Neuroimmunological effects of physical exercise in depression

Values of Cytokines and Tryptophan Metabolites over a 12 Weeks Time Course in Patients with Depression and Somatoform Disorder

Objective

Previous studies have suggested alterations in the kynurenine pathway as a major link between cytokine and neurotransmitter abnormalities in psychiatric disorders. Most of these studies used a cross-sectional case-control study design. However, knowledge is still lacking regarding the stability over time of kynurenine pathway metabolites and the functionally related cytokines. Therefore, we studied the stability of cytokines and tryptophan (TRP) parameters over a period of 12 weeks.

Methods

A total of 117 participants-39 with major depression, 27 with somatoform disorder, and 51 healthy controls were enrolled. Four evaluations, including blood withdrawal and psychometric testing, were performed over a period of 12 weeks. We used ELISA to measure interleukin (IL)-6, IL-1 receptor antagonist (RA) and tumor necrosis factor α (TNF α). High-performance liquid chromatography was used to analyze neurotransmitter variables, i.e. TRP, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), 3-OH-kynurenine (3-HK), and kynurenic acid (KYNA).

Results

We found no significant fluctuations of TRP, its metabolites (5-HIAA, KYN, KYNA, and 3-HK), or the cytokines (IL-1RA, IL-6, and TNF α) in any of the groups over the 12 weeks.

Conclusion

To our knowledge, this is the first longitudinal study performed in psychiatric patients to verify the stability and consequently the reliability of the biological parameters we investigated. Our data indicate that TRP metabolites and cytokines are reliable biological parameters in psychiatric research because they do not fluctuate significantly over time.

Neuroinflammation and cognition across psychiatric conditions

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

Pro-inflammatory Monocyte Phenotype and Cell-Specific Steroid Signaling Alterations in Unmedicated Patients With Major Depressive Disorder

Several lines of evidence have strongly implicated inflammatory processes in the pathobiology of major depressive disorder (MDD). However, the cellular origin of inflammatory signals and their specificity remain unclear. We examined the phenotype and glucocorticoid signaling in key cell populations of the innate immune system (monocytes) vs. adaptive immunity (T cells) in a sample of 35 well-characterized, antidepressant-free patients with MDD and 35 healthy controls individually matched for age, sex, smoking status and body mass index. Monocyte and T cell phenotype was assessed by flow cytometry. Cell-specific steroid signaling was determined by mRNA expression of pre-receptor regulation (11β-hydroxysteroid dehydrogenase type 1; 11β -HSD1), steroid receptor expression [glucocorticoid receptor (GR) and mineralocorticoid receptor (MR)], and the downstream target glucocorticoid-induced leucine-zipper (GILZ). We also collected salivary cortisol samples (8:00 a.m. and 10:00 p.m.) on two consecutive days. Patients showed a shift toward a pro-inflammatory phenotype characterized by higher frequency and higher absolute numbers of non-classical monocytes. No group differences were observed in major T cell subset frequencies and phenotype. Correspondingly, gene expression indicative of steroid resistance (i.e., lower expression of GR and GILZ) in patients with MDD was specific to monocytes and not observed in T cells. Monocyte phenotype and steroid receptor expression was not related to cortisol levels or serum levels of IL-6, IL-1β, or TNF-α. Our results thus suggest that in MDD, cells of the innate and adaptive immune system are differentially affected with shifts in monocyte subsets and lower expression of steroid signaling related genes.

Regular Exercise Modifies Histopathological Outcomes of Pharmacological Treatment in Experimental Autoimmune Encephalomyelitis

Background: Although it has been suggested that healthier lifestyle may optimize effects of the immunomodulation drugs for treating multiple sclerosis (MS), the knowledge regarding this kind of interactions is limited.

Objective: The aim of the present study was to investigate the effects of treadmill exercise in combination with pharmacological treatment in an animal model for MS.

Methods: C57BL/6J female mice were subjected to daily treadmill exercise for 4 weeks before immunization and 6 weeks before clinical presentation of disease. Dimethyl fumarate (DMF) or glatiramer acetate (GA) were administered after the first clinical relapse. Histopathological analyses were carried out in the lumbar spinal cord at peak disease and at 1 or 14 days post-treatment (dpt).

Results: Exercised-GA treated animals demonstrated decreased astrocytic response in the spinal dorsal horn with an improvement in the paw print pressure. Exercised-DMF treated animals showed an increased microglial/macrophage response on both ventral and dorsal horn that were associated with clinical improvement and synaptic motoneuron inputs density.

Conclusion: The present data suggest that prior regular exercise can modify the effects of pharmacological treatment administered after the first relapse in a murine model for MS.

The effect of exercise on resting concentrations of peripheral brain-derived neurotrophic factor (BDNF) in major depressive disorder: A meta-analysis

Exercise interventions have been shown to successfully improve depression in patients with major depressive disorder (MDD), but like other forms of antidepressant treatment, exercise is not effective in all patients and its mechanisms of action have not been fully elucidated. Brain-derived neurotrophic factor (BDNF), a key mediator of neurogenesis and neuronal survival, has been shown to be decreased in individuals with MDD. One potential mechanism by which exercise alleviates depression is through an increase in BDNF. In order to evaluate this hypothesis, we conducted a meta-analysis of studies that assessed the effects of a chronic (multi-week) exercise intervention on BDNF concentrations in MDD patients. MEDLINE, Embase, PsycINFO, SPORTDiscus, Rehabilitation & Sports Medicine Source, and CINAHL databases were searched for original, peer-reviewed reports of peripheral blood BDNF concentrations before and after a chronic exercise intervention in MDD patients. Standardized mean differences (SMDs) were generated from random effects models. Potential sources of heterogeneity were explored in meta-regression analyses. In six studies that met inclusion criteria, resting blood concentrations of BDNF were not significantly higher after a chronic exercise intervention (SMD = 0.43, 95% CI: -0.06-0.92, p = 0.09) in MDD patients. This meta-analysis did not find evidence that a chronic aerobic exercise intervention increases resting concentrations of BDNF in the blood of MDD patients; however, there is a lack of studies in this area making it difficult to reach a definitive conclusion. Future studies on this topic with larger sample sizes and longer durations are needed to draw more robust conclusions.

Crocin, a natural product attenuates lipopolysaccharide-induced anxiety and depressive-like behaviors through suppressing NF-kB and NLRP3 signaling pathway

Depression is one of the foremost psychological illness which is closely leagued with inflammation. Crocin is a natural product that exhibits both anti-inflammatory and anti-oxidant activities. However, little is known about anti-inflammatory mechanisms of crocin on LPS-induced anxiety and depressive-like behaviors. The objective of this study is emphasized on neuroprotective role of crocin against LPS-induced anxiety and depressive-like behaviors in mice. It is observed that crocin inhibited LPS-induced production of NO, TNF-α, IL-1β and ROS in BV-2 microglial cells. Moreover, crocin significantly declined the expression of iNOS, NF-κB p65 and CD16/32 (M1 marker), as well as elevated the expression of CD206 (M2 marker) in BV-2 cell line with decreased LPS-induced anxiety and depressive-like behaviors by improved locomotor activity, reduced sucrose intake, and decreased immobility time in forced swim and tail suspension test in Kunming mice. Expression of NLRP3, ASC and caspase-1 by i.p administration of LPS found to be neutralized with reduction in level of IL-1β, IL-18 and TNF-α in mouse hippocampus. In conclusion, these results suggested that crocin as a potential therapeutic candidate for neuro-inflammation and depressive-like behaviors induced by LPS. The effect was found to be due to inhibition of NLRP3 inflammasome and NF-κB and its promoted M1 to M2 phenotypic conversion of microglia.

Immune-based strategies for mood disorders: facts and challenges

INTRODUCTION

Inflammation seems to play a role in the pathophysiology of mood disorders, including major depressive disorder (MDD) and bipolar disorder (BD). In the last years several studies have shown increased levels of inflammatory and/or immune markers in patients with mood disorders. Accordingly, the immune system has become a target of interest for the development of biomarkers and therapeutics for mood disorders. Areas covered: Here, we review the evidence showing low-grade inflammation in mood disorders and the studies evaluating immune-based strategies for the treatment of these conditions. Expert commentary: Clinical trials with non-steroidal anti-inflammatory drugs, polyunsaturated acids, N-acetylcysteine, anti-cytokines, physical activity and probiotics have provided promising results in terms of antidepressant efficacy in patients with MDD and BD. Regarding stem cells, only studies with animal models have been performed so far with interesting pre-clinical results. Due to the preliminary nature of the results, most of the clinical studies need to be replicated and/or confirmed in larger clinical settings, embracing the highly heterogeneous pathophysiology of mood disorders.

Reduced muscle mass in middle-aged depressed patients is associated with male gender and chronicity

OBJECTIVE

Reduced muscle mass is a characteristic finding in sarcopenia, the central element of physical frailty syndrome, and a major cause of physical function decay, morbidity and mortality in the elderly. Studies so far demonstrated reduced muscle mass in depressed patients with an average age over 60years. An open question is whether muscle mass reduction is already observed earlier. Therefore, muscle mass was assessed in middle-aged male and female depressive patients, and the findings were related to indicators of hypothalamus-pituitary adrenal axis activation, lifestyle factors, endocrine and immune measures.

METHODS

Sixty-seven depressed patients (mean age 38.6y; 58.2% female) and 26 healthy volunteers (mean age 40.5y; 61.5% female) were included. Muscle mass, adrenal gland volume, and intra-abdominal adipose tissue were assessed by magnetic resonance tomography. Laboratory parameters included fasting cortisol, pro-inflammatory cytokines, factors constituting the metabolic syndrome, and relative insulin resistance according to the homeostasis model assessment (HOMA-IR).

RESULTS

We found significant effects of depression (F=4.2; P=0.043) and gender (F=182; P<0.001) on muscle mass. Muscle mass was reduced in depressed men compared to healthy men (F=3.4; P=0.044), particularly in those with chronic depression. In contrast, no such association was observed in depressed females. Adrenal gland volume and intra-abdominal fat was increased in depressed men and women, although not significantly. Correlations were observed for muscle mass with the amount of self-reported exercise and depression severity, and for depression severity with self-reported exercise. Further findings comprised lower self-reported activity and higher cortisol concentrations in depressed male and female compared to healthy probands.

CONCLUSIONS

Muscle mass is reduced in middle-aged depressed men, particularly those with chronic disease course. This association is not observed in depressed females, possibly pointing to the role of female sex steroids in maintaining muscle mass. The increase of adrenal gland volume in depressed patients may point to the role of a dysregulated hypothalamus-pituitary-adrenal system. The inverse association of exercise with muscle mass demonstrates the importance of physical activity. Looking at the long term consequences of reduced muscle mass, interventions to preserve and rebuild muscle mass in depression - such as structured exercise interventions - should be recommended.

SIGNIFICANT OUTCOMES

Muscle mass is decreased in male patients with major depressive disorder, particular those with chronic disease course. This difference was not observed in female depressed patients. The extent of muscle mass reduction is correlated to depression severity and inversely to physical activity, pointing to the role of depression associated inactivity. Low muscle mass is a risk factor for physical frailty, therefore interventions aiming at improving physical fitness may be recommended.

LIMITATIONS

Sex steroids were not assessed in the study groups.

Sit, step, sweat: longitudinal associations between physical activity patterns, anxiety and depression

BACKGROUND

Physical inactivity has been identified as a risk factor for depression and, less often, as a long-term consequence of depression. Underexplored is whether similar bi-directional longitudinal relationships are observed for anxiety disorders, particularly in relation to three distinct indicators of activity levels - sports participation, general physical activity and sedentary behavior.

METHOD

Participants were from the Netherlands Study of Depression and Anxiety (NESDA; N = 2932, 18-65 years old; 57% current anxiety or depressive disorder, 21% remitted disorder, 22% healthy controls). At baseline, 2, 4, and 6 years, participants completed a diagnostic interview and self-report questionnaires assessing psychopathology symptom severity, physical activity indicators, and sociodemographic and health covariates.

RESULTS

Consistently across assessment waves, people with anxiety and/or depressive disorders had lower sports participation and general physical activity compared to healthy controls. Greater anxiety or depressive symptoms were associated with lower activity according to all three indicators. Over time, a diagnosis or greater symptom severity at one assessment was associated with poorer sports participation and general physical activity 2 years later. In the opposite direction, only low sports participation was associated with greater symptom severity and increased odds of disorder onset 2 years later. Stronger effects were observed for chronicity, with lower activity according to all indicators increasing the odds of disorder chronicity after 2 years.

CONCLUSIONS

Over time, there seems to a mutually reinforcing, bidirectional relationship between psychopathology and lower physical activity, particularly low sports participation. People with anxiety are as adversely affected as those with depression.

Factors Associated With Functional Capacity in Hemodialysis Patients

Hemodialysis patients have a marked decrease in functional capacity when compared to healthy individuals. We evaluated the factors associated with functional capacity in hemodialysis patients. A total of 102 hemodialysis patients were evaluated. The patients were submitted to a 6-min walk test, peripheral muscle strength tests, and an evaluation of quality of life, anxiety, and depression. The laboratory data were measured. The 6-min walk test distance correlated significantly with age, educational level, hemoglobin, creatinine, number of comorbidities, peripheral muscle strength, and some domains of SF-36 quality of life questionnaire and depression (P < 0.05). Multiple linear regression showed that educational level, hemoglobin, peripheral muscle strength, and depression significantly affected the 6-min walk test distance (P < 0.05). The multiple correlation coefficient was 0.74, and the squared multiple correlation coefficient adjusted was 0.52. In conclusion, functional capacity was significantly associated with educational level, hemoglobin, peripheral muscle strength, and depression in hemodialysis patients.

Interleukin-6 and depressive symptom severity in response to physical exercise

Elevated IL-6 has been implicated in depression. The anti-inflammatory effects of exercise may be associated with its clinical efficacy for depression. We determined if serum IL-6 levels were altered by 12 weeks of physical exercise, and if IL-6 levels were associated with baseline depression severity and change in depression severity in response to exercise. Data from 116 adults (42.7±11.5y) with mild-to-moderate depression (Patient Health Questionnaire >9) who participated in the physical exercise arm of the Regassa RCT (www.regassa.se) were analyzed. Participants were requested to complete three 60-min exercise sessions weekly for 12 weeks. Blood samples were provided at baseline and post-intervention following an overnight fast and were analyzed for serum levels of IL-6 using ELISA. IL-6 values were logarithm-transformed. Higher baseline serum IL-6 levels were significantly associated with reduced depression severity after exercise. Reduced IL-6 levels following exercise were significantly associated with parallel reductions in depression severity. These findings are consistent with a previously reported association between reduced serum IL-1β levels and reduced depression severity following 12 weeks of physical exercise in 105 depressed adults. Findings support associations between IL-6, depressive symptoms, and exercise response, and provide support for the plausible involvement of IL-6 in the antidepressive effect of exercise.

Activation of P2X7 receptor and NLRP3 inflammasome assembly in hippocampal glial cells mediates chronic stress-induced depressive-like behaviors

Background

In recent years, proinflammatory cytokine interleukin-1β (IL-1β) was considered to play a critical role in the pathogenesis of depression. In addition, P2X7 receptor (P2X7R), a member of the purinergic receptor family, which is predominantly present on microglia, as well as on astrocytes and neurons in lesser amounts in the central nervous system, was suggested to be involved in the processing and releasing of IL-1β. Here, we investigated the role of P2X7R in the pathogenesis of depression.

Methods

Male Sprague-Dawley rats were subjected to chronic unpredictable stressors (CUS) for 3 weeks. At the end of week 1, 2, and 3, extracellular ATP, caspase 1, IL-1β, and components and activation of NLRP3 inflammasome (nucleotide-binding, leucine-rich repeat, pyrin domain containing 3) were evaluated as biomarker of neuroinflammation. In separate experiments, the rats were microinjected with P2X7R agonists ATP, BzATP, and saline into the hippocampus, respectively, or exposed to CUS combined with hippocampal microinjection with P2X7R antagonist, BBG and A438079, and saline, respectively, for 3 weeks, followed by exposed to forced swimming test and open-field test. Moreover, we also evaluated the depressive and anxiety-like behavior of P2X7-null mice in forced swimming test, open-field test, and elevated plus maze.

Results

Along with stress accumulation, extracellular ATP, cleaved-caspase 1, IL-1β, and ASC were significantly enhanced in the hippocampus, but P2X7R and NLRP3 were not. Immunoprecipitation assay indicated that along with the accumulation of stress, assembly of NLRP3 inflammasome and cleaved caspase 1 in NLRP3 inflammasome were significantly increased. Moreover, antagonists of P2X7R, either BBG or A438079, prevented the development of depressive-like behaviors induced by chronic unpredictable stress in rats. Meanwhile, we could not observe any depressive-like or anxiety-like behaviors of P2X7-null mice after they had been exposed to CUS. The results implied that P2X7 knockout could impede the development of depressive-like and anxiety-like behaviors induced by CUS. In contrast, chronic administration of agonists of P2X7R, either ATP or BzATP, could induce depressive-like behaviors.

Conclusions

The activation of P2X7R and subsequent NLRP3 inflammasome in hippocampal microglial cells could mediate depressive-like behaviors, which suggests a new therapeutic target for the prevention and treatment of depression.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0865-y) contains supplementary material, which is available to authorized users.

Contribution of neuroinflammation and immunity to brain aging and the mitigating effects of physical and cognitive interventions

It is widely accepted that the brain and the immune system continuously interact during normal as well as pathological functioning. Human aging is commonly accompanied by low-grade inflammation in both the immune and central nervous systems, thought to contribute to many age-related diseases. This review of the current literature focuses first on the normal neuroimmune interactions occurring in the brain, which promote learning, memory and neuroplasticity. Further, we discuss the protective and dynamic role of barriers to neuroimmune interactions, which have become clearer with the recent discovery of the meningeal lymphatic system. Next, we consider age-related changes of the immune system and possible deleterious influences of immunosenescence and low-grade inflammation (inflammaging) on neurodegenerative processes in the normally aging brain. We survey the major immunomodulators and neuroregulators in the aging brain and their highly tuned dynamic and reciprocal interactions. Finally, we consider our current understanding of how physical activity, as well as a combination of physical and cognitive interventions, may mediate anti-inflammatory effects and thus positively impact brain aging.

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

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

Long-lasting effects of fluoxetine and/or exercise augmentation on bio-behavioural markers of depression in pre-pubertal stress sensitive rats

Juvenile depression is of great concern with only limited treatment currently approved. Delayed onset of action, low remission and high relapse rates, and potential long-lasting consequences further complicates treatment and highlights the need for new treatment options. Studies reporting on long-lasting effects of early-life treatment have reported conflicting results, with the pre-adolescent period mostly overlooked. The anti-depressive effect of exercise, as a possible treatment option or augmentation strategy, is dependent on age and exercise intensity. We investigated the immediate (i.e. postnatal day 35 (PND35)) and lasting (PND60 to PND61) effects of pre-pubertal (PND21 to PND34) fluoxetine and/or exercise on bio-behavioural markers of depression and oxidative stress in stress sensitive Flinders Sensitive Line rats. Low, but not moderate, intensity exercise or 5, but not 10, mg/kg/day fluoxetine displayed anti-depressant-like properties at PND35. Pre-pubertal treatment with 5mg/kg/day fluoxetine or low intensity exercise exerted lasting anti-depressive-like effects into adulthood, whereas the combination of these two treatments did not. Furthermore, the combination of fluoxetine plus exercise reduced hippocampal BDNF levels as compared to exercise alone, which may explain the latter findings. In all treatment groups hippocampal SOD activity was significantly increased at PND61, suggesting an increased anti-oxidant capacity in adulthood. In conclusion, the data confirm the anti-depressant-like properties of both early-life fluoxetine and exercise in a genetic animal model of depression. However, optimal lasting effects of early-life interventions may require adjustment of antidepressant dose and/or exercise intensity to developmental age, and that a combination of antidepressant and exercise may not necessarily be augmentative.

Walking away from depression-motor activity increases ratings of mood and incentive drive in patients with major depression

Reduced motor activity is associated with depression. Lewinsohn's cognitive behavioural model of depression assumes a lack of positive experience due to a reduced level of activity as a key aspect of depression. The acute relationship between motor activity and mood as well as between motor activity and incentive drive (the motivation to engage in activities) is unknown. An augmentation of mood and incentive drive could precede or follow motor activity. We examined (1) whether motor activity would be correlated with the course of depression and (2) the temporal relationship between motor activity and acute changes in mood and incentive drive. Motor activity was measured with actigraphy in 12 patients with depression for one week. Severity of depression was assessed before and at the end of the study with depression rating scales. The patients reported mood and incentive drive once per hour. With lag sequential analysis, the temporal relationship between motor activity and mood and incentive drive was evaluated. Higher motor activity was associated with depression improvement. Motor activity had an acute association with mood and incentive drive, especially one hour after activity. The results support the Lewinsohn's model of depression and underline the impact of behavioural activation in antidepressant treatment.

A Longitudinal Investigation of Anxiety and Depressive Symptomatology and Exercise Behaviour Among Adults With Type 2 Diabetes Mellitus

OBJECTIVES

Evidence suggests that symptoms of depression and anxiety predict lower exercise behaviour and, inversely, that less exercise predicts higher symptomatology. The present longitudinal study examined this reciprocal association in adults with type 2 diabetes mellitus. We predicted that symptoms of anxiety or depression would intensify over time as a consequence of lower exercise frequency and, similarly, that exercise frequency would decrease as a consequence of greater symptoms of anxiety or depression.

METHODS

We studied 1691 adults with type 2 diabetes who provided baseline measures in 2011 and 2 subsequent annual assessments (Follow-up 1 and Follow-up 2). Symptoms of depression and anxiety were measured using the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder-7, respectively. A single item assessed exercise frequency in the past month (in days).

RESULTS

Separate 3-wave cross-lagged path models for symptoms of anxiety and depression tested the reciprocal associations. Contrary to our hypotheses, the reciprocal associations were not supported and, by extension, the predicted secondary associations were not tested. In sum, only depressive symptoms negatively predicted subsequent exercise frequency (Follow-up 1 and Follow-up 2).

CONCLUSIONS

Symptoms of depression were prospectively associated with lower exercise frequency, which is consistent with evidence from population-based studies that identify depressive symptoms as a barrier to exercise participation.

The Anti-Inflammatory Effects of Blueberries in an Animal Model of Post-Traumatic Stress Disorder (PTSD)

Post-traumatic stress disorder (PTSD) is a trauma and stressor-related disorder that results in a prolonged stress response. It is associated with increased oxidative stress and inflammation in the prefrontal cortex (PFC) and hippocampus (HC). The only approved therapy for PTSD is selective serotonin re-uptake inhibitors (SSRIs), but their efficacy is marginal. Recently, we demonstrated that over-production of norepinephrine (NE) as the possible reason for the lack of efficacy of SSRIs. Hence, there is a need for novel therapeutic approaches for the treatment of PTSD. In this study, we investigated the anti-inflammatory role of blueberries in modulating inflammatory markers and neurotransmitter levels in PTSD. Rats were fed either a blueberry enriched (2%) or a control diet. Rats were exposed to cats for one hour on days 1 and 11 of a 31-day schedule to simulate traumatic conditions. The rats were also subjected to psychosocial stress via daily cage cohort changes. At the end of the study, the rats were euthanized and the PFC and HC were isolated. Monoamines were measured by high-performance liquid chromatography. Reactive oxygen species (ROS), gene and protein expression levels of inflammatory cytokines were also measured. In our PTSD model, NE levels were increased and 5-HT levels were decreased when compared to control. In contrast, a blueberry enriched diet increased 5-HT without affecting NE levels. The rate limiting enzymes tyrosine hydroxylase and tryptophan hydroxylase were also studied and they confirmed our findings. The enhanced levels free radicals, gene and protein expression of inflammatory cytokines seen in the PTSD group were normalized with a blueberry enriched diet. Decreased anxiety in this group was shown by improved performance on the elevated plus-maze. These findings indicate blueberries can attenuate oxidative stress and inflammation and restore neurotransmitter imbalances in a rat model of PTSD.

IMPROVEMENTS IN PSYCHOSOCIAL FUNCTIONING AND HEALTH-RELATED QUALITY OF LIFE FOLLOWING EXERCISE AUGMENTATION IN PATIENTS WITH TREATMENT RESPONSE BUT NONREMITTED MAJOR DEPRESSIVE DISORDER: RESULTS FROM THE TREAD STUDY

BACKGROUND

Functional impairments often remain despite symptomatic improvement with antidepressant treatment, supporting the need for novel treatment approaches. The present study examined the extent to which exercise augmentation improved several domains of psychosocial functioning and quality of life (QoL) among depressed participants.

METHODS

Data were collected from 122 partial responders to antidepressant medication. Participants were randomized to either high- (16 kcal/kg of weight/week [KKW]) or low-dose (4-KKW) exercise. Participants completed a combination of supervised and home-based exercise for 12 weeks. The Short-Form Health Survey, Work and Social Adjustment Scale, Social Adjustment Scale, Quality of Life Enjoyment and Satisfaction Questionnaire, and Satisfaction with Life Scale were collected at 6 and 12 weeks. Participants with data for at least one of the two follow-up time points (n = 106) were analyzed using a linear mixed model to assess change from baseline within groups and the difference between groups for each psychosocial outcome measure. All analyses controlled for covariates, including baseline depressive symptomatology.

RESULTS

Participants experienced significant improvements in functioning across tested domains, and generally fell within a healthy range of functioning on all measures at Weeks 6 and 12. Although no differences were found between exercise groups, improvements were observed across a variety of psychosocial and QoL domains, even in the low-dose exercise group.

CONCLUSIONS

These findings support exercise augmentation of antidepressant treatment as a viable intervention for treatment-resistant depression to improve function in addition to symptoms.

Oxidative Stress Implications in the Affective Disorders: Main Biomarkers, Animal Models Relevance, Genetic Perspectives, and Antioxidant Approaches

The correlation between the affective disorders and the almost ubiquitous pathological oxidative stress can be described in a multifactorial way, as an important mechanism of central nervous system impairment. Whether the obvious changes which occur in oxidative balance of the affective disorders are a part of the constitutive mechanism or a collateral effect yet remains as an interesting question. However it is now clear that oxidative stress is a component of these disorders, being characterized by different aspects in a disease-dependent manner. Still, there are a lot of controversies regarding the relevance of the oxidative stress status in most of the affective disorders and despite the fact that most of the studies are showing that the affective disorders development can be correlated to increased oxidative levels, there are various studies stating that oxidative stress is not linked with the mood changing tendencies. Thus, in this minireview we decided to describe the way in which oxidative stress is involved in the affective disorders development, by focusing on the main oxidative stress markers that could be used mechanistically and therapeutically in these deficiencies, the genetic perspectives, some antioxidant approaches, and the relevance of some animal models studies in this context.

Influence of Exercise Intensity for Improving Depressed Mood in Depression: A Dose-Response Study

INTRODUCTION

Exercise effectively improves mood in major depressive disorder (MDD), but the optimal exercise stimulus to improve depressed mood is unknown.

PURPOSE

To determine the dose-response relationship of acute exercise intensity with depressed mood responses to exercise in MDD. We hypothesized that the acute response to exercise would differ between light, moderate, and hard intensity exercise with higher intensities yielding more beneficial responses.

METHODS

Once weekly, 24 women (age: 38.6±14.0) diagnosed with MDD underwent a 30-minute session at one of three steady-state exercise intensities (light, moderate, hard; rating of perceived exertion 11, 13 or 15) or quiet rest on a stationary bicycle. Depressed mood was evaluated with the Profile of Mood States before, 10 and 30 minutes post-exercise.

RESULTS

Exercise reduced depressed mood 10 and 30 minutes following exercise, but this effect was not influenced by exercise intensity. Participants not currently taking antidepressants (n=10) had higher baseline depression scores, but did not demonstrate a different antidepressant response to exercise compared to those taking antidepressants.

CONCLUSIONS

To acutely improve depressed mood, exercise of any intensity significantly improved feelings of depression with no differential effect following light, moderate, or hard exercise. Pharmacological antidepressant usage did not limit the mood-enhancing effect of acute exercise. Acute exercise should be used as a symptom management tool to improve mood in depression, with even light exercise an effective recommendation. These results need to be replicated and extended to other components of exercise prescription (e.g., duration, frequency, mode) to optimize exercise guidelines for improving depression.

Deficiencies of the T and natural killer cell system in major depressive disorder: T regulatory cell defects are associated with inflammatory monocyte activation

BACKGROUND

In a previous study, we found an up-regulated inflammatory monocyte gene expression profile in major depressive disorder (MDD) patients aged ⩾ 28 years and a down-regulated inflammatory gene expression profile in MDD patients aged<28 years. In the same sample of patients, we aimed to investigate immune dysregulation in the lymphocyte arm of the immune system, particularly in the context of the described monocyte (de-)activation states.

METHODS

From deep frozen leukocytes, circulating percentages of monocytes, lymphocytes, B, T, and natural killer (NK) cells, and various functional subsets of T and T helper (Th) cells (Th1, Th2, Th17, and natural T regulatory cells) were measured in N=50 MDD patients and N=58 age- and gender-matched healthy controls (HC). In addition, serum levels of interleukin (IL)-6, sCD25, IL-7, IL-3, SCF, IGF-BP2, and EGF were evaluated.

RESULTS

MDD patients were in general characterized by an impaired maturation of Th2 cells, Th17 cells, and NK cells and by decreased serum levels of IL-7 and sCD25. MDD patients aged ⩾ 28 years additionally exhibited decreased percentages of CD4(+)CD25(high)FoxP3(+) T regulatory cells, next to signs of the above described partial T cell defects. Natural T regulatory cells were inversely associated with the pro-inflammatory state of the monocytes (r=-.311; p=.034) that characterized this patient subgroup.

CONCLUSIONS

Deficiencies of the NK and T (regulatory) cell system and inflammatory monocyte immune activation co-occur as partly interrelated phenomena within the same MDD patients.

Physical activity and exercise attenuate neuroinflammation in neurological diseases

Major depressive disorder (MDD), schizophrenia (SCH), Alzheimer's disease (AD), and Parkinson's disease (PD) are devastating neurological disorders, which increasingly contribute to global morbidity and mortality. Although the pathogenic mechanisms of these conditions are quite diverse, chronic neuroinflammation is one underlying feature shared by all these diseases. Even though the specific root causes of these diseases remain to be identified, evidence indicates that the observed neuroinflammation is initiated by unique pathological features associated with each specific disease. If the initial acute inflammation is not resolved, a chronic neuroinflammatory state develops and ultimately contributes to disease progression. Chronic neuroinflammation is characterized by adverse and non-specific activation of glial cells, which can lead to collateral damage of nearby neurons and other glia. This misdirected neuroinflammatory response is hypothesized to contribute to neuropathology in MDD, SCH, AD, and PD. Physical activity (PA), which is critical for maintenance of whole body and brain health, may also beneficially modify neuroimmune responses. Since PA has neuroimmune-modifying properties, and the common underlying feature of MDD, SCH, AD, and PD is chronic neuroinflammation, we hypothesize that PA could minimize brain diseases by modifying glia-mediated neuroinflammation. This review highlights current evidence supporting the disease-altering potential of PA and exercise through modifications of neuroimmune responses, specifically in MDD, SCH, AD and PD.

Depression, body mass index, and chronic obstructive pulmonary disease - a holistic approach

Background

Several clinical studies suggest common underlying pathogenetic mechanisms of COPD and depressive/anxiety disorders. We aim to evaluate psychopathological and physical effects of aerobic exercise, proposed in the context of pulmonary rehabilitation, in a sample of COPD patients, through the correlation of some psychopathological variables and physical/pneumological parameters.

Methods

Fifty-two consecutive subjects were enrolled. At baseline, the sample was divided into two subgroups consisting of 38 depression-positive and 14 depression-negative subjects according to the Hamilton Depression Rating Scale (HAM-D). After the rehabilitation treatment, we compared psychometric and physical examinations between the two groups.

Results

The differences after the rehabilitation program in all assessed parameters demonstrated a significant improvement in psychiatric and pneumological conditions. The reduction of BMI was significantly correlated with fat mass but only in the depression-positive patients.

Conclusion

Our results suggest that pulmonary rehabilitation improves depressive and anxiety symptoms in COPD. This improvement is significantly related to the reduction of fat mass and BMI only in depressed COPD patients, in whom these parameters were related at baseline. These findings suggest that depressed COPD patients could benefit from a rehabilitation program in the context of a multidisciplinary approach.

Health Behaviors, Knowledge, Life Satisfaction, and Wellbeing in People with Mental Illness across Four Countries and Comparisons with Normative Sample

BACKGROUND

People with chronic mental illness have poorer physical health and higher mortality than the general population. We investigated lifestyle factors in people with mental illness across four countries and compared with a normative sample.

DESIGN AND METHODS

Data were collected from N = 672 people (Germany, n = 375; Palestine, n = 192; London, n = 63; Australia, n = 42) with substance abuse disorder (n = 224), schizophrenia (n = 158), mood disorders (n = 227), and somatoform disorders (n = 63). The General Health Behaviour Questionnaire measured behaviors and knowledge related to nutrition, physical activity, alcohol, smoking, sleep, life satisfaction, and wellbeing. The normative samples were derived from a German population (N = 1,019). Data were analyzed using ANOVAs and t-tests.

RESULTS

The Palestine sample did not differ from the Western samples on reported life satisfaction and wellbeing. However, they reported unhealthier diets, less physical activity, and lower knowledge about the impact of diet, physical activity, smoking, and sleep on health than the Western samples. Comparing the Western and normative samples, people with mental illness reported lower intake of healthy foods/drinks, higher intake of unhealthy foods, higher exercise, higher alcohol consumption, less cigarettes, less sleep, and more sleep problems. Their knowledge was lower for nutrition, physical activity, and smoking. All participants reported lower life satisfaction and wellbeing than the normative sample (P-values <0.001).

CONCLUSION

Education on health-related lifestyle factors present important targets for primary care, quality of life and prevention of illness in people with mental illness. Further research will clarify specific predictors of health behaviors in each country.

Factors affecting daily physical activity and physical performance in maintenance dialysis patients

Maintenance hemodialysis (MHD) patients display reduced daily physical activity (DPA) and physical performance (PP). Previous studies did not differentiate the effects of kidney failure and MHD treatments from comorbidities as causes for reduced DPA and PP. In relatively healthy MHD patients and normal adults, we evaluated DPA and PP and examined relationships between DPA and PP and possible associations between anxiety or depression and DPA and PP. DPA, 6-minute walk distance (6-MWD), sit-to-stand (STS), and stair-climbing tests were measured in 72 MHD patients (40% diabetics) with limited comorbidities and 39 normal adults of similar age and gender mix. Anxiety and depression were measured by the Beck anxiety and depression inventories. DPA, time-averaged over 7 days, and all 3 PP tests were impaired in MHD patients, to about 60% to 70% of normal values (P < .0001 for each measurement). MHD patients spent more time sleeping or physically inactive (P < .0001) and less time in ≥ moderate activity (P < .0001). Adjusted DPA correlated with 6-MWD but not STS or stair-climbing. Anxiety and depression were identified in 43% and 33% of MHD patients and 2.5% and 5.1% of normals (P < .0001 for each comparison). Most of the impairment in DPA and PP tests were also observed in MHD patients without anxiety or depression. However, MHD patients with both anxiety and depression generally had the most impaired DPA and PP. In MHD patients, higher adjusted anxiety scores were correlated with impaired 6-MWD and STS, whereas adjusted average DPA was negatively correlated with depression (r = -0.33, P = .006) but not anxiety. DPA on the hemodialysis day (P = .01), day after dialysis (P = .03), and day 2 after dialysis (P = .03) each correlated negatively with degree of depression but not with anxiety. MHD patients displayed negative-adjusted correlations between anxiety and 6-MWD (P = .03) and STS (P = .04). In relatively healthy MHD patients, DPA and PP are substantially impaired and correlated with each other, even in patients without evidence for anxiety or depression. Anxiety and depression are common in MHD patients and are associated with further impairment in DPA and PP.

Neurobiological effects of exercise on major depressive disorder: A systematic review

Exercise displays promise as an efficacious treatment for people with depression. However, no systematic review has evaluated the neurobiological effects of exercise among people with major depressive disorder (MDD). The aim of this article was to systematically review the acute and chronic biological responses to exercise in people with MDD. Two authors conducted searches using Medline (PubMed), EMBASE and PsycINFO. From the searches, twenty studies were included within the review, representing 1353 people with MDD. The results demonstrate that a single bout of exercise increases atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), copepetin and growth hormone among people with MDD. Exercise also potentially promotes long-term adaptations of copeptin, thiobarbituric acid reactive species (TBARS) and total mean frequency (TMF). However, there is limited evidence that exercise promotes adaptations on neurogenesis, inflammation biomarkers and brain structure. Associations between depressive symptoms improvement and hippocampus volume and IL-1β were found. Nevertheless, the paucity of studies and limitations presented within, precludes a more definitive conclusion of the underlying neurobiological explanation for the antidepressant effect of exercise in people with MDD. Further trials should utilize appropriate assessments of neurobiological markers in order to build upon the results of our review and further clarify the potential mechanisms associated with the antidepressant effects of exercise.

IL-8 and the innate immunity as biomarkers in acute child and adolescent psychopathology

OBJECTIVE

The role of inflammation in psychopathology has received great attention over the past decades. Immune system dysfunction and altered cytokine levels have been reported in most psychiatric disorders in adults. Few data are available regarding children and adolescents (C&A), or regarding the relationship between cytokine levels and psychosocial stress. This study investigates the profile of the most described cytokines in a sample of C&A inpatients affected by an acute psychiatric condition requiring hospitalization, in comparison with healthy subjects, as well as possible associations between psychosocial stressors and psychopathology and/or cytokine concentrations.

METHODS

Patients with a diagnosis of Affective, Anxiety, Adjustment, Psychotic, Obsessive-Compulsive, Tic or Tourette Disorders were consecutively recruited from our clinic between June 2010 and February 2012. Controls were recruited from the same geographic area. All subjects were between 8 and 17 years old. Twelve cytokines are compared: interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL_10, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IFN-γ-induced protein-10 (IP-10), monocyte chemoattractant protein (MCP)-1. Psychosocial stress was measured through the Stressful Life Events Scale, Child and Parents versions (SLES-C and SLES-P) and the evaluation of the family integrity.

RESULTS

One hundred and eleven subjects (77C&A inpatients and 34 healthy controls), of which 54 were males (49%), with a median (interquartile range) age of 16 (13.7-17.3) years, were included in this study. IL-1β, IL6, IL8, IP-10, MCP-1 and monocytes were found to be significantly higher in the patient group (p<0.05). Differences were confirmed when adjusting by BMI, age, gender and drug intake at admission for all cytokines except MCP-1. IL-8 and IL-1β were also higher throughout the different diagnostic categories, than in control group (p<0.05). Stress measures were higher in patients. A significant correlation was found between stress measured by the SLES and some inflammatory markers: SLES_C with IL-1β, IL-8, MCP-1, and SLES_P with IL-1β and monocytes absolute and relative counts (Spearman's r between 0.219 and 0.297, p<0.05). Logistic regression identified the following variables as independent predictors of the patient condition, (odds ratio per quartile, p-value): IL8 (1, 0.9, 12.1, 32.0, p=0.044), IP10 (1, 14.1, 2.5, 3.7, p=0.044), monocyte absolute count (1, 1.1, 6.0, 19.4, p=0.030).

CONCLUSIONS

Results show elevated inflammation markers from the innate immune system across C&A acute psychiatric diagnosis, and suggest a link between psychopathology, inflammation and stress. Inflammatory markers resulted predictors of patient status. These exploratory results are coherent with current psychoneuroimmunology and neurodevelopmental investigations.

Exercise training for managing behavioral and psychological symptoms in people with dementia: A systematic review and meta-analysis

This systematic review and meta-analysis of randomized controlled trials assessed the effects of exercise on behavioral and psychological symptoms of dementia (BPSD, including depression) in people with dementia (PWD). Secondary outcomes for the effects of exercise were mortality and antipsychotic use. Twenty studies were included in this review (n=18 in the meta-analysis). Most studies used a multicomponent exercise training (n=13) as intervention; the control group was often a usual care (n=10) or a socially-active (n=8) group. Exercise did not reduce global levels of BPSD (n=4. Weighted mean difference -3.884; 95% CI -8.969-1.201; I(2)=69.4%). Exercise significantly reduced depression levels in PWD (n=7). Standardized mean difference -0.306; 95% CI -0.571 to -0.041; I(2)=46.8%); similar patterns were obtained in sensitivity analysis performed among studies with: institutionalized people (p=0.038), multicomponent training (p=0.056), social control group (p=0.08), and low risk of attrition bias (p=0.11). Exploratory analysis showed that the principal BPSD (other than depression) positively affected by exercise was aberrant motor behavior. Exercise had no effect on mortality. Data on antipsychotics were scarce. In conclusion, exercise reduces depression levels in PWD. Future studies should examine whether exercise reduces the use (and doses) of antipsychotics and other drugs often used to manage BPSD.

Organ-specific physiological responses to acute physical exercise and long-term training in humans

Virtually all tissues in the human body rely on aerobic metabolism for energy production and are therefore critically dependent on continuous supply of oxygen. Oxygen is provided by blood flow, and, in essence, changes in organ perfusion are also closely associated with alterations in tissue metabolism. In response to acute exercise, blood flow is markedly increased in contracting skeletal muscles and myocardium, but perfusion in other organs (brain and bone) is only slightly enhanced or is even reduced (visceral organs). Despite largely unchanged metabolism and perfusion, repeated exposures to altered hemodynamics and hormonal milieu produced by acute exercise, long-term exercise training appears to be capable of inducing effects also in tissues other than muscles that may yield health benefits. However, the physiological adaptations and driving-force mechanisms in organs such as brain, liver, pancreas, gut, bone, and adipose tissue, remain largely obscure in humans. Along these lines, this review integrates current information on physiological responses to acute exercise and to long-term physical training in major metabolically active human organs. Knowledge is mostly provided based on the state-of-the-art, noninvasive human imaging studies, and directions for future novel research are proposed throughout the review.

Optimizing the Exercise Prescription for Depression: The Search for Biomarkers of Response

There is growing support for the efficacy of exercise interventions for the treatment of individuals who present with mild-to-moderate depression. The variability in treatment response across studies and individuals suggests that the efficacy of exercise for depression will be most optimal when prescribed to individuals who are most prone to respond. The present article reviews contemporary theoretical accounts and recent empirical data pointing to neuroinflammatory states and neurotrophin production as possible biomarkers of the antidepressant response to exercise. The larger exercise and depression literatures provide justification for elevated levels of pro-inflammatory cytokines and deficits in BDNF production as putative matching variables. Although there is some empirical support for these hypotheses, it is clear that this research warrants replication and extension. We offer a few suggestions for future research in this emerging area.

Exercise and severe major depression: effect on symptom severity and quality of life at discharge in an inpatient cohort

BACKGROUND

Exercise is a potential treatment for depression. However, few studies have evaluated the role of adjunct exercise in the treatment of severely major depressed inpatients. The goal of this study was to evaluate the effects of add-on exercise on the usual treatment of severely depressed inpatients.

METHODS

Fifty participants were randomized to an exercise (exercise + usual treatment) or a control (usual treatment) group. Twenty-five patients were randomly allocated to each group. The participants in the exercise group performed three sessions per week throughout the hospitalization period, with a goal dose of 16.5 kcal/kg/week plus the usual pharmacological treatment. Depressive symptoms and the Quality of Life (QoL) of the participants were assessed at the baseline, the second week, and discharge.

RESULTS

A significant group × time interaction was found for depressive symptoms and the physical and psychological domains of QoL. Differences between groups occurred at the second week and discharge with respect to depressive symptoms and the physical and psychological domains of QoL. There was no difference in the remission rate at discharge (48% and 32% for the exercise and control group, respectively). An NNT of 6.25 was found. No significant baseline characteristics predict remission at discharge.

CONCLUSION

Add-on exercise is an efficacious treatment for severely depressed inpatients, improving their depressive symptoms and QoL. Initial acceptance of exercise remains a challenge.

Effects of Physical Exercise on Neuroinflammation, Neuroplasticity, Neurodegeneration, and Behavior: What We Can Learn From Animal Models in Clinical Settings

Physical exercise is a cornerstone in the management of many neurodegenerative disorders, such as Parkinson's disease, dementia, and stroke. However, much of its beneficial effects on improving motor functions and cognition as well as decreasing neurodegeneration and neuroinflammation are not yet well understood. The obvious limitations of studying the protective mechanisms behind exercise, for example, brain plasticity and neurodegeneration, could be overcome by generating novel animal models of neurodegenerative disorders. In this narrative review, we discuss the beneficial effects of exercise performed in animal models of neurodegenerative disorders and how the results from animal studies can be used in clinical settings. From preclinical studies, the positive effects of exercise have been related to increased levels of neurotrophic factors, elevated expression of anti-inflammatory cytokines, and reduced levels of pro-inflammatory cytokines and activated microglia. It is clear that parameters influencing the effect of exercise, such as intensity, still remain to be investigated in animal studies in order to find the optimal program that can be translated into exercise interventions for patients with neurodegenerative diseases.

The impacts of swimming exercise on hippocampal expression of neurotrophic factors in rats exposed to chronic unpredictable mild stress

Depression is associated with stress-induced neural atrophy in limbic brain regions, whereas exercise has antidepressant effects as well as increasing hippocampal synaptic plasticity by strengthening neurogenesis, metabolism, and vascular function. A key mechanism mediating these broad benefits of exercise on the brain is induction of neurotrophic factors, which instruct downstream structural and functional changes. To systematically evaluate the potential neurotrophic factors that were involved in the antidepressive effects of exercise, in this study, we assessed the effects of swimming exercise on hippocampal mRNA expression of several classes of the growth factors (BDNF, GDNF, NGF, NT-3, FGF2, VEGF, and IGF-1) and peptides (VGF and NPY) in rats exposed to chronic unpredictable mild stress (CUMS). Our study demonstrated that the swimming training paradigm significantly induced the expression of BDNF and BDNF-regulated peptides (VGF and NPY) and restored their stress-induced downregulation. Additionally, the exercise protocol also increased the antiapoptotic Bcl-xl expression and normalized the CUMS mediated induction of proapoptotic Bax mRNA level. Overall, our data suggest that swimming exercise has antidepressant effects, increasing the resistance to the neural damage caused by CUMS, and both BDNF and its downstream neurotrophic peptides may exert a major function in the exercise related adaptive processes to CUMS.

Inflammasomes in neuroinflammation and changes in brain function: a focused review

Recent literature has pointed to the existence of inflammasome-mediated inflammatory pathways in central nervous system (CNS) disorders and associated changes in behavior. Neuroinflammation, which is an innate immune response in the CNS against harmful and irritable stimuli such as pathogens and metabolic toxic waste, as well as to chronic mild stress, is mediated by protein complexes known as inflammasomes. Inflammasomes activate pro-inflammatory caspases 1 and 5, which then cleave the precursor forms of pro-inflammatory cytokines IL-1β, IL-18, and IL-33 into their active forms. These pro-inflammatory cytokines have been shown to promote a variety of innate immune processes associated with infection, inflammation, and autoimmunity, and thereby play an instrumental role in the instigation of neuroinflammation during old age and subsequent occurrence of neurodegenerative diseases, cognitive impairment, and dementia. In particular, NLRP inflammasomes may also have a role in the etiologies of depression, Alzheimer's disease (AD) and in metabolic disorders, such as Type II diabetes, obesity and cardiovascular diseases that have been shown to be co-morbid with psychiatric illnesses. It has been reported that while these inflammasomes may be activated through TNF-α dependent pathways, other cytokines, like IFN-γ, may assist in inhibiting their activation and thus delay disease progression. Furthermore, some other cytokines, including IL-6, may not have a direct role in inflammasome-mediated diseases. An array of recent research suggests that NLRP inflammasomes targeted therapies could be used for alleviating neuroinflammation and for treatment of associated psychiatric illnesses, although this still remains a challenge and necessitates further extensive research. This review examines the complex inflammatory signaling pathways involved in the activation of NLRP inflammasomes and the role they play in promoting neuroinflammation and subsequent behavioral changes.

A phase-specific neuroimmune model of clinical depression

Immune dysfunction and pro-inflammatory states in particular have been implicated in the aetiology and pathogenesis of depression. Whilst the onset of an episode and certain symptoms of depression appear well explained by this inflammatory model, the underpinnings of the episodic and progressive nature, as well as relapse and remission status in depression require attention. In this review it is suggested that additional immune factors beyond pro- and anti-inflammatory cytokines may effectively contribute to the understanding of the neurobiology of clinical depression. Considering neurobiological effects of immunomodulatory factors such as T cells, macrophages, microglia and astrocytes relevant to depression, we suggest a neuroimmune model of depression underpinned by dynamic immunomodulatory processes. This perspective paper then outlines a neuroimmune model of clinical phases of depression in an attempt to more adequately explain depression-like behaviours in pre-clinical models and the dynamic nature of depression in clinical populations. Finally, the implications for immunomodulatory treatments of depression are considered.

Blunted exercise-induced mobilization of monocytes in somatization syndromes and major depression

BACKGROUND

Previous research indicates that physical activity may alter the number of immune cells. We examined whether increasing or decreasing the level of physical activity affects circulating lymphocyte and monocyte counts in patients with somatization syndromes and patients with major depression.

METHODS

Thirty-eight participants with major depression, 26 participants with somatization syndromes and 47 healthy controls participated in the study. Using an experimental within-subject design, participants were involved in 1 week of increased physical activity (daily exercise sessions) and 1 week of reduced physical activity. Counts of total lymphocytes, lymphocyte subsets and monocytes were determined before and after each trial. Linear mixed models adjusted for sex, body mass index, age, fitness status and the order of trials were used for longitudinal data analysis.

RESULTS

One week of exercise increases the number of monocytes in healthy controls (p<.05), but not in patients with somatization syndromes or patients with major depression. In addition, after 1 week of exercise, depressive symptoms were reduced in patients with major depression (p<.05) while somatoform symptoms were reduced (p<.05) in both clinical groups. Baseline comparisons and mixed models indicated reduced T helper cell counts in patients with somatization syndromes.

LIMITATIONS

Relatively small sample size. The time of physical activity was relatively short and restricted to low-graded exercise.

CONCLUSIONS

This study demonstrates a blunted mobilization of monocytes by exercise in both patients with somatization syndromes and patients with major depression. In addition, even one week of exercise reduces somatoform and depressive symptoms.

Inflamed moods: a review of the interactions between inflammation and mood disorders

Mood disorders have been recognized by the World Health Organization (WHO) as the leading cause of disability worldwide. Notwithstanding the established efficacy of conventional mood agents, many treated individuals continue to remain treatment refractory and/or exhibit clinically significant residual symptoms, cognitive dysfunction, and psychosocial impairment. Therefore, a priority research and clinical agenda is to identify pathophysiological mechanisms subserving mood disorders to improve therapeutic efficacy. During the past decade, inflammation has been revisited as an important etiologic factor of mood disorders. Therefore, the purpose of this synthetic review is threefold: 1) to review the evidence for an association between inflammation and mood disorders, 2) to discuss potential pathophysiologic mechanisms that may explain this association and 3) to present novel therapeutic options currently being investigated that target the inflammatory-mood pathway. Accumulating evidence implicates inflammation as a critical mediator in the pathophysiology of mood disorders. Indeed, elevated levels of pro-inflammatory cytokines have been repeatedly demonstrated in both major depressive disorder (MDD) and bipolar disorder (BD) patients. Further, the induction of a pro-inflammatory state in healthy or medically ill subjects induces 'sickness behavior' resembling depressive symptomatology. Potential mechanisms involved include, but are not limited to, direct effects of pro-inflammatory cytokines on monoamine levels, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, pathologic microglial cell activation, impaired neuroplasticity and structural and functional brain changes. Anti-inflammatory agents, such as acetyl-salicylic acid (ASA), celecoxib, anti-TNF-α agents, minocycline, curcumin and omega-3 fatty acids, are being investigated for use in mood disorders. Current evidence shows improved outcomes in mood disorder patients when anti-inflammatory agents are used as an adjunct to conventional therapy; however, further research is needed to establish the therapeutic benefit and appropriate dosage.

Small vessel disease and memory loss: what the clinician needs to know to preserve patients' brain health

Small vessel disease (SVD) in the brain manifests in the periventricular and deep white matter and radiographically is described as "leukoaraiosis". It is increasingly recognized as a cause of morbidity from middle age onward and this clinical relevance has paralleled advances in the field of neuroradiology. Overall, SVD is a heterogenous group of vascular disorders that may be asymptomatic, or a harbinger of many conditions that jeopardize brain health. Management and prevention focuses on blood pressure control, lifestyle modification, and symptomatic treatment.

Oxidative & nitrosative stress in depression: why so much stress?

Many studies support a crucial role for oxidative & nitrosative stress (O&NS) in the pathophysiology of unipolar and bipolar depression. These disorders are characterized inter alia by lowered antioxidant defenses, including: lower levels of zinc, coenzyme Q10, vitamin E and glutathione; increased lipid peroxidation; damage to proteins, DNA and mitochondria; secondary autoimmune responses directed against redox modified nitrosylated proteins and oxidative specific epitopes. This review examines and details a model through which a complex series of environmental factors and biological pathways contribute to increased redox signaling and consequently increased O&NS in mood disorders. This multi-step process highlights the potential for future interventions that encompass a diverse range of environmental and molecular targets in the treatment of depression.

Relation between anxiety, depression, and physical activity and performance in maintenance hemodialysis patients

OBJECTIVE

Maintenance hemodialysis (MHD) patients have a high prevalence of anxiety and depression and decreased daily physical activity (DPA) and exercise capacity. Because affective disorders may affect DPA and physical performance, we investigated possible relationships between anxiety or depression and DPA and physical performance in relatively healthy MHD patients.

DESIGN AND METHODS

This cross-sectional study included 72 relatively healthy MHD patients and 39 normal adults. DPA was measured for 7 days with an Actigraph Activity Monitor®. Physical performance was assessed using the 6-minute walk (6-MWT), sit-to-stand (STS), and stair-climbing tests. Subjects completed the Beck Anxiety Inventory (BAI), the Beck Depression Inventory-II (BDI), and the Hospital Anxiety and Depression Scale (HADS). Main outcome measures were physical activity counts (expressed as vector magnitude), in the 6-MWT, STS, stair-climbing test, BAI, BDI, and HADS scores.

RESULTS

Anxiety and depression by BAI and BDI were identified in 43% and 33% of MHD patients and 2.5% and 5% of normals, respectively (P < .0001 for each comparison). MHD patients without anxiety or depression had decreased DPA and physical performance compared with normals, indicating that these disorders were also independent of anxiety or depression. MHD patients with anxiety and depression generally had the most impaired DPA and physical performance. Higher BAI and BDI scores were each associated with impaired physical performance. In fully adjusted analyses, DPA in MHD patients was negatively correlated with the BDI (r = -0.33, P = .01) but not with the BAI. DPA on the day of hemodialysis (P = .01), and day 1 (P = .03) and day 2 (P = .03) after dialysis each correlated negatively with degree of depression by BDI. In MHD patients, BAI was negatively correlated with 6-MWT (P = .03) and STS (P = .04).

CONCLUSIONS

In relatively healthy adult MHD patients, anxiety and depression are common and are associated with impaired physical performance. There was a trend toward stronger negative associations between BDI scores and DPA than between BAI scores and DPA.

Cellular and molecular mechanisms of immunomodulation in the brain through environmental enrichment

Recent studies on environmental enrichment (EE) have shown cytokines, cellular immune components [e.g., T lymphocytes, natural killer (NK) cells], and glial cells in causal relationship to EE in bringing out changes to neurobiology and behavior. The purpose of this review is to evaluate these neuroimmune mechanisms associated with neurobiological and behavioral changes in response to different EE methods. We systematically reviewed common research databases. After applying all inclusion and exclusion criteria, 328 articles remained for this review. Physical exercise (PE), a form of EE, elicits anti-inflammatory and neuromodulatory effects through interaction with several immune pathways including interleukin (IL)-6 secretion from muscle fibers, reduced expression of Toll-like receptors on monocytes and macrophages, reduced secretion of adipokines, modulation of hippocampal T cells, priming of microglia, and upregulation of mitogen-activated protein kinase phosphatase-1 in central nervous system. In contrast, immunomodulatory roles of other enrichment methods are not studied extensively. Nonetheless, studies showing reduction in the expression of IL-1β and tumor necrosis factor-α in response to enrichment with novel objects and accessories suggest anti-inflammatory effects of novel environment. Likewise, social enrichment, though considered a necessity for healthy behavior, results in immunosuppression in socially defeated animals. This has been attributed to reduction in T lymphocytes, NK cells and IL-10 in subordinate animals. EE through sensory stimuli has been investigated to a lesser extent and the effect on immune factors has not been evaluated yet. Discovery of this multidimensional relationship between immune system, brain functioning, and EE has paved a way toward formulating environ-immuno therapies for treating psychiatric illnesses with minimal use of pharmacotherapy. While the immunomodulatory role of PE has been evaluated extensively, more research is required to investigate neuroimmune changes associated with other enrichment methods.

Physical activity and mental health in women with polycystic ovary syndrome

Background

Physical activity is prescribed as a component of primary management for Polycystic Ovary Syndrome (PCOS). This study investigates the association between physical activity and mental health as well as the exercise barriers, motivators and support providers for younger women with and without PCOS to assist in physical activity uptake and prescription for these women.

Methods

Women aged 18-50 years with (n = 153) and without PCOS (n = 64) completed a questionnaire at one time point. The questionnaire included the Hospital Anxiety and Depression Scale and a survey regarding levels of physical activity, physical activity barriers, motivators and supports. A MANCOVA assessed associations between physical activity, PCOS and mental health (specifically depression and anxiety). Descriptive and Chi square goodness of fit statistics assessed the differences in perceived barriers, motivators and support providers amongst women with and without PCOS.

Results

Women with PCOS displayed higher severity of depression (F(1,210) = 8.32, p = 0.004) and anxiety (F(1,210) = 17.37, p < 0.001) symptoms compared to controls. Overall, for physically active women, depression was significantly less severe than in their inactive counterparts (F(2,210) = 13.62, p < 0.001). There were no differences in anxiety by physical activity status and no interaction effects between PCOS and activity status for depression or anxiety. Women with PCOS were more likely to report a lack of confidence about maintaining physical activity (Χ² = 3.65; p = 0.046), fear of injury (Χ² = 4.08; p = 0.043) and physical limitations (Χ² = 11.92; p = 0.001) as barriers to physical activity and were more likely to be motivated to be active to control a medical condition (Χ² = 7.48; p = 0.006). Women with PCOS identified more sources of support compared to women without PCOS.

Conclusions

Physical activity is associated with lower depression in women with PCOS and differences exist in the self-reported physical activity barriers, motivators and support providers, compared to controls. Being more active may offer mental health benefits in managing PCOS. Prescribing physical activity to women with PCOS should be individualized and consider both common and PCOS-specific barriers and motivators for successful engagement.

Exercise as an intervention for sedentary hazardous drinking college students: A pilot study

Young adults 18-24 years have the highest rates of problems associated with alcohol use among all age groups, and substance use is inversely related to engagement in substance-free activities. This pilot study investigated the promotion of one specific substance-free activity, exercise, on alcohol use in college students. Thirty-one sedentary college students who engaged in hazardous drinking (Alcohol Use Disorders Identification Test scores ≥ 8) were randomized to one of two conditions: (a) one 50-minute session of motivational enhancement therapy (MET) focused on increasing exercise, or (b) one 50-minute session of MET focused on increasing exercise plus 8 weeks of contingency management (CM) for adhering to specific exercise activities. All participants completed evaluations at baseline and post-treatment (2-months later) assessing exercise participation and alcohol use. Results of the pilot study suggest the interventions were well received by participants, the MET+CM condition showed an increased self-reported frequency of exercise in comparison to the MET alone condition, but other indices of exercise, physical fitness, and alcohol use did not differ between the interventions over time. These results suggest that a larger scale trial could better assess efficacy of this well received combined intervention. Investigation in other clinically relevant populations is also warranted.