Virtual Ontogeny of Cortical Growth Preceding Mental Illness

BACKGROUND

Morphology of the human cerebral cortex differs across psychiatric disorders, with neurobiology and developmental origins mostly undetermined. Deviations in the tangential growth of the cerebral cortex during pre/perinatal periods may be reflected in individual variations in cortical surface area later in life.

METHODS

Interregional profiles of group differences in surface area between cases and controls were generated using T1-weighted magnetic resonance imaging from 27,359 individuals including those with attention-deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, schizophrenia, and high general psychopathology (through the Child Behavior Checklist). Similarity of interregional profiles of group differences in surface area and prenatal cell-specific gene expression was assessed.

RESULTS

Across the 11 cortical regions, group differences in cortical area for attention-deficit/hyperactivity disorder, schizophrenia, and Child Behavior Checklist were dominant in multimodal association cortices. The same interregional profiles were also associated with interregional profiles of (prenatal) gene expression specific to proliferative cells, namely radial glia and intermediate progenitor cells (greater expression, larger difference), as well as differentiated cells, namely excitatory neurons and endothelial and mural cells (greater expression, smaller difference). Finally, these cell types were implicated in known pre/perinatal risk factors for psychosis. Genes coexpressed with radial glia were enriched with genes implicated in congenital abnormalities, birth weight, hypoxia, and starvation. Genes coexpressed with endothelial and mural genes were enriched with genes associated with maternal hypertension and preterm birth.

CONCLUSIONS

Our findings support a neurodevelopmental model of vulnerability to mental illness whereby prenatal risk factors acting through cell-specific processes lead to deviations from typical brain development during pregnancy.

Common and gender-specific associations with cocaine use on gray matter volume: Data from the ENIGMA addiction working group

Gray matter volume (GMV) in frontal cortical and limbic regions is susceptible to cocaine-associated reductions in cocaine-dependent individuals (CD) and is negatively associated with duration of cocaine use. Gender differences in CD individuals have been reported clinically and in the context of neural responses to cue-induced craving and stress reactivity. The variability of GMV in select brain areas between men and women (e.g., limbic regions) underscores the importance of exploring interaction effects between gender and cocaine dependence on brain structure. Therefore, voxel-based morphometry data derived from the ENIGMA Addiction Consortium were used to investigate potential gender differences in GMV in CD individuals compared to matched controls (CTL). T1-weighted MRI scans and clinical data were pooled from seven sites yielding 420 gender- and age-matched participants: CD men (CDM, n = 140); CD women (CDW, n = 70); control men (CTLM, n = 140); and control women (CTLW, n = 70). Differences in GMV were assessed using a 2 × 2 ANCOVA, and voxelwise whole-brain linear regressions were conducted to explore relationships between GMV and duration of cocaine use. All analyses were corrected for age, total intracranial volume, and site. Diagnostic differences were predominantly found in frontal regions (CD < CTL). Interestingly, gender × diagnosis interactions in the left anterior insula and left lingual gyrus were also documented, driven by differences in women (CDW < CTLW). Further, lower right hippocampal GMV was associated with greater cocaine duration in CDM. Given the importance of the anterior insula to interoception and the hippocampus to learning contextual associations, results may point to gender-specific mechanisms in cocaine addiction.

Targeted delivery controlled release of hepatic growth factor and insulin-like growth factor-1 improves left ventricular repair in a porcine model of myocardial ischemia reperfusion injury

Introduction

Nanomedicine offers great potential for treatment of cardiovascular disease. We tested whether direct intramyocardial (IM) injection of pro-angiogenic hepatocyte growth factor (HGF) and pro-myogenic insulin-like growth factor (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) enhances myocardial retention, controlled release and improves myocardial repair in a porcine ischemia-reperfusion model.

Methods

Bioactivity of HGF/IGF, released from AlgS-NP, was determined by cell proliferation assays in vitro. Myocardial infarction (MI) was induced by 75min balloon occlusion of the mid-LAD followed by reperfusion. After 1w, pigs (n=12) with marked LV dysfunction (EF&lt;45%) were randomized to fusion imaging-guided IM injections of 8 mg Cy5-labelled AlgS-NP loaded with 200μg HGF and 200μg IGF-1 (GF) or with phosphate-buffered saline (CON) using the MYOSTAR injection catheter. AlgS-NP retention after IM or intracoronary (IC) injection was determined by measuring Cy5 plasma levels. At 8w, treatment effect was evaluated using in vivo magnetic resonance imaging and coronary physiological measurements, and via post-mortem analysis of myocardial fibrosis and cardiomyocyte circumference.

Results

We confirmed the bioactivity of the AlgS-NP-released GF in C2C12 and HUVEC cell proliferation assays after 72h culture, being similar to the free GF (Fig. A). AlgS-NP retention was tested in a pig model, 1w after MI. Ejection fraction (EF) was 37±5% (range 27–45%) and infarct size (IS)/LVmass 24±6% (range 19–38%). AlgS-NP retention was better after IM delivery than after IC infusion with plasma Cy5 levels at 30 min after treatment indicating 5% systemic leakage for IM vs. 20% for IC. After 8w, IS/LVmass decreased 8% in GF-treated pigs vs. 3% in CON (P=0.03, Fig. B) and was associated with preserved myocardial blood flow during hyperemia in the infarct (P=0.036) and peri-infarct (PI) zones (P=0.008), increased coronary flow reserve (P=0.05) and decreased index of microcirculatory resistance (P=0.02). LVEF significantly increased in GF-treated pigs (+6±2% vs. −1±1% in CON, P=0.02, Fig. C), and was accompanied by significantly reduced fibrosis (P=0.01) and increased hypertrophy of cardiomyocyte (P=0.03) in the PI zone.

Conclusions

IM injection of AlgS-NP-encapsulated HGF and IGF-1 to the ischemic myocardium significantly improves LV repair, and offers the prospect of innovative treatment for patients with refractory ischemic heart disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EuroNanoMed II Figure AFigure B and C

Brain aging in major depressive disorder

Depression and anxiety are common and often comorbid mental health disorders that represent risk factors for aging-related conditions. Brain aging has shown to be more advanced in patients with Major Depressive Disorder (MDD). Here, we extend prior work by investigating multivariate brain aging in patients with MDD and/or anxiety disorders and examine which factors contribute to older appearing brains. Adults aged 18-57 years from the Netherlands Study of Depression and Anxiety underwent structural MRI. A pre-trained brain age prediction model based on >2,000 samples from the ENIGMA consortium was applied to obtain brain-predicted age differences (brain-PAD, predicted brain age minus chronological age) in 65 controls and 220 patients with current MDD and/or anxiety. Brain-PAD estimates were associated with clinical, somatic, lifestyle, and biological factors. After correcting for antidepressant use, brain-PAD was significantly higher in MDD (+2.78 years, Cohen’s d=0.25, 95% CI -0.10-0.60) and anxiety patients (+2.91 years, Cohen’s d=0.27, 95% CI -0.08-0.61), compared to controls. There were no significant associations with lifestyle or biological stress systems. A multivariable model indicated unique contributions of higher severity of somatic depression symptoms (b=4.21 years per unit increase on average sum score) and antidepressant use (-2.53 years) to brain-PAD. Advanced brain aging in patients with MDD and anxiety was most strongly associated with somatic depressive symptomatology. We also present clinically relevant evidence for a potential neuroprotective antidepressant effect on the brain-PAD metric that requires follow-up in future research.

Effect of Methylphenidate on Resting-State Connectivity in Adolescents With a Disruptive Behavior Disorder: A Double-Blind Randomized Placebo-Controlled fMRI Study

Some studies suggest that methylphenidate (MPH) might be an effective treatment for antisocial and aggressive behavior in adolescence. However, little is known about the mechanism of action of MPH in adolescents with this kind of psychopathology. MPH is a dopamine and norepinephrine reuptake inhibitor and thus it is likely to affect dopaminergic mesocorticolimbic pathways. This is the first study to investigate the effect of MPH on resting-state connectivity of three mesolimbic seed regions with the rest of the brain in clinical referred male adolescents with a disruptive behavior disorder (DBD). Thirty-six male DBD adolescents and 31 male healthy controls (HCs) were included. DBD subjects were randomly allocated to a single dose of MPH (DBD-MPH, n = 20) or placebo (DBD-PCB, n = 16). Seed-based resting-state functional connectivity of the nucleus accumbens (NAcc), amygdala, and ventral tegmental area (VTA) with the rest of the brain was compared between groups. The NAcc seed showed increased connectivity in DBD-PCB compared to HC with the occipital cortex, posterior cingulate cortex (PCC), precuneus, and inferior parietal lobule (IPL) and increased connectivity in DBD-PCB compared to DBD-MPH with occipital cortex, IPL, and medial frontal gyrus. The amygdala seed showed increased connectivity in DBD-PCB compared to HC with the precuneus and PCC. The VTA seed showed increased connectivity in the DBD-MPH compared to the DBD-PCB group with a cluster in the postcentral gyrus and a cluster in the supplementary motor cortex/superior frontal gyrus. Both NAcc and amygdala seeds showed no connectivity differences in the DBD-MPH compared to the HC group, indicating that MPH normalizes the increased functional connectivity of mesolimbic seed regions with areas involved in moral decision making, visual processing, and attention.

Clec4e signalling influences left-ventricular functional recovery in a murine model of myocardial ischemia-reperfusion injury

Introduction

The acute inflammatory response contributes substantially to functional recovery and remodelling of the left ventricle after acute ischemic injury. Previously, we have shown that the C-Type Lectin Receptor CLEC4E plays a role in early leukocyte recruitment during the acute inflammatory response of ischemia-reperfusion injury (I/R). However, the role of CLEC4E signalling in functional recovery of the left ventricle after I/R remains unknown. Therefore, we studied the chronic inflammatory response and left-ventricular remodelling in murine gene deletion model of Clec4e, subjected to I/R.

Methods

In anesthetized C57Bl6/J wild-type (n=14) and Clec4e−/− (n=13) mice, we transiently occluded the left-descending artery for 60 min, followed by 4 weeks reperfusion (I/R). A blood sample was collected at 90 minutes reperfusion to measure high-sensitivity troponin I (TnI) levels, as a surrogate marker of cardiac damage. At 4 weeks, mice underwent MRI (7T) to investigate the effect of Clec4e-gene deletion on LV-remodelling.

Results

Plasma TnI-levels showed no statistical difference between both groups, indicating that the initial insult was comparable. In wild-type mice, plasma TnI-levels negatively correlated with ejection fraction (EF, R2=0.92 p&lt;0.0001) at 4 weeks I/R, while Clec4e−/− mice showed preserved EF, irrespective of 90 minutes TnI-levels. MRI-analysis at 4 weeks after I/R showed significantly smaller end-diastolic and end-systolic volumes in Clec4e−/− mice, together with a trend towards a higher ejection fraction, suggesting better preserved structural and functional LV-remodelling (Fig.1).

Conclusion

The inflammatory leukocyte-associated Clec4e signalling pathway impairs functional recovery of the left ventricle after myocardial I/R injury. Inhibition of the Clec4e receptor may be a promising strategy in the treatment of ischemic injury.

Figure 1

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Scholarship Ir. Jozef en Mevr. Reinhilde De Swerts 2018-2022 by the Royal Academy of Medicine of Belgium

Nanoparticles loaded with hepatic growth factor and insulin-like growth factor-1 improve left ventricular repair in a porcine model of myocardial Ischemia reperfusion injury

Introduction

Nanomedicine offers great potential for treatment of cardiovascular disease. We tested whether intramyocardial (IM) injection of pro-angiogenic hepatocyte growth factor (HGF) and anti-apoptotic, pro-myogenic insulin-like growth factor 1 (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) improves left ventricular (LV) functional recovery in a porcine ischemia-reperfusion (I/R) model.

Methods

Myocardial infarction (MI) was induced by 75min balloon occlusion of the mid-LAD followed by reperfusion. After 1w, pigs (n=12) with marked LV dysfunction (EF&lt;45%) were randomized to fusion imaging-guided IM injections of 8 mg Cy5-labelled AlgS-NP loaded with 200μg HGF and IGF-1 (GF) or with phosphate-buffered saline (CON) using the MYOSTAR injection catheter. AlgS-NP retention in the heart was determined by measuring Cy5 levels in peripheral blood. At 8w, treatment effect was evaluated using cardiac magnetic resonance imaging and coronary flow reserve (CFR) measurements, and further assessed using sirius red staining to measure myocardial fibrosis.

Results

At 1w after MI, LV ejection frqction (LVEF) was 37±5% (range 27–45%) and infarct size (IS)/LV mass 24±6% (range 19–38%). Myocardial retention of AlgS-NP was comparable between 2 groups (maximal systemic leakage after IM injection: 9% CON vs 20% GF, P=0.25). After 8 w, IS/LV mass decreased by one third in GF-treated pigs compared with 14% in CON (P=0.03, Fig. A) and was associated with a trend towards improvement in CFR (P=0.05, Fig. B). LVEF significantly increased in GF-treated pigs (6±2% vs. −1±1%, P=0.02, Fig. C), which was attributable to a greater reduction in end-systolic volume. The improvement in LVEF was also consistent with significant reduction of fibrosis (P=0.01, Fig. D) in the peri-infarct zone (PI).

Conclusions

Intramyocardial injection of AlgS-nanoparticle-encapsulated HGF and IGF-1 to the ischemic myocardium significantly improves LV repair, and offers the prospect of innovative treatment for patients with refractory ischemic heart disease.

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): EuroNanoMed, Horizon 2020

Predicting alcohol dependence from multi-site brain structural measures

To identify neuroimaging biomarkers of alcohol dependence (AD) from structural magnetic resonance imaging, it may be useful to develop classification models that are explicitly generalizable to unseen sites and populations. This problem was explored in a mega‐analysis of previously published datasets from 2,034 AD and comparison participants spanning 27 sites curated by the ENIGMA Addiction Working Group. Data were grouped into a training set used for internal validation including 1,652 participants (692 AD, 24 sites), and a test set used for external validation with 382 participants (146 AD, 3 sites). An exploratory data analysis was first conducted, followed by an evolutionary search based feature selection to site generalizable and high performing subsets of brain measurements. Exploratory data analysis revealed that inclusion of case‐ and control‐only sites led to the inadvertent learning of site‐effects. Cross validation methods that do not properly account for site can drastically overestimate results. Evolutionary‐based feature selection leveraging leave‐one‐site‐out cross‐validation, to combat unintentional learning, identified cortical thickness in the left superior frontal gyrus and right lateral orbitofrontal cortex, cortical surface area in the right transverse temporal gyrus, and left putamen volume as final features. Ridge regression restricted to these features yielded a test‐set area under the receiver operating characteristic curve of 0.768. These findings evaluate strategies for handling multi‐site data with varied underlying class distributions and identify potential biomarkers for individuals with current AD.

Mega-Analysis of Gray Matter Volume in Substance Dependence: General and Substance-Specific Regional Effects

OBJECTIVE

Although lower brain volume has been routinely observed in individuals with substance dependence compared with nondependent control subjects, the brain regions exhibiting lower volume have not been consistent across studies. In addition, it is not clear whether a common set of regions are involved in substance dependence regardless of the substance used or whether some brain volume effects are substance specific. Resolution of these issues may contribute to the identification of clinically relevant imaging biomarkers. Using pooled data from 14 countries, the authors sought to identify general and substance-specific associations between dependence and regional brain volumes.

METHOD

Brain structure was examined in a mega-analysis of previously published data pooled from 23 laboratories, including 3,240 individuals, 2,140 of whom had substance dependence on one of five substances: alcohol, nicotine, cocaine, methamphetamine, or cannabis. Subcortical volume and cortical thickness in regions defined by FreeSurfer were compared with nondependent control subjects when all sampled substance categories were combined, as well as separately, while controlling for age, sex, imaging site, and total intracranial volume. Because of extensive associations with alcohol dependence, a secondary contrast was also performed for dependence on all substances except alcohol. An optimized split-half strategy was used to assess the reliability of the findings.

RESULTS

Lower volume or thickness was observed in many brain regions in individuals with substance dependence. The greatest effects were associated with alcohol use disorder. A set of affected regions related to dependence in general, regardless of the substance, included the insula and the medial orbitofrontal cortex. Furthermore, a support vector machine multivariate classification of regional brain volumes successfully classified individuals with substance dependence on alcohol or nicotine relative to nondependent control subjects.

CONCLUSIONS

The results indicate that dependence on a range of different substances shares a common neural substrate and that differential patterns of regional volume could serve as useful biomarkers of dependence on alcohol and nicotine.

Machine Learning for Large-Scale Quality Control of 3D Shape Models in Neuroimaging

As very large studies of complex neuroimaging phenotypes become more common, human quality assessment of MRI-derived data remains one of the last major bottlenecks. Few attempts have so far been made to address this issue with machine learning. In this work, we optimize predictive models of quality for meshes representing deep brain structure shapes. We use standard vertex-wise and global shape features computed homologously across 19 cohorts and over 7500 human-rated subjects, training kernelized Support Vector Machine and Gradient Boosted Decision Trees classifiers to detect meshes of failing quality. Our models generalize across datasets and diseases, reducing human workload by 30-70%, or equivalently hundreds of human rater hours for datasets of comparable size, with recall rates approaching inter-rater reliability.

Neurostimulation in alcohol dependence: The effect of repetitive transcranial magnetic stimulation on brain function and craving

Background

Alcohol dependence has long been related to impaired processing and handling of negative emotions. This is the first study to compare emotion regulation (ER) at a behavioral and neural level in alcohol dependent patients (ADPs) and healthy controls (HCs). It also examines the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) on ER abilities and related craving levels in ADPs.

Method

Thirty-six ADPs and 32 HCs matched on age, sex, and education, were included in a within-subject fixed-order study with one functional magnetic resonance imaging (fMRI) session and one rTMS plus fMRI session, with high-frequency (10 Hz) rTMS over the right dorsolateral prefrontal cortex (dlPFC). An fMRI emotion regulation task (ERT) was administered during both sessions and craving was measured before and after each ERT.

Results

ADPs were impaired in the regulation of negative emotion and showed a higher activation of ER related brain areas compared to HCs. Furthermore, active rTMS improved ER abilities in both ADPs and HCs, but was accompanied by a decrease in anterior cingulate and left dlPFC activity only in ADPs. In addition, the ERT-induced increase in craving levels in ADPs was trend-significantly reduced by active rTMS, with a large effect size.

Conclusions

ADPs are impaired in the regulation of negative emotion and show enhanced neural activity in the ER brain circuit. High-frequency rTMS improves ER in ADPs and HCs and normalizes neural activity and tends to reduce craving in ADPs. Future studies are needed to test the long-term effects of (multiple session) rTMS on ER, craving, and drinking.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

IDENTIFYING PANIC DISORDER SUBTYPES USING FACTOR MIXTURE MODELING

BACKGROUND

The clinical presentation of panic disorder (PD) is known to be highly heterogeneous, complicating research on its etiology, neurobiological pathways, and treatment. None of the attempts to identify PD subtypes have been independently reproduced, rendering the current literature inconclusive.

METHODS

Using a data-driven, case-centered approach (factor mixture modeling) on a broad range of anxiety symptoms assessed with the Beck anxiety inventory, the present study identifies PD disorder subtypes in a large (n = 658), well-documented mixed-population sample from the Netherlands Study of Depression and Anxiety (NESDA), with subtypes being validated and detailed using a variety of clinical characteristics.

RESULTS

A three-class, one-factor model proved superior to all other possible models (Bayesian information criterion = 13,200; Lo-Mendel-Rubin = 0.0295; bootstrapped likelihood ratio test ≤ 0.0001), with the first class, a cognitive-autonomic subtype, accounting for 29.8%, the second class, the autonomic subtype, for 29.9%, and a third class, the aspecific subtype, for 40.3% of the population. The cognitive-autonomic and autonomic subtypes showed significant differences compared to the aspecific subtype (e.g., comorbidity and suicide attempts) but on severity differed between themselves only.

CONCLUSION

Three qualitatively different PD subtypes were identified: a severe cognitive-autonomic subtype, a moderate autonomic subtype, and a mild aspecific subtype. Qualitative and quantitative differences were related to severity and clinical properties such as comorbidity, suicide attempts, sleep, and sense of mastery.

The revised dopamine hypothesis of schizophrenia: evidence from pharmacological MRI studies with atypical antipsychotic medication

The revised dopamine (DA) hypothesis states that clinical symptoms of schizophrenia are caused by an imbalance of the DA system. In this article, we aim to review evidence for this hypothesis by evaluating functional magnetic resonance imaging studies in schizophrenia. Because atypical drugs are thought to have a normalizing effect on DA neurotransmission, we have focused on pharmacological MRI (PhMRI) studies that explore the effect of these drugs on prefrontal and striatal brain activity in schizophrenia patients. We encountered a total of 13 studies, most of which reported enhanced prefrontal activity associated with alleviation of negative symptoms and improvement of cognitive functions, following treatment with atypical antipsychotics. Besides increasing prefrontal cortex activity, atypical antipsychotics have also shown to be effective in the regulation of striatal functioning. The current PhMRI findings support the revised DA hypothesis of schizophrenia by confirming hypoactivity of the prefrontal cortex in schizophrenia and, following atypical antipsychotics, improvement of prefrontal and subcortical functions reflecting enhanced DA activity.