Neurocentre Magendie

Bruno BROCHET




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127 publication(s) depuis Janvier 1987:


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12/11/2016 | Brain Behav Immun   IF 5.9
Selective dentate gyrus disruption causes memory impairment at the early stage of experimental multiple sclerosis.
Planche V, Panatier A, Hiba B, Ducourneau EG, Raffard G, Dubourdieu N, Maitre M, Leste-Lasserre T, Brochet B, Dousset V, Desmedt A, Oliet SH, Tourdias T

Abstract:
Memory impairment is an early and disabling manifestation of multiple sclerosis whose anatomical and biological substrates are still poorly understood. We thus investigated whether memory impairment encountered at the early stage of the disease could be explained by a differential vulnerability of particular hippocampal subfields. By using experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis, we identified that early memory impairment was associated with selective alteration of the dentate gyrus as pinpointed in vivo with diffusion-tensor-imaging (DTI). Neuromorphometric analyses and electrophysiological recordings confirmed dendritic degeneration, alteration in glutamatergic synaptic transmission and impaired long-term synaptic potentiation selectively in the dentate gyrus, but not in CA1, together with a more severe pattern of microglial activation in this subfield. Systemic injections of the microglial inhibitor minocycline prevented DTI, morphological, electrophysiological and behavioral impairments in EAE-mice. Furthermore, daily infusions of minocycline specifically within the dentate gyrus were sufficient to prevent memory impairment in EAE-mice while infusions of minocycline within CA1 were inefficient. We conclude that early memory impairment in EAE is due to a selective disruption of the dentate gyrus associated with microglia activation. These results open new pathophysiological, imaging, and therapeutic perspectives for memory impairment in multiple sclerosis.




27/10/2016 | J Neurol Neurosurg Psychiatry
Posterior lobules of the cerebellum and information processing speed at various stages of multiple sclerosis.
Moroso A, Ruet A, Lamargue-Hamel D, Munsch F, Deloire M, Coupe P, Ouallet JC, Planche V, Moscufo N, Meier DS, Tourdias T, Guttmann CR, Dousset V, Brochet B

Abstract:
BACKGROUND: Cerebellar damage has been implicated in information processing speed (IPS) impairment associated with multiple sclerosis (MS) that might result from functional disconnection in the frontocerebellar loop. Structural alterations in individual posterior lobules, in which cognitive functioning seems preponderant, are still unknown. Our aim was to investigate the impact of grey matter (GM) volume alterations in lobules VI to VIIIb on IPS in persons with clinically isolated syndrome (PwCIS), MS (PwMS) and healthy subjects (HS). METHODS: 69 patients (37 PwCIS, 32 PwMS) and 36 HS underwent 3 T MRI including 3-dimensional T1-weighted MRIs. Cerebellum lobules were segmented using SUIT V.3.0 to estimate their normalised GM volume. Neuropsychological testing was performed to assess IPS and main cognitive functions. RESULTS: Normalised GM volumes were significantly different between PwMS and HS for the right (p<0.001) and left lobule VI (p<0.01), left crus I, right VIIb and entire cerebellum (p<0.05 for each comparison) and between PwMS and PwCIS for all lobules in subregions VI and left crus I (p<0.05). IPS, attention and working memory were impaired in PwMS compared with PwCIS. In the whole population of patients (PwMS and PwCIS), GM loss in vermis VI (R2=0.36; p<0.05 when considering age and T2 lesion volume as covariates) were associated with IPS impairment. CONCLUSIONS: GM volume decrease in posterior lobules (especially vermis VI) was associated with reduced IPS. Our results suggest a significant impact of posterior lobules pathology in corticocerebellar loop disruption resulting in automation and cognitive optimisation lack in MS. TRIAL REGISTRATION: Clinicaltrail NCT01207856, NCT01865357; Pre-results.




25/10/2016 | Mult Scler   IF 4.5
Hippocampal microstructural damage correlates with memory impairment in clinically isolated syndrome suggestive of multiple sclerosis.
Planche V, Ruet A, Coupe P, Lamargue-Hamel D, Deloire M, Pereira B, Manjon JV, Munsch F, Moscufo N, Meier DS, Guttmann CR, Dousset V, Brochet B, Tourdias T

Abstract:
OBJECTIVE: We investigated whether diffusion tensor imaging (DTI) could reveal early hippocampal damage and clinically relevant correlates of memory impairment in persons with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). METHODS: A total of 37 persons with CIS, 32 with MS and 36 controls prospectively included from 2011 to 2014 were tested for cognitive performances and scanned with 3T-magnetic resonance imaging (MRI) to assess volumetric and DTI changes within the hippocampus, whole brain volume and T2-lesion load. RESULTS: While there was no hippocampal atrophy in the CIS group, hippocampal fractional anisotropy (FA) was significantly decreased compared to controls. Decrease in hippocampal FA together with increased mean diffusivity (MD) was even more prominent in MS patients. In CIS, hippocampal MD was correlated with episodic verbal memory performance (r = -0.57, p = 0.0002 and odds ratio (OR) = 0.058, 95% confidence interval (CI) = 0.0057-0.59, p = 0.016 adjusted for age, gender, depression and T2-lesion load), but not with cognitive tasks unrelated to hippocampal functions. Hippocampal MD was the only variable discriminating memory-impaired from memory-preserved persons with CIS (area under the curve (AUC) = 0.77, sensitivity = 90.0%, specificity = 70.3%, positive predictive value (PPV) = 52.9%, negative predictive value (NPV) = 95.0%). CONCLUSION: DTI alterations within the hippocampus might reflect early neurodegenerative processes that are correlated with episodic memory performance, discriminating persons with CIS according to their memory status.




15/12/2015 | J Neurol Sci   IF 2.1
Cognitive evaluation by tasks in a virtual reality environment in multiple sclerosis.
Lamargue-Hamel D, Deloire M, Saubusse A, Ruet A, Taillard J, Philip P, Brochet B

Abstract:
BACKGROUND: The assessment of cognitive impairment in multiple sclerosis (MS) requires large neuropsychological batteries that assess numerous domains. The relevance of these assessments to daily cognitive functioning is not well established. Cognitive ecological evaluation has not been frequently studied in MS. OBJECTIVES: The aim of this study was to determine the interest of cognitive evaluation in a virtual reality environment in a sample of persons with MS with cognitive deficits. METHODS: Thirty persons with MS with at least moderate cognitive impairment were assessed with two ecological evaluations, an in-house developed task in a virtual reality environment (Urban DailyCog(R)) and a divided attention task in a driving simulator. Classical neuropsychological testing was also used. RESULTS AND CONCLUSION: Fifty-two percent of the persons with MS failed the driving simulator task and 80% failed the Urban DailyCog(R). Virtual reality assessments are promising in identifying cognitive impairment in MS.




11/09/2015 | Mult Scler   IF 4.5
Efficacy of rituximab in refractory neuromyelitis optica.
Collongues N, Brassat D, Maillart E, Labauge P, Ouallet JC, Carra-Dalliere C, Moreau T, Bourre B, Papeix C, Brochet B, Audoin B, Vukusic S, de Seze J, Marignier R

Abstract:
BACKGROUND: Despite a growing use of rituximab (RTX) in neuromyelitis optica (NMO), data are lacking in patients with refractory NMO (RNMO), defined as cases with at least one relapse during immunosuppressive therapy. OBJECTIVE: The purpose of this study was to assess RTX as a maintenance therapy in RNMO. METHODS: Out of a total of 305 NMO cases from a population-based cohort, 21 RNMO patients received RTX during a mean follow-up period of 31 months. RESULTS: After RTX, 11 patients (52.3%) were relapse free, meaning that 47.7% were refractory to RTX. The mean annualized relapse rate decreased from 1.3 to 0.4 (p<0.001) and median EDSS from 5 to 3 (p=0.02). Body mass index (BMI) was predictive of EDSS worsening. CONCLUSIONS: RTX is an effective and well-tolerated treatment in RNMO. BMI could be a predictive factor for efficacy.




11/09/2015 | Mult Scler   IF 4.5
A 10-year follow-up of the European multicenter trial of interferon beta-1b in secondary-progressive multiple sclerosis.
Kuhle J, Hardmeier M, Disanto G, Gugleta K, Ecsedi M, Lienert C, Amato MP, Baum K, Buttmann M, Bayas A, Brassat D, Brochet B, Confavreux C, Edan G, Farkkila M, Fredrikson S, Frontoni M, D'Hooghe M, Hutchinson M, De Keyser J, Kieseier BC, Kumpfel T, Rio J, Polman C, Roullet E, Stolz C, Vass K, Wandinger KP, Kappos L

Abstract:
OBJECTIVES: To explore long-term effects of treatment and prognostic relevance of variables assessed at baseline and during the European secondary progressive multiple sclerosis (SPMS) trial of interferon beta 1b (IFNB-1b). METHODS: We assessed 362 patients (60% female; median age 41 years; Expanded Disability Status Scale (EDSS): 5.5; 51% randomized to IFNB-1b) for their EDSS and treatment history after 10 years. Non-parametric analysis of covariance (ANCOVA) and multivariate linear regression models were applied. RESULTS: Median EDSS was 6.0 at the end of the randomized controlled trial (RCT), in the IFNB-1b and placebo groups, and 7.0 in long-term follow-up patients (those receiving IFNB-1b in the RCT were 6.5 and those receiving placebo in the RCT were 7.0; p = 0.086). 24 patients (6.6%) were deceased. The EDSS at baseline and the EDSS change during the RCT were the most important predictors of the EDSS 10 years later (partial R2: 0.47). The ability to predict changes in EDSS 10 years after the RCT was limited (R2: 0.12). Magnetic resonance imaging (MRI) measures remained in the predictive models, but explained < 5% of the variability. CONCLUSIONS: The results from this analysis did not provide convincing evidence to support a favorable long-term outcome in those patients allocated IFNB-1b during the RCT, in our SPMS cohort. The progressive stage of the disease remains largely unpredictable by clinical and conventional MRI measures, so better prognostic markers are needed.




Abstract:
BACKGROUND: The independent prognostic value of cerebrospinal fluid analysis in multiple sclerosis is not established. OBJECTIVE: To determine the prognostic value of intrathecal synthesis in a cohort of patients with relapsing-onset MS taking into consideration demographic and imaging parameters. METHODS: In this prospective cohort study conducted from 1993 to 2013, we analyzed the time to confirmed disability (persistent above 6 months) and irreversible disability (persistent for the entire disease course) of two disability milestones, Expanded Disability Status Scale score >/= 4 or 6, and the time to secondary progressive onset in 579 patients with relapsing-onset multiple sclerosis. Demographic parameters (age at onset, gender) and imaging parameters (periventricular lesions) were included in the Cox models. RESULTS: 447 patients (77.2%) had intrathecal synthesis (oligoclonal bands and/or increased immunoglobulin G index value). No statistically significant relation was found between intrathecal synthesis and the time to reach each disability milestone or secondary progressive onset. An age older than 40 years and more than 3 periventricular lesions predicted a worse prognosis. CONCLUSIONS: Cerebrospinal fluid analysis did not predict the time to disability milestones in relapsing-onset multiple sclerosis independently of age and imaging data.




07/2015 | J Neurol   IF 3.4
Isolated tumefactive demyelinating lesions: diagnosis and long-term evolution of 16 patients in a multicentric study.
Siri A, Carra-Dalliere C, Ayrignac X, Pelletier J, Audoin B, Pittion-Vouyovitch S, Debouverie M, Lionnet C, Viala F, Sablot D, Brassat D, Ouallet JC, Ruet A, Brochet B, Taillandier L, Bauchet L, Derache N, Defer G, Cabre P, de Seze J, Lebrun Frenay C, Cohen M, Labauge P

Abstract:
Isolated tumefactive demyelinating lesion (TDL) is a rare disease and a challenging entity especially for the differential diagnosis, biopsy indications, and therapeutic decisions. Long-term evolution is not well known. The objective of the study is to describe clinical and MRI characteristics and long-term follow-up of patients with isolated TDL. We performed a retrospective study including patients (1) with one TDL radiologically defined by a >/=20 mm FLAIR hyperintensity involving the white matter associated with T1 hypointensity that enhanced after gadolinium injection and (2) without any other MS lesion on the first MRI. Tumor, abscess, or other inflammatory diseases (ADEM, Balo's concentric sclerosis, systemic disease) were excluded. Sixteen patients (11 females/5 males) were included. The mean age of onset was 35.7 years (range 20-65). MRI disclosed supratentorial lesions with a mean size of 39.4 mm and usually mild edema/mass effect. Peripheral (mainly open-ring pattern) and central (mainly heterogeneous) enhancement were respectively seen in 9/16 and 11/16 patients. CSF study (n = 15) found oligoclonal bands (OCB) in seven. A cerebral biopsy was performed in 11 cases showing acute inflammatory demyelination. Thirteen patients were treated by pulse steroids with marked improvement in ten. At last clinical follow-up (mean 65.8 months, range 6-181), diagnosis was MS in 5 (31 %), isolated TDL in 10 (63 %) and one patient had a second TDL (6 %). Isolated tumefactive demyelinating lesions are a rare diagnostic entity. After a mean follow-up of 5 years, almost one-third became MS whereas most of the patients had no further event.




03/2015 | AJNR Am J Neuroradiol
MS lesions are better detected with 3D T1 gradient-echo than with 2D T1 spin-echo gadolinium-enhanced imaging at 3T.
Crombe A, Saranathan M, Ruet A, Durieux M, de Roquefeuil E, Ouallet JC, Brochet B, Dousset V, Tourdias T

Abstract:
BACKGROUND AND PURPOSE: In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions. MATERIALS AND METHODS: Fifty-eight patients with MS were prospectively imaged at 3T by using both 2D-spin-echo and 3D-gradient recalled-echo T1WI in random order after the injection of gadolinium. Blinded and independent evaluation was performed by a junior and a senior reader to count gadolinium-enhancing lesions and to characterize their location, size, pattern of enhancement, and the relative contrast between enhancing lesions and the adjacent white matter. Finally, the SNR and relative contrast of gadolinium-enhancing lesions were computed for both sequences by using simulations. RESULTS: Significantly more gadolinium-enhancing lesions were reported on 3D-gradient recalled-echo than on 2D-spin-echo (n = 59 versus n = 30 for the junior reader, P = .021; n = 77 versus n = 61 for the senior reader, P = .017). The difference between the 2 readers was significant on 2D-spin-echo (P = .044), for which images were less reproducible (kappa = 0.51) than for 3D-gradient recalled-echo (kappa = 0.65). Further comparisons showed that there were statistically more small lesions (<5 mm) on 3D-gradient recalled-echo than on 2D-spin-echo (P = .04), while other features were similar. Theoretic results from simulations predicted SNR and lesion contrast for 3D-gradient recalled-echo to be better than for 2D-spin-echo for visualization of small enhancing lesions and were, therefore, consistent with clinical observations. CONCLUSIONS: At 3T, 3D-gradient recalled-echo provides a higher detection rate of gadolinium-enhancing lesions, especially those with smaller size, with a better reproducibility; this finding suggests using 3D-gradient recalled-echo to detect MS activity, with potential impact in initiation, monitoring, and optimization of therapy.




02/2015 | J Neurol   IF 3.4
Presumed tuberculous retrobulbar optic neuritis: a diagnosis challenge.
Aupy J, Vital A, Rougier MB, Gradel A, Meissner W, Marchal C, Penchet G, Brochet B

Abstract: