Immune function in PTSD

Innate and adaptive immune system consequences of post-traumatic stress disorder

In the field of psychiatry, biological markers are rarely, if ever, used in the diagnosis of mental health disorders. Clinicians rely primarily on patient histories and behavioral symptoms to identify specific psychopathologies, which makes diagnosis highly subjective. Moreover, therapies for mental health disorders are aimed specifically at attenuating behavioral manifestations, which overlooks the pathophysiological indices of the disease. This is highly evident in posttraumatic stress disorder (PTSD) where inflammation and immune system perturbations are becoming increasingly described. Further, patients with PTSD possess significantly elevated risks of developing comorbid inflammatory diseases such as autoimmune and cardiovascular diseases, which are likely linked (though not fully proven) to the apparent dysregulation of the immune system after psychological trauma. To date, there is little to no evidence that demonstrates current PTSD therapies are able to reverse the increased risk for psychological trauma-induced inflammatory diseases, which suggests the behavioral and somatic consequences of PTSD may not be tightly coupled. This observation provides an opportunity to explore unique mechanisms outside of the brain that contribute to the long-term pathology of PTSD. Herein, we provide an overview of neuroimmune mechanisms, describe what is known regarding innate and adaptive immunity in PTSD, and suggest new directions that are needed to advance the understanding, diagnosis, and treatment of PTSD moving forward.

Biological Correlates of Post-Traumatic Growth (PTG): A Literature Review

Since the beginning of medical science, much research have focused on the psychopathological effects of traumatic experiences. Despite in past centuries the scientific literature on mental health has been mainly focused on the harmful effects of traumatic occurrences, more recently the idea of "post-traumatic growth" emerged, on the basis of a growing interest in the characteristics of resilience and possible positive consequences of trauma. In this framework, increasing attention is now being paid to the psychological meaning of PTG, with a consistent number of psychopathological and epidemiological studies on this subject, but limited literature focused on neurobiological correlates or eventual biomarkers of this condition. The present work aimed to summarize and review the available evidence on neurobiological correlates of PTG and their psychological and clinical meaning. Results highlighted a variety of biochemical and neurobiological differences between PTG and non-PTG individuals, partially corroborating findings from earlier research on post-traumatic stress disorder (PTSD). However, although promising, findings in this field are still too limited and additional studies on the neurobiological correlates of traumatic experiences are needed in order to gain a better understanding of the subject.

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.

Dysregulated TP53 Among PTSD Patients Leads to Downregulation of miRNA let-7a and Promotes an Inflammatory Th17 Phenotype

Post-traumatic stress disorder (PTSD) is a psychiatric disorder and patients diagnosed with PTSD often express other comorbid health issues, particularly autoimmune and inflammatory disorders. Our previous reports investigating peripheral blood mononuclear cells (PBMCs) from PTSD patients showed that these patients exhibit an increased inflammatory T helper (Th) cell phenotype and widespread downregulation of microRNAs (miRNAs), key molecules involved in post-transcriptional gene regulation. A combination of analyzing prior datasets on gene and miRNA expression of PBMCs from PTSD and Control samples, as well as experiments using primary PBMCs collected from human PTSD and Controls blood, was used to evaluate TP53 expression, DNA methylation, and miRNA modulation on Th17 development. In the current report, we note several downregulated miRNAs were linked to tumor protein 53 (TP53), also known as p53. Expression data from PBMCs revealed that compared to Controls, PTSD patients exhibited decreased TP53 which correlated with an increased inflammatory Th17 phenotype. Decreased expression of TP53 in the PTSD population was shown to be associated with an increase in DNA methylation in the TP53 promotor region. Lastly, the most significantly downregulated TP53-associated miRNA, let-7a, was shown to negatively regulate Th17 T cells. Let-7a modulation in activated CD4+ T cells was shown to influence Th17 development and function, via alterations in IL-6 and IL-17 production, respectively. Collectively, these studies reveal that PTSD patients could be susceptible to inflammation by epigenetic dysregulation of TP53, which alters the miRNA profile to favor a proinflammatory Th17 phenotype.

Methylomic profiles reveal sex-specific differences in leukocyte composition associated with post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a debilitating mental disorder precipitated by trauma exposure. However, only some persons exposed to trauma develop PTSD. There are sex differences in risk; twice as many women as men develop a lifetime diagnosis of PTSD. Methylomic profiles derived from peripheral blood are well-suited for investigating PTSD because DNA methylation (DNAm) encodes individual response to trauma and may play a key role in the immune dysregulation characteristic of PTSD pathophysiology. In the current study, we leveraged recent methodological advances to investigate sex-specific differences in DNAm-based leukocyte composition that are associated with lifetime PTSD. We estimated leukocyte composition on a combined methylation array dataset (483 participants, ∼450 k CpG sites) consisting of two civilian cohorts, the Detroit Neighborhood Health Study and Grady Trauma Project. Sex-stratified Mann-Whitney U test and two-way ANCOVA revealed that lifetime PTSD was associated with significantly higher monocyte proportions in males, but not in females (Holm-adjusted p-val < 0.05). No difference in monocyte proportions was observed between current and remitted PTSD cases in males, suggesting that this sex-specific difference may reflect a long-standing trait of lifetime history of PTSD, rather than current state of PTSD. Associations with lifetime PTSD or PTSD status were not observed in any other leukocyte subtype and our finding in monocytes was confirmed using cell estimates based on a different deconvolution algorithm, suggesting that our sex-specific findings are robust across cell estimation approaches. Overall, our main finding of elevated monocyte proportions in males, but not in females with lifetime history of PTSD provides evidence for a sex-specific difference in peripheral blood leukocyte composition that is detectable in methylomic profiles and that may reflect long-standing changes associated with PTSD diagnosis.

Exercise Intervention in PTSD: A Narrative Review and Rationale for Implementation

Posttraumatic stress disorder (PTSD) is a prominent mental health problem in veteran and community populations. There is accumulating evidence to suggest that aerobic exercise may serve as an effective treatment option for individuals with PTSD. The purpose of this review is to summarize the existing literature exploring aerobic exercise and PTSD and briefly discuss potential mechanisms of PTSD symptom reduction. A search of electronic databases and reference sections of relevant articles published through October 1, 2018 revealed 19 relevant studies that examined aerobic exercise and PTSD symptomatology. A narrative review of extant studies provides encouraging evidence that aerobic exercise interventions alone or as an adjunct to standard treatment may positively impact PTSD symptoms. Potential mechanisms by which aerobic exercise could exert a positive impact in PTSD include exposure and desensitization to internal arousal cues, enhanced cognitive function, exercise-induced neuroplasticity, normalization of hypothalamic pituitary axis (HPA) function, and reductions in inflammatory markers. Randomized clinical trials and translational neuroscience approaches are required to clarify the efficacy of exercise intervention for PTSD and elucidate potential mechanisms of exercise-induced PTSD symptom reduction.

PTSD and Physical Health

PURPOSE OF REVIEW

We review evidence linking PTSD to physical health symptoms and specific disorders, highlighting areas with multiple studies and objective measures of disease states when available. We also examine evidence for biological, behavioral, and psychosocial mechanisms underlying these associations and discuss the clinical implications of recent research.

RECENT FINDINGS

Recent meta-analyses have found that evidence is particularly strong for increased risk of cardiovascular, metabolic, and musculoskeletal disorders among patients with PTSD. Numerous studies have found alterations in the hypothalamic-pituitary-adrenal axis, sympathetic nervous system, inflammation, and health behaviors that could increase risk of illness, but few studies have simultaneously incorporated measures of mechanisms and disease outcomes. Future research should focus on expanding the diversity of populations studied, particularly with respect to underrepresented racial and ethnic groups. Longitudinal studies that incorporate repeated measures of PTSD, pathogenic mechanisms of disease, and physical health outcomes and the addition of physical health outcomes to PTSD treatment trials will be most informative for the field.

Psychological Considerations and Interventions in Inflammatory Bowel Disease Patient Care

The presence of psychological comorbidities, specifically anxiety and depression, is well documented in inflammatory bowel disease (IBD). The drivers of these conditions typically reflect 4 areas of concern: disease impact, treatment concerns, intimacy, and stigma. Various demographic and disease characteristics increase risk for psychological distress. However, the risk for anxiety and depression is consistent throughout IBD course and is independent of disease activity. Early intervention before psychological distress becomes uncontrolled is ideal, but mental health often is unaddressed during patient visits. Understanding available psychological treatments and establishing referral resources is an important part of the evolution of IBD patient care.

Psychological Considerations and Interventions in Inflammatory Bowel Disease Patient Care

The presence of psychological comorbidities, specifically anxiety and depression, is well documented in inflammatory bowel disease (IBD). The drivers of these conditions typically reflect 4 areas of concern: disease impact, treatment concerns, intimacy, and stigma. Various demographic and disease characteristics increase risk for psychological distress. However, the risk for anxiety and depression is consistent throughout IBD course and is independent of disease activity. Early intervention before psychological distress becomes uncontrolled is ideal, but mental health often is unaddressed during patient visits. Understanding available psychological treatments and establishing referral resources is an important part of the evolution of IBD patient care.

Immune system changes after sexual abuse in adolescents

BACKGROUND

The immunological changes in diseases such as rheumatoid arthritis and multiple sclerosis have been found to be similar to the immunological changes in adults with post-traumatic stress disorder (PTSD). The biological consequences of and immunological disruptions associated with psychological trauma in sexually abused adolescents were investigated in this study.

METHODS

Number of peripheral blood cells, intracellular cytokine level and cytotoxic activity of natural killer cells were measured on routine blood examination samples in adolescents aged 13-18 referred to the outpatient unit for forensic evaluation. Forty-three adolescents (patients with present/lifetime PTSD [PTSD-P/PTSD-L] associated with a history of childhood sexual abuse, n = 33; and 10 controls) were evaluated.

RESULTS

Eosinophil percentage was high (P < 0.05), whereas stimulated intracellular interferon-γ was low (P < 0.05) in adolescents with PTSD-L compared with the control group. In PTSD-P patients exposed to repeated sexual abuse, CD3(+) HLA-DR(+) T-lymphocyte count was low (P < 0.05) compared with those with one-time sexual abuse.

CONCLUSION

The increase in some immune system parameters and the decrease in several others, suggests a dysregulation of the immune system related to trauma in adolescents. Dysregulation of the immune system is known to cause autoimmune and chronic disease.

Dysfunctional or hyperfunctional? The amygdala in posttraumatic stress disorder is the bull in the evolutionary China shop

Our motivation in writing this Review arose not only from the great value in contributing to this special issue of the Journal of Neuroscience Research but also from the desire to express our opinion that the description of the amygdala as "dysfunctional" in posttraumatic stress disorder (PTSD) might not be appropriate. We acknowledge that excessive activation of the amygdala contributes to the cluster of PTSD symptoms, including hypervigilance, intrusive memories, and impaired sleep, that underlies the devastating mental and physical outcomes in trauma victims. The issue that we address is whether the symptoms of PTSD represent an impaired (dysfunctional) or sensitized (hyperfunctional) amygdala status. We propose that the amygdala in PTSD is hyperfunctional rather than dysfunctional in recognition of the fact that the individual has already survived one life-threatening attack and that another may be forthcoming. We therefore consider PTSD to be a state in which the amygdala is functioning optimally if the goal is to ensure a person's survival. The misery caused by a hyperfunctional amygdala in PTSD is the cost of inheriting an evolutionarily primitive mechanism that considers survival more important than the quality of one's life.

How do duration, frequency, and intensity of exogenous CORT elevation affect immune outcomes of stress?

Stress is typically characterized as "acute" (lasting from minutes to hours) or "chronic" (lasting from days to months). These terms are of limited use as they are inconsistently used and only encompass one aspect of the stressor (duration). Short and long duration stress are generally thought to produce specific outcomes (e.g. acute stress enhances while chronic stress suppresses immune function). We propose that aspects of stress other than duration, such as frequency and intensity, are important in determining its outcome. We experimentally manipulated duration, frequency, and intensity of application of exogenous corticosterone, CORT, in Sceloporus undulatus (Eastern fence lizards) and measured the immune outcomes. Our findings reveal that immune outcomes of stress are not easily predicted from the average amount or duration of CORT elevation, but that intensity plays an important role. Although three of our treatments received the same average amount of CORT, they produced different effects on immune outcomes (hemagglutination). As predicted by the literature, short-duration exposure to low-dose CORT enhanced hemagglutination; however, short-duration exposure to high-dose CORT suppressed hemagglutination, suggesting that stressor intensity affects immune outcomes of stress. While both are traditionally termed "acute" based on duration, these treatments produced different immune outcomes. Long-duration ("chronic") exposure to CORT did not produce the expected suppression of hemagglutination. Frequency of CORT application did not alter immune outcomes at low intensities. These results highlight the need to quantify more than just the duration of a stressor if we are to understand and manage the ecological consequences of stress. Specifically, we should consider stressor frequency and intensity, as well as duration, for a more complete characterization and understanding of stress.

Patients with posttraumatic stress disorder exhibit an altered phenotype of regulatory T cells

BACKGROUND

Regulatory T cells (Tregs) play a key role in immune homeostasis in vivo. Tregs have a critical role in preventing the development of autoimmune diseases and defects in Treg function are implicated in various autoimmune disorders. Individuals with posttraumatic stress disorder (PTSD) have higher prevalence of autoimmune disorders than the general population. We hypothesized that war veterans with PTSD would exhibit a decreased number and/or altered phenotype of Tregs.

METHODS

We analyzed peripheral blood mononuclear cells (PBMCs) of patients with PTSD (N = 21) (mean age = 45.9) and age-matched healthy controls (N = 23) (mean age = 45.7) to determine the proportion of Tregs and their phenotype according to the expression of CD127 and HLA-DR markers which describe the differentiation stages of Tregs. In addition, we analyzed the expression of membrane ectoenzyme CD39 on Tregs of the study groups, an important component of the suppressive machinery of Tregs.

RESULTS

We found no differences in the proportion of Tregs between PTSD patients and controls, but PTSD patients had a higher percentage of CD127(-)HLA-DR(-) Tregs and a lower percentage of CD127(lo)HLA-DR(+) Tregs compared to controls. There was no difference in expression of CD39 on Tregs of the study groups.

CONCLUSIONS

Although the proportions of Tregs in PTSD patients were unchanged, we found that they exhibit a different phenotype of Tregs that might be less suppressive. Impaired differentiation and function of Tregs is likely involved in disruption of immune homeostasis in PTSD.

The effect of trauma-focused therapy on the altered T cell distribution in individuals with PTSD: evidence from a randomized controlled trial

Posttraumatic stress disorder (PTSD) is associated with a reduced ratio of naïve cytotoxic T lymphocytes, an increased ratio of memory cytotoxic T lymphocytes, and a reduced proportion of FoxP3(+) regulatory T lymphocytes. This study investigated whether these immunological alterations are reversible through an evidence-based psychotherapeutic treatment. Therefore, 34 individuals with PTSD were randomly assigned to either a treatment condition of 12 sessions narrative exposure therapy (NET) or a waitlist control (WLC) group. PTSD symptoms were significantly reduced in the NET group, but not in the WLC group, four months post-therapy (effect size: Hedges' g = -1.61). One year after therapy, PTSD symptoms were improved even further in the NET group compared to baseline (Hedges' g = -1.96). This symptom improvement was mirrored in an increase in the originally reduced proportion of regulatory T cells (Tregs) in the NET group at the one-year follow-up, when comparing subgroups matched for baseline Treg numbers. However, no changes were found for the initially reduced proportion of CD45RA(+)CCR7(+) naïve T lymphocytes. In conclusion, NET was effective in reducing trauma-related PTSD symptoms and had a positive effect on the proportion of Tregs cells, thus demonstrating an effect of psychotherapy on an immunological level. Yet, the shift in the proportion of naïve and memory T lymphocytes in individuals with PTSD, discussed in the literature as a correlate of premature immunosenescence, was not reversible and thus might render these patients permanently more susceptible to infectious diseases.

Mineralocorticoid receptor and heat shock protein expression levels in peripheral lymphocytes from war trauma-exposed men with and without PTSD

Alterations in the number and functional status of mineralocorticoid (MR) and glucocorticoid receptors (GR) may contribute to vulnerability to posttraumatic stress disorder (PTSD). Corticosteroid receptors are chaperoned by heat shock proteins Hsp90 and Hsp70. We examined relations between corticosteroid receptor and heat shock protein expression levels, and related them with war trauma exposure, PTSD and resilience to PTSD. Relative levels of MR, Hsp90 and Hsp70 were determined by immunoblotting in lymphocytes from war trauma-exposed men with current PTSD (current PTSD group, n=113), with life-time PTSD (life-time PTSD group, n=61) and without PTSD (trauma control group, n=88), and from non-traumatized healthy controls (healthy control group, n=85). Between-group differences in MR, Hsp90 and Hsp70 levels and in MR/GR ratio were not observed. The level of MR was correlated with both Hsp90 and Hsp70 levels in trauma control and healthy control groups. On the other hand, GR level was correlated only with Hsp90 level, and this correlation was evident in current PTSD and trauma control groups. In conclusion, PTSD and exposure to trauma are not related to changes in lymphocyte MR, Hsp90 or Hsp70 levels, but may be associated with disturbances in corticosteroid receptors interaction with heat shock proteins.

Chronic psychological stress suppresses contact hypersensitivity: potential roles of dysregulated cell trafficking and decreased IFN-γ production

Increasing evidence shows that psychological stress can have dramatic impacts on the immune system, particularly the cutaneous immune response in dermatological disorders. While there have been many studies examining the impact of acute psychological stress on contact hypersensitivity there are relatively few studies concerning the impact of chronic psychological stress. Furthermore, the local immunological mechanisms by which chronic psychological stress impacts contact hypersensitivity still remain to be explored. Here we show that restraint-induced chronic psychological stress stimulates activation of the hypothalamus-pituitary-adrenal axis and delays weight gain in female BALB/c mice. We observed that chronic psychological stress reduces the cutaneous immune response as evidence by reduced ear swelling. This correlated with a significant decrease in the inflammatory cell infiltrate. On the other hand, chronic psychological stress does not influence T cell proliferation, activation, or sensitivity to corticosterone but does increase CD4(+) and CD8(+) T cell percentages in draining lymph nodes during a contact hypersensitivity reaction. Chronic psychological stress induces a decrease in overall circulating white blood cells, lymphocytes, and monocytes during a contact hypersensitivity reaction suggesting extravasation from the circulation. Finally, we found markedly reduced local IFN-γ production in chronically stressed animals. Based on these findings we propose that chronic psychological stress reduces contact hypersensitivity due to dysregulated cell trafficking and reduced production of IFN-γ.

Neuroimmunoendocrine interactions in post-traumatic stress disorder: focus on long-term implications of childhood maltreatment

Childhood maltreatment has been linked to enhanced vulnerability to psychiatric pathologies in adult life, including post-traumatic stress disorder (PTSD). Previous works have reported cogent neuroendocrine and immune changes related to adult traumatic events (war survivors, refugees, etc.), but little information is known regarding the impact of early-life stress (ELS) in adult physiology. Here, we review the neuroendocrine and immunological changes commonly observed in PTSD, focusing on the long-term implications of ELS. Childhood maltreatment may lead to altered glucocorticoid (GC) secretion, resulting in hypo- or hypercortisolemia, and reciprocal changes in peripheral leukocyte sensitivity to GC. It is believed that these neuroendocrine changes are correlated with the immune imbalance phenomenon (low-grade inflammation), characterized by increased plasma levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and C-reactive protein. Changes in peripheral lymphocyte subsets are also documented, such as a reduction in regulatory T cells and an expansion of activated T cells. The excess of circulating cytokines may thus interfere with key brain neurotransmitter pathways involved in depression and enhanced risk to cardiovascular, respiratory, gastrointestinal, inflammatory and autoimmune diseases. Recent gene-environment and epigenetic findings have indicated potential molecular mechanisms linking ELS, neuroendocrine and immunity in PTSD.

A corticoid-sensitive cytokine release assay for monitoring stress-mediated immune modulation

The human immune system is orchestrated in a complex manner and protects the host against invading organisms and controls adequate immune responses to different antigen challenges in an endo-, auto- and paracrine-regulated fashion. The variety and intensity of immune responses are known to be dependent on stress-sensitive neural, humoral and metabolic pathways. The delayed-type hypersensitivity (DTH) skin test was a validated and standardized measure applied in clinical studies to monitor the integral function of cellular immune responses in vivo. The DTH skin test was, however, phased out in 2002. To obtain insight into the mechanisms of stress-sensitive immune reactions, we have developed an alternative in-vitro assay which allows the evaluation of antigen-dependent cellular immune responses triggered by T lymphocytes. The change in the concentration of proinflammatory cytokines in supernatant of the blood-antigen mixture is of particular interest to mirror the degree and adequacy of cellular immune responses. In this study we report that the proinflammatory cytokines interleukin (IL)-2, interferon (IFN)-γ and tumour necrosis factor (TNF)-α show a time-dependent increase upon ex-vivo bacterial, viral and fungal antigen stimulations. Furthermore, evidence is provided that this assay is sensitive to mirror stress hormone-mediated immune modulation in humans as shown either after hydrocortisone injection or after acute stress exposure during free fall in parabolic flight. This in-vitro test appears to be a suitable assay to sensitively mirror stress hormone-dependent inhibition of cellular immune responses in the human. Because of its standardization and relatively simple technical handling, it may also serve as an appropriate research tool in the field of psychoneuroendocrinology in clinical as in field studies.

Lymphocyte glucocorticoid receptor expression level and hormone-binding properties differ between war trauma-exposed men with and without PTSD

OBJECTIVE

Posttraumatic stress disorder (PTSD) has been shown to be associated with altered glucocorticoid receptor (GR) activity. We studied the expression and functional properties of the receptor in peripheral blood mononuclear cells (PBMCs) from non-traumatized healthy individuals (healthy controls; n=85), and war trauma-exposed individuals with current PTSD (n=113), with life-time PTSD (n=61) and without PTSD (trauma controls; n=88). The aim of the study was to distinguish the receptor alterations related to PTSD from those related to trauma itself or to resilience to PTSD.

METHODS

Functional status of the receptor was assessed by radioligand binding and lysozyme synthesis inhibition assays. The level of GR gene expression was measured by quantitative PCR and immunoblotting.

RESULTS

Current PTSD patients had the lowest, while trauma controls had the highest number of glucocorticoid binding sites (Bmax) in PBMCs. Hormone-binding potential (Bmax/KD ratio) of the receptor was diminished in the current PTSD group in comparison to all other study groups. Correlation between Bmax and KD that normally exists in healthy individuals was decreased in the current PTSD group. Contrasting Bmax data, GR protein level was lower in trauma controls than in participants with current or life-time PTSD.

CONCLUSIONS

Current PTSD is characterized by reduced lymphocyte GR hormone-binding potential and by disturbed compensation between Bmax and hormone-binding affinity. Resilience to PTSD is associated with enlarged fraction of the receptor molecules capable of hormone binding, within the total receptor molecule population in PBMCs.

Treatment-related reductions in PTSD and changes in physical health symptoms in women

This study examined the relationship between change in posttraumatic stress disorder (PTSD) symptoms over the course of PTSD treatment and the association with changes in general physical health symptoms. Both positive health habits (e.g., exercise) and negative (e.g., smoking), were examined to determine if they accounted for the association between changes in PTSD severity over time and changes in physical health. Participants were 150 women seeking treatment for PTSD. Latent growth curve modeling indicated a substantial relationship (R (2) = 34%) between changes in PTSD and changes in physical health that occurred during and shortly following treatment for PTSD. However, there was no evidence to suggest that changes in health behaviors accounted for this relationship. Thus, PTSD treatment can have beneficial effects on self-reported physical health symptoms, even without direct treatment focus on health per se, and is not accounted for by shifts in health behavior.

Acute pain speeds skin barrier recovery in healthy men and women

OBJECTIVE

Psychological stress is known to impair skin barrier recovery, but little is known about the impact of pain on skin healing processes. Our primary goals were to examine the degree to which acute pain affects recovery from skin barrier disruption, and the potential mediating impact of cortisol and catecholamines.

METHODS

Healthy non-smokers aged 18-43 (N = 53, 65% women) underwent a 3-minute cold pressor pain stimulus to their foot. Tape-stripping of forearm skin occurred at two separate locations: before (site 1) and after (site 2) the pain stimulus. Transepidural water loss (TEWL) was assessed at baseline (pre-stripping), immediately post-stripping, and at 75 min to determine skin barrier recovery. Cortisol and catecholamine responses were obtained from multiple saliva and plasma samples, respectively.

RESULTS

Contrary to expectations, greater pain was associated with faster skin barrier recovery, even after controlling for demographics, mood, anxiety, and other factors. Those who reported higher pain showed faster recovery at site 2 compared to a) individuals who experienced lower pain; and b) their own recovery at site 1. Greater increase in norepinephrine (but not in cortisol) was also associated with faster recovery at site 2, and mediated the impact of pain on recovery.

DISCUSSION

Results bolster evidence that acute pain can affect immune-related processes. It is possible that acute pain may speed recovery from dermal abrasions, although pain is likely to impair recovery from more severe wounds. As pain is an important potential target for clinical intervention, further investigation of pain, stress, and healing processes is warranted.

Increased number of activated T cells in lymphocyte subsets of maltreated children: data from a pilot study

OBJECTIVE

Maltreatment in childhood has been related to enduring changes in the immune system of adults, such as increased cell-mediated immune response.

PURPOSE

Due to the lack of data in children, this study examined lymphocyte subset numbers and distribution during youth.

METHODS

In 27 cases of 42 healthy but maltreated children, fully participating at follow-up 1-3years after the intervention of child protection team, and 19 cases of previously matched controls, analysis of blood samples by fluorescent activated cell sorter was consented.

RESULTS

With regard to age references, total lymphocyte counts were aberrant in maltreated children but not in controls. When compared to controls, the percentages and absolute numbers of activated (HLA-DR+) CD4+helper and CD8+cytotoxic T cells were significantly higher in maltreated children.

CONCLUSIONS

According to the typical distribution of HLA-DR+cells we assumed an increased stimulated cell-mediated immune function in maltreated children.

Stress and skin leukocyte trafficking as a dual-stage process

Stress responses are known to modulate leukocyte trafficking. In the skin, stress was reported both to enhance and reduce skin immunity, and the chronicity of stress exposure was suggested as a key determining factor. We here propose a dual-stage hypothesis, suggesting that stress, of any duration, reduces skin immunity during its course, while its cessation is potentially followed by a period of enhanced skin immunity. To start testing this hypothesis, rats were subcutaneously implanted with sterile surgical sponges for four-hours, during or after exposure to one of several acute stress paradigms, or to a chronic stress paradigm. Our findings, in both males and females, indicate that numbers of sponge-infiltrating leukocytes, and their specific subsets, were reduced during acute or chronic stress, and increased after stress cessation. Studying potential mediating mechanisms of the reduction in leukocyte numbers during acute stress, we found that neither adrenalectomy nor the administration of beta-adrenergic or glucocorticoid antagonists prevented this reduction. Additionally, administration of corticosterone or epinephrine to adrenalectomized rats did not impact skin leukocyte numbers, whereas, in the blood, these treatments did affect numbers of leukocytes and their specific subsets, as was also reported previously. Overall, our findings support the proposed dual-stage hypothesis, which can be evolutionally rationalized and accounts for most of the apparent inconsistencies in the literature regarding stress and skin immunity. Other aspects of the hypothesis should be tested, also using additional methodologies, and its predictions may bear clinical significance in treatment of skin disorders related to hyper- or hypo-immune function.

Inflammation and traumatic stress: the society to cells resiliency model to support integrative interventions

BACKGROUND

Posttraumatic stress disorder (PTSD) is a prevalent psychiatric disorder that develops following a traumatic event and has substantial health implications, including high rates of health morbidity and mortality, as well as significant health-related costs. Medical risks that are associated with PTSD often have an underlying inflammatory pathology, suggesting that inflammation contributes to these health declines.

OBJECTIVES AND DESIGN

In this critical literature review, the authors examine the medical risks associated with PTSD and the inflammatory mechanisms that likely underlie these risks.

RESULTS AND CONCLUSIONS

The authors offer a review of their "Cells to Society Resiliency Model" to motivate the development of integrative interventions that include factors of society, community, family, individual, physiological, and cellular factors to thereby reduce the health risks associated with PTSD.

Salivary measures of stress and immunity in police officers engaged in simulated critical incident scenarios

OBJECTIVE

This research investigated the effects of a critical incident lethal force scenario on a panel of salivary biomarkers, measured at baseline and then at 10 and 30 minutes postscenario, in 141 law enforcement volunteer officers.

METHODS

Officers were randomly assigned to two virtual reality scenarios. One scenario was brief and involved a police officer chasing a suspect on a motorcycle, confronting the suspect who draws a gun and shoots the police officer. The other scenario involved a lengthy chase by the police officer through a workplace of an armed perpetrator ultimately engaging in gunfire with the police officer. Saliva was analyzed for cortisol, secretory immunoglobulin A (sIgA), interleukin-6, and alpha-amylase concentrations.

RESULTS

The "workplace" scenario produced the largest responses in biomarkers, with significant rises in cortisol, interleukin-6, alpha-amylase, and secretory immunoglobulin A. These data suggest that virtual reality can produce stress and immune effects.

CONCLUSIONS

This research suggests that virtual reality scenarios produce physiologic stress responses, mimicking occupational stress.

Natural killer cell cytotoxicity and lymphocyte perforin expression in veterans with posttraumatic stress disorder

OBJECTIVE

To examine the effect of posttraumatic stress disorder (PTSD) on the measures of immune function and the hypothalamic-pituitary-adrenal axis components, and to determine whether additional life stressors affect measured variables.

METHODS

We simultaneously examined the natural killer cell cytotoxicity (NKCC), perforin and glucocorticoid receptor (GCR) expression in natural killer (NK) and cytotoxic T (CD8) cells, as well as serum cortisol concentration in a group of Croatian war veterans with chronic, combat-related PTSD (n=29) and a group of healthy, age-matched men (n=13). PTSD patients were divided into two subgroups: compensation-seeking (n=15) and retired or compensation non-seeking (n=14) subjects. The former includes those involved in the process of getting disability-based army retirement as an additional life stressor.

RESULTS

NKCC was decreased in both PTSD groups when compared to controls. Impairment of NKCC could not be attributed to the perforin expression as perforin was not decreased in comparison to controls. Moreover, the increased level of perforin was recorded in NK cells of retired PTSD subjects. Both PTSD groups shared an increased relative quantity of GCR in lymphocytes, whereas no difference between the groups in the baseline levels of serum cortisol was observed.

CONCLUSIONS

Diminished NKCC was not accompanied by perforin insufficiency in PTSD subjects, and other causes should be examined. An additional life stressor does not contribute considerably to either immune or endocrine system related changes.

Alterations in the complement cascade in post-traumatic stress disorder

Background

In the present study we assessed the functional state of the major mediator of the immune response, the complement system, in post-traumatic stress disorder (PTSD).

Methods

Thirty one PTSD patients within 13 years from traumatic event and the same number of sex- and age-matched healthy volunteers were involved in this study. In the blood serum of the study subjects hemolytic activities of the classical and alternative complement pathways, as well as the activities of the individual complement components have been measured. Correlation analysis between all measured parameters was also performed.

Results

According to the results obtained PTSD is characterized by hyperactivation of the complement classical pathway, hypoactivation of the complement alternative pathway and overactivation of the terminal pathway.

Conclusions

The results obtained provide further evidence on the involvement of the inflammatory component in pathogenesis of PTSD.

Substantial reduction of naïve and regulatory T cells following traumatic stress

Posttraumatic stress disorder (PTSD) is associated with an enhanced susceptibility to various somatic diseases. However, the exact mechanisms linking traumatic stress to subsequent physical health problems have remained unclear. This study investigated peripheral T lymphocyte differentiation subsets in 19 individuals with war and torture related PTSD compared to 27 non-PTSD controls (n=14 trauma-exposed controls; n=13 non-exposed controls). Peripheral T cell subpopulations were classified by their characteristic expression of the lineage markers CD45RA and CCR7 into: naïve (CD45RA(+) CCR7(+)), central memory (T(CM): CD45RA(-) CCR7(+)) and effector memory (T(EM): CD45RA(-) CCR7(-) and T(EMRA): CD45RA(-) CCR7(-)) cells. Furthermore, we analyzed regulatory T cells (CD4(+)CD25(+)FoxP3(+)) and ex vivo proliferation responses of peripheral blood mononuclear cells after stimulation with anti-CD3 monoclonal antibody. Results show that the proportion of naïve CD8(+) T lymphocytes was reduced by 32% (p=0.01), whereas the proportions of CD3(+) central (p=0.02) and effector (p=0.01) memory T lymphocytes were significantly enhanced (+22% and +34%, respectively) in PTSD patients compared to non-PTSD individuals. To a smaller extent, this effect was also observed in trauma-exposed non-PTSD individuals, indicating a cumulative effect of traumatic stress on T cell distribution. Moreover, PTSD patients displayed a 48% reduction in the proportion of regulatory T cells (p<0.001). Functionally, these alterations were accompanied by a significantly enhanced (+34%) ex vivo proliferation of anti-CD3 stimulated T cells (p=0.05). The profoundly altered composition of the peripheral T cell compartment might cause a state of compromised immune responsiveness, which may explain why PTSD patients show an increased susceptibility to infections, and inflammatory and autoimmune diseases.

PTSD is associated with an excess of inflammatory immune activities

PURPOSE. Post-traumatic stress disorder (PTSD) is associated with inflammatory-related medical conditions. This review examines studies of immune function in individuals with PTSD to determine if excessive inflammation is associated with PTSD. CONCLUSIONS. Current studies suggest an excess of inflammatory actions of the immune system in individuals with chronic PTSD. High levels of inflammatory cytokines have also been linked to PTSD vulnerability in traumatized individuals. There is also evidence that excessive inflammation is in part due to insufficient regulation by cortisol. PRACTICE IMPLICATIONS. An excess of inflammatory immune activity may contribute to health declines in individuals with PTSD, and treating PTSD symptoms may reduce these risks.

Psychological stress and wound healing in humans: a systematic review and meta-analysis

OBJECTIVE

The current review aims to synthesize existing knowledge about the relationship between psychological stress and wound healing.

METHODS

A systematic search strategy was conducted using electronic databases to search for published articles up to the end of October 2007. The reference lists of retrieved articles were inspected for further studies and citation searches were conducted. In addition, a meta-analysis of a subset of studies was conducted to provide a quantitative estimation of the influence of stress on wound healing.

RESULTS

Twenty-two papers met the inclusion criteria of the systematic review and a subsample of 11 was included in a meta-analysis. The studies assessed the impact of stress on the healing of a variety of wound types in different contexts, including acute and chronic clinical wounds, experimentally created punch biopsy and blister wounds, and minor damage to the skin caused by tape stripping. Seventeen studies in the systematic review reported that stress was associated with impaired healing or dysregulation of a biomarker related to wound healing. The relationship between stress and wound healing estimated by the meta-analysis was r=-0.42 (95% CI=-0.51 to -0.32) (P<.01).

CONCLUSION

Attention now needs to be directed towards investigating potential moderators of the relationship, mediating mechanisms underpinning the association, as well as the demonstration of a causal link by the development of experimental interventions in healthy populations.

How do cognition, emotion, and epileptogenesis meet? A study of emotional cognitive bias in temporal lobe epilepsy

Emotional distress is one of the most frequently reported seizure precipitants in epilepsy, but little is known about its causes and processes. Interestingly, it is now accepted that emotional distress, such as anxiety, may be accompanied by evolutionary adaptation, or abnormal attentional vigilance toward threatening stimuli. The goal of this research was to study the link between emotional seizure precipitants and pathological attention-related biases toward threat in temporal lobe epilepsy (TLE). To this aim, patients were asked to report the extent to which seizures were elicited or not by emotional precipitants, allowing distinction of two groups: "Emo-TLE" group and "Other-TLE" group. Attentional biases were investigated by comparing patients' emotional Stroop and dot detection paradigms with those of healthy individuals (control group). We found that the Emo-TLE group was characterized by attentional bias toward threatening stimuli compared with neutral stimuli and compared with the other two groups. We thus hypothesize that attentional biases related to threat in patients with TLE may sustain emotional vulnerability and seizure occurrence.

Low cortisol, high DHEA, and high levels of stimulated TNF-alpha, and IL-6 in women with PTSD

Posttraumatic stress disorder (PTSD) has been associated with hypothalamic-pituitary-adrenal (HPA) axis and immune function alterations; however, few studies have simultaneously investigated these systems in participants with PTSD. In this study, HPA axis and immune function in 26 women with PTSD with and without major depressive disorder was compared to 24 traumatized controls and to 21 nontraumatized controls. Posttraumatic stress disorder was associated with low cortisol and higher levels of DHEA and greater production of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) compared to traumatized and healthy controls. Women with PTSD and depression exhibited greater production of IL-6 and higher levels of dehydroepiandrosterone (DHEA) than those with PTSD, but without depression. These findings suggest dysregulated HPA axis and immune function in women with PTSD, and that comorbid depression may contribute to these abnormalities.