Fibroblast growth factor 21 (FGF21) is increased in MDD and interacts with body mass index (BMI) to affect depression trajectory.

Fibroblast growth factor 21 (FGF21) is a key regulator of metabolic function and nutrient preference. It also affects biological pathways associated with major depressive disorder (MDD), including corticotrophin-releasing hormone (CRH), leptin, and sympathetic activity. Lower levels of cerebrospinal fluid FGF21 have been associated with higher Beck Depression Inventory scores. FGF21 was examined as a metabolic marker that could be associated with MDD and evaluated as a biomarker of antidepressant treatment response in a large, randomized placebo-controlled trial in chronic, early-onset MDD participants. FGF21 levels at baseline and during treatment were determined for participants in the Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care (EMBARC) study. FGF21 was analyzed by ELISA in individuals with chronic, early-onset MDD (first major depressive episode before 30 years) compared to healthy control participants. Participants with MDD had higher levels of FGF21 compared to healthy controls (HCs), even after controlling for baseline age, sex, race, Hispanic ethnicity, BMI, and site (ß-coefficient = 1.20, p < 0.0001, Cohen's d = 0.60). FGF21 did not change over time nor differ between treatment groups. Interestingly though, those with normal BMI and lower FGF21 levels showed a reduction in depression severity over time compared to all other groups. In conclusion, depression is associated with higher levels of FGF21 compared to healthy controls and those with lower levels of FGF21 (25th percentile of the sample) in the context of normal-weight BMI seem to have improved depression severity over time.

Comparison of inflammatory markers as moderators of depression outcomes: A CO-MED study.

BACKGROUND: Prior work suggests some individual immunomarkers may be useful moderators of treatment response between antidepressant medications. The relative moderating effect of individual immunomarkers remains unclear. It is also unknown whether combinations of immunomarkers have a superior moderating effect compared to any individual immunomarker. METHODS: Baseline immunomarker levels were assayed using multiplex from a subset of participants in the CO-MED trial (n = 143). Individual and combinations of 19 immunomarkers were modeled as moderators between the three treatment arms (escitalopram monotherapy, escitalopram-bupropion and venlafaxine-mirtazapine) across a variety of depression outcomes. RESULTS: Only IL-13 demonstrated a consistent moderating effect across all depression outcome measures. High IL-13 (>20 pg/ml) was associated with higher remission rates to bupropion-escitalopram (67%) versus escitalopram (24%) whereas low IL-13 was associated higher remission rates to escitalopram (59%) versus bupropion-escitalopram (38%). A similar, but weaker moderating effect was observed with venlafaxine-mirtazapine versus escitalopram. The addition of multiple immunomarkers did not consistently improve predictive modeling. LIMITATIONS: This is a secondary analysis of a single clinical trial with a relatively small sample size per treatment arm. The testing of specific individual and combinations of biomarkers was data-driven. CONCLUSIONS: Among 19 immunomarkers, Il-13 was the best single moderator of treatment outcome. Combinations of immunomarkers were not meaningfully superior to Il-13.

Impact of the COVID-19 pandemic on adults with current and prior depression: initial findings from the longitudinal Texas RAD study.

BACKGROUND: Emerging work has suggested worsening mental health in the general population during the COVID-19 pandemic, but there is minimal data on individuals with a prior history of depression. METHODS: Data regarding depression, anxiety and quality of life in adult participants with a history of a depressive disorder (n = 308) were collected before and during the COVID-19 pandemic. Mixed effects regression models were fit for these outcomes over the period May - August 2020, controlling for pre-pandemic depressive groups (none, mild, moderate-to-severe), demographic characteristics, and early COVID-19 related experiences (such as disruptions in routines, mental health treatment, and social supports). RESULTS: In pre-to-early pandemic comparisons, the 3 pre-pandemic depressive categories varied significantly in anxiety (Fdf=2,197 = 7.93, p < 0.0005) and psychological QOL (Fdf=2,196 = 8.57, p = 0.0003). The mildly depressed group (Fdf=1,201 = 6.01, p = 0.02) and moderate-to-severely depressed group (Fdf=1,201 = 38.51, p < 0.0001) had a significant reduction in anxiety. There were no changes among the groups in any outcome from May to August 2020. However, early impact on mental health care access and disruption in routines predicted worse outcomes during this time. LIMITATIONS: Follow-up data were self-reported. Furthermore, the duration was a relatively short span into the pandemic. CONCLUSIONS: Symptoms of depression, anxiety, and quality of life were generally stable from 2019 throughout August 2020 in adults with a history of depression. Disruption in mental health care access and routines in May 2020 predicted worse symptom outcomes through August 2020.

Impact of childhood maltreatment on outcomes of antidepressant medication in chronic and/or recurrent depression.

BACKGROUND: While childhood maltreatment (CMT) is associated with higher rates of chronicity and recurrence in depression, whether CMT results in poorer outcomes with antidepressant medication remains unclear. METHODS: We performed secondary analyses with data from the large, representative, multisite trial Combining Medications to Enhance Depression Outcomes (CO-MED). CO-MED was a randomized, single-blinded, placebo-controlled study with 665 individuals (663 assessed for CMT) with chronic and/or recurrent Major Depressive Disorder (MDD). CMT was determined by a brief self-reported questionnaire assessing the four types of CMT defined by the Centers for Disease Control and Prevention: sexual abuse, emotional abuse, physical abuse, and neglect. Repeated measures and logistic regression analyses were used. RESULTS: Individuals with CMT did not have a differential improvement of depressive symptoms when compared to those without CMT (adjusted p=.203 for continuous analysis; adjusted p=.320 for remission rates). Neither type of antidepressant medication (adjusted p=.302) nor the age at which CMT occurred (adjusted p=.509) affected depressive symptom outcomes. There was no difference in functional improvement between individuals with and without CMT (adjusted p=.228). A history of CMT was associated with greater antidepressant side effects (p=.009). LIMITATIONS: This study investigated treatment-seeking individuals with chronic and/or recurrent MDD. Intensity and duration of CMT were not assessed. CONCLUSION: In a sample of treatment-seeking outpatients with chronic and/or recurrent MDD, a history of CMT was not associated with differential symptomatic or functional response to pharmacological treatment. However, those with CMT reported greater antidepressant side effect burden.

Childhood maltreatment and impact on clinical features of major depression in adults.

OBJECTIVES: This study examined: 1) the prevalence of childhood maltreatment (CMT) in individuals with chronic and/or recurrent depression, 2) the association between CMT and depressive symptoms, 3) the link between CMT and worse clinical presentation of depression, 4) the effects of accumulation of different types of CMT, and 5) the relationship between the age at CMT and depression. METHODS: We analyzed the baseline data of 663 individuals from the CO-MED study. CMT was determined by a brief self-reported questionnaire assessing sexual abuse, emotional abuse, physical abuse, and neglect. Correlational analyses were conducted. RESULTS: Half of the sample (n = 331) reported CMT. Those with CMT had higher rates of panic/phobic, cognitive and anhedonic symptoms than those without CMT. All individual types of maltreatment were associated with a poorer clinical presentation including: 1) earlier MDD onset; 2) more severe MDD, 3) more suiccidality, 4) worse quality of life, and functioning, and 5) more psychiatric comorbidities. Clinical presentation was worse in participants who reported multiple types of CMT. CONCLUSIONS: In chronic and/or recurrent depression, CMT is common, usually of multiple types and is associated with a worse clinical presentation in MDD. The combination of multiple types of CMT is associated with more impairment.

Positive and negative valence systems in major depression have distinct clinical features, response to antidepressants, and relationships with immunomarkers.

BACKGROUND: Heterogeneity in major depressive disorder (MDD) is well recognized but not well understood. Core depressive features are reward and emotional symptoms, which reflect dysfunctions in the positive valence (PV) and negative valence (NV) systems, respectively. This study assessed whether PV and NV systems (based on selected symptoms) were associated with different clinical features, antidepressant response, and levels of immunomarkers in adults with MDD. METHODS: These analyses used data from combining medications to enhance depression outcomes study (N = 665; n = 166 for immunomarkers). PV and NV symptom scores were extracted from the clinician-rated 30-item Inventory of Depressive Symptomatology. Correlational analyses were conducted. RESULTS: PV and NV symptom scores were substantially associated with different clinical features. PV symptoms (impaired motivation, impaired energy, and anhedonia) were independently associated with female gender (p < .001), older age (p = .012), and higher cognitive and physical impairment (p < .001) according to the 7-item Cognitive and Physical Functioning Questionnaire. Conversely, NV symptoms (anxiety and interpersonal sensitivity) were independently associated with younger age (p = .013), more anxious comorbidities (p = .001 for generalized anxiety disorder and p = .002 for social phobia) and other commonly associated noncriterion symptoms (p < .001). Overall, PV symptoms were more responsive to antidepressants than NV symptoms (p < .0001; Cohen's d = .455). A PV symptom score was positively correlated with the concentration of three proinflammatory and one anti-inflammatory factor. In contrast, an NV symptom score was negatively associated with only one proinflammatory immunomarker. CONCLUSIONS: PV and NV system functions appear to be reflected in selected clinical symptoms that differentially relate to other clinical features, treatment outcomes, and immunological function.

Reduced anti-inflammatory gut microbiota are associated with depression and anhedonia.

INTRODUCTION: Characterise gut microbiota distributions of participants with co-occurring depression and anxiety, in those with only depression or with anxiety, and determine if gut bacteria differentially correlates with distinct clinical presentations. METHODS: Participants (10 healthy controls [mean age: 33, 60% female] and 60 psychiatric subjects; major depressive disorder (comorbid with anxiety), n = 38 [mean age: 39.2, 82% female], anxiety only, n = 8 [mean age: 40.0, 100% female], depression only without anxiety, n = 14 [mean age: 41.9, 79% female]) were characterized by psychiatric assessments. Quantitative PCR and 16S rRNA sequencing were used to characterize the gut microbiota in stool samples. RESULTS: Altered microbiota correlated with pre-defined clinical presentation, with Bacteroides (p = 0.011) and the Clostridium leptum subgroup (p = 0.023) significantly different between clinical categories. Cluster analysis of the total sample using weighted UniFrac ß-diversity of the gut microbiota identified two different clusters defined by differences in bacterial distribution. Cluster 2 had higher Bacteroides (p = 0.006), and much reduced presence of Clostridales (p<0.001) compared to Cluster 1. Bifidobacterium (p = 0.0173) was also reduced in Cluster 2 compared to Cluster 1. When evaluated for clinical charateristics, anhedonia scores in Cluster 2 were higher than in Cluster 1. LIMITATIONS: The sample is smaller and predominately female. CONCLUSIONS: Reduced or absent Clostridia was consistently seen in those with depression, independent of the presence of anxiety. Conversely, reduced Bacteroides may be more associated with the presence of anxiety, independent of the presence of depression. These differences suggest that gut microbiota distribution could help clarify the underlying pathology of comorbid clinical presentation.

Comprehensive phenotyping of depression disease trajectory and risk: Rationale and design of Texas Resilience Against Depression study (T-RAD).

Depression has a chronic and recurrent course often with early onset and is the leading cause of disability worldwide. In contrast to diagnoses for other conditions which rely on precise medical tests, the diagnosis of depression still focuses exclusively on symptom reports. As a result, heterogeneous patient groups are included under broad categories. Furthermore, in the absence of companion diagnostic tests, choosing specific treatments for patients remains imprecise with only one-third of patients entering remission with initial treatment, with others requiring multiple intervention steps to achieve remission. In addition to improving treatment outcomes, disease prevention is essential to reduce overall disease burden. Adolescence is a critical window where complex emotional, social, familial, and biological shifts may predispose to lifelong depression. Thus, personalized medicine, integrating individual variability in genes, brain function, and clinical phenotypes, can offer a comprehensive approach to provide precise diagnosis, novel drug development, optimal treatment assignment, and prevention of illness and its associated burden. Texas Resilience Against Depression study (T-RAD) encompasses two natural history, longitudinal (10 + years), prospective studies (D2K and RAD), each enrolling 2500 participants. The D2K study follows participants (ages 10 years and older) who have a current or past diagnosis of depression or bipolar disorder. The RAD study follows participants aged 10-24 years who are at risk for depression but not yet suffering from the disease. The T-RAD study will help to uncover the socio-demographic, lifestyle, clinical, psychological, and neurobiological factors that contribute to mood disorder onset, recurrence, progression, and differential treatment response.

Can targeted metabolomics predict depression recovery? Results from the CO-MED trial.

Metabolomics is a developing and promising tool for exploring molecular pathways underlying symptoms of depression and predicting depression recovery. The AbsoluteIDQ™ p180 kit was used to investigate whether plasma metabolites (sphingomyelins, lysophosphatidylcholines, phosphatidylcholines, and acylcarnitines) from a subset of participants in the Combining Medications to Enhance Depression Outcomes (CO-MED) trial could act as predictors or biologic correlates of depression recovery. Participants in this trial were assigned to one of three pharmacological treatment arms: escitalopram monotherapy, bupropion-escitalopram combination, or venlafaxine-mirtazapine combination. Plasma was collected at baseline in 159 participants and again 12 weeks later at study exit in 83 of these participants. Metabolite concentrations were measured and combined with clinical and sociodemographic variables using the hierarchical lasso to simultaneously model whether specific metabolites are particularly informative of depressive recovery. Increased baseline concentrations of phosphatidylcholine C38:1 showed poorer outcome based on change in the Quick Inventory of Depressive Symptoms (QIDS). In contrast, an increased ratio of hydroxylated sphingomyelins relative to non-hydroxylated sphingomyelins at baseline and a change from baseline to exit suggested a better reduction of symptoms as measured by QIDS score. All metabolite-based models performed superior to models only using clinical and sociodemographic variables, suggesting that metabolomics may be a valuable tool for predicting antidepressant outcomes.

Adiponectin Moderates Antidepressant Treatment Outcome in the Combining Medications to Enhance Depression Outcomes Randomized Clinical Trial.

BACKGROUND: Major depressive disorder (MDD) is often comorbid with metabolic diseases such as obesity, cardiovascular disease, and type 2 diabetes. A potential link between these disorders is adiponectin, an adipocyte-derived circulating hormone with insulin-sensitizing, anti-inflammatory, and neuroplasticity effects. Reductions in plasma levels of adiponectin have been reported in both humans with depression and in the chronic-defeat mouse model of depression. However, the predictive value of adiponectin for treatment response to depression has not been determined. METHODS: We investigated the potential predictive effect of baseline adiponectin levels in patients who provided plasma and were undergoing one of three pharmacological treatments (escitalopram monotherapy; escitalopram plus bupropion; and venlafaxine plus mirtazapine) in the Combining Medications to Enhance Depression Outcomes clinical trial (n=160). Specifically, we assessed whether adiponectin moderates-that is, differentially predicts-treatment response among the treatment arms. Improvements with treatment were assessed using change in the clinician-rated 30-item Inventory of Depressive Symptomatology (IDS-C) from baseline through week 12. Moderator effects were tested using separate pairwise repeated measures mixed-effects models with a treatment-arm-by-adiponectin interaction. RESULTS: Baseline adiponectin levels moderated treatment outcome between two combination therapies. Specifically, low adiponectin predicted better response to escitalopram plus bupropion compared to venlafaxine plus mirtazapine, whereas high adiponectin predicted better response to venlafaxine plus mirtazapine compared to escitalopram plus bupropion (F=4.84, p=0.03). Adiponectin levels did not correlate with baseline depression severity (r=-0.03, p=.59). CONCLUSIONS: Antidepressant selection for patients with MDD can be personalized using pre-treatment blood-based biomarkers, such as adiponectin, thereby improving treatment outcomes.

Differential effects of antidepressants escitalopram versus lithium on Gs alpha membrane relocalization.

BACKGROUND: Plasma membrane localization can play a significant role in the ultimate function of certain proteins. Specific membrane domains like lipid rafts have been shown to be inhibitory domains to a number of signaling proteins, including Gsα, and chronic antidepressant treatment facilitates Gs signaling by removing Gsα form lipid rafts. The intent of this study is to compare the effects of the selective serotnin reuptake inhibitor, escitalopram, with that of the mood stabilizing drug, lithium. RESULTS: There are a number of mechanisms of action proposed for lithium as a mood stabilizing agent, but the interactions between G proteins (particularly Gs) and mood stabilizing drugs are not well explored. Of particular interest was the possibility that there was some effect of mood stabilizers on the association between Gsα and cholesterol-rich membrane microdomains (lipid rafts), similar to that seen with long-term antidepressant treatment. This was examined by biochemical and imaging (fluorescence recovery after photobleaching: FRAP) approaches. Results indicate that escitalopram was effective at liberating Gsα from lipid rafts while lithium was not. CONCLUSIONS: There are a number of drug treatments for mood disorders and yet there is no unifying hypothesis for a cellular or molecular basis of action. It is evident that there may in fact not be a single mechanism, but rather a number of different mechanisms that converge at a common point. The results of this study indicate that the mood stabilizing agent, lithium, and the selective serotonin reuptake inhibitor, escitalopram, act on their cellular targets through mutually exclusive pathways. These results also validate the hypothesis that translocation of Gsα from lipid rafts could serve as a biosignature for antidepressant action.

Lateral diffusion of Gαs in the plasma membrane is decreased after chronic but not acute antidepressant treatment: role of lipid raft and non-raft membrane microdomains.

GPCR signaling is modified both in major depressive disorder and by chronic antidepressant treatment. Endogenous Gαs redistributes from raft- to nonraft-membrane fractions after chronic antidepressant treatment. Modification of G protein anchoring may participate in this process. Regulation of Gαs signaling by antidepressants was studied using fluorescence recovery after photobleaching (FRAP) of GFP-Gαs. Here we find that extended antidepressant treatment both increases the half-time of maximum recovery of GFP-Gαs and decreases the extent of recovery. Furthermore, this effect parallels the movement of Gαs out of lipid rafts as determined by cold detergent membrane extraction with respect to both dose and duration of drug treatment. This effect was observed for several classes of compounds with antidepressant activity, whereas closely related molecules lacking antidepressant activity (eg, R-citalopram) did not produce the effect. These results are consistent with previously observed antidepressant-induced translocation of Gαs, but also suggest an alternate membrane attachment site for this G protein. Furthermore, FRAP analysis provides the possibility of a relatively high-throughput screening tool for compounds with putative antidepressant activity.

G-protein signaling, lipid rafts and the possible sites of action for the antidepressant effects of n-3 polyunsaturated fatty acids.

Dietary fish oil, a source of polyunsaturated fatty acids (n-3 PUFA), has become increasingly popular for antidepressant therapy, in part because about half of patients treated with conventional antidepressants either fail to remit or discontinue therapy due to side effects. The inception of n-3 PUFA as a putative depression therapeutic may have stemmed from reports suggesting that dietary n-3 PUFA deficiency is linked to both altered membrane PUFA content as well as clinical depression. Several studies have examined n-3 PUFA treatment in depression, either singly or in combination with conventional antidepressant drugs. While results have been encouraging, fish oil treatment remains controversial. At least some of the reason for this is the lack of a defined site of action for n-3 PUFA that would be consistent with an antidepressant effect. This review will address this issue. While it is possible, even likely, that n-3 PUFA have multiple sites of action, this chapter will focus on sites at which n-3 PUFA modify G protein signaling and how those sites relate to both depression and antidepressant action. Much of the focus herein will be on specialized membrane domains (lipid rafts) and the effects that agents modifying those rafts have on elements of G protein signaling cascades. The relevance of specific alterations of G protein signaling for both depression and antidepressant action will be discussed, as will the ability for n-3 PUFA to act either as an antidepressant or in concert with conventional antidepressants.