Inflamed by the flames? The impact of terrorism and war on immunity

Neurobiology and systems biology of stress resilience

Stress resilience is the phenomenon that some people maintain their mental health despite exposure to adversity or show only temporary impairments followed by quick recovery. Resilience research attempts to unravel the factors and mechanisms that make resilience possible and to harness its insights for the development of preventative interventions in individuals at risk for acquiring stress-related dysfunctions. Biological resilience research has been lagging behind the psychological and social sciences but has seen a massive surge in recent years. At the same time, progress in this field has been hampered by methodological challenges related to finding suitable operationalizations and study designs, replicating findings, and modeling resilience in animals. We embed a review of behavioral, neuroimaging, neurobiological, and systems biological findings in adults in a critical methods discussion. We find preliminary evidence that hippocampus-based pattern separation and prefrontal-based cognitive control functions protect against the development of pathological fears in the aftermath of singular, event-type stressors [as found in fear-related disorders, including simpler forms of posttraumatic stress disorder (PTSD)] by facilitating the perception of safety. Reward system-based pursuit and savoring of positive reinforcers appear to protect against the development of more generalized dysfunctions of the anxious-depressive spectrum resulting from more severe or longer-lasting stressors (as in depression, generalized or comorbid anxiety, or severe PTSD). Links between preserved functioning of these neural systems under stress and neuroplasticity, immunoregulation, gut microbiome composition, and integrity of the gut barrier and the blood-brain barrier are beginning to emerge. On this basis, avenues for biological interventions are pointed out.

PTSD and lower respiratory symptoms: A systematic review of longitudinal associations in early 9/11 World Trade Center responders

OBJECTIVE

The objective of this systematic review is to examine longitudinal associations between post-traumatic stress disorder (PTSD) and lower respiratory symptoms (LRS) specifically among responders present at the World Trade Center (WTC) site on September 11, 2001 (9/11). This group, which we refer to as "9/11 early responders," appears to have particularly high rates of both mental and physical illness relative to other 9/11-exposed populations.

METHODS

We performed a systematic literature review to examine associations between PTSD and LRS among 9/11 early responders in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews. After a structured search of Pubmed and the Fire Department of New York (FDNY) WTC bibliography for relevant articles, we identified 4 articles commenting on associations between PTSD and LRS in this population; all 4 passed quality review and were included in our primary analysis. 10 other articles we found in our research discussed rates of PTSD and LRS, but not associations between them, in the population in question; we commented on these in a secondary analysis.

RESULTS

The data demonstrate that there are significant associations between PTSD and LRS among 9/11 early responders. The data also suggest that both of these phenomena are more prevalent among 9/11 early responders relative to other 9/11-exposed populations.

CONCLUSIONS

These findings are relevant for optimizing care for the population in question, as well as for other survivors of past and future disasters with both psychiatric and medical sequelae.

PTSD, Immune System, and Inflammation

Posttraumatic stress disorder (PTSD) is a severe trauma and stress-related disorder associated with different somatic comorbidities, especially cardiovascular and metabolic disorders, and with chronic low-grade inflammation. Altered balance of the hypothalamic-pituitary-adrenal (HPA) axis, cytokines and chemokines, C-reactive protein, oxidative stress markers, kynurenine pathways, and gut microbiota might be involved in the alterations of certain brain regions regulating fear conditioning and memory processes, that are all altered in PTSD. In addition to the HPA axis, the gut microbiota maintains the balance and interaction of the immune, CNS, and endocrine pathways forming the gut-brain axis. Disbalance in the HPA axis, gut-brain axis, oxidative stress pathways and kynurenine pathways, altered immune signaling and disrupted homeostasis, as well as the association of the PTSD with the inflammation and disrupted cognition support the search for novel strategies for treatment of PTSD. Besides potential anti-inflammatory treatment, dietary interventions or the use of beneficial bacteria, such as probiotics, can potentially improve the composition and the function of the bacterial community in the gut. Therefore, bacterial supplements and controlled dietary changes, with exercise, might have beneficial effects on the psychological and cognitive functions in patients with PTSD. These new treatments should be aimed to attenuate inflammatory processes and consequently to reduce PTSD symptoms but also to improve cognition and reduce cardio-metabolic disorders associated so frequently with PTSD.

Posttraumatic Stress Disorder Mediates the Association between Traumatic World Trade Center Dust Cloud Exposure and Ongoing Systemic Inflammation in Community Members

Exposure to World Trade Center (WTC) dust/fumes and traumas on 11 September 2001 has been reported as a risk factor for post-traumatic stress disorder (PTSD) and other mental/physical health symptoms in WTC-affected populations. Increased systemic inflammation and oxidative stress from the exposure and subsequent illnesses have been proposed as contributors to the underlying biological processes. Many blood-based biomarkers of systemic inflammation, including C-reactive protein (CRP), are useful for non-invasive diagnostic and monitoring of disease process, and also potential targets for therapeutic interventions. Twenty years after 9/11, however, the relationships between WTC exposure, chronic PTSD, and systemic inflammation are only beginning to be systematically investigated in the WTC-affected civilian population despite the fact that symptoms of PTSD and systemic inflammation are still common and persistent. This paper aims to address this knowledge gap, using enrollees of the WTC Environmental Health Center (EHC), a federally designated treatment and surveillance program for community members (WTC Survivors) exposed to the 9/11 terrorist attack. We conducted a mediation analysis to investigate the association between acute WTC dust cloud traumatic exposure (WDCTE) on 9/11, chronic PTSD symptoms, and levels of systemic inflammation. The data indicate that the chronic PTSD symptoms and some specific symptom clusters of PTSD significantly mediate the WDCTE on systemic inflammation, as reflected by the CRP levels. As both chronic PTSD and systemic inflammation are long-term risk factors for neurodegeneration and cognitive decline, further research on the implications of this finding is warranted.

C-Reactive Protein: Marker of risk for post-traumatic stress disorder and its potential for a mechanistic role in trauma response and recovery

Increasing evidence indicates that inflammation plays a role in PTSD and stress disorder pathophysiology. PTSD is consistently associated with higher circulating inflammatory protein levels. Rodent models demonstrate that inflammation promotes enduring avoidance and arousal behaviors after severe stressors (e.g., predator exposure and social defeat), suggesting that inflammation may play a mechanistic role in trauma disorders. C-reactive protein (CRP) is an innate acute phase reactant produced by the liver after acute infection and chronic disease. A growing number of investigations report associations with PTSD diagnosis and elevated peripheral CRP, CRP gene mutations, and CRP gene expression changes in immune signaling pathways. CRP is reasonably established as a potential marker of PTSD and trauma exposure, but if and how it may play a mechanistic role is unclear. In this review, we discuss the current understanding of immune mechanisms in PTSD with a particular focus on the innate immune signaling factor, CRP. We found that although there is consistent evidence of an association of CRP with PTSD symptoms and risk, there is a paucity of data on how CRP might contribute to CNS inflammation in PTSD, and consequently, PTSD symptoms. We discuss potential mechanisms through which CRP could modulate enduring peripheral and CNS stress responses, along with future areas of investigation probing the role of CRP and other innate immune signaling factors in modulating trauma responses. Overall, we found that CRP likely contributes to central inflammation, but how it does so is an area for further study.

C-reactive protein, Epstein-Barr virus, and cortisol trajectories in refugee and non-refugee youth: Links with stress, mental health, and cognitive function during a randomized controlled trial

Experiencing childhood adversity has been associated with significant changes in inflammation, cell-mediated immunocompetence, and cortisol secretion. Relatively few studies have examined, longitudinally, alterations to inflammatory processes during adolescence, especially outside Western contexts; none have evaluated biomarker trajectories for at-risk youth in response to a structured behavioral intervention. We conducted a randomized controlled trial evaluating the efficacy of a humanitarian intervention targeting stress-alleviation, with 12-18 year-old Syrian refugees (n = 446) and Jordanian non-refugees (n = 371) living side-by-side in war-affected communities in Jordan. We measured C-reactive protein (CRP), Epstein-Barr virus antibodies (EBV), and hair cortisol concentration (HCC) at three timepoints (pre/post intervention and 11 month follow-up), and assessed three main outcomes (psychosocial stress, mental health, and cognitive function). Using growth mixture models, regressions, and growth curve models, we identified three distinct trajectories for CRP, two for EBV, and three for HCC, and examined their associations with age, gender, BMI, poverty, and trauma. We found associations with BMI for CRP, refugee status for EBV, and BMI and gender with HCC trajectory. In terms of health outcomes, we found associations between rising CRP levels and perceived stress (B =  -2.92, p = .007), and between HCC hypersecretion and insecurity (B = 7.21, p = .017). In terms of responses to the intervention, we observed no differential impacts by CRP or EBV trajectories, unlike HCC. These results suggest that commonly-assayed biomarkers do not associate with health outcomes and respond to targeted interventions in straightforward ways. Our study is the first to examine multiple biomarker trajectories in war-affected adolescents, in order to better evaluate the extent, timing, and malleability of the biological signatures of poverty, conflict, and forced displacement.

Advances in the molecular detection of tuberculosis in pre-contact Andean South America

Andean paleopathological research has significantly enhanced knowledge about the geographical distribution and evolution of tuberculosis (TB) in pre-Columbian South America. In this paper, we review the history and progress of research on ancient tuberculosis (TB) in the Andean region, focusing on the strengths and limitations of current approaches for the molecular detection of ancient pathogens, with special attention to TB. As a case study, we describe a molecular screening approach for the detection of ancient Mycobacterium tuberculosis in individuals from Late Intermediate Period (1000-1400 CE) contexts at the site of Huari, Peru. We evaluate 34 commingled human vertebrae and combine morphological assessments of pathology with high throughput sequencing and a non-selective approach to ancient pathogen DNA screening. Our method enabled the simultaneous detection of ancient M. tuberculosis DNA and an evaluation of the environmental microbial composition of each sample. Our results show that despite the dominance of environmental DNA, molecular signatures of M. tuberculosis were identified in eight vertebrae, six of which had no observable skeletal pathology classically associated tuberculosis infection. This screening approach will assist in the identification of candidate samples for downstream genomic analyses. The method permits higher resolution disease identification in cases where pathology may be absent, or where the archaeological context may necessitate a broad differential diagnosis based on morphology alone.

Political Efficacy as a Buffer of the Heightened Risk of Posttraumatic Stress in Disadvantaged Communities

External collective political efficacy (PE) is an individual's perception of the extent to which the government is responsive to the needs of his or her group or community or to its collective actions. Does PE play a role in the association between exposure to political violence and posttraumatic stress? The current study aimed to examine whether such PE may help explain why exposure to political violence results in posttraumatic stress for some people but not others. Based on the conservation of resource theory, research has found that residents of some types of communities are less likely to suffer from posttraumatic stress when exposed to political violence, due to the economic and psychological resources these communities provide. Political efficacy, as an individual-level factor that relates to the community, may help predict who will suffer more or less posttraumatic stress from exposure to political violence within a given community. Based on a panel study conducted immediately before and after the 2008-2009 Gaza conflict (N = 650) and hierarchical linear modeling analyses, we found that type of community indeed moderated the association between exposure to political violence and posttraumatic stress, Δ-2 log likelihood = 30.4, p < .001. In addition, we found that PE mitigated the psychological distress resulting from exposure to political conflict in disadvantaged communities, Δ-2 log likelihood = 22.8, p < .001. This study not only further untangled the association between exposure and distress during times of war but also identified the role that governments can play in preventing conflict-induced distress beyond offering physical protection.

Why We Hate

We offer a functional perspective on hate, showing that hate has a unique pattern of appraisals and action tendencies. Hate is based on perceptions of a stable, negative disposition of persons or groups. We hate persons and groups more because of who they are, than because of what they do. Hate has the goal to eliminate its target. Hate is especially significant at the intergroup level, where it turns already devalued groups into victims of hate. When shared among group members, hate can spread fast in conflict zones where people are exposed to hate-based violence, which further feeds their hate. Hate can be reassuring and self-protective, because its message is simple and helps confirming people’s belief in a just world.

Cross-Sectional and Longitudinal Associations of Chronic Posttraumatic Stress Disorder With Inflammatory and Endothelial Function Markers in Women

BACKGROUND

Posttraumatic stress disorder (PTSD) may contribute to heightened cardiovascular disease risk by promoting a proinflammatory state and impaired endothelial function. Previous research has demonstrated associations of PTSD with inflammatory and endothelial function biomarkers, but most work has been cross-sectional and does not separate the effects of trauma exposure from those of PTSD.

METHODS

We investigated associations of trauma exposure and chronic PTSD with biomarkers of inflammation (C-reactive protein and tumor necrosis factor alpha receptor II) and endothelial function (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in 524 middle-aged women in the Nurses' Health Study II. Using linear mixed models, we examined associations of trauma/PTSD status with biomarkers measured twice, 10 to 16 years apart, in cardiovascular disease-free women, considering either average levels over time (cross-sectional) or change in levels over time (longitudinal). Biomarker levels were log-transformed. Trauma/PTSD status (based on structured diagnostic interviews) was defined as no trauma at either blood draw (n = 175), trauma at blood draw 1 but no PTSD at either draw (n = 175), and PTSD that persisted beyond blood draw 1 (chronic PTSD; n = 174). The reference group was women without trauma.

RESULTS

In models adjusted for known potential confounders, women with chronic PTSD had higher average C-reactive protein (B = 0.27, p < .05), tumor necrosis factor alpha receptor II (B = 0.07, p < .01), and intercellular adhesion molecule-1 (B = 0.04, p < .05) levels. Women with trauma but without PTSD had higher average tumor necrosis factor alpha receptor II levels (B = 0.05, p < .05). In addition, women with chronic PTSD had a greater increase in vascular cell adhesion molecule-1 over time (B = 0.003, p < .05).

CONCLUSIONS

Increased inflammation and impaired endothelial function may be pathways by which chronic PTSD increases cardiovascular disease risk.

Elevated C-reactive protein and posttraumatic stress pathology among survivors of the 9/11 World Trade Center attacks

BACKGROUND

Systemic inflammation has emerged as a promising marker and potential mechanism underlying post-traumatic stress disorder (PTSD). The relationship between posttraumatic stress pathology and systemic inflammation has not, however, been consistently replicated and is potentially confounded by comorbid illness or injury, common complications of trauma exposure.

METHODS

We analyzed a large naturalistic cohort sharing a discrete physical and mental health trauma from the destruction of the World Trade Center (WTC) towers on September 11, 2001 (n = 641). We evaluated the relationship between multiple physical and mental health related indices collected through routine evaluations at the WTC Environmental Health Center (WTC EHC), a treatment program for community members exposed to the disaster. C-Reactive Protein (CRP), a marker of systemic inflammation, was examined in relation to scores for PTSD, PTSD symptom clusters (re-experiencing, avoidance, negative cognitions/mood, arousal), depression and anxiety, while controlling for WTC exposures, lower respiratory symptoms, age, sex, BMI and smoking as potential risks or confounders.

RESULTS

CRP was positively associated with PTSD severity (p < 0.001), trending toward association with depression (p = 0.06), but not with anxiety (p = 0.27). CRP was positively associated with re-experiencing (p < 0.001) and avoidance (p < 0.05) symptom clusters, and trended toward associations with negative cognitions/mood (p = 0.06) and arousal (p = 0.08).

CONCLUSIONS

In this large study of the relationship between CRP and posttraumatic stress pathology, we demonstrated an association between systemic inflammation and stress pathology (PTSD; trending with depression), which remained after adjusting for potentially confounding variables. These results contribute to research findings suggesting a salient relationship between inflammation and posttraumatic stress pathology.

How Personality Affects Vulnerability among Israelis and Palestinians following the 2009 Gaza Conflict

Can the onset of PTSD symptoms and depression be predicted by personality factors and thought control strategies? A logical explanation for the different mental health outcomes of individuals exposed to trauma would seem to be personality factors and thought control strategies. Trauma exposure is necessary but not sufficient for the development of PTSD. To this end, we assess the role of personality traits and coping styles in PTSD vulnerability among Israeli and Palestinian students amid conflict. We also determine whether gender and exposure level to trauma impact the likelihood of the onset of PTSD symptoms. Five questionnaires assess previous trauma, PTSD symptoms, demographics, personality factors and thought control strategies, which are analyzed using path analysis. Findings show that the importance of personality factors and thought control strategies in predicting vulnerability increases in the face of political violence: the higher stress, the more important the roles of personality and thought control strategies. Thought control strategies associated with introverted and less emotionally stable personality-types correlate positively with higher levels of PTSD symptoms and depression, particularly among Palestinians. By extension, because mental health is key to reducing violence in the region, PTSD reduction in conflict zones warrants rethinking.

The evolution of the molecular response to stress and its relevance to trauma and stressor-related disorders

The experience of "stress", in its broadest meaning, is an inevitable part of life. All living creatures have evolved multiple mechanisms to deal with such threats and challenges and to avoid damage to the organism that may be incurred from these stress responses. Trauma and stressor-related disorders are psychiatric conditions that are caused specifically by the experience of stress, though depression, anxiety and some other disorders may also be unleashed by stress. Stress, however, is not a mandatory criterion of these diagnoses. This article focuses on the evolution of the neurochemicals involved in the response to stress and the systems in which they function. This includes the skin and gut, and the immune system. Evidence suggests that responses to stress are evolutionarily highly conserved, have wider involvement than the hypothalamic pituitary adrenal stress axis alone, and that excessive stress responses can produce stressor-related disorders in both humans and animals.