Exploring the role of neuronal-enriched extracellular vesicle miR-93 and interoception in major depressive disorder

Major depressive disorder (MDD) is associated with interoceptive processing dysfunctions, but the molecular mechanisms underlying this dysfunction are poorly understood. This study combined brain neuronal-enriched extracellular vesicle (NEEV) technology and serum markers of inflammation and metabolism with Functional Magnetic Resonance Imaging (fMRI) to identify the contribution of gene regulatory pathways, in particular micro-RNA (miR) 93, to interoceptive dysfunction in MDD. Individuals with MDD (n = 41) and healthy comparisons (HC; n = 35) provided blood samples and completed an interoceptive attention task during fMRI. EVs were separated from plasma using a precipitation method. NEEVs were enriched by magnetic streptavidin bead immunocapture utilizing a neural adhesion marker (L1CAM/CD171) biotinylated antibody. The origin of NEEVs was validated with two other neuronal markers - neuronal cell adhesion molecule (NCAM) and ATPase Na+/K+ transporting subunit alpha 3 (ATP1A3). NEEV specificities were confirmed by flow cytometry, western blot, particle size analyzer, and transmission electron microscopy. NEEV small RNAs were purified and sequenced. Results showed that: (1) MDD exhibited lower NEEV miR-93 expression than HC; (2) within MDD but not HC, those individuals with the lowest NEEV miR-93 expression had the highest serum concentrations of interleukin (IL)-1 receptor antagonist, IL-6, tumor necrosis factor, and leptin; and (3) within HC but not MDD, those participants with the highest miR-93 expression showed the strongest bilateral dorsal mid-insula activation during interoceptive versus exteroceptive attention. Since miR-93 is regulated by stress and affects epigenetic modulation by chromatin re-organization, these results suggest that healthy individuals but not MDD participants show an adaptive epigenetic regulation of insular function during interoceptive processing. Future investigations will need to delineate how specific internal and external environmental conditions contribute to miR-93 expression in MDD and what molecular mechanisms alter brain responsivity to body-relevant signals.

Leptin's Inverse Association with Brain Morphology and Depressive Symptoms - A Discovery and Confirmatory Study Across Two Independent Samples

BACKGROUND

Major Depressive Disorder (MDD) has a complex, bi-directional relationship with metabolic dysfunction, yet the neural correlates of this association are not well understood.

METHOD

In this cross-sectional investigation, we employed a two-step 'discovery and confirmatory' strategy, utilizing two 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 MDD.

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 (SBC) ranged: -0.27 to -0.49, puncorrected <0.05). 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 (SBC = 0.26 in sample 1, SBC = 0.30 in sample 2, puncorrected < 0.05). We also observed a positive correlation between leptin levels and atypical depressive symptoms in both MDD groups (r = 0.14 in sample 1, r = 0.29 in sample 2, puncorrected < 0.05).

CONCLUSION

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

Increased expression of ER stress, inflammasome activation, and mitochondrial biogenesis-related genes in peripheral blood mononuclear cells in major depressive disorder

A subset of major depressive disorder (MDD) is characterized by immune system dysfunction, but the intracellular origin of these immune changes remains unclear. Here we tested the hypothesis that abnormalities in the endoplasmic reticulum (ER) stress, inflammasome activity and mitochondrial biogenesis contribute to the development of systemic inflammation in MDD. RT-qPCR was used to measure mRNA expression of key organellar genes from peripheral blood mononuclear cells (PBMCs) isolated from 186 MDD and 67 healthy control (HC) subjects. The comparative CT (2-ΔΔCT) method was applied to quantify mRNA expression using GAPDH as the reference gene. After controlling for age, sex, BMI, and medication status using linear regression models, expression of the inflammasome (NLRC4 and NLRP3) and the ER stress (XBP1u, XBP1s, and ATF4) genes was found to be significantly increased in the MDD versus the HC group. After excluding outliers, expression of the inflammasome genes was no longer statistically significant but expression of the ER stress genes (XBP1u, XBP1s, and ATF4) and the mitochondrial biogenesis gene, MFN2, was significantly increased in the MDD group. ASC and MFN2 were positively correlated with serum C-reactive protein concentrations. The altered expression of inflammasome activation, ER stress, and mitochondrial biogenesis pathway components suggest that dysfunction of these organelles may play a role in the pathogenesis of MDD.

Adverse childhood experiences and obesity linked to indicators of gut permeability and inflammation in adult women

Gut permeability may increase cardiovascular disease risk by allowing bacterial components (e.g., lipopolysaccharide or LPS) to enter the bloodstream, leading to low-grade inflammation. People with adverse childhood experiences (ACEs) consistently display evidence of chronic inflammation, but the source of this inflammation, and whether gut permeability may contribute, is unknown. Moreover, whether ACE status may further perturb obesity-associated gut permeability and inflammation is unknown. Women (N = 79, aged 18-84y) free of cardiometabolic diseases and inflammatory conditions and not regularly taking anti-inflammatory medications were included in a 2 × 2 factorial design with low or high ACE status (either 0 ACEs or 3+ ACEs) and body mass index (BMI) (either normal-weight [18.5-24.9 kg/m2; NW] or obesity [>30 kg/m2; OB]) as factors (n = 15-27/group). Serum LPS binding protein (LBP), soluble CD14 (sCD14), fatty-acid binding protein-2 (FABP2), LPS core IgM, and the ratio of LBP:sCD14 were used as indicators of gut permeability. Inflammatory markers C-reactive protein (CRP), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were also measured. Data were analyzed using 2-way ANCOVA (age-adjusted). LBP, LBP:sCD14 and FABP2 were higher in OB versus NW, regardless of ACE status (PBMI < 0.05). Higher ACE status was associated with increased circulating LBP:sCD14 and LPS core IgM (PACE < 0.05). sCD14 was unrelated to BMI or ACEs. CRP was elevated in OB versus NW (PBMI < 0.001) and tended to be higher with 3+ ACEs compared to 0 ACEs (PACE = 0.06). Moreover, TNF-α was greater in 3+ ACEs relative to 0 ACEs (PACE = 0.03). IL-6 was unrelated to BMI or ACE status. No interaction effects were observed for any marker of gut permeability or inflammation. In sum, ACE status and obesity were independently associated with evidence of gut permeability and systemic inflammation but did not interact in relation to indicators of gut permeability.

The effects of cytomegalovirus on brain structure following sport-related concussion

The neurotrophic herpes virus cytomegalovirus is a known cause of neuropathology in utero and in immunocompromised populations. Cytomegalovirus is reactivated by stress and inflammation, possibly explaining the emerging evidence linking it to subtle brain changes in the context of more minor disturbances of immune function. Even mild forms of traumatic brain injury, including sport-related concussion, are major physiological stressors that produce neuroinflammation. In theory, concussion could predispose to the reactivation of cytomegalovirus and amplify the effects of physical injury on brain structure. However, to our knowledge this hypothesis remains untested. This study evaluated the effect of cytomegalovirus serostatus on white and grey matter structure in a prospective study of athletes with concussion and matched contact-sport controls. Athletes who sustained concussion (n = 88) completed MRI at 1, 8, 15 and 45 days post-injury; matched uninjured athletes (n = 73) completed similar visits. Cytomegalovirus serostatus was determined by measuring serum IgG antibodies (n = 30 concussed athletes and n = 21 controls were seropositive). Inverse probability of treatment weighting was used to adjust for confounding factors between athletes with and without cytomegalovirus. White matter microstructure was assessed using diffusion kurtosis imaging metrics in regions previously shown to be sensitive to concussion. T1-weighted images were used to quantify mean cortical thickness and total surface area. Concussion-related symptoms, psychological distress, and serum concentration of C-reactive protein at 1 day post-injury were included as exploratory outcomes. Planned contrasts compared the effects of cytomegalovirus seropositivity in athletes with concussion and controls, separately. There was a significant effect of cytomegalovirus on axial and radial kurtosis in athletes with concussion but not controls. Cytomegalovirus positive athletes with concussion showed greater axial (P = 0.007, d = 0.44) and radial (P = 0.010, d = 0.41) kurtosis than cytomegalovirus negative athletes with concussion. Similarly, there was a significant association of cytomegalovirus with cortical thickness in athletes with concussion but not controls. Cytomegalovirus positive athletes with concussion had reduced mean cortical thickness of the right hemisphere (P = 0.009, d = 0.42) compared with cytomegalovirus negative athletes with concussion and showed a similar trend for the left hemisphere (P = 0.036, d = 0.33). There was no significant effect of cytomegalovirus on kurtosis fractional anisotropy, surface area, symptoms and C-reactive protein. The results raise the possibility that cytomegalovirus infection contributes to structural brain abnormalities in the aftermath of concussion perhaps via an amplification of concussion-associated neuroinflammation. More work is needed to identify the biological pathways underlying this process and to clarify the clinical relevance of this putative viral effect.

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.

Progressive exercise training improves cardiovascular psychophysiological outcomes in young adult women with a history of adverse childhood experiences

Adverse childhood experiences (ACEs) are early-life psychosocial stressors that are associated with poorer mental health and increased cardiovascular disease (CVD) risk in a dose-dependent manner. We examined the feasibility of an 8-wk combined aerobic and resistance exercise training program to improve systolic (SBP) and diastolic blood pressure (DBP), serum endothelin-1 (ET-1), resilience, hope agency, and hope pathways in young women with ACEs. Forty-two healthy women (21 ± 3 yr) with ≥4 (ACE+; n = 28) or 0 ACEs (ACE-; n = 14) participated in this study. Women with ACEs were randomly assigned to an exercise (ACE+EXT; n = 14) or nonexercise control (ACE+CON; n = 14) group, whereas all ACE- participants were assigned to a nonexercise control (n = 14) group. Hope agency and DBP did not change in any group (P ≥ 0.43), but hope pathways improved only in ACE+EXT (means ± SE change; +1.6 ± 0.74 au, P = 0.032, Hedges' g = 0.53). ET-1 decreased in ACE+EXT only (-0.31 ± 0.15 pg/mL, P = 0.043, g = 0.46). Although the interactions for resilience and SBP did not reach significance (P = 0.05-0.06), forced post hoc analyses indicated that resilience improved (+4.9 ± 1.9 au, P = 0.012, g = 0.64) and SBP tended to improve (-4.0 ± 2.0 mmHg, P = 0.053, g = 0.51) in ACE+EXT only. There were significant associations between changes in hope pathways and SBP (ρ = -0.43, P = 0.023) and ET-1 (ρ = -0.53, P = 0.005), and between changes in SBP and ET-1 (ρ = 0.49; P = 0.012) in the ACE+ group. In summary, structured exercise training reduces serum ET-1 levels, improves positive psychological coping, and may improve SBP in young women with ACEs. The relationships among the changes in hope pathways, SBP, and ET-1 suggest a cardiovascular psychophysiological relationship in young women with ACEs.NEW & NOTEWORTHY This randomized controlled pilot trial shows, for the first time, that 8 wk of structured, progressive exercise training lowers serum endothelin-1 (ET-1) and improves positive psychological coping in young women with significant early-life psychosocial stress. Furthermore, the observed associations among changes in psychological attributes, ET-1, and systolic blood pressure signify a potential interplay between positive psychology and cardiovascular disease risk among women with adverse childhood experiences.

Association between inflammation, reward processing, and ibuprofen-induced increases of miR-23b in astrocyte-enriched extracellular vesicles: A randomized, placebo-controlled, double-blind, exploratory trial in healthy individuals

Ibuprofen, a non-steroidal, anti-inflammatory drug, modulates inflammation but may also have neuroprotective effects on brain health that are poorly understood. Astrocyte-enriched extracellular vesicles (AEEVs) facilitate cell-to-cell communication and - among other functions - regulate inflammation and metabolism via microribonucleic acids (miRNAs). Dysfunctions in reward-related processing and inflammation have been proposed to be critical pathophysiological pathways in individuals with mood disorders. This investigation examined whether changes in AEEV cargo induced by an anti-inflammatory agent results in inflammatory modulation that is associated with reward-related processing. Data from a double-blind, randomized, repeated-measures study in healthy volunteers were used to examine the effects of AEEV miRNAs on brain activation during reward-related processing. In three separate visits, healthy participants (N = 20) received a single dose of either placebo, 200 mg, or 600 mg of ibuprofen, completed the monetary incentive delay task during functional magnetic resonance imaging, and provided a blood sample for cytokine and AEEV collection. AEEV miRNA content profiling showed that ibuprofen dose-dependently increased AEEV miR-23b-3p expression with greater increase following the 600 mg administration than placebo. Those individuals who received 600 mg and showed the highest miR-23b-3p expression also showed the (a) lowest serum tumor necrosis factor (TNF) and interleukin-17A (IL-17A) concentrations; and had the (b) highest striatal brain activation during reward anticipation. These results support the hypothesis that ibuprofen alters the composition of miRNAs in AEEVs. This opens the possibility that AEEV cargo could be used to modulate brain processes that are important for mental health.

Acute administration of ibuprofen increases serum concentration of the neuroprotective kynurenine pathway metabolite, kynurenic acid: a pilot randomized, placebo-controlled, crossover study

RATIONALE

At least six different types of antidepressant treatments have been shown to either increase the neuroprotective kynurenine pathway (KP) metabolite, kynurenic acid (KynA), or decrease the neurotoxic KP metabolite, quinolinic acid (QA). Nonsteroidal anti-inflammatory drugs (NSAIDs) including ibuprofen have shown some efficacy in the treatment of depression but their effects on the KP have not been studied in humans.

OBJECTIVES

To evaluate the effect of ibuprofen on circulating KP metabolites.

METHODS

In a randomized, placebo-controlled, crossover study, 20 healthy adults (10 women) received a single oral dose of 200-mg ibuprofen, 600-mg ibuprofen, or placebo in a counterbalanced order (NCT02507219). Serum samples were drawn in the mid-afternoon, 5 h after ibuprofen/placebo administration. KP metabolites were measured blind to visit by tandem mass spectrometry. Data were analyzed with linear mixed effect models. The primary outcome was KynA/QA and the secondary outcome was KynA.

RESULTS

After Bonferroni correction, there was a significant effect of treatment on KynA/QA. The effect was driven by an increase in KynA concentration after the 600-mg dose but not the 200-mg dose relative to placebo (Cohen's d = 1.71). In contrast, both the 200-mg (d = 1.03) and 600-mg (d = 2.05) doses of ibuprofen decreased tryptophan concentrations relative to placebo.

CONCLUSIONS

Given its KynA-elevating effects, ibuprofen could have neuroprotective effects in the context of depression as well as other neuroinflammatory disorders that are characterized by a reduction in KynA.

Behavioral activation therapy for depression is associated with a reduction in the concentration of circulating quinolinic acid

BACKGROUND

An inflammation-induced imbalance in the kynurenine pathway (KP) has been reported in major depressive disorder but the utility of these metabolites as predictive or therapeutic biomarkers of behavioral activation (BA) therapy is unknown.

METHODS

Serum samples were provided by 56 depressed individuals before BA therapy and 29 of these individuals also provided samples after 10 weeks of therapy to measure cytokines and KP metabolites. The PROMIS Depression Scale (PROMIS-D) and the Sheehan Disability Scale were administered weekly and the Beck depression inventory was administered pre- and post-therapy. Data were analyzed with linear mixed-effect, general linear, and logistic regression models. The primary outcome for the biomarker analyses was the ratio of kynurenic acid to quinolinic acid (KynA/QA).

RESULTS

BA decreased depression and disability scores (p's < 0.001, Cohen's d's > 0.5). KynA/QA significantly increased at post-therapy relative to baseline (p < 0.001, d = 2.2), an effect driven by a decrease in QA post-therapy (p < 0.001, uncorrected, d = 3.39). A trend towards a decrease in the ratio of kynurenine to tryptophan (KYN/TRP) was also observed (p = 0.054, uncorrected, d = 0.78). Neither the change in KynA/QA, nor baseline KynA/QA were associated with response to BA therapy.

CONCLUSION

The current findings together with previous research show that electronconvulsive therapy, escitalopram, and ketamine decrease concentrations of the neurotoxin, QA, raise the possibility that a common therapeutic mechanism underlies diverse forms of anti-depressant treatment but future controlled studies are needed to test this hypothesis.

C-Reactive protein and the kynurenic acid to quinolinic acid ratio are independently associated with white matter integrity in major depressive disorder

Kynurenic acid (KynA) and quinolinic acid (QA) are neuroactive kynurenine pathway (KP) metabolites that have neuroprotective and neurotoxic properties, respectively. At least partly as a result of immune activation, the ratio of KynA to QA in the blood is reduced in major depressive disorder (MDD) and has been reported to be positively correlated with gray matter volume in depression. This study examined whether the inflammatory mediator, C-reactive protein (CRP) and the putative neuroprotective index, KynA/QA, were associated with white matter integrity in MDD, and secondly, whether any such associations were independent of each other or whether the effect of CRP was mediated by KynA/QA. One hundred and sixty-six participants in the Tulsa 1000 study with a DSM-V diagnosis of MDD completed diffusion tensor imaging and provided a serum sample for the quantification of CRP, KynA, and QA. Correlational tractography was performed using DSI Studio to map the specific white matter pathways that correlated with CRP and KynA/QA. CRP was negatively related to KynA/QA (standardized beta coefficient, SBC = -0.35 with standard error, Std.E = 0.13, p < 0.01) after controlling for nine possible confounders, i.e., age, sex, body mass index (BMI), medication status, lifetime alcohol use, severity of depression, severity of anxiety, length of illness, and smoking status. Higher concentrations of CRP were associated with decreased white matter integrity (fractional anisotropy, FA) of the bilateral cingulum and fornix after controlling for the nine potential confounders (SBC = -0.43, Std.E = 0.13, p = 0.002). Greater serum KynA/QA was associated with increased white matter integrity of the bilateral fornix, bilateral superior thalamic radiations, corpus callosum, and bilateral cingulum bundles after controlling for the same possible confounders (SBC = 0.26, Std.E = 0.09, p = 0.005). The relationship between CRP and FA was not mediated by KynA/QA. Exploratory analyses also showed that KynA/QA but not CRP was associated with self-reported positive affect, attentiveness, and fatigue measured with the PANASX (SBCs = 0.17-0.23). Taken together, these results are consistent with the hypothesis that within a subgroup of MDD patients, a higher level of systemic inflammation alters the balance of KP metabolism but also raise the possibility that CRP and neuroactive KP metabolites represent independent molecular mechanisms underlying white matter alterations in MDD.

Unpacking determinants and consequences of food insecurity for insulin resistance among people living with HIV: Conceptual framework and protocol for the NOURISH-OK study

Background:

Over the past four decades, advances in HIV treatment have contributed to a longer life expectancy for people living with HIV (PLWH). With these gains, the prevention and management of chronic co-morbidities, such as diabetes, are now central medical care goals for this population. In the United States, food insecurity disproportionately impacts PLWH and may play a role in the development of insulin resistance through direct and indirect pathways. The Nutrition to Optimize, Understand, and Restore Insulin Sensitivity in HIV for Oklahoma (NOURISH-OK) will use a novel, multi-level, integrated framework to explore how food insecurity contributes to insulin resistance among PLWH. Specifically, it will explore how food insecurity may operate as an intermediary risk factor for insulin resistance, including potential linkages between upstream determinants of health and downstream consequences of poor diet, other behavioral risk factors, and chronic inflammation.

Methods/design:

This paper summarizes the protocol for the first aim of the NOURISH-OK study, which involves purposeful cross-sectional sampling of PLWH (n=500) across four levels of food insecurity to test our conceptual framework. Developed in collaboration with community stakeholders, this initial phase involves the collection of anthropometrics, fasting blood samples, non-blood biomarkers, 24-hour food recall to estimate the Dietary Inflammatory Index (DII^®) score, and survey data. A 1-month, prospective observational sub-study (total n=100; n=25 for each food security group) involves weekly 24-hour food recalls and stool samples to identify temporal associations between food insecurity, diet, and gut microbiome composition. Using structural equation modeling, we will explore how upstream risk factors, including early life events, current discrimination, and community food access, may influence food insecurity and its potential downstream impacts, including diet, other lifestyle risk behaviors, and chronic inflammation, with insulin resistance as the ultimate outcome variable. Findings from these analyses of observational data will inform the subsequent study aims, which involve qualitative exploration of significant pathways, followed by development and testing of a low-DII^® food as medicine intervention to reverse insulin resistance among PLWH (ClinicalTrials.gov Identifier: NCT05208671).

Discussion:

The NOURISH-OK study will address important research gaps to inform the development of food as medicine interventions to support healthy aging for PLWH.

Psychiatric symptoms are not associated with circulating CRP concentrations after controlling for medical, social, and demographic factors

Elevated serum concentrations (>3 mg/L) of the acute-phase protein, C-reactive protein (CRP), is used as a clinical marker of inflammation and is reported to be a strong risk factor for cardiovascular disease. In psychiatric populations, CRP concentration is reported to be higher in depressed versus healthy individuals. Positive associations between CRP and depression have been established in both clinical and community samples, but effect sizes are attenuated after controlling for confounding variables. Similarly, emerging research has begun to draw a link between inflammation, symptoms of anxiety, and substance abuse. Given the high level of comorbid anxiety and substance use disorders in many depressed populations, this study examined whether depression (Patient Health Questionnaire 9 [PHQ-9]) and substance use-related (Drug Abuse Screening Test [DAST]) symptoms were associated with CRP concentrations in the blood after adjusting for relevant medical, social, and demographic covariates in a large sample undergoing screening for several transdiagnostic psychiatric research studies. A total of 1,724 participants were analyzed for association of CRP with variables using multivariate linear regression. An unadjusted model with no covariates showed that PHQ-9 was significantly associated with CRP in All (β = 0.125), Female (β = 0.091), and Male (β = 0.154) participants, but DAST was significantly associated with CRP in males only (β = 0.120). For the adjusted model, in both males and females, mood-stabilizer treatment (β = 0.630), opioid medication (β = 0.360), body mass index (β = 0.244), percent body fat (β = 0.289), nicotine use (β = 0.063), and self-reported sleep disturbance (β = 0.061) were significantly associated with increased CRP concentrations. In females, oral contraceptive use (β = 0.576), and waist-to-hip ratio (β = 0.086), and in males, non-steroidal anti-inflammatory drug use (β = 0.367) were also associated with increased CRP concentrations. There was no significant association between CRP and individual depressive, anxiety, or substance use-related symptoms when covariates were included in the regression models. These results suggest that associations between circulating CRP and the severity of psychiatric symptoms are dependent on the type of covariates controlled for in statistical analyses.

Extracellular vesicle-associated cytokines in sport-related concussion

Growing evidence suggests that sport-related concussion results in a robust inflammatory response that can be measured in serum or plasma and is predictive of symptom recovery. Recently, extracellular vesicles (EV) derived from serum or plasma have emerged as a promising source of biomarkers for neurological disorders like concussion because they may better reflect central immunological activity. However, the association of acute concussion with EV-associated cytokines has not yet been systematically studied in humans. We tested the hypothesis that EV-associated cytokines are elevated acutely and predictive of symptom duration following concussion in a cohort of high-school and collegiate football players. Players were enrolled and provided serum samples at a preseason baseline visit (N = 857). An additional blood draw was obtained in players that subsequently suffered a concussion (N = 23) within 6-hours post-injury and in matched, uninjured players (N = 44). Concentrations of Interleukin-6 (IL-6), IL-1β, IL-1 receptor antagonist (IL-1RA), IL-10, and tumor necrosis factor were measured in EV and EV-depleted serum samples. EV-associated IL-6 was significantly elevated post-injury relative to baseline levels and controls (ps < 0.01). In EV-depleted samples, IL-1RA was significantly elevated post-injury relative to baseline levels and controls (ps < 0.01). Time-to-event analyses showed that post-injury EV-associated IL-6 levels were positively associated with the number of days that injured athletes reported symptoms (p < 0.05). These results highlight the potential of EV-associated cytokines as biomarkers of concussion.

Neuronally-enriched exosomal microRNA-27b mediates acute effects of ibuprofen on reward-related brain activity in healthy adults: a randomized, placebo-controlled, double-blind trial

This double-blind, randomized, within-subjects design evaluated whether acute administration of an anti-inflammatory drug modulates neuron-specific, inflammation-modulating microRNAs linked to macroscopic changes in reward processing. Twenty healthy subjects (10 females, 10 males) underwent a functional magnetic resonance imaging scan while performing a monetary incentive delay (MID) task and provided blood samples after administration of placebo, 200 mg, or 600 mg of ibuprofen. Neuronally-enriched exosomal microRNAs were extracted from serum and sequenced. Results showed that: (1) 600 mg of ibuprofen exhibited higher miR-27b-3p, miR-320b, miR-23b and miR-203a-3p expression than placebo; (2) higher mir-27b-3p was associated with lower insula activation during MID loss anticipation; and (3) there was an inverse relationship between miR-27b-3p and MID gain anticipation in bilateral putamen during placebo, a pattern attenuated by both 200 mg and 600 mg of ibuprofen. These findings are consistent with the hypothesis that miR-27b could be an important messaging molecule that is associated with regulating the processing of positive or negative valenced information.

Association between cytomegalovirus infection, reduced gray matter volume, and resting-state functional hypoconnectivity in major depressive disorder: a replication and extension

Human cytomegalovirus (HCMV) is a neurotropic herpes virus known to cause neuropathology in patients with impaired immunity. Previously, we reported a reduction in the gray matter volume (GMV) of several brain regions in two independent samples of participants who were seropositive for HCMV (HCMV+) compared to matched participants who were seronegative for HCMV (HCMV-). In addition to an independent replication of the GMV findings, this study aimed to examine whether HCMV+ was associated with differences in resting-state functional connectivity (rsfMRI-FC). After balancing on 11 clinical/demographic variables using inverse probability of treatment weighting (IPTW), GMV and rsfMRI-FC were obtained from 99 participants with major depressive disorder (MDD) who were classified into 42 HCMV+ and 57 HCMV- individuals. Relative to the HCMV- group, the HCMV+ group showed a significant reduction of GMV in nine cortical regions. Volume reduction in the right lateral orbitofrontal cortex (standardized beta coefficient (SBC) = -0.32, [95%CI, -0.62 to -0.02]) and the left pars orbitalis (SBC = -0.34, [95%CI, -0.63 to -0.05]) in the HCMV+ group was also observed in the previous study. Regardless of the parcellation method or analytical approach, relative to the HCMV- group, the HCMV+ group showed hypoconnectivity between the hubs of the sensorimotor network (bilateral postcentral gyrus) and the hubs of the salience network (bilateral insula) with effect sizes ranging from SBC = -0.57 to -0.99. These findings support the hypothesis that a positive HCMV serostatus is associated with altered connectivity of regions that are important for stress and affective processing and further supports a possible etiological role of HCMV in depression.

Impact of ibuprofen and peroxisome proliferator-activated receptor gamma on emotion-related neural activation: A randomized, placebo-controlled trial

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen have shown initial promise in producing antidepressant effects. This is perhaps due to these drugs being peroxisome proliferator-activated receptor gamma (PPARγ) agonists, in addition to their inhibition of cyclooxygenase enzymes. Some, albeit mixed, evidence suggests that PPARγ agonists have antidepressant effects in humans and animals. This double-blind, placebo-controlled, pharmacologic functional magnetic resonance imaging (ph-fMRI) study aimed to elucidate the impact of ibuprofen on emotion-related neural activity and determine whether observed effects were due to changes in PPARγ gene expression. Twenty healthy volunteers completed an emotional face matching task during three fMRI sessions, conducted one week apart. Placebo, 200 mg, or 600 mg ibuprofen was administered 1 h prior to each scan in a pseudo-randomized order. Peripheral blood mononuclear cells were collected at each session to isolate RNA for PPARγ gene expression. At the doses used, ibuprofen did not significantly change PPARγ gene expression. Ibuprofen dose was associated with decreased blood oxygen level-dependent (BOLD) activation in the dorsolateral prefrontal cortex and fusiform gyrus during emotional face processing (faces-shapes). Additionally, PPARγ gene expression was associated with increased BOLD activation in the insula and transverse and superior temporal gyri (faces-shapes). No interaction effects between ibuprofen dose and PPARγ gene expression on BOLD activation were observed. Thus, results suggest that ibuprofen and PPARγ may have independent effects on emotional neurocircuitry. Future studies are needed to further delineate the roles of ibuprofen and PPARγ in exerting antidepressant effects in healthy as well as clinical populations.

Childhood psychosocial stress is linked with impaired vascular endothelial function, lower SIRT1, and oxidative stress in young adulthood

Adverse childhood experiences (ACEs) are psychosocial stressors that occur during sensitive developmental windows and are associated with increased lifetime cardiovascular disease (CVD) risk in a dose-dependent manner. Vascular endothelial dysfunction is a pathophysiological mechanism that promotes hypertension and CVD and may be a mechanism by which ACEs contribute to lifetime CVD risk. We examined whether exposure to ACEs is associated with reduced vascular endothelial function (VEF) in otherwise healthy, young adult women (20.7 ± 3 yr) with (ACE⁺) versus without (ACE^-) ACEs, explored whether differences in circulating sirtuin 1 (SIRT1) or systemic oxidative stress could explain ACEs-related differences in VEF, and examined the ability of a pilot, 8-wk exercise intervention to augment VEF and SIRT1 or reduce oxidized LDL cholesterol (oxLDL) in ACE⁺ young adult women. Forty-two otherwise healthy young adults completed this study. Prior to the intervention, VEF (P = 0.002) and SIRT1 (P = 0.004) were lower in the ACE⁺ than ACE^- group, but oxLDL concentrations were not different (P = 0.77). There were also significant relationships (P ≤ 0.04) among flow-mediated dilation (FMD), SIRT1, and oxLDL in the ACE⁺, but not ACE^- group. Adjusting for circulating SIRT1 and oxLDL reduced the differences in FMD observed between groups (P = 0.10), but only SIRT1 was a significant adjuster of the means (P < 0.05). Finally, the exercise intervention employed was unable to enhance VEF or SIRT1 in the ACE⁺ exercise group. Our data suggest that ACEs likely increase susceptibility to hypertension and CVD by causing endothelial dysfunction, perhaps through a SIRT1 pathway-related mechanism.NEW & NOTEWORTHY Our study provides novel evidence that young adult women with moderate-to-severe adverse childhood experience (ACE) exposure present impaired endothelial function and lower circulating sirtuin 1 (SIRT1) concentrations than age-matched controls. However, an 8-wk exercise intervention was unable to augment endothelial function or SIRT1 concentrations in a subset of those with ACEs. Our data suggest that ACEs-related impairments in endothelial function may be secondary to decreased NO bioavailability via SIRT1 and/or oxidative stress-related mechanisms.

Common Data Elements, Scalable Data Management Infrastructure, and Analytics Workflows for Large-Scale Neuroimaging Studies

Neuroscience studies require considerable bioinformatic support and expertise. Numerous high-dimensional and multimodal datasets must be preprocessed and integrated to create robust and reproducible analysis pipelines. We describe a common data elements and scalable data management infrastructure that allows multiple analytics workflows to facilitate preprocessing, analysis and sharing of large-scale multi-level data. The process uses the Brain Imaging Data Structure (BIDS) format and supports MRI, fMRI, EEG, clinical, and laboratory data. The infrastructure provides support for other datasets such as Fitbit and flexibility for developers to customize the integration of new types of data. Exemplar results from 200+ participants and 11 different pipelines demonstrate the utility of the infrastructure.

Replicable association between human cytomegalovirus infection and reduced white matter fractional anisotropy in major depressive disorder

Major depressive disorder (MDD) is associated with reductions in white matter microstructural integrity as measured by fractional anisotropy (FA), an index derived from diffusion tensor imaging (DTI). The neurotropic herpesvirus, human cytomegalovirus (HCMV), is a major cause of white matter pathology in immunosuppressed populations but its relationship with FA has never been tested in MDD despite the presence of inflammation and weakened antiviral immunity in a subset of depressed patients. We tested the relationship between FA and HCMV infection in two independent samples consisting of 176 individuals with MDD and 44 healthy controls (HC) (Discovery sample) and 88 participants with MDD and 48 HCs (Replication sample). Equal numbers of HCMV positive (HCMV+) and HCMV negative (HCMV-) groups within each sample were balanced on ten different clinical/demographic variables using propensity score matching. Anti-HCMV IgG antibodies were measured using a solid-phase ELISA. In the Discovery sample, significantly lower FA was observed in the right inferior fronto-occipital fasciculus (IFOF) in HCMV+ participants with MDD compared to HCMV- participants with MDD (cluster size 1316 mm3; pFWE < 0.05, d = -0.58). This association was confirmed in the replication sample by extracting the mean FA from this exact cluster and applying the identical statistical model (p < 0.05, d = -0.45). There was no significant effect of diagnosis or interaction between diagnosis and HCMV in either sample. The effect of chronic HCMV infection on white matter integrity may-in at-risk individuals-contribute to the psychopathology of depression. These findings may provide a novel target of intervention for a subgroup of patients with MDD.

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."

Childhood Adversity and Perceived Distress from the COVID-19 Pandemic

Childhood exposure to adversity may increase an individual's reactivity to subsequent stressors. In this paper, we examine how adverse childhood experiences (ACEs) are associated with experiencing greater perceived distress during the pandemic. In this volunteer clinical cohort study, 177 pregnant women (ages 16-38) were recruited from two university-affiliated perinatal clinics located in a small metropolitan city between October 2017 and May 2018. Longitudinal data collection is ongoing. The current study includes the 101 women who participated through the eighth and most recent survey conducted in mid-April 2020. OLS regression analyses were used to examine the association between childhood adversity and pandemic-related distress. We found that ACE scores were associated with higher levels of distress (b = .08; se = .03; p < .01) when controlling for demographic characteristics. The addition of loneliness to the model fully mediates the association between ACEs score and distress. Findings suggest that adverse childhood experiences influence COVID-19-related distress due to greater social isolation. Those who had greater adversity during childhood may be less likely to have the social connectedness needed to reduce distress due to the pandemic.

Real-time fMRI neurofeedback amygdala training may influence kynurenine pathway metabolism in major depressive disorder

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rtfMRI-nf LA emotional training reduces depressive symptoms.

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rtfMRI-nf LA training increases KynA/3-HK, a neuroprotective index.

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Baseline KynA/QA is associated with the ability to upregulate the LA.

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In partial responder group LA upregulation positively correlates with KynA/QA.

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In partial responder group LA upregulation inversely correlates with MADRS.

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Modulation of the KP may drive rtfMRI-nf-induced changes in neuroplasticity.

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Non-specific effects cannot be ruled out due to the lack of a sham control.

Real-time fMRI neurofeedback (rtfMRI-nf) left amygdala (LA) training is a promising intervention for major depressive disorder (MDD). We have previously proposed that rtfMRI-nf LA training may reverse depression-associated regional impairments in neuroplasticity and restore information flow within emotion-regulating neural circuits. Inflammatory cytokines as well as the neuroactive metabolites of an immunoregulatory pathway, i.e. the kynurenine pathway (KP), have previously been implicated in neuroplasticity. Therefore, in this proof-of-principle study, we investigated the association between rtfMRI-nf LA training and circulating inflammatory mediators and KP metabolites. Based on our previous work, the primary variable of interest was the ratio of the NMDA-receptor antagonist, kynurenic acid to the NMDA receptor agonist, quinolinic acid (KynA/QA), a putative neuroprotective index. We tested two main hypotheses. i. Whether rtfMRI-nf acutely modulates KynA/QA, and ii. whether baseline KynA/QA predicts response to rtfMRI-nf.

Twenty-nine unmedicated participants who met DSM-5 criteria for MDD based on the Mini-International Neuropsychiatric Interview and had current depressive symptoms (Montgomery-Åsberg Depression Rating Scale (MADRS) score > 6) completed two rtfMRI-nf sessions to upregulate LA activity (Visit1 and 2), as well as a follow-up (Visit3) without rtfMRI-nf. All visits occurred at two-week intervals. At all three visits, the MADRS was administered to participants and serum samples for the quantification of inflammatory cytokines and KP metabolites were obtained. First, the longitudinal changes in the MADRS score and immune markers were tested by linear mixed effect model analysis. Further, utilizing a linear regression model, we investigated the relationship between rtfMRI-nf performance and immune markers. After two sessions of rtfMRI-nf, MADRS scores were significantly reduced (t[58] = −4.07, p = 0.009, d = 0.56). Thirteen participants showed a ≥ 25% reduction in the MADRS score (the partial responder group). There was a significant effect of visit (F[2,58] = 3.17, p = 0.05) for the neuroprotective index, KynA to 3-hydroxykynurenine (3-HK), that was driven by a significant increase in KynA/3-HK between Visit1 and Visit3 (t[58] = 2.50, p = 0.03, d = 0.38). A higher baseline level of KynA/QA (β = 5.23, p = 0.06; rho = 0.49, p = 0.02) was associated with greater ability to upregulate the LA. Finally, for exploratory purposes correlation analyses were performed between the partial responder and the non-responder groups as well as in the whole sample including all KP metabolites and cytokines. In the partial responder group, greater ability to upregulate the LA was correlated with an increase in KynA/QA after rtfMRI-nf (rho = 0.75, p = 0.03). The results are consistent with the possibility that rtfMRI-nf decreases metabolism down the so-called neurotoxic branch of the KP. Nevertheless, non-specific effects cannot be ruled out due to the lack of a sham control. Future, controlled studies are needed to determine whether the increase in KynA/3HK and KynA/QA is specific to rtfMRI-nf or whether it is a non-specific correlate of the resolution of depressive symptoms. Similarly, replication studies are needed to determine whether KynA/QA has clinical utility as a treatment response biomarker.

Positive association between serum quinolinic acid and functional connectivity following concussion

The molecular mechanisms underlying the diverse psychiatric and neuropathological sequalae documented in subsets of athletes with concussion have not been identified. We have previously reported elevated quinolinic acid (QuinA), a neurotoxic kynurenine pathway metabolite, acutely following concussion in football players with prior concussion. Similarly, work from our group and others has shown that increased functional connectivity strength, assessed using resting state fMRI, occurs following concussion and is associated with worse concussion-related symptoms and outcome. Moreover, other work has shown that repetitive concussion may have cumulative effects on functional connectivity and is a risk factor for adverse outcomes. Understanding the molecular mechanisms underlying these cumulative effects may ultimately be important for therapeutic interventions or the development of prognostic biomarkers. Thus, in this work, we tested the hypothesis that the relationship between QuinA in serum and functional connectivity following concussion would depend on the presence of a prior concussion. Concussed football players with prior concussion (N = 21) and without prior concussion (N = 16) completed a MRI session and provided a blood sample at approximately 1 days, 8 days, 15 days, and 45 days post-injury. Matched, uninjured football players with (N = 18) and without prior concussion (N = 24) completed similar visits. The association between QuinA and global connectivity strength differed based on group (F(3, 127) = 3.46, p = 0.019); post-hoc analyses showed a positive association between QuinA and connectivity strength in concussed athletes with prior concussion (B = 16.05, SE = 5.06, p = 0.002, 95%CI[6.06, 26.03]), but no relationship in concussed athletes without prior concussion or controls. Region-specific analyses showed that this association was strongest in bilateral orbitofrontal cortices, insulae, and basal ganglia. Finally, exploratory analyses found elevated global connectivity strength in concussed athletes with prior concussion who reported depressive symptoms at the 1-day visit compared to those who did not report depressive symptoms (t(15) = 2.37, mean difference = 13.50, SE = 5.69, p = 0.032, 95%CI[1.36, 25.63], Cohen's d = 1.15.). The results highlight a potential role of kynurenine pathway (KP) metabolites in altered functional connectivity following concussion and raise the possibility that repeated concussion has a "priming" effect on KP metabolism.

Systemic inflammation moderates the association of prior concussion with hippocampal volume and episodic memory in high school and collegiate athletes

BACKGROUND

There is a need to determine why prior concussion has been associated with adverse outcomes in some retired and active athletes. We examined whether serum inflammatory markers moderate the associations of prior concussion with hippocampal volumes and neurobehavioral functioning in active high school and collegiate athletes.

METHODS

Athletes (N = 201) completed pre-season clinical testing and serum collection (C-reactive protein [CRP]; Interleukin-6 [IL]-6; IL-1 receptor antagonist [RA]) and in-season neuroimaging. Linear mixed-effects models examined associations of prior concussion with inflammatory markers, self-reported symptoms, neurocognitive function, and hippocampal volumes. Models examined whether inflammatory markers moderated associations of concussion history and hippocampal volume and/or clinical measures.

RESULTS

Concussion history was significantly associated with higher symptom severity, p = 0.012, but not hippocampal volume or inflammatory markers (ps > 0.05). A significant interaction of prior concussion and CRP was observed for hippocampal volume, p = 0.006. Follow-up analyses showed that at high levels of CRP, athletes with two or more prior concussions had smaller hippocampal volume compared to athletes without prior concussion, p = 0.008. There was a significant interaction between prior concussion and levels of IL-1RA on memory scores, p = 0.044, i.e., at low levels of IL-1RA, athletes with two or more concussions had worse memory performance than those without prior concussion (p = 0.014).

CONCLUSION

Findings suggest that certain markers of systemic inflammation moderate the association between prior concussion and hippocampal volume and episodic memory performance. Current findings highlight potential markers for predicting at-risk individuals and identify therapeutic targets for mitigating the long-term adverse consequences of cumulative concussion.

Prospective study of the effects of sport-related concussion on serum kynurenine pathway metabolites

Reports of neurodegenerative and psychiatric disease in former athletes have increased public concern about the acute and chronic effects of sport-related concussions (SRC). The biological factors underlying individual differences in the psychiatric sequalae of SRC and their role in potential long-term negative outcomes have not been determined. One understudied biological consequence of the known inflammatory response to concussion is the activation of a key immunoregulatory pathway, the kynurenine pathway (KP). Activation of the KP produces several neuroactive metabolites that have been associated with psychiatric and neurodegenerative diseases. We tested the hypothesis that SRC results in an elevation of serum KP metabolites with neurotoxic properties (quinolinic acid [QuinA], 3-hydroxykynurenine [3HK]) together with a reduction in the neuroprotective metabolite kynurenic acid (KynA), and that these metabolites would predict post-concussion psychological symptoms. Additionally, because brain injury is thought to prime the immune system, a secondary goal was to test the hypothesis that athletes with acute SRC and a history of prior SRC would have elevated neurotoxic relative to neuroprotective KP metabolites compared to athletes that were concussed for the first time. High school and collegiate football players (N = 1136) were enrolled at a preseason baseline visit that included clinical testing and blood specimen collection. Athletes that suffered a SRC (N = 59) completed follow-up visits within 6-hours (early-acute), at 24-48 h (late-acute) and at 8, 15, and 45 days post-injury. Uninjured contact sport (CC; N = 54) and non-contact sport athletes completed similar visits and served as controls (NCC; N = 30). SRC athletes had significantly elevated psychological symptoms, assessed using the Brief Symptom Inventory-18 (BSI), acutely following injury relative to both control groups. There was a group-by-visit interaction on the ratio of KynA to 3HK in serum, a neuroprotective index, with elevated KynA/3HK in athletes with SRC at the early-acute visit relative to later visits. Importantly, athletes with greater elevation in this neuroprotective index at the early-acute visit reported fewer depressive symptoms at the late-acute visit. Finally, SRC athletes with prior concussion had significantly lower serum KynA/QuinA at all visits compared to SRC athletes with no prior concussion, an effect driven by elevated QuinA in SRC athletes with prior concussion. These results suggest that early-acute activation of the KynA branch of the KP may protect against the development of depressive symptoms following concussion. Furthermore, they highlight the potential of serum QuinA as a biomarker for repetitive head injury and provide insight into possible mechanisms linking prior concussion with subsequent injury.

A Prospective Study of Acute Blood-Based Biomarkers for Sport-Related Concussion

OBJECTIVE

Prospectively characterize changes in serum proteins following sport-related concussion and determine whether candidate biomarkers discriminate concussed athletes from controls and are associated with duration of symptoms following concussion.

METHODS

High school and collegiate athletes were enrolled between 2015 and 2018. Blood was collected at preinjury baseline and within 6 hours (early acute) and at 24 to 48 hours (late acute) following concussion in football players (n = 106), matched uninjured football players (n = 84), and non-contact-sport athletes (n = 50). Glial fibrillary acidic protein, ubiquitin c-terminal hydrolase-L1, S100 calcium binding protein B, alpha-II-spectrin breakdown product 150, interleukin 6, interleukin 1 receptor antagonist, and c-reactive protein were measured in serum. Linear models assessed changes in protein concentrations over time. Receiver operating curves quantified the discrimination of concussed athletes from controls. A Cox proportional hazard model determined whether proteins were associated with symptom recovery.

RESULTS

All proteins except glial fibrillary acidic protein and c-reactive protein were significantly elevated at the early acute phase postinjury relative to baseline and both control groups and discriminated concussed athletes from controls with areas under the curve of 0.68 to 0.84. The candidate biomarkers also significantly improved the discrimination of concussed athletes from noncontact controls compared to symptom severity alone. Glial fibrillary acidic protein was elevated postinjury relative to baseline in concussed athletes with a loss of consciousness or amnesia. Finally, early acute levels of interleukin 1 receptor antagonist were associated with the number of days to symptom recovery.

INTERPRETATION

Brain injury and inflammatory proteins show promise as objective diagnostic biomarkers for sport-related concussion, and inflammatory markers may provide prognostic value. ANN NEUROL 2020;87:907-920.

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.

Acute elevation of serum inflammatory markers predicts symptom recovery after concussion

OBJECTIVE

To test the hypothesis that acute elevations in serum inflammatory markers predict symptom recovery after sport-related concussion (SRC).

METHODS

High school and collegiate football players (n = 857) were prospectively enrolled. Forty-one athletes with concussion and 43 matched control athletes met inclusion criteria. Serum levels of interleukin (IL)-6, IL-1β, IL-10, tumor necrosis factor, C-reactive protein, interferon-γ, and IL-1 receptor antagonist and Sport Concussion Assessment Tool, 3rd edition (SCAT3) symptom severity scores were collected at a preinjury baseline, 6 and 24-48 hours postinjury, and approximately 8, 15, and 45 days following concussion. The number of days that athletes were symptomatic following SRC (i.e., duration of symptoms) was the primary outcome variable.

RESULTS

IL-6 and IL-1RA were significantly elevated in athletes with concussion at 6 hours relative to preinjury and other postinjury visits, as well as compared to controls (ps ≤ 0.001). IL-6 and IL-1RA significantly discriminated concussed from control athletes at 6 hours postconcussion (IL-6 area under receiver operating characteristic curve 0.79 [95% confidence interval (CI) 0.65-0.92], IL-1RA AUC 0.79 [95% CI 0.67-0.90]). Further, IL-6 levels at 6 hours postconcussion were significantly associated with the duration of symptoms (hazard ratio for symptom recovery = 0.61 [95% CI 0.38-0.96], p = 0.031).

CONCLUSIONS

Results support the potential utility of IL-6 and IL-1RA as serum biomarkers of SRC and demonstrate the potential of these markers in identifying athletes at risk for prolonged recovery after SRC.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that serum levels of IL-6 and IL-1RA 6 hours postconcussion significantly discriminated concussed from control athletes.

Association of Early-Life Stress With Cytomegalovirus Infection in Adults With Major Depressive Disorder

This study examines the association of cytomegalovirus infection in adults with major depressive disorder who experienced various forms of childhood stress.

Reduced immunity to measles in adults with major depressive disorder

BACKGROUND

Depression can impair the immunogenicity of vaccine administration in adults. Whereas many vaccinations are administered in childhood, it is not known whether adolescent or adult onset depression is associated with impairments in the maintenance of protection of childhood vaccines. This study tested the hypothesis that individuals with adolescent or adult onset mood disorders would display compromised immunity to measles, a target of childhood vaccination.

METHODS

IgG antibodies to measles were quantified using a solid phase immunoassay in volunteers with bipolar disorder (BD, n = 64, mean age of onset = 16.6 ± 5.6), currently depressed individuals with major depressive disorder (cMDD, n = 85, mean age of onset = 17.9 ± 7.0), remitted individuals with a history of MDD (rMDD, n = 82, mean age of onset = 19.2 ± 8.6), and non-depressed comparison controls (HC, n = 202), all born after the introduction of the measles vaccine in the USA in 1963.

RESULTS

Relative to HC, both the cMDD group (p = 0.021, adjusted odds ratios (OR) = 0.47, confidence interval (CI) = 0.24-0.90), and the rMDD group (p = 0.038, adjusted OR = 0.50, CI = 0.26-0.97) were less likely to test seropositive for measles. Compared with unmedicated MDD participants, currently medicated MDD participants had a longer lifetime duration of illness and were less likely to test seropositive for measles.

CONCLUSIONS

Individuals with adolescent or adult onset MDD are less likely to test seropositive for measles. Because lower IgG titers are associated with increased risk of measles infection, MDD may increase the risk and severity of infection possibly because of impaired maintenance of vaccine-related protection from measles.

Identification and replication of RNA-Seq gene network modules associated with depression severity

Genomic variation underlying major depressive disorder (MDD) likely involves the interaction and regulation of multiple genes in a network. Data-driven co-expression network module inference has the potential to account for variation within regulatory networks, reduce the dimensionality of RNA-Seq data, and detect significant gene-expression modules associated with depression severity. We performed an RNA-Seq gene co-expression network analysis of mRNA data obtained from the peripheral blood mononuclear cells of unmedicated MDD (n = 78) and healthy control (n = 79) subjects. Across the combined MDD and HC groups, we assigned genes into modules using hierarchical clustering with a dynamic tree cut method and projected the expression data onto a lower-dimensional module space by computing the single-sample gene set enrichment score of each module. We tested the single-sample scores of each module for association with levels of depression severity measured by the Montgomery-Åsberg Depression Scale (MADRS). Independent of MDD status, we identified 23 gene modules from the co-expression network. Two modules were significantly associated with the MADRS score after multiple comparison adjustment (adjusted p = 0.009, 0.028 at 0.05 FDR threshold), and one of these modules replicated in a previous RNA-Seq study of MDD (p = 0.03). The two MADRS-associated modules contain genes previously implicated in mood disorders and show enrichment of apoptosis and B cell receptor signaling. The genes in these modules show a correlation between network centrality and univariate association with depression, suggesting that intramodular hub genes are more likely to be related to MDD compared to other genes in a module.

Treatment of bipolar depression with minocycline and/or aspirin: an adaptive, 2×2 double-blind, randomized, placebo-controlled, phase IIA clinical trial

Given evidence of chronic inflammation in bipolar disorder (BD), we tested the efficacy of aspirin and minocycline as augmentation therapy for bipolar depression. Ninety-nine depressed outpatients with BD were enrolled in a 6 week, double-blind, placebo-controlled trial, and randomized to one of four groups: active minocycline (100 mg b.i.d.) + active aspirin (81 mg b.i.d.) (M + A); active minocycline + placebo aspirin (M + P); placebo-minocycline + active aspirin (A + P); and placebo-minocycline + placebo aspirin (P + P). A blinded interim analysis mid-way through the study led to the dropping of the M + P and A + P arms from further enrollment giving numbers per group who were included in the final analysis of: 30 (M + A), 18 (M + P), 19 (A + P), and 28 (P + P). When the study started, there were three primary outcome measures. Based on the results of the interim analysis, the primary outcome variable, response to treatment as defined by >50% decrease in Montgomery-Äsberg Depression Rating Scale (MADRS) score was maintained. The other two (i.e., the change in mean MADRS score from baseline to end of study and the remission rate, with remission being defined as a score of <11 on the MADRS) were reduced to exploratory outcome measures because the interim analysis indicated that the study was adequately powered to test differences in response rate but not the mean change in MADRS scores or remission rates. CRP and IL-6 were assayed to measure inflammation. Urinary thromboxane B2 (11-D-TXB₂) concentrations, which were significantly increased at baseline in the combined BD sample (n = 90) vs. a healthy control group (n = 27), served as an indirect marker of cyclooxygenase (COX) activity. In a two-group analysis, the M + A group showed a greater response rate than the P + P group (p(one-tailed) = 0.034, OR = 2.93, NNT = 4.7). When all four arms were included in the analysis, there was a main effect of aspirin on treatment response that was driven by both the M + A and the A + P groups (p(two-tailed) = 0.019, OR = 3.67, NNT = 4.0). Additionally, there was a significant 3-way interaction between aspirin, minocycline, and IL-6, indicating that response to minocycline was significantly greater in participants in the M + P group with higher IL-6 concentrations. Further, participants in the M + P group who responded to treatment had significantly greater decreases in IL-6 levels between baseline and visit 7 vs. non-responders. Regarding the exploratory outcomes, there was a main effect for aspirin on the remission rate (χ₁² = 4.14, p(2t) = 0.04, OR = 2.52, NNT = 8.0). There was no significant main effect of aspirin or minocycline on the mean change in MADRS score across visits. Aspirin and minocycline may be efficacious adjunctive treatments for bipolar depression. Given their potential import, additional studies to confirm and extend these findings are warranted.

Kynurenic acid is reduced in females and oral contraceptive users: Implications for depression

The incidence of depression is approximately 2-fold greater in women than men but the biological mechanisms underlying this phenomenon remain unclear. One potential mechanism that has been understudied is immune function, which is modulated by sex hormones and differs considerably between males and females. The immune-regulating kynurenine pathway previously has been implicated in the pathogenesis of mood disorders. In particular, a decreased ratio of neuroprotective (kynurenic acid; KynA) to neurotoxic (3-hydroxykynurenine; 3HK and quinolinic acid; QA) kynurenine pathway metabolites has been reported in several mood disorder subtypes. Yet there is a paucity of research investigating sex differences in the kynurenine pathway in the context of depression. Similarly, oral contraceptive (OC) use has been shown to be a risk factor for depression but to our knowledge this epidemiological relationship has not been considered within the framework of immune dysfunction. Here, we compared the concentrations of c-reactive protein (CRP) and kynurenine pathway metabolites in a combined sample of subjects with major depressive disorder (MDD), bipolar disorder (BD), and healthy controls (HC) comprising 130 men and 350 women. CRP was measured in a CLIA-certified hospital laboratory. Kynurenine metabolites were quantified using high performance liquid chromatography with tandem mass spectrometry. Estradiol and progesterone were quantified with the Mesoscale Discovery (MSD) platform. After controlling for diagnosis, age, sex, BMI, analysis batch, and self-reported childhood trauma we found that women had significantly lower KynA/3HK and KynA/QA ratios than men, and that these results were driven by a decrease in KynA. There was no significant difference between males and females in the concentration of CRP. Further, women taking OC showed significantly higher levels of CRP and lower ratios of KynA/3HK and KynA/QA compared with women on no form of contraception. Moreover, among women using OC, progesterone concentrations were positively correlated with KynA, KynA/3HK, and KynA/QA. Although preliminary, our results indicate that on average, healthy women show the same pattern of kynurenine pathway metabolism as that observed in subjects with depression. This finding raises the possibility that a reduction in KynA concentrations in women may constitute a vulnerability factor that partly explains the higher incidence of depression in females. Further, the significant association between OC use and reduced KynA as well as increased CRP, could conceivably partially account for the epidemiological association between OC use and depression. Nonetheless, because of the cross-sectional nature of this study, these hypotheses need to be more rigorously tested with longitudinal designs and/or large epidemiological studies.

Sleep disturbance and kynurenine metabolism in depression

OBJECTIVE

Although the interrelationships between sleep disturbance, inflammation, and depression have been found, molecular mechanisms that link these conditions are largely unknown. Kynurenine metabolism is hypothesized to be a key mechanism that links inflammation and depression. Inflammation activates the kynurenine pathway, leading to increases in 3-hydroxykynurenine (3HK) and quinolinic acid (QA), potentially neurotoxic metabolites, and decreases in kynurenic acid (KynA), a potentially neuroprotective compound. This relative neurotoxic shift in the balance of kynurenine metabolites has been associated with depression, but never been examined regarding sleep disturbance. We tested the association between sleep disturbance and this relative neurotoxic shift in 68 currently depressed, 26 previously depressed, and 66 never depressed subjects.

METHODS

Sleep disturbance was assessed using the Pittsburgh Sleep Quality Index. Serum concentrations of kynurenine metabolites were measured using high performance liquid chromatography. Putative neuroprotective indices reflecting the relative activity of neuroprotective and neurotoxic kynurenine metabolites were calculated as KynA/QA and KynA/3HK (primary outcomes).

RESULTS

Sleep disturbance was associated with reduced KynA/QA in the currently depressed group only (unadjusted beta -0.43, p<0.001). This association remained significant even after controlling for age, sex, analysis batch, body-mass index, and depressive symptoms in currently depressed subjects (adjusted beta -0.30, p=0.02). There was no significant association between sleep disturbance and KynA/3HK in any of the groups. Sleep disturbance was associated with increased C-reactive protein in currently depressed subjects only (unadjusted beta 0.38, p=0.007; adjusted beta 0.33, p=0.02).

CONCLUSION

These data support the hypothesis that altered kynurenine metabolism may molecularly link sleep disturbance and depression.

Mood symptoms correlate with kynurenine pathway metabolites following sports-related concussion

OBJECTIVE

An imbalance of neuroactive kynurenine pathway metabolites has been proposed as one mechanism behind the neuropsychiatric sequelae of certain neurological disorders. We hypothesized that concussed football players would have elevated plasma levels of neurotoxic kynurenine metabolites and reduced levels of neuroprotective metabolites relative to healthy football players and that altered kynurenine levels would correlate with post-concussion mood symptoms.

METHODS

Mood scales and plasma concentrations of kynurenine metabolites were assessed in concussed (N=18; 1.61 days post-injury) and healthy football players (N=18). A subset of football players returned at 1-week (N=14; 9.29 days) and 1-month post-concussion (N=14, 30.93 days).

RESULTS

Concussed athletes had significantly elevated levels of quinolinic acid (QUIN) and significantly lower ratios of kynurenic acid (KYNA) to QUIN at all time points compared with healthy athletes (p's<0.05), with no longitudinal evidence of normalization of KYNA or KYNA/QUIN. At 1-day post-injury, concussed athletes with lower levels of the putatively neuroprotective KYNA/QUIN ratio reported significantly worse depressive symptoms (p=0.04), and a trend toward worse anxiety symptoms (p=0.06), while at 1-month higher QUIN levels were associated with worse mood symptoms (p's<0.01). Finally, concussed athletes with worse concussion outcome, defined as number of days until return-to-play, had higher QUIN and lower KYNA/QUIN at 1-month post-injury (p's<0.05).

CONCLUSIONS

These results converge with existing kynurenine literature on psychiatric patients and provide the first evidence of altered peripheral levels of kynurenine metabolites following sports-related concussion.

Smaller Dentate Gyrus and CA2 and CA3 Volumes Are Associated with Kynurenine Metabolites in Collegiate Football Athletes

An imbalance in kynurenine pathway metabolism is hypothesized to be associated with dysregulated glutamatergic neurotransmission, which has been proposed as a mechanism underlying the hippocampal volume loss observed in a variety of neurological disorders. Pre-clinical models suggest that the CA2-3 and dentate gyrus hippocampal subfields are particularly susceptible to excitotoxicity after experimental traumatic brain injury. We tested the hypothesis that smaller hippocampal volumes in collegiate football athletes with (n = 25) and without (n = 24) a concussion history would be most evident in the dentate gyrus and CA2-3 subfields relative to nonfootball healthy controls (n = 27). Further, we investigated whether the concentration of peripheral levels of kynurenine metabolites are altered in football athletes. Football athletes with and without a self-reported concussion history had smaller dentate gyrus (p < 0.05, p < 0.10) and CA2-3 volumes (p's < 0.05) relative to healthy controls. Football athletes with and without a concussion history had a trend toward lower (p < 0.10) and significantly lower (p < 0.05) kynurenine levels compared with healthy controls, while athletes with a concussion history had greater levels of quinolinic acid compared with athletes without a concussion history (p < 0.05). Finally, plasma levels of 3-hydroxykynurenine inversely correlated with bilateral hippocampal volumes in football athletes with a concussion history (p < 0.01), and left hippocampal volume was correlated with the ratio of kynurenic acid to quinolinic acid in football athletes without a concussion history (p < 0.05). Our results raise the possibility that abnormalities of the kynurenine metabolic pathway constitute a mechanism for hippocampal volume differences in the context of sports-related brain injury.

Longitudinal assessment of white matter abnormalities following sports-related concussion

There is great interest in developing physiological-based biomarkers such as diffusion tensor imaging to aid in the management of concussion, which is currently entirely dependent on clinical judgment. However, the time course for recovery of white matter abnormalities following sports-related concussion (SRC) is unknown. We collected diffusion tensor imaging and behavioral data in forty concussed collegiate athletes on average 1.64 days (T1; n = 33), 8.33 days (T2; n = 30), and 32.15 days post-concussion (T3; n = 26), with healthy collegiate contact-sport athletes (HA) serving as controls (n = 46). We hypothesized that fractional anisotropy (FA) would be increased acutely and partially recovered by one month post-concussion. Mood symptoms were assessed using structured interviews. FA differences were assessed using both traditional and subject-specific analyses. An exploratory analysis of tau plasma levels was conducted in a subset of participants. Results indicated that mood symptoms improved over time post-concussion, but remained elevated at T3 relative to HA. Across both group and subject-specific analyses, concussed athletes exhibited increased FA in several white matter tracts at each visit post-concussion with no longitudinal evidence of recovery. Increased FA at T1 and T3 was significantly associated with an independent, real-world outcome measure for return-to-play. Finally, we observed a nonsignificant trend for reduced tau in plasma of concussed athletes at T1 relative to HA, with tau significantly increasing by T2. These results suggest white matter abnormalities following SRC may persist beyond one month and have potential as an objective biomarker for concussion outcome. Hum Brain Mapp 37:833-845, 2016. © 2015 Wiley Periodicals, Inc.

Reduction of kynurenic acid to quinolinic acid ratio in both the depressed and remitted phases of major depressive disorder

Low-grade inflammation is characteristic of a subgroup of currently depressed patients with major depressive disorder (dMDD). It may lead to the activation of the kynurenine-metabolic pathway and the increased synthesis of potentially neurotoxic metabolites such as 3-hydroxykynurenine (3HK) and quinolinic acid (QA), relative to kynurenic acid (KynA). Nevertheless, few studies have examined whether abnormalities in this pathway are present in remitted patients with MDD (rMDD). Here we compared the serum concentrations of kynurenine metabolites, measured using high performance liquid chromatography with tandem mass spectrometry, across 49 unmedicated subjects meeting DSM-IV-TR criteria for MDD, 21 unmedicated subjects meeting DSM-IV-TR criteria for rMDD, and 58 healthy controls (HCs). There was no significant group difference in the concentrations of the individual kynurenine metabolites, however both the dMDD group and the rMDD group showed a reduction in KynA/QA, compared with the HCs. Further, there was an inverse correlation between KynA/QA and anhedonia in the dMDD group, while in the rMDD group, there was a negative correlation between lifetime number of depressive episodes and KynA/QA as well as a positive correlation between the number of months in remission and KynA/QA. Our results raise the possibility that a persistent abnormality exists within the kynurenine metabolic pathway in MDD that conceivably may worsen with additional depressive episodes. The question of whether persistent abnormalities in kynurenine metabolism predispose to depression and/or relapse in remitted individuals remains unresolved.

IL-18 acts in synergy with IL-7 to promote ex vivo expansion of T lymphoid progenitor cells

Although IL-18 has not previously been shown to promote T lymphopoiesis, results obtained via a novel data mining algorithm (global microarray meta-analysis) led us to explore a predicted role for this cytokine in T cell development. IL-18 is a member of the IL-1 cytokine family that has been extensively characterized as a mediator of inflammatory immune responses. To assess a potential role for IL-18 in T cell development, we sort-purified mouse bone marrow-derived common lymphoid progenitor cells, early thymic progenitors (ETPs), and double-negative 2 thymocytes and cultured these populations on OP9-Delta-like 4 stromal layers in the presence or absence of IL-18 and/or IL-7. After 1 wk of culture, IL-18 promoted proliferation and accelerated differentiation of ETPs to the double-negative 3 stage, similar in efficiency to IL-7. IL-18 showed synergy with IL-7 and enhanced proliferation of both the thymus-derived progenitor cells and the bone marrow-derived common lymphoid progenitor cells. The synergistic effect on the ETP population was further characterized and found to correlate with increased surface expression of c-Kit and IL-7 receptors on the IL-18-treated cells. In summary, we successfully validated the global microarray meta-analysis prediction that IL-18 affects T lymphopoiesis and demonstrated that IL-18 can positively impact bone marrow lymphopoiesis and T cell development, presumably via interaction with the c-Kit and IL-7 signaling axis.

Changing the culture of a medical school by orienting students and faculty toward community medicine

Oklahoma's health status has been ranked among the worst in the country. In 1972, the University of Oklahoma established the Tulsa branch of its College of Medicine (COM) to expand the physician workforce for northeastern Oklahoma and to provide care for the uninsured patients of the area. In 2008, the Tulsa branch launched a distinct educational track, the University of Oklahoma COM's School of Community Medicine (SCM), to prepare providers equipped and committed to addressing prevalent health disparities.The authors describe the Tulsa branch's Summer Institute (SI), a signature program of the SCM, and how it is part of SCM's process of institutional transformation to align its education, service, and research missions toward improving the health status of the entire region. The SI is a weeklong, prematriculation immersion experience in community medicine. It brings entering medical and physician assistant students together with students and faculty from other disciplines to develop a shared culture of community medicine. The SI uses an unconventional curriculum, based on Scharmer's Theory U, which emphasizes appreciative inquiry, critical thinking, and collaborative problem solving. Also, the curriculum includes Professional Meaning conversations, small-group sessions to facilitate the integration of students' observations into their professional identities and commitments. Development of prototypes of a better health care system enables participants to learn by doing and to bring community medicine to life.The authors describe these and other curricular elements of the SI, present early evaluation data, and discuss the curriculum's incremental evolution. A longitudinal outcomes evaluation is under way.

Relationship of collegiate football experience and concussion with hippocampal volume and cognitive outcomes

IMPORTANCE

Concussion and subconcussive impacts have been associated with short-term disrupted cognitive performance in collegiate athletes, but there are limited data on their long-term neuroanatomic and cognitive consequences.

OBJECTIVE

To assess the relationships of concussion history and years of football experience with hippocampal volume and cognitive performance in collegiate football athletes.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study conducted between June 2011 and August 2013 at a US psychiatric research institute specializing in neuroimaging among collegiate football players with a history of clinician-diagnosed concussion (n = 25), collegiate football players without a history of concussion (n = 25), and non-football-playing, age-, sex-, and education-matched healthy controls (n = 25).

EXPOSURES

History of clinician-diagnosed concussion and years of football experience.

MAIN OUTCOMES AND MEASURES

High-resolution anatomical magnetic resonance imaging was used to quantify brain volumes. Baseline scores on a computerized concussion-related cognitive battery were used for cognitive assessment in athletes.

RESULTS

Players with and without a history of concussion had smaller hippocampal volumes relative to healthy control participants (with concussion: t48 = 7.58; P < .001; mean difference, 1788 μL; 95% CI, 1317-2258 μL; without concussion: t48 = 4.35; P < .001, mean difference, 1027 μL; 95% CI, 556-1498 μL). Players with a history of concussion had smaller hippocampal volumes than players without concussion (t48 = 3.15; P < .001; mean difference, 761 μL; 95% CI, 280-1242 μL). In both athlete groups, there was a statistically significant inverse relationship between left hippocampal volume and number of years of football played (t46 = -3.62; P < .001; coefficient = -43.54; 95% CI, -67.66 to -19.41). Behavioral testing demonstrated no differences between athletes with and without a concussion history on 5 cognitive measures but did show an inverse correlation between years of playing football and reaction time (ρ42 = -0.43; 95% CI, -0.46 to -0.40; P = .005).

CONCLUSIONS AND RELEVANCE

Among a group of collegiate football athletes, there was a significant inverse relationship of concussion and years of football played with hippocampal volume. Years of football experience also correlated with slower reaction time. Further research is needed to determine the temporal relationships of these findings.

Inflammation and neurological disease-related genes are differentially expressed in depressed patients with mood disorders and correlate with morphometric and functional imaging abnormalities

Depressed patients show evidence of both proinflammatory changes and neurophysiological abnormalities such as increased amygdala reactivity and volumetric decreases of the hippocampus and ventromedial prefrontal cortex (vmPFC). However, very little is known about the relationship between inflammation and neuroimaging abnormalities in mood disorders. A whole genome expression analysis of peripheral blood mononuclear cells yielded 12 protein-coding genes (ADM, APBB3, CD160, CFD, CITED2, CTSZ, IER5, NFKBIZ, NR4A2, NUCKS1, SERTAD1, TNF) that were differentially expressed between 29 unmedicated depressed patients with a mood disorder (8 bipolar disorder, 21 major depressive disorder) and 24 healthy controls (HCs). Several of these genes have been implicated in neurological disorders and/or apoptosis. Ingenuity Pathway Analysis yielded two genes networks, one centered around TNF with NFKβ, TGFβ, and ERK as connecting hubs, and the second network indicating cell cycle and/or kinase signaling anomalies. fMRI scanning was conducted using a backward-masking task in which subjects were presented with emotionally-valenced faces. Compared with HCs, the depressed subjects displayed a greater hemodynamic response in the right amygdala, left hippocampus, and the ventromedial prefrontal cortex to masked sad versus happy faces. The mRNA levels of several genes were significantly correlated with the hemodynamic response of the amygdala, vmPFC and hippocampus to masked sad versus happy faces. Differentially-expressed transcripts were significantly correlated with thickness of the left subgenual ACC, and volume of the hippocampus and caudate. Our results raise the possibility that molecular-level immune dysfunction can be mapped onto macro-level neuroimaging abnormalities, potentially elucidating a mechanism by which inflammation leads to depression.

Minocycline and aspirin in the treatment of bipolar depression: a protocol for a proof-of-concept, randomised, double-blind, placebo-controlled, 2x2 clinical trial

INTRODUCTION

New medication classes are needed to improve treatment effectiveness in the depressed phase of bipolar disorder (BD). Extant evidence suggests that BD is characterised by neural changes such as dendritic remodelling and glial and neuronal cell loss. These changes have been hypothesised to result from chronic inflammation. The principal aims of the proposed research is to evaluate the antidepressant efficacy in bipolar depression of minocycline, a drug with neuroprotective and immune-modulating properties, and of aspirin, at doses expected to selectively inhibit cyclooxygenase 1 (COX-1).

METHODS AND ANALYSIS

120 outpatients between 18 and 55 years of age, who meet DSM-IV-TR criteria for BD (type I or II) and for a current major depressive episode will be recruited to take part in a randomised, double-blind, placebo-controlled, parallel-group, proof-of-concept clinical trial following a 2×2 design. As adjuncts to existing treatment, subjects will be randomised to receive one of the four treatment combinations: placebo-minocycline plus placebo-aspirin, active-minocycline plus placebo-aspirin, placebo-minocycline plus active-aspirin or active-minocycline plus active-aspirin. The dose of minocycline and aspirin is 100 mg twice daily and 81 mg twice daily, respectively. Antidepressant response will be evaluated by assessing changes in the Montgomery-Asberg Depression Rating Scale scores between baseline and the end of the 6-week trial. As secondary outcome measures, the anti-inflammatory effects of minocycline and aspirin will be tested by measuring pre-treatment and post-treatment levels of C reactive protein and inflammatory cytokines.

ETHICS AND DISSEMINATION

Minocycline has been widely used as an antibiotic in doses up to 400 mg/day. Low-dose aspirin has been safely used on a worldwide scale for its role as an antithrombotic and thrombolytic. The study progress will be overseen by a Data, Safety and Monitoring Board, which will meet once every 6 months. Results of the study will be published in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov: NCT01429272.

IL-18 and IL-12 promote development of early thymic progenitors and can substitute for IL-7 in short-term OP9-DL4 co-cultures (64.7)

Determining the most effective parameters for in vitro propagation of T cell precursors is critical for realizing the promise of many envisioned T cell-based immunotherapies. To this end, the consequences of culturing ETP and DN2 thymocytes with IL-18 and IL-1β in the context of the OP9-DL4 co-culture model were evaluated after inference of a hypothesized role for these molecules in thymopoiesis based on results obtained via a novel microarray/literature mining algorithm. Sort-purified mouse ETPs and DN2 thymocytes were cultured on OP9-DL4 stromal layers ±IL-18, IL-1β, IL-12 and/or IL-7 for one week. IL-18 and IL-12 alone promoted proliferation and differentiation of ETPs to the DN3a stage and these cytokines could compensate for absence of IL-7. When IL-18 was used in conjunction with IL-7, synergistic proliferation was observed. IL-1β proved to be deleterious to development and was not overcome by inclusion of IL-7. To evaluate the developmental potential of the derived pre-T cells, culture-generated DN3a-like cells were sort-purified then cultured for an additional 8 days. In these assays, the pre-T cells demonstrated differentiation to the DP stage. Overall, these results indicate that IL-18 and IL-12 can positively impact T cell development and should prove useful in strategies to augment in vitro T cell development in the OP9-DL4 system.

Clinical effects of in situ photoimmunotherapy on late-stage melanoma patients: a preliminary study

Metastatic melanoma is a skin cancer with poor prognosis. In situ photoimmunotherapy (ISPI) is a promising modality for the treatment of metastatic melanoma that combines local, selective photothermal therapy with immunological stimulation. A preliminary clinical study was conducted to evaluate the safety and therapeutic effects of ISPI for late-stage melanoma patients using imiquimod as the immune modifier. Eleven patients received ISPI in one or multiple 6-week treatment cycles applied to a 200-cm2 treatment site, which usually contained multiple cutaneous metastases. ISPI consisted of three main components applied directly to the cutaneous metastases: 1) local application of topical imiquimod; 2) injection of indocyanine green (ICG); and 3) an 805 nm laser for local irradiation. All patients completed at least one cycle of treatment. The most common adverse effects were rash and pruritus at the treatment sites. No grade 4 toxicity was observed. Complete response was observed in six patients. All lesions in the treatment area of the patients responded to ISPI, eight of which achieved complete local response (CLR). CLR was observed in the non-treatment site (regional) lesions in four patients. Five patients were still alive at the time of last follow-up. The probability of 12-month overall survival was 70%. This study demonstrates that ISPI with imiquimod is safe and well tolerated. The patient response rate is promising. ISPI can be easily applied on an outpatient basis and can be combined with other modalities to improve the therapeutic response of metastatic melanoma.

Propagation of common lymphoid progenitors in OP9-DL1 co-culture results in generation of cells incapable of β-selection (36.54)

Common lymphoid progenitors derived from murine bone marrow have previously been demonstrated to be capable of long-term propagation in OP9-DL1 co-cultures. Cultures of this type initially display a wave of differentiation to the double positive stage of T cell development that is observable at three to four weeks post-culture initiation. Continued propagation eventually produces a heterogeneous population of cells that collectively resemble thymocytes derived from animals incapable of β-selection. As TCRβ gene rearrangement occurs at this stage in normal thymocytes, we evaluated the rearrangement status of the co-culture derived cells. Sequential, weekly analysis revealed that TCRβ rearrangements occurred as expected in cultures that differentiated to the DP stage. After the initial wave of DP production however, TCRβ rearrangements were no longer detectable. Further analysis revealed that portions of the CD3 complex were expressed on the derived cells at levels equivalent to or higher than wild-type thymocytes at a similar maturational stage while pre-Tα levels were found to be expressed at a lower level. Finally, by using a novel in vitro β-selection assay, we demonstrate that the cultured cells still do not initiate differentiation past the DN3a stage. These data indicate that while ex vivo derivation and maintenance of T cell precursors is possible, standard OP9-DL1 culture conditions lead to development of cells resistant to induction of the β-selection program.

Differential IL-7 responses in developing human thymocytes

Interleukin (IL)-7 is a factor essential for mouse and human thymopoiesis. Mouse thymocytes have altered sensitivities to IL-7 at different developmental stages. CD4/CD8 double positive (DP) mouse thymocytes are shielded from the influence of IL-7 because of loss of CD127 (IL-7Ralpha). In this study, we assessed IL-7 receptor expression and IL-7 signaling in human thymocytes. We found human DP cells to be severely limited in their ability to phosphorylate STAT-5 in response to IL-7. The relative expression levels of the IL-7-inducible proteins Bcl-2 and Mcl-1 were also lower in human DP cells, consistent with a stage-specific decrease in IL-7 responsiveness. IL-7 responses were restored in a subset of cells that matured past the DP stage. Unlike the regulation of IL-7 signaling in mouse thymocytes, loss of IL-7 signaling in human DP cells was not due to absence of CD127, but instead correlated with downregulation of CD132 (common gamma chain).