Clustering of depression and inflammation in adolescents previously exposed to childhood adversity

The role of childhood maltreatment in cortisol in the hypothalamic-pituitary-adrenal (HPA) axis in methamphetamine-dependent individuals with and without depression comorbidity and suicide attempts

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) axis dysregulation which was found to have an important role in the pathophysiology of depression, suicide, and substance dependence, may be influenced by childhood maltreatment (CM). The present study aimed to investigate the relationship between CM and cortisol changes in methamphetamine-dependent individuals.

METHODS

In a cross-sectional study, methamphetamine-dependent individuals (n = =195) with or without both comorbid major depressive disorder (MDD) and a history of suicide attempts were selected and completed the Childhood Trauma Questionnaire-Short Form (CTQ-SF), the Beck Scale for Suicide Ideation (BSSI), and the Beck Depression Inventory-II (BDI-II). To assess cortisol levels, saliva samples were collected at six time intervals for two consecutive days.

RESULTS

A history of CM significantly predicted wake-up cortisol level, cortisol awakening response (CAR), and diurnal cortisol slope. Methamphetamine-dependent individuals with both MDD and lifetime suicide attempts had higher CM and higher cortisol levels with a blunted diurnal cortisol slope than individuals who were merely methamphetamine-dependent. Individuals with high CM showed higher cortisol levels with a blunted diurnal slope than those with low or without CM.

LIMITATIONS

Cross-sectional data and use of self-report scales, especially retrospective measurements (e.g., the CTQ-SF), were important limitations of this study.

CONCLUSION

Findings suggest that methamphetamine-dependent individuals with adverse psychological factors such as CM, MDD, and suicide attempts may show dysregulation in biological factors including cortisol level. In addition, CM and its effects on cortisol in the HPA axis may emerge as important factors regarding psychopathological use of methamphetamine.

The Psychobiology of Bereavement and Health: A Conceptual Review From the Perspective of Social Signal Transduction Theory of Depression

Losing a spouse is considered one of the most stressful life events a person can experience. Particularly in the immediate weeks and months after the loss, bereavement is associated with a significantly increased risk of morbidity and mortality. Despite an abundance of research aimed at identifying risk factors for adverse health outcomes following marital death, the mechanisms through which mental and physical health problems emerge following bereavement remain poorly understood. To address this issue, the present review examines several pathways that may link bereavement and health, including inflammation and immune dysregulation, genetic and epigenetic changes, gut microbiota activity, and biological aging. We then describe how these processes may be viewed from the perspective of the Social Signal Transduction Theory of Depression to provide a novel framework for understanding individual differences in long-term trajectories of adjustment to interpersonal loss. Finally, we discuss several avenues for future research on psychobiological mechanisms linking bereavement with mental and physical health outcomes.

Depressive and Anxiety Symptoms among Pediatric In-Patients with Dengue Fever: A Case-Control Study

BACKGROUND

Psychiatric symptoms have been reported in adult patients with dengue fever (DF); however, information on pediatric patients remains inadequate. We sought to identify the prevalence and predictors of depressive and anxiety symptoms and identify other psychiatric symptoms among pediatric patients with DF. This case-control study involved pediatric in-patients (n = 225) who had clinical or serologic-confirmed DF and healthy school-based controls (n = 260). Participants completed the Revised Child Anxiety and Depression Scale (RCADS).

RESULTS

The prevalence of depressive (13.3%) and anxiety (34.2%) symptoms among pediatric patients with DF was significantly (p < 0.001) higher than that among controls (3.5% and 16.2%, respectively). Multiple linear regression analysis found that age, family history of DF, ≤2 days of hospitalization, myalgia, and arthralgia were predictors of increased depressive and anxiety symptoms among the patients. Further, 26.7% of pediatric patients reported irritability, agitation, visual hallucinations, and aggressiveness.

CONCLUSION

Pediatric patients present depressive and anxiety symptoms whose levels were associated with social and clinical factors. However, whether these symptoms are present only during the infection or may still persist after recovery or are brought by children's adverse reactions to hospitalization are unknown, and thus, further studies are needed.

The relationship between minority stress and biological outcomes: A systematic review

Sexual minority (non-heterosexual) individuals experience higher rates of physical health problems. Minority stress has been the primary explanatory model to account for this disparity. The purpose of this study was to identify in published research empirically established relationships between minority stress processes and biological outcomes and identify avenues for future research. The PubMed database was queried with search terms relevant to minority stress and a comprehensive list of physical and biological outcomes. To be included in the analysis, studies had to examine the relationship between minority stress and a biological outcome among sexual minority individuals. Those meeting inclusion criteria were coded for key variables including methodology used, positive and null results, participant characteristics, and specific minority stress processes and biological outcomes considered. In total, 26 studies met inclusion criteria. Studies tested relationships between specific minority stress processes including prejudice, expectations of prejudice, concealment of sexual orientation, and internalized stigma and multiple biological outcomes, such as overall physical health, immune response, HIV specific outcomes, cardiovascular outcomes, metabolic outcomes, cancer related outcomes, and hormonal outcomes. Studies included both analyses that detected this relationship (42% of analyses) and analyses that did not detect this relationship (58%). There is substantial evidence to support the relationship between minority stress and biological outcomes, yet additional research is needed to identify the measurements and outcomes that have the most rigorous and replicable results.

Externalizing trajectories predict elevated inflammation among adolescents exposed to early institutional rearing: A randomized clinical trial

BACKGROUND

There has been mounting interest in the pathophysiological relation between inflammation and psychopathology. In this paper, we examined associations between internalizing and externalizing psychopathology and inflammation in adolescents with a history of severe psychosocial deprivation and children reared in typical family contexts.

METHOD

The Bucharest Early Intervention Project is a longitudinal randomized trial of high-quality foster care as an alternative to institutional care. This report is based on 56 institutionalized children randomized to care as usual, 59 institutionalized children randomized to foster care, and 101 never institutionalized children who were recruited as an in-country comparison sample. Externalizing and internalizing behaviors were reported by parents and teachers at ages 8, 12, and 16. At age 16, C-reactive protein (CRP) was derived from blood spots in a subset of participants (n = 127). Multiple-group latent growth curve models were used to examine externalizing and internalizing trajectories and their associations with CRP.

RESULTS

Among children assigned to care as usual, higher levels of externalizing behaviors at age 8, as well as smaller decreases in these behaviors from 8 to 16 years predicted higher levels of CRP at age 16. In the same group of children, higher internalizing behaviors at age 8, but not the rate of change in these behaviors, also predicted higher levels of CRP. In contrast, these relations were not observed in the children assigned to foster care and never institutionalized controls.

CONCLUSIONS

Early institutional rearing is associated with a coupling of psychopathology and inflammation, whereas early placement into foster care buffers against these risks. These findings have implications for promoting healthy mental and physical development amongst institutionalized children.

Stress, sex hormones, inflammation, and major depressive disorder: Extending Social Signal Transduction Theory of Depression to account for sex differences in mood disorders

Social Signal Transduction Theory of Depression is a biologically plausible, multi-level theory that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental adversity with internal biological processes that drive depression pathogenesis, maintenance, and recurrence. Central to this theory is the hypothesis that interpersonal stressors involving social threat (e.g., social conflict, evaluation, rejection, isolation, and exclusion) upregulate inflammatory processes that can induce several depressive symptoms, including sad mood, anhedonia, fatigue, psychomotor retardation, and social-behavioral withdrawal. The original article describing this formulation (Psychol Bull 140:774-815, 2014) addressed critical questions involving depression onset and recurrence, as well as why depression is strongly predicted by early life stress and comorbid with anxiety disorders and certain physical disease conditions, such as asthma, rheumatoid arthritis, chronic pain, and cardiovascular disease. Here, we extend the theory to help explain sex differences in depression prevalence, which is a defining feature of this disorder. Central to this extension is research demonstrating that ovarian hormone fluctuations modulate women's susceptibility to stress, brain structure and function, and inflammatory activity and reactivity. These effects are evident at multiple levels and are highly context-dependent, varying as a function of several factors including sex, age, reproductive state, endogenous versus exogenous hormones, and hormone administration mode and dose. Together, these effects help explain why women are at greater risk for developing inflammation-related depressed mood and other neuropsychiatric, neurodevelopmental, and neurodegenerative disorders during the reproductive years, especially for those already at heightened risk for depression or in the midst of a hormonal transition period.

Cultivating a healthy neuro‐immune network: A health psychology approach

The field of psychoneuroimmunology (PNI) examines interactions among psychological and behavioral states, the brain, and the immune system. Research in PNI has elegantly documented effects of stress at multiple levels of the neuro-immune network, with profound implications for both physical and mental health. In this review, we consider how the neuro-immune network might be influenced by "positive" psychological and behavioral states, focusing on positive affect, eudaimonic well-being, physical activity, and sleep. There is compelling evidence that these positive states and behaviors are associated with changes in immune activity in the body, including reductions in peripheral inflammatory processes relevant for physical health. Growing evidence from animal models also suggests effects of positive states on immune cells in the brain and the blood-brain barrier, which then impact critical aspects of mood, cognition, and behavior. Tremendous advances are being made in our understanding of neuro-immune dynamics; one of the central goals of this review is to highlight recent preclinical research in this area and consider how we can leverage these findings to investigate and cultivate a healthy neuro-immune network in humans.

Fine Particle Air Pollution and Physiological Reactivity to Social Stress in Adolescence: The Moderating Role of Anxiety and Depression

OBJECTIVE

Exposure to high levels of fine particle air pollution (PM2.5) is associated with adolescent pathophysiology. It is unclear, however, if PM2.5 is associated with physiology within psychosocial contexts, such as social stress, and whether some adolescents are particularly vulnerable to PM2.5-related adverse effects. This study examined the association between PM2.5 and autonomic reactivity to social stress in adolescents and tested whether symptoms of anxiety and depression moderated this association.

METHODS

Adolescents from Northern California (N = 144) participated in a modified Trier Social Stress Test while providing high-frequency heart rate variability and skin conductance level data. PM2.5 data were recorded from CalEnviroScreen. Adolescents reported on their own symptoms of anxiety and depression using the Youth Self-Report, which has been used in prior studies and has good psychometric properties (Cronbach's α in this sample was .86).

RESULTS

Adolescents residing in neighborhoods characterized by higher concentrations of PM2.5 demonstrated greater autonomic reactivity (i.e., indexed by lower heart rate variability and higher skin conductance level) (β = .27; b = .44, p = .001, 95% CI = 0.19 to 0.68) in response to social stress; this association was not accounted for by socioeconomic factors. In addition, adolescents who reported more severe anxiety and depression symptoms showed the strongest association between PM2.5 and autonomic reactivity to social stress (β = .53; b = .86, p < .001, 95% CI = 0.48 to 1.23).

CONCLUSIONS

Exposure to PM2.5 may heighten adolescent physiological reactivity to social stressors. Moreover, adolescents who experience anxiety and depression may be particularly vulnerable to the adverse effects of PM2.5 on stress reactivity.

Reactive Depression: Lost in Translation!

The old classification of depression as reactive and endogenous, which are still observed in clinical practice, both cannot be accommodated under the current rubric of major depression. This is because psychiatric nosology under the Diagnostic and Statistical Manual of Mental Disorders (DSM) and its latest fifth edition (DSM-V) is still descriptive and not etiologic. The aim of this review was to revisit reactive and endogenous categories of depression from the perspective of today's understanding of etiological pathways. From an epigenetic perspective, the old dichotomy of reactive versus endogenous is interrelated through the impact of the environment (e.g., stress). This includes familial or prenatal depression, where the environmental impact is before birth, or childhood depression, where the early life stress is the precipitating factor to genetic susceptibility. In conclusion, searching for both environmental impact (e.g., stressors) and genetic predispositions in depression, even at a clinical level, could help clinicians with better therapeutic decisions.

Depressive symptoms and immune transcriptional profiles in late adolescents

BACKGROUND

Rates of depression increase and peak during late adolescence and alterations in immune processes are thought to be both a risk factor and outcome of depression. However, few studies have examined depression-immune dynamics among adolescents. Using a functional genomics approach, the current study examined whether depressive symptoms were associated with activation of a gene expression profile, characterized by upregulated expression of pro-inflammatory-related genes and downregulated expression of antiviral-related genes in a sample of older adolescents (M_age = 18.37, SD = 0.51).

METHOD

Participants (n = 87) reported on their depressive symptoms during the past week using the CES-D, and provided blood samples for genome-wide transcriptional profiling of mRNA.

RESULTS

Adolescents with clinically-significant levels of depressive symptoms (CES-D ≥ 16) exhibited upregulated expression of inflammation-related genes and downregulated expression of antiviral-related genes compared to their peers with lower levels of depressive symptoms (CES-D < 16). Bioinformatics analyses suggested that this pattern of differential gene expression was mediated by greater activity of the pro-inflammatory transcription factor, nuclear factor-kappa B (NF-κB), and reduced activity of glucocorticoid receptors (GRs) and interferon response factors (IRFs). Additional analyses implicated monocytes, B cells, and dendritic cells as primary cellular sources of the observed gene expression patterns associated with depressive symptoms.

CONCLUSION

Results are consistent with past work demonstrating links between depression and altered immunity. They provide a molecular basis for these associations and suggest that the underlying molecular signature may emerge as early as late adolescence when rates of depression tend to increase.

Interleukin 6 as a pathogenic factor mediating clinical manifestations and a therapeutic target for rheumatic diseases and depressive disorders

The review summarizes current idea on the key role of interleukin 6 (IL-6) in the pathogenesis of rheumatic diseases (RDs) and depressive disorders. It considers in detail the mechanisms by which IL6 induces the clinical and laboratory manifestations of RDs and depression; the influence of precipitating and predisposing stress factors, including childhood mental traumas, which increase the risk of RDs and depression, on IL-6 production. Particular attention is paid to the consideration of prospects for using IL-6 inhibitors in the therapy of depression.

Interplay between pro-inflammatory cytokines, childhood trauma, and executive function in depressed adolescents

BACKGROUND

Pro-inflammatory cytokines have been linked to depression, early childhood trauma, and impairment in executive function in adults. Whether these links are present during adolescence, a time when vulnerability to depression is heightened, a point more proximal to childhood trauma, and a critical period of brain development, is not well understood.

METHOD

Serum levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor alpha (TNF-α) were measured in 70 adolescents aged 12-17, including 40 with a DSM-IV depressive disorder (DEP), a sub-set (n = 22) of whom reported a history of childhood trauma (DEP-T), and 30 healthy controls (HCs). Participants completed performance-based (Parametric Go/No-Go Task) and observer-rated (Behavior Rating Inventory of Executive Function) measures of executive function. Procedures were conducted at a subspecialty clinic (Dec 2015-June 2017).

RESULTS

IL-6 was elevated in DEP and DEP-T adolescents compared to controls (p = .014) and TNF-α was elevated in DEP participants only (p = .040) compared to controls, whereas no group differences were found in IL-1β (p = .829). Additionally, DEP-T participants demonstrated relative deficits in performance-based (p = .044) and observer-rated inhibitory control (p = .049) compared to controls. Across the whole sample, TNF-α was associated with performance-based (r = -0.25, p = .039) and observer-rated (r = 0.32, p = .009) inhibitory control deficits. In subgroup analyses, TNF-α was associated with increased observer-rated inhibitory deficits in DEP, and at the trend level, with reduced inhibitory control performance in DEP-T.

CONCLUSIONS

The current results suggest that inflammation may be a marker of disease processes in adolescent depression. Though longitudinal studies are needed, depressed adolescents with childhood trauma exposure appear to constitute a uniquely vulnerable group in terms of objective risk for executive dysfunction. Immune dysregulation may partly contribute to this risk.

Inflammatory Proteins Predict Change in Depressive Symptoms in Male and Female Adolescents

Inflammation has been implicated in depressive symptoms, but few studies use longitudinal designs with adolescents. Furthermore, the extant literature has yielded inconsistent results. Blood was collected from a community sample of 201 adolescents (109 female, ages 12.3-20.0) and analyzed for inflammatory proteins. Up to five follow-up assessments of depressive symptoms were conducted. Multi-level modeling indicated that high C-reactive protein (CRP) (but no other proinflammatory markers) predicted depressive symptom increases. Three-way interactions between different inflammatory biomarkers, sex, and months-to-follow-up predicted change in depressive symptoms. Higher interleukin-6 predicted increased depressive symptoms at 13-31 months after baseline assessment of depression and inflammation for females. Higher tumor necrosis factor-alpha predicted increased depressive symptoms at < 1 month after baseline for males and 13-31 months after baseline for females. Higher interleukin-8 in males predicted lower depressive symptoms at 31 months after baseline. Exploratory post-hoc analyses examined these predictive associations for specific subsets of depressive symptoms. These findings are the first to support the predictive association of elevated CRP for depressive symptoms in a community adolescent sample and serve as preliminary evidence that the relationship between cytokines and later depressive symptoms differs by sex, time-to-follow-up, and the specific biomarker.

[Inflammatory Biomarkers and Postpartum Depression: A Systematic Review of Literature]

OBJECTIVE

Postpartum Depression (PPD) affects over 15% new mothers. Its etiology is multifactorial and still partly unknown. Some hypotheses suggest a link with inflammation. This review aims to explore the existence of inflammatory biomarkers associated with PPD. The possibility of potential adjunct treatments, linked with these biomarkers, will be discussed.

METHOD

The systematic review of literature was performed using in PubMed, PsycInfo and Embase, and 25 articles were included. Various biomarkers were identified. The most often studied are C-reactive protein (CRP), interleukins 6 and 10, tumor necrosis factor-alpha and interferon-gamma.

RESULTS

Although few results appear as significant during the various testing times, the dosage of some inflammation biomarkers, including CRP, at the very end of pregnancy or immediately after delivery could predict PPD. Interactions between inflammation and the corticotropic axis could explain PPD onset. Epigenetic mechanisms could lead to pro-inflammatory state. Several therapeutics provide interest due to their anti-inflammatory property.

CONCLUSIONS

Further studies are needed to assess these biomarkers value as predictive factors of PPD and to consider adjunct treatments to antidepressants. If this value is confirmed, the inflammatory marker dosage, in particular CRP, could help to provide early screening of women at risk of PPD, parallel of the clinical evaluation. A zinc supplementation could then be offered.

Microglia along sex lines: From brain colonization, maturation and function, to implication in neurodevelopmental disorders

In addition to their traditional role as immune sentinels, recent discoveries over the last decade have shown that microglial functions now include regulation of neuronal/glial cell migration, differentiation and maturation, as well as neuronal network formation. It was thus proposed that disruption of these microglial roles, during critical periods of brain development, could lead to the pathological onset of several neurodevelopmental disorders, including autism spectrum disorder, attention deficit hyperactivity disorder, epilepsy, schizophrenia, and major depressive disorder. The prevalence of these disorders exhibits a clear distinction along sex lines with very little known about the mechanisms underlying this difference. One of the fundamental discoveries that arose from recent research into the physiological roles of microglia in neurodevelopment is their sexual dimorphism, raising the intriguing possibility that sex differences in microglial colonization, maturation and/or function in the developing brain could underlie the emergence of various neurodevelopmental disorders. This review discusses the physiological roles of microglia across neurodevelopment, these roles in the two sexes, and the recent evidence that microglial sexually dimorphic nature may contribute, at least partially, to neurodevelopmental disorders.

The Consequences of Foster Care Versus Institutional Care in Early Childhood on Adolescent Cardiometabolic and Immune Markers: Results From a Randomized Controlled Trial

OBJECTIVE

Children exposed to institutional rearing often exhibit problems across a broad array of developmental domains. We compared the consequences of long-term, high-quality foster care versus standard institution-based care, which began in early childhood on cardiometabolic and immune markers assessed at the time of adolescence.

METHODS

The Bucharest Early Intervention Project is a longitudinal investigation of children institutionalized during early childhood (ages 6 to 30 months at baseline) who were subsequently randomized to either high-quality foster care or continued institutional care. At the age of 16 years, 127 respondents participated in a biomarker collection protocol, including 44 institutionalized children randomly assigned to receive care as usual, 41 institutionalized children randomized to be removed from institutional care and placed in high-quality foster care in infancy, and a control group of 42 demographically matched children raised in biological families. Outcomes included body mass index (BMI), systolic and diastolic blood pressure, C-reactive protein, interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor α, glycosylated hemoglobin A1c, and Epstein-Barr virus antibody titers.

RESULTS

Early institutional rearing was not associated with differences in cardiometabolic or immune markers. Randomization to foster care and age of placement into foster care were also unrelated to these markers, with the exception of BMI z-score, where children assigned to care as usual had lower BMI z-scores relative to children assigned to foster care (-0.23 versus 0.08, p = .06), and older age at placement was associated with lower BMI (β = -0.07, p = .03).

CONCLUSIONS

The impact of institutional rearing on measures of cardiometabolic health and immune system functioning is either absent or not evident until later in development. These findings provide new insights into the biological embedding of adversity and how it varies developmentally and across regulatory systems and adversity type.

CLINICAL TRIAL REGISTRATION

NCT00747396.

The psychological scars of suicide: Accounting for how risk for suicidal behavior is heightened by its past occurrence

Not only is suicidal behavior strongly predicted by its past occurrence, but the risk for recurrence appears to increase with each subsequent attempt. The current paper discusses a potential explanation for this phenomenon, that suicide attempts may leave a residual psychological scar that heightens risk for future attempts. This possibility is evaluated against two alternatives: (i) risk for first and subsequent suicide attempts is accounted for by a shared diathesis pre-existing the first lifetime attempt, and (ii) different rates of developmental decline in risk factors account for differences in prospective number of attempts. In this discussion, a formalized conceptual framework of psychological scarring is presented, along with considerations of particular relevance to its study. Finally, the clinical implications of determining the processes underlying the association between suicide attempts and heightened risk for recurrence are discussed.

Understanding the Relation Between Early-Life Adversity and Depression Symptoms: The Moderating Role of Sex and an Interleukin-1β Gene Variant

Pro-inflammatory cytokines, such as interleukin (IL)-6 and tumor necrosis factor-α (TNF-α), are thought to play a fundamental role in the pathogenesis of depression within a subset of individuals. However, the involvement of IL-1β has not been as consistently linked to depression, possibly owing to difficulties in detecting this cytokine in blood samples or that changes in circulating levels might only be apparent in a subgroup of patients who have experienced early-life adversity. From this perspective, the association between early-life adversity and depressive illness might depend on genetic variants regulating IL-1β activity. Considering the inflammatory-depression link, and that women are twice as likely to experience depression compared to men, the current study (N = 475 university students) examined the moderating role of three independent cytokine single nucleotide polymorphisms (SNPs; IL-1β rs16944, IL-6 rs1800795 SNP, TNF-α rs1800629) in the relationship between early-life adversity and depressive symptoms, and whether these relations differed between males and females. The relation between childhood adversity and depressive symptoms was moderated by the IL-1β SNP, and further varied according to sex. Specifically, among females, higher childhood maltreatment was accompanied by elevated depressive symptoms irrespective of the IL-1β SNP, but among males, this relationship was particularly pronounced for those carrying the GG genotype of the IL-1β SNP. These findings suggest that, in the context of early life adversity, genetic variations of IL-1β functioning are related to depressive symptomatology and this may vary among males and females. The present study also, more broadly, highlights the importance of considering the confluence of experiential factors (e.g., early life adversity) and personal characteristics (e.g., sex and genetics) in understanding depressive disorders, an approach increasingly recognized in developing personalized treatment approaches to this illness.

DNA methylation and inflammation marker profiles associated with a history of depression

Depression is a common and disabling disorder, representing a major social and economic health issue. Moreover, depression is associated with the progression of diseases with an inflammatory etiology including many inflammatory-related disorders. At the molecular level, the mechanisms by which depression might promote the onset of these diseases and associated immune-dysfunction are not well understood. In this study we assessed genome-wide patterns of DNA methylation in whole blood-derived DNA obtained from individuals with a self-reported history of depression (n = 100) and individuals without a history of depression (n = 100) using the Illumina 450K microarray. Our analysis identified six significant (Šidák corrected P < 0.05) depression-associated differentially methylated regions (DMRs); the top-ranked DMR was located in exon 1 of the LTB4R2 gene (Šidák corrected P = 1.27 × 10-14). Polygenic risk scores (PRS) for depression were generated and known biological markers of inflammation, telomere length (TL) and IL-6, were measured in DNA and serum samples, respectively. Next, we employed a systems-level approach to identify networks of co-methylated loci associated with a history of depression, in addition to depression PRS, TL and IL-6 levels. Our analysis identified one depression-associated co-methylation module (P = 0.04). Interestingly, the depression-associated module was highly enriched for pathways related to immune function and was also associated with TL and IL-6 cytokine levels. In summary, our genome-wide DNA methylation analysis of individuals with and without a self-reported history of depression identified several candidate DMRs of potential relevance to the pathogenesis of depression and its associated immune-dysfunction phenotype.

Early maternal sensitivity, attachment security in young adulthood, and cardiometabolic risk at midlife

Children who experience high-quality early parenting tend to have better physical health, but limited research has tested whether this association extends into adulthood using prospective, observational assessments. Likewise, mechanisms that may explain such links have not yet been illuminated. In this study, we test whether the quality of early maternal sensitivity experienced during the first 3½ years of life predicts cardiometabolic risk at midlife (ages 37 and 39 years) via attachment representations measured in young adulthood (ages 19 and 26 years). We do so by comparing the predictive significance of two different forms of attachment representations coded from the Adult Attachment Interview (AAI): (a) secure base script knowledge and (b) coherence of mind. Using data from the Minnesota Longitudinal Study of Risk and Adaptation, we find that early maternal sensitivity is negatively associated with cardiometabolic risk at midlife. Secure base script knowledge (but not coherence of mind) partially mediated this link. These findings are consistent with the possibility that early parenting has lasting significance for physical health in part by promoting higher levels of secure base script knowledge.

Early Attachment Disruption, Inflammation, and Vulnerability for Depression in Rodent and Primate Models

Early experiments in nonhuman primates established the relation between disruption of filial attachment and depressive-like outcomes. Subsequent studies in rats and mice have been instrumental in linking depressive-like outcomes to disturbances in maternal behavior. Another aspect of attachment disruption, absence of the attachment object per se, may be studied more effectively in a different laboratory rodent-the guinea pig. Here, we discuss the rationale for using guinea pigs for this work. We then review guinea pig studies providing evidence for inflammatory mechanisms mediating both depressive-like behavior during separation as well as sensitization of stress responsiveness such as is thought to lead to increased vulnerability to depression at later ages. Finally, we discuss recent complementary work in adult monkeys that suggests cross-species generalizability of broad principles derived from the guinea pig experiments. Overall, the findings provide experimental support for human research implicating inflammatory mechanisms in the development of increased stress responsiveness and vulnerability to depression following attachment disruption and other forms of early-life stress. Specifically, the findings suggest inflammatory mechanisms may set in motion a cascade of underlying processes that mediate later increased stress responsiveness and, therefore, depression susceptibility.

Salivary C-reactive protein among at-risk adolescents: A methods investigation of out of range immunoassay data

Inflammatory markers including C-Reactive Protein (CRP) are increasingly used within research and clinical settings. Yet, varying methodologies for cleaning immunoassay data with out of range (OOR) samples may alter characteristic levels of CRP, thereby obscuring interpretation and reliability. This study investigated the influence of eight immunoassay OOR data treatment techniques on salivary CRP (sCRP) samples from at-risk adolescents. Participants from the 'Sleep and Education: learning New Skills Early' (SENSE) Study were 86 adolescents at-risk for depression (50 female), aged 14.29 years (SD = 1.04). ANOVA results showed no statistically significant differences in average morning (F(7, 590) = 1.24, p = .28) and evening (F(7, 599)=1.29, p = .25) values produced by each OOR data cleaning technique. However, varying techniques produced differences in the magnitude of Pearson's correlations between consecutive saliva samples (r's between 0.27-0.78), and influenced the significance of a sCRP diurnal pattern; two techniques produced statistically higher morning than evening sCRP levels (t(85) = 2.70, p = .01 and t(85) = 2.67, p = .01), whereas six techniques failed to find statistical differences between morning and evening sCRP levels (p's >.05). Varying techniques also produced statistically divergent associations between sCRP and age and depressive symptoms. Results from this study provide evidence for the temporal stability of sCRP among adolescents, show winsorization as an effective OOR data management technique, and highlight the influence of methodological decisions in cleaning salivary biomarker data and the need for consistency within the field.

Developmental Trajectories of Early Life Stress and Trauma: A Narrative Review on Neurobiological Aspects Beyond Stress System Dysregulation

Early life stressors display a high universal prevalence and constitute a major public health problem. Prolonged psychoneurobiological alterations as sequelae of early life stress (ELS) could represent a developmental risk factor and mediate risk for disease, leading to higher physical and mental morbidity rates in later life. ELS could exert a programming effect on sensitive neuronal brain networks related to the stress response during critical periods of development and thus lead to enduring hyper- or hypo-activation of the stress system and altered glucocorticoid signaling. In addition, alterations in emotional and autonomic reactivity, circadian rhythm disruption, functional and structural changes in the brain, as well as immune and metabolic dysregulation have been lately identified as important risk factors for a chronically impaired homeostatic balance after ELS. Furthermore, human genetic background and epigenetic modifications through stress-related gene expression could interact with these alterations and explain inter-individual variation in vulnerability or resilience to stress. This narrative review presents relevant evidence from mainly human research on the ten most acknowledged neurobiological allostatic pathways exerting enduring adverse effects of ELS even decades later (hypothalamic-pituitary-adrenal axis, autonomic nervous system, immune system and inflammation, oxidative stress, cardiovascular system, gut microbiome, sleep and circadian system, genetics, epigenetics, structural, and functional brain correlates). Although most findings back a causal relation between ELS and psychobiological maladjustment in later life, the precise developmental trajectories and their temporal coincidence has not been elucidated as yet. Future studies should prospectively investigate putative mediators and their temporal sequence, while considering the potentially delayed time-frame for their phenotypical expression. Better screening strategies for ELS are needed for a better individual prevention and treatment.

Role of Inflammation in Depression and Treatment Implications

Approximately one third of depressed patients fail to respond to currently available antidepressant therapies. Therefore, new conceptual frameworks are needed to identify pathophysiologic pathways and neurobiological targets for the development of novel treatment strategies. In this regard, recent evidence suggests that inflammation may contribute to symptoms relevant to a number of psychiatric disorders and particularly depression. Numerous studies (including meta-analyses) have found elevated peripheral and central inflammatory cytokines and acute phase proteins in depression. Chronic exposure to increased inflammation is thought to drive changes in neurotransmitters and neurocircuits that lead to depressive symptoms and that may also interfere with or circumvent the efficacy of antidepressants. Indeed, patients with high inflammation have been shown to exhibit poor response to conventional antidepressant therapies. Recent developments in our ability to understand and measure the effects of inflammation on the brain in patients have opened new doors for the testing of novel treatment strategies that target the immune system or its consequences on neurotransmitter systems. Such recent developments in the field of behavioral immunology and their translational implications for the treatment of depression are discussed herein.

Treatment-resistant depression and peripheral C-reactive protein

BACKGROUND

C-reactive protein (CRP) is a candidate biomarker for major depressive disorder (MDD), but it is unclear how peripheral CRP levels relate to the heterogeneous clinical phenotypes of the disorder.AimTo explore CRP in MDD and its phenotypic associations.

METHOD

We recruited 102 treatment-resistant patients with MDD currently experiencing depression, 48 treatment-responsive patients with MDD not currently experiencing depression, 48 patients with depression who were not receiving medication and 54 healthy volunteers. High-sensitivity CRP in peripheral venous blood, body mass index (BMI) and questionnaire assessments of depression, anxiety and childhood trauma were measured. Group differences in CRP were estimated, and partial least squares (PLS) analysis explored the relationships between CRP and specific clinical phenotypes.

RESULTS

Compared with healthy volunteers, BMI-corrected CRP was significantly elevated in the treatment-resistant group (P = 0.007; Cohen's d = 0.47); but not significantly so in the treatment-responsive (d = 0.29) and untreated (d = 0.18) groups. PLS yielded an optimal two-factor solution that accounted for 34.7% of variation in clinical measures and for 36.0% of variation in CRP. Clinical phenotypes most strongly associated with CRP and heavily weighted on the first PLS component were vegetative depressive symptoms, BMI, state anxiety and feeling unloved as a child or wishing for a different childhood.

CONCLUSIONS

CRP was elevated in patients with MDD, and more so in treatment-resistant patients. Other phenotypes associated with elevated CRP included childhood adversity and specific depressive and anxious symptoms. We suggest that patients with MDD stratified for proinflammatory biomarkers, like CRP, have a distinctive clinical profile that might be responsive to second-line treatment with anti-inflammatory drugs.Declaration of interestS.R.C. consults for Cambridge Cognition and Shire; and his input in this project was funded by a Wellcome Trust Clinical Fellowship (110049/Z/15/Z). E.T.B. is employed half time by the University of Cambridge and half time by GlaxoSmithKline; he holds stock in GlaxoSmithKline. In the past 3 years, P.J.C. has served on an advisory board for Lundbeck. N.A.H. consults for GlaxoSmithKline. P.d.B., D.N.C.J. and W.C.D. are employees of Janssen Research &amp; Development, LLC., of Johnson &amp; Johnson, and hold stock in Johnson &amp; Johnson. The other authors report no financial disclosures or potential conflicts of interest.

Inflammation among Children: Evidence of an Immigrant Advantage?

Past research on the immigrant health paradox suggests that children with immigrant parents may have a health advantage over those with U.S.-born parents, especially if the parent is a recent immigrant. Other research emphasizes the social and economic challenges children with immigrant parents face, in part due to disadvantaged social class and racial/ethnic positions. Underlying physiological changes due to chronic stress exposures among children in immigrant families is one potential health disadvantage that may not yet be apparent in traditional health measures. To explore these biological disparities during childhood, I use national biomarker and survey data from NHANES (N=11,866) to evaluate parent nativity and educational status associations with low-grade inflammation, indicated by C-reactive Protein (CRP), in children ages 2-15 years. I find that children with an immigrant parent, and particularly a low-education immigrant parent, have higher CRP, net of birth, BMI and other factors, than children with a U.S. born parent with either a low or higher education. Comparing children with low-educated parents, those with a foreign-born parent have higher predicted CRP. The findings from this study provide new evidence that children living in immigrant families in the U.S. may be facing higher levels of chronic stress exposure, as indicated by the increased risk of low-grade inflammation, than those with U.S.-born parents. The physiological changes related to increased risk of inflammation could set children in immigrant families on pathways towards mental and physical health problems throughout childhood and later in the life course.

Applications of machine learning algorithms to predict therapeutic outcomes in depression: A meta-analysis and systematic review

BACKGROUND

No previous study has comprehensively reviewed the application of machine learning algorithms in mood disorders populations. Herein, we qualitatively and quantitatively evaluate previous studies of machine learning-devised models that predict therapeutic outcomes in mood disorders populations.

METHODS

We searched Ovid MEDLINE/PubMed from inception to February 8, 2018 for relevant studies that included adults with bipolar or unipolar depression; assessed therapeutic outcomes with a pharmacological, neuromodulatory, or manual-based psychotherapeutic intervention for depression; applied a machine learning algorithm; and reported predictors of therapeutic response. A random-effects meta-analysis of proportions and meta-regression analyses were conducted.

RESULTS

We identified 639 records: 75 full-text publications were assessed for eligibility; 26 studies (n=17,499) and 20 studies (n=6325) were included in qualitative and quantitative review, respectively. Classification algorithms were able to predict therapeutic outcomes with an overall accuracy of 0.82 (95% confidence interval [CI] of [0.77, 0.87]). Pooled estimates of classification accuracy were significantly greater (p < 0.01) in models informed by multiple data types (e.g., composite of phenomenological patient features and neuroimaging or peripheral gene expression data; pooled proportion [95% CI] = 0.93[0.86, 0.97]) when compared to models with lower-dimension data types (pooledproportion=0.68[0.62,0.74]to0.85[0.81,0.88]).

LIMITATIONS

Most studies were retrospective; differences in machine learning algorithms and their implementation (e.g., cross-validation, hyperparameter tuning); cannot infer importance of individual variables fed into learning algorithm.

CONCLUSIONS

Machine learning algorithms provide a powerful conceptual and analytic framework capable of integrating multiple data types and sources. An integrative approach may more effectively model neurobiological components as functional modules of pathophysiology embedded within the complex, social dynamics that influence the phenomenology of mental disorders.

Immunocognitive Model of Depression Secondary to Anxiety in Adolescents

There is evidence that anxiety precedes the onset of depression and that rumination contributes to this risk pathway in adolescence. This study examined inflammatory biomarkers as mediators in a risk model of depressive symptoms secondary to anxiety symptoms among adolescents who ruminate. A sample of 140 adolescents (52% female, 54% African American, 40% Caucasian, 6% biracial, mean age at T1 = 16.5 years, SD = 1.2 years) provided blood samples on two visits (T1 and T2; mean time between T1 and T2 = 13.5 months, SD = 5.9 months). Self-report anxiety, depression, and rumination measures were given at T1 and the depression measure was given again at a third visit (T3, mean months since T1 = 26.0 months, SD = 9.0 months). Higher anxiety predicted more interleukin-6, but not more C-reactive protein, for adolescents with high levels of rumination. Moderated mediation analyses (N for analysis after removing cases with missing data and outliers = 86) indicated that interleukin-6, but not C-reactive protein, at T2 mediated the relationship between anxiety symptoms at T1 and depressive symptoms at T3, conditional on rumination. Anxiety and rumination interacted such that, as rumination increased, anxiety predicted greater inflammation and depressive symptoms. These results demonstrate that established cognitive vulnerabilities for the development of depressive symptoms secondary to anxiety symptoms in adolescence might indirectly operate though biological mechanisms such as inflammation. In addition to highlighting risk factors and potential treatment targets for depression, this study suggests a potential biological mechanism underlying the effects of psychotherapies that reduce rumination on negative affect (e.g., cognitive behavioral therapy).

Central neuroimmune activity and depressive-like behavior in response to repeated maternal separation and injection of LPS

Disruption of attachment relations in early life is linked to greater vulnerability to depressive illness at later ages. Evidence suggests this process involves stress-induced activation of central inflammatory factors, though the specific mediators and processes involved are not known. We used a guinea pig model in which effects of maternal separation appear more clearly due to absence of the attachment figure than is the case for other laboratory rodents. Separation in a novel environment on two consecutive days evoked a depressive-like behavioral response that sensitized during a final test 9 days later. At this time, prior separation blunted the response of prostaglandin synthesizing enzymes (COX-2 and mPGES) and chemokines (CXCL-1 and MCP-1) 120 min following injection with lipopolysaccharide and isolation in a novel cage. The blunted response was not associated with a greater plasma cortisol elevation. In addition, injection of saline just prior to isolation at the oldest age elicited small, but significant, elevations in several signaling molecules, particularly at 30 min. These results demonstrate lasting central inflammatory consequences of our separation procedure. However, contrary to expectations, sensitization of depressive-like behavior was not associated with an increase in expression of neuroimmune mediators to inflammatory challenge. Together with earlier findings, the results suggest a multi-step process in which inflammatory response to an initial separation affects downstream mediators to sensitize depressive-like behavior.

Increased neutrophil-lymphocyte ratios in depressive adolescents is correlated with the severity of depression

We aimed to investigate the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescents with major depression. Sixty-seven adolescents and 121 healthy controls were enrolled in the study. The diagnosis was made by using both the Kiddie and Young Adult Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version and the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition. The severity of depressive symptoms was evaluated using the Beck depression inventory (BDI). The neutrophil-lymphocyte ratios of the adolescents with depression were significantly higher than those of the control group, even after adjusting for age, sex, BMI, and BDI scores, whereas there was no significant difference in platelet-lymphocyte ratios. A positive correlation between the severity of depression and neutrophil-lymphocyte ratios and platelet-lymphocyte ratios were determined in the case group. The results of this study may promote the hypothesis that inflammation plays an important role in the etiology of major depression in adolescents.

Identification of depression subtypes and relevant brain regions using a data-driven approach

It is well known that depressive disorder is heterogeneous, yet little is known about its neurophysiological subtypes. In the present study, we identified neurophysiological subtypes of depression related to specific neural substrates. We performed cluster analysis for 134 subjects (67 depressive subjects and 67 controls) using a high-dimensional dataset consisting of resting state functional connectivity measured by functional MRI, clinical questionnaire scores, and various biomarkers. Applying a newly developed, multiple co-clustering method to this dataset, we identified three subtypes of depression that are characterized by functional connectivity between the right Angular Gyrus (AG) and other brain areas in default mode networks, and Child Abuse Trauma Scale (CATS) scores. These subtypes are also related to Selective Serotonin-Reuptake Inhibitor (SSRI) treatment outcomes, which implies that we may be able to predict effectiveness of treatment based on AG-related functional connectivity and CATS.

Imaging the Role of Inflammation in Mood and Anxiety-related Disorders

Background

Studies investigating the impact of a variety of inflammatory stimuli on the brain and behavior have reported evidence that inflammation and release of inflammatory cytokines affect circuitry relevant to both reward and threat sensitivity to contribute to behavioral change. Of relevance to mood and anxiety-related disorders, biomarkers of inflammation such as inflammatory cytokines and acute-phase proteins are reliably elevated in a significant proportion of patients with major depressive disorder (MDD), bipolar disorder, anxiety disorders and post-traumatic stress disorder (PTSD).

Methods

This review summarized clinical and translational work demonstrating the impact of peripheral inflammation on brain regions and neurotransmitter systems relevant to both reward and threat sensitivity, with a focus on neuroimaging studies involving administration of inflammatory stimuli. Recent translation of these findings to further understand the role of inflammation in mood and anxiety-related disorders is also discussed.

Results

Inflammation was consistently found to affect basal ganglia and cortical reward and motor circuits to drive reduced motivation and motor activity, as well as anxiety-related brain regions including amygdala, insula and anterior cingulate cortex, which may result from cytokine effects on monoamines and glutamate. Similar relationships between inflammation and altered neurocircuitry have been observed in MDD patients with increased peripheral inflammatory markers, and such work is on the horizon for anxiety disorders and PTSD.

Conclusion

Neuroimaging effects of inflammation on reward and threat circuitry may be used as biomarkers of inflammation for future development of novel therapeutic strategies to better treat mood and anxiety-related disorders in patients with high inflammation.

Racial-ethnic Disparities in Inflammation: Evidence of Weathering in Childhood?

Building on the weathering hypothesis, we advance health disparities research by assessing racial-ethnic differences in low-grade inflammation, a marker of chronic stress exposure, in young children. Using nationally representative data from the National Health and Nutrition Examination Survey (N = 6,652) and logistic regression, we find an increased risk of low-grade inflammation among Hispanic and African American children compared to white children. The risk of inflammation appears to be stronger for Hispanic and African American children with foreign-born parents compared to children of the same race-ethnicity with U.S.-born parents. Low parental education and elevated child body mass index work as partial mediators of these associations. Our findings suggest the need to understand the psychosocial challenges faced by Hispanic and African American children, particularly, those with foreign-born parents, if we are to make further progress in reducing health disparities.

Early life stress, air pollution, inflammation, and disease: An integrative review and immunologic model of social-environmental adversity and lifespan health

Socially disadvantaged individuals are at greater risk for simultaneously being exposed to adverse social and environmental conditions. Although the mechanisms underlying joint effects remain unclear, one hypothesis is that toxic social and environmental exposures have synergistic effects on inflammatory processes that underlie the development of chronic diseases, including cardiovascular disease, diabetes, depression, and certain types of cancer. In the present review, we examine how exposure to two risk factors that commonly occur with social disadvantage-early life stress and air pollution-affect health. Specifically, we identify neuroimmunologic pathways that could link early life stress, inflammation, air pollution, and poor health, and use this information to propose an integrated, multi-level model that describes how these factors may interact and cause health disparity across individuals based on social disadvantage. This model highlights the importance of interdisciplinary research considering multiple exposures across domains and the potential for synergistic, cross-domain effects on health, and may help identify factors that could potentially be targeted to reduce disease risk and improve lifespan health.

Relationships of Anxiety and Depression with Cardiovascular Health in Youth with Normal Weight to Severe Obesity

OBJECTIVE

To evaluate the relationships of depression and anxiety symptoms with cardiovascular disease (CVD) risk factors and measures of vascular health in youth.

STUDY DESIGN

Participants (n = 202) were 8- to 18-year-olds from a cross-sectional study evaluating cardiovascular health across a wide range of body mass index values (normal weight to severe obesity). CVD risk measurement included blood pressure, fasting lipids, glucose, insulin, carotid artery intima-media thickness, compliance and distensibility, brachial artery flow-mediated dilation, carotid-radial artery pulse wave velocity, body fat percentage, and a metabolic syndrome cluster score. Anxiety and depression symptoms were self-reported on the Screen for Child Anxiety Related Disorders and Center for Epidemiological Studies Depression Scale for Children. Two sets of adjustment variables were used in evaluation of differences between those with and without anxiety or depression symptomatology for the CVD risk factor and vascular outcomes. The first set included adjustment for Tanner stage, sex, and race; the second was additionally adjusted for percent body fat.

RESULTS

Anxiety was not significantly associated with CVD risk factors or vascular health in either model. Depression was associated with high-density lipoprotein cholesterol, triglycerides, and metabolic syndrome cluster score; these relationships were attenuated when accounting for percent body fat.

CONCLUSIONS

When accounting for body fat, we found no clear relationship of self-reported depression or anxiety symptoms with CVD risk factors or vascular health in youth.

Childhood abuse and neglect and physical health at midlife: Prospective, longitudinal evidence

Previous research suggests that the experience of abuse and neglect in childhood has negative implications for physical health in adulthood. Using data from the Minnesota Longitudinal Study of Risk and Adaptation (N = 115), the present research examined the predictive significance of childhood physical abuse, sexual abuse, and physical/cognitive neglect for multilevel assessments of physical health at midlife (age 37-39 years), including biomarkers of cardiometabolic risk, self-reports of quality of health, and a number of health problems. Analyses revealed that childhood physical/cognitive neglect, but not physical or sexual abuse, predicted all three health outcomes in middle adulthood, even when controlling for demographic risk factors and adult health maintenance behaviors. We discuss possible explanations for the unique significance of neglect in this study and suggest future research that could clarify previous findings regarding the differential impact of different types of abuse and neglect on adult health.

When inflammation and depression go together: The longitudinal effects of parent-child relationships

Parent-child relationships have long-term effects on health, particularly later inflammation and depression. We hypothesized that these effects would be mediated by later romantic partner relationships and elevated stressors in young adulthood, helping promote chronic, low grade, inflammation as well as depressive symptoms, and driving their covariation. It has been proposed recently that youth experiencing harsher parenting may also develop a stronger association between inflammation and depressive symptoms in adulthood and altered effects of stressors on outcomes. In the current investigation, we test these ideas using an 18-year longitudinal study of N = 413 African American youth that provides assessment of the parent-child relationship (at age 10), pro-inflammatory cytokine profile and depressive symptoms (at age 28), and potential mediators in early young adulthood (assessed at ages 21 and 24). As predicted, the effect of harsher parent-child relationships (age 10) on pro-inflammatory state and increased depressive symptoms at age 28 were fully mediated through young adult stress and romantic partner relationships. In addition, beyond these mediated effects, parent-child relationships at age 10 moderated the concurrent association between inflammation and depressive symptoms, as well as the prospective association between romantic partner relationships and inflammation, and resulted in substantially different patterns of indirect effects from young adult mediators to outcomes. The results support theorizing that the association of depression and inflammation in young adulthood is conditional on earlier parenting, and suggest incorporating this perspective into models predicting long-term health outcomes.

The microbiome as a novel paradigm in studying stress and mental health

At the intersection between neuroscience, microbiology, and psychiatry, the enteric microbiome has potential to become a novel paradigm for studying the psychobiological underpinnings of mental illness. Several studies provide support for the view that the enteric microbiome influences behavior through the microbiota-gut-brain axis. Moreover, recent findings are suggestive of the possibility that dysregulation of the enteric microbiota (i.e., dysbiosis) and associated bacterial translocation across the intestinal epithelium may be involved in the pathophysiology of stress-related psychiatric disorders, particularly depression. The current article reviews preliminary evidence linking the enteric microbiota and its metabolites to psychiatric illness, along with separate lines of empirical inquiry on the potential involvement of psychosocial stressors, proinflammatory cytokines and neuroinflammation, the hypothalamic-pituitary-adrenal axis, and vagal nerve activation, respectively, in this relationship. Finally, and drawing on these independent lines of research, an integrative conceptual model is proposed in which stress-induced enteric dysbiosis and intestinal permeability confer risk for negative mental health outcomes through immunoregulatory, endocrinal, and neural pathways. (PsycINFO Database Record

Minority stress and leukocyte gene expression in sexual minority men living with treated HIV infection

Sexual minority (i.e., non-heterosexual) individuals experience poorer mental and physical health, accounted for in part by the additional burden of sexual minority stress occurring from being situated in a culture favoring heteronormativity. Informed by previous research, the purpose of this study was to identify the relationship between sexual minority stress and leukocyte gene expression related to inflammation, cancer, immune function, and cardiovascular function. Sexual minority men living with HIV who were on anti-retroviral medication, had viral load < 200 copies/mL, and had biologically confirmed, recent methamphetamine use completed minority stress measures and submitted blood samples for RNA sequencing on leukocytes. Differential gene expression and pathway analyses were conducted comparing those with clinically elevated minority stress (n = 18) and those who did not meet the clinical cutoff (n = 20), covarying reactive urine toxicology results for very recent stimulant use. In total, 90 differentially expressed genes and 138 gene set pathways evidencing 2-directional perturbation were observed at false discovery rate (FDR) < 0.10. Of these, 41 of the differentially expressed genes and 35 of the 2-directionally perturbed pathways were identified as functionally related to hypothesized mechanisms of inflammation, cancer, immune function, and cardiovascular function. The neuroactive-ligand receptor pathway (implicated in cancer development) was identified using signaling pathway impact analysis. Our results suggest several potential biological pathways for future work investigating the relationship between sexual minority stress and health.

Annual Research Review: Early adversity, the hypothalamic-pituitary-adrenocortical axis, and child psychopathology

BACKGROUND

Research on early adversity, stress biology, and child development has grown exponentially in recent years.

FINDINGS

We review the current evidence for the hypothalamic-pituitary-adrenocortical (HPA) axis as a stress-mediating mechanism between various forms of childhood adversity and psychopathology. We begin with a review of the neurobiology of the axis and evidence for relations between early adversity-HPA axis activity and HPA axis activity-psychopathology, as well as discuss the role of regulatory mechanisms and sensitive periods in development.

CONCLUSIONS

We call attention to critical gaps in the literature to highlight next steps in this research including focus on developmental timing, sex differences, stress buffering, and epigenetic regulation. A better understanding of individual differences in the adversity-HPA axis-psychopathology associations will require continued work addressing how multiple biological and behavioral systems work in concert to shape development.

A preclinical perspective on the enhanced vulnerability to Alzheimer's disease after early-life stress

Stress experienced early in life (ES), in the form of childhood maltreatment, maternal neglect or trauma, enhances the risk for cognitive decline in later life. Several epidemiological studies have now shown that environmental and adult life style factors influence AD incidence or age-of-onset and early-life environmental conditions have attracted attention in this respect. There is now emerging interest in understanding whether ES impacts the risk to develop age-related neurodegenerative disorders, and their severity, such as in Alzheimer's disease (AD), which is characterized by cognitive decline and extensive (hippocampal) neuropathology. While this might be relevant for the identification of individuals at risk and preventive strategies, this topic and its possible underlying mechanisms have been poorly studied to date. In this review, we discuss the role of ES in modulating AD risk and progression, primarily from a preclinical perspective. We focus on the possible involvement of stress-related, neuro-inflammatory and metabolic factors in mediating ES-induced effects on later neuropathology and the associated impairments in neuroplasticity. The available studies suggest that the age of onset and progression of AD-related neuropathology and cognitive decline can be affected by ES, and may aggravate the progression of AD neuropathology. These relevant changes in AD pathology after ES exposure in animal models call for future clinical studies to elucidate whether stress exposure during the early-life period in humans modulates later vulnerability for AD.

Childhood victimization and inflammation in young adulthood: A genetically sensitive cohort study

OBJECTIVE

Childhood victimization is an important risk factor for later immune-related disorders. Previous evidence has demonstrated that childhood victimization is associated with elevated levels of inflammation biomarkers measured decades after exposure. However, it is unclear whether this association is (1) already detectable in young people, (2) different in males and females, and (3) confounded by genetic liability to inflammation. Here we sought to address these questions.

METHOD

Participants were 2232 children followed from birth to age 18years as part of the Environmental Risk (E-Risk) Longitudinal Twin Study. Childhood victimization was measured prospectively from birth to age 12years. Inflammation was measured through C-reactive protein (CRP) levels in dried blood spots at age 18years. Latent genetic liability for high inflammation levels was assessed through a twin-based method.

RESULTS

Greater exposure to childhood victimization was associated with higher CRP levels at age 18 (serum-equivalent means were 0.65 in non-victimized Study members, 0.74 in those exposed to one victimization type, and 0.81 in those exposed to poly-victimization; p=0.018). However, this association was driven by a significant association in females (serum-equivalent means were 0.75 in non-victimized females, 0.87 in those exposed to one type of victimization, and 1.19 in those exposed to poly-victimization; p=0.010), while no significant association was observed in males (p=0.19). Victimized females showed elevated CRP levels independent of latent genetic influence, as well as childhood socioeconomic status, and waist-hip ratio and body temperature at the time of CRP assessment.

CONCLUSION

Childhood victimization is associated with elevated CRP levels in young women, independent of latent genetic influences and other key risk factors. These results strengthen causal inference about the effects of childhood victimization on inflammation levels in females by accounting for potential genetic confounding.

Nested positive feedback loops in the maintenance of major depression: An integration and extension of previous models

Several theories of Major Depressive Disorder (MDD) have previously been proposed, focusing largely on either a psychological (i.e., cognitive/affective), biological, or neural/computational level of description. These theories appeal to somewhat distinct bodies of work that have each highlighted separate factors as being of considerable potential importance to the maintenance of MDD. Such factors include a range of cognitive/attentional information-processing biases, a range of structural and functional brain abnormalities, and also dysregulation within the autonomic, endocrine, and immune systems. However, to date there have been limited efforts to integrate these complimentary perspectives into a single multi-level framework. Here we review previous work in each of these MDD research domains and illustrate how they can be synthesized into a more comprehensive model of how a depressive episode is maintained. In particular, we emphasize how plausible (but insufficiently studied) interactions between the various MDD-related factors listed above can lead to a series of nested positive feedback loops, which are each capable of maintaining an individual in a depressive episode. We also describe how these different feedback loops could be active to different degrees in different individual cases, potentially accounting for heterogeneity in both depressive symptoms and treatment response. We conclude by discussing how this integrative model might extend understanding of current treatment mechanisms, and also potentially guide the search for markers to inform treatment selection in individual cases.

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.