Multiple sclerosis (MS) is the leading cause of neurological disability in young adults, affecting some two million people worldwide. Traditionally, MS has been considered a chronic, inflammatory disorder of the central white matter in which ensuing demyelination results in physical disability [Frohman EM, Racke MK, Raine CS (2006) N Engl J Med 354:942–955]. More recently, MS has become increasingly viewed as a neurodegenerative disorder in which neuronal loss, axonal injury, and atrophy of the CNS lead to permanent neurological and clinical disability. Although axonal pathology and loss in MS has been recognized for >100 years, very little is known about the underlying molecular mechanisms. Progressive axonal loss in MS may stem from a cascade of ionic imbalances initiated by inflammation, leading to mitochondrial dysfunction and energetic deficits that result in mitochondrial and cellular Ca2+ overload. In a murine disease model, experimental autoimmune encephalomyelitis (EAE) mice lacking cyclophilin D (CyPD), a key regulator of the mitochondrial permeability transition pore (PTP), developed EAE, but unlike WT mice, they partially recovered. Examination of the spinal cords of CyPD-knockout mice revealed a striking preservation of axons, despite a similar extent of inflammation. Furthermore, neurons prepared from CyPD-knockout animals were resistant to reactive oxygen and nitrogen species thought to mediate axonal damage in EAE and MS, and brain mitochondria lacking CyPD sequestered substantially higher levels of Ca2+. Our results directly implicate pathological activation of the mitochondrial PTP in the axonal damage occurring during MS and identify CyPD, as well as the PTP, as a potential target for MS neuroprotective therapies.

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Lipoic acid (LA) is an antioxidant that suppresses and treats an animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis. The purpose of this study was to determine the pharmacokinetics (PK), tolerability and effects on matrix metalloproteinase-9 (MMP-9) and soluble intercellular adhesion molecule-1 (sICAMP-1) of oral LA in patients with MS. Thirty-seven MS subjects were randomly assigned to one of four groups: placebo, LA 600 mg twice a day, LA 1200 mg once a day and LA 1200 mg twice a day. Subjects took study capsules for 14 days. We found that subjects taking 1200 mg LA had substantially higher peak serum LA levels than those taking 600 mg and that peak levels varied considerably among subjects. We also found a significant negative correlation between peak serum LA levels and mean changes in serum MMP-9 levels (T = -0.263, P =0.04). There was a significant dose response relationship between LA and mean change in serum sICAM-1 levels (P =0.03). We conclude that oral LA is generally well tolerated and appears capable of reducing serum MMP-9 and sICAM-1 levels. LA may prove useful in treating MS by inhibiting MMP-9 activity and interfering with T-cell migration into the CNS.

While a very-low fat, plant-based diet was well adhered to and tolerated, it resulted in no significant improvement on brain MRI, relapse rate or disability as assessed by EDSS scores in subjects with RRMS over one year. The diet group however showed significant improvements in measures of fatigue, BMI and metabolic biomarkers. The study was powered to detect only very large effects on MRI activity so smaller but clinically meaningful effects cannot be excluded. The diet intervention resulted in a beneficial effect on the self-reported outcome of fatigue but these results should be interpreted cautiously as a wait-list control group may not completely control for a placebo effect and there was a baseline imbalance on fatigue scores between the groups. If maintained, the improved lipid profile and BMI could yield long-term vascular health benefits. Longer studies with larger sample sizes are needed to better understand the long-term health benefits of this diet.

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Objective To describe Japanese macaque encephalomyelitis (JME), a spontaneous inflammatory demyelinating disease occurring in the Oregon National Primate Research Center’s (ONPRC) colony of Japanese macaques (JM, Macaca fuscata). Methods JM with neurologic impairment were removed from the colony, evaluated and treated with supportive care. Animals were humanely euthanized and their central nervous system (CNS) examined. Results ONPRC’s JM colony was established in 1965 and no cases of JME occurred until 1986. Since 1986, 56 JM spontaneously developed a disease characterized clinically by paresis of one or more limbs, ataxia or ocular motor paresis. Most animals were humanely euthanized during their initial episode. Three recovered, later relapsed and were then euthanized. There was no gender predilection and the median age for disease was 4 years. Magnetic resonance imaging of eight cases of JME revealed multiple gadolinium enhancing T1-weighted hyperintensities in the white matter of the cerebral hemispheres, brainstem, cerebellum and cervical spinal cord. The CNS of monkeys with JME contained multifocal plaque-like demyelinated lesions of varying ages, including acute and chronic, active demyelinating lesions with macrophages and lymphocytic periventricular infiltrates, and chronic, inactive demyelinated lesions. A previously undescribed gamma-herpesvirus was cultured from acute JME white matter lesions. Cases of JME continue to affect 1–3% of the ONPRC colony per year. Interpretation JME is a unique spontaneous disease in a nonhuman primate that has similarities with multiple sclerosis (MS) and is associated with a novel simian herpesvirus. Elucidating the pathogenesis of JME may shed new light on MS and other human demyelinating diseases.

The antioxidant lipoic acid (LA) treats and prevents the animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE). In an effort to understand the therapeutic potential of LA in MS, we sought to define the cellular mechanisms that mediate the effects of LA on human natural killer (NK) cells, which are important in innate immunity as the first line of defense against invading pathogens and tumor cells. We discovered that LA stimulates cAMP production in NK cells in a dose-dependent manner. Studies using pharmacological inhibitors and receptor transfection experiments indicate that LA stimulates cAMP production via activation of the EP2 and EP4 prostanoid receptors and adenylyl cyclase. In addition, LA suppressed interleukin (IL)-12/IL-18 induced IFNgamma secretion and cytotoxicity in NK cells. These novel findings suggest that LA may inhibit NK cell function via the cAMP signaling pathway.