High serum uric acid level in adolescent depressive patients

The impact of psychological stress on physiological indicators in healthcare workers: a cross-sectional study

Background

Medical health workers play an essential role in the healthcare system and face unique workplace stressors. However, the impact of psychological stress on their physical health has received less attention compared to the general population.

Methods

We retrospectively analyzed the Self-rating Depression Scale (SDS) questionnaires and blood testing results from 1963 medical health workers. Multivariate linear regression analysis using a backward stepwise selection strategy to identify physical examination indicators that were significantly affected by depression.

Results

Depression severity, as measured by SDS index score, was positively correlated with the levels of hemoglobin (coefficient 0.0027, p = 0.0412), platelet count (coefficient 0.0005, p = 0.0198), and uric acid (coefficient 0.0004, p = 0.0492), while negatively correlated with red blood cell count (coefficient-0.0895, p = 0.0406). Similar results were observed in the subgroup analysis stratified by age and sex.

Conclusion

Our study found a significant association between higher levels of depression and specific physiological indicators in healthcare professionals, including elevated hemoglobin, platelet counts, and uric acid levels, as well as decreased red blood cell counts. These changes in blood parameters may reflect underlying physiological stress and inflammation, potentially increasing overall health risks for healthcare workers. Addressing these physiological changes may be crucial for mitigating the health risks associated with depression. To validate our findings and develop targeted interventions, larger multi-center studies are needed to further explore the relationship between depression severity and blood parameters in healthcare professionals.

Prevalence, demographic characteristics, and clinical features of suicide risk in first episode drug-naïve schizophrenia patients with comorbid severe anxiety

BACKGROUND

Both anxiety symptoms and suicide risk are common in schizophrenia. However, previous findings about the association between anxiety and suicide risk in schizophrenia were controversial. This study is the first to examine the prevalence of suicide risk and related demographic, clinical features in a large sample of first episode drug-naïve (FEDN) schizophrenia patients with comorbid severe anxiety.

METHODS

In total, 316 patients with FEDN schizophrenia were enrolled in this study. Patients' symptoms were assessed using the Hamilton Depression Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS). Serum levels of glucose, insulin, uric acid, and lipids including total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), were evaluated.

RESULTS

In the current study, 56.3% patients presented comorbid severe anxiety. The rate of suicide risk was higher in the severe anxiety group (55.6%) than in the mild-moderate anxiety group (33.3%). The interactions among severe anxiety, uric acid and HDL-C were associated with suicide risk. Compared with patients with normal uric acid, those with abnormal uric acid exhibited a stronger association between HAMA scores and HAMD-suicide item scores. This enhanced association was also observed for patients with abnormal HDL-C levels.

CONCLUSIONS

In FEDN schizophrenia patients with comorbid severe anxiety, our findings suggested a high incidence of suicide risk. Abnormal levels of uric acid and low levels of HDL-C, as well as high depression may be associated with an increased risk of suicide in FEDN schizophrenia patients with comorbid severe anxiety.

Serum Thiols and Ischemia-Modified Albumin Levels in Children With Major Depressive Disorder: A Cross-Sectional Study

Introduction This cross-sectional study aimed to investigate potential biomarkers of oxidative stress by analyzing serum thiol-disulfide homeostasis (TDH) and ischemia-modified albumin (IMA) levels in children who have been diagnosed with major depressive disorder (MDD). Methods The study included 24 medication-naive children aged seven to 17 years diagnosed with MDD and 19 healthy controls matched for age, gender, and body mass index. Clinical interviews were conducted using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL-DSM-5), and diagnoses were made according to DSM-5. The Child Depression Inventory (CDI) and the Clinical Global Impression Scale-Severity (CGI-S) were also administered to the participants. Venous blood samples were taken from all subjects to assess TDH and IMA levels, considered potential oxidative stress indicators. Results The study showed no significant difference in TDH and IMA levels between the MDD and the control groups. Although not statistically significant, it was observed that native thiol and total thiol levels were higher in the MDD group. No direct relationship was found between disease severity and either TDH or IMA levels. Conclusion In conclusion, while there were no significant differences in the levels of TDH and IMA, higher levels of both native and total thiols were found in the MDD group.

Evaluation of metabolomics-based urinary biomarker models for recognizing major depression disorder and bipolar disorder

BACKGROUND

Major depressive disorder (MDD) and bipolar disorder (BD) are psychiatric disorders with overlapping symptoms, leading to high rates of misdiagnosis due to the lack of biomarkers for differentiation. This study aimed to identify metabolic biomarkers in urine samples for diagnosing MDD and BD, as well as to establish unbiased differential diagnostic models.

METHODS

We utilized a metabolomics approach employing ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) to analyze the metabolic profiles of urine samples from individuals with MDD (n = 50), BD (n = 12), and healthy controls (n = 50). The identification of urine metabolites was verified using MS data analysis tools and online metabolite databases.

RESULTS

Two diagnostic panels consisting of a combination of metabolites and clinical indicators were identified-one for MDD and another for BD. The discriminative capacity of these panels was assessed using the area under the receiver operating characteristic (ROC) curve, yielding an area under the curve (AUC) of 0.9084 for MDD and an AUC value of 0.9017 for BD.

CONCLUSIONS

High-resolution mass spectrometry-based assays show promise in identifying urinary biomarkers for depressive disorders. The combination of urine metabolites and clinical indicators is effective in differentiating healthy controls from individuals with MDD and BD. The metabolic pathway indicating oxidative stress is seen to significantly contribute to depressive disorders.

Association between kidney stones and poor sleep factors in U.S. adults

The purpose of our study is to examine the correlation between sleep factors and the prevalence of kidney stones in US adults. A total of 34,679 participants from the National Health and Nutrition Examination Survey 2007 to 2018 were included in the analyses. Sleep data collection included: presleep factors (difficulty falling asleep, sleep onset latency), intra-sleep factors (risk index of obstructive sleep apnea, restless leg syndrome, difficulty maintaining sleep), post-sleep factors (daytime sleepiness, non-restorative sleep), sleep schedule and duration, and sleep quality. Logistic regression models were used to analyze the correlation between sleep factors and the prevalence of kidney stones. Among the 34,679 participants, the overall incidence of kidney stones was 9.3%. The presence of presleep factors (difficulty falling asleep [odds ratios [OR], 1.680; 95% CI, 1.310-2.150], prolonged sleep onset latency [OR, 1.320; 95% CI, 1.020-1.700]), intra-sleep factors (higher risk index of obstructive sleep apnea [OR, 1.750; 95% CI, 1.500-2.050], restless leg syndrome [OR, 1.520; 95% CI, 1.150-1.990], difficulty maintaining sleep [OR, 1.430; 95% CI, 1.130-1.810]), post-sleep factors (daytime sleepiness [OR, 1.430; 95% CI, 1.220-1.680], non-restorative sleep [OR, 1.400; 95% CI, 1.110-1.760]), short sleep duration (OR, 1.190; 95% CI, 1.080-1.310), mediate sleep quality (OR, 1.140; 95% CI, 1.020-1.290), and poor sleep quality (OR, 1.500; 95% CI, 1.310-1.720) are linked to the occurrence of kidney stones. However, short sleep onset latency, bedtime and wake-up time were not significantly associated with the prevalence of kidney stones. These findings showed positive associations between higher kidney stone prevalence and poor sleep factors.

Association between serum uric acid levels and depressive symptoms according to menopausal status

INTRODUCTION

The menopause-specific relationship between serum uric acid (SUA) and depressive symptoms were not known. We aimed to explore the association between SUA and depressive symptoms stratified by menopausal status.

METHODS

This is a cross-sectional study, a total of 4845 females were enrolled from China health and retirement longitudinal study (CHARLS) in China. The Center for Epidemiologic Studies Depression Scale (CESD) were used to measure depressive symptoms. A cut-off score of CES-D ≥ 10 was defined as depression. Multiple regression models were used to assess the relationship between SUA and depression stratified by menopausal status.

RESULTS

Overall, SUA was significantly associated with depressive symptoms/depression in post-menopause women (β = -0.39, 95 % CI: -0.60, -0.17) after adjusted potential confounders. Compared with those whose SUA levels were in the first tertile, participants with their SUA in the second (β = -0.76, 95 % CI: -1.30, -0.22) and third tertile (β = -1.24, 95 % CI: -1.80, -0.68) had milder depressive symptoms. However, SUA was not associated with depressive symptoms in pre-menopause women (β = 0.1, 95 % CI: -0.25, 0.46). An interaction between menopausal status and SUA on depressive symptoms were found in this study (P = 0.02). Similar results were found for depression.

LIMITATIONS

Some potential covariates like diet that could affect SUA levels were not considered in this study.

CONCLUSIONS

Higher SUA was associated with depressive symptoms/depression in post-menopause women. An interaction between menopausal status and SUA on depressive symptoms were found. SUA was not associated with depressive symptoms/depression in pre-menopause women.

Precision Medicine in Depression: The Role of Proteomics and Metabolomics in Personalized Treatment Approaches

Depression, or major depressive disorder (MDD), is a widespread mental health condition marked by enduring feelings of sorrow and loss of interest. Treatment of depression frequently combines psychotherapy, medication, and lifestyle modifications. However, the occurrence of treatment resistance in certain individuals makes it difficult for physicians to effectively manage this disorder, calling for the implementation of alternative therapeutic strategies. Recently, precision medicine has gained increased attention in the field of mental health, paving the way for more personalized and effective therapeutic interventions in depression. Also known as personalized medicine, this approach relies on genetic composition, molecular profiles, and environmental variables to customize therapies to individual patients. In particular, precision medicine has offered novel viewpoints on depression through two specific domains: proteomics and metabolomics. On one hand, proteomics is the thorough study of proteins in a biological system, while metabolomics focuses on analyzing the complete set of metabolites in a living being. In the past few years, progress in research has led to the identification of numerous depression-related biomarkers using proteomics and metabolomics techniques, allowing for early identification, precise diagnosis, and improved clinical outcome. However, despite significant progress in these techniques, further efforts are required for advancing precision medicine in the diagnosis and treatment of depression. The overarching goal of this chapter is to provide the current state of knowledge regarding the use of proteomics and metabolomics in identifying biomarkers related to depression. It also highlights the potential of proteomics and metabolomics in elucidating the intricate processes underlying depression, opening the door for tailored therapies that could eventually enhance clinical outcome in depressed patients. This chapter finally discusses the main challenges in the use of proteomics and metabolomics and discusses potential future research directions.

Implication of red meat consumption habits in serum uric acid levels and mood disorders among first-trimester pregnant women

BACKGROUND

Dietary pattern involving meat consumption has an association with serum uric acid level which subsequently has an impact on moods. However, this relationship is not clearly established in pregnant women, particularly those who are accustomed to daily meat consumption.

OBJECTIVE

This study investigated the relationship between red meat consumption and uric acid level and the subsequent impact on mood disorders in 1st trimester pregnant women.

METHODOLOGY

A total of 92 pregnant women in their first trimester (8-12 weeks), were selected for this study. Socio-demographic characteristics including age, body mass index (BMI), educational qualification, sleep hours, blood pressure and exercise status were recorded. To assess meat consumption, classification based on the recruited population consumption was divided into low and high meat consumption groups. Serum uric acid level was estimated in plasma. Mood disorder, namely, depression and anxiety were assessed using a self-reported Hospital Anxiety and Depression Scale (HADS) questionnaire. Collected data was analysed using different statistical tools.

RESULTS

Logistic regression analysis showed higher odds of depression (OR = 0.059, 95% CI 0.02-0.172, p < 0.001) and anxiety (OR = 0.144, 95% CI 0.055-0.375, p < 0.001) in the high meat consumption group. Further, the potential confounders, high BMI and less exercise increased the odds of depression and anxiety in high meat consumption groups. Linear regression analysis revealed a significant influence of meat consumption on uric acid level (F (1, 90) = 305.385, p < 0.01).

CONCLUSIONS

The study recommends regular clinical screening of mood disorders, and recommends reasonable consumption of lean meat and/or replacing some portions with fish, as well as, a commitment to eating a healthy, balanced diet. It also suggests extensive studies because it could be linked to postpartum mood disorders among those who consume red meat every day.

Inflammation in the pathogenesis of depression: a disorder of neuroimmune origin

There are several hypotheses concerning the underlying pathophysiological mechanisms of major depression, which centre largely around adaptive changes in neuronal transmission and plasticity, neurogenesis, and circuit and regional connectivity. The immune and endocrine systems are commonly implicated in driving these changes. An intricate interaction of stress hormones, innate immune cells and the actions of soluble mediators of immunity within the nervous system is described as being associated with the symptoms of depression. Bridging endocrine and immune processes to neurotransmission and signalling within key cortical and limbic brain circuits are critical to understanding depression as a disorder of neuroimmune origins. Emergent areas of research include a growing recognition of the adaptive immune system, advances in neuroimaging techniques and mechanistic insights gained from transgenic animals. Elucidation of glial-neuronal interactions is providing additional avenues into promising areas of research, the development of clinically relevant disease models and the discovery of novel therapies. This narrative review focuses on molecular and cellular mechanisms that are influenced by inflammation and stress. The aim of this review is to provide an overview of our current understanding of depression as a disorder of neuroimmune origin, focusing on neuroendocrine and neuroimmune dysregulation in depression pathophysiology. Advances in current understanding lie in pursuit of relevant biomarkers, as the potential of biomarker signatures to improve clinical outcomes is yet to be fully realised. Further investigations to expand biomarker panels including integration with neuroimaging, utilising individual symptoms to stratify patients into more homogenous subpopulations and targeting the immune system for new treatment approaches will help to address current unmet clinical need.

Xanthine-induced deficits in hippocampal behavior and abnormal expression of hemoglobin genes

The prevalence of mental disorders such as depression and anxiety is high and often comorbid with other diseases. Chronic stress is a common risk factor for these disorders, but the mechanisms behind their development are not yet fully understood. Metabolomics has revealed a close association between purine and pyrimidine metabolism and depression and anxiety, with increased levels of serum xanthine observed in both humans and mice. Xanthine is known as purine metabolism, and this compound shows several biological activities, but the impact of xanthine on our brain function is still unclear. The hippocampus, which plays a crucial role in memory and learning, is also implicated in the pathophysiology of depression and anxiety. Here, we investigated the effects of xanthine intraperitoneal administration on spatial memory and anxiety-like behavior in mice. The findings indicated that xanthine administration induced a deficit of hippocampus-dependent spatial memory and a tendency to anxiety-like behavior in mice. RNA-seq analysis showed that xanthine administration upregulated hemoglobin (Hb) genes involved in oxygen transport in the hippocampus. The upregulated Hb genes occurred in the neuronal cells, and in vitro experiments revealed that both Hba-a1 derived from mice and HBA2 derived from humans were upregulated by xanthine treatment. These observations suggest that the xanthine-induced Hb in the hippocampus could be related to spatial memory deficit and anxiety. This study sheds light on the direct effects of xanthine on the brain and its potential role in the development of depression and anxiety symptoms caused by chronic stress.

Major Depressive Disorder and Oxidative Stress: A Review of Peripheral and Genetic Biomarkers According to Clinical Characteristics and Disease Stages

Major depressive disorder (MDD) is currently the main cause of disability worldwide, but its pathophysiology remains largely unknown, especially given its high heterogeneity in terms of clinical phenotypes and biological characteristics. Accordingly, its management is still poor. Increasing evidence suggests that oxidative stress, measured on various matrices such as serum, plasma or erythrocytes, has a critical role in MDD. The aim of this narrative review is to identify serum, plasma and erythrocyte biomarkers of oxidative stress in MDD patients according to disease stage and clinical features. Sixty-three articles referenced on PubMed and Embase between 1 January 1991, and 31 December 2022, were included. Modifications to antioxidant enzymes (mainly glutathione peroxidase and superoxide dismutase) in MDD were highlighted. Non-enzymatic antioxidants (mainly uric acid) were decreased in depressed patients compared to healthy controls. These changes were associated with an increase in reactive oxygen species. Therefore, increased oxidative damage products (principally malondialdehyde, protein carbonyl content and 8-hydroxy-2'-deoxyguanosine) were present in MDD patients. Specific modifications could be identified according to disease stages and clinical features. Interestingly, antidepressant treatment corrected these changes. Accordingly, in patients in remission from depression, oxidative stress markers were globally normalized. This narrative review suggests the particular interest of oxidative stress biomarkers for MDD care that may contribute to the heterogeneity of the disease and provide the opportunity to find new therapeutic targets.

The gut microbiome and child mental health: A population-based study

The link between the gut microbiome and the brain has gained increasing scientific and public interest for its potential to explain psychiatric risk. While differences in gut microbiome composition have been associated with several mental health problems, evidence to date has been largely based on animal models and human studies with modest sample sizes. In this cross-sectional study in 1,784 ten-year-old children from the multi-ethnic, population-based Generation R Study, we aimed to characterize associations of the gut microbiome with child mental health problems. Gut microbiome was assessed from stool samples using 16S rRNA sequencing. We focused on overall psychiatric symptoms as well as with specific domains of emotional and behavioral problems, assessed via the maternally rated Child Behavior Checklist. While we observed lower gut microbiome diversity in relation to higher overall and specific mental health problems, associations were not significant. Likewise, we did not identify any taxonomic feature associated with mental health problems after multiple testing correction, although suggestive findings indicated depletion of genera previously associated with psychiatric disorders, including Hungatella, Anaerotruncus and Oscillospiraceae. The identified compositional abundance differences were found to be similar across all mental health problems. Finally, we did not find significant enrichment for specific microbial functions in relation to mental health problems. In conclusion, based on the largest sample examined to date, we do not find clear evidence of associations between gut microbiome diversity, taxonomies or functions and mental health problems in the general pediatric population. In future, the use of longitudinal designs with repeated measurements of microbiome and psychiatric outcomes will be critical to identify whether and when associations between the gut microbiome and mental health emerge across development and into adulthood.

Serum uric acid is not associated with major depressive disorder in European and South American populations: a meta-analysis and two-sample bidirectional Mendelian Randomization study

OBJECTIVE

Although previous epidemiological studies have demonstrated that serum uric acid (SUA) is associated with major depressive disorder (MDD), these analyses are prone to biases. Here, we applied the Mendelian Randomization approach to determine whether SUA is causally associated with MDD.

METHODS

We conducted a meta-analysis to evaluate the relationship between SUA and MDD, then applied summary data from the Global Urate Genetics Consortium and the Psychiatric Genomics Consortium to estimate their causal effect using a two-sample bidirectional Mendelian Randomization (MR) analysis. Thereafter, the causal effect was further researched using genetic risk scores (GRS) as instrumental variables (IVs).

RESULTS

Results of a meta-analysis of articles comprising 6975 and 13,589 MDD patients and controls, respectively, revealed that SUA was associated with MDD (SMD = -0.690, 95% CI: -0.930 to -0.440, I2 = 97.4%, P < 0.001). In addition, the five MR methods revealed no causal relationship existed between SUA and MDD, which corroborated the results obtained via the GRS approach.

CONCLUSION

This paper found little evidence that this association between SUA and MDD is casual. Genetically, there was no significant causal association between SUA and MDD.

Air pollution, genetic factors and the risk of depression

Both genetics and ambient air pollutants contribute to depression, but the degree to which genetic susceptibility modifies the effect of air pollution on depression remains unknown. We aimed to investigate the effect of the modification of genetic susceptibility on depression. Notably, 490,780 participants who were free of depression at baseline in the UK Biobank study were recruited from 2006 to 2010. A land use regression (LUR) model was performed to estimate the concentrations of particulate matter with diameters ranging from ≤2.5-≤10 μm (PM_2.5, PM_2.5-10 and PM₁₀), nitrogen dioxide (NO₂), and nitrogen oxides (NO_x). The International Classification of Diseases 10th Revision (ICD-10) code was used to identify depression cases. Cox proportional hazard models adjusted for covariates were used to investigate the association between ambient air pollutants and depression. Moreover, the polygenic risk score (PRS) was calculated to evaluate cumulative genetic effects, and additive interaction models were established to explore whether genetic susceptibility modified the effects of air pollutants on depression. PM_2.5, PM₁₀, NO₂ and NO_x exposure were significantly positively associated with the risk of depression, and the hazard ratios and 95 % confidence intervals for a 10-μg/m³ increase in PM_2.5, PM₁₀, NO₂ and NO_x concentrations were 2.12 (1.82, 2.47), 1.12 (1.03, 1.23), 1.07 (1.05, 1.10) and 1.04 (1.03, 1.05), respectively. Air pollutants and genetic variants exerted significant additive effects on the risk of depression (relative excess risk due to the interaction [RERI]: 0.15 for PM_2.5, 0.12 for PM₁₀, 0.10 for NO₂, and 0.12 for NO_x; attributable proportion due to the interaction [AP]: 0.12 for PM_2.5, 0.10 for PM₁₀, 0.08 for NO₂, and 0.09 for NO_x). Air pollution exposure was significantly associated with the risk of depression, and participants with a higher genetic risk were more likely to develop depression when exposed to high levels of air pollution.

Oxidative stress parameters and antioxidants in adults with unipolar or bipolar depression versus healthy controls: Systematic review and meta-analysis

BACKGROUND

To study differences in oxidative stress markers and antioxidants among patients with bipolar depression (BPD) and unipolar depression (UPD).

METHODS

Data sources. Electronic MEDLINE/PubMed/Cochrane Library/Scopus/TripDatabase database search until 30/06/2021.

STUDY SELECTION

Included were articles comparing antioxidant or oxidative stress markers between adults with BPD or UPD and healthy controls (HCs).

DATA EXTRACTION

Two authors extracted data independently. Random effects meta-analysis, calculating standardized mean differences for results from ≥3 studies.

RESULTS

Oxidative stress markers reported in 40 studies -1 published repeatedly- (UPD, studies = 30 n = 3072; their HCs, n = 2856; BPD, studies = 11 n = 393; their HCs, n = 540; with 1 study reporting on both UPD and BPD) included thiobarbituric acid reactive substances (TBARS), antioxidant uric acid and antioxidant-enhancing enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GPX). Compared with HCs, UPD and BPD were associated with significantly higher levels of TBARS, without differences between UPD and BPD (P = 0.11). Compared with HCs, UPD and BPD did not differ regarding the activity of the CAT (P = 0.28), SOD (P = 0.87) and GPX (P = 0.25) enzymes. However, uric acid levels were significantly higher vs HCs in BPD than in UPD among adult patients (P = 0.004). Results were heterogenous, which, for some parameters, decreased after stratification by the blood source (serum, plasma red blood cells, whole blood).

LIMITATIONS

The main limitations are the small number of studies/participants in the BPD subgroup, and heterogeneity of the results.

SUMMATIONS

Both BPD and UPD may be associated with an impaired oxidative stress balance, with significantly higher uric acid levels vs. HCs in UPD than in BPD.

Psychological status and serum uric acid levels in narcolepsy with type 1: A case-control study

BACKGROUND

The relationship between uric acid and patients with type 1 (NT1) remains unclear. UA may contribute to the development of depression. Depression is also common in NT1. Our study aimed to evaluate serum levels of UA, creatinine, and UA/Cr ratio, and examine the association of serum UA levels with psychological status in NT1 patients.

METHODS

This is a case-control study conducted on 48 patients diagnosed with NT1 and 40 healthy controls (HC). The 17-item Hamilton Depression Rating (HAMD-17) was used as screening tools for depressive symptoms for patients with NT1. Serum UA, creatinine, and UA/Cr ratio were measured. In addition, the correction of UA status and scores of depressive scales was statistically analyzed.

RESULTS

Approximately 70% of all subjects with NT1 had depression or depressive symptoms compared with the HC group, the serum UA levels and UA/Cr ratios were higher in patients with NT1 (p < 0.05). In addition, there was a negative correlation between UA levels and HAMD-17 scores in NT1 patients (r = -0.334; p = 0.020).

CONCLUSION

We found that serum UA levels were higher in patients with NT1, and the serum UA levels were negatively correlated with depressive symptom scores. Further well-designed prospective cohort studies are needed to determine the causality of the correlation and to further clarify the pathophysiological mechanisms of UA in NT1 patients.

Effects of forest bathing (shinrin-yoku) on serotonin in serum, depressive symptoms and subjective sleep quality in middle-aged males

BACKGROUND

We previously found that a forest bathing (shinrin-yoku) program significantly reduced the scores for depression, anxiety, anger, fatigue, and confusion and increased the score for vigor in the profile of mood states (POMS) test and showed a potential preventive effect on the depressive status in both males and females. In the present study, we investigated the effects of a forest bathing program on the level of serotonin in serum, depressive symptoms and subjective sleep quality in middle-aged males.

METHODS

Twenty healthy male subjects aged 57.3 ± 8.4 years were selected after obtaining informed consent. These subjects took day trips to a forest park, the birthplace of forest bathing in Japan named Akasawa Shizen Kyuyourin, Agematsu, Nagano Prefecture (situated in central Japan), and to an urban area of Nagano Prefecture as a control in June 2019. On both trips, they walked 2.5 km for 2 hours each in the morning and afternoon on Saturday and Sunday, respectively. Blood was sampled in the afternoon before and after each trip. Concentrations of serotonin and lactic acid in serum were measured. The POMS test and a questionnaire for subjective sleep quality were conducted before and after the trips. Ambient temperature and humidity were monitoring during the trips. The Ethics Committees of the Nippon Medical School and Nagano Prefectural Kiso Hospital approved this study.

RESULTS

The forest bathing program significantly increased level of serotonin in serum, and significantly increased the score for vigor and decreased the score for fatigue in the POMS test. The forest bathing program also improved the sleepiness on rising and feeling refreshed (recovery from fatigue) in the Oguri-Shirakawa-Azumi sleep inventory MA version (OSA-MA).

CONCLUSIONS

Taken together, the present study suggests that forest bathing may have potential preventive effects on depression (depressive status).

Association between serum uric acid and depressive symptoms stratified by low-grade inflammation status

Despite increasing evidence for an association between circulating uric acid (UA) and depression, the directionality of this association remains unclear and is potentially moderated by low-grade inflammation. Thus, the present study aimed to investigate the cross-sectional association between serum UA concentration and depressive symptoms in Korean individuals with and without low-grade inflammation, as measured using serum high-specific C-reactive protein (hs-CRP) levels. The final study sample comprised 4188 participants, aged 19–79 years, from the Korea National Health and Nutrition Examination Study 2016. Data on serum uric acid (UA) concentrations, serum hs-CRP levels, Patient Health Questionnaire-9 (PHQ-9) scores, and relative covariates were retrieved. Negative binomial regression with adjustment for the complex sample design was used to analyze the associations. After adjusting for covariates, log-transformed serum UA concentrations and total PHQ-9 scores were positively associated (incidence rate ratio [IRR] = 1.34 [95% confidence interval [CI] = 1.09–1.66]) for participants without low-grade inflammation and inversely associated (IRR = 0.64 [95% CI = 0.45–0.92]) for participants with low-grade inflammation. In conclusion, the direction of the association between serum UA and depressive symptoms was the opposite in participants with and without low-grade inflammation. The study has the limitation of potential uncontrolled confounders.

Therapy Management of Metabolic Disorder Comorbidity With Depression

Depression is a common disease that seriously endangers the physical and mental health of human beings, and it often coexists with other metabolic disorders such as diabetes and cancer. There have been endless reports on the mechanism, prevention, and cure of comorbidity because of its high incidence and poor prognosis and the increased burden on the family and society. There may be a specific comorbid basis and causal relationship between depression and metabolic diseases. Depression in patients with metabolic disorders can be effectively alleviated through psychotherapy and medication. The timely and effective treatment of depression can significantly improve the quality of life of patients with metabolic disorders, reduce their psychological burden, and promote the effective treatment of metabolic diseases. This study reorganized the research progress on the management of metabolic disorder comorbidity with depression.

Purinergic transmission in depressive disorders

Purinergic signaling involves the actions of purine nucleotides and nucleosides (such as adenosine) at P1 (adenosine), P2X, and P2Y receptors. Here, we present recent data contributing to a comprehensive overview of the association between purinergic signaling and depression. We start with background information on adenosine production and metabolism, followed by a detailed characterization of P1 and P2 receptors, with an emphasis on their expression and function in the brain as well as on their ligands. We provide data suggestive of altered metabolism of adenosine in depressed patients, which might be regarded as a disease biomarker. We then turn to considerable amount of preclinical/behavioral data obtained with the aid of the forced swim test, tail suspension test, learned helplessness model, or unpredictable chronic mild stress model and genetic activation/inactivation of P1 or P2 receptors as well as nonselective or selective ligands of P1 or P2 receptors. We also aimed to discuss the reason underlying discrepancies observed in such studies.

A cross-sectional study on the association of serum uric acid levels with depressive and anxiety symptoms in people with epilepsy

BACKGROUND

High serum uric acid (SUA) levels may provide protection against depression and anxiety through its defensive role in oxidative damage. The aim of this study was to test the hypothesis of the independent associations of lower SUA levels with depressive and anxiety symptoms among patients with epilepsy (PWE).

METHODS

A cross-sectional study was performed among 320 PWE aged ≥18 years old in Northeast China. The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E; Chinese version) and the Generalized Anxiety Disorder-7 scale (GAD-7; Chinese version) were used as screening tools for depressive and anxiety symptoms for PWE. Serum uric acid levels were measured. The associations of SUA levels with depressive and anxiety symptoms were assessed by using binary logistic regression models, with adjustment for the related risk factors (P< 0.05).

RESULTS

Lower SUA tertiles were significantly associated with higher C-NDDI-E and GAD-7 scores compared with the higher two tertiles (p=0.001, and p= 0.002). Patients with depressive symptoms exhibited significantly lower SUA levels compared to those without depressive symptoms (p< 0.001). SUA levels of patients with anxiety symptoms were significantly lower than those of patients without anxiety symptoms (p< 0.001). The first and second SUA tertiles were associated with depressive symptoms, with the third tertile group as the reference group, after adjusting for confounders (first tertile: OR = 4.694, 95% CI = 1.643~ 13.413, P = 0.004; second tertile: OR = 3.440, 95% CI = 1.278~9.256, P = 0.014). However, The first and second SUA tertiles were not associated with the risk of anxiety symptoms compared with the third tertile in the adjusted logistic regression model (First tertile: OR = 1.556, 95% CI = 0.699~3.464, P = 0.279; second tertile: OR = 1.265, 95% CI = 0.607~2.635, P = 0.530).

CONCLUSION

We found that lower SUA levels were independently associated with depressive symptoms but not with anxiety symptoms among PWE. Further well-designed prospective cohort studies are required to determine the causality of the associations and to further clarify the mechanisms of SUA in depressive symptoms.

Cyclooxygenase Inhibition Safety and Efficacy in Inflammation-Based Psychiatric Disorders

According to the World Health Organization, the major psychiatric and neurodevelopmental disorders include major depression, bipolar disorder, schizophrenia, and autism spectrum disorder. The potential role of inflammation in the onset and progression of these disorders is increasingly being studied. The use of non-steroidal anti-inflammatory drugs (NSAIDs), well-known cyclooxygenase (COX) inhibitors, combined with first-choice specific drugs have been long investigated. The adjunctive administration of COX inhibitors to classic clinical treatments seems to improve the prognosis of people who suffer from psychiatric disorders. In this review, a broad overview of the use of COX inhibitors in the treatment of inflammation-based psychiatric disorders is provided. For this purpose, a critical analysis of the use of COX inhibitors in the last ten years of clinical trials of the major psychiatric disorders was carried out.

Toll-Like Receptor Signaling in Depression

Depression is one of the most prevalent, disabling, and costly mental illnesses currently affecting over 300 million people worldwide. A subset of depressed patients display inflammation as indicated by increased levels of proinflammatory mediators in the blood and cerebrospinal fluid. Longitudinal and experimental studies suggest that this inflammatory profile may causally contribute to the initiation, maintenance, or recurrence of depressive episodes in the context of major depressive disorder (MDD). While the mechanistic pathways that mediate these depressogenic effects have not yet been fully elucidated, toll-like receptor (TLR) signaling is one potential common inflammatory pathway. In this review, we focus on the role that inflammation plays in depression, TLR signaling and its plasticity as a candidate pathway, its regulation by micro ribonucleic acids (miRNAs), and their potential as diagnostic biomarkers for identification of inflammatory subtypes of depression. Pre-clinical and clinical studies have demonstrated that TLR expression and TLR signaling regulators are associated with MDD. Further, TLR expression and signaling is in-turn, regulated in part by miRNAs and some TLR-responsive miRNAs indirectly modulate pathways that are implicated in MDD pathophysiology. These data suggest an intersection between TLR signaling regulation and MDD-linked pathways. While these studies suggest that miRNAs play a role in the pathophysiology of MDD via their regulatory effects on TLR pathways, the utility of miRNAs as biomarkers and potential treatment targets remains to be determined. Developing new and innovative techniques or adapting established immunological approaches to mental health, should be at the forefront in moving the field forward, especially in terms of categorization of inflammatory subtypes in MDD.

Course of depressive symptomatology and its association with serum uric acid in one-anastomosis gastric bypass patients

The changes in depressive symptomatology during the first year following one-anastomosis gastric bypass (OAGB) were evaluated and its association with uric acid (sUA). Fifty patients were included in this analysis. Beck Depression Inventory (BDI) for measuring depressive symptomatology, blood samples, and anthropometric measurements were assessed before (T0), at 6 (T6), and 12 months (T12) after surgery. There was a significant reduction in BDI total score at T6 (− 5.6 (95% CI − 2.1, − 9.1) points; p = 0.001) and at T12 (− 4.3 (95% CI − 0.9, − 7.9) points; p = 0.011). BMI loss was unrelated to depressive symptomatology. Patients with moderate to severe depressive symptomatology presented lower sUA levels than patients with none or minimal to mild (p = 0.028). ROC analysis revealed that sUA levels below 5.0 at T6 and 4.5 mg/dl at T12 had a prognostic accuracy for depression severity. Furthermore, delta sUA was significantly associated with delta BMI (β = 0.473; p = 0.012) and delta waist circumference (β = 0.531; p = 0.003). These findings support an improvement in depressive symptomatology in the first year postoperatively, however, without relation to BMI loss. Patients with moderate to severe depressive symptomatology presented with lower sUA levels over time. Therefore, sUA could be useful to predict moderate to severe depressive symptomatology in patients undergoing OAGB in clinical practice.

Association of serum uric acid levels with suicide risk in female patients with major depressive disorder: a comparative cross-sectional study

BACKGROUND

Individuals with major depressive disorder (MDD) have a high suicide risk. Some evidence suggests that uric acid (UA) may be involved in the pathophysiology of MDD. The purpose of this study was to evaluate whether serum UA levels were associated with suicide risk in MDD patients.

METHODS

One hundred four female patients with MDD (52 patients with suicide risk and 52 patients without suicide risk) and 52 healthy individuals were included in this study. The suicide risk was evaluated by Mini International Neuropsychiatric Interview (M.I.N.I.). Fasting serum levels of UA, as well as glucose, lipid and renal function indicators were measured.

RESULTS

Serum UA levels in MDD patients with suicide risk (245.01 ± 55.44 μmol/L) were significantly lower than those in MDD patients without suicide risk (274.17 ± 72.65 μmol/L) (p = 0.017) and healthy controls (271.42 ± 55.25 μmol/L) (p = 0.030). There was no difference in serum UA levels between the MDD patients without suicide risk and healthy controls (p = 0.821). Binary logistic regression analysis revealed a significant relationship between suicide risk and decreased serum UA levels (OR = 0.989, p = 0.010) in MDD patients.

CONCLUSION

Decreased serum UA levels were associated with suicide risk in MDD patients. Purinergic system dysfunction may be involved in the neurobiological basis of suicide risk in these patients.

Serum Metabonomic Study on the Antidepressant-like Effects of Ellagic Acid in a Chronic Unpredictable Mild Stress-Induced Mouse Model

As a polyphenol, ellagic acid (EA) has shown potential antidepressant activity. In this study, the effects and serum metabolomic analysis of EA against depression were investigated using a chronic unpredictable mild stress-induced (CUMS) model. EA (20 or 100 mg/kg body weight) significantly ameliorated the CUMS-induced depression-like behaviors, including reduced body weight, decreased sucrose preference, and increased immobility time in both the tail suspension test and the forced swimming test. Furthermore, EA attenuated the CUMS-induced hippocampal damage and significantly increased the brain-derived neurotrophic factor (BDNF) and the serotonin (5-HT) levels as well as suppressed the inflammatory response. The metabolomics analysis showed that the disturbance of glycerophospholipid (phosphatidylethanolamine and phosphatidylinositol), amino acid (l-arginine and N-stearoyl serine), and purine (uric acid) metabolism induced by CUMS was attenuated by the EA treatment. Furthermore, the correlation analysis indicated that the metabolite changes were strongly correlated with behavioral disorders, BDNF, 5-HT, and inflammatory cytokines levels. This study provided new insights for the antidepressant effects of EA and suggests that EA may be a potential nutraceutical for improving the management of depression.

Serum uric acid a depression biomarker

Objective

We aimed to investigate the difference in serum uric acid(SUA)levels between subtypes of depression and normal population, and whether SUA can be used to identify bipolar disorder depressive episode and major depressive disorder and predict the length of hospital stay.

Methods

1543 depression patients and 1515 healthy controls were obtained according to the entry and exclusion criteria from one mental health center of a tertiary hospital in southwestern China. The diagnosis and classification of depression was in accordance with ICD-10. The SUA value was derived from fasting plasma samples analysis. The level of SUA of all the participants was quantified using Roche cobas8000-c702-MSB automatic biochemical analyzer. Data were analyzed by SPSS18.0 statistical software package.

Results

Overall, the level of SUA in patients with depression was lower than that in normal control. Specifically, males’ SUA levels were in the interval of [240, 323.3) and [323.3, 406.6), and women were in the [160, 233.3] levels. The SUA level of bipolar disorder depressive episode was higher compared to major depressive disorder level. Interestingly, male patients who were hospitalized for two weeks had higher SUA than those who were hospitalized for three weeks or four weeks.

Conclusions

Our results suggest that the length of hospital stay may be associated with SUA, and when it is difficult to make a differential diagnosis of bipolar disorder depressive episode and major depressive disorder, the level of SUA may be considered. The adjustment of SUA as a method for treating depression needs to be carefully assessed.

Regulation of social behaviors by p-Stat3 via oxytocin and its receptor in the nucleus accumbens of male Brandt's voles (Lasiopodomys brandtii)

Social behavior plays a significant role in the formation of social structure and population regulation in both animals and humans. Oxytocin (OXT) and its receptor (OXTR) are well known for regulating social behaviors, but their upstream regulating factors are rarely investigated. We hypothesized that the phosphorylation of the signal transducer and activator of transcription 3 (p-Stat3) may regulate social and aggressive behaviors via the OXT system in the nucleus accumbens (NAc). To test this hypothesis, OXT, p-Stat3 inhibitor, OXTR antagonist, and OXT plus p-Stat3 inhibitor were infused, respectively, into the NAc in the brain of male Brandt's voles (Lasiopodomys brandtii) - a social rodent species in grassland of Inner Mongolia, China. Our data showed that blockage of p-Stat3-Tyr⁷⁰⁵ signaling pathway in the NAc not only increased aggressive behavior but also impaired social recognition of male Brandt's voles via its effects on the expression of local OXT and OXTR. These results have illustrated a novel signaling pathway of p-Stat3-Tyr⁷⁰⁵ in regulating social behaviors via the OXT system.

Chronic Food Antigen-specific IgG-mediated Hypersensitivity Reaction as A Risk Factor for Adolescent Depressive Disorder

Major depressive disorder (MDD) is the most common nonfatal disease burden worldwide. Systemic chronic low-grade inflammation has been reported to be associated with MDD progression by affecting monoaminergic and glutamatergic neurotransmission. However, whether various proinflammatory cytokines are abnormally elevated before the first episode of depression is still largely unclear. Here, we evaluated 184 adolescent patients who were experiencing their first episode of depressive disorder, and the same number of healthy individuals was included as controls. We tested the serum levels of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), IgE, 14 different types of food antigen-specific IgG, histamine, homocysteine, S100 calcium-binding protein B, and diamine oxidase. We were not able to find any significant differences in the serum levels of hs-CRP or TNF-α between the two groups. However, the histamine level of the patients (12.35 μM) was significantly higher than that of the controls (9.73 μM, P < 0.001, Mann–Whitney U test). Moreover, significantly higher serum food antigen-specific IgG positive rates were also found in the patient group. Furthermore, over 80% of patients exhibited prolonged food intolerance with elevated levels of serum histamine, leading to hyperpermeability of the blood–brain barrier, which has previously been implicated in the pathogenesis of MDD. Hence, prolonged high levels of serum histamine could be a risk factor for depressive disorders, and antihistamine release might represent a novel therapeutic strategy for depression treatment.

Childhood adversity, mental health, and oxidative stress: A pilot study

Childhood adversity is a potent risk factor for mental health conditions via disruptions to stress response systems. Dysregulations in oxidative stress systems have been associated with both childhood adversity and several psychological disorders (e.g., major depressive disorder) in adult populations. However, few studies have examined associations between childhood adversity, oxidative stress, and mental health in pediatric populations. Childhood adversity (Adverse Childhood Events [ACE]), oxidative stress [F2t-isoprostanes (IsoPs)], and mental health pathology were assessed in 50 adolescent females recruited primarily through the Department of Youth Services. Standard ordinary least squares regression models were run co-varying for age, race/ethnicity, adolescent nicotine use, study condition, and parent history of ACEs. Adolescents who reported experiencing four or more ACEs had significantly elevated IsoP levels. Further, internalizing symptom scores across diagnoses were significantly associated with elevated IsoPs, whereas no externalizing symptoms scores, except Attention Deficit Hyperactivity Disorder, were related to altered oxidative stress. Results indicate that IsoPs may be a global marker of childhood adversity and mental health symptomatology, particularly within internalizing symptom domains. A limitation is that body mass index was not collected for this sample. Future studies are needed to replicate and extend these findings in larger, more diverse samples.

Polyunsaturated fatty acids metabolism, purine metabolism and inosine as potential independent diagnostic biomarkers for major depressive disorder in children and adolescents

Major depressive disorder (MDD) in children and adolescents is a recurrent and disabling condition globally but its pathophysiology remains poorly elucidated and there are limited effective treatments available. We performed metabolic profiling of plasma samples based on ultra-high-performance liquid chromatography equipped with quadrupole time-offlight mass spectrometry to explore the potential biomarkers of depression in children and adolescents with MDD. We identified several perturbed pathways, including fatty acid metabolism-particularly the polyunsaturated fatty acids metabolism, and purine metabolism-that were associated with MDD in these young patients. In addition, inosine was shown as a potential independent diagnostic biomarker for MDD, achieving an area under the ROC curve of 0.999 in discriminating drug-naive MDD patients and 0.866 in discriminating drug-treated MDD from healthy controls. Moreover, we found evidence for differences in the pathophysiology of MDD in children and adolescents to that of adult MDD, specifically with tryptophan metabolism. Through metabolomic analysis, we have identified links between a framework of metabolic perturbations and the pathophysiology and diagnostic biomarker of child and adolescent MDD.

Depression and sterile inflammation: Essential role of danger associated molecular patterns

Stress is a major risk factor for psychiatric disorder including major depressive disorder (MDD) and can induce inflammation, which is known to be dysregulated in depression. Several clinical and pre-clinical studies have demonstrated a strong association between depressive symptoms and the expression of factors that increase inflammation. Conversely, administration of anti-inflammatory agents has been shown to ameliorate depressive symptoms, demonstrating the importance of inflammation as a mediator of depression. Although it is clear that inflammation plays a role in the pathophysiology of depression, the mechanism by which inflammation is activated in mood disorders remains unclear. To address this issue, studies have investigated the role of pattern recognition receptor (PRR) activation in stress-induced inflammation and mood disorders. However, the identification of the endogenous factors, referred to as danger-associated molecular patterns (DAMP) that activate these receptors remains understudied. Here we review the role of DAMPs in depression and highlight the clinical evidence for elevation of DAMP signaling in MDD patients and in pre-clinical animal stress models of depression.

Inflammation in psychiatric disorders: what comes first?

Neuropsychiatric disorders (i.e., mood disorders and schizophrenia) and inflammation are closely intertwined, and possibly powering each other in a bidirectional loop. Depression facilitates inflammatory reactions and inflammation promotes depression and other neuropsychiatric disorders. Patients with neuropsychiatric disorders exhibit all cardinal features of inflammation, including increased circulating levels of inflammatory inducers, activated sensors, and inflammatory mediators targeting all tissues. Inflammation may contribute to the pathophysiology and clinical progression of these disorders. Of note, proinflammatory cytokines modulate mood behavior and cognition by reducing brain monoamine levels, activating neuroendocrine responses, promoting excitotoxicity (increased glutamate levels), and impairing brain plasticity. What are the sources of this chronic inflammation? Increasing evidence indicates that changes in neuroendocrine regulation, metabolism, diet/microbiota, and negative health behaviors are important triggers of inflammation. Finally, recent data indicate that early-life stress is associated with overt inflammation prior to the development of neuropsychiatric disorders.

Association of gout and depression: A systematic review and meta-analysis

OBJECTIVE

Several studies have shown that gout is associated with depression symptoms. In this study, a systematic review and meta-analysis was performed to explore the relationship between gout and depression.

METHODS

Published articles were identified through a comprehensive review of PUBMED and EMBASE. Data from studies reporting relative risks, odds ratios, or hazard ratios comparing the risk of depression among participants who had gout versus those without gout were analyzed. A random-effect model was used to calculate pooled odds ratios and 95% confident intervals (CI).

RESULTS

Seven studies, which included 411 745 participants, aligned with our inclusion criteria and were included in the meta-analysis. Pooled analysis showed an association between gout and depression, with an odds ratio of 1.19 (95%CI, 1.11, 1.29; I²  = 60.2%). Subgroup-analysis adjusted (or not) by study type or study quality showed a statistically significant association of gout and depression in all subgroups. Sensitivity analysis by 1-study removed analysis, excluding articles of self-reported gout assessment or male-only, confirmed the robustness of our results.

CONCLUSION

Our meta-analysis demonstrates a positive association between gout and depression. Further large-scale prospective cohort studies are needed to investigate the causality between gout and depression.

Changes of serum uric acid and total bilirubin in elderly patients with major postischemic stroke depression

BACKGROUND

This was a longitudinal study which investigated the relationship between serum uric acid (SUA) and total bilirubin (Tbil) upon admission in elderly stroke patients and the occurrence of postischemic stroke depression (IPSD) at 3, 6, and 9 months of post-stroke follow-up.

SUBJECTS AND METHODS

Data were analyzed for 525 acute ischemic stroke patients. Beck Depression Inventory (BDI) scores >17 and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) were used separately to screen and diagnose IPSD at 3, 6, and 9 months post-stroke. Once IPSD was diagnosed, follow-up activities were terminated.

RESULTS

High levels of SUA (odds ratio [OR]=2.08, P<0.01) and Tbil (OR=2.31, P<0.01) in the first 3 months post-stroke and low levels of SUA (OR=2.05, P=0.03) and Tbil (OR=2.79, P<0.01) from 3 to 6 months post-stroke were identified as risk factors for major IPSD. At 3 months, patients with SUA levels ≥406.5 μmol/L (males with SUA levels of ≥409.5 μmol/L and females with SUA levels ≥385.5 μmol/L) and Tbil levels ≥23.65 μmol/L were more likely to develop major IPSD. At 6 months, both SUA (area under curve [AUC]=0.625, P=0.005, cutoff =194.0 μmol/L) and Tbil (AUC=0.681, P=0.004, cutoff =6.75 μmol/L) had minor diagnostic values (AUC<0.700), although SUA levels ≤214.5 μmol/L (AUC=0.756, P=0.001) in female patients had a good diagnostic value (AUC=0.722, P=0.006) for major IPSD. At 9 months, major IPSD showed no statistical relationship with either SUA (χ²=2.33, P=0.13) or Tbil (χ²=0.41, P=0.84).

CONCLUSION

Higher levels of SUA and Tbil on admission were closely related to the occurrence of major IPSD within 3 months of stroke. Lower levels of these two biomarkers on admission were characteristic for the occurrence of major IPSD between 3 and 6 months post-stroke, while 6 months after stroke, there was no relationship between major IPSD and these two biomarkers.

Association between the antioxidant uric acid and depression and antidepressant medication use in 96 989 individuals

OBJECTIVE

In the last decade, several studies have suggested that depression is accompanied by increased oxidative stress and decreased antioxidant defenses. We tested the hypothesis that high levels of the antioxidant uric acid are associated with lower risk of hospitalization with depression and use of prescription antidepressant medication.

METHOD

We examined plasma levels of the antioxidant uric acid in 96 989 individuals from two independent cohort studies. Logistic regression and Cox proportional hazards regression models were multivariable adjusted for age, gender, alcohol, smoking, income, body mass index, C-reactive protein, hemoglobin, triglycerides, cardiovascular disease, diabetes, and intake of meat and vegetables. Results were performed separately in each study and combined in a meta-analysis.

RESULTS

In both studies, high uric acid was associated with lower risk of hospitalization as in-patient or out-patient with depression and antidepressant medication use. A doubling in uric acid was associated with an effect estimate of 0.57 (95% CI 0.49-0.65) and 0.77 (0.73-0.81) for hospitalization with depression and antidepressant medication use. The association was consistent across strata of all covariates. Results were attenuated in Cox regression analyses with less statistical power.

CONCLUSION

High plasma levels of uric acid were associated with low risk of depression hospitalization and antidepressant medication use.

NLRP3 inflammasome-driven pathways in depression: Clinical and preclinical findings

Over the past three decades, an intricate interaction between immune activation, release of pro-inflammatory cytokines and changes in brain circuits related to mood and behavior has been described. Despite extensive efforts, questions regarding when inflammation becomes detrimental or how we can target the immune system to develop new therapeutic strategies for the treatment of psychiatric disorders remain unresolved. In this context, novel aspects of the neuroinflammatory process activated in response to stressful challenges have recently been documented in major depressive disorder (MDD). The Nod-like receptor pyrin containing 3 inflammasome (NLRP3) is an intracellular multiprotein complex responsible for a number of innate immune processes associated with infection, inflammation and autoimmunity. Recent data have demonstrated that NLRP3 activation appears to bridge the gap between immune activation and metabolic danger signals or stress exposure, which are key factors in the pathogenesis of psychiatric disorders. In this review, we discuss both preclinical and clinical evidence that links the assembly of the NLRP3 complex and the subsequent proteolysis and release of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18) in chronic stress models and patients with MDD. Importantly, we also focus on the therapeutic potential of targeting the NLRP3 inflammasome complex to improve stress resilience and depressive symptoms.

Uric acid excretion predicts increased aggression in urban adolescents

Elevated levels of uric acid have been linked with impulsive and disinhibited behavior in clinical and community populations of adults, but no studies have examined uric acid in relation to adolescent aggression. This study examined the prospective role of uric acid in aggressive behavior among urban, low income adolescents, and whether this relationship varies by gender. A total of 84 adolescents (M age 13.36years; 50% male; 95% African American) self-reported on their physical aggression at baseline and 1.5years later. At baseline, the youth also completed a 12-h (overnight) urine collection at home which was used to measure uric acid excretion. After adjusting for baseline aggression and age, greater uric acid excretion predicted more frequent aggressive behavior at follow up, with no significant gender differences. The results suggest that lowering uric acid levels may help reduce youth aggression.