Leptin and adiponectin levels in major depressive disorder: A systematic review and meta-analysis

Recurrent depression predicts high leptin concentrations in patients with coronary artery disease over an 18-months follow-up period: Findings from the prospective multicenter randomized controlled SPIRR-CAD Trial

BACKGROUND

Leptin, an adipokine suspected to play a role in coronary artery disease (CAD), may also be associated with deteriorated mental health. We investigated the prospective impact of recurrent depressed mood (RDM) on heightened plasma leptin levels in CAD patients.

METHODS

Derived from the randomized SPIRR-CAD trial, plasma leptin were measured by the Human Leptin DuoSet ELISA at baseline in 539 patients (including 115 (21.3 %) women and 424 (78.7 %) men) and in 373 participants after 18-months follow up (T3). RDM was based on the clinical course from baseline to follow-up assessed by the Hamilton Depression Rating Scale (HAMD). Multivariate binary logistic regression models identified predictors for heightened leptin at T3.

RESULTS

At baseline, highest leptin level (3rd tertile) was associated with type 2 diabetes (p = 0.009), heart failure symptoms (NYHA III) (p < 0.001), female sex and BMI ≥30 (p < 0.001) but not with age and depression. At study endpoint (T3), RDM was associated with a substantially increased risk of experiencing the highest plasma leptin level (OR 2.92 (95 % CI 1.27-6.75)) followed by increased NT-proBNP (the most prominent indicator of CHF) with an OR of 2.73 (1.22-6.11) - both after adjustment for concurrent factors including weight gain (diff BMI T3-T1) over the study period - the latter accounting for an OR of 1.41 (1.17-1.70).

LIMITATIONS

Findings are limited to people of Caucasian ancestry which prevents being generalized to other ethnicities. Although relying upon a prospective design, reverse causality cannot be excluded but is unlikely.

CONCLUSIONS

In CAD patients, RDM is a significant predictor of heightened leptin -a finding opening room for a new pathway of the psychobiological underpinning of depression on CAD risk.

Leptin and leptin receptor gene polymorphisms and depression treatment response

OBJECTIVE

Associations between leptin (LEP) and leptin receptor (LEPR) gene polymorphisms and mood disorders have been found but not yet confirmed in multiple studies. The aim of our study was to study the associations between LEP and LEPR single nucleotide polymorphisms (SNPs) and treatment response of depression. Associations between leptin levels and depression severity were also investigated.

METHODS

The data included 242 depressed patients in secondary psychiatric care. Symptoms of depression were assessed with the Montgomery–Åsberg Depression Rating Scale (MADRS). Previously found LEP and LEPR SNPs associated with depression and other mood disorders were studied. Furthermore, all available LEP and LEPR SNPs were clumped using proxy SNPs to represent gene areas in r2 > 0.2 linkage disequilibrium and their association with treatment response was analysed with logistic regression.

RESULTS

Two proxy SNPs of LEPR gene, rs12564738 and rs12029311, were associated with MADRS response at 6 weeks (p adjusted = 0.024, p adjusted = 0.024). SNPs from previous studies were not associated with MADRS response, but LEPR rs12145690 from a previous study was strongly associated with rs12564738 (r2 = 0.94). The positive association between leptin levels and MADRS score at baseline after adjusting with age, sex, body mass index (BMI), Alcohol Use Disorders Identification Test score, and smoking was found (p = 0.011).

CONCLUSION

Our findings suggest that LEPR polymorphisms are associated with depression treatment response. We also found associations between leptin levels and depression independently of BMI. Further studies and meta-analyses are needed to confirm the significance of found SNPs and the role of leptin in depression.

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.

Adiponectin and Inflammatory Marker Levels in the Elderly Patients with Diabetes, Mild Cognitive Impairment and Depressive Symptoms

Some studies suggest that low-grade inflammation and adipokines may be involved in mild cognitive impairment (MCI) and depression in subjects with type 2 diabetes; however, the available data concerning the elderly population are limited. Therefore, we conducted novel research to determine the serum adiponectin, hs-CRP and TNF-α levels in elderly diabetic patients with MCI and depressive symptoms and to identify the factors associated with MCI in this group. A total of 178 diabetic patients (mean age 84.4 ± 3.4 years) were screened for MCI and depressive symptoms. Various biochemical and biomarker data were collected. We found that patients with MCI and depressive symptoms demonstrated lower adiponectin levels and high hs-CRP and TNF-α. In this group, adiponectin concentration was negatively correlated with hs-CRP, TNF-α, HbA1c, and GDS-30 scores and positively correlated with MoCA scores. Multivariable analysis found the risk of MCI to be associated with higher TNF-α levels, fewer years of formal education, an increased number of comorbidities, and the presence of CVD. We concluded that low-grade inflammation and the presence of adipokines are associated with MCI and depressive symptoms in elderly diabetics. Further research should evaluate the suitability of Hs-CRP, TNF-α, and adiponectin as diagnostic markers for MCI and potential therapeutic targets.

Adipokines measured during pregnancy and at birth are associated with infant negative affect

BACKGROUND

Increased adiposity during pregnancy may be related to offspring risk for mental health disorders, although the biological mechanisms are poorly understood. One promising hypothesis is that factors secreted from adipocytes such as leptin and adiponectin may explain this association. The current study examined whether pregnancy or umbilical cord blood concentrations of leptin and/or adiponectin a) predict elevated infant negative affect at 6 months (an early life marker of risk for psychopathology); and b) help explain the association between pregnancy adiposity and increased infant negative affect.

METHODS

Data came from a prospective cohort (N = 305) of pregnant individuals and their offspring. Second trimester adiposity was assessed using air displacement plethysmography. Concentrations of leptin and adiponectin were measured in second trimester plasma and umbilical cord plasma. Infant negative affect was assessed by standardized observation at 6 months. Second trimester inflammation was assessed using a comprehensive panel of cytokines.

RESULTS

Lower second trimester adiponectin was associated with elevated infant negative affect, and mediated the effect of pregnancy adiposity on infant negative affect. This association was independent of the effect of second trimester inflammation. Umbilical cord leptin also predicted higher infant negative affect and mediated the association between pregnancy adiposity and infant negative affect.

CONCLUSIONS

This is the first study to link pregnancy adiponectin or cord blood leptin to infant markers of risk for psychopathology, and the first to demonstrate that these adipokines mediate the association between pregnancy adiposity and offspring behavioral outcomes, suggesting novel markers of risk and potential mechanisms of effect.

Ghrelin is associated with an elevated mood after an overnight fast in depression

BACKGROUND

Major depressive disorder (MDD) comprises subtypes with distinct symptom profiles. For example, patients with melancholic and atypical MDD differ in the direction of appetite and body weight changes as well as mood reactivity. Despite reported links to altered energy metabolism, the role of circulating neuropeptides from the gut in modulating such symptoms remains largely elusive.

METHODS

We collected data from 103 participants, including 52 patients with MDD and 51 healthy control participants (HCP). After an overnight fast, we measured plasma levels of (acyl and des-acyl) ghrelin and participants reported their current metabolic and mood states using visual analog scales (VAS). Furthermore, they completed symptom-related questionnaires (i.e., STAI-T).

RESULTS

Patients with atypical versus melancholic MDD reported less negative affect (p = 0.025). Higher levels of acyl ghrelin (corrected for BMI) were associated with improved mood (p = 0.012), specifically in patients with MDD. These associations of ghrelin were not mood-item specific and exceeded correlations with trait markers of negative affectivity. In contrast to associations with mood state, higher levels of ghrelin were not associated with increased hunger per se or changes in appetite in patients with MDD.

LIMITATIONS

The study is limited by the cross-sectional design without an intervention.

CONCLUSIONS

Our results reveal potentially mood-enhancing effects of ghrelin in fasting individuals that exceed associations with metabolic state ratings. These associations with circulating neuropeptides might help explain anti-depressive effects of fasting interventions and could complement conventional treatments in patients with melancholic MDD.

Leptin's Inverse Association With Brain Morphology and Depressive Symptoms: A Discovery and Confirmatory Study Across 2 Independent Samples

BACKGROUND

Major depressive disorder has a complex, bidirectional relationship with metabolic dysfunction, but the neural correlates of this association are not well understood.

METHODS

In this cross-sectional investigation, we used a 2-step discovery and confirmatory strategy utilizing 2 independent samples (sample 1: 288 participants, sample 2: 196 participants) to examine the association between circulating indicators of metabolic health (leptin and adiponectin) and brain structures in individuals with major depressive disorder.

RESULTS

We found a replicable inverse correlation between leptin levels and cortical surface area within essential brain areas responsible for emotion regulation, such as the left posterior cingulate cortex, right pars orbitalis, right superior temporal gyrus, and right insula (standardized beta coefficient range: -0.27 to -0.49, puncorrected < .05). Notably, this relationship was independent of C-reactive protein levels. We also identified a significant interaction effect of leptin levels and diagnosis on the cortical surface area of the right superior temporal gyrus (standardized beta coefficient = 0.26 in sample 1, standardized beta coefficient = 0.30 in sample 2, puncorrected < .05). We also observed a positive correlation between leptin levels and atypical depressive symptoms in both major depressive disorder groups (r = 0.14 in sample 1, r = 0.29 in sample 2, puncorrected < .05).

CONCLUSIONS

The inverse association between leptin and cortical surface area in brain regions that are important for emotion processing and leptin's association with atypical depressive symptoms support the hypothesis that metabolic processes may be related to emotion regulation. However, the molecular mechanisms through which leptin may exert these effects should be explored further.

Association between endocrine and neuropsychological endophenotypes and gambling disorder severity

BACKGROUND

Neurobiological characteristics have been identified regarding the severity of gambling disorder (GD). The aims of this study were: (1) to examine, through a path analysis, whether there was a relationship between neuroendocrine features, potentially mediational GD variables, and GD severity, and (2) to associate neuroendocrine variables, with GD severity-related variables according to gambling preferences.

METHODS

The sample included 297 outpatients with GD. We analyzed endocrine concentrations of different appetite-related hormones (ghrelin, liver antimicrobial peptide 2 [LEAP-2], leptin, adiponectin), and neuropsychological performance (working memory, cognitive flexibility, inhibition, decision making, premorbid intelligence). Path analysis assessed mechanisms between neuroendocrine features and GD severity, including mediational GD variables (impulsivity traits and gambling-related cognitive distortions). Partial correlations evaluated the associations between neuroendocrine variables, including impulsivity traits, and variables related to GD severity (DSM-5, South Oaks Gambling Screen, illness duration, and gambling-related cognitive distortions).

RESULTS

Lower adiponectin concentrations predicted greater GD severity, while higher LEAP-2 concentrations predicted more gambling-related cognitive distortions. Likewise, better neuropsychological performance directly predicted GD severity, but worse neuropsychological performance was associated with GD severity through the mediational variables of impulsivity traits and gambling-related cognitive distortions. Also, in non-strategic individuals with GD, poor working memory was associated with gambling expectancies and predictive control. In strategic individuals with GD, poor cognitive flexibility was associated with illusion of control, predictive control, and inability to stop gambling.

CONCLUSIONS

These results provide updated information about the comprehension of the interaction between neuroendocrine features, clinical variables, and severity of GD. Thus, neurobiological functions seem to be strongly related to GD severity.

Adipokines in depressed women with and without adverse childhood experiences

BACKGROUND

Adverse childhood experiences (ACE) elevate the risk of both major depressive disorder (MDD) and metabolic diseases. The underlying pathophysiology might include alterations of adipokine levels as a consequence of ACE. In this study, we used a full-factorial design to investigate the levels of select adipokines in women with ACE-only (n = 23), MDD-only (n = 27), ACE+MDD (n = 25) and healthy controls (HC, n = 29) to identify metabolic makers associated with vulnerability and resilience of developing MDD after ACE exposure.

METHODS

Serum levels of adiponectin, leptin, adiponectin-to-leptin (A/L) ratio, and retinol binding protein 4 (RBP4) were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Adiponectin levels did not differ between groups. Individuals with vs. without MDD showed higher leptin serum concentrations. As predicted, A/L ratio indicated lower values in individuals with vs. without ACE. RBP4 showed a more nuanced pattern with reduced levels in the ACE-only and MDD-only groups compared to HC. Furthermore, the ACE-only group showed lower RBP4 concentrations compared to ACE+MDD. These results were not accounted by BMI or medication status.

CONCLUSION

Our results do not support the utility of adiponectin and leptin as predictors of vulnerability or resilience of developing MDD after ACE. In contrast, RBP4 might play a role in resilience towards the development of MDD following ACE. Further research on this more recently discovered adipokine seems warranted.

Neurological and metabolic related pathophysiologies and treatment of comorbid diabetes with depression

BACKGROUND

The comorbidity between diabetes mellitus and depression was revealed, and diabetes mellitus increased the prevalence of depressive disorder, which ranked 13th in the leading causes of disability-adjusted life-years. Insulin resistance, which is common in diabetes mellitus, has increased the risk of depressive symptoms in both humans and animals. However, the mechanisms behind the comorbidity are multi-factorial and complicated. There is still no causal chain to explain the comorbidity exactly. Moreover, Selective serotonin reuptake inhibitors, insulin and metformin, which are recommended for treating diabetes mellitus-induced depression, were found to be a risk factor in some complications of diabetes.

AIMS

Given these problems, many researchers made remarkable efforts to analyze diabetes complicating depression from different aspects, including insulin resistance, stress and Hypothalamic-Pituitary-Adrenal axis, neurological system, oxidative stress, and inflammation. Drug therapy, such as Hydrogen Sulfide, Cannabidiol, Ascorbic Acid and Hesperidin, are conducive to alleviating diabetes mellitus and depression. Here, we reviewed the exact pathophysiology underlying the comorbidity between depressive disorder and diabetes mellitus and drug therapy.

METHODS

The review refers to the available literature in PubMed and Web of Science, searching critical terms related to diabetes mellitus, depression and drug therapy.

RESULTS

In this review, we found that brain structure and function, neurogenesis, brain-derived neurotrophic factor and glucose and lipid metabolism were involved in the pathophysiology of the comorbidity. Obesity might lead to diabetes mellitus and depression through reduced adiponectin and increased leptin and resistin. In addition, drug therapy displayed in this review could expand the region of potential therapy.

CONCLUSIONS

The review summarizes the mechanisms underlying the comorbidity. It also overviews drug therapy with anti-diabetic and anti-depressant effects.

A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network

Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.

A cross talk on the role of contemporary biomarkers in depression

Introduction: Biomarkers can be used to identify determinants of response to various treatments of mental disorders. Evidence to date demonstrates that markers of inflammatory, neurotransmitter, neurotrophic, neuroendocrine, and metabolic function can predict the psychological and physical consequences of depression in individuals, allowing for the development of new therapeutic targets with fewer side effects. Extensive research has included hundreds of potential biomarkers of depression, but their roles in depression, abnormal patients, and how bioinformatics can be used to improve diagnosis, treatment, and prognosis have not been determined or defined. To determine which biomarkers can and cannot be used to predict treatment response, classify patients for specific treatments, and develop targets for new interventions, proprietary strategies, and current research projects need to be tailored.Material and Methods: This review article focuses on - biomarker systems that would help in the further development and expansion of newer targets - which holds great promise for reducing the burden of depression.Results and Discussion: Further, this review point to the inflammatory response, metabolic marker, and microribonucleic acids, long non-coding RNAs, HPA axis which are - related to depression and can serve as future targets.

Cluster analysis in gambling disorder based on sociodemographic, neuropsychological, and neuroendocrine features regulating energy homeostasis

BACKGROUND

The heterogeneity of gambling disorder (GD) has led to the identification of different subtypes, mostly including phenotypic features, with distinctive implications on the GD severity and treatment outcome. However, clustering analyses based on potential endophenotypic features, such as neuropsychological and neuroendocrine factors, are scarce so far.

AIMS

This study firstly aimed to identify empirical clusters in individuals with GD based on sociodemographic (i.e., age and sex), neuropsychological (i.e., cognitive flexibility, inhibitory control, decision making, working memory, attention, and set-shifting), and neuroendocrine factors regulating energy homeostasis (i.e., leptin, ghrelin, adiponectin, and liver-expressed antimicrobial peptide 2, LEAP-2). The second objective was to compare the profiles between clusters, considering the variables used for the clustering procedure and other different sociodemographic, clinical, and psychological features.

METHODS

297 seeking-treatment adult outpatients with GD (93.6% males, mean age of 39.58 years old) were evaluated through a semi-structured clinical interview, self-reported psychometric assessments, and a protocolized neuropsychological battery. Plasma concentrations of neuroendocrine factors were assessed in peripheral blood after an overnight fast. Agglomerative hierarchical clustering was applied using sociodemographic, neuropsychological, and neuroendocrine variables as indicators for the grouping procedure. Comparisons between the empirical groups were performed using Chi-square tests (χ2) for categorical variables, and analysis of variance (ANOVA) for quantitative measures.

RESULTS

Three-mutually-exclusive groups were obtained, being neuropsychological features those with the greatest weight in differentiating groups. The largest cluster (Cluster 1, 65.3%) was composed by younger males with strategic and online gambling preferences, scoring higher on self-reported impulsivity traits, but with a lower cognitive impairment. Cluster 2 (18.2%) and 3 (16.5%) were characterized by a significantly higher proportion of females and older patients with non-strategic gambling preferences and a worse neuropsychological performance. Particularly, Cluster 3 had the poorest neuropsychological performance, especially in cognitive flexibility, while Cluster 2 reported the poorest inhibitory control. This latter cluster was also distinguished by a poorer self-reported emotion regulation, the highest prevalence of food addiction, as well as a metabolic profile characterized by the highest mean concentrations of leptin, adiponectin, and LEAP-2.

CONCLUSIONS

To the best of our knowledge, this is the first study to identify well-differentiated GD clusters using neuropsychological and neuroendocrine features. Our findings reinforce the heterogeneous nature of the disorder and emphasize a role of potential endophenotypic features in GD subtyping. This more comprehensive characterization of GD profiles could contribute to optimize therapeutic interventions based on a medicine of precision.

Impaired eating behaviors but intact metabolic hormone levels in individuals with major depressive disorder and generalized anxiety disorder

BACKGROUND

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) contribute significantly to global health burdens. Identifying disease markers for these comorbid disorders can increase understanding of pathogenesis and improve screening and intervention strategies. This study examined the association of physical health factors with MDD and MDD + GAD, across sexes.

METHODS

Two samples of participants from the Tulsa-1000 study (exploratory cohort: N = 136; confirmatory cohort: N = 185) completed body composition measurements, eating behavior (Three Factor Eating Questionnaire [TFEQ], Eating Disorder Diagnostic Scale [EDDS]), exercise questionnaires, and a blood draw. Metabolic hormone concentrations (leptin, insulin, and adiponectin) were analyzed from blood samples. Within each cohort, a two-way analysis of variance compared three groups (MDD, MDD + GAD, and healthy controls [HC]), sex, and their interaction on dependent variables. Hedges g was calculated to reflect effect size magnitude.

RESULTS

Medium-to-large group main effects across cohorts indicated that compared to HC: (1) MDD (g = 1.71/0.57) and MDD + GAD (g = 0.93/0.69) reported higher TFEQ Disinhibition scores; (2) MDD endorsed higher TFEQ Hunger scores (g = 0.66/0.48); and (3) MDD (g = 1.60/1.30) and MDD + GAD (g = 0.92/1.72) reported greater EDDS scores. Large sex main effects across cohorts indicated that females exhibited higher levels than males for percent body fat (g = 1.07/1.17), leptin (g = 1.27/1.12), and adiponectin (g=0.82/0.88).

LIMITATIONS

The power to detect group*sex interactions was limited due to a greater number of females (than males) in the study, and over half of clinical participants were taking medications.

CONCLUSIONS

Individuals with MDD and MDD + GAD demonstrate difficulties in regulating eating behaviors, potentially contributing to functional impairment and increased disease burden.

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.

Personalized Medicine of Omega-3 Fatty Acids in Depression Treatment in Obese and Metabolically Dysregulated Patients

The co-occurrence of depression and obesity has become a significant public health concern worldwide. Recent studies have shown that metabolic dysfunction, which is commonly observed in obese individuals and is characterized by inflammation, insulin resistance, leptin resistance, and hypertension, is a critical risk factor for depression. This dysfunction may induce structural and functional changes in the brain, ultimately contributing to depression's development. Given that obesity and depression mutually increase each other's risk of development by 50-60%, there is a need for effective interventions that address both conditions. The comorbidity of depression with obesity and metabolic dysregulation is thought to be related to chronic low-grade inflammation, characterized by increased circulating levels of pro-inflammatory cytokines and C-reactive protein (CRP). As pharmacotherapy fails in at least 30-40% of cases to adequately treat major depressive disorder, a nutritional approach is emerging as a promising alternative. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are a promising dietary intervention that can reduce inflammatory biomarkers, particularly in patients with high levels of inflammation, including pregnant women with gestational diabetes, patients with type 2 diabetes mellitus, and overweight individuals with major depressive disorder. Further efforts directed at implementing these strategies in clinical practice could contribute to improved outcomes in patients with depression, comorbid obesity, and/or metabolic dysregulation.

The Relationship between Insomnia and the Pathophysiology of Major Depressive Disorder: An Evaluation of a Broad Selection of Serum and Urine Biomarkers

Insomnia exhibits a clinically relevant relationship with major depressive disorder (MDD). Increasing evidence suggests that insomnia is associated with neurobiological alterations that resemble the pathophysiology of MDD. However, research in a clinical population is limited. The present study, therefore, aimed to investigate the relationship between insomnia and the main pathophysiological mechanisms of MDD in a clinical sample of individuals with MDD. Data were extracted from three cohorts (N = 227) and included an evaluation of depression severity (Quick Inventory of Depressive Symptomatology, QIDS-SR₁₆) and insomnia severity (QIDS-SR₁₆ insomnia items) as well as serum and urine assessments of 24 immunologic (e.g., tumour necrosis factor α receptor 2 and calprotectin), neurotrophic (e.g., brain-derived neurotrophic factor and epidermal growth factor), neuroendocrine (e.g., cortisol and aldosterone), neuropeptide (i.e., substance P), and metabolic (e.g., leptin and acetyl-L-carnitine) biomarkers. Linear regression analyses evaluating the association between insomnia severity and biomarker levels were conducted with and without controlling for depression severity (M = 17.32), antidepressant use (18.9%), gender (59.0% female; 40.5% male), age (M = 42.04), and the cohort of origin. The results demonstrated no significant associations between insomnia severity and biomarker levels. In conclusion, for the included biomarkers, current findings reveal no contribution of insomnia to the clinical pathophysiology of MDD.

Adipocytokine correlates of childhood and adolescent mental health: A systematic review

The objective of this systematic review was to determine the current state of the literature regarding how adipocytokines associate with mental health symptoms/disorders in youth. Findings summarized in this review suggested that in neurodevelopmental disorders, higher levels of leptin, ghrelin, resistin, and visfatin as well as lower levels of adiponectin, retinol-binding protein 4, and progranulin predicted increased risk for or were conflated with autism spectrum disorder. Adipocytokine correlates of attention-deficit hyperactivity disorder and related symptoms included higher apelin, higher leptin-to-adiponectin ratio, and lower adiponectin. Evidence from studies examining anxiety symptoms evinced mixed results regarding leptin, and one study suggested higher levels of ghrelin. Depressive symptoms correlated with higher leptin and ghrelin. Research examining posttraumatic stress symptoms found higher levels of ghrelin. In research examining broadband symptoms, conflicting results emerged for associations between internalizing symptoms (i.e., symptoms of emotional stress) and leptin in youth. Low levels of adiponectin and high levels of leptin predicted externalizing symptoms. Total symptom difficulties were associated with a higher leptin-to-adiponectin ratio. Our findings suggest that adipocytokines may be an important set of biomarkers to consider as underlying mechanisms contributing to developmental psychopathology.

Correlation between improved leptin signaling and cognitive function post bariatric surgery

Determining whether changes in leptin signaling plays a role in the improvement of cognitive function post-bariatric surgery may aid in the understanding and development of novel therapeutic approaches targeting cognitive dysfunction through the greater understanding of processes connecting obesity and brain health. Several studies have explored the effects of cognition post bariatric surgery, and others have studied leptin and its changes post surgery. However the amalgamation of the effects of leptin signaling in relation to cognition post bariatric surgery have yet to be considered as key tools in the understanding of cognitive dysfunction in obese subjects with leptin resistance or insensitivity. This review serves to highlight the potential correlations, to further elucidate the effect of improved leptin signaling on cognition post bariatric surgery, and to propose a direct cause for the improvement of cognitive function via the amelioration of the leptin Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling pathway as a result of the reversal of inflammatory processes involved in diseased individuals.

Glucocorticoids, stress and eating: The mediating role of appetite-regulating hormones

Disrupted hormonal appetite signaling plays a crucial role in obesity as it may lead to uncontrolled reward-related eating. Such disturbances can be induced not only by weight gain itself but also by glucocorticoid overexposure, for example, due to chronic stress, disease, or medication use. However, the exact pathways are just starting to be understood. Here, we present a conceptual framework of how glucocorticoid excess may impair hormonal appetite signaling and, consequently, eating control in the context of obesity. The evidence we present suggests that counteracting glucocorticoid excess can lead to improvements in appetite signaling and may therefore pose a crucial target for obesity prevention and treatment. In turn, targeting hormonal appetite signals may not only improve weight management and eating behavior but may also decrease detrimental effects of glucocorticoid excess on cardio-metabolic outcomes and mood. We conclude that gaining a better understanding of the relationship between glucocorticoid excess and circulating appetite signals will contribute greatly to improvements in personalized obesity prevention and treatment.

Adiponectin, leptin, cortisol, neuropeptide Y and profile of mood states in athletes participating in an ultramarathon during winter: An observational study

Background: The Montane^® Yukon Arctic Ultra (YAU) is one of the longest (690 km) and coldest (+10.6°C-43.9°C) ultramarathons worldwide. Taking part in an ultramarathon is associated with great physiological and psychological stress, which can affect one's mood, level of hormones, and peptides. The current study aimed to identify relationships between peptides, hormones, and mood states in participants during this ultramarathon. Methods: The study cohort consisted of 36 participants (19 men, 17 women, 38.64 ± 9.12 years) split into a finisher (n = 10), non-finisher (n = 19), and control group (n = 7). Data were collected at four time points: baseline (PRE), during (D1 after 277 km, D2 after 383 km), and after the race (POST). Questionnaires were used to assess ratings of perceived exertion (RPE), total quality of recovery (TQR), and profile of mood states (POMS-SF). Serum NPY, leptin, adiponectin, and cortisol were measured. Results: Among non-finishers, scores for confusion, anger, depression, and tension-anxiety (PRE vs. D2, p < 0.05) increased, while vigor decreased (PRE vs. D1, p < 0.05). In contrast, finishers' tension-anxiety scores decreased (PRE vs. D1, p < 0.05). Fatigue increased in finishers (PRE vs. POST, p < 0.05) and non-finishers (PRE vs. D1, p < 0.05). In non-finishers, depressive mood correlated positively with leptin, anger, and confusion at several time points (p < 0.001). In finishers, NPY correlated with TQR at PRE (p < 0.05), while leptin correlated negatively with TQR at POST (p < 0.05). Tension-anxiety correlated highly with perceived exertion in non-finishers (p < 0.001) and with cortisol in finishers (p < 0.05) and non-finishers (p < 0.001). In finishers, confusion correlated negatively with NPY (p < 0.01). Conclusion: The study reveals an essential interplay between hormones and mood states affecting performance: Leptin was associated with anger and a depressive mood state in non-finishers and worse recovery in finishers. In contrast, NPY appeared linked to a lower confusion score and heightened recovery in finishers. A simultaneous increase in depressed mood, anger, tension-anxiety, and confusion might harm performance and lead to race failure.

Changes in adipokine concentrations in antidepressant-resistant bipolar depression after ketamine infusion and electroconvulsive therapy

OBJECTIVES

This study attempts to assess the concentration of two opposite-acting adipokines (anti-inflammatory adiponectin and pro-inflammatory resistin) in antidepressant-resistant patients undergoing ketamine infusion (KI) and electroconvulsive therapy (ECT).

METHODS

The study group comprised 52 patients hospitalised due to episodes of depression in the course of bipolar disorders. The Hamilton depression scale was used to assess the intensity of the depression symptoms before starting therapy and one day after its completion. The serum concentration of adipokines was determined before and after the therapeutic intervention using an ELISA method.

RESULTS

Baseline adipokine levels differed between patients receiving KI and ECT therapy. Regardless of the procedure used, these levels changed after treatment, with the nature of these changes being different. In the case of KI, the adiponectin levels increased, and resistin levels decreased. In contrast, after ECT, the concentrations of both adipokines decreased. Changes in adipokine concentrations correlated with improvement in mental status, as assessed by the Hamilton Rating Scale, type of bipolar disorder, and gender.

CONCLUSIONS

Adipokines remain interesting candidate biomarkers in assessing the state and course of the disease depending on the therapeutic procedure applied. However, the relatively small study group and limited original research available for discussion justify further investigation.

Impact of Alexithymia on the Lipid Profile in Major Depressed Individuals

Background

The cooccurrence of major depression and dyslipidaemia is associated with negative cardiovascular outcome, which seems to justify a better identification of the factors favouring the development of dyslipidaemia in major depressed individuals. In the literature, there are arguments in favour of a special relationship between dyslipidaemia and alexithymia. However, despite a high prevalence of alexithymia in major depressed individuals, no study has investigated the impact of this personality trait on the lipid profile in this particular subpopulation. Given these elements, the aim of this study was therefore to investigate the risk of dyslipidaemia associated with alexithymia in major depressed individuals to allow better cardiovascular prevention in this subpopulation. Subjects and Methods. Demographic and polysomnographic data from 242 major depressed individuals recruited from the clinical database of the sleep laboratory were analysed. Only individuals with a diagnosis of dyslipidaemia according to the diagnostic criteria of the International Diabetes Federation at admission were included in the “dyslipidaemia” group. Logistic regression analyses were used to determine the risk of dyslipidaemia associated with alexithymia in major depressed individuals.

Results

The prevalence of dyslipidaemia was 43.8% in our sample of major depressed individuals. After adjusting for the main confounding factors, multivariate logistic regression analyses demonstrated that alexithymia was a risk factor for dyslipidaemia in major depressed individuals.

Conclusions

In this study, we found that alexithymia is a risk factor for dyslipidaemia in major depressed individuals, which seems to justify better identification and adequate management of this personality trait in order to allow a better lipid profile in this subpopulation at high cardiovascular risk.

Metabolic proteins at birth predict early childhood mental health symptoms

Child mental health disorders are the leading cause of disability in children and adolescents worldwide. Biological correlates predict psychosocial outcomes throughout human development; however, less is known about metabolic proteins. Drawing from a longitudinal birth cohort study, Born in Bradford (BiB), we examined the role of infant metabolic proteins at birth in predicting early childhood mental health symptoms at 3 and 5 years. We found that higher leptin predicted more prosocial behavior at age 3. Additionally, a higher leptin-to-adiponectin ratio predicted increased total symptom difficulties. At age 5, we found that higher adiponectin predicted a decreased likelihood of being rated by teachers as meeting or exceeding expectations in the domain of "managing feelings and behaviors" and marginally predicted lower competency in "making relationships" on national developmental milestone evaluations. To our knowledge, this is among the first few studies to prospectively predict mental health symptoms from cord blood metabolic proteins, and the first examining this association with a leptin-to-adiponectin ratio. Our results provide support for the possibility that metabolic proteins at birth forecast risk for mental health symptoms in early childhood.

Evaluation of inflammatory and metabolic impairments regarding depression dimensions: a case control study

Background

Patients with depression are at a higher risk of developing serious medical problems such as diabetes mellitus, hypertension, and cardiovascular diseases, increasing the burden of depression and worsening its outcome.

Recent studies revealed the presence of low-grade systemic inflammation and metabolic impairments which are playing an important role in the development of these medical problems among patients with depression.

It should be noted that not all patients with depressive disorder have these immune or metabolic impairments.

The study aims to evaluate inflammatory and metabolic impairments among patients with depression through categorizing patients with depression into four dimensional profilers which are (1) atypical energy-related symptom dimension, (2) melancholic dimension, (3) childhood trauma dimension, and (4) anxious distress dimension.

Also, the current study will evaluate inflammatory and metabolic impairments among patients with depression and a control group.

Results

This study highlights that of the patients with metabolic impairments (including hypertension, impaired glycemic control, low/high-density lipoprotein, elevated triglycerides, and central obesity), all of them had reported significantly higher scores in the atypical, energy-related symptom dimension.

Also, patients with impaired glycemic control had reported significantly (p < 0.001) high scores in the anxious distress symptom dimension.

While patients with inflammatory impairment (serum CRP > 3 mg/L) had significantly (p = 0.009) reported higher scores in the childhood trauma symptom dimension.

In addition, statistically significant metabolic and inflammatory impairments are detected among the depression cases group in comparison with the control group.

Conclusions

This study found that patients with depression presented by atypical, energy-related symptoms were at a higher risk of metabolic impairments than other depression profilers.

Also, patients of the Anxious distress symptom dimension reported significant impaired glycemic control.

In addition, patients with depression of the childhood trauma dimension were associated with high levels of inflammatory marker (C-reactive protein).

Potential implications

These results can be applied clinically to improve treatment and prognosis in patients with depression. For example, depressed patients with atypical, energy-related symptoms should increase their daily physical activities and exercise, and they should follow a special diet. Also, anti-inflammatory medications could be added to depressed patients of the childhood trauma dimension.

An overview of the molecular and physiological antidepressant mechanisms of physical exercise in animal models of depression

BACKGROUND

Depression is a global disease that affects the physical and mental health of people of all ages. Non-pharmacological and unconventional methods of treatment, such as regular physical exercise, have been recommended to treat depression.

METHODS

Here, we briefly review the literature about the physiological and molecular mechanisms of exercise antidepressants in depressive-like behavior in animal models of depression.

RESULTS

The main hysiological and molecular mechanisms of physical exercise in depression include blood flow changes in several areas of the brain, increase in brain serotonin synthesis, increase in antioxidant enzymes, increase in serum and brain brain-derived neuro factor (BDNF) levels, decrease in cortisol levels and reduced inflammation in peripheral and brain tissues. Physical exercise also leads to increased activation of the phosphatidylinositol-3-kinase (PI3K), PGC-1α/FNDC5/Irisin pathway, BDNF concentrations (serum and cerebral), extracellular signal-regulated kinase and cAMP-response element binding protein (mainly in neurons of the hippocampus and prefrontal cortex), which together contribute to fight or inhibit the development of depression symptoms. These molecular and physiological mechanisms work in synchrony, further enhancing their effects.

CONCLUSION

Physical exercise can be used as a safe and effective non-pharmacological treatment in depression.

The Impact of Cognitive Behavioral Therapy on Peripheral Interleukin-6 Levels in Depression: A Systematic Review and Meta-Analysis

There is interest in the role of peripheral interleukin-6 (IL-6) in depression and the effect of treatment (e. g., pharmacologic, psychosocial, neurostimulation). However, the relationship between cognitive behavioral therapy (CBT), IL-6 and depression has not yet been established. We conducted a meta-analysis to explore the association between CBT and change of peripheral IL-6 levels in depressive symptoms or major depressive disorder (MDD). A systematic search of online databases (i.e., PubMed, Web of Science, Google Scholar, PsycINFO, and Cochrane Library) was completed from inception to May 2021. In total, 10 eligible papers with 940 participants reporting peripheral IL-6 levels before and after CBT were included in the analysis. The main result indicates that peripheral levels of IL-6 were significantly lower after CBT intervention in individuals with depression, with a small effect (SMD = 0.38, 95% CI: 0.07, 0.69, p = 0.02). The results of subgroup analyses demonstrate that (1) there was a significant decrease in IL-6 for studies that were equal to or <8 weeks in duration vs. more than 8 weeks in duration, and (2) IL-6 was significantly reduced in the Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnosis (i.e., DSM-IV, DSM-IV-TR, or DSM-V) of MDD, but not for the subgroup without DSM diagnosis. Publication year was identified as a potential contributor to heterogeneity of the results from our analysis. Taken together, our findings support the notion that CBT influences peripheral IL-6 in individuals with depression and represents a point of commonality with other antidepressant treatment modalities (e.g., antidepressants).

SYSTEMATIC REVIEW REGISTRATION

https://doi.org/10.17605/osf.io/tr9yh, identifier: 10.17605/osf.io/tr9yh.

The role of leptin in indirectly mediating "somatic anxiety" symptoms in major depressive disorder

BACKGROUND

Leptin is a multifunctional hormone secreted from adipose tissue, which plays a core role in regulating energy intake and expenditure. Evidence has demonstrated that leptin receptors are located in brain areas involved in emotional processing, and major depressive disorder (MDD) is characterized by dysfunction of emotional processing. Taken together, these features suggest that leptin may play a potential role in the pathophysiology of MDD. However, the precise roles of leptin in modulating depressive symptoms in MDD remain unclear.

METHODS

Participants [18 drug-naïve MDD patients, 15 unaffected first-degree relatives of MDD patients (FDR-MDD), and 40 healthy controls] completed clinical assessments and provided blood samples for measurement of leptin levels. We evaluated the effect of leptin on clinical status (MDD or FDR-MDD) and symptomatic dimensionalities of MDD using mediation analysis.

RESULTS

We found that leptin was increased in MDD patients and this only predicted "somatic anxiety" symptoms. Furthermore, leptin was a significant and indirect mediator of the association between clinical status (MDD or FDR-MDD) and "somatic anxiety" symptoms.

CONCLUSION

Our finding that leptin was a significant and indirect mediator of clinical status (MDD or FDR-MDD) and "somatic anxiety" symptoms suggests that leptin may indirectly affect somatic depressive symptoms in MDD. Our findings may provide a theoretical basis for novel clinical interventions in MDD.

Leptin-A Potential Bridge between Fat Metabolism and the Brain's Vulnerability to Neuropsychiatric Disorders: A Systematic Review

BACKGROUND

Obesity and being overweight have been described as potential causes of neurological disorders. Leptin, a peptide expressed in fat tissue, importantly participates in energy homeostasis and storage and has recently been identified for its signaling receptors in neuronal circuits of the brain.

AIM

To elucidate whether the endogenous modulation of leptin can be a protection against neuropsychiatric disorders.

METHOD

A systematic review was performed in accordance with the PRISMA-P method, and reports of studies containing data of leptin concentrations in healthy individuals with or without obesity were retrieved from the PubMed database, using the combinations of Mesh terms for "Leptin" and "Metabolism".

RESULTS

Forty-seven randomized and non-randomized controlled trials, dating from 2000 to 2021, were included in the qualitative synthesis.

DISCUSSION AND CONCLUSIONS

Leptin secretion displays a stabilizing pattern that is more sensitive to a negative energy intake imbalance. Leptin levels influence body weight and fat mass as a pro-homeostasis factor. However, long-term exposure to elevated leptin levels may lead to mental/behavioral disorders related to the feeding and reward systems.

Adiponectin predicts poor response to antidepressant drugs in major depressive disorder

OBJECTIVE

Produced by adipocytes, adiponectin crosses the blood-brain barrier to bind with specific receptors in the hypothalamus, brainstem, hippocampus, and cortex. In patients with major depressive disorder (MDD), circulating levels of adiponectin inversely related with antidepressant response to ketamine, and predicted a better response to multi-target drug combinations than to escitalopram. We investigated the effect of adiponectin on response to antidepressants in a naturalistic setting.

METHODS

We assessed baseline plasma levels of adiponectin in 121 MDD inpatients, treated with antidepressant drug monotherapy based on clinical need (selective serotonin reuptake inhibitors, venlafaxine, duloxetine) in a specialized hospital setting. Severity of depression was weekly assessed with Hamilton scale ratings.

RESULTS

Adiponectin plasma levels were higher in patients with MDD compared with healthy controls, and negatively influenced the pattern of antidepressant response (higher baseline levels, worse response) independent of the drug class and of the baseline severity of depression, and of age, sex, and body mass index.

CONCLUSIONS

The identification of adiponectin as a predictor of antidepressant response to drugs of different mechanism of action, such as ketamine, SSRIs, and SNRIs, and both in experimental and in clinical settings, warrants interest for further study of its pathways to search for novel biomarkers and therapeutic targets.

Gut hormones, adipokines, and pro- and anti-inflammatory cytokines/markers in loss of control eating: A scoping review

Loss of control (LOC) eating is the defining feature of binge-eating disorder, and it has particular relevance for bariatric patients. The biomarkers of LOC eating are unclear; however, gut hormones (i.e., ghrelin, cholecystokinin [CCK], peptide YY [PYY], glucagon-like peptide 1 [GLP-1], and pancreatic polypeptide [PP]), adipokines (i.e., leptin, adiponectin), and pro- and anti-inflammatory cytokines/markers (e.g., high-sensitivity C-reactive protein [hsCRP]) are candidates due to their involvement in the psychophysiological mechanisms of LOC eating. This review aimed to synthesize research that has investigated these biomarkers with LOC eating. Because LOC eating is commonly examined within the context of binge-eating disorder, is sometimes used interchangeably with subclinical binge-eating, and is the latent construct underlying disinhibition, uncontrolled eating, and food addiction, these eating behaviors were included in the search. Only studies among individuals with overweight or obesity were included. Among the identified 31 studies, 2 studies directly examined LOC eating and 4 studies were conducted among bariatric patients. Most studies were case-control in design (n = 16) and comprised female-dominant (n = 13) or female-only (n = 13) samples. Studies generally excluded fasting total ghrelin, fasting CCK, fasting PYY, and fasting PP as correlates of the examined eating behaviors. However, there was evidence that the examined eating behaviors were associated with lower levels of fasting acyl ghrelin (the active form of ghrelin) and adiponectin, higher levels of leptin and hsCRP, and altered responses of postprandial ghrelin, CCK, and PYY. The use of GLP-1 analog was able to decrease binge-eating. In conclusion, this review identified potential biomarkers of LOC eating. Future studies would benefit from a direct focus on LOC eating (especially in the bariatric population), using longitudinal designs, exploring potential mediators and moderators, and increased inclusion of the male population.

Leptin polymorphism rs3828942: risk for anxiety disorders?

Leptin is an anorexigenic hormone well recognized by its role in mediating energy homeostasis. Recently, leptin has been associated with psychiatric disorders and interestingly, leptin treatment has shown antidepressant and anxiolytic effects. We examined the association of leptin levels and leptin (LEP) gene rs3828942 polymorphism with anxiety disorders considering sex differences. A cross-sectional population-based study, including 1067 young adults, of whom 291 presented anxiety disorders diagnosed by the Mini International Neuropsychiatric Interview (MINI 5.0). The rs3828942 polymorphism was genotyped by real-time PCR and ELISA measured leptin levels. Leptin levels were not associated with anxiety disorders after adjusting for sex and body mass index (BMI) [ß = - 0.009 (- 0.090-0.072); p = 0.832]. The distribution of rs3828942 genotypes was not associated with anxiety disorders. However, in a sex-stratified sample, the A-allele of rs3828942 polymorphism was associated with risk for GAD in women even when adjusting for confounding variables [OR = 1.87 (1.17-2.98); p = 0.008]. In a subsample of 202 individuals with GAD and control matched by sex and BMI, results suggest an interaction between genotypes and GAD diagnosis based on leptin levels only in the male group [F (1, 54) = 6.464; p = 0.0139]. Leptin is suggested to be related with the neurobiology of anxiety disorders in a sex-dependent manner since women carrying the A-allele of LEP rs3828942 present a higher risk for GAD, while leptin levels seem to be lower in men with GAD carrying A-allele. Studies on the relationship between leptin polymorphisms and levels are scarce and, therefore, further research is necessary.

Exploring the therapeutic potential of omega-3 fatty acids in depression

Omega-3 fatty acids have been acknowledged for their number of holdings on an individual's health. Not only in physical valuation but also in managing psychiatric disorders, omega-3 fatty acids have been found to be a powerful formula. It is proclaimed that depressive patients suffer anomaly with the levels of omega-3 polyunsaturated fatty acids in the body, coupled with insignificant EPA and DHA. Enhancement in brain functioning, neuronal functions, and paying attention in interacting with the brain cells are some of the additional tasks, being performed by the supplementation of omega-3 fatty acids. The leading and primary source via dietary supplementation involves the involvement of fish and fish products. These are hypothesized to be the best and dominant source for omega-3 fatty acids. Consumption of omega-3 fatty acid is well safe, that physician highly favors intake of these supplements, remarkably in the case of pregnant women. However, treating this serious life-threatening mental disorder leads to many adverse effects when treated with antidepressants. The dose range includes 1g/d to 10g/d, which is to be incorporated by the patient. It is also tested that the combination of EPA and DHA is found to be more efficacious for a person in treating and preventing depressive symptoms. Some studies verify the supplementation of omega-3 fatty acids in diet was coequally productive and successful with minimal side effects when analyzed with antidepressants. Despite these facts, much research is still needed and presently in process for long-term safety and studying the role of omega-3 fatty acids in human health.

Highly Sensitive and Single-Use Biosensing System Based on a GP Electrode for Analysis of Adiponectin, an Obesity Biomarker

This study presents a disposable, novel, and sensitive biosensing system to determine adiponectin, an obesity biomarker, in real human serum. The graphite paper (GP) working electrode is a new material for impedimetric biosensors. In the literature, there is no study in which this electrode is used in impedance-based biosensors for adiponectin detection. Sensitive and useful techniques, such as electrochemical impedance spectroscopy and cyclic voltammetry, were utilized for investigation of the modification of the GP electrode surface and optimization and characterization of the constructed biosensor. The single frequency impedance technique was used to study the interactions between antiadiponectin and adiponectin. The morphology of the electrode surface for each immobilization step was examined with scanning electron microscopy. All experimental parameters were optimized to fabricate a rapid and sensitive biosensing system. The designed biosensor presents excellent performance with a wide detection range (0.05-25 pg mL^-1) and a low limit of detection (0.0033 pg mL^-1) for adiponectin determination. Also, it has been demonstrated that the biosensor sensitively allows for the detection of adiponectin in human serum. The affinity of the designed immunosensor toward other proteins and components was examined in the presence of the target protein (adiponectin), leptin (100 pg mL^-1), creatine kinase (50 pg mL^-1), parathyroid hormone (50 pg mL^-1), and d-glucose (0.5 M). The selectivity of the adiponectin biosensor resulted in high capacity to neglect the interference effect. The constructed biosensor showed good linearity, long-term storage life (10 weeks), high reusability (18 times regenerability), and high ability to detect adiponectin concentrations at picogram levels.

Role of appetite hormone dysregulation in the cognitive function among patients with bipolar disorder and major depressive disorder

OBJECTIVES

The association of appetite hormones with cognitive function in patients with affective disorders remains unknown.

METHODS

All total, 58 adult patients with bipolar I disorder, 36 with bipolar II disorder, 40 with major depressive disorder were enrolled and age and sex-matched with 40 controls. The levels of appetite hormones leptin, ghrelin, insulin and adiponectin were assessed. Wisconsin Card Sorting Test was used to assess executive function.

RESULTS

A general linear model, adjusted for demographic data and clinical symptoms, demonstrated the ghrelin levels were higher in patients with bipolar I or II disorder than in those with major depressive disorder and controls (p < 0.001). We also identified a positive correlation of ghrelin level and executive function among patients with bipolar I (p = 0.033) and II (p = 0.027) disorders, but not among those with major depressive disorder and controls.

CONCLUSIONS

Patients with bipolar I or II disorder were more likely to have high levels of ghrelin than patients with major depressive disorder and controls, which may have a positive correlation on the cognitive function of patients with bipolar I or II disorder.

Neuroticism is positively associated with leptin/adiponectin ratio, leptin and IL-6 in young adults

High neuroticism is related to cardiovascular morbidity. Early detection of metabolic and cardiovascular risk is important in high-risk groups to enable preventive measures. The aim of this study was therefore to explore if neuroticism is associated with early biomarkers for cardiovascular and metabolic disease in young adults from a psychiatry cohort. Blood samples and self-ratings on neuroticism with the Swedish universities Scales of Personality (SSP) questionnaire were collected from 172 psychiatric outpatients and 46 healthy controls. The blood samples were analysed for plasma leptin, adiponectin, CRP, IL-6 and TNF-α. Associations between neuroticism and biomarkers were assessed using Spearman's correlation coefficients and generalized linear models adjusting for confounders. In the adjusted generalized linear models, neuroticism predicted the leptin/adiponectin ratio (p = 0.003), leptin (p = 0.004) and IL-6 (p = 0.001). These associations were not better explained by current major depressive disorder and/or anxiety disorder. Adiponectin, CRP and TNF-α were not associated with neuroticism. In conclusion, the findings suggest that high neuroticism is related to elevated levels of plasma leptin/adiponectin ratio, leptin and IL-6 in young adults. Young adults with high neuroticism may therefore benefit from preventive interventions to decrease the risk for future metabolic and cardiovascular morbidity, but more research is required to test this hypothesis.

Relationships between depression and anxiety symptoms and adipocyte-derived proteins in postmenopausal women

INTRODUCTION

Studies on the association between adiponectin and leptin and anxiety and depression among postmenopausal women are limited. Therefore, the present study specifically evaluates the mutual relationships between adiponectin and leptin and anxiety and depression in postmenopausal women.

PARTICIPANTS AND DESIGN

In this cross-sectional study, a total of 190 women aged 40-65 years were enrolled. Depression symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D), and anxiety symptoms were evaluated using the Hamilton Anxiety Rating Scale (HAM-A). Fasting specimens were collected to measure sex hormone, glucose, insulin, and adipokine levels. Multiple linear regression analysis was performed to evaluate the associations between depression and anxiety and adipocyte-derived hormones.

SETTINGS

The study was performed in a hospital medical center.

RESULTS

Among 190 enrolled postmenopausal women, Spearman's rank correlation analysis revealed significant correlations between CES-D and HAM-A (r = 0.715, P < 0.0001), between CES-D and adiponectin (p = 0.009) and leptin (p = 0.015), and between HAM-A and adiponectin (p = 0.01) and leptin (p = 0.001). The subjects with CES-D ≥ 16 and with HAM-A ≥ 18 had higher adiponectin levels than those with CES-D < 16 and HAM-A < 18, respectively. After adjusting for age, body mass index, exercise, alanine amino transferase and parameters of lipid profiles, Log adiponectin levels were found to be significantly associated with both CES-D and HAM-A, and Log leptin levels were only significantly associated with HAM-A.

CONCLUSIONS

The data show that adiponectin and leptin levels are significantly associated with depression and anxiety symptoms. These results suggest that higher adiponectin and lower leptin levels may serve as potential markers related to anxiety and mood in postmenopausal women. More future research that is designed to deal with the important confounders (e.g., population heterogeneity) is needed to investigate comprehensively on these associations.

Pathophysiology linking depression and type 2 diabetes: Psychotherapy, physical exercise, and fecal microbiome transplantation as damage control

Diabetes increases the likelihood of developing depression and vice versa. Research on this bidirectional association has somewhat managed to delineate the interplay among implicated physiological processes. Still, further exploration is required in this context. This review addresses the comorbidity by investigating suspected common pathophysiological mechanisms. One such factor is psychological stress which disturbs the hypothalamic-pituitary-adrenal axis causing hormonal imbalance. This includes elevated cortisol levels, a common biomarker of both depression and diabetes. Disrupted insulin signaling drives the hampered neurotransmission of serotonin, dopamine, and norepinephrine. Also, adipokine hormones such as adiponectin, leptin, and resistin and the orexigenic hormone, ghrelin, are involved in both depression and T2DM. This disarray further interferes with physiological processes encompassing sleep, the gut-brain axis, metabolism, and mood stability. Behavioral coping mechanisms, such as unhealthy eating, mediate disturbed glucose homeostasis, and neuroinflammation. This is intricately linked to oxidative stress, redox imbalance, and mitochondrial dysfunction. However, interventions such as psychotherapy, physical exercise, fecal microbiota transplantation, and insulin-sensitizing agents can help to manage the distressing condition. The possibility of glucagon-like peptide 1 possessing a therapeutic role has also been discussed. Nonetheless, there stands an urgent need for unraveling new correlating targets and biological markers for efficient treatment.

Dysregulation of kynurenine pathway and potential dynamic changes of kynurenine in schizophrenia: A systematic review and meta-analysis

The kynurenine (KYN) pathway is postulated to play various roles in immune system dysregulation of schizophrenia (SCZ). We conducted a meta-analysis to explore the association between six key metabolites of KYN pathway (i.e., tryptophan (TRP), KYN, quinolinic acid (QUIN), and kynurenic acid (KYNA)) and SCZ. Priori Bonferroni adjustments were conducted for multiple comparisons. In total, 42 studies that examined the relationship between the metabolites in KYN pathway mentioned above and SCZ in 4217 participants and nine studies that examined alterations of these metabolites after antipsychotic treatments were included. The results demonstrate that (1) subjects with prescribed medication had significantly higher KYN levels when compared to controls; (2) higher KYN levels in cerebrospinal fluid (CSF), lower plasma KYN levels and higher CSF KYNA levels were associated with SCZ; (3) the KYN levels were higher in subjects with SCZ after antipsychotic treatments when compared with baseline. The evidence provides valuable insight of the potential underlying involvement of the KYN pathway in the pathogenesis of SCZ.

Mechanisms Underlying the Cognitive and Behavioural Effects of Maternal Obesity

The widespread consumption of 'western'-style diets along with sedentary lifestyles has led to a global epidemic of obesity. Epidemiological, clinical and preclinical evidence suggests that maternal obesity, overnutrition and unhealthy dietary patterns programs have lasting adverse effects on the physical and mental health of offspring. We review currently available preclinical and clinical evidence and summarise possible underlying neurobiological mechanisms by which maternal overnutrition may perturb offspring cognitive function, affective state and psychosocial behaviour, with a focus on (1) neuroinflammation; (2) disrupted neuronal circuities and connectivity; and (3) dysregulated brain hormones. We briefly summarise research implicating the gut microbiota in maternal obesity-induced changes to offspring behaviour. In animal models, maternal obesogenic diet consumption disrupts CNS homeostasis in offspring, which is critical for healthy neurodevelopment, by altering hypothalamic and hippocampal development and recruitment of glial cells, which subsequently dysregulates dopaminergic and serotonergic systems. The adverse effects of maternal obesogenic diets are also conferred through changes to hormones including leptin, insulin and oxytocin which interact with these brain regions and neuronal circuits. Furthermore, accumulating evidence suggests that the gut microbiome may directly and indirectly contribute to these maternal diet effects in both human and animal studies. As the specific pathways shaping abnormal behaviour in offspring in the context of maternal obesogenic diet exposure remain unknown, further investigations are needed to address this knowledge gap. Use of animal models permits investigation of changes in neuroinflammation, neurotransmitter activity and hormones across global brain network and sex differences, which could be directly and indirectly modulated by the gut microbiome.

The Association Between Concentrations of Arginine, Ornithine, Citrulline and Major Depressive Disorder: A Meta-Analysis

Alterations in the peripheral (e.g., serum, plasma, platelet) concentrations of arginine and its related catabolic products (i.e., ornithine, citrulline) in the urea and nitric oxide cycles have been reported to be associated with major depressive disorder (MDD). The meta-analysis herein aimed to explore the association between the concentration of peripheral arginine, its catabolic products and MDD, as well as to discuss the possible role of arginine catabolism in the onset and progression of MDD. PubMed, EMBASE, PsycINFO and Web of Science were searched from inception to June 2020. The protocol for the meta-analysis herein has been registered at the Open Science Framework [https://doi.org/10.17605/osf.io/7fn59]. In total, 745 (47.5%) subjects with MDD and 823 (52.5%) healthy controls (HCs) from 13 articles with 16 studies were included. Fifteen of the included studies assessed concentrations of peripheral arginine, eight assessed concentrations of ornithine, and six assessed concentrations of citrulline. Results indicated that: (1) the concentrations of arginine, ornithine, and citrulline were not significantly different between individuals with MDD and HCs when serum, plasma and platelet are analyzed together, (2) in the subgroups of serum samples, the concentrations of arginine were lower in individuals with MDD than HCs, and (3) concurrent administration of psychotropic medications may be a confounding variable affecting the concentrations of arginine, ornithine, and citrulline. Our findings herein do not support the hypothesis that arginine catabolism between individuals with MDD and HCs are significantly different. The medication status and sample types should be considered as a key future research avenue for assessing arginine catabolism in MDD.

Evaluation of Stress and Associated Biochemical Changes in Patients with Type 2 Diabetes Mellitus and Obesity

PURPOSE

Type 2 diabetes mellitus (T2DM), a metabolic disorder, remains associated with a physiological impairment affecting large populations worldwide. Onset of T2DM is multifactorial where obesity and abnormal basal metabolic rate are considered most critical. Of people diagnosed with T2DM, about 80% are also obese. It is also reported that obese individuals have an increased odds of developing depression, whereas T2DM is estimated to increase the incidence by two-fold. The preponderance of research data demonstrates that T2DM alters the serum level of cortisol and adiponectin which are known to be associated with neuronal physiology. The study explored, how a metabolic disorder like T2DM is linked with the altered plasma level of cortisol and adiponectin, the risk factors for stress and depression.

PATIENTS AND METHODS

A cross-sectional population study was conducted in T2DM patients using a bimodal approach. First approach used questionnaires, (1) Patient Health Questionnaire (PHQ-9) and (2) Stress Coping Inventory Questionnaire (SCQ) to assess signs and symptoms of depression and stress, respectively, in T2DM patients. In the second approach, robust biochemical analysis was conducted for serum adiponectin and cortisol levels.

RESULTS

An association of T2DM in stress and depression was evaluated in 158 subjects (105 T2DM obese patients and 53 healthy controls). A lower PHQ-9 score and adiponectin levels were seen in T2DM obese patients compared to healthy controls (p<0.05). Further, results also depicted a lower adiponectin levels in T2DM obese patients with depression compared to T2DM obese patients without depression (p<0.05). The study did not find a significant difference in cortisol serum levels among the T2DM and control groups. However, a higher level of serum cortisol was reported in T2DM obese patients with depression over those T2DM obese patients who lacked depression (p<0.05).

CONCLUSION

The findings suggest that T2DM obese patients might have a higher risk of developing stress and depression. Further, biochemical parameters, adiponectin and cortisol, might be the potential biomarkers for T2DM and may help in early diagnosis of these comorbid conditions.

Depression and Cardiovascular Disease: The Viewpoint of Platelets

Depression is a major cause of morbidity and low quality of life among patients with cardiovascular disease (CVD), and it is now considered as an independent risk factor for major adverse cardiovascular events. Increasing evidence indicates not only that depression worsens the prognosis of cardiac events, but also that a cross-vulnerability between the two conditions occurs. Among the several mechanisms proposed to explain this interplay, platelet activation is the more attractive, seeing platelets as potential mirror of the brain function. In this review, we dissected the mechanisms linking depression and CVD highlighting the critical role of platelet behavior during depression as trigger of cardiovascular complication. In particular, we will discuss the relationship between depression and molecules involved in the CVD (e.g., catecholamines, adipokines, lipids, reactive oxygen species, and chemokines), emphasizing their impact on platelet activation and related mechanisms.

Depression Heterogeneity and Its Biological Underpinnings: Toward Immunometabolic Depression

Epidemiological evidence indicates the presence of dysregulated homeostatic biological pathways in depressed patients, such as increased inflammation and disrupted energy-regulating neuroendocrine signaling (e.g., leptin, insulin). Alterations in these biological pathways may explain the considerable comorbidity between depression and cardiometabolic conditions (e.g., obesity, metabolic syndrome, diabetes) and represent a promising target for intervention. This review describes how immunometabolic dysregulations vary as a function of depression heterogeneity by illustrating that such biological dysregulations map more consistently to atypical behavioral symptoms reflecting altered energy intake/expenditure balance (hyperphagia, weight gain, hypersomnia, fatigue, and leaden paralysis) and may moderate the antidepressant effects of standard or novel (e.g., anti-inflammatory) therapeutic approaches. These lines of evidence are integrated in a conceptual model of immunometabolic depression emerging from the clustering of immunometabolic biological dysregulations and specific behavioral symptoms. The review finally elicits questions to be answered by future research and describes how the immunometabolic depression dimension could be used to dissect the heterogeneity of depression and potentially to match subgroups of patients to specific treatments with higher likelihood of clinical success.

Depression profilers and immuno-metabolic dysregulation: Longitudinal results from the NESDA study

BACKGROUND

Major depressive disorder (MDD) is linked to higher cardio-metabolic comorbidity that may in part be due to the low-grade inflammation and poorer metabolic health observed in MDD. Heterogeneity of MDD is however large, and immune-inflammatory and metabolic dysregulation is present in only part of the MDD cases. We examined the associations of four depression dimensional profilers (atypical energy-related symptom dimension, melancholic symptom dimension, childhood trauma severity, and anxious distress symptom dimension) with immuno-metabolic outcomes, both cross-sectionally and longitudinally.

METHODS

Three waves covering a 6-year follow-up (>7000 observations) of the Netherlands Study of Depression and Anxiety (NESDA) were used. Depression profilers were based on the Inventory of Depressive Symptomatology, the Beck Anxiety Inventory, and the Childhood Trauma index. An inflammatory index (based on IL-6 and CRP), a metabolic syndrome index (based on the five metabolic syndrome components), and a combination of these two indices were constructed. Mixed models were used for cross-sectional and longitudinal models, controlling for covariates.

RESULTS

Of the four depression profilers, only the atypical, energy-related symptom dimension showed robust associations with higher scores on the inflammatory, metabolic syndrome and combined inflammatory-metabolic indexes cross-sectionally, as well as at follow-up. The melancholic symptom dimension was associated with lower scores on the metabolic syndrome index both cross-sectionally and longitudinally.

CONCLUSION

The atypical energy-related symptom dimension was linked to poorer immune-inflammatory and metabolic health, while the melancholic symptom dimension was linked to relatively better metabolic health. Persons with high atypical energy-related symptom burden, representing an immuno-metabolic depression, may be the most important group to target in prevention programs for cardiometabolic disease, and may benefit most from treatments targeting immuno-metabolic pathways.

The impact of chronic stress on energy metabolism

The brain is exceptionally demanding in terms of energy metabolism. Approximately 20% of the calories consumed are devoted to our cerebral faculties, with the lion's share provided in the form of glucose. The brain's stringent energy dependency requires a high degree of harmonization between the elements responsible for supplying- and metabolizing energetic substrates. However, chronic stress may jeopardize this homeostatic energy balance by disruption of critical metabolic processes. In agreement, stress-related mental disorders have been linked with perturbations in energy metabolism. Prominent stress-induced metabolic alterations include the actions of hormones, glucose uptake and mitochondrial adjustments. Importantly, fundamental stress-responsive metabolic adjustments in humans and animal models bear a striking resemblance. Here, an overview is provided of key findings, demonstrating the pervasive impact of chronic stress on energy metabolism. Furthermore, I argue that medications, aimed primarily at restoring metabolic homeostasis, may constitute a novel approach to treat mental disorders.

Association between arginine catabolism and major depressive disorder: A protocol for the systematic review and meta-analysis of metabolic pathway

BACKGROUND

Alterations in the levels of arginine and its related catabolic products (ie, ornithine, citrulline, and argininosuccinate) in the urea and nitric oxide cycles were reported to play roles in the pathogenesis of major depressive disorder (MDD). The aim of this meta-analysis study is to explore the associations between arginine with its related catabolic products and MDD, and to discuss the possible role of arginine catabolism in the pathoetiology of MDD.

METHODS

This study will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The English language literature published in the databases of PubMed, EMBASE, PsycINFO and Web of Science will be systematically searched. Forest plots will be used to estimate the associations between arginine and its related catabolic products with MDD. Subgroup analysis and meta-regression will also be performed to investigate the source of the potential heterogeneity. Sensitivity analysis will be performed to strengthen the results and to investigate whether any single study would have a significant effect on the results of meta-analysis. Publication bias will be tested for using the funnel plot with Begg test and Egger test. The Newcastle-Ottawa Scale will be applied to assess the risk of bias of observational studies.

RESULTS

An integrated assessment of arginine with its related catabolic products may contribute to predict the risk of MDD.

ETHICS AND DISSEMINATION

The results of associations between arginine with its related catabolic products and MDD will be reported in a peer-reviewed publication. With our findings from this meta-analysis, we hope to provide the most up-to-date evidence for the contributions of arginine and related catabolic products to predict the risk of MDD.

SYSTEMATIC REVIEW REGISTRATION

The protocol of current meta-analysis has been registered at the Open Science Framework [Available at: https://doi.org/10.17605/osf.io/7fn59].

Evidence-based umbrella review of 162 peripheral biomarkers for major mental disorders

The literature on non-genetic peripheral biomarkers for major mental disorders is broad, with conflicting results. An umbrella review of meta-analyses of non-genetic peripheral biomarkers for Alzheimer's disease, autism spectrum disorder, bipolar disorder (BD), major depressive disorder, and schizophrenia, including first-episode psychosis. We included meta-analyses that compared alterations in peripheral biomarkers between participants with mental disorders to controls (i.e., between-group meta-analyses) and that assessed biomarkers after treatment (i.e., within-group meta-analyses). Evidence for association was hierarchically graded using a priori defined criteria against several biases. The Assessment of Multiple Systematic Reviews (AMSTAR) instrument was used to investigate study quality. 1161 references were screened. 110 met inclusion criteria, relating to 359 meta-analytic estimates and 733,316 measurements, on 162 different biomarkers. Only two estimates met a priori defined criteria for convincing evidence (elevated awakening cortisol levels in euthymic BD participants relative to controls and decreased pyridoxal levels in participants with schizophrenia relative to controls). Of 42 estimates which met criteria for highly suggestive evidence only five biomarker aberrations occurred in more than one disorder. Only 15 meta-analyses had a power >0.8 to detect a small effect size, and most (81.9%) meta-analyses had high heterogeneity. Although some associations met criteria for either convincing or highly suggestive evidence, overall the vast literature of peripheral biomarkers for major mental disorders is affected by bias and is underpowered. No convincing evidence supported the existence of a trans-diagnostic biomarker. Adequately powered and methodologically sound future large collaborative studies are warranted.

Seasonal affective disorder and seasonal changes in weight and sleep duration are inversely associated with plasma adiponectin levels

Overlapping pathways between mood and metabolic regulation have increasingly been reported. Although impaired regulation of adiponectin, a major metabolism-regulating hormone, has been implicated in major depressive disorder, its role in seasonal changes in mood and seasonal affective disorder-winter type (SAD), a disorder characterized by onset of mood impairment and metabolic dysregulation (e.g., carbohydrate craving and weight gain) in fall/winter and spontaneous alleviation in spring/summer, has not been previously studied. We studied a convenience sample of 636 Old Order Amish (mean (± SD), 53.6 (±14.8) years; 50.1% males), a population with self-imposed restriction on network electric light at home, and low prevalence of total SAD (t-SAD = syndromal + subsyndromal). We calculated the global seasonality score (GSS), estimated SAD and subsyndromal-SAD after obtaining Seasonal Pattern Assessment Questionnaires (SPAQs), and measured overnight fasting plasma adiponectin levels. We then tested associations between plasma adiponectin levels and GSS, t-SAD, winter-summer difference in self-reported sleep duration, and self-reported seasonal weight change, by using analysis of co-variance (ANCOVA) and linear regression analysis after adjusting for age, gender, and BMI. Participants with t-SAD (N = 14; 2.2%) had significantly lower plasma adiponectin levels (mean ± SEM, 8.76 ± 1.56 μg/mL) than those without t-SAD (mean ± SEM, 11.93 ± 0.22 μg/mL) (p = 0.035). In addition, there was significant negative association between adiponectin levels and winter-summer difference in self-reported sleep duration (p = 0.025) and between adiponectin levels and self-reported seasonal change in weight (p = 0.006). There was no significant association between GSS and adiponectin levels (p = 0.88). To our knowledge, this is the first study testing the association of SAD with adiponectin levels. Replication and extension of our findings longitudinally and, then, interventionally, may implicate low adiponectin as a novel target for therapeutic intervention in SAD.