Linking atypical depression and insulin resistance-related disorders via low-grade chronic inflammation: Integrating the phenotypic, molecular and neuroanatomical dimensions

Association of aberrant gray matter neurite density with neurovegetative symptom in atypical depression

BACKGROUND

The heterogeneity of symptoms in major depressive disorder is impeding progress toward patient-specific treatment strategies and course trajectories. Origins of such differential clinical manifestations likely have dissociable pathophysiologies, but neural substrates associated with specific atypical depressive symptoms remain elusive.

METHODS

The muti-shell diffusion MRI images were acquired from 50 patients with atypical depression (AD), 97 patients with non-atypical depression (non-AD), and 50 healthy controls (HCs). We used gray matter-specific multi-compartment diffusion models (cortical-neurite orientation dispersion and density imaging and free-water elimination model) to assess abnormalities of gray matter microstructure associated with AD. Superficial U-fibers analysis was performed to clarify short-range cortico-cortical connections.

RESULTS

Abnormalities in intracellular volume fraction (ICVF) and free-water fraction anisotropy were found in the superior frontal gyrus, middle frontal gyrus, inferior parietal gyrus, and superior parietal gyrus across three groups. Post-hoc pairwise comparative analysis yielded similar results. While adjusting for the effects of age, gender, education, and the ICVF mentioned above, AD patients showed significantly higher scores in reversed neurovegetative symptoms and leaden paralysis compared with non-AD patients. Moreover, diagnosis-related alterations in ICVF of right caudal middle frontal gyrus and education-related changes in ICVF of right superior frontal gyrus were significantly associated with hypersomnia. We also found that underlying superficial U-fibers reflected deficits in cortical-derived neurite density.

CONCLUSIONS

Cortical-derived neurite density abnormalities were significantly associated with atypical depressive symptoms, capturing interindividual etiological heterogeneity in patients with major depressive disorder. Cortical-derived neurite density within the medial prefrontal gyrus may be a robust biomarker for atypical depressive symptoms of AD.

Differential patterns of axonal loss associated with threat-related adversity in atypical depression and non-atypical depression

BACKGROUND

Major depressive disorder (MDD) encompasses a broad spectrum of heterogeneous symptoms arising from distinct etiological mechanisms. Phenotypic markers of psychopathology are most likely influenced by exposure to childhood maltreatment, yielding distinct subtypes within conventional diagnostic boundaries. However, the biological interactions between MDD subtypes and types of childhood trauma remain unclear.

METHODS

50 atypical depression (AD) patients, 97 non-AD patients and 50 healthy controls were included to complete multi-shell diffusion MRI scans and clinical assessments. Differential tractography was performed to clarify the axonal injury between the AD and non-AD groups. Moreover, correlational tractography was employed to individually assess the relationship between quantitative anisotropy (QA) and all types of childhood trauma in each depressed subgroup.

RESULTS

Our study found that AD and non-AD patients had differential axonal loss primarily involving the bilateral superior longitudinal fasciculus, arcuate fasciculus, inferior longitudinal fasciculus, parietal aslant tract, and corpus callosum. Furthermore, AD patients showed significantly negative associations between QA values, childhood trauma total scores, and threat-related adversity, while significantly positive associations were observed in non-AD patients. However, similar phenomena were not observed for deprivation-related adversities.

DISCUSSION

Our findings indicate differential spatial patterns of axonal alterations associated with threat-related adversity in atypical depression and non-atypical depression. Efforts to attenuate the consequences of childhood maltreatment for MDD should consider the associations between specific patterns of adversity and specific clinical manifestations.

Association between peripheral inflammation and body mass index on white matter integrity and free water in bipolar II depression

Immuno-metabolic dysregulation is implicated in mood disorders and elucidating non-invasive brain correlates may aid clinical translation of pathomechanism. This study aims to investigate the interrelationship between peripheral inflammation and body mass index (BMI) and their effects on white matter (WM) microstructure and free water (FW) in bipolar II depression (BDII-D). Voxel-wise FW and FW-corrected fractional anisotropy (FAt) were compared between 146 BDII-D and 151 healthy controls (HCs) using FSL Randomise. Partial correlations were used to explore associations between BMI, peripheral inflammation, FW measures, and psychiatric symptoms. Moderation analysis examined the interrelationships among BMI, peripheral inflammation, and FW measures. BDII-D showed lower FAt in the genu of the corpus callosum (CC) and bilateral anterior corona radiata, and higher FW in the body of the CC compared with HCs. Higher BMI was linked to lower global FAt (q < 0.001), while higher peripheral inflammation was associated with higher global FW (q ≤ 0.01) in BDII-D. Lower FAt in the genu of the CC and higher FW in the body of CC were significantly related to higher BMI, inflammation, and greater depressive symptoms (q < 0.05). Low-grade Inflammation moderated the relationship between higher BMI and lower FAt in the genu of the CC in BDII-D (B = -3.094e-05, p < 0.001). We found evidence for a mechanistic link between immune-metabolic dysregulation and altered connection in BDII-D. Next to mediating BMI effects on WM integrity, there seems to exist specific relationships between inflammation and BMI with different MR-based tract markers that need further investigation.

Inflammation and metabolic dysfunction underly anhedonia-like behavior in antidepressant resistant male rats

Inflammation and metabolic dysfunction impair dopamine neurotransmission, which is thought to serve as a critical mechanism underpinning motivational deficits such as anhedonia across a range of psychiatric and neurological disorders. This difficult-to-treat transdiagnostic symptom has important implications for treatment resistant depression (TRD), and may warrant more targeted therapeutic approaches that address the underlying pathophysiological mechanisms. Using the adrenocorticotrophic hormone (ACTH) model of antidepressant treatment resistance we characterized the relationship between antidepressant-like and anhedonia-like behavioral responses to bupropion, mesocortical tyrosine hydroxylase (TH) expression, chronic low-grade inflammation, and metabolic changes in male rats. We demonstrate that chronic ACTH elicited both an antidepressant resistant- and anhedonia-like phenotype in forced swim and effort-related choice behavioral tasks, respectively. This was associated with decreased TH expression in the brain, increased central and peripheral markers of inflammation, and peripheral metabolic disturbances, including impairment of immune cell insulin action. Multivariate analysis revealed that peripheral interleukin-6 (IL-6) levels, immune cell glucose uptake and disturbance of nucleotide metabolism were strongly associated with anhedonia-like behavior. Post-hoc analyses further confirmed strong correlations between TH expression, inflammation and behavioral performance. These data suggest that stress hormone-induced upregulation of inflammation concurrent with the impairment of insulin-mediated glucose uptake into immune cells is associated with disruption of nucleotide metabolism, and potential impaired central dopamine synthesis contributing to the behavioral expression of anhedonia. These results suggest that immunometabolic perturbations concomitant with impaired insulin action at the level of the immune cell result in a metabolically deficient state that directly impacts nucleotide precursors essential for dopamine synthesis and effortful behavior. These results highlight the potential for immune and metabolic markers for individualized treatment of refractory depression and anhedonia.

Preliminary exploration of the association of CXCR6+T lymphocytes in T2D

Type 2 diabetes (T2D) is a metabolic disease, in which inflammation is a key factor. It has been well established that T cells play important role in antigen-driven immune disorders or immune defense, but were less discussed in inflammatory metabolic diseases. However, accumulating evidences suggest that CD186 (also known as CXCR6)-positive tissue infiltrating T cells might play a key role in inflammatory metabolic diseases. Here, as a preliminary and exploratory study, we detected the expression levels of CXCR6 on peripheral blood T-lymphocytes of human subjects of T2D. Additionally, the expression levels of CXCR6 in BSK-db/db mice, a murine T2D model, were also detected. Results showed that, compared with the healthy control group, T2D group had significantly reduced levels of CD4+CD45RO-CD186+CD183- T lymphocytes (Z = -3.988, P < 0.001) and CD8+CD45RO+CD186+CD183- T lymphocytes (Z = -2.428, P = 0.035). CD4+CD45RO-CD186+CD183- T lymphocytes had an AUC area of 0.978 (0.93, 1.00), 88.9 % sensitivity, and 100.0 % specificity. Additionally, the sensitivity of CD8+CD45RO+CD186+CD183- was 55.6 %, and the specificity was 100.0 %, with an AUC area of 0.747 (0.522, 0.972). The levels of CD8+CD186+ (t = -3.198, P = 0.015), CD8+CD44+CD186+ (t = -2.706, P = 0.030), and CD8+CD44-CD186+ (t = -2.915, P = 0.022) in BSK-db/db mice were significantly lower than in BSK-db/db homologous control mice. Taken together, CXCR6+T cells might play a role in T2D, and has the potential to become a biomarker for T2D patients.

Investigating the role of GPR39 in treatment of stress-induced depression and anxiety

RATIONALE

Chronic stress is one of the leading causes of depression. Yet, knowledge of the pathomechanism of this process still eludes us. Chronic unpredictable mild stress (CUMS) model of depression enables researchers to look for a root cause of the disease in mice by mimicking a stressful human environment.

OBJECTIVE

Since zinc has already been shown to impact the treatment of depression, in our study we aimed to shed light on the role of the zinc receptor GPR39 in stress-induced depression. We also aimed to highlight the role of GPR39 activation in monoamine-based antidepressant treatment.

METHODS

Using large battery of behavioural tests, we provided a detailed description of CUMS-induced phenotype in both - CD-1 and GPR39 knock-out mice.

RESULTS

Our experiments showed that combined treatment with TC-G 1008 (GPR39 agonist) and antidepressants produces stronger antidepressant-like effect of classic antidepressants. We also demonstrated the inter-strain differences in stress response and the greater stress susceptibility of GPR39 knock-out mice. The lack of GPR39 expression also either diminished or completely abolished the response to treatment with different antidepressants combined with TC-G 1008.

CONCLUSIONS

The results show that GPR39 KO mice are more susceptible to chronic stress and that they are non-responsive to SSRI treatment. Utilizing various behavioural tests gave us much broader understanding not only of the role of GPR39 in depression treatment, but also of the importance of detailed behavioural description in a proper interpretation of the results. Further research with known selective agonists and antagonists of GPR39 will be necessary to understand the full potential of this receptor as a pharmacological target.

The association between lipid accumulation products and depression in U.S. adults: A cross-sectional study from NHANES 2005-2018

OBJECTIVE

The purpose of this study was to investigate the correlation between lipid accumulation products (LAP) and depression among adults in the United States.

METHODS

We analyzed data from 13,051 persons participating in the NHANES 2005-2018 cycle. The LAP index was calculated using the waist circumference (WC) and serum triglyceride (TG) levels, which reflect lipid toxicity. Participants who scored ≥10 on the Patient Health Questionnaire-9 (PHQ-9) were considered depressed. Multivariate logistic regression analyses were conducted to explore the association between the LAP index and depression. Subgroup analysis was also conducted to identify sensitive populations. Smoothed curve fitting and generalized additive model (GAM) regression were performed to verify the association between the LAP index and depression.

RESULTS

After adjusting for all potential confounders, the risk of depression increased with increasing LAP index (odds ratio [OR]=1.0011, 95% confidence interval [CI]= 1.0001-1.0021). Compared to participants in LAP quartile 1, participants in LAP quartile 3 exhibited the highest risk for depression (OR=1.43, 95% CI: 1.03-1.99). Subgroup analysis demonstrated a stronger association between the LAP index and depression in men (OR= 1.002, 95% CI= 1.001-1.004) and in those with hypertension (OR=1.002, 95% CI=1.000-1.003). Additionally, smoothed curve fitting and GAM regression demonstrated a positive linear correlation between the LAP index and depression.

CONCLUSIONS

These findings suggest that individuals with a higher LAP index may be at greater risk for depression, particularly among men and those with hypertension. Further studies are required to confirm these findings.

Dissecting shared genetic architecture between depression and body mass index

BACKGROUND

A growing body of evidence supports the comorbidity between depression (DEP) and obesity, yet the genetic mechanisms underlying this association remain unclear. Our study explored the shared genetic architecture and causal associations of DEP with BMI.

METHODS

We investigated the multigene overlap and genetic correlation between DEP (N > 1.3 million) and BMI (N = 806,834) based on genome-wide association studies (GWAS) and using the bivariate causal mixture model and linkage disequilibrium score regression (LDSC). The causal association was explored by bi-directional Mendelian randomization (MR). Common risk loci were identified through cross-trait meta-analyses. Stratified LDSC and multi-marker gene annotation analyses were applied to investigate single-nucleotide polymorphisms enrichment across tissue types, cell types, and functional categories. Finally, we explored shared functional genes by Summary Data-Based Mendelian Randomization (SMR) and further detected differential expression genes (DEG) in brain tissues of individuals with depression and obesity.

RESULTS

We found a positive genetic correlation between DEP and BMI (rg = 0.19, P = 4.07 × 10-26), which was more evident in local genomic regions. Cross-trait meta-analyses identified 16 shared genetic loci, 5 of which were newly identified, and they had influence on both diseases in the same direction. MR analysis showed a bidirectional causal association between DEP and BMI, with comparable effect sizes estimated in both directions. Combined with gene expression information, we found that genetic correlations between DEP and BMI were enriched in 6 brain regions, predominantly in the nucleus accumbens and anterior cingulate cortex. Moreover, 6 specific cell types and 23 functional genes were found to have an impact on both DEP and BMI across the brain regions. Of which, NEGR1 was identified as the most significant functional gene and associated with DEP and BMI at the genome-wide significance level (P < 5 × 10-8). Compared with healthy controls, the expression levels of NEGR1 gene were significant lower in brain tissues of individuals with depression and obesity.

CONCLUSIONS

Our study reveals shared genetic basis underpinnings between DEP and BMI, including genetic correlations and common genes. These insights offer novel opportunities and avenues for future research into their comorbidities.

CD177 on neutrophils engages stress-related behavioral changes in male mice

Persistent psychological stress can affect immune homeostasis and is a key factor in the development of depression. Many efforts are focused on the identifcation of pathways that link the immune system and mood disorders. Here, we found that psychological stress caused an increase in the frequency of brain-associated neutrophils and the level of neutrophil-specific antigen CD177 on peripheral neutrophils in male mice. Upregulated levels of blood CD177 are associated with depression in humans. Neutrophil depletion or Cd177 deficiency protected mice from stress-induced behavioral deficits. Importantly, adoptive transfer of CD177+ neutrophils from stressed mice increased the frequency of brain-associated leukocytes, including neutrophils, and caused behavioral defects in naive mice. These effects may be related to the endothelial adhesion advantage of CD177+ neutrophils and the interference of serine protease on endothelial junction. Our findings suggest a critical link between circulating CD177+ neutrophils and psychological stress-driven behavioral disorder.

The relationship between depression and lipid accumulation product: a population-based study

Background

Lipid Accumulation Product (LAP) is a new type of obesity index. The relationship between LAP and depression is unclear, and this cross-sectional study was conducted to explore the relationship between LAP and depression using the National Health and Nutrition Examination Survey (NHANES) database from 2005-2018.

Methods

In our study, logistic regression analysis was used to calculate the odds ratio between depression and LAP, and subgroup analysis and sensitivity analysis were also performed to verify the robustness of the results.

Results

The analysis included 13,240 participants aged 20 years or older. After adjusting for multiple variables, LAP was positively associated with depression, OR 1. 50 (95% CI, 1. 05-2. 12). In subgroup analysis, LAP was significantly positively, associated with depression among male (2. 52, OR; 95% CI, 1. 39,4. 57), non-Hispanic Black (2. 55, OR; 95% CI, 1. 49,4. 36), those without diabetes (1. 67, OR; 95% CI, (1. 06,2. 61) or in the overweight (2. 09, OR; 95% CI, (1. 23,3. 54) subgroups. After inverse probability of treatment weighting (IPTW), the OR for the highest versus lowest quartile was 1. 55 (95% CI: 1. 24 - 1. 95).

Conclusion

There are positive results between LAP and depression after adjusting for multiple potential variables, and prospective studies are needed to verify the results.

Joint associations among non-essential heavy metal mixtures and nutritional factors on glucose metabolism indexes in US adults: evidence from the NHANES 2011-2016

Dietary intake can modify the impact of metals on human health, and is also closely related to glucose metabolism in human bodies. However, research on their interaction is limited. We used data based on 1738 adults aged ≥20 years from the National Health and Nutrition Examination Survey 2011-2016. We combined linear regression and restricted cubic splines with Bayesian kernel machine regression (BKMR) to identify metals associated with each glucose metabolism index (P < 0.05 and the posterior inclusion probabilities of BKMR >0.5) in eight non-essential heavy metals (barium, cadmium, antimony, tungsten, uranium, arsenic, lead, and thallium) and glucose metabolism indexes [fasting plasma glucose (FPG), blood hemoglobin A1c (HbA1c) and homeostatic model assessment of insulin resistance (HOMA-IR)]. We identified two pairs of metals associated with glucose metabolism indexes: cadmium and tungsten to HbA1c and barium and thallium to HOMA-IR. Then, the cross-validated kernel ensemble (CVEK) approach was applied to identify the specific nutrient group (nutrients) that interacted with the association. By using the CVEK model, we identified significant interactions between the energy-adjusted diet inflammatory index (E-DII) and cadmium, tungsten and barium (all P < 0.05); macro-nutrients and cadmium, tungsten and barium (all P < 0.05); minerals and cadmium, tungsten, barium and thallium (all P < 0.05); and A vitamins and thallium (P = 0.043). Furthermore, a lower E-DII, a lower intake of carbohydrates and phosphorus, and a higher consumption of magnesium seem to attenuate the positive association between metals and glucose metabolism indexes. Our finding identifying the nutrients that interact with non-essential heavy metals could provide a feasible nutritional guideline for the general population to protect against the adverse effects of non-essential heavy metals on glucose metabolism.

New insights into the interaction between polycystic ovary syndrome and psychiatric disorders: A narrative review

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disease characterized by hyperandrogenism, ovulatory dysfunction, and ovarian polycystic changes, which combines with reproductive problems, metabolic disorders, and psychological disorders to exhibit a far-reaching impact on the physical and mental health of women. We reviewed previous research and discovered that psychiatric disorders are more common in PCOS patients and their children, potentially exacerbating the condition and creating a vicious loop. To understand the reasons, relevant articles were collected following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines from PubMed, Web of Science, and Cochrane Library, through December 2022. Evidence suggested that PCOS-related clinical manifestations, hyperandrogenism, insulin resistance, obesity, gut dysbiosis, and other variables may increase the risk of psychiatric disorders in patients. In turn, psychiatric disorders may aggravate the pathologic process of PCOS and increase the difficulty of the treatment. We systematically reported the mechanisms underlying the psychiatric disorders-PCOS interactions, intending to provide potential ways to break the vicious cycle and lay the groundwork for future research. However, research on PCOS and psychiatric disorders were still in initial stages, which limited the scope of this review. More studies are needed to further verify our findings.

The molecular mechanism of polysaccharides in combating major depressive disorder: A comprehensive review

Major depressive disorder (MDD) is a complex psychiatric condition with diverse etiological factors. Typical pathological features include decreased cerebral cortex, subcortical structures, and grey matter volumes, as well as monoamine transmitter dysregulation. Although medications exist to treat MDD, unmet needs persist due to limited efficacy, induced side effects, and relapse upon drug withdrawal. Polysaccharides offer promising new therapies for MDD, demonstrating antidepressant effects with minimal side effects and multiple targets. These include neurotransmitter, neurotrophin, neuroinflammation, hypothalamic-pituitary-adrenal axis, mitochondrial function, oxidative stress, and intestinal flora regulation. This review explores the latest advancements in understanding the pharmacological actions and mechanisms of polysaccharides in treating major depression. We discuss the impact of polysaccharides' diverse structures and properties on their pharmacological actions, aiming to inspire new research directions and facilitate the discovery of novel anti-depressive drugs.

Lower extremity arterial plaque in patients with type 2 diabetes mellitus: A cross-sectional study of 25-(OH)D3 and other risk factors

OBJECTIVE

The occurrence of chronic vascular complications in individuals with type 2 diabetes mellitus(T2DM) is influenced by multiple factors. This study aims to analyze the correlation between serum 25-(OH)D3 levels and other risk factors with the formation and severity of arterial plaques in the lower extremities, and explore its role in clinical diagnosis and treatment.

METHODS

A total of 628 Chinese patients with T2DM were included in this study. Based on the intima-media thickness (IMT) and plaque echogenicity measured by lower extremity vascular ultrasound, the patients were divided into the no plaque group(NP), low-risk plague group(LP), moderate-risk plague group(MP), and severe-risk plague group(SP). Based on 25-(OH)D3 levels, patients were categorized as vitamin D deficient group (VDD，25-(OH)D3 ≤ 20 ng/mL), vitamin D insufficient group (VDI，25-(OH)D3 between>20 ng/mL and < 30 ng/mL), and vitamin D sufficient group (VDS，25-(OH)D3 ≥ 30 ng/mL). The correlation between the severity of lower extremity arterial plaques and serum 25-(OH)D3 levels was analyzed, as well as the risk factors for lower extremity arterial plaque formation in patients with T2DM.

RESULTS

The levels of 25-(OH)D3 in patients with arterial plaques were significantly lower than those in the NP (p = 0.002). Additionally, with the increasing severity of lower extremity arterial plaques, 25-(OH)D3 levels also decreased significantly (p = 0.01). The proportion of patients with sufficient 25-(OH)D3 levels was highest in NP, while the proportion of deficient and insufficient groups was higher in LP (p<0.001). Multivariate logistic regression analysis showed that low levels of 25-(OH)D3 were an independent risk factor for lower extremity arterial plaques in T2DM patients. Compared to patients with 25-(OH)D3>20 ng/mL, the odds ratios for the formation of moderate-risk plaques were 2.525 (95 % CI: 1.45-4.39) in patients with 25-(OH)D3 ≤ 20 ng/mL, and 2.893 (95 % CI: 1.59-5.26) for the formation of high-risk plaques.

CONCLUSION

Serum 25-(OH)D3 levels may be correlated with the occurrence and severity of lower extremity arterial plaques in patients with T2DM. Low serum 25-(OH)D3 concentration is a risk factor for lower extremity vascular lesions.

Pro-inflammatory markers are associated with response to sequential pharmacotherapy in major depressive disorder: a CAN-BIND-1 report

OBJECTIVE

There is limited literature on associations between inflammatory tone and response to sequential pharmacotherapies in major depressive disorder (MDD).

METHODS

In a 16-week open-label clinical trial, 211 participants with MDD were treated with escitalopram 10-20 mg daily for 8 weeks. Responders continued escitalopram while non-responders received adjunctive aripiprazole 2-10 mg daily for 8 weeks. Plasma levels of pro-inflammatory markers-C-reactive protein, interleukin (IL)-1β, IL-6, IL-17, interferon-gamma (IFN)-Γ, tumor necrosis factor (TNF)-α, and Chemokine C-C motif ligand-2 (CCL-2)-measured at baseline, and after 2, 8 and 16 weeks were included in logistic regression analyzes to assess associations between inflammatory markers and treatment response.

RESULTS

Pre-treatment IFN-Γ and CCL-2 levels were significantly associated with a lower of odds of response to escitalopram at 8 weeks. Increases in CCL-2 levels from weeks 8 to 16 in escitalopram non-responders were significantly associated with higher odds of non-response to adjunctive aripiprazole at week 16.

CONCLUSION

Higher pre-treatment levels of IFN-Γ and CCL-2 were associated with non-response to escitalopram. Increasing levels of these pro-inflammatory markers may be associated with non-response to adjunctive aripiprazole. These findings require validation in independent clinical populations.

Uncovering the Neural Correlates of Anhedonia Subtypes in Major Depressive Disorder: Implications for Intervention Strategies

Major depressive disorder (MDD) represents a serious public health concern, negatively affecting individuals' quality of life and making a substantial contribution to the global burden of disease. Anhedonia is a core symptom of MDD and is associated with poor treatment outcomes. Variability in anhedonia components within MDD has been observed, suggesting heterogeneity in psychopathology across subgroups. However, little is known about anhedonia subgroups in MDD and their underlying neural correlates across subgroups. To address this question, we employed a hierarchical cluster analysis based on Temporal Experience of Pleasure Scale subscales in 60 first-episode, drug-naive MDD patients and 32 healthy controls. Then we conducted a connectome-wide association study and whole-brain voxel-wise functional analyses for identified subgroups. There were three main findings: (1) three subgroups with different anhedonia profiles were identified using a data mining approach; (2) several parts of the reward network (especially pallidum and dorsal striatum) were associated with anticipatory and consummatory pleasure; (3) different patterns of within- and between-network connectivity contributed to the disparities of anhedonia profiles across three MDD subgroups. Here, we show that anhedonia in MDD is not uniform and can be categorized into distinct subgroups, and our research contributes to the understanding of neural underpinnings, offering potential treatment directions. This work emphasizes the need for tailored approaches in the complex landscape of MDD. The identification of homogeneous, stable, and neurobiologically valid MDD subtypes could significantly enhance our comprehension and management of this multifaceted condition.

Comorbidity between major depressive disorder and physical diseases: a comprehensive review of epidemiology, mechanisms and management

Populations with common physical diseases - such as cardiovascular diseases, cancer and neurodegenerative disorders - experience substantially higher rates of major depressive disorder (MDD) than the general population. On the other hand, people living with MDD have a greater risk for many physical diseases. This high level of comorbidity is associated with worse outcomes, reduced adherence to treatment, increased mortality, and greater health care utilization and costs. Comorbidity can also result in a range of clinical challenges, such as a more complicated therapeutic alliance, issues pertaining to adaptive health behaviors, drug-drug interactions and adverse events induced by medications used for physical and mental disorders. Potential explanations for the high prevalence of the above comorbidity involve shared genetic and biological pathways. These latter include inflammation, the gut microbiome, mitochondrial function and energy metabolism, hypothalamic-pituitary-adrenal axis dysregulation, and brain structure and function. Furthermore, MDD and physical diseases have in common several antecedents related to social factors (e.g., socioeconomic status), lifestyle variables (e.g., physical activity, diet, sleep), and stressful live events (e.g., childhood trauma). Pharmacotherapies and psychotherapies are effective treatments for comorbid MDD, and the introduction of lifestyle interventions as well as collaborative care models and digital technologies provide promising strategies for improving management. This paper aims to provide a detailed overview of the epidemiology of the comorbidity of MDD and specific physical diseases, including prevalence and bidirectional risk; of shared biological pathways potentially implicated in the pathogenesis of MDD and common physical diseases; of socio-environmental factors that serve as both shared risk and protective factors; and of management of MDD and physical diseases, including prevention and treatment. We conclude with future directions and emerging research related to optimal care of people with comorbid MDD and physical diseases.

Elevated serum leptin is associated with attenuated reward anticipation in major depressive disorder independent of peripheral C-reactive protein levels

Major depressive disorder (MDD) is associated with immunologic and metabolic alterations linked to central processing dysfunctions, including attenuated reward processing. This study investigated the associations between inflammation, metabolic hormones (leptin, insulin, adiponectin), and reward-related brain processing in MDD patients with high (MDD-High) and low (MDD-Low) C-reactive protein (CRP) levels compared to healthy comparison subjects (HC). Participants completed a blood draw and a monetary incentive delay task during functional magnetic resonance imaging. Although groups did not differ in insulin or adiponectin concentrations, both MDD-High (Wilcoxon p = 0.004, d = 0.65) and MDD-Low (Wilcoxon p = 0.046, d = 0.53) showed higher leptin concentrations than HC but did not differ from each other. Across MDD participants, higher leptin levels were associated with lower brain activation during reward anticipation in the left insula (r = - 0.30, p = 0.004) and left dorsolateral putamen (r = -- 0.24, p = 0.025). In contrast, within HC, higher leptin concentrations were associated with higher activation during reward anticipation in the same regions (insula: r = 0.40, p = 0.007; putamen: r = 0.37, p = 0.014). Depression may be characterized by elevated pro-inflammatory signaling via leptin concentrations through alternate inflammatory pathways distinct to CRP.

Microbiome and immuno-metabolic dysregulation in patients with major depressive disorder with atypical clinical presentation

Depression is highly prevalent (6% 1-year prevalence) and is the second leading cause of disability worldwide. Available treatment options for depression are far from optimal, with response rates only around 50%. This is most likely related to a heterogeneous clinical presentation of major depression disorder (MDD), suggesting different manifestations of underlying pathophysiological mechanisms. Poorer treatment outcomes to first-line antidepressants were reported in MDD patients endorsing an "atypical" symptom profile that is characterized by preserved reactivity in mood, increased appetite, hypersomnia, a heavy sensation in the limbs, and interpersonal rejection sensitivity. In recent years, evidence has emerged that immunometabolic biological dysregulation is an important underlying pathophysiological mechanism in depression, which maps more consistently to atypical features. In the last few years human microbial residents have emerged as a key influencing variable associated with immunometabolic dysregulations in depression. The microbiome plays a critical role in the training and development of key components of the host's innate and adaptive immune systems, while the immune system orchestrates the maintenance of key features of the host-microbe symbiosis. Moreover, by being a metabolically active ecosystem commensal microbes may have a huge impact on signaling pathways, involved in underlying mechanisms leading to atypical depressive symptoms. In this review, we discuss the interplay between the microbiome and immunometabolic imbalance in the context of atypical depressive symptoms. Although research in this field is in its infancy, targeting biological determinants in more homogeneous clinical presentations of MDD may offer new avenues for the development of novel therapeutic strategies for treatment-resistant depression.

Graves' disease as a driver of depression: a mechanistic insight

Graves' disease (GD) is characterized by diffuse enlargement and overactivity of the thyroid gland, which may be accompanied by other physical symptoms. Among them, depression can dramatically damage patients' quality of life, yet its prevalence in GD has not received adequate attention. Some studies have established a strong correlation between GD and increased risk of depression, though the data from current study remains limited. The summary of mechanistic insights regarding GD and depression has underpinned possible pathways by which GD contributes to depression. In this review, we first summarized the clinical evidence that supported the increased prevalence of depression by GD. We then concentrated on the mechanistic findings related to the acceleration of depression in the context of GD, as mounting evidence has indicated that GD promotes the development of depression through various mechanisms, including triggering autoimmune responses, inducing hormonal disorders, and influencing the thyroid-gut-microbiome-brain axis. Finally, we briefly presented potential therapeutic approaches to decreasing the risk of depression among patients with GD.

Differences in cognitive functions of atypical and non-atypical depression based on propensity score matching

BACKGROUND

Clinical and etiological heterogeneity have hindered our understanding of depression, thus driving the studies of major depressive disorder (MDD) subtypes. Atypical depression (AD) is a subtype of MDD with atypical features. Cognitive impairment is one of the factors that contribute to the suffering of patients with MDD. Therefore, this study investigated the characteristics and differences in cognitive functioning of AD and non-atypical depression (non-AD) using the MATRICS Consensus Cognitive Battery (MCCB).

METHODS

A total of 101 patients with AD and 252 patients with non-AD were assessed with the MCCB and clinical scales. Propensity score matching (PSM) was used to balance confounders between groups. After PSM, between-group differences were compared for cognitive and clinical variables. In addition, multiple linear regression analyses were performed to explore the effects of cognitive and clinical variables on the quality of life.

RESULTS

The AD group scored significantly lower in attention/vigilance and social cognition in all cognitive domains than the non-AD group. Attention/vigilance and social cognition were significant positive predictors of quality of life, whereas atypical symptoms and depressive severity were significant negative predictors.

CONCLUSIONS

This study suggests significant differences in cognitive functions between the AD and non-AD subtypes. Atypical symptoms and impaired cognition have a negative impact on patients' quality of life. Attention/vigilance and social cognition are worse in AD than non-AD, which the atypical features of patients with AD may explain. The pathological mechanisms and treatment strategies of AD should be further explored in the future to promote individualized treatment strategies.

Depression is a risk factor for metabolic syndrome: Results from the ELSA-Brasil cohort study

INTRODUCTION

Metabolic Syndrome (MetS) and depression comorbidity has been recognized, but its directionality is still uncertain. The aims of this study was to assess the association between depression (diagnosis and severity) and MetS (components, diagnosis and trajectory) in the baseline and over a 4-year follow-up period.

MATERIAL AND METHODS

Baseline and follow-up data from 13,883 participants of the Brazilian Longitudinal Study of Adult Health were analyzed. The Clinical Interview Schedule Revised assessed depressive episode and its severity. MetS components and diagnosis were assessed according to the National Cholesterol Education Program Adult Treatment Panel III. Participants were grouped according to MetS trajectory as recovered, incident and persistent MetS. Logistic regression analysis was conducted estimating odds ratios (OR) and 95% confidence intervals (95%CI).

RESULTS

Baseline depression was positively associated with recovered (OR = 1.59, 95%CI 1.18-2.14), incident (OR = 1.45, 95%CI 1.09-1.91) and persistent (OR = 1.70, 95%CI 1.39-2.07) MetS. Baseline depression was also associated with large waist circumference (OR = 1.47, 95%CI 1.23-1.75), high triglycerides (OR = 1.23, 95%CI 1.02-1.49), low high-density lipoprotein cholesterol (OR = 1.30, 95%CI 1.08-1.56), and hyperglycemia (OR = 1.38, 95%CI 1.15-1.66) at follow-up. Having three or more MetS components at follow-up was associated with baseline depression, with a positive dose-response effect (OR = 1.77, 95%CI 1.29-2.43; OR = 1.79, 95%CI 1.26-2.54; OR = 2.27, 95%CI 1.50-3.46, respectively). The magnitude of associations was greater in severe depression, when compared to moderate and mild.

DISCUSSION

These results support that depression is a risk factor for the development of MetS and highlights the need to follow metabolic and cardiovascular alterations in the presence of depression.

Emerging Materials, Wearables, and Diagnostic Advancements in Therapeutic Treatment of Brain Diseases

Among the most critical health issues, brain illnesses, such as neurodegenerative conditions and tumors, lower quality of life and have a significant economic impact. Implantable technology and nano-drug carriers have enormous promise for cerebral brain activity sensing and regulated therapeutic application in the treatment and detection of brain illnesses. Flexible materials are chosen for implantable devices because they help reduce biomechanical mismatch between the implanted device and brain tissue. Additionally, implanted biodegradable devices might lessen any autoimmune negative effects. The onerous subsequent operation for removing the implanted device is further lessened with biodegradability. This review expands on current developments in diagnostic technologies such as magnetic resonance imaging, computed tomography, mass spectroscopy, infrared spectroscopy, angiography, and electroencephalogram while providing an overview of prevalent brain diseases. As far as we are aware, there hasn't been a single review article that addresses all the prevalent brain illnesses. The reviewer also looks into the prospects for the future and offers suggestions for the direction of future developments in the treatment of brain diseases.

The genetics of bipolar disorder with obesity and type 2 diabetes

BACKGROUND

Bipolar disorder (BD) presents with high obesity and type 2 diabetes (T2D) and pathophysiological and phenomenological abnormalities shared with cardiometabolic disorders. Genomic studies may help define if they share genetic liability. This selective review of BD with obesity and T2D will focus on genomic studies, stress their current limitations and guide future steps in developing the field.

METHODS

We searched electronic databases (PubMed, Scopus) until December 2021 to identify genome-wide association studies, polygenic risk score analyses, and functional genomics of BD accounting for body mass index (BMI), obesity, or T2D.

RESULTS

The first genome-wide association studies (GWAS) of BD accounting for obesity found a promising genome-wide association in an intronic gene variant of TCF7L2 that was further replicated. Polygenic risk scores of obesity and T2D have also been associated with BD, yet, no genetic correlations have been demonstrated. Finally, human-induced stem cell studies of the intronic variant in TCF7L2 show a potential biological impact of the products of this genetic variant in BD risk.

LIMITATIONS

The narrative nature of this review.

CONCLUSIONS

Findings from BD GWAS accounting for obesity and their functional testing, have prompted potential biological insights. Yet, BD, obesity, and T2D display high phenotypic, genetic, and population-related heterogeneity, limiting our ability to detect genetic associations. Further studies should refine cardiometabolic phenotypes, test gene-environmental interactions and add population diversity.

Insulin resistance as a marker for the immune-metabolic subtype of depression

OBJECTIVE

Insulin resistance (IR), a marker of metabolic dysregulation and pro-inflammatory state, moderates the antidepressant treatment effect in patients with type 2 diabetes (T2D) and is therefore a potential marker for personalized treatment. Based on data from a light therapy trial (NTR4942), we aimed to evaluate whether 1) depression symptoms differ according to the level of IR, and 2) improvement of specific depression symptoms drive the positive effects of light therapy in those with higher IR.

METHODS

This secondary analysis in 59 individuals with depression and T2D explored differences in depressive symptom profile (30-item Inventory of Depressive Symptomatology (IDS)) at baseline and in response to light therapy (versus placebo), between lower and higher IR individuals, using Likelihood Ratio tests and Linear-by-linear association. IR was measured using the gold standard, a hyperinsulinemic-euglycaemic clamp.

RESULTS

At baseline, higher IR individuals reported more symptoms of irritability (p=0.024) anhedonia (no interest in people and activities: p=0.011; absence of pleasure and enjoyment: p=0.021), fatigue (fatigue: p=0.036; physical fatigue: p=0.035) and hypersomnia (p=0.029) relative to persons with lower IR, who reported more insomnia (nightly awakening: p=0.041; early morning awakening: p=0.012). Light therapy led to an improvement across IDS symptoms in higher IR individuals, while in lower IR individuals, light therapy improved early morning awakening (p=0.005) and interest in people and activities (p=0.015), but worsened mood (feeling sad: p=0.001; feeling irritable: p=0.002; interpersonal sensitivity: p=0.014).

CONCLUSIONS

Results add to the hypothesis of an immune-metabolic subtype of depression, and suggest that IR might be a promising focus for precision medicine.

Circulating Inflammation Markers Partly Explain the Link Between the Dietary Inflammatory Index and Depressive Symptoms

BACKGROUND

Depression is a mood disorder characterized by a high rate of resistance to pharmacological treatments, which has often been linked to chronic inflammation. This can be influenced by different environmental factors, in particular pro-inflammatory diets. However, a mediating role of circulating inflammation has never been observed.

AIM

To test the association between a dietary inflammatory index (DII®) and continuous depressive symptoms (adapted version of PHQ9) in an Italian population cohort (N=13,301), along with potential explanatory effect of a composite index (INFLA-score) based on four circulating inflammatory biomarkers: C-reactive protein, granulocyte-to-lymphocyte ratio, platelet and white blood cell counts.

RESULTS

Significant positive associations were observed between DII and total depressive symptoms (standardized β (SE) = 0.038 (0.005), p < 0.001), and with two factors tagging somatic (0.012 (0.003), p < 0.001) and cognitive symptoms (0.012 (0.003), p < 0.001), after adjustment for different potential confounders (socioeconomic status, chronic health conditions and lifestyles). These associations were about twice as strong in women than in men. INFLA-score explained a small but significant proportion of the association with total depressive symptoms (0.90-2.30%, p < 0.05), which was mainly driven by granulocyte-to-lymphocyte ratio (1.18-1.65%). This effect was even stronger for the somatic (2.66-4.66%) but not for the cognitive factor (0%).

CONCLUSION

These findings support a strong link between inflammatory diet and depression, especially with somatic symptoms and within women. Moreover, they provide novel evidence for a potential explanatory role of circulating inflammation in this association, suggesting new paths for prevention and treatment of major and atypical depression.

Mechanism exploration of Gouqi-wentang formula against type 2 diabetes mellitus by phytochemistry and network pharmacology-based analysis and biological validation

BACKGROUND

The Gouqi-wentang formula (GQWTF) is a herbal formula used by Academician Xiao-lin Tong for the clinical treatment of T2DM. GQWTF is beneficial to qi, nourishes Yin, clears heat, and promotes fluid production, but the effective components and their mechanism of action remain unclear.

METHODS

The main components of GQWTF were detected by LC-MS, and the multi-target mechanisms of GQWTF in T2DM were elucidated using network pharmacology analysis, including target prediction, protein-protein interaction network construction and analysis, Gene Ontology (GO) terms, Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway annotation, and other network construction. Finally, the efficacy of the GQWTF was verified using biological experiments.

RESULTS

First, the "herb-channel tropism" network suggested that GQWTF focuses more on treating diseases by recuperating the liver, which is considered as an important insulin-sensitive organ. Subsequently, a total of 16 active ingredients in GQWTF were detected and screened, and their biological targets were predicted. Then, "compound-target" network was constructed, where enrichment analysis of GQWTF targets reflected its potential pharmacological activities. After T2DM-related target identification, 39 cross targets of GQWTF and T2DM were obtained, and 30 key targets highly responsible for the beneficial effect of GQWTF on T2DM were identified by PPI analysis. GO analysis of these key targets showed that many biological processes of GQWTF in treating T2DM are key in the occurrence and development of T2DM, including components related to inflammatory/immune response, insulin, and metabolism. KEGG analysis revealed the regulation of multiple signalling pathways, such as insulin resistance, PPAR signalling pathway, FoxO signalling pathway, Fc epsilon RI signalling pathway, and pathways that influence diabetes primarily by regulating metabolism as well as other T2DM directly related pathways. Furthermore, a "formula-compound-pathway-symptom" network was constructed to represent a global view of GQWTF in the treatment of T2DM.

CONCLUSIONS

This study explored the mechanism of action of GQWTF in T2DM by multi-component and multi-target multi pathways, which could provide a theoretical basis for the development and clinical application of GQWTF.

Update on the Relationship Between Depression and Neuroendocrine Metabolism

Through the past decade of research, the correlation between depression and metabolic diseases has been noticed. More and more studies have confirmed that depression is comorbid with a variety of metabolic diseases, such as obesity, diabetes, metabolic syndrome and so on. Studies showed that the underlying mechanisms of both depression and metabolic diseases include chronic inflammatory state, which is significantly related to the severity. In addition, they also involve endocrine, immune systems. At present, the effects of clinical treatments of depression is limited. Therefore, exploring the co-disease mechanism of depression and metabolic diseases is helpful to find a new clinical therapeutic intervention strategy. Herein, focusing on the relationship between depression and metabolic diseases, this manuscript aims to provide an overview of the comorbidity of depression and metabolic.

Chlorogenic Acid-Induced Gut Microbiota Improves Metabolic Endotoxemia

BACKGROUND

Coffee can regulate glucose homeostasis but the underlying mechanism is unclear. This study investigated the preventive and therapeutic effects of chlorogenic acid (CGA), a polyphenol that is found in coffee, on obesity and obesity-related metabolic endotoxemia.

METHOD

Male 4-week-old C57BL/6 mice were fed either normal chow or a high-fat diet or 20 weeks and half the mice in each group were gavaged with CGA. Oral glucose tolerance tests (OGTTs) and insulin tolerance tests (ITTs) were performed. Markers of inflammation and intestinal barrier function were assayed. The composition of the gut microbiota was analyzed by 16S rRNA high-throughput pyrosequencing. The role of CGA-altered microbiota in metabolic endotoxemia was verified by fecal microbiota transplantation.

RESULTS

CGA protected against HFD-induced weight gain, decreased the relative weight of subcutaneous and visceral adipose, improved intestinal barrier integrity, and prevented glucose metabolic disorders and endotoxemia (P <0.05). CGA significantly changed the composition of the gut microbiota and increased the abundance of short chain fatty acid (SCFA)-producers (e.g., Dubosiella, Romboutsia, Mucispirillum, and Faecalibaculum) and Akkermansia, which can protect the intestinal barrier. In addition, mice with the CGA-altered microbiota had decreased body weight and fat content and inhibited metabolic endotoxemia.

CONCLUSION

CGA-induced changes in the gut microbiota played an important role in the inhibition of metabolic endotoxemia in HFD-fed mice.