The effect of inflammation markers on cortical thinning in major depressive disorder: A possible mediator of depression and cortical changes

Mediating effects of gastroesophageal reflux disease and smoking behavior on the relationship between depression and chronic obstructive pulmonary disease: Trans-ethnic Mendelian randomization study

BACKGROUND

This study seeks to elucidate the association between depression and the risk of chronic obstructive pulmonary disease (COPD) by Mendelian randomization (MR) analysis, motivated by prior observational studies indicating a potential link between these conditions.

METHODS

Data from individuals of European (EUR) and East Asian (EAS) ancestries diagnosed with major depressive disorder (MDD) were selected for analysis. The primary method utilized was inverse variance weighted (IVW) method, supplemented by a series of sensitivity analyses and false discovery rate (FDR) corrections. Subsequently, multivariable and mediation MR analyses were conducted to assess the impact of potential confounders and their mediating effects.

RESULTS

IVW revealed a significant causal relationship between MDD and COPD within EUR ancestry (OR 1.425, 95 % CI 1.243-1.633, P = 3.56 × 10-7, PFDR = 2.14 × 10-6). Additionally, replication datasets provided consistent evidence for these causal associations. Multivariable and mediation MR analyses identified gastroesophageal reflux disease (GORD) as a complete mediator (mediation effect: 98.97 %, P = 1.38 × 10-15), while smoking initiation (SI) (26.30 %, 5.54 × 10-9), age of smoking initiation (ASI) (18.73 %, 0.019), and cigarettes per day (CPD) (18.72 %, 0.004) were identified as partial mediators of this causal relationship. No causal association was detected in EAS ancestry, nor was reverse analysis.

CONCLUSIONS

This study established a causal relationship between MDD and COPD risk in EUR ancestry, identifying GORD and smoking as pivotal mediators. Future research involving larger cohorts is essential to validate the generalizability of these findings across other ancestries.

Mediating effect of pro-inflammatory cytokines in the association between depression, anxiety, and cardiometabolic disorders in an ethnically diverse community-dwelling middle-aged and older US population

Introduction

Neuroinflammation is associated with depression and anxiety risk, both of which demonstrate a bilateral relationship with cardiometabolic disorders. Systemic inflammation is also commonly described in patients with cardiometabolic disorders. It is, thus, unclear whether pro-inflammatory cytokines might mediate the relationship between depression, anxiety, and cardiometabolic disorders, particularly in advanced ages.

Methods

The multiethnic ≥ 50-year-old study population is a subset of the Health and Aging Brain Study: Health Disparities (HABS-HD). Adjusted logistic and linear regression models were applied to assess associations. Non-linearity was evaluated using restricted cubic splines. Statistical mediation analysis was used to determine the role of inflammation (Tumor Necrosis Factor-alpha (TNF-alpha) and Interleukin-6 (IL-6)). Models were corrected for multiple testing using the False Discovery Rate (FDR)-method.

Results

In the 2,093 included cases, depression and/or anxiety were significantly associated with 62% higher odds of Cardiovascular Disorder (CVD) (OR=1.62 [95% CI: 1.22-2.15]), 54% of type 2 diabetes (T2DM) (OR=1.54 [95% CI: 1.29-1.85]), 26% of hypertension (OR=26% [95% CI: 1.07-1.48]), and 29% of obesity (OR=1.29 [95% CI: 1.11-1.51]).Only IL-6 showed a significant mediating role in the association of depression and/or anxiety with CVD (10%, p-value FDR =0.016), T2DM (13%, p-value FDR <0.001), hypertension (16%, p-value FDR <0.001), and obesity (23%, p-value FDR <0.001).

Conclusions

Depression and anxiety were significantly associated with higher odds of major cardiometabolic disorders, and IL-6 partly mediated these associations. Clinical studies are needed to replicate the findings and specifically cluster high-risk profiles.

Inflammation-related abnormal dynamic brain activity correlates with cognitive impairment in first-episode, drug-naïve major depressive disorder

BACKGROUND

Cognitive impairment is common in major depressive disorder (MDD) and potentially linked to inflammation-induced alterations in brain function. However, the relationship between inflammation, dynamic brain activity, and cognitive impairment in MDD remains unclear.

METHODS

Fifty-seven first-episode, drug-naïve MDD patients and sixty healthy controls underwent fMRI scanning. Dynamic amplitude of low-frequency fluctuations (dALFF) and dynamic functional connectivity (dFC) were measured using the sliding window method. Plasma IL - 6 levels and cognitive function were assessed using enzyme-linked immunosorbent assay (ELISA) and the Repeated Battery for Assessment of Neuropsychological Status (RBANS), respectively.

RESULTS

MDD patients exhibited decreased dALFF in the bilateral inferior temporal gyrus (ITG), right inferior frontal gyrus, opercular part (IFGoperc), and bilateral middle occipital gyrus (MOG). Regions of dALFF associated with IL-6 included right ITG (r = -0.400/p = 0.003), left ITG (r = -0.381/p = 0.004), right IFGoperc (r = -0.342/p = 0.011), and right MOG (r = -0.327/p = 0.016). Furthermore, IL-6-related abnormal dALFF (including right ITG: r = 0.309/p = 0.023, left ITG: r = 0.276/p = 0.044) was associated with attention impairment. These associations were absent entirely in MDD patients without suicidal ideation. Additionally, IL-6 levels were correlated with dFC of specific brain regions.

LIMITATIONS

Small sample size and cross-sectional study design.

CONCLUSIONS

Inflammation-related dALFF was associated with attention impairment in MDD patients, with variations observed among MDD subgroups. These findings contribute to the understanding of the intricate relationship between inflammation, dynamic brain activity and cognitive impairments in MDD.

Neurobiology and medico-legal aspects of suicides among older adults: a narrative review

The task of preventing suicide in older adults is an important social burden as older adults aged above 65 are exposed to singular psychological aspects that increase suicide risks. Moreover, when an older adult corpse is found, the medico-legal inspection represents a fundamental tool to identify the exact cause of death, classifying or excluding it as suicide. In this scenario, this review aims to explore the neurobiological factors that could be related to suicidal behavior in older adults. A further goal of this review is the exploration of the medico-legal aspects surrounding older adult suicides, clarifying the importance of forensic investigation. Particularly, this review examines issues such as neurotransmitter imbalances, cognitive impairment, neuroinflammation, psychosocial factors related to geriatric suicide, and neurodegenerative diseases. Additionally, medico-legal aspects such as policy considerations, legal frameworks, mental health assessments, ethical implications and forensic investigation were explored. Considering the importance of this phenomenon, especially in western countries, a need has emerged for focused screening tools on suicidal behavior among older adults, in order to contain it. Therefore, this review makes an exhaustive appraisal of the literature giving insights into the delicate interplay between neurobiology as well as mental health in relation to older adult suicide within a medico-legal context. The comprehension of different aspects about this complex phenomenon is fundamental to propose new and more effective interventions, supporting tailored initiatives such as family support and improving healthcare, specifically towards vulnerable ageing societies to reduce older adult suicide risks.

PI3K/AKT signaling pathway: Molecular mechanisms and therapeutic potential in depression

Depression is a serious global mental disorder. Numerous studies have found that depression may be closely related to decreased neurogenesis, neuroinflammation, neurotransmitter imbalance, and synaptic plasticity dysfunction. The pathogenesis of depression is complex and involves multiple signal transduction pathways and molecular changes. The PI3K/AKT pathway is an essential signaling pathways in neurons, which is widely expressed in emotion-related regions of the brain. Therefore, the PI3K/AKT pathway may play a moderating role in mood disorders. However, the role and mechanism of the PI3K/AKT signaling pathway in depression have not been fully described. This review systematically summarized the role of the PI3K/AKT signaling pathway in the pathogenesis of depression and discussed its potential in the treatment of depression. This will help in the treatment of depression and the development of antidepressants.

Neural Functioning in Late-Life Depression: An Activation Likelihood Estimation Meta-Analysis

Late-life depression (LLD) is a relatively common and debilitating mental disorder, also associated with cognitive dysfunctions and an increased risk of mortality. Considering the growing elderly population worldwide, LLD is increasingly emerging as a significant public health issue, also due to the rise in direct and indirect costs borne by healthcare systems. Understanding the neuroanatomical and neurofunctional correlates of LLD is crucial for developing more targeted and effective interventions, both from a preventive and therapeutic standpoint. This ALE meta-analysis aims to evaluate the involvement of specific neurofunctional changes in the neurophysiopathology of LLD by analysing functional neuroimaging studies conducted on patients with LLD compared to healthy subjects (HCs). We included 19 studies conducted on 844 subjects, divided into 439 patients with LLD and 405 HCs. Patients with LLD, compared to HCs, showed significant hypoactivation of the right superior and medial frontal gyri (Brodmann areas (Bas) 8, 9), left cingulate cortex (BA 24), left putamen, and left caudate body. The same patients exhibited significant hyperactivation of the left superior temporal gyrus (BA 42), left inferior frontal gyrus (BA 45), right anterior cingulate cortex (BA 24), right cerebellar culmen, and left cerebellar declive. In summary, we found significant changes in activation patterns and brain functioning in areas encompassed in the cortico-limbic-striatal network in LLD. Furthermore, our results suggest a potential role for areas within the cortico-striatal-cerebellar network in the neurophysiopathology of LLD.

Assessing causality between chronic obstructive pulmonary disease with depression: A bidirectional Mendelian randomization study

PURPOSE

Our investigation utilized a two-sample Mendelian randomization approach to explore the ambiguous bidirectional relationship between Chronic Obstructive Pulmonary Disease (COPD) and depression, furthering insights from existing observational studies.

METHODS

In this study, we conducted a bidirectional Mendelian randomization using genome-wide association studies (GWAS) datasets. We initially analyzed depression data from the Psychiatric Genomics Consortium and the UK Biobank (n = 500,199), alongside COPD data from the FinnGen Consortium (n = 329,552). The second phase involved comparing depression data from FinnGen (n = 372,472) with COPD data from the UK Biobank (n = 361,194). Our Mendelian analysis employs various methods to guarantee a comprehensive and rigorous investigation.

RESULTS

In the initial analytic phase utilizing the inverse variance weighted (IVW) method, COPD does not significantly contribute to the incidence of depression (IVW odds ratio (OR) = 0.989, 95 % confidence interval (CI) = 0.895 to 1.092, P = 0.824). Conversely, the data suggested a statistically significant association where depression may precipitate the development of COPD, with a notable increase in risk (IVW OR = 1.421, 95 % CI = 1.149 to 1.756, P = 0.001). Subsequent validation through a second-step analysis reinforced the hypothesis that depression elevates the likelihood of COPD onset (IVW OR = 1.002, 95 % CI = 1.0003 to 1.0046, P = 0.028).

CONCLUSION

Our study, utilizing Mendelian randomization analysis, determined that COPD does not escalate the risk of depression. Conversely, our analysis suggests that depression may elevate the risk of developing COPD. This insight underscores the importance of enhancing prevention, screening, and treatment strategies for COPD in individuals with depression.