Neuroimmunological effects of physical exercise in depression

Environmental enrichment enhances the antidepressant effect of ketamine and ameliorates spatial memory deficits in adult rats

Ketamine is a rapid-acting antidepressant associated with various cognitive side effects. To mitigate these side effects while enhancing efficacy, it can be co-administered with other antidepressants. In our study, we adopted a similar strategy by combining ketamine with environmental enrichment, a potent sensory-motor paradigm, in adult male Wistar rats. We divided the animals into four groups based on a combination of housing conditions and ketamine versus vehicle injections. The groups included those housed in standard cages or an enriched environment for 50 days, which encompassed a 13-day-long behavioral testing period. Each group received either two doses of ketamine (20 mg/kg, IP) or saline as a vehicle. We tested the animals in the novel object recognition test (NORT), forced swim test (FST), open field test (OFT), elevated plus maze (EPM), and Morris water maze (MWM), which was followed by ex vivo c-Fos immunohistochemistry. We observed that combining environmental enrichment with ketamine led to a synergistic antidepressant effect. Environmental enrichment also ameliorated the spatial memory deficits caused by ketamine in the MWM. There was enhanced neuronal activity in the habenula of the enrichment only group following the probe trial of the MWM. In contrast, no differential activity was observed in enriched animals that received ketamine injections. The present study showed how environmental enrichment can enhance the antidepressant properties of ketamine while reducing some of its side effects, highlighting the potential of combining pharmacological and sensory-motor manipulations in the treatment of mood disorders.

Running exercise improves astrocyte loss, morphological complexity and astrocyte-contacted synapses in the hippocampus of CUS-induced depression model mice

Although the antidepressant effects of running exercise have been widely reported, further research is still needed to determine the structural bases for these effects. Astrocyte processes physically contact many synapses and directly regulate the numbers of synapses, but it remains unclear whether running exercise can modulate astrocyte morphological complexity and astrocyte-contacted synapses in the hippocampus of the mice with depressive-like behavior. Male C57BL/6 J mice underwent four weeks of running exercise after four weeks of chronic unpredictable stress (CUS). The sucrose preference test (SPT), tail suspension test (TST) and forced swim test (FST) were used to assess anhedonia in mice. Western blotting was used to measure the expression of astrocyte- and synapse-related proteins. Immunofluorescence and 3D reconstruction were used to quantify the density and morphology of astrocytes, and astrocyte-contacted synapses in each hippocampal subregion. Four weeks of running exercise alleviated depressive-like symptoms in mice. The expression of astrocyte- and synapse-related proteins in the hippocampus; astrocyte process lengths, process numbers, and dendritic arborization; and the number of astrocyte-contacted PSD95 positive synapses in the CA2-3 and DG regions were significantly decreased in the mice with depressive-like behavior, and running exercise successfully reserved these changes. Running exercise improved the decreases in astrocyte morphological complexity and astrocyte-contacted PSD95 positive synapses in the CA2-3 and DG regions of the mice with depressive-like behavior, suggesting that the physical interactions between astrocytes and synapses can be increased by running exercise, which might be an important structural basis for the antidepressant effects of running exercise.

The Economics of Treatment for Depression

The global prevalence of depression has risen over the past three decades across all socioeconomic groups and geographic regions, with a particularly rapid increase in prevalence among adolescents (aged 12-17 years) in the United States. Depression imposes large health, economic, and societal costs, including reduced life span and quality of life, medical costs, and reduced educational attainment and workplace productivity. A wide range of treatment modalities for depression are available, but socioeconomic disparities in treatment access are driven by treatment costs, lack of culturally tailored options, stigma, and provider shortages, among other barriers. This review highlights the need for comparative research to better understand treatments' relative efficacy, cost-effectiveness, scalability, and potential heterogeneity in efficacy across socioeconomic groups and country and cultural contexts. To address the growing burden of depression, mental health policy could consider reducing restrictions on the supply of providers, implementing digital interventions, reducing stigma, and promoting healthy lifestyles.

Glitches in the brain: the dangerous relationship between radiotherapy and brain fog

Up to approximately 70% of cancer survivors report persistent deficits in memory, attention, speed of information processing, multi-tasking, and mental health functioning, a series of symptoms known as "brain fog." The severity and duration of such effects can vary depending on age, cancer type, and treatment regimens. In particular, every year, hundreds of thousands of patients worldwide undergo radiotherapy (RT) for primary brain tumors and brain metastases originating from extracranial tumors. Besides its potential benefits in the control of tumor progression, recent studies indicate that RT reprograms the brain tumor microenvironment inducing increased activation of microglia and astrocytes and a consequent general condition of neuroinflammation that in case it becomes chronic could lead to a cognitive decline. Furthermore, radiation can induce endothelium reticulum (ER) stress directly or indirectly by generating reactive oxygen species (ROS) activating compensatory survival signaling pathways in the RT-surviving fraction of healthy neuronal and glial cells. In particular, the anomalous accumulation of misfolding proteins in neuronal cells exposed to radiation as a consequence of excessive activation of unfolded protein response (UPR) could pave the way to neurodegenerative disorders. Moreover, exposure of cells to ionizing radiation was also shown to affect the normal proteasome activity, slowing the degradation rate of misfolded proteins, and further exacerbating ER-stress conditions. This compromises several neuronal functions, with neuronal accumulation of ubiquitinated proteins with a consequent switch from proteasome to immunoproteasome that increases neuroinflammation, a crucial risk factor for neurodegeneration. The etiology of brain fog remains elusive and can arise not only during treatment but can also persist for an extended period after the end of RT. In this review, we will focus on the molecular pathways triggered by radiation therapy affecting cognitive functions and potentially at the origin of so-called "brain fog" symptomatology, with the aim to define novel therapeutic strategies to preserve healthy brain tissue from cognitive decline.

Running exercise alleviates hippocampal neuroinflammation and shifts the balance of microglial M1/M2 polarization through adiponectin/AdipoR1 pathway activation in mice exposed to chronic unpredictable stress

Running exercise has been shown to alleviate depressive symptoms. However, the mechanism underlying the antidepressant effects of running exercise is not fully understood. The imbalance of M1/M2 microglia phenotype/polarization and concomitant dysregulation of neuroinflammation play crucial roles in the pathogenesis of depression. Running exercise increases circulating levels of adiponectin which is known to cross the blood‒brain barrier and suppress inflammatory responses. AdipoR1 is an adiponectin receptor that is involved in regulating microglial phenotypes and activation states. However, whether running exercise regulates hippocampal microglial phenotypes and neuroinflammation through adiponectin/AdipoR1 to exert its antidepressant effects remains unclear. In the current study, 4 weeks of running exercise significantly alleviated the depressive-like behaviors of chronic unpredictable stress (CUS)-exposed mice. Moreover, running exercise decreased the microglial numbers and altered microglial morphology in three subregions of the hippocampus to restore the M1/M2 balance; these effects were accompanied by regulation of pro-/anti-inflammatory cytokine production and secretion in CUS-exposed mice. These effects may involve elevation of peripheral tissue (adipose tissue and muscle) and plasma adiponectin levels, and hippocampal AdipoR1 levels as well as activation of the AMPK-NF-κB/STAT3 signaling pathway by running exercise. When an adeno-associated virus was used to knock down hippocampal AdipoR1, mice showed depressive-like behaviors and alterations in microglia and inflammatory factor expression in the hippocampus that were similar to those observed in CUS-exposed mice. Together, these results suggest that running exercise maintains the M1/M2 balance and inhibits neuroinflammation in the hippocampus of CUS-exposed mice. These effects might occur via adiponectin/AdipoR1-mediated activation of the AMPK-NF-κB/STAT3 signaling pathway.

Alterations in gut microbiota caused by major depressive disorder or a low FODMAP diet and where they overlap

Beneficial changes in microbiota observed in individuals with a major depressive disorder (MDD) may be initiated with a low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) elimination diet. Academic Search Ultimate, APA PsychINFO, Cochrane Library, MEDLINE, Scopus and Web of Science were searched for original research documenting differences in microbiota in MDD or changes with a low FODMAP diet in adults (age 18 years +). Studies with fecal microbiota, 16 s RNA sequencing and QIIME pipelines were included. Studies using antibiotics, probiotics, and medications such as antidepressants were excluded. Additionally, studies based on a single gender were excluded as gender impacts microbiota changes in MDD. Four studies addressed differences in microbiota with MDD and another four assessed shifts occurring with a low FODMAP diet. The abundance of Bacteroidetes, Bacteroidaceae and Bacteroides were lower in individuals with MDD but increased with a low FODMAP diet. Abundance of Ruminoccaceae was lower and Bilophila was higher with both a low FODMAP diet and MDD. These results provide preliminary evidence that a low FODMAP diet might drive changes in microbiota that also benefit people with MDD. Further research to assess whether a low FODMAP diet can treat MDD through modification of targeted microbiota is warranted.

High workload is related to lower quality of life in public school teachers: A cross-sectional study

BACKGROUND

People with long work hours, as evidenced by teachers, were more likely to present health problems that impact their quality of life (QoL). The reduced physical activity (PA) level or higher sedentary behavior in public school teachers was related to obesity. Although PA seems to improve the QoL in other professions, assessing whether the PA level could influence the relationship between workload and QoL in public school teachers is necessary.

OBJECTIVE

To analyze whether the high workload was related to worse QoL in teachers considered less active and more active.

METHODS

Two hundred forty-three teachers from public schools participated in this study. The domains of QoL and PA levels were assessed by SF-36 and Baecke questionnaires, respectively. Workload perception was assessed by a Likert scale. Binary logistic regression analyzed the association between high workload and QoL domains in teachers considering the PA level in a model adjusted by confounding factors (i.e., sex, age, and socioeconomic condition).

RESULTS

Heavy workload was associated with less chances of having better physical limitation domain of both less and more physically active teachers. Less active teachers with heavy workloads were 53%, 61%, and 56% less likely to have better vitality, social functioning, and mental health, respectively. No such associations were observed in the more physically active teachers.

CONCLUSION

Less active teachers with a heavy workload demonstrate lower QoL. Although the PA practice eliminated this relationship, both active and less active teachers with a heavy workload demonstrated lower QoL in physical limitation domain.

Altered Expression of Astrocytic ATP Channels and Ectonucleotidases in the Cerebral Cortex and Hippocampus of Chronic Social Defeat Stress-Susceptible BALB/c Mice

The increasing number of patients with depressive disorder is a serious socioeconomic problem worldwide. Although several therapeutic agents have been developed and used clinically, their effectiveness is insufficient and thus discovery of novel therapeutic targets is desired. Here, focusing on dysregulation of neuronal purinergic signaling in depressive-like behavior, we examined the expression profiles of ATP channels and ectonucleotidases in astrocytes of cerebral cortex and hippocampus of chronic social defeat stress (CSDS)-susceptible BALB/c mice. Mice were exposed to 10-d CSDS, and their astrocytes were obtained using a commercially available kit based on magnetic activated cell sorting technology. In astrocytes derived from cerebral cortex of CSDS-susceptible mice, the expression levels of mRNAs for connexin 43, P2X7 receptors and maxi anion channels were increased, those for connexin 43 and P2X7 receptors being inversely correlated with mouse sociability, and the expression of mRNAs for ecto-nucleoside triphosphate diphosphohydrase 2 and ecto-5'nucleotidase was decreased and increased, respectively. On the other hand, the alteration profiles of ATP channels and ectonucleotidases in hippocampal astrocytes of CSDS-susceptible mice were different from in the case of cortical astrocytes, and there was no significant correlation between expression levels of their mRNAs and mouse sociability. These findings imply that increased expression of ATP channels in cerebral cortex might be involved in the development of reduced sociability in CSDS-subjected BALB/c mice. Together with recent findings, it is suggested that ATP channels expressed by cortical astrocytes might be potential therapeutic targets for depressive disorder.

Effect of public square dancing combined with serotonin reuptake inhibitors on persistent postural-perceptual dizziness (PPPD) in middle-aged and older women

BACKGROUND

Persistent postural-perceptual dizziness (PPPD) is a functional vestibular disorder that causes chronic dizziness and limits daily activities. Although pharmacology, vestibular rehabilitation, and cognitive behavioral therapy have been proposed to have some efficacy, they have certain limitations. Some patients with PPPD report that public square dancing can effectively relieve the symptoms of dizziness and instability, and their mood improves.

OBJECTIVE

To evaluate the effects of combining public square dancing with serotonin reuptake inhibitors (SSRIs/SNRIs) on the subjective sensations of dizziness, balance enhancement, anxiety, and depressive symptom regulation in middle-aged and older women with PPPD.

MATERIALS AND METHODS

In this trial, 124 patients diagnosed with PPPD were enrolled. Among them, 64 patients were randomly assigned to the experimental group (EG), where they received square dance training combined with serotonin reuptake inhibitors. The remaining 60 cases were randomly assigned to the control group (CG), where they received only serotonin reuptake inhibitors and did not participate in organized sports activities, allowing them freedom in their daily lives. Data from the Dizziness Handicap Inventory (DHI), Hospital Anxiety and Depression Scale (HADS), Active-specific Balance Confidence Scale (ABC), and Vestibular Disorder Activities of Daily Living Scale (VADL) were collected and compared at the beginning, 3 months, and 6 months of the trial to evaluate the effect of public square dancing on middle-aged and older women with PPPD.

RESULTS

There were no significant differences between the EG and CG before the trial. Compared with baseline measures, DHI, HADS, ABC, and VADL scores improved as the experiment progressed, and the improvements were more pronounced in the EG.

CONCLUSION

Public square dancing combined with serotonin reuptake inhibitors has a positive impact on the subjective sensations of dizziness, balance enhancement, anxiety, and depressive symptom regulation in middle-aged and older women with PPPD.

Running from depression: the antidepressant-like potential of prenatal and pre-pubertal exercise in adolescent FSL rats exposed to an early-life stressor

OBJECTIVE

We aimed to answer the questions of whether early-life (perinatal and/or juvenile) exercise can induce antidepressant-like effects in a validated rodent model of depression, and whether such early-life intervention could prevent or reverse the adverse effects of early-life stress in their offspring.

METHODS

Male and female Flinders sensitive line rats born to a dam that exercised during gestation, or not, were either maternally separated between PND02 and 16 and weaned on PND17 or not. Half of these animals then underwent a fourteen-day low-intensity exercise regimen from PND22. Baseline depressive-like behaviour was assessed on PND21 and then reassessed on PND36, whereafter hippocampal monoamine levels, redox state markers and metabolic markers relevant to mitochondrial function were measured.

RESULTS

Pre-pubertal exercise was identified as the largest contributing factor to the observed effects, where it decreased immobility time in the FST by 6%, increased time spent in the open arms of the EPM by 9%. Hippocampal serotonin and norepinephrine levels were also increased by 35% and 26%, respectively, whilst nicotinic acid was significantly decreased.

CONCLUSION

These findings suggest that pre-pubertal low-intensity exercise induces beneficial biological alterations that could translate into antidepressant behaviour in genetically susceptible individuals.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

The Muscle-Gut-Brain Axis and Psychiatric Illness

The microbiota-gut-brain axis (MGBA) has been the subject of much research over the past decade, offering an exciting new paradigm for the treatment of psychiatric disorders. In this review, the MGBA is extended to include skeletal muscle and the potential role of an expanded "muscle-gut-brain axis" (MuGBA) in conditions such as anxiety and depression is discussed. There is evidence, from both preclinical and human studies, of bidirectional links between the gut microbiome and skeletal muscle function and structure. The therapeutic role of exercise in reducing depressive and anxiety symptoms is widely recognised, and the potential role of the gut microbiota-skeletal muscle link is discussed within this context. Potential pathways of communication involved in the MuGBA including the tryptophan-kynurenine pathway, intestinal permeability, immune modulation, and bacterial metabolites such as short-chain-fatty-acids are explored.

Use of new technologies for the promotion of physical activity in patients with mental illness: A systematic review

BACKGROUND

Physical exercise is an underutilized tool for the management of mental disorders. New technologies have made a breakthrough in health care, and one of its possible applications (apps) could be that of customizing exercise programs for special populations, such as patients with mental disorders. However, the app of the so-called e-health to mental health care is still limited.

AIM

To know the efficacy of apps to promote physical activity in patients with mental disorders.

METHODS

We conducted a systematic review of the PubMed and Embase databases with the aim of exploring the use of new technologies for the enhancement of physical exercise in patients with a psychiatric illness. Following the selection process, 10 articles were included in the review.

RESULTS

The most commonly used devices in this type of intervention are wearable devices and web platforms. Good results in terms of effectiveness and acceptability were obtained in most of the studies.

CONCLUSION

Our findings suggest that the use of new technologies in mental health represents a feasible strategy with great potential in clinical practice.

The 50 most-cited review papers on physical activity and depression: A bibliometric analysis

A growing body of literature has demonstrated the preventive role of physical activity in depression, and relevant research is rapidly on the rise. The aim of this study was to conduct a bibliometric analysis of the 50 most-cited review papers on physical activity and depression, thus identifying important research topics and future research directions.

METHODS

The 50 most-cited review articles were identified and extracted from the Web of Science Core Collection database (on 31^st October 2022), and a bibliometric citation analysis was performed using the Microsoft Excel and VOSviewer software (Version 1.6.18). Information on the country, authors of publications, publishing journals, citations (i.e., total or annual), keywords, and other meaningful data was analysed comprehensively.

RESULTS

The 50 most-cited review articles received, on average, 247.5 citations per article. Most review articles were from England, with contributions from some highly cited researchers and research teams. Western countries/regions, such as England, Australia, and the USA were the most influential in publishing review articles on physical activity and depression. The Journal of Affective Disorders and Cochrane Database of Systematic Reviews were the journals that published the most highly cited review articles on physical activity and depression. Important research topics on the literature on physical activity and depression focused on (1) different types of physical activity and depression; (2) intervention studies related to physical activity and depression; (3) fitness and physical activity levels in people with depression; (4) methodological analyses in physical activity and depression studies; and (5) the impact of physical activity on depression in different populations.

CONCLUSION

This study reveals that review studies on physical activity and depression have great potential to develop further knowledge. This study also highlights some future research directions, which can serve to effectively advance the knowledge base.

The body keeps the score: The neurobiological profile of traumatized adolescents

Trauma-related disorders are debilitating psychiatric conditions that affect people who have directly or indirectly witnessed adversities. Experiencing multiple types of traumas appears to be common during childhood, and even more so during adolescence. Dramatic brain/body transformations occurring during adolescence may provide a highly responsive substrate to external stimuli and lead to trauma-related vulnerability conditions, such as internalizing (anxiety, depression, anhedonia, withdrawal) and externalizing (aggression, delinquency, conduct disorders) problems. Analyzing relations among neuronal, endocrine, immune, and biochemical signatures of trauma and internalizing and externalizing behaviors, including the role of personality traits in shaping these conducts, this review highlights that the marked effects of traumatic experience on the brain/body involve changes at nearly every level of analysis, from brain structure, function and connectivity to endocrine and immune systems, from gene expression (including in the gut) to the development of personality.

Ketamine Regulates the Autophagy Flux and Polarization of Microglia through the HMGB1-RAGE Axis and Exerts Antidepressant Effects in Mice

Depression is a leading cause of disability worldwide. Here, we explored the role of the HMGB1-RAGE pathway in lipopolysaccharide (LPS)-induced depression-like behavior and microglial autophagy flux, neuroinflammation, and polarization in a mouse model. Male C57BL/6 mice were infused with LPS in the abdominal cavity to induce a depression model. They then underwent testing to assess behavior and cognition. Real-time fluorescent quantitative polymerase chain reaction was used to detect the expression of the M1/M2 microglia polarization markers, HMGB1, and RAGE. Microglial activation and phenotypic transformation in the hippocampus were identified. mRFP-GFP-LC3 and Western blotting were used to detect autophagy flux in each treatment group. Finally, an LPS-induced BV2 cell model was developed to verify the involvement of the HMGB1-RAGE pathway, autophagy flux, and polarization. Ketamine improved LPS-induced depression-like behavior, inhibited the LPS-induced upregulation of HMGB1 and RAGE and the nuclear translocation of HMGB1. Moreover, ketamine reversed the blocked autophagy flux of microglia caused by LPS and regulated microglial autophagy flux through the HMGB1-RAGE pathway and microglial polarization. These results suggest that ketamine may reduce HMGB1 and RAGE accumulation in patients with depression, thereby providing a new therapeutic target for preventing and treating this disease.

Effect of Voluntary Wheel-Running Exercise on the Endocrine and Inflammatory Response to Social Stress: Conditioned Rewarding Effects of Cocaine

The present paper evaluates the effect of physical activity on the increase of the conditioned rewarding effects of cocaine induced by intermittent social stress and on the neuroinflammatory response that contributes to the enhancement of drug response. For that purpose, three studies were designed in which social stress was induced in different samples of mice through a social-defeat protocol; the mice underwent an increase of physical activity by different modalities of voluntary wheel running (continuous and intermittent access). The results showed that continuous access to running wheels prior to stress enhanced the establishment of cocaine place preference, whereas an intermittent access exerted a protective effect. Wheel running contingent to cocaine administration prevented the development of conditioned preference, and if applied during the extinction of drug memories, it exerted a dual effect depending on the stress background of the animal. Our biological analysis revealed that increased sensitivity to cocaine may be related to the fact that wheel running promotes inflammation though the increase of IL-6 and BDNF levels. Together, these results highlight that physical exercise deeply impacts the organism’s response to stress and cocaine, and these effects should be taken into consideration in the design of a physical intervention.

Immunophenotypic Analysis of T Lymphocytes and Cytokine Production in Elderly Practicing Physical Activities and Its Relationship with Quality of Life and Depression

Aging is a complex process often associated with a chronic inflammatory profile that alters several biological functions, including the immune system and cognitive and physical capacity. The practice of physical activity is increasingly gaining popularity as a method of preventing infections, depression, and other disorders that affect the quality of life of the elderly. Thus, this work analyzes the profile of cytokines and molecular markers expressed in immune cells of elderly people who practice physical activities or not, evaluating their impacts on the immune system and quality of life. For this, 48 individuals were recruited, and peripheral blood samples were collected for hemogram analysis, cytokine determination, and immunophenotyping. Elderly people were separated into two groups: practitioners with low-intensity physical activity and non-practitioners. Quality of life was assessed using the Whoqol-Old instrument, and depression was assessed using the Beck II Depression Inventory. When comparing the scores of the Whoqol-Old and Beck questionnaires, we observed a significant negative correlation between these two factors. The perception of a higher quality of life was present in the elderly who exercised and was related to greater autonomy and sensory abilities, whereas the presence of depression was lower. In the hemogram, we observed higher basophil and segmented counts in the sedentary elderly, whereas lymphocytes and monocytes had lower counts. Elderly practitioners of physical activities had higher levels of IFN-γ, IL-4, and IL-10; increased expression of CD69, PD1, and TIM-3 in CD4+ T lymphocytes and increased CD14+CD80+ and CD14+CD86+ monocytes. Elderly people with an increased perception of quality of life had higher levels of IFN-γ, higher expression of CD14+CD80+CD86+, and decreased levels of TRAIL. An increase in TRAIL was observed in individuals with depression, in addition to an increased expression of CD14+CD86+. These results show a clear correlation between the quality of life, level of depression, physical activity, and immune system function. Although some cytokines with a typical proinflammatory profile (IFN-γ) were observed, the results point to a protective state with benefits reflected in the general well-being of the elderly who exercise.

Pre-Exposure to Environmental Enrichment Protects against Learning and Memory Deficits Caused by Infrasound Exposure

With the development of industrialization in recent years, infrasound has become an important component of public noise. To date, diverse studies have revealed the negative effects of infrasound on the central nervous system (CNS), especially the learning and memory ability. It is widely reported that environmental enrichment (EE) ameliorates the learning and memory deficits in different models of brain injury. Therefore, the present study was designed to determine the possible benefits of pre-exposure to EE in preventing functional deficits following infrasound exposure and their related mechanism. Adult male rats were given enriched or standard housing for 30 days. Following enrichment, the rats were exposed to 16 Hz, 130 dB infrasound for 14 days, and then their learning and memory ability was assessed. Changes to neuroinflammation, apoptosis, and oxidative stress in the hippocampus were also detected. Our results showed that the infrasound-induced deficit in learning and memory was attenuated significantly in EE pre-exposed rats. Pre-exposure to EE could induce a decrease in proinflammatory cytokines and increased anti-inflammatory cytokines and antioxidant properties in the hippocampus. Moreover, pre-exposure to EE also exerted antiapoptosis functions by upregulating the B-cell lymphoma/leukemia-2 (Bcl-2) level and downregulating the P53 level in the hippocampus. In conclusion, the results of the present study suggested that EE is neuroprotective when applied before infrasound exposure, resulting in an improved learning and memory ability by enhancing antioxidant, anti-inflammatory, and antiapoptosis capacities.

Exercise to spot the differences: a framework for the effect of exercise on hippocampal pattern separation in humans

Exercise has a beneficial effect on mental health and cognitive functioning, but the exact underlying mechanisms remain largely unknown. In this review, we focus on the effect of exercise on hippocampal pattern separation, which is a key component of episodic memory. Research has associated exercise with improvements in pattern separation. We propose an integrated framework mechanistically explaining this relationship. The framework is divided into three pathways, describing the pro-neuroplastic, anti-inflammatory and hormonal effects of exercise. The pathways are heavily intertwined and may result in functional and structural changes in the hippocampus. These changes can ultimately affect pattern separation through direct and indirect connections. The proposed framework might guide future research on the effect of exercise on pattern separation in the hippocampus.

Inflammation mediates depression and generalized anxiety symptoms predicting executive function impairment after 18 years

INTRODUCTION

Scar theories propose that elevated depression and anxiety can predispose people to future decreased executive function (EF) via heightened inflammation across decades. However, more longitudinal (versus cross-sectional) research on this topic is needed.

OBJECTIVE

We thus investigated if increased major depressive disorder (MDD), generalized anxiety disorder (GAD), and panic disorder (PD) severity predicted EF decrement 18 years later via heightened inflammation.

METHOD

Community-dwelling adults participated in this study. Time 1 (T1) MDD, GAD, and PD severity (Composite International Diagnostic Interview-Short Form), T2 inflammation (interleukin-6, C-reactive protein, and fibrinogen blood levels concentration), and T2 and T3 EF (Brief Test of Adult Cognition by Telephone) were measured. The waves of assessment were spaced approximately 9 years apart. Structural equation modeling was conducted.

RESULTS

Higher T1 MDD and GAD (but not PD) severity forecasted elevated T2 inflammation (Cohen's d = 0.116-0.758). Greater T2 inflammation level predicted lower T3 EF following 9 years (d = -0.782--0.636). The T1 MDD-T3 EF and T1 GAD-T3 EF negative associations were mediated by T2 inflammation, and explained 38% and 19% of the relations, respectively. Direct effects of higher T1 GAD and MDD predicting lower T3 EF were also observed (d = -0.585--0.560). Significant effects remained after controlling for socio-demographic, lifestyle, medication use, various illness variables across time, and T2 EF.

CONCLUSIONS

Inflammation may be a mechanism explaining the T1 MDD-T3 EF and T1 GAD-T3 EF relations. Treatments that target inflammation, worry, and/or depression may prevent future EF decline.

Late Life Depression: The Essentials and the Essential Distinctions

Late life depression (LLD), a familiar syndrome, is not differentiated in the DSM-5. LLD can resemble depressive syndromes in younger adults but it differs in demographic characteristics, phenomenology, prognosis, treatment, suicide risk, relationship to other disorders, and etiology. Older depressed adults often present with fewer major depressive symptoms, less emphasis on mood disturbance, greater preoccupation with somatic or psychotic symptoms, and misleading cognitive deficits. LLD's relationships with medical and neurocognitive symptoms and with inflammatory and immune factors are complex. Formal screening tools and biopsychosocial assessment informs diagnosis and treatment. Evidence supports the effectiveness of lifestyle interventions, several psychotherapies, and a variety of somatic treatment approaches. Comorbid medical disorders must be taken into account when planning treatment. In this article, the authors describe the characteristics of LLD, present an approach to assessment and management, and recommend that future DSM editions include a new specifier to differentiate LLD from other depressive syndromes.

Common and distinct characteristics associated with self-reported functional status in older patients with cancer receiving chemotherapy

PURPOSE

To evaluate for inter-individual differences in two subjective measures of functional status in older patients (n = 112), as well as to determine which demographic, clinical, and symptom characteristics, and levels of cognitive function, were associated with initial levels and with the trajectory of the two measures.

METHODS

Functional status was assessed using self-report measures of physical function (PF) and role function (RF) from the European Organization for Research and Treatment of Cancer Core Quality-of-Life Questionnaire at the initiation of chemotherapy and at 1, 3, 6, 9, and 12 months after its initiation. Hierarchical linear modeling was used to assess inter-individual differences in and characteristics associated with initial levels and changes in PF and RF.

RESULTS

Characteristics associated with decreases in PF at the initiation of chemotherapy were higher numbers of comorbidities and higher depression, pain, and dyspnea scores. For initial levels of poorer RF, lower Karnofsky Performance Status scores and higher pain and fatigue scores were the associated characteristics. Characteristic associated with worse trajectories of PF was not having had surgery. For RF, worse trajectories were associated with lower cognitive function and higher RF at enrollment. Characteristic associated with both lower initial levels and improved trajectories of PF was having lower performance status at enrollment.

CONCLUSIONS

Older patients undergoing chemotherapy experience reduced functional performance. Characteristics associated with decrements in PF and RF need to be assessed and interventions implemented to maintain and increase functional status in older oncology patients.

FBXO10 prevents chronic unpredictable stress-induced behavioral despair and cognitive impairment through promoting RAGE degradation

Aims

Depression is one of the leading causes of disability worldwide. The receptor for advanced glycosylation end products (RAGE) is closely related to chronic stress and is a target of F‐box protein O10 (FBXO10) which promotes the degradation of RAGE by ubiquitination. Here, we explored the role of FBXO10 and RAGE in chronic unpredictable stress (CUS)‐induced behavioral despair, cognitive impairment, neuroinflammation, and the polarization microglia.

Methods

Male C57BL/6 mice with or without infusion of viral in the medial prefrontal cortex (PFC) were subjected to CUS. Then the mice were exposed to forced swim test, sucrose consumption test, novelty‐suppressed feeding test, and temporal object recognition task to assess the behavioral despair and cognitive impairment. Inflammatory cytokines and the neurotrophic factor brain‐derived neurotrophic factor (BDNF) levels in PFC were assessed by enzyme‐linked immunosorbent assay. Immunofluorescence and immunohistochemistry staining were performed to observe the activation and phenotypic transformation of microglia in PFC. LPS‐induced cell model was constructed to explore the effect of FBXO10/RAGE axis in the polarization of microglia in vitro.

Results

FBXO10 promoted RAGE degradation by ubiquitination in BV2 cells. FBXO10 protein levels were reduced whereas RAGE protein levels were enhanced in CUS mice. FBXO10 overexpression or RAGE knockdown inhibited proinflammatory cytokine release, promoted BDNF expression, mitigated the depressive‐like and cognitive impairment behaviors, and affected the polarization of microglia induced by CUS exposure. FBXO10/RAGE axis promoted the polarization of microglia from the M1 to the M2 phenotype in vitro. Moreover, p38 MAPK and NF‐κΒ were identified to be the downstream effect factors for FBXO10/RAGE axis.

Conclusions

FBXO10 administration prevents CUS‐induced behavioral despair, cognitive impairment, neuroinflammation, and the polarization of microglia through decreasing the accumulation of RAGE, p38 MAPK, and NF‐κΒ, suggesting potential therapeutic strategies for the prevention and treatment of depression.

Reproducible induction of depressive-like behavior in C57BL/6J mice exposed to chronic social defeat stress with a modified sensory contact protocol

AIMS

C57BL/6J mice are well-known to exhibit resilience to chronic social defeat stress (CSDS) for induction of depressive-like behavior. Establishment of protocols for reproducible induction of depressive-like behavior in C57BL/6J mice would be useful to elucidate the underlying molecular mechanisms using target gene-knock-in and -out mice whose background is generally C57BL/6J. Here, we developed a modified CSDS protocol for reproducible induction of depressive-like behavior in C57BL/6J mice, and compared the profile of their gut microbiota with that with the standard CSDS protocol.

MAIN METHODS

To prevent acclimation of defeated C57BL/6J mice to aggressive ICR mice, the sensory contact following a daily 10 min-defeat episode was performed by housing an individual defeated mouse in a cage set next to a cage for the aggressor one.

KEY FINDINGS

The number of attacks by ICR mice on C57BL/6J ones was significantly increased with the modified CSDS protocol, and the susceptible mice exhibited greater hippocampal inflammation and an increased immobility time in the forced swim test, compared in the case of the standard CSDS protocol, and the reproducibility was confirmed in another set of experiments. Both the standard and modified CSDS protocols changed the diversity and relative composition of gut microbiota in the susceptible mice, but there was no apparent difference in them between the standard and modified CSDS-susceptible mice.

SIGNIFICANCE

We established a CSDS protocol for reproducible induction of depressive-like behavior in C57BL/6J mice, and the features of the gut microbiota were similar in the susceptible mice with and without the depressive-like behavior.

P2X7 Receptor as a Potential Target for Major Depressive Disorder

Major depressive disorder (MDD) is a common mental disorder. Although the genetic, biochemical, and psychological factors have been related to the development of MDD, it is generally believed that a series of pathological changes in the brain caused by chronic stress is the main cause of MDD. However, the specific mechanisms underlying chronic stress-induced MDD are largely undermined. Recent investigations have found that increased pro-inflammatory cytokines and changes in the inflammatory pathway in the microglia cells in the brain are the potential pathophysiological mechanism of MDD. P2X7 receptor (P2X7R) and its mediated signaling pathway play a key role in microglia activation. The present review aimed to present and discuss the accumulating data on the role of P2X7R in MDD. Firstly, we summarized the research progress in the correlation between P2X7R and MDD. Subsequently, we presented the P2X7R mediated microglia activation in MDD and the role of P2X7R in increased blood-brain barrier (BBB) permeability caused by chronic stress. Lastly, we also discussed the potential mechanism underlying-P2X7R expression changes after chronic stress. In conclusion, P2X7R is a key molecule regulating the activation of microglia. Chronic stress activates microglia in the hippocampus by secreting interleukin- 1β (IL-1β) and other inflammatory cytokines, and increasing the BBB permeability, thus promoting the occurrence and development of MDD, which indicated that P2X7R might be a promising therapeutic target for MDD.

Delineation of an insula-BNST circuit engaged by struggling behavior that regulates avoidance in mice

Active responses to stressors involve motor planning, execution, and feedback. Here we identify an insular cortex to BNST (insula→BNST) circuit recruited during restraint stress-induced active struggling that modulates affective behavior. We demonstrate that activity in this circuit tightly follows struggling behavioral events and that the size of the fluorescent sensor transient reports the duration of the struggle event, an effect that fades with repeated exposure to the homotypic stressor. Struggle events are associated with enhanced glutamatergic- and decreased GABAergic signaling in the insular cortex, indicating the involvement of a larger circuit. We delineate the afferent network for this pathway, identifying substantial input from motor- and premotor cortex, somatosensory cortex, and the amygdala. To begin to dissect these incoming signals, we examine the motor cortex input, and show that the cells projecting from motor regions to insular cortex are engaged shortly before struggle event onset. This study thus demonstrates a role for the insula→BNST pathway in monitoring struggling activity and regulating affective behavior.

TNF signaling via TNF receptors does not mediate the effects of short-term exercise on cognition, anxiety and depressive-like behaviors in middle-aged mice

BACKGROUND

We recently reported that tumor necrosis factor (TNF) signaling via the TNFR1 and TNFR2 receptors mediates the effects of long-term exercise on locomotion, cognition and anxiety, but not depressive-like behavior. We now investigated whether the TNF signaling via its receptors also mediates the effects of short-term exercise on cognition, anxiety and depressive-like behaviors.

METHODS

Thirteen-month-old C57BL/6 (WT), TNF^-/-, TNFR1^-/-, and TNFR2^-/- mice were provided with 4 weeks of voluntary wheel running followed by behavioral testing using an established behavioral battery. Each genotype had a respective non-exercise control.

RESULTS

There was no interaction between genotype and exercise in any of the tests but the main effect of genotype, and not exercise, were found to be significant in the open field (OF), forced-swim test (FST) and Barnes maze (BM). In the OF, the control and exercise TNFR2^-/- mice spent significantly less time in the inner zone than mice in the control and exercise WT and TNF^-/- cohorts. In the FST, control and exercise WT mice showed significantly higher immobility time than their control and exercise TNF^-/-, TNFR1^-/- and TNFR2^-/- cohorts. In the BM, the latency to escape over 4 days of training was significantly higher in all KO groups compared to WT, irrespective of exercise. Also, the latency to escape to the original location during the probe trial was higher for control and exercise WT compared to corresponding TNFR1^-/- mice. In contrast, the latency to escape to the new location was lower for control and exercise WT compared to control and exercise TNFR1^-/- and TNFR2^-/- mice. The latency to escape to the new location in exercise groups was longer compared to control within all genotypes.

CONCLUSION

While TNF signaling via the TNF receptors mediates cognition, anxiety and depressive-like behaviors independently, it does not mediate the effects of short-term exercise on these behaviors in middle-aged mice.

Analysis of cytokine levels, T regulatory cells and serotonin content in patients with depression

Alterations in peripheral serotonin concentrations and an imbalanced immune system have been reported in patients with depression. Cytokines and T regulatory (Treg) cells may play an important role in the development of depression. This study investigates the levels of cytokines and Treg cells, as well as the concentration of serotonin (5-HT) in the blood of 89 patients suffering from depression and 89 healthy participants between two acquisitions. We investigated the state of health before (T1) and after (T2) psychological and pharmacological therapy. Both cytokine (IL-6, IL-10, TNF-α, and INF-γ) and 5-HT levels in the blood were measured by enzyme-linked immunosorbent assays. The levels of CD4⁺ CD25⁺ Treg cells were determined by flow cytometric analysis. Patients with depression showed significantly higher serum levels of IL-6 and INF-γ, no altered serum levels of IL-10 and TNF-α, and decreased platelet and serum 5-HT levels compared with healthy participants at the first acquisition. In addition, the symptoms of depression and anxiety, the TNF-α level, and the amount of CD4⁺ CD25⁺ cells in the blood were decreased from the first to the second acquisition. Further, a correlation between IL-6 and platelet 5-HT has been observed in patients. An imbalance of the immune system in patients with depression and an association of the serotonergic system and cytokines were observed. These results indicate that the development of depression might be related to several interacting proteins, including cytokines and 5-HT, and the treatment affects imbalances of these factors.

Depression and worry symptoms predict future executive functioning impairment via inflammation

BACKGROUND

Scar models posit that heightened anxiety and depression can increase the risk for subsequent reduced executive function (EF) through increased inflammation across months. However, the majority of past research on this subject used cross-sectional designs. We therefore examined if elevated generalized anxiety disorder (GAD), major depressive disorder (MDD), and panic disorder (PD) symptoms forecasted lower EF after 20 months through heightened inflammation.

METHODS

Community-dwelling adults partook in this study (n = 614; MAGE = 51.80 years, 50% females). Time 1 (T1) symptom severity (Composite International Diagnostic Interview - Short Form), T2 (2 months after T1) inflammation serum levels (C-reactive protein, fibrinogen, interleukin-6), and T3 (20 months after T1) EF (Brief Test of Adult Cognition by Telephone) were assessed. Structural equation mediation modeling was performed.

RESULTS

Greater T1 MDD and GAD (but not PD) severity predicted increased T2 inflammation (Cohen's d = 0.21-1.92). Moreover, heightened T2 inflammation forecasted lower T3 EF (d = -1.98 to -1.87). T2 inflammation explained 25-32% of the negative relations between T1 MDD or GAD and T3 EF. T1 GAD severity predicting T3 EF via T2 inflammation path was stronger among younger (v. older) adults. Direct effects of T1 MDD, GAD, and PD forecasting decreased T3 EF were found (d = -2.02 to -1.92). Results remained when controlling for socio-demographic, physical health, and lifestyle factors.

CONCLUSIONS

Inflammation can function as a mechanism of the T1 MDD or GAD-T3 EF associations. Interventions that successfully treat depression, anxiety, and inflammation-linked disorders may avert EF decrements.

The mediating and interacting role of physical activity and sedentary behavior between diabetes and depression in people with obesity in United States

AIMS

Sufficient physical activity (PA) and less sedentary behavior (SB) have antidepressant effects, however the amount of PA varies according to weight status in adults with diabetes. Given that depression is a common complication of diabetes, we aimed to quantify to what extent the effects of diabetes on the risk of depression were explained by SB or insufficient PA in adults with and without obesity.

METHODS

Data were collected from the 2007-2016 National Health and Nutrition Examination Survey (NHANES), which included 22,304 participants aged 20 years or older. The mediation and interaction were evaluated by the four-way effect decomposition method.

RESULTS

In individuals suffering from obesity, diabetes, SB, and insufficient moderate and vigorous intensity recreational activity were associated with an increased risk of depression. The increased relative risk of diabetes on depression could be decomposed into a reference interaction (96.78%), a mediated interaction (5.07%), and a pure indirect effect (2.48%), with insufficient moderate-intensity recreational activity as a potential mediator. SB attributed a proportion of 89.21% for the controlled direct effect and 3.64% for pure indirect effect.

CONCLUSION

Adults with obesity and diabetes are encouraged to increase moderate-intensity recreational activity and reduce SB, which can greatly prevent the occurrence of depression.

The Effects and Mechanisms of Exercise on the Treatment of Depression

Background: It is necessary to seek alternative therapies for depression, because side effects of medications lead to poor adherence and some patients do not achieve a clinical treatment effect. Recently the role of exercise as a low-cost and easy-to-use treatment for depression has gained attention with a number of studies showing that exercise is effective at reducing depressive symptoms and improving body functions such as cardiorespiratory system and cognitive function. Because of the heterogeneity of exercise therapy programs, there is no standardized and unified program. Few studies have summarized the specific properties of exercise programs (type, intensity, duration, and frequency) and clinical prescriptions for exercise are not mentioned in most articles. Aims: This study aimed to investigate the feasibility and efficacy of exercise therapy for patients with depression, in order to appraise the evidence and outline accepted guidelines to direct individualized treatment plans for patients with depression based on their individual situations. Methods: A systematic review of English language literature including papers published from 2010 to present in PubMed was performed. Given the feasibility of prescribing exercise therapy for patients with depression, nearly 3 years of clinical studies on the treatments of depressive symptoms with exercise were first reviewed, comparing the exercise programs utilized. Conclusions: Exercise has therapeutic effects on depression in all age groups (mostly 18-65 years old), as a single therapy, an adjuvant therapy, or a combination therapy, and the benefits of exercise therapy are comparable to traditional treatments for depression. Moderate intensity exercise is enough to reduce depressive symptoms, but higher-dose exercise is better for overall functioning. Exercise therapy has become more widely used because of its benefits to the cardiovascular system, emotional state, and systemic functions. Recommendations: Aerobic exercise/mind-body exercise (3-5 sessions per week with moderate intensity lasting for 4-16 weeks) is recommended. Individualized protocols in the form of group exercise with supervision are effective at increasing adherence to treatment.

Significance of gastrointestinal tract in the therapeutic mechanisms of exercise in depression: Synchronism between brain and intestine through GBA

Researchers have made considerable progress in elucidating psychological and exercise correlates of major depressive disorder (MDD). However, as the largest immune organ, far less is known about the role of gastrointestinal (GI) tract in the therapeutic mechanisms of exercise in MDD. In addition to the sites of the digestive tract that absorb nutrients, the GI tract also serves as a protective barrier against organisms. Inflammation and other consequences caused by disrupted GI barrier integrity are considered to be one of the mechanisms of depression, and the gut-brain axis (GBA) plays a critical role in this process. In this work, we observed the depression-like behaviors, intestinal barrier, central and peripheral inflammation, and related neurotransmitters through exercise intervention in the chronic unpredictable mild stress (CUMS) model, aiming to clarify the mechanisms of exercise to improve depression through GBA. Our results revealed that, following increased expressions of pro-inflammatory factors in intestine of CUMS mice, the levels of pro-inflammatory factors were all significantly raised in serum and brain simultaneously. Further, glial cells were activated in visceral nervous system and its related brain regions at the same time, accompanied by lower expression of occludin in CUMS mice. Importantly, our findings provide the first evidence that eight weeks of running exercise effectively inhibited neuro-immune interactions along gut-brain-axis and contributed obvious improvement of intestinal epithelial barrier (IEB). Finally, multivariate analysis putatively highlighted the role of exercise-induced IEB protection on depression treatment. We hope that our findings could warrant further study of therapeutic mechanisms of exercise in depression, specifically in disentangling the roles of intestinal function and IEB protection, and for developing more targeted clinical depression interventions.

Exercise-induced immune system response: Anti-inflammatory status on peripheral and central organs

A wide array of molecular pathways has been investigated during the past decade in order to understand the mechanisms by which the practice of physical exercise promotes neuroprotection and reduces the risk of developing communicable and non-communicable chronic diseases. While a single session of physical exercise may represent a challenge for cell homeostasis, repeated physical exercise sessions will improve immunosurveillance and immunocompetence. Additionally, immune cells from the central nervous system will acquire an anti-inflammatory phenotype, protecting central functions from age-induced cognitive decline. This review highlights the exercise-induced anti-inflammatory effect on the prevention or treatment of common chronic clinical and experimental settings. It also suggests the use of pterins in biological fluids as sensitive biomarkers to follow the anti-inflammatory effect of physical exercise.

Enhancement of Hippocampal Plasticity by Physical Exercise as a Polypill for Stress and Depression: A Review

Generation of newborn neurons that form functional synaptic connections in the dentate gyrus of adult mammals, known as adult hippocampal neurogenesis, has been suggested to play critical roles in regulating mood, as well as certain forms of hippocampus-dependent learning and memory. Environmental stress suppresses structural plasticity including adult neurogenesis and dendritic remodeling in the hippocampus, whereas physical exercise exerts opposite effects. Here, we review recent discoveries on the potential mechanisms concerning how physical exercise mitigates the stressrelated depressive disorders, with a focus on the perspective of modulation on hippocampal neurogenesis, dendritic remodeling and synaptic plasticity. Unmasking such mechanisms may help devise new drugs in the future for treating neuropsychiatric disorders involving impaired neural plasticity.

Daily physical activity in patients on chronic haemodialysis and its relation with fatigue and depressive symptoms

OBJECTIVE

Fatigue and depressed mood are considered main impediments to physical activity in haemodialysis (HD) patients. A better understanding of their interrelationships is crucial to develop effective therapies. Moreover, measurement of daily physical activity (DPA) in HD patients is tricky, as it is usually assessed by subjective self-report questionnaires. Therefore, we aimed to objectively measure sponteanous DPA with motion sensors and to explore its relation with fatigue and depressive symptoms.

METHODS

DPA was assessed for seven consecutive days in 37 HD patients based on their daily step count measured with the SenseWear™ Armband. The Fatigue Severity Scale (FSS) and Beck Depression Inventory-II (BDI-II) were administered to evaluate fatigue and depressed mood.

RESULTS

Median DPA was 2424 steps/day, (IQR:892-4545). In 81% of subjects, DPA felt within a sedentary lifestyle classification, as they made < 5.000 steps/day. DPA did not correlate with fatigue (r_s = 0.04, p = 0.832), and did not significantly differ between patients categorized as clinically fatigued (n = 23, FSS ≥ 4) or not (n = 14, FSS < 4) (p = 0.654, d = 0.20). Although low-depressed subjects (n = 19, BDI-II ≤ 13) made on average 1.7 times more steps/day than high-depressed subjects (n = 18, BDI-II > 13) (p = 0.111, d = 0.60), depressive mood did also not correlate significantly with DPA (r_s = - 0.23, p = 0.175).

CONCLUSION

Objective assessment of DPA with motion sensors is feasible in HD patients and allows identifying a sedentary lifestyle. Our results suggest that spontanous DPA is determined by age rather than by fatigue or mood.

Differential impact of stress and environmental enrichment on corticolimbic circuits

Stress exposure can produce profound changes in physiology and behavior that can impair health and well-being. Of note, stress exposure is linked to anxiety disorders and depression in humans. The widespread impact of these disorders warrants investigation into treatments to mitigate the harmful effects of stress. Pharmacological treatments fail to help many with these disorders, so recent work has focused on non-pharmacological alternatives. One of the most promising of these alternatives is environmental enrichment (EE). In rodents, EE includes social, physical, and cognitive stimulation for the animal, in the form of larger cages, running wheels, and toys. EE successfully reduces the maladaptive effects of various stressors, both as treatment and prophylaxis. While we know that EE can have beneficial effects under stress conditions, the morphological and molecular mechanisms underlying these behavioral effects are still not well understood. EE is known to alter neurogenesis, dendrite development, and expression of neurotrophic growth factors, effects that vary by type of enrichment, age, and sex. To add to this complexity, EE has differential effects in different brain regions. Understanding how EE exerts its protective effects on morphological and molecular levels could hold the key to developing more targeted pharmacological treatments. In this review, we summarize the literature on the morphological and molecular consequences of EE and stress in key emotional regulatory pathways in the brain, the hippocampus, prefrontal cortex, and amygdala. The similarities and differences among these regions provide some insight into stress-EE interaction that may be exploited in future efforts toward prevention of, and intervention in, stress-related diseases.

Human needs in COVID-19 isolation

To reduce the spread of COVID-19, the World Health Organization and the majority of governments have recommended that the entire human population should ‘stay-at-home’. A significant proportion of the population live alone or are vulnerable to mental health problems yet, in the vast majority of cases, individuals in social isolation have no access to mental healthcare. The only resource is people themselves using self-help, self-medication and self-care. During prolonged COVID-19 isolation, an in-built system of homeostasis can help rebalance activity, thought and feeling. Increased physical activity enables a reset of physical and mental well-being. During periods of lockdown, it is recommended that exercise should be as vigorously promoted as social distancing itself.

Impacts of exercise intervention on various diseases in rats

BACKGROUND

Exercise is considered as an important intervention for treatment and prevention of several diseases, such as osteoarthritis, obesity, hypertension, and Alzheimer's disease. This review summarizes decadal exercise intervention studies with various rat models across 6 major systems to provide a better understanding of the mechanisms behind the effects that exercise brought.

METHODS

PubMed was utilized as the data source. To collect research articles, we used the following terms to create the search: (exercise [Title] OR physical activity [Title] OR training [Title]) AND (rats [Title/Abstract] OR rat [Title/Abstract] OR rattus [Title/Abstract]). To best cover targeted studies, publication dates were limited to "within 11 years." The exercise intervention methods used for different diseases were sorted according to the mode, frequency, and intensity of exercise.

RESULTS

The collected articles were categorized into studies related to 6 systems or disease types: motor system (17 articles), metabolic system (110 articles), cardiocerebral vascular system (171 articles), nervous system (71 articles), urinary system (2 articles), and cancer (21 articles). Our review found that, for different diseases, exercise intervention mostly had a positive effect. However, the most powerful effect was achieved by using a specific mode of exercise that addressed the characteristics of the disease.

CONCLUSION

As a model animal, rats not only provide a convenient resource for studying human diseases but also provide the possibility for exploring the molecular mechanisms of exercise intervention on diseases. This review also aims to provide exercise intervention frameworks and optimal exercise dose recommendations for further human exercise intervention research.

Vitamin D status was not associated with anxiety, depression, or health-related quality of life in Middle Eastern and African-born immigrants in Sweden

Active vitamin D is a neurosteroid that may modulate brain function. Associations between vitamin D deficiency and depression and anxiety have been demonstrated. We hypothesized that there was an association between anxiety, depression, and health-related quality of life (HRQOL) and vitamin D status. To test this hypothesis, we examined the association between anxiety, depression, and HRQOL and 25-hydroxyvitamin D (25[OH]D) concentrations in the Middle Eastern and African-born immigrant population. All immigrants aged 25-65 years, born in 9 African or Middle Eastern countries, and living in 3 districts in Umeå (n = 1306) were invited, with 195 English- or Swedish-speaking immigrants (104 men and 91 women) participated. Anxiety and depression were measured using the Hospital Anxiety and Depression scale. HRQOL was measured using EuroQoL-5 Dimension 3 Level Questionnaire and EuroQoL Visual Analogue Scale. Serum 25(OH)D was measured using liquid chromatography-tandem mass spectrometry. Associations were determined using logistic and linear regression. Analyses were adjusted for sex, age, origin, socioeconomic factors, lifestyle, chronic diseases, and obesity. In total, 71% had 25(OH)D less than 50 nmol/L and 11% had 25(OH)D less than 25 nmol/L. Anxiety, depression, and HRQOL were not associated with 25(OH)D in the immigrant population. Anxiety was common in female immigrants from the Middle East (32.7%); and after adjustment, lower 25(OH)D concentrations were associated with higher risk of anxiety (25[OH]D ≤ 49 nmol/L vs 25[OH]D ≥ 50 nmol/L: odds ratio 23.2 [95% confidence interval 1.97 - 271.9] P = .012) in this subgroup only; however, reverse causality could not be excluded. In conclusion, the study showed no association between depression, anxiety, or HRQOL and vitamin D status in the immigrant population.

Risk and protective factors associated with depressive symptoms in young adults with overweight and obesity

Objective: Approximately one-third of college students are categorized as overweight/obese and elevated weight has been associated with increased risk of depressive symptoms. Less is known about protective factors in this context. This study examined associations between depressive symptoms and health behaviors, as well as body image variables among college students with overweight/obesity, while accounting for contributions of BMI and demographics. Participants: College students (N = 175; M_age = 19.87, SD = 1.93; 70% female; 58% Non-Hispanic Black) with overweight/obesity completed in-person surveys. Methods: Depressive symptoms, exercise and diet engagement, body positivity, and body dissatisfaction were assessed. Data were examined using a hierarchical linear regression. Results: Greater exercise engagement and greater body positivity were significantly associated with lower levels of depressive symptoms. Conclusions: Established links between elevated weight and depression are complex but imperative to understand, as mutable factors that contribute to this relationship may provide novel avenues for intervening.

Total physical activity but not diet quality associated with postnatal depressive symptoms amongst women living in socioeconomically disadvantaged neighborhoods

Lifestyle behaviors such as healthy diet and some forms of physical activity have been linked to lower risk of depressive symptoms in the general population. However, little is known regarding their associations with postnatal depressive symptoms. Given that postnatal women (particularly those living in socioeconomically disadvantaged neighborhoods) are more likely to have poorer diet quality, lower physical activity levels and greater risk of depressive symptoms, this study sought to determine the associations between diet quality, total and domain specific physical activity and depressive symptoms amongst postnatal women from socioeconomically disadvantaged neighborhoods. It was hypothesized that higher diet quality and levels of leisure-time physical activity would be associated with lower depressive symptoms. In 2007-2008, cross-sectional data were collected from 246 women living in socioeconomically disadvantaged neighborhoods in Victoria, Australia. Participants completed self-report measures of diet (using a 17 item dietary questionnaire), domain specific physical activity (International Physical Activity Questionnaire), and depressive symptoms (Centre for Epidemiologic Studies Depression Scale). Linear regression analyses were used to determine the associations between diet quality, physical activity and postnatal depressive symptoms. There was a significant inverse association between total physical activity (B, -0.009; 95% CI, -0.016 to -0.001; P = .023) and postnatal depressive symptoms. No association was found between other domain-specific physical activity (i.e. leisure-time, domestic or transport-related physical activity), or diet quality and postnatal depressive symptoms. Acknowledging the cross-sectional nature of this study, these findings suggest that total physical activity may play a more important role than diet quality in the relationship with postnatal depressive symptoms.

Neurobiological effects of aerobic exercise, with a focus on patients with schizophrenia

Schizophrenia is a severe neuropsychiatric disease that is associated with neurobiological alterations in multiple brain regions and peripheral organs. Negative symptoms and cognitive deficits are present in about half of patients and are difficult to treat, leading to an unfavorable functional outcome. To investigate the impact of aerobic exercise on various neurobiological parameters, we conducted a narrative review. Add-on aerobic exercise was shown to be effective in improving negative and general symptoms, cognition, global functioning, and quality of life in schizophrenia patients. Based on findings in healthy individuals and animal models, this qualitative review gives an overview of different lines of evidence on how aerobic exercise impacts brain structure and function and molecular mechanisms in patients with schizophrenia and how its effects could be related to clinical and functional outcomes. Structural magnetic resonance imaging studies showed a volume increase in the hippocampus and cortical regions in schizophrenia patients and healthy controls after endurance training. However, results are inconsistent and individual risk factors may influence neuroplastic processes. Animal studies indicate that alterations in epigenetic mechanisms and synaptic plasticity are possible underlying mechanisms, but that differentiation of glial cells, angiogenesis, and possibly neurogenesis may also be involved. Clinical and animal studies also revealed effects of aerobic exercise on the hypothalamus-pituitary-adrenal axis, growth factors, and immune-related mechanisms. Some findings indicate effects on neurotransmitters and the endocannabinoid system. Further research is required to clarify how individual risk factors in schizophrenia patients mediate or moderate the neurobiological effects of exercise on brain and cognition. Altogether, aerobic exercise is a promising candidate in the search for pathophysiology-based add-on interventions in schizophrenia.

Blood Pressure Control and Protection of the Aging Brain

Hypertension and dementia are both common disorders whose prevalence increases with age. There are multiple mechanisms by which hypertension affects the brain and alters cognition. These include blood flow dynamics, development of large and small vessel pathology and diverse molecular mechanisms including formation of reactive oxygen species and transcriptional cascades. Blood pressure interacts with Alzheimer disease pathology in numerous and unpredictable ways, affecting both β-amyloid and tau deposition, while also interacting with AD genetic risk factors and other metabolic processes. Treatment of hypertension may prevent cognitive decline and dementia, but methodological issues have limited the ability of randomized clinical trials to show this conclusively. Recent studies have raised hope that hypertension treatment may protect the function and structure of the aging brain from advancing to mild cognitive impairment and dementia.

Physical exercise and body mass index as correlates of major depressive disorder in community-dwelling adults: Results from the PISMA-ep study

BACKGROUND

Major Depressive Disorder (MDD) is one of the most prevalent and disabling mental disorders. Sedentarism and obesity are recognized risk factors for MDD. Physical exercise has shown beneficial effects on mental health and there is an increasing awareness of its potential as a therapeutic and preventive tool for depression. No epidemiological studies have explored the role of physical activity and obesity as potential correlates of MDD in the Spanish population. The aim of this study was to explore whether MDD was associated with two strongly linked variables: physical exercise and body mass index.

METHODS

The PISMA-ep is a cross-sectional community-based study carried out in Andalusia, southern Spain. Main outcome was current prevalence of MDD, measured through face-to-face interviews using the Mini-International Neuropsychiatric Interview (MINI). Independent variables explored were physical exercise and its intensity, Body Mass Index (BMI), BMI categories (underweight, normal weight, overweight and obesity), hip and waist circumferences, general health status measured with the SF12 questionnaire, and sociodemographic factors.

RESULTS

Physical exercise was inversely associated with MDD, acting as a protective factor. Higher intensity of exercise strengthened this association. Four variables were independently associated with MDD in the multivariate association model: female sex, physical exercise, general health status and BMI.

CONCLUSION

MDD was associated with poorer health status, higher BMI and reduced physical activity. Physical exercise should be considered as a potential intervention for the treatment and prevention of MDD in clinical and public health settings.

NPY Receptor 2 Mediates NPY Antidepressant Effect in the mPFC of LPS Rat by Suppressing NLRP3 Signaling Pathway

Accumulated evidences show that neuroinflammation play a pivotal role in the pathogenesis of depression. Neuropeptide Y (NPY) and its receptors have been demonstrated to have anti-inflammative as well as antidepressant effects. In the present study, the ability of NPY to modulate depressive-like behaviors induced by lipopolysaccharides (LPS) in rats and the receptors and signaling mechanisms involved were investigated. Continuous injection LPS (i.p) for 4 days led to development of depressive-like behaviors in rats, accompanied with M1-type microglia activation and increased levels of IL-1β as well as decreased levels of NPY and Y2R expression in the mPFC selectively. Local injection of NPY into the medial prefrontal cortex (mPFC) ameliorated the depression-like behaviors and suppressed the NLRP3 inflammasome signaling pathway. Y2R agonist PYY (3-36) mimicked and Y2R antagonist BIIE0246 abolished the NPY effects in the mPFC. All these results suggest that NPY and Y2R in the mPFC are involved in the pathophysiology of depression and NPY plays an antidepressant role in the mPFC mainly via Y2R, which suppresses the NLRP3 signaling pathway, in LPS-induced depression model rats.

Exercise Your Kynurenines to Fight Depression

Kynurenines, the major degradative products of the essential amino acid tryptophan, may play critical roles in the pathophysiology of depressive disorders. In 2014, Agudelo and colleagues reported that exercise indirectly modulates the metabolism of kynurenines in skeletal muscle, which in turn influences the brain and enhances resilience to depression.