Childhood maltreatment and inflammatory markers: a systematic review

Microglia in health and pain: impact of noxious early life events

NEW FINDINGS

What is the topic of this review? This review discusses the origins and development of microglia, and how stress, pain or inflammation in early life disturbs microglial function during critical developmental periods, leading to altered pain sensitivity and/or increased risk of chronic pain in later life. What advances does it highlight? We highlight recent advances in understanding how disrupted microglial function impacts the developing nervous system and the consequences for pain processing and susceptibility for development of chronic pain in later life. The discovery of microglia is accredited to Pío del Río-Hortega, who recognized this 'third element' of CNS cells as being morphologically distinct from neurons and astrocytes. For decades after this finding, microglia were altogether ignored or relegated as simply being support cells. Emerging from virtual obscurity, microglia have now gained notoriety as immune cells that assume a leading role in the development, maintenance and protection of a healthy CNS. Pioneering studies have recently shed light on the origins of microglia, their role in the developing nervous system and the complex roles they play beyond the immune response. These studies reveal that altered microglial function can have a profoundly negative impact on the developing brain and may be a determinant in a range of neurodevelopmental disorders and neurodegenerative diseases. The realization that aberrant microglial function also critically underlies chronic pain, a debilitating disorder that afflicts over 1.5 billion people worldwide, was a major conceptual leap forward in the pain field. Adding to this advance is emerging evidence that early life noxious experiences can have a long-lasting impact on central pain processing and adult pain sensitivity. With microglia now coming of age, in this review we examine the association between adverse early life events, such as stress, injury or inflammation, and the influence of sex differences, on the role of microglia in pain physiology in adulthood.

Neuroimmune Impacts of Early-Life Stress on Development and Psychopathology

Maltreatment and trauma in childhood, termed early-life stress (ELS), has long-term effects on the immune system. ELS impacts immune signaling at the time of exposure but also disrupts the developmental trajectory of certain immunological processes, both in the periphery and in the brain. One consequence of these early alterations is a heightened immune response to stressors later in life. However, chronic and sustained inflammatory response can also lead to excitotoxicity and prevent typical brain development. In this chapter, we discuss current progress toward understanding the contribution of neuroimmune signaling to ELS-attributable dysfunction or maladaptation with a focus on postnatal experiences. To do so we first present an operational definition of ELS. Then, we offer a brief overview of the immune system and neuroimmune development, followed by a section discussing the interaction between immunity, childhood trauma, and mental disorders in humans. We present evidence from animal models about immune alterations after ELS and discuss the ways in which ELS-induced immune changes ultimately affect brain and behavior, as well as the importance of individual differences and future directions in this field. Taken together, we submit that when encountered with ELS, some core brain circuits could develop differently via various mechanisms involving dysfunctional immune reprograming. However, given the remarkable plasticity of both the brain and the immune system, many of the deleterious effects of ELS may be mitigated with interventions that account for sex and target neuroimmune interactions over the lifespan.

Adverse Childhood Experiences and the Consequences on Neurobiological, Psychosocial, and Somatic Conditions Across the Lifespan

Introduction: Adverse childhood experiences (ACE) such as sexual and physical abuse or neglect are frequent in childhood and constitute a massive stressor with long-lasting adverse effects on the brain, mental and physical health.The aim of this qualitative review is to present a concise overview of the present literature on the impact of ACE on neurobiology, mental and somatic health in later adulthood. Methods: The authors reviewed the existing literature on the impact of ACE on neurobiology, mental and somatic health in later adulthood and summarized the results for a concise qualitative overview. Results: In adulthood, the history of ACE can result in complex clinical profiles with several co-occurring mental and somatic disorders such as posttraumatic stress disorder, depression, borderline personality disorder, obesity and diabetes. Although a general stress effect in the development of the disorders and neural alterations can be assumed, the role of type and timing of ACE is of particular interest in terms of prevention and treatment of ACE-related mental and somatic conditions. It has been suggested that during certain vulnerable developmental phases the risk for subsequent ACE-related disorders is increased. Moreover, emerging evidence points to sensitive periods and specificity of ACE-subtypes in the development of neurobiological alterations, e.g., volumetric and functional changes in the amygdala and hippocampus. Conclusion: Longitudinal studies are needed to investigate complex ACE-related characteristics and mechanisms relevant for mental and somatic disorders by integrating state of the art knowledge and methods. By identifying and validating psychosocial and somatic risk factors and diagnostic markers one might improve the development of innovative somatic and psychological treatment options for individuals suffering from ACE-related disorders.

Inflammatory Measures in Depressed Patients With and Without a History of Adverse Childhood Experiences

Background: Major depressive disorder (MDD) is a complex psychiatric condition with different subtypes and etiologies. Exposure to adverse childhood experiences (ACE) is an important risk factor for the development of MDD later in life. Evidence suggests that pro-inflammatory processes may convey this risk as both MDD and ACE have been related to increased levels of inflammation. In the present study, we aimed to disentangle the effects of MDD and ACE on inflammation levels. Methods: Markers of inflammation (plasma interleukin(IL)-6 and high sensitive C-reactive protein (hsCRP) concentrations, white blood cell (WBC) count and a composite inflammation score (CIS) combining all three) were assessed in 23 MDD patients with ACE, 23 MDD patients without ACE, 21 healthy participants with ACE, and 21 healthy participants without ACE (mean age: 35 ± 11 (SD) years). None of the patients and participants was taking psychotropic medication. ACE was assessed with the Early Trauma Inventory (ETI) and was defined as moderate to severe exposure to sexual or physical abuse. Results: Group differences in the different inflammatory measures were observed. MDD patients with ACE showed significantly higher IL-6 concentrations (p = 0.018), higher WBC counts (p = 0.003) and increased general inflammation levels as indicated by the CIS (p = 0.003) compared to healthy controls. In contrast, MDD patients without ACE displayed similar inflammation levels to the control group (p = 0.93). Conclusion: We observed elevated inflammation in MDD patients with a history of ACE, which could indicate a subtype of "inflammatory depression". Accordingly, MDD patients with ACE might potentially benefit from anti-inflammatory therapies.

Adverse Childhood Experiences among a Community of Resilient Centenarians and Seniors: Implications for a Chronic Disease Prevention Framework

CONTEXT

Research has linked adverse childhood experiences (ACEs) with chronic disease in adults and diminished life span. Adverse biological embedding of ACEs potentially occurs through inflammatory mechanisms; inflammatory marker alterations are identified as candidate biomarkers for mediating health consequences. Lifestyle practices of residents of California's Loma Linda Blue Zone, one of five worldwide longevity hotspots, may provide insight into inflammation remediation and chronic disease prevention. Little research has been done on centenarians' early-life experiences or on ACEs in a longevity community.

OBJECTIVE

To interview centenarians and seniors in this region regarding their childhood experiences to inform chronic disease prevention frameworks.

DESIGN

Qualitative study of Loma Linda Blue Zone community members. Childhood exposures and practices were assessed using focus groups and semistructured key informant interviews, with open-ended questions on general hardships and ACEs and supplemented with lifestyle and resiliency factor questions. Data were audiorecorded and transcribed. Integrative grounded theory methods guided coding and theming.

MAIN OUTCOME MEASURES

Exposure to ACEs and practice of resiliency factors.

RESULTS

Participants (7 centenarians and 29 seniors) reported exposure to multiple ACEs (domains: Economic deprivation, family dysfunction, and community violence). Community members reported practicing resiliency factors, each with anti-inflammatory properties suggesting mitigation of ACE-related toxic stress.

CONCLUSION

This is one of the first studies of its kind to identify a community of resilient members despite their tremendous burden of ACEs. Embedding the identified resiliency factors into chronic disease prevention frameworks has potential for mitigating systemic inflammation, alleviating chronic disease burden, and promoting a culture of health.

Effects of early-life adversity on immune function are mediated by prenatal environment: Role of prenatal alcohol exposure

The contribution of the early postnatal environment to the pervasive effects of prenatal alcohol exposure (PAE) is poorly understood. Moreover, PAE often carries increased risk of exposure to adversity/stress during early life. Dysregulation of immune function may play a role in how pre- and/or postnatal adversity/stress alters brain development. Here, we combine two animal models to examine whether PAE differentially increases vulnerability to immune dysregulation in response to early-life adversity. PAE and control litters were exposed to either limited bedding (postnatal day [PN] 8-12) to model early-life adversity or normal bedding, and maternal behavior and pup vocalizations were recorded. Peripheral (serum) and central (amygdala) immune (cytokines and C-reactive protein - CRP) responses of PAE animals to early-life adversity were evaluated at PN12. Insufficient bedding increased negative maternal behavior in both groups. Early-life adversity increased vocalization in all animals; however, PAE pups vocalized less than controls. Early-life adversity reduced serum TNF-α, KC/GRO, and IL-10 levels in control but not PAE animals. PAE increased serum CRP, and levels were even higher in pups exposed to adversity. Finally, PAE reduced KC/GRO and increased IL-10 levels in the amygdala. Our results indicate that PAE alters immune system development and both behavioral and immune responses to early-life adversity, which could have subsequent consequences for brain development and later life health.

Evidence for Immune Activation and Resistance to Glucocorticoids Following Childhood Maltreatment in Adolescents Without Psychopathology

Early-life stress (ELS) increases the risk for psychopathology. Immune and endocrine changes have been reported in adults and are associated with maladaptation of stress-responsive systems. Here we investigated the effects of ELS on endocrine and immune pathways in adolescents without psychopathology. Thirty adolescents with a history of childhood maltreatment and 27 adolescents without ELS history were recruited. Blood and hair samples were obtained from all participants. Lymphocytes were isolated and stimulated in vitro. Flow cytometry was used to evaluate lymphocyte subsets, Th1/Th2/Th17 cytokines, mitogen-activated protein kinase (MAPK), and nuclear factor kappa B (NF-κB) signaling pathways, as well as lymphocyte sensitivity to dexamethasone. Brain-derived neurotrophic factor (BDNF) and hair cortisol were assessed with enzyme-linked immunosorbent assays (ELISAs). Adolescents with a history of ELS had increased percentages of T-cell activation markers (CD3+CD4+CD25+ and CD3+CD69+) and senescent T cells (CD8+CD28- and CD4+CD28-), as well as decreased percentages of NK (CD3-CD56+) and NK T cells (CD3+CD56+). Following stimulation, lymphocytes of ELS+ adolescents produced significantly more IL-2, IL-4, IFN-γ, and IL-17 and engaged more MAPK ERK and NF-κB signaling. ELS was associated with increased hair cortisol levels in parallel with increased lymphocyte resistance to dexamethasone and low plasma BDNF levels. These data provide the first indication of the presence of immune activation and pro-inflammatory profiles in healthy adolescents exposed to ELS, which could contribute to increased vulnerability of trauma-related psychopathology later in life. The underlying mechanisms of this impairment may include the enhanced activation of both MAPK and NF-κB signaling in parallel to partial resistance to glucocorticoids.

Childhood maltreatment severity is associated with elevated C-reactive protein and body mass index in adults with schizophrenia and bipolar diagnoses

BACKGROUND

Several studies have described an association between childhood maltreatment and inflammatory markers in the psychotic disorders (schizophrenia [SZ] and bipolar disorder [BD]). Previous studies have been relatively small (<50 participants), and the severity of abuse and the putative influence of body mass index (BMI) have not been properly investigated.

METHODS

The combined effects of childhood abuse severity and clinical diagnosis on inflammatory markers were investigated in a large sample (n=483) of patients with a disorder on the psychosis spectrum and in healthy controls (HCs). Plasma levels of inflammatory markers (high-sensitivity C-reactive protein [hs-CRP], soluble tumor necrosis factor receptor type 1 [TNFR-R1], glycoprotein 130 [gp130]) were analyzed, and BMI and data on childhood trauma events, on the basis of the Childhood Trauma Questionnaire (CTQ), were obtained from all participants.

RESULTS

Patients had increased levels of hs-CRP (P<0.001, Cohens d=0.4), lower levels of gp130 (P<0.001, Cohens d=0.5), higher BMI (P<0.001, Cohens d=0.5) and reported more childhood maltreatment experiences (P<0.001, Cohens d=1.2) than the HC group. The severity of childhood abuse (up to three types of abuse: sexual abuse, physical abuse, and emotional abuse) was associated with elevated BMI (f=8.46, P<0.001, Cohen's d=0.5) and hs-CRP (f=5.47, P=0.001, Cohen's d=0.3). Combined effects of patient status and severity of childhood abuse were found for elevated hs-CRP (f=4.76, P<0.001, Cohen's d=0.4). Differences among the groups disappeared when BMI was added to the model.

DISCUSSION

Trauma-altered immune activation via elevated hs-CRP in patients with SZ and BD may be mediated by higher BMI; however, the direction of this association needs further clarification.

Relationship between infant malnutrition and childhood maltreatment in a Barbados lifespan cohort

Childhood malnutrition and maltreatment (abuse, neglect) are both prevalent, particularly in resource-limited settings. Despite their known negative impact on child development, there is surprisingly little research documenting their interrelationships. To address this gap, we administered the Childhood Trauma Questionnaire-Short Form (CTQ-SF), a retrospective structured self-report of childhood abuse and neglect, in a Barbadian cohort of 77 adult survivors of infant malnutrition, limited to the first year of life, and 62 healthy controls from the same classrooms and neighborhoods (mean age ± SD = 43.8±2.3 years). This cohort has been followed since birth. Using factor analysis and comparison with archival data addressing similar constructs, we found evidence for reliability and validity of the CTQ-SF in this population. Linear regression analyses, with and without adjusting for childhood household standard of living at three childhood ages, revealed that a history of infant malnutrition was significantly associated with increased levels of self-reported physical neglect in childhood, and, to a somewhat lesser degree, emotional neglect. This study highlights the co-occurrence of infant malnutrition and self-reported maltreatment in childhood in Barbados, with potential public health implications.

Developmental psychoneuroendocrine and psychoneuroimmune pathways from childhood adversity to disease

Childhood adversity has been repeatedly and robustly linked to physical and mental illness across the lifespan. Yet, the biological pathways through which this occurs remain unclear. Functioning of the inflammatory arm of the immune system and the hypothalamic-pituitary-adrenal (HPA)-axis are both hypothesized pathways through which childhood adversity leads to disease. This review provides a novel developmental framework for examining the role of adversity type and timing in inflammatory and HPA-axis functioning. In particular, we identify elements of childhood adversity that are salient to the developing organism: physical threat, disrupted caregiving, and unpredictable environmental conditions. We propose that existing, well-characterized animal models may be useful in differentiating the effects of these adversity elements and review both the animal and human literature that supports these ideas. To support these hypotheses, we also provide a detailed description of the development and structure of both the HPA-axis and the inflammatory arm of the immune system, as well as recent methodological advances in their measurement. Recommendations for future basic, developmental, translational, and clinical research are discussed.

Towards an Integrated View of Early Molecular Changes Underlying Vulnerability to Social Stress in Psychosis

Psychotic disorders are heterogeneous and complex, involving many putative causal factors interacting along the course of disease development. Many of the factors implicated in the pathogenesis of psychosis also appear to be involved in disease onset and subsequent neuroprogression. Herein, we highlight the pertinent literature implicating inflammation and oxidative stress in the pathogenesis of psychosis, and the potential contribution of N-methyl-D-aspartate receptors (NMDARs). We also emphasize the role of peripubertal social stress in psychosis, and the ways in which hippocampal dysfunction can mediate dysregulation of the hypothalamic-pituitary-adrenal axis and cortisol release. Finally, we propose a model wherein inflammation and oxidative stress act as a first hit, producing altered parvalbumin interneuron development, NMDAR hypofunction, microglial priming, and sensitivity to a second hit of peripubertal social stress. With a greater understanding of how these factors interact, it may be possible to detect, prevent, and treat psychosis more effectively.

Early-life stress lastingly alters the neuroinflammatory response to amyloid pathology in an Alzheimer's disease mouse model

Exposure to stress during the sensitive period of early-life increases the risk to develop cognitive impairments and psychopathology later in life. In addition, early-life stress (ES) exposure, next to genetic causes, has been proposed to modulate the development and progression of Alzheimer's disease (AD), however evidence for this hypothesis is currently lacking. We here tested whether ES modulates progression of AD-related neuropathology and assessed the possible contribution of neuroinflammatory factors in this. We subjected wild-type (WT) and transgenic APP/PS1 mice, as a model for amyloid neuropathology, to chronic ES from postnatal day (P)2 to P9. We next studied how ES exposure affected; 1) amyloid β (Aβ) pathology at an early (4month old) and at a more advanced pathological (10month old) stage, 2) neuroinflammatory mediators immediately after ES exposure as well as in adult WT mice, and 3) the neuroinflammatory response in relation to Aβ neuropathology. ES exposure resulted in a reduction of cell-associated amyloid in 4month old APP/PS1 mice, but in an exacerbation of Aβ plaque load at 10months of age, demonstrating that ES affects Aβ load in the hippocampus in an age-dependent manner. Interestingly, ES modulated various neuroinflammatory mediators in the hippocampus of WT mice as well as in response to Aβ neuropathology. In WT mice, immediately following ES exposure (P9), Iba1-immunopositive microglia exhibited reduced complexity and hippocampal interleukin (IL)-1β expression was increased. In contrast, microglial Iba1 and CD68 were increased and hippocampal IL-6 expression was decreased at 4months, while these changes resolved by 10months of age. Finally, Aβ neuropathology triggered a neuroinflammatory response in APP/PS1 mice that was altered after ES exposure. APP/PS1 mice exhibited increased CD68 expression at 4months, which was further enhanced by ES, whereas the microglial response to Aβ neuropathology, as measured by Iba1 and CD11b, was less prominent after ES at 10months of age. Finally, the hippocampus appears to be more vulnerable for these ES-induced effects, since ES did not affect Aβ neuropathology and neuroinflammation in the entorhinal cortex of adult ES exposed mice. Overall, our results demonstrate that ES exposure has both immediate and lasting effects on the neuroinflammatory response. In the context of AD, such alterations in neuroinflammation might contribute to aggravated neuropathology in ES exposed mice, hence altering disease progression. This indicates that, at least in a genetic context, ES could aggravate AD pathology.

Neurobiological Development in the Context of Childhood Trauma

Neurobiological systems may be particularly susceptible to deleterious impact of childhood trauma, and the impact of childhood trauma on development and subsequent functional outcomes across the lifespan has been well-documented. The current review addresses the neurobiological impact of exposure to interpersonal trauma in childhood in the context of executive function, emotion regulation, and dissociation/interoceptive awareness. Subsequent risk for PTSD and depression is also discussed. The pathway of risk from childhood trauma to these cognitive, emotional, and psychiatric outcomes is addressed in terms of potential structural and functional alterations within the hippocampus, prefrontal cortex, and amygdala resulting from chronic or repeated activation of the hypothalamic-pituitary-adrenal (HPA) axis and its interaction with and influence on genetic and epigenetic processes during sensitive periods of development. Implications for practice are discussed.

Childhood maltreatment and inflammation among pregnant women with gestational diabetes mellitus: A pilot study

BACKGROUND

Women with childhood maltreatment histories are at increased risk for adverse birth outcomes. Mechanisms explaining this link are poorly understood. Past research is limited by sampling pregnant women at low risk for adverse maternal and neonatal outcomes.

METHODS

This pilot study was a secondary data analysis of 24 women with gestational diabetes mellitus; 17% of the sample also reported a maltreatment history. Women provided a blood sample to measure inflammatory cytokines and insulin resistance, and saliva samples to measure diurnal cortisol. Birth outcomes for past and current pregnancies were recorded.

RESULTS

Histories of maltreatment were associated with elevated interleukin-15 and a marginally greater incidence of preterm delivery in current and past pregnancies.

CONCLUSIONS

This pilot study was the first to demonstrate an association between childhood maltreatment history and inflammatory cytokine levels in pregnant women diagnosed with gestational diabetes mellitus.

Childhood trauma and mixed episodes are associated with poor response to lithium in bipolar disorders

OBJECTIVES

Reliable predictors of response to lithium are still lacking in bipolar disorders (BDs). However, childhood trauma has been hypothesized to be associated with poor response to lithium.

METHODS

We included 148 patients with BD, euthymic when retrospectively and clinically assessed for response to lithium and childhood trauma using reliable scales.

RESULTS

According to the 'Alda scale', the sample consisted in 20.3% of excellent responders, 49.3% of partial responders and 30.4% of non-responders to lithium. A higher level of physical abuse significantly correlated with a lower level of response to lithium (P = 0.009). As compared to patients not exposed to any abuse, patients with at least two trauma abuses (emotional, physical or sexual) were more at risk of belonging to the non-responders group (OR = 4.91 95% CI (1.01-27.02)). Among investigated clinical variables, lifetime presence of mixed episodes and alcohol misuse were associated with non-response to lithium. Multivariate analyses demonstrated that physical abuse and mixed episodes were independently associated with poor response to lithium (P = 0.005 and P = 0.013 respectively).

CONCLUSIONS

Childhood physical abuse might be involved in a poor future response to lithium prophylaxis, this effect being independent of the association between clinical expression of BD and poor response to lithium.

Harm avoidance and childhood adversities in patients with obsessive-compulsive disorder and their unaffected first-degree relatives

OBJECTIVE

The etiology of obsessive-compulsive disorder (OCD) is assumed to involve interactions between genetically determined vulnerability factors and significant environmental features. Here, we aim to investigate how the personality trait harm avoidance and the experience of childhood adversities contribute to OCD.

METHOD

A total of 169 patients with OCD, 157 healthy comparison subjects, and 57 unaffected first-degree relatives of patients with OCD participated in the study. Harm avoidance was assessed using the Temperament and Character Inventory, and the severity of childhood adversities was measured with the Childhood Trauma Questionnaire.

RESULTS

Both patients with OCD and relatives showed elevated levels of harm avoidance compared to controls. Furthermore, patients exhibited significantly higher scores than relatives. This linear pattern was observed throughout all subscales of harm avoidance, and remained stable after controlling for the severity of depressive and obsessive-compulsive symptoms. With regard to childhood adversities, patients with OCD reported higher levels than relatives and controls.

CONCLUSION

Our results provide further evidence for a diathesis-stress model of OCD. While patients and unaffected relatives share elevated levels of harm avoidance, supporting the role of harm avoidance as an endophenotype of OCD, a heightened severity of childhood adversity was only observed in patients. The assumed biological underpinnings of these findings are discussed.

Depressive-like behavior, its sensitization, social buffering, and altered cytokine responses in rhesus macaques moved from outdoor social groups to indoor housing

Psychosocial stressors appear to promote the onset of depressive illness through activation and sensitization of inflammatory mechanisms. Here, adult male rhesus monkeys brought from large outdoor social groups to indoor housing for 8 days reliably exhibited a hunched, depressive-like posture. When rehoused indoors a second 8 days about 2 weeks later, monkeys housed alone, but not those with an affiliative partner, showed sensitization of the depressive-like hunched posture. Housing indoors also affected circulating pro-inflammatory cytokines: IL-1β showed increased responsiveness to immune challenge, and IL-1β and TNF-α showed reduced suppression by dexamethasone. Sensitivity of the anti-inflammatory cytokine IL-10 to immune challenge exhibited a relative increase from the first to the second round of indoor housing in animals housed in pairs, and a relative decrease in animals housed alone. Cytokine levels during indoor housing were positively correlated with duration of depressive-like behavior. Plasma cortisol levels increased but did not differentiate housing conditions or rounds. Results demonstrate a rapid induction and sensitization of depressive-like behavior to indoor individual housing, social buffering of sensitization, and associated inflammatory responses. This paradigm may provide a practical nonhuman primate model for examining inflammatory-mediated consequences of psychosocial stressors on depression and possible social buffering of these effects.

Transcriptomic analyses and leukocyte telomere length measurement in subjects exposed to severe recent stressful life events

Stressful life events occurring in adulthood have been found able to affect mood and behavior, thus increasing the vulnerability for several stress-related psychiatric disorders. However, although there is plenty of clinical data supporting an association between stressful life events in adulthood and an enhanced vulnerability for psychopathology, the underlying molecular mechanisms are still poorly investigated. Thus, in this study we performed peripheral/whole-genome transcriptomic analyses in blood samples obtained from 53 adult subjects characterized for recent stressful life events occurred within the previous 6 months. Transcriptomic data were analyzed using Partek Genomics Suite; pathway and network analyses were performed using Ingenuity Pathway Analysis and GeneMANIA Software. We found 207 genes significantly differentially expressed in adult subjects who reported recent stressful life experiences (n=21) compared with those without such experiences (n=32). Moreover, the same subjects exposed to such stressful experiences showed a reduction in leukocyte telomere length. A correlation analyses between telomere length and transcriptomic data indicated an association between the exposures to recent stressful life events and the modulation of several pathways, mainly involved in immune-inflammatory-related processes and oxidative stress, such as natural killer cell signaling, interleukin-1 (IL-1) signaling, MIF regulation of innate immunity and IL-6 signaling. Our data suggest an association between exposures to recent stressful life events in adulthood and alterations in the immune, inflammatory and oxidative stress pathways, which could be also involved in the negative effect of stressful life events on leukocyte telomere length. The modulation of these mechanisms may underlie the clinical association between the exposure to recent Stressful life events in adulthood and an enhanced vulnerability to develop psychiatric diseases in adulthood.

Future Directions in the Study of Early-Life Stress and Physical and Emotional Health: Implications of the Neuroimmune Network Hypothesis

Early-life stress is associated with increased vulnerability to physical and emotional health problems across the lifespan. The recently developed neuroimmune network hypothesis proposes that one of the underlying mechanisms for these associations is that early-life stress amplifies bidirectional crosstalk between the brain and the immune system, contributing to several mental and physical health conditions that have inflammatory underpinnings, such as depression and coronary heart disease. Neuroimmune crosstalk is thought to perpetuate inflammation and neural alterations linked to early-life stress exposure, and also foster behaviors that can further compromise health, such as smoking, drug abuse and consumption of high-fat diets. The goal of the present review is to briefly summarize the neuroimmune network hypothesis and use it as a starting point for generating new questions about the role of early-life stress in establishing a dysregulated relationship between neural and immune signaling, with consequences for lifespan physical and emotional health. Specifically, we aim to discuss implications and future directions for theory and empirical research on early-life stress, as well as for interventions that may improve the health and well-being of children and adolescents living in adverse conditions.

The association between parental separation during childhood and obesity in adulthood: a Danish twin study

Objective

The purpose of this study was to examine if parental separation during childhood is associated with obesity in adulthood.

Methods

A co‐twin case–control study of 146 adult same‐sexed twin pairs with discordant body mass index (BMI) (i.e. one of the twins should have a BMI of 20–25 kg/m², and the co‐twin's BMI ≥ 30 kg/m²) was selected from Danish Twin Registry (DTR). In total of 236 eligible twin individuals participated in the study. Childhood parental separation (defined as separation from one of the biological parents, regardless of the reason for separation) for at least one year prior to age 17 was self‐reported. The statistical analysis includes logistic and linear regression models using STATA 13.0.

Results

There were no differences in the odds of developing obesity in adulthood between the twin who stayed with a father and the co‐twin who was separated from him for at least 1 year prior to age 17 [OR = 1.22, 95%CI (0.46–3.34), p = 0.65]. Separation from a mother also showed no differences in the odds for developing obesity [OR = 0.90, 95%CI (0.32–2.46), p = 0.82].

Conclusions

Because of the limited number of discordant twin pairs for childhood parental separation, we cannot provide evidence to suggest that separation from parents in childhood was associated with developing obesity in adulthood. Further studies of pooling discordant twins from several countries should be considered.

Frontal brain asymmetry, childhood maltreatment, and low-grade inflammation at midlife

Frontal EEG asymmetry is thought to reflect variations in affective style, such that greater relative right frontal activity at rest predicts enhanced emotional responding to threatening or negative stimuli, and risk of depression and anxiety disorders. A diathesis-stress model has been proposed to explain how this neuro-affective style might predispose to psychopathology, with greater right frontal activity being a vulnerability factor especially under stressful conditions. Less is known about the extent to which greater relative right frontal activity at rest might be associated with or be a diathesis for deleterious physical health outcomes. The present study examined the association between resting frontal EEG asymmetry and systemic, low-grade inflammation and tested the diathesis-stress model by examining whether childhood maltreatment exposure interacts with resting frontal asymmetry in explaining inflammation. Resting EEG, serum inflammatory biomarkers (interleukin-6, C-reactive protein, and fibrinogen) and self-reported psychological measures were available for 314 middle-aged adults (age M=55.3years, SD=11.2, 55.7% female). Analyses supported the diathesis-stress model and revealed that resting frontal EEG asymmetry was significantly associated with inflammation, but only in individuals who had experienced moderate to severe levels of childhood maltreatment. These findings suggest that, in the context of severe adversity, a trait-like tendency towards greater relative right prefrontal activity may predispose to low-grade inflammation, a risk factor for conditions with inflammatory underpinnings such as coronary heart disease.

Childhood Maltreatment Is an Independent Risk Factor for Prediabetic Disturbances in Glucose Regulation

AIMS

Childhood maltreatment (CM) is shown to be associated with obesity and depression. However, the relationship of CM to prediabetic state is much less studied. We tested the hypothesis that CM increases the risk for prediabetic state due to glucose intolerance, reduced insulin sensitivity, and beta cell function.

METHODS

Oral glucose tolerance test (OGTT)-derived metabolic parameters of glucose tolerance, insulin sensitivity, and beta cell function were measured in 121 participants aged 19-60 years. CM exposure was measured using the Childhood Trauma Questionnaire. Blood samples were collected to measure the inflammatory factors.

RESULTS

After controlling for age, race, gender, education, and depression, about 15% higher glucose area under the OGTT curve was observed in the CM group. CM individuals also exhibited impaired insulin sensitivity manifested by the Matsuda index and homeostasis model assessment of insulin resistance, which were correlated with CM severity after adjusting for depression. CM group showed approximately 50% lower disposition index. C-reactive protein and tumor necrosis factor-α levels were greater in the CM group vs. the non-CM group, and both were correlated with CM severity (r = 0.21, 0.23, respectively, both p < 0.05). Multiple regression analyses revealed that CM contributed to reduced insulin sensitivity and lower disposition index independent of depression and visceral fat mass.

CONCLUSION

These data suggest an important relationship between CM and increased risk for prediabetic state due to glucose intolerance, impaired insulin sensitivity, and beta cell function. Our findings indicate that CM appears to be an independent risk factor for developing prediabetes.

Psychoneuroimmunology of Early-Life Stress: The Hidden Wounds of Childhood Trauma?

The brain and the immune system are not fully formed at birth, but rather continue to mature in response to the postnatal environment. The two-way interaction between the brain and the immune system makes it possible for childhood psychosocial stressors to affect immune system development, which in turn can affect brain development and its long-term functioning. Drawing from experimental animal models and observational human studies, we propose that the psychoneuroimmunology of early-life stress can offer an innovative framework to understand and treat psychopathology linked to childhood trauma. Early-life stress predicts later inflammation, and there are striking analogies between the neurobiological correlates of early-life stress and of inflammation. Furthermore, there are overlapping trans-diagnostic patterns of association of childhood trauma and inflammation with clinical outcomes. These findings suggest new strategies to remediate the effect of childhood trauma before the onset of clinical symptoms, such as anti-inflammatory interventions and potentiation of adaptive immunity. Similar strategies might be used to ameliorate the unfavorable treatment response described in psychiatric patients with a history of childhood trauma.

Tumor necrosis factor-alpha expression in peripheral blood mononuclear cells correlates with early childhood social interaction in autism spectrum disorder

Autism spectrum disorder is a neurodevelopmental disorder characterized by impaired social interaction, poor communication skills, and repetitive/restrictive behaviors. Elevated blood levels of pro-inflammatory cytokines have been reported in subjects with autism spectrum disorder. On the other hand, early childhood adverse experience also increases blood levels of these cytokines. Since social experience of children with autism spectrum disorder is generally unlike to typically developing children, we hypothesized that social interaction during childhood contribute to pro-inflammatory cytokine expression in subjects with autism spectrum disorder. We compared revised Autism Diagnostic Interview scores and expression levels of pro-inflammatory cytokines in peripheral blood mononuclear cells of subjects with autism spectrum disorder (n = 30). The score of domain A on the revised Autism Diagnostic Interview, indicating social interaction impairment in early childhood, was negatively correlated with tumor necrosis factor-α mRNA expression level in peripheral blood mononuclear cells but not interleukin-1β or -6. Consistently, tumor necrosis factor-α mRNA expression was markedly low in subjects with autism spectrum disorder compared to typically developing children who presumably experienced the regular levels of social interaction. These findings suggest that the low blood levels of tumor necrosis factor-α mRNA in subjects with autism spectrum disorder might be due to impaired social interaction in early childhood.

Interleukin-1 β-targeted treatment strategies in inflammatory depression: toward personalized care

OBJECTIVES

It is unknown whether a cytokine signature may help the identification of subgroup of patient who would respond to personalized treatment. As interleukin-1 beta (Il-1β) seems to play a major role in mood disorder, a systematic review and meta-analysis of its potential role in major depressive disorder (MDD) was carried out.

METHODS

A systematic search was performed to identify appropriate MDD vs. control studies pertaining to Il-1β. Methodological quality and possible moderators were also assessed.

RESULTS

A total of 1922 studies were identified, and 53 articles were selected. Results showed an association between increased blood IL-1β and MDD in high-quality studies only. No association with age was found. No IL-1β gene-related polymorphisms has been associated with MDD. No effect of antidepressant on IL-1β level has been found, although the antidepressants investigated were various. Qualitative analyses indicate that MDD coupled to a history of childhood trauma may be a subgroup for IL-1β -targeted therapies. No difference in studies utilizing a stimulation method has been identified to date.

CONCLUSIONS

The present work has confirmed IL-1β as a biological marker of interest for innovative MDD treatments. However, further studies are needed to clarify the patients with MDD who may benefit from these therapies.

Depression in cancer: The many biobehavioral pathways driving tumor progression

Major Depressive Disorder (MDD) is common among cancer patients, with prevalence rates up to four-times higher than the general population. Depression confers worse outcomes, including non-adherence to treatment and increased mortality in the oncology setting. Advances in the understanding of neurobiological underpinnings of depression have revealed shared biobehavioral mechanisms may contribute to cancer progression. Moreover, psychosocial stressors in cancer promote: (1) inflammation and oxidative/nitrosative stress; (2) a decreased immunosurveillance; and (3) a dysfunctional activation of the autonomic nervous system and of the hypothalamic-pituitaryadrenal axis. Consequently, the prompt recognition of depression among patients with cancer who may benefit of treatment strategies targeting depressive symptoms, cognitive dysfunction, fatigue and sleep disturbances, is a public health priority. Moreover, behavioral strategies aiming at reducing psychological distress and depressive symptoms, including addressing unhealthy diet and life-style choices, as well as physical inactivity and sleep dysfunction, may represent important strategies not only to treat depression, but also to improve wider cancer-related outcomes. Herein, we provide a comprehensive review of the intertwined biobehavioral pathways linking depression to cancer progression. In addition, the clinical implications of these findings are critically reviewed.

Cytokine levels in major depression are related to childhood trauma but not to recent stressors

BACKGROUND

Major depressive disorder (MDD) is a stress-related psychiatric disorder. A subgroup of MDD patients is characterized by increased inflammatory activation. We aimed to investigate whether increased inflammation particularly occurs in MDD patients with a history of stressful early or later life experiences.

METHODS

Serum levels of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6 were determined in N=214 MDD patients and N=180 healthy controls (HC). Childhood trauma (Childhood Trauma Questionnaire - CTQ), adverse life events of the past 12 months (List of Threatening Experiences Questionnaire - LTE-Q), and perceived stress in the past month (Perceived Stress Scale - PSS) were analyzed with regard to cytokine levels.

RESULTS

Pro-inflammatory cytokine levels were not related to global scores of adverse events or perceived stress covering different time points ranging from childhood to the past month. However, in the subgroup of traumatized MDD patients, higher severity of childhood sexual abuse was associated with higher levels of both IL-6 and TNF-α in a linear fashion.

CONCLUSIONS

Our data suggest a linear relationship between childhood sexual abuse and increased pro-inflammatory cytokine levels in MDD patients, while more recent stressful life events were not related to these inflammatory markers.

Effect of childhood maltreatment and brain-derived neurotrophic factor on brain morphology

Childhood maltreatment (CM) has been associated with altered brain morphology, which may partly be due to a direct impact on neural growth, e.g. through the brain-derived neurotrophic factor (BDNF) pathway. Findings on CM, BDNF and brain volume are inconsistent and have never accounted for the entire BDNF pathway. We examined the effects of CM, BDNF (genotype, gene expression and protein level) and their interactions on hippocampus, amygdala and anterior cingulate cortex (ACC) morphology. Data were collected from patients with depression and/or an anxiety disorder and healthy subjects within the Netherlands Study of Depression and Anxiety (NESDA) (N = 289). CM was assessed using the Childhood Trauma Interview. BDNF Val66Met genotype, gene expression and serum protein levels were determined in blood and T1 MRI scans were acquired at 3T. Regional brain morphology was assessed using FreeSurfer. Covariate-adjusted linear regression analyses were performed. Amygdala volume was lower in maltreated individuals. This was more pronounced in maltreated met-allele carriers. The expected positive relationship between BDNF gene expression and volume of the amygdala is attenuated in maltreated subjects. Finally, decreased cortical thickness of the ACC was identified in maltreated subjects with the val/val genotype. CM was associated with altered brain morphology, partly in interaction with multiple levels of the BNDF pathway. Our results suggest that CM has different effects on brain morphology in met-carriers and val-homozygotes and that CM may disrupt the neuroprotective effect of BDNF.

Differential DNA methylation in peripheral blood mononuclear cells in adolescents exposed to significant early but not later childhood adversity

Internationally adopted adolescents who are adopted as young children from conditions of poverty and deprivation have poorer physical and mental health outcomes than do adolescents conceived, born, and raised in the United States by families similar to those who adopt internationally. Using a sample of Russian and Eastern European adoptees to control for Caucasian race and US birth, and nonadopted offspring of well-educated and well-resourced parents to control for postadoption conditions, we hypothesized that the important differences in environments, conception to adoption, might be reflected in epigenetic patterns between groups, specifically in DNA methylation. Thus, we conducted an epigenome-wide association study to compare DNA methylation profiles at approximately 416,000 individual CpG loci from peripheral blood mononuclear cells of 50 adopted youth and 33 nonadopted youth. Adopted youth averaged 22 months at adoption, and both groups averaged 15 years at testing; thus, roughly 80% of their lives were lived in similar circumstances. Although concurrent physical health did not differ, cell-type composition predicted using the DNA methylation data revealed a striking difference in the white blood cell-type composition of the adopted and nonadopted youth. After correcting for cell type and removing invariant probes, 30 CpG sites in 19 genes were more methylated in the adopted group. We also used an exploratory functional analysis that revealed that 223 gene ontology terms, clustered in neural and developmental categories, were significantly enriched between groups.

Prenatal maternal depression is associated with offspring inflammation at 25 years: a prospective longitudinal cohort study

Animal studies and a handful of prospective human studies have demonstrated that young offspring exposed to maternal prenatal stress show abnormalities in immune parameters and hypothalamic-pituitary-adrenal (HPA) axis function. No study has examined the effect of maternal prenatal depression on offspring inflammation and HPA axis activity in adulthood, nor the putative role of child maltreatment in inducing these abnormalities. High-sensitivity C-reactive protein (hs-CRP) and awakening cortisol were measured at age 25 in 103 young-adult offspring of the South London Child Development Study (SLCDS), a prospective longitudinal birth cohort of mother-offspring dyads recruited in pregnancy in 1986. Maternal prenatal depression was assessed in pregnancy at 20 and 36 weeks; offspring child maltreatment (birth 17 years) was assessed at offspring ages 11, 16 and 25; and offspring adulthood depression (18-25 years) was assessed at age 25. Exposure to maternal prenatal depression predicted significantly elevated offspring hs-CRP at age 25 (odds ratio=11.8, 95% confidence interval (CI) (1.1, 127.0), P=0.041), independently of child maltreatment and adulthood depression, known risk factors for adulthood inflammation. In contrast, maternal prenatal depression did not predict changes in offspring adulthood cortisol; however, offspring exposure to child maltreatment did, and was associated with elevated awakening cortisol levels (B=161.9, 95% CI (45.4, 278.4), P=0.007). Fetal exposure to maternal depression during pregnancy has effects on immune function that persist for up to a quarter of a century after birth. Findings are consistent with the developmental origins of health and disease (DOHaD) hypothesis for the biological embedding of gestational psychosocial adversity into vulnerability for future physical and mental illness.

Immuno-psychiatry: an agenda for clinical practice and innovative research

BACKGROUND

The diagnostic scheme for psychiatric disorders is currently based purely on descriptive nomenclature given that biomarkers subtypes and clearly defined causal mechanisms are lacking for the vast majority of disorders. The emerging field of "immuno-psychiatry" has the potential to widen the exploration of a mechanism-based nosology, possibly leading to the discovery of more effective personalised treatment strategies.

DISCUSSION

Disturbances in immuno-inflammatory and related systems have been implicated in the aetiology, pathophysiology, phenomenology and comorbidity of several psychiatric disorders, including major mood disorders and schizophrenia. A fundamental challenge in their clinical management is to identify bio-signatures that might indicate risk, state, trait, prognosis or theragnosis. Here, we provide the rationale for a clinical and research agenda to refine future clinical practice and conceptual views, and to delineate pathways toward innovative treatment discovery.

CONCLUSION

The development of bio-signatures will allow clinicians to tailor interventions to the abovementioned biomarker subtypes - a major translational goal for research in this field.

Early life stress perturbs the maturation of microglia in the developing hippocampus

Children exposed to abuse or neglect show abnormal hippocampal development and similar findings have been reported in rodent models. Using brief daily separation (BDS), a mouse model of early life stress, we previously showed that exposure to BDS impairs hippocampal function in adulthood and perturbs synaptic maturation, synaptic pruning, axonal growth and myelination in the developing hippocampus. Given that microglia are involved in these developmental processes, we tested whether BDS impairs microglial activity in the hippocampus of 14 (during BDS) and 28-day old mice (one week after BDS). We found that BDS increased the density and altered the morphology of microglia in the hippocampus of 14-day old pups, effects that were no longer present on postnatal day (PND) 28. Despite the normal cell number and morphology seen at PND28, the molecular signature of hippocampal microglia, assessed using the NanoString immune panel, was altered at both ages. We showed that during normal hippocampal development, microglia undergo significant changes between PND14 and PND28, including reduced cell density, decreased ex vivo phagocytic activity, and an increase in the expression of genes involved in inflammation and cell migration. However, microglia harvested from the hippocampus of 28-day old BDS mice showed an increase in phagocytic activity and reduced expression of genes that normally increase across development. Promoter analysis indicated that alteration in the transcriptional activity of PU.1, Creb1, Sp1, and RelA accounted for most of the transcriptional changes seen during normal microglia development and for most of the BDS-induced changes at PND14 and PND28. These findings are the first to demonstrate that early life stress dysregulates microglial function in the developing hippocampus and to identify key transcription factors that are likely to mediate these changes.

Serum copeptin in children exposed to maltreatment

AIM

Childhood maltreatment (CM) has been related to a persistent reprograming of stress-response. Copeptin is a marker of hypothalamic-pituitary-adrenal axis activation; however, few studies have examined copeptin levels in children exposed to CM. The aim of this study was to compare serum copeptin levels in children reporting child abuse and/or neglect and children with no history of CM.

METHODS

This study included 65 children with a positive history of moderate to severe CM, as reported by themselves and their parent(s) during a clinical interview, and 71 children with no history of CM as a comparison group. CM was considered moderate to severe based on the child-reported frequency of being exposed to events related to sexual abuse, physical abuse, emotional abuse, emotional neglect, and/or physical neglect. Child psychopathology symptoms were assessed using the Child Behavior Checklist (CBCL). We measured serum copeptin concentration using enzyme-linked immunosorbent assay.

RESULTS

Children exposed to CM exhibited higher levels of serum copeptin compared to children without CM when controlling for sex, age, and psychiatric morbidity. The CBCL total score, including internalizing and externalizing symptoms, was higher in children with CM. We found no correlation between copeptin and CBCL scores for internalizing symptoms and externalizing symptoms.

CONCLUSION

CM is associated with copeptin serum levels independently of age, sex, and symptom severity. Copeptin is a promising new biomarker for children with a history of abuse and/or neglect.

Distinct behavioral and immunoendocrine parameters during crack cocaine abstinence in women reporting childhood abuse and neglect

AIM

To assess plasma levels of cortisol and cytokines between cocaine-dependent women with and without childhood maltreatment (CM) history during cocaine detoxification treatment.

METHOD

We assessed immunoendocrine and clinical parameters of 108 crack cocaine female users during 3 weeks of inpatient detoxification treatment, and 24 healthy women to obtain reference values. Women with (CM+, n=53) or without (CM-, n=55) CM history were identified answering the Childhood Trauma Questionnaire (CTQ). Blood samples and clinical assessment were collected before lunch during the first, second and third week post-treatment admission. Flow cytometry was used to assess TNF-α, IFN-γ, IL-2, IL-4, IL-6, IL-10, IL-17A plasma levels and ELISA assay was used to measure plasma cortisol levels.

RESULTS

At baseline, lower Th1 and Th17-related cytokines levels and higher Th2 cytokines levels were observed in crack cocaine users compared with reference values. Cytokines levels of cocaine dependents gradually became closer to reference values along detoxification treatment. However, when CM+ and CM- groups were compared, increased levels of IL-6, IL-4 and TNF-α across time were observed in CM+ group only. Additionally, a Th1/Th2 immune imbalance was observed within CM+ group, which was negatively correlated with the severity of the crack withdrawal. Finally, loading trauma exposure severity, immunoendocrine and clinical parameters in factor analysis, we identified three clusters of observed variables during detoxification: (1) systemic immunity and trauma exposure, (2) pro-inflammatory immunity and (3) behavior

CONCLUSION

Our results suggest the existence of an immunological phenotype variant associated with CM exposure during crack cocaine detoxification of women.

Hidden Wounds? Inflammatory Links Between Childhood Trauma and Psychopathology

Childhood trauma is a key risk factor for psychopathology. However, little is known about how exposure to childhood trauma is translated into biological risk for psychopathology. Observational human studies and experimental animal models suggest that childhood exposure to stress can trigger an enduring systemic inflammatory response not unlike the bodily response to physical injury. In turn, these "hidden wounds" of childhood trauma can affect brain development, key behavioral domains (e.g., cognition, positive valence systems, negative valence systems), reactivity to subsequent stressors, and, ultimately, risk for psychopathology. Further research is needed to better characterize the inflammatory links between childhood trauma and psychopathology. Detecting and healing these hidden wounds may help prevent and treat psychopathology emerging after childhood trauma.

An overview of maternal separation effects on behavioural outcomes in mice: Evidence from a four-stage methodological systematic review

Early life stress (ELS) developmental effects have been widely studied by preclinical researchers. Despite the growing body of evidence from ELS models, such as the maternal separation paradigm, the reported results have marked inconsistencies. The maternal separation model has several methodological pitfalls that could influence the reliability of its results. Here, we critically review 94 mice studies that addressed the effects of maternal separation on behavioural outcomes. We also discuss methodological issues related to the heterogeneity of separation protocols and the quality of reporting methods. Our findings indicate a lack of consistency in maternal separation effects: major studies of behavioural and biological phenotypes failed to find significant deleterious effects. Furthermore, we identified several specific variations in separation methodological procedures. These methodological variations could contribute to the inconsistency of maternal separation effects by producing different degrees of stress exposure in maternal separation-reared pups. These methodological problems, together with insufficient reporting, might lead to inaccurate and unreliable effect estimates in maternal separation studies.

Childhood Maltreatment in the Migraine Patient

OPINION STATEMENT

Maltreatment during childhood increases vulnerability to a host of health disorders, including migraine. Putative mechanisms linking maltreatment and migraine include stress-induced dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, as well as disruption of other stress-mediating homeostatic systems, including those involving endocannabinoids, monoamine neurotransmitters, oxytocin, and inflammation. Prolonged elevation of glucocorticoids alters the neural architecture of the limbic system, resulting in the structural as well as functional changes described in both maltreatment and in migraine. Although treatment trials for migraine have not stratified participants by abuse history, strategies, such as cognitive behavioral therapy, which alter stress responsivity, may be particularly effective in this subgroup. Some therapies involving the endocannabinoid, serotonergic, oxytonergic, and inflammatory systems are under investigation for migraine. Anti-epileptic drugs such as valproate and topiramate, which are FDA approved for migraine treatment, are also known to interfere with epigenetic changes induced by stress. Discerning the role for this mechanism in treatment of maltreated migraineurs may introduce another therapeutic avenue.

Absolute Measurements of Macrophage Migration Inhibitory Factor and Interleukin-1-β mRNA Levels Accurately Predict Treatment Response in Depressed Patients

BACKGROUND

Increased levels of inflammation have been associated with a poorer response to antidepressants in several clinical samples, but these findings have had been limited by low reproducibility of biomarker assays across laboratories, difficulty in predicting response probability on an individual basis, and unclear molecular mechanisms.

METHODS

Here we measured absolute mRNA values (a reliable quantitation of number of molecules) of Macrophage Migration Inhibitory Factor and interleukin-1β in a previously published sample from a randomized controlled trial comparing escitalopram vs nortriptyline (GENDEP) as well as in an independent, naturalistic replication sample. We then used linear discriminant analysis to calculate mRNA values cutoffs that best discriminated between responders and nonresponders after 12 weeks of antidepressants. As Macrophage Migration Inhibitory Factor and interleukin-1β might be involved in different pathways, we constructed a protein-protein interaction network by the Search Tool for the Retrieval of Interacting Genes/Proteins.

RESULTS

We identified cutoff values for the absolute mRNA measures that accurately predicted response probability on an individual basis, with positive predictive values and specificity for nonresponders of 100% in both samples (negative predictive value=82% to 85%, sensitivity=52% to 61%). Using network analysis, we identified different clusters of targets for these 2 cytokines, with Macrophage Migration Inhibitory Factor interacting predominantly with pathways involved in neurogenesis, neuroplasticity, and cell proliferation, and interleukin-1β interacting predominantly with pathways involved in the inflammasome complex, oxidative stress, and neurodegeneration.

CONCLUSION

We believe that these data provide a clinically suitable approach to the personalization of antidepressant therapy: patients who have absolute mRNA values above the suggested cutoffs could be directed toward earlier access to more assertive antidepressant strategies, including the addition of other antidepressants or antiinflammatory drugs.

Is it time for immunopsychiatry in psychotic disorders?

INTRODUCTION

Immune dysregulation is suggested to play an important aetiological role in schizophrenia (SZ) and bipolar disorder (BD) potentially driving neurodevelopmental pathways. Immune dysfunction may precede the onset of psychiatric disorders and parallel the development of multiaxial comorbidity, including suicidal behaviour and metabolic and autoimmune disorders. Depicting the source of the chronic low-grade inflammatory component in SZ and BD is thus a research priority. Strong environmental insults early in life, such as infections, acting on a background of genetic vulnerability, may induce potent and enduring inflammatory responses setting a state of liability to second-hit environmental encounters, namely childhood trauma, drug abuse or additional infectious exposures. The immunogenetic background of susceptibility, suggested to be not only lying within the HLA locus but also implicating inherited deficits of the innate immune system, may amplify the harmful biological effects of infections/psychosocial stress leading to the manifestation of a broad range of psychiatric symptoms.

OBJECTIVES

The present review aims to discuss the following: (i) biological arguments in favour of a chronic low-grade inflammation in SZ and BD and its potential origin in the interaction between the immunogenetic background and environmental infectious insults, and (ii) the consequences of this inflammatory dysfunction by focusing on N-methyl-D-aspartate (NMDA) receptor antibodies and activation of the family of human endogenous retroviruses (HERVs).

CONCLUSIONS

Specific therapeutic approaches targeting immune pathways may lead the way to novel personalized medical interventions, improvement of quality of life and average life expectancy of psychiatric patients, if not even prevent mood episodes and psychotic symptoms.

Childhood trauma and adulthood inflammation: a meta-analysis of peripheral C-reactive protein, interleukin-6 and tumour necrosis factor-α

Childhood trauma confers higher risk of adulthood physical and mental illness; however, the biological mechanism mediating this association remains largely unknown. Recent research has suggested dysregulation of the immune system as a possible biological mediator. The present paper conducted a meta-analysis to establish whether early-life adversity contributes to potentially pathogenic pro-inflammatory phenotypes in adult individuals. A systematic search of Pubmed, PsycINFO, EMBASE, Scopus and Medline identified 25 articles for the meta-analysis, including 18 studies encompassing a sample of 16 870 individuals for C-reactive protein (CRP), 15 studies including 3751 individuals for interleukin-6 (IL-6) and 10 studies including 881 individuals for tumour necrosis factor-α (TNF-α). Random-effects meta-analysis showed that individuals exposed to childhood trauma had significantly elevated baseline peripheral levels of CRP (Fisher's z=0.10, 95% confidence interval (CI)=0.05-0.14), IL-6 (z=0.08, 95% CI=0.03-0.14) and TNF-α (z=0.23, 95% CI=0.14-0.32). Subgroup analyses for specific types of trauma (sexual, physical or emotional abuse) revealed that these impact differentially the single inflammatory markers. Moreover, meta-regression revealed greater effect sizes in clinical samples for the association between childhood trauma and CRP but not for IL-6 or TNF-α. Age, body mass index (BMI) and gender had no moderating effects. The analysis demonstrates that childhood trauma contributes to a pro-inflammatory state in adulthood, with specific inflammatory profiles depending on the specific type of trauma.

Child maltreatment, inflammation, and internalizing symptoms: Investigating the roles of C-reactive protein, gene variation, and neuroendocrine regulation

Prior research has found inconsistent evidence regarding the association among childhood adversity, inflammation, and internalizing symptoms, perhaps because previous studies have yet to adequately integrate important factors such as the timing of the adversity, genetic variation, and other relevant processes such as neuroendocrine regulation. The aims of the present study were threefold: (a) to determine whether the effect of the timing of child maltreatment on C-reactive protein (CRP), an inflammatory marker, varies by CRP gene variation; (b) to explore whether links between salivary CRP and childhood internalizing symptoms depend on the presence and timing of maltreatment experiences; and (c) to investigate the role of CRP in the relations between child neuroendocrine regulation and internalizing symptoms and examine whether these associations are moderated by the presence and timing of child maltreatment. Participants included a sample of 267 maltreated and 222 nonmaltreated children (M age = 9.72, SD = 0.99; 52.4% male; 66% African American) who attended a summer day camp research program designed for school-aged low-income children. Department of Human Services records were examined to determine the onset and recency of maltreatment for children in the maltreated group. The results indicated that among children with recent onset maltreatment, those with at least one A allele from CRP single nucleotide polymorphism rs1417938 evidenced significantly higher CRP levels compared to recently maltreated children carrying the TT genotype. Moreover, higher levels of CRP were associated with higher levels of internalizing symptoms only for recently maltreated children. Finally, we did not find support for salivary CRP as a mechanism in the relation between neuroendocrine regulation and childhood internalizing symptoms. Our findings highlight the importance of the timing of child maltreatment and have important implications for characterizing variability in inflammation and internalizing symptoms among youth.

Adversity in preschool-aged children: Effects on salivary interleukin-1β

Exposure to early life adversity is linked to impaired affective, cognitive, and behavioral functioning and increases risk for various psychiatric and medical conditions. Stress-induced increases in pro-inflammatory cytokines may be a biological mechanism of these effects. Few studies have examined cytokine levels in children experiencing early life adversity, and very little research has investigated cytokines or other markers of inflammation in saliva. In the present study, we examined salivary interleukin (IL)-1β and C-reactive protein (CRP) levels in relation to stress exposure in 40 children aged 3 to 5 years who were enrolled in a larger study of early life adversity. Childhood maltreatment status was assessed via review of child welfare records. Contextual stress exposure, traumatic life event history, and symptoms of psychopathology were assessed via caregiver interviews at a home visit. In a subsequent visit, salivary IL-1β and CRP were obtained before and after participation in four emotion-eliciting tasks. The number of past-month contextual stressors, lifetime contextual stressors, and traumatic life events each demonstrated a significant main effect on IL-1β. Baseline IL-1β was positively associated with each of the significant main-effect adversities. Postchallenge IL-1β displayed positive associations with each adversity variable, but these were not significant. CRP was not significantly associated with any of the adversity variables. Given the evidence suggesting the involvement of IL-1β in the neuropathology of psychiatric conditions, these results may have important implications for developmental outcomes.

Child maltreatment and pediatric asthma: a review of the literature

BACKGROUND

Child maltreatment is a common problem with known adverse consequences, yet its contributions to the development and course of pediatric asthma are only poorly understood.

MAIN

This review first describes possible pathways connecting child maltreatment to pediatric asthma, including aspects of the physical home environment, health behaviors and disease management, and psychological consequences of child maltreatment. We subsequently review existing studies, which generally report an association between maltreatment experiences and asthma outcomes in childhood. However, this literature is in its early stages; there are only a handful studies, most of them rely on self-reports of both child maltreatment and asthma history, and none have investigated the physiological underpinnings of this association. Taken together, however, the studies are suggestive of child maltreatment playing a role in pediatric asthma incidence and expression that should be explored further.

CONCLUSION

Existing data are sparse and do not allow for specific conclusions. However, the data are suggestive of child maltreatment influencing asthma risk and morbidity long before the adult years. Future research should focus on understanding how child maltreatment contributes to asthma disease risk and progression in this highly vulnerable population.

Childhood maltreatment and pre-pregnancy obesity: a comparison of obese, overweight, and normal weight pregnant women

Pre-pregnancy overweight and obesity is associated with poor health outcomes for the mother and the child. General population studies suggest that childhood maltreatment is associated with obesity in adulthood. The aim of our study was to examine the association between pre-pregnancy overweight and obesity and a history of childhood abuse or neglect including different stages of severity of abuse and neglect. Three hundred twenty-six normal weight, overweight, or obese pregnant women reported demographic data, height and weight, and general psychological distress at 18-22 weeks of gestation. Childhood maltreatment was assessed using the Childhood Trauma Questionnaire. Associations were examined using logistic regression analyses and a reference group of normal weight women. Fifty percent reported a history of abuse or neglect. After adjusting for age, education, income, marital status, and the number of previous children, pre-pregnancy overweight and obesity were strongly associated with severe physical abuse (overweight: OR = 8.33, 95% CI 1.48-47.03; obesity: OR = 6.31, 95% CI 1.06-37.60). Women with severe physical neglect (OR = 4.25, 95% CI 1.23-14.74) were at increased risk of pregnancy overweight. We found a dose-response relationship between physical abuse and pre-pregnancy overweight and obesity. Whereas other studies report an association between childhood maltreatment and pre-pregnancy obesity, this is the first study that found an association between childhood maltreatment and pre-pregnancy overweight. Considering the severe health risks of pre-pregnancy overweight and obesity and the long-term consequences of childhood maltreatment, affected women constitute a subgroup with special needs in prenatal care. Further research is needed to improve the understanding of the underlying mechanisms.

Adult Sexual Experiences as a Mediator Between Child Abuse and Current Secretory Immunoglobulin A Levels

The current study investigated whether a history of child abuse is a predictor of adult immune status, with unwanted adult sexual experiences as a proximal mediator. Participants included 89 young adult women (M(age) = 19.24) who were classified as having experienced no child abuse, child physical abuse, or child sexual abuse, based upon self-reported victimization history before 14 years of age. Participants also reported on unwanted sexual experiences in young adulthood and provided four saliva samples, which were collected over two consecutive days to determine secretory immunoglobulin A (sIgA). Age and negative life events were considered as covariates. The results indicated that adult sexual victimization partially mediated the relationship between child abuse (physical and sexual) and sIgA. Specifically, child abuse experiences predicted more adult sexual victimization experiences, which in turn predicted lower sIgA levels. These findings support long-term health effects of victimization, and suggest that the influence of child abuse on sIgA may be perpetuated through adult victimization. Prevention efforts should aim to empower child maltreatment survivors with skills to prevent adult re-victimization. By thwarting future unwanted sexual experiences in adulthood, individuals will be better protected from the health impairments associated with early abuse experiences.