Faculty Bibliography

Background: Delineating the molecular basis of individual differences in the stress response is critical to understanding the pathophysiology of post-traumatic-stress-disorder (PTSD), with the ultimate goal of identifying biomarkers that can be associated with treatment response. Methods: We analyzed blood genome-wide expression, functional neuroendocrinology and immunology from a cross-sectional biomarker study with and without PTSD (n=68/group). In addition, gene expression in blood and brain (amygdala and hippocampus) and neuronal morphology were analyzed from a PTSD rat model, in which vulnerable and resilient phenotypes are identified according to the behavioral response to predator scent stress (PSS). Analyses of the human and animal data were performed separately, and then compared and integrated with the use of gene co-expression network analyses. Results: Differentially expressed (DE) genes were identified in association with PTSD. These DE genes were consistent with downregulation of glucocorticoid receptor (GR) signaling and upregulation of pro-inflammatory cytokine signaling. These findings were replicated by the DE-signatures identified in rat blood and brain, in association with exposure-related individual differences. Interestingly, even though the across-tissue overlap in rat DE-signatures was small at the individual gene level (6%), there was a high conservation at the upstream transcription factor level (36%) with GR and its signaling as the most convergent. Gene co-expression networks were also identified. Among the most promising networks, there was a large (>100 genes) PTSD co-expression module showing a high level of dysregulation (modular differential connectivity >50, compared to veterans without PTSD) and conservation in the blood and brain of PTSD-like rats. Functionally, this module is enriched with the genes related to innate immune response (p<0.001), and its eigengene expression associates with the lymphocyte lysozyme inhibition by dexamethasone (p<0.05) and plasma cortisol decline in the dexamethasone suppression test (p<0.001). Finally, GR-agonist administration in rats shortly after PSS prevented PTSD-like phenotypes by reversing the vulnerability-associated cytokine signaling in the amygdala and neuronal morphology patterns in the limbic brain. Conclusions: We identified genes, pathways and gene co-expression networks in the blood of combat veterans with PTSD. GR-dependent immune pathways and networks are associated with trauma-related individual differences in blood and brain, and can be the basis of treatment for PTSD

Major depressive disorder (MDD), common in the elderly, is a risk factor for dementia. Abnormalities in glutamatergic neurotransmission via the N-methyl-d-aspartate receptor (NMDA-R) have a key role in the pathophysiology of depression. This study examined whether depression was associated with cerebrospinal fluid (CSF) levels of NMDA-R neurotransmission-associated amino acids in cognitively intact elderly individuals with MDD and age- and gender-matched healthy controls. CSF was obtained from 47 volunteers (MDD group, N=28; age- and gender-matched comparison group, N=19) at baseline and 3-year follow-up (MDD group, N=19; comparison group, N=17). CSF levels of glutamine, glutamate, glycine, l-serine and d-serine were measured by high-performance liquid chromatography. CSF levels of amino acids did not differ across MDD and comparison groups. However, the ratio of glutamine to glutamate was significantly higher at baseline in subjects with MDD than in controls. The ratio decreased in individuals with MDD over the 3-year follow-up, and this decrease correlated with a decrease in the severity of depression. No correlations between absolute amino-acid levels and clinical variables were observed, nor were correlations between amino acids and other biomarkers (for example, amyloid-beta42, amyloid-beta40, and total and phosphorylated tau protein) detected. These results suggest that abnormalities in the glutamine-glutamate cycle in the communication between glia and neurons may have a role in the pathophysiology of depression in the elderly. Furthermore, the glutamine/glutamate ratio in CSF may be a state biomarker for depression.

INTRODUCTION: Psychiatric, physical and biological aspects of posttraumatic stress disorder (PTSD) may be associated with dysfunctions in several cellular processes including nitric oxide (NO) production. NO is synthesized from arginine in a reaction carried out by NO synthase (NOS) enzymes. The recently introduced "global arginine bioavailability ratio" (GABR; ratio of arginine to [ornithine+citrulline]) has been proposed as a reliable approximation of NO synthetic capacity in vivo. The objectives of the present study were to test the hypotheses that (i) subjects with combat-related PTSD have lower GABR scores than combat controls, (ii) GABR score is inversely associated with the severity of psychopathological measures, (iii) GABR score is inversely associated with markers of inflammation. METHODS: Metabolic profiling for plasma samples (i.e. arginine, citrulline and ornithine) and inflammation markers (interleukin [IL]-6, IL-1beta, tumor necrosis factor [TNF]-alpha, interferon [IFN]-gamma and C-reactive protein [CRP]) were assessed in 56 combat-exposed males with PTSD and 65 combat-exposed males without PTSD. We assessed severity of PTSD (Clinician Administered PTSD Scale [CAPS]) and depression (Beck Depression Inventory-II [BDI-II]) as well as history of early life trauma (Early Trauma Inventory [ETI]) and affectivity (Positive and Negative Affect Schedule [PANAS]). RESULTS: The GABR value was (i) significantly lower in PTSD subjects compared to controls (p=0.001), (ii) significantly inversely correlated with markers of inflammation including IL6 (p=0.04) and TNFalpha (p=0.02), and (iii) significantly inversely correlated with CAPS current (p=0.001) and lifetime (p<0.001) subscales, ETI (p=0.045) and PANAS negative (p=0.006). Adding antidepressant use or MDD diagnosis as covariates led to similar results. Adding age and BMI as covariates also led to similar results, with the exception of IL6 and ETI losing their significant association with GABR. DISCUSSION: This study provides the first evidence that global arginine bioavailability, a marker of NO synthetic capacity in vivo, is lower in veterans with PTSD and is negatively associated with some markers of inflammation as well as with measures of PTSD symptom severity, negative affectivity and childhood adverse experiences. These findings add to the accumulating evidence that specific cellular dysfunction may be associated with the symptomatology of PTSD and may help to explain the higher burden of cardio-metabolic disturbances seen in this disorder.

OBJECTIVE: The primary goal of this analysis was to assess whether recent use of outpatient services for general medical concerns by Vietnam veterans varies according to level of posttraumatic stress disorder (PTSD) symptomatology over time. Another goal was to determine whether PTSD symptomatology was associated with veterans' reports of discussing behavioral health issues as part of a general medical visit. METHODS: Self-reported service use data and measures of PTSD were from a nationally representative sample of 848 male and female Vietnam theater veterans (individuals who were deployed to the Vietnam theater of operations) who participated in the National Vietnam Veterans Longitudinal Study, a 25-year follow-up of a cohort of veterans originally interviewed from 1984-1988 as part of the National Vietnam Veterans Readjustment Study. Four categories of PTSD symptomatology course over 25 years were defined, and logistic regression models were used to assess their relationship with recent use of outpatient general medical services. RESULTS: Male and female theater veterans with high or increasing PTSD symptomatology over the period were more likely than those with low symptomatology to report recent VA outpatient visits. Males in the increasing and high categories were also more likely to discuss behavioral health issues at general medical visits. CONCLUSIONS: Vietnam veterans with high and increasing PTSD symptomatology over time were likely to use VA outpatient general health services. Attention to stressors of the aging process and to persistence of PTSD symptoms is important for Vietnam veterans, as is addressing PTSD with other psychiatric and medical comorbidities within the context of outpatient general medical care.

BACKGROUND: Several psychiatric disorders may be characterized by peripheral telomere shortening. However, it is unclear whether telomere shortening is associated with these psychiatric disorders per se or, rather, with underlying dimensional parameters that are often, but not necessarily, associated with them. We explored the association between dimensional psychopathological measures and telomere length (TL) in granulocytes among veterans independent of psychiatric diagnosis. METHODS: Seventy-six combat-exposed male veterans (41 psychiatrically healthy, 18 with Posttraumatic Stress Disorder [PTSD] and 17 with concomitant PTSD and Major Depressive Disorder [MDD]) had TL assayed. Assessments included Clinician-Administered PTSD Scale (CAPS), Beck Depression Inventory-II (BDI-II), Early Trauma Inventory (ETI), Symptom Checklist-90-R Global Severity Index (SCL-90-GSI), Perceived Stress Scale (PSS) and Positive and Negative Affect Schedule (PANAS). Correlations were corrected for age, BMI, antidepressants and ethnicity. RESULTS: Across subjects, TL was negatively correlated with early trauma (p<0.001), global psychopathological severity (p=0.044) and perceived stress (p=0.019), positively correlated with positive affect (p=0.026), not significantly correlated with symptom severity of PTSD, depression or negative affect. Across these dimensions, early trauma and positive affect were associated with TL after excluding subjects with somatic illnesses. LIMITATIONS: The study was cross-sectional with a moderate sample size and only male combat-exposed subjects. CONCLUSIONS: These preliminary findings suggest that early trauma, severity of perceived stress and general psychopathological symptoms are more closely associated with shorter TL than is the severity of core diagnostic symptoms of PTSD or MDD, whereas positive affect is associated with longer TL. Larger-scale studies should assess TL associated with specific psychiatric dimensions, apart from only categorical psychiatric diagnoses, to develop more specific biologically-relevant endophenotypes.

Posttraumatic stress symptoms are associated with poorer social and occupational functioning and quality of life. However, general assessments of functioning do not determine the extent to which these difficulties are directly related to PTSD symptoms. This study examines the psychometric properties of a self-report measure, the 27-item Posttraumatic Stress Related Functioning Inventory (PRFI), which was developed to provide a self-report tool for clinicians and researchers to better understand the perceived impact of PTSD symptoms on functioning. The psychometric properties of the PRFI were examined utilizing data collected within a larger study examining quality of life and functioning in 251 veterans who had served in OEF/OIF/OND and endorsed the presence of subsyndromal or greater levels of PTSD symptoms at screening. One-year test-retest reliability of the measure was examined in a subset of the baseline sample who received a second administration of the PRFI (n = 109). Higher levels of PTSD symptoms were associated with poorer functioning in all domains. The PRFI demonstrated convergent validity with a measure of PTSD symptoms and was less correlated with measures of alcohol and drug use, good internal consistency and test-retest reliability from baseline to one-year follow-up. The PRFI provides self-report information regarding several domains of functioning. This initial examination of psychometric properties of the scale indicated that it may be useful for efficiently eliciting information about the ways in which PTSD symptoms in veterans impact everyday functioning.

Sexual dysfunction is not a symptom of PTSD but is a common clinical complaint in trauma survivors with this disorder. In that there are biological parallels in the neuroendocrine processes underlying both PTSD and sexual behavior, we conducted an exploratory investigation of the relationship of PTSD and related neuroendocrine indicators with sexual dysfunction in armed service veterans. Major Depressive Disorder, highly comorbid with PTSD and sexual dysfunction, was also assessed. In veterans with PTSD, sexual problems were associated with plasma DHEA and cortisol, urinary catecholamines, and glucocorticoid sensitivity, even when controlling for the effects of comorbid depression. In a subsample analysis, testosterone levels did not distinguish PTSD or sexual dysfunction, suggesting that sexual problems reported by veterans in this sample were not the result of organic disorder. PTSD did predict higher dihydrotestosterone (DHT) levels, which were associated with sexual problems. More detailed assessment of sexual dysfunction in biologically informed studies of PTSD is warranted to clarify the relationships of PTSD symptomatology and related neurobiology with sexual dysfunction.

INTRODUCTION: Mitochondrial abnormalities may be involved in PTSD, although few studies have examined this. Mitochondrial DNA copy number (mtDNAcn) in blood cells is an emerging systemic index of mitochondrial biogenesis and function. The present study assessed mtDNAcn in male combat-exposed veterans with PTSD compared to those without PTSD as well as its correlation with clinical scales. METHODS: mtDNAcn was assessed with a TaqMan multiplex assay in granulocytes of 43 male combat veterans with (n=43) or without (n=44) PTSD. Twenty of the PTSD subjects had co-morbid major depressive disorder (MDD). The Clinician Administered PTSD Scale (CAPS), the Positive and Negative Affect Schedule (PANAS), the Early Trauma Inventory (ETI) and the Beck Depression Inventory II (BDI-II) were used for the clinical assessments. All analyses were corrected for age and BMI. RESULTS: mtDNAcn was significantly lower in subjects with PTSD (p<0.05). Within the PTSD group, those with moderate PTSD symptom severity had relatively higher mtDNAcn than those with mild or severe symptoms (p<0.01). Within the PTSD group, mtDNAcn was positively correlated with PANAS positive subscale ratings (p<0.01) but was not significantly correlated with PANAS negative subscale, ETI or BDI-II ratings. DISCUSSION: This study provides the first evidence of: (i) a significant decrease of mtDNAcn in combat PTSD, (ii) a possible "inverted-U" shaped relationship between PTSD symptom severity and mtDNAcn within PTSD subjects, and (iii) a direct correlation of mtDNAcn with positive affectivity within PTSD subjects. Altered mtDNAcn in PTSD may reflect impaired energy metabolism, which might represent a novel aspect of its pathophysiology.

Background: Circulating hematopoietic progenitor cells (PCs; CD34+ and CD34+/KDR+) facilitate neurogenesis and neovascularization, promoting increased cortical thickness and white matter integrity in animal models. However, it unknown whether low PCs are associated with trauma symptoms or neurovas-cular health among veterans. Objectives: Determine whether lower PCs are associated with: (1) posttraumatic stress disorder (PTSD) diagnosis, duration and symptoms, (2) decreased prefrontal cortical (PFC) thickness, and (3) reduced white matter integrity, indexed by white matter hypointen-sities (WMH), and tracts relevant to fear processing: the Uncinate Fasciculus (UF) and Inferior Fronto-Occipital Fasciculus (IFOF). Methods: 100 male and 8 female combat-exposed veterans reported PTSD symptoms (43 PTSD+) and were studied by 3T MRI, acquiring whole brain T1-weighted images and, for a subsample (n = 54), diffusion tensor images. PCs were characterized by flow cytometry. Results: Higher CD34+/KDR+ counts were related to greater PFC thickness (DM-PFC and DL-PFC), while higher CD34+ counts were related to better IFOF (but not UF) integrity and fewer WMH, controlling for age, gender, smoking, cardiovascular comorbidities and head injury. In PTSD+ subjects, CD34+/KDR+ counts were inversely related to time since the worst trauma, but not PTSD diagnosis or current symptoms. Conclusions: PCs are associated with enhanced white matter integrity and PFC thickness, with potential implications for neurovascular plasticity and fear processing. In patients with PTSD, PCs may exhibit accelerated depletion with increasing time post-trauma

Because Vietnam veterans comprise the majority of all living veterans and most are now older adults, the urgency and potential value of studying the long-term health effects of service in the Vietnam War, including effects on mortality, is increasing. The present study is the first prospective mortality assessment of a representative sample of Vietnam veterans. We used one of the longest follow-up periods to date (spanning older adulthood) and conducted one of the most comprehensive assessments of potential risk factors. Vital status and cause of death were ascertained for the 1,632 veterans who fought in the Vietnam theater (hereafter referred to as theater veterans) and for 716 Vietnam War-era veterans (hereafter referred to as era veterans) who participated in the National Vietnam Veterans Readjustment Study (1987-2011). As of April 2011, 16.0% (95% confidence interval: 13.1, 19.0) of all Vietnam veterans who were alive in the 1980s were deceased. Male theater veterans with a high probability of posttraumatic stress disorder (PTSD) were nearly 2 times more likely to have died than were those without PTSD, even after adjustment for sociodemographic and other characteristics. A high level of exposure to war zone stress was independently associated with mortality for both male and female theater veterans after adjustment for sociodemographic characteristics, PTSD, and physical comorbid conditions. Theater veterans with a high level of exposure to war zone stress and a high probability of PTSD had the greatest mortality risk (adjusted hazard ratio = 2.34, 95% confidence interval: 1.24, 4.43).