The role of mild stressors in children's cognition and inflammation: positive and negative impacts depend on timing of exposure

Although the impact of stressful life events (SLEs) on mental health is well-established, the research on the impact of such stressors on cognitive outcomes has produced mixed results. Arguably, the timing and severity of exposure may play a key role. In this study, we shed light on the relationship between timing of exposure to relatively minor SLEs and cognitive ability in children, while taking into account the role of a plausible biological mediator: inflammation. Using data from the Avon Longitudinal Study of Parents and Children, a general population birth cohort, we explored the role of relatively minor SLEs, experienced during two crucial developmental stages: up to transition to school (1-4.5 years) and up to transition to puberty (5.5-8.5 years). We then tested if they may impact differently on inflammatory markers (serum C-reactive protein [CRP] and interleukin 6 [IL-6]) at age 9 and general intelligence, measured with the Wechsler Abbreviated Scale of Intelligence at age 15. Data (n = 4,525) were analyzed using path analysis while controlling for covariates. We found that when relatively minor stressful events were experienced up to transition to school they were significantly associated with higher IQ at age 15, whereas when experienced up to transition to puberty they were significantly associated with higher levels of IL-6 at age 9. Results were robust to adjustment for relevant covariates, including IQ at age 8. Mild stressors in childhood may result in positive (i.e., improved cognition) or negative (i.e., inflammation) outcomes depending on the timing of exposure.

Endotoxin-Induced Physiological and Psychological Sickness Responses in Healthy Humans: Insights into the Post-Acute Phase

INTRODUCTION

Experimental endotoxemia is a translational model of systemic inflammation that has contributed significantly to our current understanding of sickness behavior and inflammation-associated depression. Previous studies using this model revealed a strong association between cytokine levels, endocrine changes, and psychological sickness symptoms during the acute phase of inflammation. The objective of this randomized, double-blind, placebo-controlled crossover study was to gain insight into potential post-acute physiological and psychological consequences of endotoxin administration that may either persist or newly emerge between 24 and 72 h after injection. The main focus was on associations between serum levels of C-reactive protein (CRP) and affective symptoms as well as alterations in diurnal cortisol profile, the two key features of inflammation-associated depression.

METHODS

Healthy male volunteers (N = 18) received an injection of either endotoxin (0.8 ng/kg) or placebo on two separate but otherwise identical study days, 7 days apart. Blood and saliva samples were collected during acute and post-acute phases after injection to measure blood inflammatory markers (interleukin [IL]-6, IL-1 receptor antagonist [ra], CRP) and salivary cortisol levels. In addition, participants completed a comprehensive battery of questionnaires to assess physical and psychological sickness symptoms.

RESULTS

Endotoxin treatment induced a short-time rise in plasma IL-6 and a longer increase in IL-1ra. The increase in serum CRP was delayed compared to cytokines, peaking at 24 h and gradually decreasing until 72 h after injection. The inflammatory response was accompanied by bodily and psychological sickness symptoms which occurred only in the acute phase, whereas none of the symptoms persisted or recurred in the post-acute phase. Salivary cortisol levels were significantly increased during the acute phase and exhibited pronounced circadian changes. However, no significant differences in diurnal cortisol profiles were observed between placebo and endotoxin conditions on the days after treatment.

CONCLUSION

Our findings suggest that CRP, which is elevated in patients with inflammation-associated depression, does not appear to be responsible for depressive symptomatology. Moreover, a single inflammatory episode is not sufficient to alter diurnal cortisol profiles, as observed in inflammation-associated depression. In addition, the absence of persistent lipopolysaccharide-induced psychological and physiological changes beyond the acute phase further supports the safety of endotoxin administration in humans.

Patterns of adolescent perceived social support and inflammation in adulthood within major racial groups: Findings from a longitudinal, nationally representative sample

Inflammation, the body's protective response to injury and infection, plays a critical role in physical and mental health outcomes. Elevated chronic inflammation is implicated as a predictor of disease and all-cause mortality and is linked with several psychological disorders. Given that social support is associated with lower rates of mortality and psychopathology, the links between inflammation and social support are well-studied. However, there are many significant gaps related to both the specificity and generalizability of extant findings. There is a paucity of research on the association between social support and inflammation within different racial groups. Additionally, more research is warranted to understand whether social support from different sources uniquely contributes to inflammation, above and beyond other sources of support. Thus, the current study examined whether perceived emotional social support during adolescence predicted inflammation during adulthood within several racial groups. Participants (n = 3,390) were drawn from the National Longitudinal Study of Adolescent to Adult Health (Add Health), identified as either Asian, Black, Latinx, White, or Multiracial, and had complete data on study variables. Consistent with our hypotheses and previous research, greater perceived support during adolescence was associated with lower inflammation during adulthood, but only for White participants. Contrastingly, greater perceived support during adolescence was associated with higher inflammation during adulthood for individuals who identified as Asian, Latinx, Black, or Multiracial. Furthermore, patterns of social support and inflammation within each racial group varied by relationship type. These results highlight the importance of studying relationship processes and health outcomes within racial groups to understand their unique, lived experiences.

Mediators of inflammation at the maternal-fetal interface are altered by SARS-CoV-2 infection and pandemic stress

PROBLEM

It is now recognized that SARS-CoV-2 infection and pandemic-related stress impacts maternal health. However, their effects at the maternal-fetal interface are still debated.

METHOD OF STUDY

We recruited 199 women between March 2020 and July 2021, 79 SARS-CoV-2+ and 120 negative (the latter exposed to pandemic stress only). We also included 40 historic controls (i.e. pre-pandemic uncomplicated pregnancies recruited before March 2020). Placental samples were collected for protein and histological analysis.

RESULTS

The majority of SARS-CoV-2+ women were multiethnic, had higher pre-pregnancy BMI and elevated preterm birth rate (17%) vs SARS-CoV-2- or historic control. Placental inflammatory profile revealed increased IL-1Ra and CRP, independently of SARS-CoV-2 status, whilst MCP-1, IL-6 and IFNγ were elevated in the negative, but pandemic stress-exposed, group. These changes were predominant in placentas with inflammatory lesions on histopathological analysis. Furthermore, we observed elevated immune cells (CD45+) in placentas from SARS-CoV-2+ and negative pregnancies vs historic controls, even when individuals with pregnancy complications were excluded.

CONCLUSIONS

Placental inflammatory profiles differed between SARS-CoV-2 statuses, namely exposed to pandemic stress +/- SARS-CoV-2 infection. This highlights the need to understand the differences between the effects of pandemic-related stress and the added burden of SARS-CoV-2 infection on placental health.

Evolutionary Aspects of Diverse Microbial Exposures and Mental Health: Focus on "Old Friends" and Stress Resilience

The prevalence of inflammatory disease conditions, including allergies, asthma, and autoimmune disorders, increased during the latter half of the twentieth century, as societies transitioned from rural to urban lifestyles. A number of hypotheses have been put forward to explain the increasing prevalence of inflammatory disease in modern urban societies, including the hygiene hypothesis and the "Old Friends" hypothesis. In 2008, Rook and Lowry proposed, based on the evidence that increased inflammation was a risk factor for stress-related psychiatric disorders, that the hygiene hypothesis or "Old Friends" hypothesis may be relevant to psychiatric disorders. Since then, it has become more clear that chronic low-grade inflammation is a risk factor for stress-related psychiatric disorders, including anxiety disorders, mood disorders, and trauma- and stressor-related disorders, such as posttraumatic stress disorder (PTSD). Evidence now indicates that persons raised in modern urban environments without daily contact with pets, relative to persons raised in rural environments in proximity to farm animals, respond with greater systemic inflammation to psychosocial stress. Here we consider the possibility that increased inflammation in persons living in modern urban environments is due to a failure of immunoregulation, i.e., a balanced expression of regulatory and effector T cells, which is known to be dependent on microbial signals. We highlight evidence that microbial signals that can drive immunoregulation arise from phylogenetically diverse taxa but are strain specific. Finally, we highlight Mycobacterium vaccae NCTC 11659, a soil-derived bacterium with anti-inflammatory and immunoregulatory properties, as a case study of how single strains of bacteria might be used in a psychoneuroimmunologic approach for prevention and treatment of stress-related psychiatric disorders.

Specific Associations Between Type of Childhood Abuse and Elevated C-Reactive Protein in Young Adult Psychiatric Rehabilitation Participants

BACKGROUND

Early-life adversity such as childhood emotional, physical, and sexual trauma is associated with later-life psychiatric and chronic medical conditions, including elevated inflammatory markers. Although previous research suggests a role for chronic inflammatory dysfunctions in several disease etiologies, specific associations between childhood trauma types and later-life inflammation and health status are poorly understood.

METHODS

We studied patients (n = 280) admitted to a psychiatric rehabilitation center. Self-reported histories of childhood emotional, physical, and sexual trauma were collected with a standard instrument. At the time of admission, we also assessed individuals' body mass index and collected blood samples used to examine inflammatory marker C-reactive protein (CRP) levels.

RESULTS

The prevalence of all 3 types of abuse was relatively high at 21% or more. Fifty percent of the sample had elevations in CRP, with clinically significant elevations in 26%. We found that compared with a history of emotional or physical abuse, a history of childhood sexual trauma was more specifically associated with elevated CRP. This result held up when using linear regressions to examine the contribution of body mass index.

LIMITATION

Our sample was relatively young, with an average age of 27.2 years and minimal representation of ethnic and racial minority participants.

CONCLUSION

Relative to childhood emotional and physical trauma, childhood sexual trauma may lead to elevated inflammatory responses, as confirmed in our finding of an association between CRP and sexual abuse. Future studies need to assess the causal link between childhood sexual trauma and poorer health outcomes later in life.

Longitudinal associations between salivary cortisol to C-reactive protein ratios and psychological well-being in Chinese adults

BACKGROUND

Salivary C-reactive protein (CRP) could be a viable biomarker of inflammation and has been associated with stress outcomes. The hypothalamic-pituitary-adrenal axis can modulate stress-related inflammation. This study aimed to evaluate the interaction effects of immune-endocrine markers on psychological outcomes.

METHODS

The study participants were 52 healthy Chinese adults who collected 10 saliva samples over 2 consecutive days at baseline. The participants completed validated measures on anxiety, depression, positive affect, and sleep disturbance at baseline and 1 month later. The stability and diurnal patterns of salivary cortisol and CRP were investigated via paired t-tests and repeated-measures analyses of variance. Regression analysis was used to examine the longitudinal associations between immune-endocrine markers and their interactions (cortisol [Cort]: morning CRP [CRP_morn] and Cort:CRP_even) and psychological measures.

RESULTS

Salivary cortisol and CRP displayed satisfactory stability over 2 consecutive days and diurnal patterns of abrupt and gradual decline during the day, respectively. Controlling for baseline psychological measures and confounding variables, Cort_morn and diurnal cortisol slope was significantly and negatively associated with anxiety symptoms and positive affect 1 month later, respectively. Cort:CRP_even and Cort:CRP_morn was significantly and positively associated with depressive symptoms and sleep disturbance 1 month later, respectively.

CONCLUSION

These findings offer initial support for the prognostic utility of salivary cortisol and CRP and their balance as determinants of psychological health in healthy adults.

Gut-derived systemic inflammation as a driver of depression in chronic liver disease

Depression and chronic liver disease (CLD) are important causes of disability, morbidity and mortality worldwide and their prevalence continues to rise. The rate of depression in CLD is high compared to that of the general population and is comparable to the increased rates observed in other medical comorbidities and chronic inflammatory conditions. Notably, a comorbid diagnosis of depression has a detrimental effect on outcomes in cirrhosis. Systemic inflammation is pivotal in cirrhosis-associated immune dysfunction - a phenomenon present in advanced CLD (cirrhosis) and implicated in the development of complications, organ failure, disease progression, increased infection rates and poor outcome. The presence of systemic inflammation is also well-documented in a cohort of patients with depression; peripheral cytokine signals can result in neuroinflammation, behavioural change and depressive symptoms via neural mechanisms, cerebral endothelial cell and circumventricular organ signalling, and peripheral immune cell-to-brain signalling. Gut dysbiosis has been observed in both patients with cirrhosis and depression. It leads to intestinal barrier dysfunction resulting in increased bacterial translocation, in turn activating circulating immune cells, leading to cytokine production and systemic inflammation. A perturbed gut-liver-brain axis may therefore explain the high rates of depression in patients with cirrhosis. The underlying mechanisms explaining the critical relationship between depression and cirrhosis remain to be fully elucidated. Several other psychosocial and biological factors are likely to be involved, and therefore the cause is probably multifactorial. However, the role of the dysfunctional gut-liver-brain axis as a driver of gut-derived systemic inflammation requires further exploration and consideration as a target for the treatment of depression in patients with cirrhosis.

GR/NF-κB signaling pathway regulates hippocampal inflammatory responses in diabetic rats with chronic unpredictable mild stress

Clinical studies have shown that diabetes can present with underlying depression, and a combination of the two can lead to emotional, memory and cognitive disorders, closely associated with hippocampal neuroinflammation. However, the mechanism underlying the development of hippocampal neuroinflammation under the above condition remains elusive. The aims of this study were to explore the pathogenesis of diabetes combined with depression, and the effect of dexamethasone (Dex), a glucocorticoid receptor (GR) agonist, on hippocampal neuroinflammation in diabetic rats with chronic unpredictable mild stress (CUMS). Therefore, rats were intragastrically fed on a high-fat diet (10% cholesterol 10 ml/kg) for 14 days and thereafter injected with 38 mg/kg of streptozotocin on the 15th day to induce diabetes. Dex treatment of the diabetic and CUMS rats ameliorated the depression-associated behavior in the respective rats. Apart from enhanced depressive behavior, diabetes-depressed condition also up-regulated the expression of hippocampus microglia chemokine Ⅰ receptor (CX3CR1) and secretion of several pro-inflammatory factors, in particular, interleukin 1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor - α (TNF-α). Hematoxylin-eosin staining revealed inflammatory damages in the hippocampus. Western blot analysis further revealed repression of GR proteins converse to the nuclear factor kappa-B (NF-κB) proteins, which were up-regulated. Intriguingly, Dex reversed the above events by inhibiting inflammatory reactions in the hippocampus. Consequently, played an antidepressant effect in diabetic and CUMS model rats. Overall, findings of this research suggest that the physiopathology of diabetes with stress cormobity are mediated by inflammatory reactions in the hippocampus. In particular, the responses are associated with regulation of GR/NF-κB signaling pathway.

Postviral Depression

A previously healthy 68-year-old man rapidly developed a severe melancholic depression following influenza infection. There is an evolving understanding of the complex and possibly bidirectional relationship between depression and inflammation. We review the literature concerning this relationship in the context of viral infection and discuss possible implications for treatment.

Lipopolysaccharide does not alter behavioral response to successive negative contrast in mice

BACKGROUND

Reduced motivation is one of the main symptomatic features of inflammation-induced depression. However, the exact nature of inflammation-induced alterations in motivation remains to be fully defined. As inflammation has been shown to increase sensitivity to negative stimuli, the present series of experiments was initiated to determine whether systemic inflammation induced by infra-septic doses of lipopolysaccharide (LPS) in mice influences consummatory and instrumental responding to successive negative contrast.

METHODS

Successive negative contrast was operationally defined by a shift to a lower value reward than the one mice were trained with. Mice were trained to drink a high sucrose concentration solution and exposed to an acute shift to a lower concentration of sucrose. In another series of experiments, mice were trained to nose poke for chocolate pellets according to a fixed reinforcement schedule 10 (10 nose pokes for the food reinforcement) and exposed to a shift to a lower reward value (decreased number of chocolate pellets or replacement of chocolate pellets by less preferred grain pellets). Lipopolysaccharide (LPS) was administered at the dose of 0.33 1 mg/kg 24 h before the shift.

RESULTS

Mice trained to drink a high sucrose concentration responded to the shift in reward value by a reduction in the volume of sucrose consumed and a decrease in lick numbers and bout durations. Mice trained to nose poke for chocolate pellets responded to the shift by alterations in their total number of nose pokes. In both conditions, LPS had no consistent effect on the response to the shift in reward value.

CONCLUSIONS

These findings indicate a high variability in the effects of LPS on successive negative contrast and fail to provide evidence in favor of the hypothesis that LPS increases sensitivity to decreases in expected rewards.

Pathogen disgust sensitivity protects against infection in a high pathogen environment

Disgust is hypothesized to be an evolved emotion that functions to regulate the avoidance of pathogen-related stimuli and behaviors. Individuals with higher pathogen disgust sensitivity (PDS) are predicted to be exposed to and thus infected by fewer pathogens, though no studies have tested this directly. Furthermore, PDS is hypothesized to be locally calibrated to the types of pathogens normally encountered and the fitness-related costs and benefits of infection and avoidance. Market integration (the degree of production for and consumption from market-based economies) influences the relative costs/benefits of pathogen exposure and avoidance through sanitation, hygiene, and lifestyle changes, and is thus predicted to affect PDS. Here, we examine the function of PDS in disease avoidance, its environmental calibration, and its socioecological variation by examining associations among PDS, market-related lifestyle factors, and measures of bacterial, viral, and macroparasitic infection at the individual, household, and community levels. Data were collected among 75 participants (ages 5 to 59 y) from 28 households in three Ecuadorian Shuar communities characterized by subsistence-based lifestyles and high pathogen burden, but experiencing rapid market integration. As predicted, we found strong negative associations between PDS and biomarkers of immune response to viral/bacterial infection, and weaker associations between PDS and measures of macroparasite infection, apparently mediated by market integration-related differences. We provide support for the previously untested hypothesis that PDS is negatively associated with infection, and document variation in PDS indicative of calibration to local socioeconomic conditions. More broadly, findings highlight the importance of evolved psychological mechanisms in human health outcomes.

Early-Life Stress Modulates Gut Microbiota and Peripheral and Central Inflammation in a Sex-Dependent Manner

Recent studies have reported that changes in gut microbiota composition could induce neuropsychiatric problems. In this study, we investigated alterations in gut microbiota induced by early-life stress (ELS) in rats subjected to maternal separation (MS; 6 h a day, postnatal days (PNDs) 1-21), along with changes in inflammatory cytokines and tryptophan-kynurenine (TRP-KYN) metabolism, and assessed the differences between sexes. High-throughput sequencing of the bacterial 16S rRNA gene showed that the relative abundance of the Bacteroides genus was increased and that of the Lachnospiraceae family was decreased in the feces of MS rats of both sexes (PND 56). By comparison, MS increased the relative abundance of the Streptococcus genus and decreased that of the Staphylococcus genus only in males, whereas the abundance of the Sporobacter genus was enhanced and that of the Mucispirillum genus was reduced by MS only in females. In addition, the levels of proinflammatory cytokines were increased in the colons (IFN-γ and IL-6) and sera (IL-1β) of the male MS rats, together with the elevation of the KYN/TRP ratio in the sera, but not in females. In the hippocampus, MS elevated the level of IL-1β and the KYN/TRP ratio in both male and female rats. These results indicate that MS induces peripheral and central inflammation and TRP-KYN metabolism in a sex-dependent manner, together with sex-specific changes in gut microbes.

Inflammation and depressive phenotypes: evidence from medical records from over 12 000 patients and brain morphology

BACKGROUND

Preclinical and human studies suggest an association between chronic inflammation and the development of depressive behaviors. This is proposed to occur through downstream effects of inflammatory cytokines on neuroplasticity, neurogenesis and neurotransmitter function, although the neural correlates remain poorly understood in humans.

METHODS

In Study 1, structural magnetic resonance imaging and serum inflammatory cytokine data were analyzed from 53 psychiatrically healthy female participants. Correlational analyses were conducted between interleukin-6 (IL-6) and volume in a priori regions implicated in the pathophysiology of major depressive disorder (MDD). In Study 2, medical data [including serum inflammatory acute phase reactants (C-reactive protein)] were analyzed for 12 589 participants. Participants were classified as having (n = 2541) v. not having (n = 10 048) probable lifetime MDD using phenotypes derived using machine-learning approaches. Non-parametric analyses compared inflammation between groups, whereas regression analyses probed whether inflammation predicted probable MDD classification while accounting for other variables.

RESULTS

In Study 1, significant negative correlations emerged between IL-6 and hippocampal, caudate, putamen and amygdalar volume. In Study 2, the MDD group showed a higher probability of elevated inflammation than the non-MDD group. Moreover, elevated inflammation was a significant predictor of probable MDD classification.

CONCLUSIONS

Findings indicate that inflammation is cross-sectionally related to reduced volume in brain regions implicated in MDD phenotypes among a sample of psychiatrically healthy women, and is associated with the presence of probable MDD in a large clinical dataset. Future investigations may identify specific inflammatory markers predicting first MDD onset.

Using network analysis to examine links between individual depressive symptoms, inflammatory markers, and covariates

BACKGROUND

Studies investigating the link between depressive symptoms and inflammation have yielded inconsistent results, which may be due to two factors. First, studies differed regarding the specific inflammatory markers studied and covariates accounted for. Second, specific depressive symptoms may be differentially related to inflammation. We address both challenges using network psychometrics.

METHODS

We estimated seven regularized Mixed Graphical Models in the Netherlands Study of Depression and Anxiety (NESDA) data (N = 2321) to explore shared variances among (1) depression severity, modeled via depression sum-score, nine DSM-5 symptoms, or 28 individual depressive symptoms; (2) inflammatory markers C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α); (3) before and after adjusting for sex, age, body mass index (BMI), exercise, smoking, alcohol, and chronic diseases.

RESULTS

The depression sum-score was related to both IL-6 and CRP before, and only to IL-6 after covariate adjustment. When modeling the DSM-5 symptoms and CRP in a conceptual replication of Jokela et al., CRP was associated with 'sleep problems', 'energy level', and 'weight/appetite changes'; only the first two links survived covariate adjustment. In a conservative model with all 38 variables, symptoms and markers were unrelated. Following recent psychometric work, we re-estimated the full model without regularization: the depressive symptoms 'insomnia', 'hypersomnia', and 'aches and pain' showed unique positive relations to all inflammatory markers.

CONCLUSIONS

We found evidence for differential relations between markers, depressive symptoms, and covariates. Associations between symptoms and markers were attenuated after covariate adjustment; BMI and sex consistently showed strong relations with inflammatory markers.

Impact of Acute and Chronic Stress on Thrombosis in Healthy Individuals and Cardiovascular Disease Patients

Psychological stress induces different alterations in the organism in order to maintain homeostasis, including changes in hematopoiesis and hemostasis. In particular, stress-induced hyper activation of the autonomic nervous system and hypothalamic–pituitary–adrenal axis can trigger cellular and molecular alterations in platelets, coagulation factors, endothelial function, redox balance, and sterile inflammatory response. For this reason, mental stress is reported to enhance the risk of cardiovascular disease (CVD). However, contrasting results are often found in the literature considering differences in the response to acute or chronic stress and the health condition of the population analyzed. Since thrombosis is the most common underlying pathology of CVDs, the comprehension of the mechanisms at the basis of the association between stress and this pathology is highly valuable. The aim of this work is to give a comprehensive review of the studies focused on the role of acute and chronic stress in both healthy individuals and CVD patients, focusing on the cellular and molecular mechanisms underlying the relationship between stress and thrombosis.

IL-33 enhances macrophage release of IL-1β and promotes pain and inflammation in gouty arthritis

OBJECTIVE

To investigate the role of IL-33 in gouty arthritis.

MATERIAL

174 Balb/c (wild-type) and 54 ST2^-/- mice were used in this study. In vitro experiments were conducted in bone marrow-derived macrophages (BMDMs). Synovial fluid samples from gouty arthritis (n = 7) and osteoarthritis (n = 8) hospital patients were used to measure IL-33 and sST2 levels.

METHODS

Gout was induced by injection of monosodium urate (MSU) crystals in the knee joint of mice. Pain was determined using the electronic von Frey and static weight bearing. Neutrophil recruitment was determined by H&E staining, Rosenfeld staining slides, and MPO activity. ELISA was used for cytokine and sST2 measurement. The priming effect of IL-33 was determined in BMDM.

RESULTS

Synovial fluid of gout patients showed higher IL-33 levels and neutrophil counts than osteoarthritis patients. In mice, the absence of ST2 prevented mechanical pain, knee joint edema, neutrophil recruitment to the knee joint, and lowered IL-1β and superoxide anion levels. In macrophages, IL-33 enhanced the release of IL-1β and TNF-α, and BMDMs from ST2^-/- showed reduced levels of these cytokines after stimulus with MSU crystals.

CONCLUSION

IL-33 mediates gout pain and inflammation by boosting macrophages production of cytokines upon MSU crystals stimulus.

Hypothalamus-pituitary-adrenal axis imbalance and inflammation contribute to sex differences in separation- and restraint-induced depression

Whether social contact contributes to the underlying mechanisms of depression and the observed sex differences is unclear. In this study, we subjected young male and female mice to separation- and restraint-induced stress for 4 weeks and assessed behaviors, neurotransmitter levels, hormones, and inflammatory cytokines. Results showed that, compared with controls, male mice exposed to stress displayed significant decreases in body weight and sucrose preference after 1 week. In the fourth week, they exhibited a higher degree of anxiety (open field test) and depressive-like behavior (forced swim test). Moreover, the males showed significant decreases in monoamine neurotransmitters, including norepinephrine and dopamine in striatum, and an increase in pro-inflammatory cytokines, such as tumor necrosis factor α and interleukin 1β in serum. In contrast, females showed persistent loss of weight during stress and displayed significant decreases in sucrose preference after stress. Importantly, the females but not males showed activation of the hypothalamus-pituitary-adrenal (HPA) axis, with significantly higher levels adrenocorticotropic hormone. Additionally, mRNA level of c-fos and AVP showed there was significant interaction between stress and sex. Finally, we conclude that an imbalance of the HPA axis and inflammation might be important contributors to sex differences in separation/restraint-induced depressive behavior and that changes might be mediated by c-fos and AVP.

Health-related quality of life in patients with immune mediated inflammatory diseases: A cross-sectional, multidisciplinary study

Immune mediated inflammatory diseases (IMIDs) have similarities in pathophysiology and treatment. Not much is known, however, about health-related quality of life (HR-QoL) in IMIDs. We assessed and compared HR-QoL, using the validated EuroQoL 5-dimensions 5-levels questionnaire, in an observational cohort comprising 530 patients (67.5% female, mean age 49 years (95% CI 35.9-50.9), mean disease duration 31.0 months (95% CI 27.2-34.8)), with the following IMIDs: connective tissue diseases (32.6%), uveitis (20.8%), inflammatory arthritis (17.7%), psoriasis (15.5%), vasculitis (6.2%), primary antiphospholipid syndrome (4.2%), and autoinflammatory diseases (2.8%). Patients used either no anti-inflammatory therapy (31.5%), monotherapy (28.7%), or a combination of anti-inflammatory drugs (39.8%). The mean HR-QoL utility score was 0.75 (95% CI 0.72-0.78). Multinominal logistic regression analysis showed a statistically significant association between a very low HR-QoL (utility score (<0.70)) and female sex, rheumatological IMID or psoriasis, smoking or having smoked in the past, and current biological disease modifying anti-rheumatic drugs use.

Behavioral pharmacology of the mixed-action delta-selective opioid receptor agonist BBI-11008: studies on acute, inflammatory and neuropathic pain, respiration, and drug self-administration

RATIONALE AND OBJECTIVES

The present study characterized the behavioral pharmacology of a novel, mixed-action delta-selective (78:1) opioid receptor agonist, BBI-11008. This glycopeptide drug candidate was tested in assays assessing antinociception (acute, inflammatory, and neuropathic pain-like conditions) and side-effect endpoints (respiratory depression and drug self-administration).

RESULTS

BBI-11008 had a 78-fold greater affinity for the delta opioid receptor than the mu receptor, and there was no binding to the kappa opioid receptor. BBI-11008 (3.2-100; 10-32 mg kg-1, i.v.) and morphine (1-10; 1-3.2 mg kg-1, i.v.) produced antinociceptive and anti-allodynic effects in assays of acute thermal nociception and complete Freund's adjuvant (CFA)-induced inflammatory pain, with BBI-11008 being less potent than morphine in both assays. BBI-11008 (1-18 mg kg-1, i.v.) had similar efficacy to gabapentin (10-56 mg kg-1, i.v.) in a spinal nerve ligation (SNL) model of neuropathic pain. In the respiration assay, with increasing %CO2 exposure, BBI-11008 produced an initial increase (32 mg kg-1, s.c.) and then decrease (56 mg kg-1, s.c.) in minute volume (MV) whereas morphine (3.2-32 mg kg-1, s.c.) produced dose-dependent decreases in MV. In the drug self-administration procedure, BBI-11008 did not maintain self-administration at any dose tested.

CONCLUSIONS

These results suggest that the glycopeptide drug candidate possesses broad-spectrum antinociceptive and anti-allodynic activity across a range of pain-like conditions. Relative to morphine or fentanyl, the profile for BBI-11008 in the respiration and drug self-administration assays suggests that BBI-11008 may have less pronounced deleterious side effects. Continued assessment of this compound is warranted.

Effects of chronic physical disease and systemic inflammation on suicide risk in patients with depression: a hospital-based case-control study

BACKGROUND

Few studies have examined the concurrent effects of physical disease and systemic inflammation on suicide risk in patients with depression. The authors investigated the independent contributions of chronic physical disease and systemic inflammation as indexed by C-reactive protein (CRP), on risk of suicide attempt.

METHODS

In this case-control study, 1468 cases of suicide attempters and 14 373 controls, both aged 18-65 years with a diagnosis of depression during 2011-2015, were identified from the hospital-wide database. Regression models were implemented to identify separate effects of physical diseases and systemic inflammation indexed by CRP, on risk of suicide attempt.

RESULTS

Compared with having no physical disease, having one, two, and three or more physical diseases was associated with a 3.6-, 6.4-, and 14.9-fold increase in odds of making a suicide attempt, respectively, after adjusting for age, sex, and race/ethnicity. In a sub-sample of cases and controls with available CRP values, patients with high CRP (>3 mg/L) had 1.9 times the odds of suicide attempt compared with patients with low CRP (<1 mg/L). This association was no longer significant when controlling for the effect of physical disease.

CONCLUSIONS

The presence of physical disease is an important risk factor for suicide attempt among patients with depression. Systemic inflammation is likewise associated with increased risk for suicide attempt, however, this association appears to be accounted for by the presence of physical disease among patients receiving care in a medical center setting. Healthcare providers should consider the risk of suicide attempt in depressed patients burdened with multiple comorbidities.

Increased Behavioral Deficits and Inflammation in a Mouse Model of Co-Morbid Traumatic Brain Injury and Post-Traumatic Stress Disorder

Comorbid post-traumatic stress disorder with traumatic brain injury (TBI) produce more severe affective and cognitive deficits than PTSD or TBI alone. Both PTSD and TBI produce long-lasting neuroinflammation, which may be a key underlying mechanism of the deficits observed in co-morbid TBI/PTSD. We developed a model of co-morbid TBI/PTSD by combining the closed head (CHI) model of TBI with the chronic variable stress (CVS) model of PTSD and examined multiple behavioral and neuroinflammatory outcomes. Male C57/Bl6 mice received sham treatment, CHI, CVS, CHI then CVS (CHI → CVS) or CVS then CHI (CVS → CHI). The CVS → CHI group had deficits in Barnes maze or active place avoidance not seen in the other groups. The CVS → CHI, CVS and CHI → CVS groups displayed increased basal anxiety level, based on performance on elevated plus maze. The CVS → CHI had impaired performance on Barnes Maze, and Active Place Avoidance. These performance deficits were strongly correlated with increased hippocampal Iba-1 level an indication of activated MP/MG. These data suggest that greater cognitive deficits in the CVS → CHI group were due to increased inflammation. The increased deficits and neuroinflammation in the CVS → CHI group suggest that the order by which a subject experiences TBI and PTSD is a major determinant of the outcome of brain injury in co-morbid TBI/PTSD.

Potential application of helminth therapy for resolution of neuroinflammation in neuropsychiatric disorders

Neuropsychiatric disorders (NPDs) are among the major debilitating disorders worldwide with multiple etiological factors. However, in recent years, psychoneuroimmunology uncovered the role of inflammatory condition and autoimmune disorders in the etiopathogenesis of different NPDs. Hence, resolution of inflammation is a new therapeutic target of NPDs. On the other hand, Helminth infections are among the most prevalent infectious diseases in underdeveloped countries, which usually caused chronic infections with minor clinical symptoms. Remarkably, helminths are among the master regulator of inflammatory reactions and epidemiological studies have shown an inverse association between prevalence of autoimmune disorders with these infections. As such, changes of intestinal microbiota are known to be associated with inflammatory conditions in various NPDs. Conversely, helminth colonization alters the intestinal microbiota composition that leads to suppression of intestinal inflammation. In animal models and human studies, helminths or their antigens have shown to be protected against severe autoimmune and allergic disorders, decline the intensity of inflammatory reactions and improved clinical symptoms of the patients. Therefore, "helminthic therapy" have been used for modulation of immune disturbances in different autoimmunity illnesses, such as Multiple Sclerosis (MS) and Inflammatory Bowel Disease (IBD). Here, it is proposed that "helminthic therapy" is able to ameliorate neuroinflammation of NPDs through immunomodulation of inflammatory reactions and alteration of microbiota composition. This review discusses the potential application of "helminthic therapy" for resolution of neuroinflammation in NPDs.

Marriage and Gut (Microbiome) Feelings: Tracing Novel Dyadic Pathways to Accelerated Aging

Within a couple, partners influence each other's mental and physical health. This review focuses on how couples' relationships, the partners' individual and joint vulnerabilities, and their health behaviors influence health through changes in the gut microbiota, metabolism, and immune function. Couples' shared stressors and emotions and their intertwined lifestyles and routines serve to promote common disease risks in part through parallel changes in their gut microbiotas. Marital discord, stress, and depression have strong bidirectional links, fueling one another. Chronic marital stress and depression can elevate the risk for obesity, metabolic syndrome, and cardiovascular disease by altering resting energy expenditure, insulin production, and triglyceride responses after unhealthy meals. During stressful times, health behaviors typically suffer-and sleep disturbances, poor diets, and sedentary behavior all influence these metabolic pathways while also promoting gut dysbiosis. Dysbiosis increases intestinal permeability (gut leakiness), providing a mechanistic pathway from marital distress and depression to heightened inflammation and accelerated aging. Age-related changes in the gut microbiota's composition and gut leakiness foster immunosenescence, as well as the progression of inflamm-aging; these age-related risks may be altered by stress and depression, diet, sleep, exercise habits, and developmental shifts in emotion regulation strategies. Consideration of the strong mutual influences that partners have on each other's mood and health behaviors, as well as the biological pathways that underlie these influences, provides a new way to view marriage's health implications.

Apelin attenuates depressive-like behavior and neuroinflammation in rats co-treated with chronic stress and lipopolysaccharide

Several experimental studies have proved that activation of neuroinflammation pathways may contribute to the development of depression, a neuropsychiatric disorder disease. Our previous studies have shown the antidepressant properties of apelin, but the mechanism was unkown. This study was performed to verify whether the antidepressant effect of apelin was related to its anti-inflammation effect in the central nervous system. To achieve our aim, we selected the co-treatment of chronic stress and LPS to induced an inflammatory process in rats. The effect of this co-treatment was evaluated through the expression of inflammatory markers and glial cell activation. LPS injection co-treated with unpredictable chronic mild stress resulted in the activation of microglial cell and astrocyte, expression of inflammatory markers and depressive behaviors. Treatment with apelin significantly attenuates the deleterious effects in these rats. Our results showed that apelin improved depressive phenotype and decreased the activation of glial cells in stress co-treatment group. The down-regulations of p-NF-κB and p-IKKβ suggested that the effects are possibly mediated by inhibition of the NF-κB-mediated inflammatory response. These findings speculated that intracerebroventricular injection of apelin could be a therapeutic approach for the treatment of depression, and the antidepressant function of apelin may closely associated with its alleviation in neuroinflammation.

Two Distinct Immune Pathways Linking Social Relationships With Health: Inflammatory and Antiviral Processes

OBJECTIVE

Social relationships can both influence and be influenced by immune processes. Past work implicates two distinct pathways along which this interaction may occur: inflammatory processes and antiviral processes. This article reviews how social behavior is modulated by these two immune processes and how such processes may in turn regulate social behavior.

METHODS

This narrative review outlines existing work on social behavior and both inflammatory and antiviral processes. We propose an evolutionary framework that aims to integrate these findings. Specifically, social isolation has evolutionarily increased the likelihood of wounding and therefore increased the need for inflammation, which works to promote healing. Conversely, broader social networks provide protection from physical threats but also lead to increased pathogen exposure, necessitating a more robust antiviral response.

RESULTS

This review highlights that social adversity, such as social exclusion or loneliness, is associated with increased inflammation, whereas social contact is associated with increased antiviral immunity. Furthermore, increased inflammation leads to sensitivity to social stimuli, presumably to avoid hostile conspecifics and approach allies who may provide care while vulnerable. Individuals with inadequate antiviral immunity engage in behaviors that minimize pathogen exposure, such as reduced affiliative behavior.

CONCLUSIONS

This review suggests that adverse social experiences (social isolation, perceived social threat) may induce inflammatory responses while suppressing antiviral immunity, whereas positive experiences of social connection may reduce inflammation and bolster antiviral responses. Although acutely elevated inflammation would be adaptive under conditions where wounding is likely, chronic inflammation related to continued social adversity may have detrimental health consequences.

Role of gut microbiota in the interaction between immunity and psychiatry: a literature review

BACKGROUND

Psychiatric disorders may be correlated with a low-grade systemic inflammation but the origin of this inflammatory response remains unclear and both genetics and environmental factors seems to be concerned. Recent researches observed that gut microbiota seems to have an impact on the brain and immune processes.

METHOD

We review recent literature to a better understanding of how microbiota interacts with brain, immunity and psychiatric disorders. We search on Pubmed, PsycINFO, PsycARTICLES and Sciencedirect articles with the keywords "gastrointestinal microbiota" and "mental disorders" or "psychological stress".

RESULTS

We showed links between gut microbiota and brain-gut axis regulation, immune and endocrine system activity, neurophysiological changes, behavior variations and neuropsychiatric disorders. Communications between brain and gut are bidirectional via neural, endocrine and immune pathway. Microbiota dysbiosis and increase gut permeability with subsequent immune challenges seems to be the source of the chronic mild inflammation associated with neuropsychiatric disorders. Repeated immune or stress events early in life may lead to neurodevelopmental disorders or sickness behavior later in life.

CONCLUSIONS

Psychological stress impact gut microbiota with subsequent immune activation leading to neurodevelopmental disorders or sickness behavior and altering neurophysiology and reactivity to stress or lifestyle.

Inflammation in Tic Disorders and Obsessive-Compulsive Disorder: Are PANS and PANDAS a Path Forward?

This review and commentary is the product of an invited lecture called "Autoimmunity: PANS/PANDAS" presented at the 2018 Neurobiology of Diseases in Children Symposium in Chicago, IL. The talk addressed clinical and scientific questions and recently published data. At this time, among highly experienced and respected clinicians and researchers spanning relevant disciplines, there is substantial controversy regarding a role for inflammation in producing tics and obsessive-compulsive disorder. This commentary summarizes these controversies, discusses reasons for opposing views on best clinical practices, and concludes with suggestions for pathways forward.

Inflammation, Appetite and Food Intake in Older Hospitalized Patients

The effect of inflammation on appetite and food intake has been rarely studied in humans. In this study, we examined the association of C-reactive protein (CRP), as an inflammatory marker, with appetite and food intake among older hospitalized patients. A total of 200 older individuals, who were consecutively admitted to a geriatric acute care ward, participated in this prospective observational study. Appetite was evaluated using the Edmonton Symptom Assessment System (ESAS) and the Simplified Nutritional Appetite Questionnaire (SNAQ), respectively. Food intake was measured according to plate diagram method and participants were categorized as having food intake <75% and ≥75% of meals served. Nutritional status was evaluated using the Mini Nutritional Assessment Short Form (MNA-SF). In addition, serum CRP was analyzed and the levels >3.0 (mg/dL) were considered as moderate to severe inflammation. Of total population with mean age 81.4 ± 6.6 years (62.5% females), 51 (25.5%) had no inflammation and 88 (44.0%) and 61 (30.5%) had mild and moderate to severe inflammation, respectively. According to MNA-SF, 9.0% and 60.0% had normal nutritional status or a risk of malnutrition, respectively, whereas 31.0% were malnourished. Based on the SNAQ-appetite-question, 32.5% of the patients demonstrated poor and very poor appetite whereas 23.5% reported severe loss of appetite according to ESAS. Ninety-five (48.0%) of the participants had food intake <75% of the meals offered. Significant associations between SNAQ-appetite (p = 0.003) and ESAS-appetite (p = 0.013) scores and CRP levels were observed. In addition, significant differences were observed in CRP levels between intake ≥75% and <75% of meals served (p < 0.001). Furthermore, there were significant associations between appetite and nutritional status whereas malnourished older patients demonstrated a decreased appetite compared to those with normal nutritional status (p = 0.011). In a regression analysis, inflammation was the major independent risk factor for patients' appetite (p = 0.003) and food intake (p = 0.011) whereas other variables such as infection (p = 0.960), chronic inflammatory diseases (p = 0.371), age (p = 0.679) and gender (p = 0.447) do not show any impact on appetite. Our findings confirm that poor appetite and low food intake are associated with inflammation in older hospitalized patients, suggesting that inflammation may contribute an important aspect to the development of malnutrition in these patients.

A new cationic palladium(II) dithiocarbamate exhibits anti-inflammatory, analgesic, and antipyretic activities through inhibition of inflammatory mediators in in vivo models

Inflammation is being a protective mechanism of the body towards the injury. However, chronic and progressive inflammation may lead to some chronic diseases. Due to the serious unwanted effects associated with available drugs, new and safe anti-inflammatory agents are still required. Therefore, the present study was designed to investigate the anti-inflammatory, analgesics, and antipyretic properties of a new compound (4-benzylpiperidine-1-carbodithioato-κ2S,S')(1,4-bis-(diphenylphosphino)butane)palladium(II)chloride monohydrate (compound-1) in albino mice models. Compound-1 was characterized by elemental analysis, FT-IR, and multinuclear NMR spectroscopy. Initially, compound-1 was evaluated for cytotoxicity, anti-inflammatory, and analgesic activities by performing MTT assay, carrageenan-, histamine-, serotonin-, and CFA-induced paw edema, mechanical hyperalgesia, thermal hyperalgesia, and mechanical allodynia (0.1, 1, and 10 mg/kg, b.w). Antipyretic activity was evaluated in brewer's yeast-induced model. The pro-inflammatory cytokines were measured by using commercially available ELISA kits. Additionally, nitrite production, antioxidant enzymes, H&E staining, muscle activity and motor coordination, and kidney and liver function tests were also determined. The results demonstrated that compound-1 significantly inhibited inflammation, pain, and febrile responses in all models at a dose of 10 mg/kg without effecting viability of cells in vitro at concentrations up to 100 μM. Similarly, the data clearly demonstrated significant reduction in the pro-inflammatory cytokines and nitrite production while enhancing antioxidant enzymes. Furthermore, pretreatment with compound-1 did not produce any prominent side effect on kidney, liver, stomach, and muscles. These findings suggest that compound-1 has potent anti-inflammatory-, pain-, and pyrexia-relieving properties. Hence, compound-1 might be a potential candidate for the therapeutic management of chronic inflammation and pain.

Mindfulness training and systemic low-grade inflammation in stressed community adults: Evidence from two randomized controlled trials

Mindfulness interventions have garnered significant attention as a complementary health treatment for many physical and psychological conditions. While some research has shown that mindfulness training can decrease psychological and physiological stress responses, it remains unclear whether mindfulness training impacts inflammation—a predictor of poor health outcomes. In addition, little research has examined the active components of mindfulness that may drive health-related improvements. Here, we provide data from two 3-arm randomized controlled trials that examined the effect of mindfulness training on inflammation in stressed community adults. Specifically, we examined whether training individuals to have an accepting attitude towards present moment experiences is a key emotion regulation skill that can lead to decreases in inflammation. Both studies randomly assigned participants to one of three conditions: mindfulness training that taught both attention monitoring and acceptance skills (Monitor+Accept); mindfulness training teaching monitoring without the acceptance component (Monitor Only); or a control condition. Study 1 employed a novel 2-week smartphone-based intervention and Study 2 employed a standard 8-week Mindfulness-Based Stress Reduction (MBSR) intervention. We hypothesized that Monitor+Accept training would lead to reductions in the inflammatory biomarker C-Reactive Protein (CRP) compared to Monitor Only training and control groups. Contrary to this hypothesis, we found that Monitor+Accept mindfulness training did not lead to reductions in CRP. Exploratory analyses combining study subsamples, however, suggest that both mindfulness interventions may reduce CRP in populations at risk for systemic inflammation—midlife-to-older adults and individuals with high BMI. Overall, the present studies contribute significantly to the question of whether mindfulness interventions can reduce systemic markers of low-grade inflammation.

The associations between self-reported depression, self-reported chronic inflammatory conditions and cognitive abilities in UK Biobank

Background

Depression and chronic inflammatory medical conditions have been linked to impaired cognitive ability. However despite frequent comorbidity, their combined association with cognitive ability has rarely been examined.

Methods

This study examined associations between self-reported depression and chronic inflammatory diseases and their interaction with cognitive performance in 456,748 participants of the UK Biobank, adjusting for sociodemographic and lifestyle factors. Numbers with available data ranged from 94,899 to 453,208 depending on the cognitive test.

Results

Self-reported depression was associated with poorer performance compared to controls in several cognitive tests (fully adjusted models, reaction time: B = 6.08, 95% CI = 5.09, 7.07; pairs matching: incidence rate ratio = 1.02, 95% CI = 1.02, 1.03; Trail Making Test B: B = 1.37, 95% CI = 0.88, 1.87; Digit Symbol Substitution Test (DSST): B = −0.35, 95% CI = −0.44, −0.27). Self-reported chronic inflammatory conditions were associated with slower reaction time (B = 3.79, 95% CI = 2.81, 4.78) and lower DSST scores (B = −0.21, 95% CI = −0.30, −0.13). No interaction effects were observed.

Discussion

In this large, population-based study we provide evidence of lower cognitive performance in both depression and a comprehensive category of chronic inflammatory conditions. Results are consistent with additive effects of both types of disorder on cognitive ability. Clinicians should be aware of such effects, particularly as cognitive impairment is linked to poorer disease outcomes and quality of life.

In vivo direct relation of tau pathology with neuroinflammation in early Alzheimer's disease

OBJECTIVE

Neuronal damage and neuroinflammation are important events occurring in the brain of Alzheimer's disease (AD). The purpose of this study was to clarify in vivo mutual relationships among abnormal tau deposition, neuroinflammation and cognitive impairment in patients with early AD using positron emission tomography (PET) with [¹¹C]PBB3 and [¹¹C]DPA713.

METHODS

Twenty patients with early AD and 20 age-matched normal control (NC) subjects underwent a series of PET measurements with [¹¹C]PBB3 for tau aggregation and [¹¹C]DPA713 for microglial activation (neuroinflammation). Inter- and intrasubject comparisons were performed regarding the levels of [¹¹C]PBB3 binding potential (BP_ND) and [¹¹C]DPA713 BP_ND in the light of cognitive functions using statistical parametric mapping (SPM) and regions of interest (ROIs) method.

RESULTS

The [¹¹C]PBB3 BP_ND was greater in the temporo-parietal regions of AD patents than NC subjects, and a similar increasing pattern of [¹¹C]DPA713 BP_ND was observed in the same patients. Correlation analyses within the AD group showed a positive direct correlation between [¹¹C]PBB3 BP_ND and [¹¹C]DPA713 BP_ND in the parahippocampus. Pass analysis revealed that cognitive impairment was more likely linked to the level of the parahippocampal [¹¹C]PBB3 BP_ND than that of [¹¹C]DPA713 BP_ND.

CONCLUSIONS

The pattern of abnormal tau deposition was very similar to that of neuroinflammation in patients with early-stage AD. Specifically, the direct positive correlation of tau pathology with neuroinflammation in the parahippocampus suggests that neuronal damage in this region is closely associated with microglial activation. Consistently, tau aggregation in this region matters more than neuroinflammation regarding the cognitive deterioration in AD.

Independent and joint association of obesity and metabolic syndrome with depression and inflammation

OBJECTIVE

To investigate the separate and combined associations of obesity and metabolic syndrome (MetS) with depression and the role of inflammation.

METHOD

Depression was assessed with the Patient Health Questionnaire-9 (PHQ-9) and was defined with a cutpoint of ≥10. Obesity was defined as body mass index (BMI) ≥30 kg/m2 from measured height and weight. MetS was defined based on the American Heart Association consensus definition. Participants were divided into four groups: healthy normal weight (MHN), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUN), and metabolic unhealthy obese (MUO). C-Reactive protein was assessed in a subsample.

RESULTS

A total of 18,025 subjects were included in the analysis. Participants with MUO had the highest prevalence of depression compared with the MHN group (14.8% vs. 6.8, p < .001). While both obesity and MetS were independently associated with depression, there was a significant interaction between the two (p < .001), indicating that the associations of obesity and MetS with depression were synergistic. After adjusting for baseline characteristics, compared with the MHN group, the MUO group had the highest odds of depression (odds ratio [OR] = 2.30, 95% CI [2.03, 2.61]), followed by MHO group (OR = 1.51, 95% CI [1.30, 1.74]) and the MUN group (OR = 1.39, 95% CI [1.18, 1.64]). The MUO group also showed the highest level of C-reactive protein, and the latter partially mediated the effect between MUO and depressive symptoms (20.5% of the total effect).

CONCLUSION

Both obesity and MetS are associated with depression independent of each other, but when present together, these conditions have a synergistic association with depression. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Perceived relationship support moderates the association of contextual stress with inflammation among African Americans

We followed 402 African American young adults from ages 24 to 29, a period of emerging committed relationships, to examine the association of contextual stress (CS), for example, experiences of financial strain, victimization, and racial discrimination, with inflammation, and to test predictions that greater perceived relationship warmth and support (PRWS) at age 29 would moderate the association between earlier CS and inflammation, using a multiplex assessment of cytokines to construct an index of the ratio between predominantly proinflammatory cytokines versus predominantly anti-inflammatory cytokines. CS experienced at age 24 was associated with greater inflammation at age 29 in the full sample (b = .112, p = .004). PRWS at age 29 moderated the association of earlier CS with inflammation (b = -.114, p = .011), but there was no significant main effect of PRWS (b = -.053, p = .265). Finally, using an internal moderator approach, we compared the association of CS with inflammation among those not in a committed relationship to those in more or less supportive relationships, showing a significant and stronger association of CS with inflammation for those with low PRWS (-1 SD; b = .182, p < .001), a weaker and nonsignificant association of CS with inflammation among those with higher PRWS (+1 SD; b = -.002, p = .975), and an intermediate and nonsignificant association of CS with inflammation among those with no committed romantic relationship (b = .077, p = .227). Results were robust to number of cytokines included in the inflammation index. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Amyloid-β plaque formation and reactive gliosis are required for induction of cognitive deficits in App knock-in mouse models of Alzheimer's disease

BACKGROUND

Knock-in (KI) mouse models of Alzheimer's disease (AD) that endogenously overproduce Aβ without non-physiological overexpression of amyloid precursor protein (APP) provide important insights into the pathogenic mechanisms of AD. Previously, we reported that AppNL-G-F mice, which harbor three familial AD mutations (Swedish, Beyreuther/Iberian, and Arctic) exhibited emotional alterations before the onset of definitive cognitive deficits. To determine whether these mice exhibit deficits in learning and memory at more advanced ages, we compared the Morris water maze performance of AppNL-G-F and AppNL mice, which harbor only the Swedish mutation, with that of wild-type (WT) C57BL/6J mice at the age of 24 months. To correlate cognitive deficits and neuroinflammation, we also examined Aβ plaque formation and reactive gliosis in these mice.

RESULTS

In the Morris water maze, a spatial task, 24-month-old AppNL-G-F/NL-G-F mice exhibited significantly poorer spatial learning than WT mice during the hidden training sessions, but similarly to WT mice during the visible training sessions. Not surprisingly, AppNL-G-F/NL-G-F mice also exhibited spatial memory deficits both 1 and 7 days after the last training session. By contrast, 24-month-old AppNL/NL mice had intact spatial learning and memory relative to WT mice. Immunohistochemical analyses revealed that 24-month-old AppNL-G-F/NL-G-F mice developed massive Aβ plaques and reactive gliosis (microgliosis and astrocytosis) throughout the brain, including the cortex and hippocampus. By contrast, we observed no detectable brain pathology in AppNL/NL mice despite overproduction of human Aβ40 and Aβ42 in their brains.

CONCLUSIONS

Aβ plaque formation, followed by sustained neuroinflammation, is necessary for the induction of definitive cognitive deficits in App-KI mouse models of AD. Our data also indicate that introduction of the Swedish mutation alone in endogenous APP is not sufficient to produce either AD-related brain pathology or cognitive deficits in mice.

Sarcopenia and Its Implications for Metabolic Health

Sarcopenia not only affects the ability to lead an active lifestyle but also contributes to increased obesity, reduced quality of life, osteoporosis, and metabolic health, in part due to reduced locomotion economy and ease. On the other hand, increased obesity, decreased quality of life, and reduced metabolic health also contribute to sarcopenia. The purpose of this mini-review is to discuss the implications sarcopenia has for the development of obesity and comorbidities that occur with aging.

Neighborhood social cohesion is associated with lower levels of interleukin-6 in African American women

INTRODUCTION

Social cohesion is a positive neighborhood characteristic defined by feelings of connectedness and solidarity within a community. Studies have found significant associations between social cohesion and cardiovascular disease (CVD) risk factors and outcomes. Inflammation is one potential physiological pathway linking social cohesion to CVD development, but few studies have evaluated the relationship between social cohesion and inflammatory biomarkers. Prior research has also established that race and gender can modify the effects of neighborhood features, including social cohesion, on CVD risk factors and outcomes. This study aimed to examine the association between social cohesion and the inflammatory biomarkers interleukin-6 (IL-6) and C-reactive protein (CRP) in a cohort of African American and White women and men.

MATERIALS AND METHODS

Data from the Morehouse and Emory Team Up to Eliminate Health Disparities (META-Health) Study were used to assess the association between social cohesion and inflammation among African American (n = 203) and White (n = 176) adults from the Atlanta metropolitan area. Social cohesion was measured using the social cohesion subscale from the Neighborhood Health Questionnaire. Inflammatory biomarkers were measured from plasma frozen at -70 °C. Multivariable linear regression analyses were conducted, controlling for demographic, clinical, behavioral, and psychosocial factors sequentially. Interaction by race and gender was also examined.

RESULTS

In models adjusted for age, race, gender, and education, social cohesion was significantly associated with lower levels of IL-6 (β = -0.06, p = 0.03). There was a significant race × social cohesion interaction (p = 0.04), and a marginally significant gender × race × social cohesion interaction (p = 0.09). In race-stratified models controlling for age, gender, and education, social cohesion was associated with lower IL-6 levels in African Americans (β = -0.11, p = 0.01), but not Whites (β = 0.01, p = 0.91). In fully adjusted race- and gender-stratified models, social cohesion was associated with lower levels of IL-6 in African American women only (β = -0.15, p = 0.003). CRP was not associated with social cohesion in fully adjusted models.

CONCLUSION

The association between social cohesion and lower levels of IL-6 is modified by gender and race, with the strongest association emerging for African American women. Although the pathways through which social cohesion impacts inflammation remain unclear, it is possible that for African American women social cohesion manifests through neighborhood networks.

Old Friends, immunoregulation, and stress resilience

There is a considerable body of evidence indicating that chronic adverse experience, especially chronic psychosocial stress/trauma, represents a major risk factor for the development of many somatic and affective disorders, including inflammatory bowel disease (IBD) and posttraumatic stress disorder (PTSD). However, the mechanisms underlying the development of chronic stress-associated disorders are still in large part unknown, and current treatment and prevention strategies lack efficacy and reliability. A greater understanding of mechanisms involved in the development and persistence of chronic stress-induced disorders may lead to novel approaches to prevention and treatment of these disorders. In this review, we provide evidence indicating that increases in immune (re-)activity and inflammation, potentially promoted by a reduced exposure to immunoregulatory microorganisms ("Old Friends") in today's modern society, may be causal factors in mediating the vulnerability to development and persistence of stress-related pathologies. Moreover, we discuss strategies to increase immunoregulatory processes and attenuate inflammation, as for instance contact with immunoregulatory Old Friends, which appears to be a promising strategy to promote stress resilience and to prevent/treat chronic stress-related disorders.

Fto Deficiency Reduces Anxiety- and Depression-Like Behaviors in Mice via Alterations in Gut Microbiota

Depression and obesity have high concurrence within individuals, which may be explained by sharing the same risk factors, including disruption of the intestinal microbiota. However, evidence that delineated the causal connections is extremely scarce. Methods: Mice lacking fat mass- and obesity-associated gene (Fto) were generated. Fto-deficient and wild-type control mice were subjected to novel conditions with or without chronic unpredictable mild stress (CUMS) for 6 weeks. Some mice were treated with antibiotics via their drinking water for 6 weeks in order to deplete their microbiota. Behavioral tests were performed to evaluate anxiety- and depression-like behaviors. 16S rRNA amplicon and metagenomic sequencing were employed to analyse fecal microbiota. Plasma levels of inflammatory cytokines and lipopolysaccharides (LPS) were also compared. Results: Deletion of Fto led to lower body weight and decreased anxiety- and depression-like behaviors, Fto+/- mice were also less susceptible to stress stimulation, highlighting the essential role of Fto in pathogenesis of depression. With regard to gut microbiota, Fto deficiency mice harbored specific bacterial signature of suppressing inflammation, characterized with higher abundance of Lactobacillus, lower Porphyromonadaceae and Helicobacter. Critically, behavioral alterations of Fto+/- mice are mediated by shift in gut microbiota, as such changes can be partially attenuated using antibiotics. Exposure to CUMS increased serum IL-6 level while Fto deficiency reduced its level, which may be explained by a lower LPS concentration. Conclusion: Together, our findings uncover the roles of Fto on depression and provide insights into microbiota-related biological mechanisms underlying the association between obesity and depression.

Purple sweet potato color improves hippocampal insulin resistance via down-regulating SOCS3 and galectin-3 in high-fat diet mice

Hippocampal insulin resistance is the key factor in cognitive deficits. The obesity induces chronic inflammation and the inflammation molecules suppressors of cytokine signaling3 (SOCS3) and galectin-3 directly impair the insulin signaling. The anti-inflammation properties of purple sweet potato color (PSPC) prompted us to investigate the effect of PSPC on cognitive impairment associated with obesity. 60 C57BL/6 mice were randomly divided into four groups: normal, high fat diets (HFD), HFD+PSPC and PSPC. The mice were fed with the HFD or normal diet for 32 weeks. The PSPC (500 mg/kg/day) was administered via oral gavage from 21 to 32 weeks. The results showed the PSPC rectified the abnormal metabolism indexes induced by HFD, including ameliorated obesity, decreased the concentration of fasting blood glucose and improved the glucose tolerance. The Morris water maze test showed the PSPC alleviated the cognitive impairment in HFD mice. The PSPC decreased the expression of Iba1, tumor necrosis factor-α, interleukin-1β, SOCS3 and galectin-3 in hippocampus of HFD mice. The insulin signaling molecules including the p-IRS1 (Tyr608), PI3K p110α and p-AKT (Ser473) were detected and the PSPC treatment improved the insulin resistance in hippocampus of HFD mice. Furthermore, the PSPC increased Bcl-2, diminished the Bak and the cleaved-caspase3 in HFD mice hippocampus. These findings indicated that PSPC could be a potential treatment to improve the cognitive impairment associated with obesity.

Solid peripheral tumor leads to systemic inflammation, astrocyte activation and signs of behavioral despair in mice

Prevalence of depression is higher in patients with cancer than in the general population. Sustained systemic inflammation has been associated with depressive behavior and it has been reported that depressed patients commonly display alterations in their immune system. We previously showed that cancer in mice induces a systemic environment that promotes neutrophil activation and leukocytosis. We thus hypothesized that the peripheral systemic response to a solid tumor leads to endothelial activation, which may promote inflammatory changes in the brain with behavioral consequences. Using the Lewis lung carcinoma (LLC) model, we show that tumor growth induces a progressive increase in peripheral inflammation as observed by elevated interleukin-6 (IL-6). In behavioral studies, tumor-bearing mice showed no sign of motor, coordination or short term working memory deficits as assessed by rotarod, balance-beam, and novel object recognition tests. However, there was an impairment in the grip strength test and interestingly, an anxious and despair-like phenotype in the elevated plus-maze, and tail suspension tests, respectively. Immunostaining of perfused brains revealed fibrin accumulation in the vasculature with some leakage into the parenchyma, a process known to activate endothelial cells. Taken together, our results suggest that the inflamed and prothrombotic systemic environment created by the growth of a peripherally-located solid tumor induces endothelial activation, accumulation of fibrin in the brain and astrocyte activation, perhaps leading to depressive-like behavior.

The role of inflammation in core features of depression: Insights from paradigms using exogenously-induced inflammation

A wealth of evidence has implicated inflammation in the development of depression. Yet, the heterogeneous nature of depression has impeded efforts to understand, prevent, and treat the disease. The purpose of this integrative review is to summarize the connections between inflammation and established core features of depression that exhibit more homogeneity than the syndrome itself: exaggerated reactivity to negative information, altered reward processing, decreased cognitive control, and somatic syndrome. For each core feature, we first provide a brief overview of its relevance to depression and neurobiological underpinnings, and then review evidence investigating a potential role of inflammation. We focus primarily on findings from experimental paradigms of exogenously-induced inflammation. We conclude that inflammation likely plays a role in exaggerated reactivity to negative information, altered reward reactivity, and somatic symptoms. There is less evidence supporting an effect of inflammation on cognitive control as assessed by standard neuropsychological measures. Finally, we discuss implications for future research and recommendationsfor how to test the role of inflammation in the pathogenesis of heterogeneous psychiatric disorders.

Effects of psychological interventions on systemic levels of inflammatory biomarkers in humans: A systematic review and meta-analysis

The purpose of the present investigation was to systematically review randomized controlled trials examining the effects of psychological interventions on inflammatory biomarkers in adult populations and to quantitatively analyze those effects by meta-analysis. Two researchers independently searched key electronic databases, selected eligible publications, extracted data, and evaluated methodological quality. Nineteen randomized controlled trials examining a total of 1510 participants were included. The overall combined effect size from pre to post psychological intervention on pro-inflammatory biomarker levels was statistically significant, showing an attenuating effect, although of a small magnitude (s' g = 0.15, p = .008, CI [0.04-0.26]). However, this effect was not maintained into the follow-up period (g < -0.01, p = .964, CI [-0.19-0.18]). Looking at the individual biomarkers assessed across studies, only C-reactive protein (CRP) was found to significantly decrease following psychological intervention. A number of moderation analyses were conducted, none of which reached statistical significance. However, the numerically largest - and significant - within-group effect size was obtained for the group of studies that had preselected participants based on elevated psychological distress (g = 0.29, p = .047). In conclusion, psychological interventions appear efficacious in reducing pro-inflammatory biomarker levels. Future studies are recommended to carefully select individuals based on inflammatory (e.g., the presence of low-grade inflammation) and/or psychological (e.g., psychological distress) criteria.

Social stress during adolescence activates long-term microglia inflammation insult in reward processing nuclei

The experience of social stress during adolescence is associated with higher vulnerability to drug use. Increases in the acquisition of cocaine self-administration, in the escalation of cocaine-seeking behavior, and in the conditioned rewarding effects of cocaine have been observed in rodents exposed to repeated social defeat (RSD). In addition, prolonged or severe stress induces a proinflammatory state with microglial activation and increased cytokine production. The aim of the present work was to describe the long-term effects induced by RSD during adolescence on the neuroinflammatory response and synaptic structure by evaluating different glial and neuronal markers. In addition to an increase in the conditioned rewarding effects of cocaine, our results showed that RSD in adolescence produced inflammatory reactivity in microglia that is prolonged into adulthood, affecting astrocytes and neurons of two reward-processing areas of the brain (the prelimbic cortex, and the nucleus accumbens core). Considered as a whole these results suggest that social stress experience modulates vulnerability to suffer a loss of glia-supporting functions and neuronal functional synaptic density due to drug consumption in later life.

I do not want to suppress the natural process of inflammation: new insights on factors associated with non-adherence in rheumatoid arthritis

BACKGROUND

It is estimated that 50-70% of patients with rheumatoid arthritis (RA) are non-adherent to their recommended treatment. Non-adherent patients have a higher risk of not reaching an optimal clinical outcome. We explored factors associated with nonadherence from the patient's perspective.

METHODS

Four hundred and fifty-nine RA patients (346 (75.4%) females; mean age 63.0 ± 14.8 years) who failed to attend follow-up visits in two rheumatology centres were eligible to participate in a qualitative interview study. We used this strategy to identify patients who were potentially non-adherent to medicines and/or non-pharmacological interventions. By means of meaning condensation analysis, we identified new and some already well known insights to factors associated with non-adherence. We used the capability, opportunity, and motivation model of behaviour (COM-B) model as a frame of reference to classify the factors.

RESULTS

Forty-three of 131 patients (32.8%) who agreed to participate in the qualitative interviews were found to be non-adherent. New insights on factors associated with non-adherence included strong opinions of patients, such as pain being considered as an indicator of hard work and something to be proud of, or inflammation being a natural process that should not be suppressed; feeling not to be in expert's hands when being treated by a physician/health professional; the experience of excessive self-control over the treatment; and rheumatologists addressing only drugs and omitting non-pharmacological aspects. The COM-B model comprehensively covered the range of our findings.

CONCLUSIONS

The new insights on factors associated with non-adherence allow a better understanding of this phenomenon and can substantially enhance patient care by helping to develop targeted interventions.

Food intake and high-sensitivity C-reactive protein levels in adolescents

BACKGROUND AND AIMS

Diet comprises factors with anti and pro-inflammatory potential that can contribute to modulate obesity-induced inflammation. We aimed to assess the association between food intake and high-sensitivity C-reactive protein (hsCRP) levels in adolescents.

METHODS AND RESULTS

A cross-sectional analysis of 991 adolescents aged 13 years old was conducted as part of the EPITeen cohort, Porto, Portugal. Food intake was assessed by a food frequency questionnaire and thirteen food groups were defined. Anthropometric assessment was performed and serum hsCRP was measured in a fasting blood sample. hsCRP concentrations above the 75th percentile were considered high. Logistic regression was fitted to estimate the association between the intake frequency of the food groups and hsCRP, stratified by BMI and adjusted for sex, parental education and total energy intake. Median (25-75th percentiles) hsCRP concentrations increased with increasing values of BMI [normal weight: 0.20 (0.10-0.50); overweight: 0.40 (0.20-0.80); obese: 1.10 (0.40-2.15) mg/l, p < 0.001]. After adjustment for sex, parental education and total energy intake, no statistically significant associations were found amongst normal weight and overweight participants. However, among obese individuals, having as reference the first frequency category (<1 per day), a higher frequency of vegetables/legumes intake showed a decreased odds of high hsCRP levels (OR: 0.10, 95%CI 0.03-0.38, 1-3 per day; and OR: 0.14, 95%CI 0.04-0.52, >3 per day).

CONCLUSION

Among participants with obesity-induced higher hsCRP levels, a higher frequency of vegetable/legume intake was inversely related to hsCRP.

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.