Relationships of inflammation trajectories with white matter volume and integrity in midlife

ObjectiveElevated inflammation is associated with worse late-life cognitive functioning and brain health. Our goal was to examine the relationship between inflammation trajectories and white matter integrity in midlife.MethodsParticipants were 508 adults from the Coronary Artery Risk Development in Young Adults Study (CARDIA; 51% female). Latent class analysis was used to identify inflammation trajectories based on repeated measures of the inflammatory marker C-reactive protein (CRP) over the 18 years before brain magnetic resonance imaging (MRI). Outcomes were brain MRI measures of total and region-specific white matter volume and integrity at a mean age of 50.6 ± 3.4 years. Linear regression was used to examine if inflammation trajectories were associated with brain MRI outcomes, adjusting for potential confounds in all models and for disease and health behaviors in follow-up models.ResultsLower-stable (38%), moderate-increasing (7%), and consistently-higher (54%), trajectories emerged. Compared to the lower-stable group, the moderate-increasing group showed lower white matter volume (β = −0.18, 95% CI −0.29, −0.06) and worse white matter integrity as indexed by lower fractional anisotropy (FA; β = −0.37, 95% CI −0.70, −0.04) and higher mean diffusivity (β = 0.44, 95% CI 0.11, 0.78) in the whole brain. The consistently-higher group showed lower whole-brain FA (β = −0.20, −0.38, −0.03). In exploratory analyses, the moderate-increasing group showed lower white matter volume, lower FA and higher MD in the frontal, temporal, and parietal lobes compared to the lower-stable group. The consistently-higher group showed lower white matter volume in the parietal lobe and lower FA in the frontal, temporal, and parietal lobes, but similar MD, compared to the lower-stable group. Findings for the moderate-increasing, but not the consistently-higher, group were robust to adjustment for disease and lifestyle factors.ConclusionIncreasing or high inflammation trajectories from early to mid adulthood are associated with worse brain health, as indexed by lower white matter volume and/or worse white matter integrity.     

Dysconnectivity of a brain functional network was associated with blood inflammatory markers in depression

ObjectiveThere is increasing evidence for a subgroup of major depressive disorder (MDD) associated with heightened peripheral blood inflammatory markers. In this study, we aimed to understand the mechanistic brain-immune axis in inflammation-linked depression by investigating associations between functional connectivity (FC) of brain networks and peripheral blood immune markers in depression.MethodsResting-state functional magnetic resonance imaging (fMRI) and peripheral blood inflammatory markers (C-reactive protein; CRP, interleukin-6; IL-6 and immune cells) were collected on N = 46 healthy controls (HC; CRP ≤ 3 mg/L) and N = 83 cases of depression, stratified further into low CRP cases (loCRP cases; ≤ 3 mg/L; N = 50) and high CRP cases (hiCRP cases; > 3 mg/L; N = 33). In a two-part analysis, network-based statistics (NBS) was firstly used to ascertain whole-brain FC differences in HC vs hiCRP cases. Secondly, we investigated the association between this network of interconnected brain regions and continuous measures of peripheral CRP (N = 83), IL-6 (N = 72), neutrophils and CD4⁺ T-cells (N = 36) in depression cases only.ResultsCase-control NBS testing revealed a single network of abnormally attenuated FC in the high CRP depression cases compared to healthy controls. Connections within this network were mainly between brain regions located in the left insula/frontal operculum and posterior cingulate cortex, which were assigned to ventral attention and default mode canonical fMRI networks respectively. Within-group analysis across all depression cases, secondarily demonstrated that FC within the identified network significantly negatively scaled with CRP, IL-6 and neutrophils.ConclusionsThe findings suggest that inflammation is associated with disruption of functional connectivity within a brain network deemed critical for interoceptive signalling, e.g. accurate communication of peripheral bodily signals such as immune states to the brain, with implications for the pathogenesis of inflammation-linked depression.     

Investigating whether a combination of higher CRP and depression is differentially associated with worse executive functioning in a cohort of 43,896 adults

Many depressed individuals experience difficulties in executive functioning that contribute substantially to functional impairment. It is unknown whether a subtype of depression characterized by chronic inflammation is differentially associated with worse executive functioning. This study examined whether the combination of depression and higher C reactive protein (CRP) is differentially associated with worse executive functioning and whether this association is stronger in older adults. This cross-sectional study analyzed data collected from a population-representative sample of 43,896 adults aged 44.13 years (SD = 13.52) who participated in the baseline assessment of the Lifelines cohort study. Multivariate regression models tested whether depressed individuals (established via structured interview) exhibiting higher levels of inflammation (indexed via high-sensitivity CRP assay following an overnight fast) performed worse on a behavioral test of executive functioning. Depression (B = −3.66, 95% CI: −4.82, −2.49, p < .001) and higher log-transformed CRP (B = −0.67, 95% CI: −0.87,-0.47, p < .001) were associated with worse executive functioning, after adjustment for age, sex, educational attainment, body mass index, smoking status, exposure to stressful life events and chronic stressors, sedentary behavior, and number of chronic medical conditions. Depressed individuals with higher log-transformed CRP exhibited differentially poorer executive functioning (B = −1.09, 95% CI: −2.07,-0.11, p < .001). This association did not differ based on age (B = 0.01, 95% CI: −0.08, 0.10, p = .82). Executive functioning is poorer in depressed individuals with higher CRP, even in early adulthood. Interventions that reduce inflammation may improve cognitive functioning in depression.     

Adverse childhood experiences and depressive symptoms in later life: Longitudinal mediation effects of inflammation

BackgroundAdverse childhood experiences (ACEs) have been associated with both inflammation and depression. However, few studies have examined the role of inflammation as a possible biological mechanism underlying the association of ACEs with depression in later life using longitudinal data. This study investigated the longitudinal mediation effects of inflammation in the relationship between ACEs and depressive symptoms in older adults.MethodsWe utilised data from the English Longitudinal Study of Ageing (N = 4382). ACEs (i.e. threat, family dysfunction, low parental bonding, loss experiences) were assessed retrospectively at wave 3 (2006/07). C-reactive protein (CRP), an inflammatory marker, was measured at waves 2 (2004/05), 4 (2008/09), and 6 (2012/13). Depressive symptoms were ascertained from wave 6 to 8 (2016/17). The mediation analysis was conducted using parallel process latent growth curve modelling.ResultsGreater ACEs cumulative exposure was associated with higher CRP and depressive symptoms at baseline (β_CRPi = 0.066[0.030–0.102]; β_DEPi = 0.149[0.115–0.183]) and with their increase over time (β_CRPs = 0.205[0.095–0.315]; β_DEPs = 0.355[0.184–0.526]). Baseline CRP levels were positively associated with baseline depressive symptoms (β_DEPi = 0.145[0.104–0.186]) and their trajectory (β_DEPs = 0.215[0.124–0.306]). The mediation analysis indicated that higher baseline CRP levels mediated respectively 7% and 5% of the total effect of ACEs cumulative exposure on the baseline value and change in depressive symptoms. These mediation effects were larger for Loss experiences (i.e. 20% and 12% respectively) than for other types of ACEs. In addition, they were independent of possible confounders and additional mediators including adult socioeconomic position and lifestyle factors.ConclusionACEs were related to higher depressive symptoms partly via elevated CRP levels. Inflammation might be one of the psychobiological mechanisms underlying the link between ACEs and depression. Psychosocial and behavioural interventions to prevent and reduce the negative impact of ACEs might help to lower the risk of inflammation and depression in the population.     

The impact of cognitive impairment on perceived workforce performance: Results from the International Mood Disorders Collaborative Project

BackgroundCognitive dysfunction and depression severity are key mediators of workplace adjustment in adults with major depressive disorder (MDD). Herein, we sought to determine the extent to which measures of depression severity and cognitive dysfunction were associated with perceived global disability, workplace performance and quality of life.MethodA post hoc analysis was conducted using data from 260 participants with a diagnosis of DSM-IV-TR-defined MDD who were enrolled in the International Mood Disorders Collaborative Project (IMDCP) between January 2008 and July 2013. Measures of workplace function, global disability, depression severity, cognitive function, and quality of life were employed. These data were analyzed using a multiple variable linear regression equations.ResultsPerceived global disability was significantly predicted by clinical ratings of depression severity (β = 0.54), and perceived inattention (β = 0.24), accounting for 37% of the variance. In addition, perceived inattention (β = 0.58) and clinical ratings of depression severity (β = 0.18), were also significant predictors of perceived workplace productivity/performance, accounting for 38% of the variance. Finally, both clinical ratings of depression severity (β = −0.54), and perceived inattention (β = −0.18) were significant inverse predictors of perceived quality of life, accounting for 34% of the variance.ConclusionThe overarching finding in the analysis herein is that workplace performance variability is explained by subjective measures of cognitive dysfunction to a greater extent than total depression symptom severity. Conversely, total depression symptom severity accounts for a greater degree of variability in global measures of disability relative to cognitive measures. Treatment strategies for adults with major depressive disorder should address issues of cognitive dysfunction to improve workforce participation and performance.     

Accumulation of affective symptoms and midlife cognitive function: The role of inflammation

BackgroundThe aim of the present study was to test whether C-Reactive Protein (CRP), a proxy measure of inflammation, is elevated in people with higher childhood and adulthood affective symptoms and whether elevated CRP predicts midlife cognitive function.MethodsData were used from the National Child Development Study (n = 6276). Measures of memory, verbal fluency, information processing speed and accuracy were available in midlife (age 50). Affective symptoms were assessed in childhood (ages 7, 11, 16) and in adulthood (ages 23, 33, 42, 50). The level of plasma CRP was measured at age 44. Pathway models, unadjusted and fully adjusted for sex, education, childhood socioeconomic position, childhood cognitive ability and affective symptoms at age 50, were fitted to test direct associations between affective symptoms and midlife cognitive function, and indirect associations via the inflammatory pathway (CRP level).ResultsIn a fully adjusted model, there were significant indirect associations between adulthood affective symptoms and immediate memory (β = −0.01, SE = 0.003, p = .03) and delayed memory (β = −0.01, SE = 0.004, p = .03) via CRP. In addition, there were significant indirect associations between affective symptoms in childhood and immediate memory (β = −0.001, SE = 0.00, p = .03) and delayed memory (β = −0.001, SE = 0.001, p = .03), via adulthood affective symptoms and associated CRP. Independent of CRP, there was a significant direct association between adulthood affective symptoms and information processing errors (β = 0.47, SE = 0.21, p = .02). There were no direct or indirect associations between affective symptoms and verbal fluency or information processing speed.ConclusionsCRP at age 44 is elevated in people with higher affective symptoms from age 7 to 42, and elevated CRP is associated with poorer immediate and delayed memory at age 50.     

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

BackgroundMajor 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.MethodsMDD 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.ResultsMDD-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.ConclusionWithin 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 trialsThe 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.”     

Elevated inflammatory markers in women with remitted major depressive disorder and the role of early life maltreatment

Major depressive disorder (MDD) has been linked to elevated inflammation markers. It remains unclear whether the elevation of C-reactive protein (CRP) and interleukin-6 (IL-6) levels are not only observable in acute MDD but also in patients after remission. MDD is a common sequela of early life maltreatment (ELM), which has also been associated with elevated inflammation markers. While the majority of studies investigated (acute) MDD and ELM as isolated predictors of inflammation, a few studies found inflammation levels to be more pronounced in patients with MDD that were exposed to ELM. This investigation included both ELM and MDD in one study and aimed at distinguishing between the effects of MDD in remission (rMDD) and ELM and investigating potential accumulative effects on the inflammatory markers CRP and IL-6 in a population of N = 126 women (n = 122 for CRP and n = 66 for IL-6). We further investigated how disorder characteristics (course and severity) and specific types of ELM affect levels of CRP and IL-6. We found that rMDD predicted levels of CRP and IL-6 and physical abuse predicted levels of CRP when considering both predictors simultaneously, while other types of ELM did not. A later onset of MDD and a shorter time interval since the last episode were associated with higher levels of IL-6. Our findings contribute to the existing literature on the association between MDD and inflammation, suggesting that elevated levels of inflammation markers may persist even after remission of MDD. Our findings on physical abuse as a specific predictor of CRP in the presence of rMDD suggest that different types of ELM could result in distinct inflammation profiles.     

Protein and gene markers of metabolic dysfunction and inflammation together associate with functional connectivity in reward and motor circuits in depression

Bidirectional relationships between inflammation and metabolic dysfunction may contribute to the pathophysiology of psychiatric illnesses like depression. Metabolic disturbances drive inflammation, which in turn exacerbate metabolic outcomes including insulin resistance. Both inflammatory (e.g. endotoxin, vaccination) and metabolic challenges (e.g. glucose ingestion) have been shown to affect activity and functional connectivity (FC) in brain regions that subserve reward and motor processing. We previously reported relationships between elevated concentrations of endogenous inflammatory markers including C-reactive protein (CRP) and low corticostriatal FC, which correlated with symptoms of anhedonia and motor slowing in major depression (MD). Herein, we examined whether similar relationships were observed between plasma markers related to glucose metabolism (non-fasting concentrations of glucose, insulin, leptin, adiponectin and resistin) in 42 medically-stable, unmedicated MD outpatients who underwent fMRI. A targeted, hypothesis-driven approach was used to assess FC between seeds in subdivisions of the ventral and dorsal striatum and a region in ventromedial prefrontal cortex (VS-vmPFC), which was previously found to correlate with both inflammation and symptoms of anhedonia and motor slowing. Associations between FC and gene expression signatures were also explored. A composite score of all 5 glucose-related markers (with increasing values reflecting higher concentrations) was negatively correlated with both ventral striatum (VS)-vmPFC (r = −0.33, p < 0.05) and dorsal caudal putamen (dcP)-vmPFC (r = −0.51, p < 0.01) FC, and remained significant after adjusting for covariates including body mass index (p < 0.05). Moreover, an interaction between the glucose-related composite score and CRP was observed for these relationships (F[2,33] = 4.3, p < 0.05) whereby significant correlations between the glucose-related metabolic markers and FC was found only in patients with high plasma CRP (>3 mg/L; r = −0.61 to −0.81, p < 0.05). Insulin and resistin were the individual markers most predictive of VS-vmPFC and dcP-mPFC FC, respectively, and insulin, resistin and CRP clustered together and in association with both LV-vmPFC and dcP-vmPFC in principal component analyses. Exploratory whole blood gene expression analyses also confirmed that gene probes negatively associated with FC were enriched for both inflammatory and metabolic pathways (FDR p < 0.05). These results provide preliminary evidence that inflammation and metabolic dysfunction contribute jointly to deficits in reward and motor circuits in MD. Future studies using fasting samples and longitudinal and interventional approaches are required to further elucidate the respective contributions of inflammation and metabolic dysfunction to circuits and symptoms relevant to motivation and motor activity, which may have treatment implications for patients with psychiatric illnesses like depression.     

The association between plasma tryptophan catabolites and depression: The role of symptom profiles and inflammation

BackgroundTryptophan catabolites (“TRYCATs”) produced by the kynurenine pathway (KP) may play a role in depression pathophysiology. Studies comparing TRYCATs levels in depressed subjects and controls provided mixed findings. We examined the association of TRYCATs levels with 1) the presence of Major Depressive Disorder (MDD), 2) depressive symptom profiles and 3) inflammatory markers.MethodsThe sample from the Netherlands Study of Depression and Anxiety included participants with current (n = 1100) or remitted (n = 753) MDD DSM-IV diagnosis and healthy controls (n = 642). Plasma levels of tryptophan (TRP), kynurenine (KYN), kynurenic acid (KynA), quinolinic acid (QA), C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor (TNF) were measured. Atypical/energy-related symptom (AES), melancholic symptom (MS) and anxious-distress symptom (ADS) profiles were derived from questionnaires.ResultsAfter adjustment for age, sex, education, smoking status, alcohol consumption and chronic diseases, no significant differences in TRYCATs were found comparing MDD cases versus controls. The MS profile was associated (q < 0.05) with lower KynA (β = -0.05), while AES was associated with higher KYN (β = 0.05), QA (β = 0.06) and TRP (β = 0.06). Inflammatory markers were associated with higher KYN (CRP β = 0.12, IL-6 β = 0.08, TNF β = 0.10) and QA (CRP β = 0.21, IL-6 β = 0.12, TNF β = 0.18). Significant differences against controls emerged after selecting MDD cases with high (top 30%) CRP (KYN d = 0.20, QA d = 0.33) and high TNF (KYN d = 0.24; QA d = 0.39).ConclusionsTRYCATs levels were related to specific clinical and biological features, such as atypical symptoms or a proinflammatory status. Modulation of KP may potentially benefit a specific subset of depressed patients. Clinical studies should focus on patients with clear evidence of KP dysregulations.     

Sleep and brain morphological changes in the eighth decade of life

ObjectiveSleep is important for brain health. We analysed associations between usual sleep habits and magnetic resonance imaging (MRI) markers of neurodegeneration (brain atrophy), vascular damage (white matter hyperintensities, WMH) and waste clearance (perivascular spaces, PVS) in older community-dwelling adults.MethodWe collected self-reported usual sleep duration, quality and medical histories from the Lothian Birth Cohort 1936 (LBC1936) age 76 years and performed brain MRI. We calculated sleep efficiency, measured WMH and brain volumes, quantified PVS, and assessed associations between sleep measures and brain markers in multivariate models adjusted for demographic and medical history variables.ResultsIn 457 subjects (53% males, mean age 76 ± 0.65 years), we found: brain and white matter loss with increased weekend daytime sleep (β = −0.114, P = 0.03; β = −0.122, P = 0.007 respectively), white matter loss with less efficient sleep (β = 0.132, P = 0.011) and PVS increased with interrupted sleep (OR 1.84 95% CI, P = 0.025).ConclusionCross-sectional associations of sleep parameters with brain atrophy and more PVS suggest adverse relationships between usual sleep habits and brain health in older people that should be evaluated longitudinally.     

Increased serum peripheral C-reactive protein is associated with reduced brain barriers permeability of TSPO radioligands in healthy volunteers and depressed patients: implications for inflammation and depression

The relationship between peripheral and central immunity and how these ultimately may cause depressed behaviour has been the focus of a number of imaging studies conducted with Positron Emission Tomography (PET). These studies aimed at testing the immune-mediated model of depression that proposes a direct effect of peripheral cytokines and immune cells on the brain to elicit a neuroinflammatory response via a leaky blood–brain barrier and ultimately depressive behaviour. However, studies conducted so far using PET radioligands targeting the neuroinflammatory marker 18 kDa translocator protein (TSPO) in patient cohorts with depression have demonstrated mild inflammatory brain status but no correlation between central and peripheral immunity.To gain a better insight into the relationship between heightened peripheral immunity and neuroinflammation, we estimated blood-to-brain and blood-to-CSF perfusion rates for two TSPO radiotracers collected in two separate studies, one large cross-sectional study of neuroinflammation in normal and depressed cohorts (N = 51 patients and N = 25 controls) and a second study where peripheral inflammation in N = 7 healthy controls was induced via subcutaneous injection of interferon (IFN)-α. In both studies we observed a consistent negative association between peripheral inflammation, measured with c-reactive protein P (CRP), and radiotracer perfusion into and from the brain parenchyma and CSF. Importantly, there was no association of this effect with the marker of BBB leakage S100β, that was unchanged.These results suggest a different model of peripheral-to-central immunity interaction whereas peripheral inflammation may cause a reduction in BBB permeability. This effect, on the long term, is likely to disrupt brain homeostasis and induce depressive behavioural symptoms.     

Association of peripheral inflammatory markers with connectivity in large-scale functional brain networks of non-demented older adults

BackgroundSystemic inflammation has emerged as a risk factor for cognitive decline and Alzheimer’s disease, but inflammation’s effect on distributed brain networks is unclear. We examined the relationship between peripheral inflammatory markers and subsequent functional connectivity within five large-scale cognitive networks and evaluated the modifying role of cortical amyloid and APOE ε4 status.MethodsBlood levels of soluble tumor necrosis factor-alpha receptor-1 and interleukin 6 were assessed in 176 participants (at baseline mean age: 65 (SD 9) years; 63% women; 85% cognitively normal, 15% mild cognitive impairment (MCI)) and were combined to derive an Inflammatory Index. Approximately six years later, participants underwent resting-state functional magnetic resonance imaging to quantify functional connectivity; a subset of 137 participants also underwent ¹¹C Pittsburgh compound-B (PiB) PET imaging to assess cortical amyloid burden.ResultsUsing linear regression models adjusted for demographic characteristics and cardiovascular risk factors, a higher Inflammatory Index was associated with lower connectivity within the Default Mode (β = −0.013; 95% CI: −0.023, −0.003) and the Dorsal Attention Networks (β = −0.017; 95% CI: −0.028, −0.006). The strength of these associations did not vary by amyloid status (positive/negative). However, there was a significant interaction between Inflammatory Index and APOE ε4 status, whereby ε4-positive participants with a higher Inflammatory Index demonstrated lower connectivity. Inflammatory Index was unrelated to connectivity within other large-scale cognitive networks (Control, Limbic, and Salience/Ventral Attention networks).ConclusionPeripheral pro-inflammatory signaling in older adults without dementia, especially among APOE ε4-positive individuals, is associated with altered connectivity within two large-scale cognitive networks.     

Peripheral blood nerve growth factor levels in major psychiatric disorders

Nerve growth factor (NGF) plays crucial roles in promoting neural growth and survival, and mediating synaptic and morphological plasticity. Several studies investigated the correlation between peripheral NGF levels and major psychiatric disorders, including schizophrenia (SCZ), major depressive disorder (MDD) and bipolar disorder (BPD); however, the findings were inconsistent. This meta-analysis sought to investigate blood NGF levels in patients with psychiatric disorders compared with healthy subjects and examined potential effects of blood fraction, medication and disease status. A total of 21 eligible studies, encompassing 1342 patients suffering from psychiatric disorders and 1225 healthy subjects, were enrolled in the present meta-analysis. No obvious publication bias was observed either for SCZ, MDD or BPD by the Begg's test (P > 0.05). Random-effects meta-analysis showed that SCZ (Z = 2.14, P = 0.033, SMD = −1.08, 95% CI = −2.07 to −0.09) and MDD (Z = 2.57, P = 0.010, SMD = −0.61, 95% CI = −1.08 to −0.14) patients had significantly reduced NGF levels, compared with healthy controls. Notably, this decrease was enhanced in un-medicated patients of SCZ (P = 0.004) and medicated or chronic patients of MDD (P < 0.001). No significant difference of NGF levels was observed between BPD patients and controls (P > 0.05). These results supported an association between the reduction of NGF levels and psychiatric disorders. It remains unclear whether the change of NGF levels is a prerequisite for its function in psychiatric disorders development or merely an epiphenomenon unrelated to the pathophysiologic mechanisms.     

Are all threats equal? Associations of childhood exposure to physical attack versus threatened violence with preadolescent brain structure

BackgroundNeurodevelopmental studies of childhood adversity often define threatening experiences as those involving harm or the threat of harm. Whether effects differ between experiences involving harm (“physical attack”) versus the threat of harm alone (“threatened violence”) remains underexplored. We hypothesized that while both types of experiences would be associated with smaller preadolescent global and corticolimbic brain volumes, associations with physical attack would be greater.MethodsGeneration R Study researchers (the Netherlands) acquired T1-weighted scans from 2905 preadolescent children, computed brain volumes using FreeSurfer, and asked mothers whether their children ever experienced physical attack (n = 202) or threatened violence (n = 335). Using standardized global (cortical, subcortical, white matter) and corticolimbic (amygdala, hippocampus, anterior cingulate cortex, orbitofrontal cortex) volumes, we fit confounder-adjusted models.ResultsPhysical attack was associated with smaller global volumes (β_cortical=−0.14; 95% CI: −0.26, −0.02); β_{white matter}= −0.16; 95% CI: − 0.28, − 0.03) and possibly some corticolimbic volumes, e.g., β_{amygdala/ICV-adjusted}= −0.10 (95% CI: −0.21, 0.01). We found no evidence of associations between threatened violence and smaller volumes in any outcome; instead, such estimates were small, highly uncertain, and positive in direction.ConclusionsExperiences of physical attack and threatened violence may have quantitively different neurodevelopmental effects. Thus, differences between types of threatening experiences may be neurodevelopmentally salient.     

Impact of carbidopa-levodopa enteral suspension on quality of life and activities of daily living in patients with advanced Parkinson's disease: Results from a pooled meta-analysis

IntroductionTo estimate the impact of carbidopa/levodopa enteral suspension (CLES) on key patient-centered outcomes in patients with advanced Parkinson's disease (PD).MethodsA comprehensive literature review identified relevant studies, from which data were meta-analyzed over 3-month intervals up to 24 months. Patient-centered outcomes of interest included mean (95% CI) changes from baseline (Δ) in quality of life (QoL), measured using PD-specific (PDQ-8, PDQ-39) and generic (EQ-5D) instruments; activities of daily living (ADL), measured in On and Off states using UPDRS Part II; and motor symptoms (i.e., Off time/day and motor examination [measured in On and Off states using UPDRS Part III]).ResultsThe pooled meta-analysis included data from 26 studies evaluating 1556 patients on CLES. At 3 months, all outcomes showed significant improvement: QoL (ΔPDQ-39 = −10.26 [-11.54, −8.97], ΔEQ-5D_VAS = 15.42 [12.58, 18.26]); ADL (ΔUPDRS II_ON = −4.32 [-5.63, −3.01]); motor symptoms (ΔOff time hours/day = −3.48 [-4.15, −2.82], ΔUPDRS III_ON = −6.20 [-9.88, −2.51]). At 24 months, there were statistically significant mean improvements in QoL (ΔPDQ-39 = −7.74 [-12.40, −3.07], ΔEQ-5D_VAS = 11.18 [6.90, 15.45]) and ADL (ΔUPDRS II_OFF = −3.88 [-5.34, −2.42]), and Off time (−4.21 [-5.16, −3.26] hours/day).ConclusionsImpact of CLES on significantly reducing Off time/day was observed to be rapid and durable (i.e., remained consistent across 24 months). Most QoL and ADL measures showed a consistent pattern of improvement with initiation of treatment and remained significantly improved from baseline at 24 months.     

Gene signatures in peripheral blood immune cells related to insulin resistance and low tyrosine metabolism define a sub-type of depression with high CRP and anhedonia

Inflammation and altered glucose metabolism are two pathways implicated in the pathophysiology of major depressive disorder (MDD). We have previously shown that high inflammation as measured by C-reactive protein (CRP) in MDD patients is associated with symptoms of anhedonia, a core symptom of MDD, along with deficits in dopaminergic reward circuitry. Increased inflammation can shift metabolic demand and reprogram cellular energy sources, which may collectively impact the brain and reward processing to contribute to symptoms of anhedonia. To determine whether immunometabolic gene signatures were enriched in immune cells of depressed patients with increased inflammation and anhedonia, we examined whole-blood gene expression microarray (Illumina HumanHT-12) data from unmedicated, medically-stable patients with MDD (n = 93). Patients were considered to have increased inflammation based on High (>3mg/L) versus Low (≤3mg/L) plasma CRP, and further classified as having a self-reported phenotype of High (n = 30, 33rd percentile) versus Low (n = 32, 67th percentile) Anhedonia. Functional enrichment of gene pathways was assessed by Gene Set Enrichment Analysis (GSEA) using the KEGG pathway database. Pathways related to glucose metabolism (insulin signaling, insulin resistance, HIF-1, PI3K/AKT signaling), cancer (e.g., genes related to insulin and PI3K/AKT signaling), and inflammation (B cell, T cell and Fc receptor signaling) were specifically enriched in patients with both High CRP and High Anhedonia (all FDR q < 0.25). Within patients with High CRP in GSEA, the insulin signaling pathway was the top enriched pathway in patients with High versus Low Anhedonia (n = 10 and 9 respectively), which was driven by genes expressed predominantly in monocytes (z = 2.95, p < 0.01). Conversely, within patients with High Anhedonia, in addition to enrichment of immunometabolic pathways, the tyrosine metabolism pathway was also reduced in patients with High versus Low CRP (n = 20 and 10 respectively). Of note, enrichment of immunometabolic pathways was confirmed in complementary linear regression analyses examining pathways associated with a CRP-by-Anhedonia interaction term while controlling for clinical covariates in all patients (n = 93). These results indicate that increased glucose and low tyrosine metabolism define a subset of depressed patients with high inflammation and anhedonia. Enrichment of cancer-related pathways driven by metabolic genes also suggests a shift in immune cell metabolism from oxidative phosphorylation to glycolysis. Together these data suggest that anhedonia in MDD with high CRP involves both immunometabolic shifts and reduced dopamine precursor availability.     

Interleukin-8 dysregulation is implicated in brain dysmaturation following preterm birth

BackgroundPreterm birth is associated with dysconnectivity of structural brain networks, impaired cognition and psychiatric disease. Systemic inflammation contributes to cerebral dysconnectivity, but the immune mediators driving this association are poorly understood. We analysed information from placenta, umbilical cord and neonatal blood, and brain MRI to determine which immune mediators link perinatal systemic inflammation with dysconnectivity of structural brain networks.MethodsParticipants were 102 preterm infants (mean gestational age 29⁺¹ weeks, range 23⁺³-32⁺⁰). Placental histopathology identified reaction patterns indicative of histologic chorioamnionitis (HCA), and a customized immunoassay of 24 inflammation-associated proteins selected to reflect the neonatal innate and adaptive immune response was performed from umbilical cord (n = 55) and postnatal day 5 blood samples (n = 71). Brain MRI scans were acquired at term-equivalent age (41⁺⁰ weeks [range 38⁺⁰-44⁺⁴ weeks]) and alterations in white matter connectivity were inferred from mean diffusivity and neurite density index across the white matter skeleton.ResultsHCA was associated with elevated concentrations of C5a, C9, CRP, IL-1β, IL-6, IL-8 and MCP-1 in cord blood, and IL-8 concentration predicted HCA with an area under the receiver operator curve of 0.917 (95% CI 0.841 – 0.993, p < 0.001). Fourteen analytes explained 66% of the variance in the postnatal profile (BDNF, C3, C5a, C9, CRP, IL-1β, IL-6, IL-8, IL-18, MCP-1, MIP-1β, MMP-9, RANTES and TNF-α). Of these, IL-8 was associated with altered neurite density index across the white matter skeleton after adjustment for gestational age at birth and at scan (β = 0.221, p = 0.037).ConclusionsThese findings suggest that IL-8 dysregulation has a role in linking perinatal systemic inflammation and atypical white matter development in preterm infants.     

Associations between peripheral inflammation and resting state functional connectivity in adolescents

Relatively little is known about associations between peripheral inflammation and neural function in humans. Neuroimaging studies in adults have suggested that elevated peripheral inflammatory markers are associated with altered resting state functional connectivity (rsFC) in several brain networks associated with mood and cognition. Few studies have examined these associations in adolescents, yet scarce data from adolescents point to different networks than adult studies. The current study examined the associations between peripheral inflammation and rsFC in a community sample of adolescents (n = 70; age, 12–15 years; 32 female, 36 male, 2 nonbinary). After blood sampling, an fMRI scan was performed to assess rsFC. Assay for serum inflammatory markers, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP), was performed. Results indicated that higher TNF-α was associated with altered rsFC between the right amygdala and left striatum and between the right inferior frontal gyrus and left parietal cortex (p < 0.05 whole-brain corrected). Associations with IL-6 and CRP were not significant. In contrast with findings in adults, inflammation may have unique links with the connectivity of the developing adolescent brain. Results have implications for understanding how peripheral inflammation may influence connectivity during adolescence, when neural networks are undergoing major developmental changes.     

Early childhood adversity in adult patients with metastatic lung cancer: Cross-sectional analysis of symptom burden and inflammation

ObjectivePsychological and physical symptoms commonly occur in patients with metastatic lung cancer and are associated with reduced quality of life and decreased survival. Previous work has associated these symptoms with inflammation. The experience of Early Childhood Adversity (ECA) is linked to chronic inflammation and may identify adult cancer patients who are at-risk for psychological and physical symptoms. We thus hypothesized that ECA in lung cancer patients would be associated with increased psychological symptoms (distress, anxiety, and depression) and physical symptoms and that this relationship would be explained by inflammation.MethodsPatients with metastatic lung cancer (n = 92) were evaluated for ECA using the Risky Families Questionnaire. Concomitant assessments were made of distress (Distress Thermometer and Problem List [DT&PL]), anxiety (Generalized Anxiety Disorder-7), depression (Patient Hospital Questionniare-9), physical symptoms (DT&PL), and inflammation (C-reactive protein [CRP]). Multivariate models were created to explain associations of ECA with depression, anxiety, distress, number of physical problems, and inflammation.ResultsECA was associated with distress (r = 0.24, p = .03), anxiety (r = 0.30, p = .004), depression (r = 0.35, p = .001), greater physical problems (r = 0.25, p = .03), younger age (r = -0.29, p = .006), and elevated CRP (r = 0.22, p = .04). Multivariate analyses of outcomes found that depression severity was independently explained by both ECA and inflammation (β = 0.37, p = .001) but not distress or anxiety, while controlling for age and sex. Number of physical problems were also associated with ECA (β = 0.35, p = .004) but not inflammation. The association between ECA and physical problems was not significant after controlling for depression.ConclusionECA is associated with increased depression and physical symptoms independent of inflammation. Moreover, depression appears to mediate the impact of ECA on physical symptoms. ECA may identify patients at risk for psychological and physical symptoms.