Remyelination follows antibody-induced central nervous system demyelination

Adult CST-null mice maintain an increased number of oligodendrocytes

The galactolipids galactocerebroside and sulfatide have been implicated in oligodendrocyte (OL) development and myelin formation. Much of the early evidence for myelin galactolipid function has been derived from antibody and chemical perturbation of OLs in vitro. To determine the role of these lipids in vivo, we previously characterized mice lacking galactocerebroside and sulfatide and observed abundant, unstable myelin and an increased number of OLs. We have also reported that mice incapable of synthesizing sulfatide (CST-null) while maintaining normal levels of galactocerebroside generate relatively stable myelin with unstable paranodes. Additionally, Hirahara et al. (2004; Glia 45:269-277) reported that these CST-null mice also contain an increased number of OLs in the forebrain, medulla, and cerebellum at 7 days of age. Here, we further the findings of Hirahara et al. by demonstrating that the number of OLs in the CST-null mice is also increased in the spinal cord and that this elevated OL population is maintained through, at least, 7 months of age. Moreover, we show that the enhanced OL population is accompanied by increased proliferation and decreased apoptosis of oligodendrocytic-lineage cells. Finally, through ultrastructural analysis, we show that the CST-null OLs exhibit decreased morphological complexity, a feature that may result in decreased OL competition and increased OL survival.

In vitro and in vivo pharmacological models to assess demyelination and remyelination

In making a selection of cellular tools and animal models for generating screening assays in the search for new drugs, one needs to take into consideration the practicality of their use in the drug discovery process. Conducting high-throughput primary screens using libraries of small molecules, close to 1 million members in size, requires the generation of large numbers of cells which are easily acquired, reliably enriched, and reproducibly responsive to standard positive controls. These cells need to be similar in form and function to their counterparts in human disease. In vitro assays that can be mechanized by using robots can therefore save time and costs. In selecting in vivo models, consideration must be given to the species and strain of animal chosen, the appropriateness of the model to human disease, the extent of animal husbandry required during the in-life pharmacological assessment, the technical aspects of generating the model and harvesting the tissues for analyses, the cost of research tools in terms of time and money (demyelinating and remyelinating agents, amount of compound to be generated), and the length of time required for drug testing in the model. A consideration of the translational aspects of the in vivo model compared to those used in the clinic is also important. These themes will be developed with examples for drug discovery in the field of CNS demyelination and repair, specifically as it pertains to multiple sclerosis.

Galactolipids in the formation and function of the myelin sheath

Among the most abundant components of myelin are the galactolipids galactocerebroside (GalC) and sulfatide. In spite of this abundance, the roles that these molecules play in the myelin sheath are not well understood. Until recently, our concept of GalC and sulfatide functions had been principally defined by immunological and chemical perturbation studies that implicate these lipids in oligodendrocyte differentiation, myelin formation, and myelin stability. Recently, however, genetic studies have allowed us to re-analyze the functions of these lipids. Two laboratories have independently generated mice that are incapable of synthesizing either GalC or sulfatide by inactivating the gene encoding the enzyme UDP-galactose:ceramide galactosyltransferase (CGT), which is required for myelin galactolipid synthesis. These galactolipid-deficient animals exhibit a severe tremor, hindlimb paralysis, and display electrophysiological deficits in both the central and peripheral nervous systems. In addition, ultrastructural studies have revealed hypomyelinated white matter tracts with unstable myelin sheaths and a variety of myelin abnormalities including altered node length, reversed lateral loops, and compromised axo-oligodendrocytic junctions. Collectively, these observations indicate that cell-cell interactions, which are essential in the formation and maintenance of a properly functioning myelin sheath, are compromised in these galactolipid-deficient mice.

Reversal of an acute parkinsonian syndrome associated with multiple sclerosis by application of weak electromagnetic fields

The occurrence of movement disorders and particularly Parkinsonian symptoms is uncommon in patients with multiple sclerosis (MS) despite the rather frequent presence of demyelinating plaques in the basal ganglia. This disparity between the occurrence of clinical symptoms in MS and the distribution of demyelinating plaques suggests that impairment of neurotransmitter functions rather than demyelination may be critical to the clinical manifestations of the disease. A 48 year old woman with remitting-progressive MS developed a bilateral Parkinsonian syndrome in association with acute emotional stress which resolved after she received two brief successive extracerebral applications of low frequency picotesla flux density electromagnetic fields (EMFs). It is believed that in this patient Parkinsonism may have existed in a subclinical form and that acute stress, which previously has been shown to precipitate symptoms of Parkinson's disease, triggered the onset of Parkinsonism by further reducing dopaminergic and serotonergic neurotransmission in the basal ganglia. The rapid reversal of the Parkinsonian syndrome by EMFs was related to a presumed augmentation of dopaminergic and serotonergic neurotransmission which, on the basis of CSF studies, is reduced in chronic MS patients. The efficacy of EMFs in the treatment of Parkinson's disease had been documented previously but this report demonstrates that this treatment modality is beneficial also for the treatment of Parkinsonism developing in the setting of other neurodegenerative disorders.

Chronic relapsing multiple sclerosis: a case of rapid recovery by application of weak electromagnetic fields

A 54 year-old woman was diagnosed with multiple sclerosis (MS) in 1985 at the age of 45 after she developed diplopia, slurred speech, and weakness in the right leg. A Magnetic Resonance Imaging (MRI) scan obtained in 1985 showed several areas of plaque formation distributed in the periventricular white matter and centrum semiovale bilaterally. Coincident with slow deterioration in her condition since 1990 a second MRI scan was obtained in 1991 which showed a considerable increase in the number and size of plaques throughout both cerebral hemispheres, subcortical white matter, periventricularly and brainstem. In 1994, the patient received treatment with Interferon beta- 1b (Betaseron) for 6 months with no improvement in symptoms. However, following two successive extracranial applications of pulsed electromagnetic fields (EMFs) in the picotesla (pT) range each of 20 minutes duration the patient experienced an immediate improvement in symptoms most dramatically in gait, balance, speech, level of energy, swallowing, mood, and vision. On a maintenance program of 3 treatments per month the patient's only symptom is mild right foot and leg weakness. The report points to the unique efficacy of externally applied pT range EMFs in the symptomatic treatment of MS, indicates a lack of an association between the extent of demyelinating plaques on MRI scan and rate and extent of recovery in response to EMFs, and supports the notion that dysfunction of synaptic conductivity due to neurotransmitter deficiency particularly of serotonin (5-HT) contributes more significantly to the development of MS symptoms than the process of demyelination which clinically seems to represent an epiphenomenon of the disease.

Successful treatment of an acute exacerbation of multiple sclerosis by external magnetic fields

A 55 year old woman with multiple sclerosis presented with a 5 week history of an exacerbation of symptoms. Prominent among these symptoms was trigeminal neuralgia, migraine headaches, blurring of vision, and ataxia of gait. While treatment with carbamazepine (TegretolR) (800 mg/d) and oral prednisolone (15 mg/d) over a 4 week period produced no improvement in symptoms, externally applied magnetic fields (MF) (7.5 picoTesla; 5 Hz) placed over the scalp for a 7 minute period on three different days resulted in a complete resolution of symptoms within two weeks of initiation of treatment. Partial relief of the neuralgic pain and headaches was obtained immediately after completion of the first treatment indicating that resolution of symptoms was related to the effects of MF and not to a spontaneous remission. This is the first report demonstrating the clinical efficacy of pico Tesla range MF in rapidly resolving an acute relapse of MS.

Current concepts of the pathogenesis of optic neuritis associated with multiple sclerosis

Optic neuritis may occur as an isolated entity or as a manifestation of multiple sclerosis (MS), a widespread central nervous system demyelinating disease. Clinical, electrophysiological, magnetic resonance imaging and neuropathologic data support the hypothesis that "idiopathic" optic neuritis represents a restricted form of MS. The current evidence for viral, cell mediated, and antibody-induced etiologies of MS and optic neuritis are reviewed.