Appetite changes reveal depression subgroups with distinct endocrine, metabolic, and immune states

Inflammatory cytokines and appetite in older hospitalized patients

It has already been confirmed that the decline in appetite during disease is a common issue and the biologic players of inflammation such as cytokines may serve as mediators of this effect. This study aimed to investigate the association of appetite with individual cytokines that could be involved in the inflammation-associated loss of appetite in acutely ill older hospitalized patients. 191 patients (mean age 81.3 ± 6.6 years, 64% women) participated in this prospective observational study. Risk of malnutrition and patient's appetite were evaluated using the Mini Nutritional Assessment Short Form and the Simplified Nutritional Appetite Questionnaire on admission, respectively. Serum C-reactive protein (CRP) and serum cytokines such as Interleukin 1 beta (IL-1β), IL-6, IL-8, IL-10, IL-12p70, IL-17, IL-18, IL-23 and IL-33, interferon alpha-2, interferon gamma, tumor necrosis factor alpha and monocyte chemoattractant protein-1 (MCP-1) were measured. Of total population, 30% had CRP>3.0 (mg/dL), 31% were malnourished and 31% demonstrated poor and very poor appetite. There were significant differences in the mean concentrations of a number of cytokines including IL-1β, MCP-1, IL-6, IL-10, IL-12p70, IL-18 and IL-23 across the appetite scores. In a regression analysis, an increased IL-18 level (P = 0.049) was the most prominent biomarker for poor appetite. No other significant associations between appetite and circulating levels of other cytokines were found in the regression analysis, except for IL-6 and IL-33, which were only significantly associated in the unadjusted model. The association of IL-18 with decreased appetite was independent from the severity of CRP-level and infections. In this study, certain cytokines, in particular IL-18 were associated with poor appetite in acutely diseased patients and should therefore be considered as a potential target of the prevention and treatment of malnutrition.

Prevalence, awareness, treatment, and control of diabetes mellitus by depressive symptom severity: a cross-sectional analysis of NHANES 2011-2016

INTRODUCTION

Despite extensive studies on the relationship between diabetes mellitus (DM) and depression, the associations of depressive symptom severity with prevalence, awareness, treatment, and control of diabetes remain unclear. We aimed to investigate changes in these outcomes of diabetes as depressive symptoms aggravate.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional analysis of 14 328 participants in the 2011-2016 National Health and Nutrition Examination Survey. Participants were classified into depressive symptom groups of none, mild, moderate, moderately severe, and severe depending on their Patient Health Questionnaire-9 scores. Multivariate logistic regression analyses were conducted in three models adjusted for expanding confounders to evaluate the associations between severity of depressive symptoms and prevalence, awareness, treatment, and control of DM.

RESULTS

As depressive symptom severity worsened, both prevalence and awareness of DM increased regardless of models (p value for trend <0.01 in all models for prevalence and awareness; adjusted OR (aOR) 2.14, 95% CI 1.29 to 3.56 for prevalence in the severe group, model 1; aOR 2.43, 95% CI 1.27 to 4.64 for awareness in the moderately severe group, model 1). Notwithstanding higher awareness of diabetes in the moderately severe and severe groups (84.5% and 86.2%, respectively, vs 71.3% in the none group), these groups were treated less (aOR 0.25, 95% CI 0.11 to 0.55 in the severe group, model 3) or inadequately controlled (aOR 0.51, 95% CI 0.27 to 0.98 in the moderately severe group, model 3).

CONCLUSIONS

The gap between patients' higher awareness and lower treatment rate or control of diabetes among individuals with severe depressive symptoms highlights the unmet needs for postdiagnostic multidisciplinary care for patients with comorbid depression and DM.

Assessment of Factors Related to Diminished Appetite in Hemodialysis Patients with a New Adapted and Validated Questionnaire

Appetite loss is a common phenomenon in end-stage renal disease (ESRD) patients undergoing maintenance hemodialysis (HD). We aimed to (i) adapt and validate a Spanish language version of the Council on Nutrition Appetite Questionnaire (CNAQ) and (ii) to identify psychological and biological factors associated with diminished appetite. We recruited 242 patients undergoing HD from four hemodialysis centers to validate the Spanish-translated version of the CNAQ. In another set of 182 patients from three HD centers, the Appetite and Diet Assessment Tool (ADAT) was used as the gold standard to identify a cut-off value for diminished appetite in our adapted questionnaire. The Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Distorted Thoughts Scale (DTS), Dialysis Malnutrition Score (DMS), anthropometric, values and laboratory values were also measured. Seven items were preserved in the adapted appetite questionnaire, with two factors associated with flavor and gastric fullness (Cronbach’s alpha = 0.758). Diminished appetite was identified with a cut-off value ≤25 points (sensitivity 73%, specificity 77%). Patients with diminished appetite had a higher proportion of females and DMS punctuation, lower plasmatic level of creatinine, blood urea nitrogen, and phosphorus. Appetite score correlated with BDI score, BAI score and DTS. Conclusions: This simple but robust appetite score adequately discriminates against patients with diminished appetite. Screening and treatment of psychological conditions may be useful to increase appetite and the nutritional status of these patients.

Prevalence and characteristics of starvation-related malnutrition in a mid-Atlantic healthcare system: A cohort study

BACKGROUND

Malnutrition in the hospital negatively impacts outcomes, including readmissions, mortality, and cost. Starvation-related malnutrition (SRM) is a state of chronic undernutrition with little to no inflammation. Research on SRM within the hospital setting is lacking. Our objective was to determine the prevalence and characteristics of malnutrition within the hospital, focusing on characteristics associated with readmissions in those with SRM.

METHODS

We conducted a retrospective cohort study analyzing characteristics of adult in patients with acute disease-related malnutrition (ADM) and chronic disease-related malnutrition (CDM) compared with patients with SRM. Prevalence of all malnutrition types was calculated as the total number of malnourished patients divided by the total number of hospital discharges. Analysis of variance with Tukey post hoc analysis was performed to determine differences between characteristics of patients with SRM and other forms of malnutrition.

RESULTS

Total prevalence of malnutrition was 2.8%. Of malnourished patients, 17.6%, 79.9%, and 2.5% had ADM, CDM, and SRM, respectively. Patients with SRM had lower body mass index (BMI) (P < .001) and higher rates of readmission (P = 0.046), infectious disease (P < .001), psychiatric disease (P < .001), and substance abuse (P < .001) than patients with ADM or CDM. Readmitted patients with SRM had lower BMI and higher rates of infection and drug abuse than those without readmission.

CONCLUSION

The high incidence of comorbid substance abuse and mental illness in patients with SRM provide important targets for treatment that might reduce readmission and improve outcomes.

The concept of anorexia of aging in late life depression: A cross-sectional analysis of a cohort study

INTRODUCTION

Anorexia of aging (AA) is classically associated with depression. However, robust evidence is lacking regarding general clinic populations. Our aim was to evaluate the association between AA and major depressive disorder (MDD) in geriatric outpatients from a middle-income country.

METHODS

We conducted a cross-sectional analysis of a cohort study. MDD diagnosis was assessed with a psychiatric interview (SCID-5-CV) according to DSM-5 criteria. Depressive symptomatology was assessed by a 15-items Geriatric Depression Scale (GDS) and the PHQ-9 questionnaire. Appetite was measured with the Simple Nutrition Appetite Questionnaire (SNAQ), whereas AA was defined as a SNAQ score ≤13 points). Linear and logistic regression analysis adjusted for potential confounders were applied to assess the association between depressive symptomatology, MDD and AA.

RESULTS

Of the total 339 participants, MDD was present in 65. AA was more frequent in patients with MDD compared to non-depressed patients (30.7 versus 7.7%; p<0.001). The SNAQ score was lower in depressed patients (14.5 vs. 16.6, p<0.001). Adjusted for confounding, linear and logistic regression showed a significant association between the GDS score, PHQ-9 score and MDD with the SNAQ score (p<0.001) and cut-off representing AA (p<0.001), respectively. Moreover, MDD and AA interacted significantly with their association with weight loss (p<0.001).

CONCLUSIONS

Depression scales (even without somatic complaints) and MDD were associated with AA in geriatric outpatients. AA is associated with weight loss in MDD. Prospective studies should expand these findings.

Preliminary evidence of acylated ghrelin association with depression severity in postmenopausal women

We have previously shown increased depression and anxiety scores in postmenopausal overweight women, when compared to overweight premenopausal women. The mechanisms responsible for these alterations are not understood. Although ghrelin involvement in mood modulation has been suggested, its role is still ambiguous and has not been evaluated in postmenopause. Here we investigated the association of ghrelin with depression and anxiety symptoms in postmenopausal women. Fifty-five postmenopausal women with depression symptoms, who were not in use of hormones or antidepressants, were included in the study. Depression symptoms were evaluated by Beck's Depression Inventory (BDI) and Patient Health Questionnaire-9 (PHQ-9) and anxiety symptoms were evaluated by Beck's Anxiety Inventory (BAI). Women were allocated into three groups, according to BDI classification of mild, moderate, or severe depression symptoms. Anthropometric, biochemical and hormonal parameters were analyzed. Total and acylated ghrelin levels were higher in the severe depression than in the mild depression group. Multivariate regression analyses showed positive associations of BDI scores with acylated ghrelin and BMI, and of PHQ-9 scores with acylated ghrelin and homeostasis model assessment of insulin resistance (HOMA-IR). BAI scores associated positively with waist-to-hip ratio. To the best of our knowledge, this is the first demonstration of an association between acylated ghrelin and the severity of depression symptoms in postmenopausal women. This association may reflect either a physiological response aimed at fighting against depression symptoms or a causal factor of this mental disorder.

Elevated peripheral inflammation is associated with attenuated striatal reward anticipation in major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is the leading cause of years lived with disability worldwide, and up to 40% of individuals with MDD do not respond to current treatments. Studies suggest that peripheral inflammation plays an important role in the striatal mesolimbic dopamine pathway and corticostriatal reward circuitry in MDD. Although MDD patients show blunted striatal responses to reward, the link between degree of inflammation and attenuation of reward processing is unclear. We investigated whether MDD patients with elevated peripheral inflammation exhibit attenuated reward responses to enhance our understanding of MDD pathophysiology and develop more effective treatments for current non-responders.

METHODS

MDD subjects varying on serum C-reactive protein (CRP) concentrations (MDD-High CRP, >3 mg/L, n = 44; MDD-Low CRP, <3 mg/L, n = 44) and healthy comparisons (HC, n = 44) completed a monetary incentive delay (MID) task and provided blood samples to measure inflammation-related markers. MDD-High and MDD-Low were propensity score-matched on age, sex, body mass index (BMI), smoking status, exercise and MID task head motion. Percent change in blood oxygen level-dependent (BOLD) signal during anticipation of wins and losses was extracted from bilateral nucleus accumbens, dorsal caudate and dorsolateral putamen regions of interest (ROIs). A linear mixed-effects model was used to test group (MDD-High, MDD-Low and HC), condition (large-win, small-win and no win), and their interaction for these ROIs as well as whole-brain voxelwise data. Analyses also tested group differences in inflammatory mediators. Correlations were used to explore the relationship between inflammatory mediators and brain regions showing differences between MDD-High and MDD-Low.

RESULTS

MDD-High exhibited: (a) lower BOLD signal change in dorsal caudate, thalamus, left insula and left precuneus during anticipation of small wins than MDD-Low; and (b) higher serum soluble intercellular adhesion molecule 1 (sICAM-1) and interleukin 6 (IL-6) concentrations than MDD-Low and HC. MDD as a whole, regardless of CRP-based inflammation, exhibited: (a) lower precuneus BOLD signal change to large wins than HC; and (b) higher Interleukin 1 receptor antagonist (IL-1ra), macrophage-derived chemokine (MDC) and macrophage inflammatory protein-1 alpha (MIP-1α) concentrations than HC. Higher serum sICAM-1 concentrations were associated with lower caudate BOLD signal change to small wins only within the MDD-High group.

CONCLUSION

Within MDD patients, high inflammation (CRP, sICAM-1) was linked to reduced striatal activation recruited to discriminate intermediate reward magnitudes. These findings support an association between levels of peripheral inflammation and the degree of reward-related activation in individuals with MDD.

REGISTRATION OF CLINICAL TRIALS

The ClinicalTrials.gov identifier for the clinical protocol associated with data published in this current paper is NCT02450240, "Latent Structure of Multi-level Assessments and Predictors of Outcomes in Psychiatric Disorders."

Body Mass Index Is Significantly Associated With Disease Severity in Spinocerebellar Ataxia Type 2 Patients

BACKGROUND

Spinocerebellar ataxia type 2 is a progressive neurodegenerative disorder due to an unstable expansion of a CAG repeat in the ATXN2 gene. Although weight loss has been associated with disease progression in several neurodegenerative conditions, it has been barely assessed in patients with spinocerebellar ataxia type 2.

OBJECTIVE

The objective of this study was to test whether body mass index is altered in patients with spinocerebellar ataxia type 2 with varying expansion sizes from early to late disease stages.

METHODS

A cross-sectional case-control study was performed, which included 222 clinically and molecularly diagnosed patients and 214 sex- and age-matched healthy individuals. ATXN2 genotypes and sex were considered as risk factors. Clinical outcomes included the body mass index, age at onset, disease duration, Scale for the Assessment and Rating of Ataxia score, disease stage, dysphagia, and progression rate. Multiple linear regression models were generated.

RESULTS

Body mass index was significantly decreased in male patients, but not in female patients, relative to control subjects. In addition to sex, body mass index was significantly associated with age at onset and progression rate. Conversely, body mass index, along with repeat length in ATXN2 expanded alleles and disease duration, was associated with Scale for the Assessment and Rating of Ataxia score. In addition, body mass index, along with the age at onset and the repeat length in ATXN2 normal and expanded alleles, has a significant influence on progression rate.

CONCLUSIONS

Body mass index might be a useful biomarker of disease severity, particularly in male patients with spinocerebellar ataxia type 2 in the context of nutritional interventions or clinical trials assessing the efficacy of promising new drugs. © 2021 International Parkinson and Movement Disorder Society.

Dissecting the Association Between Inflammation, Metabolic Dysregulation, and Specific Depressive Symptoms: A Genetic Correlation and 2-Sample Mendelian Randomization Study

IMPORTANCE

Observational studies highlight associations of C-reactive protein (CRP), a general marker of inflammation, and interleukin 6 (IL-6), a cytokine-stimulating CRP production, with individual depressive symptoms. However, it is unclear whether inflammatory activity is associated with individual depressive symptoms and to what extent metabolic dysregulation underlies the reported associations.

OBJECTIVE

To explore the genetic overlap and associations between inflammatory activity, metabolic dysregulation, and individual depressive symptoms.

GWAS DATA SOURCES

Genome-wide association study (GWAS) summary data of European individuals, including the following: CRP levels (204 402 individuals); 9 individual depressive symptoms (3 of which did not differentiate between underlying diametrically opposite symptoms [eg, insomnia and hypersomnia]) as measured with the Patient Health Questionnaire 9 (up to 117 907 individuals); summary statistics for major depression, including and excluding UK Biobank participants, resulting in sample sizes of 500 199 and up to 230 214 individuals, respectively; insomnia (up to 386 533 individuals); body mass index (BMI) (up to 322 154 individuals); and height (up to 253 280 individuals).

DESIGN

In this genetic correlation and 2-sample mendelian randomization (MR) study, linkage disequilibrium score (LDSC) regression was applied to infer single-nucleotide variant-based heritability and genetic correlation estimates. Two-sample MR tested potential causal associations of genetic variants associated with CRP levels, IL-6 signaling, and BMI with depressive symptoms. The study dates were November 2019 to April 2020.

RESULTS

Based on large GWAS data sources, genetic correlation analyses revealed consistent false discovery rate (FDR)-controlled associations (genetic correlation range, 0.152-0.362; FDR P = .006 to P < .001) between CRP levels and depressive symptoms that were similar in size to genetic correlations of BMI with depressive symptoms. Two-sample MR analyses suggested that genetic upregulation of IL-6 signaling was associated with suicidality (estimate [SE], 0.035 [0.010]; FDR plus Bonferroni correction P = .01), a finding that remained stable across statistical models and sensitivity analyses using alternative instrument selection strategies. Mendelian randomization analyses did not consistently show associations of higher CRP levels or IL-6 signaling with other depressive symptoms, but higher BMI was associated with anhedonia, tiredness, changes in appetite, and feelings of inadequacy.

CONCLUSIONS AND RELEVANCE

This study reports coheritability between CRP levels and individual depressive symptoms, which may result from the potentially causal association of metabolic dysregulation with anhedonia, tiredness, changes in appetite, and feelings of inadequacy. The study also found that IL-6 signaling is associated with suicidality. These findings may have clinical implications, highlighting the potential of anti-inflammatory approaches, especially IL-6 blockade, as a putative strategy for suicide prevention.

Associations between depressive symptom profiles and immunometabolic characteristics in individuals with depression and their siblings

OBJECTIVES

The present study examined associations between immunometabolic characteristics (IMCs) and depressive symptom profiles (DSPs) in probands with lifetime diagnoses of depression and/or anxiety disorders and their siblings.

METHODS

Data were from the Netherlands Study of Depression and Anxiety, comprising 256 probands with lifetime diagnoses of depression and/or anxiety and their 380 siblings. Measured IMCs included blood pressure, waist circumference, and levels of glucose, triglycerides, HDL cholesterol, CRP, TNF-α and IL-6. DSPs included mood, cognitive, somatic and atypical-like profiles. We cross-sectionally examined whether DSPs were associated with IMCs within probands and within siblings, and whether DSPs were associated with IMCs between probands and siblings.

RESULTS

Within probands and within siblings, higher BMI and waist circumference were associated with higher somatic and atypical-like profiles. Other IMCs (IL-6, glucose and HDL cholesterol) were significantly related to DSPs either within probands or within siblings. DSPs and IMCs were not associated between probands and siblings.

CONCLUSIONS

The results suggest that there is a familial component for each trait, but no common familial factors for the association between DSPs and IMCs. Alternative mechanisms, such as direct causal effects or non-shared environmental risk factors, may better fit these results.

How handling extreme C-reactive protein (CRP) values and regularization influences CRP and depression criteria associations in network analyses

Increasingly, it has been recognized that analysis at the symptom, rather than diagnostic, level will drive progress in the field of immunopsychiatry. Network analysis offers a useful tool in this pursuit with the ability to identify associations between immune markers and individual symptoms, independent of all other variables modeled. However, investigation into how methodological decisions (i.e., including vs. excluding participants with C-reactive protein (CRP) >10 mg/L, regularized vs. nonregularized networks) influence results is necessary to establish best practices for the use of network analysis in immunopsychiatry. In a sample of 3,464 adult participants from the 2015-2016 National Health and Nutrition Examination Survey dataset, this study found consistent support for associations between CRP and fatigue and changes in appetite and some support for additional CRP-criterion associations. Methodologically, results consistently demonstrated that including individuals with CRP >10 mg/L and estimating nonregularized networks provided better estimates of these associations. Thus, we recommend considering the use of nonregularized networks in immunopsychiatry and inclusion of cases with CRP values >10 mg/L when testing the association between CRP and depression criteria, unless contraindicated by the research question being tested. Additionally, results most consistently suggest that CRP is uniquely related to fatigue and changes in appetite, supporting their inclusion in an immunometabolic phenotype of depression. Finally, these associations suggest that fatigue and changes in appetite might be particularly receptive to anti-inflammatory treatments. However, future research with more nuanced measures is necessary to parse out whether appetite increases or decreases drive this association. Further, longitudinal research is an important next step to test how these relationships manifest over time.

The Good, the Bad and the Unknown Aspects of Ghrelin in Stress Coping and Stress-Related Psychiatric Disorders

Ghrelin is a peptide hormone released by specialized X/A cells in the stomach and activated by acylation. Following its secretion, it binds to ghrelin receptors in the periphery to regulate energy balance, but it also acts on the central nervous system where it induces a potent orexigenic effect. Several types of stressors have been shown to stimulate ghrelin release in rodents, including nutritional stressors like food deprivation, but also physical and psychological stressors such as foot shocks, social defeat, forced immobilization or chronic unpredictable mild stress. The mechanism through which these stressors drive ghrelin release from the stomach lining remains unknown and, to date, the resulting consequences of ghrelin release for stress coping remain poorly understood. Indeed, ghrelin has been proposed to act as a stress hormone that reduces fear, anxiety- and depression-like behaviors in rodents but some studies suggest that ghrelin may - in contrast - promote such behaviors. In this review, we aim to provide a comprehensive overview of the literature on the role of the ghrelin system in stress coping. We discuss whether ghrelin release is more than a byproduct of disrupted energy homeostasis following stress exposure. Furthermore, we explore the notion that ghrelin receptor signaling in the brain may have effects independent of circulating ghrelin and in what way this might influence stress coping in rodents. Finally, we examine how the ghrelin system could be utilized as a therapeutic avenue in stress-related psychiatric disorders (with a focus on anxiety- and trauma-related disorders), for example to develop novel biomarkers for a better diagnosis or new interventions to tackle relapse or treatment resistance in patients.

Ghrelin as a Stress Hormone: Implications for Psychiatric Illness

The stress response is an adaptive means of maintaining physiological homeostasis in the face of changing environmental conditions. However, protracted recruitment of stress systems can precipitate wear and tear on the body and may lead to many forms of disease. The mechanisms underlying the connection between chronic stress and disease are not fully understood and are likely multifactorial. In this review, we evaluate the possibility that the hormone ghrelin may contribute to the pathophysiology that follows chronic stress. Since ghrelin was discovered as a pro-hunger hormone, many additional roles for it have been identified, including in learning, memory, reward, and stress. We describe the beneficial effects that ghrelin exerts in healthy mammals and discuss that prolonged exposure to ghrelin has been linked to maladaptive responses and behaviors in the realm of psychiatric disease. In addition, we consider whether chronic stress-associated altered ghrelin signaling may enhance susceptibility to posttraumatic stress disorder and comorbid conditions such as major depressive disorder and alcohol use disorder. Finally, we explore the possibility that ghrelin-based therapeutics could eventually form the basis of a treatment strategy for illnesses that are linked to chronic stress and potentially also ghrelin dysregulation, and we identify critical avenues for future research in this regard.

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.

The potential anti-depressant properties of dexmedetomidine infusion: a review of mechanistic, preclinical, and clinical evidence

Major depressive disorder (MDD) is a highly prevalent and disabling condition for which the currently available treatments are not fully effective. Existing unmet needs include rapid onset of action and optimal management of concurrent agitation. Dexmedetomidine (DEX) is a selective and potent α2-adrenergic receptor (α2-AR) agonist, with unique pharmacokinetic and pharmacodynamic properties. In this review, we discuss pre-clinical and clinical studies which focused on DEX in the context of its putative antidepressant effects for the management of MDD. Preliminary data support DEX as an antidepressant with fast onset of action, which would be especially helpful for patients experiencing treatment resistant depression, and agitation. We further explore the mechanistic and clinical implications of considering DEX as a putative antidepressant agent, and the next steps to explore the efficacy of low dose DEX infusion among patients with treatment resistant depression.

Structural and biochemical imaging reveals systemic LPS-induced changes in the rat brain

Despite mounting evidence for the role of inflammation in Major Depressive Disorder (MDD), in vivo preclinical investigations of inflammation-induced negative affect using whole brain imaging modalities are scarce, precluding a valid model within which to evaluate pharmacological interventions. Here we used an E. coli lipopolysaccharide (LPS)-based model of inflammation-induced depressive signs in rats to explore brain changes using multimodal neuroimaging methods. During the acute phase of the LPS response (2 h post injection), prior to the emergence of a task-quantifiable depressive phenotype, striatal glutamine levels and splenial, retrosplenial, and peri-callosal hippocampal cortex volumes were greater than at baseline. LPS-induced depressive behaviors observed at 24 h, however, occurred concurrently with lower than control levels of striatal glutamine and a reversibility of volume expansion (i.e., shrinkage of splenial, retrosplenial, and peri-callosal hippocampal cortex to baseline volumes). In both striatum and hippocampus at 24 h, mRNA expression in LPS relative to control animals demonstrated alterations in enzymes and transporters regulating glutamine homeostasis. Collectively, the observed behavioral, in vivo structural and metabolic, and mRNA expression alterations suggest a critical role for astrocytic regulation of inflammation-induced depressive behaviors.

Inflammation as a treatment target in mood disorders: review

BACKGROUND

Mood disorders, i.e. major depressive disorder (MDD) and bipolar disorders, are leading sources of disability worldwide. Currently available treatments do not yield remission in approximately a third of patients with a mood disorder. This is in part because these treatments do not target a specific core pathology underlying these heterogeneous disorders. In recent years, abnormal inflammatory processes have been identified as putative pathophysiological mechanisms and treatment targets in mood disorders, particularly among individuals with treatment-resistant conditions.

AIMS

In this selective review, we aimed to summarise recent advances in the field of immunopsychiatry, including emerging pathophysiological models and findings from treatment ttrials of immunomodulatory agents for both MDD and bipolar disorders.

METHOD

We performed a literature review by searching Medline for clinical trials of immunomodulating agents as monotherapy or adjunctive treatments in MDD and bipolar disorders. Included studies are randomised controlled trials (RCTs), cluster RCTs or cross-over trials of immunomodulating agents that had an active comparator or a placebo-arm.

RESULTS

Current evidence shows an association between inflammation and mood symptoms. However, there is conflicting evidence on whether this link is causal.

CONCLUSIONS

Future studies should focus on identifying specific neurobiological underpinnings for the putative causal association between an activated inflammatory response and mood disorders. Results of these studies are needed before further treatment trials of immunomodulatory agents can be justified.

Cardiometabolic risk in young adults with depression and evidence of inflammation: A birth cohort study

BACKGROUND

Young adults with depression and evidence of inflammation may represent a high-risk group for cardiometabolic disorders, but studies of cardiometabolic risk in this population are scarce. We aimed to examine: (1) the prevalence of low-grade inflammation in young-adults with depression; (2) cross-sectional and longitudinal associations between cardiometabolic risk factors and depression with or without evidence of inflammation.

METHOD

The ALSPAC birth cohort participants were assessed for depression and serum high-sensitivity C-Reactive Protein (CRP) levels at age 18, alongside cardiometabolic measures (fasting insulin, fasting plasma glucose, low-density lipoprotein, high-density lipoprotein, triglycerides, smoking, alcohol intake) at age 18 years, and body mass index at ages 9, 13 and 18 years. Low-grade inflammation was defined as CRP>3 mg/L. Multinomial regression was used to examine associations of cardiometabolic markers with depression cases with and without evidence of inflammation. Sensitivity analyses were conducted to examine for interactions between depression, inflammation and cardiometabolic traits.

RESULTS

Out of 2932 participants, 215 met ICD-10 criteria for depressive episode at age 18 years; 23 (10.7 %) had CRP>3 mg/L and 57 (26.5 %) had CRP 1-3 mg/L. Depressive episode with raised CRP (>3 mg/L) was associated with higher triglycerides (adjusted OR = 2.09; 95 % C.I., 1.35-3.24), higher BMI (adjusted OR = 1.13; 95 % C.I., 1.05-1.22) and insulin insensitivity (adjusted OR = 1.12; 95 % C.I., 1.01-1.26), and longitudinally with higher BMI at ages 9 (adjusted OR = 1.27; 95 % C.I., 1.10-1.48) and 13 (adjusted OR = 1.23; 95 % C.I., 1.09-1.38). There was evidence for interaction between BMI and CRP for the risk of depression at age 18 (adjusted OR for the interaction term = 1.56; 95 % C.I. 0.98-2.02) and between CRP and depressive symptoms for the risk of increased BMI at age 18 (adjusted β for the interaction term = 0.05; 95 % C.I. 0.00-0.12).

CONCLUSIONS

A notable proportion of young adults with depression have evidence of inflammation. These individuals are at increased risk of cardiometabolic disorders. Management of cardiometabolic risk in depressed individuals with evidence of inflammation should form part of routine clinical practice.

Prognosis and Improved Outcomes in Major Depression: A Review

(Reprinted from Transl Psychiatry. 2019 Apr 3; 9(1):127. Open access; is licensed under a Creative Commons Attribution 4.0 International License).

Neurovegetative symptom subtypes in young people with major depressive disorder and their structural brain correlates

Depression is a leading cause of burden of disease among young people. Current treatments are not uniformly effective, in part due to the heterogeneous nature of major depressive disorder (MDD). Refining MDD into more homogeneous subtypes is an important step towards identifying underlying pathophysiological mechanisms and improving treatment of young people. In adults, symptom-based subtypes of depression identified using data-driven methods mainly differed in patterns of neurovegetative symptoms (sleep and appetite/weight). These subtypes have been associated with differential biological mechanisms, including immuno-metabolic markers, genetics and brain alterations (mainly in the ventral striatum, medial orbitofrontal cortex, insular cortex, anterior cingulate cortex amygdala and hippocampus). K-means clustering was applied to individual depressive symptoms from the Quick Inventory of Depressive Symptoms (QIDS) in 275 young people (15-25 years old) with MDD to identify symptom-based subtypes, and in 244 young people from an independent dataset (a subsample of the STAR*D dataset). Cortical surface area and thickness and subcortical volume were compared between the subtypes and 100 healthy controls using structural MRI. Three subtypes were identified in the discovery dataset and replicated in the independent dataset; severe depression with increased appetite, severe depression with decreased appetite and severe insomnia, and moderate depression. The severe increased appetite subtype showed lower surface area in the anterior insula compared to both healthy controls. Our findings in young people replicate the previously identified symptom-based depression subtypes in adults. The structural alterations of the anterior insular cortex add to the existing evidence of different pathophysiological mechanisms involved in this subtype.

Stability and transition of depression subtypes in late life

BACKGROUND

The heterogeneity of late-life depression hampers diagnosis and treatment. Data-driven methods have identified several subtypes of depression in older persons, but the longitudinal stability of these subtypes remains unknown.

METHODS

In total 111 older persons with a major depressive disorder both at baseline and 2-year follow-up from the Netherlands Study of Depression in Older persons (NESDO) were included. Latent class analysis was performed to identify subtypes of depression at baseline and at 2-year follow-up, and latent transition analysis was used to examine the stability of these subtypes over time. Transition rates between subtypes and characteristics of groups were examined.

RESULTS

Two subtypes were identified in both baseline (T0) and follow-up data (T1), including a 'melancholic' subtype (prevalence 80.2% (T0) and 62.2% (T1)), and an 'atypical' subtype (prevalence 19.8% (T0) and 37.8% (T1)). The melancholic subtype was characterized by decreased appetite and weight and had a stability of 0.86. The atypical subtype was characterized by increased appetite and weight and had a stability of 0.93, although the discriminating power of different symptoms had decreased at T1. Mean age and education differed significantly between stable and transitioning subgroups, other characteristics did not differ between subgroups.

LIMITATIONS

Limited sample size might have hampered the analyses.

CONCLUSIONS

Subtypes of late-life depression are relatively stable, but symptoms of depression (like weight loss) seem to blur with symptoms of (patho)physiological aging. This underlines the clinical relevance of depression subtyping, but also the importance of further research into subtypes and the influence of aging.

Association of poorer dietary quality and higher dietary inflammation with greater symptom severity in depressed individuals with appetite loss

BACKGROUND

Major depressive disorder (MDD) is the leading cause of years lived with disability; however, little is known about its etiology to inform treatment. For a subset of MDD patients, appetite change and/or bodily inflammation may play a role in exacerbating symptoms. The goal of this study is to examine whether, relative to healthy comparisons (HC), MDD individuals with increased versus decreased appetite symptoms show a differential relationship between diet quality and inflammation.

METHODS

Unmedicated current MDD (n = 61) varying in appetite change (decrease (MDD-DE): n = 39; increase (MDD-IN): n = 22) and HC (n = 42) completed 24-hour dietary recall and state depression/anxiety measures. Healthy eating and dietary inflammatory indices were calculated from dietary reports. Blood samples measured five inflammation-related biomarkers. Analyses investigated between- and within-group differences in the Healthy Eating Index (HEI), the Dietary Inflammatory Index (DII), inflammation-related blood biomarkers, and symptom severity.

RESULTS

While both MDD-DE and MDD-IN exhibited lower HEI scores than HC, only MDD-IN showed higher plasma interleukin-1 receptor antagonist (IL-1RA) and interleukin-6 (IL-6) levels than HC. In contrast, MDD-DE exhibited higher DII scores than MDD-IN and HC. Within MDD-DE, greater symptom severity was associated with lower HEI and higher DII.

LIMITATIONS

Modest sample sizes and the cross-sectional study design limited power to detect within-MDD effects.

CONCLUSIONS

Although MDD, regardless of appetite change, is linked to poorer dietary quality, depression severity was related to dietary characteristics only in subjects who reported appetite loss. Thus, increasing the quality of dietary intake could be a treatment target for some individuals with depression.

Appetite change profiles in depression exhibit differential relationships between systemic inflammation and activity in reward and interoceptive neurocircuitry

Appetite change is a defining feature of major depressive disorder (MDD), yet little neuroscientific evidence exists to explain why some individuals experience increased appetite when they become depressed while others experience decreased appetite. Previous research suggests depression-related appetite changes can be indicative of underlying neural and inflammatory differences among MDD subtypes. The present study explores the relationship between systemic inflammation and brain circuitry supporting food hedonics for individuals with MDD. Sixty-four participants (31 current, unmedicated MDD and 33 healthy controls [HC]) provided blood samples for analysis of an inflammatory marker, C-reactive protein (CRP), and completed a functional magnetic resonance imaging (fMRI) scan in which they rated the perceived pleasantness of various food stimuli. Random-effects multivariate modeling was used to explore group differences in the relationship between CRP and the coupling between brain activity and inferred food pleasantness (i.e., strength of the relationship between activity and pleasantness ratings). Results revealed that for MDD with increased appetite, higher CRP in blood related to greater coupling between orbitofrontal cortex and anterior insula activity and inferred food pleasantness. Compared to HC, all MDD exhibited a stronger positive association between CRP and coupling between activity in striatum and inferred food pleasantness. These findings suggest that for individuals with MDD, systemic low-grade inflammation is associated with differences in reward and interoceptive-related neural circuitry when making hedonic inferences about food stimuli. In sum, altered immunologic states may affect appetite and inferences about food reward in individuals with MDD and provide evidence for physiological subtypes of MDD.

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

Major depression and enhanced molecular senescence abnormalities in young and middle-aged adults

Recent evidence suggests a significant overlap in biological changes between major depression and aging across the lifespan. We aim to evaluate the impact of a major depressive episode on the Senescence-Associated Secretory Phenotype (SASP) index, a dynamic secretory molecular pattern indicative of cellular senescence. We also tested the potential moderators of the association between major depression and the SASP index. We included 1165 young and middle-aged adults (527 with a current major depressive episode (cMDE) and 638 with no lifetime history of depression) from a community-based cohort from the Netherlands. We calculated the SASP index based on a previously developed composite index involving 19 biomarkers. cMDE had higher SASP index values (t₍₁₁₆₃₎ = 2.93, p = 0.003) compared to controls in the univariate analysis. After controlling for sociodemographic and somatic health covariates, there was no significant association between cMDE and SASP index (F_(1,1158) = 1.09, p = 0.29). Those with the most severe depressive episodes had significantly higher SASP indices compared to those with mild-to-moderate cMDE and controls (F_(2,1162) = 6.73, p = 0.001). We found a significant interaction between cMDE and overweight (F_(1,1164) = 5.1, p = 0.028): those with comorbid cMDE and overweight had the highest SASP index. Our study demonstrated a complex interaction between cMDE and medical morbidity, especially overweight, on the SASP index, suggesting that their coexistence aggravate age-related biological processes. Moreover, higher SASP index can be a biomarker for more severe depressive episodes.

Involvement of inflammatory gene expression pathways in depressed patients with hyperphagia

The pathophysiology of major depressive disorder (MDD) is highly heterogeneous. Previous evidence at the DNA level as well as on the serum protein level suggests that the role of inflammation in MDD pathology is stronger in patients with hyperphagia during an active episode. Which inflammatory pathways differ in MDD patients with hyperphagia inflammatory pathways in terms of gene expression is unknown. We analyzed whole-blood gene expression profiles of 881 current MDD cases and 331 controls from the Netherlands Study of Depression and Anxiety (NESDA). The MDD patients were stratified according to patients with hyperphagia (characterized by increased appetite and/or weight, N = 246) or hypophagia (characterized by decreased appetite and/or weight, N = 342). Using results of differential gene expression analysis between controls and the MDD subgroups, enrichment of curated inflammatory pathways was estimated. The majority of the pathways were significantly (FDR < 0.1) enriched in the expression profiles of MDD cases with hyperphagia, including top pathways related to factors responsible for the onset of inflammatory response ('caspase', 'GATA3', 'NFAT', and 'inflammasomes' pathways). Only two pathways ('adaptive immune system' and 'IL-8- and CXCR2-mediated signaling') were enriched in the MDD with hypophagia subgroup, these were also enriched in the total current MDD group and the group with hyperphagia. This confirms the importance of inflammation in MDD pathology of patients with hyperphagia, and suggests that distinguishing more uniform MDD phenotypes can help in finding their pathophysiological basis.

Glucocorticoid Resistance: Is It a Requisite for Increased Cytokine Production in Depression? A Systematic Review and Meta-Analysis

Background: Glucocorticoid resistance-reduced function of the glucocorticoid receptor (GR)-is seen in many depressed patients. It is argued that this resistance to glucocorticoids leads to failure of normal feedback regulation on the immune system. High levels of pro-inflammatory cytokines result. Purpose: We sought to identify evidence supporting or refuting a link between glucocorticoid resistance and immune dysregulation in depression and to summarize retrieved evidence in aggregate form. Methods: We systematically reviewed and meta-analyzed studies that examined cytokine levels in depressed patients compared with controls and that also reported a measure of glucocorticoid resistance. These measures included plasma cortisol, the dexamethasone suppression test (DST), GR expression levels, and the results of in vitro assays of GR function. We conducted four separate meta-analyses to test for moderating effects of glucocorticoid resistance on cytokine production in depression. Results: After sub-grouping 32 studies by the ratio of cortisol levels in patients compared with controls, we observed a trend for increasing glucocorticoid resistance (i.e., the most hypercortisolemic patients) to be associated with increased production of interleukin (IL)-6 [d = 0.94; 95% CI (0.29, 1.59)] and tumour necrosis factor (TNF)-α [d = 0.46; 95% CI (0.12, 0.79)]. We stratified nine studies that reported DST results by relative glucocorticoid resistance between patients and controls, identifying a trend for higher glucocorticoid resistance in patients, compared with controls, to be associated with higher cytokine production in patients (170 patients and 187 controls). This was particularly evident when studies were sub-grouped by source of cytokine-plasma (d = 1.04; 95% CI, 0.57-1.50) versus in vitro (d = 0.24; 95% CI, -0.20 to 0.67). Stratifying the four studies (147 patients and 118 controls) that used in vitro assays of GR function or GR expression to quantify glucocorticoid resistance revealed variable contributions to cytokine production in patients compared with controls (overall effect size: d = 1.35; 95% CI 0.53-2.18). Combining our analyses of studies that reported DST results with those that used in vitro assays of GR function or GR expression to quantify glucocorticoid resistance (302 patients and 277 controls), we noted that although depressed patients produced more cytokines than controls (d = 1.02; 95% CI, 0.55-1.49), there was no evident positive correlation between glucocorticoid resistance and inflammation. Conclusions: Our work provides some support for a model conceptualizing glucocorticoid resistance as a requisite for increased inflammation in depression. The limited number of studies identified highlights the need for purpose-designed investigations that directly examine the relationship between glucocorticoid resistance and cytokine production in depression.

CA, Kasper S. Prognosis and improved outcomes in major depression: a review

Treatment outcomes for major depressive disorder (MDD) need to be improved. Presently, no clinically relevant tools have been established for stratifying subgroups or predicting outcomes. This literature review sought to investigate factors closely linked to outcome and summarize existing and novel strategies for improvement. The results show that early recognition and treatment are crucial, as duration of untreated depression correlates with worse outcomes. Early improvement is associated with response and remission, while comorbidities prolong course of illness. Potential biomarkers have been explored, including hippocampal volumes, neuronal activity of the anterior cingulate cortex, and levels of brain-derived neurotrophic factor (BDNF) and central and peripheral inflammatory markers (e.g., translocator protein (TSPO), interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor alpha (TNFα)). However, their integration into routine clinical care has not yet been fully elucidated, and more research is needed in this regard. Genetic findings suggest that testing for CYP450 isoenzyme activity may improve treatment outcomes. Strategies such as managing risk factors, improving clinical trial methodology, and designing structured step-by-step treatments are also beneficial. Finally, drawing on existing guidelines, we outline a sequential treatment optimization paradigm for selecting first-, second-, and third-line treatments for acute and chronically ill patients. Well-established treatments such as electroconvulsive therapy (ECT) are clinically relevant for treatment-resistant populations, and novel transcranial stimulation methods such as theta-burst stimulation (TBS) and magnetic seizure therapy (MST) have shown promising results. Novel rapid-acting antidepressants, such as ketamine, may also constitute a paradigm shift in treatment optimization for MDD.

Metabolic and Microbiota Measures as Peripheral Biomarkers in Major Depressive Disorder

Advances in understanding the role of the microbiome in physical and mental health are at the forefront of medical research and hold potential to have a direct impact on precision medicine approaches. In the past 7 years, we have studied the role of microbiota-brain communication on behavior in mouse models using germ-free mice, mice exposed to antibiotics, and healthy specific pathogen free mice. Through our work and that of others, we have seen an amazing increase in our knowledge of how bacteria signal to the brain and the implications this has for psychiatry. Gut microbiota composition and function are influenced both by genetics, age, sex, diet, life experiences, and many other factors of psychiatric and bodily disorders and thus may act as potential biomarkers of the gut-brain axis that could be used in psychiatry and co-morbid conditions. There is a particular need in major depressive disorder and other mental illness to identify biomarkers that can stratify patients into more homogeneous groups to provide better treatment and for development of new therapeutic approaches. Peripheral outcome measures of host-microbe bidirectional communication have significant translational value as biomarkers. Enabling stratification of clinical populations, based on individual biological differences, to predict treatment response to pharmacological and non-pharmacological interventions. Here we consider the links between co-morbid metabolic syndrome and depression, focusing on biomarkers including leptin and ghrelin in combination with assessing gut microbiota composition, as a potential tool to help identify individual differences in depressed population.