Species-specific accumulation of ceramides in cerebrospinal fluid from encephalomyeloradiculoneurpathy patients associated with peripheral complement activation: A pilot study

Sphingolipid abnormalities in encephalomyeloradiculoneuropathy (EMRN) are associated with an anti-neutral glycolipid antibody

Accumulating evidence suggests that various sphingolipids and glycosphingolipids can act as mediators for inflammation or signaling molecules in the nervous system. In this article, we explore the molecular basis of a new neuroinflammatory disorder called encephalomyeloradiculoneuropathy (EMRN), which affects the brain, spinal cord, and peripheral nerves; in particular, we discuss whether glycolipid and sphingolipid dysmetabolism is present in patients with this disorder. This review will focus on the pathognomonic significance of sphingolipid and glycolipid dysmetabolism for the development of EMRN and the possible involvement of inflammation in the nervous system.

A pilot study assessing sphingolipids and glycolipids dysmetabolism in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus usually exhibits triad of symptoms including gait disturbance, urinary incontinence, and dementia with ventriculomegaly. Currently, its pathogenesis remains to be fully elucidated. To provide a better understanding of this order, we examined whether dysmetabolism of sphingolipids as major lipid components in the brain present in cerebrospinal fluid (CSF) of the patients. Here, we measured various sphingolipidsincluding ceramide and sphingomyelin and glycolipids by electrospray ionization-tandem mass spectrometry in the cerebrospinal fluid of 19 consecutive idiopathic normal pressure hydrocephalus patients, 49 Parkinson's disease patients, and 17 neurologically normal controls. The data showed that there was a significant and specific reduction of all galactosylceramide subspecies levels in idiopathic normal pressure hydrocephalus patients compared with other groups, whereas ceramide and sphingomyelin levels as well as other neutral glycolipids such as glucosylceramide and lactosylceramide were similar in both disease states. Multiple regression analysis of sex and age did not show any correlation with galactosylceramide levels. We also examined whether MMSE scores are correlated with sphingolipid levels in iNPH patients. A specific subspecies of sphingomyelin (d18:1/18:0) only exhibited a statistically significant negative correlation (p = 0.0473, R = -0.4604) with MMSE scores but no other sphingolipids in iNPH patients. These data strongly suggest that myelin-rich galactosylceramide metabolism is severely impaired in idiopathic normal pressure hydrocephalus patients and might serve as the basis of biomarker for this disorder.

The first pediatric anti-lactosylceramide antibody-positive encephalomyeloradiculoneuropathy

Introduction

The anti-lactosylceramide (LacCer) antibody is an anti-neutral glycolipid antibody that is involved in the pathogenesis of encephalomyeloradiculoneuropathy (EMRN). It causes acute and subacute injuries to both the central and peripheral nerves. However, no pediatric cases of anti-LacCer antibody-positive EMRN have been reported so far.

Case

A 12-year-old girl presented with signs of meningitis. She subsequently showed disturbance of consciousness and flaccid tetraplegia and was placed on mechanical ventilation due to respiratory failure. MRI showed lesions in the cerebral white matter, basal ganglia, medulla oblongata, as well as the anterior horn of the spinal cord at the C2 to Th1 and Th11 to L1 levels. Nerve-conduction studies showed axonal neuropathy of the motor nerves. After steroid pulse therapy, high-dose immunoglobulin therapy, and plasma exchange, the lesions gradually regressed, and the neurological symptoms improved steadily. The neurological sequelae were minimal at 6 months after disease onset. Although serum anti-aquaporin 4 and anti-myelin oligodendrocyte glycoprotein antibodies were negative, she showed positive anti-lactosylceramide antibody in both serum and cerebrospinal fluid, indicating that these antibodies may be involved in the pathogenesis of this disease.

Conclusion

The first pediatric case of anti-LacCer antibody-positive EMRN showed similar features to the same disease in adults. Anti-neutral glycolipid antibodies should be measured in children presenting with a wide range of neurological symptoms involving both central and peripheral nerves.