Encephalopathy astrocytes

The transmissible spongiform encephalopathies, or prion diseases, are fatal neurodegenerative diseases characterized by spongiform changes, astrocytic gliomas, and neuronal loss resulting from the deposition of insoluble protein aggregates in neural cells. They include Creutzfeldt-Jakob disease in humans, scrapie in... 

Initially, there is a confused state, Korsakoff s psychosis, that is characterized by confabulation and loss of recent memory, although memory for past events may be unimpaired. Later, clear neurological signs develop - Wernicke s encephalopathy. This is characterized by nystagmus and extraocular palsy. Postmortem examination shows hemorrhagic lesions in the thalamus, pontine tegmentum, and mammillary body, with severe damage to astrocytes, neuronal dendrites, and myelin sheaths. 

Mignot C, Boespflug-Tanguy O, Gelot A, Dautigny A, Pham-Dinh D, Rodriguez D (2004) Alexander disease putative mechanisms of an astrocytic encephalopathy. Cell Mol Life Sci 61 369-385... 

Norenberg, M.D. Astrocytic-ammonia interactions in hepatic encephalopathy. Semin. Liver Dis. 1996 16 245-253... 

Pyruvate carboxylase deficiency is one of the genetic diseases grouped together under the clinical manifestations of Leigh s disease (subacute necrotizing encephalopathy). In the mild form, the patient presents early in life with delayed development and a mild-to-moderate lactic acidemia. Patients who survive are severely mentally retarded, and there is a loss of cerebral neurons. In the brain, pyruvate carboxylase is present in the astrocytes, which use TCA cycle intermediates to synthesize glutamine. This pathway is essential for neuronal survival. The major cause of the lactic acidemia is that cells dependent on pyruvate carboxylase for an anaplerotic supply of oxaloacetate cannot oxidize pyruvate in the TCA cycle (because of low oxaloacetate levels), and the liver cannot convert pyruvate to glucose (because the pyruvate carboxylase reaction is required for this pathway to occur), so the excess pyruvate is converted to lactate. 

Norenbeig MD. The role of astrocytes in hepatic encephalopathy. Neurochem. Pathol, 6, 13-33, 1987... 

Norenberg MD, Lapham LW. The astrocyte response in experimental portal-systemic encephalopathy An electron microscope study. J. Neuropathol. Exp. Neurol, 33, 422- 35, 1974... 

Schhess F, Gorg B, Fischer R, Desjardins P, Bidmon HJ, Herrmann A, Butterworth RF, Zilles K, Haussinger D. Ammonia induces MK-801 sensitive nitration and phosphorylation of protein tyrosine residues in rat astrocytes. FASEB J., 76(7), 739-741,2002 Schmidt W, Wolf G, Grungreiff K, Meier M, Reum T. Hepatic encephalopathy influences high affinity uptake of transmitter glutamate and aspartate into the hippocampal formation. Metab. Brain Dis., 5, 19-32, 1990... 

Gordon, R.A., G. Roberts, Z. Amin, R.H. WiUiams and F.P. Paloucek. (1998) Aggressive approach in the treatment of acute lead encephalopathy with an extraordinarily high concentration of lead. Arch. Pediatr. Adolesc. Med. 152 1100-1104 Gunnarson, E., G. Axehult, G. Baturina, S. Zelenin, M. Zelenina and A. Aperia. (2005) Lead induces increased water permeability in astrocytes expressing Aquaporin 4. Neuroscience 136 105-114... 

Hazell, A.S., Rao, K.V., Danbolt, N.C., Pow, D.V., and Butterworth, R.F., 2001. Selective down-regulation of the astrocyte glutamate transporters GLT-1 and GLAST within the medial thalamus in experimental Wernicke s encephalopathy. Journal of Neurochemistry. 78 560-568. 

Hazell, A.S., 2009. Astrocytes are a major target in thiamine deficiency and Wernicke s encephalopathy. Neurochemistry International. 55 129-135. 

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