COMT Val158Met polymorphism moderates the association between PTSD symptom severity and hippocampal volume

BACKGROUND

Memory-based alterations are among the hallmark symptoms of posttraumatic stress disorder (PTSD) and may be associated with the integrity of the hippocampus. However, neuroimaging studies of hippocampal volume in individuals with PTSD have yielded inconsistent results, raising the possibility that various moderators, such as genetic factors, may influence this association. We examined whether the catechol-O-methyltransferase (COMT) Val158Met polymorphism, which has previously been shown to be associated with hippocampal volume in healthy individuals, moderates the association between PTSD and hippocampal volume.

METHODS

Recent war veterans underwent structural MRI on a 3 T scanner. We extracted volumes of the right and left hippocampus using FreeSurfer and adjusted them for individual differences in intracranial volume. We assessed PTSD severity using the Clinician-Administered PTSD Scale. Hierarchical linear regression was used to model the genotype (Val158Met polymorphism) × PTSD severity interaction and its association with hippocampal volume.

RESULTS

We included 146 white, non-Hispanic recent war veterans (90% male, 53% with diagnosed PTSD) in our analyses. A significant genotype × PTSD symptom severity interaction emerged such that individuals with greater current PTSD symptom severity who were homozygous for the Val allele showed significant reductions in left hippocampal volume.

LIMITATIONS

The direction of proposed effects is unknown, thus precluding definitive assessment of whether differences in hippocampal volume reflect a consequence of PTSD, a pre-existing characteristic, or both.

CONCLUSION

Our findings suggest that the COMT polymorphism moderates the association between PTSD and hippocampal volume. These results highlight the role that the dopaminergic system has in brain structure and suggest a possible mechanism for memory disturbance in individuals with PTSD.

Investigation of bidirectional longitudinal associations between advanced epigenetic age and peripheral biomarkers of inflammation and metabolic syndrome

Epigenetic age estimations based on DNA methylation (DNAm) can predict human chronological age with a high level of accuracy. These DNAm age algorithms can also be used to index advanced cellular age, when estimated DNAm age exceeds chronological age. Advanced DNAm age has been associated with several diseases and metabolic and inflammatory pathology, but the causal direction of this association is unclear. The goal of this study was to examine potential bidirectional associations between advanced epigenetic age and metabolic and inflammatory markers over time in a longitudinal cohort of 179 veterans with a high prevalence of posttraumatic stress disorder (PTSD) who were assessed over the course of two years. Analyses focused on two commonly investigated metrics of advanced DNAm age derived from the Horvath (developed across multiple tissue types) and Hannum (developed in whole blood) DNAm age algorithms. Results of cross-lagged panel models revealed that advanced Hannum DNAm age at Time 1 (T1) was associated with increased (i.e., accounting for T1 levels) metabolic syndrome (MetS) severity at Time 2 (T2; p = < 0.001). This association was specific to worsening lipid panels and indicators of abdominal obesity (p = 0.001). In contrast, no baseline measures of inflammation or metabolic pathology were associated with changes in advanced epigenetic age over time. No associations emerged between advanced Horvath DNAm age and any of the examined biological parameters. Results suggest that advanced epigenetic age, when measured using an algorithm developed in whole blood, may be a prognostic marker of pathological metabolic processes. This carries implications for understanding pathways linking advanced epigenetic age to morbidity and mortality.

Conceptualizing traumatic stress and the structure of posttraumatic psychopathology through the lenses of RDoC and HiTOP

Trauma-related psychopathology, most notably posttraumatic stress disorder (PTSD), poses unique challenges for psychiatric nosology due to the wide range of symptoms and diagnoses associated with trauma and challenges representing the impact of trauma exposure on psychopathology. In this paper, we review the literature on categorical (i.e., Diagnostic and Statistical Manual of Mental Disorders and International Classification of Diseases systems) versus dimensional conceptualizations of trauma-related symptoms with an emphasis on the Research Domain Criteria (RDoC) and the Hierarchical Taxonomy of Psychopathology (HiTOP) frameworks. We identify strengths of each approach and challenges in accommodating the full range of trauma-related psychopathology and the clinical implications thereof. We discuss several potential approaches for improving the representation of traumatic stress, including the use of PTSD subtypes, trauma-related specifiers for psychiatric diagnoses, and the development of a dimension that we call the traumatic stress spectrum, which spans both adaptive and adverse reactions to trauma. These approaches to representing traumatic stress can be evaluated empirically and further refined. We also discuss how the use of an integrated RDoC-HiTOP approach to reconceptualize traumatic stress might maximize the ability to model valid and reliable trauma-related phenotypes, which would aid in the investigation of clinically relevant biological correlates.

Latent class analysis of personality disorders in adults with posttraumatic stress disorder: results from the National Epidemiologic Survey on Alcohol and Related Conditions

OBJECTIVE

To characterize predominant typologies of co-occurring personality disorders among adults with posttraumatic stress disorder (PTSD) and examine their relation to Axis I comorbidities, health-related quality of life, and course and treatment of PTSD.

METHOD

Latent class analysis was conducted on the 10 DSM-IV personality disorders in a nationally representative sample of 2,463 adults with a lifetime diagnosis of PTSD from Wave 2 (2004-2005) of the National Epidemiologic Survey on Alcohol and Related Conditions.

RESULTS

Three latent classes of personality disorders were identified: a borderline-dysregulated class (11.4%), an obsessive-paranoid class (13.1%), and a no/low personality disorders class (75.5%). The borderline-dysregulated and obsessive-paranoid classes were more likely than the no/low personality disorder class to have a broad range of comorbid Axis I diagnoses and to have ever attempted suicide (ORs = 1.50-8.01), and they reported lower mental health-related quality of life. The borderline-dysregulated class was less likely than the no/low personality disorder class to have experienced remission of their most recent episode of PTSD (OR = 0.54; 95% CI, 0.38-0.75) and was more likely to have been prescribed medication for PTSD (OR = 1.65; 95% CI, 1.20-2.28) and to have used alcohol and drugs to mitigate their PTSD symptoms (OR = 2.77; 95% CI, 1.62-4.74). The obsessive-paranoid class was more likely than the no/low personality disorders class to report sexual assault as their worst trauma (OR = 2.22; 95% CI, 1.36-3.61) and had an earlier age at onset of PTSD symptoms compared to the other 2 classes.

CONCLUSIONS

Among US adults with PTSD, the 10 DSM-IV personality disorders can be classified into 3 "person-based" typologies, which are differentially associated with comorbid Axis I disorders, mental health-related quality of life, and clinical and treatment characteristics of this disorder. These results suggest that comprehensive assessment of personality disorders may help inform etiologic models and treatment approaches for PTSD.

PTSD is associated with increased DNA methylation across regions of HLA-DPB1 and SPATC1L

Posttraumatic stress disorder (PTSD) is characterized by intrusive thoughts, avoidance, negative alterations in cognitions and mood, and arousal symptoms that adversely affect mental and physical health. Recent evidence links changes in DNA methylation of CpG cites to PTSD. Since clusters of proximal CpGs share similar methylation signatures, identification of PTSD-associated differentially methylated regions (DMRs) may elucidate the pathways defining differential risk and resilience of PTSD. Here we aimed to identify epigenetic differences associated with PTSD. DNA methylation data profiled from blood samples using the MethylationEPIC BeadChip were used to perform a DMR analysis in 187 PTSD cases and 367 trauma-exposed controls from the Grady Trauma Project (GTP). DMRs were assessed with R package bumphunter. We identified two regions that associate with PTSD after multiple test correction. These regions were in the gene body of HLA-DPB1 and in the promoter of SPATC1L. The DMR in HLA-DPB1 was associated with PTSD in an independent cohort. Both DMRs included CpGs whose methylation associated with nearby sequence variation (meQTL) and that associated with expression of their respective genes (eQTM). This study supports an emerging literature linking PTSD risk to genetic and epigenetic variation in the HLA region.

A comparison of ICD-11 and DSM criteria for posttraumatic stress disorder in two national samples of U.S. military veterans

BACKGROUND

The proposed ICD-11 criteria for posttraumatic stress disorder (PTSD) differ substantially from the DSM-5. ICD-11 eliminated several PTSD symptoms thought to be nonspecific, with the goal of reducing psychiatric comorbidities. However, this change also results in a narrower PTSD definition that may fail to capture individuals with clinically significant PTSD. The purpose of the current study was to compare prevalence and psychiatric comorbidities of DSM (IV/5) and ICD-11 PTSD.

METHODS

We evaluated concordance between DSM (IV/5) and ICD-11 PTSD diagnoses in a web survey of two nationally representative samples of U.S. military veterans (ns = 3517 and 1484). Lifetime and past-month PTSD symptoms were assessed with the DSM-IV-based PTSD Checklist-Specific Stressor version and the DSM-5-based PTSD Checklist-5. Psychiatric comorbidities were assessed using MINI Neuropsychiatric Interview modules.

RESULTS

A significantly greater proportion of veterans met criteria for lifetime and past-month PTSD under DSM-IV/5 than under ICD-11. 21.8-35.9% of those who met criteria under DSM IV/5 did not meet under ICD-11, whereas only 2.4-7.1% of those who met under ICD-11 did not meet under DSM-IV/5. Psychiatric comorbidities did not significantly differ between DSM-IV/5 and ICD-11.

LIMITATIONS

This study relied upon self-report measures of PTSD, distress/impairment, and psychiatric comorbidities.

CONCLUSIONS

The proposed ICD-11 criteria identify fewer PTSD cases than DSM-IV/5 without reducing psychiatric comorbidities. Veterans with clinically significant PTSD symptoms may not meet ICD-11 PTSD criteria, possibly affecting eligibility for healthcare, disability, and other services. The ICD-11 criteria could be revised to capture more PTSD cases before ICD-11 is published in 2018.

Perspectives on the conceptualization of the dissociative subtype of PTSD and implications for treatment

A dissociative subtype of PTSD was added to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to denote a distinct presentation of PTSD marked by symptoms of derealization and depersonalization. The subtype has brought renewed interest in the conceptualization of dissociation in PTSD, and raised questions about its treatment. We review the evidence for two models of PTSD-related dissociative symptoms and the treatment approaches that align with each. We find support for the contributions of biologically-based trait-level factors to dissociation, and suggest that empirically supported treatments for PTSD demonstrate efficacy for patients with the subtype.

Single-Nucleus Transcriptome Profiling of Dorsolateral Prefrontal Cortex: Mechanistic Roles for Neuronal Gene Expression, Including the 17q21.31 Locus, in PTSD Stress Response

OBJECTIVE

Multidisciplinary studies of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) implicate the dorsolateral prefrontal cortex (DLPFC) in disease risk and pathophysiology. Postmortem brain studies have relied on bulk-tissue RNA sequencing (RNA-seq), but single-cell RNA-seq is needed to dissect cell-type-specific mechanisms. The authors conducted the first single-nucleus RNA-seq postmortem brain study in PTSD to elucidate disease transcriptomic pathology with cell-type-specific resolution.

METHOD

Profiling of 32 DLPFC samples from 11 individuals with PTSD, 10 with MDD, and 11 control subjects was conducted (∼415K nuclei; >13K cells per sample). A replication sample included 15 DLPFC samples (∼160K nuclei; >11K cells per sample).

RESULTS

Differential gene expression analyses identified significant single-nucleus RNA-seq differentially expressed genes (snDEGs) in excitatory (EX) and inhibitory (IN) neurons and astrocytes, but not in other cell types or bulk tissue. MDD samples had more false discovery rate-corrected significant snDEGs, and PTSD samples had a greater replication rate. In EX and IN neurons, biological pathways that were differentially enriched in PTSD compared with MDD included glucocorticoid signaling. Furthermore, glucocorticoid signaling in induced pluripotent stem cell (iPSC)-derived cortical neurons demonstrated greater relevance in PTSD and opposite direction of regulation compared with MDD, especially in EX neurons. Many snDEGs were from the 17q21.31 locus and are particularly interesting given causal roles in disease pathogenesis and DLPFC-based neuroimaging (PTSD: ARL17B, LINC02210-CRHR1, and LRRC37A2; MDD: LRRC37A and LRP4), while others were regulated by glucocorticoids in iPSC-derived neurons (PTSD: SLC16A6, TAF1C; MDD: CDH3).

CONCLUSIONS

The study findings point to cell-type-specific mechanisms of brain stress response in PTSD and MDD, highlighting the importance of examining cell-type-specific gene expression and indicating promising novel biomarkers and therapeutic targets.

Klotho, PTSD, and advanced epigenetic age in cortical tissue

This study examined the klotho (KL) longevity gene polymorphism rs9315202 and psychopathology, including posttraumatic stress disorder (PTSD), depression, and alcohol-use disorders, in association with advanced epigenetic age in three postmortem cortical tissue regions: dorsolateral and ventromedial prefrontal cortices and motor cortex. Using data from the VA National PTSD Brain Bank (n = 117), we found that rs9315202 interacted with PTSD to predict advanced epigenetic age in motor cortex among the subset of relatively older (>=45 years), white non-Hispanic decedents (corrected p = 0.014, n = 42). An evaluation of 211 additional common KL variants revealed that only variants in linkage disequilibrium with rs9315202 showed similarly high levels of significance. Alcohol abuse was nominally associated with advanced epigenetic age in motor cortex (p = 0.039, n = 114). The rs9315202 SNP interacted with PTSD to predict decreased KL expression via DNAm age residuals in motor cortex among older white non-Hispanics decedents (indirect β = -0.198, p = 0.027). Finally, in dual-luciferase enhancer reporter system experiments, we found that inserting the minor allele of rs9315202 in a human kidney cell line HK-2 genomic DNA resulted in a change in KL transcriptional activities, likely operating via long noncoding RNA in this region. This was the first study to examine multiple forms of psychopathology in association with advanced DNA methylation age across several brain regions, to extend work concerning the association between rs9315202 and advanced epigenetic to brain tissue, and to identify the effects of rs9315202 on KL gene expression. KL augmentation holds promise as a therapeutic intervention to slow the pace of cellular aging, disease onset, and neuropathology, particularly in older, stressed populations.

Cerebral perfusion is associated with blast exposure in military personnel without moderate or severe TBI

Due to the use of improvised explosive devices, blast exposure and mild traumatic brain injury (mTBI) have become hallmark injuries of the Iraq and Afghanistan wars. Although the mechanisms of the effects of blast on human neurobiology remain active areas of investigation, research suggests that the cerebrovasculature may be particularly vulnerable to blast via molecular processes that impact cerebral blood flow. Given that recent work suggests that blast exposure, even without a subsequent TBI, may have negative consequences on brain structure and function, the current study sought to further understand the effects of blast exposure on perfusion. One hundred and eighty military personnel underwent pseudo-continuous arterial spin labeling (pCASL) imaging and completed diagnostic and clinical interviews. Whole-brain analyses revealed that with an increasing number of total blast exposures, there was significantly increased perfusion in the right middle/superior frontal gyri, supramarginal gyrus, lateral occipital cortex, and posterior cingulate cortex as well as bilateral anterior cingulate cortex, insulae, middle/superior temporal gyri and occipital poles. Examination of other neurotrauma and clinical variables such as close-range blast exposures, mTBI, and PTSD yielded no significant effects. These results raise the possibility that perfusion may be an important neural marker of brain health in blast exposure.

Stress-Generative Effects of Posttraumatic Stress Disorder: Transactional Associations Between Posttraumatic Stress Disorder and Stressful Life Events in a Longitudinal Sample

Longitudinal studies have demonstrated transactional associations between psychopathology and stressful life events (SLEs), such that psychopathology predicts the occurrence of new SLEs, and SLEs in turn predict increasing symptom severity. The association between posttraumatic stress disorder (PTSD), specifically, and stress generation remains unclear. This study used temporally sequenced data from 116 veterans (87.9% male) to examine whether PTSD symptoms predicted new onset SLEs, and if these SLEs were associated with subsequent PTSD severity. The SLEs were objectively rated, using a clinician-administered interview and consensus-rating approach, to assess the severity, frequency, and personal dependence (i.e., if the event was due to factors that were independent of or dependent on the individual) of new-onset SLEs. A series of mediation models were tested, and results provided evidence for moderated mediation whereby baseline PTSD severity robustly predicted personally dependent SLEs, B = 0.03, p = .006, and dependent SLEs predicted increases in follow-up PTSD symptom severity, B = -0.04, p = .003, among participants with relatively lower baseline PTSD severity. After we controlled for baseline PTSD severity, personality traits marked by low constraint (i.e., high impulsivity) were also associated with an increased number of dependent SLEs. Our results provide evidence for a stress-generative role of PTSD and highlight the importance of developing interventions aimed at reducing the occurrence of personally dependent stressors.

Intermittent explosive disorder: associations with PTSD and other Axis I disorders in a US military veteran sample

This study examined the prevalence of intermittent explosive disorder (IED) and its associations with trauma exposure, posttraumatic stress disorder (PTSD), and other psychiatric diagnoses in a sample of trauma-exposed veterans (n=232) with a high prevalence of PTSD. Structural associations between IED and latent dimensions of internalizing and externalizing psychopathology were also modeled to examine the location of IED within this influential structure. Twenty-four percent of the sample met criteria for a lifetime IED diagnosis and those with the diagnosis were more likely to meet criteria for lifetime PTSD than those without (30.3% vs. 14.3% respectively). Furthermore, regression analyses revealed lifetime PTSD severity to be a significant predictor of IED severity after controlling for combat, trauma exposure, and age. Finally, confirmatory factor analysis revealed significant cross-loadings of IED on both the externalizing and distress dimensions of psychopathology, suggesting that the association between IED and other psychiatric disorders may reflect underlying tendencies toward impulsivity and aggression and generalized distress and negative emotionality, respectively.

Polygenic Risk for Externalizing Psychopathology and Executive Dysfunction in Trauma-Exposed Veterans

The frequent co-occurrence of antisocial behavior and other disinhibited phenotypes reflects a highly heritable externalizing spectrum. We examined the molecular genetic basis of this spectrum by testing polygenic associations with psychopathology symptoms, impulsive traits, and cognitive functions in two samples of primarily military veterans (n =537, n =194). We also investigated whether polygenic risk for externalizing moderated the effects of trauma on these phenotypes. As hypothesized, polygenic risk positively predicted externalizing psychopathology and negatively predicted performance on inhibitory control tasks. Gene-by-environment effects were also evident, with trauma exposure predicting greater impulsivity and less working memory capacity, but only at high levels of genetic liability. As expected, polygenic risk was not associated with internalizing psychopathology or episodic memory performance. This is the first independent replication of the polygenic score as a measure of genetic predispositions for externalizing and provides preliminary evidence that executive dysfunction is a heritable vulnerability for externalizing psychopathology.

Longitudinal Associations between Posttraumatic Stress Disorder Severity and Personality Disorder Features among Female Rape Survivors

This study evaluated how change in posttraumatic stress disorder (PTSD) symptoms was associated with residualized change in comorbid personality disorder (PD) features and vice versa over the course of 5-10 years. The sample was comprised of 79 female rape survivors who met criteria for PTSD and who were a part of a larger study examining the effects of trauma-focused therapy. PTSD was assessed with the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) version of the Clinician-Administered PTSD Scale [CAPS-IV (1)] and PD features were assessed with the DSM-IV dimensional PD scales on the Schedule for Non-adaptive and Adaptive Personality [SNAP (2)]. PTSD symptom severity and PD features were assessed at baseline and between 5 and 10 years after completing treatment. Multiple regression analyses revealed that PTSD symptom change was related to residualized change in PD severity for paranoid, schizotypal, antisocial, borderline, avoidant, and dependent PD (βs ranged from -0.23 to -0.33; all ps < 0.05). In addition, for borderline and antisocial PDs, longitudinal stability of the PD was attenuated among those with greater PTSD symptom improvement (i.e., the relationship between these PDs over time was altered as a function of PTSD symptom change; βs ranged from -0.27 to -0.29; all ps < 0.05). Similarly, change in severity of paranoid, schizotypal, antisocial, avoidant, and obsessive-compulsive (OC) PD was associated with residualized change in PTSD symptoms (βs ranged from -0.32 to -0.41; all ps < 0.05), and the longitudinal stability of PTSD was attenuated as a product of change in OC PD (β = -0.27; p < 0.02). These findings suggest that these two sets of disorders may impact one another substantially, altering the course of even chronic, characterological conditions. This carries important clinical implications for the treatment of both PTSD and PDs.

Psychological effects of the marathon bombing on Boston-area veterans with posttraumatic stress disorder

This study examined the psychological impact of the Boston Marathon bombing using data from an ongoing longitudinal study of Boston-area veterans with posttraumatic stress disorder (PTSD; N = 71). Participants were assessed by telephone within 1 week of the end of the event; 42.3% of participants reported being personally affected by the bombings and/or the manhunt that followed. The majority of them reported that the bombing reminded them of their own traumas and/or caused other emotional distress. Examination of change in posttraumatic stress disorder (PTSD) symptoms from a prebombing assessment an average of 2 months earlier to 1 week after the event revealed no significant change in symptoms across the sample as a whole. However, examination of patterns of change at the individual level revealed significant correlations (r = .33; p = .005) between distress at the time of the event and change in total PTSD symptom severity, with this effect accounted for primarily by increases in intrusion and avoidance symptoms (rs = .35 and .31, ps = .002 and .008, respectively). Findings of this study should raise awareness of the potential impact of terror attacks, mass shootings, and other events of this type on the well-being of individuals with histories of trauma and/or pre-existing PTSD.

Close-Range Blast Exposure Is Associated with Altered White Matter Integrity in Apolipoprotein ɛ4 Carriers

Evidence suggests that blast exposure has profound negative consequences for the health of the human brain, and that it may confer risk for the development of neurodegenerative diseases such as chronic traumatic encephalopathy and Alzheimer's disease (AD). Although the molecular mechanisms linking blast exposure to subsequent neurodegeneration is an active focus of research, recent studies suggest that genetic risk for AD may elevate the risk of neurodegeneration following traumatic brain injury (TBI). However, it is currently unknown if blast exposure also interacts with AD risk to promote neurodegeneration. In this study we examined whether apolipoprotein (APOE) ɛ4, a well-known genetic risk factor for AD, influenced the relationship between blast exposure and white matter integrity in a cohort of 200 Iraq and Afghanistan war veterans. Analyses revealed a significant interaction between close-range blast exposure (CBE) (close range being within 10 m) and APOE ɛ4 carrier status in predicting white matter abnormalities, measured by a voxelwise cluster-based method that captures spatial heterogeneity in white matter disruptions. This interaction remained significant after controlling for TBI, pointing to the specificity of CBE and APOE in white matter disruptions. Further, among veteran ɛ4 carriers exposed to close-range blast, we observed a positive association between the number of CBEs and the number of white matter abnormalities. These results raise the possibility that CBE interacts with AD genetic influences on neuropathological processes such as the degradation of white matter integrity.

PTSD and the klotho longevity gene: Evaluation of longitudinal effects on inflammation via DNA methylation

BACKGROUND

Longevity gene klotho (KL) is associated with age-related phenotypes including lifespan, cardiometabolic disorders, cognition, and brain morphology, in part, by conferring protection against inflammation. We hypothesized that the KL/inflammation association might be altered in the presence of psychiatric stress and operate via epigenetic pathways. We examined KL polymorphisms, and their interaction with posttraumatic stress disorder (PTSD) symptoms, in association with KL DNA methylation in blood. We further examined KL DNA methylation as a predictor of longitudinal changes in a peripheral biomarker of inflammation (C-reactive protein; CRP).

METHODS

The sample comprised 309 white non-Hispanic military veterans (93.5 % male; mean age: 32 years, range: 19-65; 30 % PTSD per structured diagnostic interview); 111 were reassessed approximately two years later.

RESULTS

Analyses revealed a methylation quantitative trait locus at rs9527025 (C370S, previously implicated in numerous studies of aging) in association with a Cytosine-phosphate-Guanine site (cg00129557; B = -.65, p =  1.29 X 10^-20), located within a DNase hypersensitivity site in the body of KL. There was also a rs9527025 x PTSD severity interaction (B = .004, p = .035) on methylation at this locus such that the minor allele was associated with reduced cg00129557 methylation in individuals with few or no PTSD symptoms while this effect was attenuated in those with elevated levels of PTSD. Path models revealed that methylation at cg00129557 was inversely associated with CRP over time (B = -.14, p = .005), controlling for baseline CRP. There was also an indirect effect of rs9527025 X PTSD on subsequent CRP via cg00129557 methylation (indirect B = -.002, p = .033).

CONCLUSIONS

Results contribute to our understanding of the epigenetic correlates of inflammation in PTSD and suggest that KL methylation may be a mechanism by which KL genotype confers risk vs. resilience to accelerated aging in those experiencing traumatic stress.

Optimization of in vivo tumor targeting in SCID mice with divalent forms of 741F8 anti-c-erbB-2 single-chain Fv: effects of dose escalation and repeated i.v. administration

Single-chain Fv molecules in monovalent (sFv) and divalent [(sFv')2] forms exhibit highly specific tumor targeting in mice as a result of their small size and rapid systemic clearance. As a consequence, there is a rapid reversal of the sFv blood/tumor gradient, resulting in diminished retention of sFv species in tumors. In this report we investigate two distinct strategies, dose escalation and repetitive intravenous (i.v.) dosing, aiming to increase the absolute selective retention of radiolabeled anti-c-erbB-2 125I-741F8 (sFv')2 in c-erbB-2-overexpressing SK-OV-3 tumors in mice with severe combined immunodeficiency (SCID). A dose-escalation strategy was applied to single i.v. injections of 125I-741F8 (sFv')2. Doses from 50 micrograms to 1000 micrograms were administered without a significant decrease in tumor targeting or specificity. High doses resulted in large increases in the absolute retention of 125I-741F8 (sFv')2. For example, raising the administered dose from 50 micrograms to 1000 micrograms increased the tumor retention 24 h after injection from 0.46 microgram/g to 9.5 micrograms/g, and resulted in a net increase of greater than 9 micrograms/g. Over the same dose range, the liver retention rose from 0.06 microgram/g to 1 microgram/g, and resulted in a net increase of less than 1 microgram/g. The retention of 9.5 micrograms/g in tumor 24 h following the 1000-micrograms dose of (sFv')2 was comparable to that seen 24 h after a 50-micrograms dose of 125I-741F8 IgG, indicating that the use of large doses of (sFv')2 may partially offset their rapid clearance. When two doses were administered by i.v. injection 24 h apart, the specificity of delivery to tumor observed after the first dose was maintained following the second injection. Tumor retention of 125I-741F8 (sFv')2 was 0.32 microgram/g at 24 h and 0.22 micrograms/g at 48 h following a single injection of 20 micrograms, while 0.04 microgram/ml and 0.03 microgram/ml were retained in blood at the same assay times. After a second 20-micrograms injection at the 24-h assay time, tumor retention increased to 0.49 micrograms/g, and blood retention was 0.06 microgram/ml, at the 48-h point. These results suggest that multiple high-dose administrations of radiolabeled 741F8 (sFv')2 may lead to the selective tumor localization of therapeutic radiation doses.

Risk of eye splash in obstetric procedures

A prospective cross-sectional study was designed to determine the rates of upper facial splash during obstetric deliveries. Macroscopic splashes on the attached eye shields of surgical masks, worn for obstetric deliveries were enumerated for a sample of parturients during a 3-month period. Masks were collected for 68 vaginal and 44 cesarean deliveries, 31% of all deliveries during the study period. For cesarean deliveries, 68% (30) of all masks worn by primary surgeons had at least one splash; 57% (17) of which were heavily contaminated (more than five splashes). For the first assistant, 68% (30) of all masks had at least one splash; 23% (7) of which were heavily contaminated. During vaginal deliveries 44% (30) of masks worn by the delivering physician had at least one splash; 20% (6) of which were heavily contaminated. The primary surgeon in a cesarean section was 1.6 times as likely to be splashed (P < 0.04) when compared with vaginal deliveries and 4.6 times as likely to be heavily contaminated (P < 0.003). Estimated blood loss and the rate of eye splash were linearly related. Method of delivery was not independently associated with eye splash. These findings suggest that the risk of contamination by splash during obstetric procedures is high, particularly for cesarean deliveries because these deliveries tend to have greater blood losses.

The structure of personality disorders in individuals with posttraumatic stress disorder

Research on the structure of personality disorders (PDs) has relied primarily on exploratory analyses to evaluate trait-based models of the factors underlying the covariation of these disorders. This study used confirmatory factor analysis to evaluate whether a model that included both PD traits and a general personality dysfunction factor would account for the comorbidity of the PDs better than a trait-only model. It also examined if the internalizing/externalizing model of psychopathology, developed previously through research on the structure of Axis I disorders, might similarly account for the covariation of the Axis II disorders in a sample of 245 veterans and nonveterans with posttraumatic stress disorder. Results indicated that the best fitting model was a modified bifactor structure composed of nine lower-order common factors. These factors indexed pathology ranging from aggression to dependency, with the correlations among them accounted for by higher-order Internalizing and Externalizing factors. Further, a general factor, reflecting a construct that we termed boundary disturbance, accounted for additional variance and covariance across nearly all the indicators. The Internalizing, Externalizing, and Boundary Disturbance factors evidenced differential associations with trauma-related covariates. These findings suggest continuity in the underlying structure of psychopathology across DSM-IV Axes I and II and provide empirical evidence of a pervasive, core disturbance in the boundary between self and other across the PDs.

Posttraumatic Stress Disorder Symptoms, Temperament, and the Pathway to Cellular Senescence

Traumatic stress is thought to be associated with shortened telomere length (TL) in leukocytes, an age-related marker of increased risk for cellular senescence, although findings thus far have been mixed. We assessed associations between posttraumatic stress disorder (PTSD) symptom severity, temperament, and TL in a sample of 453 White, non-Hispanic, middle-aged, trauma-exposed male and female veterans and civilians. Given that prior research has suggested an association between PTSD and accelerated cellular age, we also examined associations between TL and an index of accelerated cellular age derived from DNA methylation data (DNAm age). Analyses revealed that, controlling for chronological age, PTSD was not directly associated with TL but rather this association was moderated by age, β = -.14, p = .003, ΔR2 = .02. Specifically, PTSD severity evidenced a stronger negative association with TL among relatively older participants (≥ 55 years of age). In a subset of veterans with data pertaining to temperament (n = 150), positive emotionality, and, specifically, a drive toward achievement, β = .26, p = .002, ΔR2 = .06, were positively associated with TL. There was no evidence of an association between age-adjusted TL and accelerated DNAm age. Collectively, these results indicate that older adults may be more vulnerable to the negative health effects of PTSD but that traits such as achievement, resilience, and psychological hardiness may be protective. These findings underscore the importance of identifying reliable biomarkers of cellular aging and senescence and of determining the biological mechanisms that contribute to stress-related disease and decline.

Examining Individual and Synergistic Contributions of PTSD and Genetics to Blood Pressure: A Trans-Ethnic Meta-Analysis

Growing research suggests that posttraumatic stress disorder (PTSD) may be a risk factor for poor cardiovascular health, and yet our understanding of who might be at greatest risk of adverse cardiovascular outcomes after trauma is limited. In this study, we conducted the first examination of the individual and synergistic contributions of PTSD symptoms and blood pressure genetics to continuous blood pressure levels. We harnessed the power of the Psychiatric Genomics Consortium-PTSD Physical Health Working Group and investigated these associations across 11 studies of 72,224 trauma-exposed individuals of European (n = 70,870) and African (n = 1,354) ancestry. Genetic contributions to blood pressure were modeled via polygenic scores (PGS) for systolic blood pressure (SBP) and diastolic blood pressure (DBP) that were derived from a prior trans-ethnic blood pressure genome-wide association study (GWAS). Results of trans-ethnic meta-analyses revealed significant main effects of the PGS on blood pressure levels [SBP: β = 2.83, standard error (SE) = 0.06, p < 1E-20; DBP: β = 1.32, SE = 0.04, p < 1E-20]. Significant main effects of PTSD symptoms were also detected for SBP and DBP in trans-ethnic meta-analyses, though there was significant heterogeneity in these results. When including data from the largest contributing study - United Kingdom Biobank - PTSD symptoms were negatively associated with SBP levels (β = -1.46, SE = 0.44, p = 9.8E-4) and positively associated with DBP levels (β = 0.70, SE = 0.26, p = 8.1E-3). However, when excluding the United Kingdom Biobank cohort in trans-ethnic meta-analyses, there was a nominally significant positive association between PTSD symptoms and SBP levels (β = 2.81, SE = 1.13, p = 0.01); no significant association was observed for DBP (β = 0.43, SE = 0.78, p = 0.58). Blood pressure PGS did not significantly moderate the associations between PTSD symptoms and blood pressure levels in meta-analyses. Additional research is needed to better understand the extent to which PTSD is associated with high blood pressure and how genetic as well as contextual factors may play a role in influencing cardiovascular risk.