Inflammatory Disorders of the Nervous System
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Acute disseminated encephalomyelitis (ADEM) is an acute inflammatory demyelinating disease of the brain and spinal cord characterized by widespread perivascular inflammation and demyelination and caused by an autoimmune attack on the brain, most commonly as a reaction to a viral infection. Microscopic pathology shows perivascular inflammation and patchy demyelination of the white matter tracts of the cerebral hemispheres, brainstem, spinal cord, and optic nerves. Significant axon destruction. ADEM is thought to be an autoimmune disease, partly because of the inability to isolate an infectious agent from the central nervous system, and because of experimental models of autoimmune diffuse white matter encephalomyelitis that can be induced in animals, or accidentally in humans, by injection of the myelin antigens with adjuvant. Acute necrotizing encephalopathy/acute hemorrhagic necrotizing encephalopathy is a devastating parainfectious encephalopathy originally described as a childhood illness, usually in the context of influenza, but later recognized in adults.
Diseases of the Nervous System
George Feuer, Felix A. de la Iglesia in Molecular Biochemistry of Human Disease, 2020
The nervous system shows many more specialized features compared to any other organ. This elaborate system contains complicated anatomical and functional structures and exhibits several unique metabolic processes. The signs of disorder in neurological functions also show variations according to the anatomic level of the nervous system involved. The incidence of Down’s disease is influenced by environmental and genetic factors which increase the occurence of nondisjunction and trisomy. The study of narcosis and excitation provides an initial tool when we evaluate various disease processes of the nervous system. Excitation in the central nervous system is associated with events leading to the firing of the neurons and generation of action potentials. Lesions of the nerves are associated with characteristic degenerative changes of injured nerve cells. These changes are primary or secondary, depending on the initial integrity of the axon and its interaction with the myelin sheath and the Schwann cell.
Diffusion Magnetic Resonance Imaging in the Central Nervous System
Shoogo Ueno in Bioimaging, 2020
The diffusion magnetic resonance imaging (dMRI) signal in available clinical scanners is insensitive to signal attenuation caused by intra-axonal diffusion in the perpendicular direction. The observation of anisotropic diffusion in the white matter led to the idea of estimating the directions of white matter fiber bundles and visualizing the fiber trajectories. Maple syrup urine disease is another example where dMRI has yielded insightful clinical images. Diffusion in nervous tissue deviates from simple Gaussian distribution because of the presence of barriers such as cell membranes and myelin. In this setting, the diffusion propagator is influenced not only by the intrinsic diffusivity but also by the microstructural characteristics of the barriers. The microstructural underpinnings behind the diffusion abnormalities differ among diseases and are not completely elucidated yet. The organization of biological tissues, and therefore the diffusion process within them, is anisotropic, i.e., dependent on direction.
Neural mobilization promotes nerve regeneration by nerve growth factor and myelin protein zero increased after sciatic nerve injury
Published in Growth Factors, 2015
Joyce Teixeira da Silva, Fabio Martinez dos Santos, Aline Caroline Giardini, Daniel de Oliveira Martins, Mara Evany de Oliveira, Adriano Polican Ciena, Vanessa Pacciari Gutierrez, Ii-sei Watanabe, Luiz Roberto G. de Britto, Marucia Chacur
Neurotrophins are crucial in relation to axonal regrowth and remyelination following injury; and neural mobilization (NM) is a noninvasive therapy that clinically is effective in neuropathic pain treatment, but its mechanisms remains unclear. We examined the effects of NM on the regeneration of sciatic nerve after chronic constriction injury (CCI) in rats. The CCI was performed on adult male rats, submitted to 10 sessions of NM, starting 14 days after CCI. Then, the nerves were analyzed using transmission electron microscopy and western blot for neural growth factor (NGF) and myelin protein zero (MPZ). We observed an increase of NGF and MPZ after CCI and NM. Electron microscopy revealed that CCI-NM samples had high numbers of axons possessing myelin sheaths of normal thickness and less inter-axonal fibrosis than the CCI. These data suggest that NM is effective in facilitating nerve regeneration and NGF and MPZ are involved in this effect.
Effect of postlactation iron deficiency on the composition of fatty acids of whole brain myelin
Published in Nutritional Neuroscience, 2010
María del Socorro Camarillo Romero, F. Bernardo Pliego-Rivero, Bertha Moreno Altamirano, Gloria A. Otero
The composition of myelin fatty acids isolated from Wistar male rat brains was analysed after induction of nutritional iron-deficiency from postnatal days 21–63. From whole brain, myelin was obtained as the fraction of total lipids by phase separation under mildly acidic conditions. Fatty acids were separated by methylation and determined by gas chromatography. Significant differences in the polyunsaturated fatty acids n-6/n-3 relationship as well as an increment of eicosapentaenoic, eicosadienoic and docosadienoic acids and a reduction of stearic acid were determined in iron-deficient rats. The observed changes of myelin fatty acid expression strongly suggest an increased membrane fluidity, possibly affecting its three-dimensional structure, something which could partially correlate with the cognitive and psychomotor impairments observed in iron-deficient children and adolescents. Due to the fact that no significant differences have been observed in brain weight or size under iron deficiency, the increased expression of eicosapentaenoic acid (EPA) during postlactation development may play a moderately neuroprotective role.
Remyelination in multiple sclerosis: realizing a long-standing challenge
Published in Expert Review of Neurotherapeutics, 2015
Multiple sclerosis (MS) is a multifaceted disease, in which an inflammatory autoimmune attack on the myelin in the central nervous system (CNS) leads to extensive demyelination and subsequent axonal pathology. The challenge for MS therapy is to combine effective immunomodulatory therapies with novel neuroprotective approaches that promote repair, in particular remyelination, beyond its limited spontaneous extent. Cumulative findings indicate that immunomodulatory treatments can induce neuroprotective outcomes and provide a supportive milieu for repair processes. Growing understanding of MS pathology together with biotechnological advances has resulted in promising strategies such as inhibitory molecules, monoclonal antibodies and cell therapies. Several candidates that have shown significant effects on the oligodendrocyte population and/or myelin synthesis in animal models are currently or soon to be tested in clinical trials.
Related Knowledge Centers
- Nerve Tissue
- Oligodendroglia
- Myelin Sheath
- Unmyelinated Nerve Fibers
- Central Nervous Systems
- Schwann Cells
- Cell Membrane Structures