Multiple Sclerosis From neuroscience to treatment Dr Rosie

Multiple Sclerosis From neuroscience to treatment Dr Rosie Jones The Brain Centre, Southmead Hospital Spring 2015 1

Characteristics of MS “Autoimmune mediated inflammation (causing damage) triggered by unknown factors in susceptible individuals and resulting in”: • • • Patchy damage to myelin / loss of Oligodendrocytes (? ) Failure of nerve conduction Axonal damage Axonal/nerve cell degeneration Reduced brain Volume Development of scarring In the CNS Spring 2015 MS Research Unit

This session • Understanding MS – Demographics – Pathology • • Immuno-pathology Myelin damage Axonal damage Routes to designing treatment – Possible CNS repair mechanisms – Some examples of MS Symptoms Spring 2015 3

MS Demographics • Prevalence between 10/100, 000 and 170/100, 000 (around 100, 000 in the UK , 3 million world wide) • Most common in temperate latitudes • 2: 1 women: men • Diagnosed in early adulthood (teens to 30 s, range “x” to 70 years) Childhood MS now acknowledged. • Familial (genetic) susceptibility + unidentified factors • Significantly more common in Caucasian populations • Multiple symptoms-sensory and motor • Progressive with or without relapses Relapse Remitting, Primary Progressive Secondary Progressive (RR PP SP) Spring 2015 4

POPULATION STUDIES Some examples of prevalence figures world-wide: UK 99 -178/100, 000 (Orkney 287/100, 00? ) France 50/100, 000 Italy 35 -50/100, 000 USA 70 -165/100, 000 (New Mexico 22/100/000) Australia 11 -40/100, 000 New Zealand 24 -77/100, 000 Middle East 20 -50/100, 000 (? ) Spring 2015 5

Environment: MIGRATION STUDIES Studies of migration from high prevalence area to low prevalence area: • South Africa and Israel are both low prevalence areas. • Europeans migrating to these areas retain high prevalence risk unless they migrate before the age of 15 years. Spring 2015 6

Environment: EXPOSURE • Levels of sunlight/Vit. D – Temperate latitudes, lack of exposure to sun • Exposure to chemicals – Solvents, fuel pollution, smoking • Exposure to (viral) infections – Measles, hepatitis, herpes etc. Vaccinations • Exposure to stress/trauma – MS may occur/worsen after giving birth, physical injury traumatic life events • Dietary differences • High saturated fat levels-lack of polyunsaturated fats in diet. Spring 2015 7

MULTIPLE SCLEROSIS Spring 2012 Spring 2015 MS Research Unit 8

EDSS expanded disability status scale Spring 2015 9 Kurtzke JF (1983) Neurology 33 (11): 1444– 52.

Progression of Disability Occurrence, Extent of Severity MS Courses as Redefined by MRI SPMS Clinical Impairment MRI-Defined Plaque Burden Late RRMS Enhancements Early RRMS Time Spring 2015 Adapted with permission from Dr. J. S. Wolinsky. 10

Natural History of MS • Relapse remitting phase- intermittent clinical events 1 to 4/year - 5 to 20 years • Secondary progressive phase-few or no relapses, steady progression in disability levelling off by about 20 years after diagnosis • Primary progressive – steady increase in disability with or without relapses. • Severe - very rare. Fast progression to wheelchair/bed-bound/death in 3 to 10 years Spring 2015 11

Pathology Development of an MS Plaque Inflammation, Demyelination Axonal damage Spring 2015 1

Characteristics of MS pathology “Autoimmune mediated inflammation resulting in”: • Damage to/loss of myelin/or loss of Oligodendrocytes? • Axonal damage • Axonal degeneration • Loss of brain bulk Spring 2015 13

Myelin and Nerve Conduction Spring 2015 14

Demyelination: Myelin and Oligodendrocytes in the CNS • Myelination in the CNS is by Oligodendrocytes-(peripheral nervous system myelin is produced by Schwann cells-not present in CNS and not affected by MS) • Each Oligodendrocyte produces myelin extensions that wrap around several nerve axons • What happens to Oligodendrocytes in MS? Spring 2015 15

OLIGODENDROCYTES Oligodendrocyte in culture (Immunofluorescence for galactocerebroside) Spring 2015 16

Brain Imaging Spring 2015 17

PATHOLOGY Not all aspects of MS pathology are understood • Blood brain barrier disruption - immune cells move into CNS. • Complex inflammatory responses • Localised CNS damagedemyelination, axonal damage Spring 2015 18

Pathology Local infiltration of inflammatory cells across blood vessel walls requires: • Adhesion to blood vessel epithelium • Transit across blood vessel wall • Migration into local brain tissue Spring 2015 19

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Evidence that MS is an Autoimmune disease. Immune activity overview • Activated T lymphocytes appear in the blood and CSF. Reactive to myelin proteins e. g. *MOG or MBP • Activated T cells and macrophages seen in MS plaques • Increased CD 4+ (helper) to CD 8+ (suppresser) T cell ratio. • Local Ig. G production seen in CSF-action of B cells? Possible antibody candidates: *MOG (oligodendrocyte glycoprotein), MBP (myelin basic protein), viral infection? Spring 2015 21

William Lindsey and Jerry Wolinsky • Spring 2015 22

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Immune markers Increased circulating levels of immune markers of immune activity during MS exacerbations observed including: • • • T cell activation markers Markers of macrophage activation Markers of cellular adhesion Markers of extracellular matrix breakdown Markers of inflammatory cellular amplification Spring 2015 24

T cell activation markers Markers of T Helper cell (Th-1) activation • Activated T helper cells release IL-2 (soluble IL-2 receptors detected) • IL-4 is associated with T cell activation • Interferon-gamma (INF ) is associated with T cell activation • Macrophage activation follows. TNF IL=interleukin, TNF = tumour necrosis factor, INF=interferon Spring 2015 25

Macrophage activation Macrophage demyelination in vitro is mediated by tumour necrosis factor-(TNF ) and Interferon (INF ) • TNF is increased in MS during relapse • INF and TNF act synergistically to heighten immune responses • TNF damages Oligodendrocytes in vitro Beta interferon, INF , counteracts the influence of TNF and INF Spring 2015 26

Aims of Disease Modifying Drugs DMDs are designed to break a key link or links in the presumed pathway to tissue destruction in active disease Links include • Immune cell activation (PB, CNS other? ) • Immune cell adhesion and migration (BBB) • Immune cell clonal expansion (PB or CNS) • Immune cell/cytokine cycle amplification Spring 2015 27

William Lindsey and Jerry Wolinsky • Spring 2015 28

Autoreactive T Cells Danger Signal or Trigger T T T Activation, Differentiation, Clonal Expansion T T Adhesion/Attraction T Periphery Transmigration T BBB B Antibodies T APC Local Reactivation APC M NO TNF- IFN- Release of Cytokines; Recruitment of M T CNS TNF- Demyelination and Axon Loss Spring 2015 Adapted with kind permission from Prof. R. Hohlfeld. 1

The Dual Nature of Inflammation in MS Pro-inflammatory and Neurotoxic Factors · · · · Th 1 cytokines TNF- IL-1 Nitric oxide Reactive oxygen species Glutamate Antibodies and complement Cell-mediated neurotoxicity TISSUE DAMAGE Spring 2015 Anti-inflammatory and Neuroprotective Factors · · Th 2 cytokines TGF- IL-1 Neurotrophic factors – BDNF – NGF – NT-3 – CNTF – GDNF TISSUE PROTECTION 30

Aims of Disease Modifying Drugs DMDs are designed to break a key link or links in the presumed pathway to tissue destruction in active disease Links include • Immune cell activation (PB, CNS other? ) • Immune cell adhesion and migration (BBB) • Immune cell clonal expansion (PB or CNS) • Immune cell/cytokine cycle amplification Spring 2015 31

Clonal cell expansion-promotion of cellular reactivity? Mechanisms for clonal expansion of autoreactive immune cells and cellular amplification/restriction unclear • Following BBB breach other cells follow: In MS plaques T cells and macrophages • Macrophage activation: e. g. TNF , macrophage inflammatory proteins • Pro-inflammatory cytokines detected in lesions – TNF , INf- , IL-2, IL-6, Il 12. Spring 2015 32

Treatments based on modifying immune function • Some tested disease modifying agents – Beta interferon- (betaseron betaferon, Avonex) – Glatiramir acetate (Copaxone, copolymer 1) – Natalizumab (Antegren)-affects adhesion molecules – Campath H (Alemtuzumab) acts against CD 52 lymphocytes – Cell proliferation modulation? – Stem cells? ? Spring 2015 33

BBB Action of Adhesion Molecules Peripheral circulation Basement membrane Matrix degrading enzymes e. g. matrix metallo-proteinases T cells express adhesion molecules e. g. LFA-1 VLA-4 CNS Blood vessels express Adhesion molecules e. g. E-Selectin LFA- Leukocyte function associated antigen-1 VLA Very late antigen-4 Spring 2015 34

Current drug trials Cladribine Oral x 5 x 2 mo Depletes resting and dividing lymphocytes Lymphocytes and monocytes Alemtuzumab ivx 5 dx 12 mo CD 52+ Lymphocytes Ablation lymphocytes and monocytes Rituximab Ivx 2 rep CD 20+B lymphocytes Depletes naïve and memory B cells Aticept sc Blys. S and APRIL Affects B lymphocyte activation Daclizumab ivxmo CD 25+ Lymphocytes Expansion of CD 2 56 and NK clones – takes out activated l’cytes Fingolimod Oral daily SIP Receptors Sequesters lymphocytes in lymph tissue Laquinomod Oral 3 xd Enhances Th 11 responses Immunomodulatory Teriflunomide Oral daily Blocks pyrmidine synthesis immunomodulatory BG 00012 Oral 3 xd Enhances Th 11 responses imunomodulatory Spring 2015 35

Clinical outcome of some DMDs • Reduction in number of relapses in early RR MS • Reduction in new MRI (enhancing) CNS lesions in early RR MS • Reduction in progression of disease by 9 to 12 months • Changes broadly reverse when treatments stops. Spring 2015 36

Current treatments • Inflammatory phase-steroids • Non–acute phases – General immunosuppressant agents – Possible non-drug immuno-suppressants • e. g. diet, lifestyle changes • Statins? Spring 2015 37

Damage to axons and nerve cells Spring 2015 1

Myelin damage and axonal loss in MS Spring 2015 39

Fate of axons and nerve cells It is now clear that axonal loss and damage are major features of MS • Presence of NAA (N-acetyle aspartate) in MR spectroscopy • Loss of brain bulk • Increasing disability • Alterations in physiological measures Spring 2015 40

Neuronal/axonal damage Axonal damage thought to be secondary to myelin damage. Loss of trophic support or direct injury to axon BUT In some models of MS axonal damage appears early with or without evidence of demyelination. AND Reduction in CNS bulk continues in absence of demyelination episodes (e. g. Progressive MS) Spring 2015 41

Possible causes of axonal loss Damage by • Proteases • Inflammatory cytokines • Nitric oxide • Glutamate/Glutamine Evidence of up-regulation of all these possible mechanisms seen in active MS. Spring 2015 42

Possible mechanisms of repair Spring 2015 1

Remyelination requires: • Viable myelin making cells (oligodendrocytes) • Intact nerve processes • Suitable environment for cellular survival and activation Spring 2015 44

Oligodendrocyte - development Oligodendrocyte (OD) progenitor OD precursor Pre-OD Adult OD progenitor ? Immature OD Mature OD Spring 2015 45

Features of Oligodendrocytes • Progenitor cells +ve for 04 mabs. Present throughout CNS. Undifferentiated. • Precursor cells +ve for Galacto-cerebroside (Gal. C). Earliest OG specific marker to be expressed. Large pale nucleus. • May produce myelin processes. • Mature cell +ve for myelin oligodendrocyte glycoprotein MOG. Small dense nucleus. Spring 2015 46

Possibilities for promoting remyelination • • Stimulate cell activity/differentiation Block progenitor cell inhibitory factors Block agents that kill myelin-making cells Transplant new OG cells-stem cells Spring 2015 47

Oligodendrocytes and myelin Extensive remyelination does not occur despite presence of intact axons and Gal. C+ve cells in the same lesion area. • Gal. C +ve cells do not appear to mature into MOG +ve cells to form new myelin – Cells appear quiescent. Die before they can mature? • Gal. C and MOG +ve cells appear to be destroyed in long term plaques – MOG+ve (mature) cells are destroyed selectively • Possibilities for treatmentstimulate cell activity/differentiation block inhibitory/cytotoxic factors Induce/transplant new OG cells? Spring 2015 48

Nerve cell repair Loss of axonal capability to repair may be : • Intrinsic-no mechanism in mature CNS • Due to Nogo-A mediated damage-Block or ablate. • Lack of access to or response to nerve growth factors • Hostile cytotoxic soup-too many factors to control Neurotrophic support may be developed e. g. CNTF ciliary neurotrophic factor. Spring 2015 49

Stem cells Can stem cells be used to effect repair in MS? • Types of possible stem cells – Resident/introduced oligodendrocyte precursor cells. • Used in early repair? Depleted? – Embryonic stem cells • ethical and cross reactivity issues. Tumours – Other stem cells-e. g. haematopoietic • Autologous and relatively easy to obtain Spring 2015 50

C. What is known about adult stem cell differentiation? Figure 2. Hematopoietic and stromal stem cell differentiation. Click here for larger image. Spring 2015 51

Symptoms in MS Multiple symptoms both motor and sensory • Muscle weakness, fatigue, stiffness (spasticity) contracture • Sensory changes pain, burning/ tightness/numbness. Vision. Joint position. • Loss of motor control-ataxia tremor • Continence problems • Cognitive changes • Other behavioural and mood changes Spring 2015 52

Physical fatigue Neuromuscular fatigue and weakness Illustrated as change in force output with time. Loss of force may be due to central or peripheral (muscle) fatigue. Spring 2015 53

Neuromuscular Fatigue in MS Spring 2015 54

Symptom Treatment • Spasticity. Muscle stiffness and spasms- loss of central inhibition of spinal motoneurones. Baclofen • Loss of bladder control spinal lesions block descending and ascending pathways. Urine retention is most dangerous-can lead to kidney damage. • Pain. Neuropathic pain, very difficult to treat. Pain from muscle contractures. Spring 2015 55

Fatigue Statements • “Fatigue is one of the worst symptoms” “Having to use a wheel chair is a big change but it’s not as bad as the fatigue”. • -”like having a really bad ‘Flu” “You feel weak and unable to get about. It comes on without warning and is one of the hardest things to deal with” Spring 2015 56

Mental Fatigue • • • Runs out of steam Cannot make effort May need to rest or sleep May feel depressed or frustrated Usually worse when hot or under stress Spring 2015 57

Mental Fatigue • • Loss of concentration Ability to think through/solve problems Reduced motivation Over whelming need to rest or sleep Affects up to 90% of people with MS Spring 2015 58

Intention Tremor Definition-An increase in tremor amplitude towards the termination of a visually guided goal-directed movement. • 30% of the MS population are estimated to have upper limb tremor • Causes dependence in daily activities • Subjects with severe tremor have a high level of disability and loss of independence. Spring 2015 59

Figure of 8: Control subject Spring 2015 60

Example of figure of 8 data collection (severe tremor) Spring 2015 61

62 Measurement of Tremor • Second example: reach-retrieve (functional) test