Glucocorticoid mediated regulation of inflammation in human monocytes is associated with depressive mood and obesity

Inflammatory mediation of the relationship between early adversity and major depressive disorder: A systematic review

Early adverse experience is related to psychiatric illness that occurs decades later. The mechanisms underlying this phenomenon have not been fully identified. There is a translational and clinical literature linking early adversity with Major Depressive Disorder (MDD) and inflammation. We reviewed articles that examine whether inflammation mediates this relationship.

METHODS

Literature review of PUB MED, CINAHL and APA Psycinfo articles that explicitly examine inflammation as a mediator between early adversity and depression using ((((((((((adversity) OR (trauma)) OR (maltreatment)) OR (child abuse)) AND (inflammation)) OR (inflammatory cytokines)) OR (crp)) OR (il-6)) OR (tnf)) AND (mediates)) AND (depression))))))))) as key words.

RESULTS

2842 articles were initially identified. 1338 non-human studies were excluded and 512 more were filtered out as reviews. The remaining 992 titles and, when necessary, abstracts and manuscripts were reviewed and 956 were removed as being of other non-related phenomena. Four additional studies were added by hand searching the references of remaining studies. Out of these 40, 15 explicitly examined inflammation as a mediator of the relationship between early adversity and later depression. Approximately half (8/15) showed evidence that inflammation mediated the relationship between early adversity and depression. Sensitivity analyses showed that studies taking place in clinical populations, in youth and those that used the Adverse Childhood Events Scale to measure adversity, and IL-6 and TNF-α (as opposed to CRP) to measure inflammation were most likely to show mediation.

CONCLUSIONS

There is evidence to support the model of inflammation mediating the relationship between early adversity and depression. Certain measures in clinical populations appear more likely to support this model. Further study with more standardized, robust methods will help to answer this question more definitively and may elucidate a subtype of depression related to early adversity by alterations in immune function.

Association of anxiety and depressive symptoms with C-reactive protein in diverse Latinos: Results from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

BACKGROUND

High sensitivity C-reactive protein (hsCRP) is a marker of systemic inflammation that has been associated with persistent depressive symptoms. Depression and anxiety are frequently associated with a chronic inflammatory state, yet the nature of this relationship has not been rigorously examined in diverse Hispanic/Latino populations. We aimed to study the association of anxiety and depressive symptoms as well as comorbid presentations, with circulating high sensitivity C-reactive protein (hsCRP) levels in a large Latino cohort of diverse heritages. We hypothesized a significant positive associations of both anxiety and depressive symptoms and hsCRP levels and potential variations among the heritage groups.

METHODS

Depressive symptoms and anxiety were measured by the Center for Epidemiological Studies Depression Scale (CES-D) and State-Trait Anxiety Inventory (STAI), respectively. Serum hsCRP (hsCRP) levels of 15,448 participants (age 18 to 75 years; 52.3% women) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) were measured and categorized based on the established cardiovascular disease (CVD) risk reference values (< 1mg/L, low; 1-<3 mg/L, intermediate; ≥ 3mg/L, high).

RESULTS

Mean CES-D, STAI scores, and hsCRP levels were 7.0 (SD = 5.9), 17.0 (SD = 5.7), and 3.84 (SD = 7.85), respectively. Generalized linear modeling, adjusted for sociodemographic characteristics revealed significant associations between depression (exp(β) = 1.12; p<0.01) and anxiety symptoms (exp(β) = 1.10; p<0.05) with continuous hsCRP levels. For categorical values of hsCRP, one SD increase in CES-D and STAI scores was associated with a 10% and 8% increase in the RRRs of high vs. low hsCRP, respectively. However, these relationships between CES-D or STAI and hsCRP were no longer statistically significant after adjustment for CVD risk factors and medications.

CONCLUSION

We found modest associations between anxiety and depressive symptoms and systemic inflammation measured by hsCRP among diverse Hispanics/Latinos that did not appreciably differ between heritage groups.

Impact of duration of critical illness and level of systemic glucocorticoid availability on tissue-specific glucocorticoid receptor expression and actions: A prospective, observational, cross-sectional human and two translational mouse studies

Background

Reduced glucocorticoid-receptor (GR) expression in blood suggested that critically ill patients become glucocorticoid-resistant necessitating stress-doses of glucocorticoids. We hypothesised that critical illness evokes a tissue-specific, time-dependent expression of regulators of GR-action which adaptively guides glucocorticoid action to sites of need.

Methods

We performed a prospective, observational, cross-sectional human study and two translational mouse studies. In freshly-isolated neutrophils and monocytes and in skeletal muscle and subcutaneous adipose tissue of 137 critically ill patients and 20 healthy controls and in skeletal muscle and adipose tissue as well as in vital tissues (heart, lung, diaphragm, liver, kidney) of 88 septic and 26 healthy mice, we quantified gene expression of cortisone-reductase 11β-HSD1, glucocorticoid-receptor-isoforms GRα and GRβ, GRα-sensitivity-regulating-co-chaperone FKBP51, and GR-action-marker GILZ. Expression profiles were compared in relation to illness-duration and systemic-glucocorticoid-availability.

Findings

In patients’ neutrophils, GRα and GILZ were substantially suppressed (p≤0·05) throughout intensive care unit (ICU)-stay, while in monocytes low/normal GRα coincided with increased GILZ (p≤0·05). FKBP51 was increased transiently (neutrophils) or always (monocytes,p≤0·05). In patients’ muscle, 11β-HSD1 and GRα were low-normal (p≤0·05) and substantially suppressed in adipose tissue (p≤0·05); FKBP51 and GILZ were increased in skeletal muscle (p≤0·05) but normal in adipose tissue. GRβ was undetectable. Increasing systemic glucocorticoid availability in patients independently associated with further suppressed muscle 11β-HSD1 and GRα, further increased FKBP51 and unaltered GILZ (p≤0·05). In septic mouse heart and lung, 11β-HSD1, FKBP51 and GILZ were always high (p≤0·01). In heart, GRα was suppressed (p≤0·05), while normal or high in lung (all p≤0·05). In diaphragm, 11β-HSD1 was high/normal, GRα low/normal and FKBP51 and GILZ high (p≤0·01). In kidney, 11β-HSD1 transiently increased but decreased thereafter, GRα was normal and FKBP51 and GILZ high (p≤0·01). In liver, 11β-HSD1 was suppressed (p≤0·01), GRα normal and FKBP51 high (p≤0·01) whereas GILZ was transiently decreased but elevated thereafter (p≤0·05). Only in lung and diaphragm, treatment with hydrocortisone further increased GILZ.

Interpretation

Tissue-specific, time-independent adaptations to critical illness guided GR-action predominantly to vital tissues such as lung, while (partially) protecting against collateral harm in other cells and tissues, such as neutrophils. These findings argue against maladaptive generalised glucocorticoid-resistance necessitating glucocorticoid-treatment.

Funding

Research-Foundation-Flanders, Methusalem-Program-Flemish-Government, European-Research-Council, European-Respiratory-Society.

Salivary bacterial signatures in depression-obesity comorbidity are associated with neurotransmitters and neuroactive dipeptides

BACKGROUND

Depression and obesity are highly prevalent, often co-occurring conditions marked by inflammation. Microbiome perturbations are implicated in obesity-inflammation-depression interrelationships, but how the microbiome mechanistically contributes to pathology remains unclear. Metabolomic investigations into microbial neuroactive metabolites may offer mechanistic insights into host-microbe interactions. Using 16S sequencing and untargeted mass spectrometry of saliva, and blood monocyte inflammation regulation assays, we identified key microbes, metabolites and host inflammation in association with depressive symptomatology, obesity, and depressive symptomatology-obesity comorbidity.

RESULTS

Gram-negative bacteria with inflammation potential were enriched relative to Gram-positive bacteria in comorbid obesity-depression, supporting the inflammation-oral microbiome link in obesity-depression interrelationships. Oral microbiome was more highly predictive of depressive symptomatology-obesity co-occurrences than of obesity or depressive symptomatology independently, suggesting specific microbial signatures associated with obesity-depression co-occurrences. Mass spectrometry analysis revealed significant changes in levels of signaling molecules of microbiota, microbial or dietary derived signaling peptides and aromatic amino acids among depressive symptomatology, obesity and comorbid obesity-depression. Furthermore, integration of the microbiome and metabolomics data revealed that key oral microbes, many previously shown to have neuroactive potential, co-occurred with potential neuropeptides and biosynthetic precursors of the neurotransmitters dopamine, epinephrine and serotonin.

CONCLUSIONS

Together, our findings offer novel insights into oral microbial-brain connection and potential neuroactive metabolites involved.

Eight Weeks of Lifestyle Change: What are the Effects of the Healthy Lifestyle Community Programme (Cohort 1) on Cortisol Awakening Response (CAR) and Perceived Stress?

Background: Stress and cortisol dysregulation are linked to NCDs. Moreover, stress favours unhealthy lifestyle patterns, which increase the risk for NCDs. The role of the Cortisol Awakening Response (CAR) and the effect of lifestyle interventions on the same remain unclear. Methods: The impact of the intensive 8-week phase of the Healthy Lifestyle Community Programme (HLCP, cohort 1) on parameters of the CAR, ie cortisol values 0 (sample [S]1), 30), 45 and 60 minutes post-awakening, average peak, S1-peak delta and area under the increase curve (AUCI), and perceived stress levels (PSL) was evaluated in a non-randomized, controlled trial. Covariates of the CAR (eg sleep measures) and irregularities in sampling were assessed. The intervention focussed on stress management, a healthy diet, regular exercise, and social support. Participants were recruited from the general population. Multiple linear regression analyses were conducted. Results: 97 participants (age: 56 ± 10 years; 71% female), with 68 in the intervention group (IG; age: 55 ± 8, 77% female) and 29 participants in the control group (CG; age: 59 ± 12, 59% female), were included in the analysis. The baseline characteristics of both groups were comparable, except participants of IG were younger. On average, the PSL at baseline was low in both groups (IG: 9.7 ± 5.4 points; CG: 8.5 ± 6.9 points; p = .165), but 22% (n = 15) in the IG and 20% (n = 6) in the CG reported a high PSL. Most participants reported irregularities in CAR sampling, eg interruption of sleep (IG: 80% CG: 81%). After 8 weeks, most CAR parameters and the PSL decreased in the IG and CG, resulting in no differences of change between the groups. In the IG only, a decrease of PSL was linked to an increase of CAR parameters, eg AUCI (correlation coefficient = −0.307; p = .017). Conclusion: The HLCP may potentially reduce PSL and change the CAR, but results cannot be clearly attributed to the programme. Methodological challenges and multiple confounders, limit suitability of the CAR in the context of lifestyle interventions. Other measures (eg hair-cortisol) may give further insights. Trial registration: German Clinical Trials Register (DRKS); DRKS00018821; www.drks.de

Independent and Joint Impacts of Acid-Producing Diets and Depression on Physical Health among Breast Cancer Survivors

The purpose of this study was to examine the independent and joint associations of acid-producing diets and depressive symptoms with physical health among breast cancer survivors. We studied a cohort of 2944 early stage breast cancer survivors who provided dietary, physical health, demographic, and lifestyle information at baseline, year 1, and year 4. We assessed the intakes of acid-producing diets via two commonly used dietary acid load scores: potential renal acid load (PRAL) and net endogenous acid production (NEAP). Physical health was measured using the Rand 36-Item Short Form Health Survey (SF-36), consisting of physical functioning, role limitation due to physical function, bodily pain, general health, and overall physical health subscales. Increased dietary acid load and depression were each independently and significantly associated with reduced physical health subscales and overall physical health. Further, dietary acid load and depression were jointly associated with worse physical health. For instance, depressed women with dietary acid load higher than median reported 2.75 times the risk (odds ratio = 2.75; 95% confidence interval: 2.18–3.47) of reduced physical function and 3.10 times the risk of poor physical health (odds ratio = 3.10; 95% confidence interval: 2.53–3.80) compared to non-depressed women with dietary acid load lower than median. Our results highlight the need of controlling acid-producing diets and the access of mental care for breast cancer survivors.

Body mass index and variability in hippocampal volume in youth with major depressive disorder

BACKGROUND

The hippocampus has been implicated in major depressive disorder (MDD), in both adults and youth. However, possible sources of variability for the hippocampus have not been well delineated. Here, we explored the relationship between body mass index (BMI) and hippocampal volume in youth with MDD.

METHODS

Twenty-two controls (9 male, 13 female, 12-24 years), 24 youth with MDD and normal BMI (12 male, 12 female, 14-24 years), and 20 youth with MDD and high BMI (14 male, 6 female, 13-22 years) underwent magnetic resonance (MR) imaging and spectroscopy (1H-MRS). Hippocampal volume was determined through manual tracing of high-resolution anatomical T1 scans, and LCModel quantified neurochemical concentrations. Intracranial volume was used as a covariate in analysis to control for effects of brain volume on hippocampus.

RESULTS

In youth with MDD and normal BMI, right hippocampal volume was reduced (p = 0.006, Bonferroni) and a trend for reduced left hippocampal volume was noted when compared to healthy controls (p = 0.054, Bonferroni). Left hippocampal volumes were negatively associated with BMI in youth with MDD and high BMI group (r = -0.593, p = 0.006). No associations were found between the right hippocampus and BMI and there were no group differences for metabolite concentrations.

LIMITATIONS

Larger sample sizes would enable researchers to explore overweight vs obese groups and effect of sex in MDD-BMI groups.

CONCLUSIONS

BMI may account for some of the variability observed in previous studies of hippocampal volume in MDD, and therefore BMI impacts should be considered in future analyses.

Heterogeneity of Endocrinologic and Metabolic Parameters in Reproductive Age Polycystic Ovary Syndrome (PCOS) Women Concerning the Severity of Hyperandrogenemia-A New Insight on Syndrome Pathogenesis

Background: Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, anovulation, infertility, obesity, and insulin resistance, which results in increased concentrations of testosterone (T), which disturbs follicular growth and ovulation. This study aimed to assess PCOS women’s clinical, endocrinological, and metabolic parameters concerning hyperandrogenism severity. Results: 314 women (mean age 27.3 ± 4.6; mean body mass index (BMI) 25.7 ± 5.6) with PCOS, were divided into terciles according to T concentrations: <0.64 ng/mL (group 1), 0.64 to 0.84 ng/mL (Group 2) and >0.84 ng/mL (group 3). The mean concentration of T in all women was 0.59 ng/mL and correlated negatively with the number of menstrual cycles per year (MPY) (r = −0.36; p < 0.0001) and positively with Ferriman-Gallway score (FG) (r = 0.33; p < 0.0001), luteinizing hormone (LH) (r = 0.19; p < 0.0001) and dehydroepiandrosterone sulfate (DHEAS) (r = 0.52; p < 0.0001). Positive correlation between BMI and hirsutism (r = 0.16; p < 0.0001), total cholesterol (TC) (r = 0.18; p < 0.0001), low-density lipoprotein (LDL) (r = 0.29; p < 0.0001), and triglycerides (TG) (r = 0.40; p < 0.0001) was demonstrated. The division into subgroups confirmed the lowest MPY, highest LH, and hirsutism in group 3. BMI, insulin sensitivity indices, and lipid profile parameters were not different between the three T subgroups. Conclusions: We found no correlation between testosterone levels and insulin sensitivity or dyslipidemia in women with PCOS. Metabolic abnormalities may contribute more significantly than hyperandrogenemia to PCOS development.

Immunological and behavioral responses to in vivo lipopolysaccharide administration in young and healthy obese and normal-weight humans

Obesity is associated with an increase prevalence of neuropsychiatric symptoms and diseases, such as depression. Based on the facts that pro-inflammatory cytokines are able to modulate behavior, and that obesity is characterized by a chronic low-grade inflammatory state, inflammation has been hypothesized to contribute to the neuropsychiatric comorbidity in obese individuals. However, a causal link between inflammation and the development of neuropsychiatric symptoms is hard to establish in humans. Here, we used an inflammatory stimulus, i.e. the intravenous injection of lipopolysaccharide (LPS), in a double-blind placebo-controlled design, to determine the vulnerability of obese individuals to inflammation-induced behavioral changes. The hypothesis was that obese individuals would show heightened behavioral response compared to normal-weight subjects for the same inflammatory stimulus, reflecting an increased sensitivity to the behavioral effects of pro-inflammatory cytokines. LPS (dose 0.8 ng/kg body weight, adjusted for estimated blood volume in obese subjects) and placebo (saline) were intravenously injected in 14 obese healthy subjects and 23 normal-weight healthy subjects in a within-subject, randomized, crossover design. LPS administration induced, in both groups, an acute increase in blood concentrations of cytokines (interleukin-6, tumor necrosis factor-α, and IL-10), as well as in body temperature, cortisol, norepinephrine, sickness symptoms, fatigue, negative mood, and state anxiety. There were little differences in the immune and behavioral responses to LPS between obese and normal-weight subjects, but the cortisol response to LPS was strongly attenuated in obese individuals. Higher percentage of body fat was related to a lower cortisol response to LPS. Taken together, the population of young and healthy obese individuals in this study did not exhibit an increased behavioral sensitivity to cytokines, but an attenuated cortisol response to the immune challenge. Future studies will need to determine whether additional physiological and psychological factors interact with the state of obesity to increase the risk for inflammation-induced neuropsychiatric symptoms.

Dialing in the dialogue between inflammation and the brain

The nervous and immune systems communicate with one another and jointly influence functional responses. To highlight the many advances on this hot topic, Brain, Behavior, and Immunity conceptualized a Special Issue entitled "Dialing in the Dialogue Between Inflammation and the Brain." Recent advances and exciting developments in understanding communication pathways between the brain and the immune system during both physiological and pathological insults are highlighted.

Association between C reactive protein and depression in a population of healthy adults: the Cooper Center Longitudinal Study

The relationship between depression and inflammation is currently a topic of much interest. Previous studies have produced mixed results regarding the association between depression and high-sensitivity C reactive protein (hs-CRP). The aim of this report was to determine the association between hs-CRP and depression in a large sample of healthy adults. This is a cross-sectional study of 26,638 healthy adults seen for preventive medical examinations between December 2000 and August 2018 at the Cooper Clinic in Dallas, Texas. Multivariable logistic regression was used to evaluate the association between hs-CRP levels and depressive symptoms as measured by the 10-item Center for Epidemiologic Studies Depression Scale. Covariates included race, age, education, smoking history, alcohol use, menopausal status, body mass index (BMI), and medication use. The Hs-CRP level demonstrated a weakly positive association with depressive symptoms (OR 1.06 per mg/L, 95% CI 1.03 to 1.09 for women; OR 1.05 per mg/L, 95% CI 1.02 to 1.09 for men) that became insignificant when controlling for BMI in women (OR 1.02 per mg/L, 95% CI 0.98 to 1.05) and men (OR 1.02 per mg/L, 95% CI 0.98 to 1.05). Adjusting for antidepressant and statin use did not affect the association between hs-CRP and depressive symptoms in women (OR 0.99 per mg/L, 95% CI 0.96 to 1.03) or men (OR 1.01 per mg/L, 95% CI 0.97 to 1.05). Levels of hs-CRP were not associated with depression independent of BMI in a predominantly white, male population of higher socioeconomic status. This finding suggests that associations between hs-CRP and depression may be explained by obesity, which warrants further investigation into shared pathways between obesity and depression.

Individual differences in glucocorticoid regulation: Does it relate to disease risk and resilience?

Glucocorticoid (GC) signaling varies among individuals, and this variation may relate to individual differences in health outcomes. To determine if and which aspects of signaling (basal, circadian, integrative, or reactivity) are associated with specific health outcomes, we reviewed recent studies that relate GCs to health outcomes. We identified papers through PubMed and reviewed 100 original research articles related to mental health, cardiovascular health, cancer, diabetes, obesity, pulmonary health, sleep, and fitness. Many studies reported elevated GC secretion associated with worse health, but this was only particularly true for integrative GC measures. On the other hand, accentuated cortisol awakening response and a steeper circadian rhythm were both associated with positive health outcomes. Overall, relationships between GC secretion and health outcomes were relatively weak. This systematic review of relationships between GC metrics and health outcomes highlights the importance of careful consideration when selecting methods to measure GC regulation in health research.

Sex-specific roles of cellular inflammation and cardiometabolism in obesity-associated depressive symptomatology

BACKGROUND

Obesity and depression are complex conditions with stronger comorbid relationships among women than men. Inflammation and cardiometabolic dysfunction are likely mechanistic candidates for increased depression risk, and their prevalence differs by sex. Whether these relationships extend to depressive symptoms is poorly understood. Therefore, we analyzed sex in associations between inflammation and metabolic syndrome (MetS) criteria on depressive symptomatology. Specifically, we examined whether sex positively moderates the relationship between depressive symptoms and inflammation among women, and whether MetS has parallel effects among men.

METHODS

Depressive symptoms, MetS, and inflammation were assessed in 129 otherwise healthy adults. Depressive symptoms were assessed using Beck Depression Inventory (BDI-Ia). Monocyte inflammation regulation (BARIC) was quantified using flow cytometry measurement of TNF-α suppression by β-agonist. Moderation effects of sex on associations between BARIC, MetS criteria, and BDI were estimated using two-way ANOVA and linear regression, adjusting for BMI, and by sex subgroup analyses.

RESULTS

Obese individuals reported more depressive symptoms. Sex did not formally moderate this relationship, though BDI scores tended to differ by BMI among women, but not men, in subgroup analysis. Poorer inflammation control and higher MetS criteria were correlated with somatic depressive symptoms. Sex moderated associations between MetS criteria and somatic symptoms; among men, MetS criteria predicted somatic symptoms, not among women. Subgroup analysis further indicated that poorer inflammation control tended to be associated with higher somatic symptoms in women.

CONCLUSIONS

These results indicate that obesity-related inflammation and MetS factors have sex-specific effects on depressive symptoms in a non-clinical population. Although pathophysiological mechanisms underlying sex differences remain to be elucidated, our findings suggest that distinct vulnerabilities to depressive symptoms exist between women and men, and highlight the need to consider sex as a key biological variable in obesity-depression relationships. Future clinical studies on comorbid obesity and depression should account for sex, which may optimize therapeutic strategies.

Early Blood Profile of C57BL/6 Mice Exposed to Chronic Unpredictable Stress

Physiological responses to psychological stressors are protective in acute fight or flight situations; however, there is increasing evidence suggesting the detrimental impact of chronic psychological stress on disease. Chronic stress has been associated with inflammation, poor prognosis, increased morbidity, and poor outcome in many diseases including atherosclerosis, cancer, and pulmonary disease. Given the systemic impact of stress, and the role of the hematopoietic system as a rapid responder to homeostatic insults, we hypothesized that early blood profile changes and biochemical alterations could be detected in a model of chronic stress. To test this hypothesis, a variation of the chronic unpredictable stress (CUS) model was employed. Following 10 days of CUS, C57BL/6 mice exhibited a chronic-stress-associated corticosterone profile. Complete blood count (CBC) revealed mild normochromic, normocytic anemia, and reduced monocyte and lymphocyte count. Serum analysis demonstrated hypoferremia with unchanged total iron binding capacity and serum ferritin levels. These findings are consistent with clinical diagnostic parameters for anemia of chronic disease and indicate that CUS results in significant changes in blood and serum biochemical profile in C57BL/6 mice. These studies identify early changes in blood parameters in response to CUS and identify hematopoietic and biochemical alterations that are often associated with increased morbidity in patients experiencing chronic-stress-associated mental health disease.

Glucocorticoid receptor activation induces decrease of hippocampal astrocyte number in rats

RATIONALE

The decrease of astrocyte number and hypothalamic-pituitary-adrenal (HPA) axis overactivity are observed in individuals with major depressive disorder. Elevated levels of glucocorticoids induced by hyperactivation of the HPA axis may result in glucocorticoid receptor (GR) activation. However, it is unclear whether there is a direct link between GR activation and the decrease of astrocyte number.

METHODS

Animals were exposed to chronic unpredictable stress (CUS) for 28 days and treated with continuous subcutaneous injections of vehicle or corticosterone (CORT; 40 mg/kg/day) for 21 days. We then administered mifepristone on day 21 after CUS and on day 18 after the CORT treatment. We observed behavioral deficits in the sucrose preference test, open field test, and forced swim test. Protein expression was analyzed using immunofluorescence (IF) and western blot (WB).

RESULTS

Animals exposed to CUS exhibited behavioral deficits in tests measuring anhedonia, anxiety, and despair state. They also had decreases in glial fibrillary acidic protein (GFAP) expression and numbers of GFAP-positive cells in the hippocampus. The behavioral and cellular alterations induced by CUS were reversed by subchronic treatment with the GR antagonist mifepristone. We also found that the subcutaneous injection of glucocorticoids may induce depression-like behavior and reduce GFAP protein expression in rats, which was similarly reversed by mifepristone.

CONCLUSIONS

These findings provide experimental evidence that GR activation due to elevated CORT levels induces the decrease of hippocampal astrocyte number in rats.

TLR4-NF-κB Signal Involved in Depressive-Like Behaviors and Cytokine Expression of Frontal Cortex and Hippocampus in Stressed C57BL/6 and ob/ob Mice

Studies found that elevated levels of cytokines such as interleukin- (IL-) 1β, IL-6, and tumor necrosis factor-α (TNF-α) are closely associated with the pathogenesis of depression. Obesity providing a low-grade inflammation state was proposed to be implicated in susceptibility to depression in obesity. However, the alterations of cytokines and the TLR4-NF-κB signal in the brain of normal-weight and obese mice under stress have not been fully elucidated. This study used chronic unpredictable mild stress (CUMS) to induce a depressive-like behavior in an animal model and examine depressive-like behaviors, memory changes, and serum corticosterone levels, as well as the expressions of cytokines and NF-κB in the frontal cortex and hippocampus. We aimed to observe the role of neuroinflammation in susceptibility to depression in obesity under CUMS. In addition, we investigated the protective effect of inhibiting the TLR4-NF-κB signal. Our results demonstrated that CUMS induced depressive-like behavior and spatial memory damage, higher level of serum corticosterone, and overexpression of cytokines and NF-κB in the frontal cortex and hippocampus in both C57BL/6 and ob/ob mice. ob/ob mice displayed serious behavioral disorder and higher levels of IL-1β, IL-6, TNF-α, and NF-κB. Our results concluded that a hyperactive TLR4-NF-κB signal and higher level of cytokines are involved in susceptibility to depression in stressed obese mice.

Acute Strenuous Exercise Induces an Imbalance on Histone H4 Acetylation/Histone Deacetylase 2 and Increases the Proinflammatory Profile of PBMC of Obese Individuals

This study evaluated the response of global histone H4 acetylation (H4ac), histone deacetylase 2 (HDAC2) activity, as well as the production of proinflammatory cytokines and monocyte phenotypes of lean and obese males after exercise. Ten lean and ten obese sedentary men were submitted to one session of strenuous exercise, and peripheral blood mononuclear cells (PBMC) were stimulated in vitro with lipopolysaccharide (LPS). Global H4ac levels, HDAC2 activity in PBMC, and IL-6, IL-8, and TNF-α production were analyzed. Monocyte phenotype was determined in accordance with the expression of CD14 and CD16. At rest, obese individuals presented higher frequency of proinflammatory CD14⁺CD16⁺ monocytes. LPS induced a significant augment in global H4ac and in the production of IL-6, IL-8, and TNF-α mainly in obese individuals. After exercise, the increased production of IL-8 and TNF-α and peripheral frequency of CD14⁺CD16⁺ were observed in both groups. In addition, exercise also induced a significant hyperacetylation of histone H4 and decreased HDAC2 activity in both nonstimulated and LPS-stimulated PBMC of obese individuals. Our data indicate that the obesity impacts on H4ac levels and that strenuous exercise leads to an enhanced chronic low-grade inflammation profile in obesity via an imbalance on H4ac/HDAC2.

Checks and balances: The glucocorticoid receptor and NFĸB in good times and bad

Mutual regulation and balance between the endocrine and immune systems facilitate an organism's stress response and are impaired following chronic stress or prolonged immune activation. Concurrent alterations in stress physiology and immunity are increasingly recognized as contributing factors to several stress-linked neuropsychiatric disorders including depression, anxiety, and post-traumatic stress disorder. Accumulating evidence suggests that impaired balance and crosstalk between the glucocorticoid receptor (GR) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) - effectors of the stress and immune axes, respectively - may play a key role in mediating the harmful effects of chronic stress on mood and behavior. Here, we first review the molecular mechanisms of GR and NFκB interactions in health, then describe potential shifts in the GR-NFκB dynamics in chronic stress conditions within the context of brain circuitry relevant to neuropsychiatric diseases. Furthermore, we discuss developmental influences and sex differences in the regulation of these two transcription factors.

Anxiety independently contributes to elevated inflammation in humans with obesity

OBJECTIVE

Anxious and depressive states are associated with increased cardiovascular disease (CVD) risk and a proinflammatory phenotype, although the latter appears to be at least partially explained by adiposity. It was hypothesized that depression and anxiety would be associated with elevated inflammation independent of adiposity in persons with obesity at high risk of CVD.

METHODS

This study explored the relation between baseline anxiety as measured by the Beck Anxiety Inventory and depression as measured by the Beck Depression Inventory-II and baseline serum c-reactive protein (CRP) in a cross-sectional sample of 100 participants [mean (SD) age 57.8 (7.7) years; 64% female] with obesity [mean (SD) body mass index, BMI 37.3 (5.5) kg/m² ] enrolled in a clinical trial for pharmacological weight loss.

RESULTS

Beck Anxiety Inventory, but not Beck Depression Inventory-II, scores were significantly correlated with CRP (ρ = 0.28, P = 0.005). BMI was also highly correlated with CRP (ρ = 0.42, P < 0.0001). In multivariate models, the relation between anxiety and CRP remained significant (P = 0.038), independent of BMI, age, and sex.

CONCLUSIONS

Anxiety, but not depression, was associated with elevated inflammation in persons with obesity beyond that attributable to higher BMI. Further study is warranted to assess whether anxiety represents a potential therapeutic target to mitigate corresponding CVD risk associated with elevated inflammation in persons with obesity.