Experimental studies on the pathogenesis of leucodystrophies. II. The effect of sphingolipids on various cell types in cultures from the nervous system

Cerebral white matter: neuroanatomy, clinical neurology, and neurobehavioral correlates

Lesions of the cerebral white matter (WM) result in focal neurobehavioral syndromes, neuropsychiatric phenomena, and dementia. The cerebral WM contains fiber pathways that convey axons linking cerebral cortical areas with each other and with subcortical structures, facilitating the distributed neural circuits that subserve sensorimotor function, intellect, and emotion. Recent neuroanatomical investigations reveal that these neural circuits are topographically linked by five groupings of fiber tracts emanating from every neocortical area: (1) cortico-cortical association fibers; (2) corticostriatal fibers; (3) commissural fibers; and cortico-subcortical pathways to (4) thalamus and (5) pontocerebellar system, brain stem, and/or spinal cord. Lesions of association fibers prevent communication between cortical areas engaged in different domains of behavior. Lesions of subcortical structures or projection/striatal fibers disrupt the contribution of subcortical nodes to behavior. Disconnection syndromes thus result from lesions of the cerebral cortex, subcortical structures, and WM tracts that link the nodes that make up the distributed circuits. The nature and the severity of the clinical manifestations of WM lesions are determined, in large part, by the location of the pathology: discrete neurological and neuropsychiatric symptoms result from focal WM lesions, whereas cognitive impairment across multiple domains--WM dementia--occurs in the setting of diffuse WM disease. We present a detailed review of the conditions affecting WM that produce these neurobehavioral syndromes, and consider the pathophysiology, clinical effects, and broad significance of the effects of aging and vascular compromise on cerebral WM, in an attempt to help further the understanding, diagnosis, and treatment of these disorders.

Immune response in leukodystrophies

Although the genetics and biochemistry of leukodystrophies have been extensively explored, the immune response in these disorders has received relatively little attention. Both the disease course and its response to treatment may be highly dependent on the immune system. In this review, we compare three common leukodystrophies, each with a different immune response: (1) X-linked adrenoleukodystrophy, which demonstrates a severe, lymphocytic inflammatory response; (2) metachromatic leukodystrophy, which yields a histiocytic response; and (3) vanishing white-matter disease, in which no inflammation is typically seen. We highlight the biochemical, pathologic, and clinical differences, while focusing on the immune response in each disease. We also review the response of leukodystrophies to immunomodulatory therapies and interventions such as hematopoietic stem-cell transplantation. Future studies may delineate specific inflammatory markers as possible candidates for therapeutic intervention.

Reactions of vessel walls and brain parenchyma to the accumulation of Gaucher cells in the Norrbottnian type (type III) of Gaucher disease

Splenectomy in children with the Norrbottnian type of Gaucher disease is followed by increased blood levels of glucosylceramide and impaired neurological and mental status. High blood levels are associated with an increased accumulation of glucosylceramide in perivascular Gaucher cells in the brain compared to non-splenectomised cases. Surrounding the Gaucher cell infiltrates there is loss of neurons and slight demyelination in the brain parenchyma. The brains of four cases with the Norrbottnian type of Gaucher disease were examined by immunohistochemical stains in an attempt to further characterize the perivascular Gaucher cells and to examine the reactions of the vessel walls and brain parenchyma to the accumulation of Gaucher cells. The perivascular storage cells showed granular staining with antibodies to muramidase and alpha 1-anti-chymotrypsin confirming that they are blood-derived macrophages belonging to the monocyte-macrophage system. The Gaucher cells contained material positive for antisera to plasma proteins strongly suggesting that large molecules (including glucosylceramide) can escape from the blood and be taken up by the macrophages in Gaucher disease. The storage cells were surrounded by a reticulin network stained by antisera to collagen type III, type IV and laminin. The infiltrates were bounded from the brain parenchyma by a membrane strongly positive with antiserum for the basal lamina protein collagen type IV and laminin. The formation of a basal lamina around the Gaucher cell cuffs probably constitutes a protective phenomenon governing the brain parenchyma against the foreign cells. A focal loss of neurons but only minor loss of axons could be demonstrated with the antiserum to neurofilament.(ABSTRACT TRUNCATED AT 250 WORDS)