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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Zinc deficiency is common in cirrhosis and has been involved in the altered nitrogen metabolism. In this study, we measured the effects of zinc supplementation on the dynamics of amino acid-derived urea synthesis in cirrhosis with mild or latent encephalopathy. The hepatic conversion of amino acids into urea was studied in eight patients with advanced cirrhosis under controlled conditions of substrate availability (continuous alanine infusion), before and after 3-month oral zinc sulfate supplementation (600 mg/d). Eight more patients, matched for hepatocellular failure and encephalopathy, served as controls. Plasma zinc levels were reduced in all patients and returned to normal after oral zinc. The alanine-stimulated urea nitrogen synthesis rate in relation to alpha-amino-N concentration--the functional hepatic nitrogen clearance--increased by 25% after zinc supplementation, i.e., more urea was produced at any alpha-amino-N concentration. Basal and alanine-induced glucagon decreased by 50%, and the ammonia response to alanine decreased by 30%. Psychometric tests improved, as did routine and dynamic liver function tests and the Child-Pugh score. Also, the plasma concentration of lipid peroxides was reduced by zinc. No significant changes were observed in the control group. Our data indicate that long-term oral zinc speeds up the kinetics of urea formation from amino acids and ammonia. Changes in the hormonal drive and/or the antioxidant activity of zinc might be involved in the general improvement in liver function, whereas the beneficial effects on encephalopathy might stem from decreased ammonia.
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PMID:Zinc supplementation and amino acid-nitrogen metabolism in patients with advanced cirrhosis. 862 Nov 38

Apart from increased blood ammonia, alterations in various other substances have been implicated in the pathogenesis of hepatic encephalopathy (HE). The role of trace elements like zinc and manganese has been described recently. Zinc is an essential trace element and functions as an antioxidant. Low zinc concentrations have been reported in patients with cirrhosis of the liver, particularly those with HE. Patients with fulminant hepatic failure and subacute hepatic failure have also been shown to have low serum zinc levels. In animal experiments, zinc supplementation leads to a reduction in blood ammonia. Zinc deficiency also leads to alteration of neurotransmitters like gamma aminobutyric acid and norepinephrine. Zinc supplementation has been tried in HE. It may have a role in mild chronic HE, though further trials are necessary. Increased serum manganese levels have been shown in acute and chronic hepatitis, cirrhosis and congenital disorders like Alagille's syndrome. High manganese content has been reported in the globus pallidus in animals as well as brain tissues of patients dying of HE. Miners with chronic manganese exposure have encephalopathy and extra-pyramidal features similar to HE. It has been postulated that manganese impairs neuronal oxidative metabolism. The role of manganese in the pathogenesis of HE and the possibility of its chelation as treatment need further study.
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PMID:Role of trace elements in hepatic encephalopathy: zinc and manganese. 1502 50

Central nervous system (CNS) concentrates almost 10% of total zinc in the human body. Imbalances in zinc concentration are associated with numerous CNS diseases. Zinc deficiency is associated with nervous anorexia, major depression, cognitive impairment, and uncontrolled behavior. Our data reveal that plasma zinc concentration is decreased in major depression and it significantly increases following sertraline or amitriptyline treatment. Also, we found that ZnCl2 administration while inducing morphine-dependence in rats significantly decreases the symptoms of opioid-withdrawal syndrome. Recent data incriminate zinc deficit in the development of encephalopathy following severe impairment of hepatic function. On the other hand, zinc content of certain brain areas in Alzheimer disease is twice that in controls. Parkinson disease is also associated with higher zinc concentrations in the brain than normal. The ratio plasma zinc- other bivalent cations is also important for normal brain function.
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PMID:[Zinc involvements in the brain]. 1838 91