Development of a Gut-On-A-Chip Model for High Throughput Disease Modeling and Drug Discovery.

A common bottleneck in any drug development process is finding sufficiently accurate models that capture key aspects of disease development and progression. Conventional drug screening models often rely on simple 2D culture systems that fail to recapitulate the complexity of the organ situation. In this study, we show the application of a robust high throughput 3D gut-on-a-chip model for investigating hallmarks of inflammatory bowel disease (IBD). Using the OrganoPlate platform, we subjected enterocyte-like cells to an immune-relevant inflammatory trigger in order to recapitulate key events of IBD and to further investigate the suitability of this model for compound discovery and target validation activities. The induction of inflammatory conditions caused a loss of barrier function of the intestinal epithelium and its activation by increased cytokine production, two events observed in IBD physiopathology. More importantly, anti-inflammatory compound exposure prevented the loss of barrier function and the increased cytokine release. Furthermore, knockdown of key inflammatory regulators RELA and MYD88 through on-chip adenoviral shRNA transduction alleviated IBD phenotype by decreasing cytokine production. In summary, we demonstrate the routine use of a gut-on-a-chip platform for disease-specific aspects modeling. The approach can be used for larger scale disease modeling, target validation and drug discovery purposes.

Long-term cognitive and cardiac outcomes after prenatal exposure to chemotherapy in children aged 18 months or older: an observational study.

BACKGROUND: Chemotherapy for the treatment of maternal cancers during pregnancy has become more acceptable in the past decade; however, the effect of prenatal exposure to chemotherapy on cardiac and neurodevelopmental outcomes of the offspring is still uncertain. We aimed to record the general health, cardiac function, and neurodevelopmental outcomes of children who were prenatally exposed to chemotherapy. METHODS: We did an interim analysis of a multicentre observational cohort study assessing children who were prenatally exposed to maternal cancer staging and treatment, including chemotherapy. We assessed children at birth, at age 18 months, and at age 5-6, 8-9, 11-12, 14-15, or 18 years. We did clinical neurological examinations, tests of the general level of cognitive functioning (Bayley or intelligence quotient [IQ] test), electrocardiography and echocardiography, and administered a questionnaire on general health and development. From age 5 years, we also did audiometry, the Auditory Verbal Learning Test, and subtasks of the Children's Memory Scale, and the Test of Everyday Attention for Children, and we also completed the Child Behavior Checklist. This study is registered with ClinicalTrials.gov, number NCT00330447. FINDINGS: 236 cycles of chemotherapy were administered in 68 pregnancies. We assessed 70 children, born at a median gestational age of 35·7 weeks (range 28·3-41·0; IQR 3·3; 47 women at <37 weeks), with a median follow-up period of 22·3 months (range 16·8-211·6; IQR 54·9). Although neurocognitive outcomes were within normal ranges, cognitive development scores were lower for children who were born preterm than for those born at full term. When controlling for age, sex, and country, the score for IQ increased by an average 11·6 points (95% CI 6·0-17·1) for each additional month of gestation (p<0·0001). Our measurements of the children's behaviour, general health, hearing, and growth corresponded with those of the general population. Cardiac dimensions and functions were within normal ranges. We identified a severe neurodevelopmental delay in both members of one twin pregnancy. INTERPRETATION: Fetal exposure to chemotherapy was not associated with increased CNS, cardiac or auditory morbidity, or with impairments to general health and growth compared with the general population. However, subtle changes in cardiac and neurocognitive measurements emphasise the need for longer follow-up. Prematurity was common and was associated with impaired cognitive development. Therefore, iatrogenic preterm delivery should be avoided when possible. FUNDING: Research Foundation-Flanders; Research Fund-K U Leuven; Agency for Innovation by Science and Technology; Stichting tegen Kanker; Clinical Research Fund-University Hospitals Leuven; and Belgian Cancer Plan, Ministery of Health.

Validation of ICA as a tool to remove eye movement artifacts from EEG/ERP.

Eye movement artifacts in electroencephalogram (EEG) recordings can greatly distort grand mean event-related potential (ERP) waveforms. Different techniques have been suggested to remove these artifacts prior to ERP analysis. Independent component analysis (ICA) is suggested as an alternative method to "filter" eye movement artifacts out of the EEG, preserving the brain activity of interest and preserving all trials. However, the identification of artifact components is not always straightforward. Here, we compared eye movement artifact removal by ICA compiled on 10 s of EEG, on eye movement epochs, or on the complete EEG recording to the removal of eye movement artifacts by rejecting trials or by the Gratton and Coles method. ICA performed as well as the Gratton and Coles method. By selecting only eye movement epochs for ICA compilation, we were able to facilitate the identification of components representing eye movement artifacts.

Are children with ADHD predominantly inattentive and combined subtypes different in terms of aspects of everyday attention?

The validity of the DSM-IV subtypes is a recurring diagnostic debate in attention deficit/hyperactivity disorder (ADHD). Laboratory measures, such as the test of everyday attention for children (TEA-Ch) can help us address this question. TEA-Ch is a test battery covering different aspects of everyday attention relating to selective and sustained attention and attentional control. The aim of the current study was to investigate whether this instrument can differentiate between combined (ADHD-C) and inattentive subtype (ADHD-I) of ADHD. Subjects were recruited from a multidisciplinary ADHD outpatient unit and tested free of medication. Sixty-four children with a diagnosis of ADHD were included (38 with ADHD-C; 26 with ADHD-I). The control group was 76 children recruited from primary and secondary schools. Children with ADHD performed worse than controls on 6 out of 9 TEA-Ch subtests. However a regression analysis revealed that TEA-Ch subtests made only a marginal contribution to the correct classification of ADHD, once the effects of IQ and age are controlled. Confirmatory factor analysis in our ADHD group demonstrated that the three factor structure achieved a poor fit. More detailed analysis suggested that inferior performance on the tasks designed to test vigilance was not the result of deficient-sustained attention. ADHD-C and ADHD-I showed very few differences across tasks. In conclusion, our results provided not much support for the value of the ADHD-C and ADHD-I distinction in predicting difficulties in everyday attention.

Hippocampal malrotation in pediatric patients with epilepsy associated with complex prefrontal dysfunction.

PURPOSE: The cognitive consequences of hippocampal malrotation (HIMAL) were investigated in a matched control study of children with epilepsy. METHODS: Seven children with HIMAL were compared on a range of memory and attention tasks with 21 control children with epilepsy without temporal role pathology and 7 children with epilepsy and magnetic resonance imaging (MRI)-documented hippocampal sclerosis. In addition, in a statistical morphometric analysis, MRI studies from four children with HIMAL were compared to similar images of 20 age-matched typically developing control children. RESULTS: Although the task battery was sensitive to the memory deficit of the children with hippocampal sclerosis, it did not reveal memory impairment in the patients with HIMAL. In contrast, the patients with HIMAL were impaired on the attentionally more demanding dual tasks, compared to both the control and the hippocampal sclerosis group. The structural MRI analysis revealed morphometric abnormalities in the tail of the affected hippocampus, the adjacent neocortex, and the ipsilateral medial thalamus. The basal forebrain was bilaterally affected. Abnormalities in remote cortex were found in the ipsilateral temporal lobe, the contralateral anterior cingulate gyrus, and bilateral in the dorsolateral and lateral-orbitofrontal prefrontal cortex. DISCUSSION: Because the prefrontal cortical regions have been shown to be active during dual-task performance, the MRI results converge with the neuropsychological findings of impairment on these tasks. We conclude that HIMAL had no direct memory repercussions, but was secondary to subtle but widespread neurologic abnormalities that also affected morphology and functioning of the prefrontal cortex.

Working memory in children with epilepsy: an event-related potentials study.

PURPOSE: The aim of this study was to find out whether children with idiopathic epilepsy did show different cortical activation patterns compared to non-epileptic children during performance of a working memory task. To this end event-related potentials (ERPs) were measured during a visual 1-backmatching task. A quantitative analysis technique to analyze the ERP data, without any 'a priori' decisions on 'peak' presence, amplitudes or latencies, is used. METHODS: 46 children were tested (6-16 years old): 21 children with well-controlled "benign" epilepsy (benign rolandic epilepsy, n=9, idiopathic generalized epilepsy, n=12) and a control group of 25 non-epileptic children. Behavioral task performance and ERPs following both target and nontarget stimuli were compared across both study groups. RESULTS: No differences were found in the number of omission errors or commission errors or in the reaction times between groups. However, ERPs following target stimuli showed significantly higher amplitude in the epilepsy group compared to the control group over frontal and central regions within the time window between 250 and 425 ms poststimulus, what coincides with the time window of target-nontarget stimulus discrimination. DISCUSSION: Our study shows that children with benign, well-controlled epilepsy show a different cortical activation pattern during a visual working memory task. We hypothesize that they need more brain processing effort to achieve the same performance level as their age matched controls.

ERP correlates of complex human decision making in a gambling paradigm: detection and resolution of conflict.

The present event-related potential study investigated the correlates of decision making in relation to the amount of response conflict. In a gambling paradigm, response conflict was introduced by giving participants the option to either gamble or pass. Second, the odds and gains in each trial were manipulated to make the decision to gamble or pass determined or underdetermined. Underdetermined trials included an extra conflict. The N2 was modulated by the mere presence of conflict. In contrast to both conflict monitoring and inhibition theories for N2, these results suggest that an enhancement in N2 reflects the mere detection of conflicting alternatives. The P3 showed a fronto-central increase in amplitude in trials including two forms of response conflict compared to trials including only one conflict. These findings suggest that P3 reflects part of the conflict resolution processes.

Specific memory impairment in a multiple disabled male with fragile X syndrome and temporal lobe epilepsy.

Evaluation of the cognitive repercussions of an epileptic disorder and its treatment are important issues in clinical follow-up. This especially holds true for temporal lobe epilepsy (TLE) where resective surgery can be a valid treatment option. However, in patients where TLE coexists with another neurocognitive disorder, questions can arise about the precise nature of the neuropsychological deficits. The aim of the present study was to evaluate memory impairments, found in a male aged 12 years who had the dual pathology of fragile X syndrome and refractory TLE. Memory functions of this child were compared with those of a male aged 11 years 7 months with fragile X syndrome matched for intellectual functioning as indicated by highly comparable verbal (5 y 5 mo vs 5 y 9 mo) and non-verbal (7 y 2 mo vs 6 y 1 mo) cognitive age equivalents. Performance on each neuropsychological measure was evaluated twice, separately with normative data based on chronological age and on verbal or non-verbal cognitive level. A specific, distinguishable profile of task performance could be found only when controlling for general level of cognitive functioning. This made it possible to accurately evaluate neuropsychological abilities before and 6 months after anterior temporal lobe resection even in this male with a complex neurological pathology.