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PubMed2004

Cerebral demyelination in Wegener's granulomatosis.

A 38-year-old woman with a history of a granulomatous lesion of the nose, developed blurred vision, ataxic gait, and spastic tetraparesis. The presence of demyelination on the brain MRI led to the diagnosis of cerebral demyelination associated with Wegener's granulomatosis. Pulse cyclophosphamide administration resulted in some clinical of improvement of her condition. Demyelinating lesions seen in Wegener's have been ascribed to multiple sclerosis, but in this case, they are much more reminiscent of disseminated encephalomyelitis (DEM). The immunological challenge of the underlying disease, may, in the genetically susceptible person, presumably trigger the appearance of MS lesions. Wegener's granulomatosis must be considered in the differential diagnosis of MS.

Adult↗
PubMed2005

CNS demyelination in autoimmune diseases.

Autoimmune diseases represent a diverse group of disorders that have generally of unknown etiology and poorly understood pathogenesis. They may be organ-specific or systemic, giving rise to overlapping syndromes; more than one autoimmune disease may occur in the same patient. Numerous case reports have documented that multiple sclerosis (MS) may be present concurrently with other autoimmune diseases, most commonly rheumatoid arthritis, autoimmune thyroid disease, type I diabetes mellitus and pernicious anemia. Case reports of disseminated encephalomyelitis (DEM) coincidental with other autoimmune diseases are rare. Many of systemic autoimmune diseases cause central nervous system (CNS) demyelination and are frequently then diagnosed as MS, whereas they often are instances of DEM, the result of vascular, granulomatous or postinfectious manifestations. We have reviewed 15 patients with autoimmune diseases and CNS demyelination in order to determine the nature of the demyelinating process.

Adolescent↗
PubMed2004

Mycobacterium leprae-induced demyelination: a model for early nerve degeneration.

The molecular events that occur at the early phase of many demyelinating neurodegenerative diseases are unknown. A recent demonstration of rapid demyelination and axonal injury induced by Mycobacterium leprae provides a model for elucidating the molecular events of early nerve degeneration which might be common to neurodegenerative diseases of both infectious origin and unknown etiology. The identification of the M. leprae-targeted Schwann cell receptor, dystroglycan, and its associated molecules in myelination, demyelination and axonal functions suggests a role for these molecules in early nerve degeneration.

Animals↗
PubMed2006

Remyelination after cuprizone-induced demyelination in the rat is stimulated by apotransferrin.

Twenty-one-day-old Wistar rats were fed a diet containing 0.6% cuprizone for 2 weeks. Studies carried out after withdrawal of cuprizone showed histological evidences of marked demyelination in the corpus callosum. Biochemical studies of isolated myelin showed a marked decrease in myelin proteins, phospholipids, and galactocerebrosides as well as a marked decrease in myelin yield. Treatment of these animals with a single intracranial injection of 350 ng of apotransferrin at the time of withdrawal of cuprizone induced a marked increase in myelin deposition resulting in a significantly improved remyelination, evaluated by histological, immunocytochemical, and biochemical parameters, in comparison to what was observed in spontaneous recovery. Immunocytochemical studies of cryotome sections to analyze developmental parameters of the oligodendroglial cell population at the time of termination of cuprizone and at different times thereafter showed that in the untreated animals, there was a marked increase in the number of NG2-BrdU-positive precursor cells together with a marked decrease in MBP expression at the peak of cuprizone-induced demyelination. As expected, the amount of precursor cells decreased markedly during spontaneous remyelination and was accompanied by an increase in MBP reactivity. In the apotransferrin-treated animals, these phenomena occurred much faster, and remyelination was much more efficient than in the untreated controls. The results of this study suggest that apotransferrin is a very active promyelinating agent which could be important for the treatment of certain demyelinating conditions.

Analysis of Variance↗
PubMed2006

Inflammation, demyelination, neurodegeneration and neuroprotection in the pathogenesis of multiple sclerosis.

Although axonal loss has been observed in demyelinated multiple sclerosis (MS) lesions, there has been a major focus on understanding mechanisms of demyelination. However, identification of markers for axonal damage and development of new imaging techniques has enabled detection of subtle changes in axonal pathology and revived interest in the neurodegenerative component of MS. Axonal loss is generally accepted as the main determinant of permanent clinical disability. However, the role of axonal loss early in disease or during relapsing-remitting disease is still under investigation, as are the interactions and interdependency between inflammation, demyelination, neurodegeneration and neuroprotection in the pathogenesis of MS.

Animals↗
PubMed2004

An autopsied case of Sjogren's syndrome with massive necrotic and demyelinating lesions of the cerebellar white matter.

A 69-year-old woman developed subacute cerebellar ataxia and tremors in all four limbs in April 1996. Laboratory examination showed elevated antibodies against Ro and La. Head magnetic resonance imaging showed T(2) high-intensity lesions in the cerebellar white matter bilaterally and later in the pons. In April 2000, she died of multiple organ failure with incidental colon cancer. The autopsy showed atrophic parotid glands with an accumulation of lymphocytes around the ducts, confirming the diagnosis of Sjogren's syndrome histopathologically. The neuropathological examination revealed severe necrotic lesions in the cerebellar white matter bilaterally with several foci of perivenous demyelination in the periphery of the lesions and similar demyelinated areas in the pons. Immunohistochemistry with anti-JC virus antibody demonstrated no positive inclusions. A single focus of granulomatous arteritis was observed in one subarachnoid artery. The combination of Sjogren's syndrome, granulomatous angitis, and foci of perivenous demyelination suggests that an autoimmune mechanism played an important role in causing the necrotic lesions in the cerebellar white matter in this case.

Aged↗
PubMed2005

The therapeutic use of stem cells for myelin repair in autoimmune demyelinating disorders.

Spontaneous remyelination occurs in multiple sclerosis (MS) patients. However, this process is not robust enough to promote a functional and stable recovery of the myelin architecture in demyelinated areas of the central nervous system (CNS). As a consequence of this incomplete reparative process, the disease invariably progresses and patchy areas of demyelination-in which axonal damage and/or loss is a constant accompanying factor-increase over time and lead to the accumulation of irreversible neurological deficits. Thus, the development of cell-based therapies aimed to promote multifocal remyelination in MS represents one of the most challenging areas of investigation. Several cell-replacement strategies have been developed in the last few years. However, most of these therapeutic approaches-although consistently able to form new myelin sheaths around the transplantation site-are unrealistic owing to the multifocality of the demyelinating process and the inability to in vitro growth and differentiate large number of myelin-forming cells. Recently, promising cell-replacement therapies based on the use of stem cells have been proposed. However, before envisaging any potential human applications of such therapies we need to confront with some preliminary and still unsolved questions: (i) the ideal stem cell source for transplantation, (ii) the route of cell administration, (iii) the differentiation and persistence of stem cells into the targeted tissue and, last but not least, (iv) the functional and long-lasting integration of transplanted cells into the host tissue.

Animals↗
PubMed2005

Recurrent tumefactive demyelination in a child.

A 13-year-old female presented with two episodes of hemiplegia and hemianopia involving opposite sides, each time associated with seizures. On both occasions, the magnetic resonance (MR) scan showed a giant demyelinating, peripherally enhancing lesion with mass effect. MR spectroscopy (MRS) was indistinguishable from a tumor. At the first episode, she had undergone tumor decompression but the histopathology revealed an acute demyelinating lesion with no evidence of tumor. Each time there was partial clinical recovery and resolution of the radiological lesion, the patient having received corticosteroids during both of the episodes. She also developed hemiballismus postoperatively which resolved on withdrawing phenytoin. It is suggested that a trial of corticosteroids be given in suspected tumefactive demyelinating lesions, although they may be indistinguishable from a tumor.

Adolescent↗
PubMed2004

First episode of acute CNS inflammatory demyelination in childhood: prognostic factors for multiple sclerosis and disability.

OBJECTIVES: To evaluate prognostic factors for second attack and for disability in children presenting with an initial episode of central nervous system (CNS) demyelination. STUDY DESIGN: A cohort of 296 children having a first episode of acute CNS inflammatory demyelination was studied by survival analysis. RESULTS: The average follow-up was 2.9+/-3 years. At the end of the follow-up, 57% of patients had a diagnosis of multiple sclerosis (MS), 29% had a monophasic acute disseminated encephalomyelitis, and 14% had a single focal episode. The rate of a second attack was (1). higher in patients with age at onset >or=10 years (hazard ratio, 1.67; 95% CI, 1.04-2.67), MS-suggestive initial MRI (1.54; 1.02-2.33), or optic nerve lesion (2.59; 1.27-5.29); and (2). lower in patients with myelitis (0.23; 0.10-0.56) or mental status change (0.59; 0.33-1.07). Of patients with a second attack, 29% had an initial diagnosis of acute disseminated encephalomyelitis. At the end of the follow-up period, 90% of patients had no or minor disability. Occurrence of severe disability was associated with a polysymptomatic onset (3.25; 1.16-11.01), sequelae after the first attack (26.65; 9.42-75.35), further relapses (1.49; 1.16-1.92), and progressive MS (3.57; 1.21-8.72). CONCLUSIONS: Risk of second attack of CNS demyelination is higher in older patients and lower in patients with mental status change. Risk of disability is higher in polysymptomatic and relapsing patients.

Acute Disease↗
PubMed2004

Increased expression of Nkx2.2 and Olig2 identifies reactive oligodendrocyte progenitor cells responding to demyelination in the adult CNS.

Within the adult CNS, a quiescent population of oligodendrocyte progenitor cells (OPCs) become activated in response to demyelination and give rise to remyelinating oligodendrocytes. During development, OPC differentiation is controlled by several transcription factors including Olig1 and Olig2, and Nkx2.2. We hypothesized that these genes may serve similar functions in activated adult OPCs allowing them to become remyelinating oligodendrocytes and tested this hypothesis by examining their expression during the remyelination of a toxin-induced rodent model of demyelination. During the acute phase of demyelination, OPCs within the lesion increased their expression of Nkx2.2 and Olig2, two transcription factors that in combination are critical for oligodendrocyte differentiation during developmental myelination. This activation was not associated with increases in Sonic hedgehog (Shh) expression, which does not appear essential for CNS remyelination. Consistent with a role in the activation and differentiation of OPCs, these increases were delayed in old adult animals where the rate of remyelination is slowed. Our data suggest the hypothesis that increased expression of Nkx2.2 and Olig2 plays a critically important role in the differentiation of adult OPCs into remyelinating oligodendrocytes and that these genes may present novel targets for therapeutic manipulation in cases where remyelination is impaired.

Animals↗
PubMed2005

Determination of relaxation characteristics during preacute stage of lysophosphatidyl choline-induced demyelinating lesion in rat brain: an animal model of multiple sclerosis.

Relaxation time measurements were carried out during the preacute stage of lesion progression in an animal model of demyelination created in the internal capsule (ic) area of the rat brain using lysophosphatidyl choline (LPC). T1 and T2 were determined both before and after 36 h of lesion creation. Histology carried out on the rats after MR measurements showed focal demyelinating lesion and surrounding edema with prominent infiltration of inflammatory cells. Both T1 and T2 were statistically higher for the lesion compared to that determined before lesion creation. Percentage increase in T2 was found to be higher by approximately 45% compared to before lesion creation while T1 showed about 25% increase. Increase in T1 and T2 may be attributed to the early acute inflammatory response due to LPC. The beginning of the inflammatory response following LPC injection may also be a contributing factor. The study demonstrates that the quantitative estimate of MR relaxation provides useful information on the pathological events occurring during the early phase of the progression of demyelination.

Animals↗
PubMed2004

Dynamics of MRI lesion development in an animal model of viral-induced acute progressive CNS demyelination.

Theiler's murine encephalitis virus (TMEV) infection in mice is an established model of CNS demyelinating diseases. The aim of the study was to determine the chronological pattern of lesion development in this model of monophasic fulminant demyelinating disease. We followed six highly susceptible interferon-gamma receptor knockout mice with serial in vivo brain magnetic resonance imaging (MRI) studies to determine changes in overall T2 lesion load and gadolinium enhancement. Altogether, 163 individual lesions were followed over 52 days. The number of lesions increased linearly with time. Four chronological patterns of lesion development were seen: (a) expanding lesions (48.5% of all lesions, 54.05% volume contribution); (b) expanding-retracting lesions (20.85% of all lesions, 15.03% volume contribution); (c) fluctuating lesions (16.6% of all lesions, 28.8% volume contribution); (d) stable lesions (14.05% of all lesions, 2.12% volume contribution). Gadolinium enhancement was not seen in the evolution of every lesion. Enhancement was both time- and lesion type-dependent. Early in the disease course (<43 days after infection), enhancement was almost always seen, later on (>43 days after infection) it was only seen in 8% of new lesions. All of fluctuating, 85.3% of expanding, 83.5% of expanding-retracting, and 56.5% of stable lesions were associated with gadolinium enhancement. We conclude that the MRI features of TMEV-induced demyelination in this model showed four unique chronological patterns, and inconsistent gadolinium enhancement. These novel findings may provide new insights into the pathogenesis of acute fulminant multiple sclerosis (MS).

Algorithms↗
PubMed2004

Reversible demyelination, blood-brain barrier breakdown, and pronounced neutrophil recruitment induced by chronic IL-1 expression in the brain.

Interleukin-1beta (IL-1) expression is associated with a spectrum of neuroinflammatory processes related to chronic neurodegenerative diseases. The single-bolus microinjection of IL-1 into the central nervous system (CNS) parenchyma gives rise to delayed and localized neutrophil recruitment, transient blood-brain barrier (BBB) breakdown, but no overt damage to CNS integrity. However, acute microinjections of IL-1 do not mimic the chronic IL-1 expression, which is a feature of many CNS diseases. To investigate the response of the CNS to chronic IL-1 expression, we injected a recombinant adenovirus expressing IL-1 into the striatum. At the peak of IL-1 expression (days 8 and 14 post-injection), there was a marked recruitment of neutrophils, vasodilatation, and breakdown of the BBB. Microglia and astrocyte activation was evident during the first 14 days post-injection. At days 8 and 14, extensive demyelination was observed but the number of neurons was not affected by any treatment. Finally, at 30 days, signs of inflammation were no longer present, there was evidence of tissue reorganization, the BBB was intact, and the process of remyelination was noticeable. In summary, our data show that chronic expression of IL-1, in contrast to its acute delivery, can reversibly damage CNS integrity and implicates this cytokine or downstream components as major mediators of demyelination in chronic inflammatory and demyelinating diseases.

Adenoviridae↗
PubMed2003

Neurotrophin-3 specifically increases mature oligodendrocyte population and enhances remyelination after chemical demyelination of adult rat CNS.

In human central nervous system (CNS) demyelinating diseases, spontaneous remyelination is often incomplete. Therefore, we have tested whether neutrotrophin-3 (NT-3) accelerates CNS myelin repair after a chemically-induced demyelination. One group of adult rats was injected in the corpus callosum (CC) with 1 microl of 1% lysophosphatidylcholine (LPC) and 1 microl of NT-3 (1 microg/microl), and 15 days after injury (D15) remyelination was compared to control rats (receiving 1 microl of LPC+1 microl of vehicle buffer of NT-3). The demyelinated volume decreased by 56% in NT-3-treated rats at D15, and immunohistochemistry showed an increase in mature MBP(+) oligodendrocytes (OL) (+66%) in treated animals (whereas less mature (CNP(+)) OL were unchanged). Since less than 3% axons degenerate in this model, and as astrocytic gliosis was not modified, these data suggest that NT-3 acts directly on cells of the OL lineage to enhance remyelination in vivo.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed2003

More severe neurologic deficits in SJL/J male than female mice following Theiler's virus-induced CNS demyelination.

Although multiple sclerosis (MS) is more prevalent in women than men, male MS patients develop more severe clinical symptoms and deteriorate faster than female patients. We investigated the differences in CNS demyelinating disease between SJL/J male and female mice following Theiler's murine encephalomyelitis virus (TMEV) infection. Infected female mice had consistently higher serum levels of virus-specific IgG at 14 and 21 days and and 7 months postinfection, which resulted in less infectious virus in CNS. All male mice infected for 6 to 7 months developed paralysis, with 50% displaying bilateral posterior limb paralysis, whereas 77% of age-matched female mice were paralyzed, all displaying unilateral posterior limb paralysis. Male mice infected for 6 to 7 months performed up to threefold fewer spontaneous horizontal and vertical movements (activity box test) compared to infected age-matched females. In addition, infected male mice performed the coordination and balance (Rotarod) test at 27 +/- 4% of the expected level (expressed as a percentage of that of uninfected age-matched mice), whereas infected female mice performed at 41 +/- 5% of the expected level. Male mice had a small increase in the extent of spinal cord white matter demyelination analyzed at both 45 days and between 6 and 7 months postinfection. For individual male and female mice, the extent of demyelination had a negative linear relationship with the neurologic performances. The emergence of a disease paradigm similar to MS supports using the TMEV model to investigate molecular and genetic factors responsible for the gender dimorphism in MS and other autoimmune diseases.

Acute Disease↗
PubMed2001

Demyelination and axonal damage in a non-human primate model of multiple sclerosis.

The demyelinating plaque is the paradigmatic lesion of multiple sclerosis (MS), but only recently attention has been given to axonal damage and to its role in the pathophysiology of disease. Albeit the possible relevance of axonal loss in MS and its experimental models, the amount and timing of axonal sufferance has been addressed only in experimental autoimmune encephalomyelitis (EAE) of rodents. In this report we observed that, in the marmoset model of EAE, axonal damage occurs early during the demyelinating process as assessed by immunoreactivity for amyloid precursor protein (APP) and non-phosphorylated neurofilaments (SMI-32 positive) detected mostly in early active lesions compared to late active and normal appearing white matter. The rare occurrence of morphological features of axonal transection, such as APP or SMI-32 positive spheroids and swellings, as well as an increase of neurofilament density in the demyelinated axons without accumulation of electron dense organelles or osmiophilic bodies, at electron microscopy, suggests that early axonal damage may be, at least in part, a reversible process. These findings are of relevance for the development of therapies, which can protect axons and enhance their function and survival.

Amyloid beta-Protein Precursor↗
PubMed2001

Age of onset influences clinical features of chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP), which can occur through life from childhood to old age, presents a wide variety of clinical phenotypes. We investigated the relationship between age of onset and phenotype in 124 CIDP patients. Clinical symptoms, pathologic findings and electrophysiologic features were assessed according to age at onset: juvenile, younger than 20-years-old; adult, 20 to 64; and elderly, older than 64 (total n=124). Half of the juvenile group showed subacute progression initially, while most patients in the elderly group showed chronic insidious progression (chi(2)=23.2, P<0.0001). Motor dominant neuropathy was prominent in juveniles, while sensorimotor neuropathy was frequent in the elderly group (chi(2)=27.0, P<0.0001). A relapsing and remitting course predominated in the juvenile group (chi(2)=8.50, P=0.0143). Demyelinating and axonal degenerating features in sural nerve biopsy and in nerve conduction studies were common to three age groups. The subperineurial edema was more prominent in the juvenile and adult groups (P=0.006). Functional recovery was common in all three age groups, but was least apparent in the elderly group (P=0.00062). Demyelinating features in studies of nerve conduction and biopsy specimens was common to all three age groups, and was a useful diagnostic feature. Clinical features of CIDP differ by age of onset, which is a factor to consider in diagnosis, therapy, and prognosis.

Adult↗
PubMed2004

[Ion channels and demyelination: basis of a treatment of experimental autoimmune encephalomyelitis (EAE) by potassium channel blockers].

Voltage-gated potassium channels (Kv channels) are ion channels, openings of which provide an outward flow of potassium ions repolarising the cell. In neurons, Kv channels play a crucial role in action potential repolarisation and in shaping neuronal excitability. In non-excitable cells, such as T lymphocytes, Kv channels and calcium-activated K+ channels (KCa channels) determine the driving force for Ca2+ entry. During T cell activation the calcium entry depolarises the cell and increases the cytosolic calcium concentration, which in return activates Kv and KCa channels. K+ channel opening repolarises the cell and drives the membrane potential to a negative voltage. The roles of Kv channels in nervous and immune systems have been investigated here by means of a rat experimental autoimmune disease of the central nervous system, the experimental autoimmune encephalomyelitis (EAE). EAE is characterised clinically by paralysis, and pathologically by inflammatory cell infiltrations into the brain and the spinal cord. Among the inflammatory cells, T lymphocytes play a major role. Hence, EAE can be adoptively transferred into syngenic animals by the injection of T cells reactive to myelin antigens. During adoptive-EAE, somato-sensory evoked potentials recorded along the spinal tracts decrease in amplitude and axonal propagation is disrupted. We have analysed the consequences of Kv channels blockade by peptidyl toxins on central nerve conduction, on T cell activation and on the time course of EAE. In rat optic nerves, Kv channels have been identified up from postnatal day 1. Their blockade by kaliotoxin (a scorpion toxin) or by dendrotoxin-I (a snake toxin) enlarges the compound action potentials, demonstrating the participation of Kv channels to spike repolarisation. This effect disappears at adult age due to the sequestration of Kv channels under the myelin, in the paranodal regions. During acute demyelination by lysophosphatidyl-choline, the surface area of compound action potential decreased probably because conduction block occurred. Demyelination unmasked Kv channels, which are again accessible to toxins. Their blockade by dendrotoxin-I or kaliotoxin favoured a slow delayed conduction suggesting that those Kv channel blockers exert a neurological benefit during demyelinating diseases. In a T-cell line reactive to myelin basic protein antigen, which is used to adoptively transfer experimental autoimmune encephalomyelitis, Kv1.3 channels are constitutively expressed. Their blockade leads to a pronounced reduction of the T cell proliferative response, cytokine production and Ca2+ influx. In the rat, blockade of Kv1.3 inhibits the delayed type hypersensitivity response to myelin basic protein prevents and treats adoptive experimental autoimmune encephalomyelitis. Blockade of Kv channels alone or in combination with KCa channels improves the symptoms of the disease. These results demonstrate that K+ channel blockers displaying high selectivity are potent immunosuppressive agents with beneficial symptomatic effects in experimental autoimmune encephalomyelitis.

Action Potentials↗