Long-term effectiveness and acceptability of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel disease treated with intensified doses: The REMSWITCH-LT study

BACKGROUND

The long-term risk of relapse after switching from intravenous (IV) to subcutaneous (SC) infliximab remains unknown in inflammatory bowel disease (IBD).

AIMS

To assess the long-term effectiveness and acceptability of switching from IV to SC infliximab in patients with IBD treated with or without an intensified IV regimen.

METHODS

We extended the follow-up of the REMSWITCH study including patients with IBD in clinical remission who were switched from IV to SC infliximab (120 mg/2 weeks). Relapse was defined as clinical relapse or faecal calprotectin increase ≥150 μg/g compared to baseline.

RESULTS

After median follow-up of 18 [15-20] months, among 128 patients, rates of relapse were 13.8% (8/58), 18.4% (7/38), 35.3% (6/17) and 86.7% (13/15) at last follow-up (p < 0.001), in those receiving 5 mg/kg/8 weeks, 10 mg/kg/8 weeks, 10 mg/kg/6 weeks and 10 mg/kg/4 weeks at baseline, respectively. Among relapsing patients, dose escalation led to clinical remission in 82.1% (23/28). In multivariable analyses, factors associated with higher risk of relapse were IV infliximab 10 mg/kg/4 weeks (OR = 61.0 [6.1-607.0], p < 0.001) or 10 mg/kg/6 weeks (OR = 4.7 [1.1-20.2], p = 0.017), and decreased (OR = 5.6 [1.5-20.3], p = 0.004) or stable (OR = 5.0 [1.6-15.0], p = 0.009) serum levels of infliximab between baseline and first post-switch visit. Acceptability was improved at 6 months and did not decrease over time (6.9 ± 1.6 before the switch vs. 8.8 ± 1.3 at 6 months and 8.8 ± 1.3 at last follow-up; p < 0.001). No severe adverse events were reported.

CONCLUSIONS

Switching from IV to SC infliximab 120 mg every other week is safe and well accepted leading to low long-term risk of relapse. Tight monitoring and dose escalation should be recommended for patients receiving 10 mg/kg/6 weeks and 4 weeks, respectively.

Infliximab is an effective option in patients with ulcerative colitis previously exposed to full subcutaneous anti-TNF agent: Results from a real-world multicenter study

BACKGROUND

Data on infliximab efficacy in bio-exposed patients with ulcerative colitis (UC) are limited.

AIMS

To evaluate infliximab effectiveness and its predictors in UC patients with prior exposure to subcutaneous (SC) anti-TNF agent.

METHODS

In this multicenter retrospective study (8 centers), we included all consecutive UC patients with prior exposure to subcutaneous anti-TNF, starting infliximab for symptomatic UC, excluding acute severe colitis. Corticosteroid-free clinical remission (CFREM) was assessed at week 14 (W14) and W52 while endoscopic improvement (CFREM + endoscopic Mayo score≤1) was evaluated at W14.

RESULTS

Overall, 104 patients were included (pancolitis=54.8%, primary failure to subcutaneous anti-TNF=57.4%, concomitant immunosuppressant=53.8%, median partial Mayo score at baseline=7[5-8]). The rate of CFREM was 33.6% (35/104) at W14 and 40.4% (42/104) at W52. At W14, endoscopic improvement was achieved in 29.8%(31/104). In multivariable analysis, concomitant immunosuppressant was associated with higher rate of CFREM at W14(OR=2.83[1.06-7.54], p = 0.037) and W52(OR=2.68[1.16-6.22];p = 0.021), while primary failure to a previous subcutaneous anti-TNF agent led to lower rate of CFREM at W14 (OR=0.37[0.14-0.98], p = 0.046). After a median follow-up of 20.9 months[11.7-33.7]), 50.0%(52/104) patients had discontinued infliximab.

CONCLUSION

Infliximab is an effective option in UC patients previously exposed to prior subcutaneous anti-TNF agent and should be used with concomitant immunosuppressant.

Slc20a1 and Slc20a2 regulate neuronal plasticity and cognition independently of their phosphate transport ability

In recent years, primary familial brain calcification (PFBC), a rare neurological disease characterized by a wide spectrum of cognitive disorders, has been associated to mutations in the sodium (Na)-Phosphate (Pi) co-transporter SLC20A2. However, the functional roles of the Na-Pi co-transporters in the brain remain still largely elusive. Here we show that Slc20a1 (PiT-1) and Slc20a2 (PiT-2) are the most abundant Na-Pi co-transporters expressed in the brain and are involved in the control of hippocampal-dependent learning and memory. We reveal that Slc20a1 and Slc20a2 are differentially distributed in the hippocampus and associated with independent gene clusters, suggesting that they influence cognition by different mechanisms. Accordingly, using a combination of molecular, electrophysiological and behavioral analyses, we show that while PiT-2 favors hippocampal neuronal branching and survival, PiT-1 promotes synaptic plasticity. The latter relies on a likely Otoferlin-dependent regulation of synaptic vesicle trafficking, which impacts the GABAergic system. These results provide the first demonstration that Na-Pi co-transporters play key albeit distinct roles in the hippocampus pertaining to the control of neuronal plasticity and cognition. These findings could provide the foundation for the development of novel effective therapies for PFBC and cognitive disorders.

Real-world EGFR testing practices for non-small-cell lung cancer by thoracic pathology laboratories across Europe

BACKGROUND

Testing for epidermal growth factor receptor (EGFR) mutations is an essential recommendation in guidelines for metastatic non-squamous non-small-cell lung cancer, and is considered mandatory in European countries. However, in practice, challenges are often faced when carrying out routine biomarker testing, including access to testing, inadequate tissue samples and long turnaround times (TATs).

MATERIALS AND METHODS

To evaluate the real-world EGFR testing practices of European pathology laboratories, an online survey was set up and validated by the Pulmonary Pathology Working Group of the European Society of Pathology and distributed to 64 expert testing laboratories. The retrospective survey focussed on laboratory organisation and daily EGFR testing practice of pathologists and molecular biologists between 2018 and 2021.

RESULTS

TATs varied greatly both between and within countries. These discrepancies may be partly due to reflex testing practices, as 20.8% of laboratories carried out EGFR testing only at the request of the clinician. Many laboratories across Europe still favour single-test sequencing as a primary method of EGFR mutation identification; 32.7% indicated that they only used targeted techniques and 45.1% used single-gene testing followed by next-generation sequencing (NGS), depending on the case. Reported testing rates were consistent over time with no significant decrease in the number of EGFR tests carried out in 2020, despite the increased pressure faced by testing facilities during the COVID-19 pandemic. ISO 15189 accreditation was reported by 42.0% of molecular biology laboratories for single-test sequencing, and by 42.3% for NGS. 92.5% of laboratories indicated they regularly participate in an external quality assessment scheme.

CONCLUSIONS

These results highlight the strong heterogeneity of EGFR testing that still occurs within thoracic pathology and molecular biology laboratories across Europe. Even among expert testing facilities there is variability in testing capabilities, TAT, reflex testing practice and laboratory accreditation, stressing the need to harmonise reimbursement technologies and decision-making algorithms in Europe.

Long term worsening of amyloid pathology, cerebral function, and cognition after a single inoculation of beta-amyloid seeds with Osaka mutation

Alzheimer's disease (AD) is characterized by intracerebral deposition of abnormal proteinaceous assemblies made of amyloid-β (Aß) peptides or tau proteins. These peptides and proteins induce synaptic dysfunctions that are strongly correlated with cognitive decline. Intracerebral infusion of well-defined Aβ seeds from non-mutated Aβ_1-40 or Aβ_1-42 peptides can increase Aβ depositions several months after the infusion. Familial forms of AD are associated with mutations in the amyloid precursor protein (APP) that induce the production of Aβ peptides with different structures. The Aβ Osaka (Aβ_osa mutation (E693Δ)) is located within the Aβ sequence and thus the Aβ_osa peptides have different structures and properties as compared to non-mutated Aβ_1-42 peptides (Aβ_wt). Here, we wondered if a single exposure to this mutated Aβ can worsen AD pathology as well as downstream events including cognition, cerebral connectivity and synaptic health several months after the inoculation. To answer this question we inoculated Aβ_1-42-bearing Osaka mutation (Aβ_osa) in the dentate gyrus of APP_swe/PS1_dE9 mice at the age of two months. Their cognition and cerebral connectivity were analyzed at 4 months post-inoculation by behavioral evaluation and functional MRI. Aβ pathology as well as synaptic density were evaluated by histology. The impact of Aβ_osa peptides on synaptic health was also measured on primary cortical neurons. Remarkably, the intracerebral administration of Aβ_osa induced cognitive and synaptic impairments as well as a reduction of functional connectivity between different brain regions, 4 months post-inoculation. It increased Aβ plaque depositions and increased Aβ oligomers. This is the first study showing that a single, sporadic event as Aβ_osa inoculation can worsen the fate of the pathology and clinical outcome several months after the event. It suggests that a single inoculation of Aβ regulates a large cascade of events for a long time.

Treating early postnatal circuit defect delays Huntington's disease onset and pathology in mice

Recent evidence has shown that even mild mutations in the Huntingtin gene that are associated with late-onset Huntington's disease (HD) disrupt various aspects of human neurodevelopment. To determine whether these seemingly subtle early defects affect adult neural function, we investigated neural circuit physiology in newborn HD mice. During the first postnatal week, HD mice have less cortical layer 2/3 excitatory synaptic activity than wild-type mice, express fewer glutamatergic receptors, and show sensorimotor deficits. The circuit self-normalizes in the second postnatal week but the mice nonetheless develop HD. Pharmacologically enhancing glutamatergic transmission during the neonatal period, however, rescues these deficits and preserves sensorimotor function, cognition, and spine and synapse density as well as brain region volume in HD adult mice.

Diversity of plant parasitic nematodes characterized from fields of the French national monitoring programme for the Columbia root-knot nematode

Plant parasitic nematodes are highly abundant in all agrosystems and some species can have a major impact on crop yields. To avoid the use of chemical agents and to find alternative methods to manage these pests, research studies have mainly focused on plant resistance genes and biocontrol methods involving host plants or natural enemies. A specific alternative method may consist in supporting non-damaging indigenous species that could compete with damaging introduced species to decrease and keep their abundance at low level. For this purpose, knowledge about the biodiversity, structure and functioning of these indigenous communities is needed in order to carry out better risk assessments and to develop possible future management strategies. Here, we investigated 35 root crop fields in eight regions over two consecutive years. The aims were to describe plant parasitic nematode diversity and to assess the potential effects of cultivation practices and environmental variables on communities. Community biodiversity included 10 taxa of plant parasitic nematodes. Despite no significant abundance variations between the two sampling years, structures of communities varied among the different regions. Metadata collected for the past six years, characterizing the cultural practices and soils properties, made it possible to evaluate the impact of these variables both on the whole community and on each taxon separately. Our results suggest that, at a large scale, many variables drive the structuration of the communities. Soil variables, but also rainfall, explain the population density variations among the geographical areas. The effect of the variables differed among the taxa, but fields with few herbicide applications and being pH neutral with low heavy metal and nitrogen concentrations had the highest plant parasitic nematode densities. We discuss how these variables can affect nematode communities either directly or indirectly. These types of studies can help to better understand the variables driving the nematode communities structuration in order to support the abundance of indigenous non-damaging communities that could compete with the invasive species.

OUP accepted manuscript

Microtubules play fundamental roles in the maintenance of neuronal processes and in synaptic function and plasticity. While dynamic microtubules are mainly composed of tyrosinated tubulin, long-lived microtubules contain detyrosinated tubulin, suggesting that the tubulin tyrosination/detyrosination cycle is a key player in the maintenance of microtubule dynamics and neuronal homeostasis, conditions that go awry in neurodegenerative diseases. In the tyrosination/detyrosination cycle, the C-terminal tyrosine of α-tubulin is removed by tubulin carboxypeptidases and re-added by tubulin tyrosine ligase (TTL).

Here we show that TTL heterozygous mice exhibit decreased tyrosinated microtubules, reduced dendritic spine density and both synaptic plasticity and memory deficits. We further report decreased TTL expression in sporadic and familial Alzheimer’s disease, and reduced microtubule dynamics in human neurons harbouring the familial APP-V717I mutation. Finally, we show that synapses visited by dynamic microtubules are more resistant to oligomeric amyloid-β peptide toxicity and that expression of TTL, by restoring microtubule entry into spines, suppresses the loss of synapses induced by amyloid-β peptide.

Together, our results demonstrate that a balanced tyrosination/detyrosination tubulin cycle is necessary for the maintenance of synaptic plasticity, is protective against amyloid-β peptide-induced synaptic damage and that this balance is lost in Alzheimer’s disease, providing evidence that defective tubulin retyrosination may contribute to circuit dysfunction during neurodegeneration in Alzheimer’s disease.

[Giant condyloma acuminatum in pregnancy]

Buschke Lownestein's tumour is a giant acuminate condyloma characterised by its degenerative potential, its invasive nature and its recurrence after treatment. It is a rare condition, transmitted mainly by sexual transmission and induced by to the human papillomavirus (HPV). The discussion will be illustrated by a clinical case The treatment is still under discussion but surgery seems to be the best option. Management during pregnancy is more complex since it must take into account the mother and her fetus. The delivery route is still debated. The post-treatment evolution was satisfactory and without recurrence until the delivery which, due to the antecedent of 3 caesarean sections, was carried out by cesarean section. HPV vaccination, sex education and early treatment of condyloma lesions should prevent and in any case improve the prognosis of this disease.

Astrocyte-neuron interplay is critical for Alzheimer's disease pathogenesis and is rescued by TRPA1 channel blockade

The sequence of cellular dysfunctions in preclinical Alzheimer's disease must be understood if we are to plot new therapeutic routes. Hippocampal neuronal hyperactivity is one of the earliest events occurring during the preclinical stages of Alzheimer's disease in both humans and mouse models. The most common hypothesis describes amyloid β accumulation as the triggering factor of the disease but the effects of this accumulation and the cascade of events leading to cognitive decline remain unclear. In mice, we previously showed that amyloid β-dependent TRPA1 channel activation triggers hippocampal astrocyte hyperactivity, subsequently inducing hyperactivity in nearby neurons. In this work, we investigated the potential protection against Alzheimer's disease progression provided by early chronic pharmacological inhibition of TRPA1 channel. A specific inhibitor of TRPA1 channel (HC030031) was administered intraperitoneally from the onset of amyloid β overproduction in the APP/PS1-21 mouse model of Alzheimer's disease. Short-, medium-, and long-term effects of this chronic pharmacological TRPA1 blockade were characterized on Alzheimer's disease progression at functional (astrocytic and neuronal activity), structural, biochemical, and behavioural levels. Our results revealed that the first observable disruptions in the Alzheimer's disease transgenic mouse model used correspond to aberrant hippocampal astrocyte and neuron hyperactivity. We showed that chronic TRPA1 blockade normalizes astrocytic activity, avoids perisynaptic astrocytic process withdrawal, prevents neuronal dysfunction and preserves structural synaptic integrity. These protective effects preserved spatial working-memory in this Alzheimer's disease mouse model. The toxic effect of amyloid β on astrocytes triggered by TRPA1 channel activation is pivotal to Alzheimer's disease progression. TRPA1 blockade prevents irreversible neuronal dysfunction, making this channel a potential therapeutic target to promote neuroprotection.

Defining and Assessing the Reproducibility of Crohn's Disease Endoscopic Lesions: A Delphi-like Method from the GETAID

BACKGROUND AND AIMS

Defining and assessing the reproducibility of Crohn's disease [CD] endoscopic lesions is essential in assessing endoscopic healing.

METHODS

Twelve endoscopic CD experts from the GETAID defined aphthoid erosions [AE], superficial ulcerations [SU], deep ulcerations [DU], stenosis, and fistulas according to a Delphi-like method. Thirty different GETAID physicians declared if they found acceptable each definition. Intra- and inter-observer agreements were investigated using 100 videos with one tagged specific lesion [AE, SU, DU, or sham lesion] read by 15 independent endoscopists at baseline and 1 month later in a randomised order. Video quality was determined by an external reader. According to kappa estimate [κ ±standard error], intra or inter-observer agreement was qualified as 'moderate' [0.4-0.6], 'substantial' [0.6-0.8], or 'almost perfect' [0.8-1.0].

RESULTS

Among 30 different experts, 83% to 97% found acceptable the definitions retrieved from the Delphi-like method. Intra-observer κ was 0.717 [±0.019] for SU, 0.681 [±0.027] for AE, 0.856 [±0.014] for DU, showing 'substantial' agreement. It was 0.801 [±0.016] for any ulceration [DU or SU]. There was a high variability across readers from 'moderate' to 'almost perfect' agreement. Inter-observer κ was 0.548 [±0.042] for SU, 0.554 [±0.028] for AE 0.694 [±0.041] for DU, and 0.705 [±0.042] for any ulceration. Inter-observer agreement increased when reading the 53 high-quality videos: 0.787 [±0.064] [p = 0.001], 0.607 [±0.043] [p = 0.001], and 0.782 [±0.064][p = 0.001] for DU, AE, and any ulceration, respectively.

CONCLUSIONS

Despite variable intra-agreement level across readers, the GETAID definitions for CD endoscopic lesions provided 'substantial' inter-observer agreements, especially in case of high-quality videos.

VEGF counteracts amyloid-β-induced synaptic dysfunction

The vascular endothelial growth factor (VEGF) pathway regulates key processes in synapse function, which are disrupted in early stages of Alzheimer's disease (AD) by toxic-soluble amyloid-beta oligomers (Aβo). Here, we show that VEGF accumulates in and around Aβ plaques in postmortem brains of patients with AD and in APP/PS1 mice, an AD mouse model. We uncover specific binding domains involved in direct interaction between Aβo and VEGF and reveal that this interaction jeopardizes VEGFR2 activation in neurons. Notably, we demonstrate that VEGF gain of function rescues basal synaptic transmission, long-term potentiation (LTP), and dendritic spine alterations, and blocks long-term depression (LTD) facilitation triggered by Aβo. We further decipher underlying mechanisms and find that VEGF inhibits the caspase-3-calcineurin pathway responsible for postsynaptic glutamate receptor loss due to Aβo. These findings provide evidence for alterations of the VEGF pathway in AD models and suggest that restoring VEGF action on neurons may rescue synaptic dysfunction in AD.

Pyr1-Mediated Pharmacological Inhibition of LIM Kinase Restores Synaptic Plasticity and Normal Behavior in a Mouse Model of Schizophrenia

The search for effective treatments for neuropsychiatric disorders is ongoing, with progress being made as brain structure and neuronal function become clearer. The central roles played by microtubules (MT) and actin in synaptic transmission and plasticity suggest that the cytoskeleton and its modulators could be relevant targets for the development of new molecules to treat psychiatric diseases. In this context, LIM Kinase - which regulates both the actin and MT cytoskeleton especially in dendritic spines, the post-synaptic compartment of the synapse - might be a good target. In this study, we analyzed the consequences of blocking LIMK1 pharmacologically using Pyr1. We investigated synaptic plasticity defects and behavioral disorders in MAP6 KO mice, an animal model useful for the study of psychiatric disorders, particularly schizophrenia. Our results show that Pyr1 can modulate MT dynamics in neurons. In MAP6 KO mice, chronic LIMK inhibition by long-term treatment with Pyr1 can restore normal dendritic spine density and also improves long-term potentiation, both of which are altered in these mice. Pyr1 treatment improved synaptic plasticity, and also reduced social withdrawal and depressive/anxiety-like behavior in MAP6 KO mice. Overall, the results of this study validate the hypothesis that modulation of LIMK activity could represent a new therapeutic strategy for neuropsychiatric diseases.

Assembly of The Mitochondrial Complex I Assembly Complex Suggests a Regulatory Role for Deflavination

Fatty acid β‐oxidation (FAO) and oxidative phosphorylation (OXPHOS) are mitochondrial redox processes that generate ATP. The biogenesis of the respiratory Complex I, a 1 MDa multiprotein complex that is responsible for initiating OXPHOS, is mediated by assembly factors including the mitochondrial complex I assembly (MCIA) complex. However, the organisation and the role of the MCIA complex are still unclear. Here we show that ECSIT functions as the bridging node of the MCIA core complex. Furthermore, cryo‐electron microscopy together with biochemical and biophysical experiments reveal that the C‐terminal domain of ECSIT directly binds to the vestigial dehydrogenase domain of the FAO enzyme ACAD9 and induces its deflavination, switching ACAD9 from its role in FAO to an MCIA factor. These findings provide the structural basis for the MCIA complex architecture and suggest a unique molecular mechanism for coordinating the regulation of the FAO and OXPHOS pathways to ensure an efficient energy production.

Early Transmural Response Assessed Using Magnetic Resonance Imaging Could Predict Sustained Clinical Remission and Prevent Bowel Damage in Patients with Crohn's Disease Treated with Anti-Tumour Necrosis Factor Therapy

BACKGROUND

Magnetic resonance imaging [MRI] is a promising tool to evaluate therapeutic efficacy in ileocolonic Crohn's disease [CD].

AIMS

We aimed to assess the feasibility of early MRI evaluation (week 12 [W12]) to predict corticosteroid-free remission [CFREM] at W52 and prevent long-term bowel damage.

METHODS

All patients with active CD needing anti-tumour necrosis factor [anti-TNF] therapy were consecutively enrolled in this multicentre prospective study. MRI was performed before starting therapy, at W12 and W52. CFREM was defined as Crohn's Disease Activity Index < 150, C-reactive protein < 5 mg/L and faecal calprotectin < 250 µg/g, with no switch of anti-TNF agents, no bowel resection and no therapeutic intensification between W12 and W52.

RESULTS

Among 46 patients, 22 [47.8%] achieved CFREM at W52. Anti-TNF agents were able to heal almost all CD lesions as soon as W12 [p < 0.05]. Early transmural response defined as a 25% decrease of either Clermont score (odds ratio [OR] = 7.7 [1.7-34.0], p < 0.001) or Magnetic Resonance Index of Activity (OR = 4.2 [1.3-13.3], p = 0.015) was predictive of CFREM at W52. Achieving at least two items on W12-MRI among ulceration healing, disappearance of enlarged lymph nodes or sclerolipomatosis, ΔADC [apparent diffusion coefficient] > +10% or ΔRCE [relative contrast enhancement] > -30% was associated with a likelihood of CFREM at W52 of 84.6% vs 37.5% in patients without transmural response [p < 0.001]. Early transmural response could prevent bowel damage progression over time using Clermont score (hazard ratio = 0.21 [0.0-0.9]; p = 0.037).

CONCLUSION

Evaluation of early transmural response by MRI is feasible and is a promising end point to monitor therapeutic efficacy in patients with CD.

Improved optical slicing by stimulated emission depletion light sheet microscopy

Three-dimensional microscopy is mandatory for biological investigation. We describe a stimulated emission depletion selective plane illumination microscope (STED-SPIM) that provides both ease of implementation and an efficient optical slicing. This self-aligned system is based on a single diode-pumped solid-state laser and phase masks made of simple cover glass. A three-fold reduction of the light sheet thickness is achieved together with an enhancement of the sheet uniformity. This method is validated by using fluorescent microspheres and thick slices of fixed and clarified mouse brain to provide an enhanced imaging of Alzheimer's disease models.

Reduction in the neuronal surface of post and presynaptic GABAB receptors in the hippocampus in a mouse model of Alzheimer's disease

The hippocampus plays key roles in learning and memory and is a main target of Alzheimer's disease (AD), which causes progressive memory impairments. Despite numerous investigations about the processes required for the normal hippocampal functions, the neurotransmitter receptors involved in the synaptic deficits by which AD disables the hippocampus are not yet characterized. By combining histoblots, western blots, immunohistochemistry and high-resolution immunoelectron microscopic methods for GABA_B receptors, this study provides a quantitative description of the expression and the subcellular localization of GABA_B1 in the hippocampus in a mouse model of AD at 1, 6 and 12 months of age. Western blots and histoblots showed that the total amount of protein and the laminar expression pattern of GABA_B1 were similar in APP/PS1 mice and in age-matched wild-type mice. In contrast, immunoelectron microscopic techniques showed that the subcellular localization of GABA_B1 subunit did not change significantly in APP/PS1 mice at 1 month of age, was significantly reduced in the stratum lacunosum-moleculare of CA1 pyramidal cells at 6 months of age and significantly reduced at the membrane surface of CA1 pyramidal cells at 12 months of age. This reduction of plasma membrane GABA_B1 was paralleled by a significant increase of the subunit at the intracellular sites. We further observed a decrease of membrane-targeted GABA_B receptors in axon terminals contacting CA1 pyramidal cells. Our data demonstrate compartment- and age-dependent reduction of plasma membrane-targeted GABA_B receptors in the CA1 region of the hippocampus, suggesting that this decrease might be enough to alter the GABA_B -mediated synaptic transmission taking place in AD.

Impact of a checklist used by pharmacists on hospital antimicrobial use: a patient-level interrupted time series study

BACKGROUND

Antimicrobial misuse leading to drug resistance is a growing concern for clinicians. Improving antimicrobial stewardship programmes through development of new tools could be part of the solution.

AIM

To evaluate antimicrobial use in hospitalized patients after implementation of an antimicrobial checklist for ward-based clinical pharmacists.

METHODS

A checklist based on quality indicators of optimal antimicrobial use was implemented to standardize hospital pharmacists' assessments of antimicrobial therapy. Antimicrobial use metrics from adults hospitalized during the control and intervention periods were assessed in an interrupted time series analysis of individual patient data. The primary endpoint was days of therapy (DOT) for all antimicrobials per 1000 days present for included patients. Secondary endpoints were the DOT of extended-spectrum antimicrobials (DOT-ES), length of therapy of all antimicrobials (LOT) and the number of pharmacist interventions.

FINDINGS

One-thousand six-hundred and nineteen patients were included: 800 and 819 in the pre- and post-checklist implementation periods, respectively. As indicated by the point estimates and their 95% confidence intervals (CIs), there were no changes in trend for DOT, DOT-ES or LOT. A change in level was not found for the DOT, while a change of -118 DOT-ES [-209,-28] and -51 LOT [-97,-4] was documented. Furthermore, pharmacists' interventions regarding antimicrobials increased by 18.7% (14.0, 23.5) and progress notes by 32.3% (27.8, 36.8).

CONCLUSION

An antimicrobial checklist used by ward-based clinical pharmacists did not decrease DOT for all antimicrobials, but decreased DOT-ES and LOT upon its implementation.

Adalimumab for patients with Crohn's disease complicated by intra-abdominal abscess: a multicentre, prospective, observational cohort study

doi:10.1093/ecco-jcc/jjy222 Abstract P528 from the 'Poster presentations' section of the main abstract book has been withdrawn and re-inserted as DOP63 in the 'Late-breaking abstracts' section.

Autophagy Is Required for Memory Formation and Reverses Age-Related Memory Decline

Age-related declines in cognitive fitness are associated with a reduction in autophagy, an intracellular lysosomal catabolic process that regulates protein homeostasis and organelle turnover. However, the functional significance of autophagy in regulating cognitive function and its decline during aging remains largely elusive. Here, we show that stimulating memory upregulates autophagy in the hippocampus. Using hippocampal injections of genetic and pharmacological modulators of autophagy, we find that inducing autophagy in hippocampal neurons is required to form novel memory by promoting activity-dependent structural and functional synaptic plasticity, including dendritic spine formation, neuronal facilitation, and long-term potentiation. We show that hippocampal autophagy activity is reduced during aging and that restoring its levels is sufficient to reverse age-related memory deficits. Moreover, we demonstrate that systemic administration of young plasma into aged mice rejuvenates memory in an autophagy-dependent manner, suggesting a prominent role for autophagy to favor the communication between systemic factors and neurons in fostering cognition. Among these youthful factors, we identify osteocalcin, a bone-derived molecule, as a direct hormonal inducer of hippocampal autophagy. Our results reveal that inducing autophagy in hippocampal neurons is a necessary mechanism to enhance the integration of novel stimulations of memory and to promote the influence of systemic factors on cognitive fitness. We also demonstrate the potential therapeutic benefits of modulating autophagy in the aged brain to counteract age-related cognitive impairments.

Long-term efficacy and safety of ustekinumab in 122 refractory Crohn's disease patients: a multicentre experience

BACKGROUND

Long-term outcome of ustekinumab in Crohn's disease (CD) has not been evaluated.

AIM

To evaluate the long-term efficacy and safety of ustekinumab and identify the predictive factors of ustekinumab failure-free persistence in a cohort of anti-TNF refractory CD patients.

METHODS

We performed a retrospective multicentre cohort study including all consecutive CD patients who began subcutaneous ustekinumab and presented a clinical response (defined as a significant improvement of CD-related clinical symptoms assessed by the patient's physician leading to continued ustekinumab) during the first year of treatment. Primary outcome was treatment failure defined as withdrawal of treatment due to loss of response, intolerance or need for surgery.

RESULTS

Eighty-eight of the 122 (72%) CD patients beginning ustekinumab from March 2011 to December 2014, responded to ustekinumab and were followed up until November 2016. Median time on ustekinumab was 26.6 (13.4-34.4) months. Forty-seven patients (54%) continued ustekinumab with a clinical response and 38 (43%) stopped treatment (32 for failure, five for remission and one for pregnancy). Endoscopic response was observed in 82% of patients with endoscopic evaluation and mucosal healing in 39%. Ustekinumab failure-free persistence rates were 78% at 12 months, 66% at 24 months and 55% at 36 months. No predictive factor of ustekinumab failure-free persistence was identified. One severe adverse event was observed (anal adenocarcinoma).

CONCLUSION

In this cohort of refractory CD patients receiving long-term ustekinumab therapy, more than 50% of patients continued ustekinumab treatment with no loss of response, intolerance or surgery and with a good safety profile.

Impact of vedolizumab therapy on extra-intestinal manifestations in patients with inflammatory bowel disease: a multicentre cohort study nested in the OBSERV-IBD cohort

BACKGROUND

The effectiveness of vedolizumab as a treatment for extraintestinal manifestations (EIM) is questionable due to its gut-specificity.

AIM

To assess effectiveness of vedolizumab for EIM in patients with inflammatory bowel disease (IBD) in a large real-life experience cohort.

METHODS

Between June and December 2014, 173 patients with Crohn's disease and 121 with ulcerative colitis were treated with vedolizumab. Patients were followed until week 54. EIM activity was assessed at weeks 0, 6, 14, 22, 30 and 54 by using a 3-step scale: complete remission, partial response and no response.

RESULTS

At baseline, 49 (16.7%) patients had EIMs of which 47 had inflammatory arthralgia/arthritis, four had cutaneous lesions and two had both rheumatologic and skin EIM. At week 54, 21 (44.7%) patients had complete remission for inflammatory arthralgia/arthritis and three (75%) for cutaneous EIM. In multivariate analysis, complete remission of inflammatory arthralgia/arthritis was associated with clinical remission of IBD (OR = 1.89, IC95% [1.05-3.41], P = .03) and recent onset of inflammatory arthralgia/arthritis (OR = 1.99, IC95% [1.12-3.52], P = .02). During the follow-up period, 34 (13.8%) patients without any EIM at baseline, developed incident cases of inflammatory arthralgia/arthritis consisting mostly of peripheral arthralgia without evidence of arthritis and 14 (4.8%) incident cases of paradoxical skin manifestation.

CONCLUSION

Vedolizumab therapy is commonly associated with improvement in EIM. This was associated with quiescent IBD and recent EIM. However, paradoxical skin manifestation and inflammatory arthralgia/arthritis may occur upon vedolizumab therapy.

Efficacy and safety of golimumab in Crohn's disease: a French national retrospective study

BACKGROUND

Anti-tumour necrosis factor (TNF) agents have improved the care of Crohn's disease (CD). After the first anti-TNF discontinuation, it is possible to switch to another anti-TNF. Three anti-TNF agents are available for ulcerative colitis (infliximab, adalimumab and golimumab), but only the first 2 have been approved for CD because golimumab has not been studied for this indication.

AIM

To report the efficacy and safety of golimumab in CD.

METHODS

Crohn's disease patients who received golimumab were identified in 12 French tertiary centres and were retrospectively analysed. The primary endpoint was the duration of golimumab treatment before escalation or discontinuation. The clinical response was defined as a decrease of more than 3 points in the Harvey-Bradshaw index or by global physician assessment.

RESULTS

One hundred and fifteen patients were included. The golimumab treatment duration was 9.8 months (0.55-44), and 48.7% of the patients were still under treatment at the end of follow-up. Clinical response was observed in 55.8% of the patients after a mean duration of 3.8 months. The probability of remaining under treatment without escalation at 6, 12 and 24 months was 54.6%, 34.9% and 19.3% respectively. In multivariate analysis, discontinuation of the first anti-TNF agent due to intolerance (odds ratio, OR = 2.16; 95% CI, confidence interval [1.25-3.86]; P = .005) and co-immunosuppression for more than 6 months (OR = 3.98; 95% CI [2.3-7.1]; P < .0001) were predictive factors of efficacy. Six per cent of the patients discontinued treatment due to intolerance.

CONCLUSION

After failure of infliximab or adalimumab for Crohn's disease, golimumab was safe and seemed beneficial in half of the patients.

Inflammatory gastrointestinal diseases associated with PD-1 blockade antibodies

BACKGROUND

Immune check-point blockade agents have shown clinical activity in cancer patients but are associated with immune-related adverse events that could limit their development. The aim of this study was to describe the gastrointestinal immune-related adverse events (GI-irAE) in patients with cancer treated with anti-PD-1.

METHODS

this is a retrospective study of consecutive adult patients who had a suspected GI-irAE due to anti-PD-1 antibodies between 2013 and 2016. Patients were recruited through a pharmacovigilance registry. Patients' data were reviewed by a multidisciplinary committee that included gastroenterologists, oncologists and a pathologist. Quantitative variables are described by median (range), qualitative variable by frequency (percentage).

RESULTS

Forty-four patients were addressed to a Gastroenterology unit for a suspected GI-IrAE. Twenty patients had a confirmed GI-irAE related to anti-PD-1, which occurred 4.2 months (0.2; 22.1) after the initiation of anti-PD-1. GI-IrAE incidence rate under anti-PD-1 treatment was estimated to be 1.5%. Among patients with GI-IrAE, main symptoms were diarrhoea (n = 16, 80%), abdominal pain (n = 13, 65%), nausea and vomiting (n = 11, 55%), intestinal obstruction (n = 1, 5%), and haematochezia (n = 2, 10%). No patient had colectomy. Four distinct categories of GI-irAE were observed: acute colitis (n = 8, 40%), microscopic colitis (n = 7, 35%), upper gastrointestinal tract inflammation (n = 4, 20%) and pseudo-obstruction (n = 1, 5%). Response rates to corticosteroids were 87.5% (7/8) in acute colitis, 57% (4/7) in microscopic colitis and 75% (3/4) in upper gastrointestinal tract inflammation. Median time to resolution was 36 days (6-172) in acute colitis, and 98 days (42-226) in microscopic colitis.

CONCLUSION

This study suggests that GI-irAE are different and less frequent with anti PD-1 than with anti CTLA-4.

One-year effectiveness and safety of vedolizumab therapy for inflammatory bowel disease: a prospective multicentre cohort study

BACKGROUND

We recently showed that vedolizumab is effective in patients with Crohn's disease (CD) and ulcerative colitis (UC) with prior anti-TNF failure in a multicentre compassionate early-access programme before marketing authorisation was granted to vedolizumab.

AIMS

To assess effectiveness and safety of vedolizumab at week 54 in patients UC and CD.

METHODS

Between June and December 2014, 173 patients with Crohn's disease (CD) and 121 with ulcerative colitis (UC) were treated with vedolizumab induction therapy. Among those 294 patients, 272 completed the induction period and were evaluated at the week 14 visit (161 patients with CD and 111 with UC). Disease activity was assessed using the Harvey-Bradshaw Index for CD and the partial Mayo Clinic score for UC. The primary outcome was steroid-free clinical remission at week 54.

RESULTS

At week 54, steroid-free clinical remission rates at week 54 were 27.2% and 40.5% in patients with CD and UC respectively. In addition, the sustained steroid-free clinical remission (from week 14 to week 54) rates were 8.1% and 19.0% respectively. No deaths were observed. Severe adverse events occurred in 17 (7.2%) patients, including six (2.5%) leading to vedolizumab discontinuation.

CONCLUSION

Vedolizumab is able to maintain steroid-free clinical remission in up to one-third of patients with UC and CD at week 54 with a reasonable safety profile. A significant number of patients experienced loss of response during the first year of treatment, particularly in patients with CD.

Involvement of CRF2 signaling in enterocyte differentiation

AIM

To determine the role of corticotropin releasing factor receptor (CRF2) in epithelial permeability and enterocyte cell differentiation.

METHODS

For this purpose, we used rat Sprague Dawley and various colon carcinoma cell lines (SW620, HCT8R, HT-29 and Caco-2 cell lines). Expression of CRF2 protein was analyzed by fluorescent immunolabeling in normal rat colon and then by western blot in dissociated colonic epithelial cells and in the lysates of colon carcinoma cell lines or during the early differentiation of HT-29 cells (ten first days). To assess the impact of CRF2 signaling on colonic cell differentiation, HT-29 and Caco-2 cells were exposed to Urocortin 3 recombinant proteins (Ucn3, 100 nmol/L). In some experiments, cells were pre-exposed to the astressin 2b (A2b) a CRF2 antagonist in order to inhibit the action of Ucn3. Intestinal cell differentiation was first analyzed by functional assays: the trans-cellular permeability and the para-cellular permeability were determined by Dextran-FITC intake and measure of the transepithelial electrical resistance respectively. Morphological modifications associated to epithelial dysfunction were analyzed by confocal microscopy after fluorescent labeling of actin (phaloidin-TRITC) and intercellular adhesion proteins such as E-cadherin, p120ctn, occludin and ZO-1. The establishment of mature adherens junctions (AJ) was monitored by following the distribution of AJ proteins in lipid raft fractions, after separation of cell lysates on sucrose gradients. Finally, the mRNA and the protein expression levels of characteristic markers of intestinal epithelial cell (IEC) differentiation such as the transcriptional factor krüppel-like factor 4 (KLF4) or the dipeptidyl peptidase IV (DPPIV) were performed by RT-PCR and western blot respectively. The specific activities of DPPIV and alkaline phosphatase (AP) enzymes were determined by a colorimetric method.

RESULTS

CRF2 protein is preferentially expressed in undifferentiated epithelial cells from the crypts of colon and in human colon carcinoma cell lines. Furthermore, CRF2 expression is down regulated according to the kinetic of HT-29 cell differentiation. By performing functional assays, we found that Ucn3-induced CRF2 signaling alters both para- and trans-cellular permeability of differentiated HT-29 and Caco-2 cells. These effects are partly mediated by Ucn3-induced morphological changes associated with the disruption of mature AJ in HT-29 cells and tight junctions (TJ) in Caco-2 cells. Ucn3-mediated activation of CRF2 decreases mRNA and protein expression levels of KLF4 a transcription factor involved in IEC differentiation. This signaling is correlated to a down-regulation of key IEC markers such as DPPIV and AP, at both transcriptional and post-transcriptional levels.

CONCLUSION

Our findings suggest that CRF2 signaling could modulate IEC differentiation. These mechanisms could be relevant to the stress induced epithelial alterations found in inflammatory bowel diseases.

TRPA1 channels promote astrocytic Ca2+ hyperactivity and synaptic dysfunction mediated by oligomeric forms of amyloid-β peptide

BACKGROUND

Excessive synaptic loss is thought to be one of the earliest events in Alzheimer's disease (AD). However, the key mechanisms that maintain plasticity of synapses during adulthood or initiate synapse dysfunction in AD remain unknown. Recent studies suggest that astrocytes contribute to functional changes observed during synaptic plasticity and play a major role in synaptic dysfunction but astrocytes behavior and involvement in early phases of AD remained largely undefined.

METHODS

We measure astrocytic calcium activity in mouse CA1 hippocampus stratum radiatum in both the global astrocytic population and at a single cell level, focusing in the highly compartmentalized astrocytic arbor. Concurrently, we measure excitatory post-synaptic currents in nearby pyramidal neurons.

RESULTS

We find that application of soluble Aβ oligomers (Aβo) induced fast and widespread calcium hyperactivity in the astrocytic population and in the microdomains of the astrocyte arbor. We show that astrocyte hyperactivity is independent of neuronal activity and is repaired by transient receptor potential A1 (TRPA1) channels blockade. In return, this TRPA1 channels-dependent hyperactivity influences neighboring CA1 neurons triggering an increase in glutamatergic spontaneous activity. Interestingly, in an AD mouse model (APP/PS1-21 mouse), astrocyte calcium hyperactivity equally takes place at the beginning of Aβ production, depends on TRPA1 channels and is linked to CA1 neurons hyperactivity.

CONCLUSIONS

Our experiments demonstrate that astrocytes contribute to early Aβo toxicity exhibiting a global and local Ca2+ hyperactivity that involves TRPA1 channels and is related to neuronal hyperactivity. Together, our data suggest that astrocyte is a frontline target of Aβo and highlight a novel mechanism for the understanding of early synaptic dysregulation induced by soluble Aβo species.

The amyloid-β oligomer Aβ*56 induces specific alterations in neuronal signaling that lead to tau phosphorylation and aggregation

Oligomeric forms of amyloid-forming proteins are believed to be the principal initiating bioactive species in many neurodegenerative disorders, including Alzheimer's disease (AD). Amyloid-β (Aβ) oligomers are implicated in AD-associated phosphorylation and aggregation of the microtubule-associated protein tau. To investigate the specific molecular pathways activated by different assemblies, we isolated various forms of Aβ from Tg2576 mice, which are a model for AD. We found that Aβ*56, a 56-kDa oligomer that is detected before patients develop overt signs of AD, induced specific changes in neuronal signaling. In primary cortical neurons, Aβ*56 interacted with N-methyl-d-aspartate receptors (NMDARs), increased NMDAR-dependent Ca²⁺ influx, and consequently increased intracellular calcium concentrations and the activation of Ca²⁺-dependent calmodulin kinase IIα (CaMKIIα). In cultured neurons and in the brains of Tg2576 mice, activated CaMKIIα was associated with increased site-specific phosphorylation and missorting of tau, both of which are associated with AD pathology. In contrast, exposure of cultured primary cortical neurons to other oligomeric Aβ forms (dimers and trimers) did not trigger these effects. Our results indicate that distinct Aβ assemblies activate neuronal signaling pathways in a selective manner and that dissecting the molecular events caused by each oligomer may inform more effective therapeutic strategies.

GluN2B Subunit Labeling with Fluorescent Probes and High-Resolution Live Imaging

Laser Scanning Confocal Microscopy (LSCM) imaging using an appropriate fluorescent probe enables the visualization of a molecular target with high resolution, and represents a method of choice for studying expression, subcellular location, and trafficking of receptors in living cells. The chemical, physical, and pharmacological properties of the probe remain essential. Here, we describe (1) the preparation of a specific probe for NMDAR GluN2B receptor by conjugation of fluorescein to an ifenprodil-based ligand, (2) an in vitro functional assay by calcium imaging for GluN2B binding and inhibition evaluation of the probe, and (3) the labeling and confocal imaging of GluN2B in DS-red labeled living cortical neurons.

Faecal chitinase 3-like 1 is a reliable marker as accurate as faecal calprotectin in detecting endoscopic activity in adult patients with inflammatory bowel diseases

BACKGROUND

Faecal biomarkers are emerging tools in the assessment of mucosal healing in inflammatory bowel diseases (IBDs).

AIM

To evaluate the accuracy of faecal chitinase 3-like 1(CHI3L1) compared to calprotectin in detecting endoscopic activity in IBD.

METHODS

Overall, 86 IBD adults underwent colonoscopy consecutively and prospectively, with Crohn's disease Endoscopic Index of Severity (CDEIS) or Mayo endoscopic subscore calculation for ulcerative colitis, and stool collection. Faecal calprotectin was measured using quantitative immunochromatographic testing. Faecal CHI3L1 was quantified by ELISA. CHI3L1 cut-off value was determined using a receiver-operating curve.

RESULTS

In 54 Crohn's disease patients, faecal CHI3L1 (ρ = 0.70, P < 0.001) and calprotectin (ρ = 0.74, P < 0.001) levels correlated with CDEIS and were significantly increased in patients with endoscopic ulceration. In patients with ileal Crohn's disease, faecal CHI3L1 seemed to be better correlated with CDEIS than faecal calprotectin (ρ = 0.78 vs. ρ = 0.62, P < 0.001 for both). CHI3L1 > 15 ng/g detected endoscopic ulceration in Crohn's disease with a sensitivity of 100% and a specificity of 63.6%, compared to faecal calprotectin > 250 μg/g showing a sensitivity of 90.5% and a specificity of 59.1%. In 32 ulcerative colitis patients, faecal CHI3L1 and calprotectin levels correlated with Mayo endoscopic subscore (ρ = 0.44 and 0.61, respectively, P < 0.001 for both) and were significantly increased in ulcerative colitis patients with endoscopic activity. In ulcerative colitis patients, faecal CHI3L1 > 15 ng/g predicted endoscopic activity with a sensitivity of 81.8% and a specificity of 80.0%, compared to faecal calprotectin>250 μg/g showing a sensitivity of 86.4% and a specificity of 80.0%.

CONCLUSION

Faecal CHI3L1 is a reliable biomarker in detecting endoscopic activity in IBD.

Endoscopic Factors Influencing Fecal Calprotectin Value in Crohn's Disease

BACKGROUND AND AIMS

Fecal calprotectin [fcal] is a biomarker of Crohn's disease [CD] endoscopic activity. Identifying the endoscopic situations in which fcal is less reliable remains unexplored. We aimed to determine the endoscopic factors influencing fcal level in CD.

METHODS

Overall, 53 CD patients consecutively and prospectively underwent colonoscopy, with CD Endoscopic Index of Severity [CDEIS] calculation and stool collection. Fcal was measured using a quantitative immunochromatographic test. Correlation analysis was done with Pearson statistics.

RESULTS

Fcal was correlated with CDEIS [0.66, p < 0.001]. In univariate analysis, fcal was correlated with the affected surface [0.65, p < 0.001] and the ulcerated surface [0.47, p < 0.001]. Fcal was significantly associated with ulceration depth, with median fcal of 867.5 µg/g, 1251.0 µg/g, and 1800.0 µg/g, in patients presenting with non-ulcerated lesions, superficial ulcerations [SU], and deep ulcerations [DU], respectively. Lesion locations did not influence fcal. In multivariate analysis, fcal was associated with affected surface [p = 0.04] and the presence of CD lesions. Moreover, fcal increased with the ulceration depth [p = 0.03]. However, ulcerated surface and CD location did not affect fcal. Using a receiver operating characteristic [ROC] curve, we showed that fcal of 400 µg/g was the best compromise between sensitivity [0.76] and specificity [0.77], whereas fcal ≥ 200 µg/g was highly sensitive [0.86] to detect SU or DU.

CONCLUSIONS

Fcal is a very reliable biomarker to detect endoscopic ulcerations in CD. We suggest repeating measurement in case of intermediary results [200-400 µg/g] in daily practice. Fcal level is mostly influenced by the presence of CD lesions [even non-ulcerated], in a depth-related manner and by the affected surface.

Diffusion-weighted magnetic resonance imaging is effective to detect ileocolonic ulcerations in Crohn's disease

BACKGROUND

Magnetic resonance entero-colonography enables accurate assessment of ileocolonic Crohn's disease, but the need for bowel cleansing and rectal enema limits considerably its use in daily practice.

AIM

We evaluated the accuracy of diffusion-weighted magnetic resonance entero-colonography with neither bowel cleansing nor rectal enema to assess endoscopic activity.

METHODS

Forty-four Crohn's disease patients underwent prospectively and consecutively diffusion-weighted magnetic resonance entero-colonography [with apparent diffusion coefficient (ADC) and Clermont score calculation] and ileocolonoscopy [with Crohn's Disease Endoscopic Index of Severity (CDEIS) and Simplified Endoscopic score for Crohn's Disease (SES-CD) calculation].

RESULTS

Mean ADC was inversely correlated with total CDEIS (ρ = -0.40; P = 0.0067) and total SES-CD (ρ = -0.33; P = 0.032). Considering the 194 segments, ADC was inversely correlated with segmental CDEIS (-0.48; P < 0.001) and segmental SES-CD (-0.44; P < 0.001). ADC values were lower in segments with deep ulcers (1.30 ± 0.23) or superficial ulcerations (1.75 ± 0.64) than in non-ulcerated segments (2.15 ± 0.5) (P = 0.001). Using a receiver operating curve, we determined that segmental ADC <1.42 detected endoscopic deep ulcerations with sensitivity = 0.91 and specificity = 0.83 (Area under the curve = 0.84; P < 0.001). Segmental ADC <1.88 detected endoscopic superficial ulcerations with sensitivity = 0.64 and specificity = 0.75. The segmental ADC values decreased when the ulcerations size increased (P = 0.0001). Clermont score correlated with ileal CDEIS (0.63; P < 0.05) and ileal SES-CD (0.58; P < 0.05). Clermont score was higher in ulcerated segments (23.3 ± 8.4) than in non-ulcerated segments (12.4 ± 10.0) (P = 0.006) and increased with ulcers size (P = 0.012). Clermont score >18.9 detected ulcerations with sensitivity = 0.79 and specificity = 0.73.

CONCLUSION

Diffusion-weighted magnetic resonance entero-colonography using apparent diffusion coefficient and Clermont score was effective to indirectly detect endoscopic ulcerations in ileocolonic Crohn's disease.

Disruption of dopaminergic transmission remodels tripartite synapse morphology and astrocytic calcium activity within substantia nigra pars reticulata

The substantia nigra pars reticulata (SNr) is a major output nucleus of the basal ganglia circuitry particularly sensitive to pathological dopamine depletion. Indeed, hyperactivity of SNr neurons is known to be responsible for some motor disorders characteristic of Parkinson's disease. The neuronal processing of basal ganglia dysfunction is well understood but, paradoxically, the role of astrocytes in the regulation of SNr activity has rarely been considered. We thus investigated the influence of the disruption of dopaminergic transmission on plastic changes at tripartite glutamatergic synapses in the rat SNr and on astrocyte calcium activity. In 6-hydroxydopamine-lesioned rats, we observed structural plastic changes of tripartite glutamatergic synapses and perisynaptic astrocytic processes. These findings suggest that subthalamonigral synapses undergo morphological changes that accompany the pathophysiological processes of Parkinson's disease. The pharmacological blockade of dopaminergic transmission (with sulpiride and SCH-23390) increased astrocyte calcium excitability, synchrony and gap junction coupling within the SNr, suggesting a functional adaptation of astrocytes to dopamine transmission disruption in this output nucleus. This hyperactivity is partly reversed by subthalamic nucleus high-frequency stimulation which has emerged as an efficient symptomatic treatment for Parkinson's disease. Therefore, our results demonstrate structural and functional reshaping of neuronal and glial elements highlighting a functional plasticity of neuroglial interactions when dopamine transmission is disrupted.

Iron overload accelerates neuronal amyloid-β production and cognitive impairment in transgenic mice model of Alzheimer's disease

Iron dyshomeostasis is proving increasingly likely to be involved in the pathology of Alzheimer's disease (AD); yet, its mechanism is not well understood. Here, we investigated the AD-related mechanism(s) of iron-sulfate exposure in vitro and in vivo, using cultured primary cortical neurons and APP/PS1 AD-model mice, respectively. In both systems, we observed iron-induced disruptions of amyloid precursor protein (APP) processing, neuronal signaling, and cognitive behavior. Iron overload increased production of amyloidogenic KPI-APP and amyloid beta. Further, this APP misprocessing was blocked by MK-801 in vitro, suggesting the effect was N-methyl-D-aspartate receptor (NMDAR) dependent. Calcium imaging confirmed that 24 hours iron exposure led to disrupted synaptic signaling by augmenting GluN2B-containing NMDAR expression-GluN2B messenger RNA and protein levels were increased and promoting excessing extrasynaptic NMDAR signaling. The disrupted GluN2B expression was concurrent with diminished expression of the splicing factors, sc35 and hnRNPA1. In APP/PS1 mice, chronic iron treatment led to hastened progression of cognitive impairment with the novel object recognition discrimination index, revealing a deficit at the age of 4 months, concomitant with augmented GluN2B expression. Together, these data suggest iron-induced APP misprocessing and hastened cognitive decline occur through inordinate extrasynaptic NMDAR activation.

Reciprocal disruption of neuronal signaling and Aβ production mediated by extrasynaptic NMDA receptors: a downward spiral

It is becoming increasingly clear that aberrant neuronal activity can be the cause and the result of amyloid beta production. Synaptic activation facilitates non-amyloidogenic processing of amyloid precursor protein (APP) and cell survival, primarily through synaptic NMDA receptors (NMDARs) and perhaps specifically those containing GluN2A-subunits. In contrast, extrasynaptic and GluN2B-containing NMDARs promote beta-secretase cleavage of APP into amyloid-beta (Aβ). The opposing nature of these NMDAR populations is reflected in their control over cell survival and death pathways. Subtle changes in glutamate homeostasis may shift the balance between these pathways and could play a role in Alzheimer's disease (AD). Indeed, Aβ production, regional loss of brain connectivity and neurodegeneration correlate with neuronal activity in AD patients. From another perspective, Aβ oligomers (Aβo) alter neuronal signaling through several mechanisms involving NMDARs and intracellular calcium mishandling. While Aβo affect multiple receptors, GluN2B-NMDARs have emerged as primary mediators of altered synaptic plasticity and neurotoxicity. Memantine and its successor, NitroMemantine, are efficient at blocking or reversing the deleterious actions of Aβo largely due to their selectivity for extrasynaptic NMDARs. Recently, Aβo were shown to trigger astrocytic release of glutamate to the extrasynaptic space where it activates NMDARs to promote further Aβ production and synaptic depression. Combined with the reciprocal regulation between neuronal activity and Aβ production, extrasynaptic glutamate release adds to a maladaptive model and ultimately results in synaptotoxicity and neurodegeneration of AD. Extrasynaptic NMDAR antagonists remain as a promising therapeutic avenue by interfering with this cascade.

Diffusion-weighted magnetic resonance imaging in ileocolonic Crohn's disease: validation of quantitative index of activity

OBJECTIVES

Magnetic resonance imaging (MRI) allows accurate assessment of Crohn's disease (CD), but requires gadolinium injection. Diffusion-weighted (DW)-MRI yields comparable performances in small bowel CD. We compared the accuracy of DW-MR enterocolonography (MREC) and the magnetic resonance index of activity (MaRIA), and performed an external validation of the Clermont score in assessing inflammation in CD.

METHODS

This was an observational prospective study of a single-center cohort. A total of 130 CD patients underwent consecutively MREC with gadolinium injection and DWI sequences between July 2011 and December 2012.

RESULTS

Of the 848 evaluated segments (small bowel=352, colon/rectum=496), 175 (20.6%) were active (small bowel=111, colon/rectum=64) defined as MaRIA ≥7. Using a receiver operating characteristic (ROC) curve, we determined an apparent coefficient of diffusion (ADC) threshold of 1.9 × 10(-3) mm(2)/s that yielded a sensitivity and a specificity in discriminating active from nonactive CD of 96.9% and 98.1%, respectively, for the colon/rectum, and 85.9% and 81.6%, respectively, for the ileum. ADC was better correlated to MaRIA ≥7 than related contrast enhancement obtained with injected sequences (P<0.001). The Clermont score (=1.646 × bowel thickness-1.321 × ADC+5.613 × edema+8.306 × ulceration+5.039) was highly correlated with the MaRIA (rho=0.99) in ileal CD but not in colonic CD (rho <0.80). Interobserver agreement was high with regard to ADC measurement (correlation >0.9, P<0.001, and concordance >0.9, P<0001).

CONCLUSIONS

DW-MREC is a reliable tool to assess inflammation in colonic (ADC) and ileal (Clermont score) CD and its use in daily practice would avoid gadolinium injection.

Nematodes associated with damage in oilseed rape: new data on the biology and geographical distribution of Meloidogyne artiellia

For several years, patches of plants presenting deficiencies in growth have been observed in fields cultivated with oilseed rape. Over 3 years, 57 pairs of damaged and undamaged plants were sampled from cultivated fields on the Atlantic coast of France and around the Paris basin. Results show that two main species of plant-parasitic nematodes can be associated with the patches, Heterodera cruciferae and Meloidogyne artiellia, and that both species probably do not occur in the same fields and regions. This means that M. artiellia, which is considered as a Mediterranean species causing damage essentially on wheat, is also well adapted to colder climate conditions and can extensively damage oilseed rape. Monitoring the different development stages of M. artiellia in a field cultivated with oilseed rape provided more information about the life cycle and showed that only one generation can develop between the sowing in autumn and April.