Andrej Marusic

Increased BDNF Promoter Methylation in the Wernicke Area of Suicide Subjects

CONTEXT Brain-derived neurotrophic factor (BDNF) plays a pivotal role in the pathophysiology of suicidal behavior and BDNF levels are decreased in the brain and plasma of suicide subjects. So far, the mechanisms leading to downregulation of BDNF expression are poorly understood. OBJECTIVES To test the hypothesis that alterations of DNA methylation could be involved in the dysregulation of BDNF gene expression in the brain of suicide subjects. DESIGN Three independent quantitative methylation techniques were performed on postmortem samples of brain tissue. BDNF messenger RNA levels were determined by quantitative real-time polymerase chain reaction. SETTING Academic medical center. PATIENTS OR OTHER PARTICIPANTS Forty-four suicide completers and 33 nonsuicide control subjects of white ethnicity. MAIN OUTCOME MEASURES The DNA methylation degree at BDNF promoter IV and the genome-wide DNA methylation levels in the brains Wernicke area. RESULTS Postmortem brain samples from suicide subjects showed a statistically significant increase of DNA methylation at specific CpG sites in BDNF promoter/exon IV compared with nonsuicide control subjects (P < .001). Most of the CpG sites lying in the -300/+500 region, on both strands, had low or no methylation, with the exception of a few sites located near the transcriptional start site that had differential methylation, while genome-wide methylation levels were comparable among the subjects. The mean methylation degree at the 4 CpG sites analyzed by pyrosequencing was always less than 12.9% in the 33 nonsuicide control subjects, while in 13 of 44 suicide victims (30%), the mean methylation degree ranged between 13.1% and 34.2%. Higher methylation degree corresponded to lower BDNF messenger RNA levels. CONCLUSIONS BDNF promoter/exon IV is frequently hypermethylated in the Wernicke area of the postmortem brain of suicide subjects irrespective of genome-wide methylation levels, indicating that a gene-specific increase in DNA methylation could cause or contribute to the downregulation of BDNF expression in suicide subjects. The reported data reveal a novel link between epigenetic alteration in the brain and suicidal behavior.

Differential efficacy of escitalopram and nortriptyline on dimensional measures of depression

BACKGROUND Tricyclic antidepressants and serotonin reuptake inhibitors are considered to be equally effective, but differences may have been obscured by internally inconsistent measurement scales and inefficient statistical analyses. AIMS To test the hypothesis that escitalopram and nortriptyline differ in their effects on observed mood, cognitive and neurovegetative symptoms of depression. METHOD In a multicentre part-randomised open-label design (the Genome Based Therapeutic Drugs for Depression (GENDEP) study) 811 adults with moderate to severe unipolar depression were allocated to flexible dosage escitalopram or nortriptyline for 12 weeks. The weekly Montgomery-Asberg Depression Rating Scale, Hamilton Rating Scale for Depression, and Beck Depression Inventory were scored both conventionally and in a more novel way according to dimensions of observed mood, cognitive symptoms and neurovegetative symptoms. RESULTS Mixed-effect linear regression showed no difference between escitalopram and nortriptyline on the three original scales, but symptom dimensions revealed drug-specific advantages. Observed mood and cognitive symptoms improved more with escitalopram than with nortriptyline. Neurovegetative symptoms improved more with nortriptyline than with escitalopram. CONCLUSIONS The three symptom dimensions provided sensitive descriptors of differential antidepressant response and enabled identification of drug-specific effects.

Suicide methods in Europe: a gender-specific analysis of countries participating in the ''European Alliance Against Depression''

Objective: To identify the most frequent gender-specific suicide methods in Europe. Design: Proportions of seven predominant suicide methods utilised in 16 countries participating in the European Alliance Against Depression (EAAD) were reported in total and cross-nationally. Relative risk (RR) relating to suicide methods and gender was calculated. To group countries by pattern of suicide methods, hierarchical clustering was applied. Setting and participants: Data on suicide methods for 119 122 male and 41 338 female cases in 2000–4/5 from 16 EAAD countries, covering 52% of European population were obtained. Results: Hanging was the most prevalent suicide method among both males (54.3%) and females (35.6%). For males, hanging was followed by firearms (9.7%) and poisoning by drugs (8.6%); for females, by poisoning by drugs (24.7%) and jumping from a high place (14.5%). Only in Switzerland did hanging rank as second for males after firearms. Hanging ranked first among females in eight countries, poisoning by drugs in five and jumping from a high place in three. In all countries, males had a higher risk than females of using firearms and hanging and a lower risk of poisoning by drugs, drowning and jumping. Grouping showed that countries might be divided into five main groups among males; for females, grouping did not yield clear results. Conclusions: Research on suicide methods could lead to the development of gender-specific intervention strategies. Nevertheless, other approaches, such as better identification and treatment of mental disorders and the improvement of toxicological aid should be put in place.

Suicide attempts in the United States: The role of physical illness.

The study aimed to determine the relationship between physical illness, mental disorder, and the likelihood of suicide attempt among adults aged 15-54 in the United States. Data were drawn from the National Comorbidity Survey (N=8,098), a national probability sample of adults in the United States. Multivariate logistic regression analyses were used to determine the relationship between self-reported physical illness and the likelihood of suicide attempt. Lung disease (OR=1.8 (1.1, 2.7)), ulcer (OR=2.1 (1.3, 3.4)), and AIDS (OR=44.1 (10.5, 185.6)) were each associated with a significantly increased likelihood of suicide attempt, independent of the effects of mental disorders. Consistent with previous studies, the number of physical illnesses was linearly related to an increased odds of suicide attempt (OR=1.3 (1.2, 1.5)). Possible mechanisms for these associations are discussed. These findings call for the inclusion of a range of physical health problems, especially chronic illnesses, in future research on suicide attempts in the population.

What can psychiatric genetics offer suicidology

There is good evidence from recent studies that depression is familial, and that a substantial proportion of the variation in liability is explained by genes. Suicidal behavior, including completed suicide, also seems to cluster in families. First-degree relatives of individuals who have committed suicide (included dizygotic twins) have more than twice the risk of the general population. For identical co-twins of suicides, the relative risk increases to about 11. Applying a simple structural equation model to the published data suggests a heritability for completed suicide of about 43% (95% confidence intervals 25-60). It is not known at present whether the genes predisposing to suicide are identical with those predisposing to affective disorder, but since only about half of those committing suicide have a diagnosis of depression, it seems probable that the overlap is incomplete. The mode of inheritance of suicidal behavior is almost certain to be complex, involving many genes. There have already been some initial studies of allelic association with polymorphisms in candidate genes such as those involved in serotonergic transmission. Further progress is likely to come from candidate gene and linkage disequilibrium studies that are capable of detecting multiple genes of small effect.

Genetic Predictors of Increase in Suicidal Ideation During Antidepressant Treatment in the GENDEP Project

The aim of this study was to investigate genetic predictors of an increase in suicidal ideation during treatment with a selective serotonin reuptake inhibitor or a tricyclic antidepressant. A total of 796 adult patients with major depressive disorder who were treated with a flexible dosage of escitalopram or nortriptyline in Genome-based Therapeutic Drugs for Depression (GENDEP) were included in the sample and provided data on suicidal ideation. Nine candidate genes involved in neurotrophic, serotonergic, and noradrenergic pathways were selected based on previous association studies with suicidal ideation or behavior. Using a logistic regression model, 123 polymorphisms in these genes were compared between subjects with an increase in suicidal ideation and those without any increase in suicidal ideation. Polymorphisms in BDNF, the gene encoding the brain-derived neurotrophic factor, were significantly associated with an increase in suicidal ideation. The strongest association was observed for rs962369 in BDNF (p=0.0015). Moreover, a significant interaction was found between variants in BDNF and NTRK2, the gene encoding the BNDF receptor (p=0.0003). Among men taking nortriptyline, suicidality was also associated with rs11195419 SNP in the alpha2A-adrenergic receptor gene (ADRA2A) (p=0.007). The associations observed with polymorphisms in BDNF suggest the involvement of the neurotrophic system in vulnerability to suicidality. Epistasis between BDNF and NTRK2 suggests that genetic variations in the two genes are involved in the same causal mechanisms leading to suicidality during antidepressant treatment. Among men, genetic variation in noradrenergic signaling may interact with norepinephrine reuptake-inhibiting antidepressants, thereby contributing to suicidality.

Genome-wide scan for genes involved in bipolar affective disorder in 70 European families ascertained through a bipolar type I early-onset proband: supportive evidence for linkage at 3p14.

Preliminary studies suggested that age at onset (AAO) may help to define homogeneous bipolar affective disorder (BPAD) subtypes. This candidate symptom approach might be useful to identify vulnerability genes. Thus, the probability of detecting major disease-causing genes might be increased by focusing on families with early-onset BPAD type I probands. This study was conducted as part of the European Collaborative Study of Early Onset BPAD (France, Germany, Ireland, Scotland, Switzerland, England, Slovenia). We performed a genome-wide search with 384 microsatellite markers using non-parametric linkage analysis in 87 sib-pairs ascertained through an early-onset BPAD type I proband (AAO of 21 years or below). Non-parametric multipoint analysis suggested eight regions of linkage with P-values<0.01 (2p21, 2q14.3, 3p14, 5q33, 7q36, 10q23, 16q23 and 20p12). The 3p14 region showed the most significant linkage (genome-wide P-value estimated over 10 000 simulated replicates of 0.015 [0.01–0.02]). After genome-wide search analysis, we performed additional linkage analyses with increased marker density using markers in four regions suggestive for linkage and having an information contents lower than 75% (3p14, 10q23, 16q23 and 20p12). For these regions, the information content improved by about 10%. In chromosome 3, the non-parametric linkage score increased from 3.51 to 3.83. This study is the first to use early-onset bipolar type I probands in an attempt to increase sample homogeneity. These preliminary findings require confirmation in independent panels of families.

The role of impulsivity in self-mutilators, suicide ideators and suicide attempters — A study of 1265 male incarcerated individuals

OBJECTIVE We explored differences between high and low-impulsive incarcerated individuals in the context of lifetime self-mutilation, suicide ideation and suicide attempt. METHODS A total of 1265 males detained in Italian penitentiary institutions were studied between January 2006 and December 2008. The study raters were specifically trained to discriminate between suicide attempters, ideators and self-mutilators. Participants completed the Barratt Impulsivity Scale, Childhood Trauma Questionnaire (CTQ), Eysenck Personality Questionnaire (EPQ), Connor-Davidson Resilience Scale (CD-RISC), Brown-Goodwin Assessment for Lifetime History of Aggression (BGLHA) and Buss and Durkee Hostility Inventory (BDHI). Based on BIS 7 total score distribution, two extreme quarters - high-impulsive group (n=306) and low-impulsive group (n=285) - were compared. RESULTS Over 42% of participants had lifetime suicide ideation, 13% attempted suicide and 17% were self-mutilators. High-impulsive subjects were younger, more often single and with more prominent psychoticism, extraversion, aggression, hostility and resilience capacity. They were more frequently diagnosed with substance use disorders and engaged in self-mutilating behaviour. There was no difference in the rate of suicide attempts between the two groups. CONCLUSION Although high-impulsive subjects were more prone to suicidal behaviour, it was not predicted by higher impulsivity when other psychological variables were accounted for.

Brain derived neurotrophic factor (BDNF) genetic polymorphism (Val66Met) in suicide: a study of 512 cases.

Brain Derived Neurotrophic Factor (BDNF) Genetic Polymorphism (Val66Met) in Suicide: A Study of 512 Cases F. Zarrilli, A. Angiolillo, G. Castaldo, L. Chiariotti, S. Keller, S. Sacchetti, A. Marusic, T. Zagar, V. Carli, A. Roy, and M. Sarchiapone* Facolt a di Scienze MFN, Universit a del Molise, Isernia, Italy Dipartimento di Biochimica e Biotecnologie Mediche and Facolt a di Scienze Biotecnologiche, Universit a ‘‘Federico II’’, CEINGE-Biotecnologie Avanzate, Naples, Italy Dipartimento di Biologia e Patologia Cellulare e Molecolare, Universit a ‘‘Federico II’’, CEINGE-Biotecnologie Avanzate, Naples, Italy University of Primorska, Primorska, Slovenia Department of Health Sciences, University of Molise, Campobasso, Italy Psychiatry Service, Department of Veteran Affairs, Newark, New Jersey

CYP2C19 genotype predicts steady state escitalopram concentration in GENDEP

In vitro work shows CYP2C19 and CYP2D6 contribute to the metabolism of escitalopram to its primary metabolite, N-desmethylescitalopram. We report the effect of CYP2C19 and CYP2D6 genotypes on steady state morning concentrations of escitalopram and N-desmethylescitalopram and the ratio of this metabolite to the parent drug in 196 adult patients with depression in GENDEP, a clinical pharmacogenomic trial. Subjects who had one CYP2D6 allele associated with intermediate metabolizer phenotype and one associated with poor metabolizer (i.e. IM/PM genotypic category) had a higher mean logarithm escitalopram concentration than CYP2D6 extensive metabolizers (EMs) (p = 0.004). Older age was also associated with higher concentrations of escitalopram. Covarying for CYP2D6 and age, we found those homozygous for the CYP2C19*17 allele associated with ultrarapid metabolizer (UM) phenotype had a significantly lower mean escitalopram concentration (2-fold, p = 0.0001) and a higher mean metabolic ratio (p = 0.0003) than EMs, while those homozygous for alleles conferring the PM phenotype had a higher mean escitalopram concentration than EMs (1.55-fold, p = 0.008). There was a significant overall association between CYP2C19 genotypic category and escitalopram concentration (p = 0.0003; p = 0.0012 Bonferroni corrected). In conclusion, we have demonstrated an association between CYP2C19 genotype, including the CYP2C19*17 allele, and steady state escitalopram concentration.