Autonomic nervous system involvement in autoimmune encephalitis and paraneoplastic neurological syndromes.

In autoimmune neurological diseases, the autonomic nervous system can be the primary target of autoimmunity (e.g. autoimmune autonomic ganglionopathy), or, more frequently, be damaged together with other areas of the nervous system (e.g. Guillain-Barré syndrome). Patients with autoimmune encephalitis and paraneoplastic neurological syndromes (PNS) often develop dysautonomia; however, the frequency and spectrum of autonomic signs and symptoms remain ill defined except for those scenarios in which dysautonomia is a core feature of the disease. Such is the case of Lambert-Eaton myasthenic syndrome, Morvan syndrome or anti-NMDAR encephalitis; in the latter, patients with dysautonomia have been reported to carry a more severe disease and to retain higher disability than those without autonomic dysfunction. Likewise, the presence of autonomic involvement indicates a higher risk of death due to neurological cause in patients with anti-Hu PNS. However, in anti-Hu and other PNS, as well as in the context of immune checkpoint inhibitors' toxicities, the characterization of autonomic involvement is frequently overshadowed by the severity of other neurological symptoms and signs. When evaluated with tests specific for autonomic function, patients with autoimmune encephalitis or PNS usually show a more widespread autonomic involvement than clinically suggested, which may reflect a potential gap of care when it comes to diagnosing dysautonomia. This review aims to revise the autonomic involvement in patients with autoimmune encephalitis and PNS, using for that purpose an antibody-based approach. We also discuss and provide general recommendations for the evaluation and management of dysautonomia in these patients.

A novel peptide derived from vascular endothelial growth factor prevents amyloid beta aggregation and toxicity.

Amyloid-ß oligomers (Aßo) are the most pathologically relevant Aß species in Alzheimer's disease (AD), because they induce early synaptic dysfunction that leads to learning and memory impairments. In contrast, increasing VEGF (Vascular Endothelial Growth Factor) brain levels have been shown to improve learning and memory processes, and to alleviate Aß-mediated synapse dysfunction. Here, we designed a new peptide, the blocking peptide (BP), which is derived from an Aßo-targeted domain of the VEGF protein, and investigated its effect on Aß-associated toxicity. Using a combination of biochemical, 3D and ultrastructural imaging, and electrophysiological approaches, we demonstrated that BP strongly interacts with Aßo and blocks Aß fibrillar aggregation process, leading to the formation of Aß amorphous aggregates. BP further impedes the formation of structured Aßo and prevents their pathogenic binding to synapses. Importantly, acute BP treatment successfully rescues long-term potentiation (LTP) in the APP/PS1 mouse model of AD, at an age when LTP is highly impaired in hippocampal slices. Moreover, BP is also able to block the interaction between Aßo and VEGF, which suggests a dual mechanism aimed at both trapping Aßo and releasing VEGF to alleviate Aßo-induced synaptic damage. Our findings provide evidence for a neutralizing effect of the BP on Aß aggregation process and pathogenic action, highlighting a potential new therapeutic strategy.

Neurological adverse events of immune checkpoint inhibitors: An update of clinical presentations, diagnosis, and management.

The use of immune checkpoint inhibitors (ICIs) has represented a major advance in cancer treatment. By enhancing endogenous immune responses to destroy cancer cells, ICIs can cause immune-related adverse events (irAEs), with possible involvement of any organ system. IrAEs are frequent, particularly those involving the skin or the endocrine system, and usually completely reversible after temporary immunosuppression, while neurological irAEs (n-irAEs) are relatively rare, often severe, and they carry a considerable risk of mortality and long-term disability. They usually affect the peripheral nervous system, mainly manifesting as myositis, polyradiculoneuropathy, or cranial neuropathy, and, less frequently, involve the central nervous system, causing encephalitis, meningitis, or myelitis. Although somehow reminiscent of the disorders that neurologists are familiar to deal with in their daily practice, n-irAEs are characterized by distinctive features from their idiopathic counterparts; for instance, myositis may have a predominant oculo-bulbar involvement reminiscent of myasthenia gravis and frequently associates with myocarditis; peripheral neuropathy, although often resembling Guillain-Barré syndrome, usually responds to corticosteroids. Remarkably, several associations between the neurological phenotype and the type of ICIs or the type of cancer have emerged in the last few years, and the growing administration of ICIs in patients with neuroendocrine cancers has led to an increased number of reports of paraneoplastic neurological syndromes (triggered or worsened by ICIs). This review aims to update current knowledge regarding the clinical presentation of n-irAEs. We also discuss the essential parts of the diagnostic approach, and we provide general recommendations for the management of these disorders.

Sleep decreases neuronal activity control of microglial dynamics in mice.

Microglia, the brain-resident immune cells, are highly ramified with dynamic processes transiently contacting synapses. These contacts have been reported to be activity-dependent, but this has not been thoroughly studied yet, especially in physiological conditions. Here we investigate neuron-microglia contacts and microglia morphodynamics in mice in an activity-dependent context such as the vigilance states. We report that microglial morphodynamics and microglia-spine contacts are regulated by spontaneous and evoked neuronal activity. We also found that sleep modulates microglial morphodynamics through Cx3cr1 signaling. At the synaptic level, microglial processes are attracted towards active spines during wake, and this relationship is hindered during sleep. Finally, microglial contact increases spine activity, mainly during NREM sleep. Altogether, these results indicate that microglial function at synapses is dependent on neuronal activity and the vigilance states, providing evidence that microglia could be important for synaptic homeostasis and plasticity.

Immunomodulation in the acute phase of autoimmune encephalitis.

Autoimmune encephalitides constitute an emerging group of diseases for which the diagnosis and management may be challenging, and are usually associated with antibodies against neuroglial antigens used as biomarkers. In this review, we aimed to clarify the diagnostic approach to patients with encephalitis of suspected autoimmune origin in order to initiate early immunotherapy, and to summarize the evidence of current immunotherapies and alternative options assessed for refractory cases. Currently, the general therapeutic approach consists of steroids, IVIG, and/or plasma exchange as first-line medications, which should be prescribed once a diagnosis of possible autoimmune encephalitis is established. For patients not responding to these treatments, rituximab and cyclophosphamide are used as second-line immunotherapy. Additionally, alternative therapies, chiefly tocilizumab and bortezomib, have been reported to be useful in particularly refractory cases. Although the aforementioned approach with first and second-line immunotherapy is widely accepted, the best therapeutic strategy is still unclear since most available evidence is gathered from retrospective non-controlled studies. Moreover, several predictors of good long-term prognosis have been proposed such as response to first-line therapies, modified Rankin score lesser than 4 at the worst neurologic status, no need for admission in intensive care unit, and early escalation to second-line immunotherapy. Thus, the lack of solid evidence underlines the necessity of future well-conducted trials addressing both the best therapeutic regimen and the outcome predictors, but since autoimmune encephalitides have a relatively low incidence, international collaborations seem imperative to reach a reasonable study population size.

Combined analysis of MGMT methylation and dynamic-susceptibility-contrast MRI for the distinction between early and pseudo-progression in glioblastoma patients.

INTRODUCTION: Currently, no single diagnostic modality allows the distinction between early progression (EP) and pseudo-progression (Psp) in glioblastoma patients. Herein we aimed to identify the characteristics associated with EP and Psp, and to analyze their diagnostic value alone and in combination. MATERIAL AND METHODS: We reviewed the clinical, conventional magnetic resonance imaging (MRI), and molecular characteristics (MGMT promoter methylation, IDH mutation, and EGFR amplification) of glioblastoma patients who presented an EP (n=59) or a Psp (n=24) within six months after temozolomide radiochemotherapy. We analyzed relative cerebral blood volume (rCBV) and relative vessel permeability on K2 maps (rK2) in a subset of 33 patients using dynamic-susceptibility-contrast MRI. RESULTS: In univariate analysis, EP was associated with neurological deterioration, higher doses of dexamethasone, appearance of a new enhanced lesion, subependymal enhancement, higher rCBV and rK2 values. Psp occurred earlier after radiotherapy completion and was associated with IDH1 R132H mutation, and MGMT methylation. In multivariate analysis, rCBV, rK2, and MGMT methylation status were independently associated with EP and Psp. All patients with a methylated MGMT promoter and a low rCBV (<1.75) were classified as Psp while all patients with an unmethylated MGMT promoter and a high rCBV (≥1.75) were classified as EP. Among patients with discordant MGMT methylation and rCBV characteristics, higher rK2 values tended to be associated with EP. CONCLUSION: Combined analysis of MGMT methylation, rCBV and vessel permeability on K2 maps seems helpful to distinguish EP from Psp. A prospective study is warranted to confirm these results.

EEG analysis in anti-NMDA receptor encephalitis: Description of typical patterns.

OBJECTIVE: To describe different electroencephalogram (EEG) patterns and epileptic features in patients with anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE), their timeline in the course of the disease, their correlation with clinical data and outcome. METHODS: We retrospectively analyzed EEG recordings between November 2007 and June 2016 in 24 consecutive patients. RESULTS: Three EEG patterns were described: Excessive Beta Activity range 14-20 Hz (EBA) in 71% of patients, Extreme Delta Brush (EDB) in 58% and Generalized Rhythmic Delta Activity (GRDA) in 50%. They followed a chronological organization in the course of the disease: EBA appeared first, followed by EDB and then GRDA, as the median time of appearance for EBA, EDB and GRDA was respectively 10, 16.5 and 21.5 days. The presence of GRDA was strongly associated with concomitant abnormal movements (p < 0.001). CONCLUSION: This study focuses on EEG and epileptic abnormalities in anti-NMDARE. Beyond EDB that were already reported (Schmitt et al., 2012), GRDA seems to be a very frequent pattern. Its rhythmic aspect should not be misinterpreted as seizure or status epilepticus, to avoid antiepileptic treatments intensification. SIGNIFICANCE: This study comforts the importance of EEG in anti-NMDARE, with a better description of EEG abnormalities for a better treatment management.

Movement disorders in autoimmune encephalitis and paraneoplastic neurological syndromes.

Movement disorders are extremely common and diverse in autoimmune encephalitis (AE) and paraneoplastic neurological syndromes (PNS). They can sometimes represent the main neurological disorder of a given patient, or just be part of a larger neurological syndrome. Early diagnosis of AE or PNS is essential, as the associated abnormal movements can be effectively treated with immunomodulators. Nevertheless, the diagnosis is often delayed because of the large number of differential diagnoses (infections, metabolic disorders, genetic and degenerative diseases) and because the semiology of abnormal movements arising during AE and PNS is often not well known. However, there are highly specific clinical features, depending on the associated autoantibodies, age and gender of the patient, and associated cancers. Such features are likely to rely on specific mechanisms, the knowledge of which could lead to new therapeutic proposals. Also, the growing body of work on AE and PNS provides a better understanding of the links between immunity and neuronal degeneration, and immunity and genetic specificities. Thus, the purpose of this article is to present the current knowledge and different subtypes of movement disorders associated with AE and PNS, as well as the mechanisms that can lead to neuronal dysfunction.

Autoimmune encephalitis and psychiatric disorders.

Autoimmune encephalitis (AE) refers to a rare, newly described, group of diseases associated with specific circulating autoantibodies directed against neuronal proteins used as biomarkers of the disease. Characterization of the associated autoantibodies present in the patients' cerebrospinal fluid (CSF) and/or sera can differentiate the various AE subgroups, which have specific clinical presentations and prognoses, and is therefore essential for proposing appropriate treatments. As psychiatric symptoms may predominate at the onset or over the course of these diseases, the diagnosis is frequently delayed. Yet, patients' prognoses depend on the speed with which the disease is detected, identified and managed. A wide range of neuropsychiatric symptoms is observed according to the patient's AE subgroup, and some are highly suggestive of an immune origin and should be recognized as such by physicians. Because the presence of pronounced psychiatric symptoms drives patients to psychiatric institutions, which can hinder the diagnosis, physicians need to be aware of AE and propose the detection of autoantibodies as early as possible to provide optimal medical care to such patients. In fact, the description of AE subgroups over the past decade has allowed the present overview of their incidence in psychiatric diseases and some general guidelines for the management of these patients.

Long-term impact of temozolomide on 1p/19q-codeleted low-grade glioma growth kinetics.

Although upfront temozolomide (TMZ) has been widely-used to treat 1p/19q-codeleted diffuse low-grade gliomas (LGG), its long-term impact on the growth kinetics of these tumors has not been determined. Based on serial magnetic resonance images we retrospectively evaluated the evolution of the mean tumor diameter (MTD) in 36 progressive 1p/19q-codeleted LGG treated with upfront TMZ. After TMZ onset, all but two patients (94.4%) presented a progressive MTD decrease that lasted for a median duration of 23 months (range 3-114). In 10 patients (27%) MTD regrowth occurred during TMZ treatment and in 22 patients (66%) after TMZ discontinuation. In these patients, median time to MTD regrowth after TMZ discontinuation was 12 months (range 1-88). The rate of MTD regrowth at 3 and 5 years after TMZ onset was 77 and 94%, respectively. Time to tumor progression (TTP) based on volumetric analysis was shorter than TTP based on Response Assessment in Neuro-Oncology (RANO) bidimensional criteria (23 vs. 35 months, p = 0.05) and shorter than time to next oncological treatment (23 vs. 46 months, p = 0.001). In 10 patients (27%), absence of volumetric analysis led to continue TMZ for a median of 10 cycles after MTD had started to regrow. Volumetric analysis is important to precisely assess chemotherapy efficacy in 1p/19q-codeleted LGG, identify early tumor progression and avoid futile chemotherapy continuation. In the present series, although some long-lasting volumetric responses were observed, most tumors resumed their growth within 3 years after TMZ onset.

[Adult intramedullary gliomas]. / Tumeurs gliales intramédullaires de l'adulte : la série du rapport.

OBJECTIVES: Intramedullary gliomas are rare tumors accounting for less than 4% of all primary central nervous system tumors. The aims of this retrospective multicenter study were to assess their natural outcome as well as management. METHODS AND MATERIALS: We studied 332 patients from 1984 to 2011. Histopathological examination revealed 72% ependymomas (94% were low grade tumors), 24% astrocytomas (29% were high grade tumors), 2.4% mixed gliomas and 1.7% oligodendrogliomas. RESULTS: The mean age at diagnosis was 42.4 years for ependymomas, with male predominance, versus 39.6 years for astrocytomas. Pain was the most common initial presentation. In 20% of cases, astrocytomas were biopsied alone, but more than 80% of ependymomas had surgical resection. Radiotherapy and chemotherapy were reserved for malignant tumors, especially if they were ependymomas. The 5-year survival rate was 76.8% for astrocytomas and 94.5% for ependymomas. Histology, functional status prior to surgery, and tumor grade are among the prognostic factors. CONCLUSION: Our study showed that surgical treatment of gliomas is well codified, at least for ependymomas, but adjuvant treatment continues to play a marginal role in the management even in astrocytomas, which are infiltrative tumors.

Infectious encephalitis: Management without etiological diagnosis 48hours after onset.

INTRODUCTION: The etiological diagnosis of infectious encephalitis is often not established 48hours after onset. We aimed to review existing literature data before providing management guidelines. METHOD: We performed a literature search on PubMed using filters such as "since 01/01/2000", "human", "adults", "English or French", and "clinical trial/review/guidelines". We also used the Mesh search terms "encephalitis/therapy" and "encephalitis/diagnosis". RESULTS: With Mesh search terms "encephalitis/therapy" and "encephalitis/diagnosis", we retrieved 223 and 258 articles, respectively. With search terms "encephalitis and corticosteroid", we identified 38 articles, and with "encephalitis and doxycycline" without the above-mentioned filters we identified 85 articles. A total of 210 articles were included in the analysis. DISCUSSION: Etiological investigations must focus on recent travels, animal exposures, age, immunodeficiency, neurological damage characteristics, and potential extra-neurological signs. The interest of a diagnosis of encephalitis for which there is no specific treatment is also to discontinue any empirical treatments initially prescribed. Physicians must consider and search for autoimmune encephalitis.