Impaired migration of autologous induced neural stem cells from patients with schizophrenia and implications for genetic risk for psychosis

Stem cell technologies have presented explicit evidence of the neurodevelopmental hypothesis of schizophrenia. However, few studies investigated relevance of the schizophrenia genetic liability and the use of genetic reprogramming on pluripotent stem cells to the impaired neurodevelopment shown by stem cells. Therefore, this study sought to investigate the cellular phenotypes of induced neural stem cells (iNSCs) derived without genetic modification from patients with schizophrenia and from genetic high risk (GHR) individuals. Three patients with a diagnosis of schizophrenia, 3 GHR individuals who had two or more relatives with schizophrenia, and 3 healthy volunteers participated. iNSCs were derived using a small molecule-based lineage switch method, and their gene expression levels and migration capabilities were examined. Demographic characteristics were not different among the groups (age, χ² = 5.637, P = .060; education, χ² = 2.111, P = .348). All participants stayed well during the follow-up except one GHR individual who developed psychosis 1.5 years later. Migration capacity was impaired in iNSCs from patients with schizophrenia (SZ-iNSCs) compared to iNSCs from GHR individuals or controls (P < .001). iNSCs from a GHR individual who later developed schizophrenia showed migratory impairment that was similar to SZ-iNSCs. Gene expression levels of Sox2 in SZ-iNSCs were significantly lower than those in controls (P = .028). Defective migration in genetically unmodified SZ-iNSCs is the first direct demonstration of neurodevelopmental abnormalities in schizophrenia. Additionally, alterations in gene expression in SZ-iNSCs suggest mechanisms by which genetic liability leads to aberrant neurodevelopment.

Cortical Volumetric Correlates of Childhood Trauma, Anxiety, and Impulsivity in Bipolar Disorder

OBJECTIVE

More recently, attention has turned to the linkage between childhood trauma and emotional dysregulation, but the evidence in bipolar disorder (BD) is limited. To determine neurobiological relationships between childhood trauma, current anxiety, and impulsivity, we investigated cortical volumetric correlates of these clinical factors in BD.

METHODS

We studied 36 patients with DSM-5 BD and 29 healthy controls. Childhood trauma, coexisting anxiety, and impulsivity were evaluated with the Korean version-Childhood Trauma Questionnaire (CTQ), the Korean version-Beck Anxiety Inventory (BAI), and the Korean version-Barratt Impulsiveness Scale (BIS). Voxel-based morphometry (VBM) was used to assess gray matter volume (GMV) alterations on the brain magnetic resonance imaging (MRI). Partial correlation analyses were conducted to examine associations between the GMV and each scale in the BD group.

RESULTS

Childhood trauma, anxiety, and impulsivity were interrelated in BD. BD patients revealed significant inverse correlations between the GMV in the right precentral gyrus and CTQ scores (r=-0.609, p<0.0003); between the GMV in the left middle frontal gyrus and BAI scores (r=-0.363, p=0.044). Moreover, patients showed similar tendency of negative correlations between the GMV in the right precentral gyrus and BIS scores; between the GMV in the left middle frontal gyrus and CTQ scores.

CONCLUSION

The present study provides evidence for a neural basis between childhood trauma and affect regulations in BD. The GMV alterations in multiple frontal lobe areas may represent neurobiological markers for anticipating the course of BD.

Early referral and comorbidity as possible causes of the declining transition rate in subjects at clinical high risk for psychosis

AIM

A clinical high risk (CHR) for psychosis is regarded as the state of being at risk of developing psychosis. However, the rate of transition to psychosis among CHR subjects has been declining over time. We aimed to investigate the effects of the possible causes of the declining transition rate.

METHODS

A total of 129 CHR subjects were divided into two groups according to the date of enrollment: the 2005-2009 group and the 2009-2013 group. Baseline demographic and clinical characteristics, including medication prescription, were compared. The duration of untreated prodromal positive symptoms (DUPP) was used to account for early referral.

RESULTS

The transition rate to psychosis in the 2009-2013 group was significantly lower than that in the 2005-2009 group (χ²  = 4.664, P = 0.031), although the risk factors of transition, intelligence quotient and prodromal positive symptoms did not differ between the two groups. When the DUPP was added to the follow-up duration, the between-group difference in the transition rates was no longer significant; however, the P-value was low (χ²  = 2.761, P = 0.097). After adjusting for axis II comorbidities other than schizotypal personality disorder, the effect of group division on the transition rate disappeared; however, the P-value was also low (P = 0.072). The mean olanzapine equivalent dose and the proportion of subjects prescribed with antidepressant or anxiolytic did not differ between the two groups.

CONCLUSIONS

Early referral and axis II comorbidities other than schizotypal personality disorder were associated with the declining transition rate.

Diagnostic value of structural and diffusion imaging measures in schizophrenia

Objectives

Many studies have attempted to discriminate patients with schizophrenia from healthy controls by machine learning using structural or functional MRI. We included both structural and diffusion MRI (dMRI) and performed random forest (RF) and support vector machine (SVM) in this study.

Methods

We evaluated the performance of classifying schizophrenia using RF method and SVM with 504 features (volume and/or fractional anisotropy and trace) from 184 brain regions. We enrolled 47 patients and 23 age- and sex-matched healthy controls and resampled our data into a balanced dataset using a Synthetic Minority Oversampling Technique method. We randomly permuted the classification of all participants as a patient or healthy control 100 times and ran the RF and SVM with leave one out cross validation for each permutation. We then compared the sensitivity and specificity of the original dataset and the permuted dataset.

Results

Classification using RF with 504 features showed a significantly higher rate of performance compared to classification by chance: sensitivity (87.6% vs. 47.0%) and specificity (95.9 vs. 48.4%) performed by RF, sensitivity (89.5% vs. 48.0%) and specificity (94.5% vs. 47.1%) performed by SVM.

Conclusions

Machine learning using RF and SVM with both volume and diffusion measures can discriminate patients with schizophrenia with a high degree of performance. Further replications are required.

Abnormal asymmetry of white matter tracts between ventral posterior cingulate cortex and middle temporal gyrus in recent-onset schizophrenia

INTRODUCTION

Previous studies have reported abnormalities in the ventral posterior cingulate cortex (vPCC) and middle temporal gyrus (MTG) in schizophrenia patients. However, it remains unclear whether the white matter tracts connecting these structures are impaired in schizophrenia. Our study investigated the integrity of these white matter tracts (vPCC-MTG tract) and their asymmetry (left versus right side) in patients with recent onset schizophrenia.

METHOD

Forty-seven patients and 24 age-and sex-matched healthy controls were enrolled in this study. We extracted left and right vPCC-MTG tract on each side from T1W and diffusion MRI (dMRI) at 3T. We then calculated the asymmetry index of diffusion measures of vPCC-MTG tracts as well as volume and thickness of vPCC and MTG using the formula: 2×(right-left)/(right+left). We compared asymmetry indices between patients and controls and evaluated their correlations with the severity of psychiatric symptoms and cognition in patients using the Positive and Negative Syndrome Scale (PANSS), video-based social cognition scale (VISC) and the Wechsler Adult Intelligence Scale (WAIS-III).

RESULTS

Asymmetry of fractional anisotropy (FA) and radial diffusivity (RD) in the vPCC-MTG tract, while present in healthy controls, was not evident in schizophrenia patients. Also, we observed that patients, not healthy controls, had a significant FA decrease and RD increase in the left vPCC-MTG tract. There was no significant association between the asymmetry indices of dMRI measures and IQ, VISC, or PANSS scores in schizophrenia.

CONCLUSION

Disruption of asymmetry of the vPCC-MTG tract in schizophrenia may contribute to the pathophysiology of schizophrenia.

Individualized covariance profile of cortical morphology for auditory hallucinations in first-episode psychosis

Neocortical phenotype of cortical surface area (CSA) and thickness (CT) are influenced by distinctive genetic factors and undergo differential developmental trajectories, which could be captured using the individualized cortical structural covariance (ISC). Disturbed patterns of neocortical development and maturation underlie the perceptual disturbance of psychosis including auditory hallucination (AH). To demonstrate the utility of selected ISC features as primal biomarker of AH in first-episode psychosis (FEP) subjects experiencing AH (FEP-AH), we employed herein a support vector machine (SVM). A total of 147 subjects (FEP-AH, n = 27; FEP-NAH, n = 24; HC, n = 96) underwent T1 -weighted magnetic resonance imaging at 3T. The FreeSurfer software suite was used for cortical parcellation, with the CSA-ISC and CT-ISC then calculated. The most informative ISCs showing statistical significance (P < 0.001) across every run of leave-one-out group-comparison were aligned according to the absolute value of averaged t-statistics and were packaged into candidate feature sets for classification analysis using the SVM. An optimal feature set comprising three CSA-ISCs, including the intraparietal sulcus, Broca's complex, and the anterior insula, distinguished FEP-AH from FEP-NAH subjects with 83.6% accuracy (sensitivity = 82.8%; specificity = 85.7%). Furthermore, six CT-ISCs encompassing the executive control network and Wernicke's module classified FEP-AH from FEP-NAH subjects with 82.3% accuracy (sensitivity = 79.5%; specificity = 88.6%). Finally, extended sets of ISCs related to the default-mode network distinguished FEP-AH or FEP-NAH from HC subjects with 89.0-93.0% accuracy (sensitivity = 88.4-93.4%; specificity = 89.0-94.1%). This study established a distinctive intermediate phenotype of biological proneness for AH in FEP using CSA-ISCs as well as a state marker of disease progression using CT-ISCs.

MRI study of the cavum septum pellucidum in obsessive-compulsive disorder

The cavum septum pellucidum (CSP), a putative marker of neurodevelopmental anomaly, has been associated with an increased risk of several psychiatric disorders. The purpose of this study was to evaluate the CSP in patients with obsessive-compulsive disorder (OCD) compared with healthy control subjects. Seventy-one patients with OCD and 71 healthy volunteers matched for age and sex were evaluated with magnetic resonance imaging. We evaluated the CSP using criteria employed in previous studies: presence of the CSP, length of the CSP, and overall size of the CSP, measured in five grades, ranging from grades 0 (no CSP) to 4 (severe CSP). We evaluated OCD symptom severity using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). The CSP presence was significantly greater in the OCD group (60.6%) than in control subjects (29.6%), and CSP size grade was significantly larger in the OCD group (chi(2) = 15.609, P = 0.004). CSP length showed no significant group difference. Among patients with OCD, those with a CSP had higher scores on the obsession subscale of the Y-BOCS than those without a CSP (Z = -2.358, P = 0.018), while they did not show significant difference from those without a CSP in the compulsion subscale of the Y-BOCS, age, duration of illness, or age at onset. These results indicate that neurodevelopmental alterations in midline structures might contribute to the pathogenesis of OCD.

Gender difference in the prodromal symptoms of first-episode schizophrenia

To investigate the gender difference of early symptoms appearing before the onset of the psychotic symptoms in patients with first-episode schizophrenia, we reviewed the medical records of 63 patients (38 males, 25 females), who were hospitalized for first-episode schizophrenia. The frequency and duration of prodromal and psychotic symptoms, Clinical Global Impression scale scores, Global Assessment of Functioning (GAF) scale scores at admission, and other clinical characteristics were recorded for all patients. Overall, the most common prodromal symptoms were attenuated positive symptoms (89%), followed by mood symptoms (86%). Negative symptoms were the most common in male patients (97.4%), whereas attenuated positive symptoms were the most common in female patients (84%). Male patients demonstrated more frequent negative, cognitive, and obsessive-compulsive symptoms than female patients did and also showed a tendency of having negative symptoms for the longer period. Correlational analysis showed a significant negative correlation between the duration of negative symptoms and GAF scores at admission in male patients. Our findings suggest that different patterns of prodromal symptoms between male and female begin before the onset of the psychosis. Further prospective studies should be needed.

Cavum septum pellucidum in subjects at ultra-high risk for psychosis: compared with first-degree relatives of patients with schizophrenia and healthy volunteers

OBJECTIVE

The cavum septum pellucidum (CSP) is a space between the two leaflets of the septum pellucidum, and is a putative marker of disturbance in early brain development. We examined whether CSP was present more frequently in subjects at ultra-high risk (UHR) for psychosis compared to first-degree relatives of patients with schizophrenia (genetic high risk, GHR) and healthy controls (HC).

METHODS

We evaluated CSP in 87 subjects (30 UHR, 23 GHR, and 34 HC) according to a published grading system using high-resolution magnetic resonance imaging (MRI) with 0.45-mm slice thickness. We also assessed two other criteria: presence of CSP on at least one MRI slice, and abnormally large CSP (i.e., > or =6 mm in length). Correlational analysis between CSP measures and clinical symptoms was also examined.

RESULTS

Based on the grading scale, the UHR group exhibited a significantly higher incidence of abnormal CSP (grades 2, 3, and 4) compared to the HC group, but there were no significant differences in the incidence of abnormal CSP between the UHR and GHR or the GHR and HC groups. There were no significant differences among the groups in the presence of CSP on at least one MRI slice or abnormally large CSP based on the length of CSP. In addition, no significant correlations between CSP measures and clinical symptoms were found.

CONCLUSION

These findings suggest that abnormal CSP might be associated with susceptibility to psychosis, although the CSP itself might be a normal anatomical variant. Further studies using a larger sample are needed to clarify issues on neurodevelopmental perspective in subjects at high risk for psychosis.