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Cortical demyelinated lesions are frequent and widespread in chronic multiple sclerosis (MS) patients, and may contribute to disease progression. Inflammation and related oxidative stress have been proposed as central mediators of cortical damage, yet meningeal and cortical inflammation is not specific to MS, but also occurs in other diseases. The first aim of this study was to test whether cortical demyelination was specific for demyelinating CNS diseases compared to other CNS disorders with prominent meningeal and cortical inflammation. The second aim was to assess whether oxidative tissue damage was associated with the extent of neuroaxonal damage. We studied a large cohort of patients diagnosed with demyelinating CNS diseases and non-demyelinating diseases of autoimmune, infectious, neoplastic or metabolic origin affecting the meninges and the cortex. Included were patients with MS, acute disseminated encephalomyelitis (ADEM), neuromyelitis optica (NMO), viral and bacterial meningoencephalitis, progressive multifocal leukoencephalopathy (PML), subacute sclerosing panencephalitis (SSPE), carcinomatous and lymphomatous meningitis and metabolic disorders such as extrapontine myelinolysis, thus encompassing a wide range of adaptive and innate cytokine signatures. Using myelin protein immunohistochemistry, we found cortical demyelination in MS, ADEM, PML and extrapontine myelinolysis, whereby each condition showed a disease-specific histopathological pattern. Remarkably, extensive ribbon-like subpial demyelination was only observed in MS, thus providing an important pathogenetic and diagnostic cue. Cortical oxidative injury was detected in both demyelinating and non-demyelinating CNS disorders. Our data demonstrate that meningeal and cortical inflammation alone accompanied by oxidative stress are not sufficient to generate the extensive subpial cortical demyelination found in MS, but require other MS-specific factors. CA extern

Enhanced glial fibrillary acidic protein (GFAP) expression occurs in most diseases of the central nervous system. Thus far, little is known about the effect that GFAP exerts on astrocyte cell signaling. In the present study, we observed that silencing GFAP expression in isolated astrocytes leads to enhanced CCL2 and CXCL10 release, whereas overexpression of GFAP in astrocytes results in a significantly reduced CXCL10 release in vitro. Additionally, we analyzed transgenic mice carrying a full-length copy of the wild-type human GFAP gene. We demonstrate that a persistent GFAP increase alters the astrocytic cell signaling profile, thereby protecting oligodendrocytes, myelin and, subsequently, axons from cuprizone-induced demyelination. Our study revealed that reduced CXCL10 mRNA was accompanied by reduced NF-κB expression in astrocytes. Furthermore, analysis of human tissue from a patient with Alexander disease showed NF-κB activation in astrocytes to be almost completely absent. Our findings indicate that regulation of GFAP expression in astrocytes is crucial for astrocyte signaling and function. Understanding the role of the cytoskeletal protein, GFAP is thus of importance as it is highly regulated in diseases of the central nervous system.

Ein 70-jahriger Ex-Box-Profi erlitt bei manifester Demenz einen Bolustod. Bei der neuropathologischen Untersuchung konnte das Vorliegen einer CTE Stadium III–IV sowohl im formalinfixierten Hirngewebe als auch im archivierten Blockmaterial immunhistochemisch nachgewiesen werden. Ob die Erkrankung bei einer schweren Straftat 27 Jahre prafinal zu einer mutmaslichen Minderung der Schuldfahigkeit beigetragen haben kann, bleibt spekulativ.

Background Quinoline-3-carboxamides, such as laquinimod, ameliorate CNS autoimmunity in patients and reduce tumor cell metastasis experimentally. Previous studies have focused on the immunomodulatory effect of laquinimod on myeloid cells. The data contained herein suggest that quinoline-3-carboxamides improve the immunomodulatory and anti-tumor effects of NK cells by upregulating the adhesion molecule DNAX accessory molecule-1 (DNAM-1). Methods We explored how NK cell activation by laquinimod inhibits CNS autoimmunity in experimental autoimmune encephalomyelitis (EAE), the most utilized model of MS, and improves immunosurveillance of experimental lung melanoma metastasis. Functional manipulations included in vivo NK and DC depletion experiments and in vitro assays of NK cell function. Clinical, histological, and flow cytometric read-outs were assessed. Results We demonstrate that laquinimod activates natural killer (NK) cells via the aryl hydrocarbon receptor and increases their DNAM-1 cell surface expression. This activation improves the cytotoxicity of NK cells against B16F10 melanoma cells and augments their immunoregulatory functions in EAE by interacting with CD155+ dendritic cells (DC). Noteworthy, the immunosuppressive effect of laquinimod-activated NK cells was due to decreasing MHC class II antigen presentation by DC and not by increasing DC killing. Conclusions This study clarifies how DNAM-1 modifies the bidirectional crosstalk of NK cells with CD155+ DC, which can be exploited to suppress CNS autoimmunity and strengthen tumor surveillance. Open-Access-Publikationsfonds 2019

Aims: In Wilson disease (WD), T2/T2*-weighted (T2*w) MRI frequently shows hypointensity in the basal ganglia that is suggestive of paramagnetic deposits. It is currently unknown whether this hypointensity is related to copper or iron deposition. We examined the neuropathological correlate of this MRI pattern, particularly in relation to iron and copper concentrations. Methods: Brain slices from nine WD and six control cases were investigated using a 7T-MRI system. High resolution T2*w images were acquired and R2* parametric maps were reconstructed using a multi-gradient recalled echo sequence. R2* was measured in the globus pallidus (GP) and the putamen. Corresponding histopathological sections containing the lentiform nucleus were examined using Turnbull iron staining, and double staining combining Turnbull with immunohistochemistry for macrophages or astrocytes. Quantitative densitometry of the iron staining as well as copper and iron concentrations were measured in the GP and putamen and correlated to R2* values. Results: T2*w hypointensity in the GP and/or putamen was apparent in WD cases and R2* values correlated with quantitative densitometry of iron staining. In WD, iron and copper concentrations were increased in the putamen compared to controls. R2* was correlated with the iron concentration in the GP and putamen whereas no correlation was observed for the copper concentration. Patients with more pronounced pathological severity in the putamen displayed increased iron concentration, which correlated with an elevated number of iron-containing macrophages. Conclusions: T2/T2*w hypointensity observed in vivo in the basal ganglia of WD patients is related to iron rather than copper deposits.

Multiple sclerosis (MS) is the most common cause for sustained disability in young adults, yet treatment options remain very limited. Although numerous therapeutic approaches have been effective in rodent models of experimental autoimmune encephalomyelitis (EAE), only few proved to be beneficial in patients with MS. Hence, there is a strong need for more predictive animal models. Within the past decade, EAE in the common marmoset evolved as a potent, alternative model for MS, with immunological and pathological features resembling more closely the human disease. However, an often very rapid and severe disease course hampers its implementation for systematic testing of new treatment strategies. We here developed a new focal model of EAE in the common marmoset, induced by myelin oligodendrocyte glycoprotein (MOG) immunization and stereotactic injections of proinflammatory cytokines. At the injection site of cytokines, confluent inflammatory demyelinating lesions developed that strongly resembled human MS lesions. In a proof-of-principle treatment study with the immunomodulatory compound laquinimod, we demonstrate that targeted EAE in marmosets provides a promising and valid tool for preclinical experimental treatment trials in MS research.

Remyelination capacity decreases with age in adult mice, but data comparing remyelination capacity after toxic demyelination in developing mice versus adult mice are not available. We treated 3-week-old and adult C57BL/6 mice with cuprizone for 1 to 5 weeks and studied demyelination/remyelination and cellular reactions in the corpus callosum and motor cortex by histology, immunohistochemistry, and electron microscopy. We compared results between the 2 treated groups and age-matched controls. In juvenile mice, significant demyelination was detectable in the corpus callosum on Week 2 and in the motor cortex on Week 5. Oligodendrocyte loss, microglial activation, and acute axonal damage peaked on Week 2. Increased numbers of oligodendrocyte precursor cells were evident on Week 1, and remyelination was detectable on Week 3. Juvenile mice showed more rapid demyelination than adult mice, which may be related to greater vulnerability of oligodendrocytes, lower myelin content, or dose-dependent cuprizone effects. Earlier activation of microglia and proliferation of oligodendrocyte precursor cells probably contributed to accelerated remyelination and less pronounced axonal damage. Our data indicate that oligodendroglial regeneration and remyelination are enhanced in the maturing rodent brain compared with the young-adult rodent brain.

Despite its functional importance and well known clinical impact in Multiple Sclerosis (MS), the cerebellum has only received significant attention over the past few years. It is now established that the cerebellum plays a key role not only in various sensory-motor networks, but also in cognitive-behavioural processes, domains primarily affected in patients with MS. Evidence from histopathological and magnetic resonance imaging (MRI) studies on cerebellar involvement in MS is increasingly available, however linking these pathological findings with clinical dysfunction remains challenging. There are promising advances in technology that are likely to improve the detection of pathological changes within the cerebellum, which may elucidate how pathology relates to disability.

Cortical demyelination is a widely recognized hallmark of multiple sclerosis (MS) and correlate of disease progression and cognitive decline. The pathomechanisms initiating and driving gray matter damage are only incompletely understood. Here, we determined the infiltrating leukocyte subpopulations in 26 cortical demyelinated lesions of biopsied MS patients and assessed their contribution to cortical lesion formation in a newly developed mouse model. We find that conformation-specific anti-myelin antibodies contribute to cortical demyelination even in the absence of the classical complement pathway. T cells and natural killer cells are relevant for intracortical type 2 but dispensable for subpial type 3 lesions, whereas CCR2+ monocytes are required for both. Depleting CCR2+ monocytes in marmoset monkeys with experimental autoimmune encephalomyelitis using a novel humanized CCR2 targeting antibody translates into significantly less cortical demyelination and disease severity. We conclude that biologics depleting CCR2+ monocytes might be attractive candidates for preventing cortical lesion formation and ameliorating disease progression in MS. Electronic supplementary material The online version of this article (doi:10.1007/s00401-017-1706-x) contains supplementary material, which is available to authorized users.

Objectives The etiology and genetic susceptibility of primary central nervous system vasculitis (PCNSV) are still unclear. Patients and methods We analyzed the DNA of 25 Caucasian patients with PCNSV for human leucocyte antigen genes HLA-A, HLA-B, HLA-DRB1, and HLA-DQB1, respectively. HLA-frequencies of the 25 patients with PCNSV were compared with HLA-frequencies of matched Caucasian controls. Results No statistically significant associations were found for HLA-B, HLA-DR1 and HLA-DQB1 variant. In the PCNSV group, only the HLA-A*69 variant was found more often than expected statistically. Conclusion The results of this study indicate a potential association of HLA marker with PCNSV in Caucasian patients. Further studies are needed to elucidate the role of genes within the human major histocompatibility complex in the pathogenesis of this angiopathy.

Objectives To compare clinical features and outcome, imaging characteristics, biopsy results and laboratory findings in a cohort of 69 patients with suspected or diagnosed primary central nervous system vasculitis (PCNSV) in adults; to identify risk factors and predictive features for PCNSV. Patients and methods We performed a case-control-study including 69 patients referred with suspected PCNSV from whom 25 were confirmed by predetermined diagnostic criteria based on biopsy (72%) or angiography (28%). Forty-four patients turned out to have 15 distinct other diagnoses. Clinical and diagnostic data were compared between PCNSV and Non-PCNSV cohorts. Results Clinical presentation was not able to discriminate between PCNSV and its differential diagnoses. However, a worse clinical outcome was associated with PCNSV (p = 0.005). Biopsy (p = 0.004), contrast enhancement (p = 0.000) or tumour-like mass lesion (p = 0.008) in magnetic resonance imaging (MRI), intrathecal IgG increase (p = 0.020), normal Duplex findings of cerebral arteries (p = 0.022) and conventional angiography (p = 0.010) were able to distinguish between the two cohorts. Conclusion In a cohort of 69 patients with suspected PCNSV, a large number (64%) was misdiagnosed and partly received treatment, since mimicking diseases are very difficult to discriminate. Clinical presentation at manifestation does not help to differentiate PCNSV from its mimicking diseases. MRI and cerebrospinal fluid analysis are unlikely to be normal in PCNSV, though unspecific if pathological. Cerebral angiography and biopsy must complement other diagnostics when establishing the diagnosis in order to avoid misdiagnosis and mistreatment. Clinical trial registration German clinical trials register: http://drks-neu.uniklinik-freiburg.de/drks_web/ , Unique identifier: DRKS00005347.

Subpial cortical demyelination (SCD) accounts for the greatest proportion of demyelinated cortex in multiple sclerosis (MS). SCD is already found in biopsy cases with early MS and in marmosets with experimental autoimmune encephalomyelitis (EAE), but the pathogenesis of SCD is not well understood. The objective of this study was to investigate whether and, if so, which meningeal inflammatory cells were associated with early SCD in marmosets with EAE. Immunohistochemistry was performed to analyze brain samples from eight control animals and eight marmosets immunized with myelin oligodendrocyte glycoprotein. Meningeal T, B and plasma cells were quantified adjacent to SCD, normal-appearing EAE cortex (NAC) and control marmoset cortex. SCD areas appeared mostly hypocellular with low-grade microglial activation. In marmosets with EAE, meninges adjacent to SCD showed significantly increased T cells paralleled by elevated plasma cells, but unaltered B cell numbers compared with NAC. The elevation of meningeal T and plasma cells was a specific finding topographically associated with SCD, as the meninges overlying NAC displayed similarly low T, B and plasma cell numbers as control cortex. These findings suggest that local meningeal T and plasma cell infiltration contributes to the pathogenesis of SCD in marmosets with EAE.

Cerebral cortex shows a high endogenous propensity for remyelination. Yet, widespread subpial cortical demyelination (SCD) is a common feature in progressive multiple sclerosis (MS) and can already be found in early MS. In the present study, we compared oligodendroglial loss in SCD in early and chronic MS. Furthermore, we addressed in an experimental model whether repeated episodes of inflammatory SCD could alter oligodendroglial repopulation and subsequently lead to persistently demyelinated cortical lesions. NogoA+ mature oligodendrocytes and Olig2+ oligodendrocyte precursor cells were examined in SCD in patients with early and chronic MS, normal-appearing MS cortex, and control cortex as well as in the rat model of repeated targeted cortical experimental autoimmune encephalomyelitis (EAE). NogoA+ and Olig2+ cells were significantly reduced in SCD in patients with chronic, but not early MS. Repeated induction of SCD in rats resulted only in a transient loss of NogoA+, but not Olig2+ cells during the demyelination phase. This phase was followed by complete oligodendroglial repopulation and remyelination, even after four episodes of demyelination. Our data indicate efficient oligodendroglial repopulation in subpial cortical lesions in rats after repeated SCD that was similar to early, but not chronic MS cases. Accordingly, four cycles of experimental de- and remyelination were not sufficient to induce sustained remyelination failure as found in chronic cortical MS lesions. This suggests that alternative mechanisms contribute to oligodendrocyte depletion in chronic cortical demyelination in MS. Electronic supplementary material The online version of this article (doi:10.1007/s00401-014-1260-8) contains supplementary material, which is available to authorized users.

Neuromyelitis optica (NMO) is a chronic, mostly relapsing inflammatory demyelinating disease of the CNS characterized by serum anti-aquaporin 4 (AQP4) antibodies in the majority of patients. Anti-AQP4 antibodies derived from NMO patients target and deplete astrocytes in experimental models when co-injected with complement. However, the time course and mechanisms of oligodendrocyte loss and demyelination and the fate of oligodendrocyte precursor cells (OPC) have not been examined in detail. Also, no studies regarding astrocyte repopulation of experimental NMO lesions have been reported. We utilized two rat models using either systemic transfer or focal intracerebral injection of recombinant human anti-AQP4 antibodies to generate NMO-like lesions. Time-course experiments were performed to examine oligodendroglial and astroglial damage and repair. In addition, oligodendrocyte pathology was studied in early human NMO lesions. Apart from early complement-mediated astrocyte destruction, we observed a prominent, very early loss of oligodendrocytes and oligodendrocyte precursor cells (OPCs) as well as a delayed loss of myelin. Astrocyte repopulation of focal NMO lesions was already substantial after 1 week. Olig2-positive OPCs reappeared before NogoA-positive, mature oligodendrocytes. Thus, using two experimental models that closely mimic the human disease, our study demonstrates that oligodendrocyte and OPC loss is an extremely early feature in the formation of human and experimental NMO lesions and leads to subsequent, delayed demyelination, highlighting an important difference in the pathogenesis of MS and NMO.

In this multicentre study involving eight European centres, we characterized the spatial pattern of functional connectivity (FC) in the sensorimotor network from 61 right-handed patients with multiple sclerosis (MS) and 74 age-matched healthy subjects assessed with the use of functional magnetic resonance imaging (fMRI) and a simple motor task of their right dominant hand. FC was investigated by using: (i) voxel-wise correlations between the left sensorimotor cortex (SMC) and any other area in the brain; and (ii) bivariate correlations between time series extracted from several regions of interest (ROIs) belonging to the sensorimotor network. Both healthy controls and MS patients had significant FC between the left SMC and several areas of the sensorimotor network, including the bilateral postcentral and precentral gyri, supplementary motor area, middle frontal gyri, insulae, secondary somatosensory cortices, thalami, and right cerebellum. Voxel-wise assessment of FC revealed increased connectivity between the left SMC and the right precentral gyrus, right middle frontal gyrus (MFG) and bilateral postcentral gyri in MS patients as compared with controls. ROI analysis also showed a widespread pattern of altered connectivity, characterized by increased FC between the right MFG, the left insula and the right inferior frontal gyrus in comparison with many regions of the sensorimotor network. These results provide further evidence for increased bihemispheric contributions to motor control in patients with MS relative to healthy controls. They further suggest that multicentre fMRI studies of FC changes are possible, and provide a potential imaging biomarker for use in experimental therapeutic studies directed at enhancing adaptive plasticity in the disease.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system which responds to anti-inflammatory treatments in the early disease phase. However, the pathogenesis of the progressive disease phase is less well understood, and inflammatory as well as neurodegenerative mechanisms of tissue damage are currently being discussed. This review summarizes current knowledge on the interrelation between inflammation, demyelination, and neurodegeneration derived from the study of human autopsy and biopsy brain tissue and experimental models of MS.

We investigated the effect of laquinimod on inflammatory demyelination, axonal damage, cytokine profiles and migratory capacities of lymphocytes in C57BL/6 mice with active EAE induced with MOG(35-55) peptide. The mice were treated at disease induction and after disease onset. Spinal cords were assessed histologically. Cytokines and adhesive properties were analyzed in splenocytes. Preventive and therapeutic laquinimod treatment reduced clinical signs, inflammation, and demyelination. VLA-4-mediated adhesiveness and pro-inflammatory cytokines such as IL-17 were down-regulated in treated animals. Within lesions, treated mice showed similar axonal densities, but less acute axonal damage than controls. Laquinimod might thus protect myelin and axons by decreasing pro-inflammatory cytokines and impairing the migratory capacity of lymphocytes.

Short-term adaptation indicates the attenuation of the functional MRI (fMRI) response during repeated task execution. It is considered to be a physiological process, but it is unknown whether short-term adaptation changes significantly in patients with brain disorders, such as multiple sclerosis (MS). In order to investigate short-term adaptation during a repeated right-hand tapping task in both controls and in patients with MS, we analyzed the fMRI data collected in a large cohort of controls and MS patients who were recruited into a multi-centre European fMRI study. Four fMRI runs were acquired for each of the 55 controls and 56 MS patients at baseline and 33 controls and 26 MS patients at 1-year follow-up. The externally cued (1 Hz) right hand tapping movement was limited to 3 cm amplitude by using at all sites (7 at baseline and 6 at follow-up) identically manufactured wooden frames. No significant differences in cerebral activation were found between sites. Furthermore, our results showed linear response adaptation (i.e. reduced activation) from run 1 to run 4 (over a 25 minute period) in the primary motor area (contralateral more than ipsilateral), in the supplementary motor area and in the primary sensory cortex, sensory-motor cortex and cerebellum, bilaterally. This linear activation decay was the same in both control and patient groups, did not change between baseline and 1-year follow-up and was not influenced by the modest disease progression observed over 1 year. These findings confirm that the short-term adaptation to a simple motor task is a physiological process which is preserved in MS.

We performed a prospective multi-centre study using functional magnetic resonance imaging (fMRI) to better characterize the relationships between clinical expression and brain function in patients with multiple sclerosis (MS) at eight European sites (56 MS patients and 60 age-matched, healthy controls). Patients showed greater task-related activation bilaterally in brain regions including the pre- and post-central, inferior and superior frontal, cingulate and superior temporal gyri and insula (P < 0.05, all statistics corrected for multiple comparisons). Both patients and healthy controls showed greater brain activation with increasing age in the ipsilateral pre-central and inferior frontal gyri (P < 0.05). Patients, but not controls, showed greater brain activation in the anterior cingulate gyrus and the bilateral ventral striatum (P < 0.05) with less hand dexterity. An interaction between functional activation changes in MS and age was found. This large fMRI study over a broadly selected MS patient population confirms that movement for patients demands significantly greater cognitive 'resource allocation' and suggests age-related differences in brain responses to the disease. These observations add to evidence that brain functional responses (including potentially adaptive brain plasticity) contribute to modulation of clinical expression of MS pathology and demonstrate the feasibility of a multi-site functional MRI study of MS.

Multiple sclerosis (MS) is the most common cause for sustained disability in young adults, yet treatment options remain very limited. Although numerous therapeutic approaches have been effective in rodent models of experimental autoimmune encephalomyelitis (EAE), only few proved to be beneficial in patients with MS. Hence, there is a strong need for more predictive animal models. Within the past decade, EAE in the common marmoset evolved as a potent, alternative model for MS, with immunological and pathological features resembling more closely the human disease. However, an often very rapid and severe disease course hampers its implementation for systematic testing of new treatment strategies. We here developed a new focal model of EAE in the common marmoset, induced by myelin oligodendrocyte glycoprotein (MOG) immunization and stereotactic injections of proinflammatory cytokines. At the injection site of cytokines, confluent inflammatory demyelinating lesions developed that strongly resembled human MS lesions. In a proof‐of‐principle treatment study with the immunomodulatory compound laquinimod, we demonstrate that targeted EAE in marmosets provides a promising and valid tool for preclinical experimental treatment trials in MS research.

My research project in the field of olfaction is based on a theoretical model of early olfactory processing that we used to design a psychophysical study. The theoretical model suggests that regions in the olfactory bulb, so called modules, can be viewed as single characters of an encoding alphabet for the detailed understanding of epitope maps in the olfactory bulb. For the module generation, non-negative matrix factorization (NMF) was applied to [C14]-deoxyglucose-uptake-images of the olfactory bulb of rats. In the current study, I am seeking for a correlation between the odor quality of compounds and their corresponding modules. So the hypothesis to be tested here is: Odorants that activate similar patterns of modules are likely to be perceived as being more similar than others. To test this hypothesis, I performed a double-blind psychophysical study on humans. For the study, I selected a choice of 18 odorants which can be assigned to five different modules (of the underlying model of nine modules). Each odorant was diluted such that it was at the lower detection threshold of a panel of test subject. The odorants were offered to human subjects in all possible 171 pairwise combinations and the subjects were asked to rate whether or not the odorants smell similiar. All subjects at least participated in one session, most subjects performed two trails of 30 different odorant pairs. The pairs were randomly assigned and the bottles were coded, so the participants had no knowledge about the contents of each bottle. A subset of participants was measured twice the same session. First results show, that there is a significant correlation between the perceived odor similiarity and the proposed modules, i.e. my study lends color to his hypothesis. Thus, similarities of odor substances may be predicted just by using similarities measured on these modules. The study has been performed with three groups of participants independently (21 and 26 subjects with 60 pairs, and 11 subjects that were exposed to 30 pairs twice) . The correlation could be observed in all three trials.

Subpial cortical demyelination (SCD) accounts for the greatest proportion of demyelinated cortex in multiple sclerosis (MS). SCD is already found in biopsy cases with early MS and in marmosets with experimental autoimmune encephalomyelitis (EAE), but the pathogenesis of SCD is not well understood. The objective of this study was to investigate whether and, if so, which meningeal inflammatory cells were associated with early SCD in marmosets with EAE. Immunohistochemistry was performed to analyze brain samples from eight control animals and eight marmosets immunized with myelin oligodendrocyte glycoprotein. Meningeal T, B and plasma cells were quantified adjacent to SCD, normal‐appearing EAE cortex (NAC) and control marmoset cortex. SCD areas appeared mostly hypocellular with low‐grade microglial activation. In marmosets with EAE, meninges adjacent to SCD showed significantly increased T cells paralleled by elevated plasma cells, but unaltered B cell numbers compared with NAC. The elevation of meningeal T and plasma cells was a specific finding topographically associated with SCD, as the meninges overlying NAC displayed similarly low T, B and plasma cell numbers as control cortex. These findings suggest that local meningeal T and plasma cell infiltration contributes to the pathogenesis of SCD in marmosets with EAE.

Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system. Traditionally, demyelinating lesions in the white matter have been regarded as the most important pathological feature in MS, but recent pathological and imaging studies confirmed substantial changes in grey matter and normal-appearing white matter. MS lesions are characterized by inflammation, demyelination, axonal damage and astrogliosis. During early MS lesion formation acute axonal injury is extensive and correlates with inflammation. In addition to focal lesions, diffuse wide-spread changes including neuroaxonal degeneration and compartmentalized inflammation are likely to contribute to increasing disability in progressive MS. Neuromyelitis optica (NMO) is classically characterized by severe transverse myelitis and optic neuritis, but brain lesions are also present in the majority of NMO patients. The discovery of the NMO-specific antibody demonstrated that NMO is a disease entity distinct from MS. This antibody binds to aquaporin-4 expressed in astrocytes and ependymal cells. NMO lesions are characterized by inflammation, demyelination, axonal damage and a marked loss of aquaporin-4. Early NMO lesions demonstrate a pronounced humoral inflammatory response and astrocytic cell death with loss of aquaporin-4, followed by inflammatory demyelination and axonal damage. These recent findings contribute to a better understanding of different mechanisms leading to inflammatory demyelination.

Clinical–pathological correlations have been investigated using magnetic resonance‐based techniques in patients with multiple sclerosis arguably more intensively than for any other neurological disease. However, despite impressive accomplishments, consensus regarding a common pathology underlying clinical behaviours in patients with relapsing–remitting (RR), secondary progressive (SP) and primary progressive (PP) multiple sclerosis has been elusive. In part this may have been due to the singular focus on pathological changes in the white matter. Attention has been directed to the multifocal inflammatory lesions in white matter because their pathology appeared to offer an explanation for the characteristic RR course of the earlier stages of the disease in most patients. However, focal white matter lesions do not lead to disability progression in a simple way, particularly for PP multiple sclerosis, which is characterised by a relatively low white matter lesion load. White matter lesions alone also do not easily explain cognitive dysfunction in multiple sclerosis, evidence of which can be found in 40–65% of patients, including even a proportion of those presenting with otherwise apparently clinically isolated focal syndromes (Feinstein et al ., 1992). Pathological changes in grey matter provide an alternative basis for hypotheses concerning clinicopathological correlations in multiple sclerosis. Although recognised by early neuropathologists (Greenfield and King, 1936), the significance of inflammation and demyelination in grey matter was not widely appreciated. Recent histopathological studies have re‐examined grey matter involvement and suggest that the extent of pathology is potentially substantial (Peterson et al ., 2001; Cifelli et al ., 2002). In theory, a powerful approach to understanding the clinical significance of this pathology would be to follow changes in vivo , when they can be related directly with symptoms and signs. While magnetic resonance imaging is relatively insensitive to focal lesions in grey matter, it can measure grey matter volumes to high …

Laquinimod is a small, novel, orally active, well-tolerated molecule that significantly reduced gadolinium-enhancing lesions in patients with multiple sclerosis (MS). Orally administered laquinimod was found to be present within the central nervous system (CNS) in both healthy mice and mice with experimental autoimmune encephalomyelitis (EAE). Laquinimod inhibits development of both acute and chronic EAE. Furthermore, laquinimod minimizes inflammation, demyelination and axonal damage in MOG-induced EAE in mice treated at disease induction and following clinical disease onset. In vitro, laquinimod down-regulates secretion of pro-inflammatory cytokines and enhances production of anti-inflammatory cytokines from peripheral blood mononuclear cells (PBMCs) derived from healthy subjects and untreated relapsing remitting (RR) MS patients. Additionally, patients treated with laquinimod demonstrate up-regulation of brain-derived neurotrophic factor (BDNF) in the serum. In conclusion, treatment with laquinimod is effective in reducing inflammation, demyelination and axonal damage.

Gray matter demyelination is frequent and extensive in most patients with multiple sclerosis (MS) and has recently received much attention in neuropathologic and imaging studies. Gray matter lesions show distinct pathologic features that make their detection difficult with conventional imaging techniques. Thus, despite their high prevalence, their impact on clinical symptoms has not been defined well so far. This review focuses on recent information from pathologic and imaging studies and summarizes our current knowledge on cortical pathology derived from human and experimental studies.

Multiple sclerosis (MS) lesions are histopathologically characterized by inflammation, demyelination/remyelination, axonal damage and gliosis. Animal experimental and in vitro studies suggest that sex hormones influence the immune system and contribute to the increased likelihood in women of developing MS. However, a variety of studies have also shown that remyelination is more marked in female rodents or that female sex hormones are beneficial for myelin repair. To determine whether gender influences the histopathology of MS lesions, we compared the extent of inflammation, axonal damage and remyelination in MS lesions of female and male MS patients. We observed no differences in the composition of inflammatory infiltrates, axonal damage or cortical pathology. Similar numbers of oligodendroglial progenitor cells and mature oligodendrocytes were present in MS lesions. Remyelination is slightly, but not significantly, more extensive in women than men in early MS lesions. The absence of significant differences in lesion pathology between female and male MS patients might be explained by a lack of a gender influence, but also might be due to the limited number of tissue samples available for histopathological analysis.

In this multicenter study, we used dynamic causal modeling to characterize the abnormalities of effective connectivity of the sensorimotor network in 61 patients with multiple sclerosis (MS) compared with 74 age‐matched healthy subjects. We also investigated the correlation of such abnormalities with findings derived from structural MRI. In a subgroup of subjects, diffusion tensor (DT) MRI metrics of the corpus callosum and the left corticospinal tract (CST) were also assessed. MS patients showed increased effective connectivity relative to controls between: (a) the left primary SMC and the left dorsal premotor cortex (PMd), (b) the left PMd and the supplementary motor areas (SMA), (c) the left secondary sensorimotor cortex (SII) and the SMA, (d) the right SII and the SMA, (e) the left SII and the right SII, and (f) the right SMC and the SMA. MS patients had relatively reduced effective connectivity between the left SMC and the right cerebellum. No interaction was found between disease group and center. Coefficients of altered connectivity were weakly correlated with brain T2 LV, but moderately correlated with DT MRI‐measured damage of the left CST. In conclusion, large multicenter fMRI studies of effective connectivity changes in diseased people are feasible and can facilitate studies with sample size large enough for robust outcomes. Increased effective connectivity in the patients for the simple motor task suggests local network modulation contributing to enhanced long‐distance effective connectivity in MS patients. This extends and generalizes previous evidence that enhancement of effective connectivity may provide an important compensatory mechanism in MS. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.

Multiple sclerosis is the most common chronic, disabling central nervous system disease in young adults, characterized by inflammatory demyelinating white matter lesions with glial scar formation and axonal loss. Lately, evidence has accumulated that large areas of grey matter are affected in multiple sclerosis patients.Findings in post-mortem brain tissue support the notion that cortical demyelination is frequent and extensive, especially in patients with chronic multiple sclerosis. Cortical lesions differ from white matter lesions with respect to inflammatory cell infiltration, gliosis, and remyelination. Thus, differences in cortical and white matter lesion pathogenesis have been proposed. Experimental models suggest a decisive role for antimyelin antibodies in cortical demyelination. Topical studies focus on damage to neurons, dendrites, and synapses in cortical multiple sclerosis lesions. Improved imaging techniques for the detection of cortical lesions are currently developed and will provide the basis for future clinicopathological correlative studies.In summary, recent years have opened our eyes to the extensive grey matter involvement in multiple sclerosis. Studies on the pathogenesis of cortical demyelination, cortical damage, and repair will elucidate basic principles of multiple sclerosis lesion formation. However, more sensitive imaging tools are required to study the impact of cortical lesions on clinical symptoms, disability, and disease progression.

With expanding potential clinical applications of functional magnetic resonance imaging (fMRI) it is important to test how reliable different measures of fMRI activation are between subjects and sessions and between centres. This study compared variability across 17 patients with multiple sclerosis (MS) and 22 age-matched healthy controls (HC) in 5 European centres performing an fMRI block design with hand tapping. We recruited subjects from sites using 1.5 T scanners from different manufacturers. 5 healthy volunteers also were studied at each of 4 of the centres. We found that reproducibility between runs and sessions for single individuals was consistently much greater than between individuals. There was greater run-to-run variability for MS patients than for HC. Measurements of maximum signal change (MSC) appeared to provide higher reproducibility within individuals and greater sensitivity to differences between individuals than region of interest (ROI) suprathreshold voxel counts. The variability in measurements between centres was not as great as that between individuals. Consistent with these observations, we estimated that power should not be reduced substantially with use of multi-, as opposed to single-, centre study designs with similar numbers of subjects. Multi-centre interventional studies in which fMRI is used as an outcome measure thus appear practical even when implemented in conventional clinical environments.

Motor control demands coordinated excitation and inhibition across distributed brain neuronal networks. Recent work has suggested that multiple sclerosis (MS) may be associated with impairments of neuronal inhibition as part of more general progressive impairments of connectivity. Here, we report results from a prospective, multi-centre fMRI study designed to characterise the changes in patients relative to healthy controls during a simple cued hand movement task. This study was conducted at eight European sites using 1.5 Tesla scanners. Brain deactivation during right hand movement was assessed in 56 right-handed patients with relapsing-remitting or secondary progressive MS without clinically evident hand impairment and in 60 age-matched, healthy subjects. The MS patients showed reduced task-associated deactivation relative to healthy controls in the pre- and postcentral gyri of the ipsilateral hemisphere in the region functionally specialised for hand movement control. We hypothesise that this impairment of deactivation is related to deficits of transcallosal connectivity and GABAergic neurotransmission occurring with the progression of pathology in the MS patients. This study has substantially extended previous observations with a well-powered, multicentre study. The clinical significance of these deactivation changes is still uncertain, but the functional anatomy of the affected region suggests that they could contribute to impairments of motor control.

Background: Recent pathologic investigations have shown that neocortical lesions are frequent in multiple sclerosis (MS). Structural MRI has shown that neocortical atrophy occurs early and can be substantial, but the specific substrate for this atrophy has not been defined quantitatively. Objective: To investigate cortical thickness as well as neuronal, glial, and synaptic densities in MS. Methods: We studied brain samples from 22 patients with MS and 17 control subjects. Neocortical lesions and cortical thickness were assessed on sections stained for myelin basic protein. Neuronal, glial, and synaptic densities were measured in type I leukocortical lesions, nonlesional neocortex, and non-MS control cortex. Immunoautoradiography was used to quantify synaptic densities. Results: Neocortical lesions were common in patients with MS. Subpial type III (44%) and leukocortical type I (38%) lesions were more abundant than intracortical type II (18%) lesions. An overall relative neocortical thinning of 10% ( p = 0.016) was estimated for the patients. Within the type I lesions, we found evidence for substantial cell (glial, 36%, p = 0.001; neuronal, 10%, p = 0.032) and synaptic (47% decrease in synaptophysin, p = 0.001) loss. Nonlesional neocortex did not show significant relative changes in neuronal, glial, or synaptic density. Conclusions: Neocortical neuronal and glial degeneration is significant in multiple sclerosis. Synaptic loss was particularly striking in the neocortical lesions, which should make a major independent contribution to the expression of pathology. New therapies should be directed toward limiting this damage.

Laquinimod (LAQ) is a new oral immunomodulatory compound that reduces relapse rate, brain atrophy and disability progression in multiple sclerosis (MS). LAQ has well-documented effects on inflammation in the periphery, but little is known about its direct activity within the central nervous system (CNS). To elucidate the impact of LAQ on CNS-intrinsic inflammation, we investigated the effects of LAQ on cuprizone-induced demyelination in mice in vivo and on primary CNS cells in vitro. Demyelination, inflammation, axonal damage and glial pathology were evaluated in LAQ-treated wild type and Rag-1-deficient mice after cuprizone challenge. Using primary cells we tested for effects of LAQ on oligodendroglial survival as well as on cytokine secretion and NF-κB activation in astrocytes and microglia. LAQ prevented cuprizone-induced demyelination, microglial activation, axonal transections, reactive gliosis and oligodendroglial apoptoses in wild type and Rag-1-deficient mice. LAQ significantly decreased pro-inflammatory factors in stimulated astrocytes, but not in microglia. Oligodendroglial survival was not affected by LAQ in vitro. Astrocytic, but not microglial, NF-κB activation was markedly reduced by LAQ as evidenced by NF-κB reporter assay. LAQ also significantly decreased astrocytic NF-κB activation in cuprizone-treated mice. Our data indicate that LAQ prevents cuprizone-induced demyelination by attenuating astrocytic NF-κB activation. These effects are CNS-intrinsic and not mediated by peripheral immune cells. Therefore, LAQ downregulation of the astrocytic pro-inflammatory response may be an important mechanism underlying its protective effects on myelin, oligodendrocytes and axons. Modulation of astrocyte activation may be an attractive therapeutic target to prevent tissue damage in MS. Electronic supplementary material The online version of this article (doi:10.1007/s00401-012-1009-1) contains supplementary material, which is available to authorized users.

Dear Sirs, We report the rare case of a primary angiitis of the CNS (PACNS) with isolated spinal cord manifestation. This 44-year-old female presented diffuse dysesthesia with moderate progressive weakness of the lower limbs. There were no cerebral symptoms; cMRI was normal. The diagnosis of PACNS was made by a spinal cord biopsy demonstrating granulomatous vasculitis. The patient was successfully treated with steroids and methotrexate. During a 2 year follow-up our patient did not show any brain or other organ involvement. The 44-year-old female presented with moderate progressive weakness of both legs and burning sensory symptoms of all limbs and the trunk. In addition to moderate paraparesis, the physical examination revealed a moderate pallhypesthesia of the legs with reduced vibratory sense and a diffuse hyp- and dysesthesia below the level of CD5. The family history was unremarkable for neurological diseases. The MRI of the cervical spine showed a gadolinium-enhancing lesion in the posterior part of the myelon with intramedullary edema. This lesion extended from cervical vertebral bodies 2–7 (Fig. 1a). Fig. 1 a MR study of the untreated patient. Sagittal FSE T1-weighted image shows a big, homogeneously enhancing lesion located in the cervical cord. b Follow-up MR study 24 months later. Sagittal FSE T1-weighted image shows no evidence of contrast enhancement ... The cerebral MRI and visual evoked potentials were entirely normal, the examination of the CSF revealed a slight pleocytosis (12 cells/mm3), cytological examination showed regular cells. Oligoclonal bands were absent which makes multiple sclerosis highly improbable. Laboratory examinations did not reveal any evidence for either metabolic (vitamin-B12, folate), autoimmune or infectious disorder. We found no aquaporin-4-antibodies. With normal VEP, we had no evidence for neuromyelitis optica. We started with intravenous high dose methylprednisolone therapy (1 g for 5 days), but symptoms relapsed after 3 months of disease freedom. Before introduction of another immunosuppressive therapy, and to exclude a spinal lymphoma, a biopsy of the spinal lesion was taken. The neuropathological examination revealed a granulomatous vasculitis with transmural inflammation consisting of lymphocytes, epitheloid cells and giant cells (Fig. 2a–h). There was no evidence for systemic organ involvement assessed by thoracic and abdominal computer tomography. Fig. 2 The histological features of primary spinal vasculitis. The neuropathological examination revealed vascular thrombosis (a 100× magnification, H&E staining) and vessel walls with transmural infiltration mainly consisting of several lymphocytes ... Treatment was started with methotrexate (20 mg/week) combined with prednisolone (tapered from 80 to 10 mg/d within 6 weeks). Neurological examination at 3 month intervals revealed normal findings except a slight dysesthesia in the legs. A follow-up MRI after 24 months of treatment demonstrated an obvious regression of the signal intensities within the cervical cord (Fig. 1b), whereas the cMRI remained normal. Spinal symptoms are a rare presentation of primary CNS vasculitis [1]. The previously reported cases with spinal cord involvement also showed progressive paraparesis and dysesthesia as the most common clinical symptoms [2]. However, usually these symptoms occur in the course of the disease and not at disease onset as in our case. A review of the literature showed only eight cases with initially pure spinal cord involvement [3]; half of these cases developed brain lesions later on [1, 4]. The stereotactic biopsy remains the gold standard to assure the diagnosis of a CNS vasculitis [5], but the diagnosis in daily clinical routine is often only based on clinical and imaging findings as well as the response to treatment. This might be a potential reason for overdiagnosing PACNS in clinical routine. As illustrated by our case, histological verification is crucial for the diagnosis. The standard therapy for PACNS consists of corticosteroids (1 mg/kg prednisolone) and pulsed cyclophosphamide (0.5 mg/kg). The treatment with cyclophosphamide can have severe side effects [6]. Monotherapy with steroids leads to higher recurrence rates [7]. Since methotrexate has been successfully used in systemic vasculitis [8], we started treatment with a combination of steroids and methotrexate. Our patient reached remission within 3 months and remains stable now more than 2 years later. In biopsy-proven PACNS of the spinal cord, methotrexate seems to be an effective and less toxic alternative to cyclophosphamide.

The olfactory bulb is an important information coding system in the informational pathway of the olfactory sense, but we still lack a good understanding of the coding mechanism in the bulb and how the odor information from the bulb is translated to the higher cerebral areas. In the past years new knowledge was achieved on the field of the olfactory sensorial transmission from the olfactory receptors to the olfactory bulb: The mammalian nasal epithelium is separated in four regions and each receptor cell type exists just in one of the four areas [1]. Furthermore, olfactory receptors identify odorants based on the chemical features of the odor molecule [2] and receptor neurons of the same type converge to the same spot in the bulb, called glomerulus [3]. This knowledge leads to the assumption that the olfactory bulb might be also separated into four regions and that information coding in the bulb is organized by a chemotopic representation. By using the 2-DG-uptaketechnique, odorant-specific activity patterns across the glomeruli in rat olfactory bulbs can be illustrated [4]. We used the non-negative matrix factorization (NMF) on 143 distinct uptake-images of the rat olfactory bulb in order to get insight in the chemotopic coding map. NMF is designed for revealing inherent structures and similarities in the data and creates a decomposition in parts which display common features of the data. Our analysis on the NMF parts result in four very stable regions of the bulb, which are hierarchically splitted in smaller regions when the number of parts increase. We found a good representation of our data with nine bulb regions, called modules. These modules show some analogy to previously reported regional structures in the bulb [5][6]. Furthermore, we demonstrate a linkage between typical odorant characteristics and our modules, so this speaks in favour of a chemotopic coding map in the bulb. We suggest to understand the modules as a coding character in a coding alphabet. After determining the codeword for each odorant, we designed an odor experiment to investigate whether our coding model can explain the human odor perception. We think our coding model can give new ideas and directions for further research on this topic and want to present our research with a poster.

One object of olfactory research is to understand the coding map of an olfactory bulb. Even after decades of olfactory research, it is still not possible to predict if two odorants smell similar or not without asking human subjects and/or using prior knowledge on exactly these substances. There is only a single source of data, which includes the activity of the whole bulb under exposure of a single compound: The uptake data from Leon & Johnson [1]. Given that the activity is a chemotopic ordered multifactorial code, there are several possible ways these codes might be implemented by nature. So far, specific bulb regions were declared as modules by using the Nonnegative Matrix Factorization. To examine the codes we imagine the modules as letters of an alphabet. Analog to the orthography and grammar of a language, we want to find rules that explain the meaning of the composition of individual words. We consider an alphabet consisting of nine letters, one for each module. Odorants are characterized by module activities and thus form words of the alphabet. The number of activated modules classifies the odorants into groups with different word lengths. To understand complex words, an intuitive approach is to first concentrate on the relations between the letters to each other. We present three different models that describe how odor quality on this modular abstraction could be measured. First of all there is a chemotopic approach, which assumes that odorants with similar chemical epitopes address the same types of receptors. But the corresponding glomeruli are not necessarily close to each other. In order to implement this model we define regions of interest using above-threshold uptake induced by incoming receptor neuron activity. The second model combines the chemotopic approach with the spatial arrangement of the