Natalizumab improves ambulation in relapsing-remitting multiple sclerosis: results from the prospective TIMER study and a retrospective analysis of AFFIRM.

BACKGROUND AND PURPOSE: Impaired ambulation is a prominent disabling symptom of multiple sclerosis and can lead to reduced quality of life. Whether natalizumab, a monoclonal antibody shown to reduce disease activity in relapsing-remitting multiple sclerosis, could impact ambulation performance was examined. METHODS: A prospective open-label study, TIMER, was conducted in natalizumab-naive patients (n = 215). The timed 25-foot walk (T25FW) and timed 100-m walk (T100MW) were assessed at baseline and at weeks 24 and 48 of natalizumab therapy, together with Expanded Disability Status Scale scores. The effects of natalizumab on T25FW performance were also examined in a retrospective analysis of natalizumab-treated patients (n = 627) and placebo control patients (n = 315) from the AFFIRM study. RESULTS: In TIMER, a significant increase from baseline in T25FW speed was seen at week 24 (P = 0.0074) and in T100MW speed at weeks 24 and 48 (both P < 0.001). A greater proportion of patients showed clinically meaningful increases (≥20%) in walking speed on the T100MW (25%) than on the T25FW (13%) at week 48 (P = 0.032). In AFFIRM, natalizumab increased the proportion of patients with ≥20% confirmed improvement in T25FW speed at year 2 by 78% versus placebo (P = 0.0133). CONCLUSIONS: Natalizumab increased walking speed in patients with relapsing-remitting multiple sclerosis. The T100MW may be more sensitive to changes in ambulation capacity than the T25FW, and both tests appear to detect clinically meaningful improvements in ambulatory function.

[Vitamin D tweets light to genes in multiple sclerosis]. / La vitamine D connecte la lumière aux gènes dans la sclérose en plaques.

The relationship between sunlight exposure and the incidence of multiple sclerosis and the understanding of immunomodulatory effects of vitamin D triggered, in recent years, a broad range of investigations. Immunological studies performed in vitro and in vivo have demonstrated how tolerogenic vitamin D can be. Epidemiological studies confirmed an increased incidence of multiple sclerosis in vitamin D deficient subjects and signs of increased disease activity in such MS patients. Although small-scale observational studies have suggested a beneficial impact of vitamin D supplementation on the incidence and severity of multiple sclerosis, large scale clinical trials remain warranted to confirm these preliminary results.

Natalizumab induces a rapid improvement of disability status and ambulation after failure of previous therapy in relapsing-remitting multiple sclerosis.

BACKGROUND: Natalizumab (Tysabri) is a monoclonal antibody that was recently approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). Our primary objective was to analyse the efficacy of natalizumab on disability status and ambulation after switching patients with RRMS from other disease-modifying treatments (DMTs). METHODS: A retrospective, observational study was carried out. All patients (n=45) initiated natalizumab after experiencing at least 1 relapse in the previous year under interferon-beta (IFNB) or glatiramer acetate (GA) treatments. The patients also had at least 1 gadolinium-enhancing (Gd+) lesion on their baseline brain MRI. Expanded Disability Status Scale (EDSS) scores, and performance on the Timed 25-Foot Walk Test and on the Timed 100-Metre Walk Test were prospectively collected every 4 weeks during 44 weeks of natalizumab treatment. Brain MRI scans were performed after 20 and 44 weeks of treatment. RESULTS: Sixty-two per cent of patients showed no clinical and no radiological signs of disease activity, and 29% showed a rapid and confirmed EDSS improvement over 44 weeks of natalizumab therapy. Patients with improvement on the EDSS showed similar levels of baseline EDSS and active T1 lesions, but had a significantly higher number of relapses, and 92% of them had experienced relapse-mediated sustained EDSS worsening in the previous year. A clinically meaningful improvement in ambulation speed was observed in approximately 30% of patients. CONCLUSIONS: These results indicate that natalizumab silences disease activity and rapidly improves disability status and walking performance, possibly through delayed relapse recovery in patients with RRMS who had shown a high level of disease activity under other DMTs.

Patterning Chronic Active Demyelination in Slowly Expanding/Evolving White Matter MS Lesions.

BACKGROUND AND PURPOSE: Slowly expanding/evolving lesions measured by conventional T1-weighted/T2-weighted brain MR imaging may contribute to progressive disability accumulation in MS. We evaluated the longitudinal change in myelin and axonal tissue integrity in white matter slowly expanding/evolving lesions by means of the magnetization transfer ratio and DTI radial diffusivity. MATERIALS AND METHODS: Slowly expanding/evolving lesions were detected within the Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of BIIB033 in Participants With Relapsing Forms of Multiple Sclerosis When Used Concurrently With Avonex (SYNERGY) Phase 2 clinical trial dataset (NCT01864148), comprising patients with relapsing-remitting and secondary-progressive MS (n = 299) with T1-weighted/T2-weighted MR imaging at all trial time points (baseline to week 72). RESULTS: Compared with non-slowly expanding/evolving lesions (areas not classified as slowly expanding/evolving lesion) of baseline nonenhancing T2 lesions, slowly expanding/evolving lesions had a lower normalized magnetization transfer ratio and greater DTI radial diffusivity, both in patients with relapsing-remitting MS (n = 242) and secondary-progressive MS (n = 57, P < .001 for all). Although the changes with time in both the normalized magnetization transfer ratio and DTI radial diffusivity between slowly expanding/evolving lesions and non-slowly expanding/evolving lesions were positively correlated (P < .001), a decrease in the normalized magnetization transfer ratio and a greater increase in DTI radial diffusivity were observed in slowly expanding/evolving lesions versus non-slowly expanding/evolving lesions from baseline to week 72 in relapsing-remitting MS and secondary-progressive MS (P < .001 for all). CONCLUSIONS: Patterns of longitudinal change in the normalized magnetization transfer ratio and DTI radial diffusivity in slowly expanding/evolving lesions were consistent with progressive demyelination and tissue loss, as seen in smoldering white matter MS plaques.

Smartphone-based remote assessment of upper extremity function for multiple sclerosis using the Draw a Shape Test.

OBJECTIVE: Smartphone devices may enable out-of-clinic assessments in chronic neurological diseases. We describe the Draw a Shape (DaS) Test, a smartphone-based and remotely administered test of Upper Extremity (UE) function developed for people with multiple sclerosis (PwMS). This work introduces DaS-related features that characterise UE function and impairment, and aims to demonstrate how multivariate modelling of these metrics can reliably predict the 9-Hole Peg Test (9HPT), a clinician-administered UE assessment in PwMS. APPROACH: The DaS Test instructed PwMS and healthy controls (HC) to trace predefined shapes on a smartphone screen. A total of 93 subjects (HC, n = 22; PwMS, n = 71) contributed both dominant and non-dominant handed DaS tests. PwMS subjects were characterised as those with normal (nPwMS, n = 50) and abnormal UE function (aPwMS, n = 21) with respect to their average 9HPT time (≤ or > 22.7 (s), respectively). L 1-regularization techniques, combined with linear least squares (OLS, IRLS), or non-linear support vector (SVR) or random forest (RFR) regression were investigated as functions to map relevant DaS features to 9HPT times. MAIN RESULTS: It was observed that average non-dominant handed 9HPT times were more accurately predicted by DaS features (r 2 = 0.41, [Formula: see text] 0.05; MAE: 2.08 ± 0.34 (s)) than average dominant handed 9HPTs (r 2 = 0.39, [Formula: see text] 0.05; MAE: 2.32 ± 0.43 (s)), using simple linear IRLS ([Formula: see text] 0.01). Moreover, it was found that the Mean absolute error (MAE) in predicted 9HPTs was comparable to the variability of actual 9HPT times within HC, nPwMS and aPwMS groups respectively. The 9HPT however exhibited large heteroscedasticity resulting in less stable predictions of longer 9HPT times. SIGNIFICANCE: This study demonstrates the potential of the smartphone-based DaS Test to reliably predict 9HPT times and remotely monitor UE function in PwMS.

[Monoclonal antibodies in neurology]. / Les anticorps monoclonaux en neurologie.

Since their inception in the 1970's, monoclonal antibody therapies became increasingly efficient and common in numerous medical conditions and their use in neurology has been boosted during the last couple of years with the rise of natalizumab (Tysabri). Furthermore, if most monoclonal antibodies currently assessed in neurologic conditions remain considered as experimental, they may soon become first-line approved treatments in a broad range of neuromuscular and demyelinating diseases. Since the introduction of new therapies is likely to unravel specific adverse events and sui generis iatrogenic disorders, it is important to be able to recognize the side-effects of monoclonal antibodies delivered for neurological or non-neurological diseases.

[When HIV gets into the brain]. / Lorsque le VIH atteint le système nerveux central.

Besides opportunistic infections, direct or indirect HIV-mediated lesions of cerebral vascular or neural cells can also occur during the natural course of HIV infection. The main non-infectious complications of HIV are cerebral lymphomas, cerebrovascular disorders, HIV dementia and myelitis.

[HIV-related infections of the brain]. / Les infections encéphaliques liées au VIH.

During the natural course of human immunodeficiency virus infection, central nervous system insults are very common. They can consist of infectious complications, consequently to the collapse of the patient's immune system. Alternatively, direct or indirect HIV-mediated lesions of cerebral vascular or neural cells can also occur. It is crucial to detect HIV-related infectious complications since their prognosis will depend on early and accurate treatments. The diagnosis is generally made by means of magnetic resonance imaging and lumbar puncture.

[Depression and neuroplasticity]. / Dépression et neuroplasticité.

The effect of antidepressants cannot be explained by the classical monoaminergic theory. In particular, that model does not explain the delay in clinical response with antidepressants. Many hypotheses have been developed to understand the mechanism of action of antidepressants, each of them involving the regulation of different receptors. In parallel, functional brain imaging and neurobiological techniques have revealed specific neuroanatomical lesions in affective disorders. Depression in particular is associated with a neuronal loss in specific brain regions. These anatomical changes are reduced after antidepressant treatment. In the last decade, a new pathophysiological concept of affective disorders has emerged, integrating preferentially molecular and cellular antidepressant-induced changes leading to rehabilitation of synaptic activity. In the present review, we will summarize recent crucial data that establish the link between depression and neuroplasticity.

[Therapeutic armamentarium in neurology: the birth of a new era]. / L'arsenal thérapeutique en neurologie: une nouvelle ère voit le jour.

The field of neurology was long infamous for a lack of therapeutic options. How many of you have once thought: "Neurologists don't cure the disease, they admire it". But those days have passed into history, and the field is now vibrant with new treatments and hope even for patients with the worst neurodegenerative diseases. We summarized in the present review the latest major advances in therapeutic principles and practice for some of the most frequent chronic neurological disorders such as headaches, epilepsy, multiple sclerosis, dementias, Parkinson's disease, sleep/wake disturbances and peripheral neuropathies. We cannot cure or prevent, but we can now halt or control symptoms and disease progression to provide physical and psychological relief, and a better quality of life for patients who suffer from these otherwise devastating neurological conditions.

[Clinical case of the month. Cerebrovascular accident related to arterial brachiocephalic trunk stenosis]. / Le cas clinique du mois. Accident ischémique cérébral sur sténose du tronc artériel brachiocéphalique.

The authors report the case of a 47-year old man, admitted for syncope and left-sided motor deficit. Diagnostic investigations revealed a right middle cerebral artery embolic stroke, secondary to a critical stenosis of the arterial brachiocephalic trunk, harboring a floating thrombus. The treatment options for occlusive lesions of the brachiocephalic trunk are discussed, as well as the optimal delay between stroke and brain revascularization.

The anti-epileptic drug levetiracetam reverses the inhibition by negative allosteric modulators of neuronal GABA- and glycine-gated currents.

1. In this study in vitro and in vivo approaches were combined in order to investigate if the anti-epileptic mechanism(s) of action of levetiracetam (LEV; Keppra) may involve modulation of inhibitory neurotransmission. 2. GABA- and glycine-gated currents were studied in vitro using whole-cell patch-clamp techniques applied on cultured cerebellar granule, hippocampal and spinal neurons. Protection against clonic convulsions was assessed in vivo in sound-susceptible mice. The effect of LEV was compared with reference anti-epileptic drugs (AEDs): carbamazepine, phenytoin, valproate, clonazepam, phenobarbital and ethosuximide. 3. LEV contrasted the reference AEDs by an absence of any direct effect on glycine-gated currents. At high concentrations, beyond therapeutic relevance, it induced a small reduction in the peak amplitude and a prolongation of the decay phase of GABA-gated currents. A similar action on GABA-elicited currents was observed with the reference AEDs, except ethosuximide. 4. These minor direct effects contrasted with a potent ability of LEV (EC(50)=1 - 10 microM) to reverse the inhibitory effects of the negative allosteric modulators zinc and beta-carbolines on both GABA(A) and glycine receptor-mediated responses. 5. Clonazepam, phenobarbital and valproate showed a similar ability to reverse the inhibition of beta-carbolines on GABA-gated currents. Blockade of zinc inhibition of GABA responses was observed with clonazepam and ethosuximide. Phenytoin was the only AED together with LEV that inhibited the antagonism of zinc on glycine-gated currents and only clonazepam and phenobarbital inhibited the action of DMCM. 6. LEV (17 mg kg(-1)) produced a potent suppression of sound-induced clonic convulsions in mice. This protective effect was significantly abolished by co-administration of the beta-carboline FG 7142, from a dose of 5 mg kg(-1). In contrast, the benzodiazepine receptor antagonist flumazenil (up to 10 mg kg(-1)) was without any effect on the protection afforded by LEV. 7. The results of the present study suggest that a novel ability to oppose the action of negative modulators on the two main inhibitory ionotropic receptors may be of relevance for the anti-epileptic mechanism(s) of action of LEV.

Astroglia-released factor with negative allosteric modulatory properties at the GABA A receptor.

We have previously shown, using whole-cell patch-clamp techniques, that astrocytes release a negative allosteric modulator of the gamma-aminobutyric acid type A receptor (GABAA receptor) with beta-carboline-like properties, thus, likely to act at the benzodiazepine site. Here, using patch-clamp and binding techniques, we confirm that the low-molecular-weight fraction of astroglia-conditioned medium (ACM lmf) contains a factor(s) that negatively modulates GABAA-receptor function. This factor, like beta-carbolines, enhances the specific binding of [35S]t-butyl bicyclophosphorothionate (TBPS) to adult rat cortical membranes in the presence of GABA. However, it fails to interact with various ligands of the benzodiazepine (BZD) site of the GABAA receptor ([3H]flunitrazepam, [3H]Ro 15-1788 and [3H]Ro 15-4513). The question of the actual binding site of the astroglia-derived factor on the GABAA receptor, thus, remains open and can be addressed only after the purification of the active molecule(s) of ACM Imf has been completed, and a labeled form of the endogenous ligand becomes available. Taken together, however, the data suggest that type 1 astrocytes are able to modulate the effects of the main inhibitory neurotransmission in the central nervous system.

Developmental regulation of neuroligand-induced responses in cultured oligodendroglia.

Using whole-cell patch-clamp techniques, we show that oligosphere-derived oligodendrocyte progenitor cells (OP) display GABA-, glutamate-, 5-HT-, glycine- and acetylcholine-gated inward currents. When OP differentiate into oligodendrocytes (ODC), the amplitude of peak currents elicited by saturating concentrations of these transmitters decreases except for 5-HT. Intracellular Ca2+ concentration changes induced by microperfusion of glutamate, 5-HT, TRH, met-enkephalin and substance P were monitored using a fluo-3-based calcium imaging system. When OP cells differentiate into ODC, a global decrease of the proportion of responding cells is observed. During type-2 astrocytes commitment, this proportion decreases for 5-HT, TRH- and metenkephalin stimulations whereas it remains constant for substance P and glutamate. These data demonstrate a development regulation of neurotransmitter- and neuropeptide-induced responses within the oligodendroglial lineage.

Beta-carbolines induce apoptotic death of cerebellar granule neurones in culture.

Apart from its role in fast inhibitory transmission, only neurotrophic effects have been reported following activation of the GABAA receptor. Here, we show that n-butyl-beta-carboline-3-carboxylate and n-methyl-beta-carboline-3-carboxamide, which are negative allosteric modulators of the GABAA receptor acting at the benzodiazepine site, are neurotoxic for cerebellar granule neurones in culture. The beta-carboline-induced neuronal death is apoptotic since DNA internucleosomal fragmentation was induced and the neurotoxicity could be prevented by inhibitors of mRNA or protein synthesis. As GABA and benzodiazepine ligands (diazepam and Ro 15-1788) protect cerebellar granule cells against beta-carboline-induced toxicity, these data raise the possibility that the interaction between the beta-carbolines and the GABAA receptor is the triggering event leading to neuronal apoptosis.

Diazepam-insensitive GABAA receptors on postnatal spiral ganglion neurones in culture.

Using dissociated spiral ganglion cell cultures obtained from 3-day-old rat cochlea, we investigated the response of auditory neurones to gamma-aminobutyric acid (GABA) using patch-clamp techniques. In our recording conditions, GABA elicited inward currents in > 95% of the neurones which reversed around 0 mV. Similar inward currents were measured using isoguvacin, a specific agonist of GABAA receptors. GABA-gated currents were reversibly inhibited by the channel blocker picrotoxin and the GABA competitive antagonist bicuculline. These functional GABAA receptors are characterized by an insensitivity to benzodiazepines and a relatively high sensitivity to beta-carbolines and barbiturates. These results show that the GABAA receptor pharmacological properties of spiral ganglion neurones are close to those of cerebellar granule cells.

Oligodendrocytes: from development to demyelinated lesion repair.

Spontaneous but incomplete remyelination is observed after a demyelinating lesion. We know since ten years now that oligodendrocyte progenitors, (OP) and totipotent neural stem cells remain present in the central nervous system of adult mammals. Moreover, these OP are more likely the cellular source of remyelinating cells. Here, we intend to demonstrate that the understanding of the myelination process that occurs during development might lead to new treatments aimed at inducing remyelination: stimulation of resident OP or grafting of purified perinatal OP.

Neurotransmitter-mediated regulation of CNS myelination: a review.

In addition to treatments aimed at preventing or limiting damage to myelin and oligodendrocytes, there is a crucial need for repair strategies in human demyelinating disorders. There is increasing evidence that besides growth factors, neurotransmitters can regulate different steps of the oligodendrogliogenesis. The present review on neurotransmitter receptor expression and function in the oligodendrocyte lineage emphasizes the concept that in this lineage cell proliferation and differentiation can be controlled through the modulation of the functional state of channel proteins and receptors, such as the delayed K+ rectifier, the AMPA/kainate, dopamine or muscarinic receptors, and, most likely, others yet to be found. We anticipate that a better understanding of the neurotransmitter-mediated neuronal oligodendroglial communication network opens prospects in the field of central nervous system (CNS) myelin repair, allowing the recruitment of the myelinating machinery that is known to remain present but quiescent in the CNS of multiple sclerosis patients.

[Clinical case of the month. Report of a case of antiphospholipid syndrome]. / Le cas clinique du mois. A propos d'un cas de syndrome des antiphospholipides.

This article reports a case of Anton-Babinski syndrome, due to right middle cerebral artery thrombosis and attributed to a likely primary antiphospholipid syndrome. It is always difficult to diagnose the latter, especially in the case of our patient who had a past history of multiple venous thromboses but also a heterozygosity for the mutation of the factor V of Leyden. We reviewed the literature dedicated to the prothrombotic events linked to the presence of these antiphospholipid antibodies: the lupus anticoagulant and the anticardiolipin antibodies.