Role of manganese in the pathogenesis of portal-systemic encephalopathy

Amongst the potential neurotoxins implicated in the pathogenesis of hepatic encephalopathy, manganese emerges as a new candidate. In patients with chronic liver diseases, manganese accumulates in blood and brain leading to pallidal signal hyperintensity on T1-weighted Magnetic Resonance (MR) Imaging...

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Bibliographic Details
Published in:Metabolic brain disease 1998-12, Vol.13 (4), p.311-317
Main Authors: POMIER LAYRARGUES, G, ROSE, C, SPAHR, L, ZAYED, J, NORMANDIN, L, BUTTERWORTH, R. F
Format: Article
Language:English
Subjects:
Biological and medical sciences
Brain - metabolism
Chronic Disease
Gastroenterology. Liver. Pancreas. Abdomen
Hepatic Encephalopathy - etiology
Hepatic Encephalopathy - metabolism
Humans
Liver Cirrhosis - metabolism
Liver Cirrhosis - physiopathology
Liver Diseases - metabolism
Liver. Biliary tract. Portal circulation. Exocrine pancreas
Manganese - metabolism
Manganese - physiology
Medical sciences
Nervous System - physiopathology
Other diseases. Semiology
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Summary:Amongst the potential neurotoxins implicated in the pathogenesis of hepatic encephalopathy, manganese emerges as a new candidate. In patients with chronic liver diseases, manganese accumulates in blood and brain leading to pallidal signal hyperintensity on T1-weighted Magnetic Resonance (MR) Imaging. Direct measurements in globus pallidus obtained at autopsy from cirrhotic patients who died in hepatic coma reveal 2 to 7-fold increases of manganese concentration. The intensity of pallidal MR images correlates with blood manganese and with the presence of extrapyramidal symptoms occurring in a majority of cirrhotic patients. Liver transplantation results in normalization of pallidal MR signals and disappearance of extrapyramidal symptoms whereas transjugular intrahepatic portosystemic shunting induces an increase in pallidal hyperintensity with a concomitant deterioration of neurological dysfunction. These findings suggest that the toxic effects of manganese contribute to extrapyramidal symptoms in patients with chronic liver disease. The mechanisms of manganese neurotoxicity are still speculative, but there is evidence to suggest that manganese deposition in the pallidum may lead to dopaminergic dysfunction. Future studies should be aimed at evaluating the effects of manganese chelation and/or of treatment of the dopaminergic deficit on neurological symptomatology in these patients.
ISSN:0885-7490
1573-7365
DOI:10.1023/A:1020636809063