlation within families, assessed associations between baseline sleep and the outcome of transitioning to SLE. Results Reporting sleeping less than 7 hours per night at baseline was more common in those who subsequently transitioned than those who did not transition to SLE (55% versus 32%, p = 0.0005; OR: 2.8, 95% CI 1.6-4.9). Those who transitioned to SLE were more likely to sleep less than 7 hours per night than those who did not transition to SLE adjusting for age, sex and race (OR: 2.8, 95% CI 1.6-5.1). This association remained after individual adjustment for conditions and early symptoms that could affect sleep, including prednisone use, vitamin D deficiency and number of ACR criteria (OR: 2.0, 95% CI 1.1-4.2). Conclusion Lack of sleep may be associated with transitioning to SLE, independent of early clinical manifestations of SLE that may influence sleep duration. Further evaluation of sleeping patterns and biomarkers in at-risk individuals is warranted.

BA11 FKBP5 expression levels correlate with dendritic spine density in postmortem PTSD and controls

Genetic variants of the immunophilin FKBP5 have been implicated in susceptibility to post-traumatic stress disorder (PTSD) and other stress-related disorders. We examined the relationship between mushroom, stubby, thin and filopodial spine densities measured with Golgi staining and FKBP5 gene expression in the medial orbitofrontal cortex (BA11) in individuals diagnosed with PTSD and normal controls (n = 8/8). ANCOVA revealed PTSD cases had a significantly elevated density of stubby spines (29%, P < 0.037) and a trend for a reduction in mushroom spine density (25%, p < 0.082). Levels of FKBP5 mRNA were marginally elevated in the PTSD cases (z = 1.94, p = 0.053) and levels correlated inversely with mushroom (Spearman's rho = −0.83, p < 0.001) and overall spine density (rho = −0.75, p < 0.002) and directly with stubby spine density (rho = 0.55, p < 0.027). These data suggest that FKBP5 may participate in a cellular pathway modulating neuronal spine density changes in the brain, and that this pathway may be dysregulated in PTSD.

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The present study is one of the first human post-mortem PTSD studies to date.

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Extreme stress has robust repercussions on glucocorticoids and dendritic spine morphology in animal models.

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FKBP5, involved in glucocorticoid signaling, was inversely associated with mushroom spine density in frontal cortex.

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These findings are consistent with alterations in glucocorticoid signaling in PTSD affecting synaptic plasticity.

An examination of the broader effects of warzone experiences on returning Iraq/Afghanistan veterans' psychiatric health

The objective of the present research was to test the hypotheses that: (1) Iraq/Afghanistan war veterans experience a wide range of psychiatric symptomatology (e.g., obsessive-compulsive symptoms, hypochondriasis, somatization); and (2) general psychiatric symptomatology among Iraq/Afghanistan war veterans is associated with their warzone experiences. To achieve this objective, Iraq/Afghanistan war veterans (N=155) completed a screening questionnaire that assessed a wide range of psychiatric symptoms along with a measure of warzone experiences. As expected, returning veterans reported significant elevations across a wide range of clinical scales. Approximately three-fourths screened positive on at least one clinical subscale, and a one-third screened positive on five or more. In addition, nearly all of these conditions were associated with veterans' warzone experiences (average r=0.36); however, this association was much stronger among veterans with posttraumatic stress disorder (PTSD) (average r=0.33) than among veterans without PTSD (average r=0.15). We also observed that approximately 18% of the variance in total psychiatric symptomatology was attributable to warzone experiences above and beyond the effects of childhood trauma and demographic factors. Taken together, these findings suggest that returning veterans experience a broad array of psychiatric symptoms that are strongly associated with their warzone experiences.

Do child abuse and maternal care interact to predict military sexual trauma?

OBJECTIVE

The present research tested the hypothesis that maternal care moderates the relationship between childhood sexual abuse and subsequent military sexual trauma (MST).

METHOD

Measures of childhood sexual abuse, maternal care, and MST were administered to 197 Iraq and Afghanistan war veterans.

RESULTS

After accounting for gender, age, and the main effects of maternal care and childhood sexual abuse, the maternal care x childhood sexual abuse interaction was a significant predictor of MST (odds ratio = .28, β = -1.26, 95% confidence intervals of .10, .80). As hypothesized, rates of MST were higher among veterans who reported childhood sexual abuse and low levels of maternal care (43%) compared with veterans who reported childhood sexual abuse and high levels of maternal care (11%).

CONCLUSION

These findings suggest that high levels of maternal care may act as a protective factor against future revictimization among military service members. These findings have the potential to inform both prevention and intervention efforts.

Effect of the 5-HTTLPR polymorphism on posttraumatic stress disorder, depression, anxiety, and quality of life among Iraq and Afghanistan veterans

BACKGROUND AND OBJECTIVES

Posttraumatic stress disorder (PTSD), depression, anxiety, and stress are significant problems among returning veterans and are associated with reduced quality of life.

DESIGN

A correlational design was used to examine the impact of a polymorphism (5-HTTLPR) in the serotonin transporter promoter gene on post-deployment adjustment among returning veterans.

METHODS

A total of 186 returning Iraq and Afghanistan veterans were genotyped for the 5-HTTLPR polymorphism. Symptoms of PTSD, depression, general stress, and anxiety were assessed along with quality of life.

RESULTS

After controlling for combat exposure, age, sex of the participant, and race, 5-HTTLPR had a significant multivariate effect on post-deployment adjustment, such that S' carriers reported more post-deployment adjustment problems and worse quality of life than veterans homozygous for the L' allele. This effect was larger when the analyses were restricted to veterans of European ancestry.

CONCLUSIONS

Our findings suggest that veterans who carry the S' allele of the 5-HTTLPR polymorphism may be at increased risk for adjustment problems and reduced quality of life following deployments to war zones.

Smoking is not associated with autoantibody production in systemic lupus erythematosus patients, unaffected first-degree relatives, nor healthy controls

OBJECTIVE

The objective of this paper is to examine whether smoking is associated with autoantibody production in systemic lupus erythematosus (SLE) patients, unaffected first-degree relatives (FDR) of individuals with SLE--a group at increased risk of developing SLE--or unaffected, unrelated controls.

METHODS

Detailed demographic, environmental, clinical, and therapeutic information was collected by questionnaire on 1242 SLE patients, 981 FDRs, and 946 controls in the Lupus Family Registry and Repository; a blood sample was obtained. All sera were tested for multiple lupus autoantibodies by immunofluorescence and luminex bead-based assays. Generalized estimating equations, adjusting for age, gender, and ethnicity and accounting for correlation within families, were used to assess smoking status with the dichotomous outcome variables of positivity for SLE status, positivity of ANA by immunofluorescence (≥1:120), positivity for ≥1 autoantibody by the luminex assay, and positivity for each of the 11 autoantibodies.

RESULTS

Current smoking was associated with being positive for ≥1 autoantibody (excluding ANA) (adjusted OR = 1.53, 95% CI 1.04-2.24) in our subjects with SLE. No association was observed in unaffected FDRs or healthy controls. Former smoking was associated with anti-Ro/SS-A60 in our unaffected FDRs. There was an increased association with anti-nRNP A seropositivity, as well as a decreased association with anti-nRNP 68 positivity, in current smokers in SLE subjects.

CONCLUSIONS

No clear association between smoking status and individual autoantibodies was detected in SLE patients, unaffected FDRs, nor healthy controls within this collection. The association of smoking with SLE may therefore manifest its risk through mechanisms outside of autoantibody production, at least for the specificities tested.

Depletion of serotonin in the basolateral amygdala elevates glutamate receptors and facilitates fear-potentiated startle

Our previous experiments demonstrated that systemic depletion of serotonin (5-hydroxytryptamine, 5-HT), similar to levels reported in patients with emotional disorders, enhanced glutamateric activity in the lateral nucleus of the amygdala (LA) and potentiated fear behaviors. However, the effects of isolated depletion of 5-HT in the LA, and the molecular mechanisms underlying enhanced glutamatergic activity are unknown. In the present study, we tested the hypothesis that depletion of 5-HT in the LA induces increased fear behavior, and concomitantly enhances glutamate receptor (GluR) expression. Bilateral infusions of 5,7-dihydroxytryptamine (4 μg per side) into the LA produced a regional reduction of serotonergic fibers, resulting in decreased 5-HT concentrations. The induction of low 5-HT in the LA elevated fear-potentiated startle, with a parallel increase in GluR1 mRNA and GluR1 protein expression. These findings suggest that low 5-HT concentrations in the LA may facilitate fear behavior through enhanced GluR-mediated mechanisms. Moreover, our data support a relationship between 5-HT and glutamate in psychopathologies.

Neuropsychological sequelae of PTSD and TBI following war deployment among OEF/OIF veterans

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are highly prevalent among Veterans of the conflicts in Iraq and Afghanistan. These conditions are associated with common and unique neuropsychological and neuroanatomical changes. This review synthesizes neuropsychological and neuroimaging studies for both of these disorders and studies examining their co-occurrence. Recommendations for future research, including use of combined neuropsychological and advanced neuroimaging techniques to study these disorders alone and in concert, are presented. It is clear from the dearth of literature that addiitonal studies are required to examine and understand the impact of specific factors on neurocognitive outcome. Of particular relevance are temporal relationships between PTSD and mTBI, risk and resilience factors associated with both disorders and their co-occurrence, and mTBI-specific factors such as time since injury and severity of injury, utilizing comprehensive, yet targeted cognitive tasks.

The functional connectivity of the human caudate: an application of meta-analytic connectivity modeling with behavioral filtering

Meta-analysis based techniques are emerging as powerful, robust tools for developing models of connectivity in functional neuroimaging. Here, we apply meta-analytic connectivity modeling to the human caudate to 1) develop a model of functional connectivity, 2) determine if meta-analytic methods are sufficiently sensitive to detect behavioral domain specificity within region-specific functional connectivity networks, and 3) compare meta-analytic driven segmentation to structural connectivity parcellation using diffusion tensor imaging. Results demonstrate strong coherence between meta-analytic and data-driven methods. Specifically, we found that behavioral filtering resulted in cognition and emotion related structures and networks primarily localized to the head of the caudate nucleus, while perceptual and action specific regions localized to the body of the caudate, consistent with early models of nonhuman primate histological studies and postmortem studies in humans. Diffusion tensor imaging (DTI) revealed support for meta-analytic connectivity modeling's (MACM) utility in identifying both direct and indirect connectivity. Our results provide further validation of meta-analytic connectivity modeling, while also highlighting an additional potential, namely the extraction of behavioral domain specific functional connectivity.

High psychopathic trait females exhibit reduced startle potentiation and increased p3 amplitude

While there has been steady progress in identifying psychophysiological traits associated with psychopathy, most of the existing research has been carried out using incarcerated male participants, and data that include females are particularly rare. This study examined both affective startle blink modulation and P3 amplitude in a sample of female undergraduates grouped by scores on the Psychopathic Personality Inventory-Revised (PPI-R). Those scoring high for psychopathic traits lacked startle blink potentiation and demonstrated larger P3 amplitudes during auditory and visual oddball tasks. These data support the generalizability of deficient startle potentiation to non-incarcerated females with psychopathic traits, and add to a growing body of literature suggesting that psychopathic traits are associated with distinctive information-processing characteristics as indexed by P3 amplitude.

PSAPP mice exhibit regionally selective reductions in gliosis and plaque deposition in response to S100B ablation

BACKGROUND

Numerous studies have reported that increased expression of S100B, an intracellular Ca2+ receptor protein and secreted neuropeptide, exacerbates Alzheimer's disease (AD) pathology. However, the ability of S100B inhibitors to prevent/reverse AD histopathology remains controversial. This study examines the effect of S100B ablation on in vivo plaque load, gliosis and dystrophic neurons.

METHODS

Because S100B-specific inhibitors are not available, genetic ablation was used to inhibit S100B function in the PSAPP AD mouse model. The PSAPP/S100B-/- line was generated by crossing PSAPP double transgenic males with S100B-/- females and maintained as PSAPP/S100B+/- crosses. Congo red staining was used to quantify plaque load, plaque number and plaque size in 6 month old PSAPP and PSAPP/S100B-/- littermates. The microglial marker Iba1 and astrocytic marker glial fibrillary acidic protein (GFAP) were used to quantify gliosis. Dystrophic neurons were detected with the phospho-tau antibody AT8. S100B immunohistochemistry was used to assess the spatial distribution of S100B in the PSAPP line.

RESULTS

PSAPP/S100B-/- mice exhibited a regionally selective decrease in cortical but not hippocampal plaque load when compared to PSAPP littermates. This regionally selective reduction in plaque load was accompanied by decreases in plaque number, GFAP-positive astrocytes, Iba1-positive microglia and phospho-tau positive dystrophic neurons. These effects were not attributable to regional variability in the distribution of S100B. Hippocampal and cortical S100B immunoreactivity in PSAPP mice was associated with plaques and co-localized with astrocytes and microglia.

CONCLUSIONS

Collectively, these data support S100B inhibition as a novel strategy for reducing cortical plaque load, gliosis and neuronal dysfunction in AD and suggest that both extracellular as well as intracellular S100B contribute to AD histopathology.

Oxytocin and vasopressin immunoreactive staining in the brains of Brandt's voles (Lasiopodomys brandtii) and greater long-tailed hamsters (Tscherskia triton)

Immunoreactive (ir) staining of the neuropeptides oxytocin (OT) and vasopressin (AVP) was performed in the brains of Brandt's voles (Lasiopodomys brandtii) and greater long-tailed hamsters (Tscherskia triton)-two species that differ remarkably in social behaviors. Social Brandt's voles had higher densities of OT-ir cells in the medial preoptic area (MPOA) and medial amygdala (MeA) as well as higher densities of AVP-ir cells in the lateral hypothalamus (LH) compared to solitary greater long-tailed hamsters. In contrast, the hamsters had higher densities of OT-ir cells in the anterior hypothalamus (AH) and LH and higher densities of AVP-ir cells in the MPOA than the voles. OT-ir and AVP-ir fibers were also found in many forebrain areas with subtle species differences. Given the roles of OT and AVP in the regulation of social behaviors in other rodent species, our data support the hypothesis that species-specific patterns of central OT and AVP pathways may underlie species differences in social behaviors. However, despite a higher density of OT-ir cells in the paraventricular nucleus of the hypothalamus (PVN) in females than in males in both species, no other sex differences were found in OT-ir or AVP-ir staining. These data failed to support our prediction that a sexually dimorphic pattern of neuropeptide staining in the brain is more apparent in Brandt's voles than in greater long-tailed hamsters.

Centella asiatica extract selectively decreases amyloid beta levels in hippocampus of Alzheimer's disease animal model

PSAPP mice expressing the 'Swedish' amyloid precursor protein and the M146L presenilin 1 mutations are a well-characterized model for spontaneous amyloid beta plaque formation. Centella asiatica has a long history of use in India as a memory enhancing drug in Ayurvedic literature. The study investigated whether Centella asiatica extract (CaE) can alter the amyloid pathology in PSAPP mice by administering CaE (2.5 or 5.0 g/kg/day) starting at 2 months of age prior to the onset of detectable amyloid deposition and continued for either 2 months or 8 months. A significant decrease in amyloid beta 1-40 and 1-42 was detectable by ELISA following an 8 month treatment with 2.5 mg/kg of CaE. A reduction in Congo Red stained fibrillar amyloid plaques was detected with the 5.0 mg/kg CaE dose and long-term treatment regimen. It was also confirmed that CaE functions as an antioxidant in vitro, scavenging free radicals, reducing lipid peroxidation and protecting against DNA damage. The data indicate that CaE can impact the amyloid cascade altering amyloid beta pathology in the brains of PSAPP mice and modulating components of the oxidative stress response that has been implicated in the neurodegenerative changes that occur with Alzheimer's disease.

An animal model of hypnotic pain attenuation

The tonic immobility state (TIS) in rabbit has great potential as an animal model of hypnosis in humans, due to the strong similarities between TIS and hypnosis. It is additionally the only mammalian model available for studying mechanisms of hypnosis. However, its ability to modulate pain perception has yet to be clearly determined. The present experiment examined the effect of nociceptive conditioning in normal, TIS and lidocaine-treated rabbits. This involved three separate phases. In phase one all animals were trained on a continuous performance test (CPT). In the second phase animals were given Pavlovian conditioning to an auditory CS paired with a nociceptive US. In the third phase the animals are given a sensory recognition test. The control group were conditioned during a normal state, the TIS group were conditioned during TIS, the pain control animals were conditioned after lidocaine injection in the skin area stimulated by the nociceptive US. All animals in the normal group showed the greatest amount of pain conditioning, with an average disruption time (dt) of 175s. Animals in the lidocaine group showed little signs of conditioning with an average dt of 16s. Animals conditioned during TIS had an average dt of 42s. These results show that TIS can modulate pain perception similar to animals that did not experience a pain CS. They additionally argue that tonic immobility can produce attenuation of pain perception similar to hypnosis in humans.

Major depression, 5HTTLPR genotype, suicide and antidepressant influences on thalamic volume

BACKGROUND

The 5HTTLPR genetic variant of the serotonin transporter gene (SERT or 5-HTT), which is comprised of a short (SERT-s) and a long (SERT-l) allele, is associated with major depressive disorder and post-traumatic brain disorder.

AIMS

The present study sought to determine whether the total thalamus and major subregions are altered in size in major depressive disorder and in relation to the 5HTTLPR genotype.

METHOD

We investigated the influence of 5HTTLPR genotype, psychiatric diagnosis, suicide and other clinical factors on the volume of the entire post-mortem thalamus.

RESULTS

Major depressive disorder, SERT-ss genotype and suicide emerged as independent factors contributing to an enlargement of the total thalamus. The majority of the volume enlargement associated with the SERT-ss genotype occurred in the pulvinar, whereas enlargement associated with major depressive disorder occurred in the limbic nuclei and in other regions of the thalamus. A history of antidepressant treatment was associated with reduced thalamic volume.

CONCLUSIONS

The 5HTTLPR genetic variation may affect behaviour and psychiatric conditions, in part, by altering the anatomy of the thalamus.

Neuroprotective mechanisms of ayurvedic antidementia botanical Bacopa monniera

Alzheimer's disease is a neurodegenerative disorder characterized by progressive dementia. Bacopa monniera is described in the Ayurvedic Materia Medica, as a therapeutically useful herb for the treatment of cognitive impairment, thus supporting its possible anti-Alzheimer's properties. Our studies have shown that Bacopa monniera reduces beta-amyloid deposits in the brain of an Alzheimer's disease animal model. The objective of this study was to establish the presence of endogenous substances in Bacopa monniera extract (BmE) that will impact components of the oxidative stress cascade such as the reduction of divalent metals, scavenging of reactive oxygen species, alterations of lipoxygenase activity and hydrogen peroxide-induced lipid peroxidation. The extract contained polyphenols and sulfhydryl contents suggestive of endogenous antioxidant activity. The results demonstrated that BmE reduced divalent metals, dose-dependently scavenged reactive oxygen species, decreased the formation of lipid peroxides and inhibited lipoxygenase activity. These data combined with our previous studies that have shown that BmE treatment reduces beta-amyloid levels in the brain of an Alzheimer's disease doubly transgenic mouse model of rapid amyloid deposition (PSAPP mice) suggesting mechanisms of action relevant to the treatment of Alzheimer's disease.

Neonatal lung side population cells demonstrate endothelial potential and are altered in response to hyperoxia-induced lung simplification

Lung side population (SP) cells are resident lung precursor cells with both epithelial and mesenchymal potential that are believed to play a role in normal lung development and repair. Neonatal hyperoxic exposure impairs lung development leading to a long-term decrease in gas exchange surfaces. The hypothesis that lung SP cells are altered during impaired lung development has not been studied. To address this issue, we characterized the endothelial potential of neonatal lung SP and subsets of lung SP from neonatal mice following hyperoxic exposure during room air recovery. Lung SP cells were isolated and sorted on the basis of their capacity to efflux Hoechst 33342. The lung SP was further sorted based on expression of Flk-1 and CD45. In vitro, both CD45pos/Flk-1pos and CD45neg/Flk-1pos bind isolectin B4 and incorporate LDL and form networks in matrigel, indicating that these populations have endothelial cell characteristics. Hyperoxic exposure of neonatal mice resulted in subtle changes in vascular and alveolar density on P13, which persisted with room air recovery to P41. During room air recovery, a decrease in lung SP cells was detected in the hyperoxic-exposed group on postnatal day 13 followed by an increase on day 41. Within this group, the lung SP subpopulation of cells expressing CD45 increased on day 21, 41, and 55. Here, we show that lung SP cells demonstrate endothelial potential and that the population distribution changes in number as well as composition following hyperoxic exposure. The hyperoxia-induced changes in lung SP cells may limit their ability to effectively contribute to tissue morphogenesis during room air recovery.

5HTTLPR polymorphism and enlargement of the pulvinar: unlocking the backdoor to the limbic system

BACKGROUND

The 5HTTLPR genetic variant of the serotonin transporter (SERT), which consists of a long (SERT-l) and short (SERT-s) allele, has emerged as a major factor influencing emotional behavior and brain anatomy. The pulvinar nucleus of the thalamus projects to important limbic nuclei including the amygdala and cingulate cortex, is involved in the processing of stimuli with emotional content, and contains an abundance of SERT.

METHODS

Stereological methods were used to measure pulvinar neuron number in postmortem tissue from major depressive disorder (n = 11), bipolar disorder (n = 11), schizophrenia (n = 12), and control (n = 15) specimens from the Stanley Foundation Neuropathology Consortium. The effect of SERT genotype on pulvinar volume and neuron number was investigated by using analysis of covariance.

RESULTS

Analysis of covariance with diagnosis, SERT genotype, age, hemisphere, postmortem interval, and time-in-formalin covariates identified a 20% increase in pulvinar neuron number and volume in SERT-ss subjects.

CONCLUSIONS

The elevated number of pulvinar neurons in subjects with a SERT-ss genotype may serve to enhance subcortical input of emotionally relevant stimuli to the limbic system, providing a mechanism for the 5HTTLPR genetic variant to affect predisposition to conditions such as major depression.

Bacopa monniera extract reduces amyloid levels in PSAPP mice

PSAPP mice expressing the "Swedish" amyloid precursor protein and M146L presenilin-1 mutations are a well-characterized model for spontaneous amyloid plaque formation. Bacopa monniera has a long history of use in India as an anti-aging and memory-enhancing ethnobotanical therapy. To evaluate the effect of Bacopa monniera extract (BME) on amyloid (Abeta) pathology in PSAPP mice, two doses of BME (40 or 160 mg/kg/day) were administered starting at 2 months of age for either 2 or 8 months. Our present data suggests that BME lowers Abeta 1-40 and 1-42 levels in cortex by as much as 60%, and reverses Y-maze performance and open field hyperlocomotion behavioral changes present in PSAPP mice. The areas encompassed by Congo Red-positive fibrillar amyloid deposits, however, were not altered by BME treatment. The data suggest that BME has potential application in Alzheimer's disease therapeutics.

Galantamine improves cognition in schizophrenic patients stabilized on risperidone

BACKGROUND

Cognition in schizophrenia is impaired in a variety of cognitive domains. Galantamine, a cholinesterase inhibitor with putative nicotinic agonist-like effects, improves cognition in Alzheimer's patients.

METHODS

Sixteen schizophrenic or schizoaffective patients stabilized on risperidone were administered galantamine (n=8) or placebo (n=8) in a randomized, double-blind trial. The Repeatable Battery for Assessment of Neuropsychological Status (RBANS) assessed changes in cognitive performance over an eight-week treatment interval.

RESULTS

Clinical symptoms improved in both groups during the trial with no evidence that galantamine exacerbated extrapyramidal symptoms. Patients treated with galantamine experienced an overall improvement in cognitive performance (RBANS Total scale score; galantamine = 12.1 +/- 12.8 SD, placebo = .5 +/- 13.5, t = 2.32, p < .04). Confidence intervals suggest that RBANS Attention and Delayed Memory subscale performance was robustly improved in galantamine patients by approximately one standard deviation, effectively normalizing cognitive performance in these domains.

CONCLUSIONS

Adjunctive treatment with galantamine improves memory and attention in patients with schizophrenia who are stabilized on risperidone, providing the opportunity to improve functional outcome in these patients.

Mice deficient in galectin-1 exhibit attenuated physiological responses to chronic hypoxia-induced pulmonary hypertension

Pulmonary hypertension (PH) is characterized by sustained vasoconstriction, with subsequent extracellular matrix (ECM) production and smooth muscle cell (SMC) proliferation. Changes in the ECM can modulate vasoreactivity and SMC contraction. Galectin-1 (Gal-1) is a hypoxia-inducible beta-galactoside-binding lectin produced by vascular, interstitial, epithelial, and immune cells. Gal-1 regulates SMC differentiation, proliferation, and apoptosis via interactions with the ECM, as well as immune system function, and, therefore, likely plays a role in the pathogenesis of PH. We investigated the effects of Gal-1 during hypoxic PH by quantifying 1) Gal-1 expression in response to hypoxia in vitro and in vivo and 2) the effect of Gal-1 gene deletion on the magnitude of the PH response to chronic hypoxia in vivo. By constructing and screening a subtractive library, we found that acute hypoxia increases expression of Gal-1 mRNA in isolated pulmonary mesenchymal cells. In wild-type (WT) mice, Gal-1 immunoreactivity increased after 6 wk of hypoxia. Increased expression of Gal-1 protein was confirmed by quantitative Western analysis. Gal-1 knockout (Gal-1(-/-)) mice showed a decreased PH response, as measured by right ventricular pressure and the ratio of right ventricular to left ventricular + septum wet weight compared with their WT counterparts. However, the number and degree of muscularized vessels increased similarly in WT and Gal-1(-/-) mice. In response to chronic hypoxia, the decrease in factor 8-positive microvessel density was similar in both groups. Vasoreactivity of WT and Gal-1(-/-) mice was tested in vivo and with use of isolated perfused lungs exposed to acute hypoxia. Acute hypoxia caused a significant increase in RV pressure in wild-type and Gal-1(-/-) mice; however, the response of the Gal-1(-/-) mice was greater. These results suggest that Gal-1 influences the contractile response to hypoxia and subsequent remodeling during hypoxia-induced PH, which influences disease progression.

An empirical approach for delayed oscillator stability and parametric identification

This paper investigates a semi-empirical approach for determining the stability of systems that can be modelled by ordinary differential equations with a time delay. This type of model is relevant to biological oscillators, machining processes, feedback control systems and models for wave propagation and reflection, where the motion of the waves themselves is considered to be outside the system model. A primary aim is to investigate the extension of empirical Floquet theory to experimental or numerical data obtained from time-delayed oscillators. More specifically, the reconstructed time series from a numerical example and an experimental milling system are examined to obtain a finite number of characteristic multipliers from the reduced order dynamics. A secondary goal of this work is to demonstrate a benefit of empirical characteristic multiplier estimation by performing system identification on a delayed oscillator. The principal results from this study are the accurate estimation of delayed oscillator characteristic multipliers and the utilization the empirical results for parametric identification of model parameters. Combining these results with previous research on an experimental milling system provides a particularly relevant result—the first approach for identifying all model parameters for stability prediction directly from the cutting process vibration history.

Genome scan of schizophrenia families in a large Veterans Affairs Cooperative Study sample: evidence for linkage to 18p11.32 and for racial heterogeneity on chromosomes 6 and 14

Genome-wide linkage analyses of schizophrenia have identified several regions that may harbor schizophrenia susceptibility genes but, given the complex etiology of the disorder, it is unlikely that all susceptibility regions have been detected. We report results from a genome scan of 166 schizophrenia families collected through the Department of Veterans Affairs Cooperative Studies Program. Our definition of affection status included schizophrenia and schizoaffective disorder, depressed type and we defined families as European American (EA) and African American (AA) based on the probands' and parents' races based on data collected by interviewing the probands. We also assessed evidence for racial heterogeneity in the regions most suggestive of linkage. The maximum LOD score across the genome was 2.96 for chromosome 18, at 0.5 cM in the combined race sample. Both racial groups showed LOD scores greater than 1.0 for chromosome 18. The empirical P-value associated with that LOD score is 0.04 assuming a single genome scan for the combined sample with race narrowly defined, and 0.06 for the combined sample allowing for broad and narrow definitions of race. The empirical P-value of observing a LOD score as large as 2.96 in the combined sample, and of at least 1.0 in each racial group, allowing for narrow and broad racial definitions, is 0.04. Evidence for the second and third largest linkage signals come solely from the AA sample on chromosomes 6 (LOD = 2.11 at 33.2 cM) and 14 (LOD = 2.13 at 51.0). The linkage evidence differed between the AA and EA samples (chromosome 6 P-value = 0.007 and chromosome 14 P-value = 0.004).

Clozapine and the mitogen-activated protein kinase signal transduction pathway: implications for antipsychotic actions

BACKGROUND

Mitogen-activated protein kinase (MAPK) signaling pathways respond to dopaminergic and serotonergic agents and mediate short- and long-term effects of intracellular signaling in neurons. Here we show that the antipsychotic agent, clozapine, selectively activates the MEK/ERK MAPK pathway, and inhibition of this pathway reverses clozapine's actions in the conditioned avoidance response (CAR) paradigm, a rodent behavioral assay of antipsychotic activity.

METHODS

Phosphorylation patterns of MAPK pathway enzymes were determined by quantitative immunoblot analysis and immunohistochemistry of rat prefrontal cortex. Kinase inhibitors were used to assess the role of MAPK signaling pathways in mediating clozapine-induced suppression of CAR.

RESULTS

Clozapine administration selectively increased phosphorylation of MEK1/2 but had no effect on p38 or JNK phosphorylation. Pretreatment with the 5-HT2A agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride blocked the clozapine-induced increase in MEK1/2 phosphorylation. Immunohistochemistry revealed that clozapine treatment elevated the number of cells in the prefrontal cortex positive for phosphoERK, the downstream substrate of MEK1/2. Prior administration of MEK1/2 inhibitors U0126 or Sl327, or ERK inhibitor 5-iodotubercidin, reversed suppression of CAR induced by clozapine, whereas administration of vehicle, JNK or p38 inhibitors (L-JNK-1 and SB203580, respectively) had no effect. Inhibition of kinases upstream to MEK1/2 (PI-3K, PKC, and CaMKII) by administration of LY294002, bisindolylmaleimide, or KN-62, respectively, also reversed clozapine-induced suppression of CAR.

CONCLUSIONS

These data support the hypothesis that the MEK/ERK signal transduction cascade participates in clozapine's antipsychotic actions.

Elevated prevalence of hepatitis C infection in users of United States veterans medical centers

Several studies suggest veterans have a higher prevalence of hepatitis C virus infection than nonveterans, possibly because of military exposures. The purpose of this study was to estimate the prevalence of anti-hepatitis C antibody and evaluate factors associated with infection among users of Department of Veterans Affairs medical centers. Using a two-staged cluster sample, 1288 of 3863 randomly selected veterans completed a survey and underwent home-based phlebotomy for serological testing. Administrative and clinical data were used to correct the prevalence estimate for nonparticipation. The prevalence of antihepatitis C antibody among serology participants was 4.0% (95% CI, 2.6%-5.5%). The estimated prevalence in the population of Veterans Affairs medical center users was 5.4% (95% CI, 3.3%-7.5%) after correction for sociodemographic and clinical differences between participants and nonparticipants. Significant predictors of seropositivity included demographic factors, period of military service (e.g., Vietnam era), prior diagnoses, health care use, and lifestyle factors. At least one traditional risk factor (transfusion or intravenous drug use) was reported by 30.2% of all subjects. Among those testing positive for hepatitis C antibody, 78% either had a transfusion or had used injection drugs. Adjusting for injection drug use and nonparticipation, seropositivity was associated with tattoos and incarceration. Military-related exposures were not found to be associated with infection in the adjusted analysis. In conclusion, the prevalence of hepatitis C in these subjects exceeds the estimate from the general US population by more than 2-fold, likely reflecting more exposure to traditional risk factors among these veterans.

Elevated neuron number in the limbic thalamus in major depression

OBJECTIVE

The mediodorsal and anteroventral/anteromedial nuclei of the thalamus are brain regions of interest in the study of mood disorders because they connect subcortical limbic system structures such as the amygdala with the prefrontal, cingulate, and temporal cortices. Anatomical abnormalities have been observed both in the amygdala and in the aforementioned cortical regions in affective disorder patients. Neuroanatomical studies of the thalamus have rarely been conducted in patients with mood disorders.

METHOD

Postmortem tissue from the Stanley Foundation Brain Bank was obtained from subjects diagnosed with major depressive disorder, bipolar disorder, and schizophrenia as well as a nonpsychiatric comparison group (N=10-13 per group). The optical disector stereological procedure was used to count neurons in the mediodorsal and anteroventral/anteromedial nuclei of the thalamus in each brain.

RESULTS

There were significantly more neurons in the mediodorsal (37%) and anteroventral/anteromedial (26%) nuclei in subjects with major depressive disorder relative to the nonpsychiatric comparison subjects. Neuron numbers and volumes in these limbic thalamic nuclei were normal in the schizophrenia and bipolar subjects.

CONCLUSIONS

The data indicate that there is an elevation in total neuron number in the limbic thalamus that is specific for major depressive disorder. This represents the first report of a neuropsychiatric disorder being associated with an increase in total regional neuron number. The present findings, along with recent data, indicate that significant anatomical and functional abnormalities are present in limbic circuits in major depressive disorder.

Evaluation of low-phytate corn and barley on broiler chick performance

Grains produced by low-phytate barley and corn isolines homozygous for each species' respective low phytic acid 1-1 allele were compared to grain produced by near-isogenic normal or wild-type barley and corn in broiler chick feeds. Cobb x Cobb (384) chicks were used in a 10-d study. A randomized complete block design with a factorial arrangement of 2 x 2 x 3 was used with 4 replicates (8 chicks / replicate) per treatment. Twelve isocaloric and isonitrogenous treatment diets were formulated to contain 2 types of grain (barley and corn), 2 levels of grain (40% and 60%), and 3 sources of available P (wild-type grain, wild-type P-supplemented grain, and low-phytate grain). Growth parameters, bone parameters, total bone mineral, and apparent digestibilities were measured. The mean growth and bone responses were 1) higher for barley diets compared to corn diets, 2) higher for 60% grain inclusion compared to 40%, 3) higher for low-phytate compared to wild-type grains, and 4) not different for low-phytate compared to P-supplemented wild-type grain diets. Chicks fed low-phytate-based diets excreted 33 and 43% less P than chicks fed wild-type and P-supplemented wild-type diets, respectively. Correlations between percentage bone ash, total bone ash, and bone strength indicated a strong relationship and appear to support the use of bone strength analysis as a simpler method than ash content determination as an indication of P status. Feeding low-phytate grains will reduce the need for supplemental P in chick diets.

Modest evidence for linkage and possible confirmation of association between NOTCH4 and schizophrenia in a large Veterans Affairs Cooperative Study sample

Wei and Hemmings [2000: Nat Genet 25:376-377], using 80 British parent-offspring trios, identified a number of NOTCH4 variants and haplotypes that showed statistically significant evidence of association to schizophrenia. Specifically, the 10 repeat allele of a (CTG)(n) marker and the 8 repeat allele of a (TAA)(n) marker demonstrated excess transmission to affected individuals; SNP21 and haplotypes SNP2-(CTG)(n) and SNP12-SNP2-(CTG)(n) also showed significant associations. In an attempt to replicate these findings, we tested for linkage and association between the same five markers used by Wei and Hemmings in 166 families collected from a multi-center study conducted by the Department of Veterans Affairs (DVA) Cooperative Study Program (CSP). The families include 392 affected subjects (schizophrenia or schizoaffective disorder, depressed) and 216 affected sibling pairs. The families represent a mix of European Americans (n = 62, 37%), African Americans (n = 60, 36%), and racially mixed or other races (n = 44, 27%). We identified moderate evidence for linkage in the pooled race sample (LOD = 1.25) and found excess transmission of the 8 (P = 0.06) and 13 (P = 0.04) repeat alleles of the (TAA)(n) marker to African American schizophrenic subjects. The 8 and 13 repeat alleles were previously identified to be positively associated with schizophrenia by Wei and Hemmings [2000: Nat Genet 25:376-377] and Sklar et al. [2001: Nat Genet 28:126-128], respectively.

Dynamic expression of mRNAs and proteins for matrix metalloproteinases and their tissue inhibitors in the primate corpus luteum during the menstrual cycle

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) may be involved in tissue remodelling in the primate corpus luteum (CL). MMP/TIMP mRNA and protein patterns were examined using real-time PCR and immunohistochemistry in the early, mid-, mid-late, late and very late CL of rhesus monkeys. MMP-1 (interstitial collagenase) mRNA expression peaked (by >7-fold) in the early CL. MMP-9 (gelatinase B) mRNA expression was low in the early CL, but increased 41-fold by the very late stage. MMP-2 (gelatinase A) mRNA expression tended to increase in late CL. TIMP-1 mRNA was highly expressed in the CL, until declining 21-fold by the very late stage. TIMP-2 mRNA expression was high through the mid-luteal phase. MMP-1 protein was detected by immunocytochemistry in early steroidogenic cells. MMP-2 protein was prominent in late, but not early CL microvasculature. MMP-9 protein was noted in early CL and labelling increased in later stage steroidogenic cells. TIMP-1 and -2 proteins were detected in steroidogenic cells at all stages. Thus, MMPs and TIMPs are dynamically expressed in a cell-specific manner in the primate CL. Early expression of MMP-1 is suggestive of a role in tissue remodelling associated with luteinization, whereas MMP-2 and -9 may contribute to later stage luteolysis. TIMP expression may control MMP activity, until declining at luteolysis.

Linkage of chromosome 13q32 to schizophrenia in a large veterans affairs cooperative study sample

Several prior reports have suggested that chromosomal region 13q32 may harbor a schizophrenia susceptibility gene. In an attempt to replicate this finding, we assessed linkage between chromosome 13 markers and schizophrenia in 166 families, each with two or more affected members. The families, assembled from multiple centers by the Department of Veterans Affairs Cooperative Studies Program, included 392 sampled affected subjects and 216 affected sib pairs. By DSM-III-R criteria, 360 subjects (91.8%) had a diagnosis of schizophrenia and 32 (8.2%) were classified as schizoaffective disorder, depressed. The families had mixed ethnic backgrounds. The majority were northern European-American families (n = 62, 37%), but a substantial proportion were African-American kindreds (n = 60, 36%). Chromosome 13 markers, spaced at intervals of approximately 10 cM over the entire chromosome and 2-5 cM for the 13q32 region were genotyped and the data analyzed using semi-parametric affected only linkage analysis. For the combined sample (with race broadly defined and schizophrenia narrowly defined) the maximum LOD score was 1.43 (Z-score of 2.57; P = 0.01) at 79.0 cM between markers D13S1241 (76.3 cM) and D13S159 (79.5 cM). Both ethnic groups showed a peak in this region. The peak is within 3 cM of the peak reported by Brzustowicz et al. [1999: Am J Hum Genet 65:1096-1103].