Modulation of defensive reactivity by GLRB allelic variation: converging evidence from an intermediate phenotype approach

Representing a phylogenetically old and very basic mechanism of inhibitory neurotransmission, glycine receptors have been implicated in the modulation of behavioral components underlying defensive responding toward threat. As one of the first findings being confirmed by genome-wide association studies for the phenotype of panic disorder and agoraphobia, allelic variation in a gene coding for the glycine receptor beta subunit (GLRB) has recently been associated with increased neural fear network activation and enhanced acoustic startle reflexes. On the basis of two independent healthy control samples, we here aimed to further explore the functional significance of the GLRB genotype (rs7688285) by employing an intermediate phenotype approach. We focused on the phenotype of defensive system reactivity across the levels of brain function, structure, and physiology. Converging evidence across both samples was found for increased neurofunctional activation in the (anterior) insular cortex in GLRB risk allele carriers and altered fear conditioning as a function of genotype. The robustness of GLRB effects is demonstrated by consistent findings across different experimental fear conditioning paradigms and recording sites. Altogether, findings provide translational evidence for glycine neurotransmission as a modulator of the brain's evolutionary old dynamic defensive system and provide further support for a strong, biologically plausible candidate intermediate phenotype of defensive reactivity. As such, glycine-dependent neurotransmission may open up new avenues for mechanistic research on the etiopathogenesis of fear and anxiety disorders.

Neural correlates of behavioral inhibition in healthy people and in patients with borderline personality disorder and ADHD

Introduction

Deficits in behavioral inhibition leading to impulsivity occur frequently in many otherwise different psychiatric diseases, mainly ADHD and borderline personality disorder (BPD). However, the research is complicated by using of different tests and their parameters. Further, the role of frontoparietal network in behavioral inhibition has been questioned recently.

Objectives

The aims of our studies were:

– to present the influence of differences in inhibition tasks parameters;

– to describe neural correlates of behavioral inhibition in healthy people;

– to compare them with BPD and ADHD patients.

Methods

We implemented two different variants of Go/NoGo Task, one designed for behavioral research and the second for neuroimaging. Thirty healthy participants (37% of women, age range 15 to 33 years) underwent behavioral and fMRI measurement. Further, groups of patients with BPD, ADHD and their healthy controls underwent the Go/NoGo Task under both fMRI and EEG.

Results

The results show differences in behavioral performance based on different task parameters. The fMRI results in healthy people show specific activation patterns within the frontoparietal network associated with inhibition trials (mainly inferior frontal gyrus, insula, cingulate gyrus, SMA, inferior parietal lobule). Further, we present differences between patients with BPD, ADHD and controls in BOLD signal and ERPs.

Conclusions

Go/NoGo Task design substantially influences the subjects’ behavioral performance. Our results with methodologically upgraded Go/NoGo Task design provide support for the inhibition frontoparietal brain network and its different activations in BPD and ADHD patients. The research was supported by Ministry of Health of the Czech Republic, grant nr. 15-30062A.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

T cell receptor repertoires after adoptive transfer of expanded allogeneic regulatory T cells

Regulatory T cell (T_reg ) therapy has been exploited in autoimmune disease, solid organ transplantation and in efforts to prevent or treat graft-versus-host disease (GVHD). However, our knowledge on the in-vivo persistence of transfused T_reg is limited. Whether T_reg transfusion leads to notable changes in the overall T_reg repertoire or whether longevity of T_reg in the periphery is restricted to certain clones is unknown. Here we use T cell receptor alpha chain sequencing (TCR-α-NGS) to monitor changes in the repertoire of T_reg upon polyclonal expansion and after subsequent adoptive transfer. We applied TCR-α-NGS to samples from two patients with chronic GVHD who received comparable doses of stem cell donor derived expanded T_reg . We found that in-vitro polyclonal expansion led to notable repertoire changes in vitro and that T_reg cell therapy altered the peripheral T_reg repertoire considerably towards that of the infused cell product, to different degrees, in each patient. Clonal changes in the peripheral blood were transient and correlated well with the clinical parameters. We suggest that T cell clonotype analyses using TCR sequencing should be considered as a means to monitor longevity and fate of adoptively transferred T cells.

Genetic and neurodevelopmental spectrum of SYNGAP1-associated intellectual disability and epilepsy

OBJECTIVE

We aimed to delineate the neurodevelopmental spectrum associated with SYNGAP1 mutations and to investigate genotype-phenotype correlations.

METHODS

We sequenced the exome or screened the exons of SYNGAP1 in a total of 251 patients with neurodevelopmental disorders. Molecular and clinical data from patients with SYNGAP1 mutations from other centres were also collected, focusing on developmental aspects and the associated epilepsy phenotype. A review of SYNGAP1 mutations published in the literature was also performed.

RESULTS

We describe 17 unrelated affected individuals carrying 13 different novel loss-of-function SYNGAP1 mutations. Developmental delay was the first manifestation of SYNGAP1-related encephalopathy; intellectual disability became progressively obvious and was associated with autistic behaviours in eight patients. Hypotonia and unstable gait were frequent associated neurological features. With the exception of one patient who experienced a single seizure, all patients had epilepsy, characterised by falls or head drops due to atonic or myoclonic seizures, (myoclonic) absences and/or eyelid myoclonia. Triggers of seizures were frequent (n=7). Seizures were pharmacoresistant in half of the patients. The severity of the epilepsy did not correlate with the presence of autistic features or with the severity of cognitive impairment. Mutations were distributed throughout the gene, but spared spliced 3' and 5' exons. Seizures in patients with mutations in exons 4-5 were more pharmacoresponsive than in patients with mutations in exons 8-15.

CONCLUSIONS

SYNGAP1 encephalopathy is characterised by early neurodevelopmental delay typically preceding the onset of a relatively recognisable epilepsy comprising generalised seizures (absences, myoclonic jerks) and frequent triggers.

Diagnostic Impact of Bone-Subtraction CT Angiography for Patients with Acute Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Detection and evaluation of ruptured aneurysms is critical for choosing an appropriate endovascular or neurosurgical intervention. Our aim was to assess whether bone-subtraction CTA is capable of guiding treatment for cerebral aneurysms in patients with acute SAH and could replace DSA.

MATERIALS AND METHODS

We prospectively studied 116 consecutive patients with SAH with 16-detector row bone-subtraction CTA and DSA before intracranial aneurysm treatment. Two independent neuroradiologists reviewed the bone-subtraction CTA blinded to DSA (reference standard). We determined the accuracy of bone-subtraction CTA for aneurysm detection and the measurement of aneurysm dimensions and compared the radiation doses of the 2 imaging modalities.

RESULTS

Seventy-one patients (61%) had 74 aneurysms on DSA. Bone-subtraction CTA detected 73 of these aneurysms, but it detected 1 additional aneurysm. On a per-aneurysm basis, sensitivity, specificity, and positive and negative predictive values for bone-subtraction CTA were 99%, 98%, and 99% and 98%, respectively. For aneurysms of ≤3 mm, sensitivity was 94% (95% CI, 73%-99%). Bone-subtraction CTA slightly overestimated neck and dome diameters by <0.2 mm and overestimated the dome-to-neck ratios by 2% on average. Dose-length product was 565 ± 201 mGy × cm for bone-subtraction CTA and 1609 ± 1300 mGy × cm for DSA.

CONCLUSIONS

Bone-subtraction CTA is as accurate as DSA in detecting cerebral aneurysms after SAH, provides similar information about aneurysm configuration and measures, and reduces the average effective radiation dose for vascular diagnostics by 65%. Diagnostic equivalence in association with dose reduction suggests replacing DSA with bone-subtraction CTA in the diagnostic work-up of spontaneous SAH.

Gastro-Intestinal Tolerance and Renal Safety of Protein Oral Nutritional Supplements in Nursing Home Residents: A Randomized Controlled Trial

BACKGROUND/OBJECTIVE

High protein oral nutritional supplements (ONS) are regularly prescribed to undernourished patients; however usage of these in older adults is being discussed, as their renal function might have declined with age. Therefore, the aim of the current study was to evaluate the effects of 8 week long consumption of high protein ONS on the renal function of nursing home residents in need of supplementation. Furthermore, within the same setup, differences in gastro-intestinal tolerance between a standard and a more concentrated version of an ONS were investigated.

DESIGN

Randomized, controlled, single-blind, parallel-group, multi-country trial (NTR2565).

SETTING

Nursing home.

PARTICIPANTS

67 nursing home residents in need of ONS (energy-dense, small volume group n=32; standard volume group n=35).

INTERVENTION

Protein supplementation was provided by either a standard (200ml, 300kcal, 20g protein) or an energy-dense, small volume (125ml, 300kcal, 18g protein) ONS during the 8 week long study.

MEASUREMENTS

Primary outcome was gastro-intestinal tolerance, assessed by daily stool frequency and consistency, and occurrence and intensity of self-reported gastro-intestinal symptoms. Safety was measured via the occurrence of (serious) adverse events, vital signs, as well as liver- and kidney function monitoring.

RESULTS

No clinically relevant and, except for flatulence, no statistically significant differences in gastro-intestinal tolerance were observed between groups. No significant difference between groups was found for estimated glomerular filtration rate (eGFR) and urinary albumin/creatinine ratio at baseline and week 8, nor for the changes from baseline. Adverse events and the changes in monitored renal parameters over the study period did not point to a deterioration of renal function.

CONCLUSION

High protein ONS seems to be well-tolerated and safe; there is no indication that it affects renal function in nursing home residents, including patients with stage 3 chronic kidney disease, under the conditions tested. Results did not suggest a difference in the effect on renal function between standard and energy-dense small volume ONS format.

Rare KCNJ18 variants do not explain hypokalaemic periodic paralysis in 263 unrelated patients

OBJECTIVE

To examine rare KCNJ18 variations recently reported to cause sporadic and thyrotoxic hypokalaemic periodic paralysis (TPP).

METHODS

We sequenced KCNJ18 in 474 controls (400 Caucasians, 74 male Asians) and 263 unrelated patients with periodic paralysis (PP), including 30 patients with TPP without mutations in established PP genes.

RESULTS

In 10 patients without TPP, we identified 9 heterozygous, novel variations (c.-3G>A, L15S, R81C, E273X, T309I, I340T, N365S, G394R, R401W) and a questionable heterozygous causative R399X stop variant. Studies on 40 relatives of these 10 patients showed that none of the variants were de novo in the patients and that R399X occurred in 3 non-affected relatives. Most affected amino acids lacked conservation and several clinically affected relatives did not carry the patient's variant. T309I, however, could be pathogenic under the pre-requisite of strongly reduced penetrance in females. Of the controls, 17 revealed 12 novel rare variants including the heterozygous E273X stop variant in three individuals.

CONCLUSIONS

Our study shows many different, rare KCNJ18 alterations in patients as well as controls. Only perhaps one meets the requirements of a disease-causing mutation. Therefore, KCNJ18 alterations are seldom pathogenic. Additional studies are required before patients with PP can be genetically diagnosed on the basis of a KCNJ18 variant alone.

Long-Term Observations in an Affected Family with Neurogenic Scapuloperoneal Syndrome Caused by Mutation R269C in the TRPV4 Gene

Mutations in the TRPV4 gene, encoding a polymodal Ca(2+) permeable channel, are causative for several human diseases, affecting the skeletal and the peripheral nervous system with highly variable phenotypes. We report on a family with two affected individuals. The father clinically suffered from a classical scapuloperoneal syndrome, while the son presented with a severe neonatal onset with congenital respiratory distress, feeding problems and arthrogryposis multiplex. Multi-Gene Panel sequencing by next generation sequencing revealed the heterozygous mutation c.805C>T (p.R269C) in the TRPV4 gene. Long-term observation over two decades showed no relevant disease progression in the father and, after a dramatic neonatal period, a significant improvement in the son who became ambulant with orthoses at the age of 5 years, suggesting a reasonably good prognosis even in cases with severe neonatal onset. Long-term findings in muscle ultrasound correlated with the clinical course, showing stable or even slightly improved findings. Neurography revealed a late-onset sensory neuropathy in the father, which was so far not described in TRPV4 neuropathies.

Overlap phenotype between CMT1A and hereditary neuropathy with liability to pressure palsies caused by the novel small in-frame deletion c.407_418del12 in PMP22 gene

We report monozygotic twins, who presented with a clinical picture of Charcot-Marie-Tooth disease type 1 (CMT1) with bilateral foot drop, pes cavus, thoracic kyphosis, and scoliosis. Hereditary neuropathy with liability to pressure palsies (HNPP) showed up in one of them. Neurography showed demyelinating neuropathy, typical for CMT1, and transient conduction block in the ulnar nerve correlating with clinical ulnar palsy due to minor mechanical stress in only one of them. Genetic analysis revealed novel small de novo deletion c.407_418del12 in the PMP22 gene. Our patient shows the rarely reported combination of CMT1A and HNPP, caused by an in-frame deletion in the PMP22 gene. HNPP is in the majority of cases correlated with heterozygous deletion of the whole PMP22 gene or other mutations leading to functional haploinsufficiency. The cases give further evidence that pathogenesis of HNPP is not completely understood and can obviously result from existence of a defective protein, too. The intrafamiliar phenotypic variability, even in monozygotic twins, confirms the well-known fact that factors apart from genetics contribute to the clinical course.

Compliance of energy-dense, small volume oral nutritional supplements in the daily clinical practice on a geriatric ward--an observational study

INTRODUCTION

Compliance is important in optimizing the clinical effectiveness of oral nutritional supplements (ONS). Small volume, energy-dense ONS (ED-ONS; ≥ 2 kcal/ml) have been shown to improve compliance in clinical trial settings. However, data from clinical practice is still lacking. The aim of the present study was to evaluate the effect of ED-ONS on the compliance in an observational set-up to obtain data from daily clinical practice on a geriatric ward.

METHODS

Geriatric inpatients, undernourished or at risk of undernutrition received two servings of either ED-ONS (125 ml, 2.4 kcal/ml: Nutridrink Compact Energy, Nutricia) or a standard ONS (S-ONS; 200 ml, 1.5 kcal/ml: Nutridrink) as part of their daily routine care. Patients were allocated to a group according to availability of beds and placement on the ward. Compliance (kcal/day and % of prescribed volume) was assessed by weighing returned bottles. Data were analyzed via Mixed Model for Repeated Measures.

RESULTS

Forty-seven patients received ED-ONS, and 61 patients received S-ONS. Compliance was significantly higher with ED-ONS in geriatric inpatients compared to S-ONS ( 378 ± 14.0 kcal/day vs. 337 ± 13.6 kcal/day (mean ± SEM), p = 0.039, 63.0 ± 2.34% vs. 56.2 ± 2.26%, p = 0.039). Moreover, a trend (p=0.078) was observed towards an increasing difference in compliance over time.

CONCLUSION

This study shows that compliance to ED-ONS is significantly better than to S-ONS in daily clinical practice. Although small, the difference in compliance seems to increase over time, suggesting clinical relevance with longer treatment.

Serratia marcescens harbouring SME-type class A carbapenemases in Canada and the presence of blaSME on a novel genomic island, SmarGI1-1

OBJECTIVES

An increasing prevalence since 2010 of Serratia marcescens harbouring the Ambler class A carbapenemase SME prompted us to further characterize these isolates.

METHODS

Isolates harbouring bla(SME) were identified by PCR and sequencing. Phenotypic analysis for carbapenemase activity was carried out by a modified Hodge test and a modified Carba NP test. Antimicrobial susceptibilities were determined by Etest and Vitek 2. Typing was by PFGE of macrorestriction digests. Whole-genome sequencing of three isolates was carried out to characterize the genomic region harbouring the bla(SME)-type genes.

RESULTS

All S. marcescens harbouring SME-type enzymes could be detected using a modified Carba NP test. Isolates harbouring bla(SME) were resistant to penicillins and carbapenems, but remained susceptible to third-generation cephalosporins, as well as fluoroquinolones and trimethoprim/sulfamethoxazole. Isolates exhibited diverse genetic backgrounds, though 57% of isolates were found in three clusters. Analysis of whole-genome sequence data from three isolates revealed that the bla(SME) gene occurred in a novel cryptic prophage genomic island, SmarGI1-1.

CONCLUSIONS

There has been an increasing occurrence of S. marcescens harbouring bla(SME) in Canada since 2010. The bla(SME) gene was found on a genomic island, SmarGI1-1, that can be excised and circularized, which probably contributes to its dissemination amongst S. marcescens.