Low myo-inositol and high glutamine levels in brain are associated with neuropsychological deterioration after induced hyperammonemia.

نویسندگان

  • D L Shawcross
  • S Balata
  • S W M Olde Damink
  • P C Hayes
  • J Wardlaw
  • I Marshall
  • N E P Deutz
  • R Williams
  • R Jalan
چکیده

The neuropsychological effect of hyperammonemia is variable. This study tests the hypothesis that the effect of ammonia on the neuropsychological function in patients with cirrhosis is determined by the ability of the brain to buffer ammonia-induced increase in glutamine within the astrocyte by losing osmolytes like myo-inositol (mI) and not by the magnitude of the induced hyperammonemia. Fourteen cirrhotic patients with no evidence of overt hepatic encephalopathy were given a 75-g amino acid (aa) solution mimicking the hemoglobin molecule to induce hyperammonemia. Measurement of a battery of neuropsychological function tests including immediate memory, ammonia, aa, and short-echo time proton magnetic resonance spectroscopy were performed before and 4 h after administration of the aa solution. Eight patients showed deterioration in the Immediate Memory Test at 4 h. Demographic factors, severity of liver disease, change in plasma ammonia, and aa profiles after the aa solution were similar in those that showed a deterioration compared with those who did not. In patients who showed deterioration in the memory test, the mI-to-creatine ratio (mI/Cr) was significantly lower at baseline than those that did not deteriorate. In contrast, the glutamate/glutamine-to-Cr ratio was significantly greater in the patients that deteriorated. The observation that deterioration in the memory test scores was greater in those with lower mI/Cr supports the hypothesis that the neuropsychological effects of induced hyperammonemia is determined by the capacity of the brain to handle ammonia-induced increase in glutamine.

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منابع مشابه

TRANSLATIONAL PHYSIOLOGY Low myo-inositol and high glutamine levels in brain are associated with neuropsychological deterioration after induced hyperammonemia

D. L. Shawcross,* S. Balata,* S. W. M. Olde Damink, P. C. Hayes, J. Wardlaw, I. Marshall, N. E. P. Deutz, R. Williams, and R. Jalan Liver Failure Group, Institute of Hepatology, University College London, London, WC1E 6HX United Kingdom; The Scottish Liver Transplantation Unit, Royal Infirmary of Edinburgh, Edinburgh EH3 9YW; Department of Surgery, Academic Hospital, Maastricht University, 6229...

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Low myo-inositol and high glutamine levels in the brain are associated with neuropsychological deterioration following induced hyperammonemia

Background: The neuropsychological effect of hyperammonemia is variable. This study tests the hypothesis that the effect of ammonia on the neuropsychological function in patients with cirrhosis is determined by the ability of the brain to ‘buffer’ ammonia-induced increase in glutamine within the astrocyte by losing osmolytes like myo-inositol (mI) and not by the magnitude of the ‘induced hypera...

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عنوان ژورنال:
  • American journal of physiology. Gastrointestinal and liver physiology

دوره 287 3  شماره 

صفحات  -

تاریخ انتشار 2004