Longitudinal analyses of the DNA methylome in deployed military servicemen identify susceptibility loci for post-traumatic stress disorder.

In order to determine the impact of the epigenetic response to traumatic stress on post-traumatic stress disorder (PTSD), this study examined longitudinal changes of genome-wide blood DNA methylation profiles in relation to the development of PTSD symptoms in two prospective military cohorts (one discovery and one replication data set). In the first cohort consisting of male Dutch military servicemen (n=93), the emergence of PTSD symptoms over a deployment period to a combat zone was significantly associated with alterations in DNA methylation levels at 17 genomic positions and 12 genomic regions. Evidence for mediation of the relation between combat trauma and PTSD symptoms by longitudinal changes in DNA methylation was observed at several positions and regions. Bioinformatic analyses of the reported associations identified significant enrichment in several pathways relevant for symptoms of PTSD. Targeted analyses of the significant findings from the discovery sample in an independent prospective cohort of male US marines (n=98) replicated the observed relation between decreases in DNA methylation levels and PTSD symptoms at genomic regions in ZFP57, RNF39 and HIST1H2APS2. Together, our study pinpoints three novel genomic regions where longitudinal decreases in DNA methylation across the period of exposure to combat trauma marks susceptibility for PTSD.

Largest GWAS of PTSD (N=20 070) yields genetic overlap with schizophrenia and sex differences in heritability.

The Psychiatric Genomics Consortium-Posttraumatic Stress Disorder group (PGC-PTSD) combined genome-wide case-control molecular genetic data across 11 multiethnic studies to quantify PTSD heritability, to examine potential shared genetic risk with schizophrenia, bipolar disorder, and major depressive disorder and to identify risk loci for PTSD. Examining 20 730 individuals, we report a molecular genetics-based heritability estimate (h2SNP) for European-American females of 29% that is similar to h2SNP for schizophrenia and is substantially higher than h2SNP in European-American males (estimate not distinguishable from zero). We found strong evidence of overlapping genetic risk between PTSD and schizophrenia along with more modest evidence of overlap with bipolar and major depressive disorder. No single-nucleotide polymorphisms (SNPs) exceeded genome-wide significance in the transethnic (overall) meta-analysis and we do not replicate previously reported associations. Still, SNP-level summary statistics made available here afford the best-available molecular genetic index of PTSD-for both European- and African-American individuals-and can be used in polygenic risk prediction and genetic correlation studies of diverse phenotypes. Publication of summary statistics for ∼10 000 African Americans contributes to the broader goal of increased ancestral diversity in genomic data resources. In sum, the results demonstrate genetic influences on the development of PTSD, identify shared genetic risk between PTSD and other psychiatric disorders and highlight the importance of multiethnic/racial samples. As has been the case with schizophrenia and other complex genetic disorders, larger sample sizes are needed to identify specific risk loci.

Dehydroepiandrosterone and dehydroepiandrosterone sulfate levels in combat veterans with or without a history of suicide attempt.

OBJECTIVE: The goal of this study was to determine whether combat veterans who have made a suicide attempt postdeployment can be distinguished from combat veterans who have never made a suicide attempt based on differences in psychological and biological variables. METHODS: Demographic and clinical parameters of suicide attempters and non-attempters were assessed. Blood samples were assayed for dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS). RESULTS: Suicide attempters had higher Scale for Suicidal Ideation and Montgomery-Åsberg Depression Rating Scale (MADRS)-suicidal thoughts item scores in comparison with non-attempters. There was a trend toward higher MADRS scores in the suicide attempter group compared with non-attempters. Suicide attempters had significantly lower levels of DHEA and DHEAS compared with non-attempters. Scale for Suicidal Ideation scores in all study participants combined negatively correlate with DHEA and DHEAS levels. DHEAS levels negatively correlate with Scale for Suicidal Ideation scores in suicide non-attempters but not in suicide attempters. DHEA/DHEAS ratios positively correlate with total adolescence aggression scores, total adulthood aggression scores, and total aggression scale scores in suicide attempters but not in suicide non-attempters. CONCLUSION: There are psychobiological differences between combat veterans with or without a history of suicidal behaviour.

Near IR fluorescent conjugated poly(ethylene glycol)bisphosphonate nanoparticles for in vivo bone targeting in a young mouse model.

Bisphosphonate (BP) compounds are widely used in the treatment of bone disorders. This group of drugs with a high affinity to Ca(+2) ions is rapidly attracted to bone mineral, especially in areas of high resorption. We have engineered unique biodegradable BP nanoparticles (NPs) by dispersion co-polymerization of the monomers methacrylate-PEG-BP) and (3-Aminopropyl)mathacrylamide) with the crosslinker monomer tetra ethylene glycol diacrylate. These NPs possess a dual functionality: (1) covalent attachment of a dye (e.g. near IR dye) or a drug to the nanoparticles through the primary amine groups on the surface of the NPs; (2) chelation to the bone mineral hydroxyapatite through the BP on the surface of the NPs. This study describes the uptake of the unique near IR fluorescent Cy 7-conjugated BP NPs in bone of a young mouse model. Blood half-life studies revealed a relatively long half-life (approximately 5 h) due to a high concentration of PEG in the BP NPs as well as a relatively long whole body clearance (approximately 2 weeks). Body distribution studies showed a specific uptake of the BP NPs in bone. These unique engineered BP NPs are planned to be utilized in future work for diagnostic and drug delivery systems that are targeted to bone disorders.

Ten-year follow-up study of PTSD diagnosis, symptom severity and psychosocial indices in aging holocaust survivors.

OBJECTIVE: We performed a longitudinal study of holocaust survivors with and without post-traumatic stress disorder (PTSD) by assessing symptoms and other measures at two intervals, approximately 10 years apart. METHOD: The original cohort consisted of 63 community-dwelling subjects, of whom 40 were available for follow-up. RESULTS: There was a general diminution in PTSD symptom severity over time. However, in 10% of the subjects (n=4), new instances of delayed onset PTSD developed between time 1 and time 2. Self-report ratings at both assessments revealed a worsening of trauma-related symptoms over time in persons without PTSD at time 1, but an improvement in those with PTSD at time 1. CONCLUSION: The findings suggest that a nuanced characterization of PTSD trajectory over time is more reflective of PTSD symptomatology than simple diagnostic status at one time. The possibility of delayed onset trajectory complicates any simplistic overall trajectory summarizing the longitudinal course of PTSD.

A portable bio-impedance system for monitoring lung resistivity.

The principles of a hybrid bio-impedance technique are implemented in a novel, lung resistivity monitoring system ("CardioInspect" Tel-Aviv University, Israel). The system is to be utilized in the clinic or at home, for daily monitoring of patients suffering from pulmonary edema. The developed system consists of an eight-electrode belt worn around the thorax, an electronic unit containing analog and digital boards, and a stand-alone DSP based system with a designated software to analyze the data. A Newton-Raphson algorithm based on the finite-volume method is employed for the optimization of the left and right lung resistivity values, making use of the voltage measurements retrieved from opposite current injections. In this preliminary study, 33 healthy volunteers were measured with the system during tidal respiration, yielding symmetric mean left and right lung resistivity values of (1205+/-163, 1200+/-165) (Omega cm). The system reproducibility was better than 2% for both within and between tests measurements, and no dependency between the reconstructed values and various anthropometric parameters was found.

Gene expression associated with suicide attempts in US veterans.

According to a recent report from the Office of Suicide Prevention in the US Department of Veterans Affairs, veterans represent 8.5% of the US population, but account for 18% of all deaths from suicide. The aim of this study of psychiatric patients (n=39; 87% male) was to compare blood gene expression data from veterans with a history of one or more suicide attempts to veterans who had never attempted suicide. The attempter and non-attempter groups were matched for age and race/ethnicity, and both groups included veterans with a diverse psychiatric history that included posttraumatic stress disorder (PTSD) and substance-use disorders. Veterans were interviewed for lifetime psychiatric history, including a detailed assessment of prior suicide attempts and provided a blood sample. Results of Ingenuity Pathway Analysis (IPA) identified several pathways associated with suicide attempts, including the mammalian target of rapamycin (mTOR) and WNT signaling pathways. These pathways are of particular interest, given their role in explaining pharmacological treatments for suicidal behavior, including the use of ketamine and lithium. These results suggest that findings observed in civilians are also relevant for veterans and provide a context for interpreting results observed in post-mortem samples. In conclusion, an emerging body of work that shows consistency in findings across blood and brain samples suggests that it might be possible to identify molecular predictors of suicide attempts.

Utilization of machine learning for prediction of post-traumatic stress: a re-examination of cortisol in the prediction and pathways to non-remitting PTSD.

To date, studies of biological risk factors have revealed inconsistent relationships with subsequent post-traumatic stress disorder (PTSD). The inconsistent signal may reflect the use of data analytic tools that are ill equipped for modeling the complex interactions between biological and environmental factors that underlay post-traumatic psychopathology. Further, using symptom-based diagnostic status as the group outcome overlooks the inherent heterogeneity of PTSD, potentially contributing to failures to replicate. To examine the potential yield of novel analytic tools, we reanalyzed data from a large longitudinal study of individuals identified following trauma in the general emergency room (ER) that failed to find a linear association between cortisol response to traumatic events and subsequent PTSD. First, latent growth mixture modeling empirically identified trajectories of post-traumatic symptoms, which then were used as the study outcome. Next, support vector machines with feature selection identified sets of features with stable predictive accuracy and built robust classifiers of trajectory membership (area under the receiver operator characteristic curve (AUC)=0.82 (95% confidence interval (CI)=0.80-0.85)) that combined clinical, neuroendocrine, psychophysiological and demographic information. Finally, graph induction algorithms revealed a unique path from childhood trauma via lower cortisol during ER admission, to non-remitting PTSD. Traditional general linear modeling methods then confirmed the newly revealed association, thereby delineating a specific target population for early endocrine interventions. Advanced computational approaches offer innovative ways for uncovering clinically significant, non-shared biological signals in heterogeneous samples.

Whole-genome DNA methylation status associated with clinical PTSD measures of OIF/OEF veterans.

Emerging knowledge suggests that post-traumatic stress disorder (PTSD) pathophysiology is linked to the patients' epigenetic changes, but comprehensive studies examining genome-wide methylation have not been performed. In this study, we examined genome-wide DNA methylation in peripheral whole blood in combat veterans with and without PTSD to ascertain differentially methylated probes. Discovery was initially made in a training sample comprising 48 male Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) veterans with PTSD and 51 age/ethnicity/gender-matched combat-exposed PTSD-negative controls. Agilent whole-genome array detected ~5600 differentially methylated CpG islands (CpGI) annotated to ~2800 differently methylated genes (DMGs). The majority (84.5%) of these CpGIs were hypermethylated in the PTSD cases. Functional analysis was performed using the DMGs encoding the promoter-bound CpGIs to identify networks related to PTSD. The identified networks were further validated by an independent test set comprising 31 PTSD+/29 PTSD- veterans. Targeted bisulfite sequencing was also used to confirm the methylation status of 20 DMGs shown to be highly perturbed in the training set. To improve the statistical power and mitigate the assay bias and batch effects, a union set combining both training and test set was assayed using a different platform from Illumina. The pathways curated from this analysis confirmed 65% of the pool of pathways mined from training and test sets. The results highlight the importance of assay methodology and use of independent samples for discovery and validation of differentially methylated genes mined from whole blood. Nonetheless, the current study demonstrates that several important epigenetically altered networks may distinguish combat-exposed veterans with and without PTSD.

Dose-response changes in plasma cortisol and lymphocyte glucocorticoid receptors following dexamethasone administration in combat veterans with and without posttraumatic stress disorder.

BACKGROUND: Our previous studies have suggested that combat veterans with posttraumatic stress disorder (PTSD) have alterations in hypothalamic-pituitary-adrenal axis functioning that are different from the well-documented biological changes observed in major depressive disorder and following exposure to stress. METHODS: In the present study, we examined cortisol and lymphocyte glucocorticoid receptor number before and after the administration of 0.50 and 0.25 mg of dexamethasone in 14 combat veterans with PTSD, 12 combat veterans without PTSD, and 14 nonpsychiatric healthy men. All subjects were medication free at the time of testing and none met diagnostic criteria for major depression or substance dependence. RESULTS: Combat veterans with PTSD suppressed cortisol to a greater extent than did combat veterans without PTSD and normal controls in response to both doses of dexamethasone. Differences in cortisol suppression could not be attributed to substance dependence history or differences in dexamethasone bioavailability. Combat veterans with PTSD showed a larger number of baseline glucocorticoid receptors compared with normal men. Combat veterans without PTSD also had a larger number of baseline glucocorticoid receptors compared with normal men and in fact were comparable to combat veterans with PTSD on this measure. However, only veterans with PTSD showed a decrease in lymphocyte glucocorticoid receptor number following dexamethasone administration. CONCLUSION: The data support the hypothesis of an enhanced negative feedback sensitivity of the hypothalamic-pituitary-adrenal axis in PTSD.

Elevation of serum free triiodothyronine, total triiodothyronine, thyroxine-binding globulin, and total thyroxine levels in combat-related posttraumatic stress disorder.

BACKGROUND: This study was designed to assess both central and peripheral aspects of thyroid function in combat-related posttraumatic stress disorder (PTSD), with the particular purpose of finding a mechanistic explanation for an imbalance between serum levels of free thyroxine (T4) and total T4 previously observed in pilot work. METHODS: A total of 96 male combat veterans with PTSD diagnosed by DSM-III-R (72 from the West Haven, Conn, Veterans Affairs Medical Center and 24 from the Menlo Park, Calif, Veterans Affairs Medical Center) were compared with 24 male control subjects. One or more serum samples were analyzed by radioimmunoassays for levels of total T4, free T4, total triiodothyronine (T3), free T3, T4-binding globulin, and thyrotropin. RESULTS: The pilot observation of moderately elevated total T4 levels with no elevation in free T4 levels in patients with PTSD was confirmed, suggesting the hypotheses that (1) there may be an increased peripheral conversion of free T4 by deiodination to T3 or (2) there may be an increased binding of T4 secondary to elevated T4-binding globulin levels. Our findings support both hypotheses. The PTSD groups all showed a marked and sustained elevation in levels of both total T3 and free T3, as well as elevated T3/T4 ratios, supporting the increased T3 conversion hypothesis. The PTSD groups also showed a marked and sustained increase in T4-binding globulin levels, supporting the increased binding hypothesis. Thyrotropin levels did not differ between PTSD and control groups. CONCLUSIONS: These findings demonstrate an unusual pattern of thyroid alterations, featuring substantial elevations in total T3, free T3, and T4-binding globulin levels, in combat-related PTSD that differs from established endocrinopathies, such as classic hyperthyroidism, T3 thyrotoxicosis, or chronic T4-binding globulin elevation.

Neuroendocrine aspects of PTSD.

This chapter discussed how neuroendocrine findings in posttraumatic stress disorder (PTSD) potentially inform hypothalamic-pituitary-adrenal (HPA) alterations in PTSD and highlight alterations relevant to the identification of targets for drug development. Most studies demonstrate alterations consistent with an enhanced negative feedback inhibition of cortisol on the pituitary, an overall hyperreactivity of other target tissues (adrenal gland, hypothalamus), or both in PTSD. However, findings of low cortisol and increased reactivity of the pituitary in PTSD are also consistent with reduced adrenal output. The observations in PTSD are part of a growing body of neuroendocrine data providing evidence of insufficient glucocorticoid signaling in stress-related neuropsychiatric disorders.

Influence of visible light and ultraviolet irradiation on motility and fertility of mammalian and fish sperm.

OBJECTIVE: The effects of visible light irradiation on sperm motility, fertility, and reactive oxygen species (ROS) formation were investigated and compared in ram and fish (tilapia). BACKGROUND DATA: Low-energy visible light has previously been found to modulate various processes in different biological systems. In the literature, it is accepted that the first step following visible light irradiation is the formation of ROS by endogenous cellular photosensitizers. METHODS: Sperm of ram and tilapia were irradiated with various light sources (400-800 nm white light, 660 nm red light, 360 nm blue light, 294 nm UV), and their motility and fertility rates were measured. The amount of ROS generated by irradiation was estimated using electron paramagnetic resonance (EPR) technique. RESULTS: Sperm taken from tilapia showed higher motility and fertility following red and white light irradiation. In contrast, the motility and fertility of ram sperm were slightly increased only by red light. A negative effect on motility and fertility of sperm of both species was obtained following irradiation with UV and blue light. The amount of ROS produced in irradiated tilapia sperm was much higher than that of ram sperm. CONCLUSIONS: The results show that different wavelengths differentially affect tilapia and ram sperm motility and fertilization. The difference in response to the various light sources might be explained by the different amounts of ROS formation by ram and tilapia, which are in agreement with the physiology of fertilization appropriate to each of these species. Based on these results, it is suggested that in vitro fertilization in mammals should be performed in darkness or at least under red light.

Criteria for rationally evaluating animal models of posttraumatic stress disorder.

Animal models of stress have the potential to provide information about the course and etiology of posttraumatic stress disorder (PTSD). To date, however, there have been no systematic approaches for evaluating the relevance of animal models of stress to PTSD. It has been established in the animal literature that different types of stress paradigms lead to different biobehavioral consequences and that many different factors contribute to differential responsivity to stress. It becomes important therefore to differentiate between factors that are essential to the induction of PTSD-like symptoms and those that influence their manifestations. In the present commentary, we present five criteria that must be fulfilled by animal models of stress for them to be useful to understanding the induction of PTSD. We then evaluate two potential animal models of stress--inescapable shock-learned helplessness and time-dependent sensitization--to illustrate how to more successfully pair animal models of stress with the specific clinical syndrome of PTSD.

Predicting the development of posttraumatic stress disorder from the acute response to a traumatic event.

Posttraumatic stress disorder (PTSD) is a psychiatric condition that is directly precipitated by an event that threatens a person's life or physical integrity and that invokes a response of fear, helplessness, or horror. In recent years it has become clear that only a proportion of those exposed to fear-producing events develop or sustain PTSD. Thus, it seems that an important challenge is to elucidate aberrations in the normal fear response that might precipitate trauma-related psychiatric disorder. This paper summarizes the findings from recent studies that examined the acute and longer term biological response to traumatic stress in people appearing to the emergency room immediately following trauma exposure. In the aggregate, these studies have demonstrated increased heart rate and lower cortisol levels at the time of the traumatic event in those who have PTSD at a follow-up time compared to those who do not. In contrast, certain features associated with PTSD, such as intrusive symptoms and exaggerated startle responses, are only manifest weeks after the trauma. The findings suggest that the development of PTSD may be facilitated by an atypical biological response in the immediate aftermath of a traumatic event, which in turn leads to a maladaptive psychological state.

Glucocorticoid receptor number and cortisol excretion in mood, anxiety, and psychotic disorders.

In the present study, we measured cytosolic lymphocyte glucocorticoid receptor and 24-hour urinary cortisol excretion in patients with major depressive disorder, bipolar mania, posttraumatic stress disorder, panic disorder, and schizophrenia. Patients with major depression had the smallest, and posttraumatic stress disordered patients the largest, mean number of glucocorticoid receptors per cell compared to patients in the other groups. Bipolar manic and panic patients did not differ from each other in regard to the number of lymphocyte glucocorticoid receptors. Bipolar manic and panic patients did have significantly more glucocorticoid receptors/cell than schizophrenic patients. The mean 24-hour urinary cortisol excretion was significantly higher in patients with major depression and bipolar mania than in those in the other diagnostic groups. Lymphocyte glucocorticoid receptor number and cortisol excretion tended to be inversely related, when the entire sample was considered as a whole, but this effect did not reach statistical significance. It is concluded that lymphocyte glucocorticoid receptors may be modulated by multiple influences, not just ambient cortisol levels. These preliminary data suggest that the assessment of lymphocyte glucocorticoid receptor number in tandem with cortisol levels may provide a more meaningful estimate of hypothalamic-pituitary-adrenal axis activity than is achieved using cortisol alone.

Enhanced dexamethasone suppression of plasma cortisol in adult women traumatized by childhood sexual abuse.

A study was undertaken to determine if female survivors of childhood and/or adolescent sexual abuse (CSA) would exhibit hypothalamic-pituitary-adrenal (HPA) axis abnormalities characteristic of patients with combat-related posttraumatic stress disorder (PTSD)--i.e., enhanced cortisol suppression to low-dose dexamethasone and increased density of lymphocyte glucocorticoid receptors. Nineteen women who reported experiencing severe CSA and 21 nonvictimized women participated in a low-dose (0.5 mg) dexamethasone suppression test and donated blood for measurement of lymphocyte glucocorticoid receptor binding. Women with CSA had significantly enhanced suppression of plasma cortisol in response to 0.5 mg dexamethasone compared to the nonvictimized women. These observations are consistent with findings in male veterans with combat-related PTSD. They suggest that this pattern of HPA axis dysfunction may be a characteristic sequel of psychiatric disorders that occur following a range of traumatic experiences. This HPA axis profile is different than that associated with acute stress or with major depressive disorder.

Relationship between 3-methoxy-4-hydroxyphenylglycol and homovanillic acid in saliva and plasma of healthy volunteers.

Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) levels may reflect changes in central noradrenergic and dopaminergic activity, respectively. The relationship between MHPG and HVA in saliva and plasma was investigated to evaluate the utility of salivary metabolite measurement as a relatively noninvasive and useful alternative to plasma analysis. MHPG and HVA in saliva and plasma, collected concurrently, from 12 healthy volunteers, were measured by high-performance liquid chromatography. Concentration of free MHPG in saliva correlated significantly with plasma free MHPG. Salivary free MHPG was significantly higher than in plasma. Enzymatic hydrolysis of conjugated MHPG corroborated other work that plasma free MHPG, MHPG-glucuronide, and MHPG-sulfate were in roughly equal proportions. Unpredictably, in saliva, free MHPG was greater than 80% of the total. Salivary and plasma free HVA concentrations also correlated significantly, but salivary HVA levels were significantly lower than in plasma. Conjugated HVA was consistently less than 10% of total both in saliva and plasma. These findings suggest that salivary MHPG and HVA can reflect plasma metabolite levels. Although local factors may influence their formation and concentration in saliva, large changes in plasma free MHPG or HVA could be reflected by parallel changes in saliva.

Prolactin response to low-dose dexamethasone challenge in combat-exposed veterans with and without posttraumatic stress disorder and normal controls.

The prolactin and cortisol responses to dexamethasone (0.5 mg) were studied in combat veterans with (n = 18) and without (n = 12) posttraumatic stress disorder (PTSD) and normal controls (n = 18). Both veteran groups demonstrated greater prolactin suppression than the normals. In contrast, only veterans with PTSD showed an enhanced cortisol suppression in response to dexamethasone. These findings suggest that the prolactin response to dexamethasone may reflect a feature of combat exposure rather than PTSD per se.

Diurnal neuroendocrine and autonomic function in acute and remitted depressed male patients.

This study evaluated diurnal data gathered hourly (1000 to 1800 hours) in males during acute depression and during remission of depression and in age-range/gender-matched normal controls. Mean, peak, variability, and time-course of the noradrenergic metabolite, plasma 3-methoxy, 4-hydroxyphenylglycol [MHPG]), plasma cortisol, and autonomic (mean arterial blood pressure [MAP] and heart rate) variables were examined. Compared to controls, acutely depressed, but not remitted depressed, patients had 1) an earlier plasma MHPG peak, 2) a greater intragroup variability of plasma MHPG, 3) a higher plasma cortisol concentration, 4) a lower MAP, and 5) tended to increase MAP more slowly than did the normal controls. The time course of diurnal heart rate also differed in acutely depressed patients from controls: acutely depressed patients started higher and converged by midday to normal levels. These diurnal data lend limited support to the dysregulation hypotheses of depression that suggest normal circadian rhythmicities are altered or disrupted in acute depression and that peripheral manifestations of central dysregulation normalize in remission of depression.