The role of trauma in the pathogenesis of multiple sclerosis: a review

An Overview of the History, Pathophysiology, and Pharmacological Interventions of Multiple Sclerosis

Multiple sclerosis (MS) is an immune-inflammatory disease that attacks and damages myelinated axons in the central nervous system (CNS) and causes nontraumatic neurological impairment in young people. Historically, Lidwina of Schiedam documented the first MS case. After that, Augustus d'Este wrote for years about how his MS symptoms worsened. Age, sex, genetics, environment, smoking, injuries, and infections, including herpes simplex and rabies, are risk factors for MS. According to epidemiology, the average age of onset is between 20 and 40 years. MS is more prevalent in women and is common in Europe and America. As diagnostic methods and criteria change, people with MS may be discovered at earlier and earlier stages of the disease. MS therapy has advanced dramatically due to breakthroughs in our knowledge of the disease's etiology and progression. Therefore, the efficacy and risk of treatment medications increased exponentially. Management goals include reducing lesion activity and avoiding secondary progression. Current treatment approaches focus on managing acute episodes, relieving symptoms, and reducing biological activity. Disease-modifying drugs such as fingolimod, interferon-beta, natalizumab, and dimethyl fumarate are the most widely used treatments for MS. For proof of the efficacy and safety of these medications, investigations in the real world are necessary.

A Diagnosis of Multiple Sclerosis Following Whiplash Injury: Is There a True Association?

We report a case of a previously well, 25-year-old Caucasian female whose diagnosis of multiple sclerosis (MS) followed significant trauma. Her symptoms and signs developed quickly and satisfied the criteria for rapidly evolving relapsing-remitting MS. She was started on natalizumab (Tysabri) and was stabilized. We discuss the existing literature on traumatic demyelination and possible underlying mechanisms.

Concussion in adolescence and the risk of multiple sclerosis: A retrospective cohort study

BACKGROUND

Physical trauma, specifically concussions sustained during adolescence, has been hypothesized to be a risk factor for multiple sclerosis (MS).

OBJECTIVE

To examine the association between adolescent concussions and future MS diagnosis.

METHODS

This retrospective study using linked administrative databases from Ontario, Canada, identified 97,965 adolescents (age 11-18 years) who sustained ⩾1 concussion and presented to an emergency department between 1992 and 2011. Cases were matched 1:3 with individuals who had not sustained a concussion based on age, sex, address, and index date. The primary outcome was MS diagnosis, using a validated MS diagnosis definition: ⩾1 hospitalization or ⩾5 physician billings within 2 years.

RESULTS

A concussion during adolescence was associated with a significantly increased risk of MS (hazard ratio (HR) = 1.29, p = 0.03). Sex-specific analysis revealed that only males who sustained a concussion in adolescence had a raised risk of MS (HR = 1.41, p = 0.04).

CONCLUSION

This study supports an association between concussions in adolescence and future MS diagnoses, highlighting the potentially serious long-term effects of concussions.

Recrudescence of Old Stroke Deficits Among Transient Neurological Attacks

Background

Recrudescence of old stroke deficits (ROSD) is a reported cause of transient neurological symptoms, but it is not well characterized.

Objective

We sought to determine the prevalence, potential triggers, and clinical outcome of ROSD in a cohort of patients presenting with acute transient neurological attack (TNA) and absent acute pathology on brain imaging.

Methods

We retrospectively analyzed 340 consecutive patients who presented with TNA and no acute pathology on brain imaging that were included in an institutional stroke registry between February 2013 and April 2015. The presumed TNA cause was categorized as transient ischemic attack (TIA), ROSD, and other cause. Baseline characteristics, triggers, cardiovascular complications within 90 days, and death were recorded.

Results

The prevalence of ROSD in the studied cohort was 10% (34/340). Infectious stressors and acute metabolite derangements were more common in ROSD compared to TIA (P < .05, each). Compared to TIA and the other TNA, ROSD was more likely to have more than 1 acute stressor (P < .001). Patients with ROSD had similar vascular risk factors compared to TIA (P > .05), including hypertension, diabetes mellitus, peripheral vascular disease, hyperlipidemia, and similarly used HMG-CoA reductase inhibitor, antihypertensive, and antiplatelet medications. Among the patients with an available 90-day follow-up (n = 233), cardiovascular events were more frequent in the TIA group as compared to other TNA (P < .05).

Conclusion

ROSD is common and distinct from TIA and is associated with a triggering physiologic reaction leading to transient reemergence of prior neurologic deficits. Further study of the mechanism of this phenomenon is needed to help better identify these patients.

Spinal cord injury is related to an increased risk of multiple sclerosis: a population-based, propensity score-matched, longitudinal follow-up study

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system (CNS). Trauma to the CNS has been postulated to play a role in triggering CNS autoimmune disease. Although the association between traumatic brain injury and MS has been suggested in previous studies, epidemiological data on the association between spinal cord injury (SCI) and MS is still lacking. The aim of the present population-based, propensity score-matched, longitudinal follow-up study was therefore to investigate whether patients with SCI were at a higher risk of developing MS. A total of 11,913 subjects ages between 20 and 90 years with at least two ambulatory visits with the principal diagnosis of SCI in 2001 were enrolled in the SCI group. We used a logistic regression model that included age, sex, pre-existing comorbidities, and socioeconomic status as covariates to compute the propensity score. The non-SCI group consisted of 59,565 propensity score-matched, randomly sampled subjects without SCI. Stratified Cox proportional hazard regression with patients matched by propensity score was used to estimate the effect of SCI on the risk of developing subsequent MS. During follow-up, five subjects in the SCI group and four in the non-SCI group developed MS. The incidence rates of MS were 17.60 (95% confidence interval [CI], 5.71-41.0) per 100,000 person-years in the SCI group and 2.82 (95% CI, 0.77-7.22) per 100,000 person-years in the non-SCI group. Compared with the non-SCI group, the hazard ratio of MS for the SCI group was 8.33 (95% CI, 1.99-34.87, p=0.0037). Our study therefore shows that patients with SCI have an increased risk of developing MS.

Traumatic Injury and Multiple Sclerosis: A Systematic Review and Meta-Analysis

A systematic review/meta-analysis of literature addressing a possible association between traumatic injury and onset of multiple sclerosis was conducted. Medline, Embase, Cochrane DSR, Ovid HealthStar, CINAHL, ISI Web of Science and Scopus were searched for analytical studies from 1950 to 2011. Two investigators independently reviewed articles for inclusion, assessing their quality using the Newcastle-Ottawa Scale. Of the 13 case-control studies included, 8 were moderate quality and 5 low; of the 3 cohort studies 2 were high and 1 moderate. Meta-analysis including moderate and low quality case-control studies produced a modest but significant odds ratio: 1.41 (95% confidence interval: 1.03, 1.93). However, when low quality studies were excluded, the resulting odds ratio was non-significant. Cohort studies produced a non-significant standardized incidence ratio of 1.00 (95% confidence interval: 0.86, 1.16). These findings support the conclusion that there is no association between traumatic injury and multiple sclerosis onset; more high quality cohort studies would help to confirm this observation.

The epidemiology of multiple sclerosis: insights to disease pathogenesis

The purpose of studying the epidemiology of multiple sclerosis (MS) is twofold. First, it is important to understand clearly the natural history of the illness in order to assist patients in making decisions about their future with respect to issues such as family planning, the importance of securing lifelong healthcare, their ability to get and maintain employment, and making appropriate choices of therapy for their particular circumstances. This is not to suggest that, even with the best possible information, the ultimate prognosis for any individual can be predicted with absolute accuracy. It cannot. Nevertheless, accurate information can be very helpful both to reassure patients that many individuals with MS do remarkably well in the long term (perhaps, especially, with current and future therapies) and also to empower individuals with respect to their ability to make their own life choices. Second, and arguably the more important purpose for studying the epidemiology of MS, is to gain insights to the underlying causes of the disease. Indeed, if the principal mechanisms of disease pathogenesis were to be understood clearly, then it might be possible to entertain notions of either a cure for existing disease or the primary prevention of future disease. Much of our current understanding of disease pathogenesis, as discussed in other chapters of this volume, has been derived from basic science investigations of animal models of MS such as experimental autoimmune encephalomyelitis (EAE), and these models have provided considerable insight both to the complexity of the mammalian immune system and to the mechanisms underlying its dysfunction in inflammatory autoimmune conditions. Nevertheless, MS is a disease of humans without any known, naturally occurring, counterpart in any nonhuman species. For this reason, the clues to disease pathogenesis provided by a study of basic epidemiologic facts regarding MS (and by a systematic consideration of their implications) are essential to a comprehensive understanding of the human illness we call MS.

The paradox of chronic neuroinflammation, systemic immune suppression, autoimmunity after traumatic chronic spinal cord injury

During the transition from acute to chronic stages of recovery after spinal cord injury (SCI), there is an evolving state of immunologic dysfunction that exacerbates the problems associated with the more clinically obvious neurologic deficits. Since injury directly affects cells embedded within the "immune privileged/specialized" milieu of the spinal cord, maladaptive or inefficient responses are likely to occur. Collectively, these responses qualify as part of the continuum of "SCI disease" and are important therapeutic targets to improve neural repair and neurological outcome. Generic immune suppressive therapies have been largely unsuccessful, mostly because inflammation and immunity exert both beneficial (plasticity enhancing) and detrimental (e.g. glia- and neurodegenerative; secondary damage) effects and these functions change over time. Moreover, "compartimentalized" investigations, limited to only intraspinal inflammation and associated cellular or molecular changes in the spinal cord, neglect the reality that the structure and function of the CNS are influenced by systemic immune challenges and that the immune system is 'hardwired' into the nervous system. Here, we consider this interplay during the progression from acute to chronic SCI. Specifically, we survey impaired/non-resolving intraspinal inflammation and the paradox of systemic inflammatory responses in the context of ongoing chronic immune suppression and autoimmunity. The concepts of systemic inflammatory response syndrome (SIRS), compensatory anti-inflammatory response syndrome (CARS) and "neurogenic" spinal cord injury-induced immune depression syndrome (SCI-IDS) are discussed as determinants of impaired "host-defense" and trauma-induced autoimmunity.

Abnormal blood-brain barrier permeability in normal appearing white matter in multiple sclerosis investigated by MRI

Objectives

To investigate whether blood–brain barrier (BBB) permeability is disrupted in normal appearing white matter in MS patients, when compared to healthy controls and whether it is correlated with MS clinical characteristics.

Methods

Dynamic contrast-enhanced MRI was used to measure BBB permeability in 27 patients with MS and compared to 24 matched healthy controls.

Results

Permeability measured as K^trans was significantly higher in periventricular normal appearing white matter (NAWM) and thalamic gray matter in MS patients when compared to healthy controls, with periventricular NAWM showing the most pronounced difference. Recent relapse coincided with significantly higher permeability in periventricular NAWM, thalamic gray matter, and MS lesions. Immunomodulatory treatment and recent relapse were significant predictors of permeability in MS lesions and periventricular NAWM. Our results suggest that after an MS relapse permeability gradually decreases, possibly an effect of immunomodulatory treatment.

Conclusions

Our results emphasize the importance of BBB pathology in MS, which we find to be most prominent in the periventricular NAWM, an area prone to development of MS lesions. Both the facts that recent relapse appears to cause widespread BBB disruption and that immunomodulatory treatment seems to attenuate this effect indicate that BBB permeability is intricately linked to the presence of MS relapse activity. This may reveal further insights into the pathophysiology of MS.

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BBB permeability is higher in MS Normal Appearing White matter compared to controls.

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BBB permeability is correlated with the number of days since clinical MS relapse.

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BBB permeability seems to be affected by treatment.

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We propose a more central role of BBB defects in the etiology of MS.

Prospective examination of anxiety and depression before and during confirmed and pseudoexacerbations in patients with multiple sclerosis

OBJECTIVE

This study was designed to determine whether pseudoexacerbations and confirmed MS exacerbations are preceded by or concurrent with increased anxiety or depressive symptoms.

METHODS

This was a secondary analysis of 121 patients with MS who were observed for 48 weeks during a randomized controlled trial. Participants completed monthly self-reports on depressive and anxiety symptoms. Patient-reported exacerbations were assessed through a telephone-administered symptom checklist and neurologic examination.

RESULTS

Both pseudoexacerbations and confirmed exacerbations were associated with concurrent somatic depressive (β = .16 and β = .33, respectively; p values < .05), affective depressive (β = .17 [p = .02] and β = .12 [p = .06]), and anxiety symptoms (β = .24 and β = .20, p values < .01), controlling for baseline symptoms. Preexisting somatic and affective depressive symptoms predicted amplified relationships between concurrent confirmed exacerbations and these symptoms (β = .19 and β = .20, respectively; p values < .01). A standard deviation increase in anxiety symptoms relative to baseline predicted subsequent onset of pseudoexacerbations (odds ratio = 1.54, p = .02), whereas increased somatic depressive symptoms predicted confirmed exacerbations (odds ratio = 1.59, p = .01).

CONCLUSIONS

Patients with MS experiencing pseudoexacerbations or confirmed exacerbations should be assessed and monitored for depressive and anxiety symptoms, and confirmed exacerbations are particularly concerning in patients with a history of depression. The psychological or psychiatric antecedents of MS exacerbations generate new hypotheses on etiologies of confirmed exacerbations and pseudoexacerbations.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00147446.

Cervical disk pathology in patients with multiple sclerosis: two case reports

BACKGROUND AND PURPOSE

A patient with multiple sclerosis (MS) may be seen by a physical therapist for evaluation before the MS diagnosis is definitively made, after a relapse, or during a progression. The diagnosis of MS should be part of the differential diagnosis if the symptoms of a patient with neurological issues fit the pattern of a progressive disease. Multiple sclerosis can affect any part of the central nervous system. Cervical pathology can be confused with relapsing symptoms of MS. The purpose of this case report is to demonstrate how easily cervical pathology can be overlooked in a patient with MS.

CASE DESCRIPTION

Two case reports of patients with relapsing MS are presented. Both patients were referred for physical therapy after not responding to standard treatment with intravenous methylprednisolone. One patient reported multiple falls and complained of increasing cervical pain and spasm, fatigue, bouts of diplopia, and difficulty ambulating. The other patient complained of headaches, visual disturbances, and cervical pain with radicular symptoms. Contrast magnetic resonance imaging (MRI) did not reveal new MS lesions or the extension of old MS lesions. The cervical herniations in the first patient, not previously documented, were old. The bulging disks in the second patient, seen in a previous study, were unchanged. The MRI findings did not support the diagnosis of acute inflammatory MS or acute cervical pathology.

OUTCOMES

Both patients responded to physical therapy intervention once the cervical symptoms were directly addressed. As the cervical pain and spasm decreased, the relapsing MS symptoms of dysmetria, balance disturbance, and ataxic gait began to diminish. In both patients, eye function was slow to recover, with persistent impairment. Both patients returned to their premorbid activity and socialization level.

DISCUSSION

Cervical disk disease should be considered in the differential diagnosis when a patient with MS has a history of trauma and displays abnormal postures, spastic weakness, and changes in pain complaints. In these 2 cases, treating the cervical pathology in addition to the MS symptoms provided the most effective approach for functional improvement.

Increased risk of multiple sclerosis after traumatic brain injury: a nationwide population-based study

The etiology of multiple sclerosis (MS) is still not well known. Previous data show conflicting results regarding the association between MS and prior brain trauma. This study aims to investigate the risk for MS following a traumatic brain injury (TBI) using a large-scale cohort study design. This study used data from the National Health Insurance Research Database. A total of 72,765 patients with TBI were identified and included as the study cohort, and 218,295 randomly selected subjects were matched with the study cohort by sex and age as controls. We traced each patient individually for a 6-year period from their index health care utilization to identify those who received a subsequent diagnosis of MS. We used the Kaplan-Meier method and the log-rank test to compare the difference in 6-year MS-free survival rates between the two groups. Stratified Cox proportional hazard regressions were computed to compare the risk of developing MS for these two cohorts. Patients with TBI had a higher incidence of MS during the 6-year period than the comparison group (0.055% versus 0.037%). After excluding cases who died from non-MS causes, stratifying for hospitalization of cases as a proxy for severity, and adjusting for monthly income and geographic region of the community in which the patient resided, the hazard ratio (HR) of MS for patients with hospital-treated TBI injuries was 1.97 (95% CI 1.31,2.93, p<0.01) that of patients without TBI during the 6-year follow-up period after index health care use. Our study concludes that patients with TBI are at higher risk for subsequent MS over a 6-year follow-up period.

Head injury is not a risk factor for multiple sclerosis: a prospective cohort study

Background

The idea of physical trauma being involved in the causation of multiple sclerosis (MS) had been discussed since the earliest description of the illness. Despite the ongoing debate, the proposed association between physical and especially head trauma and MS failed to be proved or to be refuted conclusively.

Objective

To determine whether head trauma is associated with an increased risk of developing MS.

Method

A cohort of 150,868 subjects, 95,111 men, and 55,757 women registered in the National Danish Patient Registry with hospital admission for cerebral concussion, contusion, or skull fracture between 1977 and 1992, aged under 55, was selected. This trauma cohort was linked with the Danish MS Registry and followed up to the end of 1999 to retrieve subjects who had onset of MS after the year of the head trauma. We calculated the expected number of subjects, who, under a null-hypothesis, would subsequently develop MS, by using population age-, year-, and sex-specific MS-incidence densities from the Danish MS Registry.

Results

For men and women combined, the observed to expected number of MS cases (possible cases included) with onset after the head injury was 182/193.6 (standardized incidence ratio [SIR], 0.94; 95% CI, 0.81–1.09) and for possible MS excluded, 171/164.7 (SIR, 1.04; 95% CI, 0.89–1.21). In an analysis of a sub-cohort of 16,425 subjects with severe trauma (contusion, traumatic cerebral hemorrhage, and base or skull fracture), the observed to expected numbers, including possible MS, were 15/15.3 (SIR, 0.98; 95% CI, 0.55–1.62) and with possible MS excluded, 13/12.9 (SIR, 1.01; 95% CI, 0.53–1.73). As for the total group and for any of the subgroups and for men and women separately, none of the SIRs differed statistically significantly from unity. Neither were there any trends, which could be missed by type II errors.

Conclusion

Head injury of any severity does not affect the risk of acquiring MS later in life.

Multiple sclerosis: etiology and treatment strategies

OBJECTIVE

To review the etiology and treatment strategies for multiple sclerosis (MS).

DATA SOURCES

Published information on MS and targeted treatment strategies extending back to 1955. The search terms multiple sclerosis and pathology, prevalence, genetics, and each of the common symptoms of MS were used.

STUDY SELECTION

Seventy-two studies were reviewed based on level 1, 2, and 3 search strategies.

DATA EXTRACTION

Level 1 search strategy targeted evidence-based trials of large sample size (N > 100) with a randomized, double-blind, placebo-controlled design. A level 2 search targeted additional trials with some of the traits of evidence-based trials. A level 3 search compared key findings in reports of very small (N < 15) poorly designed trials with the results of well-designed trials.

DATA SYNTHESIS

MS affects each patient differently, making a definitive diagnosis and management of symptoms very difficult. Effective symptom management requires an interprofessional team approach.

CONCLUSION

Despite all the research dedicated to this disease, there is still no cure. The treatments currently available function at best only to slow the disease progression and mitigate symptoms. Using the skills and knowledge available from a team of health care professionals will help patients navigate the trials and tribulations that follow throughout a life with MS.

Mechanisms and implications of adaptive immune responses after traumatic spinal cord injury

Traumatic spinal cord injury (SCI) in mammals causes widespread glial activation and recruitment to the CNS of innate (e.g. neutrophils, monocytes) and adaptive (e.g. T and B lymphocytes) immune cells. To date, most studies have sought to understand or manipulate the post-traumatic functions of astrocytes, microglia, neutrophils or monocytes. Significantly less is known about the consequences of SCI-induced lymphocyte activation. Yet, emerging data suggest that T and B cells are activated by SCI and play significant roles in shaping post-traumatic inflammation and downstream cascades of neurodegeneration and repair. Here, we provide neurobiologists with a timely review of the mechanisms and implications of SCI-induced lymphocyte activation, including a discussion of different experimental strategies that have been designed to manipulate lymphocyte function for therapeutic gain.

Selective association of multiple sclerosis with infectious mononucleosis

Previous studies have suggested an association between multiple sclerosis (MS) and infectious mononucleosis (IM) but data on the exact strength of this association or its selectivity have been conflicting. In this study we have evaluated the association between MS and a variety of common childhood infections and afflictions in a large population-based case-control study involving 2,877 MS cases and 2,673 controls in the Netherlands. We examined the frequency of different common infections and afflictions before the age of 25 and the age at which they occurred, using a self-administered questionnaire. The Odds ratios (ORs) for the occurrence of a variety of clinically manifest common childhood infections including rubella, measles, chicken pox and mumps before the age of 25 for MS cases versus controls ranged between 1.14 and 1.42, values similar to those for irrelevant probe variables used to reveal recall bias. In contrast, the OR for clinically manifest IM in MS cases versus controls, corrected for demographic variables, was 2.22 (95% confidence interval 1.73 - 2.86; P < 0.001). The average age of onset of IM in the population of MS cases (16.5 years) did not differ from controls (16.8 years). Our data confirm previous much smaller studies to show that the risk for MS is significantly enhanced by prior IM, and extend those previous data by showing that this association is far stronger than with other common childhood infections or afflictions.

Pain and traumatic brain injury

For the patient who has sustained traumatic brain injury (TBI), understanding the problem and listening to and believing the patient are prerequisites to treating pain. Because the information provided may be limited, communication skills problematic, and consistency variable, the challenge of treating individuals with TBI and pain can be daunting. Most painful conditions after TBI involve the musculoskeletal system; however, in conditions that are neurologically based, a careful and well-organized neurologic examination can be helpful to direct one's attention toward ordering the appropriate tests and treatments. The primary focus for helping patients with pain involves not only understanding the problem and assisting with symptom relief but also providing the opportunity to improve their functioning, physically and cognitively.

Tolerogenic effect of fiber tract injury: reduced EAE severity following entorhinal cortex lesion

Despite transient, myelin-directed adaptive immune responses in regions of fiber tract degeneration, none of the current models of fiber tract injuries evokes disseminated demyelination, implying effective mechanisms maintaining or re-establishing immune tolerance. In fact, we have recently detected CD95L upregulation accompanied by apoptosis of leukocytes in zones of axonal degeneration induced by entorhinal cortex lesion (ECL), a model of layer-specific axonal degeneration. Moreover, infiltrating monocytes readily transformed into ramified microglia exhibiting a phenotype of immature (CD86+/CD80-) antigen-presenting cells. We now report the appearance of the axonal antigen neurofilament-light along with increased T cell apoptosis and enhanced expression of the pro-apoptotic gene Bad in cervical lymph nodes after ECL. In order to test the functional significance of such local and systemic depletory/regulatory mechanisms on subsequent immunity to central nervous system antigens, experimental autoimmune encephalomyelitis was induced by proteolipid protein immunization 30 days after ECL. In three independent experiments, we found significantly diminished disease scores and infiltrates in lesioned compared to sham-operated SJL mice. This is consistent with a previous meta-statistical analysis (Goodin et al. in Neurology 52:1737-1745, 1999) rejecting the O-hypothesis that brain trauma causes or exacerbates multiple sclerosis. Conversely, brain injuries may involve long-term tolerogenic effects towards brain antigens.

Multiple sclerosis trait: the premorbid stage of multiple sclerosis. A hypothesis

The unexpectedly low rate of concordance in monozygotic (MZ) twins with multiple sclerosis (MS) suggests that they share a systemic condition called the multiple sclerosis trait. This trait constitutes the premorbid stage of the disease and is quite distinct from asymptomatic MS. It results from the action of an antigenic challenge to the immune system of a genetically susceptible person but is short of producing lesions of the central nervous system parenchyma; in fact, the disease may never develop in people with the trait. An environmental triggering event is required to transform the trait into the disease. The discordance of clinical involvement and magnetic resonance images in MZ twins reflects differences in the effect of environmental influences.

Self-tolerance in the immune privileged CNS: lessons from the entorhinal cortex lesion model

Upon peripheral immunization with myelin epitopes, susceptible rats and mice develop T cell-mediated demyelination similar to that observed in the human autoimmune disease multiple sclerosis (MS). In the same animals, brain injury does not induce autoimmune encephalomyelitis despite massive release of myelin antigens and early expansion of myelin specific T cells in local lymph nodes, indicating that the self-specific T cell clones are kept under control. Using entorhinal cortex lesion (ECL) to induce axonal degeneration in the hippocampus, we identified possible mechanisms of immune tolerance after brain trauma. Following ECL, astrocytes upregulate the death ligand CD95L, allowing apoptotic elimination of infiltrating activated T cells. Myelin-phagocytosing microglia express MHC-II and the costimulatory molecule CD86, but lack CD80, which is found only on activated antigen presenting cells (APCs). Restimulation of invading T cells by such immature APCs (e.g. CD80 negative microglia) may lead to T cell anergy and/or differentiation of regulatory/Th3-like cells due to insufficient costimulation and presence of high levels of TGF-beta and IL-10 in the CNS. Thus, T cell -apoptosis, -anergy, and -suppression apparently maintain immune tolerance after initial expansion of myelin-specific T lymphocytes following brain injury. This view is supported by a previous metastatistical analysis which rejected the hypothesis that brain trauma is causative of MS (Goddin et al., 1999). However, concomitant trauma-independent proinflammatory signals, e.g., those evoked by clinically quiescent infections, may trigger maturation of APCs, thus shifting a delicate balance from immune tolerance and protective immune responses to destructive autoimmunity.

Does trauma trigger multiple sclerosis? 1: A controversy

The potential role of trauma in the development of multiple sclerosis is important but controversial. Patients commonly ask about this and it has important medicolegal ramifications. In addressing such issues this article will consider both physical and psychological trauma, examine pathogenic mechanisms, and discuss the evidence for and against a relationship.

Vascular endothelial growth factor is expressed in multiple sclerosis plaques and can induce inflammatory lesions in experimental allergic encephalomyelitis rats

The active lesions in multiple sclerosis (MS) are characterized by blood-brain-barrier (BBB) breakdown, upregulation of adhesion molecules on capillary endothelial cells, and perivascular inflammation, suggesting that altered vessel permeability and activated endothelial cells are involved in the pathogenesis of the disease. Vascular endothelial growth factor (VEGF) mediates multiple aspects of blood vessel physiology, including regulation of growth, permeability, and inflammation. To investigate a possible relationship between VEGF expression and CNS autoimmune disease, we examined VEGF expression in MS plaques compared to normal white matter by immunohistochemistry and in situ hybridization. VEGF expression was consistently upregulated in both acute and chronic MS plaques. We also examined VEGF expression during the course of experimental allergic encephalomyelitis (EAE) in rats. VEGF-positive cells with astrocytic morphology increased in the spinal cord during the development of EAE and were found in association with inflammatory cells. Furthermore, intracerebral infusion of VEGF in animals previously immunized with myelin basic protein induced an inflammatory response in the brain, whereas infusion of vehicle, or infusion of VEGF in naive animals, did not. These results suggest that overexpression of VEGF may exacerbate the inflammatory response in autoimmune diseases of the CNS by inducing focal BBB breakdown and migration of inflammatory cells into the lesions.

A case-control study of the association between socio-demographic, lifestyle and medical history factors and multiple sclerosis

OBJECTIVE

The etiology of multiple sclerosis (MS) remains poorly understood. Socio-demographic characteristics may play important roles in its development.

METHODS

In a case-control study of MS, a total of 200 newly diagnosed MS patients and 202 frequency age- and sex-matched controls were studied.

RESULTS

A direct and significant association was observed between cigarette smoking and the risk of MS. Higher education seemed to reduce the risk of MS. Contact with cats was inversely associated with MS, particularly in males, whereas contact with caged birds increased the risk significantly, especially in females. A strong family aggregation of MS was observed among cases. A past history of trauma and eye problems appeared to pose a high risk of MS. Cases had a significant family history of eye problems, mumps, measles, rubella, cancer and auto-immune diseases.

CONCLUSION

If smoking and history of certain infectious diseases increase the risk of MS significantly, they could be modified and avoided, thereby reducing the likelihood of being afflicted by MS.

Pathological CNS autoimmune disease triggered by traumatic spinal cord injury: implications for autoimmune vaccine therapy

Lymphocytes respond to myelin proteins after spinal cord injury (SCI) and may contribute to post-traumatic secondary degeneration. However, there is increasing evidence that autoreactive T-lymphocytes may also convey neuroprotection and promote functional recovery after CNS injury. To clarify the role of myelin autoreactive lymphocytes after SCI, we performed contusion injuries in the thoracic spinal cord of transgenic (Tg) mice in which >95% of all CD4+ T-lymphocytes are reactive with myelin basic protein (MBP). We observed significantly impaired recovery of locomotor and reflex function in Tg mice compared with non-Tg (nTg) littermates. Measures of functional impairment in Tg mice correlated with significantly less white matter at the injury site, and morphometric comparisons of injured Tg and nTg spinal cords revealed increased rostrocaudal lesion expansion (i.e., secondary degeneration) in Tg mice. Rostrocaudal to the impact site in SCI-nTg mice, demyelination was restricted to the dorsal funiculus, i.e., axons undergoing Wallerian degeneration. The remaining white matter appeared normal. In contrast, lymphocytes were colocalized with regions of demyelination and axon loss throughout the white matter of SCI-Tg mice. Impaired neurological function and exacerbated neuropathology in SCI-Tg mice were associated with increased intraspinal production of proinflammatory cytokine mRNA; neurotrophin mRNA was not elevated. These data suggest that endogenous MBP-reactive lymphocytes, activated by traumatic SCI, can contribute to tissue injury and impair functional recovery. Any neuroprotection afforded by myelin-reactive T-cells is likely to be an indirect effect mediated by other non-CNS-reactive lymphocytes. Similar to the Tg mice in this study, a subset of humans that are genetically predisposed to autoimmune diseases of the CNS may be adversely affected by vaccine therapies designed to boost autoreactive lymphocyte responses after CNS trauma. Consequently, the safe implementation of such therapies requires that future studies define the mechanisms that control T-cell function within the injured CNS.

Acute cervical hyperextension-hyperflexion injury may precipitate and/or exacerbate symptomatic multiple sclerosis

We report here 39 cases in which definite multiple sclerosis (MS) was precipitated or exacerbated by specific hyperextension-hyperflexion cervical cord trauma. The worsening or onset of the symptomatic disease bore a striking temporal relationship to the focal injury. Our data suggests that central nervous system (CNS)-specific acute physical trauma such as cervical cord hyperextension-hyperflexion injury may aggravate latent clinical symptoms in MS. The deterioration of MS bore no direct relationship with the severity of neck injury. Possible pathogenic mechanisms of focal CNS-specific trauma aggravating the course of asymptomatic or benign MS are discussed. This may have implications in improving our understanding of the factors that may modify the clinical course of MS.

Recommendations for physical activity in patients with multiple sclerosis

For many years, patients with multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system, have been advised to avoid exercise. MS is believed to be autoimmune in origin, mediated by activated T cells which penetrate the blood-brain barrier and attack myelin. The pathophysiology, with respect to function is an impairment of saltatory conduction, specifically, slowing of conduction speed and/or conduction block. Symptoms can temporarily worsen on exposure to heat or during physical exercise. Exercise programmes must be designed to activate working muscles but avoid overload that results in conduction block. Fatigue, often severe, affects about 85% of MS patients and, along with motor and sensory symptoms, results in decreased mobility and reduced quality of life. Physical activity and recreation are reduced in patients with MS. Before developing recommendations, physical activity patterns and the physical effects of MS should be assessed in individual patients. Patients may then be functionally classified. Physical activity can also be classified in a pyramid structure, with the most basic functions forming the base and the most integrated functions on top. The muscular fitness pyramid progresses through passive range of motion, active resistive, specific strengthening and integrated strength exercises Overall physical activity may be increased according to functional level by performing activities of daily living, incorporating inefficiencies into daily living, pursuing more active recreation and eventually developing a structured exercise programme. The importance of the proper exercise environment, balance and coordination issues and factors related to adherence are discussed.

Essential fatty acid preparation improves biochemical and cognitive functions in experimental allergic encephalomyelitis rats

This study examined the possible effects of a novel mixture of fatty acids, SR-3 (a specific ratio of alpha-linolenic acids), on brain biochemistry and on learning deficits induced by injection of an agent that induces experimental allergic encephalomyelitis. Treatment with SR-3 caused a decrease in myelin and changes in the fatty acid profile of brain synaptosomes, and a learning deficit. Eighteen days of treatment with SR-3 reversed the biochemical and learning deficit significantly, but did not restore them to normal levels. We propose that, most probably, the main action of SR-3 is the modulation of the cholesterol level, which in turn causes the modulation of the fatty acid profile and enhances learning by allowing improved neuronal communication.