In order to assess cognitive function in multiple sclerosis (MS) and the effect of cholinergic modulation, experiments were conducted using functional magnetic resonance imaging (fMRI) to assess the brain activation during cognitive tasks. A study comparing the processing of verbal working memory with an N-back task found that patients showed smaller increase in activation than healthy controls with greater task difficulty, suggesting a reduced functional reserve. Controls and patients showed differences of correlations between brain regions activated. Interactions between prefrontal regions may provide an adaptive mechanism that could limit clinical expression of the disease distinct from recruitment of novel processing regions. The effect of Rivastigmine on the cognitive processing in MS patients was tested in a longitudinal study, involving serial fMRI scans. Changes in the brain activation patterns were demonstrated with drug administration, without any changes in behavioural measures. Rivastigmine may act to increase the functioning of the normal neural network reducing the need for previously recruited compensatory mechanisms in MS patients. A study on healthy subjects examined the effect of cholinergic inhibition on cognitive processing and brain activation. Changes in functional activation due to Hyoscine during verbal working memory were found analogous to that in MS patients without any changes in behavioural measures. Processes that potentially impair brain cognitive function may recruit similar compensatory functional adaptive mechanisms. Studies on rats and MS patients explored the effect of Rivastigmine on the relationship of the BOLD fMRI signal with the underlying neural activity. Rivastigmine may be influencing the cortical excitability after direct cortical stimulation but showed only a small effect on the BOLD signal under more physiological neural activity. The neural activity in response to visual stimulation is slightly increased with Rivastigmine in MS patients, a change not detected with functional imaging. These studies suggest that changes in BOLD signal do represent sufficiently large changes of underlying neural activity in the presence of Rivastigmine. The relationship of damage in MS to measures of connectivity was studied using diffusion tensor imaging (DTI). Correlation was found between measures of connectivity and callosal size, a measure of fibre loss. The distribution of lesions was spatially correlated with changes in connectivity due to MS. Thus DTI could be utilized to explore the connectivity changes associated with MS, and the relationship with changes in functional activation.

In den letzten Jahren ist zunehmend deutlich geworden, dass die Multiple Sklerose (MS) nicht nur eine Erkrankung der weißen Substanz des zentralen Nervensystems ist, sondern auch häufig und beträchtlich die graue Substanz in allen klinischen Verlaufsformen betrifft. Besonders die kortikale Pathologie mit entmarkten Läsionen wurde durch verbesserte immunhistochemische Färbetechniken und neuen magnetresonanztomographischen Verfahren ausführlicher untersucht. MS-Patienten leiden klinisch oft an körperlichen Beeinträchtigungen und neuropsychologischen Defiziten, welche die Lebensqualität beeinflussen. Diese Symptome wurden mit Läsionen in der grauen Substanz assoziiert. Mechanismen, die zu dieser Pathologie führen, müssen daher aufgeklärt werden um vorbeugende oder akute Behandlungen entwickeln zu können. Zur pathologischen Untersuchung der grauen Substanz werden angemessene Tiermodelle benötigt, welche die humane kortikale Pathologie wiederspiegeln. Das am häufigsten verwendete Tiermodell in MS-Studien ist die Experimentelle Autoimmune Enzephalomyelitis (EAE), die in ihrem ‘konventionellen’ Immunisierungsprotokoll nur selten den zerebralen Kortex betrifft. Ein EAE-Modell mit Einbezug des Kortex, das MS-Läsionen nachahmt, wurde in Ratten beschrieben. Hierzu wurden proinflammatorische Zytokine in eine vorbestimmte kortikale Region injiziert. Da spezifisch genveränderte Rattenstämme fehlen um die Mechanismen der Pathologie in der grauen Substanz zu untersuchen ist es notwendig das Tiermodell in Mäusen zu entwickelen. Das Ziel dieses Projekts war die Entwicklung eines kortikalen EAE-Mausmodells sowie dessen histopathologische Charakterisierung. Desweiteren wurde kortikales Gehirnmaterial von MS-Patienten im späten Krankheitsstadium auf dendritische Patholgie untersucht. Die kortikale EAE wurde in Myelin Oligodendrozyten Glykoprotein (MOG)-immunisierten BiozziABH (hohe Antikörper) und F1 Nachkommen, die aus BiozziABH und Mäusen mit einem C57BL6/J-Hintergrund generiert worden sind, durch die intrakortikale Injektion von TNF-α und IFN-γ induziert. Histologische Untersuchungen zeigten eine ausgedehnte subpiale Entmarkung und Entzündung im Kortex drei Tage nach der Zytokininjektion in der betroffenen Hirnhälfte. Die Entzündung ging innerhalb von drei Wochen fast vollständig zurück und entmarkte Regionen wiesen teilweise eine Remyelinisierung auf. Axone blieben in läsionalen Regionen erhalten und neuronaler Verlust wurde im Kortex nicht beobachtet. Desweiteren wurde eine Methode etabliert, die es erlaubt detailliert dendritische Pathologien in der Maus zu untersuchen. Kortex-enthaltenes Autopsiematerial von progressiven MS-Patienten mit langandauerndem Krankheitsverlauf zeigte einen Verlust von dendritischen Dornfortsätzen (Spines) in Neurone, die in den unteren korikalen Layern sowohl in chronisch entmarkten Läsionen als auch im umliegenden normal erscheinendem Gewebe der grauen Substanz lokalisiert waren. Im vorliegenden Projekt wurde ein kortikales EAE-Mausmodell entwickelt, das die humane MS-Pathologie der grauen Substanz in frühen Krankheitsstadien wiederspiegelt. Dieses Modell ist für Untersuchungen früher Mechanismen im entmarkten Kortex und für die Erprobung therapeutischer Behandlungen wie die Erhöhung der Remyelinisierung nützlich. Darüberhinaus wurde ein ausgedehnter Verlust dendritischer Dornfortsätze im zerebralen Kortex in chronischen MS-Patienten gezeigt, der auf oft beobachtete neuropsychologische Defizite zurückgeführt werden könnte.

Background: To explore normal-appearing white matter (NAWM) in pediatric-onset multiple sclerosis (MS) patients, using diffusion tensor imaging (DTI). DTI study provides measures of WM integrity in adult MS patients. Pediatric MS patients provide a uniquely early window for exploring pathological components of myelin disruption. Methods: DTI data were obtained for 23 pediatric MS patients and 17 healthy children. Images were acquired using GE LX1.5T scanner (DTI parameters: 25 directions, 5mm slice thickness, b=1000s/mm2). Fractional anisotropy (FA) and apparent diffusion co-efficient (ADC) were analyzed in lesions and NAWM throughout corpus callosum (CC) and hemispheres. Results: Altered NAWM integrity in MS patients relative to controls is demonstrated by: reduced FA values (p<0.0001) and elevated ADC values (p<0.05) throughout CC and hemispheres. Conclusions: DTI measures show widespread disruption of WM integrity in children with MS extending beyond visible lesions. These findings implicate diffuse and potentially very early WM degeneration in MS pathobiology.

Background: To explore normal-appearing white matter (NAWM) in pediatric-onset multiple sclerosis (MS) patients, using diffusion tensor imaging (DTI). DTI study provides measures of WM integrity in adult MS patients. Pediatric MS patients provide a uniquely early window for exploring pathological components of myelin disruption. Methods: DTI data were obtained for 23 pediatric MS patients and 17 healthy children. Images were acquired using GE LX1.5T scanner (DTI parameters: 25 directions, 5mm slice thickness, b=1000s/mm2). Fractional anisotropy (FA) and apparent diffusion co-efficient (ADC) were analyzed in lesions and NAWM throughout corpus callosum (CC) and hemispheres. Results: Altered NAWM integrity in MS patients relative to controls is demonstrated by: reduced FA values (p<0.0001) and elevated ADC values (p<0.05) throughout CC and hemispheres. Conclusions: DTI measures show widespread disruption of WM integrity in children with MS extending beyond visible lesions. These findings implicate diffuse and potentially very early WM degeneration in MS pathobiology.

Neuropathic pain (NPP) is a chronic syndrome suffered by patients with multiple sclerosis (MS), for which there is no cure. Underlying cellular mechanisms involved in its pathogenesis are multifaceted, resulting in significant challenges in its management. In addition to its complex pathophysiology, the clinical management of MS-induced NPP is further complicated by the lack of clinical therapeutics trials specific to this population. The primary aim of the work underlying this thesis was to contribute to the evidence-based management of individuals with MS-induced NPP through the completion of two clinical therapeutics trials in this population. A secondary aim was to describe pain variability in this patient population through the development and validation of a pain variability algorithm tool. Resulting from this work, we demonstrated that nabilone – a synthetic oral cannabinoid – represents an effective, well-tolerated and novel treatment for MS-induced NPP. Additionally, we show that the SSRI paroxetine was poorly tolerated in our patient population, with a correspondingly high attrition rate. As a result, we were unable to determine any treatment effect in this trial due to insufficient recruitment due to drop-out. Lastly, we were able to define and describe pain instability in this cohort, noting that approximately 30% of individuals with MS-induced NPP experiencing highly variable daily pain. The results of these projects provide novel information for this patient population. Patients currently living with the daily burden of MS-induced NPP would benefit from additional trials ensuing from this, and other, research in order to initiate a momentum for much-needed clinical research in this complicated patient cohort.

Endoplasmic reticulum (ER) stress is a homeostatic mechanism, which is utilized by cells to adapt to inter- and intra-cellular changes. There is a burgeoning literature showing that the human endogenous retroviral envelope glycoprotein, Syncyin-1, oxidative stress and reactive oxygen species participate in the pathogenesis of multiple sclerosis (MS). I investigated the contribution of Syncytin-1-induced ER stress in MS and its animal model, experiment autoimmune encephalomyelitis (EAE). The prototypic ER stress biomarker, XBP-1 spliced variant (XBP-1/S), was increased in cerebral white matter of MS patients compared to non-MS controls and was correlated with Syncytin-1 expression. Syncytin-1 over-expression caused glia cytotoxicity but was mitigated by the ROS scavenger, crocin. Treatment with crocin on day 7 post-EAE induction ameliorated EAE disease severity in mice by reducing EAE pathology. Herein, I demonstrate that crocin attenuates Syncytin-1-induced ER stress in astrocytes while also diminishing disease severity in EAE in conjunction with suppression of neuroinflammation.

Multiple sclerosis (MS) is an idiopathic neurodegenerative, demyelinating disease of the central nervous system (CNS). MS affects females more than males (3:1) and pregnancy reduces the number of relapses especially during the third trimester when 17-beta-estradiol (E2) and estriol (E3) are at their highest levels. In order to study the role of estrogens as potential therapeutic agents for MS we investigated their role in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelination (TVID). SJL female mice were infected intracranially with Theiler's virus or PBS. The mice in the treatment groups were clinically scored and at week 20 they were ovarectomized (OVx) and given a subdermal pellet containing either 1) 0.1mg of E2, 2) 5mg of E3, or 3) placebo. Four weeks after treatment initiation, the mice were sacrificed and tissue samples were collected and vertebral columns and brains were fixed and placed in paraffin for histological analysis using either hematoxylin and eosin (H&E) stain for general anatomic features or Weil's stain for myelin. No signs of clinical disease developed in any of the sham-infected mice. Prior to ovariectomy, infected mice had developed significant clinical scores indicative of demyelination. Mice in the placebo and E3-treatment groups deteriorated rapidly whereas the E2-treated mice improved significantly during the course of the treatment. Uteri were used to assess hormonal effects post-ovariectomy. Hormone treated groups were significantly different from placebo, indicating hormones were present. Hormone treatment showed significant differences among treatment groups for both inflammation and demyelination. E2-treatment significantly decreased inflammation compared to placebo and E3. E2 was also effective in reducing demyelination compared to placebo groups but not E3. E3 treatment was effective in reducing inflammation compared to placebo, but no significance was found for demyelination. Both E3 and E2 treated mice developed lower antibody levels against TMEV. The improvement in clinical signs, inflammation, demyelination, and the reduction of antibody levels in 17-beta-estradiol-treated mice indicate a therapeutic potential for the treatment of MS.

1) Introducció: L’esclerosi múltiple (EM) és una malaltia crònica de probable origen autoimmune, d’inici a l’edat adulta jove, que afecta fonamentalment a la substància blanca del sistema nerviós central. Es manifesta amb dèficits neurològics autolimitats (brots) que posteriorment van donant lloc a una discapacitat física progressiva; aproximadament un 50% dels pacients desenvoluparan un deteriorament cognitiu de tipus subcortical associat. L’apolipoproteïna E (ApoE) s’ha involucrat a la regeneració dels axons i la reparació de la mielina mitjançant la seva contribució al transport lipídic i el seu alel e4 s’ha relacionat amb un augment de risc de desenvolupar una malaltia d’Alzheimer. A l’EM l’alel e4 s’ha estudiat com a possible marcador de susceptibilitat, de progressió clínicoradiològica o de deteriorament cognitiu, mentre que l’alel e2 sembla que podria conferir un cert efecte protector. Objectius: Els objectius d’aquest treball de recerca són: 1) Comprovar l’eficàcia de l’interferó beta-1b a retrassar la progressió de la discapacitat dels pacients amb EM remitent-recurrent i determinar els factors clínics pronòstics de la malaltia 2) Determinar si el grau de deteriorament cognitiu dels pacients amb EM es relaciona amb les variables clíniques de la malaltia i/o amb l’alel e4 de l’ApoE. 3) Confirmar si els alels e4/e2 de l’ApoE es relacionen amb la resposta al tractament amb interferó beta-1b dels pacients amb EM Mètodes: Es realitza un estudi longitudinal i prospectiu, que inclou tots els pacients (n=115) de la Unitat d’Esclerosi Múltiple de Bellvitge (L’Hospitalet, Barcelona) amb el diagnòstic d’EM remitentrecurrent que iniciaren tractament amb interferó beta-1b, segons els criteris del Consell Assessor de l’ICS, durant una mitja de seguiment de cinc anys. Es registraren les variables clínicodemogràfiques basals i durant el tractament i es determinaren els marcadors de resposta terapèutica. Per tal de valorar l’efecte de l’interferó beta-1b sobre la progressió de la discapacitat es va comparar la cohort tractada amb una cohort històrica del mateix centre, que complia els mateixos criteris d’inclusió. Es va realitzar un estudi neuropsicològic complert de 50 pacients de la cohort principal (que es va comparar amb una cohort de 35 individus sans) i es varen obtenir mostres de sang per la determinació dels alels e4/e2 de l’ApoE segons els mètodes estàndards. Resultats: 1) El temps per progressar un punt a l’escala de discapacitat (EDSS) a la cohort tractada amb interferó beta-1b fou superior al temps de la cohort històrica (72.94 versus 36.94 mesos, p=0.002). L’activitat inflamatòria inicial de la malaltia (brots en els primers dos anys i temps entre el primer/segon brot) es va relacionar amb la progressió precoç de la discapacitat i la conversió a fase secundària progressiva. 2) Tot i que es varen trobar diferències significatives entre el grau de deteriorament cognitiu dels pacients i els individus sans, no es va trobar relació amb els marcadors de progressió clínica de la malaltia ni de resposta al tractament inmunomodulador El grau de deteriorament cognitiu no es relacionar amb la presència de l’alel e4 a la nostra sèrie. 4) L’alel e4 de l’APOE no es va relacionar amb cap de les variables de resposta al tractament inmunomodulador, mentre que l’alel e2 fou la única variable independent (p=0.036) predictora de progressió a una discapacitat moderada (EDSS=3). Conclusions: 1) L’interferó beta-1b és eficaç a retrassar la progressió a la discapacitat a la nostra cohort de pacients amb EM durant una mitja de seguiment de quasi cinc anys. 2) L’activitat inflamatòria inicial de la malaltia és predictora de la progressió precoç durant el tractament amb interferó beta-1b. 3) L’alel e4 de l’ApoE no es relaciona amb la resposta al tractament inmunomodulador ni amb el grau de deteriorament cognitiu a la nostra sèrie. 4) L’alel e2 de l’ApoE sembla conferir un efecte protector respecte la progressió a la discapacitat moderada dels pacients amb EM tractats amb interferó beta-1b. / Introduction: There is limited long-term data on the effect of interferon beta-1b (IFN-β-1b) on disability progression in patients with multiple sclerosis (MS). The role of the apolipoprotein E (ApoE) polymorphism has been well demonstrated in neurodegenerative diseases such as Alzheimer; however, its role in MS remains unclear. Aims: This prospective longitudinal study investigated: 1) Early clinical prognostic markers of disease activity and progression in 115 patients with relapsing-remitting MS treated with IFN-β-1b; progression of disability in IFN-β-1b-treated group was compared with an historic non treated cohort of MS patients (n=44). 2) The role of ApoE-4 as surrogate marker of cognitive decline in MS. 3) The usefulness of ApoE alleles in predicting the response to IFN-β-1b. Results: 1) The IFN-β-1b-treated group experienced a slower progression of disability than the untreated cohort (72.94 versus 36.94 months, p=0.002), suggesting that IFN-β-1b treatment delays progression of disability in relapsing-remitting MS. 2) The time between the first and second relapse and the number of relapses in the first two years of MS were related to early progression (p= 0.026) and to early conversion to secondary progressive MS (p=0.028). 3) No association between e4 allele and cognitive impairment was found; moreover, cognitive decline was not related to disability progression or other clinical markers in our cohort. 4) The e4 allele had no prognostic value for the response to IFN-β-1b in our cohort, whereas the e2 allele was significantly associated with increased time to moderate disability (p=0.036), suggesting a protective effect of this allele. Conclusions: 1) IFN-β-1b treatment delays progression of disability in our cohort MS patients 2) ApoE-4 allele was not related to cognitive decline or response to IFN-β-1b treatment 3) The e2 allele delayed the progression of disability in our MS cohort

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 31, 2007). Includes bibliographical references.

Thesis (Ph. D.)--University of Toronto, 2005.