Immunology of major depression

Peripheral mitochondrial DNA as a neuroinflammatory biomarker for major depressive disorder

In the pathogenesis of major depressive disorder, chronic stress-related neuroinflammation hinders favorable prognosis and antidepressant response. Mitochondrial DNA may be an inflammatory trigger, after its release from stress-induced dysfunctional central nervous system mitochondria into peripheral circulation. This evidence supports the potential use of peripheral mitochondrial DNA as a neuroinflammatory biomarker for the diagnosis and treatment of major depressive disorder. Herein, we critically review the neuroinflammation theory in major depressive disorder, providing compelling evidence that mitochondrial DNA release acts as a critical biological substrate, and that it constitutes the neuroinflammatory disease pathway. After its release, mitochondrial DNA can be carried in the exosomes and transported to extracellular spaces in the central nervous system and peripheral circulation. Detectable exosomes render encaged mitochondrial DNA relatively stable. This mitochondrial DNA in peripheral circulation can thus be directly detected in clinical practice. These characteristics illustrate the potential for mitochondrial DNA to serve as an innovative clinical biomarker and molecular treatment target for major depressive disorder. This review also highlights the future potential value of clinical applications combining mitochondrial DNA with a panel of other biomarkers, to improve diagnostic precision in major depressive disorder.

Using Data-Driven Algorithms with Large-Scale Plasma Proteomic Data to Discover Novel Biomarkers for Diagnosing Depression

Given recent technological advances in proteomics, it is now possible to quantify plasma proteomes in large cohorts of patients to screen for biomarkers and to guide the early diagnosis and treatment of depression. Here we used CatBoost machine learning to model and discover biomarkers of depression in UK Biobank data sets (depression n = 4,479, healthy control n = 19,821). CatBoost was employed for model construction, with Shapley Additive Explanations (SHAP) being utilized to interpret the resulting model. Model performance was corroborated through 5-fold cross-validation, and its diagnostic efficacy was evaluated based on the area under the receiver operating characteristic (AUC) curve. A total of 45 depression-related proteins were screened based on the top 20 important features output by the CatBoost model in six data sets. Of the nine diagnostic models for depression, the performance of the traditional risk factor model was improved after the addition of proteomic data, with the best model having an average AUC of 0.764 in the test sets. KEGG pathway analysis of 45 screened proteins showed that the most significant pathway involved was the cytokine-cytokine receptor interaction. It is feasible to explore diagnostic biomarkers of depression using data-driven machine learning methods and large-scale data sets, although the results require validation.

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.

Potential Plausible Role of Stem Cell for Treating Depressive Disorder: a Retrospective Review

Depression poses a significant threat to global physical and mental health, impacting around 3.8% of the population with a rising incidence. Current treatment options primarily involve medication and psychological support, yet their effectiveness remains limited, contributing to high relapse rates. There is an urgent need for innovative and more efficacious treatment modalities. Stem cell therapy, a promising avenue in regenerative medicine for a spectrum of neurodegenerative conditions, has recently garnered attention for its potential application in depression. While much of this work remains preclinical, it has demonstrated considerable promise. Identified mechanisms underlying the antidepressant effects of stem cell therapy encompass the stimulation of neurotrophic factors, immune function modulation, and augmented monoamine levels. Nonetheless, these pathways and other undiscovered mechanisms necessitate further investigation. Depression fundamentally manifests as a neurodegenerative disorder. Given stem cell therapy's success in addressing a range of neurodegenerative pathologies, it opens the door to explore its application in depression treatment. This exploration may include repairing damaged nerves directly or indirectly and inhibiting neurotoxicity. Nevertheless, significant challenges must be overcome before stem cell therapies can be applied clinically. Successful resolution of these issues will ultimately determine the feasibility of incorporating stem cell therapies into the clinical landscape. This narrative review provides insights into the progress of research, potential avenues for exploration, and the prevailing challenges in the implementation of stem cell therapy for treatment of depression.

Omics approaches open new horizons in major depressive disorder: from biomarkers to precision medicine

Major depressive disorder (MDD) is a recurrent episodic mood disorder that represents the third leading cause of disability worldwide. In MDD, several factors can simultaneously contribute to its development, which complicates its diagnosis. According to practical guidelines, antidepressants are the first-line treatment for moderate to severe major depressive episodes. Traditional treatment strategies often follow a one-size-fits-all approach, resulting in suboptimal outcomes for many patients who fail to experience a response or recovery and develop the so-called "therapy-resistant depression". The high biological and clinical inter-variability within patients and the lack of robust biomarkers hinder the finding of specific therapeutic targets, contributing to the high treatment failure rates. In this frame, precision medicine, a paradigm that tailors medical interventions to individual characteristics, would help allocate the most adequate and effective treatment for each patient while minimizing its side effects. In particular, multi-omic studies may unveil the intricate interplays between genetic predispositions and exposure to environmental factors through the study of epigenomics, transcriptomics, proteomics, metabolomics, gut microbiomics, and immunomics. The integration of the flow of multi-omic information into molecular pathways may produce better outcomes than the current psychopharmacological approach, which targets singular molecular factors mainly related to the monoamine systems, disregarding the complex network of our organism. The concept of system biomedicine involves the integration and analysis of enormous datasets generated with different technologies, creating a "patient fingerprint", which defines the underlying biological mechanisms of every patient. This review, centered on precision medicine, explores the integration of multi-omic approaches as clinical tools for prediction in MDD at a single-patient level. It investigates how combining the existing technologies used for diagnostic, stratification, prognostic, and treatment-response biomarkers discovery with artificial intelligence can improve the assessment and treatment of MDD.

The effect of a low-calorie diet on depressive symptoms in individuals with overweight or obesity: a systematic review and meta-analysis of interventional studies

BACKGROUND

Individuals with overweight or obesity are at a high risk for so-called 'atypical' or immunometabolic depression, with associated neurovegetative symptoms including overeating, fatigue, weight gain, and a poor metabolic profile evidenced e.g. by dyslipidemia or hyperglycemia. Research has generated preliminary evidence for a low-calorie diet (LCD) in reducing depressive symptoms. The aim of the current systematic review and meta-analysis is to examine this evidence to determine whether a LCD reduces depressive symptoms in people with overweight or obesity.

METHODS

Eligible studies were identified through PubMed, ISI Web of Science, and PsycINFO until August 2023. Standardized mean differences (SMDs) were derived using random-effects meta-analyses for (1) pre-post LCD comparisons of depression outcomes, and (2) LCD v. no-diet-control group comparisons of depression outcomes.

RESULTS

A total of 25 studies were included in the pre-post meta-analysis, finding that depression scores were significantly lower following a LCD (SMD = -0.47), which was not significantly moderated by the addition of exercise or behavioral therapy as a non-diet adjunct. Meta-regressions indicated that a higher baseline BMI and greater weight reduction were associated with a greater reduction in depression scores. The intervention-control meta-analysis (n = 4) found that overweight or obese participants adhering to a LCD showed a nominally lower depression score compared with those given no intervention (SMD = -0.29).

CONCLUSIONS

There is evidence that LCDs may reduce depressive symptoms in people with overweight or obesity in the short term. Future well-controlled intervention studies, including a non-active control group, and longer-term follow-ups, are warranted in order to make more definitive conclusions.

Jiao-tai-wan and its effective component-berberine improve diabetes and depressive disorder through the cAMP/PKA/CREB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao-tai-wan (JTW), a classic herbal formula of traditional Chinese medicine recorded in Han Shi Yi Tong, has been used to alleviate sleep disorders since ancient times. In modern pharmacological research, JTW has been adopted for treating diabetes mellitus and even exerts antidepressant effects. However, the potential mechanisms deserve further elucidation.

AIM OF THE STUDY

The prevalence of diabetes mellitus combined with depressive disorder (DD) is continuing to increase, yet it is currently under-recognized and its treatment remains inadequate. The present study aims to explore the underlying therapeutics and mechanisms of JTW on DD.

MATERIALS AND METHODS

Chronic restraint stress was used on db/db mice to construct a mouse model of DD. The therapeutic effects of JTW were assessed by glucolipid metabolic indexes, behavioral tests, and depression-related neurotransmitter levels. The inflammatory status and cell apoptosis of different mice were investigated and the changes in the cAMP/PKA/CREB pathway were detected. Combining the results of fingerprinting with molecular docking, the active components of JTW were screened. A cellular model was constructed by intervention of glucose combined with corticosterone (CORT). The levels of apoptosis and depression-related neurotransmitters in HT-22 cells were examined, and the changes in the cAMP/PKA/CREB pathway were tested. Finally, the activator and inhibitor of the PKA protein were used for reverse validation experiments.

RESULTS

JTW could improve the impaired glucose tolerance, lipid metabolism disorders, and depression-like symptoms in DD mice. Meanwhile, JTW could alleviate the inflammatory status, suppress the microglia activation, and improve hippocampal neuron apoptosis in DD mice. The dual effects of JTW might be associated with the activation of the cAMP/PKA/CREB pathway. Berberine (Ber) was identified for the in vitro experiment, it could reverse the apoptosis of HT-22 cells and up-regulate the depression-related neurotransmitter levels, and the effects of Ber were related to the activation of the cAMP/PKA/CREB pathway as well.

CONCLUSION

JTW could exert both hypoglycemic and antidepressant effects through activating the cAMP/PKA/CREB signaling pathway, its active component, Ber, could improve the damage to HT-22 cells induced by glucose combined with CORT via the activation of the cAMP/PKA/CREB pathway. Ber may be one of the effective components of the dual effects of JTW.

Which Factors Are Associated with Persistence of Depressive and Anxiety Symptoms in Patients Affected by Atopic Dermatitis despite 2-Year Treatment with Dupilumab?

Background: Atopic Dermatitis (AD) is a prevalent inflammatory skin disease whose course is often complicated by the presence of concomitant anxiety and depressive disorders. Dupilumab has been demonstrated to be largely effective in AD. The aims of the present study were to (1) to verify the effectiveness of 2-year dupilumab treatment on the depressive and anxiety symptoms of patients affected by AD and (2) to identify predictors of the persistence of psychiatric symptoms despite maintenance treatment with dupilumab. Methods: A total of 331 patients with severe AD were assessed at baseline and at different times over 2 years by a large set of rating scales, including the Eczema Area and Severity Index (EASI), the Hospital Anxiety and Depression Scale (HADS), and the Dermatology Life Quality Index (DLQI). Paired sample t-tests were performed to verify the effectiveness of dupilumab on the severity of AD and mental health items. Two binary logistic regression models were then used to identify the predictors of the persistence of clinically significant depression and anxiety, defined by a score ≥ 8 on each sub-scale of the HADS. Results: After 2 years of treatment with dupilumab, the patients benefited, showing a significant improvement in both the dermatological disease and comorbid depression/anxiety (p < 0.001 for all scales). Overall, 17.5% and 13% of patients, respectively, reported residual depressive and anxiety symptoms after the 2-year treatment with dupilumab. The baseline predictors of the persistence of clinically significant depressive symptoms after the 2-year treatment with dupilumab were found to be a higher body mass index (BMI) (p = 0.012), a lower impact of dermatological disease on quality of life (p = 0.015), and more severe depressive symptoms (p < 0.01), while for anxiety, the only predictor was found to be female gender (p = 0.03). Conclusions: Using a multidisciplinary approach, at baseline, dermatologists should more closely monitor patients who are at a greater risk of maintaining residual psychiatric symptoms despite therapy, such as those with more severe depressive symptoms and those who are overweight.

The association between lymphocyte to high-density lipoprotein ratio and depression: Data from NHANES 2015-2018

INTRODUCTION

The relationship of lymphocyte to high-density lipoprotein ratio (LHR) with depression remains uncertain. We aimed to evaluate the association between LHR and depression in US adults.

METHODS

In this cross-sectional study, a total of 4216 participants were enrolled from the National Health and Nutrition Examination Survey (2015-2018). Depressive symptoms were measured with the Patient Health Questionnaire-9 (PHQ-9). Participants were classified as having depression if PHQ-9 scores were ≥10. Multiple logistic regression models were used to explore the relationship between the LHR and depression.

RESULTS

Overall, the LHR was significantly associated with depression (per standard deviation increment; adjusted odds ratio (OR), 1.31; 95% confidence interval (CI) [1.14, 1.50]) after adjusted potential variables. Interactions between LHR with metabolic syndrome (MetS) and body mass index (BMI) on the risk of depression were found in stratified analysis (p for interaction < .05).

CONCLUSIONS

A higher level of LHR was significantly associated with higher odds of having depression in US adults, and it was strengthened in participants with MetS or BMI ranging from 25 to 30 kg/m2 .

Exploring the Roles of Vitamins C and D and Etifoxine in Combination with Citalopram in Depression/Anxiety Model: A Focus on ICAM-1, SIRT1 and Nitric Oxide

The study of intercellular adhesion molecule-1 (ICAM-1) and SIRT1, a member of the sirtuin family with nitric oxide (NO), is emerging in depression and anxiety. As with all antidepressants, the efficacy is delayed and inconsistent. Ascorbic acid (AA) and vitamin D (D) showed antidepressant properties, while etifoxine (Etx), a GABAA agonist, alleviates anxiety symptoms. The present study aimed to investigate the potential augmentation of citalopram using AA, D and Etx and related the antidepressant effect to brain and serum ICAM-1, SIRT1 and NO in an animal model. BALB/c mice were divided into naive, control, citalopram, citalopram + etx, citalopram + AA, citalopram + D and citalopram + etx + AA + D for 7 days. On the 8th day, the mice were restrained for 8 h, followed by a forced swim test and marble burying test before scarification. Whole-brain and serum expression of ICAM-1, Sirt1 and NO were determined. Citalopram's antidepressant and sedative effects were potentiated by ascorbic acid, vitamin D and etifoxine alone and in combination (p < 0.05), as shown by the decreased floating time and rearing frequency. Brain NO increased significantly (p < 0.05) in depression and anxiety and was associated with an ICAM-1 increase versus naive (p < 0.05) and a Sirt1 decrease (p < 0.05) versus naive. Both ICAM-1 and Sirt1 were modulated by antidepressants through a non-NO-dependent pathway. Serum NO expression was unrelated to serum ICAM-1 and Sirt1. Brain ICAM-1, Sirt1 and NO are implicated in depression and are modulated by antidepressants.

The Neurovascular Unit as a Locus of Injury in Low-Level Blast-Induced Neurotrauma

Blast-induced neurotrauma has received much attention over the past decade. Vascular injury occurs early following blast exposure. Indeed, in animal models that approximate human mild traumatic brain injury or subclinical blast exposure, vascular pathology can occur in the presence of a normal neuropil, suggesting that the vasculature is particularly vulnerable. Brain endothelial cells and their supporting glial and neuronal elements constitute a neurovascular unit (NVU). Blast injury disrupts gliovascular and neurovascular connections in addition to damaging endothelial cells, basal laminae, smooth muscle cells, and pericytes as well as causing extracellular matrix reorganization. Perivascular pathology becomes associated with phospho-tau accumulation and chronic perivascular inflammation. Disruption of the NVU should impact activity-dependent regulation of cerebral blood flow, blood-brain barrier permeability, and glymphatic flow. Here, we review work in an animal model of low-level blast injury that we have been studying for over a decade. We review work supporting the NVU as a locus of low-level blast injury. We integrate our findings with those from other laboratories studying similar models that collectively suggest that damage to astrocytes and other perivascular cells as well as chronic immune activation play a role in the persistent neurobehavioral changes that follow blast injury.

NEDD4 Like E3 Ubiquitin Protein Ligase Represses Astrocyte Activation and Aggravates Neuroinflammation in Mice with Depression via Paired Box 6 Ubiquitination

Astrocytes are implicated in stress-induced neuroinflammatory responses in depression. This paper was to explore the molecular mechanism of the E3 ubiquitin ligase NEDD4L (NEDD4 like E3 ubiquitin protein ligase) in depressed mice by regulating astrocyte activation, and to find a new target for depression. A mouse model of depression was established by CUMS (chronic mild unpredictable stress) in 48 6-week male C57BL/6 mice and injected with sh-NEDD4L vector for testing behavioral and cognitive abilities, histopathological changes, and the number of GFAP-positive cells. The mRNA and protein levels of NEDD4L, PAX6 (paired box 6) and P2X7R (purinergic ligand-gated ion channel 7 receptor) were measured. Inflammation model was established by lipopolysaccharide treatment of mouse astrocyte line C8-D1A and infected with sh-NEDD4L. After CUMS induction, mice showed depression-like symptoms, increased inflammatory infiltration, decreased glial fibrillary acidic protein (GFAP)-positive cells in brain tissue, and increased NEDD4L protein levels. NEDD4L inhibition increased GFAP-positive cells, increased PAX6 protein levels and decreased P2X7R mRNA and protein levels, and decreased inflammatory factor secretion in brain tissue and in vitro cells. PAX6 knockdown or P2X7R overexpression partially reversed the effects of NEDD4L inhibition on astrocyte activation and neuroinflammation. To conclude, highly-expressed NEDD4L in depression-like mouse brain inhibits astrocyte activation and exacerbates neuroinflammation by ubiquitinating PAX6 and promoting P2X7R level.

Treatment of ankylosing spondylitis with TNFα inhibitors does not affect serum levels of tryptophan metabolites

The imbalance between the kynurenine and serotonin pathways can have serious consequences, e.g., depression. One of the factors leading to the imbalance between the pathways of tryptophan metabolism is inflammation. The aim of our study was to assess the impact of treatment with tumor necrosis factor-alpha (TNFα)-inhibitors on tryptophan metabolism in patients with ankylosing spondylitis (AS). Forty patients with AS (twenty-eight males, twelve females; mean age 40 ± 11 years), qualified to receive anti-TNF-α treatment, were prospectively assessed. As a control group, 20 healthy volunteers (7 males and 13 females, mean age 38 ± 5 years) were recruited from the general population. Patients underwent full clinical and biochemical assessment before and after 6 months of therapy. Disease activity was assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The presence of depressive disorders was assessed with Beck's Depression Inventory (BDI) scale. Serum concentrations of tryptophan, serotonin, kynurenine, and quinolinic acid were measured. The predominance of the kynurenine pathway in AS patients (compared to the control group) was demonstrated (p < 0.001). Surprisingly, no significant changes in serum levels of tryptophan and its metabolites in AS patients after treatment were found, despite clinical improvement. Moreover, the components of tryptophan metabolism did not correlate significantly with the clinical activity of AS, depression nor laboratory inflammatory markers. Probably some other factors influence the pathways of tryptophan metabolism in patients with ankylosing spondylitis.

Apigenin attenuates depressive-like behavior via modulating monoamine oxidase A enzyme activity in chronically stressed mice

Chronic stress is a risk factor for depression and is characterized by elevated levels of brain monoamine oxidase A (MAOA). Mounting evidence has shown that MAOA is a biochemical link between stress and depression. Apigenin (API), a natural flavonoid, as demonstrated in vitro inhibitory effect on MAOA, is suggestive of antidepressant-like activity. However, the in vivo inhibitory effect of API on MAOA and how it affects depression still remain unclear. Here, we report the probable mechanisms of action of API in chronic unpredictable mild stress (CUMS)-induced depression in mice. Treatment with API reversed anhedonia, and reduced anxiety and immobility time in behavioral studies. API reduced brain corticosterone and malondialdehyde (MDA) levels but increased brain levels of glutathione and superoxide dismutase. Furthermore, interleukin-6 and tumor necrosis factor-α were attenuated by API. It also restored cell loss and inhibited the activity of MAOA in the hippocampal brain regions and prefrontal cortex. Comparative binding affinity of API for MAOA (-7.7 kcal/mol) through molecular docking studies was greater than that of reference compound, clorgyline (-6.8 kcal/mol). Favorable hydrophobic interactions important to API binding at MAOA binding cavity was revealed to include conventional hydrogen bond (Cys323 and Tyr444), π-Sulfur (Cys323), π-π Stacked (Tyr407), π-π T-shaped (Phe208), π-lone pair and π-alkyl (Ile335, Ile180) interactions. These results suggest that API is a potent, selective, reversible inhibitor of MAOA with capability of attenuating CUMS-induced depression via inhibiting MAOA enzyme activity and altering other pathomechanisms.

Time Perspective as a Mediator of Depressive Symptoms in Patients with Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) is a chronic endocrinopathy characterized by oligo- or anovulation, clinical and/or biochemical markers of hyperandrogenism, and polycystic ovaries, and it is associated with an increased prevalence of depression. Research conducted on psychiatric patients has shown correlations between depression and decreased cognitive function. The aim of this study was to examine the possible mediation of the time perspective (TP) in the development of depressive symptoms in patients with PCOS. Methods: A study was conducted on 83 patients with PCOS and 65 healthy women. Standardized questionnaires were used to assess depressive symptoms (Beck Depression Inventory—BDI-II) and time perspective (Zimbardo Time Perspective Inventory—ZTPI). Results: Our study revealed an indirect influence of depressive symptoms on PCOS through the positive future time perspective. In the logistic regression model, which included depression and a given time perspective as predictors of PCOS, only the future TP (β = −0.004, p < 0.003, OR = 1.004, 95% CI [1.001, 1.008]) was significantly independently related to the occurrence of PCOS. Conclusions: Our result is another argument for the role of psychoeducation and appropriate communication with a patient from the risk group in a way that builds hope and allows to regain influence on life situation.

The roles of extracellular vesicles in major depressive disorder

Major depressive disorder (MDD) is a serious mental disease characterized by depressed mood, loss of interest and suicidal ideation. Its rising prevalence has rendered MDD one of the largest contributors to the global disease burden. However, its pathophysiological mechanism is still unclear, and reliable biomarkers are lacking. Extracellular vesicles (EVs) are widely considered important mediators of intercellular communication, playing an important role in many physiological and pathological processes. Most preclinical studies focus on the related proteins and microRNAs in EVs, which can regulate energy metabolism, neurogenesis, neuro-inflammation and other pathophysiological processes in the development of MDD. The purpose of this review is to describe the current research progress of EVs in MDD and highlight their potential roles as biomarkers, therapeutic indicators and drug delivery carriers for the treatment of MDD.

Identification and investigation of depression-related molecular subtypes in inflammatory bowel disease and the anti-inflammatory mechanisms of paroxetine

Background

Up to 40 per cent of people with active inflammatory bowel disease (IBD) also suffer from mood disorders such as anxiety and depression. Notwithstanding, the fundamental biological pathways driving depression in IBD remain unknown.

Methods

We identified 33 core genes that drive depression in IBD patients and performed consensus molecular subtyping with the NMF algorithm in IBD. The CIBERSORT were employed to quantify the immune cells. Metabolic signature was characterized using the "IOBR" R package. The scoring system (D. score) based on PCA. Pre-clinical models are constructed using DSS.

Results

Using transcriptome data from the GEO database of 630 IBD patients, we performed a thorough analysis of the correlation between IBD and depression in this research. Firstly, the samples were separated into two different molecular subtypes (D. cluster1 and D. cluster2) based on their biological signatures. Moreover, the immunological and metabolic differences between them were evaluated, and we discovered that D. cluster2 most closely resembled IBD patients concomitant with depression. We also developed a scoring system to assess the IBD-related depression and predict clinical response to anti-TNF- therapy, with a higher D. score suggesting more inflammation and worse reaction to biological therapies. Ultimately, we also identified through animal experiments an antidepressant, paroxetine, has the added benefit of lowering intestinal inflammation by controlling microorganisms in the digestive tract.

Conclusions

This study highlights that IBD patients with or without depression show significant variations and antidepressant paroxetine may help reduce intestinal inflammation.

Early Life Stress, Neuroinflammation, and Psychiatric Illness of Adulthood

Stress exposure during early stages of life elevates the risk of developing psychopathologies and psychiatric illness in later life. The brain and immune system are not completely developed by birth and therefore continue develop after birth; this post birth development is influenced by several psychosocial factors; hence, early life stress (ELS) exposure can alter brain structural development and function. A growing number of experimental animal and observational human studies have investigated the link between ELS exposure and increased risk of psychopathology through alternations in the immune system, by evaluating inflammation biomarkers. Recent studies, including brain imaging, have also shed light on the mechanisms by which both the innate and adaptive immune systems interact with neural circuits and neurotransmitters, which affect psychopathology. Herein, we discuss the link between the experience of stress in early life and lifelong alterations in the immune system, which subsequently lead to the development of various psychiatric illnesses.

The Role of Inflammation in the Pathophysiology of Depression and Suicidal Behavior: Implications for Treatment

Depression and suicidal behavior are 2 complex psychiatric conditions of significant public health concerns due to their debilitating nature. The need to enhance contemporary treatments and preventative approaches for these illnesses not only calls for distillation of current views on their pathogenesis but also provides an impetus for further elucidation of their novel etiological determinants. In this regard, inflammation has recently been recognized as a potentially important contributor to the development of depression and suicidal behavior. This review highlights key evidence that supports the presence of dysregulated neurometabolic and immunologic signaling and abnormal interaction with microbial species as putative etiological hallmarks of inflammation in depression as well as their contribution to the development of suicidal behavior. Furthermore, therapeutic insights addressing candidate mechanisms of pathological inflammation in these disorders are proposed.

Serum cytokine variations among inpatients with major depression, bipolar disorder, and schizophrenia versus healthy controls: a prospective 'true-to-life' study

BACKGROUND

There is increasing evidence of the association between chronic low-grade inflammation and severe mental illness (SMI). The objective of our study was to assess serum cytokine levels (SCLs) at admission and discharge in a true-to-life-setting population of inpatients with major depression (MD), bipolar disorder (BD), and schizophrenia (Sz), as well as of healthy controls.

METHODS

We considered MD, BD, and Sz to be SMIs. We evaluated 206 inpatients [MD, N = 92; BD, N = 26; mania (Ma), N = 44; Sz, N = 44). Generalized estimating equations were used to analyze variations in SCL [interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-2, IL-4, IL-6, IL-10, and IL-17] at hospital admission and discharge. Results of 100 healthy controls were compared with those of SMI patients at both time points. We evaluated patients' improvement during in-hospital treatment in terms of general psychiatric symptoms, global clinical impression, functionality, and manic and depressive symptoms with validated scales.

RESULTS

In all, 68.9% of patients completed the study. Overall, SMI inpatients had higher SCL when compared with controls regardless of diagnosis. There was a significant decrease in Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression-Severity Scale (CGI-S) scores, and an increase in Global Assessment of Functioning (GAF) scores for all disorders evaluated (p < 0.001), as well as a significant decrease in HDRS-17 scores among MD inpatients (p < 0.001) and in YMRS scores among Ma inpatients (p < 0.001). IL-2 and IL-6 levels decreased significantly between admission and discharge only among MD inpatients (p = 0.002 and p = 0.03, respectively). We found no further statistically significant changes in SCL among the remaining disorders (BD, Ma, and Sz). There was no significant decrease in IFN-γ (p = 0.64), TNF-α (p = 0.87), IL-4 (p = 0.21), IL-10 (p = 0.88), and IL-17 (p = 0.71) levels in any of the evaluated diagnoses.

CONCLUSION

MD inpatients had a decrease in IL-2 and IL-6 levels during hospitalization, which was accompanied by clinical improvement. No associations were found for the remaining SMIs (BD, Ma, and Sz).

Night shift hormone: How does melatonin affect depression?

Melatonin is the main hormone secreted by the pineal gland that modulates the circadian rhythm and mood. Previous studies have shown the therapeutic effects of melatonin, or its important analogue, agomelatine, on depression. In this review study, we aimed to discuss the potential mechanisms of melatonin involved in the treatment of depression. It was noted that disrupted circadian rhythm can lead to depressive state, and melatonin via regulating circadian rhythm shows a therapeutic effect. It was also noted that melatonin induces antidepressant effects via promoting antioxidant system and neurogenesis, and suppressing oxidative stress, neuroinflammation, and apoptosis. The interaction effect between melatonin or agomelatine and serotonergic signaling has a significant effect on depression. It was noted that the psychotropic effects of agomelatine are induced by the synergistic interaction between melatonin and 5-HT_2C receptors. Agomelatine also interacts with glutamatergic signaling in brain regions involved in regulating mood and circadian rhythm. Interestingly, it was concluded that melatonin exerts both pro- and anti-inflammatory effects, depending on the grade of inflammation. It was suggested that synergistic interaction between melatonin and 5-HT_2C receptors may be able to induce therapeutic effects on other psychiatric disorders. Furthermore, dualistic role of melatonin in regulating inflammation is an important point that can be examined at different levels of inflammation in animal models of depression.

Traditional herbal formula Jiao-tai-wan improves chronic restrain stress-induced depression-like behaviors in mice

OBJECTIVES

Jiao-tai-wan (JTW) has been often used to treat insomnia and diabetes mellitus. Recent studies found its antidepressant activity, but the related mechanism is not clear. This study is to evaluate the therapeutic effects of JTW on chronic restraint stress (CRS)-induced depression mice and explore the potential mechanisms.

METHODS

CRS was used to set up a depression model. Mice in different groups were treated with 0.9 % saline, JTW and fluoxetine. After the last day of CRS, the behavioral tests were conducted. The levels of neurotransmitters, inflammatory cytokines and HPA axis index were detected and the protein expressions of NLRP3 inflammasome complex were determined. H&E, NISSL, TUNEL and immunofluorescence staining were used to observe histopathological changes and the activation of microglia and astrocytes. The potential mechanisms were explored via network pharmacology and verified by Western blot.

RESULTS

The assessment of liver and kidney function showed that JTW was non-toxic. Behavioral tests proved that JTW can effectively ameliorate depression-like symptoms in CRS mice, which may be related to the inhibition of NLRP3 inflammasome activation. JTW can also improve the inflammatory state and HPA axis hyperactivity in mice, and has a protective effect on CRS-induced hippocampal neurons damage. The network pharmacology analysis and the results of Western blot suggested that the antidepressant effects of JTW may be related to the MAPK signaling pathway.

CONCLUSION

Our findings indicated that JTW may exert antidepressant effects in CRS-induced mice by inhibiting NLRP3 inflammasome activation and improving inflammatory state, and MAPK signaling pathway may also be involved.

Microglial Inflammatory-Metabolic Pathways and Their Potential Therapeutic Implication in Major Depressive Disorder

Increasing evidence supports the notion that neuroinflammation plays a critical role in the etiology of major depressive disorder (MDD), at least in a subset of patients. By virtue of their capacity to transform into reactive states in response to inflammatory insults, microglia, the brain's resident immune cells, play a pivotal role in the induction of neuroinflammation. Experimental studies have demonstrated the ability of microglia to recognize pathogens or damaged cells, leading to the activation of a cytotoxic response that exacerbates damage to brain cells. However, microglia display a wide range of responses to injury and may also promote resolution stages of inflammation and tissue regeneration. MDD has been associated with chronic priming of microglia. Recent studies suggest that altered microglial morphology and function, caused either by intense inflammatory activation or by senescence, may contribute to depression and associated impairments in neuroplasticity. In this context, modifying microglia phenotype by tuning inflammatory pathways might have important translational relevance to harness neuroinflammation in MDD. Interestingly, it was recently shown that different microglial phenotypes are associated with distinct metabolic pathways and analysis of the underlying molecular mechanisms points to an instrumental role for energy metabolism in shaping microglial functions. Here, we review various canonical pro-inflammatory, anti-inflammatory and metabolic pathways in microglia that may provide new therapeutic opportunities to control neuroinflammation in brain disorders, with a strong focus on MDD.

The Lesson from the First Italian Lockdown: Impacts on Anxiety and Depressive Symptoms and Sleep Quality in Patients with Remission of Inflammatory Bowel Disease

BACKGROUND

During the COVID-19 pandemic in Italy, decisions were taken to adopt restrictive legislative measures, such as the first half of the 2020 lockdown. In those months, patients with inflammatory bowel disease experienced social isolation and reduced access to health care.

OBJECTIVE

We aimed to evaluate, in this condition, the presence of remission subgroups that were most impacted by the lockdown.

METHODS

During the first Italian lockdown, we recruited patients with remission of inflammatory bowel disease by administering an online questionnaire including patient demographics, the Beck Anxiety Questionnaire Inventory, the Beck Depression Inventory questionnaire, and the Pittsburg Sleep Quality Index, all validated standardized questionnaires for anxiety symptom levels, depression, and sleep quality.

RESULTS

Our results showed how female patients (p<0.0001) with Crohn's disease (p<0.001) experienced worse levels of anxiety symptoms. Female patients (p<0.0001) between 50 and 60 years of age (p=0.013) with Crohn's disease (p=0.047) experienced worse levels of depressive symptoms. Females also experienced significantly worse sleep levels (p<0.001). We found a correlation between the number of sleeping hours (p<0.001) and the time taken to fall asleep (p<0.001) and the Beck Anxiety Questionnaire Inventory,which showed a linear worsening of the number of minutes it took to fall asleep, and the Beck Depression Inventory questionnaire.

CONCLUSION

Among patients with remission of inflammatory bowel disease, female patients, patients with Crohn's disease, and people aged between 50 and 70 years should be considered for screening for anxiety and depression disorders and an assessment of sleep quality.

Associations between Melatonin, Neuroinflammation, and Brain Alterations in Depression

Pro-inflammatory systemic conditions that can cause neuroinflammation and subsequent alterations in brain regions involved in emotional regulation have been suggested as an underlying mechanism for the pathophysiology of major depressive disorder (MDD). A prominent feature of MDD is disruption of circadian rhythms, of which melatonin is considered a key moderator, and alterations in the melatonin system have been implicated in MDD. Melatonin is involved in immune system regulation and has been shown to possess anti-inflammatory properties in inflammatory conditions, through both immunological and non-immunological actions. Melatonin has been suggested as a highly cytoprotective and neuroprotective substance and shown to stimulate all stages of neuroplasticity in animal models. The ability of melatonin to suppress inflammatory responses through immunological and non-immunological actions, thus influencing neuroinflammation and neurotoxicity, along with subsequent alterations in brain regions that are implicated in depression, can be demonstrated by the antidepressant-like effects of melatonin. Further studies that investigate the associations between melatonin, immune markers, and alterations in the brain structure and function in patients with depression could identify potential MDD biomarkers.

Update on Statin Treatment in Patients with Neuropsychiatric Disorders

Statins are widely accepted as first-choice agents for the prevention of lipid-related cardiovascular diseases. These drugs have both anti-inflammatory and anti-oxidant properties, which may also make them effective as potential treatment marked by perturbations in these pathways, such as some neuropsychiatric disorders. In this narrative review, we have investigated the effects of statin therapy in individuals suffering from major depressive disorder (MDD), schizophrenia, anxiety, obsessive-compulsive disorder (OCD), bipolar disorder (BD), delirium, and autism spectrum disorders using a broad online search of electronic databases. We also explored the adverse effects of these drugs to obtain insights into the benefits and risks associated with their use in the treatment of these disorders. Lipophilic statins (including simvastatin) because of better brain penetrance may have greater protective effects against MDD and schizophrenia. The significant positive effects of statins in the treatment of anxiety disorders without any serious adverse side effects were shown in numerous studies. In OCD, BD, and delirium, limitations, and contradictions in the available data make it difficult to draw conclusions on any positive effect of statins. The positive effects of simvastatin in autism disorders have been evaluated in only a small number of clinical trials. Although some studies showed positive effect of statins in some neuropsychiatric disorders, further prospective studies are needed to confirm this and define the most effective doses and treatment durations.

Prenatal ambient air pollution and maternal depression at 12 months postpartum in the MADRES pregnancy cohort

BACKGROUND

Depression is the leading cause of mental health-related morbidity and affects twice as many women as men. Hispanic/Latina women in the US have unique risk factors for depression and they have lower utilization of mental health care services. Identifying modifiable risk factors for maternal depression, such as ambient air pollution, is an urgent public health priority. We aimed to determine whether prenatal exposure to ambient air pollutants was associated with maternal depression at 12 months after childbirth.

METHODS

One hundred eighty predominantly low-income Hispanic/Latina women participating in the ongoing MADRES cohort study in Los Angeles, CA were followed from early pregnancy through 12 months postpartum through a series of phone questionnaires and in-person study visits. Daily prenatal ambient pollutant estimates of nitrogen dioxide (NO2), ozone (O3), and particulate matter (PM10 and PM2.5) were assigned to participant residences using inverse-distance squared spatial interpolation from ambient monitoring data. Exposures were averaged for each trimester and across pregnancy. The primary outcome measure was maternal depression at 12 months postpartum, as reported on the 20-item Center for Epidemiologic Studies-Depression (CES-D) scale. We classified each participant as depressed (n = 29) or not depressed (n = 151) based on the suggested cutoff of 16 or above (possible scores range from 0 to 60) and fitted logistic regression models, adjusting for potential confounders.

RESULTS

We found over a two-fold increased odds of depression at 12 months postpartum associated with second trimester NO2 exposure (OR = 2.63, 95% CI: 1.41-4.89) and pregnancy average NO2 (OR = 2.04, 95% CI: 1.13-3.69). Higher second trimester PM2.5 exposure also was associated with increased depression at 12 months postpartum (OR = 1.56, 95% CI: 1.01-2.42). The effect for second trimester PM10 was similar and was borderline significant (OR = 1.58, 95% CI: 0.97-2.56).

CONCLUSIONS

In a low-income cohort consisting of primarily Hispanic/Latina women in urban Los Angeles, we found that prenatal ambient air pollution, especially mid-pregnancy NO2 and PM2.5, increased the risk of depression at 12 months after childbirth. These results underscore the need to better understand the contribution of modifiable environmental risk factors during potentially critical exposure periods.

White Matter Alterations Associated with Pro-inflammatory Cytokines in Patients with Major Depressive Disorder

Objective

Regarding the neuroinflammatory theory of major depressive disorder (MDD), little is known about the effect of pro-inflammatory cytokines on white matter (WM) changes in MDD. We aimed to investigate the relationship between pro-inflammatory cytokines and WM alterations in patients with MDD.

Methods

Twenty-two patients with MDD and 22 healthy controls (HC) were evaluated for brain imaging and pro-inflammatory cytokines including interleukin (IL)-1β, IL-6, IL-8, interferon-γ and tumor necrosis factor (TNF)-α. Tract-based spatial statistics and FreeSurfer were used for brain image analysis.

Results

The levels of TNF-α and IL-8 were significantly higher in the MDD group than in HC. Compared to HC, lower fractional anisotropy (FA), and higher median diffusivity (MD) and radial diffusivity (RD) values were found in the MDD group for several WM regions. Voxel-wise correlation analysis showed that the level of TNF-α was negatively correlated with FA, and positively correlated with MD and RD in the left body and genu of the corpus callosum, left anterior corona radiata, and left superior corona radiata.

Conclusion

Our findings suggest that TNF-α may play an important role in the WM alterations in depression, possibly through demyelination.

Targeting NLRP3 Inflammasome in Translational Treatment of Nervous System Diseases: An Update

Neuroinflammatory response is the immune response mechanism of the innate immune system of the central nervous system. Both primary and secondary injury can activate neuroinflammatory response. Among them, the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays a key role in the inflammatory response of the central system. Inflammasome is a type of pattern recognition receptor, a cytoplasmic polyprotein complex composed of members of the Nod-like receptor (NLR) family and members of the pyrin and HIN domain (PYHIN) family, which can be affected by a variety of pathogen-related molecular patterns or damage-related molecular patterns are activated. As one of the research hotspots in the field of medical research in recent years, there are increasing researches on immune function abnormalities in the onset of neurological diseases such as depression, AD, ischemic brain injury and cerebral infarction, the NLRP3 inflammasome causes the activated caspase-1 to cleave pre-interleukin-1β and pre-interleukin-18 into mature interleukin-1β and interleukin-18, in turn, a large number of inflammatory factors are produced, which participate in the occurrence and development of the above-mentioned diseases. Targeted inhibition of the activation of inflammasomes can reduce the inflammatory response, promote the survival of nerve cells, and achieve neuroprotective effects. This article reviews NLRP3 inflammasome's role in neurological diseases and related regulatory mechanisms, which providing references for future research in this field.

Transcranial low-level laser therapy in an in vivo model of stroke: Relevance to the brain infarct, microglia activation and neuroinflammation

Stroke is the main cause of death and functional disability. The available therapy affects only 5% of patients, and new therapeutic approaches have been constantly tested. Transcranial photobiomodulation (PBM) is promising for its neuroprotective effect on brain injuries. Thus, the present study investigated the PBM effects in an in vivo model of ischemic stroke induced by photothrombosis (PT). Five different groups of Wistar rats were submitted or not to a daily dose of fish oil or/and laser sessions for 2 months. The ischemia volume was evaluated by stereology; GFAP, Iba and NeuN by immunohistochemistry; TNF-α, IL-1β, IL-6, IL-10 and TGF-β by ELISA assay. PBM influenced both the lesion volume and the GFAP. Furthermore, PBM and Ω-3 or both reduced Iba RNAm. PBM reduced TNF-α, IL-1β, IL-6, brain damage, neuroinflammation and microglial activation, and it increased astroglial activity in peri-lesioned region after stroke.

Personality classification enhances blood metabolome analysis and biotyping for major depressive disorders: two-species investigation

BACKGROUND

The relationship between depression and personality has long been suggested, however, biomarker investigations for depression have mostly overlooked this connection.

METHODS

We collected personality traits from 100 drug-free patients with major depressive disorders (MDD) and 100 healthy controls based on the Five-Factor Model (FFM) such as Neuroticism (N) and Extraversion (E), and also obtained 63 plasma metabolites profiles by LCMS-based metabolome analysis.

RESULTS

Partitional clustering analysis using the NEO-FFI data classified all subjects into three major clusters. Eighty-six subjects belonging to Cluster 1 (C1: less personality-biased group) constituted half of MDD patients and half of healthy controls. C2 constituted 50 subjects mainly MDD patients (N ^high + E ^low), and C3 constituted 64 subjects mainly healthy subjects (N ^low + E ^high). Using metabolome information, the machine learning model was optimized to discriminate MDD patients from healthy controls among all subjects and C1, respectively. The performance of the model for all subjects was moderate (AUC = 0. 715), while the performance was extremely improved when limited to C1 (AUC = 0. 907). Tryptophan-pathway plasma metabolites including tryptophan, serotonin and kynurenine were significantly lower in MDD patients especially among C1. We also validated metabolomic findings using a social-defeat mice model of stress-induced depression.

LIMITATIONS

A case-control study design and sample size is not large.

CONCLUSIONS

Our results suggest that personality classification enhances blood biomarker analysis for MDD patients and further translational investigations should be conducted to clarify the biological relationship between personality traits, stress and depression.

Efficacy of Sertraline Plus Placebo or Add-On Celecoxib in Major Depressive Disorder: Macrophage Migration Inhibitory Factor as a Promising Biomarker for Remission After Sertraline-Results From a Randomized Controlled Clinical Trial

Introduction: Previous research delivers strong indications that inflammatory activation leads to treatment resistance in a subgroup of patients with Major Depressive Disorder (MDD). Thus, tailored interventions are needed. The present study aimed to find potential biomarkers that may enable patients to be stratified according to immune activation. Methods: A phase IIa randomized placebo-controlled trial was performed to assess levels of inflammatory compounds in responders/remitters and non-responders/non-remitters to sertraline plus celecoxib (n = 20) and sertraline plus placebo (n = 23). Levels of macrophage migration inhibitory factor, neopterin, and tumor necrosis factor alpha were determined by enzyme-linked immunosorbent assay; response and remission were measured by reduction of the Montgomery Åsberg Depression Rating Scale score. Results: Both treatment groups showed a significant decline in depression symptoms, but no difference was found between groups. A clear pattern emerged only for macrophage migration inhibitory factor: placebo remitters showed significantly lower baseline levels than non-remitters (a similar trend was seen in responders and non-responders) while celecoxib responders showed a trend for higher baseline levels than non-responders. Conclusion: Small subsample sizes are a notable limitation, wherefore results are preliminary. However, the present study provides novel insights by suggesting macrophage migration inhibitory factor as a promising biomarker for treatment choice. The trial was registered in EU Clinical Trials Register (EU-CTR): https://www.clinicaltrialsregister.eu/ctr-search/trial/2009-011990-34/DE, EudraCT-No.: 2009-011990-34.

[Neopterin as a potential biomarker in neuropsychiatry]

The importance of finding predictors or biomarkers of neuropsychiatric pathology, as well as methods of its prevention, treatment and early diagnosis is beyond question. The level of neopterin in body fluids is one of the possible biomarkers. Increased levels of neopterin in biological fluids (e.g., serum, cerebrospinal fluid or urine) are closely associated with various diseases associated with cellular immune response. The data presented in the review indicate the relevance of the study of neopterin concentrations in body fluids in patients with mental illness for the development of diagnostic and prognostic tests or as a pharmacodynamic marker of drug action.

Tryptophan Metabolism and Related Pathways in Psychoneuroimmunology: The Impact of Nutrition and Lifestyle

In the past, accelerated tryptophan breakdown was considered to be a feature of clinical conditions, such as infection, inflammation, and malignant disease. More recently, however, the focus has changed to include the additional modulation of tryptophan metabolism by changes in nutrition and microbiota composition. The regulation of tryptophan concentration is critical for the maintenance of systemic homeostasis because it integrates essential pathways involved in nutrient sensing, metabolic stress response, and immunity. In addition to tryptophan being important as a precursor for the synthesis of the neurotransmitter serotonin, several catabolites along the kynurenine axis are neuroactive. This emphasizes the importance of the immunometabolic fate of this amino acid for processes relevant to neuropsychiatric symptoms. In humans, besides hepatic catabolism, there is usually a strong relationship between immune activation-associated tryptophan breakdown and increased levels of biomarkers, such as neopterin, which has particular relevance for both acute and chronic diseases. A shift towards neopterin synthesis during oxidative stress may indicate a corresponding decrease in tetrahydrobiopterin, a cofactor of several mono-oxygenases, providing a further link between tryptophan metabolism and serotonergic and catecholaminergic neurotransmission. The psychoneuroimmunological consequences of tryptophan metabolism and the susceptibility of this pathway to modulation by a variety of nutritional and lifestyle-related factors have important implications for the development of both diagnostic and treatment options.

Obstetric complications and subsequent risk of mood disorders for offspring in adulthood: a comprehensive overview

Background: A number of studies reported obstetric complications (OCs) to be a risk factor for the development of psychiatric conditions in the adulthood, including mood disorders.Aim: The aim of this study was to review the literature about the link between OCs during the perinatal period (items of Lewis-Murray scale) and the future risk of developing a mood disorder in adulthood, such as the major depressive disorder (MDD) or the bipolar disorder (BD).Methods: A research in the main database sources has been conducted to obtain an overview of the association mentioned above.Results: Few studies have investigated the role of OCs in the development of mood disorders in adulthood. The most robust evidence is that low birth weight (LBW) and preterm birth may be risk factors for the development of MDD in the future, even if some of the available data come from studies with small sample sizes or a retrospective design.Conclusion: OCs may confer a risk of developing mood disorders in adulthood. Future research should confirm these preliminary findings and clarify if other obstetric or neonatal complications (e.g. cyanosis or newborn epileptic seizures) may have a role in the future onset of mood disorders.

Emotional Impairments and Neuroinflammation are Induced in Male Mice Invulnerable to Repeated Social Defeat Stress

Prolonged stress triggers neuroinflammation, which plays a significant role in the development of depression; however, stressed people do not always suffer from depression because of individual differences in stress vulnerability. Negative cognitive bias (NCB) toward pessimistic judgment often underlies depressive episodes. However, a relationship between stress vulnerability, neuroinflammation, and NCB remains elusive. In addition, an animal model with all the traits would be a powerful tool for studying the etiology of depression and its therapeutic approaches. Accordingly, this study evaluated the effect of stress vulnerability on neuroinflammation and depression-related behaviors, including NCB in males, using a modified version of repeated social defeat stress (mRSDS) paradigm, a validated animal model of psychosocial stress. Exposure to mRSDS, consisting of 5 min of social defeat by unfamiliar CD-1 aggressor mice for five consecutive days, caused NCB, which co-occurred with depressive- and anxiety-like behaviors, and neuroinflammation in male BALB/c mice. Treatment with minocycline, an antibiotic with anti-inflammatory property, blocked mRSDS-induced depressive-like behaviors and neuroinflammation, but not NCB, indicating the limited effect of an anti-inflammatory intervention. In addition, marked differences were found in neuroinflammatory profiles and hippocampal gene expression patterns between resilient and unstressed mice, as well as between susceptible and resilient mice. Therefore, mice resilient to mRSDS are indeed not intact. Our findings provide insights into the unique features of the mRSDS model in male BALB/c mice, which could be used to investigate the etiological mechanisms underlying depression as well as bridge the gap in the relationship between stress vulnerability, neuroinflammation, and NCB in males.

Meta-analysis of total and differential white blood cell counts in schizophrenia

OBJECTIVE

Schizophrenia is associated with alterations in blood inflammatory markers, including cytokines. Total white blood cell (WBC) count is a marker of low-grade inflammation. We conducted a meta-analysis of total and differential WBC counts in patients with schizophrenia.

METHOD

Articles were identified through a systematic search of PsycINFO, Pub Med, Web of Science, and the associated references. Data were analyzed using a random effects approach.

RESULTS

Twenty-four studies met the inclusion criteria. Blood total WBC, monocytes, and neutrophils were significantly higher in schizophrenia vs. controls with small-to-medium effect sizes (standardized mean difference [SMD] = 0.39-0.53, P < 0.01 for each). In first-episode psychosis compared with controls, neutrophils and monocytes were significantly increased with similar effect sizes (SMD = 0.40-0.41, P ≤ 0.01 for each), and there was a trend for higher total WBC (SMD = 0.46, P = 0.05).

CONCLUSIONS

Consistent with studies of other inflammatory markers, we found evidence for increased total and differential WBC counts in schizophrenia. Our results complement other studies of WBC counts in schizophrenia. These findings are relevant to the pathophysiology and potentially the treatment of schizophrenia.

The Bidirectional Relationship of Depression and Inflammation: Double Trouble

Depression represents the number one cause of disability worldwide and is often fatal. Inflammatory processes have been implicated in the pathophysiology of depression. It is now well established that dysregulation of both the innate and adaptive immune systems occur in depressed patients and hinder favorable prognosis, including antidepressant responses. In this review, we describe how the immune system regulates mood and the potential causes of the dysregulated inflammatory responses in depressed patients. However, the proportion of never-treated major depressive disorder (MDD) patients who exhibit inflammation remains to be clarified, as the heterogeneity in inflammation findings may stem in part from examining MDD patients with varied interventions. Inflammation is likely a critical disease modifier, promoting susceptibility to depression. Controlling inflammation might provide an overall therapeutic benefit, regardless of whether it is secondary to early life trauma, a more acute stress response, microbiome alterations, a genetic diathesis, or a combination of these and other factors.

The clock-controlled chemokine contributes to neuroinflammation-induced depression

The circadian rhythm plays a central role in immune function, and its disruption has been closely linked to the etiology of depression. However, the mechanisms underlying the association between depression and circadian rhythm remain unclear. We found that mice deficient of Per2, a central clock component of circadian output, were resilient to neuroinflammation-induced depressive behavior. After repeated central lipopolysaccharide (LPS) injections, MCP-1, MIP-1β, and RANTES increased in wild type (WT) but not in Per2-deficient mice. In addition, intracerebroventricular injection of RANTES resulted in depression-like behavior, and Met-RANTES, a CCR5 antagonist, could reverse depression-like behavior induced by LPS treatments. These results indicated that the Per2 gene contributes to depression via chemokines, especially RANTES. Furthermore, BMAL1 expression decreased in LPS-treated Per2-deficient mice and BMAL1 could bind to the promoter of Rantes, indicating clock gene can act as a regulator for neuroinflammation. In conclusion, Rantes, a clock-controlled gene (CCG), is involved in clock-immunological mechanisms underlying the effects of Per2 on neuroinflammation-induced depression-like behavior.

The cellular and molecular basis of major depressive disorder: towards a unified model for understanding clinical depression

Major depressive disorder (MDD) is considered a serious public health issue that adversely impacts an individual's quality of life and contributes significantly to the global burden of disease. The clinical heterogeneity that exists among patients limits the ability of MDD to be accurately diagnosed and currently, a symptom-based approach is utilized in many cases. Due to the complex nature of this disorder, and lack of precise knowledge regarding the pathophysiology, effective management is challenging. The aetiology and pathophysiology of MDD remain largely unknown given the complex genetic and environmental interactions that are involved. Nonetheless, the aetiology and pathophysiology of MDD have been the subject of extensive research, and there is a vast body of literature that exists. Here we overview the key hypotheses that have been proposed for the neurobiology of MDD and highlight the need for a unified model, as many of these pathways are integrated. Key pathways discussed include neurotransmission, neuroinflammation, clock gene machinery pathways, oxidative stress, role of neurotrophins, stress response pathways, the endocannabinoid and endovanilloid systems, and the endogenous opioid system. We also describe the current management of MDD, and emerging novel therapies, with particular focus on patients with treatment-resistant depression (TRD).

How acute and chronic physical disease may influence mental health - An Analysis of neurotransmitter precursor amino acid levels

Patients with somatic diseases are more likely to develop depression than physically healthy individuals, and comorbid depression has been shown to incrementally worsen patients´ health. Physical conditions are known to influence neurotransmitter precursor amino acids, changes in which are associated with depressive symptoms. In this prospective study we investigated neurotransmitter precursor amino acids levels in patients with acute and chronic physical disease and evaluated their association with depressive symptoms. 177 subjects with and without chronic medical comorbidity (factor: chronic physical disease) admitted to the trauma and orthopaedic surgery ward for a surgical intervention (factor: acute physical disease) were included in the analysis. Chronic medical comorbidity was scored using Charlson Index and depressive and anxiety symptoms using the Hospital Anxiety and Depression Scale (HADS, factor: mental health). The effect of covariates was also evaluated. C-reactive protein (CRP), neopterin, kynurenine/tryptophan (KYN/TRP) and phenylalanine/tyrosine (PHE/TYR) were analysed by HPLC or ELISA prior to surgery and at discharge. Mixed Model as well as correlation analyses were performed. CRP and neopterin levels were influenced by the factors "acute physical disease" (both p < 0.001) and "chronic physical disease" (p = 0.024, p = 0.001 respectively). PHE/TYR, an index of the catecholamine pathway) was related to the factors "acute physical disease" (p < 0.001) and "mental health-depression" (p = 0.012), while KYN/TRP (an index of the kynurenine pathway affecting also serotonin) was associated with "chronic physical disease" (p = 0.005). No significant effect of "mental health-anxiety" was found. The effect of "mental health-depression" on PHE/TYR was more pronounced in females (gender p = 0.003). Differences in HADS depression values correlated with changes in PHE/TYR and both correlated with CRP values. In conclusion, inflammatory reactions related to acute or chronic physical conditions can influence the availability of neurotransmitter precursor amino acids l and these changes are associated with mental health.

Relationships of Non-coding RNA with diabetes and depression

In order to study the molecular differences between type 2 diabetes mellitus (T2DM) and T2DM with depression (DD), we aimed to screen the differential expression of lncRNA, mRNA, and circRNA in the blood of patients with T2DM and DD. Based on the self-rating depression scale (SDS), patient health questionnaire 9 (PHQ9), blood glucose and HbA1c, we divided the patients into T2DM and DD group. Peripheral blood was collected from the two groups of patients to perform lncRNA, mRNA, and circRNA expression profiling and screening DD-related specific molecules. Subsequently, bioinformatics analysis was performed to investigate the functions of differentially expressed genes (DEgenes). Finally, RT-PCR and lncRNA-mRNA regulatory network was performed to verify the expressions of lncRNAs and mRNAs related to the occurrence and development of DD. 28 lncRNAs, 107 circRNAs, and 89 mRNAs were identified in DD differential expression profiles. GO and pathway analysis found that 20 biological process (BP) related entities and 20 pathways associated with DD. The analysis shows that the genes that are differentially expressed in the DD group involved in the development of the neuropsychiatric system, immunity, and inflammation. Then, we screening for the important DElncRNA and mRNA associated with DD were verified by RT-PCR experiments and the results of RT-PCR were consistent with the sequencing results. LncRNA, circRNA, and mRNA differential expression profiles exist in DD patients compared with T2DM. The lncRNA-mRNA regulatory network analysis confirmed the crosslinking and complex regulation patterns of lncRNA and mRNA expression and verified the authenticity of the regulatory network.

Differential Neuroinflammatory Response in Male and Female Mice: A Role for BDNF

A growing body of evidence supports the close relationship between major depressive disorder (MDD), a severe psychiatric disease more common among women than men, and alterations of the immune/inflammatory system. However, despite the large number of studies aimed at understanding the molecular bases of this association, a lack of information exists on the potential cross-talk between systems known to be involved in depression and components of the inflammatory response, especially with respect to sex differences. Brain-derived neurotrophic factor (BDNF) is a neurotrophin with a well-established role in MDD etiopathology: it is altered in depressed patients as well as in animal models of the disease and its changes are restored by antidepressant drugs. Interestingly, this neurotrophin is also involved in the inflammatory response. Indeed, it can be secreted by microglia, the primary innate immune cells in the central nervous system whose functions may be in turn regulated by BDNF. With these premises, in this study, we investigated the reciprocal impact of BDNF and the immune system by evaluating the neuroinflammatory response in male and female BDNF-heterozygous mutant mice acutely treated with the cytokine-inducer lipopolysaccharide (LPS). Specifically, we assessed the potential onset of an LPS-induced sickness behavior as well as changes of inflammatory mediators in the mouse hippocampus and frontal cortex, with respect to both genotype and sex. We found that the increased inflammatory response induced by LPS in the brain of male mice was independent of the genotype, whereas in the female, it was restricted to the heterozygous mice with no changes in the wild-type group, suggestive of a role for BDNF in the sex-dependent effect of the inflammatory challenge. Considering the involvement of both BDNF and neuroinflammation in several psychiatric diseases and the diverse incidence of such pathologies in males and females, a deeper investigation of the mechanisms underlying their interaction may have a critical translational relevance.

Social Defeat Modulates T Helper Cell Percentages in Stress Susceptible and Resilient Mice

Altered adaptive immunity involving T lymphocytes has been found in depressed patients and in stress-induced depression-like behavior in animal models. Peripheral T cells play important roles in homeostasis and function of the central nervous system and thus modulate behavior. However, the T cell phenotype and function associated with susceptibility and resilience to depression remain largely unknown. Here, we characterized splenic T cells in susceptible and resilient mice after 10 days of social defeat stress (SDS). We found equally decreased T cell frequencies and comparably altered expression levels of genes associated with T helper (Th) cell function in resilient and susceptible mice. Interleukin (IL)-17 producing CD4⁺ and CD8⁺ T cell numbers in the spleen were significantly increased in susceptible mice. These animals further exhibited significantly reduced numbers of regulatory T cells (T_reg) and decreased gene expression levels of TGF-β. Mice with enhanced Th17 differentiation induced by conditional deletion of PPARγ in CD4⁺ cells (CD4-PPARγ^KO), an inhibitor of Th17 development, were equally susceptible to SDS when compared to CD4-PPARγ^WT controls. These data indicate that enhanced Th17 differentiation alone does not alter stress vulnerability. Thus, SDS promotes Th17 cell and suppresses T_reg cell differentiation predominantly in susceptible mice with yet unknown effects in immune responses after stress exposure.

Inflammatory markers are altered in severe mental disorders independent of comorbid cardiometabolic disease risk factors

BACKGROUND

Inflammation and immune activation have been implicated in the pathogenesis of severe mental disorders and cardiovascular disease (CVD). Despite high level of comorbidity, many studies of the immune system in severe mental disorders have not systematically taken cardiometabolic risk factors into account.

METHODS

We investigated if inflammatory markers were increased in schizophrenia (SCZ) and affective (AFF) disorders independently of comorbid CVD risk factors. Cardiometabolic risk factors (blood lipids, body mass index and glucose) and CVD-related inflammatory markers CXCL16, soluble interleukin-2 receptor (sIL-2R), soluble CD14 (sCD14), macrophage inhibitory factor and activated leukocyte cell adhesion molecule (ALCAM) were measured in n = 992 patients (SCZ, AFF), and n = 647 healthy controls. We analyzed the inflammatory markers before and after controlling for comorbid cardiometabolic risk factors, and tested for association with psychotropic medication and symptom levels.

RESULTS

CXCL16 (p = 0.03) and sIL-2R (p = 7.8 × 10-5) were higher, while sCD14 (p = 0.05) were lower in patients compared to controls after controlling for confounders, with significant differences in SCZ for CXCL16 (p = 0.04) and sIL-2R (p = 1.1 × 10-5). After adjustment for cardiometabolic risk factors higher levels of sIL-2R (p = 0.001) and lower sCD14 (p = 0.002) remained, also in SCZ (sIL-2R, p = 3.0 × 10-4 and sCD14, p = 0.01). The adjustment revealed lower ALCAM levels (p = 0.03) in patients. We found no significant associations with psychotropic medication or symptom levels.

CONCLUSION

The results indicate that inflammation, in particular enhanced T cell activation and impaired monocyte activation, are associated with severe mental disorders independent of comorbid cardiometabolic risk factors. This suggests a role of novel pathophysiological mechanisms in severe mental disorders, particularly SCZ.

Relationship of traumatic brain injury to chronic mental health problems and dementia in military veterans

Traumatic brain injury (TBI) is an unfortunately common event in military life. The conflicts in Iraq and Afghanistan have increased public awareness of TBI in the military. Certain injury mechanisms are relatively unique to the military, the most prominent being blast exposure. Blast-related mild TBI (mTBI) has been of particular concern in the most recent veterans although controversy remains concerning separation of the postconcussion syndrome associated with mTBI from post-traumatic stress disorder. TBI is also a risk factor for the development of neurodegenerative diseases including chronic traumatic encephalopathy (CTE) and Alzheimer's disease (AD). AD, TBI, and CTE are all associated with chronic inflammation. Genome wide association studies (GWAS) have identified multiple genetic loci associated with AD that implicate inflammation and - in particular microglia - as key modulators of the AD- and TBI-related degenerative processes. At the molecular level, recent studies have identified TREM2 and TYROBP/DAP12 as components of a key molecular hub linking inflammation and microglia to the pathophysiology of AD and possibly TBI. Evidence concerning the relationship of TBI to chronic mental health problems and dementia is reviewed in the context of its relevance to military veterans.

Serotonin Expression in Lichen Planus Lesions and Its Relationship with Depression/Anxiety

Background

Psychological factors such as stress, depression, and anxiety have been documented to contribute to the development of lesions in lichen planus (LP).

Objective

To evaluate the relationship between serotonin expression in LP lesions and depression/anxiety.

Methods

Forty patients (22 females, 18 males) with LP and 20 healthy control subjects were included in this study. The severity of LP was assessed with the palmar method (using the measurement of affected body surface area [BSA]). The depression and anxiety scores were measured with Beck's depression inventory (BDI) and Beck's anxiety inventory (BAI). The expression of serotonin was determined via immunohistochemistry in LP lesions and in the control group skin using a monoclonal antibody to serotonin.

Results

The skin biopsies of the LP patients had significantly higher levels of serotonin than those of the control subjects (p<0.001). In the LP patients, and there was a positive correlation between serotonin expression and LP severity (p=0.022). Based on the results from the BDI and BAI, there was a significant relationship between the severity of depression/anxiety and intensity of serotonin expression (p<0.001).

Conclusion

Data from this study suggest that serotonin may have a possible role in the pathogenesis of LP. Further, the relationship between serotonin expression in acute cutaneous lesions and the depression/anxiety scores indicates that serotonin may be a mediator for the association of LP and depression/anxiety simultaneously. There is a need for more specific studies showing the expression of serotonin in the lichen planus to demonstrate the cause or effect.

Neuroinflammation and aberrant hippocampal plasticity in a mouse model of emotional stress evoked by exposure to ultrasound of alternating frequencies

Emotional stress is a form of stress evoked by processing negative mental experience rather than an organic or physical disturbance and is a frequent cause of neuropsychiatric pathologies, including depression. Susceptibility to emotional stress is commonly regarded as a human-specific trait that is challenging to model in other species. Recently, we showed that a 3-week-long exposure to ultrasound of unpredictable alternating frequencies within the ranges of 20-25 kHz and 25-45 kHz can induce depression-like characteristics in laboratory mice and rats. In an anti-depressant sensitive manner, exposure decreases sucrose preference, elevates behavioural despair, increases aggression, and alters serotonin-related gene expression. To further investigate this paradigm, we studied depression/distress-associated markers of neuroinflammation, neuroplasticity, oxidative stress and the activity of glycogen synthase kinase-3 (GSK-3) isoforms in the hippocampus of male mice. Stressed mice exhibited a decreased density of Ki67-positive and DCX-positive cells in the subgranular zone of hippocampus, and altered expression of brain-derived neurotrophic factor (BDNF), its receptor TrkB, and anti-apoptotic protein kinase B phosphorylated at serine 473 (AktpSer473). The mice also exhibited increased densities of Iba-1-positive cells, increased oxidative stress, increased levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) in the hippocampus and plasma, and elevated activity of GSK-3 isoforms. Together, the results of our investigation have revealed that unpredictable alternating ultrasound evokes behavioural and molecular changes that are characteristic of the depressive syndrome and validates this new and simple method of modeling emotional stress in rodents.