A randomized, double-blind, placebo-controlled, crossover trial of mifepristone in Gulf War veterans with chronic multisymptom illness

Crisis in the gut: navigating gastrointestinal challenges in Gulf War Illness with bioengineering

Gulf War Illness (GWI) is characterized by a wide range of symptoms that manifests largely as gastrointestinal symptoms. Among these gastrointestinal symptoms, motility disorders are highly prevalent, presenting as chronic constipation, stomach pain, indigestion, diarrhea, and other conditions that severely impact the quality of life of GWI veterans. However, despite a high prevalence of gastrointestinal impairments among these veterans, most research attention has focused on neurological disturbances. This perspective provides a comprehensive overview of current in vivo research advancements elucidating the underlying mechanisms contributing to gastrointestinal disorders in GWI. Generally, these in vivo and in vitro models propose that neuroinflammation alters gut motility and drives the gastrointestinal symptoms reported in GWI. Additionally, this perspective highlights the potential and challenges of in vitro bioengineering models, which could be a crucial contributor to understanding and treating the pathology of gastrointestinal related-GWI.

Efficacy and Safety of Mifepristone in the Treatment of Male US Veterans With Posttraumatic Stress Disorder: A Phase 2a Randomized Clinical Trial

Importance

To date, no psychopharmacologic treatment has been found to be uniformly effective in veterans with posttraumatic stress disorder (PTSD); novel targets and approaches are needed to treat this disabling disorder.

Objective

To examine whether treatment with the glucocorticoid receptor antagonist mifepristone yields a signal for clinical efficacy in male veterans with PTSD.

Design, Setting, and Participants

This phase 2a, double-blind, parallel-group randomized clinical trial was conducted from November 19, 2012 (accrual started), through November 16, 2016 (final follow-up), within the US Department of Veterans Affairs. Participants were male veterans with chronic PTSD and a screening Clinician-Administered PTSD Scale score of 50 or higher. A total of 181 veterans consented to participation. Statistical analysis was conducted between August 2014 and May 2017.

Interventions

Participants were randomized in a 1:1 ratio to mifepristone (600 mg) or matched placebo taken orally for 7 days.

Main Outcomes and Measures

The clinical outcome was whether a veteran achieved a clinical response status (a reduction of ≥30% of total Clinician-Administered PTSD Scale score from baseline) at 4- and 12-week follow-up. On the basis of a binary statistical selection rule, a difference in the proportion of treatment vs control group responders of 15% would be a clinically relevant difference. Self-report measures of PTSD and associated symptoms were also obtained. Neuroendocrine outcomes and plasma levels of mifepristone were measured. Safety was assessed throughout the study. The primary analysis was based on a multiple imputation technique to address missing outcome data; thus, some participant numbers may not appear as whole numbers.

Results

A total of 81 veterans were enrolled and randomized. Excluding 1 participant randomized in error, 80 were included in the modified intention-to-treat analysis (41 randomized to mifepristone and 39 to placebo). The mean (SD) age was 43.1 (13.7) years. A total of 15.6 (38.1%) in the mifepristone group and 12.1 (31.1%) in the placebo group were clinical responders at 4 weeks in the analysis using the multiple imputation technique. The group difference in the proportion of clinical responders (7.0%) was less than the predefined margin of 15% indicating signal for clinical efficacy. In an exploratory analysis, the difference in response to mifepristone vs placebo in the subgroup with no lifetime history of traumatic brain injury (TBI) (7.0 [50.0%] vs 3.0 [27.3%]; difference, 22.7%) exceeded the efficacy margin at 4 weeks and was sustained at 12 weeks. In contrast, in veterans with PTSD and lifetime TBI, the response rate to mifepristone was lower than placebo at 12 weeks (7.4 [27.4%] vs 13.5 [48.3%]; difference, -20.9%).

Conclusions and Relevance

This study did not detect a signal for efficacy for mifepristone at 600 mg/d for 1 week in male veterans with chronic PTSD. Thus, this study does not support a phase 3 trial in this population. Future studies of mifepristone for the treatment of PTSD may be of interest in those without a history of TBI or in samples with a low base rate of lifetime head trauma.

Trial Registration

ClinicalTrials.gov Identifier: NCT01946685.

Enhancing Fear Extinction: Pharmacological Approaches

Extinction is the process by which the memory of a learned conditioned association decreases over time and with introduction of new associations. It is a vital part of fear learning, and it is critical to recovery in multiple fear-related disorders, including Specific and Social Phobias, Panic Disorder, Obsessive Compulsive Disorder (OCD), and Posttraumatic Stress Disorder (PTSD). The process of extinction is also the underlying mechanism for recovery in gold-standard therapies for PTSD, including prolonged exposure, cognitive processing therapy, eye movement desensitization and procession, as well as other empirically-based paradigms. Pharmacological modulators of extinction are thus promising targets for treatment of fear-related disorders. We focus here on emerging psychopharmacological treatments to facilitate extinction: D-cycloserine, scopolamine, losartan, ketamine, and 3,4-methylenedioxymethamphetamine. We also provide an overview of recent advances in molecular pathways that show promise as targets for extincion and inhibitory learning, including pathways related to cannabinoid, brain-derived neurotrophic factor, hypothalamic-pituitary-adrenal signaling, and promising work in neurosteroid compounds.

Systems consolidation and fear memory generalisation as a potential target for trauma-related disorders

Fear memory generalisation is a central hallmark in the broad range of anxiety and trauma-related disorders. Recent findings suggest that fear generalisation is closely related to hippocampal dependency during retrieval. In this review, we describe the current understanding about memory generalisation and its potential influence in fear attenuation through pharmacological and behavioural interventions. In light of systems consolidation framework, we propose that keeping memory precision could be a key step to enhance therapeutic outcomes.

Delayed treatment with the immunotherapeutic LNFPIII ameliorates multiple neurological deficits in a pesticide-nerve agent prophylactic mouse model of Gulf War Illness

Residual effects of the 1990-1991 Gulf War (GW) still plague veterans 30 years later as Gulf War Illness (GWI). Thought to stem mostly from deployment-related chemical overexposures, GWI is a disease with multiple neurological symptoms with likely immunological underpinnings. Currently, GWI remains untreatable, and the long-term neurological disease manifestation is not characterized fully. The present study sought to expand and evaluate the long-term implications of prior GW chemicals exposure on neurological function 6-8 months post GWI-like symptomatology induction. Additionally, the beneficial effects of delayed treatment with the glycan immunotherapeutic lacto-N-fucopentaose III (LNFPIII) were evaluated. Male C57BL/6J mice underwent a 10-day combinational exposure (i.p.) to GW chemicals, the nerve agent prophylactic pyridostigmine bromide (PB) and the insecticide permethrin (PM; 0.7 and 200 mg/kg, respectively). Beginning 4 months after PB/PM exposure, a subset of the mice were treated twice a week until study completion with LNFPIII. Evaluation of cognition/memory, motor function, and mood was performed beginning 1 month after LNFPIII treatment initiation. Prior exposure to PB/PM produced multiple locomotor, neuromuscular, and sensorimotor deficits across several motor tests. Subtle anxiety-like behavior was also present in PB/PM mice in mood tests. Further, PB/PM-exposed mice learned at a slower rate, mostly during early phases of the learning and memory tests employed. LNFPIII treatment restored or improved many of these behaviors, particularly in motor and cognition/memory domains. Electrophysiology data collected from hippocampal slices 8 months post PB/PM exposure revealed modest aberrations in basal synaptic transmission and long-term potentiation in the dorsal or ventral hippocampus that were improved by LNFPIII treatment. Immunohistochemical analysis of tyrosine hydroxylase (TH), a dopaminergic marker, did not detect major PB/PM effects along the nigrostriatal pathway, but LNFPIII increased striatal TH. Additionally, neuroinflammatory cells were increased in PB/PM mice, an effect reduced by LNFPIII. Collectively, long-term neurobehavioral and neurobiological dysfunction associated with prior PB/PM exposure was characterized; delayed LNFPIII treatment provided multiple behavioral and biological beneficial effects in the context of GWI, highlighting its potential as a GWI therapeutic.

Modeling Neuroimmune Interactions in Human Subjects and Animal Models to Predict Subtype-Specific Multidrug Treatments for Gulf War Illness

Gulf War Illness (GWI) is a persistent chronic neuroinflammatory illness exacerbated by external stressors and characterized by fatigue, musculoskeletal pain, cognitive, and neurological problems linked to underlying immunological dysfunction for which there is no known treatment. As the immune system and the brain communicate through several signaling pathways, including the hypothalamic–pituitary–adrenal (HPA) axis, it underlies many of the behavioral and physiological responses to stressors via blood-borne mediators, such as cytokines, chemokines, and hormones. Signaling by these molecules is mediated by the semipermeable blood–brain barrier (BBB) made up of a monocellular layer forming an integral part of the neuroimmune axis. BBB permeability can be altered and even diminished by both external factors (e.g., chemical agents) and internal conditions (e.g., acute or chronic stress, or cross-signaling from the hypothalamic–pituitary–gonadal (HPG) axis). Such a complex network of regulatory interactions that possess feed-forward and feedback connections can have multiple response dynamics that may include several stable homeostatic states beyond normal health. Here we compare immune and hormone measures in the blood of human clinical samples and mouse models of Gulf War Illness (GWI) subtyped by exposure to traumatic stress for subtyping this complex illness. We do this via constructing a detailed logic model of HPA–HPG–Immune regulatory behavior that also considers signaling pathways across the BBB to neuronal–glial interactions within the brain. We apply conditional interactions to model the effects of changes in BBB permeability. Several stable states are identified in the system beyond typical health. Following alignment of the human and mouse blood profiles in the context of the model, mouse brain sample measures were used to infer the neuroinflammatory state in human GWI and perform treatment simulations using a genetic algorithm to optimize the Monte Carlo simulations of the putative treatment strategies aimed at returning the ill system back to health. We identify several ideal multi-intervention strategies and potential drug candidates that may be used to treat chronic neuroinflammation in GWI.

A review of pre-clinical models for Gulf War Illness

Gulf War Illness (GWI) is a chronic multisymptomatic disorder that afflicts over 1/3rd of the 1991 GW veterans. It spans multiple bodily systems and presents itself as a syndrome exhibiting diverse symptoms including fatigue, depression, mood, and memory and concentration deficits, musculoskeletal pain and gastrointestinal distress in GW veterans. The etiology of GWI is complex and many factors, including chemical, physiological, and environmental stressors present in the GW arena, have been implicated for its development. It has been over 30 years since the end of the GW but, GWI has been persistent in suffering veterans who are also dealing with paucity of effective treatments. The multifactorial aspect of GWI along with genetic heterogeneity and lack of available data surrounding war-time exposures have proved to be challenging in developing pre-clinical models of GWI. Despite this, over a dozen GWI animal models exist in the literature. In this article, following a brief discussion of GW history, GWI definitions, and probable causes for its pathogenesis, we will expand upon various experimental models used in GWI laboratory research. These animal models will be discussed in the context of their attempts at mimicking GW-related exposures with regards to the variations in chemical combinations, doses, and frequency of exposures. We will discuss their advantages and limitations in modeling GWI followed by a discussion of behavioral and molecular findings in these models. The mechanistic data obtained from these preclinical studies have offered multiple molecular pathways including chronic inflammation, mitochondrial dysfunction, oxidative stress, lipid disturbances, calcium homeostatic alterations, changes in gut microbiota, and epigenetic modifications, amongst others for explaining GWI development and its persistence. Finally, these findings have also informed us on novel druggable targets in GWI. While, it has been difficult to conceive a single pre-clinical model that could express all the GWI signs and exhibit biological complexity reflective of the clinical presentation in GWI, animal models have been critical for identifying molecular underpinnings of GWI and evaluating treatment strategies for GWI.

The effect of stress on the transcriptomes of circulating immune cells in patients with Gulf War Illness

AIMS

In an effort to gain further insight into the underlying mechanisms tied to disease onset and progression of Gulf War Illness (GWI), our team evaluated GWI patient response to stress utilizing RNA-Seq.

MAIN METHODS

The protocol included blood collection before exercise challenge (baseline), at maximal exertion, and after exercise challenge (recovery - four hours post-exercise challenge). Peripheral blood mononuclear cell (PBMC) transcriptomics data were analyzed to understand why GWI patients process stressors differently from their healthy counterparts.

KEY FINDINGS

Our findings validate previously identified dysregulation of immune and inflammatory pathways among GWI patients as well as highlight novel immune and inflammatory markers of disease activity. These results provide a foundation for future research efforts in understanding GWI pathophysiology and creating targeted treatments.

SIGNIFICANCE

Gulf War Illness is a complex, chronic, and debilitating multi-system illness impacting 25%-30% of the U.S. troops deployed to the 1990-1991 Gulf War. The condition is characterized by medically unexplained fatigue and affects multiple organ systems. Because the underlying mechanisms are largely unknown, patients receive symptom-based treatment, rather than targeting fundamental biological processes. To the best of our knowledge, this is the first study that applies RNA-Seq to analyze the effect of GWI, and the response to stressors in GWI, on the transcriptomic changes in circulating immune cells.

Host gut microbiome and potential therapeutics in Gulf War Illness: A short review

AIMS

Since our troops had returned from the first Persian Gulf War in 1990-91, the veterans have reported chronic multisymptomatic illness widely referred to as Gulf War Illness (GWI). We aim to review the current directions of GWI pathology research in the context of chronic multisymptomatic illness and its possible gut microbiome targeted therapies. The veterans of Gulf War show symptoms of chronic fatigue, cognitive deficits, and a subsection report of gastrointestinal complications.

METHOD

Efforts of finding a suitable treatment regimen and clinical management remain a challenge. More recently, we have shown that the pathology is connected to alterations in the gut microbiome, and efforts of finding a suitable regimen for gut-directed therapeutics are underway. We discuss the various clinical interventions and summarize the possible effectiveness of gut-directed therapies such as the use of short-chain fatty acids (SCFA), phenolic compounds, and their metabolites, use of probiotics, and fecal microbiota transfer.

SIGNIFICANCE

The short review will be helpful to GWI researchers to expand their studies to the gut and find an effective treatment strategy for chronic multisymptomatic illness.

Lacto-N-fucopentaose-III ameliorates acute and persisting hippocampal synaptic plasticity and transmission deficits in a Gulf War Illness mouse model

AIMS

The present study investigated if treatment with the immunotherapeutic, lacto-N-fucopentaose-III (LNFPIII), resulted in amelioration of acute and persisting deficits in synaptic plasticity and transmission as well as trophic factor expression along the hippocampal dorsoventral axis in a mouse model of Gulf War Illness (GWI).

MAIN METHODS

Mice received either coadministered or delayed LNFPIII treatment throughout or following, respectively, exposure to a 15-day GWI induction paradigm. Subsets of animals were subsequently sacrificed 48 h, seven months, or 11 months post GWI-related (GWIR) exposure for hippocampal qPCR or in vitro electrophysiology experiments.

KEY FINDINGS

Progressively worsened impairments in hippocampal synaptic plasticity, as well as a biphasic effect on hippocampal synaptic transmission, were detected in GWIR-exposed animals. Dorsoventral-specific impairments in hippocampal synaptic responses became more pronounced over time, particularly in the dorsal hippocampus. Notably, delayed LNFPIII treatment ameliorated GWI-related aberrations in hippocampal synaptic plasticity and transmission seven and 11 months post-exposure, an effect that was consistent with enhanced hippocampal trophic factor expression and absence of increased interleukin 6 (IL-6) in animals treated with LNFPIII.

SIGNIFICANCE

Approximately a third of Gulf War Veterans have GWI; however, GWI therapeutics are presently limited to targeted and symptomatic treatments. As increasing evidence underscores the substantial role of persisting neuroimmune dysfunction in GWI, efficacious neuroactive immunotherapeutics hold substantial promise in yielding GWI remission. The findings in the present report indicate that LNFPIII may be an efficacious candidate for ameliorating persisting neurological abnormalities presented in GWI.

A Pilot Study to Examine Psychological and Neuropsychological Outcomes and a Novel Detoxification Program for Gulf War Illness

INTRODUCTION

Exposures to environmental toxins have been associated with severe health problems for approximately one-quarter of the nearly 700,000 U.S. soldiers who served in the Gulf War between the years 1990 and 1991. Gulf War illness still affects about 30% of Gulf War veterans (GWV), causing reduced psychological wellness and neuropsychological function.

METHOD AND MATERIALS

This pilot study used a randomized wait-list control design to explore the feasibility and efficacy of a novel detoxification method for GWV exposed to toxicants such as pesticides, nerve gases, and pyridostigmine bromide. Our study included 32 GWV (67% male), with a mean age of 51 (range: 43-70, SD = 6.97), who participated in a 4- to 5-week treatment that was hypothesized to reduce the reported psychological and neuropsychological symptoms. Psychological measures used included tests given for the evaluation of neurocognitive function, including motor function for a dominant hand with the grooved pegboard test; verbal and visual immediate and delayed memory with the Wechsler Memory Scale III abbreviated subtests; executive function domains of attention, speed, and mental flexibility with trail making test parts A and B and Stroop color and word test. Psychological status was measured using the nine subscales of the Symptom Checklist-90-Revised.

RESULTS

Primary outcomes included between-group differences in self-reported psychological measures and a neuropsychological battery at 7-day and 3-month assessments. Baseline comparison revealed improvements in 16 of 19 psychological and neuropsychological measures at 7-day assessment and that 13 remained stable at 3-month assessment.

CONCLUSIONS

We conclude that the detoxification procedure provided improvement in psychological and cognitive function for GWV and that future study is warranted.

Mifepristone enhances the neural efficiency of human visuospatial memory encoding and recall

Glucocorticoid receptor (GR) antagonism is a promising new treatment for cognitive dysfunction in psychiatric disorders but the effects of GR antagonism on cognition related brain activity is poorly understood. This study examines the effects of the GR and progesterone receptor antagonist mifepristone on the neural correlates of visuospatial learning and working memory in healthy male participants. The study used a pharmacological functional magnetic resonance imaging (fMRI) design to determine mifepristone effects on visuospatial paired associates learning (vPAL) and n-back working memory (WM) fMRI task related brain activations. 20 right-handed healthy male participants received 600 mg mifepristone or placebo on two separate imaging days and each participant performed fMRI tasks four hours later. The effect of mifepristone on task related brain activations was determined using Region of Interest (ROI) fMRI analyses and an exploratory whole brain voxel-wise fMRI task analyses was also conducted. The vPAL task ROI analysis found that mifepristone administration was significantly associated with decreased fusiform cortex activations in first and second encoding blocks (p = 0.007, p = 0.04) and decreased angular and precuneal cortices activations in the first recall block (p = 0.01, p = 0.02). There were no significant differences in fMRI brain activations associated with mifepristone administration in the n-back task ROI's (all p > 0.05). Mifepristone administration did not significantly affect fMRI brain activations in the whole brain voxel-wise analyses for both tasks. N-back and vPAL task reaction times and accuracy were similar in both mifepristone and placebo conditions (all p > 0.05). Our finding of decreased fusiform, angular and precuneal vPAL task related brain activity associated with mifepristone administration for the same behavioural performance as found in the placebo condition may represent improved efficiency of visuospatial memory encoding and recall. These findings provide evidence that mifepristone may enhance the efficiency of human visuospatial memory and calls for further studies in patient populations using an fMRI approach to provide proof of concept for new treatments.

A Systematic Review of Therapeutic Interventions and Management Strategies for Gulf War Illness

Introduction

After the 1990 to 1991 conflict in the Persian Gulf, many Gulf War Veterans began reporting numerous unexplained symptoms including, but not limited to, systemic pain, fatigue, flu-like symptoms, and difficulty with memory/concentration. These symptom clusters are now referred to as Gulf War Illness (GWI). Although the etiology of GWI is still debated, as many as 250,000 former service members have been continually suffering from GWI since 1991, making the need for treatment urgent. A broad variety of treatments have been considered for GWI, but there has not been a broad and comprehensive assessment of what is known and not known about GWI treatment. We conducted a systematic review to catalogue the types of treatments that have been examined for GWI, to evaluate the effectiveness and harms of these interventions, and to identify promising and ongoing areas of future GWI treatment research.

Materials and Methods

We searched electronic databases, trial registries, and reference lists through September 2019 for randomized controlled trial and nonrandomized controlled trial and cohort studies directly comparing interventions for Veterans with GWI to each other, placebo, or usual care. We abstracted data on study design, demographics, interventions, and outcomes. Two reviewers independently assessed studies for inclusion, quality, and strength of evidence (SOE) using prespecified criteria. We resolved discordant ratings by discussion and consensus.

Results

We identified 12 randomized controlled trials, each of which examined a different intervention for GWI. We found moderate SOE that cognitive behavioral therapy and exercise, separately and in combination, were associated with improvements in several GWI symptom domains. There was low SOE of benefit from two mindfulness-based interventions and continuous positive airway pressure (CPAP). Mindfulness-based stress reduction improved pain, cognitive functioning, fatigue, depression, and posttraumatic stress disorder (PTSD), whereas mind-body bridging improved fatigue, depression, posttraumatic stress disorder, and sleep, although pain and other outcomes did not improve. Continuous positive airway pressure improved overall physical health, pain, cognitive functioning, fatigue, mental health, and sleep quality in a small study of Veterans with sleep-disordered breathing and GWI. We found moderate SOE that doxycycline is ineffective for GWI in mycoplasma DNA-positive Veterans and increases the risk of adverse events compared with placebo. We also found 33 ongoing, single-arm pilot, or unpublished studies examining a variety of interventions.

Conclusion

Cognitive behavioral therapy (moderate SOE), exercise (moderate SOE), and mindfulness-based interventions (low SOE) may be effective in improving several symptom domains in patients with GWI. Doxycycline was ineffective and associated with harms (moderate SOE). Larger, more rigorous studies are needed to confirm the benefits found in completed trials. A wide array of treatments are being assessed in ongoing trials. A sufficient evidence base will need to be developed to guide clinicians about which treatments are most likely to be effective in clinical practice and which treatments should be avoided.

Therapeutic implications of hypothalamic-pituitaryadrenal-axis modulation in Alzheimer's disease: A narrative review of pharmacological and lifestyle interventions

With disease-modifying treatments for Alzheimer's disease (AD) still elusive, the search for alternative intervention strategies has intensified. Growing evidence suggests that dysfunction in hypothalamic-pituitaryadrenal-axis (HPAA) activity may contribute to the development of AD pathology. The HPAA, may therefore offer a novel target for therapeutic action. This review summarises and critically evaluates animal and human studies investigating the effects of pharmacological and non-pharmacological intervention on HPAA modulation alongside cognitive performance. The interventions discussed include glucocorticoid receptor antagonists and 11β-hydroxysteroid dehydrogenase inhibitors as well as lifestyle treatments such as physical activity, diet, sleep and contemplative practices. Pharmacological HPAA modulators improve pathology and cognitive deficit in animal AD models, but human pharmacological trials are yet to provide definitive support for such benefits. Lifestyle interventions may offer promising strategies for HPAA modification and cognitive health, but several methodological caveats across these studies were identified. Directions for future research in AD studies are proposed.

The social ecology of childhood and early life adversity

An increasing prevalence of early childhood adversity has reached epidemic proportions, creating a public health crisis. Rather than focusing only on adverse childhood experiences (ACEs) as the main lens for understanding early childhood experiences, detailed assessments of a child's social ecology are required to assess "early life adversity." These should also include the role of positive experiences, social relationships, and resilience-promoting factors. Comprehensive assessments of a child's physical and social ecology not only require parent/caregiver surveys and clinical observations, but also include measurements of the child's physiology using biomarkers. We identify cortisol as a stress biomarker and posit that hair cortisol concentrations represent a summative and chronological record of children's exposure to adverse experiences and other contextual stressors. Future research should use a social-ecological approach to investigate the robust interactions among adverse conditions, protective factors, genetic and epigenetic influences, environmental exposures, and social policy, within the context of a child's developmental stages. These contribute to their physical health, psychiatric conditions, cognitive/executive, social, and psychological functions, lifestyle choices, and socioeconomic outcomes. Such studies must inform preventive measures, therapeutic interventions, advocacy efforts, social policy changes, and public awareness campaigns to address early life adversities and their enduring effects on human potential. IMPACT: Current research does not support the practice of using ACEs as the main lens for understanding early childhood experiences. The social ecology of early childhood provides a contextual framework for evaluating the long-term health consequences of early life adversity. Comprehensive assessments reinforced with physiological measures and/or selected biomarkers, such as hair cortisol concentrations to assess early life stress, may provide critical insights into the relationships between early adversity, stress axis regulation, and subsequent health outcomes.

Gulf War Illness: Mechanisms Underlying Brain Dysfunction and Promising Therapeutic Strategies

Gulf War Illness (GWI), a chronic multisymptom health problem, afflicts ~30% of veterans served in the first GW. Impaired brain function is among the most significant symptoms of GWI, which is typified by persistent cognitive and mood impairments, concentration problems, headaches, chronic fatigue, and musculoskeletal pain. This review aims to discuss findings from animal prototypes and veterans with GWI on mechanisms underlying its pathophysiology and emerging therapeutic strategies for alleviating brain dysfunction in GWI. Animal model studies have linked brain impairments to incessantly elevated oxidative stress, chronic inflammation, inhibitory interneuron loss, altered lipid metabolism and peroxisomes, mitochondrial dysfunction, modified expression of genes relevant to cognitive function, and waned hippocampal neurogenesis. Furthermore, the involvement of systemic alterations such as the increased intensity of reactive oxygen species and proinflammatory cytokines in the blood, transformed gut microbiome, and activation of the adaptive immune response have received consideration. Investigations in veterans have suggested that brain dysfunction in GWI is linked to chronic activation of the executive control network, impaired functional connectivity, altered blood flow, persistent inflammation, and changes in miRNA levels. Lack of protective alleles from Class II HLA genes, the altered concentration of phospholipid species and proinflammatory factors in the circulating blood have also been suggested as other aiding factors. While some drugs or combination therapies have shown promise for alleviating symptoms in clinical trials, larger double-blind, placebo-controlled trials are needed to validate such findings. Based on improvements seen in animal models of GWI, several antioxidants and anti-inflammatory compounds are currently being tested in clinical trials. However, reliable blood biomarkers that facilitate an appropriate screening of veterans for brain pathology need to be discovered. A liquid biopsy approach involving analysis of brain-derived extracellular vesicles in the blood appears efficient for discerning the extent of neuropathology both before and during clinical trials.

The Innate Immune System and Inflammatory Priming: Potential Mechanistic Factors in Mood Disorders and Gulf War Illness

Gulf War Illness is a chronic multisystem disorder affecting approximately a third of the Veterans of the Gulf War, manifesting with physical and mental health symptoms such as cognitive impairment, neurological abnormalities, and dysregulation of mood. Among the leading theories into the etiology of this multisystem disorder is environmental exposure to the various neurotoxins encountered in the Gulf Theatre, including organophosphates, nerve agents, pyridostigmine bromide, smoke from oil well fires, and depleted uranium. The relationship of toxin exposure and the pathogenesis of Gulf War Illness converges on the innate immune system: a nonspecific form of immunity ubiquitous in nature that acts to respond to both exogenous and endogenous insults. Activation of the innate immune system results in inflammation mediated by the release of cytokines. Cytokine mediated neuroinflammation has been demonstrated in a number of psychiatric conditions and may help explain the larger than expected population of Gulf War Veterans afflicted with a mood disorder. Several of the environmental toxins encountered by soldiers during the first Gulf War have been shown to cause upregulation of inflammatory mediators after chronic exposure, even at low levels. This act of inflammatory priming, by which repeated exposure to chronic subthreshold insults elicits robust responses, even after an extended period of latency, is integral in the connection of Gulf War Illness and comorbid mood disorders. Further developing the understanding of the relationship between environmental toxin exposure, innate immune activation, and pathogenesis of disease in the Gulf War Veterans population, may yield novel therapeutic targets, and a greater understanding of disease pathology and subsequently prevention.

A Detoxification Intervention for Gulf War Illness: A Pilot Randomized Controlled Trial

Approximately 30% of the 700,000 US veterans of the 1990-1991 Persian Gulf War developed multiple persistent symptoms called Gulf War illness. While the etiology is uncertain, several toxic exposures including pesticides and chemical warfare agents have shown associations. There is no effective medical treatment. An intervention to enhance detoxification developed by Hubbard has improved quality of life and/or reduced body burdens in other cohorts. We evaluated its feasibility and efficacy in ill Gulf War (GW) veterans in a randomized, waitlist-controlled, pilot study at a community-based rehabilitation facility in the United States. Eligible participants (n = 32) were randomly assigned to the intervention (n = 22) or a four-week waitlist control (n = 10). The daily 4-6 week intervention consisted of exercise, sauna-induced sweating, crystalline nicotinic acid and other supplements. Primary outcomes included recruitment, retention and safety; and efficacy was measured via Veteran's Short Form-36 (SF-36) quality of life, McGill pain, multidimensional fatigue inventory questionnaires and neuropsychological batteries. Scoring of outcomes was blinded. All 32 completed the trial and 21 completed 3-month follow-up. Mean SF-36 physical component summary score after the intervention was 6.9 (95% CI; -0.3, 14.2) points higher compared to waitlist control and 11 of 16 quality of life, pain and fatigue measures improved, with no serious adverse events. Most improvements were retained after 3 months. The Hubbard regimen was feasible, safe and might offer relief for symptoms of GW illness.

Progression of intervention-focused research for Gulf War illness

The Persian Gulf War of 1990 to 1991 involved the deployment of nearly 700,000 American troops to the Middle East. Deployment-related exposures to toxic substances such as pesticides, nerve agents, pyridostigmine bromide (PB), smoke from burning oil wells, and petrochemicals may have contributed to medical illness in as many as 250,000 of those American troops. The cluster of chronic symptoms, now referred to as Gulf War Illness (GWI), has been studied by many researchers over the past two decades. Although over $500 million has been spent on GWI research, to date, no cures or condition-specific treatments have been discovered, and the exact pathophysiology remains elusive.Using the 2007 National Institute of Health (NIH) Roadmap for Medical Research model as a reference framework, we reviewed studies of interventions involving GWI patients to assess the progress of treatment-related GWI research. All GWI clinical trial studies reviewed involved investigations of existing interventions that have shown efficacy in other diseases with analogous symptoms. After reviewing the published and ongoing registered clinical trials for cognitive-behavioral therapy, exercise therapy, acupuncture, coenzyme Q10, mifepristone, and carnosine in GWI patients, we identified only four treatments (cognitive-behavioral therapy, exercise therapy, CoQ10, and mifepristone) that have progressed beyond a phase II trial.We conclude that progress in the scientific study of therapies for GWI has not followed the NIH Roadmap for Medical Research model. Establishment of a standard case definition, prioritized GWI research funding for the characterization of the pathophysiology of the condition, and rapid replication and adaptation of early phase, single site clinical trials could substantially advance research progress and treatment discovery for this condition.

Neuropsychological Findings in Gulf War Illness: A Review

This review paper summarizes the accumulation of research investigating neuropsychological outcomes in veterans with Gulf War illness (GWI). Earlier research focused on Gulf War veterans (GW) who were deployed versus non-deployed, as well as those who were symptomatic versus asymptomatic, or compared neuropsychological test results to published norms. Further research became more sophisticated, investigating specific GWI criteria, as well as the result of neurotoxicant exposure and the relationship to possible neurocognitive outcomes. As the early research supported both psychological and physiological effects on GWI; current research as summarized in this literature review supports the presence of neuropsychological deficits, particularly in the domains of attention, executive functioning, memory, and motor functioning related to chemical exposures that can be exacerbated by comorbid mood-related conditions. The same test battery has not been used consistently making it difficult to compare results among studies. Therefore, researchers created a resource to provide recommendations for the recently listed Neuropsychological Tests for Common Data Elements (CDEs) for use in all future GWI studies. Future research is necessary to further understand patterns of neuropsychological test data and how these decrements may relate to immunological or other biological markers, and the impact of trauma from physical and psychological stressors. In conclusion, there is consistent evidence that GWI is characterized by neuropsychological decrements - with future research these findings may aid in the diagnosis and assessment of treatment trial efficacy of GW veterans.

Translating Molecular and Neuroendocrine Findings in Posttraumatic Stress Disorder and Resilience to Novel Therapies

Many biological systems are altered in association with posttraumatic stress disorder (PTSD) and resilience. However, there are only few approved pharmacological treatments for PTSD, and no approved medications to enhance resilience. This article provides a critical review of select neurobiological findings in PTSD and resilience, and also of pharmacologic approaches that have emerged from this work. The medications summarized involve engagement with targets in the adrenergic, hypothalamic-pituitary-adrenal axis, and neuropeptide Y systems. Other highlighted approaches involve the use of ketamine and 3,4-methylenedioxymethamphetamine-assisted psychotherapy, which recently surfaced as promising strategies for PTSD, though the neurobiological mechanisms underlying their actions, including for promoting resilience, are not yet fully understood. The former approaches fall within the broad concept of "rational pharmacotherapy," in that they attempt to directly target dysregulated systems known to be associated with posttraumatic symptoms. To the extent that use of ketamine and 3,4-methylenedioxymethamphetamine promotes symptom improvement and resilience in PTSD, this provides an opportunity for reverse translation and identification of relevant targets and mechanisms of action through careful study of biological changes resulting from these interventions. Promoting resilience in trauma-exposed individuals may involve more than pharmacologically manipulating dysregulated molecules and pathways associated with developing and sustaining PTSD symptom severity, but also producing a substantial change in mental state that increases the ability to engage with traumatic material in psychotherapy. Neurobiological examination in the context of treatment studies may yield novel targets and promote a greater understanding of mechanisms of recovery from trauma.

Glucocorticoids and Hippocampal Structure and Function in PTSD

This review examines the putative link between glucocorticoid and hippocampal abnormalities in posttraumatic stress disorder (PTSD). Increased glucocorticoid receptor (GR) sensitivity in PTSD may permit enhanced negative feedback inhibition of cortisol at the pituitary, hypothalamus, or other brain regions comprising the hypothalamic-pituitary-adrenal (HPA) axis and would be expected to affect other physiological systems that are regulated by glucocorticoids. Molecular and transcriptional studies of cortisol are consistent with the hypothesis that cortisol actions may be amplified in PTSD as a result of enhanced GR sensitivity in monocytes and some brain regions, although cortisol levels themselves are unchanged and oftentimes lower than normal. Concurrently, magnetic resonance imaging studies have demonstrated that individuals with PTSD have smaller hippocampal volume than individuals without PTSD. Initial hypotheses regarding the mechanism underlying hippocampal alterations in PTSD focused on elevated glucocorticoid levels in combination with extreme stress as the primary cause, but this explanation has not been well supported in human studies. Lack of data from neuroimaging studies preclude a firm link between PTSD onset and hippocampal volume changes. Rather, the available evidence is consistent with the possibility that smaller hippocampal volume (like reduced cortisol levels and enhanced GR sensitivity) may be a vulnerability factor for developing the disorder; limitations of hippocampal-based models of PTSD are described. We further review neuroimaging studies examining hippocampal structure and function following manipulation of glucocorticoid levels and also examining changes in the hippocampus in relationship to other brain regions. Evidence that the GR may be an important therapeutic target for the treatment of PTSD, especially for functions subserved by the hippocampus, is discussed. Implications of the current review for future research are described, with an emphasis on the need to integrate findings of glucocorticoid abnormalities with functional-imaging paradigms to formulate a comprehensive model of HPA-axis functioning in PTSD.

The hypothalamic-pituitary-adrenal axis in PTSD: Pathophysiology and treatment interventions

Questions of how altered functioning of the hypothalamic pituitary adrenal (HPA) axis contribute to the development and maintenance of posttraumatic stress disorder (PTSD) have been the focus of extensive animal and human research. As a rule, results have been inconsistent across studies, likely due to a variety of confounding variables that have received inadequate attention. Important confounding factors include the effects of early life stress, biological sex, and the glucocorticoid used for interventions. In this manuscript we review: 1) the literature on identified abnormalities of HPA axis function in PTSD, both in terms of basal functioning and as part of challenge paradigms; 2) the role of HPA axis function pre- and immediately post-trauma as a risk factor for PTSD development; 3) the impact of HPA axis genes' allelic variants and epigenetic modifications on PTSD risk; 4) the contributions of HPA axis components to fear learning and extinction; and 5) therapeutic manipulations of the HPA axis to both prevent and treat PTSD, including the role of glucocorticoids as part of medication enhanced psychotherapy.

Neuroendocrinological treatment targets for posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is prevalent, disabling, and frequently becomes chronic. Despite this, only two selective serotonergic reuptake inhibitors have been approved to date for its treatment by the United States Food and Drug Administration, and treatment results are often disappointing, with a remission rate of <30%. Certain neuroendocrinological systems are currently gaining attention with respect to their use for PTSD prevention and treatment as standalone options or medication-enhanced psychotherapy due to their involvement in physiological stress reactions, memory consolidation and extinction, cognitive appraisal to stress, and attachment and resilient coping strategies, which are important in the pathogenesis of PTSD. The hypothalamic-pituitary-adrenal axis system takes the most important role in stress reactions. Hydrocortisone has been studied for the prevention of PTSD, and some meta-analyses have suggested its possible efficacy; furthermore, it has been considered both as monotherapy and as an augmentation to psychotherapy in PTSD patients, with some positive results. Glucocorticoid receptor antagonists and corticotropin-releasing factor type 1 antagonists have also been considered for clinical use in PTSD treatment. Additionally, other neuroendocrinological systems have been studied in PTSD including the use of oxytocin for PTSD prevention and augmentation to psychotherapy, allopregnanolone, and neuropeptide Y (NPY) for PTSD treatment. For now, however, these studies offer only limited evidence of efficacy, thus it is prudent to study this issue more vigorously.

Peripubertal stress-induced heightened aggression: modulation of the glucocorticoid receptor in the central amygdala and normalization by mifepristone treatment

Despite the enormous negative impact of excessive aggression for individuals and societies, there is a paucity of treatments. Here, using a peripubertal stress model of heightened aggression in rats, we investigated the involvement of the glucocorticoid system and tested the effectiveness of antiglucocorticoid treatment to normalize behavior. We assessed peripubertal stress-induced changes in glucocorticoid (GR) and mineralocorticoid (MR) gene expression in different amygdala nuclei and hippocampus, and report a specific increase in GR mRNA expression in the central amygdala (CeA). Administration of mifepristone (10 mg/kg), a GR antagonist, before stressor exposure at peripuberty prevented the habituation of plasma corticosterone responses observed throughout the stress protocol. This treatment also prevented the increase in aggression and GR expression in the CeA observed in peripubertally stressed rats at adulthood. Viral downregulation of CeA GR expression at adulthood led to reduced aggression. Subsequently, we showed that a brief, 3-day, treatment with mifepristone at adulthood was effective to normalize the abnormal aggression phenotype in peripubertally stressed rats. Our results support a key role for GR actions during peripubertal stress for the long-term programming of heightened aggression. Strikingly, they also support the translational interest of testing the effectiveness of mifepristone treatment to diminish reactive aggression in early adversity-related human psychopathologies.

Recent advances in the neurobiology of posttraumatic stress disorder: A review of possible mechanisms underlying an effective pharmacotherapy

Recent progress in the field of neurobiology supported by clinical evidence gradually reveals the mystery of human brain functioning. So far, many psychiatric disorders have been described in great detail, although there are still plenty of cases that are misunderstood. These include posttraumatic stress disorder (PTSD), which is a unique disease that combines a wide range of neurobiological changes, which involve disturbances of the hypothalamic-pituitary-adrenal gland axis, hyperactivation of the amygdala complex, and attenuation of some hippocampal and cortical functions. Such multiplicity results in differential symptomatology, including elevated anxiety, nightmares, fear retrieval episodes that may trigger delusions and hallucinations, sleep disturbances, and many others that strongly interfere with the quality of the patient's life. Because of widespread neurological changes and the disease manifestation, the pharmacotherapy of PTSD remains unclear and requires a multidimensional approach and involvement of polypharmacotherapy. Hopefully, more and more neuroscientists and clinicians will study PTSD, which will provide us with new information that would possibly accelerate establishment of well-tolerated and effective pharmacotherapy. In this review, we have focused on neurobiological changes regarding PTSD, addressing the most disturbed brain structures and neurotransmissions, as well as discussing in detail the recently taken and novel therapeutic paths.

Neuroinflammation and cognition across psychiatric conditions

Cognitive impairments reported across psychiatric conditions (ie, major depressive disorder, bipolar disorder, schizophrenia, and posttraumatic stress disorder) strongly impair the quality of life of patients and the recovery of those conditions. There is therefore a great need for consideration for cognitive dysfunction in the management of psychiatric disorders. The redundant pattern of cognitive impairments across such conditions suggests possible shared mechanisms potentially leading to their development. Here, we review for the first time the possible role of inflammation in cognitive dysfunctions across psychiatric disorders. Raised inflammatory processes (microglia activation and elevated cytokine levels) across diagnoses could therefore disrupt neurobiological mechanisms regulating cognition, including Hebbian and homeostatic plasticity, neurogenesis, neurotrophic factor, the HPA axis, and the kynurenine pathway. This redundant association between elevated inflammation and cognitive alterations across psychiatric disorders hence suggests that a cross-disorder approach using pharmacological and nonpharmacological (ie, physical activity and nutrition) anti-inflammatory/immunomodulatory strategies should be considered in the management of cognition in psychiatry.

Using a Consensus Docking Approach to Predict Adverse Drug Reactions in Combination Drug Therapies for Gulf War Illness

Gulf War Illness (GWI) is a chronic multisymptom illness characterized by fatigue, musculoskeletal pain, and gastrointestinal and cognitive dysfunction believed to stem from chemical exposures during the 1990⁻1991 Persian Gulf War. There are currently no treatments; however, previous studies have predicted a putative multi-intervention treatment composed of inhibiting Th1 immune cytokines followed by inhibition of the glucocorticoid receptor (GCR) to treat GWI. These predictions suggest the use of specific monoclonal antibodies or suramin to target interleukin-2 and tumor necrosis factor α , followed by mifepristone to inhibit the GCR. In addition to this putative treatment strategy, there exist a variety of medications that target GWI symptomatology. As pharmaceuticals are promiscuous molecules, binding to multiple sites beyond their intended targets, leading to off-target interactions, it is key to ensure that none of these medications interfere with the proposed treatment avenue. Here, we used the drug docking programs AutoDock 4.2, AutoDock Vina, and Schrödinger's Glide to assess the potential off-target immune and hormone interactions of 43 FDA-approved drugs commonly used to treat GWI symptoms in order to determine their putative polypharmacology and minimize adverse drug effects in a combined pharmaceutical treatment. Several of these FDA-approved drugs were predicted to be novel binders of immune and hormonal targets, suggesting caution for their use in the proposed GWI treatment strategy symptoms.

High-fidelity discrete modeling of the HPA axis: a study of regulatory plasticity in biology

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) axis is a central regulator of stress response and its dysfunction has been associated with a broad range of complex illnesses including Gulf War Illness (GWI) and Chronic Fatigue Syndrome (CFS). Though classical mathematical approaches have been used to model HPA function in isolation, its broad regulatory interactions with immune and central nervous function are such that the biological fidelity of simulations is undermined by the limited availability of reliable parameter estimates.

METHOD

Here we introduce and apply a generalized discrete formalism to recover multiple stable regulatory programs of the HPA axis using little more than connectivity between physiological components. This simple discrete model captures cyclic attractors such as the circadian rhythm by applying generic constraints to a minimal parameter set; this is distinct from Ordinary Differential Equation (ODE) models, which require broad and precise parameter sets. Parameter tuning is accomplished by decomposition of the overall regulatory network into isolated sub-networks that support cyclic attractors. Network behavior is simulated using a novel asynchronous updating scheme that enforces priority with memory within and between physiological compartments.

RESULTS

Consistent with much more complex conventional models of the HPA axis, this parsimonious framework supports two cyclic attractors, governed by higher and lower levels of cortisol respectively. Importantly, results suggest that stress may remodel the stability landscape of this system, favoring migration from one stable circadian cycle to the other. Access to each regime is dependent on HPA axis tone, captured here by the tunable parameters of the multi-valued logic. Likewise, an idealized glucocorticoid receptor blocker alters the regulatory topology such that maintenance of persistently low cortisol levels is rendered unstable, favoring a return to normal circadian oscillation in both cortisol and glucocorticoid receptor expression.

CONCLUSION

These results emphasize the significance of regulatory connectivity alone and how regulatory plasticity may be explored using simple discrete logic and minimal data compared to conventional methods.

Targeting hypothalamic-pituitary-adrenal axis hormones and sex steroids for improving cognition in major mood disorders and schizophrenia: a systematic review and narrative synthesis

Cognitive deficits are a core feature of serious mental illnesses such as schizophrenia, major depressive disorder (MDD) and bipolar disorder (BD) and are a common cause of functional disability. There is limited efficacy of pharmacological interventions for improving the cognitive deficits in these disorders. As pro-cognitive pharmacological treatments are lacking, hormones or drugs that target the endocrine system may become potential candidates for 'repurposing' trials aiming to improve cognition. We aimed to study whether treatment with drugs targeting the hypothalamic-pituitary-adrenal (HPA) axis and sex steroids can improve cognition in patients with schizophrenia, MDD or BD. A systematic search was performed using PubMed (Medline), PsychInfo and clinicaltrials.gov, and a narrative synthesis was included. The systematic review identified 12 studies dealing with HPA-related drugs (mifepristone [n = 3], cortisol synthesis inhibitors [ketoconazole, n = 2], dehydroepiandrosterone [n = 5], fludrocortisone [n = 2]) and 14 studies dealing with sex steroids (oestradiol [n = 2], selective oestrogen receptor modulators [raloxifene, n = 7], pregnenolone [n = 5]). Positive trials were found for BD (mifepristone), MDD (dehydroepiandrosterone and fludrocortisone) and schizophrenia (dehydroepiandrosterone, raloxifene and pregnenolone). A replication of positive findings by at least two clinical trials was found for mifepristone in BD and raloxifene and pregnenolone in schizophrenia. The use of drugs targeting hormones related to the HPA axis and sex steroids is a promising field of research that might help to improve the cognitive outcome of patients with schizophrenia, bipolar disorder and major depressive disorder in the near future.

Progesterone and human cognition

Progesterone is a neurosteroid and a neuroactive steroid, produced primarily by the corpus luteum and the placenta. In some animal models, progesterone affects cognitive performance, and its potential role in human cognition is especially germane to women. This role can be investigated through associations between peripheral concentrations of progesterone in blood or saliva and neuropsychological test results, through differences in cognitive profiles between women using menopausal hormone therapy with and without a progestogen, and through clinical trials. In naturally cycling reproductive-age women and pregnant women, there is no consistent relation between progesterone levels and cognition. In postmenopausal women within 6 years of menopause and not using hormone therapy, progesterone levels are positively associated with verbal memory and global cognition, but reported associations in older postmenopausal women are null. Some observational studies of postmenopausal women using hormone therapy raise concern of a small deleterious cognitive effect of progestogen (medroxyprogesterone acetate was most often reported in these studies), but this association may due to confounding factors. Small, short-term clinical trials of progesterone show no meaningful effect on cognition. The quality of evidence is low, but overall findings do not reveal consistent, clinically important effects of progesterone on cognitive function in women.

Transcriptional Regulation Involved in Fear Memory Reconsolidation

Memory reconsolidation has been demonstrated to offer a potential target period during which the fear memories underlying fear disorders can be disrupted. Reconsolidation is a labile stage that consolidated memories re-enter after memories are reactivated. Reactivated memories, induced by cues related to traumatic events, are susceptible to strengthening and weakening. Gene transcription regulation and protein synthesis have been suggested to be required for fear memory reconsolidation. Investigating the transcriptional regulation mechanisms underlying reconsolidation may provide a therapeutic method for the treatment of fear disorders such as post-traumatic stress disorder (PTSD). However, the therapeutic effect of treating a fear disorder through interfering with reconsolidation is still contradictory. In this review, we summarize several transcription factors that have been linked to fear memory reconsolidation and propose that transcription factors, as well as related signaling pathways can serve as targets for fear memory interventions. Then, we discuss the application of pharmacological and behavioral interventions during reconsolidation that may or not efficiently treat fear disorders.

Synaptic Loss and the Pathophysiology of PTSD: Implications for Ketamine as a Prototype Novel Therapeutic

PURPOSE OF REVIEW

Studies of the neurobiology and treatment of PTSD have highlighted many aspects of the pathophysiology of this disorder that might be relevant to treatment. The purpose of this review is to highlight the potential clinical importance of an often-neglected consequence of stress models in animals that may be relevant to PTSD: the stress-related loss of synaptic connectivity.

RECENT FINDINGS

Here, we will briefly review evidence that PTSD might be a "synaptic disconnection syndrome" and highlight the importance of this perspective for the emerging therapeutic application of ketamine as a potential rapid-acting treatment for this disorder that may work, in part, by restoring synaptic connectivity. Synaptic disconnection may contribute to the profile of PTSD symptoms that may be targeted by novel pharmacotherapeutics.

Neuroendocrine and neuroimmune markers in PTSD: pre-, peri- and post-trauma glucocorticoid and inflammatory dysregulation

We review current knowledge on how posttraumatic stress disorder (PTSD) is associated with dysregulation of the most commonly studied markers of the endocrine and immune systems pre-, peri- and post-trauma. Lower basal cortisol output, enhanced glucocorticoid receptor function, and a proinflammatory state have been most consistently found in PTSD, with considerable variability among studies and participants. Longitudinal research is scarce, but there is converging evidence that biological dysregulation is present before PTSD onset. Biological dysregulation may become more apparent with increasing time since trauma, and may be reversible with and predict effective treatment. However, considering the variability of findings and the complex interplay of these systems with other factors, the current clinical application of these findings remains limited.

Co-morbidity of PTSD and immune system dysfunction: opportunities for treatment

Posttraumatic stress disorder (PTSD) is defined as a psychiatric disorder; however, PTSD co-occurs with multiple somatic manifestations. People living with PTSD commonly manifest dysregulations in the systems that regulate the stress response, including the hypothalamic-pituitary-adrenal (HPA) axis, and development of a pro-inflammatory state. Additionally, somatic autoimmune and inflammatory diseases and disorders have a high rate of co-morbidity with PTSD. Recognition and understanding of the compounding effect that these disease states can have on each other, evidenced from poorer treatment outcomes and accelerated disease progression in patients suffering from co-morbid PTSD and/or other autoimmune and inflammatory diseases, has the potential to lead to additional treatment opportunities.

New translational perspectives for blood-based biomarkers of PTSD: From glucocorticoid to immune mediators of stress susceptibility

Although biological systems have evolved to promote stress-resilience, there is variation in stress-responses. Understanding the biological basis of such individual differences has implications for understanding Posttraumatic Stress Disorder (PTSD) etiology, which is a maladaptive response to trauma occurring only in a subset of vulnerable individuals. PTSD involves failure to reinstate physiological homeostasis after traumatic events and is due to either intrinsic or trauma-related alterations in physiological systems across the body. Master homeostatic regulators that circulate and operate throughout the organism, such as stress hormones (e.g., glucocorticoids) and immune mediators (e.g., cytokines), are at the crossroads of peripheral and central susceptibility pathways and represent promising functional biomarkers of stress-response and target for novel therapeutics.