From inflammation to sickness and depression: when the immune system subjugates the brain. Nat Rev Neurosci. 2008;9:46-56. [PMID: 18073775 DOI: 10.1038/nrn2297]

Acute and chronic response of supervised band-elastic resistance exercise in systemic cytokines levels of bipolar disorders and schizophrenia individuals: A pilot study

Despite earlier research demonstrating the immunomodulatory effects of acute and chronic exercise in many medical illnesses, there is a lack of literature evaluating the acute and chronic effects of exercise on the cytokine levels in individuals with bipolar disorder (BD) or schizophrenia (SCH). This study aims to examine the acute effects of resistance exercise on cytokines and the chronic effects of resistance exercise by 10 weeks on cytokine levels, symptoms of disease, and muscular strength in individuals with BD and SCH. The included individuals (N=10) performed a single session of band-elastic resistance exercises (six exercises, 3 sets of 12-15 repetitions, 60 seconds of interval between sets). A sub-sample (N=6) of individuals performed a supervised band-elastic resistance exercise program (2 times a week, for 10 weeks, 6 exercises, 3 sets of 12-15 repetitions, 60 seconds of interval). We verified for acute effects: IL-2 (P=0.0085) and IL-4 (P=0.0253) levels increased, while IL-6 decreased (P=0.0435), and for chronic effects: increased IL-2 and IL-4 levels (significant effect size - Pre vs Post), a decrease in disease symptoms, and an increase in muscular strength. This study adds to what is already known about how resistance exercises affect people with BD and SCH in both short-term (systemic cytokines levels) and long-term (symptoms of disease, muscular strength, and systemic cytokines levels).

Mouse Testing Methods in Psychoneuroimmunology: Measuring Behavioral Responses

The field of psychoneuroimmunology (PNI) aims to uncover the processes and consequences of nervous, immune, and endocrine system relationships. Behavior is a consequence of such interactions and manifests from a complex interweave of factors including immune-to-neural and neural-to-immune communication. Often the signaling molecules involved during a particular episode of neuroimmune activation are not known, but behavioral response provides evidence that bioactives such as neurotransmitters and cytokines are perturbed. Immunobehavioral phenotyping is a first-line approach when examining the neuroimmune system and its reaction to immune stimulation or suppression. Behavioral response is significantly more sensitive than direct measurement of a single specific bioactive and can quickly and efficiently rule in or out relevance of a particular immune challenge or therapeutic to neuroimmunity. Classically, immunobehavioral research was focused on sickness symptoms related to bacterial infection, but neuroimmune activation is now a recognized complication of diseases and disorders ranging from cancer to diabesity to Alzheimer's. Immunobehaviors include lethargy, loss of appetite, and disinterest in social activity/surrounding environment. In addition, neuroimmune activation can diminish physical activity, precipitate feelings of depression and anxiety, and impair cognitive and executive function. Provided is a detailed overview of behavioral tests frequently used to examine neuroimmune activation in mice with a special emphasis on pre-experimental conditions that can confound or prevent successful immunobehavioral experimentation.

The MRL Model: A Valuable Tool in Studies of Autoimmunity-Brain Interactions

The link between systemic autoimmunity, brain pathology, and aberrant behavior is still largely unexplored field of biomedical science. Accumulating evidence points to causal relationships between immune factors, neurodegeneration, and neuropsychiatric manifestations. By documenting autoimmunity-associated neuronal degeneration and cytotoxicity of the cerebrospinal fluid from disease-affected subjects, the murine MRL model has shown high validity in revealing principal pathogenic circuits. In addition, unlike any other autoimmune strain, MRL mice produce antibodies commonly found in patients suffering from lupus and other autoimmune disorders. This review highlights the importance of the MRL model as a useful preparation for understanding the links between the immune system and brain function.

Psychoneuroimmunology of Mood Disorders

Recent research has shed light on the intricate relationship between mood disorders, such as major depressive disorder (MDD) and bipolar disorder (BD), and inflammation. This chapter explores the complex interplay involving immune and metabolic dysfunction in the pathophysiology of these disorders, emphasizing their association with autoimmunity/inflammatory conditions, chronic low-grade systemic inflammation, T cell overactivation, and immunosenescence. This perspective underscores the notion that MDD and BD are not solely brain disorders, highlighting their nature as multi-system conditions.

Association between window ventilation frequency and depressive symptoms among older Chinese adults

OBJECTIVES

Indoor air pollution exposure is harmful to people's physical and mental health, especially in the elderly population. Depressive symptoms are the most common mental health issue among elderly individuals. However, evidence linking the frequency of indoor natural ventilation to depressive symptoms in the elderly population is limited.

METHODS

This study included 7887 individuals 65 years and older from 2017 to 2018 the China Longitudinal Healthy Longevity Survey (CLHLS). The frequency of indoor window ventilation was measured as the self-reported times of ventilation of indoor window per week in each season, and the four seasons' scores were added up to calculate the annual ventilation frequency. Depressive symptoms were measured by the 10-item Center for Epidemiologic Studies Short Depression Scale (CESD). Using three models adjusted for demographic, socio-economic, health status, and environmental factors successively, the correlation between indoor window ventilation frequency and depressive symptoms was verified through logistic regression.

RESULTS

Among the 7887 elderly people included in this study, 1952 (24.7 %) had depressive symptoms. In the fully adjusted model, compared with the lower indoor annual ventilation frequency group, high indoor annual ventilation frequency group was significantly associated with a 33 % (OR: 0.67, 95%CI: 0.51-0.88) lower probability of depressive symptoms. Subgroup analysis and sensitivity analysis yielded similar results.

CONCLUSIONS

High frequency of window ventilation is significantly associated with the lower risk of depressive symptoms in Chinese individuals aged 65 and older. This result provides strong evidence for health intervention and policy formulation.

Pharmaceutical-mediated neuroimmune modulation in psychiatric/psychological adverse events

The therapeutic use of many pharmaceuticals, including small molecules and biological therapies, has been associated with the onset of psychiatric and psychological adverse events (PPAEs), posing substantial concerns to patients' health and safety. These events, which encompass mood (e.g., depression, schizophrenia, suicidal ideation) and cognitive changes (e.g., learning and memory impairment, dementia) often remain undetected until advanced stages of clinical trials or pharmacovigilance, mostly because the mechanisms underlying the onset of PPAEs remain poorly understood. In recent years, the role of neuroimmune modulation (comprising an intricate interplay between various cell types and signaling pathways) in PPAEs has garnered substantial interest. Indeed, understanding these complex interactions would substantially contribute to increase the ability to predict the potential onset of PPAEs during preclinical stages of a new drug's R&D. This review provides a comprehensive summary of the most recent advances in neuroimmune modulation-related mechanisms contributing to the onset of PPAEs and their association with specific pharmaceuticals. Reported data strongly support an association between neuroimmune modulation and the onset of PPAEs. Pharmaceuticals may target specific molecular pathways and pathway elements (e.g., cholinergic and serotonergic systems), which in turn may directly or indirectly impact the inflammatory status and the homeostasis of the brain, regulating inflammation and neuronal function. Also, modulation of the peripheral immune system by pharmaceuticals that do not permeate the blood-brain barrier (e.g., monoclonal antibodies) may alter the neuroimmunomodulatory status of the brain, leading to PPAEs. In summary, this review underscores the diverse pathways through which drugs can influence brain inflammation, shedding light on potential targeted interventions.

The triangular relationship of physical activity, depression, and inflammatory markers: A large cross-sectional analysis with NHANES data

Depression is a major public health problem worldwide and is closely related with systemic inflammatory responses. Additionly, physical activity (PA) is thought to be associated with lower levels of depression and inflammatory markers. This study aimed to elucidate the complex interactions between PA, depression, and inflammatory markers. Based on the National Health and Nutrition Examination Survey (NHANES), various logistic regression were applied to analyze the pairwise correlations among the three. Restrictive cubic splines were constructed to explore the nonlinear relationship between PA and depression. Mediation models were used to identify the mediating role of inflammatory markers. The findings revealed a positive link between depression and inflammatory marker, whereas PA was inversely correlated with both inflammatory marker and depression. Particularly, we noticed the greatest reduction in the risk of depression when the level of PA was between 1200 and 1722 MET-min/week. Besides, we demonstrated that inflammatory markers mediate the potential effects of physical inactivity on depression, ranging from 1.72 % to 6.25 %. In conclusion, PA appear to protect against depression, in which inflammatory markers may play a mediating role. Moreover, we determined the optimal dosage of PA to minimize the likelihood of depression, thereby offering valuable guidance for managing depression.

Exposure to acrylamide and increased risk of depression mediated by inflammation, oxidative stress, and alkaline phosphatase: Evidence from a nationally representative population-based study

BACKGROUND

The health risk associated with acrylamide exposure has emerged as a significant issue of public health, attracting global attention. However, epidemiologic evidence on whether and how daily acrylamide exposure increases depression risk of the general population is unclear.

METHODS

The study included 3991 adults from the National Health and Nutrition Examination Survey. The urinary metabolites of acrylamide (N-Acetyl-S-(2-carbamoylethyl)-L-cysteine [AAMA] and N-Acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine [GAMA]) identified as reliable indicators of acrylamide exposure were examined to determine their relationships with depressive symptoms that were evaluated using the 9-item Patient Health Questionnaire. Besides, the measurements of alkaline phosphatase (ALP) and biomarkers of inflammation (white blood cell [WBC] count) and anti-oxidative stress (albumin [ALB]) were conducted to investigate their mediation roles in above relationships.

RESULT

AAMA, GAMA, and ΣUAAM (AAMA+GAMA) were linearly associated with increased risk of depressive symptoms. Each 2.7-fold increase in AAMA, GAMA, or ΣUAAM was associated with a 30 % (odds ratio: 1.30; 95 % confidence interval: 1.09, 1.55), 47 % (1.47; 1.16, 1.87), or 36 % (1.36; 1.13, 1.63) increment in risk of depressive symptoms, respectively. Increased WBC count (mediated proportion: 4.48-8.00 %), decreased ALB (4.88-7.78 %), and increased ALP (4.93-5.23 %) significantly mediated the associations between acrylamide metabolites and depressive symptoms.

CONCLUSIONS

Acrylamide exposure of the general adult population was related to increased risk of depressive symptoms, which was mediated in part by inflammation, oxidative stress, and increased ALP. Our findings provided pivotal epidemiologic evidence for depression risk increment from exposure to acrylamide.

Neural and immune interactions linking early life stress and anhedonia

Early experiences of stress and adversity are associated with blunted reward sensitivity and altered reward learning. Meanwhile, anhedonia is characterized by impairments in reward processing, including motivation, effort, and pleasure. Early life stress (ELS) and anhedonia share psychological, behavioral, and neurobiological correlates, and the system-level interactions that give rise to anhedonia have yet to be fully appreciated. The proposed framework uses a multilevel, multisystem approach to aid in understanding neural-immune interactions that link ELS and anhedonia. The interactions linking anhedonia and ELS presented here include reduced reward sensitivity, alterations in hypothalamic-pituitary-adrenal (HPA) axis response, elevated inflammatory cytokines or physiological markers of stress, and blunted reward circuitry functioning along the mesocorticolimbic pathway. The clinical implications and areas for future research are also discussed. Ultimately, this research may inform the development of more specific and individualized treatments for anhedonia.

The Pathophysiology and Biomarkers of Delirium

Delirium is a major disturbance in the mental state characterized by fluctuations in arousal, deficits in attention, distorted perception, and disruptions in memory and cognitive processing. Delirium affects approximately 18% to 25% of hospital inpatients, with even higher rates observed during critical illness. To develop therapies to shorten the duration and limit the adverse effects of delirium, it is important to understand the mechanisms underlying its presentation. Neuroimaging modalities such as magnetic resonance imaging (MRI), positron emission tomography, functional MRI, and near-infrared spectroscopy point to global atrophy, white matter changes, and disruptions in cerebral blood flow, oxygenation, metabolism, and connectivity as key correlates of delirium pathogenesis. Electroencephalography demonstrates generalized slowing of normal background activity, with pathologic decreases in variability of oscillatory patterns and disruptions in functional connectivity among specific brain regions. Elevated serum biomarkers of inflammation, including interleukin-6, C-reactive protein, and S100B, suggest a role of dysregulated inflammatory processes and cellular metabolism, particularly in perioperative and sepsis-related delirium. Emerging animal models that can mimic delirium-like clinical states will reveal further insights into delirium pathophysiology. The combination of clinical and basic science methods of exploring delirium shows great promise in elucidating its underlying mechanisms and revealing potential therapeutic targets.

Psychological stressors involved in the pathogenesis of premature ovarian insufficiency and potential intervention measures

Premature ovarian insufficiency (POI) is a common gynecological endocrine disease, which seriously affects women's physical and mental health and fertility, and its incidence is increasing year by year. With the development of social economy and technology, psychological stressors such as anxiety and depression caused by social, life and environmental factors may be one of the risk factors for POI. We used PubMed to search peer-reviewed original English manuscripts published over the last 10 years to identify established and experimental studies on the relationship between various types of stress and decreased ovarian function. Oxidative stress, follicular atresia, and excessive activation of oocytes, caused by Stress-associated factors may be the main causes of ovarian function damage. This article reviews the relationship between psychological stressors and hypoovarian function and the possible early intervention measures in order to provide new ideas for future clinical treatment and intervention.

Depression, stress, and tryptophan metabolism through the kynurenine pathway: treatment strategies from the perspective of Chinese herbal medicine

The pathogenesis of depression is complex, involving abnormalities in tryptophan (TRP) metabolism through the kynurenine pathway (KP). Moreover, depression is closely related to the hypothalamic-pituitary-adrenal (HPA) axis, the gut-brain axis, neuroinflammation, and stress. These factors collectively influence the multidimensional pathological mechanisms of depression. TRP, a fundamental amino acid, serves as a precursor for neuroactive metabolites vital to physiological functions. Central to TRP metabolism is the KP, and the imbalance between neurotoxic and neuroprotective metabolites is closely related to the onset and progression of depression. Therefore, maintaining the balance of KP metabolites is important. In this review, we have investigated the role of the KP in depression and explored the complexity of KP dysregulation and its therapeutic importance. Here, we highlight how a deeper understanding of the KP and its regulation can pave the way for new treatment strategies. Specifically, we have summarized the latest advances in elucidating the key mechanisms of rate-limiting enzyme inhibitors, providing insights into their potential therapeutic efficacy. In addition, we have explored the emerging field of Chinese herbal medicine, discussing its potential to regulate KP metabolites and alleviate depressive symptoms, thereby expanding the treatment options for depression. Our findings emphasize the multifaceted nature of depression and the necessity of interdisciplinary research to fully utilize KP regulation and Chinese herbal medicine as strategies to advance the treatment of depression.

Platelet's plea to Immunologists: Please do not forget me

Platelets are non-nucleated mammalian cells originating from the cytoplasmic expulsion of the megakaryocytes. Megakaryocytes develop during hematopoiesis through megakaryopoiesis, whereas platelets develop from megakaryocytes through thrombopoiesis. Since their first discovery, platelets have been studied as critical cells controlling hemostasis or blood coagulation. However, coagulation and innate immune response are evolutionarily linked processes. Therefore, it has become critical to investigate the immunological functions of platelets to maintain immune homeostasis. Advances in immunology and platelet biology research have explored different critical roles of platelets, including phagocytosis, release of different immune mediators, and controlling functions of different immune cells by direct interaction and immune mediators. The current article discusses platelet's development and their critical role as innate immune cells, which express different pattern recognition receptors (PRRs), recognizing different pathogen or microbe-associated molecular patterns (PAMPs or MAMPs) and death/damage-associated molecular patterns (DAMPs) and their direct interactions with innate and adaptive immune cells to maintain immune homeostasis.

Hippocampal neuroinflammation induced by lipopolysaccharide causes sex-specific disruptions in action selection, food approach memories, and neuronal activation

Hippocampal neuroinflammation is present in multiple diseases and disorders that impact motivated behaviour in a sex-specific manner, but whether neuroinflammation alone is sufficient to disrupt such behaviour is unknown. We investigated this question here using mice. First, the application of an endotoxin to primary cultures containing only hippocampal neurons did not affect their activation. However, when the same endotoxin was applied to mixed neuronal/glial cultures it did increase neuronal activation, providing initial indications of how it might be able to effect behavioural change. We next demonstrated neuroinflammatory effects on behaviour directly, demonstrating that intra-hippocampal administration of the same endotoxin increased locomotor activity and accelerated goal-directed learning in both male and female mice. In contrast, lipopolysaccharide-induced hippocampal neuroinflammation caused sex-specific disruptions to the acquisition of instrumental actions and to Pavlovian food-approach memories. Finally, we showed that LPS-induced hippocampal neuroinflammation had a sexually dimorphic effect on neuronal activation: increasing it in females and decreasing it in males.

Microglia Sing the Prelude of Neuroinflammation-Associated Depression

Major depressive disorder (MDD) is a psychiatric condition characterized by sadness and anhedonia and is closely linked to chronic low-grade neuroinflammation, which is primarily induced by microglia. Nonetheless, the mechanisms by which microglia elicit depressive symptoms remain uncertain. This review focuses on the mechanism linking microglia and depression encompassing the breakdown of the blood-brain barrier, the hypothalamic-pituitary-adrenal axis, the gut-brain axis, the vagus and sympathetic nervous systems, and the susceptibility influenced by epigenetic modifications on microglia. These pathways may lead to the alterations of microglia in cytokine levels, as well as increased oxidative stress. Simultaneously, many antidepressant treatments can alter the immune phenotype of microglia, while anti-inflammatory treatments can also have antidepressant effects. This framework linking microglia, neuroinflammation, and depression could serve as a reference for targeting microglia to treat depression.

The immune regulatory mechanism of ketamine-induced psychiatric disorders: A new perspective on drug-induced psychiatric symptoms

Ketamine, a psychoactive substance strictly regulated by international drug conventions, is classified as a "new type drug" due to its excitatory, hallucinogenic, or inhibitory effects. The etiology of ketamine-induced psychiatric symptoms is multifaceted, with the immune regulatory mechanism being the most prominent among several explanatory theories. In recent years, the interaction between the immune system and nervous system have garnered significant attention in neuropsychiatric disorder research. Notably, the infiltration of peripheral lymphocytes into the central nervous system has emerged as an early hallmark of certain neuropsychiatric disorders. However, a notable gap exists in the current literature, regarding the immune regulatory mechanisms, specifically the peripheral immune alterations, associated with ketamine-induced psychiatric symptoms. To address this void, this article endeavors to provide a comprehensive overview of the pathophysiological processes implicated in psychiatric disorders or symptoms, encompassing those elicited by ketamine. This analysis delves into aspects such as nerve damage, alterations within the central immune system, and the regulation of the peripheral immune system. By emphasizing the intricate crosstalk between the peripheral immune system and the central nervous system, this study sheds light on their collaborative role in the onset and progression of psychiatric diseases or symptoms. This insight offers fresh perspectives on the underlying mechanisms, diagnosis and therapeutic strategies for mental disorders stemming from drug abuse.

The association of Helicobacter pylori with adverse pregnancy outcomes in three European birth cohorts

BACKGROUND

Helicobacter pylori is a prevalent infection that may complicate pregnancy, but evidence remains limited, controversial and may not apply to all pregnant women.

OBJECTIVE

This study aims to evaluate whether Helicobacter pylori is a risk factor for adverse pregnancy outcomes and to identify vulnerable subpopulations.

STUDY DESIGN

Multiplex serology was utilized to measure blood levels of immunoglobulin G against eight Helicobacter pylori antigens in 1372 pregnant women from three European birth cohorts: BiB (United Kingdom), Rhea (Greece) and INMA (Spain). Outcomes of interest included gestational diabetes mellitus, gestational hypertension, preeclampsia, preterm birth and small for gestational age neonates, as well as prenatal anxiety and depression. Adjusted logistic regression models were used to evaluate the association between Helicobacter pylori seropositivity (overall and by antigen) and antigen specific antibody levels with the outcomes. We examined effect modification of the associations by ethnicity.

RESULTS

Helicobacter pylori seropositivity was detected in 18.8% (258/1372) of pregnant women. Preeclampsia was the least common outcome (26/830). Helicobacter pylori seropositivity was associated with the development of two or more adverse pregnancy outcomes (gestational hypertension, gestational diabetes, preterm birth, small gestational age and preeclampsia) [OR:1.32 (95% CI: 1.06-1.65), p-value: 0.01], especially in women with high antibody levels to OMP antigen [OR: 2.12 (95% CI: 1.62-2.76), p-value: 0.001]. Women with high antibody levels to Helicobacter pylori antigens GroEL and NapA were more likely to develop preeclampsia [OR: 2.34 (95% CI: 1.10-8.82), p-value: 0.03; OR: 4.09 (95% CI: 1.4-11.93), p-value 0.01)]. Helicobacter pylori seropositivity increased the odds of developing any hypertensive disorder during pregnancy among women of western ethnicity (948/1372) [OR:3.35 (95% CI: 1.29-8.74), p-value 0.03].

CONCLUSION

Our study suggests that Helicobacter pylori seropositivity is a risk factor for multiple adverse pregnancy outcomes and particularly in women of western origin for hypertensive disorders during pregnancy. Moreover, pathogen specific characteristics reflected in the antibody responses against OMP, GroEL and NapA seem to determine disease associations.

The risk of acute infection in association with first ever diagnosed depression: a cohort study

PURPOSE

To assess the risk of acute infections in patients with first ever diagnosed depression compared to patients with no diagnosed depression in a primary-care database.

METHODS

We conducted a cohort study using the UK CPRD GOLD database (2000-2019). We identified patients aged 18 years or older with a recorded Read code for depression (cohort entry date) and compared them to patients with no Read codes for depression using risk set sampling. Comparison groups were frequency-matched on age and sex, and comparison patients were required to have ≥ 1 general practitioner (GP) contact within 14 days before cohort entry. The primary outcome was a composite of outpatient diagnosed acute infections, including respiratory, gastrointestinal, urogenital infections and septicemia) within the two-years after cohort entry. We applied propensity score fine stratification and estimated incidence rates and IR ratios (IRR) using negative binomial regression.

RESULTS

In a weighted population of 285,922 patients with diagnosed depression and 285,921 comparison patients, the IR of acute infections was 97.3/1000 person-years (py) in patients with and 83.7/1000 py in patients with no diagnosed depression. The weighted IRR of acute infection was 1.18 (95% CI 1.16-1.20) comparing those with and with no diagnosed depression. Excluding patients with baseline comorbidities yielded an IRR even closer to the null: 1.07 (95% CI, 1.04-1.09).

CONCLUSIONS

Our results suggest that patients with diagnosed depression are not at a meaningfully increased risk of acute infections compared to patients with no diagnosed depression. Slightly increased overall relative risks of infections can be explained by residual differences in health care utilization and by the severity of comorbidities.

Resting-state functional connectivity is correlated with peripheral inflammatory markers in patients with major depressive disorder and healthy controls

BACKGROUND

Recent studies have highlighted the significant role of inflammation in the development and progression of major depressive disorder (MDD). Elevated levels of proinflammatory cytokines have consistently been observed in MDD, and these markers are shown to be linked to disruptions in brain networks. Therefore, we aimed to explore the relationship between inflammatory markers and resting-state functional connectivity (RSFC) in patients with MDD.

METHODS

This study included 76 patients with MDD and 92 healthy controls (HCs). Seed-to-voxel RSFC analysis was performed using brain regions that have been identified in previous studies on the neural networks implicated in MDD. These regions served as key hubs in the default mode, salience, cognitive control, and frontostriatal networks and were used as seed regions.

RESULTS

Compared with HCs, patients with MDD exhibited elevated levels of interleukin (IL)-6 and IL-8. The MDD group showed significant alterations of the RSFC between the prefrontal cortex (PFC), anterior cingulate cortex, visual cortex, postcentral gyrus, and striatal regions compared to the HC group. Additionally, within the MDD group, a positive correlation was observed between tumor necrosis factor (TNF)-α levels and the RSFC of the right dorsolateral prefrontal cortex (dlPFC) and visual cortex. Conversely, in the HC group, TNF-α levels were negatively correlated with the RSFC between the right dlPFC and bilateral dorsomedial prefrontal cortex, while positive correlations were noted between the RSFC of the right dlPFC with occipital regions and the levels of both IL-8 and TNF-α.

CONCLUSIONS

The present study confirmed that cytokine levels are linked to alterations in the RSFC, particularly in the prefrontal regions. Our findings suggest that systemic inflammation may contribute to functional disruptions in the brain networks involved in emotion regulation and cognitive control in MDD.

Particulate matter exposure and its consequences on hippocampal neurogenesis and cognitive function in experimental models

Exposure to air pollution is thought to cause millions of deaths globally each year. According to the Who 2018, approximately 7 million deaths annually are caused predominantly by noncommunicable diseases due to air pollution. Exposure to air particulate matter 2.5 (PM2.5) has been strongly associated with increased mortality and has significant effects on brain health. Air pollution, particularly ultrafine particulate matter, has emerged as a serious environmental concern with profound implications for human health. Studies in animal models have indicated that exposure to these pollutants during gestational development impacts prenatal and postnatal brain development. In particular, air pollution has been increasingly identified as a potential causative factor, as it affects neurogenesis in the brain's hippocampal region. The hippocampus is highly vulnerable to PM exposure, and any alteration in the structure or function of this region leads to various neurodevelopmental defects and neurodegenerative disorders via oxidative stress, microglial activation, neuronal death, and differential expression of genes. The neurogenesis process involves several steps, such as proliferation, differentiation, migration, synaptogenesis, and neuritogenesis. If any step of the neurogenesis process is hampered by environmental exposure or other factors, it can lead to neurodevelopmental defects, neurodegenerative disorders, and cognitive decline. One significant contributor to these alterations is air pollution, which ranks as the leading environmental risk factor worldwide. Some of the most common effects include oxidative stress, neuroinflammation, depressive behavior, altered cognitive processes, and microglial activation. This review explores how prenatal and postnatal PM exposure affects the hippocampal regions of the brain and the defects associated with exposure.

Association Between Serum Magnesium Levels and Depression in Patients Undergoing Peritoneal Dialysis: A Study Conducted at Handan First Hospital, China

Background

Depression exhibits notable prevalence among patients affected by chronic kidney disease(CKD) and end-stage renal disease (ESRD). Emerging reports suggest a potential association between magnesium (Mg) levels and depressive symptoms, there has been a surge of interest in exploring Mg supplementation as a complementary measure in depression treatment.

Objective

In this study our aim is to investigate the correlation between depressive symptoms and serum Mg level in patients undergoing peritoneal dialysis (PD) at Handan First Hospital, China. Additionally, we assessed the diagnostic significance of this relationship and identified pertinent influencing factors.

Methods

This study comprises a cohort of 140 individuals undergoing PD for a minimum duration of 3 months at the PD center of the Handan First Hospital. The Hamilton Depression Scale (HAMD) served as the assessment tool to evaluate the psychological status of the patients. Serum Mg levels, hemoglobin (Hb), and various demographic and clinical data were collected. Logistic regression and ROC analysis were performed to identify significant predictors of depression.

Results

The prevalence of depression was higher in patients with hypomagnesemia (60%) compared to those with normal or elevated Mg levels. Notably, a correlation emerged between abnormal serum Mg levels and the presence of depressive symptoms among individuals undergoing PD. Furthermore, binary logistic regression analysis revealed that serum Mg levels, hemoglobin (Hb) concentration, and unemployment significantly influenced the likelihood of occurrence of depression in patients undergoing PD (P< 0.05).

Conclusion

In addition, serum Mg levels demonstrate significant predictive value in anticipating onset of depression, indicating that rectifying low serum Mg levels among patients undergoing PD may serve as a preventive measure against depression. Further research is recommended to explore the therapeutic potential of Mg supplementation in this population.

Hypoxanthine Produces Rapid Antidepressant Effects by Suppressing Inflammation in Serum and Hippocampus

The occurrence and development of depression are closely related to disorders of the brain and peripheral substances. Abnormal metabolites in the blood affect the signal regulation function of the nerve center, which is one of the key factors for depression episodes. This study was focused on metabolites in serum and the mechanism of its antidepressant in the hippocampus. In the present study, serum metabolites in patients with depression were screened by metabolomic techniques. Various depressive mouse models and behavioral tests were used to assess its antidepressant effects. The expressions of inflammatory signaling were detected by using Western blot, ELISA, and immunofluorescence. We found that the metabolite hypoxanthine in the serum of patients with depression was significantly reduced, and the same result was also found in two mouse models of depression such as chronic unpredictable mild stress (CUMS) and social defeat stress (SD). By administering different doses of hypoxanthine (5, 10, 15 mg/kg), we found that only 15 mg/kg was able to significantly reduce the latency and increase food consumption in the novelty suppressed-feeding test (NSF), which was also able to reverse the depressive phenotypes of mice in the CUMS model after a single administration at 2 h later. Hypoxanthine obviously reduced the expressions of inflammation in serum and downregulated the expressions of MAPK and NLRP3-related pathways in the hippocampus in CUMS mice. Moreover, hypoxanthine also suppressed the activations of glial cells including GFAP and IBA-1 in hippocampal CA1, CA3, and dentate gyrus (DG). To sum up, hypoxanthine exerted antidepressant effect relying on the inhibition of peripheral and hippocampal inflammations by regulating MAPK, NLRP3-related pathways, and glial cells. This was the first time that we have found a disordered metabolite in patients with depression and further systematically demonstrated its efficacy and potential mechanism of antidepressants, providing new ideas for antidepressant drug development.

Peripheral Endothelial Dysfunction Is Associated With Incident Major Depressive Disorder

BACKGROUND

A subset of individuals with major depressive disorder (MDD) have a high burden of cardiovascular risk factors and cerebral small-vessel disease, implicating vascular disease in the development of depression. Cross-sectional studies demonstrate a link between endothelial dysfunction and MDD, but the prospective association between peripheral endothelial dysfunction (PED) and an incident diagnosis of MDD is unknown.

METHODS AND RESULTS

Patients undergoing a baseline assessment of cardiovascular risk were evaluated for PED using reactive hyperemia-peripheral arterial tonometry (≤1.8 consistent with PED). Patient medical records were reviewed to identify those who underwent a formal clinical evaluation of MDD after the index PED evaluation. The frequency of PED was compared in those with and without MDD. Logistic regression analyses were performed to assess the association between baseline PED and incident MDD. Between January 2006 and December 2020, 1614 patients underwent testing for PED. Four hundred eighty-four (30.1%) patients underwent a formal evaluation for MDD after (0-15 years) the index procedure (mean±SD age, 52.8±13.8 years; 65.2% women). Of these, 157 (32.4%) had PED and 108 (31.0%) were diagnosed with MDD. Individuals with MDD had a higher frequency of PED (40.2% versus 30.2%; P=0.034) compared with those without MDD. In multivariable analyses, PED was significantly associated with MDD (odds ratio, 2.3 [95% CI, 1.4-3.8]; P<0.001).

CONCLUSIONS

PED is significantly associated with incident MDD. Thus, PED may be a useful marker to identify individuals at increased risk of depression who may benefit from more frequent and earlier management strategies.

Mesenchymal stem cells improve depressive disorder via inhibiting the inflammatory polarization of microglia

Depressive disorder (DD) ranks among the most prevalent, burdensome, and costly psychiatric conditions globally. It manifests through a range of emotional, cognitive, somatic, and behavioral symptoms. Mesenchymal Stem Cells (MSCs) have garnered significant attention due to their therapeutic potential via immunomodulation in neurological disorders. Our research indicates that MSCs treatment demonstrates a notable effect on a Chronic Unpredictable Mild Stress (CUMS)-induced DD model in mice, surpassing even Fluoxetine in its antidepressant efficacy. MSCs mitigate DD by inhibiting central nervous system inflammation and facilitating the conversion of microglial cells into an Arg1high anti-inflammatory state. The MSCs-derived TGF-β1 is crucial for this Arg1high microglial cell transformation in DD treatment.

Higher inflammatory proteins predict future depressive symptom severity among adolescents with lower emotional clarity

BACKGROUND

A growing body of work has implicated inflammation in the pathogenesis of depression. As not all individuals with heightened levels of peripheral inflammation develop symptoms of depression, additional work is needed to identify other factors that catalyze the relationship between inflammation and depressive symptoms. Given that elevated levels of inflammatory activity can induce a variety of emotional changes, the present study examined whether emotional clarity, the trait-like ability to identify, discern, and express one's emotions, influences the strength of the association between inflammatory signaling and concurrent and prospective symptoms of depression.

METHODS

Community adolescents (N = 225, Mage = 16.63 years), drawn from a larger longitudinal project investigating sex and racial differences in depression onset, provided blood samples to determine peripheral levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) at a baseline visit, along with self-report measures of emotional clarity and depressive symptom severity. Depressive symptom severity was assessed again at a follow-up visit approximately 5-months after baseline.

RESULTS

Hierarchical multiple regressions detected a significant interaction between inflammatory markers and emotional clarity on future depression severity, controlling for baseline depressive symptoms. Specifically, among adolescents with low levels of emotional clarity, higher levels of IL-6, CRP, and inflammatory composite scores were significantly associated with greater future depression severity.

CONCLUSIONS

These results indicate that low emotional clarity and high inflammatory signaling may jointly confer risk for prospective depressive symptom severity among adolescents. Therapeutic interventions that improve emotional clarity may reduce risk of depressive symptoms among adolescents with low-grade peripheral inflammation.

Biomarkers as predictors of CBT responsiveness in major depressive disorder: The role of heart rate variability and inflammation

OBJECTIVE

Biological risk factors for cardiovascular disease may relate to poor treatment responsiveness in major depressive disorder (MDD). These factors encompass low-grade inflammation and autonomic dysregulation, as indexed by decreased heart rate variability (HRV) and increased heart rate (HR). This secondary analysis examined whether higher levels of inflammatory markers or autonomic alterations relate to lower responsiveness to cognitive behavioral therapy (CBT) among individuals with MDD.

METHODS

Eighty antidepressant-free patients with MDD were randomly assigned to 14 weeks of CBT or waitlist (WL). Potential biological moderators at study entry included HR and HRV (24-h, daytime, nighttime) and inflammatory markers such as C-reactive protein (CRP), interleukin (IL)-6, and tumor necrosis factor (TNF)-α. Forty non-clinical controls were involved to verify biological alterations in MDD at study entry. Depressive symptoms were assessed at baseline and at the end of treatment.

RESULTS

Individuals with MDD exhibited reduced total 24-h HRV (i.e., triangular index) and daytime HRV (i.e., triangular index, HF-HRV, LF-HRV, RMSSD), as well as increased levels of inflammatory markers. Patients who received CBT exhibited stronger reductions in self- and clinician-rated depressive symptoms, compared to WL. False discovery rate-adjusted moderation analyses did not show overall moderating effects of biological measures on treatment responsiveness. However, higher CRP levels were specifically associated with poorer improvement in somatic depressive symptoms.

CONCLUSIONS

There was no overall evidence for a moderating role of inflammation or autonomic features in CBT responsiveness in MDD. Higher levels of CRP might, however, specifically be associated with less improvement in somatic depressive symptoms during CBT.

Lactobacillus salivarius and Lactobacillus gasseri supplementation reduces stress-induced sugar craving in mice

OBJECTIVE

Increased intake of sweets or sugar craving may occur in response to chronic stress representing a risk factor for development of eating disorders and obesity. However, no safe treatment of stress-induced sugar craving is available. In this study we analysed effects of two Lactobacillus strains on food and sucrose intake in mice before and during their exposure to a chronic mild stress (CMS).

RESEARCH METHODS & PROCEDURES

C57Bl6 mice were gavaged daily for 27 days with a mix of L. salivarius (LS) LS7892 and L. gasseri (LG) LG6410 strains or with 0.9% NaCl as a control. Following 10 days of gavage, mice were individually placed into the Modular Phenotypic cages, and after 7 days of acclimation were exposed to a CMS model for 10 days. Food, water and 2% sucrose intakes as well as meal pattern were monitored. Anxiety and depressive-like behaviour were analysed by standard tests.

RESULTS

Exposure of mice to CMS was accompanied by increased size of sucrose intake in the control group likely reflecting the stress-induced sugar craving. A consistent, about 20% lower total sucrose intake, was observed in the Lactobacilli-treated group during stress which was mainly due to a reduced number of intakes. Lactobacilli treatment also modified the meal pattern before and during the CMS, showing a decrease of meal number and an increase of meal size with a tendency of reduced total daily food intake. Mild anti-depressive behavioural effects of the Lactobacilli mix were also present.

CONCLUSION

Supplementation of mice with LS LS7892 and LG LG6410 decreases sugar consumption suggesting a potential utility of these strains against stress-induced sugar craving.

Associations between oral health and depression and anxiety: A cross-sectional and prospective cohort study from the UK Biobank

AIM

To investigate the associations between oral health and depression, anxiety and their comorbidity in the UK Biobank cohort.

MATERIALS AND METHODS

Oral health problems were self-reported at baseline. Symptoms of depression and anxiety were assessed using the Mental Health Questionnaire (PHQ-4) in a cross-sectional study. In the cohort study, diagnoses of depression and anxiety disorders were based on hospital records. Logistic regression and Cox regression models were used to analyse the association between oral health and depression/anxiety.

RESULTS

A total of 305,188 participants were included in the cross-sectional study, and multivariate analysis showed that periodontal disease was associated with depression and/or anxiety (odds ratio [OR]: 1.79, 95% confidence interval [CI]: 1.73-1.86). In the prospective cohort study involving 264,706 participants, periodontal disease was significantly associated with an increased risk of depression and/or anxiety (hazard ratio [HR]: 1.14, 95% CI: 1.10-1.19), depression (HR: 1.19, 95% CI: 1.13-1.25) and anxiety (HR: 1.13, 95% CI: 1.07-1.19). Periodontal disease was also significantly associated with comorbid depression and anxiety (HR: 1.27, 95% CI: 1.16-1.38). Multiple mediation analysis using baseline inflammatory factors showed that white blood cell count and C-reactive protein explained 3.07% and 3.15% of the association between periodontal disease and depression and anxiety, respectively. However, the results of longitudinal multiple mediation analysis of inflammatory factors at first follow-up (N = 10,673) were not significant.

CONCLUSIONS

Periodontal disease was found to be consistently associated with an increased risk of depression, anxiety and their comorbidity.

A bio-behavioral model of systemic inflammation at breast cancer diagnosis and fatigue of clinical importance 2 years later

BACKGROUND

We aimed to generate a model of cancer-related fatigue (CRF) of clinical importance 2 years after diagnosis of breast cancer building on clinical and behavioral factors and integrating pre-treatment markers of systemic inflammation.

PATIENTS AND METHODS

Women with stage I-III hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer were included from the multimodal, prospective CANTO cohort (NCT01993498). The primary outcome was global CRF of clinical importance [European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ)-C30 ≥40/100] 2 years after diagnosis (year 2). Secondary outcomes included physical, emotional, and cognitive CRF (EORTC QLQ-FA12). All pre-treatment candidate variables were assessed at diagnosis, including inflammatory markers [interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon γ, IL-1 receptor antagonist, tumor necrosis factor-α, and C-reactive protein], and were tested in multivariable logistic regression models implementing multiple imputation and validation by 100-fold bootstrap resampling.

RESULTS

Among 1208 patients, 415 (34.4%) reported global CRF of clinical importance at year 2. High pre-treatment levels of IL-6 (quartile 4 versus 1) were associated with global CRF at year 2 [adjusted odds ratio (aOR): 2.06 (95% confidence interval [CI] 1.40-3.03); P = 0.0002; area under the receiver operating characteristic curve = 0.74]. Patients with high pre-treatment IL-6 had unhealthier behaviors, including being frequently either overweight or obese [62.4%; mean body mass index 28.0 (standard deviation 6.3 kg/m2)] and physically inactive (53.5% did not meet World Health Organization recommendations). Clinical and behavioral associations with CRF at year 2 included pre-treatment CRF [aOR versus no pre-treatment CRF: 3.99 (95% CI 2.81-5.66)], younger age [aOR per 1-year decrement: 1.02 (95% CI 1.01-1.03)], current tobacco smoking [aOR versus never: 1.81 (95% CI 1.26-2.58)], and worse insomnia or pain [aOR per 10-unit increment: 1.08 (95% CI 1.04-1.13), and 1.12 (95% CI 1.04-1.21), respectively]. Secondary analyses indicated additional associations of IL-2 [aOR per log-unit increment: 1.32 (95% CI 1.03-1.70)] and IL-10 [0.73 (95% CI 0.57-0.93)] with global CRF and of C-reactive protein [1.42 (95% CI 1.13-1.78)] with cognitive CRF at year 2. Emotional distress was consistently associated with physical, emotional, and cognitive CRF.

CONCLUSIONS

This study proposes a bio-behavioral framework linking pre-treatment systemic inflammation with CRF of clinical importance 2 years later among a large prospective sample of survivors of breast cancer.

Cytokine gene polymorphisms and suicide risk in an Indian ancestral population: A case-control study

BACKGROUND

India currently accounts for a majority of global suicide deaths. Research in European ancestry has established that suicide mortality has a significant genetic component, and suggests that inflammation may play a crucial role in the pathophysiology of suicide. Inflammation is also highly relevant in regions of increased pollution exposure, such as the megacities of India. To address the existing gaps in genetic research on suicide and possible association with inflammatory biomarkers, we examined genetic polymorphism and clinical risk phenotypes in a population-based suicide-death cohort, India.

MATERIAL AND METHODS

Genotyping of IL-1β(rs16944) & (rs1143627), IL-4(rs2070874), IL-6(rs1800795) and IL-10(rs1800896) was done in 234 post-mortem suicide-death cases and 256 post-mortem controls (N = 490) using PCR RFLP method.

RESULTS

Our analyses identified three significant (p < 0.001) associations of cytokine variants with suicide death, including IL-1β(rs16944), OR = 0.627; IL-4(rs2070874), OR = 0.524; and IL-6(rs1800795), OR = 2.509. Cases were more likely female and were more likely to have a history of psychiatric illness, though rate of psychiatric illness was low in suicide cases(9%).

CONCLUSION

Our genetic results are generally consistent with previous research on risk for depression and suicidal behaviour, and both genetic and phenotypic results provide new insights into risk factors that may contribute to suicide in India.

Immunological correlates of suicidality among adolescents with internalizing symptoms

Background

Suicide is a leading cause of death in adolescents and young adults globally. Well-established risk factors for suicide are depression and past suicide attempts. People experiencing suicidality may represent a distinct neurobiological group of people with depression. Because converging evidence has implicated inflammation in depression, we sought to investigate relationships between suicidality and immune markers in youth experiencing diverse mood and anxiety symptoms. We hypothesized that adolescents with suicidality would exhibit a unique immune signature.

Methods

Adolescents underwent semi-structured interviews and completed self-reported measures to assess psychopathology, including suicidality (suicidal ideation, plans, or attempts). Fasting blood samples were collected, cultured with and without lipopolysaccharide (LPS) to stimulate an inflammatory response, and analyzed for 41 immune analytes. To assess how immune function related to suicidality categorically and dimensionally, we conducted group comparisons and correlations while controlling for multiple comparisons using false discovery rate (FDR). To further uncover subtle immune-suicidality relationships, we employed a data-driven approach using factor analysis to extract major immune factors, each of which was subsequently correlated with suicidality measures.

Results

Among 126 participants, 29 were healthy controls and 97 participants had internalizing symptoms; within the clinical group, 57 experienced suicidality. Three immune analytes differed between healthy controls, suicidal, and non-suicidal adolescents with internalizing symptoms in the LPS condition: Flt-3L (p FDR = 0.0246), GM-CSF (p FDR = 0.0246), and IFN-γ (p FDR = 0.0246). These analytes were negatively correlated with the Beck Scale for Suicide Ideation (BSSI): Flt-3L (ρ = -0.19, p = 0.04); GM-CSF (ρ = -0.26, p = 0.004); IFN-γ (ρ =-0.33, p = 0.0003). GM-CSF also negatively correlated with number of suicide attempts (ρ = -0.39, p = 0.003). Factor analysis reduced 41 analytes to several common immune factors across experimental conditions, with Flt-3L, GM-CSF, and IFN-γ all loading heavily onto immune factors that were hypoactive in suicidality. Through this data-driven approach, we detected further associations between suicidality and immune factors across all conditions.

Conclusions

Peripheral immune function may be distinctly altered in adolescent suicidality. Future work should examine immune-suicidality relationships longitudinally.

Protective Effects of Probiotics on Runners' Mood: Immunometabolic Mechanisms Post-Exercise

BACKGROUND

The gut-brain axis may mediate mood changes due to strenuous exercise. Therefore, probiotic supplementation may mitigate mood worsening.

PURPOSE

The present study aims to evaluate the effect of probiotic supplementation on mood and immunometabolic parameters after a marathon.

MATERIALS AND METHODS

Fourteen marathon runners were selected and divided into placebo and probiotic groups that were supplemented for 30 days. Before and after the marathon, mood (POMS) was assessed, and blood was collected for analysis of immunometabolic parameters. Statistical analysis was performed, and p < 0.05 was considered to determine statistically differences.

RESULTS

Tension decreased after the marathon in both groups. Vigor decreased only in the placebo group. Fatigue increased after the marathon in both groups. TMD increased after the marathon in placebo. The IL2/IL-4 ratio decreased in the probiotic group after the marathon compared to before and increased compared to the placebo group. The IL-10 increased after the marathon in placebo. TNF-α increased after the marathon in probiotics. The TNF-α/IL-10 ratio decreased after the marathon in both groups. LPS decreased in the probiotic group after the marathon compared to before and in the placebo group.

CONCLUSIONS

Thirty days of probiotic supplementation attenuated the impact of marathons on mood worsening. The decrease in LPS in the probiotic group mediated the change in the pro/anti-inflammatory balance, indicating an immunometabolic mechanism by which the gut-brain axis impacts mood after strenuous exercise.

Inflammatory Biomarkers and Risk of Psychiatric Disorders

Importance

Individuals with psychiatric disorders have been reported to have elevated levels of inflammatory biomarkers, and prospective evidence is limited regarding the association between inflammatory biomarkers and subsequent psychiatric disorders risk.

Objective

To assess the associations between inflammation biomarkers and subsequent psychiatric disorders risk.

Design, Setting, and Participants

This was a prospective cohort study including individuals from the Swedish Apolipoprotein Mortality Risk (AMORIS) cohort, with no prior psychiatric diagnoses and having a measurement of at least 1 inflammatory biomarker. Data from the UK Biobank were used for validation. Longitudinal trajectories of studied biomarkers were visualized before diagnosis of psychiatric disorders in the AMORIS cohort via a nested case-control study. In addition, genetic correlation and mendelian randomization (MR) analyses were conducted to determine the genetic overlap and causality of the studied associations using publicly available GWAS summary statistics.

Exposures

Inflammatory biomarkers, eg, leukocytes, haptoglobin, immunoglobulin G (IgG), C-reactive protein (CRP), platelets, or albumin.

Main Outcomes and Measures

Any psychiatric disorder or specific psychiatric disorder (ie, depression, anxiety, and stress-related disorders) was identified through the International Statistical Classification of Diseases, Eighth, Ninth, and Tenth Revision codes.

Results

Among the 585 279 individuals (mean [SD] age, 45.5 [14.9] years; 306 784 male [52.4%]) in the AMORIS cohort, individuals with a higher than median level of leukocytes (hazard ratio [HR], 1.11; 95% CI, 1.09-1.14), haptoglobin (HR, 1.13; 95% CI, 1.12-1.14), or CRP (HR, 1.02; 95% CI, 1.00-1.04) had an elevated associated risk of any psychiatric disorders. In contrast, we found an inverse association for IgG level (HR, 0.92; 95% CI, 0.89-0.94). The estimates were comparable for depression, anxiety, and stress-related disorders, specifically, and these results were largely validated in the UK Biobank (n = 485 620). Analyses of trajectories revealed that individuals with psychiatric disorders had higher levels of leukocytes and haptoglobin and a lower level of IgG than their controls up to 30 years before the diagnosis. The MR analysis suggested a possible causal relationship between leukocytes and depression.

Conclusions and Relevance

In this cohort study, inflammatory biomarkers including leukocytes, haptoglobin, CRP, and IgG were associated with a subsequent risk of psychiatric disorders, and thus might be used for high-risk population identification. The possible causal link between leukocytes and depression supports the crucial role of inflammation in the development of psychiatric disorders.

Crosstalk between peripheral inflammation and brain: Focus on the responses of microglia and astrocytes to peripheral challenge

A growing body of evidence supports the link between peripheral inflammation and impairment of neurologic functions, including mood and cognitive abilities. The pathogenic event connecting peripheral inflammation and brain dysfunction is represented by neuroinflammation, a pathogenic phenomenon that provides an important contribution to neurodegeneration and cognitive decline also in Alzheimer's, Parkinson's, Huntington's diseases, as well as in Multiple Sclerosis. It is driven by resident brain immune cells, microglia and astrocytes, that acquire an activated phenotype in response to proinflammatory molecules moving from the periphery to the brain parenchyma. Although a huge progress has been made in clarifying cellular and molecular mechanisms bridging peripheral and central inflammation, a clear picture has not been achieved so far. Therefore, experimental models are of crucial relevance to clarify knowledge gaps in this regard. Many findings demonstrate that systemic inflammation induced by pathogen-associated molecular patterns, such as lipopolysaccharide (LPS), is able to trigger neuroinflammation. Therefore, LPS-administration is widely considered a useful tool to study this phenomenon. On this basis, the present review will focus on in vivo studies based on acute and subacute effects of systemic administration of LPS, with special attention on the state of art of microglia and astrocyte response to peripheral challenge.

Decoding paradoxical links of cytokine markers in cognition: Cross talk between physiology, inflammaging, and Alzheimer's disease- related cognitive decline

Recent research has revolutionized our understanding of memory consolidation by emphasizing the critical role of astrocytes, microglia, and immune cells in through cytokine signaling. Cytokines, compact proteins, play pivotal roles in neuronal development, synaptic transmission, and normal aging. This review explores the cellular mechanisms contributing to cognitive decline in inflammaging and Alzheimer's disease, highlighting the paradoxical effects of most studied cytokines (IL-1, IL-6, TNF-α) in brain function, which act as a double-edged sword in brain physiology, acting both as facilitators of healthy cognitive function and as a potential contributor to cognitive decline.

Quality of life and survivorship in patients with low-grade ovarian cancer

OBJECTIVE

High-grade (HGOC) and low-grade ovarian carcinoma (LGOC) are distinct malignancies with different biological features, treatment paradigms, and life expectancies. However, differences in quality of life (QOL), sleep, and depressive symptoms have not been examined by grade, and neither have inflammatory profiles associated with these symptoms. We aim to characterize QOL and biomarkers by OC grade.

METHODS

Participants included patients with HGOC (N = 578) or LGOC (N = 85). Participants completed baseline assessments of psychosocial factors prior to primary surgery or neoadjuvant chemotherapy and contributed saliva for cortisol and blood for interleukin-6 (IL-6) quantification. Samples were collected intraoperatively to quantify tumor cortisol. General linear models were used to examine differences in biological and psychological variables by grade.

RESULTS

At baseline, patients with LGOC reported less depression (p = 0.018) and sleep disturbances (p = 0.014), but no significant difference in depressive mood (p = 0.11) or QOL (p = 0.51) compared to patients with HGOC, adjusting for age and disease stage. There were trends towards lower tumor cortisol levels (p = 0.078) in LGOC compared to HGOC. One-year post-diagnosis, we found a significant improvement in QOL and fatigue, and a decrease in vegetative depression and IL-6 levels irrespective of grade.

CONCLUSIONS

We present the first characterization of psychosocial experiences of patients with LGOC. Despite having a better disease prognosis, patients with LGOC were just as likely to have mood disturbances as those with HGOC. There was a trend towards differences in tumor cortisol by grade. Our findings highlight the need to address well-being in patients with both low- and high-grade ovarian malignancies.

Association of Neutrophil-Percentage-To-Albumin Ratio(NPAR) with depression symptoms in U.S. adults: a NHANES study from 2011 to 2018

BACKGROUND

Inflammation is crucial in the development of depression. This study aims to examine the potential association between the Neutrophil-Percentage-to-Albumin Ratio(NPAR) and depression symptoms.

METHODS

This study adopted a cross-sectional design, involving patients with depression symptoms and those without depression symptoms with comprehensive NPAR data originated from the National Health and Nutrition Examination Survey(NHANES) spanning 2011 to 2018. The research utilized weighted multivariate logistic regression models and multivariate linear regression to investigate the linear relationship between NPAR levels and depression symptoms and its severity scores. The characterization of nonlinear relationships was accomplished by employing fitted smoothing curves. Furthermore, subgroup analyses and interaction assessments were conducted to offer additional insights.

RESULTS

This study involved a total of 10,829 participants, and the prevalence of depression among them was found to be 15.08%. The multiple logistic regression analysis revealed a statistically significant positive association between the continuum of NPAR and depression symptoms[OR:1.03, 95% CI: (1.00, 1.05)], as well as depression severity scores[β: 0.08, 95% CI: (0.04,0.11)]. Stratifying NPAR into quartiles, we found that higher NPAR associated with increased odds of depression symptoms. Furthermore, in subgroup analysis, there were no significant differences in the relationship between NPAR levels and depression symptoms or its severity scores within populations with or without diabetes and cardiovascular diseases. Additionally, the use of a two-stage linear regression model uncovered a non-linear relationship between NPAR and depression symptoms.

CONCLUSIONS

Our research indicates that NPAR levels were associated with depression symptoms. To corroborate our findings, larger prospective studies are warranted to elucidate nonlinear associations in greater detail.

The two-sided battlefield of tumour-associated macrophages in glioblastoma: unravelling their therapeutic potential

Gliomas are the most common primary malignant tumours of the central nervous system (CNS), which are highly aggressive, with increasing morbidity and mortality rates year after year, posing a serious threat to the quality and expected survival time of patients. The treatment of gliomas is a major challenge in the field of neuro-oncology, especially high-grade gliomas such as glioblastomas (GBMs). Despite considerable progress in recent years in the study of the molecular and cellular mechanisms of GBMs, their prognosis remains bleak. Tumour-associated macrophages (TAMs) account for up to 50% of GBMs, and they are a highly heterogeneous cell population whose role cannot be ignored. Here, we focus on reviewing the contribution of classically activated M1-phenotype TAMs and alternatively activated M2-phenotype TAMs to GBMs, and exploring the research progress in reprogramming M1 TAMs into M2 TAMs.

Examining systemic inflammation as a pathway linking peer victimization to depressive symptoms in adolescence

BACKGROUND

Adolescents exposed to victimization are at an increased risk for a variety of adverse mental health outcomes, including depressive symptoms. Yet, the biological pathways underlying these associations remain poorly understood. Focusing on within-person processes, we examined whether low-grade systemic inflammation mediated the longitudinal associations between peer victimization and depressive symptoms in adolescence.

METHODS

207 adolescents (at baseline Mage = 12.69 years; SD = 0.49; 43.5% female) participated in a multi-wave longitudinal study, with assessments repeated every 6 months over 1.5 years. At each assessment wave, participants self-reported their peer victimization experiences and depressive symptoms. Dried blood spots were collected at each wave using a finger prick procedure to assay a key marker of low-grade systemic inflammation, interkeukin-6 (IL-6). Data were analyzed using random-intercept cross-lagged panel models.

RESULTS

The cross-lagged paths from IL-6 to depressive symptoms were significant across all models and waves (β12 = .13; β23 = .12; β34 = .08), indicating that when adolescents' levels of low-grade systemic inflammation were above their person-specific average, they reported increased levels of depressive symptoms in the subsequent months. However, no significant cross-lagged within-person associations emerged between peer victimization and either IL-6 or depressive symptoms.

CONCLUSIONS

The findings provide no evidence for the hypothesized mediating role of inflammation in the within-person associations between peer victimization and depressive symptoms. Nevertheless, they extend prior research by indicating that elevated levels of low-grade systemic inflammation predict the development of depressive symptoms in adolescence.

The Potential Role of Polyphenol Supplementation in Preventing and Managing Depression: A Review of Current Research

Depression is a common mental illness that affects 5% of the adult population globally. The most common symptoms of depression are low mood, lack of pleasure from different activities, poor concentration, and reduced energy levels for an extended period, and it affects the emotions, behaviors, and overall well-being of an individual. The complex pathophysiology of depression presents challenges for current therapeutic options involving a biopsychosocial treatment plan. These treatments may have a delayed onset, low remission and response rates, and undesirable side effects. Researchers in nutrition and food science are increasingly addressing depression, which is a significant public health concern due to the association of depression with the increased incidence of cardiovascular diseases and premature mortality. Polyphenols present in our diet may significantly impact the prevention and treatment of depression. The primary mechanisms include reducing inflammation and oxidative stress, regulating monoamine neurotransmitter levels, and modulating the microbiota-gut-brain axis and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. This review summarizes recent advances in understanding the effects of dietary polyphenols on depression and explores the underlying mechanisms of these effects for the benefit of human health. It also highlights studies that are looking at clinical trials to help future researchers incorporate these substances into functional diets, nutritional supplements, or adjunctive therapy to prevent and treat depression.

Association of depressive symptoms and incident chronic kidney disease in middle-aged and older adults

BACKGROUND

Emerging evidence suggests that depressive symptoms may be a risk factor for the development of Chronic kidney disease (CKD). This study aimed to investigate the association between depressive symptoms and the incidence of CKD in middle-aged and older Chinese adults.

METHODS

We utilized data from the 2011-2020 China Health and Retirement Longitudinal Study (CHARLS). Depressive symptoms were assessed using the 10-item Center for Epidemiologic Studies Depression Scale (CES-D). Incident CKD was defined based on the estimated glomerular filtration rate ≤ 60 mL/min/m2 or self-reported. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95 % confidence intervals (95 % CI) for incident CKD, adjusting for potential confounders.

RESULTS

Among the 10,996 participants without baseline CKD, 890 developed CKD during a median follow-up of 9.0 years. After adjusting for potential covariates, participants with depressive symptoms had a significantly higher risk of developing CKD compared to those without depressive symptoms (HR: 1.450; 95 % CI: 1.249-1.682). The association remained statistically significant when the CES-D was scored according to the severity of depressive symptoms, i.e., quintiles. A linear positive association between total CES-D score and risk of incident CKD was also found using restricted cubic spline regression (Pfor non-linearity = 0.114).

CONCLUSIONS

Depressive symptoms are significantly associated with an increased risk of incident CKD in middle-aged and older Chinese adults. These findings underscore the importance of mental health screening and interventions in preventing CKD in this population.

Oxidative stress and inflammation mediate the association between elevated oxidative balance scores and improved sleep quality: evidence from NHANES

Background

The association between oxidative stress, as measured by the Oxidative Balance Score (OBS), and sleep quality remains unclear. The primary objective of this investigation was to clarify this relationship and to explore the potential involvement of oxidative stress and inflammation.

Methods

Data from 15,198 participants in the National Health and Nutrition Examination Survey 2007-2014 were analyzed. Sleep quality indicators, including sleep disorder, trouble, and duration, were assessed. The OBS, comprising information on 16 dietary nutrients and 4 lifestyle factors, was then calculated. Multivariable logistic and linear regression models were employed to investigate the correlation between OBS and sleep quality. Additionally, mediation analyses were conducted to evaluate the potential effects of oxidative stress and inflammation.

Results

We demonstrated a correlation between an elevated OBS and reduced sleep disorders (OR, 0.72; 95% CI, 0.58-0.91; p = 0.0055), reduced sleep trouble (OR, 0.81; 95% CI, 0.69-0.96; p = 0.0174), and prolonged sleep duration (β 0.009; 95% CI, 0.0002-0.0160; p = 0.015) when comparing the highest and lowest tertiles. Dietary factors exhibited autonomous correlations with sleep duration, whereas lifestyle factors displayed independent associations with sleep trouble and sleep disorders. Moreover, the relationships between OBS and both sleep disorders and trouble were influenced by albumin, γ-glutamyl transferase, total bilirubin, and white blood cells, with combined mediation effects of 34.66 and 29.54%, respectively (both p < 0.001). Sensitivity analyses revealed a significant association between OBS and sleep disorder (p < 0.001).

Conclusion

This study revealed a positive correlation between an elevated OBS and improved sleep quality, manifested by decreased sleep disorders, mitigated sleep trouble, and prolonged sleep duration. This is potentially mediated by oxidative stress and inflammation. Therefore, the study underscores the importance of adopting a diet rich in antioxidants and healthy lifestyle choices to address sleep-related concerns, providing a novel avenue for enhancing overall sleep quality.

Treatment-resistant depression: molecular mechanisms and management

Due to the heterogeneous nature of depression, the underlying etiological mechanisms greatly differ among individuals, and there are no known subtype-specific biomarkers to serve as precise targets for therapeutic efficacy. The extensive research efforts over the past decades have not yielded much success, and the currently used first-line conventional antidepressants are still ineffective for close to 66% of patients. Most clinicians use trial-and-error treatment approaches, which seem beneficial to only a fraction of patients, with some eventually developing treatment resistance. Here, we review evidence from both preclinical and clinical studies on the pathogenesis of depression and antidepressant treatment response. We also discuss the efficacy of the currently used pharmacological and non-pharmacological approaches, as well as the novel emerging therapies. The review reveals that the underlying mechanisms in the pathogenesis of depression and antidepressant response, are not specific, but rather involve an interplay between various neurotransmitter systems, inflammatory mediators, stress, HPA axis dysregulation, genetics, and other psycho-neurophysiological factors. None of the current depression hypotheses sufficiently accounts for the interactional mechanisms involved in both its etiology and treatment response, which could partly explain the limited success in discovering efficacious antidepressant treatment. Effective management of treatment-resistant depression (TRD) requires targeting several interactional mechanisms, using subtype-specific and/or personalized therapeutic modalities, which could, for example, include multi-target pharmacotherapies in augmentation with psychotherapy and/or other non-pharmacological approaches. Future research guided by interaction mechanisms hypotheses could provide more insights into potential etiologies of TRD, precision biomarker targets, and efficacious therapeutic modalities.

The 3 I's of immunity and aging: immunosenescence, inflammaging, and immune resilience

As we age, our immune system's ability to effectively respond to pathogens declines, a phenomenon known as immunosenescence. This age-related deterioration affects both innate and adaptive immunity, compromising immune function and leading to chronic inflammation that accelerates aging. Immunosenescence is characterized by alterations in immune cell populations and impaired functionality, resulting in increased susceptibility to infections, diminished vaccine efficacy, and higher prevalence of age-related diseases. Chronic low-grade inflammation further exacerbates these issues, contributing to a decline in overall health and resilience. This review delves into the characteristics of immunosenescence and examines the various intrinsic and extrinsic factors contributing to immune aging and how the hallmarks of aging and cell fates can play a crucial role in this process. Additionally, it discusses the impact of sex, age, social determinants, and gut microbiota health on immune aging, illustrating the complex interplay of these factors in altering immune function. Furthermore, the concept of immune resilience is explored, focusing on the metrics for assessing immune health and identifying strategies to enhance immune function. These strategies include lifestyle interventions such as diet, regular physical activity, stress management, and the use of gerotherapeutics and other approaches. Understanding and mitigating the effects of immunosenescence are crucial for developing interventions that support robust immune responses in aged individuals.

Stress-induced VIPergic activation mediates microbiota/Th17cell-dependent depressive-like behaviors

Chronic stress often has deleterious effects leading to the development of psychiatric diseases. The gut-brain axis represents a novel avenue for stress research. The negative effects of stress on the gut physiology have been well-described, whereas the pathways whereby stress controls microbial composition to modulate behaviors remains mainly unknown. We discovered that vasoactive intestinal peptide (VIP) activation promoted stress-induced microbial changes leading to increased infiltration of T helper (Th) 17 cells and microglial activation in the hippocampus and depressive-like behaviors, uncovering a close crosstalk between intestinal VIPergic release and the gut microbiota during stress and providing a new interaction between the nervous system and the gut microbiome after stress. Neutralization of the signature cytokine of Th17 cells, interleukin (IL)-17A, was sufficient to block depressive-like behaviors, reduce neuronal VIPergic activation and microglia activation induced by VIPergic activation after stress, opening new potential therapeutic targets for depression.

Astrogliosis marker [11C]SL25.1188 After COVID-19 With Ongoing Depressive and Cognitive Symptoms

BACKGROUND

After acute COVID-19, five percent of people experience persistent depressive symptoms and reduced cognitive function (COVID-DC). Theoretical models propose that astrogliosis is important in long COVID but measures primarily indicative of astrogliosis have not been studied in the brain of long COVID or COVID-DC. The objective is to measure [11C]SL25.1188 total distribution volume ([11C]SL25.1188 VT), index of monoamine oxidase B (MAO-B) density and marker of astrogliosis with PET in COVID-DC and compare to healthy controls.

METHODS

In 21 COVID-DC cases and 21 healthy controls, [11C]SL25.1188 VT was measured in prefrontal cortex, anterior cingulate cortex, hippocampus, dorsal putamen, and ventral striatum. Depressive symptoms were measured with the Beck Depression Inventory-II and cognitive symptoms were measured with neuropsychological tests.

RESULTS

[11C]SL25.1188 VT was higher in COVID-DC in prefrontal cortex, anterior cingulate cortex, hippocampus, dorsal putamen, and ventral striatum compared to healthy controls. Depressive symptom severity correlated negatively with [11C]SL25.1188 VT across prioritized brain regions. More recent acute COVID-19 correlated positively with [11C]SL25.1188 VT, reflecting higher values since predominance of the omicron variant. Exploratory analyses found greater [11C]SL25.1188 VT in hippocampus, dorsal putamen, and ventral striatum compared to major depressive episode controls with no history of COVID-19; and no relationship to cognitive testing in prioritized regions.

CONCLUSIONS

Results strongly support the presence of MAO-B labelled astrogliosis in COVID-DC throughout the regions assessed although the association of greater astrogliosis with less symptoms raises the possibility of a protective role. Magnitude of astrogliosis in COVID-DC is greater since emergence of omicron variant.

Exploring the reduction in aquaporin-4 and increased expression of ciliary neurotrophic factor with the frontal-striatal gliosis induced by chronic high-fat dietary stress

High-fat diet (HFD)-induced obesity induces peripheral inflammation and hypothalamic pathogenesis linking the activation of astrocytes and microglia. Clinical evidence indicates a positive correlation between obesity and psychiatric disorders, such as depression. The connectivity of the frontal-striatal (FS) circuit, involving the caudate putamen (CPu) and anterior cingulate cortex (ACC) within the prefrontal cortex (PFC), is known for its role in stress-induced depression. Thus, there is a need for a thorough investigation into whether chronic obesity-induced gliosis, characterized by the activation of astrocytes and microglia, in these brain regions of individuals with chronic obesity. The results revealed increased S100β+ astrocytes and Iba1+ microglia in the CPu and ACC of male obese mice, along with immune cell accumulation in meningeal lymphatic drainage. Activated GFAP+ astrocytes and Iba1+ microglia were observed in the corpus callosum of obese mice. Gliosis in the CPu and ACC was linked to elevated cleaved caspase-3 levels, indicating potential neural cell death by chronic HFD feeding. There was a loss of myelin and adenomatous polyposis coli (APC)+ oligodendrocytes (OLs) in the corpus callosum, an area known to be linked with injury to the CPu. Additionally, reduced levels of aquaporin-4 (AQP4), a protein associated within the glymphatic systems, were noted in the CPu and ACC, while ciliary neurotrophic factor (CNTF) gene expression was upregulated in these brain regions of obese mice. The in vitro study revealed that high-dose CNTF causing a trend of reduced astrocytic AQP4 expression, but it significantly impaired OL maturation. This pathological evidence highlights that prolonged HFD consumption induces persistent FS gliosis and demyelination in the corpus callosum. An elevated level of CNTF appears to act as a potential regulator, leading to AQP4 downregulation in the FS areas and demyelination in the corpus callosum. This cascade of events might contribute to neural cell damage within these regions and disrupt the glymphatic flow.

Neuroimmunomodulation: The History of Science in Psychoneuroimmunology

BACKGROUND

From the original studies investigating the effects of adrenal gland secretion to modern high-throughput multidimensional analyses, stress research has been a topic of scientific interest spanning just over a century.

SUMMARY

The objective of this review was to provide historical context for influential discoveries, surprising findings, and preclinical models in stress-related neuroimmune research. Furthermore, we summarize this work and present a current understanding of the stress pathways and their effects on the immune system and behavior. We focus on recent work demonstrating stress-induced immune changes within the brain and highlight studies investigating stress effects on microglia. Lastly, we conclude with potential areas for future investigation concerning microglia heterogeneity, bone marrow niches, and sex differences.

KEY MESSAGES

Stress is a phenomenon that ties together not only the central and peripheral nervous system, but the immune system as well. The cumulative effects of stress can enhance or suppress immune function, based on the intensity and duration of the stressor. These stress-induced immune alterations are associated with neurobiological changes, including structural remodeling of neurons and decreased neurogenesis, and these contribute to the development of behavioral and cognitive deficits. As such, research in this field has revealed important insights into neuroimmune communication as well as molecular and cellular mediators of complex behaviors relevant to psychiatric disorders.

Serum TNFα and IL-17A levels may predict increased depressive symptoms: findings from the Shika Study cohort project in Japan

BACKGROUND

Low-grade systemic inflammation may be a key player in the immune activation that has been reported for mental health deterioration. We hypothesised that elevated serum levels of inflammatory cytokines increase neuroinflammation and exacerbate depressive symptoms.

METHODS

The participants were part of a cohort study for whom data was available for both 2015 and 2019. In 2015, blood samples were collected from 232 participants. Their depressive symptoms were assessed both 2015 and 2019 using the Centre for Epidemiologic Studies Depression Scale (CES-D) (n = 33). The multiplex immunoassay system (Luminex® 200) was used to measure the serum concentrations of IL-6, IL-10, IL-12, IL-17A and TNFα. Data were analysed using linear models with the level of significance considered to be p < 0.05.

RESULTS

After controlling for age, BMI, smoking and alcohol consumption, in 2015 the serum concentrations of IL-17A and TNFα in 2015 were significantly positively associated with the CES-D scores of women (standardised β (B) = .027, p < 0.01 and B = 0.26, p < 0.01, respectively). The serum concentrations of IL-17A and TNFα of men were significantly positively associated with the CES-D scores of 2019 (B = 0.62, p = 0.02 and B = 0.59, p = 0.02, respectively).

CONCLUSIONS

In this cross-sectional study, we found a significant positive correlation between the depressive symptoms and serum TNFα and IL-17A levels of women. In addition, our longitudinal findings suggest the possibility that TNFα and IL-17A could elevate the depressive symptoms of men.

Mood, Cognitive Function, and Plasma Kynurenine Metabolites Responses Following Severe Changes in Physical Activity

PURPOSE

To monitor changes in mood, cognitive function, brain electrical activity, and circulating kynurenine pathway metabolites in response to a 3-wk severe physical activity (PA) restriction, followed by 3 wk of resumed activity adding resistance and high-intensity interval exercise training.

METHODS

Twenty healthy participants (14 males, 6 females; 25.4 ± 5.2 yr) underwent 3 wk of limited PA using forearm crutches with one leg suspended (INACT) and then 3 wk of resumed activity plus supervised resistance and high-intensity interval training sessions (ACT, three to six sessions per week). At baseline, after INACT, and then after ACT, venous blood was sampled for analysis of major kynurenine pathway metabolites, a short version of the International Physical Activity Questionnaire, Hospital Anxiety and Depression Scale (HADS) and Profile of Mood States (POMS) questionnaires were completed, and cognitive tests with electroencephalography were performed.

RESULTS

During INACT, the depression score on the HADS scale tended to increase (3.5 to 6.8; P = 0.065), whereas it was reduced with ACT compared with after INACT (2.8; P = 0.022). On the POMS scale, depression, fatigue, and confusion increased within INACT ( P < 0.05). Notably, subjects exhibited considerable variability, and those experiencing depression symptoms recorded by the HADS scale ( n = 4) displayed distinct mood disturbances on POMS. All HADS and POMS scores were fully restored to baseline with ACT. Neither INACT nor ACT induced significant changes in cognition, brain electrical activity, or kynurenine pathway metabolites ( P > 0.05).

CONCLUSIONS

Although young healthy individuals with 3 wk of severely restricted PA do not undergo changes in circulating kynurenine pathway metabolites, cognitive performance, and brain electrical activity, their mood response is quite variable, and depression develops in some. Three weeks of resuming mobility plus exercise training reversed the mood profile.