The inflammatory & neurodegenerative (I&ND) hypothesis of depression: leads for future research and new drug developments in depression

The potential neuroprotective effect of empagliflozin against depressive-like behavior induced by chronic unpredictable mild stress in rats: Involvement of NLRP3 inflammasome

Depression is a prevalent and debilitating condition that has a severe negative impact on a person's life. Chronic stress exposure plays a substantial role in the development of depression. In the present study, rats were exposed to chronic unpredictable mild stress (CUMS) for four weeks. Empagliflozin (EMPA), a Sodium-Glucose Cotransporter-2 (SGLT-2) inhibitor, is an oral antidiabetic agent exhibiting antioxidant, anti-inflammatory, and antiapoptotic effects. This study aimed to examine the antidepressant effect of EMPA in an experimental animal model of depression induced by CUMS in rats and explore the probable underlying mechanisms. Rats were treated with EMPA, per-orally, at a dose of 10 mg/kg/day for four weeks. EMPA treatment counteracted CUMS-induced histopathological, biochemical and behavioral alterations. EMPA suppressed the CUMS-induced increase in the oxidative stress, inflammatory, and apoptotic markers, where levels of MDA, IL-1β, TNF-α, NF-κB, NLRP3 and active caspase 3 were reduced by 29.6 %, 24.8 %, 17.9 %, 36.6 %, 24.5 % and 41.5 %, respectively, compared to the disease group. Furthermore, EMPA decreased the level of the microglial activation marker, iba-1 by 24 % in comparison to the disease group. In addition, EMPA treatment decreased blood glucose levels by 39 %, decreased serum insulin levels by 60.6 %, decreased HOMA-IR by 76.5 % and increased GLUT 4 expression, compared to the CUMS group, all which proves that EMPA has an effect insulin signaling and alleviates insulin resistance. Our results conclude that modulating key factors involved in depression, such as inflammation, oxidative stress, and NLRP3 inflammasome pathway, accounts for the anti-depressant effect of EMPA.

Microglial phagocytosis and regulatory mechanisms: Key players in the pathophysiology of depression

Depression is a globally prevalent emotional disorder with a complex pathophysiology. Microglia are resident immune cells in the central nervous system, playing crucial roles in regulating inflammation, synaptic plasticity, immune phagocytosis, and other functions, thereby exerting significant impacts on neuropsychiatric disorders like depression. Increasing research indicates that abnormal phagocytic function of microglia in the brain is involved in depression, showing excessive or insufficient phagocytosis in different states. Here, we have provided a review of the signaling molecules involved in microglial phagocytosis in depression, including "eat me" signals such as phosphatidylserine (PS), complement, and "don't eat me" signals such as CD47, CD200 and related receptors. Furthermore, we discuss the regulatory effects of existing pharmaceuticals and dietary nutrients on microglial phagocytosis in depression, emphasizing the need for tailored modulation based on the varying phagocytic states of microglia. This review aims to facilitate a deeper understanding of the role of microglial phagocytosis in depression and provide a roadmap for potential therapeutic strategies for depression targeting microglial phagocytosis.

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.

Association between depressive symptoms and mortality in patients with Cardiovascular-Kidney-Metabolic syndrome: The mediating role of inflammatory biomarkers

BACKGROUND

The objective of this investigation was to explore the correlation between depressive symptoms and mortality in individuals with different stages of Cardiovascular-Kidney-Metabolic syndrome, and to examine how inflammatory markers mediate this association.

METHODS

The study included 12,314 participants derived from the National Health and Nutrition Examination Survey (NHANES) 2005-2018. The association between depressive symptoms and mortality was examined across different stages of CKM using weight-based Cox regression analysis and restricted cubic spline (RCS) regression. A mediation analysis was conducted to assess effects of inflammatory markers on this correlation.

RESULTS

After fully adjusting for potential confounders, participants with moderate to severe depression, compared to those with no depression, were correlated with higher mortality, including CKM stage 1 (hazard ratio[HR], 2.20 [95 % CI, 1.33, 3.64]), CKM stage 2 (HR, 1.75 [95 % CI, 1.18, 2.60]), and CKM stage 3 (HR, 2.34 [95 % CI, 1.12, 4.87]). In CKM stage 4, a higher PHQ-9 score (≥10) was not significantly linked to higher mortality (HR, 1.07 [95 % CI, 0.69, 1.64]). A positive linear correlation between the PHQ-9 score and all-cause mortality was revealed by the RCS regression analyses. The systemic inflammation response index (SIRI) and neutrophil count accounted for 12.0 % and 6.0 %, respectively, of the associations between depressive symptoms and mortality.

CONCLUSION

In this cohort study, depressive symptoms were significantly correlated with increased all-cause mortality among participants with CKM stages 1 to 3. Therefore, enhancing mental health monitoring and intervention can improve the long-term survival of individuals with CKM stages 1 to 3.

Plasma neurofilament light chain mediates the effect of subsyndromal symptomatic depression on cognitive decline in older adults

Objective

Subsyndromal symptomatic depression (SSD) is associated with an increased risk of cognitive impairment in non-demented older adults. However, the mechanism underlying this relationship remains unclear. This study aimed to investigate whether plasma neurofilament light chain (NfL) mediates the relationship between SSD and cognitive decline.

Materials and methods

Data of 707 non-demented older adults from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort were analyzed. Geriatric Depression Scale (GDS) scores were collected at baseline, while plasma NfL levels and cognitive assessments were obtained at baseline, 1-year, and 2-year follow-up visits. SSD was defined as a GDS score of 1-5. Mediation analyses were performed to examine whether the rate of change in plasma NfL levels mediated the relationship between SSD and cognitive decline.

Results

Participants with SSD exhibited a greater increase in plasma NfL levels and more pronounced declines in global cognition, memory, executive function, language, and processing speed over 2 years compared to non-SSD participants. The rate of change in plasma NfL levels significantly mediated the relationship between SSD and accelerated cognitive decline, particularly in global cognition, memory, language, and processing speed.

Conclusion

Plasma NfL, which is related to neuroaxonal damage, may partially mediate the association between SSD and accelerated cognitive decline in non-demented older adults. These findings suggest that dynamic changes in plasma NfL levels may reflect early neurobiological alterations associated with SSD and could help identify individuals at increased risk of cognitive deterioration over a 2-year period.

Study on the comorbid mechanisms of sarcopenia and late-life depression

The increasing global aging population has brought greater focus to age-related diseases, particularly muscle-brain comorbidities such as sarcopenia and late-life depression. Sarcopenia, defined by the gradual loss of muscle mass and function, is notably prevalent among older individuals, while late-life depression profoundly affects their mental health and overall well-being. Epidemiological evidence suggests a high co-occurrence of these two conditions, although the precise biological mechanisms linking them remain inadequately understood. This review synthesizes the existing body of literature on sarcopenia and late-life depression, examining their definitions, prevalence, clinical presentations, and available treatments. The goal is to clarify the potential connections between these comorbidities and offer a theoretical framework for the development of future preventive and therapeutic strategies.

Association between food intake frequency and psychological distress following the Great East Japan Earthquake: the Fukushima Health Management Survey FY 2012

BACKGROUND

Changes in diet following the Great East Japan Earthquake may affect the mental health of evacuees. However, a large-scale data analysis on this topic is still lacking. Therefore, this study aimed to investigate the relationship between the frequency of food intake per week and psychological distress and traumatic reactions among Fukushima residents two years after the disaster.

METHODS

Multivariable-adjusted logistic regression analysis was performed to predict the relationship between food intake frequency and psychological distress or traumatic reactions between individuals with and without evacuation experience. The study used data from the fiscal year (FY) 2012 Survey on Mental Health and Lifestyle two years after the Great East Japan Earthquake. A total of 42,160 participants aged 30-89 years were included in this study. Those who lived in the evacuation area after the earthquake and were residing in temporary housing or evacuation centers were categorized as having evacuation experience.

RESULTS

Non-evacuees and evacuees who consumed rice more frequently (≥ 5 times/week) had lower rates of psychological distress and traumatic symptoms. Furthermore, both non- evacuees and evacuees who frequently consumed light-colored vegetables and fruits exhibited less psychological distress, whereas those who frequently consumed vegetable juice (for only non-evacuees) and fruit juice (for both non-evacuees and evacuees) exhibited more psychological distress and traumatic symptoms.

CONCLUSION

These findings indicate a potential relationship between dietary choices and mental health among residents in the evacuation area two years after an earthquake. It will be necessary to elucidate this relationship in more detail through longitudinal research in the future.

Lipid profiles in major depression, both with and without metabolic syndrome: associations with suicidal behaviors and neuroticism

BACKGROUND

Significant associations exist between major depressive disorder (MDD), metabolic syndrome (MetS), and cardiovascular disease, potentially attributable to heightened atherogenicity. This study aimed to ascertain if MDD, depression severity, suicidal behaviors, and neuroticism associate with elevated pro-atherogenic indices and reduced anti-atherogenic indices, including a reverse cholesterol transport (RCT) index.

METHODS

This study comprised 34 healthy controls and 33 MDD patients without MetS, and 35 controls and 31 MDD patients with MetS. It assessed total cholesterol (TC) and free cholesterol (FC), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides (TG), apolipoprotein (ApoA), ApoB, cholesterol esterification rate, and a RCT composite.

RESULTS

No significant associations between MDD and lipids were seen in the total study group that combined individuals with and without MetS. In individuals devoid of MetS, MDD is significantly correlated with (a) elevated FC, TG, ApoB, Castelli risk index 1, and ApoB/ApoA, and (b) diminished HDLc, ApoA, and RCT index. In individuals without MetS, there are notable correlations between the severity of depression, suicidal tendencies, neuroticism, and ApoB/ApoA, Castelli risk, and RCT indices.

CONCLUSIONS

The link between lipids and MDD features cannot be adequately estimated by combining participants with and without MetS. It should be examined in a study sample that excludes subjects with MetS. The depression phenome, suicidal behaviors, and neuroticism correlate with diminished RCT and heightened atherogenicity, which are likely implicated in the pathophysiology of MDD. Increased atherogenicity and lowered RCT may represent novel drug targets for the treatment and prevention of MDD, neuroticism, and suicidal behaviors.

Depression as a risk factor for Alzheimer's disease: A human post-mortem study

Depression is associated with persistent low mood. In mid to late life, it has been identified as a risk factor for Alzheimer's disease (AD) with evidence that depression might be an early manifestation of AD. Although the underlying mechanisms by which depression enhances AD development remain unknown, there are several features commonly seen in both diseases such as the presence of neuroinflammation. In this study, we aimed to identify whether neuroinflammation is increased in depression as observed in the early stages of AD by examining post-mortem human brain tissue. Post-mortem human brain tissue from 54 cases with depression and 37 controls without depression were retrieved from the Douglas Bell Canada Brain Bank. Sixteen early-stage AD cases defined as a Braak stage III-IV and 15 controls were sourced from the South West Dementia Brain Bank. Frozen tissue from the dorsal prefrontal cortex was obtained for all cases in order to measure inflammatory proteins (IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and TNF-α) and endothelial markers (ICAM-1, VCAM) using ELISA and MesoScale Multiplex Assays. In the depression group, increase of IL-6 and IL-10, and decrease of IL-1β were observed compared to controls, with no changes detected for the other cytokines and the endothelial markers. In early-stage AD cases, only increased ICAM-1 expression was found compared to controls, indicating endothelial activation as an early feature of AD. None of the cytokines measured showed alteration of their expression in early-stage AD cases. Depression, but not AD, was associated with evidence of neuroinflammation. Depression may increase AD risk through different mechanism(s) than inflammation.

The Role of Mitochondrial Dysfunction-Mediated Changes in Immune Cytokine Expression in the Pathophysiology and Treatment of Major Depressive Disorder

Recent studies have demonstrated an association between major depressive disorder (MDD) and both mitochondrial dysfunction and alterations in pro-inflammatory cytokine expression, suggesting that such changes may be key drivers of MDD pathogenesis. Mechanistically, changes in mitochondrial function are related to endoplasmic reticulum stress, reactive oxygen species production, oxidative phosphorylation, apoptosis, and disrupted calcium ion homeostasis, all of which trigger the activation of signaling cascades that affect the expression of pro-inflammatory cytokines, including tumor necrosis factor alpha, interleukin 1, interleukin 6, and interferons. Certain factors present in the gut microbiota ecosystem can influence communication between microorganisms and the brain through the neuroendocrine, immune, and autonomic nervous systems, thereby altering mitochondrial function and cytokine production. This review article explores the means through which mitochondria regulate immune cytokine expression and the role of mitochondrial dysfunction in the pathogenesis and treatment of MDD to provide new perspectives for the diagnosis of this disease and the development of novel therapeutic interventions with greater efficacy and improved safety profiles.

The role of microbiome in gut-brain-axis dysbiosis causing depression: From mechanisms to treatment

Gut microbiota not only affects the function of the gastrointestinal tract but also the function of other organs, including the brain. The microbiota-gut-brain axis reflects the constant bidirectional communication between the central nervous system and the gastrointestinal tract. Gut microbiota metabolites can cross brain barriers, the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSF) and influence neuropsychiatric disorders, including depression. In recent years, the communication between the microbiome and brain in depression has been extensively studied in humans and animal models. In this chapter, we summarise the current literature on the role of gut microbiota in depression, focusing in particular on brain barriers and bidirectional gut-brain communication.

Association of Oral Microbiome Diversity With Depression Status: NHANES 2009-2012

OBJECTIVES

To investigate the relationship between oral microbial diversity and depression symptoms in the U.S.

POPULATION

METHODS

We utilized the US National Health and Nutrition Examination Survey (NHANES; 2009-2012) to assess the association between oral microbial diversity and depression symptoms. A cut-off PHQ-9 score of 15 was used to define severe depression symptoms. We conducted the multivariate linear regression to explore the association of the amplicon sequence variants (ASVs) with PHQ-9 scores. A restricted cubic spline (RCS) model was introduced to curve the dose-response relationship. A logistic regression model was used to calculate the odds ratio (OR) and 95% confidence interval (CI) of the association between ASVs and the risk of severe depression symptoms. Based on Bray-Curtis dissimilarity of beta diversity, analysis of similarity (ANOSIM) is used to assess the dissimilarity between different depression groups.

RESULTS

A total of 1497 participants were included, with 111 (7.41%) meeting the criteria for severe depression. After adjusting for confounders, we found that ASVs were negatively correlated with PHQ-9 scores (β = -0.008, p = 0.014). The RCS plot showed a linear relationship (pnon-linear = 0.232). Logistic regression showed that ASVs were associated with a decreased risk of severe depression symptoms (OR = 0.992, p = 0.003). Analysis of β diversity identified a statistically significant difference (R = 0.087, p = 0.003). Additionally, we developed a nomogram to estimate an individual's risk of severe depression symptoms.

CONCLUSIONS

Alpha diversity of the oral microbiota was associated with a reduced risk of severe depression symptoms, which could contribute to the early identification and intervention of severe depression.

Association of systemic immune inflammation index with depression among adult type 2 diabetic patients in a tertiary hospital, Ethiopia, 2022

Background

The inflammatory and hormonal aspects of T2DM can influence the development or worsening of depressive symptoms. While most of the burden had due consideration, the mental health impact of T2DM such as depression is often unnoticed, undiagnosed, or untreated. Despite some studies exploring depression in Ethiopian T2DM patients, none have investigated the predictive role of the Systemic Immune inflammation Index (SII) in depression.

Objective

This study aimed to determine the prevalence of depression and its association with the Systemic Immune Inflammation Index (SII), socio-economic factors, and behavioral predictors among adult T2DM patients at Jigjiga University Comprehensive Specialized (JJU CS) Hospital.

Methods and materials

A hospital-based cross-sectional study was conducted from Oct 3 to Nov 13/2022 at JJUSH. Depression was assessed by using the Patient Health Questionnaire (PHQ-9). A complete blood count was done to calculate SII. Data entry was conducted using Epidata version 4.6 and subsequently analyzed in SPSS-V-26. Multiple logistic regression with the backward elimination method was performed. Variables with a p-value < 0.05 were considered statistically significant at a 95% CI.

Results

A total of 263 T2DM patients were recruited in the study. Of these, 134 individuals (51%) were male. The overall prevalence of depression was 47.1%. Of the 263 enrolled T2DM patients, the majority, 142 (54%) had elevated SII. A multivariable logistic regression analysis indicated that high SII (AOR= 2.76), current Khat chewers (AOR= 2.83), ex-Khat chewers (AOR= 4.12), and female sex (AOR= 2.68) were identified independent predictors of depression.

Discussion

There was a high prevalence of depression among T2DM patients on follow-up at JJUSH. As well, SII, Khat chewing, and female sex were identified as predictors of depression. Therefore, relevant stakeholders should work towards control of systemic inflammation, avoidance of risky behaviors such as khat chewing, and promotion of healthy behavior particularly among females.

Is Nasal Dysbiosis a Required Component for Neuroinflammation in Major Depressive Disorder?

Human microbiota is known to influence immune and cerebral responses by direct and/or indirect mechanisms, including hypothalamic-pituitary-adrenal axis signaling, activation of neural afferent circuits to the brain, and by altering the peripheral immune responses (cellular and humoral immune function, circulatory inflammatory cells, and the production of several inflammatory mediators, such as cytokines, chemokines, and reactive oxygen species). The inflammatory responses in the nasal mucosa (rhinitis) or paranasal sinuses (chronic rhinosinusitis) are dual conditions related with a greater risk for developing depression. In the nasal cavity, anatomic components of the olfactive function are in direct contact with the CNS through the olfactory receptors, neurons, and axons that end in the olfactory bulb and the entorhinal cortex. Local microbiome alterations (dysbiosis) are linked to transepithelial translocation of microorganisms and their metabolites, which disrupts the epithelial barrier and favors vascular permeability, increasing the levels of several inflammatory molecules (both cytokines and non-cytokine mediators: extracellular vesicles (exosomes) and neuropeptides), triggering local inflammation (rhinitis) and the spread of these components into the central nervous system (neuroinflammation). In this review, we discuss the role of microbiota-related immunity in conditions affecting the nasal mucosa (chronic rhinosinusitis and allergic rhinitis) and their relevance in major depressive disorders, focusing on the few mechanisms known to be involved and providing some hypothetical proposals on the pathophysiology of depression.

Psychometric Properties of the Persian Version of Sickness Impact Profile-30 (SIP-30) in Community-Dwelling Older Adults

Purpose: Accurate measurement tools are essential for evaluating the health-related quality of life in older adults. We aimed to translate and evaluate the psychometric properties of the Sickness Impact Profile-30 (SIP-30) in community-dwelling older adults. Materials and Methods: One hundred and fifty older adults participated in this study. To evaluate construct validity, its correlation with General Health Questionnaire-28, Geriatric Depression Scale-15, Hospital Anxiety and Depression Scale, Modified Health Assessment Questionnaire, Numeric Pain Rating Scale, and Fullerton Advanced Balance Scale was assessed. Reliability features were also investigated. Results: The results of construct validity analysis demonstrated a moderate to high (r = 0.61-0.84) correlation between the total score of SIP-30 and GHQ-28, GDS-15, HADS, MHAQ, and NPRS. There was a moderate inverse (r = -0.67) correlation between the total score of the SIP-30 and the FAB Scale. Test-retest reliability (ICC > 0.83) and internal consistency (α = 0.94) of the Persian SIP-30 were high. Conclusions: The results indicated that the Persian SIP-30 is a reliable and valid measure to assess health-related quality of life in community-dwelling older adults.

Association between serum neurofilament light chains and depression: A cross-sectional study based on NHANES 2013-2014 database

BACKGROUND

Serum neurofilament light chain (sNfl), identified as a promising biomarker, is a protein released into the bloodstream post-axonal damage. Studies on its correlation with depression, however, remains scarce. The purpose of this study was to investigate the potential relationship between sNfL levels and risk of depression among a representative segment of the U. S. populace.

METHODS

This study included 1,909 participants from the 2013-2014 National Health and Nutrition Examination Survey. The 9-item Patient Health Questionnaire (PHQ-9 scale) assessed depression symptoms, while sNfl concentrations were measured using the Attelica fully automated immunoassay system. The logistic regression, restricted cubic splines (RCS), and subgroup analysis were performed to assess the relationship between sNfL, lnsNfL (log-transformed values of sNfl), and depression.

RESULTS

After adjusting for sociodemographic variables, lifestyle, and chronic conditions, sNfl and lnsNfL levels positively correlated with depression. A unit increase in sNfL and lnsNfL levels was linked to a 0.7 % and 33.8 % rise in depression risk, respectively [OR (95 % CI): 1.007 (1.000, 1.014), p = 0.041 for sNfl; 1.338 (1.015, 1.764), p = 0.039 for lnsNfl]. Additionally, a positive linear association was observed between lnsNfl levels and the risk of depression (p for overall = 0.039, p for nonlinear = 0.189 in RCS). No significant differences were observed across subgroups between lnsNfl and depression, with no significant impact on this relationship from subgroups (All p for interaction >0.05).

CONCLUSION

The findings of our study suggest a significant positive correlation between sNfl and depression, warranting further investigation into the molecular dynamics linking sNfL to depression and subgroup variability.

Cerium oxide-modified Pd nanosheets encapsulated by red blood cell membranes for high-efficiency RONS scavenging in depression treatment

Depression, a common and high-morbidity mental illness, can cause severe physical and psychiatric disorder. Recently, elevated levels of reactive oxygen and nitrogen species (RONS) have been recognized as a potential pathogenesis of depression. Unfortunately, available therapies provide limited outcomes in treating RONS-related depression symptoms. In addition, the low blood-brain barrier (BBB) penetration efficiency of some drugs is another major barrier to depression treatment. This study developed cerium oxide-modified Pd (Pd-CeO2) nanosheets with outstanding antioxidant activities for depression therapy. Under physiological conditions, Pd-CeO2 exhibited significant O2˙- and H2O2 clearance through their superoxide dismutase (SOD) and catalase (CAT) activities. Meanwhile, Pd-CeO2 also displayed the ability to scavenge ˙OH and reactive nitrogen radicals (RNS). What's more, when incorporated with biocompatible red blood cell (RBC) membranes, Pd-CeO2@RBC could overcome the BBB and protect brain tissues from oxidative damage caused by RONS. As a result, Pd-CeO2@RBC therapy reduced the proliferation of microglia and astrocytes and alleviated neuroinflammation and depression-like behaviors. This research not only provides a novel strategy for the effective treatment of depression, but also paves the way for new therapeutic options of nanozymes in neurological disorders.

SEP-363856 attenuates CUMS-induced depression-like behaviours and reverses hippocampal neuronal injuries

OBJECTIVES

This study employed a chronic unpredictable mild stress (CUMS) model to examine the antidepressant properties of SEP-363856.

METHODS

The sucrose preference test (SPT) was employed to evaluate anhedonia, the open field test (OFT) to measure locomotor activity and exploratory behaviour, the elevated plus-maze (EPM) to assess anxiety-like behaviour, and the tail suspension test (TST) and forced swimming test (FST) to determine despair behaviour. qRT-PCR was implemented to evaluate gene expression levels in the hippocampus. Western blot, and ELISA were implemented to evaluate hippocampal protein expression, and Nissl staining was implemented to identify hippocampal neuronal injury.

RESULTS

The 10 mg/kg dosage of SEP-363856 and fluoxetine significantly improved depressive-like behaviours as assessed by the SPT, OFT, EPM, TST, and FST. This was associated with improved hippocampal neuronal damage, enhanced mRNA expression of brain-derived neurotrophic factor, synaptophysin, and postsynaptic density 95. SEP-363856 increased the levels of insulin-like growth factor-1 (IGF-1), IGF-1 receptor β, phospho-phosphatidylinositide 3-kinase, and phospho-protein kinase B in the brain.

CONCLUSIONS

The antidepressant-like effects of SEP-363856 are linked to increased hippocampal neurotrophic factors, decreased hippocampus neuronal lesions, and activation of the IGF-1Rβ/PI3K/AKT signalling pathway. The latter may serve as a novel drug target for the treatment of depression.

The neurodegenerative hypothesis of depression and the influence of antidepressant medications

Depression is a complex neurological disease that holds many theories on its aetiology and pathophysiology. The monoamine strategy of treating depression with medications to increase levels of monoamines in the (extra)synapse, primarily through the inhibition of monoamine transporters, does not always work, as seen in patients that lack a response to multiple anti-depressant exposures, as well as a lack of depressive symptoms in healthy volunteers exposed to monoamine reduction. Depression is increasingly being understood not as a single condition, but as a complex interplay of adaptations in various systems, including inflammatory responses and neurotransmission pathways in the brain. This understanding has led to the development of the neurodegenerative hypothesis of depression. This hypothesis, which is gaining widespread acceptance posits that both oxidative stress and inflammation play significant roles in the pathophysiology of depression. This article is a review of the literature focused on neuroinflammation in depression, as well as summarised studies of anti-inflammatory and antioxidant effects of antidepressants.

Brain-based correlates of depression and traumatic brain injury: a systematic review of structural and functional magnetic resonance imaging studies

Introduction

Depression is prevalent after traumatic brain injury (TBI). However, there is a lack of understanding of the brain-based correlates of depression post-TBI. This systematic review aimed to synthesize findings of structural and functional magnetic resonance imaging (MRI) studies to identify consistently reported neural correlates of depression post-TBI.

Methods

A search for relevant published studies was conducted through OVID (MEDLINE, APA PsycINFO, and Embase), with an end date of August 3rd, 2023. Fourteen published studies were included in this review.

Results

TBI patients with depression exhibited distinct changes in diffusion- based white matter fractional anisotropy, with the direction of change depending on the acuteness or chronicity of TBI. Decreased functional connectivity (FC) of the salience and default mode networks was prominent alongside the decreased volume of gray matter within the insular, dorsomedial prefrontal, and ventromedial prefrontal cortices. Seven studies reported the correlation between observed neuroimaging and depression outcomes. Of these studies, 42% indicated that FC of the bilateral medial temporal lobe subregions was correlated with depression outcomes in TBI.

Discussion

This systematic review summarizes existing neuroimaging evidence and reports brain regions that can be leveraged as potential treatment targets in future studies examining depression post-TBI.

Intranasal AdipoRon Mitigated Anxiety and Depression-Like Behaviors in 6-OHDA-Induced Parkinson 's Disease Rat Model: Going Beyond Motor Symptoms

Depression and anxiety are prevalent neuropsychiatric conditions among patients with Parkinson's disease (PD), which may manifest prior to motor symptoms. As levodopa, a prominent treatment for PD motor symptoms, provides few benefits for mood-related abnormalities, tackling non-motor symptoms is particularly important. AdipoRon (Ad), an adiponectin agonist, has demonstrated neuroprotective effects by suppressing neuroinflammatory responses and activating the AMPK/Sirt-1 signaling pathway. This study looked at the potential advantages and underlying mechanisms of intranasal Ad in a rat model of PD induced by 6-hydroxydopamine (6-OHDA). We found that Ad at doses of 1 and 10 µg for 21 days exhibited anxiolytic- and antidepressant effects in the open field (OF) test, elevated plus maze (EPM), sucrose splash test, and forced swimming test in a PD model caused by a unilateral 6-OHDA injection into the medial forebrain bundle (MFB). The Ad also lowered the levels of corticosterone in the blood, decreased inflammasome components (NLRP3, caspase 1, and IL-1β), and increased Sirt-1 protein levels in the prefrontal cortex (PFC) of PD rats. We conclude that Ad ameliorates anxious and depressive-like behaviors in the PD rat model through stimulating the AMPK/Sirt-1 signaling and blocking the NLRP3 inflammasome pathways in the PFC.

Fumaric acid protects rats from ciprofloxacin-provoked depression through modulating TLR4, Nrf-2, and p190-rho GTP

Depression is a persistent illness affecting health, behavior, and performance in life. Worldwide morbidity and mortality are caused by depression. The current study intended to explore fumaric acid's potential protective effect against ciprofloxacin-provoked depression in rats and to determine its mechanism of action by studying its antioxidant and anti-inflammatory properties. Five groups of male Wistar albino rats (120 g ± 20) were employed; the first group received physiological saline, the second group received fumaric acid (80 mg/kg/day; orally) for 3 weeks, the third group was administered ciprofloxacin (50 mg/kg/day; orally) for 3 weeks to induce depression, the fourth group received a daily low dose of fumaric acid (40 mg/kg; orally) concurrent with ciprofloxacin and the fifth group received a daily high dose of fumaric acid (80 mg/kg; orally) concurrent with ciprofloxacin for 21 days. Then, behavior tests, oxidative stress indicators, inflammatory biomarkers, neurotransmitters, p190 Rho GTP, and histopathological examination were evaluated. Ciprofloxacin significantly increased oxidative stress biomarkers [malondialdehyde (MDA) as a lipid peroxidation marker and nitric oxide (NO)] and biomarkers of inflammation [Toll-like receptor4 (TLR-4)] and tumor necrosis factor-alpha (TNF-α) with reduction in the activities of the nuclear factor erythroid 2-related factor 2 (Nrf-2) and catalase as well as brain contents of neurotransmitters and P190-RHO GTP. In addition, it causes necrosis of neurons and mild loss of Purkinje cells. Fumaric acid eliminates these effects of ciprofloxacin. Fumaric acid has beneficial effects as an anti-depressant in Wistar albino male rats that received ciprofloxacin.

Investigating the causal relationship between major depressive disorder and benign prostatic hyperplasia: a bidirectional Mendelian randomisation study

BACKGROUND

Evidence from various cohort studies indicate a potential association between depressive disorder and benign prostatic hyperplasia (BPH), yet findings are inconsistent. This study employs bidirectional two-sample Mendelian randomisation (MR) analysis to explore the causal relationship between BPH and major depressive disorder (MDD).

METHODS

Genetic variants strongly associated with MDD were extracted as instrumental variables conducted by the Psychiatric Genomics Consortium (PGC). Two sets of genetic variants associated with BPH were extracted from the recent FinnGen and Medical Research Council-Integrative Epidemiology Unit Consortium of BPH as the discovery and replication stages, respectively. Bidirectional MR analysis employed methods such as inverse variance weighted, MR-Egger, weighted median, maximum likelihood, and weighted mode. The inverse variance weighted method was primarily used to evaluate the causal relationship.

RESULTS

MR analysis in both the discovery and replication stages showed a significant causal relationship between MDD and the risk of BPH (discovery stages, odds ratio (OR) = 1.1146, 95% CI 1.0058-1.2353, P = 0.03852; replication stage, OR: 1.0042, 95% CI 1.0019-1.0065, P = 0.0004). No causal relationship was found between BPH and MDD risk in the reverse MR analysis.

CONCLUSIONS

Our findings highlight a significant association between MDD and an increased risk of BPH development. Further investigation is needed to elucidate the underlying mechanisms linking depression and BPH.

T cell activation and lowered T regulatory cell numbers are key processes in severe major depressive disorder: Effects of recurrence of illness and adverse childhood experiences

BACKGROUND

Major depressive disorder (MDD) is characterized by increased T helper (Th)1 polarization, T cell activation (e.g., CD71+ and CD40L+), and cannabinoid receptor type 2 bearing CD20+ B cells; and lower T regulatory (Treg) numbers.

AIMS

To delineate the effects of adverse childhood experiences (ACEs) and recurrence of illness (ROI) on activated T and CB2-bearing B populations, and Tregs, including FoxP3 + CD152+, FoxP3 + GARP+, and FoxP3 + CB1+ cells.

METHODS

We measured ROI, ACEs, the number of activated T cells, Tregs, and CD20 + CB2+ B cells, in 30 MDD patients and 20 healthy controls.

RESULTS

A larger part of the variance in the depression phenome (40.8 %) was explained by increased CD20 + CB2+ and activated T cells, and lowered Tregs. ROI and lifetime suicidal behaviors were significantly and positively associated with CD20 + CB2+, CD3 + CD71+, CD3 + CD40L+, CD4 + CD71+, CD4 + CD40L+, and CD4HLADR+ numbers. ROI was significantly correlated with CD8 + CD40L+ numbers. The sum of ACEs was significantly associated with CD20 + CB2+, CD3 + CD40L+, CD4 + 40 L+ numbers, T cell activation (positively) and Treg (inversely) indices. One replicable latent vector could be extracted from activated T cells, lifetime and current suicidal behaviors, number of depressive episodes, and severity of depression, and 48.8 % of its variance was explained by ACEs.

CONCLUSIONS

ACE-induced activation of T effector and cytotoxic cells and B cells with autoimmune potential, coupled with lowered Treg numbers are a key component of depression. The findings indicate that increasing ROI, the phenome of depression and suicidal behaviors, are caused by autoimmune processes, which are the consequence of ACEs and increasing sensitization of immune responses.

Association of Biomarkers with the Severity of Depression

Background

The pathogenesis of depression remains elusive and uncertain. The literature suggests that low-grade systemic inflammation might contribute to the etiology of depression. Other markers that are studied are serum magnesium and serum cortisol. The association between these factors might help understand the etiology.

Methods

This was a cross-sectional study conducted on a sample of 40 participants. Socio-demographic data was noted, and the Hamilton depression rating scale was applied to rate the severity of depression. Blood samples were drawn at 8 a.m. to record a complete blood picture (to derive the neutrophil-lymphocyte ratio (NLR)), C-reactive protein, serum magnesium, and serum cortisol.

Results

In this study, conducted on a sample size of 40, inflammatory markers such as C-reactive protein (CRP: mg/dl) and NLR were significantly increased to 15.52 ± 13.10 and 6.46 ± 2.92, respectively, showing an underlying inflammatory pathology. Serum cortisol (µg/dl) was also raised to 22.30 ± 5.46, and there was a fall in serum magnesium. Also, it is noteworthy that all these markers were significantly associated with the severity of depression, as the Pearson correlation between the Hamilton depression rating scale-21 item (HAM-D-21) score and CRP, NLR, and serum cortisol was positive and statistically significant (r = 0.55, p < .01; r = 0.51, p = .01; r = 0.46, p = .002). The Pearson correlation between the HAM-D score and serum magnesium was negative and statistically significant (r = -0.82, p < .01).

Conclusion

There is a state of systemic inflammation, hypercortisolemia, and hypomagnesemia in depressive disorders.

Metabolic Perturbations Associated with both PFAS Exposure and Perinatal/Antenatal Depression in Pregnant Individuals: A Meet-in-the-Middle Scoping Review

PURPOSE OF REVIEW

Depression during the perinatal or antenatal period affects at least 1 in 10 women worldwide, with long term health implications for the mother and child. Concurrently, there is increasing evidence associating maternal exposure to per- and poly-fluoroalkyl substances (PFAS) to adverse pregnancy outcomes. We reviewed the body of evidence examining both the associations between PFAS exposure and perturbations in the maternal metabolome, and the associations between the maternal metabolome and perinatal/antenatal depression. Through this, we sought to explore existing evidence of the perinatal metabolome as a potential mediation pathway linking PFAS exposure and perinatal/antenatal depression.

RECENT FINDINGS

There are few studies examining the metabolomics of PFAS exposure-specifically in pregnant women-and the metabolomics of perinatal/antenatal depression, let alone studies examining both simultaneously. Of the studies reviewed (N = 11), the majority were cross sectional, based outside of the US, and conducted on largely homogenous populations. Our review identified 23 metabolic pathways in the perinatal metabolome common to both PFAS exposure and perinatal/antenatal depression. Future studies may consider findings from our review to conduct literature-derived hypothesis testing focusing on fatty acid metabolism, alanine metabolism, glutamate metabolism, and tyrosine metabolism when exploring the biochemical mechanisms conferring the risk of perinatal/antenatal depression due to PFAS exposure. We recommend that researchers also utilize heterogenous populations, longitudinal study designs, and mediation approaches to elucidate key pathways linking PFAS exposures to perinatal/antenatal depression.

The recurrence of illness (ROI) index is a key factor in major depression that indicates increasing immune-linked neurotoxicity and vulnerability to suicidal behaviors

In this study, we aimed to investigate the associations between the recurrence of illness (ROI) and biomarkers related to an activated immune network, immune-linked neurotoxicity (INT), and a combined INT and atherogenicity index (METAMMUNE). The study involved 67 healthy controls and 66 outpatient MDD (OMDD) participants. We utilized a Multiplex method to measure 48 cytokines and examined INT and METAMMUNE composite scores in association with different ROI indices. Our findings revealed that a ROI index was successfully created by extracting a validated principal component, from the physician-rated or self-declared number of depressive episodes, the frequency of lifetime suicidal ideation and attempts. ROI was significantly associated with INT and METAMMUNE indices, neuroticism, lifetime and current suicidal behaviors, and the phenome. Our analysis also revealed that a significant portion of the variance in the OMDD phenome, which includes current suicidal behaviors, anxiety, and depression, can be accounted for by the regression on INT, ROI, and emotional neglect and abuse. A validated latent construct was successfully extracted from the three ROI components, INT and METAMMUNE indices. The results indicate that increasing ROI indicates heightened immune-metabolic abnormalities, increased risk of suicidal behaviors, and elevated severity of lifetime and current phenome features.

"Inflamed" depression: A review of the interactions between depression and inflammation and current anti-inflammatory strategies for depression

Depression is a common mental disorder, the effective treatment of which remains a challenging issue worldwide. The clinical pathogenesis of depression has been deeply explored, leading to the formulation of various pathogenic hypotheses. Among these, the monoamine neurotransmitter hypothesis holds a prominent position, yet it has significant limitations as more than one-third of patients do not respond to conventional treatments targeting monoamine transmission disturbances. Over the past few decades, a growing body of research has highlighted the link between inflammation and depression as a potential key factor in the pathophysiology of depression. In this review, we first summarize the relationship between inflammation and depression, with a focus on the pathophysiological changes mediated by inflammation in depression. The mechanisms linking inflammation to depression as well as multiple anti-inflammatory strategies are also discussed, and their efficacy and safety are assessed. This review broadens the perspective on specific aspects of using anti-inflammatory strategies for treating depression, laying the groundwork for advancing precision medicine for individuals suffering from "inflamed" depression.

Increased malondialdehyde and nitric oxide formation, lowered total radical trapping capacity coupled with psychological stressors are strongly associated with the phenome of first-episode mild depression in undergraduate students

Undergraduate students are frequently afflicted by major depressive disorder (MDD). Oxidative and nitrosative stress (O&NS) has been implicated in the pathophysiology of MDD. There is no information regarding whether mild outpatient MDD (SDMD) and first episode SDMD (FE-SDMD) are accompanied by O&NS. The current study compared lipid hydroperoxides (LOOH), malondialdehyde (MDA), advanced protein oxidation products, nitric oxide metabolites (NOx), thiol groups, plasma total antioxidant potential (TRAP), and paraoxonase 1 activities among SDMD and FE-SDMD patients versus healthy controls. We found that SDMD and FE-SDMD exhibit elevated MDA and NOx, and decreased TRAP and LOOH as compared with controls. There was a significant and positive correlation between O&NS biomarkers and adverse childhood experiences (ACEs), and negative life events (NLEs). O&NS pathways, NLEs and ACEs accounted for 51.7 % of the variance in the phenome of depression, and O&NS and NLS explained 42.9 % of the variance in brooding. Overall, these results indicate that SDMD and FE-SDMD are characterized by reduced total antioxidant defenses and increased aldehyde and NOx production. The combined effects of oxidative and psychological stressors are substantially associated with the manifestation of SDMD.

An integrated machine learning framework for developing and validating a diagnostic model of major depressive disorder based on interstitial cystitis-related genes

BACKGROUND

Major depressive disorder (MDD) and interstitial cystitis (IC) are two highly debilitating conditions that often coexist with reciprocal effect, significantly exacerbating patients' suffering. However, the molecular underpinnings linking these disorders remain poorly understood.

METHODS

Transcriptomic data from GEO datasets including those of MDD and IC patients was systematically analyzed to develop and validate our model. Following removal of batch effect, differentially expressed genes (DEGs) between respective disease and control groups were identified. Shared DEGs of the conditions then underwent functional enrichment analyses. Additionally, immune infiltration analysis was quantified through ssGSEA. A diagnostic model for MDD was constructed by exploring 113 combinations of 12 machine learning algorithms with 10-fold cross-validation on the training sets following by external validation on test sets. Finally, the "Enrichr" platform was utilized to identify potential drugs for MDD.

RESULTS

Totally, 21 key genes closely associated with both MDD and IC were identified, predominantly involved in immune processes based on enrichment analyses. Immune infiltration analysis revealed distinct profiles of immune cell infiltration in MDD and IC compared to healthy controls. From these genes, a robust 11-gene (ABCD2, ATP8B4, TNNT1, AKR1C3, SLC26A8, S100A12, PTX3, FAM3B, ITGA2B, OLFM4, BCL7A) diagnostic signature was constructed, which exhibited superior performance over existing MDD diagnostic models both in training and testing cohorts. Additionally, epigallocatechin gallate and 10 other drugs emerged as potential targets for MDD.

CONCLUSION

Our work developed a diagnostic model for MDD employing a combination of bioinformatic techniques and machine learning methods, focusing on shared genes between MDD and IC.

The association between depressive symptoms and high-sensitivity C-reactive protein: Is body mass index a moderator?

Objective

Depression and obesity are highly comorbid conditions with shared biological mechanisms. It remains unclear how depressive symptoms and body mass index (BMI) interact in relation to inflammation. This cross-sectional study investigated the independent associations of depressive symptoms and BMI with high sensitivity C-reactive protein (hs-CRP), as well as the moderating role of BMI on the depressive symptoms-hs-CRP association.

Methods

Participants (n = 8827) from the 2015-2018 National Health and Nutrition Examination Surveys were aged ≥20 with a BMI ≥18.5 kg/m2, completed the Depression Screener, and had hs-CRP data. Multivariable linear regression was used to analyze hs-CRP in relation to depressive symptoms and BMI. An interaction term was included to examine whether the depressive symptoms-hs-CRP relationship differs depending on BMI.

Results

There was a slight, albeit non-significant, increase in hs-CRP levels with each one-point increase in depressive symptoms (aCoef.Estm. = 0.01, 95% CI = -0.05, 0.06, p = 0.754). Participants with overweight (aCoef.Estm. = 1.07, 95% CI = 0.61, 1.53, p < 0.001) or obese (aCoef.Estm. = 3.51, 95% CI = 3.04, 3.98, p < 0.001) BMIs had higher mean hs-CRP levels than those with a healthy BMI. There were no significant interactions between depressive symptoms and overweight (aCoef.Estm. = 0.04, 95% CI = -0.04, 0.13, p = 0.278) or obese (aCoef.Estm. = 0.11, 95% CI = -0.01, 0.22, p = 0.066) BMI indicating a lack of difference in the depressive symptoms-hs-CRP association across participants in the healthy versus overweight and obese ranges.

Conclusions

This study suggests that BMI might not act as a moderator in the association between depressive symptoms and hs-CRP. Results should be replicated in larger samples. Further research is warranted to understand underlying mechanisms.

Mapping pathways to neuronal atrophy in healthy, mid-aged adults: From chronic stress to systemic inflammation to neurodegeneration?

Growing evidence implicates systemic inflammation in the loss of structural brain integrity in natural ageing and disorder development. Chronic stress and glucocorticoid exposure can potentiate inflammatory processes and may also be linked to neuronal atrophy, particularly in the hippocampus and the human neocortex. To improve understanding of emerging maladaptive interactions between stress and inflammation, this study examined evidence for glucocorticoid- and inflammation-mediated neurodegeneration in healthy mid-aged adults. N = 169 healthy adults (mean age = 39.4, 64.5% female) were sampled from the general population in the context of the ReSource Project. Stress, inflammation and neuronal atrophy were quantified using physiological indices of chronic stress (hair cortisol (HCC) and cortisone (HEC) concentration), systemic inflammation (interleukin-6 (IL-6), high-sensitive C-reactive protein (hs-CRP)), the systemic inflammation index (SII), hippocampal volume (HCV) and cortical thickness (CT) in regions of interest. Structural equation models were used to examine evidence for pathways from stress and inflammation to neuronal atrophy. Model fit indices indicated good representation of stress, inflammation, and neurological data through the constructed models (CT model: robust RMSEA = 0.041, robust χ2 = 910.90; HCV model: robust RMSEA <0.001, robust χ2 = 40.95). Among inflammatory indices, only the SII was positively associated with hair cortisol as one indicator of chronic stress (β = 0.18, p < 0.05). Direct and indirect pathways from chronic stress and systemic inflammation to cortical thickness or hippocampal volume were non-significant. In exploratory analysis, the SII was inversely related to mean cortical thickness. Our results emphasize the importance of considering the multidimensionality of systemic inflammation and chronic stress, with various indicators that may represent different aspects of the systemic reaction. We conclude that inflammation and glucocorticoid-mediated neurodegeneration indicated by IL-6 and hs-CRP and HCC and HEC may only emerge during advanced ageing and disorder processes, still the SII could be a promising candidate for detecting associations between inflammation and neurodegeneration in younger and healthy samples. Future work should examine these pathways in prospective longitudinal designs, for which the present investigation serves as a baseline.

Aspartame-induced cognitive dysfunction: Unveiling role of microglia-mediated neuroinflammation and molecular remediation

Aspartame, an artificial sweetener, is consumed by millions of people globally. There are multiple reports of aspartame and its metabolites affecting cognitive functions in animal models and humans, which include learning problems, headaches, seizures, migraines, irritable moods, anxiety, depression, and insomnia. These cognitive deficits and associated symptoms are partly attributed to dysregulated excitatory and inhibitory neurotransmitter balance due to aspartate released from aspartame, resulting in an excitotoxic effect in neurons, leading to neuronal damage. However, microglia, a central immunocompetent cell type in brain tissue and a significant player in inflammation can contribute to the impact. Microglia rapidly respond to changes in CNS homeostasis. Aspartame consumption might affect the microglia phenotype directly via methanol-induced toxic effects and indirectly via aspartic acid-mediated excitotoxicity, exacerbating symptoms of cognitive decline. Long-term oral consumption of aspartame thus might change microglia's phenotype from ramified to activated, resulting in chronic or sustained activation, releasing excess pro-inflammatory molecules. This pro-inflammatory surge might lead to the degeneration of healthy neurons and other glial cells, impairing cognition. This review will deliberate on possible links and research gaps that need to be explored concerning aspartame consumption, ecotoxicity and microglia-mediated inflammatory cognitive impairment. The study covers a comprehensive analysis of the impact of aspartame consumption on cognitive function, considering both direct and indirect effects, including the involvement of microglia-mediated neuroinflammation. We also propose a novel intervention strategy involving tryptophan supplementation to mitigate cognitive decline symptoms in individuals with prolonged aspartame consumption, providing a potential solution to address the adverse effects of aspartame on cognitive function.

Association between Chronic Pain and Sarcopenia in Greek Community-Dwelling Older Adults: A Cross-Sectional Study

(1) Background: Sarcopenia and chronic pain are prevalent syndromes among older adults that negatively affect their quality of life. The present study aimed to investigate the relationship between chronic pain and sarcopenia among Greek community-dwelling older adults. (2) Methods: Older adults >60 years of age were enrolled in this descriptive, cross-sectional study. Sarcopenia status was assessed according to the EWGSOP2 2019 algorithm. This assessment included the evaluation of muscle strength, body composition and gait speed. Pain location and pain characteristics were assessed using a self-reported questionnaire. Pain severity was assessed via the visual analog scale. The participants were also asked to fill out the SARC-F, the Hospital Anxiety and Depression Scale (HADS) and the Falls Efficacy Scale-International (FES-I) questionnaire. (3) Results: This study included 314 participants with a mean age of 71.3 ± 7.4 years. The prevalence of sarcopenia was 19.4 (n = 61), and 44.26% of the sarcopenic participants recorded chronic pain. Chronic pain was associated with sarcopenia, comorbidities, the number of drugs and HADS. (4) Conclusions: The results demonstrated a high percentage of chronic pain in the sarcopenic population. The results also highlight the importance of the detection of chronic pain in older patients with sarcopenia in order to develop effective preventive and therapeutic strategies.

An Investigation of the Inflammatory Landscape in the Brain and Bone Marrow of the APP/PS1 Mouse

Background

The APP/PS1 mouse model recapitulates pathology of human Alzheimer's disease (AD). While amyloid-β peptide deposition and neurodegeneration are features of AD, the pathology may involve inflammation and impaired vascular regeneration.

Objective

This study evaluated inflammatory environments in the brain and bone marrow (BM), and the impact on brain microvascular density.

Methods

BM and frontal cortex from male nine-month-old APP/PS1 or the control C57Bl6/j mice were studied. Vascular density and inflammatory cells were evaluated in the sections of frontal cortex by immunohistochemistry. Different subsets of hematopoietic stem/progenitor cells (BM) and monocyte-macrophages were characterized by flow cytometry and by clonogenic assays. Myelopoietic or inflammatory factors were evaluated by real-time RT-PCR or by western blotting.

Results

CD34+ or CD31+ vascular structures were lower (p < 0.01, n = 6) in the frontal cortex that was associated with decreased number of Lin-Sca-1+cKit+ vasculogenic progenitor cells in the BM and circulation (p < 0.02, n = 6) compared to the control. Multipotent progenitor cells MPP4, common lymphoid, common myeloid and myeloid progenitor cells were higher in the APP/PS1-BM compared to the control, which agreed with increased numbers of monocytes and pro-inflammatory macrophages. The expression of pro-myelopoietic factors and alarmins was higher in the APP/PS1 BM-HSPCs or in the BM-supernatants compared to the control. Frontal cortices of APP/PS1 mice showed higher number of pro-inflammatory macrophages (CD11b+F4/80+ or CD80+) and microglia (OX42+Iba1+).

Conclusions

These findings show that AD pathology in APP/PS1 mice is associated with upregulated myelopoiesis, which contributes to the brain inflammation and decreased vascularity.

Predicting Depression, Anxiety, and Their Comorbidity among Patients with Breast Cancer in China Using Machine Learning: A Multisite Cross-Sectional Study

Depression and anxiety are highly prevalent among patients with breast cancer. We tested the capacity of personal resources (psychological resilience, social support, and process of recovery) for predicting depression, anxiety, and comorbid depression and anxiety (CDA) among such patients using machine learning (ML). We conducted a cross-sectional survey in Liaoning Province, China, including questions about demographics, COVID-19's impact, and personal resources (707 valid responses). In the training set, we used Lasso logistic regression to establish personal resource models. Subsequently, we used six ML methods and a tenfold cross-validation strategy to establish models combining personal resources, demographics, and COVID-19 impacts. Findings indicate that in total, 21.9%, 35.1%, and 14.7% of participants showed depression, anxiety, and CDA, respectively. Loneliness, vitality, mental health, bodily pain, and self-control predicted depression, anxiety, and CDA. Furthermore, general health predicted depression, and physical function predicted anxiety. Demographic and COVID-19 models were far less predictive than personal resource models (0.505-0.629 vs. 0.826-0.869). Among combined models, the support vector machine model achieved the best prediction (AUC: 0.832-0.873), which was slightly better than the personal resource models. Personal resources features with ML and personal resources can help predict depression, anxiety, and CDA in patients with breast cancer. Accordingly, interventions should target loneliness, bodily pain, vitality, mental health, and self-control.

Inflammatory mediators in major depression and bipolar disorder

Major depressive disorder (MDD) and bipolar disorder (BD) are highly disabling illnesses defined by different psychopathological, neuroimaging, and cognitive profiles. In the last decades, immune dysregulation has received increasing attention as a central factor in the pathophysiology of these disorders. Several aspects of immune dysregulations have been investigated, including, low-grade inflammation cytokines, chemokines, cell populations, gene expression, and markers of both peripheral and central immune activation. Understanding the distinct immune profiles characterizing the two disorders is indeed of crucial importance for differential diagnosis and the implementation of personalized treatment strategies. In this paper, we reviewed the current literature on the dysregulation of the immune response system focusing our attention on studies using inflammatory markers to discriminate between MDD and BD. High heterogeneity characterized the available literature, reflecting the heterogeneity of the disorders. Common alterations in the immune response system include high pro-inflammatory cytokines such as IL-6 and TNF-α. On the contrary, a greater involvement of chemokines and markers associated with innate immunity has been reported in BD together with dynamic changes in T cells with differentiation defects during childhood which normalize in adulthood, whereas classic mediators of immune responses such as IL-4 and IL-10 are present in MDD together with signs of immune-senescence.

Blocking CCR5 activity by maraviroc augmentation in post-stroke depression: a proof-of-concept clinical trial

BACKGROUND

Post-stroke depression (PSD) is a significant impediment to successful rehabilitation and recovery after a stroke. Current therapeutic options are limited, leaving an unmet demand for specific and effective therapeutic options. Our objective was to investigate the safety of Maraviroc, a CCR5 antagonist, as a possible mechanism-based add-on therapeutic option for PSD in an open-label proof-of-concept clinical trial.

METHODS

We conducted a 10-week clinical trial in which ten patients with subcortical and cortical stroke, suffering from PSD. were administered a daily oral dose of 300 mg Maraviroc. Participants were then monitored for an additional eight weeks. The primary outcome measure was serious treatment-emergent adverse events (TEAEs) and TEAEs leading to discontinuation. The secondary outcome measure was a change in the Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

Maraviroc was well tolerated, with no reports of serious adverse events or discontinuations due to intolerance. The MADRS scores substantially reduced from baseline to week 10 (mean change: -16.4 ± 9.3; p < 0.001). By the conclusion of the treatment phase, a favorable response was observed in five patients, with four achieving remission. The time to response was relatively short, approximately three weeks. After the cessation of treatment, MADRS scores increased at week 18 by 6.1 ± 9.6 points (p = 0.014).

CONCLUSIONS

Our proof-of-concept study suggests that a daily dosage of 300 mg of Maraviroc may represent a well-tolerated and potentially effective pharmacological approach to treating PSD. Further comprehensive placebo-controlled studies are needed to assess the impact of Maraviroc augmentation on PSD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05932550, Retrospectively registered: 28/06/2023.

Imbalance of Plasma Copper and Zinc Levels and the Association Between the Cu/Zn Ratio and Lipid Peroxidation in Algerian Bipolar Patients

Trace elements, through their interaction with biomolecules, can play an important role in the pathophysiology of bipolar disorder and protect against oxidative stress effects. The purpose of this study is to examine plasma concentration levels of zinc (Zn) and copper (Cu) of Algerian patients, diagnosed with bipolar disorder, and to compare these levels with those of healthy controls. The Cu/Zn ratio was calculated to explore a possible correlation between these elements and lipid peroxidation in the study groups. A total of 33 patients diagnosed with bipolar disorder and 38 healthy subjects participated in this study. Plasma copper and zinc concentrations were measured using a polarographic analyzer. The marker of plasma lipid peroxidation (Malondialdehyde: MDA) was determined by UV spectrophotometry. Plasma Cu concentrations were higher in patients compared to controls (p < 0.05), while the Zn level was significantly lower. Consequently, the Cu/Zn ratio was significantly different between patients and controls. Regarding MDA, no significant difference was noticed between the two study groups. However, in patients, a negative correlation was found between MDA and Cu/Zn ratio (r= -0.38, p= 0.027). These results suggested that an elevated Cu/Zn ratio is associated with attenuated lipid peroxidation in our bipolar patients.

Psilocybin for dementia prevention? The potential role of psilocybin to alter mechanisms associated with major depression and neurodegenerative diseases

Major depression is an established risk factor for subsequent dementia, and depression in late life may also represent a prodromal state of dementia. Considering current challenges in the clinical development of disease modifying therapies for dementia, the focus of research is shifting towards prevention and modification of risk factors to alter the neurodegenerative disease trajectory. Understanding mechanistic commonalities underlying affective symptoms and cognitive decline may reveal biomarkers to aid early identification of those at risk of progressing to dementia during the preclinical phase of disease, thus allowing for timely intervention. Adult hippocampal neurogenesis (AHN) is a phenomenon that describes the birth of new neurons in the dentate gyrus throughout life and it is associated with spatial learning, memory and mood regulation. Microglia are innate immune system macrophages in the central nervous system that carefully regulate AHN via multiple mechanisms. Disruption in AHN is associated with both dementia and major depression and microgliosis is a hallmark of several neurodegenerative diseases. Emerging evidence suggests that psychedelics promote neuroplasticity, including neurogenesis, and may also be immunomodulatory. In this context, psilocybin, a serotonergic agonist with rapid-acting antidepressant properties has the potential to ameliorate intersecting pathophysiological processes relevant for both major depression and neurodegenerative diseases. In this narrative review, we focus on the evidence base for the effects of psilocybin on adult hippocampal neurogenesis and microglial form and function; which may suggest that psilocybin has the potential to modulate multiple mechanisms of action, and may have implications in altering the progression from major depression to dementia in those at risk.

Retinal microvascular abnormalities in major depression

BACKGROUND

The aim of our study was to find a possible association between retinal microvascular abnormality and major depression in a non-geriatric population.

METHOD

The participants with major depression were hospitalised at the University Hospital in Hradec Kralove, Department of Psychiatry. Retinal images were obtained using a stationary Fundus camera FF450 by Zeiss and a hand-held camera by oDocs.

RESULTS

Fifty patients (men n=18, women n=32) aged 16 to 55 (men's average age 33.7±9.9 years, women's average age 37.9±11.5 years) were compared with fifty mentally healthy subjects (men n=28, women n=22) aged 18 to 61 (men's average age 35.3±9.2 years, women's average age 36.6±10.6 years) in a cross-sectional design. The patients were diagnosed with a single depressive episode (n=26) or a recurrent depressive disorder (n=24) according to the ICD-10 classification. Our results confirmed significant microvascular changes in the retina in patients with depressive disorder in comparison to the control group of mentally healthy subjects, with significantly larger arteriolar (P<0.0001) as well as venular (P<0.001-0.0001) calibres in major depression.

CONCLUSION

According to the literature, acute and chronic neuroinflammation is associated with changes in microvascular form and function. The endothelium becomes a major participant in the inflammatory response damaging the surrounding tissue and its function. Because the retina and brain tissue share a common embryonic origin, we suspect similar microvascular pathology in the retina and in the brain in major depression. Our results may contribute to a better understanding of depression etiopathogenesis and to its personalized treatment.

The effect of emotion recognition and mindfulness on depression symptoms: A case-control study

Abnormalities in emotion recognition (ER) are frequently reported in depression, with lower recognition accuracy in patients with major depressive disorder (MDD) when compared to healthy individuals. Mindfulness was found to directly impact the severity of depressive symptoms, by recognizing negative cognitions and dysfunctional reactions. The aims of this study were to compare ER and mindfulness levels between MDD patients and healthy controls (HCs), as well as to examine whether ER and mindfulness are related to symptom severity in MDD patients. Sixty-eight patients with MDD and 93 HCs participated in the study. A sociodemographic form, reading the mind in the eyes test (RMET), five facet mindfulness questionnaire-short form (FFMQ-S) and the Montgomery-Asberg depression scale (MADRS) were administered. Group comparison in ER and mindfulness was performed using the multivariate analysis of covariance (MANCOVA). Bivariate correlations and hierarchical linear regression analyses were performed to assess the associations between depression severity, ER and mindfulness in the patient group. Higher level of mindfulness was found in HCs relative to MDD group, however, no ER difference was present between the groups. A positive association between depression severity and the non-reactivity facet of mindfulness was found. On the other hand, ER was not significantly associated with symptom severity among individuals with MDD. Non-reactivity, unlike other dimensions of mindfulness, seems to increase with the severity of depressive symptoms among MDD patients. A particular focus on this subdimension in mindfulness techniques may yield better outcomes in alleviation of depressive symptoms.

The beneficial effect of fluoxetine on behavioral and cognitive changes in chronic experimental Chagas disease unveils the role of serotonin fueling astrocyte infection by Trypanosoma cruzi

BACKGROUND

In Chagas disease (CD), a neglected tropical disease caused by the parasite Trypanosoma cruzi, the development of mental disorders such as anxiety, depression, and memory loss may be underpinned by social, psychological, and biological stressors. Here, we investigated biological factors underlying behavioral changes in a preclinical model of CD.

METHODOLOGY/PRINCIPAL FINDINGS

In T. cruzi-infected C57BL/6 mice, a kinetic study (5 to 150 days postinfection, dpi) using standardized methods revealed a sequential onset of behavioral changes: reduced innate compulsive behavior, followed by anxiety and depressive-like behavior, ending with progressive memory impairments. Hence, T. cruzi-infected mice were treated (120 to 150 dpi) with 10 mg/Kg/day of the selective serotonin reuptake inhibitor fluoxetine (Fx), an antidepressant that favors neuroplasticity. Fx therapy reversed the innate compulsive behavior loss, anxiety, and depressive-like behavior while preventing or reversing memory deficits. Biochemical, histological, and parasitological analyses of the brain tissue showed increased levels of the neurotransmitters GABA/glutamate and lipid peroxidation products and decreased expression of brain-derived neurotrophic factor in the absence of neuroinflammation at 150 dpi. Fx therapy ameliorated the neurochemical changes and reduced parasite load in the brain tissue. Next, using the human U-87 MG astroglioma cell line, we found no direct effect of Fx on parasite load. Crucially, serotonin/5-HT (Ser/5-HT) promoted parasite uptake, an effect increased by prior stimulation with IFNγ and TNF but abrogated by Fx. Also, Fx blocked the cytokine-driven Ser/5-HT-promoted increase of nitric oxide and glutamate levels in infected cells.

CONCLUSION/SIGNIFICANCE

We bring the first evidence of a sequential onset of behavioral changes in T. cruzi-infected mice. Fx therapy improves behavioral and biological changes and parasite control in the brain tissue. Moreover, in the central nervous system, cytokine-driven Ser/5-HT consumption may favor parasite persistence, disrupting neurotransmitter balance and promoting a neurotoxic environment likely contributing to behavioral and cognitive disorders.

Immunotherapy for depression: Recent insights and future targets

Depression stands as a prominent contributor to global disability, entailing an elevated risk of suicide. Substantial evidence supports the notion that immune dysregulation may play a role in the development of depression and impede responses to antidepressant treatments. Immune dysregulation may cause depression in susceptible individuals through raising inflammatory responses. Differences in immune cell types and the release of pro-inflammatory mediators are observed in the blood and cerebrospinal fluid of patients with major depressive disorder, which is associated with neuroimmune dysfunction. Therefore, the interaction of peripheral and central immune targets in depression needs to be understood. Urgent attention is required for the development of innovative therapeutics directed at modulating immune responses for the treatment of depression. This review delineates the immune mechanisms involved in the pathogenesis of depression, assesses the therapeutic potential of immune system targeting for depression treatment, and deliberates on the merits and constraints of employing immunotherapy in the management of depression.

Association and biological pathways between lung function and incident depression: a prospective cohort study of 280,032 participants

BACKGROUND

Lung health is increasingly recognized as an essential factor in mental health. However, prospective evidence on lung function with incident depression remains to be determined. The study aimed to examine the prospective association between impaired lung function and incident depression and the underlying biological mechanisms.

METHODS

This prospective cohort study comprised 280,032 non-depressed individuals with valid lung function measurements from the UK Biobank. Lung function was assessed through the forced vital capacity (FVC) or forced expiratory volume in 1 s (FEV1). Cox proportional hazard models were applied to estimate the associations between lung function and incident depression. Mediation analyses were fitted to investigate the potential mediating role of biomarkers and metabolites in the association.

RESULTS

A total of 9514 participants (3.4%) developed depression during a median follow-up of 13.91 years. Individuals in the highest quartile had a lower risk of depression (FVC % predicted: HR = 0.880, 95% CI = 0.830-0.933; FEV1% predicted: HR = 0.854, 95% CI = 0.805-0.905) compared with those in the lowest quartile of the lung function indices. Additionally, the restricted cubic splines suggested lung function indices had reversed J-shaped associations with incident depression (nonlinear P < 0.05 for FVC % predicted and FEV1% predicted). Impaired lung function yielded similar risk estimates (HR = 1.124, 95% CI = 1.074-1.176). Biomarkers involving systemic inflammation, erythrocytes, and liver and renal function may be potential mediators in the lung function-depression association.

CONCLUSIONS

This study revealed that the higher risk of developing depression was associated with impaired lung function. Also, the association might be partially mediated by biomarkers including systemic inflammation, erythrocytes, and liver and renal function, though these mediation findings should be interpreted with caution due to potential temporal ambiguity.

A Novel Anti-Inflammatory Formulation Comprising Celecoxib and Cannabidiol Exerts Antidepressant and Anxiolytic Effects

Background: Ample research shows that anti-inflammatory drugs, particularly celecoxib, exert antidepressant effects, especially in patients with microglia activation. However, substantial cardiovascular adverse effects limit celecoxib's usefulness. Given that cannabidiol (CBD) exerts anti-inflammatory, microglia-suppressive, and antidepressant effects, we hypothesized that it may potentiate the therapeutic effects of celecoxib. Methods: The effects of celecoxib, CBD, and their combination were examined in murine models of antidepressant- and anxiolytic-like behavioral responsiveness, including the forced swim test (FST), elevated plus maze (EPM), lipopolysaccharide (LPS)-induced neuroinflammation, and chronic social defeat stress (CSDS), as well as in microglia cell cultures. Results: Acute administration of a combination of celecoxib plus CBD, at doses that had no effects by themselves (10 and 5 mg/kg, respectively), produced significant antidepressant- and anxiolytic-like effects in the FST and EPM, in male and female mice. In the LPS model, combinations of celecoxib (10 or 20 mg/kg) plus CBD (30 mg/kg) reversed the anxiety-like behavior in the open-field test (OFT) and anhedonia in the sucrose preference test (SPT), with minimal effects of celecoxib or CBD by themselves. In the CSDS paradigm, a combination of celecoxib plus CBD (each at 30 mg/kg) reversed the deficits in the OFT, EPM, social exploration, and SPT, whereas celecoxib or CBD by themselves had partial effects. In BV2 microglia cultures stimulated with LPS or α-synuclein, CBD markedly potentiated the suppressive effects of celecoxib over TNFα (tumor necrosis factor-α) and IL (interleukin)-1β secretion. Conclusions: Combinations of celecoxib plus CBD produce efficacious antidepressant- and anxiolytic-like effects, which may depend on their synergistic microglia-suppressive effects.

Metabolomics approach for predicting stomach and colon contents in dead Arctocephalus pusillus pusillus, Arctocephalus tropicalis, Lobodon carcinophaga and Ommatophoca rossii from sub-Antarctic region

The dietary habits of seals play a pivotal role in shaping management and administration policies, especially in regions with potential interactions with fisheries. Previous studies have utilized various methods, including traditional approaches, to predict seal diets by retrieving indigestible prey parts, such as calcified structures, from intestines, feces, and stomach contents. Additionally, methods evaluating nitrogen and stable isotopes of carbon have been employed. The metabolomics approach, capable of quantifying small-scale molecules in biofluids, holds promise for specifying dietary exposures and estimating disease risk. This study aimed to assess the diet composition of five seal species-Arctocephalus pusillus pusillus, Lobodon carcinophaga, Ommatophoca rossii, and Arctocephalus tropicalis 1 and 2-by analyzing stomach and colon contents collected from stranded dead seals at various locations. Metabolite concentrations in the seal stomach and colon contents were determined using Nuclear Magnetic Resonance Spectroscopy. Among the colon and stomach contents, 29 known and 8 unknown metabolites were identified. Four metabolites (alanine, fumarate, lactate, and proline) from stomach contents and one metabolite (alanine) from colon contents showed no significant differences between seal species (p>0.05). This suggests that traces of these metabolites in the stomach and colon contents may be produced by the seals' gut microbiome or derived from other animals, possibly indicating reliance on fish caught at sea. Despite this insight, the cause of death for stranded seals remains unclear. The study highlights the need for specific and reliable biomarkers to precisely indicate dietary exposures across seal populations. Additionally, there is a call for the development of relevant metabolite and disease interaction networks to explore disease-related metabolites in seals. Ultimately, the metabolomic method employed in this study reveals potential metabolites in the stomach and colon contents of these seal species.

CTLA-4 expression and polymorphisms in Schizophrenia; a systematic review of literature

Schizophrenia constitutes a severe psychiatric disorder with detrimental impacts on individuals, their support systems, and the broader economy. Extensive research has revealed a notable association between variations in the Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) gene and an increased susceptibility to schizophrenia.This study represents the first systematic review of the literature investigating the impact of CTLA-4 polymorphisms and expression on the development and progression of schizophrenia.Our investigation involved a comprehensive search strategy, using a combination of title, abstract, and MESH terms in four databases, including PubMed, Scopus, Web of Science, and Google Scholar, until August 29th, 2023. The complete texts of the identified records were obtained and rigorously assessed based on predefined exclusion and inclusion criteria. Out of the numerous records, a total of 88 were identified through the databases. 10 studies met the criteria; therefore, their quality was assessed and included in this systematic study. The records were then categorized into polymorphism and expression groups. Our investigation emphasizes an association between rs3087243, rs231779, rs231777, rs16840252, rs5742909, and rs231775 polymorphisms and the development of schizophrenia. The results demonstrate a correlation between CTLA-4 polymorphisms and schizophrenia, compelling the need for further research to thoroughly examine the role of CTLA-4 in schizophrenia and other psychiatric disorders.

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

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

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 .